CINXE.COM
Utilizing Industrial Sludge Ash in Brick Manufacturing and Quality Improvement - PMC
<!DOCTYPE html> <html lang="en" > <head > <meta charset="UTF-8" /> <meta http-equiv="X-UA-Compatible" content="IE=edge" /> <meta name="HandheldFriendly" content="True" /> <meta name="MobileOptimized" content="320" /> <meta name="viewport" content="width=device-width, initial-scale=1.0" /> <link rel="stylesheet" href="/static/assets/style-70b9163a.css" /> <script type="module" crossorigin="" src="/static/assets/base_style-ec2bc71e.js"></script> <link rel="stylesheet" href="/static/assets/style-ef962842.css" /> <link rel="stylesheet" href="/static/assets/style-3ade8b5c.css" /> <script type="module" crossorigin="" src="/static/assets/article_style-d757a0dd.js"></script> <style> @media screen and (min-width: 64em) { div.pmc-wm { background: repeat-y; background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='20' height='350' xmlns:xlink='http://www.w3.org/1999/xlink'%3E%3Cdefs%3E%3Cfilter x='-.02' y='0' width='1.05' height='1' id='c'%3E%3CfeFlood flood-color='%23FFF'/%3E%3CfeComposite in='SourceGraphic'/%3E%3C/filter%3E%3Ctext id='b' font-family='Helvetica' font-size='11pt' style='opacity:1;fill:%23005ea2;stroke:none;text-anchor:middle' x='175' y='14'%3E%3C/text%3E%3Cpath id='a' style='fill:%23005ea2' d='M0 8h350v3H0z'/%3E%3C/defs%3E%3Cuse xlink:href='%23a' transform='rotate(90 10 10)'/%3E%3Cuse xlink:href='%23b' transform='rotate(90 10 10)' filter='url(%23c)'/%3E%3C/svg%3E"); padding-left: 3rem; } } </style> <link rel="apple-touch-icon" sizes="180x180" href="/static/img/favicons/apple-touch-icon.png" /> <link rel="icon" type="image/png" sizes="48x48" href="/static/img/favicons/favicon-48x48.png" /> <link rel="icon" type="image/png" sizes="32x32" href="/static/img/favicons/favicon-32x32.png" /> <link rel="icon" type="image/png" sizes="16x16" href="/static/img/favicons/favicon-16x16.png" /> <link rel="manifest" href="/static/img/favicons/site.webmanifest" /> <link rel="mask-icon" href="/static/img/favicons/safari-pinned-tab.svg" color="#0071bc" /> <meta name="msapplication-config" content="/static/img/favicons/browserconfig.xml" /> <meta name="theme-color" content="#ffffff" /> <title> Utilizing Industrial Sludge Ash in Brick Manufacturing and Quality Improvement - PMC </title> <!-- Logging params: Pinger defaults --> <meta name="ncbi_app" content="cloudpmc-viewer" /> <meta name="ncbi_db" content="pmc" /> <meta name="ncbi_phid" content="E5FD02A8746DC3230602A8002137BA3A.m_1" /> <!-- Logging params: Pinger custom --> <meta name="ncbi_pdid" content="article" /> <link rel="preconnect" href="https://www.google-analytics.com" /> <link rel="dns-prefetch" href="https://cdn.ncbi.nlm.nih.gov" /> <link rel="preconnect" href="https://code.jquery.com" /> <meta name="ncbi_domain" content="materials"> <meta name="ncbi_type" content="fulltext"> <meta name="ncbi_pcid" content="journal"> <meta name="ncbi_feature" content="associated_data"> <link rel="canonical" href="https://pmc.ncbi.nlm.nih.gov/articles/PMC11173697/"> <meta name="robots" content="INDEX,NOFOLLOW,NOARCHIVE"> <meta name="citation_journal_title" content="Materials"> <meta name="citation_title" content="Utilizing Industrial Sludge Ash in Brick Manufacturing and Quality Improvement"> <meta name="citation_author" content="Yu-Ming Huang"> <meta name="citation_author_institution" content="Department of Resources Engineering, National Cheng Kung University, Tainan City 701, Taiwanianlai4568@gmail.com (J.-W.L.)"> <meta name="citation_author" content="Chao-Shi Chen"> <meta name="citation_author_institution" content="Department of Resources Engineering, National Cheng Kung University, Tainan City 701, Taiwanianlai4568@gmail.com (J.-W.L.)"> <meta name="citation_author" content="Chen-Chung Chen"> <meta name="citation_author_institution" content="Department of Resources Engineering, National Cheng Kung University, Tainan City 701, Taiwanianlai4568@gmail.com (J.-W.L.)"> <meta name="citation_author" content="Jian-Wen Lai"> <meta name="citation_author_institution" content="Department of Resources Engineering, National Cheng Kung University, Tainan City 701, Taiwanianlai4568@gmail.com (J.-W.L.)"> <meta name="citation_publication_date" content="2024 May 27"> <meta name="citation_volume" content="17"> <meta name="citation_issue" content="11"> <meta name="citation_firstpage" content="2568"> <meta name="citation_doi" content="10.3390/ma17112568"> <meta name="citation_pmid" content="38893832"> <meta name="citation_abstract_html_url" content="https://pmc.ncbi.nlm.nih.gov/articles/PMC11173697/"> <meta name="citation_fulltext_html_url" content="https://pmc.ncbi.nlm.nih.gov/articles/PMC11173697/"> <meta name="citation_pdf_url" content="https://pmc.ncbi.nlm.nih.gov/articles/PMC11173697/pdf/materials-17-02568.pdf"> <meta name="description" content="This research demonstrates changes in the behaviors and characteristics of sintered bricks while using industrial sludge ash (ISA) and waste glass (WG) as a replacement for clay in the brick manufacturing procedure. Owing to the limited amount of ..."> <meta name="og:title" content="Utilizing Industrial Sludge Ash in Brick Manufacturing and Quality Improvement"> <meta name="og:type" content="article"> <meta name="og:site_name" content="PubMed Central (PMC)"> <meta name="og:description" content="This research demonstrates changes in the behaviors and characteristics of sintered bricks while using industrial sludge ash (ISA) and waste glass (WG) as a replacement for clay in the brick manufacturing procedure. Owing to the limited amount of ..."> <meta name="og:url" content="https://pmc.ncbi.nlm.nih.gov/articles/PMC11173697/"> <meta name="og:image" content="https://cdn.ncbi.nlm.nih.gov/pmc/cms/images/pmc-card-share.jpg?_=0"> <meta name="twitter:card" content="summary_large_image"> <meta name="twitter:site" content="@ncbi"> </head> <body > <a class="usa-skipnav " href="#main-content"> Skip to main content </a> <section class="usa-banner " aria-label="Official website of the United States government" > <div class="usa-accordion"> <header class="usa-banner__header"> <div class="usa-banner__inner"> <div class="grid-col-auto"> <img aria-hidden="true" class="usa-banner__header-flag" src="/static/img/us_flag.svg" alt="" /> </div> <div class="grid-col-fill tablet:grid-col-auto" aria-hidden="true"> <p class="usa-banner__header-text"> An official website of the United States government </p> <span class="usa-banner__header-action">Here's how you know</span> </div> <button type="button" class="usa-accordion__button usa-banner__button " aria-expanded="false" aria-controls="gov-banner-default" data-testid="storybook-django-banner" > <span class="usa-banner__button-text">Here's how you know</span> </button> </div> </header> <div class="usa-banner__content usa-accordion__content" id="gov-banner-default" hidden> <div class="grid-row grid-gap-lg"> <div class="usa-banner__guidance tablet:grid-col-6"> <img class="usa-banner__icon usa-media-block__img" src="/static/img/icon-dot-gov.svg" alt="" aria-hidden="true" /> <div class="usa-media-block__body"> <p> <strong>Official websites use .gov</strong> <br /> A <strong>.gov</strong> website belongs to an official government organization in the United States. </p> </div> </div> <div class="usa-banner__guidance tablet:grid-col-6"> <img class="usa-banner__icon usa-media-block__img" src="/static/img/icon-https.svg" alt="" aria-hidden="true" /> <div class="usa-media-block__body"> <p> <strong>Secure .gov websites use HTTPS</strong> <br /> A <strong>lock</strong> ( <span class="icon-lock"> <svg xmlns="http://www.w3.org/2000/svg" width="52" height="64" viewBox="0 0 52 64" class="usa-banner__lock-image" role="graphics-symbol" aria-labelledby="banner-lock-description" focusable="false"> <title id="banner-lock-title">Lock</title> <desc id="banner-lock-description"> Locked padlock icon </desc> <path fill="#000000" fill-rule="evenodd" d="M26 0c10.493 0 19 8.507 19 19v9h3a4 4 0 0 1 4 4v28a4 4 0 0 1-4 4H4a4 4 0 0 1-4-4V32a4 4 0 0 1 4-4h3v-9C7 8.507 15.507 0 26 0zm0 8c-5.979 0-10.843 4.77-10.996 10.712L15 19v9h22v-9c0-6.075-4.925-11-11-11z" /> </svg> </span>) or <strong>https://</strong> means you've safely connected to the .gov website. Share sensitive information only on official, secure websites. </p> </div> </div> </div> </div> </div> </section> <div class="usa-overlay"> </div> <header class="usa-header usa-header--extended usa-header--wide" data-testid="header" data-header > <div class="ncbi-header"> <div class="ncbi-header__container"> <a class="ncbi-header__logo-container" href="/"> <img alt=" PMC home page " class="ncbi-header__logo-image" src="/static/img/ncbi-logos/nih-nlm-ncbi--white.svg" /> </a> <!-- Mobile menu hamburger button --> <button type="button" class="usa-menu-btn ncbi-header__hamburger-button " aria-label="Show menu" data-testid="navMenuButton" > <svg aria-hidden="true" class="ncbi-hamburger-icon" fill="none" focusable="false" height="21" viewBox="0 0 31 21" width="31" xmlns="http://www.w3.org/2000/svg"> <path clip-rule="evenodd" d="M0.125 20.75H30.875V17.3333H0.125V20.75ZM0.125 12.2083H30.875V8.79167H0.125V12.2083ZM0.125 0.25V3.66667H30.875V0.25H0.125Z" fill="#F1F1F1" fill-rule="evenodd" /> </svg> </button> <!-- Desktop buttons--> <div class="ncbi-header__desktop-buttons"> <!-- Desktop search button --> <button type="button" class="usa-button usa-button--unstyled ncbi-header__desktop-button " aria-expanded="false" aria-controls="search-field-desktop-navigation" aria-label="Show search overlay" data-testid="toggleSearchPanelButton" data-toggle-search-panel-button > <svg class="usa-icon " role="graphics-symbol" aria-hidden="true" > <use xlink:href="/static/img/sprite.svg#search" /> </svg> Search </button> <!-- Desktop login dropdown --> <div class="ncbi-header__login-dropdown"> <button type="button" class="usa-button usa-button--unstyled ncbi-header__desktop-button ncbi-header__login-dropdown-button " aria-expanded="false" aria-controls="login-dropdown-menu" aria-label="Show login menu" data-testid="toggleLoginMenuDropdown" data-desktop-login-button > <svg class="usa-icon " role="graphics-symbol" aria-hidden="true" > <use xlink:href="/static/img/sprite.svg#person" /> </svg> <span data-login-dropdown-text>Log in</span> <!-- Dropdown icon pointing up --> <svg class="usa-icon ncbi-header__login-dropdown-icon ncbi-header__login-dropdown-icon--expand-less ncbi-header__login-dropdown-icon--hidden" role="graphics-symbol" aria-hidden="true" data-login-dropdown-up-arrow> <use xlink:href="/static/img/sprite.svg#expand_less" /> </svg> <!-- Dropdown icon pointing down --> <svg class="usa-icon ncbi-header__login-dropdown-icon ncbi-header__login-dropdown-icon--expand-more ncbi-header__login-dropdown-icon--hidden" role="graphics-symbol" aria-hidden="true" data-login-dropdown-down-arrow> <use xlink:href="/static/img/sprite.svg#expand_more" /> </svg> </button> <!-- Login dropdown menu --> <ul class="usa-nav__submenu ncbi-header__login-dropdown-menu" id="login-dropdown-menu" data-desktop-login-menu-dropdown hidden> <li class="usa-nav__submenu-item"> <!-- Uses custom style overrides to render external and document links. --> <a href="https://www.ncbi.nlm.nih.gov/myncbi/" class="usa-link " > Dashboard </a> </li> <li class="usa-nav__submenu-item"> <!-- Uses custom style overrides to render external and document links. --> <a href="https://www.ncbi.nlm.nih.gov/myncbi/collections/bibliography/" class="usa-link " > Publications </a> </li> <li class="usa-nav__submenu-item"> <!-- Uses custom style overrides to render external and document links. --> <a href="https://www.ncbi.nlm.nih.gov/account/settings/" class="usa-link " > Account settings </a> </li> <li class="usa-nav__submenu-item"> <button type="button" class="usa-button usa-button--outline ncbi-header__login-dropdown-logout-button " data-testid="desktopLogoutButton" data-desktop-logout-button > Log out </button> </li> </ul> </div> </div> </div> </div> <!-- Search panel --> <div class="ncbi-search-panel ncbi--show-only-at-desktop" data-testid="searchPanel" data-header-search-panel hidden> <div class="ncbi-search-panel__container"> <form action="https://www.ncbi.nlm.nih.gov/search/all/" aria-describedby="search-field-desktop-navigation-help-text" autocomplete="off" class="usa-search usa-search--big ncbi-search-panel__form" data-testid="form" method="GET" role="search"> <label class="usa-sr-only" data-testid="label" for="search-field-desktop-navigation"> Search… </label> <input class="usa-input" data-testid="textInput" id="search-field-desktop-navigation" name="term" placeholder="Search NCBI" type="search" value="" /> <button type="submit" class="usa-button " data-testid="button" > <span class="usa-search__submit-text"> Search NCBI </span> </button> </form> </div> </div> <nav aria-label="Primary navigation" class="usa-nav"> <p class="usa-sr-only" id="primary-navigation-sr-only-title"> Primary site navigation </p> <!-- Mobile menu close button --> <button type="button" class="usa-nav__close ncbi-nav__close-button " aria-label="Close navigation menu" data-testid="navCloseButton" > <img src="/static/img/usa-icons/close.svg" alt="Close" /> </button> <!-- Mobile search component --> <form class="usa-search usa-search--small ncbi--hide-at-desktop margin-top-6" role="search"> <label class="usa-sr-only" for="search-field"> Search </label> <input class="usa-input" id="search-field-mobile-navigation" type="search" placeholder="Search NCBI" name="search" /> <button type="submit" class="usa-button " > <!-- This SVG should be kept inline and not replaced with a link to the icon as otherwise it will render in the wrong color --> <img src="data:image/svg+xml;base64,PHN2ZyB4bWxucz0iaHR0cDovL3d3dy53My5vcmcvMjAwMC9zdmciIGhlaWdodD0iMjQiIHZpZXdCb3g9IjAgMCAyNCAyNCIgd2lkdGg9IjI0Ij48cGF0aCBkPSJNMCAwaDI0djI0SDB6IiBmaWxsPSJub25lIi8+PHBhdGggZmlsbD0iI2ZmZiIgZD0iTTE1LjUgMTRoLS43OWwtLjI4LS4yN0E2LjQ3MSA2LjQ3MSAwIDAgMCAxNiA5LjUgNi41IDYuNSAwIDEgMCA5LjUgMTZjMS42MSAwIDMuMDktLjU5IDQuMjMtMS41N2wuMjcuMjh2Ljc5bDUgNC45OUwyMC40OSAxOWwtNC45OS01em0tNiAwQzcuMDEgMTQgNSAxMS45OSA1IDkuNVM3LjAxIDUgOS41IDUgMTQgNy4wMSAxNCA5LjUgMTEuOTkgMTQgOS41IDE0eiIvPjwvc3ZnPg==" class="usa-search__submit-icon" alt="Search" /> </button> </form> <!-- Primary navigation menu items --> <!-- This usa-nav__inner wrapper is required to correctly style the navigation items on Desktop --> <div class="ncbi-nav__mobile-login-menu ncbi--hide-at-desktop" data-mobile-login-menu hidden> <p class="ncbi-nav__mobile-login-menu-status"> Logged in as: <strong class="ncbi-nav__mobile-login-menu-email" data-mobile-login-email-text></strong> </p> <ul class="usa-nav__primary usa-accordion"> <li class="usa-nav__primary-item"> <a href="https://www.ncbi.nlm.nih.gov/myncbi/" class="usa-link " > Dashboard </a> </li> <li class="usa-nav__primary-item"> <a href="https://www.ncbi.nlm.nih.gov/myncbi/collections/bibliography/" class="usa-link " > Publications </a> </li> <li class="usa-nav__primary-item"> <a href="https://www.ncbi.nlm.nih.gov/account/settings/" class="usa-link " > Account settings </a> </li> </ul> </div> <button type="button" class="usa-button ncbi-nav__mobile-login-button ncbi--hide-at-desktop " data-testid="mobileLoginButton" data-mobile-login-button > Log in </button> </nav> </header> <section class="pmc-header pmc-header--basic" aria-label="PMC Header with search box"> <div class="pmc-nav-container"> <div class="pmc-header__bar"> <div class="pmc-header__logo"> <a href="/" title="Home" aria-label="PMC Home"></a> </div> <button type="button" class="usa-button usa-button--unstyled pmc-header__search__button" aria-label="Open search" data-ga-category="search" data-ga-action="PMC" data-ga-label="pmc_search_panel_mobile" > <svg class="usa-icon width-4 height-4 pmc-icon__open" aria-hidden="true" focusable="false" role="img"> <use xlink:href="/static/img/sprite.svg#search"></use> </svg> <svg class="usa-icon width-4 height-4 pmc-icon__close" aria-hidden="true" focusable="false" role="img"> <use xlink:href="/static/img/sprite.svg#close"></use> </svg> </button> </div> <div class="pmc-header__search"> <form class="usa-search usa-search--extra usa-search--article-right-column pmc-header__search__form" autocomplete="off" role="search"> <label class="usa-sr-only" for="pmc-search">Search PMC Full-Text Archive</label> <span class="autoComplete_wrapper flex-1"> <input class="usa-input width-full maxw-none" required="required" placeholder="Search PMC Full-Text Archive" id="pmc-search" type="search" name="term" data-autocomplete-url="/search/autocomplete/"/> </span> <button class="usa-button" type="submit" formaction="https://www.ncbi.nlm.nih.gov/pmc/" data-ga-category="search" data-ga-action="PMC" data-ga-label="PMC_search_button" > <span class="usa-search__submit-text">Search in PMC</span> <img src="/static/img/usa-icons-bg/search--white.svg" class="usa-search__submit-icon" alt="Search" /> </button> </form> <ul class="pmc-header__search__menu"> <li> <a class="usa-link" href="https://www.ncbi.nlm.nih.gov/pmc/advanced/" data-ga-action="featured_link" data-ga-label="advanced_search"> Advanced Search </a> </li> <li> <a class="usa-link" href="/journals/" data-ga-action="featured_link" data-ga-label="journal list"> Journal List </a> </li> <li> <a class="usa-link" href="/about/userguide/" data-ga-action="featured_link" data-ga-label="user guide"> User Guide </a> </li> </ul> </div> </div> </section> <div class="usa-section padding-top-0 desktop:padding-top-6 pmc-article-section" data-article-db="pmc" data-article-id="11173697"> <div class="grid-container pmc-actions-bar" aria-label="Actions bar" role="complementary"> <div class="grid-row"> <div class="grid-col-fill display-flex"> <div class="display-flex"> <ul class="usa-list usa-list--unstyled usa-list--horizontal"> <li class="margin-right-2 mobile-lg:margin-right-4 display-flex mob"> <button type="button" class="usa-button pmc-sidenav__container__open usa-button--unstyled width-auto display-flex" aria-label="Open resources" data-extra-class="is-visible-resources" data-ga-category="resources_accordion" data-ga-action="click" data-ga-label="mobile_icon" > <svg class="usa-icon width-4 height-4" aria-hidden="true" focusable="false" role="img"> <use xlink:href="/static/img/sprite.svg#more_vert"></use> </svg> </button> </li> <li class="margin-right-2 mobile-lg:margin-right-4 display-flex mob"> <a href="https://doi.org/10.3390/ma17112568" class="usa-link display-flex" role="button" target="_blank" rel="noreferrer noopener" aria-label="View on publisher site" data-ga-category="actions" data-ga-action="click" data-ga-label="publisher_link_mobile" > <svg class="usa-icon width-4 height-4" aria-hidden="true" focusable="false" role="img"> <use xlink:href="/static/img/sprite.svg#launch"></use> </svg> </a> </li> <li class="margin-right-2 mobile-lg:margin-right-4 display-flex"> <a href="pdf/materials-17-02568.pdf" class="usa-link display-flex" role="button" aria-label="Download PDF" data-ga-category="actions" data-ga-action="click" data-ga-label="pdf_download_mobile" > <svg class="usa-icon width-4 height-4" aria-hidden="true" focusable="false" role="img"> <use xlink:href="/static/img/sprite.svg#file_download"></use> </svg> </a> </li> <li class="margin-right-2 mobile-lg:margin-right-4 display-flex"> <button class="usa-button usa-button--unstyled collections-dialog-trigger collections-button display-flex collections-button-empty" aria-label="Save article in MyNCBI collections." data-ga-category="actions" data-ga-action="click" data-ga-label="collections_button_mobile" data-collections-open-dialog-enabled="false" data-collections-open-dialog-url="https://account.ncbi.nlm.nih.gov/?back_url=https%3A%2F%2Fpmc.ncbi.nlm.nih.gov%2Farticles%2FPMC11173697%2F%23open-collections-dialog" data-in-collections="false" > <svg class="usa-icon width-4 height-4 usa-icon--bookmark-full" aria-hidden="true" focusable="false" role="img" hidden> <use xlink:href="/static/img/action-bookmark-full.svg#icon"></use> </svg> <svg class="usa-icon width-4 height-4 usa-icon--bookmark-empty" aria-hidden="true" focusable="false" role="img" hidden> <use xlink:href="/static/img/action-bookmark-empty.svg#icon"></use> </svg> </button> </li> <li class="margin-right-2 mobile-lg:margin-right-4 display-flex"> <button role="button" class="usa-button usa-button--unstyled citation-dialog-trigger display-flex" aria-label="Open dialog with citation text in different styles" data-ga-category="actions" data-ga-action="open" data-ga-label="cite_mobile" data-all-citations-url="/resources/citations/11173697/" data-citation-style="nlm" data-download-format-link="/resources/citations/11173697/export/" > <svg class="usa-icon width-4 height-4 usa-icon--bookmark-empty" aria-hidden="true" focusable="false" role="img" hidden> <use xlink:href="/static/img/sprite.svg#format_quote"></use> </svg> </button> </li> <li class="pmc-permalink display-flex"> <button type="button" class="usa-button usa-button--unstyled display-flex" aria-label="Show article permalink" aria-expanded="false" aria-haspopup="true" data-ga-category="actions" data-ga-action="open" data-ga-label="permalink_mobile" > <svg class="usa-icon width-4 height-4" aria-hidden="true" focusable="false" role="img"> <use xlink:href="/static/img/sprite.svg#share"></use> </svg> </button> <div class="pmc-permalink__dropdown" hidden> <div class="pmc-permalink__dropdown__container"> <h2 class="usa-modal__heading margin-top-0 margin-bottom-2">PERMALINK</h2> <div class="pmc-permalink__dropdown__content"> <input type="text" class="usa-input" value="https://pmc.ncbi.nlm.nih.gov/articles/PMC11173697/" aria-label="Article permalink"> <button class="usa-button display-inline-flex pmc-permalink__dropdown__copy__btn margin-right-0" title="Copy article permalink" data-ga-category="save_share" data-ga-action="link" data-ga-label="copy_link"> <svg class="usa-icon" aria-hidden="true" focusable="false" role="img"> <use xlink:href="/static/img/sprite.svg#content_copy"></use> </svg> <span class="margin-left-1">Copy</span> </button> </div> </div> </div> </li> </ul> </div> <button type="button" class="usa-button pmc-sidenav__container__open usa-button--unstyled width-auto display-flex" aria-label="Open article navigation" data-extra-class="is-visible-in-page" data-ga-category="actions" data-ga-action="open" data-ga-label="article_nav_mobile" > <svg class="usa-icon width-4 height-4" aria-hidden="true" focusable="false" role="img"> <use xlink:href="/static/img/sprite.svg#list"></use> </svg> </button> </div> </div> </div> <div class="grid-container desktop:padding-left-6"> <div id="article-container" class="grid-row grid-gap"> <div class="grid-col-12 desktop:grid-col-8 order-2 pmc-layout__content"> <div class="grid-container padding-left-0 padding-right-0"> <div class="grid-row desktop:margin-left-neg-6"> <div class="grid-col-12"> <div class="pmc-layout__disclaimer" role="complementary" aria-label="Disclaimer note"> As a library, NLM provides access to scientific literature. Inclusion in an NLM database does not imply endorsement of, or agreement with, the contents by NLM or the National Institutes of Health.<br/> Learn more: <a class="usa-link" data-ga-category="Link click" data-ga-action="Disclaimer" data-ga-label="New disclaimer box" href="/about/disclaimer/">PMC Disclaimer</a> | <a class="usa-link" data-ga-category="Link click" data-ga-action="PMC Copyright Notice" data-ga-label="New disclaimer box" href="/about/copyright/"> PMC Copyright Notice </a> </div> </div> </div> <div class="grid-row pmc-wm desktop:margin-left-neg-6"> <!-- Main content --> <main id="main-content" class="usa-layout-docs__main usa-layout-docs grid-col-12 pmc-layout pmc-prose padding-0" > <section class="pmc-journal-banner text-center line-height-none" aria-label="Journal banner"><img src="https://cdn.ncbi.nlm.nih.gov/pmc/banners/logo-materials.png" alt="Materials logo" usemap="#pmc-banner-imagemap" width="500" height="75"><map name="pmc-banner-imagemap"><area alt="Link to Materials" title="Link to Materials" shape="default" href="http://www.mdpi.com/journal/materials" target="_blank" rel="noopener noreferrer"></map></section><article lang="en"><section aria-label="Article citation and metadata"><section class="pmc-layout__citation font-secondary font-xs"><div> <div class="display-inline-block"><button type="button" class="cursor-pointer text-no-underline bg-transparent border-0 padding-0 text-left margin-0 text-normal text-primary" aria-controls="journal_context_menu">Materials (Basel)</button></div>. 2024 May 27;17(11):2568. doi: <a href="https://doi.org/10.3390/ma17112568" class="usa-link usa-link--external" data-ga-action="click_feat_suppl" target="_blank" rel="noopener noreferrer">10.3390/ma17112568</a> </div> <nav id="journal_context_menu" hidden="hidden"><ul class="menu-list font-family-ui" role="menu"> <li role="presentation"><a href="https://www.ncbi.nlm.nih.gov/pmc/?term=%22Materials%20(Basel)%22%5Bjour%5D" class="usa-link" role="menuitem">Search in PMC</a></li> <li role="presentation"><a href="https://pubmed.ncbi.nlm.nih.gov/?term=%22Materials%20(Basel)%22%5Bjour%5D" lang="en" class="usa-link" role="menuitem">Search in PubMed</a></li> <li role="presentation"><a href="https://www.ncbi.nlm.nih.gov/nlmcatalog?term=%22Materials%20(Basel)%22%5BTitle%20Abbreviation%5D" class="usa-link" role="menuitem">View in NLM Catalog</a></li> <li role="presentation"><a href="?term=%22Materials%20(Basel)%22%5Bjour%5D" class="usa-link" role="menuitem" data-add-to-search="true">Add to search</a></li> </ul></nav></section><section class="front-matter"><div class="ameta p font-secondary font-xs"> <hgroup><h1>Utilizing Industrial Sludge Ash in Brick Manufacturing and Quality Improvement</h1></hgroup><div class="cg p"> <a href="https://pubmed.ncbi.nlm.nih.gov/?term=%22Huang%20YM%22%5BAuthor%5D" class="usa-link" aria-describedby="id1"><span class="name western">Yu-Ming Huang</span></a><div hidden="hidden" id="id1"> <h3><span class="name western">Yu-Ming Huang</span></h3> <div class="p"> <sup>1</sup>Department of Resources Engineering, National Cheng Kung University, Tainan City 701, Taiwanianlai4568@gmail.com (J.-W.L.)</div> <div>Writing – original draft</div> <div class="p">Find articles by <a href="https://pubmed.ncbi.nlm.nih.gov/?term=%22Huang%20YM%22%5BAuthor%5D" class="usa-link"><span class="name western">Yu-Ming Huang</span></a> </div> </div> <sup>1,</sup><sup>*</sup>, <a href="https://pubmed.ncbi.nlm.nih.gov/?term=%22Chen%20CS%22%5BAuthor%5D" class="usa-link" aria-describedby="id2"><span class="name western">Chao-Shi Chen</span></a><div hidden="hidden" id="id2"> <h3><span class="name western">Chao-Shi Chen</span></h3> <div class="p"> <sup>1</sup>Department of Resources Engineering, National Cheng Kung University, Tainan City 701, Taiwanianlai4568@gmail.com (J.-W.L.)</div> <div>Supervision</div> <div class="p">Find articles by <a href="https://pubmed.ncbi.nlm.nih.gov/?term=%22Chen%20CS%22%5BAuthor%5D" class="usa-link"><span class="name western">Chao-Shi Chen</span></a> </div> </div> <sup>1,</sup><sup>*</sup>, <a href="https://pubmed.ncbi.nlm.nih.gov/?term=%22Chen%20CC%22%5BAuthor%5D" class="usa-link" aria-describedby="id3"><span class="name western">Chen-Chung Chen</span></a><div hidden="hidden" id="id3"> <h3><span class="name western">Chen-Chung Chen</span></h3> <div class="p"> <sup>1</sup>Department of Resources Engineering, National Cheng Kung University, Tainan City 701, Taiwanianlai4568@gmail.com (J.-W.L.)</div> <div>Data curation</div> <div class="p">Find articles by <a href="https://pubmed.ncbi.nlm.nih.gov/?term=%22Chen%20CC%22%5BAuthor%5D" class="usa-link"><span class="name western">Chen-Chung Chen</span></a> </div> </div> <sup>1</sup>, <a href="https://pubmed.ncbi.nlm.nih.gov/?term=%22Lai%20JW%22%5BAuthor%5D" class="usa-link" aria-describedby="id4"><span class="name western">Jian-Wen Lai</span></a><div hidden="hidden" id="id4"> <h3><span class="name western">Jian-Wen Lai</span></h3> <div class="p"> <sup>1</sup>Department of Resources Engineering, National Cheng Kung University, Tainan City 701, Taiwanianlai4568@gmail.com (J.-W.L.)</div> <div>Data curation</div> <div class="p">Find articles by <a href="https://pubmed.ncbi.nlm.nih.gov/?term=%22Lai%20JW%22%5BAuthor%5D" class="usa-link"><span class="name western">Jian-Wen Lai</span></a> </div> </div> <sup>1</sup> </div> <div class="cg p">Editor: <span class="name western">Yuri Ribakov</span><sup>1</sup> </div> <ul class="d-buttons inline-list"> <li><button class="d-button" aria-controls="aip_a" aria-expanded="false">Author information</button></li> <li><button class="d-button" aria-controls="anp_a" aria-expanded="false">Article notes</button></li> <li><button class="d-button" aria-controls="clp_a" aria-expanded="false">Copyright and License information</button></li> </ul> <div class="d-panels font-secondary-light"> <div id="aip_a" class="d-panel p" style="display: none"> <div class="p" id="af1-materials-17-02568"> <sup>1</sup>Department of Resources Engineering, National Cheng Kung University, Tainan City 701, Taiwanianlai4568@gmail.com (J.-W.L.)</div> <div class="author-notes p"><div class="fn" id="c1-materials-17-02568"> <sup>*</sup><p class="display-inline">Correspondence: <span>n48091063@gs.ncku.edu.tw</span> (Y.-M.H.); <span>chencs@mail.ncku.edu.tw</span> (C.-S.C.)</p> </div></div> <h4 class="font-secondary">Roles</h4> <div class="p"> <strong class="contrib"><span class="name western">Yu-Ming Huang</span></strong>: <span class="role">Writing – original draft</span> </div> <div> <strong class="contrib"><span class="name western">Chao-Shi Chen</span></strong>: <span class="role">Supervision</span> </div> <div> <strong class="contrib"><span class="name western">Chen-Chung Chen</span></strong>: <span class="role">Data curation</span> </div> <div> <strong class="contrib"><span class="name western">Jian-Wen Lai</span></strong>: <span class="role">Data curation</span> </div> <div class="p"> <strong class="contrib"><span class="name western">Yuri Ribakov</span></strong>: <span class="role">Academic Editor</span> </div> </div> <div id="anp_a" class="d-panel p" style="display: none"><div class="notes p"><section id="historyarticle-meta1" class="history"><p>Received 2024 Mar 26; Revised 2024 May 15; Accepted 2024 May 24; Collection date 2024 Jun.</p></section></div></div> <div id="clp_a" class="d-panel p" style="display: none"> <div>© 2024 by the authors.</div> <p>Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (<a href="https://creativecommons.org/licenses/by/4.0/" class="usa-link usa-link--external" data-ga-action="click_feat_suppl" target="_blank" rel="noopener noreferrer">https://creativecommons.org/licenses/by/4.0/</a>).</p> <div class="p"><a href="/about/copyright/" class="usa-link">PMC Copyright notice</a></div> </div> </div> <div>PMCID: PMC11173697 PMID: <a href="https://pubmed.ncbi.nlm.nih.gov/38893832/" class="usa-link">38893832</a> </div> </div></section></section><section aria-label="Article content"><section class="body main-article-body"><section class="abstract" id="abstract1"><h2>Abstract</h2> <p>This research demonstrates changes in the behaviors and characteristics of sintered bricks while using industrial sludge ash (ISA) and waste glass (WG) as a replacement for clay in the brick manufacturing procedure. Owing to the limited amount of available land in Taiwan, it is becoming increasingly difficult to locate suitable sites for sanitary landfills, which is a common final disposal method for ash that is produced during thermal treatment in sludge factories. To meet the urgent need for land, the final waste disposal must convert this waste into a new resource. This research investigated the feasibility of using general industrial sludge ash waste, due to its abundance and high potential as a raw material in producing bricks. The result of this study shows that the bricks made from ISA and WG under a certain mixture proportion (ISA50%/WG40%/Clay10%) had excellent industrial potentials, such as compressive strength and water absorption rate. However, owing to the wide variety of components from different sources of ISA, the mixture proportion might vary accordingly. This study also analyzed the incineration index, proportion design, and process improvement, as well as investigating the possibility of increasing the total use of sludge ash as a resource. This study shows the potentials of utilizing wastes as raw materials in industrial manufacturing procedures. Therefore, more wastes can be tested and turned into resources in the future.</p> <section id="kwd-group1" class="kwd-group"><p><strong>Keywords:</strong> carbonation, industrial sludge ash, engineering properties, mechanical properties</p></section></section><section id="sec1-materials-17-02568"><h2 class="pmc_sec_title">1. Introduction</h2> <p>As the amount of industrial sludge waste has increased rapidly over recent decades and such waste comprises various components, thermal treatment has become increasingly necessary. Owing to the improvements in both technology and equipment, thermal treatment is now indispensable for managing sludge waste [<a href="#B1-materials-17-02568" class="usa-link" aria-describedby="B1-materials-17-02568">1</a>]. Landfills represent the final disposal method for industrial sludge ash (ISA), which is produced during the process of thermal treatment in sludge treatment plants. However, issues that inevitably arise include the high cost of suitable sites and the potential pollution produced during shipping procedures or the landfill itself. These can be mitigated via resourcification of the waste.</p> <p>An adobe brick that is made out of clay has a mass of about 2.2 to 2.5 kg, which drops to 1.7 to 1.8 kg after sintering. It takes 36 tons of clay to make 10,000 bricks. About 340 billion tons of clay are mined annually to produce building bricks globally [<a href="#B2-materials-17-02568" class="usa-link" aria-describedby="B2-materials-17-02568">2</a>,<a href="#B3-materials-17-02568" class="usa-link" aria-describedby="B3-materials-17-02568">3</a>].</p> <p>The main sources of clay in Taiwan are mudstone and shale. In compliance with government policy and the need to lower costs, the current additives are building residues, reservoir and river sediment, ash, and rice husks. However, the yield rate decreases due to the variety of these sources and the problems caused by water content differences in the manufacturing processes [<a href="#B4-materials-17-02568" class="usa-link" aria-describedby="B4-materials-17-02568">4</a>].</p> <p>Much research about utilizing different kinds of waste for making bricks has been published over recent years, which include leather sludge [<a href="#B5-materials-17-02568" class="usa-link" aria-describedby="B5-materials-17-02568">5</a>], water treatment plant sludge [<a href="#B6-materials-17-02568" class="usa-link" aria-describedby="B6-materials-17-02568">6</a>], sewage sludge [<a href="#B7-materials-17-02568" class="usa-link" aria-describedby="B7-materials-17-02568">7</a>], and reservoir sludge [<a href="#B8-materials-17-02568" class="usa-link" aria-describedby="B8-materials-17-02568">8</a>]. These contain common earth elements such as Ca, Si, and Al, and other inorganic compounds, which leads to a high potential for their reuse as materials [<a href="#B9-materials-17-02568" class="usa-link" aria-describedby="B9-materials-17-02568">9</a>].</p> <p>Research has shown that clay could be partially replaced by various kinds of sludge in brick manufacturing and still meet the building criteria in both strength and water absorption rate. However, such research has only focused on the properties of a single type of waste, which does not suit the complexity of industrial sludge. In particular, every batch of sludge might vary due to the sources of sludge treatment received at a manufacturing plant. Therefore, the amount of substitute sludge cannot be the only factor in effectively utilizing industrial sludge as brick material. Extra additives that can modify the properties must be considered to unify the brick quality.</p> <p>Glass, as flux during sintering, decreases the melting point and enhances the quality of the bricks [<a href="#B10-materials-17-02568" class="usa-link" aria-describedby="B10-materials-17-02568">10</a>,<a href="#B11-materials-17-02568" class="usa-link" aria-describedby="B11-materials-17-02568">11</a>,<a href="#B12-materials-17-02568" class="usa-link" aria-describedby="B12-materials-17-02568">12</a>]. Adding glass, rice husk, ash, and marble sludge and replacing 25% of clay with glass increases the compressive strength by 40% [<a href="#B13-materials-17-02568" class="usa-link" aria-describedby="B13-materials-17-02568">13</a>], and this occurs when adding 5~30% of glass into clay samples that contain small amounts of the Zn-plating sludge. As the amount of glass that is added to the specimen increases, the compressive strength increases and the water absorption rate decreases.</p> <p>The increase in brick quality is mainly caused by melting of the glass powder, which forms a dense crystal layer on the surface of the specimen when the sintering temperature reaches 800~900 °C, regardless of the sintering time. This layer prevents liquids from being absorbed by the specimen and, therefore, increases the compressive strength of the specimen [<a href="#B14-materials-17-02568" class="usa-link" aria-describedby="B14-materials-17-02568">14</a>,<a href="#B15-materials-17-02568" class="usa-link" aria-describedby="B15-materials-17-02568">15</a>].</p> <p>There is growing demand for large televisions, mobile devices, and monitors in cars (LCD). Taiwan, as a major LCD manufacturing country, holds 11% of the global exporting market share [<a href="#B16-materials-17-02568" class="usa-link" aria-describedby="B16-materials-17-02568">16</a>]. It produces 8000 tons of waste glass (WG) every year, including 10% of scrape products and 90% of defective products. In addition to being used as recycled building materials after pulverization, landfills are a common final disposal method.</p> <p>This places a heavy burden on the environment, similar to industrial sludge. This study investigates the feasibility of using industrial sludge ash as a substitute for clay in making bricks and evaluates the effect of using waste glass as melting flux on brick quality, aiming to increase the utilization ratio of industrial sludge ash.</p></section><section id="sec2-materials-17-02568"><h2 class="pmc_sec_title">2. Materials and Methods</h2> <section id="sec2dot1-materials-17-02568"><h3 class="pmc_sec_title">2.1. Characterization and Conditioning of Raw Materials</h3> <p>In this research, we used ISA that is the product of thermal treatment (above 800 °C) in a sludge treatment facility. The categories of sludge that are approved for processing include organic sludge (D-0901), inorganic sludge (D-0902), and a sludge mixture (D-0999). The sources of this sludge are from the wastewater treatment industry, dyeing and coating manufacturing industry, microchip manufacturing industry, electronic component manufacturing industry, and other chemical manufacturing industries.</p> <p>The raw material we used was clay bought from a traditional brick factory, and this clay was crushed by a wheel press with its impurities removed. The processed clay was then dried in an oven (105 °C) after basic characteristic analysis. After drying, primary screening (for removal of impurities), crushing, grinding, and sieving (#100), we obtained the dry clay powder for later use. To prevent it from becoming wet, we preserved the clay powder in a sealed plastic bag and dried it in an oven at 105 °C before use. The source of the waste glass (WG) was glass powder from a glass recycling facility. This glass powder was obtained by crushing recycled LCD panels, and the resulting colorless, clear glass powder was then dried and sieved (#100) before being placed in a sealed plastic bag for later use.</p></section><section id="sec2dot2-materials-17-02568"><h3 class="pmc_sec_title">2.2. Preparation of Bricks</h3> <p>Before making adobe brick, the materials were dried, ground, and sieved according to the experimental requirements. This study prepared three pieces of bricks for each mixture proportions. The quantities of materials for making a set of three blocks were calculated. Each 5 cm<sup>3</sup> block took about 250 g of the dried material. The volumes of added water relative to the particle size were 20% and 30% of the weight of the specimen. We poured water into a blender before the other material in case the powder became stuck together and made it more difficult to blend. To increase their viscosity, the blended specimens were left to mature for 24 h.</p> <p>As shown in <a href="#materials-17-02568-f001" class="usa-link">Figure 1</a>, the adobe bricks were compacted to expel the air and increase their density. The specimen was then formed by compression under a pressure of 4 MPa within the mold. The extra material outside the mold was trimmed. We obtained the adobe brick by removing the mold from the compression molding machine and the mold itself. Fewer cracks on the surface of the brick developed if the drying time was prolonged. The air-drying time was set to 48 h in this study. Afterward, the brick was placed into a combustion chamber but only after removing most of the water within the brick. However, it must not be completely dry. Thus, the brick was dried in the oven at 70 °C for 24 h before being placed in the combustion chamber. The sintering parameters in this research refer to common bricks manufacturing procedure from local brick factories. A 36 °C/h rate of temperature change was applied to reach the sintering temperature, which was set at 1000 °C for 1 h. Once the sintering was complete, the specimens were analyzed for various characteristics after they reached room temperature. <a href="#materials-17-02568-t001" class="usa-link">Table 1</a> shows all of the mixture proportions used in this research.</p> <figure class="fig xbox font-sm" id="materials-17-02568-f001"><h4 class="obj_head">Figure 1.</h4> <p class="img-box line-height-none margin-x-neg-2 tablet:margin-x-0 text-center"><a class="tileshop" target="_blank" href="https://www.ncbi.nlm.nih.gov/core/lw/2.0/html/tileshop_pmc/tileshop_pmc_inline.html?title=Click%20on%20image%20to%20zoom&p=PMC3&id=11173697_materials-17-02568-g001.jpg"><img class="graphic zoom-in" src="https://cdn.ncbi.nlm.nih.gov/pmc/blobs/5e38/11173697/733a6df85311/materials-17-02568-g001.jpg" loading="lazy" height="500" width="739" alt="Figure 1"></a></p> <div class="p text-right font-secondary"><a href="figure/materials-17-02568-f001/" class="usa-link" target="_blank" rel="noopener noreferrer">Open in a new tab</a></div> <figcaption><p>The process of brick manufacturing: (<strong>a</strong>) compacting, (<strong>b</strong>) molding, (<strong>c</strong>) demolding, (<strong>d</strong>) drying, (<strong>e</strong>) firing, and (<strong>f</strong>) final product.</p></figcaption></figure><section class="tw xbox font-sm" id="materials-17-02568-t001"><h4 class="obj_head">Table 1.</h4> <div class="caption p"><p>The mixture proportions of each brick sample. WG—waste glass; ISA—industrial sludge waste.</p></div> <div class="tbl-box p" tabindex="0"><table class="content" frame="hsides" rules="groups"> <thead> <tr> <th rowspan="3" align="center" valign="middle" style="border-top:solid thin;border-bottom:solid thin" colspan="1">Brick Samples</th> <th colspan="2" align="center" valign="middle" style="border-top:solid thin;border-bottom:solid thin" rowspan="1">ISA (%)</th> <th colspan="2" align="center" valign="middle" style="border-top:solid thin;border-bottom:solid thin" rowspan="1">WG (%)</th> <th colspan="2" align="center" valign="middle" style="border-top:solid thin;border-bottom:solid thin" rowspan="1">Clay (%)</th> </tr> <tr><th colspan="6" align="center" valign="middle" style="border-bottom:solid thin" rowspan="1">Particle Size</th></tr> <tr> <th align="center" valign="middle" style="border-bottom:solid thin" rowspan="1" colspan="1"><4.75 mm (Raw)</th> <th align="center" valign="middle" style="border-bottom:solid thin" rowspan="1" colspan="1"><0.15 mm</th> <th align="center" valign="middle" style="border-bottom:solid thin" rowspan="1" colspan="1"><4.75 mm (Raw)</th> <th align="center" valign="middle" style="border-bottom:solid thin" rowspan="1" colspan="1"><0.15 mm</th> <th align="center" valign="middle" style="border-bottom:solid thin" rowspan="1" colspan="1"><4.75 mm (Raw)</th> <th align="center" valign="middle" style="border-bottom:solid thin" rowspan="1" colspan="1"><0.15 mm</th> </tr> </thead> <tbody> <tr> <td align="center" valign="middle" rowspan="1" colspan="1">C100</td> <td align="center" valign="middle" rowspan="1" colspan="1">-</td> <td align="center" valign="middle" rowspan="1" colspan="1">-</td> <td align="center" valign="middle" rowspan="1" colspan="1">-</td> <td align="center" valign="middle" rowspan="1" colspan="1">-</td> <td align="center" valign="middle" rowspan="1" colspan="1">100</td> <td align="center" valign="middle" rowspan="1" colspan="1">-</td> </tr> <tr> <td align="center" valign="middle" rowspan="1" colspan="1">RS30RC70</td> <td align="center" valign="middle" rowspan="1" colspan="1">30</td> <td align="center" valign="middle" rowspan="1" colspan="1">-</td> <td align="center" valign="middle" rowspan="1" colspan="1">-</td> <td align="center" valign="middle" rowspan="1" colspan="1">-</td> <td align="center" valign="middle" rowspan="1" colspan="1">70</td> <td align="center" valign="middle" rowspan="1" colspan="1">-</td> </tr> <tr> <td align="center" valign="middle" rowspan="1" colspan="1">RS50RC50</td> <td align="center" valign="middle" rowspan="1" colspan="1">50</td> <td align="center" valign="middle" rowspan="1" colspan="1">-</td> <td align="center" valign="middle" rowspan="1" colspan="1">-</td> <td align="center" valign="middle" rowspan="1" colspan="1">-</td> <td align="center" valign="middle" rowspan="1" colspan="1">50</td> <td align="center" valign="middle" rowspan="1" colspan="1">-</td> </tr> <tr> <td align="center" valign="middle" rowspan="1" colspan="1">S30C70</td> <td align="center" valign="middle" rowspan="1" colspan="1">-</td> <td align="center" valign="middle" rowspan="1" colspan="1">30</td> <td align="center" valign="middle" rowspan="1" colspan="1">-</td> <td align="center" valign="middle" rowspan="1" colspan="1">-</td> <td align="center" valign="middle" rowspan="1" colspan="1">-</td> <td align="center" valign="middle" rowspan="1" colspan="1">70</td> </tr> <tr> <td align="center" valign="middle" rowspan="1" colspan="1">S50C50</td> <td align="center" valign="middle" rowspan="1" colspan="1">-</td> <td align="center" valign="middle" rowspan="1" colspan="1">50</td> <td align="center" valign="middle" rowspan="1" colspan="1">-</td> <td align="center" valign="middle" rowspan="1" colspan="1">-</td> <td align="center" valign="middle" rowspan="1" colspan="1">-</td> <td align="center" valign="middle" rowspan="1" colspan="1">50</td> </tr> <tr> <td align="center" valign="middle" rowspan="1" colspan="1">S50G10C40</td> <td align="center" valign="middle" rowspan="1" colspan="1">-</td> <td align="center" valign="middle" rowspan="1" colspan="1">50</td> <td align="center" valign="middle" rowspan="1" colspan="1">-</td> <td align="center" valign="middle" rowspan="1" colspan="1">10</td> <td align="center" valign="middle" rowspan="1" colspan="1">-</td> <td align="center" valign="middle" rowspan="1" colspan="1">40</td> </tr> <tr> <td align="center" valign="middle" rowspan="1" colspan="1">S50G20C30</td> <td align="center" valign="middle" rowspan="1" colspan="1">-</td> <td align="center" valign="middle" rowspan="1" colspan="1">50</td> <td align="center" valign="middle" rowspan="1" colspan="1">-</td> <td align="center" valign="middle" rowspan="1" colspan="1">20</td> <td align="center" valign="middle" rowspan="1" colspan="1">-</td> <td align="center" valign="middle" rowspan="1" colspan="1">30</td> </tr> <tr> <td align="center" valign="middle" rowspan="1" colspan="1">S50G30C20</td> <td align="center" valign="middle" rowspan="1" colspan="1">-</td> <td align="center" valign="middle" rowspan="1" colspan="1">50</td> <td align="center" valign="middle" rowspan="1" colspan="1">-</td> <td align="center" valign="middle" rowspan="1" colspan="1">30</td> <td align="center" valign="middle" rowspan="1" colspan="1">-</td> <td align="center" valign="middle" rowspan="1" colspan="1">20</td> </tr> <tr> <td align="center" valign="middle" rowspan="1" colspan="1">S50G40C10</td> <td align="center" valign="middle" rowspan="1" colspan="1">-</td> <td align="center" valign="middle" rowspan="1" colspan="1">50</td> <td align="center" valign="middle" rowspan="1" colspan="1">-</td> <td align="center" valign="middle" rowspan="1" colspan="1">40</td> <td align="center" valign="middle" rowspan="1" colspan="1">-</td> <td align="center" valign="middle" rowspan="1" colspan="1">10</td> </tr> <tr> <td align="center" valign="middle" rowspan="1" colspan="1">S50G50C0</td> <td align="center" valign="middle" rowspan="1" colspan="1">-</td> <td align="center" valign="middle" rowspan="1" colspan="1">50</td> <td align="center" valign="middle" rowspan="1" colspan="1">-</td> <td align="center" valign="middle" rowspan="1" colspan="1">50</td> <td align="center" valign="middle" rowspan="1" colspan="1">-</td> <td align="center" valign="middle" rowspan="1" colspan="1">-</td> </tr> <tr> <td align="center" valign="middle" style="border-bottom:solid thin" rowspan="1" colspan="1">S60G40C0</td> <td align="center" valign="middle" style="border-bottom:solid thin" rowspan="1" colspan="1">-</td> <td align="center" valign="middle" style="border-bottom:solid thin" rowspan="1" colspan="1">60</td> <td align="center" valign="middle" style="border-bottom:solid thin" rowspan="1" colspan="1">-</td> <td align="center" valign="middle" style="border-bottom:solid thin" rowspan="1" colspan="1">60</td> <td align="center" valign="middle" style="border-bottom:solid thin" rowspan="1" colspan="1">-</td> <td align="center" valign="middle" style="border-bottom:solid thin" rowspan="1" colspan="1">-</td> </tr> </tbody> </table></div> <div class="p text-right font-secondary"><a href="table/materials-17-02568-t001/" class="usa-link" target="_blank" rel="noopener noreferrer">Open in a new tab</a></div></section><p>For the control group (C100), 100% of clay was used. Unprocessed ISA (RS) (particle size < 4.75 mm) was used to replace 30 and 50% of clay to make RS30RC70 and RS50RC50 specimens for the first analysis, respectively. In the second analysis, we used processed materials (ground and sieved) (particle size < 0.15 mm) to replace 30 and 50% of clay to make S30C70 and S50C50 specimens, respectively. For the third analysis, 10, 20, 30, 40, and 50% of clay were replaced by WG, while the other 50% of clay was still replaced by processed materials similar to the second analysis to determine the effects on the quality of brick when using waste glass as flux.</p></section><section id="sec2dot3-materials-17-02568"><h3 class="pmc_sec_title">2.3. Testing Procedure</h3> <p>In this study, the characteristic analysis included the compressive strength, water absorption rate, fire shrinkage coefficient, and weight loss on ignition. The test method for compressive strength refers to the [<a href="#B17-materials-17-02568" class="usa-link" aria-describedby="B17-materials-17-02568">17</a>] National Standards of the Republic of China (CNS). CNS 382 is specific about the specification of common bricks.</p> <p>The area (<em>A</em>) of the compressed surface was obtained by measuring the length and width of the specimen. Due to the uneven surface of the brick, a piece of thick paper was placed on both the top and bottom of the brick to more evenly distribute the applied compression on the brick. We increased the compressive stress by 0.5~1 MPa per second until the specimen was damaged, at which point we recorded the maximum weight (<em>W</em>) applied (HT-9501 Hydraulic Servo Universal Testing Machine. Hung Ta instrument GO.LTD, Taiwan). We obtained the compressive strength by substituting the value of area (<em>A</em>) and weight (<em>W</em>) into Equation (1):</p> <table class="disp-formula p" id="FD1-materials-17-02568"><tr> <td class="formula"><math id="mm1" display="block" overflow="linebreak"><mrow><mrow><mi>C</mi><mo>=</mo><mfrac><mi>W</mi><mi>A</mi></mfrac></mrow></mrow></math></td> <td class="label">(1)</td> </tr></table> <p> where <em>C</em> is the compressive strength (MPa), <em>W</em> is the maximum weight (N) applied, and <em>A</em> is the area of the compressed surface (mm<sup>2</sup>).</p> <p>Brick water absorption was determined by the method according to regulation CNS 382. After finishing the sintering process in the combustion chamber, we let the specimen cool to room temperature. The weight of the brick (<em>m</em><sub>1</sub>) was obtained by using an electronic scale (FX-3000GD.A&D COMPANY, LIMITED, Tokyo, Japan). The brick was then placed in clean water at 25 °C for 24 h. After 24 h, we removed the extra water remaining on the surface of the brick with a damp cloth. The saturated surface-dry weight (<em>m</em><sub>2</sub>) was then obtained by again using the electronic scale again. According to Equation (2), we obtained the water absorption ratio of the brick as follows:</p> <table class="disp-formula p" id="FD2-materials-17-02568"><tr> <td class="formula"><math id="mm2" display="block" overflow="linebreak"><mrow><mrow><mrow><mo> </mo><mi>absorption</mi><mo> </mo></mrow><mo>=</mo><mfrac><mrow><msub><mi>m</mi><mn>2</mn></msub><mo>−</mo><msub><mi>m</mi><mn>1</mn></msub></mrow><mrow><msub><mi>m</mi><mn>1</mn></msub></mrow></mfrac><mo>×</mo><mn>100</mn><mo>%</mo></mrow></mrow></math></td> <td class="label">(2)</td> </tr></table> <p> where <span xmlns:mml="http://www.w3.org/1998/Math/MathML"><math id="mm3" overflow="linebreak"><mrow><mrow><msub><mi>m</mi><mn>1</mn></msub><mrow><mo> </mo><mi>is</mi><mo> </mo><mi>the</mi><mo> </mo><mi>dry</mi><mo> </mo><mi>weight</mi><mo> </mo></mrow><mrow><mo>(</mo><mi mathvariant="normal">g</mi><mo>)</mo></mrow></mrow></mrow></math></span> and <span xmlns:mml="http://www.w3.org/1998/Math/MathML"><math id="mm4" overflow="linebreak"><mrow><mrow><msub><mi>m</mi><mn>2</mn></msub></mrow></mrow></math></span> is the saturated surface-dry weight (g).</p> <p>The adobe bricks formed after compaction were air-dried for 48 h using an electronic fan and then placed in an oven at 70 °C for 24 h. After all the drying processes, the weight of the adobe brick (<em>m<sub>dry</sub></em>) was obtained using the electronic scale. Then, the bricks were placed into the combustion chamber for sintering, after which the bricks were cooled to room temperature and again weighed (<em>m<sub>sin</sub></em>). We obtained the weight loss on ignition using Equation (3):</p> <table class="disp-formula p" id="FD3-materials-17-02568"><tr> <td class="formula"><math id="mm5" display="block" overflow="linebreak"><mrow><mrow><mrow><mi>weight</mi><mo> </mo><mi>loss</mi><mo> </mo><mi>on</mi><mo> </mo><mi>ignition</mi></mrow><mo>=</mo><mfrac><mrow><msub><mi>m</mi><mrow><mi>d</mi><mi>r</mi><mi>y</mi></mrow></msub><mo>−</mo><msub><mi>m</mi><mrow><mi>s</mi><mi>i</mi><mi>n</mi></mrow></msub></mrow><mrow><msub><mi>m</mi><mrow><mi>s</mi><mi>i</mi><mi>n</mi></mrow></msub></mrow></mfrac><mo>×</mo><mn>100</mn><mo>%</mo></mrow></mrow></math></td> <td class="label">(3)</td> </tr></table> <p> where <span xmlns:mml="http://www.w3.org/1998/Math/MathML"><math id="mm6" overflow="linebreak"><mrow><mrow><msub><mi>m</mi><mrow><mi>d</mi><mi>r</mi><mi>y</mi></mrow></msub></mrow></mrow></math></span> is the weight of dried brick (g) and <span xmlns:mml="http://www.w3.org/1998/Math/MathML"><math id="mm7" overflow="linebreak"><mrow><mrow><msub><mi>m</mi><mrow><mi>s</mi><mi>i</mi><mi>n</mi></mrow></msub><mrow><mo> </mo><mi>is</mi><mo> </mo><mi>the</mi><mo> </mo><mi>weight</mi><mo> </mo><mi>of</mi><mo> </mo><mi>sin</mi><mi>tered</mi><mo> </mo><mi>brick</mi></mrow></mrow></mrow></math></span> (g).</p> <p>The brick firing shrinkage test refers to [<a href="#B18-materials-17-02568" class="usa-link" aria-describedby="B18-materials-17-02568">18</a>]. ASTM C67-14 [<a href="#B19-materials-17-02568" class="usa-link" aria-describedby="B19-materials-17-02568">19</a>] specifically is about standard test methods for sampling and testing brick and structural clay tile. We obtained the volume of the adobe brick by measuring the length, width, and height of the dry brick (<em>V<sub>dry</sub></em>). After the sintering process, we obtained the sintered volume (<em>V<sub>sin</sub></em>) using the same method. The brick firing shrinkage ratio was then obtained according to Equation (4):</p> <table class="disp-formula p" id="FD4-materials-17-02568"><tr> <td class="formula"><math id="mm8" display="block" overflow="linebreak"><mrow><mrow><mrow><mi>firing</mi><mo> </mo><mi>shrinkage</mi></mrow><mo>=</mo><mfrac><mrow><msub><mi>V</mi><mrow><mi>d</mi><mi>r</mi><mi>y</mi></mrow></msub><mo>−</mo><msub><mi>V</mi><mrow><mi>s</mi><mi>i</mi><mi>n</mi></mrow></msub></mrow><mrow><msub><mi>V</mi><mrow><mi>s</mi><mi>i</mi><mi>n</mi></mrow></msub></mrow></mfrac><mo>×</mo><mn>100</mn></mrow></mrow></math></td> <td class="label">(4)</td> </tr></table> <p> where <span xmlns:mml="http://www.w3.org/1998/Math/MathML"><math id="mm9" overflow="linebreak"><mrow><mrow><msub><mi>V</mi><mrow><mi>d</mi><mi>r</mi><mi>y</mi></mrow></msub></mrow></mrow></math></span> is the volume of the dry adobe brick (cm<sup>3</sup>) and <span xmlns:mml="http://www.w3.org/1998/Math/MathML"><math id="mm10" overflow="linebreak"><mrow><mrow><msub><mi>V</mi><mrow><mi>s</mi><mi>i</mi><mi>n</mi></mrow></msub></mrow></mrow></math></span> is the volume of the sintered brick (cm<sup>3</sup>).</p> <p>First, we measured the weight of the sieved ISA before drying (<em>W</em><sub>1</sub>). Then, we measured it again after it was dried in an oven at 105 °C for 24 h (<em>W</em><sub>2</sub>). The oven-dried ISA was then put into the combustion chamber at 800 °C for 3 h. After the combustion chamber, the ISA was measured again after cooling down to room temperature (<em>W</em><sub>3</sub>). </p> <table class="disp-formula p" id="FD5-materials-17-02568"><tr> <td class="formula"><math id="mm11" display="block" overflow="linebreak"><mrow><mrow><mrow><mi>water</mi><mo> </mo><mi>content</mi></mrow><mo>=</mo><mfrac><mrow><msub><mi>W</mi><mn>1</mn></msub><mo>−</mo><msub><mi>W</mi><mn>2</mn></msub></mrow><mrow><msub><mi>W</mi><mn>1</mn></msub></mrow></mfrac><mo>×</mo><mn>100</mn></mrow></mrow></math></td> <td class="label">(5)</td> </tr></table> <table class="disp-formula p" id="FD6-materials-17-02568"><tr> <td class="formula"><math id="mm12" display="block" overflow="linebreak"><mrow><mrow><mrow><mi>ash</mi><mo> </mo><mi>content</mi></mrow><mo>=</mo><mfrac><mrow><msub><mi>W</mi><mn>3</mn></msub></mrow><mrow><msub><mi>W</mi><mn>1</mn></msub></mrow></mfrac><mo>×</mo><mn>100</mn></mrow></mrow></math></td> <td class="label">(6)</td> </tr></table> <table class="disp-formula p" id="FD7-materials-17-02568"><tr> <td class="formula"><math id="mm13" display="block" overflow="linebreak"><mrow><mrow><mi>combustibility</mi><mo>=</mo><mn>100</mn><mo>%</mo><mo>−</mo><mrow><mi>water</mi><mo> </mo><mi>content</mi><mo> </mo></mrow><mrow><mo>(</mo><mo>%</mo><mo>)</mo></mrow><mo>−</mo><mrow><mi>ash</mi><mo> </mo><mi>content</mi><mo> </mo></mrow><mrow><mo>(</mo><mo>%</mo><mo>)</mo></mrow></mrow></mrow></math></td> <td class="label">(7)</td> </tr></table> <p> where <span xmlns:mml="http://www.w3.org/1998/Math/MathML"><math id="mm14" overflow="linebreak"><mrow><mrow><msub><mi>W</mi><mn>1</mn></msub></mrow></mrow></math></span> is the weight of the undried ISA, <span xmlns:mml="http://www.w3.org/1998/Math/MathML"><math id="mm15" overflow="linebreak"><mrow><mi>W</mi></mrow></math></span><sub>2</sub> is the weight of the dried ISA, and <em>W</em><sub>3</sub> is the weight of combusted ISA.</p></section></section><section id="sec3-materials-17-02568"><h2 class="pmc_sec_title">3. Results and Discussion</h2> <section id="sec3dot1-materials-17-02568"><h3 class="pmc_sec_title">3.1. Characterization of Raw Materials Used for Brick Manufacturing</h3> <p>To understand the relationship between the characteristics of raw materials and sintering behaviors, we conducted XRD and XRF analysis on the ISA, WG, and clay used in the bricks. The chemical composition and basic properties of each material are shown in <a href="#materials-17-02568-t002" class="usa-link">Table 2</a>.</p> <section class="tw xbox font-sm" id="materials-17-02568-t002"><h4 class="obj_head">Table 2.</h4> <div class="caption p"><p>Chemical composition and other properties of the raw materials.</p></div> <div class="tbl-box p" tabindex="0"><table class="content" frame="hsides" rules="groups"> <thead><tr> <th align="center" valign="middle" style="border-top:solid thin;border-bottom:solid thin" rowspan="1" colspan="1">Properties</th> <th align="center" valign="middle" style="border-top:solid thin;border-bottom:solid thin" rowspan="1" colspan="1">ISA</th> <th align="center" valign="middle" style="border-top:solid thin;border-bottom:solid thin" rowspan="1" colspan="1">WG</th> <th align="center" valign="middle" style="border-top:solid thin;border-bottom:solid thin" rowspan="1" colspan="1">Clay</th> </tr></thead> <tbody> <tr> <td align="center" valign="middle" rowspan="1" colspan="1">SiO<sub>2</sub> (%)</td> <td align="center" valign="middle" rowspan="1" colspan="1">41.80</td> <td align="center" valign="middle" rowspan="1" colspan="1">63.91</td> <td align="center" valign="middle" rowspan="1" colspan="1">60.72</td> </tr> <tr> <td align="center" valign="middle" rowspan="1" colspan="1">Al<sub>2</sub>O<sub>3</sub> (%)</td> <td align="center" valign="middle" rowspan="1" colspan="1">8.69</td> <td align="center" valign="middle" rowspan="1" colspan="1">16.44</td> <td align="center" valign="middle" rowspan="1" colspan="1">20.55</td> </tr> <tr> <td align="center" valign="middle" rowspan="1" colspan="1">Fe<sub>2</sub>O<sub>3</sub> (%)</td> <td align="center" valign="middle" rowspan="1" colspan="1">7.67</td> <td align="center" valign="middle" rowspan="1" colspan="1">0.29</td> <td align="center" valign="middle" rowspan="1" colspan="1">9.62</td> </tr> <tr> <td align="center" valign="middle" rowspan="1" colspan="1">CaO (%)</td> <td align="center" valign="middle" rowspan="1" colspan="1">31.31</td> <td align="center" valign="middle" rowspan="1" colspan="1">9.57</td> <td align="center" valign="middle" rowspan="1" colspan="1">0.84</td> </tr> <tr> <td align="center" valign="middle" rowspan="1" colspan="1">P<sub>2</sub>O<sub>5</sub> (%)</td> <td align="center" valign="middle" rowspan="1" colspan="1">13.58</td> <td align="center" valign="middle" rowspan="1" colspan="1">-</td> <td align="center" valign="middle" rowspan="1" colspan="1">-</td> </tr> <tr> <td align="center" valign="middle" rowspan="1" colspan="1">SO<sub>3</sub> (%)</td> <td align="center" valign="middle" rowspan="1" colspan="1">3.58</td> <td align="center" valign="middle" rowspan="1" colspan="1">-</td> <td align="center" valign="middle" rowspan="1" colspan="1">-</td> </tr> <tr> <td align="center" valign="middle" rowspan="1" colspan="1">ZnO (%)</td> <td align="center" valign="middle" rowspan="1" colspan="1">0.37</td> <td align="center" valign="middle" rowspan="1" colspan="1">0.23</td> <td align="center" valign="middle" rowspan="1" colspan="1">-</td> </tr> <tr> <td align="center" valign="middle" rowspan="1" colspan="1">Cr<sub>2</sub>O<sub>3</sub> (%)</td> <td align="center" valign="middle" rowspan="1" colspan="1">0.15</td> <td align="center" valign="middle" rowspan="1" colspan="1">-</td> <td align="center" valign="middle" rowspan="1" colspan="1">-</td> </tr> <tr> <td align="center" valign="middle" rowspan="1" colspan="1">NiO (%)</td> <td align="center" valign="middle" rowspan="1" colspan="1">0.13</td> <td align="center" valign="middle" rowspan="1" colspan="1">-</td> <td align="center" valign="middle" rowspan="1" colspan="1">-</td> </tr> <tr> <td align="center" valign="middle" rowspan="1" colspan="1">K<sub>2</sub>O (%)</td> <td align="center" valign="middle" rowspan="1" colspan="1">0.97</td> <td align="center" valign="middle" rowspan="1" colspan="1">-</td> <td align="center" valign="middle" rowspan="1" colspan="1">5.29</td> </tr> <tr> <td align="center" valign="middle" rowspan="1" colspan="1">MnO<sub>2</sub> (%)</td> <td align="center" valign="middle" rowspan="1" colspan="1">-</td> <td align="center" valign="middle" rowspan="1" colspan="1">-</td> <td align="center" valign="middle" rowspan="1" colspan="1">0.16</td> </tr> <tr> <td align="center" valign="middle" rowspan="1" colspan="1">CuO (%)</td> <td align="center" valign="middle" rowspan="1" colspan="1">0.38</td> <td align="center" valign="middle" rowspan="1" colspan="1">-</td> <td align="center" valign="middle" rowspan="1" colspan="1">-</td> </tr> <tr> <td align="center" valign="middle" rowspan="1" colspan="1">TiO<sub>2</sub> (%)</td> <td align="center" valign="middle" rowspan="1" colspan="1">0.34</td> <td align="center" valign="middle" rowspan="1" colspan="1">0.17</td> <td align="center" valign="middle" rowspan="1" colspan="1">1.34</td> </tr> <tr> <td align="center" valign="middle" rowspan="1" colspan="1">Specific gravity</td> <td align="center" valign="middle" rowspan="1" colspan="1">2.28</td> <td align="center" valign="middle" rowspan="1" colspan="1">2.51</td> <td align="center" valign="middle" rowspan="1" colspan="1">2.47</td> </tr> <tr> <td align="center" valign="middle" rowspan="1" colspan="1">Water content (%)</td> <td align="center" valign="middle" rowspan="1" colspan="1">1.64</td> <td align="center" valign="middle" rowspan="1" colspan="1">-</td> <td align="center" valign="middle" rowspan="1" colspan="1">1.89</td> </tr> <tr> <td align="center" valign="middle" rowspan="1" colspan="1">Absorption (%)</td> <td align="center" valign="middle" rowspan="1" colspan="1">23.54</td> <td align="center" valign="middle" rowspan="1" colspan="1">-</td> <td align="center" valign="middle" rowspan="1" colspan="1">11.35</td> </tr> <tr> <td align="center" valign="middle" style="border-bottom:solid thin" rowspan="1" colspan="1">Combustibility (%)</td> <td align="center" valign="middle" style="border-bottom:solid thin" rowspan="1" colspan="1">3.24</td> <td align="center" valign="middle" style="border-bottom:solid thin" rowspan="1" colspan="1">-</td> <td align="center" valign="middle" style="border-bottom:solid thin" rowspan="1" colspan="1">5.38</td> </tr> </tbody> </table></div> <div class="p text-right font-secondary"><a href="table/materials-17-02568-t002/" class="usa-link" target="_blank" rel="noopener noreferrer">Open in a new tab</a></div></section><p>According to XRF analysis, ISA contains up to 31.31% of calcium due to the manufacturing process. The content of silicon, aluminum, and ferrum were similar to that of clay and WG, but only that of silicon was too low for use as a sintering material. Skrifvars et al. (1994) [<a href="#B20-materials-17-02568" class="usa-link" aria-describedby="B20-materials-17-02568">20</a>] investigated the sintering mechanism of solid particles using coal-burning ashes from five different sources. The result indicates that silicon can easily form liquid viscous flow from 800 to 900 °C, which enhances the effect of viscous flow in sintering mechanics. At 985 °C, 79.7% of the melted mass was SiO<sub>2</sub>, which indicates that SiO<sub>2</sub> is easily liquefied within this temperature range. Thus, the viscous flow would be the major sintering mechanism if the material contained a high level of silicon. The composition of clay, from which bricks are commonly manufactured, is mainly SiO<sub>2</sub>, Al<sub>2</sub>O<sub>3</sub>, Fe<sub>2</sub>O<sub>3</sub>, and incorporated water. Clay consists of 50~70% SiO<sub>2.</sub> <a href="#materials-17-02568-f002" class="usa-link">Figure 2</a> shows that the silicon within ISA is mainly in a crystalline form of SiO<sub>2</sub>, according to XRD, which is similar to clay. However, the material in glass manufacturing would be melted first and then rapidly cooled, causing the molecules to not be in crystalline form. Thus, there would be no significant peaks shown on the XRD spectrum.</p> <figure class="fig xbox font-sm" id="materials-17-02568-f002"><h4 class="obj_head">Figure 2.</h4> <p class="img-box line-height-none margin-x-neg-2 tablet:margin-x-0 text-center"><a class="tileshop" target="_blank" href="https://www.ncbi.nlm.nih.gov/core/lw/2.0/html/tileshop_pmc/tileshop_pmc_inline.html?title=Click%20on%20image%20to%20zoom&p=PMC3&id=11173697_materials-17-02568-g002a.jpg"><img class="graphic zoom-in" src="https://cdn.ncbi.nlm.nih.gov/pmc/blobs/5e38/11173697/c7e20ba98edc/materials-17-02568-g002a.jpg" loading="lazy" height="454" width="779" alt="Figure 2"></a></p> <p class="img-box line-height-none margin-x-neg-2 tablet:margin-x-0 text-center"><a class="tileshop" target="_blank" href="https://www.ncbi.nlm.nih.gov/core/lw/2.0/html/tileshop_pmc/tileshop_pmc_inline.html?title=Click%20on%20image%20to%20zoom&p=PMC3&id=11173697_materials-17-02568-g002b.jpg"><img class="graphic zoom-in" src="https://cdn.ncbi.nlm.nih.gov/pmc/blobs/5e38/11173697/1b441ebc0878/materials-17-02568-g002b.jpg" loading="lazy" height="993" width="789" alt="Figure 2"></a></p> <div class="p text-right font-secondary"><a href="figure/materials-17-02568-f002/" class="usa-link" target="_blank" rel="noopener noreferrer">Open in a new tab</a></div> <figcaption><p>XRD data: (<strong>a</strong>) ISA; (<strong>b</strong>) WG; (<strong>c</strong>) clay.</p></figcaption></figure></section><section id="sec3dot2-materials-17-02568"><h3 class="pmc_sec_title">3.2. Effects of Industrial Sludge Ash Content on Brick</h3> <p>According to the CNS 382 building brick specification, bricks are separated into first-, second-, and third-class bricks. Their compressive strengths exceed 30, 20, and 15 MPa, respectively, and their water absorption ratios are under 10, 13, and 15%, respectively. The comparison between replacing 30% and 50% of clay with unprocessed ISA in brick making and 100% clay brick is shown in <a href="#materials-17-02568-f003" class="usa-link">Figure 3</a>. The compressive strength of all clay brick is 44 MPa, which is therefore first-class brick. Replacing 30% of clay with unprocessed ISA decreases the compressive strength to the second-class brick standard. Replacing 50% of clay with unprocessed ISA drops the compressive strength to below the criterion of third-class brick.</p> <figure class="fig xbox font-sm" id="materials-17-02568-f003"><h4 class="obj_head">Figure 3.</h4> <p class="img-box line-height-none margin-x-neg-2 tablet:margin-x-0 text-center"><a class="tileshop" target="_blank" href="https://www.ncbi.nlm.nih.gov/core/lw/2.0/html/tileshop_pmc/tileshop_pmc_inline.html?title=Click%20on%20image%20to%20zoom&p=PMC3&id=11173697_materials-17-02568-g003.jpg"><img class="graphic zoom-in" src="https://cdn.ncbi.nlm.nih.gov/pmc/blobs/5e38/11173697/85faa16ac2e8/materials-17-02568-g003.jpg" loading="lazy" height="337" width="779" alt="Figure 3"></a></p> <div class="p text-right font-secondary"><a href="figure/materials-17-02568-f003/" class="usa-link" target="_blank" rel="noopener noreferrer">Open in a new tab</a></div> <figcaption><p>Effect of different unprocessed ISA contents on the water absorption and compressive strength of specimens.</p></figcaption></figure><p>The water absorption ratio of all clay brick made according to the method in our study reached the first-class brick standard. Replacing 30% of clay with unprocessed ISA led to a water absorption ratio matching that of the second-class brick standard, and replacing 50% of clay with unprocessed ISA made the water absorption ratio 24.1%, which failed to pass the lowest standard.</p></section><section id="sec3dot3-materials-17-02568"><h3 class="pmc_sec_title">3.3. Process Improvement</h3> <p>The compressive strength and water absorption ratio rapidly deteriorate as the particle size is increased. Therefore, we investigated how the particle size affects the quality of the bricks. We sieved the clay and ISA using a #100 screen (<0.15 mm). Applying the same method from the previous experiment, we replaced 30 and 50% of clay with fine ISA material. The results are shown in <a href="#materials-17-02568-f004" class="usa-link">Figure 4</a> and <a href="#materials-17-02568-f005" class="usa-link">Figure 5</a>. The compressive strength was increased by 28% while using 100% of refined clay. The compressive strength was increased by 32% with 30% of refined ISA replacement. The compressive strength failed to meet any standard with 50% of refined ISA replacement. But the compressive strength was increased by 22% compared to using unprocessed ISA as replacement. The water absorption ratio was slightly more significant. Using 30% and 50% of refined ISA replacement, the water absorption ratio decreased by about 1.5% and 3.6%, respectively. <a href="#materials-17-02568-f006" class="usa-link">Figure 6</a> shows that the cross-section of brick using the screened material was smoother and denser and with no obvious holes. The reduction in the particle size enhanced the sintering result, resulting in faster densification. The variety of particle sizes also affected the result. A wide variety of particle sizes might increase the density of the adobe bricks, as well as the distribution of the hole sizes. Therefore, the reduction in particle sizes causes a low sintering density. Thus, selecting a narrow range of particle sizes increases the sintering density.</p> <figure class="fig xbox font-sm" id="materials-17-02568-f004"><h4 class="obj_head">Figure 4.</h4> <p class="img-box line-height-none margin-x-neg-2 tablet:margin-x-0 text-center"><a class="tileshop" target="_blank" href="https://www.ncbi.nlm.nih.gov/core/lw/2.0/html/tileshop_pmc/tileshop_pmc_inline.html?title=Click%20on%20image%20to%20zoom&p=PMC3&id=11173697_materials-17-02568-g004.jpg"><img class="graphic zoom-in" src="https://cdn.ncbi.nlm.nih.gov/pmc/blobs/5e38/11173697/0dd109445809/materials-17-02568-g004.jpg" loading="lazy" height="323" width="793" alt="Figure 4"></a></p> <div class="p text-right font-secondary"><a href="figure/materials-17-02568-f004/" class="usa-link" target="_blank" rel="noopener noreferrer">Open in a new tab</a></div> <figcaption><p>Effect of sieved ISA with different particle sizes on the compressive strength of specimens.</p></figcaption></figure><figure class="fig xbox font-sm" id="materials-17-02568-f005"><h4 class="obj_head">Figure 5.</h4> <p class="img-box line-height-none margin-x-neg-2 tablet:margin-x-0 text-center"><a class="tileshop" target="_blank" href="https://www.ncbi.nlm.nih.gov/core/lw/2.0/html/tileshop_pmc/tileshop_pmc_inline.html?title=Click%20on%20image%20to%20zoom&p=PMC3&id=11173697_materials-17-02568-g005.jpg"><img class="graphic zoom-in" src="https://cdn.ncbi.nlm.nih.gov/pmc/blobs/5e38/11173697/a9df5176d70f/materials-17-02568-g005.jpg" loading="lazy" height="358" width="747" alt="Figure 5"></a></p> <div class="p text-right font-secondary"><a href="figure/materials-17-02568-f005/" class="usa-link" target="_blank" rel="noopener noreferrer">Open in a new tab</a></div> <figcaption><p>Effect of sieved ISA with different particle sizes on the water absorption of specimens.</p></figcaption></figure><figure class="fig xbox font-sm" id="materials-17-02568-f006"><h4 class="obj_head">Figure 6.</h4> <p class="img-box line-height-none margin-x-neg-2 tablet:margin-x-0 text-center"><a class="tileshop" target="_blank" href="https://www.ncbi.nlm.nih.gov/core/lw/2.0/html/tileshop_pmc/tileshop_pmc_inline.html?title=Click%20on%20image%20to%20zoom&p=PMC3&id=11173697_materials-17-02568-g006.jpg"><img class="graphic zoom-in" src="https://cdn.ncbi.nlm.nih.gov/pmc/blobs/5e38/11173697/535b24687890/materials-17-02568-g006.jpg" loading="lazy" height="297" width="777" alt="Figure 6"></a></p> <div class="p text-right font-secondary"><a href="figure/materials-17-02568-f006/" class="usa-link" target="_blank" rel="noopener noreferrer">Open in a new tab</a></div> <figcaption><p>Cross-section images of bricks: (<strong>a</strong>) S30C70; (<strong>b</strong>) RS30RC70.</p></figcaption></figure></section><section id="sec3dot4-materials-17-02568"><h3 class="pmc_sec_title">3.4. Effects of Fluxing Agents on Properties of Brick</h3> <p>According to <a href="#materials-17-02568-f007" class="usa-link">Figure 7</a>, while adding 10~20% of WG did not affect the compressive strength much, which was about 8~9 MPa, adding 30% of WG significantly increased this strength up to 14~15 MPa. Parts of the specimens met the third-class criterion. While the amount of WG added increased between 40% and ≈50%, the compressive strength increased. We obtained the best compressive strength when we completely replaced all clay with WG. The strength attained the second-class brick standard of 20 MPa. However, if the ratio of the ISA added passed 50% to 60%, the compressive strength dropped to 11 MPa, which is similar to the case of adding 10~20% of WG.</p> <figure class="fig xbox font-sm" id="materials-17-02568-f007"><h4 class="obj_head">Figure 7.</h4> <p class="img-box line-height-none margin-x-neg-2 tablet:margin-x-0 text-center"><a class="tileshop" target="_blank" href="https://www.ncbi.nlm.nih.gov/core/lw/2.0/html/tileshop_pmc/tileshop_pmc_inline.html?title=Click%20on%20image%20to%20zoom&p=PMC3&id=11173697_materials-17-02568-g007.jpg"><img class="graphic zoom-in" src="https://cdn.ncbi.nlm.nih.gov/pmc/blobs/5e38/11173697/ad5ef753cfdc/materials-17-02568-g007.jpg" loading="lazy" height="426" width="744" alt="Figure 7"></a></p> <div class="p text-right font-secondary"><a href="figure/materials-17-02568-f007/" class="usa-link" target="_blank" rel="noopener noreferrer">Open in a new tab</a></div> <figcaption><p>Effect of different WG contents on the compressive strength of specimens.</p></figcaption></figure><p>As WG does not have a fixed melting temperature, unlike crystalline materials, the atomic permutation of glass is more similar to that of a liquid (short-range order) [<a href="#B21-materials-17-02568" class="usa-link" aria-describedby="B21-materials-17-02568">21</a>] than a crystal (long-range order). Therefore, adding glass makes the specimens melt easier than the crystalline clay. Under the high-temperature sintering process, glass molecules are melted and densified together with the clay molecules, filling the gap between the sintered objects and enhancing the compressive strength of the bricks [<a href="#B22-materials-17-02568" class="usa-link" aria-describedby="B22-materials-17-02568">22</a>]. The increase in compressive strength should indicate a decrease in water absorption. As shown in <a href="#materials-17-02568-f008" class="usa-link">Figure 8</a>, the water absorption ratio decreased as more WG was added. When the WG replacement was 50%, the water absorption ratio met the second-class brick standard. However, the water absorption of specimen S60G40 (60% ISA) increased to 18% instead, as with the reverse situation of compressive strength.</p> <figure class="fig xbox font-sm" id="materials-17-02568-f008"><h4 class="obj_head">Figure 8.</h4> <p class="img-box line-height-none margin-x-neg-2 tablet:margin-x-0 text-center"><a class="tileshop" target="_blank" href="https://www.ncbi.nlm.nih.gov/core/lw/2.0/html/tileshop_pmc/tileshop_pmc_inline.html?title=Click%20on%20image%20to%20zoom&p=PMC3&id=11173697_materials-17-02568-g008.jpg"><img class="graphic zoom-in" src="https://cdn.ncbi.nlm.nih.gov/pmc/blobs/5e38/11173697/8f8d6729fde5/materials-17-02568-g008.jpg" loading="lazy" height="293" width="727" alt="Figure 8"></a></p> <div class="p text-right font-secondary"><a href="figure/materials-17-02568-f008/" class="usa-link" target="_blank" rel="noopener noreferrer">Open in a new tab</a></div> <figcaption><p>Effect of different WG contents on water absorption of specimens.</p></figcaption></figure><p>WG had a significant effect on the volume (<a href="#materials-17-02568-f009" class="usa-link">Figure 9</a>). With 10~50% of clay replaced by WG, the brick firing shrinkage increased from 15 to 23%. Specimen S60G40, however, did not exhibit the reverse situation as with compressive strength and water absorption ratio. The firing shrinkage still increased. This means that the firing shrinkage was affected by some substances within ISA besides the WG. The study by Park (2003) [<a href="#B23-materials-17-02568" class="usa-link" aria-describedby="B23-materials-17-02568">23</a>] indicated that adding 10% of CaO to sewage sludge will decrease the melting point. With the involvement of CaO, the crystalline phase of anorthite and diopside increases, and its crystalline phase enhances the hardness of the ceramic glass. Reich (2003) [<a href="#B24-materials-17-02568" class="usa-link" aria-describedby="B24-materials-17-02568">24</a>] indicated that there will be a substitution reaction between heavy metal and CaO. Adding different amounts of CaO will form different metal compounds, leading to different melting properties. Due to the bonds within crystal lattices, the melting point decreases. According to this research that indicates that CaO is considered as flux, we suggest that the CaO facilitates the WG to reach the melting phase. However, there is no solid proof of its effects on firing shrinkage.</p> <figure class="fig xbox font-sm" id="materials-17-02568-f009"><h4 class="obj_head">Figure 9.</h4> <p class="img-box line-height-none margin-x-neg-2 tablet:margin-x-0 text-center"><a class="tileshop" target="_blank" href="https://www.ncbi.nlm.nih.gov/core/lw/2.0/html/tileshop_pmc/tileshop_pmc_inline.html?title=Click%20on%20image%20to%20zoom&p=PMC3&id=11173697_materials-17-02568-g009.jpg"><img class="graphic zoom-in" src="https://cdn.ncbi.nlm.nih.gov/pmc/blobs/5e38/11173697/ac60f986b453/materials-17-02568-g009.jpg" loading="lazy" height="410" width="752" alt="Figure 9"></a></p> <div class="p text-right font-secondary"><a href="figure/materials-17-02568-f009/" class="usa-link" target="_blank" rel="noopener noreferrer">Open in a new tab</a></div> <figcaption><p>Effect of different WG contents on volume shrinkage of the specimens.</p></figcaption></figure><p>The weight loss on ignition means the weight difference before and after sintering. The amount of loss depends on the evaporation of water, decomposition of organic compounds, disintegration and evaporation of inorganic salts, and minor heavy metal escape under high temperature. The effects of adding WG are shown in <a href="#materials-17-02568-f010" class="usa-link">Figure 10</a>. It was clearly affected by the contents of ISA and clay. WG is an inorganic salt, meaning that the weight loss on ignition mainly depends on the contents of ISA and clay. Specimen S50G50 had the most glass among all specimens. Therefore, its loss on ignition was the least at approximately 4.2%. Normally, if the specimens contain a high concentration of organic compounds or inorganic salts that decompose easily under high temperature, the loss of those components will create air holes following decomposition. The air holes compromise the inner structure of the specimens, affecting the characteristics such as the compressive strength and water absorption ratio. This result indicates that weight loss on ignition does relate to the compressive strength and water absorption ratio.</p> <figure class="fig xbox font-sm" id="materials-17-02568-f010"><h4 class="obj_head">Figure 10.</h4> <p class="img-box line-height-none margin-x-neg-2 tablet:margin-x-0 text-center"><a class="tileshop" target="_blank" href="https://www.ncbi.nlm.nih.gov/core/lw/2.0/html/tileshop_pmc/tileshop_pmc_inline.html?title=Click%20on%20image%20to%20zoom&p=PMC3&id=11173697_materials-17-02568-g010.jpg"><img class="graphic zoom-in" src="https://cdn.ncbi.nlm.nih.gov/pmc/blobs/5e38/11173697/1add4841d470/materials-17-02568-g010.jpg" loading="lazy" height="437" width="758" alt="Figure 10"></a></p> <div class="p text-right font-secondary"><a href="figure/materials-17-02568-f010/" class="usa-link" target="_blank" rel="noopener noreferrer">Open in a new tab</a></div> <figcaption><p>Effect of different WG contents in specimens on the loss of ignition.</p></figcaption></figure></section></section><section id="sec4-materials-17-02568"><h2 class="pmc_sec_title">4. Conclusions</h2> <p>This study merely shows a feasibility of using ISA and WG as replacement of clay in the brick manufacturing industry. More application can be tested in, for instance, concrete making, road pavement, etc. The presented results show that replacing different amounts of clay with WG and ISA affect the quality of bricks. In addition, pre-processing the raw materials dramatically increases the outcome quality. Important conclusions of this research are listed below.</p> <ol class="list" style="list-style-type:decimal"> <li><p>Grinding and sieving (<0.15 mm) the materials reduce the particle sizes and homogenize the materials, which increases the reacting area. This enhances the quality of the bricks. Compared to the pure clay standard, adding 30% of ground and sieved ISA increases the compressive strength by 31.6% and decreases the water absorption ratio by 11.8%</p></li> <li><p>Adding WG increases the overall quality of the brick and the substitution potential. Adding 40~50% of WG meets the third-class brick standard.</p></li> <li><p>Replacing 50% of clay with ISA while the other 50% of clay is replaced with glass is the best solution, with excellent waste utilization and the best compressive strength and water absorption ratio. However, considering the actual manufacturing process and the strength requirement, an ISA50%/WG40%/Clay10% ratio is recommended.</p></li> </ol></section><section id="notes1"><h2 class="pmc_sec_title">Author Contributions</h2> <p>Conceptualization, Y.-M.H. and C.-S.C.; methodology, C.-C.C.; software, J.-W.L.; validation, Y.-M.H., C.-S.C. and J.-W.L.; formal analysis, C.-C.C.; investigation, Y.-M.H.; resources, Y.-M.H. and C.-S.C.; data curation, J.-W.L.; writing—original draft preparation, Y.-M.H.; writing—review and editing, Y.-M.H. and J.-W.L.; visualization, C.-S.C.; supervision, C.-S.C.; project administration, Y.-M.H. and C.-S.C.; funding acquisition, Y.-M.H. and C.-S.C. All authors have read and agreed to the published version of the manuscript.</p></section><section id="notes2"><h2 class="pmc_sec_title">Institutional Review Board Statement</h2> <p>Not applicable.</p></section><section id="notes3"><h2 class="pmc_sec_title">Informed Consent Statement</h2> <p>Not applicable.</p></section><section id="notes4"><h2 class="pmc_sec_title">Data Availability Statement</h2> <p>Data are contained within the article.</p></section><section id="notes5"><h2 class="pmc_sec_title">Conflicts of Interest</h2> <p>The authors declare no conflict of interest.</p></section><section id="funding-statement1" lang="en"><h2 class="pmc_sec_title">Funding Statement</h2> <p>This research was funded by National Cheng Kung University.</p></section><section id="fn-group1" class="fn-group"><h2 class="pmc_sec_title">Footnotes</h2> <div class="fn-group p font-secondary-light font-sm"><div class="fn p" id="fn1"><p><strong>Disclaimer/Publisher’s Note:</strong> The statements, opinions and data contained in all publications are solely those of the individual author(s) and contributor(s) and not of MDPI and/or the editor(s). MDPI and/or the editor(s) disclaim responsibility for any injury to people or property resulting from any ideas, methods, instructions or products referred to in the content.</p></div></div></section><section id="ref-list1" class="ref-list"><h2 class="pmc_sec_title">References</h2> <section id="ref-list1_sec2"><ul class="ref-list font-sm" style="list-style-type:none"> <li id="B1-materials-17-02568"> <span class="label">1.</span><cite>Williford C., Chen W.Y., Shamas N.K., Wang L.K., Lime Stabilization . Biosolids Treatment Processes. Volume 6 Humana Press; Totowa, NI, USA: 2007. Handbook of Environmental Engineering.</cite> [<a href="https://scholar.google.com/scholar_lookup?title=Biosolids%20Treatment%20Processes&author=C.%20Williford&author=W.Y.%20Chen&author=N.K.%20Shamas&author=L.K.%20Wang&publication_year=2007&" class="usa-link usa-link--external" data-ga-action="click_feat_suppl" target="_blank" rel="noopener noreferrer">Google Scholar</a>]</li> <li id="B2-materials-17-02568"> <span class="label">2.</span><cite>Dennis A., Emmanuel O. The Impact of Taxation on Revenue Generation in Nigeria: A Study of Federal Capital Territory and Selected States. Int. J. Public Adm. Manag. Res. (IJPAMR) 2014;2:22–47.</cite> [<a href="https://scholar.google.com/scholar_lookup?journal=Int.%20J.%20Public%20Adm.%20Manag.%20Res.%20(IJPAMR)&title=The%20Impact%20of%20Taxation%20on%20Revenue%20Generation%20in%20Nigeria:%20A%20Study%20of%20Federal%20Capital%20Territory%20and%20Selected%20States&author=A.%20Dennis&author=O.%20Emmanuel&volume=2&publication_year=2014&pages=22-47&" class="usa-link usa-link--external" data-ga-action="click_feat_suppl" target="_blank" rel="noopener noreferrer">Google Scholar</a>]</li> <li id="B3-materials-17-02568"> <span class="label">3.</span><cite>Riaz M.H., Khitab A., Ahmed S. Evaluation of sustainable clay bricks incorporating Brick Kiln Dust. J. Eng. 2019;24:100725. doi: 10.1016/j.jobe.2019.02.017.</cite> [<a href="https://doi.org/10.1016/j.jobe.2019.02.017" class="usa-link usa-link--external" data-ga-action="click_feat_suppl" target="_blank" rel="noopener noreferrer">DOI</a>] [<a href="https://scholar.google.com/scholar_lookup?journal=J.%20Eng.&title=Evaluation%20of%20sustainable%20clay%20bricks%20incorporating%20Brick%20Kiln%20Dust&author=M.H.%20Riaz&author=A.%20Khitab&author=S.%20Ahmed&volume=24&publication_year=2019&pages=100725&doi=10.1016/j.jobe.2019.02.017&" class="usa-link usa-link--external" data-ga-action="click_feat_suppl" target="_blank" rel="noopener noreferrer">Google Scholar</a>]</li> <li id="B4-materials-17-02568"> <span class="label">4.</span><cite>Joung Y.J., Tseng Y.C., Cha S.C., Lo N.W., Chung G., Liu C.K. Motivations, Deployment, and Assessment of Taiwan’s E-Invoicing System: An Overview; Proceedings of the 47th Hawaii International Conference on System Sciences; Waikoloa, HI, USA. 6–9 January 2014; pp. 2200–2209.</cite> [<a href="https://scholar.google.com/scholar_lookup?journal=Proceedings%20of%20the%2047th%20Hawaii%20International%20Conference%20on%20System%20Sciences&title=Motivations,%20Deployment,%20and%20Assessment%20of%20Taiwan%E2%80%99s%20E-Invoicing%20System:%20An%20Overview&author=Y.J.%20Joung&author=Y.C.%20Tseng&author=S.C.%20Cha&author=N.W.%20Lo&author=G.%20Chung&pages=2200-2209&" class="usa-link usa-link--external" data-ga-action="click_feat_suppl" target="_blank" rel="noopener noreferrer">Google Scholar</a>]</li> <li id="B5-materials-17-02568"> <span class="label">5.</span><cite>Basegio T., Berutti F., Bernardes A., Bergmann C.P. Environmental and technical aspects of the utilisation of tannery sludge as a raw material for clay products. J. Eur. Ceram. Soc. 2002;22:2251–2259. doi: 10.1016/S0955-2219(02)00024-9.</cite> [<a href="https://doi.org/10.1016/S0955-2219(02)00024-9" class="usa-link usa-link--external" data-ga-action="click_feat_suppl" target="_blank" rel="noopener noreferrer">DOI</a>] [<a href="https://scholar.google.com/scholar_lookup?journal=J.%20Eur.%20Ceram.%20Soc.&title=Environmental%20and%20technical%20aspects%20of%20the%20utilisation%20of%20tannery%20sludge%20as%20a%20raw%20material%20for%20clay%20products&author=T.%20Basegio&author=F.%20Berutti&author=A.%20Bernardes&author=C.P.%20Bergmann&volume=22&publication_year=2002&pages=2251-2259&doi=10.1016/S0955-2219(02)00024-9&" class="usa-link usa-link--external" data-ga-action="click_feat_suppl" target="_blank" rel="noopener noreferrer">Google Scholar</a>]</li> <li id="B6-materials-17-02568"> <span class="label">6.</span><cite>Teixeira S.R., Santos G.T.A., Souza A.E., Alessio P., Souza S.A., Souza N.R. The effect of incorporation of a Brazilian water treatment plant sludge on the properties of ceramic materials. Appl. Clay Sci. 2011;53:561–565. doi: 10.1016/j.clay.2011.05.004.</cite> [<a href="https://doi.org/10.1016/j.clay.2011.05.004" class="usa-link usa-link--external" data-ga-action="click_feat_suppl" target="_blank" rel="noopener noreferrer">DOI</a>] [<a href="https://scholar.google.com/scholar_lookup?journal=Appl.%20Clay%20Sci.&title=The%20effect%20of%20incorporation%20of%20a%20Brazilian%20water%20treatment%20plant%20sludge%20on%20the%20properties%20of%20ceramic%20materials&author=S.R.%20Teixeira&author=G.T.A.%20Santos&author=A.E.%20Souza&author=P.%20Alessio&author=S.A.%20Souza&volume=53&publication_year=2011&pages=561-565&doi=10.1016/j.clay.2011.05.004&" class="usa-link usa-link--external" data-ga-action="click_feat_suppl" target="_blank" rel="noopener noreferrer">Google Scholar</a>]</li> <li id="B7-materials-17-02568"> <span class="label">7.</span><cite>Cheeseman C.R., Sollars C.J., McEntee S. Properties, microstructure and leaching of sintered sewage sludge ash. Resour. Conserv. Recycl. 2003;40:13–25. doi: 10.1016/S0921-3449(03)00022-3.</cite> [<a href="https://doi.org/10.1016/S0921-3449(03)00022-3" class="usa-link usa-link--external" data-ga-action="click_feat_suppl" target="_blank" rel="noopener noreferrer">DOI</a>] [<a href="https://scholar.google.com/scholar_lookup?journal=Resour.%20Conserv.%20Recycl.&title=Properties,%20microstructure%20and%20leaching%20of%20sintered%20sewage%20sludge%20ash&author=C.R.%20Cheeseman&author=C.J.%20Sollars&author=S.%20McEntee&volume=40&publication_year=2003&pages=13-25&doi=10.1016/S0921-3449(03)00022-3&" class="usa-link usa-link--external" data-ga-action="click_feat_suppl" target="_blank" rel="noopener noreferrer">Google Scholar</a>]</li> <li id="B8-materials-17-02568"> <span class="label">8.</span><cite>Chiang K.Y., Chien K.L., Hwang S.J. Study on the characteristics of building bricks produced from reservoir sediment. J. Hazard. Mater. 2008;159:499–504. doi: 10.1016/j.jhazmat.2008.02.046.</cite> [<a href="https://doi.org/10.1016/j.jhazmat.2008.02.046" class="usa-link usa-link--external" data-ga-action="click_feat_suppl" target="_blank" rel="noopener noreferrer">DOI</a>] [<a href="https://pubmed.ncbi.nlm.nih.gov/18384952/" class="usa-link">PubMed</a>] [<a href="https://scholar.google.com/scholar_lookup?journal=J.%20Hazard.%20Mater.&title=Study%20on%20the%20characteristics%20of%20building%20bricks%20produced%20from%20reservoir%20sediment&author=K.Y.%20Chiang&author=K.L.%20Chien&author=S.J.%20Hwang&volume=159&publication_year=2008&pages=499-504&pmid=18384952&doi=10.1016/j.jhazmat.2008.02.046&" class="usa-link usa-link--external" data-ga-action="click_feat_suppl" target="_blank" rel="noopener noreferrer">Google Scholar</a>]</li> <li id="B9-materials-17-02568"> <span class="label">9.</span><cite>Lin J.P., Shie J.L., Chang C.Y., Shih S.M., Lee D.J., Wu C.H. Pyrolysis of oil sludge with additives of catalytic solid wastes. J. Anal. Appl. Pyrolysis. 2004;71:695–707.</cite> [<a href="https://scholar.google.com/scholar_lookup?journal=J.%20Anal.%20Appl.%20Pyrolysis&title=Pyrolysis%20of%20oil%20sludge%20with%20additives%20of%20catalytic%20solid%20wastes&author=J.P.%20Lin&author=J.L.%20Shie&author=C.Y.%20Chang&author=S.M.%20Shih&author=D.J.%20Lee&volume=71&publication_year=2004&pages=695-707&" class="usa-link usa-link--external" data-ga-action="click_feat_suppl" target="_blank" rel="noopener noreferrer">Google Scholar</a>]</li> <li id="B10-materials-17-02568"> <span class="label">10.</span><cite>Taha Y., Benzaazoua M., Mansori M., Hakkou R. Recycling Feasibility of Glass Wastes and Calamine Processing Tailings in Fired Bricks Making. Waste Biomass Valorization. 2017;8:1479–1489. doi: 10.1007/s12649-016-9657-3.</cite> [<a href="https://doi.org/10.1007/s12649-016-9657-3" class="usa-link usa-link--external" data-ga-action="click_feat_suppl" target="_blank" rel="noopener noreferrer">DOI</a>] [<a href="https://scholar.google.com/scholar_lookup?journal=Waste%20Biomass%20Valorization&title=Recycling%20Feasibility%20of%20Glass%20Wastes%20and%20Calamine%20Processing%20Tailings%20in%20Fired%20Bricks%20Making&author=Y.%20Taha&author=M.%20Benzaazoua&author=M.%20Mansori&author=R.%20Hakkou&volume=8&publication_year=2017&pages=1479-1489&doi=10.1007/s12649-016-9657-3&" class="usa-link usa-link--external" data-ga-action="click_feat_suppl" target="_blank" rel="noopener noreferrer">Google Scholar</a>]</li> <li id="B11-materials-17-02568"> <span class="label">11.</span><cite>Mao L., Zhang M., Chen C., Wu Q. Use of electroplating sludge in production of fired clay bricks: Characterization and environmental risk evaluation. Constr. Build. Mater. 2018;159:27–36.</cite> [<a href="https://scholar.google.com/scholar_lookup?journal=Constr.%20Build.%20Mater.&title=Use%20of%20electroplating%20sludge%20in%20production%20of%20fired%20clay%20bricks:%20Characterization%20and%20environmental%20risk%20evaluation&author=L.%20Mao&author=M.%20Zhang&author=C.%20Chen&author=Q.%20Wu&volume=159&publication_year=2018&pages=27-36&" class="usa-link usa-link--external" data-ga-action="click_feat_suppl" target="_blank" rel="noopener noreferrer">Google Scholar</a>]</li> <li id="B12-materials-17-02568"> <span class="label">12.</span><cite>Munir M.J., Kazmi S.M.S., Gencel O., Ahmad M.R., Chen B. Synergistic effect of rice husk, glass and marble sludges on the engineering characteristics of eco-friendly bricks. J. Build. Eng. 2021;42:102484. doi: 10.1016/j.jobe.2021.102484.</cite> [<a href="https://doi.org/10.1016/j.jobe.2021.102484" class="usa-link usa-link--external" data-ga-action="click_feat_suppl" target="_blank" rel="noopener noreferrer">DOI</a>] [<a href="https://scholar.google.com/scholar_lookup?journal=J.%20Build.%20Eng.&title=Synergistic%20effect%20of%20rice%20husk,%20glass%20and%20marble%20sludges%20on%20the%20engineering%20characteristics%20of%20eco-friendly%20bricks&author=M.J.%20Munir&author=S.M.S.%20Kazmi&author=O.%20Gencel&author=M.R.%20Ahmad&author=B.%20Chen&volume=42&publication_year=2021&pages=102484&doi=10.1016/j.jobe.2021.102484&" class="usa-link usa-link--external" data-ga-action="click_feat_suppl" target="_blank" rel="noopener noreferrer">Google Scholar</a>]</li> <li id="B13-materials-17-02568"> <span class="label">13.</span><cite>Mao L., Wu Y., Zhang W., Huang Q. The reuse of waste glass for enhancement of heavy metals immobilization during the introduction of galvanized sludge in brick manufacturing. J. Environ. Manag. 2019;231:780–787. doi: 10.1016/j.jenvman.2018.10.120.</cite> [<a href="https://doi.org/10.1016/j.jenvman.2018.10.120" class="usa-link usa-link--external" data-ga-action="click_feat_suppl" target="_blank" rel="noopener noreferrer">DOI</a>] [<a href="https://pubmed.ncbi.nlm.nih.gov/30415171/" class="usa-link">PubMed</a>] [<a href="https://scholar.google.com/scholar_lookup?journal=J.%20Environ.%20Manag.&title=The%20reuse%20of%20waste%20glass%20for%20enhancement%20of%20heavy%20metals%20immobilization%20during%20the%20introduction%20of%20galvanized%20sludge%20in%20brick%20manufacturing&author=L.%20Mao&author=Y.%20Wu&author=W.%20Zhang&author=Q.%20Huang&volume=231&publication_year=2019&pages=780-787&pmid=30415171&doi=10.1016/j.jenvman.2018.10.120&" class="usa-link usa-link--external" data-ga-action="click_feat_suppl" target="_blank" rel="noopener noreferrer">Google Scholar</a>]</li> <li id="B14-materials-17-02568"> <span class="label">14.</span><cite>Loryuenyong V., Panyachai T., Kaewsimork K., Siritai C. Effects of recycled glass substitution on the physical and mechanical properties of clay bricks. Waste Manag. 2009;29:2717–2721. doi: 10.1016/j.wasman.2009.05.015.</cite> [<a href="https://doi.org/10.1016/j.wasman.2009.05.015" class="usa-link usa-link--external" data-ga-action="click_feat_suppl" target="_blank" rel="noopener noreferrer">DOI</a>] [<a href="https://pubmed.ncbi.nlm.nih.gov/19545990/" class="usa-link">PubMed</a>] [<a href="https://scholar.google.com/scholar_lookup?journal=Waste%20Manag.&title=Effects%20of%20recycled%20glass%20substitution%20on%20the%20physical%20and%20mechanical%20properties%20of%20clay%20bricks&author=V.%20Loryuenyong&author=T.%20Panyachai&author=K.%20Kaewsimork&author=C.%20Siritai&volume=29&publication_year=2009&pages=2717-2721&pmid=19545990&doi=10.1016/j.wasman.2009.05.015&" class="usa-link usa-link--external" data-ga-action="click_feat_suppl" target="_blank" rel="noopener noreferrer">Google Scholar</a>]</li> <li id="B15-materials-17-02568"> <span class="label">15.</span><cite>Phonphuak N., Kanyakam S., Chindaprasirt P. Utilization of waste glass to enhance physical–mechanical properties of fired clay brick. Pt 4J. Clean. Prod. 2016;112:3057–3062. doi: 10.1016/j.jclepro.2015.10.084.</cite> [<a href="https://doi.org/10.1016/j.jclepro.2015.10.084" class="usa-link usa-link--external" data-ga-action="click_feat_suppl" target="_blank" rel="noopener noreferrer">DOI</a>] [<a href="https://scholar.google.com/scholar_lookup?journal=J.%20Clean.%20Prod.&title=Utilization%20of%20waste%20glass%20to%20enhance%20physical%E2%80%93mechanical%20properties%20of%20fired%20clay%20brick&author=N.%20Phonphuak&author=S.%20Kanyakam&author=P.%20Chindaprasirt&volume=112&publication_year=2016&pages=3057-3062&doi=10.1016/j.jclepro.2015.10.084&" class="usa-link usa-link--external" data-ga-action="click_feat_suppl" target="_blank" rel="noopener noreferrer">Google Scholar</a>]</li> <li id="B16-materials-17-02568"> <span class="label">16.</span><cite>Ministry of Finance, R.O.C 2021. [(accessed on 21 May 2021)]; Available online: <a href="https://web02.mof.gov.tw/njswww/WebMain.aspx?sys=100&funid=defjsptgl" class="usa-link usa-link--external" data-ga-action="click_feat_suppl" target="_blank" rel="noopener noreferrer">https://web02.mof.gov.tw/njswww/WebMain.aspx?sys=100&funid=defjsptgl</a>.</cite> </li> <li id="B17-materials-17-02568"> <span class="label">17.</span><cite>Bureau of Standards, Metrology and Inspection, M.O.E.A., R.O.C [(accessed on 21 May 2021)]. Available online: <a href="https://www.cnsonline.com.tw/?locale=zh_TW" class="usa-link usa-link--external" data-ga-action="click_feat_suppl" target="_blank" rel="noopener noreferrer">https://www.cnsonline.com.tw/?locale=zh_TW</a>.</cite> </li> <li id="B18-materials-17-02568"> <span class="label">18.</span><cite>ASTM International. USA [(accessed on 21 May 2021)]. Available online: <a href="https://www.astm.org/" class="usa-link usa-link--external" data-ga-action="click_feat_suppl" target="_blank" rel="noopener noreferrer">https://www.astm.org/</a></cite> </li> <li id="B19-materials-17-02568"> <span class="label">19.</span><cite>Standard Test Methods for Sampling and Testing Brick and Structural Clay Tile. ASTM International; West Conshohocken, PA, USA: 2014. </cite> [<a href="https://scholar.google.com/scholar_lookup?title=Standard%20Test%20Methods%20for%20Sampling%20and%20Testing%20Brick%20and%20Structural%20Clay%20Tile&publication_year=2014&" class="usa-link usa-link--external" data-ga-action="click_feat_suppl" target="_blank" rel="noopener noreferrer">Google Scholar</a>]</li> <li id="B20-materials-17-02568"> <span class="label">20.</span><cite>Skrifvars B.J., Hupa M., Backman R., Hiltunen M. Sintering mechanisms of FBC ashes. Fuel. 1994;73:171–176. doi: 10.1016/0016-2361(94)90110-4.</cite> [<a href="https://doi.org/10.1016/0016-2361(94)90110-4" class="usa-link usa-link--external" data-ga-action="click_feat_suppl" target="_blank" rel="noopener noreferrer">DOI</a>] [<a href="https://scholar.google.com/scholar_lookup?journal=Fuel&title=Sintering%20mechanisms%20of%20FBC%20ashes&author=B.J.%20Skrifvars&author=M.%20Hupa&author=R.%20Backman&author=M.%20Hiltunen&volume=73&publication_year=1994&pages=171-176&doi=10.1016/0016-2361(94)90110-4&" class="usa-link usa-link--external" data-ga-action="click_feat_suppl" target="_blank" rel="noopener noreferrer">Google Scholar</a>]</li> <li id="B21-materials-17-02568"> <span class="label">21.</span><cite>Yeh K.Y., Yeh M., Glass J. Hepcidin regulation of ferroportin 1 expression in the liver and intestine of the rat. Am. J. Physiol. 2004;286:G385–G394. doi: 10.1152/ajpgi.00246.2003.</cite> [<a href="https://doi.org/10.1152/ajpgi.00246.2003" class="usa-link usa-link--external" data-ga-action="click_feat_suppl" target="_blank" rel="noopener noreferrer">DOI</a>] [<a href="https://pubmed.ncbi.nlm.nih.gov/14592944/" class="usa-link">PubMed</a>] [<a href="https://scholar.google.com/scholar_lookup?journal=Am.%20J.%20Physiol.&title=Hepcidin%20regulation%20of%20ferroportin%201%20expression%20in%20the%20liver%20and%20intestine%20of%20the%20rat&author=K.Y.%20Yeh&author=M.%20Yeh&author=J.%20Glass&volume=286&publication_year=2004&pages=G385-G394&pmid=14592944&doi=10.1152/ajpgi.00246.2003&" class="usa-link usa-link--external" data-ga-action="click_feat_suppl" target="_blank" rel="noopener noreferrer">Google Scholar</a>]</li> <li id="B22-materials-17-02568"> <span class="label">22.</span><cite>Chen Z., Zhou C., Du B., Wang N. Preparation and strength property of autoclaved bricks from electrolytic manganese residue. J. Clean. Prod. 2014;84:707–714.</cite> [<a href="https://scholar.google.com/scholar_lookup?journal=J.%20Clean.%20Prod.&title=Preparation%20and%20strength%20property%20of%20autoclaved%20bricks%20from%20electrolytic%20manganese%20residue&author=Z.%20Chen&author=C.%20Zhou&author=B.%20Du&author=N.%20Wang&volume=84&publication_year=2014&pages=707-714&" class="usa-link usa-link--external" data-ga-action="click_feat_suppl" target="_blank" rel="noopener noreferrer">Google Scholar</a>]</li> <li id="B23-materials-17-02568"> <span class="label">23.</span><cite>Park W.W., Choi B.H., You B.S., Huang Y.B., Park I.M. Effect of Ca addition on the oxidation resistance of AZ91 magnesium alloys at elevated temperatures. Met. Mater. Int. 2003;9:395–398.</cite> [<a href="https://scholar.google.com/scholar_lookup?journal=Met.%20Mater.%20Int.&title=Effect%20of%20Ca%20addition%20on%20the%20oxidation%20resistance%20of%20AZ91%20magnesium%20alloys%20at%20elevated%20temperatures&author=W.W.%20Park&author=B.H.%20Choi&author=B.S.%20You&author=Y.B.%20Huang&author=I.M.%20Park&volume=9&publication_year=2003&pages=395-398&" class="usa-link usa-link--external" data-ga-action="click_feat_suppl" target="_blank" rel="noopener noreferrer">Google Scholar</a>]</li> <li id="B24-materials-17-02568"> <span class="label">24.</span><cite>Reich J. Slag from hazardous waste incineration: Reduction of heavy metal leaching. Waste Manag. Res. 2003;21:110–118. doi: 10.1177/0734242X0302100204.</cite> [<a href="https://doi.org/10.1177/0734242X0302100204" class="usa-link usa-link--external" data-ga-action="click_feat_suppl" target="_blank" rel="noopener noreferrer">DOI</a>] [<a href="https://pubmed.ncbi.nlm.nih.gov/12739725/" class="usa-link">PubMed</a>] [<a href="https://scholar.google.com/scholar_lookup?journal=Waste%20Manag.%20Res.&title=Slag%20from%20hazardous%20waste%20incineration:%20Reduction%20of%20heavy%20metal%20leaching&author=J.%20Reich&volume=21&publication_year=2003&pages=110-118&pmid=12739725&doi=10.1177/0734242X0302100204&" class="usa-link usa-link--external" data-ga-action="click_feat_suppl" target="_blank" rel="noopener noreferrer">Google Scholar</a>]</li> </ul></section></section><section id="_ad93_" lang="en" class="associated-data"><h2 class="pmc_sec_title">Associated Data</h2> <p class="font-secondary"><em>This section collects any data citations, data availability statements, or supplementary materials included in this article.</em></p> <section id="_adda93_" lang="en" class="data-availability-statement"><h3 class="pmc_sec_title">Data Availability Statement</h3> <p>Data are contained within the article.</p></section></section></section><footer class="p courtesy-note font-secondary font-sm text-center"><hr class="headless"> <p>Articles from Materials are provided here courtesy of <strong>Multidisciplinary Digital Publishing Institute (MDPI)</strong></p></footer></section></article> </main> </div> </div> </div> <!-- Secondary navigation placeholder --> <div class="pmc-sidenav desktop:grid-col-4 display-flex"> <section class="pmc-sidenav__container" aria-label="Article resources and navigation"> <button type="button" class="usa-button pmc-sidenav__container__close usa-button--unstyled"> <img src="/static/img/usa-icons/close.svg" role="img" alt="Close" /> </button> <div class="display-none desktop:display-block"> <section class="margin-top-4 desktop:margin-top-0"> <h2 class="margin-top-0">ACTIONS</h2> <ul class="usa-list usa-list--unstyled usa-list--actions"> <li> <a href="https://doi.org/10.3390/ma17112568" class="usa-button usa-button--outline width-24 font-xs usa-link--external padding-left-0 padding-right-0" target="_blank" rel="noreferrer noopener" data-ga-category="actions" data-ga-action="click" data-ga-label="publisher_link_desktop" > <span class="height-3 display-inline-flex flex-align-center">View on publisher site</span> </a> </li> <li> <a href="pdf/materials-17-02568.pdf" class="usa-button usa-button--outline width-24 display-inline-flex flex-align-center flex-justify-start padding-left-1" data-ga-category="actions" data-ga-action="click" data-ga-label="pdf_download_desktop" > <svg class="usa-icon width-3 height-3" aria-hidden="true" focusable="false" role="img" hidden> <use xlink:href="/static/img/sprite.svg#file_download"></use> </svg> <span class="display-inline-flex flex-justify-center flex-1">PDF (4.3 MB)</span> </a> </li> <li> <button role="button" class="usa-button width-24 citation-dialog-trigger display-inline-flex flex-align-center flex-justify-start padding-left-1" aria-label="Open dialog with citation text in different styles" data-ga-category="actions" data-ga-action="open" data-ga-label="cite_desktop" data-all-citations-url="/resources/citations/11173697/" data-citation-style="nlm" data-download-format-link="/resources/citations/11173697/export/" > <svg class="usa-icon width-3 height-3" aria-hidden="true" focusable="false" role="img" hidden> <use xlink:href="/static/img/sprite.svg#format_quote"></use> </svg> <span class="display-inline-flex flex-justify-center flex-1 button-label">Cite</span> </button> </li> <li> <button class="usa-button width-24 collections-dialog-trigger collections-button display-inline-flex flex-align-center flex-justify-start padding-left-1 collections-button-empty" aria-label="Save article in MyNCBI collections." data-ga-category="actions" data-ga-action="click" data-ga-label="collections_button_desktop" data-collections-open-dialog-enabled="false" data-collections-open-dialog-url="https://account.ncbi.nlm.nih.gov/?back_url=https%3A%2F%2Fpmc.ncbi.nlm.nih.gov%2Farticles%2FPMC11173697%2F%23open-collections-dialog" data-in-collections="false"> <svg class="usa-icon width-3 height-3 usa-icon--bookmark-full" aria-hidden="true" focusable="false" role="img" hidden> <use xlink:href="/static/img/action-bookmark-full.svg#icon"></use> </svg> <svg class="usa-icon width-3 height-3 usa-icon--bookmark-empty" aria-hidden="true" focusable="false" role="img" hidden> <use xlink:href="/static/img/action-bookmark-empty.svg#icon"></use> </svg> <span class="display-inline-flex flex-justify-center flex-1">Collections</span> </button> </li> <li class="pmc-permalink"> <button type="button" class="usa-button usa-button--outline width-24 display-inline-flex flex-align-center flex-justify padding-left-1 shadow-none" aria-label="Show article permalink" aria-expanded="false" aria-haspopup="true" data-ga-category="actions" data-ga-action="open" data-ga-label="permalink_desktop" > <svg class="usa-icon width-3 height-3" aria-hidden="true" focusable="false" role="img" hidden> <use xlink:href="/static/img/sprite.svg#share"></use> </svg> <span class="display-inline-flex flex-justify-center flex-1 button-label">Permalink</span> </button> <div class="pmc-permalink__dropdown" hidden> <div class="pmc-permalink__dropdown__container"> <h2 class="usa-modal__heading margin-top-0 margin-bottom-2">PERMALINK</h2> <div class="pmc-permalink__dropdown__content"> <input type="text" class="usa-input" value="https://pmc.ncbi.nlm.nih.gov/articles/PMC11173697/" aria-label="Article permalink"> <button class="usa-button display-inline-flex pmc-permalink__dropdown__copy__btn margin-right-0" title="Copy article permalink" data-ga-category="save_share" data-ga-action="link" data-ga-label="copy_link"> <svg class="usa-icon" aria-hidden="true" focusable="false" role="img"> <use xlink:href="/static/img/sprite.svg#content_copy"></use> </svg> <span class="margin-left-1">Copy</span> </button> </div> </div> </div> </li> </ul> </section> </div> <section class="pmc-resources margin-top-6 desktop:margin-top-4" data-page-path="/articles/PMC11173697/"> <h2 class="margin-top-0">RESOURCES</h2> <div class="usa-accordion usa-accordion--multiselectable" data-allow-multiple> <h3 class="usa-accordion__heading"> <button type="button" class="usa-accordion__button" aria-expanded="false" aria-controls="resources-similar-articles" data-ga-category="resources_accordion" data-ga-action="open_similar_articles" data-ga-label="/articles/PMC11173697/" data-action-open="open_similar_articles" data-action-close="close_similar_articles" > Similar articles </button> </h3> <div id="resources-similar-articles" class="usa-accordion__content usa-prose" data-source-url="/resources/similar-article-links/38893832/" > </div> <h3 class="usa-accordion__heading"> <button type="button" class="usa-accordion__button" aria-expanded="false" aria-controls="resources-cited-by-other-articles" data-ga-category="resources_accordion" data-ga-action="open_cited_by" data-ga-label="/articles/PMC11173697/" data-action-open="open_cited_by" data-action-close="close_cited_by" > Cited by other articles </button> </h3> <div id="resources-cited-by-other-articles" class="usa-accordion__content usa-prose" data-source-url="/resources/cited-by-links/38893832/" > </div> <h3 class="usa-accordion__heading"> <button type="button" class="usa-accordion__button" aria-expanded="false" aria-controls="resources-links-to-ncbi-databases" data-ga-category="resources_accordion" data-ga-action="open_NCBI_links" data-ga-label="/articles/PMC11173697/" data-action-open="open_NCBI_links" data-action-close="close_NCBI_link" > Links to NCBI Databases </button> </h3> <div id="resources-links-to-ncbi-databases" class="usa-accordion__content usa-prose" data-source-url="/resources/db-links/11173697/" > </div> </div> </section> <section class="usa-in-page-nav usa-in-page-nav--wide margin-top-6 desktop:margin-top-4" data-title-text="On this page" data-title-heading-level="h2" data-scroll-offset="0" data-root-margin="-10% 0px -80% 0px" data-main-content-selector="main" data-threshold="1" hidden ></section> </section> </div> <div class="overlay" role="dialog" aria-label="Citation Dialog" hidden> <div class="dialog citation-dialog" aria-hidden="true"> <div class="display-inline-flex flex-align-center flex-justify width-full margin-bottom-2"> <h2 class="usa-modal__heading margin-0">Cite</h2> <button type="button" class="usa-button usa-button--unstyled close-overlay text-black width-auto" tabindex="1"> <svg class="usa-icon width-3 height-3" aria-hidden="true" focusable="false" role="img"> <use xlink:href="/static/img/sprite.svg#close"></use> </svg> </button> </div> <div class="citation-text-block"> <div class="citation-text margin-bottom-2"></div> <ul class="usa-list usa-list--unstyled display-inline-flex flex-justify width-full flex-align-center"> <li> <button class="usa-button usa-button--unstyled text-no-underline display-flex flex-align-center copy-button dialog-focus" data-ga-category="save_share" data-ga-action="cite" data-ga-label="copy" tabindex="2"> <svg class="usa-icon width-3 height-3" aria-hidden="true" focusable="false" role="img"> <use xlink:href="/static/img/sprite.svg#content_copy"></use> </svg> <span>Copy</span> </button> </li> <li> <a href="#" role="button" class="usa-button usa-button--unstyled text-no-underline display-flex flex-align-center export-button" data-ga-category="save_share" data-ga-action="cite" data-ga-label="download" title="Download a file for external citation management software" tabindex="3"> <svg class="usa-icon width-3 height-3" aria-hidden="true" focusable="false" role="img"> <use xlink:href="/static/img/sprite.svg#file_download"></use> </svg> <span class="display-none mobile-lg:display-inline">Download .nbib</span> <span class="display-inline mobile-lg:display-none">.nbib</span> </a> </li> <li> <div class="display-inline-flex flex-align-center"> <label class="usa-label margin-top-0">Format:</label> <select aria-label="Format" class="usa-select citation-style-selector padding-1 margin-top-0 border-0 padding-right-4" tabindex="4" > <option data-style-url-name="ama" value="AMA" > AMA </option> <option data-style-url-name="apa" value="APA" > APA </option> <option data-style-url-name="mla" value="MLA" > MLA </option> <option data-style-url-name="nlm" value="NLM" selected="selected"> NLM </option> </select> </div> </li> </ul> </div> </div> </div> <div class="overlay" role="dialog" hidden> <div id="collections-action-dialog" class="dialog collections-dialog" aria-hidden="true"> <div class="display-inline-flex flex-align-center flex-justify width-full margin-bottom-2"> <h2 class="usa-modal__heading margin-0">Add to Collections</h2> </div> <div class="collections-action-panel action-panel"> <form id="collections-action-dialog-form" class="usa-form maxw-full collections-action-panel-form action-panel-content action-form action-panel-smaller-selectors" data-existing-collections-url="/list-existing-collections/" data-add-to-existing-collection-url="/add-to-existing-collection/" data-create-and-add-to-new-collection-url="/create-and-add-to-new-collection/" data-myncbi-max-collection-name-length="100" data-collections-root-url="https://www.ncbi.nlm.nih.gov/myncbi/collections/"> <input type="hidden" name="csrfmiddlewaretoken" value="zXJLeDzOd2KWONYKYXkwcjXr4Nm1HC8KyhEEw2FqnCMKUKhH2gIfuqM73WSJt47y"> <fieldset class="usa-fieldset margin-bottom-2"> <div class="usa-radio"> <input type="radio" id="collections-action-dialog-new" class="usa-radio__input usa-radio__input--tile collections-new margin-top-0" name="collections" value="new" data-ga-category="collections_button" data-ga-action="click" data-ga-label="collections_radio_new" /> <label class="usa-radio__label" for="collections-action-dialog-new">Create a new collection</label> </div> <div class="usa-radio"> <input type="radio" id="collections-action-dialog-existing" class="usa-radio__input usa-radio__input--tile collections-existing" name="collections" value="existing" checked="true" data-ga-category="collections_button" data-ga-action="click" data-ga-label="collections_radio_existing" /> <label class="usa-radio__label" for="collections-action-dialog-existing">Add to an existing collection</label> </div> </fieldset> <fieldset class="usa-fieldset margin-bottom-2"> <div class="action-panel-control-wrap new-collections-controls"> <label for="collections-action-dialog-add-to-new" class="usa-label margin-top-0"> Name your collection <abbr title="required" class="usa-hint usa-hint--required text-no-underline">*</abbr> </label> <input type="text" name="add-to-new-collection" id="collections-action-dialog-add-to-new" class="usa-input collections-action-add-to-new" pattern="[^"&=<>/]*" title="The following characters are not allowed in the Name field: "&=<>/" maxlength="" data-ga-category="collections_button" data-ga-action="create_collection" data-ga-label="non_favorties_collection" required /> </div> <div class="action-panel-control-wrap existing-collections-controls"> <label for="collections-action-dialog-add-to-existing" class="usa-label margin-top-0"> Choose a collection </label> <select id="collections-action-dialog-add-to-existing" class="usa-select collections-action-add-to-existing" data-ga-category="collections_button" data-ga-action="select_collection" data-ga-label="($('.collections-action-add-to-existing').val() === 'Favorites') ? 'Favorites' : 'non_favorites_collection'"> </select> <div class="collections-retry-load-on-error usa-input-error-message selection-validation-message"> Unable to load your collection due to an error<br> <a href="#">Please try again</a> </div> </div> </fieldset> <div class="display-inline-flex"> <button class="usa-button margin-top-0 action-panel-submit" type="submit" data-loading-label="Adding..." data-pinger-ignore data-ga-category="collections_button" data-ga-action="click" data-ga-label="add"> Add </button> <button class="usa-button usa-button--outline margin-top-0 action-panel-cancel" aria-label="Close 'Add to Collections' panel" ref="linksrc=close_collections_panel" data-ga-category="collections_button" data-ga-action="click" data-ga-label="cancel"> Cancel </button> </div> </form> </div> </div> </div> </div> </div> </div> <footer class="ncbi-footer ncbi-dark-background " > <div class="ncbi-footer__icon-section"> <div class="ncbi-footer__social-header"> Follow NCBI </div> <div class="grid-container ncbi-footer__ncbi-social-icons-container"> <a href="https://twitter.com/ncbi" class="ncbi-footer__social-icon ncbi-footer__social-icon--gray" target="_blank" rel="noreferrer noopener"> <svg width="40" height="40" viewBox="0 0 40 40" fill="none" xmlns="http://www.w3.org/2000/svg" focusable="false" aria-hidden="true"> <path d="m6.067 8 10.81 13.9L6 33.2h4.2l8.4-9.1 7.068 9.1H34L22.8 18.5 31.9 8h-3.5l-7.7 8.4L14.401 8H6.067Zm3.6 1.734h3.266l16.8 21.732H26.57L9.668 9.734Z"> </path> </svg> <span class="usa-sr-only">NCBI on X (formerly known as Twitter)</span> </a> <a href="https://www.facebook.com/ncbi.nlm" class="ncbi-footer__social-icon ncbi-footer__social-icon--gray" target="_blank" rel="noreferrer noopener"> <svg width="16" height="29" focusable="false" aria-hidden="true" viewBox="0 0 16 29" fill="none" xmlns="http://www.w3.org/2000/svg"> <path d="M3.8809 21.4002C3.8809 19.0932 3.8809 16.7876 3.8809 14.478C3.8809 14.2117 3.80103 14.1452 3.54278 14.1492C2.53372 14.1638 1.52334 14.1492 0.514288 14.1598C0.302626 14.1598 0.248047 14.0972 0.248047 13.8936C0.256034 12.4585 0.256034 11.0239 0.248047 9.58978C0.248047 9.37013 0.302626 9.30224 0.528931 9.3049C1.53798 9.31688 2.54837 9.3049 3.55742 9.31555C3.80103 9.31555 3.8809 9.26097 3.87957 9.00272C3.87158 8.00565 3.85428 7.00592 3.90753 6.00884C3.97142 4.83339 4.31487 3.73115 5.04437 2.78467C5.93095 1.63318 7.15699 1.09005 8.56141 0.967577C10.5582 0.79319 12.555 0.982221 14.5518 0.927641C14.7102 0.927641 14.7462 0.99287 14.7449 1.13664C14.7449 2.581 14.7449 4.02668 14.7449 5.47104C14.7449 5.67604 14.6517 5.68669 14.4946 5.68669C13.4523 5.68669 12.4113 5.68669 11.3703 5.68669C10.3506 5.68669 9.92057 6.10868 9.90593 7.13904C9.89661 7.7647 9.91525 8.39303 9.89794 9.01869C9.88995 9.26364 9.96583 9.31822 10.2015 9.31688C11.7204 9.30623 13.2393 9.31688 14.7595 9.3049C15.0257 9.3049 15.0723 9.3728 15.0444 9.62439C14.89 10.9849 14.7515 12.3467 14.6144 13.7085C14.5691 14.1571 14.5785 14.1585 14.1458 14.1585C12.8386 14.1585 11.5313 14.1665 10.2254 14.1518C9.95119 14.1518 9.89794 14.2317 9.89794 14.4899C9.90593 19.0799 9.89794 23.6752 9.91125 28.2612C9.91125 28.5674 9.8407 28.646 9.53186 28.6433C7.77866 28.6273 6.02414 28.6366 4.27094 28.634C3.82499 28.634 3.87158 28.6992 3.87158 28.22C3.87602 25.9472 3.87913 23.6739 3.8809 21.4002Z"> </path> </svg> <span class="usa-sr-only">NCBI on Facebook</span> </a> <a href="https://www.linkedin.com/company/ncbinlm" class="ncbi-footer__social-icon ncbi-footer__social-icon--gray" target="_blank" rel="noreferrer noopener"> <svg width="25" height="23" viewBox="0 0 26 24" fill="none" xmlns="http://www.w3.org/2000/svg" focusable="false" aria-hidden="true"> <path d="M14.6983 9.98423C15.6302 9.24808 16.5926 8.74754 17.6762 8.51991C19.673 8.09126 21.554 8.30824 23.1262 9.7526C24.2351 10.7723 24.7529 12.1115 25.0165 13.5612C25.1486 14.3363 25.2105 15.1218 25.2015 15.9081C25.2015 18.3043 25.2015 20.6898 25.2082 23.0806C25.2082 23.3468 25.1549 23.444 24.8621 23.4414C23.1297 23.4272 21.3992 23.4272 19.6704 23.4414C19.4041 23.4414 19.3429 23.3588 19.3442 23.1019C19.3535 20.5194 19.3442 17.9368 19.3442 15.3543C19.3442 14.0005 18.3258 12.9448 17.0266 12.9488C15.7273 12.9528 14.6983 14.0071 14.6983 15.361C14.6983 17.9328 14.6917 20.5047 14.6983 23.0753C14.6983 23.3708 14.6198 23.444 14.3296 23.4427C12.6185 23.4294 10.9079 23.4294 9.19779 23.4427C8.93155 23.4427 8.86099 23.3735 8.86232 23.1086C8.8783 19.7619 8.88628 16.4144 8.88628 13.066C8.88628 11.5688 8.87874 10.0708 8.86365 8.57182C8.86365 8.3575 8.90758 8.27896 9.14054 8.28029C10.9048 8.29094 12.6687 8.29094 14.4321 8.28029C14.6464 8.28029 14.6983 8.34818 14.6983 8.54653C14.6903 9.00047 14.6983 9.45441 14.6983 9.98423Z"> </path> <path d="M6.55316 15.8443C6.55316 18.2564 6.55316 20.6699 6.55316 23.082C6.55316 23.3629 6.48127 23.4388 6.19906 23.4374C4.47737 23.4241 2.75568 23.4241 1.03399 23.4374C0.767751 23.4374 0.69986 23.3629 0.701191 23.1006C0.709178 18.2648 0.709178 13.4281 0.701191 8.59053C0.701191 8.34026 0.765089 8.27237 1.01669 8.2737C2.74991 8.28435 4.48048 8.28435 6.20838 8.2737C6.47462 8.2737 6.5465 8.33627 6.54517 8.6065C6.54783 11.0186 6.55316 13.4308 6.55316 15.8443Z"> </path> <path d="M3.65878 0.243898C5.36804 0.243898 6.58743 1.45529 6.58743 3.1406C6.58743 4.75801 5.32145 5.95742 3.60819 5.96807C3.22177 5.97614 2.83768 5.90639 2.47877 5.76299C2.11985 5.61959 1.79344 5.40546 1.51897 5.13334C1.24449 4.86123 1.02755 4.53668 0.881058 4.17902C0.734563 3.82136 0.661505 3.43788 0.666231 3.05141C0.67555 1.42601 1.9362 0.242566 3.65878 0.243898Z"> </path> </svg> <span class="usa-sr-only">NCBI on LinkedIn</span> </a> <a href="https://github.com/ncbi" class="ncbi-footer__social-icon ncbi-footer__social-icon--gray" target="_blank" rel="noreferrer noopener"> <svg width="28" height="27" viewBox="0 0 28 28" fill="none" xmlns="http://www.w3.org/2000/svg" focusable="false" aria-hidden="true"> <path d="M16.7228 20.6334C17.5057 20.5527 18.2786 20.3944 19.0301 20.1608C21.3108 19.4193 22.5822 17.8259 22.963 15.4909C23.1228 14.5112 23.1814 13.5287 22.9883 12.5437C22.8106 11.6423 22.4013 10.8028 21.8007 10.1076C21.7526 10.0605 21.7197 10 21.7064 9.934C21.6931 9.86799 21.7 9.79952 21.7262 9.73748C22.0856 8.6206 21.9711 7.51969 21.601 6.42677C21.582 6.3497 21.5345 6.2827 21.468 6.23923C21.4016 6.19577 21.3211 6.17906 21.2429 6.19248C20.7329 6.21649 20.2313 6.33051 19.7611 6.52928C19.1103 6.7908 18.4899 7.12198 17.9104 7.51703C17.84 7.56996 17.7581 7.60551 17.6713 7.62078C17.5846 7.63605 17.4954 7.6306 17.4112 7.60489C15.2596 7.05882 13.0054 7.06203 10.8554 7.61421C10.7806 7.63586 10.7018 7.63967 10.6253 7.62534C10.5487 7.611 10.4766 7.57892 10.4148 7.53167C9.64788 7.03247 8.85171 6.58918 7.96368 6.33359C7.65781 6.24338 7.34123 6.19458 7.02239 6.18849C6.94879 6.17986 6.87462 6.19893 6.81432 6.242C6.75402 6.28507 6.71191 6.34904 6.69621 6.42145C6.32342 7.51437 6.2209 8.61527 6.56307 9.73348C6.59635 9.84264 6.64694 9.93316 6.54177 10.0516C5.47666 11.2604 5.09988 12.6834 5.19574 14.2676C5.2663 15.4244 5.46201 16.5466 6.01454 17.5769C6.84399 19.1171 8.21664 19.9119 9.85158 20.3352C10.3938 20.4706 10.9444 20.5698 11.4998 20.632C11.5384 20.7492 11.4506 20.7798 11.408 20.8291C11.1734 21.1179 10.9894 21.4441 10.8634 21.7942C10.7622 22.0458 10.8315 22.4039 10.6065 22.5516C10.263 22.7766 9.83827 22.8485 9.42421 22.8871C8.17936 23.0056 7.26471 22.4877 6.6283 21.4348C6.25552 20.8184 5.76956 20.3325 5.08523 20.0663C4.76981 19.9325 4.42139 19.8967 4.08537 19.9638C3.7898 20.029 3.73788 20.1901 3.93891 20.4111C4.03639 20.5234 4.14989 20.6207 4.27575 20.6999C4.9796 21.1318 5.51717 21.7884 5.80152 22.5636C6.37002 23.9973 7.48039 24.5697 8.93825 24.6323C9.43741 24.6575 9.93768 24.615 10.4254 24.5058C10.5892 24.4672 10.6531 24.4872 10.6517 24.6762C10.6451 25.4936 10.6637 26.3123 10.6517 27.131C10.6517 27.6635 10.1684 27.9297 9.58663 27.7393C8.17396 27.2671 6.84977 26.5631 5.66838 25.656C2.59555 23.2891 0.720966 20.1861 0.217704 16.3376C-0.357453 11.9127 0.911353 8.00824 3.98551 4.73881C6.11909 2.42656 8.99932 0.939975 12.1203 0.540191C16.5351 -0.0601815 20.4347 1.14323 23.7232 4.16373C26.2449 6.47869 27.724 9.37672 28.1048 12.7726C28.5828 17.0325 27.3686 20.7945 24.4768 23.9827C22.9762 25.6323 21.0956 26.8908 18.9982 27.6488C18.8783 27.6927 18.7585 27.738 18.636 27.7726C18.0356 27.9404 17.6189 27.6395 17.6189 27.0098C17.6189 25.7452 17.6308 24.4806 17.6295 23.2159C17.6329 22.9506 17.6128 22.6856 17.5696 22.4238C17.4325 21.6664 17.3419 21.484 16.7228 20.6334Z"> </path> </svg> <span class="usa-sr-only">NCBI on GitHub</span> </a> <a href="https://ncbiinsights.ncbi.nlm.nih.gov/" class="ncbi-footer__social-icon ncbi-footer__social-icon--gray" target="_blank" rel="noreferrer noopener"> <svg width="26" height="26" viewBox="0 0 27 27" fill="none" xmlns="http://www.w3.org/2000/svg" focusable="false" aria-hidden="true"> <path d="M23.7778 26.4574C23.1354 26.3913 22.0856 26.8024 21.636 26.3087C21.212 25.8444 21.4359 24.8111 21.324 24.0347C19.9933 14.8323 14.8727 8.80132 6.09057 5.85008C4.37689 5.28406 2.58381 4.99533 0.779072 4.99481C0.202773 4.99481 -0.0229751 4.83146 0.00455514 4.21479C0.0660406 3.08627 0.0660406 1.95525 0.00455514 0.826734C-0.0413285 0.0815827 0.259669 -0.0193618 0.896534 0.00266238C6.96236 0.222904 12.3693 2.24179 16.9889 6.16209C22.9794 11.2478 26.1271 17.7688 26.4372 25.648C26.4629 26.294 26.3179 26.5271 25.6609 26.4684C25.0827 26.417 24.4991 26.4574 23.7778 26.4574Z"> </path> <path d="M14.8265 26.441C14.0924 26.441 13.2371 26.6795 12.6626 26.3786C12.0092 26.0372 12.3781 25.0644 12.246 24.378C11.1154 18.5324 6.6849 14.5497 0.74755 14.1001C0.217135 14.0615 -0.0104482 13.9422 0.0134113 13.3659C0.0519536 12.1454 0.0482829 10.9213 0.0134113 9.69524C-0.00127145 9.14464 0.196946 9.03268 0.703502 9.04736C9.21217 9.27128 16.5994 16.2511 17.2804 24.7231C17.418 26.4446 17.418 26.4446 15.6579 26.4446H14.832L14.8265 26.441Z"> </path> <path d="M3.58928 26.4555C2.64447 26.4618 1.73584 26.0925 1.06329 25.4289C0.39073 24.7653 0.00933763 23.8617 0.0030097 22.9169C-0.00331824 21.9721 0.365937 21.0635 1.02954 20.3909C1.69315 19.7184 2.59675 19.337 3.54156 19.3306C4.48637 19.3243 5.39499 19.6936 6.06755 20.3572C6.7401 21.0208 7.1215 21.9244 7.12782 22.8692C7.13415 23.814 6.7649 24.7226 6.10129 25.3952C5.43768 26.0677 4.53409 26.4491 3.58928 26.4555Z"> </path> </svg> <span class="usa-sr-only">NCBI RSS feed</span> </a> </div> </div> <div data-testid="gridContainer" class="grid-container ncbi-footer__container"> <div class="grid-row ncbi-footer__main-content-container" data-testid="grid"> <div class="ncbi-footer__column"> <p class="ncbi-footer__circled-icons-heading"> Connect with NLM </p> <div class="ncbi-footer__circled-icons-list"> <a href=https://twitter.com/nlm_nih class="ncbi-footer__social-icon ncbi-footer__social-icon--circled" target="_blank" rel="noreferrer noopener"> <svg width="32" height="32" viewBox="0 0 40 40" fill="none" xmlns="http://www.w3.org/2000/svg" focusable="false" aria-hidden="true"> <path d="m6.067 8 10.81 13.9L6 33.2h4.2l8.4-9.1 7.068 9.1H34L22.8 18.5 31.9 8h-3.5l-7.7 8.4L14.401 8H6.067Zm3.6 1.734h3.266l16.8 21.732H26.57L9.668 9.734Z"> </path> </svg> <span class="usa-sr-only">NLM on X (formerly known as Twitter)</span> </a> <a href=https://www.facebook.com/nationallibraryofmedicine class="ncbi-footer__social-icon ncbi-footer__social-icon--circled" target="_blank" rel="noreferrer noopener"> <svg width="13" height="24" viewBox="0 0 13 24" fill="none" xmlns="http://www.w3.org/2000/svg" focusable="false" aria-hidden="true"> <path d="M4.11371 23.1369C4.11371 23.082 4.11371 23.0294 4.11371 22.9745V12.9411H0.817305C0.6709 12.9411 0.670898 12.9411 0.670898 12.8016C0.670898 11.564 0.670898 10.3287 0.670898 9.09341C0.670898 8.97903 0.705213 8.95158 0.815017 8.95158C1.8673 8.95158 2.91959 8.95158 3.97417 8.95158H4.12057V8.83263C4.12057 7.8055 4.12057 6.7738 4.12057 5.74897C4.1264 4.92595 4.31387 4.11437 4.66959 3.37217C5.12916 2.38246 5.94651 1.60353 6.95717 1.1921C7.64827 0.905008 8.3913 0.764035 9.13953 0.778051C10.0019 0.791777 10.8644 0.830666 11.7268 0.860404C11.8869 0.860404 12.047 0.894717 12.2072 0.90158C12.2964 0.90158 12.3261 0.940469 12.3261 1.02968C12.3261 1.5421 12.3261 2.05452 12.3261 2.56465C12.3261 3.16857 12.3261 3.7725 12.3261 4.37642C12.3261 4.48165 12.2964 4.51367 12.1912 4.51138C11.5369 4.51138 10.8804 4.51138 10.2261 4.51138C9.92772 4.51814 9.63058 4.5526 9.33855 4.61433C9.08125 4.6617 8.84537 4.78881 8.66431 4.97766C8.48326 5.16652 8.3662 5.40755 8.32972 5.66661C8.28476 5.89271 8.26027 6.1224 8.25652 6.35289C8.25652 7.19014 8.25652 8.02969 8.25652 8.86923C8.25652 8.89439 8.25652 8.91955 8.25652 8.95615H12.0219C12.1797 8.95615 12.182 8.95616 12.1614 9.10714C12.0768 9.76596 11.9876 10.4248 11.9029 11.0813C11.8312 11.6319 11.7626 12.1824 11.697 12.733C11.6719 12.9434 11.6787 12.9434 11.4683 12.9434H8.26338V22.899C8.26338 22.979 8.26338 23.0591 8.26338 23.1392L4.11371 23.1369Z"> </path> </svg> <span class="usa-sr-only">NLM on Facebook</span> </a> <a href=https://www.youtube.com/user/NLMNIH class="ncbi-footer__social-icon ncbi-footer__social-icon--circled" target="_blank" rel="noreferrer noopener"> <svg width="21" height="15" viewBox="0 0 21 15" fill="none" xmlns="http://www.w3.org/2000/svg" focusable="false" aria-hidden="true"> <path d="M19.2561 1.47914C18.9016 1.15888 18.5699 0.957569 17.2271 0.834039C15.5503 0.678484 13.2787 0.655608 11.563 0.65332H9.43556C7.71987 0.65332 5.4483 0.678484 3.77151 0.834039C2.43098 0.957569 2.097 1.15888 1.74242 1.47914C0.813665 2.32097 0.619221 4.62685 0.598633 6.89384C0.598633 7.31781 0.598633 7.74101 0.598633 8.16345C0.626084 10.4121 0.827391 12.686 1.74242 13.521C2.097 13.8412 2.4287 14.0425 3.77151 14.1661C5.4483 14.3216 7.71987 14.3445 9.43556 14.3468H11.563C13.2787 14.3468 15.5503 14.3216 17.2271 14.1661C18.5676 14.0425 18.9016 13.8412 19.2561 13.521C20.1712 12.6929 20.3725 10.451 20.3999 8.22064C20.3999 7.74025 20.3999 7.25986 20.3999 6.77946C20.3725 4.54907 20.1689 2.30724 19.2561 1.47914ZM8.55942 10.5311V4.65201L13.5601 7.50005L8.55942 10.5311Z" fill="white" /> </svg> <span class="usa-sr-only">NLM on YouTube</span> </a> </div> </div> <address class="ncbi-footer__address ncbi-footer__column"> <p> <a class="usa-link usa-link--external" href="https://www.google.com/maps/place/8600+Rockville+Pike,+Bethesda,+MD+20894/%4038.9959508, -77.101021,17z/data%3D!3m1!4b1!4m5!3m4!1s0x89b7c95e25765ddb%3A0x19156f88b27635b8!8m2!3d38.9959508! 4d-77.0988323" rel="noopener noreferrer" target="_blank">National Library of Medicine <br/> 8600 Rockville Pike<br/> Bethesda, MD 20894</a> </p> </address> <ul class="usa-list usa-list--unstyled ncbi-footer__vertical-list ncbi-footer__column"> <li class="ncbi-footer__vertical-list-item"> <a href="https://www.nlm.nih.gov/web_policies.html" class="usa-link usa-link--alt ncbi-footer__link" > Web Policies </a> </li> <li class="ncbi-footer__vertical-list-item"> <a href="https://www.nih.gov/institutes-nih/nih-office-director/office-communications-public-liaison/freedom-information-act-office" class="usa-link usa-link--alt ncbi-footer__link" > FOIA </a> </li> <li class="ncbi-footer__vertical-list-item"> <a href="https://www.hhs.gov/vulnerability-disclosure-policy/index.html" class="usa-link usa-link--external usa-link--alt ncbi-footer__link" rel="noreferrer noopener" target='_blank' > HHS Vulnerability Disclosure </a> </li> </ul> <ul class="usa-list usa-list--unstyled ncbi-footer__vertical-list ncbi-footer__column"> <li class="ncbi-footer__vertical-list-item"> <a href="https://support.nlm.nih.gov/" class="usa-link usa-link--alt ncbi-footer__link" > Help </a> </li> <li class="ncbi-footer__vertical-list-item"> <a href="https://www.nlm.nih.gov/accessibility.html" class="usa-link usa-link--alt ncbi-footer__link" > Accessibility </a> </li> <li class="ncbi-footer__vertical-list-item"> <a href="https://www.nlm.nih.gov/careers/careers.html" class="usa-link usa-link--alt ncbi-footer__link" > Careers </a> </li> </ul> </div> <div class="grid-row grid-col-12" data-testid="grid"> <ul class="ncbi-footer__bottom-links-list"> <li class="ncbi-footer__bottom-list-item"> <a href="https://www.nlm.nih.gov/" class="usa-link usa-link--alt ncbi-footer__link" > NLM </a> </li> <li class="ncbi-footer__bottom-list-item"> <a href="https://www.nih.gov/" class="usa-link usa-link--alt ncbi-footer__link" > NIH </a> </li> <li class="ncbi-footer__bottom-list-item"> <a href="https://www.hhs.gov/" class="usa-link usa-link--external usa-link--alt ncbi-footer__link" rel="noreferrer noopener" target='_blank' > HHS </a> </li> <li class="ncbi-footer__bottom-list-item"> <a href="https://www.usa.gov/" class="usa-link usa-link--external usa-link--alt ncbi-footer__link" rel="noreferrer noopener" target='_blank' > USA.gov </a> </li> </ul> </div> </div> </footer> <script type="text/javascript" src="https://cdn.ncbi.nlm.nih.gov/core/pinger/pinger.js"> </script> <button class="back-to-top" data-ga-category="pagination" data-ga-action="back_to_top"> <label>Back to Top</label> <svg class="usa-icon order-0" aria-hidden="true" focusable="false" role="img"> <use xlink:href="/static/img/sprite.svg#arrow_upward"></use> </svg> </button> <script src="https://code.jquery.com/jquery-3.5.0.min.js" integrity="sha256-xNzN2a4ltkB44Mc/Jz3pT4iU1cmeR0FkXs4pru/JxaQ=" crossorigin="anonymous"> </script> <script type="text/javascript">var exports = {};</script> <script src="/static/CACHE/js/output.13b077bc3ffd.js"></script> <script type="application/javascript"> window.ncbi = window.ncbi || {}; window.ncbi.pmc = window.ncbi.pmc || {}; window.ncbi.pmc.options = { logLevel: 'INFO', staticEndpoint: '/static/', citeCookieName: 'pmc-cf', }; </script> <script type="module" crossorigin="" src="/static/assets/base-9bea7450.js"></script> <script type="module" crossorigin="" src="/static/assets/article-722d91a2.js"></script> <script type="module" crossorigin="" src="/static/assets/math-3a787fba.js"></script> </body> </html>