CINXE.COM

<!DOCTYPE html><html lang="en-US"><head><title>Just a moment...</title><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"><meta http-equiv="X-UA-Compatible" content="IE=Edge"><meta name="robots" content="noindex,nofollow"><meta name="viewport" content="width=device-width,initial-scale=1"><style>*{box-sizing:border-box;margin:0;padding:0}html{line-height:1.15;-webkit-text-size-adjust:100%;color:#313131;font-family:system-ui,-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,Helvetica Neue,Arial,Noto Sans,sans-serif,Apple Color Emoji,Segoe UI Emoji,Segoe UI Symbol,Noto Color Emoji}body{display:flex;flex-direction:column;height:100vh;min-height:100vh}.main-content{margin:8rem auto;max-width:60rem;padding-left:1.5rem}@media (width <= 720px){.main-content{margin-top:4rem}}.h2{font-size:1.5rem;font-weight:500;line-height:2.25rem}@media (width <= 720px){.h2{font-size:1.25rem;line-height:1.5rem}}#challenge-error-text{background-image:url(data:image/svg+xml;base64,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);background-repeat:no-repeat;background-size:contain;padding-left:34px}@media (prefers-color-scheme:dark){body{background-color:#222;color:#d9d9d9}}</style><meta http-equiv="refresh" content="390"></head><body class="no-js"><div class="main-wrapper" role="main"><div class="main-content"><noscript><div class="h2"><span id="challenge-error-text">Enable JavaScript and cookies to continue</span></div></noscript></div></div><script>(function(){window._cf_chl_opt={cvId: '3',cZone: "publications.waset.org",cType: 'managed',cRay: '91a3567879229d0e',cH: '1YH9E9VmZiaGcyhJ1DiXVGdzqkRlBlhOQ04bNEDifgk-1740944131-1.2.1.1-SqJNaISOLdwV97ZBALVQRzn__TkAyEypfpvRiL4VgxbRP9nNmATBL7r7Ur4e0MEi',cUPMDTk: "\/search?q=PHWR&__cf_chl_tk=jeYstUvQLjG2VlrImcy9HkSlMxo5iabrJdExF_pxTvc-1740944131-1.0.1.1-8oxN2H2tFsYUE7mQfjJYKsqkq2Xcb9OO.TRJ9oEkSd0",cFPWv: 'b',cITimeS: '1740944131',cTTimeMs: '1000',cMTimeMs: '390000',cTplC: 0,cTplV: 5,cTplB: 'cf',cK: "",fa: "\/search?q=PHWR&__cf_chl_f_tk=jeYstUvQLjG2VlrImcy9HkSlMxo5iabrJdExF_pxTvc-1740944131-1.0.1.1-8oxN2H2tFsYUE7mQfjJYKsqkq2Xcb9OO.TRJ9oEkSd0",md: "73wWVHUa4FXCMThwaSoXuLtKzSLWdyUoHAvmLwb8QGA-1740944131-1.2.1.1-ljcvwCvS1FqKDH2Mmc6qTvaI2FqX60_oxitJE2lZ5SwCAkewM.TkolwU0Agex114PqBN7hu5Q6f8bKzT0pFKhLhqlBimLWC41eRgiqEpSdZJ5eKB6Pu_Q_A6STK9YfYRwqDy4GbwekJ5UeIiXZSSeDbhN8zCrN9lf33jpwBThLCXt8gbkeseGIeSqJUqZ5MJyIm1Ma6TRAQj.6G.i5Tt__gYds0BrGY7P3yC2XOzBBwR7Prl6fCQmymGc1.wHaYVvwaDWLldUe.8kZgw6HcwjXHDeXNDFYWlCSxDho2UfwopIw6blNSwHT.EcY_6b3ldBo1CIcgGxoy0cPM1I3ZSHiUq_9mQ9AARTlFN9ihMHNtn6PRgl_YU4zVBJzxLDq1aWOP917xkT_lNKPiaN6GbXXbEBup7fK_6wRMQ4xs5o454xWayLSE4ec8akMS81dB1.SLZhiENXk9B.IZAa_8uxldS7M6iJaB7TALLFHTA5bYlZKd4kSONBPyQPz4VIybhM3UymB76kDOx6DQKnQ4cL596w3RYEr8wlN4H10mNJdvlebryy8qW0A3eUOq9fiIhqL92xag.5FKdgETTkEVAESnQQAPuxddLGBZ5IqVIEeKXD3ZPAAxCdU2M6IgyBQEy3KsjRGs08m.t94Up6BfYsQc91mRxJ0K41vmcbmPp0np3JVENKART7cP9XKhreZK0QYaXMRgm3hcp_PC4MDco2WniywwYLJdbzcXofGrAlcSd8yDHUciSoccBsfjco9XZHqVLpDXGsQGQyzss4sQilBqCtb_5xA.CMGfGKPoHerBsJ91vTMcskXqnZAJMg1wEcPZl2ctEzx3fdO9FSOhcZgsLIh0TXdRftrBSlw_4c_ffBec3H4Xpw2VneBXGCp6YQZGzhC7ckx.XbfgNeq36kwTvLlGOA1TcdxcPPfaU3xoKeNjdA0xkzr_yFv9yWfznrdrywypaRA2Ior5ucpb_W3gGe1epbihA9C9Jwh535PTRVfVyNmflU4I8Qh0cEzz1opJQ1V3DyMtFVtSNQr2P5unTi.cVqwO5u3Yi.yHG0d4.zdqEbFJHFpwTvUNkpLcdBTTQ1FeG_bHjFa_7zNvi6Ygluvf0kF0CrQn_z2LZnsFFjQsB4HdDMTvnWu2s6DSqSPlv5__hrUfU_ac6I0HihFpF4s82.tC.o7HUPl9HHyp3F8SZK1t_iPQlt3I97ksrHg.LrQOpJGLn5lJ6bAqwTw",mdrd: "capqFuQH_6m70HuS_AzgznTsAVBhmzT7wBfoOBCZfK8-1740944131-1.2.1.1-PmP4WigvUH9bnOVthN2rPrFa0jff0K_3P5be5OPnqvuYQMz9hcGH9UdEwTm6_UfaUfLbGWByKX3REIR5MgkqyI94yfYpsT7KYoKUEdpnIlUcqrhanJfMQvLdCxN44BtrHUxmj3sOEgTIDE8.neM_vYAl7HlvfrmM8dQ2DnJ8YfWxPbDNJlW8j_pOEf1cW65p5XXE0Dh9_h.s0zy0b20ijsgpovdaW6Hmde2ucAekhkcznXFUV1MT9BhwSHZQu9D4GubymuX0UGzSsTzL6ILPnh8dNgn2WewC8vIW68qqigZUDcWzzlZxBsTx2MDhe9Pm2qkQy77x3XQwelVmNN2slqiiQzMDRrvmBJd_Dt6VuT6YfAS3Abztd8OMg99mG.rPuqlQfjEALBMcUnxX9GfahiuXd3.ZLVNe7IwvxLS8sWuGZ2afU7FsZDB0K4CBLosUsEc7UVsBzRd_4qT6jig3R_b3iFItRWAsVCeKZjyT1aKZVtyGJTNV6dqgNbJ9pCuonpGcH0rqDg6_V8Z6.RK_rl.ehdkFWwFjU4ldTMA0yynfwzhlZtn4NY9uaORVS09b.fjLyIZvhzzQiI3e_MvduWD3KtdtSMXxZirhFKXcbq2MBAb92mJ6Hg28R1XtqvCAi7Zjz1oFsMDpO9vxduRnZrYlOxPaO0JfMcs_aOE5u9twFh5vpi0sSYG1XwcdVmlO_1GkjLeegEu2zkkTU1GLR_Ik6J8Ooqni63lFG7h8IDy.4Gdb_IMnlHxZr0EoMnv.v9ITITYgX80V8yqkKUz1m0ryiyHuCEcNWd.pqBu6biwIEv0KWlRM1Rsut0yfdnz.VzmRl4xANduP.CqfYFANBISxeSjEbtNzWLA3oIkIzrv2mufRdHfVMLsxhR65Mf2m.bDos.ErOMzMIQtQ4tXsY0L1T7SAz0VrefpLbjNaNCD_RerGLvBFsJ3C9tPIWWmW7xMV3L2mjANOKOWAD1h4mAjKDf_MrimGTHngHIgkFxERY6SggNL_PcclKeR6jQYK_VVPSm844Fn5w_jSdyrNtgkViLKubk0lWmZsLzRqYSwo4Ix1UR8iGxj6BJdQCBcJ4WNfqqZTYLSKo9Si8NoZ8jUCQC4_WV4X9kc0.XqKBkdV9C2hXdPbIwIXeXikTS1_lvJ7CTTzgy5XUwaVOqEMYGBmHOwa9jZylqg0ag33FzRD0AzDCOuL5.vBoE7.RcV2pB_JsjD.lSdVFcW12LzfskZluh.0vkrkhYaiyp5jPflSRG8ITc0sfQfhgiahM7cKVR7cxIoiKCjqPDYcvJc5fca5WDWxos5Zch4zwfB9P8qvUi1EVeWzLmBPinFqt4vcFRVcK0CdFuo5jm.nmEjFN5A67h7Z3mkhQRVkdrPlubZdrq.rDK9p5QB5FtxkiACKGXVdn7Bzouy65YMgBPQW48dksmfu2S4iiqtZmKVTUhaZU9CYHR0IPeOcc3MkGRaq.e43aHBdkeVX3Trrvkcy_rH3vK.udmrmCObgcRGcW2vw.7qKCABqWwkrxaH6tIvdqOdNs8UTVo4oeXIySK4c10P0C87uXmgadrrd1AhUwJsHA5i5sOiaI3YjYbk3VniufdM61sxjyiP9PpciBTkyzPC3HBd7OPyyS5hctbaBVcnyMSf0YCOeVf85kdsSkce.2mk6V4BQ9lHe3PkYPme_Vk0eDUMQZOyABAkazARtOZiwSa6COHTeNL.H5hTNN2aGLEu90rbgTpFJkJre51j.56k7gU3c696gmXNcLfsOlNIstIQqYag4y4ml9dtgAVgjC_PJud.NV_l32lwpcmEysPWJtOF9feWulLKquCgdIGhyKYEdygepFrs9EkHDu.UEX2IMciE_WEqbi2GHB9Yl21k0r_KKvYJBa43h0jVJbmo0aYW1knDM92IJNI7Fvy63DitI1bcTVOELZC52hpOF5NYIcWg6z1tQS3kUOgTfzoAE2qwhk4quwM_M6nCLBu_lNP92nO0GFYWVDtvlNKyOZw"};var cpo = document.createElement('script');cpo.src = '/cdn-cgi/challenge-platform/h/b/orchestrate/chl_page/v1?ray=91a3567879229d0e';window._cf_chl_opt.cOgUHash = location.hash === '' && location.href.indexOf('#') !== -1 ? '#' : location.hash;window._cf_chl_opt.cOgUQuery = location.search === '' && location.href.slice(0, location.href.length - window._cf_chl_opt.cOgUHash.length).indexOf('?') !== -1 ? '?' : location.search;if (window.history && window.history.replaceState) {var ogU = location.pathname + window._cf_chl_opt.cOgUQuery + window._cf_chl_opt.cOgUHash;history.replaceState(null, null, "\/search?q=PHWR&__cf_chl_rt_tk=jeYstUvQLjG2VlrImcy9HkSlMxo5iabrJdExF_pxTvc-1740944131-1.0.1.1-8oxN2H2tFsYUE7mQfjJYKsqkq2Xcb9OO.TRJ9oEkSd0" + window._cf_chl_opt.cOgUHash);cpo.onload = function() {history.replaceState(null, null, ogU);}}document.getElementsByTagName('head')[0].appendChild(cpo);}());</script></body></html>