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class="card-body"><strong>Frequency:</strong> Monthly</div> </div> </div> <div class="col-sm-3"> <div class="card"> <div class="card-body"><strong>Edition:</strong> International</div> </div> </div> <div class="col-sm-3"> <div class="card"> <div class="card-body"><strong>Paper Count:</strong> 658</div> </div> </div> </div> <h1 class="mt-3 mb-3 text-center" style="font-size:1.6rem;">Search results for: echo chamber</h1> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">658</span> Acoustic Echo Cancellation Using Different Adaptive Algorithms</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Hamid%20Sharif">Hamid Sharif</a>, <a href="https://publications.waset.org/abstracts/search?q=Nazish%20Saleem%20Abbas"> Nazish Saleem Abbas</a>, <a href="https://publications.waset.org/abstracts/search?q=Muhammad%20Haris%20Jamil"> Muhammad Haris Jamil</a> </p> <p class="card-text"><strong>Abstract:</strong></p> An adaptive filter is a filter that self-adjusts its transfer function according to an optimization algorithm driven by an error signal. Because of the complexity of the optimization algorithms, most adaptive filters are digital filters. Adaptive filtering constitutes one of the core technologies in digital signal processing and finds numerous application areas in science as well as in industry. Adaptive filtering techniques are used in a wide range of applications, including adaptive noise cancellation and echo cancellation. Acoustic echo cancellation is a common occurrence in today’s telecommunication systems. The signal interference caused by acoustic echo is distracting to both users and causes a reduction in the quality of the communication. In this paper, we review different techniques of adaptive filtering to reduce this unwanted echo. In this paper, we see the behavior of techniques and algorithms of adaptive filtering like Least Mean Square (LMS), Normalized Least Mean Square (NLMS), Variable Step-Size Least Mean Square (VSLMS), Variable Step-Size Normalized Least Mean Square (VSNLMS), New Varying Step Size LMS Algorithm (NVSSLMS) and Recursive Least Square (RLS) algorithms to reduce this unwanted echo, to increase communication quality. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=adaptive%20acoustic" title="adaptive acoustic">adaptive acoustic</a>, <a href="https://publications.waset.org/abstracts/search?q=echo%20cancellation" title=" echo cancellation"> echo cancellation</a>, <a href="https://publications.waset.org/abstracts/search?q=LMS%20algorithm" title=" LMS algorithm"> LMS algorithm</a>, <a href="https://publications.waset.org/abstracts/search?q=adaptive%20filter" title=" adaptive filter"> adaptive filter</a>, <a href="https://publications.waset.org/abstracts/search?q=normalized%20least%20mean%20square%20%28NLMS%29" title=" normalized least mean square (NLMS)"> normalized least mean square (NLMS)</a>, <a href="https://publications.waset.org/abstracts/search?q=variable%20step-size%20least%20mean%20square%20%28VSLMS%29" title=" variable step-size least mean square (VSLMS)"> variable step-size least mean square (VSLMS)</a> </p> <a href="https://publications.waset.org/abstracts/167766/acoustic-echo-cancellation-using-different-adaptive-algorithms" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/167766.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">84</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">657</span> Fundamental Research Dissension between Hot and Cold Chamber High Pressure Die Casting</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Sahil%20Kumar">Sahil Kumar</a>, <a href="https://publications.waset.org/abstracts/search?q=Surinder%20Pal"> Surinder Pal</a>, <a href="https://publications.waset.org/abstracts/search?q=Rahul%20Kapoor"> Rahul Kapoor</a> </p> <p class="card-text"><strong>Abstract:</strong></p> This paper is focused on to define the basic difference between hot and cold chamber high pressure die casting process which is not fully defined in a research before paper which we have studied. The pressure die casting is basically defined into two types (1) Hot chamber Die Casting (2) Cold chamber Die Casting. Cold chamber die casting is used for casting alloys that require high pressure and have a high melting temperature, such as brass, aluminum, magnesium, copper based alloys and other high melting point nonferrous alloys. Hot chamber die casting is suitable for casting zinc, tin, lead, and low melting point alloys. In hot chamber die casting machine, the molten metal is an integral pan of the machine. It mainly consists of hot chamber and gooseneck type metal container made of cast iron. This machine is mainly used for low melting alloys and alloys of metals like zinc, lead etc. Metals and alloys having a high melting point and those which are having an affinity for iron cannot be cast by this machine, which could otherwise attack the shot sleeve and damage the machine. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=hot%20chamber%20die%20casting" title="hot chamber die casting">hot chamber die casting</a>, <a href="https://publications.waset.org/abstracts/search?q=cold%20chamber%20die%20casting" title=" cold chamber die casting"> cold chamber die casting</a>, <a href="https://publications.waset.org/abstracts/search?q=metals%20and%20alloys" title=" metals and alloys"> metals and alloys</a>, <a href="https://publications.waset.org/abstracts/search?q=casting%20technology" title=" casting technology"> casting technology</a> </p> <a href="https://publications.waset.org/abstracts/25342/fundamental-research-dissension-between-hot-and-cold-chamber-high-pressure-die-casting" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/25342.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">624</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">656</span> Environmentally Adaptive Acoustic Echo Suppression for Barge-in Speech Recognition</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Jong%20Han%20Joo">Jong Han Joo</a>, <a href="https://publications.waset.org/abstracts/search?q=Jung%20Hoon%20Lee"> Jung Hoon Lee</a>, <a href="https://publications.waset.org/abstracts/search?q=Young%20Sun%20Kim"> Young Sun Kim</a>, <a href="https://publications.waset.org/abstracts/search?q=Jae%20Young%20Kang"> Jae Young Kang</a>, <a href="https://publications.waset.org/abstracts/search?q=Seung%20Ho%20Choi"> Seung Ho Choi</a> </p> <p class="card-text"><strong>Abstract:</strong></p> In this study, we propose a novel technique for acoustic echo suppression (AES) during speech recognition under barge-in conditions. Conventional AES methods based on spectral subtraction apply fixed weights to the estimated echo path transfer function (EPTF) at the current signal segment and to the EPTF estimated until the previous time interval. We propose a new approach that adaptively updates weight parameters in response to abrupt changes in the acoustic environment due to background noises or double-talk. Furthermore, we devised a voice activity detector and an initial time-delay estimator for barge-in speech recognition in communication networks. The initial time delay is estimated using log-spectral distance measure, as well as cross-correlation coefficients. The experimental results show that the developed techniques can be successfully applied in barge-in speech recognition systems. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=acoustic%20echo%20suppression" title="acoustic echo suppression">acoustic echo suppression</a>, <a href="https://publications.waset.org/abstracts/search?q=barge-in" title=" barge-in"> barge-in</a>, <a href="https://publications.waset.org/abstracts/search?q=speech%20recognition" title=" speech recognition"> speech recognition</a>, <a href="https://publications.waset.org/abstracts/search?q=echo%20path%20transfer%20function" title=" echo path transfer function"> echo path transfer function</a>, <a href="https://publications.waset.org/abstracts/search?q=initial%20delay%20estimator" title=" initial delay estimator"> initial delay estimator</a>, <a href="https://publications.waset.org/abstracts/search?q=voice%20activity%20detector" title=" voice activity detector"> voice activity detector</a> </p> <a href="https://publications.waset.org/abstracts/17151/environmentally-adaptive-acoustic-echo-suppression-for-barge-in-speech-recognition" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/17151.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">377</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">655</span> Conjugate Heat Transfer Analysis of a Combustion Chamber using ANSYS Computational Fluid Dynamics to Estimate the Thermocouple Positioning in a Chamber Wall</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Muzna%20Tariq">Muzna Tariq</a>, <a href="https://publications.waset.org/abstracts/search?q=Ihtzaz%20Qamar"> Ihtzaz Qamar</a> </p> <p class="card-text"><strong>Abstract:</strong></p> In most engineering cases, the working temperatures inside a combustion chamber are high enough that they lie beyond the operational range of thermocouples. Furthermore, design and manufacturing limitations restrict the use of internal thermocouples in many applications. Heat transfer inside a combustion chamber is caused due to interaction of the post-combustion hot fluid with the chamber wall. Heat transfer that involves an interaction between the fluid and solid is categorized as Conjugate Heat Transfer (CHT). Therefore, to satisfy the needs of CHT, CHT Analysis is performed by using ANSYS CFD tool to estimate theoretically precise thermocouple positions at the combustion chamber wall where excessive temperatures (beyond thermocouple range) can be avoided. In accordance with these Computational Fluid Dynamics (CFD) results, a combustion chamber is designed, and a prototype is manufactured with multiple thermocouple ports positioned at the specified distances so that the temperature of hot gases can be measured on the chamber wall where the temperatures do not exceed the thermocouple working range. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=computational%20fluid%20dynamics" title="computational fluid dynamics">computational fluid dynamics</a>, <a href="https://publications.waset.org/abstracts/search?q=conduction" title=" conduction"> conduction</a>, <a href="https://publications.waset.org/abstracts/search?q=conjugate%20heat%20transfer" title=" conjugate heat transfer"> conjugate heat transfer</a>, <a href="https://publications.waset.org/abstracts/search?q=convection" title=" convection"> convection</a>, <a href="https://publications.waset.org/abstracts/search?q=fluid%20flow" title=" fluid flow"> fluid flow</a>, <a href="https://publications.waset.org/abstracts/search?q=thermocouples" title=" thermocouples "> thermocouples </a> </p> <a href="https://publications.waset.org/abstracts/132074/conjugate-heat-transfer-analysis-of-a-combustion-chamber-using-ansys-computational-fluid-dynamics-to-estimate-the-thermocouple-positioning-in-a-chamber-wall" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/132074.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">154</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">654</span> Comparison Analysis of Multi-Channel Echo Cancellation Using Adaptive Filters</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Sahar%20Mobeen">Sahar Mobeen</a>, <a href="https://publications.waset.org/abstracts/search?q=Anam%20Rafique"> Anam Rafique</a>, <a href="https://publications.waset.org/abstracts/search?q=Irum%20Baig"> Irum Baig</a> </p> <p class="card-text"><strong>Abstract:</strong></p> Acoustic echo cancellation in multichannel is a system identification application. In real time environment, signal changes very rapidly which required adaptive algorithms such as Least Mean Square (LMS), Leaky Least Mean Square (LLMS), Normalized Least Mean square (NLMS) and average (AFA) having high convergence rate and stable. LMS and NLMS are widely used adaptive algorithm due to less computational complexity and AFA used of its high convergence rate. This research is based on comparison of acoustic echo (generated in a room) cancellation thorough LMS, LLMS, NLMS, AFA and newly proposed average normalized leaky least mean square (ANLLMS) adaptive filters. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=LMS" title="LMS">LMS</a>, <a href="https://publications.waset.org/abstracts/search?q=LLMS" title=" LLMS"> LLMS</a>, <a href="https://publications.waset.org/abstracts/search?q=NLMS" title=" NLMS"> NLMS</a>, <a href="https://publications.waset.org/abstracts/search?q=AFA" title=" AFA"> AFA</a>, <a href="https://publications.waset.org/abstracts/search?q=ANLLMS" title=" ANLLMS"> ANLLMS</a> </p> <a href="https://publications.waset.org/abstracts/28829/comparison-analysis-of-multi-channel-echo-cancellation-using-adaptive-filters" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/28829.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">573</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">653</span> A Hybrid Combustion Chamber Design for Diesel Engines</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=R.%20Gopakumar">R. Gopakumar</a>, <a href="https://publications.waset.org/abstracts/search?q=G.%20Nagarajan"> G. Nagarajan</a> </p> <p class="card-text"><strong>Abstract:</strong></p> Both DI and IDI systems possess inherent advantages as well as disadvantages. The objective of the present work is to obtain maximum advantages of both systems by implementing a hybrid design. A hybrid combustion chamber design consists of two combustion chambers viz., the main combustion chamber and an auxiliary combustion chamber. A fuel injector supplies major quantity of fuel to the auxiliary chamber. Due to the increased swirl motion in auxiliary chamber, mixing becomes more efficient which contributes to reduction in soot/particulate emissions. Also, by increasing the fuel injection pressure, NOx emissions can be reduced. The main objective of the hybrid combustion chamber design is to merge the positive features of both DI and IDI combustion chamber designs, which provides increased swirl motion and improved thermal efficiency. Due to the efficient utilization of fuel, low specific fuel consumption can be ensured. This system also aids in increasing the power output for same compression ratio and injection timing as compared with the conventional combustion chamber designs. The present system also reduces heat transfer and fluid dynamic losses which are encountered in IDI diesel engines. Since the losses are reduced, overall efficiency of the engine increases. It also minimizes the combustion noise and NOx emissions in conventional DI diesel engines. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=DI" title="DI">DI</a>, <a href="https://publications.waset.org/abstracts/search?q=IDI" title=" IDI"> IDI</a>, <a href="https://publications.waset.org/abstracts/search?q=hybrid%20combustion" title=" hybrid combustion"> hybrid combustion</a>, <a href="https://publications.waset.org/abstracts/search?q=diesel%20engines" title=" diesel engines"> diesel engines</a> </p> <a href="https://publications.waset.org/abstracts/10858/a-hybrid-combustion-chamber-design-for-diesel-engines" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/10858.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">543</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">652</span> The Influence of the Moving Speeds of DNA Droplet on Polymerase Chain Reaction</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Jyh%20Jyh%20Chen">Jyh Jyh Chen</a>, <a href="https://publications.waset.org/abstracts/search?q=Fu%20H.%20Yang"> Fu H. Yang</a>, <a href="https://publications.waset.org/abstracts/search?q=Chen%20W.%20Wang"> Chen W. Wang</a>, <a href="https://publications.waset.org/abstracts/search?q=Yu%20M.%20Lin"> Yu M. Lin</a> </p> <p class="card-text"><strong>Abstract:</strong></p> In this work, a reaction chamber is reciprocated among three temperature regions by using an oscillatory thermal cycling machine. Three cartridge heaters are collocated to heat three aluminum blocks in order to achieve PCR requirements in the reaction chamber. The effects of various chamber moving speeds among different temperature regions on the chamber temperature profiles are presented. To solve the evaporation effect of the sample in the PCR experiment, the mineral oil and the cover lid are used. The influences of various extension times on DNA amplification are also demonstrated. The target fragments of the amplification are 385-bp and 420-bp. The results show when the forward speed is set at 6 mm/s and the backward speed is 2.4 mm/s, the temperature required for the experiment can be achieved. It is successful to perform the amplification of DNA fragments in our device. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=oscillatory" title="oscillatory">oscillatory</a>, <a href="https://publications.waset.org/abstracts/search?q=polymerase%20chain%20reaction" title=" polymerase chain reaction"> polymerase chain reaction</a>, <a href="https://publications.waset.org/abstracts/search?q=reaction%20chamber" title=" reaction chamber"> reaction chamber</a>, <a href="https://publications.waset.org/abstracts/search?q=thermal%20cycling%20machine" title=" thermal cycling machine"> thermal cycling machine</a> </p> <a href="https://publications.waset.org/abstracts/64588/the-influence-of-the-moving-speeds-of-dna-droplet-on-polymerase-chain-reaction" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/64588.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">534</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">651</span> Combustion Chamber Sizing for Energy Recovery from Furnace Process Gas: Waste to Energy </h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Balram%20Panjwani">Balram Panjwani</a>, <a href="https://publications.waset.org/abstracts/search?q=Bernd%20Wittgens"> Bernd Wittgens</a>, <a href="https://publications.waset.org/abstracts/search?q=Jan%20Erik%20Olsen"> Jan Erik Olsen</a>, <a href="https://publications.waset.org/abstracts/search?q=Stein%20Tore%20Johansen"> Stein Tore Johansen</a> </p> <p class="card-text"><strong>Abstract:</strong></p> The Norwegian ferroalloy industry is a world leader in sustainable production of ferrosilicon, silicon and manganese alloys with the lowest global specific energy consumption. One of the byproducts during the metal reduction process is energy rich off-gas and usually this energy is not harnessed. A novel concept for sustainable energy recovery from ferroalloy off-gas is discussed. The concept is founded on the idea of introducing a combustion chamber in the off-gas section in which energy rich off-gas mainly consisting of CO will be combusted. This will provide an additional degree of freedom for optimizing energy recovery. A well-controlled and high off-gas temperature will assure a significant increase in energy recovery and reduction of emissions to the atmosphere. Design and operation of the combustion chamber depend on many parameters, including the total power capacity of the combustion chamber, sufficient residence time for combusting the complex Poly Aromatic Hydrocarbon (PAH), NOx, as well as converting other potential pollutants. The design criteria for the combustion chamber have been identified and discussed and sizing of the combustion chamber has been carried out considering these design criteria. Computational Fluid Dynamics (CFD) has been utilized extensively for sizing the combustion chamber. The results from our CFD simulations of the flow in the combustion chamber and exploring different off-gas fuel composition are presented. In brief, the paper covers all aspect which impacts the sizing of the combustion chamber, including insulation thickness, choice of insulating material, heat transfer through extended surfaces, multi-staging and secondary air injection. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=CFD" title="CFD">CFD</a>, <a href="https://publications.waset.org/abstracts/search?q=combustion%20chamber" title=" combustion chamber"> combustion chamber</a>, <a href="https://publications.waset.org/abstracts/search?q=arc%20furnace" title=" arc furnace"> arc furnace</a>, <a href="https://publications.waset.org/abstracts/search?q=energy%20recovery" title=" energy recovery"> energy recovery</a> </p> <a href="https://publications.waset.org/abstracts/33818/combustion-chamber-sizing-for-energy-recovery-from-furnace-process-gas-waste-to-energy" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/33818.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">325</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">650</span> Wall Heat Flux Mapping in Liquid Rocket Combustion Chamber with Different Jet Impingement Angles</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=O.%20S.%20Pradeep">O. S. Pradeep</a>, <a href="https://publications.waset.org/abstracts/search?q=S.%20Vigneshwaran"> S. Vigneshwaran</a>, <a href="https://publications.waset.org/abstracts/search?q=K.%20Praveen%20Kumar"> K. Praveen Kumar</a>, <a href="https://publications.waset.org/abstracts/search?q=K.%20Jeyendran"> K. Jeyendran</a>, <a href="https://publications.waset.org/abstracts/search?q=V.%20R.%20Sanal%20Kumar"> V. R. Sanal Kumar</a> </p> <p class="card-text"><strong>Abstract:</strong></p> The influence of injector attitude on wall heat flux plays an important role in predicting the start-up transient and also determining the combustion chamber wall durability of liquid rockets. In this paper comprehensive numerical studies have been carried out on an idealized liquid rocket combustion chamber to examine the transient wall heat flux during its start-up transient at different injector attitude. Numerical simulations have been carried out with the help of a validated 2d axisymmetric, double precision, pressure-based, transient, species transport, SST k-omega model with laminar finite rate model for governing turbulent-chemistry interaction for four cases with different jet intersection angles, viz., 0<sup>o</sup>, 30<sup>o</sup>, 45<sup>o</sup>, and 60<sup>o</sup>. We concluded that the jets intersection angle is having a bearing on the time and location of the maximum wall-heat flux zone of the liquid rocket combustion chamber during the start-up transient. We also concluded that the wall heat flux mapping in liquid rocket combustion chamber during the start-up transient is a meaningful objective for the chamber wall material selection and the lucrative design optimization of the combustion chamber for improving the payload capability of the rocket.   <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=combustion%20chamber" title="combustion chamber">combustion chamber</a>, <a href="https://publications.waset.org/abstracts/search?q=injector" title=" injector"> injector</a>, <a href="https://publications.waset.org/abstracts/search?q=liquid%20rocket" title=" liquid rocket"> liquid rocket</a>, <a href="https://publications.waset.org/abstracts/search?q=rocket%20engine%20wall%20heat%20flux" title=" rocket engine wall heat flux"> rocket engine wall heat flux</a> </p> <a href="https://publications.waset.org/abstracts/62084/wall-heat-flux-mapping-in-liquid-rocket-combustion-chamber-with-different-jet-impingement-angles" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/62084.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">492</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">649</span> Analysis Of Non-uniform Characteristics Of Small Underwater Targets Based On Clustering</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Tianyang%20Xu">Tianyang Xu</a> </p> <p class="card-text"><strong>Abstract:</strong></p> Small underwater targets generally have a non-centrosymmetric geometry, and the acoustic scattering field of the target has spatial inhomogeneity under active sonar detection conditions. In view of the above problems, this paper takes the hemispherical cylindrical shell as the research object, and considers the angle continuity implied in the echo characteristics, and proposes a cluster-driven research method for the non-uniform characteristics of target echo angle. First, the target echo features are extracted, and feature vectors are constructed. Secondly, the t-SNE algorithm is used to improve the internal connection of the feature vector in the low-dimensional feature space and to construct the visual feature space. Finally, the implicit angular relationship between echo features is extracted under unsupervised condition by cluster analysis. The reconstruction results of the local geometric structure of the target corresponding to different categories show that the method can effectively divide the angle interval of the local structure of the target according to the natural acoustic scattering characteristics of the target. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=underwater%20target%3B" title="underwater target;">underwater target;</a>, <a href="https://publications.waset.org/abstracts/search?q=non-uniform%20characteristics%3B" title=" non-uniform characteristics;"> non-uniform characteristics;</a>, <a href="https://publications.waset.org/abstracts/search?q=cluster-driven%20method%3B" title=" cluster-driven method;"> cluster-driven method;</a>, <a href="https://publications.waset.org/abstracts/search?q=acoustic%20scattering%20characteristics" title=" acoustic scattering characteristics"> acoustic scattering characteristics</a> </p> <a href="https://publications.waset.org/abstracts/169602/analysis-of-non-uniform-characteristics-of-small-underwater-targets-based-on-clustering" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/169602.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">143</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">648</span> Bacterio-Algal Microbial Fuel Cells for Sustainable Power Production, Wastewater Treatment, and Desalination</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Ann%20D.%20Christy">Ann D. Christy</a>, <a href="https://publications.waset.org/abstracts/search?q=Beenish%20Saba"> Beenish Saba</a> </p> <p class="card-text"><strong>Abstract:</strong></p> The Microbial fuel Cell (MFC) is a successful integrated technology for power production and wastewater treatment. MFCs are recognized for their dual function, but research in this field is still ongoing to increase efficiency and power output. One such effort is successful integration of phototrophic and autotrophic microorganisms to create bacterio-algal MFCs for sustainable electricity production along with wastewater treatment and algal biomass production. An MFC is typically configured with an anaerobic anodic chamber containing exoelectrogenic microorganisms separated by a cation exchange membrane from an adjacent aerobic cathodic chamber. The two electrodes are connected by an external circuit. This conventional MFC can be converted into a phototrophic MFC by introducing photosynthetic microorganisms into the cathode chamber. This study examines adding a third desalination chamber to a two-chamber bacterio-algal MFC. Successful results have been observed from these three-chamber MFCs demonstrating wastewater treatment in the anodic chamber, phototrophic algal growth in the cathodic chamber, and desalination in the middle chamber. The present article will summarize successful results of the bacterio-algal fuel cells and offer insights about the mechanisms involved. Tables summarizing the input substrate along with optimized operational conditions and output performance in terms of power production and efficiencies of water and wastewater treatment will be presented. The negative impacts and challenges will be discussed, along with possible future research directions. Results suggest that the three chamber bacterio-algal desalination cell has potential as a feasible technology for power production, wastewater treatment and desalination, but it needs further investigation under optimized conditions. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=bacterio-algal%20MFC" title="bacterio-algal MFC">bacterio-algal MFC</a>, <a href="https://publications.waset.org/abstracts/search?q=three%20chamber" title=" three chamber"> three chamber</a>, <a href="https://publications.waset.org/abstracts/search?q=microbial%20fuel%20cell" title=" microbial fuel cell"> microbial fuel cell</a>, <a href="https://publications.waset.org/abstracts/search?q=wastewater%20treatment%20and%20desalination" title=" wastewater treatment and desalination"> wastewater treatment and desalination</a> </p> <a href="https://publications.waset.org/abstracts/14135/bacterio-algal-microbial-fuel-cells-for-sustainable-power-production-wastewater-treatment-and-desalination" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/14135.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">366</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">647</span> Thickness Measurement and Void Detection in Concrete Elements through Ultrasonic Pulse</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Leonel%20Lipa%20Cusi">Leonel Lipa Cusi</a>, <a href="https://publications.waset.org/abstracts/search?q=Enrique%20Nestor%20Pasquel%20Carbajal"> Enrique Nestor Pasquel Carbajal</a>, <a href="https://publications.waset.org/abstracts/search?q=Laura%20Marina%20Navarro%20Alvarado"> Laura Marina Navarro Alvarado</a>, <a href="https://publications.waset.org/abstracts/search?q=Jos%C3%A9%20Del%20%C3%81lamo%20Carazas"> José Del Álamo Carazas</a> </p> <p class="card-text"><strong>Abstract:</strong></p> This research analyses the accuracy of the ultrasound and the pulse echo ultrasound technic to find voids and to measure thickness of concrete elements. These mentioned air voids are simulated by polystyrene expanded and hollow containers of thin thickness made of plastic or cardboard of different sizes and shapes. These targets are distributed strategically inside concrete at different depths. For this research, a shear wave pulse echo ultrasonic device of 50 KHz is used to scan the concrete elements. Despite the small measurements of the concrete elements and because of voids’ size are near the half of the wavelength, pre and post processing steps like voltage, gain, SAFT, envelope and time compensation were made in order to improve imaging results. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=ultrasonic" title="ultrasonic">ultrasonic</a>, <a href="https://publications.waset.org/abstracts/search?q=concrete" title=" concrete"> concrete</a>, <a href="https://publications.waset.org/abstracts/search?q=thickness" title=" thickness"> thickness</a>, <a href="https://publications.waset.org/abstracts/search?q=pulse%20echo" title=" pulse echo"> pulse echo</a>, <a href="https://publications.waset.org/abstracts/search?q=void" title=" void"> void</a> </p> <a href="https://publications.waset.org/abstracts/68618/thickness-measurement-and-void-detection-in-concrete-elements-through-ultrasonic-pulse" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/68618.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">341</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">646</span> Performing a Chamber Theatre Adaptation of Nick Joaquin's 'the Summer Solstice'</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Allen%20B.%20Baylosis">Allen B. Baylosis</a> </p> <p class="card-text"><strong>Abstract:</strong></p> Chamber Theatre has been one of the least articulated staging devices in the field of theatre and performance studies. This creative exploratory-descriptive study responds to this gap by employing the staging technique in a Chamber Theatre production based on Nick Joaquin’s The Summer Solstice. Specifically, this study opts to understand three processes involved in the Chamber Theatre creative thesis production of The Summer Solstice as performance: performance of the theatre-maker, performance of the spect-actors, and performance of the spectators. For this purpose, the theatre-maker describes the creative process of transforming The Summer Solstice text to a Chamber Theatre production—from text to staging. The theatre-maker also analyzes the performers’ experiences and the spectators’ responses as they participate in a Chamber Theatre performance. In doing so, the theatre-maker collects qualitative data from seventeen (17) performers and qualitative feedback from twenty (20) spectators. For the mode of data analysis, this study employed Ranciere’s concept on the Emancipated Spectator (2008) and Schechner’s Performance Theory (1988). The study’s findings examine how the theatre-maker, the performers, and the spectators become distant viewers of their respective restored behavior performances. Through these viewed performances, this study implies that it is possible to ascertain a reasonable definition of purpose for Chamber Theatre. Hence, despite the existence of other modern staging devices in the field of theatre and performance studies, this study concludes that Chamber Theatre remains to be a relevant staging technique. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=adaptation%20of%20text" title="adaptation of text">adaptation of text</a>, <a href="https://publications.waset.org/abstracts/search?q=chamber%20theatre" title=" chamber theatre"> chamber theatre</a>, <a href="https://publications.waset.org/abstracts/search?q=experimental%20theater" title=" experimental theater"> experimental theater</a>, <a href="https://publications.waset.org/abstracts/search?q=oral%20interpretation" title=" oral interpretation"> oral interpretation</a> </p> <a href="https://publications.waset.org/abstracts/130931/performing-a-chamber-theatre-adaptation-of-nick-joaquins-the-summer-solstice" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/130931.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">163</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">645</span> A Measurement Device of Condensing Flow Rate, an Order of MilliGrams per Second</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Hee%20Joon%20Lee">Hee Joon Lee</a> </p> <p class="card-text"><strong>Abstract:</strong></p> There are many difficulties in measuring a small flow rate of an order of milli grams per minute (LPM) or less using a conventional flowmeter. Therefore, a flow meter with minimal loss and based on a new concept was designed as part of this paper. A chamber was manufactured with a level transmitter and an on-off control valve. When the level of the collected condensed water reaches the top of the chamber, the valve opens to allow the collected water to drain back into the tank. To allow the water to continue to drain when the signal is lost, the valve is held open for a few seconds by a time delay switch and then closed. After an examination, the condensing flow rate was successfully measured with the uncertainty of ±5.7% of the full scale for the chamber. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=chamber" title="chamber">chamber</a>, <a href="https://publications.waset.org/abstracts/search?q=condensation" title=" condensation"> condensation</a>, <a href="https://publications.waset.org/abstracts/search?q=flow%20meter" title=" flow meter"> flow meter</a>, <a href="https://publications.waset.org/abstracts/search?q=milli-grams" title=" milli-grams"> milli-grams</a> </p> <a href="https://publications.waset.org/abstracts/48842/a-measurement-device-of-condensing-flow-rate-an-order-of-milligrams-per-second" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/48842.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">288</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">644</span> Study of Acoustic Resonance of Model Liquid Rocket Combustion Chamber and Its Suppression</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Vimal%20O.%20Kumar">Vimal O. Kumar</a>, <a href="https://publications.waset.org/abstracts/search?q=C.%20K.%20Muthukumaran"> C. K. Muthukumaran</a>, <a href="https://publications.waset.org/abstracts/search?q=P.%20Rakesh"> P. Rakesh</a> </p> <p class="card-text"><strong>Abstract:</strong></p> Liquid rocket engine (LRE) combustion chamber is subjected to pressure oscillation during the combustion process. The combustion noise (acoustic noise) is a broad band, small amplitude, high frequency component pressure oscillation. They constitute only a minor fraction ( < 1%) of the entire combustion process. However, this high frequency oscillation is huge concern during the design phase of LRE combustion chamber as it would cause catastrophic failure of the chamber. Depends on the chamber geometry, certain frequencies form standing wave pattern, and they resonate with high amplitude and are known as Eigen modes. These Eigen modes could cause failures unless it is suppressed to be within safe limits. These modes are categorized into radial, tangential, and azimuthal modes, and their structure inside the combustion chamber is of interest to the researchers. In the present proposal, experimental as well as numerical simulation will be performed to obtain the frequency-amplitude characteristics of the model combustion chamber for different baffle configuration. The main objective of this study is to find effect of baffle configuration that would provide better suppression of acoustic modes. The experimental study aims at measuring the frequency amplitude characteristics at certain points in the chamber wall. The experimental measurement will be also used for scheme used in numerical simulation. In addition to experiments, numerical simulation would provide detailed structure of the Eigenmodes exhibited and their level of suppression with the aid of different baffle configurations. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=baffle" title="baffle">baffle</a>, <a href="https://publications.waset.org/abstracts/search?q=instability" title=" instability"> instability</a>, <a href="https://publications.waset.org/abstracts/search?q=liquid%20rocket%20engine" title=" liquid rocket engine"> liquid rocket engine</a>, <a href="https://publications.waset.org/abstracts/search?q=pressure%20response%20of%20chamber" title=" pressure response of chamber"> pressure response of chamber</a> </p> <a href="https://publications.waset.org/abstracts/129395/study-of-acoustic-resonance-of-model-liquid-rocket-combustion-chamber-and-its-suppression" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/129395.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">127</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">643</span> Estimation of Slab Depth, Column Size and Rebar Location of Concrete Specimen Using Impact Echo Method</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Y.%20T.%20Lee">Y. T. Lee</a>, <a href="https://publications.waset.org/abstracts/search?q=J.%20H.%20Na"> J. H. Na</a>, <a href="https://publications.waset.org/abstracts/search?q=S.%20H.%20Kim"> S. H. Kim</a>, <a href="https://publications.waset.org/abstracts/search?q=S.%20U.%20Hong"> S. U. Hong</a> </p> <p class="card-text"><strong>Abstract:</strong></p> In this study, an experimental research for estimation of slab depth, column size and location of rebar of concrete specimen is conducted using the Impact Echo Method (IE) based on stress wave among non-destructive test methods. Estimation of slab depth had total length of 1800×300 and 6 different depths including 150 mm, 180 mm, 210 mm, 240 mm, 270 mm and 300 mm. The concrete column specimen was manufactured by differentiating the size into 300×300×300 mm, 400×400×400 mm and 500×500×500 mm. In case of the specimen for estimation of rebar, rebar of ∅22 mm was used in a specimen of 300×370×200 and arranged at 130 mm and 150 mm from the top to the rebar top. As a result of error rate of slab depth was overall mean of 3.1%. Error rate of column size was overall mean of 1.7%. Mean error rate of rebar location was 1.72% for top, 1.19% for bottom and 1.5% for overall mean showing relative accuracy. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=impact%20echo%20method" title="impact echo method">impact echo method</a>, <a href="https://publications.waset.org/abstracts/search?q=estimation" title=" estimation"> estimation</a>, <a href="https://publications.waset.org/abstracts/search?q=slab%20depth" title=" slab depth"> slab depth</a>, <a href="https://publications.waset.org/abstracts/search?q=column%20size" title=" column size"> column size</a>, <a href="https://publications.waset.org/abstracts/search?q=rebar%20location" title=" rebar location"> rebar location</a>, <a href="https://publications.waset.org/abstracts/search?q=concrete" title=" concrete"> concrete</a> </p> <a href="https://publications.waset.org/abstracts/6106/estimation-of-slab-depth-column-size-and-rebar-location-of-concrete-specimen-using-impact-echo-method" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/6106.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">356</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">642</span> Power Generation through Water Vapour: An Approach of Using Sea/River/Lake Water as Renewable Energy Source</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Riad">Riad</a> </p> <p class="card-text"><strong>Abstract:</strong></p> As present world needs more and more energy in a low cost way, it needs to find out the optimal way of power generation. In the sense of low cost, renewable energy is one of the greatest sources of power generation. Water vapour of sea/river/lake can be used for power generation by using the greenhouse effect in a large flat type water chamber floating on the water surface. The water chamber will always be kept half filled. When water evaporates by sunlight, the high pressured gaseous water will be stored in the chamber. By passing through a pipe and by using aerodynamics it can be used for power generation. The water level of the chamber is controlled by some means. As a large amount of water evaporates, an estimation can be highlighted, approximately 3 to 4 thousand gallons of water evaporates from per acre of surface (this amount will be more by greenhouse effect). This large amount of gaseous water can be utilized for power generation by passing through a pipe. This method can be a source of power generation. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=renewable%20energy" title="renewable energy">renewable energy</a>, <a href="https://publications.waset.org/abstracts/search?q=greenhouse%20effect" title=" greenhouse effect"> greenhouse effect</a>, <a href="https://publications.waset.org/abstracts/search?q=water%20chamber" title=" water chamber"> water chamber</a>, <a href="https://publications.waset.org/abstracts/search?q=water%20vapour" title=" water vapour"> water vapour</a> </p> <a href="https://publications.waset.org/abstracts/63915/power-generation-through-water-vapour-an-approach-of-using-seariverlake-water-as-renewable-energy-source" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/63915.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">362</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">641</span> Performance of an Optical Readout Gas Chamber for Charged Particle Track </h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Jing%20Hu">Jing Hu</a>, <a href="https://publications.waset.org/abstracts/search?q=Xiaoping%20Ouyang"> Xiaoping Ouyang</a> </p> <p class="card-text"><strong>Abstract:</strong></p> We develop an optical readout gas chamber based on avalanche-induced scintillation for energetic charged particles track. The gas chamber is equipped with a Single Anode Wires (SAW) structure to produce intensive electric field when the measured particles are of low yield or even single. In the presence of an intensive electric field around the single anode, primary electrons, resulting from the incident charged particles when depositing the energy along the track, accelerate to the anode effectively and rapidly. For scintillation gasses, this avalanche of electrons induces multiplying photons comparing with the primary scintillation excited directly from particle energy loss. The electric field distribution for different shape of the SAW structure is analyzed, and finally, an optimal one is used to study the optical readout performance. Using CF4 gas and its mixture with the noble gas, the results indicate that the optical readout characteristics of the chamber are attractive for imaging. Moreover, images of particles track including single particle track from 5.485MeV alpha particles are successfully acquired. The track resolution is quite well for the reason that the electrons undergo less diffusion in the intensive electric field. With the simple and ingenious design, the optical readout gas chamber has a high sensitivity. Since neutrons can be converted to charged particles when scattering, this optical readout gas chamber can be applied to neutron measurement for dark matter, fusion research, and others. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=optical%20readout" title="optical readout">optical readout</a>, <a href="https://publications.waset.org/abstracts/search?q=gas%20chamber" title=" gas chamber"> gas chamber</a>, <a href="https://publications.waset.org/abstracts/search?q=charged%20particle%20track" title=" charged particle track"> charged particle track</a>, <a href="https://publications.waset.org/abstracts/search?q=avalanche-induced%20scintillation" title=" avalanche-induced scintillation"> avalanche-induced scintillation</a>, <a href="https://publications.waset.org/abstracts/search?q=neutron%20measurement" title=" neutron measurement"> neutron measurement</a> </p> <a href="https://publications.waset.org/abstracts/61618/performance-of-an-optical-readout-gas-chamber-for-charged-particle-track" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/61618.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">277</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">640</span> X-Ray Dosimetry by a Low-Cost Current Mode Ion Chamber</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Ava%20Zarif%20Sanayei">Ava Zarif Sanayei</a>, <a href="https://publications.waset.org/abstracts/search?q=Mustafa%20Farjad-Fard"> Mustafa Farjad-Fard</a>, <a href="https://publications.waset.org/abstracts/search?q=Mohammad-Reza%20Mohammadian-Behbahani"> Mohammad-Reza Mohammadian-Behbahani</a>, <a href="https://publications.waset.org/abstracts/search?q=Leyli%20Ebrahimi"> Leyli Ebrahimi</a>, <a href="https://publications.waset.org/abstracts/search?q=Sedigheh%20Sina"> Sedigheh Sina</a> </p> <p class="card-text"><strong>Abstract:</strong></p> The fabrication and testing of a low-cost air-filled ion chamber for X-ray dosimetry is studied. The chamber is made of a metal cylinder, a central wire, a BC517 Darlington transistor, a 9V DC battery, and a voltmeter in order to have a cost-effective means to measure the dose. The output current of the dosimeter is amplified by the transistor and then fed to the large internal resistance of the voltmeter, producing a readable voltage signal. The dose-response linearity of the ion chamber is evaluated for different exposure scenarios by the X-ray tube. kVp values 70, 90, and 120, and mAs up to 20 are considered. In all experiments, a solid-state dosimeter (Solidose 400, Elimpex Medizintechnik) is used as a reference device for chamber calibration. Each case of exposure is repeated three times, the voltmeter and Solidose readings are recorded, and the mean and standard deviation values are calculated. Then, the calibration curve, derived by plotting voltmeter readings against Solidose readings, provided a linear fit result for all tube kVps of 70, 90, and 120. A 99, 98, and 100% linear relationship, respectively, for kVp values 70, 90, and 120 are demonstrated. The study shows the feasibility of achieving acceptable dose measurements with a simplified setup. Further enhancements to the proposed setup include solutions for limiting the leakage current, optimizing chamber dimensions, utilizing electronic microcontrollers for dedicated data readout, and minimizing the impact of stray electromagnetic fields on the system. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=dosimetry" title="dosimetry">dosimetry</a>, <a href="https://publications.waset.org/abstracts/search?q=ion%20chamber" title=" ion chamber"> ion chamber</a>, <a href="https://publications.waset.org/abstracts/search?q=radiation%20detection" title=" radiation detection"> radiation detection</a>, <a href="https://publications.waset.org/abstracts/search?q=X-ray" title=" X-ray"> X-ray</a> </p> <a href="https://publications.waset.org/abstracts/181982/x-ray-dosimetry-by-a-low-cost-current-mode-ion-chamber" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/181982.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">89</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">639</span> Rethinking the Public Sphere: Group Polarization on Social Media</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Tianji%20Jiang">Tianji Jiang</a> </p> <p class="card-text"><strong>Abstract:</strong></p> Habermas' definition of public sphere is a classical and well-regarded theory of the formation of public opinions, laying the foundation for many researches on public opinions and public media. In recent decades, public media have been changing rapidly as social media are gaining increasing importance. However, the occurrence of group polarization on social media, which is a hot issue today, is challenging Habermas' theory of the public sphere. This article reviews the public sphere theory and studies group polarization and social media. It proposes ideas on how to understand group polarization within the public sphere and comes up with some suggestions and ideas to reduce polarization on social media. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=public%20sphere" title="public sphere">public sphere</a>, <a href="https://publications.waset.org/abstracts/search?q=social%20media" title=" social media"> social media</a>, <a href="https://publications.waset.org/abstracts/search?q=group%20polarization" title=" group polarization"> group polarization</a>, <a href="https://publications.waset.org/abstracts/search?q=echo%20chamber" title=" echo chamber"> echo chamber</a>, <a href="https://publications.waset.org/abstracts/search?q=public%20opinion" title=" public opinion"> public opinion</a> </p> <a href="https://publications.waset.org/abstracts/158010/rethinking-the-public-sphere-group-polarization-on-social-media" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/158010.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">116</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">638</span> Characterization of an Extrapolation Chamber for Dosimetry of Low Energy X-Ray Beams </h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Fernanda%20M.%20Bastos">Fernanda M. Bastos</a>, <a href="https://publications.waset.org/abstracts/search?q=Te%C3%B3genes%20A.%20da%20Silva"> Teógenes A. da Silva</a> </p> <p class="card-text"><strong>Abstract:</strong></p> Extrapolation chambers were designed to be used as primary standard dosimeter for measuring absorbed dose in a medium in beta radiation and low energy x-rays. The International Organization for Standardization established series of reference x-radiation for calibrating and determining the energy dependence of dosimeters that are to be reproduced in metrology laboratories. Standardization of the low energy x-ray beams with tube potential lower than 30 kV may be affected by the instrument used for dosimetry. In this work, parameters of a 23392 model PTW extrapolation chamber were determined aiming its use in low energy x-ray beams as a reference instrument. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=extrapolation%20chamber" title="extrapolation chamber">extrapolation chamber</a>, <a href="https://publications.waset.org/abstracts/search?q=low%20energy%20x-rays" title=" low energy x-rays"> low energy x-rays</a>, <a href="https://publications.waset.org/abstracts/search?q=x-ray%20dosimetry" title=" x-ray dosimetry"> x-ray dosimetry</a>, <a href="https://publications.waset.org/abstracts/search?q=X-ray%20metrology" title=" X-ray metrology"> X-ray metrology</a> </p> <a href="https://publications.waset.org/abstracts/54330/characterization-of-an-extrapolation-chamber-for-dosimetry-of-low-energy-x-ray-beams" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/54330.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">403</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">637</span> Classification of Echo Signals Based on Deep Learning</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Aisulu%20Tileukulova">Aisulu Tileukulova</a>, <a href="https://publications.waset.org/abstracts/search?q=Zhexebay%20Dauren"> Zhexebay Dauren</a> </p> <p class="card-text"><strong>Abstract:</strong></p> Radar plays an important role because it is widely used in civil and military fields. Target detection is one of the most important radar applications. The accuracy of detecting inconspicuous aerial objects in radar facilities is lower against the background of noise. Convolutional neural networks can be used to improve the recognition of this type of aerial object. The purpose of this work is to develop an algorithm for recognizing aerial objects using convolutional neural networks, as well as training a neural network. In this paper, the structure of a convolutional neural network (CNN) consists of different types of layers: 8 convolutional layers and 3 layers of a fully connected perceptron. ReLU is used as an activation function in convolutional layers, while the last layer uses softmax. It is necessary to form a data set for training a neural network in order to detect a target. We built a Confusion Matrix of the CNN model to measure the effectiveness of our model. The results showed that the accuracy when testing the model was 95.7%. Classification of echo signals using CNN shows high accuracy and significantly speeds up the process of predicting the target. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=radar" title="radar">radar</a>, <a href="https://publications.waset.org/abstracts/search?q=neural%20network" title=" neural network"> neural network</a>, <a href="https://publications.waset.org/abstracts/search?q=convolutional%20neural%20network" title=" convolutional neural network"> convolutional neural network</a>, <a href="https://publications.waset.org/abstracts/search?q=echo%20signals" title=" echo signals"> echo signals</a> </p> <a href="https://publications.waset.org/abstracts/147596/classification-of-echo-signals-based-on-deep-learning" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/147596.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">358</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">636</span> Combustion and Emission Characteristics in a Can-Type Combustion Chamber</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Selvakuma%20Kumaresh">Selvakuma Kumaresh</a>, <a href="https://publications.waset.org/abstracts/search?q=Man%20Young%20Kim"> Man Young Kim</a> </p> <p class="card-text"><strong>Abstract:</strong></p> Combustion phenomenon will be accomplished effectively by the development of low emission combustor. One of the significant factors influencing the entire Combustion process is the mixing between a swirling angular jet (Primary Air) and the non-swirling inner jet (fuel). To study this fundamental flow, the chamber had to be designed in such a manner that the combustion process to sustain itself in a continuous manner and the temperature of the products is sufficiently below the maximum working temperature in the turbine. This study is used to develop the effective combustion with low unburned combustion products by adopting the concept of high swirl flow and motility of holes in the secondary chamber. The proper selection of a swirler is needed to reduce emission which can be concluded from the emission of Nox and CO2. The capture of CO2 is necessary to mitigate CO2 emissions from natural gas. Thus the suppression of unburned gases is a meaningful objective for the development of high performance combustor without affecting turbine blade temperature. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=combustion" title="combustion">combustion</a>, <a href="https://publications.waset.org/abstracts/search?q=emission" title=" emission"> emission</a>, <a href="https://publications.waset.org/abstracts/search?q=can-type%20combustion%20chamber" title=" can-type combustion chamber"> can-type combustion chamber</a>, <a href="https://publications.waset.org/abstracts/search?q=CFD" title=" CFD"> CFD</a>, <a href="https://publications.waset.org/abstracts/search?q=motility%20of%20holes" title=" motility of holes"> motility of holes</a>, <a href="https://publications.waset.org/abstracts/search?q=swirl%20flow" title=" swirl flow"> swirl flow</a> </p> <a href="https://publications.waset.org/abstracts/11885/combustion-and-emission-characteristics-in-a-can-type-combustion-chamber" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/11885.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">380</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">635</span> Submarine Topography and Beach Survey of Gang-Neung Port in South Korea, Using Multi-Beam Echo Sounder and Shipborne Mobile Light Detection and Ranging System</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Won%20Hyuck%20Kim">Won Hyuck Kim</a>, <a href="https://publications.waset.org/abstracts/search?q=Chang%20Hwan%20Kim"> Chang Hwan Kim</a>, <a href="https://publications.waset.org/abstracts/search?q=Hyun%20Wook%20Kim"> Hyun Wook Kim</a>, <a href="https://publications.waset.org/abstracts/search?q=Myoung%20Hoon%20Lee"> Myoung Hoon Lee</a>, <a href="https://publications.waset.org/abstracts/search?q=Chan%20Hong%20Park"> Chan Hong Park</a>, <a href="https://publications.waset.org/abstracts/search?q=Hyeon%20Yeong%20Park"> Hyeon Yeong Park</a> </p> <p class="card-text"><strong>Abstract:</strong></p> We conducted submarine topography & beach survey from December 2015 and January 2016 using multi-beam echo sounder EM3001(Kongsberg corporation) & Shipborne Mobile LiDAR System. Our survey area were the Anmok beach in Gangneung, South Korea. We made Shipborne Mobile LiDAR System for these survey. Shipborne Mobile LiDAR System includes LiDAR (RIEGL LMS-420i), IMU ((Inertial Measurement Unit, MAGUS Inertial+) and RTKGNSS (Real Time Kinematic Global Navigation Satellite System, LEIAC GS 15 GS25) for beach's measurement, LiDAR's motion compensation & precise position. Shipborne Mobile LiDAR System scans beach on the movable vessel using the laser. We mounted Shipborne Mobile LiDAR System on the top of the vessel. Before beach survey, we conducted eight circles IMU calibration survey for stabilizing heading of IMU. This exploration should be as close as possible to the beach. But our vessel could not come closer to the beach because of latency objects in the water. At the same time, we conduct submarine topography survey using multi-beam echo sounder EM3001. A multi-beam echo sounder is a device observing and recording the submarine topography using sound wave. We mounted multi-beam echo sounder on left side of the vessel. We were equipped with a motion sensor, DGNSS (Differential Global Navigation Satellite System), and SV (Sound velocity) sensor for the vessel's motion compensation, vessel's position, and the velocity of sound of seawater. Shipborne Mobile LiDAR System was able to reduce the consuming time of beach survey rather than previous conventional methods of beach survey. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=Anmok" title="Anmok">Anmok</a>, <a href="https://publications.waset.org/abstracts/search?q=beach%20survey" title=" beach survey"> beach survey</a>, <a href="https://publications.waset.org/abstracts/search?q=Shipborne%20Mobile%20LiDAR%20System" title=" Shipborne Mobile LiDAR System"> Shipborne Mobile LiDAR System</a>, <a href="https://publications.waset.org/abstracts/search?q=submarine%20topography" title=" submarine topography"> submarine topography</a> </p> <a href="https://publications.waset.org/abstracts/65092/submarine-topography-and-beach-survey-of-gang-neung-port-in-south-korea-using-multi-beam-echo-sounder-and-shipborne-mobile-light-detection-and-ranging-system" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/65092.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">433</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">634</span> MRI R2* of Liver in an Animal Model</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Chiung-Yun%20Chang">Chiung-Yun Chang</a>, <a href="https://publications.waset.org/abstracts/search?q=Po-Chou%20Chen"> Po-Chou Chen</a>, <a href="https://publications.waset.org/abstracts/search?q=Jiun-Shiang%20Tzeng"> Jiun-Shiang Tzeng</a>, <a href="https://publications.waset.org/abstracts/search?q=Ka-Wai%20Mac"> Ka-Wai Mac</a>, <a href="https://publications.waset.org/abstracts/search?q=Chia-Chi%20Hsiao"> Chia-Chi Hsiao</a>, <a href="https://publications.waset.org/abstracts/search?q=Jo-Chi%20Jao"> Jo-Chi Jao</a> </p> <p class="card-text"><strong>Abstract:</strong></p> This study aimed to measure R2* relaxation rates in the liver of New Zealand White (NZW) rabbits. R2* relaxation rate has been widely used in various hepatic diseases for iron overload by quantifying iron contents in liver. R2* relaxation rate is defined as the reciprocal of T2* relaxation time and mainly depends on the composition of tissue. Different tissues would have different R2* relaxation rates. The signal intensity decay in Magnetic resonance imaging (MRI) may be characterized by R2* relaxation rates. In this study, a 1.5T GE Signa HDxt whole body MR scanner equipped with an 8-channel high resolution knee coil was used to observe R2* values in NZW rabbit’s liver and muscle. Eight healthy NZW rabbits weighted 2 ~ 2.5 kg were recruited. After anesthesia using Zoletil 50 and Rompun 2% mixture, the abdomen of rabbit was landmarked at the center of knee coil to perform 3-plane localizer scan using fast spoiled gradient echo (FSPGR) pulse sequence. Afterward, multi-planar fast gradient echo (MFGR) scans were performed with 8 various echo times (TEs) (2/4/6/8/10/12/14/16 ms) to acquire images for R2* calculations. Regions of interest (ROIs) at liver and muscle were measured using Advantage workstation. Finally, the R2* was obtained by a linear regression of ln(SI) on TE. The results showed that the longer the echo time, the smaller the signal intensity. The R2* values of liver and muscle were 44.8  10.9 s-1 and 37.4  9.5 s-1, respectively. It implies that the iron concentration of liver is higher than that of muscle. In conclusion, R2* is correlated with iron contents in tissue. The correlations between R2* and iron content in NZW rabbit might be valuable for further exploration. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=liver" title="liver">liver</a>, <a href="https://publications.waset.org/abstracts/search?q=magnetic%20resonance%20imaging" title=" magnetic resonance imaging"> magnetic resonance imaging</a>, <a href="https://publications.waset.org/abstracts/search?q=muscle" title=" muscle"> muscle</a>, <a href="https://publications.waset.org/abstracts/search?q=R2%2A%20relaxation%20rate" title=" R2* relaxation rate"> R2* relaxation rate</a> </p> <a href="https://publications.waset.org/abstracts/30632/mri-r2-of-liver-in-an-animal-model" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/30632.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">439</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">633</span> Optimization of Transmission Loss on a Series-Coupled Muffler by Taguchi Method</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Jing-Fung%20Lin">Jing-Fung Lin</a>, <a href="https://publications.waset.org/abstracts/search?q=Jer-Jia%20Sheu"> Jer-Jia Sheu</a> </p> <p class="card-text"><strong>Abstract:</strong></p> In this study, an approach has been developed for the noise reduction of a muffler. The transmission loss (TL) in the muffler is maximized by the use of a double-chamber muffler, and a baffle with a hole is inserted between chambers. Taguchi method is used to optimize the design for the acoustical performance of the muffler. The TL performance is evaluated by COMSOL software. The excellent parameter combination for the maximum TL is attained as high as 35.30 dB in a wide frequency range from 10 Hz to 1400 Hz. The influence sequence of four parameters on TL is determined by the range analysis. The effects of length and expansion ratio of the first chamber on TL performance for the excellent program were discussed. Comparisons of the TL results from different designs are made. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=acoustics" title="acoustics">acoustics</a>, <a href="https://publications.waset.org/abstracts/search?q=baffle" title=" baffle"> baffle</a>, <a href="https://publications.waset.org/abstracts/search?q=chamber" title=" chamber"> chamber</a>, <a href="https://publications.waset.org/abstracts/search?q=muffler" title=" muffler"> muffler</a>, <a href="https://publications.waset.org/abstracts/search?q=Taguchi%20method" title=" Taguchi method"> Taguchi method</a>, <a href="https://publications.waset.org/abstracts/search?q=transmission%20loss" title=" transmission loss"> transmission loss</a> </p> <a href="https://publications.waset.org/abstracts/150143/optimization-of-transmission-loss-on-a-series-coupled-muffler-by-taguchi-method" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/150143.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">120</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">632</span> Transient Level in the Surge Chamber at the Robert-bourassa Generating Station</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Maryam%20Kamali%20Nezhad">Maryam Kamali Nezhad</a> </p> <p class="card-text"><strong>Abstract:</strong></p> The Robert-Bourassa development (LG-2), the first to be built on the Grande Rivière, comprises two sets of eight turbines- generator units each, the East and West powerhouses. Each powerhouse has two tailrace tunnels with an average length of about 1178 m. The LG-2A powerhouse houses 6 turbine-generator units. The water is discharged through two tailrace tunnels with a length of about 1330 m. The objective of this work, at RB (LG-2), is; 1) to establish a new maximum transient level in the surge chamber, 2) to define the new maximum equipment flow rate for the future turbine-generator units, 3) to ensure safe access to various intervention locations in the surge chamber. The transient levels under normal operating conditions at the RB plant were determined in 2001 by the Hydraulics Unit of HQE using the "Chamber" software. It is a one-dimensional mass oscillation calculation software; it is used to determine the variation of the water level in the equilibrium chamber located downstream of a power plant during the load shedding of the power plant units; it can also be used in the case of an equilibrium stack upstream of a power plant. The RB (LG-2) plant study is based on the theoretical nominal geometry of the chamber and the tailrace tunnels and the flow-level relationship at the outlet of the galleries established during design. The software is used in such a way that the results have an acceptable margin of safety, especially with respect to the maximum transient level (e.g., resumption of flow at an inopportune time), to take into account the turbulent and three-dimensional aspects of the actual flow in the chamber. Note that the transient levels depend on the water levels in the river and in the steady-state equilibrium chambers. These data are established in the HQP CRP database and updated from time to time. The maximum transient levels in the RB-East and RB-West powerhouses surge chamber were revised based on the latest update (set 4) of in-river rating curves and steady-state surge chamber water levels. The results of the revision were also used to update the technical advice on the operating conditions for the aforementioned surge chamber access while considering revisions to the calculated water levels. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=generating%20station" title="generating station">generating station</a>, <a href="https://publications.waset.org/abstracts/search?q=surge%20chamber" title=" surge chamber"> surge chamber</a>, <a href="https://publications.waset.org/abstracts/search?q=maximum%20transient%20level" title=" maximum transient level"> maximum transient level</a>, <a href="https://publications.waset.org/abstracts/search?q=hydroelectric%20power%20station" title=" hydroelectric power station"> hydroelectric power station</a>, <a href="https://publications.waset.org/abstracts/search?q=turbine-generator" title=" turbine-generator"> turbine-generator</a>, <a href="https://publications.waset.org/abstracts/search?q=reservoir" title=" reservoir"> reservoir</a> </p> <a href="https://publications.waset.org/abstracts/162729/transient-level-in-the-surge-chamber-at-the-robert-bourassa-generating-station" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/162729.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">91</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">631</span> Experimental Approach for Determining Hemi-Anechoic Characteristics of Engineering Acoustical Test Chambers</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Santiago%20Montoya-Ospina">Santiago Montoya-Ospina</a>, <a href="https://publications.waset.org/abstracts/search?q=Ra%C3%BAl%20E.%20Jim%C3%A9nez-Mej%C3%ADa"> Raúl E. Jiménez-Mejía</a>, <a href="https://publications.waset.org/abstracts/search?q=Rosa%20Elvira%20Correa%20Guti%C3%A9rrez"> Rosa Elvira Correa Gutiérrez</a> </p> <p class="card-text"><strong>Abstract:</strong></p> An experimental methodology is proposed for determining hemi-anechoic characteristics of an engineering acoustic room built at the facilities of Universidad Nacional de Colombia to evaluate the free-field conditions inside the chamber. Experimental results were compared with theoretical ones in both, the source and the sound propagation inside the chamber. Acoustic source was modeled by using monopole radiation pattern from punctual sources and the image method was considered for dealing with the reflective plane of the room, that means, the floor without insulation. Finite-difference time-domain (FDTD) method was implemented to calculate the sound pressure value at every spatial point of the chamber. Comparison between theoretical and experimental data yields to minimum error, giving satisfactory results for the hemi-anechoic characterization of the chamber. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=acoustic%20impedance" title="acoustic impedance">acoustic impedance</a>, <a href="https://publications.waset.org/abstracts/search?q=finite-difference%20time-domain" title=" finite-difference time-domain"> finite-difference time-domain</a>, <a href="https://publications.waset.org/abstracts/search?q=hemi-anechoic%20characterization" title=" hemi-anechoic characterization"> hemi-anechoic characterization</a> </p> <a href="https://publications.waset.org/abstracts/86159/experimental-approach-for-determining-hemi-anechoic-characteristics-of-engineering-acoustical-test-chambers" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/86159.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">169</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">630</span> Design of Low-Emission Catalytically Stabilized Combustion Chamber Concept</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Annapurna%20Basavaraju">Annapurna Basavaraju</a>, <a href="https://publications.waset.org/abstracts/search?q=Andreas%20Marn"> Andreas Marn</a>, <a href="https://publications.waset.org/abstracts/search?q=Franz%20Heitmeir"> Franz Heitmeir</a> </p> <p class="card-text"><strong>Abstract:</strong></p> The Advisory Council for Aeronautics Research in Europe (ACARE) is cognizant for the overall reduction of NOx emissions by 80% in its vision 2020. Moreover small turbo engines have higher fuel specific emissions compared to large engines due to their limited combustion chamber size. In order to fulfill these requirements, novel combustion concepts are essential. This motivates to carry out the research on the current state of art, catalytic stabilized combustion chamber using hydrogen in small jet engines which are designed and investigated both numerically and experimentally during this project. Catalytic combustion concepts can also be adopted for low caloric fuels and are therefore not constrained to only hydrogen. However, hydrogen has high heating value and has the major advantage of producing only the nitrogen oxides as pollutants during the combustion, thus eliminating the interest on other emissions such as Carbon monoxides etc. In the present work, the combustion chamber is designed based on the ‘Rich catalytic Lean burn’ concept. The experiments are conducted for the characteristic operating range of an existing engine. This engine has been tested successfully at Institute of Thermal Turbomachinery and Machine Dynamics (ITTM), Technical University Graz. One of the facts that the efficient combustion is a result of proper mixing of fuel-air mixture, considerable significance is given to the selection of appropriate mixer. This led to the design of three diverse configurations of mixers and is investigated experimentally and numerically. Subsequently the best mixer would be equipped in the main combustion chamber and used throughout the experimentation. Furthermore, temperatures and pressures would be recorded at various locations inside the combustion chamber and the exhaust emissions will also be analyzed. The instrumented combustion chamber would be inspected at the engine relevant inlet conditions for nine different sets of catalysts at the Hot Flow Test Facility (HFTF) of the institute. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=catalytic%20combustion" title="catalytic combustion">catalytic combustion</a>, <a href="https://publications.waset.org/abstracts/search?q=gas%20turbine" title=" gas turbine"> gas turbine</a>, <a href="https://publications.waset.org/abstracts/search?q=hydrogen" title=" hydrogen"> hydrogen</a>, <a href="https://publications.waset.org/abstracts/search?q=mixer" title=" mixer"> mixer</a>, <a href="https://publications.waset.org/abstracts/search?q=NOx%20emissions" title=" NOx emissions"> NOx emissions</a> </p> <a href="https://publications.waset.org/abstracts/71565/design-of-low-emission-catalytically-stabilized-combustion-chamber-concept" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/71565.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">309</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">629</span> Quality Evaluation of Backfill Grout in Tunnel Boring Machine Tail Void Using Impact-Echo (IE): Short-Time Fourier Transform (STFT) Numerical Analysis</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Ju-Young%20Choi">Ju-Young Choi</a>, <a href="https://publications.waset.org/abstracts/search?q=Ki-Il%20Song"> Ki-Il Song</a>, <a href="https://publications.waset.org/abstracts/search?q=Kyoung-Yul%20Kim"> Kyoung-Yul Kim</a> </p> <p class="card-text"><strong>Abstract:</strong></p> During Tunnel Boring Machine (TBM) tunnel excavation, backfill grout should be injected after the installation of segment lining to ensure the stability of the tunnel and to minimize ground deformation. If grouting is not sufficient to fill the gap between the segments and rock mass, hydraulic pressures occur in the void, which can negatively influence the stability of the tunnel. Recently the tendency to use TBM tunnelling method to replace the drill and blast(NATM) method is increasing. However, there are only a few studies of evaluation of backfill grout. This study evaluates the TBM tunnel backfill state using Impact-Echo(IE). 3-layers, segment-grout-rock mass, are simulated by FLAC 2D, FDM-based software. The signals obtained from numerical analysis and IE test are analyzed by Short-Time Fourier Transform(STFT) in time domain, frequency domain, and time-frequency domain. The result of this study can be used to evaluate the quality of backfill grouting in tail void. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=tunnel%20boring%20machine" title="tunnel boring machine">tunnel boring machine</a>, <a href="https://publications.waset.org/abstracts/search?q=backfill%20grout" title=" backfill grout"> backfill grout</a>, <a href="https://publications.waset.org/abstracts/search?q=impact-echo%20method" title=" impact-echo method"> impact-echo method</a>, <a href="https://publications.waset.org/abstracts/search?q=time-frequency%20domain%20analysis" title=" time-frequency domain analysis"> time-frequency domain analysis</a>, <a href="https://publications.waset.org/abstracts/search?q=finite%20difference%20method" title=" finite difference method"> finite difference method</a> </p> <a href="https://publications.waset.org/abstracts/53362/quality-evaluation-of-backfill-grout-in-tunnel-boring-machine-tail-void-using-impact-echo-ie-short-time-fourier-transform-stft-numerical-analysis" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/53362.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">273</span> </span> </div> </div> <ul class="pagination"> <li class="page-item disabled"><span class="page-link">&lsaquo;</span></li> <li class="page-item active"><span class="page-link">1</span></li> <li class="page-item"><a class="page-link" href="https://publications.waset.org/abstracts/search?q=echo%20chamber&page=2">2</a></li> <li class="page-item"><a class="page-link" href="https://publications.waset.org/abstracts/search?q=echo%20chamber&page=3">3</a></li> <li class="page-item"><a class="page-link" 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