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Articles 2491 - 2520 of 21777

Full-Text Articles in Engineering

Control Of High-Temperature Static And Transient Thermomechanical Behavior Of Simo Ductile Iron By Al Alloying, Semen Naumovich Lekakh, Catherine E. Johnson, L. Godlewski, Mei Li Feb 2022

Control Of High-Temperature Static And Transient Thermomechanical Behavior Of Simo Ductile Iron By Al Alloying, Semen Naumovich Lekakh, Catherine E. Johnson, L. Godlewski, Mei Li

Materials Science and Engineering Faculty Research & Creative Works

Silicon and molybdenum (SiMo) ductile iron is commonly used for exhaust manifolds because these components experience thermal cycling in oxidizing environment, which requires resistance to fatigue during transient thermomechanical loads. Previous studies have demonstrated that alloying elements, such as Al, to SiMo ductile iron reduces the amount of surface degradation during static high-temperature exposure. However, deterioration of sphericity of the graphite nodules and a decrease in ductility could affect the tendency of cracking during thermal cycling. In this article, the effect of Al alloying on static and transient thermomechanical behavior of SiMo ductile iron was investigated to optimize the amount …

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Dynamical Properties Of Environmental High-Performance Composites With Calcined Clay, Jingjie Wei, Wu Jian Long, Kamal Khayat, Biqin Dong, Liu Mei, Feng Xing Feb 2022

Dynamical Properties Of Environmental High-Performance Composites With Calcined Clay, Jingjie Wei, Wu Jian Long, Kamal Khayat, Biqin Dong, Liu Mei, Feng Xing

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Concrete structures may be exposed to dynamic loadings within short periods such as earthquakes and vehicles load, resulting in substantial damage to human life and property because of the collapse of concrete structures. The research achievements on dynamic properties of high-performance composites with LC3 (HPC-LC3) are limited, although dynamic loadings are commonly encountered in infrastructure. The study aims to develop a new-green concrete product (HPC-LC3) with high dynamical properties and promote its mass use in a vibration service environment by investigating dynamical properties of HPC-LC3. Dynamical properties of structure can be promoted at material level by means of enhancing the …

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A Detailed Hydrodynamic Study Of The Split-Plate Airlift Reactor By Using Non-Invasive Gamma-Ray Techniques, Laith S. Sabri, Abbas J. Sultan, Hasan Shakir Majdi, Shadha K. Jebur, Muthanna H. Al-Dahhan Feb 2022

A Detailed Hydrodynamic Study Of The Split-Plate Airlift Reactor By Using Non-Invasive Gamma-Ray Techniques, Laith S. Sabri, Abbas J. Sultan, Hasan Shakir Majdi, Shadha K. Jebur, Muthanna H. Al-Dahhan

Chemical and Biochemical Engineering Faculty Research & Creative Works

This study focused on detailed investigations of selected local hydrodynamics in split airlift reactor by using an unconventional measurements facility: computed tomography (CT) and radioactive particle tracking (RPT). The local distribution in a cross-sectional manner with its radial's profiles for gas holdup, liquid velocity flow field, shear stresses, and turbulent kinetic energy were studied under various gas velocity 1, 2 and 3 cm/s with various six axial level z = 12, 20, 40, 60, 90 and 112 cm. The distribution in gas-liquid phases in the whole split reactor column, the riser and downcomer sides, including their behavior at the top …

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Building Marginal Pattern Library With Unbiased Training Dataset For Enhancing Model-Free Load-Ed Mapping, Qiwei Zhang, Fangxing Li, Wei Feng, Xiaofei Wang, Linquan Bai, Rui Bo Feb 2022

Building Marginal Pattern Library With Unbiased Training Dataset For Enhancing Model-Free Load-Ed Mapping, Qiwei Zhang, Fangxing Li, Wei Feng, Xiaofei Wang, Linquan Bai, Rui Bo

Electrical and Computer Engineering Faculty Research & Creative Works

Input-output mapping for a given power system problem, such as loads versus economic dispatch (ED) results, has been demonstrated to be learnable through artificial intelligence (AI) techniques, including neural networks. However, the process of identifying and constructing a comprehensive dataset for the training of such input-output mapping remains a challenge to be solved. Conventionally, load samples are generated by a pre-defined distribution, and then ED is solved based on those load samples to form training datasets, but this paper demonstrates that such dataset generation is biased regarding load-ED mapping. The marginal unit and line congestion (i.e., marginal pattern) exhibit a …

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Geant4 Simulation For Radioactive Particle Tracking (Rpt) Technique, Ahmed A. Alghamdi, Thaar M. Aljuwaya, Abdullah S. Alomari, Muthanna H. Al-Dahhan Feb 2022

Geant4 Simulation For Radioactive Particle Tracking (Rpt) Technique, Ahmed A. Alghamdi, Thaar M. Aljuwaya, Abdullah S. Alomari, Muthanna H. Al-Dahhan

Chemical and Biochemical Engineering Faculty Research & Creative Works

In the past two decades, the radioactive particle tracking (RPT) measurement technique has been proven to visualize flow fields of most multiphase flow systems of industrial interest. The accuracy of RPT, and hence the data obtained, depend largely on the calibration process, which stands here as a basis for two subsequent processes: tracking and reconstruction. However, limitations in the RPT calibration process can be found in different experimental constrains and in assumptions made in the classical Monte Carlo approach used to simulate number of counts received by the detectors. Therefore, in this work, we applied a GEANT4-based Monte Carlo code …

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Laboratory Evaluation Of Placement Behavior Of Microgels For Conformance Control In Reservoirs Containing Superpermeable Channels, Yang Zhao, Baojun Bai Feb 2022

Laboratory Evaluation Of Placement Behavior Of Microgels For Conformance Control In Reservoirs Containing Superpermeable Channels, Yang Zhao, Baojun Bai

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Gel treatment has been proven an effective method to attack excessive water production in many mature oilfields. However, not all of the application projects have successful stories. The effectiveness of a gel treatment largely depends on the transport and placement behavior of gel materials in reservoirs to be treated. In this work, we carried out systematic studies to investigate the transport, placement, water-blocking ability, fluid diversion and sweep improvement, and matrix damage effect of micrometer-sized preformed particle gels (microgels) in reservoirs containing superpermeable (super-K) channels. The impact of the channel/matrix permeability contrast and the particle/pore size ratio in the channels …

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Setting Times Of Early-Age Mortars Determined From Evolution Curves Of Poisson’S Ratio, Bate Bate, Xiao Chen, Chao Chen, Hongyan Ma, Jianfeng Zhu, Junnan Cao, Jiakai Chen, Kamal Khayat, Shuai Zhang Feb 2022

Setting Times Of Early-Age Mortars Determined From Evolution Curves Of Poisson’S Ratio, Bate Bate, Xiao Chen, Chao Chen, Hongyan Ma, Jianfeng Zhu, Junnan Cao, Jiakai Chen, Kamal Khayat, Shuai Zhang

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Setting times, as the early-age properties of cement-based materials, are important properties to ensure the quality and long-term performance of engineering structures. To determine the initial and final setting times of cementitious materials, the compressive wave velocity and shear wave velocity of six early-age mortar samples were monitored. Their time evolution curves of Young's modulus, shear modulus, bulk modulus, and Poisson's ratio were then calculated and analyzed. The signature times of the derivatives of the Poisson's ratio evolution curves correlate well with the initial and final setting times, and the remarkably high coefficient of determination values relative to the data …

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Water Film Depth Prediction Model For Highly Textured Pavement Surface Drainage, Alireza Pourhassan, Ahmed A. Gheni, Mohamed Elgawady Feb 2022

Water Film Depth Prediction Model For Highly Textured Pavement Surface Drainage, Alireza Pourhassan, Ahmed A. Gheni, Mohamed Elgawady

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Water film depth (WFD) is an important factor for road traffic safety because of its direct connection with skid resistance, hydroplaning speed, and the tendency of splash and spray. Increasing the pavement macrotexture reduces WFD. However, existing models for WFD prediction have not been developed on highly textured surfaces such as chip seal. Furthermore, the rainfall intensities used for developing most of these models were relatively low, leaving no or low WFD on chip seal surfaces. To propose a WFD prediction model suitable for highly textured surfaces and to consider the effect of surface material type, an experimental study was …

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A Comprehensive Review Of In-Situ Polymer Gel Simulation For Conformance Control, Baojun Bai, Jianqiao Leng, Mingzhen Wei Feb 2022

A Comprehensive Review Of In-Situ Polymer Gel Simulation For Conformance Control, Baojun Bai, Jianqiao Leng, Mingzhen Wei

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Gel treatment has been widely applied in mature oilfields to improve sweep efficiency and control water production. Correct numerical simulation is of major importance to the optimization design and prediction of a successful gel treatment. However, there exist many problems in current simulation studies in published literature. This paper first presents a comprehensive review on the major factors that have been considered at different gelation stages during gel treatment, the models used in the commercial/in-house simulators, and current numerical simulation studies on both laboratory and field scales. Then we classify the current in-situ gel numerical simulation problems as 1, deficient …

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Setting Times Of Early-Age Mortars Determined From Evolution Curves Of Poisson’S Ratio, Bate Bate, Xiao Chen, Chao Chen, Hongyan Ma, Jianfeng Zhu, Junnan Cao, Jiakai Chen, Kamal Khayat, Shuai Zhang Feb 2022

Setting Times Of Early-Age Mortars Determined From Evolution Curves Of Poisson’S Ratio, Bate Bate, Xiao Chen, Chao Chen, Hongyan Ma, Jianfeng Zhu, Junnan Cao, Jiakai Chen, Kamal Khayat, Shuai Zhang

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Setting times, as the early-age properties of cement-based materials, are important properties to ensure the quality and long-term performance of engineering structures. To determine the initial and final setting times of cementitious materials, the compressive wave velocity and shear wave velocity of six early-age mortar samples were monitored. Their time evolution curves of Young's modulus, shear modulus, bulk modulus, and Poisson's ratio were then calculated and analyzed. The signature times of the derivatives of the Poisson's ratio evolution curves correlate well with the initial and final setting times, and the remarkably high coefficient of determination values relative to the data …

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Wellbore Integrity: An Integrated Experimental And Numerical Study To Investigate Pore Pressure Variation During Cement Hardening Under Downhole Conditions, Weicheng Zhang, Andreas Eckert, Steven Austin Hilgedick, Harvey Goodman, Meng Meng Feb 2022

Wellbore Integrity: An Integrated Experimental And Numerical Study To Investigate Pore Pressure Variation During Cement Hardening Under Downhole Conditions, Weicheng Zhang, Andreas Eckert, Steven Austin Hilgedick, Harvey Goodman, Meng Meng

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Understanding the cement hardening process and determining the development of the state of stress in the cement under specific downhole conditions are challenging but fundamental requirements to perform an accurate prediction of wellbore integrity. As an essential component of the state of stress, the temporal variation of cement pore pressure is a critical factor that affects the occurrence of cement failure. In this study, we present a novel laboratory setup to measure the cement pore pressure variation during hardening under representative downhole conditions, including the pressure, temperature, and water exchange between the cement and formation. The pore pressure measurements are …

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The Shepherd Mountain Iron Ore Deposit In Southeast Missouri, Usa – An Extension Of The Pilot Knob Magmatic-Hydrothermal Ore System: Evidence From Iron Oxide Chemistry, Bolorchimeg N. Tunnell, Marek Locmelis, Cheryl Seeger, Marilena Moroni, Sarah Dare, Ryan Mathur, Brandon Sullivan Feb 2022

The Shepherd Mountain Iron Ore Deposit In Southeast Missouri, Usa – An Extension Of The Pilot Knob Magmatic-Hydrothermal Ore System: Evidence From Iron Oxide Chemistry, Bolorchimeg N. Tunnell, Marek Locmelis, Cheryl Seeger, Marilena Moroni, Sarah Dare, Ryan Mathur, Brandon Sullivan

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

The Southeast Missouri Iron Metallogenic Province in the Midcontinent USA contains seven major and several minor IOA/IOCG-type deposits and a series of shallow vein-type deposits/prospects, all of which are spatially and temporally associated with early Mesoproterozoic (1500–1440 Ma) magmatism in the St. Francois Mountains terrane. One of the vein-type deposits is the Shepherd Mountain deposit, which consists of two northeast-trending ore veins dominated by magnetite and lesser amounts of hematite. Here we report the findings of a study that investigates the origin of the Shepherd Mountain deposit and a possible genetic link to the nearby (i.e., away) magmatic to magmatic-hydrothermal …

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Prediction Of Soil Water Content And Electrical Conductivity Using Random Forest Methods With Uav Multispectral And Ground-Coupled Geophysical Data, Yunyi Guan, Katherine R. Grote, Joel Schott, Kelsi Leverett Feb 2022

Prediction Of Soil Water Content And Electrical Conductivity Using Random Forest Methods With Uav Multispectral And Ground-Coupled Geophysical Data, Yunyi Guan, Katherine R. Grote, Joel Schott, Kelsi Leverett

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

The volumetric water content (VWC) of soil is a critical parameter in agriculture, as VWC strongly influences crop yield, provides nutrients to plants, and maintains the microbes that are needed for the biological health of the soil. Measuring VWC is difficult, as it is spatially and tempo-rally heterogeneous, and most agricultural producers use point measurements that cannot fully capture this parameter. Electrical conductivity (EC) is another soil parameter that is useful in agricul-ture, since it can be used to indicate soil salinity, soil texture, and plant nutrient availability. Soil EC is also very heterogeneous; measuring EC using conventional soil sampling …

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Experimental Study Of Transport Behavior Of Swellable Microgel Particles In Superpermeable Channels For Conformance Control, Yang Zhao, Baojun Bai Feb 2022

Experimental Study Of Transport Behavior Of Swellable Microgel Particles In Superpermeable Channels For Conformance Control, Yang Zhao, Baojun Bai

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Gel treatment is an effective way to attack excessive water production during oil development. The transport behavior of gel materials in reservoirs is of crucial importance to the effectiveness of gel treatments. The aim of this paper is investigating the transport behavior of swellable micrometer-sized preformed particle gels (PPGs, or microgels) through superpermeable (super-K) channels. Sandpacks with permeabilities ranging from 27 to 221 darcies were used to mimic the super-K channels. Multiple pressure sensors were applied along the sandpack models to monitor the propagation behavior of the microgels. The tested microgel particles could transport through the super-K channels, and a …

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A Low-Profile Fabry-Pérot Cavity Antenna Using Anisotropic Metasurface, Muhammad Yasir Jamal, Min Li, Kwan Lawrence Yeung, Xiaoqiang Li, Lijun Jiang, Tatsuo Itoh Feb 2022

A Low-Profile Fabry-Pérot Cavity Antenna Using Anisotropic Metasurface, Muhammad Yasir Jamal, Min Li, Kwan Lawrence Yeung, Xiaoqiang Li, Lijun Jiang, Tatsuo Itoh

Electrical and Computer Engineering Faculty Research & Creative Works

A Fabry-Pérot cavity (FPC) antenna utilizing a new cavity resonance phenomenon based on the polarization standing wave (PSW) is proposed. To produce PSW, two anisotropic metasurfaces acting as the handedness preserving mirror are designed as the two ends of the cavity. Such a cavity possesses a new resonant condition, i.e., the relative rotation angle and distance between two metasurfaces together determine its resonant frequency. Hence, in comparison to conventional FPC antennas, the proposed one possesses a lower profile height of around 0.125 wavelengths. The antenna concept is experimentally demonstrated for the 12 GHz X-band application. Measurement results agree well with …

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Resource Availability And Implications For The Development Of Plug‐In Electric Vehicles, Ona Egbue, Suzanna Long, Seong Dae Kim Feb 2022

Resource Availability And Implications For The Development Of Plug‐In Electric Vehicles, Ona Egbue, Suzanna Long, Seong Dae Kim

Engineering Management and Systems Engineering Faculty Research & Creative Works

Plug‐in electric vehicles (PEVs) have immense potential for reducing greenhouse gas emissions and dependence on fossil fuels, and for smart grid applications. Although a great deal of research is focused on technological limitations that affect PEV battery performance targets, a major and arguably equal concern is the constraint imposed by the finite availability of elements or resources used in the manufacture of PEV batteries. Availability of resources, such as lithium, for batteries is critical to the future of PEVs and is, therefore, a topic that needs attention. This study addresses the issues related to lithium availability and sustainability, particularly supply …

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Resource Availability And Implications For The Development Of Plug‐In Electric Vehicles, Ona Egbue, Suzanna Long, Seong Dae Kim Feb 2022

Resource Availability And Implications For The Development Of Plug‐In Electric Vehicles, Ona Egbue, Suzanna Long, Seong Dae Kim

Engineering Management and Systems Engineering Faculty Research & Creative Works

Plug‐in electric vehicles (PEVs) have immense potential for reducing greenhouse gas emissions and dependence on fossil fuels, and for smart grid applications. Although a great deal of research is focused on technological limitations that affect PEV battery performance targets, a major and arguably equal concern is the constraint imposed by the finite availability of elements or resources used in the manufacture of PEV batteries. Availability of resources, such as lithium, for batteries is critical to the future of PEVs and is, therefore, a topic that needs attention. This study addresses the issues related to lithium availability and sustainability, particularly supply …

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Geant4 Simulation For Radioactive Particle Tracking (Rpt) Technique, Ahmed A. Alghamdi, Thaar M. Aljuwaya, Abdullah S. Alomari, Muthanna H. Al-Dahhan Feb 2022

Geant4 Simulation For Radioactive Particle Tracking (Rpt) Technique, Ahmed A. Alghamdi, Thaar M. Aljuwaya, Abdullah S. Alomari, Muthanna H. Al-Dahhan

Chemical and Biochemical Engineering Faculty Research & Creative Works

In the past two decades, the radioactive particle tracking (RPT) measurement technique has been proven to visualize flow fields of most multiphase flow systems of industrial interest. The accuracy of RPT, and hence the data obtained, depend largely on the calibration process, which stands here as a basis for two subsequent processes: tracking and reconstruction. However, limitations in the RPT calibration process can be found in different experimental constrains and in assumptions made in the classical Monte Carlo approach used to simulate number of counts received by the detectors. Therefore, in this work, we applied a GEANT4-based Monte Carlo code …

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Flow Regimes In Gas-Solid Fluidized Beds Via Micro-Foil Heat Flux Sensor, Haidar Taofeeq, Sebastián Uribe, Muthanna H. Al-Dahhan Feb 2022

Flow Regimes In Gas-Solid Fluidized Beds Via Micro-Foil Heat Flux Sensor, Haidar Taofeeq, Sebastián Uribe, Muthanna H. Al-Dahhan

Chemical and Biochemical Engineering Faculty Research & Creative Works

The flow regime transitions in a gas-solid fluidized bed were studied for the first time using a micro-foil heat flux sensor. The time series of heat flux signals was analyzed by statistical and state space methods. The experimental measurements were performed in a lab-scale gas-solid fluidization column. Four different flow regimes, i.e., fixed-bed flow regime, bubbling-flow regime, slugging-flow regime, and turbulent-flow regime, and three intermediate transition velocities, i.e., minimum fluidizing velocity or minimum bubbling velocity, minimum slugging velocity, and minimum turbulent velocity, were successfully identified. The method based on the analysis of heat flux sensor measurements allowed to determine accurately …

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Effects Of Particle Size Distribution With Efficient Packing On Powder Flowability And Selective Laser Melting Process, Zachary Young, Minglei Qu, Meelap Michael Coday, Qilin Guo, Seyed Mohammad H. Hojjatzadeh, Luis I. Escano, Kamel Fezzaa, Lianyi Chen Feb 2022

Effects Of Particle Size Distribution With Efficient Packing On Powder Flowability And Selective Laser Melting Process, Zachary Young, Minglei Qu, Meelap Michael Coday, Qilin Guo, Seyed Mohammad H. Hojjatzadeh, Luis I. Escano, Kamel Fezzaa, Lianyi Chen

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The powder bed-based additive manufacturing (AM) process contains uncertainties in the powder spreading process and powder bed quality, leading to problems in repeatability and quality of the additively manufactured parts. This work focuses on identifying the uncertainty induced by particle size distribution (PSD) on powder flowability and the laser melting process, using Ti6Al4V as a model material. The flowability test results show that the effect of PSDs on flowability is not linear, rather the PSDs near dense packing ratios cause significant reductions in flowability (indicated by the increase in the avalanche angle and break energy of the powders measured by …

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Effects Of Particle Size Distribution With Efficient Packing On Powder Flowability And Selective Laser Melting Process, Zachary Young, Minglei Qu, Meelap Michael Coday, Qilin Guo, Seyed Mohammad H. Hojjatzadeh, Luis I. Escano, Kamel Fezzaa, Lianyi Chen Feb 2022

Effects Of Particle Size Distribution With Efficient Packing On Powder Flowability And Selective Laser Melting Process, Zachary Young, Minglei Qu, Meelap Michael Coday, Qilin Guo, Seyed Mohammad H. Hojjatzadeh, Luis I. Escano, Kamel Fezzaa, Lianyi Chen

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The powder bed-based additive manufacturing (AM) process contains uncertainties in the powder spreading process and powder bed quality, leading to problems in repeatability and quality of the additively manufactured parts. This work focuses on identifying the uncertainty induced by particle size distribution (PSD) on powder flowability and the laser melting process, using Ti6Al4V as a model material. The flowability test results show that the effect of PSDs on flowability is not linear, rather the PSDs near dense packing ratios cause significant reductions in flowability (indicated by the increase in the avalanche angle and break energy of the powders measured by …

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Data On The Validation To Determine The Material Thermal Properties Estimation Via A One-Dimensional Transient Convection Model, Lauren B. Tomanek, Daniel S. Stutts Feb 2022

Data On The Validation To Determine The Material Thermal Properties Estimation Via A One-Dimensional Transient Convection Model, Lauren B. Tomanek, Daniel S. Stutts

Mechanical and Aerospace Engineering Faculty Research & Creative Works

These data were acquired to estimate the parameters of a closed form solution of a one-dimensional transient convection heat diffusion PDE. The purpose was to demonstrate that the model could be used to determine the thermal conductivity. The system was tested for a wide range of thermal conductivity, 15-400 W/mK, in order to verify that the method was applicable for various materials. The data reported here refer to the study in the research articles, "Material Thermal Properties Estimation Via a One-Dimensional Transient Convection Model" [1] and "Influence of porosity on the thermal, electrical, and mechanical performance of selective laser melted …

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A Stub Equalizer For Bidirectional And Single-Ended Channels In Nand Memory Storage Device Systems, Taelim Song, Jongjoo Lee, Chulsoon Hwang Feb 2022

A Stub Equalizer For Bidirectional And Single-Ended Channels In Nand Memory Storage Device Systems, Taelim Song, Jongjoo Lee, Chulsoon Hwang

Electrical and Computer Engineering Faculty Research & Creative Works

In memory devices, such as solid-state drive, multitopology is used for interfaces where multiple memory packages are connected to a controller using a branched transmission line. Impedance mismatching caused by the branches and unwanted reflection from deactivated packages inevitably degrades signal quality, limiting the data rate of the interface. In this article, a simple stub equalizer is proposed to improve the data rate of the memory interface. An open-ended stub is placed between a transmitter and a receiver, and the length, impedance, and location of the stub line are determined to properly cancel the reflection from other branches. Parameters are …

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Efficient And Accurate Phase-Measurement Method For Core-Loss Characterization, Anfeng Huang, Jun Fan, Chulsoon Hwang Feb 2022

Efficient And Accurate Phase-Measurement Method For Core-Loss Characterization, Anfeng Huang, Jun Fan, Chulsoon Hwang

Electrical and Computer Engineering Faculty Research & Creative Works

Accurate core-loss characterization is essential to push the power density of power converters to their limits. However, existing core-loss measurement methods still have some limitations, such as a slow test speed and a complex probe calibration procedure. In particular, accurate phase-difference measurement is time-consuming because a fast Fourier transform analysis with a kHz-range frequency interval is typically applied to reduce the influence of noise. An automated measurement system for magnetic core-loss characterization is described in this paper. An accurate phase-detection block with programmable attenuators is developed to measure the phase difference between voltage and current waveforms. The proposed system considerably …

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Optimum Design Of Half Tunnels For Transportation In The Himalayas, Muhammad Zaka Emad, Muhammad Usman Khan, Muhammad Azeem Raza, Saqib Ahmad Saki, Muhammad Aijaz, Muhammad Usman Tahir Feb 2022

Optimum Design Of Half Tunnels For Transportation In The Himalayas, Muhammad Zaka Emad, Muhammad Usman Khan, Muhammad Azeem Raza, Saqib Ahmad Saki, Muhammad Aijaz, Muhammad Usman Tahir

Mining Engineering Faculty Research & Creative Works

Numerical modeling is a fine tool for the assessment of inaccessible zones or unforeseen conditions in geotechnical engineering. When modeling structures in rocks, the laboratory-determined properties must be factored as per rock mass classification. The joints present in rock mass can be utilized for assessment of wedges forming around the tunnels. Half tunnels or overhanging tunnels are constructed in steep rock slopes through slot cutting. This develops overhanging cliff in hard rocks that looked like a half tunnel. Half tunnels have advantage over conventional tunnels or open excavations as they require less excavation. The current construction practice of half tunnels …

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Novel Tri-Viscous Model To Simulate Pumping Of Flowable Concrete Through Characterization Of Lubrication Layer And Plug Zones, Tooran Tavangar, Masoud Hosseinpoor, Ammar Yahia, Kamal Khayat Feb 2022

Novel Tri-Viscous Model To Simulate Pumping Of Flowable Concrete Through Characterization Of Lubrication Layer And Plug Zones, Tooran Tavangar, Masoud Hosseinpoor, Ammar Yahia, Kamal Khayat

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

In this study, computational fluid dynamics (CFD) was employed to simulate the pipe flow of 18 self-consolidating and four highly workable concrete mixtures in a 30-m long pumping circuit. Pressure loss (ΔP) in 100- and 125-mm diameter (DP) pipelines was measured under low (1.2–6.2 l/s) and high (8.1–16.4 l/s) flow rates (Q). The numerical simulation was successfully carried out using a two-fluid model and a new variable-viscosity single-fluid approach, namely double-Bingham and tri-viscous models, respectively. The radial variation of rheological properties of the concrete across the pipe section, representing the plug flow, sheared concrete, and lubrication layer (LL) zones was …

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A Statistical Mimo Channel Model For Reconfigurable Intelligent Surface Assisted Wireless Communications, Baiping Xiong, Zaichen Zhang, Hao Jiang, Hongming Zhang, Jiangfan Zhang, Liang Wu, Jian Dang Feb 2022

A Statistical Mimo Channel Model For Reconfigurable Intelligent Surface Assisted Wireless Communications, Baiping Xiong, Zaichen Zhang, Hao Jiang, Hongming Zhang, Jiangfan Zhang, Liang Wu, Jian Dang

Electrical and Computer Engineering Faculty Research & Creative Works

Reconfigurable intelligent surface (RIS) consisting of a large number of programmable near-passive units has been a hot topic in wireless communications due to its capability in providing smart radio environments to enhance the communication performance. However, the existing research are mainly based on simplistic channel models, which will, in principle, lead to inaccurate analysis of the system performance. In this paper, we propose a general three-dimensional (3D) wideband non-stationary end-to-end channel model for RIS assisted multiple-input multiple-output (MIMO) communications, which takes into account the physical properties of RIS, such as unit numbers, unit sizes, array orientations and array configurations. By …

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Prepreg And Core Dielectric Permittivity (Εr) Extraction For Fabricated Striplines' Far-End Crosstalk Modeling, Shaohui Yong, Srinath Penugonda, Donghyun Kim, Victor Khilkevich, Bo Pu, Xiaoning Ye, Qian Gao, Xiao Ding Cai, Bidyut Sen, Jun Fan Feb 2022

Prepreg And Core Dielectric Permittivity (Εr) Extraction For Fabricated Striplines' Far-End Crosstalk Modeling, Shaohui Yong, Srinath Penugonda, Donghyun Kim, Victor Khilkevich, Bo Pu, Xiaoning Ye, Qian Gao, Xiao Ding Cai, Bidyut Sen, Jun Fan

Electrical and Computer Engineering Faculty Research & Creative Works

As the data rate and density of digital high-speed systems are getting higher, far-end crosstalk (FEXT) noise becomes one of the major issues that limit signal integrity performance. It was commonly believed that FEXT would be eliminated for strip lines routed in a homogeneous dielectric, but in reality, FEXT can always be measured in strip lines on the fabricated printed circuit boards. A slightly different dielectric permittivity (ϵr) of prepreg and core may be one of the major contributors to the FEXT. This article is focusing on providing a practical FEXT modeling methodology for strip lines by introducing an approach …

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Comprehensive Evaluation Of A High-Temperature Resistant Re-Crosslinkable Preformed Particle Gel For Water Management, Bowen Yu, Shuda Zhao, Yifu Long, Baojun Bai, Thomas P. Schuman Feb 2022

Comprehensive Evaluation Of A High-Temperature Resistant Re-Crosslinkable Preformed Particle Gel For Water Management, Bowen Yu, Shuda Zhao, Yifu Long, Baojun Bai, Thomas P. Schuman

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Gel treatment has been widely applied to control conformance for improving oil recovery and control water production in mature oil fields. However, most of the hydrogel systems are limited when being applied in the harsh environments of high temperatures. A systematic evaluation was conducted in this study to evaluate a modified PPG product, the high temperature resistant re-crosslinkable preformed particle gel (HT-RPPG) which can re-crosslink to form a bulky material and keep thermostable in the large-opening features after placement. This material was developed to overcome the limitations of conventional PPGs in the reservoirs with large- opening features such as open …

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A Detailed Hydrodynamic Study Of The Split-Plate Airlift Reactor By Using Non-Invasive Gamma-Ray Techniques, Laith S. Sabri, Abbas J. Sultan, Hasan Shakir Majdi, Shadha K. Jebur, Muthanna H. Al-Dahhan Feb 2022

A Detailed Hydrodynamic Study Of The Split-Plate Airlift Reactor By Using Non-Invasive Gamma-Ray Techniques, Laith S. Sabri, Abbas J. Sultan, Hasan Shakir Majdi, Shadha K. Jebur, Muthanna H. Al-Dahhan

Chemical and Biochemical Engineering Faculty Research & Creative Works

This study focused on detailed investigations of selected local hydrodynamics in split airlift reactor by using an unconventional measurements facility: computed tomography (CT) and radioactive particle tracking (RPT). The local distribution in a cross-sectional manner with its radial's profiles for gas holdup, liquid velocity flow field, shear stresses, and turbulent kinetic energy were studied under various gas velocity 1, 2 and 3 cm/s with various six axial level z = 12, 20, 40, 60, 90 and 112 cm. The distribution in gas–liquid phases in the whole split reactor column, the riser and downcomer sides, including their behavior at the top …

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