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2022

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Articles 6811 - 6840 of 9373

Full-Text Articles in Engineering

Synergic Antitumor Effect Of Photodynamic Therapy And Chemotherapy Mediated By Nano Drug Delivery Systems, Mozhgan Aghajanzadeh, Mostafa Zamani, Fereshteh Rajabi Kouchi, Josh Eixenberger, Dorsa Shirini, David Estrada, Farhad Shirini Feb 2022

Synergic Antitumor Effect Of Photodynamic Therapy And Chemotherapy Mediated By Nano Drug Delivery Systems, Mozhgan Aghajanzadeh, Mostafa Zamani, Fereshteh Rajabi Kouchi, Josh Eixenberger, Dorsa Shirini, David Estrada, Farhad Shirini

Materials Science and Engineering Faculty Publications and Presentations

This review provides a summary of recent progress in the development of different nano-platforms for the efficient synergistic effect between photodynamic therapy and chemotherapy. In particular, this review focuses on various methods in which photosensitizers and chemotherapeutic agents are co-delivered to the targeted tumor site. In many cases, the photosensitizers act as drug carriers, but this review, also covers different types of appropriate nanocarriers that aid in the delivery of photosensitizers to the tumor site. These nanocarriers include transition metal, silica and graphene-based materials, liposomes, dendrimers, polymers, metal–organic frameworks, nano emulsions, and biologically derived nanocarriers. Many studies have demonstrated various …

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Using Phreeqc To Model Cement Hydration, Niall Holmes Dr., Mark Tyrer, Roger P. West Prof, Aaron Lowe, Denis Kelliher Feb 2022

Using Phreeqc To Model Cement Hydration, Niall Holmes Dr., Mark Tyrer, Roger P. West Prof, Aaron Lowe, Denis Kelliher

Articles

This paper presents the steps involved in undertaking an analysis of hydrating cements with different levels of limestone powder using the PHREEQC geochemical software with the Notepad++ editor. The analysis begins with determining which solid phases are thermodynamically predicted to precipitate and form using the oxide compositions of commercial CEM I and CEM II/A-L cements. When the phases are known, PHREEQC is programmed to provide predictions of the phase dissolution and phase assemblage over time (here, 1000 days of hydration) as well as the pore solution chemistry. Thermodynamics has been successfully applied to the field of cement hydration to predict …

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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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The David Oberhelman Collection Of Science Fiction, Fantasy, And Tolkieniana At Oklahoma State University, Phillip Fitzsimmons Feb 2022

The David Oberhelman Collection Of Science Fiction, Fantasy, And Tolkieniana At Oklahoma State University, Phillip Fitzsimmons

Faculty Books & Book Chapters

In September 2020 I drove to the Oklahoma State University (OSU) Stillwater campus to see “The David Oberhelman J. R. R. Tolkien Collection” exhibit, on display on the Edmon Low Library’s second-floor mezzanine in the Lisa and Mark Snell Gallery.

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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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Thermoforming Process Effects On Structural Performance Of Carbon Fiber Reinforced Thermoplastic Composite Parts Through A Manufacturing To Response Pathway, Madhura Limaye, Sai Aditya Pradeep, Anmol Kothari, Sushil Savla, Akshat Agha, Srikanth Pilla, Gang Li Feb 2022

Thermoforming Process Effects On Structural Performance Of Carbon Fiber Reinforced Thermoplastic Composite Parts Through A Manufacturing To Response Pathway, Madhura Limaye, Sai Aditya Pradeep, Anmol Kothari, Sushil Savla, Akshat Agha, Srikanth Pilla, Gang Li

Publications

Thermoforming process of thermoplastic-based continuous CFRP's offer a major advantage in reducing cycle times for large-scale productions, but it can also have a significant impact on the structural performance of the parts by inducing undesirable effects. This necessitates the development of an optimal manufacturing process that minimizes the introduction of undesirable factors in the structure and thereby achieves the targeted mechanical performance. This can be done by first establishing a relationship between the manufacturing process and mechanical performance and successively optimizing it to achieve the desired targets. The current study focuses on the former part, where a manufacturing-to-response (MTR) pathway …

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A New Approach For Grasp Quality Calculation Using Continuous Boundary Formulation Of Grasp Wrench Space, Shuwei Qiu, Mehrdad Kermani Ph.D., P.Eng. Feb 2022

A New Approach For Grasp Quality Calculation Using Continuous Boundary Formulation Of Grasp Wrench Space, Shuwei Qiu, Mehrdad Kermani Ph.D., P.Eng.

Electrical and Computer Engineering Publications

In this paper, we aim to use a continuous formulation to efficiently calculate the well-known wrench-based grasp metric proposed by Ferrari and Canny which is the minimum distance from the wrench space origin to the boundary of the grasp wrench space. Considering the L∞" role="presentation" style="box-sizing: border-box; margin: 0px; padding: 0px; display: inline-block; line-height: normal; font-size: 16.200000762939453px; word-spacing: normal; word-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; position: relative;"> metric and the nonlinear friction cone model, the challenge of calculating this metric is to determine the boundary of the grasp …

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Mass Advection–Diffusion In Creeping Flow Through An Orifice Plate: A Model For Nanoporous Atomically Thin Membranes, Harpreet Atwal, Anika Wong, Michael Boutilier Feb 2022

Mass Advection–Diffusion In Creeping Flow Through An Orifice Plate: A Model For Nanoporous Atomically Thin Membranes, Harpreet Atwal, Anika Wong, Michael Boutilier

Chemical and Biochemical Engineering Publications

Continuum transport equations are commonly applied to nanopores in atomically thin membranes for simple modeling. Although these equations do not apply for nanopores approaching the fluid or solute molecule size, they can be reasonably accurate for larger nanopores. Relatively large graphene nanopores have applications in small particle filtration and appear as unwanted defects in large-area membranes. Solute transport rates through these nanopores determine the rejection performance of the membrane. Atomically thin membranes commonly operate in a regime where advection and diffusion both contribute appreciably to transport. Solute mass transfer rates through larger nanopores have previously been modeled by adding continuum …

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Application Of Nonlinear Time Series And Machine Learning Algorithms For Forecasting Groundwater Flooding In A Lowland Karst Area, Bidroha Basu, Patrick Morrissey, Laurence Gill Feb 2022

Application Of Nonlinear Time Series And Machine Learning Algorithms For Forecasting Groundwater Flooding In A Lowland Karst Area, Bidroha Basu, Patrick Morrissey, Laurence Gill

Publications

In karst limestone areas interactions between ground and surface waters can be frequent, particularly in low lying areas, linked to the unique hydrogeological dynamics of that bedrock aquifer. In extreme hydrological conditions, however, this can lead to wide-spread, long-duration flooding, resulting in significant cost and disruption. This study develops and compares a nonlinear time-series analysis based nonlinear autoregressive model with exogenous variables (NARX), machine learning based near support vector regression as well as a linear time-series ARX model in terms of their performance to predict groundwater flooding in a lowland karst area of Ireland. The models have been developed upon …

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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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A Deep Unsupervised Feature Learning Spiking Neural Network With Binarized Classification Layers For The Emnist Classification, Ruthvik Vaila, John Chiasson, Vishal Saxena Feb 2022

A Deep Unsupervised Feature Learning Spiking Neural Network With Binarized Classification Layers For The Emnist Classification, Ruthvik Vaila, John Chiasson, Vishal Saxena

Electrical and Computer Engineering Faculty Publications and Presentations

End user AI is trained on large server farms with data collected from the users. With ever increasing demand for IoT devices, there is a need for deep learning approaches that can be implemented at the Edge in an energy efficient manner. In this work we approach this using spiking neural networks. The unsupervised learning technique of spike timing dependent plasticity (STDP) and binary activations are used to extract features from spiking input data. Gradient descent (backpropagation) is used only on the output layer to perform training for classification. The accuracies obtained for the balanced EMNIST data set compare favorably …

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Facile One-Step Hydrothermal Method For Nico2s4/Rgo Nanocomposite Synthesis For Efficient Hybrid Supercapacitor Electrodes, Ahmed Mysara, Sayed Y. Attia, Fouad I. El-Hosiny, M A. Sadek, Saad G. Mohamed, M M. Rashad Feb 2022

Facile One-Step Hydrothermal Method For Nico2s4/Rgo Nanocomposite Synthesis For Efficient Hybrid Supercapacitor Electrodes, Ahmed Mysara, Sayed Y. Attia, Fouad I. El-Hosiny, M A. Sadek, Saad G. Mohamed, M M. Rashad

Nanotechnology Research Centre

Spinel nickel-cobalt sulfide (NiCo2S4) supported on reduced graphene oxide (rGO) was fabricated through a facile one-step hydrothermal method for energy storage applications. The distribution of the NiCo2S4 nanoparticles on the rGO surface was found to improve the supercapacitive performance of the assembled device. The NiCo2S4/rGO nanocomposite exhibits outstanding electrochemical behavior with a capacity (C)/specific capacitance (Cs) of 536 C g−1/1072 F g−1 at a current density of 1 A g−1. To further investigate the electrochemical behavior of the NiCo2S4/rGO nanocomposite, a hybrid supercapacitor (HSC) was constructed utilizing a NiCo2S4/rGO positive electrode and an activated carbon …

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Evaluation Of Gev Over Lp3 When Predicting Return Period Annual Exceedance For Santa Ana, San Gabriel And Urbanized Regions In California, Maria Beatriz De Paula Macedo Feb 2022

Evaluation Of Gev Over Lp3 When Predicting Return Period Annual Exceedance For Santa Ana, San Gabriel And Urbanized Regions In California, Maria Beatriz De Paula Macedo

LMU Theses and Dissertations

The objective of this present thesis was to determine whether GEV (Generalized Extreme Value) itself can be a more conservative distribution than LP3 (Log Pearson III) associated with other methods, such as the B17B weighting procedure with Single Grubbs-Beck (SGB) for low outliers, when determining the projected floods in a flood frequency analysis (FFA) for Santa Ana and San Gabriel regions and other urbanized stream gages present in California. In this work, USGS PeakFQ was utilized. From the results obtained, it was possible to state that GEV fitting results were directly affected by the length of the data. When the …

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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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Synthesis And Evaluation Of A Novel Polyacrylamide Functionalized Nano-Silica As A Calcium Carbonate Inhibitor In Upstream Applications, Nadhem Ismail, Ali Alshami, Ibnelwaleed A. Hussein Feb 2022

Synthesis And Evaluation Of A Novel Polyacrylamide Functionalized Nano-Silica As A Calcium Carbonate Inhibitor In Upstream Applications, Nadhem Ismail, Ali Alshami, Ibnelwaleed A. Hussein

Chemical Engineering Faculty Publications

Calcium carbonate scale forms in production and injection wells, precipitating upon pressure and temperature changes, incompatible water mixing, and dehydration. Production shutdown is one of the most dramatic consequences caused by calcium carbonate scale formation. We synthesized, characterized, and tested a polyacrylamide functionalized nano-silica (PAM-SiO2NPs) inhibitor that prevents calcium carbonate formation at high temperatures and high brine. Positive compatibility results were confirmed before the inhibition efficiency test, whereby the efficiency was calculated by quantifying the calcium ions left in solution using ICP-OES. The inhibitor was effective at temperatures of 40, 60, and 80 °C, with pH values of …

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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 Self-Referencing Non-Destructive Test Method To Detect Damage In Reinforced Concrete Bridge Decks Using Nonlinear Vibration Response Characteristics, Ali Hafiz, Thomas Schumacher, Anis M. Raad Feb 2022

A Self-Referencing Non-Destructive Test Method To Detect Damage In Reinforced Concrete Bridge Decks Using Nonlinear Vibration Response Characteristics, Ali Hafiz, Thomas Schumacher, Anis M. Raad

Civil and Environmental Engineering Faculty Publications and Presentations

Several non-destructive test (NDT) methods, namely visual inspection, hammer sounding, chain drag, impulse response testing, impact echo testing, ultrasonic (array) echo testing, and under certain conditions ground penetrating radar (GPR) are currently used to detect and estimate the extent of damage such as delaminations in reinforced concrete bridge decks. In this article, we present a self-referencing NDT method that builds on impulse response (IR) testing to detect damage using nonlinear vibration characteristics. The hypothesis is that for an undamaged deck, varying the impact force applied to a specific test point does not affect the corresponding frequency response function (FRF) for …

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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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Flow And Heat Transfer Characteristics In A Pre-Swirl Rotor-Stator Cavity, Xiaoyu Yang, Zhong Ren, Jing Ren, Philip M. Ligrani Feb 2022

Flow And Heat Transfer Characteristics In A Pre-Swirl Rotor-Stator Cavity, Xiaoyu Yang, Zhong Ren, Jing Ren, Philip M. Ligrani

PRC-Affiliated Research

The present study investigates flow and heat transfer characteristics in a rotor-stator pre-swirl system. Considered are rotational Reynolds numbers ReФ ranging from 3.4 × 105 to 6.8 × 105, with jet Reynolds numbers Rew of approximately 8.8 × 104 to 3.81 × 105, and associated turbulent flow parameter λT = Cw/ReФ0.8 varying from 0 to 0.4. Experimentally-measured and numerically-predicted results illustrate the combined and separate influences of jet impingement and rotor entrainment, as they affect and govern flow and heat transfer characteristics within the cavity. These results show that the relative strength of the two effects varies with ReФ and …

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Flow Structure And Surface Heat Transfer From Numerical Predictions For A Double Wall Effusion Plate With Impingement Jet Array Cooling, Hwabhin Kwon, Phillip M. Ligrani, Sneha Reddy Vanga, Heesung Park Feb 2022

Flow Structure And Surface Heat Transfer From Numerical Predictions For A Double Wall Effusion Plate With Impingement Jet Array Cooling, Hwabhin Kwon, Phillip M. Ligrani, Sneha Reddy Vanga, Heesung Park

PRC-Affiliated Research

To provide additional understanding of double wall cooling arrangements, especially local distributions of flow properties which are responsible for hot-side surface and cold-side surface heat transfer variations, investigated are numerically-simulated distributions of turbulent flow structural characteristics. Also considered are numerically-simulated surface heat transfer characteristics, including comparisons with experimentally-measured distributions. The numerical results are obtained using the ANSYS FLUENT Version 19.1 numerical code, with a k-ω SST turbulence model. The present arrangement includes a full-coverage effusion cooling plate, with coolant initially supplied by an impingement jet array. Considered are the effects of effusion blowing ratio, impingement jet Reynolds number, and streamwise …

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