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2022

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Articles 6841 - 6870 of 9373

Full-Text Articles in Engineering

Glycerol-Driven Denitratation: Process Kinetics, Microbial Ecology, And Operational Controls, Matthew Baideme, Chenghua Long, Luke Plante, Jeffrey A. Starke, Michael A. Butkus, Katrik Chandran Feb 2022

Glycerol-Driven Denitratation: Process Kinetics, Microbial Ecology, And Operational Controls, Matthew Baideme, Chenghua Long, Luke Plante, Jeffrey A. Starke, Michael A. Butkus, Katrik Chandran

Civil and Environmental Engineering Faculty Research and Publications

Denitratation, the selective reduction of nitrate to nitrite, is a novel process and when coupled with anaerobic ammonium oxidation (anammox) could achieve resource-efficient biological nitrogen removal of ammonium- and nitrate-laden waste streams. Using a fundamentally-based, first principles approach, this study optimized a stoichiometrically-limited, glycerol-driven denitratation process and characterized mechanisms supporting nitrite accumulation with results that aligned with expectations. At the optimal influent chemical oxygen demand to nitrate ratio of 3.0 : 1 identified, glycerol supported selective nitrate reduction to nitrite (nitrite accumulation ratio, NAR = 62%) and near-complete nitrate conversion (nitrate reduction ratio, NRR = 96%), indicating its viability in …

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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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Volumetric Lattice Boltzmann Method For Wall Stresses Of Image-Based Pulsatile Flows, Xiaoyu Zhang, Joan Gomez-Paz, Xi Chen, James M. Mcdonough, Md Mahfuzul Islam, Yiannis Andreopoulos, Luoding Zhu, Huidan Yu Feb 2022

Volumetric Lattice Boltzmann Method For Wall Stresses Of Image-Based Pulsatile Flows, Xiaoyu Zhang, Joan Gomez-Paz, Xi Chen, James M. Mcdonough, Md Mahfuzul Islam, Yiannis Andreopoulos, Luoding Zhu, Huidan Yu

Mechanical Engineering Faculty Publications

Image-based computational fluid dynamics (CFD) has become a new capability for determining wall stresses of pulsatile flows. However, a computational platform that directly connects image information to pulsatile wall stresses is lacking. Prevailing methods rely on manual crafting of a hodgepodge of multidisciplinary software packages, which is usually laborious and error-prone. We present a new computational platform, to compute wall stresses in image-based pulsatile flows using the volumetric lattice Boltzmann method (VLBM). The novelty includes: (1) a unique image processing to extract flow domain and local wall normality, (2) a seamless connection between image extraction and VLBM, (3) an en-route …

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Small-Pore Zeolite Membranes: A Review Of Gas Separation Applications And Membrane Preparation, Zishu Cao, Ninad Anjikar, Shaowei Yang Feb 2022

Small-Pore Zeolite Membranes: A Review Of Gas Separation Applications And Membrane Preparation, Zishu Cao, Ninad Anjikar, Shaowei Yang

Chemical & Biomedical Engineering Faculty Publications

There have been significant advancements in small-pore zeolite membranes in recent years. With pore size closely related to many energy- or environment-related gas molecules, small-pore zeolite membranes have demonstrated great potential for the separation of some interested gas pairs, such as CO2/CH4, CO2/N-2 and N-2/CH4. Small-pore zeolite membranes share some characteristics but also have distinctive differences depending on their framework, structure and zeolite chemistry. Through this mini review, the separation performance of different types of zeolite membranes with respect to interested gas pairs will be compared. We aim to give readers an idea of membrane separation status. A few representative …

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Estonian Internet Voting With Anonymous Credentials, İsa Sertkaya, Peter Roenne, Peter Y. A. Ryan Feb 2022

Estonian Internet Voting With Anonymous Credentials, İsa Sertkaya, Peter Roenne, Peter Y. A. Ryan

Turkish Journal of Electrical Engineering and Computer Sciences

The Estonian Internet voting (EIV) scheme is a unique example of a long-term nation-wide, legally binding electronic voting deployment. The EIV scheme is used in parallel with standard paper-based election day voting, of course invalidating an already cast i-vote. This necessarily requires careful authentication of the eligible voters and makes the Estonian identity card solution a crucial part of the scheme, however, note that Parsovs has recently drawn attention to the security flaws found in Estonian ID-cards. In this study, we propose an e-voting scheme EIV-AC that integrates the EIV scheme with anonymous credentials based on self-sovereign identity. In addition …

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Experimental Evaluation Of Liquid Nitrogen Fracturing On The Development Of Tight Gas Carbonate Rocks In The Lower Indus Basin, Pakistan, Muhammad Ali, Abdul Majeed Shar, Aftab Ahmed Mahesar, Ahmed Al-Yaseri, Nurudeen Yekeen, Khalil Rehman Memon, Alireza Keshavarz, Hussein Hoteit Feb 2022

Experimental Evaluation Of Liquid Nitrogen Fracturing On The Development Of Tight Gas Carbonate Rocks In The Lower Indus Basin, Pakistan, Muhammad Ali, Abdul Majeed Shar, Aftab Ahmed Mahesar, Ahmed Al-Yaseri, Nurudeen Yekeen, Khalil Rehman Memon, Alireza Keshavarz, Hussein Hoteit

Research outputs 2022 to 2026

Tight gas carbonate formations have enormous potential to meet the supply and demand of the ever-growing population. However, it is impossible to produce from these formations due to the reduced permeability and lower marginal porosity. Several methods have been used to extract unconventional tight gas from these reservoirs, including hydraulic fracturing and acidizing. However, field studies have demonstrated that these methods have environmental flaws and technical problems. Liquid nitrogen (LN2) fracturing is an effective stimulation technique that provides sudden thermal stress in the rock matrix, creating vivid fractures and improving the petro-physical potential. In this study, we acquired …

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Utilization Of Triply Periodic Minimal Surface (Tpms) Based Architectures Impregnated With Phase Change Material For Heat Transfer Applications, Zahid Ahmed Qureshi Feb 2022

Utilization Of Triply Periodic Minimal Surface (Tpms) Based Architectures Impregnated With Phase Change Material For Heat Transfer Applications, Zahid Ahmed Qureshi

Dissertations

This dissertation is concerned with the utilization of mathematically architected Triply Periodic Minimal Surface (TPMS) based lattices for Latent Heat Thermal Energy Storage (LHTES) systems. With the advent of Additive Manufacturing (AM), TPMS structures can be readily manufactured. The objective of this dissertation was to investigate the heat transfer performance of TPMS structures vis-à-vis conventional metal foams represented by Kelvin cells while both were impregnated with a Phase Change Material (PCM). Numerical simulations were performed under various boundary conditions to assess the performance. It was found that TPMS structures outperformed conventional metal foam. Moreover, the effects of boundary conditions (isothermal …

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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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Low-Cost Solar Collectors To Pre-Heat Ventilation Air In Broiler Houses, Yi Liang, Michael Janorschke, Chad E. Hayes Feb 2022

Low-Cost Solar Collectors To Pre-Heat Ventilation Air In Broiler Houses, Yi Liang, Michael Janorschke, Chad E. Hayes

Biological and Agricultural Engineering Faculty Publications and Presentations

The objective of the study was to evaluate the effect of a low-cost solar collector to pre-heat ventilation air in commercial broiler buildings on supplemental heating demand and air quality during the cold season. Six black fabric-based solar collectors of 36 m(2) each were installed on the south-facing rooftop of a broiler house. The solar collectors provided fresh warm air into the house during the ON cycle of minimum ventilation and during the OFF cycle of minimum ventilation when the temperature under the collectors met certain criteria. The daily cumulative duration of solar collectors in operation averaged 125 and 133 …

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Forming A Decentralized Research Network: Ds4h, Eni̇s Karaarslan, Meli̇h Bi̇ri̇m, Hüseyi̇n Emre Ari Feb 2022

Forming A Decentralized Research Network: Ds4h, Eni̇s Karaarslan, Meli̇h Bi̇ri̇m, Hüseyi̇n Emre Ari

Turkish Journal of Electrical Engineering and Computer Sciences

There is a trend toward decentralized systems, but these systems are developed without conducting enough software tests. Also, the performance, scalability, and sustainability of the decentralized systems are not taken into account. One of the reasons is the time-consuming testing process. The other is the hardware requirements and the complexity of the software installations of the testing environment. Developer communities need stable and secure research networks to test and develop prototypes before releasing the working versions. Cloud-based blockchain test networks are available, but it allows using a specific framework. Also, users are required to learn how to use each framework. …

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Blocksim-Net: A Network-Based Blockchain Simulator, Prashanthi Ramachandran, Nandini Agrawal, Osman Bi̇çer, Alpteki̇n Küpçü Feb 2022

Blocksim-Net: A Network-Based Blockchain Simulator, Prashanthi Ramachandran, Nandini Agrawal, Osman Bi̇çer, Alpteki̇n Küpçü

Turkish Journal of Electrical Engineering and Computer Sciences

Since its proposal by Eyal and Sirer (CACM '13), selfish mining attacks on proof-of-work blockchains have been studied extensively. The main body of this research aims at both studying the extent of its impact and defending against it. Yet, before any practical defense is deployed in a real world blockchain system, it needs to be tested for security and dependability. However, real blockchain systems are too complex to conduct any test on or benchmark the developed protocols. Instead, some simulation environments have been proposed recently, such as BlockSim (Maher et al., SIGMETRICS Perform. Eval. Rev. '19), which is a modular …

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Block Size Optimization For Pow Consensus Algorithm Based Blockchainapplications By Using Whale Optimization Algorithm, Betül Aygün, Hi̇lal Arslan Feb 2022

Block Size Optimization For Pow Consensus Algorithm Based Blockchainapplications By Using Whale Optimization Algorithm, Betül Aygün, Hi̇lal Arslan

Turkish Journal of Electrical Engineering and Computer Sciences

Blockchain-based applications come up with cryptocurrencies, especially Bitcoin, introducing a distributed ledger technologies for peer-to-peer networks and essentially records the transactions in blocks containing hash value of the previous blocks. Block generation constitutes the basis of this technology, and the optimization of such systems is among the most crucial concerns. Determining either the block size or the number of transactions in the block brings out a remarkable problem that has been solved by the miners in recent years. First, higher block size results in higher transaction time, on the other hand, smaller block size has many disadvantages such as security, …

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Tri-Op Redactable Blockchains With Block Modification, Removal, And Insertion, Mohammad Sadeq Dousti, Alpteki̇n Küpçü Feb 2022

Tri-Op Redactable Blockchains With Block Modification, Removal, And Insertion, Mohammad Sadeq Dousti, Alpteki̇n Küpçü

Turkish Journal of Electrical Engineering and Computer Sciences

In distributed computations and cryptography, it is desirable to record events on a public ledger, such that later alterations are computationally infeasible. An implementation of this idea is called blockchain, which is a distributed protocol that allows the creation of an immutable ledger. While such an idea is very appealing, the ledger may be contaminated with incorrect, illegal, or even dangerous data, and everyone running the blockchain protocol has no option but to store and propagate the unwanted data. The ledger is bloated over time, and it is not possible to remove redundant information. Finally, missing data cannot be inserted …

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Performance Analysis Of Lightweight Internet Of Things Devices On Blockchainnetworks, Cem Kösemen, Gökhan Dalkiliç, Şafak Öksüzer Feb 2022

Performance Analysis Of Lightweight Internet Of Things Devices On Blockchainnetworks, Cem Kösemen, Gökhan Dalkiliç, Şafak Öksüzer

Turkish Journal of Electrical Engineering and Computer Sciences

Potential integration or cooperation of the Internet of things (IoT) systems and the blockchain technology is nowadays attracting remarkable interest from the researchers. These inter-operating systems often have to rely on lowcost, low-power, and robust IoT devices that can communicate with the blockchain network through smart contracts. In this work, we designed and ran a benchmark study for ESP32-based lightweight IoT devices interacting within the Quorum blockchain. A software library was built for ESP32 devices to enable elliptic-curve digital signing, Keccak-256 hashing, decoding, encoding, and secure private key generation capabilities, which all are the basic functional requirements for running a …

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A Survey Of Blind Modulation Classification Techniques For Ofdm Signals, Anand Kumar, Sudhan Majhi, Guan Gui, Hsiao-Chun Wu, Chau Yuen Feb 2022

A Survey Of Blind Modulation Classification Techniques For Ofdm Signals, Anand Kumar, Sudhan Majhi, Guan Gui, Hsiao-Chun Wu, Chau Yuen

Faculty Publications

Blind modulation classification (MC) is an integral part of designing an adaptive or intelligent transceiver for future wireless communications. Blind MC has several applications in the adaptive and automated systems of sixth generation (6G) communications to improve spectral efficiency and power efficiency, and reduce latency. It will become a integral part of intelligent software-defined radios (SDR) for future communication. In this paper, we provide various MC techniques for orthogonal frequency division multiplexing (OFDM) signals in a systematic way. We focus on the most widely used statistical and machine learning (ML) models and emphasize their advantages and limitations. The statistical-based blind …

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A Survey Of Blind Modulation Classification Techniques For Ofdm Signals, Anand Kumar, Sudhan Majhi, Guan Gui, Hsiao-Chun Wu, Chau Yuen Feb 2022

A Survey Of Blind Modulation Classification Techniques For Ofdm Signals, Anand Kumar, Sudhan Majhi, Guan Gui, Hsiao-Chun Wu, Chau Yuen

Faculty Publications

Blind modulation classification (MC) is an integral part of designing an adaptive or intelligent transceiver for future wireless communications. Blind MC has several applications in the adaptive and automated systems of sixth generation (6G) communications to improve spectral efficiency and power efficiency, and reduce latency. It will become a integral part of intelligent software-defined radios (SDR) for future communication. In this paper, we provide various MC techniques for orthogonal frequency division multiplexing (OFDM) signals in a systematic way. We focus on the most widely used statistical and machine learning (ML) models and emphasize their advantages and limitations. The statistical-based blind …

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Development Of Guidelines For Collecting Transit Ridership Data, Hong Yang, Kun Xie, Sherif Ishak, Qingyu Ma, Yang Liu Feb 2022

Development Of Guidelines For Collecting Transit Ridership Data, Hong Yang, Kun Xie, Sherif Ishak, Qingyu Ma, Yang Liu

Computational Modeling & Simulation Engineering Faculty Publications

Transit ridership is a critical determinant for many transit applications such as operation optimizations and project prioritization under performance-based funding mechanisms. As a result, the quality of ridership data is of utmost importance to both transit administrative agencies and transit operators. Many transit operators in Virginia report their ridership data to the Department of Rail and Public Transportation (DRPT) and the National Transit Database (NTD). However, with no specific guidelines available to transit agencies in Virginia for collecting ridership data, the heterogeneous mixture of diverse data collection methods and technologies has often raised concerns about the consistency and quality of …

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High-Temperature Analysis Of Optical Coupling Using Algaas/Gaas Leds For High-Density Integrated Power Modules, Syam Madhusoodhanan, Abbas Sabbar, Huong Tran, Pengyu Lai, David Gonzalez, H. Alan Mantooth, Shui-Qing Yu, Zhong Chen Feb 2022

High-Temperature Analysis Of Optical Coupling Using Algaas/Gaas Leds For High-Density Integrated Power Modules, Syam Madhusoodhanan, Abbas Sabbar, Huong Tran, Pengyu Lai, David Gonzalez, H. Alan Mantooth, Shui-Qing Yu, Zhong Chen

Electrical Engineering Faculty Publications and Presentations

A low-temperature co-fired ceramic (LTCC)-based optocoupler design is demonstrated as a possible solution for optical isolation in high-density integrated power modules. The design and fabrication of LTCC based package are discussed. Commercially available aluminum gallium arsenide/gallium arsenide (AlGaAs/GaAs) double heterostructure is used both as emitter and photodetector in the proposed optocoupler. A detailed study on the electroluminescence and spectral response of the AlGaAs/GaAs structure is conducted at elevated temperatures. The material figure of merit parameter, D*, is calculated in the temperature range 77-800 K. The fabricated optocoupler is tested at elevated temperatures, and the results are presented.

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Anesthetics Affect Peripheral Venous Pressure Waveforms And The Cross-Talk With Arterial Pressure, Ali Z. Al-Alawi, Kaylee R. Henry, Lauren D. Crimmins, Patrick C. Bonasso, Md Abul Hayat, Melvin S. Dassinger, Jeffrey M. Burford, Hanna K. Jensen, Joseph Sanford, Jingxian Wu, Kevin W. Sexton, Morten O. Jensen Feb 2022

Anesthetics Affect Peripheral Venous Pressure Waveforms And The Cross-Talk With Arterial Pressure, Ali Z. Al-Alawi, Kaylee R. Henry, Lauren D. Crimmins, Patrick C. Bonasso, Md Abul Hayat, Melvin S. Dassinger, Jeffrey M. Burford, Hanna K. Jensen, Joseph Sanford, Jingxian Wu, Kevin W. Sexton, Morten O. Jensen

Biomedical Engineering Faculty Publications and Presentations

Analysis of peripheral venous pressure (PVP) waveforms is a novel method of monitoring intravascular volume. Two pediatric cohorts were studied to test the effect of anesthetic agents on the PVP waveform and cross-talk between peripheral veins and arteries: (1) dehydration setting in a pyloromyotomy using the infused anesthetic propofol and (2) hemorrhage setting during elective surgery for craniosynostosis with the inhaled anesthetic isoflurane. PVP waveforms were collected from 39 patients that received propofol and 9 that received isoflurane. A multiple analysis of variance test determined if anesthetics influence the PVP waveform. A prediction system was built using k-nearest neighbor (k-NN) …

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Design And Optimization Of High Temperature Optocouplers As Galvanic Isolation, Abbas Sabbar, Syam Madhusoodhanan, Huong Tran, Binzhong Dong, Jiangbo Wang, H. Alan Mantooth, Shui-Qing Yu, Zhong Chen Feb 2022

Design And Optimization Of High Temperature Optocouplers As Galvanic Isolation, Abbas Sabbar, Syam Madhusoodhanan, Huong Tran, Binzhong Dong, Jiangbo Wang, H. Alan Mantooth, Shui-Qing Yu, Zhong Chen

Electrical Engineering Faculty Publications and Presentations

The commercial InGaN-based (blue and green) and AlGaInP-based (red) multiple quantum well (MQW) lighting emitting diodes (LEDs) were studied in a wide range of temperatures up to 800 K for their light emission and detection (i.e., LEDs operated under reverse bias as photodiodes (PDs)) characteristics. The results indicate the feasibility of integrating a pair of selected LEDs to fabricate high temperature (HT) optocouplers, which can be utilized as galvanic isolation to replace the bulky isolation transforms in the high-density power modules. A detailed study on LEDs and PDs were performed. The external quantum efficiency (EQE) of the LED and PDs …

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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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Tracking The Heavy Metal Contaminants Entrained With The Flow Into A Trickle Bed Hydrotreating Reactor Packed With Different Catalyst Shapes Using Newly Developed Noninvasive Dynamic Radioactive Particle Tracking, Binbin Qi, Omar Farid, Alexandre França Velo, Jihane Mendil, Sebastián Uribe, Yasunobu Kaneko, Kei Sakakura, Yasuhito Kagota, Muthanna H. Al-Dahhan Feb 2022

Tracking The Heavy Metal Contaminants Entrained With The Flow Into A Trickle Bed Hydrotreating Reactor Packed With Different Catalyst Shapes Using Newly Developed Noninvasive Dynamic Radioactive Particle Tracking, Binbin Qi, Omar Farid, Alexandre França Velo, Jihane Mendil, Sebastián Uribe, Yasunobu Kaneko, Kei Sakakura, Yasuhito Kagota, Muthanna H. Al-Dahhan

Chemical and Biochemical Engineering Faculty Research & Creative Works

A newly developed modified Dynamic Radioactive Particle Tracking system (DRPT) was used to investigate the heavy metal contaminants deposition locations in different catalyst beds, sphere, cylinder, trilobe, and quadrilobed in Trickle Bed Reactors. In the present paper, Kernel Density Estimator (KDE) was used to estimate the probability density distributions of heavy metal contaminants depositions in terms of bed radius height. The result shows that the four cases have similar probability density distribution in terms of radius, while the spherical catalyst has the larger distribution range in terms of bed height. The heavy metal deposition is directly related to the pressure …

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Characterizing The Effect Of Adding Boron Nitride Nanotubes On The Mechanical Properties Of Electrospun Polymer Nanocomposite Microfibers Mesh, Ohood Alsmairat, Nael Barakat Feb 2022

Characterizing The Effect Of Adding Boron Nitride Nanotubes On The Mechanical Properties Of Electrospun Polymer Nanocomposite Microfibers Mesh, Ohood Alsmairat, Nael Barakat

Mechanical Engineering Faculty Publications and Presentations

Electrospun fibrous meshes have a variety of applications such as filtration, drug delivery, energy storage, and engineered tissues due to their high surface area to mass ratio. Therefore, understanding the mechanical properties of these continuously evolving meshes is critical to expand and improve their performance. In this study, the effect of adding Boron Nitride Nanotube (BNNT) to Polymethylmethacrylate (PMMA) composite meshes on the mechanical properties of the polymer is studied. Electrospinning is used to fabricate microfiber meshes of PMMA and BNNT-PMMA. The fabricated meshes are tested experimentally with a uniaxial tensile tester. In addition, a theoretical model is introduced to …

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Asphaltene Thermodynamic Precipitation During Miscible Nitrogen Gas Injection, Mukhtar Elturki, Abdulmohsin Imqam Feb 2022

Asphaltene Thermodynamic Precipitation During Miscible Nitrogen Gas Injection, Mukhtar Elturki, Abdulmohsin Imqam

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

For many years, miscible gas injection has been the most beneficial enhanced oil recovery method in the oil and gas industry. However, injecting a miscible gas to displace oil often causes the flocculation and deposition of asphaltenes, which subsequently leads to a number of production problems. Nitrogen gas (N2) injection has been used to enhance oil recovery in some oil fields, seeking to improve oil recovery. However, few works have implemented N2 injection and investigated its effect on asphaltene precipitation and deposition. This research investigated the N2 miscible flow mechanism in nanopores and its impact on asphaltene precipitations, which can …

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Proppant Transport Using High-Viscosity Friction Reducer Fracture Fluids At High-Temperature Environment, Ghith Biheri, Abdulmohsin Imqam Feb 2022

Proppant Transport Using High-Viscosity Friction Reducer Fracture Fluids At High-Temperature Environment, Ghith Biheri, Abdulmohsin Imqam

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

The stimulation of unconventional reservoirs to improve oil productivity in tight formations of shale basins is a key objective in hydraulic fracturing treatments. Such stimulation can be made by reliable fracture fluids that have a high viscosity and elasticity to suspend the proppant in the fracture networks. Recently, due to several operational and economic reasons, the oil industry began using highviscosity friction reducers (HVFRs) as direct replacements for linear and crosslinked gels. However, some issues can limit the capability of HVFRs to provide effective sand transport, including the high fluid temperature during fracture treatment inside the formations. This may lead …

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Impact Of Clay Stabilizer On The Methane Desorption Kinetics And Isotherms Of Longmaxi Shale, China, Zhong Hua Liu, Jia Chun Wang, Baojun Bai, Yan Ling Wang Feb 2022

Impact Of Clay Stabilizer On The Methane Desorption Kinetics And Isotherms Of Longmaxi Shale, China, Zhong Hua Liu, Jia Chun Wang, Baojun Bai, Yan Ling Wang

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Knowing methane desorption characteristics is essential to define the contribution of adsorbed gas to gas well production. To evaluate the synthetic effect of a clay stabilizer solution on methane desorption kinetics and isotherms pertaining to Longmaxi shale, an experimental setup was designed based on the volumetric method. The objective was to conduct experiments on methane adsorption and desorption kinetics and isotherms before and after clay stabilizer treatments. The experimental data were a good fit for both the intraparticle diffusion model and the Freundlich isotherm model. We analyzed the effect of the clay stabilizer on desorption kinetics and isotherms. Results show …

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Developing Mix Proportions For Class C Fly Ash-Based Alkali-Activated 3d-Printed Concrete Mixtures, Fareh Abudawaba, Eslam Gomaa, Ahmed Gheni, Mohamed Elgawady Feb 2022

Developing Mix Proportions For Class C Fly Ash-Based Alkali-Activated 3d-Printed Concrete Mixtures, Fareh Abudawaba, Eslam Gomaa, Ahmed Gheni, Mohamed Elgawady

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

This study investigated the use of class C fly ash (FA) as a precursor for alkali-activated mortar (AAM) for 3D-printed concrete (3DPC). AAMs with different water-to-FA (W/FA), alkaline activator-to-FA (Alk/FA), and sodium silicate-to-sodium hydroxide (SS/SH) ratios were examined to develop mixtures that can be tailored for different structural applications of 3DPC. The fresh properties, including extrudability and buildability, were evaluated through the open time (OT) and immediate deformation tests, respectively. Different cycle times (CTs) were applied to achieve a strain limit state necessary to maintain the printed shape. The strength of AAMs in different directions at different CTs was examined. …

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