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Full-Text Articles in Engineering

Cobol Cripples The Mind!: Academia And The Alienation Of Data Processing, Neel Shah Jul 2022

Cobol Cripples The Mind!: Academia And The Alienation Of Data Processing, Neel Shah

Swarthmore Undergraduate History Journal

This paper writes a social history of the programming language COBOL that focuses on its reception in academia. Through this focus, the paper seeks to understand the contentious relationship between data processing and the academy. In historicizing COBOL, the paper also illuminates the changing nature of the academy-industry-military triangle that was a mainstay of early computing.


A Monte Carlo Framework For Incremental Improvement Of Simulation Fidelity, Damian M. Lyons, James Finocchiaro, Misha Novitzky, Chris Korpela Jul 2022

A Monte Carlo Framework For Incremental Improvement Of Simulation Fidelity, Damian M. Lyons, James Finocchiaro, Misha Novitzky, Chris Korpela

Faculty Publications

Robot software developed in simulation often does not be- have as expected when deployed because the simulation does not sufficiently represent reality - this is sometimes called the `reality gap' problem. We propose a novel algorithm to address the reality gap by injecting real-world experience into the simulation. It is assumed that the robot program (control policy) is developed using simulation, but subsequently deployed on a real system, and that the program includes a performance objective monitor procedure with scalar output. The proposed approach collects simulation and real world observations and builds conditional probability functions. These are used to generate …


A Monte Carlo Framework For Incremental Improvement Of Simulation Fidelity, Damian Lyons, James Finocchiaro, Misha Novitsky, Chris Korpela Jul 2022

A Monte Carlo Framework For Incremental Improvement Of Simulation Fidelity, Damian Lyons, James Finocchiaro, Misha Novitsky, Chris Korpela

Faculty Publications

Robot software developed in simulation often does not be- have as expected when deployed because the simulation does not sufficiently represent reality - this is sometimes called the `reality gap' problem. We propose a novel algorithm to address the reality gap by injecting real-world experience into the simulation. It is assumed that the robot program (control policy) is developed using simulation, but subsequently deployed on a real system, and that the program includes a performance objective monitor procedure with scalar output. The proposed approach collects simulation and real world observations and builds conditional probability functions. These are used to generate …


A Half- Yearly E-Newsletter Of The Department Of Computer Science And Engineering, Manipal Institute Of Technology - Jul 2022, Ashalatha Nayak Dr. Jul 2022

A Half- Yearly E-Newsletter Of The Department Of Computer Science And Engineering, Manipal Institute Of Technology - Jul 2022, Ashalatha Nayak Dr.

Faculty work

No abstract provided.


Incorporation Of Torsion Springs In A Knee Exoskeleton For Stance Phase Correction Of Crouch Gait, Katy Baker Bumbard, Harold Herrington, Chung-Hyun Goh, Alwathiqbellah Ibrahim Jul 2022

Incorporation Of Torsion Springs In A Knee Exoskeleton For Stance Phase Correction Of Crouch Gait, Katy Baker Bumbard, Harold Herrington, Chung-Hyun Goh, Alwathiqbellah Ibrahim

Mechanical Engineering Faculty Publications and Presentations

Crouch gait is a motor complication that is commonly associated with cerebral palsy, spastic diplegia, stroke, and motor-neurological pathologies, broadly defined as knee flexion in excess of 20° in the gait cycle. Uncorrected crouch gait results in fatigue, joint degradation, and loss of ambulation. Torsion springs have been used in cycling to store energy in the knee flexion to reduce fatigue in the quadriceps during knee extension. SolidWorks was used to design a passive exoskeleton for the knee, incorporating torsion springs of stiffnesses 20,000 N/mm and 30,000 N/mm at the knee joint, to correct four different crouch gaits. OpenSim was …


Santa Clara Magazine, Volume 63 Number 1, Summer 2022, Santa Clara University Jul 2022

Santa Clara Magazine, Volume 63 Number 1, Summer 2022, Santa Clara University

Santa Clara Magazine

16 - SHARED DREAMS Meet incoming University President Julie Sullivan, the first layperson and woman selected to lead SCU. Leslie Griffy

20 - BD KNOWS BEST Discovering who you really are, being grateful, and dinosaurs with BD Wong. Lauren Loftus.

22 - SWEPT AWAY Being homeless in Silicon Valley is particularly deadly. One professor explores why so many die in a land of such excess. Leslie Griffy .

28 - ON THE OUTSIDE A first-person account of being wrongly convicted, as told by Arturo Jimenez.

30 - BOOKED AND BUSY The secret behind the Hollywood success of so many Bronco …


A Deep Learning Image Segmentation Model For Agricultural Irrigation System Classification, Ehsan Raei, Ata Akbari Asanjan, Mohammad Reza Nikoo, Mojtaba Sadegh, Shokoufeh Pourshahabi, Jan Franklin Adamowski Jul 2022

A Deep Learning Image Segmentation Model For Agricultural Irrigation System Classification, Ehsan Raei, Ata Akbari Asanjan, Mohammad Reza Nikoo, Mojtaba Sadegh, Shokoufeh Pourshahabi, Jan Franklin Adamowski

Civil Engineering Faculty Publications and Presentations

Effective water management requires a large-scale understanding of agricultural irrigation systems and how they shift in response to various stressors. Here, we leveraged advances in Machine Learning and availability of very high resolution remote sensing imagery to help resolve this long-standing issue. To this end, we developed a deep learning model to classify irrigation systems at a regional scale using remote sensing imagery. After testing different model architectures, hyper parameters, class weights and image sizes, we selected a U-Net architecture with a Resnet-34 backbone for this purpose. We applied transfer learning to increase training efficiency and model performance. We considered …


Spiking Neural Networks And Their Applications: A Review, Kashu Yamazaki, Viet-Khao Vo-Ho, Darshan Bulsara, Ngan Le Jul 2022

Spiking Neural Networks And Their Applications: A Review, Kashu Yamazaki, Viet-Khao Vo-Ho, Darshan Bulsara, Ngan Le

Computer Science and Computer Engineering Faculty Publications and Presentations

The past decade has witnessed the great success of deep neural networks in various domains. However, deep neural networks are very resource-intensive in terms of energy consumption, data requirements, and high computational costs. With the recent increasing need for the autonomy of machines in the real world, e.g., self-driving vehicles, drones, and collaborative robots, exploitation of deep neural networks in those applications has been actively investigated. In those applications, energy and computational efficiencies are especially important because of the need for real-time responses and the limited energy supply. A promising solution to these previously infeasible applications has recently been given …


Life Cycle Cost Analysis Of High Friction Surface Treatment Applications, Eslam Deef-Allah, Korrenn Broaddus, Magdy Abdelrahman Jul 2022

Life Cycle Cost Analysis Of High Friction Surface Treatment Applications, Eslam Deef-Allah, Korrenn Broaddus, Magdy Abdelrahman

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Life cycle cost analyses for high friction surface treatment (HFST) applications were executed relying on a Microsoft Excel program developed by the researchers. Calcined bauxite (CB), five CB alternatives, and epoxy binder were utilized in the HFST applications. The aggregates' performances were evaluated through the aggregate image measurement system (AIMS) before and after Micro-Deval polishing. The performance of the HFST applications was evaluated by the dynamic friction tester (DFT) and British pendulum (BP). The major purpose of this program was to present a rational method for converting different input data (project and material specifics) to comparable output data (net present …


Topological Supercavity Resonances In The Finite System, Lujun Huang, Bin Jia, Yan Kei Chiang, Sibo Huang, Chen Shen, Fu Deng, Tianzhi Yang, David A Powell, Yong Li, Andrey E Miroshnichenko Jul 2022

Topological Supercavity Resonances In The Finite System, Lujun Huang, Bin Jia, Yan Kei Chiang, Sibo Huang, Chen Shen, Fu Deng, Tianzhi Yang, David A Powell, Yong Li, Andrey E Miroshnichenko

Henry M. Rowan College of Engineering Departmental Research

Acoustic resonant cavities play a vital role in modern acoustical systems. The ultrahigh quality-factor resonances are highly desired for some applications such as high-resolution acoustic sensors and acoustic lasers. Here, a class of supercavity resonances is theoretically proposed and experimentally demonstrated in a coupled acoustic resonator system, arising from the merged bound states in the continuum (BICs) in geometry space. Their topological origin is demonstrated by explicitly calculating their topological charges before and after BIC merging, accompanied by charges annihilation. Compared with other types of BICs, they are robust to the perturbation brought by fabrication imperfection. Moreover, it is found …


Large Scale Energy Signature Analysis: Tools For Utility Managers And Planners, Sukjoon Oh, John F. Gardner Jul 2022

Large Scale Energy Signature Analysis: Tools For Utility Managers And Planners, Sukjoon Oh, John F. Gardner

Mechanical and Biomedical Engineering Faculty Publications and Presentations

Building energy signature analysis is a well-established tool for understanding the temperature sensitivity of building energy consumption and measuring energy savings. This tool has been used to measure energy savings of residential, commercial, and even industrial buildings. The public availability of electricity loads (i.e., hourly electricity demand (MW)) from entire Balancing Authorities (BAs) provide an interesting opportunity to apply this approach to a large aggregate load. In this paper, we explore that opportunity for BAs and show that the correlations for large geographical areas are surprisingly coherent when the change-point linear regression analysis is used with the daily interval data …


Quantification Of The State Of Practice Of Offsite Construction And Related Technologies: Current Trends And Future Prospects, Rayan H. Assaad, Islam H. El-Adaway, Makarand Hastak, Kim Lascola Needy Jul 2022

Quantification Of The State Of Practice Of Offsite Construction And Related Technologies: Current Trends And Future Prospects, Rayan H. Assaad, Islam H. El-Adaway, Makarand Hastak, Kim Lascola Needy

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Although some researchers and practitioners have perceived that the current reliance on offsite construction methods is high, other studies have hypothesized that the use of offsite construction techniques is still considered to be somehow limited. To this end, this paper aims to quantify the state of practice of offsite construction in terms of current trends and future prospects for the overall industry as well as the following main sectors: industrial, building and commercial, and infrastructure. First, a questionnaire was formed, pilot-tested, distributed, and completed by 100 construction practitioners. Second, the questionnaire's internal and external validity and reliability were examined using …


The Impact Of Offsite Construction On The Workforce: Required Skillset And Prioritization Of Training Needs, Rayan H. Assaad, Islam H. El-Adaway, Makarand Hastak, Kim Lascola Needy Jul 2022

The Impact Of Offsite Construction On The Workforce: Required Skillset And Prioritization Of Training Needs, Rayan H. Assaad, Islam H. El-Adaway, Makarand Hastak, Kim Lascola Needy

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Offsite construction has showed great potential in addressing many of the industry's problems. While multiple research efforts have been directed at examining different offsite construction aspects, few studies investigated the workforce-related aspects. Therefore, this study aims to address this knowledge gap by examining the impact of offsite construction on the workforce, as represented by the following five workforce categories: offsite, onsite, engineering and design, construction and fabrication, and administrative workforce. To this end, this paper (1) determined the impact of offsite construction on the skillset (reskilling or upskilling) and the demand (shrink or growth) for the offsite and onsite construction …


Electrical Equipment Industry Cluster, Pragati Gautam Jul 2022

Electrical Equipment Industry Cluster, Pragati Gautam

2022 REYES Proceedings

The growing collaboration between two or more industries in a specific region in which they work in a symbiotic relationship, providing benefits to each other and contributing in the overall development of the region, is what is popularly known as business clusters. Even though this concept is commonly known and implemented in the West, South Asian economies are unfamiliar with the advantages of this unique business strategy. There are, undeniably, many potential business clusters in these developing countries, which if tapped efficiently, could result into an industrial boom.

This research focuses on investigating the existence of a business cluster in …


Construction Industry Cluster: An Investigation Of Its Existence In Pakistan, Muhammad Yanzar Sarim Jul 2022

Construction Industry Cluster: An Investigation Of Its Existence In Pakistan, Muhammad Yanzar Sarim

2022 REYES Proceedings

Introduction: Clusters can be defined as a geographical concentration of industries and institutes that are unified and interconnected. These industries and institutes are not just physically close to each other but also gain some advantage from being near to each other.


Supporting Information For “Predictions Of Household Water Affordability Under Conditions Of Climate Change, Demographic Growth, And Fresh Groundwater Depletion In A Southwest Us City Indicate Increasing Burdens On The Poor”, Josiah Heyman, Alex Mayer, Jessica Alger Jul 2022

Supporting Information For “Predictions Of Household Water Affordability Under Conditions Of Climate Change, Demographic Growth, And Fresh Groundwater Depletion In A Southwest Us City Indicate Increasing Burdens On The Poor”, Josiah Heyman, Alex Mayer, Jessica Alger

Departmental Papers (CE)

The Supporting Information contains (a) supplemental tables of annual volumes and costs for each water supply source and by year for each scenario (see Supplemental Information.pdf), (b) the census tract numbers used in the analysis of incomes spent on water (see Supplemental Information.pdf), (c) a correlation matrix for demographic variables and the fraction of households in a census tracts paying > 5% for water in 2070 for the worst case scenario (see Supplemental Information.pdf), and (d) the shapefiles for the El Paso Water utility service area boundaries (see compressed folder boundary11.24.21.gdb).


Perceptions Of Future Careers For Middle Year Engineering Students, Catherine Mcgough Spence, Adam Kirn, Lisa Benson Jul 2022

Perceptions Of Future Careers For Middle Year Engineering Students, Catherine Mcgough Spence, Adam Kirn, Lisa Benson

Integrated Engineering Department Publications

Background: One facet of motivation relevant to students' learning is their perceptions of the future, including future career goals and how those perceptions influence their present actions; this is collectively referred to as their future time perspective (FTP).

Purpose/Hypothesis: This study describes the different FTPs of engineering students. We aim to help researchers and practitioners leverage students' motivations to improve learning experiences and inform future studies by providing a model of engineering students' FTP.

Design/Method: A phenomenographic approach was used to determine students' different characteristic FTPs within the context of their engineering courses. Interviews with engineering students (n=18) at a …


Asymmetric Control Of Light At The Nanoscale, Christos Argyropoulos Jul 2022

Asymmetric Control Of Light At The Nanoscale, Christos Argyropoulos

Department of Electrical and Computer Engineering: Faculty Publications

Breaking reciprocity at the nanoscale can produce directional formation of images due to the asymmetric nonlinear optical response of subwavelength anisotropic resonators. The self-induced passive non-reciprocity has advantages compared to magnet or time modulation approaches and may impact both classical and quantum photonics.


Electrospray Deposition Of Polyvinylidene Fluoride (Pvdf) Microparticles: Impact Of Solvents And Flow Rate, Akinwunmi Joaquim, Omari Paul, Michael Ibezim, Dewayne Johnson, April Falconer, Ying Wu, Frances Williams, Richard Mu Jul 2022

Electrospray Deposition Of Polyvinylidene Fluoride (Pvdf) Microparticles: Impact Of Solvents And Flow Rate, Akinwunmi Joaquim, Omari Paul, Michael Ibezim, Dewayne Johnson, April Falconer, Ying Wu, Frances Williams, Richard Mu

TIGER Institute Faculty Research

Polymeric microparticles have been shown to have great impacts in the area of drug delivery, biosensing, and tissue engineering. Electrospray technology, which provides a simple yet effective technique in the creation of microparticles, was utilized in this work. In addition, altering the electrospray experimental parameters such as applied voltage, flow rate, collector distance, solvents, and the polymer-solvent mixtures can result in differences in the size and morphology of the produced microparticles. The effects of the flow rate at (0.15, 0.3, 0.45, 0.6, 0.8, and 1 mL/h) and N, N-Dimethylformamide (DMF)/acetone solvent ratios (20:80, 40:60, 60:40, 80:20, 100:0 v/v) in the …


Metastable Olivine Within Oceanic Lithosphere In The Uppermost Lower Mantle Beneath The Eastern United States, Fansheng Kong, Stephen S. Gao, Kelly H. Liu, Yinxia Fang, Hejun Zhu, Robert J. Stern, Jiabiao Li Jul 2022

Metastable Olivine Within Oceanic Lithosphere In The Uppermost Lower Mantle Beneath The Eastern United States, Fansheng Kong, Stephen S. Gao, Kelly H. Liu, Yinxia Fang, Hejun Zhu, Robert J. Stern, Jiabiao Li

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Approximately two-thirds of Earth's outermost shell is composed of oceanic plates that form at spreading ridges and recycle back to Earth's interior in subduction zones. A series of physical and chemical changes occur in the subducting lithospheric slab as the temperature and pressure increase with depth. In particular, olivine, the most abundant mineral in the upper mantle, progressively transforms to its high-pressure polymorphs near the mantle transition zone, which is bounded by the 410 km and 660 km discontinuities. However, whether olivine still exists in the core of slabs once they penetrate the 660 km discontinuity remains debated. Based on …


Effects Of Pulsatile Flow Rate And Shunt Ratio In Bifurcated Distal Arteries On Hemodynamic Characteristics Involved In Two Patient-Specific Internal Carotid Artery Sidewall Aneurysms: A Numerical Study, Hang Yi, Mark Johnson, Luke C. Bramlage, Bryan Ludwig, Zifeng Yang Jul 2022

Effects Of Pulsatile Flow Rate And Shunt Ratio In Bifurcated Distal Arteries On Hemodynamic Characteristics Involved In Two Patient-Specific Internal Carotid Artery Sidewall Aneurysms: A Numerical Study, Hang Yi, Mark Johnson, Luke C. Bramlage, Bryan Ludwig, Zifeng Yang

Mechanical and Materials Engineering Faculty Publications

The pulsatile flow rate (PFR) in the cerebral artery system and shunt ratios in bifurcated arteries are two patient-specific parameters that may affect the hemodynamic characteristics in the pathobiology of cerebral aneurysms, which needs to be identified comprehensively. Accordingly, a systematic study was employed to study the effects of pulsatile flow rate (i.e., PFR−I, PFR−II, and PFR−III) and shunt ratio (i.e., 75:25 and 64:36) in bifurcated distal arteries, and transient cardiac pulsatile waveform on hemodynamic patterns in two internal carotid artery sidewall aneurysm models using computational fluid dynamics (CFD) modeling. Numerical results indicate that larger PFRs can cause higher wall …


Dlr Covid-19 Mobility Review - Coastal Mobility Route (Ph1b): Mobility Update, Sarah Rock Dr, Dave O'Connor, Michael Banim Jul 2022

Dlr Covid-19 Mobility Review - Coastal Mobility Route (Ph1b): Mobility Update, Sarah Rock Dr, Dave O'Connor, Michael Banim

Reports

The Phase 1b study is a follow up to the evaluation and review of the Phase 1 'Covid-19 Mobility and Public Realm Works' undertaken by Dun Laoghaire- Rathdown County Council in 2020, which included the development of the Coastal Mobility Route (new cycle infrastructure). These works were part of the Council's response to some of the urban and transport planning challenges associated with Covid-19.

This study reports on ongoing monitoring and evaluation of the changing mobility patterns in the region of the Coastal Mobility Route throughout 2021 and 2022, as government and societal responses to the Covid-19 pandemic changed and …


Robust Sensor Design For The Novel Reduced Models Of The Mead-Marcus Sandwich Beam Equation, Ahmet Aydin Jul 2022

Robust Sensor Design For The Novel Reduced Models Of The Mead-Marcus Sandwich Beam Equation, Ahmet Aydin

Masters Theses & Specialist Projects

Novel space-discretized Finite Differences-based model reductions are proposed for the partial differential equations (PDE) model of a multi-layer Mead-Marcus-type beam with (i) hinged-hinged and (ii) clamped-free boundary conditions. The PDE model describes transverse vibrations for a sandwich beam whose alternating outer elastic layers constrain viscoelastic core layers, which allow transverse shear. The major goal of this project is to design a single boundary sensor, placed at the tip of the beam, to control the overall dynamics on the beam.

For (i), it is first shown that the PDE model is exactly observable by the so-called nonharmonic Fourier series approach. However, …


Deep Learning And Feature Engineering For Human Activity Recognition: Exploiting Novel Rich Learning Representations And Sub-Transfer Learning To Boost Practical Performance, Ria Kanjilal Jul 2022

Deep Learning And Feature Engineering For Human Activity Recognition: Exploiting Novel Rich Learning Representations And Sub-Transfer Learning To Boost Practical Performance, Ria Kanjilal

USF Tampa Graduate Theses and Dissertations

A significant gap exists in our knowledge of how domain-specific feature extraction compares to unsupervised feature learning in the latent space of a deep neural network for a range of temporal applications including human activity recognition. This dissertation aims to address this gap specifically for human activity recognition using acceleration data. To ensure reproducibility, we use two publicly available datasets, UniMiB-SHAR and ExtraSensory, with a well-established history in the human activity recognition literature. We methodically analyze the performance of 64 different combinations of i) learning representations (in the form of raw temporal data or extracted features), ii) traditional and modern …


A Proactive Risk Assessment Framework To Maximize Schedule Benefits Of Modularization In Construction Projects, Mohamad Abdul Nabi, Islam H. El-Adaway Jul 2022

A Proactive Risk Assessment Framework To Maximize Schedule Benefits Of Modularization In Construction Projects, Mohamad Abdul Nabi, Islam H. El-Adaway

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Various studies developed models and decision support tools to assess the feasibility and optimize the use of modularization. However, none has explored the schedule benefits of modular construction. This paper fills this knowledge gap. To this end, the authors completed the following: (1) analyzed the criticalities of the various modular risk factors on potential schedule savings using data collected from 48 industry professionals, (2) investigated the schedule savings associated with the use of modularization using data collected from 68 modular construction projects, and (3) developed an interrelated assessment model to calculate the schedule savings of using modularization. The provided model …


Effect Of Organic Acids On Co2-Rock And Water-Rock Interfacial Tension: Implications For Co2 Geo-Storage, Ahmed Al-Yaseri, Nurudeen Yekeen, Muhammad Ali, Nilanjan Pal, Amit Verma, Hesham Abdulelah, Hussein Hoteit, Mohammad Sarmadivaleh Jul 2022

Effect Of Organic Acids On Co2-Rock And Water-Rock Interfacial Tension: Implications For Co2 Geo-Storage, Ahmed Al-Yaseri, Nurudeen Yekeen, Muhammad Ali, Nilanjan Pal, Amit Verma, Hesham Abdulelah, Hussein Hoteit, Mohammad Sarmadivaleh

Research outputs 2022 to 2026

A small concentration of organic acid in carbon dioxide (CO2) storage formations and caprocks could significantly alter the wettability of such formations into less water-wet conditions, decreasing the CO2-storage potential and containment security. Recent studies have attempted to infer the influence of the organic acid concentration on the wettability of rock–CO2–brine systems by measuring advancing and receding contact angles. However, no studies have investigated the influence of organic acid contamination on CO2-storage capacities from rock-fluid interfacial tension (IFT) data because solid-brine and solid-CO2 IFT values cannot be experimentally measured. Equilibrium contact angles and rock-fluid IFT datasets were used to evaluate …


High Hybrid Power Converter Performance Using Modern‐Optimization‐Methods‐Based Pwm Strategy, Khaled Nusair, Feras Alasali, William Holderbaum, Arangarajan Vinayagam, Asma Aziz Jul 2022

High Hybrid Power Converter Performance Using Modern‐Optimization‐Methods‐Based Pwm Strategy, Khaled Nusair, Feras Alasali, William Holderbaum, Arangarajan Vinayagam, Asma Aziz

Research outputs 2022 to 2026

Recently, interest in DC networks and converters has increased due to the high number of applications in renewable energy systems. Consequently, the importance of improving the efficiency of the hybrid converters has been highlighted. An optimal control strategy is a significant solution to handle the challenges of controlling the hybrid interleaved boost–Cuk converter. In this article, a modern‐optimization‐methods‐based PWM strategy for a hybrid power converter is developed. In order to improve the performance of the hybrid converter, four modern optimization algorithms—namely, Manta ray foraging optimization (MRFO), Marine Predators Algorithm (MPA), Jellyfish Search Optimizer (JS), and Equilibrium Optimizer (EO)—are employed to …


An Explicit Time-Domain Finite-Element Boundary Integral Method For Analysis Of Electromagnetic Scattering, Ming Dong, Liang Chen, Lijun Jiang, Ping Li, Hakan Bagci Jul 2022

An Explicit Time-Domain Finite-Element Boundary Integral Method For Analysis Of Electromagnetic Scattering, Ming Dong, Liang Chen, Lijun Jiang, Ping Li, Hakan Bagci

Electrical and Computer Engineering Faculty Research & Creative Works

A numerical scheme, which hybridizes the element-level dual-field time-domain finite-element domain decomposition method (ELDDM) and the time-domain boundary integral (TDBI) method to accurately and efficiently analyze open-region transient electromagnetic scattering problems, is proposed. Element-level decomposition decouples Maxwell equations on a discretization element from those on its neighboring elements using equivalent currents defined on their faces. For any element inside the computation domain, the equivalent currents are obtained from fields in the neighboring elements. For any element on the boundary of the computation domain, the equivalent currents are obtained using the fields generated by TDBI. To generate these fields, TDBI 'radiates' …


Experimentation And Correlation Development Of Mass Transfer In A Mimicked Fischer–Tropsch Slurry Bubble Column Reactor, Lu Han, Mahmoud M. Taha, Premkumar Kamalanathan, Nora Y. Selem, Muthanna H. Al-Dahhan Jul 2022

Experimentation And Correlation Development Of Mass Transfer In A Mimicked Fischer–Tropsch Slurry Bubble Column Reactor, Lu Han, Mahmoud M. Taha, Premkumar Kamalanathan, Nora Y. Selem, Muthanna H. Al-Dahhan

Chemical and Biochemical Engineering Faculty Research & Creative Works

Gas–liquid volumetric mass transfer coefficient "kLa " for CH4, CO2, and Ar were experimentally measured at different conditions in a mimicked Fischer–Tropsch (FT) slurry bubble column reactor by using a non-invasive gaseous tracer technique and the axial dispersion model. Results validate the square root relation, between kLa and diffusivity "Dg", that can be used to predict kLa for different species with k La values available in the literature. Additionally, Higbie's penetration theory was adopted along with bubble dynamics parameters estimation to develop a correlation for predicting kL …


In-Situ Infrared Thermographic Inspection For Local Powder Layer Thickness Measurement In Laser Powder Bed Fusion, Tao Liu, Cody S. Lough, Hossein Sehhat, Yi Ming Ren, Panagiotis D. Christofides, Edward C. Kinzel, Ming-Chuan Leu Jul 2022

In-Situ Infrared Thermographic Inspection For Local Powder Layer Thickness Measurement In Laser Powder Bed Fusion, Tao Liu, Cody S. Lough, Hossein Sehhat, Yi Ming Ren, Panagiotis D. Christofides, Edward C. Kinzel, Ming-Chuan Leu

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The laser powder bed fusion (LPBF) process is strongly influenced by the characteristics of the powder layer, including its thickness and thermal transport properties. This paper investigates in-situ characterization of the powder layer using thermographic inspection. A thermal camera monitors the temperature history of the powder surface immediately after a layer of new powder is deposited by the recoating system. During this process, thermal energy diffuses from the underlying solid part, eventually raising the temperature of the above powder layer. Guided by 1D modeling of this heat-up process, experiments show how the parameterized thermal history can be correlated with powder …