Engineering Commons^™

Large Scale Dataset Of Real Space Electronic Charge Density Of Cubic Inorganic Materials From Density Functional Theory (Dft) Calculations, Fancy Qian Wang, Kamal Choudhary, Jianjun Hu, Ming Hu

Faculty Publications

Driven by the big data science, material informatics has attracted enormous research interests recently along with many recognized achievements. To acquire knowledge of materials by previous experience, both feature descriptors and databases are essential for training machine learning (ML) models with high accuracy. In this regard, the electronic charge density ρ(r), which in principle determines the properties of materials at their ground state, can be considered as one of the most appropriate descriptors. However, the systematic electronic charge density ρ(r) database of inorganic materials is still in its infancy due to the difficulties in …

Natural Biomaterial Honey-Based Resistive Switching Device For Artificial Synapse In Neuromorphic Systems, Brandon Sueoka, Kuan Yew Cheong, Feng Zhao

Electrical and Computer Engineering Faculty Research & Creative Works

Resistive switching is a promising technology for artificial synapses, the most critical component and building block of a neural network for brain-inspired neuromorphic computing. The artificial synapse is capable of emulating a signal process and memory functions of biological synapses. The artificial synapse fabricated by natural bioorganic materials is essential for developing soft, flexible, and biocompatible electronics and sustainable, biodegradable, and environmentally friendly neuromorphic systems. In this work, a natural biomaterial - honey based resistive switching device - was demonstrated to emulate some important functionalities of biological synapses, including synaptic potentiation and depression, short-term and long-term memory, spatial summation, and …

Auto-Ethnographic Reflections: Lessons From Leading A Stem Initiative For Girls In School While We Ourselves Were In School, Kayli Heather Battel, Kritin Mandala, Sreyoshi Bhaduri, Natalie Anna Foster, Lilianny Virguez, Lissa Erickson, Krishna Pakala

Mechanical and Biomedical Engineering Faculty Publications and Presentations

In this paper, we use an auto-ethnographic approach to describe first-hand the reflections and learnings from leading an organization to help school children, especially girls, familiarize themselves with STEM and Cyber Security. The primary authors and ethnographers are founders of STEM initiatives for young learners. The primary author is a recent high school graduate who has taken up an engineering field, and two other contributing authors are high-schoolers currently leading these initiatives. With help from the three engineering educators on our authorship team, we use our individual self-narratives to develop a set of recommendations for other young engineering educators across …

Design, Dynamic Performance And Ecological Efficiency Of Fiber-Reinforced Mortars With Different Binder Systems: Ordinary Portland Cement, Limestone Calcined Clay Cement And Alkali-Activated Slag, Wu Jian Long, Zhuorui Wu, Kamal Khayat, Jingjie Wei, Biqin Dong, Feng Xing, Jinrui Zhang

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The dynamic mechanical properties and ecological efficiency of cement-based composites are of vital importance to the development of green building materials and dynamic loadings resistance. In this study, the dynamic mechanical properties, ecological and economic efficiency of fiber-reinforced mortars (FRMs) made with different binder systems, including ordinary Portland cement (OPC), limestone calcined clay cement (LC3), and alkali-activated slag (AAS), were compared. In addition, different rheological parameters were designed to evaluate the dynamic mechanical properties of FRMs. The fiber pull-out testing, Barrett-Joyner-Halenda (BJH) testing, and scanning electron microscope (SEM) were used to reveal the difference in the dynamic mechanical properties of …

Flipping The Digital Switch: Affective Responses Of Stem Undergraduates To Emergency Remote Teaching During The Covid-19 Pandemic, Angela Minichiello, Oenardi Lawanto, Wade Goodridge, Assad Iqbal, Muhammad Asghar

Engineering Education Student Research

The Corona Virus Disease-2019 (COVID-19) catalyzed a global shift to distance education known as an emergency transition to remote teaching (ERT). While prior research investigates students' experiences during traditional online learning, fewer studies examine students' affective responses (i.e., feelings, emotions) to those experiences, particularly when remote learning is unexpected and unplanned. To understand how science, technology, engineering, and mathematics (STEM) undergraduates responded affectively to the COVID-19 ERT, researchers generated open-ended survey data with 1340 undergraduates (253 female) in 27 courses across seven U.S. institutions. Using an inductive qualitative approach, researchers developed a three-tier thematic model to synthesize the self-reported reasons …

Opportunities From Disruption: How Lifelong Learning Helped Create More Connected Classrooms, Krishna Pakala, Sreyoshi Bhaduri

Mechanical and Biomedical Engineering Faculty Publications and Presentations

The coronavirus pandemic has led to instructors worldwide seeking ways to engage students better through virtual platforms. As the world interacts online, more than ever before, this paper reflects on an educator’s experience with the virtual teaching and learning spaces pre and during the ongoing pandemic. Autoethnography is a research methodology that analyzes a phenomenon through the use of self-narratives, which would otherwise remain private or buried. This paper uses an autoethnographic approach to describe first-hand. the experiences and learnings of an educator at a Western US Public University. This paper describes how first as an international student, a first …

Development Of Intensity-Duration-Frequency (Idf) Models For Manually Operated Rain Gauge Catchment: A Case Study Of Port Harcourt Metropolis Using 50 Years Rainfall Data, Francis Ogbozige

Tanzania Journal of Engineering and Technology (TJET)

Hydraulic structures such as surface drainages and culverts are usually constructed in urban areas with the intention of draining runoff into nearby streams and rivers in order to avoid flooding. However, most of these structures frequently fail to serve the intended use due to the occurrence of high intensity rainfall accompanied with long duration, which produce runoff discharge higher than their designed capacities. This is common in many developing countries as drainages and culverts are most times constructed without considering hydrological analysis of the catchment. Hence, this research considered Port Harcourt city as a case study by utilizing 50 years …

Real-Time Complex Hand Gestures Recognition Based On Multi- Dimensional Features, Isack Bulugu

Tanzania Journal of Engineering and Technology (TJET)

Gesture recognition is broadly utilized within the field of sensing. There are basically three gesture recognition methods based on computer vision, depth sensor and motion sensor. Motion sensor-based gesture recognition has few input data, fast speed, and direct access to three- dimensional information of the hand. The advantages of traditional motion sensor-based gesture recognition have gradually become a current research hotspot. The essence of traditional motion sensor-based gesture recognition is a pattern recognition problem, and its accuracy depends heavily on the feature dataset extracted from prior experience. Unlike traditional pattern recognition methods, deep learning can be used to a large …

Resilient Modulus Of Siliciclastic Unbound Granular Materials Under Repeated Wheel Loading, Siya Rimoyi

Tanzania Journal of Engineering and Technology (TJET)

The Resilient Modulus (Mr) is a fundamental material property input in modern Mechanistic-Empirical (M-E) pavements structural design. Empirical pavement design methods have been in use over a long period during which large databases of four- days-soaked California Bearing Ratio (CBR) values at or near the Maximum Dry Density have been generated in the strength assessments for Unbound Granular Materials (UGMs). In the adoption of the M-E design approach researchers have so far attempted with various degrees of success to develop models to derive resilient modulus from the conventional CBR-based databases. This study provides an extensive laboratory experimental study to investigate …

Economic Analysis Of Islanded Microgrid: A Case Study Of Kisiju Village - Coastal Region, Jackson Justo

Tanzania Journal of Engineering and Technology (TJET)

The concept of Microgrid (MG) has gained significant attention of researchers and projects on the business side of electrical power generation and utilization, particularly in electrification of islanded areas such as villages. Most of these microgrids are powered by renewable energy resources (RERs) and they distribute power in low voltage distribution networks. Hence, these systems are faced with reliability problems due to the intermittency nature of RERs which affect the technical as well as the return on Investment of specific projects. In the latter context, reliability and economic analysis of the MG systems is an inevitable choice. This paper presents …

Spatial And Temporal Variation Of Selected Water Quality Parameters In The Tanzanian Side Of Lake Victoria, Richard Joseph Kimwaga

Tanzania Journal of Engineering and Technology (TJET)

Lake Victoria’s water quality is increasingly becoming under heavy pressure mainly due to land based activities and aerial inputs which are taking place within the basin. This study was carried out to assess the spatial, including vertical and temporal, variation of the water quality of Lake Victoria on the Tanzanian side. Historical water quality data for the period from 2000 to 2016 was collected. Temperature, pH, Dissolved Oxygen (DO) and Turbidity were selected for study since they are the mostly measured and monitored water quality parameters. Land use-land cover changes were analysed using ArcGIS. ILWIS 3.7 software was used to …

Complete Neighbourhood Search Heuristic Algorithm For Portfolio Optimization, Collether John

Tanzania Journal of Engineering and Technology (TJET)

In portfolio optimization, the fundamental goal of an investor is to optimally allocate investments between different assets. Mean-variance optimization methods make unrealistic assumptions to solve the problem of optimal allocation. On the other hand, when realistic constraints like holding size and cardinality are introduced it leads to optimal asset allocation which differ from the mean variance optimization. The resulting optimization problem become quite complex as it exhibits multiple local extrema and discontinuities. Heuristic algorithms work well for the complex problem. Therefore, a heuristic algorithm is developed which is based on hill climbing complete (HC-C). It is utilized to solve the …

Observing Empathy In Informal Engineering Activities With Girls Ages 7–14, Susan M. Letourneau, Dorothy T. Bennett, Changchia Liu, Yessenia Argudo, Kylie Peppler, Anna Keune, Maggie Dahn, Katherine Mcmillan Culp

Journal of Pre-College Engineering Education Research (J-PEER)

Empathy is a critical part of the engineering design process. It allows engineers to more deeply understand their clients’ perspectives and design solutions that meet the needs of diverse stakeholders. Studies also show that reframing engineering education to prioritize empathy for others can counteract stereotypes of engineering as impersonal and invite a wider range of identities into the field. This approach can help to address persistent gender disparities in engineering, which reflect a need for engineering education to increase its efforts to include girls’ perspectives. Informal learning environments have developed strategies for framing engineering problems in human-centered ways, but more …

Influence Of Site And System Parameters On The Performance Of Roof-Top Grid-Connected Pv Systems Installed In Harlequins, Belfast, Northern Ireland, Chibuisi Chinasaokwu Okorieimoh, Brian Norton, Michael Conlon, Desmond Lalor, Ciaran Mcnamara

Other Resources

The problem of energy scarcity has hit a global scale because of the dependency of most of the energy generation on non-renewable sources (e.g., fossil fuels). As in supply and demand laws, the lower the amount of energy provided, the more expensive it becomes, causing a major problem for the industry in general, which is dependent on it. These non-renewable energy sources contribute to environmental degradation effects and depletion of the ozone layer from the atmosphere. To reduce this effect, the use of renewable energy sources which is environmentally friendly has been on the growing index across the globe.

Solar …

Age Specific Models To Capture The Change In Risk Factor Contribution By Age To Short Term Primary Ischemic Stroke Risk, Elizabeth Hunter, John D. Kelleher

Articles

Age is one of the most important risk factors when it comes to stroke risk prediction. However, including age as a risk factor in a stroke prediction model can give rise to a number of difficulties. Age often dominates the risk score, and also not all risk factors contribute proportionally to stroke risk by age. In this study we investigate a number of common stroke risk factors, using Framingham heart study data from the NHLBI Biologic Specimen and Data Repository Information Coordinating Center to determine if they appear to contribute proportionally by age to a stroke risk score. As we …

Comparison Of Dye Wastewater Treatment Methods: A Review., Bukola M. Adesanmi, Yung-Tse Hung, Howard Paul, Christopher Huhnke

Civil and Environmental Engineering Faculty Publications

Wastewater is produced by numerous dyes producing and dye consuming industries in their process activities especially the textile industry. These effluents become toxic and harmful to the living things and the environment if not properly treated before being discharged to the environment. In recent decades dye wastewater has been becomes a growing water pollution problem because it is one of the most difficult to treat. To put an end to this problem, viable, efficient, and sustainable method of treatment of dye wastewater and color removal needs to be established. Several research papers have been done over the years on various …

Effect Of Processing Parameters And Build Orientation On Microstructure And Performance Of Aisi Stainless Steel 304l Made With Selective Laser Melting Under Different Strain Rates, Tan Pan, Xinchang Zhang, Aaron Flood, Sreekar Karnati, Wei Li, Joseph William Newkirk, Frank W. Liou

Materials Science and Engineering Faculty Research & Creative Works

Selective laser melting (SLM) process allows greater geometry flexibility; therefore, it has become more widespread in its deployment in the industry for fabricating metal alloys. However, a material characterization study is needed in order to understand better the correlation between the process, microstructure, and performance. In the current study, the raw SLM fabricated AISI stainless steel 304 L was fabricated with different processing parameters and build orientations (horizontal, inclined, and vertical). The tensile behavior was evaluated under different strain rates (0.0001/s, 0.001/s, 0.01/s, and 0.1/s) and then compared to commercial cold-rolled and annealed counterparts. Grain structures, tensile strength, elongation-to-failure, strain …

State Of Industry 5.0—Analysis And Identification Of Current Research Trends, Aditya Akundi, Daniel Euresti, Sergio Luna, Wilma Ankobiah, Amit Lopes, Immanuel Edinbarough

Manufacturing & Industrial Engineering Faculty Publications

The term Industry 4.0, coined to be the fourth industrial revolution, refers to a higher level of automation for operational productivity and efficiency by connecting virtual and physical worlds in an industry. With Industry 4.0 being unable to address and meet increased drive of personalization, the term Industry 5.0 was coined for addressing personalized manufacturing and empowering humans in manufacturing processes. The onset of the term Industry 5.0 is observed to have various views of how it is defined and what constitutes the reconciliation between humans and machines. This serves as the motivation of this paper in identifying and analyzing …

Accident Analysis Of Mining Industry In The United States – A Retrospective Study For 36 Years, Elham Rahimi, Younes Shekarian, Naser Shekarian, Pedram Roghanchi

Journal of Sustainable Mining

A retrospective study on accident analysis of the United States mines for 36 years was achieved using statistical analysis on the MSHA's accident databases between 1983 and 2018. A regression model of generalized estimation equation (GEE) was used for unbalanced panel data that provided 95,812 observations for 19,924 mine-ID-year in aggregate, coal, metal, and non-metal mines. The contributions of various parameters, including mine type, injured body part, days lost, age, and experience on the rate of accidents and injuries were investigated across the commodity types. The results showed coal miners in the East region are at a higher risk of …

Tools & Visualization Techniques Available To Support The Operations Manager, Kirk Michealson

Operations Management Presentations

Most organizations provide their employees the Microsoft Office Tools Suite with Excel. The University of Arkansas Master of Science in Operations Management (MSOM) Program has included Excel as a foundational aspect of the program for the last 7 years. In that time, Microsoft has increased the Excel capabilities dramatically. Simultaneously, business intelligence analytics interest has increased, and Tableau has been created as a visual analytics platform to help users see and understand data for modern business intelligence. As a result, to support the Operations Manager the MSOM Program has developed a new course to present the additional tools and visualization …

Biomechanical Evaluation Of Recurrent Dissociation Of Modular Humeral Prostheses, Daniel B. Luckenbill, Mike F. Iossi, Alyssa M. George Whitney, Danielle Miller, Lynn A. Crosby, Tarun Goswami

Biomedical, Industrial & Human Factors Engineering Faculty Publications

The purpose of the study was to evaluate the force and torque required to dissociate a humeral head from the unimplanted modular total shoulder replacement system from different manufacturers and to determine if load and torque to dissociation are reduced in the presence of bodily fluids. Impingement, taper contamination, lack of compressive forces, and interference of taper fixation by the proximal humerus have all been reported as possible causes for dissociation. Experimental values determined in this research were compared with literature estimates of dissociation force of the humeral head under various conditions to gain more understanding of the causes of …

Wettability Alteration Process At Pore-Scale During Engineered Waterflooding Using Computational Fluid Dynamics, Yongqiang Chen, Ping Chang, Guang Xu, Quan Xie

Mining Engineering Faculty Research & Creative Works

Engineered waterflooding modifies chemistry of injected brine to efficiently and environmentally friendly enhance oil recovery. The common practice of engineered waterflooding includes low salinity waterflooding (LSW) and carbonated waterflooding. Among these oil recovery methods, wettability alteration has been perceived as a critical physicochemical process for additional oil recovery. While extensive work has been conducted to characterize the wettability alteration, the existing theory cannot explain the conflict oil recovery between secondary mode (injecting engineered water at the very beginning of flooding) and tertiary mode (injecting engineered water after conventional waterflooding), where secondary engineered waterflooding always gives a greater incremental oil recovery …

Open-Loop Control Of Electrostatic Levitation Actuators To Enhance The Travel-Range Of Optical Switches, Mohammad Mousavi, Mohammad Alzgool, Daniel Lopez, Shahrzad Towfighian

Mechanical Engineering Faculty Scholarship

Command shaping is a driving technique for handling the large settling time of the high-Q-MEMS actuators. The strong nonlinearity due to the electrostatic actuation limits the linear operation range in cantilevered or torsional micro-mirrors where command shaping techniques can be applied for positioning. Experimental and simulation results of this research demonstrate the effectiveness of using electrostatic levitation to overcome the actuation nonlinearities and a significant increase in the operation range. The motivation for this research is that applying the nonlinear command shaping causes complexity in command manipulation and requires an accurate knowledge of the nonlinear terms involved in the system …

Implication Of Production Tax Credit On Economic Dispatch For Electricity Merchants With Storage And Wind Farms, Jian Liu, Meng Ou, Xinyue Sun, Jian Chen, Chuanmin Mi, Rui Bo

Electrical and Computer Engineering Faculty Research & Creative Works

The production tax credit (PTC) promotes wind energy development, reduces power generation costs, and can affect merchants' joint economic dispatch, particularly for electricity merchants with both energy storage and wind farms. Two common PTC policies are studied – in the first policy, a wind farm receives PTC by selling wind generation to the market and its storage can be used to store energy from the wind generation and energy purchased from the grid but the energy released from the storage cannot receive PTC; in the second policy, the energy released from the storage can also qualify for PTC but purchasing …

Descriptive Statistical Analysis Of Experimental Data For Wettability Alteration With Surfactants In Carbonate Reservoirs, Ya Yao, Mingzhen Wei, Baojun Bai

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Surfactants have been the widely used agents to alter the wettability of carbonate rocks to more water-wet and enhanced oil recovery (EOR). As one of major EOR methods, an effective surfactant huff-puff application design requires comprehensive guidelines about where, how, and when this method could be applied. In order to construct such guidelines, a dataset including 338 effective surfactant imbibition tests is established by collecting information from nearly 50 publications. Based on this dataset, descriptive statistical analysis methods are used to conduct data analysis, including three main parts. The first part establishes the application guidelines for surfactant huff-puff treatments which …

The Effect Of Sodium Polymethacrylate On The Rheology Of The Positive Paste And Performance Of The Lead-Acid Battery, Julian Kosacki, Dimitri Feys, Fatih Dogan

Materials Science and Engineering Faculty Research & Creative Works

No abstract provided.

Detonation Synthesis Of Nanoscale Silicon Carbide From Elemental Silicon, Martin J. Langenderfer, Yue Zhou, Jeremy Lee Watts, William Fahrenholtz, Catherine E. Johnson

Materials Science and Engineering Faculty Research & Creative Works

Direct reaction of precursors with the products of detonation remains an underexplored area in the ever-growing body of detonation synthesis literature. This study demonstrated the synthesis of silicon carbide during detonation by reaction of elemental silicon with carbon products formed from detonation of RDX/TNT mixtures. Continuum scale simulation of the detonation showed that energy transfer by the detonation wave was completed within 2–9 μs depending on location of measurement within the detonating explosive charge. The simulated environment in the detonation product flow beyond the Chapman-Jouguet condition where pressure approaches 27 GPa and temperatures reach 3300 K was thermodynamically suitable for …

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

Materials Science and Engineering Faculty Research & Creative Works

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

Micelles Inhibit Electro-Oxidation Degradation Of Nonylphenol Ethoxylates, Yangyuan Ji, Junfeng Niu, Yuhang Fang, Alliyan Tan Nou, David M. Warsinger

School of Mechanical Engineering Faculty Publications

Nonylphenol ethoxylates (NEPOs) are widely used as nonionic surfactant in the industry, which pose a threat to environment and human health. In this study, we conducted kinetic experiments and chemical analysis to investigate the effects of NEPOs micelles on degradation kinetics and electro-oxidation degradation mechanism. The electro-oxidation degradation of NEPOs followed pseudo-first order kinetics and more than 92% of NEPOs was degraded. Furthermore, the hydroxyl radicals generated by the Ti4O7 anode contributed to 41% of degradation performance. During the entire degradation process, the micelles of NEPOs undergo growth, and the steric hindrance phenomenon of micelles prevents NEPOs from being attack …

Analytical, Simulation, And Experimental Study Of The Generation Of Multiple Beams For Application To A Traveling Wave Tube(Twt), Khandakar Nusrat Islam

Electrical and Computer Engineering ETDs

The traveling wave tube (TWT) has been a reliable conventional vacuum electron device (VED) since the 1940s. Researchers, beginning in the late 1980s, extended the TWT to the relativistic electron beam regime to generate 100s MW power in X-band. Since the mid-1990s there has been little advancement in the field. Recently, the linear theory of a multi-stream TWT was published that showed super-exponential amplification properties. This study describes a novel technique for producing multiple electron beams with energy difference of about 4-31% with comparable currents from a single cathode at a single potential for a multi-stream TWT. This work presents …