Digital Commons Network^™

Interlude: Interactions Between Labeled And Unlabeled Data To Enhance Semi-Supervised Learning, Zhe Huang, Xiaowei Yu, Dajiang Zhu, Michael C. Hughes

Computer Science Faculty Research & Creative Works

Semi-supervised learning (SSL) seeks to enhance task performance by training on both labeled and unlabeled data. Mainstream SSL image classification methods mostly optimize a loss that additively combines a supervised classification objective with a regularization term derived solely from unlabeled data. This formulation often neglects the potential for interaction between labeled and unlabeled images. In this paper, we introduce InterLUDE, a new approach to enhance SSL made of two parts that each benefit from labeled-unlabeled interaction. The first part, embedding fusion, interpolates between labeled and unlabeled embeddings to improve representation learning. The second part is a new loss, grounded in …

Core-Periphery Multi-Modality Feature Alignment For Zero-Shot Medical Image Analysis, Xiaowei Yu, Lu Zhang, Zihao Wu, Dajiang Zhu

Computer Science Faculty Research & Creative Works

Multi-modality learning, exemplified by the language-image pair pre-trained CLIP model, has demonstrated remarkable performance in enhancing zero-shot capabilities and has gained significant attention recently. However, simply applying language-image pre-trained CLIP to medical image analysis encounters substantial domain shifts, resulting in severe performance degradation due to inherent disparities between natural (non-medical) and medical image characteristics. To address this challenge and uphold or even enhance CLIP's zero-shot capability in medical image analysis, we develop a novel approach, Core-Periphery feature alignment for CLIP (CP-CLIP), to model medical images and corresponding clinical text jointly. To achieve this, we design an auxiliary neural network whose …

Enhancing Group-Wise Consistency In 3-Hinge Gyrus Matching Via Anatomical Embedding And Structural Connectivity Optimization, Chao Cao, Xiaowei Yu, Lu Zhang, Tong Chen, Yanjun Lyu, Tianming Liu, Dajiang Zhu

Computer Science Faculty Research & Creative Works

Recently, a novel cortical folding pattern known as the 3-hinge gyrus (3HG) has been identified. 3HGs are defined as the convergence of the gyri coming from three distinct directions on gyral crests. In contrast to cortical regions, 3HGs are defined at a finer scale and they widely exist across different individuals, representing both commonalities and individualities of cortical folding patterns. It is important to note that 3HGs are identified in individual spaces, lacking natural cross-subject correspondences. To address this issue, we have developed a learning-based method to encode anatomical features of 3HGs into a set of embedding vectors that can …

The Perils Of Wi-Fi Spoofing Attack Via Geolocation Api And Its Defense, Xiao Han, Junjie Xiong, Wenbo Shen, Mingkui Wei, Shangqing Zhao, Zhuo Lu, Yao Liu

Computer Science Faculty Research & Creative Works

Location spoofing attack deceiving a Wi-Fi positioning system has been studied for over a decade. However, it has been challenging to construct a practical spoofing attack in urban areas with dense coverage of legitimate Wi-Fi APs. This paper identifies the vulnerability of the Google Geolocation API, which returns the location of a mobile device based on the information of the Wi-Fi access points that the device can detect. We show that this vulnerability can be exploited by the attacker to reveal the black-box localization algorithms adopted by the Google Wi-Fi positioning system and easily launch the location spoofing attack in …

Modeling And Analysis Of Dc-Dc Converters For Power Distribution Networks Design, Junho Joo

Doctoral Dissertations

"Accurate modeling of power distribution networks (PDN) including voltage regulator module (VRM) is critical for high-performance digital systems including low- to high-power applications such as laptops and mobile platforms. As a consolidated end-to-end power source, PDN can be divided into several parts: the VRM to regulate the external voltage source, printed circuit board (PCB) PDN, package PDN, and on-chip PDN. A transient current drawn from the on-die circuitry will produce an instantaneous voltage drop at the bump. The time domain behavior of such a drop and the subsequent recovery is called voltage droop which is strongly associated with the VRM …

Modeling And Control For Precision Robotic Machining, Patrick Bazzoli

Doctoral Dissertations

"Robots are used in a wide variety of manufacturing applications, but machining applications in which robots can excel are limited by their lower accuracy and stiffness relative to traditional CNC machines. This work is composed of two parts: one to evaluate a robot’s accuracy and one to compensate for the vibrations of the robot due to its lower stiffness.

In order to evaluate whether a robot has the necessary accuracy to perform a given machining task, Paper 1 discusses a novel Model Invalidation method. This methodology provides a statistical framework as well as a measurement strategy for determining if a …

Trends And Opportunities For Material Information Sharing: Applying Bim To Support Supply Chain Management In Construction Projects, Seog Jae Choi, Fernanda Leite

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Due to dynamic organizations and unexpected conditions on project sites, the construction industry has suffered from schedule and cost overruns. Researchers have applied building information modeling (BIM) and supply chain management (SCM) concepts to integrate diverse stakeholders, and further, improve efficiency in construction projects. BIM can support supply chain integration (SCI) by providing reliable up-to-date information on a project, which reduces resource waste and completes the project as planned. Specifically, sharing updated material information, including the state of material fabrication, current location, each material's due date on site, and site inventory status, is crucial for successful project execution because such …

Project Wars: A Serious Game To Teach Decision Making In Project Execution, Cecil Eng Huang Chua, Veda C. Storey, Linda Wallace

Business and Information Technology Faculty Research & Creative Works

Project execution (i.e., the production, delivery, and deployment of an information system project's outputs) is a difficult concept to teach effectively because of the many real-time decision-making variables facing a project manager. This paper introduces Project Wars, a web-based serious game designed to teach the project execution concepts of deferral of gratification, organizational mindfulness, and discipline in the face of adversity. Project Wars serves as both a platform to instill these concepts and as a basis for discussions on other critical concepts. The latter includes project team management and control, project leadership, the relationship between productivity, slack, and overtime, and …

Information Extraction From The Reviews Of Ai Applications Using Sas Text Mining Process, Imranul Kabir Chowdhury, Wen Bin Yu

Business and Information Technology Faculty Research & Creative Works

The recent surge in AI advancements, particularly generative AI, has grabbed the attention of major tech companies who are all striving to integrate it seamlessly into their products. This highlights the need to evaluate the various AI products on the market and identify the features that resonate most with users. SAS Enterprise Miner, a powerful text analysis tool, can be used to uncover hidden insights from user reviews. In this study, we will leverage various SAS functions to analyze reviews of different AI applications. By analyzing these reviews, we aim to pinpoint the unique strengths of these AI applications and …

A Comparative Study Of Cationic Copper(I) Reagents Supported By Bipodal Tetramethylguanidinyl-Containing Ligands As Nitrene-Transfer Catalysts, Suraj Kumar Sahoo, Brent Harfmann, Himanshu Bhatia, Harish Singh, Srikanth Balijapelly, Amitava Choudhury, Pericles Stavropoulos

Chemistry Faculty Research & Creative Works

The Bipodal Compounds [(TMG2biphenN-R)CuI-NCMe](PF6) (R = Me, Ar (4-CF3Ph-)) And [(TMG2biphenN-Me)CuI-I] Have Been Synthesized With Ligands That Feature A Diarylmethyl- And Triaryl-Amine Framework And Superbasic Tetramethylguanidinyl Residues (TMG). The Cationic Cu(I) Sites Mediate Catalytic Nitrene-Transfer Reactions Between The Imidoiodinane PhI = NTs (Ts = Tosyl) And A Panel Of Styrenes In MeCN, To Afford Aziridines, Demonstrating Comparable Reactivity Profiles. The Copper Reagents Have Been Further Explored To Execute C-H Amination Reactions With A Variety Of Aliphatic And Aromatic Hydrocarbons And Two Distinct Nitrene Sources PhI = NTs And PhI = NTces (Tces = 2,2,2-Trichloroethylsulfamate) In Benzene/HFIP (10:2 V/v). Good Yields …

Perfect Polar Alignment Of Parallel Beloamphiphile Layers: Improved Structural Design Bias Realized In Ferroelectric Crystals Of The Novel “Methoxyphenyl Series Of Acetophenone Azines”, Harmeet Bhoday, Nathan Knotts, Rainer Glaser

Chemistry Faculty Research & Creative Works

An Improved Design Is Described For Ferroelectric Crystals And Implemented With The "Methoxyphenyl Series" Of Acetophenone Azines, (MeO−Ph, Y)-Azines With Y=F (1), Cl (2), Br (3), Or I (4). The Crystal Structures Of These Azines Exhibit Polar Stacking Of Parallel Beloamphiphile Monolayers (PBAMs). Azines 1, 3, And 4 Form True Racemates Whereas Chloroazine 2 Crystallizes As A Kryptoracemate. Azines 1–4 Are Helical Because Of The N−N Bond Conformation. In True Racemates The Molecules Of Opposite Helicity (M And P) Are Enantiomers A(M) And A*(P) While In Kryptoracemates They Are Diastereomers A(M) And B*(P). The Stacking Mode Of PBAMs Is Influenced …

Solar Enhanced Oxygen Evolution Reaction With Transition Metal Telluride, Harish Singh, Taishi Higuchi-Roos, Fabrice Roncoroni, David Prendergast, Manashi Nath

Chemistry Faculty Research & Creative Works

The Photo-Enhanced Electrocatalytic Method of Oxygen Evolution Reaction (OER) Shows Promise for Enhancing the Effectiveness of Clear Energy Generation through Water Splitting by using Renewable and Sustainable Source of Energy. However, Despite Benefits of Photo electrocatalytic (PEC) Water Splitting, its Uses Are Constrained by its Low Efficiency as a Result of Charge Carrier Recombination, a Large overpotential, and Sluggish Reaction Kinetics. Here, We Illustrate that Nickel Telluride (NiTe) Synthesized by Hydrothermal Methods Can Function as an Extremely Effective Photo-Coupled Electrochemical Oxygen Evolution Reaction (POER) Catalyst. in This Study, NiTe Was Synthesized by Hydrothermal Method at 145°C within Just an Hour …

A Review Of Dielectric Barrier Discharge Cold Atmospheric Plasma For Surface Sterilization And Decontamination, Kolawole Adesina, Ta Chun Lin, Yue-Wern Huang, Marek Locmelis, Daoru Frank Han

Biological Sciences Faculty Research & Creative Works

Numerous investigations have shown that non-equilibrium discharges at atmospheric pressure, also known as "cold atmospheric plasma" (CAP) are efficient to remove biological contaminants from surfaces of a variety of materials. Recently, CAP has quickly advanced as a technique for microbial cleaning, wound healing, and cancer therapy due to the chemical and biologically active radicals it produces, known collectively as reactive oxygen and nitrogen species (RONS). This article reviews studies pertaining to one of the atmospheric plasma sources known as Dielectric Barrier Discharge (DBD) which has been widely used to treat materials with microbes for sterilization, disinfection, and decontamination purposes. To …

Bioprinting With Adipose Stem Cells And Hydrogel Modified With Bioactive Glass, Krishna C.R. Kolan, Apurv Saxena, Bradley A. Bromet, Lesa B. Steen, August T. Bindbeutel, Julie A. Semon, Delbert E. Day, Ming C. Leu

Biological Sciences Faculty Research & Creative Works

Bioprinting research is focused on utilizing growth factors and multiple cell types to create clinically relevant three-dimensional (3D) tissue models using hydrogels. Rheological and biological challenges are two main factors that limit the creation of extrudable bioactive hydrogels. In this study, we investigate incorporation of fast dissolving and bioactive borate glass in different weight to volume percentages (0.075 to 0.6%) to alginate-gelatin (1:1) hydrogel to improve rheological properties and enable bioprinting with bioactive glass. The addition of glass improved the stiffness of the hydrogel. Human adipose-derived mesenchymal stem cells (ASCs) were uniformly mixed in this bioink at 1 x 106 …

Dna Origami-Assisted Regioselective Organization Of Anisotropic Gold Nanotriangle Clusters, Wenyan Liu, Prashant Gupta, Yuwei Zhang, Krishna Thapa, Srikanth Singamaneni, Risheng Wang

Chemistry Faculty Research & Creative Works

The manipulation of anisotropic nanoparticles, such as gold nanorods and nano prisms, has attracted great attention in nanotechnology due to their sensitive geometry-dependent properties. However. traditional synthesis and assembly methods for these particles face challenges in size uniformity and higher-order structuring. To address these limitations, this study presents a strategy using DNA origami triangles, not just as templates, but as encapsulating agents for gold nanotriangles (AuNTs). This method enables the construction of diverse nanoparticle clusters with precisely controlled distance and orientation. The formed clusters exhibit unique optical characteristics, demonstrated by UV-visible spectroscopy and supported by finite-difference time domain (FDTD) simulations. …

Selected Trace Element Uptake By Rice Grain As Affected By Soil Arsenic, Water Management And Cultivar -A Field Investigation, Eric M. Farrow, Jianmin Wang, Honglan Shi, John Yang, Bin Hua, Baolin Deng

Chemistry Faculty Research & Creative Works

Accumulation of arsenic (As) in rice grain was reported in many regions of the world, including the United States, which has been a threat to human health. This field research investigated the grain As accumulation and its relationship with the uptake of selenium (Se), molybdenum (Mo), and cadmium (Cd) in soils with and without monosodium methane arsonate (MSMA) amended, as effects of selected rice cultivars and water management. Results indicated that MSMA increased the accumulation of As and Se but decreased Mo for all six cultivars under four irrigation management. MSMA also increased grain-Cd in some cultivars. In no MSMA-amended …

High-Capacity Anode For Sodium-Ion Batteries Using Hard Carbons Derived From Polyurea-Cross-Linked Silica Xerogel Powders, Santhoshkumar Sundaramoorthy, Rushi U. Soni, Stephen Yaw Owusu, Sutapa Bhattacharya, A. B.M.Shaheen Ud Doulah, Vaibhav A. Edlabadkar, Chariklia Sotiriou-Leventis, Amitava Choudhury

Chemistry Faculty Research & Creative Works

In this article, we demonstrated carbon aerogel-silica composites derived from polyurea-cross-linked silica xerogel powders (C-PUA@silica) as anodes for Na-ion batteries. These xerogel-derived hard carbons with embedded silica showed a stable high capacity. Of the several hard carbon samples derived at different temperatures, the pyrolyzed sample at 800 °C (C-PUA@silica-800) showed a high capacity of 236 mAh/g at a current density of 10 mA/g and a stable cycle-life at 200 mAh/g. The galvanostatic charge-discharge curves displayed a sloping voltage profile reminiscent of the adsorption mechanism of Na+ storage. On the other hand, higher temperature-pyrolyzed samples at 1300 °C (C-PUA@silica-1300) displayed a …

Boosting The Microbial Electrosynthesis Of Formate By Shewanella Oneidensis Mr-1 With An Ionic Liquid Cosolvent, Ashwini Dantanarayana, Wassim El Housseini, Kevin Beaver, Monica Brachi, Timothy P. Mcfadden, Shelley D. Minteer

Chemistry Faculty Research & Creative Works

Microbial electrosynthesis (MES) is a rapidly growing technology at the forefront of sustainable chemistry, leveraging the ability of microorganisms to catalyze electrochemical reactions to synthesize valuable compounds from renewable energy sources. The reduction of CO₂ is a major target application for MES, but research in this area has been stifled, especially with the use of direct electron transfer (DET)-based microbial systems. The major fundamental hurdle that needs to be overcome is the low efficiency of CO₂ reduction largely attributed to minimal microbial access to CO₂ owing to its low solubility in the electrolyte. With their tunable physical …

Flow Regimes In Bubble Columns With And Without Internals: A Review, Ayat N. Mahmood, Amer A. Abdulrahman, Laith S. Sabri, Abbas J. Sultan, Hasan Shakir Majdi, Muthanna H. Al-Dahhan

Chemical and Biochemical Engineering Faculty Research & Creative Works

Hydrodynamics characterization in terms of flow regime behavior is a crucial task to enhance the design of bubble column reactors and scaling up related methodologies. This review presents recent studies on the typical flow regimes established in bubble columns. Some effort is also provided to introduce relevant definitions pertaining to this field, namely, that of "void fraction" and related (local, chordal, cross-sectional and volumetric) variants. Experimental studies involving different parameters that affect design and operating conditions are also discussed in detail. In the second part of the review, the attention is shifted to cases with internals of various types (perforated …

Thermal Decomposition And Kinetic Parameters Of Three Biomass Feedstocks For The Performance Of The Gasification Process Using A Thermogravimetric Analyzer, Rania Almusafir, Joseph D. Smith

Chemical and Biochemical Engineering Faculty Research & Creative Works

Thermogravimetric analysis (TGA) is a powerful technique and useful method for characterizing biomass as a non-conventional fuel. A TGA apparatus has been utilized to experimentally investigate the impact of biomass feedstock diversity on the performance of the gasification of hardwood (HW), softwood (SW) pellets, and refuse-derived fuel (RDF) materials. The solid conversion rate and the volatile species formation rate have been estimated to quantify the rates of devolatilization for each material. In addition, the combustion kinetic characteristics of the three biomass feedstocks were investigated using TGA at different heating rates, and a thermal kinetic analysis was conducted to describe the …

Gas-Phase Adsorption Of Dimethyl Methylphosphonate Over Ce(Oh)4@Pim-1 Composites Prepared Via Matrix Incorporation And Surface Coating Methods, Sukanta K. Mondal, Peter O. Aina, Ali A. Rownaghi, Fateme Rezaei

Chemical and Biochemical Engineering Faculty Research & Creative Works

This Study Investigated the Potential of Polymer of Intrinsic Microporosity (PIM-1) and Ce(OH)4@PIM-1 Composites for Adsorption of the Nerve Agent Simulant, Dimethyl Methylphosphonate (DMMP). through Experimental Investigations It Was Demonstrated that These Composite Adsorbents Exhibit Excellent Gas-Phase DMMP Adsorption Performance, with High Uptake Capacities and Relatively Fast Kinetics. This Study Further Examined the Effect of Two Composite's Preparation Methods, Namely Matrix Incorporation and Surface Coating, on the DMMP Adsorption Performance of Ce(OH)4@PIM-1. the Results Revealed that Coating of Ce(OH)4 on the PIM-1 Surface Gives Rise to Faster Adsorption Kinetics Than its Incorporation into the Polymer Matrix at Fixed 30 Wt …

Liposomes-Encapsulating Double-Stranded Nucleic Acid (Poly I:C) For Head And Neck Cancer Treatment, Vidit Singh, Anna Chernatynskaya, Lin Qi, Hsin Yin Chuang, Tristan Cole, Vimalin Mani Jeyalatha, Lavanya Bhargava, W. Andrew Yeudall, Laszlo Farkas, Hu Yang

Chemical and Biochemical Engineering Faculty Research & Creative Works

Polyriboinosinic acid-polyribocytidylic acid (Poly I:C) serves as a synthetic mimic of viral double-stranded dsRNA, capable of inducing apoptosis in numerous cancer cells. Despite its potential, therapeutic benefits, the application of Poly I:C has been hindered by concerns regarding toxicity, stability, enzymatic degradation, and undue immune stimulation, leading to autoimmune disorders. To address these challenges, encapsulation of antitumor drugs within delivery systems such as cationic liposomes is often employed to enhance their efficacy while minimizing dosages. In this study, we investigated the potential of cationic liposomes to deliver Poly I:C into the Head and Neck 12 (HN12) cell line to induce …

Novel Modified Polyethersulfone High Temperature And Low Humidity Fuel Cell Membrane: Experimental And Simulation Study, Mohammed K. Al Mesfer, Muthanna H. Al-Dahhan, Mohd Danish, Mumtaj Shah

Chemical and Biochemical Engineering Faculty Research & Creative Works

The Present Study Focuses on Synthesizing a High-Temperature Stable Membrane Working under Low Relative Humidity (RH) by Aminating the Traditional Polyethersulfone Polymer with Aniline for Fuel Cell Applications. a Condensed-Phase Optimized Molecular Potentials for Atomistic Simulation Studies Force Field-Based Molecular Dynamics Simulation Was Used to Explore the Microscopic Properties and Transport of Water and Hydronium (H3O+) Ions Across the Electrolyte at Varied Temperatures and RHs. COMSOL Calculates Oxygen and Hydrogen Concentrations after Examining the Polymer–ion Interaction with the Radial Distribution Function (RDF). the High H3O+ Diffusion Coefficient of the Aniline-Treated Membrane Shows the Benefit of the Modification. the RDF Confirmed …

Robust Triso-Fueled Pebble Identification By Digit Recognition, Roshan Kenia, Jihane Mendil, Ahmed Jasim, Muthanna Al-Dahhan, Zhaozheng Yin

Chemical and Biochemical Engineering Faculty Research & Creative Works

Nuclear Power Plays a Vital Role in Providing Reliable and Clean Energy to Fulfill Increasing Demands in Electricity Worldwide. It Continues to Be an Essential Source of National Power Supply as Growing Concerns About Fossil Fuel Depletion, Global Warming, and Emissions Require Utilizing Sustainable Energy Sources. One Area Contributing to the Growth of Nuclear Power is the Development of Reactors that Have Enhanced Protection and Security, Thermal Efficiency, and Design. Reactor Efficiency Can Be Studied by the Burnup that Occurs When a TRISO-Fueled Pebble is Inserted into the Nuclear Core and Subsequently Removed. the Levels of Burnup Are Measured based …

Molecular Imaging Nanoprobes And Their Applications In Atherosclerosis Diagnosis, Huari Kou, Hu Yang

Chemical and Biochemical Engineering Faculty Research & Creative Works

Molecular imaging has undergone significant development in recent years for its excellent ability to image and quantify biologic processes at cellular and molecular levels. Its application is of significance in cardiovascular diseases, particularly in diagnosing them at early stages. Atherosclerosis is a complex, chronic, and progressive disease that can lead to serious consequences such as heart strokes or infarctions. Attempts have been made to detect atherosclerosis with molecular imaging modalities. Not only do imaging modalities develop rapidly, but research of relevant nanomaterials as imaging probes has also been increasingly studied in recent years. This review focuses on the latest developments …

Injectable Dendrimer Hydrogel Delivers Melphalan In Both Conjugated And Free Forms For Retinoblastoma, Remy C. Cooper, Juan Wang, Hu Yang

Chemical and Biochemical Engineering Faculty Research & Creative Works

We report the successful synthesis of an injectable dendrimer hydrogel (DH) carrying melphalan, a clinical drug for retinoblastoma treatment, in both conjugated and free forms. Polyamidoamine (PAMAM) dendrimer generation 5 (G5) is surface-modified with an acid-sensitive acetal-dibenzocyclooctyne linker and then undergoes azide-alkyne cycloaddition with melphalan-PEG-N3 conjugate to form G5-acetal-melphalan. During the DH gelation between G5-acetal-melphalan and PEG-diacrylate, free melphalan is added, resulting in a hydrogel (G5-acetal-melphalan-DH/melphalan) that carries the drug in both conjugated and free forms. Melphalan is slowly released from G5-acetal-melphalan-DH/melphalan, with the conjugated melphalan released more quickly at pH 5.3 due to acid-triggered acetal bond cleavage. The formulation's …

Magnetic Separation Of Lunar Regolith Simulants With Applications To In Situ Resource Utilization On The Moon, Peter Bachle, Jeffrey Smith, Fateme Rezaei, David Bayless, William Schonberg, Daoru Han

Chemical and Biochemical Engineering Faculty Research & Creative Works

The development of in situ resource utilization (ISRU) for metal extraction is imperative as a steppingstone for habitation construction in lunar and non-terrestrial environments. Separation of minerals by chemical composition is important to optimize metal and oxygen liberation from lunar ore. To this effect, devices capable of separating aluminum bearing minerals from iron-bearing minerals from the lunar regolith simulants have been developed. Twenty-eight different simulants have been used in this study. A dual-belt separator was designed to reduce middling. Para-magnetic minerals were reliably separated using a neodymium N52-magnet-separator system. Effective separation of aluminum-bearing minerals from iron-bearing minerals was greater than …

Thermal Management Of Adsorption-Based Biogas Upgrading Systems Via Incorporation Of Phase-Change Materials, Kyle Newport, Khaled Baamran, Ali A. Rownaghi, Fateme Rezaei

Chemical and Biochemical Engineering Faculty Research & Creative Works

Thermal management of adsorption columns is necessary to maintain their effectiveness while reducing the energy requirements of the overall separation process. In this work, we aimed at investigating the suitability of blending adsorbents with phase-change materials (PCMs) to adjust the thermal profile of a biogas upgrading column. A commercially available PCM (Nextek 28D) in quantities of 10, 20, and 30 wt. % was blended with zeolite 13X in two configurations, namely, traditional pellets and 3D-printed monoliths. The use of different structures allows for better analysis of thermal profiles and assessment of the effectiveness of the PCM in a packed bed …

Transitioning To A Lower Global Warming Refrigerant, A Performance Study Of R-513a And Hfc-134a In Commercial Chillers, Hossein Abedsoltan, Mark B. Shiflett

Chemical and Biochemical Engineering Faculty Research & Creative Works

The performance of R-513A and HFC-134a refrigerants is compared in two identical chillers operating at the University of Kansas. R-513A is a more environmentally friendly refrigerant due to its lower global warming potential that can be used as a retrofit replacement for HFC-134a in chillers. This study investigates the performance comparison of transitioning from HFC-134a to R-513A. The chillers have been in operation for two years, and cooling capacity, coefficient of performance, and other operating parameters are compared under similar cooling conditions. Cooling capacities ranged from 100 to 500 kW for both chillers. Overall, the energy consumption and coefficient of …

Fit-For-Purpose Heavy-Duty Fishing Equipment Designed To Safely Retrieve A Damaged Wireline Cable From An Active, Sour Gas Well Located Offshore, M. N. Amri, R. Macaulay, S. Aboelnaga, A. Abouganem, M. Al Dahhan

Chemical and Biochemical Engineering Faculty Research & Creative Works

Wireline operations play a crucial role in the oil and gas industry, facilitating essential tasks like well maintenance, data collection, and intervention. These operations involve deploying substantial downhole tools and large cables into the wellbore, but this endeavor is not without its challenges. Particularly, when a wireline cable breaks downhole, it poses significant risks. Unplanned wireline breakages result in demanding heavy-duty fishing operations when they occur in challenging offshore environments and unfavorable downhole conditions. in this work, strategic planning and execution were applied in a complex e-line cable recovery in a live, sour gas well without the need for well …