Digital Commons Network^™

Temperature Dependent High Frequency Performance Of A 62% Algan Channel Hemt, Jiahao Chen, Abdullah Al Mamun Mazumder, Parthasarathy Seshadri, Dheekshinn Nandakumar, Ruixin Bai, Rafael Andrew Choudhury, M. Asif Khan, Chirag Gupta

Faculty Publications

This article reports on the temperature dependent performance of a HEMT with an Al_0.62Ga_0.38N channel layer and an Al_0.84Ga_0.16N barrier layer grown by metal–organic chemical vapor deposition. The device in this report was measured at room temperature and elevated temperatures of 100–150 °C. The sheet resistance increased from 3.5 kΩ/sq (25 °C) to 5.4 kΩ/sq (150 °C), while the contact resistance remained nominally similar. For a device with 160 nm gate length and 2 µm source-to-drain length, excellent electrical characteristics have been achieved when the device was operated at 150 °C with …

Novel Repurposing Of Empagliflozin-Loaded Buccal Composite (Chitosan/Silk Fibroin/Poly(Lactic Acid)) Nanofibers For Alzheimer’S Disease Management Via Modulation Of Aβ–Ager–P-Tau Pathway, Samar A. Salim

Nanotechnology Research Centre

Background/Objectives: Empagliflozin (EMPA) was repurposed for Alzheimer’s disease (AD) treatment via buccal delivery, exploiting novel nanofibers (NFs) integrating chitosan (Cs), silk fibroin (Fb), and poly(lactic acid) (PLA). Methods: EMPA-loaded Cs/Fb/PLA NFs were electrospun in different formulations to optimize the formulation parameters. The optimized formulation was then investigated for its enhanced in vivo effect. Results: Optimized nanofiber diameters ranged from 459 ± 173 to 668 ± 148 nm, possessing bead-free morphology confirmed by SEM and satisfactory mechanical properties. EMPA was successfully well-dispersed in the polymer matrix as evidenced by FTIR, XRD, and drug content. The optimized NFs displayed a hydrophilic surface …

A Suite Of Thermal Switches For Surviving Extreme Thermal Environments In Space, Matthew I. Ralphs, Matt Jensen, Alexis Eames, Matt Sinfield

Space Dynamics Laboratory Publications

Thermal switches are a key enabling technology for spacecraft operating in extreme thermal environments. Whether surviving the lunar night, managing intermittent high-power loads from deep space communication systems, or dealing with other extreme thermal environments, high-performance thermal switches allow critical missions to operate beyond conventional thermal design limits. This paper presents the development, testing, and performance of a suite of passive thermal switches designed for both spacecraft- and subsystem-level thermal control. The suite includes: (1) traditional in-line switch placed between sensitive components and radiators; (2) compact designs suitable for integration into standard bolted joint interfaces to modulate the conductance between …

An Investigation Of A Mach 15 Flow Over A Blunt Wedge Using First-Principles Potential Energy Surfaces: Influence Of Wall Temperature, Paolo Valentini, Zach Davis, Maninder S. Grover, Nicholas J. Bisek

Space Dynamics Laboratory Publications

The simulation of a Mach 15 air flow over a blunt wedge is conducted using the direct molecular simulation (DMS) method. Due to partial dissociation of the air mixture at the imposed free stream conditions, the shock layer contains N₂, O₂, NO, N, and O. All potential energy surfaces (PESs) used to model the various molecular interactions only describe electronic ground states energetics. Thus, no electronic excitation is modeled. An isothermal wall boundary condition is imposed, with full momentum and energy accommodation. Two wall temperatures are considered in this work, namely 1,000 K and 2,000 K. …

Hypersonic Non-Equilibrium Cfd And Dsmc Model Comparisons With The Varda Reentry Capsule, Jack D. Crespo, Paolo Valentini, Ashwin P. Rao, Zach S. Davis

Space Dynamics Laboratory Publications

Nonequilibrium aerothermodynamic modeling of the Varda hypersonic testbed capsule is conducted with direct simulation Monte Carlo (DSMC) and computational fluid dynamics (CFD) solvers. Flowfield properties at the 78 km reentry trajectory point are extracted to compute line of sight spectral radiance using two radiative emission codes, namely HARA and NEQAIR. Computed spectra are compared to spectral radiance measured by an in situ optical emission spectroscopy payload flown on Varda’s W-2 capsule in 2025. Model comparisons to the experimental data reveal discrepancies between the HARA and NEQAIR radiative emission predictions in both overall magnitude and qualitative behavior. NEQAIR was found to …

Simulation Results Of Spaceborne Ssa Using A Comprehensive Passive Radar Model, Chinmay Gaikwad, Filipe Senra, Thomas Alan Lovell, Hao Peng, Berker Pekoz, Tianyu Yang

Publications

In this paper, a high-fidelity simulation framework is developed to assess the feasibility of tracking space debris using a large low-Earth orbit (LEO) satellite constellation equipped with onboard passive radar sensors. By exploiting illumination from a distributed network of ground-based transmitters, the constellation provides consistent line-of-sight access to debris objects at higher altitudes, enabling angles-only detection and tracking. This approach yields a scalable, automated, and cost-effective architecture for next-generation space surveillance and contributes to more resilient space traffic management. A complete angles-only passive-radar orbit-determination pipeline is introduced and demonstrated. Initial orbital states are generated using a rate-aware constrained admissible-region multiple-hypothesis …

Combinatorial Synthesis Of Protein-Polymer Conjugates By Post-Polymerization Modification Of Poly(Pentafluorophenyl Acrylate)S, Emily W. Kish, Thatcher M. Lee, Alexis M. Ziemba, Ama Boamah, Bianca Figueroa, Margherita Piccardi, Carey E. Dougan, Sarah J. Moore, Maren E. Buck

Chemistry: Faculty Publications

Combinatorial methods for preparing polymeric biomaterials enable the rapid identification of materials useful for many applications in science, medicine, and engineering. In the work described here, we demonstrate that side-chain reactive polymers can be used as templates for the rapid preparation of a small library of diversely functionalized protein–polymer conjugates. The activated ester polymer poly(pentafluorophenyl acrylate) (PPFPA) was modified postpolymerization with substoichiometric equivalents of three hydrophilic primary amines to yield a library of amphiphilic, side-chain reactive copolymers. These copolymers were then conjugated to two receptor-targeting proteins, holotransferrin (hTF) and an engineered fibronectin-based protein (Fn3), through amine-activated ester coupling. We investigated …

Optimized Resnet-18 Architecture For Multi-Class Oral Diseases Classification, Ahmed Ahmed

Karbala International Journal of Modern Science

In recent years, the classification of oral diseases has gained significant attention due to its influence on public health and the necessity for early and accurate diagnosis. Traditional diagnosis depends on manual clinical assessment, which can be slow and subjective. An optimized and subsequently quantized model is required to provide a faster and more consistent diagnostic support tool. This paper proposes an optimized ResNet-18 architecture for the classification of six oral diseases. The optimization process is based on removing the Rectified Linear Unit (ReLU), Batch Normalization (BN), and convolutional layers from the base ResNet-18 blocks that contain 128 filters. This …

Cs Tools - Stormwater Management Software (Version 6.5.0), Donald V. Chase

Drainage Design Tools

The CS Tools program is an outgrowth of research conducted by the University of Dayton for CON/SPAN Bridge Systems.

Large-Scale Cubesat Chassis, Matthew D. Evans, Robert A. Bettinger

AFIT Patents

The present invention relates to large-scale CubeSat chassis and methods of making and using same. The disclosed CubeSat comprises specific structural features that can yield up to at least a 27 U CubeSat that has comparable or even better performance and benefits than that of smaller CubeSats. Such volume increase coupled with the structural integrity of Applicants' CubeSats opens up a wide range of CubeSat performance increases including, but not limited to, larger payloads, more diverse payloads and larger CubeSat fuel capacities. Such increased payload capabilities includes, for example, increased focal length capabilities and such improved maneuverability results in, for …

Optimal Placement Of Electric Vehicle Chargers: A Mixed-Integer Linear Programming Model, Joubin Zahiri Khameneh, Emmanuel Fagbenle

Faculty Publications

Electric vehicle adoption is growing, but New Hampshire lags in public charging infrastructure, especially in rural areas. This gap increases range anxiety and economic inefficiencies. In this study, we developed a mixed-integer linear programming (MILP) model to optimally locate new electric vehicle chargers statewide, maximizing coverage and equity under budget constraints. The model includes geographic coverage requirements, population-weighted equity, capacity limits, and a $28 million budget. Moreover, the model recommends 855 Level 2 chargers and 149 Direct Current Fast Chargers (DCFCs) across 247 ZIP Codes, nearly doubling public charging capacity and achieving 98.8% coverage within defined service radii. The plan …

Preliminary Evaluation Of Remote Sensing Evapotranspiration Models For Field-Scale Agricultural Water Management In Arid Central Iran, Somayeh Sima, Iman Raissi Dehkordi, Mohammadhosein Taghikhani, Neamat Karimi

Civil and Environmental Engineering Faculty Publications

Accurate estimation of actual evapotranspiration (ET_a) is crucial for effective water resource management and optimizing agricultural yields. While satellite-based surface energy balance ET_a models are widely adopted, their field-scale accuracy in under-researched regions, such as Iran, remains a critical knowledge gap. This study assesses five prominent models—PySEBAL, PyMETRIC, SSEBop, PyTSEB, and ETLook (from FAO’s WaPOR v.2, L1 product)—for daily ET_a estimation over an alfalfa field in the arid central part of Iran. Models were adjusted for the field using in situ weather data and Landsat-8 images, and validated against the scintillometer data. Results showed SSEBop provided …

Merging Terrestrial And Satellite Gravity Data For Africa: A Possibility To Fill-In The Data Gaps, Hussein A. Abd-Elmotaal, Norbert Kuhtreiber

Mansoura Engineering Journal

The major challenge that the IAG Sub-Commission on gravity and geoid in Africa faces is the significantly large gravity data gaps. It is essential to properly tackle this issue for all geodetic applications in Africa due to the large interpolation errors occur at these large gaps. Simple interpolation (using any type of interpolation technique) of the gravity data does not add new information at the large data gaps, and the solution is free there. Global Earth gravity models offer themselves as a possible way to fill-in such large data gaps, provided that they approximate the African gravity field to an …

Model-Based Investigation Of The Influence Of Environmental Conditions On The Energy Supply Of Multirotor Uavs, Morten Roßberg, Hanna Dibbern, Claudia Werner

Journal of Aviation Technology and Engineering

Flight time of unmanned aerial vehicles (UAVs) is limited by available energy, which is affected by the mission profile and external factors, such as environmental conditions. Two main environmental conditions that need to be considered are the impact of wind and ambient temperature on the UAV and its energy supply. The purpose of this study is to examine the effects of wind and ambient temperature to conduct a preliminary evaluation of flight performance and flight limitations. For this reason, three locations in the United States—New York City, Miami, and Fairbanks—are selected and the impact of the considered environmental conditions of …

A Contextual Attention-Based Transformer Model For Enhanced Hate Speech Detection On Twitter, Mira Mansour, Nancy Akoum, Seifedine Kadry

Iraqi Journal for Computer Science and Mathematics

Hate speech on social media poses significant societal challenges, necessitating accurate and context-sensitive automated detection. Traditional machine learning (ML) models typically rely on lexical or superficial features, limiting their ability to capture nuanced or contextually ambiguous expressions of hate speech. Recent transformer-based methods (e.g., RoBERTa) provide improved contextual understanding but often lack explicit mechanisms guiding the model’s attention to critical semantic tokens, thereby reducing interpretability and sensitivity to nuanced linguistic contexts. This paper introduces a novel contextual attention-guided transformer model that explicitly incorporates lexicon-guided attention supervision into RoBERTa fine-tuning, significantly enhancing semantic precision in hate speech detection on Twitter. Evaluations …

Research Progress On Generating Perfect Vortex Beams Based On Metasurfaces, Xiujuan Liu, Manna Gu, Ying Tian, Mingfeng Zheng, Bo Fang, Zhi Hong, Chee Leong Tan, Xufeng Jing

Electrical and Computer Engineering Faculty Publications and Presentations

This article reviews the latest advances in the generation and control of perfect vector beams using metasurfaces. In recent years, metasurfaces have garnered increasing interest due to their simple fabrication and easy integration. Perfect vortex beams (PVBs), as a type of vector beams, exhibit complex polarization states that require the superposition of multiple phases for their generation. The use of metasurfaces provides a compact platform for the generation of perfect vortex beams and enables more complex vortex beam control tasks, which are quite challenging for traditional optics. This paper begins by introducing the principle of perfect vortex beam generation using …

Finite Element Analysis Of Tire–Pavement Interaction Effects On Noise Reduction In Porous Asphalt Pavements, Miao Yu, Geyun Lv, Anqi Li, Jing Yang, Zhexi Zhang, Dongzhao Jin, Rong Zhang, Jiqing Li

Michigan Tech Publications

This study investigated the noise reduction performance of porous asphalt concrete (PAC) pavement under tire–pavement coupling conditions, addressing the limitations of field measurements and laboratory testing. First, tire excitation amplitude parameters were determined based on vibrational contact operational scenarios. Then, finite element simulations were conducted to systematically analyzing the tire–pavement coupling noise characteristics of PAC pavement. The results indicate that PAC pavement effectively reduces the air pumping noise due to its highly porous internal structure, leading to significant noise attenuation. Furthermore, the study examined the key factors influencing the tire–pavement coupling noise in PAC pavement. When maintaining constant vehicle parameters …

Numerical Solution Of A Coupled Nonlinear Dynamic Problem Of Thermoviscoelasticity, Abdali Abdukarimov, Ibodat Turabekovna Khaldybaeva, Askarova Shamshetdinovna Ayjamal

Technical science and innovation

This paper presents a numerical solution of a coupled nonlinear dynamic problem of thermoviscoelasticity. A Duffing-type oscillator with temperature-dependent properties is used to model nonlinear hereditary deformable systems. After specifying the temperature dependences of the elastic modulus 𝐸 and viscosity parameter 𝜂 and introducing dimensionless variables, the problem is reduced to a system of nonlinear integro-differential equations. A numerical procedure for solving this system is developed, and representative examples are computed. The results are presented in graphical form for various values of the governing parameters.

Precision Acoustofluidics For High-Throughput Mechanobiology In Suspension Cells, Kaichun Yang, Ruoyu Zhong, Ke Li, John Mai, Pengzhan Liu, Ye He, Joseph Rich, Ying Chen, Janna Wang, Zhiteng Ma, Zhiteng Ma, Xianchen Xu, Qian Wu, Tony Jun Huang

Faculty Publications

Mechanomodulation, the process of altering cellular behavior through applied mechanical forces, plays a critical role in physiological processes and has substantial implications for cancer therapy, immunology, and drug development. However, precise and efficient stimulation of nonadherent cells remains a major challenge, limiting the investigation of mechanotransduction pathways and the development of targeted therapeutics. Here, we developed an acoustofluidic platform named Suspension-cell Targeted Response to Excitation via Acoustofluidic Mechanomodulation (STREAM) to enable precise, high-throughput stimulation of suspension cells. STREAM accomplishes this using 101.14-megahertz high-frequency surface acoustic waves to deliver controlled mechanical stimulation at a throughput of 500,000 cells per minute. STREAM …

Pengujian High Fidelity Prototipe Media Pembelajaran Interaktif Bahasa Inggris Dengan Gamifikasi Menggunakan User Experience Questionare, Adhitya Prastyadi, Meizano Muhammad Ardhi, Daniel Rinaldi, Margaretha Karolina Sagala

Jurnal Sosial Humaniora Terapan

Abstract

Testing a Hi-Fi Prototype of Interactive English Learning Media with Gamification Using UEQ

This study aims to test and evaluate the User Experience (UX) quality of a High-Fidelity prototype for interactive English learning media integrating gamification elements. The research is motivated by the low English proficiency and motivation among Indonesian students, and the potential of digital media and gamification to enhance learning engagement. Inspired by the success of the Duolingo application, this prototype was designed to create an enjoyable and effective learning experience. A quantitative research methodology was employed, involving high school students as participants selected via purposive sampling. …

Exploring The Role Of Occupational Therapy In The Delivery Of Trauma-Informed Services To Hospital-Based Clients Ot, Frank Czuba

Journal of Applied Disciplines

Hospitalization can traumatize clients and impact overall health outcomes, leading to increased hospital readmission rates and resulting in a negative impact for both clients and providers. Limited information exists regarding how hospital-based occupational therapists evaluate and address trauma, even though incorporating trauma-informed principles into professional practice can enhance the occupational therapy process. The study explored the comprehension and perceived significance of trauma-informed tenets among occupational therapists delivering services in hospital-based settings. A quantitative research study with an exploratory design was implemented to explore how occupational therapists (OT) understand and utilize trauma-informed practices with their clients in a hospital setting. An …

The Impact Of Natural Cavities On Mining Feasibility In Brazil: Dilemma Between The Sustainability Of Mining Operations And The Environment, Tiago Leite, Felipe Souza, Mariana Silva, Iuri Brandi, Hernani De Lima

Journal of Sustainable Mining

Due to the legislation on natural underground cavities in Brazil, mineral reserves have been blocked, causing a great dilemma between the sustainability of the mineral activity and the preservation of cavities. This study presented an analysis of the evolution of the federal cave legislation, pointing out the main gains and contribution to the theme, in which the importance in the Brazilian scenario of the publication in 2017 of Normative Instruction N° 01, which updated the procedures for the definition of these “other forms of compensation” to the irreversible negative impact on cavities with a high degree of relevance. In this …

Multivariate Stochastic Mine Scheduling Targeting Stationary Grades Considering Risk Uncertainty And Hierarchical Variables, Augusto A. T. Toledo, Joao F. C. L. Costa, Diego M. Marques, Luciano N. Capponi

Journal of Sustainable Mining

In short-term mine planning for deposits characterized by multiple variables, sequential diglines are generated with an emphasis on maintaining consistent grade distributions across mining periods. This research integrates an array of mineral variables, including deleterious elements, to facilitate the establishment of excavation geometries that enable precise grade and volume control within operational production zones. Through the systematic application of geostatistical analysis coupled with process optimization, geological risks associated with grade uncertainties are minimized, and an optimized operational sequence for the extraction of mineral blocks is pursued. The main point of this approach is maintaining grade distributions aligned with the historical …

An Innovative Implicit Modeling Technique To 3d Deposit Modeling: A Case Study Of The Chromite Mine, Ali Can Ozdemir Ozdemir, Yavuz Tore

Journal of Sustainable Mining

The location of an orebody known to show regional variability in space is determined only through 3D geological modeling. A reliable 3D orebody model must be obtained to ensure resource efficiency and sustainability in the mining industry. In addition, 3D geological modeling has become indispensable in intelligent mining, smart mining, and mining 4.0. In previous years, explicit methods were widely used for 3D geological modeling. However, the validity of geological models produced with these methods has been debated. It has been understood that they are inadequate in modeling vein-type mineralizations with complex geometry in particular. For this reason, implicit modeling …

A Review Study Of The Relationship Between Coal Fly Ash Characteristics And The Presence Of Rare Earth Metals From Steam Power Plants In Indonesia, Muhammad F. Shafiyurrahman, Shofa Rijalul Haq, Nurkhamim Nurkhamim, Ade Kurniawan, Rofa D Bulopa, Rizki Khoiriah Nasution

Journal of Sustainable Mining

The establishment of a coal mining downstream ecosystem focused on a sustainable and environmentally friendly economy is an important goal for many countries. One strategic step in achieving this goal is the utilization of coal fly ash (CFA) waste as a secondary source of rare earth elements (REE). The use of CFA provides a solution to the environmental and health challenges resulting from mining primary sources. Prior to developing REE extraction technology, CFA characterization must be conducted. Therefore, this study addresses the relationship between CFA characteristics and the presence of REE. Based on the ASTM C618-12 standard, CFA in Indonesia …

Integrated Optimization Of Underground Mine Ventilation Using Hardy Cross, Monte Carlo Simulations, And Machine Learning Techniques: A Step Toward Sustainable Mining, Hussein A. Saleem

Journal of Sustainable Mining

Underground mine ventilation is crucial for ensuring worker safety, air quality, and operational efficiency. Effective optimization of ventilation systems reduces energy consumption, enhances airflow distribution, and minimizes risks associated with harmful gases and fire hazards. This study proposed an integrated framework combining the Hardy Cross (HC) method, Monte Carlo (MC) simulations, and machine learning (ML) techniques to optimize the ventilation system at the Jabal Sayid mine in Saudi Arabia. The HC method was employed to provide deterministic baseline airflow calculations, while the MC simulations accounted for uncertainties in resistance values and environmental conditions, generating probabilistic distributions of key parameters. Among …

Study On Visualization Simulation And System Dynamic Optimization Of The Ore Drawing Process In Mine Chutes, Liang Juan, Zhu Quanjie, Hao Yingnan, Quan Zhongxue, Zhang Zhiwu, Liu Xiaohuic, Ouyang Zhihua

Journal of Sustainable Mining

The ore release process in metal mine chutes is a critical part of the mining operation. Based on the urgent demand for intelligent mining construction, this paper proposes a visualization simulation and dynamic optimization method for the mine chute ore release process using the open-source programs Python and Blender. The main research content includes: designing the simulation method and model for the ore release process, including the main control program, process subprograms, etc.; proposing a visualization simulation method for the mine chute ore release process based on Blender, studying the impact of ore shape and size on ore release efficiency, …

Assessment Of Heavy Metal Contamination In Surface Water Near Tailings Dam, Gera Techane Mengistu, Tesema Kebede, Enatfenta Melaku, Engdasew Temere

Journal of Sustainable Mining

Elevated levels of heavy metals in surface water can lead to the degradation of water quality, especially in mining areas where tailing dams are sources of heavy metal pollution. This study focuses on evaluating the concentrations of heavy metals in surface water near the Legadembi tailings dams. The mean concentrations (in µg/L) of various heavy metals including: arsenic (As), cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), mercury (Hg), molybdenum (Mo), nickel (Ni), lead (Pb), antimony (Sb), selenium (Se), thallium (Tl), uranium (U), vanadium (V), tungsten (W), zinc (Zn), and zirconium (Zr) were determined: 79.7, 0.15, 162.3, 0.66, 18.1, 0.01, …

Intrinsically Safe Pneumatic Seismic Source For Controlled Rock Mass ,Monitoring And Imaging In Underground Mining, Przemysław Sierodzki, Leszek Remiorz, Mateusz Ćwiękała, Krzysztof Krawiec

Journal of Sustainable Mining

This article explores the technical principles of pneumatic seismic sources, focusing on their application in underground mining operations, including environments prone to fire hazards. It introduces an intrinsically safe pneumatic seismic source as a cost-effective solution for quasi-continuous seismic excitation, useful for detecting stress concentrations in mining settings. These stress concentrations are identified through anomalies in seismic wave velocity, which may indicate potentially hazardous deformations in the rock mass. The developed system enables fully remote operation from the surface and integrates with a seismic monitoring system to capture high-resolution waveforms. The study provides an overview of the pneumatic system’s technical …

Investigating Frozen Paste Surface Disposal As A Climate Change Adaptation Strategy: Case Study Of Mont-Wright Mine, Khalil Hashem, Agus P. Sasmito, Laxmi Sushama, Ferri Hassani, Mehrdad Kermani

Journal of Sustainable Mining

The mining industry faces evolving challenges in adapting to the impacts of climate change. Among these challenges is the management of tailings. This study focuses on investigating surface disposal of non-cemented paste tailings, particularly the effect of water content, freeze-thaw cycles (FTC, defined as freezing the sample to –20°C and thawing it to +20°C), and ambient temperature on the mechanical characteristics and thermophysical properties of paste tailings. The potential for maintaining non-cemented tailings in a frozen state year-round is also investigated through field-scale numerical simulations. Experiment results of thermophysical properties of tailings with water content, freeze-thaw cycles and ambient temperatures …