Engineering Commons^™

An Overview Of Biomass-Derived Graphene Oxide And Its Characteristics For Future Sustainable Applications, Afif Wardana, Ahmad Nabil Shahab, Donanta Dhaneswara, Nofrijon Sofyan

Journal of Materials Exploration and Findings

The production of graphene oxide (GO) from biomass presents considerable promise as a sustainable alternative substitute for traditional semiconductors. Biomass waste, abundant and often underutilized worldwide, is distinguished by its high carbon content and regenerative characteristics, rendering it an optimal resource for sustainable material production. By heating its biopolymers, lignocellulosic biomass can be used as a new material to make graphene, which forms three-dimensional turbostratic crystallites. These crystallites, composed of partially defective aromatic carbon sheets with graphite-like characteristics, make it easier to create GO with specialized functions for cutting-edge applications. Its capability underscores the revolutionary potential of biomass waste in …

Morphological Test Of Areca Nut Fiber Ceramic Membrane Using Scanning Electron Microscopy Energy Dispersive X-Ray Mapping Spectroscopy, Amelia Marzain, Siti Umi Kalsum, Marhadi Marhadi, Ahmad Nabil Shahab

Journal of Materials Exploration and Findings

This study investigates the potential of ceramic membranes derived from areca nut fiber as a cost-effective and environmentally sustainable material for the removal of iron (Fe) and manganese (Mn) from groundwater. Two types of membranes were fabricated: one without activation and one chemically activated using 10% sodium hydroxide (NaOH). The morphological and elemental characteristics of both membranes were analyzed using Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray (EDX) mapping. The concentrations of Fe and Mn before and after treatment were measured using Atomic Absorption Spectroscopy (AAS). The NaOH-activated membrane exhibited a more porous surface structure and higher oxygen content, …

Computational Study Of Cavitation In An Inducer Pump, Jaylen Leonard

UNLV Theses, Dissertations, Professional Papers, and Capstones

Cavitation is ubiquitous in liquid-handling turbomachines. Cavitation bubbles form when the local pressure drops below a fluid’s vapor pressure, and their subsequent collapse causes implosions that generate shockwaves and microjets. These effects lead to fluid instability and structural damage to the blades and casing in turbomachines. This thesis investigates this cavitation phenomenon in turbomachines using Computational Fluid Dynamics (CFD). The cavitation model built in ANSYS Fluent® is first validated in a venturi tube model and then applied to an inducer pump. The geometry of the pump is derived from the Space Shuttle Main Engine (SSME) Low Pressure Oxidizer Pump (LPOP) …

Quantifying Biocrust Evaporation In Arid Lands By Combining Thermal Imaging And Lysimeter Measurements, Rebekah C. Magness

UNLV Theses, Dissertations, Professional Papers, and Capstones

Biological soil crusts (biocrusts) are miniature ecosystems of living organisms incorporated within the soil matrix and established in the topmost millimeters of the soil surface. Biocrust plays a critical role in the hydrologic processes in arid lands, yet the extent to which it increases or decreases evaporation remains unclear. To gain a better understanding of the impact of biocrust on evaporation compared to bare soil, I studied a cyanobacteria-dominated biocrust patch surrounded by bare soil atop a lysimeter in the Mojave Desert near Las Vegas, Nevada. Using high-resolution thermal imaging, and the known latent heat flux from the lysimeter, I …

Ankimedbench: Evaluating Hierarchical Medical Knowledge In Language Model Embeddings, Neel Patel

UNLV Theses, Dissertations, Professional Papers, and Capstones

Despite achieving over 90% accuracy on medical benchmarks, recent studies show physicians cannot effectively leverage language models to improve clinical reasoning. Current benchmarks test isolated factual recall, but clinical practice requires hierarchical navigation through diagnostic categories—starting broad and narrowing systematically from chest pain to cardiovascular pathology to myocardial infarction to specific STEMI types. Existing evaluations cannot measure whether models preserve this taxonomic structure essential for clinical reasoning.

We introduce AnkiMedBench, built from 16,512 medical flashcards used by students preparing for licensing exams. Cards are organized across six hierarchy levels spanning 16 broad medical specialties to 672 specific diseases and conditions. …

Quantum Sensing Of Magnetic And Thermal Fields Using Nitrogen-Vacancy Centers On Spoof Surface Plasmon Waveguides, Maxwell Stonham

UNLV Theses, Dissertations, Professional Papers, and Capstones

Nitrogen-vacancy (NV) centers in nanodiamonds are solid-state quantum defects capable of detecting magnetic fields and temperature at the nanoscale with high spatial resolution and optical addressability at room temperature. Their spin-dependent fluorescence enables optically detected magnetic resonance (ODMR), a technique widely used for quantum sensing. However, enhancing optical readout efficiency remains a critical challenge for scalable integration and various methods can be used to improve this.

This thesis explores a hybrid quantum sensing platform that integrates NV-based sensing with spoof surface plasmon waveguides designed to enhance optical excitation and emission efficiency through localized spoof plasmon modes supported by subwavelength corrugated …

Automated Spectrum Analysis And Radionuclide Identification For Robot-Based Gamma Probes, Kennedy Ochieng Mengoh Alila

UNLV Theses, Dissertations, Professional Papers, and Capstones

Gamma spectroscopy is a technique used for the detection and identification of nuclear materials. Gamma-ray emission by radio nuclides is detected using scintillation detectors or semiconductor detectors such as NaI and CZT. Robot-based gamma probes enable radiation measurements in large areas and hard-to-reach cluttered hazardous environments, which significantly reduces radiation risks to personnel. The robotic probes require automated on-board gamma spectrum analysis and capabilities with platforms (unmanned aerial vehicles and unmanned ground vehicle systems) which use Robot Operating System (ROS). The aim of this thesis was to develop a method of an automated spectral analysis and isotope identification for robot-based …

Application Of Adversarial Volumetric Cnns To 3d Face Generation Using Latent Space Gaussian Embeddings, Ali Raad Abdulkareem, Marwa Jabberi, Islem Jarraya, Tarek M. Hamdani, Khmaies Ouahada, Adel M. Alimi

Iraqi Journal for Computer Science and Mathematics

Although 3D face generation is extensively studied in computer vision, most existing methods prioritize reconstructing 3D geometry from available 2D or 3D inputs rather than generating novel faces directly from latent representations. To bridge this gap, we present the application of Adversarial Volumetric Convolutional Neural Networks (AVCNN), a tailored adaptation of the vanilla 3D Generative Adversarial Network (3D-GAN), to 3D face generation using latent space Gaussian embeddings. We first assemble a custom 3D facial dataset to provide the requisite facial characteristics and to ensure sufficient coverage of geometric variation across identities. The generator, implemented as a decoder, maps latent space …

Durability Of Alkali-Activated Concretes Under 5% Sulfuric Acid Environment, Celal Karabaş, Anıl Niş

Journal of Sustainable Construction Materials and Technologies

The investigation focused on the resistance to 5% sulfuric acid degradation of the alkali-activated concretes (AAC). The AAC was manufactured using a blended binder of 50% slag and 50% F-type fly ash. The AAC was activated using a blend of 14 M sodium hydroxide and sodium silicate, with a hydroxide-to-silicate ratio of 1/2,5. Six AAC were produced against a 5% sulfuric acid environment, varying the binder amounts (400–500–600 kg/m3) and activator-binder (A/B) ratios (0,45–0,55). The chemical resistance of AAC was evaluated by visual appearance, variation in weight and compressive strengths. The findings pointed out that more gypsum and higher weight …

Comprehensive Risk Assessment For Construction Site Managers In Kosovo: A Mixed-Method Approach, Muhamet Ahmeti, Besian Sinani

Journal of Sustainable Construction Materials and Technologies

This study developed and validated a hybrid ISO 31000:2018 Kosovo-compliant risk assessment framework tailored for construction site managers operating within transitional economies. The research employed audits of 20 ISO-certified contractors in Pristina, Kosovo, along with field observations, interviews, and quantitative risk matrices. The findings indicate a critical concentration of risk, with 70% of firms classified as "High" or “Very High” risk. The most prevalent hazards identified were working at height without collective protection, unprotected electrical systems, and manual handling of heavy materials. Regression analysis revealed that firms with a designated safety champion achieved significantly lower risk scores, whereas those with …

Behaviour Of Internally Strengthening Hollow Stainless-Steel Hot-Rolled Circular Columns Filled With Crumb Rubber And Recycled Aggregate Concrete, Wadhah M. Tawfeeq, Mohammed M. Rasheed, Mithaq Kohees, Ahmed W. Al Zandd, Saif Al-Balushi, Hamed Al Abdul Salam

Journal of Sustainable Construction Materials and Technologies

Stainless-steel sections are increasingly being utilised in favour of their higher durability. Simultaneously, the use of recycled materials in concrete is aligned with the global concern to encourage sustainable and environmentally friendly construction. The paper examined the behaviour of stainless-steel columns filled with concrete with crumb rubber (CR) and recycled aggregate (RA). It analysed the effect of different percentages of CR (0, 15, and 30) and RA (0, 15, and 50) on the compressive strength of the concrete and the performance of the columns using stainless-steel hollow sections. 20 specimens were manufactured, 18 of which were cast with concrete containing …

Retracted: Fuzzy Backstepping Approach To Stabilizing Fuzzy Parabolic Partial Differential Equations, Zainab John, Fadhel S. Fadhel, Samsul Ariffin Abdul Karim, Teh Yuan Ying

Iraqi Journal for Computer Science and Mathematics

In this work,\floatquery[-14pc]AU: Please provide ORCID ID for remaining authors. we study the solvability and stability of the fuzzy reaction-diffusion equation and the fuzzy diffusion equation with nonhomogeneous boundary conditions. Firstly, we derive the fuzzy exact solutions by converting the nonhomogeneous boundary condition to a homogeneous condition, then we prove the instability of the solution by using simulation approach with the help of Maple program. From this, we have decided to implement the fuzzy backstepping approach to developed the stabilization of the fuzzy parabolic partial differential equations. By using this approach together with the generalized Hukuhara (gH) derivative, we were …

Piezoelectric Concrete: A Smart Material Approach For Energy-Harvesting Structural Technologies, Dianah Mazlan, Vynotdni Rathinasamy, Naveen Kumar, Liu Chunpeng, Elango Elango

Journal of Sustainable Construction Materials and Technologies

The rapid growth of urban infrastructure demands innovative materials that not only support structural performance but also contribute to sustainability through energy harvesting. Piezoelectric concrete, which integrates ceramics, polymers, nanomaterials, and bio-based fillers into cementitious matrices, has emerged as a promising solution. This review systematically explores the fundamentals of piezoelectricity in concrete, highlighting how stress-induced electromechanical coupling enables both energy harvesting and structural health monitoring. The paper critically evaluates major material systems including PZT ceramics, PVDF polymers, hybrid nanocomposites, and emerging bio-based materials, alongside their integration strategies such as embedded and surface-mounted approaches. Applications across pavements, bridges, and smart buildings …

Empowering Wireless Mesh Uav Networks Through Software-Defined Networking, Hieu Quang

Electrical and Computer Engineering ETDs

Unmanned Aerial Vehicles (UAVs) have been widely deployed in applications such as environmental monitoring, disaster response, and surveillance. Effective coordination between UAVs depends on low-latency inter-UAV communication to exchange state information, decisions, and other critical data. UAV networks are inherently dynamic which necessitates a framework capable of handling scenarios such as traffic re-routing, and resilience to communication failures. To address the challenges of managing dynamic UAV networks, this thesis proposes a dual network approach composed of three main components. First, the Better Approach to Mobile Ad-hoc Networking (BATMAN) protocol is used to enable communication among UAVs. Second, the OpenFlow protocol …

A Bump Hunting Approach To Finding Interpretable Data Pockets, Tushar Ojha

Electrical and Computer Engineering ETDs

This dissertation approaches the problem of extracting simple interpretations from local regions of data. This is sometimes called bump hunting because the local regions of interest have a high concentration of a particular output value. This work develops a bump hunting method for discrete-valued tabular data where each bump is modeled by a rectangular region of the input data space so its rule-based description admits a simple logical interpretation that can inform decisions. This method is designed for labeled data where each input feature has a distinct meaning that may or may not be related to the output, and the …

Fedchae: Federated Learning With Client Clustering And Hybrid Adaptive Engagement, Chaeeun Park

Electrical and Computer Engineering ETDs

As machine learning adoption expands, data privacy concerns have grown significantly. Federated Learning (FL) addresses this challenge by allowing clients to train locally and share only their model parameters with the server. However, conventional FL methods such as FedAvg suffer from high communication overhead, as all clients must participate in every global round.

This paper proposes FedChae (Federated Learning with Client Clustering and Hybrid Adaptive Engagement) to balance communication efficiency and model accuracy. FedChae alternates between Grouping Rounds, where all clients perform clustering, and Conventional Rounds, where one client per cluster updates the model.

Simulations with 100 clients using Multi-class …

Emulation Of Orbital Dynamics And Control Of Fully Actuated Seven-Axis Prismatic Joint Systems, Bennett Russell

Electrical and Computer Engineering ETDs

This thesis details the system modeling, design, control, simulation, construction, and testing of a fully-actuated seven axis prismatic joint system created for the primary purpose of emulating on-orbit maintenance tasks. Additionally, it seeks to further research of space-based control schemas and investigate stiction as a case study with a mountable hybrid hinge system that emulates stiction. Controllers are evaluated under common limits and metrics, including time to escape, overshoot, mechanical work, and limit-exceedance counts. Comparisons span a PID baseline, deterministic MPC/MPPI, and a probabilistic POMDP policy. Results verify the emulator and hybrid hinge meet the intended design criteria and show …

Non-Destructive Characterization Of Ion Irradiated Yttrium Hydride For Microreactor Applications, Ryan E. Pena

Nuclear Engineering ETDs

As energy demands increase, nuclear reactors, especially microreactors, become a promising energy source. These reactors run at high temperatures (>280°C), requiring moderators that can endure these environments. Yttrium hydride is a possible moderator, but little is known about the material’s phase stability and hydrogen retention under irradiation. Through the use of a gold ion beam, samples with stoichiometries ranging from 1.6 to 2.0 were irradiated and tested. Through Vickers hardness testing, a model was created showing a correlation between hydrogen content and hardness. Raman spectroscopy showed high temperature and irradiated samples have significant hydrogen loss. XRD quantified this hydrogen …

Sequential Low Dose Proton Irradiation And Nanomechanical Testing To Understand Mechanical And Microstructural Property Changes In Alloy 709, Abhishek Kc

Nuclear Engineering ETDs

Alloy 709, a 20Cr25Ni alloy, is an advanced austenitic steel designed for next generation sodium fast reactors. Preliminary studies have shown the potential of Alloy 709 in sodium fast reactors. In this study, Precipitate Treated Alloy 709 specimens are irradiated with 2 MeV H⁺ at 500 °C from 0.0057 dpa to 1.7 dpa. Electron microscopy characterization techniques are used to understand the effects of radiation on mechanical properties as well as microstructure of Alloy 709. The microstructure did not show formation of voids, amorphization of precipitates, or increase in grain size up to 1.7 dpa. Correspondingly nano-indentation and micro-pillar …

Coupled Adjoint-Based Perturbation Theory For Dynamics And Heat Transfer Multiphysics For Nuclear Transients, Alexis Maldonado

Nuclear Engineering ETDs

Nuclear reactor multiphysics modeling and simulation (M&S) enable advanced reactor design by analyzing how systems will react over time to various configurations, scenarios, and perturbations. However, high-fidelity coupled transient M&S for reactor cores are computationally expensive, making robust analyses challenging. This work develops a Coupled Adjoint-based Perturbation Theory for dynAmIcs and heat traNsfer (CAPTAIN) framework to rapidly quantify the impact of uncertainty to overall transient responses by generating sensitivity coefficients for temperature, power, and delayed neutron precursor concentrations using forward and adjoint solutions. This work presents an initial proof of principle, verified with direct perturbations to several inputs. Furthermore, this …

A Risk-Informed Approach To Performing The Pre-Closure Safety Analysis For The Deep Borehole Disposal Of Radioactive Waste, Jennifer Elizabeth Leute

Nuclear Engineering ETDs

Deep borehole disposal is an emerging concept which involves disposing of radioactive

waste in boreholes several kilometers deep then backfilling to minimize radionuclide

transport and distribute weight. Unfortunately, little documentation exists on borehole

safety case development, especially for pre-closure operations. This study aims to close

this gap by proposing a graded approach matrix based on consequence, maturity, and

complexity. Two case studies are used to demonstrate this application: Hanford CsCl

capsules and spent PWR assemblies. Simulations are used to predict potential for dose

exposure, revealing CsCl capsules have a much higher potential for being above the 5

rem public dose …

Investigating The Fatigue Behavior Of Inconel 939 And Inconel 718 Through Micromechanical Testing, Mohammad Hossein Shahini

LSU Doctoral Dissertations

A detailed evaluation of fatigue crack growth (FCG) in a silicon-modified Inconel 939 alloy, fabricated via laser powder bed fusion additive manufacturing (L-PBF AM), was performed using cyclic bending tests on pre-notched microscale cantilevers with a cross-sectional dimension of 25 µm × 25 µm. To our knowledge, this study is the first to demonstrate that such microscale cantilever tests can effectively capture both the threshold and Paris-law regimes of FCG, despite the limited specimen size. The precise fabrication of these small-scale specimens allows for controlled fatigue crack propagation relative to the microstructure while minimizing the presence of volumetric defects. Notably, …

Design And Evaluation Of The Influence Of Mutual Induction On Microbial Electrolysis Cell Performance And Biogas Production, Ashley L. Blackwell

Civil Engineering ETDs

Microbial electrolysis cells (MECs) present a pathway for energy recovery in wastewater treatment by converting organic substrates into methane or hydrogen. Traditional MEC designs typically rely on physical electrode contacts and expensive materials, which restrict their scalability. This study introduces the first induction-based MEC that uses mutual inductance between an external copper wrap and an internal coil to generate a fluctuating electrical potential, removing the need for expensive electrodes. The induction-stimulated reactor showed faster total organic carbon removal and a higher CH4/CO2 ratio compared to a conventional anaerobic digester, indicating improved carbon-to-methane conversion, although total gas yield remained similar. Microbial …

Graph Based Planning With Guarantees, Trazon Tyrik Jimerson

Mechanical Engineering ETDs

This thesis presents two graph-based methods with formal guarantees for motion planning and routing. First, the invariant-set motion planner (ISMP), which uses constraint admissible positive invariant (CAPI) sets of closed-loop dynamics, is adapted for spacecraft attitude planning to avoid moving keep-out zones. Contributions include time bounds for maneuvers via exponential stability, a single-stage reachability graph from one-step backward reachable CAPI sets, and its multi-stage expansion to certify node safety over time. Simulations verify safe attitude control with moving obstacles. Second, we formulate a convex optimization problem over a network for evacuation planning with operational constraints such as helicopter capacity and …

Real-Time Frequency Tuning Of Kinetic Energy Harvesters Via System Mass Adjustment, Rahul Adhikari

Mechanical Engineering ETDs

This research presents a method for real-time frequency tuning of piezoelectric kinetic energy harvesters through system-mass adjustment. Custom 3D-printed proof masses with cavity arrays were used to redistribute solid or liquid mass, enabling controlled modification of resonant frequency. Experimental studies using microparticles and liquids—including water, silicone oil, and sodium polytungstate—demonstrated an achievable tuning range of 115.27 Hz with sub-hertz resolution (< 0.1 Hz), confirming precise and repeatable frequency control. Finite-element modeling guided design optimization, while a microfluidic channel system enabled automated liquid filling for real-time operation. A MATLAB-based EH_Tuning application was developed to visualize and predict frequency responses. The combined …

Design And Development Of Evacuated Photovoltaic-Thermal Systems For Efficient Cogeneration Of Heat And Electricity, Behnam Roshanzadeh

Mechanical Engineering ETDs

In conventional PV systems, most of the solar energy is dissipated into the environment as heat. Accordingly, hybrid Photovoltaic-thermal systems have been developed to utilize the waste heat from PV cells for various thermal applications. However, most PVT systems suffer from low thermal performance compared to solar thermal collectors, as the absorber plate in PVT systems is partially or fully covered by PV cells. This dissertation focuses on improving the thermal performance of PVT systems by introducing the evacuated PVT systems.

An evacuated-tube PVT system was designed and simulated for domestic hot water supply. The evacuated-tube PVT system demonstrated 40% …

Simulation Of Stress Induced By Laser Heating Of Glass, Austin Marsh Schuberth

Mechanical Engineering ETDs

The purpose of this work is to create a method for accurately simulating the stresses due to heating from femtosecond laser pulses. Our work aims to calculate stress and strain in glass exposed to laser pulses used for laser welding. We simulate the effects of thermal heating, thermal expansion, and the viscoelasticity of glass for a single straight weld bead. The laser heating of K9 borosilicate glass was simulated using Finite Element Analysis (FEA). Thermal models developed by other researchers in earlier work were utilized in calculating the temperatures due to the laser exposure to the glass material. 2D simulations …

Thermally Stable And Regenerable Catalysts For Alkane Dehydrogenation, Ryan Alcala

Chemical and Biological Engineering ETDs

Shale gas upgrading reactions have gained much interest since production dramatically increased around 2010. These reactions occur at high temperatures (600°C +) where undesired processes like sintering and/or coking often occur. It is of interest to use materials like ceria as a catalyst support in these alkane conversion reactions, but ceria is prone to losing active surface area through sintering. It is also of interest to understand the behavior of PtMn and PtZn intermetallics for propane dehydrogenation as they have been identified as some of the best catalysts by theory-based prediction in literature. This manuscript explores ways of utilizing ceria’s …

Application Of Bimetallic Transition Metal Oxides Electrocatalysts For Li-Co2 Batteries And Li-O2 Batteries, Jianda Wang

Chemical and Biological Engineering ETDs

Li-ion batteries are the dominant commercial rechargeable batteries nowadays, which are used in electronic devices and electrified transportation widely. However, undesirable energy density of Li-ion batteries prohibits them from meeting requirements of new generation electronic devices. Therefore, it is important to find more alternative electronic energy storage systems with higher capacity. Fortunately, Li-CO2 batteries, featured high capacity and ability to convert CO2, have become a promising candidate to replace Li-ion batteries. In addition, Li-O2 batteries also attract people’s attention due to their high energy density and low cost. However, Li-CO2 batteries and Li-O2 batteries both face challenges of terrible cycle …

Analysis Of Heat Transfer And Pressure Drops Associated With Twisted Tube Heat Exchangers, Braden Foderaro

Nuclear Engineering ETDs

Several studies have been done on the effects of twisted tubes in heat exchangers, including the correlations that relate the flow parameters to the heat transfer and pressure drop experienced. These studies are new, with the earliest being performed in 1982. As such, there are many correlations covering only certain flow parameters and geometrical configurations such as the Reynolds number and modified Froude number.

This thesis attempts to cover flow regimes and tube geometries not yet studied and yield correlations. Data are gathered from heat exchangers featuring twisted tubes with water as the working fluid. It is noticed that the …