Engineering Commons^™

Ventilation And Recirculation Airway Design For An Autonomous, Climate Controlled, Hydroponic Demonstration Unit, Nicholas Cross

Biological and Agricultural Engineering Undergraduate Honors Theses

For this Honors Thesis project, I designed and fabricated a ventilation and recirculation airway sub-system prototype for a hydroponic demonstration unit to be used as an educational demonstration for prospective students, illustrating the capabilities of biological engineers. This thesis focuses on the design of an autonomous air system that toggles between ventilation and recirculation modes based upon sensor output. In the literature review I discuss how ventilation can be used to achieve a targeted climate, the benefits of hands-on projects for education, and the optimum parameters for growing herbs in a hydroponic system.

In the design and fabrication process, every …

Defect Evolution In High-Temperature Irradiated Nuclear Graphite, Steve Johns

Boise State University Theses and Dissertations

Graphite has historically been used as a moderator material in nuclear reactor designs dating back to the first man-made nuclear reactor to achieve criticality (Chicago Pile 1) in 1942. Additionally, graphite is a candidate material for use in the future envisioned next-generation nuclear reactors (Gen IV); specifically, the molten-salt-cooled (MSR) and very-high-temperature reactor (VHTR) concepts. Gen IV reactor concepts will introduce material challenges as temperature regimes and reactor lifetimes are anticipated to far exceed those of earlier reactors. Irradiation-induced defect evolution is a fundamental response in nuclear graphite subjected to irradiation. These defects directly influence the many property changes of …

Direct Solar Absorption Nanoparticle Doped Membranes For A Hybrid Membrane Distillation And Photovoltaic Cell, Alejandro Espejo Sanchez

Boise State University Theses and Dissertations

The growing demand for clean water supplies is driving the need for an innovative approach of water desalination. Developing a method for treating water with high salinities is possible with membrane distillation (MD). Additionally, MD is very attractive for pairing with solar energy due to the low temperature requirements. The integration of a membrane distillation system with a photovoltaic (PV) system will result in the co-production of electricity and clean water, thereby improving the economics of MD. Such a hybrid system will directly absorb thermal energy in the membrane for desalination while taking advantage of the spectrally selective nature of …

In Vitro Method To Quantify And Visualize Volumetric Wear In Meniscus Subjected To Joint Loading Using A 3d Optical Scanner, Kate J. Benfield

Boise State University Theses and Dissertations

The menisci are fibrocartilaginous soft tissues that act to absorb and distribute load across the surface of the knee joint. As a result of mechanical wear and large repetitive loading, meniscus tissue can begin to breakdown, or degenerate. Meniscus degeneration increases the risk of tearing, weakened tissue integrity, and the progression of osteoarthritis. Therefore, it is imperative to understand the wear behavior of whole human meniscus to identify conditions that may significantly increase the risk of degeneration.

The objective of this study is to develop and validate an in vitro methodology for characterizing volumetric wear behavior in whole human meniscus …

Current-Mode Photon-Counting Circuit With Sige Bicmos Input Stage, Gonzalo Guadalupe Arteaga

UNLV Theses, Dissertations, Professional Papers, and Capstones

Continued advances in photodetector technology have helped improve the imaging capabilities of LiDAR systems or other time-of-flight imaging efforts. As a major part of the receiver within a LiDAR system, the photodetector can offer features such as faster rise times, narrower pulse widths, or larger gains to help achieve greater timing resolution or sensitivity to faint light levels. These benefits, however, are contingent on the ability of the accompanying readout circuit to reliably process the fast, electrical signals generated by the photodetector. While common front-end circuits involve the use of feedback amplifiers, their stability can become a major concern at …

Validation Of Novel Obstructive Sleep Apnea Treatment With Silicone Gel Experimental Models, Dustin Walter Burd

UNLV Theses, Dissertations, Professional Papers, and Capstones

Predictive modeling to increase treatment success rates for surgical procedures is becoming more common in the scientific community. For obstructive sleep apnea (OSA), modeling has been predominately performed using computers as opposed to experimental models. Computer simulation saves time by eliminating the need to fabricate complex experimental models but comes at the expense of insight gained through physical observations made in real time. Experimental models for studying OSA are needed to validate computational work, provide perspective on anatomical scale and demonstrate complex deformations in real time. This work addresses prior hurdles in experimental model fabrication with a novel process using …

Fast Neutron Assay Of Elemental Content Of Bulk Samples, Calder Emerson Lane

UNLV Theses, Dissertations, Professional Papers, and Capstones

The purpose of this research was to analyze the capabilities of fast neutrons in the detection and analysis of various isotopes in bulk samples. The deuterium-tritium (DT) fusion reaction generates highly penetrating, high-energy (14.1-MeV) neutrons which induce nuclear reactions in irradiated targets. Neutrons and gamma rays are generated in these reactions. Emitted gamma rays are characteristic of the emitter; the gamma spectrum enables stoichiometric identification of the assayed samples. Neutron backscattering can also be used for identification of the elemental composition of the sample.

This work had three objectives. The first objective was to develop a computational technique to model …

A Circle Hough Transform Implementation Using High-Level Synthesis, Carlos Lemus

UNLV Theses, Dissertations, Professional Papers, and Capstones

Circle Hough Transform (CHT) has found applications in biometrics, robotics, and imageanalysis. In this work, the focus is the development of a Field Programmable Gate Array (FPGA) based accelerator that performs a series of procedures and results in circle detection. The design is performed using Vivado High-Level Synthesis (HLS) tools and targeted for a Zynq UltraScale+ ZCU106. The implementation includes the following procedures: Gaussian filter, Sobel edge operator, thresholding, and finally the CHT algorithm. The performance is evaluated based on the execution time as compared to the software (Python code) execution and the analysis tools provided by Vivado HLS tool. …

Minimizing Visual Defects Through Augmentation Of Computer Aided Diamond Rough Planning, Abhijith Prabhu

UNLV Theses, Dissertations, Professional Papers, and Capstones

Many computer aided design systems today utilize a workflow where physically accurate rendering of the product is not a functional component of its design process. This gap in workflow can lead to a sub optimal product or even a longer iterative design process in instances where a product's visual attributes and aesthetics are one their primary functional characteristic.

Diamonds are graded on their carat, color, clarity and cut, referred to as the 4Cs of a diamond; a standard set by G.I.A. and universally agreed upon. The cut of a diamond significantly affects the rest of the characteristics as it modifies …

Alternate Novel Thermal Structure Interaction Designs Of Molten Salt Shell Structures At High Temperatures Ranging From 565˚C To 700˚C, Nathan David Tyrrell Loyd

UNLV Theses, Dissertations, Professional Papers, and Capstones

Excess energy from solar power stations and other baseline power production methods canbe stored in molten salts (MS) in the 565°C range, therefore allowing the use of large containers to store energy for up to a week and generate eight hours of electricity or more to be used during peak demand hours, at night, or adverse weather conditions, depending on the container size. Supported by Office of Naval Research (ONR), this research presents a survey of molten salt properties used in solar power storage, as well as the history of molten salt usage for energy storage and production for nuclear …

A Multi-Channel Mcp-Pmt Based Readout Integrated Circuit For Lidar Applications, Sachin Purushothaman Namboodiri

UNLV Theses, Dissertations, Professional Papers, and Capstones

Photon counting techniques are becoming more critical in fields such as LiDAR, high energy physics (HEP), and positron emission tomography (PET). For space-based aerosol-cloud-ocean (ACO) LiDAR, the total aggregate photon flux signal has a very high dynamic range, from a single-photon up to giga-photons per second for a single channel. This dissertation focuses on the design of a multichannel, photon counting readout circuit that can interface with MCP-PMTs for high dynamic range, space-based LiDAR applications. Chapter 2 presents the conventional current mode approach that has been employed to realize a photon counting circuit. A transimpedance amplifier, a 6-bit delay line …

Design And Fabrication Of A 6-Bit Current-Mode Adc For Lidar And High-Speed Applications, Jason Silic

UNLV Theses, Dissertations, Professional Papers, and Capstones

The design, simulation, fabrication, and testing of a 6-bit current-mode ADC is presented with related calculations. Capable of producing samples at greater than 100MHz, the proposed design should excel at measuring fast current transients such as those produced by arrays of avalanche photodiodes (APDs). An array of 63 current comparators feed digital logic gates, via “thermometer code,” that produce a 6-bit output word that is driven off-chip by appropriate buffers.The circuit was designed using Cadence Virtuoso design software. Simulated Differential Non-Linearity (DNL), with an 8µA reference current, is 1.656 LSB at the worst transition involving a scale change. Excluding scale …

Developments Of Machine Learning Potentials For Atomistic Simulations, Howard Yanxon

UNLV Theses, Dissertations, Professional Papers, and Capstones

Atomistic modeling methods such as molecular dynamics play important roles in investigating time-dependent physical and chemical processes at the microscopic level. In the simulations, energy and forces, sometimes including stress tensor, need to be recalculated iteratively as the atomic configuration evolves. Consequently, atomistic simulations crucially depend on the accuracy of the underlying potential energy surface. Modern quantum mechanical modeling based on density functional theory can consistently generate an accurate description of the potential energy surface. In most cases, molecular dynamics simulations based on density functional theory suffer from highly demanding computational costs. On the other hand, atomistic simulations based on …

Towards Sensorimotor Coupling Of A Spiking Neural Network And Deep Reinforcement Learning For Robotics Application, Kashu Yamazaki

Mechanical Engineering Undergraduate Honors Theses

Deep reinforcement learning augments the reinforcement learning framework and utilizes the powerful representation of deep neural networks. Recent works have demonstrated the great achievements of deep reinforcement learning in various domains including finance,medicine, healthcare, video games, robotics and computer vision.Deep neural network was started with multi-layer perceptron (1stgeneration) and developed to deep neural networks (2ndgeneration)and it is moving forward to spiking neural networks which are knownas3rdgeneration of neural networks. Spiking neural networks aim to bridge the gap between neuroscience and machine learning, using biologically-realistic models of neurons to carry out computation. In this thesis, we first provide a comprehensive review …

Emocolor : Fine-Grained Emotion Recognition From Skin Color Information, Maria Guadalupe Jimenez Velasco

Open Access Theses & Dissertations

In everyday human-to-human communication, emotions play a fundamental role. Emotions represent the affective behavior of humans that is multi-modal, subtle, and complex. Previous approaches based on conventional computer vision explicitly used shape information. Modern approaches based on deep learning implicitly exploit all information available in the image, but by their nature make it difficult to assess the contributions of each source of information. In addition, skin color as a unimodal technique to recognize emotions has been explored to recognize only three coarse-grained emotions in valence space.To the best of our knowledge, this work presents the first approach to fine-grained emotion …

An Analysis Of Wildlife Strikes To Aircraft In Brazil: 2011-2018, Flavio A. C. Mendonca, Julius Keller, Chenyu Huang Ph.D.

Publications

Purpose: Aircraft accidents due to wildlife hazards have become a growing safety and economic problem to the Brazilian and international aviation industries. These safety occurrences have resulted in significant direct and indirect economic losses as well injuries and fatalities worldwide. The purpose of this study was to develop empirical information obtained from the analysis of wildlife strike and aircraft operations data in Brazil that could be used for accident prevention efforts.

Design/methodology: The research team collected and analyzed aircraft operations as well as wildlife strike data from the 32 busiest commercial airports in Brazil, from 2011 through 2018. …

Polyrad -- Protection Against Free Radical Damage, Hannah Kim, Yin Tse, Andrew Webb, Ethan Mudd, Muhammad Raisul Abedin, Melanie R. Mormile, Subhadeep Dutta, Kaushal Rege, Sutapa Barua

Biological Sciences Faculty Research & Creative Works

The effects of elevated levels of radiation contribute to the instability of pharmaceutical formulations in space compared to those on earth. Existing technologies are ineffective at maintaining the therapeutic efficacies of drugs in space. Thus, there is an urgent need to develop novel space-hardy formulations for preserving the stability and efficacy of drug formulations. This work aims to develop a novel approach for the protection of space pharmaceutical drug molecules from the radiation-induced damage to help extend or at least preserve their structural integrity and potency. To achieve this, free radical scavenging antioxidant, Trolox was conjugated on the surface of …

Deepsea Coral Sample Container, Sara Passantino, Andrew Noble, Casey Smith, Thomas Smith

Mechanical Engineering

In order to better understand the health of our oceans and the species that inhabit them, scientists often collect samples for later analysis onshore. The demanding deep-sea environment makes this collection process a challenging engineering task. Samples must first be located, then removed from the seafloor and stored for transportation to the surface. The performance of the engineered solutions that complete each of these tasks is critical in allowing marine scientists to maximize the insight obtained from their expeditions. Marine Applied Research and Exploration (MARE) is an organization that performs such collection of organisms with the help of remotely operated …

Use Of Time-Domain Reflectometry To Characterize Thermal And Hydraulic Properties Of Unsaturated Sands, Xuelin Wang

Civil Engineering Dissertations - Archive

Unsaturated soil is an essential consideration for many geotechnical engineering fields, for example, soil bearing capacity, soil lateral earth pressure, slope stability analysis, and seepage-related problems. Thermal-hydro-mechanical (THM) processes govern the behavior of unsaturated soils. Therefore, it is critical to simultaneously measure soil moisture, density, and thermal properties to better study THM processes. A thermo-time-domain reflectometry (thermo-TDR) sensor, a dual-probe for both soil moisture and thermal properties, is improved (based on its previous design) and fully calibrated through various soils at different soil moisture circumstances. Nine different chemical reagents with known dielectric constant were utilized to perform calibration of the …

Evaluation Of The Use Of Anchorage Systems For Strengthening Concrete Members Reinforced By Fiber-Reinforced-Polymer (Frp) Laminate, Mai Abd Alrhman Alrhman Aljaberi

Civil Engineering Dissertations - Archive

An anchorage system is the most effective method for preventing or delaying the debonding of fiber-reinforced polymer laminates; however, despite extensive studies, the related design information is still unclear and limits its use. The goal of this research, therefore, is to investigate the parameters that affect the debonding strain of CFRP beams secured with different types of anchors. For this purpose, 34 small-scale beams were tested under four-point loading. Two (2) of them were control beams (no FRP, no anchors), 8 were strengthened with FRP at their tension sides, and the remaining 24 were secured with different types of anchor …

Improving Flood Forecasting Using Conditional Bias-Aware Assimilation Of Streamflow Observations And Dynamic Assessment Of Flow-Dependent Information Content, Haojing Shen

Civil Engineering Dissertations - Archive

Accurate forecasting of floods is a long-standing challenge in hydrology and water management. Data assimilation (DA) is a popular technique used to improve forecast accuracy by updating the model states in real time using the uncertainty-quantified actual and model-simulated observations. A particular challenge in DA concerns the ability to improve the prediction of hydrologic extremes, such as floods, which have particularly large impacts on society. Almost all DA methods used today are based on least squares minimization. As such, they are subject to conditional bias (CB) in the presence of observational uncertainties which often leads to under- and over-prediction of …

Investing In Bicycle Infrastructure To Spur Statewide Economic Growth Through Bicycle Tourism, Pedro Aguero Arroyo, Daniel P. Piatkowski, F. Alsaleem

Nebraska Department of Transportation: Research Reports

Bicycle tourism is a growing industry that has been shown by prior studies to contribute significantly to the economy of numerous states. The economic benefits of recreational bicycling are not limited to the direct effects of the transactions of bicyclists in related industries, but also spillover effects such as the reduction of automobile activity and its associated costs to society, or the decrease of the costs of obesity and inactivity to the healthcare system. This study focuses on the former and provides a qualitative and quantitative analysis of the economic impacts derived from recreational bicycling expenditure, as well as an …

A Big Data Approach For Improving Nebraska Cycling Routes, Fadi Alsaleem, Ali Al-Ramini, Mohammad Ali Takallou, Daniel P. Piatkowski

Nebraska Department of Transportation: Research Reports

More people are becoming interested in creating healthy lifestyle habits for themselves. It has been proved that cycling has several health benefits. Therefore, governments are planning towards more cycling-friendly infrastructures and environments. To understand the cycling activities in Nebraska, we analyze Strava data for the last three years, providing valuable insight into cycling activities for urban planning purposes.

We analyze commute and recreational cycling patterns varying between weekdays and weekends to identify peak hours. Moreover, we study the effect of weather on cycling activity patterns for the last three years. Also, we use the impact of the outside temperature as …

Utilizing Kryton Kim Technology In Bridge Deck And Rail Construction To Protect Against Chloride Ion Penetration, Mick Syslo, Wally Heyen, Lieska Halsey, David Hansen, Tim Kranson

Nebraska Department of Transportation: Research Reports

No abstract provided.

Best Practices To Address Issues Of Excess Aggregate Dust In Nebraska, Jiong Hu, Yong-Rak Kim, Temirlan Barissov, Shaya Gholami, Julia Grasley

Nebraska Department of Transportation: Research Reports

The negative impacts of an excessive amount of dust on concrete performance have been known and reported in different states. The extent and impact of dust on concrete performance, which depends not only on quantity but also on the nature of dust could be complicated. For example, clay coatings showed a more harmful impact on concrete performance compared with carbonates (limestone dust) or stone dust. While clays that weakly adhere to aggregate will be dispersed in the mixing water and could lead to the workability or air entrainment issues, clays that are strongly bonded to the aggregate surface will remain …

Mechanical Characterization And Wear Behavior Of Aerospace Alloy Aa2124 And Micro B4c Reinforced Metal Composites, Fazil N, V Venkataraman, Madeva Nagaral

Journal of Metals, Materials and Minerals

In the present investigation, the mechanical and wear properties of aerospace alloy AA2124-9wt%of B4C composites were displayed. The composites containing 9wt% of micro boron carbidein AA2124 alloy were synthesized by liquid metallurgy method through stir casting. For the composites, reinforcement particles were preheated to a temperature of 400°Cand afterward added in ventures of two stages into the vortex of liquid AA2124 alloy compound to improve the wettability anddispersion. Microstructural examination was carried out by SEM and elemental investigation was finished by EDS. Mechanical and wear properties of as cast AA2124 alloy and AA214-9wt% of B4C composites were evaluated as per …

Effect Of Amorphous Rice Husk Silica Additionon The Structure Of Asphalt Composite, Simon Sembiring, Agus Riyanto, Rudy Situmeang, Zipora Sembiring, Nita Susanti, Iqbal Firdaus

Journal of Metals, Materials and Minerals

In this study, modified asphalt composites were produced by adding silica extracted from rice husk.The mass ratios of asphalt to silica are 1:0, 1:1.6, 1:1.8, and 1:2 and calcined at the temperature of 150C for 6 h.The structural and microstructural characteristics of asphalt composites were examinedby x-ray diffraction (XRD),Scanning Electron Microscopy/Energy Dispersive x-ray (SEM-EDX) Spectroscopy and Differential Thermal Analysis (DTA-TGA),respectively. The XRDstudy revealed that the major phases were carbon and amorphous silica. The surface morphology of asphalt without silica addition presents a cluster of larger size than the cluster of asphalt with an addition of silica. The addition of silica …

Sparse Bases And Bayesian Inference Of Electromagnetic Scattering, John Lee

Theses and Dissertations

Many approaches in CEM rely on the decomposition of complex radiation and scattering behavior with a set of basis vectors. Accurate estimation of the quantities of interest can be synthesized through a weighted sum of these vectors. In addition to basis decompositions, sparse signal processing techniques developed in the CS community can be leveraged when only a small subset of the basis vectors are required to sufficiently represent the quantity of interest. We investigate several concepts in which novel bases are applied to common electromagnetic problems and leverage the sparsity property to improve performance and/or reduce computational burden. The first …

Experimental And Computational Analysis Of Progressive Failure In Bolted Hybrid Composite Joints, John S. Brewer

Theses and Dissertations

Composite materials are strong, lightweight, and stiff making them desirable in aerospace applications. However, a practical issue arises with composites in that they behave unpredictably in bolted joints, where damage and cracks are often initiated. This research investigated a solution to correcting the problem with composite bolted joints. A novel hybrid composite material was developed, where thin stainless steel foils were placed between and in place of preimpregnated composite plies during the cure cycle to reinforce stress concentrations in bolted joints. This novel composite was compared to control samples experimentally in quasi-static monotonic loading in double shear configuration in 9-ply …

Combining Bert With Contextual Linguistic Features For Identification Of Propaganda Spans In News Articles, Arjumand Younus, Muhammad Atif Qureshi

Conference papers

Recent endeavours at detection of propaganda in news articles treat this as a fine-grained problem of detecting it within fragments; and hence, transformer based embeddings perform decently in such detection. We build our propaganda detection framework on top of a transformer model simultaneously enriching it with contextual linguistic information of surrounding part-of-speech tags and LIWC categories the word itself belongs to. The evaluation outcomes being encouraging indicate a huge potential for this line of reasoning in natural language processing of news text.