Engineering Commons^™

Recent Developments In Timber Design & Its Impact On Carbon Emissions, Raquel Jackson

Spectra Undergraduate Research Journal

This paper explores recent developments in timber building designs and its potential towards reducing carbon emissions. Carbon dioxide emissions are a growing issue worldwide as urbanization and industrialization continues to increase. The rising concentration of carbon dioxide emissions pose significant concerns towards public welfare and environmental health. Despite current methods to reduce greenhouse gasses, carbon emissions remain difficult to reduce from steel and concrete industries. Increasing timber use in building design is a possible solution. Increasing more timber in building design can help reduce carbon emissions due to the carbon-absorbing properties of the construction material. Timber as a construction material …

Spatiotemporal Variability In Total Dissolved Solids And Total Suspended Solids Along The Colorado River, Godson Ebenezer Adjovu, Haroon Stephen, Sajjad Ahmad

Civil and Environmental Engineering and Construction Faculty Research

The Colorado River is a principal source of water for 40 million people and farmlands in seven states in the western US and the Republic of Mexico. The river has been under intense pressure from the effects of climate change and anthropogenic activities associated with population growth leading to elevated total dissolved solid (TDS) and total suspended solid (TSS) concentrations. Elevated TDS- and TSS-related issues in the basin have a direct negative impact on the water usage and the ecological health of aquatic organisms. This study, therefore, analyzed the spatiotemporal variability in the TDS and TSS concentrations along the river. …

Evaluating The Potential Of Geopolymer Concrete As A Sustainable Alternative For Thin White-Topping Pavement, Sathvik S. Chandra, Pshtiwan Shakor, Sarwar Mohmmad, Bankole O. Awuzie, Atul K. Singh, Abishek Rauniyar, M Karakouzian

Civil and Environmental Engineering and Construction Faculty Research

Introduction:

The construction industry uses a large quantity of natural materials in the production of concrete. Although attempts to incorporate green materials in concrete began years ago, not every building uses such materials today, and roadways, particularly, still rely on unsustainable materials.

Methods:

Therefore, this study used alternative materials, including fly ash, manufactured sand aggregates, and different molarities of alkaline activators, to incorporate waste byproducts in a geopolymer concrete white-topping pavement layer. Recent developments have led to the emergence of geopolymers as distinct classes of materials. In the 1990s, fly ash-based geopolymers became more popular than other kinds, as they …

Using Self-Efficacy Theory To Design Arduino Instruction For Novices: A Replication Study, Donald M. Johnson, Michael Pate, Christopher M. Estepp, George Wardlow

Journal of Research in Technical Careers

A replication study was conducted to determine the effectiveness of an instructional treatment based on self-efficacy theory when used with novice Arduino microcontroller users. Students (n = 32) in an introductory university agricultural systems technology course participated in a lesson on Arduino microcontrollers, circuit breadboarding, and Arduino programming which included four hands-on practice tasks, designed to provide students with positive mastery, vicarious and social persuasion experiences. Next, students completed a laboratory activity and were provided additional opportunities for mastery, vicarious, and social persuasion experiences. The one-group pretest-posttest design indicated the instructional treatment had significant (p < .001) and large effects in increasing students’ interest in Arduino, breadboarding self-efficacy, programming self-efficacy, and Arduino knowledge. These findings were consistent with the original study and provided additional evidence for self-efficacy theory as an effective model for developing instruction for novice Arduino users. Students’ written comments provided additional insight concerning the instructional treatment.

Non-Destructive Means Of Predicting Masonry Prism Strength Using Ultrasonic Pulse Velocity (Upv), Connor J. Barlow

UNLV Theses, Dissertations, Professional Papers, and Capstones

Current ASTM standards call for grouted masonry prisms to be tested for compressive strength at 28-days to ensure compliance with the structural design. In the event of failing tests, the subject samples may require redesign or reconstruction which can pose problems due to ongoing development around and including the prisms between the time of placement and obtaining test results. The purpose of this research is to determine if the use of ultrasonic pulse velocity (UPV) testing can be utilized to determine a correlation between prism composite strength of the masonry prism with ultrasound readings as to provide preliminary means of …

Trajectory Analysis For Driving Safety Quantification, Michael I. Chang

UNLV Theses, Dissertations, Professional Papers, and Capstones

In order to evaluate the efficacy of the skid recovery exercise in the Driver’s Edge teenage driving program, a process is established to determine the trajectories of vehicles from recorded videos, compare them in terms of similarity through dynamic time warping (DTW), and then analyze the similarity measurements to assess whether the program has a significant effect on driving ability by repeated measures analysis of variance (rANOVA). The video is analyzed by Harris corner detection and Lucas-Kanade optical flow method to ascertain the vehicle trajectories. A homography is then estimated to translate coordinates from video into real-world. The instructor and …

Three-Dimensional Finite Element Numerical Analysis Of Closely Spaced Foundations Resting On Clay Soil Supported With A Geocell Mattress Embedded In A Fly Ash Layer, Yahia Iskander

UNLV Theses, Dissertations, Professional Papers, and Capstones

This dissertation studied several models supported by a geocell mattress filled with fly ash material as a filling material on top of a clay soil bed. Two square rigid steel plates presenting footings with different spacing between them were subjected to loading. The effect of spacing between footings on the function of the system was investigated by measuring the footings load and settlement.In the past, limited cases were studied for closely spaced footings. The subject of two closely spaced footings on clay soil supported by geocell has not been researched before. Most of the previous research was on sandy soil; …

Time-Dependent Wetting Behavior Of Hydrogels, Amir Kashani

UNLV Theses, Dissertations, Professional Papers, and Capstones

Hydrogels are 3-D polymers with hygroscopic properties that enable them to absorb and retain large amounts of water. In many applications such as biomedical applications, including drug delivery, wound healing, tissue engineering, biosensors, and contact lenses, agriculture, food and beverage, cosmetics, and environmental, hydrogels also need to maintain a high degree of wetting in order to ensure effective functionality and interaction with surrounding fluids or tissues in desired applications. The combination of wetting and absorptive behavior of hydrogels that are often encountered in biomedical, biological, industrial and the mentioned applications presents a challenging physical problem that is not completely understood. …

Enhanced Iot-Based Electrocardiogram Monitoring System With Deep Learning, Jian Ni

UNLV Theses, Dissertations, Professional Papers, and Capstones

Due to the rapid development of computing and sensing technologies, Internet of Things (IoT)-based cardiac monitoring plays a crucial role in providing patients with cost-efficient solutions for long-term, continuous, and pervasive electrocardiogram (ECG) monitoring outside a hospital setting. In a typical IoT-based ECG monitoring system, ECG signals are picked up by sensors located on the edge, and then uploaded to the remote cloud servers. ECG interpretation is performed for the collected ECGs in the cloud servers and the analysis results can be made instantly available to the patients as well as their healthcare providers.In this dissertation, we first examine the …

A One-Dimensional Analysis Of A Microbial Fuel Cell For Efficient Acetate Removal And Power Density Output, David Rouhani

UNLV Theses, Dissertations, Professional Papers, and Capstones

Microbial fuel cells (MFCs) are electrochemical devices that utilize microorganisms to convert organic matter into electrical energy. MFCs have been discussed to have potential application for sustainable wastewater treatment due to their ability to generate electricity while simultaneously treating contaminated water. To optimize MFC performance, numerical models can be used to understand the complex electrochemical and biological processes occurring in the system. In this study, a numerical model was developed to simulate the performance of MFCs under varying operating conditions and to investigate the performance of a MFC for treating wastewater fuel. More specifically, the MFC was modeled to oxidize …

Development Of An Automated Gpib System For Characterization Of Sige Avalanche Photodiodes, David A. Santiago

UNLV Theses, Dissertations, Professional Papers, and Capstones

Photon counting is a technique in many modern technologies such as medical imaging and LiDAR systems. Photon counting is needed in many aspects of the development process for these technologies from photodetector characterization to operation of the finished product. This thesis will serve to solve the challenge of quantifying photodetector performance using automating test equipment with known software packages such as MATLAB to be able tocharacterize photodetectors in an efficient manner. A custom MATLAB program has been developed to interface with various instrumentation using a General-Purpose Interface Bus (GPIB) and a Prologix GPIB-USB controller that will be able to send …

Monitoring And Classification Of Tissue Perfusion Through The Combined Use Of Thermal, Rgb, And Laser Speckle Contrast Imaging, Ivan Soto

UNLV Theses, Dissertations, Professional Papers, and Capstones

In cooperation with the UNLV School of Medicine, this thesis is part of a bigger project aimed at developing a post-op surgery device for the constant unattended monitoring of a patient’s tissue. This device is intended to monitor areas of surgical sites and detect any complications without the need for continuous supervision by medical professionals. One such complication includes inadequate tissue perfusion, or a lack of blood flow reaching a patient’s tissue. The role of this thesis is to fit a convolutional neural network model to the available data gathered from voluntary participants and attempt to classify the data as …

Simulating Condensation In The Theory Of Classical Nucleation, David Vallet

UNLV Theses, Dissertations, Professional Papers, and Capstones

The scope of this thesis is to numerically investigate condensation that occurs in transonic and supersonic flows. Condensation shocks are a phenomenon that occurs within converging-diverging nozzles. There are many applications forconverging-diverging nozzles, such as thermovapour compressors (TVC), which are largely used for desalination. As water resources become more precious within the western United States there is a need to develop cost effective solutions for cleaning water. Steam generator power stations are another application where enhanced simulations and accuracy of design could improve efficiency and save on carbon emissions. Traditionally, numerical designs of transonic flows have been conducted with either …

Information-Theoretic Model Diagnostics (Infomod), Armin Esmaeilzadeh

UNLV Theses, Dissertations, Professional Papers, and Capstones

Model validation is a critical step in the development, deployment, and governance of machine learning models. During the validation process, the predictive power of a model is measured on unseen datasets with a variety of metrics such as Accuracy and F1-Scores for classification tasks. Although the most used metrics are easy to implement and understand, they are aggregate measures over all the segments of heterogeneous datasets, and therefore, they do not identify the performance variation of a model among different data segments. The lack of insight into how the model performs over segments of unseen datasets has raised significant challenges …

Metastability And Degradation In Cu(In,Ga)Se2 Thin-Film Solar Cells, Mohsen Jahandardoost

UNLV Theses, Dissertations, Professional Papers, and Capstones

Cu(In,Ga)(S,Se)2 or CIGS is a thin-film semiconductor that has shown a device efficiency of 23.35% and 24.2% for single-junction and perovskite/CIGS tandem solar cells, respectively. CIGS offers promising properties such as tunable bandgap and ease of processing making them great candidates for thin-film tandem devices. However, knowledge of the effect of material defects, buffer materials, and post-deposition treatment (PDT) on degradation and metastability behavior in these devices is not well understood.In this dissertation, metastability and long-term degradation of CIGS thin-film solar cells have been investigated under combinatorial stress factors of heat, light, and voltage bias to systematically understand the effect …

Investigating Haloacetonitrile (Han) Formation Potential From Nitrogenous Antibiotics And Agrochemicals, Kazi Shafayet Haider

UNLV Theses, Dissertations, Professional Papers, and Capstones

Disinfection can promote safe drinking water. Chlorine and chloramines are the two most used disinfectants. While these disinfectants are effective in inactivating disease-causing pathogens, they also produce hazardous byproducts when they react with organic compounds (precursors). Nitrogenous disinfection byproducts (N-DBPs) are more toxic than their counterparts. The increased use of nitrogen-based agrochemicals and antibitics has led to their detection in different water sources. The presence of secondary amine and aniline in these compounds can act as a source of reactive nitrogen to form N-DBPs. In addition, the increased concentration of bromide in water systems due to anthropogenic activities can enhance …

Synthesis Of Novel Chiral Phosphorothioic Acid Organocatalysts And Application To Synthetic Methodology, Parsa Azaei

Undergraduate Research Symposium Posters

Much research efforts have been centered towards the synthesis of novel Bronsted acid catalysts. These organocatalyst enable synthesis of natural products, pharmaceuticals, and bioactive small molecules under toxic-metal-free conditions by donating their protons, while not being consumed in the reaction. Chiral phosphorothioic acid have significant potential as novel organocatalysts due to their high modifiability of chirality and acidity under environmentally friendly conditions; however, synthesis of these organocatalysts are far and in between. Therefore, our research aimed to i) synthesize novel phosphorothioic acid organocatalysts and ii) to apply these novel catalysts toward new methodology development.

Nuclear Power Plant In Las Vegas, Ryan W. Murray

Undergraduate Research Symposium Posters

This research focuses on the impact of a “Nuclear Power Plant in Las Vegas” or ‘NPP in LV’ for short. Nuclear power is clean, has no greenhouse gas emissions, and has a moderate cost of kilowatt hours. Las Vegas, or more specifically Clark County uses Gas power plants to produce a majority of their electricity. My project will show what a nuclear plant could do if built in the city of Las Vegas. What is a Nuclear power plant? The EIA’s definition is “A nuclear power plant uses the heat that a nuclear reactor produces to turn water into steam, …

Identification Of Factors Contributing To Traffic Crashes By Analysis Of Text Narratives, Cristian D. Arteaga-Sanchez

UNLV Theses, Dissertations, Professional Papers, and Capstones

The fatalities, injuries, and property damage that result from traffic crashes impose a significant burden on society. Current research and practice in traffic safety rely on analysis of quantitative data from crash reports to understand crash severity contributors and develop countermeasures. Despite advances from this effort, quantitative crash data suffers from drawbacks, such as the limited ability to capture all the information relevant to the crashes and the potential errors introduced during data collection. Crash narratives can help address these limitations, as they contain detailed descriptions of the context and sequence of events of the crash. However, the unstructured nature …

Nexuscapes: A Landscape Approach For A Transdisciplinary Water-Energy-Food Nexus Decision-Making Process, Fortino Acosta

UNLV Theses, Dissertations, Professional Papers, and Capstones

This study develops a reliable transdisciplinary framework for complex ecological and social systems by characterizing, mapping, typifying, assessing, and testing enhanced water-energy-food nexus scenarios under critical time constraints, specialized skills, or sensitive data accessibility. Detached management of limited essential resources like fresh water, reliable energy from renewable sources, and nutritious food can jeopardize regional economies and governance. Using a novel landscape approach, this study recommends a decision-making the framework focused on the circular economy that induces collaboration among diverse sectors and brings strategic coordination, specificity, and magnitude to the proposed solutions. The study elaborates on a decision-making tool that integrates …

Application Of Experimentally Calibrated Numerical Models For Prediction Of Composite Masonry Prism Strength, James Bristow

UNLV Theses, Dissertations, Professional Papers, and Capstones

The composite masonry prism test is a common laboratory test to determine the compressive strength of a set of masonry prisms (f’mt) to verify that the composite masonry prism assembly, and more importantly, the constituent materials, are providing adequate strength. While constructing masonry structures, the subcontractors, designers, and inspectors rarely provide continuous supervision or inspection of the construction process. Accordingly, verification of grout mix design, mixed proportions, proper installation of blocks, placement of mortar, dimensions of joints, etc. are more traditionally performed on a periodic basis instead. However, through the use and review of the composite masonry prism test results, …

Effects Of Particle Size And Replacement Proportion Of Post-Consumer Glass In Concrete, Negasi Gebremichael

UNLV Theses, Dissertations, Professional Papers, and Capstones

Concrete, next to water, is the most used material (Gagg, 2014), which consumes natural or manufactured aggregates and resource-intensive cement. Concrete is also a more wasteful construction material than timber and steel. Depleting the natural resource due to aggregate extraction and the environmental unfriendliness of cement production have left the construction industry with no choice. Reducing waste, reusing, or recycling can help conserve natural resources. In this regard, the construction industry constantly seeks full or partial replacement of concrete aggregates and cement with recycled material. Glass is a candidate for replacing the three major components: cement, fine aggregate, and coarse …

Towards The Electronic Response Of Carbon-Based Van Der Waals Heterostructures In A Diamond Anvil Cell, George Thomas Foskaris

UNLV Theses, Dissertations, Professional Papers, and Capstones

The nanoscale regime of materials has been at the forefront of research and interest in condensed matter physics for many years. In a merger of the fields of two-dimensional (2D) materials and high pressure physics, we present an investigation of the electronic response of carbon-based, van der Waals (vdW) heterostructures in a diamond anvil cell (DAC). Combining these fields presents us with the ability to study the characteristics of such systems both optically, and through electrical transport. Properties such as conductance, band structure, and layer number are considered. The samples in this study are assembled using exfoliation and stacking techniques …

Dynamic Surface Tension Of Surfactants Through Separation Of Diffusion And Dilation Effects, Brandon Ortiz

UNLV Theses, Dissertations, Professional Papers, and Capstones

Surfactants are biphilic monomers that adsorb to interfaces and have the ability to reduce interfacial tension. From this reduction in interfacial tension, surfactants are able to function as emulsifiers, detergents, and wetting agents among a variety of other things. Despite their ubiquity surfactants and surfactant behaviors, in particular those in highly dynamic environments, are not yet well characterized. In these environments, surfactants undergo significant distortions to droplet, bubble, and foam geometries which induce changes to the surface tension. This establishes a need to understand how surfactants respond to distortions of geometry through diffusion and dilational effects. To address this need, …

Developing A Hands-On Class Exercise For Modular Construction, 3d Design, And 4d Schedule, Kyle A. Kithas

UNLV Theses, Dissertations, Professional Papers, and Capstones

Modular construction shows promise as a viable alternative to stick-built construction. A major challenge with the widespread adoption of modular construction is the construction industry’s focus on minimizing risk and defaulting to the comfort and familiarity of stick-built construction. This pattern can be broken through an educational paradigm shift in the way architecture, engineering, and construction are taught in school. Integrating modular construction education into higher education is presented to increase the future adoption of modular construction and expand the comfort zones of future industry leaders. This thesis proposes that current curriculum be augmented to teach the modular approach in …

Development And Application Of A Safety Index For Transit Stops: A Case Study From Las Vegas, Nevada, Rithesh Shivuni

UNLV Theses, Dissertations, Professional Papers, and Capstones

This research developed a methodology to evaluate safety proximate to transit stops through a Safety Index, identified key factors associated with fatal crashes proximate to bus transit stops, and illustrated the applications of these using a case study based on the Las Vegas metropolitan area in Nevada, USA. The methodology is based on motor vehicle crashes that involve pedestrians recorded in the proximity of transit stops, and the severity of the crash outcomes. It focused on crashes which involved pedestrians that occurred within walking distances of individual transit stops. The severity of the crash outcomes was classified based on the …

Measuring Impacts And Vibrations On A Volumetric Modular House During Transportation, Seung Ho Song

UNLV Theses, Dissertations, Professional Papers, and Capstones

The U.S. construction industry is experiencing an increase in demand for further implementation of modular construction due to the significant productivity and project cost-reducing benefits it provides. However, there exist challenges with the modular method, and many of them are well covered by previous studies, except for the effects of transportation-induced impact/vibration on volumetric modules. A previous study examined the effects of transportation-induced impact/vibration on a timber-framed module and identified some valuable findings. But, it did not explore other types of modules, height considerations, and the differences in the magnitude of impact/vibration due to different module maneuvers on the road. …

A Control Integrated Circuit For A Hysteretic Flyback Power Converter, Armani Alvarez

UNLV Theses, Dissertations, Professional Papers, and Capstones

This Thesis reports the design, simulation, and layout of a switching power supply controller chip for a fly-back switching power supply. The controller chip was designed using ON’s Semiconductor C5 process. The resulting switching power supply using the controller chip consists of using various off-chip components such as a power MOSFET, transformer, and capacitors. The main components used in the integrated circuit include a bandgap reference voltage circuit which outputs a reference voltage of 1.25V, a ring oscillator having a nominal frequency of 5MHz, a high-gain comparator, and a buffer that can drive a 5pF capacitor. Under normal simulation conditions …

Mechanoelectrical Behavior In Polyvinyl Chloride (Pvc) Based Soft Polymer Gel Smart Sensors For Soft Robotic Applications, Justin Neubauer

UNLV Theses, Dissertations, Professional Papers, and Capstones

Polyvinyl chloride (PVC) gels are a class of electroactive polymer that contain a PVC-based polymeric lattice and various amounts of plasticizer. PVC and plasticizer are industrially available and are commonly used in a wide range of applications including cable insulation, flexible hosing, and healthcare equipment. There are many plasticizer types available, some being extremely biocompatible with implementations in food-safe applications and even food additives for human consumption. Plasticizer weakly bonds to the long polymerized chains of the polymer lattice decreasing the modulus of the composite material. By adding excessive amounts of plasticizer, the bonding sites of these long carbon chains …

Automated Approach For The Enhancement Of Scaffolding Structure Monitoring With Strain Sensor Data, Sayan Sakhakarmi

UNLV Theses, Dissertations, Professional Papers, and Capstones

Construction researchers have made a significant effort to improve the safety of scaffolding structures, as a large proportion of workers are involved in construction activities requiring scaffolds. However, most past studies focused on design and planning aspects of scaffolds. While limited studies investigated scaffolding safety during construction, they are limited to simple cases only with limited failure modes and simple scaffolds. In response to this limitation, this study aims to develop an automated scaffold monitoring approach capable of monitoring large scaffolds. Accordingly, this study developed an automated scaffold safety monitoring framework that leverages sensor data collected from a scaffold, scaffold …