Engineering Commons^™

Cost Comparison Of Cement Concrete And Polymer Concrete Manholes In Sewer Systems, Sayan Sakhakarmi

UNLV Theses, Dissertations, Professional Papers, and Capstones

Cement concrete manholes are generally used in sewer networks in the United States. However, these concrete manholes are highly vulnerable to chemical corrosion and require frequent maintenance and replacement. Polymer concrete manholes as a substitute to the cement concrete manholes in water and wastewater pipelines have proved to have longer service life and more resistance to various chemical corrosions than normal concrete manholes. Despite the benefits that polymer concrete manholes offer, the higher initial installation cost has been a barrier to its wide application in public works. This study has been conducted to compare the cost of cement concrete manholes …

Comparison Of Simulation Methods Of Single And Multi-Bit Continuous Time Sigma Delta Modulators, Benju Koirala

UNLV Theses, Dissertations, Professional Papers, and Capstones

Continuous time Sigma Delta Modulators (CT ΣΔMs) are a type of analog to digital converter (ADC) that are used in mixed signal systems to convert analog signals into digital signals. ADCs typically require antialiasing filter; however antialiasing filters are inherent in CT ΣΔMs, and therefore they require less circuitry and less power than other ADC architectures that require separate antialiasing filters. As a result, CT ΣΔM ADC architectures are preferred in many mixed signal electronic applications.

Because of the mixed signal nature of CT ΣΔMs, they can be difficult to simulate. In this thesis, various methods for simulating single-bit and …

Surface Hydrologic Modeling And Analyzing Watershed Hydrologic Response To Landcover Change, Roshan Poudel

UNLV Theses, Dissertations, Professional Papers, and Capstones

Urban flooding is the most frequently occurring disaster in rapidly urbanizing cities. Rapid urbanization in general, is characterized by an increase in the total impervious surface area, which means less soil cover for the stormwater to infiltrate and a greater volume of runoff from the area in case of a storm event. This increased volume of surface runoff, if not drained, results in urban flooding. Urban flooding can cause serious economic and environmental damages by disrupting transportation and spreading pollution. It is therefore, essential to understand the cause, behavior and effects of urban flooding so as to minimize the risks …

The Effects Of Exhaust Vent Location On Thermal Comfort Inside The Residential Buildings Equipped With An Evaporative Cooling System, Armin Saraei

UNLV Theses, Dissertations, Professional Papers, and Capstones

Inlet and outlet conditions, Including size and location, have significant effects on the air distribution, temperature, humidity and thermal comfort in the buildings. In the current study, various strategies are presented for exhaust air vents and the effects of inlet and outlet vents locations are evaluated on providing thermal comfort in the residential and industrial buildings. To provide thermal comfort, three key factors need to be investigated based on ASHRAE standard 55- 2013 as follows: Comfort Zone, Thermal Sensation and Draft Rate. Flow distribution is studied as well in order to investigate the strategies, which make more vorticity in the …

Theoretical And Experimental Investigation On The Multiple Shape Memory Ionic Polymer-Metal Composite Actuator, Qi Shen

UNLV Theses, Dissertations, Professional Papers, and Capstones

Development of biomimetic actuators has been an essential motivation in the study of smart materials. However, few materials are capable of controlling complex twisting and bending deformations simultaneously or separately using a dynamic control system. The ionic polymer-metal composite (IPMC) is an emerging smart material in actuation and sensing applications, such as biomimetic robotics, advanced medical devices and human affinity applications. Here, we report a Multiple Shape Memory Ionic Polymer-Metal Composite (MSM-IPMC) actuator having multiple-shape memory effect, and is able to perform complex motion by two external inputs, electrical and thermal. Prior to the development of this type of actuator, …

An Investigation Of Employment And Wage Distribution In The Construction Industry By Race/Ethnicity And Gender, Binit Kumar Shrestha

UNLV Theses, Dissertations, Professional Papers, and Capstones

One of the largest job providers in the U.S, is the construction industry, an industry that suffers from critical problems pertaining to a labor shortage. Yet the industry also struggles with insufficient interest and inconsistent participation from underrepresented demographic groups. To address the issue of workforce income inequality and bias, the industry must better understand the current situation regarding inequality; it needs to pinpoint some basic problems. To do so, analysts must scrutinize the following aspects: 1) the current differences within the construction workforce by race/ethnicity and gender with regards to the total employment and 2) the current disparity within …

Understanding The Long-Term Changes In Hydrologic Processes On A Watershed Scale Due To Climate Variability And Change, Chao Chen

UNLV Theses, Dissertations, Professional Papers, and Capstones

In the past century, the population explosion and economic development have resulted in global warming, which has raised a series of concerns, such as sea-level rise, food security, and water resources management. The water flow patterns and features experience both short-term and long-term changes in responses to the changes in the hydrologic processes and meteorologic conditions. On a watershed scale, it is crucial to understand, quantify, and attribute the influences of climate change on the local water resources system. Such understanding can be of great help to undertake local water management tasks, such as flood control, reservoir operation, ecosystem services, …

Radiative Contour Mapping Using Uas Swarm, Zachary Cook

UNLV Theses, Dissertations, Professional Papers, and Capstones

The work is related to the simulation and design of small and medium scale unmanned aerial system (UAS), and its implementation for radiation measurement and contour mapping with onboard radiation sensors. The compact high-resolution CZT sensors were integrated to UAS platforms as the plug-and-play components using Robot Operation System. The onboard data analysis provides time and position-stamped intensities of gamma-ray peaks for each sensor that are used as the input data for the swarm flight control algorithm. In this work, a UAS swarm is implemented for radiation measurement and contour mapping. The swarm of UAS has advantages over a single …

Investigation Of Setting Time And Compressive Strength Of Ready-Mixed Concrete Blended With Returned Fresh Concrete, Negasi Niguse Gebremichael

UNLV Theses, Dissertations, Professional Papers, and Capstones

The Center for Sustainable Transportation Infrastructure (CSTI), in its 2012 study, estimated that out of all the concrete leaving the plant, between 2% and 7% of concrete returns to the plant unused as a returned fresh concrete (RFC). Disposal of both the truck wash water and RFC is a growing concern for the industry. Most industry personnel contacted during the investigation, agree that reusing is superior to recycling of this substantial RFC economically and environmentally. This study will determine if the reuse of RFC in subsequent batches compromises the quality of newly blended concrete.

The effect of RFC on fresh …

Numerical Characterization Of The Flow Field And Heat Transfer Inside The Receiver Of A Parabolic Trough Solar Collector Carrying Supercritical Co2, Samad Gharehdaghimollahajloo

UNLV Theses, Dissertations, Professional Papers, and Capstones

The aim of this research is to provide a detailed numerical analysis of flow field and heat transfer inside the heat collecting element of a parabolic trough collector. The parabolic trough collector is used as the boiler in a direct Super Critical Carbon Dioxide (S-CO2) Brayton cycle.

A single collector is modeled and analyzed with different inlet conditions. The working fluid is supercritical since its pressure is increased to above critical pressure in the compressor while its temperature reaches 300 °C after passing through the recuperators and before entering the solar field. For the first time, this research considers both …

Controlled Electrochemical Reduction Of Gold And Palladium Metal Precursors In Polyaniline, Nicole Goodwin

UNLV Theses, Dissertations, Professional Papers, and Capstones

Polyaniline (PANI) has been extensively studied due to its unique electrochemical properties. The conjugated polymer is conductive with high chemical stability below 100°C, mechanical strength, and large surface area. The applications of PANI have included chemical sensing, corrosion inhibition coatings, light emitting diode and as a substrate for metal composite catalysts. Both chemical and electrochemical methods have been developed and utilized in the synthesis of PANI/metal composites. The simultaneous reduction of aniline and metal precursor produces a composite of PANI encapsulated metal, reducing the active surface area available for catalysis. Alternatively, chemical reduction of the metal precursor into preformed PANI …

Evaluating The Chemical And Biological Stability Of Finished Waters Blended For Direct Potable Reuse In A Simulated Distribution System, Assumption Grimaldi

UNLV Theses, Dissertations, Professional Papers, and Capstones

This work evaluated the impacts of blending several different high grade recycled waters with conventional source waters for direct potable reuse (DPR) applications. Bench-scale laboratory tests were conducted for recycled water-source water blends from four participating facilities that have either considered adopting DPR or have already implemented DPR as a feasible approach to overcome water scarcity. The chemical and biological stability of the finished waters was investigated after pipe rig incubation to simulate the quality of blended waters that had aged in a potable water distribution system. The effects of blend ratio, reclaimed water treatment, and source water quality were …

Parents' Perceptions Of Smartphone Use And Parenting Practices, David Jackson Johnson

UNLV Theses, Dissertations, Professional Papers, and Capstones

The present study is a qualitative examination aiming to gain insight into parents’ perceptions of their smartphone use and the effects it may be having on their children as well as parenting practices. Participants (N=12) were smartphone using parents that consisted mostly of young college-educated females. Thematic analysis of individual interviews resulted in five primary themes: (1) Disengagement, (2) Concern for Future, (3) Change in Social Norms, (4) Boundaries, and (5) Cognitive Dissonance. These findings indicate significant effects parental smartphone use is having in the lives of study participants. These thematic findings call for additional research examining the impact parental …

Surface And Interface Characterization Of Solution-Processed Metal Oxides And Pedot:Pss Using Photoelectron Spectroscopy, Lynette M. Kogler

UNLV Theses, Dissertations, Professional Papers, and Capstones

Solution-processed materials are appealing for use in printable electronics as a means to lower production costs, but precise control of the process is crucial for achieving the desired properties in the final materials and their interfaces. Electronic interface properties depend on both the involved materials and their fabrication processes, impacting the development and commercialization of these materials. Analyzing the chemical and electronic structure of these materials, particularly at the surfaces and interfaces, is important not only for insuring that the materials have the desired properties, but also for understanding the effects of the fabrication process and how to modify properties …

Improving Hyperspectral Subpixel Target Detection Using Hybrid Detection Space, Ruixing Li

UNLV Theses, Dissertations, Professional Papers, and Capstones

A Hyper-Spectral Image (HSI) has high spectral and low spatial resolution. As a result, most targets exist as subpixels, which pose challenges in target detection. Moreover, limitation of target and background samples always hinders the target detection performance. In this thesis, a hybrid method for subpixel target detection of an HSI using minimal prior knowledge is developed. The Matched Filter (MF) and Adaptive Cosine Estimator (ACE) are two popular algorithms in HSI target detection. They have different advantages in differentiating target from background. In the proposed method, the scores of MF and ACE algorithms are used to construct a hybrid …

Effects Of Contract Procurement Factors On Performance Of Transportation Projects, Ruiko Maharjan

UNLV Theses, Dissertations, Professional Papers, and Capstones

Cost and schedule savings are the main measures of a project’s success. Several factors affect the cost and schedule performances in a construction project, such as design changes, material, labor and equipment shortages, unpredictable weather conditions, and errors & omissions in contract documents.Some studies have shown that either the construction cost or the schedule performance of a project was dependent on the procurement factors, namely: bid cost, number of bidders, the bid cost deviation between the first and second bidder, the liquidated damage rate per day, the type of a contract, and the project location. However, a comprehensive study on …

Simulating Distributed Battery And Solar Array Placement For Voltage Regulation, Michael Misch

UNLV Theses, Dissertations, Professional Papers, and Capstones

Energy storage has been around for many years in the US, mainly in the form of pumped hydro. However, in recent years, other storage technologies have developed quickly, with lithium ion batteries receiving significant investment and delivering technological and price improvements. Electricity storage has the potential to assist the US in transitioning to a smarter grid, as well as enabling increasing amounts of renewable generation to connect to the grid, without costly reinforcement works. Electricity storage can be co-located with power generation assets, installed along distribution systems for network services, or placed behind the meter, i.e., on the customer’s premises. …

Remote Sensing Of The Environmental Impacts Of Utility-Scale Solar Energy Plants, Mohammad Masih Edalat

UNLV Theses, Dissertations, Professional Papers, and Capstones

Solar energy has many environmental benefits compared with fossil fuels but solar farming can have environmental impacts especially during construction and development. Thus, in order to enhance environmental sustainability, it is imperative to understand the environmental impacts of utility-scale solar energy (USSE) plants. During recent decades, remote sensing techniques and geographic information systems have become standard techniques in environmental applications. In this study, the environmental impacts of USSE plants are investigated by analyzing changes to land surface characteristics using remote sensing. The surface characteristics studied include land cover, land surface temperature, and hydrological response whereas changes are mapped by comparing …

Meshless Method For Simulation Of Compressible Flow, Ebrahim Nabizadeh Shahrebabak

UNLV Theses, Dissertations, Professional Papers, and Capstones

In the present age, rapid development in computing technology and high speed supercomputers has made numerical analysis and computational simulation more practical than ever before for large and complex cases. Numerical simulations have also become an essential means for analyzing the engineering problems and the cases that experimental analysis is not practical. There are so many sophisticated and accurate numerical schemes, which do these simulations. The finite difference method (FDM) has been used to solve differential equation systems for decades. Additional numerical methods based on finite volume and finite element techniques are widely used in solving problems with complex geometry. …

Specification Of Mixed Logit Models Using An Optimization Approach, Cristian David Arteaga Sanchez

UNLV Theses, Dissertations, Professional Papers, and Capstones

Mixed logit models are a widely-used tool for studying discrete outcome problems. Modeling development entails answering three important questions that highly affect the quality of the specification: (i) what variables are considered in the analysis? (ii) what are going to be the coefficients for these variables? and (iii) what density function these coefficients will follow? The literature provides guidance; however, a strong statistical background and an ad hoc search process are required to obtain the best model specification. Knowledge of the problem context and data is required. Given a dataset including discrete outcomes and associated characteristics the problem to be …

Cyclist Detection, Tracking, And Trajectory Analysis In Urban Traffic Video Data, Farideh Foroozandeh Shahraki

UNLV Theses, Dissertations, Professional Papers, and Capstones

The major objective of this thesis work is examining computer vision and machine learning detection methods, tracking algorithms and trajectory analysis for cyclists in traffic video data and developing an efficient system for cyclist counting. Due to the growing number of cyclist accidents on urban roads, methods for collecting information on cyclists are of significant importance to the Department of Transportation. The collected information provides insights into solving critical problems related to transportation planning, implementing safety countermeasures, and managing traffic flow efficiently. Intelligent Transportation System (ITS) employs automated tools to collect traffic information from traffic video data. In comparison to …

Optimization Of Prosthetic Hands: Utilizing Modularity To Improve Grip Force, Grasp, And Versatility, Jordan William Harris

UNLV Theses, Dissertations, Professional Papers, and Capstones

It has been demonstrated that although many varieties of upper limb prosthetics exist, commercially available prosthetics are outdated and unsatisfactory. Ineffectiveness and limitations have led to some prosthesis wearers having to own multiple devices, whereas others have given up on them entirely. Even though ample research has been conducted to design and test new hand designs, the industry appears to rest in an overall stagnated state.

It was proposed here, that one problem with prosthetic research is an excess of variables involved in testing, and therefore the improper application of the scientific method. It seems that each time a research …

Automated Quantification Of White Blood Cells In Light Microscopic Images Of Injured Skeletal Muscle, Yang Jiao

UNLV Theses, Dissertations, Professional Papers, and Capstones

Muscle regeneration process tracking and analysis aim to monitor the injured muscle tissue section over time and analyze the muscle healing procedure. In this procedure, as one of the most diverse cell types observed, white blood cells (WBCs) exhibit dynamic cellular response and undergo multiple protein expression changes. The characteristics, amount, location, and distribution compose the action of cells which may change over time. Their actions and relationships over the whole healing procedure can be analyzed by processing the microscopic images taken at different time points after injury. The previous studies of muscle regeneration usually employ manual approach or basic …

Evaluation Of The Properties Of Rubberized Asphalt Binders And Mixtures, Kazem Jadidirendi

UNLV Theses, Dissertations, Professional Papers, and Capstones

Rubber modified binder samples are tested and evaluated based on SHRP requirements. Best rubber content is suggested for modifying binder. Rubber modified asphalt mixtures were manufactured and tested. Based on Hveem stability and volumetric properties of asphalt mixtures, optimum binder content is evaluated and reported. Performance properties of asphalt mixtures made with various rubber size and method were analyzed and compared. An ultrasound measurement performed on asphalt mixture samples and the results were analyzed. It is discovered that rubber improves asphalt viscosity and resistance to rutting deformation. Rubber also increases asphalt’s dynamic modulus.

Sparse Mri And Ct Reconstruction, Ali Pouryazdanpanah Kermani

UNLV Theses, Dissertations, Professional Papers, and Capstones

Sparse signal reconstruction is of the utmost importance for efficient medical imaging, conducting accurate screening for security and inspection, and for non-destructive testing. The sparsity of the signal is dictated by either feasibility, or the cost and the screening time constraints of the system. In this work, two major sparse signal reconstruction systems such as compressed sensing magnetic resonance imaging (MRI) and sparse-view computed tomography (CT) are investigated.

For medical CT, a limited number of views (sparse-view) is an option for whether reducing the amount of ionizing radiation or the screening time and the cost of the procedure. In applications …

Improving Pattern Recognition And Neural Network Algorithms With Applications To Solar Panel Energy Optimization, Ernesto Zamora Ramos

UNLV Theses, Dissertations, Professional Papers, and Capstones

Artificial Intelligence is a big part of automation and with today's technological advances, artificial intelligence has taken great strides towards positioning itself as the technology of the future to control, enhance and perfect automation. Computer vision includes pattern recognition and classification and machine learning. Computer vision is at the core of decision making and it is a vast and fruitful branch of artificial intelligence. In this work, we expose novel algorithms and techniques built upon existing technologies to improve pattern recognition and neural network training, initially motivated by a multidisciplinary effort to build a robot that helps maintain and optimize …

Impacts Of Ozone Dose And Empty Bed Contact Time On Bulk Organic Removal And Disinfection Byproduct Mitigation In Ozone-Biofiltration Systems, Mayara Aquino

UNLV Theses, Dissertations, Professional Papers, and Capstones

In areas where water shortages have compromised water supplies, potable reuse is a promising solution. However, additional research is needed to identify and/or optimize cost-effective treatment technologies to demonstrate compliance with potable reuse regulations. Treatment trains employing reverse osmosis (RO) and advanced oxidation, a combination known as ‘full advanced treatment’ (FAT), are required by the California Division of Drinking Water (CDDW) for surface water augmentation and direct injection of recycled water into local aquifers. A maximum concentration of 0.5 mg/L of wastewater-derived total organic carbon (TOC) is also required by CDDW in all groundwater recharge applications. This appears to be …

Design, Fabrication And Testing Of A Capacitive Sensor Using Delta-Sigma Modulation, Charikleia Tsagkari

UNLV Theses, Dissertations, Professional Papers, and Capstones

Capacitive sensing is a popular technology employed in billions of products and millions of applications. This Thesis details the design, layout and characterization of an Integrated Circuit (IC) that employs Delta-Sigma Modulation (DSM) for sensing capacitance. The chip, measuring 1.5 mm x 1.5 mm, was designed in On Semiconductor’s C5 process and was manufactured by MOSIS.

The sensing circuit links linearly the ratio of a “test” to a “reference” capacitance to the output of a Delta-Sigma Modulator. The equations that describe the operation of the sensing circuit are derived. Besides the sensing circuit, there is a non-overlapping clock generator that …

Re-Evaluation Of Acceptance Testing Criteria For Structural Masonry Using The Prism Test Method, James Bristow

UNLV Theses, Dissertations, Professional Papers, and Capstones

The current acceptance criteria for structural masonry in accordance with International Building Code allows for the prism test method to be used. However, without a proper understanding of the effects of variable material properties such as individual masonry unit compressive strength and the various material moduli of elasticity, as well as the effect of field conditions on the unit’s performance, masonry prisms may “fail” to reach the design compressive strength (f’m).

By identifying causes of failure and evaluating the failure magnitude, it is concluded that when the masonry prism test method is utilized for acceptance testing of as-built masonry structures, …

Em Wave Interaction With A Bounded Plasma Column Supporting An Electron Beam, Asmelash Teshome Beshah

UNLV Theses, Dissertations, Professional Papers, and Capstones

In this thesis, the disruption of an incoming external transverse electromagnetic wave by an inhomogeneous plasma with energetic electron beam is examined. The plasma-beam characteristics are motivated by theory and experiment. Wave-plasma interactions and wave propagation and reflection in and from a plasma medium is studied. Physical sources such as the plate current density are considered. The inhomogeneity of the plasma slab supporting the energetic electron beam is partially built into the supported fields. The wave-plasma-beam interaction is examined over a wide parameter space. Absorption or reflection of electromagnetic waves can be achieved by changing the plasma number density, collision …