Engineering Commons^™

Performance Of Nevada’S Aggregates In Alkali-Aggregate Reactivity Of Portland Cement Concrete, Mohammad Shahidul Islam

UNLV Theses, Dissertations, Professional Papers, and Capstones

Alkali-aggregate reaction (AAR) is a form of distress that occurs in concrete and results in serviceability problems, cracks, spalling, and other deterioration mechanisms. There are two categories of AAR, namely, alkali-silica reaction (ASR) and alkali-carbonate reaction (ACR). Alkali-silica reaction is one of the most recognized deleterious phenomena in concrete, and has been a major concern since its discovery in the 1940s. The reaction which occurs between reactive silica or silicates present in some aggregates and alkalis of Portland cement produces an alkali-silica gel that expands in the presence of moisture resulting in concrete cracks. ACR is also a chemical reaction …

An Exploratory Study On Energy Consumption Of Energy Star And Non-Energy Star Homes, Prajakta Kulkarni

UNLV Theses, Dissertations, Professional Papers, and Capstones

The reduction of energy consumption is one of the economic necessities in the United States due to depleting energy sources in the world. The construction industry is stepping forward to reduce the energy consumption of buildings by efficient designs or by constructing buildings with energy efficient materials and features. In 1992, the U.S. Environmental Protection Agency (EPA) and Department of Energy (DOE) introduced the Energy Star Program to promote energy efficient products with the same or improved services. According to the EPA, Energy Star homes, which use these products, will consume 20 to 30 percent less energy than non-Energy Star …

Assessment Of Impacts To Hydroclimatology And River Operations Due To Climate Change Over The Colorado River Basin, William Paul Miller

UNLV Theses, Dissertations, Professional Papers, and Capstones

This dissertation investigated the impacts of climate change to the hydroclimatology and river and reservoir management operations within the Colorado River Basin. Preliminary research indicated observed warming trends throughout the Colorado River Basin and corresponding seasonal trends to the magnitude and timing of runoff in the Colorado River Basin. Subsequent research investigated the changing character of precipitation and corresponding impacts to streamflow over the Colorado River Basin. Analysis of snowpack telemetry (SNOTEL) stations over the American West and Colorado River Basin indicated decreasing trends in annual snowpack, often at least at the 95% confidence interval. A shorter snowpack season was …

Ion-Exchange (Ix): Arsenic And Chromium Removal From Brines And Removal Of Inorganic Contaminants By Specialty Resins, Behrang Pakzadeh

UNLV Theses, Dissertations, Professional Papers, and Capstones

Although ion exchange is highly efficient in removing inorganic contaminants, similar to other water treatment technologies, ion exchange has some drawbacks that need to be studied further. Three issues related to drawbacks of ion-exchange resins in water treatment were addressed in this research. The first issue was the influence of anionic inorganic co-contaminants including nitrate, Cr(VI), Se(VI), and As(V) on the performances of nitrate and perchlorate specialty (selective) resins in water treatment. It was found that nitrate can be removed from waters using perchlorate specialty resins, but the resin is poorly regenerated. Perchlorate was not easily removed from either nitrate …

Flow Rate Measurement In A High Temperature, Radioactive, And Corrosive Environment, Taleb Moazzeni

UNLV Theses, Dissertations, Professional Papers, and Capstones

Accurate measurement of coolant flow rate is essential for determining the maximum power required by the nuclear plant operation and critical for monitoring its operation safety. However, no practical off-the-shelf flowmeter is available to satisfy all the pressing multidimensional operation requirements (i. e., high temperature, high irradiation, and high corrosion). This work thus deals with the development of a new flowmeter for nuclear power plant/reactor process-monitoring and real time analysis; this proposed flowmeter shall be able to continuously conduct robust measurements under extremely harsh environment with high irradiation, high pressure, high temperature and corrosive media. We investigate a transit-time based …

Evaluation Of Safety Impact Of Access Management In Urban Areas, Xuecai Xu

UNLV Theses, Dissertations, Professional Papers, and Capstones

The access provided by streets and highways to adjacent lands are managed by controlling the spacings between the access points including signals, driveways, and media openings on mid-block segments, and setting the limit on the corner clearances around intersections. There have been studies on evaluating the impact of access management techniques on safety and mobility in urban areas. Samples of mid-block segments and intersections can be collected from selected arterials. Because the mid-block segments or intersections in the same arterials share the same missing information, safety and mobility on them show unique features that should be taken into account when …

Design Of Adaptive Collective Foraging In Swarm Robotic Systems, Hanyi Dai

Dissertations

Inspired by the collective behavior observed in biological colonies, swarm robotics is a new approach to design a distributed control algorithm in order to coordinate a group of simple robots performing a complex group task. With only limited computation and communication ability of individual robots, one of the challenges in designing such multi-robotic systems is to understand the effect of individual robots behavior on the group performance. This thesis dedicates the research to designing a set of local interaction and adaptation rule for individual robots so that optimized collective foraging performance can be achieved at group level.

The research starts …

Modeling The Momentum And Mass Transfer Within A Micro-Scale Polymer Electrolyte Membrane Fuel Cell For Flows Within The Slip Flow Regime, Sean Tamarun Goudy

Dissertations

Polymer Electrolyte Membrane (PEM) fuel cell systems are heterogeneous catalytic systems. Although there are many computational models that describe the behavior of PEM fuel cells, few simulate the catalyst surface concentration of reactant gases at the catalyst layer-membrane layer inteface. Most PEM fuel cell models make no distinction between the bulk concentration of reactants and the catalyst surface concentration of reactants. It is the surface concentration that is key when studying PEM fuel cell systems: the reactions occur at the surface of the catalyst.

In addition, few model the dynamics within the non-continuum flow region near the solid surfaces of …

Optimum Failure Truncated Testing Strategies, Erik Kostandyan

Dissertations

Accumulated fatigue damage on mechanical components due to random stress loads eventually causes failure. Therefore products with lower failure rates are more desirable. Testing mechanical components for their intended purpose under predetermined working conditions is a common practice used by industries to prevent failures. Fatigue tests are categorized as Time Truncated or Failure Truncated, known in the literature as Type I and Type II tests, respectively. In failure truncated tests, the mechanical components are tested until the desired number of results is obtained. The parameters of a typical failure truncated test include the capacity of the test facility, the actual …

Optimizing Green Sand Properties Of Fluidized Sand From Aeration And Developing New Green Sand Testing Technique, Ananda Mani Paudel

Dissertations

Aeration sand filling is a new molding technique in foundry. Using this technique, sand with smooth flow can be filled in any orientation and shape using low-pressure air. This is not possible by conventional gravity and high-pressure blow filling techniques. Aeration was introduced as an energy-efficient and environmentally- friendly sand molding technique. In addition, aeration has its niche on quality of molds it could produce. Friability, one of the crucial green properties for the quality mold was significantly low in aeration in comparison to the gravity and high-pressure blow filling. The fluidization action in aeration acted upon the sand clay …

Electrospun Scaffolds For Directed Pancreatic Differentiation Of Human Ips Cells, Karl Sonntag

Biological and Agricultural Engineering Undergraduate Honors Theses

In this work, an electrospinning device for fabricating three-dimensional scaffolds was constructed. The device can be used to produce tissue engineered scaffolds electrospun for directing the differentiation of human induced pluripotent stem (iPS) cells into glucose-responsive, insulin-secreting cells for diabetes treatment. Electrospinning utilizes high electrical charge to generate nanofibers from polymers dissolved in solution. A standard setup for such a device includes a high-voltage power source, a syringe pump, and a grounded collector. The process works by dissolving the polymer in a volatile solvent, and filling a syringe with the polymer/solvent mixture. Next, the syringe is locked into place in …

Exploring Managed Nand Media Endurance, Mark G. Jurenka

Boise State University Theses and Dissertations

Flash memory can be found in media players, cameras, cell phones and portable storage. These consumer items have universally compatible storage devices. However, what is their longevity and what is the long-term data retention reliability? This thesis will explore and attempt to answer these questions. Predicting accurate endurance ratings and long-term storage reliability is problematic; a storage card in a cell phone will simply wear differently if used for personal computer backup. Advertised longevity ratings can also be ambiguous, specified in a number of years of ‘typical’ and ‘average’ use.

This thesis begins by exploring the operation of flash technology …

Energy And Nutrient Recovery From Anaerobic Treatment Of Organic Wastes, Christian-Dominik Henrich

All Dissertations

The objective of the research was to develop a complete systems design and predictive model framework of a series of linked processes capable of providing treatment of landfill leachate while simultaneously recovering nutrients and bioenergy from the waste inputs. This proposed process includes an 'Ammonia Recovery Process' (ARP) consisting of: 1) ammonia de-sorption requiring leachate pH adjustment with lime or sodium hydroxide addition followed by, 2) ammonia re-absorption into a 6-molar sulfuric acid spray-tower followed by, 3) biological activated sludge treatment of soluble organic residuals (BOD) followed by, 4) high-rate algal post-treatment and finally, 5) an optional anaerobic digestion process …

Grain Boundary Premelting And Activated Sintering In Binary Refractory Alloys, Xiaomeng Shi

All Dissertations

Quasi-liquid intergranular film (IGF) which has been widely observed in ceramic systems can persist into sub-solidus region whereby an analogy to Grain boundary (GB) premelting can be made.
In this work, a grain boundary (GB) premelting/prewetting model in a metallic system was firstly built based on the Benedictus' model and computational thermodynamics, predicting that GB disordering can start at 60-85% of the bulk solidus temperatures in selected systems. This model quantitatively explains the long-standing mystery of subsolidus activated sintering in W-Pd, W-Ni, W-Co, W-Fe and W-Cu, and it has broad applications for understanding GB-controlled transport kinetics and physical properties. Furthermore, …

Effects Of Reamer-Femoral Component Offset On Cement Mantle Penetration In Hip Resurfacing Arthroplasty, Mark Lloyd Paulick

Master's Theses

Hip resurfacing arthroplasty has changed the treatment of end stage arthritis without severe deformity for young, active adults. Presently, there are varying clinical approaches to implant design selection and cementation techniques. The purpose of this project is to determine what amount of reamer-femoral component offset allows for the best cement penetration into the femoral head.

Rapid prototyped femoral component models were produced with reamer femoral component offsets of 0.0 mm, 0.5 mm, and 1.0 mm. After implantation onto models of reamed femoral heads made from high-density open-cell reticulated carbon foam, cement penetration was assessed from cross-sections of the foam-implant unit. …

Coping With The Curse Of Dimensionality By Combining Linear Programming And Reinforcement Learning, Scott H. Burton

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Reinforcement learning techniques offer a very powerful method of finding solutions in unpredictable problem environments where human supervision is not possible. However, in many real world situations, the state space needed to represent the solutions becomes so large that using these methods becomes infeasible. Often the vast majority of these states are not valuable in finding the optimal solution. This work introduces a novel method of using linear programming to identify and represent the small area of the state space that is most likely to lead to a near-optimal solution, significantly reducing the memory requirements and time needed to arrive …

Implementation Of A Coal Level Sensing And Control System Comparing Range Sensor Modalities, Ralph Lee Taylor

Electrical Engineering Theses

A coal-fired power plant typically has silos, bunkers or stockpiles in which the fuel is placed for storage purposes. Real-time feedback sensors are utilized to sense the coal height so data can be sent to downstream systems for further processing. These systems are required to accurately sense the height of coal within the bunker or stockpile. The range information is then fed in a real-time fashion to a control system. Inaccurate measurements can result in severe environment and safety consequences. The coal-fired power plant application is especially daunting due to the particularly harsh operating conditions and reliability requirements. There are …

The Integration Of Smart Meters Into Electrical Grids To Ensure Maximum Benefit For Consumers, Generators And Network Operators., Tom Bean, John Mcgrory

Dissertations

The term “smart metering” has been used in many project descriptions and publications produced by utility companies (e.g. gas, water and electricity), conference papers and journal papers, but the true meaning of the term has been fudged. Does smart metering signify rapid recording of data (i.e. data logger) or does it give totals (e.g. maximum, minimum and average), as neither of these are truly “Smart” or “Intelligent” virtues in themselves, or is there some additional role that needs to be explored. This dissertation examines the “smart metering” idiom jointly from energy supplier, grid manager and consumer perspectives and formulates a …

Evaluation Of Quasi-Static Indentation Damage In Aluminum Honeycomb Core - Graphite/Epoxy Sandwich Structures, David Eisenberg

Renée Crown University Honors Thesis Projects - All

Sandwich composites utilize a low density core and relatively stiff face sheets. These structures are ideal for applications that require high compressive strength, high bending stiffness, and very low weight such as aerospace vehicles. However, one problem with sandwich composites is their susceptibility to low velocity impact damage. Low velocity impacts result in both external damage, in the form of dents, and internal damage, in the form of core crushing, face sheet delaminations (two adjacent plies separating from one another), fiber fractures and matrix cracks. In general, it is assumed that visibly evident damage will be repaired. Barely visible impact …

Liquid Crystalline Elastomers: Effects Of Substrate Anisotropy On Cell Behavior, Christine Depompeo

Renée Crown University Honors Thesis Projects - All

One of the major challenges in tissue engineering today is inducing organization at the cellular level in vitro. Most biological tissues exhibit anisotropic behavior. They perform differently and have different mechanical properties in different directions. This environment is difficult to mimic with traditional cell culturing methods. The development of anisotropic cell substrates may have the potential to encourage the organization required at the cellular level to induce in vitro tissue formation, an exciting prospect for the advancement of the field of tissue engineering.

It is well known that liquid crystalline elastomers (LCEs) are highly organized polymers with temperature-dependent properties. …

Production Of Multiwall Carbon Nanotuse For Alcohol Sensor Application., Ebtehal Saleh Alshaqaq

Student Works (2010-2019)

Multiwall carbon nanotube/polyethylene oxide (PEO), multiwall carbon nanoube/polyvinyl alcohol(PVA) and multiwall carbon nanotube/ polyvinyl alcohol(PVA)/zinc oxide(ZnO) have been tested as chemical sensors and detailed study on the effect of different gas concentration and material properties on gas sensitivity is presented. Initial composites were prepared by a simple solution casting and characterized by x-ray diffraction for ZnO, Fourier transform infra-red spectroscopy (FTIR) and scanning electron microscopy (SEM) to demonstrate crystallite size of ZnO, the morphology and surface area respectively. On the other hand, MWCNT/PEO , MWCNT/PVA , MWCNT/PVA/ZnO were prepared with different loading MWCNT and ZnO. The chemical sensing properties of …

Vibrational Frequencies Of Magnetic Random Access Memory Materials., Lee Li Ling

Student Works (2010-2019)

The advantages of MRAM are so overwhelming which acts as motivation for scientist in further investigation for better read and write operation. The types of materials used are closely related to the cell performance in forming the ferromagnetic layers. Thus,the vibrational frequencies of the MRAM materials are of interest. Clusters for the two types of combinations, FexNiy and FexCoyBz are built. Subsequently, vibrational frequencies of each cluster are calculated theoretically from the first principles. The secular determinant is large when the number of electrons in a cluster is large. For the simplest combination of Fe-Ni cluster, (atomic number of an …

Oscillation Phenomenon Of The New York Canal At The I-84 Overpass In Boise, Idaho, Erik W. Robison

All Graduate Plan B and other Reports, Spring 1920 to Spring 2023

As part of the Idaho Transportation department's GARVEE program, the 1-84 bridge structure at the New York Canal in Boise, Idaho, was widened in 2009. During the 2009 irrigation season, oscillation patterns were noticed at the bridge structure which resulted in erosion damage to the banks of the canal. After ITD consulted with Horrocks Engineers, a contract was established with the Utah Water Research Laboratory at Utah State University to construct a Froude scale model of the structure. The purpose of the model was to determine the cause of the oscillations, and develop an effective method to eliminate them. The …

Development Of A Structural Index As An Integral Part Of The Overall Pavement Quality In The Indot Pms, William Frederick Flora, Ghim Ping (Raymond) Ong, Kumares C. Sinha

JTRP Technical Reports

No abstract provided.

Hidra: Hierarchical Inter-Domain Routing Architecture, Bryan Clevenger

Master's Theses

As the Internet continues to expand, the global default-free zone (DFZ) forwarding table has begun to grow faster than hardware can economically keep pace with. Various policies are in place to mitigate this growth rate, but current projections indicate policy alone is inadequate. As such, a number of technical solutions have been proposed. This work builds on many of these proposed solutions, and furthers the debate surrounding the resolution to this problem. It discusses several design decisions necessary to any proposed solution, and based on these tradeoffs it proposes a Hierarchical Inter-Domain Routing Architecture - HIDRA, a comprehensive architecture with …

Design, Construction And Evaluation Of Side Mount Truck Tool Boxes And Fuel Transfer Tank, Trey Avila

BioResource and Agricultural Engineering

This senior project discusses the design, construction, evaluation and cost analysis of side mounted truck tool boxes and a fuel transfer tank. The need for the boxes arose when specific tools and extra fuel had to be carried at all times. The objective was to build a set of tool boxes and a fuel transfer tank to fit a Ford short bed and still have a four foot wide area in between the boxes. Results show objective being met, but cost analysis shows that it’s not feasible for low scale production.

Affordable Lightweight High Performance Concrete (Alwhpc): Expanding The Envelope Of Concrete Mix Design, Kevin J. Simons

Department of Construction Engineering and Management: Dissertations, Theses, and Student Research

One way to reduce excess material would be to lighten the load on a structure with the use of affordable lightweight high performance concrete (ALWHPC). Most or all lightweight high performance concrete mixes used today include lightweight aggregates as the coarse aggregate and sand for the fine aggregate. ALWHPC mix designs contain all lightweight aggregates and cementitious materials that are readily available throughout the United States. Instead of 115 – 120 pcf, ALWHPC mix designs range from 88 – 100 pcf and strengths from 2,700 – 8,700 psi compressive strength. This research will explore the use of local lightweight aggregates …

Channel Equalization And Symbol Detection For Single-Carrier Mimo Systems In The Presence Of Multiple Carrier Frequency Offsets, Jian Zhang, Yahong Rosa Zheng, Chengshan Xiao, Khaled Ben Letaief

Electrical and Computer Engineering Faculty Research & Creative Works

A new frequency-domain channel equalization and symbol detection scheme is proposed for multiple-input multiple-output (MIMO) single-carrier broadband wireless systems in the presence of severely frequency-selective channel fading and multiple unknown carrier-frequency offsets (CFOs). Multiple CFOs cause severe phase distortion in the equalized data for large block lengths and/or constellation sizes, thus yielding poor detection performance. Instead of explicitly estimating the CFOs and then compensating them, the proposed scheme estimates the rotated phases (not frequencies) caused by multiple unknown CFOs and then removes the phase rotations from the equalized data before symbol detection. the estimation accuracy of the phase rotation is …

Signal Integrity Design For High-Speed Digital Circuits: Progress And Directions, Jun Fan, Xiaoning Ye, Jingook Kim, Bruce Archambeault, Antonio Orlandi

Electrical and Computer Engineering Faculty Research & Creative Works

This paper reviews recent progress and future directions of signal integrity design for high-speed digital circuits, focusing on four areas: signal propagation on transmission lines, discontinuity modeling and characterization, measurement techniques, and link-path design and analysis. © 2006 IEEE.

Systematic Microwave Network Analysis For Multilayer Printed Circuit Boards With Vias And Decoupling Capacitors, Yao Jiang Zhang, Zaw Zaw Oo, Xing Chang Wei, En Xiao Liu, Jun Fan, Er Ping Li

Electrical and Computer Engineering Faculty Research & Creative Works

An efficient microwave network method is proposed for signal and power integrity analysis of a multilayer printed circuit board with multiple vias and decoupling capacitors. the multilayer parallel plate structure is described as a cascaded microwave network. the admittance matrix of a single plate pair with ports defined in via holes both on top and bottom plates is obtained through the intrinsic via circuit model and impedance matrix between two plates. a recursive algorithm is provided to obtain the combined admittance matrix of two layers of plate pair coupled through via holes on a common plate. Decoupling capacitors are naturally …