Engineering Commons^™

Flow Shop Scheduling For Energy Efficient Manufacturing, Hao Zhang

Open Access Dissertations

A large number of new peaking power plants with their associated auxiliary equipment are installed to meet the growing peak demand every year. However, 10% utility capacity is used for only 1%~2% of the hours in a year. Thus, to meet the demand and supply balance through increasing the infrastructure investments only on the supply side is not economical. Alternatively, demand-side management might cut the cost of maintaining this balance via offering consumers incentives to manage their consumption in response to the price signals.

Time-varying electricity rate is a demand-side management scheme. Under the time-varying electricity rate, the electricity price …

Reactions Of Graphene Oxide And Buckminsterfullerene In The Aquatic Environment, Yingcan Zhao

Open Access Dissertations

Due to unique physical and chemical properties, carbon-based nanomaterials, including C60 and graphene oxide, now being used in an increasing number of applications. Considering their widespread use, nanoparticles will inevitably find their way to the natural environment. However, their environmental fate and transport have not been intensively explored, resulting in a general lack of knowledge regarding their risk assessment and life cycle exposure concentrations. To this end, this study has investigated: (i) the photo mineralization of aqu/nC60 clusters under photo irradiation, and (ii) environmental transformation of graphene oxide in the aquatic environment. This study shows that CO2 was produced from …

Flow Shop Scheduling For Energy Efficient Manufacturing, Hao Zhang

Open Access Dissertations

A large number of new peaking power plants with their associated auxiliary equipment are installed to meet the growing peak demand every year. However, 10% utility capacity is used for only 1%~2% of the hours in a year. Thus, to meet the demand and supply balance through increasing the infrastructure investments only on the supply side is not economical. Alternatively, demand-side management might cut the cost of maintaining this balance via offering consumers incentives to manage their consumption in response to the price signals.

Time-varying electricity rate is a demand-side management scheme. Under the time-varying electricity rate, the electricity price …

Development And Initial Validation Of A Surgical Instrument For In Situ Mechanical Characterization Of Surgical Mesh-Tissue Composites, Jorge Ivan Hernandez Sanchez

All Theses

Approximately 5 million Americans have an abdominal wall hernia, and over 700,000 undergo surgical procedures every year to treat them. Surgical procedures have evolved with the goal of preventing recurrences, leading to the current gold standard of treatment: hernia repair with mesh. Hernia repair with mesh consists on augmenting the weakened abdominal wall by implanting a synthetic or biological mesh. Although the adoption of hernia repair with mesh has improved outcomes, recurrence from primary repair procedures with large incisions (>10 cm) remains an alarming 32%.

The wide variety of implanted surgical mesh (materials, structure) and surgical variability (attachment method, …

Robust Algorithms For Estimating Vehicle Movement From Motion Sensors Within Smartphones, Ilyas Ustun

Computational Modeling & Simulation Engineering Theses & Dissertations

Building sustainable traffic control solutions for urban streets (e.g., eco-friendly signal control) and highways requires effective and reliable sensing capabilities for monitoring traffic flow conditions so that both the temporal and spatial extents of congestion are observed. This would enable optimal control strategies to be implemented for maximizing efficiency and for minimizing the environmental impacts of traffic. Various types of traffic detection systems, such as inductive loops, radar, and cameras have been used for these purposes. However, these systems are limited, both in scope and in time. Using GPS as an alternative method is not always viable because of problems …

Delay-Independent Stability Analysis Of Linear Time-Delay Systems Based On Frequency, Xianwei Li, Huijun Gao, Keqin Gu

SIUE Faculty Research, Scholarship, and Creative Activity

This paper studies strong delay-independent stability of linear time-invariant systems. It is known that delay-independent stability of time-delay systems is equivalent to some frequency-dependent linear matrix inequalities. To reduce or eliminate conservatism of stability criteria, the frequency domain is discretized into several sub-intervals, and piecewise constant Lyapunov matrices are employed to analyze the frequency-dependent stability condition. Applying the generalized Kalman–Yakubovich–Popov lemma, new necessary and sufficient criteria are then obtained for strong delay-independent stability of systems with a single delay. The effectiveness of the proposed method is illustrated by a numerical example.

Total Temperature Measurement At Pulse Detonation Engine Exhaust, Ninad Ramesh Kawle

Mechanical and Aerospace Engineering Theses - Archive

Pulse detonation engines (PDEs) are being studied in recent years as a potential means of power production. In PDEs, a supersonically travelling detonation wave traverses through the detonation tube. Total temperature of the exhaust of the PDE is not a well-known parameter. The objective of the research was to calibrate and employ miniature type E thermocouples for exhaust temperature measurement of the PDE. The probe making process along with the calibration techniques for AWG 20, AWG 24 and AWG 50 thermocouples are discussed at length. The time constants for thermocouples were determined. Reactive mixture containing hydrogen and oxygen was used …

Analysis Of The Gauss-Bingham Distribution For Attitude Uncertainty Propagation, Jacob E. Darling, Kyle J. Demars

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Attitude uncertainty quantification typically requires a small angle assumption, and thus an inherent small uncertainty assumption, to be made. This small angle assumption can be eliminated by employing the Bingham distribution to represent the attitude uncertainty in the attitude quaternion directly. Moreover, an extension to the Bingham distribution, termed the Gauss-Bingham distribution, can be used to represent correlated attitude quaternion and angular velocity uncertainty to enable attitude uncertainty propagation. In order to evaluate the potential accuracy gain using the Gauss-Bingham distribution for attitude uncertainty quantification, the Gauss-Bingham distribution method for attitude uncertainty propagation is compared to the propagation step of …

Distributed Inference And Learning With Byzantine Data, Bhavya Kailkhura

Dissertations - ALL

We are living in an increasingly networked world with sensing networks of varying shapes and sizes: the network often comprises of several tiny devices (or nodes) communicating with each other via different topologies. To make the problem even more complicated, the nodes in the network can be unreliable due to a variety of reasons: noise, faults and attacks, thus, providing

corrupted data. Although the area of statistical inference has been an active area of research in the

past, distributed learning and inference in a networked setup with potentially unreliable components

has only gained attention recently. The emergence of big and …

Molecular Dynamics Study Of Solid-Liquid Heat Transfer And Passive Liquid Flow, Sumith Yesudasan Daisy

Dissertations - ALL

High heat flux removal is a challenging problem in boilers, electronics cooling, concentrated photovoltaic and other power conversion devices. Heat transfer by phase change is one of the most efficient mechanisms for removing heat from a solid surface. Futuristic electronic devices are expected to generate more than 1000 W/cm2 of heat. Despite the advancements in microscale and nanoscale manufacturing, the maximum passive heat flux removal has been ~300 W/cm2 in pool boiling. Such limitations can be overcome by developing nanoscale thin-film evaporation based devices, which however require a better understanding of surface interactions and liquid vapor phase change process. Evaporation …

Systematic Discovery Of Android Customization Hazards, Yousra Aafer

Dissertations - ALL

The open nature of Android ecosystem has naturally laid the foundation for a highly fragmented operating system. In fact, the official AOSP versions have been aggressively customized into thousands of system images by everyone in the customization chain, such as device manufacturers, vendors, carriers, etc. If not well thought-out, the customization process could result in serious security problems. This dissertation performs a systematic investigation of Android customization’ inconsistencies with regards to security aspects at various Android layers.

It brings to light new vulnerabilities, never investigated before, caused by the under-regulated and complex Android customization. It first describes a novel vulnerability …

Cognitive Radio Systems: Performance Analysis And Optimal Resource Allocation, Gozde Ozcan

Dissertations - ALL

Rapid growth in the use of wireless services coupled with inefficient utilization of scarce spectrum resources has led to the analysis and development of cognitive radio systems. Cognitive radio systems provide dynamic and more efficient utilization of the available spectrum by allowing unlicensed users (i.e., cognitive or secondary users) to access the frequency bands allocated to the licensed users (i.e., primary users) without causing harmful interference to the primary user transmissions. The central goal of this thesis is to

conduct a performance analysis and obtain throughput- and energy-efficient optimal resource allocation strategies for cognitive radio systems. Cognitive radio systems, which …

Contributions On Theory And Practice For Multi-Mission Wireless Systems, Yu Zhao

Dissertations - ALL

The field of wireless systems has long been an active research area with various applications. Recently much attention has been given to multi-mission wireless systems that combine capabilities including information sensing, data processing, energy harvesting as well as the traditional data communication. This dissertation describes our endeavor in addressing some of the research challenges in multi-mission wireless systems, including the development of fundamental limits of such multi-mission wireless systems and effective technologies for improved performance.

The first challenge addressed in this dissertation is how to handle interference, which is encountered in almost all wireless systems involving multiple nodes, an attribute …

Resource Allocation For Interference Management In Wireless Networks, Raghed El Bardan

Dissertations - ALL

Interference in wireless networks is a major problem that impacts system performance quite substantially. Combined with the fact that the spectrum is limited and scarce, the performance and reliability of wireless systems significantly deteriorates and, hence, communication sessions are put at the risk of failure. In an attempt to make transmissions resilient to interference and, accordingly, design robust wireless systems, a diverse set of interference mitigation techniques are investigated in this dissertation.

Depending on the rationale motivating the interfering node, interference can be divided into two categories, communication and jamming. For communication interference such as the interference created by legacy …

Method Of Characteristics Verification Of Inverse Frequency Model Of Turbulent Pipe Flow Transients, Mohammad Saifullah Mohammad Zafar Shaikh

Mechanical and Aerospace Engineering Theses - Archive

Pressure transients in pipes with turbulent flow have classically been simulated using numerical techniques such as the method of characteristics. An alternative method utilizing an inverse frequency algorithm has recently been introduced for smooth pipe and determined to be computationally fast compared to the method of characteristics and in some cases more accurate. In addition, comparisons with experimental water hammer data has verified that the inverse frequency method is accurate out to Reynolds numbers of 15,800. This thesis investigates a comparison or the inverse frequency and method of characteristics methods for Reynolds numbers out to 200,000 for smooth pipes.

A Novel Stress Analysis Method For Laminated Composite Stiffener With Asymmetric Z-Section Under Mechanical And Thermal Loading Conditions, Sidhant Singh

Mechanical and Aerospace Engineering Theses - Archive

Composites structures are being used as load carrying members in latest aircrafts and performance automobiles, the design validation for such structures can be a time consuming and expensive process, if done by testing. Validation of a structure by analysis saves time and money for a design process and validation by analysis can be done by comparing the analytical solution with the finite element analysis of the structure, which requires availability of analytical expressions for every cross-sectional arrangement of the structural members. This research focuses on stress analysis of laminated composite stiffener with asymmetric Z-sections, where closed form analytical expressions are …

Finite Element Analysis For Astm C-76 Reinforced Concrete Pipes With Reduced Steel Cage, Amin Darabnoush Tehrani

Civil Engineering Theses - Archive

Reinforced concrete pipes (RCP) are composite pipes which have been widely used in the industry for more than ten decades. They are generally used for sewerage, water drainage, and industrial waste water. There are two methods for designing the RCP so that it will bear the soil weight and the live load on it: Indirect design (ID) and direct design (DD) methods. ASTM C76 (1) classifies pipes into five categories. The five categories of pipes have been classified in order of ascending pipe diameter with their required load and reinforcement’s area. Typically, there are two reinforcement types: circumferential and longitudinal. …

A Lognormal Reliability Design Model, Edward Osakue, Lucky Anetor

Faculty Publications

It is well known that design loads vary randomly during equipment operations. Similarly, material properties such as yield strength, tensile strength, fatigue strength, etc. are random variables. Design analytical models are approximations of reality and failure mode models are also approximations. Consequently, design solutions are not exact. Practical design must therefore, consider the random nature and statistical variability of design parameters. Reliability-based design models are developed to provide practical design methods. This paper develops a lognormal reliability-based design model that can be coded in Excel Spreedsheet. Two design examples are considered in demonstrating the application of the formulated model. In …

Transportation System And Its Association With Human Health – A Review And Modeling Approach, Fnu Zahed

Masters Theses

Transportation systems constitute of infrastructure, commute modes, land use and other policies. The purpose of transportation is to provide easy access to goods and services. While attaining this purpose, impacts of transportation on human health and well-being have been ignored to some extent. Recently, studies have begun analyzing the impact of transportation systems on quality of life and health disparities. While many studies have discussed the impact of the transportation system on individual factors from health, a very limited number of studies have focused on the impact of multiple factors associated with multiple morbidity and mortality forms. The focus of …

Torsional Strengthening Of Reinforced Concrete Beams Using Cfrp Composites, Ranj Rafeeq

Dissertations and Theses

Few decades ago, there were no guidelines for torsion design of reinforced concrete (RC) beams. Hence, many existing beams in older buildings have a lack of adequate torsional strength since they were not properly designed for torsion. One way to regain/rehabilitate adequate torsional strength is through application of externally bonded carbon fiber reinforced polymers (CFRP). To date, American Concrete Institute (ACI) code, as well as other building codes, do not have recommendations or provisions for strengthening RC beams for torsion using fiber-reinforced polymer (FRP) composites due to the inexistence of conclusive experimental and analytical data. Of the very limited works …

Nanomaterials For Solar Distillation Technology, Jack Warren Stoddard Cheney

UNLV Theses, Dissertations, Professional Papers, and Capstones

Water is the most important resource for mankind. Yet, 97% of the earth’s surface water is seawater in the oceans and only 3% is fresh water in ground water. Therefore, different kinds of water desalination and treatment technologies have been developed, and water distillation is a basic process of evaporating water in order to leave behind impurities such as minerals, pollutants, and other contaminants. Although distillation is known as an effective water treatment process that removes many kinds of bacteria and inorganic chemicals and heavy metals, a large amount of conventional energy and non-renewable resources are consumed for this process. …

The Validation And Verification Of Les Modeling Using Kiva, David Fyda

UNLV Theses, Dissertations, Professional Papers, and Capstones

In recent years, the use of large-eddy simulation (LES) has grown into new research methods. LES is preferred when compared to Reynold’s Averaged Navier Stokes (RANS), which separates velocity components into steady and fluctuating components. While RANS is relatively easy to implement, it does not fully resolve the range of turbulence eddies and has limitations that make it inaccurate in many practical circumstances. Direct numerical simulation, DNS, fully resolves all turbulent eddies to the smallest grid scale, but requires an extremely fine grid. This makes it computationally impractical to use as the computational power required to solve even the simplest …

Design And Implementation Of Benes/Clos On-Chip Interconnection Networks, Yikun Jiang

UNLV Theses, Dissertations, Professional Papers, and Capstones

Networks-on-Chip (NoCs) have emerged as the key on-chip communication architecture for multiprocessor systems-on-chip and chip multiprocessors. Single-hop non-blocking networks have the advantage of providing uniform latency and throughput, which is important for cachecoherent NoC systems. Existing work shows that Benes networks have much lower transistor count and smaller circuit area but longer delay than crossbars. To reduce the delay, we propose to design the Clos network built with larger size switches. Using less than half number of stages than the Benes network, the Clos network with 4x4 switches can significantly reduce the delay. This dissertation focuses on designing high performance …

Characterization Of Impact Properties Of Forged, Layered, And Additive Manufactured Titanium Alloy, Melissa Kathryn Matthes

UNLV Theses, Dissertations, Professional Papers, and Capstones

New additive manufactured (AM) materials have the potential of optimizing the geometry and microstructure of complex components to enhance their structural integrity while creating them quickly. However, the behavior of AM materials under extreme dynamic loading conditions is not fully understood. This is especially important in many applications. For example, spacecraft components may be impacted by micrometeorites at hyper velocities of multiple kilometers per second, inducing extreme dynamic loading.

One type of AM material is created by melting and solidifying metal along a specified path. Depending on the geometry, additional streams will be deposited side-by-side. This process affects the microstructure …

Design, Fabrication And Testing Of Monolithic Low-Power Passive Sigma-Delta Analog-To-Digital Converters, Angsuman Roy

UNLV Theses, Dissertations, Professional Papers, and Capstones

Analog-to-digital converters are critically important in electronic systems. The

difficulty in meeting high performance parameters increases as integrated circuit design

process technologies advance into the deep nanometer region. Sigma-delta analog-todigital

converters are an attractive option to fulfill many data converter requirements.

These data converters offer high performance while relaxing requirements on the precision

of components within an integrated circuit. Despite this, the active integrators found within

sigma-delta analog-to-digital converters present two main challenges. These challenges are

the power consumption of the active amplifier and achieving gain-bandwidth necessary for

sigma-delta data converters in deep nanometer process technologies. Both of these

challenges …

Forcing Cesium Into Higher Oxidation States Via Useful Hard X-Ray Induced Chemistry At Extreme Conditions, Daniel Thomas Sneed

UNLV Theses, Dissertations, Professional Papers, and Capstones

Recent theoretical work published in Nature Chemistry postulates the existence of cesium in high oxidation states when bonding with fluorine. It is thus predicted to behave as a p-block element (such as xenon) at pressures above 5 GPa. At these pressures, fluorine atoms may bond with the inner p-shell electrons forming CsFn, where n may vary from 2 up to 6; thus the oxidation state of Cs may change up to 6+. My research focused on physically synthesizing these compounds and to verify that, given the right conditions, bonding doesn't only occur with valence electrons, but with the inner p-shell …

Ionic Polymer-Metal Composite Actuators Based On Nafion Blends With Functional Polymers, Jungsoo Nam

UNLV Theses, Dissertations, Professional Papers, and Capstones

Ionic polymer metal composites (IPMCs) have been an attractive research subject for use in underwater robotic applications, biomedical and biomimetic application owing to their great potential as actuators, artificial muscles, and more. IPMC is synthetic composite nanomaterial of ion exchange membranes and metal electrode. Although both components are important, the properties of ion exchange membranes should be emphasized since it is responsible of the path for the mobile ions to migrate when voltage is applied to exhibit deformation. Most of the researches that have been done on IPMCs used commercially available Nafion as their ion exchange membranes. However, its high …

Visualization Of Dropwise Condensation On Vertical Plate And Horizontal Tube Geometry, Blake Naccarato

UNLV Theses, Dissertations, Professional Papers, and Capstones

A droplet detection method has been developed to measure the distribution of droplet sizes on a flat plate under dropwise condensation. Dropwise condensation heat transfer may be modeled by combining an expression for the single droplet heat transfer rate with the droplet size distribution. The ability to measure this distribution is integral to the validation of such models. An example study is undertaken in which heat flux is obtained for a given surface treatment by implementing such a model and measuring the droplet size distribution. These results are compared with the heat flux measured by internal coolant temperature monitoring for …

Thermoelectric Half-Heuslers: Synthesis, Processing, And Performance, Joseph Robert Croteau

Boise State University Theses and Dissertations

Thermoelectric half-Heusler compounds have potential to convert the heat wasted from industrial and transportation processes to useful electricity. Among the highest performing half-Heusler compounds are nano-structured bulk materials which have been arc-melted, pulverized into a nano-powder, and sintered by DC-hot press. High performing n- and p-type half-Heusler compounds with nominal composition of Hf_0.25Zr_0.75NiSn_0.99Sb_0.01 and Nb_0.75Ti_0.25FeSb, respectively, have been provided to us in both dense and powder form by our collaborators at the University of Houston. We consolidate these powders by SPS, refine these powders to improve both particle size …

A System For Monitoring And Managing Indoor Air Quality And Environmental Conditions, Ali Ibrahim

Boise State University Theses and Dissertations

The quality of indoor air depends on different types of pollutant sources existing in a semi-enclosed environment. The sources can be biological, chemical, or toxic pollutants. These sources can cause health issues and discomfort for occupants. One of the indicators of poor indoor air quality is Carbon Dioxide (CO₂). CO₂ can be used to indicate the indoor air exchange rate. The lack of air exchange means higher levels of CO₂. High levels of indoor particulates can also be an indication of poor air quality. Due to the lack of fresh air, air circulation, and air …