Engineering Commons^™

Development Of A Heart Rate Variability Measurement System Using Embedded Electronics, Naresh Kumar Velmurugan

Graduate Theses and Dissertations

Recent advances in embedded electronics have a remarkable influence on the health care system. One of the most important applications is to monitor the health care of the patients at anytime and anyplace. In the last two decades, many researchers have focused mainly on heart rate variability (HRV) measurements. Patient's heart rate variability should be continuously monitored to help them in case of emergency. Under these circumstances, patients are required to have a HRV measuring kit for a constant observation.

The proposed project focuses on the development of a heart rate variability measurement system with the use of embedded electronics. …

Optimizing Performance And Scalability On Hybrid Mpsocs, Hongyuan Ding

Graduate Theses and Dissertations

Hardware accelerators are capable of achieving significant performance improvement. But design- ing hardware accelerators lacks the flexibility and the productivity. Combining hardware accelerators with multiprocessor system-on-chip (MPSoC) is an alternative way to balance the flexibility, the productivity, and the performance. However, without appropriate programming model it is still a challenge to achieve parallelism on a hybrid (MPSoC) with with both general-purpose processors and dedicated accelerators. Besides, increasing computation demands with limited power budget require more energy-efficient design without performance degradation in embedded systems and mobile computing platforms. Reconfigurable computing with emerging storage technologies is an alternative to enable the optimization …

Disinfection Byproduct Formation Resulting From Settled, Filtered, And Finished Water Treated By Titanium Dioxide Photocatalysis, Brooke K. Mayer, Erin Daugherty, Morteza Abbaszadegan

Civil and Environmental Engineering Faculty Research and Publications

This study evaluated strategies targeting disinfection byproduct (DBP) mitigation using TiO₂ photocatalysis with varying influent water quality. A Purifics Photo-CAT Lab reactor was used to assess total trihalomethane (TTHM) and haloacetic acid (HAA) formation as a function of photocatalytic treatment using water from a conventional coagulation/flocculation/sedimentation process, granular activated carbon filtration, and a DBP hot spot in the water distribution system. Regardless of influent water quality, photocatalysis reduced DBP precursors; however, low-energy limited photocatalysis (m⁻³), exacerbated the production of TTHMs and HAA5s beyond initial levels. Accordingly, limited photocatalysis is not a suitable option when TTHMs and HAA5s …

Flex-16: A Large-Displacement Monolithic Compliant Rotational Hinge, Robert Mcintyre Fowler, Alex Maselli, Peter Pluimers, Spencer P. Magleby, Larry L. Howell

Faculty Publications

This paper describes the design, analysis, and testing of a large-displacement monolithic compliant rotational hinge, called the Flex-16. The Flex-16 achieves 90 of rotation from monolithic construction and is aimed for application as a compliant satellite deployment hinge. Five prototypes were fabricated from three different materials (polypropylene, titanium, and a carbon nanotube framework) on two different size scales (macro and micro). A parametric finite element model was created to rapidly analyze a variety of design identified during a configuration study. Prototypes were tested for their ability to reach 90 of rotation without failure or self collision, and for their nonlinear …

Flexural Strengthening Of One-Way Continuous Reinforced Concrete Slabs With Cutoffs In Sagging And Hogging Regions, Jafar Husni Alshawa.

Theses

Installation of cutouts in existing reinforced concrete (CR) floor slabs to accommodate utility services reduces the slab load capacity and ductility. This research examines the effectiveness of using near-surface-mounted (NSM) carbon fiber reinforced polymer (CFRP) reinforcement to improve the flexural response of continuous RC slabs with cutouts. The study comprised experimental testing and analytical modeling. A total of eleven two-span RC slabs strips, 400 x 125 x 3800mm each were tested. Test parameters included the location of the cutouts, and amount and distribution of the NSM-CFRP reinforcement between the sagging and hogging regions.

Installation of a cutout in the sagging …

Light Field Imaging Applied To Reacting And Microscopic Flows, Jonathon Remy Pendlebury

Theses and Dissertations

Light field imaging, specifically synthetic aperture (SA) refocusing is a method used to combine images from an array of cameras to generate a single image with a narrow depth of field that can be positioned arbitrarily throughout the volume under investigation. Creating a stack of narrow depth of field images at varying locations generates a focal stack that can be used to find the location of objects in three dimensions. SA refocusing is particularly useful when reconstructing particle fields that are then used to determine the movement of the fluid they are entrained in, and it can also be used …

A Further Look At Capacitors In Complex Arrangements, Kenneth V. Cartwright, Patrick Russell, Edit J. Kaminsky

Electrical Engineering Faculty Publications

Recently, a previous contributor showed how the delta-wye conversion may be applied to find the equivalent capacitance of five capacitors arranged in a bridge configuration. In fact, that contributor gave an algorithm for this purpose which showed that the equivalent capacitance depends upon all five capacitors. However, in this paper, we point out that there is a special case where the equivalent capacitance does not depend upon one of the five capacitors.

Finding The Minimum Input Impedance Of A Second-Order Twofold-Gain Sallen-Key Low-Pass Filter Without Calculus, Kenneth V. Cartwright, Edit J. Kaminsky

Electrical Engineering Faculty Publications

We derive an expression for the input complex impedance of a Sallen-Key second-order low-pass filter of twofold gain as a function of the natural frequency ωo and the quality factor Q. From this expression, it is shown that the filter behaves like a Frequency Dependent Negative Resistance (FDNR) element for low frequencies and as a single resistor at high frequencies. Furthermore, the minimum input impedance magnitude is found without using calculus. We discovered that the minimum input impedance magnitude is inversely proportional to Q and can be substantially less than its high-frequency value. Approximations to the minimum input impedance and …

Design Of A Mobile Web-Based Dashboard To Improve Work Practices Of Crna Board Runners, Mahesh Sreedharan

All Theses

Traditional artifacts such as whiteboards serve as key tools in helping healthcare professionals keep track of frequently changing information and managing their work schedule. The simplicity of these tools has made them easy to adopt into the work culture and since these artifacts are not usually electronic, they need no external technical support or maintenance. However, these artifacts present unique challenges to their users, the primary one being lack of mobility offered. The whiteboards are usually stationary and the users will have to assemble near them to update or gather information. In a hospital, this adds significant overhead to the …

Design, Analysis And Implementation Of An Experimental System To Harvest Energy From Atmospheric Temperature Variations Using Ethyl Chloride Filled Bellows, Gibran Ali

All Theses

The increase in global warming and the dwindling supplies of fossil fuels have shifted the focus from traditional to alternate sources of energy. This has resulted in a concerted effort towards finding new energy sources as well as better understanding traditional renewable energy sources such as wind and solar power. In addition to the shift in focus towards alternate energy, the last two decades have offered a dramatic rise in the use of digital technologies such as wireless sensor networks that require small but isolated power supplies. Energy harvesting, a method to gather energy from ambient sources including sunlight, vibrations, …

Long-Acting Antituberculous Therapeutic Nanoparticles Target Macrophage Endosomes, Benson J. Edagwa, Dongwei Guo, Pavan Puligujja, Han Chen, Joellyn Mcmillan, Xinming Liu, Howard Gendelman, Prabagaran Narayanasamy

Nebraska Center for Biotechnology: Faculty and Staff Publications

Eradication of Mycobacterium tuberculosis (MTB) infection requires daily administration of combinations of rifampin (RIF), isoniazid [isonicotinylhydrazine (INH)], pyrazinamide, and ethambutol, among other drug therapies. To facilitate and optimize MTB therapeutic selections, a mononuclear phagocyte (MP; monocyte, macrophage, and dendritic cell)-targeted drug delivery strategy was developed. Long-acting nanoformulations of RIF and an INH derivative, pentenyl- INH (INHP), were prepared, and their physicochemical properties were evaluated. This included the evaluation of MP particle uptake and retention, cell viability, and antimicrobial efficacy. Drug levels reached 6 μg/106 cells in human monocyte-derived macrophages (MDMs) for nanoparticle treatments compared with 0.1 μg/106 cells for native …

Direct Synthesis Of Methane From Co2-H2O Co-Electrolysis In Tubular Solid Oxide Electrolysis Cells, Long Chen, Fanglin Chen, Changrong Xia

Faculty Publications

Directly converting CO₂ to hydrocarbons offers a potential route for carbon-neutral energy technologies. Here we report a novel design, integrating the high-temperature CO₂–H₂O co-electrolysis and low-temperature Fischer–Tropsch synthesis in a single tubular unit, for the direct synthesis of methane from CO₂ with a substantial yield of 11.84%.

Investigation Of Fatigue Life And Fracture Mechanics Of Unconstrained Ni-Mn-Ga Single Crystals, Theodore Bryson Lawrence

Boise State University Theses and Dissertations

Ni-Mn-Ga is a magnetic shape memory alloy (MSMA) that exhibits large recoverable strains. The magnetic field induced strain (MFIS) occurs through twin boundary motion resulting in reorientation of the crystal structure, which is coupled to the magnetic moment of the material. The shape memory capabilities of the material make it promising for applications including microactuators, sensors, microfluid pumps, refrigeration, energy harvesting, and data storage.

In order for Ni-Mn-Ga to become a viable option for use in commercial applications the performance and reliability must be on par with industry standards. Ni‑Mn-Ga has been shown to achieve high cycles at low strains, …

Sensitivity Of Columbia Basin Runoff To Long-Term Changes In Multi-Model Cmip5 Precipitation Simulations, Mehmet Demirel, Hamid Moradkhani

Civil and Environmental Engineering Faculty Publications and Presentations

In this study, we used precipitation elasticity index of streamflow, to reflect on the sensitivity of streamflow to changes in future precipitation. We estimated precipitation elasticity of streamflow from: (1) simulated streamflow by the VIC model using observed precipitation for the current climate (1963–2003); (2) simulated streamflow by the VIC model using simulated precipitation from 10 GCM - CMIP5 dataset for the future climate (2010–2099) including two different pathways (RCP4.5 and RCP8.5) and two different downscaled products (BCSD and MACA). The hydrological model was calibrated at 1/16 latitude-longitude resolution and the simulated streamflow was routed to the subbasin outlets of …

Gis Framework For Spatiotemporal Mapping Of Urban Flooding And Analyze Watershed Hydrological Response To Land Cover Change, Sayed Joinal Hossain Abedin

UNLV Theses, Dissertations, Professional Papers, and Capstones

Urban flooding is a manmade disaster, and a recurrent problem in cities around the globe. Increased surface imperviousness due to urbanization along with inadequate drainage infrastructure system are the chief culprits for urban flooding. Flooding in an urban area brings about severe economic, structural, and environmental damages, and can be associated with casualties too. In order to evade flooding, an efficient flood model is imperative to study current flooding, and analyze flooding behavior to urban surface characteristics.

This research aims to develop a framework using Geographic Information System (GIS) to perform modeling and mapping of flood spatiotemporal variation in urban …

Investigation Of Chloride Induced Corrosion Of Bridge Pier And Life-Cycle Repair Cost Analysis Using Fiber Reinforced Polymer Composites, Dinesh Dhakal

UNLV Theses, Dissertations, Professional Papers, and Capstones

Bridges are the long term investment of the highway agencies. To maintain the required service level throughout the life of a bridge, a series of maintenance, repair, and rehabilitation (MR&R) works can be performed. To investigate the corrosion deterioration and maintenance and repair practices in the bridge pier columns constructed in chloride-laden environment, a questionnaire survey was conducted within the 50 state Departments of Transportation (DOTs). Based on the survey data, two corrosion deterioration phases were identified. They were corrosion crack initiation phase and corrosion propagation phase. The data showed that the mean corrosion crack initiation phase for bridge pier …

Novel Deployment Of Elpasolites As A Dual Neutron / Gamma-Ray Directional Detector, Amber Lynn Guckes

UNLV Theses, Dissertations, Professional Papers, and Capstones

At a time when upholding national security has never been more important, there exists a need for the advancement of radiation detection technologies. Neutron and photon detectors are essential to fulfilling mission areas including detection and localization of missing, stolen or smuggled radiological or nuclear materials, quantification of the effects of a radiological or nuclear event, and supporting nonproliferation efforts. The aim of this study was to evaluate a new radiation detector based on the scintillation elpasolite compound Cs2LiYCl6:Ce (CLYC) for simultaneous measurements of neutron and photon flux and the localization of radiation sources. Previous studies performed on the CLYC …

Remote Sensing Based On Hyperspectral Data Analysis, Ershad Sharifahmadian

UNLV Theses, Dissertations, Professional Papers, and Capstones

In remote sensing, accurate identification of far objects, especially concealed objects is difficult. In this study, to improve object detection from a distance, the hyperspecral imaging and wideband technology are employed with the emphasis on wideband radar. As the wideband data includes a broad range of frequencies, it can reveal information about both the surface of the object and its content. Two main contributions are made in this study:

1) Developing concept of return loss for target detection: Unlike typical radar detection methods which uses radar cross section to detect an object, it is possible to enhance the process of …

Spectroscopic Investigation Of The Chemical And Electronic Properties Of Chalcogenide Materials For Thin-Film Optoelectronic Devices, Kimberly Horsley

UNLV Theses, Dissertations, Professional Papers, and Capstones

Chalcogen-based materials are at the forefront of technologies for sustainable energy production. This progress has come only from decades of research, and further investigation is needed to continue improvement of these materials.

For this dissertation, a number of chalcogenide systems were studied, which have applications in optoelectronic devices, such as LEDs and Photovoltaics. The systems studied include Cu(In,Ga)Se2 (CIGSe) and CuInSe2 (CISe) thin-film absorbers, CdTe-based photovoltaic structures, and CdTe-ZnO nanocomposite materials. For each project, a sample set was prepared through collaboration with outside institutions, and a suite of spectroscopy techniques was employed to answer specific questions about the system. These …

Simulation, And Overload And Stability Analysis Of Continuous Time Sigma Delta Modulator, Kyung Kang

UNLV Theses, Dissertations, Professional Papers, and Capstones

The ever increasing demand for faster and more powerful digital applications requires high speed, high resolution ADCs. Currently, sigma delta modulators ADCs are extensively used in broadband telecommunication systems because they are an effective solution for high data-rate wireless communication systems that require low power consumption, high speed, high resolution, and large signal bandwidths.

Because mixed-signal integrated circuits such as Continuous Time sigma delta modulators contain both analog and digital circuits, mixed signal circuits are not as simple to model and simulate as all discrete or all analog systems. In this dissertation, the delta transform is used to simulate CT …

Printing Functional Electronic Circuits And Components, Ahmed Tausif Aijazi

Dissertations

The purpose of this study was to investigate the challenges in printing reliable multilayer flexible circuits, devices and components. Gravure was used as the primary printing process for this work, but due to some limitations of gravure, other printing methods were also investigated. At first a systematic study was done to determine the optimum parameters for the gravure printing of sub 50 micron lines. Commercially available silver nanoparticle inks were printed on a lab scale gravure printer, Accupress®. The highest resolution line that was electrically conductive was 36μm wide. The 9μm, 18μm and 27μm lines were printed but were not …

Fabrication, Testing And Analysis Of A Fatigue Sensor For Structural Health Monitoring, Subash Gokanakonda

Dissertations

A novel fatigue monitoring sensor (FMS) is designed, fabricated and tested for detecting and monitoring the fatigue damage and estimating the remaining life of structures and components subjected to cyclic loads. The concept is based on the characteristics of stress / strain life cycle relationship of engineering materials. Sensor consists of alternate slots and strips having different strain magnification factor with respect to the nominal strain. The sensor is designed in such a way that the strips will experience the strain which closely resemble the actual strain distribution in the notch or critical area of the component. The sensor can …

Lntegration Of Conventional Lithography And Printing Processes As A Key Enabling Technology For Printed And Flexible Sensing Systems, Binu Baby Narakathu

Dissertations

Sensors, which are used ubiquitously in a wide variety of applications, are revolutionizing the already ever-changing world we live in by providing real-time information about our surroundings. This dissertation focuses on the integration of conventional photolithography and printing processes as a key enabling technology for printed and flexible sensing systems.

Initially, an efficient opto-electrochemical sensing system, for the dual detection of heavy metal compounds was successfully developed. A novel microfluidic flow cell, with a reservoir volume of 25 μl, was designed and fabricated using acrylic. An electrochemical sensor with gold (Au) interdigitated electrodes (IDE) on a glass substrate was photolithographically …

Slow Strain Rate Testing And Stress Corrosion Cracking Of Ultra-Fine Grained And Conventional Al–Mg Alloy, Mala M. Sharma, Josh D. Tomedi, Timothy J. Weigley

Faculty Journal Articles

Stress corrosion cracking susceptibility was investigated for an ultra-fine grained (UFG) Al–7.5Mg alloy and a conventional 5083 H111 alloy in natural seawater using slow strain rate testing (SSRT) at very slow strain rates between 1E⁻⁵ s⁻¹, 1E⁻⁶ s⁻¹ and 1E⁻⁷ s⁻¹. The UFG Al–7.5Mg alloy was produced by cryomilling, while the 5083 H111 alloy is considered as a wrought manufactured product. The response of tensile properties to strain rate was analyzed and compared. Negative strain rate sensitivity was observed for both materials in terms of the elongation to failure. However, the UFG …

Shape/Image Registration For Medical Imaging : Novel Algorithms And Applications., Ahmed Magdy Shalaby 1982-

Electronic Theses and Dissertations

This dissertation looks at two different categories of the registration approaches: Shape registration, and Image registration. It also considers the applications of these approaches into the medical imaging field. Shape registration is an important problem in computer vision, computer graphics and medical imaging. It has been handled in different manners in many applications like shapebased segmentation, shape recognition, and tracking. Image registration is the process of overlaying two or more images of the same scene taken at different times, from different viewpoints, and/or by different sensors. Many image processing applications like remote sensing, fusion of medical images, and computer-aided surgery …

Transient Heat Transfer Between A Magnetocaloric Packed Particle Bed And Stagnant Interstitial Fluid., Michael G. Schroeder 1988-

Electronic Theses and Dissertations

In the field of magnetocaloric heat pumps, many system models have been made. What most of these models lack is heat transfer occurring while there is no fluid motion. It is the objective of this paper to analytically determine and experimentally verify heat transfer with no bulk fluid motion. The addition of a pure dwell period to the typical magnetocaloric cycle was shown to have a positive performance impact in specific conditions. These conditions correspond to regenerators that are heat transfer rate limited in operation. The heat transfer mechanism for this particular case was shown to be pure conduction via …

Ensemble Learning Method For Hidden Markov Models., Anis Hamdi

Electronic Theses and Dissertations

For complex classification systems, data are gathered from various sources and potentially have different representations. Thus, data may have large intra-class variations. In fact, modeling each data class with a single model might lead to poor generalization. The classification error can be more severe for temporal data where each sample is represented by a sequence of observations. Thus, there is a need for building a classification system that takes into account the variations within each class in the data. This dissertation introduces an ensemble learning method for temporal data that uses a mixture of Hidden Markov Model (HMM) classifiers. We …

Multilayer Electret Activated By Direct Contact Silicon Electrode., Mark M. Crain

Electronic Theses and Dissertations

Electrets used in microelectromechanical systems (MEMS) devices are often formed by corona charging, where ionized gases are generated in an electric field to introduce a charge to the electret surface. The purpose of this study was to investigate a new technique for creating an electret from a plasma enhanced chemical vapor deposition (PECVD) multilayer film of SiO2/Si3N4/SiO2 using a direct contact electrode of silicon. The electret formation takes advantage of deep traps in silicon nitride, which are known to develop from hydrogen interactions with silicon dangling bonds and, in some stoichiometries, nitrogen dangling bonds. The electret activation process has been …

A Non-Invasive Image Based System For Early Diagnosis Of Prostate Cancer., Ahmad Abdusalam Firjani Firjani Naef

Electronic Theses and Dissertations

Prostate cancer is the second most fatal cancer experienced by American males. The average American male has a 16.15% chance of developing prostate cancer, which is 8.38% higher than lung cancer, the second most likely cancer. The current in-vitro techniques that are based on analyzing a patients blood and urine have several limitations concerning their accuracy. In addition, the prostate Specific Antigen (PSA) blood-based test, has a high chance of false positive diagnosis, ranging from 28%-58%. Yet, biopsy remains the gold standard for the assessment of prostate cancer, but only as the last resort because of its invasive nature, high …

Avatar Captcha : Telling Computers And Humans Apart Via Face Classification And Mouse Dynamics., Darryl Felix D’Souza

Electronic Theses and Dissertations

Bots are malicious, automated computer programs that execute malicious scripts and predefined functions on an affected computer. They pose cybersecurity threats and are one of the most sophisticated and common types of cybercrime tools today. They spread viruses, generate spam, steal personal sensitive information, rig online polls and commit other types of online crime and fraud. They sneak into unprotected systems through the Internet by seeking vulnerable entry points. They access the system’s resources like a human user does. Now the question arises how do we counter this? How do we prevent bots and on the other hand allow human …