Open Access. Powered by Scholars. Published by Universities.®
- Discipline
-
- Physical Sciences and Mathematics (207)
- Civil and Environmental Engineering (182)
- Electrical and Computer Engineering (169)
- Mechanical Engineering (161)
- Civil Engineering (128)
-
- Computer Engineering (83)
- Materials Science and Engineering (80)
- Environmental Sciences (79)
- Computer Sciences (50)
- Engineering Science and Materials (50)
- Environmental Engineering (50)
- Social and Behavioral Sciences (45)
- Nuclear Engineering (42)
- Oil, Gas, and Energy (41)
- Physics (36)
- Biomedical Engineering and Bioengineering (30)
- Public Affairs, Public Policy and Public Administration (29)
- Aerospace Engineering (28)
- Transportation (24)
- Chemistry (23)
- Earth Sciences (23)
- Biomedical Devices and Instrumentation (21)
- Medicine and Health Sciences (21)
- Sustainability (21)
- Biomechanical Engineering (20)
- Biomedical (20)
- Artificial Intelligence and Robotics (19)
- Nanoscience and Nanotechnology (19)
- Chemical Engineering (17)
- Keyword
-
- Harry Reid Center (15)
- Applied sciences (9)
- Energy consumption (8)
- Nevada (8)
- Traffic safety (8)
-
- CFD (7)
- Machine Learning (7)
- Machine learning (7)
- Simulation (7)
- Concrete (6)
- Remote sensing (6)
- Robotics (6)
- Strains and stresses (6)
- Stress corrosion (6)
- Actuators (5)
- Computational fluid dynamics (5)
- Deep learning (5)
- Impact (5)
- Optimization (5)
- Photovoltaic (5)
- Solar (5)
- Solar Energy (5)
- Sustainability (5)
- Traffic accidents (5)
- Wastewater (5)
- Climatic changes (4)
- Control (4)
- Corrosion (4)
- Energy (4)
- Eutectic alloys (4)
Articles 1 - 30 of 594
Full-Text Articles in Engineering
Survey Of How Irregularities In The Electrical System Of The Human Heart Link To Different Heart Arrhythmias, Jazmine Boloor
Survey Of How Irregularities In The Electrical System Of The Human Heart Link To Different Heart Arrhythmias, Jazmine Boloor
UNLV Theses, Dissertations, Professional Papers, and Capstones
This thesis explores the circuital pathway that a signal takes within the heart throughout a full heartbeat and provides a timing analysis. It then surveys the different pathways that could arise in the electrical system of the heart, and the associated heart diseases linked to the location of each pathway. Common heart arrhythmias such as atrioventricular nodal reentrant tachycardia, atrioventricular reentrant tachycardia, atrial flutter, and atrial fibrillation are surveyed, and their pathways are analyzed. Electrocardiograms are presented to aid in understanding of the timing analysis associated with irregularity in heart function. Finally, this thesis explores an avenue of the heartbeat …
An Avalanche Transistor-Based Pulse Generator Design For Infrared Laser Applications, Abraham Lopez
An Avalanche Transistor-Based Pulse Generator Design For Infrared Laser Applications, Abraham Lopez
UNLV Theses, Dissertations, Professional Papers, and Capstones
This thesis details the design and results of a circuit intended for infrared laser applications, specifically for transcranial infrared light simulation (TILS) experiments and for use as a range finder. The circuit itself is comprised of a transistor, high voltage power supply, laser diode, capacitor, resistor, diode, and low voltage pulse. The design of a range finder is also developed. The range finder design is the same as the circuit developed for TILs with the addition of a few more components for receiving the returned light pulse such as a photodiode, op-amp, and comparator. The techniques used for a successful …
Development Of Pre-Magnetized Magnetorheological Elastomer For Bidirectionally Variable Stiffness Applications, Choonghan Lee
Development Of Pre-Magnetized Magnetorheological Elastomer For Bidirectionally Variable Stiffness Applications, Choonghan Lee
UNLV Theses, Dissertations, Professional Papers, and Capstones
Magnetorheological elastomers (MREs) utilize magnetic forces between ferromagnetic particles to cause variable stiffness properties and damping with external magnetic fields. In the MREs, the particles are embedded in a cured elastomer matrix, and an external magnetic field makes the stiffness change due to induced magnetic forces among particles. A disadvantage of the conventional MREs is that they cannot be softened (reduced stiffness) under an external magnetic field. Considering that there are many engineering applications where fast changes of stiffness in both directions (stiffening and softening) are required, embedding magnetically biased particles in the MRE can provide potential solutions. In this …
Development And Characterization Of Lead & Lead-Free Perovskite Solar Cell Materials, Rubaiya Murshed
Development And Characterization Of Lead & Lead-Free Perovskite Solar Cell Materials, Rubaiya Murshed
UNLV Theses, Dissertations, Professional Papers, and Capstones
In recent years, perovskite photovoltaic technology has offered enormous viability and dimensionality in solar cell research. As a light-harvesting active layer, Perovskite generated remarkable development in device efficiency of 25.7% for the single-junction solar cell, and over 33% for the perovskite/silicon tandem solar cell. Also, perovskite-perovskite tandem solar cell (also called all-perovskite tandem solar cell) shows great potential in device performance and achieved a power conversion efficiency (PCE) of 26.4%. Transitioning photovoltaic technology from the laboratory to commercial products, high PCE, low cost, long lifetime, and low toxicity are some of the critical factors to consider during material selection. Pb-halide …
Towards Cfd Investigations Into Particulate Air Pollution Of A Desert Urban Environment, Prosun Roy
Towards Cfd Investigations Into Particulate Air Pollution Of A Desert Urban Environment, Prosun Roy
UNLV Theses, Dissertations, Professional Papers, and Capstones
This dissertation has explored computational fluid dynamics (CFD) techniques for studying particulate air quality in the Las Vegas urban area. The dissertation is based on three research tasks: • High time-resolution fenceline air quality sensing and dispersion modeling for environmental justice-centered source attribution. (Chapter 2) • Pollen dispersion and deposition in real-world urban settings: A computational fluid dynamic study. (Chapter 3) • Effects of urban canopy parameterizations on modeling pollen dispersion and exposure. (Chapter 4) In Chapter 2, we investigate the facilitation of low-cost air quality sensors (LCAQS) and CFD technique on exposure assessment of environmental justice (EJ) communities and …
Facial Expression Recognition Using Convolutional Neural Networks (Cnns) And Generative Adversarial Networks (Gans) For Data Augmentation And Image Generation, Shekhar Singh
UNLV Theses, Dissertations, Professional Papers, and Capstones
Facial expressions play a crucial role in human communication, serving as a powerful means to convey emotions. However, classifying facial expressions using artificial intelligence (AI) can be challenging, especially with small datasets and images. Facial Expression Recognition (FER) is an active area of research, with Convolutional Neural Networks (CNNs) being widely employed for classification. In this research, we propose a CNN-based approach for FER that utilizes both original and augmented datasets to enhance classification accuracy. Experimental results on the FER2013 dataset show test accuracies of 63.39% and 64.59% for the original and augmented datasets, respectively, in a seven-class classification task. …
Non-Destructive Means Of Predicting Masonry Prism Strength Using Ultrasonic Pulse Velocity (Upv), Connor J. Barlow
Non-Destructive Means Of Predicting Masonry Prism Strength Using Ultrasonic Pulse Velocity (Upv), Connor J. Barlow
UNLV Theses, Dissertations, Professional Papers, and Capstones
Current ASTM standards call for grouted masonry prisms to be tested for compressive strength at 28-days to ensure compliance with the structural design. In the event of failing tests, the subject samples may require redesign or reconstruction which can pose problems due to ongoing development around and including the prisms between the time of placement and obtaining test results. The purpose of this research is to determine if the use of ultrasonic pulse velocity (UPV) testing can be utilized to determine a correlation between prism composite strength of the masonry prism with ultrasound readings as to provide preliminary means of …
Trajectory Analysis For Driving Safety Quantification, Michael I. Chang
Trajectory Analysis For Driving Safety Quantification, Michael I. Chang
UNLV Theses, Dissertations, Professional Papers, and Capstones
In order to evaluate the efficacy of the skid recovery exercise in the Driver’s Edge teenage driving program, a process is established to determine the trajectories of vehicles from recorded videos, compare them in terms of similarity through dynamic time warping (DTW), and then analyze the similarity measurements to assess whether the program has a significant effect on driving ability by repeated measures analysis of variance (rANOVA). The video is analyzed by Harris corner detection and Lucas-Kanade optical flow method to ascertain the vehicle trajectories. A homography is then estimated to translate coordinates from video into real-world. The instructor and …
Time-Dependent Wetting Behavior Of Hydrogels, Amir Kashani
Time-Dependent Wetting Behavior Of Hydrogels, Amir Kashani
UNLV Theses, Dissertations, Professional Papers, and Capstones
Hydrogels are 3-D polymers with hygroscopic properties that enable them to absorb and retain large amounts of water. In many applications such as biomedical applications, including drug delivery, wound healing, tissue engineering, biosensors, and contact lenses, agriculture, food and beverage, cosmetics, and environmental, hydrogels also need to maintain a high degree of wetting in order to ensure effective functionality and interaction with surrounding fluids or tissues in desired applications. The combination of wetting and absorptive behavior of hydrogels that are often encountered in biomedical, biological, industrial and the mentioned applications presents a challenging physical problem that is not completely understood. …
Enhanced Iot-Based Electrocardiogram Monitoring System With Deep Learning, Jian Ni
Enhanced Iot-Based Electrocardiogram Monitoring System With Deep Learning, Jian Ni
UNLV Theses, Dissertations, Professional Papers, and Capstones
Due to the rapid development of computing and sensing technologies, Internet of Things (IoT)-based cardiac monitoring plays a crucial role in providing patients with cost-efficient solutions for long-term, continuous, and pervasive electrocardiogram (ECG) monitoring outside a hospital setting. In a typical IoT-based ECG monitoring system, ECG signals are picked up by sensors located on the edge, and then uploaded to the remote cloud servers. ECG interpretation is performed for the collected ECGs in the cloud servers and the analysis results can be made instantly available to the patients as well as their healthcare providers.In this dissertation, we first examine the …
A One-Dimensional Analysis Of A Microbial Fuel Cell For Efficient Acetate Removal And Power Density Output, David Rouhani
A One-Dimensional Analysis Of A Microbial Fuel Cell For Efficient Acetate Removal And Power Density Output, David Rouhani
UNLV Theses, Dissertations, Professional Papers, and Capstones
Microbial fuel cells (MFCs) are electrochemical devices that utilize microorganisms to convert organic matter into electrical energy. MFCs have been discussed to have potential application for sustainable wastewater treatment due to their ability to generate electricity while simultaneously treating contaminated water. To optimize MFC performance, numerical models can be used to understand the complex electrochemical and biological processes occurring in the system. In this study, a numerical model was developed to simulate the performance of MFCs under varying operating conditions and to investigate the performance of a MFC for treating wastewater fuel. More specifically, the MFC was modeled to oxidize …
Development Of An Automated Gpib System For Characterization Of Sige Avalanche Photodiodes, David A. Santiago
Development Of An Automated Gpib System For Characterization Of Sige Avalanche Photodiodes, David A. Santiago
UNLV Theses, Dissertations, Professional Papers, and Capstones
Photon counting is a technique in many modern technologies such as medical imaging and LiDAR systems. Photon counting is needed in many aspects of the development process for these technologies from photodetector characterization to operation of the finished product. This thesis will serve to solve the challenge of quantifying photodetector performance using automating test equipment with known software packages such as MATLAB to be able tocharacterize photodetectors in an efficient manner. A custom MATLAB program has been developed to interface with various instrumentation using a General-Purpose Interface Bus (GPIB) and a Prologix GPIB-USB controller that will be able to send …
Monitoring And Classification Of Tissue Perfusion Through The Combined Use Of Thermal, Rgb, And Laser Speckle Contrast Imaging, Ivan Soto
UNLV Theses, Dissertations, Professional Papers, and Capstones
In cooperation with the UNLV School of Medicine, this thesis is part of a bigger project aimed at developing a post-op surgery device for the constant unattended monitoring of a patient’s tissue. This device is intended to monitor areas of surgical sites and detect any complications without the need for continuous supervision by medical professionals. One such complication includes inadequate tissue perfusion, or a lack of blood flow reaching a patient’s tissue. The role of this thesis is to fit a convolutional neural network model to the available data gathered from voluntary participants and attempt to classify the data as …
Metastability And Degradation In Cu(In,Ga)Se2 Thin-Film Solar Cells, Mohsen Jahandardoost
Metastability And Degradation In Cu(In,Ga)Se2 Thin-Film Solar Cells, Mohsen Jahandardoost
UNLV Theses, Dissertations, Professional Papers, and Capstones
Cu(In,Ga)(S,Se)2 or CIGS is a thin-film semiconductor that has shown a device efficiency of 23.35% and 24.2% for single-junction and perovskite/CIGS tandem solar cells, respectively. CIGS offers promising properties such as tunable bandgap and ease of processing making them great candidates for thin-film tandem devices. However, knowledge of the effect of material defects, buffer materials, and post-deposition treatment (PDT) on degradation and metastability behavior in these devices is not well understood.In this dissertation, metastability and long-term degradation of CIGS thin-film solar cells have been investigated under combinatorial stress factors of heat, light, and voltage bias to systematically understand the effect …
Information-Theoretic Model Diagnostics (Infomod), Armin Esmaeilzadeh
Information-Theoretic Model Diagnostics (Infomod), Armin Esmaeilzadeh
UNLV Theses, Dissertations, Professional Papers, and Capstones
Model validation is a critical step in the development, deployment, and governance of machine learning models. During the validation process, the predictive power of a model is measured on unseen datasets with a variety of metrics such as Accuracy and F1-Scores for classification tasks. Although the most used metrics are easy to implement and understand, they are aggregate measures over all the segments of heterogeneous datasets, and therefore, they do not identify the performance variation of a model among different data segments. The lack of insight into how the model performs over segments of unseen datasets has raised significant challenges …
Investigating Haloacetonitrile (Han) Formation Potential From Nitrogenous Antibiotics And Agrochemicals, Kazi Shafayet Haider
Investigating Haloacetonitrile (Han) Formation Potential From Nitrogenous Antibiotics And Agrochemicals, Kazi Shafayet Haider
UNLV Theses, Dissertations, Professional Papers, and Capstones
Disinfection can promote safe drinking water. Chlorine and chloramines are the two most used disinfectants. While these disinfectants are effective in inactivating disease-causing pathogens, they also produce hazardous byproducts when they react with organic compounds (precursors). Nitrogenous disinfection byproducts (N-DBPs) are more toxic than their counterparts. The increased use of nitrogen-based agrochemicals and antibitics has led to their detection in different water sources. The presence of secondary amine and aniline in these compounds can act as a source of reactive nitrogen to form N-DBPs. In addition, the increased concentration of bromide in water systems due to anthropogenic activities can enhance …
Simulating Condensation In The Theory Of Classical Nucleation, David Vallet
Simulating Condensation In The Theory Of Classical Nucleation, David Vallet
UNLV Theses, Dissertations, Professional Papers, and Capstones
The scope of this thesis is to numerically investigate condensation that occurs in transonic and supersonic flows. Condensation shocks are a phenomenon that occurs within converging-diverging nozzles. There are many applications forconverging-diverging nozzles, such as thermovapour compressors (TVC), which are largely used for desalination. As water resources become more precious within the western United States there is a need to develop cost effective solutions for cleaning water. Steam generator power stations are another application where enhanced simulations and accuracy of design could improve efficiency and save on carbon emissions. Traditionally, numerical designs of transonic flows have been conducted with either …
Nexuscapes: A Landscape Approach For A Transdisciplinary Water-Energy-Food Nexus Decision-Making Process, Fortino Acosta
Nexuscapes: A Landscape Approach For A Transdisciplinary Water-Energy-Food Nexus Decision-Making Process, Fortino Acosta
UNLV Theses, Dissertations, Professional Papers, and Capstones
This study develops a reliable transdisciplinary framework for complex ecological and social systems by characterizing, mapping, typifying, assessing, and testing enhanced water-energy-food nexus scenarios under critical time constraints, specialized skills, or sensitive data accessibility. Detached management of limited essential resources like fresh water, reliable energy from renewable sources, and nutritious food can jeopardize regional economies and governance. Using a novel landscape approach, this study recommends a decision-making the framework focused on the circular economy that induces collaboration among diverse sectors and brings strategic coordination, specificity, and magnitude to the proposed solutions. The study elaborates on a decision-making tool that integrates …
Application Of Experimentally Calibrated Numerical Models For Prediction Of Composite Masonry Prism Strength, James Bristow
Application Of Experimentally Calibrated Numerical Models For Prediction Of Composite Masonry Prism Strength, James Bristow
UNLV Theses, Dissertations, Professional Papers, and Capstones
The composite masonry prism test is a common laboratory test to determine the compressive strength of a set of masonry prisms (f’mt) to verify that the composite masonry prism assembly, and more importantly, the constituent materials, are providing adequate strength. While constructing masonry structures, the subcontractors, designers, and inspectors rarely provide continuous supervision or inspection of the construction process. Accordingly, verification of grout mix design, mixed proportions, proper installation of blocks, placement of mortar, dimensions of joints, etc. are more traditionally performed on a periodic basis instead. However, through the use and review of the composite masonry prism test results, …
Effects Of Particle Size And Replacement Proportion Of Post-Consumer Glass In Concrete, Negasi Gebremichael
Effects Of Particle Size And Replacement Proportion Of Post-Consumer Glass In Concrete, Negasi Gebremichael
UNLV Theses, Dissertations, Professional Papers, and Capstones
Concrete, next to water, is the most used material (Gagg, 2014), which consumes natural or manufactured aggregates and resource-intensive cement. Concrete is also a more wasteful construction material than timber and steel. Depleting the natural resource due to aggregate extraction and the environmental unfriendliness of cement production have left the construction industry with no choice. Reducing waste, reusing, or recycling can help conserve natural resources. In this regard, the construction industry constantly seeks full or partial replacement of concrete aggregates and cement with recycled material. Glass is a candidate for replacing the three major components: cement, fine aggregate, and coarse …
Towards The Electronic Response Of Carbon-Based Van Der Waals Heterostructures In A Diamond Anvil Cell, George Thomas Foskaris
Towards The Electronic Response Of Carbon-Based Van Der Waals Heterostructures In A Diamond Anvil Cell, George Thomas Foskaris
UNLV Theses, Dissertations, Professional Papers, and Capstones
The nanoscale regime of materials has been at the forefront of research and interest in condensed matter physics for many years. In a merger of the fields of two-dimensional (2D) materials and high pressure physics, we present an investigation of the electronic response of carbon-based, van der Waals (vdW) heterostructures in a diamond anvil cell (DAC). Combining these fields presents us with the ability to study the characteristics of such systems both optically, and through electrical transport. Properties such as conductance, band structure, and layer number are considered. The samples in this study are assembled using exfoliation and stacking techniques …
Dynamic Surface Tension Of Surfactants Through Separation Of Diffusion And Dilation Effects, Brandon Ortiz
Dynamic Surface Tension Of Surfactants Through Separation Of Diffusion And Dilation Effects, Brandon Ortiz
UNLV Theses, Dissertations, Professional Papers, and Capstones
Surfactants are biphilic monomers that adsorb to interfaces and have the ability to reduce interfacial tension. From this reduction in interfacial tension, surfactants are able to function as emulsifiers, detergents, and wetting agents among a variety of other things. Despite their ubiquity surfactants and surfactant behaviors, in particular those in highly dynamic environments, are not yet well characterized. In these environments, surfactants undergo significant distortions to droplet, bubble, and foam geometries which induce changes to the surface tension. This establishes a need to understand how surfactants respond to distortions of geometry through diffusion and dilational effects. To address this need, …
Developing A Hands-On Class Exercise For Modular Construction, 3d Design, And 4d Schedule, Kyle A. Kithas
Developing A Hands-On Class Exercise For Modular Construction, 3d Design, And 4d Schedule, Kyle A. Kithas
UNLV Theses, Dissertations, Professional Papers, and Capstones
Modular construction shows promise as a viable alternative to stick-built construction. A major challenge with the widespread adoption of modular construction is the construction industry’s focus on minimizing risk and defaulting to the comfort and familiarity of stick-built construction. This pattern can be broken through an educational paradigm shift in the way architecture, engineering, and construction are taught in school. Integrating modular construction education into higher education is presented to increase the future adoption of modular construction and expand the comfort zones of future industry leaders. This thesis proposes that current curriculum be augmented to teach the modular approach in …
Development And Application Of A Safety Index For Transit Stops: A Case Study From Las Vegas, Nevada, Rithesh Shivuni
Development And Application Of A Safety Index For Transit Stops: A Case Study From Las Vegas, Nevada, Rithesh Shivuni
UNLV Theses, Dissertations, Professional Papers, and Capstones
This research developed a methodology to evaluate safety proximate to transit stops through a Safety Index, identified key factors associated with fatal crashes proximate to bus transit stops, and illustrated the applications of these using a case study based on the Las Vegas metropolitan area in Nevada, USA. The methodology is based on motor vehicle crashes that involve pedestrians recorded in the proximity of transit stops, and the severity of the crash outcomes. It focused on crashes which involved pedestrians that occurred within walking distances of individual transit stops. The severity of the crash outcomes was classified based on the …
A Control Integrated Circuit For A Hysteretic Flyback Power Converter, Armani Alvarez
A Control Integrated Circuit For A Hysteretic Flyback Power Converter, Armani Alvarez
UNLV Theses, Dissertations, Professional Papers, and Capstones
This Thesis reports the design, simulation, and layout of a switching power supply controller chip for a fly-back switching power supply. The controller chip was designed using ON’s Semiconductor C5 process. The resulting switching power supply using the controller chip consists of using various off-chip components such as a power MOSFET, transformer, and capacitors. The main components used in the integrated circuit include a bandgap reference voltage circuit which outputs a reference voltage of 1.25V, a ring oscillator having a nominal frequency of 5MHz, a high-gain comparator, and a buffer that can drive a 5pF capacitor. Under normal simulation conditions …
Automated Approach For The Enhancement Of Scaffolding Structure Monitoring With Strain Sensor Data, Sayan Sakhakarmi
Automated Approach For The Enhancement Of Scaffolding Structure Monitoring With Strain Sensor Data, Sayan Sakhakarmi
UNLV Theses, Dissertations, Professional Papers, and Capstones
Construction researchers have made a significant effort to improve the safety of scaffolding structures, as a large proportion of workers are involved in construction activities requiring scaffolds. However, most past studies focused on design and planning aspects of scaffolds. While limited studies investigated scaffolding safety during construction, they are limited to simple cases only with limited failure modes and simple scaffolds. In response to this limitation, this study aims to develop an automated scaffold monitoring approach capable of monitoring large scaffolds. Accordingly, this study developed an automated scaffold safety monitoring framework that leverages sensor data collected from a scaffold, scaffold …
Measuring Impacts And Vibrations On A Volumetric Modular House During Transportation, Seung Ho Song
Measuring Impacts And Vibrations On A Volumetric Modular House During Transportation, Seung Ho Song
UNLV Theses, Dissertations, Professional Papers, and Capstones
The U.S. construction industry is experiencing an increase in demand for further implementation of modular construction due to the significant productivity and project cost-reducing benefits it provides. However, there exist challenges with the modular method, and many of them are well covered by previous studies, except for the effects of transportation-induced impact/vibration on volumetric modules. A previous study examined the effects of transportation-induced impact/vibration on a timber-framed module and identified some valuable findings. But, it did not explore other types of modules, height considerations, and the differences in the magnitude of impact/vibration due to different module maneuvers on the road. …
Identification Of Factors Contributing To Traffic Crashes By Analysis Of Text Narratives, Cristian D. Arteaga-Sanchez
Identification Of Factors Contributing To Traffic Crashes By Analysis Of Text Narratives, Cristian D. Arteaga-Sanchez
UNLV Theses, Dissertations, Professional Papers, and Capstones
The fatalities, injuries, and property damage that result from traffic crashes impose a significant burden on society. Current research and practice in traffic safety rely on analysis of quantitative data from crash reports to understand crash severity contributors and develop countermeasures. Despite advances from this effort, quantitative crash data suffers from drawbacks, such as the limited ability to capture all the information relevant to the crashes and the potential errors introduced during data collection. Crash narratives can help address these limitations, as they contain detailed descriptions of the context and sequence of events of the crash. However, the unstructured nature …
Mechanoelectrical Behavior In Polyvinyl Chloride (Pvc) Based Soft Polymer Gel Smart Sensors For Soft Robotic Applications, Justin Neubauer
Mechanoelectrical Behavior In Polyvinyl Chloride (Pvc) Based Soft Polymer Gel Smart Sensors For Soft Robotic Applications, Justin Neubauer
UNLV Theses, Dissertations, Professional Papers, and Capstones
Polyvinyl chloride (PVC) gels are a class of electroactive polymer that contain a PVC-based polymeric lattice and various amounts of plasticizer. PVC and plasticizer are industrially available and are commonly used in a wide range of applications including cable insulation, flexible hosing, and healthcare equipment. There are many plasticizer types available, some being extremely biocompatible with implementations in food-safe applications and even food additives for human consumption. Plasticizer weakly bonds to the long polymerized chains of the polymer lattice decreasing the modulus of the composite material. By adding excessive amounts of plasticizer, the bonding sites of these long carbon chains …
Enhancements To Nuclear Thermal Propulsion Rockets, Kimberly Gonzalez
Enhancements To Nuclear Thermal Propulsion Rockets, Kimberly Gonzalez
UNLV Theses, Dissertations, Professional Papers, and Capstones
Nuclear thermal rocket propulsion has been proposed as a highly efficient technology for space vehicles traveling from earth orbit to the moon, Mars, and other locations in the solar system. With twice the performance of a chemical rocket, nuclear thermal propulsion (NTP) uses the thrust produced by heating hydrogen gas within a thermal nuclear reactor where the exhaust is then passed through a de Laval nozzle to produce supersonic flow. NTP engines were the subject ofthe NERVA experiments at the Nevada Test Site in the 1970’s, and they produced a specific impulse of up to 900 seconds which is almost …