Engineering Commons^™

Simulation Of An Air Cooled Single-Effect Solar Absorption Cooling System With Evacuated Tube Collectors, Mohsen Jahandardoost

UNLV Theses, Dissertations, Professional Papers, and Capstones

Consistently increasing CO2 emission and ozone depletion from synthetic refrigerants are serious environmental issues challenging the scientific community. Absorption cooling systems give scope of utilizing low grade energy source for generating cooling effect. Solar energy is one of these low grade energy sources and with considering the fact that cooling demand increases with the intensity of solar radiation, solar refrigeration has been considered as a logical solution.

This thesis consists of two different simulation stages, in the first stage, a single effect lithium bromide absorption cooling system with constant cooling capacity is modeled and the effect of ambient and generator …

Sound Attenuation Of Fiberglass Lined Ventilation Ducts, Jacob Albright

UNLV Theses, Dissertations, Professional Papers, and Capstones

Sound attenuation is a crucial part of designing any HVAC system. Most ventilation systems are designed to be in areas occupied by one or more persons. If these systems do not adequately attenuate the sound of the supply fan, compressor, or any other source of sound, the affected area could be subject to an array of problems ranging from an annoying hum to a deafening howl. The goals of this project are to quantify the sound attenuation properties of fiberglass duct liner and to perform a regression analysis to develop equations to predict insertion loss values for both rectangular and …

Designing, Building And Testing A Solar Thermoelectric Generation, Steg, For Energy Delivery To Remote Residential Areas In Developing Regions, Yacouba Moumouni

UNLV Theses, Dissertations, Professional Papers, and Capstones

New alternatives and inventive renewable energy techniques which encompass both generation and power management solutions are fundamental for meeting remote residential energy supply and demand today, especially if the grid is quasi-inexistent. Solar thermoelectric generators can be a cost-effective alternative to photovoltaics for a remote residential household power supply. A complete solar thermoelectric energy harvesting system is presented for energy delivery to remote residential areas in developing regions. To this end, the entire system was built, modeled, and then validated with LTspice simulator software via thermal-to-electrical analogy schemes. Valuable data in conjunction with two novel LTspice circuits were obtained, showing …

The Comparison Of Two Supine Manikins And The Use Of A Shock And Vibration Isolation System For Litter Patients In Air Medical Transport, Karina Karlui Saenz Acosta

UNLV Theses, Dissertations, Professional Papers, and Capstones

Studies show that repeated shock and vibration during aero medical and ground transport are causing patient pain and may be adversely affecting patients’ medical outcome. Patients with spine and head injuries and other severe neurological injuries are the most vulnerable to repeated shock and vibration exposure caused by the vehicle. It is crucial to minimize the effects of these forces on patients during air and ground medical transport. The development of new medical evacuation platforms creates a need to better understand the effects of human exposure to shock and vibration. The use of human subjects to measure whole body vibration …

An Approach To Model Plastic Deformation Of Metallic Plates In Hypervelocity Impact Experiments, Shawoon Kumar Roy

UNLV Theses, Dissertations, Professional Papers, and Capstones

Space structures are subjected to micro-meteorite impact at extremely high velocities of several kilometers per second. Similarly, design of military equipment requires understanding of material behavior under extremely high pressure and temperature. Study of material behavior under hypervelocity impact (HVI) poses many challenges since few researchers so far have approached this problem. Material models, equations of the state, and fracture mechanics are not well understood under these conditions.

The objective of this research is to present an approach for studying plastic deformation of metallic plates under HVI conditions. A two-stage light gas gun can be used to simulate these conditions …

Feasibility Study Of Custom Manufacturing Of Ionic Polymer-Metal Composite Sensors, Shelby E. Nelson

UNLV Theses, Dissertations, Professional Papers, and Capstones

The ability to create an ion exchange membrane with any shape or thickness through custom manufacturing techniques is highly desirable in ionic polymer-metal composite (IPMC) research. This is caused by the poor selection and limited availability of certain thicknesses of commercial ion exchange membranes. The objective of this study is to determine the feasibility of manufacturing custom ion exchange membranes for IPMC sensors. The manufacturing methods used in this study are extrusion, injection molding, and hot pressing. A commercial membrane from Golden Energy Fuel Cells (GEFC) is used as a comparison. After the membranes are fabricated, certain properties of the …

Cfd Simulation Of Heat Enhancement In Internally Helical Grooved Tubes, Sogol Pirbastami

UNLV Theses, Dissertations, Professional Papers, and Capstones

Heat exchanger devices are widely used in industries, air conditioning systems, refrigeration, etc. These devices have a major role in energy conservation; therefore, increasing the performance of heat exchangers helps save energy, costs and materials. The technique to increase the heat transfer performance is called heat augmentation, which can be applied to pipe surfaces and other surfaces which are used in heat exchangers to improve thermal performance. These techniques are categorized into 3 groups: passive, active and compound technique. In this study a helically machined rectangular groove on the inside of a 2.0 m tube with a diameter of 7.1mm …

The Design, Build, And Validation Of A Hybrid Tower Used To Conduct Helmet Impact Tests, Darren Benn

UNLV Theses, Dissertations, Professional Papers, and Capstones

The National Operating Committee on Standards for Athletic Equipment (NOCSAE) was established to enlist research directed towards the reduction of head injuries in organized sports. The function of the test methods developed by NOCSAE is to provide the blueprint for reliable and repeatable procedures to measure the evaluation of various types of protective sports headgear and projectiles. In addition, the methods also govern hardware such as testing apparatus and data acquisition instrumentation. In helmet testing, the method dictates whether the impact is induced by a projectile system or by a drop tower system with an anvil at the base. Altogether, …