Mechanical Engineering Commons^™

Blunt And Ballistic Impacts On Human Head Models: An Analytical And Numerical Study, Yongqiang Li

Mechanical Engineering Research Theses and Dissertations

Head injuries, as a leading cause of death, have become a major health care issue for civilians and soldiers. There has been an urgent need to understand mechanisms of such injuries. The objective of this dissertation research is to study some head injuries and related mechanisms using analytical and computational models.

In Chapter 2, a new analytical (non-linear) model for the impact of a solid sphere on a fluid-filled spherical shell is developed by including the stress wave propagation effect in addition to the Hertzian contact deformations and the shell membrane and bending actions. A simplified (linearized) model incorporating the …

Risk Assessment Of Dropped Cylindrical Objects In Offshore Operations, Adelina Steven

LSU New Orleans Theses and Dissertations

Dropped object are defined as any object that fall under its own weight from a previously static position or fell due to an applied force from equipment or a moving object. It is among the top ten causes of injuries and fatality in oil and gas industry. To solve this problem, several in-house tools and guidelines is developed over time to assess the risk of dropped objects on the sub-sea structures. This thesis focuses on compiling and comparing those methods in hope to improve the recommended practices available in the market. A simple modification is done on the in-house tools …

A Numerical Study In Prediction Of Pressure On High-Speed Planing Craft During Slamming Events, Shivank Srivastava

LSU New Orleans Theses and Dissertations

This thesis is an attempt to create a computer based tool that can be used academically and later industrially by naval architects in analysis and development of efficient planing hull forms. The work contained here is based on the theory created by Vorus (1996) which falls between empirical asymptotic solutions and intractable non-linear boundary value problem in the time-domain. The computer code developed predicts pressures on the bottom of high-speed planing craft during slamming events. The code is validated with available numerical data as a benchmark case. An aluminum wedge is dropped from various heights resulting in unsteady pressure distributions …

Active Vibration Control Of Helicopter Rotor Blade By Using A Linear Quadratic Regulator, Md Mosleh Uddin

LSU New Orleans Theses and Dissertations

Active vibration control is a widely implemented method for the helicopter vibration control. Due to the significant progress in microelectronics, this technique outperforms the traditional passive control technique due to weight penalty and lack of adaptability for the changing flight conditions. In this thesis, an optimal controller is designed to attenuate the rotor blade vibration. The mathematical model of the triply coupled vibration of the rotating cantilever beam is used to develop the state-space model of an isolated rotor blade. The required natural frequencies are determined by the modified Galerkin method and only the principal aerodynamic forces acting on the …

Modeling Of Swimming Cells From Nano-Scale To Micro-Scale, Yicheng Zhao

McKelvey School of Engineering Graduate Student Theses & Dissertations

Certain human genetic diseases -- primary ciliary dyskinesia, infertility, and hydrocephalus -- are characterized by changes in beat frequency and waveform of cilia and flagella. Chlamydomonas reinhardtii, which is a single-cell green alga about ten micrometers in diameter that swims with two flagella, serves as an excellent biological model because its flagella share the same structure and genetic background as mammalian cilia and flagella. This study uses the finite element method to investigate the behavior of C. reinhardtii swimming from nano-scale to micro-scale. At the device-level, micro-scale modeling indicates that well-designed acoustic microfluidic devices can be used to trap groups …

Nanostructure-Enabled And Macromolecule-Grafted Surfaces For Biomedical Applications, Madeline Small, Addison Faglie, Alexandra J. Craig, Martha Pieper, Vivian E. Fernand Narcisse, Pierre F. Neuenschwander, Shih-Feng Chou

Mechanical Engineering Faculty Publications and Presentations

Advances in nanotechnology and nanomaterials have enabled the development of functional biomaterials with surface properties that reduce the rate of the device rejection in injectable and implantable biomaterials. In addition, the surface of biomaterials can be functionalized with macromolecules for stimuli-responsive purposes to improve the efficacy and effectiveness in drug release applications. Furthermore, macromolecule-grafted surfaces exhibit a hierarchical nanostructure that mimics nanotextured surfaces for the promotion of cellular responses in tissue engineering. Owing to these unique properties, this review focuses on the grafting of macromolecules on the surfaces of various biomaterials (e.g., films, fibers, hydrogels, and etc.) to create nanostructure-enabled …

Foil-Based Additive Manufacturing System And Method, Hai-Lung Tsai, Yiyu Shen, Yingqi Li, Chen Chen

Mechanical and Aerospace Engineering Faculty Research & Creative Works

An additive manufacturing system, method of manufacturing, and fabricated part. The system uses a material joining laser system to join together foil sheets to form a metal part. The material joining laser system can be configured to join adjacent foil sheets together in a substantially uniform manner. The manufacturing system also includes a material removal system that removes material from selected locations of the foil sheets to shape the foil sheets to correspond with selective slices of the part. The material removal system can be a laser system, such as a laser system configured to remove material from a foil …

Analysis Of Differences Between 2018 Iecc R406 Code Compliance And Ansi/Resnet/Icc Standard 301, Florida Solar Energy Center, Philip W. Fairey

FSEC Energy Research Center®

EnergyGauge USA is used to study outdoor air ventilation rates in energy-efficient, one-story 2000 ft², 3 bedroom, single-family homes in sixteen representative U.S. cities. Each of the 16 home archetypes is configured to be minimally compliant with the score requirements of Table R406.4 of the 2018 IECC as determined in accordance with ANSI/RESNET/ICC 301-2014. Each home is also configured to comply using two different compliance methods: the first with only high-efficiency options and the second utilizing on-site photovoltaic power generation. Each home configuration is evaluated using the ANSI/RESNET/ICC 301 Reference Home ventilation specification and again using the 2018 …

Numerical Analysis Of An Electrical Transformer With Fins And Horizontal Pins, Sean Ferneyhough

UNLV Theses, Dissertations, Professional Papers, and Capstones

Three-dimensional numerical simulations are run on a cylindrical electrical transformer that is generating heat in order to study the resulting natural convection that is driven by density variation. The transformer generates a constant heat flux and is incased in a sleeve with radial fins. At first, the sleeve is analyzed without fins and compared to an analytical solution in order to validate the numerical simulations. Next, fins are added to the sleeve in order to maximize the heat transfer from the transformer. Heat transfer from the sleeve per number of fins is to be determined. Small pins are then added …

Detector Arrays For Nuclear Security And Safeguards Applications, Jessica Hartman

UNLV Theses, Dissertations, Professional Papers, and Capstones

Over the last two decades it has become increasingly apparent that there is a need for new technologies capable of reliable and efficient fast neutron detection. As national and international stockpiles of 3He continue to dwindle, the need to find a new gold standard of neutron detection becomes more critical. Moreover, neutrons are generated typically in the MeV energy range. The use of 3He detectors for fast neutron measurements requires the use of moderators. Detector arrays capable of fast neutron detection are one solution to this problem. To this end, the focus of this work was the study of detector …

Preliminary Investigation Of Tensile Strength And Impact Characterization Of Cementitious Composite Incorporating Carbon Nanotubes, Robabeh Jazaei

UNLV Theses, Dissertations, Professional Papers, and Capstones

Cement has been largely used in the construction industry, specifically as a matrix for concrete. Recently, a new generation of cement-based composite that greatly increases mechanical properties is replacing conventional concrete. With periodic advances in the field, researchers considered particles with high-aspect ratios such as Carbon Nanotubes (CNTs) to reinforce cement matrices. Although there is not much literature to draw upon in research, some research on improving the tensile strength of cementitious composite incorporating with CNTs does exist. However, there had been no evidence of investigation into impact strength until this study.

Most papers presented examined the effect of multi-walled …

Design Optimization And Control Of A Fully Actuated Hexrotor Uav For Use In Aerial Manipulation Applications, Jameson Yau Sung Lee

UNLV Theses, Dissertations, Professional Papers, and Capstones

This work addresses the issue of controller complexity in the application of a special class of multirotor in aerial manipulation tasks. Much of the current research concerning aerial manipulation involves the modeling and control of highly coupled multirotor and manipulator systems. This is a consequence of the platform’s under-actuation condition. To accommodate the rejection of arbitrary wrench disturbances brought about by the environment, multirotor must perform deliberate attitude tracking to affect forward and lateral maneuvers mid-flight. The manipulator end-effector tracking is highly affected by this, thus, their performance in general aerial manipulation is limited. To address these limitations, a special …

A Numerical Model Of An Axial Wind Turbine, Andrew Liam Poland

UNLV Theses, Dissertations, Professional Papers, and Capstones

Since the beginning of the industrial revolution, there has never been more of a constant in the world than that of the demand for energy. For years a stable source has been fossil fuels, but with the growing impacts of global warming, it is important to look for renewable sources. Wind energy’s use has become more and more prevalent throughout the world.

This preliminary work runs through the creation of a three-dimensional numerical model of a conventional wind turbine that was created using ANSYS-Fluent© commercial software. This work provides the base wind turbine and a blade element and momentum theory …

The Design, Modeling, And Optimization Of A Biomimetic Soft Robot For Fluid Pumping And Thrust Generation Using Electroactive Polymer Actuators, Zakai Jedidiah Olsen

UNLV Theses, Dissertations, Professional Papers, and Capstones

Nature is a constant source of inspiration for engineers and scientists through its simple, effective, and elegant solutions to many complex problems. Smart materials and soft robotics have been seen to be particularly well suited for developing biomimetic devices and are active fields of research. In this study, the design, modeling, and optimization of a new biomimetic soft robot is described. Preliminary work was made in the modeling of a biomimetic robot based on the locomotion and kinematics of jellyfish. Modifications were made to the governing equations for jellyfish locomotion that accounted for geometric differences between biology and the robotic …

Numerical Study Of Biopolymer Implants For Distal Femoral Condyles– Finite Element Simulations, Luke Olsen

UNLV Theses, Dissertations, Professional Papers, and Capstones

Approximately 12% of the adult population in the United States is affected by

Osteoarthritis (OA) [1, 2]. Because of this, OA is the considered the most chronic degenerative joint disease, and is subject to continuous research into treatment. OA mainly manifests itself by degrading the articular cartilage in joints, such as the knee, and can eventually lead to complete loss of cartilage and potentially bone damage, leading to pain and discomfort for the patient [3]. For severe OA, the most common treatment is total knee arthroplasty (TKA) [4]. This procedure includes removing portions of the femur and tibia, and replacing …

Ozone Removal Efficiency And Surface Analysis Of Green And White Roof Hvac Filters, Omed A. Abbass, David Sailor, Elliott T. Gall

Mechanical and Materials Engineering Faculty Publications and Presentations

Heating, ventilation, and air-conditioning ( HVAC ) system filters from a commercial building were tested for their ability to remove ozone from intake air. Filters were taken from rooftop HVAC systems installed for two months: one located on a white membrane roof and the other on a vegetated green roof. One new, unused filter sample was tested as a reference. Samples from these filters were exposed to ozonated air streams at 40 and 120 ppb and relative humidity levels of 30% and 70%. Filter surfaces were analyzed with a scanning electron microscope to observe the structure and composition of the …

Design & Delivery Of Automated Winston-Lutz Test For Isocentric & Off-Axis Delivery Stability Utilizing Truebeam Developer Mode & Electronic Portal Imaging Device, Mahmoud Mohammad Yaqoub

UNLV Theses, Dissertations, Professional Papers, and Capstones

The uncertainties in treatment delivery cannot be ignored in radiation therapy. Thus, the quality assurance QA tests are very important task of the medical physicist in clinical practice. Assuring the coincidence between the mechanical isocenter of the Linear Accelerator (LINAC) and its radiation beams isocenter is one of the most important qualities need to be tested, and the Winston Lust (WL) test is the

most popular technique to perform this task, especially for the treatment modalities which need high precision in beam delivery such as the stereotactic radiosurgery/stereotactic body radiotherapy (SRS/SBRT). The linear accelerator-based SRS/SBRT is a well-established method in …

Development And Optimization Of Alumina Fine Fibers Utilizing A Centrifugal Spinning Process, Mandana Akia, Dulce Capitanachi, Misael E. Martinez, Carlos Hernandez, Hector De Santiago, Yuanbing Mao, Karen Lozano

Mechanical Engineering Faculty Publications

Highlights

• Successful synthesis of AIP/PVA composite fibers using Forcespinning® techniques.

• Optimization of the operating parameters applying response surface methodology (RSM).

• Fabrication of mesostructured gamma alumina and highly crystalline alpha alumina fine fibers.

Abstract

Aluminum isopropoxide and poly(vinylalcohol) fine fibers were successfully fabricated and optimized utilizing the response surface methodology. The optimized composite fibers showed mean fiber diameter of 304 nm. The fiber samples were calcined at different temperatures to attain both gamma and alpha phases of alumina. Various characterization methods including scanning electron microscopy, thermogravimetric analysis, x-ray diffraction and nitrogen adsorption/desorption analysis were conducted. The BET analysis …

Application Of Metabolic Modeling And Machine Learning For Investigating Microbial Systems, Ni Wan

McKelvey School of Engineering Graduate Student Theses & Dissertations

Metabolic modeling is an important tool to interpret the comprehensive cell metabolism and dynamic relationship between substrates and biomass/bioproducts. Genome-scale flux balance model and 13C-metabolic flux analysis are metabolic models which can reveal the theoretical yield and central carbon metabolism under various environmental conditions. Kinetic model is able to capture the complex principles between the change of biomass growth and bioproducts accumulation with the time series. Machine learning model is a data driven approach to reveal fermentation behavior and further predict cell performance under complex circumstances. In my PhD study, modeling analysis and machine learning method have been used to …

Thermal Fluid Models Of A Hydrogel Delivery System For Pancreatic Cancer Treatment, Nesrine Bouhrira

Theses and Dissertations

Pancreatic cancer is one of the most devastating cancers with low survival rates. This disease is difficult to detect due to the pancreas's location deep within the body. Therefore, diagnoses are often made in the later stages, making treatment options more limited and difficult. It has been hypothesized that direct injection into the tumor would enhance drug effectivenes. Therefore, we examined the use of endoscopic ultrasound (EUS) combined with a fine needle injection to deliver a drug-eluding thermosensitive hydrogel directly into the tumor. Unfortunately normal body temperatures surrounding the EUS can warm the hydrogel drug combination beyond its phase transition …

A Study Of Light-Matter Interaction In Nanopatterned Arrays And Biosensing Applications, Mohammad Waliullah

Student Theses and Dissertations

Food fraud and adulteration issue is persistent everywhere in today’s world. Identification of the seafood and meat species correctly, swiftly and economically is a necessity to fight this issue. Every species has its unique DNA. Therefore, identification of DNA will lead to identification of species. Before identification, DNA must be amplified to facilitate analysis. The traditional methods for both amplification and identification of DNA require sophisticated laboratory, trained personnel, high cost and long time. In case of amplification, choosing Recombinase Polymerase Amplification (RPA) method over traditional barcoding method can reduce these problems. In case of identification, fabrication of a novel …

Digital Enhancement Of Analog Measurement Systems For Temperature Compensation Of Strain Gages, Islombek Karimov

Electrical Engineering Theses

Generally known temperature compensation techniques for strain gages (like the use of a dummy gage or the implementation of half- and full-bridge configurations) are not applicable to all strain-measurement situations and cannot fully compensate for all sources of error. Digital Enhancement of Analog Measurement Systems presents a universal method of corrections for these effects in which temperature is measured independently of other variables and ex post facto corrections are computed and applied to digitized readings of the analog measurement system.

A single, linear-pattern strain gage, self-temperature-compensated for steel 1018, has been utilized in a quarter-bridge to measure tensile strain in …

Finite Element Analysis Of A Guideway For Automated Transit Networks, Issac Gendler

McNair Research Journal SJSU

An asymmetric beam currently being utilized in a solar powered automated transit system was analyzed for its deflections, stresses, and angle of twist. Finite element analysis (FEA) with ANSYS was used in conjunction with hand calculations from beam theory to determine the response of the guideway to loading anticipated in normal operation. An iterative approach was used for modeling the system, where the geometry was taken from a simplified case and progressed in complexity until the original model was duplicated. After analysis, the deflections, stresses, and angles of twist were found to be within suitable ranges for a suspended transportation …

Design And Synthesis Of Novel Nanometallic Catalysts And Electrode Materials For Green Fuel Cells, Jing Zhang

Graduate Dissertations and Theses

The United Nations formally adopted 17 sustainable development goals (SDGs) at its 2015 summit. Many of these goals addressed issues such poverty, hunger, health, education, climate-change, gender equality, water, sanitation, energy, urbanization, environment and social justice. The seventh SDG seeks to ensure access to affordable, reliable, sustainable and modern energy for all. So among all renewable forms of energy, fuel cells with high efficiency have attracted a lot of attention recently. In particular, the direct ethanol fuel cells (DEFCs) and microbial fuel cells (MFCs) are significant due to their green fuel, less waste generated and environmental friendliness. Hence the overall …

Aligned Carbon Nanotube Arrays Bonded To Solid Graphite Substrates: Thermal Analysis For Future Device Cooling Applications, Betty T. Quinton, Levi Elston, James D. Scofield, Sharmila M. Mukhopadhyay

Mechanical and Materials Engineering Faculty Publications

Carbon nanotubes (CNTs) are known for high thermal conductivity and have potential use as nano-radiators or heat exchangers. This paper focuses on the thermal performance of carpet-like arrays of vertically aligned CNTs on solid graphite substrates with the idea of investigating their behavior as a function of carpet dimensions and predicting their performance as thermal interface material (TIM) for electronic device cooling. Vertically aligned CNTs were grown on highly oriented pyrolytic graphite (HOPG) substrate, which creates a robust and durable all-carbon hierarchical structure. The multi-layer thermal analysis approach using Netzsch laser flash analysis system was used to evaluate their performance …

Pedestrian Injury Severity Analysis In Motor Vehicle Crashes In Ohio, Majbah Uddin, Fahim Ahmed

Faculty Publications

According to the National Highway Traffic Safety Administration, 116 pedestrians were killed in motor vehicle crashes in Ohio in 2015. However, no study to date has analyzed crashes in Ohio in order to explore the factors contributing to the pedestrian injury severity resulting from motor vehicle crashes. This study fills this gap by investigating the crashes involving pedestrians exclusively in Ohio. This study uses the crash data from the Highway Safety Information System, from 2009 to 2013. The explanatory factors include the pedestrian, driver, vehicle, crash, and roadway characteristics. Both fixed- and random-parameters ordered probit models of injury severity (where …

Atmospheric Resiliency: Enhancing Environmental Air Quality Through Bio-Architecture, Francesca Boakye

Bachelor of Architecture Theses - 5th Year

The theory of purifying a city’s smog filled atmosphere by using green microalgae can be architecturally realized through a designed building envelope composed of multiple units of microalgae filled perforated panels. The nature of this project is bio-architectural. Precise execution of it relies on deep research in vehicular emission pollution in terms of molecular composition. This research will help identify the most prominent pollutant in the smog composition and match it to a species of algae that can completely process it during photosynthesis. In addition to air pollution research, research on algae typology, growth and environmental impact is also essential …

Research And Development Of Powder Brazing Filler Metals For Diamond Tools: A Review, Fei Long, Peng He, Dusan P. Sekulic

Mechanical Engineering Faculty Publications

Powder brazing filler metals (PBFMs) feature a number of comparative advantages. Among others, these include a low energy consumption, an accurate dosage, a good brazeability, a short production time, and a high production efficiency. These filler metals have been used in the aerospace, automobile, and electric appliances industries. The PBFMs are especially suitable for diamond tools bonding, which involves complex workpiece shapes and requires accurate dosage. The recent research of PBFMs for diamond tools is reviewed in this paper. The current applications are discussed. The CuSnTi and Ni-Cr-based PBFMs have been the two commonly used monolayer PBFMs. Thus, the bonding …

Study Of Near-Cup Droplet Breakup Of An Automative Electrostatic Rotary Bell (Esrb) Atomizer Using High-Speed Shadowgraph Imaging, Jacob E. Wilson, Stephen William Grib, Adnan Darwish Ahmad, Michael W. Renfro, Scott A. Adams, Ahmad Salaimeh

Mechanical Engineering Faculty Publications

Electrostatic Rotary bell (ESRB) atomizers are used as the dominant means of paint application by the automotive industry. They utilize the high rotational speed of a cup to induce primary atomization of a liquid along with shaping air to provide secondary atomization and transport. In order to better understand the fluid breakup mechanisms involved in this process, high-speed shadowgraph imaging was used to visualize the edge of a serrated rotary bell at speeds varying between 5000 and 12,000 RPM and with a water flow rate of 250 ccm. A multi-step image processing algorithm was developed to differentiate between ligaments and …

Analysis Of Surface Integrity In Machining Of Aisi 304 Stainless Steel Under Various Cooling And Cutting Conditions, F. Klocke, B. Döbbeler, S. Lung, S. Seelbach, Ibrahim S. Jawahir

Institute for Sustainable Manufacturing Faculty Publications

Recent studies have shown that machining under specific cooling and cutting conditions can be used to induce a nanocrystalline surface layer in the workspiece. This layer has beneficial properties, such as improved fatigue strength, wear resistance and tribological behavior. In machining, a promising approach for achieving grain refinement in the surface layer is the application of cryogenic cooling. The aim is to use the last step of the machining operation to induce the desired surface quality to save time-consuming and expensive post machining surface treatments. The material used in this study was AISI 304 stainless steel. This austenitic steel suffers …