Engineering Commons^™

Design And Validation Of An Experimental Setup To Study Single Phase Heat Transfer Enhancement Of Femtosecond Laser Processed Metallic Surfaces, Sarah Jane Wallis

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

In the present work, a single phase flow heat transfer experimental loop was designed with the intention of studying the effects of femtosecond laser surface processing (FLSP) on metallic surfaces with the specific goal of enhancing heat transfer in compact heat exchangers currently in use by NASA. This experimental setup went through two major design iterations which are detailed in this thesis. The first iteration consisted of a counterflow fluid-to-fluid heat exchanger, which measured overall heat transfer coefficients and pressure drops, where the overall heat transfer coefficient is defined in terms of the total thermal resistance to heat transfer between …

Anchoring And Stiffening Techniques For Portable Concrete Barriers, Surajkumar Bhakta

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Portable concrete barrier (PCB) systems are utilized on federal and state highways in circumstances such as placing adjacent to vertical drop-offs and in construction zones. PCB systems are most commonly used in a free-standing configuration, which are known to have relatively large deflections when impacted. Large deflections are undesirable when dealing with limited space. In order to allow PCBs to be used in space restricted locations, seven PCB anchoring and stiffening techniques were tested and evaluated as per Manual for Assessing Safety Hardware (MASH) testing standards. Results will allow the New Jersey Department of Transportation to update guidance for their …

Cam-Based Pose-Independent Counterweighting For Partial Body-Weight Support In Rehabilitation, Ashish Shinde

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

This thesis presents the design and testing of a body weight support system for gait training in a two-dimensional workspace. Extension of the system to a three-dimensional workspace is not within the scope of this thesis.

Gait dysfunctions are changes in normal walking patterns, often related to a disease or abnormality in different areas of the body. There are numerous body weight support (BWS) systems present in the market which are applied to rehabilitation scenarios in mobility recovery like in gait training. But most of these BWE systems are costly and generally are stationary devices. A major drawback of such …

Cyber-Physical System Characterization And Co-Regulation Of A Quadrotor Uas, Seth E. Doebbeling

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

An Unmanned Aircraft System (UAS) is a Cyber-Physical System (CPS) in which a host of real-time computational tasks contending for shared resources must be cooperatively managed to obtain mission objectives. Traditionally, control of the UAS is designed assuming a fixed, high sampling rate in order to maintain reliable performance and margins of stability. But emerging methods challenge this design by dynamically allocating resources to computational tasks, thereby affecting control and mission performance. To apply these emerging strategies, a characterization and understanding of the effects of timing on control and trajectory following performance is required. Going beyond traditional control evaluation techniques, …

Design And Experimentation Of Cable-Driven Platform Stabilization And Control Systems, Matthew Newman

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Agricultural researchers are constantly attempting to generate crops superior to those currently in use by the world. Whether this means creating crops with greater yield, crops that are more resilient to disease, or crops that can tolerate harsh environments with fewer failures, test plots of these experimental crops must be studied in real-world environments with minimal invasion to determine how they will perform in full-scale agricultural settings. To monitor these crops without interfering on their natural growth, a noninvasive sensor system has been implemented. This system, instituted by the College of Agricultural Sciences and Natural Resources at the University of …

Design And Experimentation Of Cable-Driven Platform Stabilization And Control Systems, Matthew Newman

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Agricultural researchers are constantly attempting to generate crops superior to those currently in use by the world. Whether this means creating crops with greater yield, crops that are more resilient to disease, or crops that can tolerate harsh environments with fewer failures, test plots of these experimental crops must be studied in real-world environments with minimal invasion to determine how they will perform in full-scale agricultural settings. To monitor these crops without interfering on their natural growth, a noninvasive sensor system has been implemented. This system, instituted by the College of Agricultural Sciences and Natural Resources at the University of …

Development Of The End-Effector Of A Cable-Driven Parallel Manipulator For Automated Crop Sensing, Iman Salafian

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

A four cable-driven parallel manipulator (4CDPM), consisting of sophisticated spectrometers and imagers, is under development for use in acquiring phenotypic and environmental data over an acre-sized maize field. This thesis presents the design, controls, and testing of two sub-systems in a 4CDPM: a Center of Mass Balance System (CMBS) and a Drop-Down System (DDS).

One of the factors that influences stability is the center of mass (COM) position of the end effector. An offset in COM can cause a pendulum effect or an undesired tilt angle. A center of mass balancing system is presented in this thesis to minimize the …

Application Of Dfx Methods To A Gait Rehabilitation System, Devin K. Elley

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Walking is an important physical activity that offers major health benefits for those who are able to perform the task. However, there are millions of people worldwide who have lost the ability to walk from physical accidents or a disease which limits the ability for them to use their legs. Often these patients use gait therapy to learn how to walk again. During this gait therapy, a physical therapist may use gait rehabilitation machines to assist the patient in learning to walk in a correct gait path.

Two gait rehabilitation machine iterations were designed to produce an effective rehabilitation machine …

On The Wetting States Of Low Melting Point Metal Galinstan And Wetting Characteristics Of 3-Dimensional Nanostructured Fractal Surfaces, Ethan Allan Davis

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Exergy, or the availability of energy for useful work, is a critical issue that must be addressed to accommodate growing energy demands of society. Increasing population and steady advancement of technology necessitates novel approaches to the management, conversion, and storage of energy. Per the Lawrence Livermore National Laboratory, approximately 60 percent of the energy used by the United States in 2015 was rejected as waste [1]; a large quantity of which can be assumed to be in the form of heat. Therefore, novel thermal management methods for waste heat are critical to increasing energy efficiency and sustainability in the future. …

Safer Sweep Auger Operation Using Robotics, Nathan A. Wulf

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

This thesis presents a remotely controlled robotic solution for those who must sometimes enter agriculturally confined spaces in attempts to assist with grain bin cleanout, particularly by manipulating the sweep auger. In 2015 alone, there were at least 47 documented incidents that occurred in agriculturally confined spaces, of which more than half were fatal. While there have been several advancements in the quality and effectiveness of sweep augers, there have been very few that offer the safety and adaptability of the robotic solution proposed. This robotic solution is a four-wheeled, skid-steering style robot with camera and lighting attachments that allow …

Peridynamic Models For Fatigue And Fracture In Isotropic And In Polycrystalline Materials, Guanfeng Zhang

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

To improve design and reliability, extensive efforts has been devoted to understanding damage and failure of materials and structures using numerical simulation, as a complement of theory and experiment. In this thesis, peridynamics is adopted to study fatigue and dynamic failure problems.

Fatigue is a major failure mode in engineering structures. Predicting fracture/failure under cyclic loading is a challenging problem. Classical model cannot directly be applied to problems with discontinuities. A peridynamic model is adopted in this work because of important advantages of peridynamics in allowing autonomous crack initiation and propagation. A recently proposed peridynamic fatigue crack model is considered …

Applications Of Femtosecond Laser Processed Metallic Surfaces: Leidenfrost Point And Thermal Stability Of Rare Earth Oxide Coatings, Anton Charles Hassebrook

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

In this thesis, micro/nano structured surfaces were created through the use of Femtosecond Laser Surface Processing (FLSP). In the first part of the thesis, an experimental investigation of the effects of droplet diameters and fluid properties on the Leidenfrost temperature of polished and nano/microstructured surfaces has been carried out. Leidenfrost experiments were conducted on a stainless steel 304 polished surface and a stainless steel surface which was processed by a femtosecond laser to form Above Surface Growth (ASG) nano/microstructures. Surface preparation resulted in a root mean square roughness (R_rms) of 4.8 µm and 0.04 µm on the laser …

Development Of Peritoneal Microbubble Oxygenation As An Extrapulmonary Treatment For Hypoxia, Nathan Legband

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Patients affected by a respiratory disease or injury experience a substantially impaired respiratory system and as a consequence are unable to obtain a sufficient amount of oxygen. Hypoxia can quickly result in developing permanent tissue damage or death. Currently, the medical methods of treating hypoxia are mechanical ventilation or extracorporeal membrane oxygenation. However, these treatments are ineffective in certain cases and possess significant additional risks including barotrauma, infection, hemorrhage, and thrombosis.

The extrapulmonary method of peritoneal oxygenation has been investigated by other research groups as a potential alternative to providing supplemental oxygen in hypoxic animals. In peritoneal oxygenation, the peritoneum, …

Near-Field Thermal Radiation For Solar Thermophotovoltaics And High Temperature Thermal Logic And Memory Applications, Mahmoud Elzouka

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

This dissertation investigates Near-Field Thermal Radiation (NFTR) applied to MEMS-based concentrated solar thermophotovoltaics (STPV) energy conversion and thermal memory and logics. NFTR is the exchange of thermal radiation energy at nano/microscale; when separation between the hot and cold objects is less than dominant radiation wavelength (~1 μm). NFTR is particularly of interest to the above applications due to its high rate of energy transfer, exceeding the blackbody limit by orders of magnitude, and its strong dependence on separation gap size, surface nano/microstructure and material properties.

Concentrated STPV system converts solar radiation to electricity using heat as an intermediary through a …

Design And Validation Of An In Vivo Long-Term Attachment Capsule Robot, Wanchuan Xie

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

The invention of capsule endoscopy (CE) made the non-invasive monitoring of the entire small bowel possible and became the primary means for diagnosing small bowel pathology. In the last decade, capsule robots have been transformed from diagnostic devices into a widely studied biomedical platform with the potential for active locomotion, drug delivery and therapeutic capabilities. To perform accurate on-site drug release and therapy, it is necessary for a capsule robot to be able to attach to the intestinal tissue and maintain its position long-term. Design challenges derive from the task of long-term mucosal adhesion which requires firm, quick-response attachment without …

Oxidation Of Ti2Alc In High Temperature Steam Environment, Ziyad M. Smoqi

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

High temperature oxidation of fuel cladding materials, during the loss of coolant accident (LOCA), is of utmost importance for next-generation nuclear energy systems. Ti₂AlC is a promising candidate material for nuclear applications due to its outstanding properties such as thermal stability at high temperatures, oxidation resistance in air, thermal shock resistance, low neutron absorption cross-section, and the resistance to irradiation-induced amorphization. In this research, high temperature steam oxidation experiments were conducted to evaluate the oxidation resistance of Ti₂AlC in LOCA conditions. After oxidation in 100% steam at 600 and 800˚C, the oxidation kinetics followed a parabolic …

Formation Of Mound-Like Multiscale Surface Structures On Titanium By Femtosecond Laser Processing, Edwin Peng, Alfred Tsubaki, Craig A. Zuhlke, Ryan Bell, Meiyu Wang, Dennis R. Alexander, George Gogos, Jeffrey E. Shield

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Surface Functionalization Technique • Femtosecond Laser Surface Processing (FLSP) • Utilize high power, femtosecond (10-15 s) laser pulses • Produce self-organized, multiscale surface micro/nanostructures • Diverse range of applicable substrates: semiconductors, metals, polymers, & composites

Why? • What are the different types of FLSP structures on Ti? • Physical evidence needed for FLSP formation models • Optimize FLSP of Ti for biomedical & other applications

How? • Obtain evidence of mound growth processes by examining underlying microstructure • Utilize dual beam Scanning Electron Microscope-Focused Ion Beam instrument to cross section surface structures & fabricate transmission electron microscopy samples