Mechanical Engineering Commons^™

A Microfluidic Device For Impedance Spectroscopy, Ahmet Can Sabuncu

Mechanical & Aerospace Engineering Theses & Dissertations

Recently, microfluidics has become a versatile tool to investigate cellular biology and to build novel biomedical devices. Dielectric spectroscopy, on the other hand, allows non-invasive probing of biological cells. Information on the cell membrane, cytoplasm, and nucleus can be obtained by dielectric spectroscopy provided that appropriate tools are used in specific frequency ranges. This dissertation includes fabrication, characterization, and testing of a simple microfluidic device to measure cell dielectric properties. The dielectric measurements are performed on human T-cell leukemia (Jurkat), mouse melanoma (B16), mouse hepatoma (Hepa), and human costal chondrocyte cells. Dielectric measurements consist of measuring the complex impedance of …

Freight Transportation Analysis Comparison Of Short Sea Shipping To Conventional Transportation Modes, Vishwesh Vilas Parkhi

Mechanical & Aerospace Engineering Theses & Dissertations

Pollution due to transportation is one of the biggest concerns today. Freight transportation plays a significant role in this situation. Pollution can be reduced by minimizing the use of transport fuel. This can be achieved by selecting the most economical transport mode for long voyages for which fuel cost is one of the major costs. The model developed in this research helps in comparing the transport modes by evaluating cost per ton-mile. The three transportation modes of trucks, trains and Ro-Ro shipping vessels are considered in the model with very detailed costs associated with them. The major objective of this …

Methodology To Quantify Vertical Accelerations Of Planing Craft In Irregular Waves, Jennifer Suzanne Grimsley

Mechanical & Aerospace Engineering Theses & Dissertations

Planing craft operating in waves at high speeds can experience high, repetitive vertical accelerations that are random and nonlinear in relation to the sea condition. A proper understanding of vertical accelerations is critical to meet statistically based criteria for structural design, habitability, and equipment selection. Historically, it was assumed that planing craft vertical accelerations fit the Exponential distribution, and design methods adopted this conclusion. However, several published papers have raised doubts regarding the accuracy and validity of this Exponential distribution assumption.

The statistical behavior of planing craft vertical accelerations are examined for the Parent and Peak data sets from twenty-eight …

Development Of Sustainability Indicators For Products And Processes, Sundeep Bodapati

Mechanical & Aerospace Engineering Theses & Dissertations

Significant increase in industrialization is a leading cause for the depletion of global resources and changes in the earth's atmosphere due to global warming. There has been a major concern for the manufacturing industry to deal with the above problems and this had led the researchers to focus on the area of sustainability. Sustainable development aims for the future, which is characterized by the interaction of the economic, environment and society. To enable the manufacturing companies to measure sustainability performance, developing the metrics for sustainability is critical. The purpose of this thesis is to review the indicators published in the …

A Novel Piezoelectric Device With Dual Functions Of Studying Biological Soft Tissues, Avin A. Jamadagni

Mechanical & Aerospace Engineering Theses & Dissertations

This thesis presents the design of a novel piezoelectric device with dual functions of studying soft biological tissues. The device consists of a central circular plate and a set of flexural beams. The flexural beams are partially covered with piezoelectric film for integrated transduction. It can function as a force sensor for measuring the mechanical behavior of a tissue sample and a load applier for mimicking physiological loads experienced by the tissue sample in vivo, while the mechanical behavior can be visually observed under a microscope simultaneously. By combining the classic theories in solid mechanics and piezoelectricity, the performance of …

Prediction Of Shock Diamonds And Mach Disk In An Under-Expanded Air Jet, Praveen D. Malali

Mechanical & Aerospace Engineering Theses & Dissertations

The present study involves performing simulations, using the commercially available CFD code Fluent, to obtain under-expanded jet flow structures for different values of nozzle pressure ratio (NPR). A fluid flow domain comprised of a converging nozzle attached to a plenum chamber is discretized, using triangular cells, in the pre-processing software Gambit, companion software to Fluent. The test of grid independence is carried out by performing simulations for NPR value of 10 using three discretized flow domains, referred to as a mesh or a grid, with varying cell numbers. Two models, namely the inviscid compressible flow model, employing Euler equations, and …

Analytic Construction Of Periodic Orbits In The Restricted Three-Body Problem, Mohammed A. Ghazy

Mechanical & Aerospace Engineering Theses & Dissertations

This dissertation explores the analytical solution properties surrounding a nominal periodic orbit in two different planes, the plane of motion of the two primaries and a plane perpendicular to the line joining the two primaries, in the circular restricted three-body problem. Assuming motion can be maintained in the plane and motion of the third body is circular, Jacobi's integral equation can be analytically integrated, yielding a closed-form expression for the period and path expressed with elliptic integral and elliptic function theory. In this case, the third body traverses a circular path with nonuniform speed. In a strict sense, the in-plane …

Nanoindentation Creep Analysis For A Spherical Indenter, Phani K. Praturi

Mechanical & Aerospace Engineering Theses & Dissertations

The purpose of this work is to determine the strain rate sensitivity of the hardness in indentation creep and to investigate the relationship between the strain rate sensitivity of the hardness vH and the strain rate sensitivity of the flow stress vCT. A finite element model of nanoindentation creep was constructed and a parametric analysis was performed using Abaqus/Standard analysis software. It is found that the ratio vH / vCT does not maintain a unique relation with HIE• and varies with the increase in the ratio of depth of penetration to the radius of the indenter a/ R . Simulations …

Turbulent Flow Studies Of A Scaled Model Of A Large Mining Truck - Computations And Experiment, Wayne Randolph Sexton

Mechanical & Aerospace Engineering Theses & Dissertations

Modern mining operations are highly reliant on the amount of material that can be removed from the earth, transported to processing, and then processed. The companies that design and build mining dump trucks concentrate on improving the material payload capacity. Currently, the largest trucks are 400ton-class trucks. The design of these large mining dump trucks certainly does not stem from aerodynamics, but rather, from functionality and payload As a result, the shear size and asymmetric functional design creates interesting turbulent wakes on, around, and behind these trucks. This research focuses on the turbulent flow behind the truck. Computational Fluid Dynamic …

Analysis Of Wake Vortices Of A Medium Range Twin-Propeller Military Cargo Aircraft Using Statistically Designed Experiments, Burhan Sahin

Mechanical & Aerospace Engineering Theses & Dissertations

An experimental study was initiated to analyze the trajectories of the streamwise vortices behind the wing tip and flap of a medium range and propeller driven twin-engine military cargo aircraft. The model used for the experimental study was a generic, high wing and half model of a propeller driven aircraft and mounted within Old Dominion University's Low Speed Wind Tunnel where the wind tunnel flow speed was set to constant value of 9 m/sec. The main purpose of the study was to reach regression models for the motion and vorticity strength of both vortices under varying factors such as angle …

A Job-Shop Scheduling Model Using Genetic Algorithm And Giffler Thompson Approach, Nikhil Deepak Bumb

Mechanical & Aerospace Engineering Theses & Dissertations

The major objective of this thesis topic is to study the challenging research subject of job shop scheduling with the intent of optimizing the makespan. The job - shop scheduling problem is one of the hardest combinatorial optimization problems. The main aim of scheduling is an efficient allocation of shared resources like machines, operators or both over time for competing activities.

This research focuses on developing a model for optimizing job shop scheduling problem using genetic algorithm and the Giffler Thompson (priority dispatching rule) technique. Considering different parameters, the model comes up with an appropriate way to schedule the tasks …

Indentation Creep Analysis For Self Similar Indenters, Sandeep V. Thube

Mechanical & Aerospace Engineering Theses & Dissertations

In indentation creep experiments, it is difficult to characterize the mechanical properties of small size specimens using conventional methods. This study uses finite element modeling to investigate rate-sensitive deformation of materials with different hardness and strain rate sensitivities for self similar indenter tip geometries. The simulation model is developed using commercially available finite element software Abaqus/Standard. Our study investigates the difference between strain rate sensitivity of hardness (vH) and of flow stress (vu) and their relation to the hardness/modulus ratio. It reveals that the commonly held assumption that vH = vu is violated except for materials with low hardness/modulus …

Capacity Improvement Of A Small-Scale Cryogenic System Using Exergy Analysis, Errol L. Yuksek

Mechanical & Aerospace Engineering Theses & Dissertations

There is a demand for reliable and cost-effective small-scale helium liquefiers and refrigerators with higher capacity and efficiency in universities, government, and industry. Among the most common of these small-scale cryogenic systems is the Linde model 1600 helium liquefier and refrigerator.

The goal of this study is to increase the capacity of the model 1600. To achieve this goal, this study focuses on reducing the irreversibilities of the model 1600's fin-tube heat exchangers (FTHXs). Modification of fin-tube passes is the most practical means by which to reduce FTHX irreversibilities. Expressions relating FTHX geometry to FTHX irreversibilities identify model 1600 heat …

Unplanned Maintenance Scheduling A Lean Application Using Group Technology And Adaptive Conflict Resolution, Manish Shashibhushan Mittal

Mechanical & Aerospace Engineering Theses & Dissertations

Historically, production of ships is based on Group Technology (GT) with product oriented work breakdown structure. Recent GT applications have been effectively adapted to ship maintenance operations. In this thesis we have developed a GT based classification and coding system for the three basic requirements for maintenance operations: personnel, resources and space.

Traditionally unplanned maintenance activities are executed as and when the resources are available. This thesis presents a method for planning and scheduling these jobs with many of the traditional Lean manufacturing principles first adapted appropriately and then applied to Lean Maintenance. This method begins with identifying the priority …

A Three Dimensional Numerical Investigation Of A Donor Material In Friction Stir Welding, Justin M. Rice

Mechanical & Aerospace Engineering Theses & Dissertations

Excessive tool wear generated during the plunge phase of Friction Stir Welding has slowed the pace of expanding the Friction Stir Welding process to hard materials such as steel. This research uses a finite element model of the Johnson-Cook material constitutive law to investigate the shear stresses, axial forces, and temperatures experienced by the tool and the workpiece during the plunge stage of Friction Stir Welding. The model in this research was developed using the commercially available finite element analysis software ABAQUS/Explicit and consists of both a deformable workpiece and a deformable tool. By implementing the concept of using a …

Stability Analysis, Modeling, Simulation And Experimental Testing Of An Ems Maglev System With Structural Flexibility, Aravind M. Hanasoge

Mechanical & Aerospace Engineering Theses & Dissertations

Vehicle-guideway interaction studies of Magnetically Levitated (Maglev) vehicles indicate that structural flexibility can adversely affect the overall stability and performance of such systems. This is one of the reasons why guideways are generally made very rigid. This in turn leads to increased cost of the overall system since guideway construction forms a significant portion of the overall cost. In this dissertation, the influence of structural flexibility on the stability of Electromagnetic Suspension (EMS) Maglev systems is studied. It is shown how inherently unstable and flexible structure EMS Maglev systems can achieve guaranteed stability by using collocated actuators and sensors, along …

Numerical/Experimental Investigation Of Plunge Stage And Effect Of Donor Material In Friction Stir Welding, Saptarshi Mandal

Mechanical & Aerospace Engineering Theses & Dissertations

Friction Stir Welding (FSW) was developed in 1991 as a robust solid-state joining technique that uses a specially shaped rotating tool to generate heat and plasticize material around the tool. The tool then mixes plasticized material along the joint line to produce the weld. Over the last decade, FSW has become increasingly popular for welding aluminum. The combination of attractive properties of the weld and cost-efficiency has led researchers to investigate the feasibility of using FSW for steel. One of the major impediments for using friction stir welding for harder materials such as steel is tool wear. It is well-documented …

Finite Element Model Of A Tennis Racket, Sayali Shashikant Kapatkar

Mechanical & Aerospace Engineering Theses & Dissertations

An explicit finite-element (FE) model of a tennis racket and string was produced in NASTRAN/PATRAN. MSC/NASTRAN is a general-purpose FEA program capable of solving a wide variety of engineering problems such as linear static analysis, static analysis with geometric and material with nonlinearities, transient analysis with geometric and material nonlinearities. A finite element racket model was used to study the engineering characteristics that affect the "sweet spot" of a te1mis racket. A similar model was simulated by creating a tennis racket, a tennis ball and a string-bed, and it was validated against MADYMO (Mathematical Dynamic Model) data.

The MADYMO validation …

Advanced Design And Performance Characterization Of A Micromachined Tuning-Fork Gyroscope With High Quality Factors, Shiva Krishna Durgam

Mechanical & Aerospace Engineering Theses & Dissertations

Over the past two decades, micromachined gyroscopes fabricated using MicroElectroMechanical Systems (MEMS) technology have attracted a great deal of attention from various industrial and military sectors due to their significant advantages over traditional bulky gyroscopes, including small size, batch fabrication, low power consumption, and low cost. Among the various micromachined gyroscopes developed so far, tuning-fork gyroscopes with integrated electrostatic transducers have been extremely attractive because of their significant advantages over other structural forms and other types of transducers., including larger proof mass, large vibration amplitude in the drive-mode, and relative ease of fabrication.

This thesis presents the advanced design and …

Selection Of Pressure Equation For Preliminary Planing Hull Design Using Modified Analytical Hierarchy Process, Pamela Sue Fergen

Mechanical & Aerospace Engineering Theses & Dissertations

In the early stages of design when data availability is limited, engineers often times rely upon experience and regression analysis to select the most suitable design equation among many competitive ones. This study presents an alternative that applies a modified Analytical Hierarchy Process (AHP) to select the most suitable design equation. The Analytical Hierarchy Process, a multi-criteria decision making method, has been utilized in the business and management world to collect and evaluate experts' opinions in order to arrive at a final decision. The Analytical Hierarchy Process employed here will treat each of the design equations as an expert and …

Simulation Based Six-Sigma Design For Service Industry, Shantanu Dhananjay Ghate

Mechanical & Aerospace Engineering Theses & Dissertations

The main purpose of this thesis was to develop the dental clinic design using six-sigma principles. Simulation software called Process Model^TM was used to build a primary layout of the clinic. Once the basic design was built, statistical analysis method like D.O.E (design of experiment) was used to generate the data based on different combinations of design parameters viz. number of hygienists, number of x-ray machines and waiting room capacity. These data were further analyzed using Contrast-Effect method, ANOVA and Regression Analysis. In order to incorporate the impact of random factors, Taguchi's methodology was applied. This lead to the …

Parameter Estimation Of The Arterial System, James Charles Carter Ii

Mechanical & Aerospace Engineering Theses & Dissertations

There are a number of disorders that originate from or involve faulty operation of the cardiovascular system. Diseases such as atherosclerosis, diabetes and hypertension can have a debilitating effect on blood flow. This makes the tools for simulating the effects of such diseases on blood flow important. Measures, such as pulse wave velocity, that are generated by models of the cardiovascular system can be important indicators of cardiac health. Although physically measurable, obtaining some parameters comes with a high cost and discomfort to the patient. Models can provide an assessment of many important parameters. The purpose of this project was …

Virtualization Of Physical Experiments Using Real-Time Data Generation From A Computational Fluid Dynamics Code, Kaustubh A. Dharwadkar

Mechanical & Aerospace Engineering Theses & Dissertations

This work presents a methodology for mapping physical experiments into real-time, web-based virtual experiments. The four broad elements included in the physical-to-virtual experiment transformation methodology are: (a) computer solution of conservation equations of mass and momentum to generate velocity and pressure (virtual) data that serve as the foundation for recreating the physical phenomenon in the virtual domain; (b) use of virtual pressure and velocity sensing devices to generate signals or readings from computed virtual data that can be observed and read on a computer screen; (c) use of visualization software such as Macromedia FLASH to create a highly interactive environment …

Development Of Comprehensive Agility Measurement Tool, Ameya Surendra Erande

Mechanical & Aerospace Engineering Theses & Dissertations

This research focuses on the development of Comprehensive Agility Measurement Tool. Industry independent use of such a tool would help enterprises benchmark their success in achieving agility.

Continuous improvement and modernization of manufacturing techniques around the globe have brought many mutations in manufacturing industry. Customer expectations and demands are behind the introduction of new paradigms such as mass production, lean, mass customization, agile and now internet-based manufacturing. Though lean was first coined with respect to manufacturing industry, soon it became applicable in all the industries based on its waste reduction and productivity improvement techniques. Lacking international competitiveness of US manufacturing …

A Markov Based Model For Maintenance And Repair Of Equipment, Deepa Jaishankar

Mechanical & Aerospace Engineering Theses & Dissertations

The failure repair process of a continuously operating device is studied in this research. Different cases that incorporate modeling of equipment deterioration, inspection, and maintenance for optimal maintenance policy are proposed. Markov processes are used to determine state probabilities, and the optimal value of the mean time to preventive maintenance is determined by maximizing the availability of the equipment with respect to the mean time preventive maintenance. The approach uses models that assume that equipment can fail due to both deterioration and random failures. Preventive maintenance can be performed from each working state to avoid deterioration failure. Economic effects are …

Development Of A Technique To Diagnose Subtalar Joint Instability, Ajaya Dhakal

Mechanical & Aerospace Engineering Theses & Dissertations

Most patients escape diagnosis of subtalar joint instability for years before treatment. Therefore, a clinically relevant technique to diagnose subtalar joint instability will improve its management. Towards this goal, a six degree of freedom positioning and loading device was developed to apply physiologic loads to the hindfoot. Because the ideal loading configuration to detect subtalar joint instability is unknown, the device was designed to apply rotational and translational forces simultaneously. Specifically, plantarflexion/dorsiflexion, inversion/eversion, and internal/external rotation can be applied individually or as coupled motions along with an anterior/posterior drawer. Kinematic data were collected from calcaneus, talus and tibia using a …

Failure Repair Model For A Device Using Minor And Major Maintenance Strategies, Hrishikesh Raman Phadke

Mechanical & Aerospace Engineering Theses & Dissertations

The major objective of this research was to study the maintenance decision process for systems with economic dependency. A probabilistic model was developed according to the proposed Markov model. After determining the maintenance cost through the markov models, we introduced the other costs associated with the device like operating cost and capital recovery cost, to get the total cost of all the activities involved in keeping the device. The optimal equivalent uniform cost can be found to occur at a particular number of life stages in the system. The nature of the equivalent uniform cost curve is dependent upon the …

Experimental Analysis And Modeling Validation Of A Knee Brace In Shock Mitigation, Manish Prakash Dhekane

Mechanical & Aerospace Engineering Theses & Dissertations

An experimental setup simulating the dynamic environment in a high sea state is developed for the lower extremities to study the mitigation of shock impact. A single degree of freedom machine is equipped with six linear induction motors to produce impact acceleration ranging from 0.5G to 4G. The experiments are carried out along the dummy leg by using two configurations, one without a knee brace and one with a knee brace. Force and acceleration data is collected using a data acquisition system.

To develop the analytical model of the same experimental setup, the knee brace and dummy leg were scanned …

Process Study For The Design Of Small-Scale 2 Kelvin Refrigeration Systems, Peter N. Knudsen

Mechanical & Aerospace Engineering Theses & Dissertations

Helium refrigeration at temperatures below 4.5-Kelvin (K), but greater than 0.8-K typically employ a sub-atmospheric process utilizing a vacuum pumping system. These types of helium refrigerators are of keen interest to present and future particle physics programs utilizing super-conducting magnet or radio-frequency technology. As such, there is a need for small scale 2-K helium refrigeration systems (i.e., those that operated below the lambda temperature) in small laboratories and test facilities at this time. This study establishes the key process parameter choices of flow ratio, heat-exchanger size, and supply pressure, and how they influence the overall system performance for various process …

Disassembly Planning And Costing Through Petri Net Approach, Chunhsi Lei

Mechanical & Aerospace Engineering Theses & Dissertations

In the current consumer oriented environment, many new products appear in the market almost on a daily basis. Lured by advertisements and tempted by new product features, customers are constantly purchasing newer products. Acquiring newer products for often leads to throwing out older ones, but it is a totally different story for manufacturers. They need to consider the best way to reuse a product both for economic purposes and for environmental protection. Considerations for them often include: how to minimize total disassembly cost, how to achieve the lowest total disassembly time at each processing step, and how to sort valuable …