Engineering Commons^™

Effect Of Heat Treatment On Microstructure, Hardness & Superelasticity Of Severely Deformed Niti, Omar Bahy El-Din Mortagy

Archived Theses and Dissertations

No abstract provided.

Dynamic Networking Of Exemplars: Towards A Mechanical Design Visual Programming Language, Shashidhar Putti

All Theses

Developing mechanical engineering design automation applications using current day textual programming languages like C, C++ requires extensive programming skills. However, learning to program in these environments can be time consuming and often frustrating to mechanical engineers due to the use of complex textual constructs and syntax to represent an algorithm in a linear fashion. Further, these programming languages offer a poor visualization of the data and the data flow due to their textual nature. The use of graphical objects for programming makes visualization easier and also eliminates the need for linear representation of algorithms. This thesis initiates the development of …

Me-Em 2007 Annual Report, Department Of Mechanical Engineering-Engineering Mechanics, Michigan Technological University

Department of Mechanical and Aerospace Engineering Annual Reports

Table of Contents

• Research Expansion
• Research Groups
• Faculty & Staff
• Students
• Alumni
• Resources
• Graduates
• Publications

Microstructures And Viscoelastic Properties Of Anisotropic Magnetorheological Elastomers, Lin Chen

Articles

The microstructures and viscoelastic properties of anisotropic magnetorheological elastomers were investigated in this paper. The measurement results show that their mechanical properties are greatly dependent on the magnetic flux density applied in preparation. A finite-column model was proposed to describe the relations between the microstructures and the viscoelastic properties. The simulation results agree well with the experimental results.

Investigation On Magnetorheological Elastomers Based On Natural Rubber, Lin Chen

Articles

Magnetorheological Elastomers (MR Elastomers or MREs) are a kind of novel smart material, whose mechanical, electrical, magnetic properties are controllable under applied magnetic fields. They have attracted increasing attentions and broad application prospects. But conventional MREs are limited to wide applications because their MR effects and mechanical performances are not high enough. This paper aims to optimize the fabrication method and to fabricate good natural rubber based MREs with high modulus by investigating the influences of a variety of fabrication conditions on the MREs performances, such as matrix type, external magnetic flux density, and temperature, plasticizer and iron particles. Among …

Improved Hole-Injection Contact For Top-Emitting Polymeric Diodes, Juo-Hao Li, Jinsong Huang, Yang Yang

Department of Mechanical and Materials Engineering: Faculty Publications

In this letter, an efficient hole-injection contact was achieved for the top-emitting polymeric light-emitting diodes (PLEDs). The anode has a structure of metal/molybdenum oxide/ poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT:PSS). It has been found that hole injection was significantly improved by inserting a thin layer of MoO₃ between aluminum and PEDOT:PSS. An ultraviolet photoelectron spectroscopy (UPS) was used to investigate the change of work function, and photovoltaic measurement confirmed that the improved hole injection is due to the reduction of barrier height, resulted from the addition of transition metal oxide. PEDOT:PSS layer was found necessary in anode structure to further enhance the …

A Novel Processing Route For The Production Of Nanoparticulate Zinc Oxide, Declan Mccormack, Grainne Duffy, Suresh Pillai

Articles

Zinc oxide nanoparticles have been processed from a novel isophthalate
precursor. In contrast to those processed from an oxalate precursor, this
material exhibits three-dimensional, non-directional aggregation behaviour.
Such non-directional aggregation of uniaxial crystallites may allow for the
production of structures with a higher proportion of catalytically active
surfaces than can be prepared through conventional sol–gel methods. XRD,
FTIR, TEM and SEM were used to characterize the synthesized materials.
Zinc oxide particles synthesized by using isophthalic acid
(C6H4-1,3-(COOH)2) are found to be slightly smaller than the previously
reported materials prepared through chelation with oxalic acid
(H2C2O2·2H2O).

Influence Of Van Der Waals Forces On Increasing The Strength And Toughness In Dynamic Fracture Of Nanofibre Networks: A Peridynamic Approach, Florin Bobaru Ph.D.

Department of Engineering Mechanics: Faculty Publications

The peridynamic method is used here to analyse the effect of van der Waals forces on the mechanical behaviour and strength and toughness properties of three-dimensional nanofibre networks under imposed stretch deformation. The peridynamic formulation allows for a natural inclusion of long-range forces (such as van der Waals forces) by considering all interactions as ‘long-range’. We use van der Waals interactions only between different fibres and do not need to model individual atoms. Fracture is introduced at the microstructural (peridynamic bond) level for the microelastic type bonds, while van der Waals bonds can reform at any time. We conduct statistical …

Time-Economic Lifetime Assessment For High Performance Thermal Barrier Coating Systems, Marion Bartsch, Bernd Baufeld, S. Dalkilic, Iulian Mircea, K. Lambrinou, T. Leist, J. Yan, Anette M. Karlsson

Mechanical Engineering Faculty Publications

Strategies for time-economic lifetime assessment of thermal barrier coatings (TBC) in service are described and discussed on the basis of experimental results, achieved on material systems with coatings applied by electron beam physical vapour deposition. Service cycles for gas turbine blades have been simulated on specimens in thermo-mechanical fatigue tests, accelerating the fatigue processes by an increase of load frequency. Time dependent changes in the material system were imposed by a separate ageing, where the samples were pre-oxidized prior to the fatigue test. Results of thermo-mechanical fatigue tests on pre-aged and as-coated specimens gave evidence of interaction between fatigue and …

Optimal Control Of Production And Distribution In A Supply Chain System Operating Under A Jit Delivery Policy, Pablo Biswas

LSU Doctoral Dissertations

This research deals with a supply chain system where the production or manufacturing facility operates under a just-in-time (JIT) environment, and the facility consists of raw material suppliers, manufacturers, and retailers where inventory of raw materials, work-in-process, and finished goods are involved, respectively. This work considers that the production of finished goods in one cycle starts just after the production or uptime in preceding cycle to minimize the idle time of the facility. Considering this scenario, inventory models are developed for different delivery situations: (a) perfect matching condition where no finished good remains after the shipments and (b) imperfect matching …

Semantic Image Retrieval Using Relevance Feedback And Transaction Logs, Amin Shah-Hosseini

LSU Doctoral Dissertations

Due to the recent improvements in digital photography and storage capacity, storing large amounts of images has been made possible, and efficient means to retrieve images matching a user’s query are needed. Content-based Image Retrieval (CBIR) systems automatically extract image contents based on image features, i.e. color, texture, and shape. Relevance feedback methods are applied to CBIR to integrate users’ perceptions and reduce the gap between high-level image semantics and low-level image features. The precision of a CBIR system in retrieving semantically rich (complex) images is improved in this dissertation work by making advancements in three areas of a CBIR …

Development Of A Biomass Transducer For Automated Microalgal Bioreactors, Amar Shivaram Hegde

LSU Master's Theses

A highly sensitive miniaturized biomass transducer is necessary for continuous and reliable monitoring of the microalgal biomass in a computer controlled, automated microalgal bioreactor. Previous known methods to determine microalgal biomass applicable in these bioreactors are based on single wavelength turbidimetric or fluorescence. The objectives of this research were to (1) determine the light absorption characteristics of some commercially applicable microalgae in the electromagnetic wavelength range of 200-800 nm (2) design and construct a new miniaturized biomass transducer (3) process the transducer output to correlate with the biomass. Wavelength sensitivity analysis was conducted on the commercially important microalgal species - …

Electrodeposition Of Multilayered Nanostructures For Giant Magnetoresistance And Thermoelectric Applications, Despina Davis

LSU Doctoral Dissertations

The electrodeposition of novel materials such as multilayer nanotubes for giant magneto resistance (GMR) applications and bismuth telluride nanotubes for thermoelectric applications are presented in this dissertation. The motivation for the multilayer electrodeposition is the investigation of giant magnetoresistance (GMR), a change in the material resistance in an applied magnetic field as a consequence of antiferromagnetic coupling. The nanowire high aspect ratio geometry allows the measurement of GMR with the current applied perpendicular to the plane (CPP) of the multilayers, which has been theoretically identified as being larger than the GMR in the (CIP) configuration (current in plane of multilayers). …

Engineering A Photo-Control Mechanism For Rna Interference, Richard Andrew Blidner

LSU Doctoral Dissertations

RNA interference (RNAi) is a phenomenon in which RNA molecules elicit potent and sequence-specific post-transcriptional gene silencing. Nucleic acid chemical modifications have been incorporated to improve their pharmacological properties. Despite numerous developments in chemical modifications for increased stability, safety, and efficiency of these therapeutic agents, they still face challenges of spatial and temporal targeting. One potential targeting strategy uses photocaging techniques, which involves the covalent attachment of photolabile compounds to the effector NA species that blocks bioactivity until exposed to near UV-light. This work demonstrates that fully-2’-fluorinated nucleic acids (FNAs) can elicit RNAi and that these effectors are resistant to …

Processing Nano Graphene Plates (Ngps) And Ngp Nanocomposite, Yena Li

Browse all Theses and Dissertations

In recent years numerous efforts worldwide are addressing all aspects of the rapid developing field of nanocomposites. However, the most important fillers-- carbon nanotube and carbon nanofiber - are expensive. In this study, our efforts are aimed at bridging the gap in cost and properties by providing a systematic study of alternative nano materials -- nano graphene plate (NGP) and related composites. We fabricated nano graphene plates through the detailed study of raw materials, chemical treatment methods and nano particle dispersion methods. A series of thermal expansion experiments were conducted to investigate the best condition to expand acid treated graphite …

Comparative Characterization Of Superconducting Thin Films Fabricated By Different Techniques, Padma Prasuna S. Vemulakonda

Browse all Theses and Dissertations

The goal of this thesis is to compare the chemical and compositional profiles, grain structure and critical current densities of superconducting Yttrium Barium Copper Oxide(Y1Ba2Cu3O7-x or YBCO) layers grown by different competing techniques on a variety of substrates and buffer layers. The idea is to check if there can be variation of cationic ratios, impurities, possible diffusion of substrate/buffer layer atoms into the YBCO for different processing methods and microstructures. Pulsed Laser Deposition (PLD), Metal Organic Deposition (MOD) and Metal Organic Chemical Vapor Deposition (MOCVD) films on Ion Beam Assisted Deposited (IBAD)-textured buffer layers and, Rolling Assisted Biaxial textured substrate …

Oxidation Resistant Coatings On Microcelluar Carbon Foam Using Simple Scalable Techniques, Dakshinamurthy Sharma Nagalingam

Browse all Theses and Dissertations

Carbon foam has many applications in the fields of thermal management, net-shape composites and electronic cooling due to its porous structure, low density, electrical and thermal conductivities. However it is prone to oxidation at high temperatures in air. Whereas some previous studies have reported oxidation protective coatings on other carbon structures such as graphite parts and fibers, there is very limited work on foam. Moreover, earlier methods have used vapor phase techniques such as Plasma Vapor Deposition (PVD) and Chemical Vapor Deposition (CVD). There is no known study involving such coatings using simple scalable liquid phase method. This thesis reports …

Minute Doping Of Pulsed Laser Deposition Processed Y123 Thin Films With Tb, Ce, And Pr, Joseph William Kell

Browse all Theses and Dissertations

Three rare earth elements (Tb, Ce, and Pr) were chosen for the investigation into whether adding minute quantities (≤1 at%) of dopants could improve the film quality of YBa₂C ₃O_7-δ(Y123) thin films. The compositions studied are (Y_1-x,Re_x)Ba₂Cu₃O_7-δ (RE=Tb, Ce, Pr; x=0.1, 0.01, 0.001). Good quality thin films were produced by PLD and showed significant improvement to properties when exposed to a magnetic field. Ce and Pr (x=0.001) doped films showed modest improvement. However, the Tb doped system showed substantial improvement to J_c(H), with a …

Low Voltage And Fast Speed All-Polymeric Optocouplers, Yan Yao, Hsiang-Yu Chen, Jinsong Huang, Yang Yang

Department of Mechanical and Materials Engineering: Faculty Publications

An all-polymeric optocoupler has been demonstrated with a polymer light-emitting diode (PLED) as the light source (input unit) and a polymer/fullerene photodiode (PD) as the detector (output unit). The electroluminescence (EL) peak of the PLED is 560 nm, and the entire EL spectrum is within the response range of the PD. The optocoupler can work at low driving voltages, 5 V on the PLED and 0 V on the PD. The output photocurrent increases linearly with input current, and the current density transfer ratio reaches 1.5%. The frequency response of the optocoupler is at 500 kHz. With comparable performance to …

Origin Of Photomultiplication In C60 Based Devices, Jinsong Huang, Yang Yang

Department of Mechanical and Materials Engineering: Faculty Publications

In this manuscript, the origin of the photomultiplication effect was studied in C₆₀ based devices by evaluating the wavelength dependent external and internal quantum efficiencies under various biases. The effect of materials with disordered structures on the photomultiplication effect was determined by intentionally integrating both ordered and disordered material structures into one organic solar cell device with a configuration of indium tin oxide/poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT:PSS)/pentacene/C₆₀ fullerene/bathocuproine (BCP)/Al. Our results show that both the disordered structure of C₆₀ and the charge trapping effect at the C₆₀ /PEDOT:PSS interface contribute to the photomultiplication effect. By studying the C60-only …

Deck-Mounted Steel Post Barrier System, John D. Reid, Ronald K. Faller, Jason A. Hascall

Department of Mechanical and Materials Engineering: Faculty Publications

An existing mountable safety barrier system, previously crash tested successfully on a wood bridge deck, was evaluated for use on a fiber reinforced plastic (FRP) bridge deck. In an attempt to avoid expensive full-scale crash testing, components of the existing system were evaluated using worst case conditions on two dynamic bogie crash tests and a series of computer simulations using nonlinear finite-element analysis. Simulation results closely approximated the physical results, with both displaying similar deformation, damage, and force levels. Both testing and simulation demonstrated that the barrier should function sufficiently if used on the FRP deck system. Further, the development …

Regional Mechanical Properties And Stress Analysis Of The Human Anterior Lens Capsule, Ryan M. Pedrigi, G. David, J. Dziezyc, J. D. Humphrey

Department of Mechanical and Materials Engineering: Faculty Publications

The lens capsule of the eye functions, in part, as a deformable support through which the ciliary body applies tractions that can alter lens curvature and corresponding refractive power during the process of accommodation. Although it has long been recognized that characterization of the mechanical properties of the lens capsule is fundamental to understanding this physiologic process as well as clinical interventions, prior data have been limited by one-dimensional testing of excised specimens despite the existence of multiaxial loading in vivo. In this paper, we employ a novel experimental approach to study in situ the regional, multiaxial mechanical behavior of …

A Scientific Foundation Of Collaborative Engineering, S. C.-Y. Lu, W. Elmaraghy, G. Schuh, R. Wilhelm

Department of Mechanical and Materials Engineering: Faculty Publications

Collaborative engineering is the practical application of collaboration sciences to the engineering domain. In today’s highly connected technology-driven economy, the production industry must rely on the best practices of collaborative engineering to stay competitive when designing, manufacturing, and operating complex machines, processes, and systems on a global scale. Despite its importance, collaborative engineering is currently more of a practiced art than a scientific discipline. A better understanding of how engineers should collaborate with all stakeholders to accomplish complex tasks that fulfill our increasing social responsibilities is a grand challenge. However, because we currently lack well-defined sciences of human collaboration, we …

Factors That Influence Visual Attention And Their Effects On Safety In Driving: An Eye Movement Tracking Approach, Larry Bargola Nabatilan

LSU Doctoral Dissertations

Statistics show that a high percentage of road related accidents are due to factors that cause impaired driving. Since information extraction in driving is predominantly a visual task, visual distraction and its implications are therefore important safety issues. The main objective of this research is to study some of the implications of demands to human’s attention and perception and how it affects performance of tasks such as driving. Specifically, the study aims to determine the changes that occur in the visual behavior of drivers with different levels of driving experience by tracking the movement of the eye; examine the effects …

Optimization For Software Release And Crash, Tanvir Khan

LSU Master's Theses

Software testing is a process to detect faults in the completeness and quality of developed computer software. Testing is a key process in assuring quality by identifying defects in software, and possibly fixing them, before it is delivered to end-users. A major decision to make during this software testing is, to determine whether to continue testing and eventually releasing the software, or when to stop the test and ‘crash’ it. Such a decision needs to be made to optimally balance the tradeoff between the cost of development and the reliability of the software. In this paper, a new optimal strategy …

Effect Of Hole Configurations On Film Cooling From Cylindrical Inclined Holes For The Application To Gas Turbine Blades, Yiping Lu

LSU Doctoral Dissertations

Film cooling is one of the cooling systems investigated for the application to gas turbine blades. Gas turbines use film cooling in addition to turbulated internal cooling to protect the blades outer surface from hot gases. The present study concentrates on the experimental and numerical investigation of film cooling performance for a row of cylindrical holes in a modern turbine blade. The adiabatic film effectiveness and the heat transfer coefficient are determined experimentally on a flat plate downstream of a row of inclined different geometries hole exit by using a single test transient IR thermography technique. The focus of this …

Aconitic Acid From Sugarcane: Production And Industrial Application, Nicolas Javier Gil Zapata

LSU Doctoral Dissertations

Trans aconitic acid (TAA) is the predominant organic acid in cane leaf matter (CLM) juice. Its concentration is three to six times higher than the level found in sugarcane stalks. The variation of composition in terms of total fermentable sugars (TFS), anions, and cations of the LCP85-384 sugarcane variety during 2003-2006 seasons, as well as the ripener (Polado-L®) effect were analyzed. TAA content ranged between 2.1-3.1 kg / t CLM. The TFS in CLM juice yielded a fermentation efficiency of 92%, four points lower than with sugar molasses. Liquid-liquid extraction (LLE), solid-liquid extraction and ion exchange were evaluated for the …

Emission Reduction In Small Displacement Diesel Engines Using Cooled Exhaust Gas Recirculation, Chris Simoson

All Theses

A reduced-order dynamic model is presented and experimentally validated to demonstrate the use of cooled exhaust gas recirculation to alleviate the tradeoff between nitric oxide reduction and performance preservation in a small displacement diesel engine. Exhaust gas recirculation (EGR) is an effective method for internal combustion engine oxides of nitrogen (NOx) reduction, but its thermal throttling diminishes power efficiency. The capacity to cool exhaust gases prior to merging with intake air may achieve the desired pollutant effect while minimizing engine performance losses.
Simulation and experimental results revealed significant NOx reductions throughout all testing scenarios using EGR, but also experienced a …

Single-Sided Crash Cushion System, John D. Reid, John R. Rohde, Dean L. Sicking

Department of Mechanical and Materials Engineering: Faculty Publications

A single-sided crash attenuation cushion system having an impact head and three stage energy absorption mechanism. The energy absorbing mechanism has a mandrel for deforming thin-walled tubes in a controlled collapse to absorb impact forces from a colliding vehicle. The third stage of the absorption mechanism includes an additional deformable compressible tube between the fixed-object hazard and the thin walled tubes.

Modeling Of The Transient Behavior Of Heat Pipes With Room-Temperature Working Fluids, Pascal Brocheny

All Dissertations

The heat pipe is a capillary-driven and two-phase flow device, capable of transporting and converting large amounts of energy with minimal losses. As a means of thermal management, uses of heat pipe technology not only include thermal control of satellites and spacecrafts in aerospace applications, but also the cooling of electronic components for ground applications. Recently, there has been a flourishing interest in exploring the use of heat pipe technology in the automotive field. However, in many thermal control applications, heat pipes using room-temperature working fluids, such as water or ammonia, with operating temperatures between 200 K (-73ºC) and 550 …