Open Access. Powered by Scholars. Published by Universities.®

Engineering Science and Materials Commons

Open Access. Powered by Scholars. Published by Universities.®

2009

Discipline
Institution
Keyword
Publication
Publication Type
File Type

Articles 61 - 90 of 120

Full-Text Articles in Engineering Science and Materials

Foundations Of Design Method Development, Sudhakar Teegavarapu May 2009

Foundations Of Design Method Development, Sudhakar Teegavarapu

All Dissertations

A systematic procedure for developing design methods, tools, and/or processes, referred to as meta-method, is proposed. It is hypothesized that design methods developed without following a systematic procedure are not effective and thus are not widely accepted by industry and academia likewise. The systematic framework provided by the meta-method will ensure 1) faster development of design methods, 2) enable tracking of requirements throughout the development process, 3) facilitate efficient exploration and selection of alternatives, 4) document the development process for future reuse, 5) help in testing and validation of design methods, and 6) bridge gap between multiple disciplines by ...


A Coupled Cfd-Kinetic Models For Cellulase Production In Airlift Reactor, Rachid Bannari, Abdelfettah Bannari, Brahim Selma, Pierre Proulx Apr 2009

A Coupled Cfd-Kinetic Models For Cellulase Production In Airlift Reactor, Rachid Bannari, Abdelfettah Bannari, Brahim Selma, Pierre Proulx

Rachid BANNARI

Cellulase production provides a catalyst for cellulose hydrolysis to glucose, to be used for eventual production of ethanol. The transport of reactants may influence the reaction rate remarkably, for the biological reaction, especially the enzymatic reaction, The transport behavior of the components in a biological system should be considered in the model. In this work, we propose a coupled model between hydrodynamics (twoPhaseEuler- Foam) and a kinetic model for batch and fed-batch cellulase enzyme production by T. reesei from cellulose/lactose substrate which is constructed from literature concepts and laboratory data. Good agreement is obtained between the results and experimental ...


Multiscale Modeling Of Impact On Heterogeneous Viscoelastic Solids With Evolving Microcracks, Flavio V. Souza Apr 2009

Multiscale Modeling Of Impact On Heterogeneous Viscoelastic Solids With Evolving Microcracks, Flavio V. Souza

Engineering Mechanics Dissertations & Theses

Multiscale computational techniques play a major role in solving problems related to viscoelastic composite materials due to the complexities inherent to these materials. In the present work, a numerical procedure for multiscale modeling of impact on heterogeneous viscoelastic solids containing evolving microcracks is proposed in which the (global scale) homogenized viscoelastic incremental constitutive equations have the same form as the local scale viscoelastic incremental constitutive equations, but the homogenized tangent constitutive tensor and the homogenized incremental history dependent stress tensor depend on the amount of damage accumulated at the local scale. Furthermore, the developed technique allows the computation of the ...


Acquisition Of A Sub-Micron Resolution X-Ray Computed Tomography System, Eric N. Landis, Andre Khalil Mar 2009

Acquisition Of A Sub-Micron Resolution X-Ray Computed Tomography System, Eric N. Landis, Andre Khalil

University of Maine Office of Research Administration: Grant Reports

The award will be used to purchase a laboratory scale x-ray computed tomography system capable of sub-micron spatial resolution. The system is capable of imaging the internal structure of a wide range of materials. This capability will initially be exploited to answer questions regarding the uptake of trace metals in the environment, bone mineral density, defects in micromachines, membrane and filter processes, artery roughness and fluid flow, and microstructure-property relationships for a variety of heterogeneous and functionally graded materials. All these fields will be aided by the parallel adaptation and implementation of sophisticated 3D image analysis routines to maximize the ...


Electric Energy Sector In Egypt: A Review, Dr. Adel A. Elbaset Mar 2009

Electric Energy Sector In Egypt: A Review, Dr. Adel A. Elbaset

Dr. Adel A. Elbaset

No abstract provided.


The Effect Of Silicon Content On Impact Toughness Of T91 Grade Steels, Ajit K. Roy, Pankaj Kumar, Debajyoti Maitra Mar 2009

The Effect Of Silicon Content On Impact Toughness Of T91 Grade Steels, Ajit K. Roy, Pankaj Kumar, Debajyoti Maitra

Mechanical Engineering Faculty Publications

The impact resistance of silicon (Si)-containing modified 9Cr-1Mo steels has been investigated within a temperature regime of -40 to 440°C using the Charpy method. The results indicate that the energies absorbed in fracturing the tested specimens were substantially lower at temperatures of -40, 25, and 75°C compared to those at elevated temperatures. Lower impact energies and higher ductile-to-brittle-transition-temperatures (DBTTs) were observed with the steels containing 1.5 and 1.9 wt.% Si. The steels containing higher Si levels exhibited both ductile and brittle failures at elevated temperatures. However, at lower temperatures, brittle failures characterized by cleavage and ...


Researches On Copper. History & Metallurgy, Fathi Habashi Feb 2009

Researches On Copper. History & Metallurgy, Fathi Habashi

Fathi Habashi

The present volume is a collection of selected papers dealing with the extractive metallurgy of copper published by the author and his coworkers. They are reproduced here in a facsimile edition in 240 pages. In addition ten new chapters were specially written in 150 pages. The book is fully illustrated by many colored pictures, flowsheets, and diagrams. It is hoped that it will be useful for students, engineers, chemists, geologists, and for research workers.


Non-Process And Chemical Free Offset Printing Plate, Bilge N. Altay, C. Koroglu, O. Yaman, C. Sahin Feb 2009

Non-Process And Chemical Free Offset Printing Plate, Bilge N. Altay, C. Koroglu, O. Yaman, C. Sahin

Bilge Nazli Altay

No abstract provided.


Gold. History, Metallurgy, Culture, Fathi Habashi Feb 2009

Gold. History, Metallurgy, Culture, Fathi Habashi

Fathi Habashi

Gold, the first metal used by man, has a special place among metals. It plays an important role in society and in world economics. It caused unprecedented mass migrations on three continents, and at least one war. It was responsible for creating many large cities, is highly prized, has been the inspiration of numerous myths, was the ultimate goal of alchemists, stored in the vaults of banks, widely on display in oriental bazaars, and is generously used in decorating churches and temples. The present volume is composed of two parts: a collection of selected papers published by the author on ...


Engineering Studies For Fluorescent Penetrant Inspection With A Focus On Developer Application Methods, Lisa Brasche, Rick Lopez, David J. Eisenmann, Keith Griffiths Feb 2009

Engineering Studies For Fluorescent Penetrant Inspection With A Focus On Developer Application Methods, Lisa Brasche, Rick Lopez, David J. Eisenmann, Keith Griffiths

Center for Nondestructive Evaluation Publications

Fluorescent penetrant inspection (FPI) is the most widely used global inspection method, playing a particularly important role in aviation. Given the contribution that reliable implementation of the FPI process can make to flight safety, the US Federal Aviation Administration (FAA) has funded a programme to assess the FPI parameters and their role in effective detection of typical flaws. Iowa State University’s Center for NDE (CNDE) has led a team that includes many industry partners from the aviation industry during this six-year programme. The industry partners have provided guidance and prioritisation input, and in many cases access to internal data ...


Optimal Design Of Wind-Pv-Diesel-Battery System Using Genetic Algorithm, Dr. Adel A. Elbaset Jan 2009

Optimal Design Of Wind-Pv-Diesel-Battery System Using Genetic Algorithm, Dr. Adel A. Elbaset

Dr. Adel A. Elbaset

The optimization of diesel generators (DGs) and renewable energy sources have to be done within a cost benefit, high reliability and environmentally friendly framework. Most of optimization method just consider only from economical point of view. This paper presents complete optimization method involving of cost, reliability and pollutant emission into optimization process. The reliability level is analyzed using basic probabilistic concept in order to find loss of load probability (LOLP). This value is then used to determine the customer damage cost due to electricity interruption. Meanwhile, CO2 emission as an indicator of pollution is calculated to determine the annual emission ...


Influence Of Ballast Conditions On Flexural Responses Of Railway Concrete Sleepers, Sakdirat Kaewunruen, Alex M. Remennikov Jan 2009

Influence Of Ballast Conditions On Flexural Responses Of Railway Concrete Sleepers, Sakdirat Kaewunruen, Alex M. Remennikov

Sakdirat Kaewunruen

Railway sleepers in track systems are usually modeled using the beam on elastic foundation theory. In reality, the sleeper-supported ballast is of highly frictional granular media but does not provide any tensile resistance. This paper presents a finite element model of a railway sleeper in a track system, taking into account the tensionless nature of the elastic support. The highlight of this paper is the effect of ballast distributions on the flexural responses of railway sleepers in track systems. Using a finite element package STRAND7, the finite element model updating of the concrete sleeper was earlier developed and validated against ...


Effect Of Non-Stationary Current Regimes On The Morphology Of Silver Electrodeposits, Zeljko J. Kamberovic Jan 2009

Effect Of Non-Stationary Current Regimes On The Morphology Of Silver Electrodeposits, Zeljko J. Kamberovic

Zeljko J Kamberovic

This work is concerned with the use of reverse current regimes in order to form small-grained and compact silver deposits during the electrorefining process. Several parameters were varied, i.e., i) anodic overpotential, ii) cathodic vs. anodic time ratio and iii) duration of the anodic pulse. After optimization of these parameters, phosphate ions were added and the electrolyte was stirred. The effects of a rise of the anodic overpotential on the grain sizes of the silver deposit and compactness were studied. Prolongation of the anodic time had a similar influence but with a decrease in current efficiency. An increase of ...


Chemistry And Metallurgy In The Great Empires, Fathi Habashi Jan 2009

Chemistry And Metallurgy In The Great Empires, Fathi Habashi

Fathi Habashi

It is remarkable that certain countries expand to become great empires then as time goes by they gradually decline while others rise. This book attempts to briefly trace the history of chemistry and metallurgy through the different empires that became at one time great and then faded away. In 272 pages 21.5 x 28 cm, the author outlines the inter-relation of chemistry, metallurgy, mining, and medicine, the idea of the divinity of kings and the formation of nations, and finally the rise and fall of the empires. He then covers the ancient and medieval empires, followed by the empires ...


Science, Technology, And Society, Fathi Habashi Jan 2009

Science, Technology, And Society, Fathi Habashi

Fathi Habashi

Science, technology, and society is a vast and complex question. It is discussed here from five points: social responsibility of scientists, migration and movement of scholars, philanthropy and its role in education and culture, enlightened despots and their influence on science and culture, and finally the social aspects of mining. The book is meant for the general reader but can benefit scientists as well. It is fully illustrated with colored pictures. It is hoped that it will serve as an introduction to this field to the young generation and inspire them to serve society.


Helical Force Flow: A New Engineering Mechanics Model For Biological Materials, Jeffery S. Thomas Jan 2009

Helical Force Flow: A New Engineering Mechanics Model For Biological Materials, Jeffery S. Thomas

Doctoral Dissertations

"The author has long speculated that the prevalence of helical structures in botany and zoology hints to an optimized pathway for force and/or energy transfer. His goal has been to realize an alternative approach to the standard stress analysis used in engineering in order to more efficiently and accurately deal with biological materials. Improved tools for these natural materials should in turn aid the design and analysis of engineered materials. Following the role of a navigator in leaf C. Levesque's book "Breakthrough Creativity", the author typically searches for ideas in a variety of places, including physics, materials science ...


Convergence, Adaptive Refinement, And Scaling In 1d Peridynamics, Florin Bobaru Ph.D., Mijia Yabg Ph.D., Leonardo F. Alves M.S., Stewart A. Silling Ph.D., Ebrahim Askari Ph.D., Jifeng Xu Ph.D. Jan 2009

Convergence, Adaptive Refinement, And Scaling In 1d Peridynamics, Florin Bobaru Ph.D., Mijia Yabg Ph.D., Leonardo F. Alves M.S., Stewart A. Silling Ph.D., Ebrahim Askari Ph.D., Jifeng Xu Ph.D.

Faculty Publications from the Department of Engineering Mechanics

We introduce here adaptive refinement algorithms for the non-local method peridynamics, which was proposed (in J. Mech. Phys. Solids 2000; 48:175–209) as a reformulation of classical elasticity for discontinuities and long-range forces. We use scaling of the micromodulus and horizon and discuss the particular features of adaptivity in peridynamics for which multiscale modeling and grid refinement are closely connected. We discuss three types of numerical convergence for peridynamics and obtain uniform convergence to the classical solutions of static and dynamic elasticity problems in 1D in the limit of the horizon going to zero. Continuous micromoduli lead to optimal ...


Identification Of Multiple Oscillation States Of Carbon Nanotube Tipped Cantilevers Interacting With Surfaces In Dynamic Atomic Force Microscopy, Mark Strus, Arvind Raman Jan 2009

Identification Of Multiple Oscillation States Of Carbon Nanotube Tipped Cantilevers Interacting With Surfaces In Dynamic Atomic Force Microscopy, Mark Strus, Arvind Raman

Birck and NCN Publications

Carbon nanotubes (CNTs) have gained increased interest in dynamic atomic force microscopy (dAFM) as sharp, flexible, conducting, nonreactive tips for high-resolution imaging, oxidation lithography, and electrostatic force microscopy. By means of theory and experiments we lay out a map of several distinct tapping mode AFM oscillation states for CNT tipped AFM cantilevers: namely, noncontact attractive regime oscillation, intermittent contact with CNT slipping or pinning, or permanent contact with the CNT in point or line contact with the surface while the cantilever oscillates with large amplitude. Each state represents fundamentally different origins of CNT-surface interactions, CNT tip-substrate dissipation, and phase contrast ...


Effects Of Build Orientation, Aging, And Pre-Conditioning On Mechanical Properties For Stereolithography-Manufactured Astm Type I Specimens Using A Design Of Experiments Approach, Karina Puebla Jan 2009

Effects Of Build Orientation, Aging, And Pre-Conditioning On Mechanical Properties For Stereolithography-Manufactured Astm Type I Specimens Using A Design Of Experiments Approach, Karina Puebla

Open Access Theses & Dissertations

With industry's growing focus on the rapid manufacturing (RM) of end-use products, rapid prototyping (RP) or layered manufacturing (LM) machines that were originally designed to build prototypes may now be required to build functional end-use products. To successfully accomplish the transition, the available materials utilized in RP must provide the performance required for RM. The specific technology used must also be capable of producing repeatable and reproducible parts in regards to mechanical and dimensional properties.

A design of experiments approach was performed to determine the effects of build orientation, aging, and pre-conditioning on the mechanical properties. To perform the ...


Exploring Poly(Ethylene Glycol) As A Suitable Material For Peripheral Nerve Regeneration Scaffolds Manufactured By Stereolithography, Nubia Zuverza Jan 2009

Exploring Poly(Ethylene Glycol) As A Suitable Material For Peripheral Nerve Regeneration Scaffolds Manufactured By Stereolithography, Nubia Zuverza

Open Access Theses & Dissertations

One of the challenges in tissue engineering is to have spatial and temporal control over the biological elements within a scaffold used to guide regeneration for example of transected nerves. Some of the physical and chemical characteristics to regulate include incorporation of bioactive domains and release of chemical signals. This study presents the use of stereolithography (SL) to incorporate localized domains for cell adhesion in addition to include releasable nerve growth factor (NGF) in the process of building poly(ethylene glycol)diacrylate (PEGda) hydrogel scaffolds. Besides providing sites for cell attachment, an ideal nerve guidance conduit (NGC) should be able ...


Characterization And Cytotoxic Assessment Of Ballistic Aerosolized Particulates For Tungsten Alloy Penetrators Interacting With Steel Targets, Brenda Ivette Machado Jan 2009

Characterization And Cytotoxic Assessment Of Ballistic Aerosolized Particulates For Tungsten Alloy Penetrators Interacting With Steel Targets, Brenda Ivette Machado

Open Access Theses & Dissertations

The aerosolized particulates produced during an impact of depleted uranium munitions can potentially contaminate extensive areas around the impact sites and cause a wide spectrum of civilian and military damage. Thus materials such as WHA have been prompted for consideration. The present research is concerned with the regular collection of aerosol particulates associated with ballistic WHA rod penetration into rolled homogeneous steel (RHA) or other related steel armor as armor plate sequences. Particulate size characterization via scanning electron microscopy (SEM) and transmission electron microscopy (TEM) along with chemical compositions via energy dispersive spectroscopy (EDS) were the focus of this research ...


Microstructural Characterization Of Overaged Gtd-111 Hp Turbine Buckets, Oscar Quintero Jan 2009

Microstructural Characterization Of Overaged Gtd-111 Hp Turbine Buckets, Oscar Quintero

Open Access Theses & Dissertations

Superalloys are metallic materials that exhibit excellent mechanical strength and creep resistance at high temperatures. They have good surface stability and are corrosion resistant. Superalloys are mostly used in the aerospace industry, gas turbine engines and blades (hot zones of gas turbines), and where extreme heat is encountered. The focus of this research was on the GTD-111 Ni-base superalloy, which is a General Electric (GE) proprietary superalloy mostly used in gas turbine blades with the form of high pressure or first stage buckets. This alloys features better mechanical properties, creep resistance, and a higher stress rupture temperature than the commonly ...


Additive Layer Manufacturing Of Ti-6al-4v By Electron Beam Melting From Powder Particles: Solid, Mesh And Foam Components Study, Sara M. Gaytan Jan 2009

Additive Layer Manufacturing Of Ti-6al-4v By Electron Beam Melting From Powder Particles: Solid, Mesh And Foam Components Study, Sara M. Gaytan

Open Access Theses & Dissertations

Additive Manufacturing by Electron Beam Melting Rapid Manufacturing is a technology that consists of the fabrication of a CAD design by melting powder particles in a layer by layer fashion. In this study, Ti-6Al-4V has been utilized to fabricate solid, mesh and foam components by EBM technologies. Powder analysis of Ti-6Al-4V was performed to obtain a better understanding of the porosity obtained by the system. After proper optimization of the machine, and porosity control, microstructural analysis was performed to the components already mentioned and correlated by transmission electron microscopy. Besides the microstructural analysis, tensile and hardness testing was performed to ...


Enhancing Reductive Dechlorination Of Chlorinated Ethenes And Ethanes In A Natural Treatment System, Caroline Burda Jan 2009

Enhancing Reductive Dechlorination Of Chlorinated Ethenes And Ethanes In A Natural Treatment System, Caroline Burda

LSU Master's Theses

Chlorinated solvent contamination continues to plague sites around the world. In many cases, lower chlorinated daughter products build up and remain in ground waters and soils. A Bio-Filter/Phytobed (BFP) system has been developed to replace a traditional pump and treat technology currently operating at the ReSolve Superfund site in North Dartmouth, MA. Pilot scale testing at the facility displayed a significant acclimation period prior to microbial dechlorination, as well as delayed degradation of chlorinated ethanes. Microcosm studies suggest that acidic conditions, possibly created by the peat mixture used to construct the bio-filter, inhibited bacterial growth. The neutralization of trench ...


Temperature Impact On Nitrification And Bacterial Growth Kinetics In Acclimating Recirculating Aquaculture Systems Biofilters, Milton Maada-Gomoh Saidu Jan 2009

Temperature Impact On Nitrification And Bacterial Growth Kinetics In Acclimating Recirculating Aquaculture Systems Biofilters, Milton Maada-Gomoh Saidu

LSU Doctoral Dissertations

This project assessed short-term temperature effects on total ammonia nitrogen (TAN) utilization rates in a batch laboratory-scale recirculating system. The tank system was designed for experiments on short term steady state and diurnal temperatures. A set of numerical models was developed to simulate observed results. The performance of the biofilters was determined with three tank replicates at fixed temperatures of 13, 20 and 300C; and at diurnal transient (sinusoidal) temperature regimes of (20 ± 30C; 30 ± 30C). Ammonia utilization rates and biofilter performance for beads acclimated at different temperatures regimes separated and mixed were also determined. Total ammonia utilization rates increased ...


Droplet Flows In Microchannels Using Lattice Boltzmann Method, Amit Gupta Jan 2009

Droplet Flows In Microchannels Using Lattice Boltzmann Method, Amit Gupta

Electronic Theses and Dissertations

Microelectromechanical systems (MEMS) have widespread applications in medical, electronical and mechanical devices. These devices are characterized by the smallest dimension which is at least one micrometer and utmost one millimeter. Rapid progress in the manufacture and utilization of these microdevices has been achieved in the last decade. Current manufacturing techniques of such devices and channels include surface silicon micromachining; bulk silicon micromachining; lithography; electrodeposition and plastic molding; and electrodischarge machining (EDM). In recent years, electrostatic, magnetic, electromagnetic and thermal actuators, valves, gears and diaphragms of dimensions of hundred microns or less have been fabricated successfully. Sensors have been manufactured that ...


Effect Of Sodium And Absorber Thickness On Cigs2 Thin Film Solar Cells, Parag Vasekar Jan 2009

Effect Of Sodium And Absorber Thickness On Cigs2 Thin Film Solar Cells, Parag Vasekar

Electronic Theses and Dissertations

Chalcopyrites are important contenders among solar cell technologies due to direct band gap and higher absorption coefficient. CuIn1-xGaxS2 (CIGS2) thin-film solar cells are of interest for space power applications because of near optimum bandgap of 1.5 eV for AM0 solar radiation outside the earth's atmosphere. The record efficiency of 11.99% has been achieved on a 2.7 µm CIGS2 thin film prepared by sulfurization at FSEC PV Materials Laboratory. Since CIGS2 films are typically grown in copper-rich regime, excess cuprous sulfide which helps in the formation of CIGS2 is etched away. This makes CIGS2 nearly stoichiometric. However ...


Study Of The Effects Of Sodium And Absorber Microstructure For The Development Of Cuin1-Xgaxse2-Ysy Thin Film Solar Cell Using An Alternative Selenium Precursor, Vinaykumar Hadagali Jan 2009

Study Of The Effects Of Sodium And Absorber Microstructure For The Development Of Cuin1-Xgaxse2-Ysy Thin Film Solar Cell Using An Alternative Selenium Precursor, Vinaykumar Hadagali

Electronic Theses and Dissertations

Thin film solar cells have the potential to be an important contributor to the world energy demand in the 21st century. CuInGaSe2 thin film solar cells have achieved the highest efficiency among all the thin film technologies. A steady progress has been made in the research and development of CuInSe2 based thin film solar cells. However, there are many issues that need to be addressed for the development of CuInSe2 based thin films solar cells. High price of PV modules has been a biggest factor impeding the growth of photovoltaic modules for terrestrial application. This thesis tries to address the ...


Design Of Sea Water Heat Exchanger For Miniature Vapor Compression Cycle, James Hughes Jan 2009

Design Of Sea Water Heat Exchanger For Miniature Vapor Compression Cycle, James Hughes

Electronic Theses and Dissertations

Recent advances in the development of miniature vapor compression cycle components have created unique opportunities for heating and cooling applications, specifically to human physiological requirements that arise in extreme environments. Diving in very cold water between 1.7 and 5°C requires active heating because passive thermal insulation has proven inadequate for long durations. To maintain diver mobility and cognitive performance, it is desirable to provide 250 to 300 W of heat from an untethered power source. The use of a miniature vapor compression cycle reduces the amount of power (batteries or fuel cell) that the diver must carry by ...


Observed Superspin-Glass Behavior In Ni0.5zn0.5fe2o4 Nanoparticles, Antony Adair Jan 2009

Observed Superspin-Glass Behavior In Ni0.5zn0.5fe2o4 Nanoparticles, Antony Adair

Open Access Theses & Dissertations

In this investigation we seek to identify the magnetic behavior of Ni0.5Zn0.5Fe2O4 nanoparticles though AC-susceptibility and DC-magnetization measurements. Powder x-ray diffraction was performed to determine the purity and average diameter ( ~ 9nm) of the particles. Aditionally, structure was confirmed by comparison through the International Centre for Diffraction Data's Powder Diffraction File [52] (PDF # 08-0234).

Zero-field cooled and field cooled DC magnetization measurements (bifurcation and blocking temperature), as well as M(H) hysteresis (below and above the blocking temperature) lead us to initially suggest that the material may in fact be superparamagnetic. However, further investigation of the real AC ...