Engineering Commons^™

Comparison Of Thermal Properties Of Laser Deposition And Traditional Welding Process Via Thermal Diffusivity Measurement, Yu Yang, Omoghene Osaze Obahor, Yaxin Bao, Todd E. Sparks, Jianzhong Ruan, Jacquelyn K. Stroble, Robert G. Landers, Joseph William Newkirk, Frank W. Liou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Laser deposition is an effective process for mold and die repair. In order to improve the part repair quality, the process impact on thermal diffusivity and thermal conductivity needs to be understood for laser deposited, welded and virgin H13. In this paper, H13 tool steel samples were made by laser deposition, welding and virgin H13 and then cut into pieces. Experiments were conducted to investigate the thermal diffusivity and conductivity. A laser flash method is used to test these samples. The future work and opportunities are also summarized.

Evaluation Of Mechanical Properties And Microstructure For Laser Deposition Process And Welding Process, Yaxin Bao, Jianzhong Ruan, Todd E. Sparks, Jambunathan Anand, Joseph William Newkirk, Frank W. Liou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Laser Aided Manufacturing Process (LAMP) can be applied to repair steel die/molds which are currently repaired using traditional welding process in industry. In order to fully understand the advantages of laser deposition repair process over traditional welded-repair process, the mechanical properties such as tensile strength and hardness of H13 tool steel samples produced by these two processes were investigated. The microstructure and fracture surface of the samples were analyzed using optical microscope and SEM (Scanning Electron Microscope). Moreover, depositions on substrates with different shapes were studied to evaluate the performance of LAMP on damaged parts with complicated geometric shape.

Freeze-Spray Processing Of Layered Ceramic Composites, Qiang Fu, Oratai Jongprateep, Ashlee Abbott, Fatih Dogan

Materials Science and Engineering Faculty Research & Creative Works

Thermal gradients and associated stresses are critical in designing with ceramic composites having low thermal conductivity. In order to reduce the stresses from thermal gradients, compositional gradients are employed in designing of composite structures. This study addresses development of freeze-spray process to fabricate layered ceramic structures with controlled layer thickness and microstructural development. The composites were processed by spraying of ceramic slurries with low binder content and relatively high solids loadings (up to 40 vol%) on a cooled substrate. The frozen parts were freeze-dried and sintered at elevated temperatures. The relationship between microstructural development and thermal expansion behavior of Al …

Method For Fabricating Nanostructured Solid Oxide Fuel Cells And Cell Components, Harlan U. Anderson, X.-D. Zhou, Wayne Huebner

Materials Science and Engineering Faculty Research & Creative Works

A method of fabricating a nanostructured solid oxide fuel cell includes dispersing ceria and doped ceria nanoparticles in a first colloidal solution, atomizing the first colloidal solution into a spray, depositing the spray onto a substrate to form a thin film electrolyte, dispersing a nanocomposite powder including ceria and CuO in the first solution, forming a second colloidal solution, atomizing the second colloidal solution into a second spray, and depositing the second spray over the thin film electrolyte as an interfacial layer.

Method Of Preparing A Solid Oxide Fuel Cell, Greg Hilmas, Dustin Beeaff

Materials Science and Engineering Faculty Research & Creative Works

A solid oxide fuel cell having a multichannel electrode architecture and method for preparing the same, the method including forming a first carbon laden composition, including a first thermoplastic binder, into a rod, applying a first zirconia laden composition, including a second thermoplastic binder, onto the rod to form a composite feed rod, extruding the composite feed rod to form a controlled geometry filament, bundling the extruded composite feed rod to form a multicellular feed rod, extruding the multicellular feed rod to form a multicellular rod, cutting the multicellular rod into multicellular discs, applying a zirconia laden material to one …

Inelastic Deformation Behavior Of La0.6sr0.4feo3 Perovskite, Nina Orlovskaya, Harlan U. Anderson, Mykola Brodnikovskyy, Mykola Lugovy, Michael John Reece

Materials Science and Engineering Faculty Research & Creative Works

Inelastic deformation behavior of the rhombohedral La_0.6Sr_0.4FeO₃ perovskite is reported. Such behavior is very similar to the ferroelastic deformation of LaCoO₃ or lead zirconate titanate perovskites, except that no twin structure was found to exist in La_0.6Sr_0.4FeO₃. the possible mechanisms responsible for such nonlinear deformation behavior are discussed. © 2006 American Institute of Physics.

High Temperature Heat Exchanger Project: Quarterly Progress Report April 1, 2006 Through June 30, 2006, Anthony Hechanova

Publications (NSTD)

Numerical Analyses of the Ceramatec Sulfuric Acid Decomposer. Comparisons with experiments for the Ceramatec sulfuric acid decomposer coupon with eight straight channels for four different geometries and four different flow rates were performed. All of the operation and boundary conditions for the calculations were the same as in the Ceramatec experiments. Good agreement was found. The overall pressure drop difference between calculations and experiments for most of the cases is within 10%.

Self-Assembly Of Nanoparticles In Photonic Crystal Cavities For Optoelectronic Devices, Geetha Thiruvengadam

Material Science and Engineering Theses - Archive

Photonic crystals (PhC) offer many advantages in optoelectronics field. The focus of this thesis is to investigate a self assembly process for the formation of thin film based one-dimensional PhC and the integration of nanoparticles with two-dimensional PhC. Nanoparticles like SiO2, TiO2, PolyStyrene, and PbSe (with different surface properties) were subjected to different experiments. Various techniques, such as spin coating, immersion technique, evaporation induced assembly technique, have been carried out by varying parameters like time, temperature, position of the substrate, etc.,. An optimized method for the fabrication of 1D PhC was found to be evaporation induced Self-Assembly method by varying …

Preparation And Characterization Of Doped Zinc Oxide, Yogeeswaran Ganesan

Material Science and Engineering Theses - Archive

Cathodic electrodeposition was used to prepare thin films of ZnO doped with Cd, from oxygenated KCl electrolyte containing ZnCl2 and CdCl2 in various molar ratios ranging from 0 mM to 5.0 mM each. Evidence for doping was obtained from X-ray powder diffraction, diffuse reflectance, chronopotentiometry, and X-ray photoelectron spectroscopy data. The Cd-doped ZnO samples showed a superior photoresponse relative to undoped ZnO. Cadmium- and indium-doped ZnO were prepared by combustion synthesis using CdCl2 and InCl3 as dopant precursors along with zinc nitrate and urea as the combustion mixture. The doped samples were compared and contrasted with undoped ZnO using scanning …

Application Of Chip-Level Emc In Automotive Product Design, Kuifeng Hu, H. Weng, Daryl G. Beetner, David Pommerenke, James L. Drewniak, K. Lavery, Jason Whiles

Electrical and Computer Engineering Faculty Research & Creative Works

Integrated circuits (ICs) are often the source of the high-frequency noise that drives electromagnetic emissions from electronic products. A case study is presented where emissions from a printed circuit board containing an automotive microcontroller are reduced significantly through analysis of the coupling mechanisms from the chip to the board and attached cables. Noise generated by the IC is explored through measurements in a semi-anechoic chamber and TEM cell, through near-field scans, and through modifications to the printed circuit board. Noise is driven by the IC through both power and I/O connections. Results show that a ferrite in series with I/O …

Numerical Modeling Of Concrete Masonry Walls Strengthened By Fiber Reinforced Polymers Under Lateral Loads, Mohamed Salama

Archived Theses and Dissertations

The use of fiber reinforced polymers (FRP) for the seismic retrofit of masonry walls is on the rise. Design formulae are available to estimate the lateral load capacity of the strengthened walls. However, recent experimental data from tests conducted on full scale concrete masonry walls under cyclic lateral loads have shown that these design capacities have not been reached because of the occurrence of other failure modes not accounted for in the design formulae. The limiting failure mode in all test samples referred to in this work was due to premature compression failure of the masonry units at the wall …

48th Rocky Mountain Conference On Analytical Chemistry

Rocky Mountain Conference on Magnetic Resonance

Final program, abstracts, and information about the 48th annual meeting of the Rocky Mountain Conference on Analytical Chemistry, co-endorsed by the Colorado Section of the American Chemical Society and the Rocky Mountain Section of the Society for Applied Spectroscopy. Held in Breckenridge, Colorado, July 23-27, 2006.

Dielectric Constant Of Particles Determined By Impedance Spectroscopy, Vladimir Petrovsky, Abhishek Manohar, Fatih Dogan

Materials Science and Engineering Faculty Research & Creative Works

Electrical characterization of slurries prepared by mixing dielectric powders with solvents can be used to estimate dielectric properties of the particles. In particular, dielectric constant of the particles can be calculated from effective dielectric constant of the slurry measured at high frequency by using the Lorentz-Lorenz or similar equations based on mixing rules. Unfortunately, this approach leads to high margin of errors in dielectric constant estimation and is very sensitive to any slurry nonidealities such as sedimentation or agglomeration of particles. Impedance spectroscopy techniques are introduced to measure dielectric properties of particles at different frequency ranges. Dielectric constant of strontium …

Engineering Students' Perceptions Of And Attitudes Towards Cheating, Donald D. Carpenter, Trevor S. Harding, Cynthia J. Finelli, Susan M. Montgomery, Honor J. Passow

Materials Engineering

Academic dishonesty has become a serious problem at institutions of higher learning. This is particularly true in engineering where, according to previous research, engineering undergraduates are among the most likely to cheat in college. To investigate this concern, the authors embarked on a research project whose goal was to develop a better understanding of what students and faculty perceive as cheating and to use this knowledge to help instructors and institutions increase the level of academic integrity among students. The primary instrument for this project was a seven-page survey that was administered to 643 engineering and pre-engineering undergraduates at eleven …

Creep Behavior Of Linear Low-Density Polyethylene Films, Y B. Unigovski, A L. Bobovitch, E M. Gutman

Journal of Metals, Materials and Minerals

The Creep of biaxially-orientated linear low-density polyethylene (LLDPE) non-crosslinked and crosslinked with β-irradiation was studied as a function of the draw ratio and irradiation dose. The creep results have shown an increase in the creep strain after the polymer irradiation with a dose below 4 Megarad (MR) in comparison with a non-irradiated film. This increase corresponds to the disorientation in the amorphous phase, which takes place as a result of the film heating during irradiation. This disorientation was demonstrated by differential scanning calorimetry (DSC) and X-ray analysis.

Kinetics Of Carbonisation, Microstructure And Properties Of Al-Al4c3 System Prepared By Mechanical Alloying, M Besterci

Journal of Metals, Materials and Minerals

The method of mechanical alloying process is described. Carbon transformation to carbide Al4C3 is characterised within different heat treatment schedules and nine commercial carbon powders are tested. The micromechanism of carbon incorporation into the metallic powder, and the compacting of it are described. The influence of dispersed carbides on mechanical properties is evaluated together with the influence of deformation on microstructure and properties.

Drawing Quality Steel Sheet Under Tension And Bending Condition, M Mihaliková, M Buršák

Journal of Metals, Materials and Minerals

The paper analyzes the influence of the loading rate in the interval from 1 to 1000 mm/min on the mechanical properties of drawing quality steel sheet with the gauge of 1 mm, used for the manufacturing of automotive parts, under tension and bending conditions. It describes the aspects of material characteristics under tension and bending conditions, while bending tests were made on notched specimens (a modified impact bending test). The paper presents knowledge that using a modified notch toughness test. It is possible to achieve the pressability (formability) characteristics corresponding to dynamic strain rates even under the static loading.

Properties Of Collagen/Chitosan Scaffolds For Skin Tissue Engineering, C Tangsadthakun, S Kanokpanont, N Sanchavanakit, T Banaprasert, S Damrongsakkul

Journal of Metals, Materials and Minerals

Biopolymer blends between collagen and chitosan have the potential to produce cell scaffolds with biocompatible properties. In this study, porous scaffolds were fabricated by freeze drying the solution of collagen and chitosan and crosslinked by dehydrothermal treatment (DHT). Various types of scaffolds were prepared by varying compositions of collagen and chitosan. The scaffolds were fully characterized by Fourier transform infrared (FT-IR) spectroscopy. The results proved that collagen and chitosan scaffolds in all blending compositions contained only physical but not chemical interaction in molecular level. The compressive modulus from a universal mechanical testing machine decreased with increasing the compositions of chitosan. …

Multilayered Systems Of Nanostructured Tib2 Thin Films And Its Mechanical Properties, N Panich, P Wangyao, S Hannongbua, P Sricharoenchai, S Sun

Journal of Metals, Materials and Minerals

This study focuses on the development of single and multilayer TiB2 coatings with Ti interlayer with the aim of improving the mechanical integrity of the coating-substrate system. The nanostructured TiB2 thin films and multilayered coatings were deposited on high speed steel substrates by magnetron sputtering. The resultant coating systems were evaluated with respect to microstructure, fractured cross-section and fundamental properties such as cross-sectioned fracture, surface roughness, hardness, modulus and coating adhesion to the substrate. It was found that the adhesion strength of TiB2 coating to HSS substrate could be significantly enhanced in the multilayer system, and by a proper combination …

The Relationship Between Reheat-Treatment And Hardness Behaviour Of Cast Nickel Superalloy, Gtd-111, P Wangyao, V Krongtong, P Tuengsook, W Hormkrajai, N Panich

Journal of Metals, Materials and Minerals

he microstructure of cast polycrystalline nickel base superalloy, GTD-111, operated for long-term services were investigated by SEM after different re-heat-treatment conditions. It was found that the exposed specimen after long-term service could be recovered in some extent by re-solution treatment followed by two-step aging treatment. The obtained dispersed precipitation of gamma prime particles was more uniform than those of the long-term exposed microstructure. The results showed that the couple of the lower (1125°C) and/or higher (1175°C) solution annealing temperatures resulted in less total volume fraction of coarse gamma prime precipitates and less homogeneous distribution in microstructure than the medium (1150°C) …

X-Ray Photoelectron Spectroscopic Studies Of Dolomite Surfaces Exposed To Undersaturated And Supersaturated Aqueous Solutions, Xiaoming Hu, Pratik Joshi, Sharmila M. Mukhopadhyay, Steven R. Higgins

Mechanical and Materials Engineering Faculty Publications

Cleaved surfaces of dolomite were studied using ex-situ X-ray photoelectron spectroscopy (XPS) following exposure of the surfaces to various experimental conditions. Dolomite samples exposed to air, to a highly undersaturated solution (0.1 M NaCl, pH = 9), and to solution with a supersaturation (-Delta mu/kT) of 5.5 (pH = 9) were investigated with semiquantitative methods of analysis to ascertain the degree of non-stoichiometry resulting at the dolomite surface from reactive conditions. It was found that the dolomite cleavage surface in undersaturated solution was not altered significantly from the stoichiometric surface termination. The composition of the cleaved surface after exposure to …

Comparison Of Gelatin And Collagen Scaffolds For Fibroblast Cell Culture, J Ratanavaraporn, S Damrongsakkul, N Sanchavanakit, T Banaprasert, S Kanokpanont

Journal of Metals, Materials and Minerals

Gelatin and collagen were used to produce the scaffold for fibroblast cell culture. The properties of scaffolds obtained from type A and type B gelatin were compared to scaffold obtained from collagen, which is widely used in skin substitute. Porous scaffolds were prepared by freeze drying and dehydrothermal (DHT) crosslinking method. DHT treatment time was performed at 24 and 48 h and the degree of crosslinking was determined by 2,4,6-trinitrobenzene sulphonic acid (TNBS). The morphology of scaffolds was investigated by scanning electron microscopy (SEM). The compressive modulus and swelling ratio of the scaffolds were reported. To confirm the applicability of …

Fractures Of As-Cast Low-Carbon Steels In The Plasticity Degradation Area At High Testing Temperatures, A Ševčík, J Ševčíková

Journal of Metals, Materials and Minerals

The work studies the fractures of low-carbon steels after tensile tests in a temperature interval from ca 1200°C, where a plasticity degradation takes place, up to the liquid phase formation temperature. Statistical analyses of the temperature dependence of the reduction of area were made with the aim to determine integral effects of the chemical composition on the plasticity course. In the plasticity degradation temperature area, intercrystalline fractures occur, which have several morphologies, even within the same steel grade. Besides typical intercrystalline fractures, a fine-grained, interdendritic fracture often occurs. A specific case is the failure of steels in the γ + …

Mechanical Properties Of Skin Wounds After Atropa Belladonna Application In Rats, T Toporcer, T Grendel, B Vidinský, P Gál, J Sabo, R Hudák

Journal of Metals, Materials and Minerals

Atropa belladonna is a topical agent used in the treatment of skin wounds in Slovak folk medicine. The aim of this study was to asses the effect of A. belladonna extract on wound tensile strength in Sprague-Dawley rats. Twenty four rats were randomly divided into 3 groups of 8 animals. Two symmetrical skin incisions were performed on the back of each animal and immediately sutured. In the 1st group A. belladonna extract was not applied and the group served as a control. The animals in the 2nd group were treated by daily application of A. Belladonna extract during the first …

Modified Vegetable Oil In Textile Finishing Applications, N Jiratumnukul, P Antarasane

Journal of Metals, Materials and Minerals

Water-repellent finishing is an important process in textile industries as well as other finishing processes. Coating on the fabric can be used to achieve a substantial water-repellent effect. Using polymeric coatings, however, provided some disadvantages in air and water vapour permeability causing undesirable feelings when wearing. Besides, the fabric treated with polymeric coatings will impart a stiffening appearance, which is undesirable. In this study, water repellents have been prepared from various vegetable oils with different amounts of saturation in fatty acid moiety. Vegetable oil was transesterified with an intermediate fluorinated compound to give modified fatty esters. These fatty esters were …

Sub-Surface Corrosion Research On Rock Bolt System, Perforated Ss Sheets And Steel Sets For The Yucca Mountain Repository — Quarterly Technical Report No. 8, Dhanesh Chandra, Jaak J.K. Daemen

Publications (YM)

This report shows the work done for this period, in accordance to cooperative agreement of University of Nevada system for the Task 019 “Subsurface Corrosion Research on Rock Bolt System, Perforated SS Sheets and Steel Sets for the Yucca Mountain Repository”, the overall objective of which is to conduct corrosion research and predict the durability of rock-bolts and other underground metallic roof supports. We are performing oxidation tests using Thermogravimetric Analyzer (TGA), and Potentiodynamic tests to determine the corrosion rates of rock bolts, other support materials including bench mark materials. In this quarter, we have performed: Potentiodynamic tests were performed …

A Comparative Study Of Athletic Apparel Made From Cotton/Flax, Cotton/Polyester, And Polyester/Flax Blends, Elizabeth Skomra

Master's Theses and Doctoral Dissertations

The desired attributes of sports apparel garments are to have durability characteristics, such as tearing and tensile strength, and comfort characteristics, such as wicking, vapor transmission, and air permeability. Currently, most sports apparel is made from a blend of polyester or other synthetic fibers. Through examining the uniqueness of natural fibers, such as cotton and flax, the advantages and benefits of using a higher percentage of natural fibers when manufacturing comfortable and functional high performance athletic wear can be obtained.

Results from this study, regarding durability, determined that for both tearing and breaking strength, traditional sports apparel made with polyester/cotton …

Project-Based Introductory To Materials Engineering Modules On Biomaterials, Solid Oxide Fuel Cells, Non-Volatile Memory, And Fiber Reinforced Plastics, Stacy Gleixner, Elliot Douglas, Olivia Graeve

Faculty Publications

PRIME Modules, Project Based Resources for Introduction to Materials Engineering, are being developed that utilize modern materials science and engineering technologies and proven education methodologies of active learning and open ended projects. The modules are designed for use in a freshmen/ sophomore level Introduction to Materials Engineering course. This course is required by most engineering programs and is an ideal place to excite students about their engineering majors and expose them to real world engineering experiences. Currently four of the classroom modules have been developed and utilized in Introduction to Materials classes. There is a non-volatile memory module where students …

Curricula To Educate The 2020 Mse Engineering Professional: Simple But Powerful Changes In The Way That Mse Is Taught, Linda Vanasupa, Blair London, Katherine C. Chen, Richard Savage

Materials Engineering

National leaders in science and technology sectors speak in unison as they call for engineers who are not only technically competent in their fields, but who possess the abilities to communicate well, to work on teams, to apply systems thinking, to operate in the global business environment, to design within a greater set of constraints (environmental, health and safety, sustainability, economic, societal, political, manufacturability, and ethical). In short, our challenge is to educate an engineering professional who is far more sophisticated than the engineer of the 20^th century. Additionally, challenges brought on by the overuse of natural resources put …

Laying The Foundation For Nanoscience And Nanotechnology With An Introductory Module For High School Students, Maynard Valerie, Hsu Mathew, Katherine C. Chen, R. H. Chang

Materials Engineering

In response to the need to create a skilled workforce in nanotechnology and to excite young students with the wonders and potentials of science, the National Center for Learning and Teaching in Nanoscale Science and Engineering, is developing educational materials for grades 7 – 16. Learning theory and cutting-edge research are used in the development of modules on nanoscience and nanotechnology. This paper describes the rationale for such materials and describes an introductory module in which students are lead through a series of inquiry-based and hands-on activities, which lead to a design project. Its goal is to teach an underlying …