Engineering Commons^™

Method And System For Electronically Generating Random Answers, Stephen O. Bozzone, Bonnie Bachman

Economics Faculty Research & Creative Works

The invention concerns a method (300) and system (110) for electronically generating random responses in a portable electronic device (110). The method includes the steps of detecting (316) motion of the portable electronic device, in response to the detecting step, generating (318) the random response and outputting (320) the random response to a user of the portable electronic device. The method can further include the steps of prompting (312) the user to ask a question and following a predetermined time period after prompting the user to ask the question, prompting (314) the user to shake the portable electronic device. The …

College Of Engineering Senior Design Competition Fall 2005, University Of Nevada, Las Vegas

Fred and Harriet Cox Senior Design Competition Projects

Part of every UNLV engineering student’s academic experience, the senior design project stimulates engineering innovation and entrepreneurship. Each student in their senior year chooses, plans, designs and prototypes a product in this required element of the curriculum. A capstone to the student’s educational career, the senior design project encourages the student to use everything learned in the engineering program to create a practical, real world solution to an engineering challenge.

The senior design competition helps to focus the senior students in increasing the quality and potential for commercial application for their design projects. Judges from local industry evaluate the projects …

Ferroelectric Switch For Spin Injection, Mikhail Ye. Zhuravlev, Sitaram Jaswal, Evgeny Y. Tsymbal, Renat F. Sabirianov

Materials Research Science and Engineering Center: Faculty Publications

A method for the switching of the spin polarization of the electric current injected into a semiconductor is proposed, based on injecting spins from a diluted magnetic semiconductor through a ferroelectric tunnel barrier. We show that the reversal of the electric polarization of the ferroelectric results in a sizable change in the spin polarization of the injected current, thereby providing a two-state electrical control of this spintronic device. We also predict a possibility of switching of tunneling magnetoresistance in magnetic tunnel junctions with a ferroelectric barrier and coexistence of tunneling magnetoresistance and giant electroresistance effects in these multiferroic tunnel junctions.

Negative Spin Polarization And Large Tunneling Magnetoresistance In Epitaxial Co|Srtio3|Co Magnetic Tunnel Junctions, Julian P. Velev, Kirill D. Belashchenko, Derek A. Stewart, Mark Van Schilfgaarde, Sitaram Jaswal, Evgeny Y. Tsymbal

Materials Research Science and Engineering Center: Faculty Publications

We perform an ab initio study of spin-polarized tunneling in epitaxial Co|SrTiO₃|Co magnetic tunnel junctions with bcc Co(001) electrodes. We predict a large tunneling magnetoresistance in these junctions, originating from a mismatch in the majority- and minority-spin bands both in bulk bcc Co and at the Co|SrTiO₃ interface. The intricate complex band structure of SrTiO₃ enables efficient tunneling of the minority d electrons which causes the spin polarization of the Co|SrTiO₃ interface to be negative in agreement with experimental data. Our results indicate that epitaxial Co|SrTiO₃|Co magnetic tunnel junctions with bcc Co(001) electrodes …

High Temperature Heat Exchanger Project: Quarterly Progress Report July 1, 2005 Through September 30, 2005, Anthony Hechanova

Publications (NSTD)

Quarterly Collaboration Meeting. The University of California, Berkeley, hosted a UNLVRF HTHX Project quarterly meeting on September 12. The purpose of the meeting was to promote collaboration and communication among the UNLV Research Foundation partners. Collaborators discussed their research program plan and provided an update on their progress. The next meeting will be in December in Las Vegas, NV hosted by UNLV.

Work In Progress - An Investigation Into The Effect Of An Institutional Honor Code Policy On Academic Behavior, Donald D. Carpenter, Trevor S. Harding, Cynthia J. Finelli, Matthew Mayhew

Materials Engineering

Research indicates significant cheating at institutions of higher learning; however, evidence indicates that a well-designed and clearly-communicated campus honor code might have a mitigating effect. This is the impetus behind the implementation of an Academic Honor Code Policy at a private university beginning in the fall of 2004. This situation presented a unique opportunity to investigate the potential of an academic honor code to change the culture and behavior at a university. This investigation will involve conducting a longitudinal study on the academic habits of students as they progress through the curriculum and include students whose academic careers began under …

A Case Study On Research In Engineering Education: Designing, Testing, And Administering The Paces-2 Survey On Academic Integrity, Cynthia J. Finelli, Jamie L. Szwalek, Donald D. Carpenter, Trevor S. Harding

Materials Engineering

Most engineering educators excel at planning and conducting technical research in their field, but few are proficient doing this for a project in engineering education. Recently, however, there has been increased emphasis on conducting rigorous research in engineering education. This paper provides practical advice for planning and conducting such research. The authors use their long term project to predict academic dishonesty in engineering college students as a case study representing one approach to research in engineering education. In particular, the authors present the design, testing, and administration of a two-part survey instrument to collect information from college students about their …

The Ballet Model In Engineering Classes – What Works, What Doesn't, And What's New, Blair London, Lisa Deyo

Materials Engineering

Six different engineering courses were taught using aspects of the classical ballet instruction model in organization, teaching methods, and learning strategies. There was a strong focus on performance. The courses spanned sophomore to senior levels. Some aspects of the ballet model worked well: setting rules for the Sacred Space for learning, the beginning activity (“stretch”), the overall organization of the class session, communicating the known ideal, including historical background, and using demonstrations. Some aspects did not work (thus far): exams are not yet performances on stage, little practice or rehearsal occurs, little competition between students occurs, asking students questions in …

Plasma Deposition Of Spin Chucks To Reduce Contamination Of Silicon Wafers, Emir Gurer, Ed C. Lee, Richard Savage

Materials Engineering

An apparatus for delivering a fluidic media to a wafer includes a housing defining a process chamber. A fluidic media delivery member is coupled to the process chamber. A rotatable chuck is positioned in the process chamber. The rotatable chuck has a wafer support surface coated with a coating material. A vacuum supply line is coupled to the rotatable chuck.

Sub-Surface Corrosion Research On Rock Bolt System, Perforated Ss Sheets And Steel Sets For The Yucca Mountain Repository — Quarterly Technical Report No. 5, Dhanesh Chandra, Jaak J.K. Daemen

Publications (YM)

This report encompasses the work done for this third quarter, 2005, 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 have started 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 also performed (1) …

Effect Of Interface States On Spin-Dependent Tunneling In Fe/Mgo/Fe Tunnel Junctions, Kirill D. Belashchenko, Julian P. Velev, Evgeny Y. Tsymbal

Materials Research Science and Engineering Center: Faculty Publications

The electronic structure and spin-dependent tunneling in epitaxial Fe/MgO/Fe(001) tunnel junctions are studied using first-principles calculations. For small MgO barrier thickness the minority-spin resonant bands at the two interfaces make a significant contribution to the tunneling conductance for the antiparallel magnetization, whereas these bands are, in practice, mismatched by disorder and/or small applied bias for the parallel magnetization. This explains the experimentally observed decrease in tunneling magnetoresistance (TMR) for thin MgO barriers. We predict that a monolayer of Ag epitaxially deposited at the interface between Fe and MgO suppresses tunneling through the interface band and may thus be used to …

Structure Of Human Thymidylate Synthase Under Low-Salt Conditions, Leslie L. Lovelace, Wladek Minor, Lukasz Lebioda

Faculty Publications

Human thymidylate synthase, a target in cancer chemotherapy, was crystallized from PEG 3350 with 30 mM ammonium sulfate (AS) in the crystallization medium. The crystals are isomorphous with the high-salt crystals (~2.0 M AS) and the structure has been solved and refined (R = 22.6%, Rfree = 24.3%) at 1.8 Å resolution. The high- and low-AS-concentration structures are quite similar, with loop 181-197 is in the inactive conformation. Also, residues 95-106 and 129-135 (eukaryotic inserts region) show high mobility as assessed by poor electron density and high values of crystallographic temperature factors (residues 1-25 and 108-129 are disordered in both …

Modular Communication System, Stephen O. Bozzone, Bonnie Bachman, Ryan Nilsen

Economics Faculty Research & Creative Works

A modular communication system (10) can include an adaptable communication module (12) having a transceiver (13) coupled to a processor (14) and memory (20), and a first interface block (24) coupled to the processor, and a host device (30) having a power source (36), a user interface (34), and a second interface block (46). The host device can be among a plurality of host devices having different user interfaces and the processor is adaptable to control the different user interfaces when the first interface block recognizes the second interface block. The module can further include a DSP (16) and a …

Freeze-Form Extrusion Fabrication Of Ceramics, Tieshu Huang, Michael S. Mason, Greg Hilmas, Ming-Chuan Leu

Materials Science and Engineering Faculty Research & Creative Works

A novel, environmentally friendly solid freeform fabrication method called Freeze-form Extrusion Fabrication (FEF) has been developed for the fabrication of ceramic-based components. The method is based on deposition of ceramic pastes using water as the media. The ceramic solids loading can be 50 vol. % or higher and initial studies have focused on the use of aluminum oxide (Al₂O₃). The FEF system components and their interaction are examined, and the main process parameters affecting part geometry defined. 3-D shaped components have been fabricated by extrusion deposition of the ceramic paste in a layer-by-layer fashion. The feasibility …

Integral Channels In Metal Components And Fabrication Thereof, Rajiv S. Mishra

Materials Science and Engineering Faculty Research & Creative Works

An internal channel in a metal body for use in applications where internal fluid flow within a metal body is desired, as in a heat exchanger. The internal channel is formed in the metal body by frictionally stirring with a pin plunged into the metal body, and traversing the metal body with the pin.

Modeling, Fabrication, And Optimization Of Niobium Cavities Final Phase: Final Report, Robert A. Schill Jr., Mohamed Trabia, William Culbreth

Transmutation Sciences Materials (TRP)

This final report provides the activities and accomplishments of Modeling, Fabrication, and Optimization of Niobium Cavities – Final Phase. The fluid flow experiments for the etching of the superconducting cavity walls and baffle designs of phase II of the three phases has been completed leading to a MS thesis in December of 2003. Designing the experimental setup of secondary electron emission was well underway in early summer of 2003 when funding was made available for this portion of the study. By March 2004, many of the components of the experimental study reached UNLV with some assembly accomplished. The first secondary …

Domain-Wall Magnetoresistance Of Co Nanowires, Renat F. Sabiryanov, Ashok K. Solanki, John D. Burton, Sitaram Jaswal, Evgeny Y. Tsymbal

Materials Research Science and Engineering Center: Faculty Publications

Using density functional theory implemented within a tight-binding linear muffin-tin orbital method we perform calculations of electronic, magnetic, and transport properties of ferromagnetic free-standing fcc Co wires with diameters up to 1.5 nm. We show that finite-size effects play an important role in these nanowires resulting in oscillatory behavior of electronic charge and the magnetization as a function of the wire thickness, and a nonmonotonic behavior of spin-dependent quantized conductance. We calculate the magnetoresistance (MR) of a domain wall (DW) modeled by a spin-spiral region of finite width sandwiched between two semi-infinite Co wire leads. We find that the DW …

High Temperature Heat Exchanger Project: Quarterly Progress Report April 1, 2005 Through June 30, 2005, Anthony Hechanova

Publications (NSTD)

Quarterly Collaboration Meeting. General Atomics hosted a UNLVRF HTHX Project quarterly meeting on June 5 in San Diego, California. The purpose of the meeting was to promote collaboration and communication among the UNLV Research Foundation partners. Collaborators had the opportunity to discuss their research program plan and update their progress. The next meeting will be in September in Berkeley hosted by UC Berkeley.

HTHX Computational Design (UNLV). Work on optimizing the ceramic offset strip in compact HTHX design through parametric studies was performed and completed. A simple single channel model was used to perform parametric studies on dimensions and flow …

Use Of Positron Annihilation Spectroscopy For Stress-Strain Measurements: Quarterly Progress Report (March – May 2005), Ajit K. Roy

Transmutation Sciences Materials (TRP)

Accomplishments:

● Analyses of defects (dislocations) in martensitic Alloy EP-823, cold-reduced to different levels, have been performed by using transmission electron microscopy. The dislocation density has been related to the degree of cold-reduction and residual stress in terms of a line-shape parameter determined by the positron annihilation spectroscopy (PAS).

● Additional PAS measurements are ongoing on tensile, welded and cold-worked specimens of Alloys EP-823 and HT-9 at the Idaho Accelerator Center of ISU. Both Subhra and Silpa are involved in these measurements.

● Silpa is performing neutron diffraction (ND) measurements at the Atomic Energy of Canada Limited (AECL), Chalk River …

Sub-Surface Corrosion Research On Rock Bolt System, Perforated Ss Sheets And Steel Sets For The Yucca Mountain Repository — Quarterly Technical Report No. 4, Dhanesh Chandra, Jaak J.K. Daemen

Publications (YM)

This report encompasses the work done for this third quarter, 2005, 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 have started 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 also performed hydrogen …

Effect Of Silicon Content On The Corrosion Resistance And Radiation-Induced Embrittlement Of Materials For Advanced Heavy Liquid Metal Nuclear Systems: Quarterly Progress Report (February – April 2005), Ajit K. Roy

Transmutation Sciences Materials (TRP)

This proposal is intended to study the effect of Si content not only on the corrosion resistance but also on the radiation-induced embrittlement of martensitic stainless steels. The susceptibility of these alloys with different Si content to stress corrosion cracking, general corrosion and localized corrosion will be evaluated in the molten LBE and aqueous environments of different pH values using state-of-the-art testing techniques. Testing in the aqueous media is intended to develop baseline data for comparison purpose. Radiation-induced embrittlement of these alloys will initially be studied by irradiating the test specimens with bremmstrahlung gamma radiation from 20-40 MeV electron beams …

Giant Electroresistance In Ferroelectric Tunnel Junctions, Mikhail Ye Zhuravlev, Renat F. Sabirianov, Sitaram Jaswal, Evgeny Y. Tsymbal

Materials Research Science and Engineering Center: Faculty Publications

The interplay between the electron transport in metal-ferroelectric-metal junctions with ultrathin ferroelectric barriers and the polarization state of a barrier is investigated. Using a model which takes into account screening of polarization charges in metallic electrodes and direct quantum tunneling across a ferroelectric barrier, we calculate the change in the tunneling conductance associated with the polarization switching. We find the conductance change of a few orders of magnitude for metallic electrodes with significantly different screening lengths. This giant electroresistance effect is the consequence of a different potential profile seen by transport electrons for the two opposite polarization orientations.

Strain Induced Half-Metal To Semiconductor Transition In Gdn, Chun-Gang Duan, Renat F. Sabirianov, Jianjun Liu, Wai-Ning Mei, Peter A. Dowben, J. R. Hardy

Materials Research Science and Engineering Center: Faculty Publications

We investigate the electronic structure and magnetic properties of GdN as a function of unit cell volume. Based on the first-principles calculations of GdN, we observe that there is a transformation in the conduction properties associated with the volume increase: first from half-metallic to semimetallic, then ultimately to semiconducting. We show that applying stress can alter the carrier concentration as well as mobility of the holes and electrons in the majority spin channel. In addition, we found that the exchange parameters depend strongly on lattice constant, thus the Curie temperature of this system can be enhanced by applying stress or …

Passport To The Materials World: Materials Engineering Outreach Activities, Katherine C. Chen, Lisa Christensen, Amanda Runciman

Materials Engineering

No abstract provided.

Method And Sealant For Weld Joints, David C. Van Aken, John A. Baumann, Richard J. Lederich, Rajesh Talwar

Materials Science and Engineering Faculty Research & Creative Works

A sealant for a weld joint and an associated weld joint and method are provided. The sealant includes aluminum and germanium and is characterized by a melting temperature that is lower than the melting temperature of the structural member that is joined. The sealant, which is disposed between faying surfaces of the structural members, can fill the spaces between the structural members to prevent the entry of chemicals, moisture, debris, and other substances, thereby reducing the likelihood of corrosion of the joint or structural members at the interface. Further, the sealant can be diffusion bonded to the faying surfaces, for …

Development Of Project-Based Introductory To Materials Engineering Modules, Stacy Gleixner, Elliot Douglas, Olivia Graeve, Hilary Lackritz, Laura Demsetz, Amy Moll

Faculty Publications

This paper will discuss the progress of curriculum development under an NSF, CCLI-EMD sponsored work, “Development of Project-Based Introductory to Materials Engineering Modules” (DUE # #0341633). A multi-university team of faculty are developing six lecture and three laboratory modules for use in Introductory to Materials courses. This course is required by most engineering programs in the U.S., with an annual enrollment of 50,000 students. This freshman/ sophomore class is an ideal place to excite students about their engineering majors and expose them to engineering design experiences. PRIME Modules, Project Based Resources for Introduction to Materials Engineering, are being developed that …

Positive Spin Polarization In Co/Alo3 /Co Tunnel Junctions Driven By Oxygen Adsorption, Kirill D. Belashchenko, Evgeny Y. Tsymbal, Ivan I. Oleynik, Mark Van Schilfgaarde

Materials Research Science and Engineering Center: Faculty Publications

Using a first-principles Green's function technique, we study spin-dependent tunneling in two model realizations of (111) fcc Co/Al3/Co tunnel junctions assuming O-terminated crystalline epitaxy in the corundum structure. For the first model, which includes 3 O atoms at the interface, the tunneling current is polarized negatively, just as for the clean Co surface. The second model contains additional oxygen atoms inside large pores at each interface. Located at the three-fold hollow adsorption sites, these O atoms bind very strongly to Co. This bonding creates an interface band in the majority-spin channel which strongly enhances the tunneling current in this channel. …

Dissolution, Reactor, And Environmental Behavior Of Zro2-Mgo Inert Fuel Matrix: Quarterly Report, April 2005 To June 2005, Earl Wolfram, Thomas Hartmann, Kenneth Czerwinski

Fuels Campaign (TRP)

This project will examine inert matrix fuels containing ZrO₂ and MgO as the inert matrix, with the relative amount of MgO varied from 30% to 70% in ZrO₂. Reactor physics calculations will be used to examine suitable quantities of burnable poisons from the candidate elements Gd, Er, or Hf with reactor grade Pu providing the fissile component, with up to 10 % of ²³⁹Pu. Ceramics will be synthesized and characterized based on the reactor physics results. The solubility the fuel ceramics, in reactor conditions, reprocessing conditions, and repository conditions, will be investigated in a manner to …

Dynamic Matrix Composition In Engineered Cartilage With Stochastic Supplementation Of Growth Factors, Asit K. Saha, J. (Jagannath) Mazumdar, Sean S. Kohles

Mechanical and Materials Engineering Faculty Publications and Presentations

Dynamic extracellular matrix (ECM) synthesis is explored in a hypothesized engineered cartilage construct. Growth (α) and decay (β) rate parameters are developed from a previous engineered cartilage model. The presented mathematical model was constructed from the parameterized experimental data using a deterministic and stochastic examination of ECM synthesis based on a negative feedback control mechanism. A growth factor supplementation is incorporated in a probabilistic mathematical approach. The growth factor component modified an initial deterministic model through a Gaussian white noise fluctuation. As the primary constituents of ECM, the mathematical tool is intended to characterize the probable steady state distribution of …

Possible Side Reactions Due To Water In Emulsion Polymerization By Late Transition Metal Complexes Ii: Deactivation Of The Catalyst By A Wacker-Type Reaction, Roger L. Dekock, Iordan H. Hristov, Grant D. W. Anderson, Inigo Göttker-Schnetmann

University Faculty Publications and Creative Works

The transition metal catalyzed ethylene polymerization in water suspensions has been increasingly successful in the last couple of years. Water, however, adversely affects the polymerization process by deactivating the catalyst in a Wacker-type reaction. The cationic Pd(II)-diimine Brookhart catalyst 1 is studied here by a combination of quantum mechanics and molecular mechanics to determine the nature of the decomposition reaction. The study considers the decomposition process to take place in two stages. In the first stage, a coordinated olefin is attacked by a hydroxide group to ultimately produce a β-hydroxy-ethyl complex 2. The second step represents a decomposition to acetaldehyde …