Engineering Commons^™

Fluoride Release From Model Glass Ionomer Cements, A. Guida, R. G. Hill, Mark R. Towler, S. Eramo

Chemical and Biochemical Engineering Faculty Research & Creative Works

Glass ionomer cements (GICs) are an important class of biomedical material used extensively for color matched mercury free, dental restorations. GICs can release clinically beneficial amounts of fluoride and have acceptable handling properties which make them suitable as dental restoratives. The fluoride release of model GICs produced from specially synthesized fluoro-alumino-silicate glasses was studied. Nine glasses of varying fluoride content based on 4.5SiO₂-3Al₂O₃-1.5P₂O₅-(5-Z)CaO-ZCaF₂ were synthesized, and cement disks were prepared from them. The glass transition temperature reduced with increasing fluorine content of the glass. Fluoride ion release was measured …

A Preliminary Study Of An Aluminum-Free Glass Polyalkenoate Cement, Mark R. Towler, C. M. Crowley, D. Murphy, A. M.C. O'Callaghan

Chemical and Biochemical Engineering Faculty Research & Creative Works

No abstract provided.

Raman Scattering And Lattice Defects In Nanocrystalline Ceo2 Thin Films, Igor Kosacki, Toshio Suzuki, Harlan U. Anderson, Philippe Colomban

Materials Science and Engineering Faculty Research & Creative Works

The results of Raman scattering studies of nanocrystalline CeO₂ thin films are presented. The spectra have been described using the spatial correlation model from which the correlation length has been determined as a function of grain size. A direct comparison between the concentration of defects related to correlation length and CeO₂ non-stoichiometry has been achieved. The relationship between the lattice disorder and the form of the Raman spectra in nanocrystalline CeO₂ is discussed. © 2002 Elsevier Science B.V. All rights reserved.

Eye Pattern Evaluation In High-Speed Digital Systems Analysis By Using Mtl Modeling, Giulio Antonini, James L. Drewniak, Antonio Orlandi, Vittorio Ricchiuti

Electrical and Computer Engineering Faculty Research & Creative Works

A method for simulating the eye pattern of high-speed digital signals propagated on printed circuit boards using multiconductor transmission-line modeling is proposed in this paper. The approach takes into account the frequency-dependent properties of the dielectric materials of the board and of the conductors. The validation is performed by comparing the modeling with measurements taken from the literature, and directly performed on test boards specially design for this study.

Strength And Modulus Degradation Of Carbon Fiber-Reinforced Polymer Laminates From Fiber Misalignment, Xinbao Yang, Antonio Nanni, Stephen B. Haug, Chung Leung Sun

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Fiber-reinforced polymer (FRP) laminates are being used as external reinforcement for strengthening concrete members. The performance of unidirectional FRP laminates is highly dependent on fiber orientation with respect to applied load direction. In the case of fabrication by manual layup, it is possible to have fiber plies installed with improper orientation. In this project, the degradation of strength and modulus of carbon FRP laminates from fiber misalignment was investigated experimentally using tensile coupons. The specimens consisted of one and two plies of unidirectional carbon FRP impregnated with a two-component epoxy. The misalignment angles varied from 0 to 40° for the …

Performance Of Cold-Formed Steel-Framed Shear Walls: Alternative Configurations, Kelly A. Morgan, Mark A. Sorhouet, Reynaud Serrette

American Iron and Steel Institute (AISI) Specifications, Standards, Manuals and Research Reports (1946 - present)

This report presents the results of twenty shear wall tests that were conducted to evaluate the performance of wall configurations not currently (2002) permitted in the building codes. Ten (10) walls were evaluated under reversed cyclic loading and the other ten (10) under monotonic loading. Brief descriptions of the test program and results are presented in the following paragraphs. The reversed cyclic load tests comprised 4 ft. x 8 ft. 54- and 68-mil framed walls with 7/16-in. OSB rated sheathing on one or both sides of the wall and 33-mil framed walls with 27-mil sheet steel. The sheet steel wall …

Engineering Management At Umr -- Alumni Voices, Stephen A. Raper

Engineering Management and Systems Engineering Faculty Research & Creative Works

The Department of Engineering Management at the University of Missouri-Rolla is among the oldest of its kind in the United States, and has over 2000 Bachelors level alumni graduates. The Department will undergo ABET accreditation under the new assessment based criteria in the fall of 2002. The new criteria specify that engineering programs should seek to continuously improve their degree offerings through an ongoing assessment process that includes constituent input. Our own department has specified undergraduate alumni as one of the prime or key constituents that will be queried for input into our own processes. For the first time in …

Principles Of Biology In Environmental Engineering: Molecular Biology-Based Identification Of Microorganisms, Daniel B. Oerther

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The various aspects of a course on use of technology from molecular biology to screen microorganism in environmental samples and to monitor microbial biocatalysts in reactors, is discussed. The objective of the course is to teach students to adapt techniques from molecular biology to address important issues in environmental engineering. In case of methanogens, design considerations in environmental engineering include stabilization of sewage sludge through anaerobic digestion and wastewater treatment. The hands-on format encourages students to develop scientific questions, learn appropriate methodology, conduct careful experimentation, and draw conclusions worthy of presentation.

Adaptive Predictive Congestion Control Of High-Speed Atm Networks, Sarangapani Jagannathan, Jayasree Talluri

Electrical and Computer Engineering Faculty Research & Creative Works

This paper proposes an auto regressive moving average (ARMAX)-based adaptive control methodology to prevent congestion in high-speed asynchronous transfer mode (ATM) networks. Adaptive controller is developed to control traffic where sources adjust their transmission rates in response to the feedback information from the network switches. Specifically, the buffer dynamics at a given switch is modeled as a nonlinear discrete-time system and an ARMAX controller is designed so as to predict the explicit values of the transmission rates of the sources so as to prevent congestion. Tuning methods are provided for the unknown coefficients of the ARMAX model to estimate the …

Incorporating Web-Based Homework Problems In Engineering Dynamics, Ralph E. Flori, David B. Oglesby, Timothy A. Philpot, Nancy E. Hubing, Richard H. Hall, Vikas Yellamraju

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

We are involved in a project funded by the Department of Education (FIPSE) which focuses on developing interactive software to improve the teaching and learning of engineering statics, dynamics, and mechanics of materials. This paper presents an overview of this project, discusses its objectives, and focuses on one particular aspect of the project.the use of web-based homework problems as assessment tools to evaluate student learning. The overall project includes creating, for all three engineering mechanics courses, the following web-based learning tools: (a) Animated theory modules, using Macromedia.s Flash development software, which display basic theory and example problems in an engaging, …

Formal Engineering Of Residential Buildings, Joseph E. Minor

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The performance of residential buildings during hurricanes is as important as the performance of other buildings. Buildings where people live and where they are likely to be when a hurricane strike must survive. If this premise is accepted, it follows that residential buildings should be afforded a degree of engineering attention that is commensurate with that given to industrial and commercial buildings. Building code authorities have not been blind to this need. In new procedures adopted for hurricane zones in the United States, common sizes and geometric shapes of timber and masonry residential buildings are formally engineered, and associated construction …

Magnetic And Mössbauer Studies On Oxygen Deficient Perovskite, La₀.₆Sr₀.₄Feo3-Δ, Jinbo Yang, William B. Yelon, William Joseph James, X.-D. Zhou, Yixiang Xie, Harlan U. Anderson, Zili Chu

Physics Faculty Research & Creative Works

Samples of La_0.6Sr_0.4Fe_3-δ with varying oxygen vacancy contents were prepared by heating them in different gas flows. Magnetization measurement showed that samples with low oxygen vacancies have a magnetic ordering temperature in the range of 300-325 K while those with 9%-12% oxygen vacancies have a magnetic ordering temperature of 800 K and higher. Mössbauer spectra at 300 K exhibit paramagnetic or weak magnetic characteristics for the N₂, O₂, and air-quenched samples, whereas an average hyperfine field of 52 T is found for the CO/CO₂ reduced samples. The heat treatment in …

Structure And Magnetic Properties Of The Mnbi Low Temperature Phase, Jinbo Yang, William B. Yelon, William Joseph James, Qingsheng Cai, Samit Roy, Naushad Ali

Physics Faculty Research & Creative Works

High purity MnBi low temperature phase has been prepared and analyzed using magnetic measurements and neutron diffraction. The low-temperature phase of the MnBi alloy has a coercivity μ_0iH_c of 2.0 T at 400 K, and exhibits a positive temperature coefficient from 0 to at least 400 K. The neutron data refinement indicated that the Mn atom changes its spin direction from c axis above room temperature to nearly perpendicular to the c axis at 50 K. A canted magnetic structure has been observed below 200 K. The anisotropy field increases with increasing temperature which gives rise to …

Standard For Cold-Formed Steel Framing -- General Provisions, American Iron And Steel Institute

American Iron and Steel Institute (AISI) Specifications, Standards, Manuals and Research Reports (1946 - present)

The material contained herein has been developed by the American Iron and Steel Institute Committee on Framing Standards. The Committee has made a diligent effort to present accurate, reliable, and useful information on cold-formed steel framing design and installation. The Committee acknowledges and is grateful for the contributions of the numerous researchers, engineers, and others who have contributed to the body of knowledge on the subject. Specific references are included in the General Provisions document. With anticipated improvements in understanding of the behavior of cold-formed steel framing and the continuing development of new technology, this material may eventually become dated. …

Standard For Cold-Formed Steel - General Provisions, American Iron And Steel Institute

American Iron and Steel Institute (AISI) Specifications, Standards, Manuals and Research Reports (1946 - present)

The material contained herein has been developed by the American Iron and Steel Institute Committee on Framing Standards. The Committee has made a diligent effort to present accurate, reliable, and useful information on cold-formed steel framing design and installation. The Committee acknowledges and is grateful for the contributions of the numerous researchers, engineers, and others who have contributed to the body of knowledge on the subject. Specific references are included in the General Provisions document.

With anticipated improvements in understanding of the behavior of cold-formed steel framing and the continuing development of new technology, this material may eventually become dated. …

Standard For Cold-Formed Steel Framing - Header Design, American Iron And Steel Institute

American Iron and Steel Institute (AISI) Specifications, Standards, Manuals and Research Reports (1946 - present)

The material contained herein has been developed by the American Iron and Steel Institute Committee on Framing Standards. The Committee has made a diligent effort to present accurate, reliable, and useful information on cold-formed steel framing design and installation. The Committee acknowledges and is grateful for the contributions of the numerous researchers, engineers, and others who have contributed to the body of knowledge on the subject. Specific references are included in the Commentary.

With anticipated improvements in understanding of the behavior of cold-formed steel framing and the continuing development of new technology, this material may eventually become dated. It is …

Standard For Cold-Formed Steel Framing Truss Design, American Iron And Steel Institute

American Iron and Steel Institute (AISI) Specifications, Standards, Manuals and Research Reports (1946 - present)

The material contained herein has been developed by the American Iron and Steel Institute Committee on Framing Standards. The Committee has made a diligent effort to present accurate, reliable, and useful information on cold-formed steel framing design and installation. The Committee acknowledges and is grateful for the contributions of the numerous researchers, engineers, and others who have contributed to the body of knowledge on the subject. Specific references are included in the Truss Standard document.

With anticipated improvements in understanding of the behavior of cold-formed steel framing and the continuing development of new technology, this material may eventually become dated. …

Overhang Effects On End-One-Flange Web Crippling Capacity Of Cold-Formed Steel Members, Michael W. Holesapple, Roger A. Laboube

American Iron and Steel Institute (AISI) Specifications, Standards, Manuals and Research Reports (1946 - present)

No abstract provided.

Testing Of Steel L-Headers On Wood Walls, Nahb Research Center

CCFSS Library (1939 - present)

No abstract provided.

Room-Temperature Homogeneous Nucleation Synthesis And Thermal Stability Of Nanometer Single Crystal Ceo₂, X.-D. Zhou, Wayne Huebner, Harlan U. Anderson

Materials Science and Engineering Faculty Research & Creative Works

Nanometer (about 4~5nm) CeO₂ single crystals were first synthesized by room-temperature homogeneous nucleation; the size was determined by electron microscopy and specific surfaced area of the particles. Modeling revealed that the surface energy of as-synthesized nanometer single crystals was in the range of 2.8-3.7J/m². Crystal growth mechanisms change over the temperature regimes, from boundary diffusion over low-temperature regime (E_α=0.16eV) to bulk diffusion (E_α=0.50eV) over high-temperature region.

Estimating The Noise Mitigation Effect Of Local Decoupling In Printed Circuit Boards, Jun Fan, Wei Cui, James L. Drewniak, Thomas Van Doren, James L. Knighten

Electrical and Computer Engineering Faculty Research & Creative Works

Local decoupling, i.e., placing decoupling capacitors sufficiently close to device power/ground pins in order to decrease the impedance of power bus at frequencies higher than the series resonant frequency, has been studied using a modeling approach, a hybrid lumped/distributed circuit model established and an expression to quantify the benefits of power bus noise mitigation due to local decoupling developed. In this work, a test board with a local decoupling capacitor was studied and the noise mitigation effect due to the capacitor placed adjacent to an input test port was measured. Closed-form expressions for self and mutual inductances of vias are …

Electron–Phonon Interactions In Htsc Cuprates, Takeshi Egami, J-H Chung, Rj Mcqueeney, Mohana Yethiraj, Herbert A. Mook, C. Frost, Y. Petrov, Fatih Dogan, Yasuhiro Inamura, Masatoshi Arai, Setsuuko Tajima, Yasuo Endoh

Materials Science and Engineering Faculty Research & Creative Works

Phonons have been generally considered to be irrelevant to the high-temperature superconductivity in the cuprates. However, such a bias is usually based upon the assumption of conventional electron–phonon coupling, while in the cuprates the coupling can be rather unconventional because of strong electron correlation. We present the results of our recent measurements of phonon dispersion in YBa₂Cu₃O_6+x by inelastic neutron scattering. These suggest certain phonon modes interact strongly with electrons and are closely involved in the superconductivity phenomenon with possible contribution to pairing.

Evaluation Of Lead Anode Reactions In Acid Sulfate Electrolytes: Ii. Manganese Reactions, Pu Yu, Thomas J. O'Keefe

Materials Science and Engineering Faculty Research & Creative Works

Lead alloys containing calcium-tin, silver, or similar combinations are the primary insoluble anodes used for copper and zinc electrowinning. One potential concern with these anodes is the detrimental effect on cathode purity from incorporation of lead corrosion products. Other factors which are important to process economics are the reaction potential and overpotential required for oxygen evolution. In addition to the inherent overpotential, impurities in the electrolyte can have a significant polarization impact, such as the films that may form when manganese is present. In order to gain a better understanding of the fundamental behavior of various concentrations of manganese ions …

Extracting Cad Models For Quantifying Noise Coupling Between Vias In Pcb Layouts, Shaofeng Luan, Jun Fan, W. Liu, Fengchao Xiao, James L. Knighten, Norman W. Smith, Ray Alexander, Jim Nadolny, Yoshio Kami, James L. Drewniak

Electrical and Computer Engineering Faculty Research & Creative Works

A method to extract a lumped element prototype SPICE model is used to study noise coupling between non-parallel traces on a PCB. The parameters in this model are extracted using a PEEC-like approach, a Circuit Extraction approach based on a Mixed-Potential Integral Equation formulation (CEMPIE). Without large numbers of unknowns, the SPICE model saves computation time. Also, it is easy to incorporate into system SPICE net list to acquire the system simulation result considering the coupling between traces on the printed circuit board (PCB). A representative case is studied, and the comparison of measurements, CEMPIE simulation, and SPICE modeling are …

Optical Limiting In Srbi₂Ta₂O₉ And Pbzrxti₁₋ₓo₃ Thin Films, Pingxiong Yang, Jianfeng Xu, Robert W. Schwartz, David L. Carroll, John Ballato

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Optical limiting effects in SrBi2Ta2O9 (SBT) and PbZrxTi1-xO3 (PZT) ferroelectric thin films have been observed with nanosecond laser pulses at 1.064 µm. Limiting thresholds were found to be 5.84 J/cm2 for SBT and between 4.53 and 5.93 J/cm2 for PZT, depending on composition, whereas saturation thresholds for the films were about 2.92 J/cm2 and between 2.27 J/cm2 to 2.97 J/cm2, respectively. Damage thresholds around 10.0 J/cm2 and between 10.37 J/cm2 to 10.54 J/cm2, respectively for SBT and PZT, were also determined. A possible mechanism for the observed limiting, nonlinear optical scattering from the ferroelectric domains, is discussed. These results elucidate …

Fdtd Modeling Of Skin Effect, Chen Wang, James L. Drewniak, Min Li, Jun Fan, James L. Knighten, Norman W. Smith, Ray Alexander, Jingyu Huang

Electrical and Computer Engineering Faculty Research & Creative Works

The data rates and clock speeds of current highspeed signals are increasing rapidly, consequently, not only the lossy nature of FR-4 but also the lossy nature of good conductors, such as copper, need to be taken into account in high-speed signal designs. In order to well predict the loss caused by both dielectric loss and skin effect loss, a suitable simulation tool is needed. A surface impedance boundary condition (SIBC) algorithm was implemented in FDTD modeling herein to accommodate the skin effect loss due to finite conductivity of good conductors. Good agreement between the FDTD result and the measurements as …

Cancellation Of Mri Motion Artifact In Image Plane, Eung-Kyeu Kim, Nohpill Park, Minsu Choi, S. Tamura

Electrical and Computer Engineering Faculty Research & Creative Works

In this study, a new algorithm for canceling a MRI artifact due to the translational motion in image plane is described. Unlike the conventional iterative phase retrieval algorithm, in which there is no guarantee for the convergence, a direct method for estimating the motion is presented. In previous approaches, the motions in the x(read out) direction and the y(phase encoding) direction were estimated simultaneously. However, the feature of x and y directional motions are different from each other. By analyzing their features, each x and y directional motion is canceled by the different algorithms in two steps. First, it is …

Bending Strength Of Hybrid Cold-Formed Steel Beams, Chi Ling Pan, Wei Wen Yu

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

For the purpose of determining the load-carrying capacity of cold-formed steel structural members, the effective width approach has been used. Since most studies were limited only to the structural members, which were assembled from the same material in a given section, this investigation was concentrated on a study of structural strength and behavior of hybrid cold-formed steel beams subjected dynamic loads. An investigation was also conducted to study the validity of effective design width formulas for the design of these specimens. The materials used in this study were 25 AK and 50 SK sheet steels. A total of 72 spot-welded …

Biodegradable Glass Compositions And Methods For Radiation Therapy, D. E. Day, James E. White

Materials Science and Engineering Faculty Research & Creative Works

A nonradioactive glass in particulate form adapted for radiation therapy in a mammal comprise a biodegradable rare earth-lithium borate glass material of a specified composition which, upon being subjected to an effective amount of neutron irradiation, will produce a beta or gamma emitting radioisotope, the radioisotope being distributed throughout the glass material, the glass upon being introduced into a body fluid for radiation therapy being adapted to react therewith causing the radioisotope to form an insoluble compound on the surface of the glass material which is retained in the glass material and thereby prevented from escaping from the treatment site. …

Spectral Analysis Of Transition Metal-Doped Mgo “Matched Emitters” For Thermophotovoltaic Energy Conversion, Lucian G. Ferguson, Fatih Dogan

Materials Science and Engineering Faculty Research & Creative Works

A new, thermally excited Co/Ni-doped MgO ceramic emitter for TPV energy conversion is described in this work and termed the “matched emitter” because its emissive power spectrum is very efficiently matched with the portion of the electromagnetic spectrum that can be converted directly into electrical energy by infrared responding GaSb photovoltaic cells. Ligand Field Theory calculations are used to estimate the crystal field splitting energies at high temperatures for Co and Ni-doped MgO matched emitters. Experimental measurements of the high temperature (1300–1400◦C) emissive power spectrums for Co and Ni-doped MgO emitters are compared with predictions obtained from ligand field calculations …