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Articles 751 - 780 of 813

Full-Text Articles in Mechanical Engineering

A Scientific Foundation Of Collaborative Engineering, S. C.-Y. Lu, W. Elmaraghy, G. Schuh, R. Wilhelm Jan 2007

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

Department of Mechanical and Materials Engineering: Faculty Publications

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

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Single-Sided Crash Cushion System, John D. Reid, John R. Rohde, Dean L. Sicking Dec 2006

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

Department of Mechanical and Materials Engineering: Faculty Publications

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

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End Splice Assembly For Box-Beam Guardrail And Terminal Systemis, John D. Reid, John R. Rohde, Dean L. Sicking, King K. Mak Aug 2006

End Splice Assembly For Box-Beam Guardrail And Terminal Systemis, John D. Reid, John R. Rohde, Dean L. Sicking, King K. Mak

Department of Mechanical and Materials Engineering: Faculty Publications

An end splice assembly for a box-beam guardrail and terminal system having a first stage rail element and a second stage rail element. The assembly has two major connecting components. Upper and lower bent plate channels and upper and lower channel splice plates. The channels and plates have side walls which extend laterally to one another when the two rail elements are mated. The channels and plates are fastened together to provide moment strength to the splice within the system.

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Preparation Of High-Strength Nanometer Scale Twinned Coating And Foil, Xinghang Zhang, Amit Misra, Michael Nastasi, Richard G. Hoagland Jul 2006

Preparation Of High-Strength Nanometer Scale Twinned Coating And Foil, Xinghang Zhang, Amit Misra, Michael Nastasi, Richard G. Hoagland

Department of Mechanical and Materials Engineering: Faculty Publications

Very high strength single phase stainless steel coating has been prepared by magnetron sputtering onto a substrate. The coating has a unique microstructure of nanometer spaced twins that are parallel to each other and to the substrate surface. For cases where the coating and substrate do not bind strongly, the coating can be peeled off to provide foil.

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Statistical Interpretation Of Mohr-Coulomb Theory As Applied To Fracture In Brittle Materials Containing Cracks, Mudit J. Monsi Jul 2006

Statistical Interpretation Of Mohr-Coulomb Theory As Applied To Fracture In Brittle Materials Containing Cracks, Mudit J. Monsi

Mechanical & Aerospace Engineering Theses & Dissertations

Fracture in brittle materials containing pre-existing cracks was studied. The probability of of crack growth under both shear and tensile stresses was determined for an arbitrary distribution of crack sizes. Two different crack orientation distributions, random and uniform, as well as friction were also taken into account. The material's reliability was assumed to depend on the number of active cracks at a particular stress level, and this was expressed as an arbitrary 2-parameter Weibull distribution. Two new and efficient methods for calculating crack growth probabilities based on spherical triangles and spherical caps were developed. They utilized normalized stress coordinates and …

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Modeling And Representation Of Geometric Tolerances Information In Integrated Measurement Processes, Xiaoping Zhao, T. M. Kethara Pasupathy, Robert G. Wilhelm May 2006

Modeling And Representation Of Geometric Tolerances Information In Integrated Measurement Processes, Xiaoping Zhao, T. M. Kethara Pasupathy, Robert G. Wilhelm

Department of Mechanical and Materials Engineering: Faculty Publications

Modeling and representation of geometric tolerances information across an enterprise is viable due to the advances in Internet technologies and increasing integration requirements from industry. In Integrated Measurement Processes (IMP), geometric tolerances data model must support different models from several well-defined standards: including ASME Y14.5M-1994, STEP, DMIS, and others. In this paper, we propose a layered conformance level geometric tolerances representation model. This model uses the widely applied ASME Y14.5M-1994 as its foundation layer by abstracting most information from this standard. The additional geometric tolerances information defined by DMIS and STEP is incorporated into this model to form corresponding conformance …

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Flexible Tools For Specifying Design Variation, Trichy Pasupathy, Xiaoping Zhao, Robert Wilhelm Apr 2006

Flexible Tools For Specifying Design Variation, Trichy Pasupathy, Xiaoping Zhao, Robert Wilhelm

Department of Mechanical and Materials Engineering: Faculty Publications

This paper describes flexible tools for specifying design variations that are based on nonuniform profile tolerance definitions. These tools specify bounds of design performance that can be used for negotiation among engineers in a collaborative design process. These specification methods allow for the capture of many different design functions that are not easily described with current tool designs. In addition, these specification methods lend themselves to efficient verification methods. Profile tolerance definitions provide the most general variation controls for complex mechanical surfaces. Common design practices and engineering standards for profile tolerances exhibit many weaknesses and limitations. We present a rationale …

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Nanoparticle-Induced Negative Differential Resistance And Memory Effect In Polymer Bistable Light-Emitting Device, Ricky J. Tseng, Jianyong Ouyang, Chih-Wei Chu, Jinsong Huang, Yang Yang Jan 2006

Nanoparticle-Induced Negative Differential Resistance And Memory Effect In Polymer Bistable Light-Emitting Device, Ricky J. Tseng, Jianyong Ouyang, Chih-Wei Chu, Jinsong Huang, Yang Yang

Department of Mechanical and Materials Engineering: Faculty Publications

Recently, electrical bistability was demonstrated in polymer thin films incorporated with metal nanoparticles [J. Ouyang, C. W. Chu, C. R. Szmanda, L. P. Ma, and Y. Yang, Nat. Mater. 3, 918 (2004)]. In this letter, we show the evidence that electrons are the dominant charge carriers in these bistable devices. Direct integration of bistable polymer layer with a light-emitting polymer layer shows a unique light-emitting property modulated by the electrical bistability. A unique negative differential resistance induced by the charged gold nanoparticles is observed due to the charge trapping effect from the nanoparticles when interfaced with the light-emitting layer.

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In Vivo Laparoscopic Robotics, Mark E. Rentschler, Stephen R. Platt, Jason Dumpert, Shane M. Farritor, Dmitry Oleynikov Jan 2006

In Vivo Laparoscopic Robotics, Mark E. Rentschler, Stephen R. Platt, Jason Dumpert, Shane M. Farritor, Dmitry Oleynikov

Department of Mechanical and Materials Engineering: Faculty Publications

Robotic laparoscopic surgery is evolving to include in vivo robotic assistants. The impetus for the development of this technology is to provide surgeons with additional viewpoints and unconstrained manipulators that improve safety and reduce patient trauma. A family of these robots have been developed to provide vision and task assistance. Fixed-base and mobile robots have been designed and tested in animal models with much success. A cholecystectomy, prostatectomy, and nephrectomy have all been performed with the assistance of these robots. These early successful tests show how in vivo laparoscopic robotics may be part of the next advancement in surgical technology.

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The Role Of Electrospinning In The Emerging Field Of Nanomedicine, S. Y. Chew, Y. Wen, Yuris A. Dzenis, K. W. Leong Jan 2006

The Role Of Electrospinning In The Emerging Field Of Nanomedicine, S. Y. Chew, Y. Wen, Yuris A. Dzenis, K. W. Leong

Department of Mechanical and Materials Engineering: Faculty Publications

The fact that in vivo the extracellular matrix or substratum with which cells interact often includes topography at the nanoscale underscores the importance of investigating cell-substrate interactions and performing cell culture at the submicron scale. An important and exciting direction of research in nanomedicine would be to gain an understanding and exploit the cellular response to nanostructures. Electrospinning is a simple and versatile technique that can produce a macroporous scaffold comprising randomly oriented or aligned nanofibers. It can also accommodate the incorporation of drug delivery function into the fibrous scaffold. Endowed with both topographical and biochemical signals such electrospun nanofibrous …

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Efficient Inverted Polymer Solar Cells, G. Li, C.-W. Chu, V. Shrotriya, Jinsong Huang, Y. Yang Jan 2006

Efficient Inverted Polymer Solar Cells, G. Li, C.-W. Chu, V. Shrotriya, Jinsong Huang, Y. Yang

Department of Mechanical and Materials Engineering: Faculty Publications

We investigate the effect of interfacial buffer layers—vanadium oxide (V2O5) and cesium carbonate (Cs2CO3)—on the performance of polymer solar cells based on regioregular poly-(3-hexylthiophene) and [6,6]-phenyl C60 butyric acid methyl ester blend. The polarity of solar cells can be controlled by the relative positions of these two interfacial layers. Efficient inverted polymer solar cells were fabricated with the structure of indium tin oxide (ITO)/Cs2CO3/polymer blend/vanadium oxide (V2O5)/aluminum (Al). Short-circuit current of 8.42 mA/cm2, open-circuit voltage of 0.56 V, and power conversion efficiency of …

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Improving The Power Efficiency Of White Light-Emitting Diode By Doping Electron Transport Material, Jinsong Huang, Wei-Jen Hou, Juo-Hao Li, Gang Li, Yang Yang Jan 2006

Improving The Power Efficiency Of White Light-Emitting Diode By Doping Electron Transport Material, Jinsong Huang, Wei-Jen Hou, Juo-Hao Li, Gang Li, Yang Yang

Department of Mechanical and Materials Engineering: Faculty Publications

Highly efficient white light emission was realized via the partial energy transfer from blue host polyfluorene (PF) to orange light emission dopant rubrene. A more balanced charge transport was achieved by adding an electron transport material, 2-(4-biphenylyl)-5-(4-tertbutylphenyl)-1,3,4-oxadiazole (PBD), into the PF-rubrene system to enhance the electron transportation. Efficiency improvement by as much as a factor of 2 has been observed through the addition of PBD. These devices can easily reach high luminance at low driving voltages, thus achieving high power efficiency at high luminance (14.8, 13.5, and 12.0 lm/W at the luminances of 1000, 2000, and 4000 cd/m2, …

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Piezoelectromagnetic Waves In A Ceramic Plate Between Two Ceramic Half-Spaces, S. N. Jiang, Q. Jiang, X. F. Li, S. H. Guo, H. G. Zhou, J. S. Chang Jan 2006

Piezoelectromagnetic Waves In A Ceramic Plate Between Two Ceramic Half-Spaces, S. N. Jiang, Q. Jiang, X. F. Li, S. H. Guo, H. G. Zhou, J. S. Chang

Department of Mechanical and Materials Engineering: Faculty Publications

We analyze the propagation of piezoelectromagnetic waves guided by a plate of polarized ceramics between two ceramic half-spaces. An exact dispersion relation is obtained, which reduces to a few known elastic, electromagnetic, and quasistatic piezoelectric wave solutions in the literature as special cases. Numerical solutions to the equation that determines the dispersion relation show the existence of guided waves. The results are useful for acoustic wave and microwave devices.

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Cracking Of Martensitic Alloy Ep-823 Under Controlled Potential, Ajit K. Roy, M. K. Hossain Jan 2006

Cracking Of Martensitic Alloy Ep-823 Under Controlled Potential, Ajit K. Roy, M. K. Hossain

Mechanical Engineering Faculty Research

The susceptibility of martensitic Alloy EP-823 to stress corrosion cracking was evaluated with and without an applied cathodic potential using the slow-strain-rate (SSR) testing technique. The magnitude of the applied potential was based on the corrosion potential determined by cyclic polarization. The cracking susceptibility in an acidic environment at different temperatures was expressed in terms of the true failure stress (ơf), time to failure (TTF), and ductility parameters, including percent elongation (%El) and percent reduction in area (%RA). The data indicate that the magnitudes of ơr, TTF, %El, and %RA were reduced due to cathodic charging. …

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Evolutionary Algorithm For The Placement Of Fluid Power Valves On A Valve Stand, Trichy M. Kethara Pasupathy, Ravi Teja Seethamraju, Robert G. Wilhelm Aug 2005

Evolutionary Algorithm For The Placement Of Fluid Power Valves On A Valve Stand, Trichy M. Kethara Pasupathy, Ravi Teja Seethamraju, Robert G. Wilhelm

Department of Mechanical and Materials Engineering: Faculty Publications

The choice of placement of fluid power valves on a valve stand and routing by pipes has an impact on operational costs. Choosing the right placement that provides optimum routing configuration or determining the optimum routing for a chosen placement are both computationally hard problems. An evolutionary algorithm (EA), to minimize operational costs while optimizing placement and routing of valves, is developed here. The best practices in the industry are abstracted and implemented in the EA. In this paper, the algorithm and its performance for examples with varying complexities are presented. Our results meet or exceed experienced designers’ solutions.

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Tensile Properties Of Martensitic Stainless Steels At Elevated Temperatures, Ajit K. Roy, Srinivasarao R. Kukatla, Bhagath Yarlagadda, V. N. Potluri, Martin Lewis, Brendan O'Toole Apr 2005

Tensile Properties Of Martensitic Stainless Steels At Elevated Temperatures, Ajit K. Roy, Srinivasarao R. Kukatla, Bhagath Yarlagadda, V. N. Potluri, Martin Lewis, Brendan O'Toole

Mechanical Engineering Faculty Research

Tensile properties of quenched and tempered martensitic alloys EP-823, HT-9, and 422 were evaluated at temperatures ranging from ambient to 600 °C as a function of three different tempering times. The results indicated that the yield strength, ultimate tensile strength, and the failure strength were gradually reduced with increasing temperature. The ductility parameters were enhanced at elevated temperatures due to increased plastic flow. However, the tempering time did not significantly influence these properties. The evaluation of the fracture surfaces by scanning electron microscopy revealed reduced cracking and dimpled microstructures, indicating enhanced ductility at higher testing temperatures.

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Residual Stress Characterization In Structural Materials By Destructive And Nondestructive Techniques, Ajit K. Roy, Anand Venkatesh, Vikram Marthandam, Satish Dronavalli, Douglas P. Wells, Ronald Rogge Apr 2005

Residual Stress Characterization In Structural Materials By Destructive And Nondestructive Techniques, Ajit K. Roy, Anand Venkatesh, Vikram Marthandam, Satish Dronavalli, Douglas P. Wells, Ronald Rogge

Mechanical Engineering Faculty Research

Transmutation of nuclear waste is currently being considered to transform long-lived isotopes to species with relatively short half-lives and reduced radioactivity through capture and decay of minor actinides and fission products. This process is intended for geologic disposal of spent nuclear fuels for shorter durations in the proposed Yucca Mountain repository. The molten lead-bismuth-eutectic will be used as a target and coolant during transmutation, which will be contained in a subsystem vessel made from materials such as austenitic (304L) and martensitic (EP-823 and HT-9) stainless steels. The structural materials used in this vessel will be subjected to welding operations and …

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Electronic Commerce Negotiation In A Supply Chain Via Constraint Evaluation, R. Wilhelm, B. Chu, R. Sun Jan 2005

Electronic Commerce Negotiation In A Supply Chain Via Constraint Evaluation, R. Wilhelm, B. Chu, R. Sun

Department of Mechanical and Materials Engineering: Faculty Publications

Negotiation is of critical importance in e-commerce applications where the supply chain is dynamic and reconfiguring. In this research supply chain negotiation problems are addressed as constraint-satisfaction problems. In general each negotiation is handled in the largest scope possible to avoid the suboptimality that can result from many local solutions. This global approach, however, must be balanced with time constraints that apply in e-commerce supply chain execution. In this paper, we describe a new approach for e-commerce supply chain negotiation via constraint evaluation. As well, results from prototype software, distributed across the internet, are discussed. Beyond the general formulation, we …

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Influence Of Composition And Heat-Treatment On The Charge Transport Properties Of Poly(3-Hexylthiophene) And [6,6]-Phenyl C61-Butyric Acid Methyl Ester Blends, Jinsong Huang, Gang Li, Yang Yang Jan 2005

Influence Of Composition And Heat-Treatment On The Charge Transport Properties Of Poly(3-Hexylthiophene) And [6,6]-Phenyl C61-Butyric Acid Methyl Ester Blends, Jinsong Huang, Gang Li, Yang Yang

Department of Mechanical and Materials Engineering: Faculty Publications

Poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl C61-butyric acid methyl ester (PCBM) blends have been demonstrated to form highly efficient polymer photovoltaic devices. In this letter, the time-of-flight technique is used to investigate the influence of composition and heat treatment on charge transport properties of P3HT and PCBM blends. The transport of electrons and holes both display a transition from dispersive to nondispersive and return to dispersive again as the percentage of PCBM increases. A balanced mobility of both electron and hole is obtained at a composition of 1:1 weight ratio, and it is nearly independent of the electrical field in …

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Stress Corrosion Cracking Resistance Of Martensitic Stainless Steels For Transmutation Applications, Phani P. Gudipati Dec 2004

Stress Corrosion Cracking Resistance Of Martensitic Stainless Steels For Transmutation Applications, Phani P. Gudipati

UNLV Theses, Dissertations, Professional Papers, and Capstones

The susceptibility of Alloy EP-823 to stress corrosion cracking has been evaluated using smooth and notched cylindrical specimens in neutral and acidic solutions at ambient and elevated temperatures using constant load and slow strain rate testing (SSR) techniques. C-ring and U-bend specimens have also been tested in the acidic solution. The effect of hydrogen on the cracking susceptibility has been evaluated under controlled cathodic potential. While no failures were observed with smooth specimens at constant load, the notched specimens showed failure. The SSR test results indicate that the true failure stress (o'f), time to failure and ductility parameters …

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Stress Corrosion Cracking And Hydrogen Embrittlement Of Martensitic Alloy Ep-823, Mohammad K. Hossain Dec 2004

Stress Corrosion Cracking And Hydrogen Embrittlement Of Martensitic Alloy Ep-823, Mohammad K. Hossain

UNLV Theses, Dissertations, Professional Papers, and Capstones

This investigation is focused on the evaluation of stress corrosion cracking (SCC), localized corrosion, and hydrogen embrittlement (HE) susceptibility of martensitic Alloy EP-823 in neutral and acidic solutions at ambient and elevated temperatures. While no failures were observed in smooth specimens in the neutral solution, failures were noticed in the 90°C acidic solution at constant-load (CL) leading to a threshold stress (O'th) of 102 ksi. The presence of a notch reduced the O'th value to 91 ksi in a similar environment. The ductility (%El and %RA), time-to-failure (TTF), and true failure stress (O'r) were gradually …

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Cfd Analysis Of 3-D Thermalhydraulics Flow Effects On Wall Concentration Gradient Profiles For Lbe Loop Fittings, Narain Armbya Dec 2004

Cfd Analysis Of 3-D Thermalhydraulics Flow Effects On Wall Concentration Gradient Profiles For Lbe Loop Fittings, Narain Armbya

UNLV Theses, Dissertations, Professional Papers, and Capstones

The objective of the thesis is to study the effects of thermalhydraulics flows on the wall concentration gradient profiles in LBE loop fittings. To that end detailed models of the fittings have been constructed to study these effects. These fittings include sudden expansion, sudden contraction, t-joint and elbow. The typical flow rates chosen for these simulations are typical of design criteria chosen for the loop with Reynolds numbers expected around 200,000 and the usual axial temperature profiles which are being characterized in the DELTA loop at LANL. STAR-CD is the simulation package used to make these predictions, which include detailed …

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Science For Stewardship: Multidisciplinary Research On Uss Arizona, Matthew A. Russell, Larry E. Murphy, Donald L. Johnson, Timothy J. Foecke, Pamela J. Morris, Raphy Mitchell Oct 2004

Science For Stewardship: Multidisciplinary Research On Uss Arizona, Matthew A. Russell, Larry E. Murphy, Donald L. Johnson, Timothy J. Foecke, Pamela J. Morris, Raphy Mitchell

Department of Mechanical and Materials Engineering: Faculty Publications

The National Park Service’s Submerged Resources Center and USS Arizona Memorial are conducting and coordinating research directed at understanding the nature and rate of natural processes affecting the deterioration of the USS Arizona in Pearl Harbor, Hawaii. The USS Arizona Preservation Project is designed to be multi-year, interdisciplinary and cumulative, with each element contributing to developing an overall management strategy designed to minimize environmental hazard from fuel oil release and provide the basic research required to make informed management decisions for long-term preservation. The primary project focus is toward acquiring requisite data for understanding the complex corrosion and deterioration processes …

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Embrittlement And Localized Corrosion In Alloy Ht-9, Sudheer Sama Aug 2004

Embrittlement And Localized Corrosion In Alloy Ht-9, Sudheer Sama

UNLV Theses, Dissertations, Professional Papers, and Capstones

This investigation is focused on the evaluation of stress corrosion cracking (SCC), hydrogen embrittlement (HE) and localized corrosion susceptibility of Alloy HT -9 in neutral and acidic solutions at 30, 60 and 90°C. Constant-load and slow-strain-rate (SSR) testing techniques were used to evaluate the SCC and HE behavior of this alloy by using smooth and notched tensile specimens. Hydrogen effect on the cracking behavior was evaluated by applying cathodic (negative) potential to the test specimens. Localized corrosion susceptibility was evaluated by cyclic potentiodynamic polarization technique. The results of constant load SCC testing showed a threshold stress at 80% of the …

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Environment-Induced Degradations In A Target Structural Material For Transmutation Applications, Ramprashad Prabhakaran Aug 2004

Environment-Induced Degradations In A Target Structural Material For Transmutation Applications, Ramprashad Prabhakaran

UNLV Theses, Dissertations, Professional Papers, and Capstones

This investigation is focused on the evaluation of stress corrosion cracking (SCC) and localized corrosion behavior of Type 422 stainless steel in aqueous environments at ambient and elevated temperature. The results of constant load SCC testing using smooth specimens showed no failure in the neutral solution but a threshold stress of 97 ksi was observed in the 90°C acidic environment. SCC testing by the slow-strain-rate test method indicate that the time-to-failure, true failure stress and ductility parameters were gradually reduced with increasing temperature, showing more pronounced effect in the acidic solution. The application of a controlled cathodic potential showed further …

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Bar Clamp Having Ergonomic Handle, M. Susan Hallbeck, Myung-Chul Jung Jan 2004

Bar Clamp Having Ergonomic Handle, M. Susan Hallbeck, Myung-Chul Jung

Department of Mechanical and Materials Engineering: Faculty Publications

The present invention generally relates to a handle assembly for a hand operable bar clamp having a fixed jaw, a movable jaw and a drive for translating the movable jaw towards the fixed jaw. The assembly includes a handgrip and a trigger handle. The handgrip having an elongated rear portion has a generally rounded surface and being contoured to complement the natural transverse curve pf a human palm. The trigger handle is pivotal with respect to the handgrip. The trigger handle included an elongated front portion having a rounded front surface and being contoured to complement the natural palmer curve …

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Trailer Mounted Bursting Energy Absorption System, John D. Reid, John R. Rohde, Dean L. Sicking Dec 2003

Trailer Mounted Bursting Energy Absorption System, John D. Reid, John R. Rohde, Dean L. Sicking

Department of Mechanical and Materials Engineering: Faculty Publications

A portable crash attenuation System having a trailer frame and an energy absorption mechanism attached thereto. The absorption mechanism has a first Stage pivotably connected to a Second Stage and the Second Stage is pivotably connected to the frame. By pivoting the Stages about hinges the attenuation System may be folded from an extended, deployed position or mode to a shortened transit mode for easy relocation of the entire attenuation System.

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Chemical Kinetics And Thermal Hydraulics Of Lead Bismuth Flow Loops, Kanthi Kiran Dasika Dec 2003

Chemical Kinetics And Thermal Hydraulics Of Lead Bismuth Flow Loops, Kanthi Kiran Dasika

UNLV Theses, Dissertations, Professional Papers, and Capstones

The objective of the thesis is to study the effect of chemical kinetics and thermal hydraulics of Lead Bismuth Eutectic (LBE) flow in the Materials Test Loop (MTL). The Materials Test Loop, also known as the Delta Loop, was built in Los Alamos National Laboratories (LANL) to obtain the experimental data for corrosion estimation and analysis. It is a well-known fact that corrosion plays an important role in the design of nuclear thermal hydraulic systems. Since the MTL is a multi-section closed system that differs in diameter from one part to another, an intensive study on the overall and regional …

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Study Of Geometric Effects On Local Corrosion Rates For Lbe Loop, Chao Wu Jul 2003

Study Of Geometric Effects On Local Corrosion Rates For Lbe Loop, Chao Wu

UNLV Theses, Dissertations, Professional Papers, and Capstones

Corrosion is an extremely important issue in nuclear cooling system applications. Many scientific and engineering efforts have been contributed to the research of finding an ideal material, which has resistance to corrosive Lead Bismuth Eutectic (LBE). A Delta Loop was designed and constructed in Los Alamos National Lab (LANL) to obtain the experimental data. This loop is a multi-section closed system that differs in diameter from one part to another. As a result, an intensive study on the geometry effect is hence necessary and valuable. In this thesis, this problem was simulated by commercial software STAR-CD. Results provide a good …

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Optically Transparent, Scratch-Resistant, Diamond-Like Carbon Coatings, Xiao-Ming He, Deok-Hyung Lee, Michael A. Nastasi, Kevin C. Walter, Michel G. Tuszewski Jun 2003

Optically Transparent, Scratch-Resistant, Diamond-Like Carbon Coatings, Xiao-Ming He, Deok-Hyung Lee, Michael A. Nastasi, Kevin C. Walter, Michel G. Tuszewski

Department of Mechanical and Materials Engineering: Faculty Publications

A plasma-based method for the deposition of diamond-like carbon (DLC) coatings is described. The process uses a radio-frequency inductively coupled discharge to generate a plasma at relatively low gas pressures. The deposition process is environmentally friendly and scaleble to large areas, and components that have geometrically complicated surfaces can be processed. The method has been used to deposit abherent 100-400 nm thick DLC coatings on metals, glass, and polymers. These coatings are between three and four times harder than steel and are therefore scratch resistant, and transparent to visible light. Boron and silicon doping of the DLC coatings have produced …

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