| Micromachined Fabry-Perot Interferometer for Motion Detection |
10 SEP 2002 |
4 pages |
| Authors:
Richard L. Waters; Monti E. Aklufi; SPACE AND NAVAL WARFARE SYSTEMS CENTER SAN DIEGO CA
|
 | The monolithic integration of a Fabry-Perot interferometer and a (100) silicon photodiode is reported for use as a highly sensitive transduction method in the detection of minute displacements of a proof mass attached to a spring. The combination results in a compact device with active transistor-like amplification and minimal parasitic elements, The transducer is fabricated using standard surface micromachining techniques. The finesse of the optical cavity, incident optical power, and ... |
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| Probabilistic Modeling and Simulation of Metal Fatigue Life Prediction |
SEP 2002 |
134 pages |
| Authors:
Thomas V. Heffern; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| As fiscal constraints demand maximum utilization, engineers must develop more rigorous methods to predict the life limits of aircraft components Current Navy policy requires that aircraft and aircraft parts be retired before they reach 100% FLE An investigation has been initiated that would attempt to quantify the probability of failure if aircraft parts were extended in service life beyond 100% FLE The work of this thesis was to investigate the ... |
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| Experimental Studies of Welding Effects on Damping for Undersea Warfare Applications |
SEP 2002 |
72 pages |
| Authors:
Agustin E. Carey; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| Damping in structures has historically been of great importance in nearly all branches of engineering endeavors, and it also happens to be one of the most difficult parameters to predict. The purpose of this research is to study the effects that welding has on damping. Measurements and comparisons of the damping ratios of two welded stiffened plates, two flat plates and one machined stiffened plate are undertaken. The frequency response ... |
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| Joining of Gamma Titanium Aluminides |
SEP 2002 |
114 pages |
| Authors:
William A. Baeslack III; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH MATERIALS AND MANUFACTURING DIRECTORATE
|
| This report summarizes, interprets and comparatively discusses the results of research and development performed on the joining of gamma titanium aluminides during the past two decades. Although organized and presented by joining process, many of the observations made and relationships developed, particularly those regarding the weldability and welding metallurgy of gamma titanium aluminides, are broadly applicable. Generally, the basic welding processes and techniques utilized in the fusion and solid -state ... |
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| Characterization of Steels Using a Revised Kinematic Hardening Model Incorporating Bauschinger Effect |
AUG 2002 |
22 pages |
| Authors:
Anthony P. Parker; Edward Troiano; John H. Underwood; Charles Mossey; ARMY ARMAMENT RESEARCH DEVELOPMENT AND ENGINEERING CENTER WATERVLIET NY BENET LABS
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| A new variant of the nonlinear kinematic hardening model is proposed that accommodates both nonlinear and linear strain hardening during initial tensile loading and reduced elastic modulus during initial load reversal. It also incorporates the Bauschinger effect, as a function of prior tensile plastic strain, during the nonlinear compressive loading phase. The model is shown to fit experimental data from a total of five candidate gun steels. The numerical fits ... |
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| Evaluation of Residual Stresses and Their Influence on Distortion in the Decoiling and Welding Processes |
AUG 2002 |
34 pages |
| Authors:
Wojciech Z. Misiolek; Pawel Kazanowski; LEHIGH UNIV BETHLEHEM PA INST FOR METAL FORMING
|
| An analysis of de-coiling process is provided. The expression for equilibrium of internal stresses within de-coiled plate during welding was established. First simulations of the de-coiling process have been prepared using Finite Element Modeling technique. Experimental verification of numerical results has been performed. The experimental results are in very good agreement with the numerical results. More insight into the changes of the sample material during deformation was achieved by careful ... |
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| Modeling of Metal Laser Cutting Processes in Supersonic Jet in Inert Gas |
JUL 2002 |
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| Authors:
O. B. Kovalev; A. M. Orishich; V. M. Fomin; V. B. Shulyatev; RUSSIAN ACADEMY OF SCIENCES NOVOSIBIRSK INST OF THEORETICAL AND APPLIED MECHANICS
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 | Up-to-date CO2 lasers are widely used in laser treatment of materials (drilling, welting, cutting). Technical achievements of laser methods both in Russia and abroad are limited and have been applied only for some types of ferrous metals until now (iron, steel, stainless steel, electrical steel). A number of works, cannot describe satisfactory the processes of gas-laser metal cutting, and this fact implies consideration of a great number of complex and ... |
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| Experimental Study on the Effect of Misfit and Mismatch of Ship Plating Welds |
JUN 2002 |
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| Authors:
Robert E. Bebermeyer; MASSACHUSETTS INST OF TECH CAMBRIDGE DEPT OF MECHANICAL ENGINEERING
|
| Misfits and mismatches in the welding of ship hull plating may affect survivability after explosions, accidents, or other extreme external forces. Experiments, Slip Line Theory (SLT), and Finite Element Analysis (FEA) help to explain the necking, deformation, and mechanisms of fracture of misfit welded plating. The effect of misfits or offsets on both overmatched and evenmatched welds under tension are studied. The tension creates a moment about the offset weld ... |
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| Post-CMOS Micromachining of Surface and Bulk Structures |
06 May 2002 |
241 pages |
| Authors:
Xu Zhu; CARNEGIE-MELLON UNIV PITTSBURGH PA DEPT OF ELECTRICAL AND COMPUTER ENGINEERING
|
| This thesis describes fabrication of the micro-electro-mechanical system (MEMS) through post Complementary-Metal-Oxide-Semiconductor (CMOS) micromachining. It focuses on device fabrication instead of device designs. The reactive-ion-etch (RIE) and deep-reactive-ion-etch (DRIE) are key technologies in this process flow. Surface micromachining of the thin-film dielectric material and bulk micromachining of the Si substrate are discussed in detail. Fundamentals of the RIE and DRIE dry etch, the methodology to characterize these process techniques and ... |
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| Welding of Electron Beam Single Melt Ti-6Al-4V Plate |
MAY 2002 |
38 pages |
| Authors:
William S. De Rosset; Matthew Burkins; Brijmohan Roopchand; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| Single melt titanium alloy is being considered for use as armor in ground combat vehicles due to its lower cost relative to aerospace-grade material. This report examines welding issues associated with fabricating titanium alloy plate. In particular, the quality of welded single melt material was investigated as well as the possibility of out-of-position welding of standard titanium alloy. The initial results indicate that single melt material can be welded using ... |
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| Effects of Shot-Peening on High Cycle Fretting Fatigue Behavior of Ti- 6Al-4V |
26 MAR 2002 |
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| Authors:
Halil I. Yuksel; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING AND MANAGEMENT
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| Effects of Shot-peening on High Cycle Fretting Fatigue behavior of Ti-6Al-4V were investigated. Experiments were performed with 6.35 mm thick specimens which provided S/N curves. After the tests, it was observed that the specimens failed near the trailing edge of contact. Scanning Electron Microscopy showed that cracks initiated on the contact surface for 6.35 mm, and at the depth of specimen ranging from 200 to 300 microns for 3.81 mm ... |
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| High-Power COIL and YAG Laser Welding |
24 JAN 2002 |
9 pages |
| Authors:
Fumio Wani; Tokuhiro Nakabayashi; Akiyoshi Hayakawa; Sachio Suzuki; Kozo Yasuda; KAWASAKI HEAVY INDUSTRIES LTD KOBE (JAPAN)
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| We have constructed a laser welding system, which enabled high-power laser welding by combining three laser beams of 1 micrometer wavelength. Its wavelength enables optical silica fibers transmission and the flexible system. The heart of this system consists of a 4 kW and a 6 kW Nd:YAG lasers and a 10 kW Chemical Oxygen-Iodine Laser (COIL). The average power of the combined beam is up to over 20 kW. The ... |
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| Analysis of Three UH-60 Blackhawk Servolink Components P/N 70400-08110- 061 |
JAN 2002 |
53 pages |
| Authors:
Marc Pepi; Victor Champagne; Daniel Snoha; Scott Grendahl; James Catalano; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| The Processing and Properties Branch of the U.S. Army Research Laboratory's (ARL) Weapons and Materials Research Directorate examined the shot- peened surfaces of three UH-60 Blackhawk utility helicopter servolinks. It was purported that the surfaces of the components were damaged from a prior manufacturing operation. ARL performed visual and stereoscopic examination of the surface, measured the depth of some scratches, and quantified the residual stresses at the surface through x-ray ... |
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| NCEMT 2002 Annual Report. Ensuring Navy Transformation Through Affordable Metalworking Technologies |
Jan-2002 |
17 pages |
| Authors:
CONCURRENT TECHNOLOGIES CORP JOHNSTOWN PA NMC INFORMATION SERVICES
|
| In this time of historic change, we of the NCEMT are responding to the challenge to rapidly transform U.S. Navy and defense capabilities. We ore adopting new paradigms and reaching beyond old expectations to assist civil and military partners who ore in need of our services now more than ever before. At the NCEMT, the commitment to transformation is deep, fundamental and unwavering. |
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| Vacuum Infusion of Low-Cost Aerospce Composites |
2002 |
|
| Authors:
Maarten Labordus; R. C. Verhoef; INSTITUTE OF INDUSTRIAL TECHNOLOGY TNODELFT (NETHERLANDS)
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| This report results from a contract tasking TNO Industrie as follows: A mold system will be designed in which the hydrostatic pressure can be measured in the resin during the vacuum infusion process. Pressure transducers will be mounted in the surface of a flat aluminum plate and data will be digitally recorded. Simple compression tests on dry and impregnated laminate will provide data to relate the pressure gradient (out of ... |
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| Thermal Conductivity Evolution During Initial Stage Sintering |
2002 |
10 pages |
| Authors:
Constance E. Schlaefer; Randall M. German; PENNSYLVANIA STATE UNIV UNIVERSITY PARK
|
| The effective thermal conductivity of injection-molded material is useful as a means of monitoring initial stage sintering. Data obtained via laser flash analysis are inputs for a model relating thermal conductivity to strength. Multiple measurements can be made during a single sintering cycle, detailing the growth of interparticle bonds and onset of handling strength. |
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| Thermal Quenching of Photoluminescence from Er-Doped GaN Thin Films |
2002 |
6 pages |
| Authors:
J. T. Seo; U. Hoemmerich; D. C. Lee; J. Heikenfeld; A. J. Steckl; J. M. Zavada; HAMPTON UNIV VA DEPT OF PHYSICS
|
| The green (537 and 558 nm) and near infrared (1.54 micrometers) photoluminescence (PL) spectra of Er-doped GaN thin films have been investigated as a function of temperature, excitation wavelength, and pump intensity. Thermal quenching measurements showed that the integrated green Er(exp 3+) PL intensity (4S(sub 3/2)/2H(sub11/2)->4I(sub 15/2) remained nearly constant up to 150 K, but decreased at higher temperatures due to a less efficient Er(exp 3+) excitation. The integrated infrared ... |
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| Mikrosystemtechnische Realisierung von Induktivitaeten (Microsystem- Technical Realization of Inductances) |
OCT 2001 |
|
| Authors:
Florian Wiest; UNIVERSITAET DER BUNDESWEHR MUENCHEN NEUBIBERG (GERMANY) FAKULTAET FUER ELEKTROTECHNIK
|
| The dissertation discusses a completely new concept for the realization of specific inductance construction forms, with which, in parallel construction, one might work on a multitude of coils integrated into processing usage. Firstly, the author sets out his principles for production and characterization; secondly, he describes the usage process in detail, so as to provide examples for his empirical research. The next and largest chapter focuses on the deformation of ... |
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| Patterning Lipid Bilayers on Microfabricated Metal Electrodes |
17 SEP 2001 |
14 pages |
| Authors:
Reid N. Orth; Ismail Hafez; Jun Kmeoka; Manfred Lindau; Harold G. Craighead; CORNELL UNIV ITHACA NY SCHOOL OF APPLIED AND ENGINEERING PHYSICS
|
| Lipid molecules were immobilized on surface of photolithographically patterned chromium and titanium. Large unilamellar lipid vesicles were found to bind on the native oxide surface of patterned support metals. Metal evaporation and resist liftoff techniques were used to pattern metal an a hydrophobic polymer surface. Lipids bound on solid substrates provide a biological interface for current measuring electrodes to detect bound cell or biomaterial. This patterning technique provides means to ... |
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| Growth and Characterization of High Frequency Materials |
15 SEP 2001 |
19 pages |
| Authors:
R. E. Camley; Z. Celinski; COLORADO UNIV AT COLORADO SPRINGS DEPT OF PHYSICS
|
| This instrumentation award had following objectives: (1) Obtain a sputtering deposition system (2) Upgrade a UHV system to a Molecular Beam Epitaxy system (3) Build new FMR (ferromagnetic resonance) systems (4) Upgrade BLS (Brillouin Light Scattering) system. All of these objectives have been accomplished. We purchase a sputtering system equipped with 5 guns and E-beam system. We upgraded deposition system to a single chamber MBE system. We built four FMR ... |
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| High Strength Steel Weldment Reliability |
AUG 2001 |
46 pages |
| Authors:
D. L. Olson; COLORADO SCHOOL OF MINES GOLDEN CENTERFOR WELDING JOINING AND COATINGS RESEARCH
|
| The development of methods to control the diffusible hydrogen content during high strength steel welding was performed. The perfection of the use of irreversible weld metal hydrogen traps was demonstrated. Efforts have effectively alleviated the available diffusible hydrogen, and thus the susceptibility of hydrogen assisted cracking, by the use of ferro yttrium additions to the welding consumable. The range of welding parameter for the most effective use of yttrium as ... |
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| Advanced Computational Techniques for the Design of Deformation Processes |
Jul 2001 |
7 pages |
| Authors:
Nicholas Zabaras; CORNELL UNIV ITHACA NY MATERIALS PROCESS DESIGN AND CONTROL LABORATORY (MPDC)
|
| The objective of this work is to develop a continuum sensitivity finite element analysis for the robust design of multi-stage metal forming processes in aircraft manufacturing. The computational forming design simulator being developed is applied to industrial forming design and provides the means to select the sequence of deformation processes, design the dies and preforms for each process stage as well as the process conditions such that a product is ... |
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| Bolt-Load Retention Behavior of a Die Cast Magnesium-Rare Earth Alloy |
25 JUN 2001 |
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| Authors:
Ian P. Moreno; MICHIGAN UNIV ANN ARBOR
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| The need for improved understanding of new magnesium alloys for the automotive industry continues to grow as the application for these lightweight alloys expands to more demanding environments, particularly in drivetrain components. Their use at elevated temperatures, such as in transmission cases, presents a challenge because magnesium alloys generally have lower creep resistance than aluminum alloys currently employed for such applications. In this study, a new die cast magnesium alloy, ... |
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| Advances in Hydrogen Management for High Strength Steel |
07 JUN 2001 |
18 pages |
| Authors:
Yeong-Do Park; Chad Lensing; Iman Maroef; David L. Olson; Zamir Gavra; COLORADO SCHOOL OF MINES GOLDEN CENTERFOR WELDING JOINING AND COATINGS RESEARCH
|
| Diffusible hydrogen content in high strength low alloy steels welding can be better managed with modifications to the low hydrogen welding consumables. The welding consumable alloy content needs to allow the weld metal to transform from austenite to ferrite/martensite at slightly higher temperature than the base metal does. This practice will allow for the best dispersal of hydrogen from the weld deposit and minimizing the tendency of localizing the hydrogen ... |
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| Ship Hull Plating Weld Misalignment Effects When Subjected to Tension |
JUN 2001 |
|
| Authors:
M. C. Weaver; DEPARTMENT OF THE NAVY WASHINGTON DC
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| Precision fabrication of ships is advancing. Welding is ubiquitous in ship construction and military standards have specified tolerances for joining plates in naval combatants. Precision manufacturing will allow the production of ships with smaller hull plate misalignments. A benefit from this could be improved ship survivability when subjected to underwater explosions. Slip Line Fracture Mechanics interacting with Finite Element Analysis (FEA) gives insight into the deformation, necking and fracture mechanisms ... |
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| Materials for High Temperature Applications |
JUN 2001 |
8 pages |
| Authors:
Kameleshwar Upsadhya; RAYTHEON INFORMATION TECHNOLOGY AND SCIENTIFIC CO EDWARDS AFB CA
|
| Investigation of the processing of a variety of high temperature materials was accomplished. Nanocrystalline silicon nitride powders were synthesized and hot isostatic pressed to produce material at 97% theoretical density after sintering. |
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| Development of Lightweight Fume Extraction Welding Guns |
21 MAY 2001 |
46 pages |
| Authors:
David Yapp; John Lawmon; Harvey Castner; EDISON WELDING INST COLUMBUS OH
|
| This report describes a project conducted for the NSRP SP-7 Welding Panel to develop a lightweight fume extraction welding gun for shipyard use. Shipbuilders are interested in fume extraction welding guns to improve worker comfort meet workplace safety requirements as well as environmental regulations. Current fume extraction welding guns have limited flexibility and are bulky compared to conventional guns Shipbuilders desire improved fume extraction guns to make them practical for ... |
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| Biomimicry-Based Strategy Towards the Development of a Structure- Function Map of the Glutamate Receptor Pore |
01 MAY 2001 |
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| Authors:
Mauricio Montal; CALIFORNIA UNIV SAN DIEGO LA JOLLA OFFICE OF CONTRACT AND GRANT ADMINISTRATION
|
| The main goal of this program was to establish a low resolution map for the pore-forming structure of the N-methyl-D-aspartate (NMDA) receptor, a major excitatory neurotransmitter receptor thought to be crucial for synaptic plasticity and neurotoxicity. Open channel blocker libraries were used as specific probes to explore accessibility of pore lining residues and, accordingly, infer the intricacies of the channel structure. The functional assay to identify channel blockers from synthetic ... |
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| Material Choices for Good Load Carriage Design |
MAY 2001 |
4 pages |
| Authors:
Gareth Davies; DEFENCE CLOTHING AND TEXTILES AGENCY ESSEX (UNITED KINGDOM)
|
| The paper discusses the selection of fabrics, webbing, tapes, sewing threads and the issues that surround their choice in the military scenario. How infrared signature is achieved on synthetic materials, so that service personnel are hidden from night sights, is explained. A weldable material has been identified in the UK offering the opportunity to produce waterproof rucksacks. The choice of interface materials to the body is discussed and the new ... |
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| Ejection-Seat-Quick-Release-Fitting Quantitative Fractography and Estimation of the Local Toughness using the Topography of the Fracture Surface |
05 APR 2001 |
7 pages |
| Authors:
K. Wolf; BUNDESWEHR RESEARCH INST FOR MATERIALS EXPLOSIVES FUELS AND LUBRICANTS ERDING(GERMANY)
|
| A Quick-Release-Fitting of an Ejection Seat broke and investigations were made to estimate the fracture mechanism on the basis of fracture surface characteristics. Fractographic based investigations normally use qualitative characteristics to purify the cause of the failure. Generally the determination of the fracture location and its origin, the kind of fracture and special features on the fracture surface are enough to describe the cause of the fracture. The aim of ... |
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| Mechanical Alloying Effects in Ball-Milled Tungsten-Copper (W-Cu) Composites |
APR 2001 |
62 pages |
| Authors:
Laszlo J. Keoskes; Matthew D. Trexler; Bradley R. Klotz; Kyu C. Cho; Robert J. Dowding; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| Fine-grained, high-density (97%+ of theoretical density TD), 80 tungsten-20 copper weight-percent (80W-20Cu 58W-42Cu atomic-percent) composites have been prepared using nonconventional alloying techniques. The W and Cu precursor powders were combined by high-energy ball milling in air. A second set of W+Cu mixtures was prepared in hexane to reduce contamination of the powders. The mechanically alloyed W+Cu powder mixtures were then coldpressed into green compacts and sintered at 1,250 deg. C. ... |
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| Studies of Transport Phenomena and Their Effect on Weld Quality in Laser Beam Welding |
31 MAR 2001 |
25 pages |
| Authors:
Hai-Lung Tsai; MISSOURI UNIV-ROLLA DEPT OF MECHANICAL AND AEROSPACE ENGINEERING
|
| The objective of this project was to study complicated transport phenomena (laser-material interaction, heat transfer, and molten metal fluid dynamics) and their effect on weld quality in laser beam welding. The study investigated the formation of keyholes, keyhole dynamics, and possible weld defects caused by keyhole instability. A mathematical model based on continuum formulation (for handling metal flow during alloy melting/solidification) and volume-of-fluid (for handling free surfaces) was successfully developed ... |
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| Quench Press Hardening with Low Copper Plating. Management and Operation of the DoD Instrumented Factory for Gears |
28 MAR 2001 |
114 pages |
| Authors:
IIT RESEARCH INST CHICAGO IL
|
| Copper plating is used as a carbon stop-off during the carburization and austenitization operations associated with the manufacture of precision gears. The "Low Copper" project's goals were to optimize the thickness of copper needed during carburization, and to eliminate the need to re-plate copper prior to austenitizing, via atmosphere control in a rotary furnace. Traditionally, plating that is 0.001 to 0.003 inch thick is used as a carbon stop-off. Experimentation ... |
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| NCEMT 2001 Annual Report. Ensuring Navy Readiness Through Affordable Metalworking Technologies |
Jan-2001 |
17 pages |
| Authors:
CONCURRENT TECHNOLOGIES CORP JOHNSTOWN PA
|
| The state of the NCEMT? Ready. Capable. Agile. Escalating the drive to discover more, reach higher and top past achievements. The NCEMT, established by the Navy Manufacturing Technology (MANTECH) Program in 1988, is working on a variety of projects to ensure the availability of proven, affordable technology capable of meeting military-unique demands. Scientists, engineers and other experts at the NCEMT are partnering with industry and government leaders to identify key ... |
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| Computational Modeling of Remelting Processes for Ingot Casting of High- Performance Alloys |
20 DEC 2000 |
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| Authors:
Kanchan M. Kelkar; Suhas V. Patankar; INNOVATIVE RESEARCH INC PLYMOUTH MN
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| Report developed under SBIR contract for topic AF00-168 describes the research performed towards the development of a comprehensive, efficient, and well-validated model for the ESR, VAR, EB and related remelting processes used for the production of ingots of superalloys and titanium alloys. The computational model incorporates many novel features in the treatment of the underlying electromagnetic, flow, and heat transfer phenomena and their computational solution. Thus, a unified framework for ... |
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| The National Shipbuilding Research Program. Emission Factors for Flux Core Rod Used in Gas Shielded Processes |
18 DEC 2000 |
57 pages |
| Authors:
NATIONAL STEEL AND SHIPBUILDING CO SAN DIEGO CA
|
| The shipbuilding and repair industry uses a wide variety of welding rods and wires in combination with various welding processes. These processes include, but are not limited to gas metal arc welding (GMAW), flux core arc welding (FCAW), shielded metal arc welding (SMAW), and submerged arc welding (SAW). There are presently some emission factors for welding operations that have been developed by the United States Environmental Protection Agency (USEPA) and ... |
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| Accessories for Enhancement of the Semi-Automatic Welding Processes |
12 DEC 2000 |
62 pages |
| Authors:
Douglas M. Wheeler; James M. Sawhill; NEWPORT NEWS SHIPBUILDING AND DRY DOCK CO VA
|
| The project's objective is to identify specific areas of the semi-automatic welding operation that is performed with the major semi-automatic processes, which would be more productive if a suitable mechanical or electrical accessory was available. Ideas were solicited and concepts proposed for accessories that would suit the identified applications when performing GMAW, FCAW, and GTAW processes. Interested manufacturers would work to develop and evaluate prototypes suitable for production shipbuilding environments. ... |
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| 2000 Gordon Research Conference on Electrodeposition |
31 OCT 2000 |
15 pages |
| Authors:
John Stickney; GORDON RESEARCH CONFERENCES INC KINGSTON RI
|
| The Gordon Research Conference (GRC) on Electrodeposition was held at Colby-Sawyer College, New London, NH, August 13-18, 2000. The conference was well attended with 106 participants. The attendees represented the spectrum of endeavor in this field coming from academia, industry, and government laboratories, both US and foreign scientists, senior researchers, young investigators, and students. In designing the formal speakers program, emphasis was placed on current unpublished research and discussion of ... |
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| Evaluation of PPT-2 Flux-Cored Titanium Weldment |
OCT 2000 |
23 pages |
| Authors:
Michael E. Wells; NAVAL SURFACE WARFARE CENTER CARDEROCK DIV BETHESDA MD
|
| A titanium weldment fabricated in 1/2-inch thick commercially pure plate with the PPT-2 flux-cored wire was obtained from The Paton Institute for evaluation. The results of nondestructive inspection showed that the flux cored wire and welding procedures used to produce the weldment resulted in a sound weld with no indications of cracking or other internal defects. Chemical analysis showed acceptable carbon, hydrogen, iron and oxygen ... |
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| The Effect of Cold Work on the Thermal Stability of Residual Compression in Surface Enhanced IN718 |
OCT 2000 |
10 pages |
| Authors:
Paul S. Prevey; LAMBDA RESEARCH CINCINNATI OH
|
| Surface enhancement, the creation of a layer of residual compression at the surface of a component, is widely used to improve the fatigue life in the automotive and aerospace industries. The compressive layer delays fatigue crack initiation and retards small crack propagation. The benefits of surface enhancement are lost if the compressive layer relaxes at the operating temperature of the component. Surface enhancement methods producing minimal cold work are shown ... |
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| Effect of Water Depth on the Underwater Wet Welding of Ferritic Steels Using Austenitic Ni-Based Alloy Electrodes |
SEP 2000 |
52 pages |
| Authors:
Brian J. Sheakley; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| Underwater welding using shielded metal arc welding (SMAW) on US naval Vessels is very attractive because of the ability to effect repairs without costly dry dock expenses. In the past the primary problems with underwater wet weldments on steels utilizing SMAW with ferritic electrodes, were underbead cracking in the heat affected zone (HAZ), slag inclusions, oxide inclusions, and porosity. To avoid underbead cracking three weld samples ... |
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| Continuous Dynamic Recrystallization During Friction Stir Welding of High Strength Aluminum Alloys |
SEP 2000 |
|
| Authors:
K. V. Jata; S. L. Semiatin; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH MATERIALS AND MANUFACTURING DIRECTORATE
|
| Friction stir welding (FSW) is a solid state joining process 1,2,3 that uses a rapidly-rotating, non-consumable high strength tool-steel pin that extends from a cylindrical shoulder (Figure 1). The workpieces to be joined are firmly clamped to a worktable; the rotating pin is forced with a pre-determined load into them and moved along the desired bond line. Frictional heating is produced from the rubbing of the rotating shoulder with the ... |
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| The Effect of Shot Peening Coverage on Residual Stress, Cold Work and Fatigue in a Ni-Cr-Mo Low Alloy Steel |
SEP 2000 |
7 pages |
| Authors:
P. S. Prevey; J. T. Cammett; LAMBDA RESEARCH CINCINNATI OH
|
| The underlying motivation for this work was to test the conventional wisdom that 100% coverage by shot peening is required to achieve full benefit in terms of compressive residual stress magnitude and depth as well as fatigue strength. Fatigue performance of many shot peened alloys is widely reported to increase with coverage up to 100%, by many investigators and even in shot peening manuals.(1) The fatigue strength of some alloys ... |
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| Copper and Cobalt Nanoclusters Embedded in Hydrogenated Amorphous Carbon: An X-Ray Absorption Study |
23 JUN 2000 |
4 pages |
| Authors:
A. V. Kolobov; H. Oyanagi; H. Akinaga; T. K. Zvonaryova; V. I. Ivanov-Omskii; RUSSIAN ACADEMY OF SCIENCES SAINT PETERSBURG IOFFE PHYSICAL-TECHNICAL INST
|
| This paper reports the results of X-ray absorption study (EXAFS anci XANES) of the dependence of the structure of clusters on the concentration of the metal and on annealing. |
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| A Comparison of Sputtering Models for Plasma-Surface Interactions |
18 JUN 2000 |
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| Authors:
D. B. VanGilder; D. E. Kirtley; J. M. Fife; M. R. Gibbons; AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIRECTORATE WEST
|
| The interaction of electric propulsion plumes with spacecraft surfaces is studied in order to predict possible spacecraft contamination. For example, ions in the plume may cause surface sputtering and this sputtered material may be deposited on other surfaces. Several models exist for the sputtering of surface material by ion bombardment based on various experimental data. These models depend on the ion species and materials from the data. In order to ... |
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| Palladium-Boron Alloys and Methods for Making and Using Such Alloys |
19 MAY 2000 |
16 pages |
| Authors:
Miles; DEPARTMENT OF THE NAVY WASHINGTON DC
|
| A palladium-boron composition and methods of making and using same are provided. In one aspect, the invention comprises an alloy comprising palladium and boron the boron being in solid solution in the palladium and the alloy having a two-phase structure, wherein each phase of the two-phase structure has the same crystal structure has the other phase and has a different set of lattice parameters from the other phase such that ... |
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| Carbon Equivalent (Pcm) Limits for Thick Carbon and Low Alloy Steels |
04 APR 2000 |
81 pages |
| Authors:
Jack H. Devletian; OREGON GRADUATE INST BEAVERTON
|
| Experimentally determined preheating/interpass temperatures necessary to prevent hydrogen-assisted cracking of restrained butt welds were established and compared to the best algorithms available to predict such cracking. Weldability tests on large-size plates of ABS & MIL-S-22698 Grades B D and DH-36 as well as ASTM A612 steels were conducted at Electric Boat Corporation using three different plate thicknesses three welding procedures and two levels of diffusible hydrogen. The plate thicknesses were ... |
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| Auto Feed Stud Gun for Insulation Pins |
16 FEB 2000 |
32 pages |
| Authors:
William C. Easterday; NAVAL SURFACE WARFARE CENTER CARDEROCK DIV BETHESDA MD
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| Develop a commercially viable lightweight stud welding gun with auxiliary apparatus suitable for use in a shipbuilding environment to automatically feed insulation pins and weld them in all positions with the short cycle process using either appropriate existing power/control units or a newly designed specific purpose power supply. |
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| Proceedings of the Conference on Surfaces and Interfaces in Mesoscopic Devices (SIMD) 1999, v27 n5/6, May/Jun 2000 |
04 FEB 2000 |
324 pages |
| Authors:
Karl Hess; D. K. Ferry; Jonathan Bird; ILLINOIS UNIV URBANA BECKMAN INST
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| Superlattices and Microstructures is a journal devoted to the science and technology of synthetic microstructures, microdevices, surfaces and interfaces. The last decade has seen rapid developments in the fabrication, characterization and conceptual understanding of synthetic microstructures in many different material systems including silicon, III-V and II-VI semiconductors, metals, ceramics and organics. The objective of this journal is to provide a common interdisciplinary platform for the publication of the latest research ... |
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| Dynamic Fracture Toughness Characterization of HY-100 Under-Matched Welds |
FEB 2000 |
92 pages |
| Authors:
Stephen M. Graham; Michael D. McLaughlin; NAVAL SURFACE WARFARE CENTER CARDEROCK DIV BETHESDA MD SURVIVABILITY STRUCTURES AND MATERIALS DIRECTORATE
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| Welds in marine structures are typically fabricated such that the yield strength of the weld metal is higher than the base plate (over-matched). Allowing the weld metal yield strength to be less than the base metal (under- matching) can increase productivity and weld metal toughness; however, there is some concern that under-matching increases the crack driving force and decreases the weld metal tearing resistance. This study examined fracture behavior of ... |
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Fabrication Metallurgy
