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Sample records for generation high strength

  1. Development of high strength high toughness third generation advanced high strength steels

    NASA Astrophysics Data System (ADS)

    Martis, Codrick John

    Third generation advanced high strength steels (AHSS's) are emerging as very important engineering materials for structural applications. These steels have high specific strength and thus will contribute significantly to weight reduction in automotive and other structural component. In this investigation two such low carbon low alloy steels (LCLA) with high silicon content (1.6-2wt %) has been developed. These two steel alloys were subjected to single step and two step austempering in the temperature range of 260-399°C to obtain desired microstructures and mechanical properties. Austempering heat treatment was carried out for 2 hours in a molten salt bath. The microstructures were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and optical metallography. Quantitative analysis was carried out by image analysis technique. The effect of austempering temperature on the mechanical properties of these two alloys was examined. The influence of microstructures on the mechanical properties of alloys was also studied. Austempering heat treatment resulted in fine carbide free bainitic ferrite and high carbon austenite microstructure in the samples austempered above Ms temperature, whereas tempered martensite and austenite microstructure was obtained in samples austempered below Ms temperature. Yield strength, tensile strength and fracture toughness were found to increase as the austempering temperature decreases, whereas ductility increases as the austempering temperature increases. Tensile strength in the range of 1276MPa -1658 MPa and the fracture toughness in the range of 80-141MPa√m were obtained in these two steels. Volume fractions of different phases present and their lath sizes are related to the mechanical properties. Austempered samples consisting of mixed microstructure of bainitic ferrite and tempered martensite phases resulted in the exceptional combination of strength and toughness.

  2. Formability Characterization of a New Generation High Strength Steels

    SciTech Connect

    Sriram Sadagopan; Dennis Urban; Chris Wong; Mai Huang; Benda Yan

    2003-05-16

    Advanced high strength steels (AHSS) are being progressively explored by the automotive industry all around the world for cost-effective solutions to accomplish vehicle lightweighting, improve fuel economy, and consequently reduce greenhouse emissions. Because of their inherent high strength, attractive crash energy management properties, and good formability, the effective use of AHSS such as Duel Phase and TRIP (Transformation Induced Plasticity) steels, will significantly contribute to vehicle lightweighting and fuel economy. To further the application of these steels in automotive body and structural parts, a good knowledge and experience base must be developed regarding the press formability of these materials. This project provides data on relevant intrinsic mechanical behavior, splitting limits, and springback behavior of several lots of mild steel, conventional high strength steel (HSS), advanced high strength steel (AHSS) and ultra-high strength steel (UHSS), supplied by the member companies of the Automotive Applications Committee (AAC) of the American Iron and Steel Institute (AISI). Two lots of TRIP600, which were supplied by ThyssenKrupp Stahl, were also included in the study. Since sheet metal forming encompasses a very diverse range of forming processes and deformation modes, a number of simulative tests were used to characterize the forming behavior of these steel grades. In general, it was found that formability, as determined by the different tests, decreased with increased tensile strength. Consistant with previous findings, the formability of TRIP600 was found to be exceptionally good for its tensile strength.

  3. Longitudinally polarized single-cycle terahertz pulses generated with high electric field strengths

    NASA Astrophysics Data System (ADS)

    Cliffe, M. J.; Graham, D. M.; Jamison, S. P.

    2016-05-01

    We demonstrate the generation of single-cycle longitudinally polarized terahertz pulses with field amplitudes in excess of 11 kV/cm using the interferometric recombination of two linearly polarized terahertz beams. High field strength transversely polarized pulses were generated by optical rectification in a matched pair of magnesium-oxide doped stoichiometric lithium niobate (MgO:SLN) crystals with a reversal in the χ333 ( 2 ) orientation. The discontinuity in χ333 ( 2 ) produces a polarity flip in the transverse field; the longitudinal field produced as a consequence of the transverse field discontinuity was measured in the far-field. Both the spatial and temporal profiles of the measured longitudinally polarized terahertz radiation were consistent with the propagation of the transverse discontinuity.

  4. Nanoscale surface analysis on second generation advanced high strength steel after hot dip galvanizing.

    PubMed

    Arndt, M; Duchoslav, J; Preis, K; Samek, L; Stifter, D

    2013-09-01

    Second generation advanced high strength steel is one promising material of choice for modern automotive structural parts because of its outstanding maximal elongation and tensile strength. Nonetheless there is still a lack of corrosion protection for this material due to the fact that cost efficient hot dip galvanizing cannot be applied. The reason for the insufficient coatability with zinc is found in the segregation of manganese to the surface during annealing and the formation of manganese oxides prior coating. This work analyses the structure and chemical composition of the surface oxides on so called nano-TWIP (twinning induced plasticity) steel on the nanoscopic scale after hot dip galvanizing in a simulator with employed analytical methods comprising scanning Auger electron spectroscopy (SAES), energy dispersive X-ray spectroscopy (EDX), and focused ion beam (FIB) for cross section preparation. By the combination of these methods, it was possible to obtain detailed chemical images serving a better understanding which processes exactly occur on the surface of this novel kind of steel and how to promote in the future for this material system galvanic protection. PMID:23404132

  5. High strength alloys

    SciTech Connect

    Maziasz, Phillip James; Shingledecker, John Paul; Santella, Michael Leonard; Schneibel, Joachim Hugo; Sikka, Vinod Kumar; Vinegar, Harold J.; John, Randy Carl; Kim, Dong Sub

    2012-06-05

    High strength metal alloys are described herein. At least one composition of a metal alloy includes chromium, nickel, copper, manganese, silicon, niobium, tungsten and iron. System, methods, and heaters that include the high strength metal alloys are described herein. At least one heater system may include a canister at least partially made from material containing at least one of the metal alloys. At least one system for heating a subterranean formation may include a tublar that is at least partially made from a material containing at least one of the metal alloys.

  6. High strength alloys

    SciTech Connect

    Maziasz, Phillip James; Shingledecker, John Paul; Santella, Michael Leonard; Schneibel, Joachim Hugo; Sikka, Vinod Kumar; Vinegar, Harold J; John, Randy Carl; Kim, Dong Sub

    2010-08-31

    High strength metal alloys are described herein. At least one composition of a metal alloy includes chromium, nickel, copper, manganese, silicon, niobium, tungsten and iron. System, methods, and heaters that include the high strength metal alloys are described herein. At least one heater system may include a canister at least partially made from material containing at least one of the metal alloys. At least one system for heating a subterranean formation may include a tubular that is at least partially made from a material containing at least one of the metal alloys.

  7. High strength composites evaluation

    SciTech Connect

    Marten, S.M.

    1992-02-01

    A high-strength, thick-section, graphite/epoxy composite was identified. The purpose of this development effort was to evaluate candidate materials and provide LANL with engineering properties. Eight candidate materials (Samples 1000, 1100, 1200, 1300, 1400, 1500, 1600, and 1700) were chosen for evaluation. The Sample 1700 thermoplastic material was the strongest overall.

  8. Electricity generation and nutrients removal from high-strength liquid manure by air-cathode microbial fuel cells.

    PubMed

    Lin, Hongjian; Wu, Xiao; Nelson, Chad; Miller, Curtis; Zhu, Jun

    2016-01-01

    Air-cathode microbial fuel cells (MFCs) are widely tested to recover electrical energy from waste streams containing organic matter. When high-strength wastewater, such as liquid animal manure, is used as a medium, inhibition on anode and cathode catalysts potentially impairs the effectiveness of MFC performance in power generation and pollutant removal. This study evaluated possible inhibitive effects of liquid swine manure components on MFC power generation, improved liquid manure-fed MFCs performance by pretreatment (dilution and selective adsorption), and modeled the kinetics of organic matter and nutrients removal kinetics. Parameters monitored included pH, conductivity, chemical oxygen demand (COD), volatile fatty acids (VFAs), total ammoniacal nitrogen (TAN), nitrite, nitrate, and phosphate concentrations. The removals of VFA and TAN were efficient, indicated by the short half-life times of 4.99 and 7.84 d, respectively. The mechanism for phosphate decrease was principally the salt precipitation on cathode, but the removal was incomplete after 42-d operation. MFC with an external resistor of 2.2 kΩ and fed with swine wastewater generated relatively small power (28.2 μW), energy efficiency (0.37%) and Coulombic efficiency (1.5%). Dilution of swine wastewater dramatically improved the power generation as the inhibitory effect was decreased. Zeolite and granular activated carbon were effective in the selective adsorption of ammonia or organic matter in swine wastewater, and so substantially improved the power generation, energy efficiency, and Coulombic efficiency. A smaller external resistor in the circuit was also observed to promote the organic matter degradation and thus to shorten the treatment time. Overall, air-cathode MFCs are promising for generating electrical power from livestock wastewater and meanwhile reducing the level of organic matter and nutrients. PMID:26654000

  9. AISI/DOE Technology Roadmap Program: Characterization of Fatigue and Crash Performance of New Generation High Strength Steels for Automotive Applications

    SciTech Connect

    Brenda Yan; Dennis Urban

    2003-04-21

    A 2-year project (2001-2002) to generate fatigue and high strain data for a new generation of high strength steels (HSS) has been completed in December 2002. The project tested eleven steel grades, including Dual Phase (DP) steels, Transformation-Induced Plasticity (TRIP) steels, Bake Hardenable (BH) steels, and conventional High Strength Low Alloy (HSLA) steels. All of these steels are of great interest in automotive industry due to the potential benefit in weight reduction, improved fuel economy, enhanced crash energy management and total system cost savings. Fatigue behavior includes strain controlled fatigue data notch sensitivity for high strength steels. High strain rate behavior includes stress-strain data for strain rates from 0.001/s to 1000/s, which are considered the important strain rate ranges for crash event. The steels were tested in two phases, seven were tested in Phase 1 and the remaining steels were tested in Phase. In a addition to the fatigue data and high st rain rate data generated for the steels studied in the project, analyses of the testing results revealed that Advanced High Strength Steels (AHSS) exhibit significantly higher fatigue strength and crash energy absorption capability than conventional HSS. TRIP steels exhibit exceptionally better fatigue strength than steels of similar tensile strength but different microstructure, for conditions both with or without notches present

  10. High strength ferritic alloy

    DOEpatents

    Hagel, William C.; Smidt, Frederick A.; Korenko, Michael K.

    1977-01-01

    A high-strength ferritic alloy useful for fast reactor duct and cladding applications where an iron base contains from about 9% to about 13% by weight chromium, from about 4% to about 8% by weight molybdenum, from about 0.2% to about 0.8% by weight niobium, from about 0.1% to about 0.3% by weight vanadium, from about 0.2% to about 0.8% by weight silicon, from about 0.2% to about 0.8% by weight manganese, a maximum of about 0.05% by weight nitrogen, a maximum of about 0.02% by weight sulfur, a maximum of about 0.02% by weight phosphorous, and from about 0.04% to about 0.12% by weight carbon.

  11. Production of high strength concrete

    SciTech Connect

    Peterman, M.B.; Carrasquillo, R.L.

    1986-01-01

    The criteria for selection of concrete materials and their proportions to producer uniform, economical, high strength concrete are presented in this book. The recommendations provided are based on a study of the interactions among components of plain concrete and mix proportions, and of their contribution to the compressive strength of high strength concrete. These recommendations will serve as guidelines to practicing engineers, in the selection of materials and their proportions for the production of high strength concrete. Increasing demands for improved efficiency and reduced construction costs have resulted in engineers beginning to design large structures using higher strength concrete at higher stress levels. There are definite advantages, both technical and economical, in using high strength concrete. For example, for a given cross section, prestresses concrete bridge girders can carry greater service loads across longer spans if made using high strength concrete. In addition, cost comparisons have shown that the savings obtained are significantly greater than the added cost of the higher quality concrete.

  12. High-Hot-Strength Ceramic Fibers

    NASA Technical Reports Server (NTRS)

    Sayir, Ali; Matson, Lawrence E.

    1994-01-01

    Continuous fibers consisting of laminae of alumina and yttrium aluminum garnet offer exceptionally high strength, resistance to creep, and chemical stability at high temperatures. These fibers exceed tensile strength of sapphire fibers. Leading candidates for reinforcement of intermetallic-matrix composites in exhaust nozzles of developmental high-speed civil transport aircraft engines. Other applications are in aerospace, automotive, chemical-process, and power-generation industries.

  13. Development of high strength, high temperature ceramics

    NASA Technical Reports Server (NTRS)

    Hall, W. B.

    1982-01-01

    Improvement in the high-pressure turbopumps, both fuel and oxidizer, in the Space Shuttle main engine were considered. The operation of these pumps is limited by temperature restrictions of the metallic components used in these pumps. Ceramic materials that retain strength at high temperatures and appear to be promising candidates for use as turbine blades and impellers are discussed. These high strength materials are sensitive to many related processing parameters such as impurities, sintering aids, reaction aids, particle size, processing temperature, and post thermal treatment. The specific objectives of the study were to: (1) identify and define the processing parameters that affect the properties of Si3N4 ceramic materials, (2) design and assembly equipment required for processing high strength ceramics, (3) design and assemble test apparatus for evaluating the high temperature properties of Si3N4, and (4) conduct a research program of manufacturing and evaluating Si3N4 materials as applicable to rocket engine applications.

  14. High strength high modulus ceramic fiber

    NASA Technical Reports Server (NTRS)

    Fetterolf, R. N.

    1972-01-01

    Low cost method was developed for producing high strength, high modulus, continuous ceramic oxide fibers. Process transforms inexpensive metallic salts into syrup-like liquids that can be fiberized at room temperatures. Resulting salt fibers are then converted to oxides by calcination at relatively low temperatures.

  15. High strength, tough alloy steel

    DOEpatents

    Thomas, Gareth; Rao, Bangaru V. N.

    1979-01-01

    A high strength, tough alloy steel is formed by heating the steel to a temperature in the austenite range (1000.degree.-1100.degree. C.) to form a homogeneous austenite phase and then cooling the steel to form a microstructure of uniformly dispersed dislocated martensite separated by continuous thin boundary films of stabilized retained austenite. The steel includes 0.2-0.35 weight % carbon, at least 1% and preferably 3-4.5% chromium, and at least one other substitutional alloying element, preferably manganese or nickel. The austenite film is stable to subsequent heat treatment as by tempering (below 300.degree. C.) and reforms to a stable film after austenite grain refinement.

  16. High strength and high toughness steel

    DOEpatents

    Parker, Earl R.; Zackay, Victor F.

    1979-01-01

    A structural steel which possess both high strength and high toughness and has particular application of cryogenic uses. The steel is produced by the utilization of thermally induced phase transformation following heating in a three-phase field in iron-rich alloys of the Fe-Ni-Ti system, with a preferred composition of 12% nickel, 0.5% titanium, the remainder being iron.

  17. High strength, high ductility low carbon steel

    DOEpatents

    Koo, Jayoung; Thomas, Gareth

    1978-01-01

    A high strength, high ductility low carbon steel consisting essentially of iron, 0.05-0.15 wt% carbon, and 1-3 wt% silicon. Minor amounts of other constituents may be present. The steel is characterized by a duplex ferrite-martensite microstructure in a fibrous morphology. The microstructure is developed by heat treatment consisting of initial austenitizing treatment followed by annealing in the (.alpha. + .gamma.) range with intermediate quenching.

  18. Terapascal static pressure generation with ultrahigh yield strength nanodiamond

    PubMed Central

    Dubrovinskaia, Natalia; Dubrovinsky, Leonid; Solopova, Natalia A.; Abakumov, Artem; Turner, Stuart; Hanfland, Michael; Bykova, Elena; Bykov, Maxim; Prescher, Clemens; Prakapenka, Vitali B.; Petitgirard, Sylvain; Chuvashova, Irina; Gasharova, Biliana; Mathis, Yves-Laurent; Ershov, Petr; Snigireva, Irina; Snigirev, Anatoly

    2016-01-01

    Studies of materials’ properties at high and ultrahigh pressures lead to discoveries of unique physical and chemical phenomena and a deeper understanding of matter. In high-pressure research, an achievable static pressure limit is imposed by the strength of available strong materials and design of high-pressure devices. Using a high-pressure and high-temperature technique, we synthesized optically transparent microballs of bulk nanocrystalline diamond, which were found to have an exceptional yield strength (~460 GPa at a confining pressure of ~70 GPa) due to the unique microstructure of bulk nanocrystalline diamond. We used the nanodiamond balls in a double-stage diamond anvil cell high-pressure device that allowed us to generate static pressures beyond 1 TPa, as demonstrated by synchrotron x-ray diffraction. Outstanding mechanical properties (strain-dependent elasticity, very high hardness, and unprecedented yield strength) make the nanodiamond balls a unique device for ultrahigh static pressure generation. Structurally isotropic, homogeneous, and made of a low-Z material, they are promising in the field of x-ray optical applications. PMID:27453944

  19. Terapascal static pressure generation with ultrahigh yield strength nanodiamond.

    PubMed

    Dubrovinskaia, Natalia; Dubrovinsky, Leonid; Solopova, Natalia A; Abakumov, Artem; Turner, Stuart; Hanfland, Michael; Bykova, Elena; Bykov, Maxim; Prescher, Clemens; Prakapenka, Vitali B; Petitgirard, Sylvain; Chuvashova, Irina; Gasharova, Biliana; Mathis, Yves-Laurent; Ershov, Petr; Snigireva, Irina; Snigirev, Anatoly

    2016-07-01

    Studies of materials' properties at high and ultrahigh pressures lead to discoveries of unique physical and chemical phenomena and a deeper understanding of matter. In high-pressure research, an achievable static pressure limit is imposed by the strength of available strong materials and design of high-pressure devices. Using a high-pressure and high-temperature technique, we synthesized optically transparent microballs of bulk nanocrystalline diamond, which were found to have an exceptional yield strength (~460 GPa at a confining pressure of ~70 GPa) due to the unique microstructure of bulk nanocrystalline diamond. We used the nanodiamond balls in a double-stage diamond anvil cell high-pressure device that allowed us to generate static pressures beyond 1 TPa, as demonstrated by synchrotron x-ray diffraction. Outstanding mechanical properties (strain-dependent elasticity, very high hardness, and unprecedented yield strength) make the nanodiamond balls a unique device for ultrahigh static pressure generation. Structurally isotropic, homogeneous, and made of a low-Z material, they are promising in the field of x-ray optical applications. PMID:27453944

  20. High-Strength Glass Fibers and Markets

    NASA Astrophysics Data System (ADS)

    Hausrath, Robert L.; Longobardo, Anthony V.

    High-strength glass fibers play a crucial role in composite applications requiring combinations of strength, modulus, and high-temperature stability. Compositions in the high-strength glass group include S-glass and R-glass, which are used for applications requiring physical properties that cannot be satisfied by conventional E-glass. Additional compositions are also available for specialized applications requiring extreme performance in any one area. The main competition for high-strength glasses in the marketplace comes from carbon and polymer fibers. Ultimately, the product of choice is based on a compromise between cost and performance and will vary depending on the application.

  1. High-Strength Glass for Solar Applications

    NASA Technical Reports Server (NTRS)

    Bouquet, F. L.

    1987-01-01

    Technology for strengthening thin sections reviewed. Report reviews technology of high-strength glass for such solar applications as heat collectors, reflectors, and photovoltaic arrays. Discusses most feasible methods - heat strengthening and chemical strengthening of increasing strength of glass for solar-energy use. Also estimates cost and availability of high-strength glass and considers physical characteristics, amenability to back-silvering, and effects of atmospheric contamination.

  2. High strength air-dried aerogels

    DOEpatents

    Coronado, Paul R.; Satcher, Jr., Joe H.

    2012-11-06

    A method for the preparation of high strength air-dried organic aerogels. The method involves the sol-gel polymerization of organic gel precursors, such as resorcinol with formaldehyde (RF) in aqueous solvents with R/C ratios greater than about 1000 and R/F ratios less than about 1:2.1. Using a procedure analogous to the preparation of resorcinol-formaldehyde (RF) aerogels, this approach generates wet gels that can be air dried at ambient temperatures and pressures. The method significantly reduces the time and/or energy required to produce a dried aerogel compared to conventional methods using either supercritical solvent extraction. The air dried gel exhibits typically less than 5% shrinkage.

  3. High-strength, low-alloy steels.

    PubMed

    Rashid, M S

    1980-05-23

    High-strength, low-alloy (HSLA) steels have nearly the same composition as plain carbon steels. However, they are up to twice as strong and their greater load-bearing capacity allows engineering use in lighter sections. Their high strength is derived from a combination of grain refinement; precipitation strengthening due to minor additions of vanadium, niobium, or titanium; and modifications of manufacturing processes, such as controlled rolling and controlled cooling of otherwise essentially plain carbon steel. HSLA steels are less formable than lower strength steels, but dualphase steels, which evolved from HSLA steels, have ferrite-martensite microstructures and better formability than HSLA steels of similar strength. This improved formability has substantially increased the utilization potential of high-strength steels in the manufacture of complex components. This article reviews the development of HSLA and dual-phase steels and discusses the effects of variations in microstructure and chemistry on their mechanical properties. PMID:17772810

  4. High-strength magnetic materials

    NASA Technical Reports Server (NTRS)

    Detert, K.

    1970-01-01

    Two new precipitation-hardened magnetic alloys are suitable for operation in 800 to 1600 deg F range. One is a martensitic alloy and the other a cobalt-based alloy. They possess improved creep resistance and have application in high temperature inductors and alternators.

  5. High-Strength, Superelastic Compounds

    NASA Technical Reports Server (NTRS)

    Stanford, Malcolm; Noebe, Ronald; Dellacorte, Christopher; Bigelow, Glen; Thomas, Fransua

    2013-01-01

    can be used in the heat treatment process, less energy will be consumed, and there will be less dimensional distortion and quench cracking. This results in fewer scrap parts, less material waste from large amounts of material removal, and fewer machining steps to rework parts that are out of specification. This material has a combination of properties that have been previously unobtainable. The material has a Young s modulus of approximately 95 GPa (about half that of conventional steels), moderate density (10 to 15% lower than conventional steels), excellent corrosion resistance, and high hardness (58 to 62 HRC). These properties make this material uniquely suited for advanced bearings.

  6. Development of High Specific Strength Envelope Materials

    NASA Astrophysics Data System (ADS)

    Komatsu, Keiji; Sano, Masa-Aki; Kakuta, Yoshiaki

    Progress in materials technology has produced a much more durable synthetic fabric envelope for the non-rigid airship. Flexible materials are required to form airship envelopes, ballonets, load curtains, gas bags and covering rigid structures. Polybenzoxazole fiber (Zylon) and polyalirate fiber (Vectran) show high specific tensile strength, so that we developed membrane using these high specific tensile strength fibers as a load carrier. The main material developed is a Zylon or Vectran load carrier sealed internally with a polyurethane bonded inner gas retention film (EVOH). The external surface provides weather protecting with, for instance, a titanium oxide integrated polyurethane or Tedlar film. The mechanical test results show that tensile strength 1,000 N/cm is attained with weight less than 230g/m2. In addition to the mechanical properties, temperature dependence of the joint strength and solar absorptivity and emissivity of the surface are measured. 

  7. High toughness-high strength iron alloy

    NASA Technical Reports Server (NTRS)

    Stephens, J. R.; Witzke, W. R. (Inventor)

    1980-01-01

    An iron alloy is provided which exhibits strength and toughness characteristics at cryogenic temperatures. The alloy consists essentially of about 10 to 16 percent by weight nickel, about 0.1 to 1.0 percent by weight aluminum, and 0 to about 3 percent by weight copper, with the balance being essentially iron. The iron alloy is produced by a process which includes cold rolling at room temperature and subsequent heat treatment.

  8. High strength cast aluminum alloy development

    NASA Astrophysics Data System (ADS)

    Druschitz, Edward A.

    The goal of this research was to understand how chemistry and processing affect the resulting microstructure and mechanical properties of high strength cast aluminum alloys. Two alloy systems were investigated including the Al-Cu-Ag and the Al-Zn-Mg-Cu systems. Processing variables included solidification under pressure (SUP) and heat treatment. This research determined the range in properties that can be achieved in BAC 100(TM) (Al-Cu micro-alloyed with Ag, Mn, Zr, and V) and generated sufficient property data for design purposes. Tensile, stress corrosion cracking, and fatigue testing were performed. CuAl2 and Al-Cu-Fe-Mn intermetallics were identified as the ductility limiting flaws. A solution treatment of 75 hours or longer was needed to dissolve most of the intermetallic CuAl 2. The Al-Cu-Fe-Mn intermetallic was unaffected by heat treatment. These results indicate that faster cooling rates, a reduction in copper concentration and a reduction in iron concentration might increase the ductility of the alloy by decreasing the size and amount of the intermetallics that form during solidification. Six experimental Al-Zn-Mg-Cu series alloys were produced. Zinc concentrations of 8 and 12wt% and Zn/Mg ratios of 1.5 to 5.5 were tested. Copper was held constant at 0.9%. Heat treating of the alloys was optimized for maximum hardness. Al-Zn-Mg-Cu samples were solution treated at 441°C (826°F) for 4 hours before ramping to 460°C (860°F) for 75 hours and then aged at 120°C (248°F) for 75 hours. X-ray diffraction showed that the age hardening precipitates in most of these alloys was the T phase (Mg32Zn 31.9Al17.1). Tensile testing of the alloys showed that the best mechanical properties were obtained in the lowest alloy condition. Chilled Al-8.2Zn-1.4Mg-0.9Cu solidified under pressure resulted in an alloy with a yield strength of 468MPa (68ksi), tensile strength of 525MPa (76ksi) and an elongation of 9%.

  9. Yield strength of molybdenum at high pressures.

    PubMed

    Jing, Qiumin; Bi, Yan; Wu, Qiang; Jing, Fuqian; Wang, Zhigang; Xu, Jian; Jiang, Sheng

    2007-07-01

    In the diamond anvil cell technology, the pressure gradient approach is one of the three major methods in determining the yield strength for various materials at high pressures. In the present work, by in situ measuring the thickness of the sample foil, we have improved the traditional technique in this method. Based on this modification, the yield strength of molybdenum at pressures has been measured. Our main experimental conclusions are as follows: (1) The measured yield strength data for three samples with different initial thickness (100, 250, and 500 microm) are in good agreement above a peak pressure of 10 GPa. (2) The measured yield strength can be fitted into a linear formula Y=0.48(+/-0.19)+0.14(+/-0.01)P (Y and P denote the yield strength and local pressure, respectively, both of them are in gigapascals) in the local pressure range of 8-21 GPa. This result is in good agreement with both Y=0.46+0.13P determined in the pressure range of 5-24 GPa measured by the radial x-ray diffraction technique and the previous shock wave data below 10 GPa. (3) The zero-pressure yield strength of Mo is 0.5 GPa when we extrapolate our experimental data into the ambient pressure. It is close to the tensile strength of 0.7 GPa determined by Bridgman [Phys. Rev. 48, 825 (1934)] previously. The modified method described in this article therefore provides the confidence in determination of the yield strength at high pressures. PMID:17672772

  10. Reinforcing aluminum alloys with high strength fibers

    NASA Technical Reports Server (NTRS)

    Kolpashnikov, A. I.; Manuylov, V. F.; Chukhin, B. D.; Shiryayev, Y. V.; Shurygin, A. S.

    1982-01-01

    A study is made of the possibility of reinforcing aluminum and aluminum based alloys with fibers made of high strength steel wire. The method of introducing the fibers is described in detail. Additional strengthening by reinforcement of the high alloy system Al - An - Mg was investigated.

  11. Method for producing high dielectric strength microvalves

    SciTech Connect

    Kirby, Brian J.; Reichmuth, David S.; Shepodd, Timothy J.

    2006-04-04

    A microvalve having a cast-in-place and lithographically shaped mobile, polymer monolith for fluid flow control in microfluidic devices and method of manufacture. The microvalve contains a porous fluorinated polymer monolithic element whose pores are filled with an electrically insulating, high dielectric strength fluid, typically a perfluorinated liquid. This combination provides a microvalve that combines high dielectric strength with extremely low electrical conductivity. These microvalves have been shown to have resistivities of at least 100 G.OMEGA. and are compatible with solvents such as water at a pH between 2.7 and 9.0, 1-1 propanol, acetonitrile, and acetone.

  12. Alloy Design and Development of Cast Cr-W-V Ferritic Steels for Improved High-Temperature Strength for Power Generation Applications

    SciTech Connect

    Klueh, R L; Maziasz, P J; Vitek, J M; Evans, N D; Hashimoto, N

    2006-09-23

    Economic and environmental concerns demand that the power-generation industry seek increased efficiency for gas turbines. Higher efficiency requires higher operating temperatures, with the objective temperature for the hottest sections of new systems {approx} 593 C, and increasing to {approx} 650 C. Because of their good thermal properties, Cr-Mo-V cast ferritic steels are currently used for components such as rotors, casings, pipes, etc., but new steels are required for the new operating conditions. The Oak Ridge National Laboratory (ORNL) has developed new wrought Cr-W-V steels with 3-9% Cr, 2-3% W, 0.25% V (compositions are in wt.%), and minor amounts of additional elements. These steels have the strength and toughness required for turbine applications. Since cast alloys are expected to behave differently from wrought material, work was pursued to develop new cast steels based on the ORNL wrought compositions. Nine casting test blocks with 3, 9, and 11% Cr were obtained. Eight were Cr-W-V-Ta-type steels based on the ORNL wrought steels; the ninth was COST CB2, a 9Cr-Mo-Co-V-Nb cast steel, which was the most promising cast steel developed in a European alloy-development program. The COST CB2 was used as a control to which the new compositions were compared, and this also provided a comparison between Cr-W-V-Ta and Cr-Mo-V-Nb compositions. Heat treatment studies were carried out on the nine castings to determine normalizing-and-tempering treatments. Microstructures were characterized by both optical and transmission electron microscopy (TEM). Tensile, impact, and creep tests were conducted. Test results on the first nine cast steel compositions indicated that properties of the 9Cr-Mo-Co-V-Nb composition of COST CB2 were better than those of the 3Cr-, 9Cr-, and 11Cr-W-V-Ta steels. Analysis of the results of this first iteration using computational thermodynamics raised the question of the effectiveness in cast steels of the Cr-W-V-Ta combination versus the Cr

  13. Corrosion fatigue of high strength fastener materials in seawater

    NASA Astrophysics Data System (ADS)

    Tipton, D. G.

    1983-12-01

    Environmental effects which significantly reduce the fatigue life of metals are discussed. Corrosion fatigue is a major concern in the engineering application of high strength fasteners in marine environments. The corrosion fatigue failure of an AISI 41L4O high strength steel blade to hub attachment bolt at the MOD-OA 200 kW wind turbine generator was investigated. The reduction of fatigue strength of AISI 41L4O in marine environments and to obtain similar corrosion fatigue data for candidate replacement materials was studied. The AISI 4140, PH 13-8Mo stainless steel, alloy 718 and alloy MP-35N were tested in axial fatigue at a frequency of 20 Hz in dry air and natural seawater. The fatigue data are fitted by regression equations to allow determination of fatigue strength for a given number of cycles to failure.

  14. Corrosion fatigue of high strength fastener materials in seawater

    NASA Technical Reports Server (NTRS)

    Tipton, D. G.

    1983-01-01

    Environmental effects which significantly reduce the fatigue life of metals are discussed. Corrosion fatigue is a major concern in the engineering application of high strength fasteners in marine environments. The corrosion fatigue failure of an AISI 41L4O high strength steel blade to hub attachment bolt at the MOD-OA 200 kW wind turbine generator was investigated. The reduction of fatigue strength of AISI 41L4O in marine environments and to obtain similar corrosion fatigue data for candidate replacement materials was studied. The AISI 4140, PH 13-8Mo stainless steel, alloy 718 and alloy MP-35N were tested in axial fatigue at a frequency of 20 Hz in dry air and natural seawater. The fatigue data are fitted by regression equations to allow determination of fatigue strength for a given number of cycles to failure.

  15. Spontaneous Radiation Emission from Short, High Field Strength Insertion Devices

    SciTech Connect

    Geoffrey Krafft

    2005-09-15

    Since the earliest papers on undulaters were published, it has been known how to calculate the spontaneous emission spectrum from ''short'' undulaters when the magnetic field strength parameter is small compared to unity, or in ''single'' frequency sinusoidal undulaters where the magnetic field strength parameter is comparable to or larger than unity, but where the magnetic field amplitude is constant throughout the undulater. Fewer general results have been obtained in the case where the insertion device is both short, i.e., the magnetic field strength parameter changes appreciably throughout the insertion device, and the magnetic field strength is high enough that ponderomotive effects, radiation retardation, and harmonic generation are important physical phenomena. In this paper a general method is presented for calculating the radiation spectrum for short, high-field insertion devices. It is used to calculate the emission from some insertion device designs of recent interest.

  16. Springback analysis of ultra high strength steel

    NASA Astrophysics Data System (ADS)

    Tenma, Kenji; Kina, Futoshi; Suzuki, Wataru

    2013-12-01

    It is an inevitable trend in the automotive industry to apply more and more high strength steels and even ultra-high strength steels. Even though these materials are more difficult to process the development time of forming tools must be reduced. In order to keep the development time under control, simulation tools are used to verify the forming process in advance. At Aoi Machine Industry a project has been executed to accurately simulate springback of ultra-high strength steels in order to reduce the tool tryout time. In the first phase of the project the simulation settings were optimized based on B-Pillar model A made of Dual Phase 980. In the second phase, it was verified with B-Pillar model B whether these simulation settings were usable as general setting. Results showed that with the right settings it is very well possible to accurately simulate springback of ultra-high strength steels. In the third phase the project the stamping of a B-Pillar of Dual Phase 1180 was studied.

  17. High strength composites evaluation. Final report

    SciTech Connect

    Marten, S.M.

    1992-02-01

    A high-strength, thick-section, graphite/epoxy composite was identified. The purpose of this development effort was to evaluate candidate materials and provide LANL with engineering properties. Eight candidate materials (Samples 1000, 1100, 1200, 1300, 1400, 1500, 1600, and 1700) were chosen for evaluation. The Sample 1700 thermoplastic material was the strongest overall.

  18. High-strength mineralized collagen artificial bone

    NASA Astrophysics Data System (ADS)

    Qiu, Zhi-Ye; Tao, Chun-Sheng; Cui, Helen; Wang, Chang-Ming; Cui, Fu-Zhai

    2014-03-01

    Mineralized collagen (MC) is a biomimetic material that mimics natural bone matrix in terms of both chemical composition and microstructure. The biomimetic MC possesses good biocompatibility and osteogenic activity, and is capable of guiding bone regeneration as being used for bone defect repair. However, mechanical strength of existing MC artificial bone is too low to provide effective support at human load-bearing sites, so it can only be used for the repair at non-load-bearing sites, such as bone defect filling, bone graft augmentation, and so on. In the present study, a high strength MC artificial bone material was developed by using collagen as the template for the biomimetic mineralization of the calcium phosphate, and then followed by a cold compression molding process with a certain pressure. The appearance and density of the dense MC were similar to those of natural cortical bone, and the phase composition was in conformity with that of animal's cortical bone demonstrated by XRD. Mechanical properties were tested and results showed that the compressive strength was comparable to human cortical bone, while the compressive modulus was as low as human cancellous bone. Such high strength was able to provide effective mechanical support for bone defect repair at human load-bearing sites, and the low compressive modulus can help avoid stress shielding in the application of bone regeneration. Both in vitro cell experiments and in vivo implantation assay demonstrated good biocompatibility of the material, and in vivo stability evaluation indicated that this high-strength MC artificial bone could provide long-term effective mechanical support at human load-bearing sites.

  19. Making High-Tensile-Strength Amalgam Components

    NASA Technical Reports Server (NTRS)

    Grugel, Richard

    2008-01-01

    Structural components made of amalgams can be made to have tensile strengths much greater than previously known to be possible. Amalgams, perhaps best known for their use in dental fillings, have several useful attributes, including room-temperature fabrication, corrosion resistance, dimensional stability, and high compressive strength. However, the range of applications of amalgams has been limited by their very small tensile strengths. Now, it has been discovered that the tensile strength of an amalgam depends critically on the sizes and shapes of the particles from which it is made and, consequently, the tensile strength can be greatly increased through suitable choice of the particles. Heretofore, the powder particles used to make amalgams have been, variously, in the form of micron-sized spheroids or flakes. The tensile reinforcement contributed by the spheroids and flakes is minimal because fracture paths simply go around these particles. However, if spheroids or flakes are replaced by strands having greater lengths, then tensile reinforcement can be increased significantly. The feasibility of this concept was shown in an experiment in which electrical copper wires, serving as demonstration substitutes for copper powder particles, were triturated with gallium by use of a mortar and pestle and the resulting amalgam was compressed into a mold. The tensile strength of the amalgam specimen was then measured and found to be greater than 10(exp 4) psi (greater than about 69 MPa). Much remains to be done to optimize the properties of amalgams for various applications through suitable choice of starting constituents and modification of the trituration and molding processes. The choice of wire size and composition are expected to be especially important. Perusal of phase diagrams of metal mixtures could give insight that would enable choices of solid and liquid metal constituents. Finally, whereas heretofore, only binary alloys have been considered for amalgams

  20. Hydrogen trapping in high-strength steels

    SciTech Connect

    Pound, B.G.

    1998-10-09

    Hydrogen trapping in three high-strength steels -- AerMet 100 and AISI 4340 and H11 -- was studied using a potentiostatic pulse technique. Irreversible trapping constants (k) and hydrogen entry fluxes were determined for these alloys in 1 mol/1 acetic acid/1 mol/1 sodium acetate. The order of the k values for the three steels and two 18Ni maraging steels previously studies inversely parallels their threshold stress intensities for stress corrosion cracking (K{sub 1SCC}). Irreversible trapping in AerMet 100 varies with aging temperature and appears to depend on the type of carbide (Fe{sub 3}C or M{sub 2}C) present. For 4340 steel, k can be correlated with K{sub 1SCC} over a range of yield strengths. The change in k is consistent with a change in the principal type of irreversible trap from matrix boundaries to incoherent Fe{sub 3}C. The principal irreversible traps in H11 at high yield strengths are thought to be similar to those in 4340 steel.

  1. High-strength iron aluminide alloys

    SciTech Connect

    McKamey, C.G.; Maziasz, P.J.

    1996-06-01

    Past studies have shown that binary Fe{sub 3}Al possesses low creep-rupture strength compared to many other alloys, with creep-rupture lives of less than 5 h being reported for tests conducted at 593{degrees}C and 207 MPa. The combination of poor creep resistance and low room-temperature tensile ductility due to a susceptibility to environmentally-induced dynamic hydrogen embrittlement has limited use of these alloys for structural applications despite their excellent corrosion properties. With regard to the ductility problem, alloy development efforts have produced significant improvements, with ductilities of 10-20% and tensile yield strengths as high as 500 MPa being reported. Likewise, initial improvements in creep resistance have been realized through small additions of Mo, Nb, and Zr.

  2. Thermophilic anaerobic digestion of high strength wastewaters

    SciTech Connect

    Wiegant, W.M.; Claassen, J.A.; Lettinga, G.

    1985-09-01

    Investigations on the thermophilic anaerobic treatment of high-strength wastewaters (14-65 kg COD/mT) are presented. Vinasse, the wastewater of alcohol distilleries, was used as an example of such wastewaters. Semicontinuously fed digestion experiments at high retention times revealed that the effluent quality of digestion at 55C is comparable with that at 30C at similar loading rates. The amount of methane formed per kilogram of vinasse drops almost linearly with increasing vinasse concentrations. The treatment of vinasse was also investigated using upflow anaerobic sludge blanket (UASB) reactors.

  3. HIGH STRENGTH CONTROL RODS FOR NEUTRONIC REACTORS

    DOEpatents

    Lustman, B.; Losco, E.F.; Cohen, I.

    1961-07-11

    Nuclear reactor control rods comprised of highly compressed and sintered finely divided metal alloy panticles and fine metal oxide panticles substantially uniformly distributed theretbrough are described. The metal alloy consists essentially of silver, indium, cadmium, tin, and aluminum, the amount of each being present in centain percentages by weight. The oxide particles are metal oxides of the metal alloy composition, the amount of oxygen being present in certain percentages by weight and all the oxygen present being substantially in the form of metal oxide. This control rod is characterized by its high strength and resistance to creep at elevated temperatures.

  4. High-strength iron aluminide alloys

    SciTech Connect

    McKamey, C.G.; Marrero-Santos, Y.; Maziasz, P.J.

    1995-06-01

    Past studies have shown that binary Fe{sub 3}Al possesses low creep-rupture strength compared to many other alloys, with creep-rupture lives of less than 5 h being reported for tests conducted at 593{degrees}C and 207 MPa. The combination of poor creep resistance and low room-temperature tensile density due to a susceptibility to environmentally-induced dynamic hydrogen embrittlement has limited use of these alloys for structural applications, despite their excellent corrosion properties. Improvements in room temperature tensile ductility have been realized mainly through alloying effects, changes in thermomechanical processing to control microstructure, and by control of the specimen`s surface condition. Ductilities of 10-20% and tensile yield strengths as high as 500 MPa have been reported. In terms of creep-rupture strength, small additions of Mo, Nb, and Zr have produced significant improvements, but at the expense of weldability and room-temperature tensile ductility. Recently an alloy containing these additions, designated FA-180, was shown to exhibit a creep-rupture life of over 2000 h after a heat treatment of 1 h at 1150{degrees}C. This study presents the results of creep-rupture tests at various test temperatures and stresses and discusses the results as part of our effort to understand the strengthening mechanisms involved with heat treatment at 1150{degrees}C.

  5. High power microwave generator

    DOEpatents

    Ekdahl, C.A.

    1983-12-29

    A microwave generator efficiently converts the energy of an intense relativistic electron beam (REB) into a high-power microwave emission using the Smith-Purcell effect which is related to Cerenkov radiation. Feedback for efficient beam bunching and high gain is obtained by placing a cylindrical Smith-Purcell transmission grating on the axis of a toroidal resonator. High efficiency results from the use of a thin cold annular highly-magnetized REB that is closely coupled to the resonant structure.

  6. High power microwave generator

    DOEpatents

    Ekdahl, Carl A.

    1986-01-01

    A microwave generator efficiently converts the energy of an intense relativistic electron beam (REB) into a high-power microwave emission using the Smith-Purcell effect which is related to Cerenkov radiation. Feedback for efficient beam bunching and high gain is obtained by placing a cylindrical Smith-Purcell transmission grating on the axis of a toroidal resonator. High efficiency results from the use of a thin cold annular highly-magnetized REB that is closely coupled to the resonant structure.

  7. Protective claddings for high strength chromium alloys

    NASA Technical Reports Server (NTRS)

    Collins, J. F.

    1971-01-01

    The application of a Cr-Y-Hf-Th alloy as a protective cladding for a high strength chromium alloy was investigated for its effectiveness in inhibiting nitrogen embrittlement of a core alloy. Cladding was accomplished by a combination of hot gas pressure bonding and roll cladding techniques. Based on bend DBTT, the cladding alloy was effective in inhibiting nitrogen embrittlement of the chromium core alloy for up to 720 ks (200hours) in air at 1422 K (2100 F). A significant increase in the bend DBTT occurred with longer time exposures at 1422 K or short time exposures at 1589 K (2400 F).

  8. High Voltage Seismic Generator

    NASA Astrophysics Data System (ADS)

    Bogacz, Adrian; Pala, Damian; Knafel, Marcin

    2015-04-01

    This contribution describes the preliminary result of annual cooperation of three student research groups from AGH UST in Krakow, Poland. The aim of this cooperation was to develop and construct a high voltage seismic wave generator. Constructed device uses a high-energy electrical discharge to generate seismic wave in ground. This type of device can be applied in several different methods of seismic measurement, but because of its limited power it is mainly dedicated for engineering geophysics. The source operates on a basic physical principles. The energy is stored in capacitor bank, which is charged by two stage low to high voltage converter. Stored energy is then released in very short time through high voltage thyristor in spark gap. The whole appliance is powered from li-ion battery and controlled by ATmega microcontroller. It is possible to construct larger and more powerful device. In this contribution the structure of device with technical specifications is resented. As a part of the investigation the prototype was built and series of experiments conducted. System parameter was measured, on this basis specification of elements for the final device were chosen. First stage of the project was successful. It was possible to efficiently generate seismic waves with constructed device. Then the field test was conducted. Spark gap wasplaced in shallowborehole(0.5 m) filled with salt water. Geophones were placed on the ground in straight line. The comparison of signal registered with hammer source and sparker source was made. The results of the test measurements are presented and discussed. Analysis of the collected data shows that characteristic of generated seismic signal is very promising, thus confirms possibility of practical application of the new high voltage generator. The biggest advantage of presented device after signal characteristics is its size which is 0.5 x 0.25 x 0.2 m and weight approximately 7 kg. This features with small li-ion battery makes

  9. Microstructures in laser welded high strength steels

    NASA Astrophysics Data System (ADS)

    Rizzi, P.; Bellingeri, S.; Massimino, F.; Baldissin, D.; Battezzati, L.

    2009-01-01

    In this work, the effect of laser welding on the microstructure was studied for three Advanced High Strength Steels: transformation induced plasticity steel (TRIP), dual phase steel (DP) and martensitic steel. Two sheets of the same steel were laser welded and a microstructural study was performed by optical microscopy, scanning electron microscopy and X-ray diffraction. For all samples the welded zone was constituted by martensite and the heat affected zone shows a continuous change in microstructure depending on temperatures reached and on the different cooling rates. The change in mechanical properties in the welded area was followed by Vickers micro-hardness measurements. Quasi binary phase diagrams were calculated and, according to position of T0 lines, it was deduced that austenite is the primary phase forming during rapid solidification for all steels.

  10. High strength ferritic alloy-D53

    DOEpatents

    Hagel, William C.; Smidt, Frederick A.; Korenko, Michael K.

    1977-01-01

    A high strength ferritic alloy is described having from about 0.2% to about 0.8% by weight nickel, from about 2.5% to about 3.6% by weight chromium, from about 2.5% to about 3.5% by weight molybdenum, from about 0.1% to about 0.5% by weight vanadium, from about 0.1% to about 0.5% by weight silicon, from about 0.1% to about 0.6% by weight manganese, from about 0.12% to about 0.20% by weight carbon, from about 0.02% to about 0.1% by weight boron, a maximum of about 0.05% by weight nitrogen, a maximum of about 0.02% by weight phosphorous, a maximum of about 0.02% by weight sulfur, and the balance iron.

  11. Welding High Strength Modern Line Pipe Steel

    NASA Astrophysics Data System (ADS)

    Goodall, Graeme Robertson

    The effect of modern mechanized girth welding on high strength line pipe has been investigated. The single cycle grain coarsened heat affected zone in three grade 690 line pipe steels and a grade 550 steel has been simulated using a Gleeble thermo-mechanical simulator. The continuous cooling transformation diagrams applicable to the grain coarsened heat affected zone resulting from a range of heat inputs applicable to modern mechanized welding have been established by dilatometry and metallography. The coarse grained heat affected zone was found to transform to lath martensite, bainite, and granular bainite depending on the cooling rate. The impact toughness of the steels was measured using Charpy impact toughness and compared to the toughness of the grain coarsened heat affected zone corresponding to a welding thermal cycle. The ductile to brittle transition temperature was found to be lowest for the steel with the highest hardenability. The toughness resulting from three different thermal cycles including a novel interrupted intercritically reheated grain coarsened (NTR ICR GC HAZ) that can result from dual torch welding at fast travel speed and close torch spacing have been investigated. All of the thermally HAZ regions showed reduced toughness that was attributed to bainitic microstructure and large effective grain sizes. Continuous cooling transformation diagrams for five weld metal chemistries applicable to mechanized pulsed gas metal arc welding of modern high strength pipe steel (SMYS>550 MPa) have been constructed. Welds at heat inputs of 1.5 kJmm-1 and 0.5 kJmm-1 have been created for simulation and analysis. Dilatometric analysis was performed on weld metal specimens cut from single pass 1.5 kJmm-1 as deposited beads. The resulting microstructures were found to range from martensite to polygonal ferrite. There is excellent agreement between the simulated and as deposited weld metal regions. Toughness testing indicates improved energy absorption at -20

  12. HIGH VOLTAGE GENERATOR

    DOEpatents

    Schwemin, A.J.

    1959-03-17

    A generator is presented for producing relatively large currents at high voltages. In general, the invention comprises a plurality of capacitors connected in series by a plurality of switches alternately disposed with the capacitors. The circuit is mounted for movement with respect to contact members and switch closure means so that a load device and power supply are connected across successive numbers of capacitors, while the other capacitors are successively charged with the same power supply.

  13. High voltage generator

    DOEpatents

    Schwemin, A. J.

    1959-03-17

    A generator for producing relatively large currents at high voltages is described. In general, the invention comprises a plurality of capacitors connected in series by a plurality of switches alternately disposed with the capacitors. The above-noted circuit is mounted for movement with respect to contact members and switch closure means so that a load device and power supply are connected across successive numbers of capacitors, while the other capacitors are successively charged with the same power supply.

  14. Strength analysis of laser welded lap joint for ultra high strength steel

    NASA Astrophysics Data System (ADS)

    Jeong, Young Cheol; Kim, Cheol Hee; Cho, Young Tae; Jung, Yoon Gyo

    2013-12-01

    Several industries including the automotive industry have recently applied the process of welding high strength steel. High strength steel is steel that is harder than normal high strength steel, making it much stronger and stiffer. HSS can be formed in pieces that can be up to 10 to 15 percent thinner than normal steel without sacrificing strength, which enables weight reduction and improved fuel economy. Furthermore, HSS can be formed into complex shapes that can be welded into structural areas. This study is based on previous experiments and is aimed at establishing the stress distribution for laser welded high strength steel. Research on the stress distribution for laser welded high strength steel is conducted by using Solid Works, a program that analyzes the stress of a virtual model. In conclusion, we found that the stress distribution is changed depending on the shape of welded lap joint. In addition, the Influence of the stress distribution on welded high strength steel can be used to standard for high energy welding of high strength steel, and we can also predict the region in welded high strength steel that may cracked.

  15. High voltage pulse generator

    DOEpatents

    Fasching, George E.

    1977-03-08

    An improved high-voltage pulse generator has been provided which is especially useful in ultrasonic testing of rock core samples. An N number of capacitors are charged in parallel to V volts and at the proper instance are coupled in series to produce a high-voltage pulse of N times V volts. Rapid switching of the capacitors from the paralleled charging configuration to the series discharging configuration is accomplished by using silicon-controlled rectifiers which are chain self-triggered following the initial triggering of a first one of the rectifiers connected between the first and second of the plurality of charging capacitors. A timing and triggering circuit is provided to properly synchronize triggering pulses to the first SCR at a time when the charging voltage is not being applied to the parallel-connected charging capacitors. Alternate circuits are provided for controlling the application of the charging voltage from a charging circuit to be applied to the parallel capacitors which provides a selection of at least two different intervals in which the charging voltage is turned "off" to allow the SCR's connecting the capacitors in series to turn "off" before recharging begins. The high-voltage pulse-generating circuit including the N capacitors and corresponding SCR's which connect the capacitors in series when triggered "on" further includes diodes and series-connected inductors between the parallel-connected charging capacitors which allow sufficiently fast charging of the capacitors for a high pulse repetition rate and yet allow considerable control of the decay time of the high-voltage pulses from the pulse-generating circuit.

  16. Aluminum/steel wire composite plates exhibit high tensile strength

    NASA Technical Reports Server (NTRS)

    1966-01-01

    Composite plate of fine steel wires imbedded in an aluminum alloy matrix results in a lightweight material with high tensile strength. Plates have been prepared having the strength of titanium with only 85 percent of its density.

  17. Microstructure of high-strength foam concrete

    SciTech Connect

    Just, A.; Middendorf, B.

    2009-07-15

    Foam concretes are divided into two groups: on the one hand the physically foamed concrete is mixed in fast rotating pug mill mixers by using foaming agents. This concrete cures under atmospheric conditions. On the other hand the autoclaved aerated concrete is chemically foamed by adding aluminium powder. Afterwards it is cured in a saturated steam atmosphere. New alternatives for the application of foam concretes arise from the combination of chemical foaming and air curing in manufacturing processes. These foam concretes are new and innovative building materials with interesting properties: low mass density and high strength. Responsible for these properties are the macro-, meso- and microporosity. Macropores are created by adding aluminium powder in different volumes and with different particle size distributions. However, the microstructure of the cement matrix is affected by meso- and micropores. In addition, the matrix of the hardened cement paste can be optimized by the specific use of chemical additives for concrete. The influence of aluminium powder and chemical additives on the properties of the microstructure of the hardened cement matrices were investigated by using petrographic microscopy as well as scanning electron microscopy.

  18. Structural application of high strength, high temperature ceramics

    NASA Technical Reports Server (NTRS)

    Hall, W. B.

    1982-01-01

    The operation of rocket engine turbine pumps is limited by the temperature restrictions of metallic components used in the systems. Mechanical strength and stability of these metallic components decrease drastically at elevated temperatures. Ceramic materials that retain high strength at high temperatures appear to be a feasible alternate material for use in the hot end of the turbopumps. This project identified and defined the processing parameters that affected the properties of Si3N4, one of candidate ceramic materials. Apparatus was assembled and put into operation to hot press Si3N4 powders into bulk material for in house evaluation. A work statement was completed to seek outside contract services to design, manufacture, and evaluate Si3N4 components in the service environments that exists in SSME turbopumps.

  19. Gaseous hydrogen embrittlement of high strength steels

    NASA Technical Reports Server (NTRS)

    Gangloff, R. P.; Wei, R. P.

    1977-01-01

    The effects of temperature, hydrogen pressure, stress intensity, and yield strength on the kinetics of gaseous hydrogen assisted crack propagation in 18Ni maraging steels were investigated experimentally. It was found that crack growth rate as a function of stress intensity was characterized by an apparent threshold for crack growth, a stage where the growth rate increased sharply, and a stage where the growth rate was unchanged over a significant range of stress intensity. Cracking proceeded on load application with little or no detectable incubation period. Gaseous hydrogen embrittlement susceptibility increased with increasing yield strength.

  20. Development of K-Basin High-Strength Homogeneous Sludge Simulants and Correlations Between Unconfined Compressive Strength and Shear Strength

    SciTech Connect

    Onishi, Yasuo; Baer, Ellen BK; Chun, Jaehun; Yokuda, Satoru T.; Schmidt, Andrew J.; Sande, Susan; Buchmiller, William C.

    2011-02-20

    K-Basin sludge will be stored in the Sludge Transport and Storage Containers (STSCs) at an interim storage location on Central Plateau before being treated and packaged for disposal. During the storage period, sludge in the STSCs may consolidate/agglomerate, potentially resulting in high-shear-strength material. The Sludge Treatment Project (STP) plans to use water jets to retrieve K-Basin sludge after the interim storage. STP has identified shear strength to be a key parameter that should be bounded to verify the operability and performance of sludge retrieval systems. Determining the range of sludge shear strength is important to gain high confidence that a water-jet retrieval system can mobilize stored K-Basin sludge from the STSCs. The shear strength measurements will provide a basis for bounding sludge properties for mobilization and erosion. Thus, it is also important to develop potential simulants to investigate these phenomena. Long-term sludge storage tests conducted by Pacific Northwest National Laboratory (PNNL) show that high-uranium-content K-Basin sludge can self-cement and form a strong sludge with a bulk shear strength of up to 65 kPa. Some of this sludge has 'paste' and 'chunks' with shear strengths of approximately 3-5 kPa and 380-770 kPa, respectively. High-uranium-content sludge samples subjected to hydrothermal testing (e.g., 185 C, 10 hours) have been observed to form agglomerates with a shear strength up to 170 kPa. These high values were estimated by measured unconfined compressive strength (UCS) obtained with a pocket penetrometer. Due to its ease of use, it is anticipated that a pocket penetrometer will be used to acquire additional shear strength data from archived K-Basin sludge samples stored at the PNNL Radiochemical Processing Laboratory (RPL) hot cells. It is uncertain whether the pocket penetrometer provides accurate shear strength measurements of the material. To assess the bounding material strength and potential for erosion, it

  1. Silicon nitride having a high tensile strength

    DOEpatents

    Pujari, V.K.; Tracey, D.M.; Foley, M.R.; Paille, N.I.; Pelletier, P.J.; Sales, L.C.; Willkens, C.A.; Yeckley, R.L.

    1996-11-05

    A silicon nitride ceramic is disclosed comprising: (a) inclusions no greater than 25 microns in length, (b) agglomerates no greater than 20 microns in diameter, and (c) a surface finish of less than about 8 microinches, said ceramic having a four-point flexural strength of at least about 900 MPa. 4 figs.

  2. Silicon nitride having a high tensile strength

    DOEpatents

    Pujari, Vimal K.; Tracey, Dennis M.; Foley, Michael R.; Paille, Norman I.; Pelletier, Paul J.; Sales, Lenny C.; Willkens, Craig A.; Yeckley, Russell L.

    1996-01-01

    A silicon nitride ceramic comprising: a) inclusions no greater than 25 microns in length, b) agglomerates no greater than 20 microns in diameter, and c) a surface finish of less than about 8 microinches, said ceramic having a four-point flexural strength of at least about 900 MPa.

  3. Ultra-high-strength boron fibers

    NASA Technical Reports Server (NTRS)

    Behrendt, D. R.; Dicarlo, J. A.; Grimes, H. H.; Smith, R. J.

    1978-01-01

    Boron-on-tungsten fibers with tensile strength and strain-to-failure values increased by fifty percent over commercial grades are produced by controlled chemical-etching process. Improved fibers have potential applications as lightweight composites in ground vehicles, spacecraft, and rotors for energy storage.

  4. Physical processes at high field strengths

    SciTech Connect

    Rhodes, C.K.

    1986-01-01

    Measurements of the radiation produced by the high field interaction with the rare gases have revealed the presence of both copious harmonic production and fluorescence. The highest harmonic observed was the seventeenth (14.6 rm) in Ne, the shortest wavelength ever produced by that means. Strong fluorescence was seen in Ar, Kr, and Xe with the shortest wavelengths observed being below 10 nm. Furthermore, radiation from inner-shell excited configurations in Xe, specifically the 4d/sup 9/5s5p ..-->.. 4d/sup 10/5s manifold at approx. 17.7 nm, was detected. The behaviors of the rare gases with respect to multiquantum ionization, harmonic production, and fluorescence were found to be correlated so that the materials fell into two groups, He and Ne in one and Ar, Kr, and Xe in the other. These experimental findings, in alliance with other studies on inner-shell decay processes, give evidence for a role of atomic correlations in a direct nonlinear process of inner-shell excitation. It is expected that an understanding of these high-field processes will enable the generation of stimulated emission in the x-ray range. 59 refs., 6 figs., 5 tabs.

  5. High-temperature strength of sapphire

    NASA Astrophysics Data System (ADS)

    Harris, Daniel C.

    2000-10-01

    The Sapphire Statistical Characterization and Risk Reduction Program tested approximately 1500 4-point flexure bars with different crystal orientations at different temperatures to establish a mechanical strength database for engineering design. Sapphire coupons were selected to represent surfaces on two different missile windows and a missile dome. Sapphire was obtained from the same suppliers used for the windows or dome and, as much as possible, coupons were fabricated in the same manner as the corresponding part of the window or dome. Perhaps the most interesting result was that sapphire from one fabricator was 50% stronger than sapphire made to the same specifications from the same blanks by another fabricator. In laser heating tests, sapphire performed better than predicted from flexure tests. When a compliant layer of graphite was used as a pad between the test specimens and the load fixture, sapphire in which the principal axis of tension and compression was parallel to the c-axis increased in apparent strength by a factor of 2 - 3. Strengths of other crystal orientations were not significantly affected by the graphite pads, but the incidence of twinning at 883 K was reduced by graphite.

  6. Friction Stir Spot Welding of Advanced High Strength Steels

    SciTech Connect

    Hovanski, Yuri; Grant, Glenn J.; Santella, M. L.

    2009-11-13

    Friction stir spot welding techniques were developed to successfully join several advanced high strength steels. Two distinct tool materials were evaluated to determine the effect of tool materials on the process parameters and joint properties. Welds were characterized primarily via lap shear, microhardness, and optical microscopy. Friction stir spot welds were compared to the resistance spot welds in similar strength alloys by using the AWS standard for resistance spot welding high strength steels. As further comparison, a primitive cost comparison between the two joining processes was developed, which included an evaluation of the future cost prospects of friction stir spot welding in advanced high strength steels.

  7. HIGH EFFICIENCY SYNGAS GENERATION

    SciTech Connect

    Robert J. Copeland; Yevgenia Gershanovich; Brian Windecker

    2005-02-01

    This project investigated an efficient and low cost method of auto-thermally reforming natural gas to hydrogen and carbon monoxide. Reforming is the highest cost step in producing products such as methanol and Fisher Tropsch liquids (i.e., gas to liquids); and reducing the cost of reforming is the key to reducing the cost of these products. Steam reforming is expensive because of the high cost of the high nickel alloy reforming tubes (i.e., indirectly fired reforming tubes). Conventional auto-thermal or Partial Oxidation (POX) reforming minimizes the size and cost of the reformers and provides a near optimum mixture of CO and hydrogen. However POX requires pure oxygen, which consumes power and significantly increases the cost to reforming. Our high efficiency process extracts oxygen from low-pressure air with novel oxygen sorbent and transfers the oxygen to a nickel-catalyzed reformer. The syngas is generated at process pressure (typically 20 to 40 bar) without nitrogen dilution and has a 1CO to 2H{sub 2} ratio that is near optimum for the subsequent production of Fisher-Tropsch liquid to liquids and other chemicals (i.e., Gas to Liquids, GTL). Our high process efficiency comes from the way we transfer the oxygen into the reformer. All of the components of the process, except for the oxygen sorbent, are commonly used in commercial practice. A process based on a longlived, regenerable, oxygen transfer sorbent could substantially reduce the cost of natural gas reforming to syngas. Lower cost syngas (CO + 2H{sub 2}) that is the feedstock for GTL would reduce the cost of GTL and for other commercial applications (e.g., methanol, other organic chemicals). The vast gas resources of Alaska's North Slope (ANS) offer more than 22 Tcf of gas and GTL production in this application alone, and could account for as much as 300,000 to 700,000 bpd for 20 to 30+ years. We developed a new sorbent, which is an essential part of the High Efficiency Oxygen Process (HOP). We tested the

  8. Correlation between compressive strength and ultrasonic pulse velocity of high strength concrete incorporating chopped basalt fibre

    NASA Astrophysics Data System (ADS)

    Shafiq, Nasir; Fadhilnuruddin, Muhd; Elshekh, Ali Elheber Ahmed; Fathi, Ahmed

    2015-07-01

    Ultrasonic pulse velocity (UPV), is considered as the most important test for non-destructive techniques that are used to evaluate the mechanical characteristics of high strength concrete (HSC). The relationship between the compressive strength of HSC containing chopped basalt fibre stands (CBSF) and UPV was investigated. The concrete specimens were prepared using a different ratio of CBSF as internal strengthening materials. The compressive strength measurements were conducted at the sample ages of 3, 7, 28, 56 and 90 days; whilst, the ultrasonic pulse velocity was measured at 28 days. The result of HSC's compressive strength with the chopped basalt fibre did not show any improvement; instead, it was decreased. The UPV of the chopped basalt fibre reinforced concrete has been found to be less than that of the control mix for each addition ratio of the basalt fibre. A relationship plot is gained between the cube compressive strength for HSC and UPV with various amounts of chopped basalt fibres.

  9. Proceedings: 1986 Workshop on Advanced High-Strength Materials

    SciTech Connect

    1989-05-01

    Stress corrosion cracking (SCC) has contributed to many in-service failures of high-strength LWR components. In 25 workshop presentations, this report addresses the effects of metallurgical factors, manufacturing processes, design improvements, and installation practices on the resistance of high-strength alloys to SCC.

  10. Increasing Lean Mass and Strength: A Comparison of High Frequency Strength Training to Lower Frequency Strength Training

    PubMed Central

    THOMAS, MICHAEL H.; BURNS, STEVE P.

    2016-01-01

    The purpose of this study was to determine the effect strength training frequency has on improvements in lean mass and strength. Participants were 7 women and 12 men, age (χ̄= 34.64 years ± 6.91 years), with strength training experience, training age (χ̄= 51.16 months ± 39.02 months). Participants were assigned to one of two groups to equal baseline group demographics. High frequency training group (HFT) trained each muscle group as the agonist, 3 times per week, exercising with 3 sets per muscle group per session (3 total body workouts). Low frequency training group (LFT) trained each muscle group as the agonist one time per week, completing all 9 sets during that one workout. LFT consisted of a routine split over three days: 1) pectoralis, deltoids, and triceps; 2) upper back and biceps; 3) quadriceps, hamstrings, calves, and abdominals. Following eight weeks of training, HFT increased lean mass by 1.06 kg ± 1.78 kg, (1.9%), and LFT increased lean mass by .99 kg ± 1.31 kg, (2.0%). HFT strength improvements on the chest press was 9.07 kg ± 6.33 kg, (11%), and hack squat 20.16 kg ± 11.59 kg, (21%). LFT strength improvements on chest press was 5.80kg ± 4.26 kg, (7.0%), and hack squat 21.83 kg ± 11.17 kg, (24 %). No mean differences between groups were significant. These results suggest that HFT and LFT of equal set totals result in similar improvements in lean mass and strength, following 8 weeks of strength training. PMID:27182422

  11. High Strength Stainless Steel Properties that Affect Resistance Welding

    SciTech Connect

    Kanne, W.R.

    2001-08-01

    This report discusses results of a study on selected high strength stainless steel alloy properties that affect resistance welding. The austenitic alloys A-286, JBK-75 (Modified A-286), 21-6-9, 22-13-5, 316 and 304L were investigated and compared. The former two are age hardenable, and the latter four obtain their strength through work hardening. Properties investigated include corrosion and its relationship to chemical cleaning, the effects of heat treatment on strength and surface condition, and the effect of mechanical properties on strength and weldability.

  12. High-strength silicon carbides by hot isostatic pressing

    NASA Technical Reports Server (NTRS)

    Dutta, Sunil

    1988-01-01

    Silicon carbide has strong potential for heat engine hardware and other high-temperature applications because of its low density, good strength, high oxidation resistance, and good high-temperature creep resistance. Hot isostatic pressing (HIP) was used for producing alpha and beta silicon carbide (SiC) bodies with near-theoretical density, ultrafine grain size, and high strength at processing temperatures of 1900 to 2000 C. The HIPed materials exhibited ultrafine grain size. Furthermore, no phase transformation from beta to alpha was observed in HIPed beta-SiC. Both materials exhibited very high average flexural strength. It was also shown that alpha-SiC bodies without any sintering aids, when HIPed to high final density, can exhibit very high strength. Fracture toughness K (sub C) values were determined to be 3.6 to 4.0 MPa m (sup 1/2) for HIPed alpha-SiC and 3.7 to 4.1 MPa m (sup 1/2) for HIPed beta-SiC. In the HIPed specimens strength-controlling flaws were typically surface related. In spite of improvements in material properties such as strength and fracture toughness by elimination of the larger strength-limiting flaws and by grain size refinement, HIPing has no effect on the Weibull modulus.

  13. High-strength silicon carbides by hot isostatic pressing

    NASA Technical Reports Server (NTRS)

    Dutta, Sunil

    1989-01-01

    Silicon carbide has strong potential for heat engine hardware and other high-temperature applications because of its low density, good strength, high oxidation resistance, and good high-temperature creep resistance. Hot isostatic pressing (HIP) was used for producing alpha and beta silicon carbide (SiC) bodies with near-theoretical density, ultrafine grain size, and high strength at processing temperatures of 1900 to 2000 C. The HIPed materials exhibited ultrafine grain size. Furthermore, no phase transformation from beta to alpha was observed in HIPed beta-SiC. Both materials exhibited very high average flexural strength. It was also shown that alpha-SiC bodies without any sintering aids, when HIPed to high final density, can exhibit very high strength. Fracture toughness K (sub C) values were determined to be 3.6 to 4.0 MPa m (sup 1/2) for HIPed alpha-SiC and 3.7 to 4.1 MPa m (sup 1/2) for HIPed beta-SiC. In the HIPed specimens strength-controlling flaws were typically surface related. In spite of improvements in material properties such as strength and fracture toughness by elimination of the larger strength-limiting flaws and by grain size refinement, HIPing has no effect on the Weibull modulus.

  14. The High School Strength and Conditioning Professional: A Job Description.

    ERIC Educational Resources Information Center

    Best, Randy

    2001-01-01

    Presents a job description for the high school strength and conditioning professional, who is in a unique position to integrate athletics and academics, highlighting: minimum qualifications; school-related benefits derived from employing a strength and conditioning professional; whom the professional reports to and works with; job…

  15. Highly stable aerosol generator

    DOEpatents

    DeFord, H.S.; Clark, M.L.

    1981-11-03

    An improved compressed air nebulizer has been developed such that a uniform aerosol particle size and concentration may be produced over long time periods. This result is achieved by applying a vacuum pressure to the makeup assembly and by use of a vent tube between the atmosphere and the makeup solution. By applying appropriate vacuum pressures to the makeup solution container and by proper positioning of the vent tube, a constant level of aspirating solution may be maintained within the aspirating assembly with aspirating solution continuously replaced from the makeup solution supply. This device may also be adapted to have a plurality of aerosol generators and only one central makeup assembly. 2 figs.

  16. Highly stable aerosol generator

    DOEpatents

    DeFord, Henry S.; Clark, Mark L.

    1981-01-01

    An improved compressed air nebulizer has been developed such that a uniform aerosol particle size and concentration may be produced over long time periods. This result is achieved by applying a vacuum pressure to the makeup assembly and by use of a vent tube between the atmosphere and the makeup solution. By applying appropriate vacuum pressures to the makeup solution container and by proper positioning of the vent tube, a constant level of aspirating solution may be maintained within the aspirating assembly with aspirating solution continuously replaced from the makeup solution supply. This device may also be adapted to have a plurality of aerosol generators and only one central makeup assembly.

  17. Investigation of the plastic fracture of high strength steels

    NASA Technical Reports Server (NTRS)

    Cox, T. B.; Low, J. R., Jr.

    1972-01-01

    This investigation deals in detail with the three recognized stages of plastic fracture in high strength steels, namely, void initiation, void growth, and void coalescence. The particular steels under investigation include plates from both commercial purity and high purity heats of AISI 4340 and 18 Ni, 200 grade maraging steels. A scanning electron microscope equipped with an X-ray energy dispersive analyzer, together with observations made using light microscopy, revealed methods of improving the resistance of high strength steels to plastic fracture.

  18. BIOLOGICAL TREATMENT OF HIGH STRENGTH PETROCHEMICAL WASTEWATER

    EPA Science Inventory

    The biological treatment of a complex petrochemical wastewater containing high concentrations of organic chlorides, nitrates, and amines was initially studied using a sequence of anaerobic methanogenesis and oxygen activated sludge. Bench-scale and pilot-plant treatability studie...

  19. High strength forgeable tantalum base alloy

    NASA Technical Reports Server (NTRS)

    Buckman, R. W., Jr.

    1975-01-01

    Increasing tungsten content of tantalum base alloy to 12-15% level will improve high temperature creep properties of existing tantalum base alloys while retaining their excellent fabrication and welding characteristics.

  20. Retention of ductility in high-strength steels

    NASA Technical Reports Server (NTRS)

    Parker, E. R.; Zackay, V. F.

    1969-01-01

    To produce high strength alloy steel with retention of ductility, include tempering, cooling and subsequent tempering. Five parameters for optimum results are pretempering temperature, amount of strain, strain rate, temperature during strain, and retempering temperature.

  1. Investigation of the plastic fracture of high strength steels

    NASA Technical Reports Server (NTRS)

    Cox, T. B.; Low, J. R., Jr.

    1972-01-01

    An investigation of the plastic fracture process to improve tensile strength in high strength steels is presented. Two generic types of steels are considered: a quenched and tempered grade and a maraging grade, in order to compare two different matrix microstructures. Each type of steel was studied in commercial grade purity and in special melted high purity form, low in residual and impurity elements. The specific alloys dealt with include AISI 4340 and 18 Ni, 200 grade maraging steel, both heat treated to the same yield strength level of approximately 200 ksi.

  2. Survey of Processing Methods for High Strength High Conductivity Wires for High Field Magnet Applications

    SciTech Connect

    Han, K.; Embury, J.D.

    1998-10-01

    This paper will deal with the basic concepts of attaining combination of high strength and high conductivity in pure materials, in-situ composites and macrocomposites. It will survey current attainments, and outline where some future developments may lie in developing wire products that are close to the theoretical strength of future magnet applications.

  3. Application of high strength grooved wire in fiber protection

    NASA Astrophysics Data System (ADS)

    Kamata, Y.; Niijima, M.; Kawazoe, H.; Ogai, M.; Ninomiya, T.

    1986-11-01

    V Grooves were successfully machined on the high strength steel wire of around 3 mm diameter. Eight of thin coated fibers were protected in these grooves against pulling force of greater than 150kg (allowing 0.2% strain) and lateral pressure of greater 400kg/5cm. Many applications of this high strength grooved wire can be expected in design of optical fiber cable.

  4. Stress corrosion of high strength aluminum alloys.

    NASA Technical Reports Server (NTRS)

    Cocks, F. H.; Brummer, S. B.

    1972-01-01

    An investigation has been carried out to examine the relationship of the observed chemical and mechanical properties of Al-Cu and Al-Zn-Mg alloys to the stress corrosion mechanisms which dominate in each case. Two high purity alloys and analogous commercial alloys were selected. Fundamental differences between the behavior of Al-Cu and of Al-Zn-Mg alloys were observed. These differences in the corrosion behavior of the two types of alloys are augmented by substantial differences in their mechanical behavior. The relative cleavage energy of the grain boundaries is of particular importance.

  5. High power microwave generator

    SciTech Connect

    Minich, Roger W.

    1988-01-01

    A device (10) for producing high-powered and coherent microwaves is described. The device comprises an evacuated, cylindrical, and hollow real cathode (20) that is driven to inwardly field emit relativistic electrons. The electrons pass through an internally disposed cylindrical and substantially electron-transparent cylindrical anode (24), proceed toward a cylindrical electron collector electrode (26), and form a cylindrical virtual cathode (32). Microwaves are produced by spatial and temporal oscillations of the cylindrical virtual cathode (32), and by electrons that reflex back and forth between the cylindrical virtual cathode (32) and the cylindrical real cathode (20).

  6. Investigation of ultra violet (UV) resistance for high strength fibers

    NASA Astrophysics Data System (ADS)

    Said, M. A.; Dingwall, Brenda; Gupta, A.; Seyam, A. M.; Mock, G.; Theyson, T.

    Ultra long duration balloons (ULDB), currently under development by the National Aeronautics and Space Administration (NASA), requires the use of high strength fibers in the selected super-pressure pumpkin design. The pumpkin shape balloon concept allows clear separation of the load transferring functions of the major structural elements of the pneumatic envelope, the tendons and the film. Essentially, the film provides the gas barrier and transfers only local pressure load to the tendons. The tendons, in the mean time, provide the global pressure containing strength. In that manner, the strength requirement for the film only depends on local parameters. The tendon is made of p-phenylene-2,6-benzobisoxazole (PBO) fibers, which is selected due to its high strength to weight ratio when compared to other high performance, commercially available, fibers. High strength fibers, however, are known to degrade upon exposure to light, particularly at short wavelengths. This paper reports the results of an investigation of the resistance of four commercial high strength fibers to ultra violet (UV) exposure. The results indicate that exposing high strength fibers in continuous yarn form to UV led to serious loss in strength of the fibers except for Spectra® fibers. The adverse changes in mechanical behavior occurred over short duration of exposure compared to the 100 day duration targeted for these missions. UV blocking finishes to improve the UV resistance of these fibers are being investigated. The application of these specially formulated coatings is expected to lead to significant improvement of the UV resistance of these high performance fibers. In this publication, we report on the mechanical behavior of the fibers pre- and post-exposure to UV, but without application of the blocking finishes.

  7. HIGH VOLTAGE GENERATOR

    DOEpatents

    Zito, G.V.

    1959-04-21

    This patent relates to high voltage supply circuits adapted for providing operating voltages for GeigerMueller counter tubes, and is especially directed to an arrangement for maintaining uniform voltage under changing conditions of operation. In the usual power supply arrangement for counter tubes the counter voltage is taken from across the power supply output capacitor. If the count rate exceeds the current delivering capaciiy of the capacitor, the capacitor voltage will drop, decreasing the counter voltage. The present invention provides a multivibrator which has its output voltage controlled by a signal proportional to the counting rate. As the counting rate increases beyond the current delivering capacity of the capacitor, the rectified voltage output from the multivibrator is increased to maintain uniform counter voltage.

  8. Shock properties of high-strength ceramics

    SciTech Connect

    Grady, D.E.

    1994-12-31

    A broad class of brittle solids subjected to large amplitude shock waves can support substantial shear stress (of order 2-10 GPa) without failing due to the very limited slip systems in these materials. When failure occurs under sufficiently intense shock loading, the effect is usually observed as a wave splitting in the compressive shock front. Because of the high confining stress state associated with the failure event in the shock compression environment, it is no longer certain whether the microstructural processes of deformation are brittle or ductile. Some, although by no means sufficient, evidence supports a brittle deformation mechanism in the materials of interest. The present short paper focuses on two aspects of the transition regime neighboring the HEL in the compressive shock process. First, issues of rate dependence associated with prompt yield under shock compression are not well understood. We report here on observations of wave profile data on ceramics, examining he issue of elastic precursor decay. Also in this study, a number of the experimental observations of failure waves in ceramic materials (principally glass) are surveyed. Some of the principal results are summarized and dynamic failure mechanisms consistent with these results are discussed.

  9. Fatigue Properties of Automobile High-Strength Bolts

    NASA Astrophysics Data System (ADS)

    Zhou, Congling; Nishida, Shin-Ichi; Hattori, Nobusuke

    This study is focused on the fatigue properties of automobile high-strength bolts, including the effect of mean stress level, pre-processing schedule and the residual stresses. And the mean stress levels are 0.3, 0.5 and 0.7 times to the tensile strength (σB) of the material respectively. The main results obtained are as follows: 1) the fatigue strength increases under the mean stress loading, but the differences between the loading levels are not so evident; 2) most of the cases in this study are broken from the bottom of the screw thread, and the crack initiated from the impurities.

  10. Microchip Electrophoresis at Elevated Temperatures and High Separation Field Strengths

    PubMed Central

    Mitra, Indranil; Marczak, Steven P.; Jacobson, Stephen C.

    2014-01-01

    We report free-solution microchip electrophoresis performed at elevated temperatures and high separation field strengths. We used microfluidic devices with 11-cm long separation channels to conduct separations at temperatures between 22 (ambient) and 45 °C and field strengths from 100 to 1000 V/cm. To evaluate separation performance, N-glycans were used as a model system and labeled with 8-aminopyrene-1,3,6-trisulfonic acid to impart charge for electrophoresis and render them fluorescent. Typically, increased diffusivity at higher temperatures leads to increased axial dispersion and poor separation performance; however, we demonstrate that sufficiently high separation field strengths can be used to offset the impact of increased diffusivity in order to maintain separation efficiency. Efficiencies for these free-solution separations are the same at temperatures of 25, 35, and 45 °C with separation field strengths ≥500 V/cm. PMID:24114979

  11. High strength nickel-chromium-iron austenitic alloy

    DOEpatents

    Gibson, Robert C.; Korenko, Michael K.

    1980-01-01

    A solid solution strengthened Ni-Cr-Fe alloy capable of retaining its strength at high temperatures and consisting essentially of 42 to 48% nickel, 11 to 13% chromium, 2.6 to 3.4% niobium, 0.2 to 1.2% silicon, 0.5 to 1.5% vanadium, 2.6 to 3.4% molybdenum, 0.1 to 0.3% aluminum, 0.1 to 0.3% titanium, 0.02 to 0.05% carbon, 0.002 to 0.015% boron, up to 0.06 zirconium, and the balance iron. After solution annealing at 1038.degree. C. for one hour, the alloy, when heated to a temperature of 650.degree. C., has a 2% yield strength of 307 MPa, an ultimate tensile strength of 513 MPa and a rupture strength of as high as 400 MPa after 100 hours.

  12. High Strength and Thermally Stable Nanostructured Magnesium Alloys and Nanocomposites

    NASA Astrophysics Data System (ADS)

    Chang, Yuan-Wei

    Magnesium and its alloys are currently in the spotlight of global research because of the need to limit energy consumption and reduce the environmental impact. In particular, their low densities compared to other structural metals make them a very attractive alternative in the automobile and aerospace industries. However, their low strength compared to other structural materials (e.g. Al and steels) has limited their widespread application. This dissertation presents the results of developing and investigation of a high strength nanostructured magnesium-aluminum alloy and composite. The nanostructured magnesium alloy is prepared by cryomilling and consolidated by spark-plasma-sintering. Focused ion beam is used to prepare micropillars with different diameters ranging from 1.5 to 8 mum and micro-compression test is conducted by nanoindenter in order to evaluate the mechanical properties. The yield strength obtained in the present study is around three times higher than conventional magnesium alloys (120 MPa vs. 370 MPa). The yield strength of the nanostructured magnesium alloy is further improved through hot extrusion, resulting in a yield strength of 550 MPa and an ultimate strength of 580 MPa. The nanostructured magnesium alloy exhibits a strong size-dependence, and a significant improvement in strength is observed when the pillar diameter is reduced to below 3.5 mum. The deformation mechanisms of the compressed pillars were characterized using transmission electron microscopy. The size-induced strengthening is attributed to a less number of dislocation sources along with a higher activity of non-basal deformation mechanisms. We have also developed a high strength and thermally stable nanostructured magnesium composite by adding diamantane. A yield strength of 500 MPa is achieved, moreover, excellent thermal stability is demonstrated in the magnesium alloy containing diamantanes. The strength and grain size are thermally stable after annealing at 400°C for 100

  13. A universal fracture criterion for high-strength materials

    PubMed Central

    Qu, Rui Tao; Zhang, Zhe Feng

    2013-01-01

    Recently developed advanced high-strength materials like metallic glasses, nanocrystalline metallic materials, and advanced ceramics usually fracture in a catastrophic brittle manner, which makes it quite essential to find a reasonable fracture criterion to predict their brittle failure behaviors. Based on the analysis of substantial experimental observations of fracture behaviors of metallic glasses and other high-strength materials, here we developed a new fracture criterion and proved it effective in predicting the critical fracture conditions under complex stress states. The new criterion is not only a unified one which unifies the three classical failure criteria, i.e., the maximum normal stress criterion, the Tresca criterion and the Mohr-Coulomb criterion, but also a universal criterion which has the ability to describe the fracture mechanisms of a variety of different high-strength materials under various external loading conditions.

  14. Anomolous Fatigue Crack Growth Phenomena in High-Strength Steel

    NASA Technical Reports Server (NTRS)

    Forth, Scott C.; James, Mark A.; Johnston, William M., Jr.; Newman, James C., Jr.

    2004-01-01

    The growth of a fatigue crack through a material is the result of a complex interaction between the applied loading, component geometry, three-dimensional constraint, load history, environment, material microstructure and several other factors. Previous studies have developed experimental and computational methods to relate the fatigue crack growth rate to many of the above conditions, with the intent of discovering some fundamental material response, i.e. crack growth rate as a function of something. Currently, the technical community uses the stress intensity factor solution as a simplistic means to relate fatigue crack growth rate to loading, geometry and all other variables. The stress intensity factor solution is a very simple linear-elastic representation of the continuum mechanics portion of crack growth. In this paper, the authors present fatigue crack growth rate data for two different high strength steel alloys generated using standard methods. The steels exhibit behaviour that appears unexplainable, compared to an aluminium alloy presented as a baseline for comparison, using the stress intensity factor solution.

  15. Experimental oscillator strengths of highly excited levels of Mo II

    NASA Astrophysics Data System (ADS)

    Aragón, C.; Aguilera, J. A.; Ortiz, M.; Mayo-García, R.

    2016-05-01

    Measurements of 161 oscillator strengths arising from highly excited levels of Mo II are presented, 148 of which are obtained for the first time. These results extend the previous ones already published on lower excited levels of Mo II. A laser-induced plasma generated from a fused glass sample prepared from molybdenum oxide with a Mo atomic concentration of 0.1% was used to obtain the presented radiative parameters via laser-induced breakdown spectroscopy. Measurements were carried out with an electron density of (2.5 ± 0.1) · 1017 cm‑3 and an electron temperature of 14 400 ± 200 K as the plasma evolved in air at atmospheric pressure. As a consequence, an optically thin plasma and a local thermodynamic equilibrium environment were then present in the measurements. In order to put on an absolute scale the relative intensities, both the combination of branching fractions with measured lifetimes and the comparison of well-known lines using the plasma temperature were carried out. Also, the new results are compared with previously theoretical and obtained experimental values wherever possible.

  16. Optimum high temperature strength of two-dimensional nanocomposites

    SciTech Connect

    Monclús, M. A.; Molina-Aldareguía, J. M.; Polcar, T.; Llorca, J.

    2013-11-01

    High-temperature nanoindentation was used to reveal nano-layer size effects on the hardness of two-dimensional metallic nanocomposites. We report the existence of a critical layer thickness at which strength achieves optimal thermal stability. Transmission electron microscopy and theoretical bicrystal calculations show that this optimum arises due to a transition from thermally activated glide within the layers to dislocation transmission across the layers. We demonstrate experimentally that the atomic-scale properties of the interfaces profoundly affect this critical transition. The strong implications are that interfaces can be tuned to achieve an optimum in high temperature strength in layered nanocomposite structures.

  17. Shock characterization of an ultra-high strength concrete

    NASA Astrophysics Data System (ADS)

    Erzar, B.; Pontiroli, C.; Buzaud, E.

    2016-05-01

    Nowadays, the design of protective structures may imply ultra-high performance concretes. These materials present a compressive strength 5 times higher than standard concretes. However, few reliable data on the shock response of such materials are available in the literature. Thus, a characterization of an ultra-high strength concrete has been conducted by means of hydrostatic and triaxial tests in the quasi-static regime, and plate impact experiments for shock response. Data have been gathered up to 6 GPa and a simple modelling approach has been applied to get a reliable representation of the shock compression of this concrete.

  18. Calibration of the high-pressure cohesive strength meter (CSM)

    NASA Astrophysics Data System (ADS)

    Vardy, S.; Saunders, J. E.; Tolhurst, T. J.; Davies, P. A.; Paterson, D. M.

    2007-05-01

    Coastal erosion is an immense economic and social problem that has been receiving increased attention in recent years. A number of devices have been developed to determine the sediment stability in coastal areas: laboratory and field flumes; a range of different erosion devices; shear vanes and fall cone penetrometers. The cohesive strength meter (CSM) erosion device was developed to determine in situ the temporal and spatial variations in the erosion threshold of muddy intertidal sediments. Technological developments have enabled considerable improvements to be made to the original design over the last 15 years. This paper describes modifications to the CSM system that extend the range of eroding pressures the device can generate, to enable measurements to be made on very stable and consolidated sediments such as saltmarshes. A recalibration of the modified device found inconsistencies in the calibration for CSM devices presently in use, therefore a completely new calibration method is presented. This calibrates the CSM jet pressure to the pressure on the surface sediment (henceforth termed the "stagnation pressure"). The stagnation pressure when erosion is detected is assumed to be a relative (but not absolute) measure of the erosion threshold. The application of the device using the new calibration under laboratory conditions on muddy sediment is also presented. The following calibration equations were generated for the individual CSM models, where y=stagnation pressure at the sediment surface (N m -2) and x=jet exit pressure (kPa): Mark IV (high pressure): y=22.652 x; Mark IV (prototype): y=8.528 x; and Mark III: y=15.844 x.

  19. Cytocompatibility of high strength non-oxide ceramics.

    PubMed

    Cappi, Benjamin; Neuss, Sabine; Salber, Jochen; Telle, Rainer; Knüchel, Ruth; Fischer, Horst

    2010-04-01

    Oxide ceramic materials like alumina (Al(2)O(3)) and zirconia (ZrO(2)) are frequently used for medical applications like implants and prostheses because of their excellent biocompatibility and high wear resistance. Unfortunately, oxide ceramics cannot be used for minimal invasive thin-walled implants like resurfacing hip prostheses because of their limited strength. The hypothesis of this study is that non-oxide ceramics like silicon nitride (Si(3)N(4)) and silicon carbide (SiC)-not previously used in the medical field-are not only high strength and mechanically reliable ceramic materials due to their high amount of covalent bonds, but also exhibit a suitable biocompatibility for use as medical implants and prostheses. Mechanical investigations and cell culture tests with mouse fibroblast cells (L929) and human mesenchymal stem cells (hMSC) were performed on the ceramics. An excellent cytocompatibility was demonstrated by live/dead stainings for both L929 cells and hMSC. HMSC were able to differentiate towards osteoblasts on all tested ceramics. The determined strength of silicon nitride and silicon carbide was shown as significantly higher than that of oxide ceramics. Our results indicate that the high strength non-oxide ceramics are material candidates in the future especially for highly loaded, thin-walled implants like ceramic resurfacing hip prostheses. PMID:19484770

  20. Uncertainties in obtaining high reliability from stress-strength models

    NASA Technical Reports Server (NTRS)

    Neal, Donald M.; Matthews, William T.; Vangel, Mark G.

    1992-01-01

    There has been a recent interest in determining high statistical reliability in risk assessment of aircraft components. The potential consequences are identified of incorrectly assuming a particular statistical distribution for stress or strength data used in obtaining the high reliability values. The computation of the reliability is defined as the probability of the strength being greater than the stress over the range of stress values. This method is often referred to as the stress-strength model. A sensitivity analysis was performed involving a comparison of reliability results in order to evaluate the effects of assuming specific statistical distributions. Both known population distributions, and those that differed slightly from the known, were considered. Results showed substantial differences in reliability estimates even for almost nondetectable differences in the assumed distributions. These differences represent a potential problem in using the stress-strength model for high reliability computations, since in practice it is impossible to ever know the exact (population) distribution. An alternative reliability computation procedure is examined involving determination of a lower bound on the reliability values using extreme value distributions. This procedure reduces the possibility of obtaining nonconservative reliability estimates. Results indicated the method can provide conservative bounds when computing high reliability. An alternative reliability computation procedure is examined involving determination of a lower bound on the reliability values using extreme value distributions. This procedure reduces the possibility of obtaining nonconservative reliability estimates. Results indicated the method can provide conservative bounds when computing high reliability.

  1. Strength Development of High-Strength Ductile Concrete Incorporating Metakaolin and PVA Fibers

    PubMed Central

    Nuruddin, Muhammad Fadhil; Shafiq, Nasir

    2014-01-01

    The mechanical properties of high-strength ductile concrete (HSDC) have been investigated using Metakaolin (MK) as the cement replacing material and PVA fibers. Total twenty-seven (27) mixes of concrete have been examined with varying content of MK and PVA fibers. It has been found that the coarser type PVA fibers provide strengths competitive to control or higher than control. Concrete with coarser type PVA fibers has also refined microstructure, but the microstructure has been undergone with the increase in aspect ratio of fibers. The microstructure of concrete with MK has also more refined and packing of material is much better with MK. PVA fibers not only give higher stiffness but also showed the deflection hardening response. Toughness Index of HSDC reflects the improvement in flexural toughness over the plain concrete and the maximum toughness indices have been observed with 10% MK and 2% volume fraction of PVA fibers. PMID:24707202

  2. Strength development of high-strength ductile concrete incorporating Metakaolin and PVA fibers.

    PubMed

    Nuruddin, Muhammad Fadhil; Khan, Sadaqat Ullah; Shafiq, Nasir; Ayub, Tehmina

    2014-01-01

    The mechanical properties of high-strength ductile concrete (HSDC) have been investigated using Metakaolin (MK) as the cement replacing material and PVA fibers. Total twenty-seven (27) mixes of concrete have been examined with varying content of MK and PVA fibers. It has been found that the coarser type PVA fibers provide strengths competitive to control or higher than control. Concrete with coarser type PVA fibers has also refined microstructure, but the microstructure has been undergone with the increase in aspect ratio of fibers. The microstructure of concrete with MK has also more refined and packing of material is much better with MK. PVA fibers not only give higher stiffness but also showed the deflection hardening response. Toughness Index of HSDC reflects the improvement in flexural toughness over the plain concrete and the maximum toughness indices have been observed with 10% MK and 2% volume fraction of PVA fibers. PMID:24707202

  3. TREATMENT OF HIGH STRENGTH MEATPACKING PLANT WASTEWATER BY LAND APPLICATION

    EPA Science Inventory

    The purpose of this study was to determine the treatability of high strength meatpacking plant wastewater by land application. Both infiltration and overland flow type systems were studied at various hydraulic and organic loading rates. In addition to characterization of the raw ...

  4. Fabrication of carbon film composites for high-strength structures

    NASA Technical Reports Server (NTRS)

    Preiswerk, P. R.; Lippman, M.

    1972-01-01

    Physical and mechanical properties of fiber composite materials consisting of carbon films are described. Application of carbon film structural composites for constructing microwave filters or optical instruments is proposed. Applications in aerospace and architectural structures for high strength and low density properties are discussed.

  5. High-strength porous carbon and its multifunctional applications

    SciTech Connect

    Wojtowicz, Marek A; Rubenstein, Eric P; Serio, Michael A; Cosgrove, Joseph E

    2013-12-31

    High-strength porous carbon and a method of its manufacture are described for multifunctional applications, such as ballistic protection, structural components, ultracapacitor electrodes, gas storage, and radiation shielding. The carbon is produced from a polymer precursor via carbonization, and optionally by surface activation and post-treatment.

  6. Friction Stir Spot Welding of Advanced High Strength Steels

    SciTech Connect

    Santella, Michael L; Hovanski, Yuri; Grant, Glenn J; Frederick, D Alan; Dahl, Michael E

    2009-02-01

    Friction stir spot welding was used to join two advanced high-strength steels using polycrystalline cubic boron nitride tooling. Numerous tool designs were employed to study the influence of tool geometry on weld joints produced in both DP780 and a hot-stamp boron steel. Tool designs included conventional, concave shouldered pin tools with several pin configurations; a number of shoulderless designs; and a convex, scrolled shoulder tool. Weld quality was assessed based on lap shear strength, microstructure, microhardness, and bonded area. Mechanical properties were functionally related to bonded area and joint microstructure, demonstrating the necessity to characterize processing windows based on tool geometry.

  7. Friction Stir Spot Welding of Advanced High Strength Steels

    SciTech Connect

    Hovanski, Yuri; Santella, M. L.; Grant, Glenn J.

    2009-12-28

    Friction stir spot welding was used to join two advanced high-strength steels using polycrystalline cubic boron nitride tooling. Numerous tool designs were employed to study the influence of tool geometry on weld joints produced in both DP780 and a hot-stamp boron steel. Tool designs included conventional, concave shouldered pin tools with several pin configurations; a number of shoulderless designs; and a convex, scrolled shoulder tool. Weld quality was assessed based on lap shear strength, microstructure, microhardness, and bonded area. Mechanical properties were functionally related to bonded area and joint microstructure, demonstrating the necessity to characterize processing windows based on tool geometry.

  8. High strength graphite and method for preparing same

    DOEpatents

    Overholser, Lyle G.; Masters, David R.; Napier, John M.

    1976-01-01

    High strength graphite is manufactured from a mixture of a particulate filler prepared by treating a particulate carbon precursor at a temperature in the range of about 400.degree. to 1000.degree. C., an organic carbonizable binder, and green carbonizable fibers in a concentration of not more than 2 weight per cent of the filler. The use of the relatively small quantity of green fibers provides a substantial increase in the flexural strength of the graphite with only a relatively negligible increase in the modulus of elasticity.

  9. Bond Strength of 5th, 6th and 7th Generation Bonding Agents to Intracanal Dentin of Primary Teeth

    PubMed Central

    Afshar, Hossein; Baradaran Nakhjavani, Yahya; Rahro Taban, Sedighe; Baniameri, Zahra; Nahvi, Azam

    2015-01-01

    Objectives: This in-vitro study sought to assess the push-out bond strength of a total etch and 2 self-etch bonding systems to intracanal dentin of primary anterior teeth (PAT). Materials and Methods: Thirty-six primary anterior teeth were randomly divided into 3 groups of 5th generation (Single Bond 2), 6th generation (Clearfil SE) and 7th generation (Single Bond Universal) bonding agents. The canal orifice was restored with composite resin and the push-out test was carried out to assess the bond strength. After applying the push-out load, specimens were evaluated under a light microscope at 40X magnification. One-way ANOVA and log-rank test on Kaplan-Meier curves were applied for the comparison of bond strength among the 3 groups. Results: The mean± standard deviation (SD) bond strength was 13.6±5.33 MPa for Single Bond 2, 13.85±5.86 MPa for Clearfil SE and 12.28±5.24 MPa for Single Bond Universal. The differences in bond strength among the 3 groups were not statistically significant (P>0.05). Conclusion: All three bonding agents are recommended for use with composite posts in PAT. However, due to high technical sensitivity of the Total Etch system, single or two-step self etch systems may be preferred for uncooperative children. PMID:26056518

  10. Fabrication Routes for High Strength High Conductivity Wires

    SciTech Connect

    Han, K.; Embury, J.D.; Sims, J.R.; Pantsyrnyi, V.I.; Shikov, A.; Bochvar, A.A.

    1998-10-01

    The development of suitable wires for magnet windings requires both the attainment of suitable combinations of properties (electrical conductivity and strength), the development of a production route capable of fabricating suitable quantity of wire of required dimension (5.2x7.6mm{sup 2} cross-section and 120 m in length) and a product with acceptable fabricability, joinability and service life. In this survey, the authors consider methods of producing suitable wire products by the codeformation of in-situ composites. This will include details of the quality control of the processing of Cu-Ag and Cu-Nb and the assessment of their detailed mechanical properties.

  11. Ultra-high Burst Strength of CVD Graphene Membranes

    NASA Astrophysics Data System (ADS)

    Wang, Luda; Boutilier, Michael; Kidambi, Piran; Karnik, Rohit; Microfluidics; Nanofluidics Research Lab Team

    2015-11-01

    Porous graphene membranes have significant potential in gas separation, water desalination and nanofiltration. Understanding the mechanical strength of porous graphene is crucial because membrane separations can involve high pressures. We studied the burst strength of CVD graphene membrane placed on porous support at applied pressures up to 100 bar by monitoring the gas flow rate across the membrane as a function of pressure. Increase of gas flow rate with pressure allowed for extraction of the burst fraction of graphene as it failed under increasing pressure. We also studied the effect of sub-nanometer pores on the ability of graphene to withstand pressure. The results showed that porous graphene membranes can withstand pressures comparable to or even higher than the >50 bar pressures encountered in water desalination, with non-porous CVD graphene exhibiting even higher mechanical strength. Our study shows that porous polycrystalline CVD graphene has ultra-high burst strength under applied pressure, suggesting the possibility for its use in high-pressure membrane separations. Principal Investigator

  12. High strength zirconia ceramics from green body preforms

    SciTech Connect

    Bate, L.D.; Grievson, B.; HAll, R.G.; Jones, A.G.

    1995-09-01

    High strength zirconia ceramic articles ({approx}1.3GPa) have been manufactured by subjecting a mixture of zirconia powder, a binder, a plasticiser and a solvent to high shear mixing to reduce the size of flaw forming powder agglomerates. A flexible green body preform was produced that was further extruded or calendered to the final shape, e.g. flat plates and coil springs, prior to sintering to full density.

  13. NEW HIGH STRENGTH AND FASTER DRILLING TSP DIAMOND CUTTERS

    SciTech Connect

    Robert Radtke

    2006-01-31

    The manufacture of thermally stable diamond (TSP) cutters for drill bits used in petroleum drilling requires the brazing of two dissimilar materials--TSP diamond and tungsten carbide. The ENDURUS{trademark} thermally stable diamond cutter developed by Technology International, Inc. exhibits (1) high attachment (shear) strength, exceeding 345 MPa (50,000 psi), (2) TSP diamond impact strength increased by 36%, (3) prevents TSP fracture when drilling hard rock, and (4) maintains a sharp edge when drilling hard and abrasive rock. A novel microwave brazing (MWB) method for joining dissimilar materials has been developed. A conventional braze filler metal is combined with microwave heating which minimizes thermal residual stress between materials with dissimilar coefficients of thermal expansion. The process results in preferential heating of the lower thermal expansion diamond material, thus providing the ability to match the thermal expansion of the dissimilar material pair. Methods for brazing with both conventional and exothermic braze filler metals have been developed. Finite element modeling (FEM) assisted in the fabrication of TSP cutters controllable thermal residual stress and high shear attachment strength. Further, a unique cutter design for absorbing shock, the densification of otherwise porous TSP diamond for increased mechanical strength, and diamond ion implantation for increased diamond fracture resistance resulted in successful drill bit tests.

  14. Hydrogen Embrittlement of Automotive Advanced High-Strength Steels

    NASA Astrophysics Data System (ADS)

    Lovicu, Gianfranco; Bottazzi, Mauro; D'Aiuto, Fabio; De Sanctis, Massimo; Dimatteo, Antonella; Santus, Ciro; Valentini, Renzo

    2012-11-01

    Advanced high-strength steels (AHSS) have a better combination between strength and ductility than conventional HSS, and higher crash resistances are obtained in concomitance with weight reduction of car structural components. These steels have been developed in the last few decades, and their use is rapidly increasing. Notwithstanding, some of their important features have to be still understood and studied in order to completely characterize their service behavior. In particular, the high mechanical resistance of AHSS makes hydrogen-related problems a great concern for this steel grade. This article investigates the hydrogen embrittlement (HE) of four AHSS steels. The behavior of one transformation induced plasticity (TRIP), two martensitic with different strength levels, and one hot-stamping steels has been studied using slow strain rate tensile (SSRT) tests on electrochemically hydrogenated notched samples. The embrittlement susceptibility of these AHSS steels has been correlated mainly to their strength level and to their microstructural features. Finally, the hydrogen critical concentrations for HE, established by SSRT tests, have been compared to hydrogen contents absorbed during the painting process of a body in white (BIW) structure, experimentally determined during a real cycle in an industrial plant.

  15. Mechanical Properties of Heat Affected Zone of High Strength Steels

    NASA Astrophysics Data System (ADS)

    Sefcikova, K.; Brtnik, T.; Dolejs, J.; Keltamaki, K.; Topilla, R.

    2015-11-01

    High Strength Steels became more popular as a construction material during last decade because of their increased availability and affordability. On the other hand, even though general use of Advanced High Strength Steels (AHSS) is expanding, the wide utilization is limited because of insufficient information about their behaviour in structures. The most widely used technique for joining steels is fusion welding. The welding process has an influence not only on the welded connection but on the area near this connection, the so-called heat affected zone, as well. For that reason it is very important to be able to determine the properties in the heat affected zone (HAZ). This area of investigation is being continuously developed in dependence on significant progress in material production, especially regarding new types of steels available. There are currently several types of AHSS on the world market. Two most widely used processes for AHSS production are Thermo-Mechanically Controlled Processing (TMCP) and Quenching in connection with Tempering. In the presented study, TMCP and QC steels grade S960 were investigated. The study is focused on the changes of strength, ductility, hardness and impact strength in heat affected zone based on the used amount of heat input.

  16. High current high accuracy IGBT pulse generator

    SciTech Connect

    Nesterov, V.V.; Donaldson, A.R.

    1995-05-01

    A solid state pulse generator capable of delivering high current triangular or trapezoidal pulses into an inductive load has been developed at SLAC. Energy stored in a capacitor bank of the pulse generator is switched to the load through a pair of insulated gate bipolar transistors (IGBT). The circuit can then recover the remaining energy and transfer it back to the capacitor bank without reversing the capacitor voltage. A third IGBT device is employed to control the initial charge to the capacitor bank, a command charging technique, and to compensate for pulse to pulse power losses. The rack mounted pulse generator contains a 525 {mu}F capacitor bank. It can deliver 500 A at 900V into inductive loads up to 3 mH. The current amplitude and discharge time are controlled to 0.02% accuracy by a precision controller through the SLAC central computer system. This pulse generator drives a series pair of extraction dipoles.

  17. Oxidation resistant high creep strength austenitic stainless steel

    DOEpatents

    Brady, Michael P.; Pint, Bruce A.; Liu, Chain-Tsuan; Maziasz, Philip J.; Yamamoto, Yukinori; Lu, Zhao P.

    2010-06-29

    An austenitic stainless steel displaying high temperature oxidation and creep resistance has a composition that includes in weight percent 15 to 21 Ni, 10 to 15 Cr, 2 to 3.5 Al, 0.1 to 1 Nb, and 0.05 to 0.15 C, and that is free of or has very low levels of N, Ti and V. The alloy forms an external continuous alumina protective scale to provide a high oxidation resistance at temperatures of 700 to 800.degree. C. and forms NbC nanocarbides and a stable essentially single phase fcc austenitic matrix microstructure to give high strength and high creep resistance at these temperatures.

  18. New Powder Metallurgical Approach to Achieve High Fatigue Strength in Ti-6Al-4V Alloy

    NASA Astrophysics Data System (ADS)

    Cao, Fei; Ravi Chandran, K. S.; Kumar, Pankaj; Sun, Pei; Zak Fang, Z.; Koopman, Mark

    2016-05-01

    Recently, manufacturing of titanium by sintering and dehydrogenation of hydride powders has generated a great deal of interest. An overarching concern regarding powder metallurgy (PM) titanium is that critical mechanical properties, especially the high-cycle fatigue strength, are lower than those of wrought titanium alloys. It is demonstrated here that PM Ti-6Al-4V alloy with mechanical properties comparable (in fatigue strength) and exceeding (in tensile properties) those of wrought Ti-6Al-4V can be produced from titanium hydride powder, through the hydrogen sintering and phase transformation process. Tensile and fatigue behavior, as well as fatigue fracture mechanisms, have been investigated under three processing conditions. It is shown that a reduction in the size of extreme-sized pores by changing the hydride particle size distribution can lead to improved fatigue strength. Further densification by pneumatic isostatic forging leads to a fatigue strength of ~550 MPa, comparable to the best of PM Ti-6Al-4V alloys prepared by other methods and approaching the fatigue strengths of wrought Ti-6Al-4V alloys. The microstructural factors that limit fatigue strength in PM titanium have been investigated, and pathways to achieve greater fatigue strengths in PM Ti-6Al-4V alloys have been identified.

  19. Identification of orthorhombic phase in a high-strength cupronickel

    SciTech Connect

    Grylls, R.J.; Loretto, M.H.; Tuck, C.D.S.

    1996-01-01

    MARINEL is the latest alloy in a series of high-strength, age-hardenable wrought cupronickels. It combines excellent resistance to corrosion and hydrogen embrittlement with high strength and is designed particularly for use in critical subsea bolting applications. Strengthening is provided by additions of Mn, Al, Fe, Nb and Cr. In this work the microstructure of MARINEL has been studied using optical and electron microscopy with the aim of understanding the strengthening mechanisms. As part of this major program the predominant micron-scale phase has been analyzed in some detail. This paper describes the composition and crystal structure of this phase, and identifies it as the {var_epsilon} phase already seen in Incoloy alloy 909.

  20. NDE detectability of fatigue type cracks in high strength alloys

    NASA Technical Reports Server (NTRS)

    Christner, B. K.; Rummel, W. D.

    1983-01-01

    Specimens suitable for investigating the reliability of production nondestructive evaluation (NDE) to detect tightly closed fatigue cracks in high strength alloys representative of those materials used in spacecraft engine/booster construction were produced. Inconel 718 was selected as representative of nickel base alloys and Haynes 188 was selected as representative of cobalt base alloys used in this application. Cleaning procedures were developed to insure the reusability of the test specimens and a flaw detection reliability assessment of the fluorescent penetrant inspection method was performed using the test specimens produced to characterize their use for future reliability assessments and to provide additional NDE flaw detection reliability data for high strength alloys. The statistical analysis of the fluorescent penetrant inspection data was performed to determine the detection reliabilities for each inspection at a 90% probability/95% confidence level.

  1. Grain refinement of high strength steels to improve cryogenic toughness

    NASA Technical Reports Server (NTRS)

    Rush, H. F.

    1985-01-01

    Grain-refining techniques using multistep heat treatments to reduce the grain size of five commercial high-strength steels were investigated. The goal of this investigation was to improve the low-temperature toughness as measured by Charpy V-notch impact test without a significant loss in tensile strength. The grain size of four of five alloys investigated was successfully reduced up to 1/10 of original size or smaller with increases in Charpy impact energy of 50 to 180 percent at -320 F. Tensile properties were reduced from 0 to 25 percent for the various alloys tested. An unexpected but highly beneficial side effect from grain refining was improved machinability.

  2. Reduced hydrogen embrittlement susceptibility in platinum implanted high strength steel

    NASA Astrophysics Data System (ADS)

    Cowie, J. G.; Lowder, L. J.; Culbertson, R. J.; Kosik, W. E.; Brown, R.

    1991-07-01

    High strength steels suffer from a high susceptibility to hydrogen embrittlement in a corrosive atmosphere, a factor which limits their usefulness. A good catalyst, such as platinum, present on the surface of the steel may lead to a low value of hydrogen overvoltage, thereby reducing the accumulation and subsequent diffusion of atomic hydrogen into the metal. In the present study, platinum was implanted into high strength electroslag remelted (ESR) 4340 steel specimens to a dose of 10 16 atoms/cm 2. Both Pt-implanted and unimplanted specimens were rate charged with hydrogen. The relative concentration of diffusible hydrogen was determined using an electrochemical measurement device known as a Barnacle Electrode. The specimens implanted with platinum exhibited less diffusible hydrogen than the unimplanted steel. Slow strain rate notched-tensile tests, in an aqueous solution of 3.5 wt.% NaCI, were performed in order to evaluate the effect of hydrogen on strength and ductility. The Pt-implanted specimens were able to sustain significantly higher loads before fracture than their unimplanted counterparts. Scanning electron microscopy (SEM) verified the presence of brittle cracking typical of hydrogen embrittlement type failures. Degradation of mechanical properties due to hydrogen embrittlement was thus significantly reduced. This suggested that both the electrochemical and catalytic properties of the Pt-implanted surface were responsible for the improvement in properties.

  3. Qualitative and quantitative fracture analyses of high-strength ceramics.

    PubMed

    Øilo, Marit; Tvinnereim, Helene M; Gjerdet, Nils R

    2009-04-01

    The aims of this study were to assess the applicability and repeatability of qualitative and quantitative analyses of the fracture patterns of four different high-strength ceramics. Ten bar-shaped specimens of four high-strength ceramics with different material composition and fabrication methods had been fractured by three-point bending in water (n = 40). Commonly used fractographic patterns for brittle materials, such as mirror and mist, were used to characterize and quantify the fractured surfaces of these specimens. The analyses were performed twice, on separate occasions, by the same operator. Assessment of the association between fractographic patterns and fracture stress was carried out, and repeatability assessments of the measurements were performed. The fracture initiator site and the common fractographic markers surrounding this site were found in all specimens. Statistically significant correlations were found between certain fracture patterns and stress at fracture. The repeatability of the measurements of the different fractographic patterns varied among the materials. Fracture analyses seem applicable as a tool to determine the fracture initiation site and to estimate the force vectors involved in the fracture of dental high-strength ceramics. PMID:19320729

  4. Development of ductile high-strength chromium alloys, phase 2

    NASA Technical Reports Server (NTRS)

    Filippi, A. M.

    1973-01-01

    Strength and ductility were evaluated for chromium alloys dispersion hardened with the putative TaC, TaB, CbC, and CbB compounds. TaC and TaB proved to be the most potent strengtheners, but when combined, their effect far outweighed that produced individually. Tests at 1422 K (2100 F) on an alloy containing these two compounds at the combined level of 0.5 m/o revealed a 495 MN/sq m (70 ksi) tensile strength for wrought material, and a 100 hour rupture strength of 208 MN/sq m (30 ksi) when solution annealed and aged to maximize creep resistance. These levels of high temperature strength greatly exceed that reported for any other chromium-base alloy. The ductile-to-brittle transition temperature (DBTT) of the two phase strengthened alloy occurred at approximately 588 K (600 F) when heat treated to optimize creep strength and was not improved by fabrication to produce a wrought and recovered microstructure. The lowest DBTT measured on any of the alloys investigated was 422 K (300 F). Strengthening phases actually formed in Cr-Ta-B and Cr-Cb-B compositions are probable M2CrB2 (M=Ta or Cb) compounds of tetragonal crystal structure. The likely habit relationship between these compounds and chromium is postulated. Cube habit coherency was identified for TaC precipitation in chromium by electron microscopy. In another study, the maximum solubility of carbon in chromium was indicated to lie between 3/4 and 1 a/o and that of boron to be 1/2 a/o.

  5. High flux compact neutron generators

    SciTech Connect

    Reijonen, J.; Lou, T.-P.; Tolmachoff, B.; Leung, K.-N.; Verbeke, J.; Vujic, J.

    2001-06-15

    Compact high flux neutron generators are developed at the Lawrence Berkeley National Laboratory. The neutron production is based on D-D or D-T reaction. The deuterium or tritium ions are produced from plasma using either a 2 MHz or 13.56 MHz radio frequency (RF) discharge. RF-discharge yields high fraction of atomic species in the beam which enables higher neutron output. In the first tube design, the ion beam is formed using a multiple hole accelerator column. The beam is accelerated to energy of 80 keV by means of a three-electrode extraction system. The ion beam then impinges on a titanium target where either the 2.4 MeV D-D or 14 MeV D-T neutrons are generated. The MCNP computation code has predicted a neutron flux of {approximately}10{sup 11} n/s for the D-D reaction at beam intensity of 1.5 A at 150 kV. The neutron flux measurements of this tube design will be presented. Recently new compact high flux tubes are being developed which can be used for various applications. These tubes also utilize RF-discharge for plasma generation. The design of these tubes and the first measurements will be discussed in this presentation.

  6. High Strength Discontinuously Reinforced Aluminum For Rocket Applications

    NASA Technical Reports Server (NTRS)

    Pandey, A. B.; Shah, S. R.; Shadoan, M.

    2003-01-01

    This study presents results on the development of a new aluminum alloy with very high strength and ductility. Five compositions of Al-Mg-Sc-Gd-Zr alloy were selected for this purpose. These alloys were also reinforced with 15 volume percent silicon-carbide and boron-carbide particles to produce Discontinuously Reinforced Aluminum (DRA) materials. Matrix alloys and DRA were processed using a powder metallurgy process. The helium gas atomization produced very fine powder with cellular-dentritic microstructure. The microstructure of matrix alloys showed fine Al3Sc based precipitate which provides significant strengthening in these alloys. DRA showed uniform distribution of reinforcement in aluminum matrix. DRA materials were tested at -320 F, 75 F in air and 7S F in gaseous hydrogen environments and matrix alloys were tested at 75 F in air. DRA showed high strengths in the range of 89-111 ksi (614-697 MPa) depending on alloy compositions and test environments. Matrix alloys had a good combination of strength, 84-89 ksi (579-621 MPa) and ductility, 4.5-6.5%. The properties of these materials can further be improved by proper control of processing parameters.

  7. New high-strength neodymium phosphate laser glass

    SciTech Connect

    Galagan, B I; Glushchenko, I N; Denker, B I; Kalachev, Yu L; Mikhailov, Viktor A; Sverchkov, S E; Shcherbakov, Ivan A; Kuleshov, N V

    2009-12-31

    A high-strength neodymium laser glass (SNLG) based on an alumoborophosphate composition is developed and synthesised; its physicochemical, spectral, luminescent, and lasing characteristics are studied. It is found that the chemical stability and thermal resistance of the new glass are considerably higher than the corresponding characteristics of known neodymium-doped phosphate laser glasses. Investigations of lasing upon longitudinal diode pumping showed that, due to the higher thermal resistance, the new glass allows one to obtain output powers twice as high as those of industrial GLS22 glass. (active media)

  8. Preliminary Strength Measurements of High Temperature Ash Filter Deposits

    SciTech Connect

    Kang, B.S.; Johnson, E.K.; Mallela, R.; Barberio, J.F.

    1996-12-31

    The objective of this study is to develop and evaluate preliminary strength measurement techniques for high temperature candle filter ash deposits. The efficient performance of a high temperature gas filtering system is essential for many of the new thermal cycles being proposed for power plants of the future. These new cycles hold the promise of higher thermal efficiency and lower emissions of pollutants. Many of these cycles involve the combustion or gasification of coal to produce high temperature gases to eventually be used in gas turbines. These high temperature gases must be relatively free of particulates. Today, the candle filter appears to be the leading candidate for high temperature particulate removal. The performance of a candle filter depends on the ash deposits shattering into relatively large particles during the pulse cleaning (back flushing) of the filters. These relatively large particles fall into the ash hopper and are removed from the system. Therefore, these 1247 particles must be sufficiently large so that they will not be re-entrained by the gas flow. The shattering process is dictated by the strength characteristics of the ash deposits. Consequently, the objective of this research is to develop measurements for the desired strength characteristics of the ash deposits. Experimental procedures were developed to measure Young`s modulus of the ash deposit at room temperature and the failure tensile strain of ash deposits from room temperature to elevated temperatures. Preliminary data has been obtained for both soft and hard ash deposits. The qualifier ``preliminary`` is used to indicate that these measurements are a first for this material, and consequently, the measurement techniques are not perfected. In addition, the ash deposits tested are not necessarily uniform and further tests are needed in order to obtain meaningful average data.

  9. High Breakdown Strength, Multilayer Ceramics for Compact Pulsed Power Applications

    SciTech Connect

    Gilmore, B.; Huebner, W.; Krogh, M.L.; Lundstrom, J.M.; Pate, R.C.; Rinehart, L.F.; Schultz, B.C.; Zhang, S.C.

    1999-07-20

    Advanced ceramics are being developed for use in large area, high voltage devices in order to achieve high specific energy densities (>10 6 J/m 3 ) and physical size reduction. Initial materials based on slip cast TiO2 exhibited a high bulk breakdown strength (BDS >300 kV/cm) and high permittivity with low dispersion (e�100). However, strong area and thickness dependencies were noted. To increase the BDS, multilayer dielectric compositions are being developed based on glass/TiO2 composites. The addition of glass increases the density (�99.8% theoretical), forms a continuous grain boundary phase, and also allows the use of high temperature processes to change the physical shape of the dielectric. The permittivity can also be manipulated since the volume fraction and connectivity of the glassy phase can be readily shifted. Results from this study on bulk breakdown of TiO2 multilayer structures with an area of 2cm 2 and 0.1cm thickness have measured 650 kV/cm. Furthermore, a strong dependence of breakdown strength and permittivity has been observed and correlated with microstructure and the glass composition. This paper presents the interactive effects of manipulation of these variables.

  10. Examination of some high-strength, high-conductivity copper alloys for high-temperature applications

    SciTech Connect

    Dadras, M.M.; Morris, D.G.

    1997-12-22

    Copper alloys with high strength and high thermal and electrical conductivity have received a lot of attention over the last decades. Most of such efforts have concentrated on the development of alloys containing fine, dispersed particles, and using rapid solidification techniques to ensure a sufficient volume fraction and sufficient fineness of the dispersed phase. In a recent study, a Cu-8Cr-4Nb alloy was developed which shows relatively good strength up to 700 C, a result which was explained by the resistance to coarsening of the fine Cr{sub 2}Nb intermetallic particles in this materials. The amount of intermetallic Cr{sub 2}Nb second phase in this alloy was about 14vol% and it was claimed that the special compound-nature of the intermetallic phase was responsible for the good stability and retention of strength to high temperature. In order to examine the influence of the nature of the fine particles present and their stability against coarsening, as well as to examine the influence of volume fraction of second phase on tensile strength, three different alloys have been chosen for study: Cu-2Nb and Cu-4Cr for examining the role of second phase chemistry (Nb or Cr) on structural and property stability; and a Cu-14Cr alloy, for comparison with the Cu-4Cr alloy, to examine the role of volume fraction of the second phase. The stability of these alloys will then be compared with that reported for the Cu-8Cr-4Nb alloy.

  11. Harmonic generation at high intensities

    SciTech Connect

    Schafer, K.J.; Krause, J.L.; Kulander, K.C.

    1993-06-01

    Atomic electrons subject to intense laser fields can absorb many photons, leading either to multiphoton ionization or the emission of a single, energetic photon which can be a high multiple of the laser frequency. The latter process, high-order harmonic generation, has been observed experimentally using a range of laser wavelengths and intensities over the past several years. Harmonic generation spectra have a generic form: a steep decline for the low order harmonics, followed by a plateau extending to high harmonic order, and finally an abrupt cutoff beyond which no harmonics are discernible. During the plateau the harmonic production is a very weak function of the process order. Harmonic generation is a promising source of coherent, tunable radiation in the XUV to soft X-ray range which could have a variety of scientific and possibly technological applications. Its conversion from an interesting multiphoton phenomenon to a useful laboratory radiation source requires a complete understanding of both its microscopic and macroscopic aspects. We present some recent results on the response of single atoms at intensities relevant to the short pulse experiments. The calculations employ time-dependent methods, which we briefly review in the next section. Following that we discuss the behavior of the harmonics as a function of laser intensity. Two features are notable: the slow scaling of the harmonic intensities with laser intensity, and the rapid variation in the phase of the individual harmonics with respect to harmonic order. We then give a simple empirical formula that predicts the extent of the plateau for a given ionization potential, wavelength and intensity.

  12. Scratch-resistant, highly conductive, and high-strength carbon nanotube-based composite yarns.

    PubMed

    Liu, Kai; Sun, Yinghui; Lin, Xiaoyang; Zhou, Ruifeng; Wang, Jiaping; Fan, Shoushan; Jiang, Kaili

    2010-10-26

    High-strength and conductive carbon nanotube (CNT) yarns are very attractive in many potential applications. However, there is a difficulty when simultaneously enhancing the strength and conductivity of CNT yarns. Adding some polymers into CNT yarns to enhance their strength will decrease their conductivity, while treating them in acid or coating them with metal nanoparticles to enhance their conductivity will reduce their strength. To overcome this difficulty, here we report a method to make high-strength and highly conductive CNT-based composite yarns by using a continuous superaligned CNT (SACNT) yarn as a conductive framework and then inserting polyvinyl alcohol (PVA) into the intertube spaces of the framework through PVA/dimethyl sulphoxide solution to enhance the strength of yarns. The as-produced CNT/PVA composite yarns possess very high tensile strengths up to 2.0 GPa and Young's moduli more than 120 GPa, much higher than those of the CNT/PVA yarns reported. The electric conductivity of as-produced composite yarns is as high as 9.2 × 10(4) S/m, comparable to HNO(3)-treated or Au nanoparticle-coated CNT yarns. These composite yarns are flexible, lightweight, scratch-resistant, very stable in the lab environment, and resistant to extremely humid ambient and as a result can be woven into high-strength and heatable fabrics, showing potential applications in flexible heaters, bullet-proof vests, radiation protection suits, and spacesuits. PMID:20831235

  13. TOUGHREACT Testing in High Ionic Strength Brine Sandstone Systems

    SciTech Connect

    Xu, Tianfu

    2008-09-01

    Deep saline formations and oil and gas reservoirs often contain concentrated brine solutions of ionic strength greater than 1 (I > 1 M). Geochemical modeling, involving high ionic strength brines, is a challenge. In the original TOUGHREACT code (Xu et al., 2004; Xu et al., 2006), activity coefficients of charged aqueous species are computed using an extended Debye-Huckel (DH) equation and parameters derived by Helgeson et al. (1981). The DH model can deal with ionic strengths from dilute to moderately saline water (up to 6 molal for an NaCl-dominant solution). The equations implemented for the DH model are presented in Appendix A. During the course of the Yucca Mountain project, a Pitzer ion-interaction model was implemented into TOUGHREACT. This allows the application of this simulator to problems involving much more concentrated aqueous solutions, such as those involving geochemical processes in and around high-level nuclear waste repositories where fluid evaporation and/or boiling is expected to occur (Zhang et al., 2007). The Pitzer ion-interaction model, which we refer to as the Pitzer virial approach, and associated ion-interaction parameters have been applied successfully to study non-ideal concentrated aqueous solutions. The formulation of the Pitzer model is presented in Appendix B; detailed information can be founded in Zhang et al. (2007). For CO{sub 2} geological sequestration, the Pitzer ion-interaction model for highly concentrated brines was incorporated into TOUGHREACT/ECO2N, then was tested and compared with a previously implemented extended Debye-Hueckel (DH) ion activity model. The comparison was made through a batch geochemical system using a Gulf Coast sandstone saline formation.

  14. Method for providing a low density high strength polyurethane foam

    DOEpatents

    Whinnery, Jr., Leroy L.; Goods, Steven H.; Skala, Dawn M.; Henderson, Craig C.; Keifer, Patrick N.

    2013-06-18

    Disclosed is a method for making a polyurethane closed-cell foam material exhibiting a bulk density below 4 lbs/ft.sup.3 and high strength. The present embodiment uses the reaction product of a modified MDI and a sucrose/glycerine based polyether polyol resin wherein a small measured quantity of the polyol resin is "pre-reacted" with a larger quantity of the isocyanate in a defined ratio such that when the necessary remaining quantity of the polyol resin is added to the "pre-reacted" resin together with a tertiary amine catalyst and water as a blowing agent, the polymerization proceeds slowly enough to provide a stable foam body.

  15. PM alloy 625M for high strength corrosion resistant applications

    SciTech Connect

    Rizzo, F.J.; Floreen, S.

    1997-06-01

    In applications where the combination of high strength and good corrosion resistance are required, there have been only a few alloys of choice. A new powder metallurgy alloy has been developed, PM 625M, a niobium modification of Alloy 625, as a material to fill this need. One area of particular interest is the nuclear power industry, where many problems have been encountered with bolts, springs, and guidepins. Mechanical properties and stress corrosion cracking data of PM 625M are presented in this paper.

  16. Further observations on high impact strength denture-base materials.

    PubMed

    Rodford, R A; Braden, M

    1992-01-01

    Previous studies have shown that high impact strength can be conferred on denture-base poly(methyl methacrylate) polymers by modification with acrylic-terminated butadiene-styrene block copolymers, and that the acrylic end-group was necessary for effective reinforcement. It is now shown that, by solvent extraction studies, grafting of the copolymer occurs both with acrylic-terminated and non-terminated block copolymers. It is therefore concluded that the mode of grafting is different, and some possible mechanisms are discussed. PMID:1420720

  17. A new high strength alloy for hydrogen fueled propulsion systems

    NASA Technical Reports Server (NTRS)

    Mcpherson, W. B.

    1986-01-01

    This paper describes the development of a high-strength alloy (1241 MPa ultimate and 1103 MPa yield, with little or no degradation in hydrogen) for application in advanced hydrogen-fueled rocket engines. Various compositions of the Fe-Ni-Co-Cr system with elemental additions of Cb, Ti and Al are discussed. After processing, notched tensile specimens were tested in 34.5-MPa hydrogen at room temperature, as the main screening test. The H2/air notch tensile ratio was used as the selection/rejection criterion. The most promising alloys are discussed.

  18. Design of Hierarchically Cut Hinges for Highly Stretchable and Reconfigurable Metamaterials with Enhanced Strength.

    PubMed

    Tang, Yichao; Lin, Gaojian; Han, Lin; Qiu, Songgang; Yang, Shu; Yin, Jie

    2015-11-25

    Applying hierarchical cuts to thin sheets of elastomer generates super-stretchable and reconfigurable metamaterials, exhibiting highly nonlinear stress-strain behaviors and tunable phononic bandgaps. The cut concept fails on brittle thin sheets due to severe stress concentration in the rotating hinges. By engineering the local hinge shapes and global hierarchical structure, cut-based reconfigurable metamaterials with largely enhanced strength are realized. PMID:26461470

  19. Magnetic Implosion for Novel Strength Measurements at High Strain Rates

    SciTech Connect

    Lee, H.; Preston, D.L.; Bartsch, R.R.; Bowers, R.L.; Holtkamp, D.; Wright, B.L.

    1998-10-19

    Recently Lee and Preston have proposed to use magnetic implosions as a new method for measuring material strength in a regime of large strains and high strain rates inaccessible to previously established techniques. By its shockless nature, this method avoids the intrinsic difficulties associated with an earlier approach using high explosives. The authors illustrate how the stress-strain relation for an imploding liner can be obtained by measuring the velocity and temperature history of its inner surface. They discuss the physical requirements that lead us to a composite liner design applicable to different test materials, and also compare the code-simulated prediction with the measured data for the high strain-rate experiments conducted recently at LANL. Finally, they present a novel diagnostic scheme that will enable us to remove the background in the pyrometric measurement through data reduction.

  20. The Strengths of High-Achieving Black High School Students in a Racially Diverse Setting

    ERIC Educational Resources Information Center

    Marsh, Kris; Chaney, Cassandra; Jones, Derrick

    2012-01-01

    Robert Hill (1972) identified strengths of Black families: strong kinship bonds, strong work orientation, adaptability of family roles, high achievement orientation, and religious orientation. Some suggest these strengths sustain the physical, emotional, social, and spiritual needs of Blacks. This study used narratives and survey data from a…

  1. Production of high strength TMCP steel plate for offshore structures

    SciTech Connect

    Yoshida, Yuzuru; Tamehiro, Hiroshi; Chijiiwa, Rikio; Funato, Kazuo; Doi, Naoki; Tanaka, Kazuaki; Kibe, Masaomi

    1993-12-31

    Titanium-oxide bearing steel (Ti-O steel), which has improved toughness in the heat-affected zone (HAZ) by utilizing intragranular ferrite (IGF), has been developed, and successfully put into commercial production. This was also the first application of yield strength (YS) 420 N/mm{sup 2} class TMCP steel plates to offshore structures. In the Ti-O steel, IGF grows radially from Ti-oxides finely dispersed in the steel as nuclei when HAZ transforms from austenite to ferrite after welding, and thus the microstructure of the HAZ is remarkably refined. As Ti-oxide particles are chemically stable even in the region near the fusion line which was reheated to a high-temperature above 1,350 C, control of the microstructure is possible in the entire HAZ and excellent crack tip opening displacement (CTOD) properties can be obtained. By applying Ti-O steel, Nippon Steel has succeeded in the mass production (approximately 9,000 tons) of YS 420 N/mm{sup 2} class TMCP steel plate for offshore structures in the North Sea. In addition to high strength and strict CTOD properties, various other properties including low carbon equivalent, narrow YS range, etc., were required for this plate. In order to satisfy these requirements, it was necessary to take comprehensive measured in the entire production process including steel making, continuous casting and plate rolling. The Ti-O steel with low carbon equivalent satisfies the required strength and low-temperature toughness of the base material and exhibits excellent toughness in the CTOD and Charpy tests of the welded joints, and offers good field weldability. Furthermore, the YS was controlled within a narrow range of less than 100 N/mm{sup 2} by strictly controlling the range of chemical composition and the TMCP condition.

  2. Bond strength of a new generation of universal bonding systems to zirconia ceramic.

    PubMed

    Passia, Nicole; Mitsias, Miltiadis; Lehmann, Frank; Kern, Matthias

    2016-09-01

    The purpose of this laboratory study was to evaluate the tensile bond strength of a new generation of universal bonding systems to zirconia ceramic and to compare the results with the bond strength of a clinically-established bonding system. Eighty zirconia ceramic test specimens (e.max ZirCAD) were air-abraded and bonded to Plexiglas tubes, filled with an aliphatic dimethacrylate filling material (Clearfil F II), using three so called universal bonding systems of a new generation with different compositions (Monobond Plus/MultilinkAutomix, NX3, Scotchbond Universal/RelyX Ultimate). The latter was used also without the phosphate monomer containing primer Scotchbond Universal. A clinically established phosphate monomer containing adhesive cement served as control group (Panavia F2.0). The specimens were stored in water at 37°C for 3 or 150 days and the long-term storage series were additionally thermal cycled between 5 and 55°C for 37,500 times to simulate oral conditions. All specimens underwent tensile bond strength testing. The statistical analysis was performed using Kruskal-Wallis and Wilcoxon-Test with a Bonferroni-Holm correction for multiple testing. After 150 days the median bond strength of RelyX Ultimate, with and without Scotchbond Universal, and Panavia F2.0 did not differ statistically (range: 21.7-28.8MPa), while the bond strength of Monobond Plus/Multilink Automix was significantly lower (15.4MPa), and that of NX3 the lowest (6.6MPa). After 150 days of water storage with thermal cycling, all adhesive system showed significantly reduced tensile bond strengths compared to that after 3 days. Only RelyX Ultimate was comparable to the established bonding system Panavia F2.0. The additional use of Scotchbond Universal did not result in a significant effect. PMID:27232829

  3. Study on technology of high-frequency pulsed magnetic field strength measurement.

    PubMed

    Chen, Yi-Mei; Liu, Zhi-Peng; Yin, Tao

    2012-01-01

    High-frequency transient weak magnetic field is always involved in researches about biomedical engineering field while common magnetic-field sensors cannot work properly at frequencies as high as MHz. To measure the value of MHz-level weak pulsed magnetic-field strength accurately, this paper designs a measurement and calibration method for pulsed magnetic-field. In this paper, a device made of Nonferromagnetic material was independently designed and applied to pulsed magnetic field measurement. It held an accurately relative position between the magnetic field generating coil and the detecting coil. By applying a sinusoidal pulse to the generator, collecting the induced electromotive force of the detector, the final magnetic field strength was worked out through algorithms written in Matlab according to Faraday's Law. Experiments were carried out for measurement and calibration. Experiments showed that, under good stability and consistency, accurate measurement of magnetic-field strength of a sinepulse magnetic-field can be achieved, with frequency at 0.5, 1, 1.5 MHz and strength level at micro-Tesla. Calibration results carried out a measuring relative error about 2.5%. PMID:23366106

  4. Fatigue behavior of high-strength concrete under marine conditions

    SciTech Connect

    Mor, A.

    1987-01-01

    In this study, 24 high-strength reinforced concrete beams were tested in fatigue under simulated marine conditions. Low-cycle, high-magnitude loading was imposed on beams, some of which were exposed to air, and others which were submerged in water. The beams were cycled at 1 Hz, to 80% of their yield capacity in negative and positive flexure. Four concrete mixes were compared. Half of the specimens were made with lightweight aggregate (LWA), and half were made with river gravel (NWA). Half of each group contained silica-fume as partial replacement of cement (13%). By manipulating the water/cement ratio, the 28-day compressive strength of all concretes was 9500 {plus minus} 300 psi. The previously reported phenomenon of water pumping through the cracks was observed, but did not appear to be directly related to the subsequent failure. When silica fume is added to the concrete mix, the adhesion is greatly improved. LWA concrete utilizes this additional adhesion effectively. NWA concrete with silica-fume, on the other hand, is not able to utilize the increased adhesion due to microcracking. Main findings of both the fatigue and pull-out bond tests are listed.

  5. Effect of Ripple Geometry on Vortex Generation, Ejection, and Strength in Oscillatory Flow

    NASA Astrophysics Data System (ADS)

    Smith, H. D.

    2012-12-01

    Turbulent vortex structures generated around bedforms have a large potential for significant suspended sediment transport. In the nearshore, the flow separation over ripples results in the generation of a lee vortex that can entrain sediment during half of the wave cycle. As the flow reverses, the sediment-laden vortex is ejected into the water column. The vortex is translated with the reversed flow and dissipates, releasing its sediment load back to the bed. The generation and ejection processes are functions of the ripple geometry and the wave acceleration. These same processes are also present for other geometries placed near the sea bed. Studies around bottom-seated cylindrical structures have shown multiple generation and ejection events off of the lee of the cylinder during half of the wave cycle. This generation is a function of Keulegan-Carpenter number, which balances the semi-excursion of the wave to the dominant length scale of the structure. In this work, the flow over rippled beds of various geometries over a range of hydrodynamic forcing will be numerically simulated to investigate the generation, ejection mechanisms, and strength of vortices created by this interaction. The simulations will be performed with the finite-difference CFD model, FLOW-3D. An advantage to this model is its ability to resolve complicated geometries in the flow with cartesian grids. In order to resolve the complex, three-dimensional flow field over an approximately two-dimensional rippled bed, a Smagorinsky Large Eddy Simulation closure scheme will be utilized. This model configuration has been shown to accurately predict the lift and drag force coefficients for bottom-mounted cylinders under linear waves, which are dominated by vortex generation and ejection. The three-dimensional vortex structure and strength will be evaluated with swirling strength criterion. Three-dimensional isosurfaces of the swirling strength will allow for the visual identification of the interaction

  6. Experimental investigation of bond strength under high loading rates

    NASA Astrophysics Data System (ADS)

    Michal, Mathias; Keuser, Manfred; Solomos, George; Peroni, Marco; Larcher, Martin; Esteban, Beatriz

    2015-09-01

    The structural behaviour of reinforced concrete is governed significantly by the transmission of forces between steel and concrete. The bond is of special importance for the overlapping joint and anchoring of the reinforcement, where rigid bond is required. It also plays an important role in the rotational capacity of plastic hinges, where a ductile bond behaviour is preferable. Similar to the mechanical properties of concrete and steel also the characteristics of their interaction changes with the velocity of the applied loading. For smooth steel bars with its main bond mechanisms of adhesion and friction, nearly no influence of loading rate is reported in literature. In contrast, a high rate dependence can be found for the nowadays mainly used deformed bars. For mechanical interlock, where ribs of the reinforcing steel are bracing concrete material surrounding the bar, one reason can be assumed to be in direct connection with the increase of concrete compressive strength. For splitting failure of bond, characterized by the concrete tensile strength, an even higher dynamic increase is observed. For the design of Structures exposed to blast or impact loading the knowledge of a rate dependent bond stress-slip relationship is required to consider safety and economical aspects at the same time. The bond behaviour of reinforced concrete has been investigated with different experimental methods at the University of the Bundeswehr Munich (UniBw) and the Joint Research Centre (JRC) in Ispra. Both static and dynamic tests have been carried out, where innovative experimental apparatuses have been used. The bond stress-slip relationship and maximum pull-out-forces for varying diameter of the bar, concrete compressive strength and loading rates have been obtained. It is expected that these experimental results will contribute to a better understanding of the rate dependent bond behaviour and will serve for calibration of numerical models.

  7. Mechanical Properties of High Strength Al-Mg Alloy Sheet

    NASA Astrophysics Data System (ADS)

    Choi, Bong-Jae; Hong, Kyung-Eui; Kim, Young-Jig

    The aim of this research is to develop the high strength Al alloy sheet for the automotive body. For the fabrication Al-Mg alloy sheet, the composition of alloying elements was designed by the properties database and CALPHAD (Calculation Phase Diagram) approach which can predict the phases during solidification using thermodynamic database. Al-Mg alloys were designed using CALPHAD approach according to the high content of Mg with minor alloying elements. After phase predictions by CALPHAD, designed Al-Mg alloys were manufactured. Addition of Mg in Al melts were protected by dry air/Sulphur hexafluoride (SF6) mixture gas which can control the severe Mg ignition and oxidation. After rolling procedure of manufactured Al-Mg alloys, mechanical properties were examined with the variation of the heat treatment conditions.

  8. Strength of VGCF/Al Composites for High Thermal Conductivity

    NASA Astrophysics Data System (ADS)

    Fukuchi, Kohei; Sasaki, Katsuhiko; Imanishi, Terumitsu; Katagiri, Kazuaki; Kakitsuji, Atsushi; Shimizu, Akiyuki

    In this paper, the evaluation of the strength of the VGCF/Aluminum composites which have high thermal conductivity is reported. VGCF (Vapor Growth Carbon Fiber) is a kind of the Carbon nanotube (CNT) which has very high thermal conductivity as well as CNT. The composites are made by spark plasma sintering. The stress-strain curves of the composites are obtained by the tensile tests and show that the composites have brittle behavior. The brittleness of the composites increases with increase in the volume fraction of VGCF. A numerical simulation based on the micromechanics is conducted to estimate nonlinear behavior in the elastic deformation and plastic deformation of the stress-strain relations of the composites. The theories of Eshelby, Mori-Tanaka, Weibull, and Ramberg-Osgood are employed for the numerical simulation. The simulations give some information of the microstructural change in the composite related to the volume fraction of VGCF.

  9. Prediction of Microstructure in High-Strength Ductile Forging Parts

    SciTech Connect

    Urban, M.; Back, A.; Hirt, G.; Keul, C.; Bleck, W.

    2010-06-15

    Governmental, environmental and economic demands call for lighter, stiffer and at the same time cheaper products in the vehicle industry. Especially safety relevant parts have to be stiff and at the same time ductile. The strategy of this project was to improve the mechanical properties of forging steel alloys by employing a high-strength and ductile bainitic microstructure in the parts while maintaining cost effective process chains to reach these goals for high stressed forged parts. Therefore, a new steel alloy combined with an optimized process chain has been developed. To optimize the process chain with a minimum of expensive experiments, a numerical approach was developed to predict the microstructure of the steel alloy after the process chain based on FEM simulations of the forging and cooling combined with deformation-time-temperature-transformation-diagrams.

  10. Accelerated Creep Testing of High Strength Aramid Webbing

    NASA Technical Reports Server (NTRS)

    Jones, Thomas C.; Doggett, William R.; Stnfield, Clarence E.; Valverde, Omar

    2012-01-01

    A series of preliminary accelerated creep tests were performed on four variants of 12K and 24K lbf rated Vectran webbing to help develop an accelerated creep test methodology and analysis capability for high strength aramid webbings. The variants included pristine, aged, folded and stitched samples. This class of webbings is used in the restraint layer of habitable, inflatable space structures, for which the lifetime properties are currently not well characterized. The Stepped Isothermal Method was used to accelerate the creep life of the webbings and a novel stereo photogrammetry system was used to measure the full-field strains. A custom MATLAB code is described, and used to reduce the strain data to produce master creep curves for the test samples. Initial results show good correlation between replicates; however, it is clear that a larger number of samples are needed to build confidence in the consistency of the results. It is noted that local fiber breaks affect the creep response in a similar manner to increasing the load, thus raising the creep rate and reducing the time to creep failure. The stitched webbings produced the highest variance between replicates, due to the combination of higher local stresses and thread-on-fiber damage. Large variability in the strength of the webbings is also shown to have an impact on the range of predicted creep life.

  11. High-strength carbon nanotube fibre-like ribbon with high ductility and high electrical conductivity.

    PubMed

    Wang, J N; Luo, X G; Wu, T; Chen, Y

    2014-01-01

    Macroscopic fibres made up of carbon nanotubes exhibit properties far below theoretical predictions and even much lower than those for conventional carbon fibres. Here we report improvements of mechanical and electrical properties by more than one order of magnitude by pressurized rolling. Our carbon nanotubes self-assemble to a hollow macroscopic cylinder in a tube reactor operated at high temperature and then condense in water or ethanol to form a fibre, which is continually spooled in an open-air environment. This initial fibre is densified by rolling under pressure, leading to a combination of high tensile strength (3.76-5.53 GPa), high tensile ductility (8-13%) and high electrical conductivity ((1.82-2.24) × 10(4) S cm(-1)). Our study therefore demonstrates strategies for future performance maximization and the very considerable potential of carbon nanotube assemblies for high-end uses. PMID:24964266

  12. Strength and flexibility of bulk high-{Tc} superconductors

    SciTech Connect

    Goretta, K.C.; Jiang, M.; Kupperman, D.S.; Lanagan, M.T.; Singh, J.P.; Vasanthamohan, N.; Hinks, D.G.; Mitchell, J.F.; Richardson, J.W. Jr.

    1996-08-01

    Strength, fracture toughness, and elastic modulus data have been gathered for bulk high-temperature superconductors, commercial 99.9% Ag, and a 1.2 at.% Mg/Ag alloy. These data have been used to calculate fracture strains for bulk conductors. The calculations indicate that the superconducting cores of clad tapes should begin to fracture at strains below 0.2%. In addition, residual strains in Ag-clad (Bi,Pb){sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub x} tapes have been measured by neutron diffraction. An explanation is offered for why many tapes appear to be able to tolerate large strains before exhibiting a reduction in current transport.

  13. Method of making high strength, tough alloy steel

    DOEpatents

    Thomas, Gareth; Rao, Bangaru V. N.

    1979-01-01

    A high strength, tough alloy steel, particularly suitable for the mining industry, is formed by heating the steel to a temperature in the austenite range (1000.degree.-1100.degree. C.) to form a homogeneous austenite phase and then cooling the steel to form a microstructure of uniformly dispersed dislocated martensite separated by continuous thin boundary films of stabilized retained austenite. The steel includes 0.2-0.35 weight % carbon, at least 1% and preferably 3-4.5% chromium, and at least one other subsitutional alloying element, preferably manganese or nickel. The austenite film is stable to subsequent heat treatment as by tempering (below 300.degree. C.) and reforms to a stable film after austenite grain refinement.

  14. Thermal Transport in High-Strength Polymethacrylimide (PMI) Foam Insulations

    NASA Astrophysics Data System (ADS)

    Qiu, L.; Zheng, X. H.; Zhu, J.; Tang, D. W.; Yang, S. Y.; Hu, A. J.; Wang, L. L.; Li, S. S.

    2015-11-01

    Thermal transport in high-strength polymethacrylimide (PMI) foam insulations is described, with special emphasis on the density and temperature effects on the thermal transport performance. Measurements of the effective thermal conductivity are performed by a freestanding sensor-based 3ω method. A linear relationship between the density and the effective thermal conductivity is observed. Based on the analysis of the foam insulation morphological structures and the corresponding geometrical cell model, the quantitative contribution of the solid conductivity and the gas conductivity as well as the radiative conductivity to the total effective thermal conductivity as a function of the density and temperature is calculated. The agreement between the curves of the results from the developed model and experimental data indicate the model can be used for PMI foam insulating performance optimization.

  15. Electron impact collision strengths for excitation of highly charged ions

    SciTech Connect

    Sampson, D.H. . Dept. of Astronomy and Astrophysics)

    1990-08-20

    The principle task given us by the Lawrence Livermore National Laboratory (LLNL) to perform under Subcontract 6181405 was to develop a method and corresponding computer programs to make very rapid, yet accurate, fully relativistic and quasirelativistic calculations of cross sections or collision strengths for electron impact excitation of highly charged ions with any value for the nuclear charge number Z. Also while this major code development was being done we were asked to calculate cross sections of interest using our previous rapid, more approximate codes, which used hydrogenic basis functions and screening constants with both the electron-electron Coulomb interaction and relativistic interactions included by perturbation theory. We were also asked to determine the branching ratio for ionization to various final states in complex cases, where two or more states corresponding to the final configuration of the ion were possible.

  16. Design of a low-alloy high-strength and high-toughness martensitic steel

    NASA Astrophysics Data System (ADS)

    Zhao, Yan-jun; Ren, Xue-ping; Yang, Wen-chao; Zang, Yue

    2013-08-01

    To develop a high strength low alloy (HSLA) steel with high strength and high toughness, a series of martensitic steels were studied through alloying with various elements and thermodynamic simulation. The microstructure and mechanical properties of the designed steel were investigated by optical microscopy, scanning electron microscopy, tensile testing and Charpy impact test. The results show that cementite exists between 500°C and 700°C, M7C3 exits below 720°C, and they are much lower than the austenitizing temperature of the designed steel. Furthermore, the Ti(C,N) precipitate exists until 1280°C, which refines the microstructure and increases the strength and toughness. The optimal alloying components are 0.19% C, 1.19% Si, 2.83% Mn, 1.24% Ni, and 0.049% Ti; the tensile strength and the V notch impact toughness of the designed steel are more than 1500 MPa and 100 J, respectively.

  17. Corrosion and embrittlement of high-strength steel bridge wires

    NASA Astrophysics Data System (ADS)

    Vermaas, Garry Wayne

    Suspension bridge cable inspections have revealed severely corroded and broken wires in some main cables. Accelerated cyclic corrosion studies were conducted to assess the relative effect of corrosion on high-strength steel bridge wire. Galvanized and ungalvanized wire samples were corroded under various levels of sustained loads in a cabinet that cyclically applied an acidic salt spray, dry conditions, and 100% relative humidity at elevated temperature. Mass loss, hydrogen concentration, ultimate load, and elongation at failure were measured for corroded and uncorroded samples. Elongation measurements indicated a significant embrittlement of the wires that could not be explained only by the presence of absorbed hydrogen (hydrogen embrittlement). The main cause of reduction of wire elongation was found to be the surface irregularities induced by the corrosion process. The corrosion process in a high-strength steel wire was modeled and analyzed using finite element methods. Forty-one separate FEM tests were run and this data was compared to the experimental data. In addition, for the purpose of comparison, a previously developed hydrogen embrittlement model was analyzed and its validity was discussed in detail. SEM photographs of the fracture surfaces were taken and possible causes and mechanisms of fracture were suggested by observations of the fracture morphology. It was shown through this experimental and numerical research work that the geometry of the wire, determined by the amount of corrosion, pitting, and surface irregularities, controls the ultimate elongation of the wire sample, as also confirmed by the SEM analysis of the fracture surfaces. It was also shown that, using a generally accepted hydrogen embrittlement model, there is no evidence that hydrogen embrittlement is occurring, or at least that hydrogen evolution is not the controlling factor in the loss of wire's ductility.

  18. High-strength, thermally-stable nanostructured materials

    NASA Astrophysics Data System (ADS)

    Shankar, Ravi

    The properties of two technologically important precipitation-treatable alloys - Al 6061 and Inconel 718, that are deformed to large plastic strains at room temperature by machining, are presented. The strong effect of prior density of precipitates on the consequent microstructure refinement during chip formation was determined by deforming Al 6061 of different tempers to varying levels of strain, by varying the tool rake angle. Chips cut from peak-aged 6061, consisting of a fine dispersion of precipitates, produced the finest microstructure and are composed of sub-100 nm grains. On the other hand, coarser precipitate distributions in over-aged 6061 and an absence of precipitates in solution-treated 6061 resulted in much coarser microstructures. Thermal stability of such nanostructured chips with different levels of strain and precipitate distributions is analyzed by studying evolution of Vickers micro-hardness and microstructure after different heat treatments. Chips produced from the peak-aged temper and over-aged temper soften following heat treatment while those from the solution-treated state first, gain strength before softening. The results are rationalized based on prior studies of the characteristics and kinetics of precipitation and coarsening in Al-Mg-Si systems. It is then demonstrated that precipitate-stabilized nanostructured materials synthesized from a prototypical alloy system - Inconel 718, are extremely stable even after prolonged heat treatment for 240 hours at temperatures as high as one-half of the melting point. This extraordinary thermal stability is traced to the retention of a fine dispersion of precipitates in a nanostructured matrix even after extended heat treatment. It is anticipated that general design principles garnered from understanding of the causal phenomena determining strengthening and thermal stability, can lead to the development of alloy systems for the manufacture of high-strength, thermally-stable nanostructured materials.

  19. Advanced Gear Alloys for Ultra High Strength Applications

    NASA Technical Reports Server (NTRS)

    Shen, Tony; Krantz, Timothy; Sebastian, Jason

    2011-01-01

    Single tooth bending fatigue (STBF) test data of UHS Ferrium C61 and C64 alloys are presented in comparison with historical test data of conventional gear steels (9310 and Pyrowear 53) with comparable statistical analysis methods. Pitting and scoring tests of C61 and C64 are works in progress. Boeing statistical analysis of STBF test data for the four gear steels (C61, C64, 9310 and Pyrowear 53) indicates that the UHS grades exhibit increases in fatigue strength in the low cycle fatigue (LCF) regime. In the high cycle fatigue (HCF) regime, the UHS steels exhibit better mean fatigue strength endurance limit behavior (particularly as compared to Pyrowear 53). However, due to considerable scatter in the UHS test data, the anticipated overall benefits of the UHS grades in bending fatigue have not been fully demonstrated. Based on all the test data and on Boeing s analysis, C61 has been selected by Boeing as the gear steel for the final ERDS demonstrator test gearboxes. In terms of potential follow-up work, detailed physics-based, micromechanical analysis and modeling of the fatigue data would allow for a better understanding of the causes of the experimental scatter, and of the transition from high-stress LCF (surface-dominated) to low-stress HCF (subsurface-dominated) fatigue failure. Additional STBF test data and failure analysis work, particularly in the HCF regime and around the endurance limit stress, could allow for better statistical confidence and could reduce the observed effects of experimental test scatter. Finally, the need for further optimization of the residual compressive stress profiles of the UHS steels (resulting from carburization and peening) is noted, particularly for the case of the higher hardness C64 material.

  20. Fracture strength of glass chips for high-pressure microfluidics

    NASA Astrophysics Data System (ADS)

    Andersson, Martin; Hjort, Klas; Klintberg, Lena

    2016-09-01

    High-pressure microfluidics exposes new areas in chemistry. In this paper, the reliability of transparent borosilicate glass chips is investigated. Two designs of circular cavities are used for fracture strength tests, either 1.6 mm wide with rounded corners to the fluid inlets, or 2.0 mm wide with sharp inlet corners. Two kinds of tests are done, either short-term, e.g. pressurization to fracture at room temperature, or long-term, with fracture at constant pressurization for up to one week, in the temperature region 11–125 °C. The speed of crack fronts is measured using a high-speed camera. Results show fracture stresses in the range of 129 and 254 MPa for short-term measurements. Long-term measurements conclude the presences of a temperature and stress dependent delayed fracture. For a reliability of one week at 11–38 °C, a pressure limit is found at the lower end of the short-term measurements, or 15% lower than the average. At 80 °C, this pressure limit is 45% lower. Crack speeds are measured to be 10‑5 m s‑1 during short-term fracture. These measurements are comparable with estimations based on slow crack growth and show that the growth affects the reliability of glass chips. This effect is strongly affected by high temperatures, thus lowers the operating window of high-pressure glass microfluidic devices.

  1. Anomalous softening of yield strength in tantalum at high pressures

    SciTech Connect

    Jing, Qiumin Wu, Qiang; Xu, Ji-an; Bi, Yan; Liu, Lei; Liu, Shenggang; Zhang, Yi; Geng, Huayun

    2015-02-07

    The pressure dependence of the yield strength of tantalum was investigated experimentally up to 101 GPa at room temperature using a diamond anvil cell. A yield strength softening is observed between 52 and 84 GPa, whereas a normal trend is observed below 52 GPa and above 84 GPa. The onset pressure of the softening is in agreement with previous results obtained by the pressure gradient method and shock wave experiments. This unusual strength softening in tantalum is not related with structural transformation, preferred orientation, or material damage. Our measurements indicate that microscopic deviatoric strain is the major reason for the observed strength softening in tantalum.

  2. Extracting strength from high pressure ramp-release experiments

    SciTech Connect

    Brown, J. L.; Alexander, C. S.; Asay, J. R.; Vogler, T. J.; Ding, J. L.

    2013-12-14

    Unloading from a plastically deformed state has long been recognized as a sensitive measure of a material's deviatoric response. In the case of a ramp compression and unload, time resolved particle velocity measurements of a sample/window interface may be used to gain insight into the sample material's strength. Unfortunately, measurements of this type are often highly perturbed by wave interactions associated with impedance mismatches. Additionally, wave attenuation, the finite pressure range over which the material elastically unloads, and rate effects further complicate the analysis. Here, we present a methodology that overcomes these shortcomings to accurately calculate a mean shear stress near peak compression for experiments of this type. A new interpretation of the self-consistent strength analysis is presented and then validated through the analysis of synthetic data sets on tantalum to 250 GPa. The synthetic analyses suggest that the calculated shear stresses are within 3% of the simulated values obtained using both rate-dependent and rate-independent constitutive models. Window effects are addressed by a new technique referred to as the transfer function approach, where numerical simulations are used to define a mapping to transform the experimental measurements to in situ velocities. The transfer function represents a robust methodology to account for complex wave interactions and a dramatic improvement over the incremental impedance matching methods traditionally used. The technique is validated using experiments performed on both lithium fluoride and tantalum ramp compressed to peak stresses of 10 and 15 GPa, respectively. In each case, various windows of different shock impedance are used to ensure consistency within the transfer function analysis. The data are found to be independent of the window used and in good agreement with previous results.

  3. Engineering problems in ensuring the strength and reliability of the new generation of aircraft engines

    SciTech Connect

    Boguslaev, V.A.

    1995-11-01

    The {open_quotes}Motor Sich{close_quotes} plant - formerly the Zaporozh`e Engine Plant - has been a major contributor to the genesis and development of the domestic aviation industry. More than 20,000 engines made at the plant are currently operating in 18 domestic models of airplanes and helicopters, while roughly 4000 of the factory`s engines are in use abroad. Also, 998 mobile gas-turbine power plants of the PAES-2500 type are presently in service in and outside the CIS. Successes such as these are the result of the tremendous effort put forth by plant personnel and close collaboration with aircraft designers and buyers and scientific-research institutes on engine manufacture, operation, and servicing. Their contributions have made it possible to improve the strength and reliability of engines AI-20, AI-241 AI-25, AI-25TL, and TVZ-117. These models are renowned most of all for their durability, surpassing comparable foreign makes with respect to length of service. Engines AI-20, AI-24, and AI-25 have an average service life of 200,000 h, versus the 50,000 h life of foreign counterparts {open_quotes}Tyne,{close_quotes} {open_quotes}Dart,{close_quotes} and TE.731. At present, engine model D-18T is still not the equal of comparable foreign-made engines in terms of reliability and service life. This can be attributed to both to the problems associated with designing high-thrust engines and to the lack of adequate diagnostic systems. After several problems are resolved, new-generation engines D-36, D-136, and D-18 will provide new levels of reliability and durability. The durability of the D-36 is presently limited by the life of the casing of the combustor (6053 cycles) and the disks of the low- and high-pressure compressors (6500-7000 cycles). The life of the D-18T is restricted mainly by the life of the rotor blades in the high-pressure turbine, defects in the disks of the high-pressure compressor, and other problems.

  4. EXPERIMENTAL STUDY ON THE APPLICATION OF HIGH STRENGTH FIBER REINFORCED MORTAR TO PRESTRESSED CONCRETE STRUCTURES

    NASA Astrophysics Data System (ADS)

    Sakurada, Michihiro; Mori, Takuya; Ohyama, Hiroaki; Seki, Hiroshi

    In order to study the application of high strength fiber reinforced mortar which has design compressive strength 120N/mm2 to prestressed concrete structures, the authors carried out material tests, bending tests and shear tests of prestressed concrete beam specimens. From the material tests, we obtained material properties for the design of prestressed concrete structures such as compressive strength, tensile strength, Young's modulus, coefficient of creep, dry shrinkage and so on. The results of the bending tests and the shear tests of prestressed concrete beam specimen shows that experimental flexural strength and shear strength of prestressed concrete beam using high strength fiber reinforced mortar exceeds strength calculated by traditional design method. It is confirmed that high strength fiber reinforced mortar can be applied to prestressed concrete structures.

  5. High precision triangular waveform generator

    DOEpatents

    Mueller, Theodore R.

    1983-01-01

    An ultra-linear ramp generator having separately programmable ascending and descending ramp rates and voltages is provided. Two constant current sources provide the ramp through an integrator. Switching of the current at current source inputs rather than at the integrator input eliminates switching transients and contributes to the waveform precision. The triangular waveforms produced by the waveform generator are characterized by accurate reproduction and low drift over periods of several hours. The ascending and descending slopes are independently selectable.

  6. High strength glass-ceramic to metal seals

    SciTech Connect

    Haws, L D; Kramer, D P; Moddeman, W E; Wooten, G W

    1986-12-01

    In many applications, ceramics are joined to other materials, especially metals. In such cases, interfacial strength is as important as the strength of each constituent material. Examples are presented for tailoring materials and processes to optimize the glass-ceramic-to-metal seal. Means for detecting defects, nondestructively, are also identified.

  7. High-strength nanocellulose-talc hybrid barrier films.

    PubMed

    Liimatainen, Henrikki; Ezekiel, Ngesa; Sliz, Rafal; Ohenoja, Katja; Sirviö, Juho Antti; Berglund, Lars; Hormi, Osmo; Niinimäki, Jouko

    2013-12-26

    Hybrid organic-inorganic films mimicking natural nacre-like composite structures were fabricated from cellulose nanofibers obtained from sequential periodate-chlorite oxidation treatment and talc platelets, using a simple vacuum-filtration method. As a pretreatment, commercial talc aggregates were individualized into well-dispersed talc platelets using a wet stirred media mill with high-shear conditions to promote the homogeneity and mechanical characteristics of hybrids. The nanofiber-talc hybrids, which had talc contents from 1 to 50 wt %, were all flexible in bending, and possessed tensile strength and Young's modulus values up to 211 ± 3 MPa and 12 ± 1 GPa, respectively, the values being remarkably higher than those reported previously for nanofibrillated cellulose-talc films. Because of the lamellar and well-organized structure of hybrids in which the talc platelets were evenly embedded, they possessed a small pore size and good oxygen barrier properties, as indicated by the preliminary results. The talc platelets decreased the moisture adsorption of highly talc-loaded hybrids, although they still exhibited hydrophilic surface characteristics in terms of contact angles. PMID:24215630

  8. High Strength Lightweight Nanocomposite from Domestic Solid Waste

    NASA Astrophysics Data System (ADS)

    Masturi, Swardhani, Anggi Puspita; Sustini, Euis; Bukit, Minsyahril; Mora, Khairurrijal, Abdullah, Mikrajuddin

    2010-10-01

    The issue of waste problems needs innovative efforts to solve. One of them is solid waste utilization as nanocomposite using polyurethane (PU) polymer as matrix. Beside using solid waste as filler, nanosilica is also added to improve the material strength of composite-produced. These materials were mixed by simple mixing with variative compositions, and then hot-pressed at 30 MPa and 100° C for 30 minutes. From compressive strength test, it was found that composite with composition 2:8 of PU and solid waste has optimum compressive strength, i.e. 160 MPa. Into this optimum composition, nanosilica then is added to improve the compressive strength and found that at composition 1:40:160 of nanosilica, PU and solid waste, the composite has optimum compressive strength 200 MPa, or increases 25% of that without nanosilica. The composite-produced is also lightweight material with the density is 0.69 g/cm.

  9. Relative fascicle excursion effects on dynamic strength generation during gait in children with cerebral palsy.

    PubMed

    Martín Lorenzo, T; Lerma Lara, S; Martínez-Caballero, I; Rocon, E

    2015-10-01

    Evaluation of muscle structure gives us a better understanding of how muscles contribute to force generation which is significantly altered in children with cerebral palsy (CP). While most muscle structure parameters have shown to be significantly correlated to different expressions of strength development in children with CP and typically developing (TD) children, conflicting results are found for muscle fascicle length. Muscle fascicle length determines muscle excursion and velocity, and contrary to what might be expected, correlations of fascicle length to rate of force development have not been found for children with CP. The lack of correlation between muscle fascicle length and rate of force development in children with CP could be due, on the one hand, to the non-optimal joint position adopted for force generation on the isometric strength tests as compared to the position of TD children. On the other hand, the lack of correlation could be due to the erroneous assumption that muscle fascicle length is representative of sarcomere length. Thus, the relationship between muscle architecture parameters reflecting sarcomere length, such as relative fascicle excursions and dynamic power generation, should be assessed. Understanding of the underlying mechanisms of weakness in children with CP is key for individualized prescription and assessment of muscle-targeted interventions. Findings could imply the detection of children operating on the descending limb of the sarcomere length-tension curve, which in turn might be at greater risk of developing crouch gait. Furthermore, relative muscle fascicle excursions could be used as a predictive variable of outcomes related to crouch gait prevention treatments such as strength training. PMID:26138625

  10. High-strength alloy with resistance to hydrogen-environment embrittlement

    NASA Technical Reports Server (NTRS)

    Mcnamara, T. G.

    1975-01-01

    Alloy is precipitation-hardened, high-strength, and low-thermal-expansion materials. It is iron-based and contains nickel and chromium at lower levels than high-strength alloys. It is readily welded and brazed and has good oxidation resistance. Tests indicated there was no reduction of notched or smooth strength.

  11. Ground level signal strength of electromagnetic waves generated by pulsed electron beams in space

    NASA Astrophysics Data System (ADS)

    Harker, K. J.; Neubert, T.; Banks, P. M.; Fraser-Smith, A. C.; Donohue, D. J.

    1991-11-01

    A theoretical study has been made of the signal strengths at ground level of waves generated by pulsed electron beams in space. The radiated energy is first calculated by an improved version of a theory based on coherent spontaneous emission. This theory evaluates the electric and magnetic field strengths and power fluxes in the far field by applying asymptotic expansion techniques. The power flowing out within a cone whose apex is located at the gun position is calculated, and the intersection of the rays in this cone with the earth's surface is determined by using Snell's law considerations. Ground signal levels are calculated for typical ionospheric conditions as a function of pulsing frequency for fixed beam voltage and for voltage adjusted for resonance between the waves and the particles. For short beams, the ground level signal strengths are relatively insensitive to the wave particle resonance condition, but for longer beams the associated peaking of the signal level begins to be observed. Finally, these results are compared against ambient noise levels to determine under which circumstances these ground signals can be detected.

  12. Orbital Winch for High-Strength, Space-Survivable Tethers

    NASA Technical Reports Server (NTRS)

    Hoyt, Robert; Barnes, Ian; Slostad, Jeffrey; Frank, Scott

    2010-01-01

    An Orbital Winch mechanism enables high-load, multi-line tethers to be deployed and retracted without rotating the spool on which the tether is wound. To minimize damage to the tether and the wound package during retraction or deployment under load, it can incorporate a Tension Management Module that reduces the infeed tension by a factor of 15 through the use of a powered capstan with guide rollers. This design eliminates the need for rotating high-voltage electrical connections in tether systems that use propellantless electro-dynamic propulsion. It can also eliminate the need for rotating optical connections in applications where the tether contains optical fibers. This winch design was developed to deploy a 15-km-long, 15-kg high-strength Hoytether structure incorporating conductive wires as part of the MXER-1 demonstration mission concept. Two slewing rings that orbit around the tether spool, combined with translation of one of the slewing rings back and forth along the spool axis to traverse the wind point, enables the winch to wind the tether. Variations of the traverse motion of the slewing ring can accomplish level winds and conical pirn winds. By removing the non-traversing slewing ring, and adding an actuated guide arm, the winch can manage rapid, low-drag deployment of a tether off the end of a pirn-wound spool, followed by controlled retraction and rewinding, in a manner very similar to a spin-casting reel. The winch requires at least two motor driver controller units to coordinate the action of two stepper motors to accomplish tether deployment or retraction.

  13. A lightweight, high strength dexterous manipulator for commercial applications

    NASA Technical Reports Server (NTRS)

    Marzwell, Neville I.; Schena, Bruce M.; Cohan, Steve M.

    1991-01-01

    The concept, design, and features are described of a lightweight, high strength, modular robot manipulator being developed for space and commercial applications. The manipulator has seven fully active degrees of freedom and is fully operational in 1 G. Each of the seven joints incorporates a unique drivetrain design which provides zero backlash operation, is insensitive to wear, and is single fault tolerant to motor or servo amplifier failure. Feedback sensors provide position, velocity, torque, and motor winding temperature information at each joint. This sensing system is also designed to be single fault tolerant. The manipulator consists of five modules (not including gripper). These modules join via simple quick-disconnect couplings and self-mating connectors which allow rapid assembly and/or disassembly for reconfiguration, transport, or servicing. The manipulator is a completely enclosed assembly, with no exposed components or wires. Although the initial prototype will not be space qualified, the design is well suited to meeting space requirements. The control system provides dexterous motion by controlling the endpoint location and arm pose simultaneously. Potential applications are discussed.

  14. High strength nitrogen removal from nightsoil and piggery wastes.

    PubMed

    Choi, E; Eum, Y; Gil, K I; Oa, S W

    2004-01-01

    Nightsoil and piggery wastes generally present high strength organics and nitrogen. This study evaluated the nitrogen removal characteristics with the existing and modified nightsoil and piggery waste treatment plants. The existing conventional plants showed 20 to 40% nitrogen removal, but the modification with SBR or MLE process could remove effectively both nitrogen and organics with the minimum COD/TN and alkalinity/TN ratios of 6 and 3.6, respectively. Nitrite nitrification and denitrification rates obtainable at higher nitrogen loads were faster than the rates of nitrate nitrification and denitrification resulting in less reactor volume requirement. However, the higher nitrogen loads increased the organic loads resulting in the reactor temperature inhibiting nitrification. Thus, a combined treatment with anaerobic digestion with the adjustment of influent bypass rates was proposed to reduce the reactor temperature and the external carbon requirement. The biological treatment could discharge about 1,100 mg/L soluble COD and 50 mg/L soluble nitrogen, respectively. PMID:15137412

  15. Cleavage fracture properties of high strength steel weldments

    SciTech Connect

    Hughes, R.K.; Ritter, J.C.

    1996-12-31

    The qualification of consumables and welding of steels in critical naval applications, including submarine construction, is dependent upon the achievement of high levels of toughness at low temperature. The principal technique employed is the Charpy impact test at temperatures down to {minus}115 C ({minus}175 F). In the investigation described here, low temperature toughness properties were investigated by breaking notched specimens in slow four point bending and measuring the critical tensile stress for cleavage initiation. Multi-pass Flux Cored Arc (FCA) welds joining 690 MPa (100 ksi) yield strength, quenched and tempered steel were tested to identify cleavage fracture micromechanisms and to investigate the role of microstructural features in the cleavage fracture process. Cleavage fracture stress values in the range 2,018 to 2,381 MPa were recorded in weld metal when testing at sub-zero temperatures. Detailed examination of fracture surfaces by scanning electron microscope (SEM) revealed that weld metal inclusions play a critical role in acting as cleavage initiation sites. Changing welding position from downhand to vertical-up resulted in a small number of widely spaced inclusions approaching or exceeding 10 {micro}m in diameter but these were not observed to act as cleavage initiation sites. The cleavage fracture resistance of multi-pass Manual Metal Arc (MMA) welds which are currently under investigation is compared with FCA weldments.

  16. Titanium cholla : lightweight, high-strength structures for aerospace applications.

    SciTech Connect

    Atwood, Clinton J.; Voth, Thomas Eugene; Taggart, David G.; Gill, David Dennis; Robbins, Joshua H.; Dewhurst, Peter

    2007-10-01

    Aerospace designers seek lightweight, high-strength structures to lower launch weight while creating structures that are capable of withstanding launch loadings. Most 'light-weighting' is done through an expensive, time-consuming, iterative method requiring experience and a repeated design/test/redesign sequence until an adequate solution is obtained. Little successful work has been done in the application of generalized 3D optimization due to the difficulty of analytical solutions, the large computational requirements of computerized solutions, and the inability to manufacture many optimized structures with conventional machining processes. The Titanium Cholla LDRD team set out to create generalized 3D optimization routines, a set of analytically optimized 3D structures for testing the solutions, and a method of manufacturing these complex optimized structures. The team developed two new computer optimization solutions: Advanced Topological Optimization (ATO) and FlexFEM, an optimization package utilizing the eXtended Finite Element Method (XFEM) software for stress analysis. The team also developed several new analytically defined classes of optimized structures. Finally, the team developed a 3D capability for the Laser Engineered Net Shaping{trademark} (LENS{reg_sign}) additive manufacturing process including process planning for 3D optimized structures. This report gives individual examples as well as one generalized example showing the optimized solutions and an optimized metal part.

  17. Thermal Desorption Analysis of Hydrogen in High Strength Martensitic Steels

    NASA Astrophysics Data System (ADS)

    Enomoto, M.; Hirakami, D.; Tarui, T.

    2012-02-01

    Thermal desorption analyses (TDA) were conducted in high strength martensitic steels containing carbon from 0.33 to 1.0 mass pct, which were charged with hydrogen at 1223 K (950 °C) under hydrogen of one atmospheric pressure and quenched to room temperature. In 0.33C steel, which had the highest M s temperature, only one desorption peak was observed around 373 K (100 °C), whereas two peaks, one at a similar temperature and the other around and above 573 K (300 °C), were observed in the other steels, the height of the second peak increasing with carbon content. In 0.82C steel, both peaks disappeared during exposure at room temperature in 1 week, whereas the peak heights decreased gradually over 2 weeks in specimens electrolytically charged with hydrogen and aged for varying times at room temperature. From computer simulation, by means of the McNabb-Foster theory coupled with theories of carbon segregation, these peaks are likely to be due to trapping of hydrogen in the strain fields and cores of dislocations, and presumably to a lesser extent in prior austenite grain boundaries. The results also indicate that carbon atoms prevent and even expel hydrogen from trapping sites during quenching and aging in these steels.

  18. Fatigue crack retardation of high strength steel in saltwater

    SciTech Connect

    Tokaji, K.; Ando, Z.; Imai, T.; Kojima, T.

    1983-04-01

    A high strength steel was studied in 3 percent saltwater to investigate the effects of a corrosive environment and sheer thickness on fatigue crack propagation behavior following the application of a single tensile overload. Experiments were carried out under sinusoidally varying loads at a load ratio of 0 and frequency of 10 H /SUB z/ . A single tensile overload was found to cause delayed retardation, and the crack propagation rate at first increased, followed by fairly rapid decrease to a minimum value and then increased gradually to its steady-state value, just as it did in air. The overload affected zone size and the retardation cycles increased with decreasing sheet thickness, just as they did in air. However, the zone size and the cycles were larger in 3 percent saltwater than in air. Since the crack propagation rates through the overload affected zone were not affected by the test environment, the longer retardation cycles in 3 percent saltwater were attributed to an enlargement of the overload affected zone size. The crack propagation behavior following the application of a single tensile overload in 3 percent saltwater was well explained by the crack closure concept.

  19. Silphenylene elastomers have high thermal stability and tensile strength

    NASA Technical Reports Server (NTRS)

    1969-01-01

    Two polymeric silphenylene ethers, when cured by reactions with ethyl silicates and metal salts at room temperature, form elastomers having excellent thermal stability and tensile properties. The highest tensile strength obtained in a reinforced elastomer was 2800 psi.

  20. Polyimide films from vapor deposition: toward high strength, NIF capsules

    SciTech Connect

    Cook, R C; Hsieh, E J; Letts, S A; Roberts, C C; Saculla, M

    1998-10-16

    The focus of recent efforts at LLNL has been to demonstrate that vapor deposition processing is a suitable technique to form polyimide fnms with sufficient strength for current national ignition facility target specifications. Production of polyimide films with controlled stoichiometry was acccomplished by: 1) depositing a novel co-functional monomer and 2) matching the vapor pressure of each monomer in PMDA/ODA co-depositions. The sublimation and deposition rate for the monomers was determined over a range of temperatures. Polyimide films with thicknesses up to 30 p.m were fabricated. Composition, structure and strength were assessed using FTIR, SEM and biaxial burst testing. The best films had a tensile strength of approximately 100 MPa. A qualitative relationship between the stoichiometry and tensile strength of the film was demonstrated. Thin films ({approximately}3.5 {micro}m) were typically smooth with an rms of 1.5 nm.

  1. High-strength cellular ceramic composites with 3D microarchitecture

    PubMed Central

    Bauer, Jens; Hengsbach, Stefan; Tesari, Iwiza; Schwaiger, Ruth; Kraft, Oliver

    2014-01-01

    To enhance the strength-to-weight ratio of a material, one may try to either improve the strength or lower the density, or both. The lightest solid materials have a density in the range of 1,000 kg/m3; only cellular materials, such as technical foams, can reach considerably lower values. However, compared with corresponding bulk materials, their specific strength generally is significantly lower. Cellular topologies may be divided into bending- and stretching-dominated ones. Technical foams are structured randomly and behave in a bending-dominated way, which is less weight efficient, with respect to strength, than stretching-dominated behavior, such as in regular braced frameworks. Cancellous bone and other natural cellular solids have an optimized architecture. Their basic material is structured hierarchically and consists of nanometer-size elements, providing a benefit from size effects in the material strength. Designing cellular materials with a specific microarchitecture would allow one to exploit the structural advantages of stretching-dominated constructions as well as size-dependent strengthening effects. In this paper, we demonstrate that such materials may be fabricated. Applying 3D laser lithography, we produced and characterized micro-truss and -shell structures made from alumina–polymer composite. Size-dependent strengthening of alumina shells has been observed, particularly when applied with a characteristic thickness below 100 nm. The presented artificial cellular materials reach compressive strengths up to 280 MPa with densities well below 1,000 kg/m3. PMID:24550268

  2. High-Precision Pulse Generator

    NASA Technical Reports Server (NTRS)

    Katz, Richard; Kleyner, Igor

    2011-01-01

    A document discusses a pulse generator with subnanosecond resolution implemented with a low-cost field-programmable gate array (FPGA) at low power levels. The method used exploits the fast carry chains of certain FPGAs. Prototypes have been built and tested in both Actel AX and Xilinx Virtex 4 technologies. In-flight calibration or control can be performed by using a similar and related technique as a time interval measurement circuit by measuring a period of the stable oscillator, as the delays through the fast carry chains will vary as a result of manufacturing variances as well as the result of environmental conditions (voltage, aging, temperature, and radiation).

  3. Shear Bond Strength of Superficial, Intermediate and Deep Dentin In Vitro with Recent Generation Self-etching Primers and Single Nano Composite Resin

    PubMed Central

    Singh, Kulshrest; Naik, Rajaram; Hegde, Srinidhi; Damda, Aftab

    2015-01-01

    Background: This in vitro study is intended to compare the shear bond strength of recent self-etching primers to superficial, intermediate, and deep dentin levels. Materials and Methods: All teeth were sectioned at various levels and grouped randomly into two experimental groups and two control groups having three subgroups. The experimental groups consisted of two different dentin bonding system. The positive control group consisted of All Bond 2 and the negative control group was without the bonding agent. Finally, the specimens were subjected to shear bond strength study under Instron machine. The maximum shear bond strengths were noted at the time of fracture. The results were statistically analyzed. Results: Comparing the shear bond strength values, All Bond 2 (Group III) demonstrated fairly higher bond strength values at different levels of dentin. Generally comparing All Bond 2 with the other two experimental groups revealed highly significant statistical results. Conclusion: In the present investigation with the fourth generation, higher mean shear bond strength values were recorded compared with the self-etching primers. When intermediate dentin shear bond strength was compared with deep dentin shear bond strength statistically significant results were found with Clearfil Liner Bond 2V, All Bond 2 and the negative control. There was a statistically significant difference in shear bond strength values both with self-etching primers and control groups (fourth generation bonding system and without bonding system) at superficial, intermediate, and deep dentin. There was a significant fall in bond strength values as one reaches deeper levels of dentin from superficial to intermediate to deep. PMID:26225101

  4. Highly controllable and green reduction of graphene oxide to flexible graphene film with high strength

    SciTech Connect

    Wan, Wubo; Zhao, Zongbin; Hu, Han; Gogotsi, Yury; Qiu, Jieshan

    2013-11-15

    Graphical abstract: Highly controllable and green reduction of GO to chemical converted graphene (CCG) was achieved with sodium citrate as a facile reductant. Self-assembly of the as-made CCG sheets results in a flexible CCG film, of which the tensile strength strongly depends on the deoxygenation degree of graphene sheets. - Highlights: • Graphene was synthesized by an effective and environmentally friendly approach. • We introduced a facile X-ray diffraction analysis method to investigate the reduction process from graphene oxide to graphene. • Flexible graphene films were prepared by self-assembly of the graphene sheets. • The strength of the graphene films depends on the reduction degree of graphene. - Abstract: Graphene film with high strength was fabricated by the assembly of graphene sheets derived from graphene oxide (GO) in an effective and environmentally friendly approach. Highly controllable reduction of GO to chemical converted graphene (CCG) was achieved with sodium citrate as a facile reductant, in which the reduction process was monitored by XRD analysis and UV–vis absorption spectra. Self-assembly of the as-made CCG sheets results in a flexible CCG film. This method may open an avenue to the easy and scalable preparation of graphene film with high strength which has promising potentials in many fields where strong, flexible and electrically conductive films are highly demanded.

  5. High Schools: The Next Generation.

    ERIC Educational Resources Information Center

    DeJong, William S.; Vezdos, Tracy A.

    1993-01-01

    Interdisciplinary high schools are characterized by the decentralization of specialized areas and organization of space into modules that reinforce student communication as well as flexibility. Starting with an interdisciplinary cluster approach and then overlaying the departments aids the process. (MLF)

  6. Heavyweight cement concrete with high stability of strength parameters

    NASA Astrophysics Data System (ADS)

    Kudyakov, Konstantin; Nevsky, Andrey; Danke, Ilia; Kudyakov, Aleksandr; Kudyakov, Vitaly

    2016-01-01

    The present paper establishes regularities of basalt fibers distribution in movable cement concrete mixes under different conditions of their preparation and their selective introduction into mixer during the mixing process. The optimum content of basalt fibers was defined as 0.5% of the cement weight, which provides a uniform distribution of fibers in the concrete volume. It allows increasing compressive strength up to 51.2% and increasing tensile strength up to 28.8%. Micro-structural analysis identified new formations on the surface of basalt fibers, which indicates the good adhesion of hardened cement paste to the fibers. Stability of concrete strength parameters has significantly increased with introduction of basalt fibers into concrete mix.

  7. Geckolike high shear strength by carbon nanotube fiber adhesives

    NASA Astrophysics Data System (ADS)

    Maeno, Y.; Nakayama, Y.

    2009-01-01

    Carbon nanotube adhesives can adhere strongly to surfaces as a gecko does. The number of carbon nanotube layers is an important determinant of the contact area for adhesion. Balancing the catalyst ratio and buffer layer used for chemical vapor deposition processing controls the number of carbon nanotube layers and their distribution. The features of carbon nanotubes determine the shear strength of adhesion. Carbon nanotubes with a broad distribution of layers exhibit enhanced shear strength with equivalent adhesive capability to that of a natural Tokay Gecko (Gekko gecko)

  8. TRP 9904 - Constitutive Behavior of High Strength Multiphase Sheel Steel Under High Strain Rate Deformation

    SciTech Connect

    David Matlock; John Speer

    2005-03-31

    The focus of the research project was to systematically assess the strain rate dependence of strengthening mechanisms in new advanced high strength sheet steels. Data were obtained on specially designed and produced Duel Phase and TRIP steels and compared to the properties of automotive steels currently in use.

  9. High-pressure reactions and shear strength of serpentinized dunite.

    PubMed

    Sclar, C B; Carrison, L C; Rooney, T P; Riecker, R E

    1966-09-01

    The recently reported Pronounced decrease in shear strength of serpentine-bearing rocks at 30 to 40 kilobars in the temperature range 300 degrees to 520 degrees C may be attributed to the transformation of serpentine to a Pressure-dependent, 10-angstrom,2: 1 layer silicate plus brucite and periclase. This reaction increases density by about 8.5 percent. PMID:17754251

  10. THE SMALL HIGH SCHOOL--ITS STRENGTH AND LIMITATIONS.

    ERIC Educational Resources Information Center

    BOHRSON, RALPH G.

    THE CONTROVERSY REGARDING THE PROGRAM EFFECTIVENESS OF SMALL SCHOOLS HAS BEEN BASED ON NINE INVALID ASSUMPTIONS REGARDING THE NUMBER OF STUDENTS INVOLVED, PROBLEMS OF TEACHING, PROGRAM QUALITY AND TEACHING, SCHOOL REDISTRICTING, EDUCATIONAL FINANCE, CURRICULUM, LEADERSHIP ROLE, INHERENT STRENGTHS, AND QUALITY AS A FUNCTION OF NUMBERS. THE MAJOR…

  11. Growing the Seeds of Strength in High Risk Urban Neighborhoods.

    ERIC Educational Resources Information Center

    Saegert, Susan

    The lives of poor minority city residents demonstrate the diversity, multiple potentials, and vulnerability to external structures. In spite of the stereotypes of failure and the very real problems of the urban poor, there are many strengths among the so-called urban underclass and there are aspects of life that are successful and productive. In…

  12. High strength-high conductivity Cu--Fe composites produced by powder compaction/mechanical reduction

    DOEpatents

    Verhoeven, John D.; Spitzig, William A.; Gibson, Edwin D.; Anderson, Iver E.

    1991-08-27

    A particulate mixture of Cu and Fe is compacted and mechanically reduced to form an "in-situ" Cu-Fe composite having high strength and high conductivity. Compaction and mechanical reduction of the particulate mixture are carried out at a temperature and time at temperature selected to avoid dissolution of Fe into the Cu matrix particulates to a harmful extent that substantially degrades the conductivity of the Cu-Fe composite.

  13. High strength-high conductivity Cu-Fe composites produced by powder compaction/mechanical reduction

    DOEpatents

    Verhoeven, J.D.; Spitzig, W.A.; Gibson, E.D.; Anderson, I.E.

    1991-08-27

    A particulate mixture of Cu and Fe is compacted and mechanically reduced to form an ''in-situ'' Cu-Fe composite having high strength and high conductivity. Compaction and mechanical reduction of the particulate mixture are carried out at a temperature and time at temperature selected to avoid dissolution of Fe into the Cu matrix particulates to a harmful extent that substantially degrades the conductivity of the Cu-Fe composite. 5 figures.

  14. Photoconductive switching for high power microwave generation

    SciTech Connect

    Pocha, M.D.; Hofer, W.W.

    1990-10-01

    Photoconductive switching is a technology that is being increasingly applied to generation of high power microwaves. Two primary semiconductors used for these devices are silicon and gallium arsenide. Diamond is a promising future candidate material. This paper discusses the important material parameters and switching modes, critical issues for microwave generation, and future directions for this high power, photoconductive switching technology.

  15. High breakdown-strength composites from liquid silicone rubbers

    NASA Astrophysics Data System (ADS)

    Vudayagiri, Sindhu; Zakaria, Shamsul; Yu, Liyun; Sager Hassouneh, Suzan; Benslimane, Mohamed; Ladegaard Skov, Anne

    2014-10-01

    In this paper we investigate the performance of liquid silicone rubbers (LSRs) as dielectric elastomer transducers. Commonly used silicones in this application include room-temperature vulcanisable (RTV) silicone elastomers and composites thereof. Pure LSRs and their composites with commercially available fillers (an anatase TiO2, a core-shell TiO2-SiO2 and a CaCu3Ti4O12 filler) are evaluated with respect to dielectric permittivity, elasticity (Young’s modulus) and electrical breakdown strength. Film formation properties are also evaluated. The best-performing formulations are those with anatase TiO2 nanoparticles, where the highest relative dielectric permittivity of 5.6 is obtained, and with STX801, a core-shell morphology TiO2-SiO2 filler from Evonik, where the highest breakdown strength of 173 V μm-1 is obtained.

  16. High level white noise generator

    DOEpatents

    Borkowski, Casimer J.; Blalock, Theron V.

    1979-01-01

    A wide band, stable, random noise source with a high and well-defined output power spectral density is provided which may be used for accurate calibration of Johnson Noise Power Thermometers (JNPT) and other applications requiring a stable, wide band, well-defined noise power spectral density. The noise source is based on the fact that the open-circuit thermal noise voltage of a feedback resistor, connecting the output to the input of a special inverting amplifier, is available at the amplifier output from an equivalent low output impedance caused by the feedback mechanism. The noise power spectral density level at the noise source output is equivalent to the density of the open-circuit thermal noise or a 100 ohm resistor at a temperature of approximately 64,000 Kelvins. The noise source has an output power spectral density that is flat to within 0.1% (0.0043 db) in the frequency range of from 1 KHz to 100 KHz which brackets typical passbands of the signal-processing channels of JNPT's. Two embodiments, one of higher accuracy that is suitable for use as a standards instrument and another that is particularly adapted for ambient temperature operation, are illustrated in this application.

  17. Imploding Liner Material Strength Measurements at High-Strain and High Strain Rate

    SciTech Connect

    Bartsch, R.R.; Lee, H.; Holtkamp, D.; Wright, B.; Stokes, J.; Morgan, D.; Anderson, W.; Broste, W.

    1998-10-18

    Imploding, cylindrical liners provide a unique, shockless means of simultaneously accessing high strain and high-strain-rate for measurement of strength of materials in plastic flow. The radial convergence in the liner geometry results in the liner thickening as the circumference becomes smaller. Strains of up to {approximately}1.25 and strain rates of up to {approximately}10{sup 6} sec{sup -1} can be readily achieved in a material sample placed inside of an aluminum driver liner, using the Pegasus II capacitor bank. This provides yield strength data at conditions where none presently exists. The heating from work done against the yield strength is measured with multichannel pyrometry from infrared radiation emitted by the material sample. The temperature data as a function of liner position are unfolded to give the yield strength along the strain, strain-rate trajectory. Proper design of the liner and sample configuration ensures that the current diffused into the sample adds negligible heating. An important issue, in this type of temperature measurement, is shielding of the pickup optics from other sources of radiation. At strains greater than those achievable on Pegasus, e.g. the LANL Atlas facility, some materials may be heated all the way to melt by this process. Recent data on 6061-T6 Aluminum will be compared with an existing model for strain and strain-rate heating. The liner configuration and pyrometry diagnostic will also be discussed.

  18. High strength and high ductility behavior of 6061-T6 alloy after laser shock processing

    NASA Astrophysics Data System (ADS)

    Gencalp Irizalp, Simge; Saklakoglu, Nursen

    2016-02-01

    The plastic deformation behavior of 6061-T6 alloy which was subjected to severe plastic deformation (SPD) at high strain rates during laser shock processing (LSP) was researched. In LSP-treated materials, the near surface microstructural change was examined by TEM and fracture surfaces after tensile testing were examined by SEM. An increase in strength of metallic materials brings about the decrease in ductility. In this study, the results showed that LSP-treated 6061-T6 alloy exhibited both high strength and high ductility. TEM observation showed that stacking fault (SF) ribbon enlarged, deformation twins formed and twin boundary increased in LSP-treated 6061-T6 alloy. This observation was an indication of stacking fault energy (SFE) decrease. Work hardening capability was recovered after LSP impacts.

  19. Dynamical mass generation in QED with magnetic fields: Arbitrary field strength and coupling constant

    SciTech Connect

    Rojas, Eduardo; Ayala, Alejandro; Bashir, Adnan; Raya, Alfredo

    2008-05-01

    We study the dynamical generation of masses for fundamental fermions in quenched quantum electrodynamics, in the presence of magnetics fields of arbitrary strength, by solving the Schwinger-Dyson equation for the fermion self-energy in the rainbow approximation. We employ the Ritus eigenfunction formalism which provides a neat solution to the technical problem of summing over all Landau levels. It is well known that magnetic fields catalyze the generation of fermion mass m for arbitrarily small values of electromagnetic coupling {alpha}. For intense fields it is also well known that m{proportional_to}{radical}(eB). Our approach allows us to span all regimes of parameters {alpha} and eB. We find that m{proportional_to}{radical}(eB) provided {alpha} is small. However, when {alpha} increases beyond the critical value {alpha}{sub c} which marks the onslaught of dynamical fermion masses in vacuum, we find m{proportional_to}{lambda}, the cutoff required to regularize the ultraviolet divergences. Our method permits us to verify the results available in literature for the limiting cases of eB and {alpha}. We also point out the relevance of our work for possible physical applications.

  20. A novel electrospinning approach to fabricate high strength aqueous silk fibroin nanofibers.

    PubMed

    Singh, B N; Panda, N N; Pramanik, K

    2016-06-01

    The present paper describes a rapid method of producing concentrated aqueous regenerated Bombyx mori silk fibroin (RSF) solution by applying mild shearing under forced dehumidified air and generation of electrospun SF nanofibers from concentrated solution with high mechanical strength using free liquid surface electrospinning machine. The shear induced concentrating mechanism favoured the electrospinning process by enhancing the viscosity (>2.43Pas as onset for electrospinning) and decreasing the surface tension of the solution (40.1-37.7mN/m). Shearing reduced the β-turns and random coil molecular conformation and thereby, intensified the β-sheet content from 16.9% to 34% which is the minimum content needed to commence RSF nanofibers formation. Subsequently, electrospun nanofibrous mats were produced from different batches of concentrated SF solutions (15-21wt%). Among the concentrated RSF, 17wt% RSF solution was the most favourable concentration producing electrospun nanofibrous mat having lowest average fiber diameters of 183±55nm and good tensile strength. The mechanical strength of the nanofibrous sheet was further improved by cross-linking with 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride and N-hydroxysuccinimide (EDC+NHS) which might be due to enhancement of β-sheet content. These nanofibers exhibited 17.57±1.13MPa ultimate tensile strength, 12.48±1.46% tensile strain at break and 37.7% increase in root mean square surface roughness which is favourable feature for cell adhesion and neo-tissue formation. PMID:26905467

  1. High Strength and Wear Resistant Aluminum Alloy for High Temperature Applications

    NASA Technical Reports Server (NTRS)

    Lee, Jonathan A.; Munafo, Paul M. (Technical Monitor)

    2002-01-01

    In this paper, a new high strength and wear resistant aluminum cast alloy invented by NASA-MSFC for high temperature applications will be presented. Developed to meet U.S. automotive legislation requiring low-exhaust emission, the novel NASA 398 aluminum-silicon alloy offers dramatic improvement in tensile and fatigue strengths at elevated temperatures (500 F-800 F), enabling new pistons to utilize less material, which can lead to reducing part weight and cost as well as improving performance. NASA 398 alloy also offers greater wear resistance, surface hardness, dimensional stability, and lower thermal expansion compared to conventional aluminum alloys for several commercial and automotive applications. The new alloy can be produced economically using permanent steel molds from conventional gravity casting or sand casting. The technology was developed to stimulate the development of commercial aluminum casting products from NASA-developed technology by offering companies the opportunity to license this technology.

  2. Commercialization of NASA's High Strength Cast Aluminum Alloy for High Temperature Applications

    NASA Technical Reports Server (NTRS)

    Lee, Jonathan A.

    2003-01-01

    In this paper, the commercialization of a new high strength cast aluminum alloy, invented by NASA-Marshall Space Flight Center, for high temperature applications will be presented. Originally developed to meet U.S. automotive legislation requiring low- exhaust emission, the novel NASA aluminum alloy offers dramatic improvement in tensile and fatigue strengths at elevated temperatures (450 F-750 F), which can lead to reducing part weight and cost as well as improving performance for automotive engine applications. It is an ideal low cost material for cast components such as pistons, cylinder heads, cylinder liners, connecting rods, turbo chargers, impellers, actuators, brake calipers and rotors. NASA alloy also offers greater wear resistance, dimensional stability, and lower thermal expansion compared to conventional aluminum alloys, and the new alloy can be produced economically from sand, permanent mold and investment casting. Since 2001, this technology was licensed to several companies for automotive and marine internal combustion engines applications.

  3. High Shear Deformation to Produce High Strength and Energy Absorption in Mg Alloys

    SciTech Connect

    Joshi, Vineet V.; Jana, Saumyadeep; Li, Dongsheng; Garmestani, Hamid; Nyberg, Eric A.; Lavender, Curt A.

    2014-02-01

    Magnesium alloys have the potential to reduce the mass of transportation systems however to fully realize the benefits it must be usable in more applications including those that require higher strength and ductility. It has been known that fine grain size in Mg alloys leads to high strength and ductility. However, the challenge is how to achieve this optimal microstructure in a cost effective way. This work has shown that by using optimized high shear deformation and second phase particles of Mg2Si and MgxZnZry the energy absorption of the extrusions can exceed that of AA6061. The extrusion process under development described in this presentation appears to be scalable and cost effective. In addition to process development a novel modeling approach to understand the roles of strain and state-of-strain on particle fracture and grain size control has been developed

  4. Simple processing method for high-strength silicon carbide

    NASA Technical Reports Server (NTRS)

    Hurst, Janet B.; Dutta, Sunil

    1987-01-01

    Silicon carbide test bars were made by a simple wet-processing technique. The pressure casting method used the same equipment as conventional dry-pressing, but with a modified die. This casting technique was employed in order to produce test bars with improved strength and smaller fracture flaws than produced by dry-pressing. This was accomplished by eliminating pore clusters which were present in dry-pressed specimens and identified as a common source of failure in SiC MOR test bars.

  5. Stress corrosion in high-strength aluminum alloys

    NASA Technical Reports Server (NTRS)

    Dorward, R. C.; Hasse, K. R.

    1980-01-01

    Report describes results of stress-corrosion tests on aluminum alloys 7075, 7475, 7050, and 7049. Tests compare performance of original stress-corrosion-resistant (SCR) aluminum, 7075, with newer, higher-strength SCR alloys. Alloys 7050 and 7049 are found superior in short-transverse cross-corrosion resistance to older 7075 alloy; all alloys are subject to self-loading effect caused by wedging of corrosion products in cracks. Effect causes cracks to continue to grow, even at very-low externally applied loads.

  6. Advanced nickel base alloys for high strength, corrosion applications

    DOEpatents

    Flinn, J.E.

    1998-11-03

    Improved nickel-base alloys of enhanced strength and corrosion resistance, produced by atomization of an alloy melt under an inert gas atmosphere and of composition 0--20Fe, 10--30Cr, 2--12Mo, 6 max. Nb, 0.05--3 V, 0.08 max. Mn, 0.5 max. Si, less than 0.01 each of Al and Ti, less than 0.05 each of P and S, 0.01--0.08C, less than 0.2N, 0.1 max. 0, bal. Ni. 3 figs.

  7. Advanced nickel base alloys for high strength, corrosion applications

    DOEpatents

    Flinn, John E.

    1998-01-01

    Improved nickel-base alloys of enhanced strength and corrosion resistance, produced by atomization of an alloy melt under an inert gas atmosphere and of composition 0-20Fe, 10-30Cr, 2-12Mo, 6 max. Nb, 0.05-3 V, 0.08 max. Mn, 0.5 max. Si, less than 0.01 each of Al and Ti, less than 0.05 each of P and S, 0.01-0.08C, less than 0.2N, 0.1 max. 0, bal. Ni.

  8. A high voltage programmable ramp generator

    SciTech Connect

    Upadhyay, J.; Joshi, M. J.; Deshpande, P. P.; Sharma, M. L.; Navathe, C. P.

    2008-05-15

    In this paper, a ramp generator with programmable slope is presented. It consists of a high voltage step generator, followed by integrator. The capacitor and inductor in the integrator are designed such that they can be varied by a microcontroller. This circuit generates two bipolar ramps with fastest speed <1 ns and provides continuous speed variation from 6 to 30 ns for a ramp of 500 V. This is being developed as a part of automated streak camera for deflection of electron beam.

  9. Development of high toughness, high strength aluminide-bonded carbide ceramics

    SciTech Connect

    Becher, P.F.; Plucknett, K.P.; Tiegs, T.N.

    1997-04-01

    Cemented carbides are widely used in applications where resistance to abrasion and wear are important, particularly in combination with high strength and stiffness. In the present case, ductile aluminides have been used as a binder phase to fabricate dense carbide cermets by either sintering of mixed powders or a melt-infiltration sintering process. The choice of an aluminide binder was based on the exceptional high temperature strength and chemical stability exhibited by these alloys. For example, TiC-based composites with a Ni{sub 3}Al binder phase exhibit improved oxidation resistance, Young`s moduli > 375 GPa, high fracture strengths (> 1 GPa) that are retained to {ge} 900{degrees}C, and fracture toughness values of 10 to 15 MPa{radical}m, identical to that measured in commercial cobalt-bonded WC with the same test method. The thermal diffusivity values at 200{degrees}C for these composites are {approximately} 0.070 to 0.075 cm{sup 2}/s while the thermal expansion coefficients rise with Ni3Al content from {approximately} 8 to {approximately}11 x 10{sup {minus}6}/{degrees}C over the range of 8 to 40 vol. % Ni{sub 3}Al. The oxidation and acidic corrosion resistances are quite promising as well. Finally, these materials also exhibit good electrical conductivity allowing them to be sectioned and shaped by electrical discharge machining (EDM) processes.

  10. ETV Program Report: Big Fish Septage and High Strength Waste Water Treatment System

    EPA Science Inventory

    Verification testing of the Big Fish Environmental Septage and High Strength Wastewater Processing System for treatment of high-strength wastewater was conducted at the Big Fish facility in Charlevoix, Michigan. Testing was conducted over a 13-month period to address different c...

  11. Shear bond strength of seventh generation bonding agents on dentin of primary teeth--an in vitro study.

    PubMed

    Gonzalez, Geoffrey; Rich, Alfred P; Finkelman, Matthew D; Defuria, Catherine

    2012-01-01

    This controlled, randomized, in vitro study evaluated the shear bond strength of several seventh generation bonding agents on the dentin of primary teeth. Six different adhesives were used: Xeno IV, Clearfil S3 Bond, Adper Prompt-L-Pop, AdheSE One, Bond Force, and Optibond (control). Ninety primary teeth were prepared by wet grinding with a 320-grit silicon carbide paper on a polishing wheel running at 110 RPM. After 24 hours of storage in water, shear bond strengths of each group were determined. The mean shear bond strength of the tested adhesive systems to primary dentin was 12.27 MPa. One-way ANOVA testing showed a statistically significant difference between adhesive products (P < 0.001). Tukey HSD post hoc tests were used to assess which means were significantly different from one another. There was no statistically significant difference between the fifth generation adhesive system (Optibond) and the two seventh generation systems (Xeno IV and Bond Force), with Optibond exhibiting a lower mean shear bond strength compared to Bond Force. Within the limitations of this study, there is a significant difference between seventh generation bonding materials. Bond Force and Optibond appear to exhibit higher shear bond strengths than the other products. PMID:22313979

  12. Study to determine and analyze the strength of high modulus glass in epoxy-matrix composites

    NASA Technical Reports Server (NTRS)

    Bacon, J. F.

    1974-01-01

    Glass composition research was conducted to produce a high modulus, high strength beryllium-free glass fiber. This program was built on the previous research for developing high modulus, high strength glass fibers which had a 5 weight percent beryllia content. The fibers resulting from the composition program were then used to produce fiber reinforced-epoxy resin composites which were compared with composites reinforced by commercial high modulus glass fibers, Thornel S graphite fiber, and hybrids where the external quarters were reinforced with Thornel S graphite fiber and the interior half with glass fiber as well as the reverse hybrid. The composites were given tensile strength, compressive strength, short-beam shear strength, creep and fatigue tests. Comments are included on the significance of the test data.

  13. High-harmonic generation in cavitated plasmas

    SciTech Connect

    Schroeder, C. B.; Esarey, E.; Comier-Michel, E.; Leemans, W. P.

    2008-05-15

    A method is proposed for producing coherent x-rays via high-harmonic generation using ultraintense lasers interacting with highly stripped ions in cavitated plasmas. This method relies on plasma cavitation by the wake of an intense drive beam (laser or electron beam) to produce an ion cavity. An ultrashort pulse laser propagating in the plasma-electron-free ion cavity generates laser harmonics. The longitudinal electron motion, which inhibits high-harmonic generation at high laser intensities, can be suppressed by the space-charge field in the ion cavity or by using a counterpropagating laser pulse. Periodic suppression of the longitudinal electron motion may also be used to quasi-phase-match. This method enables harmonic generation to be extended to the sub-A regime.

  14. High Energy Output Marx Generator Design

    SciTech Connect

    Monty Lehmann

    2011-07-01

    High Energy Output Marx Generator Design a design of a six stage Marx generator that has a unipolar pulse waveform of 200 kA in a 50×500 microsecond waveform is presented. The difficulties encountered in designing the components to withstand the temperatures and pressures generated during the output pulse are discussed. The unique methods and materials used to successfully overcome these problems are given. The steps necessary to increase the current output of this Marx generator design to the meg-ampere region or higher are specified.

  15. Shock compression and release in high-strength ceramics

    SciTech Connect

    Kipp, M E; Grady, D E

    1989-08-01

    A preliminary investigation of shock compression and release properties has been performed on four ceramics: silicon carbide, titanium diboride, boron carbide and zirconium dioxide. Eight planar impact experiments using thin discs of similar ceramic as impactor and target have been completed. The particle velocity history at the interface between the back of the target ceramic and a lithium fluoride window material was acquired with a laser velocity interferometer (VISAR). These wave profiles indicate that each of these materials responds in a unique way to shock loading. Peak impact stresses in these experiments range between 20 and 50 GPa, leading to pronounced permanent deformation behavior of these materials. Dynamic compression and release stress-strain behavior of the ceramics, formulated with numerical iteration methods, is compared with compressive strength properties determined from the experimental data. The current experiments provide data for these ceramic materials which can be used to evaluate computational material models in wave propagation codes. 23 refs., 25 figs., 4 tabs.

  16. Investigating strength of materials at very high strain rates using magnetically driven expanding cylinders

    NASA Astrophysics Data System (ADS)

    Lovinger, Zev; Nemirovsky, Ron; Avriel, Eyal; Dorogoy, Avraham; Ashuach, Yehezkel; Rittel, Daniel

    2015-09-01

    Dynamic characterization of strength properties is done, in common practice by the means of a Split-Hopkinson Pressure Bar (also named Kolsky-Bar) apparatus. In such systems, strain rates are limited up to ˜ 5 ṡ 103 sec-1. For higher strain rates, the strain rate hardening is assumed to be the same as that measured at lower rates, with no direct measurement to validate the assumptions used for this extrapolation. In this work we are using a pulsed current generator (PCG) to create electro-magnetic (EM) driving forces on expanding cylinders. Most standard techniques for creating EM driving forces on cylinders or rings, as reported in the literature, reach strain rates of 1e3-1e4. Using our PCG, characterized by a fast rise time, we reach strain rates of ˜1e5, thus paving the way to a standard technique to measure strength at very high strain rates. To establish the experimental technique, we conducted a numerical study of the expanding cylinder set up using 2D hydrodynamic simulations to reach the desired high strain rates.

  17. High-zirconium bulk metallic glasses with high strength and large ductility

    NASA Astrophysics Data System (ADS)

    Yang, YaoWei; Hua, NengBin; Li, Ran; Pang, ShuJie; Zhang, Tao

    2013-03-01

    In this paper, high-zirconium Zr66+2 x Al9- x (Ni1/3Cu2/3)25- x ( x=0,1,2 at.%) bulk metallic glasses with high strength and large ductility were fabricated by copper mould casting. The effects of zirconium content on the glass-forming ability (GFA), thermal properties and mechanical properties were investigated using X-ray diffractometer (XRD), differential scanning calorimeter (DSC), and mechanical testing system in compressive and three-point bending modes, respectively. The high-zirconium BMGs show the critical diameters of 3-5 mm, the supercooled liquid region ranging from 70 K to 99 K, and the yield strength of over 1700 MPa. The Zr70Al7(Ni1/3Cu2/3)23 BMG exhibits a large compressive plastic strain up to 21% and a high notch toughness value of 60.6 MPa m1/2. The increase in Zr content results in the decrease in GFA and thermostability, and in the improvement of plasticity under compressive and three-point bending conditions. The superior plasticity of high-zirconium BMGs is attributed to their high Poisson's ratio and small elastic modulus ratio µ/ B.

  18. Effect of microstructure on static and dynamic mechanical properties of high strength steels

    NASA Astrophysics Data System (ADS)

    Qu, Jinbo

    The high speed deformation behavior of a commercially available dual phase (DP) steel was studied by means of split Hopkinson bar apparatus in shear punch (25m/s) and tension (1000s-1) modes with an emphasis on the influence of microstructure. The cold rolled sheet material was subjected to a variety of heat treatment conditions to produce several different microstructures, namely ferrite plus pearlite, ferrite plus bainite and/or acicular ferrite, ferrite plus bainite and martensite, and ferrite plus different fractions of martensite. Static properties (0.01mm/s for shear punch and 0.001s -1 for tension) of all the microstructures were also measured by an MTS hydraulic machine and compared to the dynamic properties. The effects of low temperature tempering and bake hardening were investigated for some ferrite plus martensite microstructures. In addition, two other materials, composition designed as high strength low alloy (HSLA) steel and transformation induced plasticity (TRIP) steel, were heat treated and tested to study the effect of alloy chemistry on the microstructure and property relationship. A strong effect of microstructure on both static and dynamic properties and on the relationship between static and dynamic properties was observed. According to the variation of dynamic factor with static strength, three groups of microstructures with three distinct behaviors were identified, i.e. classic dual phase (ferrite plus less than 50% martensite), martensite-matrix dual phase (ferrite plus more than 50% martensite), and non-dual phase (ferrite plus non-martensite). Under the same static strength level, the dual phase microstructure was found to absorb more dynamic energy than other microstructures. It was also observed that the general dependence of microstructure on static and dynamic property relationship was not strongly influenced by chemical composition, except the ferrite plus martensite microstructures generated by the TRIP chemistry, which exhibited

  19. Creep Strength of Dissimilar Welded Joints Using High B-9Cr Steel for Advanced USC Boiler

    NASA Astrophysics Data System (ADS)

    Tabuchi, Masaaki; Hongo, Hiromichi; Abe, Fujio

    2014-10-01

    The commercialization of a 973 K (700 °C) class pulverized coal power system, advanced ultra-supercritical (A-USC) pressure power generation, is the target of an ongoing research project initiated in Japan in 2008. In the A-USC boiler, Ni or Ni-Fe base alloys are used for high-temperature parts at 923 K to 973 K (650 °C to 700 °C), and advanced high-Cr ferritic steels are planned to be used at temperatures lower than 923 K (650 °C). In the dissimilar welds between Ni base alloys and high-Cr ferritic steels, Type IV failure in the heat-affected zone (HAZ) is a concern. Thus, the high B-9Cr steel developed at the National Institute for Materials Science, which has improved creep strength in weldments, is a candidate material for the Japanese A-USC boiler. In the present study, creep tests were conducted on the dissimilar welded joints between Ni base alloys and high B-9Cr steels. Microstructures and creep damage in the dissimilar welded joints were investigated. In the HAZ of the high B-9Cr steels, fine-grained microstructures were not formed and the grain size of the base metal was retained. Consequently, the creep rupture life of the dissimilar welded joints using high B-9Cr steel was 5 to 10 times longer than that of the conventional 9Cr steel welded joints at 923 K (650 °C).

  20. Laser-Assisted Sheet Metal Working of High Strength Steels in Serial Production

    NASA Astrophysics Data System (ADS)

    Brecher, Christian; Emonts, Michael; Eckert, Markus

    Within the sheet metal working industry the demand for thinner sheet materials with very high strength is growing due to the increasing need to save energy and a responsible use of natural resources. The high strength and the low ductility restricts using state of art technology to sheer, bend, emboss or deep draw parts with the needed complexity and quality. The Fraunhofer IPT developed a combination of laser-assisted preheating and conventional punching to a new hybrid technology which allows to shear, bend, emboss and draw high strength materials with a high quality and complexity in a serial production.

  1. Microstructural effects on the stress corrosion cracking behavior of medium and high strength steels

    NASA Astrophysics Data System (ADS)

    Kerr, R.; Solana, F.; Bernstein, I. M.; Thompson, A. W.

    1987-01-01

    The effects of variations in microstructure and strength level on the stress corrosion cracking susceptibility of three medium to high strength steels, H13, 300M, and HY-130, in 3.5 pct NaCl have been systematically studied. Superimposed on the expected inverse dependence of KISCC on yield strength was more than an order of magnitude reduction in crack growth rate, with no strength penalty. These results have been analyzed in terms of the possible relative roles of different microstructural features, in particular retained austenite, whose detailed behavior is the subject of a companion paper.

  2. Microstructural effects on the stress corrosion cracking behavior of medium and high strength steels

    NASA Astrophysics Data System (ADS)

    Kerr, R.; Solana, F.; Bernstein, I. M.; Thompson, A. W.

    1991-01-01

    The effects of variations in microstructure and strength level on the stress corrosion cracking susceptibility of three medium to high strength steels, H13, 300M, and HY-130, in 3.5 pct NaCl have been systematically studied. Superimposed on the expected inverse dependence of KISCC on yield strength was more than an order of magnitude reduction in crack growth rate, with no strength penalty. These results have been analyzed in terms of the possible relative roles of different microstructural features, in particular retained austenite, whose detailed behavior is the subject of a companion paper.

  3. Hot isostatically pressed manufacture of high strength MERL 76 disk and seal shapes

    NASA Technical Reports Server (NTRS)

    Eng, R. D.; Evans, D. J.

    1982-01-01

    The feasibility of using MERL 76, an advanced high strength direct hot isostatic pressed powder metallurgy superalloy, as a full scale component in a high technology, long life, commercial turbine engine were demonstrated. The component was a JT9D first stage turbine disk. The JT9D disk rim temperature capability was increased by at least 22 C and the weight of JT9D high pressure turbine rotating components was reduced by at least 35 pounds by replacement of forged Superwaspaloy components with hot isostatic pressed (HIP) MERL 76 components. The process control plan and acceptance criteria for manufacture of MERL 76 HIP consolidated components were generated. Disk components were manufactured for spin/burst rig test, experimental engine tests, and design data generation, which established lower design properties including tensile, stress-rupture, 0.2% creep and notched (Kt = 2.5) low cycle fatigue properties, Sonntag, fatigue crack propagation, and low cycle fatigue crack threshold data. Direct HIP MERL 76, when compared to conventionally forged Superwaspaloy, is demonstrated to be superior in mechanical properties, increased rim temperature capability, reduced component weight, and reduced material cost by at least 30% based on 1980 costs.

  4. Fabrication of Carbon Nanotube High-Frequency Nanoelectronic Biosensor for Sensing in High Ionic Strength Solutions

    PubMed Central

    Kulkarni, Girish S.; Zhong, Zhaohui

    2013-01-01

    The unique electronic properties and high surface-to-volume ratios of single-walled carbon nanotubes (SWNT) and semiconductor nanowires (NW) 1-4 make them good candidates for high sensitivity biosensors. When a charged molecule binds to such a sensor surface, it alters the carrier density5 in the sensor, resulting in changes in its DC conductance. However, in an ionic solution a charged surface also attracts counter-ions from the solution, forming an electrical double layer (EDL). This EDL effectively screens off the charge, and in physiologically relevant conditions ~100 millimolar (mM), the characteristic charge screening length (Debye length) is less than a nanometer (nm). Thus, in high ionic strength solutions, charge based (DC) detection is fundamentally impeded6-8. We overcome charge screening effects by detecting molecular dipoles rather than charges at high frequency, by operating carbon nanotube field effect transistors as high frequency mixers9-11. At high frequencies, the AC drive force can no longer overcome the solution drag and the ions in solution do not have sufficient time to form the EDL. Further, frequency mixing technique allows us to operate at frequencies high enough to overcome ionic screening, and yet detect the sensing signals at lower frequencies11-12. Also, the high transconductance of SWNT transistors provides an internal gain for the sensing signal, which obviates the need for external signal amplifier. Here, we describe the protocol to (a) fabricate SWNT transistors, (b) functionalize biomolecules to the nanotube13, (c) design and stamp a poly-dimethylsiloxane (PDMS) micro-fluidic chamber14 onto the device, and (d) carry out high frequency sensing in different ionic strength solutions11. PMID:23912795

  5. Fabrication of carbon nanotube high-frequency nanoelectronic biosensor for sensing in high ionic strength solutions.

    PubMed

    Kulkarni, Girish S; Zhong, Zhaohui

    2013-01-01

    The unique electronic properties and high surface-to-volume ratios of single-walled carbon nanotubes (SWNT) and semiconductor nanowires (NW) make them good candidates for high sensitivity biosensors. When a charged molecule binds to such a sensor surface, it alters the carrier density in the sensor, resulting in changes in its DC conductance. However, in an ionic solution a charged surface also attracts counter-ions from the solution, forming an electrical double layer (EDL). This EDL effectively screens off the charge, and in physiologically relevant conditions ~100 millimolar (mM), the characteristic charge screening length (Debye length) is less than a nanometer (nm). Thus, in high ionic strength solutions, charge based (DC) detection is fundamentally impeded. We overcome charge screening effects by detecting molecular dipoles rather than charges at high frequency, by operating carbon nanotube field effect transistors as high frequency mixers. At high frequencies, the AC drive force can no longer overcome the solution drag and the ions in solution do not have sufficient time to form the EDL. Further, frequency mixing technique allows us to operate at frequencies high enough to overcome ionic screening, and yet detect the sensing signals at lower frequencies. Also, the high transconductance of SWNT transistors provides an internal gain for the sensing signal, which obviates the need for external signal amplifier. Here, we describe the protocol to (a) fabricate SWNT transistors, (b) functionalize biomolecules to the nanotube, (c) design and stamp a poly-dimethylsiloxane (PDMS) micro-fluidic chamber onto the device, and (d) carry out high frequency sensing in different ionic strength solutions. PMID:23912795

  6. Surrogate Modeling of High-Fidelity Fracture Simulations for Real-Time Residual Strength Predictions

    NASA Technical Reports Server (NTRS)

    Spear, Ashley D.; Priest, Amanda R.; Veilleux, Michael G.; Ingraffea, Anthony R.; Hochhalter, Jacob D.

    2011-01-01

    A surrogate model methodology is described for predicting in real time the residual strength of flight structures with discrete-source damage. Starting with design of experiment, an artificial neural network is developed that takes as input discrete-source damage parameters and outputs a prediction of the structural residual strength. Target residual strength values used to train the artificial neural network are derived from 3D finite element-based fracture simulations. A residual strength test of a metallic, integrally-stiffened panel is simulated to show that crack growth and residual strength are determined more accurately in discrete-source damage cases by using an elastic-plastic fracture framework rather than a linear-elastic fracture mechanics-based method. Improving accuracy of the residual strength training data would, in turn, improve accuracy of the surrogate model. When combined, the surrogate model methodology and high-fidelity fracture simulation framework provide useful tools for adaptive flight technology.

  7. Gradient twinned 304 stainless steels for high strength and high ductility

    DOE PAGESBeta

    Chen, Aiying; Liu, Jiabin; Wang, Hongtao; Lu, Jian; Wang, Y. Morris

    2016-04-23

    Gradient materials often have attractive mechanical properties that outperform uniform microstructure counterparts. It remains a difficult task to investigate and compare the performance of various gradient microstructures due to the difficulty of fabrication, the wide range of length scales involved, and their respective volume percentage variations. We have investigated four types of gradient microstructures in 304 stainless steels that utilize submicrotwins, nanotwins, nanocrystalline-, ultrafine- and coarse-grains as building blocks. Tensile tests reveal that the gradient microstructure consisting of submicrotwins and nanotwins has a persistent and stable work hardening rate and yields an impressive combination of high strength and high ductility,more » leading to a toughness that is nearly 50% higher than that of the coarse-grained counterpart. Ex- and in-situ transmission electron microscopy indicates that nanoscale and submicroscale twins help to suppress and limit martensitic phase transformation via the confinement of martensite within the twin lamellar. Twinning and detwinning remain active during tensile deformation and contribute to the work hardening behavior. We discuss the advantageous properties of using submicrotwins as the main load carrier and nanotwins as the strengthening layers over those coarse and nanocrystalline grains. Furthermore, our work uncovers a new gradient design strategy to help metals and alloys achieve high strength and high ductility.« less

  8. Production of small diameter high-temperature-strength refractory metal wires

    NASA Technical Reports Server (NTRS)

    Petrasek, D. W.; Signorelli, R. A.; King, G. W.

    1973-01-01

    Special thermomechanical techniques (schedules) have been developed to produce small diameter wire from three refractory metal alloys: colombian base alloy, tantalum base alloy, and tungsten base alloy. High strengths of these wires indicate their potential for contributing increased strength to metallic composites.

  9. Yearly Changes in the Body Composition and Muscular Strength of High School Wrestlers.

    ERIC Educational Resources Information Center

    Housh, Terry J.; And Others

    1988-01-01

    Changes in body composition as well as absolute and relative isokinetic forearm flexion and extension strength of high school wrestlers were studied. Increase in weight and improved wrestling performance were found to be, in part, a function of yearly changes in body composition and muscular strength. (JD)

  10. Conducting High Cycle Fatigue Strength Step Tests on Gamma TiAl

    NASA Technical Reports Server (NTRS)

    Lerch, Brad; Draper, Sue; Pereira, J. Mike

    2002-01-01

    High cycle fatigue strength testing of gamma TiAl by the step test method is investigated. A design of experiments was implemented to determine if the coaxing effect occurred during testing. Since coaxing was not observed, step testing was deemed a suitable method to define the fatigue strength at 106 cycles.

  11. High speed, high strength microwelding of Si/glass using ps-laser pulses.

    PubMed

    Miyamoto, Isamu; Okamoto, Yasuhiro; Hansen, Assi; Vihinen, Joma; Amberla, Tiina; Kangastupa, Jarno

    2015-02-01

    A novel microwelding procedure to join Si-to-glass using ps-laser pulses with high repetition rates is presented. The procedure provides weld joint with mechanical strength as high as 85 MPa and 45 MPa in sample pairs of Si/aluminosilicate (Si/SW-Y) and Si/borosilicate (Si/Borofloat 33), respectively, which are higher than anodic bonding, at high spatial resolution (< 20 µm) and very high throughput without pre- and post-heating. Laser-matter interaction analysis indicates that excellent weld joint of Si/glass is obtained by avoiding violent evaporation of Si substrate using ps-laser pulses. Laser welded Si/glass samples can be singulated along the weld lines by standard blade dicer without defects, demonstrating welding by ps-laser pulses is applicable to wafer-level packaging. PMID:25836199

  12. Enhanced long-term strength and durability of shotcrete with high-strength C{sub 12}A{sub 7} mineral-based accelerator

    SciTech Connect

    Won, Jong-Pil Hwang, Un-Jong; Lee, Su-Jin

    2015-10-15

    This study evaluated the performance of shotcrete using high strength C{sub 12}A{sub 7} mineral-based accelerator that has been developed to improve the durability and long-term strength. Rebound, compressive strength and flexural strength were tested in the field. Test result showed that existing C{sub 12}A{sub 7} mineral-based accelerator exhibits better early strength than the high-strength C{sub 12}A{sub 7} mineral-based accelerator until the early age, but high-strength C{sub 12}A{sub 7} mineral-based accelerator shows about 29% higher at the long-term age of 28 days. Microstructural analysis such as scanning electron microscope (SEM), X-ray diffraction (XRD) and nitrogen adsorption method was evaluated to analyze long-term strength development mechanism of high strength C{sub 12}A{sub 7} mineral-based accelerator. As analysis result, it had more dense structure due to the reaction product by adding material that used to enhanced strength. It had better resistance performance in chloride ion penetration, freezing–thawing and carbonation than shotcrete that used existing C{sub 12}A{sub 7} mineral-based accelerator.

  13. Implementation of tetra-poly(ethylene glycol) hydrogel with high mechanical strength into microfluidic device technology

    PubMed Central

    Takehara, Hiroaki; Nagaoka, Akira; Noguchi, Jun; Akagi, Takanori; Sakai, Takamasa; Chung, Ung-il; Kasai, Haruo; Ichiki, Takanori

    2013-01-01

    Hydrogels have several excellent characteristics suitable for biomedical use such as softness, biological inertness and solute permeability. Hence, integrating hydrogels into microfluidic devices is a promising approach for providing additional functions such as biocompatibility and porosity, to microfluidic devices. However, the poor mechanical strength of hydrogels has severely limited device design and fabrication. A tetra-poly(ethylene glycol) (tetra-PEG) hydrogel synthesized recently has high mechanical strength and is expected to overcome such a limitation. In this research, we have comprehensively studied the implementation of tetra-PEG gel into microfluidic device technology. First, the fabrication of tetra-PEG gel/PDMS hybrid microchannels was established by developing a simple and robust bonding technique. Second, some fundamental features of tetra-PEG gel/PDMS hybrid microchannels, particularly fluid flow and mass transfer, were studied. Finally, to demonstrate the unique application of tetra-PEG-gel-integrated microfluidic devices, the generation of patterned chemical modulation with the maximum concentration gradient: 10% per 20 μm in a hydrogel was performed. The techniques developed in this study are expected to provide fundamental and beneficial methods of developing various microfluidic devices for life science and biomedical applications. PMID:24404072

  14. Supramolecular gels with high strength by tuning of calix[4]arene-derived networks

    PubMed Central

    Lee, Ji Ha; Park, Jaehyeon; Park, Jin-Woo; Ahn, Hyo-Jun; Jaworski, Justyn; Jung, Jong Hwa

    2015-01-01

    Supramolecular gels comprised of low-molecular-weight gelators are generally regarded as mechanically weak and unable to support formation of free-standing structures, hence, their practical use with applied loads has been limited. Here, we reveal a technique for in situ generation of high tensile strength supramolecular hydrogels derived from low-molecular-weight gelators. By controlling the concentration of hydrochloric acid during hydrazone formation between calix-[4]arene-based gelator precursors, we tune the mechanical and ductile properties of the resulting gel. Organogels formed without hydrochloric acid exhibit impressive tensile strengths, higher than 40 MPa, which is the strongest among self-assembled gels. Hydrogels, prepared by solvent exchange of organogels in water, show 7,000- to 10,000-fold enhanced mechanical properties because of further hydrazone formation. This method of molding also allows the gels to retain shape after processing, and furthermore, we find organogels when prepared as gel electrolytes for lithium battery applications to have good ionic conductivity. PMID:25799459

  15. Effect of nanostructured composite powders on the structure and strength properties of the high-temperature inconel 718 alloy

    NASA Astrophysics Data System (ADS)

    Cherepanov, A. N.; Ovcharenko, V. E.

    2015-12-01

    The experimental results of the effect of powder nanomodifiers of refractory compounds on the strength properties, the macro- and microstructure of the high-temperature Inconel 718 alloy have been presented. It has been shown that the introduction of powder modifiers into the melt leads to a decrease in the average grain size by a factor of 1.5-2 in the alloy. The long-term tensile strength of the alloy at 650°C increases 1.5-2 times, and the number of cycles at 482°C before fracture grows by more than three times. The effect of nanoparticles on the grain structure and strength properties of the alloy is due to an increase in the number of generated crystallization centers and the formation of nanoparticle clusters of refractory compounds at boundaries and junctions in the formed grain structure, which hinder the development of recrystallization processes in the alloy.

  16. Cup-Drawing Behavior of High-Strength Steel Sheets Containing Different Volume Fractions of Martensite

    SciTech Connect

    Choi, Shi-Hoon; Kim, Dae-Wan; Yang, Hoe-Seok; Han, Seong-Ho; Yoon, Jeong Whan

    2010-06-15

    Planar anisotropy and cup-drawing behavior were investigated for high-strength steel sheets containing different volume fractions of martensite. Macrotexture analysis using XRD was conducted to capture the effect of crystallographic orientation on the planar anisotropy of high-strength steel sheets. A phenomenological yield function, Yld96, which accounts for the anisotropy of yield stress and r-values, was implemented into ABAQUS using the user subroutine UMAT. Cup drawing of high-strength steel sheets was simulated using the FEM code. The profiles of earing and thickness strain were compared with the experimentally measured results.

  17. Cup-Drawing Behavior of High-Strength Steel Sheets Containing Different Volume Fractions of Martensite

    NASA Astrophysics Data System (ADS)

    Choi, Shi-Hoon; Kim, Dae-Wan; Yang, Hoe-Seok; Han, Seong-Ho; Yoon, Jeong Whan

    2010-06-01

    Planar anisotropy and cup-drawing behavior were investigated for high-strength steel sheets containing different volume fractions of martensite. Macrotexture analysis using XRD was conducted to capture the effect of crystallographic orientation on the planar anisotropy of high-strength steel sheets. A phenomenological yield function, Yld96, which accounts for the anisotropy of yield stress and r-values, was implemented into ABAQUS using the user subroutine UMAT. Cup drawing of high-strength steel sheets was simulated using the FEM code. The profiles of earing and thickness strain were compared with the experimentally measured results.

  18. Spike timing-dependent serotonergic neuromodulation of synaptic strength intrinsic to a central pattern generator circuit.

    PubMed

    Sakurai, Akira; Katz, Paul S

    2003-11-26

    Neuromodulation is often thought to have a static, gain-setting function in neural circuits. Here we report a counter example: the neuromodulatory effect of a serotonergic neuron is dependent on the interval between its spikes and those of the neuron being modulated. The serotonergic dorsal swim interneurons (DSIs) are members of the escape swim central pattern generator (CPG) in the mollusk Tritonia diomedea. DSI spike trains heterosynaptically enhanced synaptic potentials evoked by another CPG neuron, ventral swim interneuron B (VSI-B), when VSI-B action potentials occurred within 10 sec of a DSI spike train; however, if VSI-B was stimulated 20-120 sec after DSI, then the amplitude of VSI-B synaptic potentials decreased. Consistent with this, VSI-B-evoked synaptic currents exhibited a temporally biphasic and bidirectional change in amplitude after DSI stimulation. Both the DSI-evoked enhancement and decrement were occluded by serotonin and blocked by the serotonin receptor antagonist methysergide, suggesting that both phases are mediated by serotonin. In most preparations, however, bath-applied serotonin caused only a sustained enhancement of VSI-B synaptic strength. The heterosynaptic modulation interacted with short-term homosynaptic plasticity: DSI-evoked depression was offset by VSI-B homosynaptic facilitation. This caused a complicated temporal pattern of neuromodulation when DSI and VSI-B were stimulated to fire in alternating bursts to mimic the natural motor pattern: DSI strongly enhanced summated VSI-B synaptic potentials and suppressed single synaptic potentials after the cessation of the artificial motor pattern. Thus, spike timing-dependent serotonergic neuromodulatory actions can impart temporal information that may be relevant to the operation of the CPG. PMID:14645466

  19. Unravel the key genes potentially related to high strength of cotton fiber by comparative phenotypic and genomic analyses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The demand of high strength of cotton fibers has been increased dramatically with the advent of modern high speed spinning technology for producing yarn. Bundle fiber strength is affected by fiber-to-fiber interactions in addition to the individual fiber strength. The bundle fiber strength is not al...

  20. High-lying excited states in Gamow Teller strength and their roles in neutrino reactions

    NASA Astrophysics Data System (ADS)

    Cheoun, Myung-Ki; Ha, Eunja; Kajino, Toshitaka

    2012-10-01

    The Gamow Teller (GT) transition strengths deduced from charge exchange reactions (CEXRs) are very helpful for understanding the nuclear reaction induced by neutrinos, in particular, by the solar neutrino. For further study of supernovae (SNe) neutrinos in the cosmos, one needs to study high-lying GT states around a few tens of MeV region as well as other multipole transitions because of the high energy tail in the neutrino spectra emitted from the neutrino sphere. In this report, we address the importance of the high-lying GT excited states, whose data now become available from various CEXR experiments. For example, GT(± strengths up to 70MeV are successfully extracted by 90Zr( n, p) and 90Zr( p, n) reactions. Our discussions are extended to investigate roles of the high-lying states beyond a few low-lying states known in the old experiment on the reaction induced by SNe neutrinos particularly on 40Ar target. The nucleus was originally exploited to identify the solar neutrino emitted from 8B produced in the pp-chains on the Sun, and now lots of applications for more energetic neutrino detection are under progress. The expected large difference between the cross-sections of νe^{} and bar{{ν}}e^{} reactions on 40Ar , whose differences were anticipated because of the large Q-value in the bar{{ν}}e^{} reaction, is significantly diminished compared to previous results. Our calculations are carried out by the Quasi-particle Random Phase Approximation (QRPA), which takes the neutron-proton pairing into account to the standard proton-neutron QRPA (pnQRPA) where only proton-proton and neutron-neutron pairing correlations are considered.

  1. Evaluation of high strength, high conductivity CuNiBe alloys for fusion energy applications

    NASA Astrophysics Data System (ADS)

    Zinkle, S. J.

    2014-06-01

    The unirradiated tensile properties for several different heats and thermomechanical treatment conditions of precipitation strengthened Hycon 3HP™ CuNiBe (Cu-2%Ni-0.35%Be in wt.%) have been measured over the temperature range of 20-500 °C for longitudinal and long transverse orientations. The room temperature electrical conductivity has also been measured for several heats, and the precipitate microstructure was characterized using transmission electron microscopy. The CuNiBe alloys exhibit very good combination of strength and conductivity at room temperature, with yield strengths of 630-725 MPa and electrical conductivities of 65-72% International Annealed Copper Standard (IACS). The strength remained relatively high at all test temperatures, with yield strengths of 420-520 MPa at 500 °C. However, low levels of ductility (<5% uniform elongation) were observed at test temperatures above 200-250 °C, due to flow localization near grain boundaries (exacerbated by having only 10-20 grains across the gage thickness of the miniaturized sheet tensile specimens). Scanning electron microscopy observation of the fracture surfaces found a transition from ductile transgranular to ductile intergranular fracture with increasing test temperature. Fission neutron irradiation to a dose of ∼0.7 displacements per atom (dpa) at temperatures between 100 and 240 °C produced a slight increase in strength and a significant decrease in ductility. The measured tensile elongation after irradiation increased with increasing irradiation temperature, with a uniform elongation of ∼3.3% observed at 240 °C. The electrical conductivity decreased slightly following irradiation, due to the presence of defect clusters and Ni, Zn, Co transmutation products. Considering also previously published fracture toughness data, this indicates that CuNiBe alloys have irradiated tensile and electrical properties comparable or superior to CuCrZr and oxide dispersion strengthened copper at temperatures

  2. Evaluation of high strength, high conductivity CuNiBe alloys for fusion energy applications

    SciTech Connect

    Zinkle, Steven J

    2014-06-01

    The unirradiated tensile properties for several different heats and thermomechanical treatment conditions of precipitation strengthened Hycon 3HPTM CuNiBe (Cu-2%Ni-0.35%Be in wt.%) have been measured over the temperature range of 20-500 C for longitudinal and long transverse orientations. The room temperature electrical conductivity has also been measured for several heats, and the precipitate microstructure was characterized using transmission electron microscopy. The CuNiBe alloys exhibit very good combination of strength and conductivity at room temperature, with yield strengths of 630-725 MPa and electrical conductivities of 65-72% International Annealed Copper Standard (IACS). The strength remained relatively high at all test temperatures, with yield strengths of 420-520 MPa at 500 C. However, low levels of ductility (<5% uniform elongation) were observed at test temperatures above 200-250 C, due to flow localization near grain boundaries (exacerbated by having only 10-20 grains across the gage thickness of the miniaturized sheet tensile specimens). Scanning electron microscopy observation of the fracture surfaces found a transition from ductile transgranular to ductile intergranular fracture with increasing test temperature. Fission neutron irradiation to a dose of ~0.7 displacements per atom (dpa) at temperatures between 100 and 240 C produced a slight increase in strength and a significant decrease in ductility. The measured tensile elongation increased with increasing irradiation temperature, with a uniform elongation of ~3.3% observed at 240 C. The electrical conductivity decreased slightly following irradiation, due to the presence of defect clusters and Ni, Zn, Co transmutation products. Considering also previously published fracture toughness data, this indicates that CuNiBe alloys have irradiated tensile and electrical properties comparable or superior to CuCrZr and oxide dispersion strengthened copper at temperatures <250 C, and may be an attractive

  3. High Strength Phosphogypsum and Its Use as a Building Material

    NASA Astrophysics Data System (ADS)

    Kanno, Wellington Massayuki; Rossetto, Hebert Luis; de Souza, Milton Ferreira; Máduar, Marcelo Francis; de Campos, Marcia Pires; Mazzilli, Barbara Paci

    2008-08-01

    A new process (patent applied) that works equally well with both plaster of mineral gypsum and phosphogypsum for the preparation of gypsum components, UCOS, has been developed. The process consists of the following steps: humidification of plaster by fine water droplets, uni-axial compression, hydration reaction and drying. Strong hydrogen bonds develop among the crystals together with adhesion provided by confined water that accounts for nearly 70% of the adhesion forces. By reducing the plaster to water ratio to close the minimum necessary, new features are generated. An experimental house has been constructed, in which walls and ceilings have been built of gypsum and phosphogypsum. Since phosphogypsum potentially contain radioactive elements, the application of an activity concentration index to the phosphogypsum employed in the building was carried out.

  4. High Output Piezo/Triboelectric Hybrid Generator

    PubMed Central

    Jung, Woo-Suk; Kang, Min-Gyu; Moon, Hi Gyu; Baek, Seung-Hyub; Yoon, Seok-Jin; Wang, Zhong-Lin; Kim, Sang-Woo; Kang, Chong-Yun

    2015-01-01

    Recently, piezoelectric and triboelectric energy harvesting devices have been developed to convert mechanical energy into electrical energy. Especially, it is well known that triboelectric nanogenerators have a simple structure and a high output voltage. However, whereas nanostructures improve the output of triboelectric generators, its fabrication process is still complicated and unfavorable in term of the large scale and long-time durability of the device. Here, we demonstrate a hybrid generator which does not use nanostructure but generates much higher output power by a small mechanical force and integrates piezoelectric generator into triboelectric generator, derived from the simultaneous use of piezoelectric and triboelectric mechanisms in one press-and-release cycle. This hybrid generator combines high piezoelectric output current and triboelectric output voltage, which produces peak output voltage of ~370 V, current density of ~12 μA·cm−2, and average power density of ~4.44 mW·cm−2. The output power successfully lit up 600 LED bulbs by the application of a 0.2 N mechanical force and it charged a 10 μF capacitor to 10 V in 25 s. Beyond energy harvesting, this work will provide new opportunities for developing a small, built-in power source in self-powered electronics such as mobile electronics. PMID:25791299

  5. High output piezo/triboelectric hybrid generator.

    PubMed

    Jung, Woo-Suk; Kang, Min-Gyu; Moon, Hi Gyu; Baek, Seung-Hyub; Yoon, Seok-Jin; Wang, Zhong-Lin; Kim, Sang-Woo; Kang, Chong-Yun

    2015-01-01

    Recently, piezoelectric and triboelectric energy harvesting devices have been developed to convert mechanical energy into electrical energy. Especially, it is well known that triboelectric nanogenerators have a simple structure and a high output voltage. However, whereas nanostructures improve the output of triboelectric generators, its fabrication process is still complicated and unfavorable in term of the large scale and long-time durability of the device. Here, we demonstrate a hybrid generator which does not use nanostructure but generates much higher output power by a small mechanical force and integrates piezoelectric generator into triboelectric generator, derived from the simultaneous use of piezoelectric and triboelectric mechanisms in one press-and-release cycle. This hybrid generator combines high piezoelectric output current and triboelectric output voltage, which produces peak output voltage of ~370 V, current density of ~12 μA · cm(-2), and average power density of ~4.44 mW · cm(-2). The output power successfully lit up 600 LED bulbs by the application of a 0.2 N mechanical force and it charged a 10 μF capacitor to 10 V in 25 s. Beyond energy harvesting, this work will provide new opportunities for developing a small, built-in power source in self-powered electronics such as mobile electronics. PMID:25791299

  6. High Output Piezo/Triboelectric Hybrid Generator

    NASA Astrophysics Data System (ADS)

    Jung, Woo-Suk; Kang, Min-Gyu; Moon, Hi Gyu; Baek, Seung-Hyub; Yoon, Seok-Jin; Wang, Zhong-Lin; Kim, Sang-Woo; Kang, Chong-Yun

    2015-03-01

    Recently, piezoelectric and triboelectric energy harvesting devices have been developed to convert mechanical energy into electrical energy. Especially, it is well known that triboelectric nanogenerators have a simple structure and a high output voltage. However, whereas nanostructures improve the output of triboelectric generators, its fabrication process is still complicated and unfavorable in term of the large scale and long-time durability of the device. Here, we demonstrate a hybrid generator which does not use nanostructure but generates much higher output power by a small mechanical force and integrates piezoelectric generator into triboelectric generator, derived from the simultaneous use of piezoelectric and triboelectric mechanisms in one press-and-release cycle. This hybrid generator combines high piezoelectric output current and triboelectric output voltage, which produces peak output voltage of ~370 V, current density of ~12 μA.cm-2, and average power density of ~4.44 mW.cm-2. The output power successfully lit up 600 LED bulbs by the application of a 0.2 N mechanical force and it charged a 10 μF capacitor to 10 V in 25 s. Beyond energy harvesting, this work will provide new opportunities for developing a small, built-in power source in self-powered electronics such as mobile electronics.

  7. Towards high strength nanocomposite magnets --- Approaches from the bottom

    NASA Astrophysics Data System (ADS)

    Liu, J. Ping

    2012-02-01

    Exchange-coupled nanocomposite magnets are regarded as the next generation of permanent magnetic materials, based on the theoretical predictions. However, many fundamental questions and technical challenges remain in understanding the inter-phase exchange interactions and in processing bulk nanocomposite magnets with enhanced energy products. We will review recent advancements in both the fundamental research and the materials processing technologies. New findings about the effects of soft-phase properties and interface conditions on the hard/soft phase exchange interactions will be presented. Particularly, the development of the bottom-up approaches in materials processing will be discussed. Novel methodology for nanoparticle synthesis including the salt-matrix annealing, surfactant-assisted ball milling and severe plastic deformation will be described. Unconventional compaction techniques including warm compaction and dynamic compaction are recommended because they can be used to retain desired nanoscale morphology for effective exchange coupling in bulk nanocomposite magnets. A perspective on fabrication of anisotropic nanocomposite magnets will be also given.

  8. Exceeding the limit of dynamics studies on biomolecules using high spin-lock field strengths with a cryogenically cooled probehead.

    PubMed

    Ban, David; Gossert, Alvar D; Giller, Karin; Becker, Stefan; Griesinger, Christian; Lee, Donghan

    2012-08-01

    Internal motions in the microsecond timescale have been proposed to play an active part in a protein's biological function. Nuclear magnetic resonance (NMR) relaxation dispersion is a robust method sensitive to this timescale with atomic resolution. However, due to technical limitations, the observation of motions faster than ∼40 μs for ¹⁵N nuclei was not possible. We show that with a cryogenically cooled NMR probehead, a high spin-lock field strength can be generated that is able to detect motions as fast as 25 μs. We apply this high spin-lock field strength in an NMR experiment used for characterizing dynamical processes. An on-resonance rotating-frame transverse relaxation experiment was implemented that allows for the detection of a 25 μs process from a dispersion curve, and transverse relaxation rates were compared at low and high spin-lock field strengths showing that at high field strengths contributions from chemical exchange with lifetimes up to 25 μs can be removed. Due to the increase in sensitivity towards fast motion, relaxation dispersion for a residue that undergoes smaller chemical shift variations due to dynamics was identified. This technique reduces the previously inaccessible window between the correlation time and the relaxation dispersion window that covers four orders of magnitude by a factor of 2. PMID:22743535

  9. Application technologies for effective utilization of advanced high strength steel sheets

    NASA Astrophysics Data System (ADS)

    Suehiro, Masayoshi

    2013-12-01

    Recently, application of high strength steel sheets for automobiles has increased in order to meet a demand of light weighting of automobiles to reduce a carbon footprint while satisfying collision safety. The formability of steel sheets generally decreases with the increase in strength. Fracture and wrinkles tend to occur easily during forming. The springback phenomenon is also one of the issues which we should cope with, because it makes it difficult to obtain the desired shape after forming. Advanced high strength steel sheets with high formability have been developed in order to overcome these issues, and at the same time application technologies have been developed for their effective utilization. These sheets are normally used for cold forming. As a different type of forming, hot forming technique has been developed in order to produce parts with ultra high strength. In this report, technologies developed at NSSMC in this field will be introduced.

  10. High strength nickel-base alloy with improved oxidation resistance up to 2200 degrees F

    NASA Technical Reports Server (NTRS)

    Freche, J. C.; Waters, W. J.

    1968-01-01

    Modifying the chemistry of the NASA TAZ-8 alloy and utilizing vacuum melting techniques provides a high strength, workable nickel base superalloy with improved oxidation resistance for use up to 2200 degrees F.