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Sample records for al-7 wt pct

  1. Numerical Simulation on the Die Filling Process of the Thixo-Forging of Al-7 wt pct Si/Al-22 wt pct Si Bimetal Composite

    NASA Astrophysics Data System (ADS)

    Wang, Guangxu; Huang, Honghua; Yang, Zhao; Shi, Xiaocheng; He, Xiaolong

    2015-10-01

    A bimetal semi-solid fluid has more complicated flow behaviors than a normal semi-solid fluid during thixo-forging. In order to clarify the detailed properties of the bimetal thixo-forging, the effects of billet temperatures and frictions on flow behaviors of the Al-7 wt pct Si/Al-22 wt pct Si bimetal thixo-forging were investigated by commercial software DEFORM-3D. The simulation results show that shear force was unable to be transferred from the upper billet on the drop die side to the bottom billet on the counter die side efficiently in the initial stage of die filling. Only when the upper billet severely deformed, did the shear force deform the bottom billet. A stiffer upper billet can enhance the efficiency of shear force transfer. The processing temperature, the relative stiffness between the upper billet and bottom billet, and frictions between dies and billets, as well as friction between billets, were important factors to control the interface outline of the bimetal parts. The experimental results are consistent with the simulation results.

  2. Porosity formation in AI-9 Wt Pct Si-3 Wt Pct Cu alloy systems: Metallographic observations

    NASA Astrophysics Data System (ADS)

    Roy, N.; Samuel, A. M.; Samuel, F. H.

    1996-02-01

    The formation of porosity in Al-9 wt Pct Si-3 wt Pct Cu-X alloys was studied as a function of (1) the hydrogen content of the melt; (2) the melt treatment additives, namely, modifier (Sr), grain refiner (TiB2), and primary silicon refiner (P); (3) alloying elements for precipitation hardening such as Mg and Zn; (4) intermetallics (α-iron, β-iron, sludge, and Al2Cu); and (5) solidification conditions (so-lidification time and solidus velocity). The results were statistically analyzed, based on the quanti-tative image analysis data of the porosity observed in samples obtained from a set of 72 solidification experiments. Metallographic aspects of pore size and pore morphology related to the preceding parameters and the possible mechanisms of porosity formation are highlighted in this article. The results show that a melt hydrogen content of 0.1 mL/100 g Al has the same effect on percentage porosity as that obtained with an addition of 185 ppm strontium to the melt. Grain refiner particles, phosphorus, and magnesium reduce percentage porosity, although in different magnitudes. A Mg-Sr or Mg-GR combination further reduces the percentage porosity observed in the casting. The β needles of the Al5FeSi intermetallic phase are very active as pore nucleation sites. All intermetallics, viz. β needles, α-Chinese script phase, Al2Cu phase, and sludge restrict pore growth and expansion. In-creasing the local solidification time or the solidus velocity increases the pore parameters. Pore growth in the two cases is attributed, respectively, to a diffusion-controlled growth process and to the formation of hot spots.

  3. Wear mechanisms in hybrid composites of graphite-20 pct SiC in A356 aluminum alloy (Al-7 pct Si-0. 3 pct Mg)

    SciTech Connect

    Ames, W.; Alpas, A.T. . Dept. of Mechanical Engineering)

    1995-01-01

    The wear behavior of A356 aluminum alloy (Al-7 pct Si-0.3 pct Mg) matrix composites reinforced with 20 vol pct SiC particles and 3 or 10 vol pct graphite was investigated. These hybrid composites represent the merging of two philosophies in tribological material design: soft-particle lubrication by graphite and hard-particle reinforcement by carbide particles. The wear tests were performed using a block-on-ring (SAE 52100 steel) wear machine under dry sliding conditions within a load range of 1 to 441 N. The microstructural and compositional changes that took place during wear were characterized using scanning electron microscopy (SEM), Auger electron spectroscopy (AES), energy-dispersive X-ray spectroscopy (EDXA), and X0ray diffractometry (XRD). The wear resistance of 3 pct graphite-20 pct SiC-A356 hybrid composite was comparable to 20 pct SiC-A356 without graphite at low and medium loads. At loads below 20 N, both hybrid and 20 pct SiC-A356 composites without graphite demonstrated wear rates up to 10 times lower than the unreinforced A356 alloy due to the load-carrying capacity of SiC particles. The wear resistance of 3 pct graphite 20 pct SiC-A356 was 1 to 2 times higher than 10 pct graphite-containing hybrid composites at high loads. However, graphite addition reduced the counterface wear. The unreinforced A356 and 20 pct SiC-A356 showed a transition from mild to severe wear at 95 N and 225 N, respectively. Hybrid composites with 3 pct and 10 pct graphite did not show such a transition over the entire load range, indicating that graphite improved the seizure resistance of the composites.

  4. Low gravity solidification structures in the tin-15 wt pct lead and tin-3 wt pct bismuth alloys

    NASA Technical Reports Server (NTRS)

    Johnston, M. H.; Parr, R. A.

    1982-01-01

    The tin-15 wt pct lead and tin-3 wt pct bismuth alloys have been solidified in the low-gravity environment provided by the Space Processing Applications Rocket (SPAR), on the KC-135 airplane, and at high 'g' levels in a centrifuge furnace. In each case the resultant cast structure was significantly different from that obtained in ground based experiments. Earlier low-gravity studies with the metal-model system NH4Cl-H2O presaged these results. This paper presents and discusses the influence of changes in the gravity force on the grain structure of these materials.

  5. Wear mechanisms in hybrid composites of Graphite-20 Pct SiC in A356 Aluminum Alloy (Al-7 Pct Si-0.3 Pct Mg)

    NASA Astrophysics Data System (ADS)

    Ames, W.; Alpas, A. T.

    1995-01-01

    The wear behavior of A356 aluminum alloy (Al-7 Pct Si-0.3 Pct Mg) matrix composites reinforced with 20 vol Pct SiC particles and 3 or 10 vol Pct graphite was investigated. These hybrid composites represent the merging of two philosophies in tribological material design: soft-particle lubrication by graphite and hard-particle reinforcement by carbide particles. The wear tests were performed using a block-on-ring (SAE 52100 steel) wear machine under dry sliding conditions within a load range of 1 to 441 N. The microstructural and compositional changes that took place during wear were characterized using scanning electron microscopy (SEM), Auger electron spectroscopy (AES), energy-dispersive X-ray spectroscopy (EDXA), and X-ray diffractometry (XRD). The wear resistance of 3 Pct graphite-20 Pct SiC-A356 hybrid composite was comparable to 20 Pct SiC-A356 without graphite at low and medium loads. At loads below 20 N, both hybrid and 20 Pct SiC-A356 composites without graphite demonstrated wear rates up to 10 times lower than the unreinforced A356 alloy due to the load-carrying capacity of SiC particles. The wear resistance of 3 Pct graphite 20 Pct SiC-A356 was 1 to 2 times higher than 10 Pct graphite-containing hybrid composites at high loads. However, graphite addition reduced the counterface wear. The unreinforced A356 and 20 Pct SiC-A356 showed a transition from mild to severe wear at 95 N and 225 N, respectively. Hybrid composites with 3 Pct and 10 Pct graphite did not show such a transition over the entire load range, indicating that graphite improved the seizure resistance of the composites. Tribolayers, mainly consisting of a compacted mixture of graphite, iron oxides, and aluminum, were generated on the surfaces of the hybrid composites. In the hybrid composites, the elimination of the severe wear (and hence the improvement in seizure resistance) was attributed to the reduction in friction-induced surface heating due to the presence of graphite- and iron

  6. Microstructure Evolution of Atomized Al-0.61 wt pct Fe and Al-1.90 wt pct Fe Alloys

    NASA Astrophysics Data System (ADS)

    Chen, Jian; Dahlborg, Ulf; Bao, Cui Min; Calvo-Dahlborg, Monique; Henein, Hani

    2011-06-01

    The microstructure evolution of impulse atomized powders of Al-0.61 wt pct and Al-1.90 wt pct Fe compositions have been investigated with a scanning electron microscope, transmission electron microscope, neutron diffraction, and backscattering electron diffraction (EBSD). Both hypoeutectic and hypereutectic compositions demonstrated similar macrostructure ( i.e., primary α-Al dendrites/cells with eutectic Al-Fe intermetallics decorated at the dendritic/cellular walls). Selected area electron diffraction (SAED) analysis and SAED pattern simulation identified the eutectic Al-Fe intermetallic as AlmFe ( m = 4.0-4.4). This is verified by neutron diffraction analysis. Cubic texture was observed by EBSD on the droplets with dendritic growth direction close to <111>. The possible reasons are discussed.

  7. Phase Development in a U-7 wt.% Mo vs. Al-7 wt.% Ge Diffusion Couple

    SciTech Connect

    E. Perez; D.D. Keiser, Jr.; Y.H. Sohn

    2013-10-01

    Fuel development for the Reduced Enrichment for Research and Test Reactors (RERTR) program has demonstrated that U-Mo alloys in contact with Al develop interaction regions with phases that have poor irradiation behavior. The addition of Si to the Al has been considered with positive results. Compositional modification to replace Si with Ge is now under evaluation to attempt to further improve irradiation behavior. In this study, the microstructural and phase development of a diffusion couple of U-7 wt.% Mo in contact with Al-7 wt.% Ge was examined by transmission electron microscopy, scanning electron microscopy and energy dispersive spectroscopy. The interdiffusion zone developed a microstructure that included the cubic-UGe3 phase and amorphous phases. The UGe3 phase was observed with and without Mo and Al solid solutioning developing a (U,Mo)(Al,Ge)3 phase.

  8. Phase development in a U-7 wt.% Mo vs. Al-7 wt.% Ge diffusion couple

    NASA Astrophysics Data System (ADS)

    Perez, E.; Keiser, D. D.; Sohn, Y. H.

    2013-10-01

    Fuel development for the Reduced Enrichment for Research and Test Reactors (RERTR) program has demonstrated that U-Mo alloys in contact with Al develop interaction regions with phases that have poor irradiation behavior. The addition of Si to the Al has been considered with positive results. In this study, compositional modification is considered by replacing Si with Ge to determine the effect on the phase development in the system. The microstructural and phase development of a diffusion couple of U-7 wt.% Mo in contact with Al-7 wt.% Ge was examined by transmission electron microscopy, scanning electron microscopy and energy dispersive spectroscopy. The interdiffusion zone developed a microstructure that included the cubic-UGe3 phase and amorphous phases. The UGe3 phase was observed with and without Mo and Al solid solution developing a (U,Mo)(Al,Ge)3 phase.

  9. SPALLATION STUDIES ON SHOCK LOADED U-6 WT PCT NB.

    SciTech Connect

    D. TONKS; ET AL

    2001-01-10

    Several spallation experiments have been performed on the 6 wt pct alloy of uranium using gas gun driven normal plate impacts with VISAR instrumentation and soft recovery. The nominal shock pressures achieved were 28, 34, 42, 50, 55, and 82 kbar. This paper will focus on spallation modeling, e.g. using the 1 D characteristics code CHARADE to simulate the free surface particle velocity. The spallation model involves the ductile growth and coalescence of voids. Metallographical examination of recovered samples and details of the experimental apparatus are discussed in a separate paper.

  10. Phase Transformation Behavior of Medium Manganese Steels with 3 Wt Pct Aluminum and 3 Wt Pct Silicon During Intercritical Annealing

    NASA Astrophysics Data System (ADS)

    Sun, Binhan; Fazeli, Fateh; Scott, Colin; Yue, Stephen

    2016-08-01

    Medium manganese steels alloyed with sufficient aluminum and silicon amounts contain high fractions of retained austenite adjustable to various transformation-induced plasticity/twinning-induced plasticity effects, in addition to a reduced density suitable for lightweight vehicle body-in-white assemblies. Two hot rolled medium manganese steels containing 3 wt pct aluminum and 3 wt pct silicon were subjected to different annealing treatments in the present study. The evolution of the microstructure in terms of austenite transformation upon reheating and the subsequent austenite decomposition during quenching was investigated. Manganese content of the steels prevailed the microstructural response. The microstructure of the leaner alloy with 7 wt pct Mn (7Mn) was substantially influenced by the annealing temperature, including the variation of phase constituents, the morphology and composition of intercritical austenite, the Ms temperature and the retained austenite fraction. In contrast, the richer variant 10 wt pct Mn steel (10Mn) exhibited a substantially stable ferrite-austenite duplex phase microstructure containing a fixed amount of retained austenite which was found to be independent of the variations of intercritical annealing temperature. Austenite formation from hot band ferrite-pearlite/bainite mixtures was very rapid during annealing at 1273 K (1000 °C), regardless of Mn contents. Austenite growth was believed to be controlled at early stages by carbon diffusion following pearlite/bainite dissolution. The redistribution of Mn in ferrite and particularly in austenite at later stages was too subtle to result in a measureable change in austenite fraction. Further, the hot band microstructure of both steels contained a large fraction of coarse-grained δ-ferrite, which remained almost unchanged during intercritical annealing. A recently developed thermodynamic database was evaluated using the experimental data. The new database achieved a better agreement

  11. Grain Size Effects on Primary, Secondary, and Tertiary Twin Development in Mg-4 wt pct Li (-1 wt pct Al) Alloys

    NASA Astrophysics Data System (ADS)

    Lentz, Martin; Behringer, Andreas; Fahrenson, Christoph; Beyerlein, Irene J.; Reimers, Walter

    2014-10-01

    Grain size effects on three generations of twins were investigated in extruded Mg-4 wt pct Li (-1 wt pct Al) alloys using electron-backscatter diffraction. Samples with three distinct grains sizes, yet the same texture and applied strain were analyzed. With these variables fixed, we show that compression and double twinning decrease substantially with decreasing grain size. We find that compression twinning exhibits a stronger grain size effect than tension twinning, whereas the compression twinning to double twinning transition is independent of grain size.

  12. Supercooling effects in Cu-10 wt pct Co alloys solidified at different cooling rates

    NASA Technical Reports Server (NTRS)

    Munitz, A.; Elder-Randall, S. P.; Abbaschian, R.

    1992-01-01

    Electromagnetic levitation and electron beam surface melting were employed to study the effects of supercooling and cooling rate on the solidification of Cu-10 wt pct Co alloys. Two major effects were observed in the supercooled alloys: the nucleation of a metastable copper-rich phase which contains 13 wt pct to 20 wt pct Co in samples supercooled between 105 and 150 K and liquid phase separation which occurs in samples supercooled 150 K or more. The microstructure of the electron beam melted surfaces consisted of very fine spheres which were similar to those of the sample supercooled more than 150 K but with a refined microstructure. The results indicate that a dynamic bulk supercooling of 150 K may exist in the molten pool during the solidification of electron beam melted surfaces.

  13. Relationship between Defect Size and Fatigue Life Distributions in Al-7 Pct Si-Mg Alloy Castings

    NASA Astrophysics Data System (ADS)

    Tiryakioğlu, Murat

    2009-07-01

    A new method for predicting the variability in fatigue life of castings was developed by combining the size distribution for the fatigue-initiating defects and a fatigue life model based on the Paris-Erdoğan law for crack propagation. Two datasets for the fatigue-initiating defects in Al-7 pct Si-Mg alloy castings, reported previously in the literature, were used to demonstrate that (1) the size of fatigue-initiating defects follow the Gumbel distribution; (2) the crack propagation model developed previously provides respectable fits to experimental data; and (3) the method developed in the present study expresses the variability in both datasets, almost as well as the lognormal distribution and better than the Weibull distribution.

  14. Microstructure, strength, and oxidation of a 10 wt pct zyttrite-Si3N4 ceramic

    NASA Technical Reports Server (NTRS)

    Dutta, S.; Buzek, B.

    1984-01-01

    Hot pressed Si3N4 doped with 10 wt pct zyttrite as a sintering aid was studied. An equiaxed, fine grained microstructure was predominant, with no apparent porosity. Bend strengths were determined at room temperature and high temperatures (up to 1370 C). Oxidation was measured by weight gain at 1370 C in air. The resulting material exhibited very good room temperature strength (755 MPa). The work showed that room temperature strength can be improved significantly by using controlled Si3N4 powder with 10 wt pct zyttrite. High temperature strength (514 MPa) at 1370 C was nearly double that of hot-pressed Si3N4 (NC-132). The oxidation resistance at 1370 C was also higher than that of NC-132.

  15. Growth-speed dependence of primary arm spacings in directionally solidified Pb-10 wt pct Sn

    NASA Technical Reports Server (NTRS)

    Chopra, M. A.; Tewari, S. N.

    1991-01-01

    The dependence of primary arm spacings on growth speed has been investigated for cellular and dendritic arrays in directionally solidified Pb-10 wt pct Sn. The spatial arrangements of cells and dendrites, as given by their coordination number, are not very different from each other. The primary arm spacing maxima and the cell-to-dendrite transition appear to be strongly influenced by the magnitude of the solute partition coefficient (k). The planar-to-cellular transition in Pb-Sn (k = 0.50) is supercritical as compared to the subcritical behavior reported in Al-Cu (k = 0.14) and succinonitrile-acetone (k = 0.1).

  16. Estimation of crack closure stresses for in situ toughened silicon nitride with 8 wt pct scandia

    NASA Technical Reports Server (NTRS)

    Choi, Sung R.; Salem, Jonathan A.; Sanders, William A.

    1992-01-01

    An 8-wt pct-scandia silicon nitride with an elongated grain structure was fabricated. The material exhibited high fracture toughness and a rising R-curve as measured by the indentation strength technique. The 'toughening' exponent m was found to be m about 0.1. The high fracture toughness and R-curve behavior was attributed mainly to bridging of the crack faces by the elongated grains. The crack closure (bridging) stress distribution in the wake region of the crack tip was estimated as a function of crack size from the R-curve data, with an arbitrarily assumed distribution function.

  17. The unidirectional solidification of Al-4 wt pct Cu ingots in microgravity

    NASA Astrophysics Data System (ADS)

    Cahoon, J. R.; Chaturvedi, M. C.; Tandon, K. N.

    1998-03-01

    Three Al-4 wt pct Cu alloy ingots, 10 mm in diameter and 25-mm long, were unidirectionally solidified in microgravity during the flight of a sounding rocket, with solidification rates of about 1.6×10-4 m/s and temperature gradients of about 2600 K/m. The apparatus was comprised of three muffle furnaces, which melted the ingots prior to the launch of the rocket. Unidirectional solidification of the ingots was accomplished by chill plates attached to the furnaces, which were withdrawn from the ingots during the microgravity portion of the flight, bringing the chill plates into contact with the bases of the capsules containing the ingots. Solidification was complete in less than 4 minutes. For comparison, several ground-based ingots were solidified in unit gravity under similar conditions. Metallographic analysis of the solidified ingots showed that the macrostructures of the unit-gravity and microgravity ingots were similar, all exhibiting columnar grains. However, the microstructures were significantly different, with the microgravity ingots exhibiting primary dendrite spacings about 40 pct larger than the unit-gravity ingots and secondary dendrite arm spacings about 85 pct larger. The larger dendrite spacings for the ingots solidified in microgravity are explained by lower dendrite growth velocities. The absence of convective mixing in the microgravity ingots slightly increased temperature gradients in the liquid portion of the alloy during solidification, which resulted in decreased growth velocities.

  18. Microstructural Evolution of the 55 Wt Pct Al-Zn Coating During Press Hardening

    NASA Astrophysics Data System (ADS)

    Lee, Chang Wook; De Cooman, Bruno Charles

    2014-09-01

    Press hardening is increasingly being used to produce ultra-high strength steel parts for passenger cars. Al-Si, Zn, and Zn-alloy coatings have been used to provide corrosion protection to press hardening steel grades. The use of coatings has drawbacks such as coating delamination or liquid metal-induced embrittlement. In the present work, the microstructural evolution of Al-Zn coating during press hardening was studied. The 55 wt pct Al-Zn coating can in principle provide both Al barrier protection and Zn cathodic protection to press hardened steel. During the heat treatment associated with the press hardening, the 55 wt pct Al-Zn alloy coating is converted to an intermetallic surface layer of Fe2Al5 and a FeAl intermetallic diffusion layer. The Zn is separated from both intermetallic compounds and accumulates at grain boundaries and at the surface. This Zn separation process is beneficial in terms of providing cathodic protection to Al-Zn coated press hardening steel.

  19. Electrical conductivity in directionally solidified lead-9 and -20 wt pct copper alloys

    NASA Technical Reports Server (NTRS)

    Kim, Shinwoo; Flanagan, W. F.; Lichter, B. D.; Grugel, R. N.

    1993-01-01

    Composites consisting of aligned copper dendrites in a lead matrix have been produced by directional solidification processing for potential application as grids in lead-acid batteries. To promote a uniform composite of aligned copper dendrites in a protective lead matrix, two alloy compositions, Pb-9 and -20 wt pct Cu, have been directionally solidified through a temperature gradient of 4.5 K/mm at constant growth velocities which ranged from 1 to 100 micron/s. With slow growth rates (below about 10 microns/s), the copper dendrites were generally columnar and continuous along the sample length; at higher velocities (above 60 microns/s), they assumed an intricate and equiaxed morphology. In accordance with copper content and growth rate, the electrical conductivity of the directionally solidified composites was found to be as much as a 2.5 times that of pure lead. The results are compared with that predicted by a model based on a geometrical dendrite.

  20. CAFE simulation of columnar-to-equiaxed transition in Al-7wt%Si alloys directionally solidified under microgravity

    NASA Astrophysics Data System (ADS)

    Liu, D. R.; Mangelinck-Noël, N.; Gandin, Ch-A.; Zimmermann, G.; Sturz, L.; Nguyen Thi, H.; Billia, B.

    2016-03-01

    A two-dimensional multi-scale cellular automaton - finite element (CAFE) model is used to simulate grain structure evolution and microsegregation formation during solidification of refined Al-7wt%Si alloys under microgravity. The CAFE simulations are first qualitatively compared with the benchmark experimental data under microgravity. Qualitative agreement is obtained for the position of columnar to equiaxed transition (CET) and the CET transition mode (sharp or progressive). Further comparisons of the distributions of grain elongation factor and equivalent diameter are conducted and reveal a fair quantitative agreement.

  1. Effect of Nickel Precoating on Wettability of Twinning-Induced Plasticity Steels by Liquid Zn-0.23 Wt Pct Al

    NASA Astrophysics Data System (ADS)

    Kim, Yunkyum; Lee, Joonho; Shin, Kwang-Soo; Jeon, Sun-Ho; Chin, Kwang-Geun

    2016-07-01

    The effect of the nickel precoating on the wettability and the corresponding coating property of twinning-induced plasticity steel (17 wt pct Mn-1.2 wt pct Al-0.1 wt pct Si-0.5 wt pct C) by liquid Zn-0.23 wt pct Al were investigated. Annealing and Zn coating experiments were carried out in a galvanization simulator, and Zn wetting experiments were performed with a dispensed drop test machine. The experimental results showed that nickel precoating improved the Zn wetting property. SEM, XPS, and TEM analyses showed that nickel precoating decreased the thickness of surface oxides and thus improved the Zn coating property. It was speculated that oxygen adsorption on the nickel surface might be suppressed. In addition, Al2O3 was found just below the nickel precoating layer, and this indicated that the oxygen potential in the subsurface region was considerably decreased.

  2. Influence of the Thermomechanical Treatment on the Intergranular Corrosion Susceptibility of Zn-Modified Al-5.1 Wt Pct Mg-0.7 Wt Pct Mn Alloy Sheet

    NASA Astrophysics Data System (ADS)

    Halap, Akram; Radetić, Tamara; Popović, Miljana; Romhanji, Endre

    2014-09-01

    In this study, the effect of thermomechanical treatment on intergranular corrosion (IGC) susceptibility of the Zn-modified Al-5.1 wt pct Mg-0.7 wt pct Mn alloy plates was investigated. The specimens underwent varied amounts of cold work, while final annealing was conducted in the 493 K to 533 K (220 °C to 260 °C) temperature range. It was shown that the extent of cold work, especially at lower temperatures of treatment, had a profound effect on the corrosion resistance of the alloy. Such observation was in direct correlation with the morphology of precipitated ternary grain boundary phase (Al-Mg-Zn). Microstructural characterization showed that, depending on the amount of cold work, different deformation substructures were created, which, in turn, influenced kinetics and the mechanism of precipitation. Wetting of the grain boundaries by the ternary grain boundary phase (Al-Mg-Zn) was a signature of the IGC susceptible state and occurred in the specimens that were subjected to a lower degree of cold work. The specimens that underwent a higher degree of cold work (over 30 pct) showed superior corrosion resistance as a result of ternary grain boundary phase (Al-Mg-Zn) precipitation in the form of discrete particles at the grain boundaries as well as in grain interiors.

  3. Recrystallization Texture Transition in Fe-2.1 Wt Pct Si Steel by Different Cold Rolling Reduction

    NASA Astrophysics Data System (ADS)

    Shan, Ning; Sha, Yuhui; Zhang, Fang; Liu, Jinlong; Zuo, Liang

    2015-05-01

    The competition dependent on cold rolling reduction among main recrystallization texture components in Fe-2.1 wt pct Si sheets was investigated from the hot band characterized by strong Cube ({001}<100>) at center layer and weak Goss ({110}<001>) at quarter layer. The deformation and recrystallization textures through thickness were both analyzed by X-ray diffraction technique. Goss, Cube, and {111}<112> components dominate the recrystallization texture in sequence with the cold rolling reduction increasing from 60 to 90 pct. This recrystallization texture transition with cold rolling reduction can be explained in terms of the number and nature of nucleation sites for various texture components. A variety of final recrystallization textures are proposed for non-oriented silicon steel by designing texture and microstructure of hot band and cold rolling reduction.

  4. Electrolytic Deposition and Diffusion of Lithium onto Magnesium-9 Wt Pct Yttrium Bulk Alloy in Low-Temperature Molten Salt of Lithium Chloride and Potassium Chloride

    NASA Astrophysics Data System (ADS)

    Dong, Hanwu; Wu, Yaoming; Wang, Lidong; Wang, Limin

    2009-10-01

    The electrolytic deposition and diffusion of lithium onto bulk magnesium-9 wt pct yttrium alloy cathode in molten salt of 47 wt pct lithium chloride and 53 wt pct potassium chloride at 693 K were investigated. Results show that magnesium-yttrium-lithium ternary alloys are formed on the surface of the cathodes, and a penetration depth of 642 μm is acquired after 2 hours of electrolysis at the cathodic current density of 0.06 A·cm-2. The diffusion of lithium results in a great amount of precipitates in the lithium containing layer. These precipitates are the compound of Mg41Y5, which arrange along the grain boundaries and hinder the diffusion of lithium, and solid solution of yttrium in magnesium. The grain boundaries and the twins of the magnesium-9 wt pct yttrium substrate also have negative effects on the diffusion of lithium.

  5. Calorimetric Study of Phase Stability and Phase Transformation in U- xZr ( x = 2, 5, 10 wt pct) Alloys

    NASA Astrophysics Data System (ADS)

    Rai, Arun Kumar; Subramanian, Raju; Hajra, Raj Narayan; Tripathy, Haraprasanna; Rengachari, Mythili; Saibaba, Saroja

    2015-11-01

    A comprehensive calorimetric study of high-temperature phase equilibria and phase transformation characteristics in U- xZr ( x = 2, 5, 10 wt pct) alloys has been undertaken, as a function of heating and cooling rates. It is found that the following sequence of phase transformation takes place upon slow heating in annealed U-2 wt pct Zr alloy: α + α' + δ-UZr2 → α + γ 2 → β + γ 2 → β + γ 1 → γ. For alloys of 5 and 10 wt pct Zr, the additional presence of a miscibility gap ( γ 1 U-rich bcc + γ 2 Zr-rich bcc) in the high-temperature γ(bcc) phase region resulted in the following transformation sequence: α + α' + δ-UZr2 → α + γ 2 → β + γ 2 → γ 1 + γ 2 → γ. Further, it has been demonstrated that depending on the nature of starting microstructure, namely whether it is α eq + δ-UZr2, or a mix of α' + α eq + δ-UZr2 phases, the relative extents of two possible co-occurring modes of the first on-heating phase transformation step differ. In case of starting microstructure having mixture of three phases α' + α eq + δ-UZr2, it is found that α'-martensite relaxation via α' + α eq + δ-UZr2 → α eq + δ-UZr2 constitutes the first on-heating thermal response. The α'-martensitic relaxation is very closely followed by the dissolution of δ-UZr2. The co-occurrence of these two events gives rise to a composite thermal arrest in a normal dynamic calorimetry profile. However, if the starting microstructure is the one having the equilibrium mix of α eq and δ-UZr2, then only the peritectoidal dissolution of δ-UZr2 is found in the calorimetry profile. Unless, a very slow cooling rate of the order of 0.1 K min-1 is adopted from high-temperature γ(bcc) phase, it is not possible to obtain 100 pct of α eq phase along with equilibrium amount of δ-UZr2. At normal and high cooling rates, it is possible to suppress the diffusional decomposition of γ to varying extents. The direct γ → α'-martensite transformation has been observed at

  6. Evolution of microstructure during fabrication of Zr-2.5 wt pct Nb ally pressure tubes

    SciTech Connect

    Srivastava, D.; Dey, G.K.; Banerjee, S.

    1995-10-01

    Microstructural changes occurring during the fabrication of Zr-2.5 pct Nb alloy pressure tubes by a modified route, involving hot extrusion followed by two pilgering operations with an intermediate annealing step, have been examined in detail. In the conventional fabrication route, the hot extrusion step is followed by a single cold drawing operation in which the cold work to the extent of 25 pct is imparted to the material for achieving the required mechanical properties. Tensile properties obtained at each stage of fabrication have been evaluated and compared between the two processes. The main aim of this work has been to produce a microstructure and texture which are know n to yield a lower irradiation growth. Additionally, suitable annealing conditions have been optimized for the intermediate annealing which annihilates the cold work introduced by the first cold pilgering operation without disturbing the two-phase elongated microstructure. This elongated {alpha} + {beta}{sub I} microstructure is required for obtaining the desired level of strength at 310 C. The final microstructure and the crystallographic texture of the finished pressure tube have been compared with those reported for the conventionally processed material.

  7. Observation of the TWIP + TRIP Plasticity-Enhancement Mechanism in Al-Added 6 Wt Pct Medium Mn Steel

    NASA Astrophysics Data System (ADS)

    Lee, Seawoong; Lee, Kyooyoung; De Cooman, Bruno C.

    2015-06-01

    The intercritically annealed Fe-0.15 pctC-6.0 pctMn-1.5 pctSi-3.0 pctAl and Fe-0.30 pctC-6.0 pctMn-1.5 pctSi-3.0 pctAl medium Mn steels were found to have improved mechanical properties due to the TWIP and TRIP plasticity-enhancing mechanisms being activated in succession during tensile deformation. The increase of the C content from 0.15 to 0.30 pct resulted in ultra-high strength properties and a strength-ductility balance of approximately 65,000 MPa-pct, i.e., equivalent to the strength-ductility balance of high Mn TWIP steel with a fully austenitic microstructure.

  8. An examination of the interparticle contact area during sintering of W-0.3 wt pct Co

    SciTech Connect

    Mitlin, D.; German, R.M.

    1998-04-01

    As a powder compact sinters, its microstructure evolves. One way to quantify the scale of the microstructure is to consider the interparticle contact area. This study examines two known models for calculating the interparticle contact area: the classic two-sphere model and the Voronoi cell model. Both models have particular assumptions about the microstructure that make them not applicable for treating densification to near full density with concurrent grain growth. The classic two-sphere model assumes a regular packing of particles and a perfectly spherical particle geometry and neglects an increasing particle coordination number with sintering. The Voronoi cell model assumes that the scale of the microstructure remains constant; i.e., as long as the compact is densifying, grain growth does not occur. The authors propose a modified Voronoi cell that accounts for an increasing grain size, making it applicable to a general case where grain growth occurs during sintering. The three models are compared to the interparticle contact area data, obtained by stereology techniques, for W-0.3 wt pct Co sintered from green state to near full density. The original Voronoi cell model fits the data only at low temperatures, before the onset of grain growth. Below approximately 90 pct relative density, the two-sphere model with an assumed coordination number of six (coordination number in a green compact) and the modified Voronoi cell model provide a good fit to the data. At higher densities, both models overestimate the interparticle contact area.

  9. Formation of Delta Ferrite in 9 Wt Pct Cr Steel Investigated by In-Situ X-Ray Diffraction Using Synchrotron Radiation

    NASA Astrophysics Data System (ADS)

    Mayr, P.; Palmer, T. A.; Elmer, J. W.; Specht, E. D.; Allen, S. M.

    2010-10-01

    In-situ X-ray diffraction (XRD) measurements using high energy synchrotron radiation were performed to monitor in real time the formation of delta ferrite in a martensitic 9 wt pct chromium steel under simulated weld thermal cycles. Volume fractions of martensite, austenite, and delta ferrite were measured as a function of temperature at a 10 K/s heating rate to 1573 K (1300 °C) and subsequent cooling. At the peak temperature, the delta ferrite concentration rose to 19 pct, of which 17 pct transformed back to austenite on subsequent cooling.

  10. Microstructure and Corrosion Behavior of Hf-40 Wt Pct Ti Alloy in Nitric Acid Medium for Reprocessing Applications

    NASA Astrophysics Data System (ADS)

    Jayaraj, J.; Ravi, K. R.; Mallika, C.; Kamachi Mudali, U.

    2016-09-01

    The Hf-40 wt pct Ti (Hf-Ti) alloy was developed for neutron poison application in the spent nuclear fuel reprocessing plant. The furnace-cooled Hf-Ti sample exhibited the microstructure comprising equiaxed-α, lamellar-α, and feathery-α. The water-quenched Hf-Ti sample confirmed the presence of lath and internally twinned martensite. In comparison to the furnace-cooled sample, low corrosion current density and passivation current density values obtained for the water-quenched Hf-Ti in 6 M HNO3 at 298 K (25 °C) indicated better passivation ability. The martensitic structure exhibited high hardness (660 HV) and negligible corrosion rate in 6 M nitric acid at 298 K (25 °C). X-ray photoelectron spectroscopic (XPS) analysis confirmed that passivation behavior of this alloy was due to the protective passive film composed of TiO2 and HfO2.

  11. Microstructure and Corrosion Behavior of Hf-40 Wt Pct Ti Alloy in Nitric Acid Medium for Reprocessing Applications

    NASA Astrophysics Data System (ADS)

    Jayaraj, J.; Ravi, K. R.; Mallika, C.; Kamachi Mudali, U.

    2016-06-01

    The Hf-40 wt pct Ti (Hf-Ti) alloy was developed for neutron poison application in the spent nuclear fuel reprocessing plant. The furnace-cooled Hf-Ti sample exhibited the microstructure comprising equiaxed-α, lamellar-α, and feathery-α. The water-quenched Hf-Ti sample confirmed the presence of lath and internally twinned martensite. In comparison to the furnace-cooled sample, low corrosion current density and passivation current density values obtained for the water-quenched Hf-Ti in 6 M HNO3 at 298 K (25 °C) indicated better passivation ability. The martensitic structure exhibited high hardness (660 HV) and negligible corrosion rate in 6 M nitric acid at 298 K (25 °C). X-ray photoelectron spectroscopic (XPS) analysis confirmed that passivation behavior of this alloy was due to the protective passive film composed of TiO2 and HfO2.

  12. Verification of the Mechanism of Grain Refinement by Ultrasonic Treatment of Aluminum-4 Wt Pct Silicon Molten Alloy

    NASA Astrophysics Data System (ADS)

    Matsuda, Kazuki; Takehara, Tsuyoshi; Yang, Minghan; Uno, Hikaru; Kubo, Takashi; Miyano, Gaku; Yoshida, Makoto

    2016-05-01

    Ultrasonic treatment (UST) of molten metals produces a fine grain microstructure. Several mechanisms of grain refining by UST have been suggested; however, experimental verification has not yet established the actual mechanism. In this study, UST was applied to Al-4 wt pct Si molten alloy (1) above the liquidus temperature, (2) during undercooling before recalescence, (3) during recalescence, and (4) after recalescence. After UST treatment, the average grain sizes of the solidified samples were measured, and the effects of UST were evaluated. In the case of (1), the temperatures of the crucible, ultrasonic horn, and the atmosphere of the molten alloy were also confirmed above the liquidus temperature, and a finer grain structure was obtained. This result reveals that UST promotes the nonequilibrium nucleation mechanism. UST during (2) and (3) also caused finer grain microstructures, whereas (4) did not. UST during undercooling hastened nucleation. However, the previously reported mechanism of the breaking dendrite was not activated by UST after recalescence.

  13. Anelastic relaxation in Al-4 wt pct Cu-Al{sub 2}O{sub 3} fiber-reinforced composites

    SciTech Connect

    Sgobba, S.; Parrini, L.; Kuenzi, H.U.; Ilschner, B.

    1995-10-01

    In many industrial applications, like high precision weighing and positioning, the elastic and dimensional stability of materials is required at a nanometric scale. High-resolution laser interferometry and mechanical spectroscopy have been employed to measure low-temperature anelastic creep of the short-fiber-reinforced composite Al-4 wt pct Cu-Al{sub 2}O{sub 3}. The typical strain resolution of the laser interferometer is 10{sup {minus}10}. Fiber reinforcement has been found to increase the dislocation density n the metal matrix; in parallel, damping and anelastic creep are enhanced. This behavior has been explained on the basis of the structure of interparticle dislocations and {theta}{prime} relaxation.

  14. Primary arm spacing in directionally solidified Pb-10 wt pct Sn alloys

    NASA Technical Reports Server (NTRS)

    Chopra, M. A.; Tewari, S. N.

    1990-01-01

    The dependence of primary arm spacings on growth speed was investigated for cellular and dendritic arrays in Pb-10 wt percent Sn samples directionally solidified under a constant positive thermal gradient in the melt. The gradient of constitutional supercooling was varied from almost zero (near the break-down of the planar liquid-solid interface at small growth speeds, cellular morphology) to near unity (large growth speeds, dendritic morphology). The spatial arrangements of cells and dendrites, as given by their coordination number, are not very different from each other. It appears that primary arm spacing maxima and the cell to dendrite transition are strongly influenced by the magnitude of the solute partition coefficient. The planar to cellular bifurction is supercritical in Pb-Sn which has a high partition coefficient, as compared to the subcritical behavior reported in Al-Cu and succinonitrile-acetone, both of which have low partition coefficients. The primary arm spacing model due to Hunt agrees with the experimentally observed trend for the whole growth regime. There is a good quantitative agreement at higher grdients of supercooling. However, the model overpredicts the primary arm spacings at low gradients of constitutional supercooling.

  15. On the Densification Behavior of (0.2, 0.5, and 1 Wt Pct) CNT-YSZ Ceramic Composites Processed via Spark Plasma Sintering

    NASA Astrophysics Data System (ADS)

    Karanam, Abhinav; Bichler, Lukas; Fong, Randy

    2015-08-01

    Yttria-Stabilized Zirconia (YSZ) is a promising thermal insulating ceramic for high temperature applications due to its stability and chemical inertness. As was demonstrated with other technical ceramics ( e.g., Alumina), addition of Single-Wall Carbon Nanotubes (CNTs) to a ceramic matrix may significantly enhance its mechanical properties. In this work, 8 mol pct YSZ with 0.2, 0.5, and 1 wt pct CNT composites were fabricated via the spark plasma sintering process. The densification, Vicker's microhardness, specific gravity, and microstructure evolution of the composites were investigated. The results suggest that the addition of CNTs to YSZ hindered densification and grain growth during SPS processing leading to inhomogeneous grain size distribution. However, the CNTs had a profound impact on the hardness of the composite ceramics, with an increase from 697 HV (YSZ) to 1195 HV (1 wt pctCNT-YSZ).

  16. High-Temperature Oxidation and Decarburization of 14.55 wt pct Cr-Cast Iron in Dry Air Atmosphere

    NASA Astrophysics Data System (ADS)

    Efremenko, V. G.; Chabak, Yu. G.; Lekatou, A.; Karantzalis, A. E.; Efremenko, A. V.

    2016-04-01

    The oxidation and decarburization behavior of 14.55 wt pct Cr-cast iron at 1273 K to 1423 K (1000 °C to 1150 °C) in a dry air atmosphere was studied. A gravimetric investigation showed that intensive oxidation of cast iron takes place at temperatures above 1273 K (1000 °C). It is found that oxidizing heating is accompanied by decarburization, which manifests itself in secondary and eutectic carbide dissolution. The volume fraction of carbides decreases with temperature and holding duration increasing. Decarburization results in the formation of a decarburized layer up to 4 mm in depth. A carbide-free layer in depth up to 100 μm appears in the free surface after 6 to 8 hours holding at 1373 K to 1423 K (1100 °C to 1150 °C). Preliminary activation energy calculations suggested that the eutectic carbide dissolution at the depths of 50 to 400 μm is controlled by carbon diffusion in austenite. The dissolution of eutectic carbides involves a capillarity-induced mechanism, which consists of formation and growth of capillary cavities inside carbides.

  17. Response of Mg Addition on the Dendritic Structures and Mechanical Properties of Hypoeutectic Al-10Si (Wt Pct) Alloys

    NASA Astrophysics Data System (ADS)

    Karaköse, Ercan; Yildiz, Mehmet; Keskin, Mustafa

    2016-08-01

    Rapidly solidified hypoeutectic Al-10Si- xMg ( x = 0, 5, 10 wt pct) alloys were produced by the melt-spinning method. The phase composition was identified by X-ray diffractometry, and the microstructures of the alloys were characterized by scanning electron microscopy. The melting characteristics were studied by differential scanning calorimetry and differential thermal analysis under an Ar atmosphere. The mechanical properties of the melt-spun and conventionally solidified alloys were tested by tensile-strength and Vickers microhardness tests. The results illustrate that the cooling rate and solidification time of 89 μm thick melt-spun ribbon were estimated to be 2.97 × 107 K s-1 and 9.31 × 10-6 s, respectively. Nanoscale Si spot particles were observed growing on the surface of the dendritic α-Al matrix and the average sizes of these spots ranged from 10 to 50 nm. The improvement in the tensile properties and microhardness was related to structural refinement and the supersaturated α-Al solid solution; the nanoscale-dispersed Si spot particles made a significant improvement to the mechanical properties of the melt-spun ribbon. Detailed electrical resistivity tests of the ribbons were carried out at temperatures of 300 K to 800 K (27 °C to 527 °C).

  18. Response of Mg Addition on the Dendritic Structures and Mechanical Properties of Hypoeutectic Al-10Si (Wt Pct) Alloys

    NASA Astrophysics Data System (ADS)

    Karaköse, Ercan; Yildiz, Mehmet; Keskin, Mustafa

    2016-05-01

    Rapidly solidified hypoeutectic Al-10Si-xMg (x = 0, 5, 10 wt pct) alloys were produced by the melt-spinning method. The phase composition was identified by X-ray diffractometry, and the microstructures of the alloys were characterized by scanning electron microscopy. The melting characteristics were studied by differential scanning calorimetry and differential thermal analysis under an Ar atmosphere. The mechanical properties of the melt-spun and conventionally solidified alloys were tested by tensile-strength and Vickers microhardness tests. The results illustrate that the cooling rate and solidification time of 89 μm thick melt-spun ribbon were estimated to be 2.97 × 107 K s-1 and 9.31 × 10-6 s, respectively. Nanoscale Si spot particles were observed growing on the surface of the dendritic α-Al matrix and the average sizes of these spots ranged from 10 to 50 nm. The improvement in the tensile properties and microhardness was related to structural refinement and the supersaturated α-Al solid solution; the nanoscale-dispersed Si spot particles made a significant improvement to the mechanical properties of the melt-spun ribbon. Detailed electrical resistivity tests of the ribbons were carried out at temperatures of 300 K to 800 K (27 °C to 527 °C).

  19. Modification of the Cast Structure in a Cu-12.6 Wt Pct Sn Alloy by Heat Treatment in the Semisolid State

    NASA Astrophysics Data System (ADS)

    Bandyopadhyay, Biswarup; Mishra, Dewika; Bhattacharyya, Ashish; Mallik, Manab

    2015-10-01

    The dendritic structure in a cast Cu-12.6 wt pct Sn alloy can be transformed to a globular structure if the alloy is heat treated in the semisolid range. A Cu-12.6 wt pct Sn alloy has a wide solidification range which encourages the development of a cored dendritic structure during solidification. In order to transform it into a globular structure, heat treatment was carried out separately at three temperatures in the semisolid range, namely 1183 K, 1153 K, and 1123 K (910 °C, 880 °C, and 850 °C) with corresponding liquid volume fractions of 50, 40, and 20 pct, respectively. An attempt was made to optimize the temperature and vol pct of liquid combination. It was observed that microstructural modification proceeded mainly through coarsening, fragmentation, and spheroidization of the dendrite arms. Semisolid heat treatment at 1123 K (850 °C) for 2 hours with 20 vol pct liquid yielded the best result. This microstructure was compared with the microstructure developed by solid-state heat treatment at 1023 K (750 °C) for 2 hours. Assessment of the structure-property co-relation demonstrated that hardness, yield stress, ultimate tensile stress, and toughness of the semisolid heat-treated samples were superior to those of subcritically annealed samples.

  20. The Work Softening by Deformation-Induced Disordering and Cold Rolling of 6.5 wt pct Si Steel Thin Sheets

    NASA Astrophysics Data System (ADS)

    Wang, Xianglong; Li, Haoze; Zhang, Weina; Liu, Zhenyu; Wang, Guodong; Luo, Zhonghan; Zhang, Fengquan

    2016-06-01

    As-cast strip of 6.5 wt pct Si steel was fabricated by twin-roll strip casting. After hot rolling at 1323 K (1050 °C), thin sheets with the thickness of 0.35 mm were produced by warm rolling at 373 K (100 °C) with rolling reductions of 15, 25, 35, 45, 55, and 65 pct. Influence of warm rolling reduction on ductility was investigated by room temperature bending test. The measurement of macro-hardness showed that "work softening" could begin when the warm rolling reduction exceeded 35 pct. The room temperature ductility of the thin sheets gradually increased with the increase of warm rolling reductions, and the plastic deformation during bending began to form when the warm rolling reduction was greater than 45 pct, the 65 pct rolled thin sheet exhibited the maximum plastic deformation of about 0.6 pct during bending at room temperature, with a few small dimples having been observed on the fracture surfaces. B2-ordered domains were formed in the 15, 25, 35, 45, and 55 pct rolled specimens, and their average size decreased with the increase of warm rolling reductions. By contrast, no B2-ordered domain could be found in the 65 pct rolled specimen. It had been observed that large-ordered domains could be split into several small parts by the slip of partial super-dislocations during warm rolling, which led to significant decrease of the order degree to cause the phenomenon of deformation-induced disordering. On the basis of these results, cold rolling schedule was developed to successfully fabricate 0.25-mm-thick sheets with good surface qualities and magnetic properties from warm rolled sheets.

  1. The Work Softening by Deformation-Induced Disordering and Cold Rolling of 6.5 wt pct Si Steel Thin Sheets

    NASA Astrophysics Data System (ADS)

    Wang, Xianglong; Li, Haoze; Zhang, Weina; Liu, Zhenyu; Wang, Guodong; Luo, Zhonghan; Zhang, Fengquan

    2016-09-01

    As-cast strip of 6.5 wt pct Si steel was fabricated by twin-roll strip casting. After hot rolling at 1323 K (1050 °C), thin sheets with the thickness of 0.35 mm were produced by warm rolling at 373 K (100 °C) with rolling reductions of 15, 25, 35, 45, 55, and 65 pct. Influence of warm rolling reduction on ductility was investigated by room temperature bending test. The measurement of macro-hardness showed that "work softening" could begin when the warm rolling reduction exceeded 35 pct. The room temperature ductility of the thin sheets gradually increased with the increase of warm rolling reductions, and the plastic deformation during bending began to form when the warm rolling reduction was greater than 45 pct, the 65 pct rolled thin sheet exhibited the maximum plastic deformation of about 0.6 pct during bending at room temperature, with a few small dimples having been observed on the fracture surfaces. B2-ordered domains were formed in the 15, 25, 35, 45, and 55 pct rolled specimens, and their average size decreased with the increase of warm rolling reductions. By contrast, no B2-ordered domain could be found in the 65 pct rolled specimen. It had been observed that large-ordered domains could be split into several small parts by the slip of partial super-dislocations during warm rolling, which led to significant decrease of the order degree to cause the phenomenon of deformation-induced disordering. On the basis of these results, cold rolling schedule was developed to successfully fabricate 0.25-mm-thick sheets with good surface qualities and magnetic properties from warm rolled sheets.

  2. Modeling and Experimental Validation of Rapid Cooling and Solidification during High-Speed Twin-Roll Strip Casting of Al-33 wt pct Cu

    NASA Astrophysics Data System (ADS)

    Sahoo, Seshadev; Kumar, Amitesh; Dhindaw, B. K.; Ghosh, Sudipto

    2012-08-01

    The numerical modeling of heat transfer and solidification during twin-roll strip casting involves incorporating fluid flow, heat transfer, and phase change in the liquid metals and knowledge of heat flux distribution at the liquid metal-roll interface. Although efforts have been put in the development of comprehensive modeling of the process simulation of the heat transfer, solidification during high-speed twin-roll casting and its experimental validation has not been attempted. In the current paper, the results of simulation of twin-roll strip casting up to high speeds has been reported for Al-33 wt pct Cu using FLUENT 6.3.16 (ANSYS, Inc., Canonsburg, PA). Further Jackson-Hunt plot for Al-33 wt pct Cu has been used to validate the simulation. It has been shown by simulation as well as experiment that high speed twin-roll casting can be a method for direct production of layered materials.

  3. Effect of Crucible Diameter Reduction on the Convection, Macrosegregation, and Dendritic Morphology during Directional Solidification of Pb-2.2 Wt Pct Sb Alloy

    NASA Technical Reports Server (NTRS)

    Chen, Jun; Tewari, S. N.; Magadi, G.; DeGroh, H. C., III

    2003-01-01

    The Pb-2.2 wt pct Sb alloy has been directionally solidified in 1-, 2-, 3-, and 7-mm-diameter crucibles with planar and dendritic liquid-solid interface orphology. For plane front solidification, the experimentally observed macrosegregation along the solidified length follows the relationship proposed by Favier. Application of a 0.4 T transverse magnetic field has no effect on the extent of convection. Reducing the ampoule diameter appears to decrease the extent of convection. However, extensive convection is still present even in the 1-mm-diameter crucible. An extrapolation of the observed behavior indicated that nearly diffusive transport conditions require ampoules that are about 40 microns in diameter. Reduction of the crucible diameter does not appear to have any significant effect on the primary dendrite spacing. However, it results in considerable distortion of the dendrite morphology and ordering. This is especially true for the 1-mm diameter samples.

  4. Evolution of Microstructure and Stress Corrosion Cracking Behavior of AA2219 Plate to Ring Weld Joints in 3.5 Wt Pct NaCl Solution

    NASA Astrophysics Data System (ADS)

    Venugopal, A.; Narayanan, P. Ramesh; Sharma, S. C.

    2016-04-01

    AA2219 aluminum alloy plate (T87) and ring (T851) were joined by tungsten inert gas (TIG) welding using multi-pass welding. The mechanical properties and stress corrosion cracking (SCC) resistance of the above base metals (BMs) in different directions (L, LT, and ST) were examined. Similarly, the weld metal joined by plate to plate and plate to ring (PR) joints was evaluated. The results revealed that the mechanical properties of the ring were comparatively lower than the plate. This was found to be due to the extremely coarse grain size of the ring along with severe Cu-rich segregation along the grain boundaries when compared to the plate material. The SCC resistance of the base and weldments were found to be good and not susceptible to SCC. This was shown to be due to high values of SCC index (>0.9) and the typical ductile cracking morphology of the BM and the weld joints after SCC test in the environment (3.5 wt pct NaCl) when compared to test performed in the control environment (air). However, the corrosion resistance of the weld interface between the FZ and ring was inferior to the FZ-plate interface.

  5. Stress Corrosion Cracking Behavior of Multipass TIG-Welded AA2219 Aluminum Alloy in 3.5 wt pct NaCl Solution

    NASA Astrophysics Data System (ADS)

    Venugopal, A.; Sreekumar, K.; Raja, V. S.

    2012-09-01

    The stress corrosion cracking (SCC) behavior of the AA2219 aluminum alloy in the single-pass (SP) and multipass (MP) welded conditions was examined and compared with that of the base metal (BM) in 3.5 wt pct NaCl solution using a slow-strain-rate technique (SSRT). The reduction in ductility was used as a parameter to evaluate the SCC susceptibility of both the BM and welded joints. The results showed that the ductility ratio ( ɛ NaCl/( ɛ air) was 0.97 and 0.96, respectively, for the BM and MP welded joint, and the same was marginally reduced to 0.9 for the SP welded joint. The fractographic examination of the failed samples revealed a typical ductile cracking morphology for all the base and welded joints, indicating the good environmental cracking resistance of this alloy under all welded conditions. To understand the decrease in the ductility of the SP welded joint, preexposure SSRT followed by microstructural observations were made, which showed that the decrease in ductility ratio of the SP welded joint was caused by the electrochemical pitting that assisted the nucleation of cracks in the form of corrosion induced mechanical cracking rather than true SCC failure of the alloy. The microstructural examination and polarization tests demonstrated a clear grain boundary (GB) sensitization of the PMZ, resulting in severe galvanic corrosion of the SP weld joint, which initiated the necessary conditions for the localized corrosion and cracking along the PMZ. The absence of PMZ and a refined fusion zone (FZ) structure because of the lesser heat input and postweld heating effect improved the galvanic corrosion resistance of the MP welded joint greatly, and thus, failure occurred along the FZ.

  6. Analysis of Slip Activity and Deformation Modes in Tension and Tension-Creep Tests of Cast Mg-10Gd-3Y-0.5Zr (Wt Pct) at Elevated Temperatures Using In Situ SEM Experiments

    NASA Astrophysics Data System (ADS)

    Wang, Huan; Boehlert, Carl J.; Wang, Qudong; Yin, Dongdi; Ding, Wenjiang

    2016-05-01

    The tension and tension-creep deformation behavior at elevated temperatures of a cast Mg-10Gd-3Y-0.5Zr (wt pct, GW103) alloy was investigated using in situ scanning electron microscopy. The tests were performed at temperatures ranging from 473 K to 598 K (200 °C to 325 °C). The active slip systems were identified using an EBSD-based slip trace analysis methodology. The results showed that for all of the tests, basal slip was the most likely system to be activated, and non-basal slip was activated to some extent depending on the temperature. No twinning was observed. For the tension tests, non-basal slip consisted of ~35 pct of the deformation modes at low temperatures (473 K and 523 K (200 °C and 250 °C)), while non-basal slip accounted for 12 and 7 pct of the deformation modes at high temperatures (573 K and 598 K (300 °C and 325 °C)), respectively. For the tension-creep tests, non-basal slip accounted for 31 pct of the total slip systems at low temperatures, while this value decreased to 10 to 16 pct at high temperatures. For a given temperature, the relative activity for prismatic slip in the tension-creep tests was slightly greater than that for the tension tests, while the activity for pyramidal slip was lower. Slip-transfer in neighboring grains was observed for the low-temperature tests. Intergranular cracking was the main cracking mode, while some intragranular cracks were observed for the tension-creep tests at high temperature and low stress. Grain boundary ledges were prevalently observed for both the tension and tension-creep tests at high temperatures, which suggests that besides dislocation slip, grain boundary sliding also contributed to the deformation.

  7. The Effect of Nd on the Tension and Compression Deformation Behavior of Extruded Mg-1Mn (wt pct) at Temperatures Between 298 K and 523 K (25 °C and 250 °C)

    NASA Astrophysics Data System (ADS)

    Chakkedath, Ajith; Bohlen, Jan; Yi, Sangbong; Letzig, Dietmar; Chen, Zhe; Boehlert, Carl J.

    2014-07-01

    The tension and compression deformation behavior of extruded magnesium-1 wt pct manganese alloys with nominally 0.3 wt pct (MN10) and 1 wt pct neodymium (MN11) was studied over the temperature range of 298 K to 523 K (25 °C to 250 °C). Nd additions to Mg alloys tend to reduce the strong basal texture exhibited by conventional wrought Mg alloys and this work was intended to study the effect of Nd on the deformation behavior of Mg alloys. In situ tensile and compressive experiments were performed using a scanning electron microscopy, and electron backscatter diffraction was performed both before and after the deformation. A slip trace analysis technique was used to identify the distribution of the deformation systems as a function of strain, and based on this analysis and the texture of the undeformed samples, the critical resolved shear stress ratios between the deformation systems were estimated. In the case of MN11, the deformation behavior under tension at all temperatures was dominated by slip, while in compression, extension twinning was the major deformation mode. In tension at 323 K (50 °C), extension twinning, basal, prismatic < a>, and pyramidal < c + a> slip were active in MN11. Much less extension twinning was observed at 423 K (150 °C), while basal slip and prismatic < a> slip were dominant and presented similar relative activities. At 523 K (250 °C), twinning was not observed, and basal slip controlled the deformation. With the reduction of Nd content, less slip deformation and more twinning were observed during the tensile deformation. However, like for MN11, the extent of twinning in MN10 decreased with increasing temperature and basal slip was the primary deformation mode at elevated temperatures. Extension twinning was the major deformation mode under compression for all test temperatures in MN10 and MN11. The tensile strength decreased with increasing temperature for both alloys, where MN10 was slightly stronger than MN11 at 323 K (50

  8. Retardation of the Cu5Zn8 Phase Fracture and Improvement of Shear Strength of the Sn-9 wt pct Zn/Cu Interface by Inserting an Electroless Palladium Layer

    NASA Astrophysics Data System (ADS)

    Lee, Po-Hsun; Lin, Chi-Pu; Chen, Chih-Ming

    2013-01-01

    A uniform layer of the Cu5Zn8 phase is formed at the Sn-9 wt pct Zn (Sn-9Zn)/Cu interface after reflow at 503 K (230 °C) but fractures very severely during subsequent solid-state aging at 443 K (170 °C). Such a severe fracture of an interfacial intermetallic compound deteriorates the integrity of joint interface and leads to excessive atomic interdiffusion as well as intermetallic compound growth. In the current study, it was observed that by inserting an electroless palladium (Pd) layer at the Sn-9Zn/Cu interface, a Pd2Zn9 phase is formed between Cu5Zn8 and Sn-9Zn solders. This Pd2Zn9 phase exhibits higher microstructural stability at the interface during solid-state aging and effectively retards the fracture of the Cu5Zn8 phase. The integrity of the Sn-9Zn/Cu interface is improved remarkably. Mechanical tests reveal that the shear strength of the Sn-9Zn/Cu joint is enhanced by inserting an electroless Pd layer at the interface.

  9. High-resolution transmission electron microscopy investigation of the face-centered cubic/hexagonal close-packed martensite transformation in Co-31.8 wt pct Ni alloy: Part 2. Plate intersections, extended defects, and nucleation mechanisms

    NASA Astrophysics Data System (ADS)

    Bray, D. W.; Howe, J. M.

    1996-11-01

    The face-centered cubic/hexagonal close-packed (fcc/hcp) martensite phase transformation in a Co-31.8 wt pct Ni alloy was studied by high-resolution transmission electron microscopy (HRTEM). The HRTEM was used to study the structure and properties of intersections between martensite plates and other defects observed in the alloy such as stacking fault tetrahedra (SFT) and Z-type defects. The HRTEM was also used to attempt to determine if various proposed mechanisms for the fcc/hcp martensite transformation were operating. There is evidence to suggest that the reflection mechanism proposed by Bollmann and the dipole mechanism proposed by Hirth are active in the fcc/hcp martensitic transformation, although the evidence is not completely certain in either case. Growth of the hcp phase by a four- or six-plane mechanism as proposed by Mahajan et al. is possible in theory but was not observed in this study. Transformation by previously proposed pole mechanisms was also not observed in this study, although evidence for a new type of pole mechanism was found. The formation of SFT along the fcc/hcp martensite interface was observed to occur by the cross-slip of Shockley partial dislocations out of the fcc/hcp interface onto conjugate fcc matrix planes, followed by further cross-slip to form the SFT, as previously observed for grain boundaries in fcc alloys.

  10. Diffusional Interaction Between U-10 wt pct Zr and Fe at 903 K, 923 K, and 953 K (630 °C, 650 °C, and 680 °C)

    NASA Astrophysics Data System (ADS)

    Park, Y.; Huang, K.; Paz y Puente, A.; LEE, H. S.; Sencer, B. H.; Kennedy, J. R.; Sohn, Y. H.

    2015-01-01

    U-Zr metallic fuels cladded in Fe-alloys are being considered for application in an advanced sodium-cooled fast reactor that can recycle the U-Zr fuels and minimize the long-lived actinide waste. To understand the complex fuel-cladding chemical interaction between the U-Zr metallic fuels with Fe-alloys, a systematic multicomponent diffusion study was carried out using solid-to-solid diffusion couples. The U-10 wt pct Zr vs pure Fe diffusion couples were assembled and annealed at temperatures, 903 K, 923 K, and 953 K (630 °C, 650 °C, and 680 °C) for 96 hours. Development of microstructure, phase constituents, and compositions developed during the thermal anneals were examined by scanning electron microscopy, transmission electron microscopy, and X-ray energy dispersive spectroscopy. Complex microstructure consisting of several layers that include phases such as U6Fe, UFe2, ZrFe2, α-U, β-U, Zr-precipitates, χ, ɛ, and λ were observed. Multi-phase layers were grouped based on phase constituents and microstructure, and the layer thicknesses were measured to calculate the growth constant and activation energy. The local average compositions through the interaction layer were systematically determined, and employed to construct semi-quantitative diffusion paths on isothermal U-Zr-Fe ternary phase diagrams at respective temperatures. The diffusion paths were examined to qualitatively estimate the diffusional behavior of individual components and their interactions. Furthermore, selected area electron diffraction analyses were carried out to determine, for the first time, the exact crystal structure and composition of χ, ɛ, and λ-phases. The χ, ɛ, and λ-phases were identified as Pnma(62) Fe(Zr,U), I4/ mcm(140) Fe(Zr,U)2, and P42/ mnm(136) U3(Zr,Fe), respectively.

  11. Corrosion Behavior of Alloy 625 in PbSO4-Pb3O4-PbCl2-ZnO-10 Wt Pct CdO Molten Salt Medium

    NASA Astrophysics Data System (ADS)

    Mohammadi Zahrani, E.; Alfantazi, A. M.

    2012-08-01

    Corrosion behavior and degradation mechanisms of alloy 625 under a 47.288 PbSO4-12.776 Pb3O4-6.844PbCl2-23.108ZnO-10CdO (wt pct) molten salt mixture under air atmosphere were studied at 873 K, 973 K, and 1073 K (600 °C, 700 °C, and 800 °C). Electrochemical impedance spectroscopy (EIS), open circuit potential (OCP) measurements, and potentiodynamic polarization techniques were used to evaluate the degradation mechanisms and characterize the corrosion behavior of the alloy. Morphology, chemical composition, and phase structure of the corrosion products and surface layers of the corroded specimens were studied by scanning electron microscopy/energy-dispersive X-ray (SEM/EDX) and X-ray map analyses. Results confirmed that during the exposure of alloy 625 to the molten salt, chromium was mainly dissolved through an active oxidation process as CrO3, Cr2O3, and CrNbO4, while nickel dissolved only as NiO in the system. Formation of a porous and nonprotective oxide layer with low resistance is responsible for the weak protective properties of the barrier layer at high temperatures of 973 K and 1073 K (700 °C and 800 °C). There were two kinds of attack for INCONEL 625, including general surface corrosion and pitting. Pitting corrosion occurred due to the breakdown of the initial oxide layer by molten salt dissolution of the oxide or oxide cracking.

  12. A study of the influence of mischmetal additions to Al-7Si-0.3Mg (LM 25/356) alloy

    SciTech Connect

    Ravi, M.; Pillai, U.T.S.; Damodaran, A.D.; Dwarakadasa, E.S.

    1996-05-01

    This article deals with the effect of 0.25-1.5 wt pct mischmetal (MM) addition on the mechanical properties, microstructure, electrical conductivity, and fracture behavior of cast Al-7Si-0.3Mg (LM 25/356) alloy. Modification of eutectic silicon by MM is compared with strontium modification in terms of microstructure, mechanical properties, and fading behavior. Loss of magnesium encountered on holding the molten alloy and its resultant effect on mechanical properties of alloys modified with MM and Sr are compared with those in the unmodified alloy.

  13. Analysis of the Deformation Behavior in Tension and Tension-Creep of Ti-3Al-2.5V (wt pct) at 296 K and 728 K (23 °C and 455 °C) Using In Situ SEM Experiments

    NASA Astrophysics Data System (ADS)

    Li, Hongmei; Boehlert, Carl J.; Bieler, Thomas R.; Crimp, Martin A.

    2014-12-01

    The deformation behavior of a Ti-3Al-2.5V (wt pct) near-α alloy was investigated during in situ deformation inside a scanning electron microscopy (SEM). Two plates with distinct textures were examined. Tensile experiments were performed at 296 K and 728 K (455 °C) (~0.4 T m), while a tensile-creep experiment was performed at 728 K (455 °C) and 180 MPa ( σ/ σ ys = 0.72). The active deformation systems were identified in the α phase using electron backscattered diffraction based slip-trace analysis and SEM images of the surface. Prismatic slip deformation was the dominant slip mode observed for all the experiments in both plates, which was supported by a critical resolved shear stress (CRSS) ratio analysis. However, due to the texture of plate 1, which strongly favored the activation of prismatic slip, the percentages of prismatic slip activity for specimens from plate 1 tested at 296 K and 728 K (23 °C and 455 °C) were higher than the specimens from plate 2 under the same testing conditions. T1 twinning was an active deformation mode at both 296 K and 728 K (23 °C and 455 °C), but the extent of twinning activity decreased with increased temperature. T1 twinning was more frequently observed in specimens from plate 2, which exhibited a higher fraction of twinning systems favoring activation at both 296 K and 728 K (23 °C and 455 °C). The tension-creep experiment revealed less slip and more grain boundary sliding than in the higher strain rate tensile experiments. Using a previously demonstrated bootstrapping statistical analysis methodology, the relative CRSS ratios of prismatic, pyramidal < a>, pyramidal < c+ a>, and T1 twinning deformation systems compared with basal slip were calculated and discussed in light of similar measurements made on CP Ti and Ti-5Al-2.5Sn (wt pct).

  14. Porphyria Cutanea Tarda (PCT)

    MedlinePlus

    ... of UROD in the liver. Hemochromatosis, an iron overload disorder, also can predispose individuals to PCT. Symptoms ... centers regardless of whether there is confirmed iron overload. A phlebotomy is a simple and safe procedure ...

  15. Calorimetric Investigation of Thermal Stability of 304H Cu (Fe-17.7Cr-9.3Ni-2.95Cu-0.91Mn-0.58Nb-0.24Si-0.1C-0.12N-Wt Pct) Austenitic Stainless Steel

    NASA Astrophysics Data System (ADS)

    Tripathy, Haraprasanna; Subramanian, Raju; Hajra, Raj Narayan; Rai, Arun Kumar; Rengachari, Mythili; Saibaba, Saroja; Jayakumar, Tammana

    2016-05-01

    The sequence of phase instabilities that take place in a Fe-17.7Cr-9.3Ni-0.58Nb-2.95Cu-0.12N (wt pct) austenitic stainless steel (304H Cu grade) as a function of temperature has been investigated using dynamic calorimetry. The results obtained from this investigation are supplemented by Thermocalc-based equilibrium and Scheil-Gulliver nonequilibrium solidification simulation. The following phase transformation sequence is found upon slow cooling from liquid: L → L + γ → L + γ + MX → γ + MX + δ → γ +MX + M23C6 → γ + MX + M23C6 + Cu. Under slow cooling, the solidification follows austenite + ferrite (AF) mode, which is in accordance with Thermocalc prediction and Scheil-Gulliver simulation. However, higher cooling rates result in skeletal δ-ferrite formation, due to increased segregation tendency of Nb and Cr to segregate to interdendritic liquid. The solidification mode is found to depend on combined Nb + Cu content. Experimental estimates of enthalpy change associated with melting and secondary phase precipitation are also obtained. In addition a semi-quantitative study on the dissolution kinetics of M23C6 type carbides has also been investigated. The standard solution treatment at 1413 K (1140 °C) is found to be adequate to dissolve both Cu and M23C6 into γ-austenite; but the complete dissolution of MX type carbonitrides occurs near the melting region.

  16. PCT funding. Beggars belief.

    PubMed

    Hacking, John

    2003-04-10

    At the pace of change set for implementing the new PCT funding formula over the next three years, it will take more than 20 years to achieve equity. If the minimum increases were set lower it would largely be achieved within five years. The current state of affairs perpetuates the north-south health divide. PMID:12705085

  17. Fatigue and fracture behavior of U-6 wt. pct. Nb

    SciTech Connect

    Strum, M.J.; Freeman, D.C.; Elmer, J.W.

    1993-05-21

    The fatigue and fracture properties of U6Nb were measured to provide the materials property data needed for structural designs in material processed by solution quenching and aging 200 C/2h. Limited testing was also performed on as-quenched U6Nb. The authors have extended the database on fatigue properties in U6Nb to include both crack initiation data and crack propagation data. The static load carrying capabilities have been characterized through fracture toughness and tensile property measurements. Using a rotating beam fatigue machine, a fatigue strength of 248 MPa was measured at 10{sup 8} cycles for smooth bars at zero mean load. As is typical of nonferrous alloys, U6Nb does not exhibit a fatigue endurance limit. Reductions in fatigue strength for notched bars and for mean loads of 276 MPa and 483 MPa (70 ksi) were also determined. The predominant sites for fatigue crack initiation were identified as niobium carbide and uranium oxide inclusion clusters and the distribution of these inclusions are presented. Fatigue crack propagation rates were measured in the near-threshold regime using compact tension specimens. The fatigue threshold for crack growth rates below 10{sup {minus}7} mm/cycle were measured at both R = 0.1, for which a fatigue threshold of 3.2 MPa{radical}m was measured, and for constant Kmax cycles with Kmax values of 14.6 MPa{radical}m and 30.5 MPa{radical}m, for which the fatigue threshold was reduced to 0.9 MPa{radical} and 0.6 MPa{radical}m, respectively.

  18. Microstructure of Precipitation Hardenable Powder Metallurgical Ni Alloys Containing 35 to 45 pct Cr and 3.5 to 6 pct Nb

    NASA Astrophysics Data System (ADS)

    Bihlet, Uffe D.; Dahl, Kristian V.; Somers, Marcel A. J.

    2014-10-01

    Ni-based alloys with high Cr contents are not only known for their excellent high temperature and hot corrosion resistance, but are also known for poor mechanical properties and difficult workability. Powder metallurgical (PM) manufacturing of alloys may overcome several of the shortcomings encountered in materials manufacturing involving solidification. In the present work, six PM Ni-based alloys containing 35 to 45 wt pct Cr and 3.5 to 6 wt pct Nb were produced and compacted via hot isostatic pressing. Samples were heat treated for up to 1656 hours at either 923 K or 973 K (650 °C or 700 °C), and the microstructures and mechanical properties were quantified and compared to thermodynamic calculations. For the majority of the investigated alloys, the high Cr and Nb contents caused development of primary populations of globular α-Cr and δ (Ni3Nb). Transmission electron microscopy of selected alloys confirmed the additional presence of metastable γ″ (Ni3Nb). A co-dependent growth morphology was found, where the preferred growth direction of γ″, the {001} planes of γ-Ni, caused precipitates of both α-Cr and δ to appear in the form of mutually perpendicular oriented disks or plates. Solution heat treatment at 1373 K (1100 °C) followed by aging at 973 K (700 °C) produced a significant strength increase for all alloys, and an aged yield strength of 990 MPa combined with an elongation of 21 pct is documented for Ni 40 wt pct Cr 3.5 wt pct Nb.

  19. PbO reduction and crucible reactions of 70 wt pct PbO-30 wt pct B2O3 glass

    NASA Technical Reports Server (NTRS)

    Schilling, Christopher H.; Lee, Mark C.

    1987-01-01

    NASA has conducted an investigation of PbO-B2O3 glass with a view to PbO reduction and subsequent crucible reactions as a function of temperature and oxygen partial pressure, in order to establish the optimum processing conditions for subcentimetric glass hollow spheres applicable to inertial confinement fusion targets. The results obtained support the selection of appropriate crucible materials and oxygen partial pressure-temperature combinations that avoid phase separation from PbO reduction and/or crucible reactions.

  20. Damping Capacities of Mg-4 Pct Zn-(0-0.5) Pct Ca Biomedical Alloys

    NASA Astrophysics Data System (ADS)

    Jun, Joong-Hwan; Hwang, In-Je

    2016-07-01

    This study is intended to investigate the damping capacities of cast Mg-4 pct Zn-(0-0.5) pct Ca biomedical alloys. The Mg-4 pct Zn-(0-0.5) pct Ca alloys had similar damping levels regardless of Ca content in the strain-amplitude-independent region, but showed a decreasing tendency with an increase in Ca content in the strain-amplitude-dependent region. Almost identical concentration of solutes in the α-(Mg) matrix and the increased number density of the precipitate particles are responsible for the damping behaviors in the strain-amplitude-independent and strain-amplitude-dependent regions, respectively.

  1. Effect of environment on fracture toughness of 96 wt pct alumina

    NASA Technical Reports Server (NTRS)

    Choi, Sung R.; Tikare, Veena; Salem, Jonathan A.

    1993-01-01

    An effort is made to deepen understanding of environmental effects on the fracture toughness of an alumina composition that contains a residual glassy phase, by ascertaining the fracture toughness under atmospheric conditions in such varied environments as air distilled water, silicone oil, and liquid nitrogen. Fracture toughness was determined via the single-edge-precracked beam technique. Weibull strength parameters are compared for polished specimens tested both in air and silicone environments.

  2. Radial macrosegregation and dendrite clustering in directionally solidified Al-7Si and Al-19Cu alloys

    NASA Astrophysics Data System (ADS)

    Ghods, M.; Johnson, L.; Lauer, M.; Grugel, R. N.; Tewari, S. N.; Poirier, D. R.

    2016-05-01

    Hypoeutectic Al-7 wt% Si and Al-19 wt% Cu alloys were directionally solidified upward in a Bridgman furnace through a range of constant growth speeds and thermal gradients. Though processing is thermo-solutally stable, flow initiated by gravity-independent advection at, slightly leading, central dendrites moves rejected solute out ahead and across the advancing interface. Here any lagging dendrites are further suppressed which promotes a curved solid-liquid interface and the eventual dendrite "clustering" seen in transverse sections (dendrite "steepling" in longitudinal orientations) as well as extensive radial macrosegregation. Both aluminum alloys showed considerable macrosegregation at the low growth speeds (10 and 30 μm s-1) but not at higher speed (72 μm s-1). Distribution of the fraction eutectic-constituent on transverse sections was determined in order to quantitatively describe radial macrosegregation. The convective mechanisms leading to dendrite-steepling were elucidated with numerical simulations, and their results compared with the experimental observations.

  3. The effect of Sr and Fe additions on the microstructure and mechanical properties of a direct squeeze cast Al-7Si-0.3Mg alloy

    SciTech Connect

    Dong, J.X.; Karnezis, P.A.; Durrant, G.; Cantor, B.

    1999-05-01

    This article describes the results of an investigation into the microstructure and mechanical properties of a gravity die cast and direct squeeze cast LM25 alloy (Al-7Si-0.3Mg-0.3Fe). The direct squeeze cast LM25 alloy has superior mechanical properties compared to the gravity die cast LM25 alloy, especially with regard to ductility, which is increased from {approximately}1.7 pct for the gravity die cast LM25 alloy to {approximately}8.0 pct for the direct squeeze cast LM25 alloy in the T6 heat-treated conditions. This increase in ductility is due to (1) the removal of porosity, (2) a decrease in Si particle size, and (3) a refinement of the Fe-Si-aluminide particles. High cooling rates in direct squeeze casting result in quench modification of the Si particles, such that chemical modification with Sr or Na may not be required. In addition, direct squeeze casting is more tolerant of Fe impurities in the alloy, due to the formation of smaller Fe-Si-aluminide particles than those in gravity die cast material. The direct squeeze cast LM25 + Fe alloy (Al-7Si-0.3Mg-1.0Fe) has a ductility of {approximately}6.5 pct, compared to that of {approximately}0.5 pct for the gravity die cast LM25 + Fe alloy in the T6 heat-treated condition. This increase in tolerance to Fe impurities can lead to a substantial reduction in manufacturing costs due to (1) reduced raw-material costs, (2) reduced die sticking, and (3) improved die life.

  4. The effect of Sr and Fe additions on the microstructure and mechanical properties of a direct squeeze cast Al-7Si-0.3Mg alloy

    NASA Astrophysics Data System (ADS)

    Dong, J. X.; Karnezis, P. A.; Durrant, G.; Cantor, B.

    1999-05-01

    This article describes the results of an investigation into the microstructure and mechanical properties of a gravity die cast and direct squeeze cast LM25 alloy (Al-7Si-0.3Mg-0.3Fe). The direct squeeze cast LM25 alloy has superior mechanical properties compared to the gravity die cast LM25 alloy, especially with regard to ductility, which is increased from ˜1.7 pct for the gravity die cast LM25 alloy to ˜8.0 pct for the direct squeeze cast LM25 alloy in the T6 heat-treated condition. This increase in ductility is due to (1) the removal of porosity, (2) a decrease in Si particle size, and (3) a refinement of the Fe-Si-aluminide particles. High cooling rates in direct squeeze casting result in quench modification of the Si particles, such that chemical modification with Sr or Na may not be required. In addition, direct squeeze casting is more tolerant of Fe impurities in the alloy, due to the formation of smaller Fe-Si-aluminide particles than those in gravity die cast material. The direct squeeze cast LM25+Fe alloy (Al-7Si-0.3Mg-1.0Fe) has a ductility of ˜6.5 pct, compared to that of ˜0.5 pct for the gravity die cast LM25 + Fe alloy in the T6 heat-treated condition. This increase in tolerance to Fe impurities can lead to a substantial reduction in manufacturing costs due to (1) reduced raw-material costs, (2) reduced die sticking, and (3) improved die life.

  5. Macrosegregation in Al-7Si alloy caused by abrupt cross-section change during directional solidification

    NASA Astrophysics Data System (ADS)

    Ghods, M.; Johnson, L.; Lauer, M.; Grugel, R. N.; Tewari, S. N.; Poirier, D. R.

    2016-09-01

    Hypoeutectic Al-7 wt .% Si alloys were directionally solidified vertically downward in cylindrical molds that incorporated an abrupt cross-section decrease (9.5 mm to 3.2 mm diameter) which, after 5 cm, reverted back to 9.5 mm diameter in a Bridgman furnace; two constant growth speeds and thermal gradients were investigated. Thermosolutal convection and cross-section-change-induced shrinkage flow effects on macrosegregation were investigated. Dendrite clustering and extensive radial macrosegregation was seen, particularly in the larger cross-sections, before contraction and after expansion, this more evident at the lower growth speed. This alloy shows positive longitudinal macrosegregation near cross-section decrease followed by negative macrosegregation right after it; the extent of macrosegregation, however, decreases with increasing growth speed. Primary dendrite steepling intensified as solidification proceeded into the narrower section and negative longitudinal macrosegregation was seen on the re-entrant shelves at expansion. A two-dimensional model accounting for both shrinkage and thermo-solutal convection was used to simulate solidification and the resulting mushy-zone steepling and macrosegregation. The experimentally observed longitudinal and radial macrosegregation associated with the cross-section changes during directional solidification of an Al-7Si alloy is well captured by the numerical simulations.

  6. Primary Dendrite Arm Spacings in Al-7Si Alloy Directionally Solidified on the International Space Station

    NASA Technical Reports Server (NTRS)

    Angart, Samuel; Lauer, Mark; Poirier, David; Tewari, Surendra; Rajamure, Ravi; Grugel, Richard

    2015-01-01

    Samples from directionally solidified Al- 7 wt. % Si have been analyzed for primary dendrite arm spacing (lambda) and radial macrosegregation. The alloy was directionally solidified (DS) aboard the ISS to determine the effect of mitigating convection on lambda and macrosegregation. Samples from terrestrial DS-experiments thermal histories are discussed for comparison. In some experiments, lambda was measured in microstructures that developed during the transition from one speed to another. To represent DS in the presence of no convection, the Hunt-Lu model was used to represent diffusion controlled growth under steady-state conditions. By sectioning cross-sections throughout the entire length of a solidified sample, lambda was measured and calculated using the model. During steady-state, there was reasonable agreement between the measured and calculated lambda's in the space-grown samples. In terrestrial samples, the differences between measured and calculated lambda's indicated that the dendritic growth was influenced by convection.

  7. Dendrite characteristics in directionally solidified Pb-8 pct Au and Pb-3 pct Pd alloys

    NASA Technical Reports Server (NTRS)

    Tewari, S. N.

    1986-01-01

    The dendritic microstructure and solute compression profiles for Pb-8 pct Au and Pb-3 pct Pd alloy samples are examined. Two groups of models, the minimum undercooled dendrite tip model of Burden and Hunt (1974) and Laxmanan (1974, 1984) and marginal stability at the dendrite tip models of Trivedi (1980) and Laxmanan (1974) are used to predict growth behavior of the alloy samples. The experimentally observed dendrite tip radius, primary arm spacing, and liquid composition at the dendrite tip are compared with theoretical predictions. It is observed that the modified minimum undercooling dendrite tip model and both of the marginal stability models accurately predict dendritic behavior. It is concluded that quantitative comparison of the primary arm spacing measurements can not form the basis for distinguishing among the various dendrite growth models in a positive temperature gradient.

  8. Dendrite characteristics in directionally solidified Pb-8 pct Au and Pb-3 pct Pd alloys

    NASA Technical Reports Server (NTRS)

    Tewari, S. N.

    1986-01-01

    An investigation of Pb-8 pct Au and Pb-3 pct Pd alloy specimens which have been partially directionally solidified and then quenched is performed in order to characterize their dendritic microstructural details and solute composition profiles. A controlled sectioning technique is employed to measure dendrite tip radii. It is found that most of the observed behavior is predicted quite well by a modification of the Burden and Hunt (1974) model proposed by Laxmanan (1984), in addition to the models based on the marginal stability approach. Results indicate that quantitative comparison of the primary arm spacing measurements can not form the basis of distinguishing among the various dendrite growth models in a positive temperature gradient.

  9. Mechanical Properties and Strengthening Mechanisms of Al-15 Pct B4C Composites with Sc and Zr at Elevated Temperatures

    NASA Astrophysics Data System (ADS)

    Qin, Jian; Zhang, Zhan; Chen, X.-Grant

    2016-09-01

    The mechanical properties at ambient and elevated temperatures of two Al-15 vol pct B4C composites, S40 with 0.4 wt pct Sc and SZ40 with 0.4 wt pct Sc and 0.24 wt pct Zr, are investigated during long-term thermal annealing. The presence of large B4C particles in the microscale has a moderate but stable strengthening effect on Al-B4C composites at ambient and elevated temperatures, while the precipitation of nanoscale Al3Sc and Al3(Sc, Zr) in the composite matrix provides a predominate contribution to the composite strength, which is varied by tested temperatures. The Al3Sc precipitates in S40 remain coarsening resistant at 523 K (250 °C), whereas the Al3(Sc, Zr) precipitates in SZ40 are thermally stable at 573 K (300 °C) over 2000 hours of annealing. At higher annealing temperatures (573 K (300 °C) for S40 and 623 K (350 °C) for SZ40), both Al3Sc and Al3(Sc, Zr) precipitates become coarsening with prolonged annealing time. The yield strength of S40 and SZ40 at ambient temperature decreases with the increasing precipitate size, which can be explained by the classical precipitate shearing and Orowan bypass mechanisms. At elevated temperatures [523 K to 623 K (250 °C to 350 °C)], considerably lower yield stresses are observed compared to those at ambient temperature, which invokes a dislocation climb mechanism. The predicted yield strengths at elevated temperatures by the combination of dislocation climb and Orowan models are in good agreement with the experimental data.

  10. Accelerated glass reaction under PCT conditions

    SciTech Connect

    Ebert, W.L.; Bates, J.K.; Buck, E.C.; Bradley, C.R.

    1992-01-01

    Static leach tests similar to PCT (Product Consistency Test) were performed for up to 2 years to assess long-term reaction behavior of high-level nuclear waste glasses similar to those at Defense Waste Processing Facility. These tests show the reaction rate to decrease with the reaction time from an initially high rate to a low rate, but then to accelerate to a higher rate after reaction times of about 1 year, depending on glass surface area/leachant volume ratio used. Solution concentrations of soluble glass components increase as the reaction is accelerated, while release of other glass components into solution is controlled by secondary phases. Net result is that transformation of glass to stable phases is accelerated while the solution becomes enriched in soluble components not effectively contained in secondary phases. Rate becomes linear in time after the acceleration and may be similar to the initial forward rate. A current model of glass reaction predicts that the glass reaction will be accelerated upon the formation of secondary phases which lower the silicic acid solution concentration. These tests show total Si concentration to increase upon reaction acceleration, however, which may be due to the slightly higher pH attained with the acceleration. The sudden change in the reaction rate is likely due to secondary phase formation. 17 refs, 2 tabs, 3 figs.

  11. Accelerated glass reaction under PCT conditions

    SciTech Connect

    Ebert, W.L.; Bates, J.K.; Buck, E.C.; Bradley, C.R.

    1992-12-31

    Static leach tests similar to PCT (Product Consistency Test) were performed for up to 2 years to assess long-term reaction behavior of high-level nuclear waste glasses similar to those at Defense Waste Processing Facility. These tests show the reaction rate to decrease with the reaction time from an initially high rate to a low rate, but then to accelerate to a higher rate after reaction times of about 1 year, depending on glass surface area/leachant volume ratio used. Solution concentrations of soluble glass components increase as the reaction is accelerated, while release of other glass components into solution is controlled by secondary phases. Net result is that transformation of glass to stable phases is accelerated while the solution becomes enriched in soluble components not effectively contained in secondary phases. Rate becomes linear in time after the acceleration and may be similar to the initial forward rate. A current model of glass reaction predicts that the glass reaction will be accelerated upon the formation of secondary phases which lower the silicic acid solution concentration. These tests show total Si concentration to increase upon reaction acceleration, however, which may be due to the slightly higher pH attained with the acceleration. The sudden change in the reaction rate is likely due to secondary phase formation. 17 refs, 2 tabs, 3 figs.

  12. WT - WIND TUNNEL PERFORMANCE ANALYSIS

    NASA Technical Reports Server (NTRS)

    Viterna, L. A.

    1994-01-01

    WT was developed to calculate fan rotor power requirements and output thrust for a closed loop wind tunnel. The program uses blade element theory to calculate aerodynamic forces along the blade using airfoil lift and drag characteristics at an appropriate blade aspect ratio. A tip loss model is also used which reduces the lift coefficient to zero for the outer three percent of the blade radius. The application of momentum theory is not used to determine the axial velocity at the rotor plane. Unlike a propeller, the wind tunnel rotor is prevented from producing an increase in velocity in the slipstream. Instead, velocities at the rotor plane are used as input. Other input for WT includes rotational speed, rotor geometry, and airfoil characteristics. Inputs for rotor blade geometry include blade radius, hub radius, number of blades, and pitch angle. Airfoil aerodynamic inputs include angle at zero lift coefficient, positive stall angle, drag coefficient at zero lift coefficient, and drag coefficient at stall. WT is written in APL2 using IBM's APL2 interpreter for IBM PC series and compatible computers running MS-DOS. WT requires a CGA or better color monitor for display. It also requires 640K of RAM and MS-DOS v3.1 or later for execution. Both an MS-DOS executable and the source code are provided on the distribution medium. The standard distribution medium for WT is a 5.25 inch 360K MS-DOS format diskette in PKZIP format. The utility to unarchive the files, PKUNZIP, is also included. WT was developed in 1991. APL2 and IBM PC are registered trademarks of International Business Machines Corporation. MS-DOS is a registered trademark of Microsoft Corporation. PKUNZIP is a registered trademark of PKWare, Inc.

  13. Nuclear waste glass product consistency test (PCT), Version 5. 0

    SciTech Connect

    Jantzen, C.M.; Bibler, N.E.; Beam, D.C.; Ramsey, W.G.; Waters, B.J.

    1992-06-01

    Liquid high-level nuclear waste will be immobilized at the Savannah River Site (SRS) by vitrification in borosilicate glass. The glass will be produced in the Defense Waste Processing Facility (DWPF), poured into stainless steel canisters, and eventually disposed of in a geologic repository. In order to comply with the Waste Acceptance Preliminary Specifications (WAPS), the durability of the glass needs to be measured during production to assure its long term stability and radionuclide release properties. A durability test, designated the Produce Consistency Test (PCT), was developed for DWPF glass in order to meet the WAPS requirements. The response of the PCT procedure was based on extensive testing with glasses of widely different compositions. The PCT was determined to be very reproducible, to yield reliable results rapidly, and to be easily performed in shielded cell facilities with radioactive samples. Version 5.0 of the PCT procedure is attached.

  14. The Behaviour of Bifilm Defects in Cast Al-7Si-Mg Alloy.

    PubMed

    El-Sayed, Mahmoud Ahmed

    2016-01-01

    Double oxide films (bifilms) are significant defects in the casting of light alloys, and have been shown to decrease tensile and fatigue properties, and also to increase their scatter, making casting properties unreproducible and unreliable. A bifilm consists of doubled-over oxide films containing a gas-filled crevice and is formed due to surface turbulence of the liquid metal during handling and/or pouring. Previous studies has shown that the nature of oxide film defects may change with time, as the atmosphere inside the bifilm could be consumed by reaction with the surrounding melt, which may enhance the mechanical properties of Al alloy castings. As a proxy for a bifilm, an air bubble was trapped within an Al-7wt.%Si-0.3wt.%Mg (2L99) alloy melt, subjected to stirring. The effect of different parameters such as the holding time, stirring velocity and melt temperature on the change in gas composition of the bubble was investigated, using a design of experiments (DoE) approach. Also, the solid species inside the bubbles solidified in the melt were examined using SEM. The results suggested that both oxygen and nitrogen inside the bifilm would be consumed by reaction with the surrounding melt producing MgAl2O4 and AlN, respectively. Also, hydrogen was suggested to consistently diffuse into the defect. The reaction rates and the rate of H diffusion were shown to increase upon increasing the holding time and temperature, and stirring velocity. Such significant effect of the process parameters studied on the gaseous content of the bubble suggesting that a careful control of such parameters might lead to the deactivation of bifilm defects, or at least elimination of their deteriorous effect in light alloy castings. PMID:27529350

  15. The Behaviour of Bifilm Defects in Cast Al-7Si-Mg Alloy

    PubMed Central

    2016-01-01

    Double oxide films (bifilms) are significant defects in the casting of light alloys, and have been shown to decrease tensile and fatigue properties, and also to increase their scatter, making casting properties unreproducible and unreliable. A bifilm consists of doubled-over oxide films containing a gas-filled crevice and is formed due to surface turbulence of the liquid metal during handling and/or pouring. Previous studies has shown that the nature of oxide film defects may change with time, as the atmosphere inside the bifilm could be consumed by reaction with the surrounding melt, which may enhance the mechanical properties of Al alloy castings. As a proxy for a bifilm, an air bubble was trapped within an Al-7wt.%Si-0.3wt.%Mg (2L99) alloy melt, subjected to stirring. The effect of different parameters such as the holding time, stirring velocity and melt temperature on the change in gas composition of the bubble was investigated, using a design of experiments (DoE) approach. Also, the solid species inside the bubbles solidified in the melt were examined using SEM. The results suggested that both oxygen and nitrogen inside the bifilm would be consumed by reaction with the surrounding melt producing MgAl2O4 and AlN, respectively. Also, hydrogen was suggested to consistently diffuse into the defect. The reaction rates and the rate of H diffusion were shown to increase upon increasing the holding time and temperature, and stirring velocity. Such significant effect of the process parameters studied on the gaseous content of the bubble suggesting that a careful control of such parameters might lead to the deactivation of bifilm defects, or at least elimination of their deteriorous effect in light alloy castings. PMID:27529350

  16. Compared production behavior of borax and unborax premixed SiC reinforcement Al7Si-Mg-TiB alloys composites with semi-solid stir casting method

    NASA Astrophysics Data System (ADS)

    Haryono, M. B.; Sulardjaka, Nugroho, Sri

    2016-04-01

    The present study was aimed to investigate the effect of borax additive on physical and mechanical properties of Al7Si-Mg-TiB with the reinforcement of silicon carbide. In this case, the different weight percentage from the reinforcement of SiC (10, 15, and 20% wt), and the borax additive (ratio 1:4) were homogenously added into the matrix by employing the semi-solid stir casting method at the temperature of 590°C. Al7Si-Mg-TiB melted in an electric resistance furnace at 800°C for 25 minutes and the holding time of 5 minutes; SiC was stirred with borax inside the chamber and heated at the temperature of 250°C for 25 minutes. Then, it melted by lowing the temperature into 590°C. The SiC-borax mixture was added into the electric resistance furnace, and automatically stirred by the stirrer at a constant speed (500 rpm for 3 minutes) in the composite A17Si-Mg-TiB. It melted when heated at 750°C for 17minutes,then, casting was performed on the prepared mould. The characterizations of Al7Si-Mg-TiB-SiC/borax were porosity, hardness, and microstructure on the Al7Si-Mg-TiB-SiC/ borax. The porosity of AMC tended to increase along with the increaseof the wt% SiC (1.4%-3.6%); however, borax additive underwent a decrease in porosity (0.14%-1.3%). Further, hardness tended to improve along with the increase of wt% SiC. The unboraxmixture had 79,6 HRB up to 94 HRB. Whereas, the borax additive mixture had 105,8 HRB up to 121 HRB.

  17. Influence of Heat Treatment on the Microstructure and Corrosion Resistance of 13 Wt Pct Cr-Type Martensitic Stainless Steel

    NASA Astrophysics Data System (ADS)

    Lu, Si-Yuan; Yao, Ke-Fu; Chen, Yun-Bo; Wang, Miao-Hui; Ge, Xue-Yuan

    2015-12-01

    The effect of heat treatment on the microstructure and the electrochemical properties of a typical corrosion-resistant plastic mold steel in Cl--containing solution were studied in this research. Through X-ray diffraction patterns, SEM and TEM analysis, it was found that the sequence of the precipitates in the steels tempered at 573 K, 773 K, and 923 K (300 °C, 500 °C, and 650 °C) was θ-M3C carbides, nano-sized Cr-rich M23C6 carbides, and micro/submicron-sized Cr-rich M23C6 carbides, respectively. The results of the electrochemical experiments showed that the pitting potential of the as-quenched martensitic stainless steels increased with the austenitizing temperature. However, the corrosion resistance of the steels would decreased after tempering, especially when tempered at 773 K (500 °C), no passivation regime could be found in the polarization curve of the MSSs and no effective passive film could be formed on the steels in Cl--containing environments. The present results suggested that the temperature around 773 K (500 °C) should be avoided for tempering process of MSS used as plastic molds.

  18. Resistance Microwelding of Ti-55.8 wt pct Ni Nitinol Wires and the Effects of Pseudoelasticity

    NASA Astrophysics Data System (ADS)

    Tam, Billy; Pequegnat, Andrew; Khan, Mohammad Ibraheem; Zhou, Yunhong

    2012-08-01

    Nitinol has revolutionized many traditional engineering designs with its unique properties that include pseudoelasticity and the shape-memory effect (SME). However, the general lack of understanding on welding Nitinol limits its full potential in practical applications. The current study examined the microstructure and mechanical properties of resistance microwelded (RMW) Ni-rich Nitinol wires at different applied currents. The results revealed a solid-state bonding mechanism that consisted of six main stages, including (1) cold collapse, (2) dynamic recrystallization, (3) interfacial melting, (4) squeeze out, (5) excessive flash, and (6) surface melting. The joint strength and fracture mechanism were linked closely to the metallurgical properties of the welds. Through differential scanning calorimetry (DSC) testing, it was found that the weld metal underwent phase transformation at lower temperatures compared with the base material. Also, the pseudoelastic property of Nitinol was found to have a large effect on the contact resistance during the onset of welding current. Compression tests with varying temperatures confirmed distinct differences in displacement ( i.e., cold collapse) under the welding load of 5 kg-f caused by changes in the thermodynamic stability of the austenite phase. Both the dynamic resistance and displacement measurements were found to be significantly different during the RMW of Nitinol crossed wires compared with welding 316 low-vacuum melted (LVM) stainless steel (SS) crossed wires.

  19. Simulation of Channel Segregation During Directional Solidification of In—75 wt pct Ga. Qualitative Comparison with In Situ Observations

    NASA Astrophysics Data System (ADS)

    Saad, Ali; Gandin, Charles-André; Bellet, Michel; Shevchenko, Natalia; Eckert, Sven

    2015-11-01

    Freckles are common defects in industrial casting. They result from thermosolutal convection due to buoyancy forces generated from density variations in the liquid. The present paper proposes a numerical analysis for the formation of channel segregation using the three-dimensional (3D) cellular automaton (CA)—finite element (FE) model. The model integrates kinetics laws for the nucleation and growth of a microstructure with the solution of the conservation equations for the casting, while introducing an intermediate modeling scale for a direct representation of the envelope of the dendritic grains. Directional solidification of a cuboid cell is studied. Its geometry, the alloy chosen as well as the process parameters are inspired from experimental observations recently reported in the literature. Snapshots of the convective pattern, the solute distribution, and the morphology of the growth front are qualitatively compared. Similitudes are found when considering the coupled 3D CAFE simulations. Limitations of the model to reach direct simulation of the experiments are discussed.

  20. Nuclear waste glass Product Consistency Test (PCT), Version 3. 0

    SciTech Connect

    Jantzen, C.M.; Bibler, N.E.

    1990-11-01

    Liquid high-level nuclear waste will be immobilized at the Savannah River Site (SRS) by vitrification in borosilicate glass. The glass will be produced in the Defense Waste Processing Facility (DWPF), poured into stainless steel canisters, and eventually disposed of in a geologic repository. In order to comply with the Waste Acceptance Preliminary Specifications (WAPS), the durability of the glass needs to be measured during production to assure its long term stability and radionuclide release properties. A durability test, designated the Product Consistency Test (PCT), was developed for DWPF glass in order to meet the WAPS requirements. The response of the PCT procedure was based on extensive testing with glasses of widely different compositions. The PCT was determined to be very reproducible, to yield reliable results rapidly, and to be easily performed in shielded cell facilities with radioactive samples.

  1. Fatigue crack growth rates and fracture toughness of rapidly solidified Al-8. 5 pct Fe-1. 2 pct V-1. 7 pct Si alloys

    SciTech Connect

    Hariprasad, S.; Sastry, S.M.L.; Jerina, K.L. . Mechanical Engineering Dept.); Lederich, R.J. )

    1994-05-01

    The room-temperature fatigue crack growth rates (FCGR) and fracture toughness were evaluated for different crack plane Orientations of an Al-8.5 pct Fe-1.2 pct V-1.7 pct Si alloy produced by planar flow casting (PFC) and atomized melt deposition (AMD) processes. For the alloy produced by the PFC process, properties were determined in six different orientations, including the short transverse directions S-T and S-L. Diffusion bonding and adhesive bonding methods were used to prepare specimens for determining FCGR and fracture toughness in the short transverse direction. Interparticle boundaries control fracture properties in the alloy produced by PFC. Fracture toughness of the PFC alloy varies from 13.4 MPa[radical][bar m] to 30.8 MPa[radical][bar m], depending on the orientation of the crack plane relative to the interparticle boundaries. Fatigue crack growth resistance and fracture toughness are greater in the L-T, L-S, and T-S directions than in the T-L, S-T, and S-L orientations. The alloy produced by AMD does not exhibit anisotropy in fracture toughness and fatigue crack growth resistance in the as-deposited condition or in the extruded condition. The fracture toughness varies from 17.2 MPa[radical][bar m] to 18.5 MPa[radical][bar m] for the as-deposited condition and from 19.8 MPa[radical][bar m] to 21.0 MPa[radical][bar m] for the extruded condition. Fracture properties are controlled by intrinsic factors in the alloy produced by AMD. Fatigue crack growth rates of the AMD alloy are comparable to those of the PFC alloy in the L-T orientation. The crack propagation modes were studied by optical metallographic examination of crack-microstructure interactions and scanning electron microscopy of the fracture surfaces.

  2. Fatigue crack growth rates and fracture toughness of rapidly solidified Al-8.5 pct Fe-1.2 pct V-1.7 pct Si alloys

    NASA Astrophysics Data System (ADS)

    Hariprasad, S.; Sastry, S. M. L.; Jerina, K. L.; Lederich, R. J.

    1994-05-01

    The room-temperature fatigue crack growth rates (FCGR) and fracture toughness were evaluated for different crack plane orientations of an Al-8.5 Pct Fe-1.2 Pct V-1.7 Pct Si alloy produced by planar flow casting (PFC) and atomized melt deposition (AMD) processes. For the alloy produced by the PFC process, properties were determined in six different orientations, including the short transverse directions S-T and S-L. Diffusion bonding and adhesive bonding methods were used to prepare specimens for determining FCGR and fracture toughness in the short transverse direction. Interparticle boundaries control fracture properties in the alloy produced by PFC. Fracture toughness of the PFC alloy varies from 13.4 MPa√m to 30.8 MPa√m, depending on the orientation of the crack plane relative to the interparticle boundaries. Fatigue crack growth resistance and fracture toughness are greater in the L-T, L-S, and T-S directions than in the T-L, S-T, and S-L orientations. The alloy produced by AMD does not exhibit anisotropy in fracture toughness and fatigue crack growth resistance in the as-deposited condition or in the extruded condition. The fracture toughness varies from 17.2 MPa√m to 18.5 MPa√m for the as-deposited condition and from 19.8 MPa√m to 21.0 MPa√m for the extruded condition. Fracture properties are controlled by intrinsic factors in the alloy produced by AMD. Fatigue crack growth rates of the AMD alloy are comparable to those of the PFC alloy in the L-T orientation. The crack propagation modes were studied by optical metallographic examination of crack-microstructure interactions and scanning electron microscopy of the fracture surfaces.

  3. Chemical composition and structural identification of eutectic carbide in 1 pct Mn ductile iron

    NASA Astrophysics Data System (ADS)

    Ahmadabadi, M. Nili; Niyama, E.; Tanino, M.; Abe, T.; Ohide, T.

    1994-05-01

    Manganese, which may be used in ductile cast iron as a potent hardenability promoter, segregates in the intercellular region. This segregation becomes more severe as a consequence of poor inoculation, low cooling rate, or increasing of nominal Mn content in the alloy. In severely Mn-segregated regions, Mn eutectic carbide may be formed, which has a deteriorating effect on the mechanical properties of casting. In this study, a 1 Pct Mn ductile iron was used to investigate the chemical composition and crystal structure of the Mn eutectic carbide by electron microscopy (scanning and transmission), X-ray, and an electron probe microanalyzer (EPMA). Transmission electron microscope (TEM) and X-ray studies show that the crystal structure of carbide is orthorhombic with lattice parameters of a = 14.825, b = 11.415, and c = 8.880 (Å). The concentrations of Mn, Si, and Cr in carbide, analyzed by scanning electron microscope-energy-dispersive X-ray spectrometer (SEM-EDX) and transmission electron microscope-energy-dispersive X-ray spectrometer (TEM-EDX), were 5.0 to 7.0, 0.5 to 2.8 and 1.5 to 2.2 (wt Pct), respectively. The ratio of Fe plus other metal atoms to C was calculated from EPMA experiments to be 2.5-2.9. It was shown that by diminishing Mn segregation, precipitated eutectic carbide can be reduced. It is expected that this can be achieved by reducing nominal content of Mn or by increasing nodule count.

  4. Thermal conductivity of U-20 wt.%Pu-2 wt.%Am-10 wt.%Zr alloy

    NASA Astrophysics Data System (ADS)

    Nishi, Tsuyoshi; Nakajima, Kunihisa; Takano, Masahide; Kurata, Masaki; Arita, Yuji

    2015-09-01

    The authors fabricated U-20 wt.%Pu-2 wt.%Am-10 wt.%Zr alloys and evaluated the heat capacity and thermal conductivity. The heat capacity was measured between 335 and 827 K by a drop calorimetry. The thermal diffusivity was measured between 300 and 1073 K by a laser flash method. The thermal conductivity was evaluated from the measured thermal diffusivity and heat capacity. The thermal conductivity of U-20 wt.%Pu-2 wt.%Am-10 wt.%Zr alloy was slightly higher than literature values of U-Pu-Zr and U-Pu-MA-Zr alloys. The thermal conductivity was formulated for use in practical design for Generation IV fast reactors.

  5. Impact Toughness of 0.2 Pct C-1.5 Pct Si-(1.5 to 5) Pct Mn Transformation-Induced Plasticity-Aided Steels with an Annealed Martensite Matrix

    NASA Astrophysics Data System (ADS)

    Tanino, Hikaru; Horita, Masaomi; Sugimoto, Koh-Ichi

    2016-05-01

    The impact properties of 0.2 pct C-1.5 pct Si-(1.5 to 5) pct Mn transformation-induced plasticity (TRIP)-aided steels with an annealed martensite matrix which had been subjected to isothermal transformation after inter-critical annealing were investigated for potential automotive applications. The impact properties are related to the retained austenite characteristics of the steels. The products of tensile strength (TS) and Charpy impact absorbed value (CIAV) were the same for the 1.5 and 5 pct Mn steels, although the ductile-brittle transition temperature was higher for the latter. The impact properties of the 3 pct Mn steel were worse than these two steels. The high TS × CIAV value for the 5 pct Mn steel at 293 K (25 °C) was mainly caused by the TRIP effect of a larger amount of retained austenite (36 vol pct) and the hardened matrix structure; low retained austenite stability and/or a hard martensite-austenite phase reduced this value. The higher ductile-brittle transition temperature of the 5 pct Mn steel was associated with Mn segregation, a large amount of unstable retained austenite on prior austenitic grain boundaries, and decreased cleavage fracture stress owing to the high Mn content.

  6. Photodegradation of sensitizers in mouse skin during PCT

    NASA Astrophysics Data System (ADS)

    Moan, Johan; Iani, Vladimir; Ma, Li Wei; Peng, Qian

    1996-01-01

    All photosensitizers applied in experimental and clinical photochemotherapy (PCT) of cancer are degraded during light exposure. Under certain conditions this may be a disadvantage since larger light fluences are needed to destroy the malignant tissue. However, photodegradation may also offer an advantage: if the applied dose of sensitizer is so low that most of it is photodegraded before normal tissue is destroyed, but still large enough to sensitize the tumor to destruction, one may achieve a larger tumor to normal tissue therapeutic ratio than when using a higher dose of sensitizer. Tumors usually contain two to ten times higher concentrations of sensitizers than do the surrounding normal tissues. We have studied the photodegradation of a number of sensitizers, including Photofrin (PII), benzoporphyrin derivative mono acid ring A (BPD), chlorin e6 (Chle6) 5-aminolevulinic acid (ALA)- induced protoporphyrin IX (PpIX), meso-tetrahydroxyphenyl-chlorin (m-THPC), meso- tetrahydroxyphenyl-porphyrin (m-THPP) tetraphenylporphine tetrasulfonated (TPPS4), aluminum phthalocyanine disulfonated (AlPcS2), tetrasulfonated (AlPcS4) and zinc phthalocyanine (ZnPc) in liposomes. The sensitizers were injected in Balb/c nude mice and exposed to light from an argon pumped dye laser, tuned to the appropriate therapeutic wavelength at a fluence rate of 100 mW/cm2. The sensitizer fluorescence in the laser- exposed skin was monitored by a fiberoptic probe coupled to a fluorescence spectrometer. The kinetics of the fluorescence decay during PCT were, in all cases, nonexponential but differed from dye to dye. Chle6 and m-THPC were found to be the most photolabile sensitizers. AlPcS4 and AlPcS2 and, to a minor degree, TPPS4 showed a peculiar fluorescence increase during PCT, similar to what we have found earlier for these sensitizers in cells in vitro. The fluorescence increase is indicative of lysosomal localization and perforation of the lysosomes during PCT.

  7. GEANT4 Tuning For pCT Development

    NASA Astrophysics Data System (ADS)

    Yevseyeva, Olga; de Assis, Joaquim T.; Evseev, Ivan; Schelin, Hugo R.; Paschuk, Sergei A.; Milhoretto, Edney; Setti, João A. P.; Díaz, Katherin S.; Hormaza, Joel M.; Lopes, Ricardo T.

    2011-08-01

    Proton beams in medical applications deal with relatively thick targets like the human head or trunk. Thus, the fidelity of proton computed tomography (pCT) simulations as a tool for proton therapy planning depends in the general case on the accuracy of results obtained for the proton interaction with thick absorbers. GEANT4 simulations of proton energy spectra after passing thick absorbers do not agree well with existing experimental data, as showed previously. Moreover, the spectra simulated for the Bethe-Bloch domain showed an unexpected sensitivity to the choice of low-energy electromagnetic models during the code execution. These observations were done with the GEANT4 version 8.2 during our simulations for pCT. This work describes in more details the simulations of the proton passage through aluminum absorbers with varied thickness. The simulations were done by modifying only the geometry in the Hadrontherapy Example, and for all available choices of the Electromagnetic Physics Models. As the most probable reasons for these effects is some specific feature in the code, or some specific implicit parameters in the GEANT4 manual, we continued our study with version 9.2 of the code. Some improvements in comparison with our previous results were obtained. The simulations were performed considering further applications for pCT development.

  8. Hot Ductility Behavior of an 8 Pct Cr Roller Steel

    NASA Astrophysics Data System (ADS)

    Wang, Zhenhua; Sun, Shuhua; Shi, Zhongping; Wang, Bo; Fu, Wantang

    2015-04-01

    The hot ductility of an 8 pct Cr roller steel was determined between 1173 K and 1473 K (900 °C and 1200 °C) at strain rates of 0.01 to 10 s-1 through tensile testing. The fracture morphology was observed using scanning electron microscopy, and the microstructure was examined through optical microscopy and transmission electron microscopy. The dependence of the hot ductility behavior on the deformation conditions, grain size, and precipitation was analyzed. The relationship between the reduction in area and the natural logarithm of the Zener-Hollomon parameter (ln Z) was found to be a second-order polynomial. When ln Z was greater than 40 s-1, the hot ductility was poor and fracture was mainly caused by incompatible deformation between the grains. When ln Z was between 32 and 40 s-1, the hot ductility was excellent and the main fracture mechanism was void linking. When ln Z was below 32 s-1, the hot ductility was poor and fracture was mainly caused by grain boundary sliding. A fine grain structure is beneficial for homogenous deformation and dynamic recrystallization, which induces better hot ductility. The effect of M7C3 carbide particles dispersed in the matrix on the hot ductility was small. The grain growth kinetics in the 8 pct Cr steel were obtained between 1373 K and 1473 K (1100 °C and 1200 °C). Finally, optimized preheating and forging procedures for 8 pct Cr steel rollers are provided.

  9. Application of PCT to the EBR II ceramic waste form.

    SciTech Connect

    Ebert, W. L.; Lewis, M. A.; Johnson, S. G.

    2002-01-10

    We are evaluating the use of the Product Consistency Test (PCT) developed to monitor the consistency of borosilicate glass waste forms for application to the multiphase ceramic waste form (CWF) that will be used to immobilize waste salts generated during the electrometallurgical conditioning of spent sodium-bonded nuclear fuel from the Experimental Breeder Reactor No. 2 (EBR II). The CWF is a multiphase waste form comprised of about 70% sodalite, 25% borosilicate glass binder, and small amounts of halite and oxide inclusions. It must be qualified for disposal as a non-standard high-level waste (HLW) form. One of the requirements in the DOE Waste Acceptance System Requirements Document (WASRD) for HLW waste forms is that the consistency of the waste forms be monitored.[1] Use of the PCT is being considered for the CWF because of the similarities of the dissolution behaviors of both the sodalite and glass binder phases in the CWF to borosilicate HLW glasses. This paper provides (1) a summary of the approach taken in selecting a consistency test for CWF production and (2) results of tests conducted to measure the precision and sensitivity of the PCT conducted with simulated CWF.

  10. Effect of Wavelike Sloping Plate Rheocasting on Microstructures of Hypereutectic Al-18 pct Si-5 pct Fe Alloys

    NASA Astrophysics Data System (ADS)

    Guan, Ren-Guo; Zhao, Zhan-Yong; Lee, Chong Soo; Zhang, Qiu-Sheng; Liu, Chun-Ming

    2012-04-01

    To refine and spheroidize the microstructures of hypereutectic Al-Si-Fe alloys, a novel method of wavelike sloping plate (WSP) rheocasting was proposed, and the effect of the WSP rheocasting on the microstructures of hypereutectic Al-18 pct Si-5 pct Fe alloys was investigated. The results reveal that the morphologies of the primary Si crystal, the Al18Si10Fe5, and the Al8Si2Fe phases can be improved by the WSP rheocasting, and various phases tend to be refined and spheroidized with the decrease of the casting temperature. The alloy ingots with excellent microstructures can be obtained when the casting temperature is between 943 K and 953 K (670 °C and 680 °C). During the WSP rheocasting, the crystal nucleus multiplication, inhibited grain growth, and dendrite break-up take place simultaneously, which leads to grain refinement of the alloys.

  11. Effect composition of SiCp and TiB to the mechanical properties of composite Al7Si-Mg-SiCp by the method of semi solid stir casting

    NASA Astrophysics Data System (ADS)

    Bhiftime, E. I.; Sulardjaka, Nugroho, Sri

    2016-04-01

    Recently, studies on Aluminum Matrix Composite (AMC) were growing rapidly. AMC reinforced with SiCp particles in the semi solid stir casting method was the most simple way. In particular, the purpose of the present study was to investigate the effect composition of SiCp and TiB to the mechanical properties of the composites Al7Si-Mg-SiCp and Al7Si-Mg-TiB-SiCp. The composites used were Al7Si as the matrix and SiCp as the reinforcement (10, 15, 20 wt%). The casting method used on the study was the semi solid stir casting. The matrix was melted at the temperature of 800 °C. Then, the stirring process started at 590 °C with the speed of 500 rpm for 180 seconds. The composites was heated again until the pouring temperature was at 750 °C. The results of the present study indicated to be successful in which SiCp particles dispersed uniformly in the matrix composites. Further, the hardness value and porosity of the composites Al7Si-Mg-SiCp and Al7Si-Mg-TiB-SiCp increased along with the addition of TiB. Besides, the hardness value increased in the average of 10.5% at the variation of 20% SiCp. Whereas, the porosity value increased in the average of 54.3% at the variation of 20% SiCp.

  12. Directionally Solidified Aluminum - 7 wt% Silicon Alloys: Comparison of Earth and International Space Station Processed Samples

    NASA Technical Reports Server (NTRS)

    Grugel, Richard N,; Tewari, Surendra; Rajamure, R. S.; Erdman, Robert; Poirier, David

    2012-01-01

    Primary dendrite arm spacings of Al-7 wt% Si alloy directionally solidified in low gravity environment of space (MICAST-6 and MICAST-7: Thermal gradient approx. 19 to 26 K/cm, Growth speeds varying from 5 to 50 microns/s show good agreement with the Hunt-Lu model. Primary dendrite trunk diameters of the ISS processed samples show a good fit with a simple analytical model based on Kirkwood s approach, proposed here. Natural convection, a) decreases primary dendrite arm spacing. b) appears to increase primary dendrite trunk diameter.

  13. CHEMICAL COMPOSITION AND PCT DATA FOR THE INITIAL SET OF HANFORD ENHANCED WASTE LOADING GLASSES

    SciTech Connect

    Fox, K.; Edwards, T.

    2014-06-02

    oxides that ranged from about 98 to 101.5 wt % for the study glasses, indicating excellent recovery of all the components in the chemical composition analyses. Comparisons of the targeted and measured chemical compositions indicated that, in general, the measured values for the glasses met the targeted concentrations. Exceptions were Cr{sub 2}O{sub 3}, MgO, and P{sub 2}O{sub 5}. The measured values for Cr{sub 2}O{sub 3} were somewhat low when compared to the targeted values for all of the study glasses targeting Cr{sub 2}O{sub 3} concentrations above 0.5 wt %. Many of the measured MgO and P{sub 2}O{sub 5} values were below the targeted values for those glasses that contained these components. Two of the study glasses exhibited differences from the targeted compositions that may indicate a batching error. Glasses EWG-HAI-Centroid-2 and EWG-OL-1672 had measured values for Al{sub 2}O{sub 3} and SiO{sub 2} that were lower than the targeted values, and measured values for B{sub 2}O{sub 3} that were higher than the targeted values. Glass EWG-HAI-Centroid-2 also had a measured value for Fe{sub 2}O{sub 3} that was lower than the targeted value. A review of the PCT data, including standards and blanks, revealed no issues with the performance of the tests. The PCT results were normalized to both the targeted and measured compositions of the study glasses. Comparisons of the normalized PCT results for both the quenched and Canister Centerline Cooled versions of the study glasses are made with the Environmental Assessment benchmark glass for reference.

  14. Dislocations in extruded Co-49.3 at. pct Al

    NASA Technical Reports Server (NTRS)

    Yaney, D. L.; Nix, W. D.; Pelton, A. R.

    1986-01-01

    Polycrystalline Co-49.3 at. pct Al, which had been extruded at 1505 K, was examined using transmission electron microscopy. Diffraction contrast analysis showed that b = 100 as well as b = 111 line dislocations contribute to elevated temperature deformation in CoAl. Therefore, it was concluded that sufficient slip systems exist in CoAl to allow for general plasticity in the absence of diffusional mechanisms. Line dislocations of the type b = 001 were observed on both 110 and 100 planes while b = 111 line dislocations were observed on 1 -1 0 planes.

  15. Mechanical properties and corrosion resistance of Ti-6Al-7Nb alloy dental castings.

    PubMed

    Kobayashi, E; Wang, T J; Doi, H; Yoneyama, T; Hamanaka, H

    1998-10-01

    With the aim of applying a novel titanium alloy, Ti-6Al-7Nb, to a dental casting material, a comprehensive research work was carried out on its characteristics, such as castability, mechanical properties and corrosion resistance in the present study. As a result, Ti-6Al-7Nb alloy exhibited sufficient castability by a dental casting method for titanium alloys and enough mechanical properties for dental application. It is also showed excellent corrosion resistance through an immersion test in 1.0% lactic acid and an anodic polarization test in 0.9% NaCl solution. From these results, it is concluded that this Ti-6Al-7Nb alloy is applicable as a dental material in place of Ti-6Al-4V alloy, which includes cytotoxic vanadium. PMID:15348689

  16. PCT-233, a novel modulator of pro- and anti-inflammatory cytokine production

    PubMed Central

    BISSONNETTE, E Y; PROULX, L-I; TURMEL, V; DROUIN, R; PURCELL, M

    2004-01-01

    Plant extracts have been implicated in various immunoregulatory effects that are poorly understood. Thus, we investigated the modulatory activity of PureCell Complex (PCT)-233, an active molecular complex from mesophyll tissue of Spinacia oleacea on the inflammatory process. Alveolar macrophages (AM) were treated with PCT-233 and/or budesonide, a well-known anti-inflammatory agent, before or after being stimulated with lipopolysaccharides (LPS). Pro- and anti-inflammatory cytokine production, tumour necrosis factor (TNF) and interleukin (IL)-10, respectively, were measured in cell-free supernatants at different times after the treatment. PCT-233 increased unstimulated AM release of both TNF and IL-10, whereas heat- and light-inactivated PCT-233 stimulated only the release of TNF without affecting IL-10 production, suggesting that different mechanisms are involved in the modulation of TNF and IL-10 release by PCT-233. The presence of LPS did not modify PCT-233-stimulated TNF production, but the ratio TNF/IL-10 production by LPS-stimulated AM was reduced significantly in the presence of PCT-233. Pretreatment of AM with PCT-233 and budesonide before LPS stimulation reduced TNF production at both protein and mRNA levels, whereas IL-10 production was increased. Moreover, TNF/IL-10 ratio was reduced further with the combination PCT-233/budesonide. Interestingly, AM treatment with PCT-233 and budesonide 18 h after LPS stimulation did not modulate TNF release significantly but it did increase IL-10 production, and a synergistic effect was observed with the combination PCT-233/budesonide. These exciting data suggest that PCT-233 possesses some anti-inflammatory properties, even when added during the inflammatory process, and could potentiate the effect of other anti-inflammatory agents. PMID:15008976

  17. WT1 mutations in T-ALL.

    PubMed

    Tosello, Valeria; Mansour, Marc R; Barnes, Kelly; Paganin, Maddalena; Sulis, Maria Luisa; Jenkinson, Sarah; Allen, Christopher G; Gale, Rosemary E; Linch, David C; Palomero, Teresa; Real, Pedro; Murty, Vundavalli; Yao, Xiaopan; Richards, Susan M; Goldstone, Anthony; Rowe, Jacob; Basso, Giuseppe; Wiernik, Peter H; Paietta, Elisabeth; Pieters, Rob; Horstmann, Martin; Meijerink, Jules P P; Ferrando, Adolfo A

    2009-07-30

    The molecular mechanisms involved in disease progression and relapse in T-cell acute lymphoblastic leukemia (T-ALL) are poorly understood. We used single nucleotide polymorphism array analysis to analyze paired diagnostic and relapsed T-ALL samples to identify recurrent genetic alterations in T-ALL. This analysis showed that diagnosis and relapsed cases have common genetic alterations, but also that relapsed samples frequently lose chromosomal markers present at diagnosis, suggesting that relapsed T-ALL emerges from an ancestral clone different from the major leukemic population at diagnosis. In addition, we identified deletions and associated mutations in the WT1 tumor suppressor gene in 2 of 9 samples. Subsequent analysis showed WT1 mutations in 28 of 211 (13.2%) of pediatric and 10 of 85 (11.7%) of adult T-ALL cases. WT1 mutations present in T-ALL are predominantly heterozygous frameshift mutations resulting in truncation of the C-terminal zinc finger domains of this transcription factor. WT1 mutations are most prominently found in T-ALL cases with aberrant rearrangements of the oncogenic TLX1, TLX3, and HOXA transcription factor oncogenes. Survival analysis demonstrated that WT1 mutations do not confer adverse prognosis in pediatric and adult T-ALL. Overall, these results identify the presence of WT1 mutations as a recurrent genetic alteration in T-ALL. PMID:19494353

  18. Tensile strength and elongation of laser-welded Ti and Ti-6AL-7NB.

    PubMed

    Watanabe, Ikuya; Topham, D Scott

    2004-10-15

    This study established data demonstrating the possible laser-welded strengths of cast Ti and Ti-6Al-7Nb and compared them to those of two dental-casting alloys. Cast plates of Ti, Ti-6Al-7Nb, gold, and Co-Cr alloy were prepared. After polishing the surfaces to be welded, two plates were abutted and welded using an Nd:YAG laser at a pulse duration of 10 ms, spot diameter of 1 mm, and voltage of 200 V. Five specimens were prepared for each metal by welding either three or five spots unilaterally or bilaterally. The fracture load and percent elongation were measured at a crosshead speed of 1.0 mm/min. The bilaterally welded specimens performed significantly greater than unilaterally welded specimens in both fracture load and elongation whether they were welded with three or five spots per side. The bilaterally welded Ti and Ti-6Al-7Nb specimens were nearly as strong as their corresponding control specimens, whereas the gold and Co-Cr specimens were approximately half as strong. When a large proportion of the cross-sectional area of the joint is laser welded, the strength of the laser-welded portion of the cast Ti and Ti-6Al-7Nb may approach or equal that of the nonwelded metal frameworks. PMID:15368227

  19. [Joint prostheses components of warm-forged and surface treated Ti-6Al-7Nb alloy].

    PubMed

    Semlitsch, M; Weber, H; Streicher, R M; Schön, R

    1991-05-01

    In 1978 development of a TiAl alloy with the inert alloying element niobium was initiated. In 1984, the optimal composition was found to be Ti-6Al-7Nb (Protasul-100). This custom-made alloy for implants has the same alpha/beta micro-structure and equally good mechanical properties as Ti-6Al-4V. The corrosion resistance of Ti-6Al-7Nb is better than that of pure titanium and Ti-6Al-4V, due to the very dense and stable passive layer. Since 1985, highly stressed anchoring stems of various hip prosthesis designs have been manufactured from hot-forged Ti-6Al-7Nb/Protasul-100. Polished surfaces of hip, knee or wrist joints made of Ti-6Al-7Nb intended to articulate with polyethylene are surface-treated by the application of a very hard, 3-5 microns thick titanium nitride coating (Tribosul-TiN), or by oxygen diffusion hardening (Tribosul-ODH) to a depth of 30 microns. PMID:1859861

  20. Creep-Fatigue Interactions in a 9 Pct Cr-1 Pct Mo Martensitic Steel: Part I. Mechanical Test Results

    NASA Astrophysics Data System (ADS)

    Fournier, B.; Sauzay, M.; Caës, C.; Noblecourt, M.; Mottot, M.; Allais, L.; Tournie, I.; Pineau, A.

    2009-02-01

    Creep-fatigue (CF) tests are carried out on a modified 9 pct Cr-1 pct Mo (P91) steel at 550 °C. These CF tests are strain controlled during the cyclic part of the stress-strain hysteresis loop and then load controlled when the stress is maintained at its maximum value, to produce a prescribed value of the creep strain before cyclic deformation is reversed under strain-controlled conditions. The observed cyclic softening implies that the applied creep stress continuously decreases with the number of cycles. However, the minimum creep rates measured at the end of the holding periods do not decrease when the applied stress decreases. The minimum creep rates measured at the end of these tests can be hundreds of times faster than those observed for the as-received material. This acceleration of creep rates can be to the microstructural coarsening and to the decrease of the dislocation density observed after fatigue and CF loadings. Cyclic creep tests consisting of very long holding periods interrupted by unloading/reloading are also carried out. These results suggest that cyclic loadings affect the creep lifetime and flow behavior only if a plastic strain is applied during cycling. Creep tests carried out on a material cyclically prestrained and fatigue tests carried out on a material previously deformed in creep confirm that the deterioration of the mechanical properties is much faster in fatigue and CF compared to creep.

  1. Microstructure and mechanical behaviour of Ti-6Al-7Nb alloy produced by selective laser melting

    SciTech Connect

    Chlebus, Edward; Kuznicka, Bogumila Kurzynowski, Tomasz; Dybala, Bogdan

    2011-05-15

    Selective laser melting (SLM) is an advanced manufacturing technology providing alternative method of producing complex components directly from 3D computer models. The purpose of this work is to determine the influence of the SLM manufacturing strategy on mechanical properties and microstructure of the as-built Ti-Al-Nb alloy. Specimens of Ti-6Al-7Nb were produced in three versions of the specimen axis orientation with respect to its build direction. Mechanical characteristics of the alloy were determined by tensile and compression testing, as well as hardness measurements. Microstructures were characterised utilising optical microscopy, scanning electron microscopy and X-ray diffraction analysis. It was found that the as-built Ti-6Al-7Nb alloy has microstructure of {alpha}' martensite hardened by dispersive precipitates of the second phase, which results in higher tensile and compressive strengths, but lower ductility in comparison to those of an alloy manufactured by conventional methods. The layered microstructure of the material gives it a significant anisotropy of Young's modulus, moderate anisotropy of mechanical properties, but strong anisotropy of sensitivity to the build porosity. The paper develops understanding of the relationships between the strategy of layered manufacturing of the Ti-6Al-7Nb alloy and its microstructural and mechanical characteristics. This is important for future applications of the SLM technology for producing Ti-6Al-7Nb parts, e.g. the custom medical implants. - Research Highlights: {yields} The as-built SLM Ti-6Al-7Nb alloy has a layered microstructure of {alpha}' martensite. {yields} Size and orientation of the {alpha}' plates are determined by the SLM building strategy. {yields} The layered microstructure gives the alloy an anisotropy of Young's modulus. {yields} The building strategy influences anisotropy of material sensitivity to the built porosity.

  2. Analysis of the Tensile Behavior of 12 pct Mn Multi-phase ( α + γ) TWIP + TRIP Steel by Neutron Diffraction

    NASA Astrophysics Data System (ADS)

    Lee, Sangwon; Woo, Wanchuck; de Cooman, Bruno C.

    2016-05-01

    The tensile behavior of intercritically annealed Fe-12 pctMn-0.3 pctC-2 pctAl and Fe-12 pctMn-0.3 pctC-3 pctAl steel was studied by means of in situ neutron diffraction and microstructural analysis. The in situ neutron diffraction measurements showed that the ferrite had a much higher yield strength and lower work hardening rate as compared to the austenite. The strain hardening of the austenite was controlled by deformation twinning and strain-induced transformation, occurring in succession. This TWIP + TRIP effect acted as an effective plasticity-enhancing mechanism which increased the work hardening rate.

  3. Portable Computer Technology (PCT) Research and Development Program Phase 2

    NASA Technical Reports Server (NTRS)

    Castillo, Michael; McGuire, Kenyon; Sorgi, Alan

    1995-01-01

    The subject of this project report, focused on: (1) Design and development of two Advanced Portable Workstation 2 (APW 2) units. These units incorporate advanced technology features such as a low power Pentium processor, a high resolution color display, National Television Standards Committee (NTSC) video handling capabilities, a Personal Computer Memory Card International Association (PCMCIA) interface, and Small Computer System Interface (SCSI) and ethernet interfaces. (2) Use these units to integrate and demonstrate advanced wireless network and portable video capabilities. (3) Qualification of the APW 2 systems for use in specific experiments aboard the Mir Space Station. A major objective of the PCT Phase 2 program was to help guide future choices in computing platforms and techniques for meeting National Aeronautics and Space Administration (NASA) mission objectives. The focus being on the development of optimal configurations of computing hardware, software applications, and network technologies for use on NASA missions.

  4. Multi-layer laser solid forming of Zr65Al7.5Ni10Cu17.5 amorphous coating: Microstructure and corrosion resistance

    NASA Astrophysics Data System (ADS)

    Gan, Yu; Wang, Wenxian; Guan, Zhuosen; Cui, Zeqin

    2015-06-01

    Multi-layer Zr65Al7.5Ni10Cu17.5 amorphous coatings were produced by laser solid forming on A283 substrate. The coatings with few pores and free of cracks had good metallurgical bonding with the substrate. The microstructural characterization, phase composition, chemical component distribution and corrosion behavior of the coatings were investigated. The results revealed that the amorphization degree increased from the substrate to the coating surface mainly due to the dilution and stir influence from the melted substrate. In the five layers coating, the volume fraction of amorphous phase in the 5th layer, 3rd layer and 1st layer was about 77%, 64% and 49% respectively. With regard to corrosion property, potentiodynamic polarization plots, Nyquist plots and the equivalent circuits were employed in 3.5 wt% sodium chloride solution. Attributing to the presence of amorphous phase and passivation, the LSF coatings exhibit excellent corrosion resistance.

  5. Association of WT1 IgG antibody against WT1 peptide with prolonged survival in glioblastoma multiforme patients vaccinated with WT1 peptide.

    PubMed

    Oji, Yusuke; Hashimoto, Naoya; Tsuboi, Akihiro; Murakami, Yui; Iwai, Miki; Kagawa, Naoki; Chiba, Yasuyoshi; Izumoto, Shuichi; Elisseeva, Olga; Ichinohasama, Ryo; Sakamoto, Junichi; Morita, Satoshi; Nakajima, Hiroko; Takashima, Satoshi; Nakae, Yoshiki; Nakata, Jun; Kawakami, Manabu; Nishida, Sumiyuki; Hosen, Naoki; Fujiki, Fumihiro; Morimoto, Soyoko; Adachi, Mayuko; Iwamoto, Masahiro; Oka, Yoshihiro; Yoshimine, Toshiki; Sugiyama, Haruo

    2016-09-15

    We previously evaluated Wilms' tumor gene 1 (WT1) peptide vaccination in a large number of patients with leukemia or solid tumors and have reported that HLA-A*24:02 restricted, 9-mer WT1-235 peptide (CYTWNQMNL) vaccine induces cellular immune responses and elicits WT1-235-specific cytotoxic T lymphocytes (CTLs). However, whether this vaccine induces humoral immune responses to produce WT1 antibody remains unknown. Thus, we measured IgG antibody levels against the WT1-235 peptide (WT1-235 IgG antibody) in patients with glioblastoma multiforme (GBM) receiving the WT1 peptide vaccine. The WT1-235 IgG antibody, which was undetectable before vaccination, became detectable in 30 (50.8%) of a total of 59 patients during 3 months of WT1 peptide vaccination. The dominant WT1-235 IgG antibody subclass was Th1-type, IgG1 and IgG3 . WT1-235 IgG antibody production was significantly and positively correlated with both progression-free survival (PFS) and overall survival (OS). Importantly, the combination of WT1-235 IgG antibody production and positive delayed type-hypersensitivity (DTH) to the WT1-235 peptide was a better prognostic marker for long-term OS than either parameter alone. These results suggested that WT1-235 peptide vaccination induces not only WT1-235-specific CTLs as previously described but also WT1-235-specific humoral immune responses associated with antitumor cellular immune response. Our results indicate that the WT1 IgG antibody against the WT1 peptide may be a useful predictive marker, with better predictive performance in combination with DTH to WT1 peptide, and provide a new insight into the antitumor immune response induction in WT1 peptide vaccine-treated patients. PMID:27170523

  6. [Use of procalcitonine in intensive care units: comparison of semi quantitative PCT-Q Brahms assay with automated PCT-Kryptor assay].

    PubMed

    Schuch, Géraldine; Duc-Marchand, Catherine; Venet, Cyrille; Mann, Hubert; Tixier, Anne; Bionda, Clara

    2011-01-01

    Procalcitonine (PCT) is recognized as a major and specific biomarker in diagnosis of bacterial infection. Used early in sepsis, it allows immediate administration of antibiotics and monitoring its effectiveness. Confronted on systemic inflammation response syndrom (SIRS), physicians must react quickly and effectively to evaluate bacterial infection and sepsis. The objective of this study was to compare analytical and clinical performances of semi-quantitative PCT-Q assay (Brahms) with quantitative and automated assay such on Kryptor (Brahms). Fifty blood samples of intensive care patients were compared. The analytical performance observed with PCT-Q assay is accurate: linear ratio kappa of 0.912 (95% CI 0.61, 0.97) and a good correlation between these techniques (p < 0.0001) (MedCalc software) were observed. Three discordances were observed and confirm the difficulties of reading for values close to 0.5 ng/mL. For these patients, PCT result showed its interest to discriminate local infection of a sepsis, to stop antibiotherapy with broad spectrum and to consolidate a therapeutic effectiveness in multi-visceral failure context. The semi-quantitative assay seems adapted for a fast and reliable evaluation of PCT in a general-purpose laboratory, not requiring neither dedicated analyzer, nor complex technicality but a control of the visual evaluation of results. It could be used for diagnosis of sepsis without monitoring precisely therapeutic follow-up. PMID:22123565

  7. Enhancement of Upper Shelf Energy through Delamination Fracture in 0.05 pct P Doped High-Strength Steel

    NASA Astrophysics Data System (ADS)

    Jafari, Meysam; Kimura, Yuuji; Tsuzaki, Kaneaki

    2012-07-01

    An ultrafine elongated grain (UFEG) structure with strong <110>//rolling direction (RD) fiber deformation texture was produced by warm-caliber rolling at 773 K (500 °C) and final tempering at 823 K (550 °C), namely tempforming in the 1200 MPa-class, medium-carbon, low-alloy steel with phosphorus (P) content of 0.053 wt pct. Charpy impact tests and tensile tests were performed at a temperature range of 77 K (-196 °C) to 623 K (350 °C) on the tempformed (TF) samples along with a conventional quenched and tempered (QT) samples. The QT structure showed a low upper shelf energy of 70 J and a high ductile-to-brittle transition temperature (DBTT) of 373 K (100 °C) as a result of P segregation and intergranular fracture. A remarkable increase in the upper shelf energy to 150 J from 70 J and a low DBTT of approximately 103 K (-170 °C) were obtained in the UFEG structure. P segregation embrittlement disappeared completely in the UFEG structure, and ductile fracture on the planes normal to RD along with delamination fracture on the planes along RD were observed at a temperature range of 123 K (-150 °C) to 423 K (150 °C). The enhanced delamination occurred because of the microstructural anisotropy of the UFEG structure, a strong <110>//RD fiber deformation texture, and interfaces ( i.e. ferrite grain boundaries and cementite particles-ferrite matrix interfaces) weakened by P segregation as feasible crack propagation paths. We studied the delamination (crack-arrester-type) fracture in 0.053 pct P doped high-strength steel along with upper shelf energy and DBTT obtained from the UFEG structure.

  8. Letter report on PCT/Monolith glass ceramic corrosion tests

    SciTech Connect

    Crawford, Charles L.

    2015-09-24

    The Savannah River National Laboratory (SRNL) is collaborating with personnel from Pacific Northwest National Laboratory (PNNL) to study advanced waste form glass ceramics for immobilization of waste from Used Nuclear Fuel (UNF) separations processes. The glass ceramic waste forms take advantage of both crystalline and glassy phases where ‘troublesome’ elements (e.g., low solubility in glass or very long-lived) partition to highly durable ceramic phases with the remainder of elements residing in the glassy phase. The ceramic phases are tailored to create certain minerals or unique crystalline structures that can host the radionuclides by binding them in their specific crystalline network while not adversely impacting the residual glass network (Crum et al., 2011). Glass ceramics have been demonstrated using a scaled melter test performed in a pilot scale (1/4 scale) cold crucible induction melter (CCIM) (Crum et al., 2014; Maio et al., 2015). This report summarizes recent results from both Phase I and Phase II bench scale tests involving crucible fabrication and corrosion testing of glass ceramics using the Product Consistency Test (PCT). Preliminary results from both Phase I and Phase II bench scale tests involving statistically designed matrices have previously been reported (Crawford, 2013; Crawford, 2014).

  9. Time-resolved FRET and PCT in cationic conjugated polymer/dye-labeled DNA complex

    NASA Astrophysics Data System (ADS)

    Kim, Inhong; Kim, Jihoon; Kim, Bumjin; Kang, Mijeong; Woo, Han Young; Kyhm, Kwangseuk

    2011-12-01

    The energy transfer mechanism between cationic conjugated polyelectrolytes and a single stranded DNA labeled with fluorescein was investigated in terms of Förster resonance energy transfer (FRET) and photo-induced charge transfer (PCT) by time-resolved fluorescence. Both FRET and PCT rate efficiencies were obtained by phenomenological coupled rate equations, which are in excellent agreement with experiments. We found the total energy transfer in the complex is maximized as a consequence of FRET and PCT at an optimum distance 32.7Å.

  10. On the assertion that PCT violation implies Lorentz non-invariance

    NASA Astrophysics Data System (ADS)

    Dütsch, Michael; Gracia-Bondía, José M.

    2012-05-01

    Out of conviction or expediency, some current research programs (Kostelecký (2008) [1], Kostelecký and Russell (2011) [2], Ferrero and Altschul (2011) [3], Anselmi (2009) [4]) take for granted that "PCT violation implies violation of Lorentz invariance". We point out that this claim (Greenberg (2002) [5]) is still on somewhat shaky ground. In fact, for many years there has been no strengthening of the evidence in this direction. However, using causal perturbation theory, we prove here that when starting with a local PCT-invariant interaction, PCT symmetry can be maintained in the process of renormalization.

  11. Photolysis of rhodamine-WT dye

    USGS Publications Warehouse

    Tai, D.Y.; Rathbun, R.E.

    1988-01-01

    Photolysis of rhodamine-WT dye under natural sunlight conditions was determined by measuring the loss of fluorescence as a function of time. Rate coefficients at 30?? north latitude ranged from 4.77 x 10-2 day-1 for summer to 3.16 x 10-2 day-1 for winter. Experimental coefficients were in good agreement with values calculated using a laboratory-determined value of the quantum yield.

  12. Creep-Fatigue Interactions in a 9 Pct Cr-1 Pct Mo Martensitic Steel: Part II. Microstructural Evolutions

    NASA Astrophysics Data System (ADS)

    Fournier, B.; Sauzay, M.; Barcelo, F.; Rauch, E.; Renault, A.; Cozzika, T.; Dupuy, L.; Pineau, A.

    2009-02-01

    A multiscale characterization of the microstructural evolutions taking place in 9 to 12 pct Cr martensitic steels subjected to fatigue and creep-fatigue (CF) loadings is presented. Specimens of a P91 steel subjected to high-temperature cyclic loadings are examined using several experimental techniques. Bright-field transmission electron microscopy (TEM), electron backscattered diffraction (EBSD), and TEM orientation mapping are used to characterize and quantify the microstructural evolutions. A recovery phenomenon consisting of the coarsening of the subgrains and a decrease of the dislocation density is observed. This coarsening is heterogeneous and depends on the strain amplitude and on the applied hold time. The size distribution of subgrains and the dislocation density are measured from bright-field TEM observations. Orientation mapping on scanning electron microscopy (SEM) and TEM show that, even though a correlation between the crystallographic orientation and the recovery phenomenon is highlighted, a complex dependency related to the orientation of neighboring blocks exists. These microstructural observations are consistent with the very fast deterioration of creep properties due to cyclic loadings (reported in the first part of this study).

  13. Nuclear waste glass product consistency test (PCT), Version 5.0. Revision 2

    SciTech Connect

    Jantzen, C.M.; Bibler, N.E.; Beam, D.C.; Ramsey, W.G.; Waters, B.J.

    1992-06-01

    Liquid high-level nuclear waste will be immobilized at the Savannah River Site (SRS) by vitrification in borosilicate glass. The glass will be produced in the Defense Waste Processing Facility (DWPF), poured into stainless steel canisters, and eventually disposed of in a geologic repository. In order to comply with the Waste Acceptance Preliminary Specifications (WAPS), the durability of the glass needs to be measured during production to assure its long term stability and radionuclide release properties. A durability test, designated the Produce Consistency Test (PCT), was developed for DWPF glass in order to meet the WAPS requirements. The response of the PCT procedure was based on extensive testing with glasses of widely different compositions. The PCT was determined to be very reproducible, to yield reliable results rapidly, and to be easily performed in shielded cell facilities with radioactive samples. Version 5.0 of the PCT procedure is attached.

  14. Effects of physical activity on pupil cycle time (PCT) in healthy Indian male.

    PubMed

    Ghosh, Suparna; Avadhany, Sandhya T

    2014-01-01

    Globally, physical inactivity is an important risk factor for the development of non-communicable disease consisting of coronary artery disease, as well as, other diseases including hypertension, diabetes, obesity, osteoporosis, and certain types of cancers. Parasympathetic nervous system (PNS) activity in the eye is determined by the pupil cycle time (PCT) can be comparable with cardiac parasympathetic response and thereby determine the morbidity and mortality among individuals. The PCT is measured by throwing white light on the edge of the pupil. Pupil cycling is a feature of pupillary reflex arc. The aim of this study is to establish the effect of physical activity on the PCT. The counting of PCT was done for 90 cycles and average one count is considered a single PCT. The physical activity level (PAL) was determined by administering a physical activity level questionnaire developed in the Division of Nutrition, St. John's Medical College, Bangalore. The PAL is classified as < 1.4 as sedentary, 1.55 to 1.75 moderately active, and > 1.75 heavily active. Thirty healthy male volunteers in the age group of 18-50 years and with BMI of 18.5 kg/m2-30 kg/m2 were studied. We obtained PCT of 962.00 ± 105.72 msec in sedentary, 896.77 ± 85.88 msec in moderately active and 889.45 ± 68.71 msec in heavily active individuals. Linear regression analysis shows there is statistically significant difference between the three different groups of physical activity level with a b value of 0 and R2 being 0.19. Increase in physical activity led to decrease in the PCT i.e. increase in the parasympathetic tone in the eye. Pupil cycle time (PCT) is a simple noninvasive tool to assess and differentiate the PNS function in different activity level of individual. PMID:25906609

  15. Early Assessment of Pancreatic Infections and Overall Prognosis in Severe Acute Pancreatitis by Procalcitonin (PCT)

    PubMed Central

    Rau, Bettina M.; Kemppainen, Esko A.; Gumbs, Andrew A.; Büchler, Markus W.; Wegscheider, Karl; Bassi, Claudio; Puolakkainen, Pauli A.; Beger, Hans G.

    2007-01-01

    Background: Pancreatic infections and sepsis are major complications in severe acute pancreatitis (AP) with significant impact on management and outcome. We investigated the value of Procalcitonin (PCT) for identifying patients at risk to develop pancreatic infections in severe AP. Methods: A total of 104 patients with predicted severe AP were enrolled in five European academic surgical centers within 96 hours of symptom onset. PCT was measured prospectively by a semi-automated immunoassay in each center, C-reactive protein (CRP) was routinely assessed. Both parameters were monitored over a maximum of 21 consecutive days and in weekly intervals thereafter. Results: In contrast to CRP, PCT concentrations were significantly elevated in patients with pancreatic infections and associated multiorgan dysfunction syndrome (MODS) who all required surgery (n = 10) and in nonsurvivors (n = 8) early after onset of symptoms. PCT levels revealed only a moderate increase in patients with pancreatic infections in the absence of MODS (n = 7), all of whom were managed nonoperatively without mortality. A PCT value of ≥3.5 ng/mL on 2 consecutive days was superior to CRP ≥430 mg/L for the assessment of infected necrosis with MODS or nonsurvival as determined by ROC analysis with a sensitivity and specificity of 93% and 88% for PCT and 40% and 100% for CRP, respectively (P < 0.01). The single or combined prediction of the two major complications was already possible on the third and fourth day after onset of symptoms with a sensitivity and specificity of 79% and 93% for PCT ≥3.8 ng/mL compared with 36% and 97% for CRP ≥430 mg/L, respectively (P = 0.002). Conclusion: Monitoring of PCT allows early and reliable assessment of clinically relevant pancreatic infections and overall prognosis in AP. This single test parameter significantly contributes to an improved stratification of patients at risk to develop major complications. PMID:17457167

  16. Texture development in dual-phase cold-rolled 18 pct Ni maraging steel

    SciTech Connect

    Ahmad, Z.; Farooque, M.; Ul Haq, A.; Khan, A.Q.

    1997-12-01

    Austenite and martensite textures were studied in 18 pct Ni 350-maraging steel as a function of various degrees of cold rolling. The austenite phase in the samples was produced by repeated thermal cycling between ambient and 800 C. The austenite phase thus formed was mechanically unstable and transformed to the martensite phase after 30 pct cold rolling. The texture developed as a result of cold rolling, and its effect upon microstructure and hardness has been studied.

  17. Numerical Simulation of Three-Dimensional Dendritic Growth of Alloy: Part II—Model Application to Fe-0.82WtPctC Alloy

    NASA Astrophysics Data System (ADS)

    Wang, Weiling; Luo, Sen; Zhu, Miaoyong

    2016-03-01

    In the second part (Part II) of the present simulation work, the three-dimensional (3D) dendritic growth of Fe-0.82wtpctC alloy is investigated with the 3D CA-FVM cellular automaton-finite volume method model developed in Part I. The influences of the melt undercooling, the interfacial anisotropy, and the forced flow on the equiaxed dendritic growth, especially the formation of secondary arms, are discussed. The comparisons of equiaxed dendritic growth in 3D and two-dimensional (2D) are also carried out. Finally, the columnar dendritic growth under different cooling conditions is investigated including the morphology and the secondary dendrite arm spacing (SDAS). The results show that the high undercooling can promote the formation of secondary arms as the anisotropy parameter is 0.04. With the increase of the anisotropy parameter, the secondary arms first reduce and then well develop again; meanwhile the tertiary arms are gradually developed. However, the secondary arms vanish at the undercooling of 5 K as the anisotropy parameter increases to 0.04. With the introduction of the forced flow with the inlet velocity of 0.001 m/s along the x axis, the secondary arms at the left (upstream) arm become more developed. However, they become slightly less developed with the forced flow intensifying. Secondary arms at the left side (upstream) of the perpendicular arms and in the y-z symmetrical plane become more and more developed as the inlet velocity increases. The competition of the secondary arms at the right side (downstream) of the perpendicular arms and at the right (downstream) arm becomes significant as the undercooling increases from 10 to 15 K. The solute-enriched envelope in 2D is much thicker than in the 3D case, so that the dendritic growth in 2D is influenced more by the melt flow and the undercooling; moreover, the secondary arms in 2D are hard to form even at the undercooling of 15 K and with the forced convection in the present article. Meanwhile, the variation tendency of the movement of columnar dendritic tip and the decrement of the average SDAS with every 0.025-MW/m2 increment of the heat flux are quite different.

  18. Purification, crystallization and preliminary crystallographic analysis of the ligand-binding regions of the PctA and PctB chemoreceptors from Pseudomonas aeruginosa in complex with amino acids

    PubMed Central

    Rico-Jiménez, Miriam; Muñoz-Martínez, Francisco; Krell, Tino; Gavira, Jose A.; Pineda-Molina, Estela

    2013-01-01

    Pseudomonas aeruginosa is an opportunistic pathogen and one of the major model organisms for the study of chemotaxis. The bacterium harbours 26 genes encoding chemoreceptors, most of which have not been annotated with a function. The paralogous chemoreceptors PctA and PctB (Pseudomonas chemotactic transducer A and B) were found to mediate chemotaxis towards l-amino acids. However, the ligand spectrum of the receptors is quite different since the recombinant ligand-binding region (LBR) of PctA binds 17 different l-­amino acids whereas that of PctB recognizes only five. To determine the molecular basis underlying this ligand specificity, PctA-LBR and PctB-LBR have been purified and crystals have been produced after pre-incubation with l-­Ile and l-Arg, respectively. Initial crystallization conditions have been identified by the counter-diffusion method and X-ray data have been collected at 2.5 Å (PctA-LBR bound to l-Ile) and 3.14 Å (PctB-LBR bound to l-Arg) resolution. Crystals belonged to space groups P212121 and P3121, with unit-cell parameters a = 72.2, b = 78.5, c = 116.6 Å and a = b = 111.6, c = 117.4, respectively, for PctA-LBR and PctB-LBR. Molecular-replacement methods will be pursued for structural determination. PMID:24316847

  19. Enriching and Separating Primary Copper Impurity from Pb-3 Mass Pct Cu Melt by Super-Gravity Technology

    NASA Astrophysics Data System (ADS)

    Yang, Yuhou; Song, Bo; Song, Gaoyang; Yang, Zhanbing; Xin, Wenbin

    2016-08-01

    In this study, super-gravity technology was introduced in the lead bullion-refining process to investigate the enriching and separating laws of copper impurity from Pb-3 mass pct Cu melt. With the gravity coefficient G = 700 at the cooling rate of ν = 5 K min-1, the entire copper phase gathers at the upper area of the sample, and it is hard to find any copper particles at the bottom area of the sample. The floatation movement of copper phase was greatly intensified by super gravity and the mass pct of copper in tailing lead is up to 8.631 pct, while that in the refined lead is only 0.113 pct. The refining rate of lead bullion reached up to 94.27 pct. Copper-phase impurity can be separated effectively from Pb-3 mass pct Cu melt by filtration method in super-gravity field, and the separation efficiency increased with the increasing gravity coefficient in the range of G ≥ 10. After filtration at 613 K (340 °C) with gravity coefficient G = 100 for 10 minutes, the refined lead, with just 0.157 mass pct copper impurity, was separated to the bottom of the crucible, and the copper dross containing only 23.56 mass pct residual lead was intercepted by the carbon fiber felt, leading to the separation efficiency up to 96.18 pct (meaning a great reduction in metal loss).

  20. Hot deformation of U-9 wt% Mo

    NASA Astrophysics Data System (ADS)

    Kapoor, R.; Thota, M. K.; Chakravartty, J. K.; Basak, C. B.; Jha, S. K.; Hussain, M. M.

    2016-08-01

    Uranium - 9 wt% molybdenum in the as-extruded condition was deformed in compression in vacuum at temperatures from 850 to 1000 °C and strain rates from 3 × 10-3 to 1 s-1. The strain rate sensitivity (m) was computed and plotted as iso-strain rate sensitivity contour plots. m was around 0.33 at 950-1000 °C at strain rate of 3 × 10-3 s-1. Electron backscatter diffraction showed that at 1000 °C-3 × 10-3 s-1 grains refined, fraction of high angle boundaries increased and the average local misorientation reduced, all indicative of the occurrence of dynamic recrystallization. In comparison, at 950 and 900 °C both the fraction of low angle boundaries and local misorientation was higher. At 1000 °C-3 × 10-3 s-1 the [111] direction was aligned along the compression axis, whereas at lower temperature of 900 °C and 3 × 10-3 s-1 it was the orientations close to [001].

  1. Experimental investigation of thermal effects and PCT on FBGs-based linearly polarized fiber laser performance.

    PubMed

    Huang, Long; Ma, Pengfei; Tao, Rumao; Shi, Chen; Wang, Xiaolin; Zhou, Pu

    2015-04-20

    We experimentally study the impacts of thermal effects and polarization crosstalk (PCT) on the performance of FBGs-based linearly polarized all-fiber laser. The mechanism that the thermal effects and PCT influence the performance of the laser is analyzed. Thermally-dependent reflection peaks of polarization maintaining (PM) fiber Bragg gratings are revealed to be the prime reason why temperature influences spectrum, output power, and polarization property of the laser. The PCT would also influence the performance of the laser seriously in the case of mismatched angle even with effectively overlapped spectrum. It is revealed experimentally that stable linearly polarized output can be obtained if a certain pair of aligned principal axes of PM FBGs is not only spectrally overlapped but also strictly angle matched. Further, we point out that accurate temperature control and careful angle match are essential for stable linearly polarized output and even possible power scaling further. PMID:25969091

  2. A Study on the Oxidation Behavior of Nb Alloy (Nb-1 pct Zr-0.1 pct C) and Silicide-Coated Nb Alloys

    NASA Astrophysics Data System (ADS)

    Vishwanadh, B.; Naina, R. H.; Majumdar, S.; Tewari, R.; Dey, G. K.

    2013-05-01

    In the current work, silicide coatings were produced on the Nb alloy (Nb-1 pct Zr-0.1 pct C) using the halide activated pack cementation (HAPC) technique. Coating parameters (temperature and time) were optimized to produce a two-layer (Nb5Si3 and NbSi2) coating on the Nb alloy. Subsequently, the oxidation behavior of the Nb alloy (Nb-1 pct Zr-0.1 pct C) and silicide-coated Nb alloy was studied using thermogravimetric analysis (TGA) and isothermal weight gain oxidation experiments. Phase identification and morphological examinations were carried out using X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques. TGA showed that the Nb alloy started undergoing accelerated oxidation at and above 773 K (500 °C). Isothermal weight gain experiments carried out on the Nb alloy under air environment at 873 K (600 °C) up to a time period of 16 hours exhibited a linear growth rate law of oxidation. In the case of silicide-based coatings, TGA showed that oxidation resistance of silicide coatings was retained up to 1473 K (1200 °C). Isothermal weight gain experiments on the silicide coatings carried out at 1273 K (1000 °C) in air showed that initially up to 8 hours, the weight of the sample increased, and beyond 8 hours the weight of the sample remained constant. The oxide phases formed on the bare samples and on the coated samples during oxidation were found to be Nb2O5 and a mixture of SiO2 and Nb2O5 phases, respectively. SEM showed the formation of nonprotective oxide layer on the bare Nb alloy and a protective (adherent, nonporous) oxide layer on silicide-coated samples. The formation of protective SiO2 layer on the silicide-coated samples greatly improved the oxidation resistance at higher temperatures.

  3. Plasma arc melting of a 80 wt % tantalum-20 wt % titanium alloy

    SciTech Connect

    Dunn, P.S.; Patterson, R.A.

    1994-10-01

    An alloy of 80wt% tantalum-20wt% titanium is being considered for use in an oxidizing and highly corrosive liquid metal application. The high melting point of the alloy, 2400 C, and other physical properties narrowed the possible melting techniques. Previous melting experience with these materials by electron beam resulted in extensive vaporization of the titanium during the melt and poor chemical homogeneity. A technique has been developed using plasma arc melting to melt refractory alloys with very dissimilar densities and vapor pressures. The 80Ta--20Ti alloy falls into this category with the density of tantalum 16.5 g/cc and that of titanium 4.5 g/cc. The melting of these materials is further complicated by the high melting point of tantalum( 3020 C) and the relatively low boiling point of titanium( 3287 C). The plasma arc melting technique described results in good chemical homogeneity with ingot size quantities of material.

  4. A new equation for the Cr equivalent in 9 to 12 pct Cr steels

    SciTech Connect

    Ryu, S.H.; Yu, J.

    1998-06-01

    In advanced 9 to 12 pct Cr steels, the Cr equivalent is used as a measure to check the formation of {delta}-ferrite. In the present analysis, 29 alloys of varying composition were vacuum induction melted, and the amounts of {delta}-ferrite were measured in as-tempered conditions. Based on this and previous results on 9 to 12 pct Cr steels, a new equation for the Cr equivalent is proposed and correlated with the amount of {delta}-ferrite formation. Results indicate that the new Cr equivalent equation shows better correlation than previous equations and predicts the amount of {delta}-ferrite formed reasonably well.

  5. Identification of a Novel C-Terminal Truncated WT1 Isoform with Antagonistic Effects against Major WT1 Isoforms

    PubMed Central

    Tatsumi, Naoya; Hojo, Nozomi; Sakamoto, Hiroyuki; Inaba, Rena; Moriguchi, Nahoko; Matsuno, Keiko; Fukuda, Mari; Matsumura, Akihide; Hayashi, Seiji; Morimoto, Soyoko; Nakata, Jun; Fujiki, Fumihiro; Nishida, Sumiyuki; Nakajima, Hiroko; Tsuboi, Akihiro; Oka, Yoshihiro; Hosen, Naoki; Sugiyama, Haruo; Oji, Yusuke

    2015-01-01

    The Wilms’ tumor gene WT1 consists of 10 exons and encodes a zinc finger transcription factor. There are four major WT1 isoforms resulting from alternative splicing at two sites, exon 5 (17AA) and exon 9 (KTS). All major WT1 isoforms are overexpressed in leukemia and solid tumors and play oncogenic roles such as inhibition of apoptosis, and promotion of cell proliferation, migration and invasion. In the present study, a novel alternatively spliced WT1 isoform that had an extended exon 4 (designated as exon 4a) with an additional 153 bp (designated as 4a sequence) at the 3’ end was identified and designated as an Ex4a(+)WT1 isoform. The insertion of exon 4a resulted in the introduction of premature translational stop codons in the reading frame in exon 4a and production of C-terminal truncated WT1 proteins lacking zinc finger DNA-binding domain. Overexpression of the truncated Ex4a(+)WT1 isoform inhibited the major WT1-mediated transcriptional activation of anti-apoptotic Bcl-xL gene promoter and induced mitochondrial damage and apoptosis. Conversely, suppression of the Ex4a(+)WT1 isoform by Ex4a-specific siRNA attenuated apoptosis. These results indicated that the Ex4a(+)WT1 isoform exerted dominant negative effects on anti-apoptotic function of major WT1 isoforms. Ex4a(+)WT1 isoform was endogenously expressed as a minor isoform in myeloid leukemia and solid tumor cells and increased regardless of decrease in major WT1 isoforms during apoptosis, suggesting the dominant negative effects on anti-apoptotic function of major WT1 isoforms. These results indicated that Ex4a(+)WT1 isoform had an important physiological function that regulated oncogenic function of major WT1 isoforms. PMID:26090994

  6. Eutectic Morphology of Al-7Si-0.3Mg Alloys with Scandium Additions

    NASA Astrophysics Data System (ADS)

    Pandee, Phromphong; Gourlay, C. M.; Belyakov, S. A.; Ozaki, Ryota; Yasuda, Hideyuki; Limmaneevichitr, Chaowalit

    2014-09-01

    The mechanisms of Al-Si eutectic refinement due to scandium (Sc) additions have been studied in an Al-7Si-0.3Mg foundry alloy. The evolution of eutectic microstructure is studied by thermal analysis and interrupted solidification, and the distribution of Sc is studied by synchrotron micro-XRF mapping. Sc is shown to cause significant refinement of the eutectic silicon. The results show that Sc additions strongly suppress the nucleation of eutectic silicon due to the formation of ScP instead of AlP. Sc additions change the macroscopic eutectic growth mode to the propagation of a defined eutectic front from the mold walls opposite to the heat flux direction similar to past work with Na, Ca, and Y additions. It is found that Sc segregates to the eutectic aluminum and AlSi2Sc2 phases and not to eutectic silicon, suggesting that impurity-induced twinning does not operate. The results suggest that Sc refinement is mostly caused by the significantly reduced silicon nucleation frequency and the resulting increase in mean interface growth rate.

  7. In vitro bioactivity investigation of alkali treated Ti6Al7Nb alloy foams

    NASA Astrophysics Data System (ADS)

    Butev, Ezgi; Esen, Ziya; Bor, Sakir

    2015-02-01

    Biocompatible Ti6Al7Nb alloy foams with 70% porosity manufactured by space holder method were activated via alkali treatment using 5 M NaOH solution at 60 °C. The interconnected pore structures enabled formation of homogenous sodium rich coating on the foam surfaces by allowing penetration of alkali solution throughout the pores which had average size of 200 μm. The resulted coating layer having 500 nm thickness exhibited porous network morphology with 100 nm pore size. On the other hand, heat treatment conducted subsequent to alkali treatment at 600 °C in air transformed sodium rich coating into crystalline bioactive sodium titanate phases. Although the coatings obtained by additional heat treatment were mechanically stable and preserved their morphology, oxidation of the samples deteriorated the compressive strength significantly without affecting the elastic modulus. However, heat treated samples revealed better hydroxyapatite formation when soaked in simulated body fluid (SBF) compared to alkali treated foams. On the other hand, untreated surfaces containing bioactive TiO2 layer were observed to comprise of Ca and P rich precipitates only rather than hydroxyapatite within 15 days. The apatite formed on the treated porous surfaces was observed to have flower-like structure with Ca/P ratio around 1.5 close to that of natural bone.

  8. Procalcitonin (PCT) and C-reactive Protein (CRP) as severe systemic infection markers in febrile neutropenic adults

    PubMed Central

    Massaro, Karin SR; Costa, Silvia F; Leone, Claudio; Chamone, Dalton AF

    2007-01-01

    Background Procalcitonin (PCT) is an inflammatory marker that has been used as indicator of severe bacterial infection. We evaluated the concentrations of PCT as a marker for systemic infection compared to C-reactive protein (CRP) in patients neutropenic febrile. Methods 52 adult patients were enrolled in the study. Blood sample was collected in order to determine the serum concentrations of PCT, CRP and other hematological parameters at the onset of fever. The patients were divided into 2 groups, one with severe infection (n = 26) and the other in which the patients did not present such an infection (n = 26). Then PCT and CRP concentrations at the fever onset were compared between groups using non parametric statistical tests, ROC curve, sensitivity, specificity, likelihood ratio, and Spearman's correlation coefficient. Results The mean of PCT was significantly higher in the group with severe infection (6.7 ng/mL versus 0.6 ng/mL – p = 0.0075) comparing with CRP. Serum concentrations of 0.245 ng/mL of PCT displayed 100% de sensitivity and 69.2% specificity. PCT concentrations of 2,145 ng/mL presented a likelihood ratio of 13, which was not observed for any concentration of CRP. Conclusion PCT seems to be an useful marker for the diagnosis of systemic infection in febrile neutropenic patients, probably better than CRP. PMID:18034890

  9. Nuclear waste glass product consistency test (PCT): Version 7.0. Revision 3

    SciTech Connect

    Jantzen, C.M.; Bibler, N.E.; Beam, D.C.; Ramsey, W.G.

    1994-06-01

    Liquid high-level nuclear waste will be immobilized at the Savannah River Site (SRS) by vitrification in borosilicate glass. The glass will be produced in the Defense Waste Processing Facility (DWPF), poured into stainless steel canisters, and eventually disposed of in a geologic repository. In order to comply with the Waste Acceptance Product Specifications (WAPS), the durability of the glass needs to be measured during production to assure its long term stability and radionuclide release properties. A durability test, designated the Product Consistency Test (PCT), was developed for DWPF glass in order to meet the WAPS requirements. The response of the PCT procedure was based on extensive testing with glasses of widely different compositions. The PCT was determined to be very reproducible, to yield reliable results rapidly, and to be easily performed in shielded cell facilities with radioactive samples. Version 7.0 of the PCT procedure is attached. This draft version has been submitted to ASTM for full committee (C26, Nuclear Fuel Cycle) ballot after being balloted successfully through subcommittee C26.13 on Repository Waste Package Materials Testing.

  10. On the Potential of Using the Al7 Superatom as an Excess Electron Acceptor To Construct Materials with Excellent Nonlinear Optical Properties.

    PubMed

    Huang, Shaoyuan; Liao, Kuntian; Peng, Bin; Luo, Qiong

    2016-05-01

    With the aid of density functional theory (DFT) calculations, we found that, when alkali metal approaches the Al7 superatom, its outermost s-value electron can be trapped by Al7 to give the superatom compound MAl7 (M = Li, Na, K) with an excess electron. Different analyses including natural bond orbital (NBO), electron localization function (ELF), and energy decomposition analysis (EDA) show that the resulting M-Al bond is strong and has a polar covalent character. The optimizations of self-assemblies (MAl7)n (n = 2, 3) have been performed to explore the stability of MAl7 in the solid state. The results reveal that only NaAl7 can keep its structural integrity as a building block upon self-assembling, while serious aggregations between Al7 clusters occur in the dimers and trimers of LiAl7 and KAl7, despite the fact that the Li-Al7 and K-Al7 bond energies are comparable to that of Na-Al7. Born-Oppenheimer molecular dynamics (BOMD) simulations for (NaAl7)n (n = 2, 3) indicate that these species are stable toward fragmentation at 300 K. The β0 values of (NaAl7)n (n = 1, 2, and 3) predicted at the CAM-B3LYP/6-311+G(3df) level of theory are in the range of 1.6 × 10(4)a.u. to 7.5 × 10(4) a.u.. This theoretical study implies that NaAl7 is a promising candidate for nolinear optical (NLO) materials. We provide theoretical evidence for the possibility of using the Al7 superatom as an excess electron acceptor to construct materials with excellent NLO properties. Further experimental research is invited. PMID:27064431

  11. Interconnection between microstructure and microhardness of directionally solidified binary Al-6wt.%Cu and multicomponent Al-6wt.%Cu-8wt.%Si alloys.

    PubMed

    Vasconcelos, Angela J; Kikuchi, Rafael H; Barros, André S; Costa, Thiago A; Dias, Marcelino; Moreira, Antonio L; Silva, Adrina P; Rocha, Otávio L

    2016-05-31

    An experimental study has been carried out to evaluate the microstructural and microhardness evolution on the directionally solidified binary Al-Cu and multicomponent Al-Cu-Si alloys and the influence of Si alloying. For this purpose specimens of Al-6wt.%Cu and Al-6wt.%Cu-8wt.%Si alloys were prepared and directionally solidified under transient conditions of heat extraction. A water-cooled horizontal directional solidification device was applied. A comprehensive characterization is performed including experimental dendrite tip growth rates (VL) and cooling rates (TR) by measuring Vickers microhardness (HV), optical microscopy and scanning electron microscopy with microanalysis performed by energy dispersive spectrometry (SEM-EDS). The results show, for both studied alloys, the increasing of TR and VL reduced the primary dendrite arm spacing (l1) increasing the microhardness. Furthermore, the incorporation of Si in Al-6wt.%Cu alloy to form the Al-6wt.%Cu-8wt.%Si alloy influenced significantly the microstructure and consequently the microhardness but did not affect the primary dendritic growth law. An analysis on the formation of the columnar to equiaxed transition (CET) is also performed and the results show that the occurrence of CET is not sharp, i.e., the CET in both cases occurs in a zone rather than in a parallel plane to the chill wall, where both columnar and equiaxed grains are be able to exist. PMID:27254454

  12. Genotype-phenotype associations in WT1 glomerulopathy.

    PubMed

    Lipska, Beata S; Ranchin, Bruno; Iatropoulos, Paraskevas; Gellermann, Jutta; Melk, Anette; Ozaltin, Fatih; Caridi, Gianluca; Seeman, Tomas; Tory, Kalman; Jankauskiene, Augustina; Zurowska, Aleksandra; Szczepanska, Maria; Wasilewska, Anna; Harambat, Jerome; Trautmann, Agnes; Peco-Antic, Amira; Borzecka, Halina; Moczulska, Anna; Saeed, Bassam; Bogdanovic, Radovan; Kalyoncu, Mukaddes; Simkova, Eva; Erdogan, Ozlem; Vrljicak, Kristina; Teixeira, Ana; Azocar, Marta; Schaefer, Franz

    2014-05-01

    WT1 mutations cause a wide spectrum of renal and extrarenal manifestations. Here we evaluated disease prevalence, phenotype spectrum, and genotype-phenotype correlations of 61 patients with WT1-related steroid-resistant nephrotic syndrome relative to 700 WT1-negative patients, all with steroid-resistant nephrotic syndrome. WT1 patients more frequently presented with chronic kidney disease and hypertension at diagnosis and exhibited more rapid disease progression. Focal segmental glomerulosclerosis was equally prevalent in both cohorts, but diffuse mesangial sclerosis was largely specific for WT1 disease and was present in 34% of cases. Sex reversal and/or urogenital abnormalities (52%), Wilms tumor (38%), and gonadoblastoma (5%) were almost exclusive to WT1 disease. Missense substitutions affecting DNA-binding residues were associated with diffuse mesangial sclerosis (74%), early steroid-resistant nephrotic syndrome onset, and rapid progression to ESRD. Truncating mutations conferred the highest Wilms tumor risk (78%) but typically late-onset steroid-resistant nephrotic syndrome. Intronic (KTS) mutations were most likely to present as isolated steroid-resistant nephrotic syndrome (37%) with a median onset at an age of 4.5 years, focal segmental glomerulosclerosis on biopsy, and slow progression (median ESRD age 13.6 years). Thus, there is a wide range of expressivity, solid genotype-phenotype associations, and a high risk and significance of extrarenal complications in WT1-associated nephropathy. We suggest that all children with steroid-resistant nephrotic syndrome undergo WT1 gene screening. PMID:24402088

  13. WT1 Expression in the Human Fetus During Development

    PubMed Central

    Ambu, R.; Vinci, L.; Gerosa, C.; Fanni, D.; Obinu, E.; Faa, A.; Fanos, V.

    2015-01-01

    Wilms’ Tumor 1 (WT1) is a transcription factor involved in the development of the urogenital system. The purpose of this study was to analyze the immunoreactivity for WT1 protein in different tissues and organs in human fetuses in early phases of gestation. To this end, samples from multiple organs were obtained from 4 human fetuses, ranging from 7 up to 12 weeks of gestation. Each sample was formalin-fixed, paraffin embedded and immunostained for WT1. Our data show that WT1 is involved in development of multiple human organs in a more vast series of cells types than previously reported. Immunostaining for WT1 was characterized by a predominant cytoplasmic reactivity in the vast majority of cell types. Mesenchimal progenitors in the fetal lung, ductal plate progenitors in fetal liver, cap mesenchimal cells in the developing kidney, fetal zone cells in adrenal glands, atrial and ventricular cardiomyocytes in the fetal heart, radial glial cells in the fetal cerebral cortex and skeletal muscle cell precursors showed the highest levels of WT1 immunoreactivity. Future studies will be needed to detect differences in the expression of WT1 in various organs at different gestational ages, in order to better evaluate the role of WT1 in cell proliferation and differentiation during intrauterine human development. PMID:26150159

  14. Effect of undercooling on the microstructure of Ni-35 at. pct Mo (eutectic) and Ni-38 at. pct Mo (hypereutectic) alloys

    NASA Technical Reports Server (NTRS)

    Tewari, S. N.

    1987-01-01

    Ni-35 at. pct Mo and Ni-38 at. pct Mo alloy specimens have been solidified from various levels of undercooling in the differential thermal analysis and the electromagnetic levitation units in a pyrex/vycor bed. The evolution of the microstructure in the solified specimens has been examined in terms of the degree of undercooling, the nature of the first phase to nucleate from the melt, and the specimen cooling rate. The melt has been observed to undercool more in the presence of intermetallic NiMo (beta) phase as compared to that in the presence of nickel-rich solid solution (gamma). The 'anomalous eutectic' type of microstructure has been shown to result from the initial formation of the dendritic skeleton of either of the two phases, its segmentation due to convection and ripening, and the subsequent nucleation of the other phase in the interdendritic liquid regions. The recalescence behavior has been examined as a function of undercooling and the nature of the phase nucleating first in the melt.

  15. The effect of heat treatments on the corrosion fatigue properties of 13 Pct Chromium Stainless Steel in 3 Pct NaCI Aqueous Solution

    NASA Astrophysics Data System (ADS)

    Ishii, Hitoshi; Sakakibara, Yuji; Ebara, Ryuichiro

    1982-08-01

    The effect of austenitizing or tempering temperature on the corrosion fatigue properties of 13 pct chromium stainless steel was studied. Three pct NaCI aqueous solution was used as the corrosive environment, and the results were compared with the atmospheric fatigue properties. Strong influence of the tempering temperature on the S-N and FCP behavior of this blading material was found. The damage ratios (corrosion fatigue limit divided by endurance limit) of these various heat treated specimens became very low by this environment. Especially, extremely low corrosion fatigue strength of the specimen tempered at 600 °C was noticed. This microstructure was strategically used to clarify the reduction of pH inside the corrosion pits which were generally formed at the fatigue crack initiation sites. FCP data in the corrosive environment showed higher resistance than the atmospheric ones at the stress intensities below 18 MPa · m1/2, and which is opposite to the generally known influence of the corrosive environments. As for the fractographic feature, an appearance of the intergranular facets was especially noticed in NaCI aqueous solution environment. The fraction of this intergranular cracking was obtained as a function of the stress intensity factor.

  16. Investigation of quantum criticality in the new heavy fermion compound Ce2PdAl7Ge4

    NASA Astrophysics Data System (ADS)

    Bauer, Eric; Wakeham, N. A.; Kim, D.; Ghimire, N. J.; Ronning, F.; Movshovich, R.; Thompson, J. D.

    Ce-based intermetallic compounds exhibit a variety of interesting ground states including magnetic order, heavy fermion behavior, unconventional superconductivity, and non-Fermi liquid behavior. When magnetic order is suppressed to T = 0 K, or quantum critical point, by chemical substitution, pressure, or magnetic field, a dome of unconventional superconductivity is often found. Close to the quantum critical point, non-Fermi liquid temperature dependencies of the thermodynamic and transport properties are observed. Recently, a new family of tetragonal Ce2MAl7Ge4 (M =Co, Ni, Pd, Ir) compounds was discovered. While the Ce2MAl7Ge4 (M =Co, Ir, Ni) materials order magnetically between Tm = 0.8 - 1.6 K, Ce2PdAl7Ge4 exhibits non-Fermi liquid behavior at low temperature. Here, we discuss the quantum criticality in Ce2PdAl7Ge4.

  17. a Robust Pct Method Based on Complex Least Squares Adjustment Method

    NASA Astrophysics Data System (ADS)

    Haiqiang, F.; Jianjun, Z.; Changcheng, W.; Qinghua, X.; Rong, Z.

    2013-07-01

    Polarization Coherence Tomography (PCT) method has the good performance in deriving the vegetation vertical structure. However, Errors caused by temporal decorrelation and vegetation height and ground phase always propagate to the data analysis and contaminate the results. In order to overcome this disadvantage, we exploit Complex Least Squares Adjustment Method to compute vegetation height and ground phase based on Random Volume over Ground and Volume Temporal Decorrelation (RVoG + VTD) model. By the fusion of different polarimetric InSAR data, we can use more observations to obtain more robust estimations of temporal decorrelation and vegetation height, and then, we introduce them into PCT to acquire more accurate vegetation vertical structure. Finally the new approach is validated on E-SAR data of Oberpfaffenhofen, Germany. The results demonstrate that the robust method can greatly improve accusation of vegetation vertical structure.

  18. Direct Resistance Joule Heating of Al-10 pct Si-Coated Press Hardening Steel

    NASA Astrophysics Data System (ADS)

    Lee, Chang Wook; Choi, Won Seok; Cho, Yeol Rae; De Cooman, Bruno C.

    2016-06-01

    Various rapid heating methods have been developed to increase the productivity of press hardening steel. One of these methods is direct resistance Joule heating. This heating method results in the melting of the surface coating and the formation of a persistent liquid trail as a result of the high thermal conductivity and low melting temperature of the Al-10 pct Si alloy coating. This can be addressed by an alloying preheating treatment prior to the press hardening process.

  19. Direct Resistance Joule Heating of Al-10 pct Si-Coated Press Hardening Steel

    NASA Astrophysics Data System (ADS)

    Lee, Chang Wook; Choi, Won Seok; Cho, Yeol Rae; De Cooman, Bruno C.

    2016-03-01

    Various rapid heating methods have been developed to increase the productivity of press hardening steel. One of these methods is direct resistance Joule heating. This heating method results in the melting of the surface coating and the formation of a persistent liquid trail as a result of the high thermal conductivity and low melting temperature of the Al-10 pct Si alloy coating. This can be addressed by an alloying preheating treatment prior to the press hardening process.

  20. Serum PCT and its Relation to Body Weight Gain in Pulmonary Tuberculosis.

    PubMed

    Rohini, K; Bhat, Surekha; Srikumar, P S; Mahesh Kumar, A

    2015-07-01

    The present study was aimed at assessing alterations in serum PCT in terms of its relation to body weight gain in pulmonary tuberculosis (PTB) patients undergoing treatment. Among patients (25-75 years) diagnosed with pulmonary tuberculosis, those that were new smear positive, showed sputum conversion at the end of 2 months and were declared clinically cured at the end of 6 months, were included in the study (n = 40). Serum procalcitonin was determined by BRAHMS PCT-Q kit. Patients were divided into two study groups-Group 1 (n = 21; serum PCT > 2 ng/ml at diagnosis), Group 2 (n = 19; serum PCT > 10 ng/ml at diagnosis). Body weights of all patients were obtained at three different time points, PTB-0 (at diagnosis), PTB-2 (after 2 months of intensive treatment) and PTB-6 (after 6 months of treatment). In both groups, mean body weights at PTB-2 and PTB-6 were significantly higher than those at PTB-0 and at PTB-6 were significantly higher than those at PTB-2. However, percentage body weight gain following 2 months of intensive treatment was higher in group 1 (4.05 % gain, p < 0.01) than in group 2 (2.75 % body weight gain, p < 0.05). Thus, the percentage gain in group 1 was tending more towards the desirable minimum gain of 5 % during intensive phase. Increase in serum PCT levels in pulmonary tuberculosis is inversely associated with body weight gain during treatment. Thus, PCT could play a role in regulation of body weight gain in anorectic conditions like tuberculosis. PMID:26089621

  1. Recovery of glucose metabolism in reperfused canine myocardium demonstrated by positron-CT (PCT)

    SciTech Connect

    Schwaiger, M.; Sochor, H.; Parodi, O.; Grover, M.; Hansen, H.W.; Selin, C.; Schelbert, H.R.

    1984-01-01

    The authors previously examined with PCT in chronic dogs the long term metabolic recovery during reperfusion after a 3 hr ischemic insult. Increased regional glucose utilization at 24 hrs of R accurately identified reversible tissue injury documented by late improvement in segmental function by ultrasonic crystals. To define the early metabolic events after a 3 hr LAD balloon occlusion, regional blood flow and glucose utilization was studied in 8 dogs with PCT, N-13 ammonia (NA) and F-18 deoxyglucose (FDG) at 2 hrs and at 24 hrs after R. The dogs were then thoracotomized and MBF by microspheres, arterio-venous differences for glucose, lactate and O/sub 2/ across the reperfused segment (LAD vein) and the left ventricle (coronary sinus) measured. Immediately after reperfusion, MBF and FDG uptake were 27 +- 24% and 21 +- 48% lower in the reperfused territory (RT) than in control myocardium (C). At 24 hrs, MBF by microspheres was and 22 +- 25% lower and FDG uptake 175 +- 73% higher in RT than in C. In the RT, consumption of glucose (by Fick method) was 202 +- 107% higher, of lactate 96 +- 85% lower and of O/sub 2/ 42 +- 26% lower than in the entire LV. PCT measured FDG uptake correlated with glucose consumption (r=0.94) and confirmed that the segmentally increased FDG uptake at 24 hrs reflected increased glucose utilization that, as indicated by the reduced lactate consumption, was partly anaerobic. The authors conclude that initially after R, glucose metabolism is depressed but increases above C within 24 hrs, a time course that now can be determined noninvasively with PCT and is useful for predicting functional recovery.

  2. HTS and PCT Reliability of Chips and Flex Substrates Assembled Using a Thermosonic Flip-Chip Bonding Process

    NASA Astrophysics Data System (ADS)

    Chuang, Cheng-Li; Kang, Min-Yi

    2012-09-01

    This study assesses the high-temperature storage (HTS) test and the pressure-cooker test (PCT) reliability of an assembly of chips and flexible substrates. After the chips were bonded onto the flexible substrates, specimens were utilized to assess the HTS test and PCT reliability. After the PCT and HTS tests, the die-shear test was applied to examine changes in die-shear forces. The microstructure of the test specimens was analyzed to evaluate reliability and to identify possible failure mechanisms. When the duration of the HTS test was increased, the percentage of gold bumps that peeled off from the surface of the copper pads on the chip side increased, and a crack was present at the bonding interface between the gold bumps and chip bond pads. This crack was due to thermal stress generated during the HTS test, and degraded the die-shear force of the assembly of chips and flexible substrates. After the PCT, the crack was present at the interface between deposited layers of copper electrodes after the specimens were subjected to the PCT for various durations. Moisture penetrated into the deposited layers of the copper electrodes, deposited layers lost their adhesion, and the crack progressed from the corner into the central bond area as the test duration increased. To improve the PCT reliability of assemblies of chips and flexible substrates using the thermosonic flip-chip bonding process, one must prevent moisture from penetrating into deposited layers of copper electrodes and prevent crack formation at the interface between nickel and copper layers. Underfill would be an effective approach to prevent moisture from penetrating into deposited layers during the PCT, thereby improving the reliability of the samples during the PCT.

  3. The Effect of Ti on Mechanical Properties of Extruded In-Situ Al-15 pct Mg2Si Composite

    NASA Astrophysics Data System (ADS)

    Soltani, Niloofar; Bahrami, Amin; Pech-Canul, Martin Ignacio

    2013-09-01

    This work was carried out to investigate the effect of different Ti concentrations as a modifying agent on the microstructure and tensile properties of an in-situ Al-15 pctMg2Si composite. Cast, modified, and homogenized small ingots were extruded at 753 K (480 °C) at the extrusion ratio of 18:1 and ram speed of 1 mm/s. Various techniques including metallography, tensile testing, and scanning electron microscopy were used to characterize the mechanical behavior, microstructural observations, and fracture mechanisms of this composite. The results showed that 0.5 pctTi addition and homogenizing treatment were highly effective in modifying Mg2Si particles. The results also exhibited that the addition of Ti up to 0.5 pct increases both ultimate tensile strength (UTS) and tensile elongation values. The highest UTS and elongation values were found to be 245 MPa and 9.5 pct for homogenized and extruded Al-15 pctMg2Si-0.5 pctTi composite, respectively. Fracture surface examinations revealed a transition from brittle fracture mode in the as-cast composite to ductile fracture in homogenized and extruded specimens. This can be attributed to the changes in size and morphology of Mg2Si intermetallic and porosity content.

  4. Just how strapping was KNM-WT 15000?

    PubMed

    Graves, Ronda R; Lupo, Amy C; McCarthy, Robert C; Wescott, Daniel J; Cunningham, Deborah L

    2010-11-01

    For over twenty years, the young, male Homo erectus specimen KNM-WT 15000 has been the focus of studies on growth and development, locomotion, size, sexual dimorphism, skeletal morphology, and encephalization, often serving as the standard for his species. Prior research on KNM-WT 15000 operates under the assumption that H. erectus experienced a modern human life history, including an adolescent growth spurt. However, recent fossil discoveries, improvements in research methods, and new insights into modern human ontogeny suggest that this may not have been the case. In this study, we examine alternative life history trajectories in H. erectus to re-evaluate adult stature estimates for KNM-WT 15000. We constructed a series of hypothetical growth curves by modifying known human and chimpanzee curves, calculating intermediate growth velocities, and shifting the age of onset and completion of growth in stature. We recalculated adult stature for KNM-WT 15000 by increasing stature at death by the percentage of growth remaining in each curve. The curve that most closely matches the life history events experienced by KNM-WT 15000 prior to death indicates that growth in this specimen would have been completed by 12.3 years of age. These results suggest that KNM-WT 15000 would have experienced a growth spurt that had a lower peak velocity and shorter duration than the adolescent growth spurt in modern humans. As a result, it is likely that KNM-WT 15000 would have only attained an adult stature of 163 cm (∼ 5'4 ″), not 185 cm (∼ 6'1 ″) as previously reported. KNM-WT 15000's smaller stature has important implications for evolutionary scenarios involving early genus Homo. PMID:20846707

  5. Equiaxed and columnar dendrite growth simulation in Al-7Si- Mg ternary alloys using cellular automaton method

    NASA Astrophysics Data System (ADS)

    Chen, Rui; Xu, Qingyan; Liu, Baicheng

    2015-06-01

    In this paper, a modified cellular automaton (MCA) model allowing for the prediction of dendrite growth of Al-Si-Mg ternary alloys in two and three dimensions is presented. The growth kinetic of S/L interface is calculated based on the solute equilibrium approach. In order to describe the dendrite growth with arbitrarily crystallographic orientations, this model introduces a modified decentered octahedron algorithm for neighborhood tracking to eliminate the effect of mesh dependency on dendrite growth. The thermody namic and kinetic data needed for dendrite growth is obtained through coupling with Pandat software package in combination with thermodynamic/kinetic/equilibrium phase diagram calculation databases. The effect of interactions between various alloying elements on solute diffusion coefficient is considered in the model. This model has first been used to simulate Al-7Si (weight percent) binary dendrite growth followed by a validation using theoretical predictions. For ternary alloy, Al-7Si-0.5Mg dendrite simulation has been carried out and the effects of solute interactions on diffusion matrix as well as the differences of Si and Mg in solute distribution have been analyzed. For actual application, this model has been applied to simulate the equiaxed dendrite growth with various crystallographic orientations of Al-7Si-0.36Mg ternary alloy, and the predicted secondary dendrite arm spacing (SDAS) shows a reasonable agreement with the experimental ones. Furthermore, the columnar dendrite growth in directional solidification has also been simulated and the predicted primary dendrite arm spacing (PDAS) is in good agreement with experiments. The simulated results effectively demonstrate the abilities of the model in prediction of dendritic microstructure of Al-Si-Mg ternary alloy.

  6. Effects of Mo on microstructure of as-cast 28 wt.% Cr–2.6 wt.% C–(0–10) wt.% Mo irons

    SciTech Connect

    Imurai, S.; Thanachayanont, C.; Pearce, J.T.H.; Tsuda, K.; Chairuangsri, T.

    2014-04-01

    Microstructures of as-cast 28 wt.% Cr–2.6 wt.% C irons containing (0–10) wt.% Mo with the Cr/C ratio of about 10 were studied and related to hardness. The experimental irons were cast into dry sand molds. Microstructural investigation was performed by light microscopy, X-ray diffractometry, scanning electron microscopy, transmission electron microscopy and energy-dispersive X-ray spectrometry. It was found that the iron with about 10 wt.% Mo was eutectic/peritectic, whereas the others with less Mo content were hypoeutectic. The matrix in all irons was austenite, partly transformed to martensite during cooling. Mo addition promoted the formation of M{sub 23}C{sub 6} and M{sub 6}C. At 1 wt.% Mo, multiple eutectic carbides including M{sub 7}C{sub 3}, M{sub 23}C{sub 6} and M{sub 6}C were observed. M{sub 23}C{sub 6} existed as a transition zone between eutectic M{sub 7}C{sub 3} and M{sub 6}C, indicating a carbide transition as M{sub 7}C{sub 3}(M{sub 2.3}C) → M{sub 23}C{sub 6}(M{sub 3.8}C) → M{sub 6}C. At 6 wt.% Mo, multiple eutectic carbides including M{sub 7}C{sub 3} and M{sub 23}C{sub 6} were observed together with fine cellular/lamellar M{sub 6}C aggregates. In the iron with 10 wt.% Mo, only eutectic/peritectic M{sub 23}C{sub 6} and M{sub 6}C were found without M{sub 7}C{sub 3}. Mo distribution to all carbides has been determined to be increased from ca. 0.4 to 0.7 in mass fraction as the Mo content in the irons was increased. On the other hand, Cr distribution to all carbides is quite constant as ca. 0.6 in mass fraction. Mo addition increased Vickers macro-hardness of the irons from 495 up to 674 HV{sub 30}. High Mo content as solid-solution in the matrix and the formation of M{sub 6}C or M{sub 23}C{sub 6} aggregates were the main reasons for hardness increase, indicating potentially improved wear performance of the irons with Mo addition. - Highlights: • Mo promoted the formation of M{sub 23}C{sub 6} and M{sub 6}C in the irons with Cr/C ratio of about 10

  7. Effects of W on microstructure of as-cast 28 wt.%Cr–2.6 wt.%C–(0–10)wt.%W irons

    SciTech Connect

    Imurai, S.; Thanachayanont, C.; Pearce, J.T.H.; Tsuda, K.; Chairuangsri, T.

    2015-01-15

    Microstructures of as-cast 28 wt.%Cr–2.6 wt.%C irons containing (0–10)wt.%W with the Cr/C ratio about 10 were studied and related to their hardness. The experimental irons were cast into dry sand molds. Microstructural investigation was performed by light microscopy, X-ray diffractometry, scanning electron microscopy, transmission electron microscopy and energy-dispersive X-ray spectrometry. It was found that the irons with 1 to 10 wt.%W addition was hypereutectic containing large primary M{sub 7}C{sub 3}, whereas the reference iron without W addition was hypoeutectic. The matrix in all irons was austenite, partly transformed to martensite during cooling. The volume fractions of primary M{sub 7}C{sub 3} and the total carbides increased, but that of eutectic carbides decreased with increasing the W content of the irons. W addition promoted the formation of W-rich M{sub 7}C{sub 3}, M{sub 6}C and M{sub 23}C{sub 6}. At about 4 wt.%W, two eutectic carbides including M{sub 7}C{sub 3} and M{sub 6}C were observed together with primary M{sub 7}C{sub 3}. At 10 wt.%W, multiple carbides including primary M{sub 7}C{sub 3}, fish-bone M{sub 23}C{sub 6}, and M{sub 6}C were observed. M{sub x}C where x = 3 or less has not been found due possibly to the high M/C ratio in the studied irons. W distribution to all carbides has been determined increasing from ca. 0.3 to 0.8 in mass fraction as the W content in the irons was increased. W addition led to an increase in Vickers macro-hardness of the irons up to 671 kgf/(mm){sup 2} (HV30/15) obtained from the iron with 10 wt.%W. The formation of primary M{sub 7}C{sub 3} and aggregates of M{sub 6}C and M{sub 23}C{sub 6} were the main reasons for hardness increase, indicating potentially improved wear performance of the as-cast irons with W addition. - Highlights: • W addition at 1 up to 10 wt.%W to Fe–28Cr–2.6C produced “hypereutectic” structure. • W addition promoted the formation of W-rich M{sub 7}C{sub 3}, M{sub 6}C and M

  8. The attack of titanium-6 wt% aluminium-4 wt% vanadium alloy by a molten uranium-5.7 wt% manganese alloy at 1015 °C

    NASA Astrophysics Data System (ADS)

    Moran, F. J.; Jarman, R. A.

    1991-06-01

    The liquid metal corrosion (LMC) resistance of the alloy Ti-6 wt% Al-4 wt% V (IMI 318) in contact with molten U-5.7 wt% Mn has been assessed. The uranium alloy was melted at 1015 °C under vacuum in hemispherical IMI 318 alloy crucibles. The attack rate of the molten alloy on the IMI 318, for times up to 3 h, was estimated from metallography and by chemical analysis of the resolidified uranium melt. The mechanism of the LMC process was examined with optical and electron microscopy allied with EDAX and microhardness tests. Melt saturation occurred after one hour and titanium-rich (approximately 80 wt% Ti) dendrites began to nucleate and grow in the uranium melt. This result was predicted by the relevant equilibrium phase diagrams. During the LMC reaction, an interface (diffusion) layer grew in IMI 318 alloy where it contacted the uranium alloy melt. The levels of Ti and U changed with test time and distance across this interface, with the Ti level falling at the melt/IMI 318 surface and the U increasing at the same point. The mean LMC rate was initially rapid, 1.45 mm/h after 15 min but fell to 0.3 mm/h at 3 h. The conclusions were that the LMC reaction was diffusion-controlled, with the slow self-diffusion of β-titanium most likely to be the rate determining step. The reaction probably follows parabolic rate-kinetics as do other diffusion-controlled processes. The attack front was generally uniform with no clear evidence of preferential attack.

  9. Atom probe field ion microscopy investigation of boron containing martensitic 9 Pct chromium steel

    NASA Astrophysics Data System (ADS)

    Hofer, P.; Miller, M. K.; Babu, S. S.; David, S. A.; Cerjak, H.

    2000-03-01

    The chemical compositions of the ferrite matrix and various other phases in an Fe-0.17 C-9 Cr-1.55 Mo-0.27 V-0.015 N-0.01B (mass pct) steel in as-received and crept conditions were measured with atom probe field ion microscopy (APFIM). The results showed the presence of some residual boron within the ferrite matrix. Analyses showed that boron was distributed within M23C6, M6C, MX, and Laves phases. Phosphor atoms were detected at the M23C6-ferrite interface in the crept condition. The results are compared to predictions from thermodynamic calculations.

  10. Experimental Determination of the Phase Diagram of the CaO-SiO2-5 pctMgO-10 pctAl2O3-TiO2 System

    NASA Astrophysics Data System (ADS)

    Shi, Junjie; Sun, Lifeng; Zhang, Bo; Liu, Xuqiang; Qiu, Jiyu; Wang, Zhaoyun; Jiang, Maofa

    2016-02-01

    Ti-bearing CaO-SiO2-MgO-Al2O3-TiO2 slags are important for the smelting of vanadium-titanium bearing magnetite. In the current study, the pseudo-melting temperatures were determined by the single-hot thermocouple technique for the specified content of 5 to 25 pct TiO2 in the CaO-SiO2-5 pctMgO-10 pctAl2O3-TiO2 phase diagram system. The 1573 K to 1773 K (1300 °C to 1500 °C) liquidus lines were first calculated based on the pseudo-melting temperatures according to thermodynamic equations in the specific primary crystal field. The phase equilibria at 1573 K (1300 °C) were determined experimentally using the high-temperature equilibrium and quench method followed by X-ray fluorescence, X-ray diffraction, scanning electron microscope, and energy dispersive X-ray spectroscope analysis; the liquid phase, melilite solid solution phase (C2MS2,C2AS)ss, and perovskite phase of CaO·TiO2 were found. Therefore, the phase diagram was constructed for the specified region of the CaO-SiO2-5 pctMgO-10 pctAl2O3-TiO2 system.

  11. How much more would KNM-WT 15000 have grown?

    PubMed

    Ruff, Christopher B; Burgess, M Loring

    2015-03-01

    Because of its completeness, the juvenile Homo ergaster/erectus KNM-WT 15000 has played an important role in studies of the evolution of body form in Homo. Early attempts to estimate his adult body size used modern human growth models. However, more recent evidence, particularly from the dentition, suggests that he may have had a more chimpanzee-like growth trajectory. Here we re-estimate his adult stature and body mass using ontogenetic data derived from four African ape taxa: Pan troglodytes troglodytes, Pan troglodytes schweinfurthii, Pan paniscus, and Gorilla gorilla gorilla. The average percentage change in femoral and tibial lengths and femoral head breadth between individuals at the same stage of dental development as KNM-WT 15000 - eruption of M2s but not M3s - and adult individuals with fully fused long bone epiphyses, was determined. Results were then applied to KNM-WT 15000, and his adult size estimated from skeletal dimensions using modern human prediction formulae. Using this approach, adult stature best estimates of 176-180 cm and body mass best estimates of 80-83 kg were obtained. These estimates are close to those estimated directly from longitudinal changes in body length and body mass between 8 and 12 years of age in chimpanzees, the suggested chronological equivalent to KNM-WT 15000's remaining growth period. Thus, even using an African ape growth model, it is likely that KNM-WT 15000 would have attained close to 180 cm in stature (without a slight reduction for his lower cranial height) and 80 kg in body mass as an adult. Other evidence from the East African Early Pleistocene indicates that KNM-WT 15000 was not unusually large-bodied for his time period. PMID:25449954

  12. TRIGA high wt -% LEU fuel development program. Final report

    SciTech Connect

    West, G.B.

    1980-07-01

    The principal purpose of this work was to investigate the characteristics of TRIGA fuel where the contained U-235 was in a relatively high weight percent (wt %) of LEU (low enriched uranium - enrichment of less than 20%) rather than a relatively low weight percent of HEU (high enriched uranium). Fuel with up to 45 wt % U was fabricated and found to be acceptable after metallurgical examinations, fission product retention tests and physical property examinations. Design and safety analysis studies also indicated acceptable prompt negative temperature coefficient and core lifetime characteristics for these fuels.

  13. Conversion of a rabbit proximal convoluted tubule (PCT) into a cell monolayer: ultrastructural study of cell dedifferentiation and redifferentiation.

    PubMed

    Koechlin, N; Pisam, M; Poujeol, P; Tauc, M; Rambourg, A

    1991-04-01

    The evolution of a primary culture of kidney proximal convoluted tubule (PCT) cells was followed step by step from the plating time of an isolated tubule to the 39th day of culture. During the first 48 h, the structural remodeling of PCT, leading to the formation of a cell monolayer without cell division, is accompanied by intracytoplasmic changes indicating cell dedifferentiation. Numerous autophagic vacuoles are observed inside the cells, and the ultrastructural features characteristic of in situ PCT cells are progressively lost. Despite these drastic modifications, cell polarity, as observed by immunocytochemical detection of the leucine aminopeptidase, remains unaltered. Starting at 48 h, the peripheral cells divide, and the culture proliferates in a centrifugal direction while newly formed cells differentiate. From 6 days onwards, glycogen granules, never encountered in in situ PCT cells, appear in cultured cells and progressively accumulate. At the optimal stage of the culture (12-17 days old), cells somewhat resemble PCT cells, but their apical brush borders remain rudimentary, and basal cytoplasmic interdigitations surrounding densely packed mitochondria are poorly developed. Subsequently, the cells become overloaded with glycogen and lipid inclusions and resemble degenerating cells. PMID:1879437

  14. Physical properties of the Ce2M Al 7Ge4 heavy-fermion compounds (M =Co,Ir,Ni,Pd)

    NASA Astrophysics Data System (ADS)

    Ghimire, N. J.; Cary, S. K.; Eley, S.; Wakeham, N. A.; Rosa, P. F. S.; Albrecht-Schmitt, T.; Lee, Y.; Janoschek, M.; Brown, C. M.; Civale, L.; Thompson, J. D.; Ronning, F.; Bauer, E. D.

    2016-05-01

    We report the synthesis, crystal structure, and characterization by means of single-crystal x-ray diffraction, neutron powder diffraction, and magnetic, thermal, and transport measurements of the new heavy-fermion compounds Ce2MAl 7Ge4 (M =Co,Ir,Ni,Pd). These compounds crystallize in a noncentrosymmetric tetragonal space group P 4 ¯21m , consisting of layers of square nets of Ce atoms separated by Ge-Al and M-Al-Ge blocks. Ce2CoAl7Ge4,Ce2IrAl7Ge4 , and Ce2NiAl7Ge4 order magnetically below TM= 1.8 , 1.6, and 0.8 K, respectively. There is no evidence of magnetic ordering in Ce2PdAl7Ge4 down to 0.4 K. The small amount of entropy released in the magnetic state of Ce2M Al7Ge4 (M = Co, Ir, Ni) and the reduced specific heat jump at TM suggest a strong Kondo interaction in these materials. Ce2PdAl7Ge4 shows non-Fermi liquid behavior, possibly due to the presence of a nearby quantum critical point.

  15. Microstructure of a Creep-Resistant 10 Pct Chromium Steel Containing 250 ppm Boron

    NASA Astrophysics Data System (ADS)

    Golpayegani, Ardeshir; Liu, Fang; Svensson, Henrik; Andersson, Marcus; Andrén, Hans-Olof

    2011-04-01

    The microstructure of a trial martensitic chromium steel containing a high content of boron (250 ppm) was characterized in detail in the as-tempered and aged conditions. This steel has a similar composition and heat treatment as the TAF steel that still is unsurpassed in creep strength among all 9 to 12 pct chromium steels. Characterization was performed by using scanning electron microscopy, energy-filtered transmission electron microscopy, secondary ion mass spectroscopy, and atom probe tomography. Focus was placed on investigating different types of precipitates that play a key role in improving the creep resistance of these steels. The low tempering temperature of 963 K (690 °C) is enough for the precipitation of the full volume fraction of both MX and M23C6. A high boron content, more than 1 at. pct, was found in M23C6 precipitates and they grow slowly during aging. The high boron level in the steel results in metal borides rather than BN with the approximate formula (Mo0.66Cr0.34)2(Fe0.75V0.25)B2. Two families of MX precipitates were found, one at lath boundaries about 35 nm in size and one dense inside the laths, only 5 to 15 nm in size.

  16. The PRIMA collaboration: Preliminary results in FBP reconstruction of pCT data

    NASA Astrophysics Data System (ADS)

    Vanzi, Eleonora; Bruzzi, Mara; Bucciolini, Marta; Cirrone, G. A. Pablo; Civinini, Carlo; Cuttone, Giacomo; Lo Presti, Domenico; Pallotta, Stefania; Pugliatti, Cristina; Randazzo, Nunzio; Romano, Francesco; Scaringella, Monica; Sipala, Valeria; Stancampiano, Concetta; Talamonti, Cinzia; Zani, Margherita

    2013-12-01

    A first prototype of proton Computed Tomography (pCT) scanner, made of four planes and a calorimeter, has been developed by the PRIMA (PRoton IMAging) Italian collaboration and first results concerning tomographic image reconstruction of experimentally acquired data are discussed in this paper. The Filtered Back-Projection (FBP) algorithm was used to reconstruct projections of a phantom acquired with a 62 MeV proton beam. Image noise and spatial resolution were assessed for different parameters of the filter used, with and without selection strategies on proton directions. A satisfactory image quality (0.88 mm resolution and 2.5% noise) was achieved even when the backprojection line was defined using only the line connecting the impact points on the second and third planes and all the data were used, irrespective of the proton direction and residual energy. Probably due to the specific detector-phantom arrangement used in this experiment and due to the substantial reduction of the number of useful events, cuts on proton directions did not increase the image resolution significantly. The results confirm the good performances of the PRIMA scanner prototype. They also demonstrate that FBP can produce images of sufficient quality to be used for patient positioning and to initialize iterative pCT reconstruction methods.

  17. Mechanical properties of Al-60 Pct SiC p composites alloyed with Mg

    NASA Astrophysics Data System (ADS)

    Ahlatci, H.; Çimenoğlu, H.; Candan, E.

    2004-07-01

    In the present work, the effect of an Mg addition on the mechanical properties of the Al-60 vol pct SiC p composites were investigated by uniaxial compression, three-point bending, impact and wear tests (composite-metal and composite-abrasive types). The composites were produced by the pressure-infiltration technique. The composition of the Al matrix was varied between 0 and 8 pct Mg. The mean diameter of the SiC particles was 23 µm. Upon addition of Mg, Mg2Si precipitated in the matrix and the amount of the porosity dramatically decreased. Mg-alloyed-matrix composites exhibited higher strength, lower toughness, and higher wear resistance than pure-Al-matrix composites. During composite-metal wear testing, wear progressed in two sequential periods (running-in and steady state). Weight loss during wear testing decreased with increasing Mg content of the matrix. The degree of improvement of abrasive resistance depended on the abrasive-grain size. Above 200 °C, the composite-abrasive wear resistance decreased with increasing test temperature for all materials.

  18. Comparison of TCLP and long-term PCT performance on low-level mixed waste glasses

    SciTech Connect

    Cicero, C.A.; Andrews, M.K.; Bickford, D.F.

    1994-06-01

    The Mixed Waste Integrated Program (MWIP) of the US Department of Energy (DOE) is currently investigating technologies for conversion of low-level mixed waste (LLMW) into a form suitable for permanent disposal. Vitrification is one of the preferred technologies since it is capable of consistently producing a durable, leach resistant wasteform, while simultaneously minimizing disposal volumes. Since vitrification of LLMW is a relatively new concept, final wasteform specifications have not been developed. The Savannah River Technology Center (SRTC) of the Westinghouse Savannah River Company (WSRC) has developed the Product Consistency Test (PCI), which is a 7-day leaching procedure for glass. Comparison indicates that both tests have merit where LLMW glasses are concerned. The TCLP is an important test for determining the release of metals and for allowing the wasteform to be delisted while the PCT is more useful for determining consistent production of durable glass. It is a better indicator of the behavior of glass in disposal site conditions. Most aggressive leaching of common oxide glasses occurs under caustic rather than acidic conditions, therefore it is necessary to perform both tests. Further tests will be conducted using additional glass compositions and variations in the TCLP and the PCT.

  19. Importance of correction for intravascular radioactivity in dynamic PCT studies using glucose analogs

    SciTech Connect

    Koeppe, R.A.; Holden, J.E.; Hutchins, G.D.

    1985-05-01

    Recently, there has been considerable controversy concerning the accuracy of single scan approaches for estimating glucose metabolic rate. An alternative is to acquire a dynamic sequence of PCT data to estimate the individual rate constants of the conventional 4-parameters model. A model developed that accounts not only for the arterial blood radioactivity, but also for the venous blood radioactivity which itself depends on the local blood flow value, the individual plasma and RBC components of the blood radioactivity, the hematocrit, and the transport rate constants k/sub 1/ and k/sub 2/. Computer simulations predict overestimation in k/sub 1/, k/sub 2/ and k/sub 3/ of 30%, 40%, and 20%, respectively. The overestimation in the estimated metabolic rate, which is proportional to the term k/sub 1/k/sub 3//(k/sub 2/+k/sub 3/), was less than 16%. Parameter values for PCT studies on human subjects using 2-FDG and 3-FDG were evaluated with and without corrections for blood-horns radioactivity. Percent overestimations were similar for both analogs. Results from human studies are in good agreement with those predicted by computer simulation.

  20. Mechanical Property and Corrosion Resistance Evaluations of Ti-6Al-7Nb Alloy Brazed with Bulk Metallic Glasses

    SciTech Connect

    Miura, E.; Kato, H.; Ogata, Toshiaki; Nishiyama, Nobuyuki; Specht, Eliot D; Shiraishi, Takanobu; Inoue, A.; Hisatsune, K.

    2007-01-01

    Exploitation of metallic glass as new brazing filler for Ti-based biomedical alloy was attempted. Ti-6Al-7Nb was used as a brazed material, and candidates of bulk metallic glass brazing filler were Cu60Hf25Ti15, Mg65Cu25Gd10, Zr55Cu30Al10Ni5 and Pd40Cu30P20Ni10. Convergence infrared-ray brazing was conducted for brazing Ti-6Al-7Nb/metallic glass in Ar atmosphere. After brazing, hardness measurement, X-ray tomography, cross-sectional observation, artificial saliva immersion test and tensile test were performed to evaluate brazability, mechanical property and corrosion resistance of the obtained brazing joints. The results of brazing using these metallic glass fillers show that all the metallic glasses were brazable to Ti-6Al-7Nb except for Mg65Cu25Gd10. Mg65Cu25Gd10, Cu60Hf25Ti15 and their joints collapsed rapidly during immersion test. Zr55Cu30Al10Ni5 joint was the best in terms of degradation resistance; however, tensile strength was inferior to the conventional one. Pd40Cu30Ni10P20 filler and Zr55Cu30Al10Ni5 filler and their joints did not show any collapse or tarnish during the immersion test. Pd40Cu30Ni10P20 joint showed the excellent properties in terms of both corrosion resistance and tensile strength, which were superior to a joint brazed using Ti-15Cu-25Ni conventional filler. X-ray tomograph indicates that fracture tends to occur in the vicinity of the brazing interface after tensile test. The brazed metallic glass fillers were fully crystallized, excluding Pd40Cu30Ni10P20 filler. Pd40Cu30Ni10P20 brazed filler contained mapleleaf like primary dendrite, peritectoid and a few microns interfacial reaction layer in glassy matrix. The results indicated that Pd40Cu30Ni10P20 is promising brazing filler for dental or biomaterial devices.

  1. Influence of UFG structure formation on mechanical and fatigue properties in Ti-6Al-7Nb alloy

    NASA Astrophysics Data System (ADS)

    Polyakova, V. V.; Anumalasetty, V. N.; Semenova, I. P.; Valiev, R. Z.

    2014-08-01

    Ultrafine-grained (UFG) Ti alloys have potential applications in osteosynthesis and orthopedics due to high bio-compatibility and increased weight-to- strength ratio. In current study, Ti6Al7Nb ELI alloy is processed through equal channel angular pressing-conform (ECAP-Conform) and subsequent thermomechanical processing to generate a UFG microstructure. The fatigue properties of UFG alloys are compared to coarse grained (CG) alloys. Our study demonstrates that the UFG alloys with an average grain size of ~180 nm showed 35% enhancement of fatigue endurance limit as compared to coarse-grained alloys. On the fracture surfaces of the UFG and CG samples fatigue striations and dimpled relief were observed. However, the fracture surface of the UFG sample looks smoother; fewer amounts of secondary micro-cracks and more ductile rupture were also observed, which testifies to the good crack resistance in the UFG alloy after high-cyclic fatigue tests.

  2. Spin-foam fermions: PCT symmetry, Dirac determinant and correlation functions

    NASA Astrophysics Data System (ADS)

    Han, Muxin; Rovelli, Carlo

    2013-04-01

    We discuss fermion coupling in the framework of spin-foam quantum gravity. We analyze the gravity-fermion spin-foam model and its fermion correlation functions. We show that there is a spin-foam analogue of PCT symmetry for the fermion fields on a spin-foam model, which is proved for spin-foam fermion correlation functions. We compute the determinant of the Dirac operator for the fermions, where two presentations of the Dirac determinant are given in terms of diagram expansions. We compute the fermion correlation functions and show that they can be given by Feynman diagrams on the spin-foams, where the Feynman propagators can be represented by a discretized path integral of a world-line action along the edges of the underlying 2-complex.

  3. Side branch morphology and coarsening in directionally solidified Pb-8.4 at. pct Au

    NASA Technical Reports Server (NTRS)

    Tewari, S. N.; Lee, David; Nesarikar, V. V.

    1989-01-01

    The scaling relationships among the morphological features associated with the formation of perturbations (side branches) in the intercellular regions of a directionally solidified Pg-8.4 at. pct Au alloy were investigated. It is shown that the ratio between the initial side-branch spacing near dendrite tips, lambda-2, and the dendrite-tip radius, r(t), equals 2 to 2.5. The ratio between the distance from the dendrite tip to the location of the first side branch formation, lambda(p), and the t(r) equals 8 to 10. It was found that the model proposed by Kirkwood (1985) for the secondary dendrite arm coarsening shows a very good quantitative fit to the experimentally observed secondary arm coarsening kinetics during directional solidification.

  4. Undercooling and solidification of Al-50 at. pct Si Alloy by electromagnetic levitation

    NASA Astrophysics Data System (ADS)

    Liu, R. P.; Herlach, D. M.; Vandyoussefi, M.; Greer, A. L.

    2004-02-01

    Electromagnetic levitation is applied to achieve containerless solidification of 10-mm-diameter droplets of Al-50 at. pct Si. A maximum undercooling of 320 K is obtained. Phase morphologies on the droplet surfaces and on the deeply etched sections of the samples solidified at different undercoolings are examined by scanning electron microscopy. The primary silicon shows well-developed faceted dendrites at a small undercooling, but a fine granular form at a large undercooling. Stratified deposits of aluminum are found within the primary silicon plates, arising from solute pileup during growth. The microstructural refinement at a large undercooling has its origins in solute restriction of crystal growth and in fragmentation of the primary silicon dendrites. The form of the Al-Si eutectic is also found to be changed into an anomalous form at a large undercooling.

  5. Synthesis of nanostructured WC-12 pct Co coating using mechanical milling and high velocity oxygen fuel thermal spraying

    SciTech Connect

    He, J. Ice, M.; Dallek, S.; Lavernia, E.J.

    2000-02-01

    A nanostructured WC-12 pct Co coating was synthesized using mechanical milling and high velocity oxygen fuel (HVOF) thermal spraying. The variation of powder characteristics with milling time and the performance of the coatings were investigated using scanning electron microscope (SEM), X-ray, transmission electron microscope (TEM), thermogravimetric analyzer (TGA), and microhardness measurements. There is no evidence that indicates the presence of an amorphous phase in the sintered WC-12 pct Co powder, and the binder phase in this powder is still crystalline Co. Mechanical milling of up to 20 hours did not lead to the formation of an amorphous phase in the sintered WC-12 pct Co powder. During the initial stages of the milling, the brittle carbide particles were first fractured into fragments and then embedded into the binder phase. This process gradually formed polycrystal nanocomposite powders of the Co binder phase and W carbide particles. The conventional cold welding and fracturing processes primarily occurred among the Co binder powders and polycrystal composite powders. The nanostructured WC-12 pct Co coatings, synthesized in the present study, consist of an amorphous matrix and carbides with an average particle diameter of 35 nm. The coating possesses an average microhardness of 1135 HV and higher resistance to indentation fracture than that of its conventional counterpart.

  6. Behavior of welds in liquid lead containing 10-6 wt% and 10-8 wt% oxygen

    NASA Astrophysics Data System (ADS)

    Heinzel, A.; Müller, G.; Weisenburger, A.

    2013-06-01

    Specimens with welded joints of P91 TIG (tungsten inert gas welding), P91 EB (electron beam welding) and frictions stir welding, with P92 (EB), PM2000 (EB) and combination of P91-PM2000 EB were tested 2000 h in stagnant liquid Pb at 550 °C with an oxygen concentration of 10-6 wt% and 10-8 wt%. After exposure at 10-6 wt% all specimens showed an oxide layer on the surface. If the grain size of the welds varies strongly from that of the bulk material like in the friction stir welds, a change in oxide thickness could be observed. Also precipitations which pin the oxide formers or reduce the diffusion rate can lead to thicker oxide layers or a stronger dissolution attack like it was observed on the dissimilar weld P91/PM2000 EB. The specimens have similar microstructures in all regions (weld, heat affected zone and bulk material) and due to a post-weld heat treatment show everywhere the same behavior.

  7. Effect of Friction Stir Processing on Fatigue Behavior of an Investment Cast Al-7Si-0.6 Mg Alloy

    SciTech Connect

    Jana, Saumyadeep; Mishra, Rajiv S.; Baumann, John B.; Grant, Glenn J.

    2010-02-01

    Cast aluminum alloys in general show poor fatigue performance due to presence of defects. Friction stir processing (FSP) can be used as a tool for enhancing mechanical properties of cast alloys by eliminating such defects. In the present study FSP led to a five times improvement in fatigue life of an investment cast Al-7Si-0.6Mg hypoeutectic alloy. The reason for such enhancement was linked to closure of casting porosity which acted as crack nucleation sites in the as-cast condition. Porosity acted as notches in the as-cast alloy and led to an order of magnitude higher crack growth rate. As FSP eliminated the porosity and refined Si particles, crack growth rate dropped due to the elimination of the notch effect together with increased crack path tortuosity. Finally, short crack behavior was noted in both cast and FSP specimens. The critical crack length where transition from short crack to long crack behavior took place is related to respective microstructural characteristic dimensions.

  8. Report on Characterization of U-10 wt.% Zr Alloy

    SciTech Connect

    McKeown, J; Wall, M; Hsiung, L; Turchi, P

    2012-03-01

    This report summarizes the chemical and structural characterization results for a U-10 wt.% Zr alloy to be used in an ultra-high burn-up nuclear fuel concept. The as-cast alloy material was received from Texas A and M University. Characterization and an initial heat treatment of the alloy material were conducted at Lawrence Livermore National Laboratory. The as-received ingot was sectioned for X-ray analysis, metallography, SEM, TEM, and heat treatments, as shown in Figure 1.

  9. Determination of PCT on admission is a useful tool for the assessment of disease severity in travelers with imported Plasmodium falciparum malaria.

    PubMed

    Righi, Elda; Merelli, Maria; Arzese, Alessandra; Siega, Paola Della; Scarparo, Claudio; Bassetti, Matteo

    2016-06-01

    Procalcitonin (PCT) and C-reactive protein (CRP) may be useful to predict complicated forms of malaria. A total of 30 consecutive travelers diagnosed with Plasmodium falciparum malaria over a two-year period were included in the study. Patients with complicated Plasmodium falciparum malaria showed higher levels of parasitemia (P = 0.0001), PCT (P = 0.0018), CRP (P = 0.0005), bilirubinemia (P = 0.004), and a lower platelet count (P<0.0001) compared with patients with uncomplicated forms. PCT levels above 5 ng/mL showed the highest value of specificity (0.86) and positive predictive factor (0.67) among other parameters, and equal sensitivity (0.67) was displayed by CRP levels above 150 mg/dl. None of the patients with complicated malaria showed PCT levels within normal limits (<0.5 ng/ml). Both PCT and CRP correlated with parasitemia (P<0.001) and showed areas under ROC curve of 0.83. At multivariate analysis, only PCT was associated with an increased risk of complicated malaria (OR 8.2, IC 95% 1.2-57.2, P = 0.03). The determination of PCT on admission showed better results compared to CRP, platelet count, and bilirubinemia and can be useful in non-endemic areas for the initial clinical assessment of disease severity in travelers with Plasmodium falciparum malaria. PMID:27078668

  10. Effect of a Transverse Magnetic Field on Solidification Structures in Unmodified and Sr-Modified Al-7wtpctSi Alloys During Directional Solidification

    NASA Astrophysics Data System (ADS)

    Li, Xi; Gagnoud, Annie; Fautrelle, Yves; Moreau, Rene; Du, Dafan; Ren, Zhongming; Lu, Xionggang

    2016-03-01

    The influence of a transverse magnetic field on the microstructures in unmodified and Sr-modified Al-7wtpctSi alloys during directional solidification was investigated. Experimental results indicated that the magnetic field caused the channel and freckle macrosegregations during directional solidification. Comparison of the microstructures in unmodified and Sr-modified Al-7wtpctSi alloys showed that the Sr-addition enhanced the convection effects. Moreover, the EBSD analysis revealed that the magnetic field changed the alignment of the α-Al dendrite and modified the distribution of dendrite fragments in both unmodified and Sr-modified Al-7wtpctSi alloys. Indeed, the application of the magnetic field caused the <001>-crystal direction of the α-Al dendrite to deflect from the solidification direction and induced the formation of dendrite fragments on one side of the sample. Further, the Seebeck signal ( E S) at the liquid/solid interface was measured in situ during directional solidification of Al-7wtpct Si alloy and the results indicated that the value of the E S was of the order of 10 μV and decreased with the increase of the growth speed. The above results may be attributed to the thermoelectric magnetic convection and its effect on the distribution of the solute Si. It is proven that solute effects are primarily responsible for dendrite fragmentation.

  11. The effect of APH treatment on surface bonding and osseointegration of Ti-6Al-7Nb implants: an in vitro and in vivo study.

    PubMed

    Nguyen, Thuy-Duong Thi; Moon, So-Hee; Oh, Tae-Ju; Park, Il-Song; Lee, Min-Ho; Bae, Tae-Sung

    2015-04-01

    This study investigated the effects of anodization-cyclic precalcification-heat (APH) treatment on the bonding ability of Ca-P coating to the parent metal and osseointegration of Ti-6Al-7Nb implants. Eighteen Ti-6Al-7Nb discs, 9 untreated and 9 APH-treated, were cultured with osteoblast cells in vitro, and the cellular differentiation ability was assayed at 1, 2, and 3 weeks. For in vivo testing, 28 Ti-6Al-7Nb implants (14 implants of each group) were inserted to rat tibias, and after each 4 and 6 weeks of implantation, bone bonding, and osseointegration were evaluated through removal torque and histological analysis. Osteoblast-culturing showed twice as much of the alkaline phosphatase activity on the treated surface at 3 weeks than on the untreated surface (p < 0.05). The treated implants exhibited higher removal torque values than the untreated ones (15.5 vs. 1.8 Ncm at 4 weeks and 19.7 vs. 2.6 Ncm at 6 weeks, p < 0.05). Moreover, the excellent bonding quality of coats was confirmed by the existence of cohesive fractures on the surface of removed APH implants (field emission scanning electron microscopy and histological observation). Within the limits of this study, it can be concluded that the APH treatment significantly enhanced osseointegration of the Ti-6Al-7Nb implant, with the stable bonding between the coating and the implant surface. PMID:24976109

  12. Effect of surface conditioning on the flowability of Ti6Al7Nb powder for selective laser melting applications

    NASA Astrophysics Data System (ADS)

    Marcu, T.; Todea, M.; Gligor, I.; Berce, P.; Popa, C.

    2012-01-01

    Porous metallic implants have been developed to provide a good implant-tissue mechanical attachment and an as close as possible elastic modulus to that of human bone, by the means of a proper porosity. A viable manufacturing technology for personalized implants is rapid prototyping (RP), which employs fine feeding powders which usually display a poor flow behaviour. In the present work, the required flowability of Ti6Al7Nb powder aimed for selective laser melting (SLM) applications was improved by applying a simple heat treatment in air, at temperatures higher than 500 °C. As flowability depends on the powder surface condition, the surface chemical composition before and after heat treatment was characterized by X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR) analysis. The results indicated that the amount of basic and acidic -OH groups is almost the same for powders treated at 400 °C, which do not flow, and powders treated at 500 °C, which display flowability. An increase of the Al2O3 amount in the TiO2-based surface layer on the powder particles with the treatment temperature was noticed. Based on the results, the temperature of 500 °C was selected for the further research. The conditioned powder displayed a very good technological behaviour, being successfully used for obtaining specimens with both cellular and fully dense structures through SLM. The microstructure of the manufactured samples, characterized by optical microscopy and scanning electron microscopy (SEM), has shown mainly α‧ martensite, with columnar grains.

  13. Activities of MnO in CaO-SiO2-Al2O3-MnO (<10 Pct)-FetO(<3 pct) slags saturated with liquid iron

    NASA Astrophysics Data System (ADS)

    Ohta, Hiroki; Suito, Hideaki

    1995-04-01

    Activity coefficients of MnO and Fe,0 in CaO-SiO2-Al2O3-MnO(<10 mass pct)-Fe,O(<3 mass pct) slags were determined at 1873 K in an Al2O3 or CaO crucible by using the reported values for the activities of Al2O3 and SiO2 or the analyzed contents of oxygen. The activity coefficients of MnO and FetO were found to be constant in the studied concentration range of MnO and FetO. The former increased with an increase in the CaO content, while the latter increased with an increase in the SiO2 content.

  14. In vivo behavior of surface modified Ti6Al7Nb alloys used in selective laser melting for custom-made implants. A preliminary study.

    PubMed

    Rotaru, H; Armencea, G; Spîrchez, Diana; Berce, C; Marcu, Teodora; Leordean, D; Kim, Seong Gon; Lee, Sang Woon; Dinu, C; Băciuţ, G; Băciuţ, Mihaela

    2013-01-01

    The objectives of this study were to test the biocompatibility and to evaluate the osseointegration of Titanium-Aluminum-Niobium (Ti6Al7Nb) alloy used in the manufacturing of personalized implants with selective laser melting (SLM) technology and to compare the growth viability of osteoblastic-like cells on different Ti6Al7Nb alloy samples (plain, coated with hydroxyapatite or SiO2-TiO2) implanted into the cranial bone of Wistar rats. In terms of biocompatibility, the cone-beam computer-tomography head scans taken at the moment of sacrifice of each group (one, two and three months) showed no implant displacement, no osteolysis and no liquid collection around the implants. At one month, around all types of implants new bone formation was noticed, although around the plain Ti6Al7Nb implant a large amount of powder debris was present. Still, no inflammatory reaction was seen. At two months, the distance between the implants and the calvarial bone margins diminished. A thin layer of fibrous tissue was noticed around the Ti6Al7Nb implant coated with hydroxyapatite but no bone contact was achieved. In the group sacrificed at three months there was still no bone contact, but noticeable were the SiO2-TiO2. In the group sacrificed at three months SiO2-TiO2 particles detached from the implant and completely integrated in the tissue were noticeable. All results suggested that the Ti6Al7Nb alloy with or without infiltration is well biologically tolerated. PMID:24322029

  15. Microsegregation in directionally solidified Pb-8.4 at. pct Au alloy

    NASA Technical Reports Server (NTRS)

    Tewari, S. N.

    1988-01-01

    The dependence of microsegregation behavior on growth rate and thermal gradient has been examined in a Pb-8.4 at. pct Au alloy material partially directionally solidified and quenched. The composition of the quenched 'liquid' at the dendrite tip (Ct), that of the eutectic-like solid phase freezing from the interdendritic liquid at the base of dendrite (Cse), the volume fraction of this eutectic-like region (fe), and solute profiles in the interdendritic quenched liquid and ahead of the dendrite have been measured. Two dendritic growth models for solidification of a binary alloy melt in a positive thermal gradient at the liquid-solid interface, one for dendrites with 'minimum undercooled dendrite tip' and the other for an Ivantsov type of dendrite with 'marginally stable tip', have been examined for a quantitative comparison with measured values of Ct, Cse, and fe. Convection in the melt, possibly due to horizontal density gradients, is found to be a serious limitation for theoretical understanding of the observed experimental behavior and meaningful comparison of theories.

  16. Interphase boundary precipitation in a Ti-1.7 at. pct Er alloy

    SciTech Connect

    Kral, M.V.; Hofmeister, W.H.; Wittig, J.E.

    1997-12-01

    Microstructures in a Ti-1.7 at. pct Er alloy were studied in the arc-cast, rapidly solidified, and annealed conditions. Transmission electron microscopy (TEM) of the rapidly solidified materials revealed 3- to 20-nm-diameter precipitates that were distributed in regularly spaced, approximately planar sheets throughout equiaxed {alpha} Ti grains. The precipitate sheet morphology is similar to the interphase boundary carbide sheets that have been documented in many alloy steels. In addition, precipitate fibers with cross sections of approximately 5 nm and up to 500 nm in length were often found adjacent to particle sheets. Electron diffraction experiments showed that the structure and lattice spacings of the sheet and fibrous particles are consistent with elemental erbium. Subsequent annealing treatments resulted in the formation of a face-centered cubic allotrope of Er{sub 2}O{sub 3}. The present work describes the precipitate morphologies and crystallography and discusses the applicability of current ledge growth models of interphase boundary precipitation to titanium-erbium alloys.

  17. TEM study of continuous precipitation in Mg-9 wt%Al-1 wt%Zn alloy[Transmission Electron Microscopy

    SciTech Connect

    Celotto, S.

    2000-05-11

    The development of continuous precipitate morphology in heat-treated Mg-9 wt%Al-1 wt%Zn alloy (AZ91) for a range of ageing temperatures is investigated in detail using TEM. The matrix/precipitate orientation relationships (ORs), sizes, shapes and the number of precipitates per unit volume (N{sub V}) are described for ageing at temperatures from 70 to 300 C. Most of the continuous precipitates have a Burgers OR and are plate-shaped with the primary habit plane parallel to the basal plane of the matrix. These precipitates are initially lozenge-shaped plates that elongate with time at temperature to become long laths. Two other smaller populations of precipitates that have ORs different from the Burgers OR are also present. These precipitates are rod-shaped with their long direction either perpendicular to or inclined to the basal plane. The relationship between the continuous precipitate morphology and the hardness response is discussed and comparisons are made with high-strength aluminum alloys.

  18. Analysis of the Plasticity-Enhancing Mechanisms in 12 pctMn Austeno-ferritic Steel by In Situ Neutron Diffraction

    NASA Astrophysics Data System (ADS)

    Lee, Sangwon; Woo, Wanchuck; De Cooman, Bruno C.

    2014-12-01

    The tensile behavior of ductile ultra-high strength Fe-12 pctMn-0.3 pctC-2 pctAl austeno-ferritic steel was studied by in situ neutron diffraction measurement of the elastic lattice strains, dislocation density, stacking fault probability, and strain-induced transformation kinetics. Micro-yielding was observed in austenite, and the plastic deformation of ferrite remained very limited throughout the deformation. The analysis identified three contributions to the strain hardening: twinning-induced plasticity, transformation-induced plasticity, and the accumulation of a high density of geometrically necessary dislocations accommodating the strain mismatch at the phase boundaries.

  19. Spinodal Decomposition and Ordering Transformation in U-6 wt% Nb

    SciTech Connect

    Hsiung, L M

    2005-08-15

    Phase stability and aging mechanisms in a water-quenched (WQ) U-6wt% Nb (WQ-U6Nb) alloy artificially aged at 200 C (16 hours) and naturally aged at room temperature for 15 years have been investigated. Age hardening/softening phenomenon is recorded from the artificially aged samples by microhardness measurement. The age hardening can be readily rationalized by the occurrence of spinodal decomposition (or fine-scaled Nb segregation), which results in the formation of a modulated structure in the aged samples. Prolonged aging leads to age softening of the alloy by coarsening of the modulated structure. Disorder-order or chemical ordering transformation is found within the naturally aged alloy according to TEM observations of antiphase domain boundaries (APBs) and superlattice diffraction patterns. The formation of a partially ordered phase in the naturally aged alloy is proposed and identified.

  20. Expanding cylinder experiments in Cu-2wt%Be

    NASA Astrophysics Data System (ADS)

    Stirk, Stewart; Winter, Ron

    2011-06-01

    Expanding cylinder techniques are useful methods of investigating dynamic fracture properties since uniform radial strains are achieved at high strain-rates. A gas-gun technique to achieve uniform radial expansion of a cylinder is explored in which the motion of the cylinder is driven by impact of a plastic projectile upon silastomer rubber that partially fills the specimen cylinder. Cylinders of age-hardened copper-beryllium alloy Cu-2wt%Be (TF00 treatment) have been expanded to failure at radial strain-rates in the range 1.2 - 5.7 ×103s-1. The temporal history of fracture activation is captured using high speed photography and modelled using a combined statistics and energy based fragmentation theory. The model is shown to reproduce the crack dynamics and strain-rate dependence reasonably well.

  1. Advanced solutions in combustion-based WtE technologies.

    PubMed

    Martin, Johannes J E; Koralewska, Ralf; Wohlleben, Andreas

    2015-03-01

    Thermal treatment of waste by means of combustion in grate-based systems has gained world-wide acceptance as the preferred method for sustainable management and safe disposal of residual waste. In order to maintain this position and to address new challenges and/or priorities, these systems need to be further developed with a view to energy conservation, resource and climate protection and a reduction in the environmental impact in general. MARTIN GmbH has investigated continuously how the implementation of innovative concepts in essential parts of its grate-based Waste-to-Energy (WtE) combustion technology can be used to meet the above-mentioned requirements. As a result of these efforts, new "advanced solutions" were developed, four examples of which are shown in this article. PMID:25305685

  2. A High-avidity WT1-reactive T-Cell Receptor Mediates Recognition of Peptide and Processed Antigen but not Naturally Occurring WT1-positive Tumor Cells.

    PubMed

    Jaigirdar, Adnan; Rosenberg, Steven A; Parkhurst, Maria

    2016-04-01

    Wilms tumor gene 1 (WT1) is an attractive target antigen for cancer immunotherapy because it is overexpressed in many hematologic malignancies and solid tumors but has limited, low-level expression in normal adult tissues. Multiple HLA class I and class II restricted epitopes have been identified in WT1, and multiple investigators are pursuing the treatment of cancer patients with WT1-based vaccines and adoptively transferred WT1-reactive T cells. Here we isolated an HLA-A*0201-restricted WT1-reactive T-cell receptor (TCR) by stimulating peripheral blood lymphocytes of healthy donors with the peptide WT1:126-134 in vitro. This TCR mediated peptide recognition down to a concentration of ∼0.1 ng/mL when pulsed onto T2 cells as well as recognition of HLA-A*0201 target cells transfected with full-length WT1 cDNA. However, it did not mediate consistent recognition of many HLA-A*0201 tumor cell lines or freshly isolated leukemia cells that endogeneously expressed WT1. We dissected this pattern of recognition further and observed that WT1:126-134 was more efficiently processed by immunoproteasomes compared with standard proteasomes. However, pretreatment of WT1 tumor cell lines with interferon gamma did not appreciably enhance recognition by our TCR. In addition, we highly overexpressed WT1 in several leukemia cell lines by electroporation with full-length WT1 cDNA. Some of these lines were still not recognized by our TCR suggesting possible antigen processing defects in some leukemias. These results suggest WT1:126-134 may not be a suitable target for T-cell based tumor immunotherapies. PMID:26938944

  3. The PanCam Calibration Target (PCT) and multispectral image processing for the ExoMars 2018 mission

    NASA Astrophysics Data System (ADS)

    Barnes, D.; Wilding, M.; Gunn, M.; Tyler, L.; Pugh, S.; Coates, A.; Griffiths, A.; Cousins, C.; Schmitz, N.; Paar, G.

    2011-10-01

    The Panoramic Camera (PanCam) instrument for the ESA/NASA 2018 ExoMars mission is designed to be the 'eyes' of the Mars rover and is equipped with two wide angle multispectral cameras (WACs) from MSSL, and a focusable High Resolution Camera (HRC) from DLR. To achieve its science role within the ExoMars mission, the PanCam will generate terrain reflectance spectra to help identify the mineralogy of the Martian surface, and generate true-colour images of the Martian environment. The PanCam Calibration Target (PCT) is an essential component for the science operations of the PanCam instrument. Its purpose is to allow radiometric calibration and to support geometric calibration check-out of the PanCam instrument during the mission. Unlike other camera calibration targets flown to Mars, the PCT target regions are being made from stained glass. The paper describes the work undertaken during the early build and testing of the PCT, together with results from the baseline algorithms that have been designed and implemented to process the multispectral PanCam images.

  4. Effect of Cold Rolling Reduction Rate on Secondary Recrystallized Texture in 3 Pct Si-Fe Steel

    NASA Astrophysics Data System (ADS)

    Imamura, Takeshi; Shingaki, Yukihiro; Hayakawa, Yasuyuki

    2013-04-01

    The phenomenon of secondary recrystallization in 3 pct Si-Fe electrical steel subjected to relatively high cold rolling reduction rates has been investigated. The texture of the secondary recrystallized sample that has a cold rolling reduction rate of 97.2 pct consists mainly of {110}<112> component, which is quite different from the ideal Goss ({110}<001>) texture obtained after lower cold rolling reduction rates. The grain boundary character distribution (GBCD) analysis on the primary recrystallized sample with a cold rolling reduction rate of 97.2 pct indicates that the {110}<112> component has the highest frequency of high energy (HE) boundary with a misorientation angle between 20 and 45 deg, whereas the Goss component in the sample subjected to lower cold rolling reduction rates has the highest frequency of HE boundary. These results indicate that the component with the highest frequency of HE boundary surrounding it after primary recrystallization has the privilege to outgrow other components during secondary recrystallization. However, the GBCD analysis for coincidence site lattice (CSL) boundary points out that the Goss component has the highest frequency of CSL boundaries in the primary recrystallized texture irrespective of the cold rolling reduction applied. These results suggest that the HE model can predict the orientation relationship between the primary and secondary recrystallized textures better than the CSL model.

  5. X-ray diffraction line profile analysis for defect study in Cu-1 wt.% Cr-0.1 wt.% Zr alloy

    SciTech Connect

    Kapoor, K. . E-mail: kapoork@nfc.ernet.in; Lahiri, D.; Batra, I.S.; Rao, S.V.R.; Sanyal, T.

    2005-02-15

    X-ray line profile analysis (LPA) has been used for microstructural analysis of a Cu-1 wt.% Cr-0.1 wt.% Zr alloy. Using this technique, the stacking fault probability (SFP) and stacking fault energy (SFE) has been determined for the pure Cu and the Cu-1 wt.% Cr-0.1 wt.% Zr alloy. It is observed that there is an increase in the stacking fault probability (and corresponding decrease in stacking fault energy) in case of the alloy. The increased formation of faulted regions in the Cu-1 wt.% Cr-0.1 wt.% Zr alloy is supported by the observation of extended dislocation nodes and fringe contrast due to staking faults under TEM, and higher work hardening rate in the tension test. The high thermal fatigue resistance of this alloy is attributed to decrease in the stacking fault energy by addition of Cr and Zr to Cu.

  6. Mutation or loss of Wilms' tumor gene 1 (WT1) are not major reasons for immune escape in patients with AML receiving WT1 peptide vaccination

    PubMed Central

    2010-01-01

    Background Efficacy of cancer vaccines may be limited due to immune escape mechanisms like loss or mutation of target antigens. Here, we analyzed 10 HLA-A2 positive patients with acute myeloid leukemia (AML) for loss or mutations of the WT1 epitope or epitope flanking sequences that may abolish proper T cell recognition or epitope presentation. Methods All patients had been enrolled in a WT1 peptide phase II vaccination trial (NCT00153582) and ultimately progressed despite induction of a WT1 specific T cell response. Blood and bone marrow samples prior to vaccination and during progression were analyzed for mRNA expression level of WT1. Base exchanges within the epitope sequence or flanking regions (10 amino acids N- and C-terminal of the epitope) were assessed with melting point analysis and sequencing. HLA class I expression and WT1 protein expression was analyzed by flow cytometry. Results Only in one patient, downregulation of WT1 mRNA by 1 log and loss of WT1 detection on protein level at time of disease progression was observed. No mutation leading to a base exchange within the epitope sequence or epitope flanking sequences could be detected in any patient. Further, no loss of HLA class I expression on leukemic blasts was observed. Conclusion Defects in antigen presentation caused by loss or mutation of WT1 or downregulation of HLA molecules are not the major basis for escape from the immune response induced by WT1 peptide vaccination. PMID:20092642

  7. Reoxidation of Aluminum in Fe- Al- M (M = C, Mn, and Ti) melts with CaO-Al2 O3-Fe t O (3 mass pct) slags

    NASA Astrophysics Data System (ADS)

    Lee, Kwang Ro; Suito, Hideaki

    1996-06-01

    An Fe-0.01 to 0.5 mass pct Al alloy and an Fe-0.003 to 0.71 mass pct Al-1 mass pct M (M = C, Mn, and Ti) alloy were reoxidized with the CaO-Al2O3-FetO (3 mass pct) slags at 1873 K in an Al2O3 or CaO crucible for 5 and 60 minutes. The contents of acid-insoluble Al, total O, and alloying element M in metal as well as those of M and FetO in slag were measured as a function of total Al content. On the basis of the present and previous results for Fe- Al- Te alloys, the effect of alloying elements on the degree of supersaturation with respect to the Al2O3 precipitation was studied. As a result, the supersaturation phenomenon was observed in all experiments at 5 minutes, but in the experiments at 60 minutes, it was observed only in Fe- Al and Fe- Al- Ti alloys. No supersaturation was observed in the reoxidation of Si in Fe-0.13 to 0.98 mass pct Si alloys with the CaO-SiO2-FetO (3 mass pct) slags in a CaO crucible at 5 and 60 minutes.

  8. Low-Temperature Agining Behavior of U-6 wt% Nb

    SciTech Connect

    Hsiung, L L

    2005-01-26

    Phase stability and aging mechanisms in a water-quenched (WQ) U-6wt% Nb (U-14at% Nb) alloy artificially aged at 200 C and naturally aged at ambient temperature for 15 years have been investigated and studied using Vickers-hardness measurement, X-ray diffraction (XRD) analysis, and transmission electron microscopy (TEM) techniques. Age hardening/softening phenomenon is recorded from the artificially aged samples based upon the microhardness measurement. The age hardening can be readily rationalized by the occurrence of fine-scaled Nb segregation, or spinodal decomposition, within the {alpha}'' domains, which results in the formation of a modulated structure containing nano-scaled Nb-rich and Nb-lean domains. Prolonged aging leads to age softening of the alloy by coarsening of the modulated structure. Chemical ordering, or disorder-order phase transformation, is found within the naturally aged alloy according to TEM observations of antiphase domain boundaries (APBs) and superlattice diffraction patterns. A possible superlattice structure for the ordered {alpha}'' phase observed in the naturally aged sample and underlying low-temperature aging mechanisms are proposed.

  9. Low-Temperature Aging Mechanisms in U-6wt% Nb

    SciTech Connect

    Hsiung, L L

    2004-12-07

    Phase stability and aging mechanisms in a water-quenched (WQ) U-6wt% Nb (U-14at% Nb) alloy artificially aged at 200 C and naturally aged at ambient temperature for 15 years have been investigated and studied using Vickers-hardness measurement, X-ray diffraction (XRD) analysis, and transmission electron microscopy (TEM) techniques. Age hardening/softening phenomenon is recorded from the artificially aged samples based upon the microhardness measurement. The age hardening can be readily rationalized by the occurrence of fine-scaled Nb segregation, or spinodal decomposition, within the {alpha}'' domains, which results in the formation of a modulated structure containing nano-scaled Nb-rich and Nb-lean domains. Prolonged aging leads to age softening of the alloy by coarsening of the modulated structure. Chemical ordering, or disorder-order phase transformation, is found within the naturally aged alloy according to TEM observations of antiphase domain boundaries (APBs) and superlattice diffraction patterns. A possible superlattice structure for the ordered {alpha}'' phase observed in the naturally aged sample and underlying low-temperature aging mechanisms are proposed.

  10. Mechanical properties of ion-implanted tungsten-5 wt% tantalum

    NASA Astrophysics Data System (ADS)

    Armstrong, D. E. J.; Wilkinson, A. J.; Roberts, S. G.

    2011-12-01

    Ion implantation has been used to simulate neutron damage in W-5wt%Ta alloy manufactured by arc melting. Implantations were carried out at damage levels of 0.07, 1.2, 13 and 33 displacements per atom (dpa). The mechanical properties of the ion-implanted layer were investigated by nanoindentation. The hardness increases rapidly from 7.3 GPa in the unimplanted condition to 8.8 GPa at 0.07 dpa. Above this damage level, the increase in hardness is lower, and the hardness change saturates by 13 dpa. In the initial portion of the load-displacement curves, the indentations in unimplanted material show a large 'initial pop-in' corresponding to the onset of plasticity. This is not seen in the implanted samples at any doses. The change in plasticity has also been studied using the nanoindenter in scanning mode to produce a topographical scan around indentations. In the unimplanted condition there is an extensive pile-up around the indentation. At damage levels of 0.07 and 1.2 dpa the extent and height of pile-up are much less. The reasons for this are under further investigation.

  11. Adiabatic calorimetric decomposition studies of 50 wt.% hydroxylamine/water.

    PubMed

    Cisneros, L O; Rogers, W J; Mannan, M S

    2001-03-19

    Calorimetric data can provide a basis for determining potential hazards in reactions, storage, and transportation of process chemicals. This work provides calorimetric data for the thermal decomposition behavior in air of 50wt.% hydroxylamine/water (HA), both with and without added stabilizers, which was measured in closed cells with an automatic pressure tracking adiabatic calorimeter (APTAC). Among the data provided are onset temperatures, reaction order, activation energies, pressures of noncondensable products, thermal stability at 100 degrees C, and the effect of HA storage time. Discussed also are the catalytic effects of carbon steel, stainless steel, stainless steel with silica coating, inconel, titanium, and titanium with silica coating on the reaction self-heat rates and onset temperatures. In borosilicate glass cells, HA was relatively stable at temperatures up to 133 degrees C, where the HA decomposition self-heat rate reached 0.05 degrees C/min. The added stabilizers appeared to reduce HA decomposition rates in glass cells and at ambient temperatures. The tested metals and metal surfaces coated with silica acted as catalysts to lower the onset temperatures and increase the self-heat rates. PMID:11165058

  12. Veneering technique for a Ti-6Al-7Nb framework used in a resin-bonded fixed partial denture with a highly filled indirect composite.

    PubMed

    Matsumura, Hideo; Yoneyama, Takayuki; Shimoe, Saiji

    2002-12-01

    This article presents a veneering technique for fixed partial denture frameworks made from a Ti-6Al-7Nb alloy. The fixed partial denture framework was prepared with a magnesia-based mold material and a centrifugal casting machine. An esthetic veneer was fabricated with a highly filled dual-polymerized composite material and a metal-conditioning agent. This technique can be applied as a standardized veneering procedure for the titanium alloy, for which porcelain fusing is currently difficult. PMID:12488858

  13. DNA-binding dependent and independent functions of WT1 protein during human hematopoiesis

    SciTech Connect

    Svensson, Emelie; Eriksson, Helena; Gekas, Christos; Olofsson, Tor; Richter, Johan; Gullberg, Urban . E-mail: urban.gullberg@hematologi.lu.se

    2005-08-01

    The Wilms tumor gene 1 (WT1) encodes a zinc-finger-containing transcription factor highly expressed in immature hematopoietic progenitor cells. Overexpression and presence of somatic mutations in acute leukemia indicate a role for WT1 in the pathogenesis of leukemia. CD34{sup +} progenitor cells were transduced with one splice variant of human WT1 without the KTS insert in the zinc-finger domain, WT1(+/-), and with a deleted mutant of WT1 lacking the entire zinc-finger region, WT1(delZ), thus incapable of binding DNA. We show that inhibition of erythroid colony formation and differentiation is absolutely dependent on the DNA-binding zinc-finger domain of WT1. Unexpectedly, however, WT1(delZ) was equally effective as wild type protein in the reduction of myeloid clonogenic growth as well as in stimulation of myeloid differentiation, as judged by the expression of cell surface CD11b. Expression of neither WT1(+/-) nor WT1(delZ) upregulated mRNA for the cdk inhibitor p21{sup Waf1/Cip1} or p27{sup Kip1}. Our results demonstrate that WT1 affects proliferation and differentiation in erythroid and myeloid cells by different molecular mechanisms, and suggest that mutations affecting the zinc-finger domain of WT1 could interfere with normal differentiation in the pathogenesis of leukemia.

  14. DNA recognition by splicing variants of the Wilms' tumor suppressor, WT1.

    PubMed Central

    Drummond, I A; Rupprecht, H D; Rohwer-Nutter, P; Lopez-Guisa, J M; Madden, S L; Rauscher, F J; Sukhatme, V P

    1994-01-01

    The Wilms' tumor suppressor, WT1, is a zinc finger transcriptional regulator which exists as multiple forms owing to alternative mRNA splicing. The most abundant splicing variants contain a nine-nucleotide insertion encoding lysine, threonine, and serine (KTS) in the H-C link region between the third and fourth WT1 zinc fingers which disrupts binding to a previously defined WT1-EGR1 binding site. We have identified WT1[+KTS] binding sites in the insulin-like growth factor II gene and show that WT1[+KTS] represses transcription from the insulin-like growth factor II P3 promoter. The highest affinity WT1[+KTS] DNA binding sites included nucleotide contacts involving all four WT1 zinc fingers. We also found that different subsets of three WT1 zinc fingers could bind to distinct DNA recognition elements. A tumor-associated, WT1 finger 3 deletion mutant was shown to bind to juxtaposed nucleotide triplets for the remaining zinc fingers 1, 2, and 4. The characterization of novel WT1 DNA recognition elements adds a new level of complexity to the potential gene regulatory activity of WT1. The results also present the possibility that altered DNA recognition by the dominant WT1 zinc finger 3 deletion mutant may contribute to tumorigenesis. Images PMID:8196623

  15. Effect of structural evolution on mechanical properties of ZrO2 coated Ti-6Al-7Nb-biomedical application

    NASA Astrophysics Data System (ADS)

    Zalnezhad, E.

    2016-05-01

    Zirconia (ZrO2) nanotube arrays were fabricated by anodizing pure zirconium (Zr) coated Ti-6Al-7Nb in fluoride/glycerol electrolyte at a constant potential of 60 V for different times. Zr was deposited atop Ti-6Al-7Nb via a physical vapor deposition magnetron sputtering (PVDMS) technique. Structural investigations of coating were performed utilizing X-ray diffraction (XRD) analysis. Field emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM) were used to characterize the morphology and microstructure of coatings. Unannealed ZrO2 nanotube arrays were amorphous. Monoclinic and tetragonal ZrO2 appeared when the coated substrates were heat treated at 450 °C and 650 °C, while monoclinic ZrO2 was found at 850 °C and 900 °C. Mechanical properties, including nanohardness and modulus of elasticity, were evaluated at different annealing temperatures using a nanoindentation test. The nanoindentation results show that the nanohardness and modulus of elasticity for Ti-6AL-7Nb increased by annealing ZrO2 coated substrate at 450 °C. The nanohardness and modulus of elasticity for coated substrate decreased with annealing temperatures of 650, 850, and 900 °C. At an annealing temperature of 900 °C, cracks in the ZrO2 thin film coating occurred. The highest nanohardness and elastic modulus values of 6.34 and 218 GPa were achieved at an annealing temperature of 450 °C.

  16. The chemical digestion of Ti6Al7Nb scaffolds produced by Selective Laser Melting reduces significantly ability of Pseudomonas aeruginosa to form biofilm.

    PubMed

    Junka, Adam F; Szymczyk, Patrycja; Secewicz, Anna; Pawlak, Andrzej; Smutnicka, Danuta; Ziółkowski, Grzegorz; Bartoszewicz, Marzenna; Chlebus, Edward

    2016-01-01

    In our previous work we reported the impact of hydrofluoric and nitric acid used for chemical polishing of Ti-6Al-7Nb scaffolds on decrease of the number of Staphylococcus aureus biofilm forming cells. Herein, we tested impact of the aforementioned substances on biofilm of Gram-negative microorganism, Pseudomonas aeruginosa, dangerous pathogen responsible for plethora of implant-related infections. The Ti-6Al-7Nb scaffolds were manufactured using Selective Laser Melting method. Scaffolds were subjected to chemical polishing using a mixture of nitric acid and fluoride or left intact (control group). Pseudomonal biofilm was allowed to form on scaffolds for 24 hours and was removed by mechanical vortex shaking. The number of pseudomonal cells was estimated by means of quantitative culture and Scanning Electron Microscopy. The presence of nitric acid and fluoride on scaffold surfaces was assessed by means of IR and rentgen spetorscopy. Quantitative data were analysed using the Mann-Whitney test (P ≤ 0.05). Our results indicate that application of chemical polishing correlates with significant drop of biofilm-forming pseudomonal cells on the manufactured Ti-6Al-7Nb scaffolds ( p = 0.0133, Mann-Whitney test) compared to the number of biofilm-forming cells on non-polished scaffolds. As X-ray photoelectron spectroscopy revealed the presence of fluoride and nitrogen on the surface of scaffold, we speculate that drop of biofilm forming cells may be caused by biofilm-supressing activity of these two elements. PMID:27150429

  17. Spinodal Ordering and Precipitation in U-6 wt% Nb

    SciTech Connect

    Hsiung, L; Zhou, J

    2005-12-19

    A combinative approach of microhardness testing, tensile testing, and TEM microstructural analysis was employed to study the microstructure and mechanical instability of a water-quenched U-6wt.% Nb (WQU6Nb) alloy subjected to different aging schedules including artificial aging at 200 C, 15-year natural aging at ambient temperatures, and 15-year natural aging followed by accelerative aging at 200 C. The changes in mechanical property during and after the aging processes were examined using microhardness and tensile-testing methods. During the early stages of artificial aging at 200 C, the microhardness of WQ-U6Nb alloy increased, i.e., age hardening, as a result of the development of nanoscale modulation caused by spinodal decomposition. Coarsening of the modulated structure occurred after a prolonged aging at 200 C for 16 hours, and it led to a decrease of microhardness, i.e., age softening. Phase instability was also found to occur in WQ-U6Nb alloy that was subjected to a 15-year natural aging at ambient temperatures. The formation of partially ordered domains resulting from a spinodal modulation with an atomic-scale wavelength rendered the appearance of swirl-shape antiphase domain boundaries (APBs) observed in TEM images. Although it did not cause a significant change in microhardness, 15-year natural aging has dramatically affected the aging mechanisms of the alloy isothermally aged at 200 C. Microhardness values of the NA alloy continuously increased after isothermal aging at 200 C for 96 hours as a result of the phase decomposition of partially ordered domains into Nb-depleted {alpha} phase and Nb-enriched U{sub 3}Nb ordered phase in the alloy. It is concluded that the long-term natural aging changes the transformation pathway of WQ-U6Nb, and it leads to order-disorder transformation and precipitation hardening of WQ-U6Nb alloy.

  18. Intercontinental Bistatic Radar Test Observation of Asteroid 1998 WT24

    NASA Technical Reports Server (NTRS)

    Righini, S.; Poppi, S.; Montebugnoli, S.; DiMartino, M.; Saba, L.; Delbo, M.; Ostro, S.; Monari, J.; Poloni, M.; Orlati, A.

    2002-01-01

    We describe the first intercontinental planetary radar test performed in Italy observing the near Earth asteroid (NEA) 33342 (1998 WT24) in December 2001 by means of the bistatic configurations Goldstone (California, USA)-Medicina (Italy) and Evpatoria (Ukraine)-Medicina. The experiment goal was to characterize the system for realtime radar follow-up observations of NEAs and artificial orbiting debris, in the framework of a feasibility study which aims at using the Sardinia Radio Telescope, at present under construction, also as a planetary radar facility. We report the preliminary results of the radar observations carried out by the IRA-CNR (Instituto di Radioastronomia - Consiglio Nazionale delle Ricerche) and the OATo (Osservatorio Astronomico di Torino) groups, aimed at exploring the scientific potentials of a new space radar program, using the existing facilities in Italy. The planetary radar technique is uniquely capable of investigating geometry and surface properties of various solar system objects, demonstrating advantages over the optical methods in its high spatial resolution and ability to obtain three-dimensional images. A single radar detection allows to obtain extremely accurate orbital elements, improving the instantaneous positional uncertainties by orders of magnitude with respect to an optically determined orbit. Radar is a powerful means to spatially resolve NEAs by measuring the distribution of the echo power in time delay (range) and Doppler frequency (line-of-sight velocity) with extreme precision in each coordinate, as it provides detailed information about the target physical properties like size, shape, rotation, near-surface bulk density and roughness and internal density distribution. The Medicina 32m antenna had been successfully used for the first time as the receiving part of a bistatic configuration during a test experiment (September 2001) held to check the capabilities of the entire data acquisition system. This test was possible

  19. Creep Behavior and Degradation of Subgrain Structures Pinned by Nanoscale Precipitates in Strength-Enhanced 5 to 12 Pct Cr Ferritic Steels

    NASA Astrophysics Data System (ADS)

    Ghassemi Armaki, Hassan; Chen, Ruiping; Maruyama, Kouichi; Igarashi, Masaaki

    2011-10-01

    Creep behavior and degradation of subgrain structures and precipitates of Gr. 122 type xCr-2W-0.4Mo-1Cu-VNb ( x = 5, 7, 9, 10.5, and 12 pct) steels were evaluated during short-term and long-term static aging and creep with regard to the Cr content of steel. Creep rupture life increased from 5 to 12 pct Cr in the short-term creep region, whereas in the long-term creep region, it increased up to 9 pct Cr and then decreased with the addition of Cr from 9 to 12 pct. Behavior of creep rupture life was attributed to the size of elongated subgrains. In the short-term creep region, subgrain size decreased from 5 to 12 pct Cr, corresponding to the longer creep strength. However, in the long-term creep region after 104 hours, subgrain size increased up to 9 pct Cr and then decreased from 9 to 12 pct, corresponding to the behavior of creep rupture life. M23C6 and MX precipitates had the highest number fraction among all of the precipitates present in the studied steels. Cr concentration dependence of spacing of M23C6 and MX precipitates exhibited a V-like shape during short-term as well as long-term aging at 923 K (650 °C), and the minimum spacing of precipitates belonged to 9 pct Cr steel, corresponding to the lowest recovery speed of subgrain structures. In the short-term creep region, subgrain coarsening during creep was controlled by strain and proceeded slower with the addition of Cr, whereas in long-term creep region, subgrain coarsening was controlled by the stability of precipitates rather than due to the creep plastic deformation and took place faster from 9 to 12 pct and 9 to 5 pct Cr. However, M23C6 precipitates played a more important role than MX precipitates in the control of subgrain coarsening, and there was a closer correlation between spacing of M23C6 precipitates and subgrain size during static aging and long-term creep region.

  20. Discordant phenotypes in monozygotic twins with identical de novo WT1 mutation.

    PubMed

    Yu, Zihua; Yang, Yonghui; Feng, Dongning

    2012-06-01

    Mutations in the WT1 gene, leading to Denys-Drash syndrome and Frasier syndrome, can also cause isolated steroid-resistant nephrotic syndrome (ISRNS). Previous studies have reported six pairs of monozygotic twins with WT1 mutations, including one presenting with discordant phenotypes with identical WT1 mutations being of paternal origin and five pairs of monozygotic twins presenting the same phenotype with identical WT1 mutations. In this study, we report on female monozygotic twins showing discordant phenotypes with an identical de novo WT1 mutation, R394W, and presenting incomplete Denys-Drash syndrome and ISRNS. PMID:26069768

  1. Peripheral Blood WT1 Expression Predicts Relapse in AML Patients Undergoing Allogeneic Stem Cell Transplantation

    PubMed Central

    Malagola, Michele; Skert, Cristina; Ruggeri, Giuseppina; Ribolla, Rossella; Bernardi, Simona; Borlenghi, Erika; Pagani, Chiara; Rossi, Giuseppe; Caimi, Luigi; Russo, Domenico

    2014-01-01

    To evaluate if WT1 expression may predict relapse after allo-SCT, we analyzed WT1 levels on peripheral blood (PB) and bone marrow (BM) before and after allo-SCT in 24 AML patients with WT1 overexpression at diagnosis. Five copies of WT1/ABL × 104 from PB were identified as the threshold value that correlated with relapse after allo-SCT. The same correlation was not identified when WT1 expression was assessed from bone marrow (BM). Eight out of 11 (73%) patients with a pre-allo-SCT PB-WT1 ≥ 5 and 4/13 (31%) patients with a pre-allo-SCT PB-WT1 < 5 relapsed, respectively (P = 0.04). The incidence of relapse was higher in patients with PB-WT1 ≥ 5 measured after allo-SCT, at the 3rd (56% versus 38%; P = 0.43) and at the 6th month (71% versus 20%; P = 0.03). Patients with pretransplant PB-WT1 < 5 had significantly better 2-year OS and LFS than patients with a PB-WT1 ≥ 5 (81% versus 0% and 63% versus 20%) (P = 0.02). Our data suggest the usefulness of WT1 monitoring from PB to predict the relapse in allotransplanted AML patients and to modulate the intensity of conditioning and/or the posttransplant immunosuppression in an attempt to reduce the posttransplant relapse risk. PMID:25202702

  2. Overlapping RNA and DNA binding domains of the wt1 tumor suppressor gene product.

    PubMed Central

    Bardeesy, N; Pelletier, J

    1998-01-01

    The Wilms' tumour suppressor gene (wt1) is mutated in a subset of patients with Wilms' tumour and has a critical role in urogenital development. wt1 encodes a zinc finger transcription factor which regulates expression of several genes involved in cellular proliferation and differentiation. Although a number of studies have characterized the DNA binding properties of the WT1 protein, recent evidence has suggested that WT1 may also have a role in RNA metabolism. We have used an RNA selection method to identify WT1 binding ligands from a random RNA pool. Three groups of RNA ligands specifically recognized by WT1 were identified. Mutational analysis pinpointed ribonucleotide sequences critical for binding. Analysis of truncated WT1 proteins demonstrated that three of four zinc fingers were necessary for RNA-protein interaction. The naturally occurring WT1 isoforms with insertion of lysine, threonine and serine between zinc fingers three and four were unable to bind the selected RNAs. The selected RNA ligands competed with the cognate WT1 DNA binding site for complex formation with WT1. Our findings suggest potential cellular RNA target sequences for WT1 and provide tools for studying the structural and functional properties of this tumour suppressor protein. PMID:9512553

  3. Cooling induced segregation of impurity elements to grain boundaries in Fe-3wt%Ni alloys, 2[1/4]wt%Cr-1wt%Mo steel and submerged arc weld metal

    SciTech Connect

    Vorlicek, V.; Flewitt, P.E.J. . Technology Div.)

    1994-10-01

    Previous theoretical and experimental studies demonstrate that small bulk concentrations of impurity and solute elements can segregate to grain boundaries in ferritic steels during cooling from high temperatures. This results from solute-vacancy pair formation and their subsequent diffusion to the grain boundary sinks. The grain boundary segregation which results from cooling at three different rates from fixed temperatures of 1,273 and 1,323 K respectively, have been measured on ferritic Fe-3 wt%Ni alloys and 2[1/4]wt%Cr-1wt%Mo steels containing additions of either P or Sn. In addition, a C-Mn submerged arc weld metal subject to a complex thermal cycle has been investigated. The composition of the grain boundaries have been measured on thin foil specimens using both conventional and high resolution STEM-EDS X-ray microanalysis techniques. Segregations of both P and Sn have been observed in the Fe-3 wt%Ni alloys and 2[1/4]wt%Cr-1wt%Mo steels and P segregations in the weld metal. The measured grain boundary segregations of both P and Sn are discussed with respect to previous theoretical predictions for the cooling rates investigated and the interactive role of other elements present.

  4. Lithium ion batteries made of electrodes with 99 wt% active materials and 1 wt% carbon nanotubes without binder or metal foils

    NASA Astrophysics Data System (ADS)

    Hasegawa, Kei; Noda, Suguru

    2016-07-01

    Herein, we propose lithium ion batteries (LIBs) without binder or metal foils, based on a three-dimensional carbon nanotube (CNT) current collector. Because metal foils occupy 20-30 wt% of conventional LIBs and the polymer binder has no electrical conductivity, replacing such non-capacitive materials is a valid approach for improving the energy and power density of LIBs. Adding only 1 wt% of few-wall CNTs to the active material enables flexible freestanding sheets to be fabricated by simple dispersion and filtration processes. Coin cell tests are conducted on full cells fabricated from a 99 wt% LiCoO2-1 wt% CNT cathode and 99 wt% graphite-1 wt% CNT anode. Discharge capacities of 353 and 306 mAh ggraphite-1 are obtained at charge-discharge rates of 37.2 and 372 mA ggraphite-1, respectively, with a capacity retention of 65% at the 500th cycle. The suitability of the 1 wt% CNT-based composite electrodes for practical scale devices is demonstrated with laminate cells containing 50 × 50 mm2 electrodes. Use of metal combs instead of metal foils enables charge-discharge operation of the laminate cell without considerable IR drop. Such electrodes will minimize the amount of metal and maximize the amount of active materials contained in LIBs.

  5. An investigation of the thermal cycling damage of 25 vol. pct SiCw/alumina ceramic matrix composite

    NASA Technical Reports Server (NTRS)

    Armstrong, William D.; Taya, Minoru

    1989-01-01

    An investigation was made of the thermal cycling damage of a 25 vol pct SiC whisker/alumina (SiCw/Al2O3) composite. Thermal cycling tests were conducted by subjecting a composite specimen to two different fluidized beds. After thermal cycling the composite specimens were subjected to elastic modulus and effective fracture toughness measurements. The thermal cycled specimens were investigated with SEM and TEM studies. It was found that this composite has a relatively high resistance to thermal cycling.

  6. Transformation to Ni5Al3 in a 63.0 at. pct Ni-Al alloy

    NASA Technical Reports Server (NTRS)

    Khadkikar, P. S.; Locci, I. E.; Vedula, K.; Michal, G. M.

    1993-01-01

    Microstructures of 63 at. pct P/M Ni-Al alloys with a composition close to the stoichiometry of the Ni5Al3 phase were investigated using homogenized and quenched specimens aged at low temperatures for various times. Results of analyses of XRD data and electron microscopy observations were used for quantitative phase analysis, performed to calculate the (NiAl + Ni5Al3)/Ni5Al3 phase boundary locations. The measured lattice parameters of Ni5Al3 phase formed at 823, 873, and 923 K indicated an increase in tetragonality of the phase with increasing nickel content.

  7. Lentivirus-Induced Dendritic Cells for Immunization Against High-Risk WT1+ Acute Myeloid Leukemia

    PubMed Central

    Sundarasetty, Bala Sai; Singh, Vijay Kumar; Salguero, Gustavo; Geffers, Robert; Rickmann, Mareike; Macke, Laura; Borchers, Sylvia; Figueiredo, Constanca; Schambach, Axel; Gullberg, Urban; Provasi, Elena; Bonini, Chiara; Ganser, Arnold; Woelfel, Thomas

    2013-01-01

    Abstract Wilms' tumor 1 antigen (WT1) is overexpressed in acute myeloid leukemia (AML), a high-risk neoplasm warranting development of novel immunotherapeutic approaches. Unfortunately, clinical immunotherapeutic use of WT1 peptides against AML has been inconclusive. With the rationale of stimulating multiantigenic responses against WT1, we genetically programmed long-lasting dendritic cells capable of producing and processing endogenous WT1 epitopes. A tricistronic lentiviral vector co-expressing a truncated form of WT1 (lacking the DNA-binding domain), granulocyte-macrophage colony-stimulating factor (GM-CSF), and interleukin-4 (IL-4) was used to transduce human monocytes ex vivo. Overnight transduction induced self-differentiation of monocytes into immunophenotypically stable “SmartDC/tWT1” (GM-CSF+, IL-4+, tWT1+, IL-6+, IL-8+, TNF-α+, MCP-1+, HLA-DR+, CD86+, CCR2+, CCR5+) that were viable for 3 weeks in vitro. SmartDC/tWT1 were produced with peripheral blood mononuclear cells (PBMC) obtained from an FLT3-ITD+ AML patient and surplus material from a donor lymphocyte infusion (DLI) and used to expand CD8+ T cells in vitro. Expanded cytotoxic T lymphocytes (CTLs) showed antigen-specific reactivity against WT1 and against WT1+ leukemia cells. SmartDC/tWT1 injected s.c. into Nod.Rag1−/−.IL2rγc−/− mice were viable in vivo for more than three weeks. Migration of human T cells (huCTLs) to the immunization site was demonstrated following adoptive transfer of huCTLs into mice immunized with SmartDC/tWT1. Furthermore, SmartDC/tWT1 immunization plus adoptive transfer of T cells reactive against WT1 into mice resulted in growth arrest of a WT1+ tumor. Gene array analyses of SmartDC/tWT1 demonstrated upregulation of several genes related to innate immunity. Thus, SmartDC/tWT1 can be produced in a single day of ex vivo gene transfer, are highly viable in vivo, and have great potential for use as immunotherapy against malignant transformation overexpressing WT1

  8. Ubiquitin specific protease 18 (Usp18) is a WT1 transcriptional target

    PubMed Central

    Makki, Mohammad Shahidul; Ruteshouser, E. Cristy; Huff, Vicki

    2013-01-01

    Wilms tumor gene WT1 encodes a zinc finger containing transcription factor which is required for renal development. Mutations in WT1 are observed in 20% of Wilms tumor (a pediatric kidney cancer), but the in vivo WT1 targets and associated molecular pathways involved in the etiology of Wilms tumor are still elusive. To identify WT1 targets we performed genome wide comprehensive expression profiling using Affymetrix Gene Chip Mouse Genome 430 2.0 Array, comparing E13.5 mouse kidneys in which Wt1 had been somatically ablated with littermate controls. We identified Usp18 as the most differentially expressed gene in mutant kidney. Using tetracycline inducible cells we demonstrated a repressive effect of WT1 on USP18 expression. Conversely, knockdown of WT1 led to the upregulation of Usp18. Furthermore, direct binding of WT1 to the Usp18 promoter was demonstrated by ChIP assay. Overexpression of USP18 in murine and human cell lines resulted in cell proliferation. Additionally, Usp18 upregulation was observed in a mouse model of Wilms tumor. Taken together our data demonstrate that Usp18 is a transcriptional target of WT1 and suggest that increased expression of USP18 following WT1 loss contributes to Wilms tumorigenesis. PMID:23291318

  9. Fine structure analysis of the WT1 gene in sporadic Wilms tumors.

    PubMed Central

    Varanasi, R; Bardeesy, N; Ghahremani, M; Petruzzi, M J; Nowak, N; Adam, M A; Grundy, P; Shows, T B; Pelletier, J

    1994-01-01

    Molecular genetic studies indicate that the etiology of Wilms tumor (WT) is complex, involving at least three loci. Germ-line mutations in the tumor suppressor gene, WT1, have been documented in children with WTs and urogenital developmental anomalies. Sporadic tumors constitute the majority (> 90%) of WT cases and previous molecular analyses of the WT1 gene have focused only on the DNA-binding domain. Using the single-strand conformational polymorphism (SSCP) assay, we analyzed the structural integrity of the entire WT1 gene in 98 sporadic WTs. By PCR-SSCP we find that mutations in the WT1 gene are rare, occurring in only six tumors analyzed. In one sample, two independent intragenic mutations inactivated both WT1 alleles, providing a singular example of two different somatic alterations restricted to the WT1 gene. This case is consistent with the existence of only one tumor suppressor gene at 11p13 involved in the pathogenesis of WTs. Our data, together with the previously ascertained occurrence of large deletions/insertions in WT1, define the frequency at which the WT1 gene is altered in sporadic tumors. Images PMID:8170946

  10. The Role of WT1 in Embryonic Development and Normal Organ Homeostasis.

    PubMed

    Wilm, Bettina; Muñoz-Chapuli, Ramon

    2016-01-01

    The Wilms' tumor suppressor gene 1 (Wt1) is critically involved in a number of developmental processes in vertebrates, including cell differentiation, control of the epithelial/mesenchymal phenotype, proliferation, and apoptosis. Wt1 proteins act as transcriptional and post-transcriptional regulators, in mRNA splicing and in protein-protein interactions. Furthermore, Wt1 is involved in adult tissue homeostasis, kidney function, and cancer. For these reasons, Wt1 function has been extensively studied in a number of animal models to establish its spatiotemporal expression pattern and the developmental fate of the cells expressing this gene. In this chapter, we review the developmental anatomy of Wt1, collecting information about its dynamic expression in mesothelium, kidney, gonads, cardiovascular system, spleen, nervous system, lung, and liver. We also describe the adult expression of Wt1 in kidney podocytes, gonads, mesothelia, visceral adipose tissue, and a small fraction of bone marrow cells. We have reviewed the available animal models for Wt1-expressing cell lineage analysis, including direct Wt1 expression reporters and systems for permanent Wt1 lineage tracing, based on constitutive or inducible Cre recombinase expression under control of a Wt1 promoter. Finally we provide a number of laboratory protocols to be used with these animal models in order to assess reporter expression. PMID:27417957

  11. Effect of cooling after welding on microstructure and mechanical properties of 12 pct Cr steel weld metals

    SciTech Connect

    Cai, G.J.; Andren, H.O.; Svensson, L.E.

    1997-07-01

    The microstructure of three 12 pct Cr steel weld metals with different nickel and nitrogen contents was studied in as-welded condition and after postweld heat treatment with and without intercooling. Tensile strength and impact toughness of the weld metals were investigated in different postweld heat treatment conditions. In weld metals heat treated without intercooling, austenite decomposed by a eutectoid reaction that resulted in M{sub 23}C{sub 6} aggregates around retained {delta}-ferrite. Two morphologies of M{sub 2}N and MN precipitates were found in a low-dislocation {alpha}-ferrite. It was concluded that these phases were also transformed from austenite. In weld metals heat treated with intercooling, M{sub 23}C{sub 6} precipitates were smaller and more homogeneously distributed. Different MN precipitates were found in the tempered martensite. The fracture mode of the weld metals at room temperature was mainly transgranular cleavage with some fibrous fracture. Intercooling treatment improved Charpy impact toughness of the 12 pct Cr steel weld metals substantially. It was found that the important microstructural factors affecting the impact toughness of the weld metals which were heat treated without intercooling were the sizes of the {alpha}-ferrite grains, nonmetallic inclusions, and M{sub 23}C{sub 6} aggregates. For the weld metals heat treated with intercooling, the factors which affect the toughness of the weld metals were the sizes of martensite packets and nonmetallic inclusions.

  12. Mössbauer spectroscopic studies of Fe-20 wt.% Cr ball milled alloy

    NASA Astrophysics Data System (ADS)

    Pandey, Brajesh; Rao, M. Ananda; Verma, H. C.; Bhargava, S.

    2006-04-01

    Interesting differences were noticed in the alloying process during ball milling of Fe-10 wt.% Cr and Fe-20 wt.% Cr alloys by 57Fe Mössbauer spectroscopic studies. In both cases, there is almost no diffusion of Fe in Cr or vice versa up to 20 h of milling time. As the powders are milled for another 20 h substantive changes occur in the Mössbauer spectra showing atomic level mixing. But the two compositions behave differently with respect to alloying. Fe-20 wt.% Cr sample does not differ much in the hyperfine field distribution as it is milled from 40 to 100 h. On the other hand, the hyperfine field distribution keeps on changing with milling time for Fe-10 wt.% Cr sample even up to 100 h of milling. The average crystallite size is found to be 7.5 nm for Fe-10 wt.% Cr and 6.5 nm in Fe-20 wt.% Cr after milling.

  13. Mössbauer spectroscopic studies of Fe-20 wt.% Cr ball milled alloy

    NASA Astrophysics Data System (ADS)

    Pandey, Brajesh; Ananda Rao, M.; Verma, H. C.; Bhargava, S.

    Interesting differences were noticed in the alloying process during ball milling of Fe-10 wt.% Cr and Fe-20 wt.% Cr alloys by 57Fe Mössbauer spectroscopic studies. In both cases, there is almost no diffusion of Fein Cr or vice versa up to 20 h of milling time. As the powders are milled for another 20 h substantive changes occur in the Mössbauer spectra showing atomic level mixing. But the two. compositions behave differently with respect to alloying. Fe-20 wt.% Cr sample does not differ much in the hyperfine field distribution as it is milled from 40 to 100 h. On the other hand, the hyperfine field distribution keeps on changing with milling time for Fe-10 wt.% Cr sample even up to 100 h of milling. The average crystallite size is found to be 7.5 nm for Fe-10 wt.% Cr and 6.5 nm in Fe-20 wt.% Cr after milling.

  14. Effect of 0.3 wt.% Al Addition in Flowing Liquid Zinc on the Erosion-Corrosion Behavior of Fe-3.5 wt.% B Alloy

    NASA Astrophysics Data System (ADS)

    Wang, Yong; Xing, Jiandong; Ma, Shengqiang; Liu, Guangzhu; Fu, Hanguang; Jia, Sen

    2015-06-01

    The effects of 0.3 wt.% Al added to flowing liquid zinc on the corrosion inhibition and erosion-corrosion interfacial characteristics of Fe-3.5 wt.% B alloy were investigated in order to separate the pure erosion rate from the total erosion-corrosion rate and further study the erosion-corrosion interaction created by flowing zinc. The result indicated that the erosion-corrosion rate increased slowly and then sharply thereafter, while the corrosion-inhibition rate increased linearly and slowly at a bath temperature of 460-550 °C. The corrosion-inhibition efficiency of 0.3 wt.% Al addition in the flowing liquid zinc bath was significantly reduced and then enhanced with increasing bath temperatures, depending on the interfacial microstructures after Al-corrosion inhibition. A uniform and continuous Fe2Al5Zn x inhibition layer, which suppressed the corrosion reaction of iron and zinc, formed on the erosion-corrosion interface of the Fe-3.5 wt.% B alloy, thereby reducing the spallation of anticaustic Fe2B skeleton. Moreover, the gradual deterioration of the inhibition layer led to a reduction in the corrosion-inhibition ability. The present results indicate that, due to the beneficial Al-corrosion inhibition effect, the corrosion-inhibition rate as the pure erosion rate of Fe-3.5 wt.% B in flowing liquid zinc can be well separated from the erosion-corrosion rate by adding 0.3 wt.% Al to flowing liquid zinc bath.

  15. Analysis of aquifer tests conducted in boreholes USW WT-10, UE-25 WT No. 12, and USW SD-7, 1995-96, Yucca Mountain, Nevada

    SciTech Connect

    O`Brien, G.M.

    1997-09-01

    Single-borehole aquifer tests were conducted in three boreholes in the Yucca Mountain area between March 1995 and January 1996 to obtain estimates of borehole specific capacity and aquifer transmissivity. Analysis of aquifer testing in borehole USW SD-7 also resulted in an estimate of reservoir volume. Aquifer-test data were analyzed with the Cooper and Jacob straight-line method, two modified Theis nonequilibrium equation solutions, and a modified reservoir-limit solution. The highest estimates of transmissivity were in borehole USW WT-10, completed in the Topopah Spring Tuff. Mean transmissivity, based on the results of three drawdown tests, was 1,600 meters squared per day. Mean specific capacity in borehole USW WT-10 after 5 hours of pumping was 1,100 meters squared per day, and was estimated to be 740 meters squared per day after 24 hours of pumping. Aquifer testing in borehole UE-25 WT No. 12 appeared to be significantly affected by well losses. A mean transmissivity of 7 meters squared per day was obtained on the basis of analysis of three drawdown tests in borehole UE-25 WT No. 12. Mean specific capacity in borehole UE-25 WT No. 12, after 24 hours of pumping, was 7 meters squared per day. Borehole UE-25 WT No. 12 seemed to be producing water from fractures that could provide only a limited amount of water to the borehole.

  16. 45 CFR 260.32 - What does the term “WtW cash assistance” mean?

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 45 Public Welfare 2 2014-10-01 2012-10-01 true What does the term âWtW cash assistanceâ mean? 260... Program? § 260.32 What does the term “WtW cash assistance” mean? (a) For the purpose of § 264.1(b)(1)(iii) of this chapter, WtW cash assistance only includes benefits that: (1) Meet the definition...

  17. 45 CFR 260.32 - What does the term “WtW cash assistance” mean?

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 45 Public Welfare 2 2011-10-01 2011-10-01 false What does the term âWtW cash assistanceâ mean? 260... Program? § 260.32 What does the term “WtW cash assistance” mean? (a) For the purpose of § 264.1(b)(1)(iii) of this chapter, WtW cash assistance only includes benefits that: (1) Meet the definition...

  18. 45 CFR 260.32 - What does the term “WtW cash assistance” mean?

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 45 Public Welfare 2 2013-10-01 2012-10-01 true What does the term âWtW cash assistanceâ mean? 260... Program? § 260.32 What does the term “WtW cash assistance” mean? (a) For the purpose of § 264.1(b)(1)(iii) of this chapter, WtW cash assistance only includes benefits that: (1) Meet the definition...

  19. 45 CFR 260.32 - What does the term “WtW cash assistance” mean?

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 45 Public Welfare 2 2012-10-01 2012-10-01 false What does the term âWtW cash assistanceâ mean? 260... Program? § 260.32 What does the term “WtW cash assistance” mean? (a) For the purpose of § 264.1(b)(1)(iii) of this chapter, WtW cash assistance only includes benefits that: (1) Meet the definition...

  20. WT1 suppresses synthesis of the epidermal growth factor receptor and induces apoptosis.

    PubMed Central

    Englert, C; Hou, X; Maheswaran, S; Bennett, P; Ngwu, C; Re, G G; Garvin, A J; Rosner, M R; Haber, D A

    1995-01-01

    The Wilms tumor suppressor gene WT1 encodes a developmentally regulated transcription factor that is mutated in a subset of embryonal tumors. To test its functional properties, we developed osteosarcoma cell lines expressing WT1 under an inducible tetracycline-regulated promoter. Induction of WT1 resulted in programmed cell death. This effect, which was differentially mediated by the alternative splicing variants of WT1, was independent of p53. WT1-mediated apoptosis was associated with reduced synthesis of the epidermal growth factor receptor (EGFR), but not of other postulated WT1-target genes, and it was abrogated by constitutive expression of EGFR. WT1 repressed transcription from the EGFR promoter, binding to two TC-rich repeat sequences. In the developing kidney, EGFR expression in renal precursor cells declined with the onset of WT1 expression. Repression of EGFR and induction of apoptosis by mechanism that may contribute to its critical role in normal kidney development and to the immortalization of tumor cells with inactivated WT1 alleles. Images PMID:7588596

  1. Expression of the Wilms' tumor gene WT1 in the murine urogenital system.

    PubMed

    Pelletier, J; Schalling, M; Buckler, A J; Rogers, A; Haber, D A; Housman, D

    1991-08-01

    The Wilms' tumor gene WT1 is a recessive oncogene that encodes a putative transcription factor implicated in nephrogenesis during kidney development. In this report we analyze expression of WT1 in the murine urogenital system. WT1 is expressed in non-germ-cell components of the testis and ovaries in both young and adult mice. In situ mRNA hybridization studies demonstrate that WT1 is expressed in the granulosa and epithelial cells of ovaries, the Sertoli cells of the testis, and in the uterine wall. In addition to the 3.1-kb WT1 transcript detected by Northern blotting of RNA from kidney, uterus, and gonads, there is an approximately 2.5-kb WT1-related mRNA species in testis. The levels of WT1 mRNA in the gonads are among the highest observed, surpassing amounts detected in the embryonic kidney. During development, these levels are differentially regulated, depending on the sexual differentiation of the gonad. Expression of WT1 mRNA in the female reproductive system does not fluctuate significantly from days 4 to 40 postpartum. In contrast, WT1 mRNA levels in the tesis increase steadily after birth, reaching their highest expression levels at day 8 postpartum and decreasing slightly as the animal matures. Expression of WT1 in the gonads is detectable as early as 12.5 days postcoitum (p.c.). As an initial step toward exploring the tissue-specific expression of WT1, DNA elements upstream of WT1 were cloned and sequenced. Three putative transcription initiation sites, utilized in testis, ovaries, and uterus, were mapped by S1 nuclease protection assays. The sequences surrounding these sites have a high G + C content, and typical upstream CCAAT and TATAA boxes are not present. These studies allowed us to identify the translation initiation site for WT1 protein synthesis. We have also used an epitope-tagging protocol to demonstrate that WT1 is a nuclear protein, consistent with its role as a transcription factor. Our results demonstrate regulation of WT1 expression

  2. Nonlinear relationship between the Product Consistency Test (PCT) response and the Al/B ratio in a soda-lime aluminoborosilicate glass

    NASA Astrophysics Data System (ADS)

    Farooqi, Rahmat Ullah; Hrma, Pavel

    2016-06-01

    We have investigated the effect of Al/B ratio on the Product Consistency Test (PCT) response. In an aluminoborosilicate soda-lime glass based on a modified International Simple Glass, ISG-3, the Al/B ratio varied from 0 to 0.55 (in mole fractions). In agreement with various models of the PCT response as a function of glass composition, we observed a monotonic increase of B and Na releases with decreasing Al/B mole ratio, but only when the ratio was higher than 0.05. Below this value (Al/B < 0.05), we observed a sharp decrease that we attribute to B in tetrahedral coordination.

  3. Prognostic Impact of WT-1 Gene Expression in Egyptian Children with Acute Lymphoblastic Leukemia

    PubMed Central

    Hagag, Adel A; Badraia, Ibrahim M; Hassan, Samir M; Abd El-Lateef, Amal E

    2016-01-01

    Background Acute lymphoblastic leukemia (ALL) is the most common childhood cancer representing 23% of pediatric cancers. Wilms’ tumor -1 gene is a novel prognostic factor, minimal residual disease marker and therapeutic target in acute leukemia. Aim of the work The aim of this work was to study the impact of WT-1 gene expression in the prognosis of ALL. Patients and methods This study was conducted on 40 Egyptian children with newly diagnosed ALL who were subjected to full history taking, thorough clinical examination and laboratory investigations including; complete blood count, LDH, BM aspiration, cytochemistry, immunophenotyping, FISH technique for detection of t(12;21) and t(9;22) and assessment of WT-1 Gene by real-time PCR in BM samples at time of diagnosis. Results Positive WT-1 gene expression was found in 22 cases (55%) and negative expression in 18 cases (45%). Positive WT-1 gene expression group (n=22) includes 14 males and 8 females with mean age at presentation of 5.261 ± 0.811 while negative WT-1 gene expression group (n=18) includes 12 males and 6 females with mean age at diagnosis of 9.669 ± 3.731 with significantly older age in negative WT-1 gene expression group but no significant differences between positive and negative WT-1 gene expression groups regarding sex and clinical presentations. There were no significant differences in platelets and WBCs counts, hemoglobin and LDH levels and the number of peripheral blood and BM blast cells at diagnosis between positive and negative WT-1 gene expression groups but after induction therapy there were significantly lower BM blast cells in positive WT-1 gene expression group. There were no statistically significant differences between positive and negative WT-1 gene expression groups regarding immunophenotyping and chromosomal translocations including t(12;21) and t(9;22). There were a significantly higher relapse and death rate and a lower rate of CR, DFS, and OAS in negative WT-1 gene expression

  4. High affinity binding sites for the Wilms' tumour suppressor protein WT1.

    PubMed Central

    Hamilton, T B; Barilla, K C; Romaniuk, P J

    1995-01-01

    The Wilms' tumour suppressor protein (WT1) is a putative transcriptional regulatory protein with four zinc fingers, the last three of which have extensive sequence homology to the early growth response-1 (EGR-1) protein. Although a peptide encoding the zinc finger domain of WT1[-KTS] can bind to a consensus 9 bp EGR-1 binding site, current knowledge about the mechanisms of zinc finger-DNA interactions would predict a more extended recognition site for WT1. Using a WT1[-KTS] zinc finger peptide (WT1-ZFP) and the template oligonucleotide GCG-TGG-GCG-NNNNN in a binding site selection assay, we have determined that the highest affinity binding sites for WT1[-KTS] consist of a 12 bp sequence GCG-TGG-GCG-(T/G)(G/A/T)(T/G). The binding of WT1-ZFP to a number of the selected sequences was measured by a quantitative nitrocellulose filter binding assay, and the results demonstrated that these sequences have a 4-fold higher affinity for the protein than the nonselected sequence GCG-TGG-GCG-CCC. The full length WT1 protein regulates transcription of reporter genes linked to these high affinity sequences. A peptide lacking the first zinc finger of WT1[-KTS], but containing the three zinc fingers homologous to EGR-1 failed to select any specific sequences downstream of the GCG-TGG-GCG consensus sequence in the binding site selection assay. DNA sequences in the fetal promoter of the insulin-like growth factor II gene that confer WT1 responsiveness in a transient transfection assay bind to the WT1-ZFP with affinities that vary according to the number of consensus bases each sequence possesses in the finger 1 subsite. PMID:7862533

  5. Sequence and structural requirements for high-affinity DNA binding by the WT1 gene product.

    PubMed Central

    Nakagama, H; Heinrich, G; Pelletier, J; Housman, D E

    1995-01-01

    The Wilms' tumor suppressor gene, WT1, encodes a zinc finger polypeptide which plays a key role regulating cell growth and differentiation in the urogenital system. Using the whole-genome PCR approach, we searched murine genomic DNA for high-affinity WT1 binding sites and identified a 10-bp motif 5'GCGTGGGAGT3' which we term WTE). The WTE motif is similar to the consensus binding sequence 5'GCG(G/T)GGGCG3' recognized by EGR-1 and is also suggested to function as a binding site for WT1, setting up a competitive regulatory loop. To evaluate the underlying biochemical basis for such competition, we compared the binding affinities of WT1 and EGR1 for both sequences. WT1 shows a 20- to 30-fold-higher affinity for the WTE sequence compared with that of the EGR-1 binding motif. Mutational analysis of the WTE motif revealed a significant contribution to binding affinity by the adenine nucleotide at the eighth position (5'GCGTGGGAGT3') as well as by the 3'-most thymine (5'GCGTGGGAGT3'), whereas mutations in either flanking nucleotides or other nucleotides in the core sequence did not significantly affect the specific binding affinity. Mutations within WT1 zinc fingers II to IV abolished the sequence-specific binding of WT1 to WTE, whereas alterations within the first WT1 zinc finger reduced the binding affinity approximately 10-fold but did not abolish sequence recognition. We have thus identified a WT1 target, which, although similar in sequence to the EGR-1 motif, shows a 20- to 30-fold-higher affinity for WT1. These results suggest that physiological action of WT1 is mediated by binding sites of significantly higher affinity than the 9-bp EGR-1 binding motif. The role of the thymine base in contributing to binding affinity is discussed in the context of recent structural analysis. PMID:7862142

  6. An investigation on the rheological behavior of metallic semi-solid slurries of Al-6.5 pct Si and semi-solid composite slurries of SiC particulates in an Al-6.5 pct Si alloy matrix

    NASA Technical Reports Server (NTRS)

    Moon, H.-K.; Ito, Y.; Cornie, J. A.; Flemings, M. C.

    1993-01-01

    The rheology of SiC particulate/Al-6.5 pct Si composite slurries was explored. The rheological behavior of the composite slurries shows both thixotropic and pseudoplastic behaviors. Isostructural experiments on the composite slurries revealed a Newtonian behavior beyond a high shear rate limit. The rheology of fully molten composite slurries over the low to high shear rate range indicates the existence of a low shear rate Newtonian region, an intermediate pseudoplastic region and a high shear rate Newtonian region. The isostructural studies indicate that the viscosity of a composite slurry depends upon the shearing history of a given volume of material. An unexpected shear thinning was noted for SiC particulate + alpha slurries as compared to semi-solid metallic slurries at the same fraction solid. The implications of these findings for the processing of slurries into cast components is discussed.

  7. Structures of native and affinity-enhanced WT1 epitopes bound to HLA-A*0201: Implications for WT1-based cancer therapeutics

    SciTech Connect

    Borbulevych, Oleg Y.; Do, Priscilla; Baker, Brian M.

    2010-09-07

    Presentation of peptides by class I or class II major histocompatibility complex (MHC) molecules is required for the initiation and propagation of a T cell-mediated immune response. Peptides from the Wilms Tumor 1 transcription factor (WT1), upregulated in many hematopoetic and solid tumors, can be recognized by T cells and numerous efforts are underway to engineer WT1-based cancer vaccines. Here we determined the structures of the class I MHC molecule HLA-A*0201 bound to the native 126-134 epitope of the WT1 peptide and a recently described variant (R1Y) with improved MHC binding. The R1Y variant, a potential vaccine candidate, alters the positions of MHC charged side chains near the peptide N-terminus and significantly reduces the peptide/MHC electrostatic surface potential. These alterations indicate that the R1Y variant is an imperfect mimic of the native WT1 peptide, and suggest caution in its use as a therapeutic vaccine. Stability measurements revealed how the R1Y substitution enhances MHC binding affinity, and together with the structures suggest a strategy for engineering WT1 variants with improved MHC binding that retain the structural features of the native peptide/MHC complex.

  8. Structures of native and affinity-enhanced WT1 epitopes bound to HLA-A*0201: implications for WT1-based cancer therapeutics.

    PubMed

    Borbulevych, Oleg Y; Do, Priscilla; Baker, Brian M

    2010-09-01

    Presentation of peptides by class I or class II major histocompatibility complex (MHC) molecules is required for the initiation and propagation of a T cell-mediated immune response. Peptides from the Wilms Tumor 1 transcription factor (WT1), upregulated in many hematopoetic and solid tumors, can be recognized by T cells and numerous efforts are underway to engineer WT1-based cancer vaccines. Here we determined the structures of the class I MHC molecule HLA-A*0201 bound to the native 126-134 epitope of the WT1 peptide and a recently described variant (R1Y) with improved MHC binding. The R1Y variant, a potential vaccine candidate, alters the positions of MHC charged side chains near the peptide N-terminus and significantly reduces the peptide/MHC electrostatic surface potential. These alterations indicate that the R1Y variant is an imperfect mimic of the native WT1 peptide, and suggest caution in its use as a therapeutic vaccine. Stability measurements revealed how the R1Y substitution enhances MHC binding affinity, and together with the structures suggest a strategy for engineering WT1 variants with improved MHC binding that retain the structural features of the native peptide/MHC complex. PMID:20619457

  9. Microstructural and thermophysical properties of U-6 wt.%Zr alloy for fast reactor application

    NASA Astrophysics Data System (ADS)

    Kaity, Santu; Banerjee, Joydipta; Nair, M. R.; Ravi, K.; Dash, Smruti; Kutty, T. R. G.; Kumar, Arun; Singh, R. P.

    2012-08-01

    The microstructural and high temperature behavior of U-6 wt.%Zr alloy has been investigated in this study. U-6 wt.%Zr alloy sample for this study was prepared by following injection casting route. The thermophysical properties like coefficient of thermal expansion, specific heat, thermal conductivity of the above alloy were determined. The hot-hardness data of the U-6 wt.%Zr alloy was also generated from room temperature to 973 K. Apart from that, the fuel-clad chemical compatibility with T91 grade steel was also studied by diffusion couple experiment. No studies have been reported on U-6 wt.%Zr alloy. This paper aims at filling up the gap on characterization and thermophysical property evaluation of U-6 wt.%Zr alloy.

  10. Gonad development in Drash and Frasier syndromes depends on WT1 mutations.

    PubMed

    Jaubert, Francis; Vasiliu, Vorel; Patey-Mariaud de Serre, Natacha; Auber, Frédéric; Jeanpierre, Cecile; Gubler, Marie-Claire; Nihoul-Fékété, Claire; Fellous, Marc

    2003-01-01

    The study of the gonads of 8 cases of Drash syndrome (6 ambiguous males, 2 females) and of 2 Frasier syndrome shows that WT1 mutations gives a dysgenetic testis which is the cause of the genital ambiguity observed at birth. By contrast the same mutations have no effect on ovary development giving normal females. However intron mutations in KTS with isoforms imbalance of WT1 proteins cause streak gonads with a female phenotype in XY patients. In consequence WT1 mutations are the cause of a spectrum of male genital malformations associated with glomerulonephritis and tumors. The absence of WT1 protein detection in sertoli cells shown by immunohistochemistry for 3 cases suggests an imprinting effect of the normal WT1 allele promotor rather than a low level of protein production. A caryotype is mandatory for a correct diagnosis. PMID:15357247

  11. Final Report - IHLW PCT, Spinel T1%, Electrical Conductivity, and Viscosity Model Development, VSL-07R1240-4

    SciTech Connect

    Kruger, Albert A.; Piepel, Gregory F.; Landmesser, S. M.; Pegg, I. L.; Heredia-Langner, Alejandro; Cooley, Scott K.; Gan, H.; Kot, W. K.

    2013-11-13

    This report is the last in a series of currently scheduled reports that presents the results from the High Level Waste (HLW) glass formulation development and testing work performed at the Vitreous State Laboratory (VSL) of the Catholic University of America (CUA) and the development of IHLW property-composition models performed jointly by Pacific Northwest National Laboratory (PNNL) and VSL for the River Protection Project-Waste Treatment and Immobilization Plant (RPP-WTP). Specifically, this report presents results of glass testing at VSL and model development at PNNL for Product Consistency Test (PCT), one-percent crystal fraction temperature (T1%), electrical conductivity (EC), and viscosity of HLW glasses. The models presented in this report may be augmented and additional validation work performed during any future immobilized HLW (IHLW) model development work. Completion of the test objectives is addressed.

  12. Effect of 0.1 at. pct Zirconium on the cyclic oxidation resistance of beta-NiAl

    NASA Technical Reports Server (NTRS)

    Barrett, Charles A.

    1988-01-01

    The effect of 0.1 at. pct Zr on the cyclic oxidation of hipped beta-NiAl was studied. Oxidation testing was performed in static air at 1100-1200 C, using 1-hr exposure cycles for test times up to 3000 hr. The weight change versus time data were modeled with the COSP computer program to analyze and predict cyclic-oxidation behavior. Zr additions significantly change the nature of the scale-spalling process during cooling, so that the oxide spalls near the oxide-air interface at a relatively low depth within the scale. Without Zr, the predominantly alpha-Al2O3 scale tends to spall randomly to bare metal at relatively high effective-scale-loss rates, particularly at 1150 C and 1200 C. This leads to higher rates of Al consumption for the Zr-free aluminide and much earlier depletion of Al, leading to eventual breakaway (i.e., failure).

  13. Analysis of NiAlTa precipitates in beta-NiAl + 2 at. pct Ta alloy

    NASA Technical Reports Server (NTRS)

    Pathare, V.; Michal, G. M.; Vedula, K.; Nathal, M. V.

    1987-01-01

    Results are reported from experiments performed to identify the precipitates, and their orientation in the matrix, in a beta-NiAl alloy containing 2 at. pct. Ta after undergoing creep test at 1300 K. Test specimens formed by extruding hot powders were compressed at 1300 K for about 50 hr at a strain rate averaging 6/1 million per sec. The specimens were then thinned and examined under an electron microscope and by X-ray diffractometry. An intermetallic NiAlTa compound with a hexagonal Cl4 structure appeared as second phase precipitates in the samples, exhibiting plate-like shapes and a habit plane close to (012). The prism planes of the hexagonal NiAlTa precipitates paralleled the closest packed planes in the cubic beta-NiAl matrix.

  14. Corrosion behavior of austenitic steels in liquid lead bismuth containing 10-6 wt% and 10-8 wt% oxygen at 400-500 °C

    NASA Astrophysics Data System (ADS)

    Heinzel, A.; Weisenburger, A.; Müller, G.

    2014-05-01

    Three austenitic steels (316L, DIN 1.4970 tube and rod material) were tested up to 5000 h at temperatures between 400 and 500 °C in PbBi containing 10-8 wt% oxygen and at 450 °C and 500 °C in PbBi with 10-6 wt% oxygen. Protective scales grown on the surface up to 450 °C consist mainly of Cr rich oxides. However, after 5000 h at 500 °C dissolution attack occurred. At 10-6 wt% and 450 °C the thin Cr rich oxide scale is interrupted by areas with a thicker duplex-layered oxide of magnetite and spinel. At the higher temperature of 500 °C the whole surface is covered by the duplex-layered oxide scale.

  15. Osr1 Interacts Synergistically with Wt1 to Regulate Kidney Organogenesis.

    PubMed

    Xu, Jingyue; Liu, Han; Chai, Ok Hee; Lan, Yu; Jiang, Rulang

    2016-01-01

    Renal hypoplasia is a common cause of pediatric renal failure and several adult-onset diseases. Recent studies have associated a variant of the OSR1 gene with reduction of newborn kidney size and function in heterozygotes and neonatal lethality with kidney defects in homozygotes. How OSR1 regulates kidney development and nephron endowment is not well understood, however. In this study, by using the recently developed CRISPR genome editing technology, we genetically labeled the endogenous Osr1 protein and show that Osr1 interacts with Wt1 in the developing kidney. Whereas mice heterozygous for either an Osr1 or Wt1 null allele have normal kidneys at birth, most mice heterozygous for both Osr1 and Wt1 exhibit defects in metanephric kidney development, including unilateral or bilateral kidney agenesis or hypoplasia. The developmental defects in the Osr1+/-Wt1+/- mouse embryos were detected as early as E10.5, during specification of the metanephric mesenchyme, with the Osr1+/-Wt1+/- mouse embryos exhibiting significantly reduced Pax2-positive and Six2-positive nephron progenitor cells. Moreover, expression of Gdnf, the major nephrogenic signal for inducing ureteric bud outgrowth, was significantly reduced in the metanephric mesenchyme in Osr1+/-Wt1+/- embryos in comparison with the Osr1+/- or Wt1+/- littermates. By E11.5, as the ureteric buds invade the metanephric mesenchyme and initiate branching morphogenesis, kidney morphogenesis was significantly impaired in the Osr1+/-Wt1+/- embryos in comparison with the Osr1+/- or Wt1+/- embryos. These results indicate that Osr1 and Wt1 act synergistically to regulate nephron endowment by controlling metanephric mesenchyme specification during early nephrogenesis. PMID:27442016

  16. Osr1 Interacts Synergistically with Wt1 to Regulate Kidney Organogenesis

    PubMed Central

    Xu, Jingyue; Liu, Han; Chai, Ok Hee; Jiang, Rulang

    2016-01-01

    Renal hypoplasia is a common cause of pediatric renal failure and several adult-onset diseases. Recent studies have associated a variant of the OSR1 gene with reduction of newborn kidney size and function in heterozygotes and neonatal lethality with kidney defects in homozygotes. How OSR1 regulates kidney development and nephron endowment is not well understood, however. In this study, by using the recently developed CRISPR genome editing technology, we genetically labeled the endogenous Osr1 protein and show that Osr1 interacts with Wt1 in the developing kidney. Whereas mice heterozygous for either an Osr1 or Wt1 null allele have normal kidneys at birth, most mice heterozygous for both Osr1 and Wt1 exhibit defects in metanephric kidney development, including unilateral or bilateral kidney agenesis or hypoplasia. The developmental defects in the Osr1+/-Wt1+/- mouse embryos were detected as early as E10.5, during specification of the metanephric mesenchyme, with the Osr1+/-Wt1+/- mouse embryos exhibiting significantly reduced Pax2-positive and Six2-positive nephron progenitor cells. Moreover, expression of Gdnf, the major nephrogenic signal for inducing ureteric bud outgrowth, was significantly reduced in the metanephric mesenchyme in Osr1+/-Wt1+/- embryos in comparison with the Osr1+/- or Wt1+/- littermates. By E11.5, as the ureteric buds invade the metanephric mesenchyme and initiate branching morphogenesis, kidney morphogenesis was significantly impaired in the Osr1+/-Wt1+/- embryos in comparison with the Osr1+/- or Wt1+/- embryos. These results indicate that Osr1 and Wt1 act synergistically to regulate nephron endowment by controlling metanephric mesenchyme specification during early nephrogenesis. PMID:27442016

  17. The effects of a SiO2 coating on the corrosion parameters cpTi and Ti-6Al-7Nb alloy

    PubMed Central

    Basiaga, Marcin; Walke, Witold; Paszenda, Zbigniew; Karasiński, Paweł; Szewczenko, Janusz

    2014-01-01

    The aim of this paper was to evaluate the usefulness of the sol-gel method application, to modificate the surface of the Ti6Al7Nb alloy and the cpTi titanium (Grade 4) with SiO2 oxide, applied on the vascular implants to improve their hemocompatibility. Mechanical treatment was followed by film deposition on surface of the titanium samples. An appropriate selection of the process parameters was verified in the studies of corrosion, using potentiodynamic and impedance method. A test was conducted in the solution simulating blood vessels environment, in simulated body fluid at t = 37.0 ± 1 °C and pH = 7.0 ± 0.2. Results showed varied electrochemical properties of the SiO2 film, depending on its deposition parameters. Correlations between corrosion resistance and layer adhesion to the substrate were observed, depending on annealing temperature. PMID:25482412

  18. Effect of Friction Stir Processing on Microstructure and Tensile Properties of an Investment Cast Al-7Si-0.6Mg Alloy

    SciTech Connect

    Jana, Saumyadeep; Mishra, Rajiv S.; Baumann, John B.; Grant, Glenn J.

    2010-10-01

    Friction stir processing (FSP) is emerging as a promising tool for microstructural modification. The present study assesses the effects of FSP on the microstructure and mechanical properties of an investment cast Al-7Si-Mg alloy. FSP eliminates porosity and significantly refines eutectic Si particles. The extent of particle refinement varied with changes in processing conditions. High tool rotation rate and low to intermediate tool traverse speed generated a higher volume fraction of finer particles. Tensile ductility changed significantly as a result of FSP, whereas UTS improved only marginally. Yield strength was similar in both cast and FSPed samples under various heat treated conditions, with the highest value obtained after a T6 heat treatment. Further, FSP caused significant grain refinement in the stir zone, subsequently transforming into very coarse grains as abnormal grain growth (AGG) occurred during solution treatment at high temperature.

  19. Regulation of WT1 by phosphorylation: inhibition of DNA binding, alteration of transcriptional activity and cellular translocation.

    PubMed Central

    Ye, Y; Raychaudhuri, B; Gurney, A; Campbell, C E; Williams, B R

    1996-01-01

    Phosphorylation is one of the major post-translational mechanisms by which the activity of transcription factors is regulated. We have investigated the role of phosphorylation in the regulation of nucleic acid binding activity and the nuclear translocation of WT1. Two recombinant WT1 proteins containing the DNA binding domain with or without a three amino acid (KTS) insertion (WT1ZF + KTS and WT1ZF - KTS) were strongly phosphorylated by protein kinase A (PKA) and protein kinase C (PKC) in vitro. Both PKA and PKC phosphorylation inhibited the ability of WT1ZF + KTS or WT1ZF - KTS to bind to a sequence derived from the WT1 promoter region in gel mobility shift assays. The binding of WT1ZF - KTS to an EGR1 consensus binding site was also inhibited by prior PKA and PKC phosphorylation. We also demonstrate the RNA binding activity of WT1, but this was not altered by phosphorylation. PKA activation by dibutyryl cAMP in WT1-transfected cells resulted in the reversal of WT1 suppression of a reporter construct. Although WT1 protein is predominantly localized to the nucleus, this expression pattern is altered upon PKA activation, resulting in the cytoplasmic retention of WT1. Accordingly, phosphorylation may play a role in modulating the transcriptional regulatory activity of WT1 through interference with nuclear translocation, as well as by inhibition of WT1 DNA binding. Images PMID:8896454

  20. Crack initiation and propagation in 50.9 at. pct Ni-Ti pseudoelastic shape-memory wires in bending-rotation fatigue

    NASA Astrophysics Data System (ADS)

    Sawaguchi, Tak Ahiro; Kausträter, Gregor; Yawny, Alejandro; Wagner, Martin; Eggeler, Gunther

    2003-12-01

    The structural fatigue of pseudoelastic Ni-Ti wires (50.9 at. pct Ni) was investigated using bending-rotation fatigue (BRF) tests, where a bent and otherwise unconstrained wire was forced to rotate at different rotational speeds. The number of cycles to failure ( N f ) was measured for different bending radii and wire thicknesses (1.0, 1.2, and 1.4 mm). The wires consisted of an alloy with a 50-nm grain size, no precipitates, and some TiC inclusions. In BRF tests, the surface of the wire is subjected to tension-compression cycles, and fatigue lives can be related to the maximum tension and compression strain amplitudes ( ɛ a ) in the wire surface. The resulting ɛ a - N f curves can be subdivided into three regimes. At ɛ a > 1 pct rupture occurs early (low N f ) and the fatigue-rupture characteristics were strongly dependent on ɛ a and the rotational speed (regime 1). For 0.75 pct < ɛ a < 1 pct, fatigue lives strongly increase and are characterized by a significant statistical scatter (regime 2). For ɛ a < 0.75 pct, no fatigue rupture occurs up to cycle numbers of 106 (regime 3). Using scanning electron microscopy (SEM), it was shown that surface cracks formed in regions with local stress raisers (such as inclusions and/or scratches). The growth of surface cracks during fatigue loading produced striations on the rupture surface; during final rupture, ductile voids form. The microstructural details of fatigue-damage accumulation during BRF testing are described and discussed.

  1. Electrical conductivity and mechanical properties of Cu-0.7wt% Cr and Cu-1.0wt% Cr alloys processed by severe plastic deformation

    NASA Astrophysics Data System (ADS)

    Kommel, L.; Pokatilov, A.

    2014-08-01

    As-cast Cu-0.7wt% Cr and Cu-1.0wt% Cr alloys were subjected to equal-channel angular pressing (ECAP), hard cyclic viscoplastic (HCV) deformation and post deformation heat treatment for receiving an ultrafine grained material with a combination of high strength, good wear resistance and high electric conductivity. Samples from Cu-0.7wt% Cr alloy were processed up to six passes and Cu-1wt% Cr alloy samples were processed up to four passes of ECAP via Bc route. HCV deformation of samples was conducted by frequency of 0.5 Hz for 20 cycles at tension-compression strain amplitudes of +/-0.05%, +/-0.1%, +/-0.5%, +/-1% and +/-1.5%, respectively. During HCV deformation, as-cast Cu-0./wt% Cr alloy show fully viscoelastic behavior at strain/stress amplitude of +/-0.05% while ECAP processed material show the same behavior at strain amplitude of +/-0.1%. The Young modulus was increased from ~120 GPa up to ~150 GPa. The results illustrated that specific volume wear decrease with increasing of hardness but the measured coefficient of friction (COF ~ 0.6) was approximately the same for all samples at the end of wear testing. The hardness after ECAP for 6 passes by Bc route was 192HV0.1 and electric conduction 74.16% IACS, respectively. By this the as-cast Cu-0./wt% Cr alloy (heat treated at 1000 °C for 2h) has microhardness ~70HV0.1 and electrical conductivity of ~40% IACS. During aging at the temperatures in the interval of 250-550 °C for 1h the hardness and electrical conductivity were stabilized to mean values of 120+/-5HV0.1 and to 93.4+/-0.3% IACS, respectively. The hardness and electric conductivity took decrease by temperature increase over ~550 °C, respectively. The results of present experimental investigation show that UFG Cu- 0.7wt% Cr alloy with compare to Cu-1.0% Cr alloy is a highly electrical conductive and high temperature wear resistant material for using in electrical industry.

  2. Experimental determination of the H2O + 15 wt% NaCl and H2O + 25 wt% NaCl liquidi to 1.4 GPa

    NASA Astrophysics Data System (ADS)

    Valenti, P.; Schmidt, C.

    2009-12-01

    The binary H2O+NaCl is one of the most important model systems for chloridic fluids in many geologic environments such as the Earth’s crust, upper mantle, and subducting slabs, and is also applicable to extraterrestrial icy planetary bodies (e.g., Manning 2004, Zolensky et al., 1999). The knowledge on phase equilibria and PVTx properties of this system is still fragmentary at high pressures, e.g., very little has been reported on liquidi at compositions <30 wt% NaCl (Manning and Daniel 2008). In this study, we investigated the liquidus of 15 and 25 wt% NaCl solutions at pressures up to 1.4 GPa. The experiments were performed using a hydrothermal diamond-anvil cell (Bassett et al. 1993) modified for Raman spectroscopy and accurate temperature measurements. A quartz chip, halite, and water were loaded into the sample chamber, which also contained a small trapped air bubble (10 vol%) when it was sealed. The actual salinity was then determined from measurement of the vapor-saturated liquidus temperature. The sample chamber was then compressed until the bubble disappeared. After freezing, phase transitions occurring with increasing temperature were observed optically, and the pressure was determined from the frequency shift of the 464 cm-1 Raman line of quartz (Schmidt and Ziemann 2000). The sample chamber was then compressed further, and the experiment was repeated at various bulk densities until a pressure of ~1.4 GPa was attained. At some conditions, Raman spectra were acquired for identification of the phase assemblage. The solution always crystallized to a single phase upon cooling above ~0.15 GPa at 25 wt% NaCl and above ~1 GPa at 15 wt% NaCl. Raman spectra in the OH stretching region indicate that this phase contains or is a NaCl hydrate other than hydrohalite, probably in solid solution with ice. Melting of this phase produced liquid and hydrohalite and/or ice VI. Ice VI was the last solid that dissolved upon heating, between 1100 MPa, 3 °C and 1370 MPa, 17

  3. Fe-24 wt.%Cr-4.1 wt.%C hardfacing alloy: Microstructure and carbide refinement mechanisms with ceria additive

    SciTech Connect

    Zhou, Y.F.; Yang, Y.L.; Jiang, Y.W.; Yang, J.; Ren, X.J.; Yang, Q.X.

    2012-10-15

    The microstructure and carbide refinement mechanisms of Fe-24 wt.%Cr-4.1 wt.%C hardfacing alloys with 0 wt.%, 0.5 wt.%, 1.0 wt.%, 2 wt.%, and 4 wt.% ceria additives have been systematically investigated in this work. Optical microscopy, field emission scanning electron microscopy with energy dispersive spectrometer, and X-ray diffraction were collectively used to study the microstructure, the phase components, and the chemical formation of inclusion formed in the welding process. Wear-resistance of the alloys was comparatively studied using an abrasive wear testing machine. The structure analysis results show that the Fe-Cr-C hardfacing alloy mainly consists of martensite, retained austenite, MC carbide and M{sub 7}C{sub 3} carbide. With increasing ceria additive contents, the average size of the primary M{sub 7}C{sub 3} carbide decreases and reaches a most refined state in the alloy with 2 wt.% ceria additives. Comparative wear tests data shows that the wear resistance of the hardfacing alloys with ceria additives is better than that without ceria additive. In a good agreement with the carbide refinement results, the wear resistance of the alloy reaches an optimum level in the sample with 2 wt.% ceria additive. The main RE inclusion type identified with in-situ XRD analysis is RE inclusion Ce{sub 2}O{sub 2}S. Thermodynamics calculation confirms that this type of RE inclusion could precipitate prior to M{sub 7}C{sub 3} carbides, and act as a heterogeneous nucleus for M{sub 7}C{sub 3} in the welding process, which effectively provides a mechanism for significant refinement of the M{sub 7}C{sub 3} carbide and improves its wear resistance. - Graphical Abstract: Rare Earth inclusion (Ce{sub 2}O{sub 2}S) distributes in the primary M{sub 7}C{sub 3} carbide. Moreover, Ce{sub 2}O{sub 2}S, which acts as heterogeneous nuclei of the primary M{sub 7}C{sub 3} carbide, is medium effective. Therefore, the primary M{sub 7}C{sub 3} carbide has been refined. Highlights: Black

  4. Effect of annealing temperature on the microstructure and mechanical properties of an as-rolled Mg-9wt.%Li-3wt.%Al-1wt.%Zn alloy sheet

    NASA Astrophysics Data System (ADS)

    Lin, Meng-Chang; Lin, Shang-Qiu; Uan, Jun-Yen

    2014-09-01

    This study investigated the effect of annealing temperature on the mechanical properties of an as-rolled Mg-9.26wt.%Li-3.03wt.%Al-1.10wt.%Zn (LAZ931) alloy sheet. The dual-phase (α + β) LAZ931 alloy plate of 3 mm in thickness were rolled (67% reduction) and then annealed at temperatures at 100°C-350°C. The alloy's ductility showed a sharp concave downward tendency as a function of annealing temperature. The elongation of the LAZ931 alloy sheet increased with annealing temperature up to 150°C, followed by a sharp decrease of the alloy's ductility as the annealing temperature higher than 150°C. The specimen exhibited an extremely low elongation (only ˜0.5%) at annealing temperature around 300°C. Formation of brittle AlLi particles on boundary resulted in Li depletion zone near by grain boundary, transforming the Li depletion zone into α (hcp) layer. The combined effects including brittle AlLi particles on boundary and the hcp α layer on boundary resulted in the brittlement of the high-temperature-annealing sample.

  5. Immunotherapy in Acute Leukemias: Implications and Perspectives Using Wt1 Antigen.

    PubMed

    Cebinelli, Guilherme Cesar Martelossi; DE Sousa Pereira, Nathália; Sena, Michelle Mota; DE Oliveira, Carlos Eduardo Coral; Fujita, Thiago Cezar; DA Rocha, Sérgio Paulo Dejato; DE Abreu Oliveira, Francisco José; Marinello, Poliana Camila; Watanabe, Maria Angelica Ehara

    2016-08-01

    The WT1 gene encodes a transcription factor involved in regulation of many cellular processes, including proliferation, differentiation, mRNA processing and apoptosis, besides acting as a transcription repressor of growth factors and their receptors' genes. This gene is expressed at high levels in several types of cancers, including acute leukemias. In this regard, many studies have identified WT1 protein as a tumor antigen, considered a target molecule for clinical application in human acute leukemias. Immunotherapy using WT1 antigen has been effective in stimulating immune responses against leukemic cells. Regarding adoptive immunotherapy, the use of dendritic cells (DCs) for the WT1-specific cytotoxic T cells generation proved to be efficient in the development and maintenance of immunologic cells. Therefore, these therapeutic methods, that provided enthusiasm for moving ahead, highlight several opportunities and challenges to be used in clinical practice for managing acute leukemias. PMID:27466479

  6. Characterization and property evaluation of U-15 wt%Pu alloy for fast reactor

    NASA Astrophysics Data System (ADS)

    Kaity, Santu; Banerjee, Joydipta; Ravi, K.; Keswani, R.; Kutty, T. R. G.; Kumar, Arun; Prasad, G. J.

    2013-02-01

    The characterization and high temperature behaviour of U-15 wt%Pu alloy has been investigated in this study for the first time. U-15 wt%Pu alloy sample for this study was prepared by following melting and casting route. Microstructural characterization of the alloy was carried out by XRD and optical microscopy. The thermophysical properties like phase transition temperatures, coefficient of thermal expansion and hot hardness of the above alloy were determined. Eutectic temperature between T91 and U-15 wt%Pu was established. Apart from that, the fuel-cladding chemical compatibility of U-15 wt%Pu alloy with T91 grade steel was studied by diffusion couple experiment.

  7. Television interference measurements near the MOD-2 WT array at Goodnoe Hills, Washington

    SciTech Connect

    Sengupta, D L; Senior, T B.A.; Ferris, J E

    1983-11-01

    Electromagnetic interference to television reception caused by the MOD-2 wind turbine (WT) array at Goodnoe Hills, Washington, was studied by means of detailed measurements at a number of test sites in the vicinity of the WT array. The commercial television signals available in the area were used as the radio frequency sources during the measurements. The dynamic measurements indicated that varying amounts of TVI were produced at all sites and on some or all of the available TV channels; with the directional antenna in use, most of the backward region interference produced video distortion that was judged to be acceptable; at one test location about 1-1/2 miles from the WT array site, forward region interference was observed; when the blades of the WTs rotate in synchronism, they tend to increase the amplitude of the interference pulses, thereby producing more TVI effects; and when the blades do not rotate in synchronism, each WT produces interference effects individually.

  8. Alternative splicing of Wilms tumor suppressor 1 (Wt1) exon 4 results in protein isoforms with different functions.

    PubMed

    Schnerwitzki, Danny; Perner, Birgit; Hoppe, Beate; Pietsch, Stefan; Mehringer, Rebecca; Hänel, Frank; Englert, Christoph

    2014-09-01

    The Wilms tumor suppressor gene Wt1 encodes a zinc finger transcription factor that is essential for development of multiple organs including kidneys, gonads, spleen and heart. In mammals Wt1 comprises 10 exons with two characteristic splicing events: inclusion or skipping of exon 5 and alternative usage of two splice donor sites between exons 9 and 10. Most fish including zebrafish and medaka possess two wt1 paralogs, wt1a and wt1b, both lacking exon 5. Here we have characterized wt1 in guppy, platyfish and the short-lived African killifish Nothobranchius furzeri. All fish except zebrafish show alternative splicing of exon 4 of wt1a but not of wt1b with the wt1a(-exon 4) isoform being the predominant splice variant. With regard to function, Wt1a(+exon 4) showed less dimerization but stimulated transcription more effectively than the Wt1a(-exon 4) isoform. A specific knockdown of wt1a exon 4 in zebrafish was associated with anomalies in kidney development demonstrating a physiological function for Wt1a exon 4. Interestingly, alternative splicing of exon 4 seems to be an early evolutionary event as it is observed in the single wt1 gene of the sturgeon, a species that has not gone through teleost-specific genome duplication. PMID:25014653

  9. Diagnostic utility of WT-1 cytoplasmic stain in variety of vascular lesions

    PubMed Central

    Galfione, Sarah K; Ro, Jae Y; Ayala, Alberto G; Ge, Yimin

    2014-01-01

    Vascular lesions are commonly encountered in routine pathologic practice and often pose diagnostic challenges owing to their morphologic diversity. Although WT-1 expression was reported in some vascular tumors, little is known about its staining patterns in a spectrum of vascular lesions from various locations. We examined WT-1 immunostain in 95 cases of vascular lesions including angiosarcomas (AS, 19 cases), hemangioendotheliomas (HE, 5), Kaposi’s sarcomas (KS, 4), cavernous hemangiomas (CVH, 12), capillary hemangiomas (CPH, 7), pyogenic granulomas (PG, 4), lymphangiomas (LA, 4), hemangiopericytomas (HP, 5), glomus tumors (GT, 8), vascular malformation (VM, 13) and granulation tissue (GRT, 14). Strong WT-1 cytoplasmic stain was invariably observed in all cases of malignant and borderline vascular tumors including AS (19/19), KS (4/4) and HE (5/5). WT-1 was also consistently expressed in CPH (7/7), PG (4/4), and GRT (14/14), while it became weaker in VM (10/13) and often negative in CVH (2/12) and LA (0/4). WT1 stain was not demonstrated in HP (0/5) and rarely in GT (2/8). We conclude that consistent and diffuse WT-1 cytoplasmic stain in AS, HE and KS can be useful in distinguishing these tumors from poorly differentiated tumors with mimicking features. On the other hand, reliable WT-1 stain in CPH, PG and GRT may help in differential diagnosis with non-endothelial vascular tumors such as GT and HP. Recognizing the WT-1 cytoplasmic stain in a broad spectrum of benign and neoplastic tissues is critical in formulating appropriate immunohistochemical panels and avoiding misinterpretation of results. PMID:24966966

  10. Microstructural evolution of a uranium-10 wt.% molybdenum alloy for nuclear reactor fuels

    NASA Astrophysics Data System (ADS)

    Clarke, A. J.; Clarke, K. D.; McCabe, R. J.; Necker, C. T.; Papin, P. A.; Field, R. D.; Kelly, A. M.; Tucker, T. J.; Forsyth, R. T.; Dickerson, P. O.; Foley, J. C.; Swenson, H.; Aikin, R. M.; Dombrowski, D. E.

    2015-10-01

    Low-enriched uranium-10 wt.% molybdenum (LEU-10wt.%Mo) is of interest for the fabrication of monolithic fuels to replace highly-enriched uranium (HEU) dispersion fuels in high performance research and test reactors around the world. In this work, depleted uranium-10 wt.%Mo (DU-10wt.%Mo) is used to simulate the solidification and microstructural evolution of LEU-10wt.%Mo. Electron backscatter diffraction (EBSD) and complementary electron probe microanalysis (EPMA) reveal significant microsegregation present in the metastable γ-phase after solidification. Homogenization is performed at 800 and 1000 °C for times ranging from 1 to 32 h to explore the time-temperature combinations that will reduce the extent of microsegregation, as regions of higher and lower Mo content may influence local mechanical properties and provide preferred regions for γ-phase decomposition. We show for the first time that EBSD can be used to qualitatively assess microstructural evolution in DU-10wt.%Mo after homogenization treatments. Complementary EPMA is used to quantitatively confirm this finding. Homogenization at 1000 °C for 2-4 h may the regions that contain 8 wt.% Mo or lower, whereas homogenization at 1000 °C for longer than 8 h effectively saturates Mo chemical homogeneity, but results in substantial grain growth. The appropriate homogenization time will depend upon additional microstructural considerations, such as grain growth and intended subsequent processing. Higher carbon LEU-10wt.%Mo generally contains more inclusions within the grains and at grain boundaries after solidification. The effect of these inclusions on microstructural evolution (e.g. grain growth) during homogenization and as potential γ-phase decomposition nucleation sites is unclear, but likely requires additional study.

  11. WT1 recruits TET2 to regulate its target gene expression and suppress leukemia cell proliferation

    PubMed Central

    Wang, Yiping; Xiao, Mengtao; Chen, Xiufei; Chen, Leilei; Xu, Yanping; Lv, Lei; Wang, Pu; Yang, Hui; Ma, Shenghong; Lin, Huaipeng; Jiao, Bo; Ren, Ruibao; Ye, Dan; Guan, Kun-Liang; Xiong, Yue

    2015-01-01

    The TET2 DNA dioxygenase regulates cell identity and suppresses tumorigenesis by modulating DNA methylation and expression of a large number of genes. How TET2, like most other chromatin modifying enzymes, is recruited to specific genomic sites is unknown. Here we report that WT1, a sequence-specific transcription factor, is mutated in a mutually exclusive manner with TET2, IDH1 and IDH2 in acute myeloid leukemia (AML). WT1 physically interacts with and recruits TET2 to its target genes to activate their expression. The interaction between WT1 and TET2 is disrupted by multiple AML-derived TET2 mutations. TET2 suppresses leukemia cell proliferation and colony formation in a manner dependent on WT1. These results provide a mechanism for targeting TET2 to specific DNA sequence in the genome. Our results also provide an explanation for the mutual exclusivity of WT1 and TET2 mutations in AML and suggest an IDH1/2-TET2-WT1 pathway in suppressing AML. PMID:25601757

  12. WT1 targets Gas1 to maintain nephron progenitor cells by modulating FGF signals

    PubMed Central

    Kann, Martin; Bae, Eunnyung; Lenz, Maximilian O.; Li, Liangji; Trannguyen, BaoTran; Schumacher, Valerie A.; Taglienti, Mary E.; Bordeianou, Liliana; Hartwig, Sunny; Rinschen, Markus M.; Schermer, Bernhard; Benzing, Thomas; Fan, Chen-Ming; Kreidberg, Jordan A.

    2015-01-01

    Development of the metanephric kidney depends on tightly regulated interplay between self-renewal and differentiation of a nephron progenitor cell (NPC) pool. Several key factors required for the survival of NPCs have been identified, including fibroblast growth factor (FGF) signaling and the transcription factor Wilms' tumor suppressor 1 (WT1). Here, we present evidence that WT1 modulates FGF signaling by activating the expression of growth arrest-specific 1 (Gas1), a novel WT1 target gene and novel modulator of FGF signaling. We show that WT1 directly binds to a conserved DNA binding motif within the Gas1 promoter and activates Gas1 mRNA transcription in NPCs. We confirm that WT1 is required for Gas1 expression in kidneys in vivo. Loss of function of GAS1 in vivo results in hypoplastic kidneys with reduced nephron mass due to premature depletion of NPCs. Although kidney development in Gas1 knockout mice progresses normally until E15.5, NPCs show decreased rates of proliferation at this stage and are depleted as of E17.5. Lastly, we show that Gas1 is selectively required for FGF-stimulated AKT signaling in vitro. In summary, our data suggest a model in which WT1 modulates receptor tyrosine kinase signaling in NPCs by directing the expression of Gas1. PMID:25804736

  13. Breakdown of compensation and persistence of nonsaturating magnetoresistance in gated WT e2 thin flakes

    NASA Astrophysics Data System (ADS)

    Wang, Yilin; Wang, Kefeng; Reutt-Robey, Janice; Paglione, Johnpierre; Fuhrer, Michael S.

    2016-03-01

    The recently discovered large nonsaturating magnetoresistance in semimetal WT e2 may result from near-perfect electron-hole compensation, however recent reports question whether the compensation is adequate to explain the observations. Experiments on significantly uncompensated WT e2 are needed. We measure magnetoresistance ρx x(H ) , Hall effect ρx y(H ) , and an electrolyte gating effect in thin (<100 nm) exfoliated WT e2 . We observe ρx y(H ) linear in H at low H consistent with near-perfect compensation, however ρx y(H ) becomes nonlinear and changes sign with increasing H , implying a breakdown of compensation. We break compensation more significantly by using an electrolytic gate for highly electron-doped WT e2 with Li. In gated WT e2 the nonsaturating ρx x(H ) persists to H = 14 T , even with significant deviation from perfect electron-hole compensation (p /n = 0.84 ) where the two-band model predicts a saturating ρx x(H ) . Our results indicate electron-hole compensation is not the mechanism for extremely large magnetoresistance in WT e2 ; alternative explanations are needed.

  14. The effect of chemical composition on the PCT durability of mixed waste glasses from wastewater treatment sludges

    SciTech Connect

    Resce, J.L.; Ragsdale, R.G.; Overcamp, T.J.; Bickford, D.F.; Cicero, C.A.

    1995-01-25

    An experimental program has been designed to examine the chemical durability of glass compositions derived from the vitrification of simulated wastewater treatment sludges. These sludges represent the majority of low-level mixed wastes currently in need of treatment by the US DOE. The major oxides in these model glasses included SiO{sub 2}, Al{sub 2}O{sub 3}, B{sub 2}O{sub 3}, Na{sub 2}O, CaO and Fe{sub 2}O{sub 3}. In addition, three minor oxides, BaO, NiO, and PbO, were added as hazardous metals. The major oxides were each varied at two levels resulting in 32 experimental glasses. The chemical durability was measured by the 7-Day Product Consistency Test (PCT). The normalized sodium release rates (NRR{sub Na}) of these glasses ranged from 0.01 to 4.99 g/m{sup 2}. The molar ratio of the glass-former to glass-modifier (F/M) was found to have the greatest effect on PCT durability. Glass-formers included SiO{sub 2}, Al{sub 2}O{sub 3}, and B{sub 2}O{sub 3}, while Na{sub 2}O, CaO, BaO, NiO, and PbO were glass-modifiers. As this ratio increased from 0.75 to 2.0, NRR{sub Na} was found to decrease between one and two orders of magnitude. Another important effect on NRR{sub Na} was the Na{sub 2}O/CaO ratio. As this ratio increased from 0.5 to 2.0, NRR{sub Na} increased up to two orders of magnitude for the glasses with the low F/M ratio but almost no effect was observed for the glasses with the high F/M ratio. Increasing the iron oxide content from 2 to 18 mole% was found to decrease NRR{sub Na} one order of magnitude for the glasses with low F/M but iron had little effect on the glasses with the high F/M ratio. The durability also increased when 10 mole percent Al{sub 2}O{sub 3} was included in low iron oxide glasses but no effect was observed with the high iron glasses. The addition of B{sub 2}O{sub 3} had little effect on durability. The effects of other composition parameters on durability are discussed as well.

  15. Microstructural evolution and intermetallic formation in Al-8wt% Si-0.8wt% Fe alloy due to grain refiner and modifier additions

    NASA Astrophysics Data System (ADS)

    Hassani, Amir; Ranjbar, Khalil; Sami, Sattar

    2012-08-01

    An alloy of Al-8wt% Si-0.8wt% Fe was cast in a metallic die, and its microstructural changes due to Ti-B refiner and Sr modifier additions were studied. Apart from usual refinement and modification of the microstructure, some mutual influences of the additives took place, and no mutual poisoning effects by these additives, in combined form, were observed. It was noticed that the dimensions of the iron-rich intermetallics were influenced by the additives causing them to become larger. The needle-shaped intermetallics that were obtained from refiner addition became thicker and longer when adding the modifier. It was also found that α-Al and eutectic silicon phases preferentially nucleate on different types of intermetallic compounds. The more iron content of the intermetallic compounds and the more changes in their dimensions occurred. Formation of the shrinkage porosities was also observed.

  16. Observations of Guinier-Preston zones in an as-deposited Al-1wt.%Si-0.5wt.%Cu thin film

    SciTech Connect

    Tung, C.H.; Chiu, R.L.; Chang, P.H.

    1996-05-01

    Aluminum-copper (Al-Cu) and aluminum-silicon-copper (Al-Si-Cu) films are widely used as interconnects and contacts in contemporary very large scale integration (VLSI) technology. Cu alloying in Al results in the formation of intermetallic Al{sub 2}Cu precipitates, which increase corrosion susceptibility as well as process difficulty. Understanding the formation of Al2Cu theta-phase precipitates within Al alloy thin films is thus of great scientific and technical value. For the first time Guinier-Preston zones are observed by HRTEM to form on Al{l_brace}111{r_brace} planes in an as-deposited Al-1wt%Si-0.5wt%Cu thin films sputtered on oxidized Si substrate. At present time the chemical nature (Si or Cu) of the precipitation in the observed GP zones is still uncertain.

  17. Characterization of the tribological coating composition 77 wt % CaF2 - 23 wt % Li F fused to IN-750 alloy

    NASA Technical Reports Server (NTRS)

    Deadmore, D. L.; Sliney, H. E.

    1986-01-01

    A coating composed of 77 wt % CaF2 - 23 wt % LiF fused on IN-750 nickel-based alloy was studied using SEM, XRD, EDX, and optical microscopic methods. The surfaces examined were the as-fused coating with no subsequent treatment, the coating after ultrasonic cleaning in water, and the uncoated polished and etched metal. It was found that the coating reacts during fusion with Ti and Nb rich inclusions in the alloy. Numerous small rectangular crystallites of Ca(Ti,Nb) oxide are formed beneath an overlay of fused fluoride composition. These crystallines are stubby and appear to be embedded in the metal substrate surface. It is known from previous studies that this coating-alloy system has good tribological properties in extreme conditions, such as liquid fluorine. It has been concluded from the present study that the short firmly embedded crystalline protuberances contribute to the coating adherence and thereby to enhanced coating wear life.

  18. SCC behavior of an Al-3. 7wt%Zn-2. 5wt%Mg alloys before and after welding in 3. 5% NaCl solution

    SciTech Connect

    Liao, C.M. )

    1993-01-01

    The behavior of stress corrosion cracking (SCC) of an overaged Al-3.7wt%Zn-2.5wt%Mg alloy including base metal, weldment, and heat-affected zone (HAZ) in 3.5% NaCl solution was investigated. This Al-Zn-Mg alloy loaded in longitudinal or long transverse direction has good SCC resistance and is maintained even after welding. Welding residual stress alone does not induce the SCC of the weldment. The result of the specially modified type 1 double cantilever beam (DCB) testing shows that the crack can be arrested by the weld metal because of the better SCC resistance of the filler metal ER5183. In addition, a specially designed type 2 DCB testing indicates that the SCC resistance of the HAZ is better than that of the base metal because of the re-overaging of the HAZ during welding.

  19. Expression profile of Wilms Tumor 1 (WT1) isoforms in undifferentiated and all-trans retinoic acid differentiated neuroblastoma cells

    PubMed Central

    Maugeri, Grazia; D'Amico, Agata Grazia; Rasà, Daniela Maria; Reitano, Rita; Saccone, Salvatore; Federico, Concetta; Parenti, Rosalba; Magro, Gaetano; D'Agata, Velia

    2016-01-01

    Wilms tumor 1 gene (WT1) is a tumor suppressor gene originally identified in nephroblastoma. It is also expressed in neuroblastoma which represents the most aggressive extracranial pediatric tumor. Many evidences have shown that neuroblastoma may undergo maturation, by transforming itself in a more differentiated tumors such as ganglioneuroblastoma and ganglioneuroma, or progressing into a highly aggressive metastatic malignancy. To date, 13 WT1 mRNA alternative splice variants have been identified. However, most of the studies have focused their attention only on isoform of ∼49 kDa. In the present study, it has been investigated the expression pattern of WT1 isoforms in an in vitro model of neuroblastoma consisting in undifferentiated or all-trans retinoic acid (RA) differentiated cells. These latter representing the less malignant phenotype of this tumor. Results have demonstrated that WT1.1-WT1.5, WT1.6-WT1.9, WT1.10 WT1.11-WT1.12 and WT1.13 isoforms are expressed in both groups of cells, but their levels are significantly increased after RA treatment. These data have also been confirmed by immunofluorescence analysis. Moreover, the inhibition of PI3K/Akt and MAPK/ERK, that represent two signalling pathway specifically involved in NB differentiation, induces an overexpression of WT1 isoforms. These data suggest that WT1 isoforms might be involved in differentiation of neuroblastic into mature ganglion cells. PMID:27014421

  20. Microstructure and Mechanical Properties of Al-8 pct Si Alloy Prepared by Direct Chill Casting Under Electromagnetic and Ultrasonic Fields

    NASA Astrophysics Data System (ADS)

    Zhang, Yubo; Jie, Jinchuan; Wu, Li; Fu, Ying; Li, Mu; Lu, Yiping; Li, Tingju

    2014-04-01

    The intermediate frequency electromagnetic field and power ultrasonic field were applied during the direct chill (DC) casting process of Al-8 pct Si alloy. The effects of different physical fields on the solidification microstructure and mechanical properties were studied. The results show that compared to the conventional casting without any treatments, refined microstructures and improved mechanical properties can be obtained when the electromagnetic or ultrasonic field is applied individually. For the case of compound fields, the electromagnetic field can increase the ultrasonic treated region, while the ultrasonic field can enhance the refinement effect of electromagnetic field. Owing to the advantages of both electromagnetic and ultrasonic fields, the microstructure obtained under the compound fields is fine and uniform, leading to a remarkable enhancement of mechanical properties. The interaction mechanism between intermediate frequency electromagnetic field and power ultrasonic field was discussed. The present study may be useful for grain refinement and improvement of mechanical properties of alloys during the DC casting process which is now widely used in industry.

  1. Effect of Boron on Carbide Coarsening at 873 K (600 °C) in 9 to 12 pct Chromium Steels

    NASA Astrophysics Data System (ADS)

    Liu, Fang; Fors, Dan H. R.; Golpayegani, Ardeshir; Andrén, Hans-Olof; Wahnström, Göran

    2012-11-01

    The addition of small amounts of boron to 9 to 12 pct chromium steels has been found to decrease their creep rate at 823 K to 923 K (550 °C to 650 °C). In this article, the behavior of boron during austenitizing, tempering, and isothermal heat treatment at 873 K (600 °C) is studied using high-resolution microscopy and microanalysis as well as using atomistic modeling. It was found that increasing the boron content from 9 to 40 ppm decreased the coarsening constant of M23C6 by a factor of almost 2. Most of the added boron was incorporated in M23C6. Atomistic modeling showed that boron diffusion in ferrite is dominated by an interstitial mechanism at 873 K (600 °C). However, the generation of vacancies when carbide precipitates dissolve may promote a distribution with substitutional boron atoms. The absence of a fast mechanism for the transition from substitutional to interstitial occupancy will make the slow substitutional boron diffusion in the matrix rate controlling for the coarsening process.

  2. Microstructure Evolution and Pinning of Boundaries by Precipitates in a 9 pct Cr Heat Resistant Steel During Creep

    NASA Astrophysics Data System (ADS)

    Dudko, Valeriy; Belyakov, Andrey; Molodov, Dmitri; Kaibyshev, Rustam

    2013-01-01

    Structural changes in a 9 pct Cr martensitic steel during a creep test at 923 K (720 °C) under the applied stress of 118 MPa were examined. The tempered martensite lath structure (TMLS) was characterized by M23C6-type carbide particles with an average size of about 110 nm and MX-type carbonitrides with a size of 40 nm. The M23C6 particles were located on the packet/block/lath boundaries, whereas the MX precipitates were distributed homogeneously throughout TMLS. TMLS in the grip portion of the crept specimen changed scarcely during the tests. In contrast, the structural changes in the gauge section of the samples were characterized by the evolution of relatively large subgrains with remarkably lowered density of interior dislocations within former martensite laths. The formation of a well-defined subgrain structure in the gauge section was accompanied by the coarsening of M23C6 carbides and precipitations of Laves phase during creep. The most pronounced structural changes occurred just at the beginning of the tertiary creep regime, which was interpreted as a result of the change in the mechanism of grain boundary pinning by precipitates.

  3. Isothermal Reduction of Oxide Scale on Hot-Rolled, Low-Carbon Steel in 10 pct H2-Ar

    NASA Astrophysics Data System (ADS)

    He, Yongquan; Jia, Tao; Li, Zhifeng; Cao, Guangming; Liu, Zhenyu; Li, Jun

    2016-08-01

    The isothermal reduction of oxide scale on hot-rolled, low-carbon steel strip in 10 pct H2-Ar mixtures in the temperature range of 673 K to 1073 K (400 °C to 800 °C) was investigated by using a thermo-gravimetric analyzer (TGA). During heating under an argon atmosphere, magnetite/iron eutectoid and proeutectoid magnetite in the oxide scale successively transformed into wüstite at a temperature above 843 K (570 °C). The kinetic plot of the isothermal reduction assumes a sigmoid shape, including induction, acceleration, and finally the decaying stage. Fitting the kinetic curve to mathematical models, the reaction at 1073 K (800 °C) and 773 K (500 °C) were determined to be controlled by phase-boundary-controlled reaction and three-dimensional growth of nuclei, respectively. The reduction product varies with temperature and itself affects the kinetics. Porous and dense iron were, respectively, obtained below and above 873 K (600 °C). A "rate-minimum" was observed at 973 K (700 °C) due to the formation of dense iron that blocks the gas diffusion. Due to the structural transformation of oxide scale during heating, the reactant depends on the heating process. However, compared with the oxide scale structure, the temperature is more important in determining the reduction kinetics at temperatures above 973 K (700 °C).

  4. Microstructure Evolution in an Advanced 9 pct Cr Martensitic Steel during Creep at 923 K (650 °C)

    NASA Astrophysics Data System (ADS)

    Fedorova, Irina; Kipelova, Alla; Belyakov, Andrey; Kaibyshev, Rustam

    2013-01-01

    Crept microstructures were examined in a 9 pct Cr martensitic steel with low carbon content. The steel was hot forged at 1323 K (1050 °C) followed by air cooling and then tempered at 1023 K (750 °C) for 3 hours. The tempered microstructure included numerous precipitates of MX-type carbonitrides and a small amount of M23C6-type carbides. Two groups of the MX-type particles were observed. The nanoscale MX-type precipitates appeared in the form of plate- and round-shaped particles. The plate-shaped MX-type particles were approximately 15 nm in the longitudinal direction and approximately 3 nm in thickness, and the round-shaped MX-type particles were 10 nm in diameter. In addition to the fine particles, the tempered martensite contained relatively coarse MX-type particles, which have a size of approximately 90 nm. The structural changes that occurred during the creep test were associated with an increase in the sizes of the lath and second-phase particles. Moreover, the creep was accompanied by appearance of Laves and Z-phase particles.

  5. High-Temperature Deformation Behavior of a Ti-6Al-7Nb Alloy in Dual-Phase (α + β) and Single-Phase (β) Regions

    NASA Astrophysics Data System (ADS)

    Pilehva, F.; Zarei-Hanzaki, A.; Moemeni, S.; Khalesian, A. R.

    2016-01-01

    The present study aimed to characterizing the microstructure evolution of a Ti-6Al-7Nb biomedical type titanium alloy during hot working through hot compression tests. The hot deformation cycles were conducted under the strain rate of 0.0025, 0.025, and 0.25 s-1 in the temperature range of 850-1150 °C where both dual-phase (α + β) and single-phase (β) regions could be accessible. The flow stress behavior of the material for the entire deformation regime was interpreted via microstructural observations. The results indicated that in the single-phase β region (1050-1150 °C), the dynamically recrystallized (DRX) grains were formed at the deformed and elongated beta grain boundaries as a necklace-like structure. The variations in the dynamically recrystallized grain size were determined to follow the Zener-Hollomon relationship where DRX grain size was decreased by reducing the temperature and increasing the strain rate. The alloy deformation characteristics in α + β region were somewhat different. During deformation in the upper α + β temperature range (e.g., 1000 °C), the β phase would accommodate most of the deformation, while α regions remained undeformed. In the lower α + β temperature range (e.g., 850-950 °C), the kinking/bending of α lamellae as well as the subsequent globularization of α layers were postulated to be responsible for the observed flow softening behavior.

  6. Evaluation of physicochemical properties of surface modified Ti6Al4V and Ti6Al7Nb alloys used for orthopedic implants.

    PubMed

    Basiaga, Marcin; Kajzer, Wojciech; Walke, Witold; Kajzer, Anita; Kaczmarek, Marcin

    2016-11-01

    The paper presents the results of selected functional properties of TiO2 layers deposited by ALD method on the surface of Ti6Al4V and Ti6Al7Nb alloys intended for implants in bone surgery. TiO2 layer was applied at the constant temperature of the ALD process at T=200°C at a variable number of cycles, which resulted in a different layer thickness. Different process cycles of 500, 1250, and 2500 were analyzed. The application of experimental methods (AFM, SEM, wettability, potentiodynamic test, EIS, scratch test, nanohardness and layer thickness) enabled to select the optimal number of cycles, and thus the thickness of the TiO2 layer of the most favorable functional properties. The obtained results clearly showed that regardless of the type of titanium substrate, the TiO2 layer applied in a 2500cycle ALD process has the best physicochemical and electrochemical properties. These properties have major impact on biocompatibility, and therefore the quality of the final product. The information obtained can be useful for manufacturers of medical devices involved in the production of implants used in reconstructive surgery of skeletal system. PMID:27524088

  7. Nonlinear relationship between the Product Consistency Test (PCT) response and the Al/B ratio in a soda-lime aluminoborosilicate glass

    NASA Astrophysics Data System (ADS)

    Farooqi, Rahmat Ullah; Hrma, Pavel

    2016-06-01

    We have investigated the effect of Al/B ratio on the Product Consistency Test (PCT) response. In an aluminoborosilicate soda-lime glass based on a modified International Simple Glass, ISG-3, the Al/B ratio varied from 0 to 0.55 (in mole fractions). In agreement with various models of the PCT response as a function of glass composition, we observed a monotonic increase of B and Na releases with decreasing Al/B mole ratio, but only when the ratio was higher than 0.05. Below this value (Al/B < 0.05), we observed a sharp decrease that we attribute to B in tetrahedral coordination.

  8. On the use of rhodamine WT for the characterization of stream hydrodynamics and transient storage

    NASA Astrophysics Data System (ADS)

    Runkel, Robert L.

    2015-08-01

    Recent advances in fluorometry have led to increased use of rhodamine WT as a tracer in streams and rivers. In light of this increased use, a review of the dye's behavior in freshwater systems is presented. Studies in the groundwater literature indicate that rhodamine WT is transported nonconservatively, with sorption removing substantial amounts of tracer mass. Column studies document a two-step breakthrough curve in which two structural isomers are chromatographically separated. Although the potential for nonconservative transport is acknowledged in the surface water literature, many studies assume that sorptive losses will not affect the characterization of physical transport processes. A literature review and modeling analysis indicates that this assumption is valid for quantification of physical properties that are based on the bulk of the tracer mass (traveltime), and invalid for the characterization of processes represented by the tracer tail (transient storage attributable to hyporheic exchange). Rhodamine WT should be considered nonconservative in the hyporheic zone due to nonconservative behavior demonstrated for similar conditions in groundwater. As such, rhodamine WT should not be used as a quantitative tracer in hyporheic zone investigations, including the study of long flow paths and the development of models describing hyporheic zone processes. Rhodamine WT may be used to qualitatively characterize storage in large systems, where there are few practical alternatives. Qualitative investigations should rely on early portions of the tracer profile, making use of the temporal resolution afforded by in situ fluorometry, while discarding later parts of the tracer profile that are adversely affected by sorption.

  9. Immunohistochemical Analysis of WT1 Antigen Expression in Various Solid Cancer Cells.

    PubMed

    Naitoh, Keiko; Kamigaki, Takashi; Matsuda, Eriko; Ibe, Hiroshi; Okada, Sachiko; Oguma, Eri; Kinoshita, Yoshihiro; Takimoto, Rishu; Makita, Kaori; Ogasawara, Shun; Goto, Shigenori

    2016-07-01

    For a peptide-pulsed dendritic cell (DC) vaccine to work effectively in cancer treatment, it is significant that the target protein is expressed in cancer cells. Wilms' tumor 1 (WT1) has been identified as a molecular target for immune cell therapy of cancer. We evaluated the protein expression levels of WT1 in various solid tumors, as well as mucin 1 (MUC1) or major histocompatibility complex (MHC) class l molecules. Seven hundred and thirty-eight patients whose tissue samples were examined by immunohistochemical analysis agreed to undergo DC vaccine therapy. The positive staining of WT1 in tumor cells was observed in 25.3% of patients, with only 8.5% of them showing moderate to strong expression; moreover, WT1 tended to localize in the nucleus and cytoplasm. A positive staining of tumor cells by an anti-MHC class l monoclonal antibody was observed in 98.6% and by an anti-MUC1 monoclonal antibody in 76.8% of the patients. In relation to the application of cancer-specific immunotherapy, these findings provide useful information for determining the efficacy of MUC1- and WT1-targeted therapy. PMID:27354645

  10. Reprogramming of Sertoli cells to fetal-like Leydig cells by Wt1 ablation

    PubMed Central

    Zhang, Lianjun; Chen, Min; Wen, Qing; Li, Yaqiong; Wang, Yaqing; Wang, Yanbo; Qin, Yan; Cui, Xiuhong; Yang, Lin; Huff, Vicki; Gao, Fei

    2015-01-01

    Sertoli and Leydig cells, the two major somatic cell types in the testis, have different morphologies and functions. Both are essential for gonad development and spermatogenesis. However, whether these cells are derived from the same progenitor cells and the mechanism regulating the differentiation between these two cell types during gonad development remains unclear. A previous study showed that overactivation of Ctnnb1 (cadherin-associated protein, beta 1) in Sertoli cells resulted in Sertoli cell tumors. Surprisingly, in the present study, we found that simultaneous deletion of Wilms’ Tumor Gene 1 (Wt1) and overactivation of Ctnnb1 in Sertoli cells led to Leydig cell-like tumor development. Lineage tracing experiments revealed that the Leydig-like tumor cells were derived from Sertoli cells. Further studies confirmed that Wt1 is required for the maintenance of the Sertoli cell lineage and that deletion of Wt1 resulted in the reprogramming of Sertoli cells to Leydig cells. Consistent with this interpretation, overexpression of Wt1 in Leydig cells led to the up-regulation of Sertoli cell-specific gene expression and the down-regulation of steroidogenic gene expression. These results demonstrate that the distinction between Sertoli cells and Leydig cells is regulated by Wt1, implying that these two cell types most likely originate from the same progenitor cells. This study thus provides a novel concept for somatic cell fate determination in testis development that may also represent an etiology of male infertility in human patients. PMID:25775596

  11. Observation of > 5 wt % zinc at the Kimberley outcrop, Gale crater, Mars

    NASA Astrophysics Data System (ADS)

    Lasue, J.; Clegg, S. M.; Forni, O.; Cousin, A.; Wiens, R. C.; Lanza, N.; Mangold, N.; Le Deit, L.; Gasnault, O.; Maurice, S.; Berger, J. A.; Stack, K.; Blaney, D.; Fabre, C.; Goetz, W.; Johnson, J.; Le Mouélic, S.; Nachon, M.; Payré, V.; Rapin, W.; Sumner, D. Y.

    2016-03-01

    Zinc-enriched targets have been detected at the Kimberley formation, Gale crater, Mars, using the Chemistry Camera (ChemCam) instrument. The Zn content is analyzed with a univariate calibration based on the 481.2 nm emission line. The limit of quantification for ZnO is 3 wt % (at 95% confidence level) and 1 wt % (at 68% confidence level). The limit of detection is shown to be around 0.5 wt %. As of sol 950, 12 targets on Mars present high ZnO content ranging from 1.0 wt % to 8.4 wt % (Yarrada, sol 628). Those Zn-enriched targets are almost entirely located at the Dillinger member of the Kimberley formation, where high Mn and alkali contents were also detected, probably in different phases. Zn enrichment does not depend on the textures of the rocks (coarse-grained sandstones, pebbly conglomerates, and resistant fins). The lack of sulfur enhancement suggests that Zn is not present in the sphalerite phase. Zn appears somewhat correlated with Na2O and the ChemCam hydration index, suggesting that it could be in an amorphous clay phase (such as sauconite). On Earth, such an enrichment would be consistent with a supergene alteration of a sphalerite gossan cap in a primary siliciclastic bedrock or a possible hypogene nonsulfide zinc deposition where Zn, Fe, Mn would have been transported in a reduced sulfur-poor fluid and precipitated rapidly in the form of oxides.

  12. 20 CFR 645.215 - What must a WtW operating entity that serves noncustodial parent participants do?

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 20 Employees' Benefits 3 2014-04-01 2014-04-01 false What must a WtW operating entity that serves... Administrative Requirements § 645.215 What must a WtW operating entity that serves noncustodial parent... noncustodial parents eligible under § 645.212(c)(2)(i) and that also provides WtW services to...

  13. 20 CFR 645.215 - What must a WtW operating entity that serves noncustodial parent participants do?

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 20 Employees' Benefits 3 2013-04-01 2013-04-01 false What must a WtW operating entity that serves... Administrative Requirements § 645.215 What must a WtW operating entity that serves noncustodial parent... noncustodial parents eligible under § 645.212(c)(2)(i) and that also provides WtW services to...

  14. 20 CFR 645.215 - What must a WtW operating entity that serves noncustodial parent participants do?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 20 Employees' Benefits 3 2011-04-01 2011-04-01 false What must a WtW operating entity that serves... Administrative Requirements § 645.215 What must a WtW operating entity that serves noncustodial parent... noncustodial parents eligible under § 645.212(c)(2)(i) and that also provides WtW services to...

  15. 20 CFR 645.215 - What must a WtW operating entity that serves noncustodial parent participants do?

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 20 Employees' Benefits 3 2012-04-01 2012-04-01 false What must a WtW operating entity that serves... Administrative Requirements § 645.215 What must a WtW operating entity that serves noncustodial parent... noncustodial parents eligible under § 645.212(c)(2)(i) and that also provides WtW services to...

  16. Immune responses to WT1 in patients with AML or MDS after chemotherapy and allogeneic stem cell transplantation.

    PubMed

    Casalegno-Garduño, Rosaely; Schmitt, Anita; Spitschak, Alf; Greiner, Jochen; Wang, Lei; Hilgendorf, Inken; Hirt, Carsten; Ho, Anthony D; Freund, Mathias; Schmitt, Michael

    2016-04-01

    Wilms' tumor gene 1 (WT1) is overexpressed in leukemia and WT1-derived CD8(+) T-cell epitopes for immunotherapies targeting WT1 have been defined. Here, we analyzed expression of WT1 in 226 peripheral blood and bone marrow samples from patients with acute myeloid leukemia or myelodysplastic syndrome (AML/MDS) before and after allogeneic stem cell transplantation (SCT). Transcripts were assessed by quantitative polymerase chain reaction, and WT1-specific CD8+ cytotoxic T cells (CTL) were monitored by tetramer staining and enzyme-linked immunospot (ELISPOT) assays. Reduction of WT1 levels correlated with a longer survival (p < 0.01). Increment of WT1 transcripts eventually resulted in relapse and subsequent death of the patients. In patients with longer survival and continuous complete remission (cCR) after SCT, higher and enduring frequencies of WT1-specific CTL than in patients developing a relapse were detected. These cells were effector T cells secreting interferon gamma and granzyme B. In summary, WT1 is a suitable marker for the detection of minimal residual disease after SCT or chemotherapy. A rising WT1 signal correlated with a dismal prognosis of the patients. WT1-specific CD8(+) T cells might contribute to the maintenance of a cCR. Targeting WT-1 by peptide/protein vaccination as well as adoptive transfer of genetically modified T cells are future options in the individualized therapy for AML/MDS patients. PMID:26519872

  17. Effect of thermal conditions and alloying constituents (Ni, Cr) on macrosegregation in continuously cast high-carbon (0.8 Pct), low-alloy steel

    NASA Astrophysics Data System (ADS)

    Shah, Nitin A.; Moore, John J.

    1989-12-01

    The aim of this study was to investigate the influences of heat transfer, thermal gradient, solidification rate, and the addition of up to 1 pct Ni and 1 pct Cr on the solidification and macrosegregation of high-carbon (0.8 pct), low-alloy steel. Sixteen 13.6-kg laboratory ingots were horizontally and unidirectionally cast in a static moll, fitted on one face with a water-cooled copper chill to simulate a continuous casting mold. Thermocouples, placed in the chill and the mold, were used to calculate heat flux, thermal gradient, and solidification rate. The ingots were examined with respect to macro- and microstructures, distribution of phases, dendrite arm spacing, and solute element distribution. The extent of macrosegregation of carbon and sulfur was determined by wet chemical analysis of drillings, and a TANDEM VAN DE GRAAFF accelerator was used for A1, Si, P, V, S, C, Mn, Ni, and Cu. The extent of macrosegregation of these elements was correlated with heat transfer and thermodynamic distribution coefficient data.

  18. Crossed-Wire Laser Microwelding of Pt-10 Pct Ir to 316 Low-Carbon Vacuum Melted Stainless Steel: Part I. Mechanism of Joint Formation

    NASA Astrophysics Data System (ADS)

    Zou, G. S.; Huang, Y. D.; Pequegnat, A.; Li, X. G.; Khan, M. I.; Zhou, Y.

    2012-04-01

    The excellent biocompatibility and corrosion properties of Pt alloys and 316 low-carbon vacuum melted (LVM) stainless steel (SS) make them attractive for biomedical applications. With the increasing complexity of medical devices and in order to lower costs, the challenge of joining dissimilar materials arises. In this study, laser microwelding (LMW) of crossed Pt-10 pct Ir to 316 LVM SS wires was performed and the weldability of these materials was determined. The joint geometry, joining mechanism, joint breaking force (JBF), and fracture modes were investigated using optical microscopy, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and microtensile testing. It was shown that the mechanisms of joint formation transitioned from (1) brazing, (2) a combination of brazing and fusion welding, and (3) fusion welding with increasing pulsed laser energy. The joints demonstrated various tensile failure modes including (1) interfacial failure below a peak power of 0.24 kW, (2) partial interfacial failure that propagated into the Pt-Ir wire, (3) failure in the Pt-Ir wire, and (4) failure in the SS wire due to porosity and severe undercutting caused by overwelding. During this study, the optimal laser peak power range was identified to produce joints with good joint geometry and 90 pct of the tensile strength of the Pt-10 pct Ir wire.

  19. Modeling and forecasting of KLCI weekly return using WT-ANN integrated model

    NASA Astrophysics Data System (ADS)

    Liew, Wei-Thong; Liong, Choong-Yeun; Hussain, Saiful Izzuan; Isa, Zaidi

    2013-04-01

    The forecasting of weekly return is one of the most challenging tasks in investment since the time series are volatile and non-stationary. In this study, an integrated model of wavelet transform and artificial neural network, WT-ANN is studied for modeling and forecasting of KLCI weekly return. First, the WT is applied to decompose the weekly return time series in order to eliminate noise. Then, a mathematical model of the time series is constructed using the ANN. The performance of the suggested model will be evaluated by root mean squared error (RMSE), mean absolute error (MAE), mean absolute percentage error (MAPE). The result shows that the WT-ANN model can be considered as a feasible and powerful model for time series modeling and prediction.

  20. Acute Multiple Organ Failure in Adult Mice Deleted for the Developmental Regulator Wt1

    PubMed Central

    Chau, You-Ying; Brownstein, David; Mjoseng, Heidi; Lee, Wen-Chin; Buza-Vidas, Natalija; Nerlov, Claus; Jacobsen, Sten Eirik; Perry, Paul; Berry, Rachel; Thornburn, Anna; Sexton, David; Morton, Nik; Hohenstein, Peter; Freyer, Elisabeth; Samuel, Kay; van't Hof, Rob; Hastie, Nicholas

    2011-01-01

    There is much interest in the mechanisms that regulate adult tissue homeostasis and their relationship to processes governing foetal development. Mice deleted for the Wilms' tumour gene, Wt1, lack kidneys, gonads, and spleen and die at mid-gestation due to defective coronary vasculature. Wt1 is vital for maintaining the mesenchymal–epithelial balance in these tissues and is required for the epithelial-to-mesenchyme transition (EMT) that generates coronary vascular progenitors. Although Wt1 is only expressed in rare cell populations in adults including glomerular podocytes, 1% of bone marrow cells, and mesothelium, we hypothesised that this might be important for homeostasis of adult tissues; hence, we deleted the gene ubiquitously in young and adult mice. Within just a few days, the mice suffered glomerulosclerosis, atrophy of the exocrine pancreas and spleen, severe reduction in bone and fat, and failure of erythropoiesis. FACS and culture experiments showed that Wt1 has an intrinsic role in both haematopoietic and mesenchymal stem cell lineages and suggest that defects within these contribute to the phenotypes we observe. We propose that glomerulosclerosis arises in part through down regulation of nephrin, a known Wt1 target gene. Protein profiling in mutant serum showed that there was no systemic inflammatory or nutritional response in the mutant mice. However, there was a dramatic reduction in circulating IGF-1 levels, which is likely to contribute to the bone and fat phenotypes. The reduction of IGF-1 did not result from a decrease in circulating GH, and there is no apparent pathology of the pituitary and adrenal glands. These findings 1) suggest that Wt1 is a major regulator of the homeostasis of some adult tissues, through both local and systemic actions; 2) highlight the differences between foetal and adult tissue regulation; 3) point to the importance of adult mesenchyme in tissue turnover. PMID:22216009

  1. H2 production from simulated coal syngas containing H2S in multi-tubular Pd and 80 wt% Pd-20 wt% Cu membrane reactors

    SciTech Connect

    Iyoha, O.; Enick, R.M.; Killmeyer, R.P.; Howard, B.H.; Ciocco, M.V.; Morreale, B.

    2007-12-01

    99.7% conversion of CO in a simulated syngas feed containing 53% CO, 35% H2 and 12% CO2 was achieved via the water–gas shift (WGS) reaction in a counter-current Pd multi-tube membrane reactor (MR) at 1173 K and 2 s residence time. This conversion is significantly greater than the 32% equilibrium conversion associated with a conventional (non-membrane) reactor primarily due to the high rate of H2 extraction from the reaction zone through the Pd membranes at elevated temperatures. Furthermore, nearly complete H2 recovery was attained in the permeate, resulting in the simultaneous production of a high-pressure CO2 (>99%) retentate stream after condensation of the steam. When Pd80 wt%Cu tubes were used in the reactor, a significantly lower CO conversion of 68% was attained at comparable residence times, probably due to the lower H2 permeance of the alloy. When H2S was added to the syngas feed and the H2S-to-H2 ratio was maintained below the threshold required for thermodynamically stable sulfides to form, the Pd and Pd80 wt%Cu MRs retained their mechanical integrity and H2 selectivity, but a precipitous drop in CO conversion was observed due to deactivation of the catalytic surface. The Pd and Pd80 wt%Cu MRs were observed to fail within minutes after increasing the H2S-to-H2 ratio to levels above that expected for thermodynamically stable sulfides to form, as evidenced by rupturing of the membrane tubes. SEM–EDS analyses of the membranes suggested that at high H2S-to-H2 ratios, the H2S compromised the mechanical integrity of the MRs by preferentially attacking the grain boundary region.

  2. Behavior of 12 wt% TRIGA fuel after many years of operation

    SciTech Connect

    Levine, S.H.; Boyle, P.

    1997-12-01

    In July 1972, six 12 wt% Uzr-H TRIGA fuel elements were loaded into the B-ring, the innermost ring, of the Penn State Breazeale Research Reactor (PSBR) to increase its k{sub eff}. Of these initial six fuel elements, three remain in the core, and the other three fuel elements had to be removed from the core. The purpose of this summary is to present operational-type data on the 12 wt% Uzr-H TRIGA fuel elements that have been in the PSBR during the past 25 yr and to postulate reasons for the structural change of those removed from the core.

  3. Measurement of ground water velocity using Rhodamine WT dye near Sheffield, Illinois

    USGS Publications Warehouse

    Garklavs, George; Toler, L.G.

    1985-01-01

    Ground-water flow velocity was estimated in a tract of land adjacent to a low-level radioactive-waste disposal site near Sheffield, Illinois, by measuring the time-of-travel between two wells spaced 110 feet apart. Rhodamine WT dye was the principal tracer used in the test. The leading edge and peak concentrations of Rhodamine WT were well defined. A ground-water velocity of 6.9 feet per day (2,500 feet per year) was computed from the arrival time of the leading edge of the tracer cloud. (USGS)

  4. Characterization of Ti6Al7Nb alloy foams surface treated in aqueous NaOH and CaCl2 solutions.

    PubMed

    Bütev, Ezgi; Esen, Ziya; Bor, Şakir

    2016-07-01

    Ti6Al7Nb alloy foams having 53-73% porosity were manufactured via evaporation of magnesium space holders. A bioactive 1µm thick sodium hydrogel titanate layer, NaxH2-xTiyO2y+1, formed after 5M NaOH treatment, was converted to crystalline sodium titanate, Na2TiyO2y+1, as a result of post-heat treatment. On the other hand, subsequent CaCl2 treatment of NaOH treated specimens induced calcium titanate formation. However, heat treatment of NaOH-CaCl2 treated specimens led to the loss of calcium and disappearance of the titanate phase. All of the aforementioned surface treatments reduced yield strengths due to the oxidation of the cell walls of the foams, while elastic moduli remained mostly unchanged. Accordingly, equiaxed dimples seen on the fracture surfaces of as-manufactured foams turned into relatively flat and featureless fracture surfaces after surface treatments. On the other hand, Ca- and Na-rich coating preserved their mechanical stabilities and did not spall during fracture. The relation between mechanical properties of foams and macro-porosity fraction were found to obey a power law. The foams with 63 and 73% porosity met the desired biocompatibility requirements with fully open pore structures and elastic moduli similar to that of bone. In vitro tests conducted in simulated body fluid (SBF) showed that NaOH-heat treated surfaces exhibit the highest bioactivity and allow the formation of Ca-P rich phases having Ca/P ratio of 1.3 to form within 5 days. Although Ca-P rich phases formed only after 15 days on NaOH-CaCl2 treated specimens, the Ca/P ratio was closer to that of apatite found in bone. PMID:26807769

  5. Transcriptional regulation of the human Wilms' tumor gene (WT1). Cell type-specific enhancer and promiscuous promoter.

    PubMed

    Fraizer, G C; Wu, Y J; Hewitt, S M; Maity, T; Ton, C C; Huff, V; Saunders, G F

    1994-03-25

    The Wilms' tumor gene, WT1, is expressed in few tissues, mainly the developing kidney, genitourinary system, and mesothelium, and in immature hematopoietic cells. To develop an understanding of the role of WT1 in development and tumorigenesis, we have identified transcriptional regulatory elements that function in transient reporter gene constructs transfected into kidney and hematopoietic cell lines. We found three transcription start sites of the WT1 gene and have identified an essential promoter region by deletion analysis. The WT1 promoter is a member of the GC-rich, TATA-less, and CCAAT-less class of polymerase II promoters. Whereas the WT1 promoter is similar to other tumor suppressor gene promoters, the WT1 expression pattern (unlike Rb and p53) is tissue-restricted. The WT1 GC-rich promoter is promiscuous, functioning in all cell lines tested, independent of WT1 expression. This finding suggests that the promoter is not tissue-specific, but that tissue-specific expression of WT1 is modulated by additional regulatory elements. Indeed, we have identified a transcriptional enhancer located 3' of the WT1 gene > 50 kilobases downstream from the promoter. This orientation-independent enhancer increases the basal transcription rate of the WT1 promoter in the human erythroleukemia cell line K562, but not in any of the other cell lines tested. PMID:8132626

  6. WT1 interacts with the splicing protein RBM4 and regulates its ability to modulate alternative splicing in vivo

    SciTech Connect

    Markus, M. Andrea; Heinrich, Bettina; Raitskin, Oleg; Adams, David J.; Mangs, Helena; Goy, Christine; Ladomery, Michael; Sperling, Ruth; Stamm, Stefan; Morris, Brian J. . E-mail: brianm@medsci.usyd.edu.au

    2006-10-15

    Wilm's tumor protein 1 (WT1), a protein implicated in various cancers and developmental disorders, consists of two major isoforms: WT1(-KTS), a transcription factor, and WT1(+KTS), a post-transcriptional regulator that binds to RNA and can interact with splicing components. Here we show that WT1 interacts with the novel splicing regulator RBM4. Each protein was found to colocalize in nuclear speckles and to cosediment with supraspliceosomes in glycerol gradients. RBM4 conferred dose-dependent and cell-specific regulation of alternative splicing of pre-mRNAs transcribed from several reporter genes. We found that overexpressed WT1(+KTS) abrogated this effect of RBM4 on splice-site selection, whereas WT1(-KTS) did not. We conclude that the (+KTS) form of WT1 is able to inhibit the effect of RBM4 on alternative splicing.

  7. Effect of Mushy State Rolling on the Microstructure, Microhardness, and Microtexture in Al-4.5wt.%Cu-5wt.%TiB2 In Situ Composite

    NASA Astrophysics Data System (ADS)

    Mandal, Monalisa; Mitra, Rahul

    2016-07-01

    Al-4.5wt.%Cu-5wt.%TiB2 in situ composite, fabricated by stir casting through a mixed salt reaction route process, needs further processing to exclude casting defects. Mushy state rolling has been developed as an easy and energy-efficient method for microstructural refinement and improvement in mechanical properties. It has been carried out at 621°C and 632°C with 20 vol.% and 30 vol.% of liquid, respectively, for up to 5% reduction in thickness. Mushy state rolling of the as-cast composite gives rise to a bimodal microstructure, which consists of very fine equiaxed grains adjacent to the rolled surface and comparatively larger elongated grains away from the rolled surface of the sample. Microhardness of the mushy state rolled sample has been observed to decrease gradually from edge to center of the rolled sample. The presence of the dislocation tangles and subgrains formed by dynamic recovery within solid-state deformed elongated grains and formation of recrystallized grains just adjacent to the second-phase particles have been examined with the help of electron backscattered diffraction and transmission electron microscopy analysis.

  8. Effect of Mushy State Rolling on the Microstructure, Microhardness, and Microtexture in Al-4.5wt.%Cu-5wt.%TiB2 In Situ Composite

    NASA Astrophysics Data System (ADS)

    Mandal, Monalisa; Mitra, Rahul

    2016-04-01

    Al-4.5wt.%Cu-5wt.%TiB2 in situ composite, fabricated by stir casting through a mixed salt reaction route process, needs further processing to exclude casting defects. Mushy state rolling has been developed as an easy and energy-efficient method for microstructural refinement and improvement in mechanical properties. It has been carried out at 621°C and 632°C with 20 vol.% and 30 vol.% of liquid, respectively, for up to 5% reduction in thickness. Mushy state rolling of the as-cast composite gives rise to a bimodal microstructure, which consists of very fine equiaxed grains adjacent to the rolled surface and comparatively larger elongated grains away from the rolled surface of the sample. Microhardness of the mushy state rolled sample has been observed to decrease gradually from edge to center of the rolled sample. The presence of the dislocation tangles and subgrains formed by dynamic recovery within solid-state deformed elongated grains and formation of recrystallized grains just adjacent to the second-phase particles have been examined with the help of electron backscattered diffraction and transmission electron microscopy analysis.

  9. Effect of rolling technologies on the properties of Pb-0.06wt%Ca-1.2wt%Sn alloy anodes during copper electrowinning

    NASA Astrophysics Data System (ADS)

    Yang, Jian; Chen, Bu-ming; Hang, Hui; Guo, Zhong-cheng; Wang, Shuai

    2015-11-01

    The objective of this work was to study the effect of different rolling technologies on the properties of Pb-0.06wt%Ca-1.2wt%Sn anodes during copper electrowinning and to determine the relationship between the properties of the anodes and rolling techniques during copper electrowinning. The anode process was investigated via anodic polarization curves, cyclic voltammetry curves, electrochemical impedance spectra, and corrosion tests. The microscopic morphology and phase composition of the anodic oxide layers were observed by scanning electron microscopy and X-ray diffraction, respectively. Observable variations in the electrocatalytic activity and reaction kinetics of anodes during electrowinning indicated that the electrochemical behavior of the anodes was strongly affected by the rolling technology. An increase in the rolling number tended to decrease the oxygen evolution overpotential and the corrosion rate of the anodes. These trends are contrary to that of the apparent exchange current density. Furthermore, the intensities of diffraction peaks associated with PbO, PbOx, and α-PbO2 tended to increase with increasing rolling number. In addition, the rolled anodes exhibited a more uniform microstructure. Compared with one-way rolled anodes, the eight-time cross rolled anodes exhibited better electrocatalytic activity and improved corrosion resistance.

  10. Structural characterization of sputter-deposited SS304+x aluminum (x = 0, 4, 7 and 10 wt.%) coatings and mechanically milled titanium, zirconium and hafnium powders

    NASA Astrophysics Data System (ADS)

    Seelam, Uma Maheswara Rao

    Study of the metastable phases obtained by non-equilibrium processing techniques has come a long way during the past five decades. New metastable phases have often given new perspectives to the research on synthesis of novel materials systems. Metastable materials produced by two non-equilibrium processing methods were studied for this dissertation---304-type austenitic stainless steel (SS304 or Fe-18Cr-8Ni)+aluminum coatings produced by plasma enhanced magnetron sputter-deposition (PEMS) and nanocrystalline Ti, Zr and Hf powders processed by mechanical milling (MM). The objective of the study was to understand the crystallographic and microstructural aspects of these materials. Four SS304+Al coatings with a nominal Al percentages of 0, 4, 7 and 10 wt.% in the coatings were deposited on an SS304 substrate by PEMS using SS304 and Al targets. The as-deposited coatings were characterized by x-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and three-dimensional atom probe microscopy (3DAP). Surface morphology and chemical analysis were studied by SEM. Phase identification was carried out by XRD and TEM. The microstructural features of all the coatings, as observed in the TEM, consisted of columnar grains with the columnar grain width (a measure of grain size) increasing with an increase in the Al content. The coatings had grains with average grain sizes of about 100, 290, 320 and 980 nm, respectively for 0, 4, 7 and 10 wt.% Al. The observed grain structures and increase in grain size were related to substrate temperature during deposition. XRD results indicated that the Al-free coating consisted of the non-equilibrium ferrite and sigma phases. In the 4Al, 7Al and 10Al coatings, equilibrium ferrite and B2 phases were observed but no sigma phase was found. In 10Al coating, we were able to demonstrate experimentally using 3DAP studies that NiAl phase formation is preferred over the FeAl phase at nano scale. During

  11. All-Fiber Optical Faraday Mirror Using 56-wt%-Terbium-Doped Fiber

    SciTech Connect

    Sun, L.; Jiang, S.; Marciante, J.R.

    2010-06-22

    An all-fiber optical Faraday mirror that consists of a fiber Faraday rotator and a fiber Bragg grating is demonstrated. The fiber Faraday rotator uses a 21-cm-long section of 56-wt%-terbium-doped silicate fiber. The polarization state of the reflected light is rotated 89 degrees +/- 2 degrees with a 16-dB polarization extinction ratio.

  12. 50 CFR Table 30 to Part 679 - Rockfish Program Retainable Percentages (in round wt. equivalent)

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 50 Wildlife and Fisheries 13 2013-10-01 2013-10-01 false Rockfish Program Retainable Percentages (in round wt. equivalent) 30 Table 30 to Part 679 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE (CONTINUED) FISHERIES OF THE EXCLUSIVE ECONOMIC ZONE OFF ALASKA...

  13. 50 CFR Table 30 to Part 679 - Rockfish Program Retainable Percentages (in round wt. equivalent)

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 50 Wildlife and Fisheries 13 2014-10-01 2014-10-01 false Rockfish Program Retainable Percentages (in round wt. equivalent) 30 Table 30 to Part 679 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE (CONTINUED) FISHERIES OF THE EXCLUSIVE ECONOMIC ZONE OFF ALASKA...

  14. 50 CFR Table 30 to Part 679 - Rockfish Program Retainable Percentages (in round wt. equivalent)

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 50 Wildlife and Fisheries 13 2012-10-01 2012-10-01 false Rockfish Program Retainable Percentages (in round wt. equivalent) 30 Table 30 to Part 679 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE (CONTINUED) FISHERIES OF THE EXCLUSIVE ECONOMIC ZONE OFF ALASKA...

  15. 50 CFR Table 30 to Part 679 - Rockfish Program Retainable Percentages (in round wt. equivalent)

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false Rockfish Program Retainable Percentages (in round wt. equivalent) 30 Table 30 to Part 679 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE (CONTINUED) FISHERIES OF THE EXCLUSIVE ECONOMIC ZONE OFF ALASKA...

  16. Hominin diversity in the Middle Pliocene of eastern Africa: the maxilla of KNM-WT 40000.

    PubMed

    Spoor, Fred; Leakey, Meave G; Leakey, Louise N

    2010-10-27

    The 3.5-Myr-old hominin cranium KNM-WT 40000 from Lomekwi, west of Lake Turkana, has been assigned to a new hominin genus and species, Kenyanthropus platyops, on the basis of a unique combination of derived facial and primitive neurocranial features. Central to the diagnosis of K. platyops is the morphology of the maxilla, characterized by a flat and relatively orthognathic subnasal region, anteriorly placed zygomatic processes and small molars. To study this morphology in more detail, we compare the maxillae of African Plio-Pleistocene hominin fossils and samples of modern humans, chimpanzees and gorillas, using conventional and geometric morphometric methods. Computed tomography scans and detailed preparation of the KNM-WT 40000 maxilla enable comprehensive assessment of post-mortem changes, so that landmark data characterizing the morphology can be corrected for distortion. Based on a substantially larger comparative sample than previously available, the results of statistical analyses show that KNM-WT 40000 is indeed significantly different from and falls outside the known range of variation of species of Australopithecus and Paranthropus, contemporary Australopithecus afarensis in particular. These results support the attribution of KNM-WT 40000 to a separate species and the notion that hominin taxonomic diversity in Africa extends back well into the Middle Pliocene. PMID:20855311

  17. Wt-1 Expression Linked to Nitric Oxide Availability during Neonatal Obstructive Nephropathy

    PubMed Central

    Mazzei, Luciana; Manucha, Walter

    2013-01-01

    The wt-1 gene encodes a zinc finger DNA-binding protein that acts as a transcriptional activator or repressor depending on the cellular or chromosomal context. The wt-1 regulates the expression of a large number of genes that have a critical role in kidney development. Congenital obstructive nephropathy disrupts normal renal development and causes chronic progressive interstitial fibrosis, which contributes to renal growth arrest, ultimately leading to chronic renal failure. Wt-1 is downregulated during congenital obstructive nephropathy, leading to apoptosis. Of great interest, nitric oxide bioavailability associated with heat shock protein 70 (Hsp70) interaction may modulate wt-1 mRNA expression, preventing obstruction-induced cell death during neonatal unilateral ureteral obstruction. Moreover, recent genetic researches have allowed characterization of many of the complex interactions among the individual components cited, but the realization of new biochemical, molecular, and functional experiments as proposed in our and other research labs allows us to establish a deeper level of commitment among proteins involved and the potential pathogenic consequences of their imbalance. PMID:24288526

  18. 45 CFR 260.32 - What does the term “WtW cash assistance” mean?

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 45 Public Welfare 2 2010-10-01 2010-10-01 false What does the term âWtW cash assistanceâ mean? 260.32 Section 260.32 Public Welfare Regulations Relating to Public Welfare OFFICE OF FAMILY ASSISTANCE (ASSISTANCE PROGRAMS), ADMINISTRATION FOR CHILDREN AND FAMILIES, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL TEMPORARY ASSISTANCE FOR...

  19. ADAMS/WT advanced development - version 1.4 and beyond

    SciTech Connect

    Elliott, A.S.; Depauw, T.R.

    1996-12-31

    ADAMS/WT is an wind-turbine-specific shell for the general-purpose mechanical system simulation package ADAMS5. It was developed under the guidance of the National Renewable Energy Laboratory to give engineers and analysts in the wind turbine community access to the analytical power of ADAMS, without having to become expert in its particular technology. The 1.4 version of ADAMS/WT is the most recent upgrade to the package, incorporating the most up-to-date version of the AeroDyn aerodynamic forcing subroutines from the University of Utah. It is also the first version to be made available on the Windows/NT platform. In version 1.4, ADAMS/WT has been significantly improved throughout and runs much faster. Automatic generation of standardized output has been added. The documentation has been extensively augmented with more detailed descriptions, more figures and more examples. ADAMS/WT remains the most powerful analytical tool available for horizontal-axis wind turbine development. 10 figs.

  20. Review of experimental additions of rhodamine wt dye into reactive aquatic environments

    SciTech Connect

    Bencala, K.E.; Zellweger, G.W. )

    1988-09-01

    The fluorescent dye rhodamine WT is routinely used in hydrologic studies. It is also being used in field studies of the potential addition or loss of other chemical components to aquatic systems; for example, the determination of atmospheric oxygen transfer to streams or the study of solute transport in an acidic and metal-rich stream. Although rhodamine WT is considered appropriate environmentally as a tracer, toxicological concerns have been raised as the result of laboratory experiments. Smart (1984) placed these concerns in the environmental perspective. Steinheimer and Johnson (1986) have shown that an environmental hazard does not exist when following customary dye-study practices. Additional work by Abidi et al (1986) also has lessened the concerns regarding potential environmental hazards. Because this dye is generally considered effective and nonhazardous, it has been tested in environments in which its stability may be questioned a priori. An appreciable body of knowledge is now growing regarding the chemical fate of rhodamine WT dye in aquatic systems. Smart and Laidlaw (1977) previously presented an extensive evaluation of fluorescent dye properties in natural waters. Their survey included consideration of the impact of temperature, pH, salinity, chlorine, photochemical decay, chemical decay, and biodegradation. This presentation is a review of selected recent evaluations of rhodamine WT in reactive environments that were acidic or that presented significant opportunity for dye sorption onto solids.

  1. Hominin diversity in the Middle Pliocene of eastern Africa: the maxilla of KNM-WT 40000

    PubMed Central

    Spoor, Fred; Leakey, Meave G.; Leakey, Louise N.

    2010-01-01

    The 3.5-Myr-old hominin cranium KNM-WT 40000 from Lomekwi, west of Lake Turkana, has been assigned to a new hominin genus and species, Kenyanthropus platyops, on the basis of a unique combination of derived facial and primitive neurocranial features. Central to the diagnosis of K. platyops is the morphology of the maxilla, characterized by a flat and relatively orthognathic subnasal region, anteriorly placed zygomatic processes and small molars. To study this morphology in more detail, we compare the maxillae of African Plio-Pleistocene hominin fossils and samples of modern humans, chimpanzees and gorillas, using conventional and geometric morphometric methods. Computed tomography scans and detailed preparation of the KNM-WT 40000 maxilla enable comprehensive assessment of post-mortem changes, so that landmark data characterizing the morphology can be corrected for distortion. Based on a substantially larger comparative sample than previously available, the results of statistical analyses show that KNM-WT 40000 is indeed significantly different from and falls outside the known range of variation of species of Australopithecus and Paranthropus, contemporary Australopithecus afarensis in particular. These results support the attribution of KNM-WT 40000 to a separate species and the notion that hominin taxonomic diversity in Africa extends back well into the Middle Pliocene. PMID:20855311

  2. Novel WT1 Missense Mutations in Han Chinese Women with Premature Ovarian Failure.

    PubMed

    Wang, Huidan; Li, Guangyu; Zhang, Jun; Gao, Fei; Li, Weiping; Qin, Yingying; Chen, Zi-Jiang

    2015-01-01

    Premature ovarian failure (POF) is a heterogeneous disease. Though dozens of candidate genes have been identified for the genetic etiology of POF, it is largely unexplained in majority of patients. Recently, Wt1(+/R394W) mice was found to present POF-like phenotype, which indicates that WT1 might be a plausible candidate gene for non-syndromic POF. The coding region of WT1 gene was screened in 384 patients with POF and 6 novel variations were identified, including two missense mutations (p. Pro126Ser in exon1 and p. Arg370His in exon7) and four intronic variants (c.647-27C > T, c.647-13G > C, c.647-13G > A in intron1 and c.950 + 14T > C in intron 4). In vitro experiments showed that both mutant p. Pro126Ser and p. Arg370His repressed the expression of Amh and Cdh1, and induced the expression of Fshr and Cyp19 in mRNA level (P < 0.05). The expression changes of AMH, FSHR, CYP19 and CDH1 were confirmed by western blot. These genes (AMH, FSHR, CYP19 and CDH1) are required for granular cells (GCs) proliferation, differentiation and oocyte-GCs interaction. The novel mutant p. P126S and p. R370H in the WT1 gene potentially impaired GCs differentiation and oocyte-GCs interaction, which might result in loss of follicles prematurely. Therefore, WT1 is a plausible causal gene for POF. PMID:26358501

  3. Novel WT1 Missense Mutations in Han Chinese Women with Premature Ovarian Failure

    PubMed Central

    Wang, Huidan; Li, Guangyu; Zhang, Jun; Gao, Fei; Li, Weiping; Qin, Yingying; Chen, Zi-Jiang

    2015-01-01

    Premature ovarian failure (POF) is a heterogeneous disease. Though dozens of candidate genes have been identified for the genetic etiology of POF, it is largely unexplained in majority of patients. Recently, Wt1+/R394W mice was found to present POF-like phenotype, which indicates that WT1 might be a plausible candidate gene for non-syndromic POF. The coding region of WT1 gene was screened in 384 patients with POF and 6 novel variations were identified, including two missense mutations (p. Pro126Ser in exon1 and p. Arg370His in exon7) and four intronic variants (c.647-27C > T, c.647-13G > C, c.647-13G > A in intron1 and c.950 + 14T > C in intron 4). In vitro experiments showed that both mutant p. Pro126Ser and p. Arg370His repressed the expression of Amh and Cdh1, and induced the expression of Fshr and Cyp19 in mRNA level (P < 0.05). The expression changes of AMH, FSHR, CYP19 and CDH1 were confirmed by western blot. These genes (AMH, FSHR, CYP19 and CDH1) are required for granular cells (GCs) proliferation, differentiation and oocyte-GCs interaction. The novel mutant p. P126S and p. R370H in the WT1 gene potentially impaired GCs differentiation and oocyte-GCs interaction, which might result in loss of follicles prematurely. Therefore, WT1 is a plausible causal gene for POF. PMID:26358501

  4. Mutant WT1 is associated with DNA hypermethylation of PRC2 targets in AML and responds to EZH2 inhibition.

    PubMed

    Sinha, Subarna; Thomas, Daniel; Yu, Linda; Gentles, Andrew J; Jung, Namyoung; Corces-Zimmerman, M Ryan; Chan, Steven M; Reinisch, Andreas; Feinberg, Andrew P; Dill, David L; Majeti, Ravindra

    2015-01-01

    Acute myeloid leukemia (AML) is associated with deregulation of DNA methylation; however, many cases do not bear mutations in known regulators of cytosine guanine dinucleotide (CpG) methylation. We found that mutations in WT1, IDH2, and CEBPA were strongly linked to DNA hypermethylation in AML using a novel integrative analysis of The Cancer Genome Atlas data based on Boolean implications, if-then rules that identify all individual CpG sites that are hypermethylated in the presence of a mutation. Introduction of mutant WT1 (WT1mut) into wild-type AML cells induced DNA hypermethylation, confirming mutant WT1 to be causally associated with DNA hypermethylation. Methylated genes in WT1mut primary patient samples were highly enriched for polycomb repressor complex 2 (PRC2) targets, implicating PRC2 dysregulation in WT1mut leukemogenesis. We found that PRC2 target genes were aberrantly repressed in WT1mut AML, and that expression of mutant WT1 in CD34(+) cord blood cells induced myeloid differentiation block. Treatment of WT1mut AML cells with short hairpin RNA or pharmacologic PRC2/enhancer of zeste homolog 2 (EZH2) inhibitors promoted myeloid differentiation, suggesting EZH2 inhibitors may be active in this AML subtype. Our results highlight a strong association between mutant WT1 and DNA hypermethylation in AML and demonstrate that Boolean implications can be used to decipher mutation-specific methylation patterns that may lead to therapeutic insights. PMID:25398938

  5. Effects of Cerium and Lanthanum on the Corrosion Behavior of Al-3.0 wt.%Mg Alloy

    NASA Astrophysics Data System (ADS)

    Zhang, Xin; Wang, Zehua; Zhou, Zehua; Xu, Jianming

    2016-03-01

    Effects of rare earth elements (RE: cerium and lanthanum) on the corrosion behavior of Al-3.0 wt.%Mg alloy were investigated by electrochemical measurement and immersion test in 3.5 wt.% NaCl solution. The results indicated that a proper amount of rare earth (about 0.2 wt.%) could improve the corrosion resistance of Al-3.0 wt.%Mg alloy effectively, whereas that excessive rare earth addition would increase the corrosion rate and reduce the corrosion resistance. The corrosion behavior of Al-3.0 wt.%Mg alloys in 3.5 wt.% NaCl solution showed typical characteristics of pitting corrosion at the position of second phases. The more and the bigger the second phases, the more and the larger the pitting holes.

  6. A novel repressor, par-4, modulates transcription and growth suppression functions of the Wilms' tumor suppressor WT1.

    PubMed Central

    Johnstone, R W; See, R H; Sells, S F; Wang, J; Muthukkumar, S; Englert, C; Haber, D A; Licht, J D; Sugrue, S P; Roberts, T; Rangnekar, V M; Shi, Y

    1996-01-01

    The tumor suppressor WT1 represses and activates transcription. The loss and/or imbalance of the dual transcriptional activity of WT1 may contribute to Wilms' tumor. In this study, we identified par-4 (for prostate apoptosis response) as a WT1-interacting protein that itself functions as a transcriptional repressor. par-4 contains a putative leucine zipper domain and is specifically upregulated during apoptosis of prostate cells (S. F. Sells, D. P. Wood, Jr., S. S. Joshi-Barve, S. Muthukkumar, R. J. Jacob, S. A. Crist, S. Humphreys, and V. M. Rangnekar, Cell Growth Differ. 5:457-466, 1994). The leucine repeat domain of par-4 was shown to interact with the zinc finger DNA binding domain of WT1. Immunoprecipitation-Western blot (immunoblot) analyses demonstrated in vivo WT1-par-4 interactions. par-4 was ubiquitously expressed, and the protein was found in both the nucleus and the cytoplasm. Functionally, par-4 inhibited transcription activated by WT1, but not by the related protein EGR1. Inhibition of WT1-mediated transcription was dependent on the domain of par-4 that mediates its physical association with WT1. In addition, par-4 augmented WT1-mediated repression, possibly by contributing an additional repression domain. Consistent with these results, par-4 functioned as a transcriptional repressor when brought to a promoter via a heterologous DNA binding domain. Significantly, par-4, but not a mutant unable to interact with WT1, rescued growth suppression caused by WT1. Thus, we identified a novel repressor that modulates transcription as well as growth suppression functions of WT1. PMID:8943350

  7. Microstructure and wear performance of Ni-20 wt.% Pb hypomonotectic alloys

    SciTech Connect

    Xie, H.; Yang, G.C.; La, P.Q.; Hao, W.X.; Fan, J.F.; Liu, W.M.; Xu, L.J

    2004-05-15

    The tribological properties of Ni-20 wt.% Pb alloys were measured by using a ball-on-disc reciprocating tribo-tester. The effects of load, sliding speed and melt undercooling on wear rate of the sample were investigated. The worn surface of Ni-20 wt.% Pb was examined using scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The results show that the wear properties of the samples undercooled by 85 and 390 K are obviously superior, which is attributed to more efficient transfer of Pb from the bulk material to the worn surface. The lubricating film is identified as a mixture of Ni{sub 2}O{sub 3} and lead oxide by XPS analysis. At the same load or sliding speed, the predominant wear mechanisms can be identified as oxidative wear for the lower and larger undercooling and plastic deformation for the medium undercooling.

  8. α-Phase transformation kinetics of U - 8 wt% Mo established by in situ neutron diffraction

    NASA Astrophysics Data System (ADS)

    Steiner, M. A.; Calhoun, C. A.; Klein, R. W.; An, K.; Garlea, E.; Agnew, S. R.

    2016-08-01

    The α-phase transformation kinetics of as-cast U - 8 wt% Mo below the eutectoid temperature have been established by in situ neutron diffraction. α-phase weight fraction data acquired through Rietveld refinement at five different isothermal hold temperatures can be modeled accurately utilizing a simple Johnson-Mehl-Avrami-Kolmogorov impingement-based theory, and the results are validated by a corresponding evolution in the γ-phase lattice parameter during transformation that follows Vegard's law. Neutron diffraction data is used to produce a detailed Time-Temperature-Transformation diagram that improves upon inconsistencies in the current literature, exhibiting a minimum transformation start time of 40 min at temperatures between 500 °C and 510 °C. The transformation kinetics of U - 8 wt% Mo can vary significantly from as-cast conditions after extensive heat treatments, due to homogenization of the typical dendritic microstructure which possesses non-negligible solute segregation.

  9. WT1-specific T cell receptor gene therapy: improving TCR function in transduced T cells.

    PubMed

    Stauss, Hans J; Thomas, Sharyn; Cesco-Gaspere, Michela; Hart, Daniel P; Xue, Shao-An; Holler, Angelika; King, Judy; Wright, Graham; Perro, Mario; Pospori, Constantina; Morris, Emma

    2008-01-01

    Adoptive transfer of antigen-specific T lymphocytes is an attractive form of immunotherapy for haematological malignancies and cancer. The difficulty of isolating antigen-specific T lymphocytes for individual patients limits the more widespread use of adoptive T cell therapy. The demonstration that cloned T cell receptor (TCR) genes can be used to produce T lymphocyte populations of desired specificity offers new opportunities for antigen-specific T cell therapy. The first trial in humans demonstrated that TCR gene-modified T cells persisted for an extended time period and reduced tumor burden in some patients. The WT1 protein is an attractive target for immunotherapy of leukemia and solid cancer since elevated expression has been demonstrated in AML, CML, MDS and in breast, colon and ovarian cancer. In the past, we have isolated high avidity CTL specific for a WT1-derived peptide presented by HLA-A2 and cloned the TCR alpha and beta genes of a WT1-specific CTL line. The genes were inserted into retroviral vectors for transduction of human peripheral blood T lymphocytes of leukemia patients and normal donors. The treatment of leukemia-bearing NOD/SCID mice with T cells transduced with the WT1-specific TCR eliminated leukemia cells in the bone marrow of most mice, while treatment with T cells transduced with a TCR of irrelevant specificity did not diminish the leukemia burden. In order to improve the safety and efficacy of TCR gene therapy, we have developed lentiviral TCR gene transfer. In addition, we employed strategies to enhance TCR expression while avoiding TCR mis-pairing. It may be possible to generate dominant TCR constructs that can suppress the expression of the endogenous TCR on the surface of transduced T cells. The development of new TCR gene constructs holds great promise for the safe and effective delivery of TCR gene therapy for the treatment of malignancies. PMID:17855129

  10. HSV carrying WT REST establishes latency but reactivates only if the synthesis of REST is suppressed.

    PubMed

    Zhou, Guoying; Du, Te; Roizman, Bernard

    2013-02-01

    HSVs transit from vigorous replication at the portal of entry into the body to a latent state in sensory neurons in which only noncoding (e.g., latency-associated transcript) and micro-RNAs are expressed. In productive infection, viral genes must be sequentially derepressed at two checkpoints. A leading role in the repression of viral genes is carried out by histone deacetylase (HDAC)/corepressor element-1 silencing transcription factor (CoREST)/lysinespecific demethylase1(LSD1)/RE1-silencing transcription factor (REST) repressor complex (HCLR). Previously, we reported that to define the role of the components of the HCLR complex in the establishment of latency, we constructed recombinant virus (R112) carrying a dominant-negative REST that bound response elements in DNA but could not recruit repressive proteins. This recombinant virus was unable to establish latency. In the current studies, we constructed a virus (R111) carrying WT REST with a WT genome. We report the following findings: (a) R111 readily established latent infection in trigeminal ganglia; however, although the amounts of viral DNAs in latently infected neurons were similar to those of WT virus, the levels of latency-associated transcript and micro-RNAs were 50- to 100-fold lower; (b) R111 did not spontaneously reactivate in ganglionic organ cultures; however, viral genes were expressed if the synthesis of REST was blocked by cycloheximide; and (c) histone deacetylase inhibitors reactivated the WT parent but not the R111 recombinant virus. The results suggest that REST plays a transient role in the establishment of latency but not in reactivation and suggest the existence of at least two phases at both establishment and reactivation. PMID:23341636

  11. Investigation on hydrogenation performance of Mg{sub 2}Ni+10 wt.% NbN composite

    SciTech Connect

    Zhao, Xin; Han, Shumin; Zhu, Yi; Chen, Xiaocui; Ke, Dandan; Wang, Zhibin; Liu, Ting; Ma, Yufei

    2015-01-15

    The Mg{sub 2}Ni+10 wt.% NbN composite was prepared by mechanical milling and its hydrogen absorption/desorption properties and microstructure were systematically investigated. XRD results indicated that NbN was stable during ball milling process while partly decomposed into NbN{sub 0.95} and NbH during hydriding/dehydriding cycles irreversibly. The composite exhibited excellent hydrogenation/dehydrogenation kinetics performance with 2.71 wt.% hydrogen absorbed in 60 s at 423 K and 0.81 wt.% hydrogen released in 2 h at 523 K, respectively. The H diffusion constant of the composite reached 14.98×10{sup −5} s{sup −1} which was more than twice increased than that of pure Mg{sub 2}Ni powder. The superior hydrogen storage properties of the composite were ascribed to the refined grain size and abundant N-defect points provided by NbN and NbN{sub 0.95} in the composite. - Graphical abstract: The Mg{sub 2}Ni+10 wt.% NbN composite displays improvements on particle size distribution as well as hydrogen storage properties compared with that of pure Mg{sub 2}Ni. - Highlights: • NbN is introduced into Mg{sub 2}Ni hydride by Ar protected ball-milling. • Surfaces of the additive NbN particle are reduced by Mg{sub 2}NiH{sub 4}. • Hydrogenation kinetic property at 423 K is double improved. • Dehydrogenation capacity at 523 K of composites is beyond double improved.

  12. In Vivo Assays for Assessing the Role of the Wilms' Tumor Suppressor 1 (Wt1) in Angiogenesis.

    PubMed

    McGregor, Richard J; Ogley, R; Hadoke, Pwf; Hastie, Nicholas

    2016-01-01

    The Wilms' tumor suppressor gene (WT1) is widely expressed during neovascularization, but it is almost entirely absent in quiescent adult vasculature. However, in vessels undergoing angiogenesis, WT1 is dramatically upregulated. Studies have shown Wt1 has a role in both tumor and ischemic angiogenesis, but the mechanism of Wt1 action in angiogenic tissue remains to be elucidated. Here, we describe two methods for induction of in vivo angiogenesis (subcutaneous sponge implantation, femoral artery ligation) that can be used to assess the influence of Wt1 on new blood vessel formation. Subcutaneously implanted sponges stimulate an inflammatory and fibrotic response including cell infiltration and angiogenesis. Femoral artery ligation creates ischemia in the distal hindlimb and produces an angiogenic response to reperfuse the limb which can be quantified in vivo by laser Doppler flowmetry. In both of these models, the role of Wt1 in the angiogenic process can be assessed using histological/immunohistochemical staining, molecular analysis (qPCR) and flow cytometry. Furthermore, combined with suitable genetic modifications, these models can be used to explore the causal relationship between Wt1 expression and angiogenesis and to trace the lineage of cells expressing Wt1. This approach will help to clarify the importance of Wt1 in regulating neovascularization in the adult, and its potential as a therapeutic target. PMID:27417962

  13. A Project Assessment of Stabilizing System of WT Generation using Rechargeable Battery

    NASA Astrophysics Data System (ADS)

    Kojima, Yasuhiro; Takano, Tomihiro; Tanikawa, Ryoichi; Takagi, Tetsuro; Hirooka, Koutaro; Kumagai, Sadatoshi

    The expansion of the renewable energy introduction is examined as measures for controlling global warming. Wind power generation is expected as effective power resource, but the negative impact from the difficulty of an unstable output is concerned. In recent years, WT generation with contract of cut-of with shorting adjusting power and with rechargeable battery for stabilizing control are examined, but the introduction has not been accelerated yet because there is an influence in WT generation entrepreneur's business. In this paper, we make a brief summary of relation between the fluctuation of wind power generation and stability of electric power operation, and two types of approach; cut-off contract and stabilization using rechargeable battery. For the stabilization using battery, there are two methods, one is reduction control and the other is constant control. We propose a new control method for constant control based on profit optimization considering WT generation forecast and its risk of deviation. We also propose the estimation method for the .limitation of battery installation. Simulation results show the efficiency of our proposed methods.

  14. Process aspects in combustion and gasification Waste-to-Energy (WtE) units.

    PubMed

    Leckner, Bo

    2015-03-01

    The utilisation of energy in waste, Waste to Energy (WtE), has become increasingly important. Waste is a wide concept, and to focus, the feedstock dealt with here is mostly municipal solid waste. It is found that combustion in grate-fired furnaces is by far the most common mode of fuel conversion compared to fluidized beds and rotary furnaces. Combinations of pyrolysis in rotary furnace or gasification in fluidized or fixed bed with high-temperature combustion are applied particularly in Japan in systems whose purpose is to melt ashes and destroy dioxins. Recently, also in Japan more emphasis is put on WtE. In countries with high heat demand, WtE in the form of heat and power can be quite efficient even in simple grate-fired systems, whereas in warm regions only electricity is generated, and for this product the efficiency of boilers (the steam data) is limited by corrosion from the flue gas. However, combination of cleaned gas from gasification with combustion provides a means to enhance the efficiency of electricity production considerably. Finally, the impact of sorting on the properties of the waste to be fed to boilers or gasifiers is discussed. The description intends to be general, but examples are mostly taken from Europe. PMID:24846797

  15. The ability of S.aureus to form biofilm on the Ti-6Al-7Nb scaffolds produced by Selective Laser Melting and subjected to the different types of surface modifications.

    PubMed

    Szymczyk, Patrycja; Junka, Adam; Ziółkowski, Grzegorz; Smutnicka, Danuta; Bartoszewicz, Marzenna; Chlebus, Edward

    2013-01-01

    The Gram-positive coccus, Staphylococcus aureus, is the leading etiologic agent of limb and life-threatening biofilm-related infections in the patients following the orthopaedic implantations. The aim of the present paper is to estimate the ability of S. aureus to form biofilm on titanium alloy (Ti-6Al-7Nb) scaffolds produced by Selective Laser Melting (SLM) and subjected to the different types of surface modifications, including ultrasonic cleaning and chemical polishing. The results obtained indicate significantly the decreased ability of S.aureus to form biofilm on the surface of scaffolds subjected to the chemical polishing in comparison to the scaffolds cleaned ultrasonically. The data provided can be useful for future applications of the SLM technology in production of Ti-6Al-7Nb medical implants. PMID:23957680

  16. Bridge deck surface temperature monitoring by infrared thermography and inner structure identification using PPT and PCT analysis methods

    NASA Astrophysics Data System (ADS)

    Dumoulin, Jean

    2013-04-01

    One of the objectives of ISTIMES project was to evaluate the potentialities offered by the integration of different electromagnetic techniques able to perform non-invasive diagnostics for surveillance and monitoring of transport infrastructures. Among the EM methods investigated, we focused our research and development efforts on uncooled infrared camera techniques due to their promising potential level of dissemination linked to their relative low cost on the market. On the other hand, works were also carried out to identify well adapted implementation protocols and key limits of Pulse Phase Thermography (PPT) and Principal Component Thermography (PCT) processing methods to analyse thermal image sequence and retrieve information about the inner structure. So the first part of this research works addresses infrared thermography measurement when it is used in quantitative mode (not in laboratory conditions) and not in qualitative mode (vision applied to survey). In such context, it requires to process in real time thermal radiative corrections on raw data acquired to take into account influences of natural environment evolution with time, thanks to additional measurements. But, camera sensor has to be enough smart to apply in real time calibration law and radiometric corrections in a varying atmosphere. So, a complete measurement system was studied and developed [1] with low cost infrared cameras available on the market. In the system developed, infrared camera is coupled with other sensors to feed simplified radiative models running, in real time, on GPU available on small PC. The whole measurement system was implemented on the "Musmeci" bridge located in Potenza (Italy). No traffic interruption was required during the mounting of our measurement system. The infrared camera was fixed on top of a mast at 6 m elevation from the surface of the bridge deck. A small weather station was added on the same mast at 1 m under the camera. A GPS antenna was also fixed at the

  17. Deformation of as-cast LiF-22 mol pct CaF2 hypereutectic salt between 500 and 1015 K

    NASA Technical Reports Server (NTRS)

    Raj, S. V.; Whittenberger, J. D.

    1990-01-01

    Results are presented on compression tests conducted on as-cast LiF-22 mol pct CaF2 hypereutectic specimens at nominal strain rates between 1.8 x 10 to the -6th/sec and 0.25/sec over the temperature range 500-1015 K. In all instances, the stress-strain curves showed broad maxima, with negative strain-hardening rates after the peak stress sigma(max). It was found that, at low temperatures and high stresses, the CaF2 lamellae are rigid while the LiF matrix exhibits extensive transgranular cavitation, while at high temperatures and low stresses the CaF2 lamellae break down and spheroidize while the LiF matrix does not cavitate. It was concluded that the mechanical properties of the as-cast hypereutectic LiF-22 mol pct CaF2 are governed by the rate of deformation of the CaF2 phase. It is suggested that, for thermal energy storage applications, a spheroidal microstructure is more desirable than a lamellar structure.

  18. In Situ Observations of the Deformation Behavior and Fracture Mechanisms of Ti-45Al-2Nb-2Mn + 0.8 vol pct TiB2

    NASA Astrophysics Data System (ADS)

    Muñoz-Moreno, Rocio; Boehlert, Carl J.; Pérez-Prado, M. Teresa; Ruiz-Navas, Elisa M.; Llorca, Javier

    2012-04-01

    The deformation and fracture mechanisms of a nearly lamellar Ti-45Al-2Nb-2Mn (at. pct) + 0.8 vol pct TiB2 intermetallic, processed into an actual low-pressure turbine blade, were examined by means of in situ tensile and tensile-creep experiments performed inside a scanning electron microscope (SEM). Low elongation-to-failure and brittle fracture were observed at room temperature, while the larger elongations-to-failure at high temperature facilitated the observation of the onset and propagation of damage. It was found that the dominant damage mechanisms at high temperature depended on the applied stress level. Interlamellar cracking was observed only above 390 MPa, which suggests that there is a threshold below which this mechanism is inhibited. Failure during creep tests at 250 MPa was controlled by intercolony cracking. The in situ observations demonstrated that the colony boundaries are damage nucleation and propagation sites during tensile creep, and they seem to be the weakest link in the microstructure for the tertiary creep stage. Therefore, it is proposed that interlamellar areas are critical zones for fracture at higher stresses, whereas lower stress, high-temperature creep conditions lead to intercolony cracking and fracture.

  19. Crossed-Wire Laser Microwelding of Pt-10 Pct Ir to 316 LVM Stainless Steel: Part II. Effect of Orientation on Joining Mechanism

    NASA Astrophysics Data System (ADS)

    Huang, Y. D.; Pequegnat, A.; Zou, G. S.; Feng, J. C.; Khan, M. I.; Zhou, Y.

    2012-04-01

    With the increasing complexity of medical devices and with efforts to reduce manufacturing costs, challenges arise in joining dissimilar materials. In this study, the laser weldability of dissimilar joints between Pt-10 pct Ir and 316 low-carbon vacuum melted (LVM) stainless steel (SS) crossed wires was investigated by characterizing the weld geometry, joint strength, morphology of weld cross sections, and differences in joining behavior, depending on which material is subject to the incident laser beam. With the Pt-Ir alloy on top, a significant amount of porosity was observed on the surface of the welds as well as throughout the weld cross sections. This unique form of porosity is believed to be a result of preferential vaporization of 316 LVM SS alloying elements that become mixed with the molten Pt-10 pct Ir during welding. The joining mechanism documented in micrographs of cross-sectioned welds was found to transition from laser brazing to fusion welding. It is inferred that the orientation of the two dissimilar metals ( i.e., which material is subject to the incident laser beam) plays an important role in weld quality of crossed-wire laser welds.

  20. CTNNB1 mutations and overexpression of Wnt/beta-catenin target genes in WT1-mutant Wilms' tumors.

    PubMed

    Li, Chi-Ming; Kim, Connie E; Margolin, Adam A; Guo, Meirong; Zhu, Jimmy; Mason, Jacqueline M; Hensle, Terrence W; Murty, Vundavalli V V S; Grundy, Paul E; Fearon, Eric R; D'Agati, Vivette; Licht, Jonathan D; Tycko, Benjamin

    2004-12-01

    Gain-of-function mutations in exon 3 of beta-catenin (CTNNB1) are specific for Wilms' tumors that have lost WT1, but 50% of WT1-mutant cases lack such "hot spot" mutations. To ask whether stabilization of beta-catenin might be essential after WT1 loss, and to identify downstream target genes, we compared expression profiles in WT1-mutant versus WT1 wild-type Wilms' tumors. Supervised and nonsupervised hierarchical clustering of the expression data separated these two classes of Wilms' tumor. The WT1-mutant tumors overexpressed genes encoding myogenic and other transcription factors (MOX2, LBX1, SIM2), signaling molecules (TGFB2, FST, BMP2A), extracellular Wnt inhibitors (WIF1, SFRP4), and known beta-catenin/TCF targets (FST, CSPG2, CMYC). Beta-Catenin/TCF target genes were overexpressed in the WT1-mutant tumors even in the absence of CTNNB1 exon 3 mutations, and complete sequencing revealed gain-of-function mutations elsewhere in the CTNNB1 gene in some of these tumors, increasing the overall mutation frequency to 75%. Lastly, we identified and validated a novel direct beta-catenin target gene, GAD1, among the WT1-mutant signature genes. These data highlight two molecular classes of Wilms' tumor, and indicate strong selection for stabilization of beta-catenin in the WT1-mutant class. Beta-Catenin stabilization can initiate tumorigenesis in other systems, and this mechanism is likely critical in tumor formation after loss of WT1. PMID:15579438

  1. Fraction eutectic measurements in slowly cooled Pb - 15 wt percent Sn alloys

    NASA Technical Reports Server (NTRS)

    Studer, Anthony C.; Laxmanan, V.

    1988-01-01

    A space shuttle experiment employing the General Purpose Furnace in its isothermal mode of operation is currently manifested for flight circa 1989. The aim of this experiment was to investigate the role of gravity in a slowly, and isothermally, cooled sample of a binary Pb - 15 wt percent Sn alloy. Ground based work in support of the microgravity experiment is discussed. In particular, it is shown that fraction eutectic measurements using an image analyzer, can be used to satisfactorily describe macrosegregation occurring in these slowly cooled ingots.

  2. Microstructure and crystallographic texture of strip-cast 4.3wt%Si steel sheet

    SciTech Connect

    Park, J.Y.; Oh, K.H.; Ra, H.Y.

    1999-03-19

    Since grain oriented silicon steel sheet was invented in 1935 by Goss, the material has been of considerable fundamental and technological interest to improve the sharpness of Goss orientation {l_brace}110{r_brace}{l_angle}100{r_angle} etc. In the present study, a Fe-4.3wt%Si strip was produced by the vertical type twin roll strip casting process and the microstructure and texture through the thickness direction were studied by optical metallography and quantitative X-ray texture analysis. The inhomogeneity of the texture and microstructure through the thickness direction were investigated.

  3. Molecular Dynamics Simulation of γS-WT and γS-G18V

    NASA Astrophysics Data System (ADS)

    Ozawa, Ai; Yamada, Hironao; Mori, Sakiko; Noguchi, Yoh; Miyakawa, Takeshi; Morikawa, Ryota; Takasu, Masako

    γS-crystallin maintains transparency of the crystalline lens and increases the refraction index of lens. γS-G18V is a mutant γS-crystallin in which 18th glycine is replaced by valine. This protein is related to childhood-onset cortical cataract. In this paper, we study the fluctuation of residues and dihedral angles, and investigate the difference between γS-WT and γS-G18V by using molecular dynamics simulation. In the result of RMSF, we found large difference around the mutation point. In addition, differences of dihedral angles of cysteins were found in this area.

  4. Environmental impact assessment of a WtE plant after structural upgrade measures.

    PubMed

    Passarini, Fabrizio; Nicoletti, Monica; Ciacci, Luca; Vassura, Ivano; Morselli, Luciano

    2014-04-01

    The study focuses on analysing the evolution of environmental impacts caused by a medium-large Italian WtE plant before and after revamping and maintenance operations, with the aim of providing an evaluation of how much these structural upgrade measures may affect the total environmental performance. LCA methodology was applied for the modelling and comparison of six WtE scenarios, each describing the main structural upgrades carried out in the plant over the years 1996-2011. The comparison was conducted by adopting 1ton of MSW as the functional unit, and the net contribution from energy recovery to power generation was distinguished by defining consistent national grid electricity mixes for every year considered. The Ecoindicator99 2.09 impact assessment method was used to evaluate the contribution to midpoint and endpoint categories (e.g. carcinogens, respiratory inorganics and organics, climate change, damage to human health). Lastly, the "Pedigree quality matrix" was applied to verify the reliability and robustness of the model created. As expected, the results showed better environmental scores after both the implementation of new procedures and the integration of operations. However, while a net reduction of air emissions seems to be achievable through dedicated flue gas treatment technologies, outcomes underscored potentials for improving the management of bottom ash through the adoption of alternative options aimed to use that solid residue mainly as filler, and to decrease risks from its current disposal in landfill. If the same effort that is put into flue gas treatment were devoted to energy recovery, the targets for the WtE plant could be easily met, achieving a higher sustainability. This aspect is even more complex: national policies for implementing greener and renewable energy sources would result in a lower impact of the national energy mix and, hence, in a lower net avoided burden from energy recovery. The study confirmed the expected improvements

  5. Ending in wonder: replacing technology with revelation in Margaret Edson's W;t.

    PubMed

    Jones, Therese

    2007-01-01

    Margaret Edson's play W;t (1999) serves both as a guide to apprehending the dangers of a perspective that privileges the technological over the aesthetic and as a model for appreciating the magic of yielding to a performance. Inspired by William F. Pinar's (1995) examination of the place and value of the aesthetic in contemporary American education, this article considers Edson's play in relation to theory, teaching, learning, and art, in order to resituate the humanities--with their emphasis on imagination, transformation, and wonder--within the medical arena. PMID:17660633

  6. Elastic Properties of Rolled Uranium -- 10 wt.% Molybdenum Nuclear Fuel Foils

    SciTech Connect

    D. W. Brown; D. J. Alexander; K. D. Clarke; B. Clausen; M. A. Okuniewski; T. A. Sisneros

    2013-11-01

    In situ neutron diffraction data was collected during elastic loading of rolled foils of uranium-10 wt.% molybdenum bonded to a thin layer of zirconium. Lattice parameters were ascertained from the diffraction patterns to determine the elastic strain and, subsequently, the elastic moduli and Poisson’s ratio in the rolling and transverse directions. The foil was found to be elastically isotropic in the rolling plane with an effective modulus of 86 + / - 3 GPa and a Poisson’s ratio 0.39 + / - 0.04.

  7. Engineering WT1-Encoding mRNA to Increase Translational Efficiency in Dendritic Cells.

    PubMed

    Benteyn, Daphné; Heirman, Carlo; Thielemans, Kris; Bonehill, Aude

    2016-01-01

    Dendritic cells (DCs) are the orchestrators of the immune system and are frequently used in clinical trials in order to boost the immune system in cancer patients. Among several available techniques for DC modification, mRNA electroporation is an interesting technique due to the favorable characteristics of mRNA. Antigen expression level and duration can be increased by multiple optimizations of an antigen-encoding mRNA template. Here, we describe different molecular modifications to a WT1-encoding mRNA construct in order to increase antigen expression and the subsequent introduction of mRNA into DCs. PMID:27236795

  8. Effect of 4 wt.% Cr on microstructure, corrosion resistance and tribological properties of Fe{sub 3}Al–20 wt.%Al{sub 2}O{sub 3} composites

    SciTech Connect

    Bai, Yaping Xing, Jiandong Ma, Shengqiang Huang, Qian He, Yuanyuan Liu, Zhen Gao, Yimin

    2013-04-15

    Fe{sub 3}Al–20 wt.%Al{sub 2}O{sub 3} ultrafine grained composites with 4 wt.% Cr were prepared by mechanical alloying inducing self propagating high temperature synthesis with subsequent plasma activated sintering. Microstructures of the composites were studied by X-ray diffraction, scanning electron microscopy, energy dispersive spectrum and transmission electron microscope. Then the relative density, room temperature hardness, static corrosion resistance and dry sliding wear behavior at a temperature range of 25 °C–800 °C of the sintered samples were tested and analyzed. The results showed that the composites had high hardness and a good microstructure with fine grain size, high relative density. The composites with 4 wt.% Cr amount also exhibited excellent comprehensive tribological properties at medium–high temperatures especially at a temperature above 500 °C, although the wear resistance did not be improved at 25 °C–500 °C. 4 wt.% Cr element addition improved the corrosion resistance of the composites significantly with the corrosion loss decreasing by 19.48%. - Highlights: ► In-situ Fe{sub 3}Al–20 wt.%Al{sub 2}O{sub 3} composites with 4 wt.% Cr was prepared by MA-PAS. ► Composites had good tribological properties at the temperature above 500 °C. ► Corrosion resistance was improved obviously by 4 wt.% Cr amount.

  9. Structure and phase stability of a Pu-0.32 wt% Ga alloy

    NASA Astrophysics Data System (ADS)

    Wheeler, D. W.; Ennaceur, S. M.; Matthews, M. B.; Roussel, P.; Bayer, P. D.

    2016-08-01

    In plutonium-gallium (Pu-Ga) alloys that have a Ga content of 0.3-0.4 wt%, their readiness to transform to α‧ renders them of particular interest in efforts to understand the tenuous nature of δ phase stability. The present study is a comprehensive examination of the structure and phase stability of a cast Pu-0.32 wt% Ga alloy, the Ga content being close to the minimum amount needed to retain the δ phase to ambient temperature. The alloy was characterised in both the as-cast condition as well as following a homogenising heat treatment. The 250-h heat treatment at 450 °C was shown to achieve an apparently stable δ-Pu phase. However, the stability of the δ-Pu phase was shown to be marginal: partial transformation to α‧-Pu was observed when the alloy was subjected to hydrostatic compression. Similar transformation was also apparent during metallographic preparation as well as during hardness indentation. The results provide new understanding of the nature of δ phase stability.

  10. Analytical and experimental studies on the strain rate effects in penetration of 10wt % ballistic gelatin

    NASA Astrophysics Data System (ADS)

    Liu, L.; Jia, Z.; Ma, X. L.; Fan, Y. R.

    2013-07-01

    This work concentrates on modeling the super-elastic behavior of 10wt% ballistic gelatin at 4°C and the mechanical responses at quasi-static and high-speed penetrations. Uniaxial compression and simple shearing experiments were carried out to determine the moduli in Mooney-Rivlin model describing the elastic behavior of gelatin at low strain rates. The failure mode is determined to be elastic fracture as the tensile stretch ratio exceeds a critical value. For high compression strain rates, the available results from the split Hopkinson pressure bar (SHPB) experiments for 10wt% gelatin were carefully examined and assessed. Linear relationship between the moduli and the strain rate is established. Based on these material parameters, an analytic solution of stress for the quasi-static and quasi-dynamic expansion of spherical cavity in gelatin is derived. As a consequence, the work needed to open unit volume of cavity, Ps, which is the key parameter in studying penetration problems, is linearly increasing with the characteristic strain rate. The application of Ps to our quasi-static and high-speed penetration experiments is discussed and assessed.

  11. Therapeutic bispecific T-cell engager antibody targeting the intracellular oncoprotein WT1

    PubMed Central

    Dao, Tao; Pankov, Dmitry; Scott, Andrew; Korontsvit, Tatyana; Zakhaleva, Victoriya; Xu, Yiyang; Xiang, Jingyi; Yan, Su; de Morais Guerreiro, Manuel Direito; Veomett, Nicholas; Dubrovsky, Leonid; Curcio, Michael; Doubrovina, Ekaterina; Ponomarev, Vladimir; Liu, Cheng; O’Reilly, Richard J; Scheinberg, David A

    2015-01-01

    Intracellular tumor antigens presented on the cell surface in the context of human leukocyte antigen (HLA) molecules have been targeted by T cell–based therapies, but there has been little progress in developing small-molecule drugs or antibodies directed to these antigens. Here we describe a bispecific T-cell engager (BiTE) antibody derived from a T-cell receptor (TCR)-mimic monoclonal antibody (mAb) ESK1, which binds a peptide derived from the intracellular oncoprotein WT1 presented on HLA-A*02:01. Despite the very low density of the complexes at the cell surface, ESK1-BiTE selectively activated and induced proliferation of cytolytic human T cells that killed cells from multiple leukemias and solid tumors in vitro and in mice. We also discovered that in an autologous in vitro setting, ESK1-BiTE induced a robust secondary CD8 T-cell response specific for tumor-associated antigens other than WT1. Our study provides an approach that targets tumor-specific intracellular antigens without using cell therapy and suggests that epitope spreading could contribute to the therapeutic efficacy of this BiTE. PMID:26389576

  12. Characterization of Hypereutectic Al-20wt%Si/TiCp Metal Matrix Composite

    NASA Astrophysics Data System (ADS)

    Choi, Jinmyung; Park, Seulki; Park, Bonggyu; Park, Ikmin; Park, Yongho; Kim, Yongjin

    Hypereutectic Al-Si alloys are one of the most interesting material for high strength structural components because they have low coefficient of thermal expansion (CTE) as well as high wear resistance and mechanical properties. However, Al-based alloys have lower hardness and wear resistance than ferrous alloys and these disadvantages restrict the use of al-based alloy. They could be overcome by making composite reinforced with ceramic particles. TiC was good candidate for the reinforcement of the alloy. Al-20wt%Si was fabricated by gas atomization and 1, 3 and 5wt%TiC were mixed to these powders by turbular mixer for 10h with 45rpm. The mixture was hot-pressed at 550℃C for 1h under 60MPa pressure. Relative density of the sintered samples was about 98% of theoretical density. The effect of reinforcements on mechanical properties and wear resistance of composite was investgated. Strength, hardness and wear resistance of the sintered sample were improved by the grain refinement and dispersion strengthening.

  13. Design assessment of a 150 kWt CFBC Test Unit

    SciTech Connect

    Batu, A.; Selcuk, N.; Kulah, G.

    2010-04-15

    For clean and efficient energy generation from coal, the most suitable technology known to date is 'Fluidized Bed Combustion' technology. Applications of circulating fluidized bed (CFB) combustion technology have been steadily increasing in both capacity and number over the past decade. Designs of these units have been based on the combustion tests carried out in pilot scale facilities to determine the combustion and desulfurization characteristics of coal and limestone reserves in CFB conditions. Similarly, utilization of Turkish lignites in CFB boilers necessitates adaptation of CFB combustion technology to these resources. However, the design of these test units are not based on firing coals with high ash, volatile matter and sulfur contents like Turkish lignites. For this purpose, a 150 kWt CFB combustor test unit is designed and constructed in Chemical Engineering Department of Middle East Technical University, based on the extensive experience acquired at the existing 0.3 MWt Bubbling Atmospheric Fluidized Bed Combustor (AFBC) Test Rig. Following the commissioning tests, a combustion test is carried out for investigation of combustion characteristics of Can lignite in CFB conditions and for assessment of the design of test unit. Comparison of the design outputs with experimental results reveals that most of the predictions and assumptions have acceptable agreement with the operating conditions. In conclusion, the performance of 150 kWt CFBC Test Unit is found to be satisfactory to be utilized for the long term research studies on combustion and desulfurization characteristics of indigenous lignite reserves in circulating fluidized bed combustors. (author)

  14. G1 phase arrest induced by Wilms tumor protein WT1 is abrogated by cyclin/CDK complexes.

    PubMed Central

    Kudoh, T; Ishidate, T; Moriyama, M; Toyoshima, K; Akiyama, T

    1995-01-01

    WT1, the Wilms tumor-suppressor gene, maps to the human chromosomal region 11p13 and encodes a transcriptional repressor, WT1, implicated in controlling normal urogenital development. Microinjection of the WT1 cDNA into quiescent cells or cells in early to mid G1 phase blocked serum-induced cell cycle progression into S phase. The activity of WT1 varied significantly depending on the presence or absence of an alternatively spliced region located upstream of the zinc finger domain. The inhibitory activity of WT1 was abrogated by the overexpression of cyclin E/CDK2 as well as cyclin D1/CDK4. Furthermore, both CDK4- and CDK2-associated kinase activities were downregulated in cells overexpressing WT1, whereas the levels of CDK4, CDK2, and cyclin D1 expression were unchanged. These findings suggest that inhibition of the activity of cyclin/CDK complexes may be involved in mediating the WT1-induced cell cycle block. Images Fig. 1 Fig. 2 PMID:7753836

  15. Clinical usefulness of WT1 mRNA expression in bone marrow detected by a new WT1 mRNA assay kit for monitoring acute myeloid leukemia: a comparison with expression of WT1 mRNA in peripheral blood.

    PubMed

    Kitamura, Kunio; Nishiyama, Takahiro; Ishiyama, Ken; Miyawaki, Shuichi; Miyazaki, Kanji; Suzuki, Kenshi; Masaie, Hiroaki; Okada, Masaya; Ogawa, Hiroyasu; Imai, Kiyotoshi; Kiyoi, Hitoshi; Naoe, Tomoki; Yokoyama, Yasuhisa; Chiba, Shigeru; Hata, Tomoko; Miyazaki, Yasushi; Hatta, Yoshihiro; Takeuchi, Jin; Nannya, Yasuhito; Kurokawa, Mineo; Ueda, Yasunori; Koga, Daisuke; Sugiyama, Haruo; Takaku, Fumimaro

    2016-01-01

    We have previously shown the clinical usefulness of Wilms' tumor 1 gene (WT1) mRNA expression in peripheral blood (PB) as a minimal residual disease (MRD) monitoring marker in 191 acute myeloid leukemia (AML) patients using the WT1 mRNA assay kit "Otsuka" (Otsuka Pharmaceutical Co., Ltd.; "former kit"). In contrast, the usefulness of WT1 mRNA expression in bone marrow (BM) has been investigated in only a limited number of subjects using former kit. Following that previous study, a next-generation kit, WT1 mRNA assay kit II "Otsuka" (Otsuka Pharmaceutical Co., Ltd.; "new kit") has been newly developed. In the present study, we aimed to evaluate the performance of the new kit and to investigate the clinical usefulness of WT1 mRNA expression in BM. The PB and BM were collected on the same day from 164 blood disease patients, including 118 AML patients. WT1 mRNA expression was determined using the new and former kits and the values obtained were compared. The performance of new kit was shown to be equivalent to that of former kit. As reported in PB, WT1 mRNA expression in BM was found to be a useful marker for monitoring disease status as well as for a diagnosis of early stage relapse in AML patients. PMID:26520650

  16. A simple application of the Bailey-Orowan creep model to Fe-39.8 at. pct Al and gamma/gamma prime - alpha

    NASA Technical Reports Server (NTRS)

    Whittenberger, J. D.; Krishnan, R. V.

    1984-01-01

    The results of a study to determine the recovery rates and work-hardening coefficients for creep from constant cross-head speed compressive tests are presented. Stressing and straining rates are computed from measured time-load curves obtained from compression testing between 1200 and 1400 K of several B2 crystal structure Fe-39.8 Al intermetallic materials and the directionally solidified eutectic alloy gamma/gamma prime alpha. These quantities are then fitted to the universal form of the Bailey-Orowan equation for creep. The recovery rates were found to be functions of nominal strain rate, stress, and temperature, while the hardening coefficients were dependent only on temperature. While the work-hardening coefficient for gamma/gamma prime - alpha was about 0.05 of the elastic modulus, the work-hardening coefficients for Fe-39.8 at. pct Al were less than 0.002 of the modulus.

  17. Effects of casting conditions and deformation processing on A356 aluminum and A356-20 vol. pct SiC composites

    NASA Technical Reports Server (NTRS)

    Rozak, G. A.; Lewandowski, J. J.; Wallace, J. F.; Altmisoglu, A.

    1992-01-01

    The effects of casting conditions and deformation processing on the mechanical properties of unreinforced A356 aluminum and A356-20 vol pct SiC composite were investigated by tensile properties in these compounds fabricated by either sand casting or squeeze casting techniques followed by hot working to 33, 50, 90, and 95 percent reductions. The evolution of the microstructure and values of tensile properties were evaluated for the cast materials in each of the hot worked conditions. It was found that, while the deformation processing of the sand-cast composite resulted in banding of the Al and SiC particles within the microstructure, such features were not observed in the squeeze-cast microstructure. The tensile strengths of the squeeze cast materials was found to be higher than those of the sand cast materials, for both the unreinforced and composite samples, while increased amounts of deformation were found to improve the ductility of the composite.

  18. Temperature dependence of the elastic moduli and damping for polycrystalline LiF-22 pct CaF2 eutectic salt

    NASA Technical Reports Server (NTRS)

    Wolfenden, A.; Lastrapes, G.; Duggan, M. B.; Raj, S. V.

    1991-01-01

    Young's and shear moduli and damping were measured for as-cast polycrystalline LiF-(22 mol pct)CaF2 eutectic specimens as a function of temperature using the piezoelectric ultrasonic composite oscillator technique. The shear modulus decreased with increasing temperature from about 40 GPa at 295 K to about 30 GPa at 1000 K, while the Young modulus decreased from about 115 GPa at 295 K to about 35 GPa at 900 K. These values are compared with those derived from the rule of mixtures using elastic moduli data for LiF and CaF2 single crystals. It is shown that, while the shear modulus data agree reasonably well with the predicted trend, there is a large discrepancy between the theoretical calculations and the Young modulus values, where this disagreement increases with increasing temperature.

  19. The Influences of Interfacial Characteristics and Subsurface Microstructural Evolution on Wear Behavior of Al/A206-5 Pct Alumina Micro/Nano-Composites

    NASA Astrophysics Data System (ADS)

    Tahamtan, Saleh; Halvaee, Ayyoub; Emamy, Masoud

    2015-03-01

    Al206-5 pct aluminap cast composites were fabricated by the injection of (i) the as-received alumina particles and (ii) milled mixture of alumina with Al and Mg powders [composite powder (CP)] into semi-solid Al alloy. The influences of interfacial characteristics as well as microstructural evolution on wear properties were then explored. Microstructures of the composite, worn surfaces, and worn surface side views were characterized by field emission scanning electron microscopy and transmission electron microscopy, and interfacial failure loads were evaluated by high load nano-indentation test. Obtained results revealed augmented wear resistance in the composites fabricated via CP injection into the semi-solid alloy. Improvement in wear resistance was ascribed to lower thickness and higher bonding strength of alumina/matrix interface as well as uniform distribution of grains as a consequence of recrystallization beneath the worn surface.

  20. Evaluation of Solid-Solution Hardening of Fe-27 at. pct Al by Vanadium and Comparison to Precipitation Strengthening by Vanadium Carbides

    NASA Astrophysics Data System (ADS)

    Kratochvíl, Petr; Pešička, Josef; Král, Robert; Švec, Martin; Palm, Martin

    2015-11-01

    The compressive yield stress of Fe-27Al- xV(-C) ( x = 0 to 4 at. pct) at 1073 K (800 °C) has been determined. The increase of the yield stress of Fe-Al by increasing vanadium content is explained by solid-solution hardening. The experimentally observed values of the yield stress at 1073 K (800 °C) are compared with the strengthening given by theories evaluating the interaction between solute atoms and dislocations. The experimental results fit well the increase of the yield stress by the interaction of the solute atoms with screw dislocations. Further increase in yield strength in similar alloys due to vanadium carbides is documented. Precipitated carbides were identified by transmission electron microscopy and Kikuchi patterns. Although precipitation of vanadium carbides increases the compressive yield stress, they also could result in premature failure in tension as their highly anisotropic shape may facilitate crack nucleation.

  1. Activities of FetO in CaO-Al2O3-SiO2-FetO (<5 pct) slags saturated with liquid iron

    NASA Astrophysics Data System (ADS)

    Lee, Kwang Ro; Suito, Hideaki

    1994-12-01

    The activity coefficients of FetO in CaO-Al2O3 and CaO-Al2O3-SiO2 slags with 0.01 to 5 mass pct FetO were determined at 1873 K from the data obtained in the present and previous slag-metal experiments, using an alumina or lime crucible. It was found that the activity coefficients of FetO obeyed a dilute solution law and increased with increasing the content of SiO2. Based on the findings pertaining to the activity coefficient, the values for the activities of SiO2 and Al2O3 in CaO-Al2O3-SiO2 slags were assessed.

  2. Solidification analysis of a centrifugal atomizer using the Al-32.7wt.% Cu alloy

    SciTech Connect

    Osborne, M.G.

    1998-02-23

    A centrifugal atomizer (spinning disk variety) was designed and constructed for the production of spherical metal powders, 100--1,000 microns in diameter in an inert atmosphere. Initial atomization experiments revealed the need for a better understanding of how the liquid metal was atomized and how the liquid droplets solidified. To investigate particle atomization, Ag was atomized in air and the process recorded on high-speed film. To investigate particle solidification, Al-32.7 wt.% Cu was atomized under inert atmosphere and the subsequent particles were examined microscopically to determine solidification structure and rate. This dissertation details the experimental procedures used in producing the Al-Cu eutectic alloy particles, examination of the particle microstructures, and determination of the solidification characteristics (e.g., solidification rate) of various phases. Finally, correlations are proposed between the operation of the centrifugal atomizer and the observed solidification spacings.

  3. Effect of preliminary deformation on heat of melting of superplastic eutectic alloy Bi-43 wt % Sn

    NASA Astrophysics Data System (ADS)

    Korshak, V. F.; Tkachenko, M. V.

    2013-11-01

    Studies have been performed on the effect of external compressive stress applied to samples of superplastic eutectic Bi-43 wt % Sn alloy during heating to a near-eutectic temperature on the specific heat of melting of the alloy. The alloy was prepared from chemically pure components by casting onto a massive copper substrate. After compression by ˜65% using a hydraulic press, the ingots were aged in air for approximately 7 months. The experiments were carried out using the method of differential thermal analysis. The samples were loaded using a specially designed device. A regular decrease in the specific heat of melting by ˜37% has been revealed while increasing the external pressure from 0 to 4.4 MPa. The experimental results are discussed using the available literature data on the heat of melting of the alloy and on the structure of the eutectic.

  4. Microstructural Evolution and Mechanical Properties of Au-20wt.%Sn|Ni Interconnection

    NASA Astrophysics Data System (ADS)

    Dong, H. Q.; Vuorinen, V.; Liu, X. W.; Laurila, T.; Li, J.; Paulasto-Kröckel, M.

    2016-01-01

    In this paper, the microstructural evolution and properties of Au-20wt.%Sn|Ni reaction couples were investigated from two perspectives: (1) by analyzing the microstructure of the as-soldered and aged samples, as well as (2) by measuring the mechanical properties of the intermetallic compounds formed within the reaction zone. The evolution of interfacial reaction products for both the as-soldered and aged interconnections was rationalized by using the experimental results in combination with assessed thermodynamic data from the Au-Ni-Sn system. Moreover, nanoindentation tests were implemented to measure the indentation modulus and hardness of the compounds formed at the interface. It was found that aging had a negligible influence on the elastic modulus and hardness of AuSn and Au5Sn, while the solubility of the third element significantly changed the indentation modulus and hardness of the intermetallic compounds.

  5. Analysis of irradiated U-7wt%Mo dispersion fuel microstructures using automated image processing

    DOE PAGESBeta

    Collette, R.; King, J.; Buesch, C.; Keiser, Jr., D. D.; Williams, W.; Miller, B. D.; Schulthess, J.

    2016-04-01

    The High Performance Research Reactor Fuel Development (HPPRFD) program is responsible for developing low enriched uranium (LEU) fuel substitutes for high performance reactors fueled with highly enriched uranium (HEU) that have not yet been converted to LEU. The uranium-molybdenum (U-Mo) fuel system was selected for this effort. In this study, fission gas pore segmentation was performed on U-7wt%Mo dispersion fuel samples at three separate fission densities using an automated image processing interface developed in MATLAB. Pore size distributions were attained that showed both expected and unexpected fission gas behavior. In general, it proved challenging to identify any dominant trends whenmore » comparing fission bubble data across samples from different fuel plates due to varying compositions and fabrication techniques. Here, the results exhibited fair agreement with the fission density vs. porosity correlation developed by the Russian reactor conversion program.« less

  6. Dendrite growth morphologies in rapidly solidified Al-4.5wt.%Cu droplets

    NASA Astrophysics Data System (ADS)

    Bedel, M.; Reinhart, G.; Bogno, A.-A.; Nguyen-Thi, H.; Boller, E.; Gandin, Ch-A.; Henein, H.

    2016-03-01

    The impulse atomization process developed at the University of Alberta (Canada) enables metallic powders to be solidified with controlled process parameters and improved properties. In order to investigate the microstructure morphologies in droplets of Al- 4.5wt.%Cu alloys, three-dimensional reconstructions of several droplets are obtained by using synchrotron X-ray micro-tomography, allowing a visualization of the inner microstructure in three dimensions. The analysis of the reconstructed volumes reveals that a wide range of morphology, from highly branched to “finger-bundle”, can be obtained for different droplets of similar diameter and produced in the same batch. Unexpectedly for this alloy, microstructural features also indicate that the development of the dendrite arms (primary and of higher orders) occurs in most droplets along <111> crystallographic axes, instead of the usual <100> directions observed in conventional casting technologies.

  7. Effect of temperature on excited-state proton tunneling in wt-green fluorescent protein.

    PubMed

    Leiderman, P; Gepshtein, R; Tsimberov, I; Huppert, Dan

    2008-01-31

    Steady-state emission and time-correlated single-photon counting (TCSPC) are used to measure the temperature dependence of the proton-transfer rate of wt-GFP in H2O and D2O. As the temperature decreases, the proton-transfer rate from the protonated form slows down. At about 80 K, the rate is about 10-fold slower than the rate at room temperature. At lower temperatures of 70 K down to 13 K (the lowest temperature studied), the rate of proton transfer is almost temperature independent. We explain the temperature dependence of the proton-transfer rate by an intermolecular vibration assisted tunneling mechanism. We attribute the specific intermolecular vibration to the oscillation of two oxygen atoms: the chromophore's phenol ring and the nearby water molecule. The kinetic isotope effect is about 5 and is almost temperature independent. PMID:18181609

  8. The Corrosion Behavior of Ni3(Si,Nb) Alloys in Boiling 70 wt.% Sulfuric Acid

    NASA Astrophysics Data System (ADS)

    Hsu, Jen-Hsien; Larson, Christopher M.; Newkirk, Joseph W.; Brow, Richard K.; Zhang, San-Hong

    2016-02-01

    Corrosion-resistant Ni3(Si,Nb) alloys are promising materials of construction for hydrogen-production systems based on the sulfur-iodine thermochemical cycle. In this work, the corrosion rates of three different Ni3(Si,Nb) alloys were measured in boiling 70 wt.% sulfuric acid and a three-stage corrosion mechanism was identified, based on the composition and morphology of surface scale that developed. The α(Ni) + β(Ni3Si) eutectic constituent of the alloy microstructure was selectively attacked by acid and, when present, is detrimental to corrosion resistance. The G-phase (Ni16Si17Nb6) is more passive than the β-matrix and seems to contribute to a lower steady-state corrosion rate.

  9. Air pollution control systems in WtE units: an overview.

    PubMed

    Vehlow, J

    2015-03-01

    All WtE (waste-to-energy) plants, based on combustion or other thermal processes, need an efficient gas cleaning for compliance with legislative air emission standards. The development of gas cleaning technologies started along with environment protection regulations in the late 1960s. Modern APC (air pollution control) systems comprise multiple stages for the removal of fly ashes, inorganic and organic gases, heavy metals, and dioxins from the flue gas. The main technologies and devices used for abatement of the various pollutants are described and their basic principles, their peculiarities, and their application are discussed. Few systems for cleaning of synthesis gas from waste gasification plants are included. Examples of APC designs in full scale plants are shown and cautious prospects for the future development of APC systems are made. PMID:25022549

  10. Recrystallization of plane strain compressed Al-1 wt.% Mn alloy single crystals of typical unstable orientations.

    PubMed

    Bijak, M; Paul, H; Driver, J H

    2010-03-01

    A systematic study of crystal lattice reorientation in early stages of recrystallization has been carried out to correlate the orientations of recrystallization nuclei with the deformation microtexture and with slip systems. Microstructure and texture of Al-1 wt.% Mn single crystals of unstable initial orientations of {112}111, {100}001 and {001}110 have been examined by high-resolution field-emission gun scanning electron microscope local orientation measurements. All single crystals were channel-die deformed at room temperature and then annealed for a short time. It was shown that often observed presence of the 112 directions as rotation axes in the formation of new nuclei orientation directly suggested a close link with the deformation process. PMID:20500369

  11. The /beta/ to /alpha/ transformation in a Zr-2. 5 wt% Nb alloy

    SciTech Connect

    Perovic, V.; Weatherly, G.C.

    1989-03-01

    The /beta/ (b.c.c.) to /alpha/ (h.c.p.) phase transformation in a Zr-2.5 wt% Nb alloy has been studied by transmission electron microscopy. The complex arrays of dislocations observed at the chi//beta/ interface were associated with slip on (T011)/sub H/ planes and interactions of dislocations with the array. The dislocations lay parallel to the invariant line of the phase transformation which corresponded closely to the intersections of (1011)/sub H/. (101)/sub B/ with the cone of unextended lines of the transformation. The interactions between and dislocations at the interface were analyzed by considering the similarities between step formation at tilt boundaries in single phase alloys and those found at the chi/beta/ interface in the present alloy.

  12. Analysis of irradiated U-7wt%Mo dispersion fuel microstructures using automated image processing

    NASA Astrophysics Data System (ADS)

    Collette, R.; King, J.; Buesch, C.; Keiser, D. D.; Williams, W.; Miller, B. D.; Schulthess, J.

    2016-07-01

    The High Performance Research Reactor Fuel Development (HPPRFD) program is responsible for developing low enriched uranium (LEU) fuel substitutes for high performance reactors fueled with highly enriched uranium (HEU) that have not yet been converted to LEU. The uranium-molybdenum (U-Mo) fuel system was selected for this effort. In this study, fission gas pore segmentation was performed on U-7wt%Mo dispersion fuel samples at three separate fission densities using an automated image processing interface developed in MATLAB. Pore size distributions were attained that showed both expected and unexpected fission gas behavior. In general, it proved challenging to identify any dominant trends when comparing fission bubble data across samples from different fuel plates due to varying compositions and fabrication techniques. The results exhibited fair agreement with the fission density vs. porosity correlation developed by the Russian reactor conversion program.

  13. XRMON-SOL: Isothermal equiaxed solidification of a grain refined Al-20 wt%Cu alloy

    NASA Astrophysics Data System (ADS)

    Murphy, A. G.; Mathiesen, R. H.; Houltz, Y.; Li, J.; Lockowandt, C.; Henriksson, K.; Zimmermann, G.; Melville, N.; Browne, D. J.

    2016-04-01

    A novel isothermal solidification furnace (XRMON-SOL) has been developed for operation under terrestrial and microgravity conditions, using aluminium-based alloys, in conjunction with real-time in situ X-radiography. The furnace is scheduled to fly on board the MASER 13 Sounding Rocket with a view to investigating isothermal equiaxed solidification under microgravity conditions. The present work provides details of the furnace design as well as detailed analysis of pre-flight terrestrial solidification experiments investigating nucleation and growth characteristics of a thin sample of grain refined Al-20 wt%Cu alloy isothermally solidified at a constant cooling rate of -0.05 K/s. Measurements of nucleation density, nucleation undercooling, grain orientation, grain envelope evolution, primary tip growth velocities, and equiaxed grain interactions are provided. Although the effects of gravity were minimised by choice of sample orientation, we show that such effects can only be eliminated in a microgravity environment.

  14. Isothermal age-hardening behaviour in a Au-1.6 wt% Ti alloy.

    PubMed

    Kim, H I; Seol, H J; Bae, D H; Shim, J Y; Takada, Y; Okuno, O

    1999-03-01

    This study describes research with a view to developing a new age-hardenable, high-carat dental gold alloy with better biocompatibility by addition of a small quantity of titanium to gold. The relationship between isothermal age-hardening and phase transformation of the Au-1.6 wt% Ti alloy was investigated by means of hardness testing, X-ray diffraction study, scanning electron microscopic observation and energy dispersive spectroscopy. The hardening in the initial stage of ageing seemed to be attributable to the continuous precipitation of the Au4Ti ordered phase in the supersaturated alpha solid solution matrix. The overaging with softening was attributed mainly to the formation of precipitates at the grain boundaries, which grew to bright lamellae and seemed to be composed of the Au4Ti phase. PMID:10786146

  15. Effect of heat treatments on discontinuous precipitation kinetics in Al-30 wt.% Zn alloy

    SciTech Connect

    Boumerzoug, Z.; Fatmi, M.

    2009-08-15

    The discontinuous precipitation kinetics in Al-30% wt. Zn alloy have been investigated at temperatures ranging from 348 to 503 K (75 to 230 deg. C) by using an optical microscopy, X-ray diffraction, differential dilatometer, differential scanning calorimetry and microhardness measurement. We have found that at all temperatures less than 180 deg. C the supersaturated solid solution of quenched alloy was observed to decompose completely by a cellular precipitation reaction. Quantitative metallography methods have been applied to measure the corresponding transformed volume fractions at different temperatures and times of precipitation. The variation of the heating rate and the application of different methods have allowed us to calculate two kinetic parameters of precipitation: the activation energy of the process and the Avrami exponent.

  16. Relation between surface slip topography and stress corrosion cracking in Ti-8 wt % Al

    NASA Technical Reports Server (NTRS)

    Boyd, J. D.; Hoagland, R. G.

    1974-01-01

    The deformation behavior of Ti-8 wt % Al has been investigated in an inert environment (air), and an aggressive environment (salt water). Details of surface slip geometry were examined by high resolution surface replicas at various stages of deformation in both environments. Specimens aged to contain a fine dispersion of Ti3Al precipitates failed by subcritical crack growth in salt water, whereas specimens in the single phase condition showed no effects of environment on the yield or fracture characteristics. The Ti3Al precipitates produce little change in strength level or slip character compared to the single phase alloy, and there is no evidence of any effects of environment on the character of surface slip. Rather, the presence of trenches along slip bands on the surface of aged specimens suggest that the specific effect of the Ti3Al precipitates is to render the surface slip steps chemically active relative to the surrounding matrix by slip induced dissolution of the particles.

  17. Revisiting scoliosis in the KNM-WT 15000 Homo erectus skeleton.

    PubMed

    Schiess, Regula; Boeni, Thomas; Rühli, Frank; Haeusler, Martin

    2014-02-01

    Owing to its completeness, the 1.5 million year old Nariokotome boy skeleton KNM-WT 15000 is central for understanding the skeletal biology of Homo erectus. Nevertheless, since the reported asymmetries and distortions of Nariokotome boy's axial skeleton suggest adolescent idiopathic scoliosis, possibly associated with congenital skeletal dysplasia, it is questionable whether it still can be used as a reference for H. erectus. Recently, however, the presence of skeletal dysplasia has been refuted. Here, we present a morphological and morphometric reanalysis of the assertion of idiopathic scoliosis. We demonstrate that unarticulated vertebral columns of non-scoliotic and scoliotic individuals can be distinguished based on the lateral deviation of the spinous process, lateral and sagittal wedging, vertebral body torsion, pedicle thickness asymmetry, and asymmetry of superior and inferior articular facet areas. A principal component analysis of the overall asymmetry of all seven vertebral shape variables groups KNM-WT 15000 within non-scoliotic modern humans. There is, however, an anomaly of vertebrae T1-T2 that is compatible with a short left convex curve at the uppermost thoracic region, possibly due to injury or local growth dysbalance. Asymmetries of the facet joints L3-L5 suggest a local right convex curve in the lower lumbar region that probably resulted from juvenile traumatic disc herniation. This pattern is incompatible with adolescent idiopathic scoliosis or other types of scoliosis, including congenital, neuromuscular or syndromic scoliosis. It is, however, consistent with a recent reanalysis of the rib cage that did not reveal any asymmetry. Except for these possibly trauma-related anomalies, the Nariokotome boy fossil therefore seems to belong to a normal H. erectus youth without evidence for adolescent idiopathic scoliosis or other severe pathologies of the axial skeleton. PMID:24491377

  18. The chimeric EWS-WT1 gene product in the desmoplastic small round cell tumor: Molecular detection and alternative transcripts

    SciTech Connect

    Gerald, W.; Alava, E. de; Ladanyi, M.

    1994-09-01

    The desmoplastic small round cell tumor (DSRCT) is a recently recognized aggressive type of primitive sarcoma occurring mainly in young males. Previous cytogenetic reports have identified a recurrent translocation in DSRCT, t(11;22)(p13;q12). We have recently shown that this translocation represents a rearrangement between the EWS and WT1 genes, normally located at 22q12 and 11p13, respectively, generating a fusion gene which encodes a chimeric RNA resulting from an in-frame junction of EWS exon 7 to WT1 exon 8. Thus, this chimeric RNA encodes a putative protein in which the RNA-binding domain of EWS is replaced by the three C-terminal zinc fingers of the WT1 DNA-binding domain. We have now assessed the molecular detection of this rearrangement in a panel of 7 DSRCTs and 38 other small round cell tumors, and we have examined the WT1 portion of the chimeric RNA for the presence of the previously reported splice variants of the zinc-finger DNA-binding domain of WT1. Reverse transcriptase PCR (RT-PCR) revealed a single identical product in 4/5 cases tested, including a case in which a t(11;22)(p13;q12) by karyotyping. By Southern blotting, rearrangement of both EWS and WT1 was detectable in 3/6 cases, EWS alone in 1/6, and neither in 2/6. Histologically, the sole sample negative by both methods contained very scanty viable tumor. EWS-WT1 RT-PCR was negative in 16 Wilms` tumors, 12 rhadomyosarcomas, and 10 Ewing`s sarcomas. RT-PCR with splice site-specific primers showed the chimeric EWS-WT1 transcripts to include both splice variants of the zinc-finger domain of WT1, {open_quotes}+KTS{close_quotes} and {open_quotes}-KTS{close_quotes}. The t(11;22)(p13;q12) of DSRCT is most reliably detected by RT-PCR, and results in a specific and structurally highly consistent EWS-WT1 chimeric transcript which may interact with the normal targets of both splice variants of WT1.

  19. TTP SR1-6-WT-31, Milestone C.3-2 Annual Report on Clemson/INEEL Melter Work

    SciTech Connect

    Bickford, D.F.

    1999-10-20

    This work is performed in collaboration with RL37WT31-C and ID77WT31-B. During the first two years of radioactive operation of the DWPF process, several areas for improvement in melter design have been identified. The continuing scope of this task is to address performance limitations and deficiencies identified by the user. SRS will design and test several configurations of the melter pour spout and associated equipment to improve consistency of performance and recommend design improvements.

  20. Expression of the Wilms' tumour gene WT1 in the developing human and in paediatric renal tumours: an immunohistochemical study.

    PubMed Central

    Charles, A. K.; Mall, S.; Watson, J.; Berry, P. J.

    1997-01-01

    AIMS: The Wilms' tumour gene (WT1) product is expressed during the development of the urogenital system. This study was undertaken to evaluate four anti-WT1 antibodies and use the most specific one to examine the expression of WT1 in formalin fixed, paraffin wax embedded tissues from human embryos, fetuses, and paediatric renal neoplasms. METHODS: The antibodies were assessed on paraffin sections of fetal kidney and by western blotting. Immunohistochemical techniques were optimised and performed on a range of embryonic, fetal, and infant tissues from 35 days post-conception to three months of age, and on a selection of paediatric renal neoplasms. RESULTS: The antibodies tested were found to vary in their specificity. Anomalous expression in smooth muscle was seen with one batch of a commercial polyclonal antibody. WT1 protein was detected in both the metanephros and the mesonephros, the spleen, the gonads, and in the peritoneal mesothelium in fetuses. WT1 was expressed in nuclei and was strongest in the podocytes of fetal kidney. The podocytes of infant glomeruli were also positive. There was focal positive staining in Wilms' tumours, nephrogenic rests, and in a cystic partially differentiated nephroblastoma. Staining of nuclei was seen in one of two rhabdoid tumours of the kidney. No positive staining was seen in other renal tumours. CONCLUSIONS: WT1 is detected readily in formalin fixed material. There were differences in specificity between batches of the polyclonal antibodies used. The distribution of the WT1 gene product in tissues and tumours reflected previous findings with in situ hybridisation studies of WT1 mRNA. Images PMID:9292148

  1. Review of PGDP assessment of criticality safety problems in increasing product assay to 5 wt % /sup 235/U

    SciTech Connect

    Petrie, L.M.; Turner, J.C.; Stewart, G.B.

    1985-02-01

    Paducah Gaseous Diffusion Plant (PGDP) performed an evaluation of the PGDP facilities to determine the feasibility of increasing product assay from 2.0 wt % to 5.0 wt % /sup 235/U and to determine the impact of this increase on plant criticality safety; their conclusions are reported in KY-710. This report critiques the methods used and conclusions reached in KY-710. 4 figures, 5 tables.

  2. Crystallization Kinetics of Fe76.5- x C6.0Si3.3B5.5P8.7Cu x ( x = 0, 0.5, and 1 at. pct) Bulk Amorphous Alloy

    NASA Astrophysics Data System (ADS)

    Jung, Hyo Yun; Stoica, Mihai; Yi, Seonghoon; Kim, Do Hyang; Eckert, Jürgen

    2015-06-01

    The influence of Cu on crystallization kinetics of Fe76.5- x C6.0Si3.3B5.5P8.7Cu x ( x = 0, 0.5, and 1 at. pct) bulk amorphous alloys was investigated by isothermal and isochronal differential scanning calorimetry combined with X-ray diffraction. The thermal analysis revealed that the crystallization of the amorphous matrix proceeds through at least two exothermic events. The Cu-free glassy alloy forms by primary crystallization the metastable Fe23C6 phase, while upon 0.5 at. pct Cu addition the primary crystallized phase is α-Fe. The activation energy for crystallization, calculated using both Kissinger and Ozawa methods, decreases from about 500 kJ/mol to about 330 kJ/mol. Further increase of Cu addition to 1 at. pct promotes the concomitant crystallization of several phases, as α-Fe, FeB, Fe3C, and Fe2P. In order to understand the crystallization behavior of the alloys as a function of Cu content, the Avrami exponent n, evaluated from the Johnson-Mehl-Avrami equation, was in details analyzed. The current study reveals that the minor Cu addition plays a crucial role at the initial stage of the crystallization. Among the studied alloys, the glassy samples with 0.5 at. pct Cu addition have the optimum compositional condition for the single α-Fe formation with a high nucleation rate.

  3. Growth of aluminum-free porous oxide layers on titanium and its alloys Ti-6Al-4V and Ti-6Al-7Nb by micro-arc oxidation.

    PubMed

    Duarte, Laís T; Bolfarini, Claudemiro; Biaggio, Sonia R; Rocha-Filho, Romeu C; Nascente, Pedro A P

    2014-08-01

    The growth of oxides on the surfaces of pure Ti and two of its ternary alloys, Ti-6Al-4V and Ti-6Al-7Nb, by micro-arc oxidation (MAO) in a pH 5 phosphate buffer was investigated. The primary aim was to form thick, porous, and aluminum-free oxide layers, because these characteristics favor bonding between bone and metal when the latter is implanted in the human body. On Ti, Ti-6Al-4 V, and Ti-6Al-7Nb, the oxides exhibited breakdown potentials of about 200 V, 130 V, and 140 V, respectively, indicating that the oxide formed on the pure metal is the most stable. The use of the MAO procedure led to the formation of highly porous oxides, with a uniform distribution of pores; the pores varied in size, depending on the anodizing applied voltage and time. Irrespective of the material being anodized, Raman analyses allowed us to determine that the oxide films consisted mainly of the anatase phase of TiO2, and XPS results indicated that this oxide is free of Al and any other alloying element. PMID:24907769

  4. Expression analysis and localization of wt1, ad4bp/sf-1 and gata4 in the testis of catfish, Clarias batrachus: Impact of wt1-esiRNA silencing.

    PubMed

    Murugananthkumar, Raju; Senthilkumaran, Balasubramanian

    2016-08-15

    In teleosts, a comprehensive role or interaction of wt1, ad4bp/sf-1 and gata4 genes in relation to gonadal development and/or recrudescence was never attempted. Present study aimed to identify the involvement of these genes during testicular development of catfish, Clarias batrachus. Dominant expression of wt1 and gata4 was observed in developing and adult testis, while ad4bp/sf-1 showed steady expression. Localization of these genes in adult testis revealed their presence in spermatogonia, spermatocytes and interstitial/Leydig cells. Significant high expression during pre-spawning and spawning phases, and upregulated levels of these genes after hCG induction authenticated gonadotropic regulation. Transient silencing of wt1-esiRNA displayed decrease in wt1 expression, which further downregulated the expression of ad4bp/sf-1 and gata4, and certain steroidogenic enzyme genes related to androgen production. These results suggest that wt1 might target ad4bp/sf-1 and gata4 expression, and also have regulatory influence either indirectly or directly on the steroidogenic enzyme genes of catfish. PMID:27173028

  5. Gravity and magnetic data across the Ghost Dance Fault in WT-2 Wash, Yucca Mountain, Nevada

    SciTech Connect

    Oliver, H.W.; Sikora, R.F.

    1994-12-31

    Detailed gravity and ground magnetic data were obtained in September 1993 along a 4,650 ft-long profile across the Ghost Dance Fault system in WT-2 Wash. Gravity stations were established every 150 feet along the profile. Total-field magnetic measurements made initially every 50 ft along the profile, then remade every 20 ft through the fault zone. These new data are part of a geologic and geophysical study of the Ghost Dance Fault (GDF) which includes detailed geologic mapping, seismic reflection, and some drilling including geologic and geophysical logging. The Ghost Dance Fault is the only through-going fault that has been identified within the potential repository for high-level radioactive waste at Yucca Mountain, Nevada. Preliminary gravity results show a distinct decrease of 0.1 to 0.2 mGal over a 600-ft-wide zone to the east of and including the mapped fault. The gravity decrease probably marks a zone of brecciation. Another fault-offset located about 2,000 ft to the east of the GDF was detected by seismic reflection data and is also marked by a distinct gravity low. The ground magnetic data show a 200-ft-wide magnetic low of about 400 nT centered about 100 ft east of the Ghost Dance Fault. The magnetic low probably marks a zone of brecciation within the normally polarized Topopah Spring Tuff, the top of which is about 170 ft below the surface, and which is known from drilling to extend to a depth of about 1,700 ft. Three-component magnetometer logging in drill hole WT-2 located about 2,700 ft east of the Ghost Dance Fault shows that the Topopah Spring Tuff is strongly polarized magnetically in this area, so that fault brecciation of a vertical zone within the Tuff could provide an average negative magnetic contrast of the 4 Am{sup {minus}1} needed to produce the 400 nT low observed at the surface.

  6. Precipitation under cyclic strain in solution-treated Al4wt%Cu II: precipitation behavior

    SciTech Connect

    Farrow, Adam M; Laird, Campbell

    2008-01-01

    Solution-treated Al-4wt%Cu was strain-cycled at ambient temperature and above, and the precipitation behavior investigated by Transmission Electron Microscopy (TEM). In the temperature range 100{sup o}C to 200{sup o}C, precipitation of {Theta}' appears to have been suppressed, and precipitation of theta-prime promoted. Anomalously rapid growth of precipitates appears to have been facilitated by a vacancy super-saturation generated by cyclic strain, with a diminishing effect observed at higher temperatures due to the recovery of non-equilibrium vacancy concentrations. The {Theta}' precipitates generated under cyclic strain are considerably smaller and more finely dispersed than those typically produced via quench-aging due to their heterogeneous nucleation on disloctions, and possess a low aspect ratio and rounded edges of the broad faces, due to the introduction of ledges into the growing precipitates by dislocation cutting. Frequency effects indicate that dislocation motion, rather than extremely small precipitate size, is responsible for the reduction in aspect ratio.

  7. Precipitation in solution-treated Al-4wt%Cu under cyclic strain

    SciTech Connect

    Farrow, Adam M; Laird, Campbell

    2010-09-15

    Solution-treated Al-4wt%Cu was strain-cycled at ambient temperature and above and the precipitation behavior investigated by TEM. In the temperature range 100 C to 200 C precipitation of {Theta}'' appears to have been suppressed and precipitation of {Theta}' promoted via cyclic strain. Anomalously rapid growth of precipitates appears to have been facilitated by a vacancy supersaturation generated by dislocation motion, with a diminishing effect observed at higher temperatures due to the faster recovery of non-equilibrium vacancy concentrations. {Theta}' precipitates generated under cyclic strain are considerably smaller and more finely dispersed than those typically produced via quench-aging due to their heterogeneous nucleation on dislocations, and possess a low aspect ratio and rounded edges of the broad faces due to the introduction of ledges into the growing precipitates by dislocation cutting. Frequency effects indicate that dislocation motion, rather than the extremely small precipitate size, is responsible for the observed reduction in aspect ratio. Accelerated formation of grain boundary precipitates appears partially responsible for rapid intergranular fatigue failure following cycling at elevated temperatures, producing fatigue striations and ductile dimples coexistent on the fracture surface.

  8. Precipitation under cyclic strain in solution-treated Al4wt%Cu I: mechanical behavior

    SciTech Connect

    Farrow, Adam M; Laird, Campbell

    2008-01-01

    Solution-treated AL-4wt%Cu was strain-cycled at ambient temperature and above, and the precipitation and deformation behaviors investigated by TEM. Anomalously rapid growth of precipitates appears to have been facilitated by a vacancy super-saturation generated by cyclic strain and the presence of a continually refreshed dislocation density to provide heterogeneous nucleation sites. Texture effects as characterized by Orientation Imaging Microscopy appear to be responsible for latent hardening in specimens tested at room temperature, with increasing temperatures leading to a gradual hardening throughout life due to precipitation. Specimens exhibiting rapid precipitation hardening appear to show a greater effect of texture due to the increased stress required to cut precipitates in specimens machined from rolled plate at an angle corresponding to a lower average Schmid factor. The accelerated formation of grain boundary precipitates appears to be partially responsible for rapid inter-granular fatigue failure at elevated temperatures, producing fatigue striations and ductile dimples coexistent on the fracture surface.

  9. Structural changes in Bi-43 wt % Sn eutectic alloy under superplastic deformation

    NASA Astrophysics Data System (ADS)

    Korshak, V. F.; Shapovalov, Yu. A.; Prymak, O.; Kryshtal, A. P.; Vasilenko, R. L.

    2015-08-01

    Methods of scanning electron microscopy have been used to study the microstructure of superplastically deformed samples of eutectic alloy Bi-43 wt % Sn. The observed specific features of the deformation relief of the samples reveal the active development of the viscous dislocation-diffusion flow under superplasticity conditions. The manifestation of the hydrodynamic mode of deformation has been revealed under these conditions. The opportunity of the realization of viscous mechanisms of the transport of substance and of the manifestation of the effect of superplasticity are explained by the appearance in the material of a state that is characterized by a high dislocation density and low strength properties. An additional increase in the dislocation density and softening under superplasticity conditions are attributed to the occurrence of structural and phase transformations stimulated by deformation, the relaxation of significant internal elastic stresses, and the instability of the structural state of the initially nonequilibrium alloy in the field of mechanical stresses. Factors responsible for the appearance of significant internal elastic stresses in the alloy are analyzed.

  10. Properties of WZ21 (%wt) alloy processed by a powder metallurgy route.

    PubMed

    Cabeza, Sandra; Garcés, Gerardo; Pérez, Pablo; Adeva, Paloma

    2015-06-01

    Microstructure, mechanical properties and corrosion behaviour of WZ21 (%wt) alloy prepared by a powder metallurgy route from rapidly solidified powders have been studied. Results were compared to those of the same alloy prepared through a conventional route of casting and extrusion. The microstructure of the extruded ingot consisted of α-Mg grains and Mg3Zn3Y2 (W-phase) and LPSO-phase particles located at grain boundaries. Moreover, stacking faults were also observed within α-Mg grains. The alloy processed by the powder metallurgy route exhibited a more homogeneous and finer microstructure, with a grain size of 2 μm. In this case W-phase and Mg24Y5 phase were identified, but not the LPSO-phase. The microstructural refinement induced by the use of rapidly solidified powders strengthened the alloy at room temperature and promoted superplasticity at higher strain rates. Corrosion behaviour in PBS medium evidenced certain physical barrier effect of the almost continuous arrangements of second phases aligned along the extrusion direction in conventionally processed WZ21 alloy, with a stable tendency around 7 mm/year. On the other hand, powder metallurgy processing promoted significant pitting corrosion, inducing accelerated corrosion rate during prolonged immersion times. PMID:25792409

  11. Microstructural, mechanical, corrosion and cytotoxicity characterization of the hot forged FeMn30(wt.%) alloy.

    PubMed

    Čapek, Jaroslav; Kubásek, Jiří; Vojtěch, Dalibor; Jablonská, Eva; Lipov, Jan; Ruml, Tomáš

    2016-01-01

    An interest in biodegradable metallic materials has been increasing in the last two decades. Besides magnesium based materials, iron-manganese alloys have been considered as possible candidates for fabrication of biodegradable stents and orthopedic implants. In this study, we prepared a hot forged FeMn30 (wt.%) alloy and investigated its microstructural, mechanical and corrosion characteristics as well as cytotoxicity towards mouse L 929 fibroblasts. The obtained results were compared with those of iron. The FeMn30 alloy was composed of antiferromagnetic γ-austenite and ε-martensite phases and possessed better mechanical properties than iron and even that of 316 L steel. The potentiodynamic measurements in simulated body fluids showed that alloying with manganese lowered the free corrosion potential and enhanced the corrosion rate, compared to iron. On the other hand, the corrosion rate of FeMn30 obtained by a semi-static immersion test was significantly lower than that of iron, most likely due to a higher degree of alkalization in sample surrounding. The presence of manganese in the alloy slightly enhanced toxicity towards the L 929 cells; however, the toxicity did not exceed the allowed limit and FeMn30 alloy fulfilled the requirements of the ISO 10993-5 standard. PMID:26478385

  12. Primary arm spacing in directionally solidified Pb-10 wt percent Sn alloys

    NASA Technical Reports Server (NTRS)

    Chopra, M. A.; Tewari, S. N.

    1990-01-01

    The dependence of primary arm spacings on growth speed was investigated for cellular and dendritic arrays in Pb-10 wt percent Sn samples directionally solidified under a constant positive thermal gradient in the melt. The gradient of constitutional supercooling was varied from almost zero (near the break-down of the planar liquid-solid interface at small growth speeds, cellular morphology) to near unity (large growth speeds, dendritic morphology). The spatial arrangements of cells and dendrites, as given by their coordination number, are not very different from each other. It appears that primary arm spacing maxima and the cell to dendrite transition are strongly influenced by the magnitude of the solute partition coefficient. The planar to cellular bifurcation is supercritical in Pb-Sn which has a high partition coefficient, as compared to the subcritical behavior reported in Al-Cu and succinonitrile-acetone, both of which have low partition coefficients. The primary arm spacing model due to Hunt agrees with the experimentally observed trend for the whole growth regime. There is a good quantitative agreement at higher gradients of supercooling. However, the model overpredicts the primary arm spacings at low gradients of constitutional supercooling.

  13. Subcritical bifurcation from planar to cellular interface in Al-0.5 wt% Cu directionally solidified

    SciTech Connect

    Fornaro, O.; Palacio, H.; Biloni, H.

    1998-12-31

    Samples of the Al-0.5 wt% Cu system were directionally grown under controlled conditions, to study the role played by the instabilities in the process relatives to the microstructure selection for a given value of interface velocity, and thermal gradient. Using an interface quenching technique and metallographic analysis in longitudinal and transversal cuts of the samples, the authors determine the transition mechanism between the different stages of the growth, and associate them to the stability of the solidification front. They study the planar to a cellular transition in different conditions, and although the solidification parameters are in good agreement with the perturbation theory, when analyzing the amplitude of the perturbations during the planar to a cellular transition, the same theory is not able to predict certainly the critical wavelength in this case., Also, they found a subcritical behavior during the transition from a planar to a cellular interface for the diluted Al-Cu system, detecting a hysteresis behavior for the amplitude of the perturbations when it is increasing and then decreasing the interface velocity, through the threshold.

  14. Thermal treatment of solid residues from WtE units: A review

    SciTech Connect

    Lindberg, Daniel Molin, Camilla Hupa, Mikko

    2015-03-15

    Highlights: • We review the thermal treatment methods for ashes and residues from WtE plants. • We review the results from extensive laboratory work on vitrification, melting and vaporization of ash. • We analyze the results from the extensive patent literature on thermal treatment. • We review industrial concepts for thermal treatment of ash. - Abstract: Thermal treatment methods of bottom ash, fly ash and various types of APC (air pollution control) residues from waste-to-energy plants can be used to obtain environmentally stable material. The thermal treatment processes are meant to reduce the leachability of harmful residue constituents, destroy toxic organic compounds, reduce residue volume, and produce material suitable for utilization. Fly ash and APC residues often have high levels of soluble salts, particularly chlorides, metals such as cadmium, lead, copper and zinc, and trace levels of organic pollutants such as dioxins and furans. Different thermal treatment methods can be used to either decompose or stabilize harmful elements and compounds in the ash, or separate them from the ash to get a material that can be safely stored or used as products or raw materials. In the present paper, thermal treatment methods, such as sintering, vitrification, and melting have been reviewed. In addition to a review of the scientific literature, a survey has been made of the extensive patent literature in the field.

  15. Air pollution control systems in WtE units: An overview

    SciTech Connect

    Vehlow, J.

    2015-03-15

    Highlights: • The paper describes in brief terms the development of gas cleaning in waste incineration. • The main technologies for pollutant removal are described including their basic mechanisms. • Their respective efficiencies and their application are discussed. • A cautious outlook regarding future developments is made. - Abstract: All WtE (waste-to-energy) plants, based on combustion or other thermal processes, need an efficient gas cleaning for compliance with legislative air emission standards. The development of gas cleaning technologies started along with environment protection regulations in the late 1960s. Modern APC (air pollution control) systems comprise multiple stages for the removal of fly ashes, inorganic and organic gases, heavy metals, and dioxins from the flue gas. The main technologies and devices used for abatement of the various pollutants are described and their basic principles, their peculiarities, and their application are discussed. Few systems for cleaning of synthesis gas from waste gasification plants are included. Examples of APC designs in full scale plants are shown and cautious prospects for the future development of APC systems are made.

  16. Three-dimensional reconstruction of anomalous eutectic in laser remelted Ni-30 wt.% Sn alloy

    NASA Astrophysics Data System (ADS)

    Cao, Yong-Qing; Lin, Xin; Wang, Zhi-Tai; Wang, Li-Lin; Song, Meng-Hua; Yang, Hai-Ou; Huang, Wei-Dong

    2015-12-01

    Laser remelting has been performed on Ni-30 wt.% Sn hypoeutectic alloy. An anomalous eutectic formed at the bottom of the molten pool when the sample was remelted thoroughly. 3D morphologies of the α-Ni and Ni3Sn phases in the anomalous eutectic region were obtained and investigated using serial sectioning reconstruction technology. It is found that the Ni3Sn phase has a continuous interconnected network structure and the α-Ni phase is distributed as separate particles in the anomalous eutectic, which is consistent with the electron backscatter diffraction pattern examinations. The α-Ni particles in the anomalous eutectic are supersaturated with Sn element as compared with the equilibrium phase diagram. Meanwhile, small wavy lamella eutectics coexist with anomalous eutectics. The Trivedi-Magnin-Kurz model was used to estimate undercooling with lamellar spacing. The results suggest that the critical undercooling found in undercooling solidification is not a sufficient condition for anomalous eutectic formation. Besides, α-Ni particles in the anomalous eutectic do not exhibit a completely random misorientation and some neighboring α-Ni particles have the same orientation. It is shown that both the coupled and decoupled growth of the eutectic two phases can generate the α-Ni + Ni3Sn anomalous eutectic structure.

  17. Method for improving the mechanical properties of uranium-1 to 3 wt % zirconium alloy

    DOEpatents

    Anderson, R.C.

    1983-11-22

    A uranium-1 to 3 wt % zirconium alloy characterized by high strength, high ductility and stable microstructure is fabricated by an improved thermal mechanical process. A homogenous ingot of the alloy which has been reduced in thickness of at least 50% in the two-step forging operation, rolled into a plate with a 75% reduction and then heated in vacuum at a temperature of about 750 to 850/sup 0/C and then quenched in water, is subjected to further thermal-mechanical operation steps to increase the compressive yield strength approximately 30%, stabilize the microstructure, and decrease the variations in mechanical properties throughout the plate is provided. These thermal-mechanical steps are achieved by cold rolling the quenchd plate to reduce the thickness thereof about 8 to 12%, aging the cold rolled plate at a first temperature of about 325 to 375/sup 0/C for five to six hours and then aging the plate at a higher temperature ranging from 480 to 500/sup 0/C for five to six hours prior to cooling the billet to ambient conditions and sizing the billet or plate into articles provides the desired increase in mechanical properties and phase stability throughout the plate.

  18. Tribological Analysis of Copper-Coated Graphite Particle-Reinforced A359 Al/5 wt.% SiC Composites

    NASA Astrophysics Data System (ADS)

    Lin, C. B.; Wang, T. C.; Chang, Z. C.; Chu, H. Y.

    2013-01-01

    Copper-coated graphite particles can be mass-produced by the cementation process using simple equipment. Graphite particulates that were coated with electroless copper and 5 wt.% SiC particulates were introduced into an aluminum alloy by compocasting to make A359 Al/5 wt.% SiC(p) composite that contained 2, 4, 6, and 8 wt.% graphite particulate composite. The effects of SiC particles, quantity of graphite particles, normal loading, sliding speed and wear debris on the coefficient of friction, and the wear rate were investigated. The results thus obtained indicate that the wear properties were improved by adding small amounts of SiC and graphite particles into the A359 Al alloy. The coefficient of friction of the A359 Al/5 wt.% SiC(p) composite that contained 6.0 wt.% graphite particulates was reduced to 0.246 and the amount of graphite film that was released on the worn surface increased with the graphite particulate content. The coefficient of friction and the wear rate were insensitive to the variation in the sliding speed and normal loading.

  19. 20 CFR 645.125 - What are the roles of the local and State governmental partners in the governance of the WtW...

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... governmental partners in the governance of the WtW program? 645.125 Section 645.125 Employees' Benefits... governance of the WtW program? (a) Local boards or alternate administering agencies, in coordination with CEO... the WtW statute to the extent that such policies, interpretations, guidelines and definitions are...

  20. Molecular Dynamics Analysis of Binding of Kinase Inhibitors to WT EGFR and the T790M Mutant.

    PubMed

    Park, Jiyong; McDonald, Joseph J; Petter, Russell C; Houk, K N

    2016-04-12

    Epidermal growth factor receptor (EGFR) inhibitors interrupt EGFR-dependent cellular signaling pathways that lead to accelerated tumor growth and proliferation. Mutation of a threonine in the inhibitor binding pocket, known as the "gatekeeper", to methionine (T790M) confers acquired resistance to several EGFR-selective inhibitors. We studied interactions between EGFR inhibitors and the gatekeeper residues of the target protein. Thermodynamic integration (TI) with Amber14 indicates that the binding energies of gefitinib and AEE788 to the active state of the T790M mutant EGFR is 3 kcal/mol higher than to the wild type (WT), whereas ATP binding energy to the mutant is similar to the WT. Using metadynamics MD simulations with NAMD v2.9, the conformational equilibrium between the inactive resting state and the catalytically competent activate state was determined for the WT EGFR. When combined with the results obtained by Sutto and Gervasio, our simulations showed that the T790M point mutation lowers the free energy of the active state by 5 kcal/mol relative to the inactive state of the enzyme. Relative to the WT, the T790M mutant binds gefitinib more strongly. The T790M mutation is nevertheless resistant due to its increased binding of ATP. By contrast, the binding of AEE788 to the active state causes a conformational change in the αC-helix adjacent to the inhibitor binding pocket, that results in a 2 kcal/mol energy penalty. The energy penalty explains why the binding of AEE788 to the T790M mutant is unfavorable relative to binding to WT EGFR. These results establish the role of the gatekeeper mutation on inhibitor selectivity. Additional molecular dynamics (MD) simulations, TI, and metadynamics MD simulations reveal the origins of the changes in binding energy of WT and mutants. PMID:27010480

  1. Characterisation of ATRX, DMRT1, DMRT7 and WT1 in the platypus (Ornithorhynchus anatinus).

    PubMed

    Tsend-Ayush, Enkhjargal; Lim, Shu Ly; Pask, Andrew J; Hamdan, Diana Demiyah Mohd; Renfree, Marilyn B; Grützner, Frank

    2009-01-01

    One of the most puzzling aspects of monotreme reproductive biology is how they determine sex in the absence of the SRY gene that triggers testis development in most other mammals. Although monotremes share a XX female/XY male sex chromosome system with other mammals, their sex chromosomes show homology to the chicken Z chromosome, including the DMRT1 gene, which is a dosage-dependent sex determination gene in birds. In addition, monotremes feature an extraordinary multiple sex chromosome system. However, no sex determination gene has been identified as yet on any of the five X or five Y chromosomes and there is very little knowledge about the conservation and function of other known genes in the monotreme sex determination and differentiation pathway. We have analysed the expression pattern of four evolutionarily conserved genes that are important at different stages of sexual development in therian mammals. DMRT1 is a conserved sex-determination gene that is upregulated in the male developing gonad in vertebrates, while DMRT7 is a mammal-specific spermatogenesis gene. ATRX, a chromatin remodelling protein, lies on the therian X but there is a testis-expressed Y-copy in marsupials. However, in monotremes, the ATRX orthologue is autosomal. WT1 is an evolutionarily conserved gene essential for early gonadal formation in both sexes and later in testis development. We show that these four genes in the adult platypus have the same expression pattern as in other mammals, suggesting that they have a conserved role in sexual development independent of genomic location. PMID:19874722

  2. The effect of directionally solidified microstructures on ductility of Fe-6.5wt%Si alloy

    NASA Astrophysics Data System (ADS)

    Liang, Y. F.; Zheng, Z. L.; Lin, J. P.; Ye, F.; Chen, G. L.

    2009-01-01

    Fe-6.5wt%Si high silicon steel has superior magenitic properties. However, such high Si content results inroom-temperature embrittlement and poor workability due to the formation of ordered intermetallic phases. Zone Melting Liquid Metal Cooling directional solidification technique was employed to produce the Fe-6.5wt%Si alloy with columnar-grained structures. The cooling rate of directional solidificationplays a critical role in maintaining the grain growth, and the rate around 3 K/s is an optimum conditionto form columnar-grained structure and to improve its ductility.

  3. Single-crystal Elasticity of Wadsleyite With 1.7 wt % H 2 O to 11 GPa by Brillouin Scattering

    NASA Astrophysics Data System (ADS)

    Xie, L.; Mao, Z.; Jacobsen, S. D.; Jiang, F.; Smyth, J. R.; Holl, C. M.; Duffy, T. S.

    2008-12-01

    Polymorphs of olivine have the greatest water storage capacity among all the nominally anhydrous mantle minerals (e.g. Bolfan-Casanova et al., 2000). Wadsleyite (β-Mg 2SiO 4) is able to contain up to 3.3 wt% H2O (Smyth et al., 1987). This phase is considered as the dominate mineral in the mantle from 410 km to 520 km depth. A previous study showed that water decreases the elasticity of wadsleyite strongly at ambient conditions (Mao et al., 2008), but has no detectable effect on the pressure derivatives of the bulk and shear moduli of wadsleyite containing 0.84 wt% H2O (Mao et al., in press). The effect of H 2O content on high-pressure elasticity has not been investigated for samples with larger water contents. In this study, we performed high-pressure Brillouin measurements on a single crystal of wadsleyite with 1.7 wt% H2O to obtain the elastic tensor, hence the aggregate elastic moduli and their pressure derivatives. Two crystals were cut and polished into 30~40μm-thick platelets. Single- crystal x-ray diffraction was conducted at x17C of Brookhaven National Laboratory to determine the orientations of the two platelets. The samples were measured at 7 pressures steps up to 11 GPa. For each platelet, 19 spectra were collected at 10° intervals at each pressure step in order to cover a range of 180° degrees. Preliminary result shows that the elastic constants, Cij, have the similar trends as anhydrous and 0.84 wt%-H2O wadsleyite while increasing pressure. Pressure derivatives of bulk and shear moduli are 4.1 (2) and 1.3 (1) for 1.7 wt%-H2O wadsleyite, which are not different within uncertainty from those of anhydrous and 0.84 wt%-H2O wadsleyite. (Zha et al., 1997; Mao et al., in press). This suggests that the pressure derivatives of elastic moduli do not change with water content at least up to 1.7 wt% H2O. It further confirms the previous inference that at least 1 wt% H2O in wadsleyite at 410 km is required for a pyrolite composition (60 vol% olivine) to match

  4. The Effect of Temperature, Specimen Size, and Geometry on the Fracture Toughness of a 3 Pct NiCrMoV Low Pressure Turbine Disc Steel

    NASA Astrophysics Data System (ADS)

    Shaw, N. B.; Spink, G. M.

    1983-03-01

    The variation of fracture toughness with temperature and specimen size of a 3 pct NiCrMoV LP disc steel has been investigated over the temperature range -100 to +100 °C using compact tension and single-edge-notched bend geometries. A number of large ‘half-disc’ three point bend specimens were also tested. Toughness increased up to a transition temperature coinciding with the onset of stable ductile tearing prior to instability. Below this temperature fracture could be described by established linear elastic or post yield fracture analyses. Above this temperature failure was by plastic collapse. The transition temperature decreased with decreasing specimen size, and at similar thicknesses was lower for the bend geometry than for the compact tension so that it was not possible to predict the fracture behavior of the full size service component from small scale tests in the transition region. A further complicating feature was the extreme scatter of some duplicate test results below the transition temperature. The implications for toughness testing in the transition region are discussed. The data obtained in this work have been combined with published data for similar steels to derive an equation which describes the variation of fracture toughness with temperature for steels of this type.

  5. Dispersion of fine primary inclusions of MgO and ZrO{sub 2} in Fe-10 mass pct Ni alloy and the solidification structure

    SciTech Connect

    Sakata, Kimiaki; Suito, Hideaki

    1999-12-01

    The homogeneous dispersion of primary inclusions of MgO and ZrO{sub 2} was studied in an Fe-10 mass pct Ni alloy as a function of the holding time at 1,873 K and the cooling rate. The spatial size distribution was estimated from the planar size distribution obtained in a cross section by applying the Schwartz-Saltykov transformation. It was found that the content of insoluble Mg or Zr estimated from the size distribution agreed with that obtained from chemical analysis. The influence on the solidification macrostructure such as columnar dendrite, equiaxed dendrite, and globular crystal of dissolved Mg or Zr and inclusion particles having the mean diameter of roughly 1 {micro}m was investigated. The area fraction of globular crystals in the Mg deoxidation decreased with increasing dissolved Mg content ({gt}30 mass ppm) in the presence of MgO particles. In the Zr deoxidation, however, globular crystals were only observed in the presence of ZrO{sub 2} particles without respect to the presence of dissolved Zr.

  6. Human lymphocytes express the transcriptional regulator, Wilms tumor 1: The role of WT1 in mediating nitric oxide-dependent repression of lymphocyte proliferation

    SciTech Connect

    Marcet-Palacios, Marcelo; Davoine, Francis; Adamko, Darryl J.; Moqbel, Redwan; Befus, A. Dean

    2007-11-16

    The inhibitory roles of nitric oxide (NO) in T cell proliferation have been observed and studied extensively over the last two decades. Despite efforts, the fundamental pathway by which NO exerts its inhibitory actions remains to be elucidated although recent evidence suggests that the transcription factor Wilms tumor 1 (WT1) may be important. WT1 has been linked to numerous developmental pathways in particular nephrogenesis. Due to its roles in development and cell proliferation, polymorphisms within the WT1 gene can result in malignancies such as leukemia and Wilms tumor. WT1 functions as a transcriptional regulator and its activity is controlled through phosphorylation by protein kinase A (PKA). PKA-dependent WT1 phosphorylation results in translocation of WT1 from the nucleus to the cytosol, a process that interferes with WT1 transcriptional activities. In the current study we demonstrate that WT1 is expressed in human lymphocytes. Using the proliferative compound PHA we induced T cell proliferation and growth correlated with an increase in the expression of WT1 measured by RT-PCR, flow cytometry and immunoblot. Co-stimulation with the NO donor SNOG at concentrations of 0, 100, 300 and 600 {mu}M reduced in a concentration dependent way the PHA-induced upregulation of WT1 that correlated with a reduction in T cell proliferation. We conclude that WT1 might be an important component of the NO-dependent regulation of T lymphocyte proliferation and potential function.

  7. Pratt & Whitney Advanced Ducted Propulsor (ADP) Engine Test in 40x80ft w.t.: Engineers Peter

    NASA Technical Reports Server (NTRS)

    1993-01-01

    Pratt & Whitney Advanced Ducted Propulsor (ADP) Engine Test in 40x80ft w.t.: Engineers Peter Zell (left) and Dr Clifton Horne (right) are shown preparing a laser light sheet for a flow visualization test. Shown standing in the nacelle of the ADP is John Girvin, senior test engineer for Pratt & Whitney.

  8. Pratt & Whitney Advanced Ducted Propulsor (ADP) Engine Test in 40x80ft w.t.: Engineers Peter

    NASA Technical Reports Server (NTRS)

    1993-01-01

    Pratt & Whitney Advanced Ducted Propulsor (ADP) Engine Test in 40x80ft w.t.: Engineers Peter Zell (left) and Dr Clifton Horne (right) are shown preparing for a laser light sheet for a flow visualization test. Shown standing in the nacelle of the ADP is John Girvin, senior test engineer for Pratt & Whitney.

  9. Research study on materials processing in space experiment number M512: Nickel - 12 wt percent tin alloy evaluation

    NASA Technical Reports Server (NTRS)

    Larson, D. J., Jr.; Chou, H. L.

    1974-01-01

    Nickel-tin (12 wt percent tin) samples were processed in the sphere forming experiment on Skylab 2. The results were characterized for sphericity, density, microhardness, porosity, surface morphology, segregation, chemical composition, Curie point, and crystallography. These results are discussed along with conclusions and recommendations.

  10. NADH interactions with WT- and S94A-acyl carrier protein reductase from Mycobacterium tuberculosis: an ab initio study.

    PubMed

    Pantano, Sergio; Alber, Frank; Lamba, Doriano; Carloni, Paolo

    2002-04-01

    We present an ab initio molecular dynamics study of the complex between acyl carrier protein reductase InhA from M. tuberculosis and isonicotinic acid hydrazide-NADH. We focus on wild-type (WT) InhA and a mutant causing drug resistance (S94A) for which structural information is available (Rozwarski et al., 1998;279:98--102; Dessen et al., 1995;267:1638--1641). Our calculations suggest that the water-mediated H-bond interactions between Ser94 side chain and NADH, present in WT InhA X-ray structure, can be lost during the dynamics. This conformational change is accompanied by a structural rearrangement of Gly14. The calculated structure of WT is rather similar to the X-ray structure of the S94A mutant in terms of geometrical parameters and chemical bonding. Further evidence for the mobility of Ser94 is provided by a 1-ns-long classical molecular dynamics on the entire protein. The previously unrecognized high mobility of Ser94 can provide a rationale of the small change in free binding energies on passing from WT to S94A InhA. PMID:11870865

  11. 20 CFR 645.215 - What must a WtW operating entity that serves noncustodial parent participants do?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... and children who may be at risk of domestic violence, the operating entity must consult with domestic violence prevention and intervention organizations in the development of its WtW project serving... that good cause exists to extend this period. This extension may not extend to a date more than...

  12. WT1 is involved in the Akt-JNK pathway dependent autophagy through directly regulating Gas1 expression in human osteosarcoma cells.

    PubMed

    Mo, Hao; He, Juliang; Yuan, Zhenchao; Mo, Ligen; Wu, Zhenjie; Lin, Xiang; Liu, Bin; Guan, Jian

    2016-09-01

    Macroautophagy (herein termed autophagy) works as a protective mechanism in tumorigenesis and development under metabolic stress condition. Multitudes of genes have been found involved in this process during past decades. In the present study, we report that Wilm's tumor suppressor1 (WT1) is involved in autophagy in osteosarcoma (OS) cells. WT1, a transcription factor with multitude of target genes, expresses in a majority of cancer types. Though wide-ranging effect of WT1 is now well documented, the function of WT1 in tumors remains poorly defined. In this chapter, it is found that high expression of WT1 positively correlates with active autophagy in human osteosarcoma cells. And further study on cell signaling pathway illustrates that Akt/JNK pathway acts as a positive regulator of autophagy induced by WT1. Here, we present evidence that WT1 modulates Akt/JNK signaling pathway mediated autophagy by controlling the expression of growth arrest-specific 1 (Gas1). We show that WT1 is required for Gas1 transcription in osteosarcoma cells. And Gas1 is upregulated followed WT1 overexpression in a time-dependent manner. Loss of Gas1 results in a reduction of WT1-induced autophagy. PMID:27453337

  13. Effect of Heat Treatment on Morphology of Fe-Rich Intermetallics in Hypereutectic Al-Si-Cu-Ni Alloy with 1.26 pct Fe

    NASA Astrophysics Data System (ADS)

    Sha, Meng; Wu, Shusen; Wan, Li; Lü, Shulin

    2013-12-01

    Cobalt is generally considered as the element that can neutralize the negative effects of iron in Al alloys, such as inducing fracture and failure for stress concentration. Nevertheless, Fe-rich intermetallics would be inclined to form coarse plate-like δ-Al4(Fe, Co, Ni)Si2 particles when the content of Fe was high, which could also cause inferior mechanical properties. The dissolution and transformation of δ-Al4(Fe, Co, Ni)Si2 phase in solution heat-treated samples of Al-20Si-1.85Cu-1.05Ni-1.26Fe-1.35Co alloy were studied using optical microscopy, image analysis, and scanning electron microscopy. The effects of solution heat treatment time ranging from 0 to 9 hours at 783.15 K (510 °C) on mechanical properties were also investigated. The coarse plate-like δ-Al4(Fe, Co, Ni)Si2 particles varied slowly through concurrent dissolution along widths and at the plate tips as solution treatment time increased, which could be explained from diffusion-induced grain boundary migration. Solution heat treatment also has an important influence on mechanical properties. The maximum ultimate tensile strength and yield strength after T6 treatment were 258 and 132 MPa, respectively, while the maximum hardness was 131 HB. Compared with those of the samples in the as-cast state, they increased by 53, 42, and 28 pct, respectively. Moreover, δ-Al4(Fe, Co, Ni)Si2 phase, which appears as a coarse plate-like particle in two dimensions, is actually a cuboid in three dimensions. The length of this cuboid is close to the width, while the height is much smaller.

  14. Quadruple wild-type (WT) GIST: defining the subset of GIST that lacks abnormalities of KIT, PDGFRA, SDH, or RAS signaling pathways

    PubMed Central

    Pantaleo, Maria A; Nannini, Margherita; Corless, Christopher L; Heinrich, Michael C

    2015-01-01

    A subset of GISTs lack mutations in the KIT/PDGFRA or RAS pathways and yet retain an intact succinate dehydrogensase (SDH) complex. We propose that these KIT/PDGFRA/SDH/RAS-P WT GIST tumors be designated as quadruple wild-type (WT) GIST. Further molecular and clinicophatological characterization of quadruple WT GIST will help to determine their prognosis as well as assist in the optimization of medical management, including clinical test of novel therapies. PMID:25165019

  15. Quadruple wild-type (WT) GIST: defining the subset of GIST that lacks abnormalities of KIT, PDGFRA, SDH, or RAS signaling pathways.

    PubMed

    Pantaleo, Maria A; Nannini, Margherita; Corless, Christopher L; Heinrich, Michael C

    2015-01-01

    A subset of GISTs lack mutations in the KIT/PDGFRA or RAS pathways and yet retain an intact succinate dehydrogensase (SDH) complex. We propose that these KIT/PDGFRA/SDH/RAS-P WT GIST tumors be designated as quadruple wild-type (WT) GIST. Further molecular and clinicophatological characterization of quadruple WT GIST will help to determine their prognosis as well as assist in the optimization of medical management, including clinical test of novel therapies. PMID:25165019

  16. 45 CFR 286.130 - Does the receipt of Welfare-to-Work (WtW) cash assistance count towards a Tribe's TANF time limit?

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 45 Public Welfare 2 2011-10-01 2011-10-01 false Does the receipt of Welfare-to-Work (WtW) cash... and Processing § 286.130 Does the receipt of Welfare-to-Work (WtW) cash assistance count towards a... as well as the penalty provision at § 286.195(a)(1), WtW cash assistance counts towards a...

  17. 45 CFR 286.130 - Does the receipt of Welfare-to-Work (WtW) cash assistance count towards a Tribe's TANF time limit?

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 45 Public Welfare 2 2010-10-01 2010-10-01 false Does the receipt of Welfare-to-Work (WtW) cash... and Processing § 286.130 Does the receipt of Welfare-to-Work (WtW) cash assistance count towards a... as well as the penalty provision at § 286.195(a)(1), WtW cash assistance counts towards a...

  18. 45 CFR 286.130 - Does the receipt of Welfare-to-Work (WtW) cash assistance count towards a Tribe's TANF time limit?

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 45 Public Welfare 2 2012-10-01 2012-10-01 false Does the receipt of Welfare-to-Work (WtW) cash... and Processing § 286.130 Does the receipt of Welfare-to-Work (WtW) cash assistance count towards a... as well as the penalty provision at § 286.195(a)(1), WtW cash assistance counts towards a...

  19. 45 CFR 286.130 - Does the receipt of Welfare-to-Work (WtW) cash assistance count towards a Tribe's TANF time limit?

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 45 Public Welfare 2 2014-10-01 2012-10-01 true Does the receipt of Welfare-to-Work (WtW) cash... and Processing § 286.130 Does the receipt of Welfare-to-Work (WtW) cash assistance count towards a... as well as the penalty provision at § 286.195(a)(1), WtW cash assistance counts towards a...

  20. 45 CFR 286.130 - Does the receipt of Welfare-to-Work (WtW) cash assistance count towards a Tribe's TANF time limit?

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 45 Public Welfare 2 2013-10-01 2012-10-01 true Does the receipt of Welfare-to-Work (WtW) cash... and Processing § 286.130 Does the receipt of Welfare-to-Work (WtW) cash assistance count towards a... as well as the penalty provision at § 286.195(a)(1), WtW cash assistance counts towards a...

  1. Magnetic and mechanical properties of Cu (75 wt%) - 316L grade stainless steels synthesized by ball milling and annealing

    NASA Astrophysics Data System (ADS)

    Mondal, Bholanath; Chabri, Sumit; Sardar, Gargi; Bhowmik, Nandagopal; Sinha, Arijit; Chattopadhyay, Partha Protim

    2015-05-01

    Elemental powders of Cu (75 wt%) and 316-stainless steel (25 wt%) has been subjected to ball milling upto 70 h followed by isothermal annealing at the temperature range of 350-750 °C for 1 h to investigate the microstructural evolution along with magnetic and mechanical properties. After 40 h of milling, the bcc Fe is almost dissolved in the solid solution of Cu but no significant change has been observed in the XRD pattern after 70 h of milling, Annealing of the alloy has resulted in precipitation of nanocrystalline bcc-Fe in Cu which triggers the soft ferromagnetic properties. The extensive mechanical characterization has been done at the microstructural scale by nanoindentation technique which demonstrates a hardening behavior of the compacted and annealed alloys due to possible precipitation of nanocrystalline bcc-Fe in Cu.

  2. Study on the corrosion residual strength of the 1.0 wt.% Ce modified AZ91 magnesium alloy

    SciTech Connect

    Li Chunfang; Liu Yaohui; Wang Qiang; Zhang Lina; Zhang Dawei

    2010-01-15

    The effect of corrosion on the tensile behaviour of the 1.0 wt.% Ce modified AZ91 magnesium alloy was investigated by the immersion of the test bar in 3.5 wt.% NaCl aqueous solution for 0, 12, 40, 108, 204, 372 and 468 h with the subsequent tensile tests in this paper. The fractography was analyzed by scanning electron microscopy. The results show that pitting corrosion should be responsible for the drop of the corrosion residual strength within the testing time. The depth of the corrosion pits was statistically and quantitatively obtained by an optical microscopy and the maximal value was recorded as the extreme depth of the corrosion pit. Furthermore, the corrosion residual strength is linearly dependent on the extreme depth of the corrosion pit, which can be attributed to the loss of cross-sectional area and the emergence of stress concentration caused by the initiation and development of corrosion pits.

  3. The effect of heat treatment on microstructures of melt-spun Fe 6.5 wt% Si alloys

    NASA Astrophysics Data System (ADS)

    Monstadt, H.; Hornbogen, E.; Rohde, J.

    1992-07-01

    The microstructures of melt-spun Fe 6.5 wt% Si alloys were investigated. In a special range of cooling rates, low silicon contents up to 9 wt% Si form a diffusion-controlled interface modulation (microsegregation). Amplitudes of the lamellar spacing increase with decreasing cooling rate. A model was developed to explain the transition from rapid crystallization of a homogeneous solid solution to microsegregation. A model for the homogenization of interdendritic segregation in the solid state was applied to the homogenization of the periodic microsegregations. The heat treatment parameters for the homogenization were verified by the experimental results. The relations of this structural phenomenon to bulk properties such as mechanical strength and ductility as well as magnetic properties are discussed briefly.

  4. /sup 238/PuO/sub 2//Mo-50 wt% Re compatibility at 800 and 1000/sup 0/C

    SciTech Connect

    Schaeffer, D.R.; Teaney, P.E.

    1980-07-18

    The compatibility of Mo-50 wt % Re with /sup 238/PuO/sub 2/ was investigated after heat treatments of up to 720 days at 800/sup 0/C and 180 days at 1000/sup 0/C. At 800/sup 0/C, a 1-..mu..m thick, continuous layer of molybdenum oxide resulted. At 1000/sup 0/C, the oxide reaction product contained some plutonium and did not appear continuous. At 1000/sup 0/C, a layer of intermetallic formed at the Mo-Re edge, beneath the oxide layer, creating a barrier between the Mo-50 wt % Re and the /sup 238/PuO/sub 2/. The intermetallic layer was promoted by the iron impurity in the /sup 238/PuO/sub 2/.

  5. Dynamic Compression Properties of an Ultrafine-Grained Al-26 wt.% Si Alloy Fabricated by Equal-Channel Angular Pressing

    NASA Astrophysics Data System (ADS)

    Jiang, Jinghua; Shi, Jun; Yao, YiHong; Ma, Aibin; Song, Dan; Yang, Donghui; Chen, Jianqing; Lu, Fumin

    2015-05-01

    The grains of a hypereutectic Al-26 wt.% Si alloy were drastically refined by multi-pass equal-channel angular pressing (ECAP). Compression deformation characteristics of the alloy with different microstructure were examined at two dynamic strain rates (700, 1000 s-1) by a split-Hopkinson pressure bar system and at a quasi-static strain rate (0.001 s-1) by a universal testing machine, respectively. The results reveal that the Al-26 wt.% Si alloy is strain-rate sensitive under those compression conditions, i.e., the initial yield stress and the flow stress considerably increase with the strain rate. Grain refinement through ECAP improves the strain-rate sensitivity of the alloy. With rising the ECAP temperature, the yield stress of the ultrafine-grained alloy decreases but the strain value increases during dynamic compression.

  6. Physical characterization of the potentially hazardous high-albedo Asteroid (33342) 1998 WT 24 from thermal-infrared observations

    NASA Astrophysics Data System (ADS)

    Harris, Alan W.; Mueller, Michael; Delbó, Marco; Bus, Schelte J.

    2007-06-01

    The potentially hazardous Asteroid (33342) 1998 WT 24 approached the Earth within 0.0125 AU on 2001 December 16 and was the target of a number of optical, infrared, and radar observing campaigns. Interest in 1998 WT 24 stems from its having an orbit with an unusually low perihelion distance, which causes it to cross the orbits of the Earth, Venus, and Mercury, and its possibly being a member of the E spectral class, which is rare amongst near-Earth asteroids (NEAs). We present the results of extensive thermal-infrared observations of 1998 WT 24 obtained in December 2001 with the 3-m NASA Infrared Telescope Facility (IRTF) on Mauna Kea, Hawaii and the ESO 3.6-m telescope in Chile. A number of thermal models have been applied to the data, including thermophysical models that give best-fit values of 0.35±0.04 km for the effective diameter, 0.56±0.2 for the geometric albedo, p, and 100-300 J m -2 s -0.5 K -1 for the thermal inertia. Our values for the diameter and albedo are consistent with results derived from radar and polarimetric observations. The albedo is one of the highest values obtained for any asteroid and, since no other taxonomic type is associated with albedos above 0.5, supports the suggested rare E-type classification for 1998 WT 24. The thermal inertia is an order of magnitude higher than values derived for large main-belt asteroids but consistent with the relatively high values found for other near-Earth asteroids. A crude pole solution inferred from a combination of our observations and published radar results is β=-52°, λ=355° (J2000), but we caution that this is uncertain by several tens of degrees.

  7. Chemical analyses of pore water from boreholes USW SD-6 and USW WT-24, Yucca Mountain, Nevada.

    PubMed

    Yang, In C; Peterman, Zell E; Scofield, Kevin M

    2003-01-01

    Analyses of pore water extracted from cores of boreholes USW SD-6 in the central part and USW WT-24 in the northern part of Yucca Mountain, Nevada, show significant vertical and lateral variations in dissolved-ion concentrations. Analyses of samples of only a few milliliters of pore water extracted by uniaxial or triaxial compression and by ultracentrifugation methods from adjacent core samples are generally in agreement, within the analytical error of 10% to 15%. However, the values of silica for water obtained by ultracentrifugation are consistently lower than values for water obtained by compression. The larger concentrations probably are due to localized pressure solution of silicate minerals during compression. The shallower water from core in borehole USW SD-6 was extracted from nonwelded units collectively referred to as the Paintbrush Tuff nonwelded (PTn). The deeper water was from core in both boreholes USW SD-6 and USW WT-24 in the nonwelded units referred to as the Calico Hills nonwelded (CHn). Significant differences in mean dissolved-ion concentrations in pore water between the PTn and CHn are (1) decreases in Ca, Mg, SO(4), and NO(3) and (2) increases in HCO(3) and (Na+K)/(Ca+Mg) ratios. The decrease in NO(3) and the increase in HCO(3) could be the result of denitrification through the oxidation of organic matter. The decrease in Ca and associated increase in (Na+K)/(Ca+Mg) is the result of ion exchange with zeolites in the CHn in borehole USW WT-24. This effect is not nearly as pronounced in borehole USW SD-6, probably reflecting a smaller amount of zeolitization of the CHn in USW SD-6. Geochemical calculations using the PHREEQC code indicate that the pore water from both boreholes USW SD-6 and USW WT-24 is uniformly undersaturated in anhydrite, gypsum, and amorphous silica, but supersaturated in quartz and chalcedony. The saturation of calcite, aragonite, sepiolite, and dolomite is more variable from sample to sample. PMID:12714300

  8. Mechanical Properties of Plasma-Sprayed ZrO2-8 wt% Y2O3 Thermal Barrier Coatings

    NASA Technical Reports Server (NTRS)

    Choi, Sung R.; Zhu, Dongming; Miller, Robert A.

    2004-01-01

    Mechanical behavior of free standing, plasma-sprayed ZrO2-8 wt% Y2O3 thermal barrier coatings, including strength, fracture toughness, fatigue, constitutive relation, elastic modulus, and directionality, has been determined under various loading-specimen configurations. This report presents and describes a summary of mechanical properties of the plasma-sprayed coating material to provide them as a design database.

  9. A heterozygous IDH1R132H/WT mutation induces genome-wide alterations in DNA methylation

    PubMed Central

    Duncan, Christopher G.; Barwick, Benjamin G.; Jin, Genglin; Rago, Carlo; Kapoor-Vazirani, Priya; Powell, Doris R.; Chi, Jen-Tsan; Bigner, Darell D.; Vertino, Paula M.; Yan, Hai

    2012-01-01

    Monoallelic point mutations of the NADP+-dependent isocitrate dehydrogenases IDH1 and IDH2 occur frequently in gliomas, acute myeloid leukemias, and chondromas, and display robust association with specific DNA hypermethylation signatures. Here we show that heterozygous expression of the IDH1R132H allele is sufficient to induce the genome-wide alterations in DNA methylation characteristic of these tumors. Using a gene-targeting approach, we knocked-in a single copy of the most frequently observed IDH1 mutation, R132H, into a human cancer cell line and profiled changes in DNA methylation at over 27,000 CpG dinucleotides relative to wild-type parental cells. We find that IDH1R132H/WT mutation induces widespread alterations in DNA methylation, including hypermethylation of 2010 and hypomethylation of 842 CpG loci. We demonstrate that many of these alterations are consistent with those observed in IDH1-mutant and G-CIMP+ primary gliomas and can segregate IDH wild-type and mutated tumors as well as those exhibiting the G-CIMP phenotype in unsupervised analysis of two primary glioma cohorts. Further, we show that the direction of IDH1R132H/WT-mediated DNA methylation change is largely dependent upon preexisting DNA methylation levels, resulting in depletion of moderately methylated loci. Additionally, whereas the levels of multiple histone H3 and H4 methylation modifications were globally increased, consistent with broad inhibition of histone demethylation, hypermethylation at H3K9 in particular accompanied locus-specific DNA hypermethylation at several genes down-regulated in IDH1R132H/WT knock-in cells. These data provide insight on epigenetic alterations induced by IDH1 mutations and support a causal role for IDH1R132H/WT mutants in driving epigenetic instability in human cancer cells. PMID:22899282

  10. In vitro phosphorylation does not influence the aggregation kinetics of WT α-synuclein in contrast to its phosphorylation mutants.

    PubMed

    Schreurs, Sarah; Gerard, Melanie; Derua, Rita; Waelkens, Etienne; Taymans, Jean-Marc; Baekelandt, Veerle; Engelborghs, Yves

    2014-01-01

    The aggregation of alpha-synuclein (α-SYN) into fibrils is characteristic for several neurodegenerative diseases, including Parkinson's disease (PD). Ninety percent of α-SYN deposited in Lewy Bodies, a pathological hallmark of PD, is phosphorylated on serine129. α-SYN can also be phosphorylated on tyrosine125, which is believed to regulate the membrane binding capacity and thus possibly its normal function. A better understanding of the effect of phosphorylation on the aggregation of α-SYN might shed light on its role in the pathogenesis of PD. In this study we compare the aggregation properties of WT α-SYN with the phospho-dead and phospho-mimic mutants S129A, S129D, Y125F and Y125E and in vitro phosphorylated α-SYN using turbidity, thioflavin T and circular dichroism measurements as well as transmission electron microscopy. We show that the mutants S129A and S129D behave similarly compared to wild type (WT) α-SYN, while the mutants Y125F and Y125E fibrillate significantly slower, although all mutants form fibrillar structures similar to the WT protein. In contrast, in vitro phosphorylation of α-SYN on either S129 or Y125 does not significantly affect the fibrillization kinetics. Moreover, FK506 binding proteins (FKBPs), enzymes with peptidyl-prolyl cis-trans isomerase activity, still accelerate the aggregation of phosphorylated α-SYN in vitro, as was shown previously for WT α-SYN. In conclusion, our results illustrate that phosphorylation mutants can display different aggregation properties compared to the more biologically relevant phosphorylated form of α-SYN. PMID:24434619

  11. Early postnatal myelin content estimate of white matter via T1w/T2w ratio

    NASA Astrophysics Data System (ADS)

    Lee, Kevin; Cherel, Marie; Budin, Francois; Gilmore, John; Zaldarriaga Consing, Kirsten; Rasmussen, Jerod; Wadhwa, Pathik D.; Entringer, Sonja; Glasser, Matthew F.; Van Essen, David C.; Buss, Claudia; Styner, Martin

    2015-03-01

    To develop and evaluate a novel processing framework for the relative quantification of myelin content in cerebral white matter (WM) regions from brain MRI data via a computed ratio of T1 to T2 weighted intensity values. We employed high resolution (1mm3 isotropic) T1 and T2 weighted MRI from 46 (28 male, 18 female) neonate subjects (typically developing controls) scanned on a Siemens Tim Trio 3T at UC Irvine. We developed a novel, yet relatively straightforward image processing framework for WM myelin content estimation based on earlier work by Glasser, et al. We first co-register the structural MRI data to correct for motion. Then, background areas are masked out via a joint T1w and T2 foreground mask computed. Raw T1w/T2w-ratios images are computed next. For purpose of calibration across subjects, we first coarsely segment the fat-rich facial regions via an atlas co-registration. Linear intensity rescaling based on median T1w/T2w-ratio values in those facial regions yields calibrated T1w/T2wratio images. Mean values in lobar regions are evaluated using standard statistical analysis to investigate their interaction with age at scan. Several lobes have strongly positive significant interactions of age at scan with the computed T1w/T2w-ratio. Most regions do not show sex effects. A few regions show no measurable effects of change in myelin content change within the first few weeks of postnatal development, such as cingulate and CC areas, which we attribute to sample size and measurement variability. We developed and evaluated a novel way to estimate white matter myelin content for use in studies of brain white matter development.

  12. Electrochemical behavior and effect of heat treatment on morphology, crystalline structure of self-organized TiO2 nanotube arrays on Ti-6Al-7Nb for biomedical applications.

    PubMed

    Mohan, L; Anandan, C; Rajendran, N

    2015-05-01

    In the present work, we investigate the formation of self-organized titanium oxide nanotube layers by anodic oxidation on titanium alloy Ti-6Al-7Nb in electrolyte solution containing sulfuric acid and hydrofluoric acid. The anodized surface was characterized by micro-Raman, X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and energy-dispersive X-ray spectroscopy (EDS). The corrosion behavior of the treated and untreated samples was investigated through electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization studies in simulated body fluid (Hanks' solution). The investigations show that the native oxide on the sample is replaced by self-assembled nanoarray by anodization. FESEM of samples annealed at 450 to 800 °C show tubular morphology whereas those annealed at 850 °C show collapse of nanotubes. Electrochemical impedance data of the substrate and 10 V anodized samples were fitted with a two-time constant equivalent circuit and that of anodized samples (20, 30 V) with a three-time constant equivalent circuit. PMID:25746285

  13. Wilms’ Tumor Gene 1 (WT1) Silencing Inhibits Proliferation of Malignant Peripheral Nerve Sheath Tumor sNF96.2 Cell Line

    PubMed Central

    Parenti, Rosalba; Cardile, Venera; Graziano, Adriana Carol Eleonora; Parenti, Carmela; Venuti, Assunta; Bertuccio, Maria Paola; Furno, Debora Lo; Magro, Gaetano

    2014-01-01

    Wilms’ tumor gene 1 (WT1) plays complex roles in tumorigenesis, acting as tumor suppressor gene or an oncogene depending on the cellular context. WT1 expression has been variably reported in both benign and malignant peripheral nerve sheath tumors (MPNSTs) by means of immunohistochemistry. The aim of the present study was to characterize its potential pathogenetic role in these relatively uncommon malignant tumors. Firstly, immunohistochemical analyses in MPNST sNF96.2 cell line showed strong WT1 staining in nuclear and perinuclear areas of neoplastic cells. Thus, we investigated the effects of silencing WT1 by RNA interference. Through Western Blot analysis and proliferation assay we found that WT1 knockdown leads to the reduction of cell growth in a time- and dose-dependent manner. siWT1 inhibited proliferation of sNF96.2 cell lines likely by influencing cell cycle progression through a decrease in the protein levels of cyclin D1 and inhibition of Akt phosphorylation compared to the control cells. These results indicate that WT1 knockdown attenuates the biological behavior of MPNST cells by decreasing Akt activity, demonstrating that WT1 is involved in the development and progression of MPNSTs. Thus, WT1 is suggested to serve as a potential therapeutic target for MPNSTs. PMID:25474318

  14. Extended FDD-WT method based on correcting the errors due to non-synchronous sensing of sensors

    NASA Astrophysics Data System (ADS)

    Tarinejad, Reza; Damadipour, Majid

    2016-05-01

    In this research, a combinational non-parametric method called frequency domain decomposition-wavelet transform (FDD-WT) that was recently presented by the authors, is extended for correction of the errors resulting from asynchronous sensing of sensors, in order to extend the application of the algorithm for different kinds of structures, especially for huge structures. Therefore, the analysis process is based on time-frequency domain decomposition and is performed with emphasis on correcting time delays between sensors. Time delay estimation (TDE) methods are investigated for their efficiency and accuracy for noisy environmental records and the Phase Transform - β (PHAT-β) technique was selected as an appropriate method to modify the operation of traditional FDD-WT in order to achieve the exact results. In this paper, a theoretical example (3DOF system) has been provided in order to indicate the non-synchronous sensing effects of the sensors on the modal parameters; moreover, the Pacoima dam subjected to 13 Jan 2001 earthquake excitation was selected as a case study. The modal parameters of the dam obtained from the extended FDD-WT method were compared with the output of the classical signal processing method, which is referred to as 4-Spectral method, as well as other literatures relating to the dynamic characteristics of Pacoima dam. The results comparison indicates that values are correct and reliable.

  15. Transmission electron microscopy characterization of the fission gas bubble superlattice in irradiated U-7wt% Mo dispersion fuels

    SciTech Connect

    B.D. Miller; J. Gan; D.D. Keiser Jr.; A.B. Robinson; J.-F. Jue; J.W. Madden; P.G. Medvedev

    2015-03-01

    Transmission electron microscopy characterization of irradiated U-7wt% Mo dispersion fuel was performed on various samples to understand the effect of irradiation parameters (fission density, fission rate, and temperature) on the self-organized fission-gas-bubble superlattice that forms in the irradiated U-Mo fuel. The bubble superlattice was seen to form a face-centered cubic structure coherent with the host U-7wt% Mo body centered cubic structure. At a fission density between 3.0 and 4.5 x 1021 fiss/cm3, the superlattice bubbles appear to have reached a saturation size with additional fission gas associated with increasing burnup predominately accumulating along grain boundaries. At a fission density of ~4.5x1021 fiss/cm3, the U-7wt% Mo microstructure undergoes grain subdivision and can no longer support the ordered bubble superlattice. The fuel grains are primarily less than 500 nm in diameter with micron-size fission-gas bubbles present on the grain boundaries. Solid fission products decorate the inside surface of the micron-sized fission-gas bubbles. Residual superlattice bubbles are seen in areas where fuel grains remain micron sized. Potential mechanisms of the formation and collapse of the bubble superlattice are discussed.

  16. Early-stage nucleation of manganese sulfide particle and its processing evolution in Fe—3wt.%Si alloys

    NASA Astrophysics Data System (ADS)

    Guo, Wei; Meng, Li; Wang, Hongcai; Yan, Guochun; Mao, Weimin

    2016-03-01

    Manganese sulfide is often referred to as one of important inhibitors in grain-oriented electrical steels, which is of great importance to yield strong Goss texture. However, the early stage of nucleation for such inhibitors and their evolution during the processing has not been well understood. In present work we selected a Fe—3.12wt.%Si—0.11wt.%Mn—0.021wt.%S model system and used FE-SEM and atom probe tomography (APT) to investigate the precipitation behavior of MnS inhibitors at near atomic scale. It was found that the Si—S enriched clusters with sizes of 5—15 nm were formed close to the MnS particles. The density of inhibitors decreased after large pseudo-plane-strain compression because of the effect of dislocation motion, and then slightly increased again when sample was aged at 200°C for 48 h. The dislocations and grain boundaries can act as fast diffusion paths and assist the reemergence of Si—S enriched clusters.

  17. Antileukemia multifunctionality of CD4(+) T cells genetically engineered by HLA class I-restricted and WT1-specific T-cell receptor gene transfer.

    PubMed

    Fujiwara, H; Ochi, T; Ochi, F; Miyazaki, Y; Asai, H; Narita, M; Okamoto, S; Mineno, J; Kuzushima, K; Shiku, H; Yasukawa, M

    2015-12-01

    To develop gene-modified T-cell-based antileukemia adoptive immunotherapy, concomitant administration of CD4(+) and CD8(+) T cells that have been gene modified using identical HLA class I-restricted leukemia antigen-specific T-cell receptor (TCR) gene transfer has not yet been fully investigated. Here, using CD4(+) and CD8(+) T cells that had been gene modified with a retroviral vector expressing HLA-A*24:02-restricted and Wilms' tumor 1 (WT1)-specific TCR-α/β genes and siRNAs for endogenous TCRs (WT1-siTCR/CD4(+) T cells and WT1-siTCR/CD8(+) T cells), we examined the utility of this strategy. WT1-siTCR/CD4(+) T cells sufficiently recognized leukemia cells in an HLA class I-restricted manner and provided target-specific Th1 help for WT1-siTCR/CD8(+) T cells. By using a xenografted mouse model, we found that WT1-siTCR/CD4(+) T cells migrated to leukemia sites and subsequently attracted WT1-siTCR/CD8(+) T cells via chemotaxis. Therapy-oriented experiments revealed effective enhancement of leukemia suppression mediated by concomitant administration of WT1-siTCR/CD4(+) T cells and WT1-siTCR/CD8(+) T cells. Importantly, this augmented efficacy in the presence of WT1-siTCR/CD4(+) T cells was correlated with longer survival and enhanced formation of memory T cells by WT1-siTCR/CD8(+) T cells. Collectively, our experimental findings strongly suggest that this strategy would be clinically advantageous for the treatment of human leukemia. PMID:26104661

  18. Microstructural and Tribological Properties of Al2O3-13pctTiO2 Thermal Spray Coatings Deposited by Flame Spraying

    NASA Astrophysics Data System (ADS)

    Younes, Rassim; Bradai, Mohand Amokrane; Sadeddine, Abdelhamid; Mouadji, Youcef; Bilek, Ali; Benabbas, Abderrahim

    2015-10-01

    T He present investigation has been conducted to study the tribological properties of Al2O3-13pctTiO2 (AT-13) ceramic coatings deposited on a low carbon steel type E335 by using a thermal flame spray technique. The microstructure and phase composition of wire and coatings were analyzed by scanning electron microscope, energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD). Measurements of micro hardness were also performed on the surface of the coatings. The tribological tests were carried out using a pin-on-disk tribometer at different loads. All tests were performed using two disks as counter body, namely Al2O3-ZrO2 (AZ-25) and Al2O3-TiO2 (AT-3) which formed couple 1 and couple 2, respectively, in order to work out the wear rate and friction coefficient. Roughness profiles were also evaluated before and after each test. The SEM showed that the dense microstructure of Al2O3-TiO2 (AT-13) coatings have a homogenous lamellar morphology and complex of several phases with the presence of porosities and unmelted particles. The XRD analysis of the wire before the spray showed a majority phase of α-Al2O3 rhombohedral structure and a secondary phase of Al2TiO5 orthorhombic structure with little traces of TiO2 (rutile) tetragonal structure, whereas the XRD of the coating revealed the disappearance of TiO2 replaced by the formation of a new metastable phase γ-Al2O3 cubic structure. The tribological results showed that the applied contact pressure affects the variation of the friction coefficient with time and that it decreases with the rise of the normal force of contact. It was found also that the couple 2 with nearly chemical compositions of spray-coated (AT-13) and disk (AT-3) exhibited much higher wear resistance than the couple 1 although they have sliding coefficient of friction nearly.

  19. Inhibition of cellular proliferation by the Wilms' tumor suppressor WT1 is associated with suppression of insulin-like growth factor I receptor gene expression.

    PubMed Central

    Werner, H; Shen-Orr, Z; Rauscher, F J; Morris, J F; Roberts, C T; LeRoith, D

    1995-01-01

    We have investigated the regulation of the insulin-like growth factor I receptor (IGF-I-R) gene promoter by the Wilms' tumor suppressor WT1 in intact cells. The levels of endogenous IGF-I-R mRNA and the activity of IGF-I-R gene promoter fragments in luciferase reporter constructs were found to be significantly higher in G401 cells (a Wilms' tumor-derived cell line lacking detectable WT1 mRNA) than in 293 cells (a human embryonic kidney cell line which expresses significant levels of WT1 mRNA). To study whether WT1 could suppress the expression of the endogenous IGF-I-R gene, WT1-negative G401 cells were stably transfected with a WT1 expression vector. Expression of WT1 mRNA in G401 cells resulted in a significant decrease in the rate of cellular proliferation, which was associated with a reduction in the levels of IGF-I-R mRNA, promoter activity, and ligand binding and with a reduction in IGF-I-stimulated cellular proliferation, thymidine incorporation, and anchorage-independent growth. These data suggest that a major aspect of the action of the WT1 tumor suppressor is the repression of IGF-I-R gene expression. PMID:7791758

  20. Specificity for the tumor-associated self-antigen WT1 drives the development of fully functional memory T cells in the absence of vaccination.

    PubMed

    Pospori, Constandina; Xue, Shao-An; Holler, Angelika; Voisine, Cecile; Perro, Mario; King, Judith; Fallah-Arani, Farnaz; Flutter, Barry; Chakraverty, Ronjon; Stauss, Hans J; Morris, Emma C

    2011-06-23

    Recently, vaccines against the Wilms Tumor antigen 1 (WT1) have been tested in cancer patients. However, it is currently not known whether physiologic levels of WT1 expression in stem and progenitor cells of normal tissue result in the deletion or tolerance induction of WT1-specific T cells. Here, we used an human leukocyte antigen-transgenic murine model to study the fate of human leukocyte antigen class-I restricted, WT1-specific T cells in the thymus and in the periphery. Thymocytes expressing a WT1-specific T-cell receptor derived from high avidity human CD8 T cells were positively selected into the single-positive CD8 population. In the periphery, T cells specific for the WT1 antigen differentiated into CD44-high memory phenotype cells, whereas T cells specific for a non-self-viral antigen retained a CD44(low) naive phenotype. Only the WT1-specific T cells, but not the virus-specific T cells, displayed rapid antigen-specific effector function without prior vaccination. Despite long-term persistence of WT1-specific memory T cells, the animals did not develop autoimmunity, and the function of hematopoietic stem and progenitor cells was unimpaired. This is the first demonstration that specificity for a tumor-associated self-antigen may drive differentiation of functionally competent memory T cells. PMID:21447831

  1. 20 CFR 645.125 - What are the roles of the local and State governmental partners in the governance of the WtW...

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 20 Employees' Benefits 3 2011-04-01 2011-04-01 false What are the roles of the local and State governmental partners in the governance of the WtW program? 645.125 Section 645.125 Employees' Benefits... governance of the WtW program? (a) Local boards or alternate administering agencies, in coordination with...

  2. 20 CFR 645.125 - What are the roles of the local and State governmental partners in the governance of the WtW...

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 20 Employees' Benefits 3 2013-04-01 2013-04-01 false What are the roles of the local and State governmental partners in the governance of the WtW program? 645.125 Section 645.125 Employees' Benefits... governance of the WtW program? (a) Local boards or alternate administering agencies, in coordination with...

  3. 20 CFR 645.125 - What are the roles of the local and State governmental partners in the governance of the WtW...

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 20 Employees' Benefits 3 2012-04-01 2012-04-01 false What are the roles of the local and State governmental partners in the governance of the WtW program? 645.125 Section 645.125 Employees' Benefits... governance of the WtW program? (a) Local boards or alternate administering agencies, in coordination with...

  4. 20 CFR 645.125 - What are the roles of the local and State governmental partners in the governance of the WtW...

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 20 Employees' Benefits 3 2014-04-01 2014-04-01 false What are the roles of the local and State governmental partners in the governance of the WtW program? 645.125 Section 645.125 Employees' Benefits... governance of the WtW program? (a) Local boards or alternate administering agencies, in coordination with...

  5. The effect of interstitial carbon on the mechanical properties and dislocation substructure evolution in Fe40.4Ni11.3Mn34.8Al7.5Cr6 high entropy alloys

    DOE PAGESBeta

    Wang, Zhangwei; Baker, Ian; Cai, Zhonghou; Chen, Si; Poplawsky, Jonathan D.; Guo, Wei

    2016-09-01

    A systematic study of the effects of up to 1.1 at. % carbon on the mechanical properties and evolution of the dislocation substructure in a series of a high entropy alloys (HEA) based on Fe40.4Ni11.3Mn34.8Al7.5Cr6 is presented. Transmission electron microscopy (TEM), synchrotron X-ray diffraction (XRD) and atom probe tomography (APT) were used to show that all the alloys are single-phase f.c.c. random solid solutions. The lattice constant, determined from synchrotron XRD measurements, increases linearly with increasing carbon concentration, which leads to a linear relationship between the yield strength and the carbon concentration. The dislocation substructures, as determined by a TEM,more » show a transition from wavy slip to planar slip and, at higher strains, and from cell-forming structure (dislocations cells, cell blocks and dense dislocation walls) to non-cell forming structure (Taylor lattice, microbands and domain boundaries) with the addition of carbon, features related to the increase in lattice friction stress. The stacking fault energy (measured via weak-beam imaging of the separation of dislocation partials) decreases with increasing carbon content, which also contributes to the transition from wavy slip to planar slip. The formation of non-cell forming structure induced by carbon leads to a high degree of strain hardening and a substantial increase in the ultimate tensile strength. In conclusion, the consequent postponement of necking due to the high strain hardening, along with the plasticity accommodation arising from the formation of microbands and domain boundaries, result in an increase of ductility due to the carbon addition.« less

  6. Micro-CT and histological analysis of Ti6Al7Nb custom made implants with hydroxyapatite and SiO2-TiO2 coatings in a rabbit model

    PubMed Central

    ARMENCEA, GABRIEL; BERCE, CRISTIAN; ROTARU, HORATIU; BRAN, SIMION; LEORDEAN, DAN; COADA, CAMELIA; TODEA, MILICA; JULA, CAMELIA AUGUSTA; GHEBAN, DAN; BACIUT, GRIGORE; BACIUT, MIHAELA; CAMPIAN, RADU SEPTIMIU

    2015-01-01

    Background and aim Bone defect reconstruction in the maxillofacial area comes as a necessity after traumatic, oncological or congenital pathology. Custom made implant manufacturing, such as selective laser melting (SLM), is very helpful when bone reconstruction is needed. In the present study we assessed the osseointegration of custom made implants made of Ti6Al7Nb with two different coatings: SiO2-TiO2 and hydroxyapatite, by comparing the bone mineral density (BMD) measured on micro-CT and the histological mineralized bone surrounding the implants. Methods Custom made – cylindrical type – implants were produced by selective laser melting, coated with SiO2-TiO2 and hydroxyapatite and implanted in the rabbit femur. The animals (divided into 3 groups) were sacrificed at 1, 3 and 6 months and the implants were removed together with the surrounding bone. Bone mineral density and histological examination of the bone-implant surface was performed for each group. Results BMD and histological examination of the samples determined the quantity of mineralized bone at the implant site, showing a good percentage of mineralized bone for the coated implants at 1, 3 and 6 months. The measurements for the implants without coating showed a significant lower quantity of mineralized bone at 3 months compared with the implants with coating, and a good quantity of mineralized bone at 6 months, showing a process of demineralization followed by remineralization in the last month. The measurements of BMD showed similar results with the histological examination. Conclusions The use of micro-CT and the measurement of BMD are a reliable, minimally invasive and a quick method of osseointegration assessment. PMID:26609278

  7. Therapeutic Efficacy of an Fc-Enhanced TCR-Like Antibody to the Intracellular WT1 Oncoprotein

    PubMed Central

    Veomett, Nicholas; Dao, Tao; Liu, Hong; Xiang, Jingyi; Pankov, Dmitry; Dubrovsky, Leonid; Whitten, Joseph A.; Park, Sun-Mi; Korontsvit, Tatyana; Zakhaleva, Victoria; Casey, Emily; Curcio, Michael; Kharas, Michael G.; O’Reilly, Richard J.; Liu, Cheng; Scheinberg, David A.

    2014-01-01

    Purpose RMFPNAPYL (RMF), a WT1-derived CD8 T cell epitope presented by HLA-A*02:01, is a validated target for T-cell-based immunotherapy. We previously reported ESK1, a high avidity (Kd < 0.2nM), fully-human monoclonal antibody (mAb) specific for the WT1 RMF peptide/HLA-A*02:01 complex, which selectively bound and killed WT1+ and HLA-A*02:01+ leukemia and solid tumor cell lines. Experimental Design We engineered a second-generation mAb, ESKM, to have enhanced antibody dependent cell-mediated cytotoxicity (ADCC) function due to altered Fc glycosylation. ESKM was compared to native ESK1 in binding assays, in vitro ADCC assays, and mesothelioma and leukemia therapeutic models and pharmacokinetic studies in mice. ESKM toxicity was assessed in HLA-A*02:01+ transgenic mice. Results ESK antibodies mediated ADCC against hematopoietic and solid tumor cells at concentrations below 1µg/ml, but ESKM was about 5–10 fold more potent in vitro against multiple cancer cell lines. ESKM was more potent in vivo against JMN mesothelioma, and effective against SET2 AML and fresh ALL xenografts. ESKM had a shortened half-life (4.9 vs 6.5 days), but an identical biodistribution pattern in C57BL6/J mice. At therapeutic doses of ESKM, there was no difference in half-life or biodistribution in HLA-A*02:01+ transgenic mice compared to the parent strain. Importantly, therapeutic doses of ESKM in these mice caused no depletion of total WBCs or hematopoetic stem cells, or pathologic tissue damage. Conclusions The data provide proof of concept that an Fc-enhanced mAb can improve efficacy against a low-density, tumor-specific, peptide/MHC target, and support further development of this mAb against an important intracellular oncogenic protein. PMID:24850840

  8. Quantitative comparison of airborne remote-sensed and in situ Rhodamine WT dye and temperature during RIVET & IB09

    NASA Astrophysics Data System (ADS)

    Lenain, L.; Clark, D. B.; Guza, R. T.; Hally-Rosendahl, K.; Statom, N.; Feddersen, F.

    2012-12-01

    The transport and evolution of temperature, sediment, chlorophyll, fluorescent dye, and other tracers is of significant oceanographic interest, particularly in complex coastal environments such as the nearshore, river mouths, and tidal inlets. Remote sensing improves spatial coverage over in situ observations, and ground truthing remote sensed observations is critical for its use. Here, we present remotely sensed observations of Rhodamine WT dye and Sea Surface Temperature (SST) using the SIO Modular Aerial Sensing System (MASS) and compare them with in situ observations from the IB09 (0-300 m seaward of the surfzone, Imperial Beach, CA, October 2009) and RIVET (New River Inlet, NC, May 2012) field experiments. Dye concentrations are estimated from a unique multispectral camera system that measures the emission and absorption wavelengths of Rhodamine WT dye. During RIVET, dye is also characterized using a pushbroom hyperspectral imaging system (SPECIM AISAEagle VNIR 400-990 nm) while SST is estimated using a long-wave infrared camera (FLIR SC6000HS) coupled with an infrared pyrometer (Heitronics KT19.85II). Repeated flight passes over the dye plume were conducted approximately every 5 min for up to 4.5 hr in duration with a swath width ranging from 400 to 2000 m (altitude dependent), and provided a unique spatio-temporal depiction of the plume. A dye proxy is developed using the measured radiance at the emission and absorption wavelengths of the Rhodamine WT dye. During IB09 and RIVET, in situ dye and temperature were measured with two GPS-tracked jet skis, a small boat, and moored observations. The in situ observations are compared with the remotely sensed data in these two complex coastal environments. Funding was provided by the Office of Naval Research.

  9. WT1 PEPTIDE VACCINATIONS INDUCE CD4 AND CD8 T CELL IMMUNE RESPONSES IN PATIENTS WITH MESOTHELIOMA AND NON-SMALL CELL LUNG CANCER

    PubMed Central

    Krug, Lee M.; Dao, Tao; Brown, Andrew B.; Maslak, Peter; Travis, William; Bekele, Sara; Korontsvit, Tatyana; Zakhaleva, Victoria; Wolchok, Jedd; Yuan, Jianda; Li, Hao; Tyson, Leslie; Scheinberg, David A.

    2014-01-01

    BACKGROUND The transcription factor, WT1, is highly overexpressed in malignant pleural mesothelioma (MPM) and immunohistochemical stains for WT1 are used routinely to aid in its diagnosis. Using computer prediction analysis we designed analog peptides derived from WT1 sequences by substituting amino acids at key HLA-A0201 binding positions. We tested the safety and immunogenicity of a WT1 vaccine comprised of four class 1 and class 2 peptides in patients with thoracic neoplasms expressing WT1. METHODS Therapy consisted of six subcutaneous vaccinations administered with Montanide adjuvant on weeks 0, 4, 6, 8, 10, and 12, with 6 additional monthly injections for responding patients. Injection sites were pre-stimulated with GM-CSF (70mcg). Immune responses were evaluated by DTH, CD4 T-cell proliferation, CD8 T-cell interferon gamma release, intracellular cytokine staining, WT1 peptide MHC-tetramer staining, and cytotoxicity against WT1 positive tumor cells. RESULTS Nine patients with MPM and 3 with NSCLC were vaccinated, with 8 patients receiving at least 6 vaccinations; in total, 10 patients were evaluable for immune response. Six out of nine patients tested demonstrated CD4 T-cell proliferation to WT1 specific peptides, and five of the six HLA-A0201 patients tested mounted a CD8 T-cell response. Stimulated T cells were capable of cytotoxicity against WT-1 positive cells. Vaccination also induced polyfunctional CD8 T cell responses. CONCLUSIONS This multivalent WT1 peptide analog vaccine induces immune responses in a high proportion of patients with thoracic malignancies with minimal toxicity. A randomized trial testing this vaccine as adjuvant therapy in MPM is planned. PMID:20532500

  10. Investigating the effect of multiple grain-grain interfaces on electric and magnetic properties of [50 wt% BaFe12O19-50 wt% Na0.5Bi0.5TiO3] composite system

    NASA Astrophysics Data System (ADS)

    Pattanayak, Ranjit; Muduli, Rakesh; Panda, Ranjit Kumar; Dash, Tapan; Sahu, Priyanka; Raut, Subhajit; Panigrahi, Simanchala

    2016-03-01

    This report presents the fabrication, electrical properties along with the magnetic parameters of a composite system considering a strong ferrimagnetic (BaFe12O19) and a ferroelectric (Na0.5Bi0.5TiO3) material. Polycrystalline 50 wt% BaFe12O19 (BaM)-50 wt% Na0.5Bi0.5TiO3 (NBT) composite system was prepared by the solid state reaction method. Rietveld refinement of XRD pattern confirms the presence of BaM and NBT phases without any impurity phase. From scanning electron micrograph both the phases are also clearly identified. In this report, the electric relaxation and conductivity properties were systematically investigated and analyzed in the frequency range of 100 Hz to 1 MHz and temperature range of 30-200 °C. The presence of different type of grains and significant reduction in the resistance of the composite system were found to be responsible for the nature of electric relaxation behavior. A peculiar and interesting evolution of grain boundary conduction was detected which was argued due to the existence of three possible grain boundaries such as: (i) BaM-BaM interface, (ii) NBT-NBT interface and (iii) BaM-NBT interface. The magnetization study (M-H loop) paves that, the saturation magnetization and coercive field reduces for composite system.

  11. Magnetic and mechanical properties of rapidly solidified FeSi 6.5 wt% alloys and their interpretation

    NASA Astrophysics Data System (ADS)

    Viala, B.; Degauque, J.; Baricco, M.; Ferrara, E.; Pasquale, M.; Fiorillo, F.

    1996-07-01

    The structural, mechanical and magnetic properties of FeSi 6.5 wt% rapidly solidified alloys have been investigated following recrystallization annealing and different rates of cooling through the B 2 + DO 3 ordering region (1 ≤ T ≤ 1500° C min -1). A transition from ductile to brittle behavior is observed for T < ˜ 1000°C min -1, chiefly due to B 2 ordering and the associated formation of superlattice dislocations, having reduced glide and cross-slip capability. The magnetic behavior appears, however, to be weakly dependent on T, with the energy losses minimized for average grain size around 100-150 μm.

  12. Synchrotron X-ray Tomographic Quantification of Deformation Induced Strain Localisation in Semi-solid Al- 15wt.%Cu

    NASA Astrophysics Data System (ADS)

    Cai, B.; Karagadde, S.; Marrow, T. J.; Connolley, T.; Lee, P. D.

    2015-06-01

    Uniaxial compression and indentation of a semi-solid Al-15wt.%Cu alloy was investigated by high speed synchrotron X-ray microtomography, quantifying the microstructural response of a solidifying alloy to applied strain. Tomograms were continuously acquired whilst performing deformation using a precision thermal-mechanical rig on a synchrotron beamline. The results illustrate how defects and shear bands can form in response to different loading conditions. Using digital volume correlation, the global and localised strains were measured, providing quantitative datasets for granular flow models of semi-solid deformation.

  13. Chemical analyses of pore water from boreholes USW SD-6 and USW WT-24, Yucca Mountain, Nevada

    USGS Publications Warehouse

    Yang, I.C.; Peterman, Z.E.; Scofield, K.M.

    2003-01-01

    Analyses of pore water extracted from cores of boreholes USW SD-6 in the central part and USW WT-24 in the northern part of Yucca Mountain, Nevada, show significant vertical and lateral variations in dissolved-ion concentrations. Analyses of samples of only a few milliliters of pore water extracted by uniaxial or triaxial compression and by ultracentrifugation methods from adjacent core samples are generally in agreement, within the analytical error of 10% to 15%. However, the values of silica for water obtained by ultracentrifugation are consistently lower than values for water obtained by compression. The larger concentrations probably are due to localized pressure solution of silicate minerals during compression. The shallower water from core in borehole USW SD-6 was extracted from nonwelded units collectively referred to as the Paintbrush Tuff nonwelded (PTn). The deeper water was from core in both boreholes USW SD-6 and USW WT-24 in the nonwelded units referred to as the Calico Hills nonwelded (CHn). Significant differences in mean dissolved-ion concentrations in pore water between the PTn and CHn are (1) decreases in Ca, Mg, SO4, and NO3 and (2) increases in HCO3 and (Na+K)/(Ca+Mg) ratios. The decrease in NO3 and the increase in HCO3 could be the result of denitrification through the oxidation of organic matter. The decrease in Ca and associated increase in (Na+K)/(Ca+Mg) is the result of ion exchange with zeolites in the CHn in borehole USW WT-24. This effect is not nearly as pronounced in borehole USW SD-6, probably reflecting a smaller amount of zeolitization of the CHn in USW SD-6. Geochemical calculations using the PHREEQC code indicate that the pore water from both boreholes USW SD-6 and USW WT-24 is uniformly undersaturated in anhydrite, gypsum, and amorphous silica, but supersaturated in quartz and chalcedony. The saturation of calcite, aragonite, sepiolite, and dolomite is more variable from sample to sample. ?? 2002 Elsevier Science B.V. All rights

  14. Processing, Microstructure and Mechanical Behavior of Ultrasonic Assisted Cast Magnesium 1wt% Silicon Carbide Nano-Composites

    NASA Astrophysics Data System (ADS)

    Erman, Ari

    The goal of this dissertation is to establish an understanding of processing -- microstructure -- mechanical behavior relationship in Mg-1wt% SiC metal matrix nano-composites fabricated via an ultrasonic assisted casting process, with the emphasis on the effect of the distribution of nanoparticles on this relationship. Ultrasonic assisted casting has been proved as an effective technique to distribute nanoparticles in Mg metal matrix nano-composites (MMNCs). Mg MMNCs reinforced with 1 wt% SiC nanoparticles, were cast by ultrasonic cavitation-based dispersion methods. Microstructural analyses of as cast specimens were conducted to characterize the grain size, shape and distribution, SiC nanoparticle size and distribution, and nanoparticle-matrix interface. Average grain size for the ultrasonic assisted cast composite specimens was 72 mum compared to 181 mum for pure Mg samples prepared by the same method. The average measured SiC nanoparticle size was 66 nm. TEM studies showed good local dispersion of SiC nanoparticles, with only a few small, widely spaced clusters. HRTEM showed a clean interface between SiC nanoparticles and the Mg matrix, with no evidence of secondary phases. The yield strength of Mg-1 wt% SiC nanocomposites was 67 MPa, which showed improvement from 47 MPa for the pure Mg samples. This extra strengthening is due to Orowan and Hall-Petch effects. Fatigue experiments were conducted to characterize the cyclic stress-strain response of pure Mg and Mg-1wt% SiC samples at 0.2%, 0.4% and 0.6% plastic strain amplitudes. The analyses of the cyclic stress response curves and hysteresis loops, combined with post failure TEM analyses provided an understanding of the role of twinning, and twin-particle interactions on the cyclic deformation behavior of Mg MMNCs. Tensile twinning and basal slip are the main forms of deformation mechanisms under compression, followed by detwinning and basal slip in subsequent tension. Fatigue lives of Mg MMNCs are comparable to

  15. Experimental Study on Shear Response of 92.93 WT% Alumina Under Combined Pressure-Shear Loading

    NASA Astrophysics Data System (ADS)

    Yao, G. W.; Liu, Z. F.

    2007-12-01

    Pressure-shear plate impact experiments and soft recovery experiments were performed for 92.93 wt% aluminas with 75-mm-diameter compressed-gas gun. The in-material longitudinal and transverse particle velocities were traced by the embedded electromagnetic velocity gauges. The decoupled transverse particle velocities show an attenuation of shear waves with decreasing of material shear rigidity. SEM analysis of the intact samples shows heterogeneous meso-structures, and that of recovered samples shows the transit of intergranular microcracks to transgranular microcracks with increasing shock loading. The transverse shear promotes the microcracks nuclearing and expanding, and these microcracks result in remarkable dilation of alumina samples after unloading.

  16. Development of Highly Ductile Spheroidized Steel from High C (0.61 wt.% C) Low-Alloy Steel

    NASA Astrophysics Data System (ADS)

    Monia, S.; Varshney, A.; Gouthama; Sangal, S.; Kundu, S.; Samanta, S.; Mondal, K.

    2015-11-01

    This research aims to develop a multiphase steel combining spheroidal cementite and bainite in ductile ferrite matrix possessing an optimal balance of reasonably high strength and excellent ductility. A high carbon (0.61 wt.%) high silicon (1.71 wt.%) EN45 spring steel was annealed to obtain ferrite pearlite microstructure. The samples were given 5 and 10% cold rolling followed by holding at temperature below Ac1 for about 3 h. The samples were then held in intercritical range at 770 °C temperature for different durations ranging from 5 to 20 min for partial re-austenitization followed by quenching in a salt bath maintained at 350 °C and holding for 10 min to get bainite. The samples were finally water quenched. Characterizations of the samples with the help of optical microscopy, x-ray diffraction, scanning electron microscopy, and atomic force microscopy were carried out. Optimal heat-treatment conditions were found out after correlating with tensile properties. The best combination of high tensile strength (~800 MPa) with very high elongation (~29%) was obtained. Effects of cold-rolled strain and holding time in the intercritical region on the mechanical properties and microstructural changes were studied. Finally, structural property correlation is established.

  17. Cube texture formation during the early stages of recrystallization of Al-1%wt.Mn and AA1050 aluminium alloys

    NASA Astrophysics Data System (ADS)

    Miszczyk, M. M.; Paul, H.

    2015-08-01

    The cube texture formation during primary recrystallization was analysed in plane strain deformed samples of a commercial AA1050 alloy and an Al-1%wt.Mn model alloy single crystal of the Goss{110}<001> orientation. The textures were measured with the use of X-ray diffraction and scanning electron microscopy equipped with an electron backscattered diffraction facility. After recrystallization of the Al-1%wt.Mn single crystal, the texture of the recrystallized grains was dominated by four variants of the S{123}<634> orientation. The cube grains were only sporadically detected by the SEM/EBSD system. Nevertheless, an increased density of <111> poles corresponding to the cube orientation was observed. The latter was connected with the superposition of four variants of the S{123}<634> orientation. This indicates that the cube texture after the recrystallization was a ‘compromise texture’. In the case of the recrystallized AA1050 alloy, the strong cube texture results from both the increased density of the particular <111> poles of the four variants of the S orientation and the ∼40°(∼< 111>)-type rotation. The first mechanism transforms the Sdef-oriented areas into Srex ones, whereas the second the near S-oriented, as-deformed areas into near cube-oriented grains.

  18. Production of light olefins by catalytic conversion of lignocellulosic biomass with HZSM-5 zeolite impregnated with 6wt.% lanthanum.

    PubMed

    Huang, Weiwei; Gong, Feiyan; Fan, Minghui; Zhai, Qi; Hong, Chenggui; Li, Quanxin

    2012-10-01

    Catalytic conversion of rice husk, sawdust, sugarcane bagasse, cellulose, hemicellulose and lignin into olefins was performed with HZSM-5 containing 6 wt.% lanthanum. The olefins yields for different feedstocks decreased in the order: cellulose>hemicellulose>sugarcane bagasse>rice husk>sawdust>lignin. Biomass containing higher content of cellulose or hemicellulose produced more olefins than feedstocks with higher content of lignin. Among the biomass types, sugarcane bagasse provided the highest olefin yield of 0.12 kg olefins/(kg dry biomass) and carbon yield of 21.2C-mol%. Temperature, residence time and the catalyst/feed ratio influenced olefin yield and selectivity. While the HZSM-5 zeolite was catalytically active, the incorporation of lanthanum at 2.9, and 6.0 wt.% increased the production of olefins from rice husk by 15.6% and 26.5%, respectively. The conversion of biomass to light olefins potentially provides an alternative and sustainable route for production of the key petrochemicals. PMID:22858493

  19. α-Phase transformation kinetics of U – 8 wt% Mo established by in situ neutron diffraction

    DOE PAGESBeta

    Garlea, Elena; Steiner, M. A.; Calhoun, C. A.; Klein, R. W.; An, K.; Agnew, S. R.

    2016-05-08

    The α-phase transformation kinetics of as-cast U - 8 wt% Mo below the eutectoid temperature have been established by in situ neutron diffraction. α-phase weight fraction data acquired through Rietveld refinement at five different isothermal hold temperatures can be modeled accurately utilizing a simple Johnson-Mehl-Avrami-Kolmogorov impingement-based theory, and the results are validated by a corresponding evolution in the γ-phase lattice parameter during transformation that follows Vegard’s law. Neutron diffraction data is used to produce a detailed Time-Temperature-Transformation diagram that improves upon inconsistencies in the current literature, exhibiting a minimum transformation start time of 40 min at temperatures between 500 °Cmore » and 510 °C. Lastly, the transformation kinetics of U – 8 wt% Mo can vary significantly from as-cast conditions after extensive heat treatments, due to homogenization of the typical dendritic microstructure which possesses non-negligible solute segregation.« less

  20. Transcriptional Regulation by the Wilms Tumor Protein, Wt1, Suggests a Role of the Metalloproteinase Adamts16 in Murine Genitourinary Development*

    PubMed Central

    Jacobi, Charlotte L. J.; Rudigier, Lucas J.; Scholz, Holger; Kirschner, Karin M.

    2013-01-01

    ADAMTS16 (a disintegrin and metalloproteinase with thrombospondin motifs) is a secreted mammalian metalloproteinase with unknown function. We report here that murine Adamts16 is co-expressed with the Wilms tumor protein, Wt1, in the developing glomeruli of embryonic kidneys. Adamts16 mRNA levels were significantly reduced upon transfection of embryonic murine kidney explants with Wt1 antisense vivo-morpholinos. Antisense knockdown of Adamts16 inhibited branching morphogenesis in kidney organ cultures. Adamts16 was detected by in situ mRNA hybridization and/or immunohistochemistry also in embryonic gonads and in spermatids and granulosa cells of adult testes and ovaries, respectively. Silencing of Wt1 by transfection with antisense vivo-morpholinos significantly increased Adamts16 mRNA in cultured embryonic XY gonads (11.5 and 12.5 days postconception), and reduced Adamts16 transcripts in XX gonads (12.5 and 13.5 days postconception). Three predicted Wt1 consensus motifs could be identified in the promoter and the 5′-untranslated region of the murine Adamts16 gene. Binding of Wt1 protein to these elements was verified by EMSA and ChIP. A firefly luciferase reporter gene under control of the Adamts16 promoter was activated ∼8-fold by transient co-transfection of human granulosa cells with a Wt1 expression construct. Gradual shortening of the 5′-flanking sequence successively reduced and eventually abrogated Adamts16 promoter activation by Wt1. These findings demonstrate that Wt1 differentially regulates the Adamts16 gene in XX and XY embryonic gonads. It is suggested that Adamts16 acts immediately downstream of Wt1 during murine urogenital development. We propose that Adamts16 is involved in branching morphogenesis of the kidneys in mice. PMID:23661704

  1. POTENTIAL FOR NITROSAMINE FORMATION RESULTING FROM THE USE OF RHODAMINE WT FOR TIME-OF-TRAVEL STUDIES: A COMBINED LABORATORY AND FIELD INVESTIGATION.

    USGS Publications Warehouse

    Johnson, Sharon M.; Steinheimer, Thomas R.

    1984-01-01

    Rhodamine WT is used by surface water hydrologists for time of travel and dispersion studies in which flow characteristics of surface streams are determined. Surface water contamination by nitrosamines formed from Rhodamine WT and nitrite ion has been studied. A method for residue analysis of N-nitrosodiethylamine (NDEA) has been developed and evaluated using river samples spiked with Rhodamine WT and nitrite ion. It permits rapid and reliable determination of NDEA at a minimum concentration of 0. 03 mu g/L. The method uses solid-phase extraction and capillary gas chromatography.

  2. Formation of ZrO{sub 2} in coating on Mg–3 wt.%Al–1 wt.%Zn alloy via plasma electrolytic oxidation: Phase and structure of zirconia

    SciTech Connect

    Lee, Kang Min; Kim, Yeon Sung; Yang, Hae Woong; Park, Joo Hyun; Ko, Young Gun; Shin, Dong Hyuk

    2015-01-15

    An investigation of the coating structure formed on Mg–3 wt.%Al–1 wt.%Zn alloy sample subjected to plasma electrolytic oxidation was examined by field-emission transmission electron microscopy. The plasma electrolytic oxidation process was conducted in a phosphoric acid electrolyte containing K{sub 2}ZrF{sub 6} for 600 s. Microstructural observations showed that the coating consisting of MgO, MgF{sub 2}, and ZrO{sub 2} phases was divided into three distinctive parts, the barrier, intermediate, and outer layers. Nanocrystalline MgO and MgF{sub 2} compounds were observed mainly in the barrier layer of ~ 1 μm thick near to the substrate. From the intermediate to outer layers, various ZrO{sub 2} polymorphs appeared due to the effects of the plasma arcing temperature on the phase transition of ZrO{sub 2} compounds during the plasma electrolytic oxidation process. In the outer layer, MgO compound grew in the form of a dendrite-like structure surrounded by cubic ZrO{sub 2}. - Highlights: • The barrier layer containing MgO and MgF{sub 2} was observed near to the Mg substrate. • In the intermediate layer, m-, t-, and o-ZrO{sub 2} compounds were additionally detected. • The outer layer contained MgO with the dendrite-like structure surrounded by c-ZrO{sub 2}. • The grain sizes of compounds in oxide layer increased from barrier to outer layer.

  3. Changes in the heat of melting of a superelastic eutectic Sn-38 wt % Pb alloy due to preliminary plastic deformation

    NASA Astrophysics Data System (ADS)

    Korshak, V. F.; Postavnichii, I. V.; Tkachenko, N. V.

    2015-10-01

    The effect of an external compressing stress applied in the process of heating from room temperature to the preeutectic temperature on the specific heat of melting of an alloy Sn-38 wt % Pb has been investigated. The chosen stress range of 0-7.5 MPa includes stresses at which the alloy manifests superplastic properties. The experiments were conducted using the differential thermal analysis method. For the first time, a nonmonotonic dependence of the specific heat of melting of superplastic eutectic alloys on the magnitude of applied stress has been detected. These results have been explained by the metastability of the initial phase state of the alloy and by the stimulating influence of the plastic deformation depending on the level of external stresses on the processes providing a transition of the alloy to the equilibrium state.

  4. Effects of Hot Rolling on Low-Cycle Fatigue Properties of Zn-22 wt.% Al Alloy at Room Temperature

    NASA Astrophysics Data System (ADS)

    Dong, X. H.; Cao, Q. D.; Ma, S. J.; Han, S. H.; Tang, W.; Zhang, X. P.

    2016-06-01

    The effects of the reduction ratio (RR) on the low-cycle fatigue (LCF) properties of the Zn-22 wt.% Al (Zn-22Al) alloy were investigated. Various grain sizes from 0.68 to 1.13 μm were obtained by controlled RRs. Tensile and LCF tests were carried out at room temperature. Superplasticity and cyclic softening were observed. Strength and ductility of the rolled Zn-22Al alloy increased with the RR, owing to the decrease in its grain size. The RR did not affect the cyclic softening behavior of the alloy. The fatigue life of the alloy decreased with increasing strain amplitude, while the fatigue life first decreased and then increased with increasing RR. The longest fatigue life was observed for the alloy rolled at a RR of 60%. A bilinear Coffin-Manson relationship was observed to hold true for this alloy.

  5. Heterogeneous nucleation of the primary phase in the rapid solidification of Al-4.5wt%Cu alloy droplet

    NASA Astrophysics Data System (ADS)

    Maitre, A.; Bogno, A.-A.; Bedel, M.; Reinhart, G.; Henein, H.

    2015-06-01

    This paper reports on rapid solidification of Al-Cu alloys. A heterogeneous nucleation/growth model coupled with a thermal model of a falling droplet through a stagnant gas was developed. The primary undercooling as well as the number of nucleation points was compared with Al-Cu alloy droplets produced by Impulse Atomization (IA). Based on experimental results from Neutron Diffraction, secondary (eutectic) phases were obtained. Then, primary and secondary undercoolings were estimated using the metastable extensions of solidus and liquidus lines calculated by Thermo-Calc. Moreover, Synchrotron X-ray microtomography has been performed on Al-4.5wt%Cu droplets. The undercoolings are in good agreement. Results also evidence the presence of one nucleation point and are in agreement with the experimental observations.

  6. Microstructure and texture evolution of strip casting 3 wt% Si non-oriented silicon steel with columnar structure

    NASA Astrophysics Data System (ADS)

    Liu, Haitao; Liu, Zhenyu; Cao, Guangming; Li, Chenggang; Wang, Guodong

    2011-11-01

    An Fe-3 wt%Si strip with columnar structure and pronounced {0 0 1}<0 v w> texture was produced using a twin-roll strip caster. Then the as-cast strip was cold-rolled and annealed. The microstructure and texture evolution along the processing steps was investigated. It is found that inhomogeneous microstructure is produced in both cold-rolled and final annealed samples due to the large initial grains. The cold rolling texture is dominated by pronounced a-fiber texture and relatively strong γ-fiber texture. The final recrystallization texture is characterized by {0 0 1}<0 1 0>, {0 0 1}<2 1 0>, {1 1 0}<0 0 1> texture and a slightly shifted {1 1 1}<1 1 2> component. The microstructural inhomogeneity plays an important role in the texture evolution.

  7. Evaluation of the MICAST #2-12 AI-7wt%Si Sample Directionally Solidified Aboard the International Space Station

    NASA Technical Reports Server (NTRS)

    Tewari, Surendra N.; Ghods, Masoud; Angart, Samuel G.; Lauer, Mark; Grugel, Richard N.; Poirier, David R.

    2016-01-01

    The US team of the European led "MIcrostructure Formation in CASTing of Technical Alloys under Diffusive and Magnetically Controlled Convective Conditions" (MICAST) program recently received a third Aluminum - 7wt% silicon alloy that was processed in the microgravity environment aboard the International Space Station. The sample, designated MICAST#2-12, was directionally solidified in the Solidification with Quench Furnace (SQF) at a constant rate of 40micometers/s through an imposed temperature gradient of 31K/cm. Procedures taken to evaluate the state of the sample prior to sectioning for metallographic analysis are reviewed and rational for measuring the microstructural constituents, in particular the primary dendrite arm spacing (Lambda (sub1)), is given. The data are presented, put in context with the earlier samples, and evaluated in view of a relevant theoretical model.

  8. Corrosion Inhibition Performance of Triazole Derivatives on Copper-Nickel Alloy in 3.5 wt.% NaCl Solution

    NASA Astrophysics Data System (ADS)

    Jiang, B.; Jiang, S. L.; Liu, X.; Ma, A. L.; Zheng, Y. G.

    2015-12-01

    This study investigates the performance of three triazole derivatives with different molecular structures as corrosion inhibitors for the copper-nickel alloy CuNi 90/10 in 3.5 wt.% NaCl solution. Inhibition behavior was systematically determined through electrochemical measurements, scanning electron microscopy, energy-dispersive spectroscopy, and Fourier transform infrared spectroscopy. In addition, adsorption behavior and the inhibition mechanism were investigated via quantum chemical calculation and molecular dynamic simulation. Experimental results indicate that the three inhibitors with triazole rings and heteroatoms exhibited excellent corrosion inhibition capabilities on the copper-nickel alloy surface through physisorption and chemisorption. In particular, 3-amino-5-mercapto-1,2,4-triazole showed the best inhibition capability according to the concentration ranges considered in the experiments. The results of quantum chemical calculation agreed with the experimental findings.

  9. Plasma spray coating of spray-dried Cr2O3/wt.% TiO2 powder

    NASA Astrophysics Data System (ADS)

    Kim, B. K.; Lee, D. W.; Ha, G. H.

    2001-03-01

    An agglomerated Cr2O3/wt.%TiO2 powder has been fabricated by the spray drying process under different parameters. The spray-dried powder has well-agglomerated particles of spherical shape. In the conditions of the high slurry feed rate and low binder concentration in the slurry, the powder has large cavities inside some particles and ruggedness over their surface. The optimum plasma spray feed rate has been found by examining the spraying behavior of the powder and melted state of particles. The plasma spray coating has been performed under different process variables such as spraying distance and plasma power. These parameters strongly affect the characteristics of the coated layer: microstructure, hardness, and bond strength.

  10. 3D simulation of interdendritic flow through a Al-18wt.%Cu structure captured with X-ray microtomography

    NASA Astrophysics Data System (ADS)

    Domitner, J.; Hölzl, C.; Kharicha, A.; Wu, M.; Ludwig, A.; Köhler, M.; Ratke, L.

    2012-01-01

    A central parameter to describe the formation of porosity and macrosegregation during casting processes is the permeability of the dendritic mushy zone. To determine this specific feature for a binary Al-18wt.%Cu alloy, flow simulations based on the Lattice Boltz-mann (LB) method were performed. The LB method allows an efficient solving of fluid flow problems dealing with complex shapes within an acceptable period of time. The 3D structure required as input for the simulations was captured with X-ray microtomography, which enables the generation of representative geometries for permeability investigations. Removing the eutectic phase from the measured dataset generated a remaining network of solid primary dendrites. In the simulations, a pressure gradient was applied to force the liquid through the free interdendritic channels. The permeability of the structure was then calculated from the resulting flow velocity pattern using Darcy's law. To examine the influence of different boundary conditions on the results obtained, several simulations were conducted.

  11. A CTCF-binding silencer regulates the imprinted genes AWT1 and WT1-AS and exhibits sequential epigenetic defects during Wilms' tumourigenesis.

    PubMed

    Hancock, Anne L; Brown, Keith W; Moorwood, Kim; Moon, Hanlim; Holmgren, Claes; Mardikar, Sudhanshu H; Dallosso, Anthony R; Klenova, Elena; Loukinov, Dmitri; Ohlsson, Rolf; Lobanenkov, Victor V; Malik, Karim

    2007-02-01

    We have shown previously that AWT1 and WT1-AS are functionally imprinted in human kidney. In the adult kidney, expression of both transcripts is restricted to the paternal allele, with the silent maternal allele retaining methylation at the WT1 antisense regulatory region (WT1 ARR). Here, we report characterization of the WT1 ARR differentially methylated region and show that it contains a transcriptional silencer element acting on both the AWT1 and WT1-AS promoters. DNA methylation of the silencer results in increased transcriptional repression, and the silencer is also shown to be an in vitro and in vivo target site for the imprinting regulator protein CTCF. Binding of CTCF is methylation-sensitive and limited to the unmethylated silencer. Potentiation of the silencer activity is demonstrated after CTCF protein is knocked down, suggesting a novel silencer-blocking activity for CTCF. We also report assessment of WT1 ARR methylation in developmental and tumour tissues, including the first analysis of Wilms' tumour precursor lesions, nephrogenic rests. Nephrogenic rests show increases in methylation levels relative to foetal kidney and reductions relative to the adult kidney, together with biallelic expression of AWT1 and WT1-AS. Notably, the methylation status of CpG residues within the CTCF target site appears to distinguish monoallelic and biallelic expression states. Our data suggest that failure of methylation spreading at the WT1 ARR early in renal development, followed by imprint erasure, occurs during Wilms' tumourigenesis. We propose a model wherein imprinting defects at chromosome 11p13 may contribute to Wilms' tumourigenesis. PMID:17210670

  12. Estimation of molecular upper remission limit for monitoring minimal residual disease in peripheral blood of acute myeloid leukemia patients by WT1 expression

    PubMed Central

    POLÁK, JAROSLAV; HÁJKOVÁ, HANA; MAALAUFOVÁ-SOUKUPOVÁ, JACQUELINE; MARKOVÁ, JANA; ŠÁLEK, CYRIL; SCHWARZ, JIŘÍ; HAŠKOVEC, CEDRIK

    2012-01-01

    To date, approximately one half of acute myeloid leukaemia (AML) patients do not have a suitable specific molecular marker for monitoring minimal residual disease (MRD). The Wilm’s tumour gene (WT1) has been suggested as a possible molecular marker of MRD in AML. The expression of WT1 in peripheral blood (PB) was measured using quantitative real-time reverse transcription-polymerase chain reaction in peripheral leukocytes from 151 patients with AML at diagnosis. WT1 expression was significantly elevated, i.e. up to 3 orders of magnitude in the majority (80%) of AML patients at diagnosis compared to the PB of healthy donors. Sequence samples of the long-term followed-up AML patients treated with chemotherapy and/or allogeneic bone marrow transplantation were analysed for WT1 expression. The results revealed that the hematological relapses were preceded (median, 1.8 months) by an increase in WT1 gene expression. For the practical utility of this gene as a molecular marker of relapse, it was necessary to determine an upper remission limit, crossing which would signal hematological relapse. The upper remission limit was determined in our set of patients to be 0.02 WT1/ABL. The AML patients who consequently relapsed crossed this upper remission limit; however, those in permanent remission did not. Therefore, this upper remission limit could be taken as the border of molecular relapse of AML patients. Moreover, insufficient decline of WT1 expression under the upper remission limit following induction and/or consolidation therapy was associated with markedly high risk of relapse. The results show that our upper remission limit can be taken as the border of molecular relapse of AML patients and WT1 levels following initial therapy as a beneficial prognostic marker. PMID:22969857

  13. Genotype differences in anxiety and fear learning and memory of WT and ApoE4 mice associated with enhanced generation of hippocampal reactive oxygen species.

    PubMed

    Villasana, Laura E; Weber, Sydney; Akinyeke, Tunde; Raber, Jacob

    2016-09-01

    Apolipoprotein E (apoE), involved in cholesterol and lipid metabolism, also influences cognitive function and injury repair. In humans, apoE is expressed in three isoforms. E4 is a risk factor for age-related cognitive decline and Alzheimer's disease, particularly in women. E4 might also be a risk factor for developing behavioral and cognitive changes following (56) Fe irradiation, a component of the space environment astronauts are exposed to during missions. These changes might be related to enhanced generation of reactive oxygen species (ROS). In this study, we compared the behavioral and cognitive performance of sham-irradiated and irradiated wild-type (WT) mice and mice expressing the human E3 or E4 isoforms, and assessed the generation of ROS in hippocampal slices from these mice. E4 mice had greater anxiety-like and conditioned fear behaviors than WT mice, and these genotype differences were associated with greater levels of ROS in E4 than WT mice. The greater generation of ROS in the hippocampus of E4 than WT mice might contribute to their higher anxiety levels and enhanced fear conditioning. In E4, but not WT, mice, phorbol-12-myristate-13-acetate-treated hippocampal slices showed more dihydroxy ethidium oxidation in sham-irradiated than irradiated mice and hippocampal heme oxygenase-1 levels were higher in irradiated than sham-irradiated E4 mice. Mice with apolipoprotein E4 (E4), a risk factor for Alzheimer's disease, have greater anxiety-like and conditioned fear behaviors than wild-type (WT) mice. Generation of reactive oxygen species (ROS, in red) 3 months following (56) Fe irradiation, a component of the space environment astronauts are exposed to, is more pronounced in the hippocampus of E4 than WT mice. In E4, but not WT, mice, hippocampal levels of the oxidative stress-relevant marker heme oxygenase-1 are higher in irradiated than sham-irradiated E4 mice. PMID:27412623

  14. TTP SR1-6-WT-31, Milestone C.3-2 annual report on Clemson/INEEL melter work. Revision 1

    SciTech Connect

    Bickford, D.F.

    1999-12-17

    This work is performed in collaboration with RL37WT31-C and ID77WT31-B. During the first two years of radioactive operation of the DWPF process, several areas for improvement in melter design have been identified. The continuing scope of this task is to address performance limitations and deficiencies identified by the user. SRS will design and test several configurations of the melter pour spout and associated equipment to improve consistency of performance and recommend design improvements.

  15. A clinical and immunologic phase 2 trial of Wilms tumor gene product 1 (WT1) peptide vaccination in patients with AML and MDS.

    PubMed

    Keilholz, Ulrich; Letsch, Anne; Busse, Antonia; Asemissen, Anne Marie; Bauer, Sandra; Blau, Igor Wolfgang; Hofmann, Wolf-Karsten; Uharek, Lutz; Thiel, Eckhard; Scheibenbogen, Carmen

    2009-06-25

    This study investigated the immunogenicity of Wilms tumor gene product 1 (WT1)-peptide vaccination in WT1-expressing acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS) patients without curative treatment option. Vaccination consisted of granulocyte-macrophage colony-stimulating factor subcutaneously days 1 to 4, and WT1.126-134 peptide and 1 mg keyhole limpet hemocyanin on day 3. The initial 9 patients received 4 vaccinations biweekly, then monthly, and the subsequent 10 patients received continual biweekly vaccination. Seventeen AML patients and 2 refractory anemia with excess blasts patients received a median of 11 vaccinations. Treatment was well tolerated. Objective responses in AML patients were 10 stable diseases (SDs) including 4 SDs with more than 50% blast reduction and 2 with hematologic improvement. An additional 4 patients had clinical benefit after initial progression, including 1 complete remission and 3 SDs. WT1 mRNA levels decreased at least 3-fold from baseline in 35% of patients. In 8 of 18 patients, WT1-tetramer(+) T cells increased in blood and in 8 of 17 patients in bone marrow, with a median frequency in bone marrow of 0.18% at baseline and 0.41% in week 18. This WT1 vaccination study provides immunologic, molecular, and preliminary evidence of potential clinical efficacy in AML patients, warranting further investigations. PMID:19389880

  16. Characterization of the genomic breakpoint and chimeric transcripts in the EWS-WT1 gene fusion of desmoplastic small round cell tumor.

    PubMed Central

    Gerald, W L; Rosai, J; Ladanyi, M

    1995-01-01

    Desmoplastic small round cell tumor is a recently recognized distinctive tumor shown to be associated with a recurrent translocation, t(11;22)(p13;q12), and rearrangement of the genes for Ewing sarcoma (EWS) and Wilms tumor (WT1). A genomic DNA fragment containing the EWS-WT1 gene fusion has been isolated from a desmoplastic small round cell tumor, and the breakpoint has been characterized. The breakpoints involve the intron between EWS exons 7 and 8 and the intron between WT1 exons 7 and 8. Chimeric transcripts corresponding to the fusion gene were detected in four of six cases studied. Analysis of these transcripts show an in-frame fusion of RNA encoding the amino-terminal domain of EWS to both alternatively spliced forms of the last three zinc fingers of the DNA-binding domain of WT1. Desmoplastic small round cell tumor represents the third tumor type associated with translocation of EWS and the first tumor associated with consistent translocation of WT1. The chimeric products are predicted to modulate transcription at WT1 target sites and contribute to development of this unique tumor. Images Fig. 1 Fig. 2 Fig. 3 PMID:7862627

  17. Microstructure evolution and tensile properties of Zr-2.5 wt.% Nb pressure tubes processed from billets with different microstructures

    SciTech Connect

    Kapoor, K.; Saratchandran, N.; Muralidharan, K.

    1999-02-01

    Pressurized heavy water reactors (PHWR) use zirconium-base alloys for their low neutron-absorption cross section, good mechanical strength, low irradiation creep, and high corrosion resistance in reactor atmospheres. Starting with identical ingots, billets having different microstructures were obtained by three different processing methods for fabrication of Zr-2.5 wt%Nb pressure tubes., The billets were further processed by hot extrusion and cold Pilger tube reducing to the finished product. Microstructural characterization was done at each stage of processing. The effects of the initial billet microstructure on the intermediate and final microstructure and mechanical property results were determined. It was found that the structure at each stage and the final mechanical properties depend strongly on the initial billet microstructure. The structure at the final stage consists of elongated alpha zirconium grains with a network of metastable beta zirconium phase. Some of this metastable phase transforms into stable beta niobium during thermomechanical processing. Billets with quenched structure resulted in less beta niobium at the final stage. The air cooled billets resulted in a large amount of beta niobium. The tensile properties, especially the percentage elongation, were found to vary for the different methods. Higher percentage elongation was observed for billets having quenched structure. Extrusion and forging did not produce any characteristic differences in the properties. The results were used to select a process flow sheet which yields the desired mechanical properties with suitable microstructure in the final product.

  18. Investigation of in-reactor creep and irradiation growth of zirconium-2.5 wt% niobium channel tubes

    NASA Astrophysics Data System (ADS)

    Goncharov, V. V.; Platonov, P. A.; Ivanov, A. N.; Frolov, I. A.

    1980-05-01

    We summarize the diametral creep results obtained in the MR reactor of the Kurchatov Institute of Atomic Energy on zirconium-2.5 wt% niobium pressure tubes of the type used in RBMK-1000 power reactors. The experiments that lasted up to 30 000 h cover a temperature range of 270 to 350°C, neutron fluxes between 0.6 and 4.0 ×10 13n/ cm2 · s ( E > 1 MeV) and stresses of up to 16 kgf/mm 2. Diametral strains of up to 4.8% have been measured. In-reactor creep results have been analyzed in terms of thermal and irradiation creep components assuming them to be additive. The thermal creep rate is given by a relationship of the type ɛth = A1exp [( A2 + A3 σt) T] and the irradiation component by ɛrad = A4 σtø( T - A5), where T = temperature, σ t = hoop stress, ø = neutron flux and a1 to A5 are constants. Irradiation growth experiments carried out at 280° C on specimens machined from pressure tubes showed a non-linear dependence of growth strain on neutron fluence up to neutron fluences of 5 × 10 20 n/cm 2. The significance of these results to the elongation of RBMK reactor pressure tubes is discussed.

  19. Effect of carbon and oxygen on microstructure and mechanical properties of Ti-25V-15Cr-2Al (wt%) alloys

    SciTech Connect

    Li, Y.G.; Blenkinsop, P.A.; Loretto, M.H.; Rugg, D.; Voice, W.

    1999-08-10

    The effect of carbon additions on microstructure and mechanical properties of alloys with different levels of oxygen was studied in {beta} titanium alloys of the general composition Ti-25V-15Cr-2Al (all compositions are in wt% unless otherwise indicated). The microstructures were studied using optical microscopy (OM), X-ray diffractometry (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). It was found that titanium carbides with vacancy-ordered structure formed in all alloys with C additions of over 1,000 w.p.p.m. Grains were refined by carbides.Wavelength-dispersive X-ray (WDX) analysis showed that oxygen was much higher in carbides than in {beta} matrix. After long-term exposure at 550 C {alpha} precipitation was significantly reduced in samples with titanium carbides compared with those without. A significant improvement in room temperature tensile ductility was achieved by the addition of carbon to the alloys. Elongations of {approximately} 10% were obtained in samples which were exposed at 550 C for 500 h following heat treatments at 1,050 and 700 C.

  20. Ageing characteristics of the metastable gamma phase in U-9 wt.% Mo alloy: experimental observations and thermodynamic validation

    NASA Astrophysics Data System (ADS)

    Neogy, S.; Saify, M. T.; Jha, S. K.; Srivastava, D.; Dey, G. K.

    2015-09-01

    Ageing characteristics of the metastable bcc γ-phase in U-9 wt.% Mo alloy, a candidate for high uranium density nuclear fuel for research and test reactors, have been investigated in this study. Analyses of the aged microstructures, employing X-ray diffraction and various microscopy techniques, revealed the decomposition mechanism of the metastable γ-phase to the stable α-U and γ‧ (U2Mo) phases. A discontinuous precipitation reaction, leading to the generation of partially transformed cellular colonies with lamellae comprising of either the α-phase or the γ‧-phase in γ-phase matrix, was found to be operative. The in situ transformation of γ interlamellar regions to the γ‧-phase was noticed occasionally within the γ + α lamellar colonies. Thermodynamic analysis of the U-Mo system, using free energy-composition diagrams, could associate the observed attributes of the decomposition of γ-phase to the extent of Mo segregation and the chemical driving force required for the nucleation of α- and γ‧-phases in the γ-matrix.

  1. Evolution of the dendritic morphology with the solidification velocity in rapidly solidified Al-4.5wt.%Cu droplets

    NASA Astrophysics Data System (ADS)

    Bedel, M.; Reinhart, G.; Gandin, Ch-A.; Bogno, A.-A.; Nguyen-Thi, H.; Henein, H.

    2015-06-01

    The microstructure morphology of Al-4.5wt.%Cu droplets formed by the Impulse Atomization technique is investigated. Three-dimensional reconstructions by synchrotron X- ray micro-tomography of several droplets reveal different morphologies in droplets of similar diameter and produced in the same batch. Moreover, microstructural features also indicate that the development of the dendrite arms occurs in some droplets along <111> crystallographic axes instead of the usual <100> directions observed in conventional casting for the same alloy. It has been observed that such an unusual growth direction of the dendrites is directly related to the solidification velocity. We underpin these results by carrying out comparisons with a solidification model. Predictions are used to discuss the change of dendrite growth direction, as well as the existence of a dendrite growth direction range for a given type of droplets. In addition, the effect of the droplet size and the cooling gas on the dendrite growth direction range observed experimentally is also investigated by using the model.

  2. Solidification analysis of a centrifugal atomizer using the Al-32.7wt.percent Cu alloy

    NASA Astrophysics Data System (ADS)

    Osborne, Matthew Gary

    1997-12-01

    A centrifugal atomizer (spinning disk variety) was designed and constructed for the production of spherical metal powders, 100-1000 microns in diameter in an inert atmosphere. Initial atomization experiments revealed the need for a better understanding of how the liquid metal was atomized and how the liquid droplets solidified. To investigate particle atomization, Ag was atomized in air and the process recorded on high-speed film. To investigate particle solidification, Al-32.7wt.% Cu was atomized under inert atmosphere and the subsequent particles were examined microscopically to determine solidification structure and rate. This dissertation details the experimental procedures used in producing the Al-Cu eutectic alloy particles, examination of the particle microstructures, and determination of the solidification characteristics (e.g., solidification rate) of various phases. Finally, correlations are proposed between the operation of the centrifugal atomizer and the observed solidification spacings. This research was supported in part by the Office of Basic Energy Science, USDOE. The Ames laboratory is operated by Iowa State University for the U.S. Department of Energy under contract number W-7405-Eng-82.

  3. Thermomechanical process optimization of U-10 wt% Mo - Part 1: high-temperature compressive properties and microstructure

    NASA Astrophysics Data System (ADS)

    Joshi, Vineet V.; Nyberg, Eric A.; Lavender, Curt A.; Paxton, Dean; Garmestani, Hamid; Burkes, Douglas E.

    2015-10-01

    Nuclear power research facilities require alternatives to existing highly enriched uranium alloy fuel. One option for a high density metal fuel is uranium alloyed with 10 wt% molybdenum (U-10Mo). Fuel fabrication process development requires specific mechanical property data that, to date has been unavailable. In this work, as-cast samples were compression tested at three strain rates over a temperature range of 400-800 °C to provide data for hot rolling and extrusion modeling. The results indicate that with increasing test temperature the U-10Mo flow stress decreases and becomes more sensitive to strain rate. In addition, above the eutectoid transformation temperature, the drop in material flow stress is prominent and shows a strain-softening behavior, especially at lower strain rates. Room temperature X-ray diffraction and scanning electron microscopy combined with energy dispersive spectroscopy analysis of the as-cast and compression tested samples were conducted. The analysis revealed that the as-cast samples and the samples tested below the eutectoid transformation temperature were predominantly γ phase with varying concentration of molybdenum, whereas the ones tested above the eutectoid transformation temperature underwent significant homogenization.

  4. Correlation between microstructure and hardness of a Bi-1.5wt%Ag lead-free solder alloy

    NASA Astrophysics Data System (ADS)

    Spinelli, J. E.; Macedo, R. A.; Silva, B. L.; Garcia, A.

    2016-03-01

    In the present study a hypoeutectic Bi-1.5wt%Ag alloy was directionally solidified under transient heat flow conditions and the microstructure was analysed. Bi-Ag alloys are considered as potential alternatives to replace Pb-based alloys as solder materials for metallic connections under high temperatures. However, a lack of understanding regarding the effects of solidification thermal parameters (growth rate - VL, the cooling rate - Ṫ) on microstructural aspects is reported in literature. Another challenge is to improve properties and reliability. The results of the present study include the determination of the tip growth rate and the cooling rate by cooling curves recorded by thermocouples positioned along the casting length, metallography, X-ray fluorescence (XRF) and Vickers hardness. The entire directionally solidified Bi-1.5Ag microstructure was arranged by faceted Bi-rich dendrites surrounded by a eutectic mixture (Bi+Ag). The primary and secondary dendrite arm spacing (λ1 and λ2), the interphase spacing (λ) and the diameter of Ag-rich particles were also measured along the casting length; and experimental growth laws. Relating these microstructural features to the experimental thermal parameters are proposed.

  5. Effect of Substrates Temperatures on the Spreading Behavior of Plasma-Sprayed Ni and Ni-20 wt.% Cr Splats

    NASA Astrophysics Data System (ADS)

    Zhang, Yongang; Hyland, Margaret; Tran, Anh Tuyet; Matthews, Steven

    2016-01-01

    In the formation of plasma-sprayed splats, the spreading behavior of molten droplets is essential for forming desirable lamella with good adhesion to the substrate. To understand the effect of the active element chromium on droplet spreading, pure Ni and Ni-20 wt.% (Ni20Cr) alloyed powders were plasma sprayed on mirror-polished 304 stainless steel substrates heated to different temperatures (below 200 °C). The substrate heating resulted in very little change in the surface roughness. However, there was a measureable change in the surface chemistry of the outermost few nanometers, which became increasingly enriched in Fe at higher temperatures. The splat morphologies were characterized and the transition temperatures were estimated. The results show that the transition from splashed to disk splats was not solely dependent on the temperature of the substrate. In some cases, some splashing still occurred to a measureable extent even at relatively high substrate temperatures, even above temperatures at which adsorbates (moisture) were totally removed from the surface. The splashing behavior could be correlated to a combination of the change in the surface chemistry of the substrate and the presence of active elements in the coating materials.

  6. Micromechanical Behavior of Solid-Solution-Strengthened Mg-1wt.%Al Alloy Investigated by In-Situ Neutron Diffraction

    SciTech Connect

    Lee, Sooyeol; Woo, Wanchuck; Gharghouri, Michael; Yoon, Cheol; An, Ke

    2014-01-01

    In-situ neutron-diffraction experiments were employed to investigate the micromechanical behavior of solid-solution-strengthened Mg-1wt.%Al alloy. Two starting textures were used: 1) as-extruded then solutionized texture, T1, in which the basal poles of most grains are tilted around 70~85 from the extrusion axis, and 2) a reoriented texture, T2, in which the basal poles of most grains are tilted around 10~20 from the extrusion axis. Lattice strains and diffraction peak intensity variations were measured in situ during loading-unloading cycles in uniaxial tension. Twinning activities and stress states for various grain orientations were revealed. The results show that the soft grain orientations, favorably oriented for either extension twinning or basal slip, exhibit the stress relaxation, resulting in the compressive residual strain after unloading. On the other hand, the hard grain orientations, unfavorably oriented for both extension twinning and basal slip, carry more applied load, leading to much higher lattice strains during loading followed by tensile residual strains upon unloading.

  7. Extrusion-formed uranium-2.4 wt. % article with decreased linear thermal expansion and method for making the same

    DOEpatents

    Anderson, Robert C.; Jones, Jack M.; Kollie, Thomas G.

    1982-01-01

    The present invention is directed to the fabrication of an article of uranium-2.4 wt. % niobium alloy in which the linear thermal expansion in the direction transverse to the extrusion direction is less than about 0.98% between 22.degree. C. and 600.degree. C. which corresponds to a value greater than the 1.04% provided by previous extrusion operations over the same temperature range. The article with the improved thermal expansion possesses a yield strength at 0.2% offset of at least 400 MPa, an ultimate tensile strength of 1050 MPa, a compressive yield strength of at least 0.2% offset of at least 675 MPa, and an elongation of at least 25% over 25.4 mm/sec. To provide this article with the improved thermal expansion, the uranium alloy billet is heated to 630.degree. C. and extruded in the alpha phase through a die with a reduction ratio of at least 8.4:1 at a ram speed no greater than 6.8 mm/sec. These critical extrusion parameters provide the article with the desired decrease in the linear thermal expansion while maintaining the selected mechanical properties without encountering crystal disruption in the article.

  8. A 28,000 mol. wt toxin from Bacillus thuringiensis israelensis induces cation transport in rat muscle cultures.

    PubMed

    Cahan, R; Shainberg, A; Pechatnikov, I; Nitzan, Y

    1995-07-01

    The mechanism by which the Bacillus thuringiensis israelensis (Bti) 28,000 mol. wt toxin exerts its effect on mature muscle cultures was examined. The toxin inhibited Na+/K(+)-ATPase activity as revealed by 86Rb influx. A 50% inhibition of Na+/K(+)-ATPase activity was obtained with 0.2 microgram/ml of the toxin. The inhibition was time and dose dependent, and it was reversible with low doses of the toxin (up to 0.2 microgram/ml. A considerable release of 86Rb was obtained by doses greater than 0.2 microgram/ml. The 86Rb release was also time and dose dependent. This effect is probably non-specific, since 45Ca influx is also accelerated by toxin-treated cultures. Pre-incubation of the toxin with phosphotidylserine (PS) antagonized the toxin. It is concluded that the toxin is a hydrophobic protein which interacts with the membrane. In low doses this interaction reduces the activity of the sodium pump and in high doses it causes non-specific permeability of the sarcolemma. PMID:8588218

  9. Method of increasing the phase stability and the compressive yield strength of uranium-1 to 3 wt. % zirconium alloy

    DOEpatents

    Anderson, Robert C.

    1986-01-01

    A uranium-1 to 3 wt. % zirconium alloy characterized by high strength, high ductility and stable microstructure is fabricated by an improved thermal mechanical process. A homogenous ingot of the alloy which has been reduced in thickness of at least 50% in the two-step forging operation, rolled into a plate with a 75% reduction and then heated in vacuum at a temperature of about 750.degree. to 850.degree. C. and then quenched in water is subjected to further thermal-mechanical operation steps to increase the compressive yield strength approximately 30%, stabilize the microstructure, and decrease the variations in mechanical properties throughout the plate is provided. These thermal-mechanical steps are achieved by cold rolling the quenched plate to reduce the thickness thereof about 8 to 12%, aging the cold rolled plate at a first temperature of about 325.degree. to 375.degree. C. for five to six hours and then aging the plate at a higher temperature ranging from 480.degree. to 500.degree. C. for five to six hours prior to cooling the billet to ambient conditions and sizing the billet or plate into articles provides the desired increase in mechanical properties and phase stability throughout the plate.

  10. Preferentially Expressed Antigen of Melanoma (PRAME) and Wilms’ Tumor 1 (WT 1) Genes Expression in Childhood Acute Lymphoblastic Leukemia, Prognostic Role and Correlation with Survival

    PubMed Central

    Khateeb, Engy El; Morgan, Dalia

    2014-01-01

    BACKGROUND: Acute lymphocytic leukemia (ALL) is the most common hematologic malignancy in children. In young children it is also largely curable, with more than 90% of afflicted children achieving long-term remission. PRAME (Preferentially expressed antigen of melanoma) gene belongs to Group 3 class I HLA-restricted widely expressed antigens in which genes encoding widely expressed tumor antigens have been detected in many normal tissues as well as in histologically different types of tumors with no preferential expression on a certain type of cancer. It has been found to be expressed in a variety of cancer cells as leukemia & lymphoma. PRAME monitoring can be useful for detection of minimal residual disease and subsequent relapses particularly those leukemias in which specific tumor markers are unavailable. Wilms’ tumor1 (WT1) gene was identified as a gene that plays an important role in normal kidney development and inactivation of its function was shown to result in the development of Wilms’ tumors in paediatric patients. Disruption of WT1 function has been implicated in the formation of many different tumor types. AIM: to study how PRAME & WT 1 genes expression patterns influence cancer susceptibility & prognosis. PATIENTS & METHODS: 50 patients with denovo childhood acute lymphoblastic leukemia, as well as 50 age and sex matched apparently healthy volunteers were genotyped for PRAME and WT1 genes expression by reverse transcription polymerase chain reaction (RT-PCR). RESULTS: PRAME gene was expressed in 34 of the patients (68%) and WT1 gene was expressed in 26 of the patients (52%). Expression of both genes was significantly higher compared to controls (P < 0.0001). Analysis of relapse free survival among our patients revealed that patients expressing PRAME gene or WT1 gene had better relapse free survival (p value=0.02 and 0.01 respectively). Relapse free survival increased significantly among patients coexpressing PRAME and WT 1(p value =0

  11. CD8 T-cell responses to Wilms tumor gene product WT1 and proteinase 3 in patients with acute myeloid leukemia.

    PubMed

    Scheibenbogen, Carmen; Letsch, Anne; Thiel, Eckhard; Schmittel, Alexander; Mailaender, Volker; Baerwolf, Steffi; Nagorsen, Dirk; Keilholz, Ulrich

    2002-09-15

    Wilms tumor gene product WT1 and proteinase 3 are overexpressed antigens in acute myeloid leukemia (AML), against which cytotoxic T lymphocytes can be elicited in vitro and in murine models. We performed this study to investigate whether WT1- and proteinase 3-specific CD8 T cells spontaneously occur in AML patients. T cells recognizing HLA-A2.1-binding epitopes from WT1 or proteinase 3 could be detected ex vivo in 5 of 15 HLA-A2-positive AML patients by interferon-gamma (IFN-gamma) ELISPOT assay and flow cytometry for intracellular IFN-gamma and in 3 additional patients by flow cytometry only. T cells producing IFN-gamma in response to proteinase 3 were further characterized in one patient by 4-color flow cytometry, identifying them as CD3(+)CD8(+)CD45RA(+) CCR7(-) T cells, resembling cytotoxic effector T cells. In line with this phenotype, most of the WT1- and proteinase-reactive T cells were granzyme B(+). These results provide for the first time evidence for spontaneous T-cell reactivity against defined antigens in AML patients. These data therefore support the immunogenicity of WT1 and proteinase 3 in acute leukemia patients and the potential usefulness of these antigens for leukemia vaccines. PMID:12200377

  12. Compressibility and thermal expansion of hydrous ringwoodite with 2.5(3) wt% H[subscript 2]O

    SciTech Connect

    Ye, Yu; Brown, David A.; Smyth, Joseph R.; Panero, Wendy R.; Jacobsen, Steven D.; Chang, Yun-Yuan; Townsend, Joshua P.; Thomas, Sylvia-Monique; Hauri, Erik H.; Dera, Przemyslaw; Frost, Daniel J.

    2012-04-30

    Ringwoodite ({gamma}-Mg{sub 2}SiO{sub 4}) is the stable polymorph of olivine in the transition zone between 525-660 km depth, and can incorporate weight percent amounts of H{sub 2}O as hydroxyl, with charge compensated mainly by Mg vacancies (Mg{sup 2+} = 2H{sup +}), but also possibly as (Si{sup 4+} = 4H{sup +} and Mg{sup 2+} + 2H{sup +} = Si{sup 4+}). We synthesized pure Mg ringwoodite containing 2.5(3) wt% H{sub 2}O, measured by secondary ion mass spectrometry (SIMS), and determined its compressibility at 300 K by single-crystal and powder X-ray diffraction (XRD), as well as its thermal expansion behavior between 140 and 740 K at room pressure. A third-order Birch-Murnaghan equation of state (BM3 EOS) fits values of the isothermal bulk modulus K{sub T0} = 159(7) GPa and (dK{sub T}/dP){sub P = 0} = K' = 6.7(7) for single-crystal XRD; K{sub T0} = 161(4) GPa and K' = 5.4(6) for powder XRD, with K{sub T0} = 160(2) GPa and K' = 6.2(3) for the combined data sets. At room pressure, hydrous ringwoodite breaks down by an irreversible unit-cell expansion above 586 K, which may be related to dehydration and changes in the disorder mechanisms. Single-crystal intensity data were collected at various temperatures up to 736 K, and show that the cell volume V(cell) has a mean thermal expansion coefficient {alpha}{sub V0} of 40(4) x 10{sup -6}/K (143-736 K), and 29(2) x 10{sup -6}/K (143-586 K before irreversible expansion). V(Mg) have {alpha}{sub 0} values of 41(3) x 10{sup -6}/K (143-736 K), and V(Si) has {alpha}{sub 0} values of 20(3) x 10{sup -6}/K (143-586 K) and 132(4) x 10{sup -6}K (586-736 K). Based on the experimental data and previous work from {sup 29}Si NMR, we propose that during the irreversible expansion, a small amount of H{sup +} cations in Mg sites transfer to Si sites without changing the cubic spinel structure of ringwoodite, and the substituted Si{sup 4+} cations move to the normally vacant octahedral site at (1/2, 1/2, 0). Including new SIMS data on this and

  13. Microstructure and Mechanical Instability of Water-Quenched U-6wt% Nb Alloy Affected by Long-Term Aging

    SciTech Connect

    Hsiung, L; Zhou, J

    2005-12-06

    A combinative approach of microhardness testing, tensile testing, and TEM microstructural analysis was employed to study the microstructure and mechanical instability of a water-quenched U-6wt.% Nb (WQ-U6Nb) alloy subjected to different aging schedules including artificial aging at 200 C, 15-year natural aging at ambient temperatures, and 15-year natural aging followed by accelerative aging at 200 C. The changes in mechanical property during and after the aging processes were examined using microhardness and tensile-testing methods. During the early stages of artificial aging at 200 C, the microhardness of WQ-U6Nb alloy increased, i.e., age hardening, as a result of the development of nanoscale modulation caused by spinodal decomposition. Coarsening of the modulated structure occurred after a prolonged aging at 200 C for 16 hours, and it led to a decrease of microhardness, i.e., age softening. Phase instability was also found to occur in WQ-U6Nb alloy that was subjected to a 15-year natural aging at ambient temperatures. The formation of partially ordered domains resulting from a spinodal modulation with an atomic-scale wavelength rendered the appearance of swirl-shape antiphase domain boundaries (APBs) observed in TEM images. Although it did not cause a significant change in microhardness, 15-year natural aging has dramatically affected the aging mechanisms of the alloy isothermally aged at 200 C. Microhardness values of the NA alloy continuously increased and no age softening was found after isothermal aging at 200 C for 96 hours as a result of the phase decomposition of partially ordered domains into Nb-depleted {alpha} phase and Nb-enriched U{sub 3}Nb ordered phase in the alloy. It is concluded that the long-term natural aging changes the transformation pathway of WQ-U6Nb, and it leads to order-disorder transformation, precipitation hardening, and ductility embrittlement of WQ-U6Nb alloy.

  14. Effects of aging time and temperature of Fe-1wt.%Cu on magnetic Barkhausen noise and FORC

    NASA Astrophysics Data System (ADS)

    Saleh, Muad; Cao, Yue; Edwards, Danny J.; Ramuhalli, Pradeep; Johnson, Bradley R.; McCloy, John S.

    2016-05-01

    Magnetic Barkhausen noise (MBN), hysteresis measurements, first order reversal curves (FORC), Vickers microhardness, and Transmission Electron Microscopy (TEM) analyses were performed on Fe-1wt.%Cu (Fe-Cu) samples isothermally aged at 700°C for 0.5 - 25 hours to obtain samples with different sized Cu precipitates and dislocation structures. Fe-Cu is used to simulate the thermal and irradiation-induced defects in copper-containing nuclear reactor materials such as cooling system pipes and pressure vessel materials. The sample series showed an initial increase followed by a decrease in hardness and coercivity with aging time, which is explained by Cu precipitates formation and growth as observed by TEM measurements. Further, the MBN envelope showed a continuous decrease in its magnitude and the appearance of a second peak with aging. Also, FORC diagrams showed multiple peaks whose intensity and location changed for different aging time. The changes in FORC diagrams are attributed to combined changes of the magnetic behavior due to Cu precipitate characteristics and dislocation structure. A second series of samples aged at 850°C, which is above the solid solution temperature of Fe-Cu, was studied to isolate the effects of dislocations. These samples showed a continuous decrease in MBN amplitude with aging time although the coercivity and hardness did not change significantly. The decrease of MBN amplitude and the appearance of the second MBN envelope peak are attributed to the changes in dislocation density and structure. This study shows that the effect of dislocations on MBN and FORC of Fe-Cu materials can vary significantly and should be considered in interpreting magnetic signatures.

  15. Peculiarities of the volume ratio of α and β phases in the superplastic eutectic Bi-43 wt % Sn Alloy

    NASA Astrophysics Data System (ADS)

    Korshak, V. F.; Mateychenko, P. V.; Shapovalov, Yu. A.

    2014-12-01

    This work deals with the study of the volume ratio of α(Sn) and β(Bi) phases in the as-cast eutectic Bi-43 wt % Sn alloy, as well as in this alloy after casting, followed by compression in a hydraulic press to a degree of deformation of ˜70%, and in this alloy aged for various time intervals. This alloy demonstrates superplastic behavior even at room temperature. The experiments were carried out using scanning electron microscopy and electron-microprobe analysis using a JSM-6390LV scanning electron microscope equipped with an INCA-350 attachment for EDS analysis. Based on the obtained cooling curves, it has been found that, under the selected experimental conditions, the crystallization of the alloy is nonequilibrium. The original phase state of the alloy is characterized by an excessive relative amount of the α(Sn) phase compared to the equilibrium amount even for the eutectic temperature, which is indicative of the quenching of the liquid melt. The phase state of the alloy formed in the course of crystallization is metastable. This is confirmed by the volume ratio of the phases in the specimens subjected to fairly long aging. The data on the earlier discovered effect of the enrichment of open outer surfaces of the specimens in tin in the course of aging are presented. As a cause of the metastability of the phase state of the alloy, internal compression stresses are considered, which arise in the course of crystallization due to an increase in the specific volume of the bismuth phase in going from the liquid to the solid state. The results presented are first reported and are significant for gaining insight into the physical nature of the effect of superplasticity.

  16. Mechanical Deformation Behavior of Sn-Ag-Cu Solders with Minor Addition of 0.05 wt.% Ni

    NASA Astrophysics Data System (ADS)

    Hammad, A. E.; El-Taher, A. M.

    2014-11-01

    The aim of the present work is to develop a comparative evaluation of the microstructural and mechanical deformation behavior of Sn-Ag-Cu (SAC) solders with the minor addition of 0.05 wt.% Ni. Test results showed that, by adding 0.05Ni element into SAC solders, generated mainly small rod-shaped (Cu,Ni)6Sn5 intermetallic compounds (IMCs) inside the β-Sn phase. Moreover, increasing the Ag content and adding Ni could result in the change of the shape and size of the IMC precipitate. Hence, a significant improvement is observed in the mechanical properties of SAC solders with increasing Ag content and Ni addition. On the other hand, the tensile results of Ni-doped SAC solders showed that both the yield stress and ultimate tensile strengths decrease with increasing temperature and with decreasing strain rate. This behavior was attributed to the competing effects of work hardening and dynamic recovery processes. The Sn-2.0Ag-0.5Cu-0.05Ni solder displayed the highest mechanical properties due to the formation of hard (Cu,Ni)6Sn5 IMCs. Based on the obtained stress exponents and activation energies, it is suggested that the dominant deformation mechanism in SAC (205)-, SAC (0505)- and SAC (0505)-0.05Ni solders is pipe diffusion, and lattice self-diffusion in SAC (205)-0.05Ni solder. In view of these results, the Sn-2.0Ag-0.5Cu-0.05Ni alloy is a more reliable solder alloy with improved properties compared with other solder alloys tested in the present work.

  17. The effects of recrystallization texture and grain size on magnetic properties of 6.5 wt% Si electrical steel

    NASA Astrophysics Data System (ADS)

    Pan, Hongjiang; Zhang, Zhihao; Xie, Jianxin

    2016-03-01

    Cold rolled sheets of high silicon electrical steel (Fe-6.5 wt% Si alloy) with thicknesses of 0.2-0.4 mm were fabricated by directional solidification and rolling, and the microstructure, texture and magnetic properties of the sheets annealed at 700-1300 °C for 1 h were investigated. The roles of recrystallization texture and grain size in influencing the magnetic induction and core loss were clarified. All the samples had strong {100} recrystallization texture with volume fraction of 18.3-47.3% and exhibited high magnetic induction and low core loss. For the samples with a thickness of 0.2 mm after annealing at 800-1200 °C, the magnetic induction B8 and the core loss P10/50 reached 1.273-1.378 T and 0.49-0.84 W/kg, respectively. The grain size played a much more important role in the core loss than recrystallization texture. The average grain size to seek minimum core loss P10/50 was 536-615 μm in the high silicon electrical steel sheets with thicknesses of 0.2-0.4 mm, which was larger than 100-200 μm for the electrical steel with common silicon content. The magnetic induction B8 of the samples improved with an enhancement of {100} recrystallization texture, but reduced with an increase of average grain size. The effect of recrystallization texture on the magnetic induction B8 was much greater than that of grain size.

  18. Tensile and compressive creep behavior of extruded Mg–10Gd–3Y–0.5Zr (wt.%) alloy

    SciTech Connect

    Wang, H.; Wang, Q.D.; Boehlert, C.J.; Yin, D.D.; Yuan, J.

    2015-01-15

    The tensile and compressive creep behavior of an extruded Mg–10Gd–3Y–0.5Zr (wt.%) alloy was investigated at temperatures ranging from 200 °C to 300 °C and under stresses ranging from 30 MPa to 120 MPa. There existed an asymmetry in the tensile and compressive creep properties. The minimum creep rate of the alloy was slightly greater in tension than in compression. The measured values of the transient strain and initial creep rate in compression were greater than those in tension. The creep stress exponent was approximately 2.5 at low temperatures (T < 250 °C) and 3.4 at higher temperatures both in tension and in compression. The compression creep activation energy at low temperatures and high temperatures was 83.4 and 184.3 kJ/mol respectively, while one activation energy (184 kJ/mol) represented the tensile–creep behavior over the temperature range examined. Dislocation creep was suggested to be the main mechanism in tensile creep and in the high-temperature regime in compressive creep, while grain boundary sliding was suggested to dominate in the low-temperature regime in compressive creep. Precipitate free zones were observed near grain boundaries perpendicular to the loading direction in tension and parallel to the loading direction in compression. Electron backscattered diffraction analysis revealed that the texture changed slightly during creep. Non-basal slip was suggested to contribute to the deformation after basal slip was introduced. In the tensile–creep ruptured specimens, intergranular cracks were mainly observed at general high-angle boundaries. - Highlights: • Creep behavior of an extruded Mg–RE alloy was characterized by EBSD. • T5 aging treatment enhanced the tension–compression creep asymmetry. • The grains grew slightly during tensile creep, but not for compressive creep. • Precipitate free zones (PFZs) were observed at specific grain boundaries. • Intergranular fracture was dominant and cracks mainly originated at

  19. Binding of single walled carbon nanotube to WT and mutant HIV-1 proteases: analysis of flap dynamics and binding mechanism.

    PubMed

    Meher, Biswa Ranjan; Wang, Yixuan

    2012-09-01

    Most of the currently treated HIV-1 protease (HIV-PR) inhibitors have been prone to suffer from the mutations associated drug resistance. Therefore, it is necessary to search for potent alternatives against the drug resistance. In the current study we have tested the single-walled carbon nanotube (SWCNT) as an inhibitor in wild type (WT) as well as in three primary mutants (I50V(PR), V82A(PR) and I84V(PR)) of the HIV-1-PR through docking the SWCNT in the active site region, and then performed all-atom MD simulations for the complexes. The conformational dynamics of HIV-PR with a 20 ns trajectory reveals that the SWCNT can effectively bind to the HIV-1-PR active site and regulate the flap dynamics such as maintaining the flap-flap closed. To gain an insight into the binding affinity, we also performed the MM-PBSA based binding free energy calculations for the four HIV-PR/SWCNT complexes. It was observed that, although the binding between the SWCNT and the HIV-PR decreases due to the mutations, the SWCNTs bind to the HIV-PRs 3-5 folds stronger than the most potent HIV-1-PR inhibitor, TMC114. Remarkably, the significant interactions with binding energy higher than 1kcal/mol focus on the flap and active regions, which favors closing flap-flap and deactivating the active residues of the HIV-PR. The flap dynamics and binding strength information for HIV-PR and SWCNTs can help design SWCNT-based HIV-1-PR inhibitors. PMID:23142620

  20. Effects of age hardening on magnetic and transport properties of Mg-1.3 wt% Ce alloys

    SciTech Connect

    Yamashita, T.; Cavallaro, P.; Kelly, P.M.; Hisa, M.

    1998-05-22

    Magnesium is the lightest structural metal. It has advantages over many other materials in terms of specific strength, machinability and shock absorption. Improvements in magnesium alloy design and more stringent requirements to reduce fuel consumption and air pollution, have recently focused attention on the use of magnesium alloys for automotive components. Here, a Mg-1.3 wt% Ce alloy has been isothermally heat treated at 423 K and the transport and magnetic properties are investigated. This alloy is known to have distinct age hardening behavior and its age hardened microstructure has been studied in detail. The transport properties depend on the early stage of precipitation which is difficult to define by transmission electron microscopy. The scattering sites of electrons are not identical to precipitates, but consist of strain fields induced by the precipitates, solute atoms, dislocations and vacancies. The resistivity was found to increase initially with aging time and then decrease. The highest resistivity was obtained from a specimen aged for 3.6 ks. This aging time is far less than that of 1,800 ks which gives the maximum hardness. On the other hand, magnetic properties correlate with the later stages of the precipitation. In particular, the imaginary part of the magnetic susceptibility is related to macroscopic formation of precipitates. The imaginary part of the magnetic susceptibility of the alloys seems to be generated by eddy current loss. The imaginary part of the magnetic susceptibility increases monotonically with aging time but it may decrease for extensive aging treatments beyond 3,600 ks.

  1. Microstructural anomalies in hot-isostatic pressed U–10wt.% Mo fuel plates with Zr diffusion barrier

    SciTech Connect

    Park, Y.; Eriksson, N.; Keiser, D. D.; Jue, J.; Rabin, B.; Moore, G.; Sohn, Y. H.

    2015-05-01

    Microstructural anomalies in the co-rolled-and-HIP'ed U–10 wt.% Mo (U10Mo) metallic fuel plate with Zr diffusion barrier assembly were examined as a function of HIP temperature (from 520 to 580 °C) and duration (45, 60, 90, 180 and 345 min) by scanning and transmission electron microscopy. The anomalies observed in this study are carbide/oxide inclusions within the U10Mo fuel alloy, and regions of limited interaction between the U10Mo alloy and Zr barrier, frequently associated with carbide/oxide inclusions. In the U10Mo alloy, the cF8, Fm3m (225) UC phase (a=4.955 Å) and cF12, Fm3m (225) UO2 phase (a=5.467 Å) were observed throughout the U10Mo alloy with an approximate volume percent of 0.5 to 1.8. The volume percent of the UC–UO2 inclusions within the U10Mo alloy did not change as functions of HIP temperature and time. These inclusion phases, located near the surface of the U10Mo alloy, were frequently observed to impede the development of interdiffusion and reaction between the U10Mo alloy and Zr diffusion barrier. The regions of limited interaction between the U10Mo and Zr barrier decreased with an increase in HIP temperature, however no noticeable trend was observed with an increase in HIP duration at constant temperature of 560 °C.

  2. The inflammatory cytokine TNFα cooperates with Ras in elevating metastasis and turns WT-Ras to a tumor-promoting entity in MCF-7 cells

    PubMed Central

    2014-01-01

    Background In the present study we determined the relative contribution of two processes to breast cancer progression: (1) Intrinsic events, such as activation of the Ras pathway and down-regulation of p53; (2) The inflammatory cytokines TNFα and IL-1β, shown in our published studies to be highly expressed in tumors of >80% of breast cancer patients with recurrent disease. Methods Using MCF-7 human breast tumor cells originally expressing WT-Ras and WT-p53, we determined the impact of the above-mentioned elements and cooperativity between them on the expression of CXCL8 (ELISA, qRT-PCR), a member of a “cancer-related chemokine cluster” that we have previously identified. Then, we determined the mechanisms involved (Ras-binding-domain assays, Western blot, luciferase), and tested the impact of Ras + TNFα on angiogenicity (chorioallantoic membrane assays) and on tumor growth at the mammary fat pad of mice and on metastasis, in vivo. Results Using RasG12V that recapitulates multiple stimulations induced by receptor tyrosine kinases, we found that RasG12V alone induced CXCL8 expression at the mRNA and protein levels, whereas down-regulation of p53 did not. TNFα and IL-1β potently induced CXCL8 expression and synergized with RasG12V, together leading to amplified CXCL8 expression. Testing the impact of WT-Ras, which is the common form in breast cancer patients, we found that WT-Ras was not active in promoting CXCL8; however, TNFα has induced the activation of WT-Ras: joining these two elements has led to cooperative induction of CXCL8 expression, via the activation of MEK, NF-κB and AP-1. Importantly, TNFα has led to increased expression of WT-Ras in an active GTP-bound form, with properties similar to those of RasG12V. Jointly, TNFα + Ras activities have given rise to increased angiogenesis and to elevated tumor cell dissemination to lymph nodes. Conclusions TNFα cooperates with Ras in promoting the metastatic phenotype of MCF-7 breast tumor cells

  3. Classification of a frameshift/extended and a stop mutation in WT1 as gain-of-function mutations that activate cell cycle genes and promote Wilms tumour cell proliferation

    PubMed Central

    Busch, Maike; Schwindt, Heinrich; Brandt, Artur; Beier, Manfred; Görldt, Nicole; Romaniuk, Paul; Toska, Eneda; Roberts, Stefan; Royer, Hans-Dieter; Royer-Pokora, Brigitte

    2014-01-01

    The WT1 gene encodes a zinc finger transcription factor important for normal kidney development. WT1 is a suppressor for Wilms tumour development and an oncogene for diverse malignant tumours. We recently established cell lines from primary Wilms tumours with different WT1 mutations. To investigate the function of mutant WT1 proteins, we performed WT1 knockdown experiments in cell lines with a frameshift/extension (p.V432fsX87 = Wilms3) and a stop mutation (p.P362X = Wilms2) of WT1, followed by genome-wide gene expression analysis. We also expressed wild-type and mutant WT1 proteins in human mesenchymal stem cells and established gene expression profiles. A detailed analysis of gene expression data enabled us to classify the WT1 mutations as gain-of-function mutations. The mutant WT1Wilms2 and WT1Wilms3 proteins acquired an ability to modulate the expression of a highly significant number of genes from the G2/M phase of the cell cycle, and WT1 knockdown experiments showed that they are required for Wilms tumour cell proliferation. p53 negatively regulates the activity of a large number of these genes that are also part of a core proliferation cluster in diverse human cancers. Our data strongly suggest that mutant WT1 proteins facilitate expression of these cell cycle genes by antagonizing transcriptional repression mediated by p53. We show that mutant WT1 can physically interact with p53. Together the findings show for the first time that mutant WT1 proteins have a gain-of-function and act as oncogenes for Wilms tumour development by regulating Wilms tumour cell proliferation. PMID:24619359

  4. Spinodal Decomposition and Order-Disorder Transformation in a Water-Quenched U-6wt%Nb Alloy

    SciTech Connect

    Hsiung, L; Zhou, J

    2006-09-12

    A combinative approach of microhardness testing, tensile testing, and TEM microstructural analysis has been employed to study phase stability and aging mechanisms of a water-quenched U-6wt%Nb (WQU6Nb) alloy subjected to different aging schedules that include artificial aging of WQ-U6Nb at 200 C, natural aging of WQ-U6Nb at ambient temperatures for 15 to18 years, and accelerative aging of the naturally aged (NA) alloy at 200 C. During the early stages of artificial aging at 200 C, the microhardness values continuously increase as a result of the development of a fine-scale compositional modulation (wavelength: 3 nm) caused by spinodal decomposition. Coarsening of the modulated structure occurs after prolonged aging of WQ-U6Nb at 200 C for 16 hours, which leads to a decrease of microhardness. Phase instability has also been found to occur in the NA alloy, in which the formation of partially ordered phase domains resulting from an atomic-scale spinodal modulation (wavelength: 0.5 nm) renders the appearance of antiphase domain boundaries (APBs) in TEM images. Although 18-year natural aging does not cause a significant change in hardness, it affects dramatically the aging mechanism of WQ-U6Nb subjected to the accelerative aging at 200 C. The result of microhardness measurement shows that the hardness values continuously increase until after aging for 239 hours, and the total hardness increment is twice in magnitude than that in the case of the artificial aging of water-quenched alloy at 200 C. The anomalous increment of hardness for the accelerative aging of NA alloy can be attributed to the precipitation of an ordered U{sub 3}Nb phase. It is accordingly concluded that the long-term natural aging at ambient temperatures can detour the transformation pathway of WQ U-6Nb alloy; it leads to the order-disorder transformation and precipitation of ordered phase in the alloy.

  5. Full-length U-xPu-10Zr (x = 0, 8, 19 wt.%) fast reactor fuel test in FFTF

    NASA Astrophysics Data System (ADS)

    Porter, D. L.; Tsai, Hanchung

    2012-08-01

    The Integral Fast Reactor-1 (IFR-1) experiment performed in the Fast Flux Test Facility (FFTF) was the only U-Pu-10Zr (Pu-0, 8 and 19 wt.%) metallic fast reactor test with commercial-length (91.4-cm active fuel-column length) conducted to date. With few remaining test reactors, there is little opportunity for performing another test with a long active fuel column. The assembly was irradiated to the goal burnup of 10 at.%. The beginning-of-life (BOL) peak cladding temperature of the hottest pin was 608 °C, cooling to 522 °C at end-of-life (EOL). Selected fuel pins were examined non-destructively using neutron radiography, precision axial gamma scanning, and both laser and spiral contact cladding profilometry. Destructive exams included plenum gas pressure, volume, and gas composition determinations on a number of pins followed by optical metallography, electron probe microanalysis (EPMA), and alpha and beta-gamma autoradiography on a single U-19Pu-10Zr pin. The post-irradiation examinations (PIEs) showed very few differences compared to the short-pin (34.3-cm fuel column) testing performed on fuels of similar composition in Experimental Breeder Reactor-II (EBR-II). The fuel column grew axially slightly less than observed in the short pins, but with the same pattern of decreasing growth with increasing Pu content. There was a difference in the fuel-cladding chemical interaction (FCCI) in that the maximum cladding penetration by interdiffusion with fuel/fission products did not occur at the top of the fuel column where the cladding temperature is highest, as observed in EBR-II tests. Instead, the more exaggerated fission-rate profile of the FFTF pins resulted in a peak FCCI at ˜0.7 X/L axial location along the fuel column. This resulted from a higher production of rare-earth fission products at this location and a higher ΔT between fuel center and cladding than at core center, together providing more rare earths at the cladding and more FCCI. This behavior could

  6. Fiscal year 1997 final report for task plan SR-16WT-31 task B, vitrification of ion exchange material

    SciTech Connect

    Ferrara, D.; Andrews, M.K.; Harbour, J.R.; Fellinger, T.L.; Herman, D.T.; Marshall, K.M.; Workman, P.J.

    1997-09-30

    of CST in Glass (completed 8/97); Demonstrate that Sludge-CST Glass Satisfied PC Specs in WAPS (completed 9/97); Determine Process Parameters of Sludge-CST Glass (completed 8/97); Demonstrate that CST-Only Glass Satisfied PC Specs in WAPS (completed 9/97); Determine Process Parameters of CST-Only Glass (completed 9/97). The results for Task B of Task Plan SR-16WT-31 have been documented in reports that have been included as attachments. The following is a summary of the attachments from the CST vitrification project.

  7. Full-length U-xPu-10Zr (x=0, 8, 19 wt%) Fast Reactor Fuel Test in FFTF

    SciTech Connect

    D. L. Porter; H.C. Tsai

    2012-08-01

    The Integral Fast Reactor-1 (IFR-1) experiment performed in the Fast Flux Test Facility (FFTF) was the only U-Pu-10Zr (Pu-0, 8 and 19 wt%) metallic fast reactor test with commercial-length (91.4 cm active fuel column length) conducted to date. With few remaining test reactors there is little opportunity for performing another test with a long active fuel column. The assembly was irradiated to the goal burnup of 10 at.%. The beginning of life (BOL) peak cladding temperature of the hottest pin was 608?C, cooling to 522?C at end of life (EOL). Selected fuel pins were examined non destructively using neutron radiography, precision axial gamma scanning, and both laser and spiral contact cladding profilometry. Destructive exams included plenum gas pressure, volume, and gas composition determinations on a number of pins followed by optical metallography, electron probe microanalysis (EPMA), and alpha and beta gamma autoradiography on a single U-19Pu-10Zr pin. The post-irradiation examinations (PIEs) showed very few differences compared to the short-pin (34.3 cm fuel column) testing performed on fuels of similar composition in Experimental Breeder Reactor-II (EBR-II). The fuel column grew axially slightly less than observed in the short pins, but with the same pattern of decreasing growth with increasing Pu content. There was a difference in the fuel-cladding chemical interaction (FCCI) in that the maximum cladding penetration by interdiffusion with fuel/fission products did not occur at the top of the fuel column where the cladding temperature is highest, as observed in EBR-II tests. Instead, the more exaggerated fission-rate profile of the FFTF pins resulted in a peak FCCI at ~0.7 X/L axial location along the fuel column. This resulted from a lower production of rare earth fission products higher in the fuel column as well as a much smaller delta-T between fuel center and cladding, and therefore less FCCI, despite the higher cladding temperature. This behavior could

  8. The development of an environmentally friendly protective coating for the depleted uranium-0.75 wt.% titanium alloy

    NASA Astrophysics Data System (ADS)

    Roeper, Donald F.

    This study has been directed towards developing environmentally friendly protective coatings for the depleted uranium (DU)-0.75 wt.% titanium alloy. The surface of the alloy was studied using scanning electron microscopy, energy dispersive spectroscopy and optical microscopy. The acicular martensitic microstructure is revealed after chemical etching. Several impurities have been identified and their prevalence has been found to vary from sample to sample. The electrochemistry of the alloy was studied using open circuit potential measurements and potentiodynamic polarization techniques. The effect of various oxyanions, MoO42-, PO43-, VO43-, MnO4-, SiO 44- and WO42-, on the electrochemical behavior of the DU alloy in nitric acid has been explored and MoO4 2- was chosen for further studies. Surface activation has been examined using fluorine compounds or concentrated nitric acid. Residual fluoride from the activation process was found to interfere with coating formation. Surface activation by nitric acid yields a more robust coating. The corrosion protection of the coatings was evaluated by potentiodynamic polarization testing in quiescent 0.05 M NaCl. The coatings were studied using scanning electron microscopy, energy dispersive spectroscopy and optical microscopy. The acid-activated surface forms a coating that offers corrosion protection after a period of aging. X-ray photoelectron spectroscopy revealed that the protective coating is primarily a polymolybdate bound to a uranyl ion. Rutherford backscattering spectroscopy on the acid-activated coatings shows uranium dioxide migrating to the surface. The coatings on the fluoride-activated samples have been found to contain molybdenum trioxide and a minor component of an Mo(V) oxide. Raman and Infrared spectroscopies have been performed to examine the chemistry during aging. Raman indicates that the coating has an octamolybdate structure and FTIR shows that uranyl hydroxide is present in the as-made coating but no

  9. Semiautomated quantitative image analysis of glomerular immunohistochemistry markers desmin, vimentin, podocin, synaptopodin and WT-1 in acute and chronic rat kidney disease models.

    PubMed

    Funk, J; Ott, V; Herrmann, A; Rapp, W; Raab, S; Riboulet, W; Vandjour, A; Hainaut, E; Benardeau, A; Singer, T; Jacobsen, B

    2016-03-01

    Five different glomerular immunohistochemistry markers were evaluated and compared in four different acute and chronic rat kidney disease models. Progression of glomerular or podocyte damage was shown in the puromycin aminonucleoside nephrosis (PAN) and Zucker fatty/spontaneously hypertensive heart failure F1 hybrid (ZSF1) rat model. Progression and prevention of glomerular damage was demonstrated in the Zucker diabetic fatty (ZDF) and Dahl salt-sensitive (Dahl SS) rat. Immunohistochemistry was performed for desmin, vimentin, podocin, synaptopodin and Wilms tumor protein-1 (WT-1), and evaluation of glomerular immunohistochemistry markers was done by semiautomated quantitative image analysis. We found desmin and WT-1 as the most sensitive markers for podocyte damage in both acute and chronic glomerular damage followed by vimentin, podocin and synaptopodin. We were able to demonstrate that early podocyte damage as shown by increased desmin and vimentin staining together with either a phenotypic podocyte change or podocyte loss (reduced numbers of WT-1-stained podocytes) drives the progression of glomerular damage. This is followed by a reduction in podocyte-specific proteins such as podocin and synaptopodin. Our report describes the different sensitivity of glomerular or podocyte markers and gives future guidance for the selection of the most sensitive markers for efficacy testing of new drugs as well as for the selection of tissue-based toxicity markers for glomerular or podocyte injury. In addition to functional clinical chemistry markers, desmin and WT-1 immunohistochemistry offers reliable and valuable data on the morphologic state of podocytes. PMID:26671788

  10. Abundant Melt Inclusions of Andesite-Dacite Composition (59-68 wt% SiO2) in Basaltic Andesite and Andesite Lavas from the Mexican Arc

    NASA Astrophysics Data System (ADS)

    Pu, X.; Lange, R. A.; Moore, G. M.

    2013-12-01

    The vast majority of published major-element analyses of melt inclusions (MI) fall within three categories: (1) olivine-hosted MI in whole-rock basalts, (2) quartz-hosted MI in whole-rock rhyolites, and (3) plagioclase-hosted MI in phenocryst-rich (25-45%) whole-rock andesites and dacites (typically from large central volcanoes at arcs). Histograms of these published MI analyses as a function of bulk-rock composition (wt% SiO2) show that the olivine-hosted MIs in whole-rock basalts tend to be basaltic in composition, whereas both the quartz-hosted MIs in rhyolites and the plagioclase-hosted MIs in the phenocryst-rich andesites and dacites tend to be rhyolitic (>70 wt% SiO2) in composition. This has led to the observation that there is a paucity of published MI analyses with andesitic-dacitic (59-68 wt% SiO2) composition (e.g., Reubi and Blundy, 2009). This paucity may reflect: (1) a relative rarity of intermediate MI compositions in arc lavas, or (2) a sampling bias. To test sampling bias, the following three lava types were targeted for a systematic study of their phenocryst-hosted MIs: (1) phenocryst-poor to phenocryst-rich basaltic andesites; (2) phenocryst-poor to phenocryst-rich andesites, and (3) phenocryst-poor dacites. These three types of lavas permit a study of how MI composition varies as a function of both whole-rock composition and extent of phenocryst+microphenocryst crystallization. MIs were analyzed in 15 lavas from the Mexican volcanic arc. The most abundant MI mineral host was olivine and plagioclase, respectively, in lavas with 54-59 wt% and 60-69 wt% SiO2 (whole rock). The results show a systematic variation in the composition of MIs as a function of the whole-rock composition. Most MIs in the basaltic andesites range from 59-68 wt% SiO2, showing that intermediate MI compositions are common in this lava type; a few MIs extend down to 55 wt% SiO2. In all samples, there is a wide and continuous range of SiO2 concentration (5-15 wt%) recorded by

  11. Ambient air particulate concentrations and metallic elements principal component analysis at Taichung Harbor (TH) and WuChi Traffic (WT) near Taiwan Strait during 2004-2005.

    PubMed

    Fang, Guor-Cheng; Wu, Yuh-Shen; Wen, Chih-Chung; Huang, Shih-Han; Rau, Jui-Yeh

    2006-09-01

    The purpose of this study is to characterize metallic elements associated with atmospheric particulate matter of total suspended particulate (TSP), fine particle (particle matter with aerodynamical diameter <2.5 microm, PM(2.5)), coarse particle (particle matter with aerodynamical diameter 2.5-10 microm, PM (2.5-10)) at the Taichung Harbor (TH) and WuChi Traffic (WT) sampling site of central Taiwan during March 2004 to February 2005. The result indicated the average total suspended particulate concentration in 1 year was 157.31 and 112.58 microg m(-3) at TH and WT sampling site, respectively. Fine particle (PM(2.5)) size was the dominant species at TH and WT sampling site. In TH sampling site, higher correlation coefficient was observed on total suspended particulates of metallic elements Fe and Zn. And in WT sampling site, higher correlation coefficients displayed on total suspended particulates of metallic elements Fe and Zn, Fe and Mn. Ambient airborne particle principal component analysis of metallic metals was used to identify the possible pollutant sources in this study. At the TH sampling site, 50.81% of the total variance of the data was observed in factor 1. Higher loading of Fe (0.86), Zn (0.79), Pb (0.76), and Mn (0.68) were contributed by traffic emission and the soil source. At the WT sampling site, factor 1 explained 53.74% of the total variance of the data and had high loading for Zn (0.86) and Cu (0.85), which were identified as industrial/traffic emission sources. PMID:16616415

  12. A Comparative Study on the Dry Sliding Wear Behavior of Mild Steel and 6061Al-15wt.%SiCp Composite

    NASA Astrophysics Data System (ADS)

    Banerjee, Arpita; Tungala, Vedavyas; Sala, Kasturi; Biswas, Koushik; Maity, Joydeep

    2015-06-01

    Alumina-steel sliding contacts are often encountered in industrial applications. Aluminum metal matrix composite (AlMMC) is considered as a suitable replacement for ferrous materials. However, Alumina-steel/AlMMC tribological system has not been readily investigated. Accordingly, in this research work, the dry sliding wear characteristic of 6061Al-15wt.%SiCp composite and mild steel against an alumina disk is investigated and compared at three loads (10, 30, and 50 N). In mild steel, the wear mechanism envisages a mild adhesive wear at low load (10 N), while abrasive wear and oxidative wear at higher loads (30 and 50 N). The overall wear rate linearly increased with increasing load. In 6061Al-15wt.%SiCp composite, at all loads, the basic wear mechanism involves abrasive wear with de-bonding of SiC particles and oxidative wear. A non-linear relationship between wear rate and load indicates higher severity of wear loss. Particularly at higher load, the 6061Al-15wt.%SiCp composite suffers from extensive wear loss (26 times higher wear rate at 50 N load) as compared to mild steel. This indicates the unsuitability of using 6061Al-15wt.%SiCp composite as a replacement for mild steel under severe abrasive wear situation. The higher wear severity of 6061Al-15wt.%SiCp composite is attributed to the following: (i) de-bonding of reinforcement (SiC) particles reducing the material strength and subsequent removal of matrix material by micro-chipping mechanism; and (ii) an intense oxidation of 6061Al matrix under frictional heat and subsequent removal of oxide layer.

  13. Comparison of the deformation behaviour of commercially pure titanium and Ti-5Al-2.5Sn(wt.%) at 296 and 728 K

    NASA Astrophysics Data System (ADS)

    Li, H.; Mason, D. E.; Yang, Y.; Bieler, T. R.; Crimp, M. A.; Boehlert, C. J.

    2013-07-01

    The tension and tensile-creep deformation behaviours of a fully-α phase commercially pure (CP) Ti and a near-α Ti-5Al-2.5Sn(wt.%) alloy deformed in situ inside a scanning electron microscope were compared. Tensile tests were performed at 296 and 728 K, while tensile-creep tests were performed at 728 K. The yield stress of CP Ti decreased dramatically with increasing temperature. In contrast, temperature had much smaller effect on the yield stress of Ti-5Al-2.5Sn(wt.%). Electron backscattered diffraction was performed both before and after the deformation, and slip trace analysis was used to determine the active slip and twinning systems, as well as the associated global stress state Schmid factors. In tension tests of CP Ti, prismatic slip was the most likely slip system to be activated when the Schmid factor exceeded 0.4. Prismatic slip was observed over the largest Schmid factor range, indicating that the local stress tensor varies significantly from the global stress state of uniaxial tension. The basal slip activity in Ti-5Al-2.5Sn(wt.%) was observed in a larger faction of grains than in CP Ti. Pyramidal ⟨c + a⟩ slip was more prevalent in CP Ti. Although twinning was an active deformation mode in tension tests of the CP Ti, it was rare in Ti-5Al-2.5Sn(wt.%). During creep, dislocation slip was the primary apparent deformation mechanism in CP Ti, while evidence for dislocation slip was much less apparent in Ti-5Al-2.5Sn(wt.%), where grain boundary sliding was dominant. A robust statistical analysis was carried out to assess the significance of the comparative activity of the different slip systems under the variety of experimental conditions examined.

  14. Low-Temperature Aging Kinetics of a 15-Year Old Water-Quenched U-6wt.% Nb Alloy

    SciTech Connect

    Hsiung, L; Zhou, J

    2007-10-30

    It is well known that U-6wt.% Nb (U-14at.% Nb) alloy has a microstructure containing martensitic phases supersaturated with Nb that can be obtained by rapid quenching the alloy from {gamma} (bcc)-field solid solution to room temperature. The high cooling rate forces the {gamma}-phase solid solution to transform to variants of the low-temperature {alpha} (orthorhombic) phase in which Nb is forced to retain in the supersaturated solid solution. However, the crystal lattice of supersaturated solution formed by rapid quenching is in unstable conditions and is severely distorted since the solubility of Nb in the {alpha} phase at room temperature is nearly zero under an equilibrium condition. Two variant phases, a monoclinic distortion of {alpha} phase that is designated as {alpha}{double_prime} martensite and a tetragonal distortion of {gamma} phase that is designated as {gamma}{sup o} phase, can form in the as-quenched alloy, as shown in Fig. 1. We have learned from our previous TEM studies on the low-temperature aging of a water-quenched U6Nb (WQ-U6Nb) alloy that there are two possible transformation pathways for phase decomposition of the alloy supersaturated with 14 at.% of Nb upon aging at temperatures below 200 C, i.e., (1) supersaturated solid solution {alpha}{double_prime} {yields} spinodal decomposition {yields} {alpha}{sub 1} (Nb-lean) + {alpha}{sub 2} (Nb-rich) at 200 C and (2) supersaturated solid solution {alpha}{double_prime} {yields} spinodal ordering {yields}{alpha}{double_prime}{sub po} (partially ordered phase) {yields} phase decomposition and precipitation {yields} {alpha} (U) + {alpha}{sub o} (U{sub 3}Nb) at ambient temperatures [1]. The mechanisms for the spinodal transformation occurred at 200 C and the spinodal ordering occurred at ambient temperatures are quite similar; both are caused by the composition modulation of Nb except that the wavelength ({lambda} {approx} 3 nm) of modulation for spinodal decomposition is larger than that ({lambda

  15. Comparison of rhodomine-WT and sodium chloride tracer transport in a 4th order arctic river

    NASA Astrophysics Data System (ADS)

    Smull, E. M.; Wlostowski, A. N.; Gooseff, M. N.; Bowden, W. B.; Wollheim, W. M.

    2012-12-01

    Conservative tracers are useful for tracking a parcel of water through a river reach and understanding tracer transport phenomena (i.e. advection, dispersion, and transient storage). Rhodomine- WT (RWT) and sodium chloride (NaCl) are two popular stream tracers. NaCl is considered to be conservative and relatively inexpensive, yet it cannot be detected at very low concentrations. On the other hand, RWT can be detected at very low concentrations (<0.1 ppb), but it is known to photo-degrade and sorb to organic materials. Previous work has compared these tracers with small-scale laboratory analyses and field experiments on small headwater streams. The limitations and advantages to each of these tracers, as applied to large river slug injections, are not clearly understood. This work seeks to answer the following questions: 1) Does RWT improve the tracer window of detection (time of tracer arrival to time of tracer non-detection), compared to NaCl? 2) Are there differences in the late-time tailing behavior of each tracer? More specifically, can we compare RWT and NaCl breakthrough curve tail shapes to understand processes contributing to late time solute transport (transient storage or sorption-desorption)? During the summer of 2012, combined slug additions of RWT and NaCl were injected into a 1.5-kilometer reach on the Kuparuk River, a 4th order tundra river underlain by continuous permafrost located on Alaska's North Slope. Fluorescence and electrical conductivity were continuously logged at the upstream and downstream ends of the reach. Preliminary results show that the window of detection is expanded when using RWT under both high and low flow conditions by 0.2 times the advective transport timescale. Tail shapes are more similar under higher discharge conditions and dissimilar under lower discharge conditions. For example, using an exponential regression model (c(t) = eat) to quantify tail shapes, at Q = 500 l/s the exponential coefficient ratio, aRWT:aNaCl, is 0

  16. Virus growth and antibody responses following respiratory tract infection of ferrets and mice with WT and P/V mutants of the paramyxovirus Simian Virus 5

    PubMed Central

    Capraro, Gerald A.; Johnson, John B.; Kock, Nancy D.; Parks, Griffith D.

    2008-01-01

    P/V gene substitutions convert the non-cytopathic paramyxovirus Simian Virus 5 (SV5), which is a poor inducer of host cell responses in human tissue culture cells, into a mutant (P/V-CPI–) that induces high levels of apoptosis, interferon (IFN)-beta, and proinflammatory cytokines. However, the effect of SV5-P/V gene mutations on virus growth and adaptive immune responses in animals has not been determined. Here, we used two distinct animal model systems to test the hypothesis that SV5-P/V mutants which are more potent activators of innate responses in tissue culture will also elicit higher antiviral antibody responses. In mouse cells, in vitro studies identified a panel of SV5-P/V mutants that ranged in their ability to limit IFN responses. Intranasal infection of mice with these WT and P/V mutant viruses elicited equivalent anti-SV5 IgG responses at all doses tested, and viral titers recovered from the respiratory tract were indistinguishable. In primary cultures of ferret lung fibroblasts, WT rSV5 and P/V-CPI– viruses had phenotypes similar to those established in human cell lines, including differential induction of IFN secretion, IFN signaling and apoptosis. Intranasal infection of ferrets with a low dose of WT rSV5 elicited ~500 fold higher anti-SV5 serum IgG responses compared to the P/V-CPI– mutant, and this correlated with overall higher viral titers for the WT virus in tracheal tissues. There was a dose-dependent increase in antibody response to infection of ferrets with P/V-CPI–, but not with WT rSV5. Together our data indicate that WT rSV5 and P/V mutants can elicit distinct innate and adaptive immunity phenotypes in the ferret animal model system, but not in the mouse system. We present a model for the effect of P/V gene substitutions on SV5 growth and immune responses in vivo. PMID:18456301

  17. The cell-permeable Aβ1-6A2VTAT(D) peptide reverts synaptopathy induced by Aβ1-42wt.

    PubMed

    Cimini, Sara; Sclip, Alessandra; Mancini, Simona; Colombo, Laura; Messa, Massimo; Cagnotto, Alfredo; Di Fede, Giuseppe; Tagliavini, Fabrizio; Salmona, Mario; Borsello, Tiziana

    2016-05-01

    Alzheimer disease (AD) is the most prevalent form of dementia. Loss of hippocampal synapses is the first neurodegenerative event in AD. Synaptic loss has been associated with the accumulation in the brain parenchyma of soluble oligomeric forms of amyloid β peptide (Aβ1-42wt). Clinical observations have shown that a mutation in the APP protein (A673V) causes an early onset AD-type dementia in homozygous carriers while heterozygous carriers are unaffected. This mutation leads to the formation of mutated Aβ peptides (Aβ1-42A2V) in homozygous patients, while in heterozygous subjects both Aβ1-42wt and Aβ1-42A2V are present. To better understand the impact of the A673V mutation in AD, we analyzed the synaptotoxic effect of oligomers formed by aggregation of different Aβ peptides (Aβ1-42wt or Aβ1-42A2V) and the combination of the two Aβ1-42MIX (Aβ1-42wt and Aβ1-42A2V) in an in vitro model of synaptic injury. We showed that Aβ1-42A2V oligomers are more toxic than Aβ1-42wt oligomers in hippocampal neurons, confirming the results previously obtained in cell lines. Furthermore, we reported that oligomers obtained by the combination of both wild type and mutated peptides (Aβ1-42MIX) did not exert synaptic toxicity. We concluded that the combination of Aβ1-42wt and Aβ1-42A2V peptides hinders the toxicity of Aβ1-42A2V and counteracts the manifestation of synaptopathy in vitro. Finally we took advantage of this finding to generate a cell-permeable peptide for clinical application, by fusing the first six residues of the Aβ1-42A2V to the TAT cargo sequence (Aβ1-6A2VTAT(D)). Noteworthy, the treatment with Aβ1-6A2VTAT(D) confers neuroprotection against both in vitro and in vivo synaptopathy models. Therefore Aβ1-6A2VTAT(D) may represent an innovative therapeutic tool to prevent synaptic degeneration in AD. PMID:26721320

  18. WT1 Promotes Cell Proliferation in Non-Small Cell Lung Cancer Cell Lines through Up-Regulating Cyclin D1 and p-pRb In Vitro and In Vivo

    PubMed Central

    Xia, Yang; Zhong, Zhaopeng; Liu, Xiang; Xu, Jing; Cui, Fei; Chen, Bin; Røe, Oluf Dimitri; Li, Aihong; Chen, Yijiang

    2013-01-01

    The Wilms’ tumor suppressor gene (WT1) has been identified as an oncogene in many malignant diseases such as leukaemia, breast cancer, mesothelioma and lung cancer. However, the role of WT1 in non-small-cell lung cancer (NSCLC) carcinogenesis remains unclear. In this study, we compared WT1 mRNA levels in NSCLC tissues with paired corresponding adjacent tissues and identified significantly higher expression in NSCLC specimens. Cell proliferation of three NSCLC cell lines positively correlated with WT1 expression; moreover, these associations were identified in both cell lines and a xenograft mouse model. Furthermore, we demonstrated that up-regulation of Cyclin D1 and the phosphorylated retinoblastoma protein (p-pRb) was mechanistically related to WT1 accelerating cells to S-phase. In conclusion, our findings demonstrated that WT1 is an oncogene and promotes NSCLC cell proliferation by up-regulating Cyclin D1 and p-pRb expression. PMID:23936312

  19. 200 MeV Ag15+ ion beam irradiation effects on spray deposited 5 wt% `Li' doped V2O5 thin film

    NASA Astrophysics Data System (ADS)

    Kovendhan, M.; Joseph, D. Paul; Manimuthu, P.; Sendilkumar, A.; Asokan, K.; Venkateswaran, C.; Mohan, R.

    2016-05-01

    Lithium 5 wt% doped V2O5 thin film was deposited onto ITO substrate by spray pyrolysis technique. The substrate temperature was kept at 450 °C. 200 MeV Ag15+ ion beams at a fluence of 5×1012 ions/cm2 was irradiated on 5 wt% `Li' doped V2O5 film of thickness 1367 nm. The XRD pattern confirms that the pristine film is non stoichiometry with orthorhombic structure and upon irradiation the crystallinity decreased and an obvious textured growth along (020) plane is induced. Raman peak observed at 917 cm-1 is due to oxygen deficiency. Upon irradiation, the optical transparency and band gap of the film decreased. Electrical transport property study shows that the resistivity increased by one order for the irradiated film.

  20. Microstructure Investigation of Directionally Solidified NiAl-Cr(Mo)- xDy ( x = 0, 0.1 wt.%) Hypereutectic Alloys at Different Withdrawal Rates

    NASA Astrophysics Data System (ADS)

    Wang, Lei; Shen, Jun; Shang, Zhao; Zhang, Jian-Fei; Du, Yu-Jun; Fu, Heng-Zhi

    2013-11-01

    The microstructures of directionally solidified Ni-31Al-32Cr-6Mo (at.%)- xDy ( x = 0, 0.1 wt.%) hypereutectic alloys were studied at different withdrawal rates. The results show that the microstructure changes from the planar eutectic to the cellular eutectic and the volume fraction of the primary Cr(Mo) dendrites decreases for the Dy-free alloy with the withdrawal rate varying from 6 μm/s to 30 μm/s. The addition of 0.1 wt.% Dy promotes the planar-to-cellular transition. Moreover, the white Dy-containing phase does not form in the alloy for the planar interface growth (6 μm/s), but it can occur in the boundary of eutectic cells for the cellular interface growth (30 μm/s). A sketchy model of the planar and cellular growth is supposed to interpret it.