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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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11 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2012

Nuclear Data Sheets for A = 92

Nuclear structure and decay data pertaining to all nuclides with mass number A = 92 (As, Se, Br, Kr, Rb, Sr, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd) have been compiled and evaluated, and incorporated into the ENSDF data file. All literature available by 15 September 2012 has been considered. This evaluation supersedes the previous publication for this mass chain (Coral M. Baglin, Nuclear Data Sheets 91, 423 (2000) (November 2000 cutoff date)), and subsequent unpublished reevaluations by C.M. Baglin for {sup 92}Kr (January 2004 literature cut-off) and {sup 92}Sr (August 2003 literature cut-off).

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2017

Excitation Function Calculations of Neutron-Induced Reactions of Some Zirconium Target Isotopes

Nuclear structures with high performance materials will be critical for the success of future fusion energy. Zirconium alloys are extensively used for nuclear reactor core materials as fuel cladding and guide tubes due to excellent radiation and corrosion resistant properties. In this paper, the excitation functions of {sup 90}Zr(n,2n){sup 89}Zr, {sup 90}Zr(n,α){sup 87}Sr, {sup 91}Zr(n,p){sup 91}Y and {sup 92}Zr(n,p){sup 92}Y nuclear reactions were calculated for energies up to 25 MeV. Besides, ALICE/ASH and TALYS 1.6 codes were used for the cross section calculations. The obtained calculations were compared with the experimental data in the literature.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2013

Elastic alpha scattering experiments and the alpha-nucleus optical potential at low energies

High precision angular distribution data of (α,α) elastic scattering are presented for the nuclei {sup 89}Y, {sup 92}Mo, {sup 106,110,116}Cd, {sup 112,124}Sn, and {sup 144}Sm at energies around the Coulomb barrier. Such data with small experimental uncertainties over the full angular range (20–170°) are the indispensable prerequisite for the extraction of local optical potentials and for the determination of the total reaction cross section σ{sub reac}. A systematic fitting procedure was applied to the experimental scattering data presented to obtain comprehensive local potential parameter sets that are composed of a real folding potential and an imaginary potential of Woods–Saxon surface type. The potential parameters obtained were used in turn to construct a new systematic α-nucleus potential with very few parameters. Although this new potential cannot reproduce the angular distributions with the same small deviations as the local potential, the new potential is able to predict the total reaction cross sections for all cases under study.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2017

Zirconium and Yttrium (p, d) Surrogate Nuclear Reactions: Measurement and determination of gamma-ray probabilities: Experimental Physics Report

This technical report documents the surrogate reaction method and experimental results used to determine the desired neutron induced cross sections of 87 Y(n,g) and the known 90 Zr(n,g) cross section. This experiment was performed at the STARLiTeR apparatus located at Texas A&M Cyclotron Institute using the K150 Cyclotron which produced a 28.56 MeV proton beam. The proton beam impinged on Y and Zr targets to produce the nuclear reactions 89 Y(p,d) 88 Y and 92 Zr(p,d) 91 Zr. Both particle singles data and particle-gamma ray coincident data were measured during the experiment. This data was used to determine the γ-ray probability as a function of energy for these reactions. The results for the γ-ray probabilities as a function of energy for both these nuclei are documented here. For completeness, extensive tabulated and graphical results are provided in the appendices.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2019

Single-Grain Bulk YBa{sub 2}Cu{sub 3}O{sub y} Superconductor Grown in Shorter Duration by IG Process

The top-seeded infiltration growth (IG) process is considered to be an attractive, well-established route compared to melt growth (MG) process due to its successful ability to resolve observed problems in MG process such as pores, shrinkage, and an ununiformed Y{sub 2}BaCuO{sub 5} (Y-211) secondary phase particle dispersion in Y-123 matrix. This is among the first accounts of superconductivity where a large grain YBa{sub 2}Cu{sub 3}O{sub y} (Y-123) was produced by IG process. Further, by utilizing homemade Y-123 and Y-211, we had prepared YBa{sub 2}Cu{sub 3}O{sub y} samples via Y-123 + liquid (1:1) as a liquid source and had further characterized by utilizing the scanning electron microscopy (SEM), superconducting transition temperature (T{sub c}), and critical current density (J{sub c}) at 77 K. Here, we provide temperature dependence of magnetization measurements that indicated a sharp superconducting transition with T{sub c} (onset) around 92 K. In addition, the critical current density was calculated on the basis of Bean’s model and resulted as 30,000 A/cm{sup 2} at 77 K (self-field), H//c-axis. Trapped field experiments had lucidly indicated that single-grain nature with maximum-trapped field of 0.3 T at 77 K and 1 mm above sample surface even samples are produced shorter duration, i.e., 50 h.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2019

Fabrication and Characterization of Aligned YBa{sub 2}Cu{sub 3}O{sub 7 − δ} Superconductor Electrospun Nanofibers and Twisted Yarn Based on PVA

YBa{sub 2}Cu{sub 3}O{sub 7 − δ} (YBCO) superconducting twisted yarns from electrospun aligned nanofibers are produced with a critical transition temperature of T{sub c} = 92 K. A solution of PVA and Y–Ba–Cu acetates are used as a precursor in the electrospinning to prepare aligned nanofibers and twisted yarns. The aligned nanofibers and twisted yarns are then pyrolysed to remove PVA and sintered to obtain a superconducting phase. Finally, before and after sintering, the aligned nanofibers and twisted yarns are studied by SEM, XRD, and AC magnetic susceptibility techniques. Results are presented in this paper.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2017

Effect of CdTe Addition on the Electrical Properties and AC Susceptibility of YBa{sub 2}Cu{sub 3}O{sub 7−δ} Superconductor

The effect of CdTe addition on YBa{sub 2}Cu{sub 3}O{sub 7−δ}(CdTe){sub x} (x = 0–0.10) has been studied. XRD patterns showed the presence of impurities including CdTe for x ≥ 0.05 wt%. The resistance versus temperature curves showed metallic behavior for all samples. The onset temperature T{sub c onset} for all samples is between 90 and 92 K. The superconducting transition width, ΔT{sub c} = 4 K for all samples except for x = 0.1 wt% where ΔT{sub c} = 6 K. The superconducting transition determined by AC susceptibility measurement also showed little change in T{sub cχ{sup ′}} (between 89 and 92 K). However, the peak temperature T{sub p} of the imaginary part of the susceptibility χ″, showed a drastic decrease for samples with x > 0.05 wt%. This indicated that the superconducting grains were strongly decoupled for x > 0.05 wt% due to the impurities as observed in the XRD pattern. The intergrain critical current density, J{sub c} at T{sub p} for the x = 0 sample is J{sub c} (82 K) = 17 A cm{sup −2}. These results can be useful in the fabrication of semiconductor/YBCO superconductor hybrid systems.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2018

AC Susceptibility and Superconducting Properties of Graphene Added YBa{sub 2}Cu{sub 3}O{sub 7−d}

The effect of graphene (G) addition on YBa{sub 2}Cu{sub 3}O{sub 7−δ}(G){sub x} (x = 0 − 0.03 wt%) has been studied using the X-ray diffraction method, scanning electron microscopy, electrical resistance versus temperature, transport critical current density J{sub c}, and AC susceptibility measurements. XRD patterns showed single-phase YBa{sub 2}Cu{sub 3}O{sub 7−δ} (YBCO) for all samples. SEM micrographs showed filling of the voids between YBa{sub 2}Cu{sub 3}O{sub 7−δ} grains as graphene was added. The temperature-dependent electrical resistance curves showed metallic normal state behavior and onset transition temperature T{sub conset} between 90 and 92 K for all samples. AC susceptibility measurement showed transition temperature T{sub cχ{sup ′}} between 90 and 93 K. T{sub cχ{sup ′}} was maintained or improved slightly as graphene was added. The x = 0.001 wt% showed the highest J{sub c}, i.e., 2750 A cm{sup −2} at 77 K and 5570 mA cm{sup −2} at 30 K which was 13 and 40 times higher than that of the non-added YBCO, respectively. The peak temperature T{sub p} of the imaginary part of the susceptibility χ{sup ″} was around 78–82 K for all samples indicating grain coupling was not weakened as graphene was added.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2019

Calcium-Substituted Y{sub 3}Ba{sub 5}Cu{sub 8}O{sub 18} Ceramics Synthesized via Thermal Treatment Method: Structural and Superconducting Properties

In this work, Y{sub 3}(Ba{sub 1−x}Ca{sub x}){sub 5}Cu{sub 8}O{sub 18} compounds with x = 0.00, 0.01, 0.02, 0.03 and 0.05 were synthesized by thermal treatment of aqueous solution of metal nitrates and polyvinylpyrrolidone (PVP). The effects of Ca substitution on the crystal structure, electrical resistance and the microstructure of samples were investigated using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), four-point probe measurement and AC susceptibility. FESEM analysis showed that there was an increase in the grain size and compactness. The zero-resistance critical temperature decreased from 92 K for the pure sample to 83 K for sample x = 0.05. From AC susceptibility result, the intra- and inter-granular loss peaks shifted toward lower temperature and become wider and broader with the increase of Ca substitution due to the weakening of grain coupling. On the other hand, the inter-granular critical current density (J{sub cm}) was found to increase with Ca substitution and has the highest value J{sub cm} = 35 A cm{sup − 2} at x = 0.05, indicating that the Ca substitution was associated with the formation of pinning centres in the Y-358 matrix.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2015

Atomistic study on the site preference and lattice vibration of Gd{sub 3−x}Y{sub x}Co{sub 29}T{sub 4}B{sub 10} (T=Al and Ge)

The effects of the Y substitution for Gd on the structural stability and the site preference of intermetallics Gd{sub 3−x}Y{sub x}Co{sub 29}T{sub 4}B{sub 10} (T=Al and Ge) are studied by using a series of interatomic pair potentials. The calculated results show Y can stabilize Gd{sub 3−x}Y{sub x}Co{sub 29}T{sub 4}B{sub 10} with the tetragonal structure, and Y substitute for Gd with a strong preference for the 2b sites. The calculated lattice parameters are in good agreement with the experimental data. Furthermore, the total and partial phonon densities of states are evaluated for the Gd{sub 3−x}Y{sub x}Co{sub 29}T{sub 4}B{sub 10} compounds with the tetragonal structure. A qualitative analysis is carried out with the relevant potentials for the vibrational modes, which makes it possible to predict some properties related to lattice vibration. - Graphical abstract: The lattice cell of Gd{sub 3}Co{sub 29}T{sub 4}B{sub 10} consists of 92 atoms, or two Gd{sub 3}Co{sub 29}T{sub 4}B{sub 10} formula units, with fourteen distinct kinds of site. Rare-earth atoms occupy 2b and 4d sites, Co atoms occupy the Co1(2c), Co2(8i1), Co3(8i2), Co4(8i3), Co5(8j1), Co6(8j2) and Co7(16k), T atoms occupy the T(8i) sites, and B atoms occupy the B1(2c1), B2(2c2), B3(8i) and B4(8j) sites. - Highlights: • The application of the pair potentials obtained from lattice-inversion method. • The lattice vibrations for Gd{sub 3−x}Y{sub x}Co{sub 29}T{sub 4}B{sub 10} (T=Ge and Al) are first evaluated. • The Y atoms should prefer the 2b site of Gd{sub 3−x}Y{sub x}Co{sub 29}T{sub 4}B{sub 10} compounds. • The total and partial phonon densities of states are evaluated for the Gd{sub 3−x}Y{sub x}Co{sub 29}T{sub 4}B{sub 10} compounds with the tetragonal structure. • A qualitative analysis is carried out with the relevant potentials for the vibrational modes.

36 MATERIALS SCIENCE↗
DOE OSTI2019

Magnetoresistance Hysteresis Evolution in the Granular Y–Ba–Cu–O High-Temperature Superconductor in a Wide Temperature Range

The temperature evolution of the magnetoresistance hysteresis in the granular YBa{sub 2}Cu{sub 3}O{sub 7-δ} high-temperature (T{sub C} ≈ 92 K) superconductor has been investigated. The measurements have been performed in the high-temperature region (78–90 K) and at the liquid helium temperature (4.2 K). The results obtained have been analyzed using the developed model of the behavior of transport properties of a granular high-temperature superconductor in an external magnetic field. Within the discussed model, the dissipation of the grain boundary subsystem is determined by the intergrain spacing-averaged effective field B{sub eff}, which is a superposition of external field H and the field induced by the magnetic moments of superconducting grains. Such a consideration yields the expression B{sub eff}(H) = H − 4πM(H) α for the effective field in the intergrain medium, where M(H) is the experimental hysteretic dependence of magnetization and α is the parameter of magnetic flux crowding in the intergrain medium. Here, the magnetoresistance is assumed to be proportional to the absolute value of the effective field: R(H) ~ |B{sub eff}(H)|. Analysis of the experimental R(H) and M(H) dependences obtained under the same conditions for the investigated high-temperature superconductor sample showed that in the high-temperature region this parameter is α ≈ 25. At the low temperature (4.2 K), we may state that the degree of flux crowding increases and the estimated α value is ~ 50. The estimates made are indicative of the strong effect of flux compression in the intergrain medium on the magnetotransport properties of the investigated granular high-temperature superconductor system. Possible reasons for a discrepancy between the developed model concepts and experimentally observed low-temperature R(H) hysteresis are analyzed.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗