Sharpening the predictions of big-bang nucleosynthesis

Motivated by the recent measurement of the primeval abundance of deuterium, we re-examine the nuclear inputs to big-bang nucleosynthesis (BBN). Using Monte-Carlo realization of the nuclear cross-section data to directly estimate the theoretical uncertainties for the yields of D, 3-He and 7-Li, we show that previous estimates were a factor of 2 too large. We sharpen the BBN determination of the baryon density based upon deuterium, rho_B = (3.6 +/- 0.4) * 10^{-31} g/cm^3 (Omega_B h^2 = 0.019 +/- 0.0024), which leads to a predicted 4-He abundance, Y_P = 0.246 +/- 0.0014 and a stringent limit to the equivalent number of light neutrino species: N_nu < 3.20 (all at 95% cl). The predicted 7-Li abundance, 7-Li/H = (3.5 + 1.1 - 0.9) * 10^{-10}, is higher than that observed in pop II stars, (1.7 +/- 0.3) * 10^{-10} (both, 95% cl). We identify key reactions and the energies where further work is needed.Comment: 5 pages, 4 figures (epsfig), REVTeX; submitted to Phys. Rev. Let

Heat dissipation of high rate Li-SOCl sub 2 primary cells

The heat dissipation problem occurring in the lithium thionyl chloride cells discharged at relatively high rates under normal discharge conditions is examined. Four heat flow paths were identified, and the thermal resistances of the relating cell components along each flow path were accordingly calculated. From the thermal resistance network analysis, it was demonstrated that about 90 percent of the total heat produced within the cell should be dissipated along the radial direction in a spirally wound cell. In addition, the threshold value of the heat generation rate at which cell internal temperature could be maintained below 100 C, was calculated from total thermal resistance and found to be 2.9 W. However, these calculations were made only at the cell components' level, and the transient nature of the heat accumulation and dissipation was not considered. A simple transient model based on the lumped-heat-capacity concept was developed to predict the time-dependent cell temperature at different discharge rates. The overall objective was to examine the influence of cell design variable from the heat removal point of view under normal discharge conditions and to make recommendations to build more efficient lithium cells

Corrigendum to "Effects of organic composition on mesophilic anaerobic digestion of food waste" [Bioresour. Technol. 244 (2017) 213-224]

Yangyang Li, Yiying Jin, Aiduan Borrion, Hailong Li, Jinhui Li (2017) Effects of organic composition on mesophilic anaerobic digestion of food waste, Bioresource Technology, Volume 244, Part 1, November 2017, Pages 213-224 (https://doi.org/10.1016/j.biortech.2017.07.006

Discovery of Li2(Pd,Pt)3B superconductors

Critical temperature Tc of the Li2(Pd1-xPtx)3B was reported to be 7-8K for x=0 and 2.2-2.8K for x=1. In this article we present our preliminary results on behavior of magnetization-temperature curves with starting composition of Pd-B precursor, y-Li concentration in LiyPd3B and post-annealing of the Pd-end compound. Results suggest that to maximize Tc ratio Pd:B should be close to 3:1, while y-Li has to be optimum. The lowest Tc for LiyPd3B was 4.4-4.6K, while post-annealings at 560 deg. C allowed enhancement of Tc up to 8.2-8.4K. Compositions Li2Z3B with Z=Ni, Ru, Rh, Re, Ag are not superconducting down to 1.8K. Exception is composition with Re showing superconductivity due to Re3B compound. All samples were prepared by arc melting.Comment: 6 pages, 5 figs. presented at M2S, 200

Superconductivity in metal rich Li-Pd-B ternary Boride

8K superconductivity was observed in the metal rich Li-Pd-B ternary system. Structural, microstructural, electrical and magnetic investigations for various compositions proved that Li2Pd3B compound, which has a cubic structure composed of distorted Pd6B octahedrons, is responsible for the superconductivity. This is the first observation of superconductivity in metal rich ternary borides containing alkaline metal and Pd as a late transition metal. The compound prepared by arc melting has high density, is stable in the air and has an upper critical field, Hc2(0), of 6T.Comment: 4 pages, 5 figur