Model Analysis of Time Reversal Symmetry Test in the Caltech Fe-57 Gamma-Transition Experiment

The CALTECH gamma-transition experiment testing time reversal symmetry via the E2/M1 mulipole mixing ratio of the 122 keV gamma-line in Fe-57 has already been performed in 1977. Extending an earlier analysis in terms of an effective one-body potential, this experiment is now analyzed in terms of effective one boson exchange T-odd P-even nucleon nucleon potentials. Within the model space considered for the Fe-57 nucleus no contribution from isovector rho-type exchange is possible. The bound on the coupling strength phi_A from effective short range axial-vector type exchange induced by the experimental bound on sin(eta) leads to phi_A < 10^{-2}.Comment: 5 pages, RevTex 3.

Exploring the Structure and Bonding of the Zintl Compounds: A14GaAs11 (A = Ca, Sr)

SrnGaAsn has been synthesized by reacting the stoichiometric combination of the elements in a sealed niobium tube, seeded in a quartz ampule under purified argon at 1200 °C for 24 hours. Single crystal X-ray diffraction data (130 K, a = 16.498(8) A, c = 22.132(12) A) were refined. The compound is isostructural to Cai4AlSbn (tetragonal, Z4i/acd (#142, origin choice 2), Z = 8, J?w = 4.4% for 770 independent reflections). The structure consists of discrete GaAs4 tetrahedra, As3 linear units and isolated As euiions and Sr cations. Optical absorption data is consistent with this new compound being a semiconductor with an optical band gap of approximately 1.44 eV, veiy similar to that of GaAs (1.42 eV). The structure and properties are discussed and compared with CauGaAsn and GaAs

Colored anodizing of titanium with pyroligneous solutions of black wattle

In many places, charcoal production, using Australian Blackwood, is still a rudimentary process, generating huge environmental impact, due to the release of pyrolysis smoke into the atmosphere. Both the society and governmental agencies is pushing the factories to condense the smoke, generating byproduct known as pyroligneous liquor. Although it's largely used for agricultural purpose, as a fertilizer and phytosanitizer, its chemical composition presents hydrogen and oxygen rich compounds, making it a potential electrolyte in the surface treatment industry, especially for anodization. Organic alternatives are being used to replace these electrolytes to make the anodizing process cleaner. Then, for the first time, Australian Blackwood pyroligneous liquor was used as an anodizing electrolyte for titanium TICP-G2, to obtain oxides for protection and coloring of the metal. For such, suitable parameters to execute the process were determined (dilution, current density, temperature, agitation, pH, conductivity) and an analysis of the transient potential over time was made. The anodized surfaces were characterized using top view Scan Electronic Microscopy (SEM) and Grazing Incidence X-ray Diffraction (GIXRD).  Based on the results presented, it can be concluded that the best parameters to anodize the titanium were obtained with 50% pyroligneous liquor diluted in water, obtaining colored surfaces and promoting the formation of oxide crystallites clusters mainly in longer  process times (3600s).  Keywords: Pyroligneous liquor, Titanium, Anodizing