Thermal behaviour and firing characteristics of Zr/KClO4 primer mixture containing CuO

The effect of CuO on the thermal behaviour of Zr/KClO₄ primer mixtures was studied by thermoanalytical techniques, and the Bruceton method and its related calculation. It was found that the CuO catalytically promoted the decomposition of Zr/KClO₄ primer mixtures and shifted the exothermic peak of DSC curves to lower temperatures. In addition, the Zr/KClO₄ primer mixture containing CuO had a significant effect on the firing characteristics of electro-explosive devices.     

Tritium content as indicator of environmental character on Taiwan Island

Environmental characters have been established by tritium contents in well water, coastal seawater and reservoir water collected from various places around Taiwan island. Tritium concentrations of samples were detected by a liquid scintillation analyzer TRI-CARB-LSC 2550 TR mode, with a low level standard quench curve. After samples were concentrated by electrolysis, tritium concentration was detected in optimum conditions of LLLSA. An electrolytic enrichment technique was also developed with a eurrent density of 100 mA/cm² and 0.4–0.6% (Na₂O₂) electrolyte in concentrated samples. Data observed show a lower tritium concentration for coastal seawater than for wells in the same area. The tritium concentration ratio of well and coastal seawater on the western side of Taiwan is 4.000 and on the eastern side 5.801. Tritium content of reservoir water is related to the logarithm of effective volume capacity.     

The Thermal Properties and Firing Characteristics of Zr/KClO4 Priming Compositions Containing Graphite,Fe2O3 and Al2O3 additives

Thermal decomposition of Zr/KClO₄ priming compositions containing different concentration of additives, such as graphite, Fe₂O₃ and Al₂O₃ have been studied by DSC/TG techniques. The firing characteristics of these primer mixtures have also been examined by Bruceton test and by adiabatic calorimeter. The results of these experiments suggest that strong interaction has been occurred between KClO₄ and Fe₂O₃ in the solid state. This revised version was published online in July 2006 with corrections to the Cover Date.     

Accumulation of Dieldrin,Heptachlor and DDT on Tea Leaves

Tea leaves grown in a field that had been treated in the nearby top soil with 75% DDT 1kg per hectare, 50% Dieldrin 10kg per hectare, or 2.5% Heptachlor 50kg per hectare were analyzed separately. Dieldrin residues accumulated to a maximum of over 0.20ppm. DDT and both Heptachlor and its metabolite, Heptachlor Epoxide, were much lower than that of Dieldrin, with only a few samples detectable.     

Kinetic study of Y, Ba, Cu oxalates and coprecipitated Y-Ba-Cu oxalate

The kinetics of the decomposition of Y, Ba and Cu oxalates and coprecipitanted Y-Ba-Cu oxalate was investigated under a nitrogen atmosphere on the basis of dynamic thermogravimetric data, the average activation energies of the decomposition of Y, Ba and Cu oxalates were obtained from the slopes of the T. Ozawa plot. The average activation energies for the dehydration of these oxalate and coprecipitated Y-Ba-Cu oxalate were also evaluated from the thermogravimetric curves.     

Devitrification Behavior of Calcium Phosphate Glasses Containing Al2O3 and SiO2 Additives

The effects of Al₂O₃ and SiO₂ additives on the crystallization of calcium phosphate glasses were studied. When the Al₂O₃ content was higher than 7 mol%, surface devitrification occurred in the glasses. However, for glasses with Al₂O₃ contents higher than 10 mol%, bulk devitrification predominanted. For the glasses with SiO₂, a surface devitrification mechanism predominanted. Non-isothermal DTA techniques were applied in order to establish the devitrification mechanism, and the kinetic parameters of crystal growth were obtained. The parameter m depends on the mechanism and morphology of devitrification of calcium phosphate, glass containing SiO₂ as additive, the values of m being lower than 1.2. These results indicate that the devitrification is controlled by the reaction at the glass-crystal interface, or occurs from surface nuclei. This revised version was published online in July 2006 with corrections to the Cover Date.     

A Study on the Thermal Behaviour of Solder Glass

Vitreous solder glasses, such as Mansol #40 and FEG-2002, are commercialized solder glasses, which are compression sealing glasses that can be used to solder materials with expansions between 55-68⊙10^-7°C^-1, such as Al₂O₃. In order to understand and tailor the thermal behaviour of solder glasses, cylindrical-like glasses were first carefully ground with a stainless steel mortar and pestle. Initially, no exothermic or endothermic data were obtained from the DTA/DSC curves except those relating to melting. However, exothermic peaks appeared after the glass samples were re-melted. In this work, kinetic parameters such as the activation energy, and the morphology of the devitrification mechanisms for two kinds of solder glasses were also investigated, using non-isothermal DTA techniques. The activation energies ranged from 220 to 235 kJ mol^-1 and the devitrification mechanism parameters were close to 1. This indicates that the devitrification mechanisms of the two kinds of solder glasses involve surface nuclei. This revised version was published online in July 2006 with corrections to the Cover Date.