In this paper, we introduce an analytical model for the temperature distribution of a diode side-pumped Nd:YAG laser rod by considering a Gaussian pump profile, taking into account the dependence of thermal conductivity on temperature. The stress and strain components are then derived by considering the dependence of the thermal expansion coefficient on the temperature. Our analytical model shows a very good agreement with numerical results. The maximum relative error, when compared with numerical results, is about 0.2 and 2.0% at the center of a laser rod for temperature and stress respectively.

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Two one-pot electrochemical approaches for the synthesis of similar quinone imines via either the nucleophilic character of N,N-dialkyl-p-phenylenediamines or electrophilic reactivity of their oxidized forms through Michael-type addition reactions are reported.

Hydroxylamine is used in the preparation of hydroxamates. A series of novel bicyclic hydroxamates have recently been discovered that could be useful for treating a broad range of inflammatory disorders.1 Modest levels of hydroxylamine can be toxic to humans, animals, and even plants. 2 Because of its bacteriotoxicity, government regulations have called for waste stream levels for hydroxylamine to be under low ppm level to ensure that local marine species are not endangered. Therefore, development of a sensitive analytical method for the determination of low levels of hydroxylamine is of significant importance from the industrial, environmental and health viewpoints.Several methods have been reported for the determination of hydroxylamine. Theses include spectrophotometry, 3-5 indirect potentiometry, 6 polarography, 7 HPLC, 8 biamperometry 9 and gas chromatography. 10 Kinetic methods of chemical analysis are attractive methods for rapid determination of trace amounts of inorganic species. 11,12 These methods have some advantages including high sensitivity, extremely low detection limit, good selectivity, rapid analysis and inexpensive instruments such as a spectrophotometer or spectrofluorometer. To our knowledge there is no report on the determination of hydroxylamine by kinetic methods.In this paper we propose a simple, rapid, accurate and precise method for the determination of hydroxylamine. The method is based on the oxidation of hydroxylamine with iodate, followed by the reaction of the produced nitrite ion with neutral red. Hydroxylamine as low as 0.040 µg mL -1 could be determined by the proposed method. Experimental ReagentsTriply distilled water and analytical-reagent grade chemicals were used. A 1000 µg mL -1 hydroxylamine stock solution was prepared by dissolving 0.2106 g of hydroxylamine hydrochloride (Merck) in water and diluting to the mark in a 100 mL volumetric flask. A 0.047 mol L -1 iodate solution was prepared by dissolving 1.0000 g of KIO3 (Merck) in water and diluting to 100 mL in a volumetric flask. A solution of 3.46 × 10 -4 mol L -1 neutral red was prepared by dissolving 0.01 g of neutral red (Merck) in water and diluting to 100 mL with water. A 3.0 M sulfuric acid solution was prepared by appropriate dilution of concentrated sulfuric acid (Merck). ApparatusA Perkin Elmer Lambda 45 UV/Vis spectrometer was used for recording absorbance spectra. Absorption measurements at fixed wavelength were performed using a Shimadzu Model UVmini-1240V spectrophotometer. ProcedureAll the solutions were equilibrated in a 25˚C thermostated water bath before beginning the reaction.The reaction was followed spectrophotometrically by monitoring the change in the absorbance at 525 nm. A suitable aliquot of sample solution containing 0.4 -12 µg hydroxylamine was transferred into a 10 ml volumetric flask. The solution was diluted to ca. 6 mL with water. Then 1 mL of 0.047 mol L -1 iodate solution was added followed by 1.0 mL of 3.0 mol L -1 sulfuric acid solution; the mixture was allowed to stand for 5 min at ro...

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