Determination of thiourea and some of its organic derivatives with sodium vanadate, hexacyanoferrate(III), Cerium(IV) sulphate, manganese(III) and manganese(IV).
The determination of thiourea and some of its organic derivatives with sodium vanadate, hexacyanoferrate(III), cerium(IV) sulphate, manganese(III) and manganese(IV) is described. A mixture of iodate and iodide is used as catalyst. Ferroin, N-phenylanthranilic acid and p-ethoxychrysoidine can be used as indicators.
Determination of some organic thio-compounds by precipitation of mercuric sulphide from mercury(II) ammine complexes--II: determination of thiourea and some of its derivatives.
A gravimetric method based on precipitation of mercuric sulphide has been developed for determination of thiourea and some of its derivatives (acetylthiourea and sym-diphenylthiourea). Concentrated nitric acid is added to 0.1M mercuric nitrate, the solution is made alkaline with concentrated ammonia solution and thiourea (dissolved in concentrated ammonia solution), acetylthiourea (dissolved in methanol) or diphenylthiourea (dissolved in acetone) is added and the mixture is boiled. The precipitate is filtered off, washed, and dried at 110 degrees . The determination takes about 40 min. The method gives satisfactory results for thiourea and very good ones for diphenylthiourea and acetylthiourea.
Thermally Induced Dynamics of Satellite Solar Panels
Thermally induced structural motions are known to affect the attitude dynamics of low Earth orbiting satellites during eclipse transitions. Motions of e exible appendages such as solar panels lead to rigid body rotations of the entire satellite because the total angular momentum of the system is conserved. These potentially large attitude disturbances may violate pointing accuracy and jitter requirements. One type of thermally induced dynamics exhibited by solar panels is thermal snap. The Upper Atmosphere Research Satellite is a prominent example of a satellite that experiences thermal snap disturbances during eclipse transitions. This paper describes recent studies of thermally induced dynamicsof solarpanels, including an analysisofsatelliteattitudedynamics resulting from thermally induced structural motions and a laboratory investigation of the thermal-structural performance of a satellite solar panel. Analytical and experimental results demonstrate thermal bending deformations with acceleration transients that have characteristic thermal snap disturbance histories in response to rapid changes in heating. The studies show that solar panel thermal snap disturbances are caused by through-the-thickness temperature differences that vary at a nonconstant rate. Finite element analysis correctly predicts the thermal snap phenomenon observed in the solar panel experiments.