Crystallization of 2RbBr · MnBr2 · 2H2O, the only double salt obtained under standard conditions from saturated aqueous rubidium–manganese bromide solutions, was theoretically predicted using the hard and soft Lewis acids and bases concept and Pauling's rules. The RbBr—MnBr2—H2O system was thermodynamically simulated by the Pitzer model assuming a solubility diagram of three branches only: RbBr, 2RbBr · MnBr2 · 2H2O and MnBr2 · 4H2O. The theoretical result was experimentally proved at 25°C by the physicochemical analysis method and formation of the new double salt 2RbBr · MnBr2 · 2H2O was established. It was found to crystallize in a triclinic crystal system, space group –P1, a = 5.890(1) Å, b = 6.885(1) Å, c = 7.367(2) Å, = 66.01(1)°, = 87.78(2)°, = 84.93(2)°, V = 271.8(1) Å3, Z = 1, Dx = 3.552 g-cm–3. The binary and ternary ion interaction parameters were calculated and the solubility isotherm was plotted. The standard molar Gibbs energy of the synthesis reaction, rG
mo
, of the double salt 2RbBr · MnBr2 · 2H2O from the corresponding simple salts RbBr and MnBr2 · 4H2O, as well as the standard molar Gibbs energy of formation, fG
mo
, and standard molar enthalpy of formation fH
mo
of the simple and double salts were calculated. 相似文献
The backward-facing step or the sudden expansion in internal flows is an important problem in different areas. In this study, a porous baffle is mounted on the opposite wall of a sudden expansion to enhance heat transfer near the step. Unlike the solid baffle, which is extensively studied in the literature, the porous baffle has a lower pressure drop, and its properties can be tuned to reach the optimal prospected performance. Effects of different porous baffle geometrical parameters including its normalized height (Hb?=?0.5, 1.0, 1.5, 1.75), width (Wb?=?0.5, 1, 1.5, 2.0, 2.5), porous baffle-step relative distance (D?=?1, 2, 3, 4), Darcy number (10?2, 10?3, 10?4, 10?6), and Reynolds number (100, 200, 300, 400, 500) on the heat transfer and pressure drop are investigated. The simulation indicates that higher Reynolds numbers enhance more the heat transfer (35% improvement at Re?=?500 with respect to 10% at Re?=?100). Also, longer baffles can lead to higher heat transfer rates (5% improvement in Hb?=?0.5 with respect to 32% at Hb?=?1.5).
Monatshefte für Chemie - Chemical Monthly - ?The data available on the solubility phase diagrams and on the crystallization of chloride and bromide double salts in the systems... 相似文献
Summary The rate of steel corrosion in hydrochloric acid solutions in the absence and in the presence of inhibitors is studied. It is found that the process dynamics is described by an exponential kinetic equation of self-accelerating reactions in the absence of inhibitor and by an equation of a zero order in its presence. 相似文献
Protein electric response signals (PERS) of the M intermediates of wild‐type bacteriorhodopsin (bR) were recorded. Contrary to earlier findings reporting on a single‐phase response upon excitation of the M intermediates, a kinetic analysis of the signals revealed the existence of three components, the fastest and the slowest ones of negative, while the middle one of positive sign with respect to the normal direction of proton pumping. Based on proton motion indicator experiments and molecular dipole calculations, the components were assigned to proton transfer steps and conformational changes driving the bR molecule back from the M to the ground state upon blue light excitation. The fastest, negative pump component was assigned to the proton transfer from D85 to the Schiff base. The subsequent positive component was attributed to rearrangements in the protein core (in the vicinity of the retinal molecule), triggered by the primary proton transfer process. The slowest component was established to reflect charge rearrangements associated with proton uptake by the protein from the bulk. 相似文献