نتایج جستجو برای: enthalpy of hydrogen dissolution
تعداد نتایج: 21182932 فیلتر نتایج به سال:
Nanoscale Li and intermetallic Al-Mg metal hydride clusters are investigated as a possible hydrogen storage material using the high-level quantum Monte Carlo computational method. Lower level methods such as density functional theory are qualitatively, not quantitatively accurate for the calculation of the enthalpy of absorption of H(2). At sizes around 1 nm, it is predicted that Al/Mg alloyed ...
Recent years have witnessed renewed interest in the hydrogen economy, with emphasis n the metal/hydrogen system and its application to energy conversion efforts. Two ndustrially important aspects are emphasized, viz. the amount of hydrogen stored and the ate at which it can be transferred (absorbed/desorbed) because they are crucial factors in he design and construction of electrochemical energ...
The influence of ion dissolution in water is still controversial. The challenge posed to the existing concept of dissolved ions acting as water structure makers and structure breakers through recent studies calls for more experimental evidence. The temperature-dependent relaxation dynamics of water in bulk and in ionic salt solutions can give an idea about the hydrogen-bonded network and hence ...
A fundamental kinetic model for the hydrogenation of toluene over platinum has been constructed, based on detailed first-principles density functional theory calculations for the hydrogenation of benzene over Pt(111). A Langmuir–Hinshelwood–Hougen–Watson (LHHW) kinetic model was derived based on an ab initio reaction path analysis [M. Saeys, M.-F. Reyniers, M. Neurock, G.B. Marin, J. Phys. Chem...
While methanol and ethanol are macroscopically miscible with water, their mixtures exhibit negative excess entropies of mixing. Despite considerable effort in both experiment and theory, there remains significant disagreement regarding the origin of this effect. Different models for the liquid mixture structure have been proposed to address this behavior, including the enhancement of the water ...
We present results from first-principles calculations on silane (SiH4) under pressure. We find that a three dimensional P-3 structure becomes the most stable phase above 241 GPa. A prominent structural feature, which separates the P-3 structure from previously observed/predicted SiH4 structures, is that a fraction of hydrogen leaves the Si-H bonding environment and forms segregated H2 units. Th...
Reaction microcalorimetry and potentiometry have been used to define the thermodynamics of assembly of Escherichia coli aspartate transcarbamoylase (aspartate carbamoyltransferase, carbamoylphosphate:L-aspartate carbamoyltransferase, EC 2.1.3.2) from its catalytic and regulatory subunits and the linkage between assembly and proton binding. Over the pH range 7-9.5 and the temperature range 15-30...
پرداخت نفقه یکی از وظایف اساسی زوج در مقابل همسرش می باشد. علاوه بر دوران زوجیت، پس از انحلال نکاح در برخی از موارد، مرد همچنان موظف به پرداخت نفقه می باشد. در این پایان نامه به روش کتابخانه ای، به بررسی نفقه پس از انحلال نکاح پرداخته شده و سوال اصلی این است که در چه مواردی از انحلال نکاح مرد موظف به پرداخت نفقه می باشد؟ در قانون مدنی فقط به چند مورد از اسباب انحلال نکاح اشاره شده است ولی اسب...
The influence of preparation methodology of silymarin solid dispersions using a hydrophilic polymer on the dissolution performance of silymarin was investigated. Silymarin solid dispersions were prepared using HPMC E 15LV by kneading, spray drying and co-precipitation methods and characterized by FTIR, DSC, XRPD and SEM. Dissolution profiles were compared by statistical and model independent me...
The hydriding kinetics of hydrogen storage materials in the two-phase regions have been studied. It is believed that the hydriding process is best classified into three steps: dissolution of hydrogen into the alloy or its hydride; diffusion of hydrogen atoms through the alloy or its hydride phase; and nucleation and growth of B-hydride (hydride depositing from supersaturated a-solid solution). ...
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