1000 resultados para 250199 Physical Chemistry not elsewhere classified


Relevância:

100.00% 100.00%

Publicador:

Resumo:

The physical chemistry of "aluminothermic" reduction of calcium oxide in vacuum is analyzed. Basic thermodynamic data required for the analysis have been generated by a variety of experiments. These include activity measurements in liquid AI-Ca alloys and determination of the Gibbs energies of formation of calcium aluminates. These data have been correlated with phase relations in the Ca-AI-0 system at 1373 K. The various stages of reduction, the end products and the corresponding equilibrium partial pressures of calcium have been established from thermodynamic considerations. In principle, the recovery of calcium can be improved by reducing the pressure in the reactor. However,, the cost of a high vacuum system and the enhanced time for reduction needed to achieve higher yields makes such a practice uneconomic. Aluminum contamination of calcium also increases at low pressures. The best compromise is to carry the reduction up to the stage where 3CaO-Al,O, is formed as the product. This corresponds to an equilibrium calcium partial pressure of 31.3 Pa at 1373 K and 91.6 Pa at 1460 K. Calcium can be extracted at this pressure using mechanical pumps in approximately 8 to 15 hr, depending on the size and the fill ratio of the retort and porosity of the charge briquettes.

Relevância:

100.00% 100.00%

Publicador:

Relevância:

100.00% 100.00%

Publicador:

Resumo:

These lectures are designed to show new students different lecturing styles they will encounter at Southampton University. This lecture is in the style of 'Chalk and Talk'. The lectures also teach students some of the fundamental parts of physics which are relevant to the Physical Chemistry course. This will be particularly useful for students who have forgotten their GCSE physics! To view the videos, download the zip file and 'extract' the contents by right clicking on the folder. Then double click on the file 'Play video.html'. Note that the video has been compressed heavily so it can be downloaded, which means there is a slight loss in quality. If you have a problem with this, please e-mail David Read (d.read@soton.ac.uk). NOTE: YOU MUST EXTRACT THE ZIP FOLDER BEFORE CLICKING ON 'Play video.html' OTHERWISE IT WON'T WORK.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

These lectures are designed to show new students different lecturing styles they will encounter at Southampton University. This lecture is delivered using a Tablet PC. These lectures also teach students some of the fundamental parts of physics which are relevant to the Physical Chemistry course. This will be particularly useful for students who have forgotten their GCSE physics! To view the videos, download the zip file and 'extract' the contents by right clicking on the folder. Then double click on the file 'Play video.html'. Note that the video has been compressed heavily so it can be downloaded, which means there is a slight loss in quality. If you have a problem with this, please e-mail David Read (d.read@soton.ac.uk). NOTE: YOU MUST DOWNLOAD AND EXTRACT THE ZIP FOLDER BEFORE CLICKING ON 'Play video.html' OTHERWISE IT WON'T WORK.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

These lectures are designed to show new students different lecturing styles they will encounter at Southampton University. This lecture is delivered using PowerPoint. These lectures also teach students some of the fundamental parts of physics which are relevant to the Physical Chemistry course. This will be particularly useful for students who have forgotten their GCSE physics! To view the videos, download the zip file and 'extract' the contents by right clicking on the folder. Then double click on the file 'Play video.html'. Note that the video has been compressed heavily so it can be downloaded, which means there is a slight loss in quality. If you have a problem with this, please e-mail David Read (d.read@soton.ac.uk). NOTE: YOU MUST DOWNLOAD AND EXTRACT THE ZIP FOLDER BEFORE CLICKING ON 'Play video.html' OTHERWISE IT WON'T WORK.

Relevância:

100.00% 100.00%

Publicador:

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The first IUPAC Manual of Symbols and Terminology for Physicochemical Quantities and Units (the Green Book) of which this is the direct successor, was published in 1969, with the object of 'securing clarity and precision, and wider agreement in the use of symbols, by chemists in different countries, among physicists, chemists and engineers, and by editors of scientific journals'. Subsequent revisions have taken account of many developments in the field, culminating in the major extension and revision represented by the 1988 edition under the simplified title Quantities, Units and Symbols in Physical Chemistry. This 2007, third edition, is a further revision of the material which reflects the experience of the contributors with the previous editions. The book has been systematically brought up to date and new sections have been added. It strives to improve the exchange of scientific information among the readers in different disciplines and across different nations. In a rapidly expanding volume of scientific literature where each discipline has a tendency to retreat into its own jargon this book attempts to provide a readable compilation of widely used terms and symbols from many sources together with brief understandable definitions. This is the definitive guide for scientists and organizations working across a multitude of disciplines requiring internationally approved nomenclature.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

This Account covers research dating from the early 1960s in the field of low-melting molten salts and hydrates,which has recently become popular under the rubric of “ionic liquids”. It covers understanding gained in the principal author’s laboratories (initially in Australia, but mostly in the U.S.A.) from spectroscopic, dynamic, and thermodynamic studies and includes recent applications of this understanding in the fields of energy conversion and biopreservation. Both protic and aprotic varieties of ionic liquids are included, but recent studies have focused on the protic class because of the special applications made possible by the highly variable proton activities available in these liquids.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Avaliou-se a composição centesimal e análise físico-química do Lentinus strigosus, um cogumelo comestível de ocorrência na Amazônia brasileira, produzidos em substratos alternativos à base de resíduos madeireiros e agroindustriais. Com este objetivo, determinou-se C, N, pH, sólidos solúveis, atividade de água, proteína, lipídios, fibra total, cinzas, carboidratos e energia. Os substratos foram formulados a partir de serragem de Simarouba amara Aubl. (marupá), Ochroma piramidale Cav. ex. Lam. (pau-de-balsa) e Anacardium giganteum (cajuí); e do estipe de Bactris gasipaes Kunth (pupunheira) e de Saccharum officinarum (cana-de-açúcar). Os resultados demonstraram que: a composição nutricional do L. strigosus variou com o substrato de cultivo; os valores de proteína encontrados nos cogumelos cultivados nos diferentes substratos (18 - 21,5%) variaram de acordo com o substrato, sendo considerados elevados; os sólidos solúveis presentes nos cogumelos podem ter relação com vitaminas hidrossolúveis do complexo B; o L. strigosus pode ser considerado um importante alimento devido suas características nutricionais: alto teor de proteína, carboidratos metabolizáveis e fibras; baixos teores de lipídios e de calorias.