Spontaneous-combustion propensity of New Zealand coals under adiabatic conditions

Pulverised New Zealand coal samples have been tested from an initial temperature of 40 degreesC and reacted adiabatisally in an oven with oxygen to provide a full temperature history of auto-oxidation up to the self-sustained process of combustion. This procedure produces a self-heating rate index, R-70, calculated as the ratio of the time taken to reach 70 degreesC (degreesC/h). The R-70 index is a measure of the coal's propensity to spontaneous combustion. R-70 values for New Zealand coals are much higher than any previously published results. They show a rank dependence, whereby subbituminous coals have the highest propensity to spontaneous combustion (14.91-17.23 degreesC/h). A lignite sample has an R-70 value of 7.76 degreesC/h, and high-volatile bituminous B coals have R-70 values of 0.31-2.23 degreesC/h. Samples stored for 2 years show the same rank trend. The nature of this trend is most likely a function of the internal surface area of the coal that governs the available sites for oxidation. Calculating the Suggate rank; for any New Zealand coal can be used to rare its propensity to spontaneous combustion. Resin bodies in the subbituminous coal show no propensity to spontaneous combustion. (C) 2001 Elsevier Science B.V. All rights reserved.

Ab initio modelling of basal plane oxidation of graphenes and implications for modelling char combustion

Ab initio calculations have been performed to determine the energetics of oxygen atoms adsorbed onto graphene planes and the possible reaction path extracting carbon atorns in the form of carbon monoxide. Front the energetics it is confirmed that this reaction path will not significantly contribute to the gasification of well ordered carbonaceous chars. Modelling results which explore this limit Lire presented. (C) 2002 Elsevier Science Ltd, All rights reserved.

Caractéristiques diphasiques des écoulements sur les coursiers en marches d'escalier

Stepped cascades and spillways have been used for more than 3,500 years. The recent regain of interest for the stepped chute design is associated with the introduction of new construction techniques, the development of new design techniques and newer applications. Stepped chute flows are characterised by significant free-surface aeration that cannot be neglected. Two-phase flow measurements were conducted in a large-size model (h =0.10 m, α = 22o). Experimental observations demonstrate the existence of a transition flow regime for a relatively wide range of flow rates. Detailed air-water flow measurements were conducted for both skimming flows and transition flows. Skimming flows exhibit gradual variations of the air-water flow properties, whereas transition flows are characterised by rapid flow redistributions between adjacent steps.

??cole Nationale d'Administration Publique: d??velopper les comp??tences des fonctionnaires pour augmenter la capacit?? de L'Etat dans la gestion des politiques publiques

Plus d???une vingtaine d???ann??es d???existence d??di??es ?? la mission de d??velopper les comp??tences des fonctionnaires pour augmenter la capacit?? de l?????tat dans la gestion des politiques publiques fait de l???ENAP un mod??le dans le domaine de la formation. Rattach??e au Minist??re du Plan, du Budget et de la Gestion, l?????cole, d??s sa cr??ation en 1986, a re??ue 245 mille fonctionnaires de tout le pays. En 2007, 26 mille fonctionnaires de l???administration f??d??rale ont attendu un de nos 60 stages offerts.

Recensão de: CHARLOT, Bernard (1999). Le Rapport au Savoir en milieu populaire. Une recherche dans les Lycées Professionnels de banlieue. Paris: Anthropos, 390 p.

Revista Lusófona de Educação

Intervenção social com as famílias = Intervention sociale avec les familles

RESUMO: Breve apresentação de uma família e sua problemática, beneficiária do Rendimento Social de Inserção, bem como as dificuldades que a técnica encontra no acompanhamento da mesma. ABSTRACT: Brief presentation of a family and set of problems raised by their social situation that receives a social subsidy for reinsertion, as well as the difficulties that the social worker encounters.

A escola e as famílias modernas = L'école et les familles modernes

RESUMO: Esta intervenção propõe-se apresentar as relações da escola da actualidade com as famílias dos alunos, com todas as dificuldades e desafios que estas relações implicam. Seguem-se a exposição de dois casos, dois alunos inseridos no Âmbito do projecto Novas Oportunidades. ABSTRACT: This intervention proposes to describe the relationships between School and student’s families of today, with their issues and challenges that are implied. It is followed by the presentation of two students within the context of New Opportunities programme.