Modeling of phase equilibrium and vapor adsorption on carbon black based on a combination of a lattice theory and equation of state

A thermodynamic approach is developed in this paper to describe the behavior of a subcritical fluid in the neighborhood of vapor-liquid interface and close to a graphite surface. The fluid is modeled as a system of parallel molecular layers. The Helmholtz free energy of the fluid is expressed as the sum of the intrinsic Helmholtz free energies of separate layers and the potential energy of their mutual interactions calculated by the 10-4 potential. This Helmholtz free energy is described by an equation of state (such as the Bender or Peng-Robinson equation), which allows us a convenient means to obtain the intrinsic Helmholtz free energy of each molecular layer as a function of its two-dimensional density. All molecular layers of the bulk fluid are in mechanical equilibrium corresponding to the minimum of the total potential energy. In the case of adsorption the external potential exerted by the graphite layers is added to the free energy. The state of the interface zone between the liquid and the vapor phases or the state of the adsorbed phase is determined by the minimum of the grand potential. In the case of phase equilibrium the approach leads to the distribution of density and pressure over the transition zone. The interrelation between the collision diameter and the potential well depth was determined by the surface tension. It was shown that the distance between neighboring molecular layers substantially changes in the vapor-liquid transition zone and in the adsorbed phase with loading. The approach is considered in this paper for the case of adsorption of argon and nitrogen on carbon black. In both cases an excellent agreement with the experimental data was achieved without additional assumptions and fitting parameters, except for the fluid-solid potential well depth. The approach has far-reaching consequences and can be readily extended to the model of adsorption in slit pores of carbonaceous materials and to the analysis of multicomponent adsorption systems. (C) 2002 Elsevier Science (USA).

Analysis of adsorption data of graphitized thermal carbon black with a DFT-lattice gas theory

In this paper we analyzed the adsorption of gases and vapors on graphitised thermal carbon black by using a modified DFT-lattice theory, in which we assume that the behavior of the first layer in the adsorption film is different from those of second and higher layers. The effects of various parameters on the topology of the adsorption isotherm were first investigated, and the model was then applied in the analysis of adsorption data of numerous substances on carbon black. We have found that the first layer in the adsorption film behaves differently from the second and higher layers in such a way that the adsorbate-adsorbate interaction energy in the first layer is less than that of second and higher layers, and the same is observed for the partition function. Furthermore, the adsorbate-adsorbate and adsorbate-adsorbent interaction energies obtained from the fitting are consistently lower than the corresponding values obtained from the viscosity data and calculated from the Lorentz-Berthelot rule, respectively.

Pasture grazing by black-striped wallabies (Macropus dorsalis) in central Queensland

Black-striped wallabies (Macropus dorsalis) are uncommon to rare in most of their former range, yet in parts of central Queensland where they are still locally common they are regarded as a serious pasture pest. There is considerable pressure from cattle graziers to reduce their density because of the putative damage that they cause to cattle pasture. Here we examined the effects of this species and other herbivores on pasture by monitoring vegetation cover between 1993 and 1998 in exclosures in brigalow, and poplar box communities on three grazing properties in the Maranoa region. The exclosures selectively allowed access to either: all vertebrate grazers including cattle; rabbits, bettongs, and wallabies; rabbits and bettongs; no vertebrate grazers. The greatest effects on the structure and species composition of pasture were caused by cattle, but wallabies did consume commercially important quantities of grass at some times of the year. This conflicts with local opinion that sees wallabies as the major cause of pasture degradation. Herein lies the management problem that sees continued reduction in wallaby habitat, and fragmentation of the species.

Black and white and re(a)d all over again: Indigenous minstrelsy in contemporary Canadian and Australian theatre

This essay considers processes by which community identities are challenged by discussing the use of whiteface as an activist strategy in recent indigenous theatre in Canada and Australia. To understand whiteface, I employ Susan Gubar's notion of racechange, processes that test and even transgress racial borders. I also situate whiteface in relation to the history of blackface minstrelsy. Noting the ways these racial performances affirm the hierarchies of color and how power becomes invested in such color codings, the essay highlights indigenous employment of whiteface as a potential form of critical historiography. I then analyze how whiteface functions in two productions, Daniel David Moses's Almighty Voice and His Wife (1991) in Canada and the Queensland Theatre Company's 2000 revival of George Landen Dann's Fountains Beyond in Australia. My analysis posits that such indigenous performances of whiteface can affirm the identity of the marginalized other even as they destabilize the fixity of race and its meanings.

Quantification of Listeria spp. contamination on shell and flesh of cooked black tiger prawns (Penaeus monodon)

Aims: To quantify Listeria levels on the shell and flesh of artificially contaminated cooked prawns after peeling, and determine the efficacy of Listeria innocua as a model for L. monocytogenes in this system. Methods and Results: A L. monocytogenes and L. innocua strain were inoculated separately onto cooked black tiger prawns using two protocols ( immersion or swabbing with incubation). Prawns were peeled by two methods ( gloved hand or scalpel and forceps) and numbers of Listeria on shells, flesh and whole prawn controls were determined. Prawns were exposed to crystal violet dye to assess the penetration of liquids. Regardless of preparation method or bacterial strain there were ca 1log(10) CFU more Listeria per shell than per peeled prawn. Dye was able to penetrate to the flesh in all cases. Conclusions: Shell-on prawns may be only slightly safer than shell-off prawns. Listeria innocua is an acceptable model for L. monocytogenes in this system. Significance and Impact of the Study: Reduced risk from L. monocytogenes on prawns can only be assured by adequate hygiene or heating.

Modelo de gest??o do ambiente de TI aplicado ao IBGE

A arquitetura de inform??tica do IBGE busca refletir a evolu????o das Tecnologias da Informa????o e de Comunica????o (TIC) e vem sendo modificada ao longo dos anos, de maneira a manter - se um equil??brio entre os anseios e diretrizes institucionais e governamentais. A partir do aprendizado e do sucesso obtidos no Censo Demogr??fico 2010, o IBGE inova agora na forma de administrar sua ??rea de TIC, baseado em software especialista adquirido.O IBGE se beneficia da administra????o dos bens de inform??tica, da responsabilidade sobre contratos, da gest??o do patrim??nio, do uso otimizado dos softwares comerciais, da agilidade de obten????o de informa????es sobre o parque computacional instalado, do monitoramento on-line dos servi??os oferecidos pela TI, da economia de gastos com viagens para suporte t??cnico dentro dos estados e entre os mesmos, da reeduca????o de funcion??rios quanto ao uso de tecnologias, da forma organizada e planejada de trabalho e, portanto, da gest??o p??blica das TIC

Modelo de gest??o de capacita????o da Presid??ncia da Rep??blica: pool de capacita????o

A fun????o capacita????o passa a ser concebida dentro de uma nova proposta materializada no modelo Pool de Capacita????o que tem por objetivos aumentar a capacidade do processo, alinhar a ??rea de recursos humanos ??s estrat??gias institucionais e sintoniz??-la com a cultura organizacional e os cen??rios externos. O processo de capacita????o passa a operar de forma sist??mica, desconcentrada e articulada em rede interna e externa

Condom??nio de empregadores rurais: um novo modelo de contrata????o no meio rural

O Minist??rio do Trabalho e Emprego, por interm??dio de sua Secretaria de Inspe????o do Trabalho, vem desenvolvendo arrojado programa de metas, visando diminuir os altos ??ndices de informalidade na contrata????o de m??o-de-obra. Al??m de ilegal, tal situa????o provoca graves preju??zos aos trabalhadores. Visando superar este contexto no meio rural, a Secretaria de Inspe????o do Trabalho lan??ou o projeto denominado "Condom??nio de Empregadores". O Condom??nio de Empregadores ?? a uni??o de produtores rurais pessoas f??sicas, com a ??nica finalidade de contratar diretamente empregados rurais, sendo outorgados a um dos produtores poderes para contratar e gerir a m??o-de-obra em suas propriedades. Iniciado em julho de 1999, o projeto consiste na capacita????o dos auditores fiscais, no estabelecimento de parcerias com institui????es governamentais e n??o governamentais e na implanta????o desse novo modelo de contrata????o em ??mbito nacional. Com o apoio do Minist??rio P??blico do Trabalho, do Instituto Nacional de Seguridade Social e de entidades representativas dos trabalhadores e segmento patronal, j?? foram implantados condom??nios no Paran??, Minas Gerais e S??o Paulo. Espera-se at?? o final do ano a cria????o de condom??nios em quase todo o territ??rio nacional, com a regulariza????o de dezenas de milhares de v??nculos laborais

O impacto do modelo gerencial na Administra????o P??blica: um breve estudo sobre a experi??ncia internacional recente

Texto que focaliza o processo de surgimento e desenvolvimento do modelo gerencial (managerialism ou public management) no campo da administra????o p??blica, analisando seus limites e potencialidades, mediante a abordagem do caso ingl??s e americano de reformas administrativas de governo, ao longo das d??cadas de 80 e 90; ao final, al??m do perfil das principais mudan??as administrativas que t??m afetado o setor p??blico em escala mundial, um coment??rio breve sobre o caso brasileiro.

A jornada da aprendizagem: um guia para alcan??ar a excel??ncia; Um modelo canadense de administra????o p??blica?

Este Caderno traz dois relat??rios de pesquisa internacionais. O primeiro objetiva fazer um levantamento do que se sabe sobre organiza????es de aprendizagem, traduzir as informa????es resultantes em orienta????es pr??ticas e desenvolver abordagens que possam ajudar gerentes a transformar seus locais de trabalho. O segundo relat??rio objetiva verificar a exist??ncia de um modelo canadense de administra????o p??blica canadense, identificando suas principais caracter??sticas distintivas de outros modelos

Texto para discuss??o 35: modelo para informatiza????o das administra????es p??blicas municipais

O presente trabalho ?? resultado de um estudo onde observamos planos diretores de inform??tica e, considerando sua l??gica, verificamos que eles, na forma como s??o propostos para empresas do setor privado, n??o se aplicam ao setor p??blico

Texto para discuss??o 40: entre o p??blico e o privado: o modelo de gest??o de res??duos s??lidos adotados pela SLU de Belo Horizonte

O estudo empreende uma an??lise do programa de gera????o de renda e emprego embutido no modelo de gest??o de res??duos s??lidos da SLU de Belo Horizonte, focalizando os mecanismos de gest??o adotados e enunciando os principais problemas enfrentados pelos agentes envolvidos no processo. O trabalho procura explicitar o marco de refer??ncia utilizado para embasar a reflex??o do modelo de gest??o de res??duos s??lidos. Posteriormente, ?? apresentada a metodologia empregada. Na seq????ncia, encontra-se a descri????o propriamente dita do modelo de gest??o de res??duos s??lidos da SLU de Belo Horizonte, bem como dos seus impactos no que diz respeito ?? gera????o de emprego e renda, o que significa incluir a ASMARE como o outro p??lo da parceria. Aqui estar??o expostos os resultados relevantes da pesquisa, bem como a an??lise dos resultados e os coment??rios conclusivos encerrando a an??lise

Modelo de gest??o como processo de inova????o e aumento da produtividade

Aponta e descreve as diversas a????es implementadas que resultaram em redu????o do desperd??cio, aumento das receitas, assist??ncia de alto n??vel ao paciente, aprimoramento do ensino e da pesquisa com novos patamares quantitativos e qualitativos de desempenho, satisfa????o do corpo profissional, al??m de forte credibilidade junto ?? comunidade, decorrente do efetivo cumprimento dos seus objetivos institucionais