Global oil peaking: responding to the case for 'abundant supplies of oil'

This paper examines aspects of the case against global oil peaking, and in particular sets out to answer a viewpoint that the world can have abundant supplies of oil "for years to come". Arguments supporting the latter view include: past forecasts of oil shortage have proved incorrect, so current predictions should also be discounted; many modellers depend on Hubbert's analysis but this contained fundamental flaws; new oil supply will result from reserves growth and from the wider deployment of advanced extraction technology; and that the world contains large resources of unconventional oil that can come on-stream if the production of conventional oil declines. These arguments are examined in turn and shown to be incorrect, or to need setting into a broader context. The paper concludes therefore that such arguments cannot be used to rule out calculations that the resource-limited peak in the world's production of conventional oil will occur in the near term. Moreover, peaking of conventional oil is likely to impact the world's total availability of oil where the latter includes non-conventional oil and oil substitutes. (C) 2008 Elsevier Ltd. All rights reserved.

In vitro gas production and nitrogen degradability of tannin-containing tree fruits in response to incremental levels of polyethylene glycol

This study was designed to determine the response of in vitro fermentation parameters to incremental levels of polyethylene glycol (PEG) when tanniniferous tree fruits (Dichrostachys cinerea, Acacia erioloba, A. erubiscens, A. nilotica and Piliostigma thonningii) were fermented using the Reading Pressure Technique. The trivalent ytterbium precipitable phenolics content of fruit substrates ranged from 175 g/kg DM in A. erubiscens to 607 g/kg DM in A. nilotica, while the soluble condensed tannin content ranged from 0.09 AU550nm/40mg in A. erioloba to 0.52 AU550nm/40 mg in D. cinerea. The ADF was highest in P. thonningii fruits (402 g/kg DM) and lowest in A. nilotica fruits (165 g/kg DM). Increasing the level of PEG caused an exponential rise to a maximum (asymptotic) for cumulative gas production, rate of gas production and nitrogen degradability in all substrates except P. thonningii fruits. Dry matter degradability for fruits containing higher levels of soluble condensed tannins (D. cinerea and P. thonningii), showed little response to incremental levels of PEG after incubation for 24 h. The minimum levels of PEG required to maximize in vitro fermentation of tree fruits was found to be 200 mg PEG/g DM of sample for all tree species except A. erubiscens fruits, which required 100 mg PEG/g DM sample. The study provides evidence that PEG levels lower than 1 g/g DM sample can be used for in vitro tannin bioassays to reduce the cost of evaluating non-conventional tanniniferous feedstuffs used in developing countries in the tropics and subtopics. The use of in vitro nitrogen degradability in place of the favoured dry matter degradability improved the accuracy of PEG as a diagnostic tool for tannins in in vitro fermentation systems.

Does SMS text messaging help or harm adults’ knowledge of standard spelling?

The recent increase in short messaging system (SMS) text messaging, often using abbreviated, non-conventional ‘textisms’ (e.g. ‘2nite’), in school-aged children has raised fears of negative consequences of such technology for literacy. The current research used a paradigm developed by Dixon and Kaminska, who showed that exposure to phonetically plausible misspellings (e.g. ‘recieve’) negatively affected subsequent spelling performance, though this was true only with adults, not children. The current research extends this work to directly investigate the effects of exposure to textisms, misspellings and correctly spelledwords on adults’ spelling. Spelling of a set of key words was assessed both before and after an exposure phase where participants read the same key words, presented either as textisms (e.g. ‘2nite’), correctly spelled (e.g. ‘tonight’) or misspelled (e.g. 'tonite’)words. Analysis showed that scores decreased from pre- to post-test following exposure to misspellings, whereas performance improved following exposure to correctly spelled words and, interestingly, to textisms. Data suggest that exposure to textisms, unlike misspellings, had a positive effect on adults’ spelling. These findings are interpreted in light of other recent research suggesting a positive relationship between texting and some literacy measures in school-aged children.

Who adopts Green Revolution (GR) technology in Ghana?

Sub-Saharan Africa in general and Ghana in particular, missed out on the Green revolution. Efforts are being made to re-introduce the revolution, and this calls for more socio-economic research into the factors influencing the adoption of new technologies, hence, this study. The study sought to find out how socio-economic factors contribute to adoption of Green revolution technology in Ghana. The method of analysis involved a maximum likelihood estimation of a probit model. The proportion of Green revolution inputs was found to be greater for the following: households whose heads had formal education, households with higher levels of non-farm income, credit and labor supply as well as those living in urban centers. It is recommended that levels of complementary inputs such as credit, extension services and infrastructure are increased. Also, households must be encouraged to form farmer-groups as an important source of farm labor. Furthermore, the fundamental problems of illiteracy must be addressed through increasing the levels of formal and non-formal education; and the gap between the rural and urban centers must be bridged through infrastructural and rural development. However, care must be taken to ensure that small-scale farmers are not marginalized, in terms of access to these complementary inputs that go with effective adoption of new technology. With these policies well implemented, Ghana can catch up with her Asian counterparts in this re-introduction of the revolution.

Adoption of green revolution services and poverty reduction in Ghana

In Sub-Saharan Africa (SSA) the technological advances of the Green Revolution (GR) have not been very successful. However, the efforts being made to re-introduce the revolution call for more socio-economic research into the adoption and the effects of the new technologies. The paper discusses an investigation on the effects of GR technology adoption on poverty among households in Ghana. Maximum likelihood estimation of a poverty model within the framework of Heckman's two stage method of correcting for sample selection was employed. Technology adoption was found to have positive effects in reducing poverty. Other factors that reduce poverty include education, credit, durable assets, living in the forest belt and in the south of the country. Technology adoption itself was also facilitated by education, credit, non-farm income and household labour supply as well as living in urban centres. Inarguably, technology adoption can be taken seriously by increasing the levels of complementary inputs such as credit, extension services and infrastructure. Above all, the fundamental problems of illiteracy, inequality and lack of effective markets must be addressed through increasing the levels of formal and non-formal education, equitable distribution of the 'national cake' and a more pragmatic management of the ongoing Structural Adjustment Programme.

Tetragonal and helical morphologies from polyferrocenylsilane block polyelectrolytes via ionic self-assembly

The use of ionic self-assembly, a facile noncovalent approach, to access non-conventional block copolymer morphologies, including tetragonal and helical structures, from a combination of polyferrocenylsilane diblock copolymer polyelectrolytes and AOT-based surfactants, is described.

A mudança de comportamento do setor público após o choque mundial de 1975 como resultado de conflitos sociais

O objetivo deste trabalho é duplo: verificar se a mudança de comportamento do setor público foi afetada pelo processo de ajuste que a economia mundial passou após o choque de 1975 e se a mesma foi explicada por variáveis macroeconomicamente pouco convencionais como distribuição de renda e eficiência da burocracia. Os resultados mostram que a mudança estrutural da economia em 1975 não foi significativa enquanto que a distribuição de renda e eficiência da burocracia foram: pior (melhor) distribuição de renda e melhor (pior) eficiência da burocracia levaram o setor público a um ajustamento (expansão). Testou-se ainda um 'mix' entre as variáveis usadas para representar a mudança estrutural, distribuição de renda e eficiência da burocracia. Fez-se isto para ver se esta mudança estrutural, combinada a estas variáveis, que seriam mais estáveis ao longo do tempo, influenciariam o resultado deste comportamento. Viu-se que variáveis de mudança estrutural combinadas com distribuição de renda e eficiência da burocracia foram significativas para explicar a mudança de comportamento do setor público sem alterar o sinais dos resultados obtidos pelas variáveis que foram significativas isoladamente. O 'mix' de variáveis de mudança estrutural e cada uma das variáveis alternadamente não foi: seu resultado não foi significativo ou foi de intuição não muito simples.

Caracterização para o beneficiamento do carvão de Candiota

O presente trabalho apresenta estudos sistemãticos da caracterização do carvão de Candiota em termos do seu beneficiamento. O carvão de Candiota possui caracteristicas de moabilidade que o indicam como bastantefriável. A geração de finos (-28 malhas) atinge valores superiores a 20% independente do grau de britagem . As distribuições granulométricas resultantes da britagem do carvão obedecem a equação de ROSIN-RAIIMLER-BENNETT, dentro do intervalo previsto (frações menores do ue -4 malhas e maiores do que 100 malhas). Os valores de n e d ' não variam significativamente com a abertura do britador o, que evidencia sua friabiliade. foram estabelecidas equações que relacionam aberturado britador, coeficientes de distribuição e diâmetro médio.Estudos rni croscópicos demonstraram que, o grau de d i-s seminação da matéria inorgânica é muitointenso , e sua liberação atinge malhas muito pequenas (provavelmente menores do que 400 malhas). O teor de cinzas, como por exemplo do grau de disseminação, não variou significativamente com a diminuição de tamanho, como acontece com outros carvões. Foram estabelecidos dois critérios de liberação das particulas em função da quantidade de matéria carbonosa presente nas unidades mistas (20 - 80% e 5 - 95%, respectivamente). Estes indices de partyculas mistas (5 - 95% de matéria carbonosa) mantiveram-se constantes até tamanhos aproximados de 115 malhas, para logo diminuirem nas frações menores. Ainda assim, para frações menores do que 53 micrômetro a quantidade de mistos ( 5 - 95%) foi de 34%. As curvas de lavabilidade deste carvão (tanto da fração grossa quanto afina), reflexo das caracteristicas anteriores, indicam-no como de muito dificil beneficiamento (lavagem). Isto basicamente é devido ao alto grau de "near gravity matterial" presente e de seu grau de liberação. 0s testes de jigagem por bateladas, bem como outros processos de beneficiamento, demonstraram a dificuldade do beneficiamento deste carvão. O melhor teste de jigagem por bateladas, obteve uma recuperação de materia carbonosa de 73, 21 com um teor de cinzas de 45,51 no concretado (alimentação contendo 50% de cinzas). de 37,59% de cinzas (alimentação de 50% de cinzas). Propõe-se, finalmente, um circuito de beneficiamento convencional do carvão de Candiota, incluindo uma classificação do carvão ROM com o objetivo de separar a alimentação em duas frações (+28 e -28 malhas), seguido de um processo de beneficiamento das frações grosseiras por meios densos (tanques), e um tratamento das frações finas por hidrociclonagem. Os resultados obtidos concluem que o carvão de Candiota é o mais dificil de ser lavado dentre os carvões sul-brasileiros devido ao alto teor de cinzas e ao grau de disseminação, sendo que este teor de cinzas não varia muito com a granulometria, o que implica em um grau de liberação muito baixo. Sugere- se como outra alternativa no seu beneficiamento, o estudo de processos não convencionais que incluem um alto grau de cominuiçáo ate completa liberação.

Essays on the credit channel of monetary policy: a case study for Brazil

The onset of the financial crisis in 2008 and the European sovereign crisis in 2010 renewed the interest of macroeconomists on the role played by credit in business cycle fluctuations. The purpose of the present work is to present empirical evidence on the monetary policy transmission mechanism in Brazil with a special eye on the role played by the credit channel, using different econometric techniques. It is comprised by three articles. The first one presents a review of the literature of financial frictions, with a focus on the overlaps between credit activity and the monetary policy. It highlights how the sharp disruptions in the financial markets spurred central banks in developed and emerging nations to deploy of a broad set of non conventional tools to overcome the damage on financial intermediation. A chapter is dedicated to the challenge face by the policymaking in emerging markets and Brazil in particular in the highly integrated global capital market. This second article investigates the implications of the credit channel of the monetary policy transmission mechanism in the case of Brazil, using a structural FAVAR (SFAVAR) approach. The term “structural” comes from the estimation strategy, which generates factors that have a clear economic interpretation. The results show that unexpected shocks in the proxies for the external finance premium and the credit volume produce large and persistent fluctuations in inflation and economic activity – accounting for more than 30% of the error forecast variance of the latter in a three-year horizon. Counterfactual simulations demonstrate that the credit channel amplified the economic contraction in Brazil during the acute phase of the global financial crisis in the last quarter of 2008, thus gave an important impulse to the recovery period that followed. In the third articles, I make use of Bayesian estimation of a classical neo-Keynesian DSGE model, incorporating the financial accelerator channel developed by Bernanke, Gertler and Gilchrist (1999). The results present evidences in line to those already seen in the previous article: disturbances on the external finance premium – represented here by credit spreads – trigger significant responses on the aggregate demand and inflation and monetary policy shocks are amplified by the financial accelerator mechanism. Keywords: Macroeconomics, Monetary Policy, Credit Channel, Financial Accelerator, FAVAR, DSGE, Bayesian Econometrics

O impacto da quantitative easing americano no preço dos ativos brasileiros

Aplicando uma metodologia de testes de eventos, este estudo avalia o impacto dos anúncios de implementação e retirada dos estímulos monetários pelo Banco Central americano (FED) entre 2008 a 2013 sobre a curva de juros, a taxa de câmbio e a bolsa brasileira. Os resultados mostram que os anúncios de política monetária americana impactaram o preço dos ativos brasileiros significativamente principalmente durante o QE1 e o Tapering. Para os demais QEs, Operação Twist e eventos de postergação da retirada de estímulos, o não Tapering, ainda que os resultados encontrados estivessem dentro do esperado, eles tiveram baixa significância. Concluímos que a política monetária americana não convencional foi eficaz em impactar o preço dos ativos brasileiros, em especial os eventos não esperados. Ao incluirmos defasagens nos testes aplicados concluímos que em alguns casos houve “atraso” na incorporação das novas informações no preço dos ativos.

Estudo de inibidores de corrosão em concreto armado, visando a melhoria na sua durabilidade

This thesis has as objective presents a methodology to evaluate the behavior of the corrosion inhibitors sodium nitrite, sodium dichromate and sodium molybdate, as well as your mixture, the corrosion process for the built-in steel in the reinforced concrete, through different techniques electrochemical, as well as the mechanical properties of that concrete non conventional. The addition of the inhibitors was studied in the concrete in the proportions from 0.5 to 3.5 % regarding the cement mass, isolated or in the mixture, with concrete mixture proportions of 1.0:1.5:2.5 (cement, fine aggregate and coarse aggregate), superplasticizers 2.0 % and 0.40 water/cement ratio. In the modified concrete resistance rehearsals they were accomplished to the compression, consistence and the absorption of water, while to analyze the built-in steel in the concrete the rehearsals of polarization curves they were made. They were also execute, rehearsals of corrosion potential and polarization resistance with intention of diagnose the beginning of the corrosion of the armors inserted in body-of-proof submitted to an accelerated exhibition in immersion cycle and drying to the air. It was concluded, that among the studied inhibitors sodium nitrite , in the proportion of 2.0 % in relation to the mass of the cement, presented the best capacity of protection of the steel through all the studied techniques and that the methodology and the monitoring techniques used in this work, they were shown appropriate to evaluate the behavior and the efficiency of the inhibitors

O pedagogo como agente de transformação social para além dos muros escolares

This thesis concerns the problem about the pedagogue actuation in the social education into no scholars places. It search to understand the context and the social pedagogue role to his praxis and formation that enlarger the possibilities of the social educative practices into no scholars places. In this direction, we developed an investigation about the actuation of the pedagogues-educators in Natal city, in the 2007-2010 periods, into Municipal Secretary of the Labor and Social Assistance (SEMTAS). Considering that pedagogues are regularly attached in social educators profession as municipals public employees, we re the objective to evaluate their role into the social executed in the no scholars places, with the focus in the environmental dimensions of theirs work s places, pedagogical organization, institutional management and the professional formation. It privileged in this research the Specialized Reference Center of Social Assistance II (CREAS II), the Passages Houses I, II and III, the Social-Educative Measures in Open Environment Execution Program of Natal city (PENSEMA) and the Pitimbú Educational Center (CEDUC-Pitimbú). To realize this study it developed a research with qualitative nature by critic ethnography approach privileging those information collected with the social pedagogue-educators of the mentioned places. Through the methodological procedures adopted; beyond the bibliographical review we remarked the documental research, the semi-structured interview, the questionnaires-routes and the field observations. The analytical results revealed that the politics to the social education in Brazil historically came been dimensioned by the fight of social movements demanding the fundamental rights to the excluded people; that the SEMTAS politics of social education present a relative basic social protection to the excluded children and young people specially into law view; that the politics of social education in Natal city it s close of the logic of sanitarian attention about the disadvantaged groups; that the conceptual, methodological and formatives fragilities needs to the social pedagogues-educators praxis into non scholars places made difficult the operation capacity of a educative proposition anchored in a institutional action guided by the idea of emancipator education; that the SEMTAS take face several difficulties to developed a web assistance as preview in the reception proposition elaborated by the social pedagogues-educators. However in despite the tensions we remarked the value of this potentiality to the non scholar social education in her attempt to constitute herself in a legitimate space to the pedagogue professional actuation. In despite the obstacles to work and formation quotidian, across those non scholar spaces in the municipalities institutes to the social politics, it demonstrated personal sensibility and professional creativity in learning mediations and educative action to the children and younger derived from exclusion process and the social iniquities

Avaliação de um programa de educação ambiental não formal: a Caravana Ecológica na visão dos participantes

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Controlador preditivo não linear aplicado ao controle de golfadas em processos de produção de petróleo

Slugging is a well-known slugging phenomenon in multiphase flow, which may cause problems such as vibration in pipeline and high liquid level in the separator. It can be classified according to the place of its occurrence. The most severe, known as slugging in the riser, occurs in the vertical pipe which feeds the platform. Also known as severe slugging, it is capable of causing severe pressure fluctuations in the flow of the process, excessive vibration, flooding in separator tanks, limited production, nonscheduled stop of production, among other negative aspects that motivated the production of this work . A feasible solution to deal with this problem would be to design an effective method for the removal or reduction of the system, a controller. According to the literature, a conventional PID controller did not produce good results due to the high degree of nonlinearity of the process, fueling the development of advanced control techniques. Among these, the model predictive controller (MPC), where the control action results from the solution of an optimization problem, it is robust, can incorporate physical and /or security constraints. The objective of this work is to apply a non-conventional non-linear model predictive control technique to severe slugging, where the amount of liquid mass in the riser is controlled by the production valve and, indirectly, the oscillation of flow and pressure is suppressed, while looking for environmental and economic benefits. The proposed strategy is based on the use of the model linear approximations and repeatedly solving of a quadratic optimization problem, providing solutions that improve at each iteration. In the event where the convergence of this algorithm is satisfied, the predicted values of the process variables are the same as to those obtained by the original nonlinear model, ensuring that the constraints are satisfied for them along the prediction horizon. A mathematical model recently published in the literature, capable of representing characteristics of severe slugging in a real oil well, is used both for simulation and for the project of the proposed controller, whose performance is compared to a linear MPC