Performance comparativa entre R290/R600a (50:50) e R134a para drop-in em refrigerador doméstico

This research this based on the seminar on Use of Natural Fluids in Refrigeration and Air-Conditioning Systems conducted in 2007 in Sao Paulo. The event was inserted in the National Plan for Elimination of CFCs, coordinated by the Ministry of Environment and implemented by the United Nations Development Programme (UNDP). The objective of this research is analyze the performance of the hydrocarbons application as zeotropic mixtures in domestic refrigerator and validate the application of technical standards for pull down and cycling (on-off) tests to the mixture R290/R600a (50:50) in domestic refrigerator. It was first developed an computational analysis of R290/R600a (50:50) compared to R134a and other mass fractions of the hydrocarbons mixtures in the standard ASHRAE refrigeration cycle in order to compare the operational characteristics and thermodynamic properties of fluids based on the software REFPROP 6.0. The characteristics of the Lorenz cycle is presented as an application directed to zeotropic mixtures. Standardized pull down and cycling (on-off) tests were conducted to evaluate the performance of the hydrocarbons mixture R290/R600a (50:50) as a drop-in alternative to R134a in domestic refrigerator of 219 L. The results showed that the use of R290/R600a (50:50) with a charge of refrigerant reduced at 53% compared to R134a presents reduced energy performance than R134a. The COP obtained with hydrocarbon mixture was about 13% lower compared to R134a. Pull down times in the refrigerator compartments for fluids analyzed were quite close, having been found a 4,7% reduction in pull down time for the R290/R600a compared to R134a, in the freezer compartment. The data indicated a higher consumption of electric current from the refrigerator when operating with the R290/R600a. The values were higher than about 3% compared to R134a. The charge of 40 g of R290/R600a proved very low for the equipment analyzed

A indústria petrolífera nacional e potiguar: uma análise a partir da tecnologia em E&P

O trabalho analisa a Indústria Petrolífera em três ambientes de atuação, mundial, nacional e estadual, a partir da observação de sete variáveis, a saber: caráter do petróleo; risco; economia de escala; integração; barreiras; tecnologia e ambiente. O estudo busca perceber as interações e os transbordamentos das variáveis selecionadas em cada um dos ambientes citados, em razão os aspectos econômicos e institucionais presentes nesta atividade, cujos resultados atingem diversos setores da economia e da sociedade como um todo e balizam o próprio processo de inovação da mesma. O estudo está alicerçado no arcabouço teórico neoschumpeteriano acerca dos aspectos voltados para concorrência e inovação, além da questão institucional, e se apóia em dados da Agência Nacional do Petróleo (A.N.P.), Ministério de Minas e Energia (MME), Movimento de Combate à Corrupção Eleitoral / Tribunal Superior Eleitoral (MCCE/TSE), Organization of the Petroleum Exporting Countries (OPEC), International Energy Agency (IAE), Institut Français Pétrole (IFP), United Nations Development Programme (UNDP). Avalia-se que em termos de caracterização da indústria petrolífera nos três ambientes considerados (mundial, nacional e local), há certa similitude no que se refere ao comportamento destas variáveis, com pequenas modificações suscitadas por fatores como grau de desenvolvimento e complexidade da atividade; resultado do ambiente concorrencial e inovativo; e, pelas influências institucionais acerca de atividades e grau de inserção das mesmas no ambiente socioeconômico onde estão localizadas a atividade produtiva e o seu entorno

Políticas públicas de educação ambiental: a gestão do programa municipal de educação ambiental de Mossoró/RN

Study about environment education public policies, emphasizing the directress since the 1970 . It analyses the environment education administration of Mossoró city, indentifying its articulation with the international directresses and the Environment Education National Policy (PNEA), established according the law number 9.795/99. The text takes as empiric reference the Environment Education National Policy (PNEA) of Mossoró city, realized since 2006. In order to make the research, we employed as methodologic proceedings a bibliographical and documental revision from wich we developed a contextualization of the propolsals toward a environment Education policy and administration, the institution of the environment Education in Brazil, in the neoliberal context on the State reform ambit. We also employed a semi-structured interview, having as individuals two Environment Education Municipal Program Administration of Mossoró city / RN state administrators and nine Municipal Education System educators. The analysis was done from the historic and dialetic perspective, trying to understand the facts in its totallity. The results revealed that the environment Education has become to be emphasize as an environment crises superation strategy since the 1970 s. In this context, the environment Education administration directress, in the United Nations (UN) initiative ambit, emphasizes the participation and the partnership as a way to share responsabilities between the State and society. In the neoliberalism affirmation context, in the 1990 s, these directresses were fortified, once, since the State reform, their functions were redimensioned and the State turns into a stronger planner an controller, inducing the society to act as a public polcies executor. Therewith, a deconcentration action process is consolidated, rather than an administrative and pedagocgic decentralization, historically revendicated on Education by the progressist sectors. Even though the administrators interviewed have revealed the wish that the schools become autonomous on the PMEA execution, through the NEAs, we notice that the methods employed do not contribute to that, because of the decisions concentration on the associated managership ambit and the few human and financial resources. In spite of the difficulties, the research showed that the Mossoró municipality innovated on the environment Education field, by the institution of the NEAs, even though they demonstrate fragilities regarding their performance, revealed on the educators and adiminstration talk on the interviews. We verify that the main difficulties come from the politc culture installed on the municipality, ruled by a technocracy and power concentration wich brings difficulties to the implementation of a democratic and participative administration, even though it would not be totally impossible, even on the circumstances described