Experimental Investigation of Heat Transfer in Components of a Hermetic Reciprocating Compressor under Thermal Transient

Heat transfer has an important role on the efficiency and reliability of hermetic reciprocating compressors adopted for household refrigeration. Most analyses of such compressors are carried out for fully-cyclic operating conditions based on established procedures and standards. However, since household refrigeration systems work by alternating periods in which the compressor is on (ON) and idle (OFF), the performance assessment of compressors should take into account the ON/OFF cyclic operation. This paper presents an experimental study of the heat transfer in components of a hermetic reciprocating compressor during thermal transients due to ON/OFF cyclic operation. The compressor was instrumented with thin-film heat flux sensors and thermocouples to evaluate time-varying heat transfer coefficients. We found that heat flux in some regions is significantly affected by the cyclic operating condition. Moreover, the investigation revealed the presence of different time scales due to distinct thermal inertia and heat transfer associated with each component

Programação e controle da produção na indústria de montagem: um sistema para pequenas e médias empresas

Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico. Programa de Pós-Graduação em Engenharia de Produçã

Gestão participativa e produtividade : uma abordagem da ergonomia

TESE (doutor) - Universidade Federal de Santa Catarina, Centro TecnologicoO título do trabalho "Gestão participativa e produtividade: uma abordagem da ergonomia", apresenta explicitamente os temas que estão sendo tratados. Pelas experiências vividas, pelos contatos realizados e pela revisão bibliográfica realizada foi constituído o entendimento que a gestão no futuro será, de alguma maneira, estabelecida com base em processos participativos. Isto passou a ser a primeira hipótese do trabalho. Ao buscar como os processos participativos estavam sendo obtidos apareceu de forma clara que os que estavam sendo experimentados apresentavam grandes conflitos. Frente a isto, passou a ser importante estudar formas de se obter processos participativos, que oferecessem resultados finais menos conflituosos reativamente. Os homens possuem, individualmente, limitações e capacidades. Na atividade de trabalho, se estas forem prioritariamente respeitadas, haverá uma tendência do homem a desempenhar suas atividades com maior criatividade, inteligência e com grandes possibilidades de desenvolver sistemas participativos com menos conflitos reativos, mantendo e até desenvolvendo a estrutura de conflitos proativos. Em outras palavras pode-se apresentar esta hipótese na seguinte forma: a ergonomia poderá ser uma plataforma para obtenção de sistemas participativos, ou ainda que os ambientes quando impregnados de ergonomia estarão mais propensos ao desenvolvimento de sistemas participativos. Com estas hipótese formuladas passou-se a estudar detalhada e aprofundadamente as questões da participação, produtividade, ergonomia, organização do trabalho, da qualidade de vida e das formas de gestão

Eco-innovation and technological cooperation in cassava processing companies: structural equation modeling

The generation of wealth, sustained by productive activities of agro-industries, leads to the production of wastes and uses natural resources, interfering in the environmental pillar of sustainability. The purpose of this study is to investigate whether cassava processing companies generate eco-innovations by means of technological cooperation, and the degree of participation of agents in these interactions. The quantitative method used the structural equation modeling for data analyses. The results indicated a relationship between technological cooperation and the generation of eco-innovation. The model developed showed the significance between variables and exposed the main aspects that generate eco-innovation from technological cooperation. A cooperation process allows a reduction in the burning of fossil fuels, reducing the emission of methane gas, which aggravates the greenhouse effect, also reducing odor, and ultimately, providing financial gains to agribusiness

PRODUCTION OF ETHYLIC BIODIESEL FROM HYDROLYSIS AND ESTERIFICATION OF ACID ANIMAL FAT

Biodiesel is a fuel derived from the oils and fats of plants and animals. Some vegetable oils after extraction and seed storing may have high acidity due to the conversion of triglycerides into free faty acids. Transesterification of high acidic oils with basic catalyst will form a large amount of soap as residue. The objective of this work is to study hydrolysis of tallow fats estherification free fatty acids followed by estherification of free fatty acids with ethanol using homogeneous catalyst. Tallow fat was hydrolyzed by enzyme lipase extracted from Ricinius Communs seeds. Estherification was done in a pressurizes reactor, at temperatures from 70°C to 130°C, ethanol/oil ratio from 2:1 to 4:1, amount of sulfuric acid catalyst from 0.2 to 0.8%, during 60 minutes of reaction. A factorial experimental design was carried out with three variables, two levels and replicas at central point. Results show that hydrolysis with enzymes during 24 hours at 40 oC was very effective to convert triglycerides into free fatty acids (FFA). In the estherification reaction, the yield of esther increased with the increasing of temperature, ethanol/oil ratio and catalyst concentration. Best results was obtained at 130 oC and 0.8% of catalyst in either concentration of ethanol, 2:1 or 4:1. The mains effects on the FFA conversion was temperature, acid concentrations and cross effects temperate and acid concentration. Keywords: biodiesel, estherification, tallow, free fatty acid

Análise multi-critério aplicada ao mapeamento da suscetibilidade a escorregamentos

This paper presents the application of a multi-criteria analysis (MCA) tool for landslide susceptibility assessment in Porto Alegre municipality, southern Brazil. A knowledge driven approach was used, aiming to ensure an optimal use of the available information. The landslide conditioning factors considered were slope, lithology, fl ow accumulation and distance from lineaments. Standardization of these factors was done through fuzzy membership functions, and evaluation of their relative importance for landslide predisposition was supported by the analytic hierarchy process (AHP), based on local expert knowledge. Finally, factors were integrated in a GIS environment using the weighted linear combination (WLC) method. For validation, an inventory, including 107 landslide points recorded between 2007 and 2013 was used. Results indicated that 8.2% (39.40 km²) of the study area are highly and very highly susceptible to landslides. An overall accuracy of 95% was found, with an area under the receiver operating characteristic (ROC) curve of 0.960. Therefore, the resulting map can be regarded as useful for monitoring landslide-prone areas. Based on the fi ndings, it is concluded that the proposed method is eff ective for susceptibility assessment since it yielded meaningful results and does not require extensive input data.Este estudo apresenta a aplicação de uma ferramenta de análise multi-critério para mapear a suscetibilidade a escorregamentos no município de Porto Alegre, sul do Brasil. Uma abordagem guiada pelo conhecimento de especialistas foi utilizada, com o intuito de otimizar a utilização das informações disponíveis. Os fatores condicionantes dos escorregamentos considerados foram declividade, litologia, acúmulo defl uxo e distância de lineamentos. A padronização desses fatores foi realizada por meio da aplicação de funções fuzzy e a importância relativa de cada um na predisposição do terreno a escorregamentos foi estabelecida com o apoio da técnica AHP (Analytic Hierarchy Process), com base no conhecimento de especialistas locais. Por fi m, a integração dos fatores em ambiente SIG se deu por meio do método denominado Combinação Linear Ponderada (WLC). Para validar os resultados, utilizou-se um mapa inventário contendo 107 cicatrizes de escorregamentos, registradas entre 2007 e 2013. Os resultados indicam que 8,2% (39,38 km²) da área de estudo possui uma suscetibilidade alta e muito alta a escorregamentos. A validação dos resultados obteve uma exatidão geral de 95%, com uma área abaixo da curva ROC (Receiver Operating Characteristic) de 0,960. Portanto, o mapa obtido pode ser considerado útil para monitorar as áreas propensas a esses processos. Com base nos resultados, conclui-se que o método proposto é efi caz para a avaliação da suscetibilidade, uma vez que os resultados obtidos são robustos e que não foi necessária uma quantidade extensa de dados de entrada

Human Trafficking and Prostitution in Mozambique: the Mualy, Amalapos and the Police

This article discusses processes of human trafficking for prostitution in Mozambique It begins by situating the African continent within the dynamics of globalization processes associating human trafficking with poverty and discussing it as a profitable illegal activity conducted on a global scale It continues by presenting the historical factors and economic constraints that put the Mozambican population in a vulnerable situation in relation to human trafficking and prostitution The article then examines how the perceptions of police regarding women trafficked for prostitution are affected by the local institution referred to as Mualy Quantitative data come from the Statistic Brain Research Institute compiled from the following reports UNAIDS World Bank and Demographic Dividend for the period of 2010 to 2017 Qualitative data were collected through ten interviews with the Provincial Command Squads of the Police of the Mozambique Republic PRM of Nampula a city located in northern Mozambique Results show that cultural factors interfere with how Mozambican police perceive human trafficking for prostitution and that such interferences undermine authorities strategies to combat this type of crim

Teaching NeuroImages: The Charcot shoulder Chiari malformation with syringomyelia associated with arthropathy

Univ Fed Sao Paulo, Dept Neurol & Neurosurg, Sao Paulo, BrazilUniv Fed Sao Paulo, Dept Orthoped & Traumatol, Sao Paulo, BrazilUniv Fed Sao Paulo, Dept Neurol & Neurosurg, Sao Paulo, BrazilUniv Fed Sao Paulo, Dept Orthoped & Traumatol, Sao Paulo, BrazilWeb of Scienc