Flow-through cell based on an array of gold microelectrodes obtained from modified integrated circuit chips

The construction of a flow-through cell incorporating an array of gold microelectrodes is described and its application to flow injection analysis with amperometric detection is presented, Simple modification of almost any conventional integrated circuit chip, used as an inexpensive source of pre-assembled gold micro-wires, leads to the rapid and successful preparation of arrays of 8-48 elements, the polymeric encapsulation material from the top face of the chip is removed by abrasion until the gold micro-mires (used to interconnect the silicon circuit to the external contact pins of the chip) are disrupted and their transversal (elliptical) sections become exposed. Once polished, the flat and smooth top surface of the gold microelectrode-array chip (MEAC) is provided with a spacer and fitted under pressure against an acrylic block with the reference and auxiliary electrodes, to form the electrochemical (thin-layer) flow cell, while the contact pins are plugged into a standard IC socket, This design ensures autonomous electric contact with each electrode and allows fast dismantling for polishing or substitution, the performance of flow cells with MEACs was investigated utilizing the technique of reverse pulse amperometry without oxygen removal, A method was established for the determination of the copper concentration in sugar cane spirit, regulated by law for beverages, Samples from industrial producers and small-scale (alembic) brewers were compared, With a 24 MEAC, a detection limit of 30 mu g I-l of copper (4.7 x 10(-7) mol l(-1) of Cu-II for 100 mu l injections) was calculated, Routine operation was established at a frequency of 60-90 determinations per hour, Intercomparison with atomic absorption spectrometric determinations resulted in excellent agreement.

Viabilidade de aplicação das coberturas argilosas da região de Alfenas na indústra cerâmica

The region of Alfenas, in the state of Minas Gerais, Brazil, is predominantly constituted of Pre-Cambrian rocks with well developed alteration profiles in association with colluvial and alluvial sediments. No study to date has examined in detail its potential use in the ceramic industry. The scarce knowledge of its mineralogical and technological properties limits its value and consequently its industrial use. Until now, these clay materials have been used in a rudimental manner, in small scale in the fabrication of red tiles. The present study aimed at analyzing these clays mineralogically (X-ray diffraction), chemically (major and minor elements by X-ray fluorescence and organic carbon analysis) and technologically (pressing granulometric distribution; mechanical resistence; water absorption, apparent porosity; linear firing shrinkage; color of firing and others) in order to better understand the raw material and develop adequate technological applications. The best results of ceramic properties were the samples with higher organic content (more plastic clays) and higher values of Al2O3 (kaolinite and gibbsite) and Fe2O3 as well lower SiO2 content and finer grain size which contribute to a better sinterization.

The Brazilian architecture in wood and the confrontations with the questions of the environment

Two discussions are imposed to the designers of wood constructions. The first one deals with the technical knowledge to project and execute buildings; the second one is concerned with the preservation of the environment, use of the wood in a sustainable way. The work presents the tendencies of the wood used in the Brazilian habitation architecture characterizing the used woods; how the construction technical solutions have developed and discusses about the necessity of using the wood in a conscious way, knowing its origin and control, sustainable use of the forests resources. It focalizes, mainly, the search of the designers to harmonize the use of the wood and the preservation of the forest biodiversity, when it deals with the native forest.

Training and the small enterprises of Latin America

Includes bibliography

Corpo, ciência e educação: representações do corpo junto a jovens estudantes e seus professores

Pós-graduação em Educação para a Ciência - FC

Análise dos impactos na construção civil: avaliação do ciclo de vida em chapas de partículas para forros

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Problema integrado de dimensionamento de lotes e corte de estoque na indústria moveleira

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

As usinas hidrelétricas e seus impactos: os aspectos socioambientais e econômicos do reassentamento rural de Rosana-Euclides da Cunha Paulista

Pós-graduação em Geografia - FCT

Innovación sustentable: espacios para mejorar la competitividad de las PYMES argentinas

Incluye bibliografía.

Análise energética de sistemas de produção de etanol de mandica,cana-de-açúcar e milho

Pós-graduação em Agronomia (Energia na Agricultura) - FCA

Estanho na Amazônia: o apogeu e o caso da produção

No Brasil, na Região Amazônica, o minério de estanho (cassiterita) é obtido por dragagem em depósitos aluvionares, extração de minério primário e lavra de pequeno porte. O concentrado de estanho obtido (Sn02, contendo 60% de estanho), sendo transformado, via redução, nos fornos elétricos, transformando-o em lingotes de estanho. O metal é primeiramente usado para a produção de folhas de flandres – chapas de aço recobertas com estanho e utilizadas para fabricação de latas para alimentos, bebidas e produtos químicos, bem como na produção de soldas e outras ligas para a indústria em geral (particularmente em segmentos elétricos e eletrônicos). A mina mais importante é a de Pitinga (pureza de 55,3%), localizada a 300 km ao norte de Manaus (AM) e proprietária da Paranapenema. Pitinga dispõe de reservas provadas de columbita-tantalita, criolita e zirconita, contendo terras raras e itrium, cuja viabilidade econômica ainda está sendo estudada. Há inda veios mineralizados no estado de Rondônia, incluindo a mina de Bom Futuro (pureza de 58%), no município de Ariquemes, onde operam os mineradores de pequeno porte. O Brasil é o quinto maior produtor do metal, após Indonésia, China e Peru.

Qualificação profissional e sindicatos. Entre estado, capital e trabalho: um estudo de casos no meio rural de Ribeirão Preto

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

The contribution of multiple use forest management to small farmers' annual incomes in the Eastern Amazon

Small-scale farmers in the Brazilian Amazon collectively hold tenure over more than 12 million ha of permanent forest reserves, as required by the Forest Code. The trade-off between forest conservation and other land uses entails opportunity costs for them and for the country, which have not been sufficiently studied. We assessed the potential income generated by multiple use forest management for farmers and compared it to the income potentially derived from six other agricultural land uses. Income from the forest was from (i) logging, carried out by a logging company in partnership with farmers' associations; and (ii) harvesting the seeds of Carapa guianensis (local name andiroba) for the production of oil. We then compared the income generated by multiple-use forest management with the income from different types of agrarian systems. According to our calculations in this study, the mean annual economic benefits from multiple forest use are the same as the least productive agrarian system, but only 25% of the annual income generated by the most productive system. Although the income generated by logging may be considered low when calculated on an annual basis and compared to incomes generated by agriculture, the one-time payment after logging is significant (US$5,800 to US$33,508) and could be used to implement more intensive and productive cropping systems such as planting black pepper. The income from forest management could also be used to establish permanent fields in deforested areas for highly productive annual crops using conservation agriculture techniques. These techniques are alternatives to the traditional land use based on periodic clearing of the forest. Nevertheless, the shift in current practices towards adoption of more sustainable conservation agriculture techniques will also require the technical and legal support of the State to help small farmers apply these alternatives, which aim to integrate forest management in sustainable agricultural production systems.

Estudo comparativo entre MDF e MDP utilizados na indústria moveleira

Increasingly, the furniture market is competitive. The construction industry presents itself in growth, mainly due to the lines of existing incentives and tax credits established by the government, assisting the impulse to purchase real estate, building materials and furniture. Factors that promote and strengthen the sector's growth. With high demand from the furniture market, demand for higher quality and increasing technological advances, research is often undertaken in search of solutions for process improvement and product features, focusing on the production of materials less harmful to the environment, provision of raw press to lower cost, improve the production process and product development of cost-effective. This research focuses on the comparative study between two materials widely used in furniture manufacturing. MDF (Medium Density Fiberboard) and MDP (Medium Density Particleboard). The subject provides the focus in furniture production, presenting and comparing data collected from three companies producing panels between physical and mechanical characteristics of the materials, also presenting some of the main factors of influence on the quality of the panels, their features and applications on mobile. The study shows the high potential of using the MDP (Medium Density Particleboard) in furniture designs, as well as MDF (Medium Density Particleboard), favoring the final terms of the project , resulting in better utilization of each material , avoiding waste and increase unnecessary cost . Currently, several projects are developed in MDP and MDF furniture, where there is no relevance to their characteristics regarding their limitations. Many of these furnishings are designed without a specific study of the best use and positioning of each material, with better utilization , favoring collateral design , especially furniture designed exclusively for each environment . The lack of technical ...

Implantação da ISO 9001:2008: estudo de caso em empresado setor de construção civil

In Brazil , the construction industry is on an upward trend, mainly by the housing shortage , and yet there are few builders that take a Quality Management System ( QMS ) to improve the quality of its services and processes . The ISO 9001 standards are guidelines for an effective QMS and this certificate is recognized worldwide as a seal of quality standard. This paper will describe and analyze the implementation of a QMS in a small construction company of Guaratinguetá - SP, identifying best practices and major difficulties , besides proposing preparatory recommendations for other companies that seek the ISO 9000 certification. Access to company’s data made the nonconformities and the customer satisfaction research analysis possible, and a questionnaire and unstructured interviews allowed a deeper understanding of the situation. Despite this ISO 9000 QMS not being fully implemented, the company has already conquered some improvements in document control, project planning, process traceability and established focus on customer