Análise de ciclo avançado com seqüestro de carbono

The energy is considered one of the most important elements in the human´s life providing the survival as well as the well being. Nowadays, the technologies destined to generate power burn fossil fuels which pour gases (carbon dioxide among them) that contribute to the global warming phenomenon. Several research groups and universities have been studying different methods for generating power with low carbon dioxide emissions, including the possibility of burning zero-carbon fuels. In this text, it has been put attention to the Advanced Zero Emission Power Plants (AZEP) which separate the CO2 (from the gases involved in the power generation), compress it, dehydrate it and store it in appropriate reservoirs. The goal of this study was to find a possible solution to produce CO from CO2, activated by solar energy; the reaction between CO and steam generates a syngas comprised of H2 and CO2, which can be separated by chemical and/or physical processes. The text also contains a study concerning the compressed air energy storage power plant (CAES) and come up with its modification to C[CO2]ES. This power plant stores CO2 directing it to a reverse combustion process to produce CO which is headed to a syngas reactor to produce CO2 and H2. Hydrogen is separated and carried to the thermal cycle to generate power with low carbon emissions

Improving minimum quantity lubrication in CBN grinding using compressed air wheel cleaning

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

New concepts of the power received by ideal energy storage elements: the instantaneous complex power approach

This paper presents some definitions and concepts of the Instantaneous Complex Power Theory [1] which is a new approach for the Akagi's Instantaneous Reactive Power Theory [2].The powers received by an ideal inductor are interpreted and the knowledge of the actual nature of these powers may lead to changes of the conventional electrical power concepts.

Experimental and theoretical study of workpiece temperature when end milling hardened steels using (TiAl)N-coated and PcBN-tipped tools

The present work shows an experimental and theoretical study on heat flow when end milling, at high-speed, hardened steels applied to moulds and dies. AISI H13 and AISI D2 steels were machined with two types of ball nose end mills: coated with (TiAl)N and tipped with PcBN. The workpiece geometry was designed to simulate tool-workpiece interaction in real situations found in mould industries, in which complex surfaces and thin walls are commonly machined. The compressed and cold air cooling systems were compared to dry machining Results indicated a relatively small temperature variation, with higher range when machining AISI D2 with PcBN-tipped end mill. All cooling systems used demonstrated good capacity to remove heat from the machined surface, especially the cold air. Compressed air was the most indicated to keep workpiece at relatively stable temperature. A theoretical model was also proposed to estimate the energy transferred to the workpiece (Q) and the average convection coefficient ((h) over bar) for the cooling systems used. The model used a FEM simulation and a steepest decent method to find the best values for both variables. (c) 2007 Elsevier B.V. All rights reserved.

Background thermal depolarization of electrons in storage rings

We discuss the influence of the background thermal bath on the depolarization of electrons in high-energy storage rings, and on the photon emission associated with the spin flip. We focus, in particular, on electrons at CERN LEP. We show that in a certain interval of solid angles the photon emission is enhanced several orders of magnitude because of the presence of the thermal bath. Notwithstanding, the overall depolarization induced by the background thermal bath at LEP conditions is much smaller than the one induced by plain acceleration at zero temperature and can be neglected in practical situations. Eventually we discuss under what conditions the background thermal bath can enhance the overall depolarization by several orders of magnitude.

Estudo comparativo entre a lubri-refrigeração convencional e a MQL no processo de retificação cilíndrica externa de mergulho

Pós-graduação em Engenharia Mecânica - FEB

Eficiência energética aplicada na indústria de bebidas em sistemas de refrigeração e ar comprimido: estudo de casos

Pós-graduação em Engenharia Mecânica - FEG

Gestão energética nos setores transversais para redução do consumo de energia em uma empresa automobilística

Pós-graduação em Engenharia de Produção - FEG

Sensibilidade a herbicidas de acessos de aguapé coletados em reservatórios do Estado de São Paulo

Com o objetivo de avaliar o efeito de herbicidas em diferentes acessos de aguapé coletados em reservatórios de hidrelétricas do Estado de São Paulo, foi realizado um estudo no Núcleo de Pesquisas Avançadas em Matologia da FCA-UNESP, campus de Botucatu. A escolha das plantas geneticamente diferentes foi feita com base em estudos de variabilidade genética, nos quais se utilizou a técnica de RAPD. Avaliou-se o efeito dos herbicidas imazapyr nas doses de 62,5 e 125,0 g e.a. ha-1, glyphosate a 1.680 e 3.360 g e.a. ha-1 + 0,5% V/V de Extravon, diquat a 480 e 960 g i.a. ha-1 e 2,4-D a 670 e 1.340 g e.a. ha-1. Os seis acessos escolhidos foram colocados em caixas plásticas de 28,0 x 14,0 x 12,0 cm, contendo 4 litros de água. A aplicação dos produtos foi realizada com um simulador de pulverização pressurizado com ar comprimido, equipado com barra de aplicação com quatro bicos de jato plano Teejet 110.02 VS. A pressão constante de trabalho foi de 1,6 bar, e o consumo de calda, de 193 L ha-1. A velocidade de aplicação foi de 3,69 km h-1. Durante as aplicações, a temperatura do ar foi de 25 ºC e a umidade relativa de 73%. Foram realizadas avaliações visuais de controle aos 3, 5, 7, 11, 21 e 28 dias, nas quais 0 consistiu em nenhum controle e 100 em morte de plantas. Todos os herbicidas e doses testados proporcionaram controle eficiente das plantas de aguapé, e os seis acessos estudados responderam de forma semelhante.

Analysis of surface integrity for minimum quantity lubricant - MQL in grinding

The quality of machined components is currently of high interest, for the market demands mechanical components of increasingly high performance, not only from the standpoint of functionality but also from that of safety. Components produced through operations involving the removal of material display surface irregularities resulting not only from the action of the tool itself, but also from other factors that contribute to their superficial texture. This texture can exert a decisive influence on the application and performance of the machined component. This article analyzes the behavior of the minimum quantity lubricant (MQL) technique and compares it with the conventional cooling method. To this end, an optimized fluid application method was devised using a specially designed nozzle, by the authors, through which a minimum amount of oil is sprayed in a compressed air flow, thus meeting environmental requirements. This paper, therefore, explores and discusses the concept of the MQL in the grinding process. The performance of the MQL technique in the grinding process was evaluated based on an analysis of the surface integrity (roughness, residual stress, microstructure and microhardness). The results presented here are expected to lead to technological and ecological gains in the grinding process using MQL. (c) 2006 Elsevier Ltd. All rights reserved.

Analysis of the Influence of Sparkout Time on Grinding Using Several Lubrication/Cooling Methods

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Limpeza da superfície de corte de rebolos por um sistema de ar comprimido na retificação cilíndrica externa de mergulho de materiais cerâmicos refrigerados com a técnica da mínima quantidade de lubrificante (MQL)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Application of the Minimum Quantity Lubrication (MQL) Technique in the Plunge Cylindrical Grinding Operation

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Materiais cerâmicos de inserção aplicados a baterias de íons lítio

Esta revisão visa ser uma introdução à aplicação de materiais cerâmicos em dispositivos de armazenamento de energia, em especial baterias secundárias de íons lítio, dispositivos nos quais os materiais cerâmicos, especialmente óxidos, são muito importantes em todas as partes do dispositivo. A revisão está focada nos materiais cerâmicos para catodos e anodos, partes chaves destes dispositivos. Ela tem por principal finalidade ser uma fonte de informação para aqueles que desejem trabalhar com o desenvolvimento de materiais cerâmicos para tais tipos de dispositivos. Aspectos relacionados à nanotecnologia e materiais óxidos nanoestruturados para esta área são discutidos ao final do artigo.

Corrosion and Wear Studies of Cr3C2NiCr-HVOF Coatings Sprayed on AA7050 T7 Under Cooling

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)