Análise térmica e mecânica de um compósito de matriz cerâmica com carga de EPS e raspa de pneu para construção de casas populares

Space Science was built using a composite made of plaster, EPS, shredded tires, cement and water. Studies were conducted to thermal and mechanical resistance. Inside the mold EPS plates were placed in order to obtain a higher thermal resistance on the wall constructed, as well as to give it an end environmentally friendly in view of both the tire and the EPS occupy a large space in landfills and year need to be degraded when released into the environment. Compression tests were performed according to ABNT blocks to seal, measurements of the temperature variation in the external and internal walls using a laser thermometer and check the temperature of the indoor environment using a thermocouple attached to a digital thermometer. The experiments demonstrated the heat provided by the composite values from the temperature difference between the internal and external surfaces on the walls, reaching levels of 12.4 ° C and room temperature in the interior space of the Science of 33.3 ° C, remaining within the zone thermal comfort for hot climate countries. It was also demonstrated the proper mechanical strength of such a composite for sealing walls. The proposed use of the composite can contribute to reducing the extreme housing shortage in our country, producing popular homes at low cost and with little time to work

Estudo de um isolante térmico para tubos fabricado em material compósito

It presents a new type of insulation for ductwork hot water, which can be used in solar systems for heating water, which consists of a composite of different compositions based on plaster, cement and EPS ground, palm and water. This composite has as its main features easy assembly and manufacturing processes and low cost. Comparative results will be presented on the tests of materials and thermal tubes proposed. Four formulations were used to manufacture tubes with three diameters 70, 65 and 42mm. It was also tested conventionally used for elastomeric foam insulation to 110 ° C, for a comparative analysis with the composite pipe insulator proposed. It will demonstrate that the cost of manufacturing of such tubes is competitive with alternative elastomeric foam tested, but results of the composite tube to the temperature range studied, are lower. Another drawback of the composite insulator tube is its large mass. It would be important to test such a composite for greater levels of temperature to a diagnostic technique competitive with conventionally used insulators. A positive factor of using the proposed composite-tube would be the recycling of EPS so damaging to the environment, representing an environmentally friendly application of science

Estudo tribológico de biolubrificantes com adição de nanopartículas de óxidos (zinco e cobre)

Currently, vegetable oils have been studied for bio-lubricants base that fits the new environmental standards. Since, in a world full of finite natural resources, mineral oils bring consequences to the environment due to its low biodegradability and toxicity, also it is important to consider that synthetic oils have a high cost The aim of this work is to obtain a biolubricant additived with oxide nanoparticles (ZnO and CuO) for better resistance to friction and wear, which is not toxic to the environment and have better adherence under boundary lubrication. The methodology consisted in the synthesis of bio-lubricants (soybean and sunflower base) by epoxidation reaction. Then, some physical-chemical analysis in bio-lubricants are made to characterize theses lubricants, such as, density, acidity, iodine value, viscosity, viscosity index. Later, the lubricants were additive with nanoparticles. The tribological performance was evaluated by the equipment HFRR (High Frequency Reciprocating Rig) consisting of a wear test ball-plan type. The characterization of wear analysis was performed by SEM / EDS. The results show that bio-lubricants may be synthesized by reaction of epoxidation with good conversion. Tribological point of view, the epoxidized oils are more effective than lubricant additived with the oxide nanoparticles, they had lower coefficients of friction and better rate of film formation in the study. However, because they are environmentally friendly, bio-lubricants gain the relevant importance in tribological field

Desenho e Construção de um protótipo gerador de jato de plasma frio a pressão atmosférica para aplicações biomédicas

Research for better performance materials in biomedical applications are constants. Thus recent studies aimed at the development of new techniques for modification of surfaces. The low pressure plasma has been highlighted for its versatility and for being environmentally friendly, achieving good results in the modification of physic chemical properties of materials. However, it is requires an expensive vacuum system and cannot able to generate superficial changes in specific regions. Furthermore, it is limits their use in polymeric materials and sensitive terms due to high process temperatures. Therefore, new techniques capable of generating cold plasma at atmospheric pressure (APPJ) were created. In order to perform surface treatments on biomaterials in specific regions was built a prototype capable of generating a cold plasma jet. The prototype plasma generator consists of a high voltage source, a support arm, sample port and a nozzle through which the ionized argon. The device was formed to a dielectric tube and two electrodes. This work was varied some parameters such as position between electrodes, voltage and electrical frequency to verify the behavior of glow discharges. The disc of titanium was polished and there was a surface modification. The power consumed, length, intensity and surface modifications of titanium were analyzed. The energy consumed during the discharges was observed by the Lissajous figure method. To check the length of the jets was realized with Image Pro Plus software. The modifications of the titanium surfaces were observed by optical microscopy (OM ) and atomic force microscopy (AFM ). The study showed that variations of the parameters such as voltage, frequency and geometric position between the electrodes influence the formation of the plasma jet. It was concluded that the plasma jet near room temperature and atmospheric pressure was able to cause modifications in titanium surface

Modelagem da transferência de massa na remoção do óleo da água produzida por flotação em coluna com uso de tensoativos de origem vegetal

The treatment of oil produced water and its implications are continually under investigation and several questions are related to this subject. In the Northeast Region Brazil, the onshore reservoirs are, in its majority, mature oil fields with high production of water. As this oil produced water has high levels of oil, it cannot be directly discarded into the environment because it represents a risk for contamination of soil, water, and groundwater, or even may cause harm to living bodies. Currently, polyelectrolytes that promote the coalescence of the oil droplets are used to remove the dispersed oil phase, enhancing the effectiveness of the flotation process. The non-biodegradability and high cost of polyelectrolytes are limiting factors for its application. On this context, it is necessary to develop studies for the search of more environmentally friendly products to apply in the flotation process. In this work it is proposed the modeling of the flotation process, in a glass column, using surfactants derived from vegetal oils to replace the polyelectrolytes, as well as to obtain a model that represents the experimental data. In addition, it was made a comparative study between the models described in the literature and the one developed in this research. The obtained results showed that the developed model presented high correlation coefficients when fitting the experimental data (R2 > 0.98), thus proving its efficiency in modeling the experimental data.

In the eye of the storm: exploring the introduction of environmental issues in the production function in Brazilian companies

This article aims to analyse the introduction of environmental issues in the context of the production function, which has been referred to as the organisational area to lead corporate environmental management. With that purpose, the theoretical references for corporate environmental management and the necessary alterations in production function have been organised to include environmental aspects, especially in terms of product and process development, quality management, and logistics. Considering that this research field still lacks empirical evidence for Brazilian companies, four case studies were conducted using companies located in the country. The environmental management maturity level of those companies tends to follow the rate with which the environmental issue is introduced in production sub-areas, especially in the product development process. However, in most cases we found that the companies had difficulties in structuring the insertion of the environmental dimension in logistics. The final notes point out the distance observed between what is recommended by international literature and the reality of Brazilian companies in the challenge of making the production function environmentally friendly.

Physical-chemical and thermodynamic analyses of ethanol steam reforming for hydrogen production

Steam reforming is the most usual method of hydrogen production due to its high production efficiency and technological maturity the use of ethanol for this purpose is an interesting option because it is a renewable and environmentally friendly fuel. The objective of this article is to present the physical-chemical, thermodynamic, and exergetic analysis of a steam reformer of ethanol, in order to produce 0.7 Nm(3)/h of hydrogen as feedstock of a 1 kW PEMFC the global reaction of ethanol is considered. Superheated ethanol reacts with steam at high temperatures producing hydrogen and carbon dioxide, depending strongly on the thermodynamic conditions of reforming, as well as on the technical features of the reformer system and catalysts. The thermodynamic analysis shows the feasibility of this reaction in temperatures about 206 degrees C. Below this temperature, the reaction trends to the reactants. The advance degree increases with temperature and decreases with pressure. Optimal temperatures range between 600 and 700 degrees C. However, when the temperature attains 700 degrees C, the reaction stability occurs, that is, the hydrogen production attains the limit. For temperatures above 700 degrees C, the heat use is very high, involving high costs of production due to the higher volume of fuel or electricity used. The optimal pressure is 1 atm., e.g., at atmospheric pressure. The exergetic analysis shows that the lower irreversibility is attained for lower pressures. However the temperature changes do not affect significantly the irreversibilities. This analysis shows that the best thermodynamic conditions for steam reforming of ethanol are the same conditions suggested in the physical-chemical analysis.

Avaliação da estabilidade térmica e oxidativa dos biodieseis de algodão, girassol, dendê e sebo bovino

The search for new sources of environmentally friendly energy is growing every day. Among these alternative energies, biodiesel is a biofuel that has had prominence in world production. In Brazil, law 11.097, determine that all diesel sold in the country must be made by mixing diesel/biodiesel. The latter called BX, , where X represents the percent volume of biodiesel in the diesel oil, as specified by the ANP. In order to guarantee the quality of biodiesel and its mixtures, the main properties which should be controlled are the thermal and oxidative stability. These properties depend mainly of the chemical composition on the raw materials used to prepare the biodiesel. This dissertation aims to study the overall thermal and oxidative stability of biodiesel derived from cotton seed oil, sunflower oil, palm oil and beef tallow, as well as analyze the properties of the blends made from mineral oil and biodiesel in proportion B10. The main physical-chemical properties of oils and animal fat, their respective B100 and blends were determined. The samples were characterized by infrared and gas chromatography (GC). The study of thermal and oxidative stability were performed by thermogravimetry (TG), pressure differential scanning calorimeter (PDSC) and Rancimat. The obtained biodiesel samples are within the specifications established by ANP Resolution number 7/2008. In addition, all the blends and mineral diesel analyzed presented in conformed withthe ANP Regularion specifications number 15/2006. The obtained results from TG curves data indicated that the cotton biodiesel is the more stable combustible. In the kinetic study, we obtained the following order of apparent activation energy for the samples: biodiesel from palm oil > sunflower biodiesel > tallow biodiesel > cotton biodiesel. In terms of the oxidative stability, the two methods studied showed that biodiesel from palm oil is more stable then the tallow. Within the B100 samples studied only the latter were tound to be within the standard required by ANP resolution N° 7. Testing was carried out according to the EN14112. This higher stability its chemical composition

Estudo da eficácia do tensoativo sorbitano tween 80 veiculado em nanoemulsão contendo óleo de soja, como inibidor de corrosão

Nowadays, the use of chemicals that satisfactorily meet the needs of different sectors of the chemical industry is linked to the consumption of biodegradable materials. In this context, this work contemplated biotechnological aspects with the objective of developing a more environmentally-friendly corrosion inhibitor. In order to achieve this goal, nanoemulsion-type systems (NE) were obtained by varying the amount of Tween 80 (9 to 85 ppm) a sortitan surfactant named polyoxyethylene (20) monooleate. This NE-system was analyzed using phase diagrams in which the percentage of the oil phase (commercial soybean oil, codenamed as OS) was kept constant. By changing the amount of Tween 80, several polar NE-OS derived systems (O/W-type nanoemulsion) were obtained and characterized through light scattering, conductivity and pH, and further subjected to electrochemical studies. The interfacial behavior of these NE-OS derived systems (codenamed NE-OS1, S2, S3, S4 and S5) as corrosion inhibitors on carbon steel AISI 1020 in saline media (NaCl 3.5%) were evaluated by measurement of Open Circuit Potential (OCP), Polarization Curves (Tafel extrapolation method) and Electrochemical Impedance Spectroscopy (EIS). The analyzed NE-OS1 and NE-OS2 systems were found to be mixed inhibitors with quantitative efficacy (98.6% - 99.7%) for concentrations of Tween 80 ranging between 9 and 85 ppm. According to the EIS technique, maximum corrosion efficiency was observed for some tested NE-OS samples. Additionaly to the electrochemical studies, Analysis of Variance (ANOVA) and Principal Component Analysis (PCA) were used, characterization of the nanoemulsion tested systems and adsorption studies, respectively, which confirmed the results observed in the experimental analyses using diluted NE-OS samples in lower concentrations of Tween 80 (0.5 1.75 ppm)

A simple and green analytical method for determination of glyphosate in commercial formulations and water by diffuse reflectance spectroscopy

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Determination of nitrite in meat products and water using dapsone with combined spot test/diffuse reflectance on filter paper

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Cobalt phthalocyanine as a biomimetic catalyst in the amperometric quantification of dipyrone using FIA

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

Desenvolvimento de um método reflectométrico ambientalmente mais amigável para a determinação de metoclopramida em formulações farmacêuticas

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

Preparation, structural and optical characterization of BaWO4 and PbWO4 thin films prepared by a chemical route

Polycrystalline BaWO4 and PbWO4 thin films having a tetragonal scheelite structure were prepared at different temperatures. Soluble precursors such as barium carbonate, lead acetate trihydrate and tungstic acid, as starting materials, were mixed in aqueous solution. The thin films were deposited on silicon, platinum-coated silicon and quartz substrates by means of the spinning technique. The surface morphology and crystal structure of the thin films were investigated using scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray diffraction, and specular reflectance infrared Fourier transform spectroscopy, respectively. Nucleation stages and surface morphology evolution of thin films on silicon substrates have been studied by atomic force microscopy. XRD characterization of these films showed that BaWO4 and PbWO4 phase crystallize at 500 degreesC from an inorganic amorphous phase. FTIR spectra revealed the complete decomposition of the organic ligands at 500 degreesC and the appearance of two sharp and intense bands between 1000 and 600 cm(-1) assigned to vibrations of the antisymmetric stretches resulting from the high crystallinity of both thin films. The optical properties were also studied. It was found that BaWO4 and PbWO4 thin films have Eg = 5.78 eV and 4.20 eV, respectively, of a direct transition nature. The excellent microstructural quality and chemical homogeneity results confirmed that soft solution processing provides an inexpensive and environmentally friendly route for the preparation of BaWO4 and PbWO4 thin films. (C) 2003 Elsevier Ltd. All rights reserved.

Electroluminescence of zinc oxide thin-films prepared via polymeric precursor and via sol-gel methods

Zinc oxide (ZnO) is an electroluminescent (EL) material that can emit light in different regions of electromagnetic spectrum when electrically excited. Since ZnO is chemically stable, inexpensive and environmentally friendly material, its EL property can be useful to construct solid-state lamps for illumination or as UV emitter. We present here two wet chemical methods to prepare ZnO thin-films: the Pechini method and the sol-gel method, with both methods resulting in crystalline and transparent films with transmittance > 85% at 550 nm. These films were used to make thin-film electroluminescent devices (TFELD) using two different insulator layers: lithium fluoride (LiF) or silica (SiO2). All the devices exhibit at least two wide emission bands in the visible range centered at 420 nm and at 380 nm attributed to the electronic defects in the ZnO optical band gap. Besides these two bands, the device using SiO2 and ZnO film obtained via sol-gel exhibits an additional band in the UV range centered at 350 nm which can be attributed to excitonic emission. These emission bands of ZnO can transfer their energy when a proper dopant is present. For the devices produced the voltage-current characteristics were measured in a specific range of applied voltage. (C) 2007 Elsevier B.V. All rights reserved.