Análise estatística das emissões de CO e HC produzidas por gases da exaustão veicular oriundos de gasolina, GNV e mistura álcool/gasolina

The vehicles are the main mobile sources of carbon monoxide (CO) and unburned hydrocarbons (HC) released into the atmosphere. In the last years the increment of the fleet of vehicles in the municipal district of Natal-RN it is contributing to the increase of the emissions of those pollutants. The study consisted of a statistical analysis of the emissions of CO and HC of a composed sample for 384 vehicles with mechanization Gasoline/CNG or Alcohol/Gasoline/CNG of the municipal district of Natal-RN. The tests were accomplished in vehicles submitted to Vehicular Safety's Inspection, in the facilities of INSPETRANS, Organism of Vehicular Inspection. An partial gases analyzer allowed to measure, for each vehicle, the levels of CO and HC in two conditions of rotation of the motor (900 and 2500 rpm). The statistical analysis accomplished through the STATISTICA software revealed a sensitive reduction in the efficiency of the converters catalytic after 6 years of use with emission average it is of 0,78% of CO and 156 (ppm) of HC, Which represents approximately 4 (four) times the amount of CO and the double of HC in comparison with the newest vehicles. The result of a Student s t-test, suggests strongly that the average of the emissions of HC (152 ppm), at 900 rpm, is 40% larger than at 2500 rpm, for the motor without load. This result reveals that the efficiency of the catalytic conversion is limited kinetically in low engine speeds. The Study also ends that when comparing the emissions of CO and HC considering the influence of the fuels, it was verified that although the emissions of CO starting from CNG are 62% smaller than arising from the gasoline, there are not significant differences among the emissions of HC originating from of CNG and of the gasoline. In synthesis, the results place the current criteria of vehicular inspection, for exhaust gases, in doubt, leading the creation of emission limits of pollutant more rigorous, because the efficiency of the converters catalytic is sensibly reduced starting from 6 years of use. It is also raised the possibility of modifications in the test conditions adopted by the current norms, specifically in the speed engine, have seen that in the condition without load the largest emission indexes were registered in slow march. That fact that allows to suggest the dismissal of the tests in high speed engine, reducing the time of inspection in half and generating economy of fuel

Formulação e caracterização de massas de grês porcelanato preparadas a partir de matérias-primas naturais do Rio Grande do norte e com adição de chamote de telhas

Traditional ceramics have an important role in the economy of Rio Grande do Norte. The local industries manufacture over 50 million shingles a month, corresponding to 60% of their overall production. As a result of processing flaws, roughly 20% of the production must be discarded, since little or no use has been envisaged for such fired components. Therefore, the use of this kind of residue, especially in the composition of other ceramic materials, comes as an interesting option from the economical and environmental point of view. In this scenario, the objective of the present study was to assess the effect of the addition of fired shingle waste in the composition of porcelainized stoneware tiles. To that end, two porcelainized stoneware tiles compositions were initially prepared. Subsequently, contents from 10 to 30% of roofing tiles chamote were added to each one of them. All raw materials and grog were characterized by FRX, XRD, and thermal analysis. The ceramics were fired using natural gas for 30 min at different temperatures, i.e. 1150, 1200 and 1250ºC, and fully characterized. The addition of roofing tiles chamote resulted in composition with superior properties compared to additive-free compositions. Porcelainized stoneware tiles products that fulfill required standards for practical applications were achieved

Avaliação do processo industrial da cerâmica vermelha na região do Seridó - RN

Particularly in Braziland in Rio Grande do Norte, companies manufacturing red ceramic, play an important role as agents of development to study the region Seridó- RN, specific place for carrying out the research. It is observed in this region a concentration of red ceramic industries of small size, which, despite its importance in the ceramic, they are unable to enjoy or use the new forms of administrative management and technological advances designed and offered by universities, centers of research and projects of governments, remained almost entirely outside the progress and modernization, technological and administrative. These companies still have outdated technology, and management processes, providing quality problems and standardization of end products. Upon these conditions are the companies going through crisis and struggling to survive alone and without assistance. The region of Seridó-RN, lets make a detailed case study of red ceramic companies in the region proposed from the existing theoretical and actual lifting of the condition of the product manufacturing red ceramic, allowing through this overview of the implementation of collect samples of raw materials, allowing the study of each ceramic industry that contributed to the participation of the research, which was determined parameters such as: analysis of the physical, chemical and technological properties of raw materials, characterization of the processes used, raising the technological resources considering equipment, machinery, supplies, raw materials and facilities available and its organization by type of products from companies involved in this study. The methodology consists of the following steps: collection of raw material, crushing and screening, characterization of raw materials (liquid limit, chemical analysis, mineralogical analysis, differential thermal analysis, sieve analysis), mixing, forming, cutting, drying and burning of ceramic bodies and bodies of evidence. The results showed that it was clay with distinct characteristics with respect to plasticity. With respect to the different compositions of mixtures of ceramic masses, we conclude that the ceramic properties showed a direct proportionality with increasing fraction of the clay not plastic. However, the compositions of the masses studied proved to be the most appropriate for the types of simulated clay for use in ceramics. Adopted in the ceramic processing made it possible to obtain products the resulted in consistent properties, and in some cases even exceeding the requirements of technical studies and standard-Brazilian clays to obtain ceramic products such as tiles, bricks and tiles to floor. Based on the discussions from the results obtained in the various processing steps of this work, one can draw conclusions according to the physico-chemical and mineralogical properties of raw materials, the properties of ceramic products burned and analysis. This work may be used by other researchers, private companies and governmental organizations, undergraduate students and graduate, can develop studies and future research to: develop projects to modify the furnaces; mapping projects develop and rationalize the exploitation of raw materials ;promoting reforestation and forest management; develop reduction projects and recovery of waste; develop training projects in manpower sector, and develop security projects, improving the conditions of work in the area pottery

Desempenho de um veículo flex em bancada dinamométrica de chassi

Flex-fuel vehicles are equipped with Otto Cycle internal combustion engines and have the capability of functioning with more than one type of fuel, mixed at the same tank and burned in the combustion chamber simultaneously. This sort of motorization is a world pattern due to the scarcity of petroleum, the trade of several types of fuels, technology advances and the restriction imposed to gas emissions to the atmosphere. In Brazil, the Flexfuel vehicles are a reality, specially the ones using fuel with 20 to 25% anhydrous alcohol mixed with gasoline and those that use natural gas or original liquid fuel (gasoline or hydrated ethanol). The Brazilian model Fiat Siena, the object of this present scientific investigation, is equipped with a unique electronic central capable of managing the liquid or gaseous fuels. The purpose of this research was to perform a comparative analysis in terms of performance (in terms of both potency and consumption) of a tetra-fuel vehicle - using a chassis dynamometer, operating with different fuels: common gasoline, premium gasoline, Podium gasoline, ethanol or natural gas. It became necessary to develop a bench of tests and trials procedures, as well as to know the functioning of the electronic management of the vehicle under analysis. The experiments were performed at the automotive laboratory in CTGAS-ER (Center of Gas Technologies and Renewable energies) at the light of Brazilian standard ABNT, NBR 7024: Light on-road vehicles - measurement of fuel consumption. The essay results on specific fuel consumption using common gasoline, premium gasoline and Podium gasoline have shown similar results, both for urban and road driving cycles

Análise de desempenho de um fogão solar construído a partir de sucatas de antena de tv

Given the growing environmental crisis caused by degradation, mainly due to the use of polluting energy sources, increasing the growing use of renewable energies worldwide, with emphasis on solar energy, an abundant supply and available to everyone, which can be harnessed in several ways: electricity generation; dehydration of food; heating, disinfection and distillation and cooking. The latter has as its primary feature the viability of clean, renewable energy for society, combating ecological damage caused by large-scale use of firewood for cooking foods, use in tropical countries with high solar radiation, and has funding NGOs throughout the world with the goal of achieving low-income population. The proposed project consists of a solar cooker for concentration, working from the reflection of sunlight by a hub that they converge to a focal point at the bottom of the pot, getting lots of heat. The solar cooker under study consists of two elliptical reflecting parabolas made from the recycling of scrap TV antenna, having 0.29 m² of surface area for each antenna, which were covered by multiple mirrors of 2 mm thick and mounted on a metal structure, with correction for the mobility of the apparent movement of the sun. This structure was built with the recycling of scrap metal, possessing a relatively low cost compared with other solar cookers, around US$ 50.00. This cost becomes negligible, since that will involve a great benefit to not have fuel costs for each meal, unlike the use of gas or firewood for cooking food. The tests show that the cooker has reached the maximum temperature of 740 ° C, for boiling water in an average time of 28 minutes, cooking various types of foods such as potatoes, rice and pasta in an average time of 45 minutes and still going as a solar oven, making pizza baking and meat. These cooking times do not differ much from the cooking times on a gas stove, it becomes the solar cooker as a good consumer acceptance, and furthermore not to deliver the same gases that can poison the food as with the wood stove. Proves the viability of using the stove to cook or bake in two daily meals for a family, still presenting a position to improve his performance with the addition of new materials, equipment and techniques

Atributos químicos do solo, crescimento radicular e produtividade do arroz de acordo com a aplicação de escórias

Resíduos industriais são fontes alternativas de nutrientes para as plantas e sua utilização decorre da necessidade de diminuir o acúmulo dos resíduos nos centros de produção. O objetivo deste trabalho foi avaliar o efeito de escórias de siderurgia nos atributos químicos do solo, no desenvolvimento e na produtividade de grãos do arroz de terras altas irrigado por aspersão. O delineamento experimental foi em blocos casualizados, com três tratamentos constituídos de duas escórias, alto-forno (196 g kg-1 de Si) e aciaria (56 g kg-1 de Si), e a testemunha sem aplicação, com oito repetições. As escórias podem ser usadas como corretivo de acidez do solo e como fonte de silício. As alterações nos atributos químicos do solo estão relacionadas com a composição química das escórias. A escória de alto-forno proporcionou maior crescimento radicular em profundidade e melhor distribuição no perfil do solo e, conseqüentemente, maior produção de massa de matéria seca da parte aérea e produtividade de grãos de arroz.

Redução carbotérmica de TiO2 por descarga em cátodo oco

In this study we used the plasma as a source of energy in the process of carbothermic reduction of rutile ore (TiO2). The rutile and graphite powders were milled for 15 h and placed in a hollow cathode discharge produced by in order to obtain titanium carbonitride directly from the reaction, was verified the influence of processing parameters of plasma temperature and time in the synthesis of TiCN. The reaction was carried out at 600, 700 and 800˚C for 3 to 4 hours in an atmosphere of nitrogen and argon. During all reactions was monitored by plasma technique of optical emission spectroscopy (EEO) to check the active species present in the process of carbothermal reduction of TiO2. The powder obtained after the reactions were characterized by the techniques of X-ray diffraction (XRD) and scanning electron microscopy (SEM). The technique of EEO were detected in all reactions the spectra CO and NO, and these gas-phase resulting from the reduction of TiO2. The results of X-ray diffraction confirmed the reduction, where for all conditions studied there was evidence of early reduction of TiO2 through the emergence of intermediate oxides. In the samples reduced at 600 and 700˚C, there was only the phase Ti6O11, those reduced to 800˚C appeared Ti5O9 phases, and Ti6O11 Ti7O13, confirming that the carbothermal reduction in plasma, a reduction of the ore rutile (TiO2) in a series of intermediate titanium oxide (TinO2n-1) where n varies between 5 and 10

Estudo da fibra de coco como reforço em tijolo de solocimento

To take care of to the demand of the new constructions in the low income communities and to develop the production of a strengthened alternative brick with staple fibers of coconut, capable to contribute mainly with the recycling of the green and mature coconut in the urban and agricultural lexes, this research was developed, to confection bricks of soil-cement with coconut fiber. Ecologically correct material and of low cost, since the greenhouse use of or oven for burning will be manufactured without. The study it presents a set of tables and graphs that prove good indices found in the values of the density, water absorption, axial compressive strength and isolation term acoustics, with evidential results that make possible the production in industrial character with press mechanics or the place of the workmanship with manual form. The preparation of coconut staple fibers was made of natural form without use of chemical products not to deprive of characteristics the properties mechanical physicist-chemistries and of the same ones. The sixty bricks produced in simple and manual press had been carried through in four lots of fifteen units. The mixture of aggregates was made in four different traces composites for: ground erinaceous, cement, fiber of dry coconut and water; the bricks had been compact in the press and cured in natural way under an area covered during the minimum time of seven days

Desenvolvimento e teste de um protótipo de reator de plasma com gaiola catódica rotatória para nitretação em lote de pequenas peças

The technique of ion nitriding, despite being fully consolidated in the industry, has great limitations when applied to the treatment of small parts. This is because effects that occur due to non-uniformity of the electric field, generate localized heating in parts, damaging the uniformity of nitrided layer. In addition, because the samples are treated static parts thereof are untreated. To expand the use of plasma nitriding, this work presents the development, assembly and testing of a prototype plasma reactor with rotatory cathodic cage [patent pending], able to meet these needs, giving the material a uniform treatment and opening doors to industrial scale production. The samples tested with hexagonal nuts are 6.0 mm in diameter, made of stainless steel AISI 304 nitrided at a pressure of 1 mbar in an atmosphere of 20% H2 + 80% N2 for 1 h. After treatment, testing visual inspection, optical microscopy and microhardness were carried out to check the effectiveness of the process for uniformity and hardness of the parts. All samples exhibited uniform color, and matte brownish, unlike the untreated samples, silver color and gloss. The hardness of the surface (top and sides) was 65% and even higher than the original hardness. The nitrided layer showed great uniformity in microstructure and thickness. It is concluded, therefore, that the unit was effective constructed for the purposes for which it was designed

Medida indireta de temperatura de corpos imersos em plasma

O gradiente térmico da superfície para o interior do sólido depende da taxa de colisões das partículas e da condutividade térmica do material utilizado. Quando um sólido é imerso em plasma, a transferência de energia ocorre por radiação e colisões das partículas sobre a superfície do material. Dependendo da taxa de colisões das particulas e da condutividade térmica do sólido existirão gradientes térmicos da superfície para o interior das amostras, ocorrendo picos térmicos na superficie, ou seja, o aquecimento pontual nas regiões de colisões. A fim de estudar esse efeito, amostras de aço rápido AISI M35 cujos valores de dureza são fortemente sensíveis à temperatura de revenimento, foram utilizadas como micro sensores térmicos. Amostras foram temperadas em forno resistivo e, em seguida, parte das mesmas foram revenidas em forno resistivo e a outra parte em plasma. A partir do gráfico da dureza (Hv) em função da temperatura (T) das amostras revenidas em forno resistivo foi possível obter uma função Hv(T) para determinação indireta do perfil térmico das amostras tratadas em plasma. As amostras foram revenidas em plasma utilizando temperatura de referência igual a 550 oC. Em seguida foi obtido o perfil de dureza dessas amostras ao longo da seção transversal e, subsequentemente, o perfil de temperatura. Verificou-se que amostras tratadas em plasma, ao contrário daquelas tratadas em forno resistivo, apresentaram gradiente de temperatura da superfície para o núcleo. Além disso, verificou-se que as amostras tratadas em configuração planar apresentaram gradientes térmicos inferiores àquelas tratadas em configuração cátodo oco, variando de 20 a 120 °C, respectivamente

Modificação superficial do tecido de malha de ácido polilatico (PLA) por tratamento plasma

Some fibrous materials, for having properties such as biocompatibility, strength and flexibility, are of great interest for medical and pharmaceutical applications. Among these materials, the fabric made from polylactic acid (PLA) has received special attention, and beside to present these features, is derived from biological source, antimicrobial and bioabsorbable. One of the limitations of PLA is its low wettability and capillarity. Due to this, it is necessary to perform surface modification of the knitted fabric, increasing its hydrophilicity. This work aims to realize the plasma treatment at low pressure in order to increase the surface energy of the polymer. The work was divided into three steps: i) Influence of the gas ratio (oxygen and nitrogen) in the surface modification of PLA fabric after the plasma treatment, ii) physical characterization and physicochemical surface tissue; iii) Evaluation of the effect from current and gas ratio in the capillary rise of tissues and iv) Study of capillarity in yarns and fabrics. The results showed that better gas ratios were the atmospheres: 100% oxygen; 100% nitrogen and 50% oxygen and 50% nitrogen. The surface characterization showed changes in topography and introduction of polar groups which increased the wettability of the fabric. In another part of this study, it was found that the atmosphere containing only nitrogen gas showed the most capillary rise to a current of 0.15 A. The results in capillary yarns and fabrics showed that the thread reached equilibrium in a time much less than the fabric to an atmosphere of 100% nitrogen and 0.15 A. Current Plasma technology was effective to increase the hydrophilicity of PLA fabric, providing surface characteristics favorable for future application in the biomedical field

Construção e avaliação térmica de um fogão solar tipo caixa

The present work presents a contribution in the study of modelings of transference of heat for foods submitted to the experimental tests in the considered solar oven, where the best modeling for the beefburger of chicken in study was evaluated, comparing the results, considering this food as a half-infinite(1er object considered model) and,after that, considered the chicken beefburger as a plain plate in transient regimen in two distinct conditions: not considering and another model considering the contribution of the generation term, through the Criterion of Pomerantsev. The Sun, beyond life source, is the origin of all the energy forms that the man comes using during its history and can be the reply for the question of the energy supplying in the future, a time that learns to use to advantage in rational way the light that this star constantly special tax on our planet. Shining more than the 5 billion years, it is calculated that the Sun still in them will privilege for others 6 billion years, or either, it is only in the half of its existence and will launch on the Earth, only in this year, 4000 times more energy that we will consume. Front to this reality, would be irrational not to search, by all means technical possible, to use to advantage this clean, ecological and gratuitous power plant. In this dissertation evaluate the performance of solar cooker of the type box. Laboratory of Solar Energy of the Federal University of the Great River of North - UFRN was constructed by the group (LES) a model of solar stove of the type box and was tested its viability technique, considering modeling foods submitted when baking in the solar oven, the cooker has main characteristic the easiness of manufacture and assembly, the low cost (was used material accessible composition to the low income communities) and simplicity in the mechanism of movement of the archetype for incidence of the direct solar light. They had been proposals modeling for calculations of food the minimum baking time, considering the following models of transference of heat in the transient state: object the halfinfinite, plain plate and the model of the sphere to study the necessary temperature for the it bakes of bread (considering spherical geometry). After evaluate the models of transmission of heat will be foods submitted you the processes of to it bakes of, the times gotten for the modeling with the experimental times of it bakes in the solar oven had been compared, demonstrating the modeling that more good that it portraies the accuracies of the results of the model

Tratamento de materiais contaminados com bifenilas policloradas (PCBS) via extração convencional e fluído supercrítico

The decontamination of the materials has been subject of some studies. One of the factors that it increases the pollution is the lack of responsibility in the discarding of toxic trash, as for example the presence of PCB (Polychlorinated Biphenyls) in the environment. In the Brazilian regulations, the material contaminated with PCB in concentrations higher than 50 ppm must be stored in special places or destroyed, usually by incineration in plasma furnace with dual steps. Due to high cost of the procedure, new methodologies of PCBs removal has been studied. The objective of this study was to develop an experimental methodology and analytical methodology for quantification of removal of PCBs through out the processes of extractions using supercritical fluid and Soxhlet method, also technical efficiency of the two processes of extraction, in the treatment of contaminated materials with PCBs. The materials studied were soils and wood, both were simulated contamination with concentration of 6.000, 33.000 and 60.000 mg of PCB/ kg of materials. Soxhlet extractions were performed using 100 ml of hexane, and temperature of 180 ºC. Extractions by fluid supercritical were performed at conditions of 200 bar, 70°C, and supercritical CO2 flow-rate of 3 g/min for 1-3 hours. The extracts obtained were quantified using Gas chromatography-mass spectrometry (GC/MS). The conventional extractions were made according to factorial experimental planning technique 22, with aim of study the influence of two variables of process extraction for the Soxhlet method: contaminant concentration and extraction time for obtain a maximum removal of PCB in the materials. The extractions for Soxhlet method were efficient for extraction of PCBs in soil and wood in both solvent studied (hexane and ethanol). In the experimental extraction in soils, the better efficient of removal of PCBs using ethanol as solvent was 81.3% than 95% for the extraction using hexane as solvent, for equal time of extraction. The results of the extraction with wood showed statistically it that there is not difference between the extractions in both solvent studied. The supercritical fluid extraction in the conditions studied showed better efficiency in the extraction of PCBs in the wood matrix than in soil, for two hours extractions the obtain percentual of 43.9 ± 0.5 % for the total of PCBs extracted in the soils against 95.1 ± 0,5% for the total of PCBs extracted in the wood. The results demonstrated that the extractions were satisfactory for both technical studied

Desenvolvimento de uma unidade laboratorial para quantificação de BTX como poluentes atmosféricos, usando microextração em fase sólida

This dissertation aims the development of an experimental device to determine quantitatively the content of benzene, toluene and xylenes (BTX) in the atmosphere. BTX are extremely volatile solvents, and therefore play an important role in atmospheric chemistry, being precursors in the tropospheric ozone formation. In this work a BTX new standard gas was produced in nitrogen for stagnant systems. The aim of this dissertation is to develop a new method, simple and cheaper, to quantify and monitor BTX in air using solid phase microextraction/ gas chromatography/mass spectrometry (SPME/CG/MS). The features of the calibration method proposed are presented in this dissertation. SPME sampling was carried out under non-equilibrium conditions using a Carboxen/PDMS fiber exposed for 10 min standard gas mixtures. It is observed that the main parameters that affect the extraction process are sampling time and concentration. The results of the BTX multicomponent system studied have shown a linear and a nonlinear range. In the non-linear range, it is remarkable the effect of competition by selective adsorption with the following affinity order p-xylene > toluene > benzene. This behavior represents a limitation of the method, however being in accordance with the literature. Furthermore, this behavior does not prevent the application of the technique out of the non-linear region to quantify the BTX contents in the atmosphere.

Extração de ferro da cera de carnaúba utilizando sistemas microemulsionados

The constant search for biodegradable materials for applications in several fields shows that carnauba wax can be a viable alternative in the manufacturing of biolubricants. Carnauba wax is the unique among the natural waxes to have a combination of properties of great importance. In previous studies it was verified the presence of metals in wax composition that can harm the oxidative stability of lubricants. Considering these factors, it was decided to develop a research to evaluate iron removal from carnauba wax, using microemulsion systems (Me) and perform the optimization of parameters, such as: extraction pH, temperature, extraction time, among others. Iron concentration was determined by atomic absorption and, to perform this analysis, sample digestion in microwave oven was used, showing that this process was very efficient. It was performed some analysis in order to characterize the wax sample, such as: attenuated total reflectance infrared spectroscopy (ATR-IR), thermogravimetry (TG), differential scanning calorimetry (DSC), energy dispersive X-ray fluorescence (EDXRF), scanning electron microscopy (SEM) and melting point (FP). The microemulsion systems were composed by: coconut oil as surfactant, n-butanol as cosurfactant, kerosene and/or heptanes as oil phase, distilled water as water phase. The pH chosen for this study was 4.5 and the metal extraction was performed in finite experiments. To evaluate Me extraction it was performed a factorial design for systems with heptane and kerosene as oil phase, also investigating the influence of temperature time and wax/Me ratio, that showed an statistically significant answer for iron extraction at 95% confidence level. The best result was obtained at 60°C, 10 hours contact time and 1: 10 wax/Me ratio, in both systems with kerosene and heptanes as oil phase. The best extraction occurred with kerosene as oil phase, with 54% iron removal