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

Produção de biodiesel a partir de óleo de coco (Cocos nucifera L

The production of biodiesel has become an important and attractive process for the production of alternative fuels. This work presents a study of the biodiesel production from coconut oil (Cocos nucifera L.), by two routes: direct transesterification using NaOH as catalyst and esterification (with H2SO4) followed by basic transesterification. The reactor was built in pirex with 1L of capacity and was equipped with a jacket coupled with a thermostatic bath to temperature control, a mecanical stirring is also present in the reactor. The analysis of oil composition was carried out by gas chromatography and esters compounds were identified. The parameters of molar ratio oil/alcohol, reaction time and temperature were studied and their influence on the conversion products was evaluated using experimental planning (23). The molar ratio was the most significant variable by the statistical planning analysis. Conversions up to 85.3% where achived in the esterification/transesterification, with molar ratio 1:6 at 60ºC and 90 minutes of reaction. For the direct transesterification, route conversions up 87.4% eas obtained using 1:6.5 molar ratio at 80ºC and 60 minutes of reaction. The Coconut oil was characterized by their physic chemical properties and key constituents of the oil. The lauric acid was the main constituint and the oil showed high acidity. The biodiesel produced was characterized by its main physicochemical properties, indicating satisfactory results when compared to standard values of National Petroleum Agency. The work was supplemented with a preliminary assessment of the reaction kinetic

Avaliação e modelagem reológica de fluido de perfuração base água

The determination of the rheology of drilling fluids is of fundamental importance to select the best composition and the best treatment to be applied in these fluids. This work presents a study of the rheological behavior of some addictives used as viscosifiers in water-based drilling fluids. The evaluated addictives were: Carboxymethylcellulose (CMC), Xanthan gum (GX), and Bentonite. The main objective was to rheologically characterize suspensions composed by these addictives, by applying mathematical models for fluid flow behavior, in order to determine the best flow equation to represent the system, as well as the model parameters. The mathematical models applied in this research were: the Bingham Model, the Ostwald de Wale Model, and the Herschel-Bulkley Model. A previous study of hydration time for each used addictive was accomplished seeking to evaluate the effect of polymer and clay hydration on rheological behavior of the fluid. The rheological characterization was made through typical rheology experiments, using a coaxial cylinder viscosimeter, where the flow curves and the thixotropic magnitude of each fluid was obtained. For each used addictive the rheological behavior as a function of temperature was also evaluated as well as fluid stability as a function of the concentration and kind of addictive used. After analyses of results, mixtures of polymer and clay were made seeking to evaluate the rheological modifications provided by the polymer incorporation in the water + bentonite system. The obtained results showed that the Ostwald de Waale model provided the best fit for fluids prepared using CMC and for fluids with Xanthan gum and Bentonite the best fit was given by the Herschel-Bulkley one

Reaproveitamento e caracterização dos resíduos orgânicos provenientes do Programa MESA DA SOLIDARIEDADE da CEASA/RN

As an auxiliary tool to combat hunger by decreasing the waste of food and contributing for improvement of life quality on the population, CEASA/RN has released from August/03 to August/05 the program MESA DA SOLIDARIEDADE. Despite of the positive results of this program, that has already distributed around 226 tons of food, there is still food being thrown in the trash as the deliver of the same food in its natural form would be a health risk to those who would consume it and only the correct processing of this food can make it edible. This work has as a goal the reuse of solid residues of vegetal origin generated by the CEASA/RN, through the Program MESA DA SOLIDARIEDADE and the characterization of the product obtained so it might be used as a mineral complement in the human diet. To the collecting of samples (from September until December /2004) it was developed a methodology having as a reference the daily needs of mineral salts for infants at the age of seven to ten. The sample was packed in plastic bags and transported in an ambient temperature to the laboratory where it was selected, weighted, disinfected, fractionated and dried to 70ºC in greenhouse. The dry sample was shredded and stored in bottles previously sterilized. The sample in nature was weighted in the same proportion of the dry sample and it was obtained a uniform mass in a domestic processor. The physical-chemical analyses were carried out in triplicate in the samples in nature and in the dry product, being analyzed: pH, humidity, acidity and soluble solids according to IAL (1985), mineral salts contents (Ca, K, Na, Mg, P and Fe) determined by spectrophotometry of Atomic Absorption, caloric power through a calorimetric bomb and presence of fecal traces and E. coli through the colilert method (APHA, 1995). During this period the dry food a base of vegetables presented on average 5,06% of humidity, 4,62 of pH, acidity of 2,73 mg of citric acid /100g of sample, 51,45ºBrix of soluble solids, 2.323,50mg of K/100g, 299,06mg of Ca/100g, 293mg of Na/100g, 154,66mg of Mg/100g, 269,62mg of P/100g, 6,38mg of Fe/100g, caloric power of 3,691Kcal/g (15,502KJ/g) and is free of contamination by fecal traces and E..coli. The dry food developed in this research presented satisfactory characteristics regarding to its conservation, possessing low calories, constituting itself a good source of potassium, magnesium, sodium and iron that can be utilized as a food complement of these minerals

Avaliação preliminar da viabilidade de produção in vitro de um isolado brasileiro de baculovírus Spodoptera frugiperda MNPV

In vivo production of viral biopesticides is the major source of viral insecticides currently in the marketplace. However, this system presents limitations during production scale-up. For the Spodoptera frugiperda nucleopolyhedrovirus (SfMNPV), the insect used for replication has cannibalistic characteristics, thus production is even more difficult. Insect cells are commonly used for in vitro baculovirus production. Most of these cell lines are derived from Lepidoptera species. The Sf21 cell line is derived from Spodoptera frugiperda caterpillar ovarian tissue, and its clonal isolate Sf9 has been used for biopesticide production due to its ease of growth in suspension cultures. In this work, the in vitro production capabilities of a Brazilian SfMNPV isolate obtained from cornfields was evaluated. Comparison of polyhedra production was carried out using both Sf21 and Sf9 cells, based on volumetric and specific yields. Both cell lines were cultivated in Hyclone medium supplemented with different fetal bovine serum concentrations (2,5 and 5%). The best results were obtained using Sf9 cells supplemented with 5% serum. These results were further confirmed quantitively through kinetic parameter estimation for both cells lines and different serum concentrations. After seven successive passages, this system still presented high specific polyhedra production

Desenvolvimento de um destilador solar para tratamento de águas de produção de petróleo com vistas a sua utilização na agricultura e geração de vapor

The production of petroleum is frequently accomplished with great volumes of water, that it is carried of the underground with the oil. It is a challenge of the present century the development of technologies that allow the use of waste water for purposes that consume great amounts of water and don't demand as rigid as the one of the drinking water requirements. The solar distillation has been configuring as an alternative of clean technology for desalination of brine and saline. Besides causing the minimum possible damage to the environment, it takes advantage of an abundant and free energy source: the solar energy. That study aims to develop a Solar Distillator for treatment of the produced water of the oil wells, to obtain an efluent to use in agriculture and vapor generation. The methodology for collection, conservation and analysis of the physical-chemical parameters obeyed the norms in APHA (1995). The sampling was of the composed type. Experiments were accomplished in the solar distillation pilot and simulation in thermostatic bathing. The operation was in batch system and for periods of 4, 6 and 12 h. The developed Distillator is of the type simple effect of two waters. It was still tested two inclination angles for covering; 20º and 45º. The Distillator presented minimum of 2,85 L/m2d revenues and maximum of 7,14 L/m2d. The removals of salts were great than 98%. The removal of TOC in the simulation was great than 90%. In agreement with the data of energy and mass balance, it was verified that the developed solar Distillator presented compatible revenues with those found in literature for similar types. It can be inferred that the obtained distilled water assists to the requirements CONAMA in almost all the points and could be used for irrigation of cultures such as cotton and mamona. As the distilled water has characteristics of fresh water it can be used in the generation of vapor

Desenvolvimento de um reator fotoquímico aplicável no tratamento de efluentes fenólicos presentes na indústria do petróleo

With water pollution increment at the last years, so many progresses in researches about treatment of contaminated waters have been developed. In wastewaters containing highly toxic organic compounds, which the biological treatment cannot be applied, the Advanced Oxidation Processes (AOP) is an alternative for degradation of nonbiodegradable and toxic organic substances, because theses processes are generation of hydroxyl radical based on, a highly reactivate substance, with ability to degradate practically all classes of organic compounds. In general, the AOP request use of special ultraviolet (UV) lamps into the reactors. These lamps present a high electric power demand, consisting one of the largest problems for the application of these processes in industrial scale. This work involves the development of a new photochemistry reactor composed of 12 low cost black light fluorescent lamps (SYLVANIA, black light, 40 W) as UV radiation source. The studied process was the photo-Fenton system, a combination of ferrous ions, hydrogen peroxide, and UV radiation, it has been employed for the degradation of a synthetic wastewater containing phenol as pollutant model, one of the main pollutants in the petroleum industry. Preliminary experiments were carrier on to estimate operational conditions of the reactor, besides the effects of the intensity of radiation source and lamp distribution into the reactor. Samples were collected during the experiments and analyzed for determining to dissolved organic carbon (DOC) content, using a TOC analyzer Shimadzu 5000A. The High Performance Liquid Chromatography (HPLC) was also used for identification of the cathecol and hydroquinone formed during the degradation process of the phenol. The actinometry indicated 9,06⋅1018 foton⋅s-1 of photons flow, for 12 actived lamps. A factorial experimental design was elaborated which it was possible to evaluate the influence of the reactants concentration (Fe2+ and H2O2) and to determine the most favorable experimental conditions ([Fe2+] = 1,6 mM and [H2O2] = 150,5 mM). It was verified the increase of ferrous ions concentration is favorable to process until reaching a limit when the increase of ferrous ions presents a negative effect. The H2O2 exhibited a positive effect, however, in high concentrations, reaching a maximum ratio degradation. The mathematical modeling of the process was accomplished using the artificial neural network technique

Degradação fotoquímica de hidrocarbonetos da gasolina em efluentes aquosos

Photo-oxidation processes of toxic organic compounds have been widely studied. This work seeks the application of the photo-Fenton process for the degradation of hydrocarbons in water. The gasoline found in the refinery, without additives and alcohol, was used as the model pollutant. The effects of the concentration of the following substances have been properly evaluated: hydrogen peroxide (100-200 mM), iron ions (0.5-1 mM) and sodium chloride (200 2000 ppm). The experiments were accomplished in reactor with UV lamp and in a falling film solar reactor. The photo-oxidation process was monitored by measurements of the absorption spectra, total organic carbon (TOC) and chemical oxygen demand (COD). Experimental results demonstrated that the photo-Fenton process is feasible for the treatment of wastewaters containing aliphatic hydrocarbons, inclusive in the presence of salts. These conditions are similar to the water produced by the petroleum fields, generated in the extraction and production of petroleum. A neural network model of process correlated well the observed data for the photooxidation process of hydrocarbons

Extração do óleo essencial de Cymbopogom winterianus J. com CO2 pressurizado

The extraction with pressurized fluids has become an attractive process for the extraction of essential oils, mainly due the specific characteristics of the fluids near the critical region. This work presents results of the extraction process of the essential oil of Cymbopogon winterianus J. with CO2 under high pressures. The effect of the following variables was evaluated: solvent flow rate (from 0.37 to 1.5 g CO2/min), pressure (66.7 and 75 bar) and temperature (8, 10, 15, 20 and 25 ºC) on the extraction kinetics and the total yield of the process, as well as in the solubility and composition of the C. winterianus essential oil. The experimental apparatus consisted of an extractor of fixed bed and the dynamic method was adopted for the calculation of the oil solubility. Extractions were also accomplished by conventional techniques (steam and organic solvent extraction). The determination and identification of extract composition were done by gas chromatography coupled with a mass spectrometer (GC-MS). The extract composition varied in function of the studied operational conditions and also related to the used extraction method. The main components obtained in the CO2 extraction were elemol, geraniol, citronellol and citronellal. For the steam extraction were the citronellal, citronellol and geraniol and for the organic solvent extraction were the azulene and the hexadecane. The most yield values (2.76%) and oil solubility (2.49x10-2 g oil/ g CO2) were obtained through the CO2 extraction in the operational conditions of T = 10°C, P = 66.7 bar and solvent flow rate 0.85 g CO2/min

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

Estudo da oxidação do metabissulfito de sódio contido no efluente da carcinicultura

The shrimp farming is a process of creation of shrimp that has been growing rapidly in the country, occupying a meaningful space in the Brazilian exporting. In 2003, this activity presented a volume of 60 millions of tons and 220 millions of dollars, being the main generator of employment and income of the primary sector of the northeast economy. However, it is a new activity with c.a. five years in the Rio Grande do Norte State and therefore needs investment in the technological area. Among the wastewaters of this activity, the sulphite solution is being usually applied in the process of fishing, i.e. retrieval of the shrimps from the farming. The aim of this work is to present the oxidation experimental results of the sulphite that may be and to determine what it s the most efficient method, trough laboratory experiments. The measurements were carried out in a mixing reactor inserting air and with hydrogen peroxide addition with and without UV light. The solutions were prepared synthetically with concentrations found in the wastewater of fishing and also collected in locu. The oxidation process using air was monitorated by iodometric analysis for the sulphite and the oxidation using hydrogen peroxide was evaluated with turbidimetric analysis for sulphate, by spectrophotometer. The sulphite was totally oxidized in both processes. The experimental results permit to conclude that the oxidation by hydrogen peroxide is more efficient and allowed to determine the optimum operational conditions in terms of concentration and time of treatment

Produção de quitosanase por aspergillus ochraceus em cultivo descontínuo submerso

In this work a 24 factorial design with triplicate at central point was used in order to investigate the influence of chitosan concentration (substrate) (Cs), culture media temperature (CMT), aeration ratio (AR) as well as agitation (A) on chitosanase production by Aspergillus ochraceus. Experiments were carried out using the following levels to the factors: (Cs) (-1) 0.1%; (0) 0.15%; (+1) 0.2%; (TMC) (-1) 25 minutes; (0) 30 minutes; (+1) 35 minutes; (RA) (-1) 0.4; (0) 0.6; (+1) 0.8; (A) (-1) 90 rpm, (0) 120 rpm, (+1) 150 rpm. One chitosanolytic activity (U.mL-1) was defined as the enzyme necessary to produce 1.0 mmol.min-1 of glicosamine by mL of extract. Chitosanolytic assays were carried out using two extract volumes, 0.05 and 0.1 mL, respectively. Results showed that was possible to produce chitosanase of order aproximatelly 5,9 U.mL-1 by Aspergillus ochraceus and chitosanolytic activity was increased by increment on substrate concentration, aeration ratio as well as agitation while media culture temperature increment decreased activity

Propriedades cerâmicas e imobilização do manganês em cerâmica estrutural

In this work is the addition of a metallic ion, of the metal Manganese, in a clay of Rio Grande do Norte state for structural ceramics use, the objective this study was to assess the evolution of ceramic properties. The clay was characterized by Chemical and Thermal analysis and Xray difraction. The metallic ion was added in the clay as aqueous solutions at concentrations of 100, 150 and 200 mg / L. The molded by extrusion and the burned were temperatures at 850, 950, 1050 and 1150 º C. Was made Chemical Analysis and investigated the following parameters environmental and ceramic: Solubility, Colour, Linear Retraction (%), Water Absorption (%), Gresification Curves, Apparent Porosity (%), Apparent Specific Mass (g/cm3) and Flexion Rupture Module (kgf/cm2). The results showed that increasing the concentration of metallic ion, properties such as Apparent Porosity (%), Water Absorption (%) decreases and the Flexion Rupture Module (kgf/cm2) increases with increasing temperature independent of the concentration of the ion. The gresification curves showed that the optimum firing temperatures were in the range between 950 and 1050 ° C. The evaluation of the properties showed that the ceramic material can be studied its use in solid brick and ceramic materials with structural function of filling. The results of solubility showed that the addition of ion offers no risk to the environment

Estudo das propriedades físico-químicas de biocombustíveis microemulsionados

The development of new fuels is an important field of scientific and technological activities, since much of the energy consumed in the world is obtained from oil, coal and natural gas, and these sources are limited and not renewable. Recently it has assessed the employment of microemulsions as an alternative for obtaining fuel isotropic between phases originally not miscible. Among many advantages, emphasizes the application of substances that provide the reduction of levels of emissions compared to fossil fuels. Thus, this work was a study of various microemulsified systems, aiming to check the performance of the winsor regions front of the use of surfactants: RENEX 18 → 150, UNITOL L-60 → L-100 and AMIDA 60, together with structure of esters from soybean and castor bean oils. From the results it were chosen four systems to physico-chemical analyzes: System I RENEX 60, Soil bean oil, methylic ester (EMOS) and water; System II RENEX 60/AMIDA 60, EMOS and water; System III RENEX 70, mamona oil methylic ester (EMOM) and water and System IV RENEX 95, EMOM and water. The tests of physico-chemical characterization and study of temperature increase were done with nine points with different compositions in a way to include the interest area (microemulsion W/O). After this study, was conducted a modeling to predict the viscosity, the property is more varied as function of compositions systems changes. The best results were the systems II and IV with a temperature stability above 60°C. The system I had its physico-chemical characterization very similar to a fossil fuel. The system II was the best one due to its corrosivity be stable. In the modeling the four systems had shown good, with an error that varied between 5 and 18%, showing to be possible the viscosity prediction from the composition of the system. The effects the microemulsion and the engine´s performance with the microemulsion were also avaliated. The tests were performed in a cycle-diesel engine. The potency and consumption were analysed. Results show a slight increase the rendiment fuel compared with the conventional as well as a decrease in specific consumption

Desenvolvimento de sistemas micro e nanoestruturados de quitosana/MDI para aplicações cosméticas

Currently, studies in the area of polymeric microcapsules and nanocapsules and controlled release are considerably advanced. This work aims the study and development of microcapsules and nanocapsules from Chitosan/MDI, using a new technique of interfacial polycondensation combined to spontaneous emulsification, for encapsulation of BZ-3. It was firstly elaborated an experimental design of 23 of the particle in white without the presence of BZ-3 and Miglyol, where the variables were the concentrations of MDI, chitosan and solvent. Starting from the data supplied by the experimental design was chosen the experiment with smaller particle diameter and only added like this BZ-3 and Miglyol. The suspension containing concentrations of 6.25 mg/mL, 12.5 mg/mL, 18.75 mg/mL, 25 mg/mL of BZ-3 were prepared, nevertheless, during the storage time, these formulations presented drug precipitates in the suspensions of 18.75 mg/mL and 25 mg/mL of BZ-3. This apparition of precipitate was attributed to the diffusion of BZ-3 for the aqueous phase without any encapsulation, suggesting so the use of the smaller concentrations of the BZ-3. The suspension containing 6.25mg/mL of BZ3 presented average size of 1.47μm, zeta potential of 61 mV, pH 5.64 and this sample showed an amount of BZ-3 and drug entrapment of 100 %. The suspension containing 12.5mg/mL of BZ-3 presented average size of 1.76μm, zeta potential of 47.4 mV, pH 5.71 and this sample showed an amount of BZ-3 and drug entrapment of 100 %. Then, showing such important characteristics, these two formulations were chosen for futher continuity to the study. These formulations were also characterized by the morphology, FTIR, stability for Turbiscan, DSC and a study of controlled release of the BZ-3 was elaborated in different receiving means