Desenvolvimento de compósito de pu de mamona com carga de resíduo de couro para isolação térmica

The standardization of the bovine skin thickness in the leather industry generates a residue known as wet-blue . At the end of twentieth century, the brazilian industry discarded about 131 thousand tons of this residue in nature, provoking a great environmental liability. In this paper is presented the analyses of the termophysical properties, thermal and volumetric expansion performance of a composite of vegetable resin of castor oil plant (Ricinus communis) with load of industrial residue of leather "wet-blue", for application as thermal isolation material of warm surfaces. There were considered four percentile levels of residue load in the proportions in mass of 0%, 5%, 10% and 15%, added to the expansible resin of castor oil plant in two configurations: sawed leather and crushed leather in a smaller particle (powder) by grinding in a mill of balls. Twenty-one proof bodies were produced for termophysical properties analysis (three for each configuration) and four proof bodies for rehearsals of thermal acting. Analyses of thermal acting were done in test cameras. The results of the rehearsals were compared to those obtained considering the castor oil plant foam without residue addition. A small reduction of the thermal conductivity of the composite was observed in the proportion of 10% of leather residue in both configurations. Regarding thermal conductivity, calorific capacity and diffusivity, it was verified that the proposed composite showed very close values to the commercial insulating materials (glass wool, rock wool, EPS). It was still demonstrated the technical viability of the use of composite as insulating thermal for systems of low potency. The composite presented larger volumetric expansion with 15% of sawed residue of leather.

Projeto, construção e análise de eficiência térmica de um sistema de aquecimento solar de água de baixo custo

We studied the feasibility of using a system of Solar Water Heating (SAS) with low cost, for three configurations. In configurations I and II have the collector grid absorber composed of six PVC tubes placed in parallel on the tile cement. In configuration II, the PVC tubes were transparent cover made of plastic bottles. Configuration III uses a collector composed of 12 black HDPE pipes, supported on four cement tiles 2.44 m x 0.50 m, two by two overlapping and interspersed with a filling of glass wool, comprising an area exposed to the global radiation incident of 2.44 m2, with the top two tiles painted matte black. In this configuration, the HDPE pipes replace conventional PVC pipes painted black. The total cost of SAS for configuration III, the most economical, was around $ 150.00. For the configurations tested the system of operation was thermosyphon collector. The study showed that the proposed systems have good thermal efficiency, are easy to install and handle and have low cost compared to conventional.

Mecanismos de desgaste, história térmica e ciclo de vida de componentes de um motor de combustão interna de aeromodelo

We developed an assay methodology that considered the temperature variation and the scanning electron microscopy as a method to quantify and characterize respectively the consumption evolution in three 46 LA machines, with internal combustion and two-stroke engines, 7.64 cm3 cylinder capacity, 23.0 millimeters diameter and 18.4 millimeters course, RPM service from 2.000 to 16.000 rpm, 1.2 HP power, and 272 grams weight. The investigated engines components were: (1) head of the engine (Al-Si alloy), (2) piston (Al-Si alloy) and (3) piston pin (AISI 52100 steel). The assays were carried out on a desktop; engines 1 and 2 were assayed with no load, whereas in two assays of engine 3 we added a fan with wind speed that varied from 8.10 m/s to 11.92 m/s, in order to identify and compare the engine dynamic behavior as related to the engines assayed with no load. The temperatures of the engine s surface and surroundings were measured by two type K thermopairs connected to the assay device and registered in a microcomputer with data recording and parameters control and monitoring software, throughout the assays. The consumed surface of the components was analyzed by scanning electron microscopy (SEM) and microanalysis-EDS. The study was complemented with shape deformation and mass measurement assays. The temperature variation was associated with the oxides morphology and the consumption mechanisms were discussed based on the relation between the thermal mechanical effects and the responses of the materials characterization

Desenvolvimento de um protótipo para alimentação de pós para aspersão térmica em tocha de plasma

The nanometric powders have special features that usually result in new properties, originating applications or expanding them in various fields of knowledge. Because having a high area/volume ratio, phenomena such as superficial strength of adsorption becomes greater than the weight of the powder which makes more difficult its handling. The high power of agglomeration of these powders requires study and development of equipments to enable its management into the plasma torch. The objective of this work is to develop a powder feeder which can solve the mainly problems about insertion of powder into the thermal spray developed in the laboratory of plasmas, which are carried out with plasma torch arc not transferred (plasma spray). Therefore, it was made a aluminum s powder feeder and tests were performed to verify their operation and determine its rate of deposition by spraying powders of niobium pentoxide (Nb2O5) and titanium dioxide (TiO2) with particle sizes less than 250 mesh (<0.063 mm). We used masses of 0.5 g - 1.0 g and 1.5 g of each powder in tests lasting 15 seconds - 20 to 25 seconds for each mass. The tests were performed in two ways: at atmospheric pressure using argon gas with a flow of 9 l / min as carrier gas and through a Venturi pipe also using argon gas with a flow of 9 l / min as carrier gas and with a flow of 20 l/min as the feed gas passing through the Venturi pipe. The powder feeder developed in this paper is very easy to be handling and building, resulting in feeding rate of 0.25 cm3/min - 1.37 cm3/min. The TiO2 showed higher feeding rates than the Nb2O5 in all tests, and the best rates were obtained with tests using mass 1.5 g and time of 15 seconds, reaching feeding rate of 1.37 cm3/min. The flow of feed had low interference in feeding rate during the tests

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

Resposta térmica de um compósito PEEK+PTFE+Fibra de carbono+grafite

Composites based on PEEK + PTFE + CARBON FIBER + Graphite (G_CFRP) has increased application in the top industries, as Aerospace, Aeronautical, Petroleum, Biomedical, Mechanical and Electronics Engineering challenges. A commercially available G_CFRP was warmed up to three different levels of thermal energy to identify the main damage mechanisms and some evidences for their intrinsic transitions. An experimental test rig for systematize a heat flux was developed in this dissertation, based on the Joule Effect. It was built using an isothermal container, an internal heat source and a real-time measurement system for test a sample by time. A standard conical-cylindrical tip was inserted into a soldering iron, commercially available and identified by three different levels of nominal electrical power, 40W (manufacturer A), 40W (manufacturer B), 100W and 150W, selected after screening tests: these power levels for the heat source, after one hour of heating and one hour of cooling in situ, carried out three different zones of degradation in the composite surface. The bench was instrumented with twelve thermocouples, a wattmeter and a video camera. The twelve specimens tested suffered different degradation mechanisms, analyzed by DSC (Differential Scanning Calorimetry) and TG (Thermogravimetry) techniques, Scanning Electron Microscopy (SEM) and Energy-Dispersive X-Rays (EDX) Analysis. Before and after each testing, it was measured the hardness of the sample by HRM (Hardness Rockwell M). Excellent correlations (R2=1) were obtained in the plots of the evaporated area after one hour of heating and one hour of cooling in situ versus (1) the respective power of heat source and (2) the central temperature of the sample. However, as resulting of the differential degradation of G_CFRP and their anisotropy, confirmed by their variable thermal properties, viscoelastic and plastic properties, there were both linear and non-linear behaviour between the temperature field and Rockwell M hardness measured in the radial and circumferential directions of the samples. Some morphological features of the damaged zones are presented and discussed, as, for example, the crazing and skeletonization mechanism of G_CFRP

Viabilidade térmica de um forno solar fabricado com sucatas de pneus

The proposed design provides a solar furnace alternative, box-like, low-cost operation to be used in cooking, comprising three scrap tires to make the recycling thereof. The tires were coupled to each other, forming an enclosure, which stood on its bottom covered by a parable multiple mirrors made from a urupema (sieve indigenous) and the inner sides of the oven aluminum sheet painted black, obtained from beer cans, thus being made to obtain the increase in the concentration of solar radiation incident on the inside of the prototype studied. Two tires were attached, leaving an air layer between them, with the function of thermal insulation. The third tire aimed to support the other two and thermally insulate the bottom of the oven. Externally was placed a metal frame with flat mirrors to reflect the incident rays into the oven, having a mobility to correct the apparent motion of the sun. Its primary feature is the viability of clean, renewable energy to society by tackling the ecological damage caused by the large-scale use of wood for cooking food. The tests show that the furnace reached the maximum temperature of 123.8 °C and baking various foods such as pizza, bun, and other lasagne in an average time 50 minutes. Proves the feasibility of using the oven. Presenting still able to improve their performance with the addition of new materials, equipment and techniques

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

Influência da intensidade de aeração na formação do floco de lodo ativado e na eficiência de remoção de matéria orgânica

In wastewater treatment, activated sludge systems have been a technology widely applied as secondary treatment. During this step, which has a strong biological aspect, it is necessary to introduce oxygen supply for the maintenance of metabolic activity of the bacteria through the aerators. Aeration devices are responsible for most of the energy consumption in this stage. In this background, the influence of three aeration intensities (atmospheric air flow 3.5, 7.0 and 10.5 L.min-1) and the concentration of dissolved oxygen (DO) on the dimension of activated sludge flocs as well as on the efficiency of organic matter removal were assessed using a traditional activated sludge system which was fed with synthetic domestic wastewater. Samples were taken weekly from the three units that make up the system feed, aeration and storage tank in order to verify the Chemical Oxygen Demand (COD). It was established the process efficiency through a comparison between the initial and final COD. Besides the parameters already mentioned, this monitoring work on activated sludge batch system was also observed by Mixed Liquor Suspend Solids (MLSS), Volatile Suspend Solids (VSS), pH and temperature measures. The results have showed a maximum removal efficiency around 75% in the first aeration sequence and approximately 85% for the second and third one. For the first aeration, the DO concentration remained higher than 3.0 mg.L-1 and a diameter range from 10 to 60 μm was observed. In the second e third sequence, the DO concentration remained higher than 4.0 mg.L-1 with a diameter range of 10 until 200 μm. Although the sequence 1 and 2 have presented similar performances for organic matter removal, the sequence 2 promoted a regular floc size distribution and with lower values of Sludge Volumetric Index (SVI) meaning a better flocculating ability. In addition, the results reaffirmed what the literature has reported: higher DO concentrations produce flocs with greater dimensions

Desenvolvimento de um programa de ensino de Física Térmica para o nível médio

Neste trabalho de mestrado, detemos nossa pesquisa na elaboração e implementação de planos de aula, que pudessem contribuir para estimular a participação e o interesse dos alunos nas aulas de física. Utilizamos como principal recurso didático, textos provenientes da Internet, que proporcionasse aos estudantes acesso a leitura envolvendo conteúdos científicos, tentando amenizar a falta de qualquer forma de material didático de ciências para os alunos. Pudemos constatar também, deficiências por parte dos educandos, em atividades que envolviam leitura e interpretação de textos, o que nos preocupou bastante enquanto educador e nos motivou a provocar mudanças neste quadro. As atividades aqui propostas foram elaboradas e aplicadas numa turma do segundo ano do nível médio, atendendo conteúdos de física térmica mas com um enfoque interdisciplinar. Cada plano de aula proporcionou participação ativa de cada estudante, seja na realização de tarefas solicitadas ou na participação de discussões em sala de aula. Os resultados mais expressivos desta pesquisa foram aumento na participação dos alunos nas atividades fora e dentro da classe e uma mudança na forma de pensar e elaborar soluções para determinados problemas

Exercício físico de baixa intensidade na dpoc: comparação dos programas solo e aquático

Physical Exercise (PE) is a necessary component in the management in COPD patients, where respiratory symptoms are associated with reduced functional capacity. Even with the increase in the number of studies that have been published and the therapeutics success using aquatic therapy approach, studies using PE in water in COPD patients are so few. Objective: the aim of this present study was to analyze the effects of low intensity water exercise in COPD patients, developed in two different places aquatic and ground. Methods: This is a randomized clinical trial study, 42 patients with moderate to very severe DPOC were recruited for the study, mean age of 63,2  10,9 years old. Randomized in 3 groups: Control Group (CG), Land Group (LG) and Water Group (WG). The PE protocol was performed in a period of 8 weeks, with frequency of 3 times per week. The CG participated in an educational program. All the patients were assessed twice through spirometry, respiratory muscular strength, the 6-min walk test, the quality of life (SF-36 and SGRQ), the LCADL, the MRC, the BODE index and the upper limbs (UP) incremental test. Results: There was a significant difference after the approaches in DP6 from the WG (p=0,02); in VEF1 in LG (p=0,00) and WG (p=0,01); in MIP in LG (p=0,01) and WG (p=0,02); in MEP in LG (p=0,02) and WG (p=0,01); the MRC decreases in WG (p=0,00). there was an increase of the weight supported by the UP in LG (p=0,00) and WG (p=0,01). The LG showed an increase of the quality of life represented by the SGRQ total score (p=0,00). The BODE index decreased in LG (p=0,00) and WG (p=0,01). In LCDAL, the LG showed a decrease. Conclusion: This data in this present study suggest that both approaches of low intensity exercise showed to be beneficial in moderate to very severe COPD patients. The WG showed additional benefits in physical function, pointing to a new therapeutic modality for COPD patients

Avaliação muscular respiratória: adaptação do mano vacuômetro nacional para a avaliação da pressão inspiratória nasal e nível de intensidade da ventilação voluntária máxima em sujeitos saudáveis

The clinical importance of evaluating the respiratory muscles with a variety of tests has been proposed by several studies, once that the combination of several tests would allow a better diagnosis and therefore, a better clinical follow of disorders of the respiratory muscles. This study aimed to evaluate the feasibility of adapting a national electronic manovacuometer to measure the nasal inspiratory pressure (study 1) and analyze the level of load intensity of maximum voluntary ventilation, as well as the variables that may influence this maneuver in healthy subjects (study 2). We studied 20 healthy subjects by a random evaluation of two measures of SNIP in different equipments: a national and an imported. In study 2 it was analyzed the intensity of the load of MVV test, change in pressure developed during the maneuver, the possible differences between genders, and the correlations between the flow developed in the test and the result of MVV. In study 1 it was found the average for both measures of nasal inspiratory pressures: 125 ± 42.4 cmH2O for the imported equipment and 131.7 ± 28.7 cmH2O for the national one. Pearson analysis showed a significant correlation between the average, with a coefficient r = 0.63. The average values showed no significant differences evaluated by paired t test (p> 0.05). In the Bland-Altman analysis it was found a BIAS = 7 cmH2O, SD 32.9 and a confidence interval of - 57.5 cmH2O up to 71.5 cmH2O. In the second study it was found significant differences between the genders in the air volume moved, being higher in males 150.9 ± 13.1 l / min vs 118.5 ± 15.7 L / min for (p = 0.0002, 95% CI 44.85 to 20:05). Regarding the inspiratory and expiratory loading, they were significantly higher in men than in women, peak inspiratory pressure (34.7 ± 5.3 cmH2O vs 19.5 ± 4.2 cmH2O, 95% CI - 18.0 to -12.3, p <0.0001), peak expiratory (33.8 vs. 23.1 ± 5.9 cmH2O ± 5.4 cmH2O, 95% CI -17.1 to - 4.6, p <0.0001), and the delta pressure (59.7 ± 10 cmH2O vs 36.8 ± 8.3 cmH2O, 95% CI 14.5 to 31.2, p <0.0002). The Pearson correlation showed that the flow generated by the maneuver is strongly correlated with the delta-expiratory pressure / inspiratory (r2= 0.83,R = 0.91, 95%IC 0.72 a 0.97 e p< 0.0001).Through these results we suggest that the national electronic manovacuometer is feasible and safe to perform the sniff test in healthy subjects. For the MVV, there are differences between the genders in the intensity of pressure developed during the maneuver. We found a load intensity considered low during the MVV, and found a strong correlation between the flow generated in the test and the delta pressure expiratory / inspiratory

Avaliação clínica do efeito da irradiação pós-opratória do laser de baixa intensidade na cicatrização de gengivoplastias em humanos

Many studies have been made to understand the process of tissular cicatrization, as well as the possible effects of laser therapy in the wound healing. However, the influence of low frequency laser irradiation in the repairing process is not completely understood. Our study has the purpose to assess clinically the effect of postoperative irradiation of the low frequency laser in humans, and the gingival repairing process postgingivoplasty performed with the extern bevel technique. Twenty-four patients with inflammatory gingival hyperplasia were enrolled in this study, which did not reduce with basic periodontal procedures, and patients with melanin pigmentation, with esthetic indications. After surgery the test group, randomly selected by a drawing, received laser application with energy density of 4 J/cm2, immediately after surgery and each 48 hours, during a week, with a total of 4 sections. The control group did not receive irradiation. The visual clinical analyses were performed by a single blind examiner, in the 2nd, 4th, 6th, 8th, 15th and 21st days post surgery. For statistic analyses of the data was used a Q-square test. Concerning the color, the results showed a better wound healing during days 6 to 8. when assessed the degree of progress of surgical wound, the results showed that the test group had a better cicatrization compared with the control group in the 2nd, 6th, 8th and 15th days post surgery, and at the 21st day both groups had the same results. Our results confirm that the laser had clinical influence in the repairing process after gingivoplasty surgery during days 2 to 15 post surgery

Ecologia comportamental de tropidurus Hispidus e Tropidurus Semitaeniatus (Squamata, Tropiduridae) em Simpatria, em área de caatinga do nordeste do Brasil.

This study evaluated the spatial, time and alimentary niches of Tropidurus hispidus and Tropidurus semitaeniatus in sympatry in a caatinga of Rio Grande do Norte, Brazil, as well as their foraging and termoregulatory behaviors, the activity body temperature and their reproductive and fat body cycles. Monthly excursions, from October 2006 to May 2008, were conducted at the Ecological Station of the Seridó (ESEC Seridó), Serra Negra do Norte municipality, using specific methodology for investigation of the aforementioned objectives. The two species presented similarities in space niche use, mainly in rocky habitat, however they differed in vertical microhabitat use with T. hispidus using a larger vertical microhabitat range. In the dry season the time of activity of both species was bimodal. In the wet season T. semitaeniatus showed a unimodal activity period, while T. hispidus maintained an bimodal activity period. In terms of importance in the diet, to both species, Hymenoptera/Formicidae and Isoptera predominated during the dry season. In the wet season, although Hymenoptera/Formicidae had larger importance among the prey items, lizards opportunistically predated on Lepidoptera larvae, Coleoptera larvae/adults and Orthoptera nymphs/adults. The foraging intensity revealed differences between the species, mainly in the wet season, when T. semitaeniatus was more active than T. hispidus. The mean activity body temperature of T. semitaeniatus was significantly higher than that of T. hispidus. The thermoregulatory behavior showed that during the dry season T. hispidus and T. semitaeniatus spent more time in shade or under filtered sun. In the wet season, T. hispidus did not show differences in the amount of time spent among the light exposure locations, however T. semitaeniatus spent most of their time exposed to direct sun or filtered sun. The reproductive cicle of T. hispidus and T. semitaeniatus occurred from the middle of the dry season to the beginning of the wet season. In both species, female reproductive activity was influenced by precipitation, whereas males exhibited spermatozoa in their testes throughout the year, and their reproductive activity was not related with any of the climatic variables analysed. In the two species, the fat storage varied inversely with reproductive activity, and there was no difference in fat body mass between females and males. We concluded that the segregation between T. hispidus and T. semitaeniatus in this caatinga area occurs in vertical space use, in the largest vagility of T. hispidus in microhabitat use and larger range size of their alimentary xviii items. Additionally, significant seasonal differences in relation to the activity period, body temperature, and foraging and termoregulatory behaviors between these two Tropidurus species facilitate their coexistence.

Investigação da estabilidade térmica e das propriedades elétricas do TiO2 em função da dopagem com Ce(SO4)2

The metalic oxides have been studies due to differents applications as materials semiconductor in solar cells, catalysts, full cells and, resistors. Titanium dioxide (TiO2) has a high electric conductivity due to oxygen vacancies. The Ce(SO4)2.2H2O doped samples TiO2 and TiO2 pure was obtained sol-gel process, and characterized by X-ray diffractometry,thermal analysis, and impedance spectroscopy. The X-ray diffraction patterns for TiO2 pure samples shows at 700°C anatase phase is absent, and only the diffraction peaks of rutile phase are observed. However, the cerium doped samples only at 900°C rutile in the phase present with peaks of cerium dioxide (CeO2). The thermal analysis of the TiO2 pure and small concentration cerium doped samples show two steps weight loss corresponding to water of hydration and chemisorbed. To larger concentration cerium doped samples were observed two steps weight loss in the transformation of the doped cerium possible intermediate species and SO3. Finally, two steps weight loss the end products CeO2 and SO3 are formed. Analyse electric properties at different temperatures and concentration cerium doped samples have been investigated by impedance spectroscopy. It was observed that titanium, can be substituted by cerium, changing its electric properties, and increased thermal stability of TiO2 anatase structure