Análise exergética e ecológica de um sistema compacto de cogeração operando com gás de síntese

The aim of this work is to make a qualitatively and ecologically evaluation of a compact cogeneration system that operates with synthesis gas obtained from a gasifier. Using the Eucalyptus Biomass as fuel, that passes through a wood gasifier (Drowndraft type) and supply the internal combustion engine. The compact cogeneration system is composed of two heat exchangers, an energy generator connected to an internal combustion engine and an absorption refrigeration system. The complete system is installed in the laboratory from the Energy Department at the University of Guaratinguetá. By the analysis related to the First and Second Thermodynamic Laws applied in this system, was possible to identify the mass flows in each point, energetic efficiency, irreversibility and exergetic efficiency. The components that have the biggest irreversibilities are the gasifier, followed by the internal combustion engine, which should be focused in future improvements. The system efficiency in energetic basis is 51,84% and in exergetic basis is 22,78%. Using the ecologic efficiency methodology was possible to identify the emissions rates, the pollution indicator associated to the combustion of the synthesis gas in the internal combustion engine. The ecologic efficiency considering the energectic analysis is 91,73%, while considering the exergetic analysis, 83,65%. It is concluded that the use of the synthesis gas in a compact cogeneration system is viable from the technical and ecological point of view, making possible to generate energy for isolated communities and promoting the decentralized electricity generation

Obtenção de constantes elásticas da madeira de duas espécies de Pinus sp

There are many studies about longitudinal modulus of elasticity of wood, but you can´t say the same of transverse modulus, especially for conifers. The study aimed to characterize and compare the species Pinus elliottii var. elliottii and Pinus elliottii var. elliottii x Pinus cariabeae hondurensis (hybrid), and the longitudinal modulus of elasticity (E) and lateral (G) in bending, to analyze the modulus of elasticity in different spaces and to verify the species studied the ideal range is equal to 21 times the height of the specimen, as prescribed in the normative document NBR 7190/1997, as well as analyzing the relationship G = E/20 defined in the normative document NBR 7190/1997. The wood came from the farm located in Paranapanema, split at the mill São José and the rest of the work was conducted at the Experimental Itapeva Campus - UNESP. Were removed fourteen specimens of each species. The average values of the modulus of elasticity and cross were, respectively, 5828 MPa and 452 MPa for Pinus elliottii var. elliottii and 6407 MPa and 320 MPa for the species of Pinus elliottii var. elliottii x Pinus cariabeae hondurensis (hybrid). The trend lines for the plotted graphs showed an exponential behavior to near linear 21he will equal the constant after this value. We have found the relationship G = E/13, for Pinus elliottii var. elliottii and G = E/20 for hybrid. The results of the modulus and strength for Pinus elliottii var. elliottii and the hybrid were lower than those reported in the literature, showing that this batch inferior quality to apply to structures

Efeitos da variação do teor de umidade da madeira no processo de lixamento

The process of sanding wood is little known and industries use it in a practical way without having studied their best conditions before. There are few studies involving this type of machining. On this basis, this paper studied the effects of varying moisture content of the wood surface quality after the sanding process. It was used a sanding machine with flat horizontal cut parallel to the fibers, using: 02 different species (Pinus elliottii and Corymbia citriodora); 01 sanding abrasive (aluminum oxide) and 03 different particle size abrasives ( P80 , P100 and P120 ) . Initially, the pieces were acclimatized ( 2 ± 7% , 12% and 17% ± 2 ± 2 ) and subsequently passed by the sanding process, and therefore, the surface roughness was analyzed. For each condition, were performed 06 repetitions totaling 54 trials for each species. We analyzed the effects of wood moisture by capturing the power sanding, rougheness, acoustic emission and maximum temperature during the sanding process. The variation of moisture content produced changes in the surface quality of the finished parts, and these changes were more marked in Pinus than Corymbia. During the sanding process of the specimens with 7 % and 12 % humidity, there was a lower noise emission, power consumption and heating surface. When checking the roughness of these parts after this process, it was observed that the surface quality of them were superior in the parts sanded containing 17 % moisture

Ensaio de ligações de estruturas de madeira por chapas com dentes estampados em quatro espécies da família leguminosas

In the last years, the use of industrialized systems of lattice structures of wood as an alternative in the construction processes, is becoming more popular in Brazil, mainly for their commitment to the environment.The industrialized system of wooden lattice structures consists in a production of lattice structures, composed of pieces of wood where their mechanical connections are made with the sheet multi-toothed connectors (CDE).Among the many challenges to make this system competitive, the whole system of the connections between the pieces of wood not only must show functionality, but also speed, strength, versatility and economy. Referenced at Brazilian Standard for Wood Structures (NBR 7190/1997 - Project of timber structures) the sheet multi-toothed connectors, are analyzed using three test methods: tensile strength parallel to grain, tensile strength normal to the fibers and shear strength, all of them in two positions, αCH0=0o e αCH0=90o to four types of wood: Angelim (Vatairea heteroptera Ducke); Red-Angico (Parapiptadenia rigida (Benth) Brenae); Garapa (Apuleia leiocarpa (Vog.) Macbr) and Jatoba (Hymenaea stilbocarpa Hayne), belonging to the Leguminosae family and founded in several regions of Brazil.The purpose of this manuscript consists to analyze the mechanical connections with the sheet multi-toothed connectors through tests from NBR7190/1997

Iniciativa para integração da infraestrutura regional Sul-americana (IIRSA): a construção do complexo do Rio Madeira e seus impactos socioambientais

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Análise da troca de calor em sistemas de injeção de termoplásticos – um estudo de caso: polipropileno

The purpose of this work was to define the processes through which the cooling of thermoplastics parts occur inside the mold cavity in an injection process. The plastic materials have become more widespread in the automobile industry and, among its manufacturing processes, injection moulding develops quickly, allowing the manufacturing of quality parts in great volumes. Data was collected from the injection of Volkswagen Gol NF 23X (Gol Generation 5). Using approximated methods for calculation for the heat Exchange inside the mould, in the cooling system, the required water flow was determined to properly cool the parts. Comparing the obtained value with Project specifications, it was verified that the method, in spite of incurring in some mistakes, is efficient in determining the flow of cooling fluid and serves as a verification tool for the parameters defined on project, and can be applied to simple projects. The definition of the cooling system, in practice, is dependent on innumerable variables and each case must be approached in itself, since the parameters for one product may not be ideal for another

Estudo das propriedades mecânicas da madeira plástica

This work has in its outline the analysis of the mechanical properties of the composition of plastic residues, denominated “plastic wood”, aiming at establishing technical parameters for application of this material in substitution to the natural wood. Plastic-Wood is basically, a combination of several kind of plastic, previously selected, washed, dried and without metallic particles, which are agglomerated, extruded or introduced into a mold. The manufacturer can choose different formats and colors. During this monograph it can be observed the use of several kind of plastic, their mechanical properties and the plastic-wood production process. Also are presented features and applications of natural wood, in order to better compare their uses in several applications

Desempenho estrutural de vigas em madeira laminada colada armada

The objective of the present work was to evaluate Pinus’ glued laminated timber (glulam) beams and steel reinforced glulam beams, using PU mono-component adhesive in lamination step and epoxy adhesive to bond steel bars. The mechanical performance was verified through bending test, and the adopted method based on homogenized section, to considerate the differences between wood and steel mechanical properties. The homogenization section method proved itself effective in obtaining the stiffness of the parts in MLCA. The stiffness of reinforced beams increased 91% in comparison with glulam beams, differing only 5.5 % from value of stiffness calculated

Proposta de conector para ensaios de ligações CDE submetidas à tração perpendicular as fibras em madeira de pinus

The growth of urban population associated with the shortage of supply of public infrastructure such as hospitals, kindergartens, schools, among others, has reinforced the need to develop alternative methods that simplify the construction processes and allows for a reduction in these costs works. The conventional processes have increasingly been shown ineffective to solve the problem of demand for different types of urban and rural buildings. Given this fact, industrial construction processes can gain space and have proven to be highly interesting to solve the above problems, in particular, considering the cost-effective and time. Therefore, this study aimed to determine the influence of moisture on the strength of metal plate connections connectors (printed plate with teeth). For the sizing of the links between structural lumber using metal connectors with teeth prints; controlled process variables (drying of the wood and the different moisture contents), and finally found results and compare them with different literatures order to obtain a qualitative efficiency of the process. Some specimens had very low expectations, can be explained by the presence of bone marrow, and pre-existing cracks. Thus, the results were discarded for further analysis and more accurate results

Análise geoestatística da variabilidade espacial do acabamento com tingidor em painéis de madeira colada lateralmente

Classical statistical techniques which necessarily assume that all sampling units are random and independent were always used in the timber industry. Geostatistics considers that certain phenomena are characterized by spatial dependence: values of sampling units closer to each other tend to be more similar than values of sampling units farther away. This study aimed to characterize the spatial variability of the finishing (dyer) in the upper and lower surfaces of four edge glued panels by using geostatistical methods using geoR. Semivariograms were constructed for the analysis of spatial dependence. The spherical mathematical model was the best fit to the semivariograms generated, and was done the interpolation of the data (kriging) in samples where the distribution of dyer presents spatial dependence. In the bottom surfaces of two panels where the spatial dependence was detected geostatistical methods characterized a very large spatial variability due to the heterogeneous application of the finishing

Produção e caracterização físico-mecânica do compósito cimento-madeira com variação granulométrica dos resíduos lignocelulósicos

The need to reduce environmental damage and add value to waste causes more and more new alternatives appear to unite these two points. One of the main ways to achieve this in timber industries and the use of waste for making panels. This work was aimed at studying the influence of particle size and density in Eucalyptus mechanical compressive strength of cement composite wood. For this study was performed production and physico-mechanical characterization of specimens, using portland cement, water and waste eucalyptus. The methodology consists of a statistical study of the results obtained by calculating the density and axial compression tests and a subsequent comparison of these results with other studies. The results showed that there are significant differences in density and compressive strength when using different particle sizes the particles of eucalyptus. In general, the smaller the particle size, the lower the compression strength and the greater the density when the samples are produced with the same trait

Análise dos efeitos das deformações estruturais sobre a transferência transversal de carga em um veículo do tipo fórmula SAE submetido a uma aceleração lateral constante

This paper studies the frame deformations on a formula SAE vehicle in steady-state cornering and its influence on the lateral load transfers and, consequently, on the tires normal loads due to the applied lateral load. For a vehicle with a perfect rigid frame, the vehicle mass, the position of the center of gravity and the suspensions are the only factors responsible for the load distribution between the tires. When the frame deformations are no longer negligible, the frame deformations affect the loaddistribution between the tires. The frame flexibility turns it able to behave as an additional set of springs to the suspension system, thus changing the behavior of the set. This paper describes howit happens and suggests ways to minimize this phenomenon

Energia, suas formas e transformações: uma abordagem contextualizada por meio de material não-formal

Energy is a physical quantity very present in physics. Although extremely useful, its concept is very abstract for most students in high school and college. Identify the presence and form of energy in a given phenomenon is not simple, as there is immediate understanding on the transfer and transformation. This work emphasizes the study of mechanical energy in its different forms as well as the thermal energy, considering the possible transformations between them. To this end, use is mad of toys, exploring its potential as an alternative material to be use in supplement classroom teaching in primary and secondary levels. The proposed use of ludic pedagogy takes into account the author’s experience as an intern project Toy Scientific Department of Physics and its role as mediator in the workshops offered by the project to school at these levels

Viabilidade do aproveitamento de resíduos de madeira para produção de móveis

The need to use waste from wood processing industry grows due to environmental demands imposed by laws, so like the need to introduce more competitive products in the market (it means better quality and acceptable cost) who must submit by the rational use of raw material, usually turning waste to sub products, what adds higher value for that. To this research, specific case from Ribon Company, located on Camaçari, Bahia-Brazil, has been studied. It is a treated wood producer. Bulk of monthly wood logs there is 70 m3. Its yield is 71,43%, where bulk of generated waste is monthly 20m3. As an exploitation way from generated waste, it has been suggested some options like: erosion protection to specific areas, a wildlife shelter as an henhouse etc, recreational articles, coal, linings, treadmills. However this research will give focus to the furniture design made of waste. As a conclusion, there is very much need to assign new utilizations to that sub used materials, since there is significant amount to increase company’s productive yield

Produção de carvão vegetal a partir da madeira de Eucalyptus saligna clone SI70 com tres anos e meio de idade

Charcoal is obtained from carbonization, much used in the steel industry for ore reduction, using as raw material the Eucalyptus. The present study aims to verify whether the main Eucalyptus saligna genetically modified produce quality charcoal with only 3.5 years old. The study was done with material collected from three trees, divided into five discs removed at 0, 25 , 50 , 75 and 100 % of the commercial height of the tree. The procedures adopted were based on standards published by ABNT. The results were satisfactory for the parameters: basic wood density with an average of 0.39 ± 0.0082 g / cm ³; volatile materials from coal with an average of 19.35 ± 3.27 %, fixed carbon content of the coal with an average of 75.62 ± 3.40 % and gross calorific value of coal with an average of 4694.43 cal / g, and unsatisfactory results for ash content averaging 5.03 ± 0.23 when compared to the values found in the literature. It was concluded that the studied wood is able to produce charcoal, but the factors of production should be better observed, such as heating time which exerted direct influence on the determination of ash content