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Esse trabalho tem como objetivo explorar a relação entre o desenvolvimento dos intermediários financeiros e a volatilidade do crescimento econômico dos estados brasileiros, diante de choques reais e monetários. O trabalho realiza uma análise empírica com dados para os Estados brasileiros entre 2004 e 2015, estruturados em um painel dividido em três períodos, que visa calcular o impacto na volatilidade regional em diferentes instantes do tempo. Os resultados obtidos mostram que, diante de choques reais nos Estados, os intermediários financeiros locais atuam de forma a absorver a volatilidade do crescimento econômico. Por outro lado, os impactos estimados do sistema financeiro locais sobre os choques monetários estaduais foram não significativos.

The Development of new materials for building industry is a necessary issue to promote sustainability. Gypsum is an important low cost material very abundant in the northeast region of Brazil. Its physical properties make it an interesting material to form composite materials. This work presents a study of gypsum reinforced with Caroá (neoglasiovia variegate) natural fibers, where different amounts of fibers (1, 2, and 3%) were added into gypsum matrix. Three different fiber sizes (5, 10, and 20mm) were used to evaluate the effect of fiber size on the properties. PVAc was added in order to enhance the interactions between matrix and fibers. Mechanical strength was characterized by compression and bending tests. The addition of 1% mass Caroá fibers leads to a slightly increase on the mechanical strength independently of fiber size.

Calcium sulfate dehydrate β (CaSO4. 0,5H2O) is a material obtained from the calcination of gypsite (CaSO4.2H2O). This is a low cost ceramic material very used in building industry. The improvement of their applications is of fundamental technological interest. Polymers are an interesting alternative of reinforcement. Polyvinyl acetate (PVAc) is an addition polymer obtained by the polymerization of vinyl acetate. This polymer is well known to achieve good adhesion to cellulosic surfaces. The aim of this work was to evaluate the mechanical properties of porous plaster bodies reinforced with PVAc. Mechanical behavior was characterized by compression and bending strength. Three water / gypsum ratios: 0.5 0.6 and 0.7 were used on this work. An amount of 5% and 10% PVAc promoted increase on the mechanical properties of gypsum. Higher amounts polymer promoted further decrease of the mechanical properties.

Introdução: A dermatomiose juvenil (DMJ) é uma doença rara, embora seja a miopatia inflamatória mais comum da infância. O início precoce da terapia demonstrou diminuir consideravelmente a morbidade e a mortalidade da doença. Devido à raridade da DMJ, descrever novos casos se torna de grande valia para o processo de educação médica continuada em Pediatria. Objetivo: Relatar um caso único de DMJ atendido em nosso Serviço. Relato de Caso: Tratou-se de um paciente com histórico de atraso no desenvolvimento motor, que deu entrada em nosso Serviço com dois anos de idade devido a um quadro de fratura do fêmur esquerdo. Após primeira internação, prosseguiu com seguimento em ambulatórios de diversas especialidades, em uma tentativa de investigação multidisciplinar de seu quadro. Posteriormente, foi novamente admitido com quadro de febre e dor em membro superior direito. Durante seguimento com o reumatologista, observou-se que o paciente apresentava manifestações características da DMJ, como rash malar fotossensível, heliotropos e pápulas de Gottron. Posteriormente, iniciou tratamento com metilprednisolona em pulsoterapia por três dias, além de ciclos de ciclofosfamida, finalizando a terapia com prednisona 2mg/kg/dia. Desde então, o paciente mantém acompanhamento. Conclusão: A DMJ, apesar de sua habitual raridade, possui sinais característicos como rash malar fotossensível, miopatia proximal, heliotropos e pápulas de Gottron, que devem sempre ser considerados no diagnóstico e tratamento precoces. Além disso, a identificação de anticorpos específicos pode ser útil para o diagnóstico da maioria dos pacientes, e sinais não usuais como a coriorretinopatia podem indicar a presença da doença.

Studies to develop renewable fuels, such as biodiesel, as substitutes for petroleum diesel have a great environmental importance. However, in order to be effectively incorporated into the energy mix, a satisfactory performance of a diesel cycle engine under the effect of this biofuel must be ensured. The objective of this study was to evaluate the specifc fuel consumption, effective power and torque of a diesel engine related to resistive loads under varying volumetric proportions of soybean biodiesel in mineral diesel oil (5% (B5), 10% (B10), 25% (B25) and 50% (B50)) under varying applied loads (1.5, 3.0, 4.5, 6.0, 7.5 and 9.0 kW). For the test, a 7.36 kW engine coupled to a 28.8 kW three-phase electric generator was used. The loads were elevated up to 9.0 kW via a three-phase resistive bench. In terms of power and torque, the performances of the B5 and B10 mixtures were not signifcantly different, whereas the B25 and B50 mixtures displayed lower performances. The B10 mixture showed better performance in terms of consumption because the remaining mixtures had similar results to those B5 mixture. For this reason, it can be a basis for encouraging anticipation of this mixture in diesel cycle engines use. Additionally, the reduction in power and torque for mixtures with higher concentration of biodiesel should not be considered signifcant front the environmental gains from the use of renewable fuels and the analyzed technical aspects.

Porous bodies were produced using hydroxyapatite as a starting material, gypsum, high purity material, low cost and that can be molded into the desired shape. Also, beads of polystyrene polymer. The first step of this work was to produce porous gypsum blocks obtained by mixing gypsum, water and polystyrene. After drying, they were submerged in acetone solvent for solubilizing the polymer and pore formation. The porous hydroxyapatite was synthesized in a second stage, where the porous gypsum blocks were immersed in a solution of (NH4)2HPO4 0.5 mol L-1 to 100 ° C and pH 7.0-9.0 for 24 hours. From this method, it was possible to produce bodies single phase hydroxyapatite with a maximum porosity of 70 ± 3% and a compressive strength of 1.48 ± 0.17 MPa.

Brazil is one of the largest producers of mangoes, and the São Francisco Valley accounts for about 87 % of Brazilian exports of this product to the European market. This study aimed to characterize the mechanical behavior of the fruits according to the maturation stages, in order to prevent physical damage caused by improper handling of the fruit during harvest, storage, processing and transportation. The compression tests were performed on the mango cultivars (Mangifera indica L.) Keitt and Tommy Atkins at different maturation stages in order to characterize the internal elastic modulus and determine the maximum stress until rupture of the sleeve. The fruits showed a decrease in mechanical properties correlated with the increase of maturation stage, for both cutivars. The Tommy Atkins variety showed better mechanical properties probably related to a higher concentration of fibers in the pulp which yields better mechanical stabilization., Revista de Ciências Agrárias, vol. 40 n.º 2 (2017)

Hydroxyapatite (HA) is a bioceramic material with excellent biological properties. However, these properties are strongly dependent of its crystallinity degree, with high values of crystallinity associated to poor resorption rates and bioactivity. This work evaluates the properties of HA samples produced by two different free-forming conformation methods, CNC machining and 3D printing. In both cases, porous gypsum samples were produced and subsequently converted into HA in a reaction with di-ammonium hydrogen phosphate at 100°C and pH 8. A total conversion of the samples was achieved after 36h independently of the conformation method used. The microstructure, however, before and after the conversion is showed to be dependent on the method used. After conversion the machined samples achieved a maximum compressive strength of 3.5 MPaforporosities of circa 80%, while 3D printed samples achieved a tensile strength of 2.0MPa by porosities of 61%.

The gypsum is a versatile material that shows low thermal conductivity, which makes this material very suitable for application as thermal insulation. The increase of the porosity of gypsum bodies promotes a decrease on the thermal conductivity. This effect optimize the range of applications of gypsum on the thermal insulate field. The present study aimed the numerical modeling of two-dimensional heat conduction by finite differences in a steady state to evaluate the ortotrophy of the thermal conductivity of porous gypsum using the elements of the protected hot plate method. Computer simulations were performed using thermal conductivity of the gypsum equal to 0.35 W/m.K. This value was varied on the x and y directions by 5%, 10% and 15%. The heat flow applied to the numerical simulations were equal 75 W/m2, 100 W/m2 to 125 W/m2.It was possible to produce temperature profiles where is visible the displacement of isotherms as a function of the change in thermal conductivity in the x direction.

Hydroxyapatite (HA) is a ceramic material broadly studied due to its great similarity with the human bone. However, this material presents high stiffness and young modulus in comparison with the bone tissue. The polyhydroxybutyrate (PHB) is a themoplatic and biodegradable polymer that presents bone like young modulus and gradative degradation that results in a permanence of the mechanical properties after implantation. The aim of this study is to evaluate the effect of the infiltration of melted PHB on the mechanical properties of porose HA bodies. The composite samples were characterized by SEM, EDS and compressive strength. The samples produced with 10% paraffin and sintered at 1200 °C showed the best mechanical properties and reached an increase of the compressive strength from 29,00 ± 4,70 MPa before infiltration to 83,00 MPa ± 4,41 after infiltration with PHB for a final porosity of 5%.

O Brasil é um dos maiores produtores de manga e o Vale do São Francisco corresponde por cerca de 87% das exportações brasileiras deste produto para o mercado europeu. O objetivo deste estudo foi caracterizar o comportamento mecânico dos frutos de acordo com os estádios de maturação, a fim de evitar danos físicos causados pelo manejo inadequado do fruto durante a colheita, armazenamento, processamento e transporte. Os testes de compressão foram realizados nas cultivares de manga (Mangifera indicaL.) Keitt e Tommy Atkins em diferentes estádios de maturação para caracterizar o módulo elástico interno e determinar o estresse máximo até a ruptura da manga. Os frutos mostraram diminuição das propriedades mecânicas correlacionadas com o aumento do estádio de maturação, para ambos os cultivares. A variedade Tommy Atkins mostrou melhores propriedades mecânicas, provavelmente relacionadas a uma maior concentração de fibras na polpa, o que resulta em melhor estabilização mecânica., Brazil is one of the largest producers of mangoes, and the São Francisco Valley accounts for about 87 % of Brazilian exports of this product to the European market. This study aimed to characterize the mechanical behavior of the fruits according to the maturation stages, in order to prevent physical damage caused by improper handling of the fruit during harvest, storage, processing and transportation. The compression tests were performed on the mango cultivars (Mangifera indicaL.) Keitt and Tommy Atkins at different maturation stages in order to characterize the internal elastic modulus and determine the maximum stress until rupture of the sleeve. The fruits showed a decrease in mechanical properties correlated with the increase of maturation stage, for both cutivars. The Tommy Atkins variety showed better mechanical properties probably related to a higher concentration of fibers in the pulp which yields better mechanical stabilization.

Os materiais biologicos possuem propriedades elasticas e viscoelasticas, cujo conhecimento torna-se importante para o desenvolvimento de equipamentos e tecnicas adequadas de colheita, transporte e processamento de produtos horticolas. O presente trabalho apresenta os resultados das tensoes transversais maximas que causam a ruptura de abobora (Cucurbita moschata) das variedades leite e jacarezinho, atraves de ensaios mecânicos de compressao axial, evidenciando, dessa forma, quais as cargas maximas que sao capazes de provocar o rompimento das estruturas destes frutos. Foram analisadas as particularidades referentes a geometria das duas variedades de aboboras, realizando-se cortes em suas secoes transversais, para que fossem determinadas as tensoes de flexao e de compressao atuantes nas estruturas rigidas das hortalicas estudadas. Corpos de prova cilindricos, extraidos das polpas das aboboras, foram submetidos a ensaios de compressao axial, com o objetivo de se determinarem os coeficientes de Poisson distintos para ambas as variedades, cujos valores medidos sao 0,50 e 0,46, para as variedades leite e jacarezinho, respectivamente. O Modelo proposto para a analise da fratura nos frutos de abobora mostrou-se compativel com os dados experimentais resultando em um modo de falha por fratura longitudinal ao eixo de aplicacao das cargas. A carga transversal resultante e no minimo 4 vezes maior que a carga maxima de compressao aplicada para ambas as variedades.

β-Tricalcium phosphate (β-TCP) ceramics are of interest for bone requirements implants due to resoption behavior. The mechanical properties of β-TCP, however, are not yet sufficient to allow load bearing application of implants. The aim of this work was to investigate the effect of Mg2+substitution on the strength sintered TCP. Due to promotion of a liquid phase at 1200°C, Calcium pyrophosphate (CPP-C2P2O7) was used to improve the sintering of the samples. The introduction of CPP was promoted by use of a Ca/P molar ratio of 1.45. The powders were synthesized using a mixture of Ca (OH)2suspension and diluted H3PO4with addition of MgO and calcined at 750 °C, 900 °C and 1050 °C. The cold isostatic pressing compacts were sintered at 1200 °C and 1300 °C, respectively.It was shown that a small Mg content (1.5 mol%) increased both compressive strength and fractional density of the TCP material sintered at 1200 °C from 132 ± 39 MPa at 92.1 % of fractional density to 193 ± 29 MPa at 94.5 % of theoretical density. Higher amounts of Mg inhibited the grain growth provoking a increase of the boundary mobility activation energy. Abnormal grain growth (AGG) was observed after sintering at 1300°C, as result CPP - liquid phase formation. Increase of Mg content promoted AGG, due to inhibition of grain growth during normal grain growth resulting in a increase of the residual elastic energy of the system.

En este trabajo se caracteriza la respuesta mecánica del mango en función de los problemas encontrados durante las etapas de producción y comercialización. Problemas como daños físicos provocados por la manipulación inadecuada de la fruta, sea en el momento de la cosecha, almacenamiento, procesamiento o transporte. Los problemas señalados son característicos de la falta de información sobre el máximo esfuerzo que el fruto puede soportar sin que el mismo sufra daño interno o rotura externa que comprometa su comercialización. Fueron realizados ensayos de compresión en mangos (Mangifera Indica) de las variedades “Keitt” y “Tommy Atkins”, en la posición natural de reposo, lo que posibilitó la determinación del módulo de elasticidad y la fuerza máxima soportada en función de las fases 1, 2 y 3 de maduración. El módulo de elasticidad se reduce con el avance de la fase de maduración, obteniéndose valores para la variedad “Keitt” de 2,065 MPa, 1,734 MPa y 1,381 MPa para las fases de maduración 1, 2 y 3 respectivamente, y para la variedad “Tommy Atkins” de 1,698 MPa, 1, 657 MPa y 1,518 para las mismas fases de maduración. Las medidas de las fuerzas máximas, que antecede la rotura de la fruta, soportadas por la variedad “Tommy Atkins” fueron superiores a las soportadas por la “Keitt”. Este hecho está relacionado con la diferente organización estructural de estas dos variedades, en la que la variedad “Tommy Atkins” presenta un porciento de fibra superior a la variedad “Keitt”.

Calcium-deficient hydroxyapatite (CDHA) powders were synthesized by a wet chemical precipitation method using Ca(OH)2 and H3PO4 solutions. Single-phase β-tricalcium phosphate (β-TCP) powder with a molar (Ca+Mg)/P ratio of 1.5 was obtained after calcination of CDHA synthesized under vacuum. During synthesis in air, CO2 can be adsorbed and HBO42− is partly substituted by CO32−, resulting in a lower phosphorous content and consequently an increase of the molar (Ca+Mg)/P ratio to 1.53. A two-phase β-TCP powder containing 20 wt% hydroxyapatite (HA) was obtained after calcination. Samples prepared from β-TCP powders synthesized under vacuum achieved a compressive strength of 301±23 MPa at 99.6% fractional density, while TCP/HA samples prepared in air achieved a maximum compressive strength of 132±29 MPa at 91.7% fractional density. This decrease in strength can be correlated to the porosity retaining due to CO2 release during sintering and residual tensile stresses in the TCP matrix caused by the thermal expansion mismatch of β-TCP and HA.

Tricalcium phosphate based ceramics (TCP) are bioresorbable and thereby considered to be promising bone replacement materials. The differences in crystal structure between {alpha} and {beta}-TCP phases gives rise for different dissolution rates in vitro and in vivo, which may alter the bioresorbable behavior of TCP ceramics. It is suggested that the addition of magnesium ions, which are also present in biological tissues, stabilizes {beta}-phase to higher temperatures and thus enables the sintering of {beta}-TCP at elevated temperatures compared to Mg free TCP. In this paper, Mg-substituted TCP, with the general formula (Ca{sub 1-x}Mg {sub x}){sub 3}(PO{sub 4}){sub 2} and 0.01 {

This experiment was carried out to study the bioacaricidal activity of Neoglaziovia variegata against engorged females of Rhipicephalus (Boophilus) microplus. The mortality and fecundity of groups of engorged adult females exposed to different concentrations of ethanol, hexane, chloroform, and ethyl acetate extracts obtained from the leaves and aerial parts of N. variegata were evaluated, using three treatments with concentrations of 5, 10 e 25 mg/ml; two controls (distilled water and distilled water with drops of cremophor); with three replicates. The hexane extract of the leaves demonstrated significant results, presenting 94.1% inhibition of oviposition; 0.33% the average percentage of eclosion of eggs; and 99.8% of effectiveness. These results indicate N. variegata, particularly the hexane extract of leaves, as potential alternative control agents of R. (B.) microplus. Pharmacological and chemical studies are continuing in order to characterize the mechanism responsible for this effect.

Prototypes of porous hydroxyapatite (HAp) were produced from Gypsum/PVA composite, using a mass proportion of 15% polymer. The material was obtained by means of chemical conversion in (NH4)2HPO4 0.5 mol.L-1 solution and NH4OH 6.0 mol.L-1 alkaline medium for pH control, maintained between 6.0 and 9.0. The reaction occurred at a temperature of 100ºC at different test times. The obtained HAp was characterized by several techniques, such as FTIR, which identified the SO4(2-) groups characteristic for the Gypsum block, and the PO4(3-) groups that are attributed to the biomaterial HAp, besides XRD and SEM, which made it possible to confirm a successful conversion of the material. Tests for mechanical resistance to compression (σc) were carried out for both materials as well.

During handling operations, many problems that reduce the quality of vegetables may occur. Mechanical injuries are the leading cause of postharvest losses for the pumpkin, and can take place at any point of the production chain. This study aimed at evaluating the pumpkin fruits behavior, during their ripening stages, on the values of maximum compression force for fixed deformations, and determining the proportional deformability modulus of the fruits under compression at the repose position. Fruits were harvested at 15, 30, 40, 50 and 60 days after flowering and uniaxially compressed between two parallel plates. The results allowed to conclude that both the required compression force and the proportional deformability modulus increased during the maturation course, reaching a maximum force of 1,778 N and a maximum deformation modulus of 164 MPa, after 30 days. After this period, both the maximum force and the modulus values decreased, reaching 1,514.8 N of maximum force and a modulus of 132.09 MPa, after 60 days of ripening. Over the course of a longer maturation time, the fruit firmness increased, therefore requiring an increase in the maximum load to achieve greater deformation. The ideal period for harvest and transport of 'Jacarezinho' pumpkin fruits was set from 30 to 40 days after anthesis. Durante as operações de manuseio, podem ocorrer vários problemas que reduzem a qualidade das hortaliças. As injúrias mecânicas são a causa principal de perdas pós-colheita, para as abóboras, e podem ocorrer em qualquer ponto da cadeia de produção. Objetivou-se, com o presente trabalho, estudar o comportamento de frutos de abóbora, durante os estádios de maturação, nos valores da força máxima de compressão para deformações fixas, e determinar o módulo proporcional de deformidade desta hortaliça submetida a compressão, em posição de repouso. Os frutos foram colhidos aos 15, 30, 40, 50 e 60 dias após a fecundação e comprimidos uniaxicialmente, entre duas placas paralelas. A partir dos resultados obtidos, concluiu-se que tanto a força de compressão necessária, como o módulo proporcional de deformidade, aumentaram com a maturação, atingindo força máxima de 1.778 N e módulo de deformidade máxima de 164 MPa, após 30 dias. Após este período, tanto os valores da força máxima, quanto os valores do módulo, decresceram, chegando a 1.514,8 N de força máxima e módulo de 132,09 MPa, após 60 dias de maturação. Com o aumento do tempo de maturação, ocorreu aumento na rigidez dos frutos, com consequente aumento na carga máxima para atingir maiores deformações. O tempo ideal para colheita e transporte dos frutos da abóbora 'Jacarezinho' foi de 30 a 40 dias após a antese.

O ruído das máquinas agrícolas, com o passar do tempo, pode provocar problemas auditivos em seus operadores. O objetivo deste trabalho foi avaliar o nível de potência sonora emitido por trator agrícola, em condições estáticas e dinâmicas, comparando-o às normas IEC651 e IEC61672. O trabalho foi realizado na Universidade Federal do Vale do São Francisco, Petrolina (PE), em 2009, utilizando-se um trator Valtra, modelo 785 TDA sem cabine, e medidores do nível de potência sonora. As medições foram: estática (posições anterior, posterior, direita e esquerda do assento do operador a cada metro, até a distância máxima de 10 m, e diferentes rotações do motor, com dois equipamentos de medição) e dinâmica (cinco velocidades de deslocamento, em pista de concreto e terra batida, utilizando-se dois equipamentos de medição). Para os equipamentos que atendem às normas IEC651 e IEC61672, o segundo sempre apresentou maiores valores do nível de potência sonora, devido ao primeiro ser utilizado com protetor de vento. Em todas as condições, o nível de potência sonora foi maior do que o permitido pela legislação. À medida que se aumenta a rotação do motor, ocorre incremento no nível de potência sonora. Verificou-se que as pistas de terra batida e concreto podem ser utilizadas para análise do nível de potência sonora, devido aos resultados similares apresentados. A velocidade de deslocamento do trator influenciou no nível de potência sonora, sendo que as marchas mais longas apresentaram maiores valores.

O ruído das máquinas agrícolas, com o passar do tempo, pode provocar problemas auditivos em seus operadores. O objetivo deste trabalho foi avaliar o nível de potência sonora emitido por trator agrícola, em condições estáticas e dinâmicas, comparando-o às normas IEC651 e IEC61672. O trabalho foi realizado na Universidade Federal do Vale do São Francisco, Petrolina (PE), em 2009, utilizando-se um trator Valtra, modelo 785 TDA sem cabine, e medidores do nível de potência sonora. As medições foram: estática (posições anterior, posterior, direita e esquerda do assento do operador a cada metro, até a distância máxima de 10 m, e diferentes rotações do motor, com dois equipamentos de medição) e dinâmica (cinco velocidades de deslocamento, em pista de concreto e terra batida, utilizando-se dois equipamentos de medição). Para os equipamentos que atendem às normas IEC651 e IEC61672, o segundo sempre apresentou maiores valores do nível de potência sonora, devido ao primeiro ser utilizado com protetor de vento. Em todas as condições, o nível de potência sonora foi maior do que o permitido pela legislação. À medida que se aumenta a rotação do motor, ocorre incremento no nível de potência sonora. Verificou-se que as pistas de terra batida e concreto podem ser utilizadas para análise do nível de potência sonora, devido aos resultados similares apresentados. A velocidade de deslocamento do trator influenciou no nível de potência sonora, sendo que as marchas mais longas apresentaram maiores valores. The noise produced by farm machinery may cause hearing problems to its operators along the time. The objective of this study was to evaluate the sound power level emitted by agricultural tractor under static and dynamic conditions, in relation to the IEC651 and IEC61672 norms. It was conducted at the Universidade Federal do Vale do São Francisco, in Petrolina, Pernambuco State, Brazil, in 2009, by using a Valtra 785 TDA tractor without cabin and equipment to measure its sound power level. The measurements were: static (anterior, posterior, right, and left positions, in relation to the operator’s seat, for each meter along the maximum distance of 10 m, and different engine rotation speeds, with two measuring devices) and dynamic (five speeds on concrete and soil test tracks, with two devices). Two measurement devices were used to evaluate the sound power level. For the devices in accordance with the IEC651 and IEC62672 norms, the second one always presented higher sound power levels, due to the fact that the first one was equipped with a wind protector. In all positions, the sound power level was higher than allowed by law. As the engine rotation speed increases, the sound power level also increases. It was noticed that both test tracks can be used for sound power level analysis, due to their similar results. The tractor speed affected its sound power level, with higher values for longer gears.

The noise produced by farm machinery may cause hearing problems to its operators along the time. The objective of this study was to evaluate the sound power level emitted by agricultural tractor under static and dynamic conditions, in relation to the IEC651 and IEC61672 norms. It was conducted at the Universidade Federal do Vale do São Francisco, in Petrolina, Pernambuco State, Brazil, in 2009, by using a Valtra 785 TDA tractor without cabin and equipment to measure its sound power level. The measurements were: static (anterior, posterior, right, and left positions, in relation to the operator’s seat, for each meter along the maximum distance of 10 m, and different engine rotation speeds, with two measuring devices) and dynamic (five speeds on concrete and soil test tracks, with two devices). Two measurement devices were used to evaluate the sound power level. For the devices in accordance with the IEC651 and IEC62672 norms, the second one always presented higher sound power levels, due to the fact that the first one was equipped with a wind protector. In all positions, the sound power level was higher than allowed by law. As the engine rotation speed increases, the sound power level also increases. It was noticed that both test tracks can be used for sound power level analysis, due to their similar results. The tractor speed affected its sound power level, with higher values for longer gears.KEY-WORDS: Noise; ergonomics; agricultural mechanization.O ruído das máquinas agrícolas, com o passar do tempo, pode provocar problemas auditivos em seus operadores. O objetivo deste trabalho foi avaliar o nível de potência sonora emitido por trator agrícola, em condições estáticas e dinâmicas, comparando-o às normas IEC651 e IEC61672. O trabalho foi realizado na Universidade Federal do Vale do São Francisco, Petrolina (PE), em 2009, utilizando-se um trator Valtra, modelo 785 TDA sem cabine, e medidores do nível de potência sonora. As medições foram: estática (posições anterior, posterior, direita e esquerda do assento do operador a cada metro, até a distância máxima de 10 m, e diferentes rotações do motor, com dois equipamentos de medição) e dinâmica (cinco velocidades de deslocamento, em pista de concreto e terra batida, utilizando-se dois equipamentos de medição). Para os equipamentos que atendem às normas IEC651 e IEC61672, o segundo sempre apresentou maiores valores do nível de potência sonora, devido ao primeiro ser utilizado com protetor de vento. Em todas as condições, o nível de potência sonora foi maior do que o permitido pela legislação. À medida que se aumenta a rotação do motor, ocorre incremento no nível de potência sonora. Verificou-se que as pistas de terra batida e concreto podem ser utilizadas para análise do nível de potência sonora, devido aos resultados similares apresentados. A velocidade de deslocamento do trator influenciou no nível de potência sonora, sendo que as marchas mais longas apresentaram maiores valores. PALAVRAS-CHAVE: Ruído; ergonomia; mecanização agrícola.

ß-TCP und Mg-dotiertes ß-TCP wurden durch nasschemische Fällungsreaktion aus Calciumnitrat und Di-Ammoniumhydrogenphosphat hergestellt. Der Effekt von Reifungszeit, pH-Wert und Mg-Anteil auf das resultierende molare (Ca+Mg)/P Verhältnis und die Phasenzusammensetzung wurde analysiert. Mg-Dotierung führt zur Produktion von ß-TCP Mischkristall-Pulvern, aus denen vollständig verdichtete Keramikkörper mit verbesserten mechanischen Eigenschaften hergestellt werden können. Mit 1 Mol-% Mg dotiertem ß-TCP wird eine Sinterdichte von ca. 99% und Biegefestigkeiten von über 125 MPa erreicht. Die Erhöhung der Mg-Dotierung führt ebenfalls zu einer Steigerung der Bruchzähigkeit von 0.65  0.05 MPam-1/2 auf 1.14  0.04 MPam-1/2 für mit 1 Mol-% Mg dotiertem ß-TCP. Der Einbau von Mg2+ führt zu niedrigeren Löslichkeitsraten in wässriger Lösung im Vergleich zu b-TCP. Die mechanischen Eigenschaften nach Auslagerung in wässriger Lösung werden durch Bildung von Oberflächerissen reduziert, wobei b-TCP eine transkristalline Rissbildung und Mg-dotierte ß-TCP Mischkristall eine interkristalline Rissbildung zeigt. Die Synthese bei pH-Werten von unter 8.5 führt zur Bildung von ß-CPP als Sekundärphase, die einen negativen Einfluss auf die mechanischen Eigenschaften hat. Synthesen bei pH 8.5 und Reifungszeiten von länger als 24 h produzierten zweiphasige Pulver mit ca. 5 Masse-% HA als Sekundärphase. Die Anwesenheit von HA in einer ß-TCP Matrix begünstigt die Bildung von Zugspannungen in der Matrix und eine Abnahme der Bruchfestigkeit und Bruchzähigkeit. Für den umgekehrten Fall, bei dem die Matrix aus HA und die Partikel aus ß-TCP sind, ist eine Erhöhung der Bruchzähigkeit und der Bruchfestigkeit zu erwarten. ß-TCP and Mg substituted ß-TCP were synthesized by chemical reaction of Calcium nitrate and Di-ammoniumhydrogenphosphate. The effect of ripening time, pH and Mg amount on the phase composition of the powders was studied. Mg addition produces powders which can be used to manufacture dense ceramic bodies with increased mechanical properties. 1 mol-% Mg doted samples reaches a relative density of 99% and flexural strength of 126 MPa. Increase of the fracture toughness from 0.65  0.05 MPam-1/2 up to 1.14  0.04 MPam-1/2 is also caused by 1 Mol-% Mg substitution. The Mg substitution leads to lower solubility rates in aqueous solutions. The mechanical properties are reduced after soaking in water, due to formation of cracks at the surface. -TCP shows a transcrystalline crack formation and Mg-substituted TCP shows an intercrystalline crack formation. Single phase ß-TCP can only be synthesized by a controlled pH of 8.5 and after a ripening time of 5 h. Longer times and lower pH lead to formation of biphasic ceramics with reduced mechanical properties due to a negative effect of the second phase into the ß-TCP matrix. Residual stress is produced by the mismatch between the HA inclusions and the ß-TCP matrix. An increase of the mechanical strength and fracture toughness are expected for ß-TCP reinforced HA.