Estudo de massa cer��mica triaxial visando �� otimiza����o do ciclo de queima da ind��stria de cer��mica estrutural

Over recent years the structural ceramics industry in Brazil has found a very favorable market for growth. However, difficulties related to productivity and product quality are partially inhibiting this possible growth. An alternative for trying to solve these problems and, thus, provide the pottery industry the feasibility of full development, is the substitution of firewood used in the burning process by natural gas. In order to contribute to this process of technological innovation, this paper studies the effect of co-use of ceramic phyllite and kaolin waste on the properties of a clay matrix, verifying the possible benefits that these raw materials can give to the final product, as well as the possibility of such materials to reduce the heat load necessary to obtain products with equal or superior quality. The study was divided into two steps: characterization of materials and study of formulations. Two clays, a phyllite and a residue of kaolin were characterized by the following techniques: laser granulometry, plasticity index by Atterberg limits, X-ray fluorescence, X-ray diffraction, mineralogical composition by Rietveld, thermogravimetric and differential thermal analysis. To study the formulations, specifically for evaluation of technological properties of the parts, was performed an experimental model that combined planning involving a mixture of three components (standard mass x phyllite x kaolin waste) and a 23 factorial design with central point associated with thermal processing parameters. The experiment was performed with restricted strip-plot randomization. In total, 13 compositional points were investigated within the following constraints: phyllite ≤ 20% by weight, kaolin waste ≤ 40% by weight, and standard mass ≥ 60% by weight. The thermal parameters were used at the following levels: 750 and 950 ��C to the firing temperature, 5 and 15 ��C/min at the heating rate, 15 and 45min to the baseline. The results showed that the introduction of phyllite and/or kaolin waste in ceramic body produced a number of benefits in properties of the final product, such as: decreased absorption of water, apparent porosity and linear retraction at burn; besides the increase in apparent specific mass and mechanical properties of parts. The best results were obtained in the compositional points where the sum of the levels of kaolin waste and phyllite was maximal (40% by weight), as well as conditions which were used in firing temperatures of 950 ��C. Regarding the prospect of savings in heat energy required to form the desired microstructure, the phyllite and the residue of kaolin, for having small particle sizes and constitutions mineralogical phases with the presence of fluxes, contributed to the optimization of the firing cycle.

Avalia����o de perdas invis��veis na colheita mecanizada em dois fluxos de massa de cana-de-a����car

In this work the performance of a sugar cane chopped harvester was analysed when fed with two sugar cane mass flows, measuring the invisible losses, which are impossible to measure in the field, harvester sugar cane cleaning efficiency and air velocity on extractors exit. The trial was done under controlled conditions at Copersucar Technology Center in January 2000. The results showed that the flow of sugar cane through the harvester doesn't influence the magnitudes of total invisible losses and raw material cleaning efficiency. The mean air velocity on the primary extractors exit was 12.0 m s-1, and 9.2 m s-1 on the secondary extractor, with a coefficient of variation of 21%, indicating that the poor cleaning performance of the harvester could be related to air velocity difference inside the extractor. Analyzing the data collected in the trials, it was possible to conclude that invisible losses in sugar cane harvester were 10% and the cleaning efficiency was 87%.

Transfer��ncia de massa e secagem em leitos vibrofluidizados: uma revis��o

Development of processing technology and equipments requires new methods and better quality of the processed product. In the continuous drying process, utilization of equipments that promotes an increment in the transfer coefficients becomes of the major interest. The use of vibrational energy has been recommended to the dispersed materials. Such method is based on the use of vibrational energy applied to disperse media. Thus, a literature review on the mass transfer and drying in vibro-fluidized beds was carried out, showing experimental results and mathematical modeling.

COMPARA����O DAS PROPRIEDADES REOL��GICAS DA MASSA DE CACAU TORRADA CONVENCIONALMENTE E POR MICROONDAS

Two kinds of roasting cocoa system: conventional batch method in electrical oven, and by microwaves, in a continuous microwave rotary applicator (2450MHz), were compared with respect to viscosity. Cocoa was roasted in whole beans and in nibs. The variable used in the microwave treatment was the power density applied to the whole beans (254,45 to 290,80 Wh/kg) and to the nibs (227,27 to 262,23 Wh/kg), with a constant holding time of 10 minutes. The variable used in the conventional roasting process was the roasting time of the beans (40 to 44 min) and the nibs (34 to 38 min), with constant temperature in the jacket of electric oven (150��C). Viscosity was measured in a Brookfield rheometer (mod RV-DVIII) at 40��C. In general, the plastic viscosity of the microwaved samples was lower than that of the conventional roasted samples. Also the nibs showed lower viscosities than the whole beans when roasted in the electric oven. The viscosity of the samples roasted in the microwave oven was lower in the whole beans than in the nibs. The product was sensorially evaluated by three experts in cocoa flavour, and it was shown that the flavour of the microwave roasted products was similar to that of the conventionally roasted products, with the advantage of a reduction in process time.

Compara����o preliminar entre ultrassonografia quantitativa de falanges e densitometria ��ssea na avalia����o da massa ��ssea em adolescentes

OBJECTIVE: To evaluate the association between quantitative ultrasonography at hand phalanges (QUS) and dual energy X-ray absorptiometry (DXA), and between these methods with food intake and history of bone fractures. SUBJECTS AND METHODS:After two years of follow up of 270 schoolchildren, 10 of them, who showed bone mass below - 2 SD in QUS, were included in the present study. Laboratory results and DXA data were analyzed. RESULTS: Bone mass evaluated by DXA at L1-L4 ranged from -2.8 to -1.1 SDS, and whole body bone mass, from -2.9 to -1.2 SDS. Three children had history of non-pathological bone fractures. Dietary assessment showed low intake of calcium in 10 cases, of phosphorus in 6, and of vitamin D in 8 cases. There were no differences among the cases of bone mass below-2 SD in any of the three used methods. There was no association between history of bone fractures and food intake, and between these evaluations and bone mass. CONCLUSION: In this small group of schoolchildren there was an association between the methods QUS and DXA. However, there was no association between bone mass and the history of bone fractures, or calcium, phosphorus and vitamin D intake.

Produ����o de massa seca, rela����o folha/colmo e alguns ��ndices de crescimento do Brachiaria brizantha cv. Xara��s cultivado com a combina����o de doses de nitrog��nio e pot��ssio

Objetivou-se avaliar a produ����o de massa seca das folhas, a rela����o folha/colmo e alguns ��ndices de crescimento do capim-xara��s submetido a doses de nitrog��nio (N) e pot��ssio (K). O experimento foi conduzido em casa-de-vegeta����o no per��odo de novembro/2004 a fevereiro/2005. Adotou-se esquema fatorial 4 <FONT FACE=Symbol>&acute;</FONT> 3, perfazendo 12 combina����es, as quais foram distribu��das em delineamento experimental inteiramente casualizado, com quatro repeti����es, perfazendo um total 48 unidades experimentais. Foram utilizadas quatro doses de N (0, 75, 150 e 225 mg dm-3) e tr��s doses de K (0, 50 e 100 mg dm-3). Verificou-se efeito das doses de N na produ����o de massa seca das folhas e na produ����o de massa seca total, em todos os cortes, com maior produ����o nas doses mais elevadas de N, ao passo que o K influenciou essas vari��veis apenas no segundo corte. A rela����o folha/colmo, a RAF, a AFE e a RPF somente foram significativas no terceiro corte da planta. Os efeitos das doses de foram decrescentes sobre essas vari��veis, enquanto as doses de K agiram de modo antag��nico ��s doses de N sobre a RAF e AFE.

Determina����o de minoxidil em formulações farmac��uticas usando permanganometria

Um m��todo cl��ssico para a determina����o de minoxidil em formulações farmac��uticas �� proposto baseado na rea����o redox entre KMnO4 e o minoxidil. Os melhores resultados na permanganometria foram obtidos usando concentra����es de 1,00 x 10-2 mol L-1 para o permanganato. O minoxidil foi usado como titulante na concentra����o de 2,00 x 10-2 mol L-1 dilu��do em solu����o de H2SO4 2,00 mol L-1. As recupera����es para m��todo proposto foram da ordem de 94,5 a 95,2 % dependendo da amostra comercial. O m��todo proposto foi aplicado �� amostras comerciais contendo minoxidil e comparado com resultados obtidos a partir de procedimentos cromatogr��ficos com erros relativos da ordem de -1 a -5,26%. O procedimento se mostrou simples, r��pido e pode ser uma alternativa para a determina����o de minoxidil em amostras farmac��uticas, nas quais a concentra����o do f��rmaco �� relativamente elevada.

Massa das sementes de Tecoma stans L. Juss. ex Kunth (Bignoniaceae): efeitos na emerg��ncia e desenvolvimento de suas pl��ntulas no sol e na sombra

The aim of this study was to evaluate the effect of Tecoma stans L. Juss. ex Kunth seeds mass on initial emergence, growth and, seedling development under different light conditions. The seeds were separated in four mass classes and sowed in four replicates of 24 seeds for each class, under full sun and canopy shade. Under sun environment was observed a greater percentage of emergence. Heavy seeds presented the greater percentage of emergence under both environments, but a greater rate was observed under canopy shade. One month after the start of experiments, the seedlings at the shade environment presented 100% of mortality. The growth and development seedlings under full sun were noticed for five months. In this period, only in the first three months was possible to observe the effects of Tecoma stans seeds mass on capacity of seedlings to acquire dry mass. The seedlings biomass partitions were similar among the tested mass class. The seedlings of smaller mass tended to a high specific leaf area in relation to the seedlings from large seeds, mainly in the first three months, resulting in a great acquisition of dry mass by these seedlings. In the fourth month, the specific leaf area did not present any tendency. Because the biggest seeds to give rise seedlings with best initial development than smallest seeds can be considered as species reproductive strategy. To produce seeds of different sizes also can be considered as way of species to spread in many microhabitats.

Aumento do ��ndice de massa corporal ap��s os 20 anos de idade e associa����o com indicadores de risco ou de prote����o para doen��as cr��nicas n��o transmiss��veis

OBJETIVO: Investigar fatores sociodemogr��ficos, de risco ou de prote����o para doen��as cr��nicas n��o transmiss��veis (DCNT) que se associem ao aumento do ��ndice de massa corporal (IMC) ap��s os 20 anos de idade. M��TODOS: Estudo transversal com 769 mulheres e 572 homens do Sistema Municipal de Monitoramento de Fatores de Risco para DCNT, 2005, Florian��polis, SC. O aumento do IMC foi definido em percentagem, pela diferen��a entre o IMC em 2005 e aos 20 anos. RESULTADOS: Desde os 20 anos, o aumento do IMC foi superior a 10% para a maioria dos indiv��duos. Nas an��lises m��ltiplas, o aumento do IMC foi associado a aumento da idade, baixo n��vel educacional (mulheres), ser casado (homens), n��o trabalhar, baixo n��vel de percep����o de sa��de, press��o alta, colesterol/triglicer��deos elevados (homens), realiza����o de dieta, sedentarismo e ex-tabagismo (mulheres). CONCLUS��ES: Estrat��gias de sa��de para prevenir o ganho de peso em n��vel populacional devem considerar principalmente os fatores sociodemogr��ficos.

Associa����o entre a perda de peso, a massa ��ssea, a composi����o corporal e o consumo alimentar de adolescentes obesos p��s-p��beres

OBJETIVO: Verificar os efeitos da perda de peso na densidade mineral ��ssea (DMO) de adolescentes obesos submetidos a interven����o com base em dieta hipocal��rica e orienta����es durante nove meses. M��TODOS: Realizaram-se avalia����es da antropometria, da composi����o corporal, da DMO e do consumo alimentar. RESULTADOS: Participaram do estudo 55 adolescentes, 78,2% meninas, com m��dia de 16,6 (1,4) anos. Destes, 44,4% n��o apresentaram redu����o do peso. O grupo que respondeu �� interven����o apresentou m��dia de perda de peso de 6,2% (4,6) do peso inicial. Houve aumento significativo da DMO e conte��do mineral ��sseo (CMO) entre os adolescentes n��o-respondedores e aumento do CMO e ��rea ��ssea entre os respondedores, associados, principalmente, com as altera����es da composi����o corporal com o ganho ou a perda de peso. CONCLUS��O: O aumento da massa ��ssea mesmo com a perda de peso demonstrou que o emagrecimento n��o ter efeito negativo do emagrecimento e denota prov��vel contribui����o da melhora dos h��bitos alimentares na aquisi����o ��ssea de adolescentes.

Determinantes do ��ndice de massa corporal em adolescentes de escolas p��blicas de Piracicaba, S��o Paulo

O objetivo do presente estudo foi verificar os fatores determinantes do ��ndice de massa corporal (IMC) de adolescentes matriculados nas escolas p��blicas de Piracicaba, S��o Paulo. A amostra foi constitu��da por 328 adolescentes de ambos os sexos, com idade m��nima de dez anos. Verificou-se peso, estatura, matura����o sexual, atividade f��sica e consumo alimentar. Foi usado um modelo de regress��o linear m��ltipla para verificar a associa����o entre as vari��veis independentes e o IMC. Enquanto as meninas consideradas fisicamente ativas apresentaram maior m��dia de IMC do que as insuficientemente ativas, a m��dia do IMC dos meninos n��o apresentou diferen��a estat��stica quando comparada entre meninos ativos e insuficientemente ativos. A matura����o sexual foi determinante do IMC, para ambos os sexos, refor��ando a ideia de que �� fundamental levar em considera����o essa vari��vel em estudos que avaliam o estado nutricional em adolescentes. Acredita-se que os m��todos utilizados no presente estudo, os quais s��o normalmente utilizados em pesquisas semelhantes, apresentaram importantes limita����es para avaliar a influ��ncia do n��vel de atividade f��sica e do consumo alimentar sobre o IMC dos adolescentes. Dessa forma, ressalta-se a necessidade de aprimoramento desses m��todos para ado����o em futuros estudos.

Associa����o entre o ��ndice de massa corporal de pais e de escolares de 7 a 14 anos de Florian��polis, SC, Brasil

OBJETIVOS: verificar a associa����o entre o ��ndice de Massa Corporal (IMC) de escolares de 7 a 14 anos e dos respectivos pais. M��TODOS: estudo transversal com 886 escolares de quatro escolas de Florian��polis, SC. Diagn��stico antropom��trico dos escolares e dos pais definido, respectivamente, a partir do IMC para idade de acordo com Centers for Disease Control and Prevention e dos pontos de corte da Organiza����o Mundial da Sa��de. A associa����o entre o IMC dos pais e dos escolares foi estimada por meio da raz��o de preval��ncia (RP) com intervalo de confian��a (IC) de 95% e teste qui-quadrado com valor de signific��ncia de p< 0,05. RESULTADOS: identificou-se preval��ncia de sobrepeso/obesidade mais elevada em meninos (29,9%) quando comparada a de meninas (17,7%) (p<0,001). Observou-se rela����o estatisticamente significante entre o IMC de escolares do sexo feminino com o IMC das m��es (RP=1,63; IC95%=1,1-3,0; p=0,02) e dos pais (RP=1,78; IC95%= 1,1-3,5; p=0,01). Nos escolares do sexo masculino a associa����o observada n��o foi estatisticamente significante. CONCLUS��ES: identificou-se que a preval��ncia do sobrepeso ou obesidade �� 1,63 vezes maior, entre as meninas, quando a m��e tamb��m apresenta esse dist��rbio e 1,78 vezes maior quando o pai o apresenta, em compara����o a m��es e pais eutr��ficos ou de baixo peso.

Estudo descritivo da massa ��ssea e fatores de risco cardiovasculares em mulheres com s��ndrome de Turner

A s��ndrome de Turner �� uma das doen��as gen��ticas mais comuns, ocorrendo em cerca de 1:2.500 rec��m-nascidas. Representa a forma mais freq��ente de hipogonadismo hipergonadotr��fico. O hipoestrogenismo �� a principal causa atribu��da ao aumento do risco de doen��as cardiovasculares, osteopenia e osteoporose. Diante da elevada incid��ncia dessas doen��as, o objetivo deste trabalho foi analisar a densidade mineral ��ssea das mulheres portadoras da s��ndrome de Turner e verificar a presen��a de fatores de risco de doen��a cardiovascular (DCV). Foram encontrados, pelo m��todo Dexa, 14,28 por cento das mulheres com densidade mineral ��ssea normal, 28,5por cento com osteopenia e 57,1por cento com osteoporose. Foi observada hipertens��o em uma mulher, obesidade em outra, diabetes em duas e todas referiram ser sedent��rias (sete). Ressalta-se, portanto a import��ncia da avalia����o precoce do tecido ��sseo e do rastreamento dos fatores de risco de DCV, assim como o controle dos fatores modific��veis e orienta����es de mudan��a do estilo de vida com finalidade preventiva

Estudo da massa espec��fica b��sica e da varia����o dimensional da madeira de tr��s esp��cies de eucalipto para a ind��stria moveleira

The utilization of wood from reforested species by the furniture industry is a recent trend. Thus, the present study determined the specific gravity and shrinkage of wood of 18-year-old Eucalyptus grandis, Eucalyptus dunnii and Eucalyptus urophylla, for use as components in solid wood furniture making. The tests to evaluate the specific gravity and shrinkage of wood in the radial and axial variation of the eucalyptus trees were performed according to NBR 7190/96. The results of the analysis of wood from eucalypt species were subjected to the Homogeneity Test, ANOVA, Tukey and Pearson correlation and compared to the performance of sucupira wood (Bowdichia nitida) and cumaru wood (Dipteryx odorata), often used in the furniture industry. The following results were found: Eucalyptus grandis had a lower value of shrinkage, being more suitable for furniture components that require high dimensional stability, as well as parts of larger surface. The wood of this species showed a rate of dimensional variation compatible with the native species used in the furniture industry. The radial variation of the wood was also verified, and a high correlation between specific gravity and shrinkage was found. Longitudinally, the base of the trunk of the eucalyptus trees was shown to be the region of greatest dimensional stability.

A lei geral de comunica????o eletr??nica de massa e a qualidade da programa????o televisiva

O presente artigo pretende analisar a quest??o da qualidade da programa????o na televis??o brasileira a partir da proposta de um novo marco regulat??rio para o setor de comunica????o social eletr??nica. Essa nova lei, entre outras disposi????es, ir?? regulamentar o artigo 221 da Constitui????o Federal, que trata dos princ??pios pelos quais o conte??do televisivo deve pautar-se. Com isso, define-se qualidade levando-se em considera????o dois aspectos: diversidade e ressalvas ?? liberdade de express??o, ambos previstos na Constitui????o Federal. A partir dessa conceitua????o, prop??e-se a instrumentaliza????o do controle social sobre o conte??do televisivo e a garantia de meios para a diversidade da programa????o. Com rela????o ao primeiro aspecto, recomenda-se a atua????o transparente de uma futura ag??ncia reguladora e a implementa????o de mecanismo de controle individual da programa????o. No que tange ?? diversidade, ressalta-se a import??ncia do fortalecimento das televis??es p??blicas e medidas governamentais no sentido de estimular a multiprograma????o propiciada pelo advento da tecnologia digital.