Marcadores nutricionais e inflamatórios e sua associação com a morbimortalidade em hemodiálise

Background: Malnutrition, inflammation and comorbidities are frequent in patients with chronic renal failure in hemodialysis (HD), contributing for morbidity and mortality. Aims: To evaluate the correlation between anthropometric, laboratory parameters, bioelectrical impedance (BIA) and inflammatory markers with the morbidity and mortality of patients in HD, as well as the impact of its alterations throughout 12 months. Methods: 143 patients of a dialysis facility in Northeast Brazil were evaluated throughout 18 months. Patients with more than 3 months on dialysis, older than 18 years, without amputation of hands and feet, were included in the study. We performed a clinical (subjective global assessment - SGA), anthropometric (BMI, percent of ideal weight, MAC, MAMC, MAMA, percent of fat mass and TSF), laboratory (albumin, creatinine, lymphocyte count as nutritional markers and CRP, IL-6 and TNF- as inflammatory markers) evaluation and BIA (reactance, phase angle and percent of body cell mass) at the beginning of study and after 3, 6 and 12 months of follow-up. The association between study variables and deaths and hospitalizations in 6 and 12 months was investigated. The variable with significance < 10% in the univariate analysis had been enclosed in a multivariate logistic regression analysis. We also investigated the risk of mortality and hospitalization associated with differences in measurements of the variables at baseline and six months later. Results: Patients were aged 52.2 ± 16.6 years on the average, 58% were male, and mean dialysis vintage was 5.27 ± 5.12 years. The prevalence of malnutrition varied from 7.7-63.6%, according to the nutritional marker. The variables associated with morbidity and mortality in 6 and 12 months had been creatinine ≤ 9.45 mg/dl, phase angle ≤ 4.57 degrees, BMI ≤ 23 kg/m2, age ≤ 64.9 years, reactance ≤ 51.7 ohms; Charlson´s index ≥ 4 and socioeconomic status ≤ 7. During six months of follow up, decrease in albumin was associated with significantly higher mortality risk. Conclusions: This study detected that the best predictors of morbidity and mortality between nutritional and inflammatory markers are phase angle, reactance, creatinine and BMI and that changes in albumin values over six 107 months provide additional prognostic information. The authors believe that parameters of BIA may detect early changes in nutritional status and emphasize that longitudinal studies with larger number of patients are necessary to confirm these data and to recommend BIA as a routine nutritional evaluation in HD patients

Estado nutricional antropométrico, composição corporal e pressão arterial em adolescentes

Os objetivos deste trabalho foram: (1) estimar as prevalências de excesso de peso e de gordura corporal, obesidade central e pressão arterial elevada (PAE) em adolescentes beneficiários do Programa Nacional de Alimentação Escolar (PNAE) da rede municipal de ensino de Natal-RN; (2) verificar a associação entre variáveis antropométricas e de composição corporal com a pressão arterial, a maturação sexual e a história familiar positiva de fatores de risco para doença cardiovascular (FRDCV); (3) comparar dois padrões de referência para classificação do excesso de peso em adolescentes; e (4) propor equações preditivas de massa gorda (MG) e massa livre de gordura (MLG) baseadas nos perímetros corporais. Trata-se de um estudo transversal, com 526 adolescentes beneficiários do PNAE, em Natal, Brasil. O tamanho da população de estudo foi definido por amostragem aleatória, em dois estágios, e ponderada segundo número de alunos de cada escola. No primeiro estudo, o excesso de peso foi determinado por Índice de Massa Corporal (IMC), a gordura corporal estimada por dobras cutâneas e a obesidade central por perímetro abdominal. A pressão arterial elevada foi classificada conforme a American Academy of Pediatrics. As prevalências foram apresentadas em valores relativos e efeito do desenho. Realizou-se uma análise fatorial para sintetizar o conjunto de variáveis antropométricas visando identificar fatores comuns. Extraíram-se dois fatores: (1) padrão excesso de adiposidade e (2) padrão adiposidade central elevada. Para avaliar a associação entre os padrões de adiposidade corporal com pressão arterial elevada, faixa etária, maturação sexual e história familiar de FRDCV utilizou-se a Razão de Chances e respectivo intervalo de confiança de 95% e regressão logística. No segundo estudo, calculou-se a sensibilidade e a especificidade do excesso de peso classificado segundo o IOTF e a World Health Organization WHO em relação ao excesso de adiposidade corporal; e a estatística Kappa para medir a concordância entre os dois padrões de referência. No terceiro estudo, foram elaborados modelos preditivos de MG e MLG com base em nove perímetros corporais, utilizando a bioimpedância Byodinamics 450 como padrão de referência. Para tanto foram selecionados 218 adolescentes eutróficos, segundo o IMC a partir do estudo transversal. As equações foram estimadas por regressão linear múltipla, considerando a idade e os perímetros corporais. Os resultados apontaram que 14,1% dos meninos e 15,7% das meninas tinham excesso de peso; 15,3% dos meninos e 11,6% das meninas tinham excesso de gordura corporal e dentre os meninos 14,3% tinham pressão arterial elevada e as meninas, 21,4%. Todos os efeitos do desenho foram inferiores a 2,5%. Nos meninos, o padrão excesso de adiposidade foi associado à história familiar positiva de FRDCV (ORajust=2,60; 1,09-6,22), maturação sexual (ORajust=2,92; 1,04-8,22) e PAE (ORajust=3,66; 1,34-9,94). Os meninos com 12 anos e mais apresentaram 6,1 vezes mais chance de apresentar padrão adiposidade central elevada do que os adolescentes com 10 a 11 anos (IC95% 2,32-16,04), assim como os púberes apresentaram 3,2 vezes este mesmo padrão em relação aos pré-púberes (IC95%1,14-8,85). A partir da comparação entre os dois padrões de referencia de classificação do excesso de peso por meio do IMC, observou-se que a sensibilidade foi de 79,3% para o critério IOTF e de 88,9% para WHO e a especificidade foi de 94,7% e 89,9%, respectivamente. O nível de concordância foi maior para o critério IOTF (Kappa=0,70 x Kappa=0,64). Em relação à construção das equações preditivas de gordura corporal, do total de 106 meninos e 112 meninas, foram desenvolvidas duas equações para estimar MG e duas para MLG, considerando o sexo. No sexo masculino, a equação para estimar a MG incluiu as variáveis idade, punho, quadril e perímetro abdominal (R2=0,552; AIC=416,04) e MLG, idade, punho e antebraço (R2=0,869; AIC=578,24). Enquanto que no feminino, MG foi estimada pelas variáveis punho, perímetro do abdômen, do quadril, da coxa proximal e da panturrilha (R2=0,838; AIC=415,36); e a MLG por idade, punho, perímetro do abdômen, do quadril e da panturrilha (R2=0,878; AIC=512,48). Conclui-se que os adolescentes tinham elevada prevalência de excesso de adiposidade corporal e de pressão arterial elevada. Tanto o padrão excesso de adiposidade quanto adiposidade central elevada constituem-se em padrões de risco. O padrão excesso de adiposidade foi associado à pressão arterial, história familiar positiva de FRDCV e maturação sexual em meninos. O critério IOTF mostrou-se menos sensível, mais específico, com maior nível de concordância e maior probabilidade de identificar corretamente o excesso de gordura corporal nos adolescentes avaliados. Quatro equações foram desenvolvidas para a estimativa da MG e MLG em adolescentes. As equações desenvolvidas para estimar a MG no sexo feminino e MLG para ambos os sexos apresentaram valores elevados de coeficiente de determinação ajustados e, portanto, são as preferenciais. Este estudo foi realizado com a participação de equipe multidisciplinar composta por professores da área de Nutrição, Endocrinologia Pediátrica, Estatística, Educação Física, discentes do Curso de Graduação em Nutrição e residentes em Pediatria

Estágio menopausal e níveis hormonais no desenvolvimento muscular e funcional em mulheres de meia idade: um estudo transversal

Introduction: Hypoestrogenism is the main characteristic of female aging. It promotes significant changes in body composition, both in fat mass as in lean body mass, leading to a decrease in muscle strength and physical performance. Objective: The aim of this study was to test whether menopausal status and hormone levels are associated with muscular strength and physical performance in middle-aged women. Methods: In a cross-sectional study it was collected sociodemographic data, gynecological history, anthropometric and biochemical measures in women aged 40 to 65 years in Parnamirim-RN. The menopause status (pre, peri and post menopause) was determined by menstrual history. All women underwent three dimensions of physical performance assessment: handgrip dynamometry, gait speed and chair stands test - Short Physical Performance Battery (SPPB). Categorical data were presented as absolute and relative frequencies. Quantitative data were showed as mean and standard deviation and the normality of distribution was verified with Kolmogorov-Smirnov (KS) test. Biochemical measures of estradiol and follicle-stimulating hormone (FSH) were transformed to log10. ANOVA with Tukey post-test for comparison of variables between the groups pre, peri and post-menopausal was performed and then multiple linear regression analyzes. Results: Two hundred and seventy eight women aged 50.2 (±5.58) years composed this study, being 50 women in premenopausal status (18%), 122 in perimenopausal (43.9%), and 106 postmenopausal stage (38.1%). The groups were different in age (p=0.001), marital relationship duration (p <0.001), number of pregnancies (p=0.001) and parity (p=0.001). Differences in biochemical measures were observed among the groups: estradiol (p<0.001), FSH (p<0.001), total cholesterol (p=0.001). There were no differences in gait velocity between menopausal status. Values in mean of grip strength decreased by postmenopausal women to perimenopausal and premenopausal ones (24.5 ± 5.1, 25.6 ± 5.4, 26.9 ± 4.9 for post-stage, pre and peri menopausas, respectively, p = 0.02) and the performance of chair stands test was better in premenopausal women compared with that in peri and postmenopausal status (p = 0.02). In multiple linear regression for muscle strength, the variables that remained were: age, estradiol and somatic symptoms measured by Menopause Rating Scale-MRS (R2=0.15). While for the xiv chair-stands test the predictors were number of births and FSH values (R2=0.04). Conclusion: There is a relationship between the stages of menopause and muscle performance in measures of grip strength and sit-up test and these are influenced by the fall of estrogens levels. Data suggest that the decrease in muscle strength and physical performance already appear in the transition to menopause stage, pointing to the need for more research in this area and appropriate preventive interventions

Métodos de avaliação nutricional para a suplementação oral com zinco em crianças pré-púberes não deficientes em zinco

Background: Zinc is an essential nutrient that is required for numerous metabolic functions, and zinc deficiency results in growth retardation, cellmediated immune dysfunction, and cognitive impairment. Objective: This study evaluated nutritional assessment methods for zinc supplementation in prepubertal nonzinc- deficient children. Design: We performed a randomised, controlled, triple-blind study. The children were divided into a control group (10% sorbitol, n = 31) and an experimental group (10 mg Zn/day, n = 31) for 3 months. Anthropometric and dietary assessments as well as bioelectrical measurements were performed in all children. Results: Our study showed (1) an increased body mass index for age and an increased phase angle in the experimental group; (2) a positive correlation between nutritional assessment parameters in both groups; (3) increased soft tissue, and mainly fat-free mass, in the body composition of the experimental group, as determined using bioelectrical impedance vector analysis; (4) increased consumption of all nutrients, including zinc, in the experimental group; and (5) an increased serum zinc concentration in both groups (p < 0.0001). Conclusions: Given that a reference for body composition analysis does not exist for intervention studies, longitudinal studies are needed to investigate vector migration during zinc supplementation. These results reinforce the importance of employing multiple techniques to assess the nutritional status of populations.

Métodos de avaliação nutricional para a suplementação oral com zinco em crianças pré-púberes não deficientes em zinco

Background: Zinc is an essential nutrient that is required for numerous metabolic functions, and zinc deficiency results in growth retardation, cellmediated immune dysfunction, and cognitive impairment. Objective: This study evaluated nutritional assessment methods for zinc supplementation in prepubertal nonzinc- deficient children. Design: We performed a randomised, controlled, triple-blind study. The children were divided into a control group (10% sorbitol, n = 31) and an experimental group (10 mg Zn/day, n = 31) for 3 months. Anthropometric and dietary assessments as well as bioelectrical measurements were performed in all children. Results: Our study showed (1) an increased body mass index for age and an increased phase angle in the experimental group; (2) a positive correlation between nutritional assessment parameters in both groups; (3) increased soft tissue, and mainly fat-free mass, in the body composition of the experimental group, as determined using bioelectrical impedance vector analysis; (4) increased consumption of all nutrients, including zinc, in the experimental group; and (5) an increased serum zinc concentration in both groups (p < 0.0001). Conclusions: Given that a reference for body composition analysis does not exist for intervention studies, longitudinal studies are needed to investigate vector migration during zinc supplementation. These results reinforce the importance of employing multiple techniques to assess the nutritional status of populations.

Influência da adição de resíduo de caulim nas propriedades tecnológicas de uma massa padrão de porcelanato produzido em escala industrial

VARELA, M. L. et al. Influência da adição de resíduo de caulim nas propriedades tecnológicas de uma massa padrão de porcelanato produzido em escala industrial. Cerâmica, v.55, n.334 p.209-215. 2009.ISSN 0366-6913.Disponível em: . Acesso em: 06 out. 2010.

Influência do lodo de ETE na massa para fabricação de cerâmica vermelha

The WTP produce many kinds of residue on your treatment stages, but the sludge is the more problematic from the final disposition point view. The actual rate of residue production deriving from technological evolution and the crescent population needs prevents the subtle equilibrium generation between consumption and recycling/reuse, creating problems of pollution resulting from inappropriate management of residues. Thus, is necessary achieve a new equilibrium between the grow from raw materials and energy and the residue generation. This equilibrium should be achieved by technical and economic feasibility of environmental supported models through recycling and reuse. The red ceramic industry stand out in residue absorption question as raw material due their clay mass heterogeneity, constituted by clay minerals and non-clay minerals with wide mineralogical variation, allowing residue inclusion which act like plastic or non-plastic materials, contributing to retain heavy metals contained in residues in the vitreous mass formed during the burning of the ceramic bodies. This work propose the study of the influence of incorporation of 25 wt.% sludge from wastewater treatment plant, according preliminary results, in the mass to produce ceramic bodies. The raw materials was characterized through chemical composition analyses by XRF, mineralogical analyses by XRD, thermal analyses by TG and DTA, Atterberg limits and thermodilatometry. Subsequently was composed the mass with 75 wt.% of clay and 25 wt.% of dried wastewater sludge from UFRN WWTP. Samples with 6,0 x 2,0 x 0,5 cm was produced with unidirectional compacting under pressure of 20MPa and burned in temperatures between 950 and 1,200ºC. After fired, the ceramic bodies have been submitted to physical and mechanical analyses through the measure of firing shrinkage, water absorption, density, apparent porosity and flexural strength; crystallographic analyses through XRD and microstructure analyses by SEM. The technological properties obtained was satisfactory to production of roof tiles with 25 wt.% at 1,200 ºC, but the production of others products at lower temperatures was not feasible

Efeito da adição de carbonatos em formulação de massa para revestimento cerâmico utilizando matérias-primas do Piauí

Piauí state is a major producer of traditional red ceramic burning as bricks, tiles and ceramic tiles, with its main production center located in the city of Teresina. The state has large reserves of raw materials that can be used in the ceramic coating as clays, quartz, talc and carbonates. However, in the preparation of ceramic bodies using only a mixture of clays with different characteristics. The study aims to evaluate the effect of adding two types of carbonates in the ceramic semiporous mass coating produced in Piauí and then to verify the potential use of these carbonates as supplementary raw material product manufactured or the feasibility of obtaining a ceramic plate that meets the specifications for the porous coating. For this, were characterized the ceramic Piauí coating mass, a calcitic carbonate and a dolomitic, were made in the levels of 2, 4, 8, 16, and 32%. The masses were formed by pressing and burneds in two environments: a laboratory furnace (1080°C, 1120°C, 1140°C, and 1160°C) and an industrial furnace (1140°C). Then, following tests of linear shrinkage water absorption, apparent porosity, bulk density and flexural strength. Furthermore, the fired specimens were tested for their macrostructure and microstructure. The results showed the possibility of using the carbonate in ceramic mass flooring produced in Piauí, as added in small proportions improved dimensional stability and increased mechanical strength of ceramics pieces. It also proved itself possible to produce porous coating when added in higher levels

Estudo de massa cerâmica triaxial visando à otimização do ciclo de queima da indústria de cerâmica 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.

Adição de subprodutos da cinza da casca de café (coffea canephora) em massa cerâmica para porcelanato

To produce porcelain tiles fluxing agents are used in order to obtain a liquid phase during firing. This liquid phase fills the pores decreasing porosity, water absorption and contributes to material densification. In the porcelain tiles industry, feldspar is the main flux material used, with quantities ranging between 35 and 50%. Studies focus on the discovery of materials with flux characteristics that can reduce the consumption of feldspar by porcelain tiles industry. In this context, the coffee husk ashes, a residue obtained when coffee husks are burned to produce heat for the dryers during the processing of the green fruit, have as main chemical constituents potassium, calcium and magnesium, giving them characteristics of fluxing material. Brazil is the largest coffee producer in the world and is responsible for over 30% of the world s production. In this work a physical treatment of coffee husk ash was carried out in order to eliminate the organic matter and, after this, two by-products were obtained: residual wastes R1 and R2. Both residues were added separately as single fluxes and also in association with feldspar in mixtures with raw materials collected in a porcelain industry located in Dias d Ávila-Ba. The addition of these residues aimed to contribute to the reduction of the consumption of feldspar in the production of porcelain tiles. Specimens were produced with dimensions of 60 mm x 20 mm x 6 mm in an uniaxial die with compacting pressure of 45 MPa. The samples were heated to a temperature of 1200 °C, for 8 minutes. Tests were performed to characterize the raw materials by XRF, XRD, particle size analysis, DTA and TGA and, additionally, the results of the physical properties of water absorption, apparent porosity, linear shrinkage, density, dilatometry, flexural strength and SEM of sintered body were analyzed. Additions of less than 8% of the residue R1 contributed to the decrease of porosity, but the mechanical strength of the samples was not satisfactory. Additions of 5% the R2 residue contributed significantly to decrease the water absorption and apparent porosity, and also to increase the mechanical strength. Samples with addition of feldspar associated with the R2 residue, in proportions of 6.7% of R2 and 6.7% of feldspar, led to results of water absorption of 0.12% and mechanical strength of 46 MPa, having parameters normalized to the manufacture of porcelain stoneware tiles

Gênero ou sexualidade?: (re) produção das identidades homoeróticas masculinas no cinema de massa

Homosexuality has been gaining strength in Cinema from the late twentieth century, when there is a dissemination of freedoms around the peripheral or marginal sexualities. Based on this assumption, it was formulated in the dissertation work, an analysis of the relationship between Cinema and Sexuality in order to understand, describe, reflect and analyze possible changes around the performative behaviors of male homosexual from the introduction of them in film production, arising from the mass culture industry. These productions are located in three different decades. In this case, the Cinema has not only the reproductive character of realities, but also a producing agent and consolidating them. The methodology applied was discourse analysis of three film works, namely La Cage aux Folles (1978), In & Out (1997) and Boat Trip (2002). The image, research object of this work, is developed by a mass culture that will produce mass identities which is characterized by crystallization of clichés around the gay world

Efeito da introdução de resíduo de cinza de forno cerâmico em massa para cerâmica estrutural

The red ceramics and structural ceramics, as they are known, include ceramic materials made by blocks of seals and structures, bricks, tiles, smail flagstones manacles, rustic floors and ornamental materials. Their fabrication uses raw material such as clay and clay sites, with some content of impurity. It has good durability and mechanical strength to compression, low cost, making it one of the mainly used materials in civil engineering. The incorporation of many industrial activities residue to ceramic products is a technological alternative for reducing the environmental impact caused by its carefree disposal. This incorporation can promote chemical change and inertness of metals from residue, by fixation in the glassy phase of ceramic during the burning stage. The main aim of this project is to study the technical feasibility of the addition of ceramic oven ash into formulations of mass for structural ceramics. In this project two kinds of clay (plastic and non-plastic) were used, as well as the ash from firewood used in the process of burning of structural ceramics. A group of experiments was outlined, which permitted the evaluation of the influence of the burning cycle in different temperatures of the ash content in formulations for ceramic blocks through technological properties, mechanical behavior and microstructure. Five samples were processed of each one of the masses of plastic and non-plastic clay without addition of ash and with addition of ash on the percentages of 10 % and 20 %, for temperatures of 850 °C, 950 °C, 1050 °C and 1150 °C, obtained through sinterization process. Among the studied compositions, the one which presented best performance was the mass of clay with 10 % of ash, at temperature of 1150 °C, with the smallest absorption of water, the smallest apparent porosity, specific apparent mass a bit over the others and greatest mechanical resistance to flexion. The composition made confirmed the technical feasibility of the use of ash in the mass for structural ceramics with maintenance of its necessary characteristics for its purposes

Aproveitamento de resíduos de cinza da cana de açúcar em massas cerâmicas

This study aimed to investigate the use of cane sugar ashes from small-scale stills of Eunápolis region, state of Bahia, in pottery mass that can be developed as porcelain stoneware. Bahia is the second largest producer of rum distillery in Brazil. In the production of rum is produced residue called bagasse, which is used to generate electricity in Power plants and in the distillery itself, generating ashes as residue, which is played in nature, causing environmental damage. We studied 5 (five) formulations of 0% 10% 20%, 30% and 40% by weight of the ash, without ignition and 3 (three) formulations of 10%, 20% and 30% with gray ash temperature of 1250ºC. The formulation at 0% by weight of ash was used for a comparison between the traditional mass of porcelain stoneware and the masses with the addition of ash calcined, replacing feldspar. The percentage by weight of kaolin and of Clay was kept the same, 30%, and all raw materials were derived from the state of Bahia. The samples were made in uniaxial array with dimensions of (60 x 20 x 5) mm and compressed to a pressure of 45 MPa. Assays were performed to characterize the raw by X-ray fluorescence, X-ray diffraction, ATD and ATG and Dilatometric analysis. The samples were sintered at temperatures of 1100°C, 1150°C, 1200°C and 1250°C, for the specimens with the ashes without ash and 1150° C and 1200° C for specimens with the gray level of calcined 60 minutes. and then we made a cooling ramp with the same rate of warming until reach ambient temperature. The sintered bodies were characterized by water absorption, porosity, linear shrinkage, bending strength and XRD of the fracture surface and the results analyzed. It was proven, after results of tests performed, that it is possible to use the ash residue of sugar cane bagasse on ceramic coating with the addition of up to 10% wt of the residue ash

Modelagem numérica de escoamento em padrão anular com transferência de calor e massa

Annular flow is the prevailing pattern in transport and energy conversion systems and therefore, one of the most important patterns in multiphase flow in ducts. The correct prediction of the pressure gradient and heat transfer coefficient is essential for optimizing the system s capacity. The objective of this work is to develop and implement a numerical algorithm capable of predicting hydrodynamic and thermal characteristics for upflow, vertical, annular flow. The numerical algorithm is then complemented with the physical modeling of phenomena that occurs in this flow pattern. These are, turbulence, entrainment and deposition and phase change. For the development of the numerical model, axial diffusion of heat and momentum is neglected. In this way the time-averaged equations are solved in their parabolic form obtaining the velocity and temperature profiles for each axial step at a time, together with the global parameters, namely, pressure gradient, mean film thickness and heat transfer coefficient, as well as their variation in the axial direction. The model is validated for the following conditions: fully-developed laminar flow with no entrainment; fully developed laminar flow with heat transfer, fully-developed turbulent flow with entrained drops, developing turbulent annular flow with entrained drops, and turbulent flow with heat transfer and phase change

Estudo de formulação de massa para aplicação em placas cerâmicas

The sector of civil construction is strongly related to the red ceramic industry. This sector uses clay as raw material for manufacturing of various products such as ceramic plates. In this study, two types of clay called clay 1 and clay 2 were collected on deposit in Ielmo Marinho city (RN) and then characterized by thermogravimetric analysis (TG/DTG), differential thermal analysis (DTA), X-ray diffraction (XRD), X-ray fluorescence (XRF), rational analysis and particle size distribution and dilatometric analyses. Ceramic plates were manufactured by uniaxial pressing and by extrusion. The plates obtained by pressing were produced from the four formulations called 1, 2, 3 and 4, which presented, respectively, the following proportions by mass: 66.5% clay 1 and 33.5% clay 2, 50% clay 1 and 50% clay 2, 33.5% clay 1 and 66.5% clay 2, 25% clay 1 and 75% clay 2. After firing at 850, 950 and 1050 °C with heating rate of 10 °C/min and soaking time of 30 minutes, the following technological properties were determined: linear firing shrinkage, water absorption, apparent porosity, apparent specific mass and tensile strength (3 points). The formulation containing 25% clay 1 produced plates with most satisfactory results of water absorption and mechanical resistance, because of that it was chosen for manufacturing plates by extrusion. A single firing cycle was established for these plates, which took place as follow: heating rate of 2 °C/min up to 600 ºC with soaking time of 60 minutes, followed by heating using the same rate up to 1050 ºC with soaking time of 30 minutes. After this cycle, the same technological properties investigated in the plates obtained by pressing were determined. The results indicate (according to NRB 13818/1997) that the plates obtained by pressing from the mixture containing 25 wt% clay 1, after firing at 1050 °C, reach the specifications for semi-porous coating (BIIb). On the other hand, the plates obtained by extrusion were classified as semi-stoneware (group AIIa)