Currently 884 million people worldwide are living without access to an improved source of drinking water (WHO/UNICEF, 2011). Piped-water on premises is the ultimate goal of World Health Organization (WHO) due to the ability to treat all of the water and distribute it safely in pressurized pipes. However, Household Water Treatment and Safe Storage (HWTS) is an option for improving the quality of drinking water where that infrastructure is not yet developed, especially where there is a risk of recontamination between point of collection and point of use (Clasen, 2006). This study analyzed one such HWTS, the ceramic pot water filter. The study compared the hydraulic properties of the FilterPure (FP) and Potters for Peace (PFP) ceramic pot filters through a thirteen-month field study in the Dominican Republic and laboratory studies at the University of South Florida. In the field study 55 filters were tested for first hour flow rate and hydraulic conductivity. Eight first hour flow rate tests were conducted in the field on one month intervals during months 7- 13. FP filters had an average first hour flow rate of 553 ml/hr and PFP Filters had a first hour flow rate of 395 ml/hr. No significant change in first hour flow rate was observed over time in FP filters. PFP experienced an average increase of 31 ml/hr per month during the seven-month testing period. Falling head tests were conducted on four filters in the laboratory and the flow rate was modeled to determine hydraulic conductivity. Hydraulic conductivity values for FP filters ranged from k = 0.0495 - 0.0831 cm/hr and for PFP filters ranged from k = 0.0136 - 0.0389 cm/hr. Eight out of 29 (26%) Potters for Peace filters in the field had first hour flow rates of less than 250 ml/hr by month nine of the study and had to be replaced and removed from the study. In total 24 of 55 (44%) filters (8 FP and 16 PFP) had to be removed from the study due to several reasons discussed in this thesis.

Darbe nagrinėta Šalčios upė, jos tyrimui buvo pasirinkti 24 vandens mėginių ėmimo taškai, kuriuose nustatytos tokių biogeninių medžiagų koncentracijos: amonio azoto, nitratų azoto, nitritų azoto, pH ir bendrojo fosforo. Pagal gautus duomenis iš hidrometeorologijos tarnybos nustatyta debito priklausomybė nuo klimato veiksnių. Atsižvelgiant į fizines-geografines sąlygas ir įvertinus maksimalius metinius kritulius bei vienos liūties kritulius, nustatytas susidarančio nuotėkio pobūdis. Išanalizavus gautus natūrinių tyrimų rezultatus, nustatyti veiksniai, lemiantys didžiausią upės vandens taršą. Pagal gautus duomenis nustatyta upės ekologinė būklė. Darbą sudaro 6 dalys: įvadas, mokslinės literatūros apžvalga, tyrimo objektas ir metodika, tyrimų rezultatai, išvados, literatūra. Darbo apimtis: 69 p. teksto be priedų, 34 iliustracijos, 9 lentelės, 65 literatūros šaltiniai. / The scientific literature related to the issue and research methodology is discribed in this master work. In the work was analyzed Šalčia’s River, there were selected 24 sampling points where was detected concentrations of these nutrients: ammonium nitrogen, nitrate nitrogen, nitrite nitrogen, pH, and total phosphorus. According to the data obtained from the Hydrometeorological Service there were determined flow dependence on climatic factors. In view of the physical-geographical conditions and the evaluation of the maximum annual rainfall and the rainfall of a storm there were generated runoff patterns. The analysis of the results obtained during the experimental helped to determine the factors leading to maximum river water pollution. According to the data obtained there was found ecological status of the river. The work consists of six parts: introduction, literature review, research and methodology, results, conclusions and references. Work size: 69 p. text, 34 figures, 9 tables, 65 references.

The work started with the clinical observations in patients working in buildings with indoor air problems. Signs of seborrhoeic dermatitis, erythematous facial skin conditions and itching conditions on the trunk were noted. Another point of departure was the attribution of facial skin symptoms to VDT work by patients. A questionnaire-based prevalence study of symptoms compatible with the Sick Building Syndrome (SBS) and facial skin symptoms in 4,943 office workers formed the basis for two case referent studies, one focusing on SBS, the other on facial skin symptoms in VDT workers. The prevalence of SBS was three times higher in women than men. The prevalence was higher in young persons and in atopies. Facial skin symptoms showed the same pattern. Psychosocial work load, paper and VDT work were also risk indicators for SBS and for skin symptoms. The symptom excess in women was analyzed with reference to differences in biological or acquired risks and different illness and reporting behaviour. In spite of inequalities in social conditions at home and at work and differences in physical working conditions, these differences could only explain a small part of the gender difference. The odds ratio for SBS in women was lowered from 3.4 in the crude analysis to 3.0 in the multivariate analysis. Effect modification was in most cases stronger in men and the clinical validation of the questionnaire refuted the hypothesis that women over-report symptoms. The results indicate that the gender difference in symptom prevalence is part of a general pattem common to psychosomatic illnesses. In the case referent study of SBS, atopy, psychosocial work load, buildings built or renovated after 1977, the presence of photocopiers and a low outdoor air flow rate were risk indicators. The association between air quality and the occurrence of SBS symptoms was demonstrated by a flow-response relation between the outdoor air flow rate and SBS symptoms. In the case referent study of skin symptoms in VDT work, psychosocial work load, electric background fields, the presence of fluorescent lights with plastic shields and low cleaning frequency were risk indicators. The clinical findings in the two case groups and their referents supported the applied relevance of the studies. Compared with the referents, the SBS cases had more work- related facial erythema, seborriioeic dermatitis and general pruritus, while skin symptom cases, had more work-related facial erythema than their referents. The results show that SBS symptoms and facial skin symptoms have a multifactorial background with constitutional, psychosocial and physical risk indicators. As the indoor air quality is a determinant of SBS symptoms, and the building itself is but one source of indoor air pollution, it is suggested that the name Sick Building Syndrome (SBS) be replaced by Indoor Air Syndrome (IAS). / <p>Diss. (sammanfattning) Umeå : Umeå universitet, 1994, härtill 5 uppsatser.</p> / digitalisering@umu

Thesis (Ph.D.); Submitted to Iowa State Univ., Ames, IA (US); 19 Dec 2004. / Published through the Information Bridge: DOE Scientific and Technical Information. "IS-T 2134" Meera Jay Desai. US Department of Energy 12/19/2004. Report is also available in paper and microfiche from NTIS.

Submitted by Deyse Queiroz (deysequeirozz@hotmail.com) on 2018-06-06T14:21:51Z No. of bitstreams: 1 MARIA DE ANDRADE DOLORES CARNEIRO NÓBREGA - DISSERTAÇÃO PPGSA PROFISSIONAL 2016..pdf: 2770347 bytes, checksum: 8ae5f9e2adb84ae0d301b70b2e4a2b13 (MD5) / Made available in DSpace on 2018-06-06T14:21:51Z (GMT). No. of bitstreams: 1 MARIA DE ANDRADE DOLORES CARNEIRO NÓBREGA - DISSERTAÇÃO PPGSA PROFISSIONAL 2016..pdf: 2770347 bytes, checksum: 8ae5f9e2adb84ae0d301b70b2e4a2b13 (MD5) Previous issue date: 2016-09-03 / A Bacia Incremental do Rio Piancó está inserida na Bacia Hidrográfica do rio Piancó Piranhas Açú. Seu curso d’água principal, o rio Piancó, tem importância estratégica para o desenvolvimento regional pois é um manancial vital para o desenvolvimento de várias atividades socioeconômicas realizadas ao longo do seu curso. O trecho possui sistemas de adutora que abastece dezoito localidades. Este trabalho teve como objetivo apresentar e discutir o domínio das águas do rio Piancó, no trecho com a vazão regularizada até sua foz, partindo do estudo mais geral da bacia do rio Piancó, nos aspectos Fisiográficos, pedológico, capacidade de uso do solo, formas de uso e ocupação do solo e características e informações hidrológicas. De forma específica, sobre o trecho do rio regularizado, nos aspectos da dominialidade, disponibilidade e a qualidade da água decorrentes dos diversos usos, considerando a variabilidade climática ocorrida ao longo do tempo, com a consequente variação do volume armazenado no sistema de reservatórios e sua influência nas diferentes forma de uso da água ao logo do rio regularizado. Pode-se concluir que a qualidade de água com relação aos parâmetros analizados não houver alteração na temperatura no interior da bacia ,Condutividade eletrica ocorrem um pequeno aumento nos seus valores, porem dentro da faixa preconizada pela legislação,Turbidez houve um leve aumento apenas nos periodo chuvoso mantendo-se dentro das faixa aceitavel no restante do tempo,Oxigênio Dissolvido de modo geral ocorreu um pequeno aumento em periodo de estiagem ocasionado pela alevação no nível de altrofização com intensa atividade de fotosintese.Também foi possível concluir que o domínio das águas parte da bacia é de domínio estadual que tem como orgão gestor AESAA ocorrência de vazões máximas (cheias) está condicionada a vazão de sancria dos sistemas de reservatorio, em menor proporção da formação de cheias na BHIRP associada a ocorrencia de chuvas intensas na area da bacia.Entretanto a maior variação até 400 anos de periodo de recorrencia com vazões cheias atingindo 900m3 /sAs vazões mínimas estão condicionadas a vazão de regularização na maior parte do tempo principalmente no periódo de estiagem ficando as vazões de referência Q7/10 e Q 90 com valores de 1,087 e 3,689 respectivamente. / The Piancó River Incremental Basin is inserted in the Piancó Piranhas Açú River Basin. Its main watercourse, the Piancó River, has strategic importance for regional development since it is a vital source for the development of various socioeconomic activities carried out along its course. Its main watercourse, the Piancó River, has strategic importance for regional development since it is a vital source for the development of various socioeconomic activities carried out along its course. The section has systems of adductor that caters eighteen localities. The objective of this work was to present and discuss the domain of the Piancó river waters, in the section with the regularized flow up to its mouth, starting from the more general study of the Piancó river basin, in the Physiographic, pedological, Of soil use and occupation and hydrological characteristics and information. Specifically, on the part of the regularized river, in terms of the dominance, availability and quality of the water resulting from the various uses, considering the climatic variability occurred over time, with the consequent variation of the volume stored in the reservoir system and its Influence on the different forms of water use to the regularized river logo. It can be concluded that the water quality in relation to the analyzed parameters does not change the temperature inside the basin, Electrical conductivity occurs a small increase in its values, however within the range recommended by the legislation, Turbidity there was a slight increase only in the period Rainy season keeping within acceptable range for the rest of the time, Dissolved Oxygen in general occurred a small increase in drought period caused by the elevation in the level of altrophization with intense photosynthesis activity. It was also possible to conclude that the domain of the water part of the basin is of state domain that has as its managing organ AESAA occurrence of maximum flows (floods) is conditioned to the flow of sancria of the reservoir systems, to a lesser proportion of the flood formation in the associated BHIRP The occurrence of intense rains in the area of the basin. However, the greatest variation up to 400 years of recurrence period with full flow rates reaching 900m3 / s. The minimum flows are conditioned to the flow of regularization most of the time mainly in the dry season, leaving the flows of Reference Q7 / 10 and Q90 with values of 1.087 and 3.689 respectively.

[pt] O setor elétrico brasileiro é fortemente dependente da energia hidrelétrica e a predição acurada das séries de vazões é essencial para o planejamento e gestão de risco. Recentemente, os modelos híbridos, que combinam técnicas de previsão e pré-processamento de dados, têm se destacado. Entretanto, na literatura, não há consenso sobre a superioridade de previsão destes modelos em relação aos tradicionais (puros). Este trabalho visa contribuir para literatura com a avaliação de performance de previsão e a adequabilidade de modelos puros e híbridos para séries mensais estacionárias e não estacionárias de vazões. Para isso, foram construídos modelos usando as técnicas de previsão de Redes Neurais Artificiais e ARIMA acoplados com as técnicas de pré-processamento de dados Singular Spectrum Analysis (SSA) e Seasonal and Trend decomposition based on Loess (STL). Como resultado, este estudo mostra para a série de Belo Monte (estacionária) os modelos puros obtiveram um melhor desempenho, já para a série de Sobradinho (não estacionária) os modelos híbridos foram os melhores. / [en] The Brazilian electricity sector is strongly dependent on hydropower and the accurate prediction of streamflow series is essential for planning and risk management. Recently, hybrid models, which combine prediction and data preprocessing techniques, have stood out. However, in the literature there is no consensus on the predictive superiority of these hybrid models versus their pure version. This paper aims to contribute to the literature with the evaluation of prediction performance suitability of pure and hybrid models for monthly stationary and non - stationary series of streamflow. For this, models were constructed using Artificial Neural Network and ARIMA forecasting techniques coupled with the Singular Spectrum Analysis (SSA) and Seasonal and Trend decomposition based on Loess (STL) data pre-processing techniques. As a result, this study shows that pure models obtained a better performance for the Belo Monte (stationary series), already hybrid models were the best for the Sobradinho (non-stationary series).

Combler une perte osseuse est une nécessité fréquente en chirurgie. L’usage d’implants biocéramiques est limité, conduisant au delà de quelques cm3, inaccessibles à l’ostéogénèse, à une hétérogénéité intrinsèquement fragile et une vascularisation interrompue. Les biomatériaux hybrides sont une solution. Ensemencée, la céramique est mise en culture en bioréacteur, un fluide y circulant afin d'alimenter les cellules et d’évacuer leurs déchets.L’étude porte sur une céramique en phosphate de calcium dont l’architecture interne consiste en pores sphériques interconnectés de quelques centaines de microns de diamètre. Le choix du débit et de l'écoulement à travers ce matériau reste jusqu’ici empirique. Pour optimiser la culture, il s'avère cependant nécessaire de savoir les déterminer en tout point afin de pouvoir les optimiser et les reproduire et, à terme, d'optimiser le choix de la biocéramique.L'étude numérique s'impose car les grandeurs physiques finales recherchées (vitesses et pressions locales) ne sont pas mesurables sur la structure microscopique. Or, ces grandeurs optimisées permettent de définir les grandeurs d'entrée optimales. Le protocole débute par une modélisation de la microstructure et le calcul de la taille du VER afin d'identifier la perméabilité intrinsèque du milieu. Une analyse statistique de la répartition des contraintes tangentielles en fonction des grandeurs moyennes homogénéisées permet ensuite d'identifier les paramètres d'entrée optimaux dans le VER. Finalement, une optimisation globale de la résolution des équations de Navier-Stokes sur la structure homogénéisée permet de définir le paramètre final, à savoir le débit de contrôle du bioréacteur. / Repairing a bone loss is a frequent need in orthopaedic surgery. Though now much developed the use of bioceramic implants is limited: a bulk greater than a few cm3 does not allow a complete osteogenesis. So an intrinsic brittle heterogeneity remains with an interrupted vascularization. Hybrid biomaterials are a solution. Seeded ceramics are cultured in a bioreactor, a fluid flowing through the material to feed the cells and to clear their waste out.This study focuses on a calcium phosphate ceramic whose internal architecture consists of spherical interconnected pores of a few hundred microns in diameter. The choice of the flow rate or other flow parameters through the material remains far empiric. To optimize the cell culture, it is however necessary to know how to determine them at any point in order to optimize and reproduce them and eventually to optimize the choice of the bioceramic.A numerical study is necessary because the final desired physical parameters (local velocities and pressures) are not measurable on a microscopic structure. However, these quantities are used to define the optimal input values. The protocol begins in modelling the microstructure and determining the size of the representative elementary volume (REV) in order to identify intrinsic permeability of the material. A statistical analysis of the distribution of shear stresses based on homogenized average values then leads to identify optimal input parameters in the REV. Finally, a global optimization of solving of the Navier-Stokes equations on the homogenized structure leads to define the final parameter, namely the flow of control of the bioreactor.

Made available in DSpace on 2016-06-02T20:18:25Z (GMT). No. of bitstreams: 1 6667.pdf: 1196973 bytes, checksum: 676ef679729a161c455a82783b16955a (MD5) Previous issue date: 2015-02-27 / Financiadora de Estudos e Projetos / The peak expiratory flow (PEF) is a simple and objective method that evaluates primarily the proximal airways caliber. The ease of handling and low cost of portable PEF meters have become its frequent use, however few studies have analyzed the agreement of the obtained values in different equipment, as well as compared its reference values, which justifies the Study I, which had as its objective to compare the obtained values, analyze the agreement of three portable PEF meters and check if the reference values that accompany these devices are appropriate for the population studied. 168 healthy individuals were evaluated, of both genders, in the age group of 20 to 80 years, who underwent PEF measurements in Mini-Wright®, Assess® and Air Zone® meters; then, the obtained values were compared to predict proposed by Leiner et al. (1963) and Nunn and Gregg (1989). The statistical analysis was performed using the Kolmogorov-Smirnov test, ANOVA, Wilcoxon test, Spearman's correlation test and Bland-Altman s agreement test, with a significance level of 5%. Significant differences were found in the PEF obtained values between Mini-Wright® and Assess® meters in both genders, between the Air Zone® and Assess® meters only in men, and between Mini-Wright® and Air Zone® meters only in women; and the PEF predict values in the three devices were considered significantly higher than those obtained in both genders. Moderate significant correlations were found between the obtained and predict values in men and women, but there was no agreement between the PEF obtained values in the meters, due to the great variation in the limits of agreement and large interindividual variation. It was concluded that the obtained values in the three meters are not interchangeable and the predicted values overestimated the obtained, indicating its inconsistency for the sample studied, that stimulated the realization of Study II, which aimed to establish PEF reference values for adults and elderly from Southeast region of Brazil based on the obtained values of three portable meters: Mini-Wright®, Assess® and Air Zone®. 373 healthy individuals were evaluated, of both genders, aged 20 to 80 years, who underwent PEF measurements in Mini-Wright®, Assess® and Air Zone® meters. The statistical analysis was performed by multiple linear regression analysis by stepwise selection method to determine the explicative variables and were tested three different models: using variable unit, logarithmic and adjust by age; and then the paired t-test was applied to compare the obtained values with predict by new model and to check the validation of the proposed model, with a significance level of 5%. Of the models tested, adjust by age showed the best agreement and the equations varied according to the meter and the coefficients age, corporal mass, height and body mass index (BMI) explained more than 90% variation in PEF. In the comparison of obtained values with those proposed by new model, no significant difference was found, confirming the validation of equations proposed in the meters. Therefore, equations of PEF were established for adults and elderly from Southeast region of Brazil, separated by gender and for each meter evaluated: Mini-Wright®, Assess® and Air Zone® considering the inadequacy of the common use of an equation for the three meters used. These equations enable the correct interpretation of PEF values in clinical practice. / O pico de fluxo expiratório (PFE) é um método simples e objetivo que avalia primariamente o calibre das vias aéreas proximais. A facilidade no manuseio e o baixo custo dos medidores portáteis de PFE tornaram seu uso frequente, entretanto, poucos estudos analisaram a concordância dos valores obtidos em diferentes equipamentos, bem como compararam seus valores de referência, o que justifica a realização do Estudo I, que teve como objetivo comparar os valores obtidos e analisar a concordância de três medidores portáteis de PFE e verificar se os valores de referência que acompanham esses aparelhos são adequados para a população estudada. Foram avaliados 168 indivíduos saudáveis, de ambos os gêneros, na faixa etária de 20 a 80 anos, que realizaram medidas de PFE nos medidores Mini-Wright®, Assess® e Air Zone®; os valores obtidos foram então comparados aos previstos propostos por Leiner et al. (1963) e Nunn e Gregg (1989). A análise estatística foi realizada pelos testes Kolmogorov-Smirnov, ANOVA, teste de Wilcoxon, correlação de Spearman e análise de concordância de Bland-Altman, com nível de significância de 5%. Constatou-se diferença significativa nos valores de PFE obtidos entre os medidores Mini- Wright® e Assess® em ambos os gêneros, entre o Air Zone® e o Assess® apenas nos homens e entre o Mini-Wright® e o Air Zone® somente nas mulheres; e os valores previstos de PFE nos três aparelhos foram considerados significativamente maiores que os obtidos em ambos os gêneros. Correlações moderadas significativas foram encontradas entre os valores obtidos e previstos em homens e mulheres, porém não se verificou concordância entre os valores de PFE obtidos nos medidores, devido à grande variação dos limites de concordância e grande variação interindividual. Concluiu-se que os valores obtidos nos três medidores não são intercambiáveis e que os valores previstos superestimaram os obtidos, indicando sua inconsistência para a amostra estudada, o que impulsionou a realização do Estudo II, que objetivou estabelecer valores de referência de PFE para adultos e idosos da região Sudeste do Brasil baseados nos valores obtidos de três medidores portáteis: Mini-Wright®, Assess® e Air Zone®. Foram avaliados 373 indivíduos saudáveis, de ambos os gêneros, na faixa etária de 20 a 80 anos, que realizaram medidas de PFE nos medidores Mini- Wright®, Assess® e Air Zone®. A análise estatística foi realizada através da análise de regressão linear múltipla pelo método de seleção stepwise para determinar as variáveis explicativas, e foram testados três modelos diferentes: utilizando a unidade da variável, logarítmico e ajuste pela idade; em seguida, o teste t pareado foi aplicado para comparar os valores obtidos com os previstos pelo novo modelo e assim verificar a validação do modelo proposto, com nível de significância de 5%. Dos modelos testados, o ajuste pela idade mostrou a melhor concordância e as equações variaram de acordo com o medidor, sendo que os coeficientes idade, massa corporal, estatura e índice de massa corporal (IMC) explicaram mais de 90% da variação do PFE. Na comparação dos valores obtidos com os previstos pelo novo modelo, não foi encontrada diferença significativa, comprovando a validação das equações propostas nos medidores. Portanto, equações de PFE foram estabelecidas para adultos e idosos da região Sudeste do Brasil, separadas por gênero e para cada medidor avaliado: Mini-Wright®, Assess® e Air Zone®, considerando a inadequação do uso comum de uma equação para os três medidores utilizados. Essas equações possibilitam a interpretação correta dos valores de PFE na prática clínica.

Made available in DSpace on 2015-03-26T13:23:24Z (GMT). No. of bitstreams: 1 texto completo.pdf: 1691186 bytes, checksum: 56494ab13d1dba2592f6de2920653a56 (MD5) Previous issue date: 2009-07-13 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The implantation of the National Water Information System (SNIRH) created by the Law nº 9.433/97 requires, for its structure, the use of computational tools that allow the databases creation, necessary for planning and management of water resources. To the knowledge of water availability and hydraulic structures design is necessary to quantity the flow rate at any position of the stream, which is obtained from the use of regionalization methods. The present work aimed at developing a computational system for regionalization study of the minimum, maximum and average flow, the regularization curves and the permanence curve. The flow regionalization methods considered were: traditional, dimensionless curve and mass conservation. The database obtained from the National Water Agency (ANA) and encoded on Otto Pfafstetter System was integrated to the software to acquire automatically the watershed characteristics. Also, it was used web services to the importation of descriptive data and station fluviometric data, climate characteristics associated with watershed and the historical flow rate data series from the &#8220;Hidroweb&#8221; system. The developed software was called &#8220;Computer System for the Flow Rate Regionalization" (SisCoRV) and was applied to Paracatu river basin to check their functionalities. In the case study, the SisCoRV had a good interaction with the Internet, ease delineation of homogeneous regions, efficiency in applying the regionalization methodology and ability to feed the ANA database. / A implantação do Sistema Nacional de Informações sobre Recursos Hídricos (SNIRH), criado pela Lei 9.433/97, requer para a sua estruturação a utilização de ferramentas computacionais que possibilitem a criação de bancos de dados necessários para o planejamento e a gestão dos recursos hídricos. Para o conhecimento da disponibilidade hídrica e o dimensionamento de obras hidráulicas é essencial a quantificação de vazões, obtidas a partir da utilização de metodologias de regionalização. Com esse intuito, o presente trabalho teve por objetivo desenvolver um modelo computacional que possibilite a realização da regionalização das vazões mínimas, máximas e médias e das curvas de regularização e de permanência. Os métodos de regionalização de vazões contemplados foram: tradicional, da curva adimensional e da conservação de massas. Foi integrada ao software a base hidrográfica ottocodificada da Agência Nacional das Águas (ANA), que propicia a obtenção automática das características físicas das bacias e empregados web services que permitem a importação dos dados descritivos das bacias e das estações fluviométricas, das características climáticas associadas às bacias hidrográficas e das séries históricas de dados de vazões do sistema Hidroweb. O software desenvolvido foi denominado Sistema Computacional para Regionalização de Vazões (SisCoRV) e foi aplicado à bacia do rio Paracatu a fim de verificar as suas funcionalidades. No estudo de caso, o SisCoRV apresentou boa interatividade com a Internet, facilidade de delimitação das regiões homogêneas, eficiência na aplicação da metodologia de regionalização e capacidade para alimentação da base hidrográfica ottocodificada da ANA.

A cianobactéria Arthrospira (Spirulina) platensis, uns dos microrganismos fotossintetizantes mais estudados e cultivados no planeta, tem uma composição particular de biomassa que inclui: elevado conteúdo de proteínas, ácidos graxos poliinsaturados, pigmentos naturais e outras substâncias de interesse nas indústrias alimentícia, farmacêutica e cosmética. Estudos recentes demonstram que devido a sua composição de biomassa, está sendo estudada para a extração de biocompostos e para a produção de biocombustíveis. O uso de fontes de nitrogênio de baixo custo, como a uréia, pode contribuir para a viabilização da produção deste microrganismo. A. platensis foi cultivada em fotobiorreatores tubulares fechados de capacidade de 3,5 L, com intensidade luminosa de 120 &#181;mol fótons.m-2.s-1 utilizando processo descontinuo alimentado com uréia como fonte de nitrogênio com adição intermitente. O planejamento experimental utilizado foi de modelo fatorial 22, acrescido dos pontos centrais, mais configuração estrela que permitiu avaliar o efeito das variáveis independentes temperatura (T) e vazão molar de alimentação diária de uréia (K). Os resultados foram avaliados com auxílio da metodologia de superfície de resposta que permitiu verificar, através da otimização simultânea das variáveis independentes, uma condição ótima de T = 32 °C e K = 1,16 mM.dia-1 para o crescimento de A. platensis durante 8 dias de cultivo, conseguindo-se nestas condições, concentração celular máxima de 4186 ± 39 mg.L-1, produtividade celular de 757 ± 8 mg.L-1.d-1 e fator de conversão de nitrogênio em células de 14,3 ± 0,1 mg.mg-1. Os valores de Xm obtidos experimentalmente correspondem a 0,4 % a menos do que os valores máximos estimados pelo modelo matemático. O teor de lipídeo da biomassa não foi influenciado pelas condições experimentais adotadas neste trabalho, sendo os valores obtidos dentro da faixa citada na literatura para este microrganismo (aproximadamente 7 %). O teor de proteína da biomassa foi dependente da temperatura e da vazão molar de alimentação diária de uréia. Para vazões molares de uréia até 0.717 mM. dia-1, o aumento da temperatura diminui o teor de proteínas na biomassa. Por outro lado, para valores de vazão de uréia maiores (&#8805; 0,883 mM.dia-1), o aumento da temperatura leva ao aumento do teor de proteínas na biomassa. O maior valor de teor de proteína obtido neste trabalho foi de 39,49 % (T = 33 ºC, K = 1,879 mM.dia-1). / The cyanobacterium Arthrospira (Spirulina) platensis, ones of the most studied and cultivated photosynthetic microorganisms in the planet, has a unique biomass composition that includes: high protein content, polyunsaturated fat acids, natural pigments and other substances of interest in food, pharmaceutical and cosmetic industries. Recent studies demonstrate that due to its biomass composition, it has being studied for biocomponents extraction and bio-fuels production. The use of low cost nitrogen sources, such as urea, can contribute to the viability of this microorganism production. A. platensis was cultivated in 3.5-liters closed tubular photobioreactors, under luminous intensity of 120 &#181;mol fótons.m-2.s-1, using fed-batch cultivation process with urea as nitrogen source, added intermittently. The utilized experimental design was one of a factorial model 22, increased of the central points and star configuration, which allowed evaluating the effect of the independent variables, such as temperature (T) and urea daily molar flow-rate (K). The results were evaluated with response surface methodology (RSM) that allowed verifying, through the simultaneous optimization of the independent variables, an optimum condition of T = 32 °C and K = 1.16 mM.dia-1 for the growth of A. platensis during 8 days of culture, obtaining maximum cellular concentration of 4186 ± 39 mg.L-1, cellular productivity of 757 ± 8 mg.L-1.d-1 and nitrogen-to-cells factor of 14.3 ± 0.1 mg.mg-1. The Xm values obtained experimentally corresponds to 0.4 % less than the maximum values estimated by the mathematical model. The biomass lipid content was not influenced by the experimental conditions adopted in this work, being the obtained values within the range mentioned in the literature for this microorganism (approximately 7 %). The biomass protein content was dependent of the temperature and urea molar flow-rate. For the latter parameter, values up to 0.717 mM.dia-1, the increase in temperature diminished biomass protein content. On the other hand, for higher urea molar flow-rate values (&#8805; 0,883 mM.dia-1), the increase of temperature leads to increase of biomass protein content. The highest value of biomass protein content obtained in this work was of 39.49 % (T = 33 ºC, K = 1.879 mM.dia-1).