Uma janela tropical: an��lise do desempenho luminoso de ambientes com aberturas sombreadas para o clima de Natal/RN

This master thesis introduces assessment procedures of daylighting performance in office rooms with shaded opening, recommendations for Natal-RN (Latitude 05,47' S, Longitude 35,11' W). The studies assume the need of window exterior shading in hot and humid climate buildings. The daylighting performance analyses are based on simulated results for three levels of illuminance (300,500 e 1000 lux) between 08h00 e 16h00, in rooms with 2,80 m height, 6 m large and 4 m, 6 m e 8 m depths, with a centered single opening, window wall ratio (20%, 40% e 60%), four orientations (North, East, South and West), and two types of sky (clear and partially cloudy). The sky characteristics were statistically determined based on hourly data from INPE-CRN solar and daylighting weather station. The lighting performance is resulted from dynamic computer simulation of 72 models using Troplux 3.12. The simulation results were assessed using a new parameter to quantify the use of interior daylighting, the useful percentage of daylight (PULN), which corresponds to the time fraction with satisfactory light, in accordance with the illuminance design. The passive zone depths are defined based on the PULN. Despite the failures of illuminance data from the weather station, the analyses ratified the high potential of daylighting for shaded rooms. The most influential variables on the lighting performance are the opening size and the illuminance of design, while the orientation is a little influential

Otimiza����o de modelos de predi����o da perda de propaga����o aplic��veis em 3,5GHZ utilizando algoritmos gen��ticos

The telecommunications industry has experienced recent changes, due to increasing quest for access to digital services for data, video and multimedia, especially using the mobile phone networks. Recently in Brazil, mobile operators are upgrading their networks to third generations systems (3G) providing to users broadband services such as video conferencing, Internet, digital TV and more. These new networks that provides mobility and high data rates has allowed the development of new market concepts. Currently the market is focused on the expansion of WiMAX technology, which is gaining increasingly the market for mobile voice and data. In Brazil, the commercial interest for this technology appears to the first award of licenses in the 3.5 GHz band. In February 2003 ANATEL held the 003/2002/SPV-ANATEL bidding, where it offered blocks of frequencies in the range of 3.5 GHz. The enterprises who purchased blocks of frequency were: Embratel, Brazil Telecom (Vant), Grupo Sinos, Neovia and WKVE, each one with operations spread in some regions of Brazil. For this and other wireless communications systems are implemented effectively, many efforts have been invested in attempts to developing simulation methods for coverage prediction that is close to reality as much as possible so that they may become believers and indispensable tools to design wireless communications systems. In this work wasm developed a genetic algorithm (GA's) that is able to optimize the models for predicting propagation loss at applicable frequency range of 3.5 GHz, thus enabling an estimate of the signal closer to reality to avoid significant errors in planning and implementation a system of wireless communication

Din��mica de tempos curtos aplicado ao modelo de ising dilu��do por s��tio em duas dimens��es

Existem v��rios métodos de simulação para calcular as propriedades cr��ticas de sistemas; neste trabalho utilizamos a din��mica de tempos curtos, com o intuito de testar a efici��ncia desta t��cnica aplicando-a ao modelo de Ising com dilui����o de s��tios. A Din��mica de tempos curtos em combina����o com o m��todo de Monte Carlos verificou que mesmo longe do equil��brio termodin��mico o sistema j�� se mostra insens��vel aos detalhes microsc��picos das intera����es locais e portanto, o seu comportamento universal pode ser estudado ainda no regime de n��o-equil��brio, evitando-se o problema do alentecimento cr��tico ( critical slowing down ) a que sistema em equil��brio fica submetido quando est�� na temperatura cr��tica. O trabalho de Huse e Janssen mostrou um comportamento universal e uma lei de escala nos sistemas cr��ticos fora do equil��brio e identificou a exist��ncia de um novo expoente cr��tico din��mico θ, associado ao comportamento an��malo da magnetiza����o. Fazemos uima breve revis��o das transi����es de fase e fen��meno cr��ticos. Descrevemos o modelo de Ising, a t��cnica de Monte Carlo e por final, a din��mica de tempos curtos. Aplicamos a din��mica de tempos curtos para o modelo de Insing ferromagn��ticos em uma rede quadrada com dilui����o de s��tios. Calculamos o expoente din��micos θ e z, onde verificamos que existe quebra de classe de universilidade com rela����o ��s diferentes concentra����es de s��tios (p=0.70,0.75,0.80,0.85,0.90,0.95,1.00). calculamos tamb��m os expoentes est��ticos β e v, onde encontramos pequenas varia����es com a desordem. Finalmente, apresentamos nossas conclus��es e poss��veis extens��es deste trabalho

Ensino e orienta����o para projeto de conversores CC-CC atrav��s de aplicativos em java

Conselho Nacional de Desenvolvimento Cient��fico e Tecnol��gico (CNPq)

Teoria qu��ntica do campo escalar real com autoacoplamento qu��rtico - simula����es de Monte Carlo na rede com um algoritmo worm

Coordena����o de Aperfei��oamento de Pessoal de N��vel Superior (CAPES)

Modelagem da incerteza da distribui����o espacial de f��sforo e pot��ssio do solo sob a cultura canavieira

P��s-gradua����o em Agronomia (Ci��ncia do Solo) - FCAV

Ensaios mec��nico e aplica����o da l��gica fuzzy para avalia����o do canote do garfo

A inova����o tecnol��gica tem sido um dos fatores fundamentais que levam grandes empresas a permanecerem no topo do ranking mundial do mercado globalizado, de acordo com o avan��o tecnol��gico o setor de engenharia tem buscado solu����es que ofere��am resultados positivos em prol do crescimento de sua empresa ou organiza����o. Métodos de simulação para avalia����o do comportamento mec��nico de produtos submetidos a cargas est��ticas e cargas din��micas s��o extremamente necess��rias para redu����o dos custos de fabrica����o dos produtos. O uso de ensaios mec��nicos e virtuais �� de vital import��ncia para avalia����o do produto. O presente trabalho teve como objetivo a utiliza����o da l��gica fuzzy em um produto chamado canote do garfo da bicicleta, onde foi analisado al��m do grau de pertin��ncia variado entre 0 e 1, o grau de veracidade tamb��m variado entre 0 e 1, tendo como foco principal o comportamento do produto canote do garfo e sua valida����o.

Comportamento tribo-mec��nico e desgaste adesivo de materiais em nanoescala: an��lises por din��mica molecular e mec��nica do cont��nuo.

As formula����es baseadas na mec��nica do cont��nuo, embora precisas at�� certo ponto, por vezes n��o podem ser utilizadas, ou n��o s��o conceitualmente corretas para o entendimento de fen��menos em escalas reduzidas. Estas limita����es podem aparecer no estudo dos fen��menos tribol��gicos em escala nanom��trica, que passam a necessitar de novos métodos experimentais, te��ricos e computacionais que permitam explorar estes fen��menos com a resolu����o necess��ria. Simula����es atom��sticas s��o capazes de descrever fen��menos em pequena escala, por��m, o n��mero necess��rio de ��tomos modelados e, portanto, o custo computacional - geralmente torna-se bastante elevado. Por outro lado, os métodos de simulação associados �� mec��nica do cont��nuo s��o mais interessantes em rela����o ao custo computacional, mas n��o s��o precisos na escala at��mica. A combina����o entre essas duas abordagens pode, ent��o, permitir uma compreens��o mais realista dos fen��menos da tribologia. Neste trabalho, discutem-se os conceitos b��sicos e modelos de atrito em escala at��mica e apresentam-se estudos, por meio de simulação num��rica, para a an��lise e compreens��o dos mecanismos de atrito e desgaste no contato entre materiais. O problema �� abordado em diferentes escalas, e prop��e-se uma abordagem conjunta entre a Mec��nica do Cont��nuo e a Din��mica Molecular. Para tanto, foram executadas simula����es num��ricas, com complexidade crescente, do contato entre superf��cies, partindo-se de um primeiro modelo que simula o efeito de defeitos cristalinos no fen��meno de escorregamento puro, considerando a Din��mica Molecular. Posteriormente, inseriu-se, nos modelos da mec��nica do cont��nuo, considera����es sobre o fen��meno de ades��o. A valida����o dos resultados �� feita pela compara����o entre as duas abordagens e com a literatura.

Jogos de neg��cio : o que leva o docente de cursos da ��rea de Ci��ncias Sociais Aplicadas a adotar a ferramenta de ensino

The Business Games are a growing teaching strategy and alternative to the academic front through the new process of Teaching and Learning. Through literature review and semi-structured interviews, this work addresses the teachers considering their subjectivity in deciding JN as the three profiles suggested by Faria and Wellington (2004): those who use it, those who stopped using and those who do not. The research corpus is limited to contributions of 22 respondents between master and doctors teachers of Applied Social Sciences area courses in colleges of Bras��lia (DF), Goi��nia (GO), Ribeir��o Preto (SP) and Uberlandia (MG). The content analysis of the interviews allowed to infer that: (1) join the teaching strategy is a commitment to a complex planning, with constant training and proactivity related to student feedback; (2) abandons the practice is becoming less common, because managers tend to recommend it and there are more and more software available for specific disciplines. Its discussed also other contributions (motivations) given by respondents of the three groups that were not found in the literature. It is hoped that this work will serve (1) incentive to teachers on the use of Business Games as a teaching strategy (2) consultation by managers when they decide about purchasing simulation software. Finally, stands out that the educational success of JN depends not only on the various motivations of teachers, as well as the interest and commitment of the student.

Uma janela tropical: an��lise do desempenho luminoso de ambientes com aberturas sombreadas para o clima de Natal/RN

This master thesis introduces assessment procedures of daylighting performance in office rooms with shaded opening, recommendations for Natal-RN (Latitude 05,47' S, Longitude 35,11' W). The studies assume the need of window exterior shading in hot and humid climate buildings. The daylighting performance analyses are based on simulated results for three levels of illuminance (300,500 e 1000 lux) between 08h00 e 16h00, in rooms with 2,80 m height, 6 m large and 4 m, 6 m e 8 m depths, with a centered single opening, window wall ratio (20%, 40% e 60%), four orientations (North, East, South and West), and two types of sky (clear and partially cloudy). The sky characteristics were statistically determined based on hourly data from INPE-CRN solar and daylighting weather station. The lighting performance is resulted from dynamic computer simulation of 72 models using Troplux 3.12. The simulation results were assessed using a new parameter to quantify the use of interior daylighting, the useful percentage of daylight (PULN), which corresponds to the time fraction with satisfactory light, in accordance with the illuminance design. The passive zone depths are defined based on the PULN. Despite the failures of illuminance data from the weather station, the analyses ratified the high potential of daylighting for shaded rooms. The most influential variables on the lighting performance are the opening size and the illuminance of design, while the orientation is a little influential

Desenvolvimento de um m��todo para corre����o de curvas de desempenho em bombas centr��fugas submersas operando com fluidos viscosos

Electrical Submersible Pump (ESP) is used as an artificial lift technique. However, pumping viscous oil is generally associated with low Reynolds number flows. This condition leads to a performance degradation respect to the performance expected from the regular operation with water that most of the centrifugal pumps are originally designed for. These issues are considered in this investigation through a numerical study of the flow in two different multistage, semi-axial type ESPs. This investigation is carried out numerically using a Computational Fluid Dynamics (CFD) package, where the transient RANS equations are solved numerically. The turbulence is modeled using the SST model. Head curves for several operating conditions are compared with manufacturer���s curves and experimental data for a three-stage ESP, showing good agreement for a wide range of fluid viscosities and rotational speeds. Dimensionless numbers (���n, ���n, ���n e Re���) are used to investigate performance degradation of the ESPs. In addition, flow phenomena through the impellers of the ESPs are investigated using flow field from numerical results. Results show that performance degradation is directly related to rotational Reynolds number, Re���. In addition, it was verified that performance degradation occurs for constant normalized specific speed������n, which shows that performance degradation occurs similarly for different centrifugal pumps. Moreover, experimental data and numerical results agreed with a correlation from literature between head and flow correction factors proposed by Stepanoff (1967). A definition of modified Reynolds number was proposed and relates the head correction factor to viscosity. A correlation between head correction factor and the modified Reynolds number was proposed, which agreed well with numerical and experimental data. Then, a method to predict performance degradation based on the previous correlations was proposed. This method was compared with others from literature. In general, results and conclusions from this work can also be useful to bring more information about the flow of highly viscous fluids in pumps, especially in semi-axial, multistage ESPs.

M��ltiplas antenas como alternativa para aumentar a taxa de extra����o de chaves secretas em redes veiculares com desvanecimento lento

The communication in vehicular ad hoc networks (VANETs) is commonly divided in two scenarios, namely vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2I). Aiming at establishing secure communication against eavesdroppers, recent works have proposed the exchange of secret keys based on the variation in received signal strength (RSS). However, the performance of such scheme depends on the channel variation rate, being more appropriate for scenarios where the channel varies rapidly, as is usually the case with V2V communication. In the communication V2I, the channel commonly undergoes slow fading. In this work we propose the use of multiple antennas in order to artificially generate a fast fading channel so that the extraction of secret keys out of the RSS becomes feasible in a V2I scenario. Numerical analysis shows that the proposed model can outperform, in terms of secret bit extraction rate, a frequency hopping-based method proposed in the literature.

Medidas de concentra����o de rad��nio proveniente de argamassas de cimento portland, gesso e fosfogesso

Portland cement being very common construction material has in its composition the natural gypsum. To decrease the costs of manufacturing, the cement industry is substituting the gypsum in its composition by small quantities of phosphogypsum, which is the residue generated by the production of fertilizers and consists essentially of calcium dihydrate and some impurities, such as fluoride, metals in general, and radionuclides. Currently, tons of phosphogypsum are stored in the open air near the fertilizer industries, causing contamination of the environment. The 226 Ra present in these materials, when undergoes radioactive decay, produces the 222Rn gas. This radioactive gas, when inhaled together with its decay products deposited in the lungs, produces the exposure to radiation and can be a potential cause of lung cancer. Thus, the objective of this study was to measure the concentration levels of 222Rn from cylindrical samples of Portland cement, gypsum and phosphogypsum mortar from the state of Paran��, as well as characterizer the material and estimate the radon concentration in an environment of hypothetical dwelling with walls covered by such materials. Experimental setup of 222Rn activity measurements was based on AlphaGUARD detector (Saphymo GmbH). The qualitative and quantitative analysis was performed by gamma spectrometry and EDXRF with Au and Ag targets tubes (AMPTEK), and Mo target (ARTAX) and mechanical testing with x- ray equipment (Gilardoni) and the mechanical press (EMIC). Obtained average values of radon activity from studied materials in the air of containers were of 854 �� 23 Bq/m3, 60,0 �� 7,2 Bq/m3 e 52,9 �� 5,4 Bq/m3 for Portland cement, gypsum and phosphogypsum mortar, respectively. These results extrapolated into the volume of hypothetical dwelling of 36 m3 with the walls covered by such materials were of 3366 �� 91 Bq/m3, 237 �� 28 Bq/m3 e 208 �� 21 Bq/m3for Portland cement, gypsum and phosphogypsum mortar, respectively. Considering the limit of 300 Bq/m3 established by the ICRP, it could be concluded that the use of Portland cement plaster in dwellings is not secure and requires some specific mitigation procedure. Using the results of gamma spectrometry there were calculated the values of radium equivalent activity concentrations (Raeq) for Portland cement, gypsum and phosphogypsum mortar, which were obtained equal to 78,2 �� 0,9 Bq/kg; 58,2 �� 0,9 Bq/kg e 68,2 �� 0,9 Bq/kg, respectively. All values of radium equivalent activity concentrations for studied samples are below the maximum level of 370 Bq/kg. The qualitative and quantitative analysis of EDXRF spectra obtained with studied mortar samples allowed to evaluate quantitate and the elements that constitute the material such as Ca, S, Fe, and others.