abstract: Portable devices rely on battery systems that contribute largely to the overall device form factor and delay portability due to recharging. Membraneless microfluidic fuel cells are considered as the next generation of portable power sources for their compatibility with higher energy density reactants. Microfluidic fuel cells are potentially cost effective and robust because they use low Reynolds number flow to maintain fuel and oxidant separation instead of ion exchange membranes. However, membraneless fuel cells suffer from poor efficiency due to poor mass transport and Ohmic losses. Current microfluidic fuel cell designs suffer from reactant cross-diffusion and thick boundary layers at the electrode surfaces, which result in a compromise between the cell's power output and fuel utilization. This dissertation presents novel flow field architectures aimed at alleviating the mass transport limitations. The first architecture provides a reactant interface where the reactant diffusive concentration gradients are aligned with the bulk flow, mitigating reactant mixing through diffusion and thus crossover. This cell also uses porous electro-catalysts to improve electrode mass transport which results in higher extraction of reactant energy. The second architecture uses porous electrodes and an inert conductive electrolyte stream between the reactants to enhance the interfacial electrical conductivity and maintain complete reactant separation. This design is stacked hydrodynamically and electrically, analogous to membrane based systems, providing increased reactant utilization and power. These fuel cell architectures decouple the fuel cell's power output from its fuel utilization. The fuel cells are tested over a wide range of conditions including variation of the loads, reactant concentrations, background electrolytes, flow rates, and fuel cell geometries. These experiments show that increasing the fuel cell power output is accomplished by increasing reactant flow rates, electrolyte conductivity, and ionic exchange areas, and by decreasing the spacing between the electrodes. The experimental and theoretical observations presented in this dissertation will aid in the future design and commercialization of a new portable power source, which has the desired attributes of high power output per weight and volume and instant rechargeability. / Dissertation/Thesis / Ph.D. Mechanical Engineering 2010

Neste trabalho foram desenvolvidos sistemas de aquisição portáteis de formato esférico, capazes de sensoriar forças de compressão e impacto ao longo dos três eixos cartesianos. Os instrumentos desenvolvidos foram utilizados em diferentes experimentos feitos em estabelecimentos de beneficiamento de frutas (packinghouses) durante o processo de pós-colheita a fim de verificar os danos mecânicos sofridos pelas mesmas. Os instrumentos são sistemas microcontrolados compostos por quarto sensores (acelerômetros, célula de carga, temperatura e umidade), memória Flash para o armazenamento dos dados, transceptor de rádio freqüência e uma porta de comunicações serial universal (USB). A coleta, apresentação e processamentos dos dados obtidos foram feitos por um software desenvolvido em ambiente C++ para o sistema operacional Windows. Fortes forças de compressão e impacto foram registradas, sugerindo a necessidade de mudanças no processo de seleção (mecânica e manual), empacotamento e transporte de frutas. Quatro protótipos diferentes foram desenvolvidos, dois com cabos e dois sem. Os dispositivos provaram ser úteis, funcionando como esperado e o seu projeto modular permite o desenvolvimento de diferentes instrumentos. Os resultados obtidos propiciaram pesquisas relativas aos danos sofridos por frutas durante o processo de pós-colheita. / In this work, spherical shape portable data acquisition systems that are capable of sensing compression and impact forces along the three Cartesian axes were developed. The developed instruments were utilized in several different experiments done in fruit packinghouses during the post harvest process in order to check the mechanical damages they suffer. They are microcontrolled systems composed by four sensors (accelerometers, load cell, temperature and humidity), Flash memory for data storage, radio frequency transceiver and a universal serial bus (USB) communication port. The download, presentation and data processing were done by developed C++ software that runs in a Windows environment. Strong compression and impact forces were recorded, suggesting a need for changes in the mechanical and manual selection, packing and transportation of fruits. Four different prototypes were developed, two corded and two wireless versions. The devices developed were proven to be useful, worked as expected and their modular design permit future developments. The results allowed for different research concerning the damages suffered by the fruits, during the post harvest process.

Even today, there may be differences between the various facilities of fire protection in the field of portable pumps. Some units have a new and technically compliant mobile pumps, others have older portable pumps or even none. My primary interest was the current state of condition and technical level of the individual pumps. The Pumps and the issue of fire protection are mentioned in the first part. There is described a legal framework defining competencies, division, as well as the working of each fire protection units. Information on the various types of water pumps used not only in fire protection, working principles and specifics of mobile water pumps are also described here in a retrieval of information resources. The second part, which is my own research, is analysis of condition of mobile water pumps on selected sample of fire protection units from the region of Liberec. This practical task was realized by my myself questionnaires that I sent out to chosen fire protection units. Additional information was acquired thanks to personal interviews with representatives of the units. My field of interest was the quality of condition of mobile water pumps. The finally condition depends on the fact if the fire units own the pumps and their technical level. The monitored parameters were old pumps, maximum power, maximum discharge height, weight and maximum flow rate of the pump. The quality of the conditions of mobile water pumps of fire protection units was evaluated by using my own modification of operational analysis. The index of condition as a unique identifier was the outcome of the evaluation. The hypothesis The condition of mobile water pumps of chosen fire protection units corresponds today's technical possibilities - had prescientific character and it was formulated intuitively. The hypothesis also contained expectations of high and technically adequate condition of mobile water pumps of chosen fire protection units. Basis for the hypothesis flowed from the experience of recent years, when the fire brigade were gradually upgraded its founders. Based on the results it is possible to confirm the hypothesis and indicate the condition of chosen fire protection units from the region of Liberec as a sufficient because all of them pass the basic limit. To achieve four specific aims of this work the comparison of monitored technical parameters and the number of pumps with limit for condition was used. These aims of the thesis were complete thanks to these methods except one. It was the plan of modernization at the fire protection unit, which does not correspond amenities. Since the confirmation of the hypothesis, which states that mobile pumps amenities for today's technical possibilities, no need to drive to modernize the newer models. You are at least mentioned in the results of the work, and their technical parameters are included in the annex. If we take into account the practical point of view, this work is useful for the Fire Brigade Liberec region, such as document monitoring conditions of mobile water pumps of chosen fire protection unit from Liberec region.

The aim of my diploma thesis was to assess possibilities of tracing and, consequently, identifying radionuclides in transported materials detected by detection frames on the protected area border of the nuclear power plant of Temelín, by means of the portable spectrometer Inspector 1000. To achieve this, I designed a series of measurements based on a simulated passage of a motor vehicle fitted with ionizining radiation sources of various activities at the designed points of measurement so that these measurements corresponded as close as possible to the actual passage of vehicles with large-sized loads. Recorded values were analysed and marginal activities for the particular measuring points were fixed. Computation correctness was then verified by another passage of the vehicle through the measuring device. Specified values of the marginal activities at the particular measuring points were, for comparison, consequently measured by the portable spectrometer Inspector 1000. Measurement results proved that the portable spectrometer Inspector 1000 can efficiently detect, identify and locate the sources of ionizing radiation causing the alarm level to be exceeded on a stable measuring device at the fixed measuring points, with a higher sensitivity than a stable measuring device. Conclusions of this diploma thesis will be given to the radiation protection unit of the nuclear power plant of Temelín as a basis for specification or even expansion of the methods of measuring ionizining radiation sources when transporting large-sized loads in the nuclear power plant, and their introduction into the monitoring programme.

Made available in DSpace on 2014-06-11T19:31:35Z (GMT). No. of bitstreams: 0 Previous issue date: 2006-04-28Bitstream added on 2014-06-13T20:02:25Z : No. of bitstreams: 1 colenci_ra_dr_botfca.pdf: 998064 bytes, checksum: 8c2f921462491c32d9ae3f78277e6aed (MD5) / Universidade Estadual Paulista (UNESP) / A propriedade mecânica denominada dureza é largamente utilizada na especificação de materiais, nos estudos e pesquisas mecânicas e metalúrgicas e no controle de qualidade de diversos materiais. No caso particular da madeira, dentre as diversas propriedades mecânicas empregadas como ferramentas para avaliação da sua qualidade e de seu potencial tecnológico, tem destaque a dureza Janka, que avalia a relação entre uma força de penetração superficial de uma pequena esfera de aço na madeira e a endentação promovida por essa esfera. Constitui-se em ensaios simples, rápido, e com boas correlações com a resistência à compressão paralela às fibras da madeira, referência maior na classificação estrutural deste material. Mais recentemente, trabalhos internacionais reportaram o uso da dureza Brinell para avaliação de madeiras. Além das vantagens já reportadas para a dureza Janka, a dureza Brinell traria a facilidade de realização dos ensaios em condições de campo, sobretudo pela menor magnitude dos esforços envolvidos na cravação do endentador na superfície do material. Dando continuidade a estudos já desenvolvidos, este trabalho teve como objetivo estudar critérios ou práticas, aplicáveis no campo e em exemplares individuais, para a qualificação mecânica de algumas espécies de madeira com a finalidade de classificação, e aprovação ou reprovação de lotes de dormentes de madeira para uso ferroviário. Os estudos iniciais conduziram ao projeto e desenvolvimento de equipamento 2 para avaliação em campo da dureza de madeiras - Durômetro portátil para madeiras embasado, no geral, na metodologia Brinell com mensuração dos diâmetros da calota endentada no material sob análise. Os ensaios de teste funcional e de calibração do equipamento foram conduzidos utilizando-se 16 lotes de madeiras de reflorestamentos e nativas... / The mechanical property called hardness is largely used in material specifications, in mechanical and metallurgical studies and research and in the quality control of several kinds of materials. Specifically for timber, among the several mechanical properties used as tools for its quality control and technological potential, Janka hardness, which evaluate the relation between a superficial penetration force of a small steel sphere in wood and the indentation produced by such sphere, are highlighted. It is constituted by simple, quick and easily performed test, with good correlations with the compression parallel to grain strength, a high reference in structural classification for this material. More recently, international studies have reported the use of Brinell hardness for timber assessment. Besides the advantages previously mentioned for Janka hardness, the Brinell one would make it easier to perform the tests in field conditions, especially for its lower magnitude in terms of the involved loads. Continuing studies already developed with such property for timber, this work had the objective of studying criteria or practices applicable on field and in individual wood elements, for the mechanical qualification of some timber species towards its classification, and approval or failing of timber sleeper lots for rail usage. The initial studies led to the project and development of an equipment for timber hardness field evaluation - portable Hardometer for timber. 4 The functional and calibration test of the equipment were carried out using 16 native and exotic timber lots, among there E.citriodora, E. tereticornis, E. saligna, E. urophylla, E. grandis, Goupia glabra (Cupiúba) and Bagassa guianenses (Tatajuba), with variation of origins beyond species. Each lot had 12 specimens. The calibration tests, performed with timber on its moisture above the FSP (fiber saturation point)... (Complete abstract click electronic access below)

Neste trabalho foram desenvolvidos sistemas de aquisição portáteis de formato esférico, capazes de sensoriar forças de compressão e impacto ao longo dos três eixos cartesianos. Os instrumentos desenvolvidos foram utilizados em diferentes experimentos feitos em estabelecimentos de beneficiamento de frutas (packinghouses) durante o processo de pós-colheita a fim de verificar os danos mecânicos sofridos pelas mesmas. Os instrumentos são sistemas microcontrolados compostos por quarto sensores (acelerômetros, célula de carga, temperatura e umidade), memória Flash para o armazenamento dos dados, transceptor de rádio freqüência e uma porta de comunicações serial universal (USB). A coleta, apresentação e processamentos dos dados obtidos foram feitos por um software desenvolvido em ambiente C++ para o sistema operacional Windows. Fortes forças de compressão e impacto foram registradas, sugerindo a necessidade de mudanças no processo de seleção (mecânica e manual), empacotamento e transporte de frutas. Quatro protótipos diferentes foram desenvolvidos, dois com cabos e dois sem. Os dispositivos provaram ser úteis, funcionando como esperado e o seu projeto modular permite o desenvolvimento de diferentes instrumentos. Os resultados obtidos propiciaram pesquisas relativas aos danos sofridos por frutas durante o processo de pós-colheita. / In this work, spherical shape portable data acquisition systems that are capable of sensing compression and impact forces along the three Cartesian axes were developed. The developed instruments were utilized in several different experiments done in fruit packinghouses during the post harvest process in order to check the mechanical damages they suffer. They are microcontrolled systems composed by four sensors (accelerometers, load cell, temperature and humidity), Flash memory for data storage, radio frequency transceiver and a universal serial bus (USB) communication port. The download, presentation and data processing were done by developed C++ software that runs in a Windows environment. Strong compression and impact forces were recorded, suggesting a need for changes in the mechanical and manual selection, packing and transportation of fruits. Four different prototypes were developed, two corded and two wireless versions. The devices developed were proven to be useful, worked as expected and their modular design permit future developments. The results allowed for different research concerning the damages suffered by the fruits, during the post harvest process.

Doctor of Philosophy / Department of Mechanical and Nuclear Engineering / B. Terry Beck / The current experimental method to determine the transfer length in prestressed concrete members consists of measuring concrete surface strains before and after de-tensioning with a mechanical strain gage. The method is prone to significant human errors and inaccuracies. In addition, since it is a time-consuming and tedious process, transfer lengths are seldom if ever measured on a production basis. A rapid, non-contact method for determining transfer lengths in prestressed concrete members has been developed. The new method utilizes laser-speckle patterns that are generated and digitally recorded at various points along the prestressed concrete member. User-friendly software incorporating robust and fast digital image processing algorithms was developed by the author to extract the surface strain information from the captured speckle patterns. Based on the laser speckle measurement technique, four (4) successively improved generations of designs have been made. A prototype was fabricated for each design either on an optical breadboard for concept validation, or in a portable self-contained unit for field testing. For each design, improvements were made based on the knowledge learned through the testing of the previous version prototype. The most recent generation prototype, incorporating a unique modular design concept and self-calibration function, has several preferable features. These include flexible adjustment of the gauge length, easy expansion to two-axis strain measurement, robustness and higher accuracy. Extensive testing has been conducted in the laboratory environment for validation of the sensor’s capability in concrete surface strain measurement. The experimental results from the laboratory testing have shown that the measurement precision of this new laser speckle strain measurement technique can easily achieve 20 microstrain. Comparison of the new sensor measurement results with those obtained using traditional strain gauges (Whittemore gauge and the electrical resistance strain gauge) showed excellent agreement. Furthermore, the laser speckle strain sensor was applied to transfer length measurement of typical prestressed concrete beams for both short term and long term monitoring. The measurement of transfer length by the sensor was unprecedented since it appears that it was the first time that laser speckle technique was applied to prestressed concrete inspection, and particularly for use in transfer length measurement. In the subsequent field application of the laser speckle strain sensor in a CXT railroad cross-tie plant, the technique reached 50 microstrain resolution, comparable to what could be obtained using mechanical gauge technology. It was also demonstrated that the technique was able to withstand extremely harsh manufacturing environments, making possible transfer length measurement on a production basis for the first time.

Made available in DSpace on 2014-10-09T12:52:22Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:00:47Z (GMT). No. of bitstreams: 0 / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

Made available in DSpace on 2014-10-09T12:51:54Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:08:15Z (GMT). No. of bitstreams: 0 / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Tese (Doutoramento) / IPEN/T / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP / FAPESP:04/06915-1

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No. of bitstreams: 1 oliveirajunior_ajo_me_bot.pdf: 5639185 bytes, checksum: 41dab40b84e40ca63b845dee1590104f (MD5) Previous issue date: 2016-07-27 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Nos países de clima tropical, como o Brasil, um dos maiores desafios para produção animal e trabalho humano são os fatores ambientais, como altas temperaturas e umidades dentro de ambientes, assim como as tipologias das instalações, muitas vezes limitantes para o desempenho produtivo. O conforto térmico e a ambiência são áreas de estudo que tem por objetivo conceder o bem-estar para indivíduos, sejam eles animais ou seres humanos. Nos dias atuais grande parte das análises de conforto térmico no meio agrícola, ressaltando às em ambientes de produção animal, utilizam índices que possibilitam a avaliação do nível de estresse térmico de um determinado local por meio de variáveis climatológicas, como o Índice de Temperatura e Umidade – ITU, Índice de Temperatura de Globo Negro e Umidade – ITGU e Índice de Temperatura Equivalente – ITEq. Semelhantemente, em locais de trabalho humano há um limite de tolerância para exposição ao calor que deve ser monitorado mediante o chamado Índice de Bulbo Úmido Termômetro de Globo – IBUTG. Para a resolução desses índices, não há atualmente um sistema computacional específico, de hardware e software, que forneça, em tempo real, a condição térmica de um ambiente. Deste modo, o presente trabalho teve por objetivo desenvolver um sistema computacional capaz de avaliar, em tempo real, o conforto térmico de instalações de produção animal e de ambientes de trabalho humano. O sistema foi desenvolvido baseado na criação de um dispositivo portátil para coleta e transmissão das variáveis climatológicas de temperatura do ar, temperatura de globo negro e umidade relativa do ar, e do desenvolvimento de um aplicativo para smartphones e tablets Android. O dispositivo portátil foi desenvolvido utilizando um microcontrolador padrão Arduino, juntamente com sensores de temperatura e umidade relativa do ar. Para o desenvolvimento do aplicativo para dispositivos móveis, foi utilizado a linguagem de programação orientada a objetos Java no ambiente de desenvolvimento integrado Android Studio. O aplicativo para dispositivos móveis e o dispositivo portátil foram aplicados em diferentes ambientes e apresentaram correta medição de variáveis climatológicas e cálculo dos índices de conforto térmico. O dispositivo portátil demonstrou ser um produto funcional na transmissão de dados para dispositivos móveis. / In tropical weather countries, such as Brazil, one of the greatest challenges for animal production and human work environments are environmental factors, among them high temperature and humidity inside of the environments, as well as the type of facilities which are limiting for productive performance. The thermal comfort and the ambience are study areas that aims the well-being of individuals, whether they are animals or humans. It is possible to define thermal comfort as the pleasant thermal sensation of the body, in which are not necessary physiological efforts to keep the body in thermal balance. Nowadays, several analysis of thermal comfort in the agriculture environment, mainly at environments of animal production, apply indexes to make it possible the evaluation of thermal stress level of a specific place through the climatological variables, for instance, the Temperature and Humidity Index – THI, Black Globe-Humidity Index – BGHI and Heat Load Index – HLI. In the same way, at places of human work, there is a tolerance limit for heat exposition that should be monitored by the known Wet-bulb Globe Temperature Index – WBGT index. Currently, for resolution of these indexes, there is not a specific computational system (hardware and software) that provides the thermal comfort of an environment in real time. Therefore, the present work aimed to develop a computational system with features to evaluate in real time the thermal comfort of facilities of animal production and human work. The system was developed based on the creation of a mobile device to collect and transmit weather variables from the air temperature, black globe temperature and relative air humidity, and also the development of an app for smartphones and tablets. The mobile device was developed using the Arduino microcontroller, along with sensors of air temperature and relative humidity. For the development of the app it was used the Java oriented object program language, with the Android integrated development environment. The app for mobile devices and the portable device were applied in different environments and both presented a correctly measurement of climatological variables and the calculating of thermal comfort indexes. The portable device proved to be a functional product in data transmission for mobile devices.