8 resultados para DISPOSITIVOS DE CRISTALES LÍQUIDOS

em Repositório da Produção Científica e Intelectual da Unicamp


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The present work aimed the development of a low cost servo-valve that answers to an electronic control signal, for variable rates liquid inputs application. A literature research to define which valve type should be used was made. A mechanically activated proportional valve with an electronically controlled servo-engine was designed and evaluated. Since developed the servo-valve, the system was submited to a number of tests .The evaluation of its behavior was obtained in terms of repeatability, hystheresis and linearity. The test was accomplished in a bench, specially developed for this aim. As a result, were obtained three curves of opening percentage as function of flow rate, describing three opening and closing increments in two different work pressures. The servo-valve presented a good repeatability, reasonable hysteresis and a typically quadratic curve. This one maintained the low cost target. These results were very satisfied because the non-linearity and the hysteresis could be easily corrected by software.

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The efficiency of swine production performance depends on the herd administration, such as good nutrition, sanitary control, facilities and appropriate environmental conditions. The concept of this production model is directly related with the reduction of selective losses and the process control. Each production segment is controlled to reach the optimization in the system totality, it is necessary to apply animals handling concepts, environmental control implementation, diseases control, nutrition control, information concerning in guaranteeing the animal welfare and individual identification. The present work presents as objective the development of the mathematical model to evaluate interactions among the internal atmosphere of the installation and the thermal animals preference, in the expectation of detecting a relationship among the frequency access to the drinking fountain and the atmosphere conditions - temperature, black globe temperature and relative humidity, using as tool the electronic identification. The results obtained by the mathematical model, allowed to conclude accurately the evaluation of the swine thermal preference correlating with the climatic variables in the pregnancy stage.

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The application of sand filters in localized irrigation systems is recommended in the presence of organic and algae contamination. The proper design and maintenance of these equipments are essential to assure an effective water quality control, in order to reduce the emitters clogging, to keep its water application uniformity, and to prevent increasing in the system operation costs. Despite the existence of some references about design, operation and maintenance of these filters, they are dispersed, with not enough details to guarantee the optimization of its hydraulics structure design and the proper selection of porous media to be used. Therefore, the objective of this work was to report a current literature review, relating practical information with scientific knowledge. The content of this review would help to induce and intensify the research on this subject and to contribute so the operational functions for the equipment are reached. It is also expected to assist the improvement of the filtration and flushing processes in the agricultural irrigation and the development of original design procedures and the rational use of these devices.

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The copolymer poly (L-co-D,L lactic acid), PLDLA, has gained prominence in the field of temporary prostheses due to the fact that their time of degradation is quite compatible with the requirement in the case of osseous fracture. In this work the in vivo degradation of devices from copolymer, as a system of plates and screws, used in fixation of the tibia of rabbits was studied. The devices were implanted in 15 adult rabbits, albinos, New Zealand race, and they were used as control devices of alloys of titanium (Ti-6Al-4V/ V grade). The use of copolymers, synthesized in the laboratory, was tested in the repair of fracture in rabbits'tibias, being assessed in the following times: 2 weeks, 2 months and 3 months. Morphological analysis of tissue surrounding the plate and screw system, for 2 weeks of implantation, showed the presence of osteoblasts, indicating a pre bone formation. After 2 months there was new bone formation in the region in contact with the polymer. This bone growth occurred simultaneously with the process of PLDLA degradation, invading the region where there was polymer and after 3 months there was an intense degradation of the copolymer and hence greater tissue invasion compared to 2 months which characterized bone formation in a region where the polymer degraded. The in vivo degradation study of the devices for PLDLA by means of histological evaluations during the period of consolidation of the fracture showed the efficiency of plate and screw system, and it was possible to check formation of bone tissue at the implantation site, without the presence of inflammatory reaction

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PURPOSE: To compare the 2% ibopamine provocative test with the water drinking test as a provocative test for glaucoma. METHODS: Primary open-angle glaucoma patients and normal individuals were selected from CEROF-Universidade Federal de Goiânia UFG, and underwent the 2% ibopamine provocative test and the water drinking test in a randomized fashion, at least 1 week apart. Intraocular pressure (IOP) before and after both tests, Bland-Altman graph, sensitivity and specificity (as mesured by ROC curves) were obtained for both methods. RESULTS: Forty-seven eyes from 25 patients were included (27 eyes from 15 glaucoma patients and 20 eyes from 10 normal individuals), with a mean age of 54.2 ± 12.7 years. The mean MD of glaucoma patients was -2.8 ± 2.11 dB. There was no statistically difference in the baseline IOP (p=0.8) comparing glaucoma patients, but positive after the provocative tests (p=0.03), and in the IOP variation (4.4 ± 1.3 mmHg for ibopamine and 3.2 ± 2.2 mmHg for water drinking test, p=0.01). There was no difference in all studied parameters for normal individuals. The Bland-Altman graph showed high dispersion comparing both methods. The areas under the ROC curve were 0.987 for the ibopamine provocative test, and 0.807 for the water-drinking test. CONCLUSION: In this selected subgroup of glaucoma patients with early visual field defect, the ibopamine provocative test has shown better sensitivity/specificity than the water drinking test.

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Universidade Estadual de Campinas . Faculdade de Educação Física

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Universidade Estadual de Campinas . Faculdade de Educação Física

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Universidade Estadual de Campinas . Faculdade de Educação Física