138 resultados para radiation detectors
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Nuclear Medicine is a medical modality of therapy and diagnostic imaging using unsealed radioactive sources for its purposes. This routine activity promotes the transit of radioactive sources for the area of installation, beyond the transit of patients injected with radioisotope, which also contribute to raising the radiometric level of environment. As a consequence, it has exposured workers and public individuals to the ionizing radiation. There are protective mechanisms of radiation exposure, personal protective equipments, and measurement planes established in standard measurement at certain points of the environment in order to identify any increase in radiometric levels and \ or contamination, but do not cover the entire space occupied by workers and patients. To accomplish with the individual dose limits established by the National Commission of Nuclear Energy, it is interesting if there is an individualized classification for each Nuclear Medicine service. This work aimed to promote an analysis of the radiometric level distribution across the extent of the Technical Nuclear Medicine Sector of Hospital of the Botucatu Medical School, and produce a spatial map to identify locations with higher exposure rate to the ionizing radiation, can be used as a risk map to assist the Occupationally Exposed Individuals (IOE). To perform the radiometric levels checking it was used a digital Geiger-Muller detector available in the sector, due to its practicality compared to other detectors. Measurements were carried out at four different times for all days of the week, at points strategically established to cover all the installation
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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This study aimed to assess measurements of temperature and relative humidity obtained with HOBO a data logger, under various conditions of exposure to solar radiation, comparing them with those obtained through the use of a temperature/relative humidity probe and a copper-constantan thermocouple psychrometer, which are considered the standards for obtaining such measurements. Data were collected over a 6-day period (from 25 March to 1 April, 2010), during which the equipment was monitored continuously and simultaneously. We employed the following combinations of equipment and conditions: a HOBO data logger in full sunlight; a HOBO data logger shielded within a white plastic cup with windows for air circulation; a HOBO data logger shielded within a gill-type shelter (multi-plate prototype plastic); a copper-constantan thermocouple psychrometer exposed to natural ventilation and protected from sunlight; and a temperature/relative humidity probe under a commercial, multi-plate radiation shield. Comparisons between the measurements obtained with the various devices were made on the basis of statistical indicators: linear regression, with coefficient of determination; index of agreement; maximum absolute error; and mean absolute error. The prototype multi-plate shelter (gill-type) used in order to protect the HOBO data logger was found to provide the best protection against the effects of solar radiation on measurements of temperature and relative humidity. The precision and accuracy of a device that measures temperature and relative humidity depend on an efficient shelter that minimizes the interference caused by solar radiation, thereby avoiding erroneous analysis of the data obtained.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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We analyze free elementary particles with a rest mass m and total energy E
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Pós-graduação em Física - IFT
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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The objective of this work was to evaluate the effects of UV-B radiation on the vegetative growth and on the gas exchange characteristics of passion fruit plants (Passiflora edulis) grown in greenhouse. The average unweighted UV-B radiation near the apex of the plants was 8 W m-2 for the UV-B treatment (high UV-B), and 0.8 W m-2 for the control plants (low UV-B). Plants were irradiated with UV-B for 7 hours per day, centered on solar noon, during 16 days. High UV-B radiation resulted in lower shoot dry matter accumulation per plant. The content of UV-B absorbing compounds and anthocyanins was increased in the plants exposed to high UV-B radiation, when compared with the control. UV-B radiation did not affect stomatal conductance or transpiration rate, but reduced photosynthesis and instantaneous water‑use efficiency, and increased intercellular CO2 concentration. The accumulation of UV-B-absorbing compounds and anthocyanins did not effectively shield plants from supplementary UV-B radiation, since the growth and photosynthetic processes were significantly reduced.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)