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Registros recuperados: 22
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A clinical gamma camera-based pinhole collimated system for high resolution small animal SPECT imaging BJMBR
Mejia,J.; Galvis-Alonso,O.Y.; Castro,A.A.de; Braga,J.; Leite,J.P.; Simões,M.V..
The main objective of the present study was to upgrade a clinical gamma camera to obtain high resolution tomographic images of small animal organs. The system is based on a clinical gamma camera to which we have adapted a special-purpose pinhole collimator and a device for positioning and rotating the target based on a computer-controlled step motor. We developed a software tool to reconstruct the target’s three-dimensional distribution of emission from a set of planar projections, based on the maximum likelihood algorithm. We present details on the hardware and software implementation. We imaged phantoms and heart and kidneys of rats. When using pinhole collimators, the spatial resolution and sensitivity of the imaging system depend on parameters such as...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Pinhole collimator; SPECT; Small animal organs; Maximum likelihood; Instrumentation; Image processing.
Ano: 2010 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2010001200004
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A Correction for the Thermal Mass-Induced Errors of CTD Tags Mounted on Marine Mammals ArchiMer
Mensah, Vigan; Roquet, Fabien; Siegelman-charbit, Lia; Picard, Baptiste; Pauthenet, Etienne; Guinet, Christophe.
The effect of thermal mass on the salinity estimate from conductivity-temperature-depth (CTD) tags sensor mounted on marine mammals is documented, and a correction scheme is proposed to mitigate its impact. The algorithm developed here allows for a direct correction of the salinity data, rather than a correction of the sample's conductivity and temperature. The amplitude of the thermal mass-induced error on salinity and its correction are evaluated via comparison between data from CTD tags and from Sea-Bird Scientific CTD used as a reference. Thermal mass error on salinity appears to be generally O(10(-2)) g kg(-1), it may reach O(10(-1)) g kg(-1), and it tends to increase together with the magnitude of the cumulated temperature gradient (T-HP) within the...
Tipo: Text Palavras-chave: Data processing; In situ oceanic observations; Instrumentation; Sensors; Profilers; Oceanic.
Ano: 2018 URL: https://archimer.ifremer.fr/doc/00585/69697/67577.pdf
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A MEASUREMENT SYSTEM BASED ON LiDAR TECHNOLOGY TO CHARACTERIZE THE CANOPY OF SUGARCANE PLANTS REA
Canata,Tatiana F.; Molin,José P.; Sousa,Rafael V. de.
ABSTRACT Laser sensor applications associated with LiDAR (Light Detection and Ranging) technology on platforms allow the evaluation of crop and forest biomass in a non-invasive way. This study presents the development of a measurement system based on LiDAR technology aimed at the proposed assessment of the height of sugarcane plants during the pre-harvest period. A laser sensor, a GNSS (Global Navigation Satellite System) receiver, and an inertial unit compose the measurement system. The equipment was integrated with a computer for data acquisition and installed on an agricultural tractor platform. The GNSS receiver with a real-time kinematic signal was synchronized to the laser sensor to obtain the point cloud and to the inertial unit to evaluate the...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Canopy geometry; Instrumentation; Laser sensor; Remote sensing.
Ano: 2019 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162019000200240
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Argos-3 Satellite Communication System: Implementation on the Arvor Oceanographic Profiling Floats ArchiMer
Andre, Xavier; Moreau, Bertrand; Le Reste, Serge.
The scientific community observes the ocean for applications in the fields of oceanography and climate research. In order to recover in situ data, more than 3,000 profiling floats are operated in the framework of the Argo Program. Each float performs cycles between the sea surface and a depth of 2,000 meters. Scientific data are gathered while the float is travelling upward from the depths of the oceans, and are then transmitted via a satellite communication system at the end of each cycle. During its time at the surface, mainly dedicated to transmissions, the float is vulnerable and subject to drift, which limits its use in many studies. Moreover, transmission times are becoming longer due to a trend towards high resolution or multi-sensor profiles....
Tipo: Text Palavras-chave: Buoy observations; In situ oceanic observations; Instrumentation; Sensors; Profilers; Oceanic.
Ano: 2015 URL: http://archimer.ifremer.fr/doc/00284/39519/38011.pdf
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Calibration and study of soil physical-hydric relations using a frequency domain reflectometry probe CIGR Journal
Duarte, Thiago; Silva, Tonny José Araújo da; Bonfim-Silva, Edna Maria; Souza, Hanna Pricilla Barbosa.
The FDR Diviner 2000® probe is widely used to monitor soil moisture and to study physical-hidric relationships. The calibration equation provided by the manufacturer may not correctly reproduce the actual moisture value for the same type of soil with different bulk densities. In addition, it was postulated in this experiment that the capacitance probe can be used to determine the soil water tension and the initial soil water retention curve. Thus, the objectives were: to assess whether the calibration equation parameters of the FDR probe changes with the bulk density variation; estimate the soil water tension using the FDR probe; and verify the effect of the probe calibration in determining the initial soil water retention curve for the Red Oxisol at three...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Soil physics; Soil moisture; Soil compaction; Instrumentation; Diviner 2000®..
Ano: 2021 URL: http://www.cigrjournal.org/index.php/Ejounral/article/view/6673
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Control system for forced-air cooling of horticultural products REA
Silva,João C. T. R. da; Mederos,Bárbara J. T..
This work is a study of the implementation of a classical controller using a tuning method referred to as IMC (Internal Model Control) and aimed at the reduction of electrical energy consumption by the appropriate relation between energy consumption and the cooling time with forced air. The supervisory system installed was able to manipulate the variable of frequency of the signal power of the exhaust fan engine (forced air module), to accelerate or decelerate the loss of heat from the product to be cooled by airflow variation that passes through the mass of the produce. The results demonstrated a reduction in energy consumption from 64% and an increase of only 8% in the cooling time to the system using PI/IMC (Proportional - Integral with IMC) tuning...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Instrumentation; Controller tuning; IMC method; Cooling time; Supervisory system.
Ano: 2011 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162011000400001
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Datalogging instrument arrays: powerful yet inexpensive tools for recording the heterogeneous physical environment of coral reefs ArchiMer
Moore, Sw.
The physical structure of coral reefs, like that of rainforests and other spatially-complex ecosystems, modulates light, fluid flow, and other physical variables to create a spatially and temporally complex mosaic of microhabitats. Accurate and affordable methods for quantifying this spatio-temporal variation are required to address many basic and applied research questions related to the ecology and management of reefs. Recent advances in semiconductor electronics technology have made it easier and much less expensive to build small and reliable datalogging instruments, which can be deployed in arrays to record spatio-temporal patterns of ecologically-important variables. Suitable instruments are already commercially available for $100 (US) or less per...
Tipo: Text Palavras-chave: Instrumentation; Habitat; Écologie physique; Électronique; Instrumentation; Habitat characterization; Physical ecology; Electronics.
Ano: 1999 URL: http://archimer.ifremer.fr/doc/00325/43592/44033.pdf
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Desenvolvimento e calibração de uma guia de onda para TDR. Repositório Alice
ANDRADE, C. L. T.; OR, D.; COSTA, E. L.; COUTO, L.; ALBUQUERQUE, P. E. P..
A medicao da umidade do solo e crucial para pesquisa e manejo de irrigacao. Entre os metodos mais recentes de determinacao de umidade esta o da TDR ("time domain reflectometry") que se baseia na correlacao entre a propriedade dieletrica do solo e a sua umidade. A obtencao do perfil de umidade do solo requer a utilizaco de um grande numero de guias de onda, cujo custo ainda e elevado. Por outro lado, as curvas de calibracao relacionando umidade com constante dieletrica do solo foram desenvolvidas para solos de paises temperados. Os objetivos desse trabalho foram construir uma guia de onda com materiais facilmente encontrados no mercado nacional e calibra-la para solos tropicais. As curvas de calibracao para areia quartzosa e latossolo vermelho escuro sao...
Tipo: Parte de livro Palavras-chave: Instrumentacao.; Irrigação; Umidade; Solo.; Instrumentation; Irrigation; Soil; Water content..
Ano: 2001 URL: http://www.alice.cnptia.embrapa.br/alice/handle/doc/485175
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Development of a shelling method to recover whole kernels of the Cutia nut (Couepia edulis) Rev. Bras. Frutic.
Pessoa,José Dalton Cruz; Leeuwen,Johannes Van.
The kernel of the cutia nut (castanha-de-cutia, Couepia edulis (Prance) Prance) of the western Amazon, which is consumed by the local population, has traditionally been extracted from the nut with a machete, a dangerous procedure that only produces kernels cut in half. A shelling off machine prototype, which produces whole kernels without serious risks to its operator, is described and tested. The machine makes a circular cut in the central part of the fruit shell, perpendicular to its main axis. Three ways of conditioning the fruits before cutting were compared: (1) control; (2) oven drying immediately prior to cutting; (3) oven drying, followed by a 24-hour interval before cutting. The time needed to extract and separate the kernel from the endocarp and...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Instrumentation; Nut; Kernel; Shelling; Extraction method; Amazon.
Ano: 2006 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-29452006000200018
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DYNAMIC TRACTION OF A MECHANIZED SET BASED ON TECHNICAL AND OPERATIONAL PARAMETERS REA
Leite,Daniel M.; Fernandes,Haroldo C.; Teixeira,Mauri M.; Cecon,Paulo R.; Furtado Júnior,Marconi R..
ABSTRACT The objective of this study was to evaluate and model the traction performance parameters of a tractor 4x2 FWD, according to the tractor speed, the internal pressure and the type of tires construction. For each type of tire construction was assembled an experiment in which we evaluated the influence of internal pressures of the front and rear tires and the speed of the mechanical assembly. It was found that the sliding of the diagonal run, presented significant effect in all variables analyzed, since the radial showed no influence of the factors evaluated. The power available in the drawbar was higher when the tractor was equipped for radial tires. The response variables, fuel consumption schedule and specific fuel consumption were more sensitive...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Harrow disc; Instrumentation; Traction performance.
Ano: 2017 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162017000300484
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Evaluation of temperatures in a refrigerated container for chilled and frozen food transport Ciênc. Tecnol. Aliment.
Pereira,Vítor de Freitas; Doria,Eduardo Castello Branco; Carvalho Júnior,Bento da Costa; Neves Filho,Lincoln de Camargo; Silveira Júnior,Vivaldo.
The objective of this work was to monitor the operational conditions of the transport of chilled and frozen foods during delivery within cities and to evaluate the impact of the door openings on the alteration of the internal temperature of the refrigerated environment. Several temperature and pressure sensors were used in a refrigerated container with two compartments and they were installed in the refrigeration system unit and on the internal and external surfaces of the container. After the monitoring tests, it was verified that door openings during deliveries resulted in a disturbance that raised the internal temperature of the refrigerated container above values recommended for adequate conservation of the products transported. Moreover, increasing...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Chilled; Container; Food; Frozen; Instrumentation; Transport.
Ano: 2010 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0101-20612010000100024
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Fluxo de seiva pelo método do balanço de calor: base teórica, qualidade das medidas e aspectos práticos. Repositório Alice
MARIN, F. R.; RIBEIRO, R. V.; ANGELOCCI, L. R.; RIGHI, E. Z..
O método do balanço de calor representa uma técnica importante para estudos sobre fisiologia vegetal, agrometeorologia e irrigação. Sua aplicação tem aumentado nos últimos anos em decorrência da maior facilidade de importação de material e equipamentos e do uso mais disseminado dos sistemas automáticos de aquisição de dados. Avanços importantes em diversas áreas de pesquisa têm sido alcançados com a possibilidade de se quantificar o consumo hídrico em plantas isoladas em diferentes escalas de tempo. Com base na teoria do método, esta revisão tem como objetivo apresentar e discutir os procedimentos de instalação, manutenção e de análise e processamento dos dados com vistas ao uso mais adequado da técnica e à obtenção de dados mais confiáveis e coerentes....
Tipo: Artigo de periódico Palavras-chave: Consumo hídrico; Instrumentação; Transpiração; Water consumption; Processamento de dados.; Instrumentation.
Ano: 2008 URL: http://www.alice.cnptia.embrapa.br/alice/handle/doc/1375
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HYSTERESIS AND THERMAL INERTIA OF SPHERES OF ALTERNATIVE MATERIALS FOR BLACK GLOBE THERMOMETERS REA
Sampaio,Carlos A. de P.; Terezo,Rodrigo F.; Vassem Júnior,Ilson; Silva,Leonardo M. da C.; Borges,Luiza K..
ABSTRACT This research was conducted with the objective of evaluating the thermal inertia and hysteresis of the following materials in a wind tunnel: hollow copper sphere with 150.0 mm diameter used as standard in globe thermometers, hollow brass sphere with 75.0 mm diameter, and two hollow plastic spheres with 115.5 and 69.7 mm diameter. The results showed that the thermal inertia and hysteresis for the hollow copper sphere were approximately 24 and 28 min, respectively; these values were bigger than those obtained for the other spheres, implying faster responses of these. While there were no statistical differences in the measurements conducted by globe thermometers which are used to indicate the black globe temperature with the different types of...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Thermal comfort; Instrumentation; Thermal properties; Radiant temperature.
Ano: 2019 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162019000500567
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Low cost driver device for microclimate maintenance in the pre-milking of dairy cattle REA
Silva,Irenilson M. da; Pandorfi,Héliton; Vasconcelos,Ângelo J. S. de; Laurenti,Renato; Guiselini,Cristiane.
Due to the importance of the environment on animal production and thus environmental control, the study aims to build a system for monitoring and control the meteorological variables, temperature and relative humidity, low cost, which can be associated with an evaporative cooling system (ECS). The system development included all the stages of assembly, test and laboratory calibration, and later the validation of the equipment carried in the field. The validation step showed results which allowed concluding that the system can be safely used in the monitoring of these variables. The controller was efficient in management of the microclimate in the waiting corral and allowed the maintenance of the air temperature within the comfort range for dairy cattle in...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Dairy cattle; Thermal comfort; Instrumentation.
Ano: 2013 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162013000100001
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Metrological assessment of TDR performance for measurement of potassium concentration in soil solution AGRIAMBI
Ponciano,Isaac de M.; Miranda,Jarbas H. de; Cooke,Richard A.; Grah,Vanessa de F.; Silva,Alisson J. P. da.
ABSTRACT Despite the growing use of the time domain reflectometry (TDR) technique to monitoring ions in the soil solution, there are few studies that provide insight into measurement error. To overcome this lack of information, a methodology, based on the central limit theorem error, was used to quantify the uncertainty associated with using the technique to estimate potassium ion concentration in two soil types. Mathematical models based on electrical conductivity and soil moisture derived from TDR readings were used to estimate potassium concentration, and the results were compared to potassium concentration determined by flame spectrophotometry. It was possible to correct for random and systematic errors associated with TDR readings, significantly...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Central limit theorem; Instrumentation; Electrical conductivity.
Ano: 2016 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-43662016000400343
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Proposal of methodology and test protocol for evaluating and qualifying pH measuring devices BABT
Almeida,Niza Helena de; Nohama,Percy.
We present a proposal for evaluating and qualifying pH measuring devices based on the requirements of relevant standards. The proposal presented is based on ASTM E70, NBR 7353, JIS Z 8805, BS 3145, DIN 19268, NBR ISO 17025 and other standards, as well as the results of field research carried out in conjunction with professionals performing pH measurements in public health laboratories. Evaluation is performed by inspection of a form which records data from the measuring system. The form gives acceptable variations in the parameters being tested and allows a conclusion to be reached regarding acceptability of the system. Using the proposed protocol allows definition of suitable analysis criteria, while taking into account the influence pH measurement is...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Quality control; PH measurement; Instrumentation.
Ano: 2006 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132006000200005
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Quantification of the least limiting water range in an oxisol using two methodological strategies Rev. Bras. Ciênc. Solo
Moreira,Wagner Henrique; Tormena,Cássio Antônio; Betioli Junior,Edner; Figueiredo,Getulio Coutinho; Silva,Álvaro Pires da; Giarola,Neyde Fabíola Balarezo.
The least limiting water range (LLWR) has been used as an indicator of soil physical quality as it represents, in a single parameter, the soil physical properties directly linked to plant growth, with the exception of temperature. The usual procedure for obtaining the LLWR involves determination of the water retention curve (WRC) and the soil resistance to penetration curve (SRC) in soil samples with undisturbed structure in the laboratory. Determination of the WRC and SRC using field measurements (in situ ) is preferable, but requires appropriate instrumentation. The objective of this study was to determine the LLWR from the data collected for determination of WRC and SRC in situ using portable electronic instruments, and to compare those determinations...
Tipo: Info:eu-repo/semantics/other Palavras-chave: Water content; Instrumentation; Critical bulk density; Soil physical quality; Matric potential.
Ano: 2014 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832014000600012
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Radiation balance of coffee hedgerows. Repositório Alice
ANGELOCCI, L. R.; MARIN, F. R.; PILAU, F. G.; RIGHI, E. Z.; FAVARIN, J. L..
A radiação, tanto de ondas curtas como de ondas longas, absorvida por um renque de plantas de uma cultura que cobre de forma descontínua o solo, é uma variável importante para os estudos das trocas de massa e de energia com a atmosfera. Este trabalho apresenta um dispositivo que movimenta oito saldo-radiômetros dispostos em torno de um renque. O movimento de ida e volta ao longo de um trecho de um renque, permite a integração do saldo de radiação na superfície de um cilindro nocional de medidas, representando o balanço de radiação (Rnc) do trecho mostrado. O equipamento apresentou um bom desempenho quando empregado em dois cafezais, mostrando potencial para a realização de medidas de campo, com valores medidos confiáveis. Foram obtidos boas correlações...
Tipo: Artigo de periódico Palavras-chave: Correlação; Instrumentação; Modelagem; Café; Radiação solar; Solar radiation; Instrumentation; Correlation.
Ano: 2008 URL: http://www.alice.cnptia.embrapa.br/alice/handle/doc/9599
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Radiation balance of coffee hedgerows AGRIAMBI
Angelocci,Luiz R.; Marin,Fábio R.; Pilau,Felipe G.; Righi,Evandro Z.; Favarin,José L..
The radiation balance of hedgerows is an important variable in studies of mass and energy exchanges between parcial ground cover crops and the atmosphere. This paper describes a device with eight net radiometers encompassing the plants of a hedgerow. The radiometers were moved along a length of hedgerow, in a continuous and reversible movement. The canopy net radiation in this length (Rnc) was found by integration of the measurements over the notional cylinder formed. The device showed good performance and provided reliable measurements of Rnc of coffee hedgerows, showing itselfto be an useful technique of measurement in field conditions. Good correlations between Rnc and global solar radiation, turfgrass and coffee crop net radiation were found in 15-min,...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Correlation; Instrumentation; Solar radiation; Net radiation.
Ano: 2008 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-43662008000300008
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Southern Ocean frontal structure and sea-ice formation rates revealed by elephant seals ArchiMer
Charrassin, J. -b.; Hindell, M.; Rintoul, S. R.; Roquet, Fabien; Sokolov, S.; Biuw, M.; Costa, D.; Boehme, L.; Lovell, P.; Coleman, R.; Timmermann, R.; Meijers, A.; Meredith, M.; Park, Y. -h.; Bailleul, F.; Goebel, M.; Tremblay, Y; Bost, C. -a.; Mcmahon, C. R.; Field, I. C.; Fedak, M. A.; Guinet, C.
Polar regions are particularly sensitive to climate change, with the potential for significant feedbacks between ocean circulation, sea ice, and the ocean carbon cycle. However, the difficulty in obtaining in situ data means that our ability to detect and interpret change is very limited, especially in the Southern Ocean, where the ocean beneath the sea ice remains almost entirely unobserved and the rate of sea-ice formation is poorly known. Here, we show that southern elephant seals (Mirounga leonina) equipped with oceanographic sensors can measure ocean structure and water mass changes in regions and seasons rarely observed with traditional oceanographic platforms. In particular, seals provided a 30-fold increase in hydrographic profiles from the sea-ice...
Tipo: Text Palavras-chave: Antarctic circumpolar current; Instrumentation; Marine predators; Ocean observation; Sea-ice modeling.
Ano: 2008 URL: https://archimer.ifremer.fr/doc/00241/35239/33750.pdf
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