83 resultados para Cálculo de incertezas


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Phosphorus is one of the limiting nutrients for sugarcane development in Brazilian soils. The spatial variability of this nutrient is great, defined by the properties that control its adsorption and desorption reactions. Spatial estimates to characterize this variability are based on geostatistical interpolation. However, inherent uncertainties in the procedure of these estimates are related to the variability structure of the property under study and the sample configuration of the area. Thus, the assessment of the uncertainty of estimates associated with the spatial distribution of available P (Plabile) is decisive to optimize the use of phosphate fertilizers. The purpose of this study was to evaluate the performance of sequential Gaussian simulation (sGs) and ordinary kriging (OK) in the modeling of uncertainty in available P estimates. A sampling grid with 626 points was established in a 200-ha experimental sugarcane field in Tabapuã, São Paulo State. The sGs algorithm generated 200 realizations. The sGs realizations reproduced the statistics and the distribution of the sample data. The G statistic (0.81) indicated good agreement between the values of simulated and observed fractions. The sGs realizations preserved the spatial variability of Plabile without the smoothing effect of the OK map. The accuracy in the reproduction of the variogram of the sample data obtained by the sGs realizations was on average 240 times higher than that obtained by OK. The uncertainty map, obtained by OK, showed less variation in the study area than that obtained by sGs. Thus, the evaluation of uncertainties by sGs was more informative and can be used to define and delimit specific management areas more precisely.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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In this paper we present an alternative approach due to Bondi for the special theory of relativity. During the development, we analyse the Bondi diagrams, visual resources from which we can take some information about the analysed systems, and we discuss the K factor of Bondi's theory, which is in the core of this work. We then discuss some of the main results obtained from Einstein's special theory of relativity such as the time dilation, spatial contraction and simultaneity of spatially separated events, besides the Lorentz transformations. We also show other two important results in physics coming from K calculus: the relativistic linear momentum and the total relativistic energy.

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Pós-graduação em Biometria - IBB

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Ultrasound is the term that describes the sound waves with higher frequencies than human hearing. Ultrasound used in medical diagnosis is a modality based on the use of sound energy and the acoustic properties of the various parts of the body to produce images of stationary and moving tissues. However, despite the ease of use and security that this modality offers for not using ionizing radiation, one should ensure the accuracy and optimum performance of the equipment, which results in precise diagnoses. To accomplish that, periodic quality control tests must be performed, which include: physical and mechanical inspection of the equipment, image uniformity, depth of penetration/visualization, accuracy of distances, axial and lateral resolution, dead zone and doppler sensitivity. This work intends to study a computerized method for calculating the depth of penetration of ultrasound, comparing it to the observerdependent method currently used. The images were collected during the quality control tests of ultrasound equipment. The results of the comparison between the visual and computerized methods were not conclusive for selecting the safest methodology for obtaining the depth of visualization

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The brachytherapy braquiterapia is an x-ray modality radiotherapy in which stamped or halfstamped radioactive sources in format of seeds are used, wires or to one short distance, in contact or implanted to the fabric to be treated. All the treatment modalities require a previous planning. The formalism recommended for calculation of dose was considered by the AAPM for the first TG-43 Report. In it distributions of dose of isolated seeds measured and calculated by Monte Carlo method in water instead of with models half-empiricists. In this work we in accordance with present some preliminary results of the calculation of functions of radial anisotropy and of dose in the distance for seed of 192Ir, wide used in brachytherapy treatments of high tax of dose (HDR), with the aid of the program based on the Monte Carlo method MCNPX v2.50 (Mount Carlo N ParticleeXtended). The materials chosen in the simulation beyond water, had been MS20 and estriado muscle

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This study presents the results from a qualitative resource, based on research-action methodology, which examined the innovate teaching practices implementations in the Calculus I during 2011 year. The analysis of collected data from three used sources – an initial questionnaire, an exploratory-investigative classroom, and an interview with some students at the end of the second semester – reveals that the students had appropriated of the technological recourses, using it as a tool to look for the knowledge. The investigative activities with the use of information technologies made the use of multiple representations in solving mathematical tasks, making the transition of numerical, algebraic and geometrical results possible for the students when they have looking for validation of their hypotheses and conjectures during mathematical problems solving. This works helped in the insertion of new practices in the discipline, and their results validate the proposal presented by the teacher, which is the discipline of Calculus use, whose character is strongly linked to the training content of the student, as a discipline whose can contributed to the pedagogical formation of the graduation student, leading him to know the Mathematical Education possibilities, specially the Mathematical Investigation - Solving Problems, in the outlook of dialogued classes where the teacher assumes the facilitator role and where the students become actives in their pursuit of knowledge

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Not only the progress of the radiotherapy, but also the improve of the dose in the patient with adjusted radiotherapy plannings, calculation of shield, radiometric survey, among others, are responsibilities of the medical physic inside of a sector of radiotherapy. This monograph has as objective to above show some of these cited functions of the medical physicis, starting with a theoretical basement and at as a moment to present the calculations and the results found during a visit in the Institute of Radiotherapy of the Valley of the Paraíba, located in the city of São José dos Campos, and in the Regional Hospital of Taubaté in the period of 2006, 2007 and 2008

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Induction heating is a process closely linked to the concepts of heat transfer. It also covers electromagnetic induction and effect of film. Many companies use this technology in their processes due to the high accuracy that can be obtained at temperatures induced. However the dominance of this technology is not common among Brazilian industries. This involves complex systems of equation and heat exchange in transient conduction, and convection and radiation losses. With this work we seek the ability to analyze which parameters influence over this process and the order of magnitude of time required for heating a cylindrical part

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Radiotherapy in veterinary practice is already known and widely distributed in large specialized centers of developed countries. In early 2000, there were about 30 radiotherapy equipment specifically designed for the veterinary clinic in the United States. In Brazil, the veterinary radiotherapy is still confined to research in universities, where most of the procedures is radiation therapy performed with superficial x-ray machines, with a voltage between 50 and 150 kVp, focus-distance surface (DFS) between 20,0cm and 40,0cm. As that occurs in human medicine, new research strengthens the development and prospects for the use of radiotherapy as a safe option for treating cancer in animals. This paper presents a methodology for calculating the exposure time for superficial radiotherapy procedures in veterinary medicine for small animals (dogs and cats). The dosimetric parameters of X-rays are determined using a spreadsheet tool for Microsoft Office Excel, developed in this paper for a device Dermopan 2, Veterinary Hospital of UNESP in Araçatuba. Using the worksheet helps the veterinarian to determine the time of exposure to radiation determined for each clinical case, optimize the workflow for professionals in veterinary radiotherapy procedures, which often lack the medical physics in team and at the time of radiotherapy. The correct use of spreadsheet decreases the chances of errors in dose rates of radiation, providing a higher quality of care

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This work aims to study several diffusive regimes, especially Brownian motion. We deal with problems involving anomalous diffusion using the method of fractional derivatives and fractional integrals. We introduce concepts of fractional calculus and apply it to the generalized Langevin equation. Through the fractional Laplace transform we calculate the values of diffusion coefficients for two super diffusive cases, verifying the validity of the method

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The paper presents the radiometric parameters determined by the medical physicist during routine radiotherapy planning service in cases of breast cancer . The contours of the breast volume in patients undergoing radiation breast tumors at the Hospital das Clinicas, Faculty of Medicine , UNESP, Botucatu ( HCFMB ) during the year 2012 were analyzed . In order to analyze the influence of physical and radiometric parameters for the determination of the dose distribution of irradiated breast volume , four measurements of isodose curves were prepared in four different heights breast , and compared with the isodose curves plotted computationally . In the routine of planning , the medical physicist must determine the isodose curve that gives the best dose distribution homogeneity in the irradiated volume . The choice of the treatment plan can be done by dedicated computer systems , which require significantly costly investments available services having better financial support . In the Service of Medical Physics , Department of Radiotherapy , HC FMB , we use a two-dimensional software for determination of isodose curves , however , this software is out of date and frequently becomes inoperable due to the lack of maintenance and it is a closed system without feasibility of interference from computer professionals . This fact requires manual preparation of isodose curves , which are subject to uncertainties due to the subjectivity in the clinical interpretation of medical radiation oncologist and medical physicist responsible for planning , plus dispendiar significant calculation time . The choice of the optimal isodose curve depends on the energy of the radiation beam , the geometry and dimensions of the irradiated area . The contours of the breast studied in this work evaluations showed that , for a given energy input , such as the energy of 1.25 MeV of gamma radiation Unit Telecobaltoterapia , the determination of the percentage depth dose ( PDP ) ...

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This study aimed to develop a computer program which systematizes the structural shielding design calculation in diagnostic radiology facilities. For this purpose methodology of the National Council of Radiation Protection and Measurements (NCRP 147[5]) was used. By comparative statistics studies, it was verified if reference parameters values suggested by the US publication correspond to the average national values. The World Wide Web was chosen because of its characteristics as a powerful mean of communication, especially in terms of the wide variety of useful resources and easy access. To compare the reference values of some parameters proposed by NCRP 147 to Brazilian average, studies about the normalized workload per patient, performance of X-ray tube and primary air kerma, unshielded, at one meter from the focal point of the X-ray tube were made. Through this research, relative differences were found. In workload values this differences reached up to 50% in mammography compared to those presented by the NCRP 147; in X-ray tube performance the percentage differences reached 69% in dental radiology, and air kerma results amounted 31% in fluoroscopy. This demonstrates the importance of validation of international protocols to local realities

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This work studies the most commonly used methods and make comparisons and discussions of the findings made by each of them and the results provided by them. The objective of this research was to show that the method of characteristics is currently the most efficient method to perform these simulations because of its broad scope low simplifications, requirement allowing to consider every detail of the pipe and fluid. Manual calculations are performed and also a software capable of calculating this phenomenon for various situations, such as water pump, elevated tanks, valves and quick maneuver was developed. The software is based on the method of characteristics that is currently recommended by ABNT. These methods, and the results are obtained numerically and graphically are adopted pipes and amount of downstream conditions and in which will be applied. The conclusions reached showed that the Allievi method is widely used yet because of its efficiency and quick calculation for simple pipes. The method of characteristics, although a lot of work to be calculated due to the calculation is iterative process and requires a program to use it, is the only one that allows the calculation with all amount to the conditions situations and downstream of all the pipe possibilities found

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Pós-graduação em Engenharia Elétrica - FEIS