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Projecto, montagem e teste de uma unidade modular de detecção de radiação Geiger-Muller

Cavaleiro, António Pedro Marques Pita
Fonte: Instituto Politécnico de Lisboa Publicador: Instituto Politécnico de Lisboa
Tipo: Dissertação de Mestrado
Publicado em /09/2013 Português
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Esta dissertação apresenta o estudo e o projecto de uma fonte de alimentação para um detector de radiação Geiger-Muller. A fonte de alimentação tanto pode funcionar com a tensão da rede como pode ser integrada em sistemas de electrónica modular NIM de modo a ser facilmente integrada em qualquer tipo de laboratório. A fonte de alimentação inclui os seguintes módulos: 1) rectificador controlado; 2) conversor boost; 3) inversor de tensão; 4) transformador de impulsos; 5) ponte rectificadora de díodos e 6) separador de Alta Tensão – Sinal. Os resultados obtidos experimentalmente estão de acordo com resultados obtidos por simulações usando o Matlab/Simulink ou o OrCAD. Estes resultados permitem demonstrar a fiabilidade e a validade da fonte de alimentação proposta para alimentar o detector Geiger-Muller. A fonte de alimentação foi testada em condições reais de funcionamento com fontes de isótopos radioactivos escolhidos.; This MSc thesis presents the research and project of a power supply for a Geiger-Muller radiation detector. The power supply may work with mains voltage or may be integrated in a NIM module so that can be easily integrated in any kind of laboratory. The power supply includes the following modules: 1) single-phase full wave controlled rectifier; 2) Boost converter; 3) Voltage inverter; 4) pulse transformer; 5) single-phase bridge rectifier and 6) separador de Alta Tensão – Sinal. The results obtained experimentally match the results obtained by simulations using Matlab/Simulink or OrCAD. This results allow to demonstrate the fiability and validate the proposed power supply to connect to the Geiger-Muller detector. The power supply was tested in real conditions of functioning with chosen sources of radioactive isotopes.

Montagem e teste de detector Geiger Muller usando tubo SBM19

Kakuno,Edson Massayuki
Fonte: Sociedade Brasileira de Física Publicador: Sociedade Brasileira de Física
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/03/2014 Português
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Este trabalho descreve a montagem de um detector Geiger Muller (GM) a partir de um tubo comercial, SBM19, e com flexibilidade nos componentes eletrônicos agregados. Muitas referências citadas são de domínio público e disponíveis na internet, permitido ao leitor uma maior facilidade ao acesso às informações e a outras possibilidades de montagem de um detector GM. O detector proposto é uma ferramenta em potencial para o ensino de física moderna no Ensino Médio e uma proposta de demonstração em feiras de ciências. São apresentados resultados de medidas em camisas de lampião, Am de um detector de fumaça e de um cinzeiro enriquecido com urânio.

Simulation of a Geiger-Mode Imaging LADAR System for Performance Assessment

Kim, Seongjoon; Lee, Impyeong; Kwon, Yong Joon
Fonte: MDPI Publicador: MDPI
Tipo: Artigo de Revista Científica
Publicado em 03/07/2013 Português
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As LADAR systems applications gradually become more diverse, new types of systems are being developed. When developing new systems, simulation studies are an essential prerequisite. A simulator enables performance predictions and optimal system parameters at the design level, as well as providing sample data for developing and validating application algorithms. The purpose of the study is to propose a method for simulating a Geiger-mode imaging LADAR system. We develop simulation software to assess system performance and generate sample data for the applications. The simulation is based on three aspects of modeling—the geometry, radiometry and detection. The geometric model computes the ranges to the reflection points of the laser pulses. The radiometric model generates the return signals, including the noises. The detection model determines the flight times of the laser pulses based on the nature of the Geiger-mode detector. We generated sample data using the simulator with the system parameters and analyzed the detection performance by comparing the simulated points to the reference points. The proportion of the outliers in the simulated points reached 25.53%, indicating the need for efficient outlier elimination algorithms. In addition...

Implementação de um Array de detetores de radiação ionizante

Oliveira, Ana Cláudia da Silva
Fonte: Instituto Politécnico do Porto. Instituto Superior de Engenharia do Porto Publicador: Instituto Politécnico do Porto. Instituto Superior de Engenharia do Porto
Tipo: Dissertação de Mestrado
Publicado em //2013 Português
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Atualmente, as radiações ionizantes desempenham um papel fundamental nas áreas de diagnóstico e terapia, estando omnipresentes em ambientes hospitalares. Contudo, devido aos efeitos biológicos adversos da radiação, torna-se essencial a protecção dos profissionais de saúde e pacientes. Consequentemente, um array de detetores capazes de produzir um sinal acústico, aquando da presença de radiação ionizante excedendo determinados valores limite e transmissão via wireless das leituras para um sistema central _e de grande interesse prático. Nesta dissertação, foi implementado um sistema capaz de alimentar um array de sensores de radiação para monitorização de diferentes espaços e transmissão das leituras efetuadas via wireless. A aquisição de dados foi realizada, recorrendo à utilização de um conversor analógico-digital. Vários testes de validação foram realizados, através de vários passos para alcançar a concretização do sistema final, nomeadamente testes relativos ao circuito de detecção, módulos de comunicação wireless, bem como o uso de diferentes ambientes de desenvolvimento integrados (IDE). Os resultados destes testes mostram a visualização e gravação adequadas dos dados relativos aos níveis de radiação...

Educational cosmic ray experiments with Geiger counters

Blanco, F.; Fichera, F.; La Rocca, P.; Librizzi, F.; Parasole, O.; Riggi, F.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 31/12/2006 Português
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Experiments concerning the physics of cosmic rays offer to high-school teachers and students a relatively easy approach to the field of research in high energy physics. The detection of cosmic rays does not necessarily require the use of sophisticated equipment, and various properties of the cosmic radiation can be observed and analysed even by the use of a single Geiger counter. Nevertheless, the variety of such kind of experiments and the results obtained are limited because of the inclusive nature of these measurements. A significant improvement may be obtained when two or more Geiger counters are operated in coincidence. In this paper we discuss the potential of performing educational cosmic ray experiments with Geiger counters. In order to show also the educational value of coincidence techniques, preliminary results of cosmic ray experiments carried out by the use of a simple coincidence circuit are briefly discussed.; Comment: 14 pages, 7 figures

Geiger-Mode Avalanche Photodiodes in Particle Detection

Vilella, E.; Alonso, O.; Trenado, J.; Vilà, A.; Vos, M.; Garrido, L.; Diéguez, A.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 27/01/2012 Português
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It is well known that avalanche photodiodes operated in the Geiger mode above the breakdown voltage offer a virtually infinite sensitivity and time accuracy in the picosecond range that can be used for single photon detection. However, their performance in particle detection remains still unexplored. In this contribution, we are going to expose the different steps that we have taken in order to prove the efficiency of Geiger mode avalanche photodiodes in the aforementioned field. In particular, we will present an array of pixels of 1mmx1mm fabricated with a standard CMOS technology for characterization in a test beam.; Comment: 7 pages, 2 figures, Proceedings of LCWS11

Multi-pixel Geiger-mode avalanche photodiode and wavelength shifting fibre readout of plastic scintillator counters of the EMMA underground experiment

Akhrameev, E. V.; Bezrukov, L. B.; Dzaparov, I. M.; Davitashvili, I. Sh.; Enqvist, T.; Fynbo, H.; Guliev, Zh. Sh.; Inzhechik, L. V.; Izmaylov, A. O.; Joutsenvaara, J.; Khabibullin, M. M.; Khotjantsev, A. N.; Kudenko, Yu. G.; Kuusiniemi, P.; Lubsandorzhiev
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 29/01/2009 Português
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The results of a development of a scintillator counter with wavelength shifting (WLS) fibre and a multi-pixel Geiger-mode avalanche photodiode readout are presented. The photodiode has a metal-resistor-semiconductor layered structure and operates in the limited Geiger mode. The scintillator counter has been developed for the EMMA underground cosmic ray experiment.; Comment: 4 pages, 8 figures

Commercially available Geiger mode single-photon avalanche photodiode with a very low afterpulsing probability

Stipčević, Mario
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 17/05/2015 Português
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Afterpulsing is one of the main technological flaws present in photon counting detectors based on solid-state semiconductor avalanche photodiodes operated in Geiger mode. Level of afterpulsing depends mainly on type of the semiconductor, doping concentrations and temperature and presents an additional source of noise, along with dark counts. Unlike dark counts which appear randomly in time, aterpulses and are time-correlated with the previous detections. For measurements that rely on timing information afterpulsing can create fake signals and diminish the sensitivity. In this work we test a novel broadband sensitive APD that was designed for sub-Geiger avalanche gain operation. We find that this APD, which has a reach-through geometry typical of single-photon detection photodiodes, can also operate in Geiger mode with usable detection sensitivity and acceptable dark counts level while exhibiting uniquely low afterpulsing. The afterpulsing of tested samples was systematically less than 0.05 percent at 10V excess voltage.; Comment: 3 pages, 1 figure

Characterization of silicon Geiger-mode avalanche photodiodes with novel device architecture

Kolb, Kimberly
Fonte: Rochester Instituto de Tecnologia Publicador: Rochester Instituto de Tecnologia
Tipo: Tese de Doutorado
Português
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Geiger-mode avalanche photodiode (GM APD) detectors are capable of counting single photons, measuring arrival times with high resolution, and generating zero read noise (when operated with a CMOS digital readout circuit) due to their unique internal gain characteristics. These capabilities make them exceptionally suited to tasks that require precise arrival time measurements or characterization of faint signals (low photon flux). Laser ranging systems use their arrival time measurement capabilities to build three-dimensional images, while adaptive optics applications have recently begun to capitalize on their low noise and high-speed operation for correcting wavefront imperfections due to atmospheric interference. There is now growing interest in using GM APDs for imaging applications where accurate measurements of faint signals are necessary, such as in astronomy. MIT Lincoln Laboratory and the RIT Center for Detectors have developed silicon GM APDs with unique architecture, utilizing scupper regions to minimize detector noise. This thesis investigates the performance of these detectors in terms of dark count rate (DCR). There are a number of mechanisms that produce dark counts, the most prominent being thermal excitation of carriers. Thermal carrier generation rates are generally only dependent on the temperature of the diode and may be constant under certain controlled conditions. Afterpulsing results from the release of carriers trapped in intermediate energy states (states with energy in the band gap of the material). Unlike thermal carrier generation...

On the uncertainty of sea-ice isostasy

Geiger, Cathleen; Wadhams, Peter; Müller, Hans-Reinhard; Richter-Menge, Jacqueline; Samluk, Jesse; Deliberty, Tracy; Corradina, Victoria
Fonte: International Glaciological Society Publicador: International Glaciological Society
Tipo: Artigo de Revista Científica
Português
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Publisher's PDF; During late winter 2007, coincident measurements of sea ice were collected using various sensors at an ice camp in the Beaufort Sea, Canadian Arctic. Analysis of the archived data provides new insight into sea-ice isostasy and its related R-factor through case studies at three scales using different combinations of snow and ice thickness components. At the smallest scale (<1 m; point scale), isostasy is not expected, so we calculate a residual and define this as

Impact of spatial aliasing on sea-ice thickness measurements

Geiger, Cathleen; Müller, Hans-Reinhard; Samluk, Jesse P.; Bernstein, E. Rachel; Richter-Menge, Jacqueline
Fonte: International Glaciological Society Publicador: International Glaciological Society
Tipo: Artigo de Revista Científica
Português
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Publisher's PDF; We explore spatial aliasing of non-Gaussian distributions of sea-ice thickness. Using a heuristic model and >1000 measurements, we show how different instrument footprint sizes and shapes can cluster thickness distributions into artificial modes, thereby distorting frequency distribution, making it difficult to compare and communicate information across spatial scales. This problem has not been dealt with systematically in sea ice until now, largely because it appears to incur no significant change in integrated thickness which often serves as a volume proxy. Concomitantly, demands are increasing for thickness distribution as a resource for modeling, monitoring and forecasting air–sea fluxes and growing human infrastructure needs in a changing polar environment. New demands include the characterization of uncertainties both regionally and seasonally for spaceborne, airborne, in situ and underwater measurements. To serve these growing needs, we quantify the impact of spatial aliasing by computing resolution error (Er) over a range of horizontal scales (x) from 5 to 500 m. Results are summarized through a power law (Er = bxm) with distinct exponents (m) from 0.3 to 0.5 using example mathematical functions including Gaussian...

Full-physics 3-D heterogeneous simulations of electromagnetic induction fields on level and deformed sea ice

Samluk, Jesse P.; Geiger, Cathleen A.; Weiss, Chester J.
Fonte: International Glaciological Society Publicador: International Glaciological Society
Tipo: Artigo de Revista Científica
Português
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Publisher's PDF; In this paper we explore simulated responses of electromagnetic (EM) signals relative to in situ field surveys and quantify the effects that different values of conductivity in sea ice have on the EM fields. We compute EM responses of ice types with a three-dimensional (3-D) finite-volume discretization of Maxwell’s equations and present 2-D sliced visualizations of their associated EM fields at discrete frequencies. Several interesting observations result: First, since the simulator computes the fields everywhere, each gridcell acts as a receiver within the model volume, and captures the complete, coupled interactions between air, snow, sea ice and sea water as a function of their conductivity; second, visualizations demonstrate how 1-D approximations near deformed ice features are violated. But the most important new finding is that changes in conductivity affect EM field response by modifying the magnitude and spatial patterns (i.e. footprint size and shape) of current density and magnetic fields. These effects are demonstrated through a visual feature we define as ‘null lines’. Null line shape is affected by changes in conductivity near material boundaries as well as transmitter location. Our results encourage the use of null lines as a planning tool for better ground-truth field measurements near deformed ice types.; University of Delaware. Department of Geography.; University of Delaware. Department of Electrical and Computer Engineering.

Antarctic sea-ice thickness and volume estimates from ice charts between 1995 and 1998

Bernstein, E. Rachel; Geiger, Cathleen A.; Deliberty, Tracy L.; Lemcke-Stampone, Mary D.
Fonte: International Glaciological Society Publicador: International Glaciological Society
Tipo: Artigo de Revista Científica
Português
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Publisher's PDF; This work evaluates two distinct calculations of central tendency for sea-ice thickness and quantifies the impact such calculations have on ice volume for the Southern Ocean. The first calculation, area-weighted average thickness, is computed from polygonal ice features and then upscaled to regions. The second calculation, integrated thickness, is a measure of the central value of thickness categories tracked across different scales and subsequently summed to chosen regions. Both methods yield the same result from one scale to the next, but subsequent scales develop diverging solutions when distributions are strongly non-Gaussian. Data for this evaluation are sea-ice stage-ofdevelopment records from US National Ice Center ice charts from 1995 to 1998, as proxy records of ice thickness. Results show regionally integrated thickness exceeds area-weighted average thickness by as much as 60% in summer with as few as five bins in thickness distribution. Year-round, the difference between the two calculations yields volume differences consistently >10%. The largest discrepancies arise due to bimodal distributions which are common in ice charts based on current subjective-analysis protocols. We recommend that integrated distribution be used for regional-scale sea-ice thickness and volume estimates from ice charts and encourage similar testing of other large-scale thickness data archives.; University of Delaware. Department of Geography.

Spatial and temporal characterization of sea-ice deformation

Hutchings, J. K.; Roberts, A.; Geiger, Cathleen A.; Richter-Menge, Jacqueline A.
Fonte: International Glaciological Society Publicador: International Glaciological Society
Tipo: Artigo de Revista Científica
Português
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Final published version; In late March 2007 an array of GPS ice drifters was deployed in the Beaufort Sea as part of the Sea Ice Experiment: Dynamic Nature of the Arctic (SEDNA). The drifters were deployed in an array designed to resolve four, nested spatial scales of sea-ice deformation, from 10 to 140 km, with the arrays maintaining appropriate shape for strain-rate calculation until mid-June. In this paper, we test whether sea-ice deformation displays fractal properties in the vicinity of SEDNA. We identify that deformation time series have different spectral properties depending on the spatial scale. At the scales around 100 km, deformation is a red-noise process, indicating the importance of the ice-pack surface forcing in determining the deformation rate of sea ice at this scale. At smaller scales, the deformation becomes an increasingly whiter process (it has pink noise properties), which suggests an increasing role of dissipative processes at smaller scales. At spatial scales of 10-100 km, and sub-daily scales, there is no deformation coherence across scales; coherence only becomes apparent at longer scales greater than 100 km. The lack of coherence at small scales aids in understanding previous observations where correlation between 10 km regions adjacent to each other varied widely...

Large-scale sea ice drift and deformation: Comparison between models and observations in the western weddell sea during 1992

Geiger, Cathleen A.; Hibler, W. D., III; Ackley, Stephen F.
Fonte: American Geophysical Union Publicador: American Geophysical Union
Tipo: Artigo de Revista Científica
Português
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Final published version; Statistical comparisons between numerical sea ice models and an observed large-scale strain array in the western Weddell Sea during 1992 are used to evaluate the performance of three of the more generally utilized sea ice rheology formulations. Results show that sea ice velocity is reproduced with relatively high accuracy (90% coherence, >80% normalized cross correlation) in models having high-quality atmospheric forcing fields (e.g., the European Centre for Medium-Range Weather Forecasts). On the other hand, temporal and spatial variability of the velocity field, as exemplified by progressive vector plots and ice deformation, respectively, are reproduced less accurately (coherence and normalized cross correlation <50%). In terms of model sensitivity, this means that deformation and temporal variability are more discriminating in terms of elucidating specifics about the constitutive relation and mechanical properties of sea ice on a large scale. For example, inclusion of both compressive and shear stresses is important in attaining a proper probability distribution of deformation relative to observations. Additional analysis shows that adjustments to specific model parameters improve the model results for either drift or select deformation components...

Large-scale comparison between buoy and SSM/I drift and deformation in the eurasian basin during winter 1992-1993

Geiger, Cathleen A.; Zhao, Y. H.; Liu, A. K.; Hakkinen, S.
Fonte: American Geophysical Union Publicador: American Geophysical Union
Tipo: Artigo de Revista Científica
Português
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Final published version; A method for comparing sea ice velocity, divergence, and shear at the large-scale between buoys and Special Sensor Micro wave Imager (SSM/I) is presented. For initial testing, the method is applied in the Eurasian Basin because of its relatively simple circulation dominated by the wind. Using eight Argos buoys, 11 strain rate arrays 100-600 km in size are constructed. Daily 100 km resolution sea ice motion derived from SSM/I 85 GHz brightness temperatures is sampled 100-1000 km from the center of the buoy arrays. Over this range of possible scales, a minimum RMS difference (RMSD) for deformation is used to identify an optimal inclusion radius of 600 km corresponding to a length scale of 1000 km. This length scale is typical of local storms confirming a strong connection between wind and observed sea ice motion. On the basis of all II arrays, an average RMSD of 2.48 +/- 0.05 cm s(-1) for velocity vector and 8.8 +/- 0.9 x 10(-8) s(-1) using all four deformation components (partial derivative u(i)/partial derivative x(j)) is found at the optimal inclusion radius corresponding to average correlation coefficients of 0.896 +/- 0.002 and 0.729 +/- 0.030, respectively. RMSD are found to scale with the temporal and spatial uncertainties of the SSM/I suggesting that even better results can be achieved with higher resolution instruments.; University of Delaware. Department of Geography.

Simulated low-frequency modes of circulation in the Arctic Ocean

Hakkinen, S.; Geiger, Cathleen A.
Fonte: American Geophysical Union Publicador: American Geophysical Union
Tipo: Artigo de Revista Científica
Português
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Final published version; The variability of the Arctic circulation is investigated for a 43 year period (1951-1993) from a coupled ice-ocean model. Empirical orthogonal function (EOF) analysis shows that the variability of the sea surface height (SSH) and vertically integrated transport is organized so that in the leading mode the whole Arctic operates as a single gyre. The mode is associated with the Arctic Oscillation (AO) [Thompson and Wallace, 1998], and it explains over 70% of the variance in the vertically integrated transport and 25% of the SSH variability. The physical interpretation of this mode is derived to arise from its close connection to the Atlantic inflow to the Arctic. The mode shows a major shift toward cyclonic circulation in the end of the 1980s which is associated with a large multiyear pulse of Atlantic water to the Arctic. Thus this event appears as the likely initiation of the Atlantic laver warming observed during the recent years [Carmack et al., 1995]. Overall, the first mode shows strong decadal variability as reported by Proshurinsky and Johnson [1997]. The second mode of the oceanic circulation, which explains 9% of the variance in the transport, contains mio gyres with opposing cyclonicity in the Eurasia and Canada basins. It projects onto the North Atlantic Oscillation (NAO) pattern and displays a 14 year cycle which is known to exist in the midlatitude North Atlantic surface temperatures [Deser and Blackmon...

Coincident buoy- and SAR-derived surface fluxes in the western Weddell Sea during Ice Station Weddell 1992

Drinkwater, M. R.; Geiger, Cathleen A.
Fonte: American Geophysical Union Publicador: American Geophysical Union
Tipo: Artigo de Revista Científica
Português
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Final published version; We examine sea ice kinematics relevant to surface fluxes using ERS-1 synthetic aperture radar (SAR) images coincident with buoys in the western Weddell Sea in austral autumn of 1992. Careful matching of temporal and spatial scales shows that buoy- and SAR-derived velocities differ in root-mean-square error (RMSE) by 0.6 cm s(-1) and 7.80 degrees in magnitude and direction, respectively. These values represent agreements of 91.3% and 92.7%, respectively, and correspond to instrument uncertainties. Scaling analysis shows that shear matching is best at the smallest scales (<= 5 km), while divergence is better represented at scales of 40 km and larger. Sensitivity to error propagation shows lower agreement for divergence (47.4%; RMSE = 7.46 x 10-(8) s(-1)), but we find these results sufficient for integrated surface flux comparisons. Using a toy model, we test the effects of aliasing in surface flux determination. The results show that variability associated with storms, ocean tides, inertial oscillations, and other high-frequency forcing affects integrated sea ice growth rates along this continental slope location. Integrated salt and new ice production rates computed from buoys are found to be two times larger than those computed from ERS-1 SAR motion products. We show that these differences in salt and ice production rates result primarily from inadequate temporal resolution of heat flux variability and sea ice divergence. Comparison with other studies shows that the problem is widespread...

Thickness distribution of Antarctic sea ice

Worby, A. P. (Anthony P.); Geiger, Cathleen A.; Paget, M. J.; Van Woert, Michael L.; Ackley, Stephen F.; DeLiberty, T. L.
Fonte: American Geophysical Union Publicador: American Geophysical Union
Tipo: Artigo de Revista Científica
Português
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Final published version; Ship-based observations are used to describe regional and seasonal changes in the thickness distribution and characteristics of sea ice and snow cover thickness around Antarctica. The data set comprises 23,373 observations collected over more than 2 decades of activity and has been compiled as part of the Scientific Committee on Antarctic Research (SCAR) Antarctic Sea Ice Processes and Climate (ASPeCt) program. The results show the seasonal progression of the ice thickness distribution for six regions around the continent together with statistics on the mean thickness, surface ridging, snow cover, and local variability for each region and season. A simple ridge model is used to calculate the total ice thickness from the observations of level ice and surface topography, to provide a best estimate of the total ice mass, including the ridged component. The long-term mean and standard deviation of total sea ice thickness (including ridges) is reported as 0.87 +/- 0.91 m, which is 40% greater than the mean level ice thickness of 0.62 m. Analysis of the structure function along north/south and east/west transects revealed lag distances over which sea ice thickness decorrelates to be of the order of 100-300 km, which we use as a basis for presenting near-continuous maps of sea ice and snow cover thickness plotted on a 2.5 degrees x 5.0 degrees grid.; University of Delaware. Department of Geography.

Utilização de métodos computacionais no ensino: a experiência de Geiger e Marsden do espalhamento de partículas alfa

Paes, Carlos Eduardo de B.; PUC/SP - São Paulo; Vicente, Victor Emmanuel José de Sousa; PUC/SP - São Paulo; Terini, Ricardo Andrade; PUC - São Paulo; Cavalcante, Marisa Almeida; PUC/SP - São Paulo
Fonte: Imprensa Universitária - UFSC Publicador: Imprensa Universitária - UFSC
Tipo: info:eu-repo/semantics/article; info:eu-repo/semantics/publishedVersion; Formato: application/pdf
Publicado em 01/01/1994 Português
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O presente trabalho descreve o programa GEIGER 1.0, que ilustra a experiência realizada por H. Geiger e E. Marsden em 1909 para a análise da distribuição angular do espalhamento de partículas a por folhas metálicas finas. Através de tal experiência foi possível idealizar um modelo para os átomos que incluía a idéia de um núcleo com determinadas características. O software, descrito com detalhes, baseia-se na teoria de Rutherford e permite, entre outras coisas, comparar as suas previsões com os resultados experimentais obtidos por Geiger e Marsden.