Página 1 dos resultados de 5123 itens digitais encontrados em 0.056 segundos

Identifying financial crises in real time

Da Fonseca, Eder Lucio; Ferreira, Fernando F.; Muruganandam, Paulsamy; Cerdeira, Hilda A.
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica Formato: 1386-1392
ENG
Relevância na Pesquisa
65.64%
Following the thermodynamic formulation of a multifractal measure that was shown to enable the detection of large fluctuations at an early stage, here we propose a new index which permits us to distinguish events like financial crises in real time. We calculate the partition function from which we can obtain thermodynamic quantities analogous to the free energy and specific heat. The index is defined as the normalized energy variation and it can be used to study the behavior of stochastic time series, such as financial market daily data. Famous financial market crashes-Black Thursday (1929), Black Monday (1987) and the subprime crisis (2008)-are identified with clear and robust results. The method is also applied to the market fluctuations of 2011. From these results it appears as if the apparent crisis of 2011 is of a different nature to the other three. We also show that the analysis has forecasting capabilities. © 2012 Elsevier B.V. All rights reserved.

Time-Dependent Density-Functional Theory in Massively Parallel Computer Architectures: The Octopus Project

Andrade, Xavier; Alberdi-Rodriguez, Joseba; Strubbe, David A.; Oliveira, Micael J. T.; Nogueira, Fernando; Castro, Alberto; Muguerza, Javier; Arruabarrena, Agustin; Louie, Steven G.; Aspuru-Guzik, Alan; Rubio, Angel; Marques, Miguel A. L.
Fonte: Institute of Physics Publicador: Institute of Physics
Tipo: Artigo de Revista Científica
EN_US
Relevância na Pesquisa
55.76%
Octopus is a general-purpose density-functional theory (DFT) code, with a particular emphasis on the time-dependent version of DFT (TDDFT). In this paper we present the ongoing efforts to achieve the parallelization of octopus. We focus on the real-time variant of TDDFT, where the time-dependent Kohn–Sham equations are directly propagated in time. This approach has great potential for execution in massively parallel systems such as modern supercomputers with thousands of processors and graphics processing units (GPUs). For harvesting the potential of conventional supercomputers, the main strategy is a multi-level parallelization scheme that combines the inherent scalability of real-time TDDFT with a real-space grid domain-partitioning approach. A scalable Poisson solver is critical for the efficiency of this scheme. For GPUs, we show how using blocks of Kohn–Sham states provides the required level of data parallelism and that this strategy is also applicable for code optimization on standard processors. Our results show that real-time TDDFT, as implemented in octopus, can be the method of choice for studying the excited states of large molecular systems in modern parallel architectures.; Chemistry and Chemical Biology

Toward GPU-accelerated Traffic Simulation and Its Real-Time Challenge

Hirabayashi, Manato; Kato, Shinpei; Edahiro, Masato; Sugiyama, Yuki
Fonte: Universidad Carlos III de Madrid Publicador: Universidad Carlos III de Madrid
Tipo: info:eu-repo/semantics/publishedVersion; info:eu-repo/semantics/conferenceObject
Publicado em 04/12/2012 ENG
Relevância na Pesquisa
65.61%
Traffic simulation is a growing domain of computational physics. Many life and industrial applications would benefit from traffic simulation to establish reliable transportation systems. A core challenge of this science research, however, is its unbounded scale of computation. This paper explores an advantage of using the graphics processing unit (GPU) for this computational challenge. We study two schemes of maximizing GPU performance in the context of traffic simulation, and provide some basic experiments. The experimental results show that our GPU implementation improves simulation speed by five times over the traditional CPU implementation. We also discuss that additional orders-ofmagnitude improvements could be achieved by overcoming the current hardware limitation of the GPU.; This work was supported by Grant-in-Aid for Scientific Research 24500058.; REACTION 2012. 1st International workshop on Real-time and distributed computing in emerging applications. December 4th, 2012, San Juan, Puerto Rico.

Enhancing X3DOM Declarative 3D with Rigid Body Physics Support

Stamoulias, Andreas; Malamos, Athanasios G.; Zampoglou, Markos; Brutzman, Don
Fonte: Escola de Pós-Graduação Naval Publicador: Escola de Pós-Graduação Naval
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
65.67%
Given that physics can be fundamental for realistic and interactive Web3D applications, a number of JavaScript versions of physics engines have been introduced during the past years. This paper presents the implementation of the rigid body physics component, as defined by the X3D specification, in the X3DOM environment, and the creation of dynamic 3D interactive worlds. We briefly review the state of the art in current technologies forWeb3D graphics, including HTML5, WebGL and X3D, and then explore the significance of physics engines in building realistic Web3D worlds. We include a comprehensive review of JavaScript physics engine libraries, and proceed to summarize the significance of our implementation while presenting in detail the methodology followed. The results obtained so far from our cross-browser experiments demonstrate that real-time interactive scenes with hundreds of rigid bodies can be constructed and operate with acceptable frame rates, while the allowing the user to maintain the scene control.; The research of this paper is granted by the European Union and the Hellenic General Secretary of Research and Technology under the COOPERATION 2009 / 09SYN-72-956 Framework.

Real-time terahertz imaging using a quantum cascade laser and uncooled microbolometer focal plane array

Behnken, Barry N.
Fonte: Monterey, California: Naval Postgraduate School, 2008. Publicador: Monterey, California: Naval Postgraduate School, 2008.
Formato: xviii, 81 p. : ill. (chiefly col.) ; 28 cm.
Relevância na Pesquisa
65.61%
Real-time imaging in the terahertz (THz) spectral range was achieved using an uncooled, 160x120 pixel infrared microbolometer camera and a milliwatt-scale quantum cascade laser (QCL). By replacing the camera's original focusing optics with a Tsurupica-based lens and minimizing diffraction effects incurred by the QCL output beam, an imaging scheme was developed in which the camera's focal plane array successfully detected wavelengths that are more than an order of magnitude longer than those for which the system is designed. Moreover, the incorporation of parabolic reflecting optics yielded a capability to produce high-resolution images of objects placed within the beam path. Despite the low laser powers employed, this scheme allows high-contrast imaging of various objects concealed by a wide range of nonmetallic materials-confirming the suitability of this technology for homeland security screening applications. Furthermore, the identification of relatively obscure security features in British currency notes suggests that Terahertz imaging could serve a future role as a detection mechanism against assorted counterfeiting practices. An extensive comparative analysis of experimental data produced using two QCLs (resonating at 2.8 and 3.6 THz) provides additional insight into the physics underlying these results...

Crossed-Array Transducer for Real-Time Three-Dimensional Ultrasound Imaging

Joyce, Andrew Waters
Fonte: Quens University Publicador: Quens University
Tipo: Tese de Doutorado
EN; EN
Relevância na Pesquisa
65.66%
Volumetric ultrasound imaging can present numerous advantages to medical diagnostics, such as increased spatial context, better long-term patient tracking, and reduced imaging times. Creating three-dimensional ultrasound systems is complicated by the attendant increase in system complexity that is required to capture the additional data, and by pulse discrimination imposing repetition frequency limits from the fixed speed of sound in tissue. If the same principles utilized in two-dimensional cross-sectional imaging are applied directly to capture a volumetric data set, the electrical interface, system complexity, and acquisition times grow exponentially. An alternative volumetric imaging method that enables real-time three-dimensional ultrasound imaging using a crossed-array structure is presented in this thesis. The crossed-array transducer developed in this thesis makes use of careful material design and optimization to increase sensitivity and eliminate artifacts. A fine-pitch 1-3 piezocomposite has been optimized for performance in this application. This is combined with a novel method for creating intrinsic apodization within the piezoceramic material. Direct manipulation of the material sensitivity was found to be necessary to eliminate an artifact unique to the large defocused aperture being used: range secondary lobes. An acoustic stack has been designed for the transducer that optimizes sensitivity and reduces manufacturing complexity. Traces on a flexible circuit are used to define the array elements and the polyimide substrate is acoustically integrated as a matching layer. A defocusing rubber lens is used to keep the unfocused axis from experiencing near-field effects. Custom electronics are developed that incorporate a pulser and transmit beamforming system. The pulser uses a new circuit topology to create Ohmic grounding of the array elements when inactive. This is necessary in order to use the same substrate for both send and receive. A transmit beamformer and an advanced control interface have been developed that permit flexible testing using computer control...

Diffusion of Real-Time Information in Social-Physical Networks

Qian, Dajun; Yağan, Osman; Yang, Lei; Zhang, Junshan
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
55.75%
We study the diffusion behavior of real-time information. Typically, real-time information is valuable only for a limited time duration, and hence needs to be delivered before its "deadline." Therefore, real-time information is much easier to spread among a group of people with frequent interactions than between isolated individuals. With this insight, we consider a social network which consists of many cliques and information can spread quickly within a clique. Furthermore, information can also be shared through online social networks, such as Facebook, twitter, Youtube, etc. We characterize the diffusion of real-time information by studying the phase transition behaviors. Capitalizing on the theory of inhomogeneous random networks, we show that the social network has a critical threshold above which information epidemics are very likely to happen. We also theoretically quantify the fractional size of individuals that finally receive the message. Finally, the numerical results indicate that under certain conditions, the large size cliques in a social network could greatly facilitate the diffusion of real-time information.; Comment: add one more figure

Synergistic Formation of Radicals by Irradiation with Both Vacuum Ultraviolet and Atomic Hydrogen: A Real-Time In Situ Electron Spin Resonance Study

Ishikawa, Kenji; Sumi, Naoya; Kono, Akihiko; Horibe, Hideo; Takeda, Keigo; Kondo, Hiroki; Sekine, Makoto; Hori, Masaru
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 28/06/2012
Relevância na Pesquisa
55.75%
We report on the surface modification of polytetrafluoroethylene (PTFE) as an example of soft- and bio-materials that occur under plasma discharge by kinetics analysis of radical formation using in situ real-time electron spin resonance (ESR) measurements. During irradiation with hydrogen plasma, simultaneous measurements of the gas-phase ESR signals of atomic hydrogen and the carbon dangling bond (C-DB) on PTFE were performed. Dynamic changes of the C-DB density were observed in real time, where the rate of density change was accelerated during initial irradiation and then became constant over time. It is noteworthy that C-DBs were formed synergistically by irradiation with both vacuum ultraviolet (VUV) and atomic hydrogen. The in situ real-time ESR technique is useful to elucidate synergistic roles during plasma surface modification.; Comment: 14 pages, 4 figures

Real Time Discovery of Dense Clusters in Highly Dynamic Graphs: Identifying Real World Events in Highly Dynamic Environments

Agarwal, Manoj K; Ramamritham, Krithi; Bhide, Manish
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 30/06/2012
Relevância na Pesquisa
55.77%
Due to their real time nature, microblog streams are a rich source of dynamic information, for example, about emerging events. Existing techniques for discovering such events from a microblog stream in real time (such as Twitter trending topics), have several lacunae when used for discovering emerging events; extant graph based event detection techniques are not practical in microblog settings due to their complexity; and conventional techniques, which have been developed for blogs, web-pages, etc., involving the use of keyword search, are only useful for finding information about known events. Hence, in this paper, we present techniques to discover events that are unraveling in microblog message streams in real time so that such events can be reported as soon as they occur. We model the problem as discovering dense clusters in highly dynamic graphs. Despite many recent advances in graph analysis, ours is the first technique to identify dense clusters in massive and highly dynamic graphs in real time. Given the characteristics of microblog streams, in order to find clusters without missing any events, we propose and exploit a novel graph property which we call short-cycle property. Our algorithms find these clusters efficiently in spite of rapid changes to the microblog streams. Further we present a novel ranking function to identify the important events. Besides proving the correctness of our algorithms we show their practical utility by evaluating them using real world microblog data. These demonstrate our technique's ability to discover...

Contrasting Real-time Dynamics with Screening Phenomena at Finite Temperature

Huang, Suzhou; Lissia, Marcello
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
55.77%
We discuss the interpretation of Euclidean correlation functions at finite temperature ($T$) and their relationship with the corresponding real-time Green's functions. The soluble 2+1 dimensional Gross-Neveu model in the large-$N$ limit is used throughout as a working example. First, the real-time bound state, identified as an elementary excitation at finite $T$, is solved. The bound state mass, the dispersion relation at low momenta, the coupling constant and decay constant are calculated. To characterize the structure of the bound state the on-shell form factor is carefully introduced and calculated. Then we examine the corresponding screening state and contrast the screening mass, coupling constant, decay constant and the screening Bethe-Salpeter amplitude with the real-time quantities. We find that, although they can be used as qualitative indicators in the low-$T$ regime, the screening states at finite $T$ in general do not reflect the properties of the corresponding real-time bound states. Besides, other relevant issues, such as the subtlety of the real-time manifestation of conservation laws due to some internal symmetries at $T\ne 0$, the temperature dependence of the pseudoscalar spectral function and its sum rule, and the high-$T$ limit of the screening state and its implications to the dimensional reduction...

Real-time Feynman path integral with Picard--Lefschetz theory and its applications to quantum tunneling

Tanizaki, Yuya; Koike, Takayuki
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
55.76%
Picard--Lefschetz theory is applied to path integrals of quantum mechanics, in order to compute real-time dynamics directly. After discussing basic properties of real-time path integrals on Lefschetz thimbles, we demonstrate its computational method in a concrete way by solving three simple examples of quantum mechanics. It is applied to quantum mechanics of a double-well potential, and quantum tunneling is discussed. We identify all of the complex saddle points of the classical action, and their properties are discussed in detail. However a big theoretical difficulty turns out to appear in rewriting the original path integral into a sum of path integrals on Lefschetz thimbles. We discuss generality of that problem and mention its importance. Real-time tunneling processes are shown to be described by those complex saddle points, and thus semi-classical description of real-time quantum tunneling becomes possible on solid ground if we could solve that problem.; Comment: 24 pages, 9 figures; (v2) Discussion in Sec.4.3 is improved, Figs. 8 and 9 added, typos corrected, references added; (v3) typos corrected

Lattice simulations of real-time quantum fields

Berges, J.; Borsanyi, Sz.; Sexty, D.; Stamatescu, I. -O.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 27/09/2006
Relevância na Pesquisa
55.75%
We investigate lattice simulations of scalar and nonabelian gauge fields in Minkowski space-time. For SU(2) gauge-theory expectation values of link variables in 3+1 dimensions are constructed by a stochastic process in an additional (5th) ``Langevin-time''. A sufficiently small Langevin step size and the use of a tilted real-time contour leads to converging results in general. All fixed point solutions are shown to fulfil the infinite hierarchy of Dyson-Schwinger identities, however, they are not unique without further constraints. For the nonabelian gauge theory the thermal equilibrium fixed point is only approached at intermediate Langevin-times. It becomes more stable if the complex time path is deformed towards Euclidean space-time. We analyze this behavior further using the real-time evolution of a quantum anharmonic oscillator, which is alternatively solved by diagonalizing its Hamiltonian. Without further optimization stochastic quantization can give accurate descriptions if the real-time extend of the lattice is small on the scale of the inverse temperature.; Comment: 36 pages, 15 figures, Latex

Real-time capable first principle based modelling of tokamak turbulent transport

Citrin, J.; Breton, S.; Felici, F.; Imbeaux, F.; Aniel, T.; Artaud, J. F.; Baiocchi, B.; Bourdelle, C.; Camenen, Y.; Garcia, J.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
55.75%
A real-time capable core turbulence tokamak transport model is developed. This model is constructed from the regularized nonlinear regression of quasilinear gyrokinetic transport code output. The regression is performed with a multilayer perceptron neural network. The transport code input for the neural network training set consists of five dimensions, and is limited to adiabatic electrons. The neural network model successfully reproduces transport fluxes predicted by the original quasilinear model, while gaining five orders of magnitude in computation time. The model is implemented in a real-time capable tokamak simulator, and simulates a 300s ITER discharge in 10s. This proof-of-principle for regression based transport models anticipates a significant widening of input space dimensionality and physics realism for future training sets. This aims to provide unprecedented computational speed coupled with first-principle based physics for real-time control and integrated modelling applications.; Comment: 10 pages, 3 figures

Fast Converging Path Integrals for Time-Dependent Potentials II: Generalization to Many-body Systems and Real-Time Formalism

Balaz, Antun; Vidanovic, Ivana; Bogojevic, Aleksandar; Belic, Aleksandar; Pelster, Axel
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
55.75%
Based on a previously developed recursive approach for calculating the short-time expansion of the propagator for systems with time-independent potentials and its time-dependent generalization for simple single-particle systems, in this paper we present a full extension of this formalism to a general quantum system with many degrees of freedom in a time-dependent potential. Furthermore, we also present a recursive approach for the velocity-independent part of the effective potential, which is necessary for calculating diagonal amplitudes and partition functions, as well as an extension from the imaginary-time formalism to the real-time one, which enables to study the dynamical properties of quantum systems. The recursive approach developed here allows an analytic derivation of the short-time expansion to orders that have not been accessible before, using the implemented SPEEDUP symbolic calculation code. The analytically derived results are extensively numerically verified by treating several models in both imaginary and real time.; Comment: 24 pages, 5 figures

Real-time calculations of many-body dynamics in quantum systems

Nakatsukasa, Takashi
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 22/09/2012
Relevância na Pesquisa
55.75%
Real-time computation of time-dependent quantum mechanical problems are presented for nuclear many-body problems. Quantum tunneling in nuclear fusion at low energy is described using a time-dependent wave packet. A real-time method of calculating strength functions using the time-dependent Schroedinger equation is utilized to properly treat the continuum boundary condition. To go beyond the few-body models,we resort to the density-functional theory. The nuclear mean-field models are briefly reviewed to illustrate its foundation and necessity of state dependence in effective interactions. This state dependence is successfully taken into account by the density dependence, leading to the energy density functional. Photoabsorption cross sections in 238U are calculated with the real-time method for the time-dependent density-functional theory.; Comment: 15 pages, 8 figures, Talk at Conference on Computational Physics (CCP2011), Gatlinburg, USA, Oct. 30 - Nov. 3, 2011. arXiv admin note: substantial text overlap with arXiv:1209.4966

Real-time feedback from iterative electronic structure calculations

Vaucher, Alain C.; Haag, Moritz P.; Reiher, Markus
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 21/10/2015
Relevância na Pesquisa
55.8%
Real-time feedback from iterative electronic structure calculations requires to mediate between the inherently unpredictable execution times of the iterative algorithm employed and the necessity to provide data in fixed and short time intervals for real-time rendering. We introduce the concept of a mediator as a component able to deal with infrequent and unpredictable reference data to generate reliable feedback. In the context of real-time quantum chemistry, the mediator takes the form of a surrogate potential that has the same local shape as the first-principles potential and can be evaluated efficiently to deliver atomic forces as real-time feedback. The surrogate potential is updated continuously by electronic structure calculations and guarantees to provide a reliable response to the operator for any molecular structure. To demonstrate the application of iterative electronic structure methods in real-time reactivity exploration, we implement self-consistent semi-empirical methods as the data source and apply the surrogate-potential mediator to deliver reliable real-time feedback.; Comment: 9 pages, 10 figures, 2 tables

Developement of real time diagnostics and feedback algorithms for JET in view of the next step

Murari, A.; Joffrin, E.; Felton, R.; Mazon, D.; Zabeo, L.; Albanese, R.; Arena, P.; Ambrosino, G.; Ariola, M.; Barana, O.; Bruno, M.; Laborde, L.; Moreau, D.; Piccolo, F.; Sartori, F.; Crisanti, F.; De La Luna, E.; Sanchez, J.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
55.76%
Real time control of many plasma parameters will be an essential aspect in the development of reliable high performance operation of Next Step Tokamaks. The main prerequisites for any feedback scheme are the precise real-time determination of the quantities to be controlled, requiring top quality and highly reliable diagnostics, and the availability of robust control algorithms. A new set of real time diagnostics was recently implemented on JET to prove the feasibility of determining, with high accuracy and time resolution, the most important plasma quantities. With regard to feedback algorithms, new model–based controllers were developed to allow a more robust control of several plasma parameters. Both diagnostics and algorithms were successfully used in several experiments, ranging from H-mode plasmas to configuration with ITBs. Since elaboration of computationally heavy measurements is often required, significant attention was devoted to non-algorithmic methods like Digital or Cellular Neural/Nonlinear Networks. The real time hardware and software adopted architectures are also described with particular attention to their relevance to ITER.; Comment: 12th International Congress on Plasma Physics, 25-29 October 2004, Nice (France)

Magnetic circular dichroism in real-time time-dependent density functional theory

Lee, K. -M.; Yabana, K.; Bertsch, G. F.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 18/12/2010
Relevância na Pesquisa
55.76%
We apply the adiabatic time-dependent density functional theory to magnetic ci the real-space, real-time computational method. The standard formulas for the MCD response and its A and B terms are derived from the observables in the time-dependent wave function. We find the real time method is well suited for calculating the overall spectrum, particularly at higher excitation energies where individual excited states are numerous and overlapping. The MCD sum rules are derived and interpreted in the real-time formalism; we find that they are very useful for normalization purposes and assessing the accuracy of the theory. The method is applied to MCD spectrum of C-60 using the adiabatic energy functional from the local density approximation. The theory correctly predicts the signs of the A and B terms for the lowest allowed excitations. However, the magnitudes of the terms only show qualitative agreement with experiment.; Comment: 16 pages, 4 figures, and 1 table

Development of a System for Real-Time Measurements of Metabolite Transport in Plants Using Short-Lived Positron-Emitting Radiotracers

Kiser, Matthew Ryan
Fonte: Universidade Duke Publicador: Universidade Duke
Tipo: Dissertação Formato: 6907695 bytes; application/pdf
Publicado em 29/07/2008 EN_US
Relevância na Pesquisa
55.77%

Over the past 200 years, the Earth's atmospheric carbon dioxide (CO2) concentration has increased by more than 35%, and climate experts predict that CO2 levels may double by the end of this century. Understanding the mechanisms of resource management in plants is fundamental for predicting how plants will respond to the increase in atmospheric CO2. Plant productivity sustains life on Earth and is a principal component of the planet's system that regulates atmospheric CO2 concentration. As such, one of the central goals of plant science is to understand the regulatory mechanisms of plant growth in a changing environment. Short-lived positron-emitting radiotracer techniques provide time-dependent data that are critical for developing models of metabolite transport and resource distribution in plants and their microenvironments. To better understand the effects of environmental changes on resource transport and allocation in plants, we have developed a system for real-time measurements of metabolite transport in plants using short-lived positron-emitting radiotracers. This thesis project includes the design, construction, and demonstration of the capabilities of this system for performing real-time measurements of metabolite transport in plants.

The short-lived radiotracer system described in this dissertation takes advantage of the combined capabilities and close proximity of two research facilities at Duke University: the Triangle Universities Nuclear Laboratory (TUNL) and the Duke University Phytotron...

Design of a gauge pressure sensor for Physics teaching in real time; Projeto de um sensor de pressão manométrica para ensino de física em tempo real

Rocha, Fábio Saraiva da; Universidade Federal de Pelotas; Guadagnini, Paulo Henrique; Universidade Federal do Pampa (Unipampa)
Fonte: Imprensa Universitária - UFSC Publicador: Imprensa Universitária - UFSC
Tipo: info:eu-repo/semantics/article; info:eu-repo/semantics/publishedVersion; Formato: application/pdf
Publicado em 25/11/2013 POR
Relevância na Pesquisa
85.8%
We present the design of a gauge pressure sensor aimed at teaching experimental Physics. This device enables reading the pressure of a gaseous system in comparison to local atmospheric pressure. The sensor consists of a piezoresistive pressure transducer and Arduino development board for digitizing analog readings from the transducer, data processing and digital communication via the USB interface. The pressure sensor provides real time numerical data (Real Time Physics – RTP) for measuring pressure through tables and graphs using the PLX-DAQ data acquisition tool and the Excel spreadsheet. We show the physical and operational characteristics of the MPX4250GP transducer, the general aspects of the Arduino board and we detail the computer programming involved in the entire project. We discuss the performance and limitations of this sensor when compared to a commercial sensor GPS-BTA Vernier brand. The reader can use this device in a practice with illustrative latex balloons arranged in a physical system that can be easily reproduced in an experimental Physics laboratory or even in an ordinary classroom situation. The pressure sensor performance was similar to the commercial sensor GPS-BTA, and it shows promise for the use in Physics teaching practices that seek innovation in the teaching laboratory...