Research of Distorted Vehicle Magnetic Signatures Recognitions, for Length Estimation in Real Traffic Conditions

Reliable cost-effective traffic monitoring stations are a key component of intelligent transportation systems (ITS). While modern surveillance camera systems provide a high amount of data, due to high installation price or invasion of drivers’ personal privacy, they are not the right technology. Therefore, in this paper we introduce a traffic flow parameterization system, using a built-in pavement sensing hub of a pair of AMR (anisotropic magneto resistance) magnetic field and MEMS (micro-electromechanical system) accelerometer sensors. In comparison with inductive loops, AMR magnetic sensors are significantly cheaper, have lower installation price and cause less intrusion to the road. The developed system uses magnetic signature to estimate vehicle speed and length. While speed is obtained from the cross-correlation method, a novel vehicle length estimation algorithm based on characterization of the derivative of magnetic signature is presented. The influence of signature filtering, derivative step and threshold parameter on estimated length is investigated. Further, accelerometer sensors are employed to detect when the wheel of vehicle passes directly over the sensor, which cause distorted magnetic signatures. Results show that even distorted signatures can be used for speed estimation, but it must be treated with a more robust method. The database during the real-word traffic and hazard environmental condition was collected over a 0.5-year period and used for method validation.

Casing Integrity Evaluation in Complex Subsurface Intervention Abandonment Wells Using Magnetic Ranging

This paper describes how active and passive magnetic ranging logging used while drilling subsurface intervention wells shows characteristics of the target well casing integrity and damage. Over the course of the development of a novel active magnetic ranging system and through several years of commercial application, data has been collected and analyzed to understand the characteristics of casing damage. This paper explains the methods used in field operations to collect this data. Using the gathered information, various stages of casing damage and poor integrity are shown. Results obtained from active and passive magnetic ranging are presented in the context of identifying casing damage. This is a departure from the standard methods of interpreting the data as it is not focused on locating a wellbore but determining the integrity of the casing. Casing integrity in idle wells is usually understood by conventional logging techniques until there is a restriction or damage on the well. Magnetic ranging logging performed during the intervention to abandon these wells can give an indication to operators of the casing integrity that otherwise would have been unknown without access to the damaged well. This can help optimize subsequent abandonment procedures as well as assist with field planning into the future to mitigate issues stemming from casing integrity and to identify the causes of previously unknown critical casing damage. The paper reports surface experimental data and compares it with two field examples. In the first field example, the passive magnetic interference from a hundred-year-old casing in the offset well caused more than 100000nT deviation from the reference field approximately 1ft away from the offset well, suggesting severe casing damage. The active magnetic signature measured simultaneously approaches zero, pointing to a lack of electrical continuity in the offset casing caused by a complete break. The second field example shows an offset well segment with passive interference of 7000nT in the presence of a stable active magnetic signal at approximately 2ft separation between wells due to possible casing damage without complete separation. The passive interference increases to 14000 nT at deeper depth while the active signal approaches zero due to a complete casing break. Novel application using the data collected by active and passive magnetic ranging techniques is being applied for the understanding of issues related to casing integrity.

Magnetic Signature of the Saco do Mamanguá and Paraty-Mirim Cove, Rio de Janeiro, Brazil

ABSTRACT. In this work, we investigate the N40°-50°E-oriented magnetic lineaments observed in the marine and aeromagnetic data from the Paraty-Mirim and Saco do Mamanguá (RJ) coves. The main characteristic of these lineaments is the presence of normal and reverse magnetic polarity, indicating that the bodies responsible for the anomalies may be of different ages or have suffered remagnetization effects by metamorphism or have distinct lithologies. The interpretative model of the anomalies was obtained by the 3D Magnetization Vector Inversion (MVI) and by the study of the geology and tectonics of the area. Our results suggest, as a more likely hypothesis, that the magnetic lineaments can be correlated with two tholeiitic dykes swarms, Resende-Ilha Grande and Serra do Mar, which have intruded the region at different times. The age formation of those swarms can be placed at time intervals where the Earth's magnetic field has normal and reverse polarities. The contrasts of magnetic susceptibility obtained from the models are consistent with contrasts of the lithology of basic dykes intruded in the gneissic-granitic basement of the region. Keywords: magnetization vector inversion, magnetic properties, magnetic lineaments, remanent magnetization, tholeiitic dykes swarms Assinatura Magnética do Saco do Mamanguá e da Enseada de Paraty-Mirim, Rio de Janeiro, BrasilRESUMO. Neste trabalho, investigamos os lineamentos magnéticos orientados a N40°-50°E observados nos dados marinhos e aeromagnéticos das enseadas de Paraty-Mirim e do Saco do Mamanguá (RJ). A principal característica destes lineamentos é a presença de polaridade magnética normal e reversa, indicando que os corpos responsáveis pelas anomalias podem ter idades diferentes ou terem sofrido efeitos de remagnetização por metamorfismo ou apresentarem litologias distintas. O modelo interpretativo das anomalias foi obtido pela Inversão do Vetor de Magnetização (IVM) 3D e pelo estudo da geologia e tectônica da área. Nossos resultados sugerem, como hipótese mais provável, que os lineamentos magnéticos podem ser correlacionados com dois enxames de diques toleíticos, Resende-Ilha Grande e Serra do Mar, que têm idades diferentes de intrusão. As idades de formação desses enxames podem ser colocadas em intervalos de tempo em que o campo magnético da Terra apresentou polaridades normal e reversa. Os contrastes de susceptibilidade magnética obtidos no modelo são coerentes com os contrastes de litologia de diques básicos intrudidos no embasamento granítico-gnáissico da região.Palavras-chave: inversão do vetor de magnetização, propriedades magnéticas, lineamentos magnéticos, magnetização remanente, enxames de diques toleíticos

Stellar Turbulent Convection: The Multiscale Nature of the Solar Magnetic Signature

The multiscale dynamics associated with turbulent convection present in physical systems governed by very high Rayleigh numbers still remains a vividly disputed topic in the community of astrophysicists, and in general, among physicists dealing with heat transport by convection. The Sun is a very close star for which detailed observations and estimations of physical properties on the surface, connected to the processes of the underlying convection zone, are possible. This makes the Sun a unique natural laboratory in which to investigate turbulent convection in the hard turbulence regime, a regime typical of systems characterized by high values of the Rayleigh number. In particular, it is possible to study the geometry of convection using the photospheric magnetic voids (or simply voids), the quasi-polygonal quiet regions nearly devoid of magnetic elements, which cover the whole solar surface and which form the solar magnetic network. This work presents the most extensive statistics, both in the spatial scales studied (1–80 Mm) and in the temporal duration (SC 23 and SC 24), to investigate the multiscale nature of solar magnetic patterns associated with the turbulent convection of our star. We show that the size distribution of the voids, in the 1–80 Mm range, for the 317,870 voids found in the 692 analyzed magnetograms, is basically described by an exponential function.