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The induced voltage on underground pipelines is a critical parameter to consider for equipment and personnel safety in the field. However, in the real life, such induced voltage estimation on pipelines is difficult especially at the transmission line planning and routing stage. In this article, several factors affecting the induced voltage on underground pipelines due to inductive coupling with nearby transmission lines are investigated. These factors include the angle and separation distance between transmission lines and pipelines, the length of transmission lines and pipelines, and the soil model. A peak induced voltage calculation formula as the function of the angle and separation distance is derived through surface fitting of simulation data. It is proved in the article that other factors, such as the length of the transmission line and the soil model types, do not have significant influence on the peak induced voltage values on underground pipelines. [ABSTRACT FROM AUTHOR]

Numerical dosimetry makes it possible to evaluate the influence of electromagnetic fields on the human body. The interest of performing numerical dosimetry starting from data coming from general purpose software or measurements is constantly growing. This paper compares two available methods that make dosimetry starting from the knowledge of the magnetic flux density. The quality of results is analyzed considering both exact and uncertain inputs stressing out when one method should be preferred over the other. Finally, the methods are validated using real measurements obtaining good results. [ABSTRACT FROM AUTHOR]

The paper discusses the development status of the inductive power transmission for automotive applications. This technology is, in fact, gaining the interest of electric vehicle manufacturers as an effective strategy to improve the market penetration of electric mobility. Starting from the origin of this technology, the paper presents an overview of the current state of the art as well as the current research and industrial projects. Particular attention is devoted to the description of a prototypal system for the dynamic inductive power transmission whose goal is to extend the battery range by a fast partial recharging during the movement of the vehicle. [ABSTRACT FROM AUTHOR]

Common solids (e.g., flour, sugar, etc.,) can be suspended and transported in air via pneumatic conveying systems. Finely divided solid substances dispersed into a dust cloud (e.g., into a silo) can form a potential explosive atmosphere, if in the right concentration with the oxidizing agent (e.g., air). In addition, it is known that the pneumatic handling of substance, which allows its transport at a certain velocity, can generate static charges; thus, a possible competent ignition source may be also created. In this paper, the causation of an actual dust explosion involving a flour silo being loaded from a tank truck through pneumatic conveying systems in an industrial plant is analyzed. The mechanisms of static discharge applicable to the case in question are discussed, in light of both actual empirical data collected at the incident site, and theory. To fully explain the events that led to the explosion, plausible hypotheses and alternative to static discharge were also evaluated. [ABSTRACT FROM PUBLISHER]

This paper proposes a methodology for the assessment of the human exposure to magnetic fields generated by dynamic inductive power transfer systems for automotive applications. Since the magnetic field is pulsed, current safety standards and guidelines require the use of time-domain approaches to evaluate the peak exposure, which has to be limited under the prescribed limits. This paper shows that, for these kind of systems, the peak exposure can be efficiently evaluated by means of a time-harmonic formulation. Furthermore, a methodology to identify the worst case scenario is proposed and applied to a real case. [ABSTRACT FROM AUTHOR]

Magnetic resonance imaging systems are sensitive to heating: hot spots can lead to a degradation of the image quality and system failure. Gradient coils are required to produce highly uniform and fast switching magnetic fields in order to spatially encode samples within a volume. When optimizing for heating and power loss there is a tradeoff for ideal magnetic performance. This paper investigates an automatic design procedure for gradient coil cooling systems which allows a strict relation between gradient coil design, performed through different criteria power and energy oriented, and its optimal cooling layout. Power and energy optimized split gradient coils are both cooled using an optimized layout based on a Dijkstra’s algorithm approach. Both systems see a large reduction in temperature values allowing the magnetically optimized coil to be used despite its increased power loss. This method can help ensure gradient coils can be optimized primarily for magnetic performance while keeping excess heating under control. [ABSTRACT FROM AUTHOR]

Manual metal arc welding can be a hazardous practice if proper precautions are not taken. The welding procedure uses an open electric arc between an electrode and the metals to be joined. Besides the obvious risks of burns and inflammation of the cornea, which are prevented by using proper personal protective equipment, the operator may also be subject to the risk of electric shock from the exposed parts of the welding circuit, both the electrode and the workpiece. In addition, the welding current, by straying from the intended path, can cause localized heating of parts, with the risks of triggering fires and/or explosive atmospheres. Because of the high current required by the arc welding equipment, operators are exposed also to strong electromagnetic fields. This paper seeks to clarify the aforementioned issues, especially in light of the fact that the risk associated with electric shocks may be unknown to welders and their supervisors. [ABSTRACT FROM PUBLISHER]

In the case of direct or indirect contact with electrically energized parts, an electric current circulates through the body. When the magnitude and duration of the current through the heart exceed the ventricular fibrillation thresholds, the cardiac muscle starts uncoordinated contractions, greatly jeopardizing the life of the subject. Technical standards on electrical installations describe the protective measures against direct and indirect contact necessary to minimize the probability of inception of ventricular fibrillation. Safety considerations are based on experiments made in the past on animals, but the extrapolation of results to human beings is complex and rather questionable. The purpose of this study is to analyze the body factors that affect the distribution of currents passing through the human body with virtual anatomical models. A set of 16 models of individuals is used to simulate different electric contacts. The use of virtual models of a diverse population (i.e., eight males and eight females, ten adults and six children) provides a statistical support to the results. The obtained heart-current factors, are compared with values present in the literature. This paper provides a novel viewpoint on the problem, and supports the ongoing research activity and efforts to improve the electrical safety of persons. [ABSTRACT FROM PUBLISHER]

Objective: The aim of this study is to mitigate intra-gradient coil eddy currents in a hybrid MRI-LINAC system. Methods: The tracks of the gradient coils are modified by cutting slits along the current flow direction. The electromagnetic model developed was first experimentally validated and then used to study the impacts of the slit conductors on the energized and surrounding coils. In this study, gradient coils were slit with different numbers of sub-tracks and driven by a current with frequencies ranging from 100 Hz to 10 kHz. The proposed configuration was assessed by evaluating a number of system parameters, such as the gradient magnetic field, the power loss generated in the surrounding unenergized coil (hereafter referred to as passive coils), and the performance of the energized coil. Results: It was found that at a typical operating frequency of 1 kHz and compared with a conventional (no cut) split coil structure, the new coil pattern (with four slits) offered improved coil parameters. 1) The average power loss dissipated in the surrounding passive coil was significantly reduced by 85%, 2) the cuts largely reduced the secondary field generated by the eddy currents in the passive coil, which was reduced to about 4% of that produced by the uncut coil and, 3) the performance of the energized coil with slit tracks was significantly improved. Some typical gradient coil parameters, such as the figure of merit, efficiency (η), and \eta ^2/R (where η is the efficiency and R is the resistance), were improved by 8.0%, 11.9%, and 45.7%, respectively. Conclusion and Significance: The new slit coil structure is effective in mitigating intra-coil eddy current effects, which is an important issue in the MRI-LINAC system. [ABSTRACT FROM AUTHOR]

Goal: This research introduces an original method for the design of MRI gradient coils that reduces secondary field effects created by eddy current coupling. The method is able to deal with asymmetric coils and provides a new way to ensure a reduction in the magnitude of the eddy current induced fields. Methods: New constraints are introduced at the surface of passive objects to bind the normal field component below a given value. This value is determined by first treating the passive surface as an active surface, and then, calculating the ideal stream function on that surface to produce the desired secondary field. Two coils were designed, one to image the knee and the other to image the head and neck. Results: The secondary field was analyzed using linear regression and was found to improve the secondary field from 10.41 to 0.498 mT/m and from 7.84 to 0.286 mT/m in the examples used. The power loss in the passive structure also decreased to below 1% of the original value using the new method. Conclusion: The method shows the ability to constrain the field to values below the minimum seen under the traditional approaches. Significance: This will allow the design of asymmetric systems with highly linear, reduced magnitude of secondary fields and may lead to better image quality. [ABSTRACT FROM AUTHOR]

The structure of a district heating network lends itself to interactions among the grounding system of the generating plant, and those of the users, with the possibility that hazardous-induced voltages may occur on the latter. Hazards are possible due to the bonding of the heating system pipes to customer’s grounding systems, as well as to possible high values of fault currents. These electrical safety issues due to grounding electrode interactions have been so far poorly treated in technical literature. District heating pipes are generally dielectrically separated in segments by means of insulating joints. A deeper analysis of such joints shows that the hot water circulating in the pipes may bypass their insulation, rendering the effectiveness of the dielectric separation strongly dependent on the joint geometry, and on the water electrical conductivity. The authors propose possible schemes for the hot water pipe connections, and discuss their efficiency based upon the electrical configuration of the generation plant. An experimental verification procedure to assess the electrical safety of the district heating system is also proposed. [ABSTRACT FROM PUBLISHER]

This paper presents the results of field measurements of touch voltages occurring in buildings under ground-fault conditions, as well as resistance-to-ground of edifices of different nature (i.e., masonry, reinforced concrete, etc.). The goal of this experimental study was to confirm that ground-fault potential profiles and touch voltages in buildings do depend on the make-up of the structure, the floor material, the configuration and location of the grounding electrodes with respect to the point of touch, and the presence of metalwork (e.g., metal pipes) bonded to the ground system. The results of the above measurements, involving buildings of different construction type, are herein presented and discussed, and were obtained following the analytical models illustrated in Part I of this paper. [ABSTRACT FROM AUTHOR]

In several electromagnetic applications, field quantities are confined in layers that are thin with respect to other geometrical dimensions. The numerical solution of these phenomena has led to the development of special formulations. Among these, the surface impedance boundary conditions (SIBCs) have been extensively investigated in the past decades, often coupling them to other techniques for the analysis of volumes, such as the finite-element or boundary element methods. In this paper, the SIBCs are presented by the light of finite formulation and extended to include the considered magnetic nonlinearity. [ABSTRACT FROM AUTHOR]

This paper describes the coupled electromagnetic–thermal analysis of gradient coils for magnetic resonance imaging. This application deserves special attention because the eddy-current analysis of gradient coils is usually performed using filamentary and shell elements, while thermal analysis requires volume elements. This paper aims to present a seamless method to couple the mixed-element discretizations (1D, 2D, and 3D) and to project the outputs of eddy currents simulation into the corresponding thermal sources. Special attention is devoted to the management of closed domains within the integral shell element formulation. [ABSTRACT FROM AUTHOR]

This paper describes a simplified but effective methodology for the assessment of the human exposure to the magnetic field generated by resistance spot welding guns. The procedure makes it possible to compute the induced electric field in time domain as required by the standardized methodology for the assessment of pulsed magnetic fields (i.e., the weighted peak method). In this paper, we show that the proposed procedure provides results in accordance with a rigorous approach, allowing a huge reduction in the computational burden and, consequently, a significant speedup. [ABSTRACT FROM AUTHOR]

Aeronautical ground lighting (AGL) systems have been developed to deliver warnings and status indications to pilots and maneuvering area vehicle drivers on runways. Their role in preventing the hazard of runway incursions, present in the aviation industry, is therefore crucial. AGL systems basically consist of a primary series lighting circuit, which is supplied at constant current and high voltage (e.g., 5 kV), and AGL transformers supplying ground lights at their secondary sides. Protection of persons against electric shock in AGL systems cannot be conveyed by disconnection of supply as ground faults would cause the out-of-service of the lighting system, thereby compromising the safety of aerodromes; alternative protective measures are therefore employed. In this paper, the authors examine the electrical safety issues present during maintenance of AGL systems, often performed live in order to guarantee the continuity of the service. Experimental measurements on AGL isolating transformers have been also reported in this paper, and possible solutions to improve the electrical safety of operators are proposed. [ABSTRACT FROM AUTHOR]

The purpose of this paper is to analyze the main techniques for magnetic field mitigation at power frequency and assess their effectiveness presenting two real applications used as case studies. Some mitigation techniques presented in the literature are reviewed and discussed. The result of the preliminary numerical design is compared with results of measurements on real installations, showing that the available methods are mature instruments for the design of mitigation measures. [ABSTRACT FROM AUTHOR]