Use Of Conductors Research Articles

PRINCIPLES OF THE CHOICE OF THE COMBINED LIGHTNING PROTECTION FOR COMPOSITE MATERIALS OF DIELECTRIC POLYMERS

General approaches to solving the problem of lightning protection of composite materials are considered. In particular, the use of dielectric composites, which are radio transparent, requires the organization of their reliable lightning protection, which involves the use of conductors. Thus, the development of segment tires creates the prerequisites for realizing the advantages of knitted combined weaves, including metal threads, and requires further research.

Uni-layer magnets: a new concept for LTS and HTS based superconducting magnets

A novel geometrical configuration to form a magnetic field perpendicular to an aperture, created by an asymmetric current distribution, within a single layer, and using a continuous ideal current line, named the uni-layer (UL) magnet, is here presented. The idea is compared to existing concepts in superconducting magnets, namely, the sector magnet, stress managed and canted . The UL magnet allows for a design with a continuous unit length (no layer jump), and an increased minimum bending radius of the conductor in relation to traditional and canted designs. The specific characteristics of the UL design are especially advantageous for strain-sensitive and prone to winding degradation high-temperature superconductors, in very high field accelerator magnet applications, in which, high efficiency in the use of conductor, and a small aperture are required. The advantages with regard to the design and fabrication of UL magnets in relation to other concepts are also discussed.

3D Conceptual Design of R2D2, the Research Racetrack Dipole Demonstrator

R2D2, the Research Racetrack Dipole Demonstrator, is a short model being developed within a collaboration between CEA Paris-Saclay and CERN. The goal of the program is to develop key technologies for future high field 16 T Nb3Sn magnets for particle colliders. In the particular case of block-coil designs, two different cable grades are wound in the same coil layer, in order to maximize the current density, therefore to minimize the size of the magnet and the use of superconductor. One of the most challenging technologies with this grading concept, is the connection between two cables grades. CEA Paris-Saclay has proposed a concept of external joints, for which the cable exits are guided outside of the coil to perform the connections between the cable grades. The R2D2 project is aimed at demonstrating this technology in a representative demonstrator magnet, while simplifying and reducing the risks when possible, as an intermediate step towards 16 T magnets. In particular, the magnet is composed of single-layer racetrack coils, mainly to reduce the use of conductor and simplify some fabrication steps. However, the complexity inherent to the external joints requires a special focus in the design of the coil ends. To do so, the design of the magnet has been performed using a combination of CAD (Computer Aided Design), magnetic and mechanical 3D FEM (Finite-Elements Models). This paper will explain the design choices leading to a safe operation of the magnet in terms of peak fields and peak stresses.

Utilising angle-dependent critical current data in the electromagnetic modelling of HTS coils

A detailed methodology is presented for modelling the electromagnetic characteristics of HTS coils using angle-dependent critical current data obtained from experimental measurements of real wire samples. The results of such an analysis are contrasted with those obtained using more prevalent approaches such as a global minimum critical current method or an elliptical field magnitude-dependent functional approximation. Several interesting design consequences of significance to real-world devices that emerge only when the full anisotropy of real wires is taken into account are outlined and discussed. These include the beneficial impact on various performance metrics of the adoption of mixed conductor windings, the importance of coil orientation in optimising device performance, and the potential opportunity to derive a specific design benefit from the targeted use of conductors possessing inclined planarity.

АНАЛІЗ РЕЖИМУ РОБОТИ ЕЛЕКТРИЧНОЇ МЕРЕЖІ З РОЗРОБКОЮ ЗАХОДІВ ПО КОМПЕНСАЦІЇ РЕАКТИВНОЇ ПОТУЖНОСТІ

The article identifies the main measures for energy saving, among which the need to develop and implement methods and devices for reactive power compensation. It was noted that the sign of energy systems of industrial enterprises is irrational management of reactive power flows, the presence of a wide range of harmonic oscillations in the network, violation of temperature modes of individual components of electrical equipment, which leads to reduced equipment life, increased costs. The main reasons for the low value of the power factor in energyintensive industries are the presence and use in technological processes of a large number of induction motors, the power factor of which according to passport data is 0.8 under nominal operating conditions. It is noted that in practice there are often cases when the engines run in modes other than nominal - they are underloaded or overloaded, there are frequent starts of engines under load and their long operation at idle. These modes of operation of induction motors are characterized by an increased level of reactive power. The low value of the power factor leads to increased losses in the conductors, which are directly proportional to the "square" of reactive power, which requires the use of conductors of increased cross-sectional area. The paper proposed design solutions for energy saving in existing technological schemes of power supply: by analyzing the existing situation and calculating the real value of the power factor were calculated and selected reactive power compensation units.

Plasmonic infrared-laser attenuator

We describe two designs for a variable attenuator of infrared laser radiation. The principle is based on the excitation of surface plasmon polaritons with prism couplers on suitable conductors. Practical considerations dictate the use of conductors with infrared plasma frequency. An intensity variation of more than nine-orders is theoretically demonstrated. Both designs involve mechanical displacements of optical elements by less than several microns, which in principle might be much faster than current art for variable attenuators of IR laser beams. One design provides fine control at high attenuation. Experimental demonstrations support the predicted function.

Heat transfer characteristics of thermal energy storage for PCM (phase change material) melting in horizontal tube: Numerical and experimental investigations

This paper focuses on the experimental and numerical study of the storage and release of thermal heat during melting and solidification of PCM (phase change material). Heat transfer enhancement techniques such as the use of conductors like graphite and metal tubes have been proven to be effective. The material used for thermal energy storage systems is a composite based on epoxy resin loaded with metal hollow tubes filled with paraffin wax. Differential Scanning Calorimetry has been used for measurement of melting enthalpy and determination of heat capacity. The thermophysical properties of the prepared composite phase change material have been characterized using a new transient hot plate apparatus. The results have shown that most important thermal properties of these composites at the solid and liquid states are the ‘‘apparent’’ thermal conductivity, the heat storage capacity and the latent heat of fusion. These experimental results have been simulated using numerical Comsol® Multiphysics 4.3 based models with success. The results of the experimental investigation are compared favorably with the numerical results and thus serve to validate the numerical approach.

Experimental investigation of dynamic melting in a tube-in-tank PCM system

Considerable research has been conducted on heat transfer enhancement of phase change materials (PCMs) in thermal energy storage systems. Heat transfer enhancement techniques such as the use of conductors like graphite, carbon fibre and carbon brushes have been proven to be effective. Shell and tube heat exchangers which utilise many tubes in the PCM have also shown to have good heat transfer performance. Fins embedded on tubes are also effective and very popular due to its simplicity. In this paper, a new concept of a heat transfer enhancement technique for a tube-in-tank phase change thermal energy storage system has been investigated, dynamic melting. This technique is used to improve the heat transfer during the melting process. It was found from experiments that dynamic melting was more effective than those without dynamic melting. The time taken to complete the phase change process was also found to be shorter when dynamic melting was utilised. It can be concluded from experiments that dynamic melting is an effective technique for enhancing heat transfer.

Dispersion of an open thin helix

The dispersion equation for the fundamental mode of a helical slowwave system is obtained and numerically solved with the use of the periodic Green's function represented in cylindrical coordinates and the method of the linear integral equation for the helix axial current in the thinc onductor approximation. A method is proposed for taking into account a helix winded with the use of conductors with finite cross sections.

Benjamin Franklin in Europe: electrician, academician, politician

Le canard est une trouvaille de Franklin, qui a invente le paratonnerre, le canard, et la republique. Balzac, in Alfred Owen Aldridge, Franklin and his French contemporaries (New York University Press, 1957), p. 95.I am pleased and honoured to be here tonight as the Royal Society's Wilkins

Characterising borehole radio antenna performance using finite-difference time-domain modelling

Research Article| December 01, 2006 Characterising borehole radio antenna performance using finite-difference time-domain modelling Declan Vogt; Declan Vogt CSIR Division of Mining Technology, PO Box 91230, Auckland Park, 2006, South Africa e-mail: dvogt@csir.co.za Search for other works by this author on: GSW Google Scholar Andy Marvin Andy Marvin Department of Electronics, University of York, Heslington, York, YO10 5DD, United Kingdom e-mail: acm@ohm.york.ac.uk Search for other works by this author on: GSW Google Scholar Author and Article Information Declan Vogt CSIR Division of Mining Technology, PO Box 91230, Auckland Park, 2006, South Africa e-mail: dvogt@csir.co.za Andy Marvin Department of Electronics, University of York, Heslington, York, YO10 5DD, United Kingdom e-mail: acm@ohm.york.ac.uk Publisher: Geological Society of South Africa First Online: 09 Mar 2017 Online ISSN: 1996-8590 Print ISSN: 1012-0750 © 2006 Geological Society of South Africa South African Journal of Geology (2006) 109 (4): 561–570. https://doi.org/10.2113/gssajg.109.4.561 Article history First Online: 09 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Declan Vogt, Andy Marvin; Characterising borehole radio antenna performance using finite-difference time-domain modelling. South African Journal of Geology 2006;; 109 (4): 561–570. doi: https://doi.org/10.2113/gssajg.109.4.561 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietySouth African Journal of Geology Search Advanced Search Abstract Radio Tomography (RT) has proven itself as an imaging tool for base metal orebody delineation. To date, theoretical considerations of the imaging technique and inversion algorithms have concentrated on the propagation of energy from the transmit antenna to the receive antenna, while ignoring the antennas themselves.The Finite-Difference Time-Domain technique for modelling antennas has been extended to efficiently model antennas embedded in arbitrary media such as rock. The model is set up with body-of-rotation symmetry to produce models that have three dimensional accuracy, while only having two dimensional computational cost. Wire dipole antennas are efficiently modelled by the addition of a subcell extension for a thin wire coated with a thin layer of insulation.The extended code is used, both to aid in the design of an improved antenna, and to investigate how the performance of the antenna affects the imaging of RT data in particular circumstances. A completely insulated antenna is preferred because its performance is more independent of the surrounding rock. The numerical model aids in the design of an improved antenna, with the optimum combination of performance features in a physically realizable antenna. If the electronics package is placed at the end of the dipole, the electronics package can be housed in a bare metal pressure casing without significantly affecting antenna performance as a function of rock type.The model also shows how the use of RT can be influenced by the geometry of the system and particularly by the use of conductors to suspend the RT antenna: wire cable support is not recommended until full waveform inversion techniques can take into account the presence of the wire. Antenna arrays appear to be viable, but if antennas without insulation are used, the spacing between the antennas should be at least as great as the length of each antenna. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

Key engineering features of the ITER-FEAT magnet system and implications for the R&D programme

The magnet design of the new ITER-FEAT machine comprises 18 toroidal field (TF) coils, a central solenoid (CS), 6 poloidal field coils and correction coils. A key driver of this new design is the requirement to generate and control plasmas with a relatively high elongation (κ95 = 1.7) and a relatively high triangularity (δ95 = 0.35). This has led to a design where the CS is vertically segmented and self-standing and the TF coils are wedged along their inboard legs. Another important design driver is the requirement to achieve a high operational reliability of the magnets, and this has resulted in several unconventional designs, and in particular the use of conductors supported in radial plates for the winding pack of the TF coils. A key mechanical issue is the cyclic loading of the TF coil cases due to the out-of-plane loads which result from the interaction of the TF coil current and the poloidal field. These loads are resisted by a combination of shear keys and `pre-compression' rings able to provide a centripetal preload at assembly. The fatigue life of the CS conductor jacket is another issue, as it determines the CS performance in terms of the flux generation. Two jacket materials and designs are under study. Since 1993, the ITER magnet R&D programme has been focused on the manufacture and testing of a CS and a TF model coil. During its testing, the CS model coil has successfully achieved all its performance targets in DC and AC operations. The manufacture of the TF model coil is complete. The manufacture of segments of the full scale TF coil case is another important and successful part of this programme and is near completion. New R&D effort is now being initiated to cover specific aspects of the ITER-FEAT design.

Development of 3 T class Bi-2212 insert coils for high field NMR

Based on a successful 1 T Class PIT insert coil, the authors are now pursuing a 3 T Class insert coil. This paper describes the design and the latest conductor and coil test results, as well as supporting experiments. The final product is envisioned to contain 3 concentric sections, requiring over one kilometer of conductor. This will be tested in a 20 T large bore resistive magnet at the NHMFL. Experimental work focuses on the use of conductor with a silver-alloy matrix in the outer sections, that are subject to the largest stresses when operated in a background field. Results from heat treatment optimization for wound coils, mechanical test of conductors and coil design studies are reported.

A Discussion on recent advances in heavy electrical plant - Underground power cables

Up to the present, effectively all underground power transmission needs have been satisfied by the use of conductors insulated with impregnated paper. In particular, in recent years, the oil-filled cable system using cellulose paper impregnated with oil under pressure has been further developed to meet all immediate and near future needs for higher voltage and higher current power transmission underground. With modem materials and technology, are there more economical solutions and can the needs of the longer future term be met? The basic electrical, thermal, mechanical and reliability constraints which are exerted upon the design of supertension underground power cable systems are considered. The limitations upon further development of the oil-filled cable system are identified. Also, indications are given of the potentials of new insulating materials and novel constructions of cable to provide more economical solutions and greater power transmission capabilities.

The Design Problems of a Megabit Storage Matrix for Use in a High-Speed Computer

An examination of the properties of a pulse transmission matrix for a storage system is given in detail. An attempt is made to arrive at design criteria for a practical system. It appears that microstrip techniques afford an economic approach to the problem and that technically, impedances of the order of 50 ohms will present optimum over-all performance. Use of conductors of about 1 mm in width and electroformed earth shields separated by about 2 mm, will result in an access time less than 6 m? sec and a total physical size of less than a meter cube.