Arrangement Of Wires Research Articles

Design and Evaluation of EM Shielding Materials Consisting Metal Wire Arrangement Structures

Design and Evaluation of EM Shielding Materials Consisting Metal Wire Arrangement Structures

The magnetic field of a three-phase power line with an ordinary and triangular arrangement of wires

Power lines are sources of magnetic fields, which requires attention to ensure safety for people and to consider electromagnetic compatibility. In this article the nondimensional form expressions for calculation of magnetic field strength of a three-phase line with an ordinary and triangular arrangement of wires were obtained what makes it possible to calculate the necessary distance to the core of the line if the maximum permissible level of magnetic field strength is provided. The approximate expression of magnetic field strength at large distance from the line was considered. It is valid with the measurement accuracy less than 1%, which shows the proportion between magnetic field strength and distances between wires and inverse proportion of square distance to the wire core. It was determined that the triangular arrangement of three-phase line wires has lower magnetic field strength than the arrangement of wires in row due to more compact arrangement of wires.

Experimental study on the heat transfer performance of ultra-thin flattened heat pipe with hybrid spiral woven mesh wick structure

In this work, eight different spiral woven mesh (SWM) structures, namely, SA, SB, SC, SD, SE, SF, SG and SH, were designed to investigate the effect of the SWM weaving method on the heat transfer performance of ultra-thin heat pipes (UTHPs). The SA and SH were SWMs, severed as the control group, and they were woven using only 0.05 and 0.04 mm diameter copper wires, respectively. The other six types were hybrid SWM (HSWM) structures that were woven from the two diameters copper wires. The thermal performance of the UTHPs with different SWM/HSWM wick structures was experimentally investigated. The results indicated that the number and distribution of different-diameter copper wires in every strand of HSWM determine the pore size and total pore volume inside the wick. The staggered arrangement of different-diameter copper wires in the HSWM is conducive to the formation of more multisize pores in the wick, thereby improving its comprehensive hydraulic performance. Compared with the SA and SH UTHPs, the maximum heat transport capacity of the SB and SF UTHPs increased by 33.33–53.85% and the total thermal resistance decreased by 27.53–42.92%, significantly improving the heat transfer performance of UTHP by using the appropriate HSWM wicks.

Interactions of magnetized plasma flows in pulsed-power driven experiments

A supersonic flow of magnetized plasma is produced by the application of a 1 MA-peak, 500 ns current pulse to a cylindrical arrangement of parallel wires, known as an inverse wire array. The plasma flow is produced by the J × B acceleration of the ablated wire material, and a magnetic field of several Tesla is embedded at source by the driving current. This setup has been used for a variety of experiments investigating the interactions of magnetized plasma flows. In experiments designed to investigate magnetic reconnection, the collision of counter-streaming flows, carrying oppositely directed magnetic fields, leads to the formation of a reconnection layer in which we observe ions reaching temperatures much greater than predicted by classical heating mechanisms. The breakup of this layer under the plasmoid instability is dependent on the properties of the inflowing plasma, which can be controlled by the choice of the wire array material. In other experiments, magnetized shocks were formed by placing obstacles in the path of the magnetized plasma flow. The pile-up of magnetic flux in front of a conducting obstacle produces a magnetic precursor acting on upstream electrons at the distance of the ion inertial length. This precursor subsequently develops into a steep density transition via ion-electron fluid decoupling. Obstacles which possess a strong private magnetic field affect the upstream flow over a much greater distance, providing an extended bow shock structure. In the region surrounding the obstacle the magnetic pressure holds off the flow, forming a void of plasma material, analogous to the magnetopause around planetary bodies with self-generated magnetic fields.

Failure characteristics of UHPFRC panels subjected to projectile impact

This study investigates the failure characteristics of ultra-high performance fiber-reinforced concrete (UHPFRC) panels subjected to a steel projectile impact. Impact tests for 60–120-mm-thick UHPFRC panels were conducted to examine the failure state and impact resistant performance of the panels by using an 8.3-kg-mass projectile with a diameter of 90 mm at a velocity approximately corresponding to 42 m/s. Experimental parameters included the arrangement of pre-stressing steel wires and enforcement of pre-stress. Although the effect of arranging the pre-stressing steel wires on the damage restraint of UHPFRC panels was observed, the enforcement of pre-stress was not significantly effective in mitigating the damage. The impact response characteristics of UHPFRC panels were investigated by comparison between the impact force, reaction force, and strain response.

Resin-Air Two-Phase Flow in Injection Molding Processes: An Application to Polymeric Composite Containing Embedded Metal Wires

The development of materials with specific properties is a relevant engineering topic. The composite materials, hybrid of metal structures embedded in polymer matrices, are intensively used in mechanical systems in order to obtain materials with high resistance associated to low weight. To fabricate these materials, it is necessary to inject the polymeric resin in a liquid state in mold cavity, which characterizes a multiphase flow as the air present in the mold is repelled by strategically projected outlets. In this sense, a correct knowledge of the flow mechanisms existing in the molding process is necessary to guide the parts manufacture. Through the Ansys FLUENT® software, this work performs a mathematical modeling of the resin transient flow inside a mold where metal wires are located and presents a numerical solution that describes, through calculations of volumetric fractions, velocity and pressure fields, and the fluid dynamic aspects that characterize the liquid molding process. It has been observed that the pressure required to maintain the constant flow at the mold inlet is increased until 80s of the process, when the steady state condition is achieved, that there is a greater resistance to mold filling in the side regions close to the mold wall due to the metal wires arrangement and that the air removal velocity that occurs due to resin injection becomes very low from the moment that resin reaches the mold outlets.

Analysis of arc stability and bead forming with high-speed TW-GIA welding

Triple-wire gas indirect arc (TW-GIA) welding is a new type of welding method. In the TW-GIA welding process, the workpiece is not connected to the power source, and the arc is built between the three wires. In this essay, the arc stability and bead forming of the high-speed TW-GIA welding are studied under a new wire arrangement. Results show that with the increasing of the welding currents, the range of voltage and current fluctuations are reduced during the welding process, and the arc stability is improved. The reason is that increasing current can stabilize the droplet transfer. Since the arc is built between the welding wires, the influence of welding speed on the arc stability of TW-GIA welding is limited. Compared with traditional gas metal arc welding, TW-GIA welding has the characteristics of high deposition rate and low dilution rate, which is helpful for increasing welding speed. The welding speed of 2 mm-thickness steel plate can reach 2.8 m/min by using TW-GIA welding.

Microwave programmable response of Co-based microwire polymer composites through wire microstructure and arrangement optimization

Traditional approaches to realize microwave tunability in microwire polymer composites which mainly rely on topological factors, magnetic field/stress stimuli, and hybridization are burdensome and restricted to rather narrow band frequencies. This work presents a facile strategy based on a single component tunable medium to program the transmission response over wide frequency bands. Structural modification of one type of microwire through suitable current annealing and arrangement of the annealed wires in multiple combinations were sufficient to distinctly red-shift the transmission dip frequency of the composites. Such one wire control-strategy endorsed a programmable multivariable system grounded on the variations in both the overall array conductivity or “effective” area determined by the wires arrangement and the relaxation time dictated by the annealing degree of microwires. These results can be used to prescribe transmission frequency bands of desired features via diverse microwire arrays and microwave performance from a single component to composite system design.

Dosimetric issues with simplified homogeneous body models in low frequency magnetic field exposure assessment

A simplified procedure, using circular disk models with homogeneous electric conductivity as representations for different body parts, has been proposed recently by product standard IEC 62822-3 for the assessment of magnetic field exposure in proximity to current-carrying conductors of welding equipment. Based on such simplified models, worst case coupling coefficients CCEi(I), i.e. maximum induced electric field strength, normalised for current and frequency, for body parts at different distances d to straight single and double wire arrangements, as well as rectangular loop-shaped current paths are tabulated in the standard. In this work we compared CCEi(I) values obtained by numerical computations with detailed anatomical models of the hand/forearm with the corresponding values given in IEC 62822-3 for current-carrying single wire conductors along the forearm at distances d = 30, 50 and 100 mm, respectively. Our results clearly indicated that the CCEi(I) given in the standard may substantially underestimate the actual exposure. Using average values for tissue conductivities the observed extent of underestimation was up to 8.9 dB (factor 2.79) and may be even higher for worst case combinations of tissue conductivities. The reasons for this substantial underestimation are the oversimplified geometry, i.e. the circular disk does not reflect anatomical constrictions of the induction area present in realistic hand/forearm geometries, as well as the missing conductivity contrast between different tissues in the homogeneous disk models. Results of exposure assessment and corresponding minimum distances to components of welding equipment obtained by the simplified disk model approach suggested by IEC 62822-3 should therefore be considered with caution.

A triple-wire indirect arc welding method with high melting efficiency of base metal

This study presents a modified triple-wire indirect arc welding method to improve melting efficiency of the base metal. To achieve this, a mirror-symmetrical wire arrangement was adopted because of small arc distribution space and the electrode polarity is changed different from the previous triple-wire indirect arc welding method. The arc shape is observed with the novel wire arrangement, and the bead-on-plate welding experiments arecarried out and the melting efficiency of the base metal was calculated. Results reveal that the adopting welding wire polarity of the main wire and the side wire respectively acting as anode and cathode can superimpose the two indirect arcs into a single indirect arc which increases the arc energy concentration. The main reason is that the indirect arcs deflect to the main wire and the arc voltage is improved. As a result, the penetration, the melting area and the melting efficiency of the base metal are improved to varying degrees with increasing current. For instance, at the current is 400A, they were increased to 2 times, 3 times and 2.55 times, respectively. Meanwhile, a single pass butt joint of 10mm plates by the modified triple-wire indirect arc welding with low energy consumption and high efficiency is successfully accomplished.

APPLICATION FEATURES OF POLY-CIRCUIT OVERHEAD TRANSMISSION LINES

It was shown the necessity to improve the operational reliability of overhead transmission lines as one of the main parts of the electric power transmission system. Question considered the feasibility of using poly-circuit overhead transmission lines. Analyzed the regulatory framework governing the design and construction of poly-circuit overhead transmission lines, as well as the calculation of electric and magnetic fields. It was shown that the regulatory framework governing nonrelevant to the possibility of using poly-circuit overhead transmission lines with a vertical arrangement of the phases wires. It was substantiated the advisability of additional in-depth studies of the electric and magnetic fields distribution of poly-circuit overhead transmission lines of various designs and voltage levels. It was presented the sequence of modeling the distribution of the electric field for overhead transmission line both traditional and poly-circuit design of 110 kV. It was presented the simulation results that confirm the accounting feasibility the design of transmission towers and the spatial arrangement of wires during the calculating of electric field strength. It was shown that simulation results using will significantly improve the reliability and operational safety of poly-circuit overhead transmission lines.

Semi-exact solution for nonlinear dynamic analysis of graded carbon nanotube-reinforced beam with graded shape memory wires

In this study, the nonlinear dynamical response of a graded carbon nanotube-reinforced beam with graded shape memory wire has been investigated regarding the instantaneous variations of martensite volume fraction and therefore material nonlinearity along the beam. The boundary conditions of the beam are considered as the clamped-clamped. Carbon nanotubes and shape memory wires have been arranged in various distributions of UD, and FG – A along the thickness of the beam. The governing differential equation of the beam is obtained by the use of Brinson’s relation to describe the behavior of the shape memory wire, considering Von Karman nonlinear strain and utilizing Hamilton's principle. The obtained nonlinear equation is solved using the semi-exact solution. For this purpose, Galerkin’s method was first used to isolate the spatial derivatives from the time derivatives and then the obtained equation was solved using Runge-Kutta method. A comparative study has been conducted between the present study and the reference paper to confirm the presented model. This comparison study shows an appropriate agreement between the results of this research and the previous studies. In this research, the influence of the certain parameters such as the considering the nonlinear effects, the volume fraction of carbon nanotube, the type of carbon nanotube distribution, the volume fraction of shape memory wire, and the type of its arrangement on the vibrational behavior of the beam and its loss factor is investigated. Some results show that, in case of the vibration of the beam by the initial excitement, the higher density of carbon nanotubes in the mid-layers and the higher density of the shape memory wires in the outer layers of the beam lead to the higher amount of loss factor. Also, the percentage of the reduction in the loss factor which occurs due to the reduction of the volume fraction of the shape memory wire is almost the same in the beams with different distribution and arrangement of carbon nanotubes and shape memory wire.

Synchrotron based X-ray radiography of convergent shock waves driven by underwater electrical explosion of a cylindrical wire array

We present X-ray radiography images showing the propagation of shock waves generated by electrical explosion of a cylindrical arrangement of wires in water driven by pulsed power. In previous experiments [S. N. Bland et al., Phys. Plasmas 24, 082702 (2017)], the merger of shock waves from adjacent wires has produced a highly symmetrical, cylindrical shock wave converging on the axis, where it is expected to produce a high density, strongly coupled plasma ideal for warm dense matter research. However, diagnostic limitations have meant that much of the dynamics of the system has been inferred from the position of the front of the cylindrical shock and timing/spectra of light emitted from the axis. Here, we present a synchrotron-based radiography of such experiments—providing direct quantitative measurements on the formation of the convergent shock wave, the increased density of water on the axis caused by its arrival, and its “bounce” after arrival on the axis. The obtained images are compared with two-dimensional hydrodynamic simulations, which reproduce the observed dynamics with a satisfactory agreement in density values.

Stator Design Aspects for Permanent Magnet Superconducting Wind Power Generators

This paper presents an electromagnetic design of a permanent magnet superconducting wind power generator with different stator teeth structures and armature winding arrangements. The main contribution of this paper is that a novel stator configuration is proposed, which is beneficial for superconducting machines. The topology of tapering poles makes it possible for the machine to carry larger current without severe magnetic saturation in the stator teeth. Meantime, the distributed arrangement of wires in the stator slot can reduce the ac loss in the same output power condition. Finite element analysis with commercial software is used to support these results.

General Analytical Model for the Thermal Resistance of Windings Made of Solid or Litz Wire

In this paper, an analytical method to model the thermal resistance of windings made either of solid or litz wire is presented and validated by measurements. In addition, an extended numerical approach for litz wire windings, which also considers the twist pitch, is shown. With the presented model, it is possible to describe the thermal resistance of arbitrary wire arrangements. This approach can be used in straightforward thermal designs of magnetic devices, or it can be integrated in optimization procedures to improve the thermal designs of magnetic components. The analytical models are verified by measurements with nonpotted and epoxy-potted solid wire test setups and test setups for litz wire, which all show a good matching between the calculated and measured values. Besides the models for the thermal resistance between the winding layers, a method to simplify the thermal network of multilayer windings is presented. Finally, a thermal equivalent circuit of a test transformer has been calculated, which shows a good match between the measured and the predicted temperature distribution.

МОДЕЛИРОВАНИЕ КОМПАКТНЫХ ЛИНИЙ ЭЛЕКТРОПЕРЕДАЧИ С ТРЕУГОЛЬНЫМ РАСПОЛОЖЕНИЕМ ПРОВОДОВ

Development of methods and simulars of compact lines of an electricity transmission
 of the increased capacity. Methods of definition of the modes of electrical power systems (EPS) on the
 basis of phase coordinates which basis models of elements in the form of trellised equivalent circuits
 with full-coherent topology are were applied. These models and methods are realized in the program
 Fazonord-APC complex providing modeling of the EPS stationary modes and also definition of tensions of the electromagnetic field which is created by power lines of various design. Results of modeling of the modes and electromagnetic fields on routes of the compact power line (CPL) of an electricity transmission of 220 kV with a triangular arrangement of wires are presented. For comparison similar calculations for a standard power line (SPL) of 220 kV of a standard design are executed.

Control of boundary layer by ionic wind for heat transfer

In this study, local convection heat transfer technology was investigated using ionic wind. The characteristics of ionic wind using wire and plate electrodes are studied by experiment and numerical method. A particle image velocimetry (PIV) test was conducted in a wind tunnel to observe the flow behavior by the ionic wind on the heated surface. A new boundary layer was formed on the heated surface which was controlled by the ionic wind, regardless of the Reynolds number of bulk flow. The surface averaged heat transfer coefficient with the ionic wind increased by 11% at low Reynolds number (100–200) and decreased by 19% at high Reynolds number (2500–3500). It was also found that the zigzag type of wire arrangement enhanced the heat transfer coefficient by 40% compared with the single wire. It is thus concluded that ionic wind can be used for enhancing the convection heat transfer rate or insulating the local surface according to its operating condition.

The Backbone: Construction of a Regional Electricity Grid in the Arabian Peninsula

ABSTRACTThis article studies the production of a power grid across six Gulf Cooperation Council (GCC) countries, known as ‘the backbone,’ which has been conceptualized as an answer to power outages. First it analyzes how experts working with and around the GCC Interconnection Authority (GCCIA) advance claims to a regional territorial imagination. Second, it shows that the construction of the grid not only indicates a shift in the material arrangement of wires and substations, but also necessitates new understandings of transparency and a new formula for the electricity price, facilitating the cutting of government subsidies along with additional price increases. Third, it interrogates how electricity is consumed in the region. Policy-makers expected that electricity price increases would lead to lower rates of consumption. Yet after price hikes were instituted, analysts reported how they had no impact. Users behaved in ways that the grid’s engineers did not anticipate. Overall the article shows how various actors conduct ‘boundary work,’ that is, how they set limits between the political, the financial and the technical while producing the backbone. The article explores how this boundary work helps stabilize a particular sociotechnical imaginary of energy security in the GCC, masking anxieties associated with a future beyond oil.

Investigation of cable bolts for stress corrosion cracking failure

Premature failure of cable bolts due to stress corrosion cracking (SCC) in mining and civil industries is a worldwide problem with limited cost-effective solutions. A load frame capable of applying tensile loads was designed and constructed to simulate and examine SCC of full-size cable bolts (up to 2.4 m in length) under simulated in-situ conditions. The tension loading apparatus was used to conduct periodically increasing strain rate (PISR) tests on cable bolts in simulated underground environments. The PISR test was appropriate and reliable for examining SCC susceptibility of TG and Superstrand cable bolts including the effects of wire arrangement, galvanisation and indentation. Overall, TG cable bolts were more susceptible to SCC than Superstrand cable bolts. In each type of cable bolt, the one with plain wires was approximately 30% more resilient to SCC in terms of time to failure than the one with indented wires. Galvanising was not able to prevent SCC, however it considerably delayed SCC occurrence. The results of this study provided detailed insight into SCC of different types of cable bolts and can be further used for setting up optimal support regimes in different geological and environmental conditions.

Study on wind resistance coefficient of double split wire arrangement

Shape coefficients of a single traverse and twin branch lines are examined through wind tunnel experiments and numerical simulations under different angle of attacks and wind speeds. It was found that the shape coefficient at angle of attack equaling to 0 is obviously smaller than the others. And the effects of Reynolds number are also large. The numerical results give difference between cases reaching 20 %, however, the experimental ones only 1.17 %. It is because that the initial condition of CFD is idealized but the wind tunnel experiment is closer to the reality.