Double Wire Research Articles

Gradient transition zone structure in “steel–copper” sample produced by double wire-feed electron beam additive manufacturing

This paper describes the results of an investigation into a microstructure formation on a wire-feed electron beam additive manufactured “steel–copper” bimetallic sample. The peculiarities of a gradient zone structure with a smooth change of components’ concentration are revealed. The heterogeneity of copper and steel distribution in the gradient zone is provided by copper solidification and precipitation mechanisms. Both solidification of coarse copper inclusions in the interdendrite areas or along the dendrite boundaries and precipitation of fine Cu-based particles at the cooling stage from the solid solution of Cu in γ-Fe are the main factors of structure formation during the double wire gradient zone deposition. The presence of such fine copper precipitates from the supersaturated solid solution was revealed by means of transmission electron microscopy. The shape of copper particles in the gradient zone varies from spherical to oblong and irregular. The shape of steel particles and/or grains is mainly determined by the peculiarities of the crystallization zone and is characterized by the primary crystallization of γ-iron dendrites from the liquid melt. A physical scheme describing a variation in phase composition and microstructure in gradient zone of the bimetallic specimen was proposed.

A preliminary study on the double cold wire gas metal arc welding process

The increasing demands in productivity and reliability in welding have led to the development of newer welding processes. These processes frequently have superior deposition rates; however, they might lead to a wider heat-affected zone (HAZ) which might impair their mechanical properties. Here, a promising process termed the double cold wire gas metal arc welding (DCW-GMAW) is evaluated, offering higher deposition rates via feeding two cold wires into the weld pool to improve productivity. In contrast to similar processes, the HAZ of DCW-GMAW welds are smaller than gas metal arc welding (GMAW) welds. This work reports a preliminary assessment of the feasibility of the process in terms of electrical arc characteristics and stability. High-speed video acquisition was used to analyze the metal transfer across the arc. Finally, standard metallographic techniques and Vickers hardness were used to assess the weld cross sections and microstructures. The results demonstrate the feasibility of DCW-GMAW based on the process stability at different cold wire feed rates while also offering high deposition (high productivity) of weld deposits with desirable hardness due to increased acicular ferrite content.

Nonlinear optical properties of semiconductor double quantum wires coupled to a quantum-sized metal nanoparticle

We theoretically investigate linear and nonlinear optical absorption coefficients (OACs) and refractive index changes (RICs) of two quantum wires (QWs) separated by a quantum-sized metal nanoparticle (MNP) using a density matrix method and dielectric quantum theory. The exciton-plasmon coupling and the dipole-dipole interaction (DDI) between the two QWs are taken into account. We find that the magnitudes of the linear and nonlinear OACs (RICs) from the QWs are enhanced by one order of magnitude, in contrast to the case without a MNP, due to the exciton-plasmon coupling and the DDI between the two QWs. The quantum size effect in a MNP induces a pronounced enhancement in the magnitudes of the linear and nonlinear OACs (RICs) with the increase of the MNP radius. Furthermore, the optical responses can be further strengthened via increasing the MNP radius or decreasing the radius and gap of the QWs, owing to the enhanced exciton-plasmon coupling and the DDI between the two QWs. Moreover, the magnitudes of the total OACs (RICs) are reduced by increasing the optical intensity, along with a splitting effect of the OACs under strong optical intensity. Our results provide the possibility of designing the hybrid nanostructures with large nonlinearity for applications in nano-devices such as optical switches and amplifiers.

PTCA in anomalous RCA arising from left sinus of valsalva - A case series

Background: Anomalous origin of the right coronary artery (AORCA) from the left sinus of Valsalva (LSOV) accounts for 6%–27% of all coronary anomalies. Systematic planning and selection of appropriate catheters are pertinent for successful results. On many occasions, it is not possible to selectively cannulate the vessel despite the use of multiple catheters or modified curves in them. Situation worsens in acute coronary syndrome scenario where valuable time is lost just trying to delineate the diseased coronary anatomy. Aims and Objectives: to study the guide catheter selection in cases of (Anomalous RCA) AORCA arising from left sinus of valsalva (LSOV). Materials and Methods: We encountered six cases of AORCA from left sinus of valsalva with significant coronary lesions in one year. Results: Three cases were done through transfemoral access and in three others cases the access was switched from transfemoral to right radial access. In two of these cases we adopted a double length coronary wire for performing the percutaneous transluminal coronary angioplasty (PTCA) as compared to the regular technique. Conclusion: In order for PTCA to be successful in anomalous coronary arteries, optimal guide catheter seating and catheter back up should be achieved, both of which may require modification in either the technique or change in access or alteration in the guiding catheter employed. While performing primary PCI, the operators and the ancillary staff need to be aware of this anomaly and be prepared. Exchanging guide catheter on coronary double length wire though cumbersome can ensure successful outcome. Change to right radial approach may confer an additional advantage of cannulating the vessel as the catheter gets support from the contralateral aortic wall.

Использование силового электронного ключа при борьбе с гололедом на контактной сети импульсно-резонансным методом

The possibility of technical implementation for deicing of double contact wires by pulse-resonance method using a high-power electronic switch is evaluated. For a specific double-track road section of overhead line network, the parameters of the necessary step-down transformer operating in pulse mode and providing heating of the contact wires to positive temperatures are calculated. A possible range of changes in the current density of the contact wires, controlled by the relative pulse duration, is determined.

A Double Tension Band Technique for Patellar Fractures—A New Concept

Amongst the many known techniques used for the management of fractures of the patella, the tension band wire fixation is a reliable treatment modality and has given consistently good results. In transverse patellar fractures, a combination of cerclage wiring and tension band fixation gives a good mechanical stability and an environment conducive to healing. The fracture described herein is classified as 45-C1 (based on Orthopaedic Trauma Association classification) of the right knee of a forty three years old male patient. It was fixed with three vertical 1.5 mm K wires and double cerclage wire looped proximally through the quadriceps tendon and distally through the patellar ligament in a double figure-of-eight configuration. The average follow-up period was 7 months. The Activity of Daily Living Scale (ADLS) of the Knee Outcome Survey was used to assess symptoms and functional capability of the knee. The fracture union was achieved at an average of 10 weeks. Full range of knee motion was achieved by end of the third postoperative month. No complications, such as infection and implant failure were noted. The technique aims to stress the advantage of giving a balanced fixation addressing the bony elements (the fractured ends) as well as the soft tissue (the extensor apparatus).

Magnetic nanoparticle drug targeting to patient-specific atherosclerosis: effects of magnetic field intensity and configuration

Nanoparticle-mediated drug delivery is recognized as a promising option for targeted treatment of atherosclerosis. In this paper, the Eulerian-Lagrangian technique is adopted to simulate the delivery of drug-loaded nanoparticles to patient-specific atherosclerotic plaque with the aid of an external magnetic field. Plaques and vascular walls are introduced as porous media formulated by the Darcy-Forchheimer model in this targeted transport process. The results demonstrate that the delivery efficiency of particles to atherosclerosis depends on the external magnetic field, such as configuration and intensity, in which the configuration angle of the current wire is a key factor and the double current wires have advantages over the single current wire. Meanwhile, the delivery efficiency gradually decreases as the distance between the plaque cap and the current wire increases. Further, although augmenting the current or magnetic susceptibility can generally improve the delivery efficiency of nanoparticles, this increase is not apparent when small-sized nanoparticles are employed as drug transport particles. The results obtained can potentially serve as the guideline to optimize regimens for the targeted therapy of atherosclerosis.

Open reduction and compression with double Kirschner wires for the treatment of old bony mallet finger

BackgroundThe management of old bony mallet fingers is complicated. The aim of the study is to present a new method of open reduction and compression with double Kirschner wires (K-wires) in treating old bony mallet fingers.MethodsThis was a retrospective analysis of patients with old closed bony mallet fingers treated between June 2013 and December 2016. Complications were observed. The range of motion (ROM) of the DIP joints was measured using a protractor. At the last follow-up, anteroposterior and lateral X-ray of the affected finger was performed, the flatness of the articular surface was scored, and the results were graded using Crawford’s criteria.ResultsSeventeen patients were followed up for 8 (6–19) months. The width of the avulsion fracture block accounted for 25–62% of the articular surface of the distal phalanx. Twelve (70.6%) patients had anterior dislocation of the interphalangeal joint. All patients reported healing at the fracture sites. Healing time was 7.6 ± 2.1(5–13) weeks. All patients had incision healing of I/Class A. Lateral X-ray showed 13 and four patients had excellent and good articular surface flatness, respectively. At the last follow-up, no traumatic arthritis was present. Only one patient developed mild pain after surgery (VAS score of 3). Postoperative ROM was 76.5 ± 10.6° (P = 0.0625 vs. healthy side). At the last follow-up, the angle of loss of dorsiflexion was 0–10° (P < 0.0001 vs. baseline). The flexion angle was 50–90° (P = 0.0625 vs. healthy side).ConclusionsOpen reduction and compression with double K-wires is feasible in treating old bony mallet finger.

Model of particle accumulation on matrices in transverse field pulsating high gradient magnetic separator

The static buildup model of particle on single wires (SBM-sw), illustrating the effect of these influencing parameters such as applied magnetic induction, fluid velocity and wires size on particle accumulation, plays a dominant role in instructing the design of a high gradient magnetic separation (HGMS) device. However, in a real separation chamber of HGMS filled with piles of matrices, the changes of hydrodynamic due to gap shrinkage of matrices disturb particle accumulation. When slurry within the matrix is exposed to pulsation, this disturbance is intensified. Consequently, compared to SBM-sw, the model of magnetic particle accumulation on double wires (SBM-dw) is supposed more suitable to reveal the processing of magnetic particle accumulation on matrices. In this article, SBM-sw and SBM-dw of a transverse field pulsating HGMS separator (TPHGMS) was presented based on force equilibrium. The effect of pulsating slurry, wire spacing and applied magnetic induction on particle accumulation of the TPHGMS was investigated and discussed with calculating the buildup profiles under specific parameters. Pulsating slurry directly impinges the regions of paramagnetic particle capture and leads to sharp decrease of particle buildup under high frequency. Enlarging wire spacing or decreasing pulsating frequency can weaken the impact of slurry and slow down the decrease of particle buildup. In addition, increasing applied magnetic induction within a certain range can also significantly increase particle buildup. Finally the SBM-dw model was compared with a series of experiments. Results indicated that experimental particle buildup weights agreed with the calculated particle buildup weights of SBM-dw which provides better authenticity to understand and predict the performance of the TPHGMS.

Single-Pulse Avalanche Failure Investigations of Si-SJ-mosfet and SiC-mosfet by Step-Control Infrared Thermography Method

The step-control infrared thermography method was proposed to investigate comprehensive single-pulse avalanche failure details of Si-superjunction (SJ) mosfet and SiC- mosfet . By this method, the damage location and even its shift in real time during the whole avalanche process can be observed. It is shown that, for the Si-SJ- mosfet , the avalanche damage location is extended from the cell region toward termination region with the increased avalanche time. The parasitic bipolar junction transistors at the cell corner near the termination are triggered due to the increased p-base resistances under relatively high temperature. However, for SiC- mosfet , the avalanche location is always kept within the cell region mainly due to insensitive breakdown voltage dependence on temperature. As a result, its failure site is found to locate at the source pad near the wire bond, likely due to the lattice temperature beyond the melting limit of aluminum contacts. Finally, the schemes to improve avalanche robustness, including the two different N -Epitaxy layers for Si-SJ- mosfet and the double source wire bonds for SiC- mosfet , have been proposed and verified basing on different failure mechanisms.

Effect of lay direction on the mechanical behavior of multi-strand wire ropes

The effect of lay direction of individual wires on the mechanical behavior of multi-strand wire ropes under axial loading is investigated based upon Love's thin rod theory. A typical 7 × 7 wire rope with an independent rope core is treated. Eight different lay directions of the wire rope are considered, in which the lay direction of the double helix wires is emphasized. Two theoretical models, namely the hierarchical calculation method and the direct calculation method, are used to calculate the internal forces of the rope. The numerical results based on the two models are assessed within the context of the finite element analysis of the multi-strand rope. It is highlighted that the result given by the hierarchical calculation method is closer to the FEM result. The mechanical responses on simple strand and multi-strand rope predicted by the two theoretical models are in good agreement with experimental data. The lay effect of wire rope and the effect of initial helix angle of individual wires on the internal forces of rope are analyzed in detail. It is demonstrated that the lay direction mainly affects the torque of the rope, but not the tensile force; while both the torque and the tensile force strongly depend on the initial helix angle of individual wires. It is implied that the global mechanical properties of wire rope can be adjusted with the lay direction and the helix angle of wires within the rope.

Up to 80 Gbaud DP‐16QAM operation using InP‐based high‐bandwidth coherent driver modulator

The authors obtained very good back-to-back bit error rate performance in up to 80 Gbaud DP-16QAM operation by using their coherent driver modulator of a 3-dB electro-optic bandwidth of over 50 GHz. To achieve high bandwidth and good signal integrity, they used double ultra-low loop wires between the driver IC and the modulator and a differential capacitively loaded travelling-wave RF electrode based on straight coupled coplanar waveguide with a ground-signal-signal-ground configuration for their InP modulator. As far as they know, this is the highest bandwidth and baud rate operation so far for the high-bandwidth coherent driver modulator configuration.

Double-wire tandem GMAW welding process of HSLA50 steel

Tandem welding process employs double wire feed in a single torch, providing increased deposition rate and consequent reduction in process times. However, the process complexity increases since an optimum combination of parameters is essential to avoid the occurrence of interference between both electric arcs. Such interferences may result in hindering stability of the welding process, leading to poor weld bead geometry. To address this problem, the present investigation proposes an approach to reduce the number of arc’s inconsistencies during welding of a 15-mm HSLA50 steel plate with ER70S-6 wire. Three configurations were tested considering high-current ratings in lead and trail wires: pulsed-pulsed waves (torch angle: 90°), continuous-pulsed waves (torch angle: 90°) and continuous-pulsed waves (torch angle: 80°). In the three cases, the welding arc voltage and currents were acquired, and penetration profile and the dimension of the heat affected zone (HAZ) evaluated. Microhardness testing was utilized to investigate the mechanical strength of the HAZ. The best combination of parameters was found considering the three welding conditions tested in this study, where the lead wire was parameterized in constant voltage mode and the trail wire in pulsed spray metal transfer with a torch angle of 90 ° from the workpiece. 20% higher displacement speed of the robot and no occurrence of inconsistences in the electric arcs were accomplished.

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.

One-Dimensional Double Wires and Two-Dimensional Mobile Grids: Cobalt/Bipyridine Coordination Networks at the Solid/Liquid Interface.

Various architectures have been generated and observed by STM at a solid/liquid interface resulting from an in situ chemical reaction between the bipyridine terminal groups of a ditopic ligand and Co(II) ions. Large monodomains of one-dimensional (1D) double wires are formed by Co(II)/ligand coordination, with polymer lengths as long as 150 nm. The polymers are organized as parallel wires 8 nm apart, and the voids between wires are occupied by solvent molecules. Two-dimensional (2D) grids, showing high surface mobility, coexist with the wires. The wires are formed from linear chain motifs where each cobalt center is bonded to two bipyridines. 2D grids are generated from a bifurcation node where one cobalt bonds to three bipyridines. Surface reconstruction of the grids and of the 1D wires was observed under the STM tip. As an exciting result, analysis of these movements strongly indicates surface reactions at the solid/liquid interface.

Durability and Performance of Ferrocement Infill Wall Panel

Ferrocement is composed of cement mortar reinforced with small diameter closely spaced steel wire mesh to form a thin section conforming high performance of serviceability. The present study investigates the performance of ferrocement panels focused on the mechanical properties, water absorption and durability. A series of specimens were cast with single and double mesh layers. Flexural performance was carried out following sixty days in temperature cycle and in corrosion cell. These results was compared with the controlled sample. The test results shows that the flexural strength performance was reduced by 52% and 35% for single and double layer wire mesh samples respectively followed by corrosion environment. First crack load also changed after completion of sixty temperature cycles. This load is 27.3%, 42.3% and 31.8% of failure load for controlled sample, sample in room air after every temperature cycle and samples in room air following quenching after every temperature cycle respectively for single mesh layer sample, and for double mesh layer sample these values are 38.9%, 30.1% and 17.7%. Early first crack is found for the samples following quenching and cooled in room air; however, both types of samples are in low absorption level. This data represents that double layer mesh specimen exhibits better when compared to single layer mesh specimen in strength and corrosion parameters.

Reconfigurable quantum logic gates using Rashba controlled spin polarized currents

A reconfigurable logic gate is proposed in a two-dimensional double quantum wire system with a coupling window enabled by a Rashba field. Manipulating the spin states of incoming electrons several quantum logic gates (OR, AND, XOR, CNOT) can be implemented. The logic gate functionality can be switched by tuning the Rashba parameter only. In this context, we investigate suitable configurations of the device region by embedding a quantum point contact located in the coupling region to obtain all four logic gates. The ballistic spin polarized transmission functions are calculated using an effective mass scattering formalism in the framework of a multi-channel, multi-terminal system. Owing its versatility, the proposed logic gate can be integrated in programmable architectures, able to implement both classical and quantum algorithms.

Nanowire‐based branched nanotrees prepared by flame vapor deposition system incorporated with double wire feeders

SignificanceWe developed a facile approach for fast growth of branched nanotrees in a newly designed double‐wire‐feeder incorporated flame vapor deposition system. Nuclei formation on preformed nanowires for branch growth is innovatively done by traversing horizontal wire across flame. The density of nanobranches and resultant morphology of branched nanotrees could be tuned through a precise control over wires‐feeding pattern. The entire process can be done coherently without necessity of other process involvement or any interruption. © 2019 American Institute of Chemical Engineers AIChE J, 65: 1138–1143, 2019

Meta-Surface Antenna Array Decoupling Designs for Two Linear Polarized Antennas Coupled in H-Plane and E-Plane

In this paper, meta-surface superstrates are used to decouple two linear polarized antennas coupled in H-plane and E-plane, respectively. By properly designing the geometry of the double layer short wires as the unit cell of the meta-surface, as well as the height of the meta-superstrate, two linearly polarized antennas can be decoupled in H-plane and E-plane, respectively. Both the antenna pairs coupled in E- and H-planes with and without meta-surfaces are fabricated and measured. The results demonstrate that the antennas with the meta-surface superstrate are able to operate in the band of 3.3–3.7 GHz with reflection better than −15 dB and the isolation can be improved from 10 to 25 dB in the H-plane case and can be improved from 15 to 30 dB in the E-plane case. Such decoupling method can be applied extensively in 5G base stations where size constraints are becoming stringent.

Effects of wire diameter, yarns size and wire configuration to wire cloth electrode produced from textile technology for dielectrophoresis application

Dielectrophoresis (DEP) is one of an alternative way for cell separation. It has mainly been limited to processing small volumes due to constrain in fabrication of microelectrode over large surface areas. This work focuses on optimizing the wire cloth electrode fabricated from the use of textile technology. The plain-weave wire cloth consists of stainless steel wires as the microelectrode arrays and polyester yarn as the insulator. The study involved producing wire cloth electrode with variations of wire diameters, yarn sizes and wire configuration (single or double twisted). Simulation using FEMLAB software was conducted to study the electric field generated from the wire cloth. The performance of the finished wire cloth electrode was then tested by conducting a small-scale separation experiment. It was found that larger diameter wire electrode and smaller yarn size resulted to higher electric field strength. In regards to wire configuration, double twisted wire led to higher electric field intensity and better nonuniformity with 1.25% and 9.29% higher cell separation yield recorded than single wire for 100μm and 71 μm, respectively.