Main Wire Research Articles

Physical characteristics of triple-wire gas indirect arc plasma

The triple-wire gas indirect arc welding (TW-GIA) has advantages of high deposition rate and low heat input. However, due to the lack of accurate understanding of the physical characteristics of arc plasma, the further development of this technology is restricted. In this paper, numerical simulation is used to quantitatively analyze the arc physical characteristics of TW-GIA. The results show that the TW-GIA consists of two separate arcs during the ignition stage, and then gradually couples into a single inverted cone arc. The arc temperature is symmetrical along the main wire. The current density of the stable arc is concentrated at the end of the three wires, and the maximum current density of the main wire end is 2.28–2.92 times that of the side wire. The magnetic field intensity at the symmetrical position along the main wire is in the opposite direction, and the values are basically the same. In the X-axis direction, the energy flow density presents an “M" type characteristic. In the Y-axis direction, as the distance from the main wire increases, the energy flow density first decreases sharply, then slowly increases, and then decreases. The measured arc morphology and electron temperature agree well with the calculated results.

Study on Fatigue Performance of 2200 MPa High-Strength Wire of Main Cables Based on FE-SAFE

In order to estimate the fatigue life of 2200 MPa high-strength steel wire for main cables at the outlet of the cable saddle, a fatigue loading test of a single steel wire was designed, and the value of the friction coefficient in finite element simulation and the scale factor in fatigue life analysis were determined. The fatigue life of the steel wire was analyzed by two-stage modelling. The results showed that the fatigue life of steel wire can be simulated effectively when the friction coefficient is 0.21 and the scale factor is 1.15. The fatigue life of 2200 MPa main cable wire at the saddle outlet is 4.78 million loading cycles. The research results laid a foundation for practical engineering application of high-strength steel wire for 2200 MPa main cables.

Gradual Deterioration Behavior of the Load-Bearing Strength of Main Cable Wires in a Suspension Bridge

The main cable is the primary load-bearing component of a long-span multi-tower suspension bridge. The interaction between a dead load, vehicle load, wind load, and the corrosion environment leads the main cable wire to exhibit tribo-corrosion-fatigue behaviors. This behavior causes wire wear and deterioration, as well as a reduction in the effective cross-sectional area. This leads to the gradual deterioration of the wire’s load-bearing strength and seriously affects the load-bearing safety of the main cable. In order to ensure the safety of suspension bridges, it is critical to investigate the gradual deterioration behavior of the main cable wire’s load-bearing strength. A wire tribo-corrosion-fatigue test rig was established to test the wire under different friction pairs (saddle groove or parallel wires). The cross-sectional failure area of the wire with different pairs was obtained by super-depth electron microscopy and calculation. The damage degree evolution model and the deterioration model of the wire load-bearing strength were established by combining the theory of damage mechanics and the finite element method. The results show that, as contact and fatigue loads increase, so does the cross-sectional failure area of the fatigue steel wire. The fatigue wire’s damage degree has a good quadratic function relationship with fatigue cycles. The damage degree of the wire increases and the load-bearing strength decreases with increasing contact load and fatigue load. The load-bearing strength of the wire changes little at the beginning and decreases with increasing fatigue cycles. The results have fundamental significance for the life prediction of the main cable wires of suspension bridges.

A flexible and self-supported nanoporous gold wire electrode with a seamless structure for electrochemical ascorbic acid sensor

A flexible and self-supported nanoporous gold (S/NP-Au) has been produced using a simple, green, and quick approach for the electrochemical detection of l-ascorbic acid (AA). The dealloying process was used to create the main porous gold wire, and then electrochemical anodizing was adopted to construct the fine structure for nanoporous electrode. Furthermore, followed by chemical reduction with the enediol group in AA, the surface of S/NP-Au wire changed from a laminated to a scattered structure, and the preferred Au (2 0 0) high-index plane was investigated. As a result of synergistic electrocatalytic activity of Au wire skeleton towards AA, amperometric AA electrochemical sensors based on the S/NP-Au wire electrodes exhibit linear detection ranges with ultrahigh sensitivities at a low potential of 0.20 V (vs Ag. AgCl). The detection range of 0.3 μM–923.3 μM with a short response time of less than 1 s gives rise to ultralow detection limit of 26.3 nM (S/N = 3). The excellent characteristics of this sensor demonstrates it is a useful tool for accurate determination of AA in commercially available beverages such as water-soluble beverages with recoveries of 97.35 % to 110.7 %. The S/NP-Au electrode is a promising material for non-enzymatic AA detection.

Process Stability and Material Properties of TC4 Alloy Welded by Bypass Current Hot Wire Plasma Arc Welding (BC-PAW)

To improve welding efficiency, bypass current hot wire plasma arc welding (BC-PAW) was employed to weld Ti-6Al-4V alloy. The influence of process variables on metal transfer behaviour was explored using high-speed camera, and the material properties were investigated by means of different microscopes and mechanical test. The result shows that the weld seam has a good surface finish without welding defects. The main current, bypass current, and wire feeding speed have a significant influence on the metal transfer behaviour, which further influence the grains’ formation in the weld zone. The microstructure of the weld mainly comprises α martensite and the average tensile strength (UTS) of the as-received joint is 986 MPa, which is larger than that obtained using the conventional PAW method. The fracture occurs in the heat-affected zone (HAZ), which shows a typical ductile fracture surface.

Surgical Orthodontic Treatment of Class II Malocclusion with Facial Asymmetry

This case report describes a successful surgical orthodontic treatment of a Class II malocclusion with facial asymmetry. An 18-year-old female visited our dental clinic due to proclined anterior teeth and facial asymmetry. Straight facial profile and skeletal Class II was observed. The frontal cephalometric analysis showed that the left ramus length was longer and the left ramal angle was greater than the right. After extraction of the maxillary and mandibular second premolars, dental arch was decompensated. After presurgical orthodontic treatment, bilateral sagittal split ramus osteotomy (BSSRO) was performed. Facial asymmetry was improved, but posterior open bite on the right was occurred by insufficient dental decompensation. To prevent recurrence of the mandible, a bite stop was made by bonding resin on the lingual side of the right maxillary canine. This prevented the recurrence of the mandibular rolling and yawing with the use of bilateral intermaxillary elastics. The right mandibular posterior part with open bite was segmented from the main arch wire and was extruded with intermaxillary elastic. Fast occlusal stabilization was achieved by using the rapid tooth movement after surgery. Since intermaxillary elastic was used while applying an intrusion force with a micro-implant to the left posterior region, it was possible to stabilize the mandible while prevent tooth extrusion. After treatment, facial symmetry and good occlusal relationship were achieved.

Experimental Research on the Apparent Corrosion Law of a Suspension Bridge’s Main Cable Steel Wire under Status of Holding Force

Regarding the corrosion law of a suspension bridge’s main cable steel wire under the status of holding force, a set of electrolytic-accelerated corrosion test devices with preload was designed. The electrolytic-accelerated corrosion test of the main cable steel wire of a suspension bridge under the status of holding force was carried out. A total of 60 steel wires with diameter 5.25 mm were selected under four working conditions of 0, 1,000, 2,000, and 3,000 μϵ. The quality and diameter of steel wire after 0–4 days of electrolytic-accelerated corrosion were measured. Additionally, the change law of the average mass loss rate and cross-sectional loss rate of the main cable steel wire with strain and time growth were discussed. The results of the tests showed that with the increase of strain level and corrosion time, the corrosion of steel wire under the stress state is more obvious, the fluctuation of local characterization is more intense, and the corrosion presents a nonlinear growth trend. The mass loss of the steel wire with 3,000 μϵ after four days of accelerated electrolytic corrosion is similar to the 420-day test result of natural corrosion, and the change trend is consistent. Under accelerated corrosion conditions, the average mass loss rate of a steel wire with 3,000 μϵ after four days of accelerated electrolytic corrosion is 6.40 times that of one day. At the same time, the average mass loss rate of steel wire with 3,000 μϵ after one to four days of accelerated electrolytic corrosion are 1.17 times, 1.22 times, 2.27 times, and 3.02 times than 2,000 μϵ respectively. The maximum section loss rate increases with the increase of strain and time, and it has a good correlation with the two variables. Therefore, the maximum section loss rate can be considered as the core intermediate variable to measure the corrosion grade of main cable steel wire.

Analysis of metal transfer and weld forming characteristics in triple-wire gas indirect arc welding

Triple-wire gas indirect arc welding (TW-GIA) has the advantages of low heat input and high deposition rate. However, the simultaneous melting of triple wires makes the metal transfer mode complicated. The unknown of the metal transfer mode restricts the development of this technology. In this paper, high-speed camera systems and electrical signal acquisition sensors were used to explore the TW-GIA metal transfer mode. The static force model and the arc conductive channel model were used to discuss the droplet force and energy conversion characteristics, respectively. Results showed that the TW-GIA metal transfer modes can be divided into the following: short-circuit transfer (SCT), main wire projected transfer + side wire globular transfer (PGT), main wire streaming transfer + side wire projected transfer (SPT), and main wire streaming transfer + side wire streaming transfer (SST). Moreover, the process parameter ranges corresponding to the four modes were summarized. Due to the stable arc and the uniform metal transfer process, SPT and SST can form desirable weld seam. The gravity and z-axis components of electromagnetic force are the main forces that promote metal transfer. The x-axis and y-axis components of the electromagnetic force deviate the metal transfer path from the arc coverage. Due to the change of arc conductive channel, the energy transferred from TW-GIA to the base metal is less than that of gas metal arc welding, showing the advantages of small welding deformation, narrow heat-affected zone, and grain refinement.

Analysis of Structural Characteristics of Underground Cavern Group by Simulating All Cavern Excavation

The traditional Three‐dimensional (3D) model for stability analysis of a large underground cavern group only includes the main powerhouse, the main transformer chamber, the tailrace surge tank, the main electrical wire hall, and part of the diversion tunnel and tailwater tunnel. Other caverns excavation are not taken into consideration, which is inconsistent with the actual project. In this study, a 3D Finite Element Method (FEM) model, including all the cavities, and a 3D simplified model containing only part of the cavities were established based on the actual underground cavern group project. We study the structural characteristics of the cavern group during excavation via 3D nonlinear FEM. At the same time, three numerical calculation schemes are designed for comparison. The results show that the simulated distributions of the stress field, deformation field, and plastic zone of the two numerical models are similar, but the magnitudes of the 3D FEM model, which considers all caverns are generally higher than the simplified model. The difference between the two simulated horizontal displacements of the main powerhouse reaches 53.72%. Therefore, from the perspective of engineering safety and actual construction, it is advisable to adopt the 3D FEM model, including all the cavities, when conducting a simulation analysis of the underground cavern group.

Web-Based Simulation Environment for Vehicular Electrical Networks

For the validation of vehicular Electrical Distribution Systems (EDS), engineers are currently required to analyze disperse information regarding technical requirements, standards and datasheets. Moreover, an enormous effort takes place to elaborate testing plans that are representative for most EDS possible configurations. These experiments are followed by laborious data analysis. To diminish this workload and the need for physical resources, this work reports a simulation platform that centralizes the tasks for testing different EDS configurations and assists the early detection of inadequacies in the design process. A specific procedure is provided to develop a software tool intended for this aim. Moreover, the described functionalities are exemplified considering as a case study the main wire harness from a commercial vehicle. A web-based architecture has been employed in alignment with the ongoing software development revolution and thus provides flexibility for both, developers and users. Due to its scalability, the proposed software scheme can be extended to other web-based simulation applications. Furthermore, the automatic generation of electrical layouts for EDS is addressed to favor an intuitive understanding of the network. To favor human–information interaction, utilized visual analytics strategies are also discussed. Finally, full simulation workflows are exposed to provide further insights on the deployment of this type of computer platforms.

Transient impedance of grounding system with impulse superimposed sinewave

Investigating the transient performance of grounding systems subject to lightning (impulse or impulse superimposed sinewave) is valuable for protecting the power system and maintaining the system operation. In this work, the grounding system's impedance is computed when an impulse superimposed sinewave is applied to the grounding grid's proposed lumped circuit and grounding system can be simulated as an inductance in series with resistance, and all of them are in parallel with capacitance based on Thione's assumption. Several variables were investigated to study their effects on the grounding system's behavior. The variables were the soil resistivity, soil permittivity, main wire length, grid conductor radius, grid side length, grid configurationand its mesh number. The grounding system configuration varied between square and rectangular shapes, which connects to the protecting rod via the main wire conductor. A 3.69 kA peak of impulse current was applied to avoid soil ionization. The results indicated the performance of the grounding system when subjecting to impulse current.

Tunneling into a Luttinger liquid coupled to acoustic phonons out of equilibrium

The renormalization of conductances in a Y junction of spinless Luttinger-liquid wires additionally coupled to acoustic longitudinal phonons is investigated in fermionic representation. This system corresponds to geometry of a tunneling experiment and exhibits the interplay between the Coulomb repulsion and the attractive retarded interaction mediated by phonons. The retardation effects related to the propagation of phonons through the junction with arbitrary transmission and reflection amplitudes are taken into account. The appearing logarithmic corrections to conductances of the junction are treated in a renormalization group approach, and scaling exponents are calculated up to infinite order in the interaction after RPA-type summation. The fixed points and corresponding scaling exponents are considered in various non-equilibrium regimes. We show that the boundary exponent and the bulk anomalous dimension of fermion operator are characterized by two different Luttinger parameters, referring to the main wire, thanks to non-local character of phonon-mediated interaction. In the limiting case of the junction of only two wires, the scaling exponents found by our method are in exact correspondence with previous bosonization analysis.

A Study of Inspection for Electrical Safety Systems Case Study Four Locations in Thailand

This research presents study of inspection for electrical safety in electrical system. The four locations are observed. The objective of this research are to study the problems which may be occurred in electrical system and introduce the prevent ways. The four locations consist of 2 factories of paper and 2 animal food factories. For factory of paper, the total electrical load is 18,450 kVA which consists of 10 transformers and another 13,450 kVA which consists of 10 transformers. For the animal food 800 kVA, another is 1000 kVA which each location is a transformer. The inspected systems include transformer, main distribution board, ground and electrical wire systems. The check instruments are test oil maker, thermo scan, earth clamp tester, earth ground tester, infrared tester and outlet tester. The all data from test is analysed to compare among of four locations. For experimental results, it is of found that for transformer, the oil insulation transformer is lower than standard and silica gel is deteriorated and broken box, rubber shield and rubber gasket is broken and damage. For main distribution board, the ground value is lower than standard and the temperature of junction for breaker is high and more dust. For ground system, the ground value is lower than standard and broken. For wire system, the electrical is damaged because of heat and animal.

A Non-Intrusive Load Monitoring System Based on Blacklist Detection

Electric utilisation safety is widely recognised as an important issue. Most electrical accidents can be concluded to the unallowed access of certain kinds of electrical appliances, hence can be effectively prevented by a blacklist-based detection. However, this ability is lacked in many of the existing Non-Intrusive Load Monitoring (NILM) system. This paper proposes a novel blacklist-based NILM system capable of extracting valuable information from the main wire when unallowed risky appliances are switched on in a household. Comprehensive methods are proposed to optimise the accuracy of detection and the self-learning ability on blacklist extension. Experimental results show that the proposed methods yield outstanding performance. The proposed system is applicable for unallowed appliances management, from the inhabitants or from the grid operator’s point of view.

Imperfections in narrow gap multi-layer welding - Potential causes and countermeasures

Narrow Gap Multi-Layer Welding (NGMLW) using a laser as the main heat source and metal wire for material addition has been a growing topic of interest in the last decade. This is in part due to its potential for joining much thicker sheets of steel than what is usually considered possible when using autogenous laser welding. The process has shown great potential but improvements can still be made, e.g. through increased process control to decrease welding imperfections. Using closed-loop control, where the process is continuously monitored and regulated automatically, can help to account for variations during manufacturing. However, achieving functional closed loop control can be challenging due to limitations in data gathering and processing speeds. Important initial steps include identifying what data can be useful and how frequently this data has to be recorded. Too much data takes too long to process while too little causes risks of missing important details. In this study, 20 mm thick X80 pipeline steel sheets are joined together using this multi-layer approach; the samples are examined using 3D scanning and Computed Tomography (CT) analysis and the process is observed using High-Speed Imaging (HSI). The quality of the welded joint and welding imperfections are discussed and potential points of formation are identified. Suggestions on how to mitigate imperfections to improve the quality of the welded joint are presented, including the potential to use camera imaging for closed-loop process control and additional industrial uses of the HSI footage.

Emergent chirality in multilead Luttinger-liquid junctions out of equilibrium

We study charge transport through $N$-lead junctions ($N\geq 3$) of spinless Luttinger liquid wires with bias voltages applied to Fermi-liquid reservoirs. In particular, we consider a Y junction, which is a setup characteristic of the tunneling experiment. In this setup, the strength of electron-electron interactions in one of the arms ("tunneling tip") is different from that in the other two arms (which form together the "main wire"). For a generic single-particle $S$ matrix of the junction, we find that the bias voltage $V$ applied---even symmetrically---to the main wire generates a current proportional to $|V|$ in the tip wire. We identify two mechanisms of this nonequilibrium-induced "emergent chirality" in a setup characterized by the time-reversal and parity symmetric Hamiltonian of the junction. These are: (i) the emergence of an effective magnetic flux, which breaks time-reversal symmetry, and (ii) the emergence of parity-breaking asymmetry of the setup, both proportional to the interaction strength and the sign of the voltage. The current in the tip wire generated by mechanism (i) is reminiscent of the Hall current in the linear response of a system the Hamiltonian of which breaks time-reversal symmetry; however, in the absence of any magnetic field or a local magnetic moment. Similarly, mechanism (ii) can be thought of as an emergent "photogalvanic effect"; however, in the presence of inversion symmetry within the main wire. The nonequilibrium chirality implies a rectification of the current in the tip when the main wire is biased by $\it ac$ voltage.

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.

Effect of Main Cut and Multiple Trim Cuts on Surface Integrity of 2379 Steel

Wire electrical discharge machine (WEDM) is commonly used in producing tool and die parts. However, it rarely achieves the optimum machining condition due to the inappropriate selection of WEDM machining parameters. In this study, 2379 steel which own properties equivalent to SKD 11 was used as die material. Four main wire electrical discharge machine (WEDM) cutting parameters, namely pulse on time, pulse off time, servo voltage, ignition pulse current has been experimentally studied and optimized at both levels, main cut and multiple trim cuts using Taguchi Method. Based on Taguchi Method optimization and analysis of variance (ANOVA), the result found that pulse on time and pulse off time give significant effect on white layer thickness for both main cut and multiple trim cuts. According to Signal to Noise (S/N) ratio response, the optimal combination of A2B3C2D1 and A1B3C3D1 gave the lowest white layer thickness for main cut and multiple trim cuts respectively. It also has been found that the hardness of machined surface with multiple trim cuts is higher compared to main cut.

English

Study on the poaching and bushmeat off takes /harvest in the Ebo Forest Reserve was carried out in 2012 and 2016 to identify and quantify species poached, poaching methods and seasonal impact on harvest rates and quantity. To achieve this task, purposeful and random sampling methods were used for the selection of respondents for questionnaires administration. In all, 182 from a population of about 461 poachers were sampled for questionnaires administration. Besides the administration of questionnaires, some selected Participatory Rural Appraisal (PRA) tools were also employed for the triangulation of collected data. Biological data were collected using four transects each 1.8 m wide by 2 km long laid 200 m apart in each of the zones. Along each of the established transects 20 m on both sides, data on encounter rates and human presence was collected. A total of 3768 animals with biomass of 26039.5 kg was harvested from the Ebo Forest Reserve and associated forests areas by 461 poachers. The harvest was made up of 30 species from 17 families of wildlife dominated by blue duikers (19.59%), brush- tailed (18.10%) and red duikers (11.36%).Two main weapons, guns and wire snares were identified as the main poaching weapons in the EFR. Harvest was more in the wet season than in the dry season. Poaching was more intense in zones that were very accessible and close to the market centre of Douala. As income gain remained a driving force to poaching, there is need to check poaching activities in the study area against the present weekly off take rate of 2.87 animals per day. Key words: Bushmeat, off take, poaching, harvest, species.

Novel Degradation Mechanism of a Structural Wire Rope During Its Life Cycle

High-carbon steel wire ropes are used for various high-load-bearing applications. They achieve tensile strength of the order of 2 GPa owing to a combination of fine pearlitic microstructure and work hardening during the drawing process. Despite these high strength levels, they can fail during service due to either manufacturing defects or service abuse. In this study, failure analysis of main hoist steel wire rope used in a basic oxygen furnace (BOF) was carried out. Several locations of the wire rope showed unprecedented microstructural degradation. The presence of surface martensite with transverse cracks was observed in severely abraded wires. Some locations of the rope revealed fusion of adjacent wires with increased interlamellar spacing of pearlite and formation of divorced pearlite in heat-affected and fusion zones, respectively. A significant variation in hardness across the wire rope was noted due to these in-service microstructural changes. Such macroscopic and microstructural deterioration has not been reported in open literature. Detailed failure analysis of the wire rope along with a novel theory explaining the mechanisms of such microstructural degradation is presented herein. This study confirms that the wire rope suffered premature damage due to improper lubrication during service that led to direct metal-to-metal contact, associated friction, abrasion, and fusion of wires. Excessive friction and abrasion of wires subsequently led to fatigue of some of the wires, as manifested by square or crown breaks and striation marks.