Flat Wire Research Articles

Analysis of Molten Pool Characteristics on Hybrid GMAW Process

This paper presents a complementary experimental and numerical investigation of thermal and welds bead characteristics of GMAW for flat wire electrode (FE-GMAW). The welding parameters for the FE-GMAW process are Welding Current (I), Stick out Distance (SD), Welding Speed (WS), Gas flow rate (Q), Welding feed rate (f) and Dimensions of the Flat Electrode (DFE) which have the most effect on the weld bead performance as consider. To analyses the effect of weld bead performance a FEA simulation is carried out using Ansys apdl for transient thermal analysis. The analysis with different combinations of the parameters such as voltage, current, and efficiency. From the analysis, temperature distribution is evaluated for the weld bead and the results of numerical are compared with the experimental values. This paper also deals with thermal and droplet characteristics in GMAW for flat wire electrode (FE-GMAW). By considering the above mentioned welding parameters the characteristics of the weld samples are analyzed, and also investigate droplet and thermal characteristics such as droplet formation, detachment, transfer and impingement and their temperature difference during the FE-GMAW process. Then, Computational Fluid Dynamics (CFD) package, CFX which employ the volume of fluid (VOF) method is to be carried out to understand the droplet and thermal characteristics and predictions were compared with experimental results.

Using wire shaping techniques and holographic optics to optimize deposition characteristics in wire-based laser cladding.

In laser cladding, the potential benefits of wire feeding are considerable. Typical problems with the use of powder, such as gas entrapment, sub-100% material density and low deposition rate are all avoided with the use of wire. However, the use of a powder-based source material is the industry standard, with wire-based deposition generally regarded as an academic curiosity. This is because, although wire-based methods have been shown to be capable of superior quality results, the wire-based process is more difficult to control. In this work, the potential for wire shaping techniques, combined with existing holographic optical element knowledge, is investigated in order to further improve the processing characteristics. Experiments with pre-placed wire showed the ability of shaped wire to provide uniformity of wire melting compared with standard round wire, giving reduced power density requirements and superior control of clad track dilution. When feeding with flat wire, the resulting clad tracks showed a greater level of quality consistency and became less sensitive to alterations in processing conditions. In addition, a 22% increase in deposition rate was achieved. Stacking of multiple layers demonstrated the ability to create fully dense, three-dimensional structures, with directional metallurgical grain growth and uniform chemical structure.

Electrochemical Impedance Spectroscopy at Well‐Controlled dc Bias for Nanoporous Platinum Microelectrodes in Rat Embryo Brain

AbstractNanoporous Pt with extremely small (1–2 nm) and uniform nanopores, L2‐ePt, is electrochemically investigated in rat embryo brain. In a comparative study under precise control of electrochemical potential, an electrochemical cell beneath the brain surface is constructed by introducing flat and nanoporous Pt twisted wires around which Ag/AgCl is wound. L2‐ePt and flat Pt in the brain are compared with each other by conventional voltammetry and electrochemical impedance spectroscopy at the dc bias, which is carefully selected to minimize faradaic interference. The electrochemical behavior at L2‐ePt implanted into embryo brain is immune to severe passivation and is closer to an ideal capacitor than flat Pt. A lower electrode impedance of L2‐ePt leads to less potential drop at the interface between the electrode and the extracellular solution, protecting the implanted system from unwanted faradaic reactions. Various aspects, including the low electrode impedance and electrochemical stability in embryo brain, suggest that L2‐ePt is a promising electrode material for effectively stimulating distant neuronal cells and recording local field potential signals.

Analysis of weld bead characteristics on GMAW by changing wire electrode geometry

Purpose: Welding is one of the important processes for the manufacture of a wide varietyof products. Most of the manufactured products have to be produced by welding due to itsgreater productivity and economical viability. Still quality has to be enhanced in the products.To attain the perfect quality in weld a new attempt has been tried out while existing processare being optimized. In this direction, the conventional Gas Metal Arc Welding (GMAW) hasbeen developed to encourage high welding performance variant. Influence of changingfiller metal geometry is one of the ways to improve the capability of giving high depositionrate and penetration. Accordingly, a flat wire arc welding system has been developed andweld bead characteristic has been investigated. The overall results show that, the proposedtechnique of changing wire electrode geometry can be used effectively to improve the weldbead characteristics. In this article, how does a change in electrode geometry contribute tothe weld quality in manufacturing industries, is well- verified by experimental results, whichare also explored here.

Inverse modelling approach in 3-point bending for elasto- plastic material parameter identification of thin spring steel

Under process conditions such as bending of flat wire made from high strength spring steel, the occurring strains are many times higher than the maximum strains determined from uniaxial tensile tests. To determine the elasto-plastic material behaviour of high strength spring steel (X10CrNi18-8), an inverse modelling approach using a simple testing method is presented. A 3-point bending test with the resulting force-displacement measurements is used for the inverse analysis. The inverse approach is used for determining the Young's modulus and hardening parameters of the Ludwik-Hollomon's law for bending of high strength spring steel. FE simulations with the optimised material data meet the experimentally measured punch forces during bending. The optimised material data considerably enhances the springback prediction.

Measurement of pH and calcium ions release from different calcium hydroxide pastes at different intervals of time: Atomic spectrophotometric analysis

AimTo evaluate the effect of different vehicles on pH and release of calcium ions from calcium hydroxide (CH) paste from apical third of root canals. Methods40 single rooted extracted human mandibular premolars were instrumented with RevoS files (MicroMega) up to ISO size 40. The teeth were divided into 4 groups on the basis of vehicle as follows: Group I – calcium hydroxide mixed with 2% chlorhexidine; Group II – calcium hydroxide mixed with propylene glycol; Group III – calcium hydroxide mixed with glycerine; and Control – calcium hydroxide mixed with double distilled water. Each group had two subgroups (n=5) on the basis of the calcium hydroxide delivery. Subgroup A – calcium hydroxide paste placed with spiral filler (Lentulospiral) subgroup B – calcium hydroxide paste placed with flat wire filler (Paste Inject). pH and calcium ion release was evaluated at 24h, 48h, 7th day, 15th day and 30th day using a pH meter and atomic absorption spectrophotometer respectively. ResultsThe calcium release from various groups was highest for CH+glycerine (Group III) followed by CH+chlorhexidine (Group I), CH+propylene glycol (Group II) and CH+double distilled water (control). At all the intervals the differences in calcium ion release among the groups were statistically significant (p<0.05), except on day 7. Delivery technique did not have a significant effect on calcium ion release. Highest pH values were recorded from CH+glycerine group at day 30 for both the delivery systems, however rise in pH from day 1 to day 30 were non-significant in all groups with both delivery systems. ConclusionDemonstrable changes in calcium ion release occurred from the calcium hydroxide mixed with various vehicles and CH+glycerine group showed the maximum calcium ion release at all intervals and highest pH day 30.

Mechanical Calculation of Power Lines and Strands in Overhead Transmission Lines

This paper discusses the issue of shape and stress of overhead transmission lines. It fully considers that the conductor is subjected to axial force, shear, bending moment simultaneousiy. And the flat wire is basically in the elastic range. Because the stress is the strength of a certain point, the bending rigidity of the overhead lines can not be ignored. However, the catenary has been used in previous research and the force of the overhead lines is obtained on this basis. The author establishes a model of wire calculation under real condition, and gives a feasible simplified model. And then it gives the line shape formula, internal force formula, formula of stress in the strands. The results show that the original stress is significantly smaller.In this paper, the stress formula is almost close to the reality. It proves the reliability of the simplified model that the line shape includes the original flexible part.The results can not only fill the gaps in the theoretical study of the overhead lines, but also have some guidance to the production and design of overhead lines.

Radiation of relativistic electrons in a periodic wire structure

We present in this work the experimental investigation of the interaction of relativistic electron field with periodic wire structures. We used two types of the targets in experiments: flat wire target and sandwich wire target that represent the right triangular prism. The measurements were done in millimeter wavelength region (10–40mm) on the relativistic electron beam with energy of 6.2MeV in far-field zone. We showed that bunched electron beam passing near wire metamaterial prism generates coherent Cherenkov radiation. The experiments with flat wire target were carried out in two geometries. In the first geometry the electron beam passed close to the flat wire target surface. In the second case the electron beam passed through the flat wire structure with generation of a coherent backward transition radiation (CBTR). The comparison of the Cherenkov radiation intensity and BTR intensity from the flat wire target and from the flat conductive target (conventional BTR) was made.

Preparation of a nanostructured shape-memory composite material for biomedical applications

We have obtained nanoscale and microscopic surface tantalum layers on NiTi flat substrates and wires. The structure and composition of the samples were determined by scanning electron microscopy, Auger electron spectroscopy, and X-ray diffraction. With increasing sputtering time, the thickness of the surface layer increases nonlinearly. The transition layer ensures strong adhesion of the surface layer to the substrate.

Comparison of growth texture in round Bi2212 and flat Bi2223 wires and its relation to high critical current density development.

Why Bi2Sr2CaCu2Ox (Bi2212) allows high critical current density Jc in round wires rather than only in the anisotropic tape form demanded by all other high temperature superconductors is important for future magnet applications. Here we compare the local texture of state-of-the-art Bi2212 and Bi2223 ((Bi,Pb)2Sr2Ca2Cu3O10), finding that round wire Bi2212 generates a dominant a-axis growth texture that also enforces a local biaxial texture (FWHM <15°) while simultaneously allowing the c-axes of its polycrystals to rotate azimuthally along and about the filament axis so as to generate macroscopically isotropic behavior. By contrast Bi2223 shows only a uniaxial (FWHM <15°) c-axis texture perpendicular to the tape plane without any in-plane texture. Consistent with these observations, a marked, field-increasing, field-decreasing Jc(H) hysteresis characteristic of weak-linked systems appears in Bi2223 but is absent in Bi2212 round wire. Growth-induced texture on cooling from the melt step of the Bi2212 Jc optimization process appears to be the key step in generating this highly desirable microstructure.

When the Midline Diastema Is Not Characteristic of the "Ugly Duckling" Stage.

This case report presents the interceptive orthodontic treatment of a 9-year, 5-month-old boy with class I malocclusion, a 9.0-mm maxillary midline diastema, and deviation from the midline. The treatment goals were to decrease the magnitude of the diastema and to simulate the characteristics of the “ugly duckling” stage. Braces were placed on the first molars and the maxillary central incisors. The biomechanics of the anchors on the first molars elicited substantial mesial movement of the left central incisor to match the midline. A flat wire segment was bonded onto the palatal surface of the central incisors for retention.

AVALIAÇÃO DO CONJUNTO MOTOR GERADOR MONOFÁSICO ALIMENTADO COM BIOGÁS PURIFICADO DA FERMENTAÇÃO ANAERÓBIA DE DEJETOS DE SUÍNOS - DOI: 10.13083/1414-3984.v22n04a04

A geração de energia elétrica a partir de dejetos orgânicos da agropecuária ainda é muito incipiente no Brasil. Diante disso, o objetivo deste trabalho foi avaliar a viabilidade técnica da utilização de um conjunto motor gerador, monofásico de 30 kVA, para geração de energia elétrica, por meio da combustão do biogás purificado. Utilizaram-se três processos físicos e químicos de remoção do sulfeto de hidrogênio: Filtragem via úmida (0,1 m3 de H2O mais 20 kg de CaO e 10 kg de carvão vegetal); filtragem via seca (50 kg de arame liso recozido no 06 e 10 kg de carvão vegetal); filtragem em série (filtragem via úmida seguido da filtragem via seca) com os recheios dos filtros nas mesmas proporções. Avaliou-se o desempenho do conjunto motor gerador em função do tempo de funcionamento. Com base nos resultados, pode-se concluir que os sistemas de filtragem, em média, reduziram as emissões de CH4 e SO2 do conjunto motor gerador e mantiveram constantes as emissões de H2S. A filtragem via úmida com hidróxido de cálcio possibilitou o maior rendimento teórico e observado do conjunto motor gerador, que foi de 29% e 12%, respectivamente.

Bacterial chondronecrosis with osteomyelitis in broilers: Influence of sires and straight-run versus sex-separate rearing

Two experiments (E1, E2) were conducted to compare the influence of sires (sire A on dam C vs. sire B on dam C) and straight-run versus sex-separate rearing on the incidence of bacterial chondronecrosis with osteomyelitis (BCO) in broilers. Fertile eggs from commercial breeder flocks were incubated and hatched at the University of Arkansas Poultry Research Hatchery. Male and female chicks were reared together (straight-run) or separately (sex-separate) in 3 × 3 m pens on litter or flat wire flooring with 65 (E1) or 60 (E2) birds per pen. Necropsies revealed lesions that are pathognomonic for BCO in ≥98% of the birds that became lame. The SigmaStat Z-test was used to compare cumulative BCO incidences through 8 wk of age. For birds reared on litter, the incidences of BCO were low regardless of cross or sex (range: 1.7 to 5.1%; P ≥ 0.6). Within a cross and sex, rearing the broilers straight-run versus sex-separate on wire flooring did not significantly affect the incidence of BCO. Significant incidences of BCO did not develop until after d 40. Males from the sire A cross developed a higher incidence of BCO than males from the sire B cross in E1 (27 vs. 17%, respectively; P = 0.009) but not in E2 (28.5 vs. 22.6%, respectively; P = 0.141). In both experiments, males from the sire A cross developed higher incidences of BCO than females from the sire B cross (27 vs. 11.9%, in E1; 28.5 vs. 14.8%, in E2). With the sexes pooled, broilers from the sire A cross consistently developed higher incidences of BCO than broilers from the sire B cross (21.4 vs. 14.9%, P = 0.005 in E1; 26.5 vs. 18.7%, P = 0.003 in E2). High susceptibilities to both femoral head (all femoral head necrosis = 66 to 85% incidences) and tibial head (all tibial head necrosis = 81 to 96% incidences) BCO lesions were demonstrated in lame birds from both sexes and crosses. This study supports a sire influence on the susceptibility of broilers to BCO. Sire lines can be chosen to reduce BCO susceptibility when broilers are grown beyond 6 wk of age.

Evaluating portable wire-flooring models for inducing bacterial chondronecrosis with osteomyelitis in broilers

Rearing broilers on flat or sloping wire flooring is an effective method for consistently triggering lameness attributable to bacterial chondronecrosis with osteomyelitis (BCO). Portable obstacles known as speed bumps (SB) also consistently trigger modest incidences of BCO when they are installed between feed and water lines in litter flooring facilities. Two experiments were conducted to determine the most effective broiler age for introducing the SB into litter flooring pens, and to evaluate alternative configurations of the traditional SB with the expectation that amplified mechanical challenges to the legs of broilers should increase the incidence of BCO. Broiler chicks obtained from commercial hatcheries (lines B and D in experiment 1, lines A and B in experiment 2) were reared in floor pens with ad libitum feed and water and a 23L:1D photoperiod. In experiment 1, the 5 floor treatments included wood shavings litter only (L), flat wire only (W), or litter plus SB installed at 14, 28, or 42 d of age. Line B was more susceptible to lameness than line D (25.9 vs. 15.3% for all treatments combined; P = 0.001). Both lines developed low incidences of lameness on L (11 to 13%), intermediate incidences on SB regardless of day of installation (12 to 23%), and high incidences on W (21 to 39%). In experiment 2, broilers were reared with 7 floor treatments, including L, W, SB with a 50% slope (SB50%); SB50% with a limbo bar installed over the apex; SB with a 66% slope and limbo bar; SB50% with a nipple water line suspended over the apex; and a pagoda-top SB. All SB were inserted on d 28. Line B was more susceptible to lameness than line A (20.2 vs. 16.1% for all treatments combined; P < 0.05), and for both lines combined the lameness percentages averaged 7.7 (L), 29.2 (W), 17.3 (SB50%), 16.2 (SB50% with a limbo bar), 21.5 (SB with a 66% slope and limbo bar), 20.8 (SB50% with a nipple water line), and 11.5% (pagoda-top). These studies demonstrate the portable SB can be effectively used to experimentally trigger BCO in broilers.

PREDICTION OF TENSILE AND FRACTURE PROPERTIES OF CRACKED CARBON STEEL WIRES USING FINITE ELEMENT SIMULATION

Steel wires are used as a bridge construction material and as pre-stressing strands or tendons in pre-stressed structural units among other applications in civil engineering. To date, the estimation of the load carrying capacity of a cracked wire has been based on purely experimental classical fracture mechanics work conducted with non-standardised classical fracture mechanics specimens as standard test specimens could not be manufactured from the wire owing to their size. In this work, experimental mechanical tests and finite element simulation with the phenomenological shear fracture model has been conducted to investigate the effect of miniature cracks with dimensions less than or equal to 0.2 mm (which is the limit of the current non-destructive detection technology) on the tensile and fracture properties of flat carbon steel wire. The investigation revealed that the reduction in the displacement at fracture of the wire due to the presence of cracks shallower than 0.2 mm is significantly higher than the reduction in the fracture load of the wire. Consequently, the displacement at fracture and by extension the fracture strain capacity of the wire could serve as a more appropriate parameter to assess the quality and the structural integrity of cracked wires.

Damage Prediction Using Several Types of Macro-scale Damage Models in Different Cold Wire Production Lines

The purpose of the present paper is to show how and to what extent the introduction of refined, shear sensitive models improves on previous ones, based on triaxiality only, for the phenomenological description of ductile damage in bulk cold metal forming processes. Wire-drawing and wire rolling are taken as examples. A set of mechanical tests has been conducted: round bar tension, notched bar tension, plane strain tension, and torsion for pure shear deformation. Both constitutive and damage model parameters have been carefully identified, with back-computation of the laboratory tests for validation. Application of the models to the cold forming processes, described here, shows the superiority of the shear-enhanced models for locating maximum damage in flat wire rolling, where a significant amount of shear is present (“blacksmith's cross” deformation pattern). On the contrary, it proves unnecessary for low-shear processes such as wire-drawing. The cavity-growth Gurson-Tvergaard-Needleman model seems to be the best basis for damage prediction in patented high carbon steel, a very ductile material.

Design, Modeling and Structural Analysis of Wave Springs

Wave springs are precise flat wire compression springs that fit into assemblies that other springs cannot since the overall lengths and operating heights of Wave springs are lower than those of conventional round Wire springs, they will often reduce the size of an assembly by as much as 50%. Of course, this will also reduce the part weight and raw material cost of every spring produced. Wave springs operate as load bearing devices. They take up play and compensate for dimensional variations within assemblies. A virtually unlimited range of forces can be produced whereby loads build either gradually or abruptly to reach a predetermined working height. This establishes a precise spring rate in which load is proportional to deflection. Functional requirements are necessary for both dynamic and static spring applications. Special performance characteristics are individually built into each spring to satisfy a variety of precise operating conditions. Typically, a wave spring will occupy an externally small area for the amount of work it performs. The use of this product is demanded, but not limited to tight axial and radial space constraints. In this paper, a three dimensional finite element (FE) model for shock absorber spring is proposed. The present work deals the structural analysis for modelling the structural behaviour of wave springs. The design of spring in suspension system is very important. In this work a wave type of spring is designed and a 3D model is created using Pro/Engineer. The model is also changed by changing the length of the spring. Structural analysis has been conducted on the wave spring by varying the spring material such as Structural steel and Beryllium Copper. For this analysis, loads are considered as bike weight, single person and two persons. Structural analysis is done to validate the strength. The present study makes an attempt to compare the results for selecting best material for springs.

Ureteroscopic Biopsy of Upper Tract Urothelial Carcinoma: Comparison of Basket and Forceps

To compare two different biopsy devices for upper tract urothelial carcinoma (UTUC) and evaluate the pathologic result obtained by these devices. From January 2008 to December 2010, 414 ureteroscopies were performed and 504 biopsies were taken for evaluation of UTUC. Two biopsy devices were compared: 2.4F stainless steel flat wire basket and 3F cup biopsy forceps. The effect of the biopsy device on obtaining an adequate pathologic specimen was evaluated using univariate and multivariate binary logistic regression analysis. We also investigated whether tumor grade determination was affected by the biopsy device among patients with a diagnostic biopsy. Diagnosis was successful in 63% and 94% in the forceps and basket groups, respectively (P < 0.0001). Among biopsies with a definite diagnosis of UTUC, specific grade was determined in 80% and 93% in the forceps and basket groups, respectively (P = 0.033). In subgroup analysis of tumors larger than 10 mm in diameter, diagnosis was obtained in 80% and 94% in the forceps and basket groups, respectively (P = 0.037). Cytologic evaluation was found to increase diagnostic rates. The stainless steel flat wire basket was shown to be superior to the 3F cup biopsy forceps in terms of obtaining tissue diagnosis and providing specific grade.

Detection of nanosecond optoacoustic pulses in steel

The optoacoustic transformation of 5-ns laser pulses was used to excite broadband longitudinal acoustic pulses in a 0.4-mm-thick steel plate. An electromagnetic acoustic transducer that incorporated a flat wire coil with a diameter of 5 mm and an amplifier was proposed as a device for contactless ultrasound detection. A permanent cylindrical magnet and a coil close to the printed-circuit board of an operational amplifier were placed on one side of the sample, thus allowing the detection of the alternating electromagnetic field produced by pressure pulses excited on the opposite side. The frequency spectrum of detected pulses ranged from 5 to 200 MHz.

Deformation inhomogeneity in roll drawing process

The deformation inhomogeneity of flat wires produced with roll drawing process is analyzed. The effect of main process parameters, i.e., initial wire diameter, forming roll dimension and thickness reduction on deformation inhomogeneity is established by means of experimental tests and a developed FE model. Vickers microhardness–strain relationship is developed for the analyzed material (low carbon steel AISI-1010) by correlating the microhardness measurements and effective strain fields as predicted by an axisymmetric numerical model of a compression test. A non-linear finite element model of roll drawing process is developed for a thorough understanding of process parameters effect on deformation inhomogeneity. Thus, in order to encompass the wide range of process conditions, an inhomogeneity index, calculated as the coefficient of variation of effective strain, is used. The numerical results showed that the inhomogeneity factor of flat wires produced with roll drawing is highly dependent on area reduction.