Continuous Wire Research Articles

Molecular Dynamics Investigation of Cl− and Water Transport through a Eukaryotic CLC Transporter

Early crystal structures of prokaryotic CLC proteins identified three Cl– binding sites: internal (Sint), central (Scen), and external (Sext). A conserved external GLU (GLUex) residue acts as a gate competing for Sext. Recently, the first crystal structure of a eukaryotic transporter, CmCLC, revealed that in this transporter GLUex competes instead for Scen. Here, we use molecular dynamics simulations to investigate Cl– transport through CmCLC. The gating and Cl–/H+ transport cycle are inferred through comparative molecular dynamics simulations with protonated and deprotonated GLUex in the presence/absence of external potentials. Adaptive biasing force calculations are employed to estimate the potential of mean force profiles associated with transport of a Cl– ion from Sext to Sint, depending on the Cl– occupancy of other sites. Our simulations demonstrate that protonation of GLUex is essential for Cl– transport from Sext to Scen. The Scen site may be occupied by two Cl– ions simultaneously due to a high energy barrier (∼8 Kcal/mol) for a single Cl– ion to translocate from Scen to Sint. Binding two Cl– ions to Scen induces a continuous water wire from Scen to the extracellular solution through the side chain of the GLUex gate. This may initiate deprotonation of GLUex, which then drives the two Cl– ions out of Scen toward the intracellular side via two putative Cl– transport paths. Finally, a conformational cycle is proposed that would account for the exchange stoichiometry.

Um programa de computador para simular alguns aspectos operacionais da soldagem MIG/MAG

A soldagem MIG/MAG e processos correlatos, que usam o arco e a alimentação contínua de arame, permanecem como os de maior importância industrial para a união de peças metálicas. Estes processos tendem a apresentar um elevado número de variáveis. A soldagem MIG/MAG é, ainda, sujeita a diferentes fenômenos que podem causar dificuldades durante a sua aplicação e, em particular, no planejamento e na definição das condições operacionais para uma dada aplicação. O presente trabalho descreve o desenvolvimento de um modelo para simular a variação de algumas variáveis do processo (como a corrente e tensão de soldagem e o comprimento do arco) e a sua implementação em um programa de computador. As equações básicas do modelo são apresentadas e discutidas com considerações sobre a sua aplicação. Resultados de testes experimentais para a determinação de alguns parâmetros fundamentais do modelo são também apresentados e discutidos. Simulações usando o programa desenvolvido são apresentadas juntamente e comparadas com testes reais de soldagem. Ferramentas do programa para simular mudanças nas condições operacionais de soldagem, no comportamento do arco elétrico e na operação da fonte de soldagem são apresentadas. Encaminhamentos baseados em abordagem teórica e empírica para algumas destas capacidades são apresentados.

Composite chiral metamaterials with negative refractive index and high values of the figure of merit

A composite chiral metamaterial (CCMM) is designed and studied both numerically and experimentally. The CCMM is constructed by the combination of a continuous metallic wires structure and a purely chiral metamaterial (CMM) that consists of conjugated Rosettes. For the CMM, only very small, useful bands of negative index can be obtained for circularly polarized waves. These bands are all above the chiral resonance frequencies because of the high value of the effective parameter of relative permittivity ε. After the addition of the continuous metallic wires, which provide negative permittivity, the high value of ε can be partially compensated. Thus, a negative index band for the left circularly polarized wave that is below the chiral resonance frequency is obtained for the CCMM. At the same time, a negative index band for the right circularly polarized wave that is above the chiral resonance frequency is also obtained. Furthermore, both negative index bands correspond to the transmission peaks and have high values of the figure of merit. Therefore, the CCMM design that is proposed here is more suitable than the CMM for the construction of chiral metamaterials with a negative index.

Preparation of Continuous Gold Nanowires by Electrospinning of High‐Concentration Aqueous Dispersions of Gold Nanoparticles

Gold nanowires are prepared by the electrospinning of highly concentrated aqueous dispersions of gold nanoparticles (AuNPs) in the presence of poly(vinyl alcohol) and subsequent annealing at higher temperatures. Continuous wires of sintered AuNPs are obtained as a result of this process. The Au wires are characterized by transmission electron microscopy, helium ion microscopy, optical microscopy, and X-ray diffractometry.

Tunable Dual-Band Negative Refractive Index Metamaterial Consisting of Ferrites and SRR-Wires

In this paper, we present a tunable dual-band negative refractive index metamaterial (NRIM), which composed of ferrite slabs, split ring resonators (SRR), and continuous wires. Numerical simulation shows that two pass-bands could be found in such structure, and the dual-band negative refractive indexes are demonstrated with the retrieved effective parameters based on the simulated scattering parameters. Taking advantage of the tunable permeability of ferrite slabs, we show these two negative refractive index passbands can be dynamically tunable by simply changing the magnetic bias.

Multifrequency Radiator With Spatial Diversity Based on Metasurfaces

A low-profile multifrequency antenna that radiates at a different half-space at each of its frequency bands has been designed, numerically evaluated, fabricated, and tested. The antenna consists of a U-slot dipole placed between two metasurfaces composed of grids of cut and continuous wires. The fabricated prototype radiates toward the upper half-space at the low-frequency band with 6.1 dBi gain (10 dB of front-to-back radiation ratio) and toward the lower half-space at the high-frequency band, with two peaks of 7.6 and 6.8 dBi gain (with 12.6 and 23.8 dB front-to-back radiation ratio, respectively). The antenna remains planar with a thickness of 0.15 at 9.3 GHz.

The Effect of Flux Core Arc Welding (FCAW) Processes On Different Parameters

Flux Core Arc Welding (FCAW) is an arc welding process that using continuous flux-cored filler wire. The flux is used as a welding protection from the atmosphere environment. This project is study about the effect of FCAW process on different parameters by using robotic welding with the variables in welding current, speed and arc voltage. The effects are on welding penetration, microstructural and hardness measurement. Mild steel with 6mm thickness is used in this study as a base metal. For all experiments, the welding currents were chosen are 90A, 150A and 210A and the arc voltage is 22V, 26V and 30V respectively. 20, 40 and 60cm/min were chosen for the welding speed. The effect will studied and measured on the penetration, microstructure and hardness for all specimens after FCAW process. From the study, the result shown increasing welding current will influenced the value depth of penetration increased. Other than that, the factors that can influence the value of depth of penetration are arc voltage and welding speed.

Study on Cooling Process of Hot Rolled Wire Rod with Dual Phase Microstructure

In the present paper effect of post deformation cooling rates on microstructure of ER70S-6 steel was investigated by using Gleeble1500 simulator. From the results, a controlling cooling process for obtaining dual phase (DP) microstructure was designed to produce hot rolled wire rod with a diameter of 6.5mm in a continuous no-twist and high-speed wire rolling mill, and the microstructures and the tensile properties of the wire rod were analyzed. The results showed that ER70S-6 steel deformed at 845°C and cooled at a rate of faster than 10°C/s had a DP microstructure with grain size of less than 8.3μm and martensitic volume fraction of 9-11%. The hot rolled wire rod cooled by blowing air had a DP microstructure with a grain size of 8.2μm and martensitic volume fraction of 11.5%. The present wire rod was superior to that of the same steel with ferrite plus pearlite microstructure in tensile properties, with yield strength level of 335-345MPa, ultimate tensile strength level of 600-620MPa, plastic elongation of 26.5-31.5% and strain hardening exponent of 0.221, respectively. ER70S-6 steel wire rod with DP microstructure showed promise of meeting the requirements for grade 8.8 fastener.,In the present paper steel wire rod with DP microstructure showed promise of meeting the requirements for grade 8.8 fastener.

Tunable dual-band ferrite-based metamaterials with dual negative refractions

We report on three types of tunable dual-band metamaterial with dual negative refraction in this paper. The three types of metamaterial are composed of ferrite slabs and three different metallic resonators, including split-ring resonators (SRR), Ω-like resonators, and short wire pairs. The ferrite slabs under an applied magnetic bias provide one magnetic resonance frequency band and the three metallic resonators provide another magnetic resonance frequency band, respectively. The continuous wires within the metamaterials provide the negative permittivity in a wide frequency band covering the two magnetic resonance bands. We give the design, analysis and numerical demonstrations of three such types of metamaterial in detail. The effective electromagnetic parameters obtained from the simulated S-parameters indicate that the three types of metamaterial indeed exhibit two negative refraction passbands and the two passbands can also be shifted by changing the magnetic bias. Our results open the way to fabricate tunable dual-band metamaterial cloaks, absorbers, and antennas.

Hydrocarbon–metal reactions during metal arc welding under oil (MAW-UO)

Metal arc welding under oil is a new, revolutionary process for the repairs of pipelines which should minimise the need of hot tapping repairs and the construction of bypass lines. The process uses an automated metal arc welding set-up with a continuous wire feed. This process was developed for the in situ internal repairs of in service cross-country pipelines, tanks and vessels by using a smart pig with a modified mechanical design that allows for joint preparation and welding. The unique characteristics found in the under oil arc are discussed in detail. The large range of temperatures that exists between the arc at the order of 10 000°C (18 000°F) and the surrounding oil (ambient) allows for complex reactions between the oil hydrocarbon chains and the steel weld metal. These reactions may considerably impact the weld microstructure. Details of the dissociation of hydrocarbon chains and ionisation of the resulting species must be known to better control the process. In addition, vaporisation of the oil will form oil vapour bubble to surround the welding arc. The oil vapour bubble will also be high in decomposed products that can significantly affect the weld metal composition. Gas chromatography–mass spectrometry was used to investigate the behaviour of a welding arc under oil and the carbon pick-up. Analyses were conducted on oil samples with different welding exposure times to validate the arc behaviour mechanistic model and the gas chromatography–mass spectrometry analysis results.

Study on corrosion behavior of continuous bulk metallic glass-coated steel wire composite

Zr41.2Ti13.8Cu12.5Ni10Be22.5 (atomic percent) (Vit1) Bulk metallic glass (BMG)-coated steel wire composite was produced by using continuous process. The existence of amorphous structure in the BMG coating was proved by differential scanning calorimeter (DSC) measurement and transmission electron microscope (TEM). The corrosion behaviors of the bare steel wire and the wire composite in 3.5 wt% NaCl solution corrosive media were investigated by immersion tests and electrochemical polarization measurements at room temperature. Scanning electron microscopy (SEM) was utilized to examine morphology of the corroded surface. By comparing the corrosion behaviors of the wire composite and the bare steel wire as well as the Vit1 BMGs reported in the literatures, the results of the present investigation reveal (1) it is important to choose sound technical parameters such as processing temperature to avoid the crystallization for the BMG coating of steel wire (2) the Vit1 BMG-coated steel wire composite has better corrosion resistance than the bare steel wire from perspective of either mass loss or polarization behavior (3) strong protective layers grow on the surface of the coated steel wire by anodization, of which the barrier effect to initiate pitting is slightly lower than that of the monolithic Vit1 BMG, but the general polarization behavior is quite similar to that of the monolithic Vit1 BMG.

Highly automated vine cutting transplanter based on DGNSS-RTK technology integrated with hydraulic devices

The aim of this paper is to propose an innovative system for a commercial transplanter that allows the automatic point-laying location of each vine cutting without any kind of preliminary field squaring. We modified a semi-mounted disk planting unit transplanter (Wagner Company) in order to realize the integral automation of the setting phase of a vineyard. The transplanter machine was originally equipped with a built-in laser (to maintain equal distance among the rows) and a continuous wire system (as a synchronization set). In the proposed system, the vine cutting location is calculated by a DGNSS-RTK system according to the project values, and the transplant operation was completely automated and carried out by electro-hydraulic components. The system was designed, developed, tested and patented by the Authors with the collaboration of Università degli Studi di Milano and of a private company (Arvatec s.r.l., Rescaldina – MI, Italy). In particular, the wire synchronization system was replaced by a hydraulic motor fixed to the frame and connected to the disk planting unit through the chain transmission. A specific software application, installed on an on-board automotive PC located in the tractor cabin, enables quick field-squaring and calculates the target setting point for each vine cutting (prescription map). The proposed system was tested in different topographic conditions with respect to the field slope, and the results were satisfying, both in terms of the precision and the orthogonality of the planting. From an operational point of view, the proposed system reduces labour requirements, as the ground worker responsible for managing the laser and the wire at the beginning of the row is no longer needed. Thus, the transplanting work rate is increased by 15% when compared with conventional solutions, whose controlling systems are based on a combination of laser tools and wire synchronisation systems.

Displacement across the Trecastagni Fault (Mt. Etna) and induced seismicity: the October 2009 to January 2010 episode

The Trecastagni Fault (TF) is a NNW-SSE tectonic structure inside Mt. Etna that is characterized by evident morphological scarps and normal and right-lateral type movements that directly affect roads and buildings. The TF has an important role in the instability that affects the south-eastern flank of Mt. Etna, and it represents part of the southern boundary of the unstable sector. Starting from 2005, the TF has been monitored using continuous wire extensometers and by carrying out periodic direct measurements across the northern and central sectors. From 2005 to September 2009, the measurements show that the TF has undergone continuous extension of about 2-3 mm/yr. During the October 2009 to January 2010 period, the creep rate of the TF reached up to 5.5 to 7.0 mm/yr, and this was accompanied by several shallow, low magnitude earthquakes that were felt by local people. This episode appears to be linked to the increase in the sliding velocity of the eastern flank that occurred during 2009.

Bend-imitating models of abruptly bent electron waveguides

The fundamentals of bend-imitating approach regarding the one-electron quantum mechanics in abruptly bent ideal electron waveguides are given. In general, the theory allows to model each particular circularlike bend of a continuous quantum wire as some effective multichannel scatterer being pointlike in longitudinal direction. Its scattering ability is determined by the bending angle, mean bending radius, lateral coordinate (or coordinates) in wire cross section, time (or electronic energy), and possibly by the applied magnetic field. In an equivalent formulation, the theory gives rise to rather simple matching rules for the electron wave function and its longitudinal derivative affecting only the straight parts of a wire and thereby permitting to bypass a detailed quantum mechanical consideration of elbow domains. The proposed technique is applicable for the analytical investigation of spectral and transport electronic properties related to the ideal abruptly bent 3D wirelike structures of fixed cross se...

Characterization and electromagnetic response of a ϕ-shaped metamaterial

In this paper we experimentally and numerically study the left-handed behavior in a biplanar metamaterial operating at microwave frequency. The metamaterial consists of ϕ-shaped metallic patterns on both sides of a dielectric spacer. The origin of negative refractive index is elucidated by performing the effective medium analysis. Additionally, the dependence of the left-handed transmission on geometric parameters, such as the periodicities, the shapes of metallic slabs and continuous wires, and the impact of spacer separation, is examined.

Miniaturized resonant inclusions as non-bianisotropic double negative metamaterials for normal incidence

Two novel resonators were devised which are amendments on commonly used S-shaped resonator and enable a great miniaturization rate. The symmetrical structure of these inclusions can avoid magnetoelectric coupling in the artificial constituents that preclude the bianisotropy. One of these metamaterials is an integration of continuous wire and an S-shaped-spiral. The other is a structure of SRRs and S-shape resonator with improved electromagnetic coupling and reduced electrical size. Both of them have wide negative refraction passband with low losses. The superior performances of these structures were investigated numerically and experimentally for only normal incidence case and tested through a proper comparison with the S-shaped resonator.

Invariant imbedding theory of charge pumping in quantum wires

We have developed a method to study the theory of charge pumping through a continuous quantum wire using the invariant imbedding approach. Using this method, the general properties of quantum charge pumping, with and without inclusion of many-body interactions are investigated. Using the invariant imbedding approach allows us to address directly the complex reflection (R) and transmission (T) matrices across the wire instead of considering the spectrum of the Schrodinger equation. Using the Kohn–Sham version of density functional theory (DFT), the many-body interactions in the quantum wire is investigated. We calculated the pumped current in those two cases. In the case of ignoring the many-body effects, the pumped current depends on the width of the driven potential barriers and in the case of nonequality of the width of barriers, our study predicts a nonzero charge pumping at the phase difference φ=0 even when the driving potentials are equal. In the second case, although the pumped current had sinusoidal dependence on φ but its value significantly decreased and we also observed nonzero pumping at φ=0 even when the driving potentials and their widths are equal, which is consistent with the recent experimental result.

Versatile Auxiliary Orthodontic Spring for Orthodontic Correction of Impacted Teeth

The ectopic eruption and impaction of permanent canine is a frequently encountered clinical problem. Lowest incidence of impacted canines 0.27% reported in literature relates to Japanese sample population. In Americans and Israeli, it is 1.5% while the highest incidence of 7.9% was reported among Iceland population. Maxillary canine, since last in eruption sequence (except third molars), is most prevalent to be malpositioned due to tooth size arch length discrepancy (TSALD). Auxiliary springs have been used in orthodontics since long for the correction of impacted or unerupted canines or adjacent teeth. Cantilever springs are preferred than the continuous wires as placement of continuous flexible wires for correction of these single tooth malocclusions produces adverse effects on adjacent teeth, i.e. flattening of the arch and/or openbite in that region which eventually require more time for correction. In Begg’s light force appliance, various methods have been used, including the use of light wire springs, springs soldered to the heavy labial or palatal base wire and mousetrap loops bent in the archwires. With the use of these methods orthodontist had no precise control of magnitude and direction of force. Ballista spring, a unilateral spring made up of round wire and is tied into one of the molar tube, lacks the versatility in its use. Seong-Sang used auxiliary wire comprising 0.014 inch Australian Willcock wire. 1n 1995, Kornhauser et al used labial spring auxiliary. Orton in 1995 used a combination of the lower removable appliance and gold chain since this can be readily fabricated. Magnets are also utilized for the correction of impacted canines. Bowman and Carano introduced the Kilroy spring in 2003. Auxiliaries used previously lacked the versatility of their use with different fixed appliances, such as round and rectangular molar tubes and were not applicable for different malpositions of the canine or adjacent teeth. Their uses were restricted to specific conditions. Present article describes the fabrication of a self-stabilizing, self-locking, versatile auxiliary orthodontic spring (VAOS).

Numerical study of effect of geometrical parameters on the passband of left-hand material

We systematically study the transmission property of metallic short-slab pair and continuous wire structure metamaterial and its dependence on the system geometrical parameters in the infrared frequency regime, using the transfer-matrix method and the commercial code, CST Microwave Studio. It is found that the passband is sensitive to the length and the thickness of the continuous wire. As the length or thickness increases, the passband is slightly extended to a higher frequency. It is also found that the dependence of the passband on the material of dielectric layer.

Thermoplastic Wire Drawing from Bulk Metallic Glass

ABSTRACTThe low loss coefficient and high elastic energy storage of amorphous metals may provide novel opportunities in the design of stringed musical instruments. To produce prototypes for metallic glass music wire, bulk metallic glass pre-forms were reheated into the supercooled liquid region and stretched into wires. Investigations of these wires’ geometrical, mechanical, and physical properties are reported. The process is relatively simple and could be practical for producing continuous wire. A theoretical analysis shows the importance of the interaction between heating power input, radiative and convective cooling, and area reduction in determining the wire’s final properties.