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Background: CircRNA plays a regulatory role in multiple life processes. Circ_0122396 could participate in the regulation of age-related cataract (ARC) progression. However, the precise molecular mechanisms of circ_0122396 In ARC remain enigmatic. Methods: Circ_0122396, microRNA (miR)-23a-3p, and matrix metalloprotease (MMP)-16 (MMP16) expression levels were detected via quantitative real-time polymerase chain reaction. Western blot was used to detect the levels of MMP16 and apoptosis-related proteins. Cell counting kit-8 analysis and 5-ethynyl-2'-deoxyuridine assay were used to assess human lens epithelial cells (HLECs) proliferation. Flow cytometry was performed to determine cell apoptosis. Levels of malondialdehyde (MDA) and glutathione peroxidase (GSH-PX) were measured using commercial kits. Luciferase reporter assay, RNA immunoprecipitation (RIP) assay, and RNA pull-down assay were used to examine the interaction among circ_0122396, miR-23a-3p, and MMP16. Results: Circ_0122396 and MMP16 were down-regulated while miR-23a-3p was up-regulated in ARC. H2O2 constrained proliferation and GSH-PX level, promotes apoptosis and MDA level in HLECs, and overexpression of circ_0122396 attenuated these effects. miR-23a-3p was a direct target of circ_0122396, and MMP16 was a direct target of miR-23a-3p. The effect of circ_0122396 overexpression on H2O2-induced HLECs was reversed by miR-23a-3p, and MMP16 elevation overturned the impacts of miR-23a-3p in H2O2-induced HLECs. Conclusions: Circ_0122396 may regulate the progression of ARC via the miR-23a-3p/MMP16 pathway in H2O2-stimulated HLECs, which may serve as a potentially valuable biomarker and novel therapeutic target for ARC. [ABSTRACT FROM AUTHOR]

Devonian successions in the Calliope and Yarrol provinces of the northern New England Orogen in central to northern Queensland have a lithological assemblage and depositional environments indicative of a close association with a subduction-related volcanic arc. These rocks have been interpreted as related to island arc and backarc settings based on geochemical characteristics of magmatic rocks. We present new detrital zircon ages from the Devonian to lower Carboniferous successions of the Calliope and Yarrol province successions. Most samples have no or relatively few zircon grains extracted except for samples of quartz-rich sandstone in the Middle Devonian Erebus beds of Hunter Island, located 160 km north-northwest of Rockhampton and another sample in the Rockhampton district. The samples with abundant zircon, and some with less common zircon, have prominent peaks of mid Cambrian to Ordovician ages and are consistent with derivation from the northern Thomson Orogen where igneous rocks of this age are documented in the Charters Towers Province. These data indicate a connection between the Devonian arc-flank deposits of the northern New England Orogen and the Thomson Orogen, which had previously been well established for Carboniferous deep-marine sandstones of the subduction complex (e.g. Shoalwater Formation). These results favour an east-facing continental margin arc setting in the Devonian contra to intra-oceanic island arc settings previously proposed. Detrital zircon age spectra from sampled early Carboniferous units of northern New England Orogen association indicate a pulse of felsic magmatism of that age. KEY POINTS: Devonian quartz-rich sandstones from the northern New England Orogen have abundant detrital zircon ages of mid Cambrian to Ordovician indicating a provenance connection with the Charters Towers Province of the northern Thomson Orogen. These results confirm a provenance linkage to Gondwana and imply that the Devonian tectonic setting was a continental margin arc and associated forearc basinal infill. Geochemical comparisons suggesting an island arc setting have overly influenced previous tectonic interpretations. [ABSTRACT FROM AUTHOR]

This study investigated if acylated ghrelin (AG) could inhibit myocardial infarction (MI)-induced apoptosis in the left ventricles (LV) of male rats and tested if this protection involves modulating ARC anti-apoptotic protein. Rats (n = 12/group) were assigned as a sham-operated, a sham + AG (100 µg/kg, 2x/d, S.C.), MI, and MI + AG. With no antioxidant activity or expression of FAS, AG inhibited caspase-3, 8, and 9 and decreased cytosolic/mitochondrial levels of cytochrome-c, Bax, Bad, and Bad-BCL-2 complex in the LVs of the sham-operated and MI-treated rats. Concomitantly, AG preserved the mitochondria structure, decreased mtPTP, and enhanced state-3 respiration in the LVs of both treated groups. These effects were associated with increased mitochondrial levels of ARC and a reduction in the activity of calcineurin. Overall, AG suppresses MI-induced ventricular apoptosis by inhibition of calcineurin, activation of ARC, and preserving mitochondria integrity. [ABSTRACT FROM AUTHOR]

The effect of polarity and shielding gases on the droplet transfer behavior and formation trend of cable-type welding wire gas metal arc welding was studied under the same welding parameters. An acquisition system was used to observe welding parameters, droplet transfer and arc behavior. The results showed that the arc shapes with different polarities under the same shielding gas were different. The arc length and width in direct current electrode positive (DCEP) mode were smaller than those in direct current electrode negative (DCEN) mode. For the same polarity and different shielding gases, with increasing CO2 gas content, the arc length and width gradually decreased. In DCEP mode, droplet transfer was characterized by globular and projected droplet transfer modes. The droplet transfer modes with different polarities differed under different shielding gases. The droplet transfer mode was basically the same for the same polarity. With increasing CO2 content, the weld bead formation gradually improved. [ABSTRACT FROM AUTHOR]

In this work, 4,5-dinitro-1-methylimidazole (4,5-MDNI) was synthesized and characterized. The thermal decomposition performance of 4,5-MDNI was studied by accelerating rate calorimeter (ARC) under adiabatic conditions, and the thermal decomposition reaction order, possible thermal decomposition kinetic model, and self-accelerating decomposition temperature were calculated. The stability of 4,5-MDNI and its compatibility with high-energy explosives (RDX, HMX, CL-20) were studied by differential scanning calorimetry (DSC). The test results show that 4,5-MDNI has a good stability, poor compatibility with HMX, and basically incompatibility with RDX or CL-20. [ABSTRACT FROM AUTHOR]

This experimental investigation introduced the gas metal arc welding-based additive manufacturing to deposit single-layered beads of ER70S–6 and 316 L stainless steel (SS). Different experimental conditions are generated through response surface methodology for illustrating the effect of wire electrode material and deposition parameters on bead characteristics. From parametric analysis, wire feed speed and torch speed are found to be the most controlling factors for bead width, height, deposition area, penetration depth, dilution, and contact angle. Deposition with 316 L SS wire exhibits minimal bead characteristic features than ER70S–6 because of high electrical resistivity that restricts excessive flow of arc current (low thermal energy development) and maintains the molten pool stability. Microstructural transformation from the continuous nature of δ-ferrite into an isolated core-like structure indicates the heat input's role over grain refinement. X-ray diffraction depicts α-Fe and ϒ-austenite phases (with δ-Fe) in ER70S–6 and 316 L SS deposits. [ABSTRACT FROM AUTHOR]

Twin tungsten electrode – wire electrode indirect arc welding (TTW IAW) was a novel welding method. In this paper, the wettability and spreading of weld bead of TTW IAW were investigated by comparing with single tungsten electrode – wire electrode indirect arc welding (STW IAW). Results showed that compared to STW IAW, TTW IAW possessed larger arc width and greater arc heat distribution range with smaller variation gradient, due to the lower velocity of charged particles toward the arc center, caused by the smaller electromagnetic force acting on the arc plasma. So did the temperature distribution of weld pool of TTW IAW. Moreover, the process stability of TTW IAW was better. Besides, at the molten pool front, the transverse convection of the melted metal of TTW IAW was adequate, because of the superior wettability and long flow duration of the melted metal; at the molten pool rear, the inward convection of the melted metal of TTW IAW was weak mainly owing to the low Marangoni force. Therefore, the weld bead width of TTW IAW increased by about 25.0% and the wetting angle of the weld bead decreased by about 25.7% compared to STW IAW, which indicated that the weld bead spreading of TTW IAW was better. [ABSTRACT FROM AUTHOR]

The single-phase induction motors (SPIMs) are predominantly used in the wider range of application developments. However, these motors have comparatively lower efficiency. Motors such as permanent magnet synchronous motor (PMSM), synchronous reluctance motor (SynRM), or switched reluctance motor are energy efficient. Although these motors posses high efficiency, the application cost becomes a significant concern. To cause the compatible performance of economical and conventional SPIM in terms of efficiency, lower temperature rise, weight reduction, and increased speed, this work addresses the conversion of SPIM into line-start SynRM (LS-SynRM). The required necessary modifications are analyzed using FEM. The design methodology is suggested for a typical 0.5HP SPIM that is tested in terms of rotor constructive parameters. The parametric sensitivity analysis is carried out using Ansys Maxwell FEM software. The rotor parameters such as cutout dimensions, type of barrier, their positions and widths, bridge thickness, pole arc to pole pitch ratios, and the end ring configurations are considered for the analysis. It has been determined that the efficiency is largely affected by the barrier positions and its width, and an improvement of two percent has been noted. However, the efficiency of LS-SynRM is also a function of bridge thickness, with higher values inferior is the efficiency. [ABSTRACT FROM AUTHOR]

In this paper, 1,2,4-triazolium 2,4,5-trinitroimidazolate (2), 3-amino-1,2,4-triazolium 2,4,5-trinitroimidazolate (3) and 4-amino-1,2,4-triazolium 2,4,5-trinitroimidazolate (4) were synthesized based on the method of acid-base neutralization and precipitation, which is a simple method compared with the method in Gao's literature. These compounds were characterized by FT-IR, NMR, elemental analysis. The structure of (2) was further confirmed by single-crystal X-ray diffraction. Thermal decomposition performances of (2)-(4) were tested using differential scanning calorimetry (DSC) and accelerating rate calorimeter (ARC). The DSC curves of (2)-(4) show that they all have good thermal stability and the order of thermal stability is (4) > (2) > (3). ARC test data calculation results show that the thermal stability of (2)-(4) is (3) > (2) > (4). The test results show that the thermal stability of compounds (2)-(4) under non-adiabatic and adiabatic conditions was quite different. The storage temperature of (2), (3) and (4) does not exceed 420.93 K, 435.78 K, and 393.69 K, respectively, and they will not undergo self-accelerating decomposition. [ABSTRACT FROM AUTHOR]

The purpose of the method of AC/DC mixed gas tungsten arc welding (GTAW) is to improve the welding efficiency of aluminum alloy AC-GTAW. It is expected to make a great change in the aluminum alloy manufacturing industries. The feature of AC/DC mixed GTAW includes two parts, AC mode and DC mode, during the welding process. A comparison study between the AC/DC mixed GTAW and AC-GTAW is carried out by analyzing the arc characteristics and weld formation. The results showed that the uniformly distributed AC and DC signals were obtained in the AC/DC mixed GTAW. The front width and back reinforcement of the weld bead in the AC GTAW and the AC/DC mixed GTAW increased first and then decreased with increasing frequency. The geometrical parameters of the weld cross-section in the AC/DC mixed GTAW was increased, when the same frequency was used. For example, the frequency of 30 Hz was employed, the front width of the weld bead in the AC/DC mixed GTAW was increased to 0.3 mm compared with that of the AC-GTAW. The AC/DC mixed GTAW has a greater effective heat input compared with the AC GTAW due to introduction of the DC mode. [ABSTRACT FROM AUTHOR]

A unique methodology has been developed with the compilation of two magnets to produce the double axial magnetic field, and the effect on the arc shape and the bead characteristics in the gas tungsten arc welding (GTAW) process have been investigated. The load-carrying capacity of the joint depends upon the bead geometry. The developed methodology is capable of altering the arc shape and consequently the bead geometry of weld as per the requirement. Experimental results show that the double axial magnetic field changes the arc shape from a conical to constricted conical. It is further observed that magnetic configurations North-South-South-North (N-S-S-N) and Zero-Zero-South-North (0-0-S-N) provided better results than other configurations. The North-South-South-North (N-S-S-N) configuration produced a minimum penetration (0.98 mm) and a maximum shape factor (7.81), along with good appearance of weld beads. This configuration is suitable for cladding and hardfacing applications. The increased penetration (3.03 mm) was achieved with the Zero-Zero-South-North (0-0-S-N) configuration compared with conventional welding (2.20 mm). Similarly, this configuration yielded a higher bead width (8.13 mm) than conventional welding (5.90 mm). This configuration is suggested for the single-pass welding operation. [ABSTRACT FROM AUTHOR]

Bypass coupling triple-wire gas indirect arc welding (TW-GIA) has been proposed to control the heat input of base metal and consequently improve the weld forming as per the requirement. The influence of the bypass current on arc behavior, welding stability, and weld forming have been investigated. Results showed that the wetting angle and reinforcement reduced gradually, and the weld bead penetration increased with the bypass current increase. The reason was that the workpiece heating mode was changed due to the bypass circuit coupling. It was observed that the heat source was composed of two indirect arcs and two direct arcs, and they were in a coupling state. When the bypass current was 280 A, the electrical parameters of arc fluctuations were at a maximum, and the coupled arc state was not conducive to obtain a stable welding process. Compared to the lack of sidewall fusion and incomplete joint penetration defects of the weld with TW-GIA, the good butt joint of 12 mm thickness steel plates was successfully obtained with bypass coupling TW-GIA under the same energy consumption. [ABSTRACT FROM AUTHOR]

Arc machining is suitable for efficiently processing typical difficult-to-cut material Ti6Al4V. Traditional arc sinking machining commonly uses water-based dielectric because of its safety and good cooling capacity. However, water-based dielectric generally has high conductivity that causes frequent short circuits and strong electrolytic reactions during machining, thereby reducing machining stability and deteriorating machining performance. This paper proposes a novel high-efficient compound sinking machining that combines arc machining with electrical discharge machining (EDM). The dielectric is formed by dispersing oxygen into deionized water, thus reducing the shortcomings of traditional water-based dielectric and introducing the advantages of gas-based one. The feasibility of the proposed method is systematically studied compared to the method that uses deionized water. Influences of oxygen pressure, pulse duration, and peak current are investigated. Characteristics of surface topography and recast layer are also studied. Results suggest that the properties of dielectric improve, and the machining stability and machining intensity increase with the assistance of oxygen. Therefore, compared with using deionized water, the proposed method shows better processing characteristics, including larger material removal rate (MRR), smaller relative electrode wear rate (REWR), and thinner recast layers. The proposed method is promising to process Ti6Al4V due to its high efficiency and environment-friendly properties. [ABSTRACT FROM AUTHOR]

As a high-energy insensitive explosive which is expected to replace 2,4,6-trinitrotoluene (TNT), it is necessary to evaluate the thermal risk of 2,4-dinitroanisole (DNAN). In this article, the thermal performance of DNAN was tested using differential scanning calorimeter (DSC) and accelerating rate calorimeter (ARC). According to the test results, the decomposition activation energy (E), the pre-exponential constant (A), activation entropy (ΔS≠), activation enthalpy (ΔH≠), activation Gibbs free energy (ΔG≠) at TP0 of the reaction and the critical temperature of thermal explosion (Tb) were obtained. The kinetic model under adiabatic conditions was established. The thermal hazard assessment of DNAN was carried out according to the thermodynamic parameters, and the assessment results are of great significance to the application of DNAN. [ABSTRACT FROM AUTHOR]

Inspired by a recent paper by Wares, we discuss an extension of another well-known geometric problem involving arcs which, since the solution is computer-assisted, could be a source of a mini-project for an introductory course on a computer algebra system. [ABSTRACT FROM AUTHOR]

The study sought to estimate the genetic gains and associated monetary value contributed by the TGCD programme of the Agricultural Research Council (ARC). The Just-Pope production function and cost benefit analysis (benefit cost ratio – BCR, and modified internal rate of return – MIRR) were employed to analyze the administrative programme costs and industry yield data for the ARC's cultivars. The results revealed an average annual yield gain of 0.21 t/ha for the period from 1965 to 2014, and a BCR of 4.85. An MIRR of 18% was also revealed. This means that for every rand invested in the programme, R4.85 is realized and the high MIRR further confirms the worthiness of these investments. Thus, these results are useful as evidence for the missing information on the effectiveness and efficiency of public funds expended in table grapes research and as motivation for increased funding, as well as for participation by other industry stakeholders. [ABSTRACT FROM AUTHOR]

Circular_0122396 (circ_0122396) has been reported to be downregulated in age-related cataract (ARC); however, the underlying mechanism remains unknown. The study aimed to reveal the role of circ_0122396 in ARC progression and underneath mechanism. Hydrogen peroxide (H2O2) was employed to induce lens epithelial cells (SRA01/04) injury. The RNA expression of circ_0122396, microRNA-15a-5p (miR-15a-5p) and fibroblast growth factor 1 (FGF1) was detected by quantitative real-time polymerase chain reaction. Protein expression was checked by western blot. Cell viability, proliferation and apoptosis were investigated by 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, 5-Ethynyl-29-deoxyuridine and flow cytometry analysis, respectively. Oxidative stress was evaluated by superoxide dismutase and catalase activity assay kits and lipid peroxidation malondialdehyde assay kit. Online databases and mechanism assays were used to predict and identify the relationship between miR-15a-5p and circ_0122396 or FGF1. Circ_0122396 and FGF1 expression were significantly downregulated, but miR-15a-5p expression was upregulated in ARC tissues or/and H2O2-treated SRA01/04 cells in comparison with control groups. H2O2 treatment repressed cell proliferation and induced cell apoptosis and oxidative stress, which was attenuated after circ_0122396 overexpression. MiR-15a-5p, a target mRNA of circ_0122396, was found to participate in H2O2-triggered cell damage by interacting with circ_0122396. Additionally, FGF1 silencing attenuated miR-15a-5p inhibitors-mediated action. Importantly, circ_0122396 regulated FGF1 expression by interaction with miR-15a-5p in H2O2-treated SRA01/04 cells. Circ_0122396 ameliorated H2O2-triggered cell injury by inducing FGF1 through sponging miR-15a-5p, providing a potential target for ARC therapy. [ABSTRACT FROM AUTHOR]

The present study deals with a new technique for controlling the weld-induced distortion. This developed technique involves in-situ preheating of welding filler wire before it emerges from the contact tube. Welding filler wire preheating was carried out using an external constant current power source and a specially designed welding torch. Weld beads were deposited on 3.0 mm low carbon steel sheet using a bead on plate technique with different preheat values of welding filler wire by the submerged arc welding process. Electrical signals were recorded to analyze the effect of welding filler wire preheating on arc characteristics. Probability density distribution (PDD) curves from electrical signals indicate that with the rise in preheat value, welding current decreases and results in stable arc characteristics. An increase in preheat value also reduces the longitudinal bending distortion of the sheet. The maximum reduction in the longitudinal bending distortion of the sheet (~53%) was obtained at the maximum preheat value of 200 Ampere. [ABSTRACT FROM AUTHOR]

The results of experimental studies of some features of non-consumable electrode welding in argon steel 12X18H10T with increased speed are presented. The possibility of improving the quality of formation and resistance of seams against the formation of hot cracks by exposing the arc and metal of the weld pool by controlling the magnetic field of the current flowing through the contact conductor located above the tail section of the weld pool, perpendicular to the electrode is shown. [ABSTRACT FROM AUTHOR]

Within this study, the potential of 3D Plasma Metal Deposition (3DPMD) for the additive manufacturing of multi-material metallic parts in layerwise design is presented. For this purpose, a demonstrator geometry with a step-wise increase of the tungsten carbide content in a Ti6Al4V matrix was fabricated. The build cycle itself, the component shape and the microstructure were investigated. The analysis of the macroscopic properties was performed by optical microscopy and scanning electron microscopy. In summary, 3DPMD offers the possibility to produce AM parts at high build rates and increased material flexibility. The analysis of the morphology and the macroscopic investigations shows a homogenous structure without defects. The carbide content of the manufactured components increases continuously from 0 to 12 vol.% but deviates from the aimed carbide content. Using automated CAM routines, it is possible to generate metallic multi-material structures using welding robots directly from the CAD drawings. [ABSTRACT FROM AUTHOR]

The effect of laser, Hybrid Laser-Tungsten inert gas (HLT) and Hybrid Laser-Metal inert gas (HLM) welding processes on the microstructure and mechanical properties of 5.6 mm thick 316L(N) stainless steel weld joints have been studied. The differences in weld metal microstructure and mechanical properties of the weld joints were evaluated and discussed. Weld bead geometry, ferrite number (FN), solidification mode, secondary dendrite arm spacing, hardness and tensile properties are compared. Laser weld joint showed narrow weld bead profile and a higher cooling rate than the hybrid laser arc weld joints and the weld metal manifested austenitic solidification mode. HLT weld displayed coarser weld metal microstructure due to higher heat input and austenitic ferritic solidification mode. HLM process possesses moderate heat input and cooling rate. The HLM weld metal exhibited ferritic austenitic solidification mode and 2.5 FN. The hardness of weld metal was higher in hybrid welding processes due to the higher ferrite content. HLM weld joint has higher yield strength, ultimate tensile strength and ductility compared to that of the other weld joints. HLM welding process also permits higher gap tolerance with filler metal addition and is recommended for welding of type 316L(N) stainless steel. [ABSTRACT FROM AUTHOR]

The spiral structure of seven-wire is the fundamental cause of arc rotation. The arc rotation frequency decreases with the radius of twisting circle and the helix angle, and increases with the welding current. The arc presents the reciprocating rotating upward motion when welding torch oscillates along the thickness of the plate. The sidewall penetration along the thickness direction of plates is approximately the same. The rotating arc promotes the stirring of melting metal, and the stirring effect intensifies the flow of melting metal and accelerates the heat transfer from the molten pool to the sidewall, which has a positive effect on increasing the penetration of sidewall and refining the grains of weld seams. [ABSTRACT FROM AUTHOR]

Arc additive manufacturing based on gas metal arc welding (GMAW) can decrease the cost and increase the efficiency of manufacturing large-sized components. In this paper, a double-arc additive manufacturing process for stainless steel 316L (SS316L) based on GMAW that does not use more power than the single-arc process is proposed. In addition, this study compared single- and double-arc additive manufacturing processes by analyzing the morphology, microstructure, and mechanical properties. The results indicate that with the same power, the deposition rate of the double-arc process was 1.25 times higher than that of the single-arc process. Further, the increased number of welding wires and the induced stirring of the molten pool produced finer grains. In addition, the average Vickers hardness and tensile strength of the double-arc sample were 0.6% and 3.5% higher than those of the single-arc samples, respectively, while the elongation was 0.34% lower, and the tensile properties had a similarity of over 90% with those of the SS316L wire. [ABSTRACT FROM AUTHOR]

A gas discharge lamp is a device, which operates as a light source by producing electrical discharge in ionized gaseous medium. Discharge lamps are commonly used in the market and according to their physical properties they can be mainly classified in three different categories: high pressure, low pressure and high-intensity lamps. Ionized gases have tendency to produce ongoing discharges and finally electrical arcs, which exhibit memristor characteristics proposed by Leon Chua. This paper introduces a novel fully floating memristor circuit emulator with tunable threshold characteristics which mimic discharge lamp characteristics. In order to investigate discharge lamp characteristics a test set-up is designed and commercially available discharge lamps are tested. The proposed memristor circuit displays distinctive characteristics in contrast to well-known smooth switching memristor characteristics in terms of hard switching capability. Proposed memristor has unique switching behavior and fully capable of modeling discharge lamps since it satisfies required zero-crossing, pinched hysteresis and frequency dependent characteristics of the discharge lamps. The comparisons of the current-voltage characteristics for both memristor and discharge lamps are supplied and investigated. [ABSTRACT FROM AUTHOR]

Arc discharge machining was an efficient method in machining difficult-to-cut materials. However, there was a serious overcutting phenomenon during machining, causing serious machining errors. In order to improve the machining accuracy, this paper presented a novel kind of arc discharge milling technology, which was based on the arc driving mechanism using the controllable non-uniform flow field around the tubular electrode. The control system changed the distribution of the non-uniform flow field in real time according to the machining path, driving the arc to extend in a controlled direction and reducing the repeated erosion of the specific machining surface. Compared with the annular flow field, the non-uniform flow field could reduce the overcutting by 52.15%, while obtaining similar relative electrode wear ratio (REWR) and material removal rate (MRR). The effects of non-uniform flow field, peak current of pulse generator, and pulse width on machining accuracy, REWR, and MRR were investigated. The result shows that the non-uniform flow field can significantly improve the accuracy of arc discharge machining. [ABSTRACT FROM AUTHOR]

Electric arc sweep machining is a thermal process derived from blasting erosion arc machining specialized for high efficient open channel machining. In this technology, high pressure inner flushing undertakes a critical role in plasma arc control and evacuating debris from craters. Hence, to find the best tool design procedure, contour of effective fluid velocity distribution in the gap distance is simulated for different flushing hole patterns and then, experiment conducted to measure machining performance. Empirical findings demonstrated higher material removal rate relative to bigger effective flushing region. Based on this, principle of tool design optimization is introduced when d = 3 mm is the best flushing hole diameter arranged along the centerline and holes with d = 2 mm are located symmetrically adjacent to the centerline. [ABSTRACT FROM AUTHOR]

Wire and arc additive manufacturing (WAAM) has advantages of high efficiency and low cost. However, different welding current processes lead to different heat input and repeated heating treatment during the deposition process, which has an influence on the forming and performance. In this study, 30 layers of reciprocating depositions for 316L stainless steel were carried out by speed cold and speed arc welding processes, and the morphology, effective deposition rate per power, microstructure, and properties of depositions were compared. The outcomes indicated that different welding current processes make different shaping appearances, and the effective deposition rate per power of speed cold welding is 15.2% higher than that of speed arc welding. The microstructures of depositions are columnar crystals; however, the higher power of speed arc welding leads to the coarse structure, and the enhanced thermal cycle and preheating effect produce a uniform hardness and 4.9% higher tensile strength, but lower toughness than those of speed cold welding. Due to the direction of deposition, the tensile strength of depositions by two processes has obvious anisotropy that can reach to 8.18% and 13.3%, respectively. [ABSTRACT FROM AUTHOR]

The influence of researches results of the welding circuit magnetic field on the seam formation at welding steel 12X18H10T by weight with a non-consumable electrode in argon are presented. The possibility of retaining the molten metal of the weld pool by the magnetic field of the current flowing along a rectilinear conductor located in the plane of the welded joint above the tail of the weld pool is shown. It is established that the efficiency of holding the molten metal of the weld pool is largely determined by the location of the current lead, the speed and rigidity of the welding mode. [ABSTRACT FROM AUTHOR]

Cultivar choice is an important production decision by which producers aim to achieve highest returns with the lowest risk, for yield optimisation. Cultivar testing through evaluation trials provides information on selected cultivar characteristics and performance under different conditions, which farmers use to minimise risk elements associated with limited cultivar performance information. In South Africa, the Agricultural Research Council conducts national wheat cultivar trials funded from public resources. However, the economic value of the programme remains unknown. The study estimates aggregate economic benefits associated with the programme using data from 1998 to 2016 and attribution methodologies used in other studies, modified within the context of this study. Yield gain estimates are used as indicators to estimate the contribution of seed choice to yield growth at selected levels of the assumed plausible yield gains. Overall, the study estimates that 0.04 ton (40 kg) per hectare of extra wheat yields accrued to wheat producers as a result of cultivar trials in the period under consideration. The net present value was found to be R173 million (in 2016 prices), while South Africa received R4.33 for every Rand invested into the programme. An estimated MIRR of 7 per cent suggests that investments into the programme have been a worthwhile use of public funds. The observed yield gains and favourable efficiency measures motivate continuation of the programme. [ABSTRACT FROM AUTHOR]

Load-carrying capacity of weld joints could be identified by its shape and size where weld bead geometry and shape relationship parameters are of utmost importance. Heat input and preheating temperature together can control the cooling time of weld, which in turn determines the weld microstructure and its mechanical properties. To control the shape and geometry of weld bead, it is necessary to understand its relationship with cooling time. In present work, preheating temperature is used as process variable along with heat input varying parameters for understanding their effects on weld bead geometry and shape relationship parameters using submerged arc welding process on high-strength low alloy pipeline steel. The experimental investigation was then analyzed by using the mathematical modeling in context with response surface methodology. The mathematical model predicts the influential dependency of cooling time on the preheating temperature than the other weld process parameters. The associated effects in relation to the process parameters have been discussed and analyzed in the present study. [ABSTRACT FROM AUTHOR]

In this study, we have explored the influence of newly developed tri-component oxide flux (Cr2O3, FeO, and MoO3) on weldability, bead geometry, weld pool temperature variation, and mechanical strength of Inconel 718 welded joints. Moreover, the influence of used flux on weld pool, the surface morphology of electrode and penetration capability of tungsten inert gas (TIG) welding on Inconel 718 plates have been well elucidated. Results indicate that the flux mixture significantly increases the penetration depth as well as aspect ratio almost 200% as compared to conventional TIG welding. The arc constriction caused by newly developed oxide flux upsurges the heat density and the weld pool temperature of joints. The alloying effect caused by entrapped oxide particles greatly improves the hardness as well as the tensile strength of joints. The reported reinforcement in the welding performance may increase potential utility of the developed methods for real-world applications. [ABSTRACT FROM AUTHOR]

Prostate cancer-associated ncRNA transcript 6 (PCAT6) is a long intergenic noncoding RNA that is involved in the progression of prostate and lung cancer, acting as a potential diagnostic and prognostic biomarker in nonsmall cell lung cancer. However, little is known about PCAT6 expression and its clinical significance in colon cancer. Here, we aimed to investigate the clinical significance of PCAT6 in colon cancer and its underlying mechanism. The expression of PCAT6 was analyzed in colon cancer tissues using public databases, and a series of in vitro and in vivo experiments was performed to investigate the biological functions of PCAT6 in colon cancer cells and the underlying mechanisms. Our results demonstrated that PCAT6 was upregulated in colon cancer tissues compared with that in noncancerous tissues, correlating with poorer clinical stages and a worse survival status. In vitro and in vivo experiments illustrated PCAT6 promoted cell growth and inhibited cell apoptosis in colon cancer. Mechanistically, PCAT6 enhanced the coenrichment of EZH2 and H3K4me3 at the apoptosis repressor with caspase recruitment domain (ARC) genomic region, promoting the transcriptional activity of ARC. Our data highlighted that PCAT6 acts as a key activator of ARC expression by forming a complex with EZH2, inhibiting cell apoptosis and contributing to colon cancer progression. These findings elucidated that PCAT6 may be a novel prognostic predictor and therapeutic target of colon cancer. [ABSTRACT FROM AUTHOR]

Thermal plasma method has been used to process mild steel scrap for nanopowder synthesis by changing the operating current. The phase analysis of the product nanopowders was studied by X-ray diffraction and the chemical composition was studied by energy dispersive spectroscopy. The morphology, particle size and particle size distribution of the samples were investigated by field emission scanning electron microscope. In addition to the above, the magnetic properties of the samples were investigated by superconducting quantum interface device magnetometer and high temperature vibrating sample magnetometer (HTVSM). From this study, the results indicate that the processed nanopowders were magnetite and exhibit spherical morphology. The magnetic properties, such as, saturation magnetization (MS), coercivity (HC), and Curie temperature (Tc) were estimated. The M-H loops exhibited soft magnetism and samples corresponding to 60 and 70A showed the highest MS and HC, respectively. The Curie temperature was determined for the sample corresponding to 60A using HTVSM as 852 and 840 K from the heating and cooling curves, respectively. The outcome of the results suggests that thermal plasma is a contaminant-free process and is suitable for processing metal scrap. [ABSTRACT FROM AUTHOR]

In this article, effects of advanced submerged arc welding process parameters on weld bead geometry have been investigated. A novel water-cooled torch has been developed which allow a use of higher preheat current values for a continuous advanced submerged arc welding (ASAW) operation. Weld beads have been deposited on AISI 1023 steel plates by varying open circuit voltage, wire feed rate, welding speed, nozzle to plate distance, and preheat current as per central composite design. The relationships between welding parameters and weldment characteristics namely bead width, penetration, reinforcement, and dilution have been developed using multiple linear regression. The effects of individual process parameters and their interactions on response parameters were examined. Finally, single and multiobjective optimization of process parameters were performed using desirability approach and Jaya algorithm. The results reveal that a smaller bead width and lower dilution can be achieved with the developed torch by allowing the use of higher preheat current values. [ABSTRACT FROM PUBLISHER]

In gas metal arc welding, arc ignition significantly influences arc stability, droplet transfer, and the quality of welded joints. Cable-type welding wire (CWW) CO2welding is an innovative welding method. This paper analyzes the arc ignition procedure for this type of welding based on experiments with three different wire end conditions: an unsmooth wire end, a smooth wire end, and a preheated smooth wire end. Smaller contact areas between the CWW and the workpiece led to higher arc ignition currents, and higher wire tip temperatures led to shorter arc ignition times (AITs) with the same chemical composition, diameter, and extension. Based on the characteristics of the welding wire end structures and the contact resistance between the CWW and workpiece, a suitable mathematical model of the AIT was developed. The model was validated using experimental arc ignition images. The AITs for the unsmooth smooth and preheated smooth wire ends were 14, 20, and 11 ms, respectively, essentially consistent with the model calculations. [ABSTRACT FROM PUBLISHER]

In the present investigation, multi-pass gas metal arc welding (GMAW) of SA516 Gr70 carbon steel was carried out by different filler wires such as solid, metal cored and flux cored, wherein, other process parameters were kept constant. The hybrid approach of multi-pass filler wires was applied to obtain three different welds. The root pass was filled by a solid wire for all three cases while the subsequent filler pass was applied through solid, flux-cored and metal cored filler wires, respectively. Metallographic, mechanical and metallurgical analyses such as macrograph study, optical microscopy, tensile testing and hardness variations were performed to address the quality of weld. The results revealed that defect-free sound welds were produced by the hybrid approach of different filler wires in multi-pass GMAW. Overall cost and time reduction can be achieved through hybrid filler welds, without affecting their mechanical strength. Angular distortion was reported minimum at hybrid weld of solid and metal cored filler wire. Maximum reinforcement with higher penetration was observed at weld of solid and metal cored filler wire. Impact toughness was reported higher in case of hybrid weld of solid and flux cored filler wire. Higher macro hardness was reported at weld of solid and flux cored filler wire. [ABSTRACT FROM PUBLISHER]

Wire-feed additive manufacturing is cost competitive and efficient in producing large and complex components in aerospace applications. However, for the additive manufacturing technologies with lateral wire feeding, including laser wire additive manufacturing, electron beam freeform fabrication, plasma arc welding, and gas tungsten arc welding, it is difficult to obtain uniform deposit due to the variable wire feeding direction. In this work, high-angle wire feeding method is proposed to obtain uniform deposit in gas tungsten arc welding-based additive manufacturing. The results illustrate that low wire feeding angle (30°–50°) causes the deposition to break at the back feeding, meanwhile too high wire feeding angle (70°) leads to many littered droplets on one side of the deposition at the condition of side feeding. A uniform deposition can be obtained at the optimal wire feeding angle of 60° in any wire feeding direction, and the reasons have been discussed based on the temperature distribution characteristics of the arc and molten pool. Furthermore, the deposition layers exhibit similar columnar priorβgrains, basketweave microstructure, and tensile properties from different wire feeding directions. [ABSTRACT FROM AUTHOR]

Štore Steel Ltd. makes more than 1400 steel grades. The highest costs in steel production from scrap stems from the electric arc furnace electric energy consumption. Electrical energy is used to produce heat energy generated by the burning arc between the graphite electrodes and steel scrap. In general, the balanced heat input of all electrodes is essential. Based on the input of thermal energy from all electrodes, also the possibility of occurrence of hot and cold spots in the electric arc furnace can be determined. Perception of and the elimination of the unequal heat load of electrodes have a major impact on reducing operating costs and increasing the efficiency of the electric arc furnace production. Most authors have modeled the arc furnace as an electrical equivalent circuit, where the electric arc is modeled using the macroscopic approach. In this paper, the microscopic approach to the electric arc model is described, where a set of equations (electrical neutrality, Dalton law, Saha–Eggert) was solved using differential evolution algorithm. The results of modeling were practically confirmed by measuring electric parameters (voltage, current, active power) during the electric arc furnace operation. In November 2016, the investment in a new electrode controller using implemented logic will be carried out. [ABSTRACT FROM AUTHOR]

Special features of laser welding of aluminium alloys with laser and arc heat sources are investigated. Advantages and shortcomings of these methods are noted. Experiments were carried out to combine laser and arc heat sources for welding aluminium alloys. Equipment for hybrid welding is described. The technological parameters influencing the external formation of the welded joints are determined. Specific conditions for welding 1424 aluminium alloys with a thickness of 4.0 mm are presented. High-quality welded joints were produced by hybrid laser-arc welding in 1424 alloy with a thickness of 4.0 mm. [ABSTRACT FROM AUTHOR]

Crystal cracking is one of the major defects when large copper structures are joined by gas tungsten arc welding (GTA welding). In order to research the mechanism of crystal cracking, the criterion for crystal cracking formation has been optimized based on Prokhorov's theory, which shows that the interior deformation rate (Δϵ) is the main factor that leads to crystal cracking. A finite element model of thick copper plates in GTA welding based on the rigid constraint experiments has been established, and the Δϵ variation of the welds is obtained. The physical model of the tendency of crystal cracking has been established, and then the mechanism of crystal cracking has been discussed systematically by comparing the variations between Δϵ obtained from numerical simulations and the weld ductility (Pmin) obtained from hot-tension experiments within the brittle temperature range (BTR). Results show that during GTA welding, the values of Δϵ andPminare varied, respectively, with the temperature descending, and the tendency of crystal cracking and expansion velocity can be controlled by the value of (Δϵ − Pmin). Then experiments with the preheated temperatures of 300°C and 500°C, verified the validity of the optimized criterion of cracking. [ABSTRACT FROM PUBLISHER]

A new narrow-gap welding process is proposed by applying triple-wire gas indirect arc (TW-GIA). There are double power supplies and triple wires in this system. Power supplies are only connected between electrode wires and base materials are not linked to power supplies. Since there are different wire arrangements with TW-GIA, this article studies these wire arrangements and their effects on sidewall fusion for narrow-gap welding. Results show that different wire arrangements lead to variant arc behaviors and metal transfer, and consequently they lead to different situation of sidewall fusion. The heat to melt sidewalls is mainly from the indirect arc column and metal transfer with narrow-gap TW-GIA. When side wires deviate from the main wire to opposite directions, heat from arc columns and metal transfer can concentrate toward groove sidewalls. When the whole weld torch is lowered, heat from the indirect arc column and metal transfer increases at the weld bead root. [ABSTRACT FROM PUBLISHER]

Context:Augmented renal clearance (ARC) refers to enhanced renal elimination of circulating solute, and has attracted wide attention in recent years. Objective:This study evaluates the effects of ARC on serum vancomycin concentration in patients administered vancomycin. Materials and methods:This was a retrospective study in patients receiving vancomycin treatment at a dose of 1000 mg in every 12 h and undergoing serum monitoring admitted over a 2-year period (May 2013 to May 2015), in order to estimate the influence of ARC on serum vancomycin concentration. In this study, statistical comparisons were made on the results from patients grouped according to creatinine clearance (CLcr). Results:One hundred forty-eight patients were enrolled in our study. The results showed that ARC patients were significantly younger, with a significantly lower Scrand higher GFR. The CLcrand steady-state trough concentrations of serum vancomycin exhibited a logarithmic correlation (Rs = −0.699,R2 = 0.488,p < 0.01) in the patients included in our study. The trough vancomycin concentrations of 62.9% patients in high CLcrgroup were under 10 μg/mL. Discussion and conclusion:Since ARC was significantly associated with subtherapeutic serum vancomycin concentration, it was necessary to devise adjusted dosage regimens for these patients based on their CLcr. [ABSTRACT FROM AUTHOR]

A method is proposed for calculating the temperature field in welding with trapezoidal oscillations of the welding arc, including the equation of the temperature field for the scheme of the moving surface heat source with normal distribution, the equation of trapezoidal oscillation in the form of the sum of Fourier series and the experimentally determined dependence of the effective radius of the heating spot of the arc r0 on the welding conditions. The dependence of the effective radius of the heating spot of the arc r0 on the welding conditions is determined by the similarity methods for welding of low-carbon and low-alloy steels in CO2 and a mixture of the gases Ar + 20% CO2. The comparison of the calculated temperatures and the results obtained in full-size experiments in welding of the pipes shows that the proposed calculation method results in sufficiently accurate determination of the temperature fields for practical applications. [ABSTRACT FROM AUTHOR]

Tungsten inert gas (TIG) welding is commonly used for quality joining of ferrous and non-ferrous materials. But lower depth of penetration is one major shortcoming of TIG and more numbers of passes are required for thick plate joining. Use of activated flux layer on workpiece remarkably enhances penetration. In the present work, arc and metal flow behavior are studied to revisit and validate the presence and role of governing forces responsible for higher penetration in flux activated TIG (ATIG) welding. Arc behavior, material flow patterns are studied during conventional and activated TIG welding for AISI 304 stainless steel using four different activated fluxes by carrying out welding (when arc is moving) as well as keeping the arc halted (stationary arc) for all cases. Results clearly demonstrate the presence of electromagnetic Lorentz force and surface tension induced reverse Marangoni flow (strongly centripetal). These forces also push the metal flow downward near the center region of the molten pool and in many occasions penetration reaches beyond plate thickness in ATIG welding. [ABSTRACT FROM PUBLISHER]

Several regularities of the accumulation of vacuum arc metal macroparticles (MP) on the sample on repetitively pulsed biasing (105 Hz, 7 µs, −0.5 kV to −3.5 kV) have been investigated. It has been shown that the substrate temperature plays a very important role in controlling the MP amounts on the sample. A possibility to change the metal particle number density on the substrate in the range from 105/cm2 to 107/cm2, depending on bias pulse parameters, sample temperature, and ion plasma saturation current density, has been demonstrated. The shape of MPs and their adhesion to the substrate surface depends strongly on the MP energy balance in a high-voltage space charge sheath. [ABSTRACT FROM AUTHOR]

The dark-red membrane was prepared on AM50 magnesium alloys by using chemical conversion and micro-arc oxidation (MAO). The effects of MAO electrolyte and chemical conversion solution were researched through L9(34) orthogonal test to obtain formulation for the aforementioned process. Surface morphology, composition, and corrosion resistance were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), and electrochemical test. A dark-red membrane can be obtained by the following steps: first, a chemical conversion was carried out on AM50 alloys by placing them in a solution of 50 g/L KMnO4 and 100 g/L NH4H2PO4 at 50°C for 11 min; second, the prepared alloys were placed into MAO electrolytes containing 10 g/L Na2SiO3 and 5 g/L NaOH in order to obtain the dark-red-colored MAO ceramic membranes. The membranes that are mainly composed of SiO2, MnO, MnP, MgSiO3, and Mg2SiO4 have porous structures. MnO and MnP were identified to be responsible for giving color to the membrane. [ABSTRACT FROM AUTHOR]

The South African maize sector has been revolutionised from a system of production with low use of modern technologies to a leading maize producer in the African continent. That transformation is in part attributable to South Africa's investment in the national maize cultivar trials, which have facilitated the adoption and use of maize cultivars that are highly adapted to commercial farmer localities, causing considerable gains in yields. The economic value of the public investment in the trials remains unknown. This study uses experimental yields spanning 1977 - 2012 to attribute the influence of the national maize cultivar trials to maize yield improvement on farmer localities in the Highveld region of South Africa. Using attribution methods, the study estimates that 24.3 kg per hectare of extra maize yields accrued to commercial maize producers because of the national maize trials. The economic value of these investments was found to be R1.4billion (in 2012 currency values). The study estimates that South Africa received R37 of benefit for every rand invested by the Agricultural Research Council (ARC) in the trials. [ABSTRACT FROM PUBLISHER]

Experiments are conducted to deposit SS304 L powders on SS316 plates by plasma transfer arc welding process with varying four input process parameters, namely scanning speed, powder feed rate, stand-off distance, and current. The effects of these four input process parameters on deposition geometry, dilution, and bead continuity are investigated in this study. Attempts have been made to explain the experimental results with only two compound parameters, “energy deposition per length” and “powder deposition per length” instead of four independent input process parameters. It is observed that the variation of dilution is very little when the scanning speed increases from 100 to 600 mm/min and other process parameters remain constant. When the powder feed rate increases and other parameters remain constant, initially the dilution decreases rapidly and attains a minimum value which do not change further with increase in powder feed rate. It is also observed that the dilution remains almost constant around 6–9% as the stand-off distance changes from 7 to 11 mm and other process parameters remain constant. The formation of nonuniform bead is found to be due to insufficient energy deposition per length per mass of supplied powder. [ABSTRACT FROM AUTHOR]

Magmatic Ni-Cu sulphide deposits are commonly associated with mafic rocks within the marginal areas of Archean or Proterozoic cratons. The Kleva Ni-Cu sulphide deposit in southeast Sweden is hosted by gabbro–diorite rocks and is sandwiched between two Palaeoproterozoic magmatic arcs: the Transscandinavian Igneous Belt (TIB) and the Oskarshamn–Jönköping Belt (OJB). Major and trace element data corroborate an arc origin for the Kleva intrusive complex. The variety of rocks and geochemical signatures suggest that it formed from several magmatic pulses. Despite the occurrence of supracrustal xenoliths, there is a lack of trace element evidence for significant assimilation. Mafic intrusions are abundant in southeast Sweden and are generally inferred to be synchronous with the TIB. Of these, Kleva is the only known Ni-Cu deposit, and it is unclear if it is associated with the OJB or TIB. Here, we present zircon and baddeleyite U-Pb dates of 1788 ± 4 Ma, 1788 ± 5 Ma and 1792 ± 3 Ma. We interpret a 1790 Ma date to be the best estimate of the crystallisation age of the Kleva intrusive complex, indicating that the emplacement of mafic magma is coeval with the voluminous arc-related TIB magmatism in the area. [ABSTRACT FROM PUBLISHER]

Many cutting operations are necessary for tubular structures and the wellhead during platform decommission. Electric arc cutting technology for casing and wellhead inner cutting is presented in this study. The electric arc cutting system eliminates the plasma gas system and focuses only on high cutting efficiency given that this cutting operation has no requirements on dimensional accuracy. An arc ignition circuit that is different from traditional arc cutting power is introduced. This study aims to explore cutting performance, such as cutting efficiency and electrode wear. Several cutting parameters, including the working medium, electrode material, electrode diameter, cutting current, and workpiece thickness, are investigated by a series of experiments to analyze cutting performance. Cutting time and electrode wear rate are obtained to evaluate the cutting performance. The morphological features of the experimental results are also investigated. Results show that electric arc cutting technology can be employed to cut a workpiece effectively in sea water with a 4mm tungsten electrode. Cutting performance is affected significantly by cutting current and velocity. A 13 3/8inch casing is cut within 5min in the laboratory with optimal machining parameters, which allow for a good cutting effect. [ABSTRACT FROM PUBLISHER]