Search

Separation of titanium and silicon oxides in the melt of quartz–leucoxene concentrate of the Yarega deposit under diffuse arc heating was investigated. Melting was carried out in argon at atmospheric pressure at direct current in a graphite crucible with an arc power of ≈25 kW. The crucible with the material was the anode of the arc. The arc heating was dispersed by applying an axial magnetic field. At the same time, a diffuse anode spot with a current density of 8 A/cm2 was formed on the surface of the material. The current–voltage parameters of the diffuse arc were investigated. As a result of melting, an oxide ingot consisting of two phases was obtained, one of which is enriched in titanium oxide, and the other in silicon oxide. However, the separation of these oxides did not occur completely because of the high cooling rate of the melt. Despite the low current density in the heating spot, the melt evaporated intensely. Evaporation occurred congruently. Owing to the high temperature of the bath mirror, no volatile titanium oxide evaporated along with the volatile silicon oxide. Condensation of the evaporated material occurred selectively. A condensate consisting almost entirely of SiO2 was formed in the form of powder on the cooled surfaces near the crucible. The specific surface area of the powder was 120 m2/g. The evaporated TiO2 was removed with the exhaust gas. [ABSTRACT FROM AUTHOR]

Working memory (WM) is a cognitive function important for guiding the on‐going or upcoming behavior. A memory‐related protein Arc (activity‐regulated cytoskeleton‐associated protein) is implicated in long‐term memory consolidation. Recent evidence further suggests the involvement of hippocampal Arc in spatial WM. The medial prefrontal cortex (mPFC) is a key brain region mediating WM. However, the role of mPFC Arc in WM is still uncertain. To investigate whether mPFC Arc protein is involved in WM performance, delayed non‐match to sample (DNMS) T‐maze task was performed in rats with or without blocking new synthesis of mPFC Arc. In DNMS task, a 10‐s or 30‐s delay between the sample run and the choice run was given to evaluate WM performance. To block new Arc protein synthesis during the DNMS task, Arc antisense oligodeoxynucleotides (ODNs) were injected to the bilateral mPFC. The results show that, in rats without surgery for cannula implantation and subsequent intracerebral injection of ODNs, WM was functioning well during the DNMS task with a delay of 10 s but not 30 s, which was accompanied with a significantly increased level of mPFC Arc protein, indicating a possible link between enhanced Arc protein expression and the performance of WM. After preventing the enhancement of mPFC Arc protein expression with Arc antisense ODNs, rat's WM performance was impaired. These findings support enhanced mPFC Arc protein expression playing a role during WM performance. [ABSTRACT FROM AUTHOR]

A current-limiting and consequent direct current (DC) arc interruption requires an increase in arc resistance r a r c for a DC fuse. Flattery silica (SiO2) sand has been used as an arc quenching medium in fuses for decades. However, there are few reports about a novel arc quenching medium which enables more r a r c increases compared to flattery SiO2 sand. This paper uniquely selected a novel arc quenching medium based on the following material properties: (1) electrical resistivity and thermal conductivity in the solid phase, (2) the possibility of r a r c increasing in the gas phase, (3) the possibility of electrical insulation after re-solidification, and (4) the cost of materials. As a result, we originally selected a powder mixture of silicon-nitride (Si3N4) and flattery SiO2 sand as a promising novel arc quenching medium. Therefore, DC interruption experiments were performed using a Si3N4/flattery SiO2 sand powder mixture under different Si3N4 concentration conditions. As a result of 1000 A DC arc quenching experiments, the utilization of Si3N4 powder with the flattery SiO2 sand successfully increased the arc resistance r a r c during the arc quenching process. The increasing Si3N4 concentration exhibited a further increase in r a r c during the arc quenching process. As a result of the r a r c increase, the arc quenching time was significantly shortened to 30 ms for 30 wt.% Si3N4 conditions from 54 ms for the SiO2 sand conditions. In addition, utilization of Si3N4 powder achieved high insulation resistance over few MΩ after DC arc interruption. The above results clearly indicate that utilization of Si3N4 powder with flattery SiO2 sand can increase the DC interruption performance of the fuse. [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]

During the dissection of 11 stiffs, we observed the presence of an accessory muscle in the axillary fossa, known as the dorsalis major muscle arch or axillary Carl Langer muscle. This is the main anatomical variation in the walls of the axillary region. This case was reported because of the low frequency of this variation in the axillary region, and the vital importance of incorporating the possible presence of these notions into axillary curage techniques, which may find themselves modified intraoperatively. Ignorance of the dorsalis major muscle arch may be the cause of intra- and postoperative complications during axillary curage or breast reconstruction using a dorsalis major flap. [ABSTRACT FROM AUTHOR]

Aiming at the electrical safety problem of a high-voltage lithium-ion battery system caused by an arc, and based on the establishment of a battery arc fault experimental platform, the evolution law of safety caused by an arc in the negative terminal of a battery system under different working conditions is discussed. On this basis, a battery arc evolution model based on magnetohydrodynamics is established to analyze the arc's electro-thermal coupling characteristics to further obtain the distribution of the arc's multi-physical field. The results show that the arc generated by the high-voltage grade battery pack will break down the cell's shell and form a hole, resulting in electrolyte leakage. When the loop current is 10 A, the evolution law of arc voltage and current is basically the same under different supply voltages, charges, and discharges. The accuracy of the battery arc simulation model is verified by comparing the simulation with the experimental results. The research in this paper provides a theoretical basis for the electrical safety design of lithium-ion batteries caused by the arc, fills the gaps in the field of battery system arc simulation, and is of great significance for improving the safety performance of arc protection. [ABSTRACT FROM AUTHOR]

Flame kernel generation is essential to the stability and efficiency of combustion in a spark engine. In this study, the initial process of flame kernel generation was studied in an optical spark engine. The engine was operated with the λ adjusted from 1.0 to 1.5, respectively. Meanwhile, the continuous arc motion was inventively quantified. First, the impact of single-coil and multi-coil discharge on the stability of the combustion and knocking tendency are examined. Secondly, the differences in arc development between single-coil and multi-coil discharge and the effect of the shortening phenomenon on the generation of the flame kernels are compared by optical images. Finally, arc shortening feathers (including timing, extent, and spatial location) are statistically analyzed over multiple cycles in conjunction with combustion phase. The results show that multi-coil discharge can make the flame kernels larger, which could keep the flame kernels from quenching. They also show that variations in arc shortening are linked to cycle-to-cycle fluctuations. Furthermore, a principal component analysis is done on the features of the first two arc shortenings and the CA05 phases. Precision control of the arc shortening features can greatly enhance the spark engine’s initial flame kernel stability and lower cycle-to-cycle fluctuations.

Background and aims: This research aimed to investigate the effect of 8 weeks of interval training and the use of cineole, linalool, and bourbonene on MAPK/Arc gene expression and learning in Alzheimer’s disease (AD) rats. Methods: In this experimental study, 40 AD rats were randomized into eight groups, including (1) control, (2) AD, (3) AD+aerobic training (AT), (4) AD+linalool, cineole, and bourbonene (LCB), (5) AD+AT+LCB, (6) AT+AD, (7) LCB+AD, and (8) AT+LCB+AD. AD was induced by injecting amyloid-beta (Aβ1)-42 into the hippocampus of rats. The interval training protocol was performed five days per week for eight weeks before and after AD induction. Linalool at a concentration of 25 mg/kg, cineole at a concentration of 10 µM, and β-bourbonene at a concentration of 10 µg/mL were used for eight weeks. One-way analysis of variance was used for between-group comparisons, and Tukey’s test was used for pairwise comparisons at P≤0.05. Results: AD induction caused a significant decrease in MAPK/Arc gene expression in hippocampal tissue (P=0.001). Interval exercise and consumption of three herbal drugs significantly increased gene expression of Arc (P=0.001) and MAPK (P=0.001). AD induction decreased learning (P=0.001). Interval exercise and consumption of three herbal medicines caused a significant increase in learning (P=0.001). Conclusion: Interval exercise and using three herbal medicines have more favorable effects on improving MAPK/Arc gene expression and learning in AD than each alone.

A carbon brush/collector ring set will have phenomena such as firing and ablation during operation, which is due to the existence of various abnormal contact modes of the brush/ring during operation, thus changing the carbon brush/collector ring interface state. To analyze the effects of different contact modes on the performance of the brush/ring, in this paper, we construct the contact modes of the air gap (loss of contact leads to the existence of a small gap between the two surfaces), direct contact (contact with abrasive particulate media), and surface porosity contact (contact when there is a large pit on the surface of the collector ring due to manufacturing quality defects and abnormal abrasion), and analyze the effects of the various states on the core parameters such as current conduction, ring surface damage, and carbon brush abrasion, which provide a basis for the active suppression of the damage.

Although great progress has been made in transgenic technology, increasing the expression level and thus promising the expected phenotypes of exogenous genes in transgenic plants is still a crucial task for genetic transformation and crop engineering. Here, we conducted a comparative study of the enhancing efficiency of three putative translational enhancers, including Ω (natural leader from a plant virus), OsADH 5′ (natural leader from a plant gene), and ARC (active ribosomal RNA complementary), using the transient gene expression systems of Nicotiana benthamiana and Chirita pumila. We demonstrate that three tandem repeats of ARC (3 × ARC) are more efficient than other enhancers in expression. The enhancing efficiency of 6 × ARC is further increased, up to 130 times the expression level without the insertion of enhancers. We further evaluated the enhancing efficiency of 6 × ARC under agrobacterium-mediated transformation systems. In C. pumila, 6 × ARC significantly amplifies the phenotypic effect of CpCYC1 and CpCYC2 in repressing stamen development and yellow pigmentation. In Arabidopsis thaliana, 6 × ARC and the AtAP1 promoter work together to promote the accumulation of anthocyanin pigments in vegetative and reproductive organs. Most significantly, the fusion of 6 × ARC in a CpCYC1/2 transgenic system in C. pumila fully reveals that these genes have the complete function of repressing the yellow spots, displaying an advantage in manifesting the function of exogenous genes. This study highlights the application potential of the enhancer 6 × ARC in gene function research in plants.

This study proposes a cost-effective multigeneration system that integrates a supercritical carbon dioxide (sCO2) power cycle with a liquefied natural gas (LNG) regasification process. The system aims to deliver electricity, cooling, heating, and hydrogen simultaneously. Utilizing the temperature difference between the sCO2 cycle and the LNG thermal sink, an ammonia-water-based absorption refrigeration cycle (ARC) recovers waste heat from the sCO2 power cycle, producing cooling. The elevated ammonia concentration at the ARC's condenser outlet is leveraged by a heat pump system for heating production. Concurrently, cold energy from LNG is used to recover latent heat from the condenser and heat rejected from the sCO2 power cycle, providing inputs for additional electrical power through an NG turbine. The system incorporates a PEM electrolyzer (PEME) for hydrogen production. A comprehensive examination, including energy, exergy, and exergoeconomic analyses, evaluates system performance. A sensitivity analysis illustrates the impacts of key parameters. In the baseline scenario, the system achieves energy and exergy efficiencies of 62.79% and 54.89%, with a low product unit cost of 11.35 ($/GJ). The system demonstrates substantial net power output (259.184 MW), cooling capacity (88.938 MW), heating capacity (2.839 MW), and hydrogen production (391.68 kg/h). This robust performance, coupled with cost-effectiveness, positions the proposed system as a versatile and impactful solution for sustainable and environmentally friendly energy applications.

Summary: Epilepsy is a brain disorder affecting up to 1 in 26 individuals. Despite its clinical importance, the molecular mechanisms of epileptogenesis are still far from clarified. Our previous study showed that disruption of Clock in excitatory neurons alters cortical circuits and leads to generation of focal epilepsy. In this study, a GAD-Cre;Clockflox/flox mouse line with conditional Clock gene knockout in inhibitory neurons was established. We observed that seizure latency was prolonged, the severity and mortality of pilocarpine-induced seizure were significantly reduced, and memory was improved in GAD-Cre;Clockflox/flox mice. We hypothesize that mice with CLOCK knockout in inhibitory neurons have increased threshold for seizure, opposite from mice with CLOCK knockout in excitatory neurons. Further investigation showed Clock knockout in inhibitory neurons upregulated the basal protein level of ARC, a synaptic plasticity-associated immediate-early gene product, likely through the BDNF-ERK pathway. Altered basal levels of ARC may play an important role in epileptogenesis after Clock deletion in inhibitory neurons. Although sEPSCs and intrinsic properties of layer 5 pyramidal neurons in the somatosensory cortex exhibit no changes, the spine density increased in apical dendrite of pyramidal neurons in CLOCK knockout group. Our results suggest an underlying mechanism by which the circadian protein CLOCK in inhibitory neurons participates in neuronal activity and regulates the predisposition to epilepsy.

Copyright of Electric Drive for Locomotives is the property of Electric Drive for Locomotives Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Macrocrysts (large crystals) in magmas offer a premier record of pre‐eruptive magma storage conditions encoded in their chemistry and texture. Careful study of macrocryst zoning can deconvolve the conditions of crystal growth and the relative time a magma spends in a given physical‐chemical state prior to eruption. Importantly, identifying discrete macrocryst zones requires consideration of both chemistry and texture simultaneously. Here, we employ a novel image segmentation approach to characterize zoning from 2D chemical maps of plagioclase macrocrysts. We apply the method to 15 volcanic eruptions, across three stratigraphic sections, to track statistical differences in crystal zoning through relative time at an arc volcano (Mount Liamuiga, Saint Kitts). Plagioclase from the 15 eruptions are described by 7 unique textural‐chemical zoning populations, which we term "zoning groups," each of which has a unique An# fingerprint. Two of the studied stratigraphic sections overwhelmingly record low‐An# zoning groups (ZGs), whereas the other section records mostly high‐An# ZGs, suggestive of two distinct storage conditions. Using observations from equilibrium experiments relevant to Saint Kitts bulk magma compositions, we show that differences in melt H2O are the primary drivers of the An# variability. Negative whole rock K2O versus predicted H2O trends are suggestive of ubiquitous H2O‐saturated conditions throughout the middle and upper crust, with a correlation between H2O‐saturated storage pressure (Psat) and eruptive dynamics; magmas stored in the upper‐crust (0.48 ± 0.28–1.08 ± 0.45 kbar) produce larger‐volume, pumice‐rich eruptions compared to magmas stored in the middle crust (3.29 ± 0.87–3.88 ± 1.05 kbar) which generally produce smaller‐volume, centimeter to decimeter‐thick fall deposits. Plain Language Summary: The physical and chemical conditions under which a magma, a mixture of liquid melt and solid crystals, is stored in the Earth's crust determines how it erupts on Earth's surface. A reliable record of these pre‐eruptive conditions is the complex zoning inside crystals, which consist of textural‐chemical patterns that are interpretable by petrologists. Here, we study a series of volcanic eruptions from Mount Liamuiga (Saint Kitts, Lesser Antilles) and focus on the mineral plagioclase which is present in all samples. A novel image segmentation approach was used to rapidly break down 624 crystals from 15 volcanic samples into coherent zones. By combining plagioclase zoning data with published experimental observations, we identified two distinct pre‐eruptive magma storage regions, namely a deeper (∼3.5 kbar) and a shallower (∼1 kbar) region. Over the entire pressure range, magmas are shown to coexist with a volatile phase, which has implications for the physical properties of the Earth's crust in which these magmas are stored. Shallower stored magmas produce larger‐volume, pumice‐rich eruptions compared to magmas stored deeper, which generally produce smaller‐volume centimeter‐thick to decimeter‐thick fall deposits. The information we gather is important for interpreting the monitoring signals of future volcanic unrest on Saint Kitts. Key Points: Our image segmentation method identifies zoning features in 624 plagioclase crystals that are correlated across 15 volcanic eruptionsNegatively correlated whole rock K2O and pre‐eruptive H2O demonstrates that H2O‐saturated conditions were ubiquitous prior to eruptionLarger‐volume deposits record shallower storage (0.6–0.7 kbar) than the commonest centimetric fall deposits (3.3–3.9 kbar) [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]

Arc beads generated from metal conductors by arc discharges have a risk of causing fires when contacting the combustibles. In this work, the process of arc bead generation from conductors due to arc discharge was investigated experimentally. The copper conductors with four different diameters (1.5, 2.5, 4, 6 mm2) were chosen to produce arc beads by the arc discharges with currents from 60 to 220 A. It was observed that the arc bead was generated when its gravity overcame the surface tension between the arc bead and the conductor. The diameter of the arc bead was found to increase with the conductor diameter, and an expression was established to describe this relationship. It was also found that the minimum discharge time required for the arc bead formation was negatively correlated with the discharge current, but positively correlated with the conductor diameter. The findings of this work help assess the ignition risk caused by arc beads [ABSTRACT FROM AUTHOR]

This paper defines a new operation through extending the idea of the 0-dimensional crossing change and Shimizu's 2-dimensional region crossing change [A. Shimizu, Region crossing change is an unknotting operation, J. Math. Soc. Jpn. 66(3) (2014) 693–708, doi:10.2969/jmsj/06630693] to a 1-dimensional version called the arc crossing change. We will also prove that the arc crossing change is an unknotting operation with the help of Gauss diagrams. [ABSTRACT FROM AUTHOR]

Igneous rocks of the Jurassic continental arc of southwest North American Cordillera crop out in the region between Cananea and Nacozari, in northeastern Sonora, Mexico. Contemporaneous igneous rocks occur farther south in the Nazas rift province; however, their tectonic affinity is debated between the southern extension of the Cordilleran arc and an origin associated with decompressive mantle melting during the Pangea breakup. We consider that the studied rocks represent the southernmost expression of the Jurassic continental arc. Four magmatic units are distinguished based on geology, U–Pb zircon geochronology, and geochemical composition. They comprise the Buenos Aires granite dated at 183.8 ± 1.1 Ma, the Mababi granite with ages of 175.5 ± 1.8, 173.5 ± 1.8, and 171.7 ± 1.0 Ma, the Elenita Formation volcanic rocks dated at 169.7 ± 1.7 Ma, and the Cerro Blanco granite dated at 162.3 ± 2.4 Ma. The studied samples correspond to highly differentiated rocks with high-silica contents (69–76 wt.%), low Mg# values (mostly <45), and alkali–calcic and peraluminous compositions suggesting crustal contamination. LREE-enriched normalized slopes with negative Eu anomalies and multielement plots characterized by well-developed negative anomalies of Nb–Ta, P, and Ti provide an unequivocal signal of the continental arc nature. In contrast to the Nazas province, where the Jurassic magmatism consists of discreet volcaniclastic sequences deposited in extensional basins with no evidence of plutonic rocks, the Jurassic continental arc of Arizona and northern Sonora forms a regionally coherent geological feature characterized by large exposures of volcanic and plutonic rocks. [ABSTRACT FROM AUTHOR]

Copyright of BSGF: Earth Sciences Bulletin is the property of EDP Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Background and aims: This research aimed to investigate the effect of 8 weeks of interval training and the use of cineole, linalool, and bourbonene on MAPK/Arc gene expression and learning in Alzheimer’s disease (AD) rats. Methods: In this experimental study, 40 AD rats were randomized into eight groups, including (1) control, (2) AD, (3) AD+aerobic training (AT), (4) AD+linalool, cineole, and bourbonene (LCB), (5) AD+AT+LCB, (6) AT+AD, (7) LCB+AD, and (8) AT+LCB+AD. AD was induced by injecting amyloid-beta (Aβ1)-42 into the hippocampus of rats. The interval training protocol was performed five days per week for eight weeks before and after AD induction. Linalool at a concentration of 25 mg/kg, cineole at a concentration of 10 µM, and β-bourbonene at a concentration of 10 µg/mL were used for eight weeks. One-way analysis of variance was used for between-group comparisons, and Tukey’s test was used for pairwise comparisons at P≤0.05. Results: AD induction caused a significant decrease in MAPK/Arc gene expression in hippocampal tissue (P=0.001). Interval exercise and consumption of three herbal drugs significantly increased gene expression of Arc (P=0.001) and MAPK (P=0.001). AD induction decreased learning (P=0.001). Interval exercise and consumption of three herbal medicines caused a significant increase in learning (P=0.001). Conclusion: Interval exercise and using three herbal medicines have more favorable effects on improving MAPK/Arc gene expression and learning in AD than each alone. [ABSTRACT FROM AUTHOR]

For a disk $ D $ in the plane $ \mathbb R^2 $ and a plane map $ f $, we give several conditions on the restriction of $ f $ to the boundary $ \partial D $ of $ D $ which imply the existence of a fixed point of $ f $ in some specified domain in $ D $. These conditions are similar to those appeared in the intermediate value theorem for maps on the real line. As an application of this result, we establish a fixed point theorem for plane maps having an outflanking arc, which extends the famous theorem due to Brouwer: if $ f $ is an orientation-preserving homeomorphism on the plane and has a periodic point, then it has a fixed point. [ABSTRACT FROM AUTHOR]

Injury responses require communication between different cell types in the skin. Sensory neurons contribute to inflammation and can secrete signaling molecules that affect non-neuronal cells. Despite the pervasive role of translational regulation in nociception, the contribution of activity-dependent protein synthesis to inflammation is not well understood. To address this problem, we examined the landscape of nascent translation in murine dorsal root ganglion (DRG) neurons treated with inflammatory mediators using ribosome profiling. We identified the activity-dependent gene, Arc, as a target of translation in vitro and in vivo Inflammatory cues promote local translation of Arc in the skin. Arc-deficient male mice display exaggerated paw temperatures and vasodilation in response to an inflammatory challenge. Since Arc has recently been shown to be released from neurons in extracellular vesicles (EVs), we hypothesized that intercellular Arc signaling regulates the inflammatory response in skin. We found that the excessive thermal responses and vasodilation observed in Arc defective mice are rescued by injection of Arc-containing EVs into the skin. Our findings suggest that activity-dependent production of Arc in afferent fibers regulates neurogenic inflammation potentially through intercellular signaling.SIGNIFICANCE STATEMENT Nociceptors play prominent roles in pain and inflammation. We examined rapid changes in the landscape of nascent translation in cultured dorsal root ganglia (DRGs) treated with a combination of inflammatory mediators using ribosome profiling. We identified several hundred transcripts subject to rapid preferential translation. Among them is the immediate early gene (IEG) Arc. We provide evidence that Arc is translated in afferent fibers in the skin. Arc-deficient mice display several signs of exaggerated inflammation which is normalized on injection of Arc containing extracellular vesicles (EVs). Our work suggests that noxious cues can trigger Arc production by nociceptors which in turn constrains neurogenic inflammation in the skin.

Introduction: Alzheimer's disease is a common progressive neurogenerative disease that leads to dementia and destruction of brain cells, especially in areas related to learning and memory such as the hippocampus. The role of the Arc gene in synaptic flexibility and memory consolidation has been proven and its expression is strongly influenced by neuronal activity. The aim of this study was to investigate the effect of Lactobacillus fermentum on the expression of Arc (effective in synaptic flexibility and memory consolidation) and CREB (effective in stabilizing synaptic changes during learning) genes, involved in the memory of Alzheimer's rats. Material & ethods: In this study that was conducted in 2019, 30 male Wistar rats were divided into 5 groups (control, Alzheimer and 3 groups as treatment). In the treatment groups, simultaneously with induction of Alzheimer by stereotaxic method with streptozotocin, supernatant of Lactobacillus fermentum PTCC 1744 in MRS broth with doses of 108, 107, and 106 cfu/ml was injected intraperitoneally for 21 days. After RNA extraction from hippocampus samples, cDNA was synthesized and the expression of the genes was evaluated by real-time PCR and LinReg PCR software. Findings: The data showed an increase in gene expression of Arc and CREB in the treatment groups with a dose of 106 cfu/ml compared to the Alzheimer's group and the difference was significant (P

As a promising structural material, carbon fiber reinforced thermoplastic (CFRTP) has been gradually applied on aircrafts. The lightning arc adhesion characteristics of CFRTP, however, are still unclear. Therefore, the arc adhesion characteristics of CFRTP were studied by simulating the lightning test method. Based on the finite element method, the effect of CFRTP on spatial electric field was analyzed and compared with that of metal materials. It is found that for the structure containing both CFRTP and metal materials, CFRTP is possible to be attached by the lightning discharging channel, but the probability is lower than that of the metal material by 22.5%. In the process of lightning arc adhesion, single upward leader and multiple upward leaders appear on the surface of CFRTP, resulting in the corresponding single or multiple arc attachment points. Simultaneous adhesion of lightning arc on both CFRTP and metal material also occurs. The spatial electric distribution obtained by simulation is consistent with the experimental results. This paper can provide the basis for the lightning characteristics and damage response of CFRTP.

Social isolation during adolescence can increase the risk of mental disorders. Epigenetic changes induced by chronic social isolation may serve as a mechanism underlying emotional disturbances. To test this, we exposed female mice to a post-weaning 6-week social isolation (SI) stress. We found the significantly increased methylation of histone H3 at lysine 9 (H3K9), a histone mark linked to gene repression, as well as the increased H3K9 methyltransferases SUV39H1 and SETDB1, in prefrontal cortex (PFC) of SI females. To find out potential downstream genes affected by this epigenetic alteration, we examined genes linked to neuronal and synaptic functions. Activity-dependent genes, including Arc, c-Fos and Npas4, were significantly reduced in PFC of SI females, correlated with the increased H3K9me2 occupancy around Arc enhancer. Treatment of SI females with UNC0642, a selective inhibitor of H3K9 methylation, significantly attenuated the anxiety-like behavior and elevated Arc expression. These results have revealed an epigenetic mechanism and intervention avenue for anxiety induced by chronic social isolation.

Abstract Macrocrysts (large crystals) in magmas offer a premier record of pre‐eruptive magma storage conditions encoded in their chemistry and texture. Careful study of macrocryst zoning can deconvolve the conditions of crystal growth and the relative time a magma spends in a given physical‐chemical state prior to eruption. Importantly, identifying discrete macrocryst zones requires consideration of both chemistry and texture simultaneously. Here, we employ a novel image segmentation approach to characterize zoning from 2D chemical maps of plagioclase macrocrysts. We apply the method to 15 volcanic eruptions, across three stratigraphic sections, to track statistical differences in crystal zoning through relative time at an arc volcano (Mount Liamuiga, Saint Kitts). Plagioclase from the 15 eruptions are described by 7 unique textural‐chemical zoning populations, which we term “zoning groups,” each of which has a unique An# fingerprint. Two of the studied stratigraphic sections overwhelmingly record low‐An# zoning groups (ZGs), whereas the other section records mostly high‐An# ZGs, suggestive of two distinct storage conditions. Using observations from equilibrium experiments relevant to Saint Kitts bulk magma compositions, we show that differences in melt H2O are the primary drivers of the An# variability. Negative whole rock K2O versus predicted H2O trends are suggestive of ubiquitous H2O‐saturated conditions throughout the middle and upper crust, with a correlation between H2O‐saturated storage pressure (Psat) and eruptive dynamics; magmas stored in the upper‐crust (0.48 ± 0.28–1.08 ± 0.45 kbar) produce larger‐volume, pumice‐rich eruptions compared to magmas stored in the middle crust (3.29 ± 0.87–3.88 ± 1.05 kbar) which generally produce smaller‐volume, centimeter to decimeter‐thick fall deposits.

The present study introduces a novel tri-generation system that is highly efficient and cost-effective, employing a supercritical CO2 (sCO2) Brayton cycle as the primary mover and harnessing the cooling potential from liquefied natural gas (LNG) as a heat sink. This innovative system simultaneously provides electricity, cooling, and hydrogen. By capitalizing on the substantial temperature difference between the high-temperature sCO2 power cycle and the low-temperature LNG cold source, an integrated combination of the Kalina cycle (KC) and organic Rankine cycle (ORC) is utilized. Additionally, the system incorporates a proton exchange membrane electrolyzer (PEME) and an absorption refrigeration cycle (ARC) to create a highly efficient trigeneration system. The system is rigorously evaluated through energy, exergy, and exergoeconomic analyses, which are critical for assessing performance. Additionally, this study conducts a parametric investigation to elucidate the impact of key parameters on system performance. Furthermore, optimization is performed using a genetic algorithm (GA), with the objective of maximizing energy and exergy efficiencies or minimizing the overall product cost. Results from the baseline scenario demonstrate impressive energy and exergy efficiencies of 54.38 % and 59.46 % respectively, along with a low total product unit cost of 11.642 ($/GJ), outperforming existing benchmarks in the literature. The system also provides substantial net power output, cooling capacity, and hydrogen production rates of 276.71 MW, 60.19 MW, and 176.25 kg/h, respectively. This combination of high performance and cost-effectiveness makes the proposed system a versatile choice, underscoring its significance in sustainable and environmentally friendly energy solutions.

This paper presents an innovative trigeneration system designed for efficient power, cooling, and hydrogen production. It combines a supercritical carbon dioxide (sCO2) power cycle with a Kalina cycle (KC) and an ammonia-water-based absorption refrigeration cycle (ARC), all integrated with a PEM electrolyzer (PEME) unit. The system optimally utilizes waste heat from the sCO2 power cycle to enhance power generation through the KC and provide cooling via the ARC. Additionally, it leverages the PEME system and KC-generated power for eco-friendly hydrogen production. Mathematical models, thermodynamic, and exergoeconomic analyses were performed, including parametric studies, optimization, and comparative analyses. The results indicate that the reactor experiences the highest exergy destruction rate, while components in the bottoming cycles exhibit lower exergy destruction. From an exergoeconomic perspective, the reactor and sCO2 turbine are ranked as the first and second most significant components. Under the optimal conditions, the system achieved a 9.76 % increase in exergy efficiency and a 6.63 % reduction in total product unit cost. The system also provides substantial net power output, cooling capacity, and hydrogen production rates of 261.74 MW, 123.95 MW, and 176.328 kg/h, respectively. These findings highlight the system's significant thermodynamic and economic advantages, making it a promising choice for diverse user needs.

Introduction: Age-related cognitive decline has been linked to distinct patterns of cellular dysfunction in the prelimbic cortex (PL) and the CA3 subregion of the hippocampus. Because higher cognitive functions require both structures, selectively targeting a neurobiological change in one region, at the expense of the other, is not likely to restore normal behavior in older animals. One change with age that both the PL and CA3 share, however, is a reduced ability to utilize glucose, which can produce aberrant neural activity patterns. Methods: The current study used a ketogenic diet (KD) intervention, which reduces the brain’s reliance on glucose, and has been shown to improve cognition, as a metabolic treatment for restoring neural ensemble dynamics in aged rats. Expression of the immediate-early genes Arc and Homer1a were used to quantify the neural ensembles that were active in the home cage prior to behavior, during a working memory/biconditional association task, and a continuous spatial alternation task. Results: Aged rats on the control diet had increased activity in CA3 and less ensemble overlap in PL between different task conditions than did the young animals. In the PL, the KD was associated with increased activation of neurons in the superficial cortical layers, establishing a clear link between dietary macronutrient content and frontal cortical activity. The KD did not lead to any significant changes in CA3 activity. Discussion: These observations suggest that the availability of ketone bodies may permit the engagement of compensatory mechanisms in the frontal cortices that produce better cognitive outcomes. [ABSTRACT FROM AUTHOR]

Flash sintering (FS) is an ultrafast sintering method with low energy consumption and facile operation even at room temperature. Research has shown that the FS of 3 mol.% yttria-stabilised zirconia (3YSZ) at room temperature is induced by the appearance of an electric arc at both ends of the sample. In this study, we experimentally observed the arc-induced FS of 3YSZ, simulated the arc generation process based on magnetohydrodynamic equations, and analysed the arc-induced FS mechanism from the perspectives of heat conduction and current distribution. The simulation results showed the surface-flashover-induced microsecond-level generation of the arc. The results also demonstrated that the electrical conductivity of the sample varied with the temperature distribution due to the thermal conductivity of the sample, which resulted in the occurrence of arcs and arc-induced FS. Therefore, increasing the thermal and electrical conductivities of a sample can improve the experimental success rate of FS at room temperature. • Arc-induced flash sintering of 3YSZ at room temperature analysed. • Arc generation simulated using magnetohydrodynamic equations. • Arc formation within microseconds due to surface flashover. • Competitive relation between the current densities of arc and sample. [ABSTRACT FROM AUTHOR]

The limited tritium resources available for the first fusion power plants (FPPs) make fuel self-sufficiency and tritium inventory minimization leading issues in FPP design. This work builds on the model proposed by Abdou et al (2020 Nucl. Fusion 61 013001), which analyzed the fuel cycle (FC) of a DEMOnstration nuclear FPP-class FPP with a time-dependent system-level model. Here, we use a modified version of their model to analyze the FC of an Affordable, Robust, Compact (ARC)-class tokamak and two versions of a Spherical Tokamak for Energy Production (STEP)-class tokamak. The ARC-class tokamak breeds tritium in a 2LiF + BeF2 liquid immersion blanket, while the STEP-class tokamak breeds tritium utilizing either a liquid-lithium blanket design or an encapsulated breeding blanket. A time-dependent system-level model is developed in Matlab Simulink® to simulate the evolution of tritium flows and tritium inventories in the FC. The main goals of this work are to assess tritium self-sufficiency of the ARC- and STEP-class designs and to determine quantitative design requirements that can be used to analyze the adequacy of a proposed FC system. These design requirements are aimed at achieving a low tritium inventory doubling time ( t d ) and a low start-up inventory ( I s t a r t u p ) while keeping the required tritium breeding ratio (TBR r ) as low as possible. We also consider how improvements in FC technology and POs affect TBR r and I s t a r t u p . The model results show that TBR r for ARC- and STEP-class FPPs should be achievable if the tritium burn efficiency (TBE) reaches 0.5%–1% (TBR r < 1.2). This assumes significant, but attainable, improvements over current abilities. However, the model results indicate that an FPP must achieve ambitious performance targets, including FPP availability > 70%, tritium processing time < 4 h, and the implementation of direct internal recycling (DIR). If future research yields major improvements to achievable TBE, it may be possible to achieve tritium self-sufficiency while operating at lower availability and without implementing DIR. [ABSTRACT FROM AUTHOR]

We derive an equation that enables to get the floating distance of floating images of an arc 3D display by the radius of the arc, the angle of the arc 3D substrate, the light source illumination angle, and the observer's angle. Conventional theoretical expression for the positions of the light source and observer relative to the center of the arc have been used to calculate the floating distance. However, when the arc3D substrate is inclined, it becomes more difficult to determine the floating distance from the actual positions of the light source and observer. In this paper, we derive an equation to approximate the floating distance from the positions of the light source and the observer while considering the tilt of the arc3D substrate and check the accuracy of the derived equation through experiments. [ABSTRACT FROM AUTHOR]

The activity-regulated cytoskeleton-associated protein (Arc/Arg3.1) is a neuronspecific immediate early gene (IEG) product. The protein regulates synaptic strength through modulation of spine density and morphology, AMPA receptor endocytosis, and as being part of a retrovirus-like inter-cellular communication mechanism. However, little is known about the detailed subsynaptic localization of the protein, and especially its possible presynaptic localization. In the present study, we provide novel electron microscopical data of Arc localization at hippocampal Schaffer collateral synapses in the CA1 region. The protein was found in both pre-and postsynaptic cytoplasm in a majority of synapses, associated with small vesicles. We also observed multivesicular body-like structures positive for Arc. Furthermore, the protein was located over the presynaptic active zone and the postsynaptic density. The relative concentration of Arc was 25% higher in the postsynaptic spine than in the presynaptic terminal. Notably, small extracellular vesicles labeled for Arc were detected in the synaptic cleft or close to the synapse, supporting a possible transsynaptic transmission of the protein in the brain. [ABSTRACT FROM AUTHOR]

Expression of the immediate early gene Arc/Arg3.1 (Arc), a key mediator of synaptic plasticity, is enhanced by neural activity and then reduced by proteasome‐dependent degradation. We have previously shown that the disruption of Arc degradation, in an Arc knock‐in mouse (ArcKR), where the predominant Arc ubiquitination sites were mutated, reduced the threshold to induce, and also enhanced, the strength of Group I metabotropic glutamate receptor‐mediated long‐term depression (DHPG‐LTD). Here, we have investigated if ArcKR expression changes long‐term potentiation (LTP) in CA1 area of the hippocampus. As previously reported, there was no change in basal synaptic transmission at Schaffer collateral/commissural‐CA1 (SC‐CA1) synapses in ArcKR versus wild‐type (WT) mice. There was, however, a significant increase in the amplitude of synaptically induced (with low frequency paired‐pulse stimulation) LTD in ArcKR mice. Theta burst stimulation (TBS)‐evoked LTP at SC‐CA1 synapses was significantly reduced in ArcKR versus WT mice (after 2 h). Group 1 mGluR priming of LTP was abolished in ArcKR mice, which could also potentially contribute to a depression of LTP. Although high frequency stimulation (HFS)‐induced LTP was not significantly different in ArcKR compared with WT mice (after 1 h), there was a phenotype in environmentally enriched mice, with the ratio of LTP to short‐term potentiation (STP) significantly reduced in ArcKR mice. These findings support the hypothesis that Arc ubiquitination supports the induction and expression of LTP, likely via limiting Arc‐dependent removal of AMPA receptors at synapses. [ABSTRACT FROM AUTHOR]

• T817MA attenuates OxyHb-induced oxidative stress and neurotoxicity. • T817MA regulates mitochondrial dynamics after OxyHb treatment. • T817MA protects against OxyHb via Sirt1 and Arc in vitro. • T817MA alleviates brain damage following SAH in vivo. • T817MA regulates mitochondrial dynamics, Sirt1 and Arc in vivo. Spontaneous subarachnoid hemorrhage (SAH) is an acute neurologic emergency with poor outcomes, and mitochondrial dysfunction is known as one of the key pathological mechanisms underlying the SAH-induced early brain injury (EBI). 1-{3-[2-(1-benzothiophen-5-yl)ethoxy]propyl} azetidin-3-ol maleate (T817MA) is a newly synthesized neurotrophic compound that has been demonstrated to exert protective effects against brain injury. Here, we investigated the effect of T817MA in neuronal injury following experimental SAH both in vitro and in vivo. Primary cultured cortical neurons were treated with oxyhemoglobin (OxyHb) to mimic SAH in vitro , and T817MA at concentrations higher than 0.1 μM reduced OxyHb-induced neuronal injury. T817MA treatment significantly inhibited lipid peroxidation, reduced neuronal apoptosis and attenuated mitochondrial fragmentation. The results of western blot showed that T817MA markedly reduced the expression of mitochondrial fission proteins, fission protein 1 (Fis-1) and dynamin-related GTPase-1 (Drp-1), but prolonged the expression of the postsynaptic protein activity-regulated cytoskeleton-associated protein (Arc). In addition, T817MA significantly increased the expression of sirtuin 1 (Sirt1), which was accompanied by preserved enzymatic of isocitrate dehydrogenase (IDH2) and superoxide dismutase (SOD). Knockdown of Sirt1 and Arc via small interfere RNA (siRNA) transfection partially prevented the T817MA-induced protection in cortical neurons. Furthermore, treatment with T817MA in vivo significantly reduced brain damage and preserved neurological function in rats. The decreased expression of Fis-1 and Drp-1, as well as the increased expression of Arc and Sirt1 were also observed in vivo. Taken together, these data indicate that the neuroprotective agent T817MA protects against SAH-induced brain injury via Sirt1- and Arc-mediated regulation of mitochondrial dynamics. [ABSTRACT FROM AUTHOR]

Localization of messenger RNA (mRNA) in dendrites is crucial for regulating gene expression during long‐term memory formation. mRNA binds to RNA‐binding proteins (RBPs) to form messenger ribonucleoprotein (mRNP) complexes that are transported by motor proteins along microtubules to their target synapses. However, the dynamics by which mRNPs find their target locations in the dendrite have not been well understood. Here, we investigated the motion of endogenous β‐actin and Arc mRNPs in dissociated mouse hippocampal neurons using the MS2 and PP7 stem‐loop systems, respectively. By evaluating the statistical properties of mRNP movement, we found that the aging Lévy walk model effectively describes both β‐actin and Arc mRNP transport in proximal dendrites. A critical difference between β‐actin and Arc mRNPs was the aging time, the time lag between transport initiation and measurement initiation. The longer mean aging time of β‐actin mRNP (~100 s) compared with that of Arc mRNP (~30 s) reflects the longer half‐life of constitutively expressed β‐actin mRNP. Furthermore, our model also permitted us to estimate the ratio of newly generated and pre‐existing β‐actin mRNPs in the dendrites. This study offers a robust theoretical framework for mRNP transport, which provides insight into how mRNPs locate their targets in neurons. [ABSTRACT FROM AUTHOR]

Memory deficits are central to many neuropsychiatric diseases. During acquisition of new information, memories can become vulnerable to interference, yet mechanisms that underlie interference are unknown. We describe a novel transduction pathway that links the NMDA receptor (NMDAR) to AKT signaling via the immediate early gene Arc and evaluate its role in memory. The signaling pathway is validated using biochemical tools and transgenic mice, and function is evaluated in assays of synaptic plasticity and behavior. The translational relevance is evaluated in human postmortem brain. Arc is dynamically phosphorylated by CaMKII (calcium/calmodulin-dependent protein kinase II) and binds the NMDAR subunits NR2A/NR2B and a previously unstudied PI3K (phosphoinositide 3-kinase) adapter p55PIK (PIK3R3) in vivo in response to novelty or tetanic stimulation in acute slices. NMDAR-Arc-p55PIK recruits p110α PI3K and mTORC2 (mechanistic target of rapamycin complex 2) to activate AKT. NMDAR-Arc-p55PIK-PI3K-mTORC2-AKT assembly occurs within minutes of exploratory behavior and localizes to sparse synapses throughout hippocampal and cortical regions. Studies using conditional (Nestin-Cre) p55PIK deletion mice indicate that NMDAR-Arc-p55PIK-PI3K-mTORC2-AKT functions to inhibit GSK3 and mediates input-specific metaplasticity that protects potentiated synapses from subsequent depotentiation. p55PIK conditional knockout mice perform normally in multiple behaviors including working memory and long-term memory tasks but exhibit deficits indicative of increased vulnerability to interference in both short-term and long-term paradigms. The NMDAR-AKT transduction complex is reduced in postmortem brain of individuals with early Alzheimer's disease. A novel function of Arc mediates synapse-specific NMDAR-AKT signaling and metaplasticity that contributes to memory updating and is disrupted in human cognitive disease. [ABSTRACT FROM AUTHOR]

Cataract, defined as the opacification of the lens that prevents clear vision, is a leading cause of vision loss and impairment worldwide. Elderly people comprise the highest proportion of those suffering from this eye disease. According to the National Institute of Health (NIH), the risk of developing aged-related cataract (ARC) increases with every decade of life, starting from the age of 40. Despite progress in surgical treatment methods, life-style modifications may be beneficial in prevention or slowing down the progression of ARC. This systematic review aims to summarize studies on the significance of specific nutritional patterns, dietary products, vitamins, minerals, and carotenoids intake in the onset or progression of ARC. In this context, the presented paper thoroughly analyzes 24 articles, following the PRISMA guidelines. The results indicate significant protective effects of various dietary patterns, including the Korean balanced diet, vegetarian diet, "dairy products and vegetables", "traditional", "antioxidant", and "omega-3" patterns. Additionally, the consumption of fruits, vegetables, legumes, nuts, skimmed yoghurt, fish, coffee, and vitamins has shown positive effects on cataract incidence. Therefore, further research seems to be essential to gain a better understanding of these associations and to create uniform dietary recommendations for both the vulnerable population and ARC patients. [ABSTRACT FROM AUTHOR]

In this study, we have developed a numerical model of the pulsed tungsten inert gas (TIG) arc, with a primary focus on the influence of the ambient atmosphere in wire arc additive manufacturing (WAAM), which is more approached to practical instances. The arc plasma behaviour and air transport during the pulsed TIG-based WAAM are investigated, and the effects of the nozzle diameter on the air transport are examined. It is indicated that the air is transported significantly into the zone near the sidewall of the AM buildup. Both the air concentration and the arc temperature vary periodically with the pulsed current, whereas the change in the air distributions noticeably falls behind that in the arc temperature fields. The variation in the air concentration is mainly caused by the backward flow of the arc plasma near the sidewall of the build, which varies periodically with the arc current and transports the air into the vicinity of the sidewall. Such an effect is an essential source of oxygen for the oxidation and contamination of the deposition layer during the WAAM process. Increasing the nozzle diameter can effectively lower air concentration near the build's sidewall, suggesting an enhancement in both shielding effectiveness and part quality. Our simulated outcomes are in reasonable consistency with experimental measurements, encompassing both arc plasma flow as observed through shadowgraphy imaging and the element distribution gauged via EDS line scans of the oxide layer formed during the build's deposition. [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]

The solar cell has become one of the options for a greener world. Various studies have been done to achieve a solar cell with high efficiency and reasonable price. This study's objective is to investigate how the thickness and base angle of the front layer affect the optical and electrical characteristics of Si-Based Solar cells. To accomplish this study, heterojunction solar cells using Al2O3/ITO as the double layer antireflection coating are analyzed using the Wafer Ray Tracer simulation by the PV Lighthouse. Al2O3 and ITO layers are used as a double anti-reflection coating (DLARC) in the light trapping strategy to support the reflection, absorption, and transmission (R, A and T) of the silicon solar cell. It acts to minimize reflectance and improves the overall efficiency of the solar cell. DLARC variation focuses on increasing absorption while decreasing reflection and transmission. The high refractive index of the hydrogenated a-Si (a-Si: H) emitter layer generates excessive reflection losses in SHJ solar cells making the silicon wafer have a low absorption efficiency. The DLARC thickness and base angle are varied as part of the simulation using the Wafer Ray Tracer by PV Lighthouse. The surface morphology of upright pyramid texture, height is 3.536 µm, texture base angle 54.74 °, and width 5 µm are used for reference scheme. Four schemes will be analyzed throughout this study along with the reference scheme. The result of this study is that Scheme 3 gives the optimum result with 99 % absorption, 21 % reflection and 67 % transmission. The goal of this study is to evaluate the impact of ARC thickness on optical and electrical characteristics. The best outcome is produced by varying the thickness and base angle of Scheme 3. The highest Jmax value, 0.3842 mA/cm2, is found in Scheme 3. [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]

Abstract In order to accurately extract the fault features of arc high impedance grounding of low‐voltage distribution lines and judge the fault feature types of arc high impedance grounding of low‐voltage distribution lines, a fault feature extraction method for arc high impedance grounding of low‐voltage distribution lines based on Bayesian network optimisation algorithm is proposed. According to the model of arc high impedance grounding fault based on Thomson’s principle, the parameter information of each transmission signal in arc high impedance grounding fault is extracted. Through the denoising method of arc high impedance grounding signal based on combined filter, the noise information of transmission signal in case of arc high impedance grounding fault is removed and the signal purity is improved. The detection and recognition method for fault characteristics of arc high impedance grounding of low‐voltage distribution lines based on Bayesian network optimisation algorithm is used to detect and judge the fault characteristics of the abnormal characteristics of the denoised transmission signal, and complete the fault feature extraction. After testing, this method can accurately and real‐time extract the fault characteristics of arc high impedance grounding of low‐voltage distribution lines, and has application value.

A more-electric aircraft refers to an aircraft whose secondary power is unified from the traditional multi-energy, such as mechanical energy, hydraulic energy, and pneumatic energy, to the electrical energy, which has the advantages of a simple system structure, high reliability, high maintainability, and high energy efficiency. The most advanced architecture of its power system is the 360–800 Hz variable frequency AC power supply and the 270 V high-voltage DC power supply, which have been applied in the Airbus A380, Boeing B787, F-22, and other more-electric aircraft. As power consumption increases, the power distribution, power network, and cable layout in a more-electric aircraft become more complex, and the probability of electrical faults such as short circuits increases. The arc generated by fault current not only severely affects the life, reliability, and safety of cable and electrical equipment but also limits the capacity expansion of an aviation power system and the improvement of flight performance. The circuit breaker in a more-electric aircraft is a key device for arc extinguishing. Analyzing the complex mechanism of the arc-discharging process in a circuit breaker helps improve the arc-extinguishing performance. To further promote research on the arc mechanism and extinguishing technology of circuit breakers in more-electric aircraft power systems, in this paper, the structure of civilian and military more-electric aircraft power systems and the difficulties in the electrical fault and protection are first analyzed. Then, the research status of the arc-extinguishing technology of the aviation variable frequency AC circuit breaker and the 270 V high-voltage DC circuit breaker are summarized. For an intermediate-frequency vacuum arc, the instantaneous input power inside the gap and at the anode increases with the current frequency, which indicates that the half-wave input power increases with the frequency and proves that the transition state arc is an important source of anode ablation during intermediate-frequency arcing. Under the same current condition, the frequency increases. On the one hand, when the value of di/dt increases, the arc-extinguishing ability decreases with increasing frequency. On the other hand, intensifying the skin effect leads to an increase in the arc center pressure, arc contraction, and magnetic field hysteresis, which is not conducive to arc extinguishing. In addition, the metal vapor density vaporized by droplets reduces the recovery strength of the dielectric after the current zero, which is not conducive to arc extinguishing. For the 270 V DC arc, air, nitrogen, helium, hydrogen, and other gas are presently used in aviation power systems, among which hydrogen is the research hotspot. Finally, future research trends of arc extinguishing technology for aviation circuit breakers are predicted.