Single Arc Research Articles

The development of an automated striking device for repeatable percussion strikes

Many high-quality directivity systems involve a single microphone arc which rotates around a sound source. Since multiple data captures are necessary as the arc rotates around a sound source, the source should emit the sound in a steady and repeatable way at all arc positions. To obtain directivity measurements of a struck percussion instrument, it is crucial to be able to strike the instrument during each microphone arc position as consistently as possible. However, a human player typically cannot strike the instrument in the exact same way for many consecutive measurements. To overcome the shortcomings of human players, an automatic striking device was developed to aid in the study of the directivity of percussion instruments. The device consists of a striking implement holder attached to a stepper motor that is controlled by an Arduino. The striking implement holder allows the user of the striking device to use different-sized mallets/drumsticks depending on the instrument that is being measured. The automatic striking device has been used to obtain directivity measurements on several instruments including a glockenspiel, cymbal, and drum. The details of the automatic striking device will be presented along with a subset of directivity results.

Single high-energy arc proton therapy with Bragg peak boost (SHARP).

Because of the co-location of critical organs at risk, base of skull tumours require steep dose gradients to achieve the prescribed dosimetric criteria. When available, proton beam therapy (PBT) is often considered a desirable modality for these cases, but in many instances, compromises in target coverage are still required to achieve critical organ at risk (OAR) tolerance doses. A number of techniques have been proposed to further improve the penumbra of PBT. In the current study, we propose a novel, collimator-free treatment planning technique that combines high-energy shoot-through proton beams with conventional Bragg peak spot placement. The small spot size of the high-energy pencil beams provides a sharp penumbra at the target boundary, and the Bragg peak spots provide a higher linear energy transfer (LET) boost to the target centre. Three base of skull chordoma patients were retrospectively planned with three different PBT treatment planning techniques: (1) conventional intensity-modulated proton therapy (IMPT); (2) high-energy proton arc therapy (HE-PAT); and (3) the novel technique combining HE-PAT and IMPT, referred to as single high-energy arc with Bragg peak boost (SHARP). The Monaco 6 treatment planning system was used. SHARP was found to improve the PBT penumbra in the plane perpendicular to the HE-PAT beams. Minimal penumbra differences were observed in the plane of the HE-PAT beams. SHARP reduced dose-averaged LET to surrounding organs at risk. A novel PBT treatment planning technique was successfully implemented. Initial results indicate the potential for SHARP to improve the penumbra of PBT treatments for base of skull tumours.

Experimental and Theoretical Realization of Morphology and Frequency Tuned Charge Transport Dynamics in Co-Zn Doped SrM Hexaferrite: Electrical, Impedance and Relaxation Realm

The present report comprehensively investigates the influence of sol-gel synthesized cobalt and zinc-substituted SrFe12O19 on the morphological, structural, dielectric, and electrical characteristics. XRD analysis revealed that the substituents successfully replaced Fe3+ ions, leading to the existence of magneto-plumbite structure of M-type hexaferrite in all synthesized samples with some minor traces of CoFe2O4 in Sr Co0.8Zn0.8Fe10.4O19. With increasing the substitution level, SEM micrographs exhibited the formation of grain clusters. The electrical parameters had been investigated in the 20 Hz to 2 MHz frequency range. In the low-frequency region, both dielectric constant and loss tangent decreased with Co-Zn substitution. Sr Co0.8Zn0.8Fe10.4O19 sample shows the minimum value of AC conductivity 3.95 × 10−5 Ω−1m−1 in the high-frequency region. Both the electric modulus and impedance spectra exhibit non-Debye behavior in all samples. The Cole-Cole plots ( M'' versus M') reveal the existence of a single semicircular arc in the x = 0.0 sample, caused by the grain boundary contribution.

The enigmatic enzyme 'amidoxime reducing component' of Lotus japonicus. Characterization, expression, activity in plant tissues, and proposed role as a nitric oxide-forming nitrite reductase.

Human mitochondria contain a molybdoprotein capable of reducing amidoximes using cytochrome b5/cytochrome b5 reductase (Cb/CbR). This 'amidoxime reducing component' (ARC) also reduces nitrite to nitric oxide (NO). In the plant kingdom, distinct functions have been suggested for ARCs. Thus, the single ARC of Chlamydomonas reinhardtii (crARC) reduces nitrite to NO by taking electrons from nitrate reductase (NR). Therefore, it was proposed that a dual NR/crARC system can generate NO under physiological conditions and the crARC was renamed to 'NO-forming nitrite reductase' (NOFNiR). In contrast to this, the two ARC enzymes from Arabidopsis thaliana were not found to produce NO in vitro at physiological nitrite concentrations, suggesting a different, as yet unknown, function in vascular plants. Here, we have investigated the two ARCs of Lotus japonicus (LjARCs) to shed light on this controversy and to examine, for the first time, the distribution of ARCs in plant tissues. The LjARCs are localized in the cytosol and their activities and catalytic efficiencies, which are much higher than those of A. thaliana, are consistent with a role as NOFNiR. LjARCs are prone to S-nitrosylation in vitro by S-nitrosoglutathione and this post-translational modification drastically inhibits their activities. The enzymes are mainly expressed in flowers, seeds and pods, but are absent in nodules. LjARCs are active with NR and Cb/CbR as electron-transferring systems. However, the LjNR mRNA levels in seeds and pods are negligible, whereas our proteomic analyses show that pods contain the two ARCs, Cb and CbR. We conclude that LjARCs may play a role as NOFNiR by receiving electrons from the Cb/CbR system but do not act in combination with NR.

An innovative pulsed current arc welding technology for armor steel: Processes, microstructure, and mechanical properties

This study presents a novel pulsed current arc welding technology, specifically pulsed current gas tungsten arc welding (PC-GTAW), single and double pulse gas metal arc welding (SP/DP-GMAW), and dual process welding (D-process). This study aims to investigate the effectiveness of these welding techniques for armor steel weldments. This research focused on investigating the welding processes, resulting microstructures, and mechanical properties of welded joints. Based on the macrography analysis, it was determined that the weldments exhibit no signs of porosity, inclusions, or inadequate penetration. This finding substantiates the optimum settings for the weldment production process. The weldment optical microstructure, fusion, and heat-affected zone were examined in the weld interface. The microstructural properties of the FZ include δ-ferrite, austenite, bainite, and acicular martensite. The HAZ has a bainite-untempered martensite microstructure. The chemical composition and variations across the weldment (base, weld and HAZ) were identified. The grain borders contained greater quantities of Cr, Ni, Mn, Si, and Mo than those of the grain cores. EBSD revealed average weld zone grain sizes of 17.7 µm, 32.6 µm, 30.8 µm, and 24.6 µm for PC-GTAW, SP-GMAW, DP-GMAW, and D-Process, respectively.Furthermore, the hardness measurements showed a progressive transition across different regions. Additionally, the D-Process-fabricated material exhibited a maximum ultimate tensile strength of 872 MPa and an elongation of 4%. The mechanical properties exhibited by this new process variant exceed those of other weldments, indicating its potential for fabricating armor steel. The impact toughness demonstrated superior performance in all the weldments. Within this context, the new use of pulsed current advanced welding methods has shown the ability to generate welded parts of exceptional quality.

A comprehensive study on structural, optical, electrical, and dielectric properties of PVA-PVP/Ag-TiO2 nanocomposites for dielectric capacitor applications

Nanocomposites made from polymers and nanoparticles (NPs) have a wide range of uses. Herein, the polymer nanocomposite electrolyte films were prepared by blending polyvinyl alcohol (PVA) and polyvinylpyrrolidone (PVP) with hybrid NPs of silver (Ag) and titanium dioxide (TiO2). The structural, optical, electrical, and dielectric properties of the resulting PVA-PVP/Ag-TiO2 nanocomposite electrolytes were analyzed. XRD analysis revealed that the PVA-PVP blend had a semicrystalline structure, and the addition of hybrid NPs reduced the crystallinity ratio. FTIR analysis showed that the intensity decreased as the content ratio of hybrid NPs increased. Optical measurements showed that the nanocomposite electrolyte samples' direct and indirect optical energy gap decreased with the increasing content of hybrid NPs. The electrical conductivity also increased with the hybrid NPs' content, likely due to the higher conductivity of the hybrid NPs compared to the polymer blend matrix's electrical conductivity. The dielectric constant (εr) and dielectric loss (εi) increased with the concentration of hybrid NPs at lower frequencies, indicating the polarization effects of space charges. The capacitance–frequency (C–f) and conductance–frequency (G/ω–f) curves of the prepared polymer nanocomposites exhibited a discernible enhancement correlating with the increased content of Ag-TiO2 nanofillers. The impedance spectroscopy data were analyzed using Nyquist plots, which showed a single semicircular arc whose radius of curvature decreased with increasing the hybrid NPs loading, indicating a decrease in the overall impedance of the nanocomposite electrolytes with the mixed NPs loading. The impedance reduction and dielectric feature increase were attributed to the interfacial polarization between the hybrid NPs and the polymeric matrix. These findings suggest that the PVA-PVP/Ag-TiO2 nanocomposite electrolytes could be used for thin-film dielectric capacitor applications.

The effects of Sr-substitution in Ba2SmTi2Nb3O15 ceramics: structural study, optical properties, and complex impedance spectroscopy.

Ceramics of (Ba1-xSrx)2SmTi2Nb3O15, denoted as BSxSTN (x = 0, 0.25 and 0.5), were synthesized by the conventional solid-state reactions route. The impact of Sr-substitution in Ba2SmTi2Nb3O15 ceramics on their structural, optical, and dielectric properties are investigated. The Rietveld method was employed to confirm the formation of tetragonal tungsten bronze with the P4bm space group, using X-ray diffraction data. The substitution of Ba by Sr resulted in a decrease in cell parameters, density, and the average crystallite size as determined by Scherrer's formula ranged from 29.4 to 32 nm. The compounds frequency-dependent dielectric properties were studied using complex impedance spectroscopy over a temperature range of 50 to 420 °C at different frequencies. Dielectric measurements revealed a high dielectric constant, and the compounds exhibited characteristics of diffuse ferroelectric behavior. As the Sr content increased, optical gap energy increases from 3.29 to 3.59 eV, diffusivity increased from 1.19 to 1.52, Curie temperature (Tc) decreased from 269 to 213 °C, and the dielectric loss at room temperature and 1 kHz significantly decreased from 3 × 10-3 to 7 × 10-4. The correlation between (Tc) and the off-center cationic displacement of Ti/Nb in the octahedral Ti/NbO6 was analyzed. Cole-Cole plots for each sample displayed a single semicircular arc, indicating the presence of a single relaxation process.

Efficient energy and memory storage capabilities in optimized BiFeO3/MnMoO4/NiFe2O4 triphasic composites for futuristic multistate devices.

The emergence of multiferroic materials particularly bismuth iron oxide (BiFeO3) with distinctive magnetoelectric, and high energy storage capabilities, present pivotal aspects for next-generation memory storage devices. However, intrinsically weak magnetoelectric coupling limits their widespread applications, that can be leap over by the integration of BiFeO3 with enriched ferroelectric, and ferro/ferrimagnetic materials. Here, a series (1 - x)[0.7BiFeO3 + 0.3MnMoO4] + xNiFe2O4 (x = 0.00, 0.03, 0.06, and 0.09) is synthesized via citrate-gel based self-ignition, and solid-state reaction routes. Phase purity and crystallinity of tri-phase composites with surfaces revealing random and arbitrarily shaped grains are assured by X-ray diffraction, and field emission scanning electron microscopy, respectively. Dielectric studies illustrated non-linear trend for broad range of frequencies as predicted by Maxwell-Wagner theory along with single semicircle arcs in Nyquist plots that exposes grain boundaries effect. An enriched 68.42% of ferroelectric efficiency is featured for x = 0.06 substitutional contents, while magnetic computations demonstrated improved saturation magnetization (M s), remanence magnetization (M r), and coercive applied magnetic field (H c) values as 5.87 emu g-1, 0.96 emu g-1, and 215.19 Oe, respectively for x = 0.09 phase-fraction. The intriguing linear trends of magnetoelectric coupling for all the compositions are corroborating them propitious contenders for futuristic multistate devices.

Effect of Low‐Temperature Stress on Electrical Impedance Spectroscopy Parameters of Rice Leaves at the Seedling Stage

The aim of this study was to detect the electrochemical characteristics of rice leaves under low‐temperature stress. This study uses the electrical impedance graph method and the electrolyte exostosis method under the condition of low‐temperature cold case study in the seedling stage of rice leaves, with a normal seedling stage of rice crops grown as controls. The shape of the electrical impedance map of rice leaves under low‐temperature stress and its change with the increase of low‐temperature stress were studied, and the change trend of electrical impedance map parameters with the increase of low‐temperature stress was statistically analyzed. At the same time, the two detection methods are discussed to establish the correlation. The results showed that the electrical impedance pattern was a complete, symmetrical, single half arc with rice leaves subjected to reversible damage. The left side of the arc starts to disappear with an irreversible injury. Rice tended to die when the arc on the right side of the impedance spectrum began to scatter. Moreover, the change in the electrical impedance spectrum was consistent with that of relative conductivity. When the rice was not dead, the extracellular resistance and relaxation time of leaves decreased with the increase of stress degree, and intracellular resistance increased. Indicating the electrical impedance spectroscopy (EIS) can be employed as a nondestructive testing method to detect physiological characteristics of rice leaves under low‐temperature stress.

Treatment Optimization in Linac-Based SBRT for Localized Prostate Cancer: A Single-Arc versus Dual-Arc Plan Comparison.

This study aimed to comprehensively present data on treatment optimization in linac-based SBRT for localized prostate cancer at a single institution. Moreover, the dosimetric quality and treatment efficiency of single-arc (SA) versus dual-arc (DA) VMAT planning and delivery approaches were compared. Re-optimization was performed on twenty low-to-intermediate-risk- (36.25 Gy in 5 fractions) and twenty high-risk (42.7 Gy in 7 fractions) prostate plans initially administered with the DA FFF-VMAT technique in 2021. An SA approach was adopted, incorporating new optimization parameters based on increased planning and clinical experience. Analysis included target coverage, organ-at-risk (OAR) sparing, treatment delivery time, and the pre-treatment verification's gamma analysis-passing ratio. The SA optimization technique has consistently produced superior plans. Rectum and bladder mean doses were significantly reduced, and comparable target coverage and homogeneity were achieved in order to maintain a urethra protection strategy. The mean SA treatment delivery time was reduced by 22%; the mean monitor units increased due to higher plan complexity; and dose measurements demonstrated optimal agreement with calculations. The substantial reduction in treatment delivery time decreased the probability of prostate motion beyond the applied margins, suggesting potential decrease in treatment-related toxicity and improved target coverage in prostate SBRT. Further investigations are warranted to assess the long-term clinical outcomes.

A multi-centre stereotactic radiosurgery planning study of multiple brain metastases using isocentric linear accelerators with 5 and 2.5mm width multi-leaf collimators, CyberKnife and Gamma Knife.

This study compared plans of high definition (HD), 2.5 mm width multi-leaf collimator (MLC), to standard, 5 mm width, isocentric linear accelerator (linacs), CyberKnife (CK), and Gamma Knife (GK) for stereotactic radiosurgery (SRS) techniques on multiple brain metastases. Eleven patients undergoing SRS for multiple brain metastases were chosen. Targets and organs at risk (OARs) were delineated and optimized SRS plans were generated and compared. The linacs delivered similar conformity index (CI) values, but the gradient index (GI) for HD MLCs was significantly lower (P-value <.001). Half the OARs received significantly lower dose using HD MLCs. CK delivered a significantly lower CI than HD MLC linac (P-value <.001), but a significantly higher GI (P-value <.001). CI was significantly improved with the HD MLC linac compared to GK (P-value = 4.591 × 10-3), however, GK delivered a significantly lower GI (P-value <.001). OAR dose sparing was similar for the HD MLC TL, CK, and GK. Comparing linacs for SRS, the preferred choice is HD MLCs. Similar results were achieved with the HD MLC linac, CK, or GK, with each delivering significant improvements in different aspects of plan quality. This article is the first to compare HD and standard width MLC linac plans using a combination of single isocentre volumetric modulated arc therapy and multi-isocentric dynamic conformal arc plans as required, which is a more clinically relevant assessment. Furthermore, it compares these plans with CK and GK, assessing the relative merits of each technique.

Hydrothermal vent fauna of the western Pacific Ocean: Distribution patterns and biogeographic networks

AbstractAimDeep‐sea hydrothermal vent habitats support a low‐diversity fauna in which most species are unique to the ecosystem. To inform conservation planning around this vulnerable marine ecosystem, we examine species distributions over a wide area to assess the underlying beta‐diversity components and to examine biogeographic patterns. We assess the concept of a highly connected fauna that would repopulate areas of local extinction from distal locations.LocationWestern Pacific Ocean from Japan to New Zealand.MethodsWe assemble a database of 295 confirmed species records for 11 western Pacific vent systems. The SET beta‐diversity framework supports query of the distribution of pairwise pattern components in comparisons among vent systems. We build a network based in graph theory to examine connectivity among vent systems based on shared species similarity. A bipartite network revealed the relative role of each species in linkages among vent system nodes. We assess the importance of sampling bias and distance between systems.ResultsOverall, two‐thirds of the taxa are restricted to a single basin or arc. The Mariana Trough system has the highest corrected weighted endemism for vent‐specific species, followed by that of the Okinawa Trough. Species replacement is the dominant feature of beta‐diversity. Eleven vent systems form seven network modules with stronger connectivity in the Southwest than Northwest Pacific. The Manus Basin vent system emerges as a network ‘hub’ reflecting its central geographic near the equator.Main ConclusionTwo western Pacific biogeographic provinces arise, north and south of the equator that few species transcend. Local and regional conservation plans should consider the low network connectivity and high system endemism in management of hydrothermal vent ecosystems in the event of seabed mining. Species recruitment is unlikely to transcend vent system boundaries. We identify Okinawa Trough, Mariana Trough, Manus Basin, Feni‐Tabar Arc and Kermadec Arc for development of conservation plans that initiate or expand protection.

Study of arc behavior and machining effects of the novel magnetic field assisted blasting erosion arc machining method

Electrical Arc Machining (EAM) is a high-efficiency, cost-effective method for machining electrical conductive materials especially difficult-to-cut ones. Because this thermal process relies on high-density energy to melt and remove material, effective arc control is crucial to maintain stable machining without overheating the workpiece. However, due to the limited discharge gap, it is difficult for the existing arc breaking methods to manage the arc plasma in a timely and uniform manner. This paper proposes a novel method named Magnetic Field Assisted Blasting Erosion Arc Machining (M-BEAM). This method introduces a magnetic field to enhance the control effect on arc plasma by directly influencing charged particles. Initially, the arc control and material removal mechanisms were revealed through an analysis and experiments of single arc discharge. Both simulated particle trajectory and high-speed photographs demonstrated that the arc plasma deflects much earlier in the magnetic field than that of traditional BEAM. Moreover, the expulsion effect of molten metal was significantly improved, resulting in a larger volume crater. Building on this, the magnetic-assisted arc control mechanism was utilized to enhance the performance of BEAM. Experimental results indicate that compared with traditional BEAM, Magnetic Field assisted BEAM increases its Material Removal Rate (MRR) by 10.09% while significantly reducing the Tool Wear Ratio (TWR) by 29.02%. Additionally, surface roughness (Sa) is decreased by 47.73%, and the thickness of the recast layer is decreased by 78.54%. Therefore, M-BEAM can further improve the machining performance and build a good foundation for subsequent machining.

P086 - Dosimetric comparison of imrt vs. vmat - Single arc, dual arc and combination of dual and single arc plans for high risk prostate cancers

P086 - Dosimetric comparison of imrt vs. vmat - Single arc, dual arc and combination of dual and single arc plans for high risk prostate cancers

Modeling and simulation study on the ablation characteristics of DC contactor contact

The DC contactor can frequently break the high current control circuit, and the arc motion characteristic in the current breaking process is closely related to its electrical life and reliability. In this paper, a three-dimensional magnetohydrodynamic arc model of the DC contactor considering contact motion and external circuit characteristics is established. On this basis, the influence of the vapor produced by the contact ablation on the arc behavior is studied, and the ablation rate of the cathode in a single breaking process is calculated. The results show that the arc temperature is reduced, the motion speed is slowed down, and the arc burning time is shortened due to the presence of copper vapor produced by ablation. The ablation rate of the cathode during a single arc is 8.9 µg/C.

Studies on Structural and Ionic Conductivity of Li2NiP2O7

In this study, a solid-state method was employed to synthesize Li2NiP2O7. By analyzing the X-ray diffraction (XRD) data, the existence of a monoclinic-type structure with a single phase was verified using Rietveld refinement. The surface morphology of the samples was examined using scanning electron microscopy (SEM). Moreover, the electrical properties were measured using complex impedance spectroscopy (CIS) as a function of frequency (10 Hz to 7 MHz) at various temperatures (553–653 K). Impedance analysis was performed using an equivalent circuit model, which indicated the presence of a single semicircular arc. In addition, we investigated the intricate relationships between the electrical and structural properties of the materials, as well as the transport phenomena. Specifically, we explored the ion-hopping mechanism, which is governed by the movement of Li+ cations within the Li2NiP2O7 structure and is responsible for the conduction mechanism. Finally, it is important to note that our exploration of the Li2NiP2O7 compound revealed a noteworthy electrical conductivity of σ 573 = 1.23*10−2 Ω−1 cm−1. These findings underscore the potential suitability of this material for application as a promising cathode material for recheagable batteries.

Locoregional breast radiotherapy including IMN: optimizing the dose distribution using an automated non-coplanar VMAT-technique

Background Volumetric Modulated Arc Therapy (VMAT) offers better conformity, homogeneity and sparing of the heart and ipsilateral lung for locoregional radiotherapy in left-sided breast cancer compared to three-dimensional conformal radiotherapy (3D-CRT). However, conventional coplanar VMAT (cVMAT) can result in higher doses to the normal tissue on the contralateral side. This study investigates a non-coplanar VMAT-technique (ncVMAT) to mitigate this issue. Material and methods CT series of 20 left sided breast cancer patients were included for planning of locoregional breast radiotherapy including internal mammary nodes (IMN). Three treatment plans; 3D-CRT, cVMAT and ncVMAT, were generated for each patient with a prescription dose of 40.05 Gy in 15 fractions. Both VMAT-techniques consisted of a single arc in the axial plane, while ncVMAT included an additional arc in the sagittal plane. All plans were optimized to cover the clinical target volume (CTV) by 38.05 Gy for the breast and 36.05 Gy for lymph nodes, with as low as possible dose to organs at risk. Results Full CTV coverage was achieved for all plans. Both cVMAT and ncVMAT delivered more conformal and homogeneous target doses than 3D-CRT. Doses to the heart and ipsilateral lung were significantly lower with ncVMAT compared to both cVMAT and 3D-CRT. ncVMAT reduced doses to both the contralateral breast and lung compared to cVMAT and achieved levels similar to 3D-CRT for the contralateral breast and moderately higher doses for the contralateral lung. Delivery of high doses (>30 Gy) to the contralateral side was completely avoided with ncVMAT, contrary to the results for cVMAT and 3D-CRT. Conclusion ncVMAT reduced doses to the heart and ipsilateral lung as compared to both cVMAT and 3D-CRT. All contralateral dose metrics were reduced with the novel ncVMAT technique compared to cVMAT, and the mean contralateral breast doses were similar to 3D-CRT.

Hypofractionated Radiotherapy for Prostate Cancer (HRT20) Trial: Results

Radiotherapy is a definitive standard treatment for men with localized prostate cancer. Improvements in technology allow higher doses of radiation delivered to the prostate in less days, with lower doses to surrounding healthy tissues trying to reduce side effects. Several studies demonstrated that hypofractionated radiotherapy of 60 Gy is non-inferior to conventional radiotherapy fractionation. To report the first results in toxicity and biochemical relapse free survival of HRT20 trial after 5 years of recruitment. The HRT20 trial is registered (NCT03851926). A prospective observational study enrolled 298 men with localized prostate cancer (pT1b-T3aN0M0) started in October 2016. Median age was 75 (53-91). Median PSA was 14.5ng/ml. Using NCCN classification: 12,6% were low risk, 50.5% were intermediate and 36.9 % were high risk patients. The median duration of the treatment was 30 days (23-41) The clinical target volume (CTV) consisted of the prostate and seminal vesicles when affected. The CTV-planning target volume (PTV) margin was 0.8 cm. The primary end point evaluated assessed by CTCAE 4.0 was related later adverse events and the second end point was biochemical relapse free survival by Phoenix definition. WMAT plans calculations were carried out using the Monaco TPS version 5.10 based on a single arc arrangement. Univariate and multivariate logistic analyses were carried out. After median follow up of 56 months. The 5-year incidence rates of grade 2 and 3 late gastrointestinal toxicities were 6.3% and 3.1%, respectively, and those of grade 2 and 3 late genitourinary toxicities were 7.9% and 1%, respectively. PTV volume was found to be correlated with late rectal bleeding (p = 0.02). Also, urinary tract obstruction was correlated with PTV volume. The proportion of patients who were biochemical failure free at 5 years was 88·3% (95% CI 86·0-90·2) Multivariate analysis indicated that risk stage (p = 0.03) and number of positive needles biopsy cores (p = 0.02) were prognostic factor for biochemical relapse-free survival rates. The findings of this study indicate that hypofractionated is well tolerated and it is associated with good 5-years tumor-control outcomes in patients with localized prostate cancer. Long-term follow-up continues.

Numerical study on weld pool behaviors and keyhole dynamics in magnetic-field-assisted laser-arc hybrid welding of aluminum alloy

External magnetic field has been employed to improve appearance and suppress defects in the single laser or arc welding, and its physical mechanism in magnetic-field-assisted single laser or arc welding has been clearly clarified. However, few studies on the physical processes in magnetic-field-assisted laser-arc hybrid welding (MFA-LAHW) are conducted and its influencing mechanism is unclear. In this research, a comprehensive three-dimension numerical model is established to investigate the keyhole dynamics and weld pool behaviors in MFA-LAHW under the effect of different magnetic flux density. The results suggest that the interaction between a lower magnetic flux density (≤30 mT) and welding current is induced due to the existence of arc. Compared to the magnetic-field-assisted laser beam welding (MFA-LBW), this interaction induces a stronger Lorentz force up to the order of magnitude of 105 N/m3. The weld pool width is reduced while its length and height are increased because the Lorentz force facilitates the backward flow of thermal fluid, increasing the heat transfer from the keyhole and droplet to the rear weld pool edge. Moreover, the steady magnetic field improves the keyhole stability. The deform on keyhole rear wall brought by the droplet and vortex is suppressed, and keyhole size is widened under steady magnetic field, which reduced keyhole collapse. Furthermore, the comparative analysis with the case in MFA-LBW is carried out and the MFA-LAHW is verified to be more valuable for medium-thickness aluminum alloy. This work provides the underlying physics understanding of MFA-LAHW, which will broaden the application value of LAHW.

Provenance of the Nb-rich bauxite and Li-rich claystone at the base of the Heshan Formation in Pingguo, Guangxi, SW China: Constrained by U–Pb ages and trace element contents of detrital zircon

The base of the Upper Permian Heshan Formation in Pingguo County, Guangxi Province, SW China, can be divided into two layers: a lower Nb-rich bauxite layer and an upper Li-rich claystone layer. The sources of these layers may have played a critical role in their formation. Detrital zircon provenance analysis is an effective method for identifying sediment provenance; however, it has not been applied previously to the Nb-rich bauxite and Li-rich claystone, thus limiting our knowledge of the sources of these two layers. Detrital zircons from the bauxite and the claystone layers yield a single age peak at ∼ 260 Ma, which is consistent with the age of the Emeishan Large Igneous Province (LIP; 263–257 Ma) and the Permian Palaeo-Tethyan magmatic arcs (300–260 Ma). In contrast, detrital zircons from the two layers yield different trace element signatures. Yttrium and Hf contents and U/Yb ratios of detrital zircon grains from the bauxite layer overlap with those of continental and oceanic crust and have similar Hf/Th, Th/Nb, Th/U, and Nb/Hf ratios to those of zircons of within-plate and magmatic arc origins. These results indicate that the bauxite was sourced from volcanic rocks or ash related to the Emeishan LIP and the Permian Palaeo-Tethyan magmatic arcs. However, detrital zircons from the claystone have similar Hf/Th, Th/Nb, Th/U, and Nb/Hf ratios to only those of zircon from magmatic arcs, suggesting a single Permian Palaeo-Tethyan magmatic arc source. Thus, our results reveal an abrupt change in the provenance of zircons at the base of the Heshan Formation. The lower Nb-rich bauxite layer was derived from the weathering of volcanic rocks or ash related to the Emeishan LIP and the Permian Palaeo-Tethyan magmatic arcs, whereas the upper Li-rich claystone layer was derived principally from the weathering of volcanic ash related to the Permian Palaeo-Tethyan magmatic arcs. Since Nb is an immobile element, volcanic rocks/ash related to the Emeishan LIP and the Permian magmatic arc could represent a source for bauxite and Nb. In contrast, Li is chemically highly mobile in the Earth’s surface environment and its origin cannot be constrained easily, further work is needed to identify the sources of Li.