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Surface mechanical strengthening is an effective way to improve the fatigue performance, among which surface rolling has been vastly utilized for its significant enhancement in fatigue strength. However, traditional rolling process is only suitable for components with rotational symmetry, limiting its application. Herein, a newly developed technology named "spinning rolling (SR)" was developed to strengthen the surfaces of platy components. A common Al alloy, 7075, was selected for verifying the effect. It is found that compared with the most popular technology, shot peening (SP), SR can provide deeper and higher residual stress, lower surface roughness, and comparable hardening layer, and consequently, significantly higher fatigue lives. Accordingly, there is a transition in the fatigue crack source from point‐like to line‐like, confirming a strong crack propagation resistance along depth direction. This study indicates the advantages of the SR technology, providing a greater resistance against fatigue damage of platy components. Highlights: We developed a new surface strengthening technology—spinning rolling (SR), which has wider applicability and better fatigue life extension effect.The fatigue lives of 7075 aluminum alloy plates processed by SR are highly improved by even one order of magnitude at the same stress amplitude.There is a transition in the fatigue crack source from point‐like to line‐like, confirming a strong crack propagation resistance along depth direction due to SR. [ABSTRACT FROM AUTHOR]

Cold spray (CS) has emerged as an appealing additive manufacturing (AM) technique for producing or repairing individual components or entire structures. Compared to fusion-based AM technologies, cold spray additive manufacturing (CSAM) offers distinct advantages in the fabrication of components, while avoiding some melting/solidification-related issues such as phase transformation and oxidation. It involves intricate processes that pose significant challenges for numerical modeling, particularly when simulating the entire process at a large scale. The smoothed particle hydrodynamics (SPH) method is highly suitable for handling large material deformations due to its Lagrangian and meshless nature. In this work, we develop an enhanced SPH method to conduct large-scale simulations of CSAM with different powder sizes, morphologies, and distributions. A modified material model has been incorporated to accurately capture the strain-rate hardening effects during the plastic stage. The computational scale is greatly improved by using a Message Passing Interface (MPI) based framework, enabling the simulation of approximately ten million SPH particles. To the authors' knowledge, this study marks the first attempt to numerically reproduce the entire process of CSAM with real powder sizes and distributions. Experimental data measured for a wide range of powder velocities are used to validate the simulation results and assess the prediction accuracy. Subsequently, we comparatively study the bonding mechanisms of powders with the same or different sizes, while also identifying a four-stage coating process. The effects of powder morphology on the bonding process are thoroughly investigated. A large-scale CSAM process is finally reproduced to demonstrate the capability of the present meshless scheme, and mechanisms of pore formation are analyzed, providing valuable insights for practical engineering applications. [ABSTRACT FROM AUTHOR]

With the continuous downsizing of solder joints, the influence of the grain characteristics of the under bump metallization (UBMs) on the interfacial reaction is exposed. In this paper, the effect of grain characteristics of Cu UBM on the growth of interfacial intermetallic compounds and the formation of Kirkendall voids in Cu/Sn/Cu micro solder joints during isothermal aging at 150 °C was investigated. Electroplated polycrystalline Cu (EP-Cu), (111) single crystal Cu ((111) Cu), and (111) nano-twinned Cu ((111) nt-Cu) were selected as UBMs. After reflow soldering, the Cu6Sn5 grains formed on (111) nt-Cu were near to the orientation (2 1 - 1 - 3) , while those were randomly formed on both EP-Cu and (111) Cu. During isothermal aging, the Cu6Sn5 grains exhibited the highest growth rate on (111) nt-Cu UBM, and the slowest growth rate on (111) Cu UBM, due to the differing number of diffusion routes among the three Cu UBMs with distinct grain characteristics. Furthermore, no Kirkendall voids were detected on the (111) Cu UBM, however, a significant number of Kirkendall voids were identified on the (111) nt-Cu UBM, which can be attributed to the diffusion path and impurities present in the three Cu UBMs. The results will offer theoretical and practical recommendations for the selection of Cu UBMs for micro solder joints in 3D packaging interconnection technology. [ABSTRACT FROM AUTHOR]

This study analyzed physiological and molecular characteristics associated with the resistance to aging or anti-senescence in Camellia oleifera Abel. Trees over 100 years old (ancient trees) were compared with those about 30 years old (mature trees). Total chlorophylls, chlorophyll a/b ratio, and hydrogen peroxide concentrations in ancient tree leaves were significantly higher than in their counterparts. Significantly higher activities of superoxide dismutase, peroxidase, and catalase were detected in ancient tree leaves. Nine Chl a/b-binding protein genes, 15 antioxidant enzyme genes, 21 hormone-related genes, and 301 stress-related genes were upregulated, and 42 protein-degradation genes were downregulated in ancient tree leaves. By increasing chlorophyll content and antioxidant enzyme activities and regulating the ageing-related genes expression, ancient C. oleifera leaves maintained remarkable vitality. Although further research is needed, our study may shed some light on how ancient C. oleifera trees can resist ageing and sustain their healthy growth. [ABSTRACT FROM AUTHOR]

The corotation electric field driving the plasmasphere to corotate with the Earth body is important in establishing the topology of the inner magnetosphere and is usually calculated by assuming a 24 h corotation period. However, studies have found that a plasmasphere corotation lag exists, suggesting an overestimation of the electric field driving the plasmasphere to rotate with the planet in previous calculations. In this study, we use electric field measurements from the Van Allen Probes mission from 2012 to 2018 to obtain the distribution of the large-scale electric field in the inner magnetosphere. A new method is developed to extract plasmaspheric rotation information from electric field measurements. Our results show that the electric field driving the plasmaspheric rotation varies with magnetic activity, decreasing with increasing Kp index. It is thus suggested that the corotation lag of the plasmasphere is more significant during magnetically active periods. [ABSTRACT FROM AUTHOR]

Goos-Hänchen (GH) shift, an interference phenomenon describing the lateral shift of the reflected beam along the interface during total internal reflection, has attracted great interests in the field of quantum transport in two-dimensional materials. In particular, the GH effect generates a novel pseudospin-dependent scattering effect in graphene, which in turn results in an 8 e 2 / h conductance step in the bipolar junctions. Here, we reveal that a barrier region with effective barrier strength χ can greatly enrich the GH effect in graphene junctions. In contrast to the conventional case where the negative shift is allowed only in the p - n junction, the thin barrier enables both negative and positive spatial shifts in p I n and n I n junctions, where I represents the barrier region. More interestingly, the lowest channel degeneracy can be efficiently varied by tuning χ in both the symmetric p I n I p and the asymmetric pn I p junctions, leading to a highly controllable switch that switches the conductance between 8 e 2 / h and 4 e 2 / h. These results advance the knowledge of GH effects in electronic materials and suggest experimental avenues for its observation and manipulation. [ABSTRACT FROM AUTHOR]

Well-developed micro and mesoporous activated carbon fibers (ACFs) with fiber structure were prepared from tissue by CO2 activation. The XRD patterns and Raman spectrum indicated ACFs had a graphitic and amorphous structure. The SEM results indicated that the sample exhibited fiber structure with lots of mesoporous, with an average pore size of 2-5 nm. The specific surface area of 1517 m²/g, micro surface area of 412.9 m²/g, and total pore volume of 1.194 cm³/g were obtained at 900°C with CO2 activation for 2 hours. ACFs showed relatively high methylene blue adsorption properties with an equilibrium adsorption capacity of 526 mg/g. The kinetic model of the Pseudo-second-order equation was more suitable for MB adsorption than the Pseudo-first-order equation and Intraparticle diffusion kinetics, with a high correlation coefficient value (R>0.999). The present research provided a new idea of bionics for the manufacture of ACFs and brought forward a creative prospect for achieving energy-related CO2 emissions to net-zero and mitigating global warming. [ABSTRACT FROM AUTHOR]

We systematically compare the temporal and spectral properties of 53 supernova (SN)-associated and 15 kilonova (KN)-associated gamma-ray bursts (GRBs). We find that the spectral parameters of both types of GRBs are identically and lognormally distributed, consistent with those normal GRBs. The bolometric luminosities of SN/GRBs and KN/GRBs have a triple form, with the corresponding break luminosities of SN/GRBs are roughly two orders of magnitude larger than those of KN/GRBs. We build the power-law relations between the spectral lag and the luminosity of prompt γ-rays with indices of −1.43 ± 0.33 for SN/GRBs and −2.17 ± 0.57 for KN/GRBs in the laboratory frame, which are respectively coincident with the rest-frame values. We verify that both SN/GRBs and KN/GRBs comply with their own Amati relations that match those of long and short GRBs, respectively. Analysing X-ray afterglows with good plateau segments, we build the power-law relations between the X-ray luminosity and the plateau time with an index of −1.12 ± 0.17 for KN/GRBs and −1.08 ± 0.22 for SN/GRBs, which can be well explained by the relativistic shock driven by an energy injection. The plots of luminosity-lag, Amati relation, and luminosity-time show heavy overlap between the two types of GRBs, implying that they might share the same radiation mechanism despite originating from different progenitors or central engines. [ABSTRACT FROM AUTHOR]

We investigated photo-induced effects in Ge-Ga-Se films. It was found that, thermal annealing causes the increase of the bandgap in the as-prepared films, and all three annealed films show photodarkening (PD) behavior with light illumination but the change of optical bandgap is minimum in Ge25 film. Such PD behavior can be recovered by reannealing of the film. The kinetic process of Tf/Ti exhibits part recovering of PD during the cycle of laser on and off. Moreover, no obvious structural change can be observed in the Raman spectra of the films at different states, especially in that of Ge25 film. [ABSTRACT FROM AUTHOR]

Various modeling studies have examined the climatic effects of either the Central American Seaway or the Indonesian seaway. The co‐existence of these two tropical seaways may have a greater influence than the existence of a single seaway. Although the dual seaway situation is closer to that reconstructed during Miocene/Pliocene, relevant studies remain scarce. Here, we investigate the co‐effects of dual tropical seaway changes on the Pacific circulation through a set of sensitivity experiments. Our results show that the combined shallow opening of tropical seaways can generate an active Pacific meridional overturning circulation and maintain strong upwelling conditions along the equatorial Pacific, which may have helped favor a "biogenic bloom" during the late Miocene and early Pliocene. Moreover, the logically successive closure of the tropical seaways can provide patterns of zonal sea surface temperature gradients that are similar to those recorded in the equatorial Pacific from the late Miocene to the Pliocene. Plain Language Summary: During the late Miocene and the Pliocene, changes in the Central American and the Indonesian seaways geometry are very important for ocean circulation and global climate. Various modelling studies have examined the separate effects of these two tropical seaways, especially their link to the onset of the Northern Hemisphere ice sheets through changes in the Atlantic meridional overturning circulation and associated heat and moisture transport. Although the existence of dual tropical seaways is closer to the reality, there are very scarce modelling studies exploring the co‐effects of dual tropical seaway changes, especially on the Pacific ocean circulation. Here we provide the results of modelling study on this issue. Our results show that the combined shallow opening of tropical ways can generate an active Pacific meridional overturning circulation (i.e., absent in modern conditions) by which the meridional and zonal sea surface temperature gradient in the Pacific largely reduce. In contrast, a deeper opening of tropical seaways can not produce these changes in the Pacific ocean circulation. This study provides insights into and a better understanding of the role of tropical seaways in shaping the Pacific climate and highlights the importance of the sill depth of each seaway. Key Points: The co‐effects of opening of two tropical seaways on the Pacific circulation are investigated with climate modelShallow opening of tropical seaways can generate an active Pacific meridional overturning circulation, whilst a deeper condition can notThe stepwise closure of the tropical seaways can provide similar‐to‐record patterns of zonal sea surface temperature gradients [ABSTRACT FROM AUTHOR]

To solve the problem of slow solidification of large ingots and the difficulty of eliminating internal shrinkage, a cold steel bar was fed into the molten steel during the solidification process after the completion of casting to affect the solidification process. Different cooling and solidification schemes for 60-ton 16-angle ingots were simulated by the finite element simulation software PROCAST. The simulation results show that the insertion of cold steel rods can shorten the full solidification time of the ingot. It is beneficial to improve the concentrated shrinkage in the central region under the conventional cooling scheme; in terms of the cold steel addition method, the decentralized addition of cold steel is more effective in improving the internal quality of the ingot. [ABSTRACT FROM AUTHOR]

Hydraulic rotary drilling can offer the essential information and core samplesa for the researches on solid earth. Recording the factual field drilling data and analyzing the hydraulic rotary coring process are challenging yet promising to utilize the massive drilling information in geophysics and geology. This paper adopts the drilling process monitoring (DPM) technique and records the four parameters of displacement, thrust pressure, upward pressure, and rotation speed in real-time series for profiling the siliciclastic sedimentary rocks along 108 m deep drillhole. The digitalization results with 107 linear zones represent the spatial distribution of drilled geomaterials including superficial deposits (fill, loess, gravelly soil), mudstone, silty mudstone, gritstone, and fine sandstone. The constant drilling speeds varying from 0.018 to 1.905 m/min present the in-situ coring resistance of drilled geomaterials. Furthermore, the constant drilling speeds can identify the strength quality of soils to hard rocks. The thickness distributions of the six basic strength quality grades are presented for all the sedimentary rocks and each individual type of the seven soil and rocks. The in-situ strength profile determined in this paper can be used to assess and evaluate the in-situ mechanical behavior of geomaterial along the drillhole and can provide a new mechanical-based assessment for determining the spatial distribution of geological strata and structures in subsurface. They are important since the same stratum at different depths can have different mechanical behavior. The results provide a novel quantitative measurement for continuously in-situ mechanical profiling by digital drilling data. The findings of the paper can offer a new and effective method for refinement and upgrading of in-situ ground investigation, and can provide researchers and engineers with a novel tool and valuable reference to digitize and utilize factual data of current drilling projects. [ABSTRACT FROM AUTHOR]

The post-stall flow control using compliant flags of varying thickness and length, placed upstream a NACA0012 airfoil, was shown to be possible at an airfoil chord Reynolds number of 100,000. The flag wakes produced substantial increase in the stall angle and the maximum lift coefficient of the airfoil placed at optimal cross-stream locations from the wake centerline. Oscillating flags could generate periodic wakes with better spanwise coherence than the stationary bluff body. This resulted in the excitation, formation and shedding of the leading-edge vortices periodically, providing mean lift enhancement. There is an optimal range of the flag mass ratio for which the flag frequency coincides with the natural frequency of the vortex shedding instability or its subharmonic of the baseline airfoil wake. The flag dimensionless frequency is a function of the mass ratio only, which can be predicted by a reduced order model in the limit of very large mass ratio and by using the modified free-streamline theory for the separated flow. There is also an optimal range of the flag dimensionless frequency. [ABSTRACT FROM AUTHOR]

Getting Ni-WC composite coatings with different rare earth CeO2 additions on the substrate of 45 steel by induction heating; testing the surface hardness and cross-section microhardness of the coatings with Rockwell hardness tester and microhardness tester; meanwhile analyzing the microstructure and WC morphology of the coatings by scanning electron microscopy (SEM), in order to find the best amount of CeO2 in the coatings. The results show that the 0,5 / % content of CeO2 helps to improve the interfusion bonding between the coating and the substrate, and to refine the grain size, homogenize the composition and increase the hardness of the coating. [ABSTRACT FROM AUTHOR]

We have measured optical properties of GexGa4S96-x (x=22.5, 27, 30, 33.3 and 36) glasses including optical bandgap Eg, hardness, linear and nonlinear refractive index and laser damage threshold. We found that, both Eg and laser damage threshold exhibit maximum values in Ge30Ga4S66 glass, linear refractive index increases with increasing Ge content, but nonlinear refractive index has a minimum in Ge30Ga4S66, and their correlation can be well described by the Miller's rule. We conclude that, Ge30Ga4S66 glass with chemically stoichiometric composition might be ideal for the chalcogenide-based optical amplifiers since it has reasonable optical nonlinearity, and high figure of merit (FOM) and laser damage threshold. [ABSTRACT FROM AUTHOR]

The primary objective of this work is to provide connection-level force-deformation response appropriate for standard cold-formed steel (CFS) framed steel sheet sheathed shear walls under cyclic loads. Common CFS framing designs increasingly are exploring thicker framing options so that walls can meet gravity demands, overturning demands, and seismic overstrength requirements. For the seismic performance of self-drilling screw-fastened steel sheet sheathed shear walls, the cyclic nonlinear response of the screw-fastened connection is particularly important and should incorporate the impact of shear buckling of the steel sheet on the strength and ductility of the connection. Minimal cyclic connection-level shear test data exist, especially for combinations of screw-fastened thin steel sheet and thick framing steel. A unique lap shear test following current test standards was proposed to elucidate and characterize the cyclic screw-fastened connection behavior. An asymmetric cyclic loading protocol was selected with a small displacement applied in the direction that buckles the thin steel sheet, followed by progressively larger displacements in the opposite direction. A total of 93 tests were conducted, and characterization of the observed cyclic connection response with a multilinear backbone curve appropriate for use in models is provided. Connection strength is sensitive to whether the thin steel sheet ply is buckling away from or toward the fastener head in some test series. Performance of the screw shear strength as per the standard's provisions is evaluated. The work is intended to provide critical missing information for CFS framed steel sheet sheathed shear walls for use in both simulation and design. [ABSTRACT FROM AUTHOR]

Owing to a lack of multiple components of prompt γ-ray emissions in short gamma-ray bursts (sGRBs), how these distinct components are correlated remains unclear. In this paper we investigate the spectral and temporal properties of precursors, main peaks, and extended emissions in 26 sGRBs including GRB 170817A. It has been found that peak energies (Ep) in each pulse are uncorrelated with the pulse duration (tdur). Meanwhile, we find that there is no obvious correlation between peak energy and energy fluence. Interestingly, there is no obvious spectral evolution from earlier precursors to later extended emissions in view of the correlations of tdur with either the Ep or the low-energy spectrum index, α. A power-law correlation between the average flux (Fp) and the energy fluence (Sγ), log Fp = (0.62 ± 0.07) log Sγ + (0.27 ± 0.07), is found to exist in the individual segments instead of mean peaks. Furthermore, we also find that the main peaks are on average brighter than the precursors or the extend emissions by about one order of magnitude. On the basis of all the above analyses, we can conclude that three emissive components could share the same radiation mechanisms, but that they might be dominated by diverse physical processes. [ABSTRACT FROM AUTHOR]

With the rapid development of the global economy, the world energy consumption is increasing day by day. Mankind is facing the problem of energy shortage. Energy conservation and emission reduction has become the focus of countries all over the world. In order to study the influence of building envelope on building energy efficiency in severe cold area, the sensitivity analysis is used to analyze the influence relationship between building envelope and building energy efficiency. Combined with DeST simulation software, the building model is established, and the arc mean elasticity method is used to analyze the sensitivity of building energy load to different building envelope parameters. The results show that the external windows of the building envelope have the greatest impact on the building energy efficiency, followed by the external walls, and the roof has the least impact on the energy efficiency. The sensitivity coefficients of the annual cumulative load to the external windows, exterior walls and roofs of buildings are 7.93%, 5.76% and 5.75% respectively. Studying the influence of enclosure structure on building energy efficiency in severe cold areas has important practical value for reducing building energy consumption in severe cold areas, and provides data reference for scientifically improving building energy efficiency and building skill transformation in severe cold areas. [ABSTRACT FROM AUTHOR]

Evaporation of liquid nitrogen in another immiscible liquid occurs in many industrial applications. Existing oversimplified one-dimensional (1D) quasi-steady models, although can quantitatively predict the evaporation rate by introducing an empirical fitting parameter, rely on configurations inconsistent with experimental observation so more rigorous models are required to get in-depth physical insights and improve modeling capability. This study proposes a 2D quasi-steady-state theoretical model, free of fitting parameters, that predicts the bubble growth rate and estimates the heat transfer rate for a liquid nitrogen droplet evaporating inside a liquid pool within the spherical bubble regime. The droplet's shape and position within a spherical bubble are determined by the equilibrium between the gravitational force and the upward pressure force resulting from the vapor flow between the droplet and the pool. The vapor layer thickness is calculated to be on the order of 10 microns. Notably, the primary contribution to heat transfer arises from the lower portion of the droplet, leading to local heat flux values up to approximately six times higher at the bottom compared to the top. The predicted bubble growth is quantitatively consistent with experimental data within the capillary spherical bubble regime. Furthermore, the overall heat transfer rate Q exhibits a distinct scaling relationship with the volume ratio between the bubble and droplet, yielding Q ∼ (V b / V d) − 0.1. • Propose a fitting-parameter-free 2D model for evaporating liquid nitrogen droplet in an immiscible liquid pool. • The scaling law of droplet shrinkage rate, bubble growth rate, and heat transfer rate are presented. • The model predicted results are compared with open literature data revealing a good agreement. [ABSTRACT FROM AUTHOR]

The performance of a progressive freeze concentration process depends on solute redistribution at the ice-liquid interface during the process, which, in turn, is characterized by the parameter 'intrinsic partition coefficient'. A coupled heat and mass transfer model is proposed in this work to correlate this parameter to various characteristic velocities that are often encountered in a freeze concentration process. The robustness of the proposed model in predicting the final ice yield and the separation efficiency was validated through experimental trials conducted in a cylindrical stirred tank. Experiments investigated a model liquid solution (sucrose-water) with initial solute concentration ranging from 4% to 30%, stirring speeds varying between 100 and 500 rpm, and different cooling temperature profiles. Within the investigated characteristic velocity range (0.017–0.2), the correlation between characteristic velocity and intrinsic partition coefficient could be well approximated using a Sigmoidal function. A variation of 85% was achieved in the values of the intrinsic partition coefficient, confirming the limitations of a constant intrinsic partition coefficient, a common practice in the existing models. In addition, the proposed approach demonstrated an improvement in the prediction accuracy of the overall separation efficiency of the progressive freeze concentration process by about 40%. • Intrinsic partition coefficient varies sigmoidally with characteristic velocity. • Maximum characteristic velocity to attain pure ice is identified. • Proposed approach reduces relative error by about 40% compared to existing model. [ABSTRACT FROM AUTHOR]

The software ProCAST is used to simulate the flow field in the tundish. In the tundish without current regulator, the long nozzle injection impacts the tundish bottom directly, which is easy to cause damage to the refractory. The molten steel flow diffuses far along the bottom, and the disturbance is large near the submerged nozzle. The maximum speed at the bottom can reach 0.8m/s, and the general flow trend is that the injection flow direction is upward from the bottom to both sides, which is not conducive to the upward floating of inclusions. In the tundish with current stabilizer, the velocity of the injection decreases rapidly under the action of the liquid steel contained in the current stabilizer. Due to the attenuation of injection kinetic energy, the scouring effect on the bottom of tundish is obviously smaller and the flow field is more stable. [ABSTRACT FROM AUTHOR]

Explosion venting experiments of corn starch are carried out in a small-scale container. With the help of a high-speed camera and a pressure sensor, an interesting multiple venting behavior and its physical mechanism are comprehensively analyzed. The results suggest that the failure of the venting structure could cause three times intermittent explosion venting at most, which is negatively correlated with the opening pressure. Only the first venting significantly changes the internal explosion pressure. The flame behavior changes substantially from one venting to the other, even under the same operating conditions. The first venting flame occurs in an underexpanded jet form (with point sparks at the front), the second one is bright and spherical (without sparks), and the third one is dim and exhibits a striped pattern. In addition, the earlier the venting, the larger the average velocity of the external flame. With the opening pressure increasing, a decrease in the maximum propagation distance and time of the first venting flame is observed; simultaneously, the average flame velocity and the maximum instantaneous flame velocity increase. There is no such a phenomenon in secondary venting, although the flame brightness gradually decreases. Overall, the results may provide a theoretical basis for the safety design of explosion venting and further exploration of the explosion mechanism. [ABSTRACT FROM AUTHOR]

Gravity dams are important infrastructures, and their failure can affect public security. In this work, physical modeling was conducted to determine the dynamic responses and types of damage to gravity dams subjected to underwater explosions. Five tests under different impoundment levels, centrifugal accelerations, standoff distances, detonation depth, and equivalent weights were performed in a centrifuge. The mechanism of dynamic responses of the dam was analyzed. The peak strain and displacement by the shock wave and bubble pulse were both reached when the impulses of the dynamic loads were maximum. Different failure modes and degrees of damage were observed in the tests. When the explosive detonated in shallow water, a more substantial structural bending moment was generated by the shock wave to cause structural failure by bending. When the impoundment level was reduced, the dynamic responses were reduced due to the decrease in shock energy or impulse on the structure. However, new deformation or failure mode can be induced when the impoundment level is lower. Better understanding of the dynamic mechanism and proper control of the impoundment level would be helpful for dam protection. [ABSTRACT FROM AUTHOR]

Metal halide perovskites attract significant interest due to their remarkable performance in optoelectronic devices. However, the gap in understanding the relationship between their nanoscale structure and properties limits their application towards novel devices. In this work, twinned ferroelastic domains in single 500 nm CsPbBr3 particles are studied with 3D Bragg coherent x-ray diffraction imaging. A preferential double-domain structure is revealed in four identical particles, with one domain oriented along the [110] and the other along the [002] direction. The particles exhibit similar scattering volume ratios of 0.12 ± 0.026 between twin phases, suggesting the possibility of a deterministic formation process. The domains exhibit a difference in lattice tilt of 0.59 degrees, in excellent agreement with calculations of the lattice mismatch at the (112) twin boundary. These results provide important insights both for the fundamental understanding of ferroelastic nanoscale materials and for the performance improvement of perovskite-based devices. Moreover, this work paves the way towards real-time imaging of the domain dynamics in ferroic systems. [ABSTRACT FROM AUTHOR]

Refined layout is a basis of warehousing efficiency. Straight aisle is a typical feature of current warehouse internal layouts. The purpose of this paper is to explore the possibility of using curve aisles for warehouse layout. By Choosing typical non-traditional layouts and transforming their inclined cross-aisle trajectory into parabola, two parabolic aisle layouts, parabolic Flying-V and parabolic Fishbone, are constructed. For unit-load warehouses, based on the morphological characteristic analysis and the parabolic types selection, the picking distance model and the cross-aisle length formula are presented. Interval Numerical Simulation Method (INSM) and Genetic Algorithms (GA) are adopted to solve the model respectively in order to verify the results. This research breaks through the realistic situation of straight aisle leading warehouse layout, and enriches the relevant layout theory. The calculation results of 100 warehouses with different sizes show that the picking distance of parabolic Flying-V could be reduced by 0.22-0.62 % compared with the straight layout, and the theoretical possible improvement space has been compressed by 2.42-12.26 %. Its length of cross-aisle is shortened by -0.03-3.10 %. The picking distance of parabolic Fishbone could be only reduced by 0.02-0.04 %. The theoretical possible improvement space has been compressed by 1.27-1.83 %. But its length of cross-aisle will increase by 4.63-19.50 % significantly. We believe that the layout of non-rectangular complex special-shaped warehouses based on curve trajectory aisles would become an important research topic. In addition, after some necessary modifications to the objectives and constraints, the proposed method in this paper may also be used for the arrangement of machines and devices in a workshop in principle. [ABSTRACT FROM AUTHOR]

We systematically analyse two GRB samples with radio-loud and radio-quiet afterglows, respectively. It is interestingly found that the radio-selected GRB samples exhibit a clear dichotomy in terms of their distributions of intrinsic durations (T int), isotropic energies in γ-rays (E γ, iso), the circum-burst medium density (n), the spectral radio peak luminosity (L ν, p ) and flux densities (F host) of host galaxies. On average, the values of T int, E γ, iso, n, L ν, p , and F host of radio-quiet GRBs are relatively smaller than those of radio-loud ones. However, the redshifts and host flux densities of both samples are similarly distributed. In addition, a positive power-law correlation of |$L_{\nu ,p}\propto E_{\gamma ,\rm iso}^{0.41\pm 0.04}$| is found for the radio-loud sample, especially in accord with the supernova-associated GRBs, which is marginally consistent with that of the radio-quiet GRB sample. A negative correlation between T int and z is confirmed to similarly hold for both radio-loud and radio-quiet GRBs. The dividing line between short and long GRBs in the rest frame is at T int ≃1 s. Consequently, we propose that the radio-selected GRBs could be originated from distinct progenitors and central engines, together with environments. [ABSTRACT FROM AUTHOR]

OBJECTIVE: The global impact of COVID-19 pandemic has gained momentum rapidly. People have little information about SARS-CoV-2 (Coronavirus). Internet has become a frequently used tool to obtain information in recent years, while YouTube is one of the popular sources of information with many videos on its platform. This study aims to identify the topics regarding Coronavirus that people learned about on YouTube. The videos about Coronavirus were also evaluated in terms of the reliability of their source of information. METHODS: In total, 160 videos on Coronavirus that had 500,000 or more views were analysed. The latent Dirichlet allocation method was used in the process of identifying the topics that were then compared in terms of video parameters. The reliability of the source of information provided by videos was assessed with a modifi ed DISCERN tool. RESULTS: A proportion of 15.6 % of these videos had a scientifi c content, while 45 % of these videos were about the process entailed by the COVID-19 pandemic. In terms of video reliability, the difference between video types was found to be signifi cant; videos with scientifi c content had more reliable sources of information (p<0.001). CONCLUSION: It has been determined that the videos about the symptoms, diagnosis and treatment of COVID-19, and those with scientifi c content have the most reliable source of information on Coronavirus (Tab. 5, Fig. 1, Ref. 35). [ABSTRACT FROM AUTHOR]

Basic structural forms of reinforced concrete column-steel beam composite joints, such as beam- and column-through structures, are difficult to construct due to their complex structure. A joint connection construction method based on the ribbed angle steel was proposed in this study to improve construction performance of such joints, and the industrial assembly construction between reinforced concrete columns and steel beams was realized. By carrying out low cyclic loading test and numerical simulation of three full-scale specimens, the influence of beam--column section,the number of bolts between assembly connectors and steel beams on the performance of joints was examined by carrying out low cyclic loading test and numerical simulation of three full-scale specimens. Moreover, failure mode of joint was analyzed in detail and seismic performance indexes, such as bearing capacity, hysteretic performance, ductility, and energy dissipation capacity of joints, were compared. The results reveal that for different resistance matching among columns, beams, and connectors with ribbed angle steel, there are three failure modes of the joints, namely, shear failure in core area, slip at beam end, and slip at beam end with shear failure in core area. Seismic performance of joints varies with their failure modes. Hysteretic curve of shear failure joint in the core area shows evident pinch phenomenon. Ductility and equivalent viscous damping coefficients are 2.026 and 0.11, respectively. The seismic performance of the joint is consistent with that of the cast-in-place reinforced concrete beam--column joint. The hysteretic curve of the joint is full, ductility, and equivalent viscous damping coefficients reach 3.89 and 0.23, respectively, when slip exists between the connector and the steel beam. The joint demonstrates satisfactory seismic performance. This study provides an experimental basis for the engineering application of the novel prefabricated connection joint. [ABSTRACT FROM AUTHOR]

Gamma-ray bursts (GRBs) are the most intense explosions in the Universe. GRBs with extended emission (GRBs EE) constitute a small subclass of GRBs. GRBs EE are divided into EE-I GRBs and EE-II GRBs, according to the Amati empirical relationship rather than duration. We test here if these two types of GRB have different origins based on their luminosity function (and formation rate). Therefore, we use Lynden-Bell's c − method to investigate the luminosity function and formation rate of GRBs with EE without any assumption. We calculate the formation rate of two types of GRBs. For EE-I GRBs, the fitting function can be written as ρ(z) ∝ (1 + z)−0.34 ± 0.04 for z < 2.39 and ρ(z) ∝ (1 + z)−2.34 ± 0.24 for z > 2.39. The formation rate of EE-II can describe as ρ(z) ∝ (1 + z)−1.05 ± 1.10 for z < 0.43 and ρ(z) ∝ (1 + z)−8.44 ± 1.10 for z > 0.43. The local formation rate is |$\rho (0) = 0.03\, {\rm Gpc}^{-3} \, {\rm yr}^{-1}$| for some EE-I GRBs and |$\rho (0) = 0.32 \, {\rm Gpc}^{-3} \, {\rm yr}^{-1}$| for EE-II GRBs. Based on these results, we provide new evidence that the origins of EE-I GRBs are different from EE-II GRBs from the perspective of event rate. The EE-I GRB could be produced from the death of the massive star, but EE-II GRB may come from other processes that are unrelated to the star formation rate. Our findings indicate that the GRBs with EE could have multiple production channels. [ABSTRACT FROM AUTHOR]

Blends from the thermoplastic elastomer (TPE) of Propylene/1-butene copolymers (PPB) and Ethylene-propylene- diene monomer (EPDM) were successfully prepared by melt-mixed in an internal mixer and crosslinking through highenergy electron beam irradiation technology. The foaming process was achieved with the assistance of eco-friendly supercritical carbon dioxide (sc-CO2). The effect of EPDM content on foaming, morphology, thermal, and mechanical properties of EPDM/PPB blends with varied irradiation dose were investigated. Microstructural analysis revealed a perfect compatibility of PPB and EPDM in TPE. The increased EPDM content caused a decrease in the mechanical properties (hardness and tensile strength) of TPE; however, it has been improved with the increased irradiation dose. The thermal analysis indicated that the addition of EPDM and high-energy electron beam crosslinking resulted in a new melting peak near 150 °C in TPE, and a new crystalline phase appears during the crystallization process. Repeated processing performance tests showed that the incorporation of higher PPB content reduces the loss of mechanical properties of the prepared blend. The micro-morphology of the cell structure in foamed TPE material was investigated, and it was found that the size of cell structure gradually decreased with the increased EPDM content; however, the cell size has a tendency to increase first and then decrease with the increase of irradiation dose. At 40 kGy irradiation dose, the cell structure size is the largest among all EPDM/PPB foams. The cyclic compression test of the TPE foamed material showed that the material's resistance to repeated compression got promoted with the increased EPDM content. [ABSTRACT FROM AUTHOR]

Fast radio bursts (FRBs) are millisecond-duration radio transients and can be used as a cosmological probe. However, the dispersion measure (DM) contributed by the intergalactic medium (IGM) is hard to distinguish from other components. In this paper, we use the IllustrisTNG simulation to realistically estimate DMIGM up to z ∼ 9. We find pc cm−3 at z = 1. The probability distribution of DMIGM can be well fitted by a quasi-Gaussian function with a long tail. The tail is caused by structures along the line of sight in the IGM. Subtracting DM contributions from the Milky Way and host galaxy for localized FRBs, the DMIGM value is close to that given by the derived DMIGM–z relation. We also show the ability to constrain the cosmic reionization history with DMIGM of high-redshift FRBs in the IllustrisTNG universe. The derived DMIGM–z relation at high redshifts can be well fitted by a tanh reionization model with the reionization redshift z = 5.95, which is compatible with the reionization model used by the IllustrisTNG simulation. DMIGM of high-redshift FRBs also provides an independent way to measure the optical depth of the cosmic microwave background. Our result can be used to derive the pseudo-redshifts of nonlocalized FRBs for DMIGM < 4000 pc cm−3. [ABSTRACT FROM AUTHOR]

Sb distribution in the phases of SiO2 saturated Sb-Fe-O-SiO2-CaO system was determined for the first time through heightemperature experiment and quenching techniques, followed by Electron probe X-ray microanalysis (EPMA) in air (Ptot = 1 atm, PO2 = 0.21 atm). The phases were quantified in the temperature range of 900 °C-1200 °C and the effects of Fe/SiO2 (mass fraction) and CaO/SiO2 (mass fraction) on Sb2O3 content in the Sb-Fe-O-SiO2-CaO system were investigated at 1200 °C. The results indicated that the Sb-containing phase primarily existed in the solid solution phase at 1200 °C. With the increase of temperature from 1100 °C to 1200 °C, the Sb2O3 content in the solid solution phase increased drastically from 7.52 wt% to 17.36 wt%. Lowering the values of CaO/SiO2 and Fe/SiO2 in the smelting process effectively reduced Sb2O3 content in the slag. The verification of the experiment results suggested that the antimony content in slag was 0.57 wt%, the crude antimony yield rate was lower than 4%, and the crude antimony grade was beyond 94 wt%, which meant that the reduction of antimony content in the slag could be achieved. [ABSTRACT FROM AUTHOR]

A stationary wing placed in the wake of a bluff body experiences lift enhancement. The quasi-periodic flow in the wake causes excitation of the separated flow in the poststall conditions. The increase in the time-averaged lift force is associated with the flow separation, leading-edge vortex formation, and subsequent reattachment in a process similar to the dynamic stall of oscillating wings. The lift enhancement is maximum for an optimal offset distance from the wake centerline. At the optimal location, potential flow oscillations, rather than the direct impingement of large vortices in the wake, provide the excitation. The smaller amplitude flow oscillations lead to a large separation bubble in the time-averaged sense in the poststall regime. The delayed flow separation in the wake has a similar mechanism and frequency to those of the active flow control methods for separation. The degree of the lift enhancement is remarkable, given that the wake at a Reynolds number of 50,000 is expected to be highly three-dimensional. [ABSTRACT FROM AUTHOR]

How to simplify the nitrogen removal process, reduce the cost and improve the efficiency has become an urgent problem to be solved. In this research, the isolated HNAD (heterotrophic nitrification and aerobic denitrification) bacteria were used to remove the nitrogen in wastewater. Modified absorbent stone was used as high-efficiency and low-cost immobilized material. The modification effect was determined by the changes in mechanical strength, Zeta potential, pore structure, micrographs and biomass. The practicability of the modified carrier was further proved by experiments of environmental effect and reuse. The modified carrier had excellent performance. By comparing the degradation effects of immobilized microorganism and free microorganism, it was proved that the immobilized microorganisms have broad application prospects and strong adaptability to environmental factors. Under the optimum conditions (temperature of 30 oC, pH of 7, dissolved oxygen of 3.5 mg L-1), the removal efficiency of ammonia nitrogen reached 100% in 40 hours, the removal efficiency of total nitrogen reached 60.11% in 50 hours, and the removal rate of total nitrogen was 2.404 mg-NL-1 h-1 by immobilized microorganisms with the treatment of simulated nitrogen-containing wastewater. This research provides new material for the immobilization of HN-AD bacteria and a new way for nitrogen removal. [ABSTRACT FROM AUTHOR]

Owing to the narrow energy band of the Swift Burst Alert Telescope (BAT), several urgent issues remain unsolved. We systematically study the properties of a refined sample of 283 Swift/BAT gamma-ray bursts (GRBs) with well-measured spectral peak energy (Ep) at a high confidence level greater than 3σ. We find that the duration (T90) distribution of Swift bursts still exhibits an evident bimodality with a more reliable boundary of T90 ≃ 1.06 s instead of 2 s as found for previously contaminated samples, including bursts without well-peaked spectra, which is very close to the ∼1.27 and ∼0.8 s values suggested in the literature for the Fermi/Gamma-ray Burst Monitor and Swift/BAT catalogs, respectively. The Swift/BAT short and long bursts have comparable mean Ep values of and keV, similar to what was found for both types of BATSE bursts, which indicates that the traditional short–hard/long–soft scheme may not be tenable for certain detector energy windows. We also statistically investigate the consistency of distinct methods for Ep estimates and find that a Bayesian approach and BAND function (Band et al.) can always provide consistent evaluations. In contrast, the frequently used cutoff power-law model matches two other methods for lower Ep and overestimates the Ep by more than 70%, as Ep > 100 keV. Peak energies of X-ray flashes, X-ray-rich bursts, and classical GRBs could be an evolutionary consequence of moving from thermal-dominated to nonthermal-dominated radiation mechanisms. Finally, we find that the Ep and the observed fluence (Sγ) in the observer frame are correlated as keV, which might be a useful indicator of GRB peak energies. [ABSTRACT FROM AUTHOR]

Introduction: There has a close relationship between the balance of T helper 17 (Th17) cells and Foxp3+ regulatory T cells (Treg) and unexplained recurrent pregnancy loss (URPL). The present study is to investigate the regulatory effect of daphnetin, which is extracted from Daphne odora Var, on the balance of Th17 and Treg cells in the peripheral blood mononuclear cells (PBMCs) from patients with URPL. Material and methods: PBMCs were isolated from 35 pregnant women with URPL and 35 women with normal early pregnancies, respectively and treated with daphnetin for three days. Flow cytometry was performed to measure the proportions of Th17 and Treg cells. The level of expression of IL-6, TGF-β1 and IL-2 were detected using enzyme-linked immunosorbent assay (ELISA) and the level of expression of FoxP3, RORγt, signal transducers and activators of transcriotion 3 (STAT3) and STAT5 were detected by RT-PCR. Results: The concentrations of Th17-type cytokines IL-2 were significantly decreased in the URPL group after treatment (p < 0.01). Treg-type cytokines such as TGF-β1 and IL-6 were significantly increased after treatment (p < 0.01). At the same time, daphnetin may induce a decrease in the ratio of RORγt to Foxp3 and a Treg cell bias, which would be beneficial for pregnancy maintenance. Futhermore the expression level of STAT3 were higher in the URPL patients whereas STAT5 were lower than those in the control subjects. Conclusions: In conclusion, daphnetin may have regulatory effect on the balance of Th17 and Treg cells in the peripheral blood mononuclear cells from patients with URPL.. [ABSTRACT FROM AUTHOR]

Nonlinear energy storage and dissipation of rocks are common in earthquake, tunnel, and mining engineering. To investigate the nonlinear energy characteristics of rocks, multi-level cyclic loading–unloading triaxial compression (CLTC) tests were performed on early Cretaceous granite and Permian red sandstone. The failure modes of the granite and sandstone specimens under CLTC tests were studied. The energy parameters, such as the input, elastic, and dissipated energy densities (IE, EE, and DE, respectively), of the two types of rocks under different confining pressures were calculated, and the nonlinear interrelations among the three energy parameters were investigated. The results indicated that in the CLTC tests, the failure modes of sandstone were all shear failure. The granite specimens in the CLTC tests failed via splitting. The confining pressure had no effect on the peak strength strain energy storage index at the failure of the rock specimens, which tended to be constant. The nonlinear evolution of the DE of the granite and sandstone with respect to the EE and IE in the CLTC process was divided into three stages: an initial stage, a linear stage, and an accelerated stage. Furthermore, according to the nonlinear energy-conversion mechanism, a self-inhibition energy-conversion model was established in consideration of the confining-pressure effects. Using this nonlinear energy-conversion model, the EE and DE at any strain level can be determined. The peak strength strain energy storage index was calculated to evaluate the rockburst proneness of granite and sandstone. The results agreed well with those of the uniaxial compression test. [ABSTRACT FROM AUTHOR]

Experiments using a THz pump and an X‐ray probe at an X‐ray free‐electron laser (XFEL) facility like the Linac Coherent Light Source II (LCLS II) require frequency‐tunable (3 to 20 THz), narrow bandwidth (∼10%), carrier‐envelope‐phase‐stable THz pulses that produce high fields (>1 MV cm−1) at the repetition rate of the X‐rays and are well synchronized with them. In this paper, a two‐bunch scheme to generate THz radiation at LCLS II is studied: the first bunch produces THz radiation in an electromagnet wiggler immediately following the LCLS II undulator that produces X‐rays from the second bunch. The initial time delay between the two bunches is optimized to compensate for the path difference in THz transport. The two‐bunch beam dynamics, the THz wiggler and radiation are described, as well as the transport system bringing the THz pulses from the wiggler to the experimental hall. [ABSTRACT FROM AUTHOR]

Sequentially coupled thermo-mechanical model was used to simulate the residual stresses and residual distortions in the directed energy deposition additive manufacturing by laser. The proposed models were validated by comparison with experimental data. Different sizes of components were used to study the scaling effects. Results indicate that the residual stress can be controlled by the component sizes. This phenomenon can be explained by the bending deformation and the temperature fluctuations, especially the cooling rate, in the directed energy deposition additive manufacturing process. Both the bending deformation and the temperature fluctuations can be controlled by the ambient temperature and the designed process parameters. Analytical model was established to show how the components' sizes affect the final residual states in combination with different design parameters. [ABSTRACT FROM AUTHOR]

Uridine diphosphate glucose dehydrogenase (UGDH) is a key enzyme in the hemicellulose and pectin biosynthesis pathway and participates in the regulation of growth and development in plants. In this study, we isolated a BpUGDH gene from paper mulberry (Broussonetia kazinoki × Broussonetia papyifera) and analyzed its function and expression characteristics. The results show that the BpUGDH was expressed in all organs of paper mulberry with a higher expression in stems than in leaves and roots. A pBpUGDH::GUS gene construct was highly expressed in transgenic Arabidopsis thaliana seedlings, and its expression was induced by a low temperature, methyl jasmonate, gibberellin A3, ethylene, and auxin. The overexpression of BpUGDH increased the soluble sugar content, promoted the accumulation of hemicellulose, and enhanced the vegetative growth of transgenic plants. These results provide a basis for regulating the growth and adaptability of paper mulberry and improving its utilization value via genetic modification of the BpUGDH gene. [ABSTRACT FROM AUTHOR]

• New analytical transient linear flow is rigorously modeled in heterogeneous fractured liquid-rich tight reservoirs with non-static properties. • Improved rate-transient analysis workflow is proposed to estimate reservoir/fracture properties. • Three liquid-rich shale field examples in North America are analyzed to demonstrate the practical applicability of new model. The industry is increasingly reliant on rate-transient analysis (RTA) to extract valuable information about the reservoir and hydraulic fractures. However, the application of current, commercially-available RTA models can lead to incorrect estimates of reservoir/fracture properties, potentially causing costly mistakes to be made in capital planning and reserve estimation. The root cause of these errors is that currently-available analytical solutions used in RTA models largely ignore reservoir heterogeneities, and assume static reservoir properties. In this work, a new transient linear flow is rigorously modeled in unconventional reservoirs with (1) pressure-dependent rock and fluid properties and (2) both continuous and discontinuous (heterogeneous) porosity and permeability. To achieve this, new transformations of pseudo-pressure, pseudo-time and pseudo-distance are first introduced to reduce the temporal and spatial non-linear diffusivity equation to that with approximately constant coefficients. Both a Laplace-domain solution and approximate analytical solution to the diffusivity equation are verified against a series of fine-grid numerical simulations for the assumption of fractal-based reservoir heterogeneity (over a wide range of stress-dependent rock and fluid properties). The results indicate that reservoir heterogeneity can result in nonlinear square-root-of-time plots. Further, rock and fluid pressure-dependencies act to decrease the slope of the square-root-of-time plot and affect reservoir/fracture property evaluations. Three liquid-rich shale (LRS) field examples in North America are analyzed to demonstrate the practical applicability of the new RTA models. Additional value of new RTA models over the sophisticated numerical simulation is to provide us an improved backforward-analysis workflow that can be used to quantify both effective fracture half-length and non-uniform permeability distribution around the fractures. The major contribution of this work is the introduction of a new analytical model for evaluating the transient linear flow period for the cases of arbitrary reservoir heterogeneity and non-static reservoir properties. This new approach is particularly useful for evaluating the effectiveness of hydraulic fracturing operations by extracting the spatial variability of reservoir quality within the stimulated reservoir volume (SRV). [ABSTRACT FROM AUTHOR]

This paper innovatively introduces particle swarm optimization (PSO) and neural network (NN) to solve the job-shop scheduling problem (JSP). Each particle in the swarm was treated as a connection in the NN. Then, the connection weight was iteratively updated according to the latest position of the corresponding particle. In this way, the NN no longer falls into the local optimum trap. Then, the PSO-optimized NN was applied to solve the JSP with a single objective: minimizing the maximum makespan. Through experiments on benchmark problems, it is confirmed that the proposed strategy outperforms the other scheduling methods in fulfilling the optimization objective. (Received, processed and accepted by the Chinese Representative Office.) [ABSTRACT FROM AUTHOR]

Developing eco-friendly, flexible thermoplastic elastomeric foams based on poly(styrene-(ethylene-co-butylene)- styrene) (SEBS) is a challenging task because of its poor melt strength. A promising approach to overcome this challenge is the use of synergistic technologies, such as combination of irradiation, supercritical fluid foaming, and steam-chest molding technologies. Herein, foamed beads were produced from pre-crosslinked SEBS beads using supercritical nitrogen as blowing agent, followed by subsequently efficient steam-chest molding to obtain midsole part. The crosslinking was accomplished under the assistance of electron beam. The rheology properties and foaming behavior reveals that the viscosity and modulus of the matrix increase with the increase of crosslinking resulting from increasing the irradiation dose (ID). With increasing the ID, successful foaming with larger expansion and improved cell morphology was achieved. SEBS bead foams were successfully obtained from 65 kGy-derived pre-crosslinked beads through steam-chest molding which showed a specific gravity of 0.252 g·cm-3 and comparable/superior mechanical properties to/than that of commercial thermoplastic polyurethane (TPU) or ethylene-vinyl acetate copolymer (EVA) foams. Especially, the higher elasticity and resilience of SEBS foams meet well the desirable properties for footwear application which supports SEBS to be an alternative for TPU or EVA. [ABSTRACT FROM AUTHOR]

A pot study was conducted to elucidate morphological and physiological responses of Spatholobus suberectus Dunn accessions to four nitrogen application rates (0, 10, 20, and 30 mmol L-1) and two watering regimes (daily irrigation and irrigation every 10 d for a month). The results showed that water deficit led to marked decreases in leaf water relations and photosynthetic parameters regardless of the N treatments. Under drought conditions, the reductions in net photosynthesis occurred mainly due to stomatal factors. Although the leaf N content and stem mass ratio were positively correlated with N application, other morphological and physiological characteristics were negatively correlated or nonsignificantly correlated with N application under limited water supply. As the root nodules of S. suberectus can provide sufficient N supply, and high N applications made S. suberectus plants more vulnerable to drought stress, we suggest that no N supplement is required for S. suberectus seedlings. [ABSTRACT FROM AUTHOR]

Different methods are developed for simulation of microstructural evolution in metals and alloys subject to Laser Additive Manufacturing. The Monte Carlo (MC) method is combined with a new proposed two scales strategy for simulation of the solidification and the subsequent solid-state phase transformation in Ti–6Al–4V.The Cellular Automaton (CA) method shows its higher efficiency in comparison with MC method. Moore neighbor type with energy barrier is recommended for the CA simulation of grain growth of Al 6061. The phase field (PF) model shows that different temperature gradients lead to different columnar grains in different layers of Ti–32wt.%Nb. The computed structures are related to experimental observations. [ABSTRACT FROM AUTHOR]

Friction stir additive manufacturing is studied experimentally and numerically. Different to conventional friction stir welding, re-stirring and re-heating can be found for friction stir additive manufacturing. The new generated phenomena are investigated by new integrated model, which is established based on Monte Carlo method and precipitate evolution model with combination of finite element model. Corresponding experiments are performed. Results indicate that different grain morphology and size, different hardness, and different yield strength can be found in different layers. The re-stirring and re-heating to the formed layers can lead to enhancement of mechanical properties with smaller grains and with higher hardness and yield strength. In comparison with first layer, the hardness and yield strength on second layer are increased due to the decrease of the peak temperature. After 2–3 layers, the mechanical properties of formed layers are not further affected by the new added layers. [ABSTRACT FROM AUTHOR]

There have been extensive researchs on cycles in regular graphs, partic- ularly 3-connected cubic graphs. Generalized Petersen graphs, denoted by GP(n,k), are highly symmetric 3-connected cubic graphs, which have attracted great atten- tion. The Hamiltonicity of GP(n,k) has been studied for a long time and thoroughly settled. Inspired by Bondy's meta-conjecture that almost every nontrivial condition for Hamiltonicity also implies pancyclicity, we seek for more cycle structures in this class of graphs, by figuring out the possible lengths of cycles in them. It turns out that generalized Petersen graphs, though not generally pancyclic, miss only very few possible length of cycles. For k 2 f2,3g, we completely determine all possible cycle lengths in GP(n,k). We also obtain some results for GP(n,k) where k is odd. In particular, when k is odd, and n is even and suficiently large, GP(n,k) is bipartite and weakly even pancyclic. [ABSTRACT FROM AUTHOR]

Abstract A new heat source model is proposed for the simulation of the temperature rises in the laser deposition melting additive manufacturing process. The obtained temperature histories in different layers can be used to predict the microstructural evolutions in a multiscale strategy including the grain cluster scale and single grain scale in Monte Carlo model. It is found that re-melting and re-heating due to different temperature histories of different layers are main factors to affect the microstructural evolutions in LAM. By use of the predicted microstructural and the self-consistent model, the flow stresses at different strain rates and temperatures are predicted. The predicted flow stress shows that the flow stress is higher in the middle of the as-built LAM product but lower near the top or the bottom surfaces. The increase of the scanning speed of laser can lead to the increase of the size of heat affected zone, which is the reason for the formation of larger grain sizes and more α generations in higher scanning speed. Higher α volume fraction is the main reason for higher mechanical property in higher scanning speed. [ABSTRACT FROM AUTHOR]

Seasonal water storage fluctuations are critical for evaluating water scarcity linked to climate forcing and human intervention. Here we compare seasonal changes in land total water storage anomalies using seven global hydrologic and land surface models (WGHM, PCR‐GLOBWB, and five GLDAS models) to GRACE satellite data in 183 river basins globally. This work builds on previous analysis that focused on total water storage anomaly trends. Results show that most models underestimate seasonal water storage amplitudes in tropical and (semi)arid basins and land surface models generally overestimate amplitudes in northern basins. Some models (CLM‐5.0 and PCR‐GLOBWB) agree better with GRACE than others. Causes of model‐GRACE discrepancies are attributed to missing storage compartments (e.g., surface water and/or groundwater) and underestimation of modeled storage capacities in tropical basins and to variations in modeled fluxes in northern basins. This study underscores the importance of considering water storage, in addition to water fluxes, to improve global models. Plain Language Summary: We are relying more and more on global models to understand the water cycle, but we need to assess the reliability of model output. In this study we compare seasonal amplitudes in land total water storage from global models with those from GRACE satellite data in river basins globally. We found that seasonal amplitudes in total water storage account for more than half of the total signal, except in semiarid basins. Seasonal amplitudes are highest in tropical basins and lowest in semiarid basins. Some models agree better with GRACE than others (CLM‐5.0 and PCR‐GLOBWB). Most models underestimate GRACE‐derived seasonal amplitudes in tropical and semiarid basins but overestimate seasonal amplitudes in northern high latitude basins. The main cause of the discrepancies in tropical basins is likely insufficient storage capacity and lack of surface water inundation to accommodate the large seasonal storage variations. In northern high latitude basins, differences in snow physics and evapotranspiration increase seasonal amplitudes in water storage in newer versions of land surface models, overestimating GRACE‐derived seasonal amplitudes and reducing agreement with GRACE relative to earlier versions. Reliable models of seasonal variations in water storage are critical for assessing water scarcity, estimating response to climate extremes, and managing water resources. Key Points: Modeled seasonal amplitudes are underestimated in tropical and semiarid basins and overestimated in northern basins relative to GRACEModel‐GRACE discrepancies are attributed to insufficient storage capacities in tropical basins and biases in fluxes in northern basinsThis study highlights the value of using water storage, in addition to traditional water flux, in assessing and improving global models [ABSTRACT FROM AUTHOR]

The migration behavior of Bi atoms in Cu/Sn-58Bi/Cu solder interconnects undergoing liquid-solid electromigration (L-S EM) was in situ observed using synchrotron radiation real-time imaging technology. Bi atoms tend to migrate from the cathode toward the anode resulting in the linear growth of Bi-rich phase layer at the anode in both the heating and cooling stages but not in the dwelling stage. Since the temperature of Sn-Bi solder in the dwelling stage is higher than those in both the heating and cooling stages, the electrically driven migration effect diminishes with increasing temperature. As a result, a three-layer equilibrium distribution of Bi-rich, Sn-Bi and Sn-rich phases across the solder is observed in the dwelling stage of 140 °C, and a uniform Bi distribution across the solder is observed in the dwelling stage of a higher temperature of 170 °C, i.e., Bi atoms fully diffuse backward at such a high temperature. The abnormal migration behavior of Bi atoms is determined by the combined effect of chemical potential gradient-induced flux (Jchem) and EM-induced flux (Jem). The EM-induced flux (Jem) is determined by the effective charge number (Z*) of Bi atoms that is calculated as − 3.57 at 140 °C based on the growth kinetics of the Bi-rich layer. Furthermore, the Z* value of Bi atoms is calculated as − 3.04 by using a modified model for calculating Z* of liquid metals, which agrees well with the experimental value. The present work provides a reference for purifying refractory metals from alloys. [ABSTRACT FROM AUTHOR]