bluuebunny/crossref_metadata_2025 huggingface dataset:
Research on main defects and prevention measures of metal material welding based on ultrasonic nondestructive testing technology
Authors: Ren Xiaoguang
Published: August 2022

In the welding process of metal materials, defects often occur due to various factors, which not only affect the welding quality, but also adversely affect the properties of materials. In order to control these defects, it is necessary to take corresponding measures according to the actual situation in the welding process. With the development of society, ultrasonic nondestructive testing technology is widely used in industrial field. It can detect the internal damage of the tested object with simple operation and good performance. Ultrasonic nondestructive testing technology is used to detect hidden defects in welding of metal materials, which can effectively ensure the service performance of metal materials. In this paper, the main defects and preventive measures of metal welding based on ultrasonic nondestructive testing technology are discussed.
Mesoscale simulation on the shock response of functionally graded Al-PTFE material
Authors: Tang Le , Hu Die , He Suo , Ge Chao , Jiang Zengrong
Published: August 2022

In this paper, the shock response of functionally graded Al-PTFE granular composites is firstly investigated by means of mesoscale simulations. A tailored arrangement of granular filler is infiltrated with matrix to study the effects of density gradient on mechanical and chemical characteristics of the material under impact loading. Based on the shock wave propagations, noticeable differences among pressure, temperature, and strain response are visualized at the grain-level. Results demonstrate that higher pressure is concentrated in the shock wave front and decrease over time. Moreover, a much greater energy-releasing and higher strain deformation exhibit along the grain/matrix interfaces. Compared with uniform reactive material, the functionally graded reactive material with decreased density gradient has a higher initial velocity in wave propagation, and the sample with increased density gradient has superior capability in wave attenuation, and a higher level of hot-spots concentration.
Effects of defects on magnetic properties of molybdenum doped indium oxide
Authors: Ma Jianping , Chen Jingjing , Huang Erchuan
Published: August 2022

Based on density functional theory, this paper systematically calculated the effects of different Mo doping concentrations and neutral intrinsic defects on the electronic structure and magnetic properties of Mo-doped In2O3 (IMO) systems. Studies have shown that the magnetic properties of the IMO system are mainly derived from the hybridization of doped Mo atoms and neighboring O atoms, and as the Mo doping concentration increase, the total magnetic moment of the IMO system also increases, and the magnetic properties increase. In the same configuration, VO, Oi, VIn, and Ini were introduced, and the magnetization energies were 107.29 meV, 2.21 meV, 0.24 meV and-703.72 meV, respectively. Except for the system containing Ini, it transformed into an antiferromagnetic ground state, Others still exhibit ferromagnetic coupling, which shows that different intrinsic defects have a regulatory effect on doping magnetism.
Mathematical analysis of Van der Pauw’s method for measuring resistivity
Authors: Geng Yihui
Published: August 2022

The Van der Pauw method has tremendous significance in measuring material resistivity in arbitrary shapes. The extended Van der Pauw method can be used to measure the resistivity of anisotropic materials or even materials with holes without enormous measurements or calculations. However, the method requires that the material be thin enough to be considered quasi-two-dimension, and the measurement of equivalent resistance is largely influenced by contact resistance. This paper aims to find the factors that influence the measurement’s accuracy by formula analyzing, trying to improve the precision of Van der Pauw’s measurement.
Study on bonding strength and layer structure design of TiAlSiN multilayer gradient coating
Authors: Wu Yan , Guo Zhiyuan , Li Zhaoyang , Wang Bing , Chen Qiang , Zhang Ergeng
Published: August 2022

Compared with TiN coating and TiAlN coating, the TiAlSiN superhard coating has more outstanding comprehensive properties. However, the TiAlSiN superhard coating has different physical properties from the substrate, which causes large internal stress at the interface, and reduces the bonding strength of the coating and the substrate. In this paper, according to the design criteria of nano-micron multilayer structure coating, a multilayer gradient TiAlSiN coating is designed to improve the bonding strength of TiAlSiN superhard coating, and studying the bonding strength and mechanical properties after high temperature oxidation of TiAlSiN multilayer gradient coatings prepared by cathodic arc ion plating. The results show that the designed multilayer gradient structure TiAlSiN coating has four layers: TiN layer, TiAlN layer, TiAlSiN layer and TiSiN layer. The bonding strength of the TiAlSiN multilayer gradient coating conforms to the industrial grade HF1 and it maintains good bonding properties and mechanical properties in a high temperature environment below 1000°C. It is expected to provide reference for the study and design of improving the bonding strength of the coating.
Rheological and mechanical properties of automobile polypropylene/silica (PP/SiO2) nanocomposites
Authors: Sui Yang , Cui Yi , Cong Chuanbo , Meng Xiaoyu , Zhou Qiong
Published: August 2022

The research of automotive materials is mainly focused on the lightweight and low pollution. Polypropylene (PP) has become the hot spot of automobile materials due to its low cost, low density, and low pollution. However, it is necessary to modify PP due to the poor toughness, high shrinkage and poor weather resistance. The requirements for automotive PP are high toughness, high strength, high impact resistance and high melt flowability. In this paper, PP/SiO2 nanocomposites were prepared by a mixing machine and a twin-screw extruder. The effects of SiO2 particles contents on the rheological and mechanical properties of the nanocomposites were investigated. The results show that SiO2 spheres play a lubricating role in the matrix, which improves the processability of PP without sacrificing its mechanical properties.
Research Progress in Intrinsic Self-healing Polyurethane Materials Based on Dynamic Reversible Non-covalent Bonds
Authors: Ke Ruoyi , Lin Zhaowen , Zhang Hongbo , Zhou Shilin
Published: August 2022

Polyurethane (PU) is a polymer with great capabilities like high elasticity, low-temperature resistance, wear resistance, and corrosion resistance. However, it will inevitably be damaged in processing or long-term use, which will shorten the service life of the material and increase the potential safety hazards. The widespread use of polyurethanes has given researchers more motivation to make polyurethanes self-healing, thereby eliminating material damage and potential safety hazards to a certain extent. This paper mainly reviews the self-healing mechanism and the research progress of intrinsic self-healing polyurethanes based on dynamic reversible non-covalent bonds, including H-bonding, metal-ligand, π-π and host-guest interactions. This paper holds that the non-covalent self-healing polyurethane can repair cracks repeatedly without adding a repair agent by introducing the above non-covalent reversible bonds into the polyurethane with good mechanical properties. Various types of reversible bonds provide a variety of options for self-healing. In addition, through the research on the preparation, mechanical properties, and self-healing ability of various self-healing polyurethanes, this paper summarizes and analyzes the prospect and existing problems of self-healing polyurethanes. In the future, researchers should focus on solving the existing deficiencies. This paper looks forward to finding a better scheme to improve the performance of self-healing polyurethanes and preparing ideal self-healing polyurethane materials that appear in the public’s field of vision. This paper is written to provide help for the research of self-healing PU and accelerate the transformation of the world to green development.
Self-toughening of epoxy resin by introduction of highly crosslinked thermoset epoxy microspheres
Authors: Wu Xiao , Hung Xinzuo , Zhang Shuwei , Yang Maowei , Su Tao
Published: August 2022

The theories and technologies concerning polyolefin toughening with rubber or inorganic rigid particle have been studied comprehensively, the results indicated that the toughening with rubber always lowers the modulus and heat resistance of materials. Also, toughening with inorganic rigid particle is not good because of its low dispersion and miscibility with epoxy resin. Monodisperse epoxy microspheres (EMs) with high crosslinking density were prepared with Polypropylene glycol with molecular weight of 600 as the reaction solvent and trifunctional epoxy resin (TDE-85) and aromatic diamine (DETDA) as the precursors. The formation of EMs was investigated in detail. The crosslinked microspheres were used as toughening agent to realize DGEBA/DDS system self- toughening. When adding 5wt% epoxy microspheres, the impact strength improved by 87% and Tg increased more than 6 °C. The results show that the prepared epoxy microspheres with high crosslinking density can not only greatly improve the toughness of epoxy resin, but also improve its heat resistance.
Microstructural evolution during recovery of deformed aluminium—Effect of deformation strain
Authors: Yu Tianbo
Published: August 2022

Recovery takes place during annealing of a deformed metal, releasing some of the stored energy. Many recovery mechanisms have been proposed in the literature and these mechanisms strongly depend on the deformation microstructure. In this work, recent progress in the study of recovery in aluminium is reviewed. In lightly deformed aluminium, subgrain growth (through boundary migration and coalescence) is found to be an important recovery mechanism, whereas in heavily deformed samples, uniform coarsening through Y-junction motion is found to be the dominant recovery mechanism. The kinetics of recovery follows a universal coarsening model for aluminium deformed to both low and high strains, in which the apparent activation energy increases in the course of recovery. Furthermore, a new definition of recovery is suggested to be compatible with observations at both low and high strains.
Microstructure and chemical characterization of Linear Friction Welded aerospace materials with focus on dissimilar joints
Authors: Boyat X , Ballat-Durand D , Marteau J , Bouvier S , Risbet M , Favergeon J
Published: August 2022

This study is focused on a through characterization of the microstructure and chemical composition of dissimilar linear friction welded joints. First, Ti-6Al-2Sn-4Cr-2Mo (Ti6242) and Ti-5Al-2Sn-2Zr-4Mo-4Cr (Ti17) joints are described to identify the mechanisms behind the successful cohesion of the material surfaces. It was found that continuous dynamic recrystallization and cohesion took place through grain-boundary migration in a shared single phase β-domain obtained through high temperature and high strain conditions. Then, the possibility of assembling Ti6242 and Inconel 718 is examined. Chemical results combined with microstructure and crystal orientation analyses showed that the intermixing zone formed between the materials was particularly heterogeneous, with the development of an intermediate bimodal microstructure, mainly composed of Ti-β phase and Ti2Ni intermetallic phase.
Solid solution hardening effects on structure evolution and mechanical properties of nanostructured binary and high entropy alloys after high pressure torsion
Authors: Keil T , Minnert C , Bruder E , Durst K
Published: August 2022

Two different alloy series (Cu-X, Ni-X) have been selected to investigate the effects of solutes on the saturation grain size, the thermal stability and mechanical properties after high pressure torsion. The results of the Cu-X series indicate that the saturation grain size does not correlate with the stacking fault energy but shows good agreement with solid solution hardening according to the Labusch model. This correlation does not only hold for binaries, but also for chemically complex high entropy alloys (Ni-X) in the form of (CrMnFeCo)xNi1-x, where the Varvenne model is used to describe solid solution hardening. The alloy series exhibit a grain size in the range of 50 – 425 nm after high pressure torsion and the solutes increase the strength as well as the thermal stability of the alloys after annealing. The nanostructured alloys exhibit an enhanced strain rate sensitivity exponent, as determined from nanoindentation strain rate jump and constant contact pressure creep testing, whereas an enhanced rate sensitivity is found at low strain rates. The relatively lower rate sensitivity of the alloys as well as their higher thermal stability indicate, that defect storage and annihilation is strongly influenced by a complex interaction of solutes, dislocations and grain boundaries.
Analysis of inter- and intragranular variations based on 3DXRD data and crystal plasticity
Authors: Juul N Y , Oddershede J , Beaudoin A , Winther G
Published: August 2022

The synchrotron-based technique of 3DXRD/HEDM has proven a powerful tool to investigate individual grains in the bulk of a polycrystal during plastic deformation. Comparisons between such experimental data and crystal plasticity simulations typically show agreement with respect to overall qualitative trends. However, comparisons at the level of individual grains are in general less successful. Experimental observations and crystal plasticity simulations for a number of representative grains are analysed for similarities and differences in order to elucidate the origin of these. The comparison points at insufficient modelling of grain interactions, hardening and possibly also in the handling of ambiguities. Spatially resolved experimental data on the orientation spread is expected to provide the information needed to improve the predictive capacity at the level of individual grains.
Recrystallization kinetics of cold rolled Gum Metal
Authors: Lindkvist A , Holm Johansen T , Kørup Pedersen L , Zhang Y , Juul Jensen D
Published: August 2022

A wire of a β-Titanium alloy known as Gum Metal was cold rolled to a reduction of 80% and heat treated for times in the range 3-120 minutes at a fixed temperature of 740 °C to yield a set of partially recrystallized microstructures. The recrystallization course was evaluated by light optical microscopy and Electron Backscatter Diffraction, based on which the recrystallization kinetics was analysed using the Johnson-Mehl-Avrami-Kolmogorov (JMAK) model. This analysis showed that the kinetics of this material does not follow the traditional JMAK behaviour but has two distinct stages with very different Avrami exponents.
Influence of shielding gas flow on the uniformity of additively manufactured martensitic stainless steel
Authors: Pan Z , Nadimpalli V K , Christiansen T L , Andersen S A , Kjer M B , Mishin O V , Zhang Y
Published: August 2022

Shielding gas flow is essential to the additive manufacturing (AM) process, and the effects of argon shielding gas flow variation on the macroscopic homogeneity of additive manufactured stainless steel parts have been studied using an open-architecture AM system. Such a variation manifests itself layer-by-layer within one part and part-by-part across the build plate. Within one build, a combination of balling behavior, conduction melting and keyhole melting is observed across the build plate using the same laser parameters. Quantitative characterization of the melt pool shapes show that the melt pool width and the penetration depth exhibit the largest variations. Possible relations between the gas flow condition and macroscopic structure variations are discussed and guidelines for improved design of a gas flow system as well as future research directions are suggested for achieving macroscopically uniform metal AM.
3D characterization of a nanostructured Al-Cu-Mg alloy
Authors: Zhu Wanquan , Yang Ran , Feng Zongqiang , Wu Guilin , Godfrey Andrew , Huang Xiaoxu
Published: August 2022

Three-dimensional (3D) characterization of variations in crystallography and chemistry of nanostructured metals will provide vital information to understand their mechanical and thermal behaviours. This study applied a surface sliding friction treatment (SSFT) at liquid nitrogen temperature to produce nanostructured surface layers in a peak-aged Al-Cu-Mg alloy. The nanostructured surface was characterized by means of 3D orientation mapping in the transmission electron microscope (3D-OMiTEM) and atom probe tomography (APT). 3D-OMiTEM results revealed a lamellar structure with an average lamellar boundary spacing of 26 nm at the topmost surface layer (depth < 20 μm), which is much finer than normally achievable in commercial purity Al deformed to high strain levels. Based on the 3D-OMiTEM data, a five-parameter grain boundary character analysis was carried out. It was found that low angle grain boundaries dominate the nanoscale structure and that the grain boundary plane distribution of high angle lamellar grain boundaries shows a preference around {101}. APT analysis showed segregation of Cu and Mg atoms at lamellar boundaries, which is believed to play a role in stabilizing the boundaries and enhancing the structural refinement during SSFT.
Effect of inclusion type on the rotating bending fatigue properties of a high carbon chromium bearing steel
Authors: Shi Zhiyue , Cao Wenquan , Shang Chengjia , Zhang Xiaodan
Published: August 2022

The use of the double vacuum melting route (conventional second refining + vacuum arc refining, CSR+VAR) and the electroslag remelting route (vacuum induction melting + electroslag remelting, VIM+ESR)) has been investigated for the SAE52100 (100Cr6) bearing steel. The tensile properties, impact toughness, hardness and RCF life of the CSR+VAR steel and the steel prepared using the VIM+ESR route are similar. The number and size of TiN inclusions in the VIM+ESR steel are higher and larger than those in the CSR+VAR steel, providing an explanation for the observation of better fatigue properties for the CSR+VAR steel. Two major types of inclusions, magnesium aluminates/Al2O3-CaO-CaS and TiN, are located in different areas in a map of stress intensity factor versus rotatory bending fatigue cycles (NRBF
). The negative impact of TiN inclusions on fatigue properties are greater than those of magnesium aluminates/Al2O3-CaO-CaS inclusions.
In-situ study of microstructural evolution and strain distribution during single axis tension of 316L stainless steel prepared by selective laser melting
Authors: Wang W Y , Gao W Q , Sun S , Godfrey A
Published: August 2022

A combined digital image correlation (DIC) and electron backscatter diffraction (EBSD) study of the multi-scale strain distribution and microstructure evolution during tensile loading has been carried on 316L stainless steel samples prepared by selective laser melting (SLM). The initial material shows a range of microstructural heterogeneity. Macro- and micro-DIC results reveal a non-uniform distribution of plastic strain over several length scales, including the formation of localized slip-bands at the intra-grain level. No obvious correlation is found between the heterogeneity in plastic strain and either grain size, grain morphology or the orientation of the cellular structures formed during SLM. Intragranular orientation subdivision and the evolution of local misorientation have also been investigated by EBSD during tension, where a complex pattern of heterogeneity in both microstructure and plastic strain is found.
Microplasticity in inhomogeneous alloys
Authors: Pachaury Yash , Kumagai Tomohisa , El-Azab Anter
Published: August 2022

We report on a preliminary modelling effort to understand the influence of compositional inhomogeneity on alloy microplasticity from a dislocation dynamics perspective. We tackle this problem by multiscale simulations in three steps: (1) analysis of the 3D composition morphology in alloys with tendency to undergo spinodal instability both thermally and under irradiation, with bcc FeCrAl alloys as a model system, (2) atomistic simulation of the dislocation mobility as a function of the local alloy composition, and (3) using dislocation dynamics simulations to understand the impact of composition inhomogeneity on microplasticity. The dislocation dynamics model takes into consideration the coherency stress associated with composition inhomogeneity when computing the forces driving the dislocation motion and on cross slip. Our preliminary investigation shows that the stress-strain response of the alloy and the dislocation density evolution depend on the wavelength of the composition fluctuations. Our investigation also shows that the alloy inhomogeneity may alter the cross-slip activity, which, in turn, influences the dislocation density evolution. The dependence of the dislocation mobility and coherency stress on local composition and its variation, as well as the altered cross slip rates, cause the dislocation microstructure to differ relative to that in the homogeneous alloy of the same average composition.
Multiscale Exploration of Texture and Microstructure Development in Recrystallization Annealing of Heavily Deformed Ferritic Alloys
Authors: Yildirim C , Mavrikakis N , Cook P K , Rodriguez Lamas R , Poulsen H F , Detlefs C , Kutsal M
Published: August 2022

We present a multi-scale study of recrystallization annealing of an 85% cold rolled Fe-3%Si-0.1%Sn alloy using a combination of dark field X-ray microscopy (DFXM), synchrotron X-ray diffraction (SXRD), and electron backscatter diffraction (EBSD). Grains of interest from high stored energy (HSE) regions in a 200μm-thick sample are studied using DFXM during isothermal annealing. The intra-granular structure of the as deformed grain reveals deformation bands separated by ≈ 3–5° misorientation. Geometrically Necessary Dislocation evolution during recrystallization and growth is investigated. These findings are supported by a quantitative non-destructive texture analysis using SXRD in terms of pole figures and orientation distribution functions. Although no significant macroscopic texture change is observed up to 50% recrystallization, the calculated texture index indicates different nucleation and growth processes at various stages of annealing. Our results show that zones of local misorientation in the HSE regions are decisive for the formation and growth of recrystallized grains.
Recent advances of lab-based diffraction contrast tomography – reconstruction speed benchmark testing and validations
Authors: Sun J , Bachmann F , Oddershede J , Lauridsen E
Published: August 2022

Lab-based diffraction contrast tomography (DCT) enables the user to reconstruct 3D grain maps of polycrystalline materials non-destructively. For each grain, the morphology and crystallographic orientation, as well as derived properties such as grain boundaries, can be determined. Through two application examples this paper demonstrates the data acquisition and reconstruction speed of the current implementation and validates the resulting grain maps. Firstly, for a conventional Laue focusing scan of an AlCu sample comprising 340 grains, major performance enhancements of the reconstruction algorithm have reduced the reconstruction time from half a day to half an hour. The second example highlights an advanced scan with projection geometry of an oriented electrical steel sheet containing 7,800 grains. While the data collection time is around a day for each of the data sets, the boosted reconstruction of the advanced acquisition data takes half a day and gives the full grain map without the need for stitching. After the major algorithm speed enhancements, grain map qualities are comparable with misorientations below 0.02° and grain boundary distances less than a voxel for both samples.
A simple procedure to produce bio-mimic brick-and-mortar microstructure in commercially pure Ti
Authors: Liu Chengze , Xu Jianping , Li Huan , Zhang Yusheng
Published: August 2022

The extremely high fracture toughness of nacre is known to arise from its brick-and-mortar microstructure and has inspired the development of metals, metallic glasses and composites with similar bio-mimic microstructures. Although various approaches have been proposed to produce materials with a brick-and-mortar microstructure, including powder metallurgy, electro deposition, spray deposition, etc., the production of large-scale samples remains to be a challenge. In this research, we present a simple way to produce large samples of commercially pure Ti with a brick-and-mortar microstructure, which includes a pre-heat-treatment followed by deformation in the single-phase temperature region and subsequent annealing. EBSD characterization shows a layered microstructure in the produced samples resembling a brick-and-mortar structure.
Texture in cold rolled and high-temperature annealed Cu foils
Authors: Guo J , Li X , Wu G L , Zhang R Q , Huang T L , Shi H F , Zhang C L , Jensen D , Huang X
Published: August 2022

Thick single crystal Cu foil substrates with specific crystallographic orientations such as {111} and {110} planes parallel to the rolling plane are desired for epitaxial growth of two-dimensional materials such as graphene. In this study, annealing experiments of a 46 μm thick cold-rolled foil were carried out at temperatures in the range of 300-1040 °C. The texture evolution during annealing was followed by electron backscatter diffraction (EBSD) orientation mapping. It was found that the texture evolution may be divided into three stages: at relatively low annealing temperatures, a strong cube texture develops with a small population of grains having relatively larger deviations from the cube orientation; at medium temperatures, these grains with large deviations grow abnormally; and at the highest temperature, annealing twins form in the abnormally growing grains giving rise to new orientations including some with the {111} planes parallel to the rolling plane.
Effect of Aging Treatment on the Microstructure and Mechanical Properties of Fe-Mn-Al-C Low Density Steel
Authors: Li G Y , Kong L , Liu E Z , Zhang X D , Cao W Q , Wang Y H
Published: August 2022

Fe-Mn-Al-C steel has excellent weight reduction potential. In this study, the microstructure and mechanical properties of Fe-25Mn-11Al-1.0C steel after solution treatment at 1050 °C and aging at 450~650 °C are studied. The results show that with the increase of aging temperature, the strength increases first and then decreases. The plasticity and strength show a trade-off relationship. With the increase of the aging temperature, the plasticity first decreases and then increases. The above-mentioned changes in mechanical properties are closely related to the changes in the morphology and distribution of κ-carbides during the aging process. In general, the precipitation of κ-carbides is beneficial to obtain higher strength, but has a detrimental effect on plasticity.
Microstructure and mechanical properties of a 0.1C5Mn3Al steel fabricated by warm drawing
Authors: Zhang L , Cai P , Cheng X , Zhang L , Hou Z , Huang X
Published: August 2022

In the present study, a recently developed low density 0.1C5Mn3Al dual phase steel was subjected to warm drawing at 600 °C. Microstructure observations and mechanical properties were investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and tensile tests. It was found that carbide precipitates together with laminated ferrite were formed before and after warm drawing. After warm drawing by a Von Mises strain of 1.96, the yield stress (YS) improved from 650 MPa to 1100 MPa and the uniform elongation (UE) dropped to 2%. Further heat treatments were performed to tune the microstructures and mechanical properties. Discontinuous yielding phenomenon was widely observed in the heat treated samples and 15% hot rolling was used to eliminate this discontinuous yielding.
Recrystallization kinetics of the AA5xxx series aluminum alloys - revisited
Authors: Vandermeer Roy , Lin Fengxiang , Lei Xiuchuan , Sanders Robert Edward , Jensen Dorte Juul
Published: August 2022

In previous work [1], we analyzed the recrystallization kinetics in cold-rolled AA5657 and AA5182 based on measurements of the volume fraction of recrystallized material, the free (unimpinged) surface area density and the average size of the recrystallizing grains, plus the contiguity between recrystallizing grains, for a series of partially recrystallized samples. In that work, the calculated growth and nucleation rates were used as basis from the analysis. These two properties are derived from the measured parameters, which, as shown in the present work, adds to their uncertainty. In the present paper, we revisit the kinetics using improved stereological data and perform a full microstructural path analysis. The new analysis results are compared to the previous ones and the implications of using the different types of data sets and analytical approach for the interpretation of the kinetics are discussed.
The Effect of Compositional Heterogeneity on the Martensite Start Temperature of a High Strength Steel During Rapid Austenitisation and Cooling
Authors: Taylor M , Fellowes J W , Hill P O , Rawson M J , Burnett T L , Pickering E J
Published: August 2022

Many low alloy steels are compositionally heterogeneous due to the preferential segregation of alloying elements to the dendritic or interdendritic regions when the steel is first solidified (microsegregation). This segregation is often ignored when using CCT diagrams to predict the phase transformation behaviour of steels, but may be of importance in some industrially-relevant cases. This work focuses on the martensite start temperature (Ms
) of Super CMV, a high strength aerospace steel, after rapid austenitisation treatment to various peak temperatures from 900 °C to 1300 °C. It was found that the average Ms
temperature increased with increasing peak temperature (and prior austenite grain size) at peak temperatures of 1100°C and above, which is to be expected conventionally. However, at peak temperatures of below 1100°C, the Ms
temperature increased with decreasing prior-austenite grain size. It is proposed that this was due to the presence of non-dissolved carbides in these conditions, particularly in enriched bands of material, which deplete the matrix and hence raise Ms
.
Dislocation sub-structures, recovery and recrystallization in pure tantalum
Authors: Moussa C , Baton J , Geslin W
Published: August 2022

Plastic deformation, static recovery and recrystallization in pure tantalum are analyzed in the present paper. Quantitative analysis of dislocation sub-structures were done. Sub-structures development is completely dependent on crystallographic orientation. No clear effect of recovery was observed when direct analysis was made. Hence, recovery was studied through its effect on recrystallization. Recovery heat treatments followed by a recrystallization heat treatment were applied to compare the recrystallized state of samples which were subject to prior recovery with those which were not. Results show that recrystallization is accelerated in the early stages of recovery (low temperature or low annealing time or low plastic strain). On the opposite, in the advanced stages of recovery, it slows down recrystallization. Results show again an influence of crystallographic orientation. Static recrystallization was also investigated and the influence of crystallographic orientation, most probably inherited from the deformed state through dislocation sub-structures, was observed. Based on experimental results, a discussion on the mechanisms of nucleation in the different orientation grains is presented. Finally, a discussion is made on the quantification of stored energy. The effect of the observation scale and the choices of considering dislocation density or dislocation sub-boundaries energies from EBSD data is discussed.
Stored energy calculation in AA 1050 based on deformation microstructure from electron backscatter diffraction data
Authors: Yan Yingrui , Pan Hongjiang , Godfrey Andy , Jensen Dorte Juul , Zhang Xiaodan
Published: August 2022

An AA1050 aluminum plate was cold rolled to a true strain of 1.9, and the stored energy was calculated based on microstructural parameters, namely the dislocation boundary spacing and the misorientation distribution, determined from large area electron back-scatter diffraction maps with an indexed fraction higher than 90% before any data cleaning operations. Three methods were used to determine the dislocation boundary spacing and the misorientation distribution. The results show significant differences in the dislocation boundary spacings and the misorientation distributions obtained by the different methods, especially for boundaries with misorientation angles below 2°. These deviations lead to significant differences in the calculated stored energy. A discussion of the three approaches to determine stored energies is presented.
Cooperative enhancement of strength and ductility in metallic materials: The role of local stress/strain evolution on the plastic flow behavior
Authors: Miao K S , Xia Y P , Li D Y , Wu H , Fan G H
Published: August 2022

Simultaneous enhancement of strength and ductility is one of the eternal topics for the community of metallic materials. The heterostructure architecture, e. g. layered structure, is one of the potential methods to evade the strength-ductility trade-off dilemma in recent years. However, there is still a lack of a deeper understanding to excellent strength-ductility combinations. In the present study, we focused on the local stress, which drives local plastic deformation. The local represents the affected scale of the stress. The evolution processes of local stress/strain upon loading of typical model materials of Ti/Ti, Ti/Al, and Al/Al layered metals (LMs) were quantitatively characterized by in situ electron microscope, synchrotron X-ray diffraction, and neutron diffraction. We found that the deformation characteristics were closely associated with the local stress/strain evolution process, and highlighted the key role of local stress/strain in revealing the deformation mechanisms. This work therefore may open a new route to design new metallic materials through the tailoring of local stress/strain evolution.
Isogenous hyperelliptic and non-hyperelliptic Jacobians with maximal complex multiplication
Authors: Dina Bogdan , Ionica Sorina , Sijsling Jeroen
Published: August 2022

We analyze complex multiplication for Jacobians of curves of genus 3, as well as the resulting Shimura class groups and their subgroups corresponding to Galois conjugation over the reflex field. We combine our results with numerical methods to find CM fields

K
K

for which there exist both hyperelliptic and non-hyperelliptic curves whose Jacobian has complex multiplication by

Z

K

\mathbb {Z}_K

. More precisely, we find all sextic CM fields

K
K

in the LMFDB for which (heuristically) Jacobians of both types with CM by

Z

K

\mathbb {Z}_K

exist. There turn out to be 14 such fields among the 547,156 sextic CM fields that the LMFDB contains. We determine invariants of the corresponding curves, and in the simplest case we also give an explicit defining equation.
A generalization of the Hopf degree theorem
Authors: Kvalheim Matthew
Published: August 2022

The Hopf theorem states that homotopy classes of continuous maps from a closed connected oriented smooth

n
n

-manifold

M
M

to the

n
n

-sphere are classified by their degree. Such a map is equivalent to a section of the trivial

n
n

-sphere bundle over

M
M

. A generalization of the Hopf theorem is obtained for sections of nontrivial oriented

n
n

-sphere bundles over

M
M

.
Impacts of plant and soil stoichiometry on species diversity in a desert ecosystem
Authors: Ji Suwan , Jiang Lamei , Hu Dong , Lv Guanghui
Published: August 2022

Plant and soil stoichiometric ratios can be used to explain changes in the structural and functional characteristics of plant communities. Exploring the relationships between the stoichiometric ratios and plant diversity is helpful to further elucidate the effects of soil and nutrient constraints on community vegetation. However, such studies remain poorly understood in desert ecosystems. In this study, we analysed the effects of soil moisture and salt content on soil and leaf stoichiometry, species diversity and their relationships in the desert ecosystem of the Ebinur Lake basin. The results showed that: (i) Compared with the low soil moisture and salinity (SW2) environment, the soil and leaf C, N, P contents and soil stoichiometric ratios were larger in the high soil moisture and salinity (SW1) environment, and the leaf stoichiometric ratios were smaller. (ii) In SW1 environment, species diversity was negatively correlated with soil C:N and C:P, but weakly correlated with soil stoichiometric ratios in SW2 environment. In addition, the relationships between it and leaf stoichiometric ratios were reversed in different moisture and salinity environments. (iii) Structural equation modelling showed that leaf C:P, C:N and soil C:P had strong effects on species diversity. This research aims to provide a scientific reference for maintaining plant diversity, vegetation reconstruction and ecosystem restoration in desert areas, and enrich the ecological stoichiometric theory of desert ecosystems.
Six identical tRNATrpCCA genes express a similar amount of mature tRNATrpCCA but unequally contribute to yeast cell growth
Authors: Hayashi Sachiko , Matsui Masaya , Ikeda Ayano , Yoshihisa Tohru
Published: August 2022

Saccharomyces cerevisiae has 6 synonymous tRNATrpCCA genes encoding the identical sequence, including their intronic region. They are supposed to express tRNATrpCCA in the same quality and quantity. Here, we generated single to quintuple deletion strains with all the possible combinations of the synonymous tRNATrpCCA genes to analyze whether those individual genes equally contribute cell viability and tRNA production. The quintuple deletion strains that only harbor tW(CCA)J, tW(CCA)M, or tW(CCA)P were viable but almost lethal while the other quintuple deletions showed moderately impaired growth. These growth differences were not obvious among the quadruple deletion strains, which expressed almost one third of mature tRNATrpCCA in the wild type. Therefore, no dosage compensation operates for tRNATrpCCA amount, and growth variations among the quintuple deletion strains may not simply reflect differences in tRNATrpCCA shortage. Yeast may retain the redundancy of tRNATrpCCA genes for a noncanonical function(s) beyond the supply of the tRNA to translation.
Accelerating the discovery of anticancer peptides targeting lung and breast cancers with the Wasserstein autoencoder model and PSO algorithm
Authors: Yang Lijuan , Yang Guanghui , Bing Zhitong , Tian Yuan , Huang Liang , Niu Yuzhen , Yang Lei
Published: August 2022

In the development of targeted drugs, anticancer peptides (ACPs) have attracted great attention because of their high selectivity, low toxicity and minimal non-specificity. In this work, we report a framework of ACPs generation, which combines Wasserstein autoencoder (WAE) generative model and Particle Swarm Optimization (PSO) forward search algorithm guided by attribute predictive model to generate ACPs with desired properties. It is well known that generative models based on Variational AutoEncoder (VAE) and Generative Adversarial Networks (GAN) are difficult to be used for de novo design due to the problems of posterior collapse and difficult convergence of training. Our WAE-based generative model trains more successfully (lower perplexity and reconstruction loss) than both VAE and GAN-based generative models, and the semantic connections in the latent space of WAE accelerate the process of forward controlled generation of PSO, while VAE fails to capture this feature. Finally, we validated our pipeline on breast cancer targets (HIF-1) and lung cancer targets (VEGR, ErbB2), respectively. By peptide-protein docking, we found candidate compounds with the same binding sites as the peptides carried in the crystal structure but with higher binding affinity and novel structures, which may be potent antagonists that interfere with these target-mediated signaling.
MGEGFP: a multi-view graph embedding method for gene function prediction based on adaptive estimation with GCN
Authors: Li Wei , Zhang Han , Li Minghe , Han Mingjing , Yin Yanbin
Published: August 2022

In recent years, a number of computational approaches have been proposed to effectively integrate multiple heterogeneous biological networks, and have shown impressive performance for inferring gene function. However, the previous methods do not fully represent the critical neighborhood relationship between genes during the feature learning process. Furthermore, it is difficult to accurately estimate the contributions of different views for multi-view integration. In this paper, we propose MGEGFP, a multi-view graph embedding method based on adaptive estimation with Graph Convolutional Network (GCN), to learn high-quality gene representations among multiple interaction networks for function prediction. First, we design a dual-channel GCN encoder to disentangle the view-specific information and the consensus pattern across diverse networks. By the aid of disentangled representations, we develop a multi-gate module to adaptively estimate the contributions of different views during each reconstruction process and make full use of the multiplexity advantages, where a diversity preservation constraint is designed to prevent the over-fitting problem. To validate the effectiveness of our model, we conduct experiments on networks from the STRING database for both yeast and human datasets, and compare the performance with seven state-of-the-art methods in five evaluation metrics. Moreover, the ablation study manifests the important contribution of the designed dual-channel encoder, multi-gate module and the diversity preservation constraint in MGEGFP. The experimental results confirm the superiority of our proposed method and suggest that MGEGFP can be a useful tool for gene function prediction.
Stromal cells of the endometrium and decidua: in search of a name and an identity
Authors: Ruiz-Magaña Maria Jose , Llorca Tatiana , Martinez-Aguilar Rocio , Abadia-Molina Ana Clara , Ruiz-Ruiz Carmen , Olivares Enrique G
Published: August 2022

Human endometrial and decidual stromal cells are the same cells in different environments (nonpregnancy and pregnancy, respectively). Although some authors consider decidual stromal cells to arise solely from the differentiation of endometrial stromal cells, this is a debatable issue given that decidualization processes do not end with the formation of the decidua, as shown by the presence of stromal cells from both the endometrium and decidua in both undifferentiated (nondecidualized) and decidualized states. Furthermore, recent functional and transcriptomic results have shown that there are differences in the decidualization process of endometrial and decidual stromal cells, with the latter having a greater decidualization capacity than the former. These differences suggest that in the terminology and study of their characteristics, endometrial and decidual stromal cells should be clearly distinguished, as should their undifferentiated or decidualized status. There is, however, considerable confusion in the designation and identification of uterine stromal cells. This confusion may impede a judicious understanding of the functional processes in normal and pathological situations. In this article, we analyze the different terms used in the literature for different types of uterine stromal cells, and propose that a combination of differentiation status (undifferentiated, decidualized) and localization (endometrium, decidua) criteria should be used to arrive at a set of accurate, unambiguous terms. The cell identity of uterine stromal cells is also a debatable issue: phenotypic, functional, and transcriptomic studies in recent decades have related these cells to different established cells. We discuss the relevance of these associations in normal and pathological situations.
How to Regulate Carbon Emissions with Climate-Conscious Consumers
Authors: Herweg Fabian , Schmidt Klaus M
Published: August 2022

Carbon prices are the most cost-effective instrument to reduce CO$_2$ emissions, but there is strong political opposition to raising them to the efficient level. Therefore, additional efforts of consumers, firms and local governments are required. We study how different regulatory regimes affect moral behaviour and show that a carbon tax complements voluntary efforts to reduce emissions, while cap and trade discourages them. The opportunity to invest in offsets increases welfare, while the option to buy and delete emission rights induces more emissions and reduces welfare. Furthermore, cap and trade shifts the burden of adjustment to poor consumers and has dysfunctional incentive effects.
Experimental quantity, mental budgeting and food choice: a discrete choice experiment application
Authors: Lin Wen , Ortega David L , Caputo Vincenzina
Published: August 2022

Food discrete choice experiments typically define product alternatives with a researcher-predetermined and sometimes arbitrary quantity. Results reveal that the use of a researcher-prespecified experimental quantity leads to biased welfare estimates. Differences in marginal utility of money are found with a resulting upward bias in willingness to pay estimates when small pre-defined product quantities are used. Higher-income consumers show more evident bias. This evidence cautions the use of a researcher-predetermined quantity to design alternatives in choice tasks and also proposes an alternative experimental design that accounts for these effects by matching the quantity in experiments to consumer’s actual purchase quantity.
Digging deeper into the taxonomy of Cylindrospermum and description of Johanseniella tripurensis gen. et sp. nov. from India
Authors: Pal Sagarika , Saraf Aniket , Kumar Naresh , Singh Arush , Talukdar Utkarsh , Kohar Niraj , Singh Prashant
Published: August 2022

The wet soil-inhabiting cyanobacterium URH-6-PS was collected from the state of Tripura, India, and characterized using a polyphasic approach. Initial microscopic analysis indicated the strain to be a member of the genus Cylindrospermum, however, the 16S rRNA gene phylogenetic analysis showed some interesting results. The strain URH-6-PS clustered in the Clade I, which positioned itself outside the Cylindrospermum sensu stricto clade with strong probability/bootstrap support, indicating that the strain may not belong to the genus Cylindrospermum. Further, analysis of the 16S–23S ITS region using the folded secondary structures of the D1-D1′, Box-B, and V3 helices and the 16S–23S ITS percentage dissimilarity values clearly indicated the distinctiveness of strain URH-6-PS from other members of the Clade I. The detailed investigations conducted in this study provided sufficient evidence that the taxonomic status of the members of Clade I need to be revised. Interestingly, all members of the clade I originated from tropical and subtropical habitats while members of the Cylindrospermum sensu stricto clade have been reported from temperate conditions. Previous studies had also indicated the possibility of the formation of tropical and subtropical Cylindrospermum-like genera, and thus this comes across as a much-awaited study to resolve the taxonomic complexities around the genus Cylindrospermum. Based on the results obtained in this study and the trends observed in the earlier studies, we describe a novel Cylindrospermum-like genus Johanseniella gen. nov., with the type species Johanseniellatripurensis sp. nov. in accordance with the International Code of Nomenclature for algae, fungi, and plants.