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We present a novel formalism to characterize elastic heterogeneities in amorphous solids. In particular, we derive high-order strain-energy expansions for pairwise energies under athermal quasistatic dynamics. We then use the presented formalism to study the statistical properties of pairwise expansion coefficients and their link with the statistics of soft, quasilocalized modes, for a wide range of formation histories in both two- and three-dimensional systems. We further exploit the presented framework to access local yield stress maps by performing a non-linear stress–strain expansion within a cavity embedded in a frozen matrix. We show that our "bond micromechanics" compare well with the original "frozen matrix" method, with the caveat of overestimating large stress activations. We additionally show how local yield rules can be used as an input for a scalar elasto-plastic model (EPM) to predict the stress response of materials ranging from ductile to brittle. Finally, we highlight some of the limits of simple mesoscale models in capturing the aging dynamics of post-yielding systems. Intriguingly, we observe subdiffusive and diffusive shear band growths for particle-based simulations and EPMs, respectively. [ABSTRACT FROM AUTHOR]

The ice surface is known for presenting a very small kinetic friction coefficient, but the origin of this property remains highly controversial to date. In this work, we revisit recent computer simulations of ice sliding on atomically smooth substrates, using newly calculated bulk viscosities for the TIP4P/ice water model. The results show that spontaneously formed premelting films in static conditions exhibit an effective viscosity that is about twice the bulk viscosity. However, upon approaching sliding speeds in the order of m/s, the shear rate becomes very large, and the viscosities decrease by several orders of magnitude. This shows that premelting films can act as an efficient lubrication layer despite their small thickness and illustrates an interesting interplay between confinement enhanced viscosities and shear thinning. Our results suggest that the strongly thinned viscosities that operate under the high speed skating regime could largely reduce the amount of frictional heating. [ABSTRACT FROM AUTHOR]

Absolute measurements of solid-material compressibility by magnetically driven shockless dynamic compression experiments to multi-megabar pressures have the potential to greatly improve the accuracy and precision of pressure calibration standards for use in diamond anvil cell experiments. To this end, we apply characteristics-based inverse Lagrangian analysis (ILA) to 11 sets of ramp-compression data on pure platinum (Pt) metal and then reduce the resulting weighted-mean stress–strain curve to the principal isentrope and room-temperature isotherm using simple models for yield stress and Grüneisen parameter. We introduce several improvements to methods for ILA and quasi-isentrope reduction, the latter including calculation of corrections in wave speed instead of stress and pressure to render results largely independent of initial yield stress while enforcing thermodynamic consistency near zero pressure. More importantly, we quantify in detail the propagation of experimental uncertainty through ILA and model uncertainty through quasi-isentrope reduction, considering all potential sources of error except the electrode and window material models used in ILA. Compared to previous approaches, we find larger uncertainty in longitudinal stress. Monte Carlo analysis demonstrates that uncertainty in the yield-stress model constitutes by far the largest contribution to uncertainty in quasi-isentrope reduction corrections. We present a new room-temperature isotherm for Pt up to 444 GPa, with 1-sigma uncertainty at that pressure of just under ± 1.2 % ; the latter is about a factor of three smaller than uncertainty previously reported for multi-megabar ramp-compression experiments on Pt. The result is well represented by a Vinet-form compression curve with (isothermal) bulk modulus K 0 = 270.3 ± 3.8 GPa, pressure derivative K 0 ′ = 5.66 ± 0.10 , and correlation coefficient R K 0 , K 0 ′ = − 0.843. [ABSTRACT FROM AUTHOR]

The demand for applications, such as coatings, separation filters, and electronic packaging, has greatly driven the research of polymer films. At nanometer scale, mechanical properties of thin polymer films can significantly deviate from bulk. Despite outstanding progresses, there still lack deep discussions on nonlinear viscoelastic–viscoplastic response and their interactions under nanoconfinement. In this work, by conducting measurements via the bubble inflation method and modelling using Schapery and Perzyna equations, we demonstrate nonlinear viscoelastic–viscoplastic properties of freely standing thin polystyrene (PS) films. The results show the unchanged glassy compliance and the rubbery stiffening phenomenon for thin PS films, where the lower rubbery plateau in rubbery stiffening may originate from the induced molecular orientation by plastic deformation. With decreasing film thickness, viscosity and yield stress in viscoplasticity increase in an exponential and a linear trend, respectively, indicating the significant role of nanoconfinement effect on viscoplastic properties. These findings may reveal that there are many properties from linear viscoelasticity to nonlinear viscoelasticity–viscoplasticity that need to be explored and unveiled for sufficient understanding of the nanoconfinement effect on altering mechanical behavior of polymers. [ABSTRACT FROM AUTHOR]

We present a method for computing locally varying nonlinear mechanical properties in particle simulations of amorphous solids. Plastic rearrangements outside a probed region are suppressed by introducing an external field that directly penalizes large nonaffine displacements. With increasing strength of the field, plastic deformation can be localized. We characterize the distribution of local plastic yield stresses (residual local stresses to instability) with our approach and assess the correlation of their spatial maps with plastic activity in a model two-dimensional amorphous solid. Our approach reduces artifacts inherent in a previous method known as the "frozen matrix" approach that enforces fully affine deformation and improves the prediction of plastic rearrangements from structural information. [ABSTRACT FROM AUTHOR]

Flooding stress declines oxygen availability in roots that induce hypoxia stress in plants, thereby severely decline plant growth. Study was undertaken to clarify how potassium supplementation alleviates flooding stress in cotton plants. We applied potassium (K) fertilizer in pot soils at different levels; K0 = Control (No K), K1 = 30 mg kg−1, K2 = 60 mg kg−1 and K3 = 80 mg kg−1 with different duration of flooding stress s. D0 = Normal irrigation (0 day flooding), D1 = three days flooding, D2 = six days flooding, D3 = nine days flooding, D4 = twelve days flooding. The K supplementation (80 mg kg−1) in soil with 3-day flooding stress showed better combination for mitigating flooding stress. The supplementation of K3 dose (80 mg kg−1) alleviated flooding against 3-day initial flooding (D1) of which physiological traits showed better response compared to prolonged flooding stress (12-day flooding stress). The result suggests that K-involving flooding stress mitigation strategy in cotton plants was active for initial flooding stress (3-day flooding stress), while it was not fully active for pronged (upto 12-day flooding stress). Furthermore, we found K significantly improved antioxidant enzymes, photosynthetic performance, yield attributes, and lint quality. [ABSTRACT FROM AUTHOR]

Physical aging refers to relaxation of the polymer glassy state toward the amorphous state and this phenomenon affects their physical‐mechanical properties. This work investigates the effect of physical aging on polymer scratch behavior and visibility. It was shown that mechanical properties were significantly modified over the aging time, especially the yield stress, in turn affecting polymer scratch behavior. As a matter of fact, the critical load for the onset of scratch visibility was shown to increase with the aging, thus improving sensitivity of polymer to scratches. Such behavior was strictly related to the yield stress increase with the aging time. The usefulness of the present work is highlighted, and some future perspectives are discussed. [ABSTRACT FROM AUTHOR]

With the extensive use of manufactured sand and admixtures, it has been observed that as the shear rate increases, the shear rate–shear stress curve of some fresh wet shotcrete materials increasingly deviates from a linear correlation. It is necessary to study the rheological properties of wet shotcrete using a nonlinear model due to the large error when utilizing the Bingham model to describe the concrete. The torque-velocity curve of wet shotcrete was determined using an ICAR rheometer in this study. The experimental data was fitted using the Bingham model, Herschel-Bulkley (H-B) model, and modified Bingham (M-B) model, resulting in the determination of the associated rheological parameters. The M-B model exhibits the most optimal fitting effect, followed by the H-B model and the Bingham model. As the shear rate reaches a specific value, the M-B model consistently represents a higher degree of divergence from linearity compared to the H-B model. Furthermore, considering the limitations of the H-B model which includes varying dimension parameters, this study enhanced the calculation approach for determining the equivalent plastic viscosity based on Larrard et al.'s (Mat Struct 31:494–498, 1998) research. Ultimately, the impact of the mix parameters on the yield stress and plastic viscosity of the three rheological models was analyzed through the range approach. This study is beneficial for enhancing the comprehension of the rheological characteristics of wet shotcrete. [ABSTRACT FROM AUTHOR]

Molecular dynamics simulations are performed to investigate the mechanical behavior of nanotwinned NiCo-based alloys containing coherent L12 nano-precipitates at different temperatures, as well as the interactions between the dislocations and nano-precipitates within the nanotwins. The simulation results demonstrate that both the yield stress and flow stress in the nanotwinned NiCo-based alloys with nano-precipitates decrease as the temperature rises, because the higher temperatures lead to the generation of more defects during yielding and lower dislocation density during plastic deformation. Moreover, the coherent L12 phase exhibits excellent thermal stability, which enables the hinderance of dislocation motion at elevated temperatures via the wrapping and cutting mechanisms of dislocations. The synergistic effect of nanotwins and nano-precipitates results in more significant strengthening behavior in the nanotwinned NiCo-based alloys under high temperatures. In addition, the high-temperature mechanical behavior of nanotwinned NiCo-based alloys with nano-precipitates is sensitive to the size and volume fraction of the microstructures. These findings could be helpful for the design of nanotwins and nano-precipitates to improve the high-temperature mechanical properties of NiCo-based alloys. [ABSTRACT FROM AUTHOR]

It is well recognised that the rheology of an interstitial fluid has profound effects on debris flow dynamics. Existing design guidelines for multiple resisting barriers, however, do not consider the rheological behaviour of debris flows explicitly while estimating barrier spacing. A modified overflow equation is proposed, considering an improved overflow trajectory and a new yield stress-based velocity attenuation model, to estimate the overflow distance in two-phase flows. This study experimentally investigates the effects of yield stress of an interstitial fluid on the impact behaviour of two-phase flows with similar Froude numbers against dual-rigid barriers. The flow composition is varied to model a wide range of natural flows based on dimensionless yield stress. The results reveal that the hydrodynamic impact coefficient increases with increasing dimensionless yield stress and exceeds the existing international design guidelines by more than 13%. The existing guidelines underestimate the overflow distance by up to 115%. The modified formulation is verified and conservatively predicts overflow distance for water floods to debris flows. It is recommended that the dimensionless yield stress of interstitial fluid together with Froude number should be used to characterise the impact and overflow dynamics of two-phase flow for a conservative design of dual barriers. [ABSTRACT FROM AUTHOR]

In this work, the rheological properties of four multi-wall carbon nanotubes (MWCNTs)/polyethylene (PE) composites containing 1 wt.% (mPEC1), 3 wt.% (mPEC3), 5 wt.% (mPEC5), and 10 wt.% (mPEC10) MWCNTs prepared by the masterbatch method were investigated and compared with those of the pure PE. The rheological investigation includes strain sweeping, frequency sweeping, stress relaxation behavior, yield stress, characteristic relaxation time, temperature effect on linear viscoelastic behavior, and gel behavior. It is mainly found that (1) the MWCNTs-MWCNTs interaction resulting in MWCNTs network structure in the PE matrix and the MWCNTs-PE interfacial interaction increase the storage and loss moduli of the MWCNTs/PE composite in comparison with those of pure PE; (2) the time-temperature equivalence principle is applicable only for pure PE and mPEC1; (3) for gel behavior of MWCNTs/PE composite at 160–180 °C, the φ g value decreases with the increase of temperature and the highest S g value is obtained at 170 °C. [ABSTRACT FROM AUTHOR]

This paper presents an overview of recent works on microscale mechanical and other properties of silicon nitride (Si 3 N 4) determined by microcantilever bending tests and their relationships with the processing and microstructures. We first focus on deformation behaviors and fracture strength of Si 3 N 4 single crystals. β-Si 3 N 4 single crystals are plastically deformed at room temperature under high bending stress, and the yield stress depends on the crystal orientation. The critical resolved share stress of the primary slip system is determined to be below 1.5 GPa from the yield stress. Next, we address microscale mechanical properties of Si 3 N 4 polycrystalline ceramics. Emphasis is placed on their grain-boundary strength or toughness in conjunction with intergranular glassy film (IGF) which is determined by processing parameters such as sintering additives. Assessment is made on two cases of fractures at the IGF-grain interface and that within the IGF, and in each of the cases, effects of rare earth oxide additives are discussed. In Si 3 N 4 ceramics doped with Al 2 O 3 , β-SiAlON layer forming on β-Si 3 N 4 grains enhances the microscale grain-boundary strength. Finally, we shed light on microscale property-degradation behaviors of Si 3 N 4 ceramics, including the deterioration due to the contact with molten Al and the corrosion in sulfuric acid solution. The variation of the microscale properties appears in very short periods compared to the macroscale approaches, demonstrating the advantage in terms of rapid assessment of time-dependent degradation behaviors. [ABSTRACT FROM AUTHOR]

The present paper deals with self‐heating phenomenon under cyclic loading at high loading frequency 20 kHz and low stress amplitude (i.e., far below the yield stress). The main goal is to propose two different methods to determine the heat source field at the origin of this temperature change. To do that the local expression of the 1D heat diffusion equation and experimental thermal data fields obtained by an infrared camera are used. The proposed methodology is applied to experimental results from tests performed on a ML340 maraging steel. [ABSTRACT FROM AUTHOR]

We employ the theory of asymptotic homogenization (AH) to study the elasto‐plastic behavior of a composite medium comprising two solid phases, separated by a sharp interface and characterized by mechanical properties, such as elastic coefficients and “initial yield stresses” (i.e., a threshold stress above which remodeling is triggered), that may differ up to several orders of magnitude. We speak of “plastic” behavior because we have in mind a material behavior that, to a certain extent, resembles plasticity, although, for biological systems, it embraces a much wider class of inelastic phenomena. In particular, we are interested in studying the influence of gradient effects in the remodeling variable on the homogenized mechanical properties of the composite. The jump of the mechanical properties from one phase to the other makes the composite highly heterogeneous and calls for the determination of effective properties, that is, properties that are associated with a homogenized “version” of the original composite, and that are obtained through a suitable averaging procedure. The determination of the effective properties results convenient, in particular, when it comes to the multiscale description of inelastic processes, such as remodeling in soft or hard tissues, like bones. To accomplish this task with the aid of AH, we assume that the length scale over which the heterogeneities manifest themselves is several orders of magnitude smaller than the characteristic length scale of the composite as a whole. We identify both a fine‐scale problem and a coarse‐scale problem, each of which characterizes the elasto‐plastic dynamics of the composite at the corresponding scale, and we discuss how they are reciprocally coupled through a transfer of information from one scale to the other. In particular, we highlight how the coarse‐scale plastic distortions influence the fine‐scale problem. Moreover, in the limit of negligible hysteresis effects, we individuate two viscoplastic effective coefficients that encode the information of the two‐scale nature of the composite medium in the upscaled equations. Finally, to deal with a case study tractable semi‐analytically, we consider a multilayered composite material with an initial yield stress that is constant in each phase. Such investigation is meant to contribute to the constitution of a robust framework for devising the effective properties of hierarchical biological media. [ABSTRACT FROM AUTHOR]

The introduction of foreign atoms significantly alters the grain boundary (GB) behavior in materials, consequently affecting their mechanical properties. However, the effects of random doping and GB segregation of foreign atoms on deformation mechanisms and mechanical properties remain unknown. In this work, the GB behavior and deformation mechanisms of Ta bicrystals under various element doping and segregation conditions were investigated using molecular dynamics simulation. The results reveal that the deformation mechanism of pure Ta bicrystals involves dislocation slip and twinning initiated from GBs. Notably, both GB doping and segregation induce BCC to FCC phase transformations, which is attributed to the non-uniform displacement of atoms in the {112} plane along the 〈111〉 direction. Doping with W and Mo elevates the yield stress, whereas doping with Nb exhibits an inverse effect. Remarkably, the segregation of W, Mo, and Nb significantly enhances mechanical properties, surpassing the effects of GB doping. This segregation modifies the GB composition, reduces GB energy, and enhances GB stability. Our study sheds light on the pivotal role of GB doping and segregation in improving the mechanical properties and understanding the deformation mechanisms of nanocrystalline materials, offering vital insights for future material design and engineering. [ABSTRACT FROM AUTHOR]

Cold stress is a critical factor affecting rice production worldwide. The application of cold-resistant agents may improve the cold resistance and yield of crops. To screen for suitable cold-resistant agents for machine-transplanted early rice, the effects of uniconazole, abscisic acid, and zinc-amino acids chelate and their spraying times (seed soaking stage, one leaf and one heart stage, two leaves and one heart stage, 7 days before the transplanting stage, and regreening stage) on the yield and cold resistance of machine-transplanted early rice were investigated. Moreover, the application method (spraying amount: 750 and 1125 g ha-1; spraying time: 7 days before the transplanting stage, transplanting stage, regreening stage, and transplanting stage and regreening stage) for the most suitable cold-resistant agent was optimized. The zinc-amino acids chelate was better than the other two cold-resistant agents for promoting rice tillering and increasing the leaf area index, dry matter weight, antioxidant enzyme activities (CAT, SOD, POD) and yield (i.e., 9.22% and 7.14% higher than uniconazole and abscisic acid, respectively), especially when it was applied in the regreening stage. The examination of spraying amounts and times indicated that the zinc-amino acids chelate dosage had no significant effect on the yield and cold resistance of early rice. However, the rice yield and antioxidant enzyme activities were highest when samples were sprayed once in the transplanting stage and the regreening stage. On the basis of the study results, 750 g ha-1 zincamino acids chelate applications in the transplanting and regreening stages of machine-transplanted early rice plants may be ideal for increasing cold stress resistance and yield. [ABSTRACT FROM AUTHOR]

The utilization of geopolymer as a grouting material has gained significant attention in research and construction applications. Geopolymer grout is a type of binding material that differs from traditional grouts, typically based on Portland cement. Researchers have explored its effectiveness and potential applications in grouting processes, considering its unique properties and characteristics. In this paper, various studies employing and utilizing geopolymer as a grouting material are reviewed. The emphasis is on mixture design of geopolymer grout, physical property, chemical composition of geopolymer grout, rheological behavior of geopolymer grout such as yield stress (in case of Bingham fluid) and viscosity, and engineering properties such as compressive strength, expansion, shrinkage, etc. [ABSTRACT FROM AUTHOR]

SUMMARY Leaf senescence is a complex developmental process influenced by abscisic acid (ABA) and reactive oxygen species (ROS), both of which increase during senescence. Understanding the regulatory mechanisms of leaf senescence can provide insights into enhancing crop yield and stress tolerance. In this study, we aimed to elucidate the role and mechanisms of rice (Oryza sativa) LONG GRAIN 3 (OsLG3), an APETALA2/ETHYLENE RESPONSIVE FACTOR (AP2/ERF) transcription factor, in orchestrating dark‐induced leaf senescence. The transcript levels of OsLG3 gradually increased during dark‐induced and natural senescence. Transgenic plants overexpressing OsLG3 exhibited delayed senescence, whereas CRISPR/Cas9‐mediated oslg3 mutants exhibited accelerated leaf senescence. OsLG3 overexpression suppressed senescence‐induced ABA signaling by downregulating OsABF4 (an ABA‐signaling‐related gene) and reduced ROS accumulation by enhancing catalase activity through upregulation of OsCATC. In vivo and in vitro binding assays demonstrated that OsLG3 downregulated OsABF4 and upregulated OsCATC by binding directly to their promoter regions. These results demonstrate the critical role of OsLG3 in fine‐tuning leaf senescence progression by suppressing ABA‐mediated signaling while simultaneously activating ROS‐scavenging mechanisms. These findings suggest that OsLG3 could be targeted to enhance crop resilience and longevity. [ABSTRACT FROM AUTHOR]

To investigate the mechanism of polypropylene fiber (PPF) on the rheological and thixotropic properties of cemented paste backfill containing mineral admixtures, the concept of water film thickness (WFT) was introduced. The packing density of the tailings-binder-PPF (TBP) system was measured in dry and wet conditions and the WFT was calculated accordingly. Additionally, the rheological parameters (yield stress, thixotropy, etc.) of the fiber-reinforced cemented paste backfill (FRCPB) were quantified. The results demonstrate that the wet packing test is a more appropriate method for measuring the packing density of the TBP system. The PPF length has a slight adverse effect on the packing density, and the packing density initially increases and then decreases with the PPF content. The reasons can be attributed to the filling effect and wedge effect of the fibers, respectively. In addition to the packing density, the thixotropy of FRCPB is also affected by the interaction of fibers. WFT is a crucial factor affecting the yield stress of FRCPB, with which it exhibits a strong linear relationship. The study identified that the optimum PPF content for enhancing the rheological and thixotropic properties of CPB is 0.2%, with a fiber length of 9 mm, balancing flowability and stability for practical application in mining backfill operations. These insights can guide the optimization of CPB mixtures, enhancing their flowability and stability during placement in mined-out spaces. By improving the fill quality and reducing the risk of blockage during backfill operations, the results offer practical benefits in increasing the safety and efficiency of underground mining activities. [ABSTRACT FROM AUTHOR]

Food texture is one of the most important factors for assessing the quality and acceptability of food. However, the study of food texture has been delayed compared with other factors, such as flavor and taste, due to the difficulty of quantitative analysis related to real physiological senses. Furthermore, the numerical and systematic evaluation of the texture property of dispersion systems, in which solid particles are dispersed in a liquid medium, is very difficult, despite most foods being in a solid–liquid dispersion state during mastication in the human mouth. In this study, the texture property of a solid–liquid dispersion system with spherical and cubic gel particles of agar and konjac was examined to evaluate the physical behavior of food during mastication using the back extrusion method. The yield stress of the system strongly depended on the size and shape of the particles, the mixing ratio of particles of different sizes and shapes, and the concentration of components in the particles. The proposed index, reflecting the size, shape, and number of particles and the yield stress of a single particle, expressed well the measured yield stress of the entire dispersion system. However, the adhesiveness and recoverability showed relatively little dependence on particle size. The findings obtained in this study will contribute to elucidating the texture property of various foods and to the development of new and novel food products and cuisines, thereby benefiting food science and industry. [ABSTRACT FROM AUTHOR]

This study investigates the forces exerted on organs during swallowing, specifically focusing on identifying forces other than those resulting from direct organ contact. Using a swallowing simulator based on the moving particle method, we simulated the swallowing process of healthy individuals upon the ingestion of thickened foods, which were simulated as shear‐thinning flow without yield stress. We extracted the resultant force vectors acting on the organs and shape of the bolus at each time interval. The simulation results confirmed that the bolus originates from tongue movement and is transferred between the oral cavity and pharynx, with each organ's coordinated movements with the tongue occurring at their respective positions, as indicated by the balance of the resultant force vectors. Utilizing the information about the resultant force vectors obtained through simulations, we calculated the physical parameters of impulse, energy, and power. The variations in these physical parameters were aligned with the behaviors of both the biological system and the food bolus during swallowing. The force values calculated from the simulations closely approximate the theoretical values. Furthermore, the forces calculated from the simulations were relatively smaller than the force values derived from pressure information, such as that from high‐resolution manometry and tongue pressure sensors. This difference can be attributed to the simulations extracting only the forces exerted on the organ by the food bolus. Force information on organs has the potential to provide a new interpretation of conventional mechanical indicators such as manometry and tongue pressure sensors. [ABSTRACT FROM AUTHOR]

This paper presents an elastoplastic model to estimate the hydromechanical behavior of unsaturated soils based on state boundary hypersurface. Through mechanical hypersurface, the influence of saturation on yield stress can be expressed in a full form rather than an incremental form. Two hydraulic hypersurfaces and one mechanical hypersurface are proposed to establish the model. Two hydraulic hypersurfaces, composed of degree of saturation, void ratio and matrix suction, define the plastic hydraulic boundary. The elastic hydraulic behavior of unsaturated soils can be represented by scanning lines between these two hydraulic hypersurfaces. The mechanical hypersurface, composed of degree of saturation, void ratio and effective stress, defines the plastic mechanical boundary. The elastic mechanical behavior of unsaturated soils can be represented by scanning lines below the mechanical hypersurfaces. A large number of laboratory tests are used to validated the proposed model, showing that it can reasonably capture important features of the hydromechanical behavior of unsaturated soils. [ABSTRACT FROM AUTHOR]

Oil sands tailings ponds are significant emitters of greenhouse gases (GHGs) in Canada. To move beyond making surface or atmospheric measurements of GHG release, it is necessary to understand the physical mechanisms by which gas is generated, bubbles form and then are either released or remain trapped in the pond. We present a review of the physical description of tailings ponds, relevant to gas release models. In particular, we target rheological variations within a pond and how these directly affect the distribution of trapped gas bubbles with depth. Within the limits of the available data, we show how gas content may vary significantly across ponds, and develop data-driven one-dimensional models of gas distribution and rheology. [ABSTRACT FROM AUTHOR]

In this research paper, the effect of the addition of copper (0.02 to 3.32 wt.%) on microstructure, mechanical and thermal properties of Al-Zn-Mg alloy are studied using an optical microscope, scanning electron microscope (SEM), X-ray diffractometer (XRD), Vicker's microhardness tester, universal testing machine (UTM) and differential scanning calorimeter (DSC). Precipitates (η-MgZn2 phases) are present in as-cast Al-Zn-Mg alloy. SEM and XRD analyses have shown the presence of η (MgZn2) and θ (Al2Cu) precipitate in the as-cast Al-Zn-Mg-Cu alloy. Micro-Vickers hardness increases from 121.3 HV1 to 153.1 HV1 for the initial increase in copper content (0.02 to 1.54 wt.%) and then decreases to 137.3 HV1 (3.32 wt.% copper). The melting point decreases continuously with increased copper content from 619.8 °C (0.02 wt.% Cu) to 608.5 °C (3.32 wt.% Cu). Peak compressive stress, absorbed energy per unit volume, yield stress is observed to increase by 43.6%, 75.4%, and 59.3%, respectively, for the rise in copper content (0.02 wt.% to 1.54 wt.%) in the alloy. [ABSTRACT FROM AUTHOR]

To investigate the effects of different pore water environments on compressive behaviours of the deep-sea soft soil from South China Sea, four kinds of soil samples including natural sample with sea water or deionized water, remolded sample with sea water or deionized water were prepared, respectively. Then, a series of oedometer tests and scanning electron microscopy tests were performed on the above samples to examine their compressive behaviours and microscopic characteristics, respectively. Additionally, the microscopic pore distribution of natural sample with sea water was observed by mercury intrusion porosimetry tests. The effects of different water environments on macroscopic compressive behaviours and microscopic particle characteristics are analyzed. The deionized water environment increases the compressibility and decreases the consolidation coefficient for natural samples after structural breakage and remolding. The microscopic particle characteristics corresponding to the macroscopic compressibility are also qualitatively analyzed. In deionized water environment, soil particles exhibit higher roundness, more orderly and lower surface roughness than that in seawater environment. In this study, the deionized water environment has no obvious effect on the structural yield stress and secondary consolidation coefficients of deep-sea soft soil. [ABSTRACT FROM AUTHOR]

Concentrated emulsions and foams and microgels are comprised of deformable particles making these materials display complex rheological behavior that includes a yielding transition from an elastic solid to viscous fluid. Most studies of this class of soft matter involve shear flows and only a few report both shear and normal stresses. Here, we report measurements of the shear stress and two normal stress differences for a Carbobol microgel, which is usually classified as simple yield stress fluid, subjected to constant shear rate flows. Similar to our previous study, the shear stress evolves through the yield point in a manner indicative of simple yield stress fluid behavior while the normal stress differences evolve in a reproducibly chaotic manner. We also find that the evolution of the stresses is dependent on the whether the microgel has been in a state of relaxation or recovery prior to the measurement. [ABSTRACT FROM AUTHOR]

Locomotion at small scales in the absence of inertia is a classical and enduring research topic. Here, recent developments in the theory of such locomotion through a viscoplastic ambient fluid are reviewed and explored. The specific focus here applies to motion of cylindrical filamentary bodies that are long and thin, for which an asymptotic slender-body theory can be exploited. Details of this theory are summarised and then applied to describe different swimming waveforms: undulation, peristalsis, and helical motion. It is shown that, in general, strong force anisotropy close to the limit of axial cylindrical motion has a significant effect on locomotion in viscoplastic media, allowing for highly efficient motion in which the swimmer is able to 'cut' through the material following very closely the path of its own axis. Some qualitative comparison with experiments is presented, and future extensions and research directions are reviewed. Deformation fields around cylinders moving at different angles to their axis through a yield stress fluid, showing (a) a low yield stress and (b) a high yield stress [ABSTRACT FROM AUTHOR]

The dynamic yield stress associated with the flow cessation of cement pastes is measured using a rheometer equipped with various shear geometries such as vane, helical, sandblasted co-axial cylinders, and serrated parallel plates, as well as with the mini-cone spread test. Discrepancies in yield stress values are observed for cement pastes at various volume fractions, with one to two orders of magnitude difference between vane, helical and mini-cone spread measurements on the one hand, and co-axial cylinder and parallel plate measurements on the other hand. To understand this discrepancy, the flow profile of a cement paste in the parallel-plate geometry is investigated with a high-speed camera, revealing the rapid formation of an un-sheared band near the static bottom plate. The width of this band depends upon the rotational velocity of the top plate, and upon the shear time. Recalculation of shear stress shows that the reduced sheared gap alone cannot explain the low measured yield stress. Further exploration suggests the formation of zones with lower particle content, possibly linked to cement particle sedimentation. Here, we argue that the complex nature of cement pastes, composed of negatively buoyant non-Brownian particles with attractive interactions due to highly charged nano-size hydration products, accounts for their complex rheological behavior. [ABSTRACT FROM AUTHOR]

Integrating grain yield, component traits and metabolite profiles aids in selecting drought‐adapted and climate‐smart crop varieties preferred by end users. Understanding the trends and magnitude of grain‐based metabolites is vital for selecting wheat genotypes with higher grain yield, drought tolerance, water use efficiency and product profiles. The aim of this study was to determine the response of newly developed wheat genotypes for grain yield and component traits and metabolites under drought stress to guide selection. One hundred wheat genotypes were preliminarily evaluated for agro‐morphological traits and water use efficiency under drought‐stressed and non‐stressed conditions during the 2022 and 2023 growing seasons using a 5 × 20 alpha lattice design with two replications. Ten high‐yielding genotypes were selected based on grain yield and were validated for agronomic traits and water use efficiency (WUE), and grain samples were assayed to profile their key metabolites under drought‐stressed conditions. Significant differences existed (p < 0.05) among the tested wheat genotypes for yield and yield components, WUE, drought tolerance and major metabolites to discern trait associations. The grain yield of the 10 genotypes ranged from 590.00 g m−2 (genotype LM70 × BW140) to 800.00 g m−2 (BW141 × LM71) under drought‐stressed treatment, whilst under non‐stressed it ranged from 760.06 g m −2 (LM70 × BW140) to 908.33 g m−2 (LM71 × BW162). Grain yield‐based water use efficiency of the assessed genotypes was higher under non‐stressed (0.18 g mm−1) than drought‐stressed (0.17 g mm−1) conditions. The highest drought tolerance index (211.67) and stress susceptibility index (0.77) were recorded for BW162 × LM71, whilst the lowest tolerance index (23.33) and stress susceptibility index (0.09) were recorded in BW141 × LM71. Grain metabolites, including the apigenin‐8‐C‐glucoside (log2Fold = 3.00) and malate (log2Fold = 3.60) were present in higher proportions in the high‐yielding genotypes (BW141 × LM71 and LM71 × BW162) under drought‐stressed conditions, whilst fructose (log2Fold = −0.50) and cellulose (log2Fold = −3.90) showed marked decline in the two genotypes. Based on phenotypic and metabolite profile analyses, genotypes BW141 × LM71 and LM71 × BW162 were selected for being drought‐tolerant, water‐use efficient and recommended for production or breeding. The findings revealed associations between yield components, water use efficiency and grain metabolites to guide the selection of best‐performing and drought‐tolerant wheat varieties. [ABSTRACT FROM AUTHOR]

Waterlogging affects a high proportion of cultivated land worldwide. Sunflower, soybean and sorghum growth and yield can be affected differently depending on the moment and duration of waterlogging stress. If stress conditions occur during the critical period for yield potential definition (flowering in, sunflower and sorghum and end of pod formation in soybean) they directly reduce grain number, but if the stress occurs during the grain‐filling period, grain weight would be affected. The aim of this study focuses on determining the effects of the moment and duration of waterlogging stress on the yield and its components in sunflower, soybean and sorghum. This information will be useful to understand the effects of waterlogging on yield and to choose a suitable crop or sowing date based on predicted weather conditions for a certain place. To achieve this objective, four experiments were conducted at the Experimental Station of INTA (Reconquista, Santa Fe, Argentina). The effect of the waterlogging in terms of moment (vegetative, critical and grain‐filling periods) and duration (3, 7 and 10 days) on the three crops was evaluated. Sunflower expressed the most negative impact of waterlogging during the vegetative stages (26, 78 and 98% of yield losses with 3, 7 and 10 days, respectively) while soybean suffered major reductions when the stress occurred during the critical period (5%–17% of yield loses). Sorghum did not express any negative responses for the moments and durations tested. This study suggests that the critical period for a waterlogging event differs, according to crops, from the critical period cited for other stresses. Moreover, the magnitude of the damage will mainly depend on the duration of the event. Further studies are needed to elucidate different physiological responses of the species during waterlogging stress. [ABSTRACT FROM AUTHOR]

Identifying the genomic regions (quantitative trait loci (QTL)) significantly linked to grain yield under drought stress could expedite the development of novel rice cultivars suited for rainfed areas through marker‐assisted breeding. This study identified QTL regions linked to plant phenology and production traits by evaluating 122 recombinant inbred lines (RILs) of Danteshwari × Daggaddeshi under different environmental conditions. A consistent QTL region associated with grain yield under water stress (60.4 Mbp) was mapped on chromosome 1 between RM428 and RM24 with an LOD score of 4.0. Another QTL region (9.4 Mbp) linked to plant height under all environmental conditions was mapped on chromosome 1 between RM1‐HvSSR1‐87 with a LOD score of 7.5 and phenotypic variance of 25%. A core set of 402 diverse rice accessions was also evaluated under water stress conditions and subjected to genome‐wide association analysis. Twelve markers linked to grain yield under drought were identified, out of which five were significantly associated with grain yield and days to flowering under drought. The markers linked to grain yield were compared between the bi‐parental population and germplasm accessions to identify the common markers. Three markers (RM1, RM259 and RM201) were found to be consistently linked to drought stress across the seasons in both bi‐parental population and germplasm accessions studied and could be potential candidates for application in marker‐assisted selection for improving grain yield under drought stress in rice. [ABSTRACT FROM AUTHOR]

• Lumbopelvic distance reduction enhances stability after total sacrectomy. • Lumbopelvic distance reduction lowers the bone-implant and rod stress. • All reconstruction techniques are suitable for lumbopelvic stabilization. • Regardless of the used technique, LPDR is biomechanically advantageous. Following total sacrectomy, lumbopelvic reconstruction is essential to restore continuity between the lumbar spine and pelvis. However, to achieve long-term clinical stability, bony fusion between the lumbar spine and the pelvic ring is crucial. Reduction of the lumbopelvic distance can promote successful bony fusion. Although many lumbopelvic reconstruction techniques (LPRTs) have been previously analyzed, the biomechanical effect of lumbopelvic distance reduction (LPDR) has not been investigated yet. To evaluate and compare the biomechanical characteristics of four different LPRTs while considering the effect of LPDR. A comparative finite element (FE) study. The FE models following total sacrectomy were developed to analyze four different LPRTs, with and without LPDR. The closed-loop reconstruction (CLR), the sacral-rod reconstruction (SRR), the four-rod reconstruction (FRR), and the improved compound reconstruction (ICR) techniques were analyzed in flexion, extension, lateral bending, and axial rotation. Lumbopelvic stability was assessed through the shift-down displacement and the relative sagittal rotation of L5, while implant safety was evaluated based on the stress state at the bone-implant interface and within the rods. Regardless of LPDR, both the shift-down displacement and relative sagittal rotation of L5 consistently ranked the LPRTs as ICR

Hemodynamic analysis reveals a highly significant effect on the prevention, diagnosis, and treatment of human vascular diseases. This article goes deeply into the periodic pulsatile blood flow in the carotid artery with an elastic vessel wall. In view of blood rheological experimental data, the constitutive equation of fractional Maxwell power-law fluid with yield stress, which can describe the four characteristics of yield stress, viscoelasticity, shear thinning, and thixotropy is established. Meanwhile, drawing support from the data of pulsatile flow, the finite Fourier series of pressure gradient with a period of 1 s has been proposed. Leading into Hooke's law can build the fluid-structure coupling boundary condition of blood flow and elastic vessel wall. The numerical solutions are got hold of finite difference method integrated with the newly developed L1-algorithm, and their convergence and stability of which are verified. The axial velocities of blood under different constitutive relationships are compared. The results throw light that other constitutive relationships underestimate the velocity of blood. Furthermore, the flow rate and wall shear stress on different fluid are calculated. It can be concluded that compared with Bingham fluid, the maximum and minimum flow rate/wall shear stress of fractional Maxwell power-law fluid with yield stress increases by 19% and 32%, respectively. The flow rate lags behind the pressure gradient and has time delay effect, on the contrary, the velocity of blood vessel wall is keeping pace with the pressure gradient. The effects of relevant physical parameters on velocity are discussed. In addition, the spatiotemporal distribution of blood flow in cerebral artery and femoral artery are analyzed. HIGHLIGHTS: Fractional Maxwell power-law fluid is proposed to describe hemorheology property. Based on Hooke's law, the boundary condition of elastic wall is established. The finite Fourier series of pulsating pressure gradient has been fitted firstly. Blood flow promoted by the pressure gradient has a hysteresis effect. The velocity of blood vessel wall is keeping pace with the pressure gradient. [ABSTRACT FROM AUTHOR]

Heat and drought stress, which often co-occur due to water evaporation, are two major abiotic factors limiting the production of rice (Oryza sativa L.) It is crucial to enhance understanding of the effects of these abiotic stresses in rice, particularly for rice-producing countries like Malaysia, which has yet to achieve rice selfsufficiency. This greenhouse study was conducted to evaluate the morphological changes of two important Malaysian cultivars (‘MR219’ and ‘MR303’) at vegetative, reproductive, and ripening stages, as well as their physiological response and yield components under normal (control), heat, drought, and combined heatdrought stress conditions. Individual heat stress greatly influenced rice growth and yield, with significant differences (p < 0.01) observed across all examined parameters except the grain to leaf area index ratio (GtoLAI). Conversely, individual drought stress mostly affected yield-related parameters, with significant differences (p < 0.01) in grain weight (GW), harvest index (HI), and percentage of filled grain (%FG). Interestingly, the combined stresses in this study did not significantly affect plant height (PH) for all growth stages and most yield-related traits (HI, GW, and GtoLAI). The majority of the significant changes (p < 0.01) were observed on physiological traits, including chlorophyll a (Chl A) and b (Chl B). We found a positive correlation between HI and %FG (R² = 0.3974**) under heat and drought stress, indicating that improving either of these traits can boost rice production. Collectively, our study revealed that the individual effects of heat and drought on rice growth and yield can differ from the effects of combined stress. [ABSTRACT FROM AUTHOR]

At present, in the directed energy deposition (DED) of metals, the heat transfer of the melt pool and microstructural evolution are not fully understood. This study investigates the thermal effect on the microstructure and the mechanical properties of DED AISI 316L, using in situ optical monitoring. Five thin-wall samples were tested to determine the effect on microstructural evolution and mechanical properties with variable laser powers and scanning speeds. A comprehensive optical monitoring system with a CMOS (coaxial complementary metal oxide semiconductor) visual module and an infrared camera was adopted in analyzing the temperature gradient and the solidification rate. The emissivity of the melt pool was calibrated, using the melt pool length, extracted from the coaxial visual image. The results showed that microstructures mainly consist of the coarse columnar grain and the equiaxed grain at the top layer of AISI 316L samples. The direction of epitaxial growth of columnar grains is affected by the compromise between directional heat flux and crystallographic direction. High numerical temperature gradient and high solidification rate are beneficial to obtaining fine grain size and high yield stress. A modified microstructure map for DED AISI316L was established, which correlates the solidification parameters with a solidification microstructure. This research study, combining temperature distribution, solidification parameter, microstructure, and tensile property, provides an experimental identification of solidification parameters and the model on the solidification theory for precision control of DED process. [ABSTRACT FROM AUTHOR]

Droplet deposition with material-jetting methods such as thermoplastic 3D printing (T3DP) depends greatly on the rheological properties of the feedstocks. This study investigated the effect of particle interactions and the degree of weak flocculation on the shear thinning behaviour, the yield stress and the storage/loss moduli of paraffin-wax-based feedstocks containing 40 vol% of zirconia (3Y-TZP) micron-sized powder. Steric stabilization of the feedstocks was provided by varying the ratios of the surfactants with different chain lengths, i.e., stearic acid (2.4 nm) and Solsperse 3000® (10 nm), which in turn affected the dynamics of the droplet formation and the quality of the layers when jetting non-Newtonian, thermoplastic ceramic feedstocks. The results of the study extend the guidelines for the processing of printable feedstocks used in T3DP additive manufacturing. • Steric stabilization of ceramic particles can be controlled by using surfactants. • Shorter surfactant chain length leads to higher total attractive potential energy. • Higher total attractive potential energy means higher viscosity and yield stress. • Feedstocks with shear thinning and no yield point are well suited for T3DP. • Interparticle interactions affect the quality of printed droplets and parts. [ABSTRACT FROM AUTHOR]

Background: Residual stresses exist in many manufactured materials and must be measured and taken into account for safe structural design. Established residual stress measurement methods are either destructive or require substantial material-dependent calibration. Objective: The present work is aimed at developing an indentation-based method for measuring residual stress that causes minimal specimen damage, does not require a stress-free reference specimen, and has the capability to identify both the size and direction of the surface residual stresses. In this initial study, the simpler case of equi-biaxial stresses is addressed in preparation for subsequent general stress evaluations. Methods: The surface displacements around an indentation made by a conical indenter are measured using digital image correlation. The residual stresses are then identified by comparison to the results of a finite model of the indentation process. Results: The proposed method is shown to 2–5 times more sensitive to the presence of residual stresses than other commonly used indentation methods, particularly for materials with low Hollomon exponent n. In example measurements, axi-symmetric residual stresses were determined within 8% of the material yield stress. Conclusions: The initial study presented here successfully considered the equal-biaxial stress case. The proposed method is attractive for future development because it gives directional information and therefore can be extended to the general non-equal-biaxial case. [ABSTRACT FROM AUTHOR]

Loess is the most well-known collapsible soil. The field immersion test is one of the effective means to assess the in situ self-weight collapsibility of soil. However, the reason why huge differences appeared in collapse settlements in different regions remains unclear, and which factors largely determine the amount of collapse deformation of loess during field immersion tests are worthy of being discussed. In this study, a numerical model for hydromechanical (HM) behaviors of loess was developed, in which the effects of the porosity on the water retention behavior and intrinsic permeability were incorporated. A field immersion test associated with the monitored collapse settlement, water retention curve measurements, and the variation of self-weight collapsibility with depth were used to testify to the effectiveness of the numerical model. The model was then adopted to clarify the effects of compression index, initial suction, and yield stress on the coupled HM or collapse settlement behavior of loess in field immersion tests. The aforementioned three parameters are relatively easy to be determined from various sites and have obvious differences. Then, a total of 126 numerical cases were conducted by the HM model, with the range of the collapse settlement from 0.334 m to 1.136, which covers the most range of the collapse settlement of the field immersion test systematically summarized by previous researchers. The result shows that yield stress and compression index have a significant influence on collapse settlement. The initial suction has a slight influence on collapse settlement, which mainly affects the velocity of water transport. The model herein can be used in the assessment of the in situ collapsibility of loess, and when the basic physical properties of a site are determined, the numerical simulation database of this study can preliminarily determine the site's collapsibility grade and amount of the collapsibility. [ABSTRACT FROM AUTHOR]

In this study, the yield stress equation, flow rules and physical properties of barium titanate (BaTiO3) are experimentally obtained. These basic equations and coefficient of flow stress are introduced to finite element method, and sintering behavior of barium titanate bulk is simulated. From the uniaxial compression test, the yield stress equation of BaTiO3 is expressed by Shima's equation, and flow rule is written by plastic equation. The coefficient of flow stress of BaTiO3 is significantly smaller than that of alumina, and the value is different when the grain size is different. The experimental sintering deformation is quantitatively reproduced by numerical simulation, where basic equation and physical properties are experimentally introduced. In addition, the coefficient of flow stress could be determined by simulation sensitivity analysis. Through this study, experimentally obtained yield stress equation, flow rules, and coefficient of flow stress are numerically validated. [ABSTRACT FROM AUTHOR]

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

EN-GJS-400-15U nodular cast iron intended to be used as load-bearing element in long-term geological disposal canisters containing spent nuclear fuel in Finland and Sweden was studied for static strain aging (SSA). Tensile test specimens manufactured from the nodular cast iron were pre-strained to 1%, 2% and 3% nominal plastic strains. The pre-strained specimens were aged at different temperatures ranging from room temperature to 400 °C for varying times. The aged specimens were tested with conventional tensile testing using constant cross-head speed of 0.016 mm/s. Additionally, four specimens were studied with digital image correlation (DIC) during the tensile testing to obtain full-field strain measurements. SSA resulted in elevated pronounced yield point in all the conditions, while the as-received material showed continuous yielding behavior. SSA reduced the elongation to fracture. DIC tests showed more localized yielding behavior in the SSA specimens. Over-aging effect was observed at 400 °C where increasing pre-strain did not increase the yield stress more. For 1-day aging time, the highest yield stress increment was found after aging at 200°C. The yield stress of the material was almost identical after aging in 100°C and 200°C. [ABSTRACT FROM AUTHOR]

In this paper, the Hu 2003 plasticity criterion performance is assessed against an experimental database, and a comparison is made with two variants of Hill 48 criterion for 10 different materials, mainly through the examination of the yield stress and anisotropy coefficients evolutions and the calculation of precision indices. The results show that the Hill 48-R and Hu criteria demonstrate superior performance with the latter also showing a good compromise in predicting both σ θ and R θ behavior reasonably well. Furthermore, the occasional oscillatory nature of Hu's criterion for certain materials is confirmed. Subsequently, a global sensitivity analysis using the variational approach proposed by Sobol is conducted on the formulation σ θ of the Hu criterion. The aim is to understand its occasional oscillatory behavior and identify the significant inputs in relation to this phenomenon. Through this analysis, the preponderant effects of certain parameters, particularly σ b and R 45 , on the criterion's oscillation are elucidated. This study also provides insights into the applicability range of the Hu 2003 criterion. [ABSTRACT FROM AUTHOR]

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

The comparative chloride stress corrosion cracking (Cl-SCC) susceptibility for 304 L, 316 L, 317 L, and AL-6XN was evaluated using double cantilever beam (DCB) specimens in boiling MgCl2 by measuring the threshold stress intensity (KISCC), crack initiation time, and stage-II crack growth rate (CGR) for each material using in situ monitoring. Materials 304 L, 316 L, and 317 L were measured to have KISCC upper limit values of 2.5–5 MPa√m, substantially lower than previously measured for 304 L in DCB specimens in boiling MgCl2. The KISCC for AL-6XN was measured to be substantially higher, as would be expected in this more highly alloyed material. This work describes the challenge in measuring low KISCC values and how this was accomplished in the present work. More prototypical conditions were used to evaluate Cl-SCC behavior of 304 L using a DCB-like geometry with a smooth gauge area in a low humidity environment in the presence of MgCl2 salt. Finite element modeling (FEM) was used to establish the relationship between applied loads and stress and strain. Loading to 15 % strain led to low temperature creep that masked in situ Cl-SCC measurements. Below the yield stress (YS), no low temperature creep was observed, and Cl-SCC cracking could be distinguished using in situ methods. [ABSTRACT FROM AUTHOR]

The article presents investigations of microstructure and low‐temperature mechanical properties of nanostructured alloys CoCrFeMnNiVx (x = 0.15–0.75), processed by high‐pressure torsion (HPT) at temperatures of 300 and 77 K. While at x ≥ 0.5 the values of microhardness (Hv) and compression yield stress (σ0.2) in samples after HPT at 77 K are larger than those in samples after HPT at 300 K, for x ≤ 0.2 surprisingly the opposite effect is observed. As in case of the undeformed CoCrFeMnNiVx alloys, the behavior for vanadium concentrations x ≥ 0.5 can be related to the formation of tetragonal σ‐phase in addition to face‐centered cubic matrix, while the anomalous behavior for x ≤ 0.2 arises from the formation of HPT‐induced hexagonal martensitic phase. In the low‐temperature ranges, i.e., 20–300 K in case of HPT nanostructured CoCrFeMnNiV0.2, and 150–300 K in case of HPT nanostructured CoCrFeMnNiV0.5, dependences of σ0.2(T) show characteristics of thermally activated dislocation movement. For the first time in high‐entropy alloys, anomalous dependences of σ0.2(T) at temperatures 4.2–20 K for CoCrFeMnNiV0.2, and at 80–150 K for CoCrFeMnNiV0.5 are found, which indicate at the occurrence of nonthermal inertial dislocation movement. [ABSTRACT FROM AUTHOR]

The present work takes a new look at the high temperature strength of single crystal (SX) Ni‐base superalloys. It compares high temperature constant strain rate (CSR) testing, creep testing, and out‐of‐phase thermomechanical fatigue (OP TMF) testing, which represent key characterization methods supporting alloy development and component design in SX material science and technology. The three types of tests are compared using the same SX alloy, working with precisely oriented <001>‐specimens and considering the same temperature range between 1023 and 1223 K, where climb controlled micro‐creep processes need to be considered. Nevertheless, the three types of tests provide different types of information. CSR testing at imposed strain rates of 3.3 × 10−4 s−1 shows a yield stress anomaly (YSA) with a YSA stress peak at a temperature of 1073 K. This increase of strength with increasing temperature is not observed during constant load creep testing at much lower deformation rates around 10−7 s−1. Creep rates show a usual behavior and increase with increasing temperatures. During OP‐TMF loading, the temperature continuously increases/decreases in the compression/tension part of the mechanical strain‐controlled cycle (±0.5%). At the temperature, where the YSA peak stress temperature is observed, no peculiarities are observed. It is shown that OP‐TMF life is sensitive to surface quality, which is not the case in creep. A smaller number of cycles to failure is observed when reducing the heating rate in the compression/heating part of the mechanical strain‐controlled OP‐TMF cycle. The results are discussed on a microstructural basis, using results from scanning and transmission electron microscopy, and in light of previous work published in the literature. [ABSTRACT FROM AUTHOR]

In most Ni-free Ti-Nb- and Ti-Zr-based superelastic alloys, large amounts of high-cost and rare elements such as Nb, Ta, Hf and/or Zr are contained, increasing the cost and fabrication difficulty of the alloy. Here, new low-alloy content Ti-Mo-Zr-Sn-Al alloys are developed with large room temperature superelasticity and narrow stress hysteresis for potential biomedical applications. A good combined performance of yield stress (477 MPa) and small stress hysteresis (117 MPa) is achieved at room temperature in Ti-8Mo-6Zr-6Sn-5Al (wt%) alloy showing a recovery strain of 4.4%, which has not been obtained in previously reported Ni-free Ti-Nb, Ti-Zr and Ti-Mo-based superelastic alloy. [ABSTRACT FROM AUTHOR]

The effects of an addition of 4 wt pct V on the mechanical properties and microstructure of a Ti–4Al–3Cu–2Fe (wt pct) alloy manufactured by extrusion of compacts of TiH2/Al/Cu/Fe powder blend followed by vacuum annealing were investigated. It was found that the V addition changed the microstructure of the alloy from lamellar structure to basket-wave structure, increased the volume fraction of β phase from 47 to 53 pct, and reduced the average α lamella thickness significantly from 4.0 to 1.5 μm. Surprisingly, these compositional and microstructural changes cause only a small increase of the yield stress (from 1132 to 1151 MPa) and elongation to fracture (from 6.1 to 6.5 pct), but the strain hardening rate of the alloys are substantially enhanced over a narrow strain range of 0.9-1.7 pct, leading to a clear increase of the ultimate tensile strength from 1184 to 1252 MPa. The main mechanism for the microstructural changes caused by the V addition is the enhanced stabilization of β phase by V atoms and the growth restriction of α lamellae by V partitioning between α and β phases. The enhancement of strain hardening rate can be attributed to the enhance the number density of the α/β interfaces associated with the decrease of the α lamella thickness and which provides more effective barriers for the movement of dislocations. [ABSTRACT FROM AUTHOR]

Waterlogging is expected to become a more prominent yield restricting stress for barley as rainfall frequency is increasing in many regions due to climate change. The duration of waterlogging events in the field is highly variable throughout the season, and this variation is also observed in experimental waterlogging studies. Such variety of protocols make intricate physiological responses challenging to assess and quantify. To assess barley waterlogging tolerance in controlled conditions, we present an optimal duration and setup of simulated waterlogging stress using image-based phenotyping. Six protocols durations, 5, 10, and 14 days of stress with and without seven days of recovery, were tested. To quantify the physiological effects of waterlogging on growth and greenness, we used top down and side view RGB (Red-Green-Blue) images. These images were taken daily throughout each of the protocols using the PSI PlantScreen™ imaging platform. Two genotypes of two-row spring barley, grown in glasshouse conditions, were subjected to each of the six protocols, with stress being imposed at the three-leaf stage. Shoot biomass and root imaging data were analysed to determine the optimal stress protocol duration, as well as to quantify the growth and morphometric changes of barley in response to waterlogging stress. Our time-series results show a significant growth reduction and alteration of greenness, allowing us to determine an optimal protocol duration of 14 days of stress and seven days of recovery for controlled conditions. Moreover, to confirm the reproducibility of this protocol, we conducted the same experiment in a different facility equipped with RGB and chlorophyll fluorescence imaging sensors. Our results demonstrate that the selected protocol enables the assessment of genotypic differences, which allow us to further determine tolerance responses in a glasshouse environment. Altogether, this work presents a new and reproducible image-based protocol to assess early stage waterlogging tolerance, empowering a precise quantification of waterlogging stress relevant markers such as greenness, Fv/Fm and growth rates. [ABSTRACT FROM AUTHOR]

Thermal interface materials (TIMs) paly an indispensable role in improving overall performance of chip, due to the boom of cloud service, machine learning, and artificial intelligence. However, traditional TIMs tend to behave as liquid‐like or solid‐like features, which cannot meet the new requirement of both long‐term stability and excellent thermal‐conduction property. Here, a thermally conductive yield stress fluid consisting of phenyl‐vinyl polydimethylsiloxane polymer and aluminum oxide fillers is reported. This material exhibits reversible liquid–solid transition with a yield‐stress value of 87.32 Pa, and low thermal resistance (0.16 K cm2 W−1). The reversible liquid–solid transition and low thermal resistance are both attributed to the formation of the filler network, as demonstrated by using rheology and two‐phase model. Furthermore, a unifying description of the liquid–solid transition is proposed based on a jamming phase diagram, by considering three factors including filler fraction, temperature, and stress. The yield‐stress fluids combine the desired dispensing due to their liquid‐like behavior and the excellent long‐term stability due to their solid‐like feature. An insight is further provided into the application of this yield‐stress fluids in high‐performance TIMs. [ABSTRACT FROM AUTHOR]