High Plasticity Research Articles

A novel heterogeneous particle addition method based on laser cladding hybrid wire arc additive manufacturing: improvement performance of stainless steel components

ABSTRACT The direct preparation of large components by laser cladding (LC) is not economical, but if it is used as a means of trace element addition and combined with the high efficiency advantages of wire arc additive manufacturing (WAAM), efficient manufacturing and high degree of freedom design of components can be achieved. In this study, high toughness and high plasticity stainless steel components were successfully prepared by combining WAAM and LC. The microstructure in the hybrid deposited specimens evolved into a single austenite, and the proportion of cubic and {001}<100 > textures increased. The mechanical properties obtained were significantly greater than those recommended for use by ASTM A479. The toughness of the hybrid deposited specimens was significantly improved, with a maximum increase in yield strength of 32%, exceeding 350 MPa. The elongation increased by a maximum of 12.7%, reaching 89.2% in the horizontal direction.

Polymer Concretes Based on Thermosetting Polymers: Technological, Physical, Mechanical Properties and Use in Construction

The article provides an analytical review of the main problems and prospects for the use and introduction of polymer concrete in modern construction industries. It was found that due to high plasticity, low porosity and the ability to quickly gain strength, polymer concretes are used for the manufacture of decorative products of small architecture, structural load-bearing and decorative overhead parts, decorative paving tiles and paving stones, products for hydrotechnical purposes, etc. by methods of vibration molding and casting. The classification of polymer concretes used in modern construction industries is provided, as well as an idea of the properties of the most popular polymer concretes based on thermosetting polymers – furan, epoxy and polyester. The advantages and disadvantages of known polymer concretes and the main promising directions of implementation for the manufacture of building products and structures are given. Attention is focused on the influence of the qualitative and quantitative composition of polymer concrete, the nature of the thermosetting polymer binder, the type of fillers and aggregates, the terms of hardening, the degree of polymerization on the most important physical, mechanical and technological properties of the finished materials.

Utilizing Magnesium Carbonate Induced by CO2 to Modify the Performance of Plastic Clay

Highly plastic clays pose significant challenges in engineering projects. Various techniques have been employed to enhance their properties, though many face difficulties related to implementation and environmental impact. This study examines the effect of CO2-induced magnesium carbonate on improving the geotechnical behavior of plastic clay. CO2-induced magnesium carbonate was produced via mineral carbonation and used to improve the behavior of highly plastic natural clay. CO2 gas was injected into a sodium hydroxide solution to produce carbonate ions (CO32−). Magnesium carbonate was precipitated on a laboratory scale by adding magnesium sulfate solution to the carbonate ion solution. Clayey soil samples were obtained from test pits in the Meyghan Plain near Arak, Iran. The clay samples were treated with different percentages of the produced magnesium carbonate. Various parameters of the treated and untreated samples, including index properties, unconfined compressive strength, consolidation behavior, and swelling potential, were studied. It was found that the liquid limit and plasticity index of the treated clay decreased as the magnesium carbonate content increased. The soil classification changed from high plastic clay (CH) to low plastic silt (ML) with the addition of 15% magnesium carbonate to the highly plastic clay. The unconfined compressive strength of the treated clay increased. Additionally, the consolidation behavior and swelling index of the treated clay improved as the magnesium carbonate content increased. This study confirms that CO2-induced magnesium carbonate is a promising material for improving the behavior of highly plastic clays, offering a sustainable approach to environmental management.

Treatments Technology and Mechanisms of East Asia Black Cotton Soil

The East Asia black cotton soil (BCS) cannot be used as embankment filling directly due to its high clay content, liquid limit, plasticity index, and low CBR strength (CBR &lt; 3%). This study evaluates the effects of treating East Asia BCS with lime, volcanic ash, or a combination of both on its engineering properties. Experiments were conducted to analyze the basic physical properties, swelling characteristics, and mechanical properties of the treated soil. Results indicate that lime addition significantly reduces the free swelling rate, improves limit moisture content, increases optimum moisture content, decreases maximum dry density, and enhances CBR value. Although volcanic ash also improves BCS performance, its effects are less pronounced than those of lime. The combined treatment with lime and volcanic ash exhibits superior performance, greatly reducing expansion potential and significantly increasing soil strength. Specifically, a mixture of 3% lime and 15% volcanic ash optimizes the liquid limit, plasticity index, and CBR value to 49.2%, 23.8, and 24.7%, respectively, meeting the JTG D30-2015 requirements and reducing construction costs. The treatment mechanisms involve hydration exothermic reactions, volcanic ash reactions, and semipermeable membrane effects, which collectively enhance the soil’s properties by producing dense, high-strength compounds.

Neurophysiological markers of motor compensatory mechanisms in early Parkinson's disease.

Compensatory mechanisms in Parkinson's disease are defined as the changes that the brain uses to adapt to neurodegeneration and progressive dopamine reduction. Motor compensation in early Parkinson's disease could, in part, be responsible for a unilateral onset of clinical motor signs despite the presence of bilateral nigrostriatal degeneration. Although several mechanisms have been proposed for compensatory adaptations in Parkinson's disease, the underlying pathophysiology is unclear. Here, we investigate motor compensation in Parkinson's disease by investigating the relationship between clinical signs, dopamine transporter imaging data and neurophysiological measures of the primary motor cortex (M1), using transcranial magnetic stimulation in presymptomatic and symptomatic hemispheres of patients. In this cross-sectional, multicentre study, we screened 82 individuals with Parkinson's disease. Patients were evaluated clinically in their medication OFF state using standardized scales. Sixteen Parkinson's disease patients with bilateral dopamine transporter deficit in the putamina but unilateral symptoms were included. Twenty-eight sex- and age-matched healthy controls were also investigated. In all participants, we tested cortical excitability using single- and paired-pulse techniques, interhemispheric inhibition and cortical plasticity with paired associative stimulation. Data were analysed with ANOVAs, multiple linear regression and logistic regression models. Individual coefficients of motor compensation were defined in patients based on clinical and imaging data, i.e. the motor compensation coefficient. The motor compensation coefficient includes an asymmetry score to balance motor and dopamine transporter data between the two hemispheres, in addition to a hemispheric ratio accounting for the relative mismatch between the magnitude of motor signs and dopaminergic deficit. In patients, corticospinal excitability and plasticity were higher in the presymptomatic compared with the symptomatic M1. Also, interhemispheric inhibition from the presymptomatic to the symptomatic M1 was reduced. Lower putamen binding was associated with higher plasticity and reduced interhemispheric inhibition in the presymptomatic hemisphere. The motor compensation coefficient distinguished the presymptomatic from the symptomatic hemisphere. Finally, in the presymptomatic hemisphere, a higher motor compensation coefficient was associated with lower corticospinal excitability and interhemispheric inhibition and with higher plasticity. In conclusion, the present study suggests that motor compensation involves M1-striatal networks and intercortical connections becoming more effective with progressive loss of dopaminergic terminals in the putamen. The balance between these motor networks seems to be driven by cortical plasticity.

New Insights into the Exosome-Induced Migration of Uveal Melanoma Cells and the Pre-Metastatic Niche Formation in the Liver.

UM is an aggressive intraocular tumor characterized by high plasticity and a propensity to metastasize in the liver. However, the underlying mechanisms governing liver tropism remain poorly understood. Given the emerging significance of exosomes, we sought to investigate the contribution of UM-derived exosomes to specific steps of the metastatic process. Firstly, we isolated exosomes from UM cells sharing a common genetic background and different metastatic properties. A comparison of protein cargo reveals an overrepresentation of proteins related to cytoskeleton remodeling and actin filament-based movement in exosomes derived from the parental cells that may favor the detachment of cells from the primary site. Secondly, we assessed the role of macrophages in reprogramming the HHSCs by exosomes. The activation of HHSCs triggered a pro-inflammatory and pro-fibrotic environment through cytokine production, upregulation of extracellular matrix molecules, and the activation of signaling pathways. Finally, we found that activated HHSCs promote increased adhesion and migration of UM cells. Our findings shed light on the pivotal role of exosomes in pre-metastatic niche construction in the liver.

Stability Analysis of Borehole Walls When Drilling with Normal-Temperature Drilling Fluids in Permafrost Strata

Permafrost is a temperature-sensitive geological formation characterized by low elasticity and high plasticity. Inappropriate engineering design during borehole drilling in permafrost can result in the collapse of surrounding strata. To evaluate the stability of borehole walls, a finite element model was developed based on the inherent physical properties of permafrost. This model was utilized to investigate the thermal, stress, and plastic yield zone evolution around the borehole during drilling with normal-temperature fluids. The borehole expansion rate was employed as a quantitative measure to assess wall stability. The analysis reveals that the strata adjacent to the borehole, when drilled with normal-temperature fluids, experience thawing and yielding, with secondary stress concentrations in unthawed strata driving the progressive expansion of the plastic zone. The degree of plastic deformation diminishes with increasing distance from the borehole. Consequently, the borehole expansion rate was utilized to evaluate collapse risk under varying conditions, including permafrost thickness, depth, plastic strain thresholds, and drilling fluid densities. The findings suggest that normal-temperature drilling fluids are appropriate for thin permafrost layers, whereas for thicker permafrost, adjustments in drilling fluid density are required to ensure the stability of borehole walls due to the elevated temperatures and geostress at greater depths.

The thymus road to a T cell: migration, selection, and atrophy.

The thymus plays a pivotal role in generating a highly-diverse repertoire of T lymphocytes while preventing autoimmunity. Thymus seeding progenitors (TSPs) are a heterogeneous group of multipotent progenitors that migrate to the thymus via CCR7 and CCR9 receptors. While NOTCH guides thymus progenitors toward T cell fate, the absence or disruption of NOTCH signaling renders the thymus microenvironment permissive to other cell fates. Following T cell commitment, developing T cells undergo multiple selection checkpoints by engaging with the extracellular matrix, and interacting with thymic epithelial cells (TECs) and other immune subsets across the different compartments of the thymus. The different selection checkpoints assess the T cell receptor (TCR) performance, with failure resulting in either repurposing (agonist selection), or cell death. Additionally, environmental cues such as inflammation and endocrine signaling induce acute thymus atrophy, contributing to the demise of most developing T cells during thymic selection. We discuss the occurrence of acute thymus atrophy in response to systemic inflammation. The thymus demonstrates high plasticity, shaping inflammation by abrogating T cell development and undergoing profound structural changes, and facilitating regeneration and restoration of T cell development once inflammation is resolved. Despite the challenges, thymic selection ensures a highly diverse T cell repertoire capable of discerning between self and non-self antigens, ultimately egressing to secondary lymphoid organs where they complete their maturation and exert their functions.

Ultrastrong, high plasticity, and softening-resistant refractory high-entropy alloy via stable isostructural coherent interfaces

Traditional approaches for improving the mechanical performance of alloys entail modifying interfaces, particularly grain boundaries, with elemental segregation or secondary phases. However, these methods face challenges in concurrently improving the strength, plasticity, and high-temperature softening resistance of alloys. Here, we uncovered that stable isostructural coherent interfaces effectively address these challenges. In the model body-centered cubic (BCC) MoTaVW refractory high-entropy alloy (RHEA) fabricated by mechanical alloying and spark plasma sintering, controlling the sintering temperature enhances the preferential segregation of W at interfaces. This results in a distinct BCC W-enriched nanolayer between micrometer-scale grains. This nanolayer facilitates dislocation slip and prevents grain growth, thereby improving both plasticity and resistance to high-temperature softening. Consequently, the MoTaVW RHEA featuring stable isostructural coherent interfaces achieves an ultrahigh yield strength of 1410 MPa and a plasticity of 22 % at ambient temperature. Even at 1200 °C, it maintains a yield strength of 575 MPa under hot compression.

Study of the thermal stability of spent bleaching clay-based geopolymer with waste polypropylene plastic aggregates

This study incorporated polypropylene (PP) plastic waste into the spent bleaching clay (SBC)-based geopolymer as aggregates, aiming to address pollution from plastic and edible oil industry waste while promoting a transition into circular economy of repurposing waste. The geopolymer mixture paste, containing PP plastic aggregates in different mass ratios (SBC:PP = 1:0.4, 1:0.6, 1:0.8, and 1:1) is oven cured at 60 °C and 80 °C for 8 h followed by 7 days of room temperature curing. Thermal properties of PP-SBC-based geopolymer mortars with varying compositions of PP plastic were assessed using Thermogravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC). The TGA results revealed that the geopolymer's thermal stability within the temperature range of 620 °C–700 °C improved with an increase in PP plastic aggregate content, up to an optimal amount of 1:08 PPSBCG sample ratio of SBC to PP cured at oven temperature of 80 °C has been chosen as the representative sample for further discussion based on analysis result of ATR-FTIR spectroscopy and BET analysis. Beyond this amount, a reverse trend was observed. The DSC analysis revealed that incorporating PP plastic aggregates reduced its thermal stability towards the melting reaction but improved its thermal insulation properties. However, this effect was observed only up to a composition of PP plastic relative to SBC of 0.6, beyond this threshold, a reverse trend was observed. In addition to TGA and DSC, the geopolymer samples were characterized using Attenuated Total Reflectance - Fourier Transform Infrared (ATR-FTIR) spectroscopy and N2 Brunauer-Emmett-Teller (BET) analysis. This study proved that the addition of high heat-resistant PP plastic into the geopolymer system increased the thermal stability of geopolymers, but only up to a certain optimal quantity. Excessive PP plastic resulted in a reverse trend due to significant effect of weakened interfacial bonding between the geopolymer matrix.

Impact of Packaging Materials on the Shelf Life of Enriched Aadun (Maize Meal Snack commonly consumed by the Southwestern region of Nigeria)

Optimum condition at 64.80% maize flour, 20% groundnut paste and 13.20 % palm oil was formulated to produced nutritionally enhanced aadun snack. The snack was stored in the different storage materials namely, sweet prayer plant leaves (control) which is usually used by most locals, low density polyethylene (LDPE), high density polyethylene (HDPE) and food grade plastic container (PC). The initial properties (energy, oxidative and sensory properties) of the enhanced aadun (before storage) were investigated and stored in each of the storage materials. The enhanced aadun samples in each storage material were analysed at two weeks interval for eighteen weeks. The results obtained were analysed statistically to examine the effect of the storage material on the aforementioned properties. The results for energy content decreased significantly (P&gt;0.05) in across all the samples stored. The free fatty acid, acid valve and peroxide value increased significantly (P&lt;0.05) in all the storage materials during the storage period but only the samples stored in PC and HDPE were within the recommended limit of FAO (Food and Agricultural Organization) at the end of the storage period. The sensory quality of the control sample was acceptable up to 12 weeks while samples in other storage materials were still acceptable at the end of the storage period under ambient storage condition.

Correlation of austenite grain size with ε-/α′-martensitic transformation and mechanical properties in a high-manganese damping steel

One of the core studies on low stacking fault energy (SFE) high-manganese steel is to maintain excellent damping capacity while achieving high strength and toughness. The austenite grain size (AGS) in high-Mn steel affects its SFE and even the strength-plasticity and damping capacity of the steel, but the detailed mechanism related to martensitic transformation has not been clarified. In this study, Fe-17Mn high-Mn damping steel is used as the material to obtain austenite grains of different sizes by controlling the cold rolling and annealing processes. By using in-situ tensile testing, damping capacity testing, and various microscopic analytical techniques, the influence of AGS on the thermal/deformation induced martensitic transformation, work hardening behavior, mechanical properties and damping capacity of the steel is mainly studied. The results indicate that the refinement of austenite grain increases the SFE of high-Mn damping steel and reduces the amount of thermal induced ε-martensite (εth) and stacking faults (SFs). The deformation induced martensitic transformations (DIMTs) in high-Mn damping steel during tensile deformation include γ→εD, εth→α′ and εD→α′ transformation. The deformation induced ε-martensitic transformation is more helpful to improve the work hardening rate than deformation induced α′-martensitic transformation. Due to the concentration of strain partitioning at grain boundaries, twin boundaries and phase boundaries, refinement of austenite grain can promote deformation induced ε-martensitic transformation and improve the steel strength. However, excessively small austenite grains can suppress deformation induced α′-martensitic transformation leading to a significant decrease in elongation. Under the synergetic effects of grain refinement strengthening and multiple martensitic transformations, when the average AGS is about 4.0 μm, the steel has high strength and high plasticity, with a tensile strength of 919 MPa, a yield strength of 518 MPa and an elongation of 46.4 %. The product of tensile strength and elongation is up to 42.6 GPa·%. At low or high strain amplitudes, the damping capacity of this steel shows an opposite trend with the refinement of AGS. The damping capacity of the steel gradually increases with grain refinement at low strain amplitudes of 0.01 %–0.065 %, mainly due to the reduction of the content of weak pinning points. At high strain amplitudes of 0.065 %–0.1 %, the damping capacity of the steel gradually decreases for the reduction of damping sources with the refinement of grain size.

Variation in vessel traits of northern red oak (Quercus rubra L.) provenances revealed high phenotypic plasticity to prevailing environmental conditions

Key messageRed oak provenances responded with high plasticity and intra-annual variability in vessel traits to studied climatic conditions, indicating weak signals of local adaptation and providing opportunities for forest management.The climate change-induced increase in frequency and severity of extreme events has revealed a high vulnerability of various major tree species in Europe, stressing the need for selecting climate-resilient species for forest management. In this context, adaptive strategies of northern red oak (Quercus rubra L.) were examined, using wood anatomical data derived from a provenance trial. We investigated the interannual variation in vessel traits of red oak provenances planted at three sites along a precipitation gradient in Germany. We compared the climate sensitivity of German provenances with those from North America to analyze plasticity and to identify signals of local adaptation in vessel traits. The results revealed variations in vessel traits between all sites, pointing to site-specific responses to prevailing environmental conditions. Differences between provenances were prevalent for vessel size-related traits, with site-specific higher values for German provenances at wet sites. Climate signals, which varied between traits, were strongest for vessel density and the relative conductive area. Vessel traits were found to depend both on previous-year conditions as and on spring climate conditions during the onset of vessel formation. The site-specific response in extreme years deviate significantly between drought and frost events. A trade-off between resistance to extremes and vessel diameter could not be demonstrated, and provenances with larger vessel diameters showed higher frost resistance. The observed high plasticity in vessel traits and the site-specific variation to climate influences point to an adjustment in vessel formation to the prevailing environmental conditions.

High-temperature dependence of yield strength and microstructure in Ni54Fe19Ga27 and (Ni54Fe19Ga27)99.7B0.3 alloys

The deformation behavior, yield strength temperature dependence, and plasticity of the high-temperature L21(B2)-phase during compression in the temperature range 773–1173 K for Ni54Fe19Ga27 and (Ni54Fe19Ga27)99.7B0.3 shape memory alloys was determined for the first time. The studied alloys were characterized by high plasticity (over 70 %) and minimum yield strength level (13–65 MPa) at temperatures from 973 to 1173 K. Possible mechanisms of yield strength decrease, plasticity increase, and microstructure formation during the deformation process depending on test temperature and chemical composition are discussed. The possibility of hot rolling of Ni54Fe19Ga27 alloys at elevated temperatures was demonstrated.

Compression and energy absorption of wood-based reinforced 3D Kagome lattice structures

3D Kagome lattice sandwich structure is recognized as the most excellent lattice configuration. However, the preparation method of 3D Kagome is complicated and the raw materials for its preparation are limited to materials with high plasticity. In this study, we developed a wood-based 3D Kagome lattice structure that combines discrete rods into a continuous core using reinforcement. Orthogonal tests, theoretical analysis, and finite element simulations were performed to investigate the correlation between the dimensional parameters, the mechanical properties, and the energy absorption capacity. The damage modes were found to be mainly bending fracture, core shear, and panel rupture, with the use of reinforcement affecting the damage modes. Compressive properties of the 3D Kagome lattice structure are increased by increasing core diameter and inclination degree, decreasing core in-cut diameter, and using high-strength reinforcements. Finite element simulations further confirm that the use of high-strength reinforcements changes the stress distribution of the lattice structure. The 3D Kagome lattice structure with an inclination degree of 65°, a core diameter of 10 mm, a reinforcement wall thickness of 2 mm, and a core in-cut diameter of 2 mm has the optimal compression performance and energy absorption capacity.

Study on the microstructure, recrystallization, and mechanical properties of hot-press sintered (TiC + B4C)/6061Al composites during hot rolling

Hot rolling is a vital secondary processing technique for aluminum matrix composites. To explore the forming mechanism of (TiC+B4C)/6061Al composites during hot rolling, the 6061Al and (TiC+B4C)/6061Al composites were fabricated via vacuum hot-press sintering followed by hot rolling. The results show that reinforcing particles changed the distribution of Si and resulted in the in-situ generation of SiC in hot-rolled (TiC+B4C)/6061Al composites. During hot rolling, reinforcing particles inhibited the elongation and refined the size of Al grains, and contributed to further enhancing the hardness and strength of hot-rolled 6061Al. With the hot rolling reduction rate increasing, the hardness and strength of hot-rolled (TiC+B4C)/6061Al composites improved, and the refinement effect of reinforcing particles intensified. Both reinforcing particles and hot rolling exhibited effects on the recrystallization behavior of 6061Al during hot rolling, primarily through particle induced nucleation mechanism and strain induced grain boundary migration mechanism. Remarkably, the strength achieved by hot-rolled (TiC+B4C)/6061Al composites at a 20% hot rolling reduction rate rivals that of hot-rolled 6061Al at an 80% hot rolling reduction rate, while still preserving high plasticity. Hot-rolled (TiC+B4C)/6061Al composites predominantly exhibited the ductile fracture of aluminum matrix and cleavage fracture of particles, and the ductile fracture characteristics gradually weakened with the hot rolling reduction rate increasing. The dislocation increment strengthening mechanism contributed the most to the strength improvement of hot-rolled (TiC+B4C)/6061Al composites. This study can provide valuable insights into aluminum matrix composites.

Injection molding of post-industrial recycled glass fiber reinforced polyphenylene sulfide (PPS GF40): industrial feasibility and material analysis

Polymer recycling has become increasingly important in recent decades due to economic and environmental benefits. Recycling provides a cost-saving material supply as well as avoids environmental spillage and enables resource conservation. Quantifying the changes in material properties due to recycling is a key aspect in establishing a circular economy, as it allows understanding the impact of using recycled materials on manufacturing and products. To date, research and industry have investigated the use of recycled materials for commodity and engineering polymers. For high performance plastics, this knowledge exists only at the laboratory scale. The present study comprehensively characterizes the properties of virgin and recycled glass fiber reinforced polyphenylene sulfide (PPS GF40) materials. The materials considered are commercially available to industry, and the recyclates have been reclaimed from post-industrial wastes by the material manufacturers. The results show that as the recycled content increases, the tensile strength of PPS GF40 revealed a similar value for a 50 % recyclate or decreases by 21 % for a regranulate due to both macromolecular shortening and fiber scission. In addition, the shrinkage of each material is quantified. Here, shrinkage increases with increasing result of recycled content. Increasing the amount of recycled material in the compound results in lower process forces in injection molding due to higher melt flow indices. With the help of these results, industrial products may be tailored to meet the properties of recyclate-based materials in order to conserve virgin material resources. In addition, material cost saving potentials are identified by economic calculations based on presently available industrial offers. In the light of the presented results, the introduction of recyclate-based PPS GF40 materials into industrial mass production can be assessed on the basis of mechanical and rheological properties as well as material costs. The overall objective of this study is to provide the aforementioned insights to exploit the economic and environmental benefits of polymer recycling on an industrial scale.

Toward the production of bioblends for the automotive sector: Reuse of recycled polyamide 6,6 to prepare super‐tough biopolyethylene

AbstractPlastics reuse is essential for promoting a sustainable future, especially by mitigating environmental impacts. Recycled polyamide 66 (PA66r) was reused for the produce biopolyethylene (BioPE)‐based blends, aiming to obtain a super‐tough material. Initially, a premix of PA66r with maleic anhydride‐grafted ethylene–propylene–diene (EPDM‐MA) was obtained in an internal mixer. Subsequently, the BioPE/PA66r and BioPE/(PA66r/EPDM‐MA) blends were processed in a twin‐screw extruder and injection molded. The rheological, mechanical, thermal, thermomechanical, structural, and morphological properties were investigated. Torque rheometry indicated an increase in the viscosity of the BioPE/(PA66r/EPDM‐MA) blends compared to BioPE/PA66r, which was confirmed by a reduction in the melt flow index (MFI). EPDM‐MA promoted greater stability in BioPE/(PA66r/EPDM‐MA) blends during processing, reducing the degradation rate and molecular weight loss. The BioPE/(PA66r/EPDM‐MA) blend with the 70/(15/15)% composition exhibited super‐tough behavior, with 822.4 J/m impact strength and 233% elongation at break. Scanning electron microscopy indicated a fracture with high plastic deformation, elongated fibrils, and refined particles (0.64 μm), confirming the high toughness. Apparently, a core‐shell morphology was formed, which favored maintaining tensile strength, Shore D hardness, and heat deflection temperature comparable to pure BioPE. The results indicate potential for application in the automotive industry, contributing to reintroducing recycled material into the production chain.

Long-term deformation of rock salt under creep–fatigue stress loading paths: Modeling and prediction

Rock salt, due to its water solubility, low permeability, high plasticity, and damage self-healing ability, is one of the best candidate rock types for underground energy storage. Utilizing salt caves to construct compressed air energy storage (CAES) facilities can effectively enhance the utilization of renewable energy. Due to the need for peak shaving, the surrounding rock of the salt cavern will undergo discontinuous cyclic loading with varying gas injection rates and pressures, namely, alternating creep–fatigue loading. Considering the actual peak-shaving cycle of a CAES plant, long-term creep–fatigue tests of rock salt with different loading cycles and stress levels were conducted. The results indicate that in long-term creep–fatigue tests for rock salt, the lower the loading stress rate is, the greater the deformation of the rock salt. The variation in the stress limit has a greater effect on creep than on fatigue loading and unloading. The deformation rate of rock salt is influenced by alterations in the stress state. Based on the test results, according to the Norton creep model, a new creep–fatigue constitutive model for rock salt was established by defining a state variable that characterizes the level of rock hardening and introducing unloading as well as crack factors. This model can accurately describe the impact of historical loading and unloading processes on the viscoplastic mechanical characteristics of rock salt. The rock salt creep–fatigue test results were used to verify the constitutive model. A comparison of the fitting curve of the different stress loading paths with the test curve reveals good consistency, indicating that the model comprehensively considers the effects of time, load, and state on rock salt creep–fatigue, effectively describing the viscoplastic deformation characteristics of rock salt under different stress paths. These research findings provide important guidance for ensuring the stability of salt caverns used for CAES.

Attenuated total reflection Fourier-transform infrared spectroscopy reveals environment specific phenotypes in clonal Japanese knotweed

BackgroundJapanese knotweed (Reynoutria japonica var. japonica), a problematic invasive species, has a wide geographical distribution. We have previously shown the potential for attenuated total reflection Fourier-transform infrared (ATR-FTIR) spectroscopy and chemometrics to segregate regional differentiation between Japanese knotweed plants. However, the contribution of environment to spectral differences remains unclear. Herein, the response of Japanese knotweed to varied environmental habitats has been studied. Eight unique growth environments were created by manipulation of the red: far-red light ratio (R: FR), water availability, nitrogen, and micronutrients. Their impacts on plant growth, photosynthetic parameters, and ATR-FTIR spectral profiles, were explored using chemometric techniques, including principal component analysis (PCA), linear discriminant analysis, support vector machines (SVM) and partial least squares regression. Key wavenumbers responsible for spectral differences were identified with PCA loadings, and molecular biomarkers were assigned. Partial least squared regression (PLSR) of spectral absorbance and root water potential (RWP) data was used to create a predictive model for RWP.ResultsSpectra from plants grown in different environments were differentiated using ATR-FTIR spectroscopy coupled with SVM. Biomarkers highlighted through PCA loadings corresponded to several molecules, most commonly cell wall carbohydrates, suggesting that these wavenumbers could be consistent indicators of plant stress across species. R: FR most affected the ATR-FTIR spectra of intact dried leaf material. PLSR prediction of root water potential achieved an R2 of 0.8, supporting the potential use of ATR-FTIR spectrometers as sensors for prediction of plant physiological parameters.ConclusionsJapanese knotweed exhibits environmentally induced phenotypes, indicated by measurable differences in their ATR-FTIR spectra. This high environmental plasticity reflected by key biomolecular changes may contribute to its success as an invasive species. Light quality (R: FR) appears critical in defining the growth and spectral response to environment. Cross-species conservation of biomarkers suggest that they could function as indicators of plant-environment interactions including abiotic stress responses and plant health.