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Potent chemical-free approaches are much needed to control multi-drug resistant pathogens such as biofilm-forming Staphylococcus aureus and rice blast fungus Magnaporthe oryzae. Environmentally safe agricultural practices and wound healing scaffolds based on hydrogels have a limitation arising from formulations containing environmentally toxic cross-linkers or photo-initiators. We have developed non-toxic starch hydrogels with uniformly dispersed silver nanoparticles (AgNP) having wide-spectrum antimicrobial activity for biomedical or agricultural applications. AgNPs were synthesized with Emblica officinalis extract, surface functionalized with the nutraceutical chemical groups in the extract as revealed by Fourier transform infrared spectroscopy. Scanning electron microscopy images show uniform dispersion of AgNP (5 ± 2 nm size) in the hydrogel matrix. AgNP-starch hydrogels are observed to have an excellent antifungal activity to M. oryzae with complete growth inhibition for 10 days compared to the control-starch hydrogel without AgNP and agar gel, even in the presence of the favourable growth medium of yeast extract + glucose. Antibacterial activity was also observed for gram-negative bacteria Escherichia coli and gram-positive bacteria S. aureus using diffusion assay with antibiotic mixture, with four-fold enhancement in zone of inhibition area in case of AgNP-starch hydrogels compared to control starch hydrogels, showing good release efficiency. Sustained release of botanical extracts showed promising bacterial growth inhibition. AgNP hydrogel surface-inhibition of bacterial growth for B. subtilis and E. coli persisted for 8–10 h and S. aureus until 6 h. Starch hydrogels have a high storage modulus G′ = ~ 17 kPa, and AgNP-starch hydrogels have a softer matrix with G′ = 3.6 kPa. Both are stable for a wide range of strain frequencies in the linear viscoelastic regime, revealing the potential for a strong, stable printable scaffold for wound healing. In the dried state, the AgNP-starch films show higher yield point and elongation at break compared to nascent cross-linked starch films under uniaxial tensile forces. Although AgNP-starch hydrogels show a nanoporous morphology enabling controlled drug release, there is negligible AgNP release from the hydrogel matrix. [ABSTRACT FROM AUTHOR]

The safety of coated steel belts (CSBs) is crucial for reliable elevator operation, as they are critical components in elevator systems. Magnetic flux leakage (MFL) testing is the preferred non-destructive method for evaluating CSBs due to its high sensitivity. Previous studies overlooked tensile stress's impact on in-service MFL testing of CSBs, potentially resulting in inaccurate defect assessments. This research aims to investigate the impact of tensile stress on the MFL signal of CSBs by developing a theoretical model, conducting finite element simulations, and performing experimental verification. In this paper, the rectangular edge defects are considered as the primary defect type in CSBs, and the applied stress on the CSBs varies from 30 MPa to 160 MPa. Under the above conditions, a linear relationship between MFL signal of CSBs and stress is established based on the simplified Jiles-Atherton model and magnetic dipole model suitable for CSBs. The finite element simulation and experiments further indicate that the MFL signal of CSBs increases linearly with the increasing tensile stress. The primary contributions of this study are establishing an MFL model suitable for CSBs and uncovering the linear relationship between the MFL signal of CSBs and tensile stress. [ABSTRACT FROM AUTHOR]

Exploring novel high-performance low-dimensional thermoelectric nanomaterials has become a major national development strategy. NEDF was used to study the difference in thermoelectric properties of black phosphorus/black arsenic heterojunction under stress of 2%、4%、6% and 8%. The results show that phonon transport is effectively suppressed under tensile strain of 6%, but the effect on the electronic transport of the device is not obvious. Thermoelectric values of heterojunction nanodevices reaches the maximum value of 2.31 under the control of 6% tensile strain near Fermi level. [ABSTRACT FROM AUTHOR]

PC/ABS blends are commonly used for the production of automotive components due to their thermal and mechanical properties. However, changes in process conditions can have a significant impact on their properties and microstructure. Therefore, determining the optimal parameters for the injection molding (IM) process is critical for effective control of the mechanical properties and quality of the injected parts. In this study, the Taguchi method is applied to investigate the relationship between the tensile stress (σ), Young's modulus (E) and IM process of PC/ABS blends. The effects of different molding parameters such as material temperature, injection pressure, holding time and mold temperature were investigated. The optimal injection parameters to achieve higher tensile stress (σ) and Young's modulus (E) were predicted by studying the signal-to-noise ratio (S/N). Thus, the objectives of the Taguchi approach for the IM process are to determine the optimal combination of process parameters and to reduce the quality variations between only a few trials. Two optimal parameter combinations were found yielding very significant mechanical properties (σ, E) of the injected parts. These optimum combinations consist of material temperature of 260 °C, injection pressure ranging between 40 and 50 bar, holding time of 8 s and mold temperature of 60 °C. Experimental results prove that injection pressure and material temperature have the most significant impact on the mechanical properties and the microstructure of PC/ABS blends. These findings may have interesting applications in the automotive industry. [ABSTRACT FROM AUTHOR]

Copyright of Rare Metals is the property of Springer Nature 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.)

RuO2 has been considered as the most likely acidic oxygen evolution reaction (OER) catalyst to replace IrO2, but its performance, especially long‐term stability under harsh acidic conditions, is still unacceptable. Here, we propose a grain boundary (GB) engineering strategy by fabricating the ultrathin porous RuO2 nanosheet with abundant of grain boundaries (GB‐RuO2) as an efficient acid OER catalyst. The involvement of GB induces significant tensile stress and creates an unsaturated coordination environment, effectively optimizing the adsorption of intermediates and stabilizing active site structure during OER process. Notably, the GB‐RuO2 not only exhibits a low overpotential (η10=187 mV) with an ultra‐low Tafel slope (34.5 mV dec−1), but also steadily operates for over 550 h in 0.1 M HClO4. Quasi in situ/operando methods confirm that the improved stability is attributed to GB preventing Ru dissolution and greatly inhibiting the lattice oxygen oxidation mechanism (LOM). A proton exchange membrane water electrolysis (PEMWE) using the GB‐RuO2 catalyst operates a low voltage of 1.669 V at 2 A cm−2 and operates stably for 100 h at 100 mA cm−2. [ABSTRACT FROM AUTHOR]

Structural superlubricity (SSL) refers to a state of ultralow friction and zero wear when two solid surfaces slide against each other. Recent investigations have identified amorphous carbon at the edge of the graphite mesa as the primary source of friction in such SSL systems. Here, the tensile stress of metal thin film is exploited to engineer vertically conductive edge-warping graphite mesas (EWGM). Through this approach, robust SSL performance is realized, demonstrated by sliding an 8 µm side length square EWGM on an atomically smooth Au substrate for 10000 cycles at a constant voltage of 1 mV. In this SSL system, differential friction coefficients lower than 1.5 × 10−4 are achieved, with static contact resistance between EWGM and Au substrate as low as 28 Ω and sliding contact resistance as low as 32 Ω. Moreover, the EWGM exhibits SSL behavior on polished Si wafer substrates. Furthermore, because of the no-edge contact with the substrate during sliding, friction is independent of the sliding speed of the EWGM. This study presents the first successful fabrication of conductive EWGM. Remarkably, in both EWGM-Au and EWGM-Si SSL systems, the measured frictions are more than one order of magnitude lower than those of ordinary self-retracting graphite mesas with no-edge warping, and no wear is observed during extended current-carrying sliding. Overall, these findings establish a solid groundwork for the future realization of macroscale conductive SSL systems. [ABSTRACT FROM AUTHOR]

Maintaining the geometrical stability of hot filament is a challenge in chemical vapor deposition (CVD) over a larger area since deformation varies the distance between the filament and the substrate and, consequently, destroys the uniformity of diamond deposition. Herein, Ta filament is straightened with a tensile stress ranging from 4.40 to 11 MPa to suppress deformation, and the stability during the CVD process of diamond film is evaluated. Scanning electron microscopy and energy dispersive X‐ray are further utilized to investigate the morphological and structural evolutions of Ta filament. Results show that straightened Ta filament maintains geometrical stability without any visible deformation or breakage and uniform deposition of diamond film is obtained through Ta filament undergone a transformation from Ta to Ta2C and then to TaC. At high deposition pressure (7 kPa) or a low concentration of methane (1%), the straightened Ta filament goes through a moderate transformation, which implies the cracks caused by rough transformation can be avoided, thus prolonging the lifetime of straightened Ta filament. These works provide significant guidelines for the large‐scale manufacture of diamond deposition. [ABSTRACT FROM AUTHOR]

Osteoblasts are mechanosensitive cells. Tensile stress with different conditions, including loading time, frequency, magnitude, etc. would cause varied responses in osteoblasts. However, it was not clarified that the effect of the loading types on the osteoblasts. In this study, we focused on the effect of varied tensile stress types on osteoblasts, including isotropic stretch, biaxial stretch, and uniaxial stretch with the negative ratio of transverse strain to axial strain (NR) −1, 0, and 0.2 respectively. Cell proliferation was determined to be most efficient when stimulated by 6% strain at a frequency of 1 Hz and a negative value of 0 for 1 h/day. The varied strain resulted in a thickening of the F-actin cytoskeleton and a thinning of the nucleus. Nuclear flattening caused Yes-associated protein (YAP) to be transported to the nucleus. It was suggested that the influence of loading types on the mechanobiology responses must be noticed. The mechanism of cell mechanical sensitivity under varied loading types was explored, which would provide good suggestions for designing microstructures to control deformation patterns in bone tissue engineering. [ABSTRACT FROM AUTHOR]

Osteoblasts are mechanosensitive cells. Tensile stress with different conditions, including loading time, frequency, magnitude, etc. would cause varied responses in osteoblasts. However, it was not clarified that the effect of the loading types on the osteoblasts. In this study, we focused on the effect of varied tensile stress types on osteoblasts, including isotropic stretch, biaxial stretch, and uniaxial stretch with the negative ratio of transverse strain to axial strain (NR) −1, 0, and 0.2 respectively. Cell proliferation was determined to be most efficient when stimulated by 6% strain at a frequency of 1 Hz and a negative value of 0 for 1 h/day. The varied strain resulted in a thickening of the F-actin cytoskeleton and a thinning of the nucleus. Nuclear flattening caused Yes-associated protein (YAP) to be transported to the nucleus. It was suggested that the influence of loading types on the mechanobiology responses must be noticed. The mechanism of cell mechanical sensitivity under varied loading types was explored, which would provide good suggestions for designing microstructures to control deformation patterns in bone tissue engineering.

Fretting wear is one of the main degradation mechanisms produced in steel wire and it is widely used for the lifting and handling of equipments. The main objective of the present work is to analyse the mechanical properties of the fretting and non-fretting wire. Statics tensile tests were performed on non-fretting wire and pre-damaged artificially fretting wire subsequently, after that tensile stress (σT), tensile strain (εT), and breaking load (BL) were measured for both wires and their basic mechanical properties were compared. For the analysis wire diameter values varies from 7 mm to 9 mm and artificially pre-damaged wire having reduced diameters varies from 5.8 mm to 8.1 mm were used. From these tests the basic mechanical properties values of maximum tensile stress, tensile strain, modulus of elasticity (E), breaking load (BL) 1610 N/mm², 12.08%, 78854.3 Mpa and 56.73 KN respectively were obtained, for pre-damaged artificially fretting wire. On the other hand, for the non-fretting wire, the values of maximum tensile stress, tensile strain, modulus of elasticity, and breaking load have been obtained as 1171.5 MPa, 16.40 %, 63289.4 MPa and 58.7 KN respectively. [ABSTRACT FROM AUTHOR]

Copyright of China Pulp & Paper is the property of China Pulp & Paper Magazines Publisher 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 electronic states of fullerene structures are modulated by external environments, such as magnetic fields, electric fields, and stress, which exhibit unique physical properties. Compression, i.e., the application of compressive stress to fullerene structures, plays an important role in modulating the optoelectronic properties of fullerene materials. Herein, we comprehensively investigate the stability, band structures, Bloch wave functions, and optical responses of two-dimensional quasi-tetragonal phase C60 (qTP C60) and quasi-hexagonal phase C60 (qHP C60) under external stress. The findings reveal that qTP C60 and qHP C60 can be stabilized within a certain range based on the regulation of external stress. This kind of stress can considerably alter the band structures of qTP C60 and qHP C60, thereby changing the positions of the highest occupied and lowest unoccupied molecular orbitals. The analysis of Bloch wave functions can help visualize the electronic density distribution of qTP C60 and qHP C60 structures, indicating a considerable influence of stress on the electronic state distribution of the system. This influence results in changes in the band structure, thus affecting the electronic distribution state and optical response. Furthermore, qTP C60 and qHP C60 exhibit surface plasmon effects within a specific wavelength range, suggesting their potential applications in optoelectronic devices. [ABSTRACT FROM AUTHOR]

The efforts made all over the world towards the fact of decreasing the environmental pollution have been enormously demanding now a days. Therefore the increase in caution towards a sustainable environment has restricted the use of materials which may have huge impact towards environment pollution. The geosynthetic is a cost-effective and corrosive resistant material which can be used in the most exposed conditions to mitigate the anticipated excessive settlement in case of soft soil. The present study investigated the behaviour of a geocomposite material in a layered soil system. Three types of geocomposite were manufactured by changing the tensile stiffness of the components viz. GCBX-40, GC-BX-60, and GC-BX80. The basic configuration of every geocomposite was same and was made by sandwiching a geotextile layer in between the two geogrid layers which have significantly improved the surface frictional resistance due to the increase in the surface cover ratio and also the improvement in the interlocking effect on the soil grains due to the geogrid layers on both sides. The various layouts of geocomposite were introduced in this study besides the general planar layout and it was found that the confinement effect was increased with in the soil layers. Therefore, the cohesion (c) between the soil grains and the frictional angle (ϕ) was modified due the increased confinement which not only improved the bearing capacity factor but the settlement reductions factor was also improved. The results revealed that the load carrying capacity was improved from 33.8 to 40.59% by using different types of geocomposite. [ABSTRACT FROM AUTHOR]

Stainless steel (SS) is widely used in many fields including aeronautics, automobiles, marine and mechanical industries due to its outstanding feature such as good corrosion resistance and hardness. However, changes in material properties under stress, particularly changes in Young's modulus, result in the formation of cracks, a reduction in load-bearing capacity, and fatigue damage. So, the structural integrity needs to be evaluated based on a precise measurement of mechanical properties. In this study, Stainless Steel 304 (SS-304) is used as the base material and various tensile stresses are applied ranging from 0 MPa to 100 MPa with increment of 10 MPa in each step. Nondestructive Laser Ultrasound Technique (LUT) has been used to characterize the elastic modulus under various tensile stresses. An inverse program was developed based on the Particle Swarm Optimization (PSO) algorithms to determine material properties. Nonlinear Gauss fitting method was proposed and established the fitting equation and nonlinear curve for Young's modulus and residual stress. The outcome of this research shows that when tensile stress is applied, the mechanical properties decrease by shifting the dispersion curve and also it is evident that the dispersion curves move toward the high-frequency-thickness while increasing the tensile stress. When the tensile stress was increased from 0 MPa to 100 MPa, the value of Young's modulus decreased from 201.7 GPa to 193.5 GPa. Especially, the predominant changes were observed during 30–100 MPa. This observation displays the bonding strength and binding energy between the atomics. Further, the proposed nonlinear Gauss fitting substantiated the experimental values and confirmed that the thickness accuracy is close to the inversion values, with an average difference of 4.32%. This research suggests a potential nondestructive method to determine the residual stress of a material by calculating the changes in the elastic modulus. [ABSTRACT FROM AUTHOR]

We investigate how a highly elliptical and mechanically rigid clast embedded in an infinite rock mass respond to the far-field stresses. The numerical analysis is carried out on elliptical clasts with aspect ratios ranging from 13.5 to 58.5, oriented at a right angle to the maximum far-field stress. A 2D plane strain model has been adopted to decipher the states of stress inside elliptical clasts. We argue that the tensile stress within the clasts gets enhanced and develops systematic mode-I (tensile) fractures within it as the far-field stress increases. We conclude that the intra-clast tensile stress decreases with increasing clast ellipticity, i.e., tensile fractures develop more easily within clasts with higher aspect ratios (~>20) while a higher far field tensile stress is required to fracture clasts with lower aspect ratios. We also interpret that stress enhancement is independent of the clast area and inter-focii distance of the clast, whilst the aspect ratio of the clast is found to be crucial for the development of tensile fractures within the elliptical clast for a constant material property. [ABSTRACT FROM AUTHOR]

This paper presents the results of inspecting tensile stress-loaded GFRP (glass fiber-reinforced polymer) samples using the Magnetic Recording Method (MRM). The MRM can be utilized solely to examine ferromagnetic materials. The modification was proposed in order to examine nonmagnetic composites. Ferromagnetic strips made of low-carbon steel DC01 were bonded to the surface using an adhesive composed of epoxy resin with the addition of triethylenetetramine. The modified method's feasibility was tested on six samples made of GFRP. The research procedure consisted of three steps. In the first step, a metal strip is glued at the top surface of each sample, and an array of 100 cylindrical permanent magnets is used to record a sinusoidal magnetic pattern on the strip. The initial residual magnetization is measured in the second step, and the samples are subjected to static stress. In the third step, the residual magnetization is measured one more time. Ultimately, the measurement results from the second and third steps are compared. Generally, the applied stress causes changes in the amplitude and frequency of the sinusoidal magnetization pattern. In the case of GFRP, the frequency changes have not been used for evaluation due to minimal variations. The statistical parameters (mean, median, max, and mode) of the RMS (root mean square) value of the sinusoidal pattern were calculated and analyzed. The analysis demonstrates that the modified method is suitable for providing unequivocal and exact information on the load applied to a nonmagnetic composite material. For the presented results, the applied load can be assessed unambiguously for the samples elongated up to 0.6%. [ABSTRACT FROM AUTHOR]

BACKGROUND: There is a lack of consensus concerning the coracoid graft length in the modified Bristow procedure. OBJECTIVE: We attempted to determine the optimal graft length using the three-dimensional finite element method. METHODS: In a shoulder model with a 25% anterior glenoid defect, a coracoid graft of varying lengths (5, 10, 15, and 20 mm) was fixed using a half-threaded screw. First, a compressive load of 500 N was applied to the screw head to determine the graft failure load during screw tightening. Next, a tensile load (200 N) was applied to the graft to determine the failure load due to biceps muscle traction. RESULTS: In the screw compression, the failure loads in the 5-, 10-, 15-, and 20-mm models were 252, 370, 377, and 331 N, respectively. In the tensile load applied to the coracoid graft, the failure load exceeded 200 N for both the 5- and 10-mm models. CONCLUSION: The 5-mm graft had a high risk of fracture during intraoperative screw tightening. As for the biceps muscle traction, the 5- and 10-mm-grafts had a lower failure risk than the 15- and 20-mm-grafts. Therefore, we believe that the optimal length of the coracoid graft is 10 mm in the modified Bristow procedure. [ABSTRACT FROM AUTHOR]

The effect of laser irradiation and tensile stress on the microstructure and soft magnetic properties of the FeSiBNbCu nanocrystalline alloy prepared using a continuous laser has been investigated. The experimental results indicate that a decreased laser scanning speed provides more thermal energy to induce nanocrystals and encourage grain growth. When the scanning speed is excessively high, the crystallization process will cease due to a lack of energy to drive diffusion phase transitions. Nevertheless, the introduction of tensile stress could significantly promote crystallization in FeSiBNbCu alloy samples irradiated at these high laser scanning speeds. This phenomenon can be attributed to the augmentation of compressive thermal stress at the interface between the laser-treated track and the untreated region. This heightened compressive stress promotes the diffusivity of atoms, and, as a result, the transformation from amorphous to crystalline states can be enhanced. As the applied tensile stress increases, both grain size and crystalline volume fraction exhibit a proportional augmentation. Consequently, these changes manifest in the soft magnetic properties. The crystalline volume fraction can reach 62%, and the coercivity is 2.9 A/m at the optimized scanning speed; these values correspond to 54% and 3.3 A/m under specific tensile stress loading. [ABSTRACT FROM AUTHOR]

Flexible transparent electrodes are integral to the advancement of flexible optoelectronic devices such as flexible displays and solar cells. However, indium tin oxide (ITO), a traditional material used in transparent electrodes, exhibits a significant increase in resistance under mechanical stress, which limits the long-term stability of flexible devices. Here, we prepare various types of silver nanowire (AgNW)-based transparent electrodes and investigate their stability in terms of electrical resistance and optical transmittance under compressive and tensile stresses. Under compressive stress, ITO on a polyethylene terephthalate (PET) substrate exhibits a significantly high electrical resistance of >3000 Ω after 1000 stress cycles, while the AgNW-coated electrode on a PET film exhibits a relatively smaller resistance of <1200 Ω. The AgNW-embedded electrode in a UV-curable polymer matrix (NOA63 or NOA71) exhibits an even lower electrical resistance of <450 Ω because AgNWs can easily maintain their network. A similar trend is observed under tensile stress. The AgNW-embedded electrode shows the highest resistance stability, whereas the ITO on the PET substrate shows the poorest stability. The optical transmittance is comparable regardless of the type of stress or electrode used. This superior stability of the AgNW-based electrodes, realized by integrating it with a polymer matrix, is promising for the development of durable and high-performance flexible optoelectronic devices. [ABSTRACT FROM AUTHOR]

The present work involves the investigation of the synergistic effects of gamma irradiation, tensile stress and absorbed moisture on the radiolysis behaviors of silicone foams by experiments and theoretical simulations. For both the pristine and dehydrated samples, the permanent tensile set increases with the initial tensile strain. Further analysis uncovers that the dehydrated samples exhibit greater permanent tensile sets, lower further elongation and higher Young's modulus than the counterparts of the pristine samples with the same initial tensile strain and gamma dose, verifying the vital synergistic effects on crosslinking network and aggregation structures caused by moisture and gamma radiation. The synergistic effects unveiled by reactive molecular dynamics at the atomic scale are due to the moisture-induced neutralization and stabilization of the macromolecular radicals. The steric hindrance of moisture located at the interface of silica and polymer chains also conduces to the observed synergistic effects due to the inhibited crosslinking reactions. [ABSTRACT FROM AUTHOR]

Abstract Background Integrins are closely related to mechanical conduction and play a crucial role in the osteogenesis of human mesenchymal stem cells. Here we wondered whether tensile stress could influence cell differentiation through integrin αVβ3. Methods We inhibited the function of integrin αVβ3 of human mesenchymal stem cells by treating with c(RGDyk). Using cytochalasin D and verteporfin to inhibit polymerization of microfilament and function of nuclear Yes-associated protein (YAP), respectively. For each application, mesenchymal stem cells were loaded by cyclic tensile stress of 10% at 0.5 Hz for 2 h daily. Mesenchymal stem cells were harvested on day 7 post-treatment. Western blotting and quantitative RT-PCR were used to detect the expression of alkaline phosphatase (ALP), RUNX2, β-actin, integrin αVβ3, talin-1, vinculin, FAK, and nuclear YAP. Immunofluorescence staining detected vinculin, actin filaments, and YAP nuclear localization. Results Cyclic tensile stress could increase the expression of ALP and RUNX2. Inhibition of integrin αVβ3 activation led to rearrangement of actin filaments and downregulated the expression of ALP, RUNX2 and promoted YAP nuclear localization. When microfilament polymerization was inhibited, ALP, RUNX2, and nuclear YAP nuclear localization decreased. Inhibition of YAP nuclear localization could reduce the expression of ALP and RUNX2. Conclusions Cyclic tensile stress promotes early osteogenesis of human mesenchymal stem cells via the integrin αVβ3-actin filaments axis. YAP nuclear localization participates in this process of human mesenchymal stem cells. Video Abstract

Rock fracturing is one of the main processes in the modern mining, mineral recovery, and energy industry, which is associated with the numerous environmentally harmful influences. Environmentally friendly alternative to conventional fracturing methods is non-explosive technology, which based on using of soundless chemical demolition agents (SCDA). In this study, method of directional fracturing, which based on creating tensile stress concentrators on the hole surface in the required location, was proposed. Considering the influences of additional installation in the borehole of stress concentration cartridge on stress field nearby the hole, a case study of the effectiveness of proposed rock fracturing method was performed in this paper. A numerical simulation was used to study the stress distribution around the borehole with SCDA in different rock types. It was found that cartridge installation leads to the occurrence of the tensile stress concentrations only near to the gap of the cartridge. The value of tensile stress concentration in the proposed rock fracturing method significantly depends on a cartridge gap distance. An increase in the gap distance leads to a decrease in the stress concentration factor. For granite, sandstone and mudstone, relationships of stress concentration factor to cartridge gap distance that was divided on hole diameter were obtained. The equation for calculating of the hole spacing for the directional fracturing method was proposed. The results of the study are confirmed by experiments in-situ on the directional fracturing of rocks in a quarry and in a coal mine.

Background: Integrins are closely related to mechanical conduction and play a crucial role in the osteogenesis of human mesenchymal stem cells. Here we wondered whether tensile stress could influence cell differentiation through integrin αVβ3. Methods: We inhibited the function of integrin αVβ3 of human mesenchymal stem cells by treating with c(RGDyk). Using cytochalasin D and verteporfin to inhibit polymerization of microfilament and function of nuclear Yes-associated protein (YAP), respectively. For each application, mesenchymal stem cells were loaded by cyclic tensile stress of 10% at 0.5 Hz for 2 h daily. Mesenchymal stem cells were harvested on day 7 post-treatment. Western blotting and quantitative RT-PCR were used to detect the expression of alkaline phosphatase (ALP), RUNX2, β-actin, integrin αVβ3, talin-1, vinculin, FAK, and nuclear YAP. Immunofluorescence staining detected vinculin, actin filaments, and YAP nuclear localization. Results: Cyclic tensile stress could increase the expression of ALP and RUNX2. Inhibition of integrin αVβ3 activation led to rearrangement of actin filaments and downregulated the expression of ALP, RUNX2 and promoted YAP nuclear localization. When microfilament polymerization was inhibited, ALP, RUNX2, and nuclear YAP nuclear localization decreased. Inhibition of YAP nuclear localization could reduce the expression of ALP and RUNX2. Conclusions: Cyclic tensile stress promotes early osteogenesis of human mesenchymal stem cells via the integrin αVβ3-actin filaments axis. YAP nuclear localization participates in this process of human mesenchymal stem cells. 7pqm7m_g_KeHaQ8nD7WfNi Video Abstract [ABSTRACT FROM AUTHOR]

In 2018, the European Commission adopted the European Strategy for Plastics in a Circular Economy, which outlines key actions to reduce the negative impact of plastic pollution. The strategy aims to expand plastic recycling capacity and increase the proportion of recycled materials in plastic products and packaging. Using recycled plastic can save 50–60% energy compared to virgin plastic. Recycled PET can be used in the production of A-PET films, which are predominantly used in thermo-vacuum forming for food packaging. Storage conditions can influence the mechanical properties of polymer materials. This work presents changes in the mechanical properties of A-PET films after UV irradiation. An experimental investigation of the UV aging of A-PET films was conducted in a UV aging chamber. The specimens were exposed to a UV radiation dose rate of 2.45 W/m2 for 1, 2, 4, 8, 16, 24, 32, and 40 h. UV measurements were also taken on a sunny day to compare the acceleration of UV irradiation in the UV aging chamber. Mechanical tensile tests were performed on two different three-layer A-PET films (100% virgin and 50% recycled). The tensile strength and relative elongation of the A-PET films were determined, and the work required to break the film was calculated. The total consumed work was divided into the work needed for elastic and plastic deformations. A study of the UV aging of A-PET films confirmed a significant effect on the films, including a loss of plasticity even after brief exposure to solar irradiance. The results of the puncture impact test further confirmed the deterioration of the mechanical properties of A-PET material due to exposure to UV radiation, with a greater effect observed for the recycled material. [ABSTRACT FROM AUTHOR]

Composite fibers are an essential component of modern concrete structures, providing enhanced mechanical properties and durability. There are different types of fibers commonly used in concrete such as steel, glass, carbon, polypropylene fibers, etc. Composite fibers include a combination of two or more of these fibers. Composite fibers are discussed in detail, along with their properties and benefits. This paper also highlights the effects of composite fibers on the various properties of concrete, such as compressive strength, tensile strength, toughness, and durability. Furthermore, this paper discusses some of the challenges and limitations associated with the use of composite fibers in concrete, including issues related to fiber dispersion, fiber--matrix interactions, and costeffectiveness. Finally, this paper concludes with a discussion of the future directions of research on composite fibers in concrete, focusing on potential advancements in fiber technology, improved manufacturing techniques, and the development of new fiber--matrix systems. Overall, this paper provides a comprehensive overview of the current state of the art in composite fibers in concrete and serves as a valuable resource for researchers and practitioners in the field. [ABSTRACT FROM AUTHOR]

Poly(glycerol sebacate) (PGS) is an excellent scaffold material in tissue engineering due to good biocompatibility and tunable mechanical properties. The degradation properties of PGS have been primarily explored in static phosphate buffer solution or enzyme solution. It is vital to understand how the tensile stress affect the degradation rate. In this study, PGS was synthetized by melt polycondensation and its properties were characterized. Then an in vitro degradation device which could provide different constant tensile stresses was carefully designed and established, and the enzymatic degradation of PGS was tested under 0–150 kPa at 37°C. It was found that holes of PGS surface arranged almost parallel to each other and perpendicular to the direction of tensile stresses at 100 kPa and 150 kPa after 2–4 days degradation. After 8 days degradation, the ultimate tensile strength (UTS) of PGS at 150 kPa was 0.28 MPa and the elastic modulus was 1.11 MPa, while the UTS of PGS was 0.44 MPa and the elastic modulus was 1.63 MPa before degradation, both of them have significant differences. Hence, the tensile stress and degradation time were proportional to the appear time and size of holes, leading to the decrease of mass loss, UTS and elastic modulus. The relationship between stress and PGS degradation rates was quantitatively described through our degradation experiments, providing guidance for suitable PGS applications in the future. [ABSTRACT FROM AUTHOR]

The instability of an incompressible boundary layer on a compliant plate with respect to inviscid perturbations in the limit of high Reynolds numbers is analyzed using triple-deck theory. It is shown that unstable inviscid perturbations can exist only if the inertia and/or damping of the plate are taken into account. A twofold role of damping is revealed: it suppresses instability under certain conditions, while leading to its generation under other conditions. [ABSTRACT FROM AUTHOR]

The aim of the article is to study the influence of the water content in the epoxy resin on the mechanical properties of the result laminate. The mechanism of resin contamination by air humidity is considered. The NIR spectrometry method was chosen to monitor the water content in the resin. The mechanical strength parameters of the laminate created from clean and water-contaminated resin were determined on the base of simulation and real tensile tests.

This article presents the stresses at the center of a Brazilian disk (BD) for transversely isotropic rocks. It is shown that the solution of stresses at the center of an anisotropic disk is a function of the disk radius and the magnitude of applied load, as well as the material orientation with respect to the load axis and two dimensionless ratios with specific physical meanings and limitations. These two dimensionless parameters are the ratios of Young’s modulus and apparent shear modulus, although the ratio of apparent shear modulus will be eliminated if the Saint-Venant assumption is considered. Considerable finite element simulations are carried out to find the stresses at the disk center concerning the material orientation and the two dimensionless parameters. Also, an approximate formula obtained from analytical results, previously proposed in the literature for solving the tensile and compressive stresses at the disk center, is re-written and simplified based on these new definitions. The results of the approximate formula fitted to the analytical results are compared to those obtained from numerical solutions, suggesting a good agreement between the numerical and analytical methods. An approximate equation for the shear stress at the disk center is also formulated based on the numerical results. Finally, the influence of the assumptions for simplification of the proposed formula for the tensile, compressive, and shear stresses at the disk center is discussed, and simple and practical equations are proposed as estimations for the stresses at the center of the BD specimen for low to moderate anisotropic rocks. For highly anisotropic rocks, the reference plots can be used for more accuracy.

This paper introduces the basic theory behind magnetoelastic sensors which are based on the change of magnetic properties (permeability) due to mechanical stress (Villari effect). A well-known magnetoelastic sensor, the Pressductor, is described. A simulation model of a sensor is created, described, and evaluated by computing the static transfer characteristic of RMS secondary coil voltage change due to tensile stress. A real sensor is then manufactured from a polycrystalline transformer sheet and experimentally tested by using a tensile load created by water weight. The simulation and experiment show similar behavior but are not completely identical which is most likely since some material properties were taken from literature rather than from experimental measurements, like the magnetostriction coefficient and initial magnetic susceptibility.

A recently introduced bendable concrete having hundred times greater strain capacity provides promising results in repair of engineering structures, known as strain hardening cementitious composites (SHHCs). The current research creates new empirical prediction models to assess the mechanical properties of strain-hardening cementitious composites (SHCCs) i.e., compressive strength (CS), first crack tensile stress (TS), and first crack flexural stress (FS), using gene expression programming (GEP). Wide-ranging records were considered with twelve variables i.e., cement percentage by weight (C%), fine aggregate percentage by weight (Fagg%), fly-ash percentage by weight (FA%), Water-to-binder ratio (W/B), super-plasticizer percentage by weight (SP%), fiber amount percentage by weight (Fib%), length to diameter ratio (L/D), fiber tensile strength (FTS), fiber elastic modulus (FEM), environment temperature (ET), and curing time (CT). The performance of the models was deduced using correlation coefficient (R) and slope of regression line. The established models were also assessed using relative root mean square error (RRMSE), Mean absolute error (MAE), Root squared error (RSE), root mean square error (RMSE), objective function (OBF), performance index (PI) and Nash-Sutcliffe efficiency (NSE). The resulting mathematical GP-based equations are easy to understand and are consistent disclosing the originality of GEP model with R in the testing phase equals to 0.8623, 0.9269, and 0.8645 for CS, TS and FS respectively. The PI and OBF are both less than 0.2 and are in line with the literature, showing that the models are free from overfitting. Consequently, all proposed models have high generalization with less error measures. The sensitivity analysis showed that C%, Fagg%, and ET are the most significant variables for all three models developed with sensitiveness index higher than 10 %. The result of the research can assist researchers, practitioners, and designers to assess SHCC and will lead to sustainable, faster, and safer construction from environment-friendly waste management point of view.

This paper presents the findings of the numerical studies performed on a two-tiered reinforced fly ash wall. Fly ash was used as backfill material and jute geotextile was used as reinforcement as well as facing material. Wrap-around facing was used in which the jute geotextile was folded at the face. Three-dimensional models of fly ash walls showing offsets at varying distances between the two tiers and the length of reinforcement were prepared. The horizontal displacement on the wall face, tensile forces on reinforcement, and settlement behavior of the backfill wall were analyzed. Further, the wall model was scaled 10 times to generate large-scale fly ash models to understand the behavior of a life-size reinforced fly ash tiered wall. The displacement in the horizontal direction at the face of the wall reduced with the increase in length of the reinforcement and the distance between the tiers. The influence of the offset distance between the tiers on the tensile forces acting on the reinforcement was also investigated. The critical distance between the offsets was identified as 0.6 times the lower tier height. The tiered wall in the present study showed significant reduction in mobilized tensile force in the reinforcements especially at the lower tier as compared with a single (without tier) reinforced fly ash wall of the same height. The maximum tensile force for a single wall was observed to be 1.25 times and 5.35 times the two-tiered wall with D/L = 0.6 for upper and lower tiers, respectively, where D = distance of the offsets between the two tiers and L = height of lower tier. The safety factors were determined by using strength reduction factors. The factor of safety increased with an increase in the offset distance. Similar trends were observed for large-scale models. Jute geotextile reinforced fly ash models were analyzed using finite-element analysis. The results are relevant for the construction of fly ash wall reinforced with jute geotextile. The distance between the offsets was varied and a critical distance between the offsets was identified as 0.6L. The practical implication of the study is a reduced offset distance. The previous studies have identified a larger value of such distance. The current ratio for offset distance should be considered while designing the reinforced fly ash wall in tiered configuration. A change in position as well as value of tensile force acting on reinforcement was observed with the change in the distance between the offsets, thereby changing the location of failure plane. This should be taken in to account while designing the reinforcement for the wall. [ABSTRACT FROM AUTHOR]

Due to new environmental regulations, hexavalent chromium electrolytes can no longer be used for thick, hard chromium plating. In response to this industrial and environmental challenge, trivalent chromium electrolyte plating has been developed. In this paper, we propose a study of the adhesion of CrIII coatings based on the implementation of numerical models in comparison with an identified experimental scenario. The aim is to dissociate the influence of coating and substrate behaviours from the adhesion work by describing the intrinsic damage of the chromium layer and the coating–substrate interface. Two types of cracking were studied: transverse cracking and delamination. For the former, the crack density was higher for CrIII than for CrVI and increased with deformation and coating thickness. Microtensile tests with scanning electron microscopy (SEM) observations allowed us to highlight the cracking process in the coating (transverse cracking) and at the coating–substrate interface (delamination). The numerical simulation of the test allowed us to estimate a damage-initiation threshold normal stress of 1900 MPa, which occurred at an average applied strain of 2.5%. Delamination of the coating was complete at an average strain of 13.6% and an interfacial normal stress of 2600 MPa. [ABSTRACT FROM AUTHOR]

Polylactide (PLA) has become a popular alternative for petroleum-based plastics to reduce environmental pollution. The broader application of PLA is hampered by its brittle nature and incompatibility with the reinforcement phase. The aim of our work was to improve the ductility and compatibility of PLA composite film and investigate the mechanism by which nanocellulose enhances PLA polymer. Here, we present a robust PLA/nanocellulose hybrid film. Two different allomorphic cellulose nanocrystals (CNC-I and CNC-III) and their acetylated products (ACNC-I and ACNC-III) were used to realize better compatibility and mechanical performance in a hydrophobic PLA matrix. The tensile stress of the composite films with 3% ACNC-I and ACNC-III increased by 41.55% and 27.22% compared to pure PLA film, respectively. Compared to the CNC-I or CNC-III enhanced PLA composite films, the tensile stress of the films increased by 45.05% with 1% ACNC-I and 56.15% with 1% ACNC-III. In addition, PLA composite films with ACNCs showed better ductility and compatibility because the composite fracture gradually transitioned to a ductile fracture during the stretching process. As a result, ACNC-I and ACNC-III were found to be excellent reinforcing agents for the enhancement of the properties of polylactide composite film, and the replacement some petrochemical plastics with PLA composites would be very promising in actual life. [ABSTRACT FROM AUTHOR]

To determine the exact distribution of tensile stress in a cold rolled strip, tensile stress evolution caused by lateral uneven velocity distribution outside the deformation zone of the strip is examined. The finite difference method is employed to solve the problem. Different factors, including the strip width and the form and amplitude of the initial stress distribution on the stress evolution, are analyzed. On the one hand, to improve the calculation speed, a "Gaussian" curve is proposed to fit the results calculated by the finite difference method. Simulation results show that the stress evolution calculated by the fitting equation is in good agreement with that obtained by the finite difference method. On the other hand, to verify the exactness of the model, an experiment is conducted, and the comparison between the calculated results and experimental values is discussed. [ABSTRACT FROM AUTHOR]

Components of civil buildings are frequently made of low-alloyed steel, which can suffer from corrosion damage. This damage reduces their bearing capacity and/or redistributes the load to neighboring regions with the potential risk of their collapse. For this reason, this study deals with the non-destructive monitoring of bodies made of these steels based on Barkhausen noise emission. The superimposing contribution of corrosion extent and exerted tensile load is investigated on samples of variable yield strength in the range from 235 to 1100 MPa. It is found that the presence of a corroded layer attenuates Barkhausen noise and makes the body harder from a magnetic point of view. The reduced effective thickness of the samples as a result of corrosion damage increases the true stress. Barkhausen noise grows along with the tensile stress in the direction of exerted stress at the expense of decreasing Barkhausen noise in the perpendicular direction. The evolution of Barkhausen noise versus tensile stress is mostly shifted to the lower values of Barkhausen noise, along with the increasing degree of corrosion damage. The evolution of Barkhausen noise versus tensile stress is also affected by the initial microstructure and the corresponding yield strength of the low-alloyed steel. Corrosion attack results in the growth of FWHM, which is compensated by the decreasing evolution along with the tensile stresses. The effective values drop down with the higher extent of corrosion damage. However, the response with respect to the tensile stress is asymmetric in RD and TD due to the realignment of DWs into RD. Finally, PP tends to increase with the corrosion attack as well as the tensile stress and this parameter only exhibits the systematic behavior in RD as well as TD. On the other hand, MBN-extracted parameters as well as their combination provide no exclusive values on which the pure contribution of corrosion and tensile stress can be distinguished. [ABSTRACT FROM AUTHOR]

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The Superconducting Conductor Testing Facility, which is developed to evaluate the reliability of engineering technology and safe operation in fusion reactor operation environment, is under engineering design by ASIPP. In case of an emergency shut-down like in succession of a quench, the voltage across the coil may rise to about 2.5 kV. The facility has to be reliably insulated. In this study, we present the preliminary design of the insulation system of the Superconducting Conductor Testing Facility, which includes turn and ground insulation. Since the magnet of the facility adopts the manufacturing process of “Wind&React”, the turn insulation material should withstand a heat treatment with temperature up to 650 °C. The insulation system is composed of S-glass fiber reinforced tape and vacuum-pressure impregnated in a DGEBF epoxy system. The mechanical properties are being subjected to investigations with respect to the design requirements and operating conditions. The test results are analyzed to verify the feasibility of the insulation system design. [ABSTRACT FROM AUTHOR]

Optical fibres with diameters at micro- or sub-micrometre scale are widely adopted as a convenient tool for studying light–matter interactions. To prepare such devices, two elements are indispensable: a heat source and a pulling force. In this paper, we report a novel fibre-tapering technique in which micro-sized plasmonic heaters and elaborately deformed optical fibres are compactly combined, free of flame and bulky pulling elements. Using this technique, micro-nano fibres with abrupt taper and ultra-short transition regions were successfully fabricated, which would otherwise be a challenge for traditional techniques. The compactness of the proposed system enabled it to be further transferred to a scanning electron microscope for in-situ monitoring of the tapering process. The essential dynamics of “heat and pull” was directly visualised with nanometre precision in real time and theoretically interpreted, thereby establishing an example for future in-situ observations of micro and nanoscale light-matter interactions.