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In this study, the wall shear stress in the channel flow of polyacrylamide polymers was investigated through electrochemical experiments, and the effects of the polymer concentration were evaluated at different Reynolds numbers. The objective was to explore the relationship between the changes in the drag reduction and near-wall turbulence structure induced by the polymer. The experiments were conducted using polymer concentrations of 0, 20, 50, 100, and 150 ppm, and a drag reduction of approximately 23% was achieved at a bulk Reynolds number of R e b = 18 750. In the electrochemical method, the working electrode was arranged spanwise, and simultaneous measurements were performed for eight electrodes to discuss the scale of the near-wall low-speed streaks and burst events. A comprehensive analysis of the correlation of the wall shear stress in the streamwise direction and the cross-spectrum of two points in the spanwise direction revealed that large streamwise and spanwise scales of near-wall low-speed streaks were generated at high polymer concentrations. Furthermore, the results obtained using the variable interval time averaging technique indicated that polymer incorporation suppressed the wall shear stress fluctuations and weakened both the intensity and frequency of the bursting events. [ABSTRACT FROM AUTHOR]

Water jet propulsion pumps start at special stages such as mooring and sailing, the ship is in shallow water, and the underwater keen clearance (UKC) is relatively small, which is easy to induce underwater suction vortex near the inlet position and cause violent vibration of the pumping unit. The powerful suction effect of the water-jet propulsion pump can draw in debris from the bottom of the riverbed, causing damage to the propulsion pump. This research investigated the suction effect of water jet propulsion pump under different UKC conditions. A flow field analysis method based on the entropy weight theory was constructed to reveal the flow characteristics of the flow field where the underwater suction vortex occurs. The research found that the suction effect on the flow field tends to stabilize under the condition of UKC greater than 2.5D0. After UKC reaches 4.2D0, suction effects essentially cease to create large-scale shear stresses near the riverbed. In addition, this research analyzes the vorticity field using vorticity and net circulation to elucidate the vortex strength within the flow field under different UKC conditions. The probability of generation of underwater suction vortices will be greatly reduced when the UKC is greater than 0.83D0. [ABSTRACT FROM AUTHOR]

Taylor–Couette flow with a high Taylor number and large radius ratio is widely present in fluid machinery, such as the internal clearance flow in a canned motor pump typically. Taylor–Couette flow with radius ratios from 0.934 to 0.977 and Taylor number from 107 to 1010 was investigated by numerical simulations. The results indicated that torque is positively correlated to radius ratio, while dimensionless torque is exponentially related to the Taylor number. Subsequently, the physical characteristics of the flow field were described by extracting statistical quantities such as the average azimuthal velocity profile, velocity fluctuations, and near-wall region analysis at four internal cylinder rotation frequencies and four radius ratios. The results revealed that increasing rotation frequency would increase velocity gradients near the wall, while higher radius ratios would produce more uniform velocity fluctuation distributions. In addition, near-wall profiles showed a constant shear force layer, while the logarithmic layer was affected by rotation frequency and radius ratio. The detailed analysis revealed that as the rotation frequency increased, the flow gradually transitioned to a turbulent state, intensifying the interaction between large and small vortex structures. The rotation speeds of Taylor vortices remained consistent across different radius ratios, with smaller scales and more numerous vortices observed at larger ratios. Smaller radius ratios led to more fine-scale vortex structures near the cylindrical wall, significantly impacting azimuthal velocity fluctuations. Finally, near-wall velocity streaks are presented to demonstrate their periodic nature and the relationship between high-speed and low-speed regions, as well as their interaction with the wall and changes with distance. [ABSTRACT FROM AUTHOR]

Minimizing drag on the cavitator is essential in hydrodynamic research and for improving the performance of objects used in marine environments. This study focuses on optimizing a parabolic cavitator and analyzing the cavities it generates in detail. First, the key factors for optimizing the cavitator were identified using the Taguchi method. Based on these factors, the three-dimensional shape of the cavitator was numerically simulated, and the hydrodynamic forces acting on it were calculated with consideration of cavitation. The optimized cavitator shape was then identified through further analysis using the Taguchi method and was experimentally tested to confirm its real-world performance. Subsequently, the characteristics of artificial cavitation behind the improved cavitator were examined both experimentally and numerically across various ventilation coefficients. The experiments included high-speed imaging and pressure measurements to capture the dynamics of cavity formation and collapse, while numerical simulations were performed using a k-omega shear stress transport turbulence model and a volume of fluid approach to accurately predict the phase interface. The results highlight the importance of the cavitator's incidence angle and the distance from its nose to its base in the optimization process. Moreover, the analysis shows that pressure fluctuations are significantly more intense at the point where the cavity closes than within the cavity itself. Additionally, the findings indicate that the supercavity characteristics generated by this optimized cavitator are 10% better than those produced by other cavitators, contributing to reduced drag and improved hydrodynamic efficiency. [ABSTRACT FROM AUTHOR]

The stability of a rigid particle in yield stress fluids, comprised of soft particle glasses (SPGs), is investigated in shear flow under an applied external force, such as weight, using particle dynamics simulations. Results provide the critical force threshold, in terms of the dynamic yield stress and the flow strength, required to initiate sedimentation of the rigid particle over a wide range of shear rates and volume fractions. The streamlines of the SPGs show local disturbances when the rigid particle settles. The form of these disturbances is consistent with the microdynamics and microstructure response of the neighboring soft particles of the sedimenting rigid particle. Sedimenting particle induces non-affine displacement to the suspensions at low shear rates and high applied forces, while these dynamical events are localized and suppressed at high shear rates. Stability diagrams, which provide the conditions of the sedimentation of the rigid particle, are presented in terms of the applied force and the shear rate. These individual stability diagrams at each volume fraction map onto a universal stability diagram when the external force is scaled by the dynamic yield stress and shear rate with a ratio of the solvent viscosity to the low-frequency modulus of the SPGs. [ABSTRACT FROM AUTHOR]

The novelty of this work is in its prediction of the non-Newtonian behavior of polymeric liquids in the orthogonal superposition of small-amplitude oscillatory shear flow upon steady shear flow. We do so using rotarance theory, namely, by considering only the orientability of the macromolecules in suspension. We arrive at explicit analytical solutions for the complex viscosity as a function of the steady shear rate and of the frequency of the superposed oscillation. Our results explain the canonical laboratory observations of orthogonal superposition: (α) the real part of the complex viscosity as a function of frequency decreases with increasing steady shear rate, (β) the curves of minus the imaginary part as a function of frequency go through a maximum, and (γ) the independence of the steady mean shear stress from the superposed oscillation. We compare our predictions with those of parallel superposition and discover that the further the macromolecular structure from axisymmetric, I 3 / I 1 = 1 , the greater the difference between parallel and superposition. In other words, studying both directions of superposition of either part of the complex viscosity uncovers the most important feature of macromolecular structure, the moment ratio, I 3 / I 1 , and thus, the macromolecular orientability. [ABSTRACT FROM AUTHOR]

We propose sparse regression as an alternative to neural networks for the discovery of parsimonious constitutive models (CMs) from oscillatory shear experiments. Symmetry and frame invariance are strictly imposed by using tensor basis functions to isolate and describe unknown nonlinear terms in the CMs. We generate synthetic experimental data using the Giesekus and Phan-Thien Tanner CMs and consider two different scenarios. In the complete information scenario, we assume that the shear stress, along with the first and second normal stress differences, is measured. This leads to a sparse linear regression problem that can be solved efficiently using l1 regularization. In the partial information scenario, we assume that only shear stress data are available. This leads to a more challenging sparse nonlinear regression problem, for which we propose a greedy two-stage algorithm. In both scenarios, the proposed methods fit and interpolate the training data remarkably well. Predictions of the inferred CMs extrapolate satisfactorily beyond the range of training data for oscillatory shear. They also extrapolate reasonably well to flow conditions like startup of steady and uniaxial extension that are not used in the identification of CMs. We discuss ramifications for experimental design, potential algorithmic improvements, and implications of the non-uniqueness of CMs inferred from partial information. [ABSTRACT FROM AUTHOR]

In the context of eccentric micro-scale Taylor–Couette flow, variations in localized flow scales result in a non-uniform fluid–solid interface slip state, distinct from the typically studied uniform slip velocity distribution. This study introduces a boundary condition definition method aimed at characterizing partial slip states, complemented by a coupled iterative analysis system tailored to address this complexity. Key contributions include the development of a method for calculating the limiting shear stress, which considers local velocity gradients and pressures. Validation demonstrates that the locally derived slip state aligns more closely with Knudsen number distributions of local flow scales compared to traditional uniform slip models, and exhibits greater consistency with experimentally measured pressure distributions. Additionally, the study reveals that eccentric Taylor–Couette flow, characterized by significant variations in local flow scales and strong self-induced pressure effects, leads to complex distributions of local pressure, velocity gradients, and differences in local slip velocities. Specifically, the non-uniform distribution of local pressure gradients due to eccentricity results in partial slip occurring predominantly on the rotor in regions with positive pressure gradients, and on the stator in regions with negative pressure gradients. Furthermore, the variation in gap height exerts a greater influence on local slip compared to rotational speed and eccentricity ratio. Under certain conditions influenced by pressure gradients, the slip velocity on the rotor may exceed its tangential speed. [ABSTRACT FROM AUTHOR]

The present work is focused on the study of hemodynamic characteristics for tortuous arteries/veins in a pulsatile flow. This work is an extension of an earlier work by the author, which reported the hemodynamic characteristics in a steady flow situation. It is a well-known fact that various geometric parameters affect the hemodynamics, such as the diameter of vessels, the diameter of mother and daughter tubes in bifurcation, the angle between them, and their relative magnitudes. This paper is focused on the effect of tortuosity produced in straight and bifurcating tubes under pulsatile flow conditions. A heartbeat rate of 120 bpm is considered for pulsation, covering one cycle of systole and diastole. The measure of tortuosity is defined by the varying pitch and the amplitude. The present analysis is carried out computationally using ANSYS. Results are presented through secondary flow streamline, velocity profile, and its effect on wall shear stress. Key findings are that secondary vortices are observed in the bifurcated model and counter-rotating vortices are observed in the wavy tube geometry. The velocity distribution is asymmetric in the case of the plain bifurcation geometry. In the case of the wavy tube and bifurcated geometry, there is a shift in peak velocity from the inner to the outer wall, depending on the crest and trough positions of the tortuous vein. Relative change in magnitude of velocity for wavy tube depends on the depth and pitch of wavy wall of the tortuous tube. The velocity reduces with an increase in time step for unsteady flow. [ABSTRACT FROM AUTHOR]

This study explores the hydrodynamic performance of a National Advisory Committee for Aeronautics 0012 foil using computational fluid dynamics with the unsteady Reynolds-averaged Navier–Stokes (URANS) method and shear stress transport k-ω model to assess the impact of asymmetric motion parameters in manta-like swimming. The angles of attack during the mid-upstroke (αmu), mid-downstroke (αmd), and stroke duration (S) are varied to understand their effect. At low Strouhal numbers (StA = 0.2–0.35), a smaller αmd compensates for thrust loss at the start of the upstroke due to a greater αmu. At high Strouhal numbers (StA = 0.5), a greater αmd reduces negative thrust and compensates for the smaller thrust generated by a small αmu during the upstroke. Shorter stroke durations increase asymmetry, leading to more significant positive thrust peaks during the downstroke. If both the angle of attack and S are large, the slower downward speed extends negative thrust, reducing thrust peaks and lowering average thrust. A smaller stroke duration combined with a large angle of attack enhances efficiency due to a greater thrust-to-power ratio, highlighting the interplay between these parameters. A smaller S and greater αmd and StA maximize thrust and efficiency, suggesting aquatic organisms increase thrust while ensuring propulsion efficiency by using a large angle of attack and an asymmetric stroke duration. This study demonstrates how asymmetric parameters interact, providing insights into designing biomimetic underwater vehicles. The findings suggest that asymmetric dynamics enhance propulsion efficiency. [ABSTRACT FROM AUTHOR]

A hybrid power station comprising storage pump units and conventional hydropower components holds the potential to enhance the operational flexibility of basin hydroelectric regulation. The storage pumps must possess significant power capacity and operate with high efficiency to ensure viable energy storage. This study investigates the energy dissipation within a two‐stage storage pump using entropy generation theory. The numerical solution of flow energy dissipation (FED) components was obtained for various flow rates using the steady‐state single‐phase shear stress transport k–ω turbulence model. Results indicate that the return channel contributes the most to FED generation within the entire passage, with the FED proportion decreasing from 66.7% to 41.3% as the flow rate increases from 0.5QBEP to 1.2QBEP. The FED generation percentage from the runners increases from 10.4% to 46.9% with increasing flow rate, ranking second. The FED generation percentage attributed from the spiral case ranges from 10.3% to 16.7%, ranking third. Losses from the draft tube are found to be negligible. Flow pattern analysis reveals that FED generation primarily occurs at the junction of inferior flow (flow separation and vortex flow) and the main flow, where significant velocity gradients exist. [ABSTRACT FROM AUTHOR]

In view of problems such as the narrow efficiency area, large hydraulic vibration area, pressure pulsation, and serious sediment wear of turbines at the Futang hydropower station, the technical transformation of turbine runners was carried out by modifying the blade shape and increasing the blade thickness, and a combination of numerical simulations based on shear stress transport k–ω turbulence model and tests was adopted to improve the operational stability of power station units. Calculation and testing demonstrate an enlargement of the high‐efficiency zone. Specifically, the optimal efficiency of the runner increases by 0.37%, while the rated efficiency rises by 0.19%. Significant reductions are observed in pressure pulsation within the draft tube and vaneless area decrease of approximately 50%. There is a high‐frequency pressure pulsation in the vaneless zone and the runner under low‐load conditions, and the influence of dynamic and static interference gradually weakens with the increase of opening. The draft tube is prone to eccentric vortex bands under partial working conditions, which causes the unit to be affected by low‐frequency pulsation. This optimization also leads to a notable decrease in runner blade wear, with the maximum sand and water velocity reduced from 45 to 40 m/s, resulting in a 30% reduction in sand wear. Moreover, there is a substantial enhancement in the runner's stiffness, with the thickness of the blade near the high stress area of the upper crown and lower ring increasing by over 50%, and the weight of each individual blade increasing by more than 50%. These research findings validate that modifying the runner blade effectively improves flow patterns, reduces eddy current generation, minimizes pressure pulsation, widens the high‐efficiency zone, decreases wear, and enhances the operational stability of the unit. The technical transformation method and research results of this study have important guiding significance for similar technical transformation of other power stations [ABSTRACT FROM AUTHOR]

The present study investigates surfactant–carrier interactions in non-aqueous ferrofluids with magneto-rheology at different temperatures. To the authors' knowledge, such a study has not yet been reported. For this purpose, three ferrofluids—A, B, and C—were procured from Ferrotec, which had identical particles but different surfactant–carrier combinations. The study also encompasses structural and magnetic techniques to elucidate these samples' physicochemical nature. The results show that the average magnetic size of particles (10 nm) is the same for all the three fluids. The nominal value of the surfactant chain length (4.5 nm) was derived from dynamic light scattering measurements, and the Rosensweig viscosity model and the Shliomis theory were the same. The magneto-rheological properties, e.g., shear stress vs shear rate in zero field and relative increase in ferrofluid viscosity in the applied field at two different temperatures (300 and 313 K), were fitted with Rosensweig and Shliomis models. They showed some variations in surfactant chain lengths. The results suggested the presence of surfactant–carrier interactions in these colloids. This new investigation may be useful in characterizing the stability of a ferrofluid and its practical aspects. [ABSTRACT FROM AUTHOR]

Nickel slag is the solid waste obtained from the nickel smelting process. Based on the magnetic elements in nickel slag, it is a potential ingredient that could be used in magnetic compound fluid (MCF) polishing. This work discusses polishing in MCF using nickel slag and modified slag. Investigations are conducted into how MCF is affected by the amount of modified slag and nickel slag present during polishing. The connections between shear force, position, material removal rate, morphological characteristics, and polishing quality are covered. Nickel slag is mixed with CaO, the alkalinity is adjusted, and the mixture is heated to 1500 °C to fully melt and oxidize it. The resulting product is modified slag. The morphological changes in MCF slurry before and after polishing were examined using an industrial camera, and the effect of different MCF slurry components on polishing performance was analyzed throughout the polishing process. In addition, the positioning of modified slag within the magnetic cluster formed during the polishing process was determined through a scanning electron microscope and by energy dispersive x-ray spectroscopy mapping of MCF slurry. The aforementioned research establishes the polishing mechanism for nickel slag and modified slag. The experimental results indicate that the polishing effect of the experimental group with added modified slag is better than that of added nickel slag. Under the same conditions, the surface roughness was reduced by 60% when modified slag was used instead of nickel slag. It was found that the optimal process is where the modified slag content is 10%, where the material removal rate is 1.207 × 108µm3/min and the surface roughness decrease rate is 95.482%. The polishing shear force is around 2.7N, which is twice as much as that of nickel slag. [ABSTRACT FROM AUTHOR]

To investigate the variations in the flow field of centrifugal pumps with different cavitation numbers, this study utilized the shear stress transport k–ω turbulence model and Zwart–Gerber–Belamri cavitation model to examine the correlation between stall vortices and cavitation flow. The findings indicate that cavitation consistently coincides with the formation of stall vortices, and the distribution of cavitation mirrors the pattern of stall vortex structure. Cavitation tends to develop and aggregate around stall vortices, obstructing a significant portion of inlet areas within the flow channel. As the cavitation number decreases, both the area and intensity of stall vortices increase. For cavitations margins σ = 0.41, 0.23, and 0.15, we observed propagation frequencies of stall vortices at fs = 2.7, 1.8, and 0.9 Hz respectively, as these frequencies decrease relative to impeller movement until reaching near-stationary states. The pressure pulsations in various flow channels exhibit distinct phase differences; smaller cavity numbers result in larger phase disparities along with a gradual reduction in pressure pulsation amplitude. These discoveries present effective strategies for controlling and reducing both cavity formation and pressure fluctuations within centrifugal pumps, thereby enhancing overall stability. [ABSTRACT FROM AUTHOR]

Recent observations show that certain rupture phase can propagate backward relative to the earlier one during a single earthquake event. Such back‐propagating rupture (BPR) was not well considered by the conventional earthquake source studies and remains a mystery to the seismological community. Here we present a comprehensive analysis of BPR, by combining theoretical considerations, numerical simulations, and observational evidences. First, we argue that BPR in terms of back‐propagating stress wave is an intrinsic feature during dynamic ruptures; however, its signature can be easily masked by the destructive interference behind the primary rupture front. Then, we propose an idea that perturbation to an otherwise smooth rupture process may make some phases of BPR observable. We test and verify this idea by numerically simulating rupture propagation under a variety of perturbations, including a sudden change of stress, bulk or interfacial property and fault geometry along rupture propagation path. We further cross‐validate the numerical results by available observations from laboratory and natural earthquakes, and confirm that rupture "reflection" at free surface, rupture coalescence and breakage of prominent asperity are very efficient for exciting observable BPR. Based on the simulated and observed results, we classify BPR into two general types: interface wave and high‐order re‐rupture, depending on the stress recovery and drop before and after the arrival of BPR, respectively. Our work clarifies the nature and excitation of BPR, and can help improve the understanding of earthquake physics, the inference of fault property distribution and evolution, and the assessment of earthquake hazard. Plain Language Summary: Under the traditional view on earthquakes, rupture is typically considered to propagate away from where it starts, a process called forward propagation. However, recent studies show that sometimes rupture can reverse its propagation direction relative to the earlier one, which is referred to as back‐propagating rupture (BPR). The lack of a comprehensive understanding of BPR motivates us to explore why and how BPR could occur, by combining theoretical analyses, computer simulations, and experimental or natural observations. Our theoretical analyses suggest that BPR in terms of back‐propagating stress wave should almost always exist during dynamic ruptures, but can also be masked by the canceling effect of interfering waves. Nonetheless, introducing perturbations during a relatively smooth rupture process may highlight certain phases of BPR. We verify the above idea by computer simulations and available observations, showing that perturbed rupture propagation, for example, by the encountering of free surface, another rupture, and fault asperity, indeed can excite observable BPR. We further classify BPR into interface wave and high‐order re‐rupture, when there is a negligible and finite offset to the baseline of shear stress, respectively. Our work provides new insights into earthquake source process and can help improve earthquake hazard assessment. Key Points: Back‐propagating rupture (BPR) (as stress wave) is an intrinsic feature during dynamic ruptures but can be masked by destructive interferenceObservable BPR can be excited by introducing a variety of perturbations to an otherwise smooth rupture processBPR represents interface wave or high‐order re‐rupture, and can help infer the evolution behind the primary rupture [ABSTRACT FROM AUTHOR]

Shear stress levels on reverse faults are anticipated to be several times higher than on normal faults with the same pore pressure ratio. In addition, ruptures on normal faults release gravitational potential energy, whereas earthquakes on reverse faults expend work in uplifting rocks. In this study, I investigate the significance of these differences for earthquake cycles and I question whether the source of energy driving earthquakes is the same on reverse and normal faults. Based on the assumption that normal and reverse faults have the same background frictional properties and pore pressure states, I use numerical simulations with a two‐dimensional dynamic elastic‐plastic model to show that due to stress differences, earthquakes on reverse faults tend to occur less frequently, produce more coseismic slip and stress drop and involve higher slip rates than ruptures on normal faults with equivalent dimensions. The analysis also shows differences in the energy changes associated with earthquake cycles on reverse and normal faults. However, the earthquakes on both fault types result from abrupt release of elastic strain energy, which proceed and essentially drive variations in gravitational potential energy. Thus, ruptures on both normal and reverse faults are consistent with elastic rebound theory. Plain Language Summary: Normal faults found in regions experiencing extension are normally thought to have lower stress levels than reverse faults in zones of convergence. In addition, whereas the action of normal faulting causes mostly subsidence and is therefore assisted by gravity, reverse faulting tends to uplift topography, which requires that work be done against gravity. This study uses numerical modeling to address whether there are significant differences in the earthquakes on reverse and normal faults, assuming that they have identical pore pressures and frictional properties. The results show that ruptures on reverse faults are larger, more energetic and less frequent than earthquakes on normal faults. These differences are due to the higher stress levels on reverse faults than normal faults with the same dimension. The results also show than although earthquakes on normal faults are assisted by gravity, they result from an abrupt drop in elastic energy in the same way as ruptures on reverse faults. Thus, the results do not support claims that earthquakes on normal faults have a different energy source and require an explanation other than elastic rebound. Key Points: Model earthquakes on reverse faults involve higher slip rates, more slip, and larger stress drop and occur less frequently than on normal faultsModel earthquakes on both fault types involve abrupt release of elastic strain energy, much of which is dissipated plasticallyDespite differences in energetics, model earthquakes on both fault types are consistent with elastic rebound theory [ABSTRACT FROM AUTHOR]

Purpose: This study aims to establish a thermally coupled two-dimensional orthogonal cutting model to further improve the modeling process for systematic evaluation of material damage, stiffness degradation, equivalent plastic strain and other material properties, along with cutting temperature distribution and cutting forces. This enhances modeling efficiency and accuracy. Design/methodology/approach: A two-dimensional orthogonal cutting thermo-mechanical coupled finite element model is established in this study. The tanh material constitutive model is used to simulate the mechanical properties of the material. Velocity-dependent friction model between the workpiece and the tool is considered. Material characteristics such as material damage, stiffness degradation, equivalent plastic strain and temperature field during cutting are evaluated through computation. Contact pressure and shear stress on the tool surface are extracted for friction analysis. Findings: Speed-dependent friction models predict cutting force errors as low as 8.6%. The prediction errors of various friction models increase with increasing cutting forces and depths of cut, and simulation results tend to be higher than experimental data. Social implications: The current research results provide insights into understanding and controlling tool-chip friction in metal cutting, offering practical recommendations for friction modeling and machining simulation work. Originality/value: The originality of this research is guaranteed, as it has not been previously published in any journal or publication. Peer review: The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-05-2024-0162/ [ABSTRACT FROM AUTHOR]

Within the healthy human body, cells reside within the physiological environment of a tissue compound. Here, they are subject to constant low levels of mechanical stress that can influence the growth and differentiation of the cells. The liposuction of adipose tissue and the subsequent isolation of mesenchymal stem/stromal cells (MSCs), for example, are procedures that induce a high level of mechanical shear stress. As MSCs play a central role in tissue regeneration by migrating into regenerating areas and driving regeneration through proliferation and tissue-specific differentiation, they are increasingly used in therapeutic applications. Consequently, there is a strong interest in investigating the effects of shear stress on MSCs. In this study, we present a set-up for applying high shear rates to cells based on a rotational rheometer with a small-angle cone–plate configuration. This set-up was used to investigate the effect of various shear stresses on human adipose-derived MSCs in suspension. The results of the study show that the viability of the cells remained unaffected up to 18.38 Pa for an exposure time of 5 min. However, it was observed that intense shear stress damaged the cells, with longer treatment durations increasing the percentage of cell debris. [ABSTRACT FROM AUTHOR]

To solve the problem of the lack of physical properties of pedicels and the changing pattern for designing the end-effector of tomato harvesting robot and different harvesting modes, research was conducted on the physical properties of tomato pedicels and their change patterns. Using a Universal TA texture analyzer, tensile, three-point bending, and shearing tests were performed on tomato pedicels in the early firm-ripening stage. The tomato variety used was Syngenta Spectrum, cultivated seasonally with two crops per year. Spring crop tomatoes were used in this study. The experimental results provide a theoretical basis for designing tomato harvesting robots across three harvesting modes. Tensile tests measured the pull-off force and tensile strength of the abscission zone with varying diameters. These results are crucial for designing robots using a tensile harvesting mode. The location of the tomato pedicel significantly affects the shearing force. A one-way test was conducted on the shearing part. The results showed that the shearing force and energy required for the proximal pedicel are significantly greater than for the distal pedicel. To reduce the shearing force and energy needed by the end-effector's shearing mechanism on distal pedicels, a response surface test was conducted. Three factors were examined: shearing speed, angle, and distal pedicel diameter. Design–Expert software optimized these factors to minimize shearing energy and force, leading to the best shearing parameters for different distal pedicel diameters. From the three-point bending tests, the average maximum bending breaking force, bending modulus, and bending strength of the tomato abscission zone were determined. These findings offer a theoretical basis for designing tomato harvesting robots with a bending-type harvesting mode. [ABSTRACT FROM AUTHOR]

This study investigates the geometrical and mechanical properties of two cassava varieties: 'Newly Elected No. 48' and 'Jin Yue HRMUS'. We analyzed various properties, including width, length, geometric diameter, thickness, compression firmness, shape ratio, surface area, shear strength, rupture force, and shear rupture force (SRF), at different moisture content (MC) levels ranging from 35.0 to 80.0% wet basis. Our findings indicate that all mechanical properties of cassava (MPC) were significantly influenced by moisture content within this range. Specifically, as moisture content decreases, the compression rupture force (CRF) increases linearly in the vertical direction, while a quadratic relationship is observed in the horizontal direction, characterized by an initial increase followed by a decrease. Additionally, a quadratic relationship was established between moisture content and firmness. In contrast, shear fracture force and strength exhibited a quadratic relationship that decreased initially and then increased with rising moisture content. Furthermore, both compression and shear fracture forces were significantly higher in the vertical loading direction compared to the horizontal direction. Notably, the 'Jin Yue HRMUS' variety demonstrated greater mechanical strength than the 'Newly Elected No. 48'. These findings provide valuable insights for developing, optimizing, and evaluating cassava harvesting and processing machinery. [ABSTRACT FROM AUTHOR]

Atherosclerotic lesions mainly form in arterial areas exposed to low shear stress (LSS), where endothelial cells express a senescent and inflammatory phenotype. Conversely, areas exposed to high shear stress (HSS) are protected from plaque development. Endothelial extracellular vesicles (EVs) have been shown to regulate inflammation and senescence, and therefore play a crucial role in vascular homeostasis. Whilst previous studies have shown links between hemodynamic forces and EV release, the effects of shear stress on the release and uptake of endothelial EVs remains elusive. We aim to decipher the interplay between these processes in endothelial cells exposed to atheroprone or atheroprotective shear stress. Confluent HUVECs were exposed to LSS or HSS for 24 h. Large and small EVs were isolated from conditioned medium by centrifugation and size exclusion chromatography. They were characterised by TEM, Western blot, tunable resistive pulse sensing, flow cytometry and proteomics. Uptake experiments were performed using fluorescently‐labelled EVs and differences between groups were assessed by flow cytometry and confocal microscopy. We found that levels of large and small EVs in conditioned media were fifty and five times higher in HSS than in LSS conditions, respectively. In vivo and in vitro uptake experiments revealed greater EV incorporation by cells exposed to LSS conditions. Additionally, endothelial LSS‐EVs have a greater affinity for HUVECs than HSS‐EVs or EVs derived from platelets, erythrocytes and leukocytes. Proteomic analysis revealed that LSS‐EVs were enriched in adhesion proteins (PECAM1, MCAM), participating in EV uptake by endothelial cells. LSS‐EVs also carried mitochondrial material, which may be implicated in elevating ROS levels in recipient cells. These findings suggest that shear stress influences EV biogenesis and uptake. Given the major role of EVs and shear stress in vascular health, deciphering the relation between these processes may yield innovative strategies for the early detection and treatment of endothelial dysfunction. [ABSTRACT FROM AUTHOR]

This study investigates the potential of vitamin C (VC) and/or betaine (Bet) to enhance growth performance, regulate serum metabolism, and bolster antioxidant function aiming to mitigate the impact of heat stress (HS) on broilers. Two hundred Ross 308 broilers at 28 days of age were randomly assigned to five groups. The control group, housed at 24 ± 1℃, was fed a basal diet. High-temperature treatment groups, housed at 32 ± 1℃, received a basal diet with 0 (HS group), 250 mg/kg VC (HSVC group), 1000 mg/kg Bet (HSBe group), and 250 mg/kg VC + 1000 mg/kg Bet (HSVCBe group). On day 42, assessments were made on growth performance, muscle quality, serum biochemistry, and antioxidant function. Results revealed that HS significantly lowered (P < 0.05) average daily feed intake (ADFI), the degree of redness (a*) in muscles, and serum total superoxide dismutase (T-SOD) level. It also reduced (P < 0.01) average daily gain (ADG), and serum total antioxidant capacity (T-AOC) level, while increasing (P < 0.05) shear force, serum direct bilirubin (D-BIL), uric acid (UA), and malondialdehyde (MDA) levels compared with the control group. Dietary supplementation of VC and Bet, either alone or in combination, significantly decreased shear force and serum UA level, while increasing ADG and serum T-AOC, T-SOD level compared with the HS group (P < 0.05). In conclusion, the addition of VC and/or Bet to the diet proves effective in enhancing the growth performance of HS-exposed broilers through the positive regulation of serum chemical metabolism and the alleviation of oxidative damage. [ABSTRACT FROM AUTHOR]

Taking a shear wall structure in a high-intensity area of 20 floors as an example, the seismic reduction scheme of the structure was determined, and the Etabs software was used to conduct time history analysis on the seismic and non-seismic structures. The floor shear force, overturning moment, and short-term surface pressure of the isolation support were obtained. The results showed that under frequent earthquake action, the average maximum floor shear force in the direction of the isolated upper structure was only about 28 % of that of the non-isolated structure. The maximum inter story shear ratio was 0.34, and the maximum floor shear force in the direction was only about 25 % of that of the non-isolated structure. The maximum inter story shear ratio was 0.31. The average maximum overturning moment of the upper structure in the direction after isolation is about 30 % of that of the non-isolated structure. The maximum overturning moment ratio is 0.36, and the average overturning moment of the maximum floor in the direction is about 22 % of that of the non-isolated structure. The maximum overturning moment ratio is 0.26. Under rare earthquake action, the maximum inter story displacement angles in the and directions of each floor of the seismic isolation structure are 1/302 and 1/446, respectively. The maximum surface pressure value of the isolation bearing under rare earthquake is 28.9 MPa, the minimum surface pressure value is 5.58 MPa, and the maximum displacement is 579 mm, which meets the requirements of the specifications. Overall, the seismic performance of the seismic isolation structure is good, and the isolation scheme is feasible. [ABSTRACT FROM AUTHOR]

In this study, the bending and free vibrations of functionally graded material (FGM) circular plates are investigated using a new quadrilateral finite element based on a five-unknown high-order shear deformation theory. The proposed model accounts for a quadratic distribution of the transverse shear stress through the plate thickness and zero transverse shear stress at the top and bottom surfaces of the plate. The properties of the plate are changed through its thickness according to a power law in which the index varies from 0 value for a fully ceramic plate to infinity for a fully metallic plate. The concept of the physical neutral plane is introduced to avoid membrane-bending coupling. The total potential energy principle and the kinetic energy are used to derive the elementary rigidity and mass matrices. The performance and the convergence of the developed element are demonstrated through examples from the literature. Furthermore, the effect of various parameters, such as the power law index and the radius-to-thickness ratio, on the plate behavior is also considered. [ABSTRACT FROM AUTHOR]

This study's objective is to propose a full 3D finite element modeling for examining the geometrically nonlinear (NL) response of functionally graded (FG) porous materials with plates, ring, and cylindrical shapes. An improved first-order shear deformation theory (IFSDT) is utilized in order to develop the 3D solid-shell element. The governing equations are developed in a way that offers a parabolic distribution of the transverse shear strains through the FG porous shell thickness and a zero condition of the transverse shear stresses on the top and bottom surfaces. The given IFSDT solid-shell element has the ability to model any kind of shell structures and incorporates a 3D material law. In this study, two types of porosity distribution functions are considered. The effectiveness of the present IFSDT solid-shell element is demonstrated through linear (L) and NL numerical examples. The effect of the porosity distribution, porosity coefficient, power-law index, geometrical design parameters, and boundary conditions on the geometrically NL response of FG porous shells structures is evaluated. [ABSTRACT FROM AUTHOR]

Broad-based sidewall aneurysms of the carotid artery are primarily treated endovascularly. However, recurrence or rupture after treatment still poses a significant risk. Hence, reliable animal models mimicking this aneurysm type are essential for to evaluate the performance of new advanced endovascular devices. Experimental aneurysms were created in 12 New Zealand white rabbits (2.5–3.5 kg). The human carotid siphon was mimicked with an end-to-end anastomosis of both common carotid arteries. A venous pouch was sutured on the convexity to mimic a broad-based side wall aneurysm. Patency and configuration were investigated 4 weeks postoperatively by 3-T magnetic resonance angiography. To compare flow conditions of broad-based sidewall aneurysms in rabbits and humans, exemplary computational fluid dynamics simulations were performed using species-specific blood viscosity values. We were able to achieve 0% peri- or postoperative mortality. Patency was confirmed by 3-T magnetic resonance angiography in 11 of 12 aneurysms (91.7%). Aneurysm lengths ranged from 6.4 to 9.8 mm and aneurysm necks from 7.3 to 9.8 mm. Computational fluid dynamics showed simple flow profiles with one vortex in rabbit as well as in human aneurysms. Wall shear stress rates were comparable using species-specific blood viscosity values (rabbit mean 1.65 Pa vs. human mean 1.7 Pa). The broad-based curved sidewall aneurysm model mimicking the carotid siphon showed high aneurysm patency rates with low morbidity. High comparability with human flow patterns and human intranaeurysmal biomechanical forces was shown using simulations. [ABSTRACT FROM AUTHOR]

Extrusion processing of plasticized cassava starch, a prominent industrial crop, with chemical additives offers a thermo-mechanical approach to modify starch structures through physical and chemical interactions. This research investigates the interaction and morphology of thermoplastic cassava starch (TPS) blended with tetrasodium pyrophosphate (Na4P2O7), sodium tripolyphosphate (Na5P3O10), sodium hexametaphosphate (Na6(PO3)6), sodium erythorbate (C6H7O6Na), and sodium nitrite (NaNO2) via twin-screw extrusion. The effects of these additives on the chemical structure, thermal profile, water absorption, and solubility of the TPS were examined. The high temperature and shearing forces within the extruder disrupted hydrogen bonding at α-(1-4) and α-(1-6) glycosidic linkages within anhydroglucose units. Na4P2O7, Na5P3O10 and Na6(PO3)6 induced starch phosphorylation, while 1H NMR and ATR-FTIR analyses revealed that C6H7O6Na and NaNO2 caused starch hydrolysis. These additives hindered starch recrystallization, resulting in higher amorphous fractions that subsequently influenced the thermal properties and stability of the extruded TPS. Furthermore, the type and content of the added modifier influenced the water absorption and solubility of the TPS due to varying levels of interaction. These modified starch materials exhibited enhanced antimicrobial properties against Escherichia coli and Staphylococcus aureus in polyester blends fabricated via extrusion, with nitrite demonstrating the most potent antimicrobial efficacy. These findings suggest that starch modification via either phosphorylation or acid hydrolysis impacts the thermal properties, morphology, and hydrophilicity of extruded cassava TPS. [ABSTRACT FROM AUTHOR]

Based on a physical water model with a scaling factor of 0.5 and a coupled flow–heat transfer–solidification numerical model, this study investigates the influence of the submerged entry nozzle (SEN) depth on the mold surface behavior, slag entrapment, internal flow field, temperature distribution, and initial solidification behavior in slab casting. The results indicate that when the SEN depth is too shallow (80 mm), the slag layer on the narrow face is thin, leading to slag entrapment. Within a certain range of SEN depths (less than 170 mm), increasing the SEN depth reduces the impact on the mold walls, shortening the "plateau period" of stagnated growth on the narrow face shell. This allows the upper recirculation flow to develop more fully, resulting in an increase in the surface flow velocity and an expansion in the high-temperature region near the meniscus, which promotes uniform slag melting but also heightens the risk of slag entrainment due to shear stress at the liquid surface (with 110 mm being the most stable condition). As the SEN depth continues to increase, the surface flow velocity gradually decreases, and the maximum fluctuation in the liquid surface diminishes, while the full development of the upper recirculation zone leads to a higher and more uniform meniscus temperature. This suggests that in practical production, it is advisable to avoid this critical SEN depth. Instead, the immersion depth should be controlled at a slightly shallower position (around 110 mm) or a deeper position (around 190 mm). [ABSTRACT FROM AUTHOR]

Context: The fate of kids born in dairy goat production systems is a growing concern. Aims: This study aimed to evaluate the carcass characteristics and meat quality of Saanen and Saanen × Boer goat kids slaughtered at 30 and 60 days of age. Methods: We used 32 entire male goats, suckler and with access to solid food from 30 to 60 days, distributed in a completely randomised design, in a 2 (breed) × 2 (age at slaughter) factorial arrangement. We evaluated animal performance, carcass characteristics, instrumental analyses of the Quadriceps femoral muscle, and consumer perception. Key results: There was no interaction between breed and age of the goats (P > 0.05) on the initial and final liveweight, weight gain, cold carcass weight, hot carcass weight, and hot and cold carcass yields. However, age at slaughter influenced these variables (P < 0.05). The breed did not influence pH, meat colour, water-retention capacity, weight loss by cooking, or shear force (P > 0.05). However, shear force increased when goats were slaughtered at 60 days of age (P < 0.05). The muscle pH determined at 24 h after slaughter, and lipid oxidation, were lower in the meat of goats slaughtered at 60 days of age (P < 0.05), but did not differ between breeds. Higher consumer scores for flavour and appearance (P < 0.05) were attributed to the meat of crossbred animals in sensory analysis. Conclusions: Slaughtering goat kids at 60 days of age (versus 30 days of age) is an alternative for improving some aspects of meat quality. We recommend crossing Saanen × Boer to increase consumer acceptance of meat. Implications: This study is important for Saanen goat kids producers to understand that crossbreeding with the Boer breed improves carcass characteristics and meat acceptance by consumers. We compared Saanen and Saanen × Boer kid meats and found that the Saanen × Boer crossbreed contributes to increased carcass yield and greater acceptance of the meat by consumers. When comparing different slaughter ages (30 and 60 days), we observed that the carcass fat content increased and lipid oxidation in the meat decreased when the kids were slaughtered at 60 days of age. [ABSTRACT FROM AUTHOR]

This study presents an experimental investigation on the contribution of carbon fiber-reinforced polymer (CFRP) sheets in shear-strengthened beams with different strengthening schemes. Three different reinforcement types and strengthening schemes are applied (U-shaped, U-shaped with additional anchorage and fully-wrapped). The strength contribution of FRP sheets, internal stirrups, and concrete are estimated based on experimental data. Two different anchoring strategies to prevent the FRP strengthening from debonding were also present, using horizontal strips of FRP and rebars on grooves on the web of the beams. The behavior of each of the beams is discussed in terms of loaddisplacement, failure mode, strains distribution, cracking pattern, and shear force contribution. The influence of the strengthening configuration and FRP anchorage on the FRP shear contribution and total shear resistance is discussed based on the experimental. The individual contribution of FRP, stirrups and concrete are estimated based on strain data from the tests. Finally, the experimental shear capacity is compared to the recommendations of ACI 440.2R, and fib Bulletins 14 and 90. [ABSTRACT FROM AUTHOR]

Limited research has been carried out to investigate the local damage features of reinforced concrete (RC) beams under close‐in explosions. To better capture the local damage features of rectangular cross‐sectional RC beams, a numerical study on the RC beams subjected to close‐in explosions based on the calibrated Karagozian & Case (K&C) concrete model was conducted in LSDYNA. First, a systematic calibration of the K&C model for concrete was performed in the single‐element numerical analysis. Calibration of the K&C model consists of parameter determination for the new strength surfaces, modification of the damage function to better feature the tensile behavior of concrete, elimination of the element size effect by introducing an element size factor and determination of the scaled damage factors. The new strength surfaces are verified and determined through both the approximation calculation method and the parameter fitting method. And the damage function was modified by reducing the termination of λ to better characterize the brittleness of concrete and feature the tensile failure. A comparison between the numerical results and the corresponding experimental results demonstrates that the calibrated K&C model and established FEM model of RC beams subjected to close‐in explosions can well characterize the local damage features of RC beams. On this basis, a further parameter analysis on the factors influencing the local damage response of RC beams was conducted by considering reinforcement details (stirrup spacing and longitudinal reinforcement diameter) and charge details (charge mass and aspect ratio). Results show that the close‐in explosions destroyed the concrete corners in the blast surface with shear stress first and the side shear failure of concrete corners weakens the concrete core strength and contributes to the greater loss of concrete core. Rear spalling damage was initially caused by the bond failure between the tensile longitudinal reinforcement and the surrounding concrete. Furthermore, increasing stirrup spacing, tensile longitudinal reinforcement diameter, and charge mass contribute to the increase in local damage sizes. [ABSTRACT FROM AUTHOR]

Objective: Tortuous microvessels are characteristic of microvascular remodeling associated with numerous physiological and pathological scenarios. Three‐dimensional (3D) hemodynamics in tortuous microvessels influenced by red blood cells (RBCs), however, are largely unknown, and important questions remain. Is blood viscosity influenced by vessel tortuosity? How do RBC dynamics affect wall shear stress (WSS) patterns and the near‐wall cell‐free layer (CFL) over a range of conditions? The objective of this work was to parameterize hemodynamic characteristics unique to a tortuous microvessel. Methods: RBC‐resolved simulations were performed using an immersed boundary method‐based 3D fluid dynamics solver. A representative tortuous microvessel was selected from a stimulated angiogenic network obtained from imaging of the rat mesentery and digitally reconstructed for the simulations. The representative microvessel was a venule with a diameter of approximately 20 μm. The model assumes a constant diameter along the vessel length and does not consider variations due to endothelial cell shapes or the endothelial surface layer. Results: Microvessel tortuosity was observed to increase blood apparent viscosity compared to a straight tube by up to 26%. WSS spatial variations in high curvature regions reached 23.6 dyne/cm2 over the vessel cross‐section. The magnitudes of WSS and CFL thickness variations due to tortuosity were strongly influenced by shear rate and negligibly influenced by tube hematocrit levels. Conclusions: New findings from this work reveal unique tortuosity‐dependent hemodynamic characteristics over a range of conditions. The results provide new thought‐provoking information to better understand the contribution of tortuous vessels in physiological and pathological processes and help improve reduced‐order models. [ABSTRACT FROM AUTHOR]

The lining of blood vessels is constantly exposed to mechanical forces exerted by blood flow against the endothelium. Endothelial cells detect these tangential forces (i.e., shear stress), initiating a host of intracellular signaling cascades that regulate vascular physiology. Thus, vascular health is tethered to the endothelial cells' capacity to transduce shear stress. Indeed, the mechanotransduction of shear stress underlies a variety of cardiovascular benefits, including some of those associated with increased physical activity. However, endothelial mechanotransduction is impaired in aging and disease states such as obesity and type 2 diabetes, precipitating the development of vascular disease. Understanding endothelial mechanotransduction of shear stress, and the molecular and cellular mechanisms by which this process becomes defective, is critical for the identification and development of novel therapeutic targets against cardiovascular disease. In this review, we detail the primary mechanosensitive structures that have been implicated in detecting shear stress, including junctional proteins such as platelet endothelial cell adhesion molecule-1 (PECAM-1), the extracellular glycocalyx and its components, and ion channels such as piezo1. We delineate which molecules are truly mechanosensitive and which may simply be indispensable for the downstream transmission of force. Furthermore, we discuss how these mechanosensors interact with other cellular structures, such as the cytoskeleton and membrane lipid rafts, which are implicated in translating shear forces to biochemical signals. Based on findings to date, we also seek to integrate these cellular and molecular mechanisms with a view of deciphering endothelial mechanotransduction of shear stress, a tenet of vascular physiology. [ABSTRACT FROM AUTHOR]

AbstractTo study scour-resistant applicability, 6–10% mass ratio of polyurethane (PU) was added to sulphoaluminate cement (SAC) and ordinary Portland cement (OPC) grouts to generate OPCPU and SACPU. Sodium silicate (SS) with slurry volume ratio of 1:1–5:1 was added to SAC and OPC grouts to generate OPCSS and SACSS. The water-cement ratio (w/c) of grout was 0.8–1.5. Fresh-state properties and mechanical properties were investigated. Hydrated minerals and microstructures were analyzed, scouring tests were conducted considering key formulations. The results indicated that SACSS and OPCSS have a shorter setting time and higher strength, which makes them suitable as scour resistance materials. At the w/c of 1.0, OPCSS with a volume ratio of 3:1 and SACPU with 6% PU were selected for scour resistance tests. It showed that maximum scour depths and sediment transports were 7.0–12.2 and 1.1–1.2% as those without reinforcing conditions. The critical shear stress on the seabed under reinforcement is ∼103 times greater than the bed shear stress. This inhibits the occurrence of scouring. The study evaluated the applicability of cementitious reinforcement for scour resistance. This study analyzed material and mechanical properties, hydrated minerals, and microstructures, and conducted scour tests to optimize grouting material ratios for seabed scour protection, providing references for soil reinforcement and grouting protection. [ABSTRACT FROM AUTHOR]

Separation of equally sized particles distinguished solely by interfacial properties remains a highly challenging task. Herein, a particle fractioning method is proposed, which is suitable to differentiate between polymer‐grafted microparticles that are equal in size. The separation relies on the combination of a pressure driven microfluidic flow, together with simultaneous light illumination and temperature control. Heating the solution forces thermo‐responsive surface grafts to undergo a volume phase transition and therefore locally changing the interfacial properties of the microparticles. Light illumination induces the phoretic/osmotic activity of the microparticles and lifts them into a higher plane, where hovering particles experience a different shear stress proportional to the height. The light‐induced hovering height depends on the interfacial properties, and this complex interaction leads to different movements of the microparticles as a function of their surface grafting. The concepts are visualized in experimental studies, where the complex physical principle provides a simple method for fractioning a binary mixture with at least one thermo‐responsive polymer graft. [ABSTRACT FROM AUTHOR]

Fault rupture dynamics is expected to be significantly affected by the geometry of fault system, especially for orthogonal faults. However, the rupture behaviours of orthogonal faults, especially the coseismic interactions, are far from fully understood. Here, we present experimental results from a series of laboratory earthquakes to elucidate the effect of the stress state and initiation location on the rupture behaviours of orthogonal faults. Our results reveal a phase diagram of rupture behaviours of orthogonal faults, which is collectively controlled by stress state and rupture initiation location. For events initiating from the main fault, the rupture cannot jump to the branch, which may be due to the clamping effect or the inhibited shear stress accumulation on the branch. On the contrary, events initiating from the branch can persistently trigger ruptures of the main fault. This difference highlights the directional effect associated with the rupture of orthogonal faults. Further, the rupture length of triggered ruptures on the main fault is controlled by the stress state of the fault system. With the increase of the ratio between the shear stress and normal stress, the rupture length of the main fault increases. Our results reproduce the rupture behaviours of orthogonal faults, which may provide insights into the rupture characteristics of natural earthquakes. [ABSTRACT FROM AUTHOR]

In a comprehensive study, effects of casting methods such as gravity sand casting, squeeze casting and composite casting in semi-solid state and casting variables (i.e., cooling rate, stirring speed and shear forces) on the microstructure, porosity formation and mechanical properties of A356–SiC nanocomposites were investigated thoroughly. First, a step-like sample was used to make the sand casting samples to study the effects of different cooling rates that each step experienced on the properties of nanocomposite, where squeeze casting and composite casting samples were produced in a metallic mold. Once the samples were produced and prepared for the studies, grain size, shape factor, dendritic and globular microstructure, amount of eutectic phase and mechanism of porosity formation, mechanical properties and fracture surface of the samples were analyzed precisely and discussed. In addition, the effects of stirring forces, time and temperature, used in the squeeze casting and the compo-casting methods, on the morphology of the dendritic arms of aluminum matrix composites were investigated and compared with the microstructure of castings produced by conventional gravity casting. It was discovered that switching from the gravity sand casting process to the squeeze casting process delivers a less dendritic and more refined microstructure in the nanocomposite. However, composite castings produced in the semi-solid state by applying high stirring shear forces for 80 s produce the finest and the most globular and spherical microstructure. This optimized globularization condition provides desired microstructure and mechanical properties for this type of nanocomposite. The dominant failure mechanism in the composite casting samples produced in semi-solid state was ductile, where it was a mix of ductile/brittle for the squeeze casting and brittle for the sand casting samples. Finally, the effects of globularization temperature on the nucleation and growth of primary α grains were studied. [ABSTRACT FROM AUTHOR]

The complex composition of braised pork, including lean meat, pigskin, and fat, makes it difficult for sensory evaluation of its texture properties. This study investigated the correlation between sensory texture attributes and physicochemical properties to achieve an objective and comprehensive evaluation of the texture of braised pork. Sensory analysis demonstrated that the overall texture acceptability of braised pork was significantly and negatively influenced by sensory texture attributes (including sensory hardness, chewiness, and toughness), while it was positively impacted by sensory adhesiveness, softness, and juiciness. Shear force and texture profile analysis (TPA) variables, reflecting mastication behavior, were used to characterize the textural properties of braised pork. They were closely related to water distribution, with a higher proportion of immobilized water (P21), indicating a higher water holding capacity and a more tender texture. Correlation analysis between sensory texture attributes and physicochemical properties through partial least squares regression further revealed significant associations between shear force, TPA variables, and sensory texture attributes. Moreover, the proportion of immobilized water (P21) significantly and negatively affected sensory hardness and chewiness, whereas the proportion of free water (P22) significantly influenced sensory toughness. Sensory texture attributes could be well predicted by the physicochemical properties by projecting test samples onto calibration models established by known samples. Therefore, a combination of sensory and instrumental measures can reliably reflect the texture properties of braised pork. Practical Application: The combination of sensory and instrumental methods is an effective strategy to accurately and objectively evaluate the texture properties of braised pork, which overcomes the limitations caused by the complexity of the composition and texture traits of braised pork. The accurate evaluation and standardization of texture properties is an important premise for the repeatable and stable cooking of traditional braised pork. Furthermore, this research method and findings can also be applied to guide the procedural optimization of smart appliances (e.g., induction cookers) for cooking braised pork. [ABSTRACT FROM AUTHOR]

Autologous arteriovenous fistula (AVF) is a commonly used vascular access (VA) for hemodialysis, and hemodynamic changes are one of the main factors for its failure. To explore the effect of geometry on the hemodynamics in the AVF, a modified model is built with a gradual and smooth turn at the anastomosis and is compared with the traditional model, which has an abrupt sharp turn at the anastomisis. Transient computational fluid dynamics (CFD) simulations were performed for the comparison and analysis of the hemodynamic fields of the two models at different stages of the pulse cycle. The results showed that the low shear stress region and high oscillatory shear stress region in the modified AVF model coincided with regions of intimal hyperplasia that have been identified by previous studies. A comparison with the blood flow velocities measured in vivo was performed, and the error between the simulation results and the medical data was reduced by 22% in the modified model, which verifies the rationality and utility of the modified model. [ABSTRACT FROM AUTHOR]

Summary: The objective of this study is to develop a model that is based on water diffusion for predicting the cleaning procedure during water rinse of Clean‐in‐Place operation. The kinetics of dairy foulant generated by using dairy product was analysed. The foulants removal with three different moisture contents (6.7%, 13.4%, and 39.3%) and four different wall shear stresses (WSS, 0.013, 0.39, 0.84, and 2.42 Pa) were evaluated. It was found that the lag time decreased with increase of WSS. In addition, the maximal removal and cleaning rate was found to increase along with the elevation of the wall shear stress. Moisture contents of the deposit determines the minimum magnitude of the wall shear stress to initiate the removal process. By combining the water diffusion and removal kinetics obtained from the experiment, a model to describe the removal of the deposits has been developed. Diffusion assuming 1‐D infinite plate was used to simulate the change in moisture content. The model confirms that the foulants with a higher initial moisture content is more rapidly removed. Furthermore, the foulant removal is affected by the permeation of water into foulants as well as the wall shear stress. [ABSTRACT FROM AUTHOR]

Summary: This study investigated the effect of non‐selenium glutathione peroxidase (NSGPx) activity of Peroxiredoxin 6 (Prdx6) on beef tenderness. Longissimus thoracis et lumborum (LTL) muscle from six cattle were obtained at 30 min post‐mortem. Samples from each muscle were randomly assigned to each of four treatment groups: being incubated in H2O2 (simulation of oxidative stress), mercaptosuccinic acid (MA; inhibiting NSGPx activity), N‐acetyl‐L‐cysteine (NAC; inhibiting oxidative stress and increasing NSGPx activity), and saline (control), respectively. Results indicated that cells increased the expression of Prdx6 and NSGPx activity to resist oxidative stress. The inhibition of NSGPx activity group (MA) significantly decreased the Warner‐Bratzler shear force and increased the degradation of desmin. Moreover, both the H2O2 and the MA treatment significantly increased the Ca2+ concentration in the sarcoplasm, cell apoptotic rate, and caspase 9 and 3 activity. These results demonstrated that inhibiting NSGPx activity of Prdx6 could accelerate beef tenderization by promoting mitochondrial apoptosis. [ABSTRACT FROM AUTHOR]

Summary: This study investigated the effects of skin‐on and skin‐off processing methods on processing efficiency, product yield and meat quality of goat carcasses. A total of twenty‐seven goats (nine/treatment, 6 months old) were processed using three methods: (1) skin‐on for ethnic consumers, (2) skin‐off for traditional consumers and (3) skin‐off‐late (skin removal after chilling) for primarily traditional consumers, with an option for ethnic consumers with skin‐on. Processing times (slaughter, chilling, fabrication) and yields (chilling and fabrication) were compared. Meat quality and appearance were evaluated using sarcomere length, Warner‐Brazler shear force, collagen content and muscle colour. Skin‐on carcasses required significantly longer chilling times to reach the internal body temperature at ≤4.4 °C (9.5 h) compared to skin‐off carcasses (7 h), presumably due to the presence of the skin. Despite this, the total processing time from stunning to fabrication showed no significant difference across treatments, although the skin‐off‐late carcasses had longer fabrication times due to the skin removal step (P < 0.05). Dressing yield was lower in the skin‐off group, and fabrication yield was reduced in the skin‐off‐late carcasses (P < 0.05). Skin‐on and skin‐off‐late carcasses showed longer sarcomere lengths and lower Warner Bratzler shear forces than skin‐off carcasses (P < 0.05). Additionally, the skin‐on group had higher collagen content than the skin‐off group. Muscle L* values were higher in skin‐on and skin‐off‐late carcasses (P < 0.05), with no significant differences in a* and b* values across treatments. This research highlights the potential benefits of the skin‐off‐late method for goat farmers, processors and consumers, offering improved dressing yield, meat tenderness and visual appearance. The skin‐off‐late method also provides an alternative processing option that could satisfy both traditional and ethnic consumer preferences. [ABSTRACT FROM AUTHOR]

The thermodynamic instability of conventional aqueous foam‐stabilized surfactants is a critical bottleneck in the construction of porous materials. Herein, a novel strategy is proposed for preparing a capillary foam based on Chlorella and utilizing it as a template for constructing porous materials with high‐efficiency adsorption. The capillary foam was stabilized by Chlorella particles enclosed within a gel network of oil bridges connecting the particles (capillary suspension). Chlorella particles, which act as stable particles, form oil bridges and are distributed at the phase interface of the capillary foam. These particles exhibited resistance to shear forces, allowing the formation of a long‐term stable capillary foam. Using this foam as a template, a porous material with outstanding adsorption performance for Methylene Blue (MB) and Brilliant Green (BG) dyes was successfully constructed. Additionally, the material exhibited a sustained high adsorption performance even after five thermal regeneration‐adsorption cycles. In conclusion, this study presents a green and straightforward method for constructing capillary foams with high stability, which is a promising approach for developing porous materials with exceptional adsorption and regeneration properties for dyes. [ABSTRACT FROM AUTHOR]

Considering the importance of understanding the propagation of transient waves in the piezomagnetic solids, the thermal effect on the transient behavior of a piezomagnetic half-space subjected to dynamic anti-plane load is investigated analytically in this paper. Using one-sided, two-sided Laplace transformation and Cagniard–de Hoop (CH) technique, an efficient and accurate analytical derivation for the solution of the anti-plane displacement, shear stress, magnetic potential, and induction in Laplace domain is presented. The study shows that the thermal stresses developed in x -axis and y -axis directions have significant influence on the transient response of the half-space. The magnetic induction B x increases obviously when the thermal stress is applied in x -axis direction, while it decreases when the thermal stress is applied in y -axis direction. Approaching time of magnetic induction B x and B y will become longer with higher thermal stress in x -axis direction. With the growth of the thermal stress in x -direction, contribution from the electromagnetic–elastic head (EH) wave increases, while the contribution from the shear elastic (SE) wave and the static value of shear stress decrease. [ABSTRACT FROM AUTHOR]

In this work, we present a new two-scale finite-strain plate theory for highly heterogeneous plates described by a repetitive periodic microstructure. Two scales exist, the macroscopic scale is linked to the entire plate and the microscopic one is linked to the size of the heterogeneity. This work aims to propose such a theory for thick plates in a nonlinear setting when the thickness and the size of heterogeneities are of the same order of magnitude. The homogenization theory for large deformation with growth is suitable for the modelization of nearly incompressible plant tissue. This model is suitable for wavy leaves. For thick plates, the transverse normal stress and transverse shearing are modelized at both microscopic and macroscopic levels. At the macroscopic level, we consider a nonlinear Cosserat plate model. At the microscopic level, we impose that the average of contribution of the microscopic displacement to rotation angles is equal to zero. We also deal with the problem of boundary layer problem near the lateral boundary. The model recently proposed by Pruchnicki is valid for thin heterogeneous plates; we present an extension for thick plates that takes into account both transverse normal stress and shearing. This model is equivalent to the first model presented but it involves a second-order derivative of the macroscopic displacement field. [ABSTRACT FROM AUTHOR]

Low-permeability rock is suitable as the host rock of an underground repository for radioactive waste disposal; however, minor faults might develop there. Investigating the shear capability (= shear compliance) of those faults is crucial because they could be elastically sheared by the thermal effect of the waste to damage the waste's engineered barriers. This study performed constant-head step-injection tests along with a recently developed packer-pressure-based extensometer method for assessing the applicability of this method to investigate the shear capability of minor faults. Herein, two neighboring minor faults (A and B) in siliceous mudstone were evaluated. The results showed that fault A, with centimeter-thick fault breccia, exhibited high shear capability, whereas fault B, with millimeters or less-thick fault breccia, displayed low shear capability despite containing an incohesive fault rock. An elastic shear displacement occurred for fault A during injection and reached 15–66 mm when the test-section pressure increased from 4.1 to 4.3 MPa. Here, the shear capability was 101 mm/MPa or more. Conversely, fault B had cohesion, and no shear displacement was detected even when the test-section pressure increased from 4.0 to 6.0 MPa. In this case, the shear capability was 10−1 mm/MPa or less. The estimated shear capabilities were consistent with the results from previous shear experiments, and therefore, the applied method helps investigate the shear capabilities of minor faults. Highlights: The packer-pressure-based extensometer method was applied to two neighboring minor faults to investigate their shear capability. The estimated shear capability was corroborated with the results from previous shear experiments. The applied method helps investigate the shear capability of minor faults. [ABSTRACT FROM AUTHOR]

The mechanical characteristics of anchor cable (AC) play a vital role in determining the design of prestressed support for roadways in deep coal mines. To investigate the shear mechanical properties of AC, a multifunctional testing device for AC was developed, which can conduct mechanical behavior tests such as anchoring, tensioning, and shearing on full-size AC. The research results showed that under shear stress, the AC presented a Z-shaped or S-shaped morphology, and the failure morphology of the rock surrounding the partial contact area with the AC was consistent with the shape of the AC. The initial tensioning force of the AC and the method used to anchor it greatly influenced the shear force, axial force, and shear deformation experienced by the AC. The analysis of the test results involved examining the shear force and deformation properties of the AC at various stages, and proposing the stress and deformation pattern of the AC when subjected to shear forces. The AC was analyzed to determine its bending deflection, rotation angle, bending moment, and shear force distribution pattern, which provided insights into the composite fracture mechanism involving bending, tensile, and shear stress. Highlights: The multifunctional testing device for anchor rods (cables) was developed, which can achieve mechanical behavior testing such as anchoring, tensioning, and shearing of full-size AC. The AC's shear force–displacement curve can be categorized into five stages, each characterized by distinct shear forces and deformation mechanisms. The influence of the initial pretightening force of the anchor cable and the anchoring method on the shear force, axial force, and shear deformation of the anchor cable is revealed. [ABSTRACT FROM AUTHOR]

CO2 sequestered in deep coal seams (> 800 m) exists as supercritical state (ScCO2) due to high temperature and pressure, and the injection induced non-uniform in-situ stress changes would cause shear slip, affecting fracture permeability and increasing CO2-leakage risk. Thus, understanding the shear-induced permeability evolution of coal fracture subjected to ScCO2 soaking is crucial. A series of shear-flow tests under different confining pressure were conducted to study the permeability evolution of un-soaked and ScCO2-soaked fractured coal samples. The surface characteristics before and after the test was measured with 3D scanning methods to examine the shear-induced alteration of fracture geometries. The results show that, as the shear displacement increases, the permeability of coal fracture decreases at the early shearing stage, then increases due to shear dilation, but was offset by the gouge formation at the residual shear stages, leading to permeability reduction ranging from 9 to 70% under different confining pressure. After ScCO2 soaking, the mechanical strength of surface asperities is greatly reduced, resulting in an increase of 26% in asperity damage volume and a decrease of 56–90% in permeability after shear. The shear behavior after peak stress of fractured coal samples shows shear hardening, and based on which a shear constitutive model of coal fracture was built to calculate the gouge production related to shear plastic work. A theoretical permeability model was built, showing a good application to describe the ScCO2 effect on permeability of coal fracture subjected to shear stress. Highlights: Triaxial shear test was conducted to investigate the supercritical CO2 soaking effect on the permeability of coal fracture under shear slip. Long-time supercritical CO2 soaking-induced surface asperities degradation significantly affects the permeability evolution of coal fracture during shear. A theoretical model was built to characterize the supercritical CO2 soaking effect on the permeability evolution during shear. [ABSTRACT FROM AUTHOR]

Curved shells are increasingly utilized in applied engineering due to their shared characteristics with other sandwich structures, flexibility, and attractive appearance. However, the inability of controlling and regulating vibrations and destroying them afterward is a challenge to scientists. In this paper, the curve shell equations and a linear quadratic regulator are adopted for the state feedback design to manage the structure vibrations in state space forms. A five-layer sandwich doubly curved micro-composite shell, comprising two piezoelectric layers for the sensor and actuator, is modeled by the fourth-order shear deformation theory. The core (honeycomb, truss, and corrugated) is analyzed for the bearing of transverse shear forces. The results show that the honeycomb core has a greater effect on the vibrations. When the parameters related to the core and the weight percentage of graphene increase, the frequency increases. The uniform distribution of graphene platelets results in the lowest natural frequency while the natural frequency increases. Furthermore, without taking into account the piezoelectric layers, the third-order shear deformation theory (TSDT) and fourth-order shear deformation theory (FOSDT) align closely. However, when the piezoelectric layers are incorporated, these two theories diverge significantly, with the frequencies in the FOSDT being lower than those in the TSDT. [ABSTRACT FROM AUTHOR]