Search

The present study is concerned with the analytical solution of Riemann problem for conservation laws of van der Waals gas. By utilizing Rankine–Hugoniot conditions and Lax entropy condition, we derive classical wave solution of Riemann problem and analyze their properties. Also, it is observed here that van der Waals gasdynamics system is more complex in comparison to ideal gasdynamics case. Further, the effect of presence of intermolecular forces of attraction between the particles and variation of covolume of the gas on the density and velocity distribution across the simple wave, shock wave and contact discontinuities is discussed. [ABSTRACT FROM AUTHOR]

The jet can be applied to the yaw control of a projectile, however, the complex interaction of the jet with the supersonic mainstream makes the flow field complex and yaw force unpredictable. To reveal the evolution of flow structures under different pressure ratios (PRs), or momentum flux ratios, a transverse sonic jet injected into a supersonic laminar crossflow has been studied numerically. Large-eddy simulations are employed to simulate the flow fields and evolution tendency of flow structures under different PRs of 10, 50, 100, 300, and 500. Our results show clearly the shock and flow structures of the jet interaction with crossflow under different PRs. Moreover, we find that, with the increase of PR, a larger upstream recirculation zone (RZ) and jet shock core appear, which accelerates the transformation of the bow shock (BoS) and the instability of the jet shear layer due to its stronger interaction with the crossflow. In addition, a high PR also accelerates RZ instability and produces a strong compressing effect on the major counter-rotating vortex pair in the jet flow, which makes the streamwise vortex tube stronger in the wake. These findings provide important information for applications of jet control of projectiles. [ABSTRACT FROM AUTHOR]

Masonry structures are highly vulnerable to collapse when subjected to blast shock waves. However, existing research primarily concentrates on the response of masonry walls under blast loading, with limited investigation into the response of three-dimensional full-size masonry structures. Therefore, this paper investigates the effects of blast distance and blast equivalent on masonry structure damage using the continuum-discontinuum element method (CDEM). The integration of the HJC element constitutive model, fracture energy contact surface constitutive model, and shock wave fast imposition algorithm into CDEM enables efficient calculation of the damage process of masonry structures under the influence of shock waves. Initially, the blasting process of a masonry wall was numerically simulated, yielding results consistent with experimental findings. Subsequently, the entire damage process of a 3D full-size masonry structure under blast loading was simulated. The findings indicate that at short distances from the blast, the wall may detach directly from the concrete frame due to shock wave overpressure reaching the material's ultimate compressive strength, leading to structural instability. As the distance increases beyond a critical value, the shock wave's effect weakens, and wall damage transitions gradually to bending damage. [ABSTRACT FROM AUTHOR]

Nuclear explosion in a densely populated area is the worst that can happen to any country in the world due to enormous loss of life, property and severe economic damage. Nuclear explosions immediately cause radiological damage and destruction of infrastructure. This hydro-magnetic shock propagation due to blast gives rise to simultaneous signals around the world. The effect of shockwave from nuclear explosion is an area that can be used to handle post and pre-disaster from nuclear explosion. This study focuses on the effects of shockwave on solid objects oriented in different formation. Experiments conducted in a horizontally placed shock tube and a solid object holder on the floor of the test section. These solid objects placed inside the test section of a shock tube collided with a planner shock wave which was generated by rupturing a diaphragm of different thickness. Four high speed pressure transducers strategically placed at different locations of this shock tube were used to characterize the blasts as well as interaction with the samples. A high-speed Kronos and Phantom camera were used to record the exact moment of interaction to characterize the solid objects under the impact of different shock waves. Representative results of these experiments are reported here along with review of previous work done in this area. [ABSTRACT FROM AUTHOR]

The aeroelastic responses and nonlinear behaviors of a two-dimensional panel impinged by an oscillating Mach stem shock are investigated through theoretical analysis. Through the nonlinear descriptors, such as Poincaré maps and Largest Lyapunov exponents, the panel with oscillating shock impingement is found to exhibit multiple responses, including single/multi-periodic limit cycle oscillation, quasi-periodic motion, and chaotic motion. Without altering the in-plane force, which is the principal source of structural nonlinearity, the shock oscillation complicates the nonlinear behaviors of the panel. With shock oscillation, the original divergence instability is transformed into post-divergence limit cycle oscillation, and the flutter response exhibits rich nonlinear characteristics. The effect of initial shock impingement location, shock oscillating amplitude, and shock oscillating frequency are disclosed through the bifurcation diagram, which significantly influences the nonlinear characteristics of the panel response. By reasonably adjusting the shock oscillating parameters, unpredictable nonlinear behaviors, especially chaotic motions, can be avoided. [ABSTRACT FROM AUTHOR]

For solving the time fractional conservation laws with discontinuous solutions such as shock waves, current feasible methods are the implicit finite-volume TVD schemes that employ the Lax-Friedrichs fluxes corrected by the limited slopes. However, the schemes are hard to implement when the fractional order α is close to zero since in their implementation there are still no efficient methods to solve the strongly nonlinear spacial discrete systems at discrete times. We, aiming at increasing the implementation efficiency of the schemes above, develop two multigrid methods to solve these nonlinear spacial discrete systems. Numerical tests show that both multigrid methods have good convergence for relatively larger α , and the second one has an advantage in that its convergence is affected slightly when the order α decreases to zero. [ABSTRACT FROM AUTHOR]

Recent measurements of primary and secondary CR spectra, their arrival directions, and our improved knowledge of the magnetic field geometry around the heliosphere allow us to set a bound on the distance beyond which a puzzling 10-TeV "bump" and certain related spectral features cannot originate. The sharpness of the spectral breaks associated with the bump, the abrupt change of the CR intensity across the local magnetic equator (90 ° pitch angle), and the similarity between the primary and secondary CR spectral patterns point to a local reacceleration of the bump particles out of the background CRs. We argue that, owing to a steep preexisting CR spectrum, a nearby shock may generate such a bump by boosting particle rigidity by a mere factor of ∼ 1.5 in the range below 50 TV. Reaccelerated particles below ∼ 0.5 TV are convected with the interstellar medium flow and do not reach the Sun. The particles above this rigidity then form the bump. This single universal process is responsible for the observed spectral features of all CR nuclei, primary and secondary, in the rigidity range below 100 TV. We propose that one viable candidate is the system of shocks associated with ∊ Eridani star at 3.2 pc of the Sun, which is well aligned with the direction of the local magnetic field. Other shocks, such as old supernova shells, may produce a similar effect. We provide a simple formula that reproduces the spectra of all CR species with only three parameters uniquely derived from the CR proton data. We show how our formalism predicts helium, boron, carbon, oxygen, and iron spectra, for which accurate data in GV-TV range exist. Our model thus unifies all the CR spectral features observed below 50 TV. [ABSTRACT FROM AUTHOR]

In fluid dynamics, the Atwood number is a dimensionless parameter that quantifies the density difference between two fluids. It is calculated as A t = (ρ 1 − ρ 2) / (ρ 1 + ρ 2) , where ρ 1 and ρ 2 represent the densities of the respective fluids. This research employs high-fidelity numerical simulations to examine the Atwood number impacts on Richtmyer–Meshkov (RM) flows triggered by a shocked forward-pentagonal bubble. Five distinct gases — SF 6 , Kr, Ar, Ne, and He — are considered within the forward-pentagonal bubble, encompassed by N 2 gas. In these simulations, a third-order discontinuous Galerkin approach is applied to solve a two-dimensional set of compressible Navier–Stokes-Fourier (NSF) equations for two-component gas flows. To discretize space, hierarchical modal basis functions based on orthogonal-scaled Legendre polynomials are employed. This approach simplifies the NSF equations into a set of ordinary differential equations over time, which are solved using an explicit third-order SSP Runge–Kutta algorithm. The numerical results highlight the notable impact of the Atwood number on the evolution of RM flows in the shocked forward-pentagonal bubble, a phenomenon not previously reported in the literature. The Atwood number exerts a significant influence on the flow patterns, leading to intricate wave formations, shock focusing, jet generation, and interface distortion. Moreover, a comprehensive analysis of the these impact elucidates the mechanisms driving vorticity formation during the interaction process. Additionally, the study conducts a thorough quantitative examination of the Atwood number impacts on the flow fields based on integral quantities and interface features. [ABSTRACT FROM AUTHOR]

In this paper, we discuss double-pulse laser peening (DPLP) as surface enhancement technology. Although single-pulse laser peening (SPLP) has yielded excellent results across various applications, its processing performance and efficiency are limited. The DPLP technique involves two laser pulses with a controlled irradiation interval and intensity, enhancing laser absorption through the plasma plume and generating high-amplitude laser-induced shock waves. This study involved conducting DPLP experiments on stainless steel, comparing the outcomes with those of conventional SPLP to assess DPLP's functionality. After the initial prepulse irradiation, the subsequent main pulse was timed and irradiated onto the stainless steel. We evaluated the surface hardness to ascertain the impact of laser peening. The findings indicated that the surface hardness achieved with DPLP was up to 64% greater than that with SPLP. Additionally, the surface hardness achieved through DPLP depended on the delay time between the pulses and the intensity of the initial prepulse. These findings suggest that DPLP can significantly enhance surface hardness, providing a potential pathway for improving material performance in various industrial applications. Furthermore, simulation experiments of DPLP were performed using a one-dimensional simulation code that calculates the laser-matter interaction during the peening process. The pressure profiles generated by the simulation closely matched the experimentally derived hardness profiles, confirming the simulation's ability to predict the mechanical effects induced by DPLP on the target sample and assist in further optimization of the DPLP process. [ABSTRACT FROM AUTHOR]

Supersonic wind tunnel experiment is one of the important measurements for developing advanced gas turbines, and supersonic multi-hole probes are sophisticated tools to measure pneumatic parameters in such experiments. However, shock waves form around the probe head in supersonic flow, which affect the accuracy of results. In this study, a supersonic five-hole probe is selected as the research object. Firstly, a compound five-hole pressure-temperature probe was designed and produced with 3D-printing technology. Then, the shock wave spectrum was numerically calculated by three methods, which were the Mach number, density gradient, and shock function; in contrast to the other two methods, the shock function could accurately identify the types and ranges of shock and expansion waves. The results show that a strong shock wave is formed at the front section of the probe head, and the shock wave generated around the pressure measuring tube affects the total pressure and Mach number of the flow field, which causes the increase of entropy. The intensity of the shock wave at the head of the pressure measuring tube is the largest, causing a decrease in the total pressure around the flow field. Afterwards, to reduce the calculation errors caused by neglecting the compressibility of gases and the entropy increase, a gas compression factor δs was introduced. It is proved that the error of the calculated pneumatic parameters is less than 5% and 10% in subsonic and supersonic condition, respectively, with the gas compression factor considered. The research results of this paper provide theoretical reference for the design and use of pneumatic probes during subsonic to supersonic flow. [ABSTRACT FROM AUTHOR]

In this paper, we study the effect of explosion pressure relief from different angles of outlet in confined areas under methane-air premixed gas with a methane volume concentration of 9.5%. Results showed that increasing the angle of explosion pressure relief outlet from 30° to 150° generates a subsequent change in the overpressure attenuation rate of the straight pipeline segment (range 19.51–33.96%). Notably, the explosion pressure relief efficiency is most significant under working conditions of 60°–75°, and the overpressure attenuation rate is 30.21%–33.96%. The overpressure attenuation rate of the straight pipeline exhibits a non-monotonic relationship with the explosion pressure relief outlet angles, while the overpressure peak is positively correlated with the explosion pressure relief outlet angle. Collectively, these results provide a theoretical basis to guide future designing of explosion pressure relief outlet angles in a restricted space. [ABSTRACT FROM AUTHOR]

In this paper, a kind of classic generalized Riemann problem for 2-dimensional isothermal Euler equations for compressible gas dynamics is considered. The problem is the gas (u 0 , v 0 , r 0 ∣ x ∣ β) in the rectangular region expands into the vacuum. We construct the solution of the following form u = u (ξ , η) , v = v (ξ , η) , ρ = t β ϱ (ξ , η) , ξ = x t , η = y t , where ρ and (u, v) denote the density and the velocity fields respectively, and u 0 , v 0 , r 0 > 0 and β ∈ (- 1 , 0) ∪ (0 , + ∞) are constants. The continuity of the self-similar solution depends on the value of β . Under certain conditions, we get a weak solution with shock wave, which is necessarily generated initially and move apart along a plane. Furthermore, by the method of characteristic analysis, we explain the mechanism of the shock wave. [ABSTRACT FROM AUTHOR]

Transfemoral (TF) access is the preferred approach for transcatheter aortic valve replacement (TAVR). Limited data exist regarding the outcomes of intravascular lithotripsy (IVL)-assisted TF TAVR in patients with peripheral artery disease. This study sought to examine contemporary characteristics, trends, and outcomes of IVL TAVR in the United States. The Vizient Clinical Database was queried for patients who underwent percutaneous TAVR between October 1, 2020, and November 30, 2023. Outcomes with IVL TAVR vs non–IVL TAVR were examined after propensity score matching. The primary outcome was a composite of in-hospital death, stroke, vascular complications, surgical vascular intervention, and major bleeding. Over the study period, 129,655 patients (mean age of 78.4 years, 42.2% women, 87.1% White) underwent percutaneous TAVR at 361 hospitals, 1,242 (0.96%) of whom underwent IVL TAVR. There was an uptrend in IVL TAVR, but the frequency remained low. IVL TAVR patients had a higher median Elixhauser comorbidity score (5 [Q1-Q3: 4-7] vs 4 [Q1-Q3: 3-6]) compared to non–IVL TAVR. TAVR was completed via the TF approach in 1,238 (99.7%) IVL TAVR patients. In a 3:1 propensity score matching analysis, IVL TAVR was associated with a higher rate of the primary composite outcome (21.9% vs 13.7%; P < 0.001) driven by higher rates of vascular complications, surgical vascular intervention, and major bleeding. In-hospital death and stroke were similar in both groups. In the United States, IVL is increasingly adopted to facilitate TF TAVR. IVL TAVR patients exhibited a higher burden of comorbidities and experienced more complications compared to non–IVL TAVR patients. Further studies are needed to identify appropriate anatomical and clinical use criteria for IVL TAVR and to compare its outcomes vs alternative non–TF TAVR. [Display omitted] [ABSTRACT FROM AUTHOR]

In a gas–water interaction problem, the nonlinear relationship between shock wave velocity is introduced into a Hugoniot curve, and a Mie–Grüneisen Equation of state (EOS) is established by setting the Hugoiot curve as the reference state. Unlike other simple EOS based on the thermodynamics laws of gas (such as the Tait EOS), the Mie–Grüneisen EOS uses reference states to cover an adiabatic impact relationship and considers the thermodynamics law separately. However, the expression of the EOS becomes complex, and it is not adaptive to many methods. A multicomponent Mie–Grüneisen mixture model is employed in this study to conquer the difficulty of the complex form of an EOS. In this model, some coefficients in the Mie–Grüneisen EOS are regarded as variables and solved using newly constructed equations. The performance of the Mie–Grüneisen mixture model in the gas–water problem is tested by low-compression cases and high-compression cases. According to these two tests, it is found that the numerical solutions of the shock wave under the Mie–Grüneisen EOS agrees with empirical data. When compared to other simple-form EOSs, it is seen that the Mie–Grüneisen EOS has slight advantages in the low-compression case, but it plays an important role in the high-compression case. The comparison results show that the solution of the simple-form EOS clearly disagrees with the empirical data. A further study shows that the gap between the Mie–Grüneisen EOS and other simple-form EOSs becomes larger as the initial pressure and particle velocity increase. The impact effects on the pressure, density and particle velocity are studied. Moreover, the gas–water interaction in a spherical coordinate plane and a two-dimensional coordinate is a significant part of our work. [ABSTRACT FROM AUTHOR]

In high-speed flow applications, increased aero-thermodynamic loads, localized turbulent regions, instability, excessive drag and pressure losses are among the negative effects of the interaction between shock waves and boundary layers and the subsequent separation of the boundary layer. These drawbacks emphasize how crucial it is to look into ways to control the boundary layer separation caused by shock waves. In order to determine whether using a pressure feedback technique to regulate boundary layer separation on a two-dimensional forward-facing step (FFS) is effective, a numerical study is conducted. The pressure feedback technique utilizes a channel to remove fluid from the separated area and reintroduce it into the mainstream flow, by leveraging the pressure contrast as the motivating factor. Ansys Fluent 2021 simulation software is used to conduct a numerical study investigating shock wave boundary layer interaction over a FFS at a supersonic Mach number of 2.5. The present study aims to explore the effectiveness of implementing a pressure feedback channel near the FFS as a strategy for controlling flow separation induced by the step. Turbulence effects are simulated using a k-omega model, and the study employs a finite-volume method with upwind flux difference splitting and second-order upwind flow discretization. The simulation results indicate the efficacy of the pressure feedback mechanism in reducing flow separation, thus enhancing its role in separation control. Integration of an 80mm channel results in a notable 42.85% decrease in separation bubble size, while the longer 90mm channel yields an even more substantial 52.38% reduction. [ABSTRACT FROM AUTHOR]

The issue of spontaneous ignition has become a bottleneck for hydrogen applications. This comprehensive review delves into the intricate mechanisms governing the spontaneous ignition of pressurized hydrogen released through tubes. Beginning with an exploration of fundamental concepts, including the properties of hydrogen and various theoretical frameworks, the study meticulously examines the development of diffusion ignition theory. Methodologically, both experimental and simulation approaches are scrutinized for their contributions to understanding this complex phenomenon. Moving deeper into the core of the investigation, the review dissects the spontaneous ignition mechanisms occurring inside pipes, unraveling the influence of different initial conditions as well as the impact of varying pipe structures. Subsequently, the review shifts its focus to the flame morphology at the pipe exit, analyzing combustion behavior, shock wave dynamics, flow structures, and the formation of jet flames, while exploring influential factors affecting combustion. Through a comprehensive synthesis of findings, this review provides valuable insights into the spontaneous ignition dynamics of pressurized hydrogen within tube systems, offering a foundation for future research and engineering applications in safety and energy sectors. • Introduced theories of self-ignition and development of diffusion ignition theory. • Summarized ignition mechanisms of pressurized hydrogen released inside pipes. • Summarized flame morphology at pipe exit based on vortex position. • Identified deficiencies in reviewed studies and areas needing further research. [ABSTRACT FROM AUTHOR]

The work studies scenarios of self-ignition of hydrogen-air mixtures after a shock wave reflects from a destructible barrier made of sand or a solid wall. The experiments were carried out using a shock tube. The transverse dimensions of the diagnostic section were 40 × 40 mm. The initial pressure of the hydrogen-air mixture varied from 10 kPa to 50 kPa. The molar excess of hydrogen (equivalence ratio) was 0.3, 0.4 and 0.5. Typical oscillograms of pressure, a photomultiplier tube, and the results of high-speed visualization using the Schlieren method are presented. When the shock wave interacted with the destructible barrier, a thermodynamic unloading of shock-compressed mixture occurred in the direction of the scattering of fragments of the barrier. It was shown that under certain conditions, self-ignition of hydrogen could be prevented by using a destructible barrier. In this case, the prevention was recorded in a narrow range of Mach numbers of the incident shock wave, which are characterized by the occurrence of the so-called "weak" (or "mild") ignition of the hydrogen-air mixture. The conditions for strong ignition behind the reflected shock wave, as well as during the interaction of the reflected shock wave with the flame front behind the incident shock wave, were determined. The results of the presented experimental work are aimed at ensuring explosion safety when working with hydrogen in a confined space. [Display omitted] • The interaction of a shock wave with a sand barrier was studied. • Scenarios for self-ignition behind a reflected shock wave were determined. • Self-ignition can be prevented by placing a sand barrier instead of a solid wall. • The pressure ratios were determined during self-ignition. [ABSTRACT FROM AUTHOR]

The Mach number effect on the Richtmyer–Meshkov instability (RMI) evolution of the shocked V-shaped N 2 / SF 6 interface is numerically studied in this research. Four distinct Mach numbers are taken into consideration for this purpose: M s = 1.12 , 1.22 , 1.42 , and 1.62. A two-dimensional space of compressible two-component Euler equations is simulated using a high-order modal discontinuous Galerkin approach to computational simulations. The numerical results show good consistency when compared to the available experimental data. The computational results show that the RMI evolution in the shocked V-shaped N 2 / SF 6 interface is critically dependent on the Mach number. The flow field, interface deformation, intricate wave patterns, inward jet development, and vorticity generation are all strongly impacted by the shock Mach number. As the Mach number increases, the V-shaped interface deforms differently, and the distance between the Mach stem and the triple points varies depending on the Mach number. Compared to lower Mach numbers, higher ones produce larger rolled-up vortex chains. A thorough analysis of the Mach number effect identifies the factors that propel the creation of vorticity during the interaction phase. Moreover, kinetic energy and enstrophy both dramatically rise with increasing Mach number. Lastly, a detailed analysis is carried out to determine how the Mach number affects the temporal variations in the V-shaped interface's features. [ABSTRACT FROM AUTHOR]

This paper investigates numerically the shock wave interaction with a V-shaped heavy/light interface. For numerical simulations, we choose six distinct vertex angles ( θ = 40 ∘ , 60 ∘ , 90 ∘ , 120 ∘ , 150 ∘ , and 170 ∘) , five distinct shock wave strengths ( M s = 1.12 , 1.22 , 1.30 , 1.60 , and 2.0 ), and three different Atwood numbers ( A t = − 0.32 , − 0.77 , and − 0.87 ). A two-dimensional space of compressible two-component Euler equations are solved using a third-order modal discontinuous Galerkin approach for the simulations. The present findings demonstrate that the vertex angle has a crucial influence on the shock wave interaction with the V-shaped heavy/light interface. The vertex angle significantly affects the flow field, interface deformation, wave patterns, spike generation, and vorticity production. As the vertex angle decreases, the vorticity production becomes more dominant. A thorough analysis of the vertex angle effect identifies the factors that propel the creation of vorticity during the interaction phase. Notably, smaller vertex angles lead to stronger vorticity generation due to a steeper density gradient, while larger angles result in weaker, more dispersed vorticity and a less complex interaction. Moreover, kinetic energy and enstrophy both dramatically rise with decreasing vortex angles. A detailed analysis is also carried out to analyze the vertex angle effects on the temporal variations of interface features. Finally, the impacts of different Mach and Atwood numbers on the V-shaped interface are briefly presented. [ABSTRACT FROM AUTHOR]

High voltage electric pulse (HVEP) was used to perform concrete cracking experiments to demonstrate the feasibility of this technique for cracking hard objects. The results of the study show that HVEP fracturing technology has great potential for application. This article uses a high-speed camera to record the crack expansion process, and analyze the relationship between crack expansion speed and time. The Hilbert–Huang Transform (HHT) is used to analyze the vibration signal generated by the shock waves (SWs). The energy evolution law of SWs is elaborated by the time–frequency characteristics of the vibration. The distribution of the vibration energy is more concentrated between 0 and 100 Hz. The increase of capacitance value will produce stronger vibration peak energy and force. The presence of cracks will cause the vibration energy propagation to be blocked and the energy decay rate to be accelerated. Also, the energy will be shifted in the frequency domain due to the presence of cracks. Highlights: A high-power high voltage electric pulse fracturing equipment is designed and manufactured. The process of crack formation and expansion is recorded. Hilbert–Huang transform analysis of the time–frequency characteristics of vibration signals. Increase of capacitance enhances instantaneous energy and maximum force of discharge. Cracks cause the energy decay of shock waves to become faster. [ABSTRACT FROM AUTHOR]

Incorporating nano-particles into polymer matrix has enabled improving shock wave mitigation (SWM) ability. Vast majority of researchers adopted inorganic nano-materials to enhance polymer matrix. Due to the incompatibility between inorganic nano-particles and polymers, complicated interface modification processes were often used. Metal–organic frameworks (MOFs) have good compatibility with polymers and show excellent SWM capabilities. However, they are brittle and experience lattice collapse after shock loading. Based on this, thermoplastic polyurethane (TPU) enhanced by zeolitic imidazolate framework-8 (ZIF-8) was proposed and prepared. The mixtures can not only improve the SWM ability of polymers, but also address the brittleness of MOFs. Additionally, scholars often use simulation methods to study energy dissipation mechanism of materials, rarely evidences of microstructural changes observed to support theoretical speculations. In this work, by analyzing surface morphology and molecular structural changes, energy dissipative mechanism was investigated. With addition amount of 5 wt% and 10 wt% ZIF-8 particles in TPU, the pressure can be reduced by 0.074 GPa and 0.1478 GPa than neat TPU. TPUM-10 had a stronger deformation resistance and SWM ability. Moreover, main chemical structures were remained unchanged after shock. The increased ability of SWM may relate to hydrogen bond forming process and delayed material failure. [ABSTRACT FROM AUTHOR]

The pressure-time relation in the shock flow field of a near-earth air blast is complex. The triple point (TP) path is the physical boundary between the free and non-free shock flow fields. Accurately predicting the TP path is the basis for studying the evolution law of the reflection flow field and the guarantee of effectively assessing the damage power of the warhead. Based on the assumption that the Mach stem center is on the projection point of the blast center on the ground, the TP path calculation method was constructed by the geometric relationship. The unknown coefficients were solved using the existing TP data and the least square method. The TP prediction model proposed was compared with the existing ones on the calibration, new numerical simulation TP, and the measured real blast datasets. The error of the new numerical simulation TP data is within ±15% of the real value. The results show that the TP path prediction model proposed performs better. Most of its prediction results are within ±20% of three datasets compared to other models for the working conditions with the scaled height of burst from 0.397 to 2.777 m/kg1/3 and the horizontal scaled distance within 10 m/kg1/3 in the conventional cylindrical TNT explosion with the length-diameter of 1 in the air. The reliability of the prediction model is verified. [ABSTRACT FROM AUTHOR]

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

Copyright of Journal of Ordnance Equipment Engineering is the property of Chongqing University of Technology 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.)

Forward-swept wings were researched and introduced to improve maneuverability, control, and fuel efficiency while reducing drag and they are often used alongside canards, to further enhance their characteristics. In this research, the effects of canard dihedral angles on the wing loading of a forward-swept wing in transonic flow conditions were studied, as the wing loading provides a measure of wing's efficiency (lift/drag). A generic aircraft model from literatures was selected, simulated, and compared to, using CFD software ANSYS/Fluent where the flow equations were solved to calculate the aerodynamic characteristics. The research was carried at two different Mach numbers, 0.6 and 0.9, for five different canard dihedral angles which traverses from below the wing plane to above it, at various flow angles of attack. It was concluded that as the dihedral angle increased, lift increases for the same angle of attack for Mach 0.6 and 0.9 which increases the efficiency of the wing. The wing span loading occur at 10° dihedral angle for both Mach speeds, while, at 10° anhedral, the lift was minimal due to leading-edge flow separation on the FSW's lower surface. Thus, it is concluded that the canard at positive dihedral angles ensures increased wing span loading efficiency. [ABSTRACT FROM AUTHOR]

To alleviate the shock boundary layer interaction adverse effects, various active or passive flow control strategies have been investigated in the literature. This research sheds light on the behavior of perforated plates as passive flow control techniques applied to NACA0012 airfoils in cascade configurations. Two identical perforated plates with shallow cavities underneath are accommodated on the upper and lower surfaces of each airfoil in the cascade arrangement. Six different cascade arrangements, including a baseline configuration with no control applied, are additively manufactured, with different perforated plate orifice sizes in the range of 0.5–1.2 mm. A high-speed wind tunnel with Schlieren optical diagnosis and wall static pressure taps is used to investigate the changes in the shock waves pattern triggered by the perforated plates. Steady 3D density-based numerical simulations in Ansys FLUENT are conducted for further analysis and validation. In the cascade configuration, the perforated plates alter the shock structure, and the strong normal shock wave is replaced by a weaker X-type shock structure. Eventually, a 1% penalty in overall total pressure loss is induced by the perforated plates because of the negative loss balance between the reduced shock losses and the enhanced viscous losses. Further studies on perforated plate geometrical features are needed to improve this outcome in a cascade arrangement. [ABSTRACT FROM AUTHOR]

In this work, we have studied the propagation of nonlinear electrostatic shock waves in an anisotropically pressured magnetized plasma containing positive and negative ions, trapped electrons, and positrons. A reductive perturbation technique is used to generate the trapped Zakharov-Kuznetsov Burgers' equation is generated for nonlinear analysis. We study and debate the effects of positron and electron trapping on shock structures. In addition, the influence of an external magnetic field and an anisotropic pressure on the shock waves for both positive and negative ions is thoroughly discussed. It is shown that the amplitude and magnitude of the shock wave are affected by changes in the bulk viscosity and kinematic viscosity for both ions. The paper examines the unique characteristics of rarefactive shock-like formations under various plasma conditions, including ion bulk and kinematic viscosities, electrons and positron trapping with the influence of magnetic fields. This result of this study will provide a better understanding of the nonlinear transmission of ion acoustic shock waves in astrophysical environments, such as neutron stars and pulsar magnetospheres. [ABSTRACT FROM AUTHOR]

A numerical simulation of an unsteady gas flow containing inert solid particles in a shock tube is carried out using the interpenetrating continuum model. The gas and dispersed phases are characterized by governing equations that express the concepts of mass, momentum, and energy conservation as well as an equation that shows the change of the volume fraction of the dispersed phase. Using a Godunov-type approach, the hyperbolic governing equations are solved numerically with an increased order of accuracy. The working section of the shock tube containing air and solid particles of various sizes is considered. The shock wave structure is discussed and computational results provide the spatial and temporal dependencies of the particle concentration and other flow quantities. The numerical simulation results are compared with available experimental and computational data. [ABSTRACT FROM AUTHOR]

The growing demand for increasing the engine power of a liquid rocket is driving the development of high-power De-Laval nozzles, which is primarily achieved by increasing the expansion ratio. A high-expansion-ratio for De-Laval nozzles can cause flow separation, resulting in unsteady, asymmetric forces that can limit nozzle life. To enhance nozzle performance, various separation control methods have been proposed, but no methods have been fully implemented thus far due to the uncertainties associated with simulating flow phenomena. A numerical study of a high-area-ratio rocket engine is performed to analyze the aeroelastic performance of its structure under flow separation conditions. Based on numerical methodology, the flow inside a rocket nozzle (the VOLVO S1) is analyzed, and different separation patterns are comprehensively discussed, including both free shock separation (FSS) and restricted shock separation (RSS). Since the location of the flow separation point strongly depends on the turbulence model, both the single transport equation and two-transport-equation turbulence models are simulated, and the findings are compared with the experimental results. Therefore, the Spalart–Allmaras (SA) turbulence model is the ideal choice for this rocket nozzle geometry. A wavelet is used to analyze the amplitude frequencies from 0 to 100 Hz under various pressure fluctuation conditions. Based on a clear understanding of the flow field, an aeroelastic coupling method is carried out with loosely coupled computational fluid dynamics (CFD)/computational structural dynamics (CSD). Some insights into the aeroelasticity of the nozzle under separated flow conditions are obtained. The simulation results show the significant impact of the structural response on the inherent pressure pulsation characteristics resulting from flow separation. [ABSTRACT FROM AUTHOR]

This research aims to experimentally characterize cooling, clogging and jamming of a dry granular flow in a chute partially obstructed by a stopping wall with two slits adjacent to the side walls. We ensemble‐average velocities, determined with Particle Tracking Velocimetry, and its fluctuations, to compute mean flow and granular temperature fields. Full chute‐wide jamming is triggered by the formation of stable arch‐like clogging structures in front of the slits. The statistical distribution of the clogging instant is not heavy‐tailed, which indicates that clogging occurs only when the flow through the slits is liquid‐like. An upstream‐progressing jamming wave eventually forms, similar to that observed in fully obstructed chutes. There is no triple point anywhere, since the flow cools down to a granular liquid before jamming. We identified three main stages of jamming wave propagation. The initial buildup is characterized by high values of the upstream Froude number, slow progression, and transformation of kinetic into potential energy. This occurs with significant granular head losses, as particles attempt to flow over the jam. In the second stage, accretion becomes dominant, characterized by smaller head losses and, consequently, higher values of the jamming wave celerity. In the third stage, the jamming wave propagates against a cooler but faster flow that pushes against the jam, slightly increasing the wave strength. Accretion is the main mechanism of jammed mass increase, justifying a further increase of wave acceleration. The macroscopic aspects of the jamming wave dynamics can be described, as a first approximation, by shallow‐water theory. Key Points: The flow through the slits enters the clogging regime as it cools down. Chute‐wide generalized jamming results from cloggingThere are no triple points in the system. Jamming only incorporates particles that have cooled to liquid‐like behaviorThe dynamics of the jamming wave exhibit three stages, with different roles of accretion and upward dissipative modes of jamming [ABSTRACT FROM AUTHOR]

Abstract Nuclear explosion in a densely populated area is the worst that can happen to any country in the world due to enormous loss of life, property and severe economic damage. Nuclear explosions immediately cause radiological damage and destruction of infrastructure. This hydro-magnetic shock propagation due to blast gives rise to simultaneous signals around the world. The effect of shockwave from nuclear explosion is an area that can be used to handle post and pre-disaster from nuclear explosion. This study focuses on the effects of shockwave on solid objects oriented in different formation. Experiments conducted in a horizontally placed shock tube and a solid object holder on the floor of the test section. These solid objects placed inside the test section of a shock tube collided with a planner shock wave which was generated by rupturing a diaphragm of different thickness. Four high speed pressure transducers strategically placed at different locations of this shock tube were used to characterize the blasts as well as interaction with the samples. A high-speed Kronos and Phantom camera were used to record the exact moment of interaction to characterize the solid objects under the impact of different shock waves. Representative results of these experiments are reported here along with review of previous work done in this area.

Abstract Gas has been widely concerned due to its importance in the industrial and energy fields. In order to improve the inhibition effect of gas explosion, under the self-constructed pipe network system, the inhibition of gas explosion by composite inhibitor of fly ash and NaHCO3 with different ratios was investigated, and the microscopic inhibition mechanism of the two kinds of powders on the explosion of gas was investigated based on the method of density functional theory and transition state theory from the perspective of molecular dynamics. The results show that: the composite powder explosion suppression is better than a single powder, explosion suppression effect with the increase in the proportion of the mass of NaHCO3 significantly improve the 5 groups of conditions NaHCO3 loading of 40% (by mass) is the best, this time, the explosion of the peak overpressure, the peak flame propagation velocity, the peak flame temperature compared to the maximum reduction in the percentage of the measures taken for the maximum of 74.42%, 81.93%, 68.71%. In addition, NaHCO3, fly ash effectively inhibit the key primitive reaction of gas explosion. When the temperature reaches a certain point, the two and O*, O2, OH* and H* reaction rate higher than the rate of CH4 oxidation chain reaction, the dominant reaction, the maximum difference in rate constants of 70.95, 58.81, 60.06, 44.94. The study of the transition from the macro-scale to the molecular level of the study, in-depth understanding of the mechanism of explosion suppression, to reduce the risk of explosion from the ground up, and enriches the Gas explosion prevention and control of the theoretical system, for the operators to provide a strong technical guarantee for safe production.

BACKGROUND: Flap transplantation technique is a commonly used surgical procedure for the treatment of severe tissue defects, but postoperative flap necrosis is easily triggered by ischemia-reperfusion injury. Therefore, it is still an important research topic to improve the survival rate of transplanted flaps. OBJECTIVE: To review the pathogenesis and latest treatment progress of flap ischemia-reperfusion injury. METHODS: CNKI, WanFang Database and PubMed database were searched for relevant literature published from 2014 to 2024. The search terms used were “flap, ischemia-reperfusion injury, inflammatory response, oxidative stress, Ca2+ overload, apoptosis, mesenchymal stem cells, platelet-rich plasma, signaling pathways, shock wave, pretreatment” in Chinese and English. After elimination of irrelevant literature, poor quality and obsolete literature, 77 documents were finally included for review. RESULTS AND CONCLUSION: Flap ischemia/reperfusion injury may be related to pathological factors such as inflammatory response, oxidative stress response, Ca2+ overload, and apoptosis, which can cause apoptosis of vascular endothelial cells, vascular damage and microcirculation disorders in the flap, and eventually lead to flap necrosis. Studies have found that mesenchymal stem cell transplantation, platelet-rich plasma, signaling pathway modulators, shock waves, and pretreatment can alleviate flap ischemia/reperfusion injuries from different aspects and to varying degrees, and reduce the necrosis rate and necrosis area of the grafted flap. Although there are many therapeutic methods for skin flap ischemia/reperfusion injury, a unified and effective therapeutic method has not yet been developed in the clinic, and the advantages and disadvantages of various therapeutic methods have not yet been compared. Most of the studies remain in the stage of animal experiments, rarely involving clinical observations. Therefore, a lot of research is required in the future to gradually move from animal experiments to the clinic in order to better serve the clinic. [ABSTRACT FROM AUTHOR]

A separation experiment of polystyrene microspheres in water based on tapered fiber pulsed laser system was carried out. We analyzed the motion images during the separation of polystyrene microsphere clusters and investigated the influence of laser energy and initial cluster positions on the separation results. Through the study of bubbles generated by pulsed laser separation of microsphere clusters, we summarized the process of micron-sized bubble formation and the factors contributing to their prolonged existence. Additionally, we clarified the separation mechanism of microsphere clusters. The results indicate that as the laser energy increases, the separation effect of microsphere clusters improves from 151 μ m to 170 μ m. When the laser energy is 50.1 μ J, a more significant initial distance leads to weaker separation effects. Furthermore, the diameter of micron-sized bubbles is positively correlated with separation effects. [ABSTRACT FROM AUTHOR]

In modern technologies of pneumatic transport, fluidization, and polymer spraying, gas-dispersed media are widely used. Of particular interest, from the point of view of dynamic loading of structures, are shock-wave processes in gas-dispersed mixtures in the vicinity of the walls. The use of computer modeling methods makes it possible to reduce time and material costs for improving designs and optimizing technological process parameters. A hybrid large-particle method of second order approximation with a nonlinear correction, Superbee at the Eulerian stage and VanLeer at the Lagrangian stage, was used for the calculations. The algorithm is implemented as multi-threaded solver code, with processing of graphical results in a separate parallel process. A detailed numerical simulation of the characteristic stages of the interaction of a shock wave with a wall shielded by a layer of finely dispersed gas suspension with a cylindrical region of increased particle density was carried out. The beginning of the process (before the interaction of a plane shock wave passing into the layer of gas suspension with inhomogeneity) is one-dimensional in nature. Further development of the physical picture is associated with a significant restructuring of the flow. The shock wave enveloping the cylindrical boundary of the inhomogeneity converges to the plane of symmetry with the formation of a focusing effect. Due to baroclinic instability (mismatch of pressure and density gradients), a vortex zone is formed on the surface of the highdensity boundary. As shown by a detailed analysis of the calculation results, the most significant (more than an order of magnitude relative to the initial state) surges in pressure and density of the gas suspension are caused by the interactions of a focused shock wave that has passed into the inhomogeneity, and then an incident reflected composite shock wave pulse. The results obtained have theoretical and applied significance. New physical effects of shock wave reflection from a wall shielded by a layer of gas suspension with a cylindrical region of increased density of the dispersed fraction have been revealed. The reasons for the sequence of bursts in pressure and density of the mixture, which can lead to ignition and detonation of the combustible dispersed phase, are determined. The developed numerical algorithm and computer modeling technique can form the basis for the analysis of shock wave phenomena in the vicinity of the walls of structures and the justification of rational parameters of technological gas-powder technologies.

The shock wave boundary layer interaction (SWBLI) due to curved shock is studied prominently, as most military aircrafts and missiles undergo strong SWTBLI due to its curved or blunt shape. These interactions effect the performance of vehicles at supersonic flow regime. The present numerical study investigates, interaction between a shock wave and turbulent boundary layer (SWTBLI) for cylindrical shock generators at freestream Mach number 3. The diameter (D) of cylindrical shock generator is varied to determine the effect of strength of shock on boundary layer and effect on impinging location from leading edge of flat plate, which depends upon the position of cylindrical shock generator. Two dimensional numerical simulations are carried out on mentioned model using commercially available CFD solver that employs k-omega SST turbulence model. Computational results show a good agreement qualitatively in terms of separation location and separation bubble length and quantitatively predicts the surface pressure, accurately as compared to the experiments conducted by literature.

Abstract In the field of power ultrasonic vibration processing, the thin liquid layer nestled between the tool head and the material serves as a hotbed for cavitation shock wave emissions that significantly affect the material's surface. The precise manipulation of these emissions presents a formidable challenge, stemming from a historical deficit in the quantitative analysis of both the ultrasonic enhancement effect and the shock wave intensity within this niche environment. Our study addresses this gap by innovatively modifying the Gilmore-Akulichev equation, laying the groundwork for a sophisticated bubble dynamics model and a pioneering shock wave propagation model tailored to the thin liquid layer domain. Firstly, our study investigated the ultrasound enhancement effect under various parameters of thin liquid layers, revealing an amplification of ultrasound pressure in the thin liquid layer area by up to 7.47 times. The mathematical model was solved using the sixth-order Runge–Kutta method to examine shock wave velocity and pressure under different conditions. our study identified that geometric parameters of the tool head, thin liquid layer thickness, ultrasonic frequency, and initial bubble radius all significantly influenced shock wave emission. At an ultrasonic frequency of 60 kHz, the shock wave pressure at the measurement point exhibited a brief decrease from 182.6 to 179.5 MPa during an increase. Furthermore, rapid attenuation of the shock wave was found within the range of R 0-3R 0 from the bubble wall. This research model aims to enhance power ultrasonic vibration processing technology, and provide theoretical support for applications in related fields.

This paper presents an analytical investigation into the propagation of a normal shock wave in Van der Waals gas flow, employing the Buongiorno model. It explores the dynamics of this flow type under a shock wave, considering modified Rankine–Hugoniot (RH) jump conditions within the Buongiorno model framework. By solving the RH conditions, this study provides a solution for gas flows with varying nanoparticle concentrations, facilitating an examination of parameter variations under discontinuity. The abstract further emphasizes the graphical representation of velocity coefficient and pressure in adiabatic gas flow during a shock wave, considering compressive and exponential waves. The analysis accounts for nanoparticle concentration and non-ideal parameters. [ABSTRACT FROM AUTHOR]

In the study of self-ignition during pressurized hydrogen release, the morphology of the rupture disk alters the flow and mixing processes of the gas jet, as well as the development of shock waves, thereby affecting the occurrence of self-ignition. This study employs the LES method based on the RNG-SGS model, EDC model, and NUIMech1.1 H 2 combustion mechanism to investigate the flow mixing, shock wave development, and self-ignition phenomena under three different the rupture disk morphologies. The research findings indicate that as the growth trend of the rupture disk rupture ratio increases, the propagation speed of shock waves within the tube and the compression speed of the air and hydrogen-air mixing region accelerate, resulting in an earlier occurrence of self-ignition. A more complex rupture morphology leads to higher mixing rates between hydrogen and air and increased complexity of shock waves. Self-ignition initially occurs in the fuel-lean region of the boundary layer, followed by ignition at the center of the tube. The characteristic number of rupture disk is proposed to describe its impact on the self-ignition time. The competitive relationship between the two elementary reaction pathways of oxygen influences the development of the flame. • A CFD model for hydrogen release and self-ignition is established and validated. • The development process of multidimensional shock waves is described in detail. • The process of self-ignition and entire flame development is fully captured. • The reaction mechanism and HRR of self-ignition are analyzed. • The impact of rapture disk morphology on flow and self-ignition is fully obtained. [ABSTRACT FROM AUTHOR]

The rapid, energy‐efficient, scalable preparation of high‐strength, flexible, multifunctional nanostructured aerogels is highly desired yet challenging. Here, an ambient‐pressure‐dried (APD) strategy is developed involving self‐foaming, dip‐coating, and graphene oxide (GO)‐assisted multiple cross‐linking treatments for the prompt, large‐area preparation of polyurea/transition metal carbides/nitrides (MXenes) aerogels. The APD MXene‐based aerogels showcase low density, remarkable mechanical strength, and ultraflexiblity involving stretchability, good conductivity, hydrophobicity, and high resistance to various solvents. Synergies of robust, elastic cell walls and porous structure contribute to high‐efficiency absorption of high‐frequency, high‐speed mechanical shock waves for the aerogels, significantly transcendinging the biomasses, plastics, elastomers, ceramics, and metals. In addition to the excellent microwave shielding performance of over 40 dB in ultrabroadband frequencies of 4–40 GHz, the oxidation stability is elevated for APD MXene aerogels, consequently yielding applicability in harsh conditions. Furthermore, the superior light absorption capability of aerogels leads to the efficient photothermal conversion, therapy, antibacterial, desalination, water purification, deicing, and thick oil absorption. This work provides a facile, time‐ and energy‐efficient, scalable APD methodology for manufacturing large‐area, high‐strength, ultraflexible, multifunctional MXene‐based aerogels, enlighting a novel synergistic defense against mechanical shock and electromagnetic waves, and promoting them as a prospective candidate in aerospace, device protection, and next‐generation electronics. [ABSTRACT FROM AUTHOR]

This paper deals with CFD analyses of the difference in the nature of the shock waves in supersonic flow under atmospheric pressure and pressure conditions at the boundary of continuum mechanics for electron microscopy. The first part describes the verification of the CFD analyses in combination with the experimental chamber results and the initial analyses using optical methods at low pressures on the boundary of continuum mechanics that were performed. The second part describes the analyses on an underexpanded nozzle performed to analyze the characteristics of normal shock waves in a pressure range from atmospheric pressure to pressures at the boundary of continuum mechanics. The results obtained by CFD modeling are prepared as a basis for the design of the planned experimental sensing of density gradients using optical methods, and for validation, the expected pressure and temperature courses from selected locations suitable for the placement of temperature and pressure sensors are prepared from the CFD analyses. [ABSTRACT FROM AUTHOR]

To analyze the influence of different ignition positions on the propagation of deflagration characteristics and the disaster mechanism in the hydrogen deflagration process in the tunnel, this study compares and verifies the experimental data of tunnel model deflagration based on the CFD code GASFLOW-MPI. A combustion velocity model based on the accelerated separation effect is used, and the effect of heat transfer on the consequences of deflagration is considered. The propagation laws of pressure waves, fluid velocity and temperature in the tunnel are analyzed, and it is found that the changing trends of shock waves and fluid velocity in the tunnel are consistent, but completely opposite in the tunnel outside. The effects of different ignition positions on the hydrogen deflagration characteristics are compared and analyzed. The results show that when ignition occurs at different heights of the center of the premixed region, the impact on the deflagration characteristics is relatively small, while when ignition occurs at different horizontal distances in the premixed region, the impact on the deflagration characteristics is relatively large; the peak overpressure of side ignition is far lower than the case where ignition occurs in the center of the premixed region, but the maximum flow velocity is much higher than the center ignition. The impact on temperature is the smallest. In general, in areas close to the hydrogen/air premixed zone, side ignition results in more severe consequences, whereas in areas far from the premixed zone and outside the tunnel, central ignition leads to more severe consequences. This study provides theoretical support for understanding the disaster-causing mechanisms of hydrogen/air premixed gas deflagration in tunnels under different ignition positions. • Deflagration behaviors of hydrogen-air mixtures in the tunnel were studied. • Heat transfer and flame instability are taken into account in numerical simulations. • The deflagration consequences of different ignition positions are discussed. • Side ignition causes the least peak overpressure in the tunnel. [ABSTRACT FROM AUTHOR]

Molecular dynamics study of the influence of phase distribution on the response of two-phase nanocrystalline Fe95Ni05 samples with a gradient grained structure under shock loading was carried out. It was shown that the propagation of a shock wave causes direct and reverse FCC-BCC-FCC phase transformations in grains with the FCC structure, BCC-FCC/HCP phase transformations in lamellas with the BCC structure, as well as the nucleation of the HCP phase. The shock wave and the wave reflected from the rear surface initiated transformation of a significant part of the sample into the HCP phase. Shock wave propagation in the sample caused the appearance of two maxima on the curve of the time dependence of the HCP phase volume fraction. Time changes in the HCP phase fraction correlated with changes in the fraction of atoms belonging to intrinsic stacking faults and the dislocation density in the FCC phase. A large volume fraction of the intrinsic stacking faults, a higher dislocation density, and a lower volume fraction of the HCP phase were observed in the case of the sample with BCC lamellas only in one layer of grains compared to the sample with BCC lamellas in all grains under shock loading. [ABSTRACT FROM AUTHOR]

The non-equilibrium characteristics during the shock relaxation process hold a foundational position in various fields. In contrast to the propagation of a single shock wave, the collision process of two shock waves exhibits distinct non-equilibrium features. Employing non-equilibrium molecular dynamics, we simulated the collision of ultra-strong shock waves in a classical gas system, investigating the relationship between equilibrium relaxation time and shock intensity. Tracking the spatial migration of microscopic particles in the shock collision region during the relaxation process, we observed a significant contribution of particle migration to the average energy changes during relaxation. The discussion on particle migration provides a valuable new perspective for understanding the microscopic mechanisms of the relaxation process. [ABSTRACT FROM AUTHOR]

Extracellular vesicles (EVs) have emerged as a potential delivery vehicle for nucleic‐acid‐based therapeutics, but challenges related to their large‐scale production and cargo‐loading efficiency have limited their therapeutic potential. To address these issues, we developed a novel "shock wave extracellular vesicles engineering technology" (SWEET) as a non‐genetic, scalable manufacturing strategy that uses shock waves (SWs) to encapsulate siRNAs in EVs. Here, we describe the use of the SWEET platform to load large quantities of KRASG12C‐targeting siRNA into small bovine‐milk‐derived EVs (sBMEVs), with high efficiency. The siRNA‐loaded sBMEVs effectively silenced oncogenic KRASG12C expression in cancer cells; they inhibited tumour growth when administered intravenously in a non‐small cell lung cancer xenograft mouse model. Our study demonstrates the potential for the SWEET platform to serve as a novel method that allows large‐scale production of cargo‐loaded EVs for use in a wide range of therapeutic applications. [ABSTRACT FROM AUTHOR]

Results of spectroscopic measurements of the equilibrium electron concentration behind a strong shock wave in argon at a shock-wave velocity of 4.2 km/s and a pressure ahead of the wave front of 5 Torr and in O2, N2, and air in the velocity range from 8.3 to 11.3 km/s at an initial pressure of 0.25 Torr are presented. The measurement method was based on an analysis of broadening of the hydrogen-atom Hβ line of the Balmer series in the spectrum of the integral radiation density of the studied gas to which a small amount of H2 was added (~1%). The dependence of the electron concentration on the shock-wave velocity in O2, N2, and air was established. The results were compared with available experimental and calculated data. [ABSTRACT FROM AUTHOR]

In this study, a simulation and test-based procedure is created and applied to develop mechanical pyroshock test setup. In order to build an effective design, preliminary input parameters are defined with finite element simulations. The agreement between impact simulations and experimental data was achieved for resonant plate, metallic anvil plate and gun system. The obtained Shock Response Spectrum (SRS) curves are not well fitted to explicit finite element simulations for nonmetallic anvil plate materials, such as felt, which also have significant contribution to results. Therefore, further improvement is established by using test-based Response Surface Method (RSM). After validating the relationship statistically, response optimizer was used to find the best combination of design parameters to achieve target SRS curve. Finally, the prediction was checked experimentally to show the effectiveness of the developed methodology. [ABSTRACT FROM AUTHOR]

Introduction Musculoskeletal (MSK) injury is an inherent risk for military personnel that can potentially impact job performance, productivity, and military readiness. Evidence is needed to show the efficacy of nonpharmacological, self-managed therapies to reduce MSK symptoms at common injury sites that are feasible for use during expeditionary operations and home stations. This systematic review and meta-analysis identified, summarized, and synthesized available evidence from randomized and non‐randomized trials on the effectiveness of self-managed, home-use therapies to improve pain, muscle strength, and physical performance in military personnel with MSK injuries, when compared to controls. Methods The electronic databases of MEDLINE ALL Ovid, Embase.com, Cochrane Library, Scopus, Clinicaltrial.gov, and CINAHL Complete via EBSCO were systematically searched for relevant reports published in English. Utilizing the Covidence platform and consistent with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, multiple reviewers, using pre-determined data fields, screened for eligibility, assessed risk of bias (RoB), and performed data extraction. Evaluation of treatment effectiveness was determined using multilevel mixed-effects meta-analysis. Results The database and register search yielded 1,643 reports that were screened for eligibility. After screening of titles/abstracts and full texts, 21 reports were identified for evidence synthesis. Of these, two reports were excluded and two described the same study, resulting in a final list of 18 studies (19 reports). For quality assessment, the overall RoB for the 18 studies was categorized as 33.3% low risk, 55.6% with some concerns, and 11.1% high risk. Across the five domains of bias, 70% of the reports were classified as low risk. This systematic review found that the differences in interventions, outcome measures, and design between the studies were associated with a substantial degree of heterogeneity (I2 = 60.74%), with a small overall improvement in outcomes of the interventions relative to their specific control (standard mean difference 0.28; 95% CI, 0.12 to 0.45). There were varying degrees of heterogeneity for individual body regions. This was due, in part, to a small number of studies per bodily location and differences in the study designs. For the neck/shoulder, heterogeneity was moderate, with the clearest positive effect being for physical performance outcomes via other medical devices. For the back, there was substantial heterogeneity between studies, with modest evidence that pain was favorably improved by other medical devices and exercise interventions. For the leg, one study showed a clear large effect for other medical devices (shockwave treatment) on pain with substantial heterogeneity. The best evidence for positive effects was for the knee, with mainly negligible heterogeneity and some benefits from bracing, electrotherapy, and exercise. Conclusion Evidence showed small beneficial effects in pain, strength, and physical performance by individual body regions for some interventions, compared to controls. The best evidence for a positive effect was for the knee. The findings suggest that some benefit may be obtained by including several treatments during deployment in austere environments and prolonged casualty care scenarios of military personnel with MSK injuries. Further research is warranted to better assess the potential benefits of using these treatments during deployments in austere environments as part of an individualized, multimodal approach for MSK injuries. [ABSTRACT FROM AUTHOR]