Distribution Regularity of Muzzle Shock-Wave Inside Protective Cover

The injury of gunners caused by muzzle shock-wave has always been a great problem when firing inside the protective cover. The distribution regularity and personnel injury from the muzzle blast-wave were investigated by both test and numerical simulation. Through the inside firing test, the changes of overpressure and noise have been measured at different measuring points in the thin-wall cover structure with different open widths and shallow covering thickness. The distribution regularity of muzzle shock-wave with different firing port widths is calculated by ANSYS/LSDYNA software. The overpressure distribution curves of muzzle shock-wave inside the structure can be obtained by comparing the test results with the numerical results. Then, the influence of open width and shallow covering thickness is proposed to give a reference to the protective design under the condition of the inside firing with the same cannon caliber.

Shock-wave impact on the knee joint affected with osteoarthritis and after arthroplasty

Degenerative diseases significantly reduce the quality of human life.Non-invasive treatments are used in the initial stages of osteoarthritis(OA).Total knee arthroplasty is used in the late stages of osteoarthritis of the knee joint.Non-invasive methods based on mechanical action are also used for the rehabilitation of a patient after arthroplasty.This paper presents numerical models of the knee joint with degenerative OA changes and arthroplasty.Using these models,a computational study was made of the influence of the intensity of shock-wave exposure on the conditioning for the regeneration of bone and cartilage tissues.Based on the modeling results,it was found that in the knee joint with degenerative OA changes,conditions for the regeneration of cartilage and meniscus tissues were fulfilled under medium and highintensity loading.Under high-intensity loading(up to 0.9 m J/mm^(2)),the stress level was significantly below the ultimate value required for fracture.At knee arthroplasty,the conditions for bone tissue regeneration around the tibia component are fulfilled only under high-intensity loading.

Quantum Electrostatic Shock-Waves in Symmetric Pair-Plasmas

In this paper, the quantum hydrodynamics (QHD) model is used to study the propagation of small- but finite-amplitude quantum electrostatic shock-wave in an inertial-less symmetric pair (ion) plasma with immobile background positive constituents. The dispersion due to the quantum tunneling and inertial effects as well as dissipation caused by particle collisions leading to the shock-like or double-layer structures are considered. Investigation of both the stationary and traveling-wave solutions to Kortewege-de Veries-Burgers evolution equation show that critical values exist which govern the type of collective plasma structures. Current analysis apply to diverse kind of symmetric plasmas such as laboratory inertially confined or astrophysical pair-ion or electron-positron degenerate plasmas.

Experimental and Numerical Investigations of Shock-Wave Boundary Layer Interactions in a Highly Loaded Transonic Compressor Cascade

Experimental and numerical investigations were conducted to investigate the variations of shock-wave boundary layer interaction(SBLI) phenomena in a highly loaded transonic compressor cascade with Mach numbers.The schlieren technique was used to observe the shock structure in the cascade and the pressure tap method to measure the pressure distribution on the blade surface.The unsteady pressure distribution on blade surface was measured with the fast-response pressure-sensitive paint(PSP) technique to obtain the unsteady pressure distribution on the whole blade surface and to capture the shock oscillation characteristics caused by SBLI.In addition,the Reynolds Averaged Navier Stokes simulations were used to compute the three-dimensional steady flow field in the transonic cascade.It was found that the shock wave patterns and behaviors are affected evidently with the increase in incoming Mach number at the design flow angle,especially with the presence of the separation bubble caused by SBLI.The time-averaged pressure distribution on the blade surface measured by PSP technique showed a symmetric pressure filed at Mach numbers of 0.85,while the pressure field on the blade surface was an asymmetric one at Mach numbers of 0.90 and 0.95.The oscillation of the shock wave was closely with the flow separation bubble on the blade surface and could transverse over nearly one interval of the pressure taps.The oscillation of the shock wave may smear the pressure jump phenomenon measured by the pressure taps.

Structural uncertainty quantification of Reynolds-Averaged Navier–Stokes closures for various shock-wave/boundary layer interaction flows

Accurate prediction of Shock-Wave/Boundary Layer Interaction(SWBLI)flows has been a persistent challenge for linear eddy viscosity models.A major limitation lies in the isotropic representation of the Reynolds stress,as assumed under the Boussinesq approximation.Recent studies have shown promise in improving the prediction capability for incompressible separation flows by perturbing the Reynolds-stress anisotropy tensor.However,it remains uncertain whether this approach is effective for SWBLI flows,which involve compressibility and discontinuity.To address this issue,this study systematically quantifies the structural uncertainty of the anisotropy for oblique SWBLI flows.The eigenspace perturbation method is applied to perturb the anisotropy tensor predicted by the Menter Shear–Stress Transport(SST)model and reveal the impacts of anisotropy on the prediction of quantities of interest,such as separation and reattachment positions,wall static pressure,skin friction,and heat flux.The results demonstrate the potential and reveal the challenges of eigenspace perturbation in improving the SST model.Furthermore,a detailed analysis of turbulent characteristics is performed to identify the source of uncertainty.The findings indicate that eigenspace perturbation primarily affects turbulent shear stress,while the prediction error of the SST model is more related to turbulent kinetic energy.

含参麦、川芎嗪肺动脉灌注对犬体外循环血浆细胞因子的影响

【目的】研究含参麦、川芎嗪低温氧合血肺动脉灌注对犬体外循环血浆细胞因子的影响。【方法】18条杂种犬随机分为对照组、实验Ⅰ组、实验Ⅱ组,每组6条。三组犬均常规建立体外循环。实验Ⅰ组、Ⅱ组均于体外循环开始后行低温肺动脉灌注,实验Ⅱ组中灌注液为4∶1低温氧合血和乳酸钠林格液,并加入参麦注射液、盐酸川芎嗪。对照组不灌注,常规进行体外循环。根据血气分析计算呼吸指数(RI=AaDO2/PaO2)测定体外循环前(T1)、主动脉开放后5 min(T2)、体外循环结束时(T3)、体外循环结束后2 h(T4)各时点血浆中TNF-αI、L-6I、L-10含量。【结果】CPB开始后各时点实验Ⅱ组血浆TNF-α、IL-6均低于对照组(P<0.05)。T3、T4实验Ⅱ组TNF-α均显著低于其余两组(P<0.05)。T2、T3、T4时点实验Ⅱ组IL-6显著低于其他两组(P<0.05),三组犬血浆IL-10在CPB后逐渐增高,其中T2、T4时点实验Ⅱ组显著高于其他两组(P<0.05),CPB开始后对照组RI逐渐增高,实验Ⅱ组在CPB开始后各时点RI均低于其他两组(P<0.05,P<0.01)。【结论】含参麦、川芎嗪低温氧合血肺动脉灌注可降低促炎细胞因子的水平,提高抗炎细胞因子的水平而减轻体外循环相关全身炎症反应。

体外震波碎石治疗泌尿系结石400例

我院自1989年3月至1990年6月,应用德国西门子公司体外震波碎石机治疗泌尿系结石400例,取得满意效果,报道如下。

Extracorporeal shock wave lithotripsy for pancreatic and large common bile duct stones

Extraction of large pancreatic and common bile duct(CBD)calculi has always challenged the therapeutic endoscopist.Extracorporeal shockwave lithotripsy(ESWL)is an excellent tool for patients with large pancreatic and CBD calculi that are not amenable to routine endotherapy.Pancreatic calculi in the head and body are targeted by ESWL,with an aim to fragment them to<3 mm diameter so that they can be extracted by subsequent endoscopic retrograde cholangio-pancreatography(ERCP).In our experience,complete clearance of the pancreatic duct was achieved in 76% and partial clearance in 17%of 1006 patients.Short-term pain relief with reduction in the number of analgesics ingested was seen in 84%of these patients.For large CBD calculi,a nasobiliary tube is placed to help target the calculi,as well as bathe the calculi in salinea simple maneuver which helps to facilitate fragmenta-tion.The aim is to fragment calculi to<5 mm size and clear the same during ERCP.Complete clearance of the CBD was achieved in 84.4%of and partial clearance in 12.3%of 283 patients.More than 90%of the patients with pancreatic and biliary calculi needed three or fewer sessions of ESWL with 5000 shocks being de-livered at each session.The use of epidural anesthesia helped in reducing patient movement.This,together with the better focus achieved with newer third-gen-eration lithotripters,prevents collateral tissue damage and minimizes the complications.Complications in our experience with nearly 1300 patients were minimal,and no extension of hospital stay was required.Similar rates of clearance of pancreatic and biliary calculi with minimal adverse effects have been reported from the centers where ESWL is performed regularly.In view of its high efficiency,non-invasive nature and low complication rates,ESWL can be offered as the first-line therapy for selected patients with large pancreatic and CBD calculi.

Combination of low-energy shock-wave therapy and bone marrow mesenchymal stem cell transplantation to improve the erectile function of diabetic rats

Stem cell transplantation and low-energy shock-wave therapy （LESWT） have emerged as potential and effective treatment protocols for diabetic erectile dysfunction. During the tracking of transplanted stem cells in diabetic erectile dysfunction models, the number of visible stem cells was rather low and decreased quickly. LESWT could recruit endogenous stem cells to the cavernous body and improve the microenvironment in diabetic cavernous tissue. Thus, we deduced that LESWT might benefit transplanted stem cell survival and improve the effects of stem cell transplantation. In this research, 42 streptozotocin-induced diabetic rats were randomized into four groups： the diabetic group （n = 6）, the LESWT group （n = 6）, the bone marrow-derived mesenchymal stem cell （BMSC） transplantation group （n = 15）, and the combination of LESWT and BMSC transplantation group （n = 15）. One and three days after BMSC transplantation, three rats were randomly chosen to observe the survival numbers of BMSCs in the cavernous body. Four weeks after BMSC transplantation, the following parameters were assessed： the surviving number of transplanted BMSCs in the cavernous tissue, erectile function, real-time polymerase chain reaction, and penile immunohistochemical assessment. Our research found that LESWT favored the survival of transplanted BMSCs in the cavernous body, which might be related to increased stromal cell-derived factor-1 expression and the enhancement of angiogenesis in the diabetic cavernous tissue. The combination of LESWT and BMSC transplantation could improve the erectile function of diabetic erectile function rats more effectively than LESWT or BMSC transplantation performed alone.

Treatment of urinary lithiasis following kidney transplantation with extracorporeal shock-wave lithotripsy

Background The incidence of urinary lithiasis following kidney transplantation is very low, and decision-supporting data are not available. The aim of this study was to review the diagnosis and treatment of urinary lithiasis following kidney transplantation, which is of realistic significance to reduce urinary lithiasis following kidney transplantation, prolong the survival of renal allografts.Methods The incidence, diagnosis and treatment of urinary lithiasis in ten patients following kidney transplantation were analyzed retrospectively. Seven out of these patients had stones sized approximately 0.4-1.1 cm, and they were treated with low-voltage, low-frequency extracorporeal shock-wave lithotripsy （ESWL）. Two patients had stones sized ＜0.3 cm and they underwent cystoscopy and ureteroscopy. The ureteral catheter endoscopes were inserted in a retrograde manner to mobilize stones repeatedly. After elimination of obstruction, a ureteral double J stent was indwelt.One patient had a pelvic stone （1.2 cm）, which was removed surgically.Results The major clinical manifestations were hematuria, oliguria or anuria. Some patients were asymptomatic and they were diagnosed through laboratory tests and imaging examinations, e.g., ultrasonography. After elimination of obstruction, subjective symptoms disappeared in all patients, and the function of renal allografts recovered. A six-month follow-up indicated no remnant stones or lithiasis relapse.Conclusions The diagnosis and treatment of renal allograft lithiasis are challenging. After prompt and appropriate treatment, the prognosis was satisfactory, and permanent renal functional impairment did not occur in most patients.

Large-eddy simulation of shock-wave/turbulent boundary layer interaction with and without Spark Jet control

The efficiency and mechanism of an active control device ＂＇Spark Jet＂ and its application in shock-induced separation control are studied using large-eddy simulation in this paper. The base flow is the interaction of an oblique shock-wave generated by 8° wedge and a spatially-developing Ma = 2.3 turbulent boundary layer. The Reynolds number based on the incoming flow property and the boundary layer displacement thickness at the impinging point without shock-wave is 20000. The detailed numerical approaches were presented. The inflow turbulence was generated using the digital filter method to avoid artificial temporal or streamwise periodicity. The , merical results including velocity profile, Reynolds stress profile, skin friction, and wall pressure were sys- tematically validated against the available wind tunnel particle image velocimetry （PIV） measure- ments of the same flow condition. Further study on the control of flow separation due to the strong shock-viscous interaction using an active control actuator ＂＇Spark Jet＇＂ was conducted. The single-pulsed characteristic of the device was obtained and compared with the experiment. Both instantaneous and time-averaged flow fields have shown that the jet flow issuing from the actuator cavity enhances the flow mixing inside the boundary layer, making the boundary layer more resis- tant to flow separation. Skin friction coefficient distribution shows that the separation bubble length is reduced by about 35% with control exerted.

A study on turbulence transportation and modification of Spalart–Allmaras model for shock-wave/turbulent boundary layer interaction flow

It is of great significance to improve the accuracy of turbulence models in shock-wave/ boundary layer interaction flow. The relationship between the pressure gradient, as well as the shear layer, and the development of turbulent kinetic energy in impinging shock-wave/turbulent bound- ary layer interaction flow at Mach 2.25 is analyzed based on the data of direct numerical simulation （DNS）. It is found that the turbulent kinetic energy is amplified by strong shear in the separation zone and the adverse pressure gradient near the separation point. The pressure gradient was non-dimensionalised with local density, velocity, and viscosity. Spalart Allmaras （S A） model is modified by introducing the non-dimensional pressure gradient into the production term of the eddy viscosity transportation equation. Simulation results show that the production and dissipation of eddy viscosity are strongly enhanced by the modification of S-A model. Compared with DNS and experimental data, the wall pressure and the wall skin friction coefficient as well as the velocity profile of the modified S-A model are obviously improved. Thus it can be concluded that the mod- ification of S-A model with the pressure gradient can improve the predictive accuracy for simulat- ing the shock-wave/turbulent boundary laver interaction.

Simulation of flow-field interior dust removal system at a transit point and the overall technology of dust removal

In order to make a reasonable dry-type dust removal plan of the coal transit spot in a coal washery,it is essential to install the dust removal fan and guide chute.By means of the numerical simulation,the pollution mechanism at a transit point and the flow-field interior dust removal system had been analyzed.The result shows that the dust pollution at transit spot is mainly cased by the joint effort of induced airflow and shock-wave.With the appropriate dust removal fan and the guide chute,will effectively eliminate the positive pressure by gave rise to by the impact of falling coal,also avoid the secondary pollution.

Design and Parameter Analysis for Explosive-Driven Demagnetization Pulsed Power Source

We design a pulsed power source based on the technique for explosive-driven demagnetization. The physical process and geometry structure of this power source are described in detail and several formulae are deduced to predict some important properties of the power source. With a φ 40 mm × 20 mm× 10 mm cylindrical magnet, the maximum output voltage and current reaches 125.5 V and 862.9A, respectively. The rise time of the front edge of the output voltage is about 264ns. On the 0.05 Ω simulative load, the net power is 37kW.

Third-order modified coeffcient scheme based on essentially non-oscillatory scheme

A third-order numerical scheme is presented to give approximate solutions to multi-dimensional hyperbolic conservation laws only using modified coefficients of an essentially non-oscillatory （MCENO） scheme without increasing the base points during construction of the scheme. The construction process shows that the modified coefficient approach preserves favourable properties inherent in the original essentially nonoscillatory （ENO） scheme for its essential non-oscillation, total variation bounded （TVB）, etc. The new scheme improves accuracy by one order compared to the original one. The proposed MCENO scheme is applied to simulate two-dimensional Rayleigh-Taylor （RT） instability with densities 1：3 and 1：100, and solve the Lax shock-wave tube numerically. The ratio of CPU time used to implement MCENO, the .third-order ENO and fifth-order weighed ENO （WENO） schemes is 0.62：1：2.19. This indicates that MCENO improves accuracy in smooth regions and has higher accuracy and better efficiency compared to the original ENO scheme.

Investigation of Shock Waves in Non-Ideal Gas under the Action of Magnetic Field

In present paper, certain aspect of shock wave in non-ideal gas, when magnetic field is orthogonal to the trajectories of the gas particles and electrical conductivity is taken to be infinite, is investigated. Considering one-dimensional unsteady non-planer motion, basic equations, its general solution and formation of shock-wave, conservation laws and jumps conditions, variation of area of non-uniform cross section and analytical solution of strong non planer shock is obtained.

THE FIRST CHOICE OF TREATMENT FOR URINARY INFECTED RENAL STONES

Objective To investigate the appropriate treatment of infectious renal stones. Methods Between April 1999 and June 2006, 60 patients presented to our department with infectious renal stones. Twenty-nine patients were treated by extracorporeal shock-wave lithortripsy(ESWL) only, 31 patients were given a combination therapy. Thirty-four males and 26 females were evaluated by routine urine tests including urine culture and sensitivity before ESWL treatments. The total number of shock waves varied from 1 600 to 2 800 and the energy levels ranged from 1 to 6 unit. Results The fragmentation after ESWL was 61.6%; 18.3% after 2 ESWL sessions, 8.3% after 3 ESWL sessions, 5.0% after 4 ESWL sessions, 3.3% after 7 ESWL sessions and 1.66% after 9 ESWL sessions. Only one (1.66%) patient failed and changed to open surgery. Conclusion ESWL is an effective and reliable treatment for patients with infectious renal stones. However, better effects and shorter treatment time is obtained by the combination therapy of ESWL with other therapy options.

TREATMENT OF CYSTINE CALCULUS WITH EXTRACOR-POREAL SHOCK WAVE LITHOTRIPSY

Objective To evaluate the effectiveness of ESWL for treating patients with cystine calculus. Methods Of 31 patients, 20 were subjected to ESWL only, 6 were subjected to combination therapy of PCNL and ESWL, 2 Pneumatic Lithotriptor-ESWL, 3 Laser lithotripsy-ESWL. Results For 14 renal stones, the fragmentation after ESWL manotherapy was 85. 7% and 14.3% after twice ESWL sessions. For 17 ureter calculus, the fragmentation after ESWL manotherapy was 82.3% and 11.7% after twice ESWL sessions. One patient （ 5.8% ） failed and changed to open surgery. Conclusion ESWL is an effective and reliable method for treating patients with cystine calculus, however, better effects and shorter treatment time could be obtained by the combination of ESWL with other therapy options.

Level Set interface treatment and its application in Euler method

Level Set interface treatment method is introduced into Euler method,which is employed for interface treatment method for multi-materials. Combined with the ghost fluid method,the moving interface is tracked. Fifth-order WENO spatial discretization and third-order TVD Runge-Kutta time discretization methods are used. Shock-wave action on bubble,implosion and velocity field Shock effect bubbles; implosion and velocity field are simulated by means of LS-MMIC3D programmed by C++. Nu-merical results show that the Level Set interface treatment method is effective and feasible for multi-material interface treatment in comparison with the WENO method.

Reconstruction of skin friction topology in complex separated flows

This paper describes a theoretical method for reconstruction of the skin friction topology in complex separated flows,which is developed based on the exact relation between skin friction and surface pressure through the boundary enstrophy flux(BEF).The key of this method is that a skin friction field is reconstructed from a surface pressure field as an inverse problem by applying a variational method.For applications,the approximate method is proposed,where the composite surface pressure field is given by a linear superposition of the base-flow surface pressure field and the surface pressure variation field and the base-flow BEF field is used as the first-order approximation.This approximate method is constructive in a mathematical sense since a complex skin friction field in separated flows can be reconstructed from some elemental skin friction structures(skin friction source/sink,vortex and their combinations)by a linear superposition of some simple surface pressure structures.The distinct topological features,such as critical points,separation lines and attachment lines,naturally occur as a result of such reconstruction.As examples,some elemental skin friction structures in separated flows are reconstructed in simulations,and the skin friction fields in shock-wave/boundary-layer interactions(SWBLIs)are reconstructed from pressure sensitive paint(PSP)images obtained in wind tunnel experiments.