Pressure Test System Research Articles

The Application of stressTesting in Bank Risk Management

In recent years, along with bank management become more and more attention to risk management, bank managers by adopt the method of stress tests for Banks manage risk factors in the process of operation, when the bank there was a risk management system, pressure test system will be automatically, which can identify the risk factors at the same time to remind the bank management. This paper mainly through the risk management system in the stress test technology analysis, mainly from the bank stress test to the bank risk management application, the feasibility and necessity of the existence of stress test and the advantages of stress test analysis.

A 4-Channel High-Precision Real-Time Pressure Test System for Irregularly Variable High Temperature Environments

In this study, a 4-channel high-precision pressure test system was designed. It implements high-precision measurement of pressure parameters at multiple test points in situ and synchronously in irregularly variable high-temperature environments. The test system consists of a pressure–temperature double-parameter composite sensor along with signal acquisition, temperature compensation algorithm processing, and real-time online display modules. The temperature-sensitive chip of the sensor was integrated on the surface of the differential pressure-sensitive chip for in-situ temperature compensation. The collected pressure-temperature parameters were calculated and displayed using the temperature compensation algorithm processing and real-time online display modules. Finally, a high-precision pressure test was conducted. The proposed test system realizes the pressure test in high-temperature environments with irregular variations in the range of 24–400 °C, with a test error of less than 0.95% and a sensitivity of 6.378 mV/kPa. The study results can be used for real-time monitoring of high-precision pressure of key components operating in irregularly variable high-temperature environments, which provides a significant guarantee for the normal operation of equipment.

Shock characteristics evolution of detonation waves forward impacting on the solid wall

The forward reflection of detonation waves on the solid wall will lead to a high pressure rise. The research systematically introduced the theoretical, numerical, and experimental exploration on the shock propagation characteristics of detonation waves forward impacting on a solid wall in the present work. The one-dimensional shock theory was carried out to solve the pressure rise ratio in this process. The exact solution and its variation law of a positive increase with filling pressure were expressed. One-dimensional simulations based on the space-time conservation element and solution element method were utilized to reveal the pressure decrease and velocity increase laws for the reflected shock wave. The blockage, oscillation, and attenuation phenomena of detonation waves and reflected shock waves under the effect of the tube–wall reflection were demonstrated in two-dimensional works. Experimental results from the detonation tube pressure test system showed a larger amplitude and duration of the reflected shock wave than the detonation wave. Pressure evolution and the formation of pressure plateaus were consistent with the simulation results. In addition, the time required for the pressure plateaus to decay to 0.5 times the Chapman-Jouget (C–J) detonation pressure is relatively constant under different filling conditions.

Constitutive Model of N15 Propellant considering the Confining Pressure Effect

To describe the effect of confining pressure on the mechanical responses of N15 propellant, a constitutive model considering the confining pressure effect was first established for N15 propellant based on the elastic-viscoelastic correspondence principle. Then, the mechanical properties of N15 solid propellant under different confining pressures were obtained using confining pressure test system, and the obtained results indicate that the initial modulus of propellant did not change with confining pressure, but the maximum tensile strength, rupture strength, the maximum elongation, and elongation at break increased with increasing confining pressure. In conjunction with propellants’ mesoscopic structure and cross-section analysis, the mechanical mechanism of confining pressure effect on propellant was initially disclosed. Due to confining pressure, the particle dewetting inside the propellant was reduced, the hole propagation was delayed, and crack extension inhibited germination, proving that confining pressure has a strengthening impact on the propellant. Finally, assuming that the model parameters were dependent on pressure, the model parameters acquisition and validation were conducted. The results demonstrated that constitutive model can describe confining pressure influence on the mechanical properties of N15 propellant accurately.

Study on the relationship between the toe-out gait and foot hallux valgus in the elderly Chinese

The study selects 50 senior people at the age of more than 60 and 30 young people at the age of 18-26 as test group and control group respectively, including people with mild foot disease, such as flat feet, pes cavus and hallux valgus. Questionnaire survey of effective data volume and observation are used to understand common problems of the foot in the elderly, collect shape photos of the foot in senior people, and subjectively analyze their foot shape and gait characteristics. Footscan plate plantar pressure test system and Kistler 3D force platform are used to objectively analyze plantar pressure distribution and gait characteristics of subjects. According to study results: Toe-out gait causes the plantar pressure to move to the forefoot, therefore, the forefoot is the part with the highest risk of injury of foot in toe-out gait, especially the first toe, causing hallux valgus and various foot problems. The toe-out gait causes increase of gait cycle, slow walking speed, poor buffer effect, and may bring pain in feet and lower extremities, thus affecting the dynamic characteristics of the entire lower limb.

Electroacupuncture Pretreatment at Neiguan (PC6) attenuates autophagy in rats with myocardial ischemia reperfusion through the phosphatidylinositol 3-kinase-Akt-mammalian target of rapamycin pathway.

To investigate the protective efficacy of electroacupuncture (EA) pretreatment at Neiguan (PC6) on myocardial ischemia-reperfusion (I/R) in rats. Fifty rats were randomly divided into five groups (n = 10): sham operation group, model group (underwent in vivo myocardial I/R), EA pretreatment group [EA at Neiguan (PC 6) 1 week before I/R], wortmannin group (1 week before I/R, the PI3K inhibitor, wortmannin, was injected), EA pretreatment + wortmannin group (both pretreatments were performed simultaneously). After establishing the I/R model, 2,3,5-triphenyltetrazolium chloride (TTC) staining was used to analyze the weight and area of the myocardial infarction tissue. The biosignal and pressure test system was used to determine the left ventricular systolic mean pressure (LVSP), left ventricular end-diastolic pressure (LVEDP), fractional shortening (FS), and ejection fraction (EF). Ultraviolet spectrophotometry was used to determine the expression of creatine kinase (CK)-MB, inducible nitric oxide synthase (iNOS), and total antioxidant capacity (T-AOC) in the serum. The expression of autophagy-related protein 13 (ATG13), mammalian target of rapamycin (mTOR), and phosphatidylinositol 3-kinase (PI3K) in cardiac muscle cells was determined by immunofluorescence. Hematoxylin and eosin staining was used to observe autophagy-related pathological changes in rat cardiomyocytes, and ultrastructural changes of cardiomyocytes were examined by transmission electron microscopy. In this study, the infarction size and tissue weight of the EA pretreatment group were decreased compared with the model group (P < 0.0001). Furthermore, compared with the model group, the LVEDP values of the EA pretreatment group were significantly reduced (P = 0.0091), and the LVSP, FS, and EF values were slightly increased (P = 0.0007, 0.0020, 0.0031). EA pretreatment also significantly decreased the expression of CK-MB and iNOS, while it increased the expression of T-AOC in the serum of rats with I/R injury (P < 0.0001). Furthermore, EA pretreatment slightly widened the myocardial fiber space, reduced necrosis and myocardial cell swelling and maintained the nucleus and mitochondria structure intact. EA pretreatment promoted autophagy flux and alleviated myocardial I/R injury through the PI3K-Akt-mTOR pathway.

Effects of fatigue on biomechanics of forehand smash in badminton

Sports fatigue will cause deformation of actions. In this study, badminton was analyzed, and the influence which was brought by fatigue was studied from the perspective of biomechanics. The forehand smash of professional badminton athletes under normal and fatigue states was tested. The biomechanical indexes of athletes were obtained by infrared remote shooting test system and plantar pressure test system for comparison. The results showed that the forehand smash effect of athletes was significantly worse under fatigue state, the maximum gravity center height decreased to 1.22 ± 0.14 m, and the maximum gravity center speed decreased to 2.33 ± 0.12 m/s, which showed significant decreases compared to the normal state (P&lt; 0.05). Moreover the maximum velocity of the right upper arm, right forearm, elbow joint, wrist joint and knee joint decreased significantly (P&lt; 0.5), the maximum angle of the right hip joint, knee joint and left ankle joint also decreased significantly. The pressure of the inner side of the forefoot and the pressure in the middle of the forefoot increased (P&lt; 0.05). The biomechanical analysis of forehand smash under fatigue condition reveals the relationship between fatigue and movement, which provides some scientific bases for the reasonable control of sports load.

Development of High Pressure and Constant Low Flow Test System for Hydraulic Support Safety Valve

The existing test equipment for safety valve with low-flow start and overflow closure characteristics of hydraulic support cannot provide the test conditions stipulated in relevant standards, which affects the accuracy of test results. Aiming at the shortage of the existing test equipment, a test system of high pressure and low flow rate of safety valve with hydraulic support is designed, and a technical solution of using straight line driver to push the plunger cylinder to realize high pressure and low flow rate of liquid supply is put forward. The simulation software AMESim was used to construct the virtual prototype of the test system, and the simulation analysis was carried out to determine the main parameters and the influencing rules of the rigidity of the liquid supply velocity. Based on the simulation study, prototype trial production, flow calibration and field experiment were completed. The experimental results showed that the instantaneous output flow fluctuation of the test system was within the range of ±10% of the rated value of 40ml/min, and the output flow fluctuation range was reduced by 25% compared with the existing way.

Design of Electronic Blood Pressure Testing System

With the continuous development of electronic technology, the previous traditional methods of blood pressure testing are far from meeting people’s requirements. Fortunately, the advent of electronic blood pressure meters has shown great convenience and potential. Against the backdrop, a new electric blood pressure testing system based on a CC3200 LaunchPad is proposed in this paper, which uses a pressure sensor to collect the information of static pressure and fluctuation of blood pressure, and then transmits the processed data to the software in PC. The software in PC analyzes the data by oscillometric method and Gaussian fitting method, and then the static pressure, systolic pressure and diastolic pressure are calculated and displayed. Test results show that the blood pressure testing efficiency is greatly improved by this system with its high accuracy and reliability, which can meet the requirement of the AAMI (Association for the Advancement of Medical Instrumentation) standard.

Effect of metal powders on explosion of fuel-air explosives with delayed secondary igniters

In order to improve the energy level of fuel air explosive(FAE) with delayed secondary igniters, high energetic metal powders were added to liquid fuels mainly composed of ether and isopropyl nitrate. Metal powders’ explosive properties and reaction mechanisms in FAE were studied by high-speed video, pressure test system, and infrared thermal imager. The results show that compared with pure liquid fuels, the shock wave overpressure, maximum surface fireball temperature and high temperature duration of the mixture were significantly increased after adding high energetic metal powder. The overpressure values of the liquid-solid mixture at all measuring points were higher than that of the pure liquid fuels. And the maximum temperature of the fireball was up to 1700 °C, which was higher than that of the pure liquid fuels. After replacing 30% of aluminum powder with boron or magnesium hydride, the shock wave pressure of the mixture was further increased. The high heat of combustion of boron and the hydrogen released by magnesium hydride could effectively increase the blast effect of the mixture. The improvement of the explosion performance of boron was better than magnesium hydride. It shows that adding high energetic metal powder to liquid fuels can effectively improve the explosion performance of FAE.

Analysis of pressure distribution during movement for the top part of female socks

Female sports socks were studied to achieve the correlation between the ankle surface curvature and pressure distribution of the top part of socks. The transverse tension performance of the socks’ top part was obtained using an Instron universal strength tester, and the leg size was measured with a [TC]2 contactless 3D body scanner. The pressure was monitored by a Pliance-X-32 pressure test system. Gray correlation, variance, and regression analysis were applied to study the correlation between movement velocity, fabric performance, leg circumference, and ankle pressure distribution. The dynamic pressure prediction models of multiple regression and back propagation (BP) neural network on the top part of socks were also established. The results show that the transverse tension performance and sock density have a significant effect on the ankle static pressure. Movement velocity, sock density, and leg circumference are positively correlated with dynamic pressure, while the elastic recovery rate of the fabric is negatively correlated with the pressure. Both of the multiple regression and BP neural network models can predict the dynamic pressure, and the BP neural network model is better than multiple regression at prediction error, which was kept to less than 0.5%. Therefore, the BP neural network model can be effectively used in female ribbed sock top design.

Experimental research on damage characteristics of CFRP/aluminum foam sandwich structure subjected to high velocity impact

In view of the wide demands of sandwich structure with porous material as core layer in many important fields such as protection engineering, aerospace, automobile manufacturing and ship, etc. In order to reveal the energy absorption and damage characteristics of high velocity impact aluminum foam core and CFRP/aluminum foam core structure, the quasi-static loading system, one-stage light gas gun loading system, the impact pressure testing system and the high-speed camera acquisition system were used to perform the quasi-static compression experiments of aluminum foam and the projectiles with different materials impacting on the aluminum foam core and CFRP/aluminum foam sandwich structure at the speeds of 100–300 m/s. The influences of impact velocity and projectile’ density on the damage characteristics of CFRP/aluminum foam sandwich structure and the attenuation effect of shock wave in sandwich structure have been studied. The experimental results showed that the curve of stress and strain has three typical zones similar to porous materials: elastic zone, yield platform zone and compaction zone under quasi-static compression loading. Due to its brittle and low tensile strength of aluminum foam material, the single aluminum foam plate has poor ballistic performance under the high-speed impact of projectiles with different materials. Therefore, closed cell aluminum foam needs to be combined with high strength panels to form sandwich structure to improve its ballistic performance.

Optimum Design of Structural Parameters for Thin-walled Metal Container

In order to further increase the volume, reduce the weight and manufacturing cost, the key structural parameters of thin-walled metal packing container are optimized. The instability conditions under circumferential external pressure and axial load are analyzed, a mathematical model with the constraint of critical instability strength, the maximum volume and minimum mass as the objective is constructed. Multi-objective optimization method with nonlinear constraints is used to solve the key structural parameters, such as wall thickness, diameter and height, and the optimization result is calculated by fgoalattain() function in the Matlab optimization toolbox. The instability pressure test system is constructed, the instability pressure of the optimized thin-wall metal packing container is tested. The results show that the unstable pressure is higher than 120kPa, which are better than the design index.

Theoretical Calculation and Experimental Analysis on Initial Shock Pressure of Borehole Wall under Axial Decoupled Charge

This paper attempts to calculate the exact initial shock pressure of borehole wall induced by the blasting with axially decoupled charge. For this purpose, Starfield superposition was introduced considering the attenuation and superposition of blasting pressure, and the theoretical solution of initial borehole wall pressure was obtained for the upper and middle air‐decked charging structures. Then, the explosive pressure field around the borehole was measured by cement mortar models and a dynamic pressure test system, and the pressures at multiple measuring points were simulated with numerical models established by ANSYS/LS‐DYNA. The results show that the deviations between simulated and theoretical pressures are smaller than 10%, indicating the reliability of the theoretical formula derived by Starfield superposition. For the upper air‐decked charging structure, the initial shock pressure of the charging section followed a convex distribution, with the peak value near the charge centre. With the increase in the distance from the charging section, the borehole wall shock pressure in the air gap underwent a sharp decline initially before reaching a relatively constant level. The minimum pressure was observed at the hole collar. For the middle air‐decked charging structure, the pressures at both ends of the charging section obeyed a convex distribution, with the peak value near the charge centre. Finally, the author optimized air‐decked charging structure of periphery boreholes within Grade III surrounding rocks of Banjie tunnel, China, and proved the enhancement effect of the theoretical findings on smooth blasting. The research findings provide valuable references to the theoretical and experimental calculation of air column length and other key parameters of air‐deck blasting and shed new light on the charging structure determination of smooth blasting and blasting vibration control for the excavation of large‐section, deep mining roadways.

Performance analysis for difficult airway equipment: Standardising for success

Equipment design and selection can contribute to the success or failure of difficult airway management. However, evaluative systems for providing the relative performance data for bougie introducers to help inform these choices do not exist outside of bespoke studies. This paper discusses the design development of an innovative tip pressure and shape retention testing system. Working with a design activity model, a set of stringent criteria to inform the manufacture of the testing systems were produced. Once implemented, this testing method can inform future equipment selection to improve procedure success rates and thereby reduce patient complications.

Thermal and Pressure-Assisted Thermal Destruction Kinetics for Spores of Type A Clostridium botulinum and Clostridium sporogenes PA3679

The purpose of this study was to determine the inactivation kinetics of the spores of the most resistant proteolytic Clostridium botulinum strains (Giorgio-A and 69-A, as determined from an earlier screening study) and of Clostridium sporogenes PA3679 and to compare the thermal and pressure-assisted thermal resistance of these spores. Spores of these strains were prepared using a biphasic medium method. C. sporogenes PA3679 spores were heat treated before spore preparation. Using laboratory-scale and pilot-scale pressure test systems, spores of Giorgio-A, 69-A, and PA3679 suspended in ACES [N-(2-acetamido)-2-aminoethanesulfonic acid] buffer (pH 7.0) were exposed to various combinations of temperature (93 to 121°C) and pressure (0.1 to 750 MPa) to determine their resistance. More than a 5-log reduction occurred after 3 min at 113°C for spores of Giorgio-A and 69-A and after 5 min at 117°C for spores of PA3679. A combination of high temperatures (93 to 121°C) and pressures yielded greater log reductions of spores of Giorgio-A, 69-A, and PA3679 compared with reduction obtained with high temperatures alone. No survivors from initial levels (>5.0 log CFU) of Giorgio-A and 69-A were detected when processed at a combination of high temperature (117 and 121°C) and high pressure (600 and 750 MPa) for <1 min in a pilot-scale pressure test system. Increasing pressure from 600 to 750 MPa at 117°C decreased the time from 2.7 to 1 min for a >4.5-log reduction of PA3679 spores. Thermal D-values of Giorgio-A, 69-A, and PA3679 spores decreased (i.e., 29.1 to 0.33 min for Giorgio-A, 40.5 to 0.27 min for 69-A, and 335.2 to 2.16 min for PA3679) as the temperature increased from 97 to 117°C. Pressure-assisted thermal D-values of Giorgio-A, 69-A, and PA3679 also decreased as temperature increased from 97 to 121°C at both pressures (600 and 750 MPa) (i.e., 17.19 to 0.15 min for Giorgio-A, 9.58 to 0.15 min for 69-A, and 12.93 to 0.33 min for PA3679 at 600 MPa). At higher temperatures (117 or 121°C), increasing pressure from 600 to 750 MPa had an effect on pressure-assisted thermal D-values of PA3679 (i.e., at 117°C, pressure-assisted thermal D-value decreased from 0.55 to 0.28 min as pressure increased from 600 to 750 MPa), but pressure had no effect on pressure-assisted thermal D-values of Giorgio-A and 69-A. When compared with Giorgio-A and 69-A, PA3679 had higher thermal and pressure-assisted thermal D-values. C. sporogenes PA3679 spores were generally more resistant to combinations of high pressure and high temperature than were the spores of the C. botulinum strains tested in this study.

The Influence of Sintering Temperature on Properties of Silicon Carbide Porous Ceramic Filter Membrane

The average particle size of SiC used as raw materials is 60 μm, the filter membrane in a mass ratio of each component are: SiC : binder: sodium carboxymethyl cellulose (CMC): deionized water =9:1:1:20. Method of producing membrane by means of spin coating, the sintering temperature was set in different ranges. The Archimedes drainage method was used to measure its porosity, and the filter pressure of membrane was charactered by the filter pressure testing system, SEM was performed to characterize its surface morphology and microstructure. The results show that: when the temperature rises from 1225 °C to 1325 °C, the filter pressure of SiC porous ceramic filter membrane decrease firstly and then increase; the atlas trend of the porosity is roughly opposite with the filter pressure, the maximum of the porosity value is about 42% when the temperature reaches 1300°C, at this temperature, the filter pressure reaches a minimum value and the surface of the filtration membrane is the most flat. When the temperature reaches 1350 °C, the surface of the film started showing a plaque.

Preparation and Properties of Silicon Carbide Porous Ceramic Filter Membrane

Spin coating method was adopted for preparation of two types of SiC filter membrane with different particles size. Sintering temperature was set at 1300°C. SEM was performed in order to characterize its micro-structure. For measuring the porosity of the membrane, we used Archimedes drainage method. The filter pressure testing system was used to character the membrane filter pressure drop. The experiment results indicated that, when the filter membrane was composed of average diameters 45μm and 23μm SiC particles, with their thickness reached about 300μm and 150μm respectively and the amount of ceramic binder was 10%, the porosity of the membrane achieved 43%, the surface of filtration membrane structure was uniform, and its filter pressure was smaller. On the premise of satisfying specific filtering accuracy and efficiency, larger size of silicon carbide particle could offer better performance of the membrane.

Load rate of facet joints at the adjacent segment increased after fusion.

Background:The cause of the adjacent segment degeneration (ASD) after fusion remains unknown. It is reported that adjacent facet joint stresses increase after anterior cervical discectomy and fusion. This increase of stress rate may lead to tissue injury. Thus far, the load rate of the adjacent segment facet joint after fusion remains unclear.Methods:Six C2–C7 cadaveric spine specimens were loaded under four motion modes: Flexion, extension, rotation, and lateral bending, with a pure moment using a 6° robot arm combined with an optical motion analysis system. The Tecscan pressure test system was used for testing facet joint pressure.Results:The contact mode of the facet joints and distributions of the force center during different motions were recorded. The adjacent segment facet joint forces increased faster after fusion, compared with intact conditions. While the magnitude of pressures increased, there was no difference in distribution modes before and after fusion. No pressures were detected during flexion. The average growth velocity during extension was the fastest and was significantly faster than lateral bending.Conclusions:One of the reasons for cartilage injury was the increasing stress rate of loading. This implies that ASD after fusion may be related to habitual movement before and after fusion. More and faster extension is disadvantageous for the facet joints and should be reduced as much as possible.

Film cooling effects on the tip flow characteristics of a gas turbine blade

An experimental investigation of the tip flow characteristics between a gas turbine blade tip and the shroud was conducted by a pressure-test system and a particle image velocimetry (PIV) system. A three-times scaled profile of the GE-E3 blade with five film cooling holes was used as specimen. The effects on flow characteristics by the rim width and the groove depth of the squealer tip were revealed. The rim widths were (a) 0.9%, (b) 2.1%, and (c) 3.0% of the axial chord, and the groove depths were (a) 2.8%, (b) 4.8%, and (c) 10% of the blade span. Several pressure taps on the top plate above the blades were connected to pressure gauges. By a CCD camera the PIV system recorded the velocity field around the leading edge zone including the five cooling holes. The flow distributions both in the tip clearance and in the passage were revealed, and the influence of the inlet velocity was determined. In this work, the tip flow characteristics with and without film cooling were investigated. The effects of different global blowing ratios of M=0.5, 1.0, 1.3 and 2.5 were established. It was found that decreasing the rim width resulted in a lower mass flow rate of the leakage flow, and the pressure distributions from the leading edge to the trailing edge showed a linearly increasing trend. It was also found that if the inlet velocity was less than 1.5m/s, the flow field in the passage far away from the suction side appeared as a stagnation zone.