Elimination of Fuel Pressure Fluctuation and Multi-injection Fuel Mass Deviation of High Pressure Common-rail Fuel Injection System

The influence of fuel pressure fluctuation on multi-injection fuel mass deviation has been studied a lot,but the fuel pressure fluctuation at injector inlet is still not eliminated efficiently.In this paper,a new type of hydraulic filter consisting of a damping hole and a chamber is developed for elimination of fuel pressure fluctuation and multi-injection fuel mass deviation.Linear model of the improved high pressure common-rail system（HPCRS）including injector,the pipe connecting common-rail with injector and the hydraulic filter is built.Fuel pressure fluctuation at injector inlet,on which frequency domain analysis is conducted through fast Fourier transformation,is acquired at different target pressure and different damping hole diameter experimentally.The linear model is validated and can predict the natural frequencies of the system.Influence of damping hole diameter on fuel pressure fluctuation is analyzed qualitatively based on the linear model,and it can be inferred that an optimal diameter of the damping hole for elimination of fuel pressure fluctuation exists.Fuel pressure fluctuation and fuel mass deviation under different damping hole diameters are measured experimentally,and it is testified that the amplitude of both fuel pressure fluctuation and fuel mass deviation decreases first and then increases with the increasing of damping hole diameter.The amplitude of main injection fuel mass deviation can be reduced by 73%at most under pilot-main injection mode,and the amplitude of post injection fuel mass deviation can be reduced by 92%at most under main-post injection mode.Fuel mass of a single injection increases with the increasing of the damping hole diameter.The hydraulic filter proposed by this research can be potentially used to eliminate fuel pressure fluctuation at injector inlet and improve the stability of HPCRS fuel injection.

ESTIMATE OF BURSTING PRESSURE OF MILD STEEL PRESSURE VESSEL AND PRESENTATION OF BURSTING FORMULA

In order to get more precise bursting pressure formula of mild steel, hundreds of bursting experiments of mild steel pressure vessels such as Q235（Gr.D） and 20R（1020） are done. Based on statistical data of bursting pressure and modification of Faupel formula, a more precise modified formula is given out according to the experimental data. It is proved to be more accurate after examining other bursting pressure value presented in many references. This bursting formula is very accurate in these experiments using pressure vessels with different diameter and shell thickness. Obviously, this modified bursting formula can be used in mild steel pressure vessels with different diameter and thickness of shell.

PRESSURE COMPENSATION METHOD OF UNDERWATER HYDRAULIC SYSTEM WITH HYDRAULIC POWER UNIT BEING UNDER ATMOSPHERIC CIRCUMSTANCE AND PRESSURE COMPENSATED VALVE

Based on the analysis of the-state-of-the-art of pressure compensation of underwater hydraulic systems （UHSs）, a new method of pressure compensation of UHSs, whose hydraulic power unit is in the atmospheric circumstance, is proposed. And a pilot-operated relief valve with pressure compensation is realized. The pressure compensation precision is guaranteed by direct detection. Its dynamic performance and stability are improved by a dynamic feedback. Theoretical study, simulation and experiment show that the pilot-operated relief valve with pressure compensation has a fine property of tracking underwater ambient pressure and meet the requirement of underwater ambient pressure compensation.

A NEW MODEL FOR CALCULATING PROPAGATION PRESSURE AND INITIATION PRESSURE OF PIPELINES WITH A LOCAL DENT

An analytical model of a ring with six yield hinges and two deformable arc segments is presented for. the prediction of the buckle propagation pressure and initiation pressure in offshore pipelines. The configuration of a fully collapsed ring is considered as a real dumbbell shape with a line touch between two 'bells', instead of the dumbbell shape with a point touch of two diametrically opposite points. Calculations are performed assuming that the dominant effect on the plastic energy dissipation has the circumferential bending mode. For the linear strain-hardening materials it is found that theoretical predictions based on the above model for both propagation pressure and initiation nressure are in good agreement with experimental results of Kyriakides et al.

Practical application of pressure regulating technology for fire district in Meiyukou Coal Mine

Based on the simulated laboratory experiment of pressure balance for fire ex- tinguishing,the pressure regulating technology was summarized for the fire district in Meiyukou Coal Mine.The technology includes three measures for air pressure regulation, namely applying the pressure regulating chamber to balance the air pressure of fire district, increasing the air pressure of the working face,and filling the ground surface fractures.A good effect was obtained to prevent and extinguish the fire.When the measures fail to in- crease the pressure of working face or to regulate that of air chamber,the measure to fill the ground surface fractures will play an important role.

A modified relation between the intraocular and intracranial pressures

A modified relation between the intraocular and intracranial pressures is presented by employing the least square method to fit the existing experiments. Relative analysis here indicates that this modified relation not only is better than the previous relation by comparing with the existing experimental data but also overcomes the induced singularity in applying the existing mechanical models to compute the mechanical properties of the lamina cribrosa. The present study will be a beneficial help to understanding the relationship between the intraocular and intracranial pressures and even glaucomatous developing.

Influence of Polar Pressure Transmission Medium on the Pressure Coefficient of Excitonic Interband Transitions in Monolayer WSe_2

The influence of the pressure transmission medium（PTM）on the excitonic interband transitions in monolayer tungsten diselenide（WSe2）is investigated using photoluminescence（PL）spectra under hydrostatic pressure up to 5GPa.Three kinds of PTMs,condensed argon（Ar）,1：1 n-pentane and isopentane mixture（PM）,and4：1 methanol and ethanol mixture（MEM,a PTM with polarity）,are used.It is found that when either Ar or PM is used as the PTM,the PL peak of exciton related to the direct K-K interband transition shows a pressure-induced blue-shift at a rate of 32±4 or 32±1 meV/GPa,while it turns to be 50±9meV/GPa when MEM is used as the PTM.The indirect A-K interband transition presents almost no shift with increasing pressure up to approximatel.y 5 GPa when Ar and PM are used as the PTM,while it shows a red-shift at the rate of-17±7meV/GPa by using MEM as the PTM.These results reveal that the optical interband transitions of monolayer WSe2 are very sensitive to the polarity of the PTM.The anomalous pressure coefficient obtained using the polar PTM of MEM is ascribed to the existence of hydrogen-like bonds between hydroxyl in MEM and Se atoms under hydrostatic pressure.

Inhomogeneous Dielectric Target Properties for Increased Non-thermal Pressure in Laser Boron Fusion by CPA-Pulses

Based on the documentation of the invited paper and the subsequent discussion at a virtual conference,discoveries are indicated,which are summarized in the following paper for further evaluation on the topic of non-thermal forces using terms of extremely powerful components of Maxwell’s stress tensor at the interaction of CPA(chirped pulse amplification)laser pulses in the fusion plasmas of hydrogen with the isotope 11 of boron.This is caused by a recoil mechanism given by the Fresnel formulas of the suppression of the reflectivity of inhomogeneous plasma given by optical constants of the plasma properties.

Serpentine Inlet Performance Enhancement Using Vortex Generator Based Flow Control

In order to provide the line-of-sight blockage of the engine face for an advanced Uninhabited Combat Air Vehicle（UCAV）, a highly curved serpentine inlet is proposed and experimentally studied. Based on the static pressure distribution measurement along the wall, the flow separation is found at the top wall of the second S duct for the baseline inlet design, which yields a high flow distortion at the exit plane. To improve the flow uniformity, a single array of vortex generators （VGs） is employed within the inlet. In this experimental study, the effects of mass flow ratio, free stream Mach number, angle of attack and yaw on the performance of a serpentine inlet instrumented with VGs are obtained. Results indicate： （1） Compared with the baseline serpentine design without flow control, the application of the VGs promotes the mixing of core flow and the low momentum flow in the boundary layer and thus prevents the flow separation. Under the design condition, the exit flow distortion （-↑△σ0） decreases from 11.7% to 2.3% by using the VGs. （2） With the descent of the free stream Mach number the total pressure loss decreases. However, the circular total pressure distortion increases. When the angle of attack rises from - 4° to 8°, the total pressure recovery and the circular total pressure distortion both go down. In addition, with the increase of yaw the total pressure recovery is fairly constant, while the circular total pressure distortion ascends gradually. （3） When Mao = 0.6-0.8, a = -4°-8° and β = 0°-6°, the total pressure recovery varies between 0.936 and 0. 961, the circular total pressure distortion coefficient varies between 1.4 % and 5.4 % and the synthesis distortion coefficient has a ranges from 3.8 % to 7.0 %. The experimental results confirm the excellent performance of the newly designed serpentine inlet incorporating VGs.

Centrifuge model test of an irrigation-induced loess landslide in the Heifangtai loess platform, Northwest China

The Heifangtai platform in Northwest China is famous for irrigation-induced loess landslides.This study conducted a centrifuge model test with reference to an irrigation-induced loess landslide that occurred in Heifangtai in 2011.The loess slope model was constructed by whittling a cubic loess block obtaining from the landslide site.The irrigation water was simulated by applying continuous infiltration from back of the slope.The deformation,earth pressure,and pore pressure were investigated during test by a series of transducers.For this particular study,the results showed that the failure processes were characterized by retrogressive landslides and cracks.The time dependent reductions of cohesion and internal friction angle at basal layer with increasing pore-water pressure were responsible for these failures.The foot part of slope is very important for slope instability and hazard prevention in the study area,where concentration of earth pressure and generation of high pore-water pressures would form before failures.The measurements of earth pressure and pore-water pressure might be effective for early warning in the study area.

Geologically controlling factors on coal bed methane （CBM） productivity in Liulin

It is of great significance to forecast high yield of CBM wells and analyze dynamic production by having an overall study on the characteristics of the produced CBM and determining the main factors influencing the productivity of CBM. With the test report and the related geological parameters of a single well, methods of combining the productivity data and typical production curves were used to analyze different geological factors and how to influence the capacity of a single layer. Then, the paper proposed a new understanding about capacity characteristics of the study area and geological control factors： First, the Shanxi formation production capacity characteristics was divided into two-stages, showing signs of gas and gas break- through for 100 days. Second, two parameters, which include potential of gas production and gas production capacity, were bet- ter than the single parameter, such as gas content, coal thickness, and penetration to analyze affecting factors of single well pro- duction. Finally, comprehensive analysis concluded that the ratio of critical desorption pressure to reservoir pressure has greater influence on the production of vertical CBM wells. Besides, the potential of gas production capacity has greater impact at stage of showing gas signs; the coal reservoir pressure and gas production capacity have greater impact at stage of gas breakthrough for 100 days. Thus, to seek the coal bed methane with high ratio of critical desorption pressure to reservoir pressure and high yield of gas will be important guarantee to the success of the coal bed methane exploration and development.

A method of determining the permeability coefficient of coal seam based on the permeability of loaded coal

This study developed the equipment for thermo-fluid–solid coupling of methane-containing coal, and investigated the seepage character of loaded coal under different working conditions. Regarding the effective pressure as a variable, the variation characteristics of the gas permeability of loaded methane-containing coal has been studied under the conditions of different confining pressures and pore pressures. The qualitative and quantitative relationship between effective stress and permeability of loaded methane-containing coal has been established, considering the adsorption of deformation, amount of pore gas compression and temperature variation. The results show that the permeability of coal samples decreases along with the increasing effective stress. Based on the Darcy law, the correlation equation between the effective stress and permeability coefficient of coal seam has been established by combining the permeability coefficient of loaded coal and effective stress. On the basis of experimental data, this equation is used for calculation, and the results are in accordance with the measured gas permeability coefficient of coal seam. In conclusion, this method can be accurate and convenient to determine the gas permeability coefficient of coal seam, and provide evidence for forecasting that of the deep coal seam.

Formation Mechanism and Exhumation Processes for HP-UHP Metamorphic Rocks in Dabie Mountains

The high, ultrahigh pressure metamorphic rocks, widely distributed in Dabie Mountains, were described in terms of the geological setting, the marks of the petrology and the mineralogy of the ultrahigh pressure (UHP) metamorphic rocks. According to the estimated uplifting and denudation of the Dabie Mountains, and to the thermodynamics theory, were assessed the depth and pressure (high pressure autoclave) of the formation setting of the UHP metamorphic rocks. Based on all the information mentioned above, a new explanation is derived from the mechanism of formation and the processes of exhumation of the UHP metamorphic rocks.

Prediction of pulmonary arterial wedge pressure from arterial pressure or pulse oximetry plethysmographic waveform

Objective To assess the possibility of using arterial pressure waveform or pulse oximetry plethysmographic waveform variation to estimate the pulmonary arterial wedge pressure (PAWP) Methods Fourteen American Society of Anesthesiologists grade Ⅰ-Ⅱ patients aged 33-69 years and weighing 62 0±9 5 kg scheduled for elective abdominal tumor surgery were studied Their hemoglobin exceeded 120 g/L and hematocrit exceeded 35% Pre operative acute hypervolemic hemodilution was applied immediately after general anesthestic induction and tracheal intubation PAWP, systolic pressure variation (SPV), delta down (dDown), SPV plet , dDown plet and other hemodynamic parameters were measured and recorded when total fluid volume (crystalloid and colloid) infused reached 10 ml/kg and 20 ml/kg and again at the end of the operation Central venous pressure was maintained at 10-12 mm Hg during operation Systolic blood pressure at the end of Valsalva maneuver (airway pressure was kept at 22 mm Hg) and the systolic pressure before the Valsalva manoeuvre during apnea were used to calculate arterial pressure ratio (APR) Results APR, SPV, dDown, SPV plet and dDown plet all correlated well with PAWP ( r =0 717, -0 695, -0 680, -0 522 and -0 624 respectively, P <0 01) There was a closer linear correlation between APR and PAWP than between the other parameters The regression equation was PAWP (mm Hg)=0 207×APR (%)-0 382 Conclusion During positive pressure mechanical ventilation, APR, SPV, dDown, SPV plet and dDown plet can be used to estimate PAWP effectively

Effects of extrinsic positive end-expiratory pressure on cardiopulmonary function in patients with chronic obstructive pulmonary disease

Objective To choose one optimal extrinsic positive end-expiratory pressure (PEEPe) for ventilated patients with chronic obstructive pulmonary disease (COPD) and to compare two methods for choosing the optimal level of PEEPe.Methods Ten ventilated patients with COPD were included in the study. First, static intrinsic positive end-expiratory pressure (PEEPi,st) was measured when PEEPe was zero, and the PEEPi,st was called PEEPi,stz. PEEPe at 0%, 40%, 50%, 60%, 70%, 80%, 90% and 100% of PEEPi,stz, respectively, were applied randomly. Respiratory mechanics, hemodynamics, and oxygen dynamics were recorded 30 minutes after the level of PEEPe was changed.Results When PEEPe was not higher than 80% of PEEPi,stz, no measurement changed significantly. When PEEPe was increased to 90% and 100% of PEEPi,stz, PEEPi,st, peak inspiratory pressure, plateau pressure, pulmonary capillary wedge pressure and central venous pressure increased significantly, P<0.01. Cardiac output and left ventricular work index decreased significantly, P<0.01. Oxygen delivery decreased significantly, P<0.05. When PEEPe was increased to 100% of PEEPi,stz, the right ventricular work index decreased significantly, P<0.05.Conclusion Eighty percent of PEEPi,stz was the upper limit of PEEPe. The results of the two methods used to set the level of PEEPe were identical.

Low-cost and miniature all-silica Fabry–Perot pressure sensor for intracranial pressure measurement

The monitoring of increased intracranial pressure（ICP） is necessary in the diagnosis and treatment of patients with neurological disease because it can provide an insight into the mechanism of the head injury. In this letter, we develop a novel miniature Fabry–Perot（F-P） sensor for ICP measurement. The proposed sensor is fabricated by using a commercially available fusion splicer and a fiber cleaver, by which many difficult art problems involved in fabrication are solved and the online monitoring of the F-P cavity is actualized. The sensor exhibits a linear response to the applied pressure over the range of 0–25 k Pa（ample for ICP measurement）, with a sensitivity of 10.18 nm/k Pa, a resolution of 0.1 k Pa, and a reduced thermal sensitivity of 0.068 nm/°C, which shows it can meet the requirements of ICP measurement.

Comparison on Traditional and Machinery Decoctions for Da-cheng-qi Decoction Based on Chemical Ingredients, Pharmacological Functions, and Clinical Trials

Objective Patients and doctors often have questions about the equivalence of traditional and machinery decoctions. In this article, using Da-cheng-qi Decoction（DCQD） as a model of formula, traditional decoction（TD）, machinery decoction under high pressure（MDHP）, and machinery decoction under normal pressure（MDNP） were compared. Methods For chemical components, HPLC fingerprints were established and evaluated using AHP combined with CRITIC weighing method; For animals＇ effects, the experiments of small intestinal propulsion were conducted; For clinical effects, a randomized clinical trial（RCT） was designed and performed. Results Although there were some differences between TD and MDNP in chemical ingredients, there was no significant difference in animal experiments and clinical trials（P 〉 0.05）. Conclusion The traditional and machinery decoctions of DCQD could be used bioequivalently.