Development of a Novel Parallel-spool Pilot Operated High-pressure Solenoid Valve with High Flow Rate and High Speed

High-pressure solenoid valve with high flow rate and high speed is a key component in an underwater driving system.However,traditional single spool pilot operated valve cannot meet the demands of both high flow rate and high speed simultaneously.A new structure for a high pressure solenoid valve is needed to meet the demand of the underwater driving system.A novel parallel-spool pilot operated high-pressure solenoid valve is proposed to overcome the drawback of the current single spool design.Mathematical models of the opening process and flow rate of the valve are established.Opening response time of the valve is subdivided into 4 parts to analyze the properties of the opening response.Corresponding formulas to solve 4 parts of the response time are derived.Key factors that influence the opening response time are analyzed.According to the mathematical model of the valve,a simulation of the opening process is carried out by MATLAB.Parameters are chosen based on theoretical analysis to design the test prototype of the new type of valve.Opening response time of the designed valve is tested by verifying response of the current in the coil and displacement of the main valve spool.The experimental results are in agreement with the simulated results,therefore the validity of the theoretical analysis is verified.Experimental opening response time of the valve is 48.3 ms at working pressure of 10 MPa.The flow capacity test shows that the largest effective area is 126 mm2 and the largest air flow rate is 2320 L/s.According to the result of the load driving test,the valve can meet the demands of the driving system.The proposed valve with parallel spools provides a new method for the design of a high-pressure valve with fast response and large flow rate.

Polymer-Based Micro Flow Sensor with Alternative Electronic Signal Interfaces for Low and High Flow Rates

The qualitative and quantitative assessment of gas flow has become increasingly relevant in the use of everyday systems. The micro flow sensor, developed by Innovative Sensor Technology AG （Switzerland）, is by principle a calorimetric flow sensor produced as a micro system on a glass substrate by means of photolithography and glass etching technology. These structures are arranged as a platinum micro heater and sensor in a Wheatstone bridge. The subsequent etching process produces an exposed area of polyimide membrane that is only a few microns thick and includes the resistive sensor structure as the active area. In addition, the RTD （resistance temperature detector） technology included on the sensor allows for the implementation of a variety of electronic biasing and signal processing modes. Since the sensor can be powered and the bridge can be measured in both CTA （constant temperature anemometer） and calorimetric mode, new possibilities are presented for both low and high flow rates with regard to temperature compensation, self-calibration and self-monitoring.

Electrical Resistivity Contrasts and High Flow Rates Discontinuous Aquifers Identification in a Sheared Crystallophyllian Basement Zone at Boniérédougou (North-Central Côte d’Ivoire)

This study proposes an alternative approach to the investigation of high flow hydrogeological fractures within the basement in the Dabakala region of north-central Côte d’Ivoire. The used approach consists of exploring the subsurface by measuring electrical resistivity contrasts along the main shear direction within crystallophyllian rocks. Electrical resistivity profiling and vertical electrical sounding techniques, coupled with boreholes monitoring, have identified fractured aquifers whose best flow rates are around 96 and 116 m3/h. These aquifers mostly hosted in granodiorite have an average strength of 10 meters and are located at depth of around 100 meters. They are associated with open fractures created by tangential shear stresses that have affected the Dabakala volcano-sedimentary trench formations. The search for fractured aquifers along the main shear direction offers great perspective for obtaining high flow rates.

High-flow priapism due to bilateral cavernous artery fistulas treated by unilateral embolization:A case report

BACKGROUND High flow priapism(HFP)is a rare type of priapism.Perineal trauma is the most common cause of HFP.Trauma-induced penile artery injury may lead to an arterial-cavernosal fistula,whereas persistent irregular arterial blood flow entering the corpora cavernosum can cause a persistent penile erection.The routine treatment of HFP focuses on addressing the abnormal penile erectile status and avoiding post-treatment erectile dysfunction.Interventional embolization is an important therapeutic modality for HFP,and bilateral embolization therapy is currently the most commonly used technique for patients with bilateral cavernous artery fistulas;however,unilateral embolization therapy has yet to be reported.CASE SUMMARY Herein,we report of the case of a 26-year-old Chinese male who presented with a persistent abnormal erection for 12 h after perineal impact injury.Medical history,cavernous arterial blood gas analysis and radiological examinations led to a diagnosis of HFP caused by bilateral cavernous artery fistulas.We performed routine conservative treatment(compression therapy and ice application)for the patient after admission;however,10 d later,his symptoms had not been relieved.After completion of the preoperative workup,right(severe side)selective perineal artery embolization was performed;the left cavernous artery fistula was left untreated.After postoperative continuation of conservative treatment for 72 h,the patient experienced complete penile thinning.The patient had no symptoms of erectile dysfunction over a follow-up period of 12 mo.CONCLUSION Compared with bilateral cavernous artery fistula embolization,we believe that unilateral cavernous artery fistula embolization can achieve positive clinical efficacy and reduce the risk of postoperative erectile dysfunction secondary to penile ischemia.

Impact and Management under Extracorporeal Circulation of a Patient with Renal Insufficiency on Dialysis with a High-Flow Arteriovenous Fistula in the Cardiac Surgery Department of the Angers Teaching Hospital about a Case and Review of the Literature

Arteriovenous fistulas have a substantial impact on systemic hemodynamics, however their effect on extracorporeal circulation is not well understood. We report our clinical observation on the management under extracorporeal circulation of a patient with renal insufficiency with a high-flow arteriovenous fistula. This is a 59-year-old man who was referred to us for surgical treatment of ischemic coronary artery disease in a context of anuric chronic renal failure. Hypothermia at 32°C is started from the start in CEC due to hyperflow at the level of the arteriovenous fistula. We performed two coronary artery bypasses of the marginal and IVA via the two internal thoracic arteries. The patient is hemofiltered in order to avoid hyperkalaemia and possibly avoid fluid overload related to filling per CEC. The clamping time was 71 minutes and the SCC lasted 141 minutes. There was no homologous transfusion in the operating room. It turns out that the input/output balance is zero at the end of the CEC. The postoperative course was simple.

Study on Characteristics of a High-Precision Cold Gas Micro Thruster

In order to improve the reliability of the spacecraft micro cold gas propulsion system and realize the precise control of the spacecraft attitude and orbit, a micro-thrust, high-precision cold gas thruster is carried out, at the same time due to the design requirements of the spacecraft, this micro-thrust should be continuous working more than 60 minutes, the traditional solenoid valve used for the thrusts can’t complete the mission, so a long-life micro latching valve is developed as the control valve for this micro thruster, because the micro latching valve can keep its position when it cuts off the outage. Firstly, the authors introduced the design scheme and idea of the thruster. Secondly, the performance of the latching valve and the flow characteristics of the nozzle were simulated. Finally, from the experimental results and compared with the numerical study, it shows that the long-life micro cold gas thruster developed in this paper meets the mission requirements.

High-flow nasal oxygen availability for sedation decreases the use of general anesthesia during endoscopic retrograde cholangiopancreatography and endoscopic ultrasound

AIM To examine whether high-flow nasal oxygen(HFNO) availability influences the use of general anesthesia(GA) in patients undergoing endoscopic retrograde cholangiopancreatography(ERCP) and endoscopic ultrasound(EUS) and associated outcomes.METHODS In this retrospective study, patients were stratified into 3 eras between October 1, 2013 and June 30, 2014 based on HFNO availability for deep sedation at the time of their endoscopy. During the first and last 3-mo eras(era 1 and 3), no HFNO was available, whereas it was an option during the second 3-mo era(era 2). The primary outcome was the percent utilization of GA vs deep sedation in each period. Secondary outcomes included oxygen saturation nadir during sedation between periods, as well as procedure duration, and anesthesia-only time between periods and for GA vs sedation cases respectively.RESULTS During the study period 238 ERCP or EUS cases were identified for analysis. Statistical testing was employed and a P < 0.050 was significant unless the Bonferroni correction for multiple comparisons was used. General anesthesia use was significantly lower in era 2 compared to era 1 with the same trend between era 2 and 3(P = 0.012 and 0.045 respectively). The oxygen saturation nadir during sedation was significantly higher in era 2 compared to era 3(P < 0.001) but not between eras 1 and 2(P = 0.028) or 1 and 3(P = 0.069). The procedure time within each era was significantly longer under GA compared to deep sedation(P ≤ 0.007) as was the anesthesia-only time(P ≤ 0.001).CONCLUSION High-flow nasal oxygen availability was associated with decreased GA utilization and improved oxygenation for ERCP and EUS during sedation.

Performance analysis and improvement of a high flow coefficient centrifugal compressor

Very high flow coefficient centrifugal compressor stages are mostly performance of this type of stages is critical to the entire centrifugal applied as the first stages of multistage compressors. The compressors, but surprisingly little related information is available in the open literature. A centrifugal compressor with high inlet flow coefficient of 0.2, presenting a narrow operating range and unstable running situation even at design speed during the test, is investigated here. To reveal flow details in this centrifugal compressor, numerical simulations have been carried out and indicate that excessive impeller flow diffusion results in the poor performance of this centrifugal compressor. With the same inlet flow coefficient, six redesign cases coming from an in-house one-dimensional analysis program are proposed together with impeller trimming and equal flow area design method for corresponding vaneless diffuser. Performance comparison among these redesign centrifugal compressors is presented and the most suitable one is recommended for test in the future. In addition, three redesign cases with lower inlet flow coefficient developed by means of flow trimming are shown in the end to satisfy potential application areas. Finally, the results in this study can provide valuable reference information for multistage centrifugal compressor design.

High-flow nasal cannula oxygen therapy during anesthesia recovery for older orthopedic surgery patients: A prospective randomized controlled trial

BACKGROUND Hypoxemia is a common complication in older patients during postoperative recovery and can cause pulmonary complications.Therefore,reducing the incidence of postoperative hypoxemia is a clinical concern.AIM To investigate the clinical efficacy of high-flow nasal cannula oxygen(HFNCO)in the resuscitation period of older orthopedic patients.METHODS In this prospective randomized controlled trial,60 older patients who underwent orthopedic surgery under general anesthesia were randomly divided into two groups:those who used conventional face mask and those who used HFNCO.All patients were treated with 60%oxygen for 1 h after extubation.Patients in the conventional face mask group were treated with a combination of air(2 L)and oxygen(2 L)using a traditional mask,whereas those in the HFNCO group were treated with HFNCO at a constant temperature of 34℃ and flow rate of 40 L/min.We assessed the effectiveness of oxygen therapy by monitoring the patients’arterial blood gas,peripheral oxygen saturation,and postoperative complications.RESULTS The characteristics of the patients were comparable between the groups.One hour after extubation,patients in HFNCO group had a significantly higher arterial partial pressure of oxygen(paO_(2))than that of patients in conventional face mask group(P<0.001).At extubation and 1 h after extubation,patients in both groups showed a significantly higher arterial partial pressure of carbon dioxide(paCO_(2))than the baseline levels(P<0.001).There were no differences in the saturation of peripheral oxygen,paO_(2),and paCO_(2) between the groups before anesthesia and before extubation(P>0.05).There were statistically significant differences in paO_(2) between the two groups before anesthesia and 1 h after extubation and immediately after extubation and 1 h after extubation(P<0.001).However,there were no significant differences in the oxygen tolerance score before leaving the room,airway humidification,and pulmonary complications 3 d after surgery between the two groups(P>0.05).CONCLUSION HFNCO can improve oxygen partial pressure and respiratory function in elderly patients undergoing orthopedic surgery under general endotracheal anesthesia.Thus,HFNCO can be used to prevent postoperative hypoxemia.

Assessment of climate change impact on high flows in a watershed characterized by flood regulating reservoirs

A climate-induced extreme flow event such as flooding is one of the most devastating natural hazards,which can significantly damage human lives and properties.This study examined the effects of climate change on the high flow conditions in the Great Miami River Watershed in Ohio under two emission scenarios(RCP 4.5 and RCP 8.5).Streamflow for the 21st century was simulated by utilizing a watershed model-SWAT(Soil and Water Assessment Tool)and 10 different climate outputs from the Coupled Model Intercomparison Project phase 5(CMIP5).The future streamflow was divided into three equal periods:2016-2043(early century),2044-2071(mid-century),and 2072-2099(late century)and independently analyzed to compare high flows of respective intervals with baseline periods(1988-2015).The analysis predicted that 7-day,10-year high-flow(7Q10)would increase by 38%under RCP 4.5 and 44%under RCP 8.5.Similarly,the annual peak flows for study periods were predicted to increase by 26%under RCP 4.5 and 38%under RCP 8.5 from the base period.However,the analysis demonstrated an erratic response for monthly peaks indicating that the peak flow would increase in summer months-May and July to October.Meanwhile,the result did not show any significant increase during the winter season,especially from November to April.The analysis of the four major dams located in the watershed showed that the dam’s peak discharges increase in January,May,and September.Even though increasing peaks were projected in September for the 21st century,the monthly peaks from the watershed outlet were found to be lowest in September as compared to other months.The frequency of future flooding compared to the historical record was found to be increasing in the mid-century under RCP 4.5 and the late century under RCP 8.5.As the future flood is projected to increase,this study finds the reasonable impact of climate change on flood regulating reservoirs/dams in monthly flows.However,daily high flows(90th percentile flow)would be increasing significantly(44%to 250%)under RCP 8.5.

基于GO-FLOW法的某高速列车齿轮箱可靠性分析方法研究

针对传统FTA无法对有反馈、多状态、有时序系统进行可靠性计算的问题,提出了一种基于GO-FLOW法的某型高速列车变速箱的可靠性分析方法。首先,根据齿轮箱的工作原理和结构逻辑,确定了操作符的类型并建立了齿轮箱系统的GO-FLOW图模型。其次,修正共因故障后计算齿轮箱成功概率并绘制齿轮箱的健康变化规律曲线。最后,对比GO-FLOW与FTA的分析结果可知,GO-FLOW法在齿轮箱健康评估应用中高效可行,且具有时序性。同时,该方法减少了计算量,为维修维护高速列车齿轮箱系统和提升其健康管理水平提供了一定的理论指导作用。

End-of-life home care of an interstitial pneumonia patient supported by high-flow nasal cannula therapy:A case report

BACKGROUND High-flow nasal cannula(HFNC)therapy and morphine continuous subcutaneous infusion(CSI)have been used to ameliorate dyspnea in non-cancer patients with end-stage respiratory diseases,including chronic obstructive pulmonary disease and interstitial pneumonia,primarily in hospital settings.However,it is rare to perform home-based medical treatment using these.We observe a case to assess the feasibility of this treatment strategy.CASE SUMMARY Here,we report a case of a 75-year-old man who was diagnosed with interstitial pneumonia 11 years ago and was successfully nursed at home during his terminal phase for over 10 mo without hospitalization,by introducing domiciliary uses of HFNC and morphine CSI with a patient-controlled analgesia device.CONCLUSION Active utilization of HFNC and morphine CSI with patient-controlled analgesia device would substantiate successful end-of-life palliative home care of idiopathic interstitial pneumonia patients.

NONPARALLEL BOUNDARY LAYER STABILITY IN HIGH SPEED FLOWS

The parabolized stability equations （PSEs） for high speed flows, especially supersonic and hypersonic flows, are derived and used to analyze the nonparallel boundary layer stability. The proposed numerical techniques for solving PSE include the following contents： introducing the efficiently normal transformation of the boundary layer, improving the computational accuracy by using a high-order differential scheme near the wall, employing the predictor-corrector and iterative approach to satisfy the important normalization condition, and implementing the stable spatial marching. Since the second mode dominates the growth of the disturbance in high Mach number flows, it is used in the computation. The evolution and characteristics of the boundary layer stability in the high speed flow are demonstrated in the examples. The effects of the nonparallelizm, the compressibility and the cooling wall on the stability are analyzed. And computational results are in good agreement with the relevant data.

The relationship between ENSO cycle and high and low-flow in the upper Yellow River

Firstly, the hydrological and meteorological features of the upper reaches of the Yellow River above Tangnag are analyzed based on observation data, and effects of EI Nino and La Ni na events on the high and low flow in the upper Yellow River are discussed. The results show El Nino and La Nina events possess consanguineous relationship wi th runoff in the upper Yellow River. As a whole, the probability of low fl ow occurrence in the upper Yellow River is relatively great along wit h the occurrence of El Nino event. Moreover, the flood in the upper Yellow River occurs frequently with the occurrence of La Nina event. Besides, the results also show dissimilarity of El Nino event occurri ng time exerts greater impact on high flow and low flow in the uppe r Yellow River, that is, the probability of drought will be greater in the sam e year if El Nino event occurs in spring, the high-flow may happen in this y ear if El Nino occurs in summer or autumn; the longer the continuous period of El Nino is, the lower the runoff in the upper Yellow River is.

A study of hydrate plug formation in a subsea natural gas pipeline using a novel high-pressure flow loop

The natural gas pipeline from Platform QKI8-1 in the southwest of Bohai Bay to the onshore processing facility is a subsea wet gas pipeline exposed to high pressure and low temperature for a long distance. Blockages in the pipeline occur occasionally. To maintain the natural gas flow in the pipeline, we proposed a method for analyzing blockages and ascribed them to the hydrate formation and agglomeration. A new high-pressure flow loop was developed to investigate hydrate plug formation and hydrate particle size, using a mixture of diesel oil, water, and natural gas as experimental fluids. The influences of pressure and initial flow rate were also studied. Experimental results indicated that when the flow rate was below 850 kg/h, gas hydrates would form and then plug the pipeline, even at a low water content （10%） of a water/oil emulsion. Furthermore, some practical suggestions were made for daily management of the subsea pipeline.

ASYMMETRIC VORTICES FLOW OVER SLENDER BODY AND ITS ACTIVE CONTROL AT HIGH ANGLE OF ATTACK

The studies of asymmetric vortices flow over slender body and its active control at high angles of attack have significant importance for both academic field and engineering area.This paper attempts to provide an update state of art to the investigations on the fields of forebody asymmetric vortices.This review emphasizes the correlation between micro-perturbation on the model nose and its response and evolution behaviors of the asymmetric vortices.The critical issues are discussed, which include the formation and evolution mechanism of asymmetric multi-vortices;main behaviors of asymmetric vortices flow including its deterministic feature and vortices flow structure;the evolution and development of asymmetric vortices under the perturbation on the model nose;forebody vortex active control especially discussed micro-perturbation active control concept and technique in more detail.However present understanding in this area is still very limited and this paper tries to identify the key unknown problems in the concluding remarks.

Sleep Quality for Patients Receiving Noninvasive Positive Pressure Ventilation and Nasal High-Flow Oxygen Therapy in an ICU: Two Case Studies

Aim: The purpose of this case study was to examine the sleep quality of patients receiving noninvasive positive pressure ventilation (NPPV) or nasal high-flow oxygen therapy (NHF) in an intensive care unit and to investigate what types of nursing support are offered to such patients. Methods: We examined one patient each for NPPV and NHF. Polysomnography (PSG), review of the patient charts, and semi-structured interviews were used to collect the data for analysis. Results: Patients treated with NPPV or NHF demonstrated a noticeable reduction in deep sleep, with most of their sleep being shallow. Their sleep patterns varied greatly from those of healthy individuals. These results suggest that, in addition to experiencing extremely fragmented sleep, sleep in these patients was more likely to be interrupted by nursing interventions, such as during auscultation of breath sounds. Furthermore, it was revealed that “anxiety or discomfort that accompanies the mask or air pressure” in patients treated with NPPV and “discomfort that accompanies the nasal cannula or NHF circuit” in patients treated with NHF may be primary causes of disrupted sleep. Our results suggest a need for nursing care aimed at improving sleep quality in patients treated with NPPV or NHF.

Residence time distribution of high viscosity fluids falling film flow down outside of industrial-scale vertical wavy wall: Experimental investigation and CFD prediction

The flow behavior of gravity-driven falling film of non-conductive high viscosity polymer fluids on an industrial-scale vertical wavy wall was investigated in terms of film thickness and residence time distribution by numerical simulation and experiment.Falling film flow of high viscosity fluids was found to be steady on a vertical wavy wall in the presence of the large film thickness.The comparison between numerical simulation and experiment for the film thickness both in crest and trough of wavy wall showed good agreement.The simulation results of average residence time of falling film flow with different viscous fluids were also consistent with the experimental results.This work provides the initial insights of how to evaluate and optimize the falling film flow system of polymer fluid.

Effect of turbulent flow on electromagnetic elimination with high frequency magnetic field

The results of experiments and simulations show that there is a turbulent flow in the molten aluminum and it is hard to be restrained in the thin tubule (diameter of 6 mm) when the electromagnetic body force is applied. The electromagnetic elimination experimental results show that the flow has serious effect on the elimination of 5 μm alumina inclusions, but has little effect on the 30 μm and 100 μm primary silicon. The effects of the electromagnetic field and the turbulent flow on the electromagnetic elimination are discussed.

CONJUGATE MODEL FOR HEAT AND MASS TRANSFER OF POROUS WALL IN THE HIGH TEMPERATURE GAS FLOW

Heat and mass transfer of a porous permeable wall in a high temperature gas dynamical flow is considered. Numerical simulation is conducted on the ground of the conjugate mathematical model which includes filtration and heat transfer equations in a porous body and boundary layer equations on its surface. Such an approach enables one to take into account complex interaction between heat and mass transfer in the gasdynamical flow and in the structure subjected to this flow. The main attention is given to the impact of the intraporous heat transfer intensity on the transpiration cooling efficiency.