Pressure Rate Changes Research Articles

Improving internal fluid stability of pump turbine in load rejection process by co-adjusting inlet valve and guide vane

Pumped storage plant(PSP) is a high efficient emission-free technology to balance the unstable electricity generation from renewable energy. In order to meet the variable requirements from power grid, the pumped storage units need to change working conditions frequently and quickly. Pump turbines have to run in transient processes, which stability affects safe operation of PSP directly. The load rejection of pump turbine is studied in this work, wherein the coordinated regulation of valve and guide vane is applied in this transition. This work aims at increasing the internal fluid stability of pump turbine, by reducing the change rate of pressure and improving flow regime. The combination of theoretical analysis and numerical simulation is the main research method, wherein wall sliding mesh technique is used to achieve continuous movements of valve core and guide vanes. Detached eddy simulation is adopted to solve the transient flow field, the fluid is characterized by a series of parameters like turbulent kinetic energy, pressure fluctuation and vortex evolution, etc. The results prove that a great contribution made by this co-adjusting method, it is beneficial to operation stability of system, especially for the final phase of load rejection.

The brake pressure change rate in brake chamber and its online monitoring in semitrailer transport vehicle for dangerous cargo

The electronically controlled pneumatic brake system (ECPBS) of semitrailer transport vehicle for dangerous cargo (STVDC) is required to control the brake pressure in each brake chamber accurately and stably. Accordingly, the brake pressure change rate (BPCR) in the brake chamber is taken as one of the evaluation parameters and control indicators of ECPBS for STVDC in this paper; an online monitoring implementation scheme of the BPCR in the brake chamber is designed; a simplified model is built based on AMESim and verified by hardware-in-the-loop experiments based on dSPACE; finally, the online monitoring function of BPCR in the brake chamber is validated with the simplified model. This paper provides a new idea for the design and development of ECPBS for STVDC.

Research on Measurement Principle and Key Measuring Devices of Pressure Change Rate for Electronically Controlled Pneumatic Brake of Commercial Vehicle Based on Poiseuille's Law.

For intelligence brakes in the electronic pneumatic brake system of commercial vehicles, the pressure change rate is used as the key control parameter and evaluation index. This can improve the brake safety, stability, and ride comfort of the vehicle. The real-time detection of the brake pressure change rate for commercial vehicles is the premise for realizing the accurate control of brake pressure change rate. Based on Poiseuille’s law, an efficient measurement method of brake pressure change rate is proposed for commercial vehicles, and a new measuring device with an isothermal container and laminar flow resistance tube as the core components is designed. Through thermal insulation performance tests, flow resistance tests and measurement accuracy tests, combined with simulations, the effects of structural parameters and copper wire filling density on the performance of the isothermal container are analyzed, and these key parameters are optimized to improve the thermal insulation performance. A tubular laminar flow resistance tube composed of 304 stainless steel capillaries in parallel is designed. The influence mechanism of core parameters such as the number, radius, and length of laminar flow channels on its performance is studied, and the optimal parameter array is selected to optimize its performance. The experimental platform for measuring brake pressure change rate is constructed. By comparing the measurement curve of brake pressure change rate under simulation and experiment, the correctness and effectiveness of the pressure change rate measurement principle and the key components for electronically controlled pneumatic brakes of commercial vehicles are verified to meet engineering requirements.

Heat and mass transfer and hydrodynamics in cryogenic hydrogen fuel systems

The paper presents the results of experimental and theoretical studies and the development of methods to calculate the parameters of heat and mass transfer as well as hydrodynamic processes occurring during the following operations: filling of reservoirs and tanks with LH2; drain-free storage of LH2; saturation of LH2 with non-condensable gas (helium) during tank pressurization; drainage of hydrogen vapors and displacement of LH2 from the storage tank. It is noted that the main design parameters characterizing the process of filling cryogenic reservoirs and tanks are the following: the time of filling to the required level; LH2 evaporation losses during cooling; thermal stresses in the walls of reservoirs and tanks. The time of LH2 drain-free storage in real reservoirs and tanks is reduced due to thermal stratification in the liquid and gas–vapor phases compared to the time of LH2 drain-free storage under conditions of its complete mixing. The drainage of LH2 vapors is characterized by the following main design parameters: the rate of pressure change in the cryogenic tank; the flow rate of the drained mass; the degree of non-equilibrium during LH2 boiling; drop entrainment; an increase in the LH2 volume during boiling (“swelling”); the degree of pressure increase in case of a sudden termination of drainage. When LH2 is displaced, the following parameters of the feed system have a decisive influence on the heat and mass transfer characteristics: displacement pressure; LH2 thermal stratification; the degree of LH2 saturation with non-condensable gas; the maximum temperature of the tank wall; the mass of pressurizing gas. Liquid hydrogen (LH2) can be saturated during pressurization and displacement with helium and during other operations involving the use of non-condensable gas. The process of LH2 saturation with pressurizing gas (helium) is characterized by the following parameters: absorption coefficient that determines the efficiency of gas saturation and is equal to the ratio of the dissolved amount of helium to the entire mass of non-condensable gas that has passed through the solution; change in the LH2 temperature during gas saturation; helium concentration in the solution and its homogeneity. Based on the obtained experimental data and mathematical modeling, we determined relationships that make it possible to calculate the listed main parameters of heat and mass transfer as well as hydrodynamic processes at the main stages of the design and operation of cryogenic hydrogen tanks, systems of LH2 storage and feeding. The presented relationships can be used as reference data in the design and optimization of LH2 fuel systems.

Understanding Complex Interactions in Pediatric Diastolic Function Assessment

Diagnosing left ventricular diastolic dysfunction (DD) noninvasively in children is difficult as no validated pediatric diagnostic algorithm is available. The aim of this study is to explore the use of machine learning to develop a model that uses echocardiographic measurements to explain patterns in invasively measured markers of DD in children. Children at risk for developing DD were enrolled, including patients with Kawasaki disease, heart transplantation, aortic stenosis, and coarctation of the aorta when undergoing clinical left heart catheterization. Simultaneous invasive pressure measurements were made using a high-fidelity catheter (time constant of isovolumic relaxation [Tau, τ], left ventricular end-diastolic pressure, and maximum negative rate of pressure change) and echocardiographic DD measurements. Spearman correlations were performed for each echocardiographic feature with invasive markers to understand pairwise relationships. Separate random forest (RF) models were implemented to assess all echocardiographic features, key demographic data, and clinical diagnosis in predicting invasive markers. A backward stepwise regression model was simultaneously implemented as a comparative conventional reference model. The relative importance of all parameters was ranked in terms of accuracy reduction. Model approximation was then performed using a regression tree with the top-ranked features of each RF model to improve model interpretability. Regression coefficients of the linear models were presented. Fifty-nine children were included. Spearman correlations were generally low. The RF models' performance measures were noninferior to those of the linear model. However, the linear model's regression coefficients were unintuitive. The highest ranked important features for the RF models were propagation velocity for Tau, E/propagation velocity ratio for left ventricular end-diastolic pressure, and systolic global longitudinal strain rate for maximum negative rate of pressure change. Estimating individual components of DD can potentially improve the noninvasive assessment of pediatric DD. Although pairwise correlations measured were weak and linear regression coefficients unintuitive,approximated machine learning models aided in understanding how echocardiographic and invasive parameters of DD are related. This machine learning approach could help in further development of pediatric-specific diagnostic algorithms.

High-Flow Nasal Cannula Reduces Effort of Breathing But Not Consistently via Positive End-Expiratory Pressure

High-flow nasal cannula (HFNC) therapy reduces the effort of breathing in patients with bronchiolitis, but the mechanisms are not understood. Theorized mechanisms include dead space washout and positive end-expiratory pressure (PEEP) application. What are the mechanisms of action of HFNC therapy in patients with bronchiolitis? Prospective, single-center study of children 3 years of age or younger with bronchiolitis from January 2020 through March 2021. Flow was titrated between 0.5 and 2 L/kg/min. Electrical impedance tomography measured end-expiratory lung impedance (EELZ) change as an end-expiratory lung volume (EELV) change surrogate and change in tidal impedance difference (ΔZ) as a tidal volume (VT) surrogate. A subset showed manometry measuring esophageal pressure change (ΔPes; transpulmonary pressure surrogate) and pressure rate product (PRP; effort of breathing metric). We hypothesized that EELV and VT would not change and that effort would reduce via respiratory rate (not ΔPes). Measurements were reported as the difference from 0.5 L/kg/min. We studied 22 patients in total, 10 with esophageal manometry. Median EELZ increased by 0.36 arbitrary unit (AU), 2.42 AU, and 4.8 AU at 1 L/kg/min, 1.5 L/kg/min, and 2 L/kg/min (P= .01, 2 L/kg/min vs0.5 L/kg/min), which corresponded to a median increase in EELV of 1.8mL/kg between 0.5 and 2 L/kg/min. Seven patients showed an increase in EELZ of > 5 AU, 12 showed no change in EELZ (± 5 AU), and three showed a decrease in EELZ of > 5 AU. ΔZ (ie, VT) did not change from 0.5 L/kg/min to 2 L/kg/min (median change, 0.29 AU; P= .48). Median PRP decreased by 78cm H2O/min from 0.5 L/kg/min to 2 L/kg/min (P= .02), with all patients demonstrating a reduction in PRP, with a nonsignificant change in ΔPes (P= .68). Increasing HFNC in children with bronchiolitis reduces the effort of breathing, but no consistent increase occurs in end-expiratory lung volume and no significant change occurs in VT or transpulmonary pressure. This suggests that PEEP application is not the primary mechanism of action of HFNC in children with bronchiolitis.

지속적인 신체활동에 참여하는 당뇨와 고혈압자들을 위한 생활습관 개선 프로그램의 적용 사례 연구

This study was conducted to apply the life style improvement program for adult men with diabetes and hypertension people who participate in continuous physical activities. And to case study was conducted to suggest management method. The subjects of this study were two middle-aged men, who participated in the life style improvement program for one year, and measured the change rate of glucose and HbA1c, blood pressure and in depth counseling, the following conclusions were obtained. In the change rate of body composition, weight decreased by 3.26, 3,24%, and 2.93%, BMI decreased by 3.13%, 3.23%, and 3.75%, and body fat decreased by 4.9%, 7.22%, and 19.44%. WHR decreased by 3.57%, 1.23%, and 1.25%. In the change rate of glucose and HbA1c, glucose decreased by 14.80%, 8.50%, and 2.53%, and HbA1c decreased by 9.97%, 4.20%, and 0.79%. In the change rate of blood pressure, systolic blood pressure decreased by 11.16%, 12.19%, and 10.56% and diastolic blood pressure decreased by 11.86%, 0.28%, and 11.76%. In the in-depth counseling, Subjects A was said to be the main cause of “cardiovascular family history, large amount of drinking and lack of sleep, and stress that could not control the disease”, and Subjects B was not managed as a cause of “carnivorous and smoking”. In conclusion, the health care of adult men with life style diseases is not only managed for a short period of time or one thing, but also can be effectively managed by participating in a continuous and comprehensive life style improvement program.

Protective effects of 5(S)-5-carboxystrictosidine on myocardial ischemia-reperfusion injury through activation of mitochondrial KATP channels

5(S)-5-carboxystrictosidine (5-CS) is a compound found in Mappianthus iodoides Hand.-Mazz., root, a traditional Chinese medicine used for the treatment of coronary artery disease. In this study, we investigated whether 5-CS protects heart against I/R injury. Sprague–Dawley rats were treated with 5-CS intraperitoneally for 7 days before the experiment. Hearts were perfused for 20 min global ischemia and 180 min reperfusion. 5-CS significantly inhibited an increase in the post-ischemic left ventricular end-diastolic pressure (LVEDP) and improved the post-ischemic left ventricular developed pressure (LVDP), dP/dt maximum and dP/dt minimum rates of pressure change, and coronary flow as compared with sham group. Pretreatment with 5-hydroxydecanoic acid (5-HD), an inhibitor of mitochondrial KATP channel, for 10 min before ischemia attenuated the improvement of LVEDP, LVDP, dP/dt maximum and dP/dt minimum rates of pressure change, and coronary flow induced by 5-CS. 5-CS markedly decreased the infarct size and attenuated the increased lactate dehydrogenase (LDH) level in effluent during reperfusion. Pretreatment with 5-HD also blocked these protective effects of 5-CS. 5-CS increased Mn-SOD, catalase, and HO-1 levels decreased by I/R injury and pretreatment of 5-HD blocked the 5-CS effects. Increases in Bax, cleaved caspase-3 and cytochrome c levels, caspase-3 and caspase-9 activity, and decrease in Bcl-2 level by I/R injury were attenuated by 5-CS treatment and pretreatment of 5-HD blocked its effects. These results suggest that the protective effects of 5-CS against myocardial I/R injury may be partly related to activating antioxidant enzymes and suppressing apoptosis through opening mitochondrial KATP channels.

Methane emission dynamics from a Danish landfill: The effect of changes in barometric pressure.

This study investigates temporal variability on landfill methane (CH4) emissions from an old abandoned Danish landfill, caused by the rate of changes in barometric pressure. Two different emission quantification techniques, namely the dynamic tracer dispersion method (TDM) and the eddy covariance method (EC), were applied simultaneously and their results compared. The results showed a large spatial and temporal CH4 emission variation ranging from 0 to 100kgh-1 and 0 to 12μmol m-2 s-1, respectively. Landfill CH4 emissions dynamics were influenced by two environmental factors: the rate of change in barometric pressure (a strong negative correlation) and wind speed (a weak positive correlation). The relationship between CH4 emissions and the rate of change in barometric pressure was more complicated than a linear one, thereby making it difficult to estimate accurately annual CH4 emissions from a landfill based on discrete measurements. Furthermore, the results did not show any clear relationship between CH4 emissions and ambient temperature. Large seasonal variations were identified by the two methods, whereas no diurnal variability was observed throughout the investigated period. CH4 fluxes measured with the EC method were strongly correlated with emissions from the TDM method, even though no direct relationship could be established, due to the different sampling ranges of the two methods and the spatial heterogeneity of CH4 emissions.

Operating Modes Management of Oil and Oil Produkt Transport Systems Pipeline Assording to Acceptable Risk-Based Criterion

The paper discusses the solution to the problem of advanced risk management of oil and petroleum product pipeline systems (PS) based on calculating the level of stress-strain state of pipeline structures and reducing safety factors depending on the magnitude, rate, and frequency of pressure changes in the PS. The operating modes of some pipeline systems are characterized by unsteadiness, accompanied by an increased level and frequent changes in the pipe wall stresses and, as a result, increased accident risks. The pipeline systems operating in an unsteady mode include the main oil and petroleum product pipelines (MP), characterized by very long distances. In this case, possible damages to the linear MP parts cause significant loss. Therefore, despite the high reliability of these structures, maintaining an acceptable level of safety margins and the risk of accidents is a rather urgent problem. The risks of accidents are calculated using models linking the process parameters of the PS operating modes and their design characteristics with the permissible stresses in the pipe wall and the pipeline valve installation places.

Dynamic Characteristics of Unsteady Aerodynamic Pressure on an Enclosed Housing for Sound Emission Alleviation Caused by a Passing High-Speed Train

Train speed is increasing due to the development of high-speed railway technology. However, high-speed trains generate more noise and discomfort for residents, enclosed housing for sound emission alleviation is needed to further reduce noise. Because these enclosed housings for sound emission alleviation restrain the air flow, strong and complicated aerodynamic pressures are generated inside the housing for sound emission alleviation when a train passes through at a high speed. This train-induced aerodynamic pressure, particularly its dynamic characteristics, is a key parameter in structural design. In the present study, the train-induced unsteady aerodynamic pressure in an enclosed housing for sound emission alleviation is simulated using the dynamic mesh method, and the dynamic characteristics of the aerodynamic pressure are investigated. The simulation results show that when the train is running in the enclosed housing for sound emission alleviation, the unsteady aerodynamic pressure is complicated and aperiodic, and after the train leaves the housing for sound emission alleviation, the aerodynamic pressure reverts to periodic decay curves. Two new terms, the duration of the extreme aerodynamic pressure and the pressure change rate, are proposed to evaluate the dynamic characteristics when the train passes through the barrier. The dominant frequency and decay rate are adopted to express the dynamic characteristics after the train exits. When the train runs in the enclosed housing for sound emission alleviation, the longest durations of the positive and negative extreme aerodynamic pressures are in the middle section, and the maximum change rate of aerodynamic pressure occurs at the entrance area. After the train exits the housing for sound emission alleviation, the pressure amplitude at the central region is always higher than those close to the entrance/exit. The dominant frequency of the aerodynamic pressure is identified and explained using wave propagation theory, the decay rate of the aerodynamic pressure at all sections is close.

Effect of Simple Fans on the Positive Pressure and Air Change Rate in Container Construction

Effect of Simple Fans on the Positive Pressure and Air Change Rate in Container Construction

INVESTIGATION OF PULSE VIBRATION OF THE PERIODICALLY WORKING INJECTOR OF THE MILKING WASHING SYSTEM

As a result of the analysis of technical and technological support of washing of milking installations it is established that the most effective are circulating systems of washing with regulated formation of a stopper mode with use of air injectors on the basis of automatic control. The consequences of periodic operation of the injector is the phenomenon of hydraulic shock, which is caused by a sudden change in the phase distribution of the flow of two-phase washing solution. This leads to a sudden change in the momentum of the two-phase washing solution, causing a pressure wave moving through the system. This pressure wave can lead to the destruction of milk deposits on the walls of the milk line, as well as to possible damage to the equipment of the milk system. The aim of the study is to increase the efficiency of the milking system flushing system by using pulsed vibration of a periodically operating injector. As a result of numerical simulation of the process of washing the milk line of the milking parlor using an injector in the software package STAR-CCM + was determined by the dynamics of changes in vacuum pressure at a distance from the injector (p (0 m), p (1 m), p (2 m), p ( 3 m), p (4 m), p (5 m)) and the dynamics of changes in the content of components of the multiphase medium (washing solution αf, air αg, milk αm) for four options: the injector is constantly closed, the injector is constantly open and the injector is periodically opened (1 s and 9 s) and closes (1 s and 9 s). It is established that the use of a periodic injector allows to reduce the milk content in the milk line faster and by a larger value, which indicates a better washing process. The addition of the physical-mathematical apparatus of the hydraulic shock phenomenon for a periodically operating air injector of the flushing system allowed to establish that the rate of pressure change depends on the velocities and concentrations of phases of two-phase washing solution, ie its flow regime and shock wave propagation velocity. Therefore, the rate of pressure change Δp / Δt is chosen as a criterion for the action of hydraulic shock.

Progress report on addressing meteotsunami risk in the eastern Yellow Sea

On 31 March 2007, strong, tsunami-like waves of 1.0–2.5 m were recorded at most tide gauges along the west coast of Korea. The following year, on May 4, unexpected, abnormal waves in the eastern Yellow Sea reached a maximum height of ∼1.3 m. Both events occurred without warning, resulting in severe loss of life and property. Subsequent analysis found that these tsunami-like waves were meteotsunamis generated by air pressure oscillations. Evidence of possible meteotsunamis has been recorded by existing observation systems. However, the lack of understanding of the phenomenon and meteotsunami-specific monitoring system has hindered community preparedness, resulting in severe damage. We utilized existing observation systems (meteorological stations, tide gauges, and radar) during 2018 to develop a real-time meteotsunami monitoring system in the eastern Yellow Sea. This system detects the intensity and propagation of air pressure oscillations to identify potential coastal hazards and prevent damage caused by meteotsunamis. Two air pressure disturbance methods for measuring intensity of air pressure oscillation (a range of pressure changes over a 60 min window vs the rate of pressure change over a 10 min window) were compared, and several test operations were performed during development of the proposed system. The progress and limitations of the current observation and monitoring system were confirmed based on recent monitoring reports of air pressure jumps during the meteotsunamis on 7 April 2019. To address the insufficient lead time of meteotsunami warnings, installation and testing of open-ocean buoys outfitted with pressure sensors commenced in 2019.

Experiment and simulation of JP-5 vapor/air mixture deflagration in enclosed space

To evaluate the deflagration risk of a premixed gas containing air and high-flash-point JP-5 jet fuel vapor, deflagration experiments were conducted in 1-m³ and 8-m³ closed vessels. The variations in deflagration pressure, flame propagation velocity, temperature, and other parameters under different concentrations and vessel volumes were studied. A large eddy simulation with a premixed gas combustion model was performed, and the obtained results were validated based on full-scale experimental data. The influence of the baffle-blocking ratio on the deflagration hazard was studied. The experimental results highlight the variation trend and numerical range of the deflagration pressure and flame propagation velocity of JP-5 vapor/air mixtures in a closed vessel. An increase in the deflagration vessel volume only extended the pressure rise time and reduced the rate of pressure change. The numerical simulation results supplemented and explained the experimental flame propagation and pressure variation and provided a more realistic deflagration temperature. The baffles in the closed vessel increased the flame turbulence and the rate of pressure rise and enhanced the deflagration hazard.

Analytical model for predicting residual stresses in abrasive waterjet peening

Abrasive waterjet peening (AWJP) is a new mechanical surface treatment where particles are delivered by a waterjet to induce plastic deformation and achieve surface strengthening effects on a workpiece. Although fatigue strength can be improved by inducing compressive residual stress, the prediction of residual stress distribution remains challenging because particle–workpiece interaction occurs with randomicity, superposition, and overlapping. In this paper, a theoretical model is proposed for predicting workpiece plastic deformation and compressive residual stress by analysing i) the non-uniform energy distribution of the AWJP beam caused by the non-uniformity of the abrasive size, spatial distribution, and impact velocity; ii) material hardening among multiple impacts by abrasive particles; and iii) overlapping traces induced by the changing position of the AWJP beam. The AWJP experiments were conducted in single-pass/multiple-pass/multiple-overlapping footprints with different pump pressures, traverse speeds, and jet centre distances of the adjacent traces to validate the model. The results showed good agreement with the predicted surface roughness and compressive residual stress. Compressive residual stress increased with the pump pressure, whereas the effect of pump pressure change rate decreased when the pump pressure was increased; further, residual stress is nearly constant with the variation in traverse speed and jet centre distance of the adjacent traces when it decreases to a certain value. These results can act as references for the control of residual stress and the prediction model can aid industrial manufacturing in AWJP parameter optimisation (e.g. pump pressure, traverse speed, surface roughness, compressive residual stress, and centre distance between two adjacent traces).

Evolution of the Micropore Structure of Ammonium Perchlorate during Low-Temperature Decomposition and Its Combustion Characteristics

Ammonium perchlorate (AP) is a common oxidant in solid propellants, and its thermal decomposition characteristics at low temperatures (less than 240 °C) are key to the study of the thermal safety of propellants. Here, the low-temperature thermal decomposition characteristics of AP were investigated at 230 °C. The micromorphology of the low-temperature decomposition residues was characterized by scanning electron microscopy and 3D nano-computed tomography in order to analyse the evolution of microscopic pore structures, and the effect of the AP pore structure on combustion performance was then tested and analysed with a homemade closed bomb. The results demonstrate that the low-temperature decomposition of AP first occurs near the surface of the particles, simultaneously starting at multiple points and forming pores, and then gradually expands towards the interior until almost all of the pores connect with one other. Compared with ordinary AP, porous AP has a significantly improved combustion rate. When the ratio of porous AP to Al was 80:20, the peak pressure in the closed bomb was increased by 2.7 times; the rate of change in peak pressure increased 34 times, leading to a higher reaction speed and higher reaction intensity, and a typical explosion reaction occurred.

Ophiopogon japonicas (Linn. f.) Ker-Gawl. extract ameliorates chronic heart failure in rats

Purpose: To investigate the effect of Ophiopogon japonicas (Linn. f.) Ker-Gawl. extract (OJKE) on oxidative stress and hemodynamics in chronic congestive heart failure (CHF) rats.
 Methods: The rats were modelled to congestive heart failure (except normal group) , and then randomly divided into normal control group, model (untreated) group, captopril group, high-dose, middle-dose and low-dose of OJKE groups. They were treated for 4 weeks as appropriate for each group. At the end of treatment, the hemodynamic function, whole heart weight index, and blood creatinine kinase (CK), as well as superoxide dismutase (SOD), malondialdehyde (MDA), nitric oxide (NO), nitricoxide synthase (NOS) were determined.
 Results: Compared with the normal control group, arterial systolic pressure (SBP), diastolic pressure (DBP), mean arterial pressure (MAP), heart rate (HR), left ventricular systolic peak (LVSP), and left ventricular pressure change rate (dp/dt max) significantly decreased (p < 0.05), while left ventricular end diastolic pressure (LVEDP), whole heart weight index, blood CK, MDA, NO, NOS significantly increased in the untreated group (p < 0.05). A high dose of OJKE significantly improved hemodynamic function, lowered MDA (8.33 ± 2.12 nmol/mL) and NO (20.58 ± 3.53 umol/L) levels (p < 0.05), and also decreased CK (0.53±0.37 U/mL) and NOS (22.46±3.29 U/mL) in CHF rats (p < 0.05).
 Conclusion: OJKE improved adriamycin-induced chronic congestive heart failure in rats significantly.

Thermal Condition and Air Quality Investigation in Commercial Airliner Cabins

Cabin air quality and thermal conditions have a direct impact on passenger and flight crew’s health and comfort. In this study, in-cabin thermal environment and particulate matter (PM) exposures were investigated in four China domestic flights. The mean and standard deviation of the in-cabin carbon dioxide (CO2) concentrations in two tested flights are 1440 ± 111 ppm. The measured maximum in-cabin carbon monoxide (CO) concentration is 1.2 ppm, which is under the US Occupational Safety and Health Administration (OSHA) permissible exposure limit of 10 ppm. The tested relative humidity ranges from 13.8% to 67.0% with an average of 31.7%. The cabin pressure change rates at the end of the climbing stages and the beginning of the descending stages are close to 10 hPa·min−1, which might induce the uncomfortable feeling of passengers and crew members. PM mass concentrations were measured on four flights. The results show that PM concentrations decreased after the aircraft cabin door closed and were affected by severe turbulences. The highest in-cabin PM concentrations were observed in the oldest aircraft with an age of 13.2 years, and the waiting phase in this aircraft generated the highest exposures.

Research on the Influence of Commercial Vehicle Electronic Control Pneumatic Braking Pressure Change Rate on Braking Ride Comfort

The paper evaluates the braking ride comfort of commercial vehicle through total weighted acceleration root mean square and Derivative of acceleration (Jerk). Based on the vehicle dynamics model, tire model and braking implement model, the commercial vehicle braking pressure, braking pressure change rate and braking ride comfort of correlation model is established. The commercial vehicle dynamics simulation model for braking pressure change rate is established by using MATLAB/Simulink software. The simulation comparison of MATLAB/Simulink and IPG/TruckMaker verify the correctness and effectiveness of the correlation model. Taking the effect of single and double braking chamber pressure change rate as an example. The effect of the unusual change of pressure change rate of the front and rear axle single braking chamber and the coaxial and ipsilateral braking chamber on the commercial vehicle braking ride comfort is analyzed by comparativing. Some theoretical basis for commercial vehicle in intelligent braking and automatic driving is provided.