Low-pressure Chamber Research Articles

Experimental study on spreading and burning characteristics of continuous spill fire under low pressure

To investigate the influence of low ambient pressure on spill fire, the methanol spill fire experiments on fireproof glass with discharge rates ranging from 60 to 180 mL/min were conducted in a low-pressure chamber. The spread radius, burning rate, and heat transfer process between liquid layer and glass of spill fire were analyzed in-depth under low ambient pressure of 60 kPa and atmospheric pressure of 101 kPa. The results showed the entire spread process of spill fire and found that the spreading radius under atmospheric pressure was slightly smaller than that under low-pressure environment. The burning rate of spill fire under atmospheric pressure is lower than low pressure which the relation between pressure and burning rate can be expressed as m⋅∝P0.32. With respect to the heat transfer process, the heat loss including radiation penetration and heat convection under 60 kPa was lower than under 101 kPa, and the heat convection loss was dominant under two pressures. Finally, a semi-theoretical model was developed to estimate the burning rate in the quasi-steady stage by considering the spreading radius and heat transfer process. The model was validated with the experimental data and showed reasonable accuracy.

Disrupted gut microbiota aggravates working memory dysfunction induced by high-altitude exposure in mice.

The widely accepted microbiome-gut-brain axis (MGBA) hypothesis may be essential for explaining the impact of high-altitude exposure on the human body, especially brain function. However, studies on this topic are limited, and the underlying mechanism remains unclear. Therefore, this study aimed to determine whether high-altitude-induced working memory dysfunction could be exacerbated with gut microbiota disruption. C57BL/6 mice were randomly divided into three groups: control, high-altitude exposed (HAE), and high-altitude exposed with antibiotic treatment (HAE-A). The HAE and HAE-A groups were exposed to a low-pressure oxygen chamber (60-65 kPa) simulating the altitude of 3,500-4,000 m for 14 days, The air pressure level for the control group was maintained at 94.5 kPa. Antibiotic water (mixed with 0.2 g/L of ciprofloxacin and 1 g/L of metronidazole) was provided to the HAE-A group. Based on the results of the novel object test and P300 in the oddball behavioral paradigm training test, working memory dysfunction was aggravated by antibiotic treatment. We determined the antioxidant capacity in the prefrontal cortex and found a significant negative influence (p < 0.05) of disturbed gut microbiota on the total antioxidant capacity (T-AOC) and malondialdehyde (MDA) content, as well as the activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px). The same trend was also observed in the apoptosis-related functional protein content and mRNA expression levels in the prefrontal cortex, especially the levels of bcl-2, Bax, and caspase-3. The high-altitude environment and antibiotic treatment substantially affected the richness and diversity of the colonic microbiota and reorganized the composition and structure of the microbial community. S24-7, Lachnospiraceae, and Lactobacillaceae were the three microbial taxa with the most pronounced differences under the stimulation by external factors in this study. In addition, correlation analysis between colonic microbiota and cognitive function in mice demonstrated that Helicobacteraceae may be closely related to behavioral results. Disrupted gut microbiota could aggravate working memory dysfunction induced by high-altitude exposure in mice, indicating the existence of a link between high-altitude exposure and MGBA.

Protective effects of salidroside on vascular endothelial cells in rats with frostbite after chronic hypoxia

Objective: To investigate the protective effects of salidroside on endothelial cells in rats with frostbite after chronic hypoxia. Methods: Healthy male SD rats, randomly divided into 3 groups with 10 rats in each group, which included the sham injury group, the model group, and the model +salidroside group. The rats in each group were placed in a composite low-pressure chamber to simulate a environment with a pressure of 54.1 kpa and a temperature of 23~25°C. The rats were exposed to hypoxia under these conditions for 14 days, during the experimental time the rats in the model+salidroside group were treated with 50 mg/kg salidroside daily. After the rats were removed from the low-pressure chamber, except for the sham injury group, frozen iron sheets were applied tightly to the back of the rats for 30 s, supplemented with low temperature for frostbite modeling. Blood and skin tissues were collected at 12 hours after modeling for testing. The structural changes in tissue and vascular endothelial cells were observed in the frostbite region. Vascular endothelial cell particulate EMP levels were detected. The levels of ICAM-1, sEPCR, vWF, ET-1 and NO secretion were determined. The expression levels of HIF-1α, p-PI3K, p-Akt and VEGF were detected by Western blot. Results: Salidroside could effectively reduce skin collapse in frostbitten areas. It could reduce the injury of frostbitten tissues, and improve the subcutaneous tissue necrosis and inflammatory cell infiltration. The autophagy of vascular endothelial cells was reduced. Compared with the model group (0.250±0.165)%, the expression of EMPs in the model+salidroside group (2.453±0.196)% was increased significantly (P＜0.01). In addition, the contents of NO (2.622±0.219)pg/ml was also significantly higher than that of the model group (1.616±0.152)pg/ml (P＜0.01), and the content of vWF (233.50±13.43)pg/ml was lower than that of the model group (315.60±8.78)pg/ml (P＜0.05). There was no significant difference in the levels of ICAM-1, sEPCR and ET-1. Salidroside significantly decreased the expressions of p-PI3K, p-Akt, VEGF and HIF-1α protein in vascular endothelial cells of rats with frostbite (P＜0.01). Conclusion: Salidroside can reduce endothelial cell damage, reduce endothelial cell autophagy and promote endothelial cell regeneration. Based on the PI3K/Akt pathway, salidroside has a good protective effect on endothelial cells of rats with frostbite after chronic hypoxia.

Double Chambered Right Ventricle with Small Ventricular Septal Defect: Detection and Evaluation by Color Doppler Echocardiography - A Rare Case Report

Double-chambered right ventricle (DCRV) is a rare condition seen only in 0.5-2.0 % of all cases of congenital heart disease (CHD). 80-90 % of DCRV cases are associated with various other congenital heart defects. In particular, perimembranous large ventricular septal defect (VSD) is the most common anomaly associated with DCRV. Anomalous muscular bundle (AMB) typically divides the right ventricle (RV) into a proximal high pressure and distal low pressure chamber. This aberration is often diagnosed during childhood and adolescence. Here we are presenting an exceedingly rare case of asymptomatic DCRV in an adolescent female with a small perimembranous VSD. Keywords: Double Chambered Right Ventricle, small perimembranous VSD, DCRV in an adolescent, facial anomalies, cleft upper lip

Lactobacillus johnsonii YH1136 plays a protective role against endogenous pathogenic bacteria induced intestinal dysfunction by reconstructing gut microbiota in mice exposed at high altitude.

BackgroundIntestinal microbiota plays an important role in maintaining the microecological balance of the gastrointestinal tract in various animals. Disturbances in the intestinal microbiota may lead to the proliferation of potentially pathogenic bacteria that become the dominant species, leading to intestinal immune disorders, intestinal inflammation, and other intestinal diseases. Numerous studies have been confirmed that high-altitude exposure affects the normal function of the intestine and the composition of the intestinal microbiota. However, it is still necessary to reveal the changes in intestinal microbiota in high-altitude exposure environments, and clarify the relationship between the proliferation of potentially pathogenic bacteria and intestinal injury in this environment. In addition, explored probiotics that may have preventive effects against intestinal diseases.Methods and resultsC57BL/6 mice were randomly divided into three groups, a high-altitude group (HA), control group (C), and high-altitude probiotic group (HAP). The HA and HAP groups were subjected to hypoxia modeling for 14 days in a low-pressure oxygen chamber with daily gavage of 0.2 mL of normal saline (HA) and Lactobacillus johnsonii YH1136 bacterial fluid (HAP), while the control group was fed normally. L. johnsonii YH1136 was isolated from feces of a healthy Tibetan girl in Baingoin county, the Nagqu region of the Tibet Autonomous Region, at an altitude of 5000 meters. Our observations revealed that gavage of YH1136 was effective in improving the damage to the intestinal barrier caused by high-altitude exposure to hypoxic environments and helped to reduce the likelihood of pathogenic bacteria infection through the intestinal barrier. It also positively regulates the intestinal microbiota to the extent of Lactobacillus being the dominant microbiome and reducing the number of pathogenic bacteria. By analyzing the expression profile of ileal microRNAs and correlation analysis with intestinal microbiota, we found that Staphylococcus and Corynebacterium1 cooperated with miR-196a-1-3p and miR-3060-3p, respectively, to play a regulatory role in the process of high-altitude hypoxia-induced intestinal injury.ConclusionThese findings revealed the beneficial effect of L. johnsonii YH1136 in preventing potential endogenous pathogenic bacteria-induced intestinal dysfunction in high-altitude environments. The mechanism may be related to the regulation of intestinal injury from the perspective of the gut microbiota as well as miRNAs.

Influence of Aviation Conditions on Lithium-Ion Batteries

Stopping climate change and global temperature rise needs a determined course of action in several technology fields and the development of ZERO-CO2 aircrafts and low emission battery-ICE aircrafts, as well. Batteries in hybrid-electric or fully-electric aircrafts are an option to decrease emissions. The battery requirements for the aviation sector regarding specific energy, energy density and safety are high. Lithium-ion batteries are today the only commercially available technology to meet these requirements, but adequate technology readiness is only proven for the automobile sector while TRL levels 8 and 9 for implementation readiness of batteries in the aviation sector is still ongoing. A crucial aspect for aviation applications is the operation behavior in high altitude including low temperature, wide humidity ranges and especially low pressure. There is little published information available on the effects of low pressure on battery performance. Therefore, different commercially available lithium-ion batteries were tested from atmospheric pressure down to 250 hPa, which corresponds to a flight altitude up to 10,000 m, according to the International Standard Atmosphere (ISA). Since NMC and NCA cathode materials are promising for aviation due to their high specific energy, and LFP cells are promising because of their high safety, the following batteries were selected: 20 Ah HP602030 LFP cylindrical cell (EAS Batteries GmbH, GER). 10 Ah HE 341440 NCA cylindrical cell (EAS Batteries GmbH, GER). 12 Ah SLPB065070180 NMC pouch cell (Kokam Co. Ltd., KOR) To examine the influence of pressure on the battery behavior, constant current discharge tests at 1C 0.5C and 2C rates as well as impedance measurements in 10% SOC steps were performed in a climate controlled low-pressure chamber. The batteries were operated under different temperatures and in controlled low pressure. The pressure was first set to atmospheric pressure as a reference and then lowered to 750 hPa, 500 hPa and 250 hPa. To further examine altitude influences, current cycles and impedance spectroscopy were performed at different temperature and humidity values.The behavior of the cylindrical cells showed hardly any pressure dependency, while the examined pouch cell’s behavior did show a pressure dependency.All batteries showed strong temperature dependency but hardly any humidity dependency.In this presentation the influence of pressure, temperature and humidity on voltage, capacity, resistance and impedance of the afore mentioned batteries will be discussed. The batteries are compared regarding their aviation applicability with special respect to low pressure. The parameters for each environmental condition can then be used to parameterize a battery model suitable for aviation applications.

Enhancement of Magnetic and Dielectric Properties of Ni0.25Cu0.25Zn0.50Fe2O4 Magnetic Nanoparticles through Non-Thermal Microwave Plasma Treatment for High-Frequency and Energy Storage Applications.

Spinel ferrites are widely investigated for their widespread applications in high-frequency and energy storage devices. This work focuses on enhancing the magnetic and dielectric properties of Ni0.25Cu0.25Zn0.50 ferrite series through non-thermal microwave plasma exposure under low-pressure conditions. A series of Ni0.25Cu0.25Zn0.50 ferrites was produced using a facile sol–gel auto-ignition approach. The post-synthesis plasma treatment was given in a low-pressure chamber by sustaining oxygen plasma with a microwave source. The structural formation of control and plasma-modified ferrites was investigated through X-ray diffraction analysis, which confirmed the formation of the fcc cubical structure of all samples. The plasma treatment did not affect crystallize size but significantly altered the surface porosity. The surface porosity increased after plasma treatment and average crystallite size was measured as about ~49.13 nm. Morphological studies confirmed changes in surface morphology and reduction in particle size on plasma exposure. The saturation magnetization of plasma-exposed ferrites was roughly 65% higher than the control. The saturation magnetization, remnant magnetization, and coercivity of plasma-exposed ferrites were calculated as 74.46 emu/g, 26.35 emu/g, and 1040 Oe, respectively. Dielectric characteristics revealed a better response of plasma-exposed ferrites to electromagnetic waves than control. These findings suggest that the plasma-exposed ferrites are good candidates for constructing high-frequency devices.

Study on statistical invariance of probability processing and fluctuation characteristics of consecutive images of horizontal spray flame under low-pressure

With the development of the plateau environment, to make better use of the heat energy and safety of combustion devices, the structure and stability evaluation of horizontal jet flame and other related issues have attracted more and more people's attention. Consecutive image processing of flame is one of the emerging methods to evaluate the flame structure. In this paper, the statistical invariance of horizontal spray flame under low pressure is investigated experimentally and photographically, especially the characteristic of flame terminal fluctuation. A consecutive flame image of 0.05 MPa atmospheric pressure taken by conventional 25 frames per second in a low-pressure chamber was processed with probabilistic statistics, and the probability statistical contours were obtained by binarization statistics for the consecutive 100 to 1000 frames. The results show that different flame characteristic parameters have a different minimum statistical threshold, but most of them are between 300 and 400. The most reasonable statistical interval is determined by combining it with the flame stability evaluation index. The variation mechanism and feasibility of using statistical invariance to characterize flame stability are illustrated from the viewpoint of flame fluctuation characteristics. This is of great significance to the integrity of probabilistic processing of horizontal jet flame and lays a theoretical foundation for flame stability evaluation.

Study on injury parameters of severe blast injury in mice at plain and plateau based on equivalent trauma

To explore the establishment of the interconvertible injury parameters of same severe blast injury in mice at plain and plateau. A total of 157 C57BL/6 male mice were randomly divided into plain control group (8 mice), plain injury group (77 mice), plateau control group (8 mice) and plateau injury group (64 mice) according to random number table method. The mice in plateau control group and plateau blast injury group had been placed in animal experimental low-pressure oxygen chamber to simulate 4 000 meters plateau environment for 5 days in advance. Then the mice in plain blast injury group and plateau blast injury group were put into biological shock tube, respectively. Different pressures of the driving section were selected to establish the severe blast injury models in mice at plain and 4 000 meters plateau to reach approximately 70% mortality within 72 hours. The equivalent traumatic condition at 24 hours after blast injury in different groups was verified by the series of experiments including gross autopsy, lung wet/dry weight ratio (W/D), hematoxylin-eosin (HE) staining and histological scoring. The mice mortality were basically consistent between the plain injury group (65%) and plateau injury group (75%) when 5.4 MPa and 4.0 MPa of the driving section pressures were chosen, respectively. Compared with the corresponding control groups, the lungs showed massive hemorrhage (patchy and diffuse) with significant pulmonary edema in both plain 5.4 MPa-injured group and the plateau 4.0 MPa-injured group at 24 hours after blast injury. Compared with the plateau control group, the pulmonary W/D ratio were significantly increased in the plateau injury group (5.579±0.646 vs. 4.476±0.076, P < 0.05), while the difference between plateau injury group and the plain control group was not statistically significant (5.303±1.020 vs. 4.015±0.144, P > 0.05). Also, compared with the corresponding control groups, the analysis of lung histopathological sections showed that there were several pathological changes including large alveolar rupture and fusion, thickened alveolar walls, and a small amount of inflammatory cell infiltration in the alveolar lumen in the groups of plain 5.4 MPa and plateau 4.0 MPa. In addition, the histopathological scores of lung in the groups of plain 5.4 MPa and plateau 4.0 MPa were significantly higher than that in corresponding control group (8.67±0.82 vs. 1.67±0.52, 9.00±1.10 vs. 2.17±0.41, both P < 0.05), however, there was no statistical difference for the above score between plain blast injury group and plateau blast injury group. The pressures of driving section 5.4 MPa and 4.0 MPa are injury parameters to establish equivalent severe blast injury in mice at plain and plateau, respectively, which can be converted to each other. This study provides support for the application and evaluation of prevention and treatment technology for severe blast injury in special environment.

Increased self-reported sensitivity to environmental stimuli and its effects on perception of air quality and well-being.

In previous studies, negative associations were found between increased environmental sensitivity and general well-being as well as positive perception of air quality. However, only a few studies with partly inconsistent results examined this relation under exposure. They tried to determine whether people with increased environmental sensitivity react to real environmental conditions with changes in current well-being and perception of air quality. Pooled data from two single-blinded randomized controlled trials with different exposure levels were analyzed. Participants were exposed to different levels of volatile organic compounds (VOC) and carbon dioxide (CO₂) in the front part of a former in-service wide-body airplane inserted in a low-pressure chamber. Three exposure groups were created depending on the VOC/CO₂ levels: low, medium and high. Subjects repeatedly answered questions about their current mental well-being and about perception of air quality and odor intensity. Based on self-reported data the participants were classified into groups with low and higher environmental sensitivity. Data were evaluated using a 2 (environmental sensitivity) x 3 (exposure) ANCOVA with repeated measures. 503 individuals (221 females) participated (mean age: 42.8±14.5 years). Thereof, 166 individuals were assigned to the group with higher environmental sensitivity; they reported poorer psychological well-being regarding vitality (F (1,466)=16.42, p&lt;.001***, partial η²=0.034) and vigilance (F (1,467)=7.82, p=.005**, partial η²=0.016) and rated the pleasantness of air quality (F (1,476)=7.55, p=.006**, partial η²=0.016) and air movement (F (1,474)=5.11, p=.024*, partial η²=0.011) worse than people in the low sensitivity group. Exposure levels showed no effects. No systematic differences between men and women were found. Increased environmental sensitivity shared common variance with negative affectivity, another person-related variable. Its explanatory power was higher for evaluations of the environment whereas no differences between the concepts in explaining current psychological well-being were found. Even a slightly elevated level of environmental sensitivity led to worse ratings of the environment with no clear relation to the real environment. Consequently, environmental sensitivity should be considered as a confounding factor in environmental exposure studies. The independency from real exposure levels is in line with the results from previous studies showing that the differences in environmental ratings are probably also driven by psychological factors.

Revisiting Folger's pouch in double-chambered right ventricle.

Folger's pouch is a right ventricular outflow pouch arising from the distal low-pressure chamber in double-chambered right ventricle. It is rarely described on echocardiogram due to difficult visualization and lack of knowledge of its existence. Retrospective assessment of echocardiogram after an angiocardiographic evaluation demonstrates the pouch in a modified high parasternal view.

Using CMOS Image Sensors to Determine the Intensity of Electrical Discharges for Aircraft Applications

The development of more electric aircrafts (MEA) and all electric aircrafts (AEA) inevitably implies an increase in electric power and a consequent increase in distribution voltage levels. Increased operating voltages coupled with low pressure in some areas of the aircraft greatly increase the chances of premature insulation failure. Insulation failure manifests itself as surface discharges, arc tracking, arcing, and disruptive or breakdown discharges, in order of increasing severity. Unfortunately, on-board electrical protections cannot detect discharges at an early stage, so other strategies must be explored. In their early stage, insulation faults manifest as surface and corona discharges. They generate optical radiation, mainly in the near-ultraviolet (UV) and visible spectral regions. This paper focuses on a method to detect the discharges, locate the discharge sites, and determine their intensity to facilitate predictive maintenance tasks. It is shown that by using small size and low-cost image sensors, it is possible to detect, locate, and quantify the intensity of the discharges. This paper also proposes and evaluates the behavior of a discharge severity indicator, which is based on determining the intensity of digital images of the discharges, so it can be useful to apply predictive maintenance tasks. The behavior and accuracy of this indicator has been tested in the laboratory using a low-pressure chamber operating in the pressure range of 10–100 kPa, which is characteristic of aircraft applications, analyzing a needle-plane air gap geometry and using an image sensor. The proposed method can be extended to other applications where electrical discharges are an issue.

Effect of pressure and stacking method on combustion characteristics of paper stacks

The experimental study on the combustion characteristics of paper stack fires was carried out in a low-pressure chamber. The variability of which with different environmental pressures and stacking methods were investigated. The mass of each group of experimental paper strips was 107 g. Three iron frames had the same volume, but different lengths and widths, and the strips were placed evenly in the frames to simulate different ways of paper stacking. The combustion tests of the paper stack were conducted at four ambient pressures of 101 kPa, 80 kPa, 60 kPa, and 40 kPa, respectively. The parameters measured during the experiments included mass loss, heat release rate (HRR), and flame temperature. The experimental results showed that the stacking type and pressure significantly affected the properties of the paper stack fire. For instance, the burning rate was influenced by the cross-sectional combustion area, pressure, and load height. There was a linear relationship between the ratio of the peak burning rate to the characteristic length of the bottom surface and the pressure-load height. The intensity factor of the paper stack fire was closely related to the environmental pressure: the paper stack fire under atmospheric pressure was generally a fast-growing one, which was a medium-growing fire under about 80 kPa. In comparison, that was a slow-growing fire when the pressure was 60 kPa.

Charged-particles measurements in low-pressure iodine plasmas used for electric propulsion

This paper investigates iodine as an alternative propellant for space plasma propulsion. Measurements are taken in a low-pressure inductively-coupled plasma chamber used as the ionization stage of a gridded ion-engine. Langmuir probes are used to measure the electron density and the electron energy distribution functions spatial variations between the inductive coil and the extraction grids for several radio-frequency (RF) powers and mass flow rates. Measurements in iodine are compared to xenon, krypton and argon in order to evaluate performances of these various propellants for ionization (and therefore power) efficiency. At low mass flow rates, iodine is found to be the most efficient propellant, however, as the mass flow rate increases, the ionization cost in iodine increases rapidly due to both its molecular and electronegative nature. The ratio of negative ion to electron density is measured using laser-induced photodetachment in order to quantify the effect of iodine electronegativity. Finally, all measurements are compared to a previously published global (volume-averaged) model. The agreement between model and experiments is acceptable, however several modelling improvements are proposed.

Comparison of distribution of verbascoside in normoxic and hypoxic rats

This study established a high performance liquid chromatography(HPLC) method for the simultaneous determination of verbascoside(VB) and its main metabolite caffeic acid(CA) in rat tissue samples. A low-pressure low-oxygen animal experimental chamber was used to simulate the plateau environment for establishing the hypoxic rat model. After intragastric administration of 300 mg·kg~(-1) VB, the normoxic and hypoxic rats were sacrificed for the collection of heart, liver, spleen, lung, kidney, brain, muscle, large intestine, small intestine, and stomach tissue samples at the time points of 30, 60, and 90 min. VB and CA concentrations in each tissue sample were measured by HPLC, and the distribution of VB and CA in normoxic and hypoxic rats was compared. The results showed that after intragastric administration, VB can be rapidly absorbed and distributed into various tissues including brain in both normoxic and hypoxic rats, indicating that VB can pass through the blood-brain barrier. In the gastrointestinal tract, VB was mainly distributed in small intestine, which suggested that the main absorption site of VB was small intestine. A large amount of VB was detected in muscle and lung, and only a small amount in other tissues. CA was detected in other tissues except brain, heart, and muscle. Small intestine had the most abundant CA, followed by stomach, large intestine, and kidney, and only a small amount of CA was detected in the liver, spleen, and lung(&lt;50 ng·mL~(-1)). The results indicated that VB may be mainly absorbed and metabolized in the gastrointestinal tract to produce CA and was possibly excreted through kidney. Compared with normoxic rats, hypoxic rats had reduced and slow distribution of VB and increased ratio of VB concentration in tissue to plasma, which implied that the relative proportion of VB from systemic circulation to tissues was increased in hypoxic rats. This study provides a basis for the application of VB in anti-hypoxia therapy and for the formulation of anti-hypoxia dosing regimens.

Thermal runaway propagation in linear battery module under low atmospheric pressure

Understanding the mechanism of battery thermal runaway propagation under low atmospheric pressure is critical for the safe operation of battery energy storage systems. This work explores the thermal runaway propagation over a linear arrayed 18650-type lithium-ion battery module in a low-pressure chamber. The effects of ambient pressure (0.1 kPa to 100 kPa), temperature, and electrical connection mode are comprehensively investigated. Results indicate that the propensity of thermal runaway propagation for the open-circuit battery array is much lower, and it only occurs at high ambient temperature and ambient pressure. For parallel-connected battery modules, as ambient pressure decreases, the rate of thermal-runaway propagation first increases due to the reduced environmental cooling (i.e., thermal controlled). It then falls due to lower remaining electrolytes after venting (i.e., venting controlled). The pressure of maximum thermal runaway propagation speed is 60 kPa. The maximum time interval for the thermal runaway of the next cell is about 7 min. A simplified heat transfer analysis was proposed to explain the trend and limits of thermal runaway propagation and reveal the dual effect of pressure. This work provides new insights into thermal runaway propagation, which can deepen the understanding of battery fire safety under low pressure and inspire the thermal-safety design of the lithium-ion battery modules.

Effect of High-altitude Hypoxia Environment on Uric Acid Excretion, Desmin Protein Level in Podocytes, and Na+-K+- ATPase Activity.

To investigate the oxidative stress and adaptive compensation of kidneys in rats in high-altitude hypoxia environments, 20 Wistar rats (3 months) were randomly and equally grouped. The rats in the test group were fed in a low-pressure oxygen chamber, and those in the control group (controls) were fed in a normal environment. On the 5th, 10th, 20th, and 30th day, the excretion of uric acid in rats was detected by a biochemical analyzer, the level of desmin protein in rat podocytes was detected by immunohistochemistry, and the activity of Na+-K+- ATPase in rat proximal tubular epithelial cells was measured by liquid scintillation method. The results showed that with the increased time, the level of uric acid in the blood of rats in the test group increased dramatically (P<0.05). On the 30th day, the blood uric acid content of the test group was 52.33μmol/L, and that of the control group was 38.43μmol/L. The blood uric acid content in the test group was dramatically increased relative to the control group. Immunohistochemistry showed that the desmin protein in podocytes of the test group (0.14) was considerably higher than that in the control group (P<0.05). The Na+-K+- ATPase activity of proximal renal tubular epithelial cells in the test group was 611.2 pmol pi/mg protein/h, which was considerably lower than the versus control group (P<0.05). In summary, in high altitude hypoxia environment, uric acid accumulated in the body, and renal filtration and excretion ability was limited.

Chamber with Inverted Electrode Geometry for Measuring and Control of Ion Flux-Energy Distribution Functions

Measurements of ion flux-energy distribution functions at the high sheath potential of the driven electrode in a classical low-pressure asymmetric capacitively coupled plasma are technically difficult as the diagnostic device needs to float with the applied radio frequency voltage. Otherwise, the ion sampling is disturbed by the varying electric field between the grounded device and the driven electrode. To circumvent such distortions, a low-pressure plasma chamber with inverted electrode geometry, where the larger electrode is driven and the smaller electrode is grounded, has been constructed and characterized. Measurements of the ion flux-energy distribution functions with an energy-selective mass spectrometer at the high sheath potential of the grounded electrode are presented for a variety of conditions and ions. The potential for suppressing low-energy ions from resonant charge transfer collisions in the sheath by the dilution of the working gas is demonstrated. Additionally, the setup is supplemented by an inductively coupled plasma that controls the plasma density and consequently the ion flux to the substrate while the radio frequency bias controls the ion energy. At high ion energies, metal ions are detected as a consequence of the ionization of sputtered electrode material. The proposed setup opens a way to study precisely the effects of ion treatment for a variety of substrates such as catalysts, polymers, or thin films.

Visualization of Pressure and Skin-Friction Fields on Rotating Blade Under Low-Pressure Conditions

Distributions of the pressure and mass transfer coefficient on rotating blades under low-pressure (low-Reynolds-number) conditions were visualized, whereas the latter is closely related to the skin-friction distribution. Two types of optical measurement techniques, lifetime-based pressure-sensitive paint (PSP) measurements and sublimation visualization, were implemented for the experiment inside a low-pressure chamber. For the lifetime-based PSP measurement, different types of PSP were compared, and the one most suitable in low-pressure applications was selected. In addition, the gate time setting for the low-pressure condition was determined. For the sublimation method, naphthalene was selected as the sublimation surface based on previous studies. The rotating blade test model was a 0.3-m-diam rotor system with two rectangular blades with an aspect ratio of two. The experiments were carried out at a rotational speed of 2400 rpm and at an ambient pressure of 10 kPa. The three-fourth-span Reynolds number was 9000. The pitch angle of the blades was set to 0–20 deg. Both methods successfully illustrated clear images of the distribution of pressure and mass transfer coefficients on the upper surface of the blade, and the measurement in the low-pressure environment was successful.

P167 ECG ABNORMALITIES AND DOUBLE CORONARY FISTULA

Abstract Coronary artery fistula (CAF) is defined as anomalous communication between coronary arteries and cardiac chamber or a major thoracic vessel. CAF are a rare coronary anomaly, mostly congenital, first described by Krause in 1856. In literature the incidence in general population is approximately 0,002%. Detection of CAF during coronary angiography is usually accidental. In 50% of cases CAF originate from right coronary artery, in 30% they originate from LAD, while in the rest of the percentage CAF originate from left circumflex artery. CAF drain into low–pressure chamber (right ventricle or right atrium, superior Vena Cava or pulmonary artery). We can distinguish CAF into little or medium sized, usually with silent clinical course, and large sized CAF, with variable clinical signs, depending on the extent of the shunt and on the hemodynamic overload of the receiving chamber. We describe the case of a 57 y.o woman with hypertension, admitted for femur fracture. ECG showed bifasic T waves in the anterior leads, already described in a previous ECG. Normal systolic function and no valvular defect were found on the echocardiogram. Patient was asymptomatic. Coronary angiography documented normal coronary arteries, with a double coronary fistula: the first from a septal branch of posterior descending and the second one from distal branches of the first diagonal. Even if CAF have often a favorable clinical course with no relevant consequences for the patient, it’s crucial to obtain more information about their functional implication and their anatomic connections. Indeed, rare cases of sudden cardiac death have been described in patients with CAF involved in myocardial ischemia based on the theft syndrome mechanism. Echocardiographic evaluation of the patient to detect associated congenital abnormalities, pressure overload of the receiving chambers and the extent of the shunt on the coronary angiography are crucial for the proper management of CAF. In the case described above we decided to optimize therapy adding beta–blocker (to reduce the overload caused by the two coronary fistula).