Low Atmospheric Pressure Research Articles

Extreme weather conditions influence the frequency of epistaxis-related emergency room visits.

Climate change has been associated with an increase in extreme weather conditions. The aim of this study was to identify environmental factors and the effect of extreme weather events (95th percentile) on the risk for epistaxis-related emergency room visits (EV). A total of 2179 epistaxis-related EVs were identified between 2015 and 2018. A distributed lag non-linear model was fitted to investigate the relationship between extreme weather conditions and the total number of epistaxis-related EVs per day. Cumulative relative risk (cRR) is defined as the cumulated daily risk of EV for epistaxis within a stated period after an extreme weather condition compared to the risk of EV at the median value of that weather condition. At a mean daily temperature of 27°C (P95), cRR for epistaxis-related EV was 2.00. At a relative humidity of 39% (P5), cRR was highest on day 3 at 1.59, while extremely high humidity (92%, P99) led to a decreased cRR of 0.7 on day 1. Intense precipitation of 24mm (P99) reduced the cRR on day 3 to 0.38. For prolonged extreme conditions over three days, extremely low wind speed, as well as both high and low atmospheric pressure events, diminished cRR. Extreme temperatures, relative humidity, and precipitation, as well as extended periods of extreme wind speeds and atmospheric pressure, significantly impact cRR for epistaxis-related EVs.

Effect of air-entraining agents combined with superabsorbent polymers on pore structure and frost resistance of mortar prepared under low air pressure

Superabsorbent polymers (SAPs) combined with air-entraining agents (AEAs) were used to improve the frost resistance of mortar pepared under low air pressure in this study. Effects of SAPs combined with AEAs on the pore structure and frost resistance of mortar were investigated. Results showed that the combined use of SAPs and AEAs could improve the frost resistance of mortar made under low air pressure efficiently. This is further clarified by the changes of the pore structure. SAPs had a better performance in air-entraining as well as internal curing under low air pressure than those under a normal atmosphere. In addition, SAPs combined with AEAs could greatly optimize the pore structure of mortar prepared at low air pressure, especially reduce the number of pores larger than 200 nm. Moreover, correlations between pore characteristic parameters and frost resistance were discussed based on the linear fitting method and grey correlation analysis method. Finally, a modified hydraulic pore pressure model considering the influence of air pressure was established, and calculation results showed that the hydraulic pore pressure during freezing decreased due to low air pressure.

The Synthesis and Characterisation of the High-Hardness Magnetic Material Mn2N0.86.

High-quality P6322 Mn2N0.86 samples were synthesised using a high-pressure metathesis reaction, and the properties of the material were investigated. The measurements revealed that the Vickers hardness was 7.47 GPa, which is less than that predicted by commonly used theoretical models. At low air pressure, Mn2N0.86 and MnO coexist at 500 to 600 °C, and by excluding air, we succeeded in producing Mn4N by heating Mn2N0.86 in nitrogen atmosphere; we carefully studied this process with thermogravimetry and differential scanning calorimetry (TG-DSC). This gives a hint that to control temperature, air pressure and gas concentration might be an effective way to prepare fine Mn-N-O catalysis. Magnetic measurements indicated that ferromagnetism and antiferromagnetism coexist within Mn2N0.86 at room temperature and that these magnetic properties are induced by nitrogen vacancies. Ab intio simulation was used to probe the nature of the magnetism in greater detail. The research contributes to the available data and the understanding of Mn2N0.86 and suggests ways to control the formation of materials based on Mn2N0.86.

Use of δ18Oatm in dating a Tibetan ice core record of Holocene/Late Glacial climate

Ice cores from the northwestern Tibetan Plateau (NWTP) contain long records of regional climate variability, but refrozen meltwater and dust in these cores has hampered development of robust timescales. Here, we introduce an approach to dating the ice via the isotopic composition of atmospheric O2 in air bubbles (δ18Oatm), along with annual layer counting and radiocarbon dating. We provide a robust chronology for water isotope records (δ18Oice and d-excess) from three ice cores from the Guliya ice cap in the NWTP. The measurement of δ18Oatm, although common in polar ice core timescales, has rarely been used on ice cores from low-latitude, high-altitude glaciers due to (1) low air pressure, (2) the common presence of refrozen melt that adds dissolved gases and reduces the amount of air available for analysis, and (3) the respiratory consumption of molecular oxygen (O2) by micro-organisms in the ice, which fractionates the δ18O of O2 from the atmospheric value. Here, we make corrections for melt and respiration to address these complications. The resulting records of water isotopes from the Guliya ice cores reveal climatic variations over the last 15,000 y, the timings of which correspond to those observed in independently dated lake and speleothem records and confirm that the Guliya ice cap existed before the Holocene. The millennial-scale drivers of δ18Oice are complex and temporally variable; however, Guliya δ18Oice values since the mid-20th century are the highest since the beginning of the Holocene and have increased with regional air temperature.

Drying characteristics of concrete under surface low air pressure

The humidity change of C30, C50, and C80 concretes under surface low air pressure and atmospheric pressure were tested. Based on the mechanism of moisture transfer under low air pressure, a theoretical model of concrete humidity field considering the effect of pressure was established. The model was used to analyze the changes of concrete internal humidity field when the surface pressure changes. The results show that the relative humidity values of each concrete under low air pressure are lower than that of atmospheric pressure. And the effect is greater near the drying surface. The improved calculation model was used to calculate the humidity change of concrete under low air pressure. The calculated values were in good agreement with the experimental values. It can be used to study the internal humidity field of concrete under different pressure conditions.

Non-Thermal Plasma Technology for CO2 Conversion—An Overview of the Most Relevant Experimental Results and Kinetic Models

Global warming, along with increasing global energy demands, has led to the need for a sustainable and low-carbon-based energy economy. In addition to renewable energy technologies, such as biomass, solar, hydro, and wind, another possible strategy to mitigate climate change is the capture/conversion and recycling of CO2. In recent years, many methods for both CO2 capture (mainly adsorption, absorption, and membrane) and conversion (many electrolysis, catalyst, and plasma) have been investigated. Conversion technology is less studied but seems to be very promising. Within that, non-thermal plasma technology has received much interest because it works at low temperatures and atmospheric pressure, and there is no need for high temperature and high electricity consumption, which are typical of the catalyst and electrolysis conversion processes, respectively. Therefore, in order to optimize this emerging technology, simulative kinetic models have been developed with the aim of maximizing both energy efficiency and CO2 conversion. In the present paper, an overview of the most common non-thermal plasma technologies was carried out to highlight the advantages and disadvantages of each method. Then, an overview of the most significant kinetic models available in literature was carried out to point out the main reactions occurring during CO2 conversion and also the parameters that most affect the performance of a plasma reactor during CO2 conversion. Then, a brief recap of the literature available on economic studies of the plasma process is given.

New insights of MgCl2 attack to cement mortar in the condition of low air pressure

Almost all the studies about the deterioration of cement-based materials by chloride salts are conducted in the condition of curing and exposing the samples in the normal air pressure. In this study, Portland cement paste and mortar were firstly cured in the environment with low air pressure (60 kPa) and then transferred to the immersion in the10 wt.% MgCl2 solutions under the same air pressure up to 6 months. Experimental results revealed a new corrosion mechanism during the MgCl2-induced deterioration of semi-immersed mortar, i.e., the formation Mg2(OH)3Cl·4H2O with fireworks-like shaped (surface) and dandelion-like shaped (inside), leading to a nearly intact surface and cracked interior with peeling onion shape. Besides, the generation of Mg10(OH)18Cl2·5H2O with higher alkalinity in the full-immersed cement paste resulted from the presence of Mg(OH)2 layer on the surface. Two types of white sediments found on the surface of paste and mortar are respectively composed of Mg(OH)2 and M − SH detected by XRD, SEM/EDS, and TG-HDSC. Finally, the accumulation of MgCl2-induced corrosion products resulted in significantly deteriorations in pore structure as well as compromised compressive strength.

Fast preparation of Eu(BTB) MOFs in dielectric barrier discharge liquid plasma for luminescent sensing of trace iron.

Lanthanide metal-organic frameworks Eu(BTB) MOFs was synthesized in low-temperature plasma produced by dielectric barrier discharge (DBD). This DBD synthesis possesses the characteristics of rapid reaction (within 20 min), mild condition (low temperature and atmospheric pressure) and simple operation compared with many traditional synthesis methods. The prepared Eu(BTB) MOF material exhibits typical red light emitting of europium (Eu3+ ) at 617 nm, which can selectively and sensitively be quenched in the presence of trace iron(III) ion (Fe3+ ). A simple, fast and sensitive fluorescence sensing strategy of Fe3+ was thus constructed, with a limit of detection (LOD) of 0.5μM. Compared with reported fluorescence probes, Eu(BTB) MOFs have also demonstrated the advantages of low cost, easy and fast preparation, great stability, and excellent optical properties, thus making them a promising fluorescence candidate for trace Fe3+ sensing for the potential application in biological systems in the future.

The realization of autonomous, aircraft-based, real-time aerosol mass spectrometry in the upper troposphere and lower stratosphere

Abstract. We report on the developments that enabled the field deployment of a fully automated aerosol mass spectrometer, especially designed for high-altitude measurements on unpressurized aircraft. The merits of the two main categories of real-time aerosol mass spectrometry, i.e. (a) single-particle laser desorption and ionization and (b) continuous thermal desorption and electron impact ionization of aerosols, have been integrated into one compact apparatus with the aim to perform in situ real-time analysis of aerosol chemical composition. The demonstrated instrument, named the ERICA (European Research Council Instrument for Chemical composition of Aerosols), operated successfully aboard the high-altitude research aircraft M-55 Geophysica at altitudes up to 20 km while being exposed to ambient conditions of very low atmospheric pressure and temperature. A primary goal of those field deployments was the in situ study of the Asian tropopause aerosol layer (ATAL). During 11 research flights, the instrument operated for more than 49 h and collected chemical composition information of more than 150 000 single particles combined with quantitative chemical composition analysis of aerosol particle ensembles. This paper presents in detail the technical characteristics of the main constituent parts of the instrument, as well as the design considerations for its integration into the aircraft and its autonomous operation in the upper troposphere and lower stratosphere (UTLS). Additionally, system performance data from the first field deployments of the instrument are presented and discussed, together with exemplary mass spectrometry data collected during those flights.

Low viscosity of spinning liquid to prepare organic-inorganic hybrid ultrafine nanofiber membrane for high-efficiency filtration application

Particulate matter (PM) pollution is a global problem. It is of great significance to develop an advanced PM0.3 air filter. In this paper, the factors affecting the fiber diameter in spinning are discussed, and a kind of organic-inorganic hybrid ultrafine nano-fiber membrane with high-efficiency and low-pressure drop is prepared via utilizing low viscosity electrostatic spinning solutions. The viscosity of the spinning solution is diminished via reducing polyvinylidene fluoride (PVDF) mass fraction and adding hydrophobic silica (SiO2). In this way, the mean fiber diameter of the hybrid nanofiber membrane = 53.08 nm, mean pore size = 0.43 μm, and the surface potential is as high as 17.53 kV. Hence, the filtration efficiency of PM0.3 is as high as 99.997 %, and air pressure is comparatively low (only 114.46 Pa). In conclusion, PVDF-SiO2 fiber membrane can effectively accomplish high-efficient and low-pressure air filtration and can be widely used in various fields such as various masks and protective clothing.

Study on the Natural Ventilation Characteristics of a Solar Greenhouse in a High-Altitude Area

The ventilation rate of a greenhouse is one of the major factors to consider when assessing its ventilation performance. Compared with plain areas, high-altitude areas have lower air pressure, thinner air, and stronger solar radiation, which in turn affect the magnitude of the local greenhouse ventilation rate. This paper is based on the use of online monitoring and computational fluid dynamics (CFD) techniques for modeling and model validation. The average relative error (ARE), mean absolute error (MAE), root-mean-square error (RMSE), and determination coefficient (R2) of the temperature were 4.88%, 1.396 °C, 1.428 °C, and 0.9982, respectively. The ARE, MAE, RMSE, and R2 of the velocity were 9.525%, 0.035 m/s, 0.049 m/s, and 0.9869, respectively. Then, the distributions of the wind pressure, Reynolds number (Re), thermal pressure, air density, air speed, and temperature in greenhouses in high-altitude and plain areas were researched to obtain the relevant factors affecting the ventilation rates of greenhouses in high-altitude areas. In addition, correlation analyses were conducted for five variables affecting the ventilation rate: the inlet velocity, the temperature difference between the inside and outside of the greenhouse, the air density difference between the inside and outside of the greenhouse, total indoor radiation, and the internal heat source of the crop, and the coefficients of their correlations with the greenhouse ventilation rate were 1.0, −0.83, −0.72, −0.72, and 0.68, respectively. A natural ventilation rate model for plateau areas was developed, with the ARE, RMSE, and R2 between the sample values and fitted values determined to be 4.55%, 0.543 m3/s, and 0.9997, respectively. The model was validated by predicting the greenhouse ventilation rate in winter (3 January 2022), and the ARE, RMSE, and R2 of the sample values and predicted values were 9.726%, 8.435 m3/s, and 0.9901, respectively. This study provides a theoretical basis for further research on greenhouse ventilation characteristics in high-altitude areas.

Blizzard in a box [Environment Testing

Until recently, the only way to find out what happened to anything in extreme cold, or heat, or at low atmospheric pressures, was to take it somewhere suitably extreme and run tests on site - and this was for large-scale testing. This, however, is expensive, often perilous, and hit-and-miss when it comes to the replication or control of variables. Although small-scale environmental testing within specially designed chambers has been around for decades, solar panels, technical clothing, drones, bulldozers and even humans, plants and other living things can now all be tested to their limits at a facility in Bolzano in the Italian Tyrol.

Association between meteorological factors and elderly falls in injury surveillance from 2014 to 2018 in Guangzhou, China

IntroductionWith rapid increase in the aging population, falls injuries have become an important public health problem. However, limited data have been reported on the associations between meteorological factors and falls injuries in the elderly. This study assessed the epidemiology of falls injuries and explored this association in the elderly in Guangzhou, China. MethodsData on elderly falls injury cases and meteorological variables from 2014 to 2018 in Guangzhou were collected from the Guangzhou Injury Monitoring System and Guangzhou Meteorological Bureau, respectively. The monthly average data on falls injuries and meteorological factors were applied to the data analysis. These correlations were conducted using Pearson correlation analysis. A multiple linear regression model was used to estimate the effects of meteorological factors on falls injuries in the elderly in Guangzhou, China. ResultsAccounting for 49.41% of causes of elderly injury were falls in the Guangzhou Injury Monitoring System from 2014 to 2018, which occupied first place for five consecutive years. The monthly number of elderly falls injury cases was lowest in April and highest in December, and had a positive correlation with monthly mean wind speed (r = 0.187, P < 0.01) and a negative correlation with monthly atmospheric pressure (r = -0.142, P < 0.05). A multiple linear regression model was constructed (F = 10.176, P < 0.01), which explained 23.7% of the variances (R2 = 0.237). Monthly mean wind speed (β = 76.85, P < 0.01) and monthly mean atmospheric pressure (β = −3.162, P < 0.01) were independent factors affecting monthly elderly falls injuries. ConclusionsFalls are the primary cause of injury among elderly people in Guangzhou, China. Meteorological factors are related to falls injuries in the elderly population. Decreasing activity during high wind and low atmospheric pressure weather may help reduce the number of elderly falls injury cases.

The role of low pressures in the moisture transport of intense rains,

Abstract: Heavy rain is one of the environmental hazards at the province of Sulaymaniyah and Halabja; It is made on account of the movement of atmospheric low pressure and Trough, the aim of this research is to know and showing the role of atmospheric low pressure and Trough for making the heavy rain and How to transfer their Humidity. The result shows that at mid air level (500hp) the creation of a trough in the form of deep and wide were formed, and at the surface level the merging both low pressure of (Sudan and The Mediterranean), both of them are a reason for heavy rain, and transfer of humidity. As well, it proven that (90%) heavy rains Humidity transfer from level (700hp) and lower. In a way that, most of humidity at the level (950hp) transfers from Arab and Oman Sea, Adan and Arab Gulfs, and at the level (850hp) most of humidity comes from the Red and Arab Sea, Gulf of Aden and at the level (700hp) most humidity comes from Red and Mediterranean Sea to research area. Key word: Humidity, Low pressure, Heavy Rain, Synoptic

The Precursors of High Rainfall Intensity During June in Southern Central Java: A Case Study of Flash Floods 18 June 2016 in Purworejo

High rainfall intensity during the dry season can cause floods and landslides that cause a lot of loss of property and life as happened in Purworejo. Generally, the dry season with little rainfall, heavy rain in June is very rare, therefore disaster anticipation will be better if the precursor can be identified. This research aims to obtain high-intensity rain precursors in the south of Central Java, especially Purworejo. Identification used classifying rainfall for 10 years and related to atmospheric phenomena that impact to Indonesian rainfall variability. The results show that if there are very heavy rainfall and evenly distributed, precursors, can be identified in 3 days before the incident such as low OLR which value of &lt;150 Wm-2. Moreover, an analysis of the average 3 days before the incident, the value of the OLR anomaly in the Central Java region is between –20 to –60 Wm-2. Meanwhile, the vertical humidity profile with more than 80% reached the 500 mb level, as well as spots where the temperature was more than 30.20C, three to four days before the incident with a value of more than 30.20C in the Indian Ocean adjacent to the southern part of Java Island. Existing low air pressure in the northern part of Kalimantan and in the southern part of Java, which persists for a long time, can support very heavy rains in June in Purworejo. Especially if the wind speed decreases to less than 4 m/s and occurs in phases 3 and 4 of the MJO.

Corrosion of metal parts on satellites by iodine exposure in space

Iodine becomes increasingly popular as alternative propellant for electric propulsion (EP) systems offering several advantages over established xenon. However, iodine is also a reactive and corrosive element. Thus, a careful material selection for the EP system itself, but also for components employed on the satellite is required in the light of typical space mission durations of several years. Here, we carefully define an approach for mimicking long-term interaction of material specimens with iodine in a space environment. The space conditions cover typical iodine atmospheres (10− 1 to 10− 4 Pa), which occur in the vicinity of a satellite employing an iodine-fed EP system, and exposure times, which correspond to 10 years of mission duration. The approach is used to expose a wide range of metal specimens commonly used on spacecraft to iodine. Chemical modifications of the surfaces of the treated samples are analyzed by x-ray photoelectron spectroscopy (XPS). The elemental metals Fe, Ti, Al, and Nb chemically react with iodine, whereas the elemental metals Ni, Cr, Ta, W, and Mo are basically inert. The stainless-steel and aluminum metal alloys show the same behavior as the corresponding dominant elemental specimens, i.e., Fe and Al, respectively. Somewhat surprisingly, Cr as constituent in stainless steel reacts with iodine, in contrast to elemental Cr. Nevertheless, our studies reveal that long-term exposure to low-pressure iodine atmospheres is not critical for the macroscopic structural integrity of all tested specimens even over space mission durations of several years. The reaction with iodine is macroscopically a surface effect, which mainly affects the optical appearance.

Environmental Factors in Northern Italy and Sickle Cell Disease Acute Complications: A Multicentric Study.

Background: Environmental factors seem to influence clinical manifestations of sickle cell disease (SCD), but few studies have shown consistent findings. We conducted a retrospective multicentric observational study to investigate the influence of environmental parameters on hospitalization for vaso-occlusive crises (VOC) or acute chest syndrome (ACS) in children with SCD. Methods: Hospital admissions were correlated with daily meteorological and air-quality data obtained from Environmental Regional Agencies in the period 2011–2015. The effect of different parameters was assessed on the day preceding the crisis up to ten days before. Statistical analysis was performed using a quasi-likelihood Poisson regression in a generalized linear model. Results: The risk of hospitalization was increased for low maximum temperature, low minimum relative humidity, and low atmospheric pressure and weakly for mean wind speed. The diurnal temperature range and temperature difference between two consecutive days were determined to be important causes of hospitalization. For air quality parameters, we found a correlation only for high levels of ozone and for low values at the tail corresponding to the lowest concentration of this pollutant. Conclusions: Temperature, atmospheric pressure, humidity and ozone levels influence acute complications of SCD. Patients’ education and the knowledge of the modes of actions of these factors could reduce hospitalizations.

Drift characteristics and the multi-field coupling stress mechanism of the pantograph-catenary arc under low air pressure

The fault caused by a pantograph-catenary arc is the main factor that threatens the stability of high-speed railway energy transmission. Pantograph-catenary arc vertical drift is more severe than the case under normal pressure, as it is easy to develop the rigid busbar, which may lead to the flashover occurring around the support insulators. We establish a pantograph-catenary arc experiment and diagnosis platform to simulate low pressure and strong airflow environment. Meanwhile, the variation law of arc drift height with time under different air pressures and airflow velocities is analyzed. Moreover, arc drift characteristics and influencing factors are explored. The physical process of the arc column drifting to the rigid busbar with the jumping mechanism of the arc root on the rigid busbar is summarized. In order to further explore the mechanism of the above physical process, a multi-field stress coupling model is built, as the multi-stress variation law of arc is quantitatively evaluated. The dynamic action mechanism of multi-field stress on arc drifting characteristics is explored, as the physical mechanism of arc drifting under low pressure is theoretically explained. The research results provide theoretical support for arc suppression in high-altitude areas.

SAFETY OF THE USE OF HIGH-ALTITUDE PROTECTION SUITS IN PATIENTS WITH NEUROLOGICAL DISORDERS IN KINESITHERAPY

HAP (High-Altitude Protection) suits were originally developed to protect the bodies of flight personnel from the effects of low atmospheric pressure. At a later stage of their development, they were supplemented with a system to prevent the negative effects of gravitational acceleration. A new and very different application of HAP suits is their use in the kinesitherapy process for patients with neurological deficits. However, due to the possibility of cardiovascular overload and a potentially dangerous increase in blood pressure, studies have been conducted to observe the occurrence of increased blood pressure. The study was conducted on a group of 39 patients with various neurological deficits during a fiveoccupation therapy session. Previously published results obtained for 17 healthy subjects (control group) were used for comparison [2]. The WUK 90 version of the HAP suit was used during the therapy. The compared results for the control and experimental groups are similar to each other AND show no increase in blood pressure.

Dynamic simulation of a Re-compressed adiabatic compressed air energy storage (RA-CAES) system

In this work, a novel re-compressed adiabatic compressed air energy storage (RA-CAES) system is proposed to raise the operating pressure of the expansion train. In the discharging process, a compressor is employed to enhance the low-pressure air from storage vessels to the operating pressure. Off-design models for components have been established and experimental data available in the open literature are adopted for validation. Potential induced degradation (PID) control technology is employed to control the outlet temperature of the air in inter-cooling and after-cooling heat exchangers. The calculation results for the components have been presented and discussed. Meanwhile, the system performances of the proposed RA-CAES are compared with that of conventional A-CAES. The comparison results show the round trip efficiency (RTE) of RA-CAES is 69.89%, while it is only 65.23% for A-CAES, and the increment of RTE between A-CAES and RA-CAES is 4.66%. The influence of isentropic efficiencies of turbine and compressor is also investigated, the RTE of RA-CAES is always higher than that of A-CAES, and the minimum increment of RTE is near 4%. Overall, this study presents valuable insights into the design of A-CAES, the proposed RA-CAES is more efficient than the conventional A-CAES.