Low Atmospheric Pressure Research Articles

Modeling dust emission in alpine regions with low air temperature and low air pressure – A case study on the Qinghai-Tibetan Plateau (QTP)

• Variations of temperature and pressure could impact dust emission process. • Air density is an important parameter in dust emission modeling. • The improved model could simulate precisely the dust emission in the QTP. • The dust emission in the QTP mainly occurred in winter and early spring. Dust emission is one of the important segments of the circulation of materials between lithosphere, atmosphere, and ocean systems. However, studies on dust emission have mainly concentrated on arid and semiarid regions with few studies focused on dust emission in alpine areas, where having lower air temperatures and lower air pressure environments. The lower air temperature and lower air pressure could significantly impact the air density and make the entrainment and transport of dust different from those at lower altitudes. The lack of accurate studies on dust emission in alpine regions has resulted in large uncertainties in the global dust budget and brought large challenges in controlling aeolian hazards in alpine regions. To bridge this gap, we took the air density as an important parameter to simulate dust emission in the Qinghai-Tibetan Plateau (QTP), where has typical low air-temperature and low air-pressure environments. The measured data showed that the lower air temperature and low air pressure affect the particle size distributions (PSDs) of aeolian sediment, the threshold velocity (TFV) as well as the dust emission rate. Herein, we introduced air density as an important factor to improve a dust emission model, and the validated results showed that the deviations of the simulated horizontal sand flux and vertical dust flux were less than 30% and 35%, respectively. Using the improved model, we could exactly depict the spatial and temporal distribution of dust emission in the QTP. The results shown, our model could exactly depict the spatial and temporal distribution of dust emission in the QTP. We believe that the improvement of the model could offer a new perspective on dust emission in environments with lower air temperature and lower air pressure, and the simulated results could provide valuable data for global dust budget estimation.

A numerical study on CO migration after blasting in high-altitude tunnel by inclined shaft

On the western plateau of China, ventilation problems brought on by low atmospheric pressure must be overcome. And CO migration after blasting in high-altitude tunnel by inclined shaft has become a significant scientific issue. In this study, the Computational Fluid Dynamics (CFD) method was used to analyze the flow field characteristics at the junction of the inclined shaft and tunnel. In addition, the effects of different fan opening modes and different initial CO concentration distributions on the ventilation were discussed. The simulation results showed that the main difference in the ventilation wind field was reflected in the position of the vortex region due to the different fan opening modes. Meanwhile, various initial CO concentration distributions showed different migration when there was no air volume difference between the left and right tunnels. Eliminating vortex zones and fully using high velocity airflow could improve relative ventilation efficiency by at least 18%. CO would accumulate in the opposite direction of the tunnel if only one of the fans was turned on. Therefore, a two-stage ventilation scheme was proposed, and the energy consumption was reduced by at least 33%. This research can provide guidance on high-altitude tunnel construction with multiple working faces to improve ventilation efficiency and reduce energy consumption.

Flat plate pressure impact on a still water surface: The effect of surrounding ambient pressure and plate size

The study of the impact between a rigid structure and water has raised the interest of many researchers in these recent years. This problem is relevant to various engineering applications, and particularly in the nautical environment (renewable energy, marine applications...). The present paper details an experimental investigation of rigid circular plates impacts into pure water. The analyses are based on impact pressure temporal signals, pressure impulses and frequency analysis recorded while the plates were impinging the still water surface. The measurement campaigns were carried out at the University Le Havre Normandy’s LOMC laboratory, in a recently developed experimental facility. In the previous experimental and numerical studies, it was observed that the magnitude of the peak slamming pressure is reduced if compared to the theoretical model predicted by von Karman (1929). Similar observations were made here and the decrease was partly attributed to the cushion effect resulting from the presence of an entrapped air layer between the rigid plate and the water free surface. This work aims to study the influence of the cushion effect on the impact pressure by using four rigid circular plates with different diameters in order to modify the volume of the air layer. Initially, the measurements were carried out for an ambient pressure equal to the atmospheric pressure. In a second part of the study, the same measurements were performed for two lower ambient pressures (about 75% and 50% of the atmospheric pressure) in order to minimise the cushion effect. And finally, a frequency analysis is presented with comparisons to theoretical results of Minnaert (1933) in order to correlate the air layer size to the pressure oscillation characteristics. The obtained results were compared with previous experimental and theoretical studies for low impact velocities (V≤1.2 m/s).

The influence of overcharge and discharge rate on the thermal safety performance of lithium-ion battery under low air pressure

The influence of overcharge and discharge rate on the thermal safety performance of lithium-ion battery under low air pressure

Sulfur mass-independent fractionation during SO2 photolysis in low-temperature/pressure atmospheres

Mass-independent fractionation of sulfur isotopes (MIF-S) has been observed in Archean sedimentary rocks and modern stratospheric sulfate aerosol (SSA). Photolysis of SO2 is known to cause significant MIF-S and could be related to the observed MIF-S. However, previous experiments with SO2 photolysis at room temperature, or at low temperatures and atmospheric pressure, did not quantitatively explain quadruple sulfur isotopic compositions (δ34S, Δ33S, and Δ36S values) of the Archean sedimentary rocks and the modern SSA. Here we describe sulfur isotopic fractionation during SO2 photolysis including isotopic self-shielding at low temperatures (down to 228 K) and low pressures (from 5.9 to 9.8 kPa) where pressure broadening of SO2 becomes negligible. Results indicate that magnitudes of sulfur isotopic fractionation factors (34ε, 33E, and 36E values, where 33E = 33ε – 1000 × [(1 + 34ε/1000)0.515 − 1] and 36E = 36ε − 1000 × [(1 + 36ε/1000)1.90 − 1]) increase with decreasing temperature, with values at 228 K being about four times those at 296 K (34ε of up to +344‰). Meanwhile, 33E/34ε and 36E/33E ratios are roughly independent of temperature over the temperature range (by approximately +0.1 and − 3.1, respectively), although the 33E/34ε ratios slightly increase with decreasing temperature, ranging from ~ + 0.08 to ~ + 0.13. A two-component mixing model involving SO2 oxidation by OH and SO2 photolysis in the stratosphere reproduces δ34S and Δ33S values of modern SSA when the contribution ratio of SO2 photolysis to SO3 production is ~20%. The contribution ratio of ~20% is consistent with a previous estimation by Whitehill et al. (2015). However, Δ33S/δ34S ratios at low temperatures are far from those of Archean sedimentary rocks, calling for an additional mechanism (or mechanisms) to explain Archean MIF-S.

Green carboxylation of CO2 triggered by well-dispersed silver nanoparticles immobilized by melamine-based porous organic polymers

CO2 fixation via directly formation of C-C bonds to obtain carboxylation compound is an essential reaction in industry. Creating efficient, inexpensive and industrially valuable key catalysts have always been a desire, but also an urgent challenge. Here, we synthesized a kind of melamine-based porous organic polymers (POPs) evenly loaded Ag Nanoparticles (Ag NPs/Melamine-based POPs) by the gas bubbling-assisted membrane reduction (GBMR) approach. The melamine-based POPs were used as good nitrogen-rich supports for loading and dispersing Ag nanoparticles. Ag NPs/ melamine-based POPs exhibited good CO2 absorption capacity (2.1 mmol/g, 273 K and 0.1 MPa) and the excellent activity was up to 93% towards the carboxylation of terminal alkynes with CO2 under mild reaction conditions (323 K, 0.1 MPa). And the TOF is 2.23 h−1. Specially, this is very few report of heterogeneously catalyzed directly formation of carboxylation compound only applying terminal alkynes with CO2 under low temperature and atmospheric pressure. The mechanistic study revealed that the well-dispersed Ag active species promoted highly efficient and green conversion of CO2. Moreover, the catalyst was easily recovered and could be reused at least six times with retention of high catalytic activity.

A novel boil-off gas reliquefaction system using liquid air for intercontinental liquefied natural gas transportation

The boil-off gas (BOG) reliquefaction of cryogenic liquefied natural gas (LNG) for its intercontinental transport is challenging. This paper proposes a novel BOG reliquefaction system using liquid air and two different process designs: (i) low-pressure liquid air (LPLA) and (ii) high-pressure liquid air (HPLA). In the proposed system, an open refrigeration system using liquid air reliquefies BOG, thereby replacing the current commercial closed refrigeration cycle. As the temperature of liquid air is in the cryogenic range, the energy consumption to reliquefy BOG onboard approaches zero. However, the additional total weight of the ship is required to store liquid air, thus necessitating increased propulsion energy. Nevertheless, the reduction in energy needed for BOG reliquefaction exceeds the energy requirement for the added engine load. Thus, the LPLA shows a massive energy reduction from 4,913.07 to 642.67 kW compared to the commercial BOG reliquefaction process involving the nitrogen expander cycle. The HPLA process shows further improved results of 436.34 kW by expanding the vaporized high-pressure air. In addition, the proposed HPLA design exhibits an exergy efficiency of 77.4 %, which is 37.6 % higher than that of the commercial nitrogen expander process. A techno-economic analysis, including the purchase and transport cost of liquid air, is conducted to reflect an effort on on-shore liquid air production and transportation. Despite the additional liquid air tanks, the overall process configuration is much simpler than that of the current commercial BOG reliquefaction system. Thus, the proposed HPLA process is more economical than commercial processes for all representative voyage duration scenarios (8, 13, and 21 days).

Influence of Meteorological Temperature and Pressure on the Severity of Heart Failure Decompensations.

To investigate the relationship between ambient temperature and atmospheric pressure (AP) and the severity of heart failure (HF) decompensations. We analysed patients coming from the Epidemioloy Acute Heart Failure Emergency (EAHFE) Registry, a multicentre prospective cohort study enrolling patients diagnosed with decompensated HF in 26 emergency departments (EDs) of 16 Spanish cities. We recorded patient and demographic data and maximum temperature (Tmax) and AP (APmax) the day before ED consultation. Associations between temperature and AP and severity endpoints were explored by logistic regression. We used restricted cubic splines to model continuous non-linear associations of temperature and AP with each endpoint. We analysed 16,545 patients. Daily Tmax and APmax (anomaly) of the day before patient ED arrival ranged from 0.8 to 41.6° and from - 61.7 to 69.9 hPa, respectively. A total of 12,352 patients (75.2%) were hospitalised, with in-hospital mortality in 1171 (7.1%). The probability of hospitalisation by HF decompensation showed a U-shaped curve versus Tmax and an increasing trend versus APmax. Regarding temperature, hospitalisation significantly increased from 20 °C (reference) upwards (25 °C: OR = 1.12, 95% CI = 1.04-1.21; 40 °C: 1.65, 1.13-2.40) and below 5.4 °C (5 °C: 1.21, 1.01-1.46). Concerning the mean AP of the city (anomaly = 0 hPa), hospitalisation increased when APmax (anomaly) was above + 7.0 hPa (atmospheric anticyclone; + 10 hPa: 1.14, 1.05-1.24; + 30 hPa: 2.02. 1.35-3.03). The lowest probability of mortality also corresponded to cold-mild temperatures and low AP, with a significant increased risk only found for Tmax above 24.3 °C (25 °C: 1.13, 1.01-1.27; 40 °C: 2.05, 1.15-3.64) and APmax (anomaly) above + 3.4 hPa (+ 10 hPa: 1.21, 1.07-1.36; + 30 hPa: 1.73, 1.06-2.81). Sensitivity analysis confirmed the main analysis results. Temperature and AP are independently associated with the severity of HF decompensations, with possible different effects on the need for hospitalisation and in-hospital mortality.

Experimental Simulation of Red Sprites in a Laboratory

Over the past three decades, research of high-altitude atmospheric discharges has received a lot of attention. This paper presents the results of experimental modeling of red sprites during a discharge in low-pressure air. To initiate ionization waves in a quartz tube, an electrodeless pulseperiodic discharge fed by microsecond voltage pulses with an amplitude of a few kilovolts and a repetition rate of tens of kHz were formed. In this case ionization waves (streamers) have a length of tens of centimeters. The main plasma parameters were measured at various distances along the tube. The measurements confirm the fact that ionization waves propagate in opposite directions from the zone of the main electrodeless discharge, just as it happens during the formation of red sprites.

Increased Risk of Hospital Admission for Asthma from Short-Term Exposure to Low Air Pressure

PurposeAsthma has a major impact on patients’ quality of life, mortality, and healthcare burden. Some evidence suggests that environmental factors may trigger asthma. However, there has been limited research on the relationship between air pressure and asthma hospital admissions, especially in China. Thus, we aimed to study the influence of air pressure and identify potentially susceptible populations.MethodsThe study data were gathered from hospitalization records with a primary diagnosis of asthma from all secondary and tertiary hospitals in Beijing from January 1, 2013, to December 31, 2016. The study examined the association between the risk of asthma and air pressure using a distributed lag non-linear model (DLNM). We also performed a stratified analysis to identify the susceptible populations.ResultsA total of 23,697 asthma hospital admissions were included in the study. We found that the relative risk (RR) and the 7-day cumulative relative risk (CRR) of asthma had an approximate negative correlation with air pressure. At the same time, we found that the association was most apparent on the day of exposure (lag = 0).ConclusionAmbient air pressure had an approximately negative correlation with daily asthma hospital admissions in Beijing, China. That means the risk of hospital admission for asthma would be increased by low air pressure. Furthermore, air pressure has a significant effect on asthma only on the day of exposure. It is possibly significant to protect the vulnerable on days with low air pressure, especially those younger than 65 years.

Minimum ignition energy of hydrogen-air and methane-air mixtures at temperatures as low as 200 K

The primary objective of this study is to measure the minimum ignition energy (MIE) of methane-air and hydrogen-air mixtures at low temperatures and atmospheric pressure. Initial fuel-air mixture temperatures as low as 200 K were considered, for a constant equivalence ratio of 1.0 for methane-air and 0.16 for hydrogen-air. The ignition source was a spark, generated by a high-voltage pulse of 100 μs duration, applied on two pin electrodes of 0.1-mm diameter, separated by a gap distance of 1 mm. The experimental methodology was validated by comparing the results obtained with those from previous studies available in the literature. First, for methane-air mixtures, the MIE as a function of the equivalence ratio followed the same trend at 295 K and 255 K, i.e., its lowest value was obtained for a stoichiometric mixture. Second, when the temperature of the mixture was decreased, the MIE increased linearly for both fuels. The rate at which the MIE changed was higher for hydrogen-air (−7.9 μJ/K) than for methane-air (−3.4 μJ/K). Overall, this study provides valuable information on the MIE of methane-air and hydrogen-air mixtures at low temperatures, which can be useful for the design of cryogenic fuel storage systems.

Correlating atmospheric pressure and temperature with Meniere attack

ObjectiveThis paper correlated the Meniere attack with meteorological parameters i.e. atmospheric pressure, temperature, relative humidity and rainfall, to investigate which parameters that trigger the Meniere attack. MethodsDuring the past three years, totally 283 (2015), 351 (2016) and 319 (2017) patients with Meniere's disease (MD) were encountered at a clinic of the university hospital, accounting for 13%, 17% and 16% incidence in relation to overall annual neurotological cases, respectively. The onset of Meniere attack was then correlated with meteorological parameters. ResultsThe mean seasonal incidence of Meniere attack in relation to overall seasonal neurotological cases in 2015-2017 were 14.8 ± 2.8% (spring), 17.5 ± 2.2% (summer), 16.0 ± 1.8 % (autumn) and 12.8 ± 2.0% (winter), indicating that summer season had a higher incidence of Meniere attacks than winter season. Onset of Meniere attacks correlated significantly with the atmospheric pressure (r = -0.4484, p = 0.0061) and temperature (r = 0.4736, p = 0.0035), and the atmospheric pressure was highly negatively correlated with the temperature (r = -0.9421, p < 0.0001). In contrast, no correlation was identified between the onset of Meniere attacks and relative humidity or rainfall. The atmospheric pressure in the same month with typhoon compared with that without typhoon revealed a median reduction of 13.1 hectopascal. ConclusionAtmospheric pressure and temperature are correlated with the onset of Meniere attack. Summer season has a higher incidence of Meniere attack than winter season, likely because low atmospheric pressure in summer may aggravate endolymphatic hydrops, especially when accompanied by typhoons in the northwest Pacific region.

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.

Ionization states for the multipetawatt laser-QED regime

A paradigm shift in the physics of laser-plasma interactions is approaching with the commissioning of multipetawatt laser facilities worldwide. Radiation reaction processes will result in the onset of electron-positron pair cascades and, with that, the absorption and partitioning of the incident laser energy, as well as the energy transport throughout the irradiated targets. To accurately quantify these effects, one must know the focused intensity on target in situ. In this work, a way of measuring the focused intensity on target is proposed based upon the ionization of xenon gas at low ambient pressure. The field ionization rates from two works [Phys. Rev. A 59, 569 (1999)1050-294710.1103/PhysRevA.59.569 and Phys. Rev. A 98, 043407 (2018)2469-992610.1103/PhysRevA.98.043407], where the latter rate has been derived using quantum mechanics, have been implemented in the particle-in-cell code SMILEI [Comput. Phys. Commun. 222, 351 (2018)0010-465510.1016/j.cpc.2017.09.024]. A series of one- and two-dimensional simulations are compared and shown to reproduce the charge states without presenting visible differences when increasing the simulation dimensionality. They provide a way to accurately verify the intensity on target using in situ measurements.

Facile synthesis of mesoporous ZSM-5 aided by sonication and its application for VOCs capture

Application of ultrasound power to the mother liquor is popular pretreatment for zeolite synthesis which offers a simple way of accelerating crystallization process and finetuning the properties of nanocrystalline zeolites. In this work, sonication-aided synthesis of mesoporous ZSM-5 at low temperature and ambient pressure was systematically studied, in an attempt to reach efficient and benign synthesis of zeolites with hierarchical pore structure, which has wide applications as catalysts and sorbents. The effects of sonication duration, power density, sonication temperature and seeding on the crystallization of ZSM-5 were investigated. The obtained samples were characterized by XRD, SEM, BET and VOCs capture. High quality mesoporous ZSM-5 can be obtained by a facile 5 d synthesis at 363 K, much faster than conventional hydrothermal synthesis. The reduced synthesis time was mainly attributed to the enhanced crystallization kinetics caused by the fragmentation of seeds and nuclei, while sonication radiation had little impact on the nucleation process. Compared with control sample, mesoporous ZSM-5 prepared by sonochemical method had higher surface area and mesoporosity which demonstrated improved adsorption performance for the capture of isopropanol.

Relationship between the East Atlantic teleconnection pattern and the spring dust storm in northern China. Part‐I: Impacts of components of the atmospheric circulation over Eurasia on dust storm dynamic power—Spring gales

AbstractSpring gale is a dynamic power for DSs (DSs), which presents a close connection with the DSs of northern China. Both display declining trends during the past 68 years (1954–2021). In this study, the influencing factors of spring gales and DSs around northern China and possible adjustment functions of the East Atlantic (EA) teleconnection pattern have been investigated. It was found that the major systems controlling spring gales include the North Polar vortex (NPV), mid–high‐latitude blocking highs (BHs), air pressure status of the Tibetan Plateau (TP) over the Eurasian continent, India–Burma trough (IBT) and western Pacific subtropical high (WPSH). Under synthetic atmospheric circulation conditions of an enlarged NPV, lower air pressure over the TP, a strong IBT, and a southeastward‐retreated WPSH, spring gales increase, and the frequency of DS occurrence is increased, and vice versa. Additionally, spring gales are also negatively affected by BHs. The most important is the Baikal BH, which has influence not only in previous seasons but also in the contemporary spring. Furthermore, the NPV and IBT have close negative correlation with the EA pattern, whereas the TP and WPSH have positive correlation with the EA pattern both in previous seasons and in the contemporary spring. A high‐pitched EA pattern results in a strong western current north of Lake Baikal, which may prohibit the expansion of the NPV in the sector of northern China. A shrunk NPV means infrequent cold air attacks and decreased gales and DSs.

Review article: Atmospheric Pressure, Water with Air, Porosity and Strength of Concrete (In memory of Professor László A Gömze)

The review shows that the gas content in tablets and solutions of medicines can significantly change their physical and chemical properties, qualitative and quantitative characteristics of the mechanism of action of medicines when applied topically, and even allows you to turn “old” and known medicines into “new” medicines with completely new and previously unknown mechanisms of action. Therefore, artificial changes in the gas content in solid and liquid dosage forms were recommended as an original method of developing new drugs. It has been shown that this method is particularly promising for the development of new antiseptic, cosmetic and hygiene products. The fact is that the additional forced introduction of gas into a liquid or into solid through excessive pressure increases their volume, reduces their specific gravity and strength. Moreover, it allows you to “blow up” them by cold boiling. Conversely, the removal of gas from them due to vacuum reduces the volume, increases the specific gravity and strength. By analogy with the change in the physical and chemical properties of liquid and solid medicines, achieved by removing gases from them, it is proposed to reduce the porosity and volume of concrete and increase its specific weight and strength by degassing the water used for wetting cement in the concrete manufacturing process. Due to the fact that under normal conditions, the gas content in the water used for the manufacture of concrete directly depends on the atmospheric pressure, it is concluded that the production of concrete at different atmospheric pressure changes its quality. In particular, low atmospheric pressure can reduce the porosity and volume of concrete, as well as increase the specific gravity and strength of concrete. On the other hand, high air and/or gas pressure can increase the porosity and volume of concrete and reduce the concrete’s specific gravity and strength. Therefore, the amount of atmospheric pressure and/or air and/or gas pressure on concrete during its production should be included in the list of controlled indicators of concrete manufacturing technology.

New Craters on Mars: An Updated Catalog

AbstractWe present a catalog of new impacts on Mars. These craters formed in the last few decades, constrained with repeat orbital imaging. Crater diameters range from 58 m down to &lt;1 m. For each impact, we report whether it formed a single crater or a cluster (58% clusters); albedo features of the blast zone (88% halos; 64% linear rays; 10% arcuate rays; majority dark‐toned; 4% light‐toned; 14% dual‐toned); and exposures of ice (4% definite; 2% possible). We find no trends in the occurrences of clusters with latitude, elevation, or impact size. Albedo features do not depend on atmospheric fragmentation. Halos are more prevalent at lower elevations, indicating an atmospheric pressure dependence; and around smaller impacts, which could be an observational bias. Linear rays are more likely to form from larger impacts into more consolidated material and may be enhanced by lower atmospheric pressure at higher elevations. Light‐ and dual‐toned blast zones occur in specific regions and more commonly around larger impacts, indicating excavation of compositionally distinct material. Surfaces covered with bright dust lacking cohesion are favored to form detectable surface features. The slope of the cumulative size frequency distribution for this data set is 2.2 for diameters &gt;8 m (differential slope 2.9), significantly shallower than the slope of new lunar craters. We believe that no systematic biases exist in the Martian data set sufficient to explain the discrepancy. This catalog is complete at the time of writing, although observational biases exist, and new discoveries continue.

Effect of Pretreatment and Storage Room Air Pressure on Quality Attributes Changes of Paprika (Capsicum annuum L.)

Paprika is a perishable commodity either physically, mechanically, or microbiologically which greatly affects product quality during storage. A combination of pretreatments and low air pressure storage (hypobaric) can greatly reduce metabolic rate and possibly maintain better product quality during storage. The purpose of this study was to analyze the combined effects of pretreatments and hypobaric storage on the quality attributes of paprika consisting of skin color, soluble solids content, and acidity during storage. The pretreatments used were UV-C exposure at 3.0 kJ/m2, ozone gas exposure at 4.99 ppm, and control or without pretreatment before storage. While the hypobaric pressures used were 26 kPa (O2 concentration 5%), 64 kPa (O2 concentration 13%), and 101 kPa (O2 concentration 21%). Paprika quality was measured daily for 15 days of storage. The results showed that storage time and the interaction of storage time and hypobaric pressure were found to have a significant effect on the chroma, hue angle, color difference, solid soluble content, and acidity. Hypobaric pressure was known to be more influential than pretreatment before storage. In general, storage in a hypobaric condition resulted in better quality attributes of the samples than control.

Rainfall Prediction from Himawari-8 Data Using the Deep Learning Method

Changes in rainfall affect human activities and can cause natural disasters, such as floods and landslides. This research focuses on changes in extreme rainfall that result in natural disasters. Indonesia, as a country with a tropical climate, certainly has its characteristics regarding rainfall patterns, such as air temperatures that tend to be high, sunlight that occurs throughout the year, and low air pressure. The characteristics of the tropical climate will form patterns and allow natural disasters to occur. Losses due to natural disasters can be minimized if there is thorough preparation in dealing with the possibility of natural disasters. Thorough preparation in facing natural disasters is based on knowledge of predictions of when and where the natural disaster will occur. Changes in rainfall can be predicted based on past rainfall data. These data produce patterns, such as real-time intensity. The data used in this research comes from the himawari-8 satellite using a cloud dataset. The next stage is pre-processing, which is the cleaning and adjustment of data. The deep learning algorithms used in this research are long short-term memory (LSTM) and recurrent neural network (RNN) to manage time series data. In previous research, it has been recommended that LSTM and RNN algorithms be used for rainfall prediction. The system created in this research is a rainfall prediction model using python programming language analysis and system output in the form of software with the accuracy of the LSTM model reaching 92.62% and the RNN model reaching 89.38%.