Experimental Study on Oxygen Supply Performance Influence Factors of Potassium Superoxide Oxygen Board Used in Confined Space

Experimental Study of the Gas Leakage and Optimized Supply of Oxygen in Coal Mine Refuge Chamber

The refuge chamber provides a safe space where people can stay safe when they are trapped by an accident in a coal mine. The refuge chamber includes several systems such as oxygen supply, air purification, cooling, and dehumidifying. The oxygen supply system is the core of the refuge chamber because it is a closed environment. The oxygen supply time is 96 h according to the relevant standards in America and China. If people stay in the refuge chamber for more than 96 h, the oxygen supply may not be enough, and they can be in danger. It is necessary to efficiently use oxygen and extend the oxygen supply time. Based on the experimental platform of the refuge chamber, this paper conducts an in-depth study on the automatic control of the oxygen supply system. The oxygen supply system and the harmful gas removal system can be automatically and efficiently controlled by the programmable logic controller (PLC) according to the personnel number and the oxygen concentration. The experiment has proved that the system is good and reliable.

In vitro rates of gross and net oxygen production were measured as a function of light intensity in some plankton communities collected from Bedford Basin, Nova Scotia, and in a monoclonal culture of Synechococcus . The rate of gross oxygen production was measured by a technique in which the stable oxygen isotope, 18 O, serves as a photosynthetic tracer Net oxygen production was measured by automated Winkler technique. The rate of community respiration in the light was then determined by the difference between gross and net rates of oxygen production. In the natural populations examined, neither gross nor net oxygen production rates were significantly inhibited at the highest light intensity measured (500–800 μE m −2 s −1 ) In a sample in which the dark respiration rate was small relative to the maximal rate of production [P max;sensu Platt et al (1980) J Mar. Res ., 38, 687–701] the rates of 'light' respiration were ∼3 times greater. In two other communities, with high rates of dark respiration relative to Pmax the rates of 'light' respiration were closer to rates of dark respiration. In the Synechococcus clone, both gross and net oxygen production rates were inhibited at high light intensities. Rates of 'light' respiration were found to vary as a function of light intensity. The greatest rates of respiration were measured in samples incubated at light intensities that were just saturating (∼100 μE m −2 s −1 ). The rates of 14 C production were also measured as a function of light intensity The photosynthetic quotients, based on 14 C production rates and gross oxygen production rates, average ∼1 9

In this study, to explore the influence of metals and oxides on the oxygen production rate and stability of sodium chlorate oxygen candles, 28 experimental samples were investigated. The effects of Co2O3, Co3O4, and Fe2O3 with different mass fractions on the thermal decomposition temperature and thermal decomposition rate of sodium chlorate were compared and analyzed. Co3O4 (5%) was obtained to reduce the thermal decomposition range to 260–450°C and reduce the pyrolysis interval ∆T to 46.2°C. Through the development of three metals (Fe, Mg, and Mn), under four mass fractions (2%, 4%, 6%, and 8%) mixed with Co3O4 (5%), the results of the effective oxygen production efficiency test for the thermal decomposition reaction of sodium chlorate demonstrated that Mn (6%)–Co3O4 (5%) exhibited the best catalytic and heat coupling effect; the effective oxygen production efficiency of 97.8% was achieved. Oxygen candle oxygen supply experiment was conducted; the oxygen candle composition for the test was determined to be NaClO3 (86%), Mn (6%), Co3O4 (5%), and kaolin (3%); in the four stages of the oxygen candle oxygen supply reaction test, the average oxygen supply rate reached 1.647 L/min, actual oxygen production was 28 L, and effective oxygen production rate of the oxygen candle was 53.6%. An increase of 9% was observed compared to the previous similar studies. The results of this study present a formula to optimize the oxygen supply of the oxygen candle, which is crucial for improving the oxygen supply performance of the oxygen candle.

To investigate the dispersion process of the underground toxic gas carbon monoxide (CO) into the refuge chamber during a mine disaster and enhance the survival rate of trapped miners, a simplified model of an underground refuge chamber and the main roadway was constructed. The impact of temperature and pressurized air volume on CO dispersion into the refuge chamber has been examined through both analog experiments and numerical simulations, and the reliability of the simulation results was verified. The results indicate that CO dispersion into the refuge chamber through the top of the protective isolation door occurs when the temperature in the refuge chamber is lower than that of the toxic gas. When the temperature of the toxic gas is higher, it tends to enter the refuge chamber through the bottom of the protective isolation door. The evolution of CO concentration in the transition chamber can be divided toxic survival chamber can be categorized into a sudden decline stage and a stable stage. And a flexible isolation door designed to control the entry of toxic gases into the refuge chamber was implemented, and its impact on CO dispersion has been compared and analyzed. When the temperature of the main roadway is 50 °C and the temperature of the refuge chamber is 20 °C, the required pressurized air volume to maintain the CO concentration within the safe threshold (24 ppm) is reduced to 69.6% of that needed without the isolation door, thereby significantly reducing the infiltration of harmful gases from the main roadway into the refuge chamber.

Выполнены измерения чистого экосистемного обмена (NEE) на мочажинном участке грядовомочажинного комплекса олиготрофного болота «Мухрино» с разделением на составляющие компоненты: валовую первичную продукцию (GPP) и дыхание экосистемы (R eco ). Измерения проводились в течение самого тёплого (июль), переходного (сентябрь) и самого холодного (октябрь) месяцев летне-осеннего сезона методом автоматизированных камер с 30-минутным интервалом. Это позволило получить подробную информацию о суточном ходе и сезонной динамике показателей. Для исследованных месяцев по отдельности и полевого сезона в целом осуществлен корреляционный анализ связи между гидрометеорологическими параметрами и величиной потоков. Для дыхания экосистемы (R eco ) наиболее высокий уровень корреляции за сезон выявлен с температурой почвы (0.88), температурой воздуха (0.71) и уровнем болотных вод (-0.73); за июль наиболее сильная корреляция выявлена с температурой воздуха (0.70) и температурой почвы (0.68); за сентябрь -с температурой почвы (0.81) и уровнем болотных вод (-0.78); за октябрь -с фотосинтетически активной радиацией (-0.59). Валовая первичная продукция (GPP) сильнее всего коррелирует с фотосинтетически активной радиацией (PAR) -в июле коэффициент корреляции равен -0.95, в сентябре -0.86, в октябре -0.79, в целом за полевой сезон -0.89. Чистый экосистемный обмен (PAR), аналогично GPP, наиболее тесно связан с PAR. В июле коэффициент корреляции NEE и PAR составляет -0.91, в сентябре -0.74, в октябре -0.71, за весь полевой сезон -0.73. Стоит подчеркнуть, что для каждого рассматриваемого месяца влияние внешних факторов на потоки уменьшается с течением времени от июля к октябрю, достигая минимума корреляции в самом холодном месяце. Ключевые слова: Дыхание экосистемы (R eco ); валовая первичная продукция (GPP); чистый экосистемный обмен (NEE); фотосинтетически активная радиация (PAR); LI-8100A; уровень грунтовых вод (WTL); автоматические камеры; Мухрино; болотные экосистемы Западной Сибири; круговорот углерода. Global climate change is one of the most important and promising phenomena to study in actual time. One of the key causes of global climate change is increasing the greenhouse gas (GHG) concentrations in the atmosphere [IPCC, 2023]. The main greenhouse gases are methane, carbon dioxides and nitric oxide, which contribute to the greenhouse effect and global warming [Lashof, Ahuja, 1990] . Carbon dioxide (CO 2 ) is one of the most significant and widespread gases involved in the planet's global carbon cycle [Lashof, Ahuja. 1990] . At the same time, living organisms play a key role in creation of atmosphere composition. Autotrophic organisms use a carbon dioxide to build their body structures, including complex organic compounds. During ecosystem functioning, the part of the carbon dioxide is released into the atmosphere through organism respiration, while another part is released through the decomposition of dead organic matter. Carbon dioxide may also be produced through natural and anthropogenic processes. Peatland ecosystems play a significant role in the planet's carbon cycle, both locally and globally. Peatlands in their natural undisturbed state are a significant long-term carbon sink 1 . However, the process of carbon deposition is not constantin different years, peatlands may serve either as carbon sink or source 2 . The main factor stimulating the carbon sequestration by peatland ecosystems is climatic conditions [Harenda et al., 2018; Bond-Lamberty et al., 2018] . Peatlands are the second most significant carbon stock on Earth and the largest on land. Despite covering only 2.84% of the Earth's land surface, the amount of soil organic carbon stored in them accounts for about one-third of all soil organic carbon on Earth. Peatlands in the northern hemisphere play a particularly important role in carbon sequestration, with an estimated accumulated carbon quantity of ~473-621 Gt of carbon [Yu et al., 2010] . The largest area of peatlands in Russia is located in Western Siberia, estimated at ~42% of the total Russian area [Vomperskiy et al., 1994; Sheng et al., 2004]. The territory of Western Siberia is featured to a high share of peatlands in original undisturbed state, making them an ideal location to study the impact of global changes on peatland biogeochemical functioning worldwide. The carbon balance of peatlands is mainly determined by two processes: photosynthesis and respiration [Harenda et al., 2018] . The main factors influencing the CO 2 flux from peatlands are photosynthetically active radiation, atmospheric air temperature (T avg ), soil temperature (T soil ), and water table level (WTL) [Miao et al., 2013;

(1) Potamogeton crispus L. is common in lakes ('pans') on the floodplain of the Pongolo river in South Africa. The pans are flushed by the river during summer but isolated during the winter. Growth of Potamogeton was found to be markedly seasonal, starting in autumn (April) and reaching maximum above-substrate standing crop (43 g m-2) in early spring (September). No plants were present during summer. (2) Sixty percent of the 1129 m-2 of the vegetative buds (turions) on the sediment surface in April germinated. Although seed density was high (1445 m-2), only 0.001% germinated during the study period. (3) Under experimental conditions, turion germination was significantly inhibited at a temperature of 25 'C and above. In the field, turions germinated only in autumn, when the water temperature had dropped below 25 'C. (4) Individual plants have a short life (c. 5 months), but because turion germination occurs over a period of about 3 months, and newly-produced turions do not germinate until the following year, the population persists for 8-9 months each year. (5) Leaf chlorophyll concentration and the rate of oxygen production by shoot tips declined during spring, but plants that developed late in the season, and which were present during early summer, had a high rate of shoot-tip oxygen production. It is suggested that the decline in standing crop is not caused by high summer temperature. (6) The factors initiating turion development on the mature plant are not clear. Turion production accounted for 23% of the maximum standing crop. (7) Both development and decline of the standing crop had a marked effect on the nutrient dynamics of the pan. Nitrogen appeared to be the nutrient in least supply during growth, and may have been limiting. The disappearance of P. crispus in spring was associated with a release of nutrients into the water at a rate which exceeded uptake by other components of the system. These nutrients may be flushed from the pan during the summer floods.

To the Editor: Three cases of carbon dioxide rebreathing without a significant color change in the appearance of the canisters were experienced during general anesthesia with the same model anesthesia machines; Aestiva/5 (Datex Ohmeda, Wisconsin, USA) with a fresh gas flow of 1–2 l/min. Carbon dioxide rebreathing was recognized because the inspiratory carbon dioxide baseline of the capnogram trace gradually rose. The inhalational carbon dioxide concentration decreased immediately after increasing the fresh gas flow, and rose again with decreasing the fresh gas flow. This indicates that carbon dioxide rebreathing was due to carbon dioxide accumulation in the semi-closed circuit system of the anesthesia machines. A color change in the appearance of the carbon dioxide absorbent was recognized only in the upper part of the canister (Fig. 1a). The top surface of the canister showed a significant color change limited to the middle part of it (Fig. 1b). The section image of the canister showed a significant columnar color change of the carbon dioxide absorbent along the full length of the center part of it (Fig. 1c). The observation of the canister bottom of Aestiva/5 revealed that only the center part of it had the mesh part for the exhaled gas, and the color change of the carbon dioxide absorbent seemed to accord with the mesh part of the bottom (Fig. 1d). As an experiment, when a transparent plastic partition wall was settled in the canister before filling with carbon dioxide absorbent, the columnar color change was no longer visible. This indicated that the flow of the exhaled gas was influenced by the wall in the canister. Considering these results, it is supposed that the structural characteristic of the canister bottom of the anesthesia machine; Aestiva/5, caused channeling and the inhomogeneity of the current of inhaled gas in the canister led to the columnar color change of the carbon dioxide absorbent. The role of the carbon dioxide absorbent canister becomes more important as the fresh gas flow quantity decreases. A technique of using a fresh gas flow of 1 l/min was reported first in 1952 [1]. The technique with the fresh gas flow less than 1 l/min subsequently became known as ‘‘low-flow anesthesia’’. Afterwards, a technique using a fresh gas flow of 500 ml/min was reported as ‘‘minimal flow anesthesia’’ [2]. These cases of carbon dioxide rebreathing without significant color change in the appearance of the canisters provide very important information not only for anesthesiologists, but also for all persons using anesthesia machines. When carbon dioxide rebreathing is recognized, carbon dioxide accumulation in the circuit system of the anesthesia machines should be suspected and exhaustion of the carbon dioxide absorbent should be immediately T. Yamamoto (&) Department of Pediatric Anesthesiology and Critical Care Medicine, Children’s Hospital Asklepios Klinik Sankt Augustin, Arnold-Janssen-Str. 29, 53757 Sankt Augustin, Germany e-mail: yamatomo270@hotmail.com; t.yamamoto@asklepios.com

ABSTRACT: This study aims to determine the potential of biomass, carbon stocks, and carbon dioxide (CO2) absorption in forest stands in the Abdul Latief Forest Park, Sinjai District, South Sulawesi Province. Measurement of biomass at various levels of growth was carried out by making plots of 20 with a size of 20 m x 20 m for tree level, 10 m x 10 m for pole level and 5 m x 5 m for sapling level. Tree biomass, poles and saplings are calculated using allometric equations for tropical wood species in Indonesia. Measuring carbon stocks is done by multiplying biomass with a conversion rate of 0.47 (47%) while carbon dioxide (CO2) absorption is calculated by multiplying the average annual growth of biomass with a conversion rate of 1.4667 obtained from the photosynthesis equation. Based on the results of the study showed that the biomass content of forest stands in the Abdul Latief Forest Park was 192.10 Ton/Ha, carbon stocks in the forest stand in the Abdul Latief Forest Park were 90.28 Ton/Ha, the oxygen production was 385,59 Ton/Ha and the absorption of carbon dioxide (CO2) in forest stands in Abdul Latief Forest Park of 13.13 Tons/Ha/Year oksigen. Value of Environmental services carbon dioxide was Rp. 35.267.664/Ton/Tahun Keywords : Biomass, Carbon dioxide absoption, Oxygen Production, Value of Enviromental Services, Forest Park

In the development of life support systems for long-term space missions, the most important tasks are the absorption of carbon dioxide from the air, the production of carbon dioxide with a concentration above 98 %, and the production of oxygen from carbon dioxide by the Bosch – Sabatier process. To solve these problems, a regenerative carbon dioxide absorber adapted to space flight conditions is required. The article proposes a new method for the production of chemosorbents based on hydrated zirconium oxide using polyacrylates as a binder and polymer matrix. The regenerated absorber of carbon dioxide for its application in space flights must meet the regulatory requirements of sanitary-chemical and toxicological safety of materials intended for the equipment of inhabited sealed rooms, be resistant to radiation and to the effects of mold. In the study of the processes of “sorption – desorption” of carbon dioxide, we have established the relationship between the technological parameters of the synthesis of chemosorbents and the kinetic parameters of the processes of mass-sorption of sorbate in the “sorption – regeneration” cycles. It is found that the optimal weight ratio of the “adsorbent – filler/polymer matrix” 89÷94/11÷6 is optimal in terms of the performance characteristics of the developed absorbers. It is shown experimentally that the main operational characteristics of the developed materials do not change under experimental conditions during 2000 “sorption – regeneration” cycles. The resulting chemosorbents are investigated by physicochemical analysis. Employing methods of gas chromatography and chromatomass spectrometry, we have conducted sanitary and chemical studies and toxicological assessment of the quantitative and qualitative composition of the components of gas release of the developed regenerated carbon dioxide absorber and air-gas mixture formed during the regeneration of the regenerated carbon dioxide absorber. Also we have carried out microbiological tests of samples of the regenerated absorber of carbon dioxide for resistance of material to influence of mold mushrooms. The results obtained confirm the possibility of using the developed materials in life support systems of manned spacecraft for deep space exploration.

Second wave of COVID-19 pandemic and the surge of mucormycosis: Lessons learnt and future preparedness: Indian Society of Anaesthesiologists (ISA National) Advisory and Position Statement.

To clarify the oxygen budget in the bottom layer of the southwestern part of Suo-Nada, we measured the oxygen consumption and production rates of the bottom sea water, sinking particles and bottom sediment in laboratory conditions from July to August, 1995. Then we also measured the contents of organic carbon, chlorophyll a and pheo-pigments in these substances. The mean total oxygen consumption rate in the bottom layer was 2.85g O2/m2/day; ca. 72% was caused by the bottom sea water, ca. 26% by the bottom sediment and ca. 2% by the sinking particles. On the other hand, the mean total oxygen production rate was 1.40g O2/m2/day; ca. 98% was caused by the bottom sea water and ca. 2% by the sinking particles. These results suggest that the oxygen consumption rates and the oxygen production rates by the bottom sea water play important roles in the formation of the oxygen deficient water mass in this water.

为探明中国北方浅水湖泊乌梁素海冰封期水体溶解氧平衡的内在机理，于2021年1—2月在湖心处布设了一台水质在线监测浮标，收集到包括溶解氧等在内的水质数据. 通过对溶解氧数据的小波降噪处理，结合气象资料，模拟分析了冰生长及稳定期内水体溶解氧的变化趋势，定性分析了水体溶解氧的平衡机理. 结果表明：湖泊的日均最高产氧速率为7.19 mg/(L ·d)，最低产氧速率为2.01 mg/(L ·d); 日均最高耗氧速率为7.13 mg/(L ·d)，最低耗氧速率为2.37 mg/(L ·d). 24 h的单位时间平均最高产氧速率为0.55 mg/(L ·h)，最低产氧速率为0 mg/(L ·h); 单位时间平均最高耗氧速率为0.36 mg/(L ·h)，最低耗氧速率为0.08 mg/(L ·h). 由此说明小时间尺度下溶解氧的补充消耗不均衡导致了大时间尺度下的溶解氧不平衡，进而产生了冬季湖泊的亏氧现象. 通过进一步溶解氧驱动因素与水环境因子响应关系的分析发现，浊度、水温与产氧速率呈显著负相关，叶绿素a与产氧速率和耗氧速率均呈显著正相关，表明了这些限制性水环境因子在一定程度上影响了冰下水体的溶解氧平衡.;In order to probe into the internal mechanism of dissolved oxygen (DO) equilibrium in the shallow Lake Wuliangsuhai in Northern China during the ice-covered period, a set of online water monitoring buoys were arranged in the center of lake for collection of water quality data from January to February, 2021. Upon the wavelet denoising processing of DO and based on the meteorological data, the DO changes during the growth and stability period of ice was simulated and analyzed, followed by a qualitative analysis of the mechanism of the DO equilibrium. Results show as follow: The lake's maximum daily average oxygen production rate was 7.19 mg/(L ·d); the minimum was 2.01 mg/(L ·d). The maximum daily oxygen consumption rate was 7.13 mg/(L ·d) and the minimum was 2.37 mg/(L ·d). The maximum 24-hour per-unit-time average oxygen production rate was 0.55 mg/(L ·h) and the minimum was 0 mg/(L ·d). The maximum per-unit-time average oxygen consumption rate was 0.36 mg/(L ·h) and the minimum was 0.08 mg/(L ·h). This study indicates that the disequilibrium between the DO production and consumption on small time scales results in DO disequilibrium on large time scales, causing oxygen deficiency in the lake in winter. Further analysis on the relationship between DO driving factors and water environment factors suggests a negative correlation between turbidity, water temperature and oxygen production rate and a positive correlation between chlorophyll-a and oxygen production and consumption rate, which indicates that these restrictive water environmental factors influence the DO equilibrium in water body under ice.

Background: There is paucity of data globally regarding availability of essential medical products and oxygen supply in healthcare facilities to inform surge capacity and strategic healthcare development. Due to continued waves of COVID-19 pandemic caused by virus variants with increased transmissibility, many facilities worldwide, particularly in the Indian subcontinent, have reported sudden increase in demand for oxygen and its delivery systems to treat patients with COVID pneumonia. Therefore, we aimed to assess the status of essential medical products, oxygen supply, and methods of procurement in COVID-19 treatment facilities across Nepal. Methods: We performed cross-sectional survey among 120 COVID-19 treatment facilities designated by the Government of Nepal in June 2020. Data were collected via an online semi-structured questionnaire based on validated healthcare capacity assessments. responded (49 clinics, 20 level hospitals). Findings: Sixty-nine facilities responded (49 clinics, 20 hospitals). All 69 facilities reported at least one form of oxygen availability: 25 facilities (36%) had their own oxygen plant, 65% had oxygen concentrators, and 88% had portable oxygen cylinders. Majority (38/49; 77%) of clinics and 60% (12/20) of hospitals had sufficient stock (³5 pieces in clinics, >20 pieces in hospitals) of functional oxygen cylinders, which were generally procured through the private sector (78% of facilities with oxygen cylinders). Almost all clinics had at least one piece of pulse oximeter device, blood pressure measuring set, thermometer, thermal gun, and resuscitation kit (oral or nasal airway, suction), compared to approximately a half of hospitals which had sufficient quantity (>10 pieces) of these products. Interpretation: It is crucial for hard-hit countries to timely map the availability and usage of essential medical products including oxygen in COVID-19 care hospitals. If needed, relevant policies and processes around oxygen production and supply should be revised. Furthermore, countries should not delay in adopting innovation for quicker, safer and sustainable production of medical oxygen to ensure continuous supply to the needy. Funding Information: No funding was received to conduct this study.Declaration of Interests: We declare no competing interests.Ethics Approval Statement: The study was approved by the Ethical Review Board (ERB) of Nepal Health Research Council ((Ref: NHRC-ERB Reg. No. 267/2020P), and utilizes specific data collected from a larger study done “to assess the service availability and infection prevention status of hospitals in Nepal in the context of possible COVID-19 case management need”.

Background: There is paucity of data globally regarding availability of essential medical products and oxygen supply in healthcare facilities to inform surge capacity and strategic healthcare development. Due to continued waves of COVID-19 pandemic caused by virus variants with increased transmissibility, many facilities worldwide, particularly in the Indian subcontinent, have reported sudden increase in demand for oxygen and its delivery systems to treat patients with COVID pneumonia. Therefore, we aimed to assess the status of essential medical products, oxygen supply, and methods of procurement in COVID-19 treatment facilities across Nepal. Methods: We performed cross-sectional survey among 120 COVID-19 treatment facilities designated by the Government of Nepal in June 2020. Data were collected via an online semi-structured questionnaire based on validated healthcare capacity assessments. responded (49 clinics, 20 level hospitals). Findings: Sixty-nine facilities responded (49 clinics, 20 hospitals). All 69 facilities reported at least one form of oxygen availability: 25 facilities (36%) had their own oxygen plant, 65% had oxygen concentrators, and 88% had portable oxygen cylinders. Majority (38/49; 77%) of clinics and 60% (12/20) of hospitals had sufficient stock (³5 pieces in clinics, >20 pieces in hospitals) of functional oxygen cylinders, which were generally procured through the private sector (78% of facilities with oxygen cylinders). Almost all clinics had at least one piece of pulse oximeter device, blood pressure measuring set, thermometer, thermal gun, and resuscitation kit (oral or nasal airway, suction), compared to approximately a half of hospitals which had sufficient quantity (>10 pieces) of these products. Interpretation: It is crucial for hard-hit countries to timely map the availability and usage of essential medical products including oxygen in COVID-19 care hospitals. If needed, relevant policies and processes around oxygen production and supply should be revised. Furthermore, countries should not delay in adopting innovation for quicker, safer and sustainable production of medical oxygen to ensure continuous supply to the needy. Funding Information: No funding was received to conduct this study. Declaration of Interests: We declare no competing interests. Ethics Approval Statement: The study was approved by the Ethical Review Board (ERB) of Nepal Health Research Council ((Ref: NHRC-ERB Reg. No. 267/2020P), and utilizes specific data collected from a larger study done “to assess the service availability and infection prevention status of hospitals in Nepal in the context of possible COVID-19 case management need”.