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Alkaline water electrolysis becomes increasingly important for the supply of renewable energy, and of raw material for the chemical industry. An attractive choice for the encapsulation of the electrolyte cell is an (advanced) engineering polymer. The objective of this paper is to find a suitable one that can withstand for many years: 30 wt% KOH solution and pure oxygen at a high pressure of 50 bar and at an elevated temperature of 90°C. Using CES EduPack, 12 possible thermoplastic polymers were selected, of which polyphenylene sulfide (PPS) and polysulfone (PSU) were further investigated using accelerated testing. The polymers have been exposed to three KOH concentrations (15, 30 and 45 wt%), two oxygen pressures (pure O2 at 5 bar and air with pO2 = 20%), and three temperatures (90°C, 120°C, and 170°C). Extensive characterization of the exposed samples has been carried out using various techniques, including weight, tensile, DMA, and creep-recovery measurements, as well as DSC, FTIR, XRD and SEM. After 12 weeks of aging, glass fiber reinforced PPS failed in a strong alkaline solution at high temperatures, due to the dissolution of the glass fibers. The PPS matrix itself and PSU turned out to be resistant to thermo-oxidative and chemical degradation under the conditions tested. Only marginal changes in mechanical, visco-elastic and thermal behavior were observed, which can be ascribed to physical rather than chemical aging. In view of the brittle nature of PPS, it could be concluded that PSU is the most promising candidate for the long-term application in alkaline electrolysis. Extrapolating the data using time-temperature superposition, it is predicted that PSU will retain its integrity and mechanical properties for a period of 20 years of operation.

The energy consumption for aquaculture in Vietnam, especially shrimp farming industry, has continued rising considerably in recent years due to the expand of shrimp production to meet food demand. Most of energy demand at shrimp farms is consumed by aeration system which uses electric motors to drive aerators for improving dissolved oxygen in ponds. In addition, the intensive energy consumption from electric motors for aeration and pumping systems leads to high operation cost and associated greenhouse gas emissions. Although many improvements have been done for the design and operation of aerators and even renewable energy resources have been applied, mechanical aerators still consume high power with low oxygen transfer from air. Therefore, this paper proposes an optimal design for advanced aeration system in which the electrolyzer powered by renewable energy might produce onsite pure oxygen according to the changes of dissolved oxygen level in shrimp ponds. The optimal results obtained from the elitist genetic optimization algorithm with life cycle cost and CO2 emission as objective functions conducted in off-grid and on-grid modes are compared with mechanical aeration system powered by national grid. The comparison in terms of life cycle cost and CO2 emission results that the hybrid system supplied by wind and photovoltaic power with national grid as backup represents the best configuration for the investigated shrimp farm because it not only provides better competitiveness for life cycle cost and low gas emission but also procures revenue at the end of the project lifetime.

Hyperbaric oxygen therapy involves inhaling pure oxygen in a pressurized room or tube. According to mayo clinic, Hyperbaric oxygen therapy is a well-established treatment for decompression sickness, a hazard of scuba diving. Other conditions treated with hyperbaric oxygen therapy include serious infections, bubbles of air in your blood vessels, and wounds that won't heal as a result of diabetes or radiation injury. A questionnaire composed of 10 structured questions with multiple choices were distributed via an online survey platform - Survey Planet. Total of 100 responses were recorded and analysed. The results obtained were tabulated and represented in the form of graphs. Most of them are aware about hyperbaric oxygen therapy however, there are some who are still unclear about the concept and facts. [ABSTRACT FROM AUTHOR]

The study investigated the influences of pure H 2 and O 2 introduction, simulating gases produced from the electrokinetic-enhanced bioremediation (EK-Bio), on TCE degradation, and the dynamic changes of the indigenous microbial communities. The dissolved hydrogen (DH) and oxygen (DO) concentrations ranged from 0.2 to 0.7 mg/L and 2.6 to 6.6 mg/L, respectively. The biological analysis was conducted by 16S rRNA sequencing and functional gene analyses. The results showed that the H 2 introduction enhanced TCE degradation, causing a 90.4% TCE removal in the first 4 weeks, and 131.1 μM was reduced eventually. Accordingly, cis -dichloroethylene (cis -DCE) was produced as the only product. The following three ways should be responsible for this promoted TCE degradation. Firstly, the high DH rapidly reduced the oxidation-reduction potential (ORP) value to around −500 mV, beneficial to TCE microbial dechlorination. Secondly, the high DH significantly changed the community and promoted the enrichment of TCE anaerobic dechlorinators, such as Sulfuricurvum , Sulfurospirillum , Shewanella, Geobacter, and Desulfitobacterium , and increased the abundance of dechlorination gene pceA. Thirdly, the high DH promoted preferential TCE dechlorination and subsequent sulfate reduction. However, TCE bio-remediation did not occur in a high DO environment due to the reduced aerobic function or lack of functional bacteria or co-metabolic substrate. The competitive dissolved organic carbon (DOC) consumption and unfriendly microbe-microbe interactions also interpreted the non-degradation of TCE in the high DO environment. These results provided evidence for the mechanism of EK-Bio. Providing anaerobic obligate dechlorinators, and aerobic metabolic bacteria around the electrochemical cathodes and anodes, respectively, or co-metabolic substrates to the anode can be feasible methods to promote remediation of TCE-contaminated shallow aquifer under EK-Bio technology. [Display omitted] • High DH enhanced TCE biodegradation, but high DO did not. • High DH enriched TCE dechlorinators and promoted them as keystones in the network. • High DH promoted preferential TCE dechlorination and subsequent sulfate reduction. • High DO showed unfriendly microbial interactions among TCE metabolizers and others. • Supplying functional microbes is proposed to enhance EK-Bio efficiency. [ABSTRACT FROM AUTHOR]

Waterless transportation is a novel method used to keep turbot alive during transportation. In the present study, the effect of atmospheric air or pure oxygen at low temperature on the morphology and several biochemical parameters of living turbot (Psetta maxima) subjected to water-free storage conditions were evaluated. The results of hematoxylin-eosin (HE) staining and scanning electron micrographs indicated that treatment of turbot with pure oxygen for 6 h had no effect on gill silk morphology, and slight shrinkage of the fish gill silks and deformation of the gill filaments were observed 12 h later, relative to the controls (living in the water). In contrast, the atmospheric air treatment induced dramatic alterations in gill structure with a wrinkled surface and narrowed space between gill filaments of the turbot. Furthermore, other biochemical indicators, including of ATP levels, blood glucose levels, cortisol levels and blood urea nitrogen levels, were similarly non-affected by the oxygen treatment, over the course of a 12 h treatment. The data of this study is helpful in understanding fish survival and in providing the theoretical base for improving the live transportation of turbot. • An analysis of turbot in response to waterless storage was investigated. • Glucose, ATP, cortisol, and BUN were stimulated by waterless storage. • Gill structure of Turbot were changed during waterless preservation at different oxygen levels. • Structure parameters of the gill lamellae were changed during waterless preservation at different oxygen levels. [ABSTRACT FROM AUTHOR]

In summer time when the temperature is high in greenhouse and the water's oxygen transport capacity is low, oxygen deficiency problem could be encountered due to high root and microorganism respiration rate, inadequate and frequent water application. Oxygen enrichment of nutrient solution may have an important role in terms of plant growing in order to solve this problem. In the present study, it was aimed to determine the effects of oxygen enrichment (oxyfertigation) of the tomato nutrient solution with 2 different oxygen sources (pure oxygen with a pressurized oxygen tube and aeration with compressor) on plant growth, yield, fruit quality, water and nutrient use. The data obtained from autumn and spring periods showed that the application of oxyfertigation increased the root biomass in particular and did not cause any significant difference on other measured parameters. Yield, quality, plant growth, water consumption, nutrient content were affected by the growing periods, and the parameters in question were higher in spring. It was concluded that among the evaluated oxygen sources -, aeration with compressor giving air bubbles to the nutrient solution could be a preferable application since it is economical and more practical than pure oxygen application with oxygen tube. [ABSTRACT FROM AUTHOR]

Pressurized steam electrolysis enables an efficient conversion of electric power from renewable energy sources into hydrogen for power-to-liquids processes. The interconnector material Crofer 22 APU, uncoated and coated by LaSrMnO (LSM), deposited by thermal spray and by roll coating was studied in pure water vapor and pure oxygen at 850 °C and 30 bar. The uncoated Crofer 22 APU forms in both atmospheres a homogeneous oxide scale from an inner CrO and an outer MnCrO layer. The chromia is locally undergrown by pits of MnCrO. With the LSM coating, the oxide scale is notably thinner in water vapor and the formation of pits is significantly reduced. In oxygen, this effect of the LSM coating is less pronounced. Chromium from volatile species was detected in the LSM coating, more in oxygen than in water vapor. After 3000 h in pure oxygen, Crofer 22 APU with thermally sprayed LSM shows breakaway oxidation. [ABSTRACT FROM AUTHOR]

Two data-driven models are presented to predict and analyze the performance of a PEM fuel cell operating on pure oxygen that can be used as an effective power source for air-independent operation of underwater vehicles, spacecrafts, unmanned aerial vehicles, etc. Both artificial neural network (ANN) and support vector machine (SVM) were employed as modeling methods to construct the nonlinear empirical models for a 1.2-kW PEM fuel-cell stack operating on high-pressure pure hydrogen and oxygen in dead-end mode. A sufficient amount of data was collected from a full factorial design of test operations of the fuel-cell stack. The hyper-parameters of the ANN and SVM models were determined using a 10-fold cross-validation scheme. The ANN model was found to show excellent performance and outperform the SVM model in predicting the polarization curves of the stack under various operating conditions, with the root mean square errors of 1.8–2.9 mV and the mean absolute percentage errors of 0.16–0.27%. Consequently, the ANN model was used to analyze and discuss in detail the effects of the major operating variables, including the stack temperature, the reactant inlet pressures, and the relative humidity of the supplied oxygen, on the performance of the stack. [ABSTRACT FROM AUTHOR]

A numerical model including 29 reactions and 11 species is developed to investigate the spatial-temporal distributions of species and electric field in oxygen parallel-plate positive pulsed dielectric barrier discharge for ozone generation. Electron energy conservation equation is coupled to electron continuity equation, heavy species continuity equation and Poisson's equation. The spatial-temporal distributions of species and electric field are obtained at electron avalanche and during streamer propagation. The results show the dominant positive ion, negative ion and excited species are O 2 + , O 3 − and O 2 ( ∑ g + 1 ) , respectively. The average streamer propagation velocity is about 5.56 × 10 4 m/s. Overall electron density almost increases exponentially but with a violent oscillation in the vicinity of anode at electron avalanche. Electron density increases at first and then declines in the vicinity of anode and streamer channel during streamer propagation, and increases gradually in streamer head with the development of streamer, as well as reduces sharply to almost zero near cathode. Electron density almost remains constant in whole streamer channel at any one moment. Other species have a similar spatial-temporal distribution. [ABSTRACT FROM AUTHOR]

Postharvest pericarp browning is one of the main problems resulting in reduced shelf life of longan fruit. Experiments were conducted to examine the changes in concentrations of adenosine triphosphate (ATP), adenosine diphosphate (ADP) and adenosine monophosphate (AMP), energy charge levels and activities of polyphenol oxidase (PPO) and peroxidase (POD) in relation to pericarp browning of longan fruit. Fruit kept for 6 days in pure oxygen atmosphere at 28 C showed lower browning indices and higher ATP concentrations but lower AMP concentrations and higher respiratory rates, compared to those kept in air. While energy charge decreased during storage, the decrease was delayed markedly by exposure to pure oxygen. There was a lower energy charge in the browned fruit, which was associated with rapid increase in malondialdehyde concentration. Enhanced respiration of longan fruit exposed to pure oxygen can result in the production of ATP. However, fruit exposed to pure oxygen exhibited higher activities of PPO and POD, which was not associated with reduced skin browning inhibition. These results supported the hypothesis that skin browning of postharvest longan fruit may be a consequence of membrane injury caused by the lack of maintenance energy.

A novel aerator for enhancing the oxygen transfer rate and efficiency, named multistage vortex aerator (MVA), was developed. It uses vortex flow in repeated stages to increase the gas-liquid interfacial area and to decrease the thickness of the stagnant layer at the interface between the two phases. The basic characteristics of oxygen transfer using this aerator were investigated using the American Society of Civil Engineers standard procedure. The MVA could rapidly transfer oxygen to water to a concentration higher than 40 mg/L in 60 min owing to the effect of high purity oxygen, additional pressure induced by water and gas, and vortex flow dynamics. A gas transfer model was developed for describing the non-steady state operation of the aerator. This model is based on the mass and molar balances of oxygen in gas and water. It could successfully simulate the DO change inside the aerator. This study can help better understand the oxygen transfer mechanism and evaluate the performance of the new aerator at the various temperatures, pressures, and gas compositions found in diverse environmental systems. [Display omitted] • We present an aerator that uses vortex flow and oxygen to enhance oxygen transfer. • The DO concentration exceeded 40 mg/L in 60 min at Q o2 3.0 L/min, T = 24 °C. • Standard oxygen transfer efficiency exceeded 50% without any tall tower. • Gas transfer model based on oxygen mass/molar balances in gas and water is provided. • The model is able to simulate performance of the aerator in diverse conditions. [ABSTRACT FROM AUTHOR]

The use of membrane bioreactors (MBRs) in activated sludge wastewater treatment has grown significantly in the last decade. While there is growing awareness and knowledge about the application of MBR technology in municipal wastewater treatment, not much information is available on the application of MBRs in industrial wastewater treatment. A comparative study of design data, operating conditions and the major challenges associated with MBR operations in 24 MBR plants treating both municipal and industrial wastewater, built by and/or operated by Praxair, Inc., is presented. Of the 24 MBR systems described, 12 of the plants used high purity oxygen (HPO). By enabling a wide range of food/microorganism ratios and loading conditions in the same system, HPO MBR systems can extend the options available to industrial plant operators to meet the challenges of wide fluctuations in organic loading and footprint limitations. While fouling in industrial MBR systems can be an issue, adequate flux and permeability values can be reliably maintained by the use of good maintenance strategies and effective process controls (pretreatment, cleaning and membrane autopsies). [ABSTRACT FROM AUTHOR]

In situ measurement of temperature distribution in a Proton Exchange Membrane Fuel Cell (PEMFC) stack is conducted by embed 36 T-type thermocouples on the MEA surface in four representative cells. Temperature increasing rate can get to 2.5°Cmin−1 at 1000mAcm−2. The largest temperature difference is observed in the middle of the stack, and the temperature difference can reach 17°C at the bottom of the stack. The non-uniformity of temperature distribution is found to be improved by increasing the operation pressure, and the largest temperature difference decreases by 2.5°C when the absolute operation pressure is increasing from 100kPa to 150kPa. [ABSTRACT FROM AUTHOR]

Performance of a bench-scale wastewater treatment plant, which consisted of a membrane bioreactor, was monitored daily using pure oxygen and air to supply aerobic conditions with the aim of studying the increases of the aeration and sludge removal efficiencies and the effect of the temperature. The results showed the capacity of membrane bioreactor systems for removing organic matter. The alpha-factors of the aeration were determined for six different MLSS concentrations in order to understand the system working when pure oxygen and air were used to supply aerobic conditions in the system. Aeration efficiency was increased between 30.7 and 45.9% when pure oxygen was used in the operation conditions (a hydraulic retention time of 12 h and MLSS concentrations between 4,018 and 11,192 mg/L). Sludge removal efficiency increased incrementally, from 0.2 to 1.5% when pure oxygen was used at low sludge retention time and from 1.5% to 15.4% at medium sludge retention time when temperature conditions were lower than 20°C. Moreover, the difference between calculated and experimental sludge retention time was lesser when pure oxygen was used to provide aerobic conditions, so the influence of the temperature decreased when the pure oxygen was used. These results showed the convenience of using pure oxygen due to the improvement in the performance of the system. [ABSTRACT FROM AUTHOR]

A comparative analysis was performed in a pilot-scale membrane bioreactor (MBR) treating urban wastewater supplied with either pure oxygen (O2) or air, to assess the influence of each aeration source on the diversity and activity of the bacterial communities in the sludge. The MBR was operated in three experimental stages with different concentrations of volatile suspended solids (VSS) and temperature, and under both aeration conditions. α-Glucosidases, proteases, esterases and phosphatases were tested as markers of organic matter removal in the sludge, and the diversity of the bacterial community was analysed by fingerprinting (temperature-gradient gel electrophoresis of partially-amplified 16S-rRNA genes). Redundancy analysis (RDA) revealed that temperature and VSS concentration were the only factors that significantly influenced the levels of enzyme activities and the values of both the Shannon–Wiener diversity index (H′) and the functional organisation index (Fo), while the bacterial community structure experienced significant changes depending on the aeration source supplied in each experimental stage. [Copyright &y& Elsevier]

The purification of different components of air, such as oxygen, nitrogen, and argon, is an important industrial process. Pressure swing adsorption (PSA) is surpassing the traditional cryogenic distillation for many air separation applications, because of its lower energy consumption. Unfortunately, the oxygen product purity in an industrial PSA process is typically limited to 95% due to the presence of argon which always shows the same adsorption equilibrium properties as oxygen on most molecular sieves. Recent work investigating the adsorption of nitrogen, oxygen and argon on the surface of silver-exchanged Engelhard Titanosilicate-10 (ETS-10), indicates that this molecular sieve is promising as an adsorbent capable of producing high-purity oxygen. High-purity oxygen (99.7+%) was generated using a bed of Ag-ETS-10 granules to separate air (78% N2, 21% O2, 1% Ar) at 25°C and 100 kPa, with an O2 recovery rate greater than 30%. © 2012 American Institute of Chemical Engineers AIChE J, 59: 982-987, 2013 [ABSTRACT FROM AUTHOR]

Abstract: A submerged MBR with a pure oxygen system was operated at high COD loading conditions to find out how high a level of COD loading can be treated consistently in an aerobic condition. Pure oxygen was supplied with circulated MLSS to the aerobic tank by a two-phase nozzle to increase oxygen transfer efficiency. Tested COD loadings ranged from 2 to 10kgCOD/m3 day. And the effect of MLSS concentration on the membrane fouling was investigated from 5000 to 25,000mg/L. The membrane fouling rates and filtration resistance were tested to evaluate the effect of COD loadings and MLSS concentrations. Over the range of COD loading tested (2.0–10kgCOD/m3 day), the effluent qualities ranged from 35 to 69mg/L and the COD removals ranged from 99.1 to 99.7 for synthetic wastewater. The membrane fouling rates increased seven-fold over a five-fold increase in COD loadings. And the fouling rates increased almost nine-fold over a three-fold increase in MLSS concentration. The membrane fouling in high COD loading conditions was more sensitive to MLSS concentration than COD loading. The specific EPS productions in this test ranged from 6.9 to 10.9mgEPS/gVSS, and the specific polysaccharide and protein productions were 9.2mgPolysaccharide/gVSS and 1.8mgProtein/gVSS, respectively. [Copyright &y& Elsevier]

Abstract: A MBR (membrane bioreactor) was performed to quantify the improvement in nitrogen removal terms when pure oxygen and air were used to supply the aerobic conditions at different HRT (hydraulic retention time) and mixed liquid suspended solids concentrations. The improvement in the efficiency was 8.0% and 13.5% when pure oxygen was used with 12h and 18h of HRT repectively. The ammonium utilization rates with HRT of 18h with pure oxygen was 1.23mgNt/(L h) and with air 0.66mgNt/(L h) and with HRT of 12h was 1.14mgNt/(L h) and 1.18mgNt/(L h) respectively. Model simulation (DESSAS software) confirmed the validity for nitrogen removal, hydrolysis constant was increased (106% and 184%), decay constant was decreased and Monod’s constant was increased (190.4% to 324.1%), and a multivariate analysis with CANOCO v4.5 demonstrated that temperature and HRT have the higher influence in kinetics. [Copyright &y& Elsevier]

Abstract: The performance of a wastewater bench-scale membrane bioreactor (MBR) treatment plant using pure oxygen conditions was monitored daily to provide aerobic conditions. The results showed the capacity of the MBR system to remove organic material over at hydraulic retention time (HRT) of 12h and 18h. The alpha-factors of aeration were determined at three different mixed liquid suspended solids (MLSS) concentrations, in order to understand the system performance when pure oxygen was used to provide the aerobic conditions of the MBR system. Under these working conditions, an alpha-factor in the range 0.90–0.12 was obtained when the HRT of 18h was performed, and the MLSS concentration increased from 4300 to 10,275mg/L. Additionally, an alpha-factor in the range of 0.28–0.02 was obtained at HRT of 12h and the MLSS increased from 4071 to 11,192mg/L. Our study suggested significant changes in the behaviour of the biological system (viscosity, aeration efficiency, organic matter removal) when the concentration of MLSS was increased and the HRT decreased in the bioreactor, decreasing the aeration efficiency in both cases. Furthermore, the efficiency of aeration seems to be more affected by MLSS concentration than by HRT under our operating conditions over the range studied. [Copyright &y& Elsevier]

Abstract: A pilot-scale membrane bioreactor was used to treat urban wastewater using pure oxygen instead of air as a source of aeration, to study its influence on bacterial diversity and levels of enzyme activities (acid and alkaline phosphatases, glucosidase, protease, and esterase) in the sludge. The experimental work was developed in two stages influenced by seasonal temperature. Operational parameters (temperature, pH, BOD5, COD, total and volatile suspended solids) were daily monitored, and enzyme activities measured twice a week. Redundancy analysis (RDA) was used to reveal relationships between the level of enzyme activities and the variation of operational parameters, demonstrating a significant effect of temperature and volatile suspended solids. Bacterial diversity was analyzed by temperature-gradient gel electrophoresis of PCR-amplified partial 16S rRNA genes. Significant differences in community structure were observed between both stages. Sequence analysis revealed that the prevalent Bacteria populations were evolutively close to Alphaproteobacteria (44%), Betaproteobacteria (25%) and Firmicutes (17%). [Copyright &y& Elsevier]

Sensory gating, a viable function of the brain, is an adaptive mechanism to prevent overstimulation of nervous system. The aim of this study was to examine the effect of homobaric pure (i.e. 100%) oxygen on the human brain at different periods of inhalation. EEG was recorded while an auditory paired-click sensory gating test was conducted during 4 study periods: before inhalation of pure oxygen (Before), inhalation of 100% oxygen (air in control group) for 20 min (Oxy20) and 50 min (Oxy50), 30 min after oxygen (air in control group) inhalation (After). Each of the auditory stimuli elicited 4 clear peaks at 20, 39, 55 and 100 ms in ERPs, demonstrating that sensory gating is a multi-stage process. Comparing the S1-S2 differences of field potentials between two groups, significant experimental effects ( P < 0.05-0.01) were shown at Oxy50 and After periods mainly at the 20 and 100 ms peak in ERPs. Pure oxygen was experimentally shown, for the first time, to affect the human brain activation, at the beginning of early P20 sensory cortical activation and late N100 auditory perception. The effect found in this study shall encourage further investigation on the oxygen treatment in human brain. [ABSTRACT FROM AUTHOR]

Abstract: The performance of a wastewater bench-scale ultrafiltration membrane bioreactor (MBR) treatment plant using pure oxygen to supply the aerobic conditions for 95days was studied. The results showed the capacity of the MBR systems to remove organic material under a hydraulic retention time of 12h and a sludge retention time of 39.91days. Aeration represents its major power input; this is why the alpha-factor of the aeration and kinetic parameters (design parameters) were determined when the mixed liquid suspended solids (MLSS) was increased from 3420 to 12,600mg/l in order to understand the system. An alpha-factor in the range 0.462–0.022 and the kinetic parameters measured with the respirometric method (K M of 73.954–3.647mg/l, k d of 0.0142–0.104day−1, k H of 0.1266–0.655day−1, and the yield mean coefficient of 0.941) were obtained. Our study suggested significant changes in the behaviour of the biological system when the concentration of MLSS was increased. [Copyright &y& Elsevier]

The article focuses on a study conducted by the authors on effect of intensity of turbulence on efficiency of oxygen transfer in membrane coupled pure oxygen high-performance compact reactor (MPHCR) for wastewater. It mentions that the process of MPHCR could be operated at high chemical oxygen demand (COD) due to high efficiency of oxygen transfer.

Pure oxygen to supply the aerobic condition was used in the performance of a bench-scale submerged membrane bioreactor (MBR). The pilot plant was located in the wastewater treatment plant of the city of Granada (Spain) and the experimental work was divided into two stages (Unsteady state and steady state conditions). Operation parameters (MLSS, MLVSS and dissolved oxygen concentration) and physical characteristics (temperature, conductivity, pH, COD and BOD5) were daily monitored. The results showed the capacity of the MBR systems to remove organic material under a hydraulic retention time of 18.46 h and sludge retention time of 18.6 days. Therefore, Viscosity of the sludge and α kL a-factor of the aeration, were determinate in the steady stage condition to understand the behavior of the system when pure oxygen has been used to supply the aerobic conditions of the MBR system showed an alpha-factor of 0.238 when the viscosity of the system was 4.04 Cp. [ABSTRACT FROM AUTHOR]

Pure oxygen is vital in medical treatment, first aid, and chemical synthesis. Hypoxia can cause severe damage to the organ systems such as respiratory, digestive, and nervous systems and even directly cause death. Notably, the severe Coronavirus disease 2019 (COVID-19) pandemic has exacerbated the shortage of medical oxygen in the world. Hence, a safe, economical, and portable oxygen supply device is urgently needed. Here, we have successfully prepared a device with air-breathing electrochemical extraction of pure oxygen (ABEEPO) with light weight and high energy efficiency. By renovating the structure of the electrolytic cell, the components bipolar plate and end plate are replaced with a plastic membrane, and the component current collector is replaced with a highly conductive graphene composite membrane electrode. Due to the use of the plastic membrane and graphene composite membrane electrode, the weight of the electrolytic cell is reduced from 1319.4 to 1.6 g, and the flexibility of the electrolytic cell is successfully realized. Through optimizing anode catalysts, working area, and operating voltage, a high flow rate per mass (234 mL h -1 g -1 ) was achieved at a voltage of 1.2 V. The device exhibits high stability in 2 h. The new portable oxygen production device would be effective for hypoxia treatment.

• A calculation method of coal spontaneous combustion period based on Arrhenius law. • Heat loss rate (RPD) function during coal spontaneous combustion was constructed. • Coal spontaneous combustion parameters obtained by pure O 2 adiabatic oxidation. • The pure O 2 adiabatic method can quickly obtain the spontaneous combustion period. Spontaneous combustion period is an important characteristic parameter of coal spontaneous combustion. It must be understood to prevent and control coal fire disasters in a coal mine. Fresh coal samples were then collected from the Bulianta Coal Mine in the Shenfu-Dongsheng Coalfield for mini combustion furnace experiments. We then analyzed the changing rules of coal temperature, O 2 and CO during spontaneous combustion of coal under pure oxygen adiabatic conditions. A method for calculating oxygen consumption rate during spontaneous combustion of coal under those conditions was then proposed. Based on the Arrhenius law, heat loss rate (RPD) function during coal spontaneous combustion was developed. The coal temperature and oxygen concentration during spontaneous combustion oxidation process of coal in air accurately were calculated from a pure oxygen insulation experiment. When RPD air = 0, 0.2, 0.4, 0.6, and 0.8, the coal spontaneous combustion periods of Bulianta were 15.12, 18.94, 25.25, 37.87, and 75.74 days, respectively. The spontaneous combustion period of Bulianta coal, which was measured using 2-t experimental furnace for coal spontaneous combustion, was 16.66 days. The temperature change curve for spontaneous ignition experiment is similar to the adiabatic condition (RPD air = 0). This demonstrates that the coal spontaneous combustion period calculation method in air using pure oxygen adiabatic experiment is valid. [ABSTRACT FROM AUTHOR]

In this study, a new aeration approach was used for cathode by offering an efficient and cost-effective alternative for practical applications of microbial fuel cells. Therefore, a new sandwich type microbial fuel cell was constructed having three chambers (two anodes and one cathode) was constructed. This sandwich type microbial fuel cell was fed with a mixture of sewage sludge and algae biomass (at the ratio of 1:1). The pure oxygen gas was delivered to the cathode by using hydrophobic hollow fiber gas transfer membranes at different gas pressures (2, 4, 6, 8 and 10 psi). The results revealed that this new sandwich type microbial fuel cell achieved a good performance, and the max power density increased from 1448 mW m−2 to 26680 mW m−2 with an increase in oxygen pressure from 2 psi to 10 psi. The presence of electrochemically active bacteria-colonization on the anode's surfaces was revealed by microscopic observations and molecular analysis. This study demonstrated the feasibility of using a hollow fiber gas transfer membrane and a mixture of sewage sludge and algae biomass to enhance power production by sandwich type microbial fuel cell. Image 1 • A new sandwich type MFC was constructed having three chamber. • Hollow fiber gas transfer membrane was used to provide effective cathode aeration. • This new approach can overcome the high operational cost of MFC. • The ratio of electrochemically active b-proteobacteria in the anode was 32%. • The max power density in the ST-MFC was reached 26680 mW m−2 at 10 psi. [ABSTRACT FROM AUTHOR]