Air Oxygen Research Articles

Medical Problems of Chronic Hypoxia in Highlanders Living on the Tibetan Plateau.

Ri-Li Ge. Medical problems of chronic hypoxia in highlanders living on the tibetan plateau. High Alt Med Biol. 00:00-00, 2024.-Health issues at high altitudes arise due to the lower atmospheric pressure and subsequent reduction in the partial pressure of oxygen in ambient air. While much research has been published on health problems of lowlanders who move to high altitudes, less is known about the medical challenges faced by long-term and permanent high-altitude residents, especially in the Qinghai-Tibetan plateau. In this review, we briefly summarized the chronic hypoxia-related health issues in highlanders, focusing on the specific population of the Qinghai-Tibetan plateau. It deals with important health problems for highlanders, including the main disease categories, from chronic mountain sicknesses and pulmonary hypertension (PH) to kidney, neurocognitive impairments, perinatal problems, and congenital heart defect. However, the most hallmark of disorders is excessive erythrocytosis associated with specific symptoms and signs, and high-altitude heart disease is characterized by excessive PH, right ventricular hypertrophy, and right heart failure. We also provide information on potential treatment strategies, including some traditional Tibetan medical practices and also a combination of Western medicine and traditional Chinese medicine to prevent and treat these conditions effectively. This mini-review is heavily based on a couple of decades of research carried out by Chinese high-altitude medical research groups at the Qinghai-Tibetan Plateau. We believe that this review will provide valuable perspective to researchers whose study interest and base lie in high altitude.

Highly Efficient Photocatalytic H2O2 Production under Ambient Conditions via Defective In2S3 Nanosheets.

Oxygen and water generating hydrogen peroxide (H2O2) by optical drive is an extremely promising pathway, and the large amount of oxygen in air and natural sunlight illumination are excellent catalytic conditions. However, the separation efficiency of photogenerated electron-hole pairs greatly limits the photocatalytic efficiency, especially in the absence of sacrificial agents. Here, we report an In2S3 nanosheet with an S vacancy (Sv-In2S3). The highest H2O2 yield of Sv-In2S3 is 2.585 mmol g-1 h-1 under pure water, air, and sunlight (P = 920 W/m2), largely outperforming other reported photocatalysts for H2O2 production. The experimental results show that the introduction of Sv accelerates the separation of photogenerated electron-hole pairs and achieves efficient H2O2 production through an oxygen reduction reaction. This efficient photosynthesis under ambient conditions allows solar-chemical conversion to take place in a truly cost-effective and sustainable way, opening up possibilities for practical production.

PEGylated ATP-Independent Luciferins for Noninvasive High-Sensitivity High-Speed Bioluminescence Imaging.

Bioluminescence imaging (BLI) is a powerful, noninvasive imaging method for animal studies. NanoLuc luciferase and its derivatives are attractive bioluminescent reporters recognized for their efficient photon production and ATP independence. However, utilizing them for animal imaging poses notable challenges. Low substrate solubility has been a prominent problem, limiting in vivo brightness, while the susceptibility of luciferins to auto-oxidation by molecular oxygen in air increases handling complexity and poses an obstacle to obtaining consistent results. To address these issues, we developed a range of caged PEGylated luciferins with increased auto-oxidation resistance and water solubility of up to 25 mM, resulting in substantial in vivo bioluminescence increases in mouse models. This advancement has created the brightest and most sensitive luciferase-luciferin combination, enabling high-speed video-rate imaging of freely moving mice with brain-expressed luciferase. These innovative substrates offer new possibilities for investigating a wide range of biological processes and are poised to become invaluable resources for chemical, biological, and biomedical fields.

Air versus supplemental oxygen for resuscitation of term or late preterm infants at birth.

This is a protocol for a Cochrane Review (intervention). The objectives are as follows: Primary objective To assess the benefits and harms of air compared with supplemental oxygen for resuscitation of term or late preterm infants at birth in reducing rates of mortality and long-term neurodevelopmental impairment (NDI). Secondary objectives To assess whether the benefits and harms of air compared with supplemental oxygen differ according to different oxygen concentrations, gestational age (GA), whether oxygen was titrated to saturation curves and the income of the study country.

Effect of Annealing Time on Pitting, Intergranular Corrosion, and Hardness of Stainless Steels

Stainless steels are the material that has chromium as a main component. The chromium content reacts with oxygen in air, subsequently, forms thin chromium oxide film on the surface of stainless steels. Thus, when these steels are exposed to high temperature for a long period of time in many applications, chromium carbide could precipitate along the grain boundary and reduce the corrosion resistance. This project is conducted to study annealing time effect on stainless steels when exposed to high temperature at various exposure time periods. Three different kind of stainless steels, namely, AISI 304, AISI 304D and AISI 2205 were used in this study. Stainless steels were heated at 600°C for 0, 6, 24, 48 and 96 hours, then cool down in air. Consequently, the investigations were performed by using double-loop Electrochemical Potentiokinetic Reactivation (DL-EPR) and Cyclic Potentiodynamic Polarization (CPP) to study degree of sensitization and film properties. In addition, chromic acid and oxalic acid were used as reagent of acid etching to observe microstructures. Finally, Vickers hardness test were also conducted. Percentage degree of sensitization increased from 2.93% to 62.20% in AISI 304, increased from 5.26% to 55.54% in AISI 304D and from 12.19% to 69.35% in AISI 2205. The pitting potential decreased from 0.47 mV to 0.23 mV for AISI 304 but remained relatively constant for AISI 304D and AISI 2205. The results indicated that after the specimens were exposed to high temperature for a long period of time, all specimens had more chromium depleted areas, more carbide along the grain boundaries, worse film quality and small changes in hardness value.

THE USE OF FLOW MIXERS IN OXIDIZED BITUMEN PRODUCTION

In the process of road bitumen production, the raw material mixture is fed into an oxidizing column, where it is oxidized with air oxygen. Using this production method, a large amount of oxygen, without reacting, is sent to the scrubber and then to the afterburning furnace. One of the ways to use air oxygen more efficiently in the process of oxidized bitumen production is the use of pre-oxidant mixers. There is also a problem related to such a quality indicator as bitumen aging due to the use of air for mixing commercial bitumen, this problem is solved in a similar way – using a flow jet hydraulic mixer with a cone swirl. This article compares the existing remote gas-liquid cavitation vortex apparatus with a flow jet hydraulic mixer based on building their models in the Ansys CFX program and determining the air concentration in the mixture passing through the mixer. This indicator will reveal the most effective apparatus for the preoxidation of raw materials for bitumen production. A simulation of the flow of tar through a flow jet hydraulic mixer with a conical flow swirl is also performed to determine the turbulence and turbolization of the flow, which shows its effectiveness in mixing compounded bitumen.

Multifunctional Conjugated Polyphenol "Bridge" Capped the Upper Interface of Highly Efficient and Stable Inorganic Perovskite Solar Cells Fabricated in Air.

Carbon-based all-inorganic perovskite solar cells (C-PSCs) are promising alternatives compared with conventional organic-inorganic halide PSCs because of their good thermal stability. However, low carrier transport efficiency and energy level mismatch of the upper interface of the device limit the further improvement of power conversion efficiency (PCE), and all-inorganic perovskites are extremely sensitive to oxygen and humidity, which seriously damages the long-term stability of the device. Upper interface modification is an effective solution to improve the PCE and the stability of devices. Unfortunately, many traditional interface modifiers exhibit insulated and hygroscopic characteristics, which may be harmful to the performance of the device. Herein, a multifunctional conjugated polyphenol "bridge" strategy was adopted on the upper interface of the device fabricated in air, that is, stilbene and polyhydroxy stilbene were capped on perovskite. The results demonstrate that they can effectively enhance the energy level alignment, improve charge transport, passivate defects, suppress nonradiative recombination of interface, and resist oxygen and moisture in air, and the positive effects of modification become more and more pronounced with the increment of the number of hydroxyl groups. The PCE of PSCs was improved from 11.10 to 13.10% after modification. In addition, the unencapsulated modified devices exhibited better stability than the control devices under different environmental conditions.

Ammonium salts of sulfur-containing oxyanions resulting from reaction of sulfur dioxide with aqueous solutions of diethylentriamine and bis(hexamethylene)triamine

Interaction in the system "sulfur dioxide–diethylenetriamine (or bis-(hexamethylene)triamine)–water–air oxygen" results in a mixture of double salts (diethylenetriammonium bis(sulfito)-dithionate (Ia) and bis(sulfito)-sulfate trihydrate diethylenetriammonium (Ib)) or bis(hexamethylene)triammonium sulfate (II). The obtained ammonium salts of sulfur-containing oxyanions Ia, Ib, and II were characterized by the methods of elemental analysis, X-ray structural analysis, X-ray powder diffraction, IR spectroscopy, and mass spectrometry. Compound Ia crystallizes in monoclinic syngony (space group С2/с, a=28.1583(5) Å, b=6.84450(10) Å, c=10.8351(2) Å, =93.776(2)0, V=2083.71(6) Å3, Z=4). Compound Ib crystallizes in rhombic syngony (space group Pbcn, a=18.9777(13) Å, b=10.3131(8) Å, c=11.5414(10) Å, V=2258.9(3) Å3, Z=4). Compound II crystallizes in triclinic syngony (space group P-1, a=11.347(3) Å, b=11.700(5) Å, c=18.913(4) Å, =95.22(3)0, =92,52(2)0, =118,27(4)0, V=2191,36 Å3, Z=2). The IR spectrum of the mixture of salts Ia and Ib shows the valence vibrations of (SO) of sulfite anion (1 and 3), represented by bands at 955, 931, 907, 1026, and 1006 cm–1. Two bands at 566 and 493 cm–1 are the result of the splitting of a doubly degenerate out-of-plane deformation vibration of the 4 (E) of dithionate anion. The bands at 1127 and 1078 cm–1 correspond to the oscillations of as and s of sulfate anion (SO42–). A decrease in the symmetry of the SO42– anion as a result of salt formation is accompanied by the appearance of the band 1 (A1) at 980 cm–1 in its spectrum.

Effect of histone demethylase KDM5B on long-term cognitive impairment in neonatal rats induced by sevoflurane.

Whether repeated inhalation of sevoflurane during the neonatal period causes long-term learning and memory impairments in humans is unclear. Some recent investigations have indicated that general anesthesia drugs affect histone methylation modification and may further affect learning and memory ability. This study aimed to explore the role and mechanism of histone methylation in long-term cognitive dysfunction caused by repeated inhalation of sevoflurane during the neonatal period. Neonatal SD rats were assigned into three groups. Sevoflurane group and sevoflurane +AS8351 group were exposed to 2% sevoflurane for 4 h on postnatal day 7 (P7), day 14 (P7) and day 21 (P21), and the control group was inhaled the air oxygen mixture at the same time. From postnatal day 22 to 36, rats in the +AS8351 group were treated with AS8351 while those in the Sevoflurane group and control group were treated with normal saline. Half of the rats were carried out Y-maze, Morris water maze (MWM), western blot and transmission electron microscope at P37, and the remaining rats were fed to P97 for the same experiment. Neonatal sevoflurane exposure affected histone demethylase expression in hippocampus, changed histone methylation levels, Down-regulated synapse-associated protein expression, impaired synaptic plasticity and long-term cognitive dysfunction and KDM5B inhibitors partially restored the negative reaction caused by sevoflurane exposure. In conclusion, KDM5B inhibitor can save the long-term learning and memory impairment caused by sevoflurane exposure in neonatal period by inhibiting KDM5B activity.

N2 exchanges in hyperbaric environments: towards a model based on physiological gas transport (O2 and CO2).

Decompression sickness can occur in divers even when recommended decompression procedures are followed. Furthermore, the physiological state of individuals can significantly affect bubbling variability. These informations highlight the need for personalized input to improve decompression in SCUBA diving. The main objective of this study is to propose a fundamental framework for a new approach to inert gas exchanges. A physiological model of oxygen delivery to organs and tissues has been built and adapted to nitrogen. The validation of the model was made by transferring the N2 to CO2. Under normobaric conditions (air breathing, oxygen breathing, and static apnea) and hyperbaric conditions, the O2 model replicates the reference physiological Po2 (Spearman correlation tests p<0.001). The inert gas models can simulate inert gas partial pressures under normobaric and hyperbaric conditions. However, the lack of reference values prevents direct validation of this new model. Therefore, the N2 model has been transferred to CO2. The resulting CO2 model has been validated by comparing it with physiological reference values (Spearman correlation tests p<0.01). The validity of the CO2 model constructed from the N2 model demonstrates the plausibility of this physiological model of inert gas exchanges. In the context of personalized decompression procedures, the proposed model is of significant interest as it enables the integration of physiological and morphological parameters (blood and respiratory flows, alveolo-capillary diffusion, respiratory and blood volumes, oxygen consumption rate, fat mass, etc.) into a model of nitrogen saturation/desaturation, in which oxygen and CO2 partial pressures can also be incorporated.

Optimization of the route of the refueling machine to reduce the refueling time: Case study of the BN-800 reactor

Sodium-cooled fast reactors (SFR) are included in the list of fourth-generation nuclear energy systems, the so-called generation IV (GEN-IV). It is the only technology of GEN-IV that possesses the significant practical experience of design, construction, and operation of high-power reactors. Due to the high temperature of the coolant at the BN-600 and BN-800 reactor core outlets, the steam generator produces steam with higher enthalpy, and this significantly increases the efficiency of cogeneration at SFR power plants in comparison with pressured water reactor (PWR) or boiling water reactor (BWR) units. The primary nuclear fuel effectiveness rises due to cogeneration with higher efficiency of a sodium-cooled fast reactor nuclear power plant (NPP) in comparison with thermal reactors. In addition, it is necessary to reduce the reactor refueling outages to improve the nuclear power plant utilization factor.It is possible to reduce the duration of the reactor refueling by the route optimization of the refueling machine movement. The prevailing in the world thermal neutron reactors with water cooling have a refueling machine that points the certain fuel assembly using two coordinates. The fast neutron reactors use sodium as a coolant; thus, there is a problem with its violent reaction with water and air oxygen. Therefore, it is necessary to exclude the contact of sodium and surrounding air during the refueling. To achieve this, the system of refueling machine pointing is used, consisting of two or three eccentrically located rotating plugs with hydraulic locks. The article presents the results of the creation of mathematical models of refueling machine movement and fuel assembly gripping. The time-optimal algorithms for the operation of refueling machines with three rotating plugs are proposed. The use of the new algorithm allows to reduce the time of movement of the grip of the refueling machine by 30–37%.

Effect of Contamination in the Carbon Catalyst Support on Chemical Degradation of Polymer Electrolyte Membranes in Fuel Cells

Introduction One of the key components of polymer electrolyte fuel cells (PEFCs) is the polymer electrolyte membrane (PEM). The PEM facilitates the transport of protons from the anode to the cathode, acts as an electronic insulator to prevent short circuits, and plays a role in preventing the direct reaction of hydrogen gas and oxygen in air. One of the major technical issues with PEMs is their chemical degradation, causing decomposition of their molecular structure. This leads to reduced protonic conductivity, increased hydrogen and oxygen crossover, and reduced mechanical strength, all of which significantly affect the power generation performance and durability of PEFCs (1). In addition, in our laboratory, the use of SnO2 and mesoporous carbon (MC) as cathode catalyst supports has been suggested to suppress membrane degradation (2). However, the relationship between the cathode catalyst materials and the chemical degradation of PEM has not yet been fully understood. Here in this study, we conduct durability tests such as accelerated chemical degradation of PEM in cells using cathode electrocatalysts with different carbon support materials, aiming to clarify the effects of carbon support materials properties (structure, contaminants, and graphitization) on the chemical degradation of electrolyte membranes. Experimental A commercial Pt/KB catalyst (TEC10E50E, Tanaka Kikinzoku Kogyo, Japan) was used as the anode catalyst. Several types of cathode catalysts were applied and compared: the commercial Pt/KB; Pt/MC where Pt was directly deposited on the MC; and various electrocatalysts where Pt was directly deposited on carbon supports such as graphitized AB (acetylene black). The durability test at open circuit voltage (OCV) was performed for 100 h. Before and after the durability test, cell performance, hydrogen crossover current density, and electrochemical surface area (ECSA) were characterized. The degree of membrane degradation was evaluated by measuring fluoride-ion emission rate (FER) by ion chromatography, and membrane thickness by cross-sectional observation with a focused-ion-beam scanning electron microscope (FIB-SEM), as illustrated in Fig.1. Moreover, contaminants and graphitization of the carbon support materials were also analyzed, and their relationship to membrane degradation was considered. Results and discussion The results of OCV holding tests up to 100 h for four different MEAs are shown in Fig. 2. The voltage drop in using Pt/MC as cathode catalysts was smaller than that in using Pt/KB. The FER of Pt/MC as cathode catalysts was lower than that of Pt/KB as shown in Fig. 3, suggesting that the use of MC as carbon supports may suppress PEM degradation. In this presentation, we will show the effects of carbon support materials properties (structure, contaminants, and graphitization) in cathode catalysts on PEM degradation, and discuss possible mechanisms based on the characteristics of various carbon supports. Acknowledgements This paper is based on results obtained from a project, JPNP20003, commissioned by the New Energy and Industrial Technology Development Organization (NEDO). An educational part for young scientists was supported by the Japan Science and Technology Agency (JST) through the program “Adopting Sustainable Partnerships for Innovative Research Ecosystem” (ASPIRE), Grant Number JPMJAP2307. The presenting author (S. Nakamura) is supported by the Miyamoto Jun-ichi Hydrogen Research Award, and the Kyushu University Q-PIT Support Program for Young Researchers and Doctoral Students. References M. Zatoń, J. Rozière, and D. J. Jones, Sustain. Energy Fuels, 1, 409 (2017).S. Nakamura, T. Ogawa, Z. Gautama, Z. Noda, M. Yasutake, S. M. Lyth, J. Matsuda, A. Hayashi, M. Nishihara, and K. Sasaki, ECS Trans., 112 (4), 315 (2023). Figure 1

Oxygen Evolution Reaction Activity of Highly Crystalline Hydrated Cobalt Oxyhydroxide Synthesized with Soft Chemistry

Introduction Zinc-air secondary batteries are expected to have high energy density because oxygen in ambient air can be used as the active material. They are also expected to satisfy high safety standards owing to the aqueous electrolyte solutions and open structure. In addition, low cost is expected since zinc is a relatively cheap metal compared to lithium. Because of these features, Zinc-air secondary batteries are attracting attention as a next-generation large-scale energy storage device. One of the challenges for commercializing this battery system is the low energy conversion efficiency caused by the large overvoltage of the air electrode. To solve this problem, oxygen evolution reaction (OER) catalysts have been intensively researched, and Ba0.5Sr0.5Co0.8Fe0.2O3-δ (BSCF) and Ca2FeCoO5 (CFCO) have been developed as OER catalysts having higher activity than conventional noble metal oxide catalysts. Since the active sites of BSCF and CFCO are reported as partially Fe-substituted CoOOH phases1,2, it is essential to understand OER characteristics of partially Fe-substituted CoOOH phases. However, the effects of the crystallinity and Fe-substitution ratio on OER activity have not been clarified. This is mainly because metastable hydrated CoOOH is conventionally synthesized at relatively low temperatures. On the other hand, we have successfully synthesized highly crystalline hydrated NixFe1–xOOH using soft chemistry and clarified the effect of crystallinity and Fe-substitution ratio on the OER activity3. In this study, we synthesized highly crystalline hydrated CoOOH using soft chemistry and evaluate its OER activity to elucidate factors controlling it. Experimental Hydrated CoOOH was synthesized with two-step soft chemistry following the report by Sakurai et al. 4. First, Na0.74CoO2 was obtained by calcination of Co3O4:Na2CO3 =40:60 mol% at 900 °C for 12 h. Then, synthesized Na0.74CoO2 was stirred in 7.8 mmol dm–3 Br2 / CH3CN to obtain Na0.358CoO2 by extracting Na. Finally, Na0.358CoO2 was hydrated by refluxing with ultra-pure water at 100 °C for 24 h. The synthesized samples were characterized with powder X-ray diffraction (XRD). Results and discussion Figure 1 shows a XRD pattern of the synthesized sample. Though relatively broad unidentified peak is observed at around 8 °, the diffraction pattern of hydrated CoOOH is observed as a main phase. Its OER performance in an aqueous solution of KOH will be presented at the site.References1) K. J. May, C. E. Carlton, K. A. Stoerzinger, M. Risch, J. Suntivich, Y. L. Lee, A. Grimaud, Y. S. Horn, J. Phys. Chem. Lett., 3, 3264 (2012).2) E. Tsuji, T. Motohashi, H. Noda, D. Kowalski, Y. Aoki, H. Tanida, J. Niikura, Y. Koyama,M. Mori,H. Arai,T. Ioroi,N. Fujiwara,Y. Uchimoto,Z. Ogumi, H. Habazaki., ChemSusChem., 10, 2864 (2017).3) A. Ikezawa, S. Koito, H. Arai, Abs.#1I23, The 90th ECSJ Annual Meeting (2023).4) H. Sakurai, K. Takada, T. Sasaki, F. Izumi, R. A. Dilanian, E. Takayama-Muromachi, J Phys. Soc. Jpn., 73, 2590 (2004).This work was partially supported by JRP-LEAD with DFG (JPJSJRP20221602) Figure 1

Sensors for Inflatable Lunar Habitat Construction

Lunar habitat is necessary for human exploration, especially for long duration space missions. For lunar habitat consturction, there are several other environmental hurdles to overcome than earth and constant internal pressure of habitat is added if the structure is to be inflatable.Among these hurdles, high energetic ions and particles from solar radiation and consequence extreme temperature difference may be protected with higher priority at least to secure survival environment for humans.In Korea Institute of Civil engineering and building Technology, new research project was launched in 2023 to design basic plan of lunar habitat construction on the moon and one of research topics is how to secure indoor environment of inflatable lunar habitat under that harsh lunar environment.Multi layred shell structured wall was suggested from previous project and research results and was selected to the optimum initial structure to start. Multi layred shell is mainly consisted of several highly strong and heat resistant fabric such as Kevlar or Vectran in webbing with other ion or particle protective layers and thermal insulation.Key environmental parameters for monitoring are internal air pressure, oxygen cencentration, temperature, humidity, and high energy particles by secondary radiation. Therefore, it is essential how to design and configure total sensing and monitoring system for inflatable habitat for long duration human exploration. Environmental, radiation, and inflatable structure monitoring sensors are summarized and composed to secure indoor enviroment and provide environmental quality data to HVAC system in further.

Enhanced degradation of aqueous caffeine via cylindrical dielectric barrier discharge plasma: Efficacy and toxicity insights

An environmentally friendly approach for caffeine degradation was explored in this study utilizing cylindrical dielectric barrier discharge (CDBD) plasma. The current-voltage characteristics and the plasma parameters of the CDBD, such as the electron temperature, electron density, density of nitrogen excited states, vibrational temperature, and rotational temperature, were assessed through electrical and optical characterization respectively. Fourier-transform infrared spectroscopy (FTIR) was employed to evaluate the reactive oxygen and nitrogen species (RONS) in the plasma-treated air. The physicochemical properties of deionized water (DW) were measured. To gain a deeper insight into the role of RONS in caffeine degradation, their concentrations in DW were analyzed. Furthermore, the effects of initial concentration, sample volume, and pH on caffeine degradation were investigated. The highest degradation of caffeine was 94% at initial concentration of 50 mg L−1, sample volume 50 mL and in neutral pH. Liquid chromatography–mass spectrometry (LC-MS) was then used to propose the degradation pathway for caffeine. The major reactive species involved in caffeine degradation was ozone. Finally, the phytotoxicity and cytotoxicity of caffeine were assessed before and after plasma treatment with plasma-treated caffeine (PTC) showing minimal toxicity to both plants and cells.

Investigation of the sorption activity of native coals to air oxygen

The influence of the gaseous medium during sample preparation, the granulometric composition, the duration of contact with air and the stage of metamorphism on the process of oxygen sorption from the air was established. It is shown that conducting sample preparation in an air atmosphere leads to primary oxidation of the outer surface of the coals, which introduces an error in determining the oxygen sorption rate constant. Fine coal fractions (0-0.2 mm) with a more developed outer surface have increased oxygen absorption activity. The rate of oxygen sorption is maximal at the initial moment of the interaction of active carbons with air and decreases with the duration of contact. The least metamorphosed hard coals of the D brand with a high content of reactive functional groups and a developed porous structure are characterized by the greatest chemisorption activity.

Numerical Investigation on the Effect of Air Humidification and Oxygen Enrichment on Combustion and Emission Characteristics of Gas Boiler

Gas boilers exhibit thermal inefficiency and unsatisfying pollutant emissions. In this study, numerical simulations were conducted to examine the effect of humidified oxygen-enriched air on methane combustion in a furnace and the effects of different premixed ratios of air on the temperature field inside the furnace, intermediate product OH groups, component concentration distribution, and pollutants. Although humidification of ambient air effectively reduced the flame center temperature and mass concentration of the NOx generated during combustion in the furnace, the highest growth rate of CO concentration at the furnace outlet was 18.6%. Humidification of oxygen-enriched air increased the center temperature and outlet NO concentration of the furnace compared with those during no oxygen enrichment, but the outlet CO concentration showed a decreasing trend, with the highest decrease rate of 34.6%. This study determined an optimal CO–air premix ratio with a moisture concentration of 50 g/kg dry air and an oxygen concentration of 23%. The air humidification and oxygen enrichment technology proposed in this article provides a technical reference for low nitrogen transformation of existing gas boilers.

Laser-induced plasma analysis of ammonia-oxygen and ammonia-oxygen-enriched-air flames at elevated pressures

This study employed Laser-induced breakdown spectroscopy (LIBS) to measure the fuel-oxidizer ratio (FOR) of ammonia combustion with oxygen-enriched air and pure oxygen flames at elevated pressures (100 - 300 kPa). The correlations between the spectral line intensity ratios of nitrogen (N), hydrogen (H), oxygen (O), and equivalence ratio were used to quantify the FOR of flames at various pressures. The effect of pressure on the stability and precision of the calibration profiles for the elemental intensity ratios in flames was investigated. It was observed that the H/O correlation decreases with pressure increase for both ammonia flames. N/O correlations decrease with elevated pressure for the ammonia-oxygen flame. Furthermore, the nitrogen (NII) spectral emission lines at 568 nm and 595 nm were used to estimate the plasma temperature, while the hydrogen (Hα) line at 656 nm was used for electron number density measurements.

Formation of esters by the Baeyer–Villiger reaction during oxidation of 1-chlorohexadecane with air oxygen in the presence of cobalt hydroxystearate– N-hydroxyphthalimide catalytic system

To obtain multifunctional additives for the processing of polyvinyl chloride, the process of oxidation of 1-chlorohexadecane with atmospheric oxygen in the presence of the catalytic system cobalt hydroxystearate– N-hydroxyphthalimide was studied. It was found that the ongoing Baeyer–Villiger reaction with the participation of hydroperoxides leads to a high content of esters in the oxidate, which improves the plasticizing effect of the resulting additives.

3D printed oxygen gas sensor with a Pt-nanoparticles decorated N-doped carbon catalyst and an amine-polymer composited ionic liquid gel electrolyte

A 3D-printed electrochemical oxygen gas sensor was developed using a Pt nanoparticle-decorated N-doped carbon (PtNC) catalyst and an ionic liquid gel electrolyte incorporated with polyethyleneimine. At first, N-doped carbon particles were synthesized hydrothermally, followed by the decoration of a tiny amount of Pt nanoparticles using a microwave reactor. The working electrode was printed with a composite of high-impact polystyrene (HIPs), graphite powder (Gr), and a PtNC catalyst (HIPs/Gr/PtNC), then counter and reference electrodes were separately printed without the PtNC catalyst. The sensing materials were characterized using various analytical methods, including SEM, XPS, Raman, ICP-AES, CV, and EIS. Prior to detecting oxygen gas, the 3D sensor surface was pretreated with potential cycling in an acidic solution. Additionally, a composite gel electrolyte was prepared by incorporating polyethyleneimine into an ionic liquid, which was then coated onto the sensor surface to enhance sensitivity and ensure long-term stability. The analytical parameters using the final sensor were optimized in terms of Pt contents, 3D-printing polymer type, and ionic liquid gel concentration. The amperometric measurements demonstrated a wide dynamic range from 0.1 % to 100 % with the detection limit of 0.13 ± 0.05 % at a 90 % response time of 3.6 ± 0.4 s. To validate the reliability of the proposed sensor, the measurement of O2 content was performed for room air and standard oxygen gas, revealing reliable and stable results for six months.