Concentration In Chamber Research Articles

The Impact of Hydrogen on Flame Characteristics and Pollutant Emissions in Natural Gas Industrial Combustion Systems

To improve energy savings and emission reduction in industrial heating furnaces, this study investigated the impact of various molar fractions of hydrogen on natural gas combustion and compared the results of the Non-Premixed Combustion Model with the Eddy Dissipation Combustion Model. Initially, natural gas combustion in an industrial heating furnace was investigated experimentally, and these results were used as boundary conditions for CFD simulations. The diffusion flame and combustion characteristics of natural gas were simulated using both the non-premixed combustion model and the Eddy Dissipation Combustion Model. The results indicated that the Non-Premixed Combustion Model provided simulations more consistent with experimental data, within acceptable error margins, thus validating the accuracy of the numerical simulations. Additionally, to analyze the impact of hydrogen doping on the performance of an industrial gas heater, four gas mixtures with varying hydrogen contents (15% H2, 30% H2, 45% H2, and 60% H2) were studied while maintaining constant fuel inlet temperature and flow rate. The results demonstrate that the Non-Premixed Combustion Model more accurately simulates complex flue gas flow and chemical reactions during combustion. Moreover, hydrogen-doped natural gas significantly reduces CO and CO2 emissions compared to pure natural gas combustion. Specifically, at 60% hydrogen content, CO and CO2 levels decrease by 70% and 37.5%, respectively, while NO emissions increase proportionally; at this hydrogen content, NO concentration in the furnace chamber rises by 155%.

An update on soil gas harvesting technique as a non-depleting source of 222Rn for a large volume calibration chamber for long-term exposure experiments

ObjectiveTo demonstrate the versatility of the natural soil gas harvesting technique, coupled with a semi-dynamic injection algorithm, as an efficient and reliable source for continuous 222Rn delivery to a large-volume calibration chamber across different soil conditions and climatic conditions. MethodsLong-term experiments were performed during three seasons of a year in a tropical monsoonal climatic region with high rainfall on the Southwest Coast of India. Soil gas extraction was performed using soil-gas probes, inserted to ∼ 1 m deep into the ground. Soil gas was harvested at a flow rate of 60 lpm, passed through a moisture trap, a 222Rn progeny filter, and a delay volume and pumped into a 222Rn calibration chamber of volume 22.7 m3. Continuous monitoring of 222Rn concentration in the chamber was performed using ionization chamber-based reference monitors. To achieve and maintain the desired 222Rn concentration values in the calibration chamber, the semi-dynamic injection method was adopted, in which the 222Rn concentration in the soil gas was monitored periodically, and injection into the chamber was controlled using a well-defined pumping algorithm. Three ranges of 222Rn concentration values were chosen as the target values to be maintained in the calibration chamber for long-term experiments (15 d): (i) low concentration (500 - 1,000 Bq/m3), (ii) medium concentration (1,000 - 10,000 Bq/m3), and (iii) high concentration (10,000 – 25,000 Bq/m3). ResultsThe achieved 222Rn concentration values were in good agreement with the target values, with deviations of 12%, 8% and 5% for the low, medium and high concentration exposures, respectively, during the summer season. During the monsoon season, the deviations between the target and the achieved concentration values were 12%, 10% and 5% for low, medium and high concentration exposures, respectively, and the corresponding deviations were 12%, 4%, and 5% for the winter season. These deviations are well within the cumulative uncertainty associated with the measurements. ConclusionsThe results of this study conclusively demonstrate that the soil gas harvesting method, when coupled with the semi-dynamic injection approach, is a reliable method for generating and maintaining the desired 222Rn concentration in the large volume calibration chamber during different seasons and environmental conditions.

Study on CO dispersion characteristics and isolation door control technology of refuge chamber in coal mine

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.

The bio-cathode of microbial fuel cells systems: Performance analysis under different microbial community conditions

This study aims to investigate the conversion of different microbial community compositions in the cathode chamber in a dual-chamber bioelectrochemical system. A denitrifying bacterial community, or sludge, was enriched for denitrification by microbial consortia and subsequently acclimatized within the cathodic chamber of microbial fuel cells, either within a mixed microbial community sludge microbial fuel cell (M-MFC) or a pure culture of microorganisms in a microbial fuel cell (P-MFC). The bioelectrochemical systems were treated with different nitrate concentrations in the cathodic chamber: the MFC with low concentration nitrate (MFC1, 25 mg/L nitrate; MFC2 50 mg/L nitrate), the MFC with medium concentration nitrate(MFC3, 75 mg/L nitrate; MFC4 100 mg/L nitrate), and MFC with high concentration nitrate (MFC5, 125 mg/L nitrate; MFC6 150 mg/L nitrate; MFC7 175 mg/L nitrate), and the initial COD in the anodic chamber was based on demand(C to N ratio is 5). M-MFC exhibited better-electrogenerated capability than P-MFC. However, P-MFC exhibited better nitrogen removal performance compared to M-MFC. The best performance was attained by both types of MFCs when the nitrate content was 100 mg/L. The maximum output voltages in M-MFC4 and P-MFC4 were 449 mV and 171 mV, respectively. The average conversion rate of M-MFC4 and P-MFC4 were 2.9 mg*L−1 *h−1 and 10.5 mg*L−1 *h−1, respectively. The analysis of the microbial community of two treated MFCs in the cathode chamber in the optimal state indicated that non-electrode denitrification predominantly occurs in P-MFC. The cathode chambers were mostly populated by denitrifying microorganisms. The dominant species in M-MFC were Azonexus, Zoogloea, Ignavibacterium, and Pirellula, and the dominant species in P-MFC were Comamonas, Aeromonas, and Acidovorax. The species was assessed by qPCR analysis, and the results validated the use of a bacterial consortium for domestication as a more suitable method to improve the stability and performance of the MFCs.

Synthesis and characterization of an oxygen-controlled CuO/SnO2 sensor for NO2 detection

Various nanostructures can be developed through oxygen-controlled sputter, transitioning from a triangular configuration to a grain with a smooth surface. In the current study, the P-N junction of double-layer CuO/SnO2 was generated for gas sensing application, where the nanostructure is varied by modifying argon to oxygen concentration in the sputter chamber. NO2 gas is tested for triangular CuO/SnO2 sensor application, and sensing results revealed a sensor response of 10.6 (Rg/Ra) at 0.2 ppm and a response of 57.2 (Rg/Ra) at 1 ppm. In order to evaluate the anti-interference performance, the sensing performance was tested using H2S, NH3, CO, and H2 to determine the sensor's anti-interference performance with good reproducibility.

DIELECTRIC BARRIER DISCHARGE BASED PLASMA DEVICE FOR COLD STERILIZATION IN WATER WITH ADDITIONAL ULTRASONIC CAVITATION

A prototype of plasma sterilizer based on dielectric barrier discharge (DBD) with additional ultrasonic cavitation for cold sterilization has been developed. It provides sterilization of reusable small dental instruments, and components made from corrosion-resistant metals and alloys (stainless steel, titanium, etc.), as well as surgical instruments, implants, small drills, plastic sundries, ozone resistant medical rubbers (silicone, etc.), polymers, epoxy resins and glass. The sterilizer is well suited for dentistry and can be used in medical, sanatorium, outpatient and other medical institutions, as well as in military field surgery. The volume of the sterilization bath is 2.5 l. The ozone concentration at the output of the ozone generator is 35…52 mg/l, the ozone concentration in the sterilizer chamber is 6.5…8 mg/l, depending on the water temperature and its volume in the bath. The dependence of the increase of ozone concentration in water on time at different oxygen flow rates is monitored.

Knock-out of SlDMR6-1 in tomato promotes a drought-avoidance strategy and increases tolerance to Late Blight

The DOWNY MILDEW RESISTANCE 6 (DMR6) protein is a 2-oxoglutarate (2OG) and Fe(II)-dependent oxygenase, involved in salicylic acid (SA) metabolism. SA is recognized as an abiotic stress-tolerance enhancer, and in tomato the inactivation of DMR6 was found increase its level and induce disease-resistance against several pathogens. By applying the CRISPR/Cas9 technique, we generated Sldmr6-1 tomato mutants and tested their tolerance to drought as well as to Late Blight. Wild-type tomato cultivar ‘San Marzano’ and its Sldmr6-1 mutants were subjected to water deprivation for 7 days. WT plants exhibited severe wilting, while T2Sldmr6-1 mutants showed turgid leaves and maintained higher Soil Relative Water Content. Eco-physiological measurements highlighted that Sldmr6-1 mutants adopted a water saving behavior reducing transpiration rate by decreasing stomatal conductance. Under drought stress the assimilation rate decreased as well, resulting in no alteration of the CO2 concentration in the sub-stomatal chamber and increasing the Water Use Efficiency. Furthermore, in Sldmr6-1 mutants the drought stress induced up-regulation of the anti-oxidant related genes SlAPX and SlGST as well as down-regulation of SlCYP707A2 gene, which is involved in ABA catabolism. At last we highlighted, for the first time in tomato, that Sldmr6-1 mutants exhibited a reduced susceptibility to Phytophthora infestans, the causal agent of Late Blight.

Benefits of combining supersaturating and solubilizing formulations – Is two better than one?

A variety of enabling formulations has been developed to address poor oral drug absorption caused by insufficient dissolution in the gastrointestinal tract. As the in vivo performance of these formulations is a result of a complex interplay between dissolution, digestion and permeation, development of suitable in vitro assays that captures these phenomena are called for. The enabling-absorption (ENA) device, consisting of a donor and receiver chamber separated by a semipermeable membrane, has successfully been used to study the performance of lipid-based formulations. In this work, the ENA device was prepared with two different setups (a Caco-2 cell monolayer and an artificial lipid membrane) to study the performance of a lipid-based formulation (LBF), an amorphous solid dispersion (ASD) and the potential benefit of combining the two formulation strategies. An in vivo pharmacokinetic study in rats was performed to evaluate the in vitro-in vivo correlation. In the ENA, high drug concentrations in the donor chamber did not translate to a high mass transfer, which was particularly evident for the ASD as compared to the LBF. The solubility of the polymer used in the ASD was strongly affected by pH-shifts in vitro, and the ph_dependence resulted in poor in vivo performance of the formulation. The dissolution was however increased in vitro when the ASD was combined with a blank lipid-based formulation. This beneficial effect was also observed in vivo, where the drug exposure of the ASD increased significantly when the ASD was co-administered with the blank LBF. To conclude, the in vitro model managed to capture solubility limitations and strategies to overcome these for one of the formulations studied. The correlation between the in vivo exposure of the drug exposure and AUC in the ENA was good for the non pH-sensitive formulations. The deconvoluted pharmacokinetic data indicated that the receiver chamber was a better predictor for the in vivo performance of the drug, however both chambers provided valuable insights to the observed outcome in vivo. This shows that the advanced in vitro setting used herein successfully could explain absorption differences of highly complex formulations.

Sulfur autotrophic electrodialysis ion exchange membrane bioreactor (SEDIMB) for nitrate removal in water: Synergism and adaptability of electrodialysis and sulfur autotrophy

In this study, the novel sulfur autotrophic electrodialysis ion-exchange membrane bioreactor (SEDIMB) with high denitrification performance was developed without the addition of carbon source. Sulfur autotrophic denitrification occurs at the same time of nitrate enrichment by electric field to achieve harmless nitrate transformation in water. The final nitrate concentration in water chamber was 2.16 mg-N/L (removal efficiency of 94.49 %) at an initial nitrate concentration of 40 mg-N/L, with the maximum nitrate concentration in biological chamber of 4.09 mg-N/L. Nitrate removal in water chamber of the SEDIMB conformed to the first-order kinetic model (R2 = 0.98) and reaction rate constant K1 = 0.0030 (1/min). The effect of environmental variables (i.e., voltage, initial nitrate concentration and water body) on the SEDIMB denitrification performance was investigated. Increasing voltage could promote nitrate migration in water chamber, and when the voltage was 7 V, initial nitrate concentrations of 20 ∼ 60 mg-N/L was effectively removed (all > 93.54 %). Moreover, the change of water body (i.e., tap water, lake water and deionized water) did not affect denitrification performance of SEDIMB. Microbial community structure analysis indicated that Betaproteobacteria were dominant in the SEDIMB. Membrane characterizations (ATR-IR, SEM and CLSM) confirmed that the bacteria in biological chamber tended to accumulate and grow on one side of the anion exchange membrane (AEM), while could not affect the selective permeability of AEM.

Numerical modeling of the non-equilibrium condensation in multi-component flows through the high expansion ratio nozzles

Excessive flow expansion in the thruster nozzles reduces the flow temperature and pressure. This provides conditions for the condensation phenomena in the nozzle, which can affect the thrust performance of thrusters. In this paper, the condensation effect of water components in the decomposition products of hydrogen peroxide in a typical thruster nozzle is modeled. To describe the state and properties of the real gas mixture, the Peng-Robinson equation of state is used. Moreover, the effects of H2O2 concentration and nozzle profile on the condensation and nozzle performance parameters are studied. The results show that by more flow expansion and crossing the saturated state of condensable components, the thrust coefficient improves up to 6%. This improvement decreases by increasing the H2O2 concentration in the reaction chamber for a fixed nozzle expansion ratio. Due to the small growth of droplets during the free molecular regime of the droplet growth in the high-speed flow, the non-equilibrium condensation continues until the nozzle outflow. In addition, although all the profiles have the same expansion ratio for nucleation start, increasing the nozzle length results in larger nano-droplets, more liquid mass fraction formation up to 4%, and moving the Wilson point to the further upstream sections in the nozzle.

Photosynthetic microalgae microbial fuel cells for bioelectricity generation and microalgae lipid recovery using Gd-Co@N-CSs/NF as cathode

Photosynthetic microalgae microbial fuel cells (PMMFCs) have an enormous potential for wastewater treatment and bioenergy recovery. However, to overcome low power generation problem, it is crucial to understand how the operational parameters influence the pathways and mechanisms of PMMFCs performance. In this study, microalgae (Chlorella vulgaris, Chlorella sp., Tetradesmus obliquus and Microcystis aeruginosa), light intensity (1400, 2100 and 3200 lx) and light/dark cycle (12/12, 18/6 and 24/0) were screened to promote the bioenergy recovery of PMMFCs. The highest power generation and electrochemical activity were obtained for Chlorella vulgaris under 3200 lx and cycle 18/6, with the maximum power density of 2.0 W m−3, and the lowest charge transfer resistance of 26.60 Ω and Tafel slope of 44.74 mV dec−1. Correlation analysis showed a significant negative correlation between NH4+-N concentration in the cathode chamber and output voltage. Structural equation model further elucidated that NH4+-N indirectly regulated the output voltage via the negative association with dissolved oxygen. In addition, the by-product lipid reached 145 mg g−1 dry mass. Furthermore, the specific gravity, iodine value, and cetane number of the fatty acids met the production standards for biodiesel. The electroactive bacteria Propionibacteriaceae (24.45%) were the dominant genera. This study provided suitable microalgae species and crucial operating conditions for bioenergy recovery from electrochemical systems with high catalytic activity.

Purification of surface water by using the corona discharge method

Purpose. The primary objective of this research is to develop a technology for achieving water quality at the level of Maximum Permissible Concentrations (MPC) required by sanitary regulations and norms. Methods. To meet these regulatory requirements, experimental studies were conducted to analyze the chemical and microbiological composition of water, focusing on parameters such as the total microbial count (quantity/ml), coliform bacteria (quantity/ml), coliphages (quantity/100 ml), clostridia (cl/20 ml), and other harmful substances. The research also examined water disinfection processes depending on the autumn and winter seasons of the year. Findings. To assess the device’s effectiveness, the research determined the optimal ozone concentration and contact time in the disinfection chamber. The findings indicate that 0.6 grams per hour (G = 0.6 g/hour) of ozone (O3) per cubic meter of surface water is sufficient for the removal of harmful microbiological substances. Originality. The primary innovation in this research lies in the establishment of parameters for an ozone generator utilizing a novel corona discharge method. The study introduces both theoretical frameworks and practical methodologies for effectively disinfecting surface waters using this innovative technique. Practical implications. This case study offers insights that can be applied and replicated in regions facing similar water quality challenges.

Design of an economic, portable, compact, and indigenous instrument setup for measuring sensing characteristics of thin film gas sensors.

Thin film gas sensor characterization is very demanding for various applications because of technical design trade-offs in commercially available gas sensors. For gas sensing characterization, a suitable gas-testing experimental setup is very much needed in this context. Various factors in the experimental setup can affect a thin film gas sensor's response beyond gas exposure. These factors include the test chamber's volume, relative humidity, uniform operating temperature, uniform pressure, uniform gas density, uniform gas distribution, uniform gas concentration in the gas chamber, and uniform relative gas flow velocity over the surface of the sensor. All these environmental parameters, not being so predictive in nature, induce an inherent design trade-off in the experimental setup design. Although all the commercially available gas testing experimental setups are equally good considering the dedicated purpose for which they are made. However, all of them are for generic applications but not for specific applications because of their inherent trade-offs in their usability features. Those trade-offs always provide an opportunity to introduce a new setup with its own unique advantages. Hence, in this article, we have presented a portable, compact, indigenous gas sensing experimental setup for studying the performance of gas sensors. We have characterized and tested the setup using a ZnO based thin film gas sensor when exposed to CO2 gas at concentrations ranging from 1445 to 4631 ppm. The proposed gas sensing setup's compact size offers unique advantages, including portability and compatibility for uniform environmental conditions.

Enhanced hydrogen gas sensing characteristics of CuO/ZnO heterojunction for thickness-dependence and its application

In this study, we experimentally verified the synthesis of ZnO and CuO thin films using a droplet-based hydrothermal method and their hydrogen sensing performance. The hydrogen gas detection performance of the fabricated heterostructured gas sensor was evaluated based on the results of an experiment conducted while controlling the temperature and hydrogen concentration in the gas chamber. According to the responses of single metal oxide sensors made of each ZnO and CuO and their heterojunction sensors, CuO deposited with 7 cycles on 5 cycles of ZnO had a resistance change rate of about 164 % and the change of the resistance took 3 s in the environment of 4 % hydrogen at 300 °C. This sensor showed the highest response rate and fastest reaction time out of all. CuO/ZnO showed the highest reaction at 300 °C, confirming its selective reaction to hydrogen. To solve the problem of metal oxide-based gas sensors with low selectivity, the operating principle of the heterojunction between metal oxide that has selective gas reactivity was analyzed and experimentally verified. Additionally, the fabricated sensor was confirmed to have selective responsiveness to different gases at various temperatures. Using these characteristics, it was confirmed that this heterostructure based sensor can be used as a sensor array for electronic nose that could classify unknown gases using the same sensor at various temperatures.

Sea spray emissions from the Baltic Sea: comparison of aerosol eddy covariance fluxes and chamber-simulated sea spray emissions

Abstract. To compare in situ and laboratory estimates of sea spray aerosol (SSA) production fluxes, we conducted two research campaigns in the vicinity of an eddy covariance (EC) flux tower on the island of Östergarnsholm in the Baltic Sea during May and August 2021. To accomplish this, we performed EC flux measurements for particles with diameters between 0.25 and 2.5 µm simultaneously with laboratory measurements using a plunging jet sea spray simulation chamber containing local seawater sampled close to the footprint of the flux tower. We observed a log-linear relationship between wind speed and EC-derived SSA emission fluxes, a power-law relationship between significant wave height and EC-derived SSA emission fluxes, and a linear relationship between wave Reynolds number and EC-derived SSA emission fluxes, all of which are consistent with earlier studies. Although we observed a weak negative relationship between particle production in the sea spray simulation chamber and seawater chlorophyll-α concentration and a weak positive relationship with the concentration of fluorescent dissolved organic matter in seawater, we did not observe any significant impact of dissolved oxygen on particle production in the chamber. To obtain an estimate of the size-resolved emission spectrum for particles with dry diameters between 0.015 and 10 µm, we combined the estimates of SSA particle production fluxes obtained using the EC measurements and the chamber measurements in three different ways: (1) using the traditional continuous whitecap method, (2) using air entrainment measurements, and (3) simply scaling the chamber data to the EC fluxes. In doing so, we observed that the magnitude of the EC-derived emission fluxes compared relatively well to the magnitude of the fluxes obtained using the chamber air entrainment method as well as the previous flux measurements of Nilsson et al. (2021) and the parameterizations of Mårtensson et al. (2003) and Salter et al. (2015). As a result of these measurements, we have derived a wind-speed-dependent and wave-state-dependent SSA parameterization for particles with dry diameters between 0.015 and 10 µm for low-salinity waters such as the Baltic Sea, thus providing a more accurate estimation of SSA production fluxes.

Real-Time Measurement of Antiglaucoma Drugs in Porcine Eyes Using Boron-Doped Diamond Microelectrodes.

The primary treatment for glaucoma, the most common cause of intermediate vision impairment, involves administering ocular hypotensive drugs in the form of topical eye drops. Observing real-time changes in the drugs that pass through the cornea and reach the anterior chamber of the eye is crucial for improving and developing safe, reliable, and effective medical treatments. Traditional methods for measuring temporal changes in drug concentrations in the aqueous humor employ separation analyzers such as LC-MS/MS. However, this technique requires multiple measurements on the eyes of various test subjects to track changes over time with a high temporal resolution. To address this issue, we have developed a measurement method that employs boron-doped diamond (BDD) microelectrodes to monitor real-time drug concentrations in the anterior chamber of the eye. First, we confirmed the electrochemical reactivity of 13 antiglaucoma drugs in a phosphate buffer solution with a pH of 7.4. Next, we optimized the method for continuous measurement of timolol maleate (TIM), a sympathetic beta-receptor antagonist, and generated calibration curves for each BDD microelectrode using aqueous humor collected from enucleated porcine eyes. We successfully demonstrated the continuous ex vivo monitoring of TIM concentrations in the anterior chambers of these enucleated porcine eyes. The results indicate that changes in intracameral TIM concentrations can be monitored through electrochemical measurements using BDD microelectrodes. This technique holds promise for future advancements in optimizing glaucoma treatment and drug administration strategies.

Numerical simulation of charged characteristics of scramjet combustion products

The combustion of the engine in the air vehicle causes the presence of charged particles in the jet stream, and the electric field displayed varies with engine type and fuel characteristics. In order to show the magnitude and distribution of charged particles in combustion products during scramjet operation, we constructed microphysical model and fluid calculation model based on the physical characteristics of supersonic combustion to simulate the variation of charged particles concentration in the scramjet combustion chamber and the charge density distribution outside the combustion chamber. The obtained results show that the charged particles in combustion products are mainly composed of ions, electrons, ion clusters, and charged soot particles. The electron concentration can be almost negligible at the exit of the combustion chamber. The other charged particles in the combustion products are ejected into the atmosphere with the jet. The charge density distribution of the jet has a certain symmetry in a short time due to the influence of the flow field. It is found that the type of fuel and the conductivity of the surface materials in the combustion chamber affect the electrified properties of the combustion products to some extent. This study has a reference value for further analysis of the detectable electric field generated during scramjet operation.

Inhalation of gaseous hypochlorous acid and its effect on human respiratory epithelial cells in laboratory model systems.

During the disinfection of indoor spaces using gaseous hypochlorous acid (HOCl(g)), inhalation is the most common route of exposure for humans. In this study, an artificial human respiratory tract model was exposed to 12-140 ppb HOCl(g) at an aspiration flow rate of 800 mL/s for 15 h in a 1 m3 chamber. The respiratory tract model was equipped with 5th order bronchi and all gas-contact parts were made of silicone rubber with no other chlorine-consuming substances. The concentration of HOCl(g) reaching the lung pseudo-space was approximately 47.4% of the HOCl(g) concentrations in the chamber and was calculated to be very close to zero when the chamber concentration was less than 20.5 ppb. The disappearance of HOCl(g) during inhalation is likely due to the adsorption of HOCl(g) on the gas-contact silicone rubber surfaces. The cytotoxicity of HOCl(g) on respiratory epithelial cells was also examined using human air-liquid-interface airway tissue models. Human nasal epithelium and bronchiolar epithelium were exposed to 100 ppb and 500 ppb HOCl(g) for 8 h and 5 d, respectively. No significant effects of HOCl(g) on cell viability and ciliary activity were observed in any cell type, indicating that low concentrations of HOCl(g）, less than 500 ppb, had no cytotoxic effect.

Variation of indoor radon concentration in a walk-in type test chamber under controlled environmental conditions

Variation of indoor radon concentration in a walk-in type test chamber under controlled environmental conditions

Bipolar membrane electrodialysis integrated with in-situ CO2 absorption for simulated seawater concentrate utilization, carbon storage and production of sodium carbonate

In the context of carbon capture, utilization, and storage, the high-value utilization of carbon storage presents a significant challenge. To address this challenge, this study employed the bipolar membrane electrodialysis integrated with carbon utilization technology to prepare Na2CO3 products using simulated seawater concentrate, achieving simultaneous saline wastewater utilization, carbon storage and high-value production of Na2CO3. The effects of various factors, including concentration of simulated seawater concentrate, current density, CO2 aeration rate, and circulating flow rate of alkali chamber, on the quality of Na2CO3 product, carbon sequestration rate, and energy consumption were investigated. Under the optimal condition, the CO32– concentration in the alkaline chamber reached a maximum of 0.817 mol/L with 98 mol% purity. The resulting carbon fixation rate was 70.50%, with energy consumption for carbon sequestration and product production of 5.7 kWhr/m3 CO2 and 1237.8 kWhr/ton Na2CO3, respectively. This coupling design provides a triple-win outcome promoting waste reduction and efficient utilization of resources.