High Production Rate Research Articles

Hollow fiber gas-diffusion electrodes with tailored crystal facets for tuning syngas production in electrochemical CO2 reduction

Electrochemical reduction of CO2 (CO2RR) in aqueous electrolytes not only relies on advanced gas diffusion electrodes (GDEs) to improve CO2 mass transportation but also efficient electrocatalysts to produce specific products. Herein, to produce syngas (CO and H2 mixture), a facet-orientated zinc nanosheet catalyst was electrodeposited on the Cu hollow fiber GDE via a controllable facile surfactant-assisted method. The introduction of cationic surfactant cetyl trimethyl ammonium bromide (CTAB) could manipulate the nucleation and crystal growth of zinc ions around the GDE during the electrodeposition process, leading to controlled changes in the surface free energy and tuned zinc crystal growth orientation. Consequently, the ZncNS-HF with the largest ratio of Zn (101)/Zn (002), resulted in a high current density of 73.3 mA/cm2 and a high syngas production rate of 1328.6 µmol/h∙cm2 at applied potential −1.3 V (vs. RHE). This comes from the hierarchical structure of HFGDE, which provides sufficient CO2 reaching the catalyst/electrolyte interface, and the well-connected zinc nanosheets contribute to a significant number of active sites for CO2RR. This is the first time to configure flow-through or gas-penetrated HFGDEs with zinc crystal facets controlled nanosheet catalysts for syngas production. This research demonstrates the high potential of nanoengineering catalysts for HFGDEs to achieve high production rates of syngas.

Enhanced high β-carotene yeast cell production by Rhodotorula paludigena CM33 and in vitro digestibility in aquatic animals

This study assessed Rhodotorula paludigena CM33's growth and β-carotene production in a 22-L bioreactor for potential use as an aquatic animal feed supplement. Optimizing the feed medium's micronutrient concentration for high-cell-density fed-batch cultivation using glucose as the carbon source yielded biomass of 89.84 g/L and β-carotene concentration of 251.64 mg/L. Notably, using sucrose as the carbon source in feed medium outperforms glucose feeds, resulting in a β-carotene concentration of 285.00 mg/L with a similar biomass of 87.78 g/L. In the fed-batch fermentation using Sucrose Feed Medium, R. paludigena CM33 exhibited high biomass production rates (Qx) of 0.91 g/L.h and remarkable β-carotene production rates (Qp) of 2.97 mg/L.h. In vitro digestibility assays showed that R. paludigena CM33, especially when cultivated using sucrose, enhances protein digestibility affirming its suitability as an aquatic feed supplement. Furthermore, R. paludigena CM33's nutrient-rich profile and probiotic potential make it an attractive option for aquatic nutrition. This research highlights the importance of cost-effective carbon sources in large-scale β-carotene production for aquatic animal nutrition.

In-situ radiogenic heat production in the Cenozoic sediments of the North sea

Radioactive decay is a significant heat source in sedimentary basins. Spectral gamma ray logs from the North Sea well 1/2-2 were used to obtain the uranium, thorium and potassium concentrations in the Cenozoic sediments beneath the well. On average, the sediments contain 1.86 ± 0.37% potassium, 10.12 ± 2.55 ppm thorium and 2.74 ± 1.54 ppm uranium. Abnormally high, up to 8 ppm, uranium concentrations were measured in the transition zones between the Nordland and the Hordaland Group and in the Sele Formation of the Rogaland Group.The estimated heat production rate, of all in-situ radioactive isotopes, is, on average, 1.281 ± 0.35 μW/m3. About 12% (0.143 ± 0.31 μW/m3) can be contributed to potassium, 46% (0.570 ± 0.14 μW/m3) to thorium and 42% (0.567 ± 0.31 μW/m3) to uranium. The estimated radiogenic heat rates vary significantly across the main stratigraphic units. On average, radiogenic heat production is more intensive in shale-dominated material (1.33 ± 0.31 μW/m3) than in sand-rich sediments (0.84 ± 0.36 μW/m3). High heat production rates are very closely related to high uranium concentration. In the “hottest” (2.012 ± 0.27 μW/m3) unit, the Sele Formation, the uranium accounts for about 69% of the generated heat, while the thorium and the potassium contribute with 24% and less than 7%, respectively. In the ”coldest” (0.782 ± 0.35 μW/m3) unit, the Forties, the relative contribution of uranium is only about 36% and that of potassium and thorium are about 18% and 46%, respectively.The radiogenic heat rates in the Cenozoic sediments should be integrated in future evaluations of the geothermal potential in the North Sea.

Exploration history of the igneous reservoirs of the Rio Grande Valley (Mendoza), Neuquén Basin (Argentina)

Abstract Oil seeps related to igneous rocks in the Neuquén Basin have been known since pre-Hispanic times (sixteenth century) and have been explored in the southern Mendoza province since the late nineteenth century. In the 1980s, YPF (Yacimientos Petrolíferos Fiscales) began the exploration of igneous rocks as hydrocarbon reservoirs in the Río Grande Valley area. The possible productivity of these ‘unconventional’ reservoirs was recognized by studying outcrops and well data of sills and dykes emplaced in different formations of the fold and thrust belt of the northern Neuquén Basin. Mud-logging control and evaluations with drill stem tests (DST) were decisive to define these reservoirs as prospective. From petrographical reports on samples from outcrops and cores, six lithological types could be distinguished in the igneous units of this region. Recent works confirm that this volcanism belongs to two predominant cycles: from the late Oligocene to the Miocene (‘Molle’) and from the Middle to upper Miocene (‘Huincán’). Although in igneous reservoirs it is difficult to forecast the estimated ultimate recovery (EUR), sills that crosscut the source rocks of the Vaca Muerta and Agrio formations demonstrate surprisingly high production rates, although the number of wells for the complete development is always difficult to establish.

Multi-vacancy synergistic effect in a NiSe0.4S1.6/ZnO heterostructure for promoting photocatalytic hydrogen production

Defect engineering is one of the methods to improve catalytic activity of photocatalysts, but there are few reports on multi-vacancy systems. In this paper, S doping NiSe2 (NiSe0.4S1.6, NSS) was synthesized and further the NSS/xZnO heterostructures containing Ni, Se and O vacancies were constructed. The hydrogen and active oxygen ions are in situ generated at oxygen vacancy (VO) in ZnO, which greatly reduce the recombination of photocarriers, and the generated active oxygen ions and sacrificial agent anions (S2−, SO32−) involve in the regeneration of oxygen vacancy, which may be one of the reasons for the high activity and stability of the composite catalysts. The polarization electric field is formed by regulating the selenium and nickel double vacancy (VSe, VNi) generated by doping NiSe2 with S, which further improves the charge separation leading to the promotion of photocatalytic hydrogen production. The synergistic effect of the three types of vacancies and the redox properties of the composite catalyst lead to a high H2 production rate of 17.04 mmol·g−1·h−1, 54 and 76 times higher than NSS and ZnO, and a high apparent quantum yield of 15.30 % at 400 nm. The hydrogen production mechanism was explored by EPR, Mott-Schottky, VB-XPS, in suit XPS, DFT, etc. This work proves that the combination of transition metal oxides with rich oxygen defects and metal chalcogenides with metal and chalcogen di-vacancies containing local polarized electric fields is an effective strategy to design high active photocatalyts for water splitting.

Active microbial communities facilitate carbon turnover in brine pools found in the deep Southeastern Mediterranean Sea

Discharge of gas-rich brines fuels productive chemosynthetic ecosystems in the deep sea. In these salty, methanic and sulfidic brines, microbial communities adapt to specific niches along the physicochemical gradients. However, the molecular mechanisms that underpin these adaptations are not fully known. Using metagenomics, we investigated the dense (∼106 cell ml−1) microbial communities that occupy small deep-sea brine pools found in the Southeastern Mediterranean Sea (1150 m water depth, ∼22 °C, ∼60 PSU salinity, sulfide, methane, ammonia reaching millimolar levels, and oxygen usually depleted), reaching high productivity rates of 685 μg C L−1 d−1 ex-situ. We curated 266 metagenome-assembled genomes of bacteria and archaea from the several pools and adjacent sediment-water interface, highlighting the dominance of a single Sulfurimonas, which likely fuels its autotrophy using sulfide oxidation or inorganic sulfur disproportionation. This lineage may be dominant in its niche due to genome streamlining, limiting its metabolic repertoire, particularly by using a single variant of sulfide: quinone oxidoreductase. These primary producers co-exist with ANME-2c archaea that catalyze the anaerobic oxidation of methane. Other lineages can degrade the necromass aerobically (Halomonas and Alcanivorax), or anaerobically through fermentation of macromolecules (e.g., Caldatribacteriota, Bipolaricaulia, Chloroflexota, etc). These low-abundance organisms likely support the autotrophs, providing energy-rich H2, and vital organics such as vitamin B12.

Photocatalytic Hydrogen Peroxide Production through Functionalized Semiconductive Metal-Organic Frameworks.

Hydrogen peroxide (H2O2) holds significance as a vital chemical with the potential to serve as an energy carrier. Compared with the conventional anthraquinone process, photocatalytic H2O2 production has emerged as an appealing alternative because of its energy efficiency and environmental sustainability. However, the existing photocatalysts suffer from low catalytic efficiency, limited tunability of optical properties, and reliance on sacrificial agents due to high energy loss caused by inefficient charge separation. Therefore, developing catalysts with tunable optical properties and efficient charge separation is desirable. In this work, we introduce postsynthetic functionalization into an electrically conductive metal-organic framework, namely, DPT-MOF. Leveraging DPT (3,6-di(4-pyridyl)-1,2,4,5-tetrazine) as a pillar ligand, we exploited click-type chemistry to manipulate band position and charge separation efficiency, allowing for photocatalytic nonsacrificial H2O2 production. Notably, the fluorine-functionalized MOF exhibited the highest H2O2 production rate of 1676 μmol g-1 h-1 under visible light in O2-saturated water among our other samples. This high production rate is attributed to the tuned electronic structure and prolonged charge lifetime facilitated by the fluorine groups. This work highlights the effectiveness of postsynthetic methodology in tuning optical properties, opening a promising avenue for advancing the field of semiconductive MOF-based photocatalysis.

Sustainable composite manufacturing from non-expiring carbon fiber/epoxy prepregs based on a vitrimeric matrix

Despite the benefits of manufacturing composite materials from prepregs, its use is nowadays limited to high-production rate industries due to the high costs associated with their limited shelf life. Once this time passes, the material is considered as expired and disposed of as a non-usable waste. To avoid shortening its shelf life, prepregs are stored in refrigerators, increasing energy consumption, and thus magnifying the negative environmental impact. For this reason, the objective of this paper is to develop a new lifelong prepreg material without an expiration date that can be consolidated as a laminate after surpassing the gelation time of the resin, thus allowing composite materials processing technology based on prepregs without the need of freeze storage. To prove this concept, the study is carried out using a vitrimeric resin composed of an epoxy monomer (DGEBA) and 2-Aminophenyl disulfide (AFD) as a hardener. Two prepregs are manufactured and stored for 30 days at different conditions: environmental conditions, considered as the aged or non-conventional prepreg; and at −18 °C in a freezer, to replicate the conventional prepreg conditions. The results of the cured composites show stable glass transition temperatures and curing degrees between the two laminates. Concerning the mechanical properties, it has been proved that the gelation phenomenon of the non-conventional prepreg does not have any negative effect, showing a 11 % and a 21 % improvement of the flexural strength and failure strain, respectively, together with a 10 % increase of the interlaminar shear strength (ILSS) in comparison with the conventional prepreg, proving the potential of the proposed sustainable prepregs.

Numerical modeling of senile plaque development under conditions of limited diffusivity of amyloid-β monomers

This paper introduces a new model to simulate the progression of senile plaques, focusing on scenarios where concentrations of amyloid beta (Aβ) monomers and aggregates vary between neurons. Extracellular variations in these concentrations may arise due to limited diffusivity of Aβ monomers and a high rate of Aβ monomer production at lipid membranes, requiring a substantial concentration gradient for diffusion-driven transport of Aβ monomers. The dimensionless formulation of the model is presented, which identifies four key dimensionless parameters governing the solutions for Aβ monomer and aggregate concentrations, as well as the radius of a growing Aβ plaque within the control volume. These parameters include the dimensionless diffusivity of Aβ monomers, the dimensionless rate of Aβ monomer production, and the dimensionless half-lives of Aβ monomers and aggregates. A dimensionless parameter is then introduced to evaluate the validity of the lumped capacitance approximation. An approximate solution is derived for the scenario involving large diffusivity of Aβ monomers and dysfunctional protein degradation machinery, resulting in infinitely long half-lives for Aβ monomers and aggregates. In this scenario, the concentrations of Aβ aggregates and the radius of the Aβ plaque depend solely on a single dimensionless parameter that characterizes the rate of Aβ monomer production. According to the approximate solution, the concentration of Aβ aggregates is linearly dependent on the rate of monomer production, and the radius of an Aβ plaque is directly proportional to the cube root of the rate of monomer production. However, when departing from the conditions of the approximate solution (e.g., finite half-lives), the concentrations of Aβ monomers and aggregates, along with the plaque radius, exhibit complex dependencies on all four dimensionless parameters. For instance, under physiological half-life conditions, the plaque radius reaches a maximum value and stabilizes thereafter.

Importance of microzooplankton for sustaining high mesozooplankton biomass during post-bloom period in the Oyashio region of the western subarctic Pacific

We investigated the plankton community structure and biomass during the post-bloom season in the Oyashio region of the western subarctic Pacific, including pico-, nano-, microplankton and mesozooplankton. We found that the nitrate, phosphate and silicic acid concentrations remained high at >4.2 μM, >0.77 μM and >7.1 μM, respectively, in the euphotic layer at almost all sampling stations, but that the chlorophyll a concentrations were low (<3 µg Chl. a l−1). These findings indicate high nutrient and low chlorophyll (HNLC)-like conditions. In the phytoplankton community, pennate diatoms, the larger subpopulation of pico-sized eukaryotic phytoplankton, and nano-flagellates substantially contributed to the low biomass of the chain-forming centric diatoms that mainly comprised the spring phytoplankton bloom. The microzooplankton biomass was 2.7–4.4 fold greater than the phytoplankton biomass in the surface layer. Naked ciliates substantially contributed to the microzooplankton community (40–87 %). The naked ciliate growth rates during our in situ bottle incubation experiments were significantly greater than the maximum growth rates as calculated from cell volume and water temperature. The mesozooplankton biomass was mainly composed of krill and copepods and was 5.9–9.3 fold higher than the microzooplankton biomass. This inverted biomass pyramid with relatively low microzooplankton and high mesozooplankton biomass may be explained by the high production and growth rates of the microzooplankton. The ratio of phytoplankton growth (µ, d−1) to grazing mortality (m, d−1) by microzooplankton were relatively low at 0.26–0.44 m/µ in our dilution experiments. These low values indicate that microzooplankton grazing does not regulate phytoplankton growth and suggests that microzooplankton feed on an alternative nutritional source, such as heterotrophic prey items, or mixotrophy to fulfill their growth needs. Additional research is needed during the post-bloom period to further evaluate the mechanisms that sustain microzooplankton dominance and production in the Oyashio region under the HNLC-like conditions, especially for naked ciliates.

Structural complexity and benthic metabolism: resolving the links between carbon cycling and biodiversity in restored seagrass meadows

Abstract. Due to large losses of seagrass meadows worldwide, restoration is proposed as a key strategy for increasing coastal resilience and recovery. The emergence of a seagrass meadow is expected to substantially amplify biodiversity and enhance benthic metabolism by increasing primary productivity and respiration. Nevertheless, open questions remain regarding the metabolic balance of aging seagrass meadows and the roles benthic communities within the seagrass ecosystem play in overall metabolism. To address these questions, we investigated a chronosequence of bare sediments and adjacent Zostera marina meadows of 3 and 7 years since restoration alongside a natural meadow located within a high-temperate marine embayment in Gåsö, Sweden. We combined continuous measurements of O2 fluxes using underwater eddy covariance with dissolved inorganic carbon (DIC) and O2 fluxes from benthic chambers during the productive season (July). Based on the ratio between O2 and DIC, we derived site-specific photosynthetic and respiratory quotients, enabling the conversion of eddy covariance fluxes to DIC. We assessed benthic diversity parameters as potential drivers of metabolic flux variability. We observed high rates of gross primary productivity (GPP) spanning −18 to −82 mmolDICm-2d-1, which increased progressively with meadow age. Community respiration (CR) mirrored the GPP trend, and all meadows were net heterotrophic (GPP &lt; CR), with net community productivity (NCP) ranging from 16 to 28 mmolDICm-2d-1. While autotrophic biomass did not increase with meadow age, macrophyte diversity did, elucidating potential effects of niche complementarity among macrophytes on community metabolism. These findings provide valuable insights into how community composition and meadow development relate to ecosystem functioning, highlighting potential tradeoffs between carbon uptake and biodiversity.

Biochemical dynamics during postharvest: Highlighting the interplay of stress during storage and maturation of fresh produce.

The lifecycle of fresh produce involves a sequence of biochemical events during their ontology, and these events are particularly significant for climacteric fruits. A high demand during ripening is observed in these plant products, which is reflected in a high rate of respiration and ethylene production. Increased respiratory demand triggers the activation of secondary pathways such as alternate oxidase, which do not experience critical increases in energy consumption in non-climacteric fruit. In addition, biochemical events produced by external factors lead to compensatory responses in fresh produce to counteract the oxidative stress caused by the former. The dynamics of these responses are accompanied by signaling, where reactive oxygen species play a pivotal role in fresh product cell perception. This review aims to describe the protection mechanisms of fresh produce against environmental challenges and how controlled doses of abiotic stressors can be used to improve quality and prolong their shelf-life through the interaction of stress and defense mechanisms.

Modulating the Primary and Secondary Coordination Spheres of Single Ni(II) Sites in Metal-Organic Frameworks for Boosting Photocatalysis.

Though the coordination environment of single metal sites has been recognized to be of great importance in promoting catalysis, the influence of simultaneous precise modulation of primary and secondary coordination spheres on catalysis remains largely unknown. Herein, a series of single Ni(II) sites with altered primary and secondary coordination spheres have been installed onto metal-organic frameworks (MOFs) with UiO-67 skeleton, affording UiO-Ni-X-Y (X = S, O; Y = H, Cl, CF3) with X and Y on the primary and secondary coordination spheres, respectively. Upon deposition with CdS nanoparticles, the resulting composites present high photocatalytic H2 production rates, in which the optimized CdS/UiO-Ni-S-CF3 exhibits an excellent activity of 13.44 mmol g-1, ∼500 folds of the pristine catalyst (29.6 μmol g-1 for CdS/UiO), in 8 h, highlighting the key role of microenvironment modulation around Ni sites. Charge kinetic analysis and theoretical calculation results demonstrate that the charge transfer dynamics and reaction energy barrier are closely correlated with their coordination spheres. This work manifests the advantages of MOFs in the fabrication of structurally precise catalysts and the elucidation of particular influences of microenvironment modulation around single metal sites on the catalytic performance.

Hollow carbon sphere featuring highly dispersed Co-Nx sites for efficient and controllable syngas electrosynthesis from CO2

Electrochemical reduction of CO2 and H2O powered by green electricity provides a sustainable way to produce syngas. However, this reaction still suffers from insufficient syngas selectivity, slow charge kinetic process, and poor controllability of the CO/H2 ratio. In this work, we report a hollow carbon sphere electrocatalyst featuring highly dispersed Co-Nx sites (Co-NHCS-x) for efficient and controllable syngas electrosynthesis. The Co-NHCS-400 sample exhibits a high syngas production rate with a steady CO/H2 ratio (≈1:2) over a wide range of operating potential from −0.6 V to −1.1 V vs. RHE. The variation in synthesis temperature can finely tune the coordination environment of Co-Nx in the catalyst. Consequently, the adsorption behaviors of the CO and hydrogen atoms can be manipulated, allowing for the precise adjustment of CO and H2 proportions in the product gas. The findings are potentially applicable to the exploitation of promising carbon-based electrocatalysts for electrochemical CO2 conversion into syngas.

Tuning Electrons Migration of Dual S Defects Mediated MoS2-x/ZnIn2S4-x Toward Highly Efficient Photocatalytic Hydrogen Production.

Photocatalytic hydrogen production is a prevalent method for hydrogen synthesis. However, high recombination rate of photogenerated carriers and high activation energy barrier of H remain persistent challenge. Here, the two-step hydrothermal method is utilized to prepare dual S-defect mediated catalyst molybdenum sulfide/zinc indium sulfide (MSv/ZISv), which has high hydrogen production rate of 8.83 mmolg-1h-1 under simulated sunlight. The achieved rate is 21.91 times higher than pure ZnIn2S4 substrate. Defects in ZIS within MSv/ZISv modify the primitive electronic structure by creating defect state that retaining good reducing power, leading to the rapid separation of electron-hole pairs and the generation of additional photogenerated carriers. The internal electric field further enhances the migration toward to cocatalyst. Simultaneously, the defects introduced on the MoS2 cause electron rearrangement, leading to electron clustering on both S vacancies and edge S. Thereby MSv/ZISv exhibits the lowest activation energy barrier and |ΔGH*|. This work explores the division of synergies between different types of S defects, providing new insights into the coupling of defect engineering.

The Effect of Feeding Formula in Honey Bees (Apis mellifera) Using Flow Hive Technology on Honey Production and Quality at PT Kembang Joyo Sriwijaya

Bee feeding has long been known and applied in honey bee farming. One way of feeding bees is to give sugar syrup mixed with water. This study aims to determine the effect of supplementary feeding on bees that have been formulated on the production and quality of honey produced. This study also applies one of the artificial hive technologies, namely flow hive. This study also observed how the adaptation of bees and the added value of the flow hive using Apis mellifera honey bees which is known for its high production rate and high adaptability. This research was conducted from September to December 2023 at PT Kembang Joyo Sriwijaya, Malang Regency. The experiment was conducted using 3 flow hives with the same feed formula. The study showed good feed consumption in stup 1 and decreased feed consumption in stup 2 and stup 3. Honey obtained in stup 1 was 1.5 kg from 1 flow frame. Laboratory test results showed pH levels of 3.4, moisture content of 18.2 %, reducing sugar levels of 55.44 % and 56.71 % and diastase enzyme activity of 3.18 DN and 3.19 DN. In conclusion that formula feeding did not show high honey production when compared to the time taken to reach harvest and also did not show fulfilling reducing sugar content and diastase enzyme activity test results.

In Situ Synthesis of CuxO/N Doped Graphdiyne with Pyridine N Configuration for Ammonia Production via Nitrate Reduction.

Electroreduction of nitrate to ammonia provides an interesting pathway for wastewater treatment and valorization. Cu-based catalysts are active for the conversion of NO3 - to NO2 - but suffer from an inefficient hydrogenation process of NO2 -. Herein, CuxO/N-doped graphdiyne (CuxO/N-GDY) with pyridine N configuration are in situ prepared in one pot. Benefiting from the synergistic effect of pyridinic N in GDY and CuxO, the prepared CuxO/N-GDY tested in a commercial H-cell achieved a faradaic efficiency of 85% toward NH3 at -0.5V versus RHE with a production rate of 340µmolh-1mgcat -1 in 0.1M KNO3. When integrating the CuxO/N-GDY in an anion exchange membrane flow electrolyzer, a maximum Faradaic efficiency of 89% is achieved at a voltage of 2.3V and the production rate is 1680µmol h-1mgcat -1 at 3.3V in 0.1M KNO3 at room temperature. Operation at 40°C further promoted the overall reaction kinetics of NO3 - to NH3, but penalized its selectivity with respect to hydrogen evolution reaction. The high selectivity and production rate in this device configuration demonstrate its potential for industrial application.

N-coordinated Ag sites on ordered mesoporous carbons for highly efficient electrolytic production of H2O2 in acidic electrolyte

N-coordinated Ag (Ag-Nx) sites embedded in ordered mesoporous carbon (Ag-Nx/C) were prepared by pyrolyzation of Ag-2, 2-bipyridine complexes in the confined channels of mesoporous SBA-15 silica. This nanocasting method allowed high dispersion state of Ag-Nx sites on carbons with ordered mesoporous channels and higher specific surface area. Ag-Nx/C was found to be very active electrocatalyst for two-electron oxygen reduction reaction (2e- ORR) in 0.1 M HClO4 acidic electrolyte. The bulk electrolytic production for hydrogen peroxides (H2O2) could be achieved with a high production rate of 1.67 mol h−1 gcat−1 together with high electrolysis Faraday efficiency of about 93%. Ag-Nx/C also revealed better acid-resistant durability during H2O2 electrolysis production. This work provided an efficient and durable Ag-Nx/C electrocatalyst for electrolytic H2O2 production in acids.

Optimizing a twin-chamber system for direct ozone production rate measurement

High Ozone Production Rate (OPR) leads to O3 pollution episodes and adverse human health outcomes. OPR observation (Obs-OPR) and OPR modelling (Mod-OPR) have been obtained from observed and modelled peroxy radicals and nitrogen oxides. However, discrepancies between them remind of an imperfect understanding of O3 photochemistry. Direct measurement of OPR (Mea-OPR) by a twin-chamber system emerges. Herein, we optimized Mea-OPR design, i.e., minimizing the chamber surface area to volume ratio (S/V) to 9.8 m−1 from 18 m−1 and the dark uptake coefficient of O3 to 9.9 × 10−9 from 7.1 × 10−8 in the literature. In addition, control experiments further revealed and quantified a photo-enhanced O3 uptake, and therefore recommended an essential correction of Mea-OPR. We finally characterized a measurement uncertainty of ±38% and a detection limit of 3.2 ppbv h−1 (3SD), which suggested that Mea-OPR would be sensitive enough to measure OPR in urban or suburban environments. Further application of this system in urban Beijing during the Beijing 2022 Olympic Winter Games recorded a noontime OPR of 7.3 (±3.3, 1SD) ppbv h−1. These observational results added up to our confidence in future field application of Mea-OPR, to facilitate pollution control policy evaluation and to shed light on O3 photochemistry puzzle.

Gas production from a promising reservoir of the hydrate with associated and shallow gas layers in the low permeable sediments

The gas production rate from hydrate trials is still below commercial criterion. To increase the production rate, a promising geological system consisting of hydrate, associated and shallow gas layers was explored recently. Herein, the gas production of this complex geological system through depressurization was numerically investigated. The result showed a high gas production rate in the first tens day, and a subsequently slow decrease with an increasing water production rate under the immediate depressurization condition. The free gas layer contributed the most of gas production while the least is from hydrate reservoir. For water production, the most was from the associated gas layer and a moderate from hydrate layer. Among all factors, the depressurization rate affected greatly the initial gas rate, and slight depressurization caused a high and stable rate. The permeability, gas saturation and irreducible water saturation of the shallow gas layer affected dramatically the gas rate and obviously the corresponding water rate. Special attention should be paid to the hydrate forming in the shallow gas layer. This hydrate barrier caused a decrease of gas rate when reducing production pressure. The production of the complex system enhances the economic benefit, and it becomes a prospective system of exploration.