Search Results (110)

In the summer of 2022, central and eastern China experienced prolonged extreme high temperatures and severe drought, leading to significant economic losses. To gain a more profound understanding of this drought event and furnish a reference for forecasting similar events in the future, this study examines the circulation anomalies associated with the drought. Employing a diagnostic method focused on temperature and moisture anomalies, this study introduces a novel approach to quantify and compare the relative significance of moisture transport and warm air dynamics in contributing to the drought. This study examines the atmospheric circulation anomalies linked to the drought event and compares the relative contributions of water vapor transport and warm air activity in causing the drought, using two parameters defined in the paper. The results show the following: (1) The West Pacific Subtropical High (WPSH) was more intense than usual and extended westward, consistently controlling the Yangtze River Basin. Simultaneously, the polar vortex area was smaller and weaker, the South Asian High area was larger and stronger, and it shifted eastward. These factors collectively led to weakened water vapor transport conditions and prevailing subsiding air motions in the Yangtze River Basin, causing frequent high temperatures. (2) By defining I_q and I_t to represent the contributions of moisture and temperature to precipitation, we found that the drought event in the Yangtze River Basin was driven by both reduced moisture supplies in the lower troposphere and higher-than-normal temperatures, with temperature playing a dominant role. Full article

The shortage of freshwater resources has become the core bottleneck of global sustainable development. Traditional freshwater harvesting technologies are restricted by geographical conditions and environmental limitations, making them increasingly difficult to satisfy the growing water demand. In this study, based on the synergistic coupling mechanism of photothermal conversion and radiative cooling, a solar auto-tracking assisted selective solar absorber and radiative cooling all-weather freshwater harvesting device was innovatively developed. The prepared selective solar absorber achieved a high absorptivity of 0.91 in the solar spectrum (0.3–2.5 μm) and maintained a low emissivity of 0.12 in the mid-infrared range (2.5–20 μm), significantly enhancing the photothermal conversion efficiency. The radiative cooling film demonstrated an average cooling effect of 7.62 °C during typical daytime hours (12:00–13:00) and 7.03 °C at night (22:00–23:00), providing a stable low-temperature environment for water vapor condensation. The experimental results showed that the experimental group equipped with the solar auto-tracking system collected 0.79 kg m⁻² of freshwater in 24 h, representing a 23.4% increase compared to the control group without the solar auto-tracking system. By combining theoretical analysis with experimental validation, this study presents technical and economic advantages for emergency water and island freshwater supply, offering an innovative solution to mitigate the global freshwater crisis. Full article

Microbial contamination and biofilm formation on food contact materials (FCMs) represent critical challenges within the food supply chain, compromising food safety and quality while increasing the risk of foodborne illnesses. Traditional materials often lack sufficient microbial resistance to contamination, creating a high demand for innovative antimicrobial surfaces. This study assessed the effectiveness of a nanosized deposited SiO_xC_yH_z coating approved for food contact on 3D-printed polyamide 12 (PA12) disk substrates, aiming at providing antimicrobial and anti-biofilm functionality to mechanical components and packaging material in the food supply chain. The coating was applied using plasma-enhanced chemical vapor deposition (PECVD) and characterized through Fourier-transform infrared spectroscopy (FTIR), Raman spectroscopy, thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and contact angle measurements. Coated PA12 samples exhibited significantly enhanced hydrophobicity, with an average water contact angle of 112.9°, thus improving antibacterial performance by markedly reducing bacterial adhesion. Microbiological assays revealed a significant (p < 0.001) bactericidal activity (up to 4 logarithms after 4 h, ≥99.99%) against Gram-positive and Gram-negative bacteria, including notable foodborne pathogens such as L. monocytogenes, S. aureus, E. coli, and S. typhimurium. SiO_xC_yH_z-coated PA12 surfaces exhibited strong antibacterial activity, representing a promising approach for coating additive-manufactured components and equipment for packaging production in the food and pharmaceutical supply chain able to enhance safety, extend product shelf life, and reduce reliance on chemical sanitizers. Full article

Multilayer clouds, comprising vertically stacked cloud layers with distinct microphysical characteristics, constitute a critical yet complex atmospheric phenomenon influencing regional to global climate patterns. Advances in observational techniques, particularly the application of high-resolution humidity vertical profiling via radiosondes, have significantly enhanced multilayer cloud detection capabilities. Multilayer clouds are widely distributed around the world, showing significant regional differences. Many studies have been carried out on the formation mechanism of multilayer clouds, and observational evidence indicates a close relationship between multilayer cloud development and water vapor supply, updraft, atmospheric circulation, as well as wind shear; however, a unified and comprehensive theoretical framework has not yet been constructed to fully explain the underlying mechanism. In addition, the unique vertical structure of multilayer clouds exhibits different climate effects when compared with single-layer clouds, affecting global climate patterns by regulating precipitation processes and radiative energy budgets. This article reviews the research progress related to multilayer cloud observations and their climate effects and looks forward to the research that needs to be carried out in the future. Full article

Midlatitude westerly and East Asian summer monsoon (EASM) are crucial circulation systems in the upper and lower troposphere of East Asia that significantly influence mid-summer precipitation pattern. However, their synergistic effect on mid-summer precipitation in North China (NC) remains unclear. In this study, the concurrent variations of mid-summer westerly and EASM are categorized into two configurations: strong westerly–strong EASM (SS) and weak westerly–weak EASM (WW). At the synoptic timescale, the SS configuration significantly enhances precipitation in NC, whereas the WW configuration suppresses mid-summer rainfall. The underlying mechanism is that the SS pattern stimulates an anomalous quasi-barotropic cyclone–anticyclone pair over the Mongolian Plateau–Yellow Sea region. Two anomalous water vapor channels (westerly-driven and EASM-driven water vapor transport) are established in the southern and western peripheries of this cyclone–anticyclone pair, ensuring abundant moisture supply over NC. Meanwhile, frequently occurring westerly jet cores in northern NC form a jet entrance region, favoring strong upper-level divergent pumping and deep accents in its southern flank. This synergy between strong westerlies and EASM enhances both the moisture transports and ascending movements, thereby increasing precipitation over NC. Conversely, the atmospheric circulation associated with the WW pattern exhibits opposite characteristics, resulting in decreased NC rainfall. Our findings elucidate the synoptic-scale influences of westerly–monsoon synergy on mid-summer rainfall, through regulating moisture transports and westerly jet-induced dynamic uplift, potentially improving predictive capabilities for mid-summer precipitation forecasting. Full article

In this experiment, NiCo₂O_x catalysts, with different elements added (Mg, Fe, Cu, and Ce), were prepared using the co-precipitation method to investigate their catalytic performance for carbon monoxide, as well as their water resistance and sulfur resistance. Combined with the sintering flue gas environment of Baosteel Zhanjiang Iron and Steel Co., Ltd., it provides a reference for the catalytic oxidation of CO in complex environments. The results reveal that the Fe-added catalysts exhibited a better CO catalytic performance and possessed good redox properties, and the Fe metal ion-added NiCo₂O_x catalysts showed a CO catalytic efficiency of 91.72% at 100 °C. Meanwhile, the Fe-added catalysts had the strongest resistance to water, with a conversion of 98.37% to CO at 140 °C, and with 10% water vapor. The Ce-added catalyst showed a better SO₂ resistance and hybrid resistance of SO₂ and H₂O. Under the condition of sulfur addition, the CO conversion of the Ce-added catalyst was as high as 63.07% after 4 h of SO₂ introduction, and the efficiency could be restored to 100% after cutting off the supply of SO₂. Under the conditions of sulfur addition and water addition, the CO conversion of the catalyst was 98.23% after cutting off the SO₂. Full article

The water adsorption property was shown to be the critical process limiting the thermal output in the adsorption heat storage driven by the air humidity process, which was different for the physical adsorbent and the physical/chemical adsorbent. In this study, coconut shell-based activated carbon (CAC), a hierarchically porous material that is both low-cost and mass-producible, was utilized as a physical adsorbent and as a matrix for loading calcium chloride (CAC/Ca). The incorporation of calcium chloride in CAC, with a 24% content, resulted in a 4~102% increase in water uptake capacity. The water uptake dynamics of high-thickness adsorbents are inhibited, especially for CAC/Ca. In the context of the adsorption test conducted within a fixed-bed reactor, an increase in air velocity was observed to facilitate water vapor supply, thereby culminating in higher output temperatures for both CAC and CAC/Ca, indicating a higher hydration conversion. The maximum discharge powers of CAC/Ca increased from 2 kW/m³ to 20 kW/m³, with the air velocity increasing from 0.5 m/s to 2.5 m/s. The heat-release densities of CAC and CAC/Ca at the air velocity of 2.5 m/s were 156 kJ/kg and 547 kJ/kg, respectively. Full article

Due to urban expansion and limited heat sources, the heating capacity of heat supply stations is inadequate to meet the growing heat demand. In current heat supply stations, heat from the primary heat network is generally conveyed to the secondary heat network solely via plate heat exchangers, resulting in the return water temperature of the primary heat network being as high as 50 °C, with a substantial amount of recoverable waste heat resources. In this paper, a case study of a heat supply station with insufficient heating capacity in Beijing is conducted to propose supplemental heating systems using vapor-compression heat pumps and absorption heat pumps to further extract waste heat from the primary heat network. Through the TRNSYS platform, simulation models for both systems were developed. Then, based on the bilevel optimization method, the design scheme and operational strategy were co-optimized with the objective of minimizing the lifecycle cost. The performance of the two systems was compared from the perspectives of energy consumption, economy, additional footprint, and regional applicability. The results indicate that the energy consumption of the vapor-compression heat pump supplemental heating system (VCSHS) is 0.85% higher than that of the absorption heat pump supplemental heating system (ASHS), with supplementary heat of 3500 kW. The initial cost of the VCSHS is approximately 1 million CNY lower than that of the ASHS, while the operational costs of both systems are nearly identical, making the VCSHS more cost-effective overall. Additionally, the footprint of new equipment in the VCSHS is nearly 30% smaller than that in the ASHS. Compared with cold regions, it is more economical to adopt ASHSs in severe cold regions due to their lower heat price. Full article

Aspergillus spp. and their produced aflatoxins are responsible for contaminating 25–30% of the global food supply, including many grains, and nuts which when consumed are detrimental to human and animal health. Despite regulatory frameworks, Aspergillus spp. and aflatoxin contamination is still a global challenge, especially in cereal-based matrices and their derived by-products. The methods for reducing Aspergillus spp. and aflatoxin contamination involve various approaches, including physical, chemical, and biological control strategies. Recently, a novel technology, atmospheric cold plasma (ACP), has emerged which can reduce mold populations and also degrade these toxins. ACP is a non-thermal technology that operates at room temperature and atmospheric pressure. It can reduce mold and toxins from grains and seeds without affecting food quality or leaving any chemical residue. ACP is the conversion of a gas, such as air, into a reactive gas. Specifically, an electrical charge is applied to the “working” gas (air) leading to the breakdown of diatomic oxygen, diatomic nitrogen, and water vapor into a mixture of radicals (e.g., atomic oxygen, atomic nitrogen, atomic hydrogen, hydroxyls), metastable species, and ions (e.g., nitrate, nitrite, peroxynitrate). In a cold plasma process, approximately 5% or less of the working gas is ionized. However, cold plasma treatment can generate over 1000 ppm of reactive gas species (RGS). The final result is a range of bactericidal and fungicidal molecules such as ozone, peroxides, nitrates, and many others. This review provides an overview of the mechanisms and chemistry of ACP and its application in inactivating Aspergillus spp. and degrading aflatoxins, serving as a novel treatment to enhance the safety and quality of grains and nuts. The final section of the review discusses the commercialization status of ACP treatment. Full article

More efficient systems and renewable energies are determinants of reducing the negative impact on the environment. A novel cogeneration system is modeled for the simultaneous production of power and cooling driven by geothermal energy utilizing an ammonia–water mixture. The system can be used in rural communities by using renewable energies or in industries where waste heat is available. The system is a modification of a Goswami cycle in which a separator has been added to produce an extra amount of ammonia vapor to increase the cooling effect. Energy and exergy analyses are conducted as a function of the main operating temperatures. From the optimization, it is found that the maximum energy utilization factor is 0.54, and the exergy efficiency is 0.37, producing 81.45 kW of power and 1068 kW of cooling. A case study is also conducted for a rural community located in the estate of Jalisco, México. The proposed system is capable of preserving 3750 L of milk/day while simultaneously producing 12.53 kW of power when 230.6 kW of geothermal energy is supplied at 120 °C. Full article

It is anticipated that global warming will modify precipitation and evapotranspiration patterns, consequently affecting water availability. Changes in water availability pose challenges to freshwater supply, food security, and ecosystem sustainability. However, the variations and driving mechanisms of water availability in the arid and semiarid regions of Northern China remain unclear. This study evaluates the accuracy of three evapotranspiration products and analyzes the changes in water availability in the arid and semiarid regions of Northern China over the past 39 years (1982–2020) along with their driving factors. The results indicate that during this period, precipitation increased at a rate of 7.5 mm/decade, while evapotranspiration rose at a higher rate of 13 mm/decade, resulting in a decline in water availability of 5.5 mm/decade. Spatially, approximately 30.17% of the area exhibited a significant downward trend in water availability, while 65.65% remained relatively stable. Evapotranspiration is the dominant factor leading to the decrease in water availability, with a contribution rate of 63.41%. The increase in evapotranspiration was primarily driven by temperature (32.53% contribution) and the saturation vapor pressure deficit (24.72% contribution). The decline in water availability may further exacerbate drought risks in arid and semiarid regions. The research results can provide a scientific basis for developing water resource management strategies and ecological restoration strategies under environmental change. Full article

Based on statistical analyses of long-term reanalysis data, we have investigated the interdecadal variations of autumn precipitation in central China (APC-d) and the associated atmospheric teleconnection. It reveals that the increased autumn rainfall in central China during the last decade is a portion of the APC-d, which exhibits a high correlation coefficient of 0.7 with the interdecadal variations of the Europe–China pattern (EC-d pattern) teleconnection. The EC-d pattern teleconnection presents in a “+-+” structure over Eurasia, putting central China into the periphery of a quasi-barotropic anticyclonic high-pressure anomaly. Driven by positive vorticity advection and the inflow of warmer and moist air from the south, central China experiences enhanced ascending motion and abundant water vapor supply, resulting in increased rainfall. Further analysis suggests that the EC-d pattern originates from the exit of the North Atlantic jet and propagates eastward. It is captured by the Asian westerly jet stream and proceeds towards East Asia through the wave–mean flow interaction. The wave train acquires effective potential energy from the mean flow by the baroclinic energy conversion and simultaneously obtains kinetic energy from the basic westerly jet zones across the North Atlantic and the East Asian coasts. The interdecadal variation of the mid-latitude North Atlantic sea surface temperature (MAT-d) exhibits a significant negative relationship with EC-d, serving as a modulating factor for the EC-d pattern teleconnection. Experiments with CMIP6 models predict that the interdecadal variations in APC-d, EC-d, and MAT-d will maintain stable high correlations for the rest of the 21st century. These findings may contribute to forecasting the interdecadal autumn dry–wet conditions in central China. Full article

Water vapor transport is an important foundation and prerequisite for the occurrence of rainstorms. Consequently, the understanding of water vapor transport as well as the sources of water vapor during rainstorm processes should be considered as essential to study the formation mechanism of rainstorms. In this study, the Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model is adopted for backward tracking of water vapor transport trajectories and sources during the “7·20” extraordinary heavy rain process in Zhengzhou City of China that occurred on 20 July 2021. On this basis, the trajectory clustering method is applied to quantitatively analyze the contributions of water vapor sources, aiming to provide a basis for exploring the maintenance mechanism of this extreme rainstorm event. The spatio-temporal characteristics of this rainstorm event show that there are 4 consecutive days with the precipitation reaching or exceeding the rainstorm level across the whole Zhengzhou City, with the daily rainfall amounts at eight national meteorological stations all breaking their respective historical extreme values. The regional-averaged rainfall amount in Zhengzhou City is 527.4 mm, while the maximum accumulated rainfall amount reaches 985.2 mm at Xinmi station and the maximum hourly rainfall amount at Zhengzhou national meteorological station reaches 201.9 mm h⁻¹. The water vapor sources for this rainfall process, ranked in descending order of contribution, are the Western Pacific, inland areas of Northwest China and South China, and South China Sea. The water vapor at lower levels is mainly transported from the Western Pacific and the South China Sea, while those from the inland areas of Northwest China and South China provide a supply of water vapor at upper levels to a certain extent. The water vapor at 950 hPa is mainly sourced from the Western Pacific and South China Sea, accounting for 56% and 44%, respectively. The water vapor at 850 hPa mainly derives from the Western Pacific and the inland areas of South China, contributing 58% and 34% of the total, respectively. The water vapor at 700 hPa mainly comes from the inland areas of Northwest China and South China Sea. Specifically, the water vapor from inland Northwest China contributes 44% of the total, acting as the primary source. The water vapor at 500 hPa is mainly transported from the inland areas of South China and Northwest China, with that from the inland South China (56%) being more prominent. The water vapor at all levels is mainly transported to the rainstorm region through the eastern and southern regions of China from the source areas. Additionally, there are some differences in the water vapor trajectories at a 6 h interval. Full article

The analysis of GHG emissions for different sectors shows that one of the main contributions, responsible for 25%, is electricity and heat production. An important aspect of electricity use concerns motor pumps, which are used for both urban water supply and agricultural water systems. Generally, the highest consumption corresponds to summer, when the maximum solar radiation makes the use of solar water pumps possible. However, the total conversion of energy by conventional solar pumps is about 10% of the solar energy. This low efficiency has limited the choice of solar water pumps to areas without alternative power sources. Moreover, the final efficiency will further decrease due to that of other parts of the system, so, in order to achieve higher efficiency and sustainability, a novel method for solar water pumps must be developed. The new solar pump that we propose will take advantage of the efficiency of solar concentration dishes to absorb solar radiation, which is about 80–90%, will pump water using water vapor pressure, and will not need an electrical motor. It will offer several benefits besides high efficiency in pumping water, like the number of mechanical parts required and their maintenance costs, making its application easy and removing the limitations of typical systems. Full article

The carbon source/sink nature and the water balance of a drip-irrigated and mulched watermelon cultivated under a semi-arid climate were investigated. Biodegradable films, plants and some fruits were left on the soil as green manure. The study spanned from watermelon planting to the subsequent crop (June–November 2023). The eddy covariance technique was employed to monitor water vapor (H₂O) and carbon dioxide (CO₂) fluxes, which were partitioned into transpiration, evaporation, photosynthesis and respiration, respectively, using the flux variance similarity method.This method utilizesthe Monin–Obukhov similarity theory to separate stomatal (photosynthesis and transpiration) from non-stomatal (respiration and evaporation) processes. The results indicate that mulching films contribute to carbon sequestration in the soil (+19.3 g C m⁻²). However, the mulched watermelon crop presented in this study functions as a net carbon source, with a net biome exchange, representing the net rate of C accumulation in or loss from ecosystems, equal to +230 g C m⁻². This is primarily due to the substantial amount of carbon exported through marketable fruits. Fixed water scheduling led to water waste through deep percolation (approximately 1/6 of the water supplied), which also contributed to the loss of organic carbon via leaching (−4.3 g C m⁻²). These findings recommend further research to enhance the sustainability of this crop in terms of both water and carbon balances. Full article