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Studies conducted at the beginning of this century revealed a warming and humidification trend in northwest China, which lasted for a short period, with some minor variations. The future trend remains uncertain, with uncertainty over the future duration of warming and humidification trends in the region. In this study, a comprehensive index was constructed to quantitatively characterize the degree of humidity. Using observation data, National Center for Atmospheric Research/National Centers for Environmental Prediction (NCAR/NCEP) reanalysis data, and future scenario prediction data we systematically analyzed the temporal and spatial evolution characteristics of the warming and humidification trend in northwest China and its possible causes. The results showed that the temperature in northwest China has been continuously increasing since 1961, and although there was no obvious precipitation trend from 1961 to 1999, it has been increasing nonlinearly since 2000. The wetness index considers the synergy of evaporation and precipitation, and had the same pattern of variation as precipitation. From a spatial perspective, the temperature has consistently increased throughout the whole northwest region, and the degree of warming has gradually increased. Precipitation displayed a trend of increasing in the west and decreasing in the east, but the area with increased rainfall expanded eastward over almost three climatic periods, and the area experiencing humidification extended across the whole of the northwest. There has been an obvious eastward expansion of climate humidification in northwest China since the start of this century. However, the current extent of climate humidification has not changed the basic climate pattern in northwest China. Over the next 30 years, the humidification trend will likely slow down significantly compared with the last 20 years. The eastward expansion of climate humidification since the start of this century may have resulted from the multi-decadal synergistic influence of westerly wind circulation and monsoon circulation.

PurposeHigh-flow nasal cannula (HFNC) oxygen therapy was noninferior to noninvasive ventilation (NIV) for preventing reintubation in a heterogeneous population at high-risk for extubation failure. However, outcomes might differ in certain subgroups of patients. Thus, we aimed to determine whether NIV with active humidification is superior to HFNC in preventing reintubation in patients with ≥ 4 risk factors (very high risk for extubation failure).MethodsRandomized controlled trial in two intensive care units in Spain (June 2020‒June 2021). Patients ready for planned extubation with ≥ 4 of the following risk factors for reintubation were included: age > 65 years, Acute Physiology and Chronic Health Evaluation II score > 12 on extubation day, body mass index > 30, inadequate secretions management, difficult or prolonged weaning, ≥ 2 comorbidities, acute heart failure indicating mechanical ventilation, moderate-to-severe chronic obstructive pulmonary disease, airway patency problems, prolonged mechanical ventilation, or hypercapnia on finishing the spontaneous breathing trial. Patients were randomized to undergo NIV with active humidification or HFNC for 48 h after extubation. The primary outcome was reintubation rate within 7 days after extubation. Secondary outcomes included postextubation respiratory failure, respiratory infection, sepsis, multiorgan failure, length of stay, mortality, adverse events, and time to reintubation.ResultsOf 182 patients (mean age, 60 [standard deviation (SD), 15] years; 117 [64%] men), 92 received NIV and 90 HFNC. Reintubation was required in 21 (23.3%) patients receiving NIV vs 35 (38.8%) of those receiving HFNC (difference −15.5%; 95% confidence interval (CI) −28.3 to −1%). Hospital length of stay was lower in those patients treated with NIV (20 [12‒36.7] days vs 26.5 [15‒45] days, difference 6.5 [95%CI 0.5–21.1]). No additional differences in the other secondary outcomes were observed.ConclusionsAmong adult critically ill patients at very high-risk for extubation failure, NIV with active humidification was superior to HFNC for preventing reintubation.

RO plants reject water from textile industries in landlocked regions containing high TDS, raising serious environmental concerns. The conventional desalination methods often rely on high-energy inputs based on fossil fuels. To address this concern, solar-assisted humidification dehumidification desalination (SA-HDH) was investigated as one of the promising options. This study investigates the development of a sustainable solar air-heated humidification–dehumidification desalination (HDH) process using a single-ended open evacuated tube collector (SEO-ETC). An experimental evaluation was conducted to assess the system's performance. The key parameters were analyzed, including freshwater production rate, energy efficiency, exergy efficiency, humidification rate, economic analysis, overall CO 2 mitigation, and the impact of solar radiation on performance. The current study was experimentally investigated at different mass flow rate ratios of M f R = 2, 2.5, and 3 by varying air flow rates in open and closed loop configurations. The finding shows a significantly higher humidification rate and freshwater yield in a closed-loop air circulation compared with open-loop mode. Also, it was observed that the increasing air temperature inlet to the humidifier positively impacts the system performance. The results revealed that the system performs better in the optimum value of M f R = 2.5 in a closed-loop configuration. The freshwater yield of 3.12 kg/m 2 -day (8.89 kg/kWh) was obtained at an M f R of 2.5 in closed-loop configurations. The energy and exergy efficiency in closed loop configuration at optimum M f R values were 26.41% and 3.09%, respectively. The overall CO 2 mitigation at optimum M f R was 182.6 tons for 20 years of considered systems life. The cost of freshwater of 0.018 $/kg (Rs. 1.5/kg) and the payback period of the SA-HDH system of 0.564 years were obtained at an M f R of 2.5 in closed-loop configurations, attributed to the higher freshwater yield.

Desalination has emerged as a vital solution to tackle global water scarcity, and among various desalination methods, the humidification–dehumidification cycle has garnered significant attention. This study provides a detailed review of performance enhancement techniques utilized in the humidification–dehumidification desalination systems. The review highlights previous studies conducted in this area. The humidification–dehumidification cycle, its working principles, and its advantages and drawbacks are then thoroughly discussed, establishing the groundwork for comprehending the significance of performance improvement strategies. The investigated techniques for multiple facets of the humidification–dehumidification cycle are multistage humidification–dehumidification, bubble columns, phase change materials, nanofluid application, variable pressure humidification–dehumidification, ultrasonic, and other techniques such as thermoelectric application, rotating belt, multiple insert, air saturator, fogging, and desiccant wheel. Through an extensive analysis of existing studies, the review summarizes the key findings of each technique, including improvements in system efficiency, freshwater production rates, heat and mass transfer rates, thermal energy storage, and reduced fouling. The findings provide valuable insights for researchers and practitioners, facilitating the selection and implementation of the most suitable techniques to achieve sustainable and efficient water desalination.

Regarding the increasing demand for freshwater supply worldwide in coming years, solar desalination systems have good potential for tackling this challenge. Solar humidification–dehumidification desalination system is a technology that can effectively supply the water demand for rural areas with brackish water resources. Parabolic dish collectors with cavity receivers are one of the heat source options for this desalination technique. The main challenge for a dish collector with a cavity receiver-based desalination system is the low freshwater production rate. The current research aims to utilize a heat pipe receiver in a dish collector to heat brackish water to the required temperature for the humidification–dehumidification desalination process. According to the results, the flow rate of the inlet brackish water varied between 0.3 and 0.4875 L min −1 , while the temperature of the outlet brackish water of the heat pipes ranged from 60.20 to 64.24 °C. Moreover, the results show that with the application of a heat pipe receiver, a maximum thermal efficiency of 35.79% was determined in the parabolic dish collector system for water sample with 10,600 μS cm −1 salinity. Moreover, 35.50, 35.30, and 35.08% were calculated for the average thermal efficiency values of the parabolic dish collector system for water samples with 3880, 10,600, and 21,500 μS cm −1 salinity, respectively. Also, the maximum outlet temperature for the brackish water samples with 3880, 10,600, and 21,500 μS cm −1 salinity were 63.98, 61.51, and 64.37 °C, respectively. According to the findings, heat pipe receivers lead to higher freshwater production rates than conventional cavity receivers.

Global warming has changed both the amount of global precipitation and the atmospheric capacity to retain water. In this paper, a novel definition of the long‐term Capturability of Atmospheric Water (CAW) based on horizontal atmospheric water transport is proposed, describing the ability of a certain area to intercept and convert the atmospheric water transported by horizontal moisture flux into local precipitation. The significant decrease of the CAW in Amazon and Congo rainforests and Inside Greenland indicates that these areas were having less precipitation with the same water vapor in the past 42 years, while in Asia (especially China), CAW is showing a large‐scale increasing trend, verifying the regional humidifying. Considering the change of both the CAW and the background atmospheric water simultaneously, their mismatch degree is also investigated. The positive mismatch in Qinghai Tibet Plateau, Greenland, and the Andes, suggests higher susceptibility to climate change, and in the areas of negative mismatch (Amazon, Maritime Continent, southeastern China, the Eastern United States, India, and Japan), a more stable precipitation response to climate change is expected. The proposed concept of CAW provides a novel perspective to analyze the precipitation response to climate change on a global scale. Key Points A novel definition of long‐term Capturability of Atmospheric Water (CAW) based on horizontal transport is proposed In the past 42 years, the CAW in the Amazon and Congo rainforests and the Greenland ice sheet has degraded significantly The findings provide a perspective to analyze the precipitation response to global climate change

The use of humidification-dehumidification water desalination technology has been shown to be a practical means of meeting the demand for freshwater. The aim of this review is to investigate the impact of salinity on HDH techniques that have various benefits in terms of both economics and the environment, including the capacity to operate at low temperatures, utilize sustainable energy sources, the need for low maintenance, and straightforward construction requirements. Also, in this review, it is observed that the HDH system’s components are strong and capable of treating severely salinized water. It can treat water in an appropriate way than other desalination technologies. This technology has recently been commercialized to treat highly salinized generated water. However, more research is needed to determine how salinity affects HDH productivity. According to several research investigations, while the specific thermal energy consumption increased considerably and the productivity of water per unit of time decreased significantly as the salt mass percentage grew, the purity of clean water did not suffer. The rejected brine must be reduced by increasing the total water recovery ratio in the HDH system. Through this review, it was found that brine control is becoming increasingly important in the water processing industry. ZLD systems, which aim to recover both freshwater and solid salts, can be a viable replacement for disposal methods. Finally, through this reviewer, it was concluded that HDH desalination systems may operate with extremely saline water while increasing salinity has a significant influence on system performance.

Water is essential for life on Earth. Desalination may reduce water shortages by turning salty water into drinkable water. We study a solar desalination process that combines a humidifier and a dehumidifier. The present work measures solar HDH desalination distinctively using an air-pressurized humidifier. This humidification technique employs an air-pressurized humidifier to increase water droplet dispersion and decrease droplet size. The experiment examines compressed air flow, air pressure, nozzle diameter, and humidification pattern breadth. Water output increases due to the broader spraying pattern and smaller air-pressurized nozzle. The suggested system produces 27.8 kg of distilled water every day for 0.0066 $ per liter.

Several concepts for platinum-based catalysts for the oxygen reduction reaction (ORR) are presented that exceed the US Department of Energy targets for Pt-related ORR mass activity. Most concepts achieve their high ORR activity by increasing the Pt specific activity at the expense of a lower electrochemically active surface area (ECSA). In the potential region controlled by kinetics, such a lower ECSA is counterbalanced by the high specific activity. At higher overpotentials, however, which are often applied in real systems, a low ECSA leads to limitations in the reaction rate not by kinetics, but by mass transport. Here we report on self-supported platinum–cobalt oxide networks that combine a high specific activity with a high ECSA. The high ECSA is achieved by a platinum–cobalt oxide bone nanostructure that exhibits unprecedentedly high mass activity for self-supported ORR catalysts. This concept promises a stable fuel-cell operation at high temperature, high current density and low humidification. A high oxygen reduction reaction activity can usually be realized by increasing platinum specific activity at the expense of active surface area. Self-supported platinum–cobalt-oxide networks combining high activity and surface area now promise a stable fuel-cell operation.

Many oxygen plants have been established specially during COVID-19 period and they are still serving for medical needs. The objective of the present work is to utilize solar and waste thermal energy of medical oxygen plants for water production. Humidification–dehumidification desalination (HDD) has been found suitable for this objective due to low temperature energy need during the process. The layout of an HDD unit has been presented to utilize waste heat, specially when solar energy is not much effective or absent. The system has been configured with a jet impingement solar air heater and a packed bed humidifier. A mathematical model has been developed and validated with the results of experiments. A comparative study of the proposed unit (HDD-O2) and a conventional unit has been performed in terms of yield and gained output ratio (GOR). The optimum flow rates of working fluids found in the range 0.03–0.04 kg/s and the temperature of air and water resulted in a continuous gain in yield. The average yield and GOR of the HDD-O2 unit were found to be 8.5 kg/d and 1.1 that could reach up to 11 kg/d and 1.4, respectively. The HDD-O2 unit provided yield at the cost of 0.04 $/kg with a payback period of 1.73 years. The findings of the present work indicated the suitability of the HDD-O2 plant for water production.