Humidity Research Articles

Molecular investigation of bamboo during stress relaxation using custom-built mechanical loading platform coupled with Raman spectroscopy

Bamboo holds significant potential as a substitute for plastics. Stress relaxation is a critical property during the fixation stage of plastic formation for bamboo products intended to replace plastic. However, research on this topic has been limited. In this study, a custom-built mechanical loading platform coupled with Raman spectroscopy was acquired during stress relaxation of bamboo under different humidity levels. Results reveal variations in stress relaxation patterns based on node position, radial location, and humidity, along with changes in cellulose molecules in response to these factors. Specifically, stress relaxation modulus in bamboo decreases from the outer to the inner part, increases in the presence of node structures, and decreases with increasing humidity. The shifts in Raman spectral bands exhibit significant changes in response to variations in stress and humidity. The elongation of cellulose chain bands at 1097 cm−1 in the Raman spectrum shows an increasing trend during stress relaxation, with larger band shifts observed at lower humidity. Simulations of cellulose molecular stretching show a stronger stress response at lower moisture content, with a maximum stress of 0.85 GPa for cellulose at 3.3 % moisture content, compared to 0.79 GPa at 7.8 % moisture content. These findings suggest a novel approach for the molecular investigation of materials during stress relaxation, which is crucial for the plasticity processing of bamboo.

Avaliação do conforto térmico em instalação de processamento de rapadura por meio do índice IBUTG

ABSTRACT The production process of non-centrifuged cane sugar (NCS) involves a significant release of steam and heat due to the evaporation of cane juices in saucepans over a solid fuel oven. This results in a warm and moisture-saturated environment, which can be suffocating for workers. This study aimed to evaluate the bioclimatic behavior of an NCS processing facility, based on the wet bulb globe temperature (WBGT) index. In addition, solutions are suggested to mitigate possible adverse effects of heat stress. This evaluation utilized computational simulations to determine the thermal comfort perceived by the workers. The accuracy of simulations was verified against temperature and relative air humidity data collected from the facility. Bioclimatic simulations encompassed twelve treatments, involving modifications to the enclosure on the walls and lantern window, incorporating three types of roof material. The WBGT index was determined by considering the effects of the radiant heat generated by the oven and the natural ventilation area on the facility’s temperature and relative air humidity. This helps to assess the comfort experienced by the workers. The thermal zone of the oven presented heat stress conditions; therefore, rest periods and mechanical ventilation were suggested when dissipating heat and steam through natural ventilation is not possible. For workers exposed to high temperatures and thermal radiation, the use of an aluminized apron and infrared goggles for eye protection was recommended.

Performance investigation of newly developed novel hemispherical solar dryer for sustainable food preservation: Comparative analysis with traditional methods

To preserve the world’s food resources, drying agricultural products is crucial for prolonging their shelf life. A novel concept of 1.5 m hemispherical solar dryer surmounts the limitations of conventional dryers like long drying time, solar tracking, large space requirement etc. Trials were performed on Thomson grapes to convert into raisins. For the purpose of fair accuracy in comparison, experiments were conducted on hemispherical solar dryer (active and passive mode), traditional cabinet solar dryer as well as open sun drying (OSD) by maintaining the uniform test conditions. An average moisture removal rate of 0.1935096 kg/h was obtained in hemispherical dryer. The hemispherical solar dryer significantly reduced drying time for converging grapes into raisins to 13 days, compared to 18 days in a cabinet solar dryer and 19 days with OSD. The hemispherical dryer, through a gap, creates a greenhouse effect, reaching a 70.1 °C maximum temperature and an average of 60.7 °C at 796 W/m2 average solar energy. The hemispherical dryer attained a drying efficiency of 5.67 %. Six mathematical models were employed for hemispherical and cabinet dryers. Amongst these Two term and Wang & Singh models were found suitable for the experimental data and provided precise prediction of moisture ratio.

Heat pump drying kinetics modeling and prediction for Lentinus edodes based on orthogonal experimental

To accurately understand the moisture variation and drying characteristics of Lentinus edodes (L. edodes) during the drying process, the kinetics model of L. edodes with a wider application range was investigated. First, the heat pump drying kinetics model for L. edodes was fitted, verified and extended based on the orthogonal experimental data. Then, the expression of moisture ratio of L. edodes with respect to drying time, air supply temperature (AST), loading density (LD) and circulating air volume (CAV) was proposed, and interaction effects of the three key parameters on the drying time were studied based on the prediction model. The findings indicated a substantial agreement between the predicted and experimental values. The drying time could be shortened by increasing the air supply temperature and the circulating air volume or decreasing the loading density. Among these three factors, the AST had the greatest impact on drying time, followed by CAV and LD. For every 48 g/m2 reduction in LD and 11.3 m3/h increase in CAV, the drying time could be reduced by 10.5 to 29.9 minutes. Similarly, increasing the AST by 1 °C and the CAV by 11.3 m3/h could decrease the drying time by 13.7 to 100.6 minutes. The research results are helpful to optimize the drying process, improve the drying efficiency, and provide guidance and references for practical production of L. edodes HPD.

Population dynamics of the main necrophagous Diptera in the sub-Sudanese zone of Côte d’Ivoire

The objective of this work was to identify the population variation of the main necrophagous Diptera in the sub-Sudanese zone of Côte d'Ivoire. Three traps, inspired by Upton's and using pig liver and viscera as bait were placed on the site of the Botanical Garden of Peleforo Gon Coulibaly University and Lataha located 10 km from the Botanical Garden. Weekly captures were taken from October 4, 2018 to October 3, 2019. In total, 194,853 individuals from the Calliphoridae, Sarcophagidae and Muscidae were collected. Calliphoridae represented 48%, Sarcophagidae 24% and Muscidae 28% in the Botanical Garden site and in Lataha, Calliphoridae presented 52%, Sarcophagidae 27% and Muscidae 21%. Chrysomya albiceps, Sarcophaga carnaria and Musca domestica were the majority species. The numbers of these three species were higher at relative humidity levels reaching 70 to 85%. A correlation between relative humidity and the numbers of these three species was observed. Apart from relative humidity, these results show that other climatic parameters have a weak influence on the activity of Chrysomya albiceps, Sarcophaga carnaria and Musca domestica. During this study, temperature and rainfall had little influence on the variation in the numbers of these three main species of necrophagous insects. However, the numbers of the three species were correlated with relative humidity levels.

Next-generation public health surveillance: extreme heat event prediction and monitoring system

Abstract Background Extreme Heat Events (EHEs) are a growing threat to public health. The increase in the frequency of occurrence of once rarer EHEs and the rise in their average temperatures are dangerously drastic for public health outcomes. Despite this, existing public health surveillance (PHS) systems fail to leverage IoT and AI technologies to facilitate real-time, continuous monitoring of EHE indicators and its associated health risks. This study closes this gap by proposing a comprehensive PHS system that can, in real-time monitor and predict EHE indicators to provide timely alerts to public health authorities. Methods The EHE PHS system collects EHE detection metrics, including indoor temperature and humidity levels, from IoT sensors and thermostats to map them across Canada, primarily focusing on low-income communities. The system also integrates historical climate data (surface temperature, humidity, wind speed and direction, and air quality indicators) from Environment Canada. The system uses the data to train initial prediction models including CNN, LSTM and GNN. The validated model will be integrated into the system, enabling real-time EHE prediction. The output will be displayed in user-friendly visualizations on the EHE PHS system’s dashboard capabilities. Results The system allows for the analysis of real-time data through dashboards and provides alerts when certain indicators (e.g. excessive or prolonged heat) detrimental to public health outcomes are detected. The alerts enable valuable lead time for public health authorities to implement proactive measures, such as issuing heat advisories and deploying resources to vulnerable areas. Conclusions The EHE PHS system will serve as a blueprint for global public health researchers, utilizing IoT and AI technologies for proactive crisis prevention. This knowledge will inform the development of heat-resilient policies and set a precedent for global public health crisis prevention. Key messages • The proposed EHE PHS system uses AI and IoT technologies, to enhance EHE prediction, risk identification, and real-time monitoring for effective public health interventions. • By integrating advanced predictive models and environmental data, the system facilitates early detection of EHE risk, which can significantly mitigate the health impact on vulnerable populations.

Leveraging digital platforms to improve Public Health in hospital smart buildings

Abstract The integration of digital platforms into hospital infrastructure represents a significant leap forward in public health management. This session explores how smart hospital buildings, equipped with advanced digital technologies, can enhance public health outcomes through more effective disease surveillance, improved environmental controls and enhanced patient care management. Smart hospital buildings utilize a range of new technologies such as IoT sensors, AI-driven analytics and big data solutions to monitor and optimize various aspects of hospital operations and care. These technologies enable real-time data collection on environmental conditions, patient health metrics and resource utilization, creating an ecosystem that not only supports the immediate health needs of patients but also contributes to broader public health goals. The session will address four key areas where digital platforms can make an impact: -Disease Surveillance and Management: Digital tools can track health data trends and patterns within hospital settings, enabling early detection of infectious outbreaks and more precise tracking of patient outcomes. -Environmental Monitoring: IoT sensors can continuously assess conditions such as air quality, temperature and humidity, which are critical for preventing hospital-acquired infections and ensuring a safe environment for patients and staff. -Resource Optimization: AI algorithms can analyse data to optimize resource allocation, ensuring that medical supplies and human resources are used efficiently, which is crucial in health emergencies. -Patient-Centred Care: Digital platforms can facilitate personalized patient care through real-time health monitoring and data analysis, ensuring timely medical interventions and better health management. This session will highlight case studies demonstrating successful implementation of digital technologies in smart hospital buildings and discuss the challenges and lessons learned from these initiatives.

Comparative Study of Raw and Water Rinsed Loa Janan’s Bituminous Coal Structure

East Kalimantan’s Coal has total humidity level at 18.21%, inherent humidity of 12.39%, fly ash content of 5.18%, volatile compounds of 38.22% and heat content of 6084 kcal/kg. However, chemical composition, functional group and crystallinity of raw and water rinsed Loa Janan bituminous coal have not been reported elsewhere. This research aims to investigate whether water rinsed treatment affects the structure of the coal or not. Coal size at 100 mesh-200 mesh is divided into 2, labeled as bituminous (a) stands for raw bituminous and bituminous (b) is for water rinsed-one. The bituminous (a) was analyzed using scanning electron miscroscopy (SEM)-energy dispersive xray (EDX), x-ray fluorescence (XRF), fourier transform infrared (FTIR) and powder x-ray diffraction (p-XRD) spectrophotometer. Meanwhile, bituminous (b) was heated at 40°C for 10 hours, cooled, rinsed using aquademin (1:5), stirred for 3 hours at 1500 rpm, and filtered. The bituminous (b) was heated at 40°C for another 10 hours and was characterized using the same technique as conducted to bituminous (a). Images revealed by SEM-EDX confirms the morphology ang topology of bituminous coal and the carbon content of them are 70.24% ± 0.87 (coal a) and 70.73% ± 0.08 (coal b). X-ray fluorescence analysis revealed that the bituminous (a) consisted of: Fe (46%), Si (21.5%), Al (5.4%) and bituminous (b): Fe (45%), Si (18.4%), Al (4.5%). There is a significant difference of their infrared spectra, both showed the peak at 1620 cm-1 (C=C) for carbon aromatic vibration. The wide area of peak at 3423 cm-1 is responsible for OH stretching vibration. Peaks intensity at 1620 cm-1 and 3420 cm-1 of bituminous (b) increased about 43.11% and 43.34%, respectively. The crystallinity degree of bituminous (b) (47.56%) is lower than that of bituminous (a) (69.72%). A sharp peak of XRD spectrum located at 2θ of 26.6o (hkl = 002) was responsible for both quartz and graphite.

Comparisons between the Direct and Indirect Effect of 1.5 keV X-rays and 0-30 eV Electrons on DNA: Base Lesions, Stand Breaks, Cross-Links, and Cluster Damages.

The interaction of low energy electrons (LEEs; 1-30 eV) with genomic material can induce multiple types of damage that may cause the loss of genetic information, mutations, genome instability, and cell death. For all damages measurable by electrophoresis, we provide the first complete set of G-values (yield of a specific product per energy deposited) induced in plasmid DNA by the direct and indirect effects of LEEs (GLEE) and 1.5 keV X-rays (GX) under identical conditions. Low energy photoelectrons are produced via X-rays incident on a tantalum (Ta) substrate covered with DNA and placed in a chamber filled with nitrogen at atmospheric pressure, under four different humidity levels, ranging from dry conditions to full hydration (Γ = 2.5 to Γ = 33, where Γ is the number of water molecules/nucleotide). Damage yields are measured as a function of X-ray fluence and humidity. GLEE values are between 2 and 27 times larger than those for X-rays. At Γ = 2.5 and 33, GLEE values for double strand breaks are 27 and 16 times larger than GX, respectively. The indirect effect contributes ∼50% to the total damage. These G-values allow quantification of potentially lethal lesions composed of strand breaks and/or base damages in the presence of varying amounts of water, i.e., closer to cellular conditions.

Detection of morphometric indicators of the soil surface of a grape plantation using spectral bands of satellite images

Introduction. Soils play an important role in the approximately 30-year period of operation of a grape planting, influencing plant growth, their yield and the quality of the grapes. In this study, the morphometric parameters of the surface soil layer of a grape plantation were studied using spectral channels of satellite images.Methodology. The methodology included the use of a “random forest” algorithm to classify soil cover using spectral channels and normalized satellite image indices and analyze the main physicochemical properties of soils. Accuracy was assessed using RMSD and confidence intervals calculated via bootstrapping.Results. The study revealed significant differences in the spectral reflectivity of different site options, which was due to carbonate content, humidity levels and the amount of humus. Areas with high carbonate and moisture content showed higher standard deviation values in the spectral channels. Studying the spectral characteristics of the soil surface makes it possible to effectively classify different areas based on remote sensing data. Analysis of combinations of spectral channels revealed an optimal set of three channels (B12, B11, B8A) with a minimum standard deviation when classifying an image into six soil variants of areas. For classification, a composition of five normalized indices can also be used, but in this case the calculation time increases significantly with a larger standard deviation and a larger confidence interval range. Using machine learning, six distinct soil surface types were segmented, demonstrating the complexity of the field›s soil mosaic. These results are critical for improving vineyard management and productivity

Experimental study and simulation of a solid desiccant cooling system installed in northern Algeria

An experimental investigation of a solid desiccant cooling system for a research laboratory on the Algerian coast has been carried out. The system utilized flat-plate solar collectors for regeneration and was evaluated through a combination of individual component characterization, system modeling (using TRNSYS), and experimental validation. The results obtained have been validated and show that the efficiency of the rotary heat exchanger reached 65 %, the evaporative humidifier efficiency reached 94 %, and the desiccant wheel achieved efficiencies of 73 % on the process side and 66 % on the regeneration side. This translates to a significant dehumidification effect, reducing absolute humidity in the treated air by 9 g/kg, for the supply air temperature effectively maintained at a comfortable 24 °C. The close agreement between the simulated and experimental COP values (1.13 and 1.08, respectively) validates the chosen approach and confirms the potential of this technology for energy-efficient building cooling in the hot and humid Mediterranean climate of northern Algeria.

Effect of heat stress, determination of temperature-humidity index

Relevance. Increased values of temperature and relative humidity of the external environment lead to negative consequences for the animal body, forcing the thermoregulation processes to be turned on. These mechanisms allow the animal organism to adapt to new environmental conditions at the expense of productivity. In these cases heat stress is observed. It is established that its manifestation is observed after 17 hours and there is a possible decrease in productivity by 35–40%. To identify the effect of heat stress, accurate determination of temperature-humidity index (THI) is necessary.Methods. The materials and methods contain the most common formulas for determining the temperature and humidity index. The equipment and software package used for the research are presented.Results. A graph of the results of South Korean studies is presented to compare the effects of heat stress on productivity. The results and discussions display a modernized formula for determining the heat stress index and figures showing the level of heat stress at different temperature and relative humidity levels.

Numerical Study on the Variable-Temperature Drying and Rehydration of Shiitake

Variable-temperature convective drying (VTCD) is a promising technology for obtaining high-quality dried mushrooms, particularly when considering rehydration capacity. However, accurate numerical models for variable-temperature convective drying and rehydration of shiitake mushrooms are lacking. This study addresses this gap by employing a model with thermo–hydro and mechanical bidirectional coupling to investigate five dehydration characteristics (moisture ratio, drying rate, temperature, evaporation rate, and volume shrinkage ratio) and a drying load characteristic (enthalpy difference) during VTCD. Additionally, a mathematical model combining drying and rehydration is proposed to analyze the effect of VTCD processes on the rehydration performance of shiitake mushrooms. The results demonstrate that, compared to constant-temperature drying, VTCD-dried mushrooms exhibit moderate shrinkage rates and drying time (16.89 h), along with reduced temperature variation and evaporation rate gradient (Max. 1.50 mol/(m3·s)). VTCD also improves enthalpy stability, reducing the maximum drying load by 58.84% compared to 338.15 K constant-temperature drying. Furthermore, drying time at medium temperatures (318.15–328.15 K) greatly influences rehydration performance. This study quantitatively highlights the superiority of variable-temperature convective drying, offering valuable insights for optimizing the shiitake mushroom drying processes.

The history of the breeding of Clematis (Clematis L.) in the M. M. Gryshko National Botanical Garden, NAS of Ukraine

Purpose. Investigate the history of Clematis breeding in the M. M. Gryshko National Botanical Garden (NBG), NAS of Ukraine, determine the main directions of hybrid Clematis breeding work. Results. It was established that the result of more than 16 years of breeding Clematis in the NBG was the selection of the 61 perspective hybrid, 42 of which, the most perspective, were assigned names. Of these, large­flowered varieties are the most numerous according to the distribution of variety groups in the current Royal Horticultural Society of Great Britain classification. In particular, Late Large­flowered account for about 40% of the total and Early Large­flowered for about 29%. Small­flowered hybrids make up the smaller part, of which about 26% belong to the Viticella group and one hybrid (‘Sputnik’) to the Integrifolia. The known directions of distribution of hybrid Сlematis of the NBG breeding indicate the possibility of their successful cultivation both in continental and maritime areas with a high level of humidity in the temperate zone and in the dry Mediterranean climate of the subtropical climate zone, which reveals their significant adaptive potential. Conclusions. Obtaining varieties of hybrid Clematis of domestic breeding is important for the implementation of sustainable horticulture practices on the territory of Ukraine, since a significant part of the modern introduced assortment of Clematis raises doubts about their adaptability to the local climate, and requires additional research into their adaptive potential. A successful combination in vertical landscaping of NBG­bred Clematis belonging to different varietal groups can ensure continuous flowering from May to the end of the season. These unique characteristics of Clematis ensure the creation of not only environmentally sustainable, but also visually appealing spaces that will contribute to the overall health and beauty of the urban environment.

Emissions and Flame Stability Assessment of Hydrogen Addition and Air Dilution in a Micro Gas Turbine Combustor Using 0D/1D Modeling by Chemical Reactor Network

Abstract Hydrogen emerges as a promising fuel for clean and sustain- able electricity production when utilized in micro gas turbines (mGTs). However, some challenges linked to hydrogen usage must be overcome as its high reactivity can lead to increased NOx emissions and flame instabilities. Literature suggests that combustion air humidification and/or exhaust gas recirculation (EGR) may be methods to reduce this reactivity. However, these measures are limited due to the small operating range of the mGT combustor. In this context, a 20 kWth mGT combustor is investigated un- der various inlet conditions to assess the effect of EGR towards increased flame stability and emission control when operating under hydrogen-enriched methane firing, using a Chemical Re- action Network (CRN) model. The CRN modeling is a fast and low computational complexity tool to model combustion perfor- mance and emissions by representing complex reactive flow fields through idealized reactor models, leading to reduced computa- tional costs. This study examines partial load conditions, fuel compositions, and the effect of combustion air dilution through EGR. The CRN model of the combustion process is designed based on combustion zones extracted from the main flow fields with similar thermo-chemical states from CFD, while emission predictions are experimentally validated for different operating points. Predicted NOx and CO emissions by the proposed CRN model show an acceptable agreement with the experimental data at high power loads. However, its accuracy diminishes for loads below 70% due to the variability in model tuning parameters across different loads, whereas the

Evaluasi Fungsi Ekologis Taman Kota pada Lanskap Riparian Sungai Cimanuk, Indramayu

The riparian landscape of the Cimanuk River has been declared a local protected area. Cimanuk Park is located on the northern coast of Java Island, Indramayu Regency which is one of the tourist centers and icons of the city of Indramayu. City parks are closely related to ecological functions that affect user comfort. This study aims to identify the diversity of vegetation, evaluate ecological functions, determine the perception of the people of Indramayu towards Cimanuk Park which is used as an icon of the city of Indramayu and provide recommendations for improving the green system of Cimanuk Park. The method of this research uses the study of aspects of ecological functions including microclimate measurement, and noise level measurement, which consists of preparation, inventory, analysis, assessment and evaluation, and preparation of recommendations. It has 17 species with a total of 333 individuals. This study conducted an assessment of vegetation diversity using the KPI method. Most of Cimanuk Parks have good categories in modifying temperature and controlling air humidity and have moderate categories in resisting wind, and reducing noise. Meanwhile, from the results of the study, the THI value was in the uncomfortable category.

Numerical Analysis of Optimising Liquid Desiccant Dehumidification for Sustainable Building Cooling: A Data-Driven Method Using Response Surface Methodology

Leveraging data-driven methods such as Response Surface Methodology (RSM) has considerable potential for sustainable building cooling via mitigating energy consumption and environmental impacts. This research focuses on using the RSM to improve liquid desiccant dehumidification for sustainable building cooling performance using a D-optimal design. Specifically, the research intends to investigate the actual influence of the inlet air conditions and desiccant concentration on the performance of liquid desiccant dehumidification systems, i.e., the moisture removal rates and dehumidifier efficiency. To systematically conduct this research, a set of experimental data gathered from the open literature is utilised. This includes a specific set of inlet parameters of air temperature (27–34.5 °C), ratio of air humidity (20.5–25 g/kg), and solution temperature (27.5–38.5 °C) as the independent variables. Also, the feedback variables include the moisture removal rates (MRR) and efficacy (ϵ). The associated results of the analysis of variation indicate that the ratio of air humidity has the greatest influence on the moisture removal rate. However, the solution temperature and the ratio of air humidity have the most influence on efficacy. In the event of response optimisation, the result at MRR and (ϵ) are 0.54 g/s and 0.50, respectively, with a minimum desirability of 0.992 and 1.

James Hutton and the measurement of atmospheric moisture

Measuring the amount of water in the air has been one of the most challenging of routine tasks in meteorology. From the 1650s onwards the methods involved either the uptake of moisture by organic materials such as human hair and whalebone (hygrometry) or the measurement of cooling due to loss of latent heat during evaporation (psychrometry). In 1792 James Hutton reported that a thermometer previously moistened by water records a lower temperature when exposed to cooling in the wind. This led to the development of the first condensation hygrometer by John Leslie in 1801 based on wet- and dry-bulb thermometers, whose design was refined and improved throughout the nineteenth century. Determining relative and absolute humidity values from a hygrometer required the use of a psychrometric equation, first developed by James Ivory in 1822 and later refined by Ernst Ferdinand August, James Apjohn and many others. Modern-day determinations of humidity often involve an aspirated psychrometer located in a Stevenson screen, whose origin can be traced directly back to Hutton’s observation of cooling due to evaporation. An extensive review of the literature on psychrometry records only cursory and ill informed acknowledgement of Hutton’s contribution. This article reasserts Hutton’s seminal role in the history of psychrometry.

High Ion-Conductive Hydrogel: Soft, Elastic, with Wide Humidity Tolerance and Long-Term Stability.

Ion-conductive hydrogels have received great attention due to their significant potential in flexible electronics. However, achieving hydrogels that simultaneously possess high ionic conductivity and stability under varying humidity conditions remains a challenge, limiting their practical applications. Herein, we propose a thermally controlled chemical cross-linking strategy to prepare an elastic and conductive hydrogel (ECH) of poly(vinyl alcohol) (PVA) with high content of H2SO4. The covalent cross-links formed effectively tackle the instability issue in high humidity of physically cross-linked PVA/H2SO4 hydrogels with high ionic conductivity, which were previously developed via the polymer-in-salt strategy. We systematically investigated the reaction conditions and clarified the methods to optimize the hydroxyl dehydration of PVA, resulting in excellent mechanical properties and ion conductivity simultaneously. The ECH demonstrates impressive ionic conductivity (up to 392 ± 49 mS cm-1) and elasticity (over 80% resilience upon stretching and compression after being equilibrated at various humidity levels for 24 days). Thanks to the excellent water retention of the high H2SO4 content, the ECH maintains an ionic conductivity exceeding 210 mS cm-1 for over 420 days at 50% relative humidity (RH) and retains over 100 mS cm-1 even after 3 days under extremely dry conditions (7% RH). These remarkable properties make the ECH an ideal candidate for applications requiring reliable ionic conductivity in diverse environmental conditions. Additionally, we demonstrated that the ECH can function as a stretchable Joule heater with high conformability for heating up objects with curved surfaces. The heating rate could reach a fast rate of ∼12 °C s-1 even when a human-safe alternating current voltage is below 36 V, attributed to the high ionic conductivity. We believe that the high performance and ease of fabrication make our hydrogels a promising candidate for use as electrolytes in flexible energy storage devices, electrolyte gates in electrochemical transistors, and artificial skin, which often face long-term stability challenges under varying humidity conditions.

Experimental investigation on the application of cold-mist direct evaporative cooling in data centers

The rapid development of the internet era has driven the construction of numerous data centers worldwide. In hot climate, data centers consume significant energy for cooling. Cold-mist direct evaporative cooling offers a natural cooling solution that can help reduce this energy consumption. This study investigates the temperature and relative humidity changes of natural high-temperature air after being cooled using a cold-mist direct evaporative cooling test bench. The effects of several control factors such as spray angle, spray flow rate, and air speed on the cold-mist direct evaporative cooling performance was systematically examined. The findings revealed that: (1) the optimal spray angle for cold-mist direct evaporative cooling treatment air is 65°; (2) high-temperature air between 27 °C and 37 °C can be cooled to 23.57 °C – 25.58 °C after cold-mist direct evaporative cooling treatment, with relative humidity levels of 67.0 % – 78.8 %, meeting the air supply requirements for data centers; (3) the proposed approach could reduce the data center energy consumption by 14 % – 41 %, while extending the annual natural cooling period by 3.16 % – 20.45 %.