Air Humidity Conditions Research Articles

Sub-Ppb H2S Sensing with Screen-Printed Porous ZnO/SnO2 Nanocomposite.

Hydrogen sulfide (H2S) is a highly toxic and corrosive gas commonly found in industrial emissions and natural gas processing, posing serious risks to human health and environmental safety even at low concentrations. The early detection of H2S is therefore critical for preventing accidents and ensuring compliance with safety regulations. This study presents the development of porous ZnO/SnO2-nanocomposite gas sensors tailored for the ultrasensitive detection of H2S at sub-ppb levels. Utilizing a screen-printing method, we fabricated five different sensor compositions-ranging from pure SnO2 to pure ZnO-and characterized their structural and morphological properties through X-ray diffraction (XRD) and scanning electron microscopy (SEM). Among these, the SnO2/ZnO sensor with a composition-weight ratio of 3:4 demonstrated the highest response at 325 °C, achieving a low detection limit of 0.14 ppb. The sensor was evaluated for detecting H2S concentrations ranging from 5 ppb to 500 ppb under dry, humid air and N2 conditions. The relative concentration error was carefully calculated based on analytical sensitivity, confirming the sensor's precision in measuring gas concentrations. Our findings underscore the significant advantages of mixture nanocomposites in enhancing gas sensitivity, offering promising applications in environmental monitoring and industrial safety. This research paves the way for the advancement of highly effective gas sensors capable of operating under diverse conditions with high accuracy.

Enhancing indoor thermal comfort prediction in tropical regions: A transfer learning strategy in West Bengal

Ensuring energy-efficient building management and sustainability necessitates precise thermal comfort prediction, a task particularly critical in tropical regions with significant energy-saving potential. This study confronts the complexities introduced by humid air conditions and escalating internal and external heat levels. The objective is to devise a sophisticated strategy for predicting indoor personal thermal comfort that enhances prediction accuracy. The proposed method extends beyond previous techniques by incorporating a comprehensive array of thermal comfort factors and their potential interdependencies, while also leveraging a transductive transfer learning strategy to circumvent data sparsity in the target domain. The experimental results indicate the presence of localized feature coupling within thermal comfort datasets, which the proposed CNN-ConvTrans model effectively processes, thereby enhancing predictive efficacy. The primary innovation of this work lies in the development of a novel transfer learning strategy that considers localized feature coupling, integrated with a deep learning model, effectively addressing issues such as class imbalance and data scarcity. This study furnishes an innovative and valuable framework for thermal comfort prediction across diverse environmental settings.

Investigation on Thermal Performance in Japan’s Local Station and Shopping District during Cold Season: Study Case of Kurosaki Arcade

Abstract This research delves into the spatial and thermal comfort conditions within the Kurosaki Shopping District, a market with a century-long history in Kitakyushu, Fukuoka. Despite the existing uncomfortable thermal conditions during winter, users actively engage in outdoor activities such as selling and opening stores. This research aims to understand the condition that the local user had to frequently withstand in the semi outdoor and outdoor area of Kurosaki District station and market’s urban area. Identifying issues related to thermal comfort in the outdoor areas, the study focuses on measuring and analyzing crucial parameters including air velocity, humidity, temperature, and spatial conditions. The method of data gathering uses Anemometer, Thermal recorder, and Globe Thermometer are utilized in 5 selected public areas that is actively frequented by local users. The research employs a comparative analysis method, juxtaposing the collected data with findings from literature reviews on standards and general comfort temperatures. The analysis reveals that temperature fluctuations are influenced by geographical factors and activity levels. The lack of building density contributes significantly to deviations in temperature and humidity from established standards. The study highlights the importance of addressing climatic conditions to enhance comfort in open spaces, especially in historically significant markets with extended operational histories. This research is expected to help policy makers understand the conditions of the local users and gather data for further research in the future.

Investigating dehumidification and heating performance in a dual evaporator heat pump system for electric vehicles

In cold, moisture-rich winter environments, window fogging represents a substantial safety hazard for drivers. Electric vehicles often incorporate heat pump systems to address challenges such as dehumidification and heating specific to cold weather. Therefore, it is essential to evaluate the dehumidification and heating efficiency of these systems through focused research. This study presents a dual-evaporator heat pump system designed specifically for electric vehicles, equipped with two distinct modes for dehumidification and heating. The research examines how factors such as inlet air volume and the degree of opening of the electronic expansion valve affect the system's dehumidification and heating performance. Experimental analyses were conducted to explore the system's response under various conditions of inlet air humidity and compressor speed in both modes. Results suggest that increasing inlet air volume improves dehumidification effectiveness but may reduce heating performance. Likewise, a wider opening of the electronic expansion valve enhances heating but could decrease dehumidification efficiency. Importantly, the study indicates that when the relative humidity of the inlet air exceeds 70 %, a single evaporator mode is more effective for dehumidification. However, when the relative humidity is below 70 %, the dual evaporator mode is more advantageous, showing better heating performance.

Performance analysis of ground source heat pump systems for constant temperature and humidity air conditioning in industrial buildings: a case study

Abstract The ground source heat pump (GSHP) system has gained widespread popularity for its provision of efficient and environmentally sustainable cooling and heating solutions for buildings. While the performance of GSHP systems has raised significant concerns, research predominantly focuses on residential and office buildings, leaving a gap in understanding their applicability in industrial settings with constant temperature and humidity air conditioning needs. This study aims to address this gap by evaluating the performance of a hybrid ground source heat pump (HGSHP) system implemented within a cigarette factory located in the hot summer and cold winter (HSCW) of China. Through a comprehensive analysis of operational data and long-term monitoring under three cooling conditions, essential parameters including water temperature characteristics, indoor temperature and humidity, system efficiency, power consumption, and soil temperature distribution were examined. The findings revealed that the weighted average coefficient of performance (COP) of the heat pumps (COPhp) and the whole system (COPsys) was decreased from 5.05 to 4.32 and 3.32 to 2.89, respectively. A positive correlation was observed between low cooling load high energy consumption, and low COP. The inlet temperature of the condenser exhibited a declining trend, which was attributed to the intermittent operation of condensation heat recovery. Furthermore, a comprehensive analysis of indoor temperature and humidity distribution within the controlled room was presented and found that almost all the rooms serviced by this system meet the specified design requirements. This research contributes to an enhanced understanding of the viability of HGSHP systems in industrial settings and provides valuable references for improving their energy efficiency and overall performance.

Sub-ppm short-chain fatty acids detection with La(III) modified SnO2 gas sensors

La(III) modified nanocrystalline SnO2 with lanthanum content [La]/([Sn] +[La]) = 0; 0.5; 1 and 2 mol. % were prepared by flame spray pyrolysis and characterized by X-ray diffraction, transmission electron microscopy (TEM), scanning electron microscopy (SEM) with energy dispersive X-ray (EDX) analysis, Inductively Coupled Plasma Mass Spectrometry (ICP-MS). Identification of surface segregation of La(III) containing phases was performed via Raman spectroscopy. Acidic properties of pure and La(III) modified SnO2 were characterized by temperature-programmed desorption of ammonia (TPD-NH3) with mass spectral determination of desorption products. It was demonstrated that decrease in the Lewis acidity of the SnO2 surface leads to the specific increase in sensor response when detecting gases with acidic properties like short-chain fatty acids (SCFAs) and H2S. The obtained materials are capable to detect SCFAs at ppb concentration level, including high air humidity conditions (RH = 80 %).

A Surrogate Model for the Rapid Evaluation of Electromagnetic-Thermal Effects under Humid Air Conditions

A Surrogate Model for the Rapid Evaluation of Electromagnetic-Thermal Effects under Humid Air Conditions

Investigation on sacrificial hydrolysis reaction of octadecyltrimethoxysilane for moisture resistance enhancement of metal–organic framework

Imparting water resistance is important for structures which is vulnerable to moisture to maintain the performance. In this study, octadecyltrimethoxysilane (ODTMS), which forms a hydrophobic surface through polymerization on the surface of the material, was used to enhance the hydrophobicity of HKUST-1 (HHK-x). This self-assembled structure reacts as sacrificial barrier to continuously penetrating H2O molecules and this effect is evaluated with detection of O–H peak (3323 cm−1) in FT-IR spectra. The gas adsorption performance is conducted with CO2 gas and the adsorption amount was reduced by 20 % (from 5.77 to 4.62 mmol/g at 25 °C, 1 bar) compared with the pristine HKUST-1 following the trend of specific surface area. However, water adsorption amount was reduced by 50.2 %, which is 2.5 times higher than the decrease in CO2 adsorption capacity. In addition, when the N2 adsorption and cycle adsorption performances were compared after exposing the sample to air for five days, it was confirmed that HHK-40 maintained its microporous structure and stable performance. The manufactured materials exhibited higher durability in a cyclic vapor sorption test depending on the loading amount of ODTMS and exhibits different tendency depending on the rate of humidity. These results experimentally indicate that accessible self-assembly process of ODTMS on water-vulnerable materials to be sustainable and stable in humid air conditions.

Environmental Exposome and Atrial Fibrillation: Emerging Evidence and Future Directions.

There has been increased awareness of the linkage between environmental exposures and cardiovascular health and disease. Atrial fibrillation is the most common sustained cardiac arrhythmia, affecting millions of people worldwide and contributing to substantial morbidity and mortality. Although numerous studies have explored the role of genetic and lifestyle factors in the development and progression of atrial fibrillation, the potential impact of environmental determinants on this prevalent condition has received comparatively less attention. This review aims to provide a comprehensive overview of the current evidence on environmental determinants of atrial fibrillation, encompassing factors such as air pollution, temperature, humidity, and other meteorologic conditions, noise pollution, greenspace, and the social environment. We discuss the existing evidence from epidemiological and mechanistic studies, critically evaluating the strengths and limitations of these investigations and the potential underlying biological mechanisms through which environmental exposures may affect atrial fibrillation risk. Furthermore, we address the potential implications of these findings for public health and clinical practice and identify knowledge gaps and future research directions in this emerging field.

Enhanced anchoring enables highly efficient and stable inverted perovskite solar cells

The immobilization of all-type ions is critical for further enhancing the efficiency and stability of inverted perovskite solar cells as the volatilization of organic cations and migration of halides could cause device degradation and non-radiative recombination. This work reports a novel and effective multidentate molecular “lock”, 2,3,4,5,6-Pentafluorophenylammonium Iodide (F5PhAI), to simultaneously immobilize all types of ions in perovskite with multiple chemical anchoring sites, leading to enhanced stability of perovskite under thermal and ambient conditions, as well as reduced defect density and energy disorder of perovskite films to significantly inhibit the non-radiative recombination. As a result, F5PhAI-modified device achieves an improved PCE of 24.03%, with a VOC of 1.124 V, a JSC of 25.14 mA cm−2, and an FF of 85.03%. Furthermore, the unencapsulated devices exhibit enhanced long-term stability, maintaining 85% and 90% of the initial efficiencies under 85°C thermal annealing in nitrogen for 500 hours and in humid air condition (RH: 60±10%) for 1000 hours, respectively. This work provides a novel and effective multidentate molecular “lock” strategy to achieve high-efficiency and stable inverted perovskite solar cells.

Direct CO2 capture from simulated and Ambient Air over aminosilane-modified hierarchical silica

Aminosilane-modified Hierarchical silica, HSA and HST-based adsorbents were synthesized by aminosilanization using Hierarchical silica (HS) with 3-aminopropyltriethoxysilane (APS) and N1-(3-trimethoxysilylpropyl)diethylenetriamine (TMPTA), respectively, and characterized to establish their physicochemical, structural, morphological, and porosity properties. Their CO2 adsorption performance was evaluated under direct air capture (DAC) conditions: 1) simulated air with CO2 concentration of 400 ppm in helium (He) at 30 °C and 2) indoor air with CO2 concentration ≥400 ppm at 30 °C, where HSA and HST modified with 70 wt% of respective aminosilanes outperformed others. The modified HS adsorbents showed an increase in kinetics, CO2 uptake under dry and humid conditions, stable cyclic adsorption-desorption performance, moderate enthalpy of desorption indicating a dominant chemisorption mechanism. Under dry and humid simulated air conditions (400 ppm CO2 in He), HSA-70 displayed a CO2 uptake of 0.82 mmol/g and 1.70 mmol/g, respectively, while HST-70 exhibited enhanced CO2 uptake of 1.54 mmol/g and 2.08 mmol/g, respectively. Cyclic stability of HSA-70 and HST-70 was confirmed through five thermal swing adsorption (TSA) cycles. In addition to this, their use for indoor air CO2 capture was also explored through ten short TSA cycles. Developed HSA-70 and HST-70 adsorbents exhibited more selectivity for CO2 over water, demonstrating their usage in practical direct air CO2 capture application.

Strong differences in microclimate among the habitats of a forest-steppe ecosystem

Microclimate has a substantial impact on plant composition, survival, and growth, as well as ecosystem processes. Although microclimatic conditions in anthropogenically fragmented ecosystems have received considerable scientific attention, they are understudied in naturally fragmented ecosystems, including forest-steppes. In addition, earlier investigations in these mosaics only measured microclimate parameters for a very short period (i.e., 24 hours on a single summer day). In the present study, the long-term microclimatic conditions were described in multiple habitat types, both woody and non-woody, in a sandy forest-steppe ecosystem in the Kiskunság, central Hungary. The aim of this study was to answer (1) how air humidity and temperature conditions differ among the studied habitats during the growing season and (2) which habitats are more stressed to vegetation growth regarding vapor pressure deficit (VPD). Wireless sensors recording air temperature and humidity values were used to monitor microclimatic parameters. VPD values were calculated based on the obtained air temperature and humidity, and two thresholds at 1.2 and 3.0 kPa were defined. To compare mean air temperature and humidity variables, as well as above-threshold VPD rate among habitat types, general linear models were used. Our results indicated that open grasslands were the warmest and driest habitats. Among woody habitats, south-facing edges had the harshest microclimatic conditions. The current work also found that small forest patches and larger forest patches had similar air temperature and humidity variables. Regarding VPD, open grasslands were the most stressed for vegetation growth from May to October. During the summer season, forest patches had a small moderating effect at the limiting threshold of 1.2 kPa VPD, but a stronger moderating effect at the 3.0 kPa threshold. With ongoing climate change, this role of forest patches is expected to become increasingly important in forest-steppes. Therefore, it is suggested that the remaining near-natural forest stands in sandy forest-grassland ecosystems should be prioritized for protection, and that scattered trees or groups of trees of native species should be established in extensive treeless grasslands.

Direct solar regenerated desiccant dehumidification system for sustainable ventilation in hot and humid climate

Conventional vapor-compression cooling for outdoor air dehumidification is energy intensive, especially in hot and humid regions. To reduce energy consumption, desiccant dehumidification wheels and packed beds are integrated with the air conditioning systems. However, these systems have large pressure drops and require external heating sources for regeneration. In this study, a two-stage direct solar-regenerated desiccant dehumidification rotating belt (SR-DDRB) system is proposed. The aim is to sustainably dehumidify the outdoor air while meeting the indoor humidity levels at enhanced indoor air quality and minimal energy. The system was sized, and its operation was optimized using artificial neural network for a case study of a typical office space located in hot and humid climate. The supplied outdoor air flowrate varied between 0.055 kg/s and 0.085 kg/s, which is much higher than the minimum required of 0.0392 kg/s. During months of high humidity, the operating conditions were affected by outdoor air humidity conditions such that higher outdoor air flowrate and bypass factor were achieved at low outdoor humidity, and vice versa. During months of low humidity, the operating conditions were primarily influenced by the outdoor air temperature rather than outdoor air humidity to minimize energy consumption. Over the cooling season and while operating at optimal conditions, the SR-DDRB system was able to meet an indoor relative humidity (RH) of 58 ± 1.5 %. Additionally, it maintained the CO2 concentration of 780 ± 41 ppm, well below the allowable 1,000 ppm, whereas electrical energy consumption was 78.8 kWh over the entire cooling season.

Assessment on liquid Li fire risk under humid air condition and with heat insulators

The IFMIF-like fusion neutron sources (FNSs) such as A-FNS and IFMIF-DONES have Li fire risks and the R&D activity for the Li fire risk reduction has been conducted under the IFMIF/EVEDA project. The objectives of this study are to experimentally elucidate humidity condition in airat which no Li fire ignites and the effect of the heat insulator on the Li fire ignition. The experimental set-up was designed and fabricated in order to perform Li fire experiments safely and systematically. Around 1 g of metallic Li samples were heated with and without the heat insulators as an experimental parameter of humidity in air. In this work, no ignition was observed under the less than 0.15 vol% humidity air. The heating experiments with the heat insulators clarified that the reaction between Li and the heat insulators causing Li fire ignition didn’t occur. In conclusion, the results of the present study suggest the conditions of less than 0.15 vol% humidity air and employing the heat insulator of alkaline earth silicate wool are useful for the Li target system of FNSs.

Yarn-Level Simulation of Hygroscopicity of Woven Textiles

Simulating liquid-textile interaction has received great attention in computer graphics recently. Most existing methods take textiles as particles or parameterized meshes. Although these methods can generate visually pleasing results, they cannot simulate water content at a microscopic level due to the lack of geometrically modeling of textile's anisotropic structure. In this paper, we develop a method for yarn-level simulation of hygroscopicity of textiles and evaluate it using various quantitative metrics. We model textiles in a fiber-yarn-fabric multi-scale manner and consider the dynamic coupled physical mechanisms of liquid spreading, including wetting, wicking, moisture sorption/desorption, and transient moisture-heat transfer in textiles. Our method can accurately simulate liquid spreading on textiles with different fiber materials and geometrical structures with consideration of air temperatures and humidity conditions. It visualizes the hygroscopicity of textiles to demonstrate their moisture management ability. We conduct qualitative and quantitative experiments to validate our method and explore various factors to analyze their influence on liquid spreading and hygroscopicity of textiles.

La4NiLiO8-assistant surface reconstruction to realize in-situ regeneration of the degraded nickel-rich cathodes

The cost-effectiveness and higher energy density of nickel-rich cathodes have made them appealing for electric vehicles, generating significant interest in their advancement. Unfortunately, the cathodes' high surface activity presents a challenge in humid air conditions, leading to structural degradation. The deterioration leads to the creation of the NiO rock-salt structure and residual lithium, impeding the pathways for Li+ movement throughout the entire system. Concurrently, the reduction of unstable Ni3+ triggers the generation of reactive oxygen species, causing the emergence of oxygen vacancies. These vacancies, in turn, diminish the cathode's structural stability. Herein, to mitigate the degradation of nickel-rich cathodes following storage, a surface reconstruction technique was employed to convert residual lithium and NiO phase into a conductive La4NiLiO8 repair layer. This in-situ regeneration resulted in an impressive regenerative electrochemical capacity of 56.2 mAh/g at 1C for the 28d-1La sample. Additionally, the surface reconstruction technique effectively decreased the concentration of oxygen vacancies, resulting in improved durability of the cathode structure. Furthermore, the La4NiLiO8 repair layer effectively suppressed detrimental phase transitions and mitigated electrolyte corrosion. This study presents a straightforward and efficient regeneration strategy for degraded nickel-rich cathodes resulting from storage.

Physiological processes in Phalaenopsis pulcherrima cultivated in hermetically sealed vessels

The hermetic condition is the least studied factor associated with the spaceflights. Phalaenopsis pulcherrima is promising for space farming as it can be cultivated in small substrate blocks, and its photosynthetic apparatus is well adapted to elevated CO2 concentrations and temperatures.Three-year-old meristematic P. pulcherrima plants were planted into plastic (acrylic) vessels filled with fibrous substrate. In control, vessels had an open top. The hermetic conditions were reached by sealing the vessels’ covers with a parafilm. Both control and hermetic vessels were placed in a plant growth chamber where test plants were cultivated under controlled conditions of air temperature, illumination, air humidity, and soil moisture. After 6 and 24 months of cultivation, the CO2 concentration in the hermetic and control vessels was measured, and the physiological characteristics of each test plant, such as the content of macro- and micronutrients, photosynthetic pigments, free amino acids, and content of labile carbohydrates (%) in the leaves of the test-plants were determined.It was revealed that cultivation of P. pulcherrima in hermetic conditions affected its basic physiological processes such as photosynthesis, mineral nutrition, carbohydrates, and amino acid metabolisms. The effect size of this stress factor depended on the duration of exposition period. Long-term cultivation of P. pulcherrima under hermetic conditions promoted the accumulation of nonenzymatic antioxidants (viz. chlorophyll b, carotenoids, and amino acids), which contributed to the adaptation of this orchid species to oxidative stress caused by hermetic environment.

Transmission of COVID-19 in Cities with Weather Conditions of High Air Humidity: Lessons Learned from Turkish Black Sea Region to Face Next Pandemic Crisis

The goal of this study is to analyze associations between COVID-19 transmission and meteorological indicators in cities of the Black Sea region of Turkey, located specifically in the dampest area, with excess rainfall and recurring fog. In particular, the working hypothesis is that the widespread transmission of new coronavirus SARS-CoV-2 (leading to the airborne disease COVID-19) in cities can be explained by specific weather conditions, namely high levels of air humidity. Statistical evidence here does not seem, in general, to support the hypothesis that the accelerated transmission of COVID-19 in the studied cities can be explained by high levels of humidity because different meteorological, environmental, demographic, and socioeconomic factors also plays a critical role in the disease transmission dynamics of the investigated region. The main implications of our findings here are that the demographic structure of the population, climate indicators, organization of the health system, and environmental factors (e.g., air pollution, etc.) should be considered through a systemic approach when designing effective national and regional pandemic plans directed to implement health policies for facing new variants of COVID-19 and/or new airborne diseases, in order to reduce their negative effects on health, social and economic systems.

Spatial, Temporal, and Vertical Variability of Ambient Environmental Conditions in Chinese Solar Greenhouses during Winter

The monitoring and control of environmental conditions are crucial as they influence crop quality and yield in Chinese solar greenhouses (CSGs). The objectives of this study were to assess the spatial, temporal, and vertical variability of major environmental parameters in CSGs during winter and to provide greenhouse climate/microclimate characteristics in order to facilitate the monitoring and control of greenhouse environmental conditions. A wireless sensor network (WSN) was deployed in two CSGs: one with crops and one without. Sensors were placed at different locations inside and outside the greenhouses, and the air temperature, humidity, CO2 concentration, light intensity, solar radiation, and wind conditions were measured and analyzed. Significant variability in the spatial, temporal, and vertical distribution of environmental factors was observed in both greenhouses. The average minimum and maximum temperatures and humidity inside the CSG with crops were 9.96 °C (4:00 h) and 24.5 °C (12:00 h), and 32.6% (12:00 h) and 92.1% (5:00 h), respectively. The temperature difference was 2.2 °C between layers in the CSG without crops and 1.4 °C between layers in the CSG with crops. The CO2 concentration in the different layers inside the CSG with crops was highest at night. The average maximum light intensity inside the CSG with crops was 32,660.19 lx, 36,618.12 lx, and 40,660.48 lx (12:00 h to 13:00 h) in the bottom, middle, and top layers, respectively. Sensor positioning in the greenhouse was evaluated by considering the sensors’ data variability. The findings of this study could aid in the development of a better monitoring and control system for CSG’s microclimate during winter. More research is needed on greenhouse microclimate control systems based on this variability analysis, which could improve crop quality and yield in greenhouses.

Quantifying the influence of transmission path characteristics on urban railway noise.

Every ambient noise study employs the source-path-receiver structure to explore the overall behaviour of sound. Noise levels are affected by changes in distance, intervening barriers, and atmospheric conditions along the transmission path between the source and the receiver. The objective of this study is to quantify the influence of transmission path characteristics for a realistic time-varying moving line source. In this context, railway noise was considered to explore the variance of noise in an urban setting over a variety of measuring distances, including 25, 50, 100, and 200 m, with variables such as air temperature, humidity, and wind condition. The data corresponding to 106 trains was collected for analysis, and it was observed that the effect of the wind was more significant for larger distances between the source and the receiver. When the sound levels were measured in two opposite wind directions, a considerable noise level difference was observed. For every 1 m/s increase in wind speed, within a distance of 50 m, the average sound attenuation induced by the upwind phenomena was 0.2 dBA. The impact of air temperature changes on received sound level from a moving source was insignificant within the range of temperatures considered in the study. The effect of humidity is less at shorter distances but at larger distances, increasingly attenuates noise levels. Analysis of variance was performed on the selected variables to determine whether the means of each group were significantly different from each other and found that train speed had a more significant impact on railway noise compared to other parameters.