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In order to solve the problem that the current fan coil units control method only takes indoor temperature as a single control object and ignores humidity, an office building in Beijing with fan coil units and fresh air system was studied. To obtain a better joint control satisfaction rate of indoor temperature and relative humidity, a reinforcement learning control method based on action intervention was proposed for regulating the air supply volume of fan coil units. A reinforcement learning algorithm was deployed using TensorFlow, a building energy system simulation model was built in TRNSYS, and the proposed algorithm was trained, tested and evaluated by using a self-developed TRNSYS-Python co-simulation platform. The results show that the proposed control method can improve the joint control satisfaction rate of indoor temperature and relative humidity by at least 9. 5% compared with the traditional onoff control and rule-based control. It is concluded that the proposed method is valuable in engineering application and provides a new research idea for improving indoor thermal comfort in buildings [ABSTRACT FROM AUTHOR]

Objectives: Exposure to aerosol particles generated from tooth grinding has a negative impact on the health of dental personnel. The aim of this study was to quantitatively analyze the impact of indoor relative humidity (IRH) on the deposition of these suspended particles in a well-controlled dental environment. Materials and methods: In this study, a humidity control system was employed to effectively regulate and maintain indoor relative humidity (IRH). A novel computer-assisted numerical control system was developed to pre-treat the molar specimens, and accurately simulate clinical tooth grinding procedures. Each procedure was performed in triplicate, with an online real-time particle counter (ORPC; TR-8301, TongrenCo.) measuring aerosol production. All testing devices were controlled remotely. The data obtained were statistically analyzed using descriptive statistics and non-parametric tests (Kruskal–Wallis/ Dunn’s post hoc test with Bonferroni correction, p < 0.05). Results: The findings showed that with increasing IRH, the maximum peak concentration of aerosol particles decreased by 397% from 6.51 × 107 particles/m3 at 30% to 1.64 × 107 particles/m3 at 80%. The Kruskal–Wallis test results indicated a statistically significant effect of IRH on the aerosol increment (p < 0.05). Conclusions: Increasing the IRH level can effectively promote the deposition of aerosol particles, with a return to baseline within 15 min after reaching 60% or above. Clinical Relevance: Our study suggested that maintaining IRH above 70% during the cleaning process, allowing natural recovery to ambient humidity levels within 15 min after cleaning, and taking basic precautions, may lead to an adequate reduction in the possible health risks of aerosol contamination. [ABSTRACT FROM AUTHOR]

To investigate the effect of inlet gas relative humidity on the performance of proton exchange membrane fuel cell stack under variable load conditions, the dynamic cycling condition was designed with two step conditions of current densities ranging from 0. 10 to 0.35 A/cm² and from 0. 10 to 1.00 A/cm², and steady state condition of current densities of 0. 10, 0.35 and 1.00 A/cm². Five sets of tests with humidity levels of 20%, 30%, 50%, 70% and 80% were performed. The results show that the sensitivity of the stack to humidity is different at different current densities under the constant current condition, and humidity has great impact on the stack performance at high current density. The stack voltage appears to be downstroke and upstroke in the variable load process, and the amount of voltage downstroke in the loading process is related to the variable load amplitude and humidity, while the voltage consistency of single cell of the stack is deteriorated and related to the inlet gas relative humidity.` [ABSTRACT FROM AUTHOR]

Long-lasting drought records can provide valuable insights into the history of hydroclimate change in central China, but meteorological records are too short to capture long-term variability of the humidity. In this study, we established a tree-ring width chronology of Pinus armandii Franch in the Funiu Mountains region of central China. Correlation analyses showed that tree radial growths were mainly limited by hydrothermal combination in May–June. The results of the moving correlation analysis further showed that the response relationship between tree growth and relative humidity in May–June (RH MJ) was the most stable. This relationship has been reconstructed since 1863. The variance of the reconstructed RH MJ was explained by 41.7% (40.6% after adjusting for degrees of freedom). Over the past 158 years, there were 3 wet periods and 4 dry periods. The spectral analysis revealed that the reconstructed RH MJ exhibited quasi-periods of 2-4a and 31.6a, and cross-spectrum analysis showed that the reconstructed RH MJ may be related to ENSO, PDO, solar activity and the East Asian summer monsoon. The spatial correlation analysis revealed that the reconstructed RH MJ accurately depicted the fluctuations in humidity within the Huanghe-Huaihe Plain. Furthermore, the reconstructed RH MJ exhibited a strong negative correlation with the sea surface temperature (SST) of the subtropical North Pacific, while it displayed a highly significant positive correlation with the SST of the eastern equatorial Pacific from the previous May to the current April. This also indicated a possible link between humidity fluctuations in the Huanghe-Huaihe Plain and the Pacific internal variability in climate system. Therefore, this research aims to expand and complement the existing meteorological records, providing important reference significance for forest management, agriculture, and animal husbandry. [ABSTRACT FROM AUTHOR]

Observations and models show that near‐surface relative humidity is nearly constant at ∼80% over the ocean in the current climate, and almost invariant in the global mean in projected future climates. Here, this behavior is investigated through the development of a simple theoretical model for near‐surface relative humidity by considering the moisture balance above a uniform ocean surface. The relative humidity is predicted to depend on only the near‐surface wind speed, air‐surface temperature difference, surface wetness and large‐scale moisture convergence. Although developed in the context of moist over‐ocean convection, the theory is able to determine the relative humidity in a suite of idealized simulations over both wet and dry surfaces with a root‐mean‐square error of less than 3%. The theory also predicts the climatology of relative humidity over the ocean with a root‐mean‐square error of less than 3%. The theory thus provides a theoretical basis for investigating changes in relative humidity over the ocean, water vapor feedbacks and the water cycle in current and future climates. Plain Language Summary: Relative humidity is the water content of air relative to its saturation value. Observations and climate models show that global mean near‐surface relative humidity is almost invariant in a changing climate, an observation which underpins the enhancement of the water cycle with increasing global mean temperatures and surface radiative feedbacks. Furthermore, relative humidity over the ocean, whether in the tropics or polar regions, takes a near uniform value of ∼80%. However, a theoretical basis for this remarkable invariance of relative humidity has not been previously established. Here we show that near‐surface relative humidity is controlled by the geometry of moist convection over the ocean surface. Its value is set by a non‐dimensional geometric constant and is independent of the absolute air temperature, with weak dependence on near‐surface wind speeds, air‐surface temperature difference and large‐scale moisture convergence. Hence, the over ocean relative humidity is largely climate and latitude invariant. Key Points: Convection above the ocean surface exhibits a characteristic geometry that controls the value of near‐surface relative humidityA quadratic equation is derived to predict near‐surface relative humidity in terms of known surface properties and a geometric constantThe equation predicts the relative humidity in idealized simulations and ocean observations with less than 3% error [ABSTRACT FROM AUTHOR]

Patulin is a mycotoxin produced by several species of Penicillium sp., Aspergillus sp., and Byssochlamys sp. on apples and pears. Most studies have been focused on Penicillium expansum , a common postharvest pathogen, but little is known about the characteristics of Penicillium paneum. In the present study, we evaluated the effects of temperature, pH, and relative humidity (RH) on the growth of P. paneum OM1, which was isolated from pears, and its patulin production. The fungal strain showed the highest growth rate at 25 °C and pH 4.5 on pear puree agar medium (PPAM) under 97 % RH, while it produced the highest amount of patulin at 20 °C and pH 4.5 on PPAM under 97 % RH. Moreover, RT-qPCR analysis of relative expression levels of 5 patulin biosynthetic genes (patA , patE , patK , patL, and patN) in P. paneum OM1 exhibited that the expression of the 4 patulin biosynthetic genes except patL was up-regulated in YES medium (patulin conducive), while it was not in PDB medium (patulin non-conducive). Our data demonstrated that the 3 major environmental parameters had significant impact on the growth of P. paneum OM1 and its patulin production. These results could be exploited to prevent patulin contamination by P. paneum OM1 during pear storage • The highest growth of P. paneum OM1 at 25 °C and pH 4.5 under 97 % relative humidity. • The highest patulin production by the fungus at 20 °C and pH 4.5 under 97 % relative humidity. • The expression of patA , patE , patK , and patN was up-regulated in YES medium. • The expression of patA , patE , patK , and patN was not up-regulated in PDB medium. • The expression of patL remained constantly in both YES and PDB media. [ABSTRACT FROM AUTHOR]

• The Quicklime digestion in SJM can transform all the CaO into Ca(OH) 2. • SJM digested desulfurizer has a wider desulfurization temperature. • SJM digested desulfurizer performance is better than TDD desulfurizer. • SJM digested desulfurizer has superior performance at low relative humidity. Low desulfurization efficiency impedes the wide application of dry desulfurization technology, which is a low-cost and simple process, and one significant solution is the development and manufacture of high-performance desulfurizers. In this study, firstly, a steam jet mill was used to digest quicklime; then, we utilized numerical simulation to study the flow field distribution and analyze the driving factors of quicklime digestion; and lastly, the desulfurization performance of the desulfurizer was evaluated under different relative humidities. The results show that the desulfurizer prepared via the steam jet mill had better apparent activity than traditional desulfurizers. Also, the entire jet flow field of the steam jet mill is in a supersonic and highly turbulent flow state, with high crushing intensity and good particle acceleration performance. Sufficient contact with the nascent surface maximizes the formation of slaked lime. The experiments demonstrated that the operating time with 100% desulfurization efficiency and the "break-through" time for the desulfurizer prepared via the steam jet mill is longer than that of traditional desulfurizers, and has significant advantages, especially at low flue gas relative humidity. Compared with traditional desulfurizers, the desulfurizer prepared via steam jet mill expands the range of acceptable flue gas temperature, and the failure temperature is 1.625 times that of traditional desulfurizers. This work breaks through the technical bottleneck of low dry desulfurization efficiency, which is an important step in pushing forward the application of dry desulfurization. [ABSTRACT FROM AUTHOR]

As a biodegradable and biocompatible polymer material, polyglycolic acid is attracting more and more attention in the field of polymeric and biomedical materials. Consequently, the study of the transformation between different crystal forms of glycolide, the monomer of polyglycolic acid, is of great importance, because crystal forms of glycolide determine the stabilities and properties of polyglycolic acid products polymerized under different conditions in industry. Herein, this article reports the synthesis and crystallization of α‐ and β‐glycolide controlled by the type of organic solvents and/or temperatures, during which an intermediate crystal form of β′‐glycolide is newly observed. The transformation between α‐, β‐, and β′‐glycolide is investigated in detail, and the stabilities of different crystal forms are illustrated via the controlled experiments under different relative humidity (RH) as well as the theoretical calculations, which should provide fundamental concepts and guidance for the industrial production of glycolide and optimization of polyglycolic acid products. [ABSTRACT FROM AUTHOR]

The PurpleAir PA-II sensor provides low-cost in situ measurements of meteorological variables including temperature and relative humidity (RH), as well as fine particulate matter (PM2.5) in real time. The sensors have been used in several studies investigating intracity differences in temperature and PM2.5. While the adoption and use of low-cost sensors has many benefits, care must be taken to ensure proper calibration and testing. This is true not only for PM2.5 measurements but also for temperature and RH given the synergistic health impacts from extreme heat and air pollution exposure. Here, we compare continuous temperature and RH measurements from a PA-II sensor to measurements from a Campbell Scientific 107 temperature probe and Vaisala HMP45C RH probe. All three instruments were co-located from December 2021 to June 2023 in Asheville, North Carolina. We found that the PA-II has an overall high temperature bias of 2.6 °C and root mean square error (RMSE) of 2.8 °C. Applying a linear regression correction reduces RMSE to 1.0 °C, while applying the constant 4.4 °C correction suggested by PurpleAir reduces RMSE to only 2.2 °C. Our PA-II RH measurements have a low bias of −17.4% and uncorrected RMSE of 18.5%. A linear regression correction improves the RH RMSE to 4.5%. Applying the constant 4% RH correction suggested by PurpleAir reduces RMSE to only 14.8%. We present new correction factors that differ from those suggested by PurpleAir, which overcorrect the high temperature bias and undercorrect the low RH bias. We also show that our correction factors improve estimates of dewpoint temperature (RMSE of 0.6 °C and 0.9 °C) compared to the corrections suggested by PurpleAir. [ABSTRACT FROM AUTHOR]

Buffer material (compacted bentonite), one of the engineered barrier elements in the geological disposal of a high-level radioactive waste, develops swelling stress due to groundwater penetration from the surrounding rock mass. Montmorillonite is the major clay mineral component of bentonite. Even previous studies provide few mechanical and thermodynamic data on Ca-montmorillonite. In this study, thermodynamic data on Ca-montmorillonite were obtained as a function of water content by measuring relative humidity (RH) and temperature. The activities of water and the relative partial molar Gibbs free energies of water were determined from the experimental results, and the swelling stress of Ca-bentonite was calculated using the thermodynamic model and compared with measured data. The activities of water and the relative partial molar Gibbs free energies obtained in the experiments decreased with decreasing water content in water contents lower than about 25%. This trend was similar to that of Na-montmorillonite. The swelling stress calculated based on the thermodynamic model was approximately 200 MPa at a montmorillonite partial density of 2.0 Mg/m3 and approximately 10 MPa at a montmorillonite partial density of 1.4 Mg/m3. The swelling stresses in the high-density region (around 2.0 Mg/m3) were higher than that of Na-montmorillonite and were similar levels in the low-density region (around 1.5 Mg/m3). Comparison with measured data showed the practicality of the thermodynamic model. [ABSTRACT FROM AUTHOR]

Emerging infestations of bed bugs are affecting normal human lifestyle globally. This study has been designed to optimize the rearing conditions for Cimex lectularius L. (Hemiptera), to support the scientific research on them. Bed bugs have been projected onto three different temperature (20 °C, 25 °C, and 30 °C) and relative humidity (50%, 70%, and 90%) conditions to check their overall growth and survival rate. Adult mortality, weight loss, egg laying, percentage hatching, hatching initiation and completion, nymph mortality, and molting have been evaluated to optimize the best conditions. The temperature at 25 °C with 90% RH showed minimum mortality for adults (female 13.33 ± 3.33% and male 6.67 ± 3.33%) and nymphs (13.33 ± 3.33%), while maximum egg laying (40.33 ± 1.86), with highest percentage hatching (98.23 ± 0.58%). At 30 °C with 90% RH, hatching initiation and completion (5.19 ± 0.12 days and 7.23 ± 0.16 days) as well as molting initiation and completion (3.73 ± 0.12 days and 7.00 ± 0.24 days) were found to be fastest. Thus, it can be concluded that 25 °C with 90% RH is ideal for rearing of adults and 30 °C with 90% RH is appropriate for rapid growth of nymphs. [ABSTRACT FROM AUTHOR]

In the light of sustainability, the nearly forgotten control of relative humidity (RH) in display cases with saturated salt solutions is re-evaluated. Spilling and creeping of salts can be avoided. By choosing magnesium nitrate or potassium carbonate, the temperature dependence of the RH and the emission of harmful gases are negligible. Measurements with metal oxide semiconductor (MOS) gas sensors showed such solutions to be excellent absorbers for corrosive pollutants such as acids and aldehydes, especially the alkaline potassium carbonate (hitherto not used in museums). The practical application of such solutions in display cases is currently being tested in a community science project in a number of museums. This will result in improved guidelines for conservators and it is hoped, in a revival of this passive, failsafe, low-carbon footprint technique. [ABSTRACT FROM AUTHOR]

Atmospheric new particle formation (NPF) is an important source of aerosol particles and cloud condensation nuclei, which affect both climate and human health. In pristine environments, oxidation of biogenic volatile organic compounds (VOCs) is a major contributor to NPF. However, the impact of relative humidity (RH) on NPF from these precursors remains poorly understood. Herein, we report on NPF, as inferred from measurements of total particle number density with a particle diameter (dp) > 7 nm, from three VOCs (sabinene, α-terpineol, and myrtenol) subjected to dark ozonolysis. From a series of comparative experiments under humid (60% RH) and dry (~0% RH) conditions and a variety of VOC mixing ratios (ξVOC, parts per billion by volume, ppbv), we show varied behavior in NPF at elevated RH depending on the VOC and ξVOC. In general, RH-dependent enhancement of NPF at an ξVOC between <1 ppbv and 20 ppbv was observed for select VOCs. Our results suggest that gaseous water at particle genesis enhances NPF by promoting the formation of low-volatility organic compound gas-phase products (LVOCs). This is supported by measurements of the rate of NPF for α-pinene-derived SOA, where RH had a greater influence on the initial rate of NPF than did ξVOC and ξO3. [ABSTRACT FROM AUTHOR]

Simple Summary: In the last decades, the number of available chemical pesticides for pest control has been dramatically reduced due to their possible negative effects on human health and the environment. Therefore, there is an immediate necessity to explore alternative products to chemical pesticides for pest control, with natural zeolites (zeolitic rocks) being among the potential options. The olive fruit fly, Bactrocera oleae Gmelin (Diptera: Tephritidae), is one of the most harmful pests of olives in Mediterranean countries and worldwide. In this study, we evaluated the oviposition-deterrent effect of a natural zeolite on the olive fruit fly under different temperatures and relative humidity conditions. The tested natural zeolite was highly effective in deterring egg laying in B. oleae females under all tested conditions. These findings are poised to advance our understanding of sustainable and eco-friendly strategies for pest control in olive orchards, presenting opportunities for the development of targeted interventions that align with both environmental conservation and effective agricultural practices. In recent years, the number of available chemical pesticides has been dramatically reduced, urging the need for the discovery of alternatives to chemical pesticide products such as, among others, natural zeolites (zeolitic rocks). We determined the mineralogical and chemical composition of a specific and continuous layer of zeolitic rock sample (ZeotP) from Petrota, Evros, Greece, and evaluated its oviposition-deterrent effect on the olive fruit fly Bactrocera oleae Gmelin (Diptera: Terphritidae). The tested natural zeolite contained 70 wt. % clinoptilolite, 18 wt. % amorphous material, 7 wt. % feldspars, 4 wt. % cristobalite, and 1 wt. % quartz. We tested the oviposition-deterrent effect of ZeotP mixed or not with an emulsifier adjuvant, NU-FILM-P®, in water and applied it to the surface of olive fruits. The ZeotP oviposition-deterrent effect on the olive fly was very high under a series of tested temperatures (17 °C, 20 °C, 25 °C, and 30 °C) and RHs (23%, 33%, 55%, 75%, and 94%). In addition, the ZeotP residual deterrent effect after equable water spraying was high, like the respective effect of the pyrethroid insecticide Decis® (deltamethrin). Our results may contribute to the effective control of the olive fruit fly using an alternative to chemical pesticides: natural zeolite (zeolitic rocks) products. [ABSTRACT FROM AUTHOR]

The moisture content within the concrete pore network significantly influences the mechanical, thermal, and durability characteristics of concrete structures. This paper introduces a novel fully embedded wireless temperature and relative humidity sensor connected to an automatic acquisition system designed for continuous concrete monitoring. Relative humidity measurements from this new sensor are compared with those obtained by a commercial system based on the borehole method at different depths (2.5 and 4.0 cm) and exposure conditions (oven drying and humid chamber). The results allow for proving that both systems provide consistent internal relative humidity measurements aligned with the exposure conditions and highlight the capability of fully embedded wireless sensors as a practical and reliable alternative to the conventional borehole method. Additionally, the continuous monitoring of the wireless cast-in sensor exhibits reliability during unintended temperature fluctuations, emphasizing the effectiveness of permanently installed sensors in promptly detecting unintended curing variations in real time. The continuous real-time information provided combined with the practicality of these sensors might assist construction managers to improve the quality control of the concrete curing process and shrinkage behavior, and ensure the integrity of concrete surface finishing. [ABSTRACT FROM AUTHOR]

The rapid industrialization of nations in Southeast Asia (SEA) has led to a decline in these countries' air quality, including high levels of particulate matter (PM). Monitoring these air pollutants is crucial to understanding the pollution status of the area and developing management plans for improvement. The metrological conditions in the region present challenges as high temperature and high humidity have been known to cause errors in the measurements. This study investigated the performance of five PM monitoring instruments with different working principles. The air temperature was mostly over 25 °C with relative humidity usually remaining above 80%, which is typical of SEA weather. Measurements from all instruments had good correlations with each other as their linear regressions yielded slopes of 1 ± 0.15 and R2 > 0.65. Moreover, this study found that depending on the chosen reference instrument, not all factors affect the devices equally. In particular, using Partisol as a reference, the PM2.5 concentration, air temperature, and relative humidity had less impact upon the relative bias level compared to using Leckel as a reference. In addition, the high cost of monitoring instruments also poses financial constraints on how many monitoring stations can be deployed. To tackle this issue, this study presents ManPMS whose design is based on that of the USEPA Title 40 Part 50 with slight modifications. The cost to manufacture and assemble the instrument was only 2/3 the price of a typical instrument with similar performance. [ABSTRACT FROM AUTHOR]

A spatiotemporal analysis is applied to examine the decadal, interannual, and seasonal climatic variability of precipitation (mm), temperature (°C) and relative humidity (%) to improve water management in the state of Casanare (Colombia). Missing data and Pearson's correlation coefficient are calculated, and descriptive statistics are applied. The results show that at the decadal variability, there are no significant differences between the variables. Interannual precipitation decreases in El Niño and increases in La Niña) during phases of the ENSO event. Seasonally, the unimodal cycle dominates for precipitation, with maximum values in May-June. Relative humidity is highest in May and bimodal for temperature, having the highest values (El Niño) in the months of March-April-May and September-October-November while having the lowest values (La Niña) during December-January-February and June-July-August. It is concluded that watershed planning and management instruments should include analysis of regional climate variability. [ABSTRACT FROM AUTHOR]

This study introduces an innovative outdoor nephelometer system designed to monitor the dynamic hygroscopic behavior of aerosols in ambient air. Field measurements conducted in the Pearl River Delta region of China unveil significant roles of relative humidity (RH) swings on aerosol phase states. Highlighting the occurrence of aerosol crystallization in the afternoon followed by gradual deliquescence as RH increases, particularly when minimum afternoon RH drops below 35%, with no such behavior observed when it exceeds 40%. Emphasizing that aerosol phase states are shaped not only by RH and chemical composition but also by their RH history, illustrating that RH levels of 70% in the morning or evening may correspond to fully dissolved metastable or partially dissolved metastable states of ambient aerosols. These findings underscore the need to account for RH history when predicting aerosol phase states and have broader implications for comprehending aerosol behavior and its atmospheric impacts. Plain Language Summary: This research introduces a new device to study how tiny particles called atmospheric aerosols in the air behave when they encounter moisture. We tested it in a region of China and discovered that relative humidity fluctuations from morning to evening impact significantly on phase state of atmospheric aerosols. In the afternoon, some of the particles might become solid, like tiny crystals, and later turn into liquid gradually as humidity increases. This phenomenon occurs when the afternoon minimum relative humidity is low, below 35%, but does not take place when it exceeds 40%. Suggesting that relative humidity history matters for aerosol phase. For example, relative humidity of 70% in the morning or evening, particles may be in a liquid or semi‐liquid state. This study helps us understand phase changes of atmospheric particles and their effects on our environment. Key Points: Innovative outdoor nephelometer system was developed to monitor aerosol hygroscopic behavior in ambient airAerosol crystallization in the afternoon followed by gradual deliquescence observedRelative humidity history plays significant roles in determining aerosol phase state [ABSTRACT FROM AUTHOR]

In the marine environment, sea salt aerosol particles transition from cubic or rectangular shapes when dry to various non-spherical shapes like ellipsoids and cylinders under different humidities. The complex humidity conditions and particle morphologies pose challenges to simulating the optical scattering properties of non-spherical sea salt aerosols. This study, addressing real environmental scenarios, employs the randomly oriented T-matrix computational method to calculate the optical scattering and polarization characteristics of sea salt aerosols at a wavelength of 1.06 μm under three relative humidity conditions (50%, 80%, and 95%) and three particle morphologies (spheroid, circular cylinder, and Chebyshev particle shapes). The results show the following: (1) In terms of optical scattering properties, the greater the non-sphericity of particles under the same humidity conditions, the larger the deviation between non-spherical and spherical models. For spheroid and circular cylinder sea salt aerosols, the error in the extinction efficiency factor mainly lies within 10–30%, reaching up to 120%; the error in the asymmetry factor is primarily between 3 and 25%, with a maximum of 75%, and the error in the forward-scattering phase function is mainly within 10–60%, reaching up to 180%. Chebyshev particle-shaped sea salt aerosols exhibit smaller deviations in optical scattering properties compared to equivalent spherical models, generally within the 5–25% range. Under different humidity conditions, the scattering characteristic parameters of sea salt aerosol particles for various non-spherical models show a positive correlation with relative humidity. When relative humidity is below 70%, the optical scattering properties of differently shaped sea salt aerosols are less affected by relative humidity. Above 70% relative humidity, the optical scattering properties of sea salt aerosols of different shapes become more sensitive to changes in relative humidity. (2) Regarding polarization properties, the greater the humidity, the more significant the impact on polarization properties, and as humidity increases, sea salt aerosols with higher non-sphericity exhibit more complex changes in polarization characteristics. The differences in shapes of non-spherical models mainly affect the numerical values of polarization properties. Under the same humidity conditions, spheroid polarization characteristics are significantly different from other models. In terms of depolarization ratio for aerosols, circular cylinder sea salt aerosols show the highest depolarization ratio at various relative humidities, followed by spheroid, with Chebyshev-shaped having the least. The effect of relative humidity on the depolarization ratio varies with the scattering angle. The higher the relative humidity, the more complex the variation in the depolarization ratio with scattering angle, with more pronounced oscillations in the curve, and the less non-spherical the shape, the more intense the oscillations in the depolarization ratio curve due to humidity. In conclusion, this study calculated the optical scattering and polarization properties of sea salt aerosol particles under different relative humidities and shapes, which is of significant importance for applications like 1.06 μm laser engineering and atmospheric radiation transmission in actual marine scenarios. [ABSTRACT FROM AUTHOR]

Drying temperature, air velocity and humidity of drying medium are the three important parameters during hot air drying of fruits and vegetables. Among them, drying temperature and air velocity are positively related to drying efficiency. Relative humidity (RH) is usually used to reflect the size of the humidity or humidity content of the medium at the constant drying temperature and total pressure. However, it is still unclear on the influence mechanism of RH on drying. The manual regulation of relative humidity cannot fully meet the large-scale production, due to the low quality, drying efficiency, and high energy consumption. Therefore, this study aims to clarify the influence and control mechanism of RH on the heat and mass transfer during hot air drying of fruits and vegetables, in order to reduce the emission and loss for energy saving with high efficiency. The drying quality was optimized in the control of RH in four aspects. The low RH was used to increase the mass transfer coefficient and the evaporation of water on the surface of the material. While the high RH was to increase the convective heat transfer coefficient and the heating rate of the material. In the high RH, there was the increase in the temperature rise rate of the material, and the internal water migration, but there was the low evaporation of surface water. In the low RH, there was a low heating rate of the material and the internal water migration, but there was a high evaporation of surface water. As such, there was the coupled influence of RH on the heat and mass transfer. High RH was mainly reflected in the heat transfer, whereas, low RH was in the mass transfer. High RH was used to avoid crust formation on the surface of the material, in order to improve the rehydration for the less shrinkage rate. The honeycomb porous structure was formed and maintained on the surface of the material under the step-down dehumidification and multi-stage dehumidification drying, leading to high drying efficiency and quality. An optimal RH control was achieved using material temperature. The stage dehumidification and drying were attributed to: the relative magnitude of thermal resistance to heat transfer and internal heat conduction, and the relative magnitude of mass transfer resistance and internal mass transfer resistance during drying. The heat and mass transfer resistance depended mainly on the drying conditions, types and thicknesses of materials. The stage dehumidification and drying were suitable for the drying of this material at Bih>1 and Bim>0.1. The influence mechanism was given on the relative humidity during hot air drying of fruits and vegetables. The finding can also provide the theoretical basis and technical support to the influence and control mode of RH in the hot air drying of fruits and vegetables. [ABSTRACT FROM AUTHOR]

The population of developed nations spends a significant amount of time indoors, and the implications of poor indoor air quality (IAQ) on human health are substantial. Many premature deaths attributed to exposure to indoor air pollutants result from diseases exacerbated by poor indoor air. CO2, one of these pollutants, is the most prevalent and often serves as an indicator of IAQ. Indoor CO2 concentrations can be significantly higher than outdoor levels due to human respiration and activity. The primary objective of this research was to numerically investigate the indoor relative humidity and CO2 in cob buildings through the CobBauge prototype, particularly during the first months following the building delivery. Both in situ experimental studies and numerical predictions using an artificial neural network were conducted for this purpose. The study presented the use of a piecewise autoregressive exogenous model (PWARX) for indoor relative humidity (RH) and CO2 content in a building constructed with a double walling system consisting of cob and light earth. The model was validated using experimental data collected over a 27-day period, during which indoor RH and CO2 levels were measured alongside external conditions. The results indicate that the PWARX model accurately predicted RH levels and categorized them into distinct states based on moisture content within materials and external conditions. However, while the model accurately predicted indoor CO2 levels, it faced challenges in finely classifying them due to the complex interplay of factors influencing CO2 levels in indoor environments. [ABSTRACT FROM AUTHOR]

The Radiative‐Convective Equilibrium Model Intercomparison Project (RCEMIP) exhibits a large spread in the simulated climate across models, including in profiles of buoyancy and relative humidity. Here we use simple theory to understand the control of stability, relative humidity, and their responses to warming. Across the RCEMIP ensemble, temperature profiles are systematically cooler than a moist adiabat, and convective available potential energy (CAPE) increases with warming at a rate greater than that expected from the Clausius‐Clapeyron relation. There is higher CAPE (greater instability) in models that are on average moister in the lower‐troposphere. To more explicitly evaluate the drivers of the intermodel spread, we use simple theory to estimate values of entrainment and precipitation efficiency (PE) given the simulated values of CAPE and lower‐tropospheric relative humidity. We then decompose the intermodel spread in CAPE and relative humidity (and their responses to warming) into contributions from variability in entrainment, PE, the temperature of the convecting top, and the inverse water vapor scale height. Model‐to‐model variation in entrainment is a dominant source of intermodel spread in CAPE and its changes with warming, while variation in PE is the dominant source of intermodel spread in relative humidity. We also decompose the magnitude of the CAPE increase with warming and find that atmospheric warming itself contributes most strongly to the CAPE increase, but the indirect effect of increases in the water vapor scale height with warming also contribute to increasing CAPE beyond that expected from Clausius‐Clapeyron. Plain Language Summary: Idealized model simulations of the tropical atmosphere disagree on profiles of temperature and humidity. Here we use simple theory to understand the intermodel spread in humidity and in a measure of instability to convection (small‐scale rising motion). There is greater instability in models that are on average moister. We find that model‐to‐model variations in small‐scale turbulent mixing between cloudy and clear air cause the intermodel spread in instability. Model‐to‐model variations in the fraction of cloud water that reaches the surface as rainfall cause the intermodel spread in humidity. The instability increases substantially with warming, which is driven by a warmer and moister lower atmosphere. Key Points: A stability‐relative humidity phase space is used to diagnose theory‐implied entrainment and precipitation efficiency in RCEVariations in entrainment explain intermodel spread in CAPE but variations in precipitation efficiency explain spread in humidityIncreases in the water vapor scale height with warming lead to CAPE increases with warming that are faster than Clausius‐Clapeyron scaling [ABSTRACT FROM AUTHOR]

Ground penetrating radar (GPR) technology is used for nondestructive testing of roads. It relies on the processing and analysis of electromagnetic waves reflected due to the differences in dielectric properties encountered by electromagnetic pulses during propagation for road quality assessment and detects distresses. The moisture content of the asphalt mixture in asphalt pavement undergoes dynamic changes, affecting the pavement's relative humidity (RH). This alteration in RH has a direct impact on the dielectric properties of the asphalt mixture, thus influencing the accuracy of GPR road detection. Therefore, it is essential to quantify the relationship between RH and the dielectric properties of asphalt mixtures. This study utilized electromagnetic field theory to establish the correlation between air dielectric constant and RH. Dielectric constant tests were performed on commonly used single-phase component materials (limestone, 70# asphalt, SBS-modified asphalt) of asphalt mixtures and different types (asphalt type, asphalt-aggregate ratio, nominal maximum aggregate size) of asphalt mixtures under varying RH. The study quantified the impact of RH on the dielectric properties of asphalt mixtures and developed a CRIM optimization dielectric model that incorporates the RH effect. The research results showed that the dielectric constants of air, limestone, asphalt, and asphalt mixtures increase with the increase in RH. Specifically, the dielectric constants of air and asphalt mixtures exhibit a linear relationship with RH. Moreover, the increase in the dielectric constant of 70# asphalt with RH is greater than that of SBS-modified asphalt. Under identical conditions, reducing the impact of RH on the dielectric properties of asphalt mixtures can be achieved by increasing the asphalt-aggregate ratio, decreasing the nominal maximum particle size of the aggregates, or utilizing SBS-modified asphalt. The CRIM optimization model yielded an overall average relative error of 3.33% for calculating the dielectric constants of different types of asphalt mixtures under the influence of RH, representing at least a 1.67% improvement compared to classical models and the improved model proposed from existing literature. The research outcomes provide significant guidance for enriching and developing the fundamental theory as well as detection evaluation technology of GPR. [ABSTRACT FROM AUTHOR]

Water microdroplets (7 to 11 µm average diameter, depending on flow rate) are sprayed in a closed chamber at ambient temperature, whose relative humidity (RH) is controlled. The resulting concentration of ROS (reactive oxygen species) formed in the microdroplets, measured by the amount of hydrogen peroxide (H2O2), is determined by nuclear magnetic resonance (NMR) and by spectrofluorimetric assays after the droplets are collected. The results are found to agree closely with one another. In addition, hydrated hydroxyl radical cations (•OH-H3O+) are recorded from the droplets using mass spectrometry and superoxide radical anions (•O2 -) and hydroxyl radicals (•OH) by electron paramagnetic resonance spectroscopy. As the RH varies from 15 to 95%, the concentration of H2O2 shows a marked rise by a factor of about 3.5 in going from 15 to 50%, then levels off. By replacing the H2O of the sprayed water with deuterium oxide (D2O) but keeping the gas surrounding droplets with H2O, mass spectrometric analysis of the hydrated hydroxyl radical cations demonstrates that the water in the air plays a dominant role in producing H2O2 and other ROS, which accounts for the variation with RH. As RH increases, the droplet evaporation rate decreases. These two facts help us understand why viruses in droplets both survive better at low RH values, as found in indoor air in the wintertime, and are disinfected more effectively at higher RH values, as found in indoor air in the summertime, thus explaining the recognized seasonality of airborne viral infections. [ABSTRACT FROM AUTHOR]

In this work, the effect of low air relative humidity on the operation of a polymer electrolyte membrane fuel cell is investigated. An innovative method through performing in situ electrochemical impedance spectroscopy is utilised to quantify the effect of inlet air relative humidity at the cathode side on internal ionic resistances and output voltage of the fuel cell. In addition, algorithms are developed to analyse the electrochemical characteristics of the fuel cell. For the specific fuel cell stack used in this study, the membrane resistance drops by over 39 % and the cathode side charge transfer resistance decreases by 23 % after increasing the humidity from 30 % to 85 %, while the results of static operation also show an increase of ∼2.2 % in the voltage output after increasing the relative humidity from 30 % to 85 %. In dynamic operation, visible drying effects occur at < 50 % relative humidity, whereby the increase of the air side stoichiometry increases the drying effects. Furthermore, other parameters, such as hydrogen humidification, internal stack structure, and operating parameters like stoichiometry, pressure, and temperature affect the overall water balance. Therefore, the optimal humidification range must be determined by considering all these parameters to maximise the fuel cell performance and durability. The results of this study are used to develop a health management system to ensure sufficient humidification by continuously monitoring the fuel cell polarisation data and electrochemical impedance spectroscopy indicators. • PEM Fuel cell inlet air relative humidity regulation using a passive humidifier with fuzzy logic control. • Using EIS characteristics to quantify the effect of air relative humidity on PEMFC performance. • Air RH affects PEMFC significantly depicted by mean cell voltage and internal resistances. • Electrochemical analyses using EIS oriented algorithms to develop a health management system. [ABSTRACT FROM AUTHOR]

Improving the performance of polymer electrolyte fuel cells requires reducing the concentration overpotential at high current densities. Since liquid water accumulation in the gas diffusion layer (GDL) prevents oxygen diffusion to the catalyst layer, water management is a critical issue in fuel cell design and optimization. For such a purpose, the use of numerical simulation is desired. In the present study, a new macroscopic condensation model and a two-fluid model are developed. By using a condensation rate constant that depends on the relative humidity, the present simulation successfully predicts the liquid water content in the GDL quantitatively under a wide range of cell temperature and relative humidity conditions, which is experimentally validated using operando synchrotron X-ray radiography. The simulation also provides the state of water oversaturation. At 313 K, the relative humidity exceeds 100% extensively in the GDL except near the gas channel, while oversaturation is mitigated by higher temperatures. Thus, a simulation method incorporating finite phase change rates must improve prediction accuracy at lower cell temperatures and is expected to broaden the applicability of numerical prediction across various temperature and relative humidity conditions. • A new macroscopic condensation model and a two-fluid model are developed. • The model employs a condensation rate constant depending on the relative humidity. • The predicted liquid water content in GDL agrees well with experimental measurement. • The present model is effective under a wide range of temperature and RH conditions. • The state of oversaturation is reproduced, which is extensive at low temperature. [ABSTRACT FROM AUTHOR]

This work aims to use experimental data from thermal characterization and adsorption/desorption isotherms of two tropicals woods species (Ayous and Tali) to propose an empirical model of thermal conductivity as a function of air relative humidity. A static gravimetric method was used to determine the adsorption isotherms of Tali and Ayous at 30 °C, and 40 °C. The GAB, Henderson and Nelson models were used to predict the isotherms. Exponential models of thermal conductivity and volumetric heat capacity with air relative humidity were proposed. The influence of hysteresis phenomenum was studied on these properties. The reliability of the developed empirical correlation between thermal properties and air relative humidity was evaluated by comparing the experimental and predicted curves. The relative errors were less than 8% for both Ayous and Tali. The correlation coefficients obtained were greater than 99% for both species in adsorption and desorption. There was also an increase in the equilibrium water content of both species with the increase in water activity at constant temperature. The correlation coefficients between GAB model and sorption experimental data were lower than 99% when Ayous was subjected to a temperature of 40 °C in adsorption and Tali to a temperature of 40 °C in desorption. [ABSTRACT FROM AUTHOR]

There is no simple explanation for the spatial structure of near-surface relative humidity over land. We present a diagnostic theory for zonally and temporally averaged near-surface relative humidity (RH) over land based on energy budgets of an atmospheric column in radiative–convective equilibrium. The theory analytically relates RH to the surface evaporative fraction (EF), has no calibrated parameters, and is quantitatively accurate when compared with RH from a reanalysis, and with cloud-permitting simulations over an idealized land surface. The theory is used to answer two basic questions. First, why is RH never especially low (e.g., 1%)? The theory shows that established lower bounds on EF over land and ocean are equivalent to lower bounds on RH that preclude particularly low values, at least for conditions typical of the modern Earth. Second, why is the latitudinal profile of RH over land shaped like the letter W, when both specific humidity and saturation specific humidity essentially decline monotonically from the equator to the poles? The theory predicts that the latitudinal profile of RH should look more like that of water stored in the soil (which also exhibits a W-shaped profile) than in the air (which does not). [ABSTRACT FROM AUTHOR]

Aerosol water affects the physicochemical properties and mass concentration of organic aerosols (OA), but it is typically omitted by air quality, weather, and climate models. We compare two classes of simplified models to estimate the OA water uptake and gas–particle partitioning of organic compounds. One class uses a single‐hygroscopicity‐parameter (κ) approach while the other is based on the reduced‐complexity Binary Activity Thermodynamics (BAT) model. We show that a BAT‐based two‐dimensional volatility basis set (VBS) model always predicts a higher OA mass concentration at elevated relative humidity (RH), for example, ∼16% at 80% RH, than any variation of the κ‐based method considered—even when BAT‐VBS predicts a lower water uptake. The main reason being that the BAT‐VBS model captures variations in effective saturation mass concentration of organics (C*) with RH, a feature that other VBS methods lack. The BAT‐VBS framework offers an efficient, RH‐sensitive treatment for reduced‐complexity OA modeling. Plain Language Summary: Organic compounds in the environment are present in both the gas phase and in condensed aerosol particles when of sufficiently low volatility. The latter contributing to what is known as organic aerosol, a major component of air pollution. Water vapor is one of the most important species in the air, including due to its effect on aerosol water content as a function of relative humidity. However, the implications of absorbed water on the equilibrium distribution of organics between aerosol particles and the gas phase are neglected by most air quality, weather, and climate models. We show that capturing the organic aerosol water uptake tends to increase the mass of organics present in aerosols. Additionally, we show that commonly used approaches, even when accounting for water uptake into the organic aerosol, tend to fail to predict the complete amplification of organic aerosol mass. Our work, based on a sound thermodynamic framework, shows the importance of a feedback effect between water uptake, changing particle properties, and the subsequent uptake of additional semivolatile organics from the gas phase. Our findings are particularly pertinent to the improvement of the reduced‐complexity representation of organic aerosols in large‐scale models used for air quality and climate simulations. Key Points: 2D volatility basis set models of organic aerosol predict diverging effects of water uptake on organic aerosol mass concentrationAn efficient thermodynamic equilibrium model captures the variation of effective volatility of organics with relative humidityCommon models based on hygroscopicity parameters fail to represent water uptake feedback effects and underestimate organic aerosol mass [ABSTRACT FROM AUTHOR]

Simple Summary: Our study shows that the African citrus psyllid, a vector of Huanglongbing disease, prefers to develop at mild temperatures and is not well adapted to dry regions, where relative humidity is around or below 40%. Its life cycle is not completed or is severely delayed at temperatures above 30 °C and below 10 °C. Eggs are unable to hatch at constant temperatures below 8 °C or above 33 °C. Thus, T. erytreae establishment and spread will be maximum in regions with a temperate and humid climate, being rare in regions where dry weather conditions predominate. The African citrus psyllid, Trioza erytreae, is one of the two vectors of Huanglongbing, the most serious citrus disease worldwide. The first detection of T. erytreae in the European mainland was on the northwest of the Iberian Peninsula in 2014. Since then, the pest has spread throughout northern Spain (Galicia, Asturias, Cantabria, País Vasco) and along the western Atlantic coast of Portugal (from the Douro e Minho region to the Algarve). We conducted a series of laboratory experiments on lemon plants at different temperatures (from 8 to 34 °C) and humidity conditions (from 40 to 90%) to find out the influence of extreme temperatures and relative humidities (RHs) on the mortality, development and reproduction of T. erytreae. Our results show that temperatures above 30 °C and below 10 °C are very detrimental for nymphal development and nymphs were unable to reach the adult stage. Furthermore, eggs were unable to hatch under temperatures above 33 °C and below 8 °C. Adult mortality was highest at 34 °C and killed more than 50% of the population. We also found that relative humidity is crucial for the development and survival of T. erytreae. Nymphs were unable to reach the adult stage at an RH of 90% and 40%. Also, fecundity was significantly reduced at 90 and 40% RH, and fertility was lowest at 40% RH. Nymphal mortality was highest at an RH of 40%, which was the most detrimental humidity among all tested for the survival and development of T. erytreae. Our work concludes that T. erytreae establishment and spread will be maximum in regions with a temperate and humid climate, being rare in regions where dry and hot weather conditions predominate. [ABSTRACT FROM AUTHOR]

Measuring the relative humidity of air is an important challenge for meteorological measurements, food conservation, building design, and evaporation control, among other applications. Relative humidity can be measured with a psychrometer, which is a hygrometer composed of two identical thermometers. The bulb of one thermometer is covered by a wick soaked with water so that evaporative cooling makes it indicate a lower temperature than the dry-bulb thermometer; it is possible to determine the relative humidity from the difference between these readings. We describe both a model and an experimental setup to illustrate the principle of a psychrometer for a pedagogical laboratory. The science of psychrometry could be more broadly taught at the undergraduate level to help introduce students to aspects of measurement techniques, fluid mechanics, heat transfer, and non-equilibrium thermodynamics. [ABSTRACT FROM AUTHOR]

Photosynthetic CO2 assimilation (AN) under fluctuating light (FL) plays a critical role in plant growth and crop yield. C4 crops usually reach greater yields than C3 crops when grown in regions with low relative humidity, which might be partly due to the CO2 concentration mechanism and higher AN under FL of C4 crops. To test this hypothesis, we measured gas exchange and chlorophyll fluorescence under different changing frequencies of FL at contrasting relative air humidity (60% and 15%) for leaves of maize (Zea mays, C4) and tomato (Solanum lycopersicum, C3). In general, a more rapid changing frequency of FL would cause a larger loss in AN during shade‐sun transitions, with 20–38% in maize and 16–52% in tomato. Low relative humidity induced a larger decrease of stomatal conductance (gs) under FL in tomato than in maize, leading to a much stronger loss in AN in tomato than in maize. After transition from low to high light, AN of maize was mainly limited by gs with negligible non‐stomatal limitation, and the stomatal limitation was slightly affected by relative humidity. By comparison, low relative humidity significantly increased the stomatal limitation of AN in tomato but hardly affected non‐stomatal limitation. These results highlight the differential impact of decreasing relative humidity on dynamic photosynthesis and productivity between C3 and C4 crops. [ABSTRACT FROM AUTHOR]

In this work, a simple one-step hydrothermal synthesis of La doped SnO 2 nanocomposites was studied. The structure, morphology, specific surface area, and chemical composition were determined by XRD, SEM, BET, and XPS techniques. The gas sensing performance of SnO 2 and La/SnO 2 nanocomposites with varied La doping dosages on n-butanol gas was systematically investigated. The results manifested that under the testing environment (50 % relative humidity and 30 °C), La doped SnO 2 nanocomposite sensor presented high response (69), excellent selectivity, good repeatability and long-time stability to n-butanol gas at 160 °C. Especially, the 7 mol% La doped SnO 2 sensor displayed a 5.9 times higher response to 50 ppm n-butanol than the SnO 2 sensor. In comparison with bare SnO 2 , La doping increased the band gap value of 7 mol% La/SnO 2 nanocomposite by 6.23 %, decreased particle size by 11.83 %, and increased the oxygen defect concentration by 6.07 %. Due to the synergistic effect of the above factors, the gas sensing performance of La doped SnO 2 nanocomposites towards n-butanol gas was enhanced. Therefore, La doped SnO 2 nanocomposites might be a potential gas sensing material for monitoring n-butanol gas at relatively high humidity. [ABSTRACT FROM AUTHOR]

Understanding and accurately modeling the creep behavior of rock salt is of great interest for its relevance to geological storage of nuclear wastes, oil, and gases. Many experimental studies on the creep of salt samples are performed at a deviatoric stress above 5 MPa. The creep rates at smaller stress levels are usually estimated by extrapolating from data at higher stress levels. However, recent low-stress creep tests conducted at below 1 MPa suggest that such extrapolation can significantly underestimate the creep rate of rock salt, as the controlling micro-mechanisms are very different in low- and high-stress regimes. Meanwhile, field observations suggest that salt creep is accelerated under higher ambient relative humidity (i.e., the so-called Joffe effect). The effect of humidity on salt creep in the pressure-solution dominating low-stress regime is even less understood at present. In this context, we conducted a series of long-term creep tests at intermediate–low uniaxial stresses of 1, 3, and 5 MPa on Avery Island salt samples. In order to quantify the effect of moisture on salt creep, a combined triaxial cell and air circulation system is designed to permit control over the environmental humidity. Three relative humidity levels (33%, 55% and 77%) are selected and are achieved through the vapor equilibrium technique. Our study confirmed that the creep rate at low stress level is indeed higher than those extrapolated from high-stress creep tests. For the same deviatoric stress, higher ambient humidity produces faster steady-state creep rate of salt samples. Finally, a modified creep law that incorporates the humidity dependency is proposed and validated against the new experimental data. Highlights: The influence of ambient humidity on creep behavior of rock salt at intermediate–low stress regime was experimentally investigated. A novel experimental setup was developed to provide stable humidity- and stress-control during long-term uniaxial creep tests. Humidity-dependent scaling functions inspired by existing water retention and adsorption models were introduced in the steady-state creep model for rock salt. [ABSTRACT FROM AUTHOR]

Radioactive wastes often contain amorphous and crystalline phases, and vapor hydration can affect their durability. In this study, Cs-clinoptilolite was heated (at 1100 °C and for 2–36 h) to prepare the samples that were composed mainly of an amorphous phase (AmP) and CsAlSi5O12 (≥94%) with minor CsAlSi2O6. Six samples with an AmP/CsAlSi5O12 ratio from 26.5 to 0.1 were kept at 21 °C and 55% relative humidity, and their hydration was measured via thermogravimetry (TG) over a period of almost six years. The hydration that resulted was directly related to the AmP quantity. The increase in water content followed a logarithmic trend over time. It reached 1.95% in the AmP-richest material, while it attained only 0.07% in the most crystalline sample. The hydrolysis of the AmP led to an increase over time in the tightly bound water. Samples with an AmP of ≤19% demonstrated slightly higher durability due to the lower Cs content in the AmP. [ABSTRACT FROM AUTHOR]

The impacts of urban forest fragmentation on tropical ant foraging activity are poorly understood. The Malaysian giant ant (Dinomyrmex gigas) is among the largest ant species worldwide. Colonies of this species contribute to important ecosystem processes such as predation and nutrient cycling in the tropical forests of Southeast Asia.Here, we compared the diurnal foraging activity of D. gigas workers in urban‐fragmented and contiguous forests, and investigated how this was shaped by key environmental factors such as vegetation structure and microclimate. Specifically, we sampled ground‐foraging D. gigas workers in four urban/semi‐urban forest patches and two contiguous forests in Peninsular Malaysia across the wet and dry seasons.Surprisingly, we found that some urban forest patches, irrespective of area, supported greater foraging activity of D. gigas workers than contiguous forests. These differences in foraging activity were explained by differences in multiple stand‐level variables between urban forests patches and contiguous forests. Specifically, the abundance of foraging D. gigas workers increased with number of trees with Diamater at breast height (DBH) 5–30 cm, but it decreased with relative humidity, canopy cover, number of palms, number of shrubs and trees with DBH <5 cm.Our study highlights the importance of urban forest patches, microclimate and vegetation structure for driving the diurnal foraging activity of Malaysian giant ant. Small and relatively large forest patches were of comparable importance for the maintenance of biodiversity in urban landscapes.In the absence of landscape connectivity, reforestation is the most feasible option to restore the natural habitat of D. gigas in urban forest patches and mitigate microclimatic edge effects. [ABSTRACT FROM AUTHOR]

In greenhouses, plant growth is directly influenced by internal environmental conditions, and therefore requires continuous management and proper environmental control. Inadequate environmental conditions make plants vulnerable to pests and diseases, lower yields, and cause impaired growth and development. Previous studies have explored the combination of greenhouse actuator control history with internal and external environmental data to enhance prediction accuracy, using deep learning-based models such as RNNs and LSTMs. In recent years, transformer-based models and RNN-based models have shown good performance in various domains. However, their applications for time-series forecasting in a greenhouse environment remain unexplored. Therefore, the objective of this study was to evaluate the prediction performance of temperature, relative humidity (RH), and CO2 concentration in a greenhouse after 1 and 3 h, using a transformer-based model (Autoformer), variants of two RNN models (LSTM and SegRNN), and a simple linear model (DLinear). The performance of these four models was compared to assess whether the latest state-of-the-art (SOTA) models, Autoformer and SegRNN, are as effective as DLinear and LSTM in predicting greenhouse environments. The analysis was based on four external climate data samples, three internal data samples, and six actuator data samples. Overall, DLinear and SegRNN consistently outperformed Autoformer and LSTM. Both DLinear and SegRNN performed well in general, but were not as strong in predicting CO2 concentration. SegRNN outperformed DLinear in CO2 predictions, while showing similar performance in temperature and RH prediction. The results of this study do not provide a definitive conclusion that transformer-based models, such as Autoformer, are inferior to linear-based models like DLinear or certain RNN-based models like SegRNN in predicting time series for greenhouse environments. [ABSTRACT FROM AUTHOR]

Quinoa is of great interest because it is cold- and drought-resistant; however, little research has been performed on quinoa under high relative humidity (RH) stress. In this study, quinoa seedlings of a highly HR-resistant variety ("Dianli-439") and a sensitive variety ("Dianli-969") were subjected to morphological and physiological measurements and metabolome and transcriptome analyses to investigate their response to high RH stress. In total, 1060 metabolites were detected, and lipids and flavonoids were the most abundant, with 173 and 167 metabolites, respectively. In total, 13,095 differentially expressed genes were identified, and the results showed that abscisic acid, auxin, and jasmonic-acid-related genes involved in plant hormone signaling may be involved in the response of quinoa seedlings to high RH stress. The analysis of the transcription factors revealed that the AP2/ERF family may also play an important role in the response to high RH stress. We identified the possible regulatory mechanisms of the hormone signaling pathways under high RH stress. Our findings can provide a basis for the selection and identification of highly resistant quinoa varieties and the screening of the metabolite-synthesis- and gene-regulation-related mechanisms in quinoa in response to RH stress. [ABSTRACT FROM AUTHOR]

To understand and study the climate, there is a need to create high‐quality climatological databases. At the Climate Department of the OMSZ (Hungarian Meteorological Service), we use MASH (Multiple Analysis of Series of Homogenization) and MISH (Meteorological Interpolation based on Surface Homogenized Data Basis) software to produce a spatially and temporally representative database. However, these systems were developed for daily and monthly data series, so some improvements were required when applying them to hourly relative humidity data. The problem relates to the issue of the daily cycle. The aim of this article is to show how the data set of hourly values of the relative humidity measurements was prepared. To construct the grid point database, a homogenized data set of 41 stations for the period 1961–2020 was used; this was then interpolated into to a regular grid with a resolution of 0.1°. At the end of the study, the hourly and daily data gridded series are compared. [ABSTRACT FROM AUTHOR]

A relative humidity (RH) sensor based on in-fiber Michelson interferometer (MI) is proposed, which consists of a short piece of graded-index multimode fiber (GIMMF) followed by a 2-core fiber (2CF), whose end face is terminated by a thick aluminum film. The GIMMF excites cladding modes into the pigtail 2CF via the mismatched-core splicing interface. The core-cladding modes are reflected back by the aluminum film and recoupled to the core of lead-in SMF through the GIMMF. A well-defined interference pattern is obtained as the result of core-cladding mode interference. The experimental results show that a configuration with a 10 mm pigtail 2CF at a wavelength of 1552.78 nm has a good linear response to relative humidity with the sensitivity of – 0.044 dB/%RH in the range of 35–95%RH. Meanwhile, the selected monitoring peak provides a better temperature sensitivity of 65 pm/℃ in the range of 35 –85 ℃. In addition, the aluminum film is manufactured by physical vapor deposition (PVD), which greatly enhances the compactness of the film and improves the contrast of the interference fringes; the manufacturing method has high repeatability. [ABSTRACT FROM AUTHOR]

This article is to study the criteria of dehydration model, and to establish the Brixter index. Coffee cherries (Coffea arabica L. var. catimor) were selected from two different farms in Pangkhon village, Chiang Rai province, which are in the northern part of Thailand: Farm A, and Farm B. The low air temperatures (18–30 °C) and low relative humidities (65–30%) technique (LTLH) was gradiently applied, to dehydrate the coffee bean, leading to higher sugar concentration. The applicability of the various measurements, such as physicochemical properties, dehydration kinetic, Brix boosting parameters, and their correlations were investigated. The level of soluble solids (°Brix) and acid concentrations in coffee samples were analyzed, to determine the °Brix/acid and oBrix*pH2 ratios. The qualities of coffee cherries changes depending on the decreasing level of moisture content during the dehydration process. The °Brix degree reveals that by the end of the dehydration process, the sugar concentration of coffee cherries has increased by 1.5 times that of its initial. The °Brix/acid, and oBrix*pH2 ratios highly correlated to the amount of soluble solids (r2 = 0.923 and 0.972, respectively) within coffee cherries. The most suitable timing to select dehydrating coffee cherries for the fermentation process is when the coffee cherries have attained °Brix/acid ratio of > 10 to 33, and oBrix*pH2 ratio of > 400 to 850. These ratios can be used as an efficient instrument to determine the optimum Brix boosting stage of coffee cherry in the LTLH system. [ABSTRACT FROM AUTHOR]

Simple Summary: Relative humidity, as a significant environmental factor, has an important effect on the growth of ducks. This study elucidates the impact of different humidity environments on the production performance and muscle quality of ducks. The research findings demonstrate that ducks exhibit better growth and meat quality at 74% humidity; however, when environmental humidity exceeds 81%, production performance and meat quality plummet sharply. This study aimed to investigate the effects of different humidity levels on the growth performance, slaughter performance, and meat quality of Pekin ducks through the artificial control of humidity, and to identify the suitable environmental humidity for Pekin duck growth. A completely randomized single-factor design was employed, selecting 144 newly hatched male Pekin ducks with healthy and similar BW (body weight) (60.92 g ± 4.38). These ducks were randomly assigned to four groups (A (RH (relative humidity) = 60%), B (RH = 67%), C (RH = 74%), D (RH = 81%)), with 12 ducks and 3 replicates in each group. The ducks were raised in a climate-controlled room for 42 days with ad libitum access to feed and water. BW and feed intake were measured every 3 days, and slaughter performance and meat quality were assessed at 42 days. There was no significant difference in the ADG (average daily gain) from 1 to 21 days (p > 0.05). The ADFI (average daily feed intake) of Group D was significantly lower than that of Groups A, B, and C (p < 0.05), with no significant differences between Groups A, B, and C (p > 0.05). At 42 days, the BW, ADG, and ADFI of Groups A and C were significantly higher than those of Group D (p < 0.05), with no significant differences among Groups A, B, and C (p > 0.05). Group C had a significantly higher breast muscle weight, breast muscle ratio, liver weight, and liver index than Groups B and D (p < 0.05), with no significant differences between Groups A, B, and D (p > 0.05). The meat shear force in Group C was significantly lower than that in Groups A, B, and D (p < 0.05). The L* (brightness) of Group C was significantly lower than that of Group A (p < 0.05), and the a* (redness) value of Group C was significantly higher than that of Groups A and B (p < 0.05), with no significant difference compared to Group D (p > 0.05). Group B had a significantly higher cooking loss than Groups A, C, and D (p < 0.05), with no significant differences among Groups A, C, and D (p > 0.05). Under 26 °C conditions, Pekin ducks perform best in terms of the production performance and feed efficiency, with high-quality meat, especially when reared at 74% humidity. [ABSTRACT FROM AUTHOR]

Nitrate has become the primary inorganic compound in urban aerosol particles, but its effects on particle phase state, which is crucial in multiphase chemistry, remains largely unknown. Herein, particle rebound measurements were conducted to explore the relationship between the liquid–phase–transition threshold relative humidity (RHthreshold) and the inorganic compounds mass fraction in dry particles (Finorg). Results revealed negative correlations between RHthreshold and Finorg, with more nitrate leading to lower RHthreshold. Even with RH < 20%, particles with ∼50% nitrate mass fraction remained in non‐solid state. Taking Beijing as an example, decreases were observed in RHthreshold from 64% in 2015 to below 53% nowadays during the moderate‐pollution periods (PM2.5 = 35–75 μg/m3) due to an enhanced nitrate fraction. This allowed urban aerosol particles to exist in liquid state at lower RH, and consequently, kinetic limitation by bulk diffusion in nitrate‐dominated particles might be negligible, making them key seeds for secondary aerosol formation through multiphase reactions. Plain Language Summary: The phase state of aerosol particles plays a crucial role in the mass‐transfer processes between gas and particles, which is essential for determining particle mass concentration. Investigating the characteristics of the aerosol phase state is crucial for comprehending the mechanisms behind secondary particle formation and improving air quality. Currently, the chemical composition of urban aerosol particles has shown notable changes. The mass fraction of inorganic components has increased, with nitrate emerging as the dominant inorganic component. However, the impacts of these changes on the phase state of urban aerosol particles remain largely unknown. This study demonstrates that particles with a higher mass fraction of inorganic compounds, particularly nitrate, tend to exist in a liquid state. Consequently, an increased nitrate fraction allows urban aerosol particles to exist in a liquid state at lower relative humidity levels. These findings suggest that changes in the phase state of particles due to changes in chemical properties in urban aerosol particles should be considered to accurately gauge the mass‐transfer processes and promote the air quality improvements in urban cities. Key Points: Particles with more inorganic compounds, particularly nitrate, can exist in a liquid state at lower relative humidity levelsParticles with normalized aerosol liquid water content larger than 0.3 exist in a liquid stateNitrate‐dominated particles can serve as key seeds where secondary aerosol formation can occur via multiphase reactions [ABSTRACT FROM AUTHOR]

Polyvinyl alcohol (PVOH) exhibits outstanding gas-barrier properties, which favor its use as a biodegradable, high-barrier coating on food-packaging films, possibly in combination with modified atmospheres. Nonetheless, its high sensitivity to water can result in a severe loss of barrier properties, significantly limiting its applications with fresh foods and in high-humidity conditions. In this work, the water vapor (PWV) and oxygen permeability (PO2) of high-barrier biodegradable films with PVOH/PLA + wax double coatings were extensively characterized in a wide range of relative humidity (from 30 to 90%), aimed at understanding the extent of the interaction of water with the wax and the polymer matrices and the impact of this on the permeation process. What is more, a mathematical model was applied to the PWV data set in order to assess its potential to predict the permeability of the multilayer films by varying storage/working relative humidity (RH) conditions. The carbon dioxide permeability (PCO2) of the films was further evaluated, and the corresponding permselectivity values were calculated. The study was finally augmented through modified atmosphere packaging (MAP) tests, which were carried out on double-coated films loaded with 0 and 5% wax, and UV-Vis analyses. The results pointed out the efficacy of the PLA + wax coating layer in hampering the permeation of water molecules, thus reducing PVOH swelling, as well as the UV-shielding ability of the multilayer structures. Moreover, the MAP tests underlined the suitability of the double-coated films for being used as a sustainable alternative for the preservation of foods under modified atmospheres. [ABSTRACT FROM AUTHOR]

The aim of this paper is to determine the influence of relative humidity on the comfort and electrical resistance properties of textile laminates in order to predict possible changes in footwear protection levels. Four textile laminates of different structure and fibre nature were selected for the study. It was determined that water vapour absorption of textile laminates strongly depends on the humidity of the storage environment. The absorption ability of laminates increases about 1.8 - 3 times as relative humidity increases from 65 % up to 95 %. The degree of increase depends on the textile laminate structure and the nature of the materials layers. The electrical properties of protective footwear can be influenced by the structure, thickness, relative humidity, and voltage of textile laminates. For textile laminates composed of natural and synthetic fibres and polymer foam as insulators, the resistivity increases with the thickness of the synthetic fibre and polymer layer. At low voltage (U = 100 V), the textile laminates tested became insulating materials, as the electrical resistivity exceeded the threshold values for antistatic materials in all relative humidity ranges. At high voltage (U = 500 V) the electrical resistivity of textile the laminates drops dramatically when the relative air humidity increases and the level of protection of the laminates depend on the amount of moisture absorbed and the nature of the layer materials. The laminates possessed insulating properties in environments of up to 65 % relative humidity. In a high humidity of the environment, the insulating properties of textile laminates turned to antistatic, except for laminate without a polymeric membrane, which became conductive. [ABSTRACT FROM AUTHOR]

Relative humidity is a crucial parameter for various agricultural and engineering applications and atmospheric dynamics; hence its accurate and reliable estimation is essential. This study aims to predict monthly relative humidity by means of the artificial neural networks (ANNs) method using neighbouring data in Sivas Province, Turkey. Nineteen years (2000–2018) monthly mean relative humidity data of five measurement stations was used for ANN analysis. The prediction accuracy of the ANN models was evaluated with the coefficient of determination (R2), mean absolute error (MAE), mean absolute percentage error (MAPE) and root mean squared error (RMSE). Contour plot maps were also generated for visual comparison. R2, MAE, MAPE and RMSE values ranged between 0.952–0.965, 1.916–2.586, 3.422–4.974 and 2.472–3.391, respectively. The results showed that the ANN method provided satisfactory predictions for relative humidity. [ABSTRACT FROM AUTHOR]

The relationship of cirrus clouds and areas of increased relative humidity in the upper troposphere with symmetric instability developing on the subtropical (anticyclonic) side of jet streams are explored. Theoretical arguments are supplemented by case studies related to the Northern and Southern hemispheres. Using satellite images of cirrus clouds and reanalysis data, the values of the vertical eddy viscosity, which compensates for the inviscid growth of disturbances in case of symmetric instability, are estimated. At the levels of 250 and 200 hPa, a significant correlation between high relative humidity and potential vorticity characteristic of symmetric instability is confirmed. [ABSTRACT FROM AUTHOR]

Blueberries are prone to dehydration during storage. Firmness is one of the most critical quality attributes associated with this period, with the loss of water from the fruit representing the most significant limitation for the fresh market. Therefore, one of the great challenges is maintaining the quality characteristics of the fruit in shipments by sea, which can take up to 60 days when sent from the southern hemisphere to the northern hemisphere. The random arrangement of each fruit within a packaging unit (different proportions of the stem scar and cuticular surface exposed to the environment) represents an essential source of variation in the prediction of softening during the storage period. A special device, referred to as a dangler for accelerated dehydration (DAD), was designed to expose nearly the entire fruit surface to the environment and determine the impact of factors such as relative humidity and the role of the stem scar and cuticle on fruit water loss. Consequently, to evaluate the ability of DADs to find differences in fruit dehydration, blueberries sampled at early, peak, and late harvest dates were placed in DADs and exposed to three controlled levels of relative humidity (30%, 65%, and 96% relative humidity; 1.2 ± 0.7°C) for 10 days. Berries within the DADs were untreated, immersed in hexane for 5 seconds to remove bloom, painted with quick-drying nail polish on the pedicel end to seal the stem scar or immersed in hexane for 5 seconds, and painted with quick-drying nail polish on the pedicel end. At each harvest, fruit weight loss was significantly affected by the fruit and RH treatments, as well as the interaction between them. A regression analysis of the control treatment indicated that water loss at lower relative humidities occurred faster in fruit from the first harvest. The results reveal that DADs can be used to characterize preharvest and postharvest stimuli at an individual level and within a short time (10 days). Blueberries are prone to dehydration during storage. Firmness is one of the most critical quality attributes associated with this period, with the loss of water from the fruit representing the most significant limitation for the fresh market. Therefore, one of the great challenges is maintaining the quality characteristics of the fruit in shipments by sea, which can take up to 60 days when sent from the southern hemisphere to the northern hemisphere. The random arrangement of each fruit within a packaging unit (different proportions of the stem scar and cuticular surface exposed to the environment) represents an essential source of variation in the prediction of softening during the storage period. A special device, referred to as a dangler for accelerated dehydration (DAD), was designed to expose nearly the entire fruit surface to the environment and determine the impact of factors such as relative humidity and the role of the stem scar and cuticle on fruit water loss. Consequently, to evaluate the ability of DADs to find differences in fruit dehydration, blueberries sampled at early, peak, and late harvest dates were placed in DADs and exposed to three controlled levels of relative humidity (30%, 65%, and 96% relative humidity; 1.2 ± 0.7°C) for 10 days. Berries within the DADs were untreated, immersed in hexane for 5 seconds to remove bloom, painted with quick-drying nail polish on the pedicel end to seal the stem scar or immersed in hexane for 5 seconds, and painted with quick-drying nail polish on the pedicel end. At each harvest, fruit weight loss was significantly affected by the fruit and RH treatments, as well as the interaction between them. A regression analysis of the control treatment indicated that water loss at lower relative humidities occurred faster in fruit from the first harvest. The results reveal that DADs can be used to characterize preharvest and postharvest stimuli at an individual level and within a short time (10 days). [ABSTRACT FROM AUTHOR]

One of the vital climatic parameters with significant roles in many natural phenomena is wind. The importance of wind cannot be overemphasized due to its role as a source of renewable energy. The understanding of wind is of great importance particularly for the purpose of prediction and management of severe weather events. However, wind as a climatic parameter depends on relative humidity and temperature as well as other weather parameters and several statistical approaches such as time series analysis, extreme value analysis and spatial analysis have been used to analyze wind speed data. This study uses the kernel density method in analyzing wind speed in Ughelli, Delta State and its connection with relative humidity and temperature using the Gaussian kernel function for a period of five consecutive years from 2018 to 2022. The performance measure employ is the asymptotic mean integrated squared error (AMISE) with the Pearson R test that measures the strength of the relationship that exists between parameters. The results of the investigation with regards to the AMISE shows that 2018 recorded best performance with wind speed and relative humidity while 2021 recorded best performance for wind speed and temperature but 2019 recorded unsatisfactory outcomes for wind speed and the two parameters. This implies that human activities that depend on these parameters for their performance did best in 2018 and 2021 respectively. Furthermore, in terms of connectivity, wind speed and relative humidity are negatively correlated in 2018 and 2022 but positively correlated in 2019, 2020 and 2021 while wind speed and temperature are negatively correlated which implies that as temperature increases, wind speed decreases. [ABSTRACT FROM AUTHOR]

There are no systematic approaches available in current specialist literature when it comes to the optimization of the process of drying out hardwood species of wood, such as birch, aspen, or black alder, all of which find industrial uses in Estonia. In order to investigate the drying of these three hardwood species, this paper has made use of an experimental and theoretical drying optimization methodology which was developed previously for pine sapwood within the framework of the EIC Grant No. 16200 project. The same methodology was used to determine the critical diffusion coefficient and corresponding critical relative humidity levels (RH) in relation to the surrounding air, with those levels being important from the point of view of drying optimization, and calculating those levels separately for each species of hardwood. For alder it was found that the critical diffusion coefficient is Dcr = 36.57 * (10−4 mm2 s−1), while for aspen the figure was Dcr = 30.71 * (10−4 mm2 s−1), and for birch it was Dcr = 16.35 * (10−4 mm2 s−1). It was found that the time dependencies for the total deformation of different tree species tend to differ considerably, although the same drying regime was used for all of those tree species which were incorporated into the experiments. [ABSTRACT FROM AUTHOR]