High Humidity Environment Research Articles

Continuous Core Body Temperature Monitoring for Heatstroke Alert via a Wearable In-Ear Thermometer.

Heatstroke, a global concern exacerbated by climate change, poses significant health risks, potentially leading to multiorgan damage and fatalities. Core body temperature (CBT) is a critical and precise indicator of heatstroke, and its continuous monitoring could serve as a pivotal tool for early detection. Traditional CBT measurements, often invasive (e.g., surgical intubation, rectal or oral placement), and disrupt daily activities, whereas existing wearable devices predominantly measure skin temperatures which is susceptible to ambient environment, thus unreliable for heatstroke alert. To overcome these limitations, this study introduces an innovative in-ear wearable device to measure CBT via the cochlea, which allows for accurate CBT monitoring and timely heatstroke alerts during activities in high-temperature and high-humidity environments. The device comprises a negative temperature coefficient (NTC) thermometer integrated into a flexible precision circuit (FPC), a compact Bluetooth module, an 8 mA h micro battery, and a biocompatible, low-stimulus silica gel casing. With dimensions of 27 mm × 18 mm and a maximum in-ear diameter of 5 mm, weighing just 1.3 g, the device offers high portability and comfort, with a continuous operational lifespan of at least 24 h postcharging. A complementary software system facilitates continuous CBT monitoring, heatstroke alerts, and device management. Preliminary human trials demonstrate the device's accuracy in CBT measurement, rivaling that of rectal thermometry, and superior to the performance of surface body temperature measurement at different body parts. Long-term experiments affirm the device's efficacy in detecting rapid CBT escalations, enabling timely preventive measures against heatstroke.

Preparation and initial condensation characteristics of superhydrophobic coating based on nano-SiO2 particles

Superhydrophobic surfaces can effectively inhibit the growth of droplets and reduce attachment, thus inhibiting the formation of frost. In this paper, using dimethyldimethoxysilane-modified silica nanoparticles, a superhydrophobic coating with a contact angle of 165.73 ± 1° and a rolling angle of 2 ± 1° was successfully prepared by the secondary spraying method, and the chemical composition of the substrate and the surface morphology of the coating were characterized by means of FT-IR, EDS, and SEM. A visualization test rig was constructed to investigate the condensation droplet growth characteristics on the superhydrophobic surface across various tilt angles (0°to 90°), cold surface temperatures (-1 ℃ to 5 ℃), and humidity levels (45% to 75%). The experimental results revealed that as the tilt angle increases, the forces acting on the condensed droplets change, resulting in a higher frequency of droplet merging, jumping, and slipping. Furthermore, a decrease in cold surface temperature accelerates the growth of condensed droplets. Under varying humidity conditions, droplets on the superhydrophobic surface nucleate and grow more rapidly in high humidity environments, where they exhibit a larger coverage area despite having a relatively small mean radius.

Pore Chemical Modification of Bimetallic Coordination Networks for Coal-Bed Methane Purification under Humid Conditions.

The recycling of low-concentration coal-bed methane (CBM) is environmentally beneficial and plays a crucial role in optimizing the energy mix. In this work, we present a strategy involving pore chemical modification to synthesize a series of bimetallic diamond coordination networks, namely CuIn(ina)4, CuIn(3-ain)4, and CuIn(3-Fina)4 (where ina = isonicotinic acid, 3-ain = 3-amino-isonicotinic acid, and 3-Fina = 3-fluoroisonicotinic acid). Among these, the amino-functionalized CuIn(3-ain)4 exhibits excellent CH4 adsorption capacity (1.71 mmol g-1) and CH4/N2 selectivity (7.5) due to its optimal pore size and chemical environment, establishing it as a new benchmark material for CBM separation. Dynamic breakthrough experiments confirm the exceptional CH4/N2 separation performance of CuIn(3-ain)4. Notably, CuIn(3-ain)4 demonstrates excellent stability under wet conditions and maintains outstanding separation performance even in high-humidity environments. Additionally, theoretical simulations provide valuable insights into how selective adsorption performance can be fine-tuned by manipulating the pore size and geometry. Regeneration tests and cycling evaluations further underscore the remarkable potential of CuIn(3-ain)4 as a highly efficient adsorbent for the separation of CBM.

Dual-effect doped triboelectric nanogenerator and its stable energy harvesting and sensing in high humidity environment

Dual-effect doped triboelectric nanogenerator and its stable energy harvesting and sensing in high humidity environment

Lignin-reinforced eutectogel with environmentally stability for high-performance human multi-functional sensor

Intrinsic environmental instability of hydrogels has limited their practical applications as durable flexible sensors in human life. In this study, a bio-based eutectogel (BEG) with environmental tolerance was designed via deep eutectic solvent (DES), thioctic acid (TA) and lignin. Benefit from self-ring-opening polymerization of TA monomer in the ethanol and the lignin acting as free radicals, the BEG was fabricated through efficient cast-drying method. The dynamic interaction formation between DES and TA polymer network was revealed by using in-situ infrared spectroscopy during the ethanol evaporation process. The introduction of lignin not only improve the mechanical properties of the eutectogels, but also endow the BEG with moisture tolerance by activating self-aggregated dense hydrophobic layer on the surface while in high humidity environment. This bio-based eutectogels with non-volatility, board range operating temperature and proper self-adhesion could serve as long-term stable temperature-strain dual sensor with high sensitivity (GF = 1.17, TCR = 4.26 %/K) and rapid response behavior (373 ms). Furthermore, the biocompatible BEG was validated for recording human physiological signals over extended period with performance comparable to commercial hydrogel electrodes. This strategy could broaden the range of making durable stretchable eutectogels in human healthcare monitoring.

Dual spatial region flexible chlorine based ionic hypercrosslinked polymer synergistically adsorb formaldehyde and carbon dioxide

Efficient adsorption and purification of low concentration volatile organic compounds (VOCs) and carbon dioxide (CO2) mixture in high-humidity environments remain a daunting challenge for researchers. In this study, a dual spatial region synergistic adsorption strategy was proposed to achieve synchronous and efficient capture of formaldehyde and CO2 on flexible chlorine (Cl) based ionic hypercross-linked polymer (Cl-IHCP). Through the ordered self-assembly of ionic monomers, the array-distributed free Cl, terminal Cl, and pyrrole nitrogen (N) sites were integrated into the skeletal network of Cl-IHCP and formed ultra-microporous environment with two different adsorption regions. Different adsorption regions exhibited varying adsorption affinities for formaldehyde and CO2 molecules on three sites, thereby weakening their competitive adsorption and achieving high adsorption for both. Besides, the strong binding force of formaldehyde and CO2 molecules in different regions makes the skeleton-responsive swelling of Cl-IHCP, and created new adsorption microenvironments for the other adsorbate. This manner considerably enhanced the adsorption capacity of Cl-IHCP for formaldehyde and CO2 in mixed-component, increasing by approximately 45% and 70% respectively compared to single component formaldehyde and CO2. These fascinating properties enabled Cl-IHCP to synergistically adsorb formaldehyde and CO2 mixtures in high humidity environments. This study innovatively proposed a simple and cost-effective strategy for removing VOCs and CO2 under high humidity, providing a feasible solution for green air purification technology.

Thermodynamic Performance and Lifetime Prediction Model of High-Voltage Transmission Lines in High Temperature and High Humidity Environments

Thermodynamic Performance and Lifetime Prediction Model of High-Voltage Transmission Lines in High Temperature and High Humidity Environments

Stress Corrosion Behavior of MIG Welded Joints of 6082-T6 Aluminum Alloy at Different Temperatures

6082-T6 aluminum alloy is a commonly used aluminum alloy material in the field of rail transit because of its good molding properties, high mechanical properties, excellent corrosion resistance and weldability. In the high temperature and humid environment, the temperature change is bound to affect the stress corrosion resistance of the aluminum alloy and their welded joint. However, the influence mechanism of temperature on its stress corrosion resistance has not been explained in the existing research. In this paper, the mechanical properties and stress corrosion behaviors of melt-inert gas welded (MIG) 6082-T6 aluminum alloy welded joints were systematically studied under various temperatures condition. Results indicated the temperature scarcely affected stress corrosion cracking susceptibility index (PSCC) of base metal, while significantly affected the welded joint and higher temperature caused lower PSCC. After slow strain rate tensile test, a corrosion layer was formed, which was a typical brittle-toughness mixed failure, and the degree of brittleness increased with the increasing of temperature. Electrochemical analysis showed that corrosion resistance of the joint slightly decreased due to aluminum alloy accelerated dissolution caused by increasing of temperature. The proposed research will provide a theoretical basis for solving aluminum alloys used in rail transit, ship accessories and other industrial fields.

Amidinopyridine Ion Docking in Crown Ether Cavity to Modulate the Top Interface in Inverted Perovskite Solar Cells

AbstractThe formation of electric dipoles at the buried interface through self‐assembled molecules is crucial for minimizing non‐radiative recombination and improving the efficiency of inverted perovskite solar cells. However, creating dipoles at the upper interface has seldom been reported in the literature, primarily due to the scarcity of suitable n‐type organic passivants, film sensitivity of perovskite, and chemisorption issues. In this study, a novel bimolecular host–guest strategy is proposed utilizing the cavity of crown ether as the host and the ammonia ion as the guest. The ion‐docking phenomenon is thoroughly examined through a comprehensive range of experimental characterizations and theoretical analyses, instilling confidence in the robustness of the findings. These findings demonstrate that the host–guest electrostatic interlocking induces an electric dipole at the perovskite surface, which facilitates electron extraction and prevents hole recombination. As a result, a power conversion efficiency of 25.25% is achieved with minimal photovoltage and non‐radiative recombination losses. The target devices also exhibited superior long‐term stabilities under high humid and high temperature environments.

Textile-Based TENG Woven with Fluorinated Polyimide Yarns for Motion and Position Monitoring.

Polyimide-based triboelectric nanogenerators (TENGs) capable of energy harvesting in harsh environments (high temperature and high humidity) have been extensively studied. However, most polyimide-based TENGs have the disadvantages of poor air permeability and poor softness. In this study, a core-shell yarn with good air permeability, softness, and high electric output performance was successfully prepared by conjugate electrospinning. FEP-doped FPI and nickel-plated aramid yarn were employed as the shell and core materials, respectively. Due to the unique hierarchical porous structure and fluorinated functional group modification, the yarns exhibit excellent output performance (maximum open-circuit voltage is 22.7 V per length of 10 cm) compared to traditional polyimide yarns. The textile woven with this yarn has good high-temperature resistance, antifouling, waterproof, and self-cleaning performance, and still maintains an output performance of about 80% under 99% relative humidity. Moreover, this textile-based TENG has no significant attenuation after 10,000 cycles, showing good stability and durability. Finally, the TENG based on the intelligent fire suit is designed, which can be used for the movement and position monitoring of firefighters in high-temperature and high-humidity environments. This fluorinated polyimide yarn prepared in this study provides a promising solution for the development of self-powered sensors capable of monitoring the movement status and position of firefighters in high-temperature and high-humidity environments.

Humidity-Activated Ammonia Sensor Based on Carboxylic Functionalized Cross-Linked Hydrogel.

Owing to its extensive use and intrinsic toxicity, NH3 detection is very crucial. Moisture can cause significant interference in the performance of sensors, and detecting NH3 in high humidity is still a challenge. In this work, a humidity-activated NH3 sensor was prepared by urocanic acid (URA) modifying poly (ethylene glycol) diacrylate (PEGDA) via a thiol-ene click cross-linking reaction. The optimized sensor achieved a response of 70% to 50 ppm NH3 at 80% RH, with a response time of 105.6 s and a recovery time of 346.8 s. The sensor was improved for response and recovery speed. In addition, the prepared sensor showed excellent selectivity to NH3 in high-humidity environments, making it suitable for use in some areas with high humidity all the year round or in high-humidity areas such as the detection of respiratory gas. A detailed investigation of the humidity-activated NH3-sensing mechanism was conducted using complex impedance plot (CIP) measurements.

EIS Method to Study the Corrosion Resistance of Three Arc Spraying Composite Coatings in 3.5% NaCl Solution

To determine the sealing system of arc-spraying aluminum coating for steel structures in high humidity and harsh environments, electrochemical impedance spectroscopy (EIS) was used to study the corrosion resistance and matrix protection of three arc-sprayed aluminum /organic composite coatings in 3.5% NaCl solution. The results indicated that during the 660-day soaking experiment, the coating capacitance of the epoxy-sealing paint system was consistently lower than that of the phosphating primer system and the nano-sealing primer system. The coating resistance showed a decreasing-increasing-decreasing trend but remained above the level of 105 Ω· cm2, and it was higher than the other two systems. The coating reaction resistance remained above 107 Ω· cm2 throughout the entire experimental period, and in the later stage of the experiment, it was 2-3 orders of magnitude higher than the other two systems. It showed that the epoxy sealer system has better shielding performance and corrosion resistance. The protective process of arc-spraying composite coating on the substrate can be divided into four stages: water penetration of organic sealing coating, contact of aluminum coating with medium, formation of shielding layer by corrosion products of aluminum coating, and penetration of corrosion products of aluminum coating to seal pores of organic sealing coating.

The Participation of Trehalose Metabolism in Response to High-Humidity Stress in Megoura crassicauda (Hemiptera: Aphididae)

In the context of climate change, characterized by an increase in average precipitation, agricultural pests have demonstrated enhanced adaptability to high humidity and other challenging environmental conditions, thereby intensifying the need for effective prevention and control measures. Among these pests, Megoura crassicauda (Hemiptera: Aphididae) represents a significant threat to both crop yield and quality. The aim of this study was to investigate the physiological behavioral changes and the regulatory mechanisms of trehalose metabolism in M. crassicauda under conditions of high-humidity stress. Additionally, we sought to explore the survival strategies and water regulation mechanisms employed by this insect, with the goal of identifying new biological targets for its management. The findings indicated that, despite an increase in environmental humidity, there was no significant difference in the survival rate of M. crassicauda. However, a reduction in developmental duration and reproductive capacity was observed. Increased humidity correlated with elevated trehalose levels and decreased glycogen content. Notably, although the relative expression levels of trehalase (TRE) and Trehalose-6-phosphate synthase (TPS) were downregulated, Trehalose-6-phosphate phosphatase (TPP) expression was upregulated. These results suggest that high humidity environments significantly influence the growth, development, and trehalose metabolism of M. crassicauda. It appears that adaptations to high-humidity conditions in M. crassicauda are facilitated by modulations in the types and distribution of sugars within their bodies, achieved through alterations in the expression of genes associated with trehalose metabolism. In summary, the results of this study indicate that high humidity significantly affects the development and sugar metabolism of M. crassicauda. These changes may represent one of the potential mechanisms underlying its environmental adaptation and migration. This insight provides valuable assistance for predicting the occurrence and migration of the pest M. crassicauda.

Programmable anisotropic soft matrix enabling robust active waveguide film

In soft matrix, liquid crystals (LCs) enable low-temperature integration of multiple optical modules, owing to their remarkable programmability and anisotropicity. However, achieving efficient coupling of light source to waveguide remains challenging, primarily due to their refractive index mismatches and alignment deviations. Herein, we developed a robust waveguide film with an integrated active light source, utilizing a laser-dye-doped LC soft matrix, where efficient coupling is achieved by precisely controlling the LC alignment and careful positioning of the external pump spot to induce amplified spontaneous emission within the waveguide. This active waveguide film provides efficient light conduction with optical loss coefficients as low as 0.08 dB/mm. The special design LC arrangement in waveguide enables the manipulation of light propagation direction such as linear propagation and 180° turns. Furthermore, a four-channel equal-power splitter is established for multi-channel light output. This robust active waveguide film device demonstrates remarkable stability under high temperatures, humidity, and harsh chemical environments, along with excellent fatigue resistance. This study lays a solid foundation for the development of optical chips optimized for programmable integrated photonic systems.

Cooling Performance of TiO2-Based Radiative Cooling Coating in Tropical Conditions.

The cooling power of radiative cooling (RC) coatings depends not only on the radiative properties of the coating but also on environmental variables. In tropical environments, the cooling performance of RC coatings deteriorates due to high humidity and high solar radiation. Previous studies focused on developing high solar-reflective coatings to achieve subambient cooling in tropical environments. However, these coatings have not demonstrated the ability to be used at a large scale, mainly due to their high cost or less durability. Herein, we test an RC paint coating composed of TiO2 and polydimethylsiloxane (PDMS) in three different cities with high and moderate humidity levels. Though a significant reduction in the internal temperature of an RC paint-coated aluminum (Al) box is observed, compared to an uncoated Al box, in both high and moderate humidity environments, subambient cooling is not achieved. A comprehensive analysis is conducted to clarify the reasons behind the inability to attain subambient cooling.

‘Lab around fiber’ humidity-enhanced ammonia sensor: Multimode interference functionalized by graphene oxide

In the paper, a fiber-optic ammonia sensor based on a no-core fiber (NCF)-type multimode interferometer is proposed. This sensor can utilize high humidity to enhance the sensitivity for ammonia detection. It is easily constructed by fusion splicing single-mode fiber (SMF)-NCF-SMF structure. The NCF is tapered to improve sensitivity for surrounding refractive index. To impart ammonia sensing capability to the structure, the interferometer is coated alternately with graphene oxide (GO)/ polyethyleneimine (PEI) composite films using the layer-by-layer method (LbL). The surface morphology and composition of the GO/PEI composite films are characterized using scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The ammonia sensing performance is tested, and the experimental results indicate that the central wavelength has obvious response of ammonia concentrations changing. The ammonia concentrations sensitivity in a high humidity environment is higher than low humidity environment, and the maximum sensitivity is 22.8 pm/ppm. The fiber-optic ammonia sensor designed and fabricated in this study utilizes the enhancement effect of water molecules on ammonia adsorption to improve the sensitivity of the sensor. This approach addresses the issue of poor moisture resistance in traditional ammonia sensors, thereby further expanding the application scenarios of ammonia sensors.

Charge characteristics of co-electrospun nanofiber membranes and their application in high-humidity environment

Enhancing the charge density and charge stability is an important approach to improve the filtration performance of electrospun nanofiber air filters. In the present study, the polymers with different electron transport capabilities were co-electrospun in pairs to prepare charge-enhanced nanofiber membranes. The results showed that the average surface potential of the interfacial regions of polyamide 6 (PA6) and polyvinyl chloride (PVC) nanofibers was 165 mV, which was substantially higher than the non-intersection area of nanofibers. The charges induced by the contact-induced electrification between nanofibers accumulated in the intersection area of the hybrid nanofibers, which contributed to the high surface potential of the nanofiber membranes. Moreover, the co-electrospinning of polymers allowed the positively charged PA 6 nanofibers and negatively charged PVC nanofibers to coexist in the nanofiber membranes. Benefiting from these charge characteristics, the co-electrospun PA 6/PVC nanofiber membranes exhibited an average filtration efficiency of 99.73 % for 50–500 nm particles at the face velocity of 5.3 cm/s, and the pressure drop was 130 Pa. A hydrophilic fiber layer was employed to mitigate the influence of humidity on the charge decay and pressure drop growth of thenanofiber membrane. The growth rate of pressure drop of the protected nanofiber membrane was as low as 0.95 Pa/min under the challenge of water droplets. In contrast, the growth rate of pressure drop for common membrane based filters was in the range of 5–120 Pa/min. Additionally, the color of the hydrophilic layer changed corresponding to the water content in the air filters, which could serve as an indicator for the filter service life visible to naked eyes. This study provides a new approach for charging nanofiber membranes and improving their filtration performance stability in practical applications.

Moisture‐Resistant Nanofiber Membrane Loaded with Copper‐Manganese‐Tin Oxides for Dust and CO Filtration in High Humidity Environments

AbstractThis study presents a novel protective membrane, (0.8MnCuSnOx‐NaCl)@M, designed for high‐efficiency filtration of dust particles and carbon monoxide (CO) gas offers superior moisture resistance, air permeability, and catalytic functionality in high‐humidity underground settings. The membrane, incorporating tin oxide‐doped CuMnOx into polyvinylidene fluoride (PVDF) fibers with sodium chloride (NaCl), achieves 99.99% air filtration efficiency, 323.68 mm s−1 air permeability, and 92.5% CO catalytic filtration efficiency. Concurrently, the membrane exhibited exceptional hydrophobicity, characterized by a substantial water contact angle of 116.7°, negligible water staining, and a high hydrostatic pressure rating of 2035 Pa, suitable for humid environments. Furthermore, the water absorption profile of the membrane featured a diminished hydroxyl vibrational band, accompanied by a sustained CO conversion efficiency, attesting to its resistance to moisture‐induced deterioration. Computational fluid dynamics (CFD) simulations further clarify the membrane's filtration mechanism, indicating its potential for selective CO and particle filtration. This study provides a reliable idea for the development of moisture‐resistant fiber membranes with high efficiency for filtration of dust and CO. and underscores the synergy of experimental and theoretical approaches.

Optimization of conventional-zeolite-synthesis from waste pumice for water adsorption

This research reports conventionally-synthesized-zeolites with comparatively large surface area (SSA) and water-uptake prepared solely from waste-pumice. Notably, the synthesis process avoided using additional commercial raw materials, organic templates, and high temperatures, so that the process was less costly and ecofriendly. To optimize the process, the synthesis time was varied, and the mixture of the raw material and alkaline solution was stirred for 12 h. The zeolite mother liquor was also recycled. Water adsorption experiments were carried out using gravimetric measurements. The Na-P1-rich zeolite product with an optimal water uptake of 0.256 g/g was synthesized after 48 h of hydrothermal activation (H). On the other hand, the product’s optimal SSA of 186 m2/g was achieved after 36H under similar conditions (rich in faujasite). Adsorption isotherms showed that water uptake increased with activation time and with the inclusion of mother liquor recycling. Furthermore, recycling resulted in a product with enhanced SSA compared to its precursor. Un-recycled products exhibited relatively high-water uptake both at low and high relative-pressure, while the recycled product had a high uptake at high relative pressure. All products could be used in adsorption heat pump (AHP) applications (air conditioning) suited for high relative humidity (RH) environments. However, high-synthesis-time non-recycled products could also work for low RH AHP applications.

Investigation of the competitive adsorption mechanism between typical volatile organic compounds (VOCs) and water vapor in waste gas emissions from the fermentation industry

ABSTRACT The fermentation waste gas, characterized by high humidity and diverse volatile organic compounds (VOCs), poses challenges for adsorption in activated carbon devices. In this study, starch-based activated carbon was used as an adsorbent, targeting typical VOCs from fermentation industries-methyl mercaptan, toluene, and n-hexane. The adsorption behavior of water vapor and VOCs on the carbon interface was analyzed through adsorption experiments, structure characterization, and molecular simulations. Results showed that at 70% RH, the adsorption capacities of toluene and n-hexane experienced a reduction of 42.15% and 59.24% respectively compared to their respective capacities without water vapor at the breakthrough moment, while methyl mercaptan’s capacity increased by 32.29% due to dissolution in condensed water within micropores. Water displaced all three VOCs during multicomponent adsorption. Reducing surface carboxyl groups, pyrrolic-N, and pyridinic-N enhances selective adsorption of VOCs. Among the VOCs, toluene shows the strongest interaction with activated carbon, followed by n-hexane and then methyl mercaptan. However, a water film under high humidity hinders the adsorption of n-hexane and toluene, reducing selectivity. These research findings will contribute to a comprehensive understanding of the mechanisms underlying the absorption of VOCs in high humidity environments by activated carbon.