Humid Environment Research Articles

Arc-shaped air layer bioinspired by ginkgo nut to resist high humidity environment for PET fabrics

Developing simple processes and significant effect modification method for polyester (PET) fabrics to resist hygrothermal aging is a formidable challenge. In this study, inspired by the silver mirror phenomenon of natural ginkgo nut, we utilized the pea pod-shaped nanoparticles that zinc oxide (ZnO) was encapsulated in polyhedral oligomeric silsesquioxane (ZnO@POSS), and polydimethylsiloxane (PDMS) to construct stabilized arc-shaped air layer on the PET fabric surface to resist high humidity environment. The round belly structures of pea pod-shaped ZnO@POSS and interlaced physical networks assisted by PDMS on the PET fabrics surface served as the crucial roles to capture and retain air, resulting in the capacity of the arc-shaped air layer was significantly larger than other microstructures underwater. The water vapor was prevented from entering the fabric interstices that the self-catalytic hydrolysis behavior of PET macromolecular chains was efficiently restrained, and the strength retention of PET fabric was significantly improved from 45 % to 89 % after accelerated hygrothermal aging test (60 °C, 80 % RH, 600 h). This work represents a simple and effective approach to improve the durability for PET fabrics in high humidity environments.

Sulfate resistance of mortars under semi-immersion condition: Impact of environmental humidity and fly ash content

Fly ash can effectively improve the sulfate resistance of immersed concrete by refining the pore size. However, increase of capillary pores may not be a good thing for salt crystals. In this paper, the effects of fly ash contents and environmental humidity on the sulfate resistance of semi-immersed mortars was investigated by appearance, mechnical strength, and microstructure. Capillary adsorption capacity, ingressed sulfate concentration and erosion productes were further investigated to analyze damage mechanism of mortar under semi-immersion condition. Lower environmental humidity and higher fly ash content were not conducive to the sulfate resistance of semi-submerged mortar, when the humidity was lower than 55 %, the fly ash content should be further reduced. The migration of sulfate ions in capillary pores and the physical salt crystallization in the region of humidity change are the main reasons for the damage.

Ice vests extend physiological work time while wearing explosive ordnance disposal protective clothing in hot and humid conditions

BackgroundExplosive ordnance disposal (EOD) technicians may be required to work in hot, humid environments while wearing heavy protective clothing. We investigated the ability of an ice vest to attenuate physiological strain and subsequently extend work tolerance. MethodsEight male participants (24.3 ± 4.1 yr, 51.9 ± 4.6 mL kg−1 min−1) walked (4.5 km h−1) in simulated hot and humid conditions (35 °C; 50% relative humidity). Participants wore either an EOD suit (CON) or EOD and ice vest (IV). Heart rate, core and skin temperature were recorded continuously. ResultsParticipants walked longer in IV compared to CON (8.1 ± 7.4 min, p < .05). Over 90% of trials were terminated based on participants reaching 90% of their maximum heart rate. IV resulted in cooled skin (p < .001) and a physiologically negligible change in core temperature (p < .001). A condition by time interaction was identified for heart rate (p < .001), with a lower rate of rise in the IV condition. ConclusionsThe cardiovascular inefficiency that limited performance was attenuated in the IV condition. The ice vest facilitated heat loss from the periphery; thus, the observed reduction in heart rate may reflect the preservation of central blood volume. The results identify the efficiency of a simple, inexpensive ice vest to assist EOD technicians working in the heat.

The mechanical properties of concrete exposed to harsh and complex environments of plateaus at early ages

The independently designed walk-in concrete low-pressure forming chamber and complex environment simulation chamber were employed to more accurately investigate the evolution of mechanical properties of concrete under the complex environment of the plateau. The quantitative comparison of the differences in the impact of each environmental factor on performance under complex coupled environments was conducted using two methods: grey correlation analysis and relative strength method. Meanwhile, the hydration and pore structure of concrete under the complex environment of plateau were studied by TG analysis and MIP analysis. The results showed that the high-altitude complex environment has a significant deterioration effect on the mechanical properties of concrete, mainly due to the decrease in the degree of hydration and pore structure deterioration. The environmental humidity and temperature difference are the main factors affecting the mechanical properties, and the complex environment has a more significant effect on the flexural strength of concrete than the compressive strength of concrete.

Revealing the promotional effect of Zr and phosphate Co-decorated on δ-MnO2 catalysts for highly efficient catalytic elimination of chlorinated VOCs: An experimental and theoretical study

The development of advanced catalysts for catalytic oxidation of CVOCs still presents challenges in terms of low activity, chlorination poisoning and the formation of toxic byproducts. In this study, a series of nP-MnxZry catalysts with exceptional catalytic oxidation activity were developed for the removal of CVOCs in industry. Among them, 15P‐MZ exhibited the optimal catalytic activity and stability for CB degradation, achieving a T90 of 180 ℃. Notably, the CB oxidation rate of 15P‐MZ was found to be 5.76 times higher than that of MnO2 at 155 °C. Structure and properties analysis combining with DFT calculations revealed that the dual modification strategy involved Zr doping and phosphate loading induced the formation of high concentration of oxygen vacancy over 15P‐MZ, which enhanced oxygen mobility, facilitating the breakage of the aromatic ring. Meanwhile, this strategy introduced more Brønsted acid sites, promoting the dissociation of Cl in the form of HCl, thereby inhibiting the formation of polychlorinated byproducts. Moreover, the activation effect of phosphate on the dissociation of H2O further promoted the Cl dissociation, thereby regenerating more active sites and improving catalytic activity and stability in humid environment, making it more promising for industrial applications.

A new epifoliar melioloid fungus from the Siwalik (Miocene) of Himachal sub-Himalaya and its palaeoecological implications

A new fossil epifoliar ascomycete (Ascomycota), Meliolinites miocenicus nov. sp. (fossil Meliolaceae), occurs in situ on a compressed monocot leaf from middle Siwalik (Late Miocene, ca. 12–8 Ma) sediments of Himachal Pradesh, Western Himalaya. The fossil consists of a well-preserved mycelium of superficial, brown to dark brown, septate, thick-walled, branched hyphodiate hyphae; a sub-globose, dark brown putative ascoma, and an oblong to broadly cylindrical, five-celled, four-septate, mature germinating ascospore. The new fossil differs from earlier reported melioloid fossils primarily in the morphology of appressoria. Meliolinites miocenicus nov. sp. on its host is evidence of the existence of a biotrophic relationship at the time of deposition. Qualitative climate data using plant megafossils recovered from the same fossil locality indicate that M. miocenicus nov. sp. and its host thrived in a warm and humid tropical environment.

High-performance flexible humidity sensor based on B-TiO2/ SnS2 nanoflowers for non-contact sensing and respiration detection

The development of flexible humidity sensors is essential for the advancement of wearable devices and electronic skin. However, the process of preparing these sensors is typically complex, and they often suffer from poor stability and a limited sensing range, which fails to meet the requirements for practical applications. Here, we prepared SnS2 with nanoflower morphology by hydrothermal method, and successfully prepared a high-performance flexible humidity sensor with a high response range (20-95 %) by compositing it with B-TiO2 nanoparticles with oxygen defects after sodium borohydride reduction and coating it on a PET flexible substrate. This sensor demonstrates an exceptional response (753.2 at 90 % RH) in high humidity environments and exhibits rapid response (13 s) and recovery times (19 s). Moreover, the sensor accurately detects human breathing patterns and frequencies, making it suitable for non-contact sensing applications. This research offers valuable insights into the simplified preparation and advancement of flexible humidity sensors.

Study on the preservation effect of 60Co-γ ray irradiation on potatoes

To evaluate the effect of irradiation on the preservation of potatoes, fresh potatoes were selected as the irradiation objects, and irradiated with 60Co-γ radiation source for 0, 100, 200, 500 and 1000 Gy, respectively. During the irradiation, the well-packaged Y1.79Bi0.01Eu0.2MgTiO6 novel thermoluminescence dosimeter material was placed together with the potatoes at the same position. Then, the potatoes were stored in the same temperature and humidity environment, and the quality changes of the potatoes were observed. The Y1.79Bi0.01Eu0.2MgTiO6 material had good performance indicators, and was used to measure the irradiation dose of the potatoes. The experiment showed that irradiation could appropriately extend the storage time of potatoes, and gamma irradiation of about 1000 Gy could achieve the best preservation effect. The main pathogenic fungi that cause dry rot of potatoes were Fusarium solani and Fusarium oxysporum, and the appropriate dose of 60Co-γ irradiation could effectively inhibit the spread and growth of these fungi.

A 3D printed serrated contact structure triboelectric nanogenerator for swimming training safety monitoring

The wearable electronic devices integrated with 3D printing have attracted much attention, but the continuous power supply demand and limited application scenarios have limited their development. Here, we propose a 3D printed serrated contact structure triboelectric nanogenerator (S-TENG) designed for mechanical energy harvesting and swimming training safety monitoring. Leveraging the advancements in 3D printing technology, we created a flexible, lightweight sensor integrated with polytetrafluoroethylene (PTFE) and polyethylene terephthalate (PET) films on a serrated substrate. This configuration enhances the contact surface area, leading to a significant improvement in energy harvesting efficiency compared to flat structures. Specifically, the serrated structure resulted in a 64 %, 63 %, and 47 % increase in open-circuit voltage (Voc), short-circuit current (Isc), and transferred charge (Qsc), respectively, owing to the contact area and unique surface functional structure. The S-TENG device exhibits excellent performance under various bending angles, with Voc, Isc, and Qsc reaching up to 98.04 V, 4.35 μA, and 38.51 nC at 90° bending. Additionally, the S-TENG maintains stable output in different humidity environments due to its fully encapsulated design, ensuring reliable operation in aquatic settings. The S-TENG can accurately measure elbow swing amplitude and frequency, providing valuable real-time data for athletes and coaches. The S-TENG's ability to detect irregular movements and potential drowning incidents underscores its promise in enhancing swimmer safety. This research demonstrates the S-TENG's utility in both energy harvesting and motion monitoring, paving the way for advanced wearable sports sensors in various athletic disciplines.

Optimizing Aerofoil Design: A Comprehensive Analysis of Aerodynamic Efficiency through CFD Simulations and Wind Tunnel Experiments

This study explores the aerodynamic properties of different aerofoil shapes and their performance under varying flow conditions to identify the most efficient design based on lift-to-drag ratio, stall behaviour, and overall aerodynamic efficiency. Using Computational Fluid Dynamics (CFD) simulations, several aerofoil profiles were analysed at different angles of attack and flow speeds. These simulations were validated through wind tunnel experiments, offering a comprehensive understanding of aerofoil performance in real-world scenarios. The combination of CFD analysis and wind tunnel testing enabled a thorough assessment of each aerofoil shape, leading to the discovery of a specific aerofoil with a high lift-to-drag ratio and stable performance at high angles of attack. These results have significant implications for the design of wings and blades in aerospace and aeronautical applications, improving fuel efficiency and performance in both aviation and wind energy sectors. Additionally, dynamic roughness shows potential in reducing separation bubbles, but further investigation is needed to assess its effectiveness at higher angles of attack and elevated Reynolds numbers. Understanding the scalability and practical application of dynamic roughness in real-world scenarios is essential. Current research on surface modifications like dimples and riblets lacks optimized configurations for varying conditions. More research is needed to understand the interaction between surface geometries and the boundary layer, particularly at higher angles of attack and Reynolds numbers. Combining experimental and numerical methods can provide a comprehensive understanding of flow control techniques. The limited research on applying flow control strategies to wind turbine blades indicates a significant opportunity to improve wind energy efficiency. Future studies should focus on optimizing multiple techniques and addressing practical challenges, such as durability, cost-effectiveness, and integration into existing systems. Investigating the cost-effectiveness and durability of these modifications for long-term use will be vital for their successful adoption in the industry. Expanding research to include the effects of environmental factors like temperature and humidity will offer a more complete understanding of flow control in various operating conditions. By addressing these gaps, advancements in aerodynamic performance can be achieved, benefiting the aerospace and wind energy sectors.

Molecular simulation on competitive adsorption of ethanol, acetaldehyde and acetic acid on zeolites in humid conditions

Adsorption is a key technique for purifying volatile organic compounds (VOCs) from indoor air. Due to the complexity of multi-component VOCs and humid environment, the competitive adsorption among VOCs under the influence of water vapor remains unclear, which limits adsorbent selection and performance prediction. In this work, adsorption characteristics of typical indoor VOCs (ethanol, acetaldehyde, and acetic acid) on commercial zeolites (BETA-25 and ZSM5-300) under varying humidity were studied through molecular simulation. The simulation based on charge-corrected molecular structures and force field was validated by experiments. The unary, binary and ternary adsorption isotherms of three VOCs were obtained. At both dry and wet conditions, the VOCs with higher polarity shows greater adsorption capacity: acetic acid > ethanol > acetaldehyde. BETA-25 exhibits stronger adsorption on all three gases under dry conditions, while under wet conditions ZSM5-300 shows greater adsorption capacity of ethanol and acetaldehyde with lower polarity as compared to BETA-25. Simulation of adsorption energy and adsorbate density distribution in ternary equilibrium demonstrates the presence of water vapor alters the sorbate-sorbent interaction, particularly for ethanol and acetaldehyde showing stronger adsorption on BETA-25 than on ZSM5-300 at dry conditions but reversely at wet conditions. The lower-silica zeolite favors the adsorption of highly-polar VOC regardless of water, and the higher-silica counterpart with greater hydrophobicity facilitates adsorption of less-polar compounds in competing with water. The findings in this work can provide methodological reference for adsorbent screening and data basis for real VOCs purification applications.

Enhanced oxygen barrier properties of sodium alginate coatings in humid environments: ionic crosslinking of sodium alginate by calcium ions released from calcium hydrogen phosphate and calcium carbonate

Enhanced oxygen barrier properties of sodium alginate coatings in humid environments: ionic crosslinking of sodium alginate by calcium ions released from calcium hydrogen phosphate and calcium carbonate

Influence of fungicide on soybean seed quality from delayed harvest and environment

AbstractField studies in 2019–2020 evaluated the influence of fungicide application on seed quality from delayed harvest (approx. 20, 30, and 44 days after optimum harvest timing, i.e., 13% seed moisture). Treatments included nofungicide, pydiflumetofen plus difenoconazole (13.7 fl oz/acre Miravis Top, Syngenta), or mefentrifluconazole plus pyraclostrobin plus fluxapyroxad (8 fl oz/acre Revytek, BASF). Effect of environment was investigated in both field (natural rainfall events) and environmentally controlled growth chambers (79°F or 90°F with 30% or 100% relative humidity and exposed for 48 or 96 h) for potential impacts on soybean [Glycine max (L.) Merr.] seed quality. Seed quality was based on a rating scale of 1 to 10 with 1 being seeds in good condition and 10 being seeds in poor condition, based on USDA reference images. Fungicide application had no effect on seed quality from delayed harvest or a saturated environment (100% relative humidity). Delaying harvest beyond approximately 20 days past optimum timing can result in reduced seed quality regardless of fungicide application (1.0 to 2.0 vs 4.0 to 8.1 rating). In addition, seedpod exposure averaged across temperature and relative humidity environments for as little as 96 h after optimum harvest timing can result in deteriorating seed quality issues (3.2 vs 1.4 rating) regardless of fungicide application. Results indicate that soybean harvest delayed 20 days after optimum timing and subjected to seasonal rainfall events or seedpods exposed to completely saturated conditions for 96 h associated with a tropical weather event will result in soybean seed quality deterioration regardless of fungicide application.

Rapid ambient pressure drying preparation of bulk ZrO2-SiO2 aerogels with high thermal stability

In this study, the sol-gel stage co-precursor method was used to hydrophobically modify the gel and increase the content of alkali catalyst in the gel, thereby reducing the capillary force generated during ambient pressure drying and enhancing the strength of the gel skeleton. This improvement makes the gel skeleton structure not easy to destroy during the rapid drying process, thus greatly reducing the preparation time of atmospheric pressure drying, which could be as short as 10 h. It is worth mentioning that this method does not require extensive use of modifiers and organic solvents, so it has low cost, high efficiency, and broad industrial production application prospects. The experimental results show that the DDS/ZSA aerogel exhibits the lowest thermal conductivity (0.035 W m−1 K−1) when the dilute ammonia content is 5 ml. However, it should be noted that too low or too high an amount of dilute ammonia will lead to a decrease in aerogel performance, so it needs to be controlled within the appropriate range. In addition, the prepared aerogel has excellent hydrophobic properties with a contact angle greater than 140° and excellent thermal stability at 1000 °C, which can be used in harsh, humid, and high-temperature environments.

Vitamin E Supplementation to Quail (Coturnix-coturnix Japonica) Treated by Heat Stress: Effects on Blood Hematology Parameters

Heat stress is a major problem in poultry farming. Environmental temperature and humidity greatly in fluence the performance of poultry, especially quails raised in tropical environments. Vitamin E is a fat-soluble vitamin that has an antioxidant effect. This study aimed to evaluate the effect of vitamin E supplementation on the blood profile of quails kept under heat stress. This study used 4 treatments of T0 as Control (Commercial Feed + Heat Stress 35 oC); T1 (Control + 100 mg of vitamin E/kg); T2 (Control + 150 mg of vitamin E/kg) and T3 (Control + 200 mg of vitamin E/kg). Observed parameters of leukocytes, heterophylls, lymphocytes and monocytes. The data was analyzed by Analysis of Variant (ANOVA) if there were differences between treatments, followed by the Duncan test. The observation results showed that the addition of vitamin E could increase the number of leukocytes, lymphocytes, monocytes and reduce the number of heterophytes and the H/L ratio of quail blood that experienced heat stroke. Based on the blood profile, the addition of vitamin E as much as 200 mg/kg in feed is able to reduce heat stress due to heat stress in laying quails.

High-speed and Sub-ppm Detectable Tellurene NO2 Chemiresistive Room-Temperature Sensor under Humidity Environments

High-speed and Sub-ppm Detectable Tellurene NO2 Chemiresistive Room-Temperature Sensor under Humidity Environments

A porous IPN-structured polyurethane/epoxy grouting material with low viscosity, high strength and low volume shrinkage

Epoxy based grouting materials should concern with low viscosity, high strength, rapid curing, and low shrinkage. A polyurethane/epoxy grouting material was prepared. Through formula design, its initial viscosity was reduced to below 200 mPa·s. The morphology observation confirmed its porous and IPN structure. Compared with pure EP, its tensile strength, compressive strength, and impact strength were increased by 87 %, 20 %, and 50 %, respectively, as well as the volume shrinkage was significantly reduced. The inherent strength of PU/epoxy resin grouting materials was significantly higher than that of concrete, even in humid environments, their bond strength was 3.26 MPa. The theoretical grout flow rate and diffusion radius at different stages of the grouting process were also determined, which achieved an excellent on-site grouting effect.

Room temperature self-healing and high gas barrier properties of elastomer composites incorporated with liquid metal

Flexible electronic devices require stretchable packaging materials that provide a hermetic seal. However, conventional soft materials often exhibit strong gas permeability, making it difficult to achieve stable operation, which requires films with high deformability, self-healing capability, and gas barrier functionality. In this study, a layer by layer (LBL) method was employed to uniformly coat a controllable thickness of liquid metal (LM) onto a designed and synthesized self-healing thermoplastic polyurethane (TPU) film, successfully developing a stretchable gas barrier film (TPU/LM) with high gas barrier properties. The designed polyurethane film significantly enhanced the adhesion of the liquid metal, effectively preventing leakage. The experimental results show that the water vapor transmission rate (WVTR) of the TPU/LM composite film with a thickness of 40 μm is 4.04g/(m2·day). Compared to the film without LM, the gas barrier performance has been improved by approximately 16 times. Additionally, there is a significant enhancement in nitrogen (N2) barrier, with a permeation rate reaching 4.0*10−17 cm3 cm/(cm2·s·Pa), effectively blocking the N2 permeation. This demonstrates the universality of the TPU/LM in gas barrier applications. Furthermore, the TPU/LM film also demonstrated excellent electromagnetic shielding effectiveness. The self-healing capability of the stretchable gas barrier film allows it to recover its initial gas barrier performance after mechanical damage. Humidity-sensitive resistors encapsulated with TPU/LM exhibited stable operation in both air and 90 % humidity environments, confirming the superior barrier properties of the TPU/LM. Generally, the developed TPU/LM is suitable for packaging applications in the next generation of flexible electronic devices.

Asymmetric and mechanically enhanced MOF derived magnetic carbon-MXene/cellulose nanofiber films for electromagnetic interference shielding and electrothermal/photothermal conversion

The prosperity of wearable and microelectronic devices tremendously facilitates to exploit thin and flexible composite films with multifunction. Free-standing MXene films have aroused considerable interest in the fields of electromagnetic interference (EMI) shielding and thermal management because of brilliant electrical conductivity, distinctive layered architecture and remarkable localized surface plasmon resonance effect. Nevertheless, the inferior mechanical strength and potential performance degradation in humid environments seriously constrain their practical applications. In this regard, robust and multifunctional CoNi-MOF-74 derived magnetic carbon/cellulose nanofibers (CNF)-MXene/CNF composite films with Janus architecture were successfully constructed via two-step vacuum-assisted filtration technology. The rational arrangement of functional fillers effectively improves the impedance matching, promoting the incident electromagnetic waves to enter the films for consumption. Constructing double-layered structure could induce the generation of “absorption-reflection-reabsorption” dissipation manner, dramatically enhancing EMI shielding performance. The bi-layered magnetic carbon/CNF-MXene/CNF composite membranes (0.1 mm in thickness) realize a fascinating EMI shielding effectiveness of 68.86 dB and a superior absorption efficiency of 58.82 dB. Meanwhile, the brilliant conductivity and significant localized surface plasmon resonance effect of MXene/CNF layer endow the composite films with excellent electrothermal/photothermal conversion capability, greatly broadening application prospects. The steady temperature of the composite films is as high as 112.9 °C within 10 s under the low driven voltage of 3.0 V and the saturation temperature reaches up to 154.2 °C within 15 s at the light intensity of 1500 W/m2, respectively. Moreover, the plentiful hydrogen bonding interaction and compact interfacial combination jointly enable the composite films to possess robust mechanical flexibility, satisfying the demands in practice. This work supplies a prospective guidance for preparing flexible and multifunctional composite films with Janus architecture, revealing great application potential in wearable and microelectronic devices even under harsh conditions.

Nutrition Temperature and TDS Control System with Fuzzy Logic on Pak Choy Hydroponics (Brassica rapa subsp. chinensis)

Hydroponics is a method of cultivation that does not use soil as a medium, allowing it to be applied in limited spaces such as urban households. One of the vegetable plants that can be grown using hydroponics is pak choy (Brassica rapa subsp. chinensis). To produce healthy pak choy plants that can efficiently absorb nutrients in a hydroponic system, several factors need to be considered, such as the level of Total Dissolved Solids (TDS) in the nutrient solution, nutrient solution temperature, and air humidity in the hydroponic environment. The ideal nutrient solution temperature for hydroponic plants falls within the range of 25-27°C. In this system, a monitoring and control system will be designed to optimize the growth of pak choy plants in a Deep Flow Technique (DFT) hydroponic system. In this system, the nutrient solution temperature will be controlled with a set point of 25°C using an on/off control for a peltier device. To maintain the TDS level at a set point of 1200 ppm in the nutrient solution, fuzzy logic control will be employed, generating timer-based control signals for the nutrient pump A, nutrient pump B, and water pump. The monitoring system will be displayed on an Internet of Things (IoT) dashboard platform, such as ThingSpeak.