Humid Environment Research Articles

Water Permeability and Oxygen Transport Resistance of Hydrophilic and Hydrophobic Composite Microporous Layer Coated Gas Diffusion Layer

Enhancing water management to mitigate the performance impact of humidity fluctuations is crucial in PEFC applications. A novel microporous layer (MPL) incorporated with both hydrophilic and hydrophobic properties, applied to the gas diffusion layer (GDL), has been developed and demonstrated to enhance robustness under varying humidity levels. This study utilized water permeability test results to analyze the composite MPL, distinguishing between hydrophobic and hydrophilic absolute permeability ratios. By elucidating these ratios, insights into their roles in liquid water distribution and oxygen transport resistance were gained, distinguishing the composite MPL from conventional hydrophobic and hydrophilic MPLs. Ultimately, the performance of the composite MPL under high and low humidity conditions highlighted its robustness across diverse humidity environments.

Enhancing Electrospinnability of Chitosan Membranes in Low-Humidity Environments by Sodium Chloride Addition.

The electrospinning of pure chitosan nanofibers is highly sensitive to environmental humidity, which limits their production consistency and applicability. This study investigates the addition of sodium chloride (NaCl) to chitosan solutions to enhance spinnability and mitigate the effigurefects of low humidity. NaCl was incorporated into the electrospun chitosan solution, leading to increased conductivity and decreased viscosity. These modifications improved the electrospinning process. Comparative analyses between chitosan membranes (CM) and sodium-chloride-added chitosan membranes (SCM) revealed no significant differences in chemical structure, mechanical strength, or in vitro cell proliferation. This indicates that the addition of 1% (w/v) NaCl does not adversely affect the fundamental properties of the chitosan membranes. The findings demonstrate that NaCl addition is a viable strategy for producing electrospun chitosan nanofibers in low-humidity environments, maintaining their physicochemical properties while enhancing spinnability.

Superhydrophobic nanocellulose aerogel for thermal insulation and thermal resistance up to 1300 °C

Nanoellulose aerogel (NCA) has the advantages of good flexibility, low density, and excellent thermal insulation. Its raw materials are widely sourced, renewable, and degraded, thus NCA has attracted significant interest ofresearchers in the field of insulation. However, low strength, hydrophilicity, and flammability seriously hinder its application. Here, a superhydrophobic NCA (Si-PA-PAE-NCA) with a multiscale structure is reported. Si-PA-PAE-NCA exhibits excellent compression strain (up to 8.674 MPa with strain at 80 %). A low thermal conductivity of 23.9 mWm−1 K−1 endows this aerogel with superior thermal insulation property. Compared to only the surface superhydrophobility of other NCAs, both the surface and interior water contact angles of Si-PA-PAE-NCA are up to 157°. Owing to this distinguished superhydrophobicity, Si-PA-PAE-NCA can maintain its stable thermal insulation property in a high humidity environment (90 % humidity). Importantly, Si-PA-PAE-NCA can withstand 1300 ℃ flame for 70 min, far exceeding previously reported NCAs. Besides, this aerogel exhibits the highest LOI value (45.9 %) ever recorded for NCAs thus far. Notably, there is no inorganic substance within the aerogel. Together with its scalability, sustainability, and degradability, Si-PA-PAE-NCA will have great application prospects in the insulation area.

Influence of environmental humidity during filament storage on the structural and mechanical properties of material extrusion 3D-printed poly(lactic acid) parts

Material extrusion (MEX) is one of the most widely used additive manufacturing techniques these days. This study investigates how the properties of MEX 3D-printed objects depend on the relative humidity (RH) conditions in which filaments are stored before and during the manufacturing process. Poly(lactic acid) (PLA) filament was drawn directly from a humidity-controlled chamber into the MEX 3D printer's nozzle. For each set of samples, the filaments were conditioned under different RH conditions, ranging from 10 % to 90 %. The macrostructure of the fabricated products was characterized using computed tomography, revealing increased porosity at higher RH values (from 0.84 % to 4.42 %). The increased porosity at higher storage RH is attributed to under-extrusion and volatile entrapment due to excess moisture. With growing storage RH, the melt flow rate of PLA also gradually increased, indicating a plasticizing effect of humidity on the biopolymer. Gel permeation chromatography and differential scanning calorimetry analyses were conducted to determine whether hydrolytic chain scission took place when PLA was processed in the presence of excessive moisture. Neither measurement indicated any considerable alteration in molecular integrity and crystalline structure as a function of storage RH. Mechanical tests, however, revealed a reduced load-bearing capacity of the manufactured PLA specimens. Flexural strength decreased from 103.0 to 99.6 MPa, and the impact strength dropped from 18.2 to 16.2 kJ/m2, which is ascribed to the increasing size of pores inside the specimens with increasing storage RH. These findings should be taken into account when designing and processing PLA products by MEX-based additive manufacturing.

N-doped carbon nanospheres synthesized from a newly designed eco-friendly sustainable polymer for highly selective CO2 capture.

N-doped carbon nanospheres and porous carbon were produced by a hydrothermal template and the activation of hexamethylenetetramine (HMTA as a nitrogen source and activator) and ZnCl2 (only as an activator) from a poly(Ri-S-ε-CL-PDMS) multiblock/graft copolymer produced using a renewable resource and eco-friendly autoxidation. N-doped carbon nanospheres (PPiSiHMTA) exhibited excellent CO2 adsorption (2.73mmol/g at 0°C and 0.15atm, 1.72mmol/g at 25°C and 0.15atm) and CO2/N2 selectivity (344-512). Despite the higher BET surface area and pore volume, porous carbon (PPiSi) showed low CO2 adsorption (1.21 and 0.71mmol/g, 0.15atm) and CO2/N2 selectivity (57 and 112). PPiSiHMTA and PPiSi have low isosteric heats of adsorption (Qst, 18-33kJ/mol) and stability in humid environments. In addition, PPiSiHMTA exhibited an excellent CO2 recycling performance. The experimental data on CO₂ adsorption was evaluated using various isotherm models, including Freundlich, Langmuir, Sips, and Temkin. The results demonstrated a nearly perfect fit between the Freundlich isotherm and the experimental data, indicating the heterogeneous nature of the adsorbent surfaces. Our study is promising for industrial applications, offering excellent CO2 adsorption, CO2/N2 selectivity, moisture stability, and porous material fabrication strategies.

Fabrication of core-shell structural Y@VTMS-DVB composites with enhanced hydrophobicity for toluene capture under humid environment

Zeolite Y serves as an effective adsorbent for VOCs capture due to its ordered porous structure, exceptional thermal stability, chemical resistance and fine-tune key properties. However, the hydrophilicity caused by the low SiO2/Al2O3 ratio seriously limits its industrial application, especially in humid environments. In this work, a series of core-shell composites Y@VTMS-DVBn were prepared through surface grafting and copolymerization. A variety of characterizations were utilized to study the structural and morphological changes of the prepared samples. The dynamic breakthrough adsorption experiment showed that the toluene uptake was significantly improved from 1.77 mg/g to 53.09 mg/g under 30 % relative humidity. Moreover, the core-shell composite exhibited excellent regeneration properties, the adsorption capacity remained 90 % under wet conditions after 6 cycles of regeneration. Adsorption kinetic analysis revealed that the adsorption behavior of toluene on the prepared adsorbents was primarily physical adsorption. These results show that the core-shell composite is a promising candidate for VOCs removal in industrial application.

Stretchable MWCNTs-OH/PDMS composite elastomer with hierarchical porous structure for wideband THz absorption

It is important to develop a wideband THz absorber for the prevention of terahertz electromagnetic pollution and information leakage. Some commonly used methods, such as metamaterials or dynamic modulation technology, have played important roles in the study of wideband THz absorbers. However, most of these absorbers are rigid or non-stretchable, which limits the practical applications in large mechanical deformation and non-plane scenarios. In the paper, we proposed a stretchable MWCNTs-OH/PDMS composite elastomer using the sugar template method. A series of characterization methods were carried out to verify the excellent compatibility of PDMS and MWCNTs-OH. Benefiting from its hierarchical porous structure, the draw-length ratio of sample and tensile strength reaches ∼ 190% and ∼ 0.4 MPa, respectively. More THz waves could be trapped inside the sample for conductive loss because of better impedance matching and conductivity loss (the smallest square value is ∼0.4 kΩ/□), which leads to wideband and high absorptivity (over 98% in 0.2∼2.0 THz range). Furthermore, the tested value of EMI SE was over 10 dB in 0.22∼1.82 THz frequency range at transmission mode. Combined with inherent hydrophobicity characteristics, the material also could be used in humid and rainy environments. The systemic study of stretchable MWCNTs-OH/PDMS composite elastomer will provide theoretical and technical support for subsequent THz absorption in practical scenarios.

Innovative risk management techniques in food safety: A review of best practices and emerging trends

Effective risk management in food safety is critical to ensuring consumer protection and maintaining the integrity of global food supply chains. Traditional approaches, such as Hazard Analysis and Critical Control Points (HACCP) and Good Manufacturing Practices (GMP), have long been the foundation of food safety risk management. However, with the increasing complexity of food production and distribution, new challenges demand more advanced techniques. This review explores innovative risk management methods, focusing on best practices and emerging trends that are transforming food safety. Technological advancements are driving much of this innovation. Predictive analytics and machine learning now allow for real-time monitoring and hazard detection, improving the accuracy of risk assessments. Blockchain technology is being leveraged for enhanced traceability and transparency in the supply chain, ensuring faster recall management and improved accountability. The integration of IoT (Internet of Things) sensors provides continuous monitoring of environmental factors like temperature and humidity, which are critical in preventing contamination, especially in perishable goods. Additionally, risk-based inspection systems, supported by regulatory frameworks such as the Food Safety Modernization Act (FSMA), are becoming more prevalent, prioritizing resources where risks are highest. Emerging trends such as artificial intelligence (AI) for predictive risk management, big data analytics, and sustainability-driven risk approaches are reshaping the landscape. These innovations not only enhance risk mitigation but also align with consumer demands for greater transparency and environmental responsibility. Despite challenges such as cost, data privacy, and regulatory hurdles, the future of food safety lies in the continued development and adoption of these advanced techniques. This review highlights the potential of these innovative practices to improve food safety standards and protect public health in an increasingly interconnected world. Keywords: Innovative, Risk Management, Food Safety, Review.

Qualitative and quantitative detection of camellia oil adulteration using electronic nose based on wavelet decomposition humidity correction

This study addresses the challenge of environmental humidity impacting the accuracy of metal oxide semiconductor (MOS)-based electronic nose systems in detecting adulterated camellia oil. A self-developed electronic nose platform with eight MOS sensors was used to detect adulteration in camellia oil mixed with varying ratios of rapeseed, soybean, and corn oils at different humidity levels (20%, 40%, and 60%). Wavelet decomposition using fourth-order Symlet wavelet was applied to correct response signals, mitigating humidity's effect on detection accuracy. Linear discriminant analysis (LDA), support vector machine (SVM), and random forest (RF) were employed to build qualitative identification models using pre- and post-correction datasets, while partial least squares regression (PLSR) and backpropagation neural network (BPNN) were used for quantitative prediction. Results showed that both qualitative and quantitative models significantly improved performance after correcting signal drift with wavelet decomposition. The qualitative model's 10-fold cross-validation prediction accuracy increased to 98.67% from 88.67%, while the quantitative model's average R2 reached 0.99 with RMSE reduced to 3.64 mL/100 mL, compared to pre-correction R2 of 0.86 and RMSE of 9.63 mL/100 mL. Notably, the RF and BPNN models outperformed others in qualitative and quantitative detection, respectively. These findings highlight the potential of electronic nose technology with humidity correction for authenticating camellia oil.

Rapid and Facile Synthesis of Homoporous Colorimetric Films Using Leaf Vein-Mediated Emulsion Evaporation Method for Visual Monitoring of Food Freshness.

A new method for rapid and facile fabrication of homoporous films with high volatile amine sensitivity was developed. First, red cabbage anthocyanin was encapsulated in ethyl cellulose to form water-in-organic (W/O) emulsion. Afterward, the W/O emulsion was rapidly dried using the supporting matrix Magnolia Grandiflora Linn leaf vein at 60% relative humidity and 50 °C to form a colorimetric film with regular hexagonal pores with an average side length of about 23 μm. The films exhibited good sensitivity to ammonia (NH3), dimethylamine, and trimethylamine, with limit of detection of 0.26, 0.24, and 0.38 μM, respectively, and high stability when stored in high humid environments. An obvious color change of the films from pink to green was clearly observed during the freshness monitoring of pork, chicken, salmon, and shrimp. Thus, this work offered a novel and reliable method for the development of porous films for food freshness monitoring.

NUMERICAL MODELLING OF RADIATOR SYSTEM PERFORMANCE UNDER BAUCHI CLIMATIC CONDITIONS

The cooling system of the car plays a crucial role in managing the excess heat generated by the engine during its operation. Among its components, the radiator is pivotal for efficiently dissipating heat. However, the effectiveness of a radiator is influenced by various factors, including external conditions such as atmospheric temperature, humidity, and wind speed. This research aimed to understand the impact of Bauchi climatic conditions on automotive radiators. A comprehensive approach was employed, utilizing reverse engineering techniques to create a detailed model of a car radiator using SolidWorks, a computer-aided design (CAD) software. This model underwent simulations using ANSYS software with water as the coolant fluid. Environmental temperature, humidity, and wind speed data for Bauchi North and Bauchi South were sourced from the Nigerian Meteorological Agency (NiMet). The simulation timeframe spanned from January to December. The study shows the effects of environmental temperature, humidity, and wind speed on radiator performance. The highest outlet temperature recorded was 43.50°C at a flow rate of 2500 kg/h in April, and the lowest outlet temperature was 40.01°C at a flow rate of 500 kg/h in Bauchi North. For Bauchi South, the highest outlet temperature was 40.98°C at a flow rate of 2500 kg/h in April, and the lowest was 37.12°C at a flow rate of 500 kg/h. This study highlights the pivotal role of Bauchi's atmospheric conditions in influencing radiator performance, emphasizing the interplay between environmental factors and engineering design in automotive cooling systems.

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.