Moisture Resistance Research Articles

Heat flow topology-driven thermo-mass decoupling strategy: Cross-scale regularization modeling and optimization analysis

The liquid desiccant dehumidification (LDD) is both eco-friendly and highly effective in humidity control, widely investigated across diverse angles. This study expands the application of the newly devised heat current method to examine the liquid desiccant dehumidification process. It introduces a new regularized temperature, which includes using a heat flow topology driven thermo-mass decoupling strategy, and constructing the heat current model by defining both the thermal resistance and moisture resistance. It significantly extends the application of the heat current method, clarifying the thermo-mass coupling energy transfer mechanism. The findings indicate that key factors influencing system performance indicators include total thermal conductivity (αA), solution mass flow rate (ms), air-solution mass flow rate ratio (RA/S,D), and heat source temperature (tH). Furthermore, under the influence of distinct thermal conductivities, the optimal output values for performance indicators, including moisture removal rate, exergy efficiency and entransy efficiency, are determined as 8.4 g/s, 71.2%, and 12.3%, respectively. The results of synergistic influence analysis reveal that, for the performance indicator entransy efficiency, msand RA/S,D display a significant degree of synergistic influence, resulting in a strong positive effect and benefiting 68.53% of the total area. Multi-objective optimization indicates a trade-off relationship among the system performance evaluation indicators moisture removal rate, exergy efficiency and entransy efficiency, with optimal solution values of 3.25 g/s, 65.92%, and 12.01%, respectively.

Combustion and mechanical properties of pellets from biomass and industrial waste

Experimental research findings are reported on the impact of industrial waste additives on the mechanical properties of pellets, their ignition and combustion. The compositions under study consisted of wood sawdust with coal slime/peat/a mixture of straw and rice husk. Composite pellets exhibited high moisture resistance and durability when subjected to vibration. The respective coefficients were 6–32 % higher than for sawdust without additives. The ignition characteristics of wood pellets tended to worsen when additional components were used in their composition. The ignition delay times increased by a factor of 3–4. In most cases, the use of additives increased the combustion duration of pellet fuels. The greatest environmental benefits in terms of carbon oxides were gained from mixtures of straw with rice husk and coal slime. СО2 and СО emissions decreased by 10–20 % and 10–54 %, respectively. A high nitrogen content in peat, coal slime and straw led to 5–94 % higher emissions of NOx for composite pellets. Using plant biomass and peat reduced the concentrations of sulfur oxides almost 3-fold. The results of multi-criteria analysis covering 13 energy, operational, economic and environmental components suggest that the difference in the relative efficiency indicator of wood pellets and compositions with industrial waste additives is 4.4–6.5 %.

Effect of humidification on antimony-based flexible phase change memory

Ambient humidity has an important impact on the performance of flexible electronic devices, and wearable electronic devices will inevitably involve a high humidity environment. To investigate the impact of humidification on flexible phase-change memory, we prepared Sb phase-change film and memory device unit with polyether ether ketone as substrate, and studied the effect of humidification on the properties of the film and device. The results show that the effective transition from an amorphous to a crystalline state can still be achieved by the film after soaking in water for 55minutes, and the phase transition temperature increases with the increase of soaking time. Water molecules refine the film grains, resulting in increased crystalline resistance. Sb is a hydrophilic material, and its hydrophilicity decreases after crystallization. The reversible conversion of SET-RESET can be realized under different pulse widths even after the phase change memory device is soaked in water and bent many times. This study shows that antimony-based flexible phase change memory has certain deformation self-healing ability and moisture resistance, which provides a way to expand its application environment.

A Review and Thermal Conductivity Experimental Program of Mattress Waste Material as Insulation in Building and Construction Systems

The building and construction industry consumes a significant amount of natural resources alongside contributing to the generation of waste materials. Addressing the dual challenge of waste management and recycling in this sector is imperative. This study begins with a bibliometric assessment to identify waste materials used as insulation in building and construction systems. The assessment of 2627 publications revealed mattress waste materials were seldom considered. The aim of this research focuses on exploring alternative methods for repurposing mattress materials in construction, aiming to mitigate waste generation. While various materials are being recycled for building applications, this research emphasises the potential of incorporating recycled polyurethane foam (PUF) from mattresses as insulation products. A transient plane source (TPS) was employed to determine the thermal conductivity of waste mattress PUF obtained from a recycling plant in Victoria, Australia. The results exhibited promising thermal resistance, with a mean value of 0.053 Wm/K. However, optimal thermal performance was observed with increased thickness, suggesting that a thickness of 215mm aligns with industry standards for building fabric systems. Further research is required to comprehensively analyse moisture resistance and fire retardation of waste mattress materials. This paper presents key findings of current trends, limitations, and future research directions to the use of waste mattress PUF as an insulation material.

Perfluorooctanoic acid interface modification enabling efficient true-blue perovskite light-emitting diodes and air-processing compatibility

The pure-bromide quasi-2D perovskite has shown advantages in fabrication of blue perovskite light-emitting diodes (PeLEDs) due to its relatively good color stability and capability of moisture resistance. However, the performances of efficiency and luminance of pure-bromide quasi-2D PeLEDs with true-blue (470 nm−480 nm) emission are still inferior. Here, we show a interfacial modification strategy of involving perfluorooctanoic acid (PFOA) to a hole transport layer of poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS), to improve the performances of the true-blue PeLEDs. The PFOA regulates the molecular conformation of PEDOT:PSS, forming ordered PEDOT domains that improves the carrier transport and a more favorable band alignment with the perovskite emissive layers. The achieved true-blue PeLEDs show peak EQE of 6.86 % and maximum luminance of 854.10 cd/m2 at wavelength of 478 nm, which are the record values for the pure-bromide quasi-2D PeLEDs in true-blue region. Moreover, owing to the hydrophobic fluorine-carbon (C-F) chains of PFOA, we successfully fabricate the blue PeLEDs in air condition without inert gas protection. This work paves the way for commercial applications in next-generation display technologies.

Three-dimensional simulation of heat and moisture transfer in woven fabric structures

Fabric structure parameters have a significant impact on the comfort of heat and moisture transfer in garments. Previous numerical simulations required extensive mathematical calculations and mostly investigated one- or two-dimensional models of fiber assembly without considering the weave structure, which is a key parameter, that significantly influences the porosity of the woven structure and consequently its heat and moisture management. While the finite element method supports the simulation of the optimal shape and material properties with better visibility, previous finite element models focused on heat transfer and neglected water vapor transfer in fabrics. In this article, the finite element simulation of heat and moisture transfer in woven fabrics is established based on the testing principle of thermal resistance and moisture resistance tester using COMSOL Multiphysics software. In this simulation, three-dimensional parametric geometrical models of the fabric are created using curve interpolation methods by acquiring the control point coordinates of different weaves (plain, 2/2 balanced twill, and 4/1 unbalanced twill weaves). Heat and moisture transfer properties of fabric models in the horizontal and vertical directions were analyzed, including the heat flux, moisture resistance, water vapor permeability, and water vapor concentration. The article also deals with the effects of weave structure and fabric cover in a range of 72.1–85.1% on the fabric heat flux and water vapor concentration. Comparison between model and experimental results revealed that the three-dimensional simulation can accurately predict the impact of weave pattern and fabric cover on the fabric heat and moisture transfer performance. In addition, this model can be utilized to study the distribution of heat and water vapor within fabrics, providing a theoretical foundation for optimizing heat and moisture comfort in woven fabrics.

Study on Manufacturing of Bricks by Using Waste Foundry Sand

The main objective of this project is to utilize waste foundry sand (WFS) from foundry industry in manufacturing of bricks. The entire process of combining clay mixtures, forming of bricks, drying and firing was done with local conditions. With minimum process it was possible to introduce up to 30% WFS in clay bodies to produce bricks of desirable properties. The minimum average wet compression resistance of 5.54Mpa, and maximum average water absorption of 20.76% was obtained for bricks containing 30% WFS, when fired at 900 C. There was insignificant difference in apparent porosity, water absorption, and specific gravity of bricks containing WFS, when compared to commercial bricks. The addition of WFS reduced the bulk density of the bricks, which has also caused reduction in compressive strength. WFS bricks can be classified as class II bricks, based on recommendations of IS 1077 standard specification. These bricks can be used in single storied load bearing structures, and also in the construction of infill walls in multi-storied framed structures.

Nickle ion surface engineered MOF derived α-Fe2O3 octahedrons for high efficiency toluene detection with high moisture resistance and long-term stability

Metal-organic framework derivatives have become very promising candidates for gas sensors due to their advantages of large specific surface area, many surface active sites, and tunable properties. Meanwhile, Ni ion doping is an effective technique to enhance the moisture resistance of sensing materials. Inspired by this, in this work, we have successfully synthesized porous octahedral structures of Ni-Fe2O3 derived from metal-organic frameworks by in situ doping, in which the Ni contents were 0.4, 0.5 and 0.6 mol%, respectively. Notably, Ni doping changes the conductive type of Fe2O3 from n-type to p-type with a significant decrease in resistance. At the same time, the sensing performance of Fe2O3 octahedrons for volatile organic compound gases, especially toluene, is greatly improved. The 0.5 mol% Ni doped Fe2O3 sensor showed the highest response to toluene at 225°C (100 ppm, 47), which is five times higher than the pristine Fe2O3 (response 9.5). In addition, the sensor demonstrated fast response and recovery time (20 s/40 s), low detection limit (200 ppb), high moisture tolerance (98% RH, 47), and long-term stability of over 60 days. The main reason for the exceptional performance of Ni doped Fe2O3 sensors is its special porous octahedral structure, and more importantly, the change of carrier type of the sensing material after Ni doping and the substantial increase of oxygen vacancies, and the catalytic effect of Ni ions.

Climate Adaptation Analysis and Comfort Optimization Strategies for Traditional Residential Buildings in Hot-Summer, Cold-Winter Regions: A Case Study in Xuzhou, China

Climate change and the energy crisis have catalyzed the architectural industry’s consideration of green and energy-efficient buildings. With the continuous deepening and expansion of research, people have gradually realized the reference value of the passive design strategies embedded in traditional residential buildings for contemporary architectural design and renovation. This paper takes the traditional residential buildings on Hubu Mountain, Xuzhou, as its research object, and explores their thermal and wind environment characteristics through field investigations and software simulation analysis. It is found that Xuzhou’s traditional houses have good temperature regulation, with fluctuations of about 5 °C indoors and 10 °C outdoors in summer and about 7 °C indoors and 12 °C outdoors in winter. Their form, material and structure are well adapted to the local climate. There is also a need to optimize the buildings’ moisture resistance and ventilation for better comfort. Subsequently, this study analyzes the climate adaptability features in traditional building construction techniques and then extracts climate adaptability methods, proposing targeted optimization and renovation suggestions, aiming to contribute to the sustainable development of architecture and ecology.

Plasma enhanced atomic layer deposition of silicon nitride using magnetized very high frequency plasma

To obtain high-quality SiN x films applicable to an extensive range of processes, such as gate spacers in fin field-effect transistors (FinFETs), the self-aligned quadruple patterning process, etc, a study of plasma with higher plasma density and lower plasma damage is crucial in addition to study on novel precursors for SiN x plasma-enhanced atomic layer deposition (PEALD) processes. In this study, a novel magnetized PEALD process was developed for depositing high-quality SiN x films using di(isopropylamino)silane (DIPAS) and magnetized N2 plasma at a low substrate temperature of 200 °C. The properties of the deposited SiN x films were analyzed and compared with those obtained by the PEALD process using a non-magnetized N2 plasma source under the same conditions. The PEALD SiN x film, produced using an external magnetic field (ranging from 0 to 100 G) during the plasma exposure step, exhibited a higher growth rate (∼1 Å/cycle) due to the increased plasma density. Additionally, it showed lower surface roughness, higher film density, and enhanced wet etch resistance compared to films deposited using the PEALD process with non-magnetized plasmas. This improvement can be attributed to the higher ion flux and lower ion energy of the magnetized plasma. The electrical characteristics, such as interface trap density and breakdown voltage, were also enhanced when the magnetized plasma was used for the PEALD process. Furthermore, when SiN x films were deposited on high-aspect-ratio (30:1) trench patterns using the magnetized PEALD process, an improved step coverage of over 98% was achieved, in contrast to the conformality of SiN x deposited using non-magnetized plasma. This enhancement is possibly a result of deeper radical penetration enabled by the magnetized plasma.

Structure and properties of starch - BaSO4 composite obtained using mechanical activation techniques

The aim of this study is to obtain and characterize starch films structurally modified by in situ precipitation of BaSO4 combined with mechanical activation of casting dispersion in a rotor-stator device. By the rheological method, it was found that the modification causes a decrease in the ability of casting dispersions to structure over time. Composite films with a filler content of 0 %–15 % (w/w) were characterized using optical and SEM microscopy, FT-IR spectroscopy, and tensile and moisture resistance testing data. The maximum increase in strength (by 70 %) and elongation at break (by 870 %) is achieved with a filler content of 5 % and 15 %, respectively. An increase in the filler content to 5 % causes an increase in starch recrystallization rate, but at concentrations above 5 % of BaSO4, it inhibits retrogradation. The films obtained by mechanical activation with optimized parameters were uniformly translucent, had lower water vapor permeability than films made from starch alone, had high flexibility, and did not warp or shrink. The developed high-performance, environmentally friendly method can be recommended for the large-scale production of starch-based composite materials.

Photo-Cross-Linked Fullerene-Based Hole Transport Material for Moisture-Resistant Regular Fullerene Sandwich Perovskite Solar Cells.

Despite the high efficiencies currently achieved with perovskite solar cells (PSCs), the need to develop stable devices, particularly in humid conditions, still remains. This study presents the synthesis of a novel photo-cross-linkable fullerene-based hole transport material named FT12. For the first time, the photo-cross-linking process is applied to PSCs, resulting in the preparation of photo-cross-linked FT12 (PCL FT12). Regular PSCs based on C60-sandwich architectures were fabricated using FT12 and PCL FT12 as dopant-free hole transport layers (HTLs) and compared to the reference spiro-OMeTAD. The photovoltaic results demonstrate that both FT12 and PCL FT12 significantly outperform pristine spiro-OMeTAD regarding device performance and stability. The comparison between devices based on FT12 and PCL FT12 demonstrates that the photo-cross-linking process enhances device efficiency. This improvement is primarily attributed to enhanced charge extraction, partial oxidation of the HTL, increased hole mobility, and improved layer morphology. PCL FT12-based devices exhibit improved stability compared to FT12 devices, primarily due to the superior moisture resistance achieved through photo-cross-linking.

Influence of Interface Modification on the Moisture Absorption and Thermal Resistance of Ramie Fiber/Degradable Epoxy Composites.

Natural fiber/degradable epoxy composites have received much attention for their advantages of low carbon emissions, low environmental pollution, and utilization of renewable resources. However, the poor interfacial bonding strength and inferior moisture resistance of natural fiber/degradable epoxy composites restrict their application areas. In order to improve the moisture and heat resistance of natural fiber/degradable epoxy resin-based composites, this study modified the surfaces of ramie fibers with hydroxylated carbon nanotubes, silane coupling agents, and sodium hydroxide, respectively. Three types of modified ramie fiber/degradable epoxy composites, namely F-CN-DEP, F-Si-DEP, and F-OH-DEP, were prepared using a winding forming process. The water absorption rate and short-beam shear strength of the materials were tested under different environments, and the fiber morphology and thermal-mechanical properties of the materials were investigated by scanning electron microscopy (SEM) and dynamic mechanical analysis (DMA). The results show that F-CN-DEP exhibited the lowest moisture absorption rate; the highest shear strength, of 43.8 MPa; and a glass transition temperature (Tg) of 121.7 °C. The results demonstrate that carbon nanotubes on the fiber surface can improve the interfacial stability of ramie fiber/degradable epoxy composites in humid and hot environments. These results give guidelines for the development of natural fiber/degradable epoxy composites.

Assessing the efficacy of alginate-encapsulated rejuvenators from soybean oil sludge and fatty acid for enhanced self-healing capacity of asphalt mixtures

The effectiveness of incorporating fatty acid (SSFA) and soybean oil sludge (SS) as rejuvenating agents, encapsulated via ionotropic gelation of alginate with calcium, was investigated in this study. Four variations of capsules were produced: C/SS0.1, C/SS0.2, C/SSFA0.1, and C/SSFA0.2, with rejuvenator/water ratios ranging from 0.1 to 0.2. These capsules were then introduced at 0.6% of the total weight into the mixture. Initial assessments focused on capsule properties and their incorporation into mixtures. Impact evaluations included void volume, tensile strength, moisture damage, stiffness, rutting, and fatigue life. The capsules exhibited resistance and uniformity, impacting void volume and enhancing resilient modulus, fatigue life, and moisture resistance. The self-healing potential was evaluated through dynamic loading using the Semicircular Bending Test and a 24-hour resting period. The capsules significantly enhanced self-healing levels, recording values of 169%, 72%, 109%, and 90% for C/SS0.1, C/SS0.2, C/SSFA0.1, and C/SSFA0.2 mixtures, respectively, compared to 62% for capsules-free mixtures.

A literature review on moisture resistance performance of bitumen modifiers

A literature review on moisture resistance performance of bitumen modifiers

Utilizing Waste Cotton/Pigeon Pea Stalk Fibers Composites for Enhanced Sound Absorption and Insulation in Automotive Interiors

ABSTRACT This study investigates the synthesis and characterization of composite materials, pigeon pea stem, and cotton fibers blended in different ratios such as 100/0, 70/30, 60/40, 50/50, 30/70, and 0/100. These composite materials were produced using a compression molding technique. According to ASTM standards, the acoustics, thermal conductivity, and physical characteristics of the composite samples were tested to assess their qualities. The impedance tube method detailed in ASTM E1050 was used to determine the sound absorption coefficients (SAC) for acoustics. The SAC values were measured at six frequencies such as 125, 250, 500, 1000, 2000, and 4000 Hz. The results showed that composite samples made from waste cotton and pigeon pea demonstrated sound absorption values of greater than 80%. Superior sound insulation and absorption, moisture absorption, fiber properties have also been demonstrated by waste composites. Especially, the waste cotton/pea stalk waste fiber composites achieved over 75% sound absorption, while the waste 28% composites performed well in terms of sound absorption, moisture absorption, and fiber properties. Even in humid conditions, the composite samples constructed from used cotton and pigeon pea stalks demonstrated good moisture resistance without reducing their insulating qualities. Soundproofing barriers are composite layers of foam or pigeon pea/cotton.

Moisture‐Resistant Orange Emitters with Near‐Unity Quantum Yield from Mn2+ Alloyed Vacancy‐Ordered Quadruple Perovskites

AbstractMn2+‐doped metal halide perovskites present remarkable optical properties in optoelectronic applications, although the realization of high efficiency and stability is still a challenge. In this work, a series of highly efficient and stable orange‐emitting Mn2+ alloyed Cs4Cd1‐xMnxBi2Cl12 single crystals are successfully synthesized via a hydrothermal reaction. Combined with the crystal structure and spectral characterization at 7 K, the site occupation of Mn2+ and defect emission are systematically discussed. Benefiting from the effective [BiCl6]3−→[MnCl6]4− energy transfer and lattice distortion, these single crystals exhibit a maximum internal and external quantum yield of ≈97% and ≈65% at 35% heavy doping level. Interestingly, these Mn2+‐alloyed single crystals exhibit remarkably waterproof stability, no decrease in emission intensity is observed after immersion in deionized water for 4 h. After soaking in deionized water for 100 days, the internal quantum yield can still maintain 44%, implying good chemical stability and moisture resistance due to the formation of protective BiOCl layer. This work provides new insights into the optimization mechanism for Mn2+ luminescence and overcoming the downside of their waterproofing in humid conditions.

Influence of Non-Melting Waste Plastics on Volumetric Properties and Performance of Asphalt Mixtures

The main objective of the study is to evaluate the impact of using polystyrene (PS) and polyethylene terephthalate (PET) plastics as an additive in asphalt mixtures. For this purpose, volumetric modification, moisture susceptibility along with performance variation at high, intermediate, and low temperature conditions were evaluated. Initially plastics were subjected to calorimeter analysis for assessing their melting characterization. Both PS and PET are included as dry mix additives individually at dosage levels of 3%, 6%, and 9% by weight of asphalt binder. Further, the changes in thermal properties of plastics occurring during mixture preparation were correlated to better understand the volumetric modification. PS, owing to its glass transition and partial amorphous nature, exhibited minimum deviation (<1%) from design air voids (4 ± 0.5%). PET was observed to increase the volumes of voids in mineral aggregate (VMA) and air void, owing to its crystalline nature. As regards performance, PS and PET modification enhanced the moisture resistance by 1.05 to 1.11 times the control mixture. The rutting tolerance index ( RTindex) value increased for all plastic modified mixtures from the indirect tensile asphalt rutting test (IDEAL RT) performed at 58°C. However, the intermediate temperature cracking tolerance index ( CTindex) at 19°C conveyed the high embrittled nature from plastic modification making the mixtures more susceptible to cracking. From the Gf versus l75 /m75 interaction diagram, it was conveyed that although addition of plastics improves the fracture toughness of asphalt mixtures, the ductile nature of mixtures is compromised. Also, PS and PET modification could not improve the ability of asphalt mixtures to resist thermal cracking, evaluated at −18°C.

Novel green/red oxyfluoride phosphors with excellent optical properties for near-UV excited white light emitting diode

Novel eye-sensitive Ba3Nb2O2F12(H2O)2:Tb3+ green and Ba3Nb2O2F12(H2O)2:Mn4+ red oxyfluoride phosphors with extremely strong absorption in the UV region were designed and synthesized by simple co-precipitation strategy. Particularly, Tb3+ ions were doped in this matrix for the first time, which greatly improves their absorption efficiency in the near ultraviolet region (367 nm) and emits sharp green light (544 nm). In addition, the Ba3Nb2O2F12(H2O)2:Mn4+ red phosphors have strong zero phonon line (ZPL) emission at 625 nm, which is conducive to improving the sensitivity of human eye and color purity. Meanwhile, the optical properties of the red phosphor are significantly enhanced via doping K+ cations as charge compensators. Crystal field environment and nephelauxetic effect of the as-prepared phosphors before and after K+ cation doping were systematically analyzed. Moreover, these synthesized red/green phosphors have good thermal stability and moisture resistance. Remarkably, the as-prepared Ba3Nb2O2F12(H2O)2:5%Mn4+ or K0.9Ba2.1Nb2O2F12(H2O)2:5%Mn4+ red phosphors can be directly mixed with the as-synthesized Ba3Nb2O2F12(H2O)2:13 %Tb3+ green phosphor coating on 365 nm near-ultraviolet LED chip to package WLED devices with excellent electroluminescence performance. These findings are conducive to opening an avenue for screening the unique structure of optical materials.

Doping with KBr to Achieve High-Performance CsPbBr3 Semitransparent Perovskite Solar Cells.

Wide-bandgap semitransparent perovskite photovoltaics are emerging as one of the ideal candidates for building-integrated photovoltaics (BIPV). However, surface defects in inorganic CsPbBr3 perovskite prepared by vapor deposition severely limit the optoelectronic performance of perovskite solar cells. To address this issue, a strategy of doping a trace amount of KBr into perovskite by vapor deposition is adopted, effectively improving the quality of the film, reducing surface defect concentration, and enhancing the transportation and extraction of charge carriers. Simultaneously, fully physical vapor deposition technology is employed to fabricate perovskite solar cells with an average visible light transmittance of 44%. These devices exhibited an ultrahigh open-circuit voltage of 1.55 V and a superior power conversion efficiency (PCE) of 7.28%, demonstrating excellent moisture and heat resistance. Moreover, the corresponding 5 cm × 5 cm modules achieve a PCE of 5.35% with great thermal insulation capability. This work provides an approach for fabricating highly efficient all-inorganic perovskite solar cells with high average visible light transmittance, demonstrating new insights into their application in building-integrated photovoltaics.