Environmental Relative Humidity Research Articles

Monitoring atmospheric corrosion under multi-droplet conditions by electrical resistance sensor measurement

This paper presents a novel approach to investigate atmospheric corrosion kinetics of carbon steel under multi-droplet conditions. A homemade climate chamber has been developed to accurately control and monitor environmental conditions, including temperature (T) and relative humidity (RH), during exposure. Carbon steel corrosion kinetics are monitored with a custom-designed Electrical Resistance (ER) sensor pair. Savitzky-Golay (S-G) based filtering technique has been used for the corrosion signal processing. In parallel, top-view droplet temporal evolution has been recorded by microscopic imaging and analyzed for both droplet size distribution and the solid-liquid contact angle. The droplet size distribution can typically be described with a power-law form curve. The curve shows a decrease in height and a concurrent expansion in width with progressive drying. The introduction of NaCl into the electrolyte and surface roughness variations have also been identified to substantially influence the carbon steel corrosion rate. A strong correlation between the corrosion rate derived from the ER monitoring method and the RH can be observed. Additionally, this correlation can be further expanded to droplet-based electrolyte conditions. This study offers valuable insights into the development of mechanistic and kinetic prediction models for atmospheric corrosion.

Maintaining the 2D Structure of MXene via Self-Assembled Monolayers for Efficient Lubrication in High Humidity.

MXene is considered as a promising solid lubricant due to facile shearing ability and tuneable surface chemistry. However, it faces challenges in high-humidity environments where excessive water molecules can significantly impact its 2D structure, thus deteriorating its lubricating properties. In this work, the self-assembled monolayers are formed on MXene by surface chlorination (MXene-Cl) and fluorination (MXene-F), and their friction behaviors in high/low humidity are investigated. The results indicate that MXene-F and MXene-Cl can maintain a relatively constant friction coefficient (CoF) (MXene-F ∼0.76, MXene-Cl ∼0.48) under both high (75%) and low (25%)-relative humidity (RH) environments. Meanwhile, the MXene-F and MXene-Cl display a lower CoF than the pristine MXene (MXene CoF∼1.18) in high humidity. The above phenomena are mainly attributed to the preservation of its 2D layered structure, the increased layer spacing, and superficial partial oxidation for SAMs-functionalized MXene under high humidity during friction. Interestingly, MXene-Cl with moderate water resistance has a lower CoF than that of MXene-F with complete water resistance. The nanostructured water adsorption capacity and larger interlayer spacing of MXene-Cl make it exhibit a lower CoF compared to MXene-F. The findings of this study offer valuable guidance for tailoring MXene by surface chemical functionalization as an efficient solid lubricant in high humidity.

Role of Molecular Water Layer State on Freezing Front Propagation Rate and Mode Studied with Thermal Imaging.

In this work, we study the relationship between the molecular water layer (MWL) and frost freezing onset and propagation. The progression of frost has been reported to be governed by various localized icing phenomena, including interdroplet ice bridging, dry zones, and frost halos. Reports studying the state of water on surfaces have revealed the presence of a thin nanometer water layer on a range of surfaces. Regardless of further investigations that show environmental humidity, temperature, and surface energy to affect the thickness of the MWL on surfaces, the influence of the MWL on frost nucleation and propagation has not yet been previously addressed in the literature. To study the effect of the MWL on surface freezing events, a range of surface-functionalized glass substrates were prepared. In situ monitoring of freezing events with thermal imaging allowed studying the effect of surface chemistry and environmental relative humidity (RH) on the thickness and continuity of the MWL. We argue that the observed icing nucleation and propagation kinetics are directly related to the presence and continuity of the MWL, which can be manipulated by controlling the environmental humidity and surface chemistry.

Corrosion of some metallic materials embedded in gypsum

AbstractIn the construction area, as well as in the restoration of old and historical buildings, different metallic materials are frequently in contact with gypsum plaster. Due to the high porosity of gypsum plaster, and particularly in high relative humidity environments, the risk of corrosion exists. In the present work, carbon, galvanized and stainless steel, as well as copper, were embedded in gypsum plaster (with varying water/gypsum ratios) and exposed to different environmental conditions, and the corrosion rate was assessed by electrochemical techniques. Stainless steel showed very low corrosion rates, carbon and galvanized steel showed considerable corrosion rates, and copper showed moderate corrosion rates. The higher the humidity, the higher the corrosion rate, independently of the water/gypsum ratio. A comparison with results obtained for the same materials embedded in mortar was performed. Except for stainless steel, the corrosion rates obtained in gypsum are higher than those obtained in mortar, being this difference up to two orders of magnitude. The differences in the pH of both matrices explained the lower corrosion rates measured in mortar.

Optimization of Above-ground Environmental Factors in Greenhouses Using a Multi-objective Adaptive Annealing Genetic Algorithm

The greenhouse environment represents a dynamic, nonlinear system characterized by hysteresis and is influenced by a myriad of interacting environmental parameters, posing a complex multi-variable optimization challenge. This study proposes a multi-objective adaptive annealing genetic algorithm to optimize above-ground environmental factors in greenhouses, addressing the challenges of variable environmental conditions and extensive heating and humidity infrastructure. Initially, after analyzing the multi-objective model of greenhouse above-ground environmental factors, including temperature, relative humidity, and CO2 concentration, a comprehensive multi-objective, multi-constraint model was developed to encapsulate these factors in greenhouse environments. Subsequently, the model optimization incorporated multi-parameter coding of decision variables, a fitness function, and an annealing dynamic penalty factor. Validation conducted at Yangling Agricultural Demonstration Park revealed that the application of multi-objective adaptive annealing genetic algorithms (schemes 1 and 2) significantly outperformed the single-objective genetic algorithm (scheme 3) and the traditional genetic algorithm (scheme 4). Specifically, the improvements included a reduction in average temperature rise by 2.64°C and 5.29°C for schemes 1 and 2, respectively, equating to 20% and 34% decreases. Additionally, average humidification reductions of 2.39% and 3.9% were observed, alongside decreases in the total lengths of heating and humidification pipes by up to 2.99 km and 0.443 km, respectively, with a maximum reduction of 14% in heating pipes. The integration of an annealing dynamic penalty factor enhanced the adaptive climbing ability of schemes 1 and 2, improving static stability and robustness. Furthermore, the number of iterations required to achieve convergence was reduced by approximately 170 to 240 times compared to schemes 3 and 4. This reduction in iterations also resulted in a significant decrease in running time by 5 to 13 minutes, corresponding to time savings of 31% to 56%, thereby achieving further optimization.

Durability of Fe-SMA/steel single-lap joints exposed to hygrothermal environments

Due to the adverse impact of hygrothermal environments and fatigue load, the performance degradation of existing steel structures necessitates repairs to extend their service life. Structures retrofitted by bonding iron-based shape memory alloy (Fe-SMA) have been demonstrated as an active non-destructive repair method. Nevertheless, the deterioration of the adhesives triggered by hygrothermal environments is a crucial challenge in its practical reinforcement applications. In this study, 54 Fe-SMA/steel single-lap joints (SLJs) are aged in 55°C and 98 % relative humidity environments for 30, 60 and 110 days, and tested under shear loads. The long-term performance, failure patterns, load-displacement responses and shear-resistance capacity of the SLJs are investigated, considering the essential parameters of aging time, overlap length and adhesive types. The experimental results exhibit that the failure patterns of aged Fe-SMA/steel SLJs depend highly on the adhesive types. The shear-resistance capacity of Fe-SMA/steel SLJs decreases dramatically with the prolongation of aging time. After 110 days of aging, the shear-resistance capacity of type-C, type-S and type-P SLJs decreases by about 14 %, 39 % and 49 %, respectively. When the overlap length increases from 50 mm to 150 mm, the shear-resistance capacity of type-C, type-S and type-P Fe-SMA/steel SLJs improves by 21 %, 39 % and 22 %, respectively, increasing the overlap length can safeguard the optimal functionality and long-term performance of the retrofitted steel structures. While the environments are relatively aggressive, it is recommended to use type-C adhesive to obtain the satisfactory serviceability of the retrofitted steel structures. The experimental achievements are significant for repairing deteriorated steel infrastructures by bonding Fe-SMA, guaranteeing the long-term performance and normal-use safety of structural reinforcement design, and reducing carbon emissions due to the avoidance of reconstruction.

Managing Interfacial Defects and Charge-Carriers Dynamics by a Cesium-Doped SnO2 for Air Stable Perovskite Solar Cells.

A high-quality nanostructured tin oxide (SnO2) has garnered massive attention as an electron transport layer (ETL) for efficient perovskite solar cells (PSCs). SnO2 is considered the most effective alternative to titanium oxide (TiO2) as ETL because of its low-temperature processing and promising optical and electrical characteristics. However, some essential modifications are still required to further improve the intrinsic characteristics of SnO2, such as mismatch band alignments, charge extraction, transportation, conductivity, and interfacial recombination losses. Herein, an inorganic-based cesium (Cs) dopant is used to modify the SnO2 ETL and to investigate the impact of Cs-dopant in curing interfacial defects, charge-carrier dynamics, and improving the optoelectronic characteristics of PSCs. The incorporation of Cs contents efficiently improves the perovskite film quality by enhancing the transparency, crystallinity, grain size, and light absorption and reduces the defect states and trap densities, resulting in an improved power conversion efficiency (PCE) of ≈22.1% with Cs:SnO2 ETL, in-contrast to pristine SnO2-based PSCs (20.23%). Moreover, the Cs-modified SnO2-based PSCs exhibit remarkable environmental stability in a relatively higher relative humidity environment (>65%) and without encapsulation. Therefore, this work suggests that Cs-doped SnO2 is a highly favorable electron extraction material for preparing highly efficient and air-stable planar PSCs.

A novel dynamic simulation method for investigating the hygroscopicity of Ammonium perchlorate

Ammonium perchlorate (AP) is a widely used oxidizer, extensively employed in solid propellants with excellent combustion properties. Ultrafine AP has better combustion properties, but its strong hygroscopicity and high sensitivity hinder its application. To safely and efficiently explore the hygroscopicity of ultrafine AP, this paper proposes a novel molecular dynamics (MD) simulation approach. By analyzing the movement of water molecules, fluctuations in average hydrogen bond strength, and the influence of non-covalent intermolecular forces throughout the moisture absorption process, this study presents a comprehensive overview of the hygroscopic properties of ultrafine AP across relative humidity (RH) levels spanning from 10 % to 100 %, and temperatures ranging between 273 K and 373 K. It was found that temperature has a more significant impact on the hygroscopicity of AP compared to RH. During the hygroscopic process of AP, Van der Waals interactions hindered the water absorption of AP, while electrostatic forces promoted its hygroscopic properties. The hygroscopicity of AP reached a maximum when the temperature exceeded 333 K, and plateaued as the increase of RH. The proposed moisture simulation method facilitates the secure and effective forecasting of moisture absorption in AP-based materials across various temperature and RH environments, thereby greatly expediting research on enhancing the moisture resistance of ultrafine AP.

THE EFFECT OF WATER DOUSING ON HEAT STRAIN AND PERFORMANCE DURING ENDURANCE RUNNING IN THE HEAT

INTRODUCTION Water dousing (pouring water on the body) is an easy-to-implement cooling method while running due to the availability of water at race aid stations, and may decrease the risk of heat illness and improve performance. However, dousing has not been investigated in extended duration running (i.e., ≥10 km), a typical distance in both elite and community level events. AIMS: Assess the effect of water dousing on heat strain and performance during self-paced and fixed-intensity exercise in the heat. DESIGN: Crossover, block randomised controlled trial. METHODS 13 trained runners completed a 10 km time trial (TT) and 60 min fixed pace run (60% velocity of VO2max) in a 30°C, 47% relative humidity environment using either water dousing (DOUSE) or no dousing (CON). RESULTS 10 km TT performance was faster in DOUSE compared to CON (44:11±6:14 vs. 44:38±6:03 min:s; p=0.033). Change in core temperature (Tc) was not different between groups during the TT (+0.02±0.33°C in DOUSE; p=0.853) or fixed pace run (+0.02±0.30°C; p=0.848). Change in mean skin temperature (Tsk) was lower in DOUSE during the TT (-1.80±0.63°C; p<0.001) and fixed pace run (-1.38±0.78°C; p<0.001). Heart rate (HR) was lower for DOUSE during the fixed pace run (-3.5±5.5 bpm; p=0.041) but not during the TT (-0.2±4.2 bpm; p=0.853). Thermal sensation was lower for DOUSE during the TT (-49.3±41.9 mm; p<0.001) and fixed pace run (-44.7±27.6 mm; p<0.001). Rating of perceived exertion (RPE) was not different between groups for the TT (-0.2±0.9; p=0.390) or fixed pace run (-0.2±1.0; p=0.480). CONCLUSION Water dousing improves 10 km TT performance in the heat but does not mitigate a rise in Tc. The positive change in thermal perception (via lower skin temperature) likely drives this ergogenic effect.

Ad Libitum Drinking Prevents Body Mass Loss Across Consecutive Workdays in Heat

Hydration practices across consecutive days of heavy-intensity work in heat when fluid is freely available is unknown. Without this information it remains unknown whether hydration modifies heat strain under hot working conditions and whether worker recommendations adequately maintain hydration status. We hypothesized that participants would maintain hydration status including daily percent change in body mass across workdays. Fifteen healthy, unacclimated participants (7 Females, Age: 27±6 y, Body mass: 75.0±14.4 kg, Body fat: 26.6±5.8%) completed three consecutive days (Day 1, Day 2, Day 3) of 4 h of 395±10 W work to a work/rest cycle of 45/15 min in a 36.3±0.8°C, 21±5% relative humidity environment. Participants were offered 237 mL of a sport drink every 20 min to consume ad libitum. Urine flow rate (UFR) was measured before work. Urine specific gravity (USG) and nude body mass were measured before and after work. Thirst and fluid consumption were measured throughout work. USG before work was not different between Day 1 (1.013±0.010) and Day 2 (1.013±0.010, p=0.822), but was greater before work on Day 3 (1.015±0.010, p=0.046) compared to Day 2. Change in USG from before to after work was not different between Day 1 (+0.003±0.008) and Day 2 (+0.000±0.006, p=0.123), but was lower on Day 3 (-0.002±0.006, p=0.021) compared to Day 1, with no difference between Day 2 and Day 3 (p=0.058). Before work body mass was not different across days (p=0.103). Daily percent change in body mass was not different across days (p=0.366, Day 1: 0.53±1.11%, Day 2: 0.18±0.95%, Day 3: 0.18±0.81%), indicating weight gain each day. Sweat rate (p=0.790) and UFR (p=0.469) were not different among days. Participants consumed 77±18% (Day 1), 82±19% (Day 2), and 82±16% (Day 3) of fluid offered (p=0.401), equaling 31±10 mL/kg (Day 1), 33±11 mL/kg (Day 2), 33±10 mL/kg (Day 3) (p=0.370). Maximum thirst was greater on Day 1 (3.5±1.1) compared to Day 3 (2.9±1.0, p=0.045) with no difference between Day 1 and Day 2 (3.4±1.4, p=0.648) or between Day 2 and Day 3 (p=0.121). This study demonstrates consistent hydration practices and no differences in hydration status across three consecutive days of high-intensity work in heat when fluid is freely available. Under these conditions, workers can consume fluids ad libitum and worker recommendations for hydration during heat stress should be revisited. This project was funded my the National Institute for Occupational Safety and Health (1K01OH012016-01A1). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Cold-water foot immersion and physiological strain of adults with coronary artery disease during hot and humid heat exposure

Introduction: Heat extremes are associated with a greater risk of adverse cardiovascular outcomes, especially among adults with coronary artery disease. While air-conditioning provides exceptional protection during heat extremes, it is neither sustainable nor widely accessible. Cold-water foot immersion reduces physiological heat strain in healthy young adults but its effect in more vulnerable populations remains unknown. Objective and hypotheses: This study aims to identify the effect of cold-water foot immersion on markers of physiological heat strain in adults with coronary artery disease. We hypothesized that cold-water foot immersion would reduce physiological heat strain when used on its own and that this effect would be greater when combined with an electric fan. Methods: 17 adults living with stable coronary artery disease (2 females/15 males; 67±8 years) were exposed to a 38°C, 60% relative humidity environment for 3 hours on three separate, randomized occasions: i) no cooling (control; CON); ii) cold-water foot immersion (20 min of immersion each 30 min, ~30 cm in water kept at ~18°C; FI); iii) cold-water foot immersion and fan use (FI+FAN). Rectal and skin temperatures, heart rate (5-lead ECG), and whole-body sweat loss (change in nude weight) were measured. Results: The increase in rectal temperature did not differ between conditions (CON: 0.40±0.24°C, FI: 0.41±0.29°C, and FI+FAN: 0.36±0.22°C; p≥0.49). The increase in skin temperature was reduced with FI and FI+FAN compared to CON (CON: 4.9±0.8°C, FI: 4.1±1.2°C, and FI+FAN: 4.3±0.8°C; p≤0.01), with no difference between FI and FI+FAN (p=0.15). Similarly, the increase in heart rate was reduced with FI and FI+FAN compared to CON (CON: 8±6 bpm, FI: 4±6 bpm, and FI+FAN: 3±6 bpm; p≤0.01), with no difference between FI and FI+FAN (p=0.45). Sweat loss was also reduced by FI and FI+FAN compared with CON (CON: 823±114 g, FI: 544±174 g, and FI+FAN: 671±255 g; p≤0.03), with sweat loss during FI sweat loss being lower than during FI+FAN (p=0.03). Conclusion: The results show that cold-water foot immersion, used alone or in combination with an electric fan, reduces the increase in heart rate and whole-body sweat loss of adults living with coronary artery disease exposed to a hot and humid environment for 3 hours. This could be linked to the lower increase in skin temperature with foot immersion. National Health and Medical Research Council of Australia (APP1147789). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

La/SnO2 nanoparticles: Hydrothermal synthesis, structure, and sensing performance in a high relative humidity environment

In this work, a simple one-step hydrothermal synthesis of La doped SnO2 nanocomposites was studied. The structure, morphology, specific surface area, and chemical composition were determined by XRD, SEM, BET, and XPS techniques. The gas sensing performance of SnO2 and La/SnO2 nanocomposites with varied La doping dosages on n-butanol gas was systematically investigated. The results manifested that under the testing environment (50 % relative humidity and 30 °C), La doped SnO2 nanocomposite sensor presented high response (69), excellent selectivity, good repeatability and long-time stability to n-butanol gas at 160 °C. Especially, the 7 mol% La doped SnO2 sensor displayed a 5.9 times higher response to 50 ppm n-butanol than the SnO2 sensor. In comparison with bare SnO2, La doping increased the band gap value of 7 mol% La/SnO2 nanocomposite by 6.23 %, decreased particle size by 11.83 %, and increased the oxygen defect concentration by 6.07 %. Due to the synergistic effect of the above factors, the gas sensing performance of La doped SnO2 nanocomposites towards n-butanol gas was enhanced. Therefore, La doped SnO2 nanocomposites might be a potential gas sensing material for monitoring n-butanol gas at relatively high humidity.

Characteristics and health impacts of bioaerosols in animal barns: A comprehensive study

Bioaerosols produced during animal production have potential adverse effects on the health of workers and animals. Our objective was to investigate characteristics, antibiotic-resistance genes (ARGs), and health risks of bioaerosols in various animal barns. Poultry and swine barns had high concentrations of airborne bacteria (11156 and 10917 CFU/m3, respectively). Acinetobacter, Clostridium sensu stricto, Corynebacterium, Pseudomonas, Psychrobacter, Streptococcus, and Staphylococcus were dominant pathogenic bacteria in animal barns, with Firmicutes being the most abundant bacterial phylum. Based on linear discriminant analysis effect size (LEfSe), there were more discriminative biomarkers in cattle barns than in poultry or swine barns, although the latter had the highest abundance of bacterial pathogens and high abundances of ARGs (including tetM, tetO, tetQ, tetW sul1, sul2, ermA, ermB) and intI1). Based on network analyses, there were higher co-occurrence patterns between bacteria and ARGs in bioaerosol from swine barns. Furthermore, in these barns, relative abundance of bacteria in bioaerosol samples was greatly affected by environmental factors, mainly temperature, relative humidity, and concentrations of CO2, NH3, and PM2.5. This study provided novel data regarding airborne bio-contaminants in animal enclosures and an impetus to improve management to reduce potential health impacts on humans and animals.

Temporal and Spatial Foraging Activity of Indian Honey Bee (Apis cerana indica F.) at Different Migratory Sites

Migratory beekeeping increases honey production and reduces the feeding costs of stationary beekeeping during longer dearth periods. This study discerns the influence of environmental conditions on the foraging behavior of the Indian honey bee, Apis cerana indica F., at different migratory sites in Southern India. The total number of foraging bees, pollen foraging efficiency, and nectar foraging efficiency were estimated. Furthermore, the influence of environmental factors, including temperature, relative humidity, rainfall, and solar radiation, was recorded to identify its impact on the foraging behavior of honey bees. Among the climatic factors, maximum temperature (>30 °C) was the most crucial, negatively affecting bee activity with correlation coefficients of -0.83, -0.34, and -0.33 for outgoing bees, nectar, and pollen collectors, respectively. The relative humidity showed a positive impact on the frequency of worker bees moving out of the hive (r = 0.79), those coming in with nectar (r = 0.27), and pollen (r = 0.29). Rainfall hampered foraging activity, while solar radiation was found to have no significant effect on bee activity. Diurnal variations showed peak activity of bee foragers between 6.00 and 10.00 am. The visits by honey bees were significantly higher at low temperatures, solar radiation, precipitation, and high relative humidity. They made about 90% of their flower visits in the early morning, although plenty of bee flora was available throughout the day. Also, the environmental conditions at different sites strongly influenced the foraging behavior. However, the honey bees still focused their activities on favorable conditions depending on their biology and fixed their daily foraging patterns, improving beekeeping and honey production throughout the year.

Facile Preparation of Impalement Resistant, Mechanically Robust and Weather Resistant Photothermal Superhydrophobic Coatings for Anti-/De-icing.

Photothermal superhydrophobic coatings hold great promise in addressing the limitations of conventional superhydrophobic anti-icing coatings. However, developing such coatings with excellent impalement resistance, mechanical robustness and weather resistance remains a significant challenge. Here, we report facile preparation of robust photothermal superhydrophobic coatings with all the above advantages. The coatings were prepared by spraying a dispersion consisting of fluorinated silica nanoparticles, a silicone-modified polyester adhesive and photothermal carbon black nanoparticles onto Al alloy plates followed by thermal curing. Thermal curing caused migration of perfluorodecyl polysiloxane from within the coatings to the surface, effectively maintaining a low surface energy despite the presence of the adhesive. Therefore, combined with the hierarchical micro-/nanostructure, dense yet rough nanostructure, adhesion of the adhesive and chemically inert components, the coatings exhibited remarkable superhydrophobicity, impalement resistance, mechanical robustness and weather resistance. Furthermore, the coatings demonstrated excellent photothermal effect even in the -10 °C, 80 % relative humidity and weak sunlight (0.2 sun) environment. Consequently, the coatings showed excellent passive anti-icing and active de-icing performance. Moreover, the coatings have good generalizability and scalability. We are confident that this study will accelerate the practical implementation of photothermal superhydrophobic coatings.

Deterioration of steel structures due to corrosion considering the global effects of climate change

The randomness of atmospheric conditions is among the key contributing factors that affect the ability to accurately predict the corrosion growth in steel structures. Climate change has the potential to alter the long-term characteristics of these factors over the lifespan of steel structures, both those already existing and those newly built. The impact of climate variability on the stochastic nature of atmospheric variables, which greatly influence corrosion conditions, can add complexity to corrosion predictions in these structures. This paper introduces an integrated framework to quantify the impact of climate change on corrosion rates of steel structures worldwide. It considers the changes in environmental conditions, specifically temperature, relative humidity and wind speed and their effects on atmospheric corrosion. Global Climate Models are employed to evaluate the long-term impacts of climate change on these environmental conditions. An analytical model for predicting corrosion rate is integrated with climate change models to predict alterations in the corrosion rates of steel components relative to historical conditions. This paper also discusses the impact of climate change on the variations of these climatic parameters and offers a comparison between historical data and projected conditions across the globe. The results indicate that the effect of climate change on the corrosion rate depends on the considered region. While regions such as Australia, North America and Europe see an increase, others such as Asia and Africa observe a decline. Notably, all oceans, especially the Antarctic and Arctic, experience a significant increase in corrosion by the end of the century.

The role of air relative humidity on the wettability of Pseudomonas fluorescens AR11 biofilms

Biofilms are complex porous materials formed by microorganisms, polysaccharides, proteins, eDNA, inorganic matter, and water. They are ubiquitous in various environmental niches and are known to grow at solid-liquid, solid-air and air-liquid interfaces, often causing problems in several industrial and sanitary fields. Their removal is a challenge in many applications and numerous studies have been conducted to identify promising chemical species as cleaning agents. While these substances target specific components of biofilm structure, the role of water content in biofilm, and how it can influence wettability and detergent absorption have been quite neglected in the literature. Estimating water content in biofilm is a challenging task due to its heterogeneity in morphology and chemical composition. In this study, we controlled water content in Pseudomonas fluorescens AR 11 biofilms grown on submerged glass slides by regulating environmental relative humidity after drying. Interfacial properties of biofilm were investigated by measuring wetting of water and soybean oil. The morphology of biofilm structure was evaluated using Confocal Laser Scanning Microscopy and Scanning Electron Microscopy. The results showed that biofilm water content has a significant and measurable effect on its wettability, leading to the hypothesis that a preliminary control of water content can play a crucial role in biofilm removal process.

Fabrication of Highly Efficient and Ambient Stable Planar MAPbI3 Perovskite Solar Cells via Defect Passivation through Crosslinking Strategy

Iodine‐based hybrid planar perovskite solar cells’ (PSCs) overall performance is still very limited. In this work, a highly functionalized iodine‐based hybrid perovskite layer is fabricated by incorporating trimethylolpropane ethoxylated triacrylate (TET) within the perovskite precursor, which can crosslink with the grain boundaries to improve the crystallinity as well as the grain size and passivate the defect states of the perovskite material. The MAPbI3‐based thin films with TET exhibited large grain sizes from 195.73 to 587.49 nm with 8 mg mL−1 of TET concentration. The X‐ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), energy dispersive X‐ray (EDX) elemental mapping, photoluminescence (PL), and time resolved photoluminescence (TRPL) characterization results suggest the strong crosslinking effect between TET and MAPbI3, which improves the crystallinity and reduces the charge trap density. Planar PSCs is fabricated with the device architecture fluorine‐doped tin oxide (FTO)/c‐TiO2/MAPbI3:TET/Spiro‐MeOTAD/Au and achieved a power conversion efficiency (PCE) of 14.75% under 1.5 AM light illumination. The fabricated PSCs shows excellent ambient stability which retains 80% of their PCE after being exposed to the ambient environment of relative humidity (RH) ≈60%, room temperature (RT) ≈27 °C without any encapsulation.

3D hierarchical microcubic morphological composite and its application for Bi-functional Humidity/Pressure sensing in TENG architecture

Harnessing the power of contact electrification, triboelectric nanogenerators (TENGs) are a cutting-edge energy technology, where output performance is greatly influenced by the micro/nano scale architectures of triboelectric layers. We present a study on the development of TENG by introducing an advanced 3D hierarchical microcubic morphological structure prepared by simple solution casting method, employing a renewable material, lignin, in combination with eco-friendly polyvinyl alcohol (PVA) matrix. The strategic incorporation of epichlorohydrin (EPCH) as a crosslinker enhances thermal stability, and crosslinking within the lignin/PVA composite (LPC) film. A remarkable outcome of this integration is the emergence of a 3D hierarchical microcubic structure within the LPC film. This structure, with its intricate 3D arrangement, emerges as the cornerstone that underpins the development of LPC-TENGs devices distinguished by their simple fabrication process, elevated output performance, and multifaceted applications. The LPC-TENG, adorned with its unique 3D hierarchical microcubic architecture, establishes new standards in energy harvesting and sensing capabilities with a maximum output power density of 135.4 mWm−2, a short-circuit current of 6.44 μA, and a maximum output voltage of 65 V (5 times higher than PVA-based TENGs). Additionally, the LPC-TENG showed exceptional performance as a self-powered bifunctional sensing system, providing a steady output voltage range of 0–10 V across various humidity levels (20–90 % RH) and a wide usable pressure range (0–162 kPa) with a low detection limit of 1 kPa. We demonstrated the application of the LPC-TENG in energy harvesting from human walking, enabling simultaneous measurements of environmental relative humidity, pressure, and illumination of 27 commercial LEDs. The unique 3D hierarchical microcubic architecture offers an unparalleled foundation for accommodating overall performance and diverse sensing functionalities.

The impact of short-term exposure to meteorological factors on the risk of death from hypertension and its major complications: a time series analysis based on Hefei, China.

This study aimed to reveal the short-term impact of meteorological factors on the mortality risk in hypertensive patients, providing a scientific foundation for formulating pertinent prevention and control policies. In this research, meteorological factor data and daily death data of hypertensive patients in Hefei City from 2015 to 2018 were integrated. Time series analysis was performed using distributed lag nonlinear model (DLNM) and generalized additive model (GAM). Furthermore, we conducted stratified analysis based on gender and age. Relative risk (RR) combined with 95% confidence interval (95% CI) was used to represent the mortality risk of single day and cumulative day in hypertensive patients. Single-day lag results indicated that high daily mean temperature (T mean) (75th percentile, 24.9°C) and low diurnal temperature range (DTR) (25th percentile, 4.20°C) levels were identified as risk factors for death in hypertensive patients (maximum effective RR values were 1.144 and 1.122, respectively). Extremely high levels of relative humidity (RH) (95th percentile, 94.29%) reduced the risk of death (RR value was 0.893). The stratified results showed that the elderly and female populations are more susceptible to low DTR levels, whereas extremely high levels of RH have a more significant protective effect on both populations. Overall, we found that exposure to low DTR and high T mean environments increases the risk of death for hypertensive patients, while exposure to extremely high RH environments significantly reduces the risk of death for hypertensive patients. These findings contribute valuable insights for shaping targeted prevention and control strategies.