Changes In Humidity Research Articles

Enhanced humidity sensing properties of Ta2O5 and ITO doped rutile-TiO2 porous ceramics

In this study, we investigated the humidity sensing properties of TiO2-based ceramics doped with tantalum pentoxide (Ta2O5) and indium tin oxide (ITO). Pure TiO2, 1%Ta-doped TiO2 (1%TTO), 1%ITO-doped TiO2 (1%ISTO), and 1%(Ta2O5 + ITO) co-doped TiO2 (1%ISTTO) ceramic samples were obtained by sintering at 1200 °C for 3 h. The rutile phase was observed in all samples. The lattice parameters of the single and co-doped samples were larger than those of pure TiO2, confirming the substitution of dopants. Porosity was observed in all ceramics. The mean grain sizes of all doped samples were significantly reduced compared to undoped TiO2. A homogeneous element dispersion was observed in the 1%TTO and 1%ISTTO ceramics, while segregation particles of related In-rich elements was observed in the 1%ISTO ceramic. Giant dielectric properties were not achieved in any samples due to the porosity. Nevertheless, excluding the undoped TiO2, the dielectric properties of all porous ceramics varied significantly with changes in humidity. The 1%ISTTO ceramic demonstrated superior humidity sensing properties, including a low maximum hysteresis error of 3.6% at 102 Hz. In contrast, the 1% TTO and 1% ISTO ceramics showed higher maximum hysteresis errors of 7.2% and 19.8%, respectively. Notably, the response and recovery times were 7.05 ± 0.18 and 2.48 ± 0.39 min, respectively, with good repeatability. This improvement is likely due to the synergistic effect of oxygen vacancies and TaTi·\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\ ext{Ta}}_{{{\ ext{Ti}}}}^{ \\cdot }$$\\end{document} defects on the surface, enhancing the humidity sensing properties of the 1% ISTTO ceramic, coupled with its optimal microstructure due to its lowest porosity and grain size.

Evolution of megadrought and pluvial events in the Qaidam Basin and Hexi Corridor, Northwest China, during the period 455–2100 CE

AbstractMillennium‐long hydroclimate reconstructions in the Qaidam Basin (QB) and Hexi Corridor (HXC) suggest markedly differing moisture change trends between the two regions in the 20th century; however, it remains unclear whether these current moisture states are exceptional in a long‐term context, and how megadrought and pluvial events have evolved in these regions. Here, we used previously published historical hydroclimate reconstructions combined with model‐based future moisture simulations to assess past, current and future hydroclimate anomalies in a long‐term context (i.e., 455–2100 CE), and investigate the evolution of megadrought and pluvial events. Compared with the QB, moisture variability in the HXC was higher and more prone to the occurrence of severe and long‐lasting megadrought and pluvial events. Megadroughts in the QB mainly occurred in the Little Ice Age (1200–1800 CE) accompanied by lower temperatures, whereas in the HXC, megadroughts mostly occurred during the Medieval Climate Anomaly (800–1200 CE) accompanied by higher temperatures. The Significant Zero crossing of derivatives (SiZer) and Time of Emergence (TOE) analyses were used to reveal the initiation of recent humidity changes and the duration above the natural variability threshold. We found that the QB has experienced a significant wetting trend since the middle of the 20th century, with this trend exceeding the range of natural hydroclimate variability in 1975 CE. The HXC became drier from the early 20th century, but has become wetter since the late 20th century; this trend may exceed the natural hydroclimate variability range by 2032 CE. We also found that the duration and severity of megadrought and pluvial events are positively correlated in each region. Given the higher past hydrological variability in the HXC compared with the QB, our study implies that future extreme hydrological events are more likely to occur in the former of these two regions.

The role of water in APCI-MS online monitoring of gaseous n-alkanes

In atmospheric pressure chemical ionization mass spectrometry (APCI-MS), [M−3H+H2O]+ ions can deliver analyte-specific signals that enable direct analysis of volatile n-alkane mixtures. The underlying ionization mechanisms have been the subject of open debate, and in particular the role of water is insufficiently clarified to allow for reliable process analytics when the humidity level changes over time. This can be a problem, particularly in online monitoring, where analyte accumulation in the ion source can also occur. Here, we investigated the role of water during APCI-MS of volatile n-alkanes by changing the carrier gas for sample injection from a dry to a wetted state as well as by using 18O-labeled water. This allowed for a distinction between gaseous and surface-adsorbed water molecules. While adsorbed water seems to be responsible for the desired [M−3H+H2O]+ signals through surface reactions with the analyte molecules, gaseous water was found to promote the formation of CnH2n+1O+ of different (and analyte-independent) hydrocarbons, revealing a reaction with hydrocarbon species which accumulated in the ion source during continuous operation. At the same time, gaseous water competed with analyte molecules for ionization and thus suppressed the formation of alkyl (CnH2n+1+) and alkenyl (CnH2n−1+) ions. The results reveal a memory effect due to hydrocarbon adsorption, which may cause severe interpretation difficulties when the ionization chamber undergoes sudden humidity changes. The use of [M−3H+H2O]+ for n-alkane analysis in alkane/water mixtures can be facilitated by constantly maintaining high humidity and hence stabilizing the ionization conditions.Graphical abstract

The impact of heat and humidity changes on laboratory acoustic measurements through perturbation method

The paper relates to the determination of the influence of changes in temperature and relative humidity on the laboratory acoustic measurements results. A series of direct reverberation time measurements was carried out, applying different thermal and humidity conditions in the empty reverberation chamber and reverberation chamber with a sound absorber. The reverberation chamber is mainly used to tests aimed at assessment construction materials and products. The results of acoustic measurements and the related classification of construction materials and products ultimately translate into the comfort and acoustic quality of rooms with special requirements as well as living rooms. Based on the analysis of the results, the significance of the problem related to the influence of air parameters on the results of measurements was demonstrated. The effect of changes in temperature and humidity on the results of calculating the equivalent sound absorbing surface was estimated using the n-perturbation method.

Inkjet-Printed Bio-Based Melanin Composite Humidity Sensor for Sustainable Electronics.

A lack of sustainability in the design of electronic components contributes to the current challenges of electronic waste and material sourcing. Common materials for electronics are prone to environmental, economic, and ethical problems in their sourcing, and at the end of their life often contribute to toxic and nonrecyclable waste. This study investigates the inkjet printing of flexible humidity sensors and includes biosourced and biodegradable materials to improve the sustainability of the process. Humidity sensors are useful tools for monitoring atmospheric conditions in various fields. Here, an aqueous dispersion of black soldier fly melanin was optimized for printing with a cosolvent and deposited onto interdigitated silver electrodes on flexible substrates. Impedance spectroscopy demonstrated that adding choline chloride increased the ion concentration and AC conductivity by more than 3 orders of magnitude, resulting in a significant improvement in sensing performance and reduced hysteresis. The devices exhibit fast detection (0.8 ± 0.5 s) and recovery times (0.8 ± 0.3 s), with a 170 ± 40-fold decrease in impedance for relative humidity changes from 30% to 90%. This factor is lowered upon prolonged exposure to high humidity in tests over 72 h during which a stable operation is reached. The low embodied energy of the sensor, achieved through material-efficient deposition and the use of waste management byproducts, enhances its sustainability. In addition, approaches for reusability and degradability are presented, rendering the sensor suitable for wearable or agricultural applications.

Managing Green and Sustainable Technologies: Climate-Informed Corrosion Prediction for Steel Structures

The unpredictability of atmospheric circumstances is one of the major elements that contribute to the capability to anticipate the corrosion growth in metal structures over time accurately. Climate shifts can potentially modify the long-term attributes of these factors throughout the operational life of metal structures, both those currently in existence and those newly developed. The impact of climate irregularity on the probabilistic nature of atmospheric variables, which significantly impact corrosion situations, can add intricacy to corrosion predictions in these constructions. This project presents an incorporated framework to quantify the impact of climate alteration on the corrosion rates of steel structures in Jordan. It considers the changes in environmental conditions, specifically temperature, relative humidity, and wind speed, and their impacts on atmospheric corrosion. Global Climate Models are employed to assess the long-term effects of climate transformation on these environmental circumstances. An analytical model for anticipating corrosion rate is integrated with climate transformation models to predict modifications in the corrosion rates of steel parts relative to historical situations. This project also examines the impact of climate transformation on the fluctuations of these climatic parameters and offers a contrast between historical data and projected conditions across the country. The findings indicate a significant increase in corrosion rates across Jordan, which calls for localized green building codes and standards to ensure that future infrastructure is sustainable and capable of withstanding the new climatic norms. This approach addresses the immediate challenges posed by climate change and contributes to the broader goals of sustainable urban development and managing green technology adoption in Jordan. Doi: 10.28991/CEJ-2024-010-08-016 Full Text: PDF

Ultra-sensitive humidity sensing based on Coherent perfect absorber-lasing system

Abstract As a singularity in non-Hermitian physics, coherent perfect absorber-lasing (CPAL) point theoretically has an infinite quality factor and can detect small perturbations, so it has potential applications in ultra-sensitive sensors. However, in the radio frequency field, due to deviations in actual components, the system will deviate from the CPAL point and the performance will degrade significantly (the output coefficient amplitude is only 30 dB). At the same time, actual sensing research is also very lacking. Based on these, we demonstrate a CPAL-based sensor system that increases its output coefficient amplitude to 60dB. When using the lasing state as the sensing mode, it has a capacitance detection accuracy of 10 fF. Then a high-frequency capacitive humidity sensor based on polyaniline/graphene oxide/titanium dioxide film is designed. The heterojunction formed between these materials increases the number of active sites for adsorbing water molecules. With the ultra-high capacitance detection accuracy of the CPAL sensor system, it is finally able to distinguish a 1% relative humidity change at 20%RH (corresponding to a 20 fF capacitance change, or a 1.63 dB output coefficient change), showing potential sensing application prospects.

Preparation and characterization of UV-curable coatings based on waterborne polyurethane acrylate/g-C3N4 co-crosslinked network for wood materials

Wood materials are often damaged due to exposure to environmental factors including humidity changes, temperature fluctuations, and ultraviolet radiation, resulting in surface aging, deformation, and cracking. Therefore, developing a new wood coating with good mechanical properties and weather resistance is conducive to improving the usability and service life of wood as an outdoor material. In this study, graphitic carbon nitride (g-C3N4) with a characteristic crystal structure was synthesized using melamine as raw material. By constructing a g-C3N4 /polyurethane acrylate co-crosslinked network, a UV-curable wood coating with excellent interfacial adhesion was prepared, which retained the natural aesthetic texture of the wood and imparted good wear resistance, anti-wetting property, and aging resistance to the wood material. Subsequently, the formation process and cross-linking reaction mechanism of the coating were revealed by XRD, FTIR and XPS measurements. Compared with untreated samples, coatings with a cross-linked network structure exhibited enhanced resistance to external environmental changes. As the content of the g-C3N4 increased (>1.0 %), the mechanical properties were significantly improved, with the mass loss rate and damaged area decreasing by 56.9 % and 60.0 %. Meanwhile, with the increased cross-link density of the coating, the water and heat resistance of the wood increased by 22.77 % and 260 %, respectively. After a seven-day UV aging resistance test, the ΔE values only changed by 10.28 %, showing good weathering resistance. This design and synthesis of wood coating provides an effective technology for the long-term use of outdoor wood material.

Multi-Parameter Prediction of Solar Greenhouse Environment Based on Multi-Source Data Fusion and Deep Learning

In the process of agricultural production in solar greenhouses, the key to the healthy growth of greenhouse crops lies in accurately predicting environmental conditions. However, there are complex couplings and nonlinear relationships among greenhouse environmental parameters. This study independently developed a greenhouse environmental acquisition system to achieve a comprehensive method for the monitoring of the greenhouse environment. Additionally, it proposed a multi-parameter and multi-node environmental prediction model for solar greenhouses based on the Golden Jackal Optimization-Convolutional Neural Network-Bidirectional Gated Recurrent Unit-Self-Attention Mechanism (GCBS). The GCBS model successfully captures the complex nonlinear relationships in the greenhouse environment and accurately predicts changes in carbon dioxide concentration, air temperature and humidity, and soil temperature at different location nodes. To validate the performance of this model, we employed multiple evaluation metrics and conducted a comparative analysis with four baseline models. The results indicate that, while the GCBS model exhibits slightly higher computational time compared to the traditional Long Short-Term Memory (LSTM) network for time series prediction, it significantly outperforms the LSTM in terms of prediction accuracy for four key parameters, achieving improvements of 76.89%, 69.37%, 59.83%, and 56.72%, respectively, as measured by the Mean Absolute Error (MAE) metric.

Research on friction and wear properties of new energy micro logistics vans brake materials under different ambient temperature and humidity conditions

This study explores the friction and wear performance of brake materials for new energy micro logistics vans under different ambient temperature (3 °C, 23 °C, 43 °C) and humidity conditions (35 %, 65 %, 95 %) using pin-disc experimental device. The findings reveal that at 3 °C, the friction coefficient exhibits extreme sensitivity to changes in humidity, with a significant reduction as humidity increases. Simultaneously, the increase of humidity leads to the transition from adhesive wear to abrasive wear and fatigue wear. At room temperature (23 °C) and 43 °C, humidity has minimal impact on the friction coefficient; however, higher humidity promotes oxidation film formation on the friction surface leading to dominant oxidation wear. Notably, in low-humidity environments, temperatures at 3 °C and 43 °C cause severe brake pad wear. The severity is greater at 43 °C because the resin-based components within the brake pad material decompose at elevated temperatures. Under such circumstances, appropriately increased humidity helps mitigate brake pad wear rates. However, too much humidity can increase fatigue wear of brake pad materials.

Carrageenan-modified MXene nanocomposite-based all-printed flexible humidity sensor for healthcare application

Transition metal carbides and carbonitrides (MXene) have emerged as promising nanomaterials for humidity-sensitive applications due to their abundant hydrophilic active sites and chemically reactive surfaces. However, designing MXene-based flexible humidity sensors with rapid response rates, high sensitivity, and structural stability remains a formidable challenge. Herein, we propose an all-printed humidity sensor fabricated on a paper-based substrate with copper electrodes and carrageenan-modified MXene composite materials. The all-printed humidity sensor prepared in this work exhibited outstanding potential in humidity sensing, showcasing high sensitivity (2073.5 %) and rapid response/recovery times (4.6/5.8 s). Meanwhile, the humidity sensor exhibits outstanding structural stability (with capacitance fluctuation maintained within 8.5 % after 500 bending cycles) and remarkable cyclic stability. Based on its excellent sensing performance and stability, the CAMX-2 sensor can effectively monitor skin humidity, fingertip contact levels, and humidity changes during various exercise modes. Therefore, this work offers a viable strategy for achieving reliable humidity monitoring, showcasing significant potential in the fields of sensing devices and healthcare.

Humidity Diffusion Process Analysis and Life Prediction of a VSC-HVDC Control Protection Device Based on a Finite Element Simulation Method

Voltage Source Converter-based High-Voltage Direct Current Transmission (VSC-HVDC) is essential for integrating renewable energy sources and facilitating inter-regional power transmission. This study evaluates the reliability of control and protection devices within these systems, which are crucial for the stable operation of power grids. Humidity significantly affects both the operational conditions and lifespan of these devices. Previous studies, reliant on extensive full-condition fatigue testing, have lacked effective test models and detailed analyses of mechanisms. To address this gap, a humidity diffusion model was developed to comprehensively investigate moisture diffusion mechanisms. Using the insights gained, the Hallberg–Peck model was applied to predict the lifespan of these devices, quantitatively assessing how changes in humidity affect their reliability. This approach employs a stringent failure criterion, leading to a conservative predicted lifespan. This method achieved a prediction accuracy of 85.648% compared to the benchmarks in GB/T 2423.50-2012, validating the accuracy of our model and the effectiveness of our simulation technology under stringent conditions. This research provides vital theoretical data and serves as an essential tool for guiding the precise maintenance of equipment in varying environmental humidity levels.

Concrete Gas Permeability: Implications for Hydrogen Storage Applications

Concrete is widely utilized across various industries as a containment material. One essential property related to its performance is permeability, which determines its ability to allow the passage of gases or liquids through its pores and capillaries and even the transmission of aggressive agents. This study focused on investigating the permeability of gases with varying atomic weights and molecular volumes, such as helium, nitrogen, oxygen, and argon, to pass through concrete. The primary objective was to determine the significance of variation in permeability and to evaluate and differentiate their behavior. To achieve this, concrete test specimens were employed, and factors such as cold joint impact, gas pressure, and specimen saturation levels were considered. Throughout the study, changes in weight, specimen humidity, resistivity, and ultrasonic pulse velocity were monitored. The findings suggested that within concrete, the variation in permeability for these gases is negligible. By utilizing the acquired data, the present study estimated the permeability of hydrogen through mathematical models based on gas pressure and concrete thickness. These insights contribute to a deeper comprehension of concrete gas permeability and its potential impact on improving hydrogen containment.

Machine learning-based analysis and prediction of meteorological factors and urban heatstroke diseases.

Heatstroke is a serious clinical condition caused by exposure to high temperature and high humidity environment, which leads to a rapid increase of the core temperature of the body to more than 40°C, accompanied by skin burning, consciousness disorders and other organ system damage. This study aims to analyze the effect of meteorological factors on the incidence of heatstroke using machine learning, and to construct a heatstroke forecasting model to provide reference for heatstroke prevention. The data of heatstroke incidence and meteorological factors in a city in South China from May to September 2014-2019 were analyzed in this study. The lagged effect of meteorological factors on heatstroke incidence was analyzed based on the distributed lag non-linear model, and the prediction model was constructed by using regression decision tree, random forest, gradient boosting trees, linear SVRs, LSTMs, and ARIMA algorithm. The cumulative lagged effect found that heat index, dew-point temperature, daily maximum temperature and relative humidity had the greatest influence on heatstroke. When the heat index, dew-point temperature, and daily maximum temperature exceeded certain thresholds, the risk of heatstroke was significantly increased on the same day and within the following 5 days. The lagged effect of relative humidity on the occurrence of heatstroke was different with the change of relative humidity, and both excessively high and low environmental humidity levels exhibited a longer lagged effect on the occurrence of heatstroke. With regard to the prediction model, random forest model had the best performance of 5.28 on RMSE and dropped to 3.77 after being adjusted. The incidence of heatstroke in this city is significantly correlated with heat index, heatwave, dew-point temperature, air temperature and zhongfu, among which the heat index and dew-point temperature have a significant lagged effect on heatstroke incidence. Relevant departments need to closely monitor the data of the correlated factors, and adopt heat prevention measures before the temperature peaks, calling on citizens to reduce outdoor activities.

Prevalence of Allergen-Specific Immunoglobulin E in 57558 Patients in 2012-2022

The study aims to preliminarily investigate the prevalence characteristics of allergen-specific immunoglobulin E (IgE) in 57558 patients over the past decade by examining its distribution in the province and exploring its associations with age, sex, temperature, and relative humidity, providing insights for the prevention and diagnosis of allergic diseases in the Sichuan region. A retrospective analysis was conducted on a cohort of 57558 patients who underwent allergen testing (by means of EUROIMMUN immunoblotting method) at West China Hospital, Sichuan University between August 2012 and February 2022. The clinical data of these patients were collected to establish a comprehensive database, while the temperature and humidity records of the corresponding timeframe were gathered for further analysis. The positive results from the allergen tests were categorized into four levels, including weakly positive (±), positive (+), moderately positive (++), and strongly positive (+++). Statistical analyses were performed using SPSS 25.0, with Chi-square tests conducted to compare count data and Pearson's correlation tests done conducted to assess the relationships between different types of allergens and temperature/relative humidity. P<0.05 was applied to determine statistically significant differences. GraphPad Prism 9.0.0 was utilized to generate visual representations of the data. The overall positivity rate of allergen-specific IgE among the 57558 samples was 30.69%. The top five allergens that elicited positive results were dust mite mix 1 (14.46%), crab (6.67%), soybean (4.72%), fish mix 1 (4.64%), and cockroach (4.34%). Notably, weakly positive (±) results were predominant for allergens such as eggs, peanuts, soybeans, cow's milk, beef, mutton, crab, shrimp, fish mix 1, cockroach, humulus japonicus, ambrosia artemisifolia, artemisia vulgaris, tree mix 2, house dust, and mold mix 1, collectively constituting over 40% of the positive outcomes. In contrast, cat hair and dog dander exhibited an equal distribution of approximately 25% for each positive levels, while mite mix 1 demonstrated the highest proportion of strongly positive results (+++), accounting for 37.66% of all positive results. Sex disparities in positivity rates were evident for various allergens, with significant differences observed for peanut, soybean, crab, shrimp, fish mix 1, cockroach, ambrosia artemisifolia, tree mix 2, cat hair, dog dander, and mite mix 1. Furthermore, the study identified age-related trends in allergen positivity rates, with a general decline observed across most allergens with increasing age. The positive rate of at least one food allergen was highest in the 0-10 age group (36.18%), and the positive rate of at least one inhalation allergen was highest in the 11-20 age group (45.35%). Noteworthy correlations were observed between allergen-specific IgE positivity and environmental factors, including a strong negative correlation between cow's milk allergy and relative humidity ( r=-0.640, P<0.05), a strong negative correlation of artemisia vulgaris sensitivity with temperature ( r Mean high temperature=-0.695, r Mean low temperature=-0.692, P<0.05), and a very strong positive correlation of mold mix 1 sensitivity with relative humidity ( r=0.704, P<0.05). Allergen-specific IgE positivity is associated with genetic factors, demonstrates significant sex- and age-related characteristics in the population, and is influenced by changes in local temperature and relative humidity.

A novel air curtain: Multi-parallel ejector air curtain for blood plasma cold storage

The installation of air curtains above the cold storage doors can reduce energy consumption. However, with the advancement of the refrigeration industry, the functions of cold storage have become more diversified and intelligent, rendering conventional fan-driven air curtains inadequate to meet market demands. Previous studies on air curtains primarily focused on their operational parameters and structures, neglecting the compatibility and applicability of air curtains with the functions of cold storage, thus lacking comprehensive experimental evaluation methods for their suitability. This study proposes a novel multi-parallel ejector air curtain suitable for automated plasma cold storage equipped with automatic doors. The performance of the air curtain is obtained through a comparison with conventional fan-driven air curtains in terms of sealing efficiency, temperature change and humidity change. Experimental results demonstrate that when the discharge velocity is 14 m/s, the multi-parallel ejector air curtain achieves a sealing efficiency of 39.6 %, resulting in a decrease of 0.92 ℃ in the average temperature rise within the cold storage and a reduction of 5.98 % in relative humidity increase. The sealing efficiency of conventional air curtains is 11.38 %, leading to a decrease of 0.82 °C in the average temperature rise within the cold storage and a reduction of 3.08 % in relative humidity increase. Analysis indicates that for automated plasma cold storage, the multi-parallel ejector air curtain is more applicable than conventional air curtains. At discharge velocity of 21 m/s and 26 m/s, the sealing efficiencies of the multi-parallel ejector air curtain are 54.47 % and 56.43 %, respectively, suggesting that moderately increasing the discharge velocity of air curtains contributes to enhancing their performance.

Changes in the Typhoon Intensity under a Warming Climate: A Numerical Study of Typhoon Mangkhut

Abstract Accurately assessing cyclone intensity changes due to global warming is crucial for predicting and mitigating sequential hazards. This study develops a high-resolution, fully coupled air–sea model to investigate the impact of global warming on Supertyphoon Mangkhut (2018). A numerical sensitivity analysis is conducted using the pseudo–global warming (PGW) technique based on multiple global climate models (GCMs) from phase 6 of Coupled Model Intercomparison Project (CMIP6). Under ocean warming scenarios, the increasing average sea surface temperature (SST) by 2.26°, 2.44°, 3.45°, and 4.53°C results in reductions in the minimum sea level pressure by 9.2, 10.6, 15.7, and 19.4 hPa, respectively, compared to the original state of Typhoon Mangkhut. Rising SST increases the turbulent heat flux; to be specific, an average SST increase of 2.26°–4.53°C changes the turbulent heat flux into 177%–272% of the original value. Besides, stronger winds enhance SST cooling, including upwelling and entrainment, leading to an increase in the mixed layer depth (MLD). Tropical cyclone heat potential (TCHP) tends to be enhanced under the combined influences as the SST rises. An average increase in the SST of 2.26°, 2.44°, 3.45°, and 4.53°C leads to an increase in the TCHP of 9.94%, 9.85%, 14.67%, and 15.30%, respectively. However, future changes in atmospheric temperature and humidity will moderate typhoon intensification induced by ocean warming. Considering atmospheric conditions, the maximum wind speed decreases by approximately 10% compared to only considering ocean warming. Nevertheless, typhoon intensity is projected to strengthen under future climate change. Significance Statement This study examines the role of global warming in typhoon intensity and the response of typhoon events to changes in the oceanic thermal structure. Sensitivity experiments considering future warming climates are conducted using a fully coupled air–sea numerical model. An average increase in sea surface temperature (SST) by 4.53°C can lead to a reduction in the minimum sea level pressure by 19.4 hPa. Ocean warming enhances oceanic mixing, potentially increasing the availability of heat energy for typhoon’s development (i.e., an average increase in SST by 4.53°C leads to a 15.30% increase in heat energy). However, future changes in atmospheric temperature and humidity will moderate the intensification of typhoons induced by ocean warming. These results are expected to provide information for assessing the future changes in typhoon intensity under a warming climate, which is important for predicting and reducing sequential risks.

Decomposing the effective radiative forcing of anthropogenic aerosols based on CMIP6 Earth system models

Abstract. Anthropogenic aerosols play a major role in the Earth–atmosphere system by influencing the Earth's radiative budget and precipitation and consequently the climate. The perturbation induced by changes in anthropogenic aerosols on the Earth's energy balance is quantified in terms of the effective radiative forcing (ERF). In this work, the present-day shortwave (SW), longwave (LW), and total (i.e., SW plus LW) ERF of anthropogenic aerosols is quantified using two different sets of experiments with prescribed sea surface temperatures (SSTs) from Earth system models (ESMs) participating in the Coupled Model Intercomparison Project Phase 6 (CMIP6): (a) time-slice pre-industrial perturbation simulations with fixed SSTs (piClim) and (b) transient historical simulations with time-evolving SSTs (histSST) over the historical period (1850–2014). ERF is decomposed into three components for both piClim and histSST experiments: (a) ERFARI, representing aerosol–radiation interactions; (b) ERFACI, accounting for aerosol–cloud interactions (including the semi-direct effect); and (c) ERFALB, which is due to temperature, humidity, and surface albedo changes caused by anthropogenic aerosols. We present spatial patterns at the top-of-atmosphere (TOA) and global weighted field means along with inter-model variability (1 standard deviation) for all SW, LW, and total ERF components (ERFARI, ERFACI, and ERFALB) and for every experiment used in this study. Moreover, the inter-model agreement and the robustness of our results are assessed using a comprehensive method as utilized in the IPCC Sixth Assessment Report. Based on piClim experiments, the total present-day (2014) ERF from anthropogenic aerosol and precursor emissions is estimated to be −1.11 ± 0.26 W m−2, mostly due to the large contribution of ERFACI to the global mean and to the inter-model variability. Based on the histSST experiments for the present-day period (1995–2014), similar results are derived, with a global mean total aerosol ERF of −1.28 ± 0.37 W m−2 and dominating contributions from ERFACI. The spatial patterns for total ERF and its components are similar in both the piClim and histSST experiments. Furthermore, implementing a novel approach to determine geographically the driving factor of ERF, we show that ERFACI dominates over the largest part of the Earth and that ERFALB dominates mainly over the poles, while ERFARI dominates over certain reflective surfaces. Analysis of the inter-model variability in total aerosol ERF shows that SW ERFACI is the main source of uncertainty predominantly over land regions with significant changes in aerosol optical depth (AOD), with eastern Asia contributing mostly to the inter-model spread of both ERFARI and ERFACI. The global spatial patterns of total ERF and its components from individual aerosol species, such as sulfates, organic carbon (OC), and black carbon (BC), are also calculated based on piClim experiments. The total ERF caused by sulfates (piClim-SO2) is estimated at −1.11 ± 0.31 W m−2, and the OC ERF (piClim-OC) is −0.35 ± 0.21 W m−2, while the ERF due to BC (piClim-BC) is 0.19 ± 0.18 W m−2. For sulfates and OC perturbation experiments, ERFACI dominates over the globe, whereas for BC perturbation experiments ERFARI dominates over land in the Northern Hemisphere and especially in the Arctic. Generally, sulfates dominate ERF spatial patterns, exerting a strongly negative ERF especially over industrialized regions of the Northern Hemisphere (NH), such as North America, Europe, and eastern and southern Asia. Our analysis of the temporal evolution of ERF over the historical period (1850–2014) reveals that ERFACI clearly dominates over ERFARI and ERFALB for driving the total ERF temporal evolution. Moreover, since the mid-1980s, total ERF has become less negative over eastern North America and western and central Europe, while over eastern and southern Asia there is a steady increase in ERF magnitude towards more negative values until 2014.

One-dimensional dynamic model of a PEM fuel cell for analyzing through-plane species distribution and irreversible losses under various operating conditions

This study develops a one-dimensional dynamic model of a proton-exchange membrane fuel cell (PEMFC), using species mole fractions as shared variables to examine through-plane water and oxygen distribution. During dynamic operation, the species mole fraction difference between the cathode channel/cathode gas distribution media (cCH/cGDM) interface and the cGDM/cathode catalyst layer (cGDM/cCL) interface varies with current density. When relative humidity (RH) changes from 20 % to 90 % at 1 A/cm2, the water mole fraction difference between cCH/cGDM and cGDM/cCL increases by 33.21 %, while the oxygen mole fraction difference increases by only 3.29 %. Current density step changes cause overshoot and undershoot behavior in the water mole fraction, affecting membrane water content, especially at low RH, where it remains low and sensitive to current and temperature changes. Beyond 50 % RH, membrane water content stabilizes, with fluctuations mainly observed on the anode side. The impact of species distribution on irreversible losses was then examined.Furthermore, oxygen transport resistance increases with operating pressure, while oxygen molecular diffusion remains stable. Conversely, rising temperatures substantially improve oxygen molecular diffusion. An analysis of FC loss profiles under various temperatures (333.15K–363.15K) and RH (0%–100 %) at constant loads (0.2&1 A/cm2) shows the model's capability in determining optimized operating conditions for PEMFCs.

Effects of cyclic ageing frequencies on the ageing and mechanical behaviour of adhesive materials: Experimental analysis and numerical study

In marine structures adhesive joint structures are often exposed to cyclic conditioning where the ambient humidity changes cyclically during their service. Though some comprehensive studies on the aging of adhesives exist, these researches mainly focus on monotonic aging conditions where the adhesive joints are exposed to a wet condition continuously for a long time. However, the few investigations performed on the cyclic moisture absorption of adhesive materials show that the parameters obtained in monotonic aging conditions are not suitable for estimation of the aging behaviour of adhesive exposed to alternating humidity. An important question that can arise is whether or not this frequency affects the mechanical behaviour of adhesive joints under cyclic aging condition. In this investigation bulk dogbone and square samples were manufactured, subjected to cyclic aging conditions with four different aging frequencies and tested. The results show that the moisture diffusion constant of adhesives exposed to higher aging frequencies increase more than those exposed to lower aging frequency conditions. In addition, the moisture content only affects the degradation of strength and stiffness of the tested adhesives in different aging frequencies.