Effect Of Humidity Research Articles

The Effect of Humidity and Dopants on the Detection of TNT Vapor by Differential Ion Mobility Spectrometry (DMS)

The Effect of Humidity and Dopants on the Detection of TNT Vapor by Differential Ion Mobility Spectrometry (DMS)

Studies on Lygus pratensis' (Hemiptera: Miridae) Flight Ability.

Lygus pratensis (Linnaeus) is an important agricultural pest with a strong ability to move and spread between hosts. However, L. pratensis' flight potential and factors affecting its flight ability are unclear. We used the insect flight information system (flight mill) to determine the effects of temperature, humidity, age, sex, and mating on L. pratensis' flight ability in an artificial climate chamber. Temperature and relative humidity significantly affected L. pratensis' flight ability; however, low and high temperature, as well as low humidity, were unsuitable, and the optimal flight environment was 20-28 °C and 60-75% RH. Lygus pratensis' flying ability initially increased and then decreased with age and was highest at 10 days old (flight rate: 71.43%; total flight distance: 18.63 ± 1.89 km; total flight time: 6.84 ± 0.60 h). At 15 days old, flight speed was the highest (3.36 ± 0.18 km h-1). Sex had little effect on L. pratensis' flying ability; it was marginally stronger for females than males, but the difference was insignificant. Mating increased female flying ability but decreased that of males, but the difference was insignificant. Overall, L. pratensis had strong flight dispersal ability, was largely unaffected by sex and mating, and optimal flight conditions were mild temperature and humidity. This knowledge provides a scientific basis for L. pratensis outbreak prediction, prevention, and control.

Numerical simulation and experimental study on the effect of cathode relative humidity on the performance of the PEMFC with dead-ended anode

ABSTRACT In the operation of the proton exchange membrane fuel cell (PEMFC) with dead-ended anode (DEA), the cathode relative humidity affects the accumulation state of water and nitrogen on the anode side, which in turn seriously affects the cell’s working performance. In order to investigate the mechanism of the cathode relative humidity on the PEMFC performance, numerical simulation and segmented in-situ measurement methods were used in this study. The results of the study showed that the lower cathode relative humidity causes insufficient water content in the PEMFC. This can further lead to localized dehydration of the membrane, which causes degradation of the DEA-PEMFC performance. Moreover, the higher cathode relative humidity increases the water content on the cathode side of the PEMFC. This not only increases the membrane permeability to nitrogen but also accelerates the water concentration back-diffusion process. The water and nitrogen that penetrate into the anode side can occupy the gas transport channel and hinder hydrogen transport, resulting in the insufficient localized gas supply in the DEA-PEMFC. This finally results in lower transient voltages and significantly shorter stabilized operation times. Therefore, reasonable control of cathode relative humidity is required to ensure long-term efficient and stable operation of the DEA-PEMFC.

Assessing the phenology and reproductive output of loggerhead turtles in relation to climatic variables at Patara Beach, Türkiye

AbstractLoggerhead turtles (Caretta caretta), being ectothermic organisms, could be especially susceptible to climate change effects, and may exhibit climate‐related variation in their reproductive behaviours such as phenology, annual nest numbers, clutch size, hatching success, incubation period and sex ratio. This study investigated the reproductive phenology and outputs of loggerhead turtles and their relationships with climatic variables over a 5‐year period (2019–2023) at Patara Beach, Türkiye. We found significant fluctuations in atmospheric temperature, sea surface temperature and relative humidity, and that female turtle emergences on Patara Beach could temporarily adjust their phenology in response to these minor environmental changes. We highlight the importance of understanding the impacts of phenological shifts on the ability to satisfy the conditions over the nesting season that determine reproductive output. Our statistical analyses also showed that increasing sea water temperatures and atmospheric temperatures, as well as decreasing precipitation and relative humidity, had direct and/or indirect effects on the nesting phenology and reproductive output of loggerhead turtles. The findings from this study indicate that atmospheric temperature significantly affected incubation period, hatching success rate, the number of dead embryos and the number of empty eggshells. Additionally, relative humidity had a significant impact on the incubation period and the number of empty eggshells. In this context, rising temperatures led to drier nest conditions, decreased incubation periods and increased nest temperatures, resulting in higher proportions of female offspring. In conclusion, there are still gaps in our understanding of the effects of climate change on the reproductive biology of loggerhead turtles, and more studies are needed at both the Mediterranean and global scales to better understand these effects.

Humidity Effects on Sub-Ambient Direct Air Capture of CO2 with Amine Functionalized Mg-Al LDHs and MMOs

Humidity Effects on Sub-Ambient Direct Air Capture of CO₂ with Amine Functionalized Mg-Al LDHs and MMOs

The Performance of PEFC with Marimo-like Carbon Considering Relative Humidity

A proton exchange membrane fuel cell (PEMFC) is powered by humidified fuel and air gases supplied to the cells. We evaluated the effect of the relative humidity (RH) of the fuel and air gases on the I-V performance of the Marimo-like carbon (MC). MC is a higher order structure of carbon fibers. The RH increased the proton conductivity of the Nafion, while excessive humidification caused flooding. The highest maximum power density was 303 mW cm-2 (80% RH) for the Pt/MC and 165 mW cm-2 (60% RH) for the Pt/CB (carbon black). At all the RHs, the maximum power density of the Pt/MC was higher than that of the Pt/CB. The fiber structure and I/C (0.1) of the MC increase the mass diffusivity of the Pt/MC. The high mass diffusivity of the Pt/MC found to reduce flooding and promote the wetting of the Nafion by the generated water.

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

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

Research on audible noise of ultra-high voltage direct current (UHV DC) transmission lines with a digital twin

Much attention has been paid to audible noise in the design of ultra-high voltage (UHV) direct current (DC) transmission lines because of its negative impact on residents' lives. In order to analyze audible noise, shorten the research period, and reduce experimental costs, firstly, a digital twin model for audible noise of UHV DC transmission lines is proposed. Then, the model’s structure and related principles are explained in detail. Finally, an application, as a research paradigm, uses digital twin to study the source distribution on transmission lines and influencing factors of audible noise. The A-weighted sound level of audible noise on the ground is calculated and compared with the data obtained by the BPA empirical formula. The results show that the position of the sound source tends to have uniform distribution and the intensity tends to have Gaussian distribution. We also used the model to simulate and analyze the effects of temperature and humidity on the generation and propagation of audible noise, illustrating the great value of digital twin technology in the study of audible noise. This paper not only provides a new method for audible noise research, but also provides a reference for the design of UHV DC transmission lines.

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

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

Effects of relative humidity on physiology and behavior of laying hens exposed to high ambient temperatures.

This study investigated how different relative humidity (RH) would impact behavior and physiology of laying hens. One hundred-eighty laying hens (Hy-Line Brown), aged 68-week-old (1,908 ± 78g), were exposed to daily ambient temperatures of 30°C with RH set at 25% (RH25), 50% (RH50), or 75% (RH75) for 12h a day (9:00 am to 9:00 pm) from 70 to 74 weeks of age. All hens had been raised at 24°C and 50% RH during 2-week adaptation period. Each RH treatment consisted of 10 replicates with 6 hens each in a completely randomized design. Results indicated that rectal temperature, respiratory rate, and heart rate were increased (P ≤ 0.05) in the RH75 group compared with the RH25 and RH50 groups. Plasma malondialdehyde concentrations were elevated in the RH75 group compared RH50 at 3, 7, and 21 days (P ≤ 0.05) following the RH exposure. Plasma glutathione peroxidase activity was lowered (P ≤ 0.05) in the RH75 group compared with the RH25 and RH50 groups at 21 days. Increasing RH led to decreased feeding behavior but showed a tendency to increase drinking behavior. Wings elevated and panting behaviors were higher in the RH75 group compared with the RH25 and RH50 groups (P ≤ 0.05). In conclusion, these findings suggest that elevated RH at constant ambient temperature could negatively influence the behavior and physiology of laying hens.

Effect of Temperature, Relative Humidity, and Incubation Time on the Mycotoxin Production by Fusarium spp. Responsible for Dry Rot in Potato Tubers.

Potato is the fourth most consumed crop in the world. More than half of the crop is stored for three to nine months at cold temperatures (3-10 °C) for the fresh and seed market. One of the main causes of fresh potato waste in the retail supply chain is the processing of fungal and bacterial rots during storage. Dry rot is a fungal disease that mainly affects the potato crop during storage and is responsible for 1% of tuber losses in the UK. It is produced by Fusarium spp., such as Fusarium sambucinum and F. oxysporum, which can lead to the accumulation of mycotoxins in the potato tuber. Little is known about the impact of environmental factors on the accumulation of mycotoxins in potato tubers. Understanding the ecophysiology of these fungi is key to mitigating their occurrence under commercial storage conditions. Therefore, this work aimed to elucidate the effect of three different temperatures (5, 10, and 15 °C) and two different water activities (aw; 0.97, 0.99) on the ecophysiology and mycotoxin accumulation of F. sambucinum and F. oxysporum in a potato-based semi-synthetic medium. The mycotoxin accumulation was then studied in vivo, in potato tubers cultivated under organic farming conditions, stored for 40 days at 8.5 °C. Results showed that higher temperatures and aw enhanced fungal growth, lag time, and mycotoxin accumulation in vitro. Growth rate was 2 and 3.6 times higher when the temperature increased from 5 to 10 and 15 °C, respectively. Six different mycotoxins (T-2, HT-2, diacetoxyscirpenol, 15-acetoxyscirpenol, neosolaniol, and beauvericin) were detected in vitro and in vivo. T-2 was the most abundant mycotoxin detected in vitro, observing 106 ng of T-2/g media after 21 days of incubation at 10 °C and 0.99 aw. Due to the long period of time that potato tubers spend in storage, the fluctuations of environmental factors, such as temperature and relative humidity, could promote the development of fungal rot, as well as mycotoxin accumulation. This could result in important food and economic losses for the potato market and a threat to food safety.

Effect of Humidity on Formaldehyde Oxidation over Ce0.8Zr0.2Oy Catalyst

Effect of Humidity on Formaldehyde Oxidation over Ce0.8Zr0.2Oy Catalyst

Measurement report: Occurrence of aminiums in PM2.5 during winter in China – aminium outbreak during polluted episodes and potential constraints

Abstract. Amines and aminiums play an important role in particle formation, liquid-phase reactions, and climate change and have attracted considerable attention over the years. Here, we investigated the concentrations and compositions of aminiums in PM2.5 in 11 Chinese cities during the winter, focusing on the characteristics of aminiums during the polluted days and the key factors influencing aminium outbreak. Monomethylaminium was the dominant aminium species in most cities, except Taiyuan and Guangzhou, followed by dimethylaminium. Diethylaminium dominated the total aminiums in Taiyuan and Guangzhou. Thus, the main amine sources in Taiyuan and Guangzhou were significantly different from those in other cities. The concentrations of the total aminiums (TAs) in most cities increased significantly during the polluted days, while relatively weak aminium outbreaks during the polluted days occurred in Xi'an and Beijing. Additionally, the concentrations of TAs in Xi'an and Beijing were insignificantly correlated with those of PM2.5 and the major acidic aerosol components, while the opposite pattern was observed in nine other cities. Thus, acid–base chemistry was significantly associated with the formation of aminiums in PM2.5 in all cities, except Xi'an and Beijing. Based on the sensitivity analysis of the aminiums : ammonium ratio to ammonium changes, as well as excluding the effects of relative humidity and atmospheric oxidation, we proposed the possibility of the competitive uptake of ammonia versus amines on acidic aerosols or the displacement of aminiums by ammonia in Xi'an and Beijing (constraining aminium outbreaks). Overall, this study deepens the understanding of the spatiotemporal differences in aminium characteristic and formation in China. However, the uptake of amines on particles to form aminiums and the relevant influencing factors require further mechanistic research.

NUMERICAL MODELLING OF RADIATOR SYSTEM PERFORMANCE UNDER BAUCHI CLIMATIC CONDITIONS

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

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

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

Changes in Spatiotemporal Pattern and Its Driving Factors of Suburban Forest Defoliating Pest Disasters

Forest defoliating pests are significant global forest disturbance agents, posing substantial threats to forest ecosystems. However, previous studies have lacked systematic analyses of the continuous spatiotemporal distribution characteristics over a complete 3–5 year disaster cycle based on remote sensing data. This study focuses on the Dendrolimus superans outbreak in the Changbai Mountain region of northeastern China. Utilizing leaf area index (LAI) data derived from Sentinel-2A satellite images, we analyze the extent and dynamic changes of forest defoliation. We comprehensively examine the spatiotemporal patterns of forest defoliating pest disasters and their development trends across different forest types. Using the geographical detector method, we quantify the main influencing factors and their interactions, revealing the differential impacts of various factors during different growth stages of the pests. The results show that in the early stage of the Dendrolimus superans outbreak, the affected area is extensive but with mild severity, with newly affected areas being 23 times larger than during non-outbreak periods. In the pre-hibernation stage, the affected areas are smaller but more severe, with a cumulative area reaching up to 8213 hectares. The spatial diffusion characteristics of the outbreak follow a sequential pattern across forest types: Larix olgensis, Pinus sylvestris var. mongolica, Picea koraiensis, and Pinus koraiensis. The most significant influencing factor during the pest development phase was the relative humidity of the year preceding the outbreak, with a q-value of 0.27. During the mitigation phase, summer precipitation was the most influential factor, with a q-value of 0.12. The combined effect of humidity and the low temperatures of 2020 had the most significant impact on both the development and mitigation stages of the outbreak. This study’s methodology achieves a high-precision quantitative inversion of long-term disaster spatial characteristics, providing new perspectives and tools for real-time monitoring and differentiated control of forest pest infestations.

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

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

The Effect of Relative Humidity in Conductive Atomic Force Microscopy.

Conductive atomic force microscopy (CAFM) analyzes electronic phenomena in materials and devices with nanoscale lateral resolution, and it is widely used by companies, research institutions, and universities. Most data published in the field of CAFM is collected in air at a relative humidity (RH) of 30-60%. However, the effect of RH in CAFM remains unclear becauseprevious studies often made contradictory claims, plus the number of samples and locations tested is scarce. Moreover, previous studies on this topic didnot apply current limitations, which can degrade the CAFM tips and generate false data. This article systematically analyzes the effect of RH in CAFM by applying ramped voltage stresses at over 17,000 locations on ten different samples (insulating, semiconducting, and conducting) under seven different RH. An ultra-reliable setup with a 110-pA current limitation during electrical stresses is employed, andexcellent CAFM tip integrity after thousands of tests is demonstrated. It is found that higher RH results in increased currents due to the presence of a conductivewater meniscus at the tip/sample junction, which increases the effective area forelectron flow. This trend is observed in insulators and ultra-thin semiconductors; however, in thicker semiconductors the electron mean free path is high enough to mask this effect. Metallic samples show no dependence on RH. This study clarifies the effect of relative humidity in CAFM, enhances understanding of the technique, and teaches researchers how to improve the reliability of their studies in this field.

The neurocognitive mechanism linking temperature and humidity with miners' working memory: an fNIRS study.

In China's coal mines, employees work in environments reaching depths of 650 m, with temperatures around 40°C and humidity levels as high as 90%, adversely affecting their health, safety capabilities, and cognitive functions, especially working memory. This study aims to explore different temperature and humidity conditions' impact on neurocognitive mechanisms to enhance occupational health and safety. This study, conducted between June and August 2023, with 100 coalmine workers from the Hongliulin Mining Group, utilized functional near infrared spectroscopy (fNIRS) and short-term visual memory tasks to evaluate the effects of high temperatures and humidity on working memory by monitoring activity in the cerebral cortex. Behavioral data, and neurophysiological data were analyzed using Tukey's HSD for significant differences and multiple regression to explore the impact of temperature and humidity. The β-values of Oxy-Hb for different regions of interest were calculated using General liner model (GLM), and the activation maps were plotted by NIRS_KIT. High temperature and humidity (Condition IV) significantly depressed reaction times and working memory compared to other conditions, with temperature having a more pronounced impact than humidity on these cognitive measures (p < 0.05). Oxy-Hb concentration increased notably under Condition IV, emphasizing temperature's influence on brain oxygen levels. ROI analysis revealed varied brain activation patterns. The activation of ROI A and B (prefrontal cortex) increased with the increase of temperature and humidity, while ROI C (supplementary motor area) was less sensitive to temperature, indicating the complex influence of environmental factors on brain function. This study highlights the important effects of temperature and humidity on cognitive performance and brain function, highlighting the need to optimize the environment of miners' sites to improve productivity and safety.

Edge-affected droplet dynamic and subsequent frost growth characteristics for horizontal cold plate under different humidity levels

Frosting widely exists in engineering applications and mostly has negative impacts. To better avoid or utilize frosting, more micro and systematic investigations into the frosting mechanisms are necessary. In this study, the combined effect of humidity and plate edge on droplet dynamic and the subsequent frost growth characteristics of a horizontal cold plate is experimentally investigated. The results show that the difference in the durations of droplet condensation stage between edge-affected and unaffected regions is little, and both decrease from around 480 to 43 s when relative humidity (RH) increases from 30% to 80%. In contrast, the difference in the durations of droplet freezing stage between edge-affected and unaffected regions is significant. The former is around 9 s at all humidity levels, while the latter decreases from around 100 s to 40 s when RH increases from 30% to 80%. Meanwhile, the average equivalent droplet diameters in the edge-affected region are 87.3 × 10−3–122.1 × 10−3 mm, which are 31.0 × 10−3–45.5 × 10−3 mm larger than in the unaffected region. The frost layer surface roughness at 80% RH is smaller than others due to the frost crystal reverse melting. This paper can help better understand the frosting mechanism from a microscopic scale and guide the accurate prediction of frost formation.