Low Relative Humidity Conditions Research Articles

Characteristics of new particle formation events occurred over the Yellow Sea in Springtime from 2019 to 2022

Characteristics of atmospheric new particle formation (NPF) events were investigated using the data obtained from the ship measurement campaign named Yellow Sea Air Quality (YES-AQ) over the Yellow Sea during the springtime from 2019 to 2022. NPF events occurred 15 times for the valid 128 observation days for the four-year period, and the average and standard deviation formation rate (FR) and growth rate (GR) of the NPF events were 2.38 ± 1.53 cm−3 s−1 and 4.11 ± 2.81 nm h−1, respectively. The FR and GR were close to those in urban regions, implying the unique characteristics of the Yellow Sea. Owing to the NPF events, the number concentrations of total aerosols and nucleation mode particles increased by approximately 7850 and 6002 cm−3, respectively, and those of cloud condensation nuclei at 0.2% and 0.6% supersaturation increased by about 1269 and 3269 cm−3, respectively. The NPF events mostly occurred under the meteorological conditions of low temperature and relative humidity as well as high solar radiation and wind speed. These meteorological conditions appeared predominantly when the air mass originated from the continent north of the Korean Peninsula. The current analyses based on the data measured repeatedly during a specific period each year, which were not well conducted in other maritime NPF studies, highlight the reliability of the presented characteristics of NPF events over the Yellow Sea.

Aerosol influence on cloud macrophysical and microphysical properties over the Tibetan Plateau and its adjacent regions.

This study uses aerosol optical depth (AOD) and cloud properties data to investigate the influence of aerosol on the cloud properties over the Tibetan Plateau and its adjacent regions. The study regions are divided as the western part of the Tibetan Plateau (WTP), the Indo-Gangetic Plain (IGP), and the Sichuan Basin (SCB). All three regions show significant cloud effects under low aerosol loading conditions. In WTP, under low aerosol loading conditions, the effective radius of liquid cloud particles (LREF) decreases with the increase of aerosol loading, while the effective radius of ice cloud particles (IREF) and cloud top height (CTH) increase during the cold season. Increased aerosol loading might inhibit the development of warm rain processes, transporting more cloud droplets above the freezing level and promoting ice cloud development. During the warm season, under low aerosol loading conditions, both the cloud microphysical (LREF and IREF) and macrophysical (cloud top height and cloud fraction) properties increase with the increase of aerosol loading, likely due to higher dust aerosol concentration in this region. In IGP, both LREF and IREF increase with the increase in aerosol loading during the cold season. In SCB, LREF increases with the increase in aerosol loading, while IREF decreases, possibly due to the higher hygroscopic aerosol concentration in the SCB during the cold season. Meteorological conditions also modulate the aerosol-cloud interaction. Under different convective available potential energy (CAPE) and relative humidity (RH) conditions, the influence of aerosol on clouds varies in the three regions. Under low CAPE and RH conditions, the relationship between LREF and aerosol in both the cold and warm seasons is opposite in the WTP: LREF decreases with the increase of aerosol in the cold season, while it increases in the warm season. This discrepancy may be attributed to a difference in the moisture condition between the cold and warm seasons in this region. In general, the influence of aerosols on cloud properties in TP and its adjacent regions is characterized by significant nonlinearity and spatial variability, which is likely related to the differences in aerosol types and meteorological conditions between different regions.

VARIATIONS OF δ18О AND δ2H VALUES OF PRECIPITATION IN MOSCOW FROM 2017 TO 2019

To reveal variations in the iso topic composition of O and H in the atmospheric precipitation in Moscow and the processes influencing the isotope composition, all events of precipitation in 2017-2019 were sampled at the Meteorological Observatory of the Moscow State University: 158 samples in 2017, 119 samples in 2018 and 143 samples in 2019. The study is a prolongation of continuous measurements of the isotope composition of precipitation, started by authors in 2014. The study of the isotope composition of precipitation at the MSU Meteorological Observatory was supported by the IAEA and became a part of the Global Network of Isotopes in Precipitation (GNIP) database. It has been found that the intra-annual variability of the isotop e composition of precipitation has a pronounced seasonality. The most isotopically heavy precipitation falls from May to August, and the most isotop ically light precipitation at December-February, mainly due to seasonal air temperature variations. The ratio of the average monthly δ18O values in precipitation and air temperature for the study period varied from 0.34 to 0.39‰/°C, which is consistent with the previously obtained data for precipitation in Moscow. The δ2H-δ18O ratio in precipitation was clos e to that of the Global Meteoric Water Line, pointing to the equilibrium conditions during precipitation formation. It was established that in the summer months isotopic composition is significantly influenced by undercloud evaporation. The deuterium excess va lues in precipitation are not markedly seasonal; however, lower dexc values (below the 3-year average of 11‰) are typical for the summer months (July-August). It is most likely due to undercloud evaporation in conditions of low relative humidity and high air temperatures. Higher dexc values (above 11‰) prevailed from October to April.

A highly sensitive flexible humidity sensor based on a wafer-level composite material of carbon-quantum-dots@nanofiber clusters

A novel composite material composed of carbon-quantum-dots@nanofiber clusters (CQDs@NFCs) is successfully developed in wafer level, taking it as a sensitive material, a flexible humidity sensor is also developed. Since the composite material is superhydrophilic and contains a super large number of nanopores of different sizes, capillary condensation is able to take place within the composite material at different relative humidity (RH) conditions. Taking advantage of the chemi-physisorption and the capillary condensation, such a sensing material helps to significantly improve sensitivity of the flexible sensor, especially at low RH conditions. Compared with the device adopting only nanofibers as the sensing material, this novel sensor offers a 4.3-time increament in sensitivity within a humidity range of 7%−59% RH, while maintains high sensitivity in the entire humidity range. This heightened sensitivity is crucial for monitoring low-level humidity with high accuracy, making the sensor highly promising for various applications.

Prediction model of asphalt emulsion evaporation rate based on CFD simulation and genetic programming-based symbolic regression

The evaporation rate of asphalt emulsion is critical to the strength development of asphalt emulsion materials. Its value is dependent on environmental factors, i.e. relative humidity, temperature, and wind speed. However, the quantitative relation of evaporation rate with these environmental factors are unclear. To quantificationally study the effect of environmental factors on the water evaporation rate of asphalt emulsion, a computational fluid dynamics (CFD) simulation model of water evaporation is firstly proposed and validated by experiment. Then, wide range of environmental factors are studied in the CFD simulation model, and genetic programming-based symbolic regression is used to train the simulation results of CFD samples. Finally, a relatively accurate prediction equation of the evaporation rate of asphalt emulsion versus environmental factor is proposed, and the sensitivity of the water evaporation rate under the three environmental factors is analyzed. Results show that the evaporation rate can be accurately simulated by CFD. All the three environmental factors can greatly affect the evaporation rate of asphalt emulsion, while their effect on the sensitivity of the water evaporation rate is ranked as: temperature > relative humidity > wind speed. To ensure an acceptable curing period, asphalt emulsion-based materials should be avoided to be paved in the conditions of low temperature and high relative humidity.

Photo-oxidative Crack Propagation in Transition Metal Dichalcogenides.

Monolayered transition-metal dichalcogenides (TMDs) are easily exposed to air, and their crystal quality can often be degraded via oxidation, leading to poor electronic and optical device performance. The degradation becomes more severe in the presence of defects, grain boundaries, and residues. Here, we report crack propagation in pristine TMD monolayers grown by chemical vapor deposition under ambient conditions and light illumination. Under a high relative humidity (RH) of ∼60% and white light illumination, the cracks appear randomly. Photo-oxidative cracks gradually propagated along the grain boundaries of the TMD monolayers. In contrast, under low RH conditions of ∼2%, cracks were scarcely observed. Crack propagation is predominantly attributed to the accumulation of water underneath the TMD monolayers, which is preferentially absorbed by hygroscopic alkali metal-based precursor residues. Crack propagation is further accelerated by the cyclic process of photo-oxidation in a basic medium, leading to localized tensile strain. We also found that such crack propagation is prevented after the removal of alkali metals via the transfer of the sample to other substrates.

Reaction between Criegee Intermediate CH2OO and Isobutyraldehyde: Kinetics and Atmospheric Implications

AbstractIn the present work, we have investigated the 1,3‐cycloaddition reaction of isobutyraldehyde ((CH3)2CHCHO) with the simplest Criegee intermediate CH2OO using the OH laser‐induced fluorescence (LIF) method in a reaction tube. The experiments were conducted at temperatures and pressures ranging from 280 to 338 K and 5 to 150 Torr. We found that the bimolecular rate coefficient of the reaction is temperature‐ and pressure‐dependent. The measured rate coefficients at 100 Torr are (4.93±0.89), (4.46±0.80), (3.99±0.72), (3.56±0.64), (3.34±0.60), (2.98±0.54), (2.78±0.50)×10−12 cm3 molecule−1 s−1 at 280, 288, 298, 308, 318, 328, and 338 K, respectively. A high‐pressure limit rate coefficient of (4.47±0.80)×10−12 cm3 molecule−1 s−1 was obtained at 298 K by fitting the pressure‐dependent rate coefficients according to the Lindemann mechanism. The Arrhenius plot of the temperature‐dependent rate coefficients results in an activation energy of (−1.86±0.33) kcal mol−1 and a preexponential factor of (1.72±0.31)×10−13 cm3 molecule−1 s−1. In the atmosphere, the reaction of CH2OO with isobutyraldehyde may contribute to the sink of CH2OO in regions where isobutyraldehyde emission is intense under low temperature and low relative humidity conditions.

Bunch transpiration is involved in the hastening of grape berry ripening under elevated temperature and low relative humidity conditions

The present study aimed: i) to evaluate the impact of the changes in temperature and relative humidity (RH), projected by the year 2100, on grape ripening, and ii) to assess if bunch transpiration is a key physiological process involved in the advancement in grape development under future climate conditions. Fruit-bearing cuttings of Vitis vinifera L. cv. ‘Tempranillo’ were grown, from fruit set to maturity, in glasshouses under two conditions: 24°C/14°C and 55%/70% RH (day/night) (T) vs 28°C/18°C and 43%/58% RH (T+4). To elucidate the role of bunch transpiration in grape development in a future climate scenario, the bunches of half of the plants in the T+4 glasshouse were sprayed with an antitranspirant (AT+4). T+4 increased bunch transpiration, hastened the ripening process, increasing the rate of total soluble solid (TSS) accumulation and malic acid degradation, and reduced the concentration of total anthocyanins. The application of antitranspirant partially alleviated the effects of combined high temperature and low RH on maturation times, through lower TSS accumulation rates. Berries in AT+4 had the lowest concentrations of anthocyanins and color, likely related to a reduction in light transmittance by the antitranspirant film and to higher anthocyanin degradation due to the longer exposure to elevated temperatures. The results show a negative impact of elevated temperature and low RH on grape composition. The increased bunch transpiration under these conditions played an important role in the changes observed in phenology and sugar accumulation.

Performance analysis of a rotary desiccant wheel using polymer material with high water uptake and low regeneration temperature

Desiccant wheels have been widely used in humidity control, particularly under conditions with ultra-low dew point temperatures. However, traditional desiccants such as silica gel and zeolites are subject to relatively low adsorption capacity and high regeneration temperature. To address these challenges, a type of polymer material with high water uptake and low regeneration temperature is investigated in this paper. Firstly, the adsorption/desorption capacity of this polymer is thoroughly tested. Results reveal that its remarkable equilibrium adsorption capacity and desorption rate coefficients kLDF,de are 350% and 32–64% higher than that of silica gel, respectively. Moreover, its required regeneration temperature is just about 40–70 °C. The performance of the desiccant wheel using this polymer is simulated by a model validated by experiments tests. Parameter analysis demonstrates that the desiccant wheel is suitable for cool and humid conditions, reaching the maximum moisture removal (∆Y) and dehumidification coefficient of performance (DCOP) of 4.0 g kg−1 and 0.66, respectively. Furthermore, the corresponding relationship between other parameters and the optimal rotation speed is discussed in detail. The ωopt is around 18 rph, enabling the attainment of the highest ∆Y. Finally, the performance comparison with a traditional silica gel desiccant wheel is carried out. The results indicate that the polymer one performs 17–53.9% higher in terms of both ∆Y and DCOP than the silica gel counterpart. And the most significant improvement is observed in low relative humidity conditions (45%RH), where ∆Y and DCOP are 1.25–1.53 times that of the silica gel's, highlighting the advantageous utilization of the polymer material.

Standardized agronomic practices for mechanical harvesting of the single-harvest garden pea in India

The field investigations were conducted at Vegetable Research Farm, Department of vegetable Science, Punjab Agricultural University, Ludhiana with the objective to standarize the agronomic practices for mechical harvesting of garden pea. Therefore, effect of different agronomic traits including time of sowing, spacing and sowing method on yield and its attributing traits were studied on single-harvest garden pea. The experiment was laid out in split-plot design with 30 treatments comprising five dates of sowing in main plots and 2 different planting methods (flat and bed) sown at three different spacing in subplots and replicated three times. The bed size was standardized according to front-loading width of the pea combine. Significant interactions were observed between the date of sowing and spacing for a number of pods per plant, green seeds per pod, green pod yield per plant, green pod yield per plot; date of sowing and sowing method for pod length; spacing and sowing method for plant height. However, for all the traits, there was non-significant 3-way interaction. The late sown (20th December) crop resulted in the least number of pods per plant, green seeds per pod, green pod yield per plant and green pod yield per plot which was due to high temperature and low relative humidity conditions at pod development and filling stage. It is concluded that the garden pea cultivar Punjab-89 sown on 5th November at the spacing of 20 × 7.5 cm on beds (bed width of 1.0 m) resulted in significantly highest green pod yield of 12.75 kg/9 m2 in the single harvest. Therefore, the 3 beds of 1 m width can be harvested together with pea combine (because combine has working front width of 3.1 m) results into maximum yield when pea crops is sown on 5th November @ 20 × 7.5 cm spacing.

Microcracking of strawberry fruit cuticles: mechanism and factors

Microscopic cracks in the cuticle (microcracks) are the first symptom of the strawberry fruit disorder ‘water soaking’ in which the fruit surface appears watery, translucent, and pale. Water soaking severely impacts fruit quality. The objective was to investigate the factors and mechanisms of cuticular microcracking in strawberry. Fluorescence microscopy revealed numerous microcracks in the achene depressions, on the rims between depressions and at the bases of trichomes. Microcracks in the achene depressions and on the rims were either parallel or transversely oriented relative to a radius drawn from the rim to the point of attachment of the achene. In the achene depression, the frequency of microcracks with parallel orientation decreased from the calyx end of the fruit, towards the fruit tip, while the frequency of those with transverse orientation remained constant. Most microcracks occurred above the periclinal cell walls of the epidermal cells. The long axes of the epidermal cells were primarily parallel-oriented. Microcracking increased during fruit development. Cuticle mass per fruit remained constant as fruit surface area increased but cuticle thickness decreased. When fruit developed under high relative humidity (RH) conditions, the cuticle had more microcracks than under low RH conditions. Exposing the fruit surface to increasing RHs, increased microcracking, especially above 75% RH. Liquid-phase water on the fruit surface was markedly more effective in inducing microcracking than high vapor-phase water (high RH). The results demonstrate that a combination of surface area growth strain and water exposure is causal in inducing microcracking of the strawberry cuticle.

Significant impact of water-soluble organic matter on hygroscopicity of fine particles under low relative humidity condition

Uncertainties in estimating the hygroscopicity of bulk aerosols under conditions of low relative humidity (RH) or below the deliquescent RH (DRH) of aerosols remain to be significant, mainly due to the presence of water-soluble organic matter (WSOM). To quantify the contributions of WSOM to aerosol hygroscopicity and associated uncertainties, a field campaign was conducted to measure the hygroscopic growth curve (f(RH)) of bulk aerosols online, dominant chemical compositions in PM2.5 online and offline, and size distributions of the dominant chemical compositions offline during the dry and wet seasons of 2019–2020 in urban Guangzhou of south China. Based on the measured f(RH), the hygroscopicity parameter (κ) of bulk aerosols (κ-f(RH)) exhibits a logarithmic increase with increasing RH until RH reaches 69 %. Beyond this threshold, κ-f(RH) increases very slowly with further increase of RH, reaching 0.32 ± 0.04 during the dry season and 0.31 ± 0.05 during the wet season. The κ of WSOM (κ-WSOM) was further estimated to be 0.22 ± 0.03 and 0.13 ± 0.04 in the dry and wet seasons, respectively, when RH > 69 %. WSOM significantly affects κ-f(RH) by retarding the deliquescence process of aerosols and altering the mass ratio of water-soluble inorganic salts (WSIS) to WSOM within the size range of 0.4–0.9 μm, especially under low RH conditions (<60 %). The κ-f(RH) under low RH conditions was revised based on the logarithmic regression equation between RH and the ratio of measured κ-f(RH) to estimated κ-f(RH>69%). f(RH) of WSIS and WSOM were then corrected using the revised κ-f(RH) under low RH conditions, which showed 22–31 % lower values than those produced by the IMPROVE formulas.

High-performance and durable membrane electrode assemblies based on CeO2 and ePTFE double-reinforcement strategy for proton exchange membrane fuel cells operating at elevated temperatures

The membrane electrode assemblies (MEAs) play a decisive role in operating conditions and lifetime of fuel cell. In this study, MEAs that could work stably at elevated temperatures were prepared. With this method, a short-side chain perfluorosulfonic acid ionomer coating with CeO2 nanoparticles and two layers of expanded polytetrafluoroethylene reinforcement, to be used as a proton exchange membrane, was directly deposited between the cathode and anode gas diffusion electrodes, forming a double-reinforced integrated MEA. The effects of CeO2 doping amount on performance and other electrochemical properties of MEAs were systematically studied. Under the coupling effect of the water-retention and non-proton-conducting properties of CeO2, the 0.5 wt% CeO2-doped MEA (MEA-S0.5) had optimal performance above 100 °C and under low relative humidity (RH) conditions. At 120 °C and 30% RH, MEA-S0.5 exhibited peak power density of 0.460 W cm−2 (H2/air operation, 100 kPa), which was about 1.28 times that of MEA without CeO2 doping (MEA-S0). Furthermore, CeO2 effectively enhanced the durability of the MEA. Compared with MEA-S0, MEA-S0.5 did not exhibit significant degradation in output power, H2 crossover, or proton conductivity in the 100-h open-circuit voltage-holding test. This work paves the way for developing high-performance, durable MEAs that are suitable for elevated temperatures.

Relative humidity-dependent evolution of molecular composition of α-pinene secondary organic aerosol upon heterogeneous oxidation by hydroxyl radicals

Heterogeneous oxidation by gas-phase oxidants is an important chemical transformation pathway of secondary organic aerosol (SOA) and plays an important role in controlling the abundance, properties, as well as climate and health impacts of aerosols. However, our knowledge on this heterogeneous chemistry remains inadequate. In this study, the heterogeneous oxidation of α-pinene ozonolysis SOA by hydroxyl (OH) radicals was investigated under both low and high relative humidity (RH) conditions, with an emphasis on the evolution of molecular composition of SOA and its RH dependence. It is found that the heterogeneous oxidation of SOA at an OH exposure level equivalent to 12 hr of atmospheric aging leads to particle mass loss of 60% at 25% RH and 95% at 90% RH. The heterogeneous oxidation strongly changes the molecular composition of SOA. The dimer-to-monomer signal ratios increase dramatically with rising OH exposure, in particular under high RH conditions, suggesting that aerosol water stimulates the reaction of monomers with OH radicals more than that of dimers. In addition, the typical SOA tracer compounds such as pinic acid, pinonic acid, hydroxy pinonic acid and dimer esters (e.g., C17H26O8 and C19H28O7) have lifetimes of several hours against heterogeneous OH oxidation under typical atmospheric conditions, which highlights the need for the consideration of their heterogeneous loss in the estimation of monoterpene SOA concentrations using tracer-based methods. Our study sheds lights on the heterogeneous oxidation chemistry of monoterpene SOA and would help to understand their evolution and impacts in the atmosphere.

Effects of ambient temperature and humidity on viruses activity on different architectural coatings and kinetics study

The inactivation rates of non-encapsulated virus (MS2, φA039, enterovirus EV71) and enveloped virus (influenza A virus H3N2) on architectural coating with different porosity were measured at different temperatures and relative humidity (RH). To study the variation of virus activity on different architectural coating with temperature and humidity and provide reference for the control of indoor building surface virus. The inactivation rate of the virus on different surfaces was analyzed at 15 °C, 25 °C, 35 °C and 45 °C and at RHs of 30 %, 60 %, and 90 % for 12 h or 24 h. Overall, the architectural porous coating is adsorbent to viruses. Under low temperatures and high RH conditions (15 °C, 90 % RH), the viruses can survive longer on the surface of the architectural nonporous (few pores) coating. At low humidity, water can evaporate rapidly on the porous surface, which contributes to virus inactivation, especially for nonenveloped viruses. Architectural porous coating can absorb and retain more water, which reduces the impact of high temperature on the virus under high humidity conditions. The inactivation rate of H3N2 on porous surfaces decreased with the decrease of humidity. In addition, the first-order kinetic and nonlinear Weibull models are used to describe the virus inactivation data. The inactivation of the virus on the surface of the architectural coating and the goodness of fit of the virus inactivation rate is related to the porosity of the architectural coating, temperature, RH, and the type of virus.

Experimental investigation of operating characteristics of proton exchange membrane fuel cell with different anode strategies based on the segmented cell

ABSTRACT In this study, we investigated the operating characteristics of large-scale proton exchange membrane (PEM) fuel cells under different anode strategies, including flow-through mode, dead-ended mode, and recirculation mode, under typical automotive conditions using the segmented fuel cell. The experimental parameters such as output performance, current density distribution, anode pressure, and high-frequency resistance (HFR) of the PEM fuel cells are measured by several experimental approaches, and the three anode strategies are evaluated by analyzing their H2 utilization, output performance stability, and system efficiency. The results show that the flow-through mode presents the most stable performance but the lowest H2 utilization of 71.5%. Under the dead-ended mode, the performance degradation caused by the accumulation of water and N2 can be recovered by purge, but that caused by membrane dehydration cannot be well recovered. Moreover, a self-humidification effect of the recirculation mode is observed in the experiments, which helped to improve the system efficiency of the PEM fuel cell under low relative humidity conditions to 35.23%, significantly higher than that of 26.51% under the flow-through mode and 29.92% under the dead-ended mode. Therefore, the recirculation mode is more conducive to the commercialization of PEM fuel cells than the other two anode strategies.

Perfluorosulfonic acid proton exchange membrane with double proton site side chain for high-performance fuel cells at low humidity

Structural optimization of ionomers is an effective strategy for achieving high-performance proton exchange membranes (PEMs) under low relative humidity (RH) conditions. In this study, sulfonimide group and trifluoromethanesulfonate acid (TFSA) ionic liquids were introduced to the perfluorosulfonic acid (PFSA) side chain, resulting in polymer membranes with varying chain lengths (i.e., PFC2-TF-SI, PFC4-TF-SI, and PFC5-TF-SI). This dual proton-conducting structure extended the length of the hydrophilic side chain and enhanced the hydrophobic-hydrophilic phase separation, aiding in the formation of proton transport channels. Notably, the proton conductivity of PFC5-TF-SI and PFC2-TF-SI membranes reached 7.1 and 10.6 mS/cm at 30% RH and 80 °C, respectively, which were approximately 29.1% and 92.7% higher than that of the pristine PFC5-SA membrane (5.5 mS/cm). Furthermore, the maximum power density of the PFC5-TF-SI and PFC2-TF-SI membranes from the built single fuel cell achieved 649 and 763 mW/cm2 at 30% RH and 80 °C, respectively, which were higher than that of the pristine PFC5-SA membrane (567 mW/cm2) by about 14.5% and 34.6%, respectively. Thus, this study provides a strategy for PEM design under low RH conditions.

Atmospheric humidity regulates same-sex mating in Candida albicans through the trehalose and osmotic signaling pathways.

Sexual reproduction is prevalent in eukaryotic organisms and plays a critical role in the evolution of new traits and in the generation of genetic diversity. Environmental factors often have a direct impact on the occurrence and frequency of sexual reproduction in fungi. The regulatory effects of atmospheric relative humidity (RH) on sexual reproduction and pathogenesis in plant fungal pathogens and in soil fungi have been extensively investigated. However, the knowledge of how RH regulates the lifecycles of human fungal pathogens is limited. In this study, we report that low atmospheric RH promotes the development of mating projections and same-sex (homothallic) mating in the human fungal pathogen Candida albicans. Low RH causes water loss in C. albicans cells, which results in osmotic stress and the generation of intracellular reactive oxygen species (ROS) and trehalose. The water transporting aquaporin Aqy1, and the G-protein coupled receptor Gpr1 function as cell surface sensors of changes in atmospheric humidity. Perturbation of the trehalose metabolic pathway by inactivating trehalose synthase or trehalase promotes same-sex mating in C. albicans by increasing osmotic or ROS stresses, respectively. Intracellular trehalose and ROS signal the Hog1-osmotic and Hsf1-Hsp90 signaling pathways to regulate the mating response. We, therefore, propose that the cell surface sensors Aqy1 and Gpr1, intracellular trehalose and ROS, and the Hog1-osmotic and Hsf1-Hsp90 signaling pathways function coordinately to regulate sexual mating in response to low atmospheric RH conditions in C. albicans.

Analysis of annual citizen odor observation records and its relationship with meteorological factors: Çorlu / Tekirdağ case study

Odor pollution is a primary environmental problem and the most frequent public complaint. The emission levels of air pollutants, the distance of emission sources from residential areas, and topography and other geographical and meteorological conditions influence the level and intensity of air and odor pollution. Owing to the lack of standard management approaches, citizen survey studies supported by geographic information systems have become critical in collecting odor observation data in the immission site. In this study, FIDOL (frequency, intensity, duration, odor tone, and location) factor-based annual odor observation data were collected, using the Çorlu KODER mobile application. Statistical analysis determined whether meteorological factors affected the average daily number of odor observations (NOOs) throughout the year. Temperature was the meteorological factor with the most significant effect on the increase in average daily NOOs. Furthermore, it was determined whether the Hybrid Single-Particle Lagrangian Integrated Trajectory model estimated the mixed layer height (MLH) and relative humidity (RH) parameters that significantly affected the average daily NOOs during August 2021–October 2021. This period was considered critical because over 80% of the annual NOOs occurred within this timeframe. MLH, RH, and MLH–RH significantly affected the average daily NOOs. Analysis using the Sturges classification revealed that odor observations were mainly intensified under low RH and MLH conditions. I In addition, the frequency of odor episodes increased under low MLH conditions. Seven consecutive odor episodes between August and October 2021 were further analyzed, considering the spatial and temporal distribution of odor observations, MLH and RH values, and back-trajectory findings. Analysis based on the air pollutant transport mechanism suggested that almost all of the odor episodes experienced in Çorlu within the study period were related to emissions from the organized industrial zone (OIZ) regions. The findings suggest that emissions from the OIZs located in the north-east and north of Çorlu have a more intense effect on odor observations in Çorlu residential areas.

Equilibrium moisture content in charcoal exposed to different relative humidity conditions

Equilibrium moisture content is an important characteristic associated with hydrocarbon fuels, including biomass and charcoal. Its determination is essential since it negatively affects several properties, especially the caloric value and energy density. Thus, this research was conducted with the aim of determining the equilibrium moisture content of charcoal produced for industrial purposes from 6-year-old Eucalyptus and Corymbia species exposed to different relative humidity conditions at a temperature of 30°C. Four samples of charcoal were collected from each of the four species of Eucalyptus and Corymbia used in the study. The equilibrium moisture content of the samples was always achieved by desorption. At the end of the experiment, the dry masses were obtained. Twelve simple and multiple linear models were used to estimate the equilibrium moisture of the samples. Overall average equilibrium moisture estimates were slightly higher in Eucalyptus species in all relative humidity conditions, except at 90%. Considering the scientific principle of parsimony, the simple linear model was selected for both Corymbia and Eucalyptus species. The difference between Corymbia and Eucalyptus equilibrium moisture of charcoal was higher at lower relative humidity conditions.