Increasing Air Humidity Research Articles

The massive 2016 marine heatwave in the Southwest Pacific: An "El Niño-Madden-Julian Oscillation" compound event.

El Niño typically induces cooling in the Southwest Pacific Ocean during austral summers, usually leading to decreased marine heatwave frequency and severity. However, the 2016 extreme El Niño unexpectedly coincided with the longest and most extensive marine heatwave ever recorded in the region. This heatwave, spanning over 1.7 million square kilometers, persisting for 24 days with a peak intensity of 1.5°C, resulted in massive coral bleaching and fish mortality. This exceptional warming resulted from anomalously strong shortwave radiation and reduced heat loss via latent heat fluxes, owing to low wind speed and increased air humidity. These anomalies are attributed to a rare combined event "Madden-Julian Oscillation and extreme El Niño." Following 10 February, the rapid dissipation of this marine heatwave results from the most intense cyclone ever recorded in the South Pacific. The hazardous ecological impacts of this extreme event highlight the needs for improving our understanding of marine heatwave-driving mechanisms that may result in better seasonal predictions.

ВЛИЯНИЕ СОВРЕМЕННОГО ИЗМЕНЕНИЯ КЛИМАТА НА ИСПАРЕНИЕ С ВОДНОЙ ПОВЕРХНОСТИ В ИЛЕ-БАЛКАШСКОМ БАССЕЙНЕ

Using the Ile-Balkash basin as an example, changes in evaporation from the water surface over the last 40 years, as well as changes in the main meteorological elements that affect evaporation, are considered. Within the framework of this work, the changes in evaporation from the water surface for 1996-2020 in relation to the previous period of 1980-1995 were assessed. It was established that over the last 20 years, there was a slight increase in evaporation at many lowland stations of the Ile-Balkash basin and it is about 1-10 %. In mountainous areas and near large water areas, such as Balkash and Ulken Almaty Lakes, there is a decrease in evaporation by about 2-9 %. The main factors influencing the change in evaporation values from the water surface were analyzed. It was concluded that the increase in evaporation from the water surface at the lowland stations in the Ile-Balkash basin is mainly due to the increase in air temperature and some increase in precipitation, and the decrease in evaporation in mountainous areas and near a water area is caused by the decrease of average wind speed and an insignificant increase in air humidity. This study can help support decision making in the agriculture and water resources sector, since evaporation from the water surface is involved in many hydrological, climatic and hydrodynamic models. Therefore, the obtained results can be used in many scientific calculations.

Fine-scale monitoring of catkins reveals an association between catkin concentration and plant community characteristics and microclimate

Catkins, as a significant source of plant-caused pollution, disrupts daily human activities and industrial processes. Despite their impact, catkins have not been included in official environmental quality monitoring indicators, leading to a deficiency in scientifically rigorous collection and monitoring methodologies, as well as a lack of ecological prevention and management strategies. In this study, we introduced a fine-scale monitoring approach for catkins. Qualitative and quantitative relationships between catkin concentrations, plant community characteristics and microclimate factors were elucidated by analyzing on-site catkin concentration data from 33 representative plant communities in Beijing. Furthermore, we summarized the ecological strategies for the prevention and management of these catkins. The results indicated that (1) TS (three-dimensional green volume of trees in the catkin source layer), SB (three-dimensional green volume of shrubs in the catkin barrier layer), GB (three-dimensional green volume of ground cover plants in the catkin barrier layer), T (three-dimensional green volume of trees in the whole plant community), W (three-dimensional green volume of the whole plant community), species diversity, and relative air humidity were key plant community characteristics and microclimate factors influencing catkin concentration. Among these factors, TS, T, W, and relative air humidity showed a significant positive correlation with catkin concentration, while SB, GB, and species diversity exhibited a significant negative correlation with catkin concentration. (2) All seven key factors exhibited nonlinear relationships with catkin concentration. (3) TS served as the primary deciding factor for catkin concentration within the plant community. When TS > 744.0755 m3, the secondary decision factor for catkin concentration was GB. Otherwise, the determinants were SB and species diversity. The results showed that enhancing tree species diversity, enhancing the three-dimensional green volume of shrubs and ground cover plants, and increasing air humidity were practical means to facilitate the sedimentation of catkins. The measures used to obstruct catkins vary depending on the TS. When catkin source plants are abundant within a plant community, it is advisable to prioritize increasing ground cover plants. Conversely, when fewer sources of such plants exist, emphasis can be placed on augmenting mid-layer shrubs and diversifying plant species. These findings provide a scientific foundation for the planting design and stock optimization of communities containing catkin source plants.

Collision of Two Plasma Diffuse Jets with the Same and Different Front Polarity at an Air Pressure of 1 Torr

In air at a pressure of 1 Torr, the mode of collision of diffuse plasma jets (PDJs) consisting of ionization waves — red streamers have been studied. PDJ were formed in a quartz tube by a capacitive discharge from two identical generators with pulses of positive and negative polarity. It has been established that, with the same polarity of voltage pulses, counter-current PDJs suppress each other’s radiation. It is shown that for different polarity of voltage pulses, the intensity of the glow in the region where the PDJ meets increases significantly. Data are presented on the effect of delays between switching on generators of different polarity on the emission spectra of PDJ. It has been established that with an increase in air humidity, an atomic hydrogen line Ha appears in the emission spectrum, as well as OH and OH+ bands, the spectral energy density (W) of some of which is commensurate with the W bands of the second positive (2+) nitrogen system. The velocity of the PDJ front was measured when two generators of different polarity were turned on.

Adapting to climate change: responses of fine root traits and C exudation in five tree species with different light-use strategy.

Trees that are categorised by their light requirements have similarities in their growth strategies and adaptation mechanisms. We aimed to understand the complex responses of elevated air humidity on whole tree fine root carbon (C) exudation (ExC) and respiration rate, morphology, and functional distribution in species with different light requirements. Three light-demanding (LD) species, Populus × wettsteinii, Betula pendula, and Pinus sylvestris, and two shade-tolerant species, Picea abies and Tilia cordata saplings were grown in growth chambers under moderate and elevated air relative humidity (eRH) at two different inorganic nitrogen sources with constant air temperature and light availability. The proportion of assimilated carbon released by ExC, and respiration decreased at eRH; up to about 3 and 27%, respectively. There was an indication of a trade-off between fine root released C and biomass allocation. The elevated air humidity changed the tree biomass allocation and fine root morphology, and the responses were species-specific. The specific fine root area and absorptive root proportion were positively related to canopy net photosynthesis and leaf nitrogen concentration across tree species. The variation in ExC was explained by the trees' light-use strategy (p < 0.05), showing higher exudation rates in LD species. The LD species had a higher proportion of pioneer root tips, which related to the enhanced ExC. Our findings highlight the significant role of fine root functional distribution and morphological adaptation in determining rhizosphere C fluxes in changing environmental conditions such as the predicted increase of air humidity in higher latitudes.

Small oases below the canopy: The cooling effects of water-filled tree holes on the local microclimate in oak-dominated stands

The relevance of forests in mitigating biodiversity loss and the negative effects of climate change on the biota is largely shaped by below-canopy microclimatic conditions, which are buffered, cooler and more humid compared to adjoining open habitats. Water-filled tree holes (dendrotelms, DTs) are special tree-related microhabitats that host semi-aquatic communities and are important substrates or water sources for numerous taxa (e.g., birds, mammals, insects, fungi, bryophytes). Despite their microrefugia-role might be more pronounced under climate change-induced drought events, little is known about their microclimate and its potential drivers.In an abandoned Turkey oak-dominated coppice stand in Hungary, the microclimates of 80 paired dendrotelms and adjacent forest plots were measured in the summer of 2021. Compared to nearby open areas, under closed forests, air temperature maxima were up to 5 °C cooler, DTs had an additional negative offset of 2.5 °C and increased air humidity by 15 percentage points (5% vs. 20 %). The local microclimate of DTs and the adjacent closed forest differed significantly in means and extremes of air temperature, relative humidity and vapour pressure deficit, which was mainly driven by DT entrance area and water volume and seemed independent from local stand structure. On the contrary, nearby below-canopy microclimate was shaped by the distance from forest edge, incoming light and tree density. Water volume in DTs also influenced local forest microclimates up to 0.5–1 m from the entrances.As the frequency and severity of extreme weather events such as heatwaves are likely to intensify due to climate change, the importance of microhabitats and habitat trees for invertebrates and vertebrates will increase further, and will additionally contribute to the microclimatic refugia role of forests. Active protection of veteran trees under the scheme of continuous cover forestry or conservation-oriented management is essential facing climate change to mitigate its negative effects on forest biodiversity.

Reproductive Traits in Two Alpine Endemic Species of Campanulaceae

Alpine plants are well adapted to environments with extreme conditions – low temperatures, a short growing season, increased air humidity and precipitation, and are therefore of particular interest for research. The aim of the present study is to reveal the main reproductive characteristics of two endemic species of the family Campanulaceae, namely Campanula orbelica (Balkan endemic) and Jasione bulgarica (Bulgarian endemic). The main features of the reproductive biology (embryological features, type of reproduction) were established based on the study of micro- and macrosporogenesis and the development of male and female gametophytes. The established features of the reproductive structures and processes characterized C. orbelica and J. bulgarica as sexually reproducing species. Despite the extreme conditions of existence, the studied species presented normal generative progresses leading to the formation of pollen and embryo, which ensures their successful reproduction, populations stability and their distribution in the subalpine environment. In addition, the genome size of C. orbelica was studied by flow cytometry. The estimated genome size varied in the range 1C = 1.34–1.38 pg. No deviation in the ploidy level was found in 22 specimens fresh leaves of which were collected from different parts of the Rila and Pirin Mts.

Analisis Korelasi Kelembaban Udara terhadap Epidemi Demam Berdarah yang Terjadi di Kota Bengkulu

Dengue (Dengue Fever) is a vector bone disease caused by the Aedes Aegepty Mosquito. The aim of this research is to determine the relationship between air humidity levels and the Dengue Fever epidemic that occurred in Bengkulu Municipality. This research is a type of descriptive research with quantitative methods which aims to determine and show the relationship between air humidity levels and cases of Dengue Fever (DHF). This research was conducted in the Municipality of Bengkulu, using quantitative data on air humidity obtained from the Climatology Station (Meteorology, Climatology and Geophysics Agency) Baai Island, Bengkulu City, namely air humidity data from 2009 to 2014 and data on Dengue Fever cases in the Municipality obtained from the Department Bengkulu Province Health from 2009 to 2014 data. Judging from the results, the level of increase in air humidity in Bengkulu Municipality in 2009-2014 ranged from 82% - 86%. It can be seen that the number of dengue fever cases in Bengkulu Municipality in 2009-2014 was around 173 - 472 people. Data processing was carried out by computer using SPSS and Microsoft Excel programs. The results of the analysis using the bivariate test show that air humidity has a relationship between the incidence of Dengue Fever that occurs in the Municipality of Bengkulu, with a value of r=0.408 and p-value=0.007.

The influence of the probiotic “Bioseven” on indicators of survival and growth of calves in the early postnatal period

Dairy cattle breeding is one of the promising areas of agriculture. With a systematic approach and modern technologies, it is a highly profitable agrarian business that is dynamically developing. According to experts, the competitiveness and profitability of the industry can be increased due to the use of natural feed additives and preparations to obtain ecologically safe products for humans. Among them, preparations of microbiological origin are increasingly used, in particular, probiotics, which contain living microorganisms useful for the macroorganism. These drugs are used for prophylactic or therapeutic purposes. It is known that most microorganisms inhabiting the intestines are safe and do not cause diseases, but there is a constant competition between bacteria of different species for space and nutrients. The inconsistency of the microclimate parameters in the calf pens had a direct negative effect on the calf's body, especially in the early postnatal period. In particular, the deviation from the temperature balance, increased air humidity, and the presence of drafts caused a violation of the heat exchange processes of the calves' body with hypothermia and overheating of the body, and, as a result, provoked the frequent occurrence of respiratory diseases. In addition, increased air humidity and high microbial pollution caused the emergence of diseases with functional disorders in the digestive tract due to an imbalance of normal flora and increased activity of the development of transit microbes from the external environment, which negatively affected the homeostasis of the calves' body, weakened the natural resistance of calves, their growth, preservation and often led to the death of animals. Oral use of the probiotic “Bioseven” in a dose of 5.0 g (1.5·109 CFU/cm3) based on 10 kg of live weight ensured the complete preservation of the herd of young calves, accelerated their growth energy, as evidenced by exterior indicators of the animals of the experimental group against the control and probable (P &lt; 0.05) average daily gains in live weight – 1.236 ± 0.37 kg/day versus 1.002 ± 0.41 kg/day in the control group of calves. In further studies, we used a dose of the probiotic “Bioseven” – 5.0 g (1.5·109 CFU/cm3) based on 10 kg of live weight, as the optimal dose of the experimental drug, established by the results of research. Comparative results of studies of growth indicators in the calves of the experimental group showed a significant advantage in the actual probable (Р &lt; 0.01) increase in their live weight during the experimental period, which exceeded the similar indicators of the control by 23.6 %. The results of studies of indicators of average daily live weight gain were significantly (Р &lt; 0.05) higher than those of control calves by 28.5 % (Р &lt; 0.01), which testified to the effectiveness of the use of the probiotic “Bioseven” in young calves. Taking into account the obtained results, it becomes clear that the components of the probiotic drug “Bioseven” have a positive effect on the formation of cicatricial digestion in calves.

COLD LOGISTICS AS A COMPONENT OF TRANSPORT AND LOGISTICS SYSTEMS IN PORT CITIES

Abstract.Cold logistics in the modern world is gaining more and more relevance. The development of international trade and the globalization of the economy contribute to an increase in the volume of transportation of goods that require special storage and transportation conditions. Cold logistics originated in the pharmaceutical industry, now more and more goods require a special temperature regime - agricultural products, fish and meat products, etc. Also, in connection with the growing popularity of a healthy lifestyle and increasing awareness of the importance of proper nutrition, the demand for fresh vegetables and fruits is actively growing. This presents new tasks and requirements for the cold logistics system.Changes in temperature regimes, increased air humidity levels, and other factors can negatively impact the quality and safety of products during transportation. Therefore, addressing these issues requires the implementation of innovative technologies and logistics management strategies aimed at ensuring stability and safety of supplies.As a result of the conducted research, it was found that cold logistics represents an important field of logistics specializing in effectively maintaining temperature conditions during the storage and transportation of products. This sector plays a key role in ensuring the safety, quality, and freshness of food products, especially those prone to rapid spoilage.Recently, there has been a trend towards consolidation of cold supply chains. Understanding the essence of cold logistics and the peculiarities of the transportation organization in the cold chain are important aspects for ensuring the efficiency and reliability of logistics processes.This article examines theoretical approaches to defining the concept of "cold logistics", investigates the characteristic features of cold logistics, provides a characterization of "fresh" and "frozen" category goods, identifies factors stimulating and restraining the development of the cold logistics market, and explores the interaction of participants in cold supply chains in transport and logistics systems of port cities.Keywords: cold logistics, transport and logistics system, port cities, supply chain

Analysis of Characteristics in the Macro-Composition and Volatile Compounds of Understory Xiaobai White Tea.

Understory planting affects the growth environment of tea plants, regulating the tea plant growth and the formation of secondary metabolites, which in turn affects the flavor of Xiaobai white tea. The present research adopted biochemical composition determination, widely targeted volatilities (WTV) analysis, multivariate statistical analysis, and odor activity value (OAV) analysis to analyze the characteristics in the macro-composition and volatile compounds of understory white tea. The sensory evaluation results indicated that understory Xiaobai white tea (LWTs) was stronger than ordinary Xiaobai white tea (PWTs) in terms of the taste of smoothness, sweetness, and thickness as well as the aromas of the flower and sweet. Understory planting reduced light intensity and air temperature, increased air humidity, organic matter, total nitrogen, and available nitrogen contents, which improved the growth environment of tea plants. The phytochemical analysis showed that the water-extractable substances, caffeine, flavonoids, and soluble sugar contents of understory tea fresh-leaf (LF) were higher than those of ordinary fresh-leaf (PF). The phytochemical analysis showed that the free amino acids, theaflavins, thearubigins, water-extractable substances, and tea polyphenols contents of LWTs were significantly higher than those of PWTs, which may explain the higher smoothness, sweetness, and thickness scores of LWTs than those of PWTs. The 2-heptanol, 2-decane, damasone, and cedar alcohol contents were significantly higher in LWTs than in PWTs, which may result in stronger flowery and sweet aromas in LWTs than in PWTs. These results provide a firm experimental basis for the observed differences in the flavor of LWTs and PWTs.

Influence of Relative Humidity on Electrical Properties of Textile Laminates

The aim of this paper is to determine the influence of relative humidity on the comfort and electrical resistance properties of textile laminates in order to predict possible changes in footwear protection levels. Four textile laminates of different structure and fibre nature were selected for the study. It was determined that water vapour absorption of textile laminates strongly depends on the humidity of the storage environment. The absorption ability of laminates increases about 1.8 – 3 times as relative humidity increases from 65 % up to 95 %. The degree of increase depends on the textile laminate structure and the nature of the materials layers. The electrical properties of protective footwear can be influenced by the structure, thickness, relative humidity, and voltage of textile laminates. For textile laminates composed of natural and synthetic fibres and polymer foam as insulators, the resistivity increases with the thickness of the synthetic fibre and polymer layer. At low voltage (U = 100 V), the textile laminates tested became insulating materials, as the electrical resistivity exceeded the threshold values for antistatic materials in all relative humidity ranges. At high voltage (U = 500 V) the electrical resistivity of textile the laminates drops dramatically when the relative air humidity increases and the level of protection of the laminates depend on the amount of moisture absorbed and the nature of the layer materials. The laminates possessed insulating properties in environments of up to 65 % relative humidity. In a high humidity of the environment, the insulating properties of textile laminates turned to antistatic, except for laminate without a polymeric membrane, which became conductive.

On the influence of humidity on the breakdown strength of air—with a case study on the PDIV of contacting enameled wire pairs

The partial discharge inception voltage (PDIV) in contacting enameled wire pairs exhibits a marked decrease with increased air humidity. While existing literature mentions several potential mechanisms for this reduction, a comprehensive quantitative assessment of the associated effects is lacking. This research paper addresses this knowledge gap by providing a quantitative estimation of the combined impact of water on the gas’s ionization yield (effective ionization coefficient) and the modification of the gap electric field caused by water absorption into the bulk of the insulating coating and the associated microscopic and macroscopic polarization processes (dielectric permittivity). However, a comparison of the theoretical predictions with experimental data reveals that these factors alone cannot fully account for the observed reduction in PDIV. Therefore, the study explores additional mechanisms mentioned in the literature, with particular focus on the development of a semi-conductive layer on the insulation coating in humid atmospheres. The numerical simulations of the surface charge dynamics within this layer suggests that the frequency-dependent decrease in PDIV under high-humidity atmospheres can indeed be attributed to the modification of the gap electric field due to the accumulation of surface charge in the semi-conductive layer.

Transpiring, phytoncidal and gas-absorbing properties of indoor plants and their role in improving the air quality in preschool environments

BACKGROUND: The high incidence of respiratory diseases among children attending preschool educational institutions highlights the need for prevention of respiratory tract infections. With children spending on average up to 10 hours a day in educational settings, the quality of the indoor air environment, including microbial contamination and low relative humidity, poses a risk for respiratory diseases. Placing a selection of plants in organized groups of children can offer a promising and cost-effective approach to promote health and well-being in the modern preschool education system. AIM: To select indoor plants based on their species and quantity to improve the air quality in organized children’s groups. Moreover, the paper presents recommendations for the installation and maintenance of the plants to create healthier environment for children. MATERIALS AND METHODS: Among more than 820 species of indoor plants, we have identified the most suitable options for preschool institutions. The selection process involved measuring the dimensions of the plants and the surface area of their leaves using a metric method. To assess the air quality, we conducted air sampling throughout the working week, once per hour, using an aspiration method with a sampling device PU-1B. Simultaneously, we measured the microclimate parameters in all the rooms included in the study. Furthermore, we studied the gas absorption capacity of indoor plants in controlled laboratory conditions within seed chambers with a volume of 200 liters. RESULTS: In rooms where plants were present, the levels of microorganisms varied. The average relative humidity values in all rooms were consistently below the hygienic standard of 40–60%, as outlined in SanPiN 1.2.3685-21, except for specific times. At 8:00, 9:00, 10:00, and 18:00, the relative humidity ranged from 15–35%. When exposed to a formaldehyde concentration of 3 times the maximum permissible concentration (MPC) Chlorophytum comosum reduced it to the regulated value of 0.01 MPC within 38 hours while the corresponding values for Sansevieria trifasciata and Cyperus alternifolius were 24 and 27 hours, respectively. CONCLUSION: Introducing a variety of indoor plants into a preschool educational setting can have significant benefits for air quality. The plants possess phytoncidal, transpiring, and gas-absorbing properties that contribute to a reduction in the overall number of microorganisms, a decrease in chemical pollutants, and an increase in air humidity. Our analysis showed that in the presence of indoor plants, the concentration of formaldehyde decreases to a regulated and safe level.

Machine Learning in the Analysis of Carbon Dioxide Flow on a Site with Heterogeneous Vegetation

The article presents the results of studies of carbon dioxide flow in the territory of section No. 5 of the Eurasian Carbon Polygon (Russia, Republic of Bashkortostan). The gas analyzer Sniffer4D V2.0 (manufactured in Shenzhen, China) with an installed CO2 sensor, quadrocopter DJI MATRICE 300 RTK (manufactured in Shenzhen, China) were used as control devices. The studies were carried out on a clear autumn day in conditions of green vegetation and on a frosty November day with snow cover. Statistical characteristics of experimental data arrays are calculated. Studies of the influence of temperature, humidity of atmospheric air on the current value of CO2 have been carried out. Graphs of the distribution of carbon dioxide concentration in the atmospheric air of section No. 5 on autumn and winter days were obtained. It has been established that when building a model of CO2 in the air, the parameters of the process of deposition by green vegetation should be considered. It was found that in winter, an increase in air humidity contributes to a decrease in gas concentration. At an ambient temperature of 21 °C, an increase in humidity leads to an increase in the concentration of carbon dioxide.

Effect of Humidity on the Inactivation of Bacillus Subtilis Spore by Non-thermal Atmospheric Air Plasma

Objective: If a medical device is not properly disinfected, it will pose a potential danger to patients. Spore is an experimental strain to verify the effect of disinfection on medical devices. It has a complex structure and is somewhat resistant to conventional disinfection techniques. Based on the advantages of simple structure and abundant reactive oxygen and nitrogen species (RONS), surface dielectric barrier discharge (SDBD) has been used to deal with inactivate spores, which provided experimental support for the application of sterilization spores in medical devices. Methods: The sterilization efficiency of the plasma was evaluated by calculating the number of viable colonies on Tryptose Soya Agar. RONS including ozone, nitrogen oxides and other reactive species produced in SDBD were measured by ozone analyzer, Fourier infrared spectrometer and chemical probes, respectively. Ultraviolet-visible spectrophotometer was used to determine the concentration of protein and nucleic acid. Results: After 20min of SDBD treatment, the number of inactivated spores could reach more than 4 log at high humidity (&gt;6g/m3), while the spores were hardly inactivated at low humidity (&lt;6g/m3). Ozone production was inhibited with increasing humidity while OH radicals and peroxynitrous acid increased with increasing humidity. The optical density values of protein and nucleic acid released from spores treated with SDBD was detected and a strong correlation was found with the spore inactivation trend. The protein shell and membrane structure of the spores were destroyed by SDBD, and more leakage and destruction of proteins and nucleic acids in the spores were obtained under the high humidity. Conclusion: With the increase of air humidity (from 0.15g/m3 to 70.16g/m3), stable SDBD is obtained showing a typical filamentous discharge pattern. Compared with low humidity, high humidity is more favorable to SDBD inactivation of spores.

Modeling understory shrub diversity related to environmental gradients using Akaike Information Criterion (AIC) in an urban forest in Jakarta, Indonesia

Abstract. Kirana GR, Wibowo AA, Nurdin E, Wardhana W, Basukriadi A. 2023. Modeling understory shrub diversity related to environmental gradients using Akaike Information Criterion (AIC) in an urban forest in Jakarta, Indonesia. Asian J For 7: 74-80. The urban forest is one form of human-made ecosystem in urban environments. One of the most important components of urban forest ecosystem is understory shrubs. The sustainability of understory shrub community is supported by environmental variables suitable to its growth. Nonetheless, there has been limited information on how environmental variables contribute to the presence of shrubs in particular urban settings. This study aims to model the relationships between understory shrub diversity and environmental covariates, including air temperature, humidity, light intensity and wind speed, using the Akaike Information Criterion (AIC) in Srengseng Urban Forest, Jakarta, Indonesia. The result showed that there were 20 species and 12 families with the most common shrub species being Rivina humilis, followed by Acalypha siamensis, Cordyline fruticosa, Syzigium paniculatum and Caesalpinia pulcherrima. The average Shannon-Wiener diversity index was 0.671 (95% CI: 0.441, 0.901). The AIC models showed that understory shrub diversity was negatively correlated with humidity and positively correlated with light gradients with AIC values of 38.696 and 41.679, respectively. The diversity of understory shrubs in urban forests was significantly supported by sufficient light intensity (R2 = 0.29) and limited by an increase in air humidity (R2 = -0.44). The humidity and light intensity combinations also affect the understory shrub diversity (AIC = 38.900, R2 = 0.256). The results of these studies can help urban forest managers manage urban forests if aiming for biodiversity conservation, especially understory shrub species.

Humidity sensor element based on porous silicon – reduced graphene oxide sandwich-like structures

In this study, the field-effect transistor (FET) based on porous silicon (PS) – reduced graphene oxide (rGO) sandwich-like structure is suggested as a sensitive element of the humidity sensor. It is shown that the position of the charge neutrality point (Dirac point) and the ratio between the hole and electron branches of the resistance profile of the PS–rGO-based FET depend significantly on the relative humidity. An increase in air humidity causes a decrease in the electrical resistance and an increase in the capacity of the obtained FET. The sensing ability and dynamic characteristics were analyzed to estimate the sensory properties of the PS–rGO sandwich-like structure. A higher sensitivity of the resistive sensor element than the capacitive has been found. The response time of the obtained sensors to changing relative humidity is about 1 min at room temperature. As a result, the PS–rGO-based FET demonstrates high potential applications in humidity-sensitive devices.

Solid-Oxide Amperometric Sensor for Hydrogen Detection in Air

An amperometric sensor based on CaZr0.95Sc0.05O3−δ (CZS) proton-conducting oxide for the measurement of hydrogen concentration in air was designed and tested. Dense CZS ceramics were fabricated through uniaxial pressing the powder synthesized by the solid-state method and sintering at 1650 °C for 2 h. The conductivity of CZS was shown to increase with increasing air humidity, which indicates the proton type of conductivity. The sensor was made from two CZS plates, one of which had a cavity was drilled to form an inner chamber, that were then pressed against each other and sealed around the perimeter to prevent gas leaking. The inner chamber of the sensor was connected with the outer atmosphere via an alumina ceramic capillary, which acted as a diffusion barrier. The sensor performance was studied in the temperature range of 600–700 °C in the mixtures of air with hydrogen. The sensor signal, or the limiting current, was found to linearly increase with the hydrogen concentration, which simplifies the sensor calibration. The sensor demonstrated a high sensitivity of ~60 μA per 1% H2 at 700 °C, a fast response, high reproducibility, good selectivity, and long-term stability.

Influence of Humidity and Salinity on the Discharge Characteristics of a Short Rod-Plane Gap Under Negative DC Voltage

In this article, the effects of air humidity and salinity on the discharge characteristics of a short rod-plane gap under negative dc voltage are investigated experimentally. The discharge of the rod-plane gap was recorded using a measuring resistance, photomultiplier tube, and ultraviolet imager. The experimental results show that corona discharge of rod electrode can be observed in the rod-plane gap when the relative humidity is lower than 70%, and furthermore, partial discharge of water molecules in the air can also be observed in the rod-plane gap when the relative humidity is higher than 70%. The partial discharge inception voltage (PDIV) decreases with the increase of air humidity and salinity, and the corona discharge inception voltage (CDIV) increases slightly with the increase of humidity. The average discharge current increases with the increase of applied voltage and humidity. The repetition rate of the optical pulse and the Trichel pulse increases with the increase of applied voltage. The discharge repetition rate of water molecules in the air can be estimated from the repetition rate difference between the optical pulse and the Trichel pulse. The amplitude of the Trichel pulse in clean air is higher than that in the salty air, while the repetition rate of the Trichel pulse in clean air is lower than that in the salty air, which is due to the charging of NaCl particles during discharge.