RH Changes Research Articles

Design, Calibration and Morphological Characterization of a Flexible Sensor with Adjustable Chemical Sensitivity and Possible Applications to Sports Medicine.

Active life monitoring via chemosensitive sensors could hold promise for enhancing athlete monitoring, training optimization, and performance in athletes. The present work investigates a resistive flex sensor (RFS) in the guise of a chemical sensor. Its carbon 'texture' has shown to be sensitive to CO2, O2, and RH changes; moreover, different bending conditions can modulate its sensitivity and selectivity for these gases and vapors. A three-step feasibility study is presented including: design and fabrication of the electronic read-out and control; calibration of the sensors to CO2, O2 and RH; and a morphological study of the material when interacting with the gas and vapor molecules. The 0.1 mm-1 curvature performs best among the tested configurations. It shows a linear response curve for each gas, the ranges of concentrations are adequate, and the sensitivity is good for all gases. The curvature can be modulated during data acquisition to tailor the sensitivity and selectivity for a specific gas. In particular, good results have been obtained with a curvature of 0.1 mm-1. For O2 in the range of 20-70%, the sensor has a sensitivity of 0.7 mV/%. For CO2 in the range of 4-80%, the sensitivity is 3.7 mV/%, and for RH the sensitivity is 33 mV/%. Additionally, a working principle, based on observation via scanning electron microscopy, has been proposed to explain the chemical sensing potential of this sensor. Bending seems to enlarge the cracks present in the RFS coverage; this change accounts for the altered selectivity depending on the sensor's curvature. Further studies are needed to confirm result's reliability and the correctness of the interpretation.

SAW Humidity Sensing with rr-P3HT Polymer Films.

In the present paper the humidity sensing properties of regioregular rr-P3HT (poly-3-hexylthiophene) polymer films is investigated by means of surface acoustic wave (SAW) based sensors implemented on LiNbO3 (1280 Y-X) and ST-quartz piezoelectric substrates. The polymeric layers were deposited along the SAW propagation path by spray coating method and the layers thickness was measured by atomic force microscopy (AFM) technique. The response of the SAW devices to relative humidity (rh) changes in the range ~5-60% has been investigated by measuring the SAW phase and frequency changes induced by the (rh) absorption in the rr-P3HT layer. The SAW sensor implemented onto LiNbO3 showed improved performance as the thickness of the membrane increases (from 40 to 240 nm): for 240 nm thick polymeric membrane a phase shift of about -1.2 deg and -8.2 deg was measured for the fundamental (~78 MHz operating frequency) and 3rd (~234 MHz) harmonic wave at (rh) = 60%. A thick rr-P3HT film (~600 nm) was deposited onto the quartz-based SAW sensor: the sensor showed a linear frequency shift of ~-20.5 Hz per unit (rh) changes in the ~5-~50% rh range, and a quite fast response (~5 s) even at low humidity level (~5% rh). The LiNbO3 and quartz-based sensors response was assessed by using a dual delay line system to reduce unwanted common mode signals. The simple and cheap spray coating technology for the rr-P3HT polymer films deposition, complemented with fast low level humidity detection of the tested SAW sensors (much faster than the commercially available Michell SF-52 device), highlight their potential in a low-medium range humidity sensing application.

Nitrogen deposition-induced stimulation of soil heterotrophic respiration is counteracted by biochar in a subtropical forest

Both atmospheric nitrogen (N) deposition and biochar application can markedly impact soil heterotrophic respiration (RH), an important component of the global carbon cycle. However, the interactive effects of N deposition and biochar application on soil RH in subtropical forest ecosystems remain unclear. Here, we conducted a three-year (2019–2022) field trial within a bamboo forest in subtropical China to examine the responses of soil physicochemical and microbial properties to N deposition and biochar application, and to elucidate how biochar regulates N deposition-induced change in soil RH. Nitrogen deposition stimulated soil RH by 8.1–9.8 % annually over three years compared to the control, and this stimulation was mitigated (by 8.1–8.9 % annually) with biochar addition. In the context of N deposition, the decrease of soil RH by biochar application was not through changing soil temperature, moisture or labile organic carbon content. Biochar treatment reduced the abundances of bacterial glycoside hydrolase family 48 gene (GH48) and fungal glycoside hydrolase family 7 cellobiohydrolase I gene (cbhI) and the activities of β-glucosidase and cellobiohydrolase (CBH), but increased the abundance of cbbL gene and activity of RubisCO enzyme. Furthermore, the RH was correlated positively (P < 0.01) with β-glucosidase and CBH activities and negatively (P < 0.01) with RubisCO enzyme activity. Structural equation modeling revealed that the biochar-induced reduction of soil RH under N deposition was associated with decreases in the abundance of cbhI gene and the activity of CBH in soils. We highlight that management practices can mitigate soil carbon loss in forests through modulating soil microbial functions under atmospheric N deposition, and that biochar application in Moso bamboo forests has the potential to reduce RH by approximately 7.6 × 106 t CO2 yr−1 under atmospheric N deposition.

Distribution and Frequency of ABO and Rhesus blood groups among donors at Chughtai Institute of Pathology, Lahore

Aim: To assess the demographic background of blood donors in a referral institution located in Lahore, as well as the distribution of blood groups among those who donate blood. Additionally, the study will investigate the distribution of blood groups among those who donate blood. Study design: A cross-sectional study Place of Study: Chughtai Institute of Pathology, Lahore Study duration: March to June 2023 Results: Among the participants, blood group O was most common 202(49.26%), followed by A 110(27.1%), B 82(20%) and AB 15(3.65%). Blood group O was most common. Blood group O was the least common among participants. The least common blood group was AB, with 3.65% of male participants and 1.7% of female participants. A statistical analysis found no significant difference between gender and blood type (χ2 = 2.9932, P value =0.912). All blood groups except AB had Rh-negative antigens. A comparison of blood types found no changes in RH (χ2 = 2.112, P value = 0.698). Conclusion: For the functioning of a national health service, it is crucial to possess current information on the prevalence of blood types in various local settings. Currently, there is a lack of information on this important subject. Our research provides detailed information on the blood type and demographic characteristics of donors. Additional research and mobilisation are needed nationwide to adhere to the World Health Organization's suggestions regarding voluntary blood donation. Keywords: Rhesus factor, ABO, blood donation, and transfusion medicine

Seasonal Dynamics of Soil Respiration and Its Autotrophic and Heterotrophic Components in Subtropical Camphor Forests

On a global scale, soil respiration (Rs), representing the CO2 flux between the soil surface and the atmosphere, ranks as the second-largest terrestrial carbon (C) flux. Understanding the dynamics between Rs and its autotrophic (Ra) and heterotrophic (Rh) components is necessary for accurately evaluating and predicting global C balance and net ecosystem production under environmental change. In this study, we conducted a two-year root exclusion experiment in subtropical China’s Camphor (Cinnamomum camphora (L.) Presl.) forests to assess seasonal changes in Ra and Rh and their relative contributions to Rs. Additionally, we examined the influence of environmental factors on the dynamics of Ra, Rh, and Rs. Our results showed that seasonal mean Rs values were 2.88 µmol m−2 s−1, with mean Ra and Rh of 1.21 and 1.67 µmol m−2 s−1, respectively, in the studied forests. On an annual basis, the annual values of mean Rs in the studied forests were 405 ± 219 g C m−2 year−1, with Rh and Ra accounting for 240 ± 120 and 164 ± 102 g C m−2 year−1, respectively. The seasonal mean ratio of Rh to Rs (Rh/Rs) was 58%, varying from 45 to 81%. Seasonal changes in Rs and Rh were strongly correlated with soil temperature but not soil water content. Both Rh and Rs increased exponentially with the average soil temperature measured in the topsoil layer (about 5 cm), with Q10 values of 2.02 and 1.73 for Rh and Rs, respectively. Our results suggest that the composition and activity of soil microbes and fauna play a primary role in releasing carbon flux from soil to the atmosphere in the studied forest ecosystems.

(Invited) empowering Triboelectric Nanogenerator with Functional Polymers for Environment Monitoring

Triboelectric nanogenerator (TENG) proves useful as self-powered sensor. Integration of TENG with functional polymers empowers TENG to exhibit new functionalities and stimuli responsiveness. This study describes the evaluation of spiropyran-functionalized polymer (P1) and guanidinium-functionalized polymers (2 Gdm.) as new materials for TENG, which both show tunable triboelectric output voltage in response to various environmental cues including UV irradiation, humidity change, metal ions and the presence of bacteria. Spiropyran isomerizes to merocyanine upon UV irradiation for 100s (6-8W), resulting in a decrease in output voltage from 100 V to 65 V. In addition, the output voltage is inversely proportional to the irradiation time. Noting high humidity (RH) generally limits the performance of conventional TENGs, such that the output voltage decreases as RH increases. The output voltage of P1 decreases by 48% (from 100V to 52V) and the output voltage of 2 Gdm. decreases by 85% (from 100V to 15V) as the RH changes from 25% to 88%, which is a common behavior of TENG under high humidity. In contrast, the output voltage of the UV irradiated P1 TENG increases by 30% (from 65V to 80V). Because merocyanine is capable of chelating with metal ions to form metal complexes, we also evaluate the effect of metal chelation on triboelectric voltage output. Chelation with copper(II) ions result in restoration of output voltage to ~100V, suggesting the relative position in triboelectric series can be modulated by metal complexation. For guanidinium-functionalized polymers, 2Gdm., the inherent antimicrobial properties of guanidinium side groups enables TENG to be sensitive to both gram-positive and gram-negative bacteria at a concentration of 105 CFU/mL, resulting in decreasing output voltage as bacteria concentration increases. These results demonstrate that the functionalized polymers can be used as a responsive motif to realize smart TENG systems, which exhibits sensitivity to UV irradiation, changes in humidity, and the presence of metal ions or bacteria.

Electrical Properties of Heavily Al-Doped 4H-SiC

We investigate the temperature-dependent resistivity (ρ(T)) and Hall coefficient (RH(T)) of heavily Al-doped 4H-SiC and discuss the underlying conduction mechanisms. The sign of RH(T) changes from positive to negative in nearest-neighbor hopping (NNH) and variable-range hopping (VRH) conduction, whereas it is positive in band conduction because Al-doped 4H-SiC is a p-type semiconductor. We propose a general physical model to explain why RH(T) in hopping conduction becomes negative at low temperatures, which is applicable to both NNH and VRH conduction. Moreover, we elucidate why the activation energy for negative RH(T) becomes similar to that of ρ(T) in NNH conduction.

A comparative investigation of equimolar Ni-, Ru-, Rh- and Pt-based composite structured catalysts for energy-efficient methane reforming

Hydrogen as an optimal fuel for mobile and local fuel cell-based power generators creates a request for effective on-board fossil fuel transformation to hydrogen-rich syngas. Structured catalysts based on carriers with high thermal conductivity can improve fuel conversion and decrease external heat input to a reformer through intensification of temperature distribution in the reforming processes. In this work, carriers of the structured catalysts were made from metal grids consisting of Fe, Cr, and Al alloy. Aiming to compare a catalytic activity per a one active metal atom four Me/Ce0.75Zr0.25O2/Al2O3/FeCrAlloy (Me = Ni, Ru, Pt, and Rh) catalysts with similar molar content of an active metal were prepared. The catalysts were characterized by transmission (TEM) and scanning electron microscopies (SEM), X-Ray diffraction analysis (XRD), and X-Ray photoelectron spectroscopy (XPS) before and after catalytic tests. Investigation of the catalysts’ effectivities in methane steam reforming (MSR) showed that the performances change in the order Rh > Ru > Pt > Ni. The Rh-based structured catalyst provided thermodynamic equilibrium product distribution of MSR products at a relatively low temperature of 600 °C and high flow rates. Hydrogen content in the syngas obtained in MSR over Rh-based structured catalyst was up to 70.3 vol% at the weight hour space velocity (WHSV) of 290 700 Nml⋅gacc−1⋅h−1. Investigation of methane autothermal reforming (MATR) over Pt- and Rh-based structured catalysts at 700 °C approved better performances of the Pt-based catalyst for this process. The syngas obtained in MATR over the Pt-based catalyst contained up to ∼ 40 vol% of H2 and 7.4 vol% of CO with a H2/CO molar ratio of ca. 5.5. The optimal conditions for MATR over the Pt-based catalyst were selected and the catalyst stability in long-term reforming was approved. The developed mathematical model for the description of MATR over Pt-based catalyst correlates well with the experimental data and can be used for scale-up of the process.

Generation of macro-vortices in estuarine compound channels

We report the results of a numerical investigation of the flow structure and mechanism of macro-vortex generation in estuarine compound channels. The Finite-Volume Coastal Ocean Model (FVCOM) was implemented to simulate tidal currents in compound channels, e.g., the Lantau Channel, which lies in the middle of the Pearl River Estuary (PRE). Results showed that the velocity magnitude in channels was significantly larger than that of floodplains during the ebb and flood phases, resulting in a high-velocity gradient at the depth discontinuity. Vorticity and Q-criterion were used to analyze the macro-vortex distribution inside the PRE. Massive macro-vortices were generated along the compound channels where high vorticity was also detected. The across-estuary sections with single and multiple channels were selected as representatives to analyze velocity distribution during ebb and flood tides. To characterize the channel flow, the ratio of the main channel depth of the Lantau Channel to floodplain depth (Rh) was calculated using the topography information and surface elevation of sections. It was found that there existed a channel segment where the flow periodically changed between shallow flow (Rh &amp;gt; 3) and intermediate flow (2&amp;lt; Rh&amp;lt; 3). This dynamic change in Rh greatly influenced the generation of macro-vortices. Transverse dispersive stresses were calculated to evaluate the longitudinal momentum transfer in the lateral direction. We found that the dispersive stresses could play an important role in the redistribution of momentum in addition to barotropic and baroclinic transport. This paper revealed the mechanism of the dynamic generation of macro-vortices in the estuarine compound channel, serving as a valuable example in understanding natural compound channel flows.

High-performance flexible and stretchable self-powered surface engineered PDMS-TiO2 nanocomposite based humidity sensors driven by triboelectric nanogenerator with full sensing range

Harvesting electrical charge using triboelectrification provides a promising path to realizing uninterrupted self-powered sensors with application in wearable electronics and personal healthcare. This paper reports a high-performance flexible and stretchable self-powered humidity sensor based on triboelectric nanogenerators (TENG) that provides extreme responsivity, excellent repeatability with fast recovery time, and high selectivity. The device relies on a surface-engineered titanium oxide nanoparticle-silicone nanocomposite that generates triboelectric charge density strongly dependent on ambient humidity. The performance of the nanoengineered humidity sensor was systematically investigated at different humidity levels, which exhibits high responsivity (90% change for 75% RH change), a fast response time (1 s for 50% RH), a fast recovery time (3 s for 50% RH), and nearly full sensing range (0–99%). When activated by vertical contact separation at 2 Hz, the device generates a power density as high as 90 mW.m−2 and an open-circuit voltage of 50 V. An analytical model is derived to understand the underlying mechanism. The theoretical data explain the role of dielectric permittivity and surface area on the device operation, and the results are in good agreement with the experiments. The excellent combination of the properties suggests that these flexible TENGs can serve as reliable self-powered motion-driven humidity sensor.

(Digital Presentation) Investigation of the Active Site on Rhodium Oxide for the Oxygen Reduction Reaction Using In-Situ XAFS

Polymer electrolyte fuel cells (PEFCs) are attracting attention as a next-generation power source with low environmental impact. However, the low durability and high cost of Pt-based catalysts used as electrocatalysts have hindered the widespread use of PEFCs. Currently, many studies are being conducted to improve the durability of Pt-based catalysts, such as alloying, core-shelling, and the use of oxide supports. Although these studies have achieved certain results, the high cost of raw materials cannot be avoided as long as Pt, which is a noble metal, is used to some extent. Therefore, research on non-Pt catalysts that do not use Pt is attracting attention as the next generation of electrocatalysts.Non-Pt catalysts can be broadly classified into oxide-based and carbon-based catalysts, but considering the start-up and shutdown potentials of PEFCs, oxide-based non-Pt catalysts are expected to show higher durability. It is known that the introduction of oxygen-deficient sites in the oxides of Group 4 and Group 5 elements in the oxide-based non-Pt catalysts results in a high oxygen reduction reaction rate (ORR). Therefore, oxygen-deficient sites are considered to be active sites for ORR, and the introduction of oxygen-deficient sites in the crystal lattice is a guideline for catalyst design in non-Pt catalysts based on oxides. On the other hand, it has been reported that noble metal oxides show high ORR activity even without clear oxygen-deficient sites. It is easy to imagine the hypothesis that the ORR proceeds by the adsorption of oxygen molecules on the oxygen-deficient sites, but the same hypothesis holds true for low-coordinated metal atoms on the oxide surface without the introduction of oxygen-deficient sites. Furthermore, it has been reported that in alkaline solution, oxygen atoms in the perovskite structure are the active sites. These discrepancies are due to the fact that the ORR mechanism on oxides is still unknown.In this study, in-situ XAFS measurements were performed to identify the active sites of ORR on oxides, and changes in the chemical states of metal elements during the ORR were investigated from changes in XANES spectra. A noble metal oxide (Rh2O3), whose valence changes with potential, was used as the target oxide.The target oxide, Rh2O3, was prepared by the Adams method. The prepared sample was placed on a glassy carbon plate at 100 g cm-2 and placed in a tripolar electrolytic cell for in-situ XAFS. The in-situ XAFS cell was designed to detect X-ray fluorescence by irradiating X-rays from the back of the sample. Energy of the incident X-ray was set near the Rh K edge. In-situ XAFS measurements were performed at five points: 0.4 V, where the ORR is in progress; 0.6 V and 0.8 V, near the ORR starting potential; 1.0 V and 1.2 V, where the ORR is not in progress. To investigate the effect of oxygen partial pressure, the oxygen partial pressure varied between 0%, 25%, 50%, 75%, and 100%.Comparing the height of the white line in nitrogen at 0.4 V and at 1.2 V, which is the most reducing state, the height of the white line was lower when the applied voltage was 0.4 V. This is because the average valence of Rh was higher at 0.4 V than at 1.2 V, which is the most reducing state. This indicates that the average valence of Rh changes with applied voltage. In other words, at 0.4 V, when the ORR is fully advanced, the oxidation number of Rh is considered to be in a reduced state. This behavior is consistent with the electrochemical behavior and with previous reports.In contrast, when the oxygen partial pressure was set to 25%, this difference in the applied voltage was hardly observed. The difference in the white lines between the high and low potential sides became smaller as the oxygen partial pressure increased, and under 100% oxygen, the XANES spectra obtained at the applied voltage of 0.4 V and 1.2 V almost overlapped. Therefore, unlike under a nitrogen atmosphere, the oxygen gas adsorbs on the Rh2O3 surface at 0.4 V, where the ORR proceeds under oxygen distribution. As a result, it is considered that the oxidation number of Rh increased. From the above, we predict that in Rh2O3, the ORR progresses in the state where the valence of Rh is decreased.

Influence of urban heat islands on seasonal aerosol acidity and aerosol liquid water content in humid subtropical Hong Kong, South China

Aerosol acidity governs many important atmospheric processes that modulate the composition and mass concentrations of atmospheric aerosols. Temperature and RH are two key drivers of aerosol acidity. Increasing levels of urbanization in humid subtropical South China have led to the frequent occurrence of urban heat islands (UHIs) in the region. However, the effects that UHIs have on aerosol acidity in cities in South China are currently unknown. In this study, we investigated the effects of UHIs on aerosol acidity and aerosol liquid water concentrations at two urban sites with different land use characteristics in Hong Kong, South China, in winter and summer from 2011 to 2019. Our results showed that the UHI effect resulted in both urban sites having significantly higher temperatures and lower RH than the refence rural site. Higher UHI intensities were observed in winter, but RH differences between the urban and rural sites were the greatest in summer. Temperature and RH changes associated with the UHI effect resulted in urban aerosols having aerosol liquid water concentrations that were up to 6 to 7 times lower than rural aerosols, and urban aerosols being more acidic than rural aerosols by as much as 1.16 pH units. While the pH differences between urban and rural aerosols correlated with temperature and RH differences induced by the UHI effect, these correlations were season-dependent due to differences in the winter and summer aerosol compositions. In addition, although the UHI was most intense in winter, pH differences between urban and rural aerosols were the largest in summer. Changes in temperature, RH, and aerosol liquid water concentrations linked to the UHI effect were found to lead to substantial reductions (by as much as 38%) in the partitioning of semi-volatile basic and acidic species NH3 and HNO3 to the aerosol phase. Our results indicate that changes in the aerosol acidity, aerosol liquid water concentrations, and gas-aerosol partitioning associated with UHIs have significant implications for aqueous urban aerosol chemistry in Hong Kong. Since UHIs will intensify in many cities in South China in the future due to their increasing levels of urbanization and a warming climate, changes in urban aerosol acidity and liquid water concentrations induced by intensifying UHIs need to be considered when modeling urban aerosol composition and levels in the region.

Understory plant removal counteracts tree thinning effect on soil respiration in a temperate forest.

Elucidating the response mechanism of soil respiration (Rs) to silvicultural practices is pivotal to evaluating the effects of management practices on soil carbon cycling in planted forest ecosystems. However, as common management practices, how thinning, understory plant removal, and their interactions affect Rs and its autotrophic and heterotrophic components (Ra and Rh) remains unclear. Therefore, we investigated Rs, Ra and Rh by the trenching method from 2011 to 2015 in a Pinus tabuliformis plantation in northern China, subjecting to four treatments (intact control plots [CK], thinning [T], understory removal [UR], and thinning with understory removal [TUR]). Mean annual Rs was significantly increased by thinning (by 15.3%), whereas decreased by UR (by 17.4%), compared with CK. These variations in Rs were mainly attributed to changes in Ra. The increments of Ra were caused by the enhanced growth of fine root biomass after thinning. However, UR led to lower Ra compared with CK (p < .05), indicating that understory growth is inadequate to compensate for the decreased respiring root biomass induced by understory removal. Rs was unchanged between TUR and the intact control plot due to the opposite effects of thinning and UR on the Ra. Changes in Rh exhibited no significant differences among the treatments, partly because of the stable microbial biomass carbon (MBC) and forest floor mass (litter and fine woody debris). No interaction effect between thinning and understory removal was detected on Rs, Ra, and Rh. The lowest temperature sensitivity (Q10 ) value of Ra was found in CK. This study highlights the necessity of incorporating understory plant effects on soil CO2 efflux in assessing forest management practices on soil carbon cycling.

Unjuk Kinerja Sistem Aerasi Dalam Kotak Penyimpanan Kentang (Solanum tuberrosum L) Tipe Kotak

The purpose of this study was to determine the performance of the box type potato storage aeration system in terms of changes in temperature and RH of the air during storage. Research on a box type aeration system for potato storage was carried out by measuring the temperature and RH of the incoming air, the temperature and the RH of the outgoing air during storage of potatoes for 21 days. In addition, calculating the heat of respiration, heat to increase the temperature of potatoes, heat to evaporate water and heat lost to the environment using a simple mathematical model approach. The results showed that the temperature and RH of the room and the incoming air flow tended to form a linear pattern, while the RH of the process room and the outgoing air flow tended to form a polynomial pattern. The temperature of the potato storage room was in the range of 24.07-25.70oC and the RH was in the range of 56.0-65.6%. The heat value of respiration varied between 261.42 - 311.88 k.Joule/kg potato tubers, because the storage temperature was 24.07-25.70oC. The heat generated by the respiration process used to evaporate water from the potato tubers to the environment is 6.01±0.3% on average, the average heat to raise the temperature of the potato tubers and the air temperature around the potato is 24.08±1, 3%, and the average heat loss to the environment with the flowing air is 59.89±3.4%.

Heterotrophic respiration and its proportion to total soil respiration decrease with warming but increase with clipping

Revealing how heterotrophic respiration (Rh) and its contribution to soil respiration (Rs, Rh/Rs ratio) respond to climate warming and land-use change is crucial for advancing our understanding of the feedback between the terrestrial carbon (C) cycle and future climate changes. Here we conducted a 7-year manipulation experiment by warming and clipping to explore their impacts on Rh and Rh/Rs ratio in an alpine meadow on the Qinghai-Tibet Plateau. Infrared heaters were used to simulate climate warming and clipping was applied to mimic yearly hay or biofuel harvest. We found that, on average, warming significantly decreased Rh/Rs ratio by 5.5%, which was attributed to the little change in Rh and increased autotrophic respiration (Ra, 18.3%) under warming. In contrast, clipping significantly increased Rh/Rs ratio by 8.1%, which was mainly due to the clipping-induced increase in Rh (22.6%) and decrease in Ra (3.9%). Warming or clipping-induced changes in Rh and the Rh/Rs ratio were mainly controlled by the microbial metabolic quotient, microbial biomass C and nitrogen, soil moisture, and soil temperature. Moreover, warming and clipping both increased Rs by 13.2% and 15.5%, respectively, over the study period. Our study highlights the differential responses of the two soil respiration components to warming and clipping, and suggests that climate warming does not necessarily increase Rh but clipping largely stimulates Rh, which may accelerate the turnover and losses of soil C in this alpine meadow. Hence, quantifying how Rh and the Rh/Rs ratio respond to global changes has large implications for better predicting the future ecosystem C cycle and its feedback to climate system in ecosystem models.

Superconductivity in infinite-layer nickelate La1-xCaxNiO2 thin films.

We report the observation of superconductivity in infinite-layer Ca-doped LaNiO2 (La1−xCaxNiO2) thin films and construct their phase diagram. Unlike the metal-insulator transition in Nd- and Pr-based nickelates, the undoped and underdoped La1−xCaxNiO2 thin films are entirely insulating from 300 K down to 2 K. A superconducting dome is observed at 0.15 < x < 0.3 with weakly insulating behavior at the overdoped regime. Moreover, the sign of the Hall coefficient RH changes at low temperature for samples with a higher doping level. However, distinct from the Nd- and Pr-based nickelates, the RH-sign-change temperature remains at around 35 K as the doping increases, which begs further theoretical and experimental investigation to reveal the role of the 4f orbital to the (multi)band nature of the superconducting nickelates. Our results also emphasize a notable role of lattice correlation on the multiband structures of the infinite-layer nickelates.

Extreme drought decreases soil heterotrophic respiration but not methane flux by modifying the abundance of soil microbial functional groups in alpine peatland

Extreme drought can have a substantial effect on the soil water content, soil microbial community structure and function, soil heterotrophic respiration (Rh), and soil methane (CH4) flux. However, the effects of extreme drought on Rh and CH4 flux at different plant growth stages (rapid growth, full bloom, and decline stages) and the main factors driving changes in Rh and CH4 flux remain unclear. We conducted an experiment to reveal the responses of Rh, CH4 flux, and the microbial community to extreme drought and the main factors affecting Rh and CH4 flux. Extreme drought significantly decreased Rh (from 69.41 to 31.37 mg m−2h−1) at the decline stage but had no significant effect on CH4 flux. Extreme drought significantly decreased bacterial α-diversity, markedly decreased the relative abundance of Rokubacteria and Chloroflexi at the rapid growth stage and decline stage, and significantly increased the relative abundance of Actinobacteria at the full bloom stage. At the rapid growth and full bloom stages, extreme drought significantly decreased the relative abundance of aromatic hydrocarbon degraders by 50.26% and 64.37%, respectively. At the decline stage, extreme drought significantly decreased the relative abundance of methanol oxidizers and lignin degraders by 81.63% and 82.08%, respectively. A random forest model analysis revealed the most important role of bacterial functional groups in determing Rh and CH4 flux. The aromatic compound degraders and aromatic hydrocarbon degraders amounted to 11.89 % of contribution to Rh, and aromatic compound degraders, aromatic hydrocarbon degraders, aliphatic non-methane hydrocarbon degraders, and methylotrophs amounted to 13.29 % of contribution to CH4 flux. Our findings indicate that microbial functional groups involved in carbon cycles are important factors explaining variation in Rh and CH4 flux and are critical for exploring the possible microbial response mechanism of soil carbon cycling under future scenarios of extreme drought.

Effect of Variable Conditions of Exposure on the Physical and Mechanical Properties of Blockboards

The growing demand for wood and the continued increase of the raw material price have resulted in companies using more efficient wood resources in wood-based products such as blockboard. These boards are used in the field of interior design, especially. The aim of this research was to evaluate the effect of variable environmental conditions on the physical and mechanical properties of blockboard (BK). Two types of commercial BK were exposed in variable environmental conditions (kitchen, bathroom and climatic chamber) for three months. The BK structures were composed of veneer (V) and high-density fibreboards (HDF) for the face sheets and glued, solid wood, resinous strips for the core. The temperature and relative humidity of the air (RH) ranged from 18 °C to 25 °C and from 25% to 90%, respectively. In the climatic chamber (CC), the dynamics of the parameter variations were different than in the other two exposure climates, being determined by the programmed cyclic changes in RH. The changes observed on physical and mechanical properties were more extreme for the blockboards tested in the CC than in the kitchen (K) and bathroom (Ba). After 3 months of exposure in the CC, the thickness and weight of the boards increased by 1.8 and 1.1 times, respectively, for veneered BK, and by 4.4 and 0.4 times, for BK with HDF faces, compared to values recorded in the kitchen. The panels exposed in the CC exhibited the highest increase in moisture content (MC): 41% for veneered BK and 82% for BK with HDF faces after three months of exposure, followed by those exposed in the bathroom and kitchen. Increases in MC determined decreases of flexural properties and soundness surfaces, more evident for HDF face structures compared to V ones.

The Environmental Conditions Behind the Formation of Small (subLCL) Clouds

AbstractSubLCL clouds are defined here as clouds that form below the estimated lifting condensation level (LCL), on days that are predicted to be cloud‐free. On more than 50% of those days we observed clouds. Measurements of thermodynamic and sky conditions are used here together with numerical simulations to study subLCL clouds’ formation. It was previously demonstrated that humidified parcels in mid‐boundary layer (BL) are likely to be the driving mechanism. We found the height of the LCL above the BL top and the RH near the BL top to be good predictors of the appearance of these clouds. In addition, the average change in RH in the rising parcels that form them was found to have a specific constant value (4.4 0.2[%] per 100 m of elevation). This value enables the prediction of subLCL clouds’ formation on days that rising parcels can reach saturation while moving up in the BL.

Experimental investigation into simultaneous adsorption of water vapor and methane onto shales

Methane is the main component of natural gas and a greenhouse gas. It usually coexists with water in geological formations. Methane adsorption onto shale has been studied extensively, but there is no report on the Simultaneous Adsorption of Water vapor and Methane (SAWM). This paper reports a new experimental method for studying SAWM onto shale. During the experiment, liquid water, water vapor and methane coexist in an adsorption cell. Water vapor is produced via evaporation of liquid water, and the processes of liquid water evaporation and water vapor and methane adsorption onto shale occur simultaneously. The rate of liquid water conversion into vapor and the free water vapor content in the gas mixture depend on Relative humidity (Rh). Changes in Rh are monitored with a humidity-sensor. In SAWM, the amount of water vapor adsorbed greatly exceeds that of methane. The adsorption of water vapor took longer to reach equilibrium than that of methane. The amount of water vapor adsorbed at equilibrium decreased with total pressure, while the opposite situation occurred with methane adsorption. Compared to Pure Methane adsorption onto Dry Shale (PMDS), the amount of methane adsorbed was lower by 10–59% in SAWM. The equilibrium time for methane adsorption was higher, and t50 and t80 (t50 and t80 represented the times required for adsorption of 50% and 80% of the equilibrium adsorption amount, respectively) increased 12.0–108.0 and 9.0–115.2 times, respectively. In the two experiments, the declines in the level of methane adsorption were equal when a critical threshold Equilibration Degree (Ed) was reached. Before reaching Ed, the rate of methane adsorption in SAWM was higher than that in PMDS. After reaching Ed, the phenomenon was reversed.