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Stimuli-responsive polymers have gained significant research interest in recent years owing to their potential applications in diverse areas. Here, we present a study on the actuation characteristics of chitosan-based free-standing films that exhibit full reversibility and repeatability in response to water vapor exposure. The effect of pH of the water and the degree of cross-linking of the chitosan films on the actuation performance is studied. In the case of free-standing polymer film-based actuators, the primary driving force behind actuation is understood to be the differential strain induced by the gradient in volume changes across the thickness of the film. To understand it further, we conducted full atomistic molecular dynamics simulation studies to explore water absorption and adsorption into the chitosan matrix. Our simulations revealed an accumulation of water molecules in the surface layer that rapidly desorb when shielded from water vapor. Furthermore, estimates of the energy gain resulting from the adsorption of water on the surface suggest that it is adequate to drive the shape change of the actuator when subjected to asymmetric exposure to water vapor. This finding supports the fact that the adsorbed layer of water on the surface of the chitosan film plays a role in actuation. [ABSTRACT FROM AUTHOR]

GaN grown via oxide vapor phase epitaxy (OVPE-GaN) can produce free-standing substrates with ultra-low resistivity because of the high doping concentration of oxygen. The bulk growth of OVPE-GaN is hindered by polycrystals generated during long-term growth. We have previously reported that thicker films can be grown by reducing the partial pressure of water vapor in the growth atmosphere with CH4. However, as CH4 is a dopant of carbon, a compensating acceptor, its addition may increase electrical resistance. In this study, we further investigated the effect of reducing water vapor partial pressure on polycrystals by combining Ga2O production (reaction of Ga and water vapor: a Ga–H2O system), which can reduce water vapor, with CH4 addition. However, CH4 addition to the Ga–H2O system increased polycrystal generation, possibly owing to the thermal decomposition of excess CH4. The properties of OVPE-GaN with CH4 addition were also evaluated. Although the CH4 addition resulted in high carbon doping, the carbon-doped OVPE-GaN maintained low resistivity. This is because the OVPE method involves three-dimensional growth with growth pits, and the growth pits leave behind low-resistivity high-oxygen-concentration regions. As the resistivity remains low even when CH4 is added in the OVPE method, both polycrystallization suppression and low resistivity can be achieved by selecting an appropriate CH4 flow rate. [ABSTRACT FROM AUTHOR]

A femtosecond laser induced photofragmentation fluorescence (fs-LIPF) scheme for the sensitive detection and imaging of water vapor is presented. Two photons of 244.3 nm excite water to the D ̃ state and produce hydroxyl radicals in the fluorescing A ̃ state. Two more photons promote electrons from the D ̃ state to a neutral Rydberg state of the (1b2)−1 ionic core through a 2 + 2 doubly resonant process. The resulting high-lying Rydberg state undergoes neutral dissociation, and the energetic hydrogen fragments are detected from their Balmer series fluorescence. These channels (in the low-pressure limit) have detection sensitivities around 1012 molecules per cubic centimeters, orders of magnitude more sensitive than laser-induced fluorescence based approaches, allowing for sensitive non-invasive detection and imaging of water density for many important processes. [ABSTRACT FROM AUTHOR]

Molecular-level nucleation has not been clearly understood due to the complexity of multi-body potentials and the stochastic, rare nature of the process. This work utilizes molecular dynamics (MD) simulations, incorporating a first-principles-based deep neural network (DNN) potential model, to investigate homogeneous water vapor condensation. The nucleation rates and critical nucleus sizes predicted by the DNN model are compared against commonly used semi-empirical models, namely extended simple point charge (SPC/E), TIP4P, and OPC, in addition to classical nucleation theory (CNT). The nucleation rates from the DNN model are comparable with those from the OPC model yet surpass the rates from the SPC/E and TIP4P models, a discrepancy that could mainly arise from the overestimated bulk free energy by SPC/E and TIP4P. The surface free energy predicted by CNT is lower than that in MD simulations, while its bulk free energy is higher than that in MD simulations, irrespective of the potential model used. Further analysis of cluster properties with the DNN model unveils pronounced variations of O–H bond length and H–O–H bond angle, along with averaged bond lengths and angles that are enlarged during embryonic cluster formation. Properties such as cluster surface free energy and liquid-to-vapor density transition profiles exhibit significant deviations from CNT assumptions. [ABSTRACT FROM AUTHOR]

We have developed an experimental and analytical setup for thermal desorption spectroscopy of solid water films on surfaces. We obtain the coverage-dependent desorption kinetics of water molecules from a well-defined ultra-thin alumina/NiAl(110) surface in the coverage range of 0–2 monolayers. We use a novel deconvolution technique to eliminate the pumping delay of water vapor in the vacuum system, which has previously hindered the accurate estimation of desorption kinetic parameters, such as activation energy and pre-exponential factor. The coverage-dependent Arrhenius analysis reveals that the desorption activation energy decreases with increasing coverage in the sub-monolayer range, indicating that the water–water interaction is not attractive. We also find that the pre-exponential factor for the second layer is higher than that for the sub-monolayer. We explain this difference in terms of transition state theory and propose that entropic effects play a significant role in water desorption kinetics. [ABSTRACT FROM AUTHOR]

This article presents methodological advances in the state-of-the-art for making time-dependent, thermochemical measurements within kilogram-scale explosive post-detonation fireballs utilizing tunable laser absorption spectroscopy. This measurement capability is critical for validating multi-scale, multi-physics models of post-detonation dynamics. The technique is based on hardened gauges built around rapidly-tunable lasers and custom post-processing algorithms that provide quantitative thermochemical data interior to large and opaque explosive fireballs. The authors present a holistic overview of the technique including gauge design, the laser absorption diagnostic, and the custom data processing algorithms. Additionally, fielding high-bandwidth laser absorption probes at stand-off ranges presents new challenges in data processing that must compensate for long distance signal transmission effects. We highlight representative data from a hardened gauge measurement at 0.81 m stand-off from a 2.78 kg LX-14 explosive charge detonated in an outdoor test arena. We discuss progress in all-optical measurement of temperature, pressure, and water vapor number density at a 100 kHz repetition rate during the first 10 ms of the fireball evolution. We conclude the article with a brief discussion on our current approach for comparing hardened gauge measurements with computational fluid dynamic simulations. [ABSTRACT FROM AUTHOR]

Using adiabatic molecular dynamics coupled with the fluid dynamics equations, we model nucleation in an expanding beam of water vapor and argon on a microsecond scale. The size distribution of clusters, their temperature, and pickup cross sections in dependence on velocity are investigated and compared to the geometric cross sections and the experiment. The clusters are warmer than the expanding gas because of the time scale of relaxation processes. We also suggest that their translational and rotational kinetic energies are modified due to evaporative cooling. The pickup cross sections determined for the final clusters using molecules of the same kind increase with decreasing velocity, still obeying the (a + b N 1 / 3 ) 2 law. [ABSTRACT FROM AUTHOR]

Rationale: Laser‐based analyzers are widely used in ecohydrology to analyze plant water isotopic compositions (δ18O and δ2H). The suitability of three different water extraction and isotope equilibration techniques was compared. We examined whether co‐extracted volatile organic compounds (VOCs) affect laser‐based isotope measurements and used the instrument's spectral parameters to post‐correct for interfering VOCs. Methods: Cryogenic vacuum extraction, vapor headspace equilibration in bags, and vapor equilibration in situ probes were used to extract liquid water or water vapor for laser‐based isotope analysis (cavity ring‐down spectrometry, CRDS). Isotope data were calibrated by standards for each method separately. Spectral parameters of the instrument, appropriate to identify spectral interferences with MeOH and CH4, were identified and used for post‐correction. Differences between the three methods and between the origins of the vegetables were identified by statistical tests. Results: VOCs were found in various amounts for the three different methods. They were co‐extracted or co‐equilibrated during the different extraction or equilibration methods. Correlation coefficients of isotope data and "CH4" (spectral parameter) were 0.99 or better; however, slopes for δ18O were similar on different instrument types but different for δ2H. Our correction approach improved results and inter‐comparability of the methods considerably without knowing the chemical composition of the plant sap. Conclusions: All three methods were sensitive enough to distinguish and resolve differences in natural abundance. Data quality was improved by the "CH4 correction" approach but could probably be optimized by a plant species–specific correction. Standardized tools for contaminant removal or post‐correction applications from manufacturers, in particular for vapor‐mode analysis, are still needed. [ABSTRACT FROM AUTHOR]

Materials with a thermal expansion coefficient compatible with silicon carbide based ceramic matrix composites and low thermal conductivity at higher temperatures are crucial for developing environmental barrier coatings (EBCs) for aero-engines. Lately, high entropy silicate engineering has been a promising approach to develop optimized EBC materials. The solid solution reaction method was adopted for the fabrication of high entropy multicomponent (Dy 1/5 Er 1/5 Tm 1/5 Yb 1/5 Y 1/5) 2 SiO 5 or (5RE 1/5) 2 SiO 5 monosilicate. Scanning electron microscopy and X-ray diffraction show the homogenous distribution and a single-phase solution of (5RE 1/5) 2 SiO 5 monosilicate. Differential scanning calorimetry testing was done at 1450 °C which shows no exo/endothermic reaction has occurred. The value of the coefficient of thermal expansion (6 ppm/°C) up to temperature 1500 °C and low thermal conductivity values for (5RE 1/5) 2 SiO 5 monosilicate were observed (1.1–1.4 W/m°C) in the temperature range between 25 and 1500 °C. The water vapor corrosion resistance of (5RE 1/5) 2 SiO 5 monosilicate further confirms that the material is suitable for EBC applications due to the synergistic effect of different rare earth radii and stable crystal structure with a negligible weight loss value of 0.0005 mg/cm2 after 150 h corrosion time under 90 % H 2 O and 10 % O 2 at 1300 °C. The results of this work suggest that (5RE 1/5) 2 SiO 5 monosilicate can be used as a promising candidate for environmental barrier coatings. [ABSTRACT FROM AUTHOR]

Global average upper atmosphere temperature changes linked with the Hunga volcanic eruption (January 2022) are analyzed based on satellite measurements and compared with chemistry‐climate model simulations. Results show stratospheric cooling of −0.5 to −1.0 K in the middle and upper stratosphere during 2022 through middle 2023, followed by stronger cooling (−1.0 to −2.0 K) in the mesosphere after middle 2023. The cooling patterns follow the upward propagating water vapor (H2O) anomalies from Hunga, and similar behavior is found between observations and model simulations. While the stratospheric cooling is mainly due to radiative cooling from enhanced H2O, the mesospheric temperature changes result from ozone losses in the mesosphere, which are in‐turn driven by HOx radicals from Hunga H2O. Comparisons with the multi‐decade climate record show that Hunga impacts on stratospheric temperatures have similar magnitude, but opposite sign, to temperature effects from the large El Chichón (1982) and Pinatubo (1991) volcanic eruptions. Plain Language Summary: We analyze temperature changes in the upper atmosphere due to the Hunga volcanic eruption in January 2022 using satellite observations and simulations from a state‐of‐the‐art chemistry‐climate model. Hunga was an underwater volcano that emitted a large amount of water vapor (H2O) directly into the stratosphere, and this H2O has moved slowly upwards over time and mostly remains in the upper atmosphere. Observations show cooling of the stratosphere (20–50 km) by 0.5–1.0 K during 2022 to middle 2023, and cooling of the mesosphere (50–80 km) by 1.0–2.0 K after middle 2023. The cooling patterns follow the upward moving Hunga H2O plume. The model simulations show good agreement with observations, and the model is used to diagnose that the cooling is due to Hunga H2O impacts. The long‐lasting, global‐scale cooling from Hunga has similar magnitude, but opposite sign, to stratospheric warming observed from previous large volcanic eruptions (El Chichón in 1982 and Pinatubo in 1991); the differences are due to the large H2O emitted by Hunga. Key Points: Global average cooling of 1–2 K is observed in the upper atmosphere during 2022–2024 following Hunga eruption in January 2022Good agreement of observations with chemistry‐climate model simulations; cooling is mainly due to Hunga H2O impactsHunga‐forced cooling is comparable in magnitude to stratospheric warming following El Chichón (1982) and Pinatubo (1991) eruptions [ABSTRACT FROM AUTHOR]

Short peptides are versatile molecules for the construction of supramolecular materials. Most reported peptide materials are hydrophobic, stiff, and show limited response to environmental conditions in the solid‐state. Herein, we describe a design strategy for minimalistic supramolecular metallo‐peptide nanofibers that, depending on their sequence, change stiffness, or reversibly assemble in the solid‐state, in response to changes in relative humidity (RH). We tested a series of histidine (H) containing dipeptides with varying hydrophobicity, XH, where X is G, A, L, Y (glycine, alanine, leucine, and tyrosine). The one‐dimensional fiber formation is supported by metal coordination and dynamic H‐bonds. Solvent conditions were identified where GH/Zn and AH/Zn formed gels that upon air‐drying gave rise to nanofibers. Upon exposure of the nanofiber networks to increasing RH, a reduction in stiffness was observed with GH/Zn fibers reversibly (dis‐)assembled at 60–70 % RH driven by a rebalancing of hydrogen bonding interactions between peptides and water. When these metallo‐peptide nanofibers were deposited on the surface of polyimide films and exposed to varying RH, peptide/water‐vapor interactions in the solid‐state mechanically transferred to the polymer film, leading to the rapid and reversible folding‐unfolding of the films, thus demonstrating RH‐responsive actuation. [ABSTRACT FROM AUTHOR]

Stratospheric transit time distributions (age‐of‐air spectra) are estimated using time series of satellite water vapor (H2O) measurements from the Microwave Limb Sounder over 2004 to 2021 assuming stationary transport. Latitude‐altitude dependent spectra are derived from correlations of interannual H2O anomalies with respect to the tropical tropopause source region, fitted with an inverse Gaussian distribution function. The reconstructions accurately capture interannual H2O variability in the "tropical pipe" and near‐global lower stratosphere, regions of relatively fast transport (∼1–2 years) in the Brewer‐Dobson circulation. The calculations provide novel observational estimates of the corresponding "short transit‐time" part of the age spectrum in these regions, including the mode. However, the H2O results do not constrain the longer transit‐time "tail" of the age spectra, and the mean age of air and spectral widths are systematically underestimated compared to other data. We compare observational results with parallel calculations applied to the WACCM chemistry‐climate model and the CLaMS chemistry‐transport model, and additionally evaluate the method in CLaMS by comparing with spectra from idealized pulse tracers. Because the age spectra accurately capture H2O interannual variations originating from the tropical tropopause, they can be used to identify "other" sources of variability in the lower stratosphere, and we use these calculations to quantify H2O anomalies in the Southern Hemisphere linked to the Australian New Years fires in early 2020 and the Hunga volcanic eruption in 2022. Plain Language Summary: Stratospheric water vapor (H2O) is mainly controlled by transport across the cold tropical tropopause, which sets the entry value for the global stratosphere. Interannual variations in H2O originate near the tropical tropopause and then propagate throughout the stratosphere with the global Brewer‐Dobson circulation (BDC), where anomalies are lagged in time and smoothed by mixing. We use the observed time series of H2O from the Microwave Limb Sounder during 2004–2021 to calculate transit time distributions (also called age spectra) from the tropical tropopause source region. The results capture H2O variability in the tropics up to 30 km and in the global lower stratosphere, regions of relatively fast transport (∼1–2 years) in the BDC. The calculations provide novel observational estimates of the age spectra in these regions. The calculations are straightforward to apply to global models, and we compare observational results with simulations from the WACCM and CLaMS models. Key Points: Stratospheric transit time distributions (age spectra) are derived from time series of satellite water vapor measurementsWater vapor reconstructions from age spectra capture detailed variability in the tropics up to 30 km and in the global lower stratosphereAge spectrum results are compared between observations and global model simulations [ABSTRACT FROM AUTHOR]

The atmospheric activity on Kalimantan Island (KI) is important for regulating regional weather and climate. This study investigates the effect of autumn soil moisture over KI on following winter precipitation over southern China (SC) during 1968–2014. The results show that the autumn soil moisture over the KI has a significant negative correlation with subsequent winter precipitation over SC. The correlation remains statistically significant when using partial correlation to filter out the concurrent influences of El Niño–Southern Oscillation (ENSO) and Indian Ocean Dipole (IOD) signals. The soil moisture anomalies over KI, which initiate in the autumn and persist into the winter, lead to changes in local thermal conditions and atmospheric temperature. Negative soil moisture anomalies over KI will result in positive heating anomalies of the atmosphere above the land surface. This atmospheric heating causes ascending motion, which creates a semi‐closed vertical circulation from KI to the tropical northwest Pacific. This vertical circulation would strengthen the northwest Pacific anticyclone and weaken the East Asian winter monsoon (EAWM). Consequently, southwesterly water vapour flux prevails in the SC as well as the South China Sea (SCS), facilitating the transportation of more water vapour into the SC. Simultaneously, water vapour convergence in the SC. Collectively, these contribute to an addition of precipitation over SC. [ABSTRACT FROM AUTHOR]

Based on the observed maximum temperature (Tmax), relative humidity (RH) and NCEP/NCAR reanalysis data during 1981–2021, basic temporal features and dominant atmospheric circulation patterns of dry‐type and humid‐type heatwaves in North China are investigated and compared. Statistical results indicate the dry heatwaves occur mainly in early summer (from early June to early July), that is, before the rainy season of North China, while the humid heatwaves have a high frequency in mid‐July to mid‐August. During the research period, the increasing trend of dry heatwaves is 0.67 days·decade−1, while the humid heatwaves increase at a greatly higher rate of 1.85 days·decade−1. For the dry heatwave, a high ridge in the subtropical westerlies plays the main role, and the northerly wind in the east of the ridge reduces the air moisture convergence over the region. However, for the humid heatwave, the westward and northward propagations of the western Pacific subtropical high (WPSH) may make the major contribution, and the southerly wind anomalies in the west of the WPSH enlarge the water vapour to the region. The adiabatic heating in subsiding air at all levels and horizontal temperature advection at lower troposphere are stronger for dry heatwaves than for humid heatwaves, which cause a higher Tmax for the former type. These results highlight the diversity of the heatwaves in North China, which suggests that multiple local and large‐scale subseasonal circulations should be considered to improve the subseasonal to seasonal forecast skills for heat extremes. [ABSTRACT FROM AUTHOR]

Rainfall in East Asia is affected by two rain‐bearing systems: tropical cyclones and monsoon‐related frontal systems. Distinguishing typhoon rainfall (TR) and non‐typhoon rainfall (non‐TR) helps to understand the evolution process of regional rainfall at different timescales. Taking Fujian Province in the southeast coast of China as an example, based on the fixed box approach of separating TR, the method of determining the size of fixed box is explored. TR and non‐TR are separated in Fujian Province, and the spatial variations of TR and non‐TR at different timescales (annual, monthly, day of annual‐maximum‐rain) are analysed. The results showed that (1) according to the relationship between the sizes of fixed box and the rate of change of TR, the size of fixed box could be reasonably determined; thus, the expended size of fixed box suitable for separating TR in Fujian was 3.5°, namely the range of 20°–31.8°N and 112.3°–124.2°E. (2) The spatial variations of TR at different timescales in Fujian were similar: TR decreased from the coast to the inland, and the northeast coast of Fujian was the high‐value region. Due to the difference of water vapour sources, non‐TR in March–June increased from the coast to the inland, but the high value of non‐TR in July–September was distributed in the eastern coast. (3) The contribution rates of average TR to the total rainfall of the year, July–September and 1 day were 12.8%, 34.6% and 35.7%, respectively. In eastern coast, TR in July–September accounted for 1/3–1/2 of total rainfall, and the rainfall in a day was mainly affected by TR; while in western inland, rainfall was mainly non‐TR and the influence of TR was less than 1/4. [ABSTRACT FROM AUTHOR]

We present one year of δD, δ18O, d-excess, and Δʹ17O data from monthly precipitation at a Caribbean coastal site in Panama and from tap waters across the country to constrain geographic, climate, and moisture source controls on isotopic variability and better understand the sources and mechanisms of precipitation in Central America, a region facing significant modifications to the annual rainfall cycle due to climate change. Monthly precipitation δD ranged from –52.2 to +14.3 ‰, δ18O from –7.6 to +0.4 ‰, d-excess from +7.1 to +11.6 ‰, and Δ′17O from +11 to +29 per meg. Rainy season precipitation samples were found to have lower δD, δ18O, and d-excess due to Rayleigh distillation during the condensation and rainout of Pacific moisture over the central cordilleras, which results in decoupling between d-excess and Δ′17O. Outlier Δ′17O values during peak dry and rainy months may reflect seasonal changes in water vapor sourcing, from Caribbean to Pacific and/or locally recycled moisture, or may be a result of organic contamination. Tap water δD ranged from –82.3 to –14.3 ‰, δ18O from –11.6 to –2.4 ‰, d-excess from +4.3 to +12.2 ‰ and Δ′17O from –2 to +84 per meg. Tap water δD and δ18O values increase eastward due to lower orographic effects and Pacific and locally recycled moisture contributions to rainfall and greater secondary evaporation. Tap water d-excess and Δ′17O values are also de-coupled but lack clear spatial trends and controls. The results of this study indicate the promise of adding Δ′17O to the isotopic toolkit in tropical mountainous regions with complicated water cycling dynamics and provide a baseline for future triple oxygen isotope investigations. [ABSTRACT FROM AUTHOR]

Studying the atmospheres of exoplanets is one of the most promising ways to learn about distant worlds beyond our solar system. The composition of an exoplanet's atmosphere can provide critical insights into its geology and potential habitability. For instance, the presence of certain molecules such as water vapor, oxygen, or methane have been proposed to indicate the possibility of life. From an observation point of view, over the past fifteen years, significant progress has been made in characterizing exoplanetary atmospheres. This work reviews recent developments in ground-based high-resolution spectroscopic instruments that make it possible to analyze distant atmospheres in great detail. High-resolution transmission spectroscopy, one of the most effective methods used, has examined the atmospheres of Jupiter-like and is pushing towards the smaller, sub-Neptunian exoplanets. Numerous molecules have been detected using this technique, including CO , H 2 O , TiO , HCN , CH 4 , NH 3 , C 2 H 2 , OH . We explore the intriguing possibilities that lie ahead for future ground-based instrumentation, particularly in the context of detecting biologically relevant molecules within Earth-analog exoplanetary atmospheres including molecular oxygen ( O 2 ). With detailed exposure time calculations for detecting O 2 we find that at the same exposure time spectral resolution of 300,000 reaches higher significance compared to 100,000. The exposure time and therefore the needed number of transits is reduced by a factor of 4 in challenging haze and cloud scenarios. [ABSTRACT FROM AUTHOR]

Poly(butylene adipate‐co‐terephthalate) (PBAT) is popular because of its low cost, biodegradability, good processing properties, flexibility, and mechanical features. In this study, we explore the potential of PBAT‐based bioplastics by adding AgVO3 nanorods with PBAT to reduce costs. We produced nanocomposite films of PBAT reinforced with 1, 3, and 5 wt% of AgVO3 nanorods using solvent casting. The inclusion of AgVO3 in the structure of PBAT was investigated through Fourier transform infrared spectroscopy, x‐ray diffraction, and scanning electron microscopy. The nanocomposite films demonstrate excellent properties, surpassing those of single‐component blends, enhancing mechanical properties, and improving the barrier properties of nanocomposite films. The water vapor transmission rate of AgVO3 reinforced (5 wt%) nanocomposite films improved by 42.45% compared to pure PBAT films. The tensile strength of the PBA‐3 film was 37.19 MPa, exhibiting higher strength than the films produced from clean PBAT (19.73 MPa). The AgVO3‐reinforced films demonstrated increased resistance to moisture and water, as indicated by their higher water contact angle values (88.04°). Food‐borne bacteria like Staphylococcus aureus and Escherichia coli have been stable to the antibacterial activity of the nanocomposites on the addition of AgVO3.The potential applications of these nanocomposite films in food packaging are promising, offering a sustainable and effective solution to food preservation. Highlights: The AgVO3‐filled poly(butylene adipate‐co‐terephthalate) (PBAT) nanocomposite films exhibit superior mechanical, barrier, and resistance to moisture and water compared to neat PBAT films.The water vapor transmission rate of the film is significantly enhanced, with a 42.45% enhancement in films reinforced with 5 wt% AgVO3.AgVO3‐filled PBAT nanocomposites demonstrate effective antibacterial activity against Escherichia coli and Staphylococcus aureus. [ABSTRACT FROM AUTHOR]

Poly(lactide)/poly(butylene adipate‐co‐terephthalate) (PLA/PBAT) blends containing different amounts of polyethylene wax (PEW) were fabricated via melt‐blending, and the effects of PEW on the interfacial morphological evolution and properties of the PLA/PBAT blends were investigated. Scanning electron microscopy (SEM) micrographs show that the compatibility between PLA and PBAT is obviously improved by addition of low contents of PEW. Differential scanning calorimeter (DSC) results indicate that PEW can simultaneously enhance the crystallization ability of PLA and PBAT. Rheological behavior of the blends indicates that PEW has a significant plasticizing effect and can promote the mobility of polymer chains in the blends. More importantly, it is revealed that PEW can effectively improve the mechanical and barrier properties of the blends. Even with a PEW content of only 1 wt%, the elongation at break and notched impact strength of the blend reach 344.1% and 12.55 kJ/m2, respectively, which are 54% and 140% higher than the blend without PEW. Meanwhile, the water vapor transmission rate (WVTR) and oxygen transmission rate (OTR) of the films containing 1 wt% PEW are decreased from 87.34 to 67.40 g m−2·24 h−1 and from 118.26 to 80.94 cm3 m−2·24 h−1, respectively, which are 22.8% and 31.5% lower than those of the PLA/PBAT film. [ABSTRACT FROM AUTHOR]

This study investigates the effect of oxidized sucrose (OS) on selected functional properties of cast films from lupin protein isolate (LPI). LPI with a protein content larger than 0.9 g g−1 was obtained by alkaline extraction and isoelectric precipitation from bitter narrow‐leaved lupins (Lupinus angustifolius L.). OS was synthesized by vicinal diol cleavage using sodium periodate and was successfully characterized by Fourier‐transform infrared‐, 1H‐nuclear magnetic resonance spectroscopy, and aldehyde titration. Films were produced from heated (85°C, 30 min), alkaline (pH 10), aqueous solutions of LPI (0.1 mL−1), glycerol (300 mg g−1 of LPI) and OS (25, 50, 75, and 100 mg g−1 of LPI). The effect of covalent crosslinking between OS and protein chains was studied by investigating mechanical properties, moisture content, total soluble matter, water vapor permeability, and protein solubility for all films. LPI films produced with the addition of OS showed increased mechanical performance as the tensile strength was increased from 3.5 up to 9.3 MPa and elongation at break values could be raised from 118% to 176%. Taken together with the facts that these films are thermoformable and show improved wet strength compared with control films, make them promising materials for sustainable packaging and short‐term applications in agriculture and forestry. [ABSTRACT FROM AUTHOR]

Traditional methodologies, such as mass spectrometry and laser spectroscopy, have been widely employed for precise water vapor isotope measurements. Nevertheless, these techniques are limited by logistical challenges in fieldwork, consequently constraining the temporal and spatial resolution of measurements. Specifically, water vapor isotope measurements are primarily limited to near-surface levels, while measurements associated with processes aloft connecting tropospheric water vapor to surface precipitation are notably scarce. Portable sampling devices, such as air bags and glass bottles, have therefore become necessary alternatives for collecting, storing, and transporting gaseous samples in diverse environments prior to analysis with less portable instruments. In drone-based high-altitude vapor sampling, air bags are preferred for their lighter weight and greater flexibility compared to glass bottles. Nevertheless, they present specific challenges, such as potential sample contamination and isotopic fractionation during storage, primarily due to the inherent permeability of air bags. Here, we developed a theoretical model for water vapor diffusion through the sampling bag surface, with parameters calibrated through laboratory experiments. This model enables the reconstruction of the initial isotopic composition of sampled vapor based on measurements obtained within the bag and from the surrounding environment. We applied this correction method to air samples collected at various pressures up to the upper troposphere using an air bag-mounted drone that we developed, thereby estimating the initial isotopic composition and uncertainty based on our observations. The corrected observations closely match the IASI satellite data. Our correction method significantly enhances the reliability and applicability of water vapor isotope observations conducted using drones equipped with air bags. This approach leverages the strengths of drone-based air bag sampling while mitigating its limitations, thus facilitating the convenient collection of isotopic data throughout the troposphere. [ABSTRACT FROM AUTHOR]

Poleward water vapor transport in the midlatitudes mainly occurs in meandering filaments of intense water vapor transport, spanning thousands of kilometers long and hundreds of kilometers wide and moving eastward. The water vapor filaments are known as atmospheric rivers (ARs). They can cause extreme wind gusts, intense precipitation, and flooding along densely populated coastal regions. Many recent studies about ARs focused on the statistical analyses of ARs, but a process-level understanding of ARs remains elusive. Here we show that ARs are streams of air with enhanced vapor kinetic energy (VKE) and derive a governing equation for Integrated VKE to understand what contributes to the evolution of ARs. We find that ARs grow mainly because of potential energy conversion to kinetic energy, decay largely owing to condensation and turbulence, and the eastward movement is primarily due to horizontal advection of VKE. Our VKE framework complements the integrated vapor transport framework, which is popular for identifying ARs but lacks a prognostic equation for understanding the physical processes. A vapor kinetic energy analysis shows that atmospheric rivers' strong winds result from the conversion of potential energy into kinetic energy, and their eastward movement is primarily driven by the horizontal transport of water vapor and kinetic energy. [ABSTRACT FROM AUTHOR]

This study successfully developed a bio-based, photocurable, anionic–nonionic dual-functional chain extender, and sulfonated cardanol-based polyethylene glycol (SCP), derived from renewable resources—cardanol and polyethylene glycol—for application in waterborne polyurethane dispersions (WPUDs). Utilizing SCP as a chain extender, WPUDs were prepared through a typical acetone process with poly(butylene adipate) (PBA), isophorone diisocyanate (IPDI), and ethylene diamine (EDA) at a constant NCO/OH ratio of 1:1. This research focused on the effects of polyethylene glycol molecular weight and SCP dosage on the particle size, stability, and film-forming properties of the WPUD. Optimal dispersion stability and film-forming performance were achieved with a polyethylene glycol molecular weight of 1500 and a PBA to SCP molar ratio of 4:1, yielding a particle size of 0.326 ± 0.010 μm and excellent storage stability over six months. The resulting WPU coatings exhibited a tensile strength of 11.4 MPa, which increased to 16.8 MPa after UV irradiation owing to the formation of a semi-interpenetrating network via the photopolymerization of cardanol's unsaturated side chains. UV cross-linking also enhanced water resistance, reducing the water absorption rate (WAR) from 18.68% to 4.21% and the water vapor transmission rate (WVTR) from 6.59 × 10−5 g·m⁻¹·Pa⁻¹·d⁻¹ to 2.26 × 10⁻⁵ g·m⁻¹·Pa⁻¹·d⁻¹, while also improving thermal stability. These findings demonstrate that SCP offers a sustainable and effective solution for developing high-performance WPU coatings. [ABSTRACT FROM AUTHOR]

Digestate is a product with valuable fertilizing properties, remaining after the anaerobic fermentation process. An essential feature of the substance in question is its high water content of up to 97%. To improve the fertilizer value of the digestate, it is necessary to dehydrate it to produce a concentrated product. This paper determined the possibility of dewatering the digestate using an innovative reactor design. The study, conducted on a laboratory scale, used digestate from a Polish biogas plant. The dewatering technique described in the paper is based on the evaporation and condensation of water vapor on the inner surface of the reactor dome. The condensate accumulated on the leach trough and was directed to a storage tank. During the weeks of testing, 11.5 kg of condensate was separated from the initial weight of the digestate (32 kg), with a dry weight of 6.11%. The resulting condensate from dehydration had an average pH value of 9.0 and an average ammonium nitrogen content of 2.07 g∙kg−1. The economic calculations made in the paper allowed for estimating the expected savings associated with the management of digestate in Poland. The research showed the proposed technology's high potential for dewatering digestate under laboratory conditions. [ABSTRACT FROM AUTHOR]

Satellite remote sensing is the best way to derive sea surface skin temperature (SSTskin) in the Arctic. However, as surface temperature retrieval algorithms in the infrared (IR) part of the electromagnetic spectrum are designed to compensate for atmospheric effects mainly due to water vapor, MODIS SSTskin retrievals have larger uncertainties at high latitudes where the atmosphere is very dry and cold, which is an extreme in the distribution of global conditions. MODIS R2019 SSTskin fields are currently derived using latitudinally and monthly dependent algorithm coefficients, including an additional band above 60°N to better represent the effects of Arctic atmospheres. However, the R2019 processing of MODIS SSTskin still has some unrevealed error characteristics. This study uses 21 years (2002–2022) of collocated, simultaneous satellite brightness temperature (BT) data from Aqua MODIS and in situ buoy-measured subsurface temperature data from iQuam for validation. Unlike elsewhere over the oceans, the 11 μm and 12 μm BT differences are poorly related to the column water vapor at high latitudes, resulting in poor atmospheric water vapor correction. Anomalous BT difference signals are identified, caused by the temperature and humidity inversions in the lower troposphere, which are especially significant during the summer. Although the existence of negative BT differences is physically reasonable, this makes the retrieval algorithm lose its effectiveness. Moreover, the statistics of the MODIS SSTskin data when compared with the iQuam buoy temperature data show large differences (in terms of mean and standard deviation) for the matchups at the Northern Atlantic and Pacific sides of the Arctic due to the disparity of in situ measurements and distinct surface and vertical atmospheric conditions. Therefore, it is necessary to further improve the retrieval algorithms to obtain more accurate MODIS SSTskin data to study surface ocean processes and climate change in the Arctic. [ABSTRACT FROM AUTHOR]

Convection monitoring and forecasting are crucial for air traffic management as they can lead to the development of intense thunderstorms and hazards such as severe turbulence and icing, lightning activity, microbursts and hail that affect aviation safety. The airport of Burgas is located in southeast Bulgaria on the Black Sea coast and occurrences of intense thunderstorms are mainly observed in the warm season between May and September. This work presents an analysis of severe convection over southeast Bulgaria on 17 September 2022. In the late afternoon, a gust front was formed that reached the Burgas airport with a wind speed exceeding 45 m/s, the record for the past 50 years, damaging the instrument landing system of the airport. To analyse the severe weather conditions, we combine state-of-the-art observations from satellite and radar with the upper-air sounding and surface. The studied period was dominated by the presence of a very unstable air mass over southeast Bulgaria ahead of the atmospheric front. As convection developed and moved east towards Burgas, it had four characteristics of severe deep convection, including gravitational waves at the overshooting cloud top, a cold U-shape, a flanking line and a cloud top temperature below −70 °C. The positive integrated water vapour (IWV) rate of change preceded the lightning activity peak by 30 min. Analysis of integrated vapour transport (IVT) gives higher values by a factor of two compared to climatology associated with the atmospheric river covering the eastern Mediterranean sea. [ABSTRACT FROM AUTHOR]

Utilizing CloudSat/CALIPSO satellite data and ERA5 reanalysis data from 2007 to 2016, this study analyzed the distributions of optical and physical characteristics and change characteristics of ice clouds over the Tibetan Plateau (TP). The results show that the frequency of ice clouds in the cold season (November to March) on the plateau is over 80%, while in the warm season (May to September) it is around 60%. The average cloud base height of ice clouds in the warm season is 3–5 km, and mostly around 2 km in the cold season. The average cloud top height in the warm season is around 5–8 km, while in the cold season it is mainly around 4.5 km. The average thickness of ice clouds in both seasons is around 2 km. The statistical results of microphysical characteristics show that the ice water content is around 10−1 to 103 mg/m3, and the effective radius of ice clouds is mainly in the range of 10–90 μm. Both have their highest frequency in the west of the TP and lowest in the northeast. A comprehensive analysis of the change in temperature, water vapor, and ice cloud occurrence frequency shows that the rate of increase in water vapor in the warm season is greater than that in the cold season, while the rates of increase in both surface temperature and ice cloud occurrence are smaller than in the cold season. The rate of increase in temperature in the warm season is around 0.038 °C/yr, and that in the cold season is around 0.095 °C/yr. The growth rate of thin ice clouds in the warm season is around 0.15% per year, while that in the cold season is as high as 1% per year. The results suggest that the surface temperature change may be related to the occurrence frequency of thin ice clouds, with the notable increase in temperature during the cold season possibly being associated with a significant increase in the occurrence frequency of thin ice clouds. [ABSTRACT FROM AUTHOR]

The existing models for estimating cation exchange capacity (CEC) from easy‐to‐measure hygroscopic water content (θh) were based on a single water activity (aw) value rather than on the processes that govern soil water vapor adsorption for a distinct aw range. Here, we present a new CEC estimation model based on θh data of 119 soils with different clay mineralogy (i.e., illitic [IL], montmorillonitic [ML], and kaolinitic [KA] samples) and organic carbon (OC) contents for the aw range from 0.23 to 0.57 (Δθ0.23–0.57) and validate its performance. Based on the hypothesis that multilayer adsorption exhibits a higher correlation with CEC than monolayer adsorption and capillary condensation, the aw range from 0.23 to 0.57 was chosen with CEC calculated as CEC = k × Δθ0.23–0.57. The performance of the new model is compared to the Arthur (2017) model and the Torrent (2015) model, which considers a single θh value. The average proportionality coefficient (k) varied with the dominant clay mineralogy of the investigated soils. For soils dominated by 2:1 clay minerals (i.e., IL and ML), the new model showed a good estimation accuracy (Nash‐Sutcliffe model efficiency [E] ≥ 0.85; root mean squared error [RMSE] ≤ 4.18 cmol(+) kg−1). The new model performed better for IL and ML samples than for KA samples, and yielded more accurate CEC estimations than the Arthur model and Torrent model for soils with 2:1 clay minerals. For soil with high OC content (>23.2 g kg−1), the new model slightly underestimated CEC (E = 0.66; RMSE = 5.87). Core Ideas: A new model for estimating cation exchange capacity (CEC) from hygroscopic water content (θh) is introduced.The new model is established based on θh for a distinct water activity (aw) range.The new model had higher prediction accuracy than a single‐point θh CEC model. [ABSTRACT FROM AUTHOR]

Antifrosting surfaces are critical to the efficient and safe operation of infrastructure in cold and humid environments where deposition of frost (porous ice) is thermodynamically inevitable. Such infrastructure can include above-ground power cables and outdoor heat pumps. Here, we introduce a hybrid surface design that passively controls the diffusion of water vapor over a surface to sustain flat frost-free regions for long periods of time. We report more than 150 hours (~1 week) of frost prevention for a single hybrid unit cell, which is three orders of magnitude longer than reported frosting onset for other state-of-the-art techniques. We then demonstrate the potential for large-area frost prevention by scalable tessellation of unit cells and an intrinsic durability to scratches/cracks and physical contamination. [ABSTRACT FROM AUTHOR]

North China experienced an extreme precipitation event from July 29 to August 1, 2023 (i.e., the "23.7" event) causing severe floods, significant infrastructure damage and multiple fatalities. To enhance comprehension of the mechanism behind the extreme precipitation of the "23.7" event, water vapor transport paths and sources were determined, and water vapor contribution of each source was quantitatively evaluated based on Lagrangian methods. Results showed that the extreme precipitation of the "23.7" event was closely related to large‐scale water vapor transport and convergence from low‐latitude oceans. There were five main water vapor sources which corresponded to five transport pathways. Path 1 was derived from tropical West Pacific, containing the most trajectories (195), carrying the most water vapor (69.3%) and contributing the most to the extreme precipitation of the "23.7" event (45.7%). Path 2 was guided by the cross‐equatorial flow through South China Sea, contributing to 10.1% of the precipitation. Path 3 originating from eastern tropical Indian Ocean and Path 4 from the west source near the Caspian Sea contributed less to the precipitation. Last but not the least, water vapor evaporation from eastern China contributed more than 30% to the extreme precipitation, making this region another important water vapor source. [ABSTRACT FROM AUTHOR]

Global warming has strongly influenced the hydroclimatic cycle in arid regions. Here, we established the dendrochronology of spruce on the northern and southern slopes of the Qilian Mountains in the Hexi Corridor based on tree-ring width. The correlation response analysis showed that the radial growth of Picea crassifolia in the study area was limited mainly by precipitation from July of the previous year to June of the current year. Therefore, we developed July–June precipitation reconstructions for the northern and southern slopes of the Qilian Mountains, respectively, based on the ensemble model from the simple linear regression and K-nearest neighbor. Our new reconstructions displayed that during the past 257 years, the northern Qilian Mountains experienced 39 and 38 extreme wet and dry years, and 5 wet and 6 dry periods, respectively, and the southern Qilian Mountains experienced 61 and 51 extreme wet and dry years, and 6 wet and 6 dry periods, respectively. Spatial correlation using CRU precipitation and scPDSI grid data revealed that our reconstruction contains the precipitation signal that is representative of an extensive region of north-central China. The precipitation reconstruction includes major cyclicities of 2–5 years in the north and 7 years in the south, and they document drought/famine events in the late nineteenth century and during the 1920s–1930s. Water vapor from the Pacific Ocean is identified as the main factor responsible for high precipitation events in the study area, while low precipitation events were influenced by continental air masses. [ABSTRACT FROM AUTHOR]

Polyvinyl alcohol (PVA) and chitosan (CS) were mixed with purple tomato anthocyanins (PTA), and then nano zinc oxide (nano-ZnO) or calcium chloride (CaCl2) were added to prepare PVA/CS/PTA/ nano-ZnO (PCP-ZnO) or PVA/CS/PTA/CaCl2 (PCP-CaCl2) films. The effects of nano-ZnO and CaCl2 on the morphology, pH response, color stability, color reversibility, antibacterial activity, antioxidant activity, mechanical properties, water vapor permeability and UV absorption characteristics of films were studied. In addition, its application in intelligent packaging to monitor the freshness of pork was also studied. It was found that both nano-ZnO and CaCl2 can reduce the transmittance of the film in the visible light region, and the film with addition of nano-ZnO was more sensitive to pH. During the 14 day storage period, the film modified with CaCl2 exhibited better color stability. SEM images indicate that the addition of nano-ZnO or CaCl2 alters the microstructure of the film. The mechanical, antibacterial and antioxidant properties and also the application as freshness indicator of PCP-CaCl2 film were superior to those of PCP-ZnO film. Those indicated that the prepared PCP-CaCl2 film is a potential candidate for active and intelligent packaging applications. [ABSTRACT FROM AUTHOR]

Aiming at the near-clogging boundary condition of a certain type of transonic compressor rotor, a numerical simulation method is used to systematically study the influence of different droplet diameters on its performance under the condition of moisture content of 3%. The results show that humidifying the intake air of the transonic compressor near the blockage boundary can reduce the exhaust temperature, the mass flow rate, and the total pressure ratio. In the axial direction, the mass fraction of water vapor increases slowly and linearly under the large droplet condition, while the mass fraction of water vapor under the medium and the small droplet conditions presents a two-stage parabolic growth. The mass fraction of water vapor under the three conditions increases by 0.002, 0.0055, and 0.0072 from inlet to outlet, respectively. On the radial section with the axial span = 0.7, the difference in water vapor mass fraction between the shroud and the hub under the small droplet condition is 0.00329, and that under the medium and the large droplet condition are 46.81% and 27.96% of the small droplet condition. The research results can provide theoretical guidance for the analysis of droplet evaporation at different positions in compressor near-plugging conditions. [ABSTRACT FROM AUTHOR]

Non-destructive testing of cooling passages has attracted a considerable interest due to the critical rule of these segments in the performance and endurance of different parts. In this research, the performance of active infrared thermography in the non-destructive inspection of cooling passages located inside the metallic bases has been investigated. Water vapour was selected as an excitation fluid so as to create the thermal contrast. Specimen material, hole depth, hole diameter and injection pressure were selected as the input parameters effecting on the thermal contrast. The results obtained via statistical analysis revealed that the hole depth and injection pressure have the noticeable influence on the dimensionless output temperature recorded with thermal camera. A 50% decrease in dimensionless temperature contrast has been revealed when the hole depth has become four times. Besides, a similar increase in injection pressure, elevated the above-mentioned parameter almost 20%. In contrast, the parameters of specimen material and hole diameter specified no perceptible effects. Moreover, infrared thermography with water-vapour excitation proved proper capability in detection of 60% and 80% blockage located inside the holes. [ABSTRACT FROM AUTHOR]

Land-atmosphere coupling is a key factor for understanding the mean hydroclimatological conditions in South America. In this study, we analyzed how land-atmosphere coupling modulates the aridity conditions in the South American continent through experiments performed with a regional climate model. We assessed changes in precipitation (P), potential evaporation (PET), aridity index (ɸ = PET / P) and vapor pressure deficit (VPD) in experiments with and without soil moisture - atmosphere coupling. Additionally, we analyzed how air dry enthalpy (Hd), moist enthalpy (Hw) and total enthalpy (Ht) change between the coupled and uncoupled experiments, which help to identify patterns in aridity conditions. When analyzing ɸ, we found opposite responses in central-eastern Brazil and southeastern South America (SESA), the two main hotspots of land-atmosphere coupling. On the other hand, a widespread amplification of VPD is found. Both VPD and enthalpy are locally driven by changes in temperature and water vapor content and reflect wetter conditions in central-eastern Brazil and drier conditions in SESA. Changes in regional circulation, described in previous studies, increase moisture convergence in Brazil and help to explain the response of each individual metric when coupling is enabled. [ABSTRACT FROM AUTHOR]

The anthocyanin extracts (AE) from different sources were commonly used in preparing an indicator film to reflect food freshness, as AE contained rich anthocyanins which acted as the pH-sensitive ingredient. Therefore, this study aimed to compare the impact of AE sources (including rosella extract (RE), Lycium ruthenicum Murray (LE), and mulberry extracts (ME)) on the film properties and pH-sensitivity of konjac glucomannan/zein (KZ) composite film. Results showed that the three AEs had significantly different anthocyanin species and total contents, contributing to their different color changes in response to the pH changes. Some film property changes were not affected by the different AE, but mostly, different film property changing extents were observed, such as thickness, color, mechanical properties, hydrophilicity, antioxidant property, and water vapor permeability. This indicated that the hydrophilic plasticizing and void-filling effects of the anthocyanin were impacted by the anthocyanin structure. On the other hand, the impact of AE sources on the pH sensitivity and volatile ammonia sensitivity of the films was significantly different, mainly relating to both anthocyanin contents and composition. Finally, the KZ film with LE addition of 10% was suggested to be applied in the intelligent food packaging, as the addition of anthocyanin was relatively low and the film had both good pH sensitivity and film properties. [ABSTRACT FROM AUTHOR]

This study investigates the influence of airflow transport pathways on seasonal rainfall in the mountainous region of the Liupan Mountains (LM) during the rainy seasons from 2020 to 2022, utilizing observational data from seven ground gradient stations located on the eastern slopes, western slopes, and mountaintops combined with backward trajectory cluster analysis. The results indicate 1) that the LM's rainy season, characterized by overcast and rainy days, is mainly influenced by cold and moist airflows (CMAs) from the westerly direction and warm and moist airflows (WMAs) from a slightly southern direction. The precipitation amounts under four airflow transport paths are ranked from largest to smallest as follows: WMAs, CMAs, warm dry airflows (WDAs), and cold dry airflows (CDAs). 2) WMAs contribute significantly more to the intensity of regional precipitation than the other three types of airflows. During localized precipitation events, warm airflows have higher precipitation intensities at night than cold airflows, while the opposite is true during the afternoon. 3) During regional precipitation events, water vapor content is the primary influencing factor. Precipitation characteristics under humid airflows are mainly affected by high water vapor content, whereas during dry airflow precipitation, dynamic and thermodynamic factors have a more pronounced impact. 4) During localized precipitation events, the influence of dynamic and thermodynamic factors is more complex than during regional precipitation, with the precipitation characteristics of the four airflows closely related to their water vapor content, air temperature and humidity attributes, and orographic lifting. 5) Compared to regional precipitation, the influence of topography is more prominent in localized precipitation processes. [ABSTRACT FROM AUTHOR]

Bacterial cellulose (BC) and poly(vinyl alcohol) (PVA) stand out among biodegradable polymers to be inserted in the food packaging sector; these can have their properties enhanced when mixed with each other or with the addition of additives (antioxidants). This work initiated a study with BC/PVA blends incorporated with antioxidant food complex (EXT), using concentrations of 0, 1.08, 2.14, and 4.30 g/L of EXT in the fermentation medium. Blends produced were evaluated for water retention capacity, chemical structure, morphology, crystallinity, thermal stability, antioxidant activity, and permeability to water vapor. Pure and incorporated blends did not show a significant difference in water retention capacity and morphology. However, incorporated blends showed alteration in the infrared spectrum, decreased crystallinity, thermal stability, permeability to water vapor, and increased antioxidant activity. These results confirm the incorporation of EXT and make the blends promising against moisture and oxidative reactions in the food packaging sector. [ABSTRACT FROM AUTHOR]

Gas dehydration plays a critical role in gas refining processes due to the potential problems caused by the presence of water vapor. The inclusion of water vapor can lead to issues such as hydrate formation, pressure drop, and pipeline corrosion. In this research, a deep eutectic solvent (DES) absorbent was employed to absorb water vapor and subsequently, its absorption performance was compared with the absorption of tri-ethylene glycol (TEG) and lithium chloride, the most commonly used absorbents in water vapor separation processes. To do so, the influence of several effective parameters, including the inlet air flow rate, different ratios of choline chloride to urea (ChCl:Urea), the weight percentage of liquid water in the absorbent, and the viscosity of DES were investigated. The results demonstrated that DES is highly efficient for water vapor separation, outperforming both TEG and aqueous lithium chloride solutions. Moreover, increasing the inlet air flow rate was found to decrease absorption recovery due to reduced residence time. Additionally, a ChCl ratio of 1:2 yielded the highest absorption efficiency. [ABSTRACT FROM AUTHOR]

Flexible contact gasket is a significant component affecting the sealing performance of the refrigerator. However, few studies were conducted on the permeability characteristics of moist air through refrigerator gaskets. The purpose of this study is to explore the permeability characteristics including permeation paths size, flow type, modeling and temperature-humidity-pressure-structure effect. The characteristic scale of the interface of permeation paths is observed as 10−5 m in the free-state by atomic force microscope. The equation of Knudsen number and contact stress relation is established to judgment the flow types. By comparing the critical and simulated contact stresses, it is inferred that moist air simultaneously occurs slip, transition and free-molecular flows. A multi-scale coupling model of permeation rate is constructed to obtain the apparent permeability coefficient characterizing the permeability intensity. The air pressure difference affects the permeability characteristics in the form of direct driving force and changing the contact stress of the interfaces. Free-molecular flow mainly occurs under the negative pressure condition with inhalation coefficient of 2.26 × 10−5∼2.84 × 10−5 m2, while the slip flow mainly occurs under the positive pressure conditions with exhalation coefficient of 2.87 × 10−5∼4.65 × 10−5 m2. The essence of enhancing the sealing performance of structural improvement is to increase the contact stress and length of permeation path. By increasing the height, increasing the inclination angle, adding the auxiliary edges and adding an auxiliary airbag, the inhalation coefficient of moist air, the exhalation coefficient of moist air and the inhalation coefficient of water vapor are decreased by 54.82 %, 51.46 % and 66.04 %. [ABSTRACT FROM AUTHOR]

The current study focuses on the role of composition in the oxidation behavior of three commercial SiC fibers (Hi‐Nicalon Type S (HNS), Tyranno ZMI, and Tyranno SA) in a steam‐containing environment at 1000°C. Oxide scales that form on each of the three fiber types differ in morphology, microstructure, and composition. Differences are attributed to O and C contents, crystallinity, and minor alloying elements. Oxidation kinetics of the HNS fibers follow linear/parabolic (Deal–Grove) predictions over the entire range of exposure times (to 96 h). In the other fibers, deviations from the initial linear/parabolic trend occur when either the scale crystallizes in situ during oxidation (as on the ZMI fibers) or when structural changes internal to the fiber alter the chemical environment at the scale/fiber interface (on the SA fibers). Adaptations of the linear/parabolic oxidation model are used to rationalize the growth kinetics in the latter two cases. Collectively, the data and analyses indicate a two‐fold difference in permeabilities of crystalline and amorphous silica scales. Inferred interface reaction rates further suggest faster oxidation for fibers with greater amounts of amorphous Si–O–C. Moreover, crystalline scales are more prone to cracking, because of their higher viscosity at elevated temperatures and a deleterious phase transformation upon cooling. [ABSTRACT FROM AUTHOR]

Today, the production of edible and biodegradable films is one of the growing technologies in advanced societies. The use of these coatings is due to the replacement with polymeric materials and increasing the storage time of food. The main purpose of this study was to produce an edible film of soybeans protein isolate (3 to 7%), glycerol (1 to 3%) and Ziziphorpa capitata essential oil (0 to 1%) in order to create better taste and antimicrobial properties. After preparing the film, the physicochemical and mechanical properties of the film (thickness, density, solubility in water and acid, water vapor permeability, transparency, color changes, elongation percentage and tensile strength) were evaluated. After performing the above tests and investigating the effects of independent variables on the dependent variables, the oral film formulation was optimized. The results showed that the optimal formula can be achieved by using 3.54% soy protein isolate, 1% glycerol and 1% cactus essential oil at the level of desirability of 0.624. [ABSTRACT FROM AUTHOR]

Eggs are one of the low-cost sources of protein and are also perishable, so maintaining their internal quality during storage is particularly important. The current research was carried out with the aim of the effect of nanocomposite coating on the physicochemical changes of eggs during storage for 4 weeks. Uncoated eggs (control) and eggs treated with a two-component coating of polyvinyl alcohol/chitosan (PC), a three-component coating of polyvinyl alcohol/chitosan/montmorillonite (PCM) ), and PCM coatings incorporating concentrations of 2 and 4% garlic extract were evaluated in a total of 5 treatments and 3 replicates in a completely randomized design. The results showed that the concentration-dependent antimicrobial effect of garlic extract was higher against Staphylococcus aureus than Escherichia coli. The prepared films of active three-component PCM nanocomposite had greater thickness, higher tensile strength, and elasticity, lower solubility, less elongation at break, and lower water vapor permeability (p<0.05). At the end of 4 weeks of storage, the eggs coated with active three-component PCM nanocomposites had a thicker shell (0.400 mm) and a stronger shell (0.310 kg), causing less weight loss (About 4 %), Haugh unit (70.00) and yolk index (0.43) were higher and the lowest of total viable count bacteria (4.1 log cfu/ml). Therefore, using the three-component PCM nano-coating containing 4% garlic extract as a biodegradable packaging is possible to maintain the internal quality and eggshell and increase its storage time at ambient temperature. [ABSTRACT FROM AUTHOR]

Agricultural residues, specifically canola meal (CM) and oat hull (OH), have been innovatively utilized to develop biosorbents for sorbing water vapor from the air. These biomaterials are comprised of hydrophilic functional groups that effectively perform air dehydration. Air, being non-polar, was used as a model gas in this study to simulate gas dehydration. In the current research, these materials were formed into pellets to produce high-quality biosorbents with controlled size, shape, and enhanced moisture uptake capacity. CM (309.48 mg/g) and OH (233.07 mg/g) pellets had higher or comparable water sorption capacities than commercialized adsorbents used for drying gases. The mixed-order kinetic model described the sorption process well and identified both mass transfer and sorption on active site steps (R2 > 0.991 and χ2 < 16.0). Regarding the OH pellet, sorption on active sites was the predominant kinetic mechanism at the beginning, followed by intraparticle diffusion until equilibrium. However, sorption on CM pellets was delayed at 4.2 min at the initial stage, owing to the external mass transfer resistance; then, intraparticle diffusion controlled the process until equilibrium. Adding sodium lignosulfonate (LSNa) lowered the initial sorption rate but enhanced the water uptake and strength of pellets. The addition of LSNa resulted in a 25% and 14% increase in the water uptake capacity of oat hull and canola meal pellets, respectively; conversely, it also caused an increase in the delay time for sorption on CM pellets at the beginning of the process, extending it to 9.50 min. [ABSTRACT FROM AUTHOR]

This research systematically explores the use of corn stover (CS) with polypropylene (PP) and modified polypropylene (MPP) for sustainable food packaging. MPP is produced via melt mixing with dicumyl peroxide followed by maleic anhydride. The study aims to assess the potential of these biomass composites in eco‐friendly packaging applications. Our comprehensive evaluations include crystalline behavior, water absorption rate, contact angle, water vapor permeation coefficients, and oxygen transmission rates. Notably, at 20% CS content, the tensile strength of the MPP/CS composite material is about 120% higher than PP/CS composites. We also observed that CS significantly alters key properties of PP and MPP. The weight loss analysis of vegetables and water vapor transmission rate tests indicate that the MPP/CS composite film with 20% CS has the best effect on water vapor barrier and preservation of vegetables. Additionally, microbial growth analysis reveals that Escherichia coli and Staphylococcus aureus grow less abundantly on composites with lower CS contents, and MPP/CS composites show reduced microbial growth compared to PP/CS. This integrated study demonstrates the optimization of composite material performance through CS variables, revealing innovative potential for CS in enhancing PP and guiding the design of future sustainable packaging materials. Highlights: 20% CS in MPP/CS boosts tensile strength by 120% versus PP/CS composites.20% CS in MPP/CS gives optimal water vapor barrier and veggie preservation.MPP/CS reduces E. coli and S. aureus growth better than PP/CS, especially at low CS.MPP's functional group enhances CS compatibility, dispersion, structure, and crystallinity.Corn stover‐reinforced PP composites offer a sustainable, eco‐friendly packaging option. [ABSTRACT FROM AUTHOR]

Nanofibers act as carriers in systems containing functional materials produced via electrospinning method. By this way, it is possible to transport functional materials with polymer nanofibers, besides having a large surface area compared to their volume, the encapsulation process, which includes complex preparation processes, is eliminated here, and functional materials such as phase‐change materials (PCMs) can be conveniently integrated directly into the carrier material by electrospinning method. The resulting nanofiber membrane can also be used in combination with textile fabrics. This study aims to develop PCM containing nanofibrous membrane coated knitted fabric structures with heat regulation capabilities. Two types of PCMs, hexadecane and octadecane loaded into thermoplastic polyurethane (TPU) and cellulose acetate (CA) nanofibers, directly electrospun on cotton (CO), cotton/polyester (CO/PES), cotton/acrylic (CO/PAC) knitted fabrics for thermoregulation. These nanofiber‐coated fabrics were characterized by scanning electron microscopy (SEM) and differential scanning colorimetry (DSC), and their comfort properties were evaluated by water vapor and air permeability tests and compared with a commercial microcapsule impregnated fabric. According to DSC results, PCM incorporated CA nanofibers had better heat storage capacity than TPU nanofibers and microcapsule applied fabrics. Although PCM‐loaded CA nanofibers may not block airflow as effectively as TPU nanofibers, when a proper coating is achieved air permeability can be decreased to 21.70 L/m2/s, along with a heat storage capacity of 26.38 J/g and still having permeability to water vapor (%40). Highlights: Phase change materials were integrated directly to the carrier material by electrospinningPCM integrated nanofiber coating reduced air permeabilityPCM integrated nanofiber coating did not block water vapor permeabilityElectrspun cellulose acetate +PCM coating had better heat storage capacity [ABSTRACT FROM AUTHOR]

Several grottoes were excavated in Northwest China between the 5th and 13th centuries, and the most famous relics of these grottoes are wall paintings. The plaster layer is the most significant layer in grotto wall paintings, and its characteristics are related to deterioration, treatment measures, and restoration materials during the conservation process. However, studies investigating and analyzing ancient plasters in grotto wall paintings are scarce. In this study, a series of laboratory experiments was conducted on ancient plasters of four grottoes in Northwest China to reflect their physicochemical properties and microstructural characteristics. The results reveal that the plaster is composed of sedimentary soil from the riverbed or floodplain near the grottoes mixed with vegetal fibers. The sedimentary soils were mainly composed of fine-grained soil mixed with a certain concentration of sand (0‒41%). In the plaster production process, lime was not artificially added, and the internal structure of the plaster was formed by the agglomeration of sand-clay fibers. Capillary pores in the plaster are the main channels for salt migration and accumulation, and the accumulation of salt destroys the cementation between the soil particles, rendering the plaster loose and porous. Therefore, attention should be paid during daily maintenance to prevent further damage to wall paintings due to the migration and accumulation of salts caused by rainwater and water vapor. Sedimentary soils from nearby riverbeds or floodplains can be used in restoration work to obtain better compatibility with the original plaster. [ABSTRACT FROM AUTHOR]

Datong long-flame coal from China was pyrolysis with superheated water vapor at 300°C to 536°C. Chemical and physical changes of long flame coal, including composition, weight loss, pore fracture structure, density, and water absorption were tested, and the qualitative and quantitative relationships among these changes were analyzed. superheated water vapor pyrolysis removes moisture and volatile components from long flame coals and increases the fixed carbon content. After superheated water vapor pyrolysis, the O/C and H/C atomic ratios of long flame coal decreased due to the decomposition of oxygen-containing functional groups and chain aliphatic hydrocarbons. superheated water vapor pyrolysis increased the porosity of long flame coal by material removal and matrix fracture. Material removal occurs throughout the pyrolysis process but matrix fracture occurs only at the initial stage of the conversion of solid organic matter to oil and gas products. The expansion of pore fractures in long flame coal caused a significant decrease in apparent density and an increase in water absorption. Quantitative analysis revealed the forced water absorption of long flame coal was quadratically polynomial with respect to porosity. [ABSTRACT FROM AUTHOR]