• A systematic study of HT-PEMFC response to realistic methanol reformate compositions • Reformate gas compositions based on methanol steam reforming 0D process modeling. • Spatial mapping reveals impurity effects and how water vapor restores current distribution. • DRT analysis separates impurity effects on electrochemical processes. HT-PEMFCs are attractive for operation with methanol steam reforming systems, but their response to individual reformate components remains complex and spatially non-uniform. This study investigates the effects of carbon dioxide (CO₂), carbon monoxide (CO), and water vapor (H₂O) on HT-PEMFC performance under representative reformate compositions at 160°C and 170°C. Gas mixtures containing hydrogen with controlled CO₂ (10-30%) and CO (0.1-3%) concentrations were examined, while water vapor levels (1.0-2.5% RH) were selected based on reformer process modeling. A combined diagnostic approach using polarization curves, electrochemical impedance spectroscopy with distribution of relaxation times (DRT), and segmented current density mapping was applied. CO₂ induces performance losses primarily through hydrogen dilution and changes in fast anode processes, with higher overall degradation observed at 170°C due to increased ohmic resistance rather than kinetic. CO addition causes severe voltage losses, particularly at 160°C, driven by catalyst site blocking and strong kinetic limitations. Spatial analysis reveals that both CO₂ and CO preferentially suppress initially highly active MEA regions, leading to a more uniform-but overall reduced-current distribution. Introducing water vapor improves performance mainly by reducing the ohmic resistance associated with membrane hydration. This effect is spatially localized near the anode inlet and does not fully restore previously poisoned regions, indicating that hydration mitigates transport and conductivity losses but does not reverse kinetic deactivation. These findings highlight the importance of temperature-dependent ohmic effects and spatial diagnostics for realistic reformate-fed HT-PEMFC operation.

Effect of Water Vapor on the Oxidation Behavior of Ni-Based Superalloys Under the Coupling Conditions of Thermal Shock and Creep

This study evaluated the effect of water vapor generated by fresh-cut mango (Mangifera indica) on the release of β-carotene from β-cyclodextrin complexes (β-C:β-CD) under stored Modified Atmosphere Packaging (MAP) and to demonstrate β-carotene stabilization and passive-active packaging behavior under MAP conditions. Containers with fresh-cut mangoes, with and without MAP (4% O2, 6% CO2, 90% N2), were prepared for monitoring over 6 days at 4 °C. β-C:β-CD complexes were incorporated into the lids of containers. The physicochemical, relative humidity, antioxidant, erythroprotective, microbiological, and biofunctional qualities of freshly cut mangoes during storage were analyzed. Active metabolic respiration of plant tissue led to a progressive decrease in O2 and an increase in CO2 in sealed containers, a phenomenon intensified by cutting, high humidity, and the system's limited gas permeability. Application of MAP effectively modulated this microenvironment, reducing respiration rate, water loss, acidification, and the degradation of bioactive compounds. Compared to treatments without MAP, mangoes stored under modified atmosphere showed greater color stability, a slower rate of change in pH and titratable acidity, less loss of antioxidant activity and phenolic compounds, and significant preservation of erythroprotective capacity. Furthermore, MAP maintained microbial counts within the limits established by current regulations until the sixth day of storage. The encapsulation of β-C in β-CD effectively protected its bioactivity from oxidation, especially under MAP, although its release into the food matrix was limited, suggesting a predominantly passive behavior of the active packaging system. Overall, the results demonstrate that the combination of MAP constitutes a promising strategy for extending the shelf life and biofunctional stability of fresh-cut mangoes and β-C into the complex.

Competing effects of water vapor on Al₂O₃ scale growth and crack propagation in nickel-aluminide coatings at 950°C

Humidity-dependent radon retention in zeolite and non-zeolite sorbents for 225Ac production facilities.

The proposed work targets the characterization and removal of water vapour signatures from the ambient environment of terahertz spectroscopy and communication systems. A model of water-induced refraction and extinction is developed for this, with its single fitting parameter characterizing the combined effects from (unknown) propagation lengths and relative humidities in the environment. The model is used to suppress the water vapour characteristics from measured terahertz spectra, by 2.120 to 13.962 dB, with relative humidities spanning 25% to 62%. Ultimately, the process is found to be both fast, due to its use of a single fitting parameter, and effective, in mitigating the effects of water vapour over a broad terahertz spectrum.

Inhibitory effect of Ti and water vapor on high temperature oxidation of plasma cladding Inconel 718 coating

Effect of water vapor mixed into plasma gas on the preparation of ZnO transparent conductive thin films by atmospheric pressure low temperature plasma

Abstract Beijing's urbanization process may alter clouds, water vapor, and aerosols, which in turn influences surface incident solar radiation ( R s ). This study quantifies the urban–rural differences in R s , and explores the effects of clouds, water vapor, and aerosols on urbanization‐induced radiation effects. Ridge Regression Analysis was used as it effectively reduces the multicollinearities among factors. It is found that the urban–rural R s trend difference progressively increased, from −0.57 W·m −2 ·10 years −1 for 1960–1984 to −2.43 W·m −2 ·10 years −1 for 1985–1999, and then reversed to −0.50 W·m −2 ·10 years −1 for 2000–2013. The urbanization radiative effects were particularly pronounced for the first two periods, accounting for 40.97% and 42.24%, respectively, but reduced to 19.51% for 2000–2013. Overall, urban R s decreased faster than rural R s , which is mainly due to urban–rural difference in aerosol (26.8%) and water vapor (25.4%) for 1960–1984, aerosol (29.7%) and low cloud cover (28.4%) for 1985–1999, and total cloud cover (28.6%), low cloud cover (29.2%) and aerosol (26.3%) for 2000–2013 according to Ridge Regression Analysis. This study highlights a comprehensive understanding of the urbanization effect on the R s in megacities.

Mid-infrared European Extremely Large Telescope (ELT) Imager and Spectrograph (METIS), one of the first-generation instruments of the upcoming ELT, is designed toward the direct detection of exoplanets, using high-contrast imaging (HCI) techniques. However, it is well known that noncommon path aberrations (NCPA) limit HCI performance. In particular, quasi-static NCPA creates speckles that evolve on the same time scale as angular differential imaging (ADI) sequences, which are typically used to estimate and subtract the stellar speckle field. It is therefore crucial to model NCPA correctly during the instrument design phase to derive requirements on wavefront control algorithms that minimize their effects. We explore the chromatic beam wander caused by atmospheric refraction on METIS as a source of time-variable NCPA and its impact on HCI performance. We study the vortex coronagraph case, which is expected to set the requirements for NCPA correction. We propagate wavefronts through a model of the full METIS instrument in pupil tracking mode, taking into account the contribution of each optical element to phase aberrations in the presence of chromatic beam wander. We also model the associated amplitude aberrations that develop upon propagation. The beams are propagated within a 4-h interval, from which we extract a 1-h observing sequence close to the zenith as a representative ADI sequence. We show that the time-variable NCPA created by chromatic beam wander already reaches, and sometimes exceeds, the allocated NCPA budget within METIS, even though its effect is smaller than the effect of water vapor seeing at N-band. A closed-loop correction is needed to compensate for their effect, but even so, the HCI performance may be limited by the associated amplitude aberrations, which cannot be corrected within METIS.

Atmospheric ammonia, in both particulate and gaseousforms, hasmajor ecological, health, and economic impacts, making it essentialto understand its chemical processes. The reactions of ammonia andammonia complexed with nitric acid with hydroxyl radical and the oxidationof nitric acid by amidogen radical and ammonia by nitrate radical,both taking into account the effect of water vapor, have been investigatedusing quantum mechanical (QCISD and CCSD­(T)) calculations with the6-311+G­(2df,2p), aug-cc-pVTZ, and aug-cc-pVQZ and extrapolation tothe CBS basis sets. From a mechanistic point of view, the reactionof NH3 + OH follows a conventional hydrogen transfer mechanism,but for the rest of reactions considered, the proton coupled electrontransfer mechanism plays a key role. For the reaction of ammonia withhydroxyl radical we have computed a rate constant of 1.24 × 10–13 cm3·molecule–1·s–1 at 298 K, and the effect of water vaporis negligible. The calculated rate constant for the HNO3···NH3 + OH reaction is 6.50 × 10–16 cm3·molecule–1·s–1 at 298 K. and our results show that bothHNO3 and NH3 moieties can be oxidized. The effectof water vapor on the oxidation of nitric acid by an amidogen radicalis significant. We have computed a rate constant of 1.98 × 10–13 cm3·molecule–1·s–1, at 298 K and 100% of RH for the wholeHNO3 + NH2 + H2O reaction, whichis an 11% greater than the calculated value for the naked reaction.For the oxidation of ammonia by a nitrate radical, the effect of watervapor is huge. The calculated rate constant at 298 K and 100% of RHis 16 × 10–15 cm3·molecule–1·s–1 for the whole NH3 + NO3 + H2O reaction, that is, 751% greaterthan the value of the naked reaction at 298 K.

The effect of water vapor on the flammability of fluorinated refrigerants

A water-mist fire-suppression system suppresses fire through heat absorption during the evaporation of microdroplets (< 100 µm). Its performance is expected to improve owing to the suffocation effect of water vapor, given the high expansion rate of water. However, conventional systems have complex structures because high-pressure pumps are required to generate microdroplets. Therefore, we propose a water-mist system that uses ultrasonic waves to generate microdroplets. In addition, a scaled room corner test model is constructed to validate the fire-suppression performance of the proposed system. Experiments are conducted to analyze the fire-suppression performance and the effect of airtightness using this scaled model. The results can be used to propose assessment standards for fire-suppression performance and to establish fire scenarios for real-scale experiments. Obstruction of air supplied through the door increases the total fire and fire-suppression durations due to inadequate oxygen. Based on temperature distribution and fire-duration analyses, fire-suppression can be improved by applying ultrasonically generated water-mist. However, additional investigations are required to evaluate the effects of fire size, water-mist flow rate, and fuel mass loss.

Traditional high-temperature hydrothermal aging commonly inhibits selective catalytic reduction of NOx with ammonia (NH3-SCR) over zeolite catalysts, but a comprehensive understanding of the water vapor effect remains elusive. Herein, by combining the experiment and ab initio molecular dynamics (AIMD) simulations, a promoted mechanism for NOx conversion by water molecules at moderate temperatures is proposed over the Cu-SSZ-13 zeolite. Upon introducing 10 vol % H2O, NOx conversion is enhanced by approximately 20% at 400 °C, while under 5 vol %H2O at 180 °C, the conversion increased from 70% to 80%. Acting as a reactant in the SCR and a ligand for active Cu sites, water vapor drives CuOx redispersion to isolated framework Cu2+ species on the zeolite, creating Lewis acid sites for NH3 activation and avoiding NH3 overoxidation in the high temperature, while its dissociation produces bridge and terminal hydroxyl groups for NH3 adsorption. Meanwhile, preferential coordination of H2O molecules at Cu sites triggers a shift in hydroxyl reactivity, from free H atom attacks on the coordinated hydroxyl in Cu(H2O)(OH) to proton transfer between the NNH+ transition state and free hydroxyl groups. This transformation effectively avoids deep energy wells and decreases the overall energy barrier. This research elucidates a distinct water-mediated mechanism over a Cu-exchanged zeolite for NH3-SCR.

Currently, exploratory thermodynamic studies of the PVT reservoir fluids properties to assess the effect of condensate water on reserves estimation, design and development of the fields are carried out on Russian National and international oil companies. Such PVT ratios settings allow a wide range of pressures and temperatures to be used to study phase transitions of hydrocarbon systems. Conducted experimental studies of gas condensate systems showed a negative effect of formation water on the amount of condensate extraction during development. The studies were conducted on recombined samples of gas separation, formation water and saturated condensate taken from the wells during the pilot development of the Srednetyungskoe field in Western Yakutia. Wherein, a pattern was found of increasing the loss of high molecular hydrocarbons at the stage of the onset of condensation with increasing water vapor content in the gas condensate system. As a result of studies of the dependence of hydrocarbon losses during the increasing in the water vapor content in the system, certain parameters are the initial ones when calculating the reserves of hydrocarbon and non-hydrocarbon components in natural gas, the development of designing and field development. The aim of thermodynamic investigations was to determine the effect of formation and condensation water vapors on the condensate recovery rate during the isothermal condensation process, which manifests itself when the pressure decreases in the oil and gas condensate field.

Since the discovery of carbon nanotubes (CNTs), extensive and comprehensive research has been conducted in many areas of materials science. Due to their structural and chemical properties, they can be an important part of electronic devices and structural materials that surround us. In this work, we focused on the preparation and basic analysis of vertically aligned CNTs. An aluminum oxide carrier layer and bimetallic iron-cobalt catalyst layers of different compositions were fabricated on the surface of a silicon substrate using a pulsed laser deposition method. Then, vertically aligned CNTs were grown using a catalytic chemical vapor deposition method based on the thermal decomposition of ethylene. During the experiments, the effect of water vapor and hydrogen gas was investigated on the structure of as-prepared carbon nanotubes. CNT forest samples were characterized by scanning electron microscopy and Raman spectroscopy. One of the most important findings of this research is that the presence of hydrogen gas in the CCVD system is essential, but high-quality vertically aligned CNTs can be produced on silicon substrates even without water vapor.

Purpose. To determine the feasibility and prospects for the development of processes and means of carbonization of biomass fuel briquettes to increase the efficiency of heat supply from briquette products. Methods. Analytical review and systematic analysis of the development of technological processes and technical means for briquetting plant raw materials for thermal needs. Comparative analysis of the elastic-relaxation properties of polymer components of plant materials during carbonization of briquettes into bio-char. Modeling of thermally stabilized pyrolysis of fuel briquettes from biomass at a temperature of 380–450 ºС. Results. An analysis of existing presses for briquetting plant raw materials was conducted. A type of Pini-Kay briquettes favorable for carbonization was determined, which are obtained on screw-type presses-extruders. The features of relaxation transitions of polymer components of biomass at the stages of obtaining bio-coal briquettes were analyzed. It was found that the process of isothermal carbonization is based on the phenomenon of exothermic decomposition of biomass and a combination of thermally stabilized pyrolysis using a highly inertial pyrolysis reactor. As a result, a technology for obtaining bio-coal briquettes is provided. Relaxation properties in the creation of carbonization biofuel were studied on model samples of plant raw materials. Types of second-generation solid biofuels – bio-coal (carbonized) briquettes were predicted. Their main properties, calorific value and potential areas of application were determined. Conclusions 1. At present, a promising innovative method for the utilization of wood and agricultural waste is the production of bio-coal (carbonized) briquettes. The innovative technology for obtaining such fuel briquettes is based on changing the relaxation state of the polymer components of biomass (lignin, cellulose and hemicellulose). It allows converting plant waste into a carbonized state of briquettes without the use of binders at rational energy and capital costs. 2. The carbonization process is carried out in an isothermal regenerative pyrolysis reactor in a controlled steam-gas environment. Therefore, heterogeneity is realized in the briquettes under the influence of temperature and the plasticizing effect of water vapor, due to which the process proceeds in conditions of an open capillary-porous structure, which is fixed in the carbonized material of the fuel briquettes. 3. During the exothermic decomposition of biomass, a significant amount of heat is released, which is sufficient to complete the carbonization process without external heating, provided that heat losses to the environment are excluded. In the final period of pyrolysis at temperatures of 380–450 ºС, a slight formation of liquid products, mainly heavy tar, occurs. The gases released consist of СО2, CO and hydrocarbons. As a result, bio-coal briquettes with a modified structure and a density of up to 800 kg/m3 are obtained, which provides high thermal conductivity. Keywords: plant raw materials, processes, briquettes, carbonization, pyrolysis reactor, isotherm, regeneration, pyrolysis gases, bio-char.

Abstract Methane is the third most significant anthropogenic driver of climate change after carbon dioxide and aerosols, contributing about one-fourth of carbon dioxide’s effective radiative forcing in the industrial era. Given the role of methane in observed and future climate changes, this study compares the slow climate responses to carbon dioxide (CO2) and methane (CH4) radiative forcings by estimating individual climate feedbacks using radiative kernels. We use the National Center for Atmospheric Research (NCAR) Community Atmosphere Model, version 5 (CAM5), in two configurations (prescribed sea surface temperature and slab ocean) to estimate radiative forcing and climate response, respectively. These experiments show that for comparable radiative forcing, methane forcing’s efficacy in the 10xCH4 experiment (0.90) is smaller than the efficacy of 1.35xCO2 (unity), consistent with previous studies. This lower efficacy of the slow response for CH4 owing to its more negative feedback (−1.08 W m−2 K−1) compared to CO2 (−0.97 W m−2 K−1) is attributed to differences in lapse rate, water vapor, shortwave cloud, and albedo feedbacks. Despite the broadly similar meridional distributions of radiative forcing, methane’s larger longwave and shortwave forcing in tropical latitudes gives rise to significant differences in lapse rate and cloud feedbacks, resulting in smaller climate sensitivity than CO2 forcing. CH4 also has a smaller albedo feedback, owing to its atmospheric absorption of shortwave radiation. Significance Statement In this study, we compare the climate responses to increases in two different greenhouse gases, carbon dioxide (CO2) and methane (CH4), and show how differences in their meridional patterns of radiative forcing affect the magnitude of global-mean surface warming. Using a climate model and the forcing-feedback framework, we show that CH4 produces smaller global-mean surface warming than CO2 for similar magnitudes of global-mean radiative forcing, mainly due to larger warming caused by the net effect of temperature, water vapor, cloud, and surface albedo feedbacks in the case of CO2 forcing compared to the CH4 case. Consequently, although the climate response from the same magnitude of radiative forcing is similar to within 10%, there are systematic differences in climate feedbacks and warming patterns between forcing due to CH4 and CO2.

ABSTRACT This study propounds a simple physical model for quantifying the combined radiative forcing effects of atmospheric carbon dioxide (CO2) and water vapour (WV) in terms of the temporal changes of CO2, WV and surface air temperature (T) within the troposphere. Using open-source satellite-derived data, this work presents for the first time the yearly maps of radiative forcing (F) over a large region of tropical India, and identifies three distinguished contributing agents to F, namely the radiative component (F T) due to temperature-related evaporation, the radiative component (F C) due to CO2-induced change in evaporation through temperature and the incremental change of T. The ratio of F C to F T is defined as feedback factor (f) initiated by CO2 and executed by WV. Interestingly, the F T maps for years 2003-2023 exhibit a periodic change having similarities with both the solar cycle and the terrestrial climate pattern of El Nino-Southern Oscillation. The F C maps, hence the F maps are plotted for years 2016-2021 due to the limited availability of high spatial resolution CO2 data. Each of the above three components involved in the net radiative forcing has its own individual influence and the vigour of any one may mask the effect of the others.

Abstract. Meteorological satellite data have been extensively utilized in global numerical weather prediction systems and have a positive impact to improve forecast accuracy. In order to correctly assimilate satellite radiance observations in data assimilation systems, the systematic observation biases must be corrected to conform to a Gaussian normal distribution with a mean of 0. By selecting appropriate air-mass predictors through correlation assessment, a two-step bias correction scheme (namely the scan-angle bias correction and the air-mass bias correction) is established in this paper based on radiance observations of FY-3E/ HIRAS-II from 1 to 31 January 2023. The results indicate that FY-3E/HIRAS-II O−B (observation-simulation) bias exhibits scanning angle bias dependence from nadir to limb field of view. Statistics have found that this scanning angle bias does not depend on latitude band. After scan-angle bias correction using statistical scan-angle correction coefficients, the dependence of the O−B biases on the scan angle can be eliminated. The second step is to perform air-mass correction. Our correction scheme is compared with the air-mass bias correction scheme in NCEP-GSI. Although the scan angle influence is also considered in NECP-GSI scheme, it does not account for the water vapor effect in the atmosphere. Consequently, the correction effect is not good for channels with lower peak height of weighting function, resulting in a slightly residual positive bias after correction. The combination of air-mass predictors (model surface skin temperature, model total column water vapor, thickness of 1000–300 hPa, and thickness of 200–50 hPa) selected through importance assessment in this study effectively eliminates the air-mass biases. The systematic biases between observed brightness temperature and background simulated brightness temperature from background atmospheric field for all HIRAS-II channels significantly decrease after bias correction, and the bias distribution essentially follows a Gaussian normal distribution with a mean of 0. The FY-3E/HIRAS-II data assimilation experiments show that the selected air-mass predictors (EXP-2 scheme) is the most effective among the four experiments. The mean O−B and O−A in all channels are the smallest after bias correction. Compared with the independent ERA5 objective analysis fields, the EXP-2 scheme has a significant improvement for the temperature analysis at upper air and near surface. The water vapor profiles of the EXP-2 scheme are the closest to ERA5 at almost all height levels.