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Eruptive dynamics is influenced by gas escape from the ascending magma. Gas pathways form in the magma via bubble coalescence, leading to gas channeling. Magmatic crystals play a key role in gas channel formation. This work constrains experimentally decompression‐induced coalescence in high‐crystallinity silicic magmas without external deformation, focusing on low gas content and bimodal crystal size (microlites and phenocrysts). All percolating samples have permeabilities of 10−14 m2 at bulk porosities of 7–10 vol% and bulk crystallinities up to 75 vol%. Our results demonstrate the possibility of coalescence‐related outgassing at high pressure (120–350 MPa) and without external strain, which corresponds to magma stagnating deep in a volcanic conduit. Channeling at such low gas content implies that bimodal crystallinity favors effusive over explosive volcanic behavior. It may also be the missing physical mechanism explaining gas transfer across magmatic systems despite high melt viscosity and low or absent magma extrusion. Plain Language Summary: The way volcanoes erupt is mainly controlled by the ability of gases to escape from the magma (outgassing). An efficient way to outgas is to connect bubbles together (coalescence) up to the point where channels form in the magma (channeling) in which gas can circulate toward the surface. We investigate experimentally how coalescence and channeling happen in immobile, crystal‐rich viscous magma in conditions (pressure and temperature) similar to those found in deep volcanic conduit, where only a small amount of gas (<10%) is present. Our experiments demonstrate that bubble connections are possible thanks to a large amount of crystals on which bubbles can lean, deform, and join each other. That gas can escape from magma at depth could favor effusive eruption over volcanic explosions and even bring new insights on degassing in immobile magma. Key Points: Gas permeability in silicic magma is possible with gas volumes below 10% thanks to high crystallinityOutgassing at low gas content can happen without external deformation nor fracturation of the magmaVolcanic outgassing in stagnant magmas is explained by deep conduit bubble channeling that may be a key mechanism in eruptive transition [ABSTRACT FROM AUTHOR]

Crystal-rich silicic lavas commonly erupt from hazardous lava dome-forming volcanoes, characterized by both effusive and explosive eruptions. Magma explosivity is inherently dependent on its ability to store pressurized gas, which can be released through permeable pathways like fractures or connected bubbles, yet the role crystals play in regulating gas escape is poorly constrained in crystal-rich systems. We explored the gas storage capacity and outgassing efficiency of crystal-rich magmas through experimental vesiculation of hydrous dacite samples containing crystal volume fractions ( ϕ x ) between 0.5 and 0.8. The maximum unconnected gas volume (isolated porosity) decreases exponentially with increasing crystallinity. We quantify the relative outgassing efficiency as a function of ϕ x using changes in isolated melt porosity during open-system degassing (outgassing). Mean isolated porosity, for ϕ x = 0.5, increases from ~ 0.33 at the start of outgassing to ~ 0.67 by the end, doubling its trapped bubbles. For ϕ x = 0.7, isolated porosity increases from ~ 0.1 to ~ 0.2, implying gas retention and outgassing efficiency are strongly dependent on crystallinity. Outgassing occurs rapidly via fracturing at porosities < 0.1 when ϕ x ≥ 0.7. Fracturing and bubble coalescence are both inefficient outgassing mechanisms at ϕ x = 0.5 due to viscoelastoplastic deformation, which leads to an increase of isolated porosity. Between ϕ x of 0.5 and 0.7, samples sustained a three-fold difference in isolated porosity, implying that gas retention and eruptive behavior of crystal-rich magmas may be controlled by the onset and efficacy of crack-dominated outgassing and can be modulated by relatively small changes in crystallinity. [ABSTRACT FROM AUTHOR]

Inflatable gossamer space structures require structural rigidity after partial or complete out-gassing of the inflation gases. The current study focuses on the rigidity generation in a fully deployed, out-gassed Kapton laminated conical boom. A novel approach is applied to produce out-of-plane structural stiffness in the gossamer structure using the shape memory alloy (SMA) wires embedded between Kapton laminate membranes. The finite element analysis is performed to find the generated stiffness in the system and validated with the experimental results. To this end, an experimental set-up is developed to provide a stable and uniform thermal environment with the inflation facility. Additionally, different measuring devices are also employed in the test set-up to note the readings of pressure, temperature, and displacement sensors. Moreover, the Kapton and SMA material properties are found experimentally, and their material models are validated with published studies. Furthermore, constitutive equations of the SMA-Kapton composite are also included in the study. After that, a parametric study is done to know the effect of design and material parameters on the boom's stiffness. [ABSTRACT FROM AUTHOR]

The Sturtian "Snowball Earth" glaciation (ca. 717-661 Ma) is regarded as the most extreme interval of icehouse climate in Earth's history. The exact trigger and sustention mechanisms for this long-lived global glaciation remain obscure. The most widely debated causes are silicate weathering of the ca. 718 Ma Franklin large igneous province (LIP) and changes in the length and degassing of continental arcs. A new generation of two independent Neoproterozoic full-plate tectonic models now allows us to quantify the role of tectonics in initiating and sustaining the Sturtian glaciation. We find that continental arc length remains relatively constant from 850 Ma until the end of the glaciation in both models and is unlikely to play a role. The two plate motion models diverge in their predictions of the timing and progression of Rodinia break-up, ocean-basin age, ocean-basement depth, sea-level evolution, and mid-ocean ridge (MOR) carbon outflux. One model predicts MOR outflux and ocean basin volume-driven sea level lower than during the Late Cenozoic glaciation, while the other predicts outgassing and sea level exceeding those of the Late Cretaceous hothouse climate. The second model would preclude a major glaciation, while the first model implies that the trigger for the Sturtian glaciation could have been a combination of an extremely low MOR outflux (~9 Mt C/yr) and Franklin LIP weathering. Such minimal outflux could have maintained an icehouse state for 57 m.y. when silicate weathering was markedly reduced, with a gradual build-up of MOR CO2 in the atmosphere paired with terrestrial volcanism leading to its termination. [ABSTRACT FROM AUTHOR]

While reactor wall preconditioning was previously shown to influence the yield in chemical vapor deposition (CVD), especially for the growth of carbon nanotubes (CNTs), it was limited to studying accumulating carbonaceous deposits over a number of runs. However, the effects of temperature and duration as the reactor walls are exposed to hot humidity for extended periods between growth runs were not previously studied systematically. Here, we combine experimental measurements with a mathematical model to elucidate how the thermochemical history of reactor walls impacts growth yield, especially knowing that only a specific range of humidity promotes growth. Importantly, we demonstrate a one-order-of-magnitude higher CNT yield by increasing the interim, i.e., the time between runs. We explain the results based on previously unexplored process sensitivity to trace amounts of oxygen-containing species in the reactor. In particular, we model the effect of small amounts of water vapor being desorbed from reactor walls during growth. Our results reveal the outgassing dynamics and show the underlying mechanism of generating growth-promoting molecules. By installing a humidity sensor in our custom-designed multizone rapid thermal CVD reactor, we are able to uniquely correlate the amount of moisture within the reactor to real-time measurements of growth kinetics, as well as ex situ characterization of CNT alignment and atomic defects. Our findings enable a scientifically grounded approach toward both boosting growth yield and improving its consistency by reducing run-to-run variations. Accordingly, engineered dynamics recipes with added preprocessing steps can be envisioned to leverage this phenomenon for improving manufacturing process scalability and robustness. [ABSTRACT FROM AUTHOR]

Investigations into surface flashover characteristics and underlying mechanisms in the range from atmospheric to near vacuum pressure are significant for developing high-power equipment based on the application of gases used for flashover prevention. In this work, polyetherimide (PEI) films with controllable outgassing properties were prepared. Then, the gas-related factors, namely, gas pressure, the type of gases, and outgassing were clarified by investigating the DC surface flashover of films in a wide pressure range (10−4–105 Pa) in different gas atmospheres. In all conditions, the variation of flashover voltage was found to be divided into three regions with pressure increasing, while its deeper reason is that the number density of molecules of the gas layer is affected by outgassing and ambient gas pressure, which affects the collision of electrons. In region I, the surface flashover voltage is closely related to outgassing and shows the highest value. In region II, the surface flashover is jointly affected by outgassing and ambient gas, along with a rapid decrease of flashover voltage with increasing pressure. In region III, the surface flashover is dominated by ambient gas, and the surface flashover voltage shows a U-shaped curve with increasing pressure. Transition points of the three regions shift significantly with the change of outgassing properties. In region I, the desorption of adsorbed gas has little effect on the surface flashover voltage, while the escape of dissolved gas dominates. Finally, a model of the diverse effects of gases on surface flashover in a wide pressure range was established. [ABSTRACT FROM AUTHOR]

The biogeochemical transformation of dissolved carbon in tidal beaches affects the coastal carbon cycle and budget. Yet, the influence of groundwater flow on the behavior of dissolved carbon and CO 2 flux across the different interfaces in these dynamic beach systems remains poorly understood, especially in deep beach aquifers. In this study, we investigated the biogeochemical reactions and origins of dissolved carbon and quantitatively evaluated CO 2 outgassing driven by submarine groundwater discharge (SGD) in a high permeability beach aquifer (9–13 m depth) located in the South China Sea shelf. Results revealed that both dissolved inorganic carbon (DIC) and total alkalinity (TA) exhibited non-conservative additions across the salinity gradient. The excess DIC and TA most likely resulted from organic carbon decomposition in the brackish and saline zones. Aerobic respiration (upper saline plume zone), anaerobic reactions, and tidal mixing were identified as the dominant processes controlling DIC and TA dynamics. The mean CO 2 outgassing flux across the beach sediment-air interface was estimated to be 1.05 g m−2 d−1, significantly higher than the CO 2 flux across the sea-air interface. The outgassing pattern of groundwater CO 2 from beach aquifer appeared to be driven by tidal pumping. Considering the combined effects of SGD-derived dissolved carbon and nutrients, we suggest that SGD yielded a net CO 2 flux, contributing to 45 % of the CO 2 flux across the sea-air interface. SGD directly and indirectly delivered substantial CO 2 from the beach aquifer to the atmosphere, approximately (4.89–9.21) × 103 tons of CO 2 per year along the 76.2 km long sandy coast. These findings demonstrate that intertidal beach aquifers, as active biogeochemical reactors have the strong potential to intensify CO 2 emissions to the atmosphere through both beach sediment-air and sea-air interfaces. This study provides a better understanding of the links between carbon biogeochemical cycles and hydrologic processes in the coastal zones. [ABSTRACT FROM AUTHOR]

The high‐entropy approach is applied to monoclinic Prussian White (PW) Na‐ion cathodes to address the issue of unfavorable multilevel phase transitions upon electrochemical cycling, leading to poor stability and capacity decay. A series of Mn‐based samples with up to six metal species sharing the N‐coordinated positions was synthesized. The material of composition Na1.65Mn0.4Fe0.12Ni0.12Cu0.12Co0.12Cd0.12[Fe(CN)6]0.92□0.08 ⋅ 1.09H2O was found to exhibit superior cyclability over medium/low‐entropy and conventional single‐metal PWs. We also report, to our knowledge for the first time, that a high‐symmetry crystal structure may be advantageous for high‐entropy PWs during battery operation. Computational comparisons of the formation enthalpy demonstrate that the compositionally less complex materials are prone to phase transitions, which negatively affect cycling performance. Based on data from complementary characterization techniques, an intrinsic mechanism for the stability improvement of the disordered PW structure upon Na+ insertion/extraction is proposed, namely the dual effect of suppression of phase transitions and mitigation of gas evolution. [ABSTRACT FROM AUTHOR]

The high‐entropy approach is applied to monoclinic Prussian White (PW) Na‐ion cathodes to address the issue of unfavorable multilevel phase transitions upon electrochemical cycling, leading to poor stability and capacity decay. A series of Mn‐based samples with up to six metal species sharing the N‐coordinated positions was synthesized. The material of composition Na1.65Mn0.4Fe0.12Ni0.12Cu0.12Co0.12Cd0.12[Fe(CN)6]0.92□0.08 ⋅ 1.09H2O was found to exhibit superior cyclability over medium/low‐entropy and conventional single‐metal PWs. We also report, to our knowledge for the first time, that a high‐symmetry crystal structure may be advantageous for high‐entropy PWs during battery operation. Computational comparisons of the formation enthalpy demonstrate that the compositionally less complex materials are prone to phase transitions, which negatively affect cycling performance. Based on data from complementary characterization techniques, an intrinsic mechanism for the stability improvement of the disordered PW structure upon Na+ insertion/extraction is proposed, namely the dual effect of suppression of phase transitions and mitigation of gas evolution. [ABSTRACT FROM AUTHOR]

Fluid inclusion microthermometry on olivines, clinopyroxenes, and amphiboles was used during a volcanic eruption, in combination with real-time seismic data and rapid petrographic observations, for petrological monitoring purposes. By applying this approach to the study of 18 volcanic samples collected during the eruption of Tajogaite volcano on La Palma Island (Canary Islands) in 2021, changes in the magma system were identified over time and space. Magma batches with distinct petrographic and geochemical characteristics emerged from source zones whose depth progressively increased from 27 to 31 kilometers. The rise of magma of deeper origin is attested by fluid inclusions made of N2 and CO, markers of mantle outgassing. Magma accumulation occurred over different durations at depths of 22 to 27 and 4 to 16 kilometers. Time-integrated magma ascent velocities (including ponding times) were estimated at between 0.01 and 0.1 meters per second. This method is cost-effective and quickly identifies changes in the magma system during an eruption, enhancing petrological monitoring procedures. [ABSTRACT FROM AUTHOR]

Over previous campaigns, an intense experimental program on advanced tokamak (AT) scenarios, has been carried out at the ASDEX Upgrade tokamak with full-tungsten wall. These discharges have been executed shortly after the boronization of the first wall to reduce the density and the impurity influx. The confinement level of such AT discharges was found to vary considerably, even when discharges with similar, if not identical, engineering parameters were carried out. This work investigates the causes of such confinement variations. Among all plasma quantities analyzed, confinement quality of AT scenarios correlates best with divertor neutral pressure, highlighting the key role of edge and scrape-off layer physics in determining global plasma confinement. In particular, it is found that the main cause of confinement degradation is the reduction of pedestal stability, which is in turn caused by the outward shift of the maximum density gradient position typically observed when the divertor neutral pressure increases. Owing to the low density of AT discharges under analysis, the movement of the maximum density gradient position can be caused entirely by changes in deuterium outgassing from the wall, which is strongly influenced by the boron layer deposited on the plasma-facing components and by the deuterium wall inventory. Finally, the predictive capability of confinement quality with the integrated model IMEP [Luda et al., Nucl. Fusion 60, 036023 (2020)] is tested on these discharges and shows promising results. [ABSTRACT FROM AUTHOR]

Ultrahigh‐strength steel (UHSS) structures are plated with Zn–Ni coatings because of their excellent corrosion resistance properties, but the plating process is accompanied by the production of hydrogen. The presence of hydrogen in steel results in hydrogen embrittlement. Hence, during the production of UHSS parts, dedicated outgassing steps are employed to remove the diffusible hydrogen from the steel. In a production environment, the real effect of the outgassing process and the outgassing efficiency is unknown for parts coated with Zn–Ni. Hence, a finite element model is developed to capture the evolution of the hydrogen concentration profile in coated UHSS parts during outgassing to study the influence of coating morphology and microstructural features of steel. In order to develop the geometry of the model, scanning electron microscope images are analyzed to understand the microstructure and morphology of the coating. Numerical samples are generated by combining different coating morphologies with steel substrates of varying microstructural features to attain a series of samples with varying features. The results of the outgassing simulations clearly demonstrate the major role of the coating morphology on the hydrogen flux. [ABSTRACT FROM AUTHOR]

The influences of titanium (Ti) doping on the gas retention capacity and photo-induced outgassing behavior of hollow glass microspheres (HGMs) were investigated. It was found that the addition of Ti4+ did not significantly impact the permeability of HGMs, which exhibited a pressure half-life over 100 days. The K p of Ti3+-doped HGMs was found to be 3–8 times higher than that of Ti4+-doped HGMs, where oxygen vacancies and phase interfaces in the glass shell act as gas diffusion passages. Fortunately, these defects can be eliminated by heat treatment at 600 °C to improve the gas retention capacity. Moreover, photo-induced outgassing was observed in Ti3+-doped HGMs due to the absorption of light in the range of 400–2400 nm, while no absorption or response to illumination was observed in Ti4+-doped HGMs. Notably, the photo-induced outgassing was found to be controllable and repeatable without attenuation of response rate or intensity over four trials. photo-induced gas release in Ti3+ doped hollow glass microsphere. [Display omitted] • Ti3+-doped spheres are photoactive during outgassing, while Ti4+-doped are not. • The photo-induced outgassing of spheres is repeatable and controllable. • The gas retention capacity of Ti3+-doped spheres is improved by annealing. • Ti4+-doped spheres exhibit low permeability, benefitting hydrogen storage. [ABSTRACT FROM AUTHOR]

The degassing of Allende carbonaceous chondrite (CV3 type) was studied using a setup specially designed for this purpose. The experiments involved stepwise heating (without gas accumulation) and isothermal annealing of meteorite samples with the composition of released gases determined through gas chromatography methods in the temperature range from 200 to 800°C. To account for sorbed water, degassing at 50 and 110°C was additionally analyzed. The Raman and IR spectra of both the primary Allende substance and the substance after its annealing at three temperatures (200, 500, and 800°C) were obtained. These spectra were used to trace the thermal transformation of the substance of the meteorite's parent body and estimate the maximum temperature of metamorphism. The results were compared with the degassing of the Murchison carbonaceous chondrite of another type (CM2). [ABSTRACT FROM AUTHOR]

LiNiO2‐based high‐nickel layered oxide cathodes are regarded as promising cathode materials for high‐energy‐density automotive lithium batteries. Most of the attention thus far has been paid towards addressing their surface and structural instability issues brought by the increase of Ni content (>90 %) with an aim to enhance the cycle stability. However, the poor safety performance remains an intractable problem for their commercialization in the market, yet it has not received appropriate attention. In this review, we focus on the gas generation and thermal degradation behaviors of high‐Ni cathodes, which are critical factors in determining their overall safety performance. A comprehensive overview of the mechanisms of outgassing and thermal runaway reactions is presented and analyzed from a chemistry perspective. Finally, we discuss the challenges and the insights into developing robust, safe high‐Ni cathodes. [ABSTRACT FROM AUTHOR]

LiNiO2‐based high‐nickel layered oxide cathodes are regarded as promising cathode materials for high‐energy‐density automotive lithium batteries. Most of the attention thus far has been paid towards addressing their surface and structural instability issues brought by the increase of Ni content (>90 %) with an aim to enhance the cycle stability. However, the poor safety performance remains an intractable problem for their commercialization in the market, yet it has not received appropriate attention. In this review, we focus on the gas generation and thermal degradation behaviors of high‐Ni cathodes, which are critical factors in determining their overall safety performance. A comprehensive overview of the mechanisms of outgassing and thermal runaway reactions is presented and analyzed from a chemistry perspective. Finally, we discuss the challenges and the insights into developing robust, safe high‐Ni cathodes. [ABSTRACT FROM AUTHOR]

Depositional profiles often feature sorted layers with stratified porosity and water retention, but the vertical partitioning of CO2 production and transfer remain unclear. In this study, fine soil and coarse sand were refilled to form three layering patterns: Layer-Mix (soil and sand well-mixed), Layer-Thin (8 thin layers interlaid), and Layer-Thick (4 thick layers interlaid). Three doses of 13C-labelled glucose were respectively added to the top, middle, and bottom. The results show that the Layer-Thin and Layer-Thick cumulatively released 62% and 67% less CO2 than the Layer-Mix. The 13C-CO2 contributed 14.1~60.3% to the total CO2 released from the Layer-Mix, but was only responsible for 7.3~48.8% of that from the Layer-Thin and 7.0~37.0% of that from the Layer-Thick. The peaks of δ13C-CO2 of the two interlaid columns were lowered and lagged by 1~2 days, but the δ13C residue remaining in the soil were on average 3~6‰ more negative than that of the Layer-Mix. The 13C-CO2 contributed more to the total CO2 when the glucose was added at the top, but the δ13C-soil was 3‰ more negative when added at the bottom. Overall, the lagged outgassing and lower share of 13C-CO2 from the two interlaid columns did not match with the more negative 13C residue remaining in the soil. Such inconsistency collectively highlights that the interlaid layers did not inhibit the decomposition of 13C-labelled glucose (i.e., potentially abundant CO2 produced), but the low diffusivity of the fine layers significantly impeded CO2 transfer through the heterogeneously structured soil profile. [ABSTRACT FROM AUTHOR]

Breadcrust bombs formed during Vulcanian eruptions are assumed to originate from the shallow plug or dome. Their rim to core texture reflects the competition between cooling and degassing timescales, which results in a dense crust with isolated vesicles contrasting with a highly vesicular vesicle network in the interior. Due to relatively fast quenching, the crust can shed light on pre‐ and syn‐eruptive conditions prior to or during fragmentation, whereas the interior allows us to explore post‐fragmentation vesiculation. Investigation of pre‐ to post‐fragmentation processes in breadcrust bombs from the 1999 Vulcanian activity at Guagua Pichincha, Ecuador, via 2D and 3D textural analysis reveals a complex vesiculation history, with multiple, spatially localized nucleation and growth events. Large vesicles (Type 1), present in low number density in the crust, are interpreted as pre‐eruptive bubbles formed by outgassing and collapse of a permeable bubble network during ascent or stalling in the plug. Haloes of small, syn‐fragmentation vesicles (Type 2), distributed about large vesicles, are formed by pressurization and enrichment of volatiles in these haloes. The nature of the pressurization process in the plug is discussed in light of seismicity and ground deformation signals, and previous textural and chemical studies. A third population (Type 3) of post‐fragmentation small vesicles appears in the interior of the bomb, and growth and coalescence of Type 2 and 3 vesicles causes the transition from isolated to interconnected bubble network in the interior. We model the evolution of viscosity, bubble growth rate, diffusion timescales, bubble radius and porosity during fragmentation and cooling. These models reveal that thermal quenching dominates in the crust whereas the interior undergoes a viscosity quench caused by degassing, and that the transition from crust to interior corresponds to the onset of percolation and development of permeability in the bubble network. Plain Language Summary: Breadcrust bombs are volcanic ejecta formed during explosive volcanic eruptions by rapid cooling of the exterior (the crust) and slow cooling of the interior that causes gas loss, bubble growth and cracking of the exterior. The rapidly cooled crust preserves characteristics of the magma prior to explosion. We study here the variations in porosity and vesicle properties from crust to interior in breadcrust bombs from the Guagua Pichincha volcano in Ecuador. Our results shed light on the pre‐eruptive conditions in the magma prior to explosive activity, and on the post‐fragmentation evolution of the bomb interior by bubble formation. Key Points: Vesicle textures in breadcrust bombs correlate with pre‐ to post‐fragmentation degassing processes during Vulcanian eruptionsLarge isolated vesicles preserved in the crust record a pre‐eruptive episode of outgassing and pressurization prior to fragmentationSmall vesicles provide insights into post‐fragmentation onset of permeability from the crust to the interior [ABSTRACT FROM AUTHOR]

In this paper, the excellent dimensional stability and vacuum outgassing of high-performance carbon fiber–reinforced plastic (CFRP) were discussed. First, the high-performance resin matrix was obtained by modifying cyanate resin, and the modified cyanate ester was used to make prepreg and laminates. Then, the mechanical property retention rate of laminates reached 90.79% under proton and electron irradiation. The average values of total mass loss and collected volatile condensable material of high-performance CFRP were 0.116% and 0.008%, respectively. Finally, the candidate tube and frame were fabricated based on the ply lay-up design. The candidate tube and frame were subjected to a series of experiments of thermal deformation and hygroscopic deformation to verify the dimensional stability. The thermal deformations of the tube and frame reached 0.468 μm/m and 4.579 μm/m, respectively, with a temperature variation of 4°C. The measured hygroscopic deformation of the tube reached 8.16 μm/m in nearly 3 months. The experimental results show that the high-performance CFRP can be used for precision optical structures of space telescopes. [ABSTRACT FROM AUTHOR]

• An experimental rig is developed to measure the oil pumping in refrigeration compressors. • The oil flow rate is investigated in the presence of atmospheric air and refrigerant fluid. • The effects of evaporating temperature, compressor speed and oil temperature are assessed. • The presence of refrigerant significantly reduces the oil flow rate compared to experiments conducted with atmospheric air. • Visualization of the outgassing process shows that sudden depressurization can lead to intermittent oil supply. The oil pumping plays a key role in the reliability and efficiency of compressors adopted in refrigeration systems. However, the investigations available in the literature on this subject do not consider the presence of the refrigerant and its effects on the oil supply. This paper reports the development of a novel experimental rig to measure the flow rate provided by the oil pump of a hermetic variable capacity reciprocating compressor considering the presence of the refrigerant in contact with the lubricating oil. A visualization system was also developed to investigate the transient outgassing phenomenon that takes place in the oil supply system when a sudden depressurization occurs, such as during the compressor startup. Measurements were carried out with the AB ISO VG 5 oil and the R-600a as the refrigerant fluid under different pairs of evaporating and condensing temperatures and compressor speed. Considering that the AB ISO VG 5 oil and air are immiscible, tests were also performed with air to isolate the effect of the refrigerant fluid on the oil supply. The results show that the oil flow rate is decreased due to the presence of refrigerant, with this effect becoming slightly stronger as the evaporating temperature is increased. The visualization system revealed that the outgassing brought about by the solubility between oil and refrigerant fluid has the potential to temporarily interrupt the oil supply. [ABSTRACT FROM AUTHOR]

Outgassing remains a pertinent issue in high-power systems as it can lead to effects such as breakdown, surface flashover, and pulse shortening and is typically the first stage of deleterious plasma formation. In this context, experimental reports suggest that carbon fibers (CFs) may likely be a superior cathode material for low outgassing. Here, model-based assessments of outgassing from CFs are performed based on molecular dynamics simulations. Carbon fibers were generated based on interconnection of an array of graphene sheets resembling ladder-like structures. Our results of temperature-dependent diffusion coefficients for hydrogen in CFs are shown to exhibit Arrhenius behavior and have values smaller than copper by factors of 15.5 and 86.8 at 400 K and 1000 K, respectively. This points to even stronger improvements for operation at high temperatures, with the asymptotic diffusion constant ratio predicted to be ∼187. With reduced outgassing, higher temperature operation, and durability, our results support CF cathodes as an excellent choice for cathode material in high-power microwave and pulsed power systems. [ABSTRACT FROM AUTHOR]

The volatiles released by the volcanic structures of the world contribute to natural environmental pollution both during the passive and active degassing stages. The Island of Vulcano is characterized by solfataric degassing mainly localized in the summit part (Fossa crater) and in the peripheral part in the Levante Bay. The normal solfataric degassing (high-temperature fumarolic area of the summit and boiling fluids emitted in the Levante Bay area), established after the last explosive eruption of 1888–90, is periodically interrupted by geochemical crises characterized by anomalous degassing that are attributable to increased volcanic inputs, which determine a sharp increase in the degassing rate. In this work, we have used the data acquired from the INGV (Istituto Nazionale di Geofisica e Vulcanologia) geochemical monitoring networks to identify, evaluate, and monitor the geochemical variations of the extensive parameters, such as the SO2 flux from the volcanic plume (solfataric cloud) and the CO2 flux from the soil in the summit area outside the fumaroles areas. The increase in the flux of volatiles started in June–July 2021 and reached its maximum in November of the same year. In particular, the mean monthly flux of SO2 plume of 22 tons day−1 (t d−1) and of CO2 from the soil of 1570 grams per square meter per day (g m2 d−1) increased during this event up to 89 t d−1 and 11,596 g m2 d−1, respectively, in November 2021. The average annual baseline value of SO2 output was estimated at 7700 t d−1 during normal solfataric activity. Instead, this outgassing increased to 18,000 and 24,000 t d−1 in 2021 and 2022, respectively, indicating that the system is still in an anomalous phase of outgassing and shows no signs of returning to the pre-crisis baseline values. In fact, in the first quarter of 2023, the SO2 output shows average values comparable to those emitted in 2022. Finally, the dispersion maps of SO2 on the island of Vulcano have been produced and have indicated that the areas close to the fumarolic source are characterized by concentrations of SO2 in the atmosphere higher than those permitted by European legislation (40 μg m−3 for 24 h of exposition) on human health. [ABSTRACT FROM AUTHOR]

Arctic warming alters land‐to‐sea fluxes of nutrients and organic matter, which impact air‐sea carbon exchange. Here we use an ocean‐biogeochemical model of the southeastern Beaufort Sea (SBS) to investigate the role of Mackenzie River biogeochemical discharge in modulating air‐sea CO2 fluxes during 2000–2019. The contribution of six biogeochemical discharge constituents leads to a net CO2 outgassing of 0.13 TgC yr−1, with a decrease in the coastal SBS carbon sink of 0.23 and 0.4 TgC yr−1 due to riverine dissolved organic and inorganic carbon, respectively. Years with high (low) discharge promote more CO2 outgassing (uptake) from the river plume. These results demonstrate that the Mackenzie River modulates the capacity of the SBS to act as a sink or source of atmospheric CO2. Our work suggests that accurate model representation of land‐to‐sea biogeochemical coupling can be critical for assessing present‐day Arctic coastal ocean response to the rapidly changing environment. Plain Language Summary: We modeled the discharge of freshwater and six biogeochemical constituents from the Mackenzie River into the southeastern Beaufort Sea to study their impact on ocean‐atmosphere carbon dioxide (CO2) fluxes during 2000–2019. We find that biogeochemical constituents from river runoff promote CO2 outgassing to the atmosphere in the river plume region. Dissolved inorganic carbon is the main contributor to this phenomenon, with river discharge events driving pulses of intense CO2 outgassing during ice‐free periods. Our results show that the capacity of the SBS to act as an atmospheric CO2 sink or source is strongly related to interannual variability in biogeochemical river discharge. Our results highlight the increased coupling of Arctic land‐ocean biogeochemical systems under rapid environmental changes. Key Points: Mackenzie River biogeochemical discharge decreases the southeastern Beaufort Sea carbon sinkTerrestrial dissolved inorganic carbon (DIC) is the primary driver of outgassing events in the SBS, followed by terrestrial DOCInterannual variability in river discharge modulates localized air‐sea CO2 flux [ABSTRACT FROM AUTHOR]

Silicate vapors play a key role in planetary evolution, especially dominating early stages of rocky planet formation through outgassed magma ocean atmospheres. Our open-source thermodynamic modeling software "VapoRock" combines the MELTS liquid model with gas-species properties from multiple thermochemistry tables. VapoRock calculates the partial pressures of 34 gaseous species in equilibrium with magmatic liquid in the system Si–Mg–Fe–Al–Ca–Na–K–Ti–Cr–O at desired temperatures and oxygen fugacities (f O2, or partial pressure of O2). Comparison with experiments shows that pressures and melt-oxide activities (which vary over many orders of magnitude) are reproduced to within a factor of ∼3, consistent with measurement uncertainties. We also benchmark the model against a wide selection of igneous rock compositions including bulk silicate Earth, predicting elemental vapor abundances that are comparable to (Na, Ca, and Al) or more realistic than (K, Si, Mg, Fe, and Ti) those of the closed-source MAGMA code (with maximum deviations by factors of 10–300 for K and Si). Vapor abundances depend critically on the activities of liquid components. The MELTS model underpinning VapoRock was calibrated and extensively tested on natural igneous liquids. In contrast, MAGMA's liquid model assumes ideal mixtures of a limited set of chemically simplified pseudospecies, which only roughly approximates the nonideal compositional interactions typical of many-component natural silicate melts. Finally, we explore how relative abundances of SiO and SiO2 provide a spectroscopically measurable proxy for oxygen fugacity in devolatilized exoplanetary atmospheres, potentially constraining f O2 in outgassed exoplanetary mantles. [ABSTRACT FROM AUTHOR]

Reduced (H 2 - and CH 4 -rich) and hyperalkaline fluids are products of subsurface reactions accompanying serpentinization of ultramafic rocks. H 2 and CH 4 produced during serpentinization can fuel microorganisms and support habitable subsurface environments. CH 4 is also a potent greenhouse gas and can offset negative greenhouse emissions arising from active CO 2 removal accompanying carbon mineralization in ultramafic rocks. However, the rate at which reduced volatiles are delivered to the surface and the rate of reactions that generate these volatiles at low-temperature conditions are poorly known. In this work, we measured H 2 and CH 4 outgassing rates in several hyperalkaline spring sites in the Samail ophiolite, Oman. H 2 and CH 4 outgassing in these sites are variable and range up to 70,000 and 7,000 mol yr−1, respectively. CH 4 outgassing in spring sites are unlikely to offset negative carbon emissions estimated from active carbon mineralization reactions in the Samail ophiolite. However, diffused CH 4 outgassing from peridotite outcrops remain unconstrained. Compositional and isotopic constraints show that volatiles are likely derived from active serpentinization, fluid inclusion decrepitation, or a combination of both. Calculated active serpentinization rates of up to 8 × 10−14 sec−1 account for measured outgassing rates and these are consistent with slow rates expected at low temperatures. In calculations of serpentinization rates, this work uses reaction-path models to account incorporation of both ferrous and ferric iron in the resulting alteration assemblages, which yields ∼0.3 mol H 2 kg−1 of ultramafic rock altered, lower than simulations based on iron oxidation to magnetite only. Contribution from decrepitation of H 2 - and CH 4 -bearing fluid inclusions is possible but would require much more mass of ultramafic rocks to account for observed outgassing. Further studies can help quantify extents of each source on active outgassing in Oman. Overall, this work shows that low-temperature serpentinization on geologically short timescales can account for observed flux of reduced volatiles in hyperalkaline environments. [ABSTRACT FROM AUTHOR]

In this contribution, we have investigated how polymeric matrix composites for aerospace applications are affected, when fabricated at low pressure, by the additive manufacturing process. Commercial filaments have been selected based on their representativeness of materials derived from lunar resources. Standard samples of thermoplastic polymers reinforced by organic fibers and inorganic fillers have been printed inside a vacuum chamber, and their mechanical and thermal properties have been characterized and discussed based on the printing conditions. The reported study represents a preliminary investigation of the potential applicability of the 3D printing technology on highly filled polymers for extraterrestrial applications. • Composite materials are fabricated by FDM inside a vacuum chamber. • Filler materials are representative of resources derived from the lunar environment. • Thermal and mechanical properties are preserved upon low-pressure printing. • A modest dimensional deviation is reported after analysis of standard samples. [ABSTRACT FROM AUTHOR]

The Meridian Project's sounding rocket mission uses a mass spectrometer to conduct in-situ atmospheric detection. In order to assess the influence of surface material outgassing and the attitude control jet on the spectrometer's detection, a sounding rocket platform was modeled and simulated. Using the physical field simulation software COMSOL and the Monte Carlo method, this study investigated whether the gas molecules from the two cases could enter the in-situ atmospheric mass spectrometer's sensor sampling port after colliding with the background atmosphere. The simulation results show that the influence of surface material outgassing on the in-situ atmospheric detection is very small, even under the conditions of medium solar activity and medium geomagnetic activity, while the influence of the attitude control jet on the in-situ atmospheric detection is large but can be reduced by reducing the low-altitude attitude control operation and decreasing the transmission probability. Through simulation optimization and according to engineering needs, increasing the nozzle outlet cross-sectional area, increasing the temperature of the gas used for attitude control, increasing the nozzle rotation angle, increasing the nozzle outlet angle, or increasing the nozzle center height can reduce the transmission probability. This model can simulate and analyze the influence of both surface material outgassing and attitude control jets on in-situ atmospheric detection, optimize relevant parameters, and provide new ideas for relevant work. [ABSTRACT FROM AUTHOR]

Aims. Understanding the activity is vital for deciphering the structure, formation, and evolution of comets. We investigate models of cometary activity by comparing them to the dynamics of 67P/Churyumov-Gerasimenko. Methods. We matched simple thermal models of water activity to the combined Rosetta datasets by fitting to the total outgassing rate and four components of the outgassing induced non-gravitational force and torque, with a final manual adjustment of the model parameters to additionally match the other two torque components. We parametrised the thermal model in terms of a distribution of relative activity over the surface of the comet, and attempted to link this to different terrain types. We also tested a more advanced thermal model based on a pebble structure. Results. We confirm a hemispherical dichotomy and non-linear water outgassing response to insolation. The southern hemisphere of the comet and consolidated terrain show enhanced activity relative to the northern hemisphere and dust-covered, unconsolidated terrain types, especially at perihelion. We further find that the non-gravitational torque is especially sensitive to the activity distribution, and to fit the pole-axis orientation in particular, activity must be concentrated (in excess of the already high activity in the southern hemisphere and consolidated terrain) around the south pole and on the body and neck of the comet over its head. This is the case for both the simple thermal model and the pebble-based model. Overall, our results show that water activity cannot be matched by a simple model of sublimating surface ice driven by the insolation alone, regardless of the surface distribution, and that both local spatial and temporal variations are needed to fit the data. Conclusions. Fully reconciling the Rosetta outgassing, torque, and acceleration data requires a thermal model that includes both diurnal and seasonal effects and also structure with depth (dust layers or ice within pebbles). This shows that cometary activity is complex. Nonetheless, non-gravitational dynamics provides a useful tool for distinguishing between different thermophysical models and aids our understanding. [ABSTRACT FROM AUTHOR]

In 1999–2001, Guagua Pichincha volcano, Ecuador, produced a series of cyclic explosive and effusive eruptions. Rock samples, including dense blocks and pumiceous clasts collected during the eruption sequence, and ballistic bombs later collected from the crater floor, provide information about magma storage, ascent, decompression, degassing, repressurization, and regassing prior to eruption. Pairs of Fe-Ti oxides indicate equilibrium within 1.2–1.5 log units above the NNO oxidation buffer and equilibrium temperatures from 805 to 905 °C. Melt inclusions record H2O contents of 2.7–4.6 wt% and CO2 contents (uncorrected for CO2 segregation into bubbles) from 19 to 310 ppm. Minimum melt inclusion saturation pressures fall between 69 and 168 MPa, or equilibration depths of 2.8 and 6.8 km, the lower end of which is coincident with the maximum inferred equilibration depths for the most vesicular breadcrust bombs sampled. Amphibole phenocrysts lack breakdown rims (except for one sample) and plagioclase phenocrysts have abundant oscillatory compositional zones. Plagioclase areal microlite number densities (Na) range over less than one order of magnitude (8.9×103–8.7×104 mm-2) among all samples, with the exception of a dense, low crystallinity sample (Na = 3.0×103 mm−2) and a pumiceous sample erupted on 17 December 1999 (Na = 1.7×103 mm−2). Plagioclase microlite shapes include tabular, hopper, and swallowtail forms. Taken together, the relatively high plagioclase microlite number densities, the high number of oscillatory zones in plagioclase phenocrysts, the presence of CO2 in groundmass glass, seismicity, and time-varying tilt cycles provide a picture of sudden evacuation of magma residing at different levels in the shallow conduit. Explosive eruptions punctuate inter-eruptive repose periods marked by time-varying rates of degassing (volatile fluxing) and re-pressurization. Shallow residence time in the conduit was sufficient to allow precipitation of silica-phase in the groundmass, but insufficient to allow breakdown of hornblende phenocrysts, with the one exception of the final dome sample from 2000, which has the longest preceding repose time. These results support a model of cyclic pressure cycling, volatile exsolution and regassing, and magma decompression decoupled from ascent. [ABSTRACT FROM AUTHOR]

The large amounts of organic carbon buried in mangrove wetlands are well recognized, but the lateral dissolved carbon export and greenhouse gas (GHGs) outgassing are often overlooked. In this study, we carried out seasonal observations of dissolved carbon and GHGs in an estuarine mangrove wetland with high input of riverine nitrogen in southeast China in 2019–2020. The results showed that the tidal range and season were the two main factors controlling the lateral dissolved carbon export including total alkalinity (TA), dissolved inorganic carbon (DIC) and dissolved organic carbon (DOC). The positive correlations between the average offsets of DIC, TA, DOC and tidal range confirmed the hydrological controls on the exchange of dissolved carbon between the mangrove creek and the estuary. The seasonal variability in temperature, groundwater export and freshwater input resulted in a larger carbon offset during low tidal range in spring and a smaller offset during high tidal range in fall. The mangrove creek acted as a net source of DIC, DOC, TA and GHGs. When the emissions of GHGs were calculated as CO2-equivalents, the average emission of CO2 was four times higher than that of N2O and the average emission of N2O was six times higher than that of CH4. In contrast with pristine mangroves, denitrification in mangrove wetlands with high input of riverine nitrogen played a crucial role in mineralization processes, leading to the production of DIC, TA and N2O. These biogeochemical processes may not be conducive to the blue carbon sequestration in mangrove soils. These findings suggested that there are mutual benefits between the reduced loss of blue carbon and the mitigation of eutrophication when restoring mangrove wetlands and reducing nitrogen pollution. [ABSTRACT FROM AUTHOR]

On 4 August 2020, a strong explosion occurred near the Beirut seaport, Lebanon and killed more than 200 people and damaged numerous buildings in the vicinity. As Amonium Nitrate (AN) caused the explosion, many studies claimed the release of large amounts of NO2 in the atmosphere may have resulted in a health hazard in Beirut and the vicinity. In order to reasonably evaluate the significance of NO2 amounts released in the atmosphere, it is important to investigate the spatio-temporal distribution of NO2 during and after the blast and compare it to the average day-to-day background emissions from vehicle and ship traffic in Beirut. In the present study, we use Sentinel-5 TROPOMI data to study NO2 emissions in the atmosphere close to the affected area prior, during, and after the Beirut explosion (28 July–8 August 2020). Analysis shows an increase in NO2 concentrations over Beirut up to about 1.8 mol/m2 one day after the explosion that was gradually dissipated in about 4 days. Seven days before the blast (on 28 July 2020) NO2 concentration was, however, observed to be up to about 4.3 mol/m2 over Beirut, which is mostly attributed to vehicle emissions in Lebanon, ships passing by the Beirut seaport and possibly the militant activities in Syria during 20–26 July. It is found that the Beirut blast caused a temporarily and spatially limited increase in NO2. The blast mostly affected the coastal areas in Lebanon, while it did not have much effect on inland regions. TROPOMI data are also analyzed for the Greater Cairo Area (GCA), Suez Canal, Egypt, and in Nicosia, Cyprus to confirm the effect of human activities, vehicles, and ship traffic on NO2 emissions in relatively high and relatively low populated zones. [ABSTRACT FROM AUTHOR]

This work presents two different encapsulation strategies for perovskite photodetectors by testing the device stability under elevated ambient humidity of 85% and room temperature (25 °C). The single layer structure is adopted in the devices in order to accelerate the aging tests. The best stability (retention of ≈90% of initial photoresponsivity on average after 24 h, and ≈73% after 168 h) is obtained for devices protected by a flexible UV‐curable resin shell and encapsulated with AB epoxy including a desiccant sheet. The effects of the epoxy outgassing, the presence of desiccant, and the bending ability of encapsulated devices are also investigated. Additionally, with the assistance of 3D printing technology, a new possibility of research in the aspect of electrical device encapsulation is developed. Rapid iterative modifications in materials, shape, inner structure, and easy integration with outer component like desiccant ball/sheet make 3D printing assistance an ideal solution for the design of the encapsulation configuration and its early verification. This work not only opens up an optimal way for perovskite encapsulation by the 3D printing technology, but also provides an ideal solution for the design of the encapsulation configuration and its early verification. [ABSTRACT FROM AUTHOR]

The environment of a comet is a fascinating and unique laboratory to study plasma processes and the formation of structures such as shocks and discontinuities from electron scales to ion scales and above. The European Space Agency's Rosetta mission collected data for more than two years, from the rendezvous with comet 67P/Churyumov-Gerasimenko in August 2014 until the final touch-down of the spacecraft end of September 2016. This escort phase spanned a large arc of the comet's orbit around the Sun, including its perihelion and corresponding to heliocentric distances between 3.8 AU and 1.24 AU. The length of the active mission together with this span in heliocentric and cometocentric distances make the Rosetta data set unique and much richer than sets obtained with previous cometary probes. Here, we review the results from the Rosetta mission that pertain to the plasma environment. We detail all known sources and losses of the plasma and typical processes within it. The findings from in-situ plasma measurements are complemented by remote observations of emissions from the plasma. Overviews of the methods and instruments used in the study are given as well as a short review of the Rosetta mission. The long duration of the Rosetta mission provides the opportunity to better understand how the importance of these processes changes depending on parameters like the outgassing rate and the solar wind conditions. We discuss how the shape and existence of large scale structures depend on these parameters and how the plasma within different regions of the plasma environment can be characterised. We end with a non-exhaustive list of still open questions, as well as suggestions on how to answer them in the future. [ABSTRACT FROM AUTHOR]

The chemical composition of gases emitted by active volcanoes reflects both magma degassing and shallower processes, such as fluid-rock hydrothermal interaction and mixing with atmospheric-derived fluids. Untangling the magmatic fluid endmember within surface gas emission is therefore challenging, even with the use of well-known magma degassing tracers such as noble gases. Here, we investigate the deep magmatic fluid composition at the Nisyros caldera (Aegean Arc, Greece) by measuring nitrogen and noble gas abundances and isotopes in naturally degassing fumaroles. Gas samples were collected from 32 fumarolic vents at water-boiling temperature between 2018 and 2021. These fumaroles are admixtures of magmatic fluids typical of subduction zones, groundwater (or air saturated water, ASW), and air. The N 2 , He, and Ar composition of the magmatic endmember is calculated by reverse mixing modeling and shows N 2 /He = 31.8 ± 4.5, N 2 /Ar = 281.6, δ 15N = +7 ± 3 ‰, 3He/4He = 6.2 Ra (where Ra is air 3He/4He), and 40Ar/36Ar = 551.6 ± 19.8. Although N 2 /He is significantly low with respect to typical values for arc volcanoes (1,000–10,000), the contribution of subducted sediments to the Aegean Arc magma generation is reflected by the positive δ 15N values of Nisyros fumaroles. The low N 2 /He ratio indicates N 2 -depletion due to solubility-controlled differential degassing of an upper-crustal silicic (dacitic/rhyodacitic) melt in a high-crystallinity reservoir. We compare our 2018–2021 data with N 2 , He, and Ar values collected from the same fumaroles during a hydrothermal unrest following the seismic crisis in 1996–1997. Results show additions of both magmatic fluid and ASW during this unrest. In the same period, fumarolic vents display an increase in magmatic species relative to hydrothermal gas, such as CO 2 /CH 4 and He/CH 4 ratios, an increase of ∼50 °C in the equilibrium temperature of the hydrothermal system (up to 325 °C), and greater amounts of vapor separation. These variations reflect an episode of magmatic fluid expulsion during the seismic crisis. The excess of heat and mass supplied by the magmatic fluid injection is then dissipated through boiling of deeper and peripheral parts of the hydrothermal system. Reverse mixing modeling of fumarolic N 2 -He-Ar has therefore important ramifications not only to disentangle the magmatic signature from gases emitted during periods of dormancy, but also to trace episodes of magmatic outgassing and better understand the state of the upper crustal reservoir. [ABSTRACT FROM AUTHOR]

Arctic shelf seas receive greater quantities of river runoff than any other ocean region and are experiencing increased freshwater loads and associated terrestrial matter inputs since recent decades. Amplified terrestrial permafrost thaw and coastal erosion is exposing previously frozen organic matter, enhancing its mobilization and release to nearshore regions. Changing terrestrial dissolved organic matter (terr-DOM) loads and composition may alter shelf primary productivity and respiration, ultimately affecting net regional CO2 air–sea fluxes. However, the future evolution of Arctic Ocean climate feedbacks are highly dependent upon the biological degradability of terr-DOM in coastal waters, a factor often omitted in modelling studies. Here, we assess the sensitivity of CO2 air–sea fluxes from East Siberian Arctic Shelf (ESAS) waters to changing terr-DOM supply and degradability using a biogeochemical model explicitly accounting for bacteria dynamics and shifting terr-DOM composition. We find increasing terr-DOM loads and degradability trigger a series of biogeochemical and ecological processes shifting ESAS waters from a net sink to a net source of CO2, even after accounting for strengthening coastal productivity by additional land-derived nutrients. Our results suggest that future projected inputs of labile terr-DOM from peat and permafrost thaw may strongly increase the CO2 efflux from the Arctic shelf sea, causing currently unquantified positive feedback to climate change. [ABSTRACT FROM AUTHOR]

The pumping speed measuring apparatus, which employs the flowmeter method, was introduced. The pressure was measured by using a spinning rotor gauge(SRG) under 1×10-4 to 1×10-2Pa, and the ionization vacuum gauge was used when the pressure was lower than 10-4Pa. A method of measuring the pumping speed and the outgassing rate of the extractor gauge was given. The pumping speed and the outgassing rate of the extractor gauge were measured under the pressure of 10-6 to 10-4Pa. The flowmeter method was used to measure the pumping speed of the miniature sputter ion pump(SIP)in nitrogen and helium. The discharge state of the miniature SIP under different pressures was analyzed using COMSOL, and the experimental results were in good agreement with the theoretical analysis. The combined standard uncertainty of the flowmeter method was less than 4.4%. [ABSTRACT FROM AUTHOR]

• Textural analysis was performed on basanitic deep submarine lavas from the 2018–2021 Fani Maoré eruption. • Pillow selvages are either highly vesiculated (max 50%) or very massive (<1%). • Heterogeneous textures result from ascent and effusion rate variations with time. • Fani Maoré lavas experienced different degrees of degassing and outgassing. • This submarine lava flow fields was dominantly tube-fed due to high effusion rates (11–200 m3/s). The 2018–2021 Fani Maoré submarine eruption (offshore of Mayotte, Mozambique Channel) extruded a bulk volume of ∼6.5 km3 of basanite magma onto the seafloor at a depth of 3300 m, with effusion rates ranging from 150 to 200 m3/s in the first year of the eruption, to less than 11 m3/s in the final months. Six oceanographic campaigns provided a large sample set covering the entire flow field at high spatial and temporal resolution. These samples allow us to precisely track syn-eruptive degassing processes through quantification of textural parameters including porosity, pore connectivity, vesicle number density (N V) and vesicle size distributions (VSD). Three different textural facies have been distinguished. (1) Vesicular lavas (average porosity of 35%) display unimodal VSDs, high N V (14–214 mm−3), and small and spherical vesicles. (2) Lavas with intermediate porosities (25%) have scarce small vesicles, VSDs shifted towards larger vesicles, and low N V (0.2–39 mm−3). (3) Dense lavas with low porosities (14%) display bimodal VSDs distribution, a dominant mode of small vesicles, and low N V (0–87 mm−3). The early phase of activity (Phase 1, June 2018 – May 2019) built the main edifice and was fed by rapid ascent and closed-system degassing of volatile-rich magma ascending from a deep reservoir to the seafloor (Facies 1). Distal samples collected from lava flows emitted during Phase 2, between June and July 2019, show large and irregular shape vesicles mostly related to bubble growth and coalescence, and outgassing during emplacement (Facies 2). These lavas are interpreted to be emplaced during extension of a lava tube system which began to develop during Phase 1. The final phase (Phase 3, August 2019 – January 2021) was associated with lava effusion located at the northwest lava flow front, 6 km from the summit. Phase 3 involved a more degassed magma due to the increase in the length of the magma pathway (Facies 3). Phase 3 lavas were also extremely outgassed and associated with construction of a new complex lava flow field with tumuli and multiple ephemeral vents (lava breakouts). The heterogeneous textures within the studied samples reflect changing ascent and effusion rates with time, leading to emplacement of lava flows which varied depending on the degree of degassing and effusion rate. We conclude that emplacement of the Fani Maoré large submarine lava flow fields developed through extensive and prolonged tube systems this being supported by the high effusion rates. [ABSTRACT FROM AUTHOR]

The article evaluates the EP17HTDA-2, a one-component epoxy offered by Master Bond.

Water inventories in Martian magmas are poorly constrained. Meteorite‐based estimates range widely, from 102 to >104 ppm H2O, and are likely variably influenced by degassing. Orbital measurements of H primarily reflect water cycled and stored in the regolith. Like water, Th behaves incompatibly during mantle melting, but unlike water Th is not prone to degassing and is relatively immobile during aqueous alteration at low temperature. We employ Th as a proxy for original, mantle‐derived H2O in Martian magmas. We use regional maps of Th from Mars Odyssey to assess variations in magmatic water across major volcanic provinces and through time. We infer that Hesperian and Amazonian magmas had ∼100–3,000 ppm H2O, in the lower range of previous estimates. The implied cumulative outgassing since the Hesperian, equivalent to a global H2O layer ∼1–40 m deep, agrees with Mars' present‐day surface and near‐surface water inventory and estimates of sequestration and loss rates. Plain Language Summary: Past volcanism on Mars has supplied some of the water that carved ancient river valleys and shaped the chemistry of the Martian near‐surface. However, the amount of water carried by Martian magmas is an open question, in part because igneous rocks and meteorites have often lost their original water contents through degassing. The trace element thorium can be used as a proxy for magmatic water, because thorium and water are transferred in similar proportions to magmas during mantle melting, but thorium does not degas. We use regional maps of thorium from the Mars Odyssey spacecraft to track variations in magmatic water through time and across major volcanic provinces. Key Points: Thorium partitions similarly to H2O during Martian mantle melting but does not degas, and is useful as a proxy for primary magmatic H2OGamma Ray Spectroscopy maps of thorium distribution are used to track variations in primary magmatic H2O through Mars' historyWe infer that Hesperian and Amazonian magmas had ∼100–3,000 ppm H2O, implying outgassing of a global H2O layer ∼1–40 m deep [ABSTRACT FROM AUTHOR]

The results of a study of outgassing of boron carbide and durable ultrahigh molecular weight polymethyl methacrylate (organic glass) in vacuum are presented. It is shown that boron carbide manufactured by OOO Virial (St. Petersburg) by the cold-pressing technique, which is followed by free sintering at a temperature of approximately 2200°C, meets the requirements that are stated by the ITER (International Thermonuclear Experimental Reactor). The results studying ultrahigh molecular weight durable polymethyl methacrylate (UMW-PMMA), which was manufactured at the Institute of Solid-State Chemistry and Mechanochemistry, Siberian Branch, Russian Academy of Sciences (ISSCM SB RAS) using original technologies, showed that UMW-PMMA with frontal polymerization has the lowest gas emission compared to "conventional" PMMA and is very promising for the manufacture of specialized vacuum chambers for electrophysical facilities. [ABSTRACT FROM AUTHOR]

Outgassing of carbon dioxide from the Earth's interior regulates the surface climate through deep time. Here we examine the role of cratonic destruction in mantle CO2 outgassing via collating and presenting new data for Paleozoic kimberlites, Mesozoic basaltic rocks and their mantle xenoliths from the eastern North China Craton (NCC), which underwent extensive destruction in the early Cretaceous. High Ca/Al and low Ti/Eu and δ 26Mg are widely observed in lamprophyres and mantle xenoliths, which demonstrates that the cratonic lithospheric mantle (CLM) was pervasively metasomatized by recycled carbonates. Raman analysis of bubble-bearing melt inclusions shows that redox melting of the C-rich CLM produced carbonated silicate melts with high CO2 content. The enormous quantities of CO2 in these magmas, together with substantial CO2 degassing from the carbonated melt–CLM reaction and crustal heating, indicate that destruction of the eastern NCC resulted in rapid and extensive mantle CO2 emission, which partly contributed to the early Cretaceous greenhouse climate episode. [ABSTRACT FROM AUTHOR]

Identifying the causes and consequences of natural variations in ocean acidification and atmospheric CO2 due to complex earth processes has been a major challenge for climate scientists in the past few decades. Recent developments in the boron isotope (δ11B) based seawater pH and pCO2 (or pCO2sw) proxy have been pivotal in understanding the various oceanic processes involved in air-sea CO2 exchange. Here we present the first foraminifera-based δ11B record from the north-eastern Arabian Sea (NEAS) covering the mid-late Holocene (~ 8–1 ka). Our record suggests that the region was overall a moderate to strong CO2 sink during the last 7.7 kyr. The region behaved as a significant CO2 source during two short intervals around 5.5–4 ka and 2.8–2.5 ka. The decreased pH and increased CO2 outgassing during those abrupt episodes are associated with the increased upwelling in the area. The upwelled waters may have increased the nutrient content of the surface water through either increased supply or weaker export production. This new dataset from the coastal NEAS suggests that, as a potential result of changes in the strength of the El-Nino Southern Oscillation, the region experienced short episodes of high CO2 outgassing and pre-industrial ocean acidification comparable to or even greater than that experienced during the last ~ 200 years. [ABSTRACT FROM AUTHOR]

Coriolis Vibratory Gyroscope (CVG) is an inertial angular rate measurement sensor. CVG sensor comprises of metal coated hemispherical quartz vibrating structure as the rotation sensing element. It is forced to vibrate at one of its resonant modes by electrostatic excitation. Because of the limited flexibility of the quartz sensing element, the amplitude is limited to the submicron level. An ultra-high vacuum environment is required for the sensing element to sustain vibration for a long time. The criticality in the sensor development is to maintaining an ultra-high vacuum environment for the sensing element. Sensor suffers a problem of vacuum instability during the operation due to the outgassing from its components. This paper presents a novel approach in the identification of various outgassing sources that exist in the sensor, mitigation plan to minimize outgassing rate by selection of suitable raw material, suitable fabrication process of the components, and the surface characterization etc. The research work also presents the cost-effective experimental methodology to measure the outgassing rate from the sensor components to assess the CVG vacuum life, the requirement of the getter to maintain the ultra-high vacuum level throughout the CVG operation. [ABSTRACT FROM AUTHOR]

Photopolymer resins are applied at an increasing rate in additive manufacturing (AM) industry as vat photopolymerization (VP) and material jetting (MJ) methods gain more popularity. The aim of this study was to measure volatile organic compound (VOC), carbonyl compound, ultrafine particle (UFP), and particulate matter (PM10) air concentrations emitted in 3D printer operations. Individual chemicals were identified when multiple photopolymer resin feedstocks were used in various VP and MJ printers. The size distributions of UFPs, and indoor air parameters were also monitored. Finally, the VOC outgassing of the cured resin materials was determined over 84 days. The data demonstrated that 3D printer operators were exposed to low concentrations of airborne exposure agents as follows: average concentrations of VOCs were between 41 and 87 µg/m3, UFP number levels ranged between 0.19 and 3.62 × 103 number/cm3; however, no impact was detected on air parameters or PM10 concentrations. A majority of the UFPs existed in the 10–45 nm size range. The identified compounds included hazardous species included sensitizing acrylates and carcinogenic formaldehyde. The outgassed products included similar compounds that were encountered during the AM processes, and post-processing solvents. Products heated to 37°C emitted 1.4‒2.9-fold more VOCs than at room temperature. Total emissions were reduced by 84‒96% after 28 days roughly from 3000–14000 to 100–1000 µg/m2/hr. In conclusion, resin printer operators are exposed to low concentrations of hazardous emissions, which might result in adverse health outcomes during prolonged exposure. Manufactured resin products are suggested to be stored for 4 weeks after their production to reduce potential consumer VOC hazards. [ABSTRACT FROM AUTHOR]

The Solar Radiation and Climate Experiment (SORCE) and Total and Spectral Irradiance Sensor (TSIS‐1) conducted an intercomparison for the two Spectral Irradiance Monitors (SIM) spanning 704 days from 23 March 2018 to 25 February 2020 and permitted 554 time‐matched pairs of observations. This comparison was conducted during the extremely quiescent Solar Cycle 24 minimum, so all observed differences and drifts between the two sensors are instrumental in nature. The TSIS‐1 SIM benefitted from advanced calibration capabilities based on SI standards that were not available during the preflight calibration time period of SORCE. For this reason, a revision of the SORCE SIM absolute scale is appropriate. As expected, wavelength dependent differences in absolute agreement are a function of detector sensitivity and local changes in spectral slope. At the time of the comparison SORCE SIM has been on‐orbit for 17 years while TSIS‐1 observations commenced immediately after a 100‐day outgassing and commissioning period. Peak‐to‐peak absolute scale differences are about 12% with a mean fractional difference of 0.7% ± 2.9%. The greatest scale differences occur at the change‐over between the UV and visible photodiodes in the 310 nm region, and a systematic disagreement is present in the 850–1,600 nm range. A multiplicative scale correction factor has been developed to reconcile the TSIS‐1 and SORCE difference with a wavelength dependent error on the mean typically less than 0.01% derived from every matched pair of observations. Key Points: Conduct a comparison of Solar Radiation and Climate Experiment (SORCE) and Total and Spectral Irradiance Sensor (TSIS‐1) Spectral Irradiance Monitors (SIM) over a 705‐day time periodConstruct a multiplicative correction factor that brings the SORCE SIM into agreement with the pre‐flight calibration of TSIS‐1 SIMCharacterize the uncertainties associated with the correction factor—uncertainty was two orders of magnitude less than the correction [ABSTRACT FROM AUTHOR]

Hydrogen embrittlement (HE) is among the limiting factors for the employment of advanced high-strength steels in the automotive industry. One of the most relevant manifestations of HE for those components is delayed fracture. To perform HE risk assessment against delayed fracture in structural components wherein hydrogen accumulates near notches or bends after manufacturing or assembly, continuum models can be used to predict hydrogen diffusion and accumulation. To this aim, it is crucial to identify both the correct model parameters and boundary conditions (BCs). This study provides the required modelling and experimental framework to estimate the constitutive diffusion, trapping and outgassing parameters for a commercial martensitic advanced high-strength steel grade 1300. Permeation testing and simple room outgassing tests showed that a natural BC with one-parameter effectively reproduces the experimental results. The proposed model can be used to predict a reasonable hydrogen distribution, both inside of the component and near to the surface, which is valuable for HE risk assessments. Finally, the same BC can be employed with the interpretation of ex-situ hydrogen charged tensile tests. • Multiple permeation tests allow for identification of hydrogen trapping parameters. • Zero-flux and zero-concentration boundary conditions are unsatisfactory. • Natural boundary conditions can reproduce room temperature outgassing tests. • A prediction of surface hydrogen on metal–air boundary is obtained. [ABSTRACT FROM AUTHOR]

In this work, the outgassing and deposition features of helium (He) in Al–He co-deposition layers have been studied using a long-pulse (τ ≈ 750 μs) laser combined with quadrupole mass spectroscopy (QMS) diagnostic approach. The He/Al co-deposited layers were prepared by pulse laser deposition. The spatially laterally-resolved measurements indicated that the co-deposited He is relatively homogeneous and can satisfy the need for laser parametric scanning. Laser-induced He outgassing behavior was studied under a series of heat flux factors (HFFs) spanning laser heating, melting and ablation and are used as a parameter to evaluate the transient heat load on the co-deposition layer. The outgassing behavior of He in co-deposited layer is strongly dependent on the temperature distribution. It was found that the slopes of the long pulse laser-induced He-outgassing curves in the melting and ablation stages are significantly less than that in the heating stage. Notably, the laser-induced He-outgassing features is also influenced by the He retention mechanism, which has been elaborated by comparing the experimental results with the thermal desorption spectroscopy (TDS). Laser induced complete melting or even ablation could completely release the He in the co-deposited layer and, noticeably, shows a weak correlation with its retention behavior, which is important for the accurate quantitative analysis and removal of D/He deposited under complicated conditions. • Long pulse laser combined with quadrupole mass spectroscopy was employed to investigate He retention in co-deposited layer. • Laser-induced He outgassing behavior was studied under a series of heat flux factors (HFFs) which span three stages of laser heating, melting and ablation. • The slopes of the long pulse laser-induced He-outgassing curves in the melting and ablation stages are significantly less than that in the heating stage. • The laser-induced He-outgassing features is also influenced by the He retention mechanism. • Laser induced complete melting or even ablation could completely release the He in the co-deposited layer and show a weak correlation with its retention behavior. [ABSTRACT FROM AUTHOR]

A silica-filled polydimethylsiloxane (PDMS) composite M9787 was investigated for potential outgassing in a vacuum/dry environment with the temperature programmed desorption/reaction method. The outgassing kinetics of 463 K vacuum heat-treated samples, vacuum heat-treated samples which were subsequently re-exposed to moisture, and untreated samples were extracted using the isoconversional and constrained iterative regression methods in a complementary fashion. Density functional theory (DFT) calculations of water interactions with a silica surface were also performed to provide insight into the structural motifs leading to the obtained kinetic parameters. Kinetic analysis/model revealed that no outgassing occurs from the vacuum heat-treated samples in subsequent vacuum/dry environment applications at room temperature (~300 K). The main effect of re-exposure of the vacuum heat-treated samples to a glove box condition (~30 ppm by volume of H2O) for even a couple of days was the formation, on the silica surface fillers, of ~60 ppm by weight of physisorbed and loosely bonded moisture, which subsequently outgasses at room temperature in a vacuum/dry environment in a time span of 10 yr. However, without any vacuum heat treatment and even after 1 h of vacuum pump down, about 300 ppm by weight of H2O would be released from the PDMS in the next few hours. Thereafter the outgassing rate slows down substantially. The presented methodology of using the isoconversional kinetic analysis results and some appropriate nature of the reaction as the constraints for more accurate iterative regression analysis/deconvolution of complex kinetic spectra, and of checking the so-obtained results with first principle calculations such as DFT can serve as a template for treating other complex physical/chemical processes as well. [ABSTRACT FROM AUTHOR]