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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 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 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]

• 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]

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 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]

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]

• 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]

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]

The Krafla geothermal system is located within a volcanic center that periodically erupts basaltic lavas, and has recently attracted an economic interest due to supercritical fluids forming near a shallow magma intrusion (∼ 2 km depth). Here, we discuss new soil CO 2 flux and stable isotope data of the CO 2 efflux (δ13C) and hydrothermal calcites (δ13C, δ18O) of drill cuttings to estimate both the current magmatic outgassing from soils and the thermal flows in the geothermal system. Soil CO 2 emission is controlled by tectonics, following the NNE-SSW fissure swarm direction and a WSW-ENE trend, and accounts for ∼62.5 t d−1. While the δ18O of the H 2 O in equilibrium with deep calcites is predominantly meteoric, both the δ13C of the soil CO 2 efflux and of the fluids from which calcite precipitated have a clear magmatic origin, overlapping the δ13C estimated for the Icelandic mantle (−2.5 ± 1.1 ‰). Estimates based on the soil CO 2 emission from the southern part of the system show that these fluxes might be sustained by the ascent and depressurization of supercritical fluids with a thermal energy of ∼800 MW. Such significant amount of energy might reach 1.5 GW if supercritical conditions extended below the whole investigated area. Finally, we report an increase in the soil CO 2 emission of about 3 times with respect to 14 years ago, likely due to recent changes in the fluid extracted for power production or magmatic activity. Pairing the soil CO 2 emission with stable isotopes of the efflux and calcite samples has important implications for both volcano monitoring and geothermal exploration, as it can help us to track magmatic fluid upflows and the associated thermal energy. • Krafla geothermal field naturally emits 62.5 t d−1 of CO 2 from soils into the atmosphere. • δ13C of both CO 2 and hydrothermal calcites reveals a magmatic origin. • Supercritical fluids with a significant thermal energy (up to 1.5 GW) might feed the CO 2 emission. • The soil CO 2 emission has increased about 3 times in the last 14 years. • Such increase is ascribed to changes in geothermal production or magmatic activity. [ABSTRACT FROM AUTHOR]

• We report the first mantle degassing transect across a continental convergent margin. • Three levels of mantle He degassing are recognized based on 3He/4He distribution. • Causes for possible decoupled He-Sr isotopes of Quaternary basalts are explored. • Volatile origin and outgassing are controlled by continental convergence processes. Mantle degassing transect across different tectonic units within a plate convergent setting has been well documented for oceanic convergent margins by systematic changes in geochemistry (e.g., 3He/4He, δ13C, and CO 2 /3He) of hydrothermal gases. However, little is known about spatial variations in volatile geochemistry across a continental convergent margin. In this study, we identify a mantle degassing transect in the southeastern Tibetan Plateau using He-CO 2 systematics of hydrothermal gases, which extends from India-Asia continental convergent margin to intra-continent extensional region. δ13C-CO 2 (−11.8‰ to −3.1‰) and CO 2 /3He (1.7 × 108 to 7.1 × 1011) values of hydrothermal gases show large variations that are consistent with modification by secondary physico-chemical processes, such as multi-component mixing, hydrothermal degassing, and calcite precipitation. Three levels of He degassing can be recognized based on 3He/4He dataset (0.01–5.87 R A) of the hydrothermal gas samples and their distances to volcanic centers. A magmatic level He degassing (35–74% mantle He) is found near active and/or Quaternary volcanoes fed by mantle-derived magmas. With increasing distance to volcanic centers, the outgassed magmatic volatiles are gradually diluted by crustal components (e.g., radiogenic 4He), defining a transitional level He degassing (13–33% mantle He). The 3He/4He values (8.16–8.48 R A) of olivine phenocrysts indicate a MORB (mid-ocean ridge basalts)-type mantle source for the magmatic and transitional levels of He degassing that are localized in Quaternary volcanic fields. In contrast, a background level He degassing (<12% mantle He) dominates the entire study area, and can be attributed to (i) degassing of sub-continental lithospheric mantle, and/or (ii) higher degrees of crustal contamination than those of the transitional level He degassing near volcanic centers. Combined with olivine 3He/4He data reported in this study and whole-rock 87Sr/86Sr data of host basalts from literature, source components of the mantle-derived magmas are suggested to include the MORB-type convective mantle, subducted Indian slab materials, and less degassed mantle materials, which can account for the possible decoupling between He and Sr isotope systematics. These findings delineate the origin and outgassing of mantle volatiles controlled by the India-Asia continental convergence, and would contribute to a better understanding of the deeply-sourced volatile emissions in these tectonic settings. [ABSTRACT FROM AUTHOR]

• Massive CO 2 mobilisation from ophicarbonate around shallow intrusions. • Mixed H 2 O-CO 2 fluids dominate metamorphic carbon degassing at collisional plate boundaries. • Metamorphic ultramafic rocks with >50% tremolite or diopside likely were ophicarbonate. • Metamorphic CO 2 degassing may be highly relevant for the long-term global carbon cycle. The processes of carbon mobilisation at convergent plate boundaries are hotly debated. Recent findings suggest that carbon release along subduction geothermal gradients may well be more relevant than previously thought; however, it has remained difficult to achieve steady state atmospheric CO 2 conditions over geological time scales based on current volatile cycle models. Here, we report on meta-ophicarbonate rocks in the contact metamorphic aureole of the Bergell intrusion, Val Malenco, European Alps, that reached T-P conditions of at least 650 °C at 0.35 GPa. We demonstrate by combined field evidence, geochemistry, and closed-system thermodynamic modelling that over 50% of the rock carbonate has been mobilised locally in response to reactive fluid flow upon progressive isobaric heating from 350 to >650 °C. Despite complete mineral transformation at the antigorite + calcite devolatilisation reaction, the resulting tremolite-ophicarbonate preserves the original ophicarbonate texture by olivine-chlorite clasts, representing the former antigorite-serpentinite fraction, embedded in a monomineralic tremolite matrix formed from the calcite fraction that often exceeded 50 vol%. Closed system thermodynamic modelling based on an ophicarbonate composition of 80 wt% serpentinite +20 wt% calcite reveals that rock-buffered fluid X CO2 values evolve from <0.09 to as high as ∼0.16, and the total H 2 O-CO 2 fluid fraction released may be as high as 14 wt%; values that are highly sensitive to bulk ophicarbonate composition. Major to trace element geochemistry reveals a history of peridotite melt depletion followed by ocean floor hydration and ophicarbonate formation, consistent with the ocean continent transition (OCT) setting of the mantle rocks in the Mesozoic. This is demonstrated by positive anomalies in B, U, As, Sb, Bi, and W, and by bulk rock and notably carbonate primitive mantle normalised REE patterns that are basically identical to that of calcite precipitated from Jurassic seawater except for its negative Eu anomaly. Prograde metamorphic tremolite and diopside possess enrichments notably in Sr and REE inherited from reactant calcite, as is also supported by a good match between measured and modelled silicate mineral compositions. Specific geochemical characteristics of the prograde meta-ophicarbonate rocks imply fluid mediated, open system processes. Antigorite dehydration fluid ingress, likely produced in neighbouring antigorite-serpentinites, may have shifted bulk tremolite ophicarbonate rock compositions towards higher SiO 2 /MgO ratios along with an increase in B contents and depletion in fluid mobile elements such as As, Sb, and Sr. The massive, contact metamorphic CO 2 mobilisation documented here occurred at P-T conditions that are similar to those that can be achieved in collisional orogenic settings, whose clockwise P-T-t paths are often characterised by further heating upon initial decompression. They thus evolve at large angle to devolatilisation reactions and silicate-carbonate rock-buffered fluid X CO2 isopleths, thus fostering carbon mobilisation towards metamorphic peak temperatures at moderate to low pressures (in the region of between >700 °C – 1.0 GPa and >600 °C – 0.3 GPa). Barrovian metamorphism, too, can reach T-P conditions of 800 °C – 1 GPa. Amagmatic CO 2 mobilised this way will eventually reach the atmosphere via dispersion in the groundwater table and diffuse outgassing. Despite the huge uncertainties associated with quantification of such metamorphic carbon fluxes, geological time scale global carbon cycling models should more rigorously explore the significance of these contributions. [ABSTRACT FROM AUTHOR]

We report on an unexpected effect of adhesives on the surface reconstruction of SrTiO 3. We used two types of commercially available high-temperature adhesives, the platinum (Pt) and carbon (C) pastes, to mount two identical SrTiO 3 (100) substrates onto the sample holders, respectively. Two different surface reconstructions, namely 2 × 1 and (√13 × √13)-R33.7°, were obtained using Pt and C paste under nominally identical annealing conditions in ultrahigh vacuum (UHV). We show that the same two surface reconstructions can be obtained separately with annealing in UHV and in an O 2 environment from identical substrates mounted without adhesives. Residual gas analysis of the adhesive outgassing suggests that the silicate binder in the C paste releases O 2 at high temperatures while the Pt paste does not. Due to the limited amount of O 2 that can be released from the C paste, a change of the surface reconstruction from (√13 × √13)-R33.7° to 2 × 1 was observed on the same substrate mounted with the C paste upon increasing the duration of annealing in UHV. Our study indicates that slight outgassing of certain adhesives may have a profound impact on the surface reconstruction of SrTiO 3. This finding also provides an interesting new knob to tune the surface reconstruction of SrTiO 3 in the same annealing environment. • Controlling the surface structure of SrTiO 3 is extremely important for tailoring the properties of the SrTiO 3 surfaces and interfaces with other materials for related applications. • Our study indicates that slight outgassing of certain adhesives may profoundly impact the surface reconstruction of SrTiO 3. • We provide a new method to control the surface reconstruction of SrTiO 3 with adhesive outgassing. [ABSTRACT FROM AUTHOR]

• Anthropogenic disturbances cause large shifts in dissolved carbon turnover. • River damming and agriculture modulate aquatic metabolism and CO 2 outgassing. • Dissolved carbon turnover follows the associated trajectories of biogeochemistry. • A part of dissolved carbon is cycled rapidly in karst aquatic ecosystems. • Biological carbon pump triggers overall dissolved organic carbon metabolism. Dissolved carbon (C) provides critical feedbacks to regional biogeochemical processes and global C cycling. Yet to date, the specific pathways of fluvial dissolved C turnover, particularly with human-induced shifts involved, are still poorly understood. Here, we examined dissolved inorganic (DIC) and organic C (DOC), as well as human disturbances i.e., river damming and land use in karst rivers. We show that anthropogenic activities caused unexpected shifts to dissolved C biogeochemistry. Specifically, we found that human disturbances accelerated aquatic metabolism, ultimately causing more river CO 2 generation than fixation. The extended hydrological retention by damming greatly stimulated biological utilization of dissolved C. River DOC was sourced largely from farmland and forest, while land-use fragmentation increased DOC diversity. Artificial dams and land uses intensified the transformations between DIC and DOC within karst environments. Based on these findings, we provided a process-based conceptual model regarding the rapid cycle of active C in karst waters, revealing the associated trajectories of DIC and DOC biogeochemistry. This study suggests that reducing anthropogenic disturbances essentially decelerates organic C metabolism, and therefore promotes riverine CO 2 sequestration in the context of global C neutrality. [Display omitted] [ABSTRACT FROM AUTHOR]

Hot volcanic pyroclasts can sinter, vesiculate, and outgas in concert – a combination of processes which remains poorly constrained. And yet this combination of processes can occur coincidently during deposition from pyroclastic density currents, in conduit-filling pyroclastic debris, and in tuffisites. In many of these settings, it is the sintering-driven evolution of permeability that is key to gas transport through the evolving deposit. Here, we experimentally and theoretically investigate the evolution of the permeable networks during sintering of hot fragmental volcanic systems, which are hydrous and oversaturated at the experimental conditions. Firstly, we find that vesiculation results in shutting of the inter-granular porous network as bubble growth drives expansion of the particles into one another, destroying interconnected pores. Secondly, we observe that degassing by diffusion out of the particle edge results in contraction of the vesicular particles, re-opening pore spaces between them. Therefore, we find that vesiculation, and diffusive outgassing compete to determine both the intra-fragment vesicularity and the permeability during sintering. The development of intra-fragment vesicularity directly impacts the inter-fragment pore space and its connectivity, which decreases during vesiculation and subsequently increases during diffusive outgassing, prompting complex, non-linear permeability evolution. The relative dominance of these processes is fragment size dependent; proportionally, fine fragments lose gas at a higher rate than coarser fragments during diffusive outgassing due to larger surface area to volume ratios. As the systems progress, larger fragments retain a higher proportion of gas and so attain greater vesicularities than finer ones – and therefore, the coarse fragmental pyroclasts experience a greater, yet transient, reduction in connected porosity and permeability. We suggest that where vesiculation is sufficient, it can lead to the complete loss of connected porosity and the sealing of permeable pathways much earlier than in a sintering-only system. Our results suggest that classical sintering models must be modified to account for these vesiculation and diffusive degassing processes, and that only a combined vesiculation, sintering, and diffusive outgassing model can resolve the evolution of permeability in hot clastic volcanic systems. • The physico-chemical properties of pyroclastic systems evolve even after deposition. • Simultaneous sintering, vesiculation and outgassing of pyroclasts controls system permeability. • These processes are active at different timescales for different sized pyroclasts. • Vesiculation and diffusive outgassing cause non-linear intragranular porosity evolution • Sealing of permeable pathways by sintering is more efficient when fragments also vesiculate. [ABSTRACT FROM AUTHOR]

Volatile exsolution is widely considered to be capable of generating magmatic overpressure and triggering volcanic eruptions. Despite its role as an eruption trigger, exsolution-driven overpressurisation is relatively poorly understood. Part of the problem is that thermodynamic models do not consider how the behaviour of small quantities of magma scales up to reservoir level – where variations in temperature and crystallinity become important. In contrast, many thermomechanical models focus only on magma injection, and do not consider how overpressure evolves spatially or temporally, when related to crystallisation and volatile exsolution. Here, we use Rhyolite-MELTS to track exsolution-driven overpressure during cooling for a variety of natural compositions, storage pressures, initial volatile contents and magmatic X H2O (molar H 2 O/ (CO 2 + H 2 O)). We then couple these outputs to a thermal model to determine the timescales and spatial extent of overpressurisation with varying volatile content. We find that the highest overpressures occur in magmas which are initially at their H 2 O solubility limit, with the addition or removal of H 2 O resulting in a decrease in peak overpressure. We also find that maximum overpressure decreases with the addition of CO 2 (decreasing X H2O) at typical magma storage pressures of 100–230 MPa. The higher overpressures generated at the volatile 'sweet spot' have a greater potential to trigger eruptions – or to favour their initiation by making the system more susceptible to other triggers, such as magma injection. The reduction in overpressure with increasing or decreasing initial H 2 O suggests that triggering by volatile exsolution is less likely for these magmas. Peak overpressure at the volatile sweet spot also coincides with an increased incidence of explosive eruptions at water contents ∼4–5.5 wt%. This suggests that higher magmatic overpressures may produce more explosive eruptions, by driving faster initial ascent rates and decreasing outgassing efficiency in the conduit. Our thermal modelling demonstrates that, for small magmatic systems, exsolution-driven overpressurisation can operate on timescales which are much shorter than the crustal relaxation timescale. In these cases, overpressure cannot be dissipated by a visco-elastic crustal response, and therefore has the potential to trigger a volcanic eruption. • Highest overpressure occurs for magmas initially at H 2 O solubility limit. • Overpressure increases with increasing X H2O. • Critical overpressure can be attained within crustal relaxation timescales. • High overpressures may drive faster ascent rates and influence eruption style. [ABSTRACT FROM AUTHOR]

Glacial to interglacial changes in atmospheric CO 2 are an intriguing part of carbon reorganization in the climate system and are estimated by investigating deep-water carbonate ion concentrations ([CO 3 2−]). The scarcity of studies on [CO 3 2−] in deep waters of the Indian Ocean and its role in the climate system inspired us to study the past carbonate ion variations from the eastern Arabian Sea (EAS). We analyzed B/Ca ratios, δ13C, and δ18O of epibenthic foraminifera Cibicidoides wuellerstorfi from three cores bathing in different water masses of the EAS to determine deep-water [CO 3 2−] and ventilation, spanning the Last Glacial Maximum (LGM) to the Holocene. This study reveals the existence of stored CO 2 in deep waters of the EAS during the LGM. We document two periods of rise in [CO 3 2−] in deep waters, during the deglaciation and the mid–Holocene. The rise in [CO 3 2−] during the deglaciation indicates the outgassing of stored glacial CO 2 from deep waters via the Southern Ocean and through escape via intermediate waters of the EAS. The minor rise in [CO 3 2−] during the mid-Holocene could be due to the release of CO 2 from deep water through upwelling, caused by strengthening of southern hemisphere westerly winds since 5.3 ka. • Existence of stored CO 2 in deep waters of the EAS during the LGM. • Rise in [CO 3 2−] in deep waters, during the deglaciation and the mid–Holocene. • Deglacial [CO 3 2−] rise due to outgassing of stored glacial CO 2 from deep waters. [ABSTRACT FROM AUTHOR]

In this study, two grades of high speed steel (HSS), having different carbon content and processing treatment (i.e. cryo-milling and atomization), were used as a metallic binder for NbC cemented carbides. Thermoanalytical methods were used to investigate the outgassing and sintering of the two NbC cemented carbides during heat treatment. For this mean, thermogravimetry (TG), differential scanning calorimetry (DSC) and evolved gas (EG) analysis during thermal heat treatment were carried out. The results indicated that the processing treatment has a great impact on the thermal behavior of the steel powders, which later can be traced in the thermal behavior of the compacts. Higher decarburization was traced during the thermal analysis on the powder prepared via cryo-milling compared to the one made by the atomization process. From the TG analysis of the green compacts, it was evident that intensive outgassing occurs at temperatures above 850 °C. This phenomenon is associated with the activation of several mechanism in NbC and steel above this temperature which was realized from the evaluation of the initial powders. To gain a deeper understanding on the basic reactions and the effect of carbon content on phase transformations during the thermal process, thermodynamic studies was performed using commercial software (Thermo-Calc). It was evident that decreasing the carbon content shifts the transformation temperatures (e.g. liquid formation) to higher levels. This is especially important in adjusting the sintering temperature in NbC-high speed steel system as sufficient portion of liquid phase should be presented during the sintering process in order to obtain a satisfactory sintering. [ABSTRACT FROM AUTHOR]

We present the results of electron-beam sintering of composite ceramic compacts based on alumina and titanium powders. The electron beam was generated by a plasma-cathode electron source at elevated pressure values of the fore-vacuum range. We have studied the effect of the pressed compact thickness on the sintered sample parameters. It has been established that the pressed thickness significantly affects the uniformity of parameters. The samples with the most uniform parameters were obtained for thickness values below 4 mm. At a greater thickness, the parameter non-uniformity increases considerably due to outgassing from the surface of the sintered compacts. [ABSTRACT FROM AUTHOR]

Polymeric composites are widely adopted for design and realization of spacecraft components and subsystems, due to their lightweight and thermo-mechanical properties. However, the use of such materials for aerospace operations should be carefully conceived, since the detrimental effects they may experience within the severe space environment. A typical issue to be considered is represented by the outgassing phenomena a polymeric composite suffers in ultra-high vacuum at elevated temperatures: in this harsh condition, a release of gaseous species from the material surface takes place, resulting in structural depletion and nearby components contamination. The present work describes the results of outgassing tests carried out on three typologies of widely used polymeric composites, such as epoxy matrix reinforced by carbon fiber, fiberglass and aramid fabric. The experimental behavior of these materials is analyzed with the aid of infrared spectroscopy, in order to gain knowledge about the chemical modifications that outgassing dynamics induce on the fiber-intercalated polymeric chains. The compliance to space assurance requirements – i.e., mass loss and condensed matter amounts vs. standard outgassing rates thresholds – is discussed with regard to the different functionalities each material is envisaged to accomplish, when applied onto space vehicle's exposed side. Further, in case of exceeding outgassing rate, a pre-treatment by thermal conditioning is proposed to improve the chemical stability of materials in thermal-vacuum conditions, in order to explore the feasibility of their use for aerospace applications. • Evaluate composites outgassing is mandatory for aerospace missions. • A facile low cost composites production route is proposed. • Carbon fiber composite shows acceptable outgassing rates. • Fiberglass and Kevlar composites should be screened. • A novel outgassing dynamics modeling is introduced. [ABSTRACT FROM AUTHOR]

In the last decades, together with the technological advances, the exploration of closer celestial bodies has experimented a high increasing, with a special relevance of the missions whose objective is the scientific search of life precursors. Since the birth of COSPAR (Committee on space research) in 1964, many advances have been achieved in terms of Planetary Protection, to avoid introducing terrestrial contamination in other systems, and/or come back with extraterrestrial contaminations in sample return missions. Many restrictive protocols are adopted by space missions to minimize the bacteriological, molecular and particle contaminations, and especially harder in scientific missions, where the risk of a false positive in an analysis due to terrestrial contamination is critical. These missions search for small quantities of organic material, and any trace of simple signals of C–H, C–O, C–C, C–N, etc. bonds are the target. Many of these signals are present in all the polymeric components used in a space vehicle, and any accidental or natural contamination could lead to a false positive detection of precursors of life. In this work, a new protected technology to avoid any doubt in these cases is proposed: the systematic isotopic marking of polymeric materials used in space missions. As proof of concept, polyethylene terephthalate (PET) polymers, with the same characteristics of the one used in the calibration target for the Raman Laser Spectrometer (RLS) in the ExoMars mission, were synthetized in three different ratios of deuterium marking: 0%, 35%, and 100%. In addition the calibration target of the SuperCam instrument of the Mars 2020 mission also includes a sample of PET. The polymeric characterization by Thermo-gravimetric analysis (TGA) and Differential scanning calorimetry (DSC) showed similar characteristics, in the range of commercial PET polymers. The same analytical techniques used for organic studies, on board of the ExoMars laboratory, were used for this study: Raman spectroscopy, and Gas chromatography with mass spectrometry (GC/MS). Results showed that both marked compositions could be unequivocally identified, due to the expected differences caused by the increasing of mass of the marked hydrogen atoms. The materials were subjected to the outgassing test, according to ECSS-Q-ST-70-02C standard, of mandatory compliance for every material used in a space mission following the European standards ECSS, to test the validity for space use. All materials, marked and unmarked, passed this test, and even a slight improvement in RML could be observed in the fully deuterium marked (100%) PET, probably caused by its higher weight, but further studies are needed to verify this trend. • PET polymers were subjected to three different ratios of deuterium marking for their use is scientific space missions. • The polymeric properties of new synthetized polymers were in the same range of commercial PETs. • The isotopic marking were detected by Raman spectroscopy and Gas Chromatography with mass spectrometry. • The outgassing behavior of new polymers was similar or better than the commercial PETs. [ABSTRACT FROM AUTHOR]

Rotational electron-beam mastering (REBM) systems have been studied with the aim of achieving the high data density necessary to facilitate the fabrication of next-generation optical data media, such as holographic storage. This study reports the design and testing of an ionic liquid (IL)-lubricated hydrostatic spindle system comprising an IL bearing, IL supply pump, and ionic magnetic fluid seal; and its outgassing performance under high-vacuum conditions. An inner vacuum chamber pressure of approximately 10−4 Pa was maintained during rotation of the spindle system. The outgassed products, as measured by a quadrupole mass spectrometer, were primarily generated from the air components in the lubricant IL. The non-repeatable runout in the radial direction, which is an important parameter of REBM accuracy, was 100 nm for a rotational speed of less than 130 min−1. The proposed method can be used for a 100-nm scale REBM device. • A high-vacuum-compatible hydrostatic spindle using ionic liquid was proposed. • The proposed spindle can rotate with high-accuracy and low outgassing in high-vacuum. • The outgassing from the spindle with ionic liquid circulation mechanism was investigated. • The usefulness of the spindle for an electron-beam lithography device was shown. [ABSTRACT FROM AUTHOR]

The Origins, Spectral Interpretation, Resource Identification, and Security–Regolith Explorer (OSIRIS-REx) spacecraft launched on September 8, 2016, beginning a seven-year journey to return at least 60 g of asteroid material from (101955) Bennu to Earth. During the outbound cruise, Doppler tracking of the spacecraft observed a small but measurable acceleration when the sample return capsule (SRC) was first placed in sunlight. Subsequent analysis determined that outgassing from the SRC is the most likely cause for the acceleration. This outgassing received combined engineering and scientific attention because it has potential implications both for spacecraft navigation performance and for contamination of the collected samples. Thermal modeling, laboratory studies of SRC materials, and monitoring of the acceleration are all consistent with H 2 O as the main component of the outgassing. Dedicated, in-flight campaigns continued to expose the SRC to sunlight until the acceleration dropped to the acceleration noise floor. Any residual amounts of H 2 O outgassing are not considered to be a hazard with regards to mission operations or pristine sample acquisition. The sample stow procedure has been updated to ensure that no direct line of site exists between any residual outgassing and the samples during future operations. Similar outgassing of the Stardust SRC probably also occurred. No adverse contamination of Stardust samples was observed that could be associated with this process. Future missions that use similar reentry vehicles should consider procedures to test for and, if necessary, mediate such outgassing after launch. • OSIRIS-REx accelerated slightly when sunlight hit its sample return capsule (SRC). • Outgassing from the SRC is the most likely cause of the acceleration. • Thermal modeling, lab studies, and spacecraft monitoring are all consistent with H 2 O outgassing. • Outgassing of remaining H 2 O is not a hazard to mission operations or pristine sample acquisition. • Similar outgassing of the Stardust SRC probably also occurred. [ABSTRACT FROM AUTHOR]

The singular mechanism of water adsorption in carbon pores has been roughly elucidated due to the intense research conducted in this field in the last years. Thus, it has been demonstrated that the surface chemistry of the carbon material plays a crucial role in the initialization of the water sorption process. However, the potential changes induced in the surface properties, and therefore in the water isotherm, during the outgassing of the sample prior to the water sorption measurement, have not been addressed yet. On the contrary, the same preparation protocol used for the analysis of non-associating simple fluids (N 2 , CO 2 , Ar) is commonly followed. Aiming at filling this gap, two activated carbons with different textural and surface properties have been outgassed under different conditions of time and temperature and subsequently characterized by H 2 O, N 2 and CO 2 isotherms and thermogravimetric analysis. The obtained results show that the optimal conditions of the outgassing treatment are not necessarily the same for all the adsorbates tested and will highly depend on the characteristics of the sample. In this regard, the recommended outgassing temperature for water sorption isotherms of nanoporous carbons seems to be lower than for other adsorbates and may not exceed 100 °C. Image 1 [ABSTRACT FROM AUTHOR]

Hydrogen outgassing from a metal surface and a coated metal surface was visualized by two-dimensional mapping of hydrogen ions desorbed upon scanning electron beam irradiation. The samples used were stainless steel covered with a dense chromium oxide layer, and a reference surface of stainless steel. The coating layer was made by using the segregation phenomenon of the metal. Outgassing of hydrogen was detected from the holelike defects on the treated surface. However, hydrogen was not released from all the holelike defects seen in the SEM image. The outgassing positions were positions without chromium, but not all areas without chromium and/or oxygen coincided with outgassing positions. Unlabelled Image • Surface hydrogen was visualized by desorption induced by electronic transition; DIET. • Hydrogen on coated and non-coated stainless steel were visualized in one DIET image. • Hydrogen density was decreased by chromium oxide coating made by surface segregation. • Hole like defects in chromium oxide coating release hydrogen. • Not all of the defects found in the SEM image release hydrogen. [ABSTRACT FROM AUTHOR]

A vacuum vessel which is the first confinement barrier of Tokamak fusion reactor should have numerous in-vessel components. Since those components are to be exposed to the plasma under ultrahigh vacuum condition and should be maintained during Tokamak operation, a threaded connection of vacuum vessel and in-vessel components is necessary. The threaded connection of stainless steel with the components causes difficulties during assembly or disassembly due to the large friction coefficient of stainless steel. To resolve this issue, anti-seize coating that does not affect the mechanical property, thermal stability, and outgassing rate of the threaded insert needs to be developed. In this study, adhesion, porosity, outgassing, and friction wear tests for a cyanide copper electrodeposited surface on 316 L austenitic stainless steel test coupons were performed to validate the high level of confidence in the performance of a cyanide copper electrodeposited threaded insert. The validation tests results showed that cyanide copper electrodeposition for anti-seizing could be applied to the 316 L stainless steel threaded insert in the vacuum vessel and in-vessel components of the Tokamak fusion reactor. [ABSTRACT FROM AUTHOR]

The results of a study of the chemical composition, vacuum and thermal properties of boron carbide ceramics, which is planned to be used in ITER diagnostic ports, are presented. The measured boron carbide content in sintered and hot pressed ceramics is 99,0÷99,7%, they do not contain unauthorized impurities, which in accordance to ITER requirements. The outgassing rate of sintered and hot pressed boron carbide produced by Virial Ltd meets the requirements of the ITER Vacuum Handbook. Sintered ceramic is cheaper than hot pressed, and it is produced in large volumes, which it would be preferable for use in ITER ports, but with its massive use may create a significant gas load on the vacuum system that requires accurate analysis and outgassing tests on all candidated ceramics. [ABSTRACT FROM AUTHOR]

Remote maintenance in fusion machines such as JET (Joint European Torus) and ITER (International Thermonuclear Experimental Reactor) relies on sliding interfaces such as bolted joints. Experience in JET, where removal torques much higher than installation values with uncoated bolts is commonplace, led to the installation of experimental bolted assemblies in 2015: the first of its kind in JET. These assemblies included some 660B stainless steel ITER Blanket-specific bolts with a solid sputtered coating of MoS 2 as part of an ITER-funded project known as CHEF (Coating and Humidity Experiments on Fasteners). CHEF also includes two ex-vessel activities. The first is a characterisation of the coating fundamental properties including outgassing, friction, wear and sensitivity to humidity: on flat sample discs. The second is the measurement of the coating performance on bolted assemblies subjected to a sequence of tests: initial tightening cycles, thermal vacuum exposure, environmental exposure (high humidity and high temperature), repeated thermal vacuum exposure, and final tightening cycles. This sequence approximates to a possible operation cycle of ITER bolted joints which receive an accidental humidity exposure during operation. [ABSTRACT FROM AUTHOR]

The Eastern Boundary Upwelling System off northwest Africa is among the most productive regions of the ocean. In 2019, two merchant ships equipped with an underway CO 2 system sampled the region following exactly the same track from 10°N to 36°N. We determine the sources and sinks of CO 2 and the seasonal cycle along the track. A weak permanent upwelling (WPU), a permanent upwelling (PU) and an open ocean regions are identified. The WPU (26°N to 33°N) is a source of CO 2 in summer and autumn, and a sink of CO 2 in winter and spring. Thermodynamic warming and cooling processes mainly drive the CO 2 variations in this region. The PU (20°N to 26°N) is a sink of CO 2 in spring and a source of CO 2 in other seasons. This region is the most productive and exhibits the largest variability of the CO 2 flux. The supply of CO 2 from subsurface waters dominate over the carbon uptake by biology, which leads to a strong outgassing, especially in winter and autumn. A sink of CO 2 occurs in spring only in the PU. Near Cape Blanc (20°N) in July 2019, a source of CO 2 is observed around 20°N within ± 1° of latitude and becomes a sink of CO 2 a few days later when the ship samples back the same area. South of 18°N, out of the influence of the coastal upwelling, the region is a sink of CO 2 in winter only and the region is mainly controlled by physical processes. Using voyages from 2010 to 2022, seawater f CO 2 significantly increases at a rate ranging from 1.82 μatm yr−1 to 2.10 μatm yr−1 close to the atmospheric increase. This is associated with a pH decrease between 0.0016 and 0.0022 yr−1. Nevertheless, there is no clear trend of the CO 2 flux in any region. • The NW African permanent upwelling (20-26°N) is a source of CO 2 except in spring. • The Weak Permanent Upwelling is a source of CO 2 in summer and autumn. • Surface pH has decreased at a rate of 0.002 unit yr−1 from 2010 to 2022. [ABSTRACT FROM AUTHOR]

• R&D work on HHLT facility for ITER large vacuum components is successful in China. • A satisfying result (lower than 2.69×10−10 Pa*m3/s) in the 1st HHLT on the shield block full-scale prototype. • H 2 O and H 2 outgassing is the major factor impacting the performance of HHLT facility at different temperatures. • The facilities' performance was improved by at least one order of magnitude after adopting outgassing-removal measures. • HHLT results of 50 shield blocks with the improved facilities are better and stable. China Domestic Agency (DA) will provide ITER with 220 shield blocks (SB) which are important, large, and actively water-cooled components in ITER vacuum vessel, their leakage rate shall not exceed 2.69 × 10 − 10 Pa · m 3 / s in hot helium leak tests (HHLT) at 250±20 °C. The HHLT work started with developing a HHLT facility and manufacturing a SB full-scale prototype (FSP). The result showed the FSP could satisfy ITER's requirement at 235 °C. H 2 outgassing from stainless steel surfaces is the main factor that impacts both the background leakage rate and sensitivity of the testing system in hot testing cases. Hydrogen-removal measures were taken to improve the facility performance, and a new facility was built. A better facility performance came out at 250 °C rather than 235 °C, the background leakage rate decreased by one order of magnitude while the system sensitivity increased by two orders of magnitude. The background is at 10−10 Pa.m3/s and 10−9 Pa.m3/s level at room temperature (RT) and 250 °C, respectively, while the system sensitivity is at 10−12 Pa.m3/s and 10−11 Pa.m3/s level at the two temperatures. With the two facilities, series HHLTs have been carried out on 50 SBs covering two types, with all results complying with ITER requirements. [ABSTRACT FROM AUTHOR]

This study investigated the feasibility of using a ferrite (HF70) as a damper for a strong higher order mode (HOM) excited by vacuum components of the SuperKEKB collider. The measurement results confirmed that the new material HF70 has absorption parameters similar to those of IB004, which is the material currently used in the SuperKEKB Simulations and measurements confirmed that the excited HOM can be absorbed without adversely affecting the beam by placing HF70 in the antechamber of the beam pipe. To suppress the temperature rise due to HOM, a method to braze HF70 to a copper cooling block was established. The measurement results of outgassing rate, secondary electron yield rate, and dust generated from the surface of HF70 indicated that the proposed method did not cause any negative effects. Further, HF70 was proven to be effective in the SuperKEKB by fabricating a prototype beam pipe with HF70 attached and performing a successful baking test. [ABSTRACT FROM AUTHOR]

Abstract In this study, an ionic liquid (IL)-based magnetic fluid (MF) (IMF; IL-based MF) and dispersant was synthesized to create MF seals for rotational mechanisms in high-vacuum chambers, such as those in rotational electron beam mastering systems. The synthesized dispersant dispersed magnetite nanoparticles in pyridinium ionic liquid that is stable under magnetic fields. The outgassing from the IMF was investigated using a quadrupole mass spectrometer during a sliding test under high-vacuum conditions with a pressure of 10−6 Pa. The fragmentation pattern of the outgassing from the IMF was very similar to that of the base IL. Pollution-causing fragments were not detected under vacuum conditions on the order of 10−9 Pa. On the basis of our findings, we anticipate that the IMF is suitable for use in MF seals required in clean, high-vacuum conditions. Highlights • An ionic liquid-based magnetic fluid (IMF) using a new dispersant was synthesized. • The IMF generated low outgassing under friction in high-vacuum conditions. • Few fragments from the new dispersant were detected by Q-mass. • The usefulness of the IMF under high-vacuum conditions was shown. [ABSTRACT FROM AUTHOR]

Abstract In this paper, a new calibration apparatus has been developed for gas micro-flow calibration. The apparatus employs both the constant volume method and the constant conductance method. The calibration range from 10−1 to 10−13 Pa·m3/s, and the combined standard uncertainty is 1.2%∼1.8%. When calibrating extremely low gas flow rate, the non-evaporable getter pump is used to reduce the effect of chamber wall outgassing on the measurement results, so that the lower limits of the constant volume method and constant conductance method are extended to 10−10 Pa·m3/s and 10−13 Pa·m3/s, respectively. Then a method for measurement of orifice conductance is proposed, the on-line precise measurement of the orifice conductance is realized; the consistency of flow measurement results by constant volume and constant conductance methods is better than 1.3%, then compared with the same standard leak was calibrated in both constant conductance method of the calibration apparatus and the constant pressure gas micro-flow calibration apparatus of the laboratory, and the deviation of those results was less than 1%. Highlights • The gas micro-flowmeter is combined with the constant volume and the constant conductance methods. • The constant volume chamber adopts NEG pump static pumping mode, the lower limit extended to 2×10−13 Pa·m3/s. • The method for measurement of orifice conductance is proposed, and the curve of orifice conductance was obtained. • The new apparatus is consistent with the results of the constant pressure calibration apparatus. [ABSTRACT FROM AUTHOR]

Abstract Ocean ridges are one of the primary connections between Earth's mantle and surface. Therefore, understanding the evolution of ocean ridge processes through Earth history is important for understanding how Earth's surface and mantle have evolved. We combine an analytic model of mantle convection with a petrologic model of mantle melting in the presence of CO 2 to compute the mantle temperature, plate speed, melt production, and CO 2 outgassing flux at ocean ridges for the past 4 billion years. We explore a large suite of realistic mantle and lithospheric parameters to map out a full range of possible thermal histories. Our results show that in order to satisfy thermal constraints, the Earth must have started in a sluggish-lid mode of plate tectonics and transitioned to an active-lid mode. Furthermore, we show that plate speed and CO 2 outgassing flux do not necessarily scale with mantle temperature, and that it is possible to reach present-day mantle temperatures and plate speeds with a simple force balance that does not invoke any feedbacks (e.g. grain size evolution, dehydration stiffening) or a fully stagnant-lid mode of convection in the Precambrian. The solutions show a range of evolutionary behaviors depending on the parameters chosen. The transition from sluggish- to active-lid can be smooth, abrupt, or somewhere in between. A smooth transition is difficult to distinguish from a purely active-lid evolutionary path based on temperature, plate speed, melt production, and CO 2 outgassing flux. In contrast, an abrupt transition leads to a large increase in the average plate speed with a corresponding increase in melt production and CO 2 outgassing flux. As an abrupt transition would have a much larger effect on CO 2 outgassing and melt production than a change in ridge length, we investigate the impact of rapidly changing plate speeds and do not consider changes in ridge length. Finally, we show that carbon recycling is required for a large part of Earth history in order to explain present-day CO 2 outgassing. Our model highlights the importance of understanding the style of mantle convection when calculating melt production and volatile fluxes through Earth's history. Highlights • An analytic model of convection is used to calculate the mantle's thermal history. • A simple change in force balance can lead to sluggish-lid tectonics in the Archean. • CO 2 outgassing and melt production depend on the style of plate tectonics. • CO 2 outgassing and melt production do not necessarily scale with mantle temperature. • Recycling of CO 2 is required to explain modern CO 2 outgassing rates. [ABSTRACT FROM AUTHOR]

Abstract A novel method to evacuate large bins of lunar regolith simulant for deep drilling tests was proposed in the current work. This method can be used to simulate a vacuous lunar regolith environment to a maximum penetration depth of 2 m. An experimental apparatus was built and is composed of a vacuum chamber, a specially designed regolith container and a vacuum pumping system. A pressure on the order of 10 Pa could be reached with the 4.3 m3 vacuum chamber when compacted lunar regolith simulant with a volume of 0.4 m3 was loaded. A theoretical model to predict vacuum degree was proposed basing on the viscous flow theory. Evacuation experiments with or without lunar regolith simulant inside the chamber were performed and the outgassing properties of lunar regolith simulant was experimentally studied. The results show that the outgassing rate of the lunar regolith simulant was about 107 times to that of the electro-polished stainless-steel. Highlights • A novel method to evacuate large bins of lunar regolith simulant was proposed. • A theoretical model to predict vacuum degree variation was proposed. • The outgassing rate of a lunar regolith simulant was experimentally studied. [ABSTRACT FROM AUTHOR]

Highlights • The Bi-Bi 2 O 3 -TiO 2 -C composite was first prepared and characterized. • The capturing capacity of the composite was calculated about 504.0 ± 19.5 mg/g. • The proposed mechanism of the iodine capturing reaction on the composite was investigated. Abstract The Bi-Bi 2 O 3 -TiO 2 -C composites were prepared by a sol-gel method and investigated for capturing iodine-129 (129I) in off-gas producing from spent fuel reprocessing. Firstly, the optimal process conditions were operated through the orthogonal experiments, showing that the capturing capacity of the optimal composite was calculated about 504.0 ± 19.5 mg/g, which is approximately 2.0-fold higher than that of the commercial silver-exchanged zeolites (AgX). Secondly, the structure and morphology of the Bi-Bi 2 O 3 -TiO 2 -C composite were characterized, suggesting that the Bi is regularly spherical in the shape, coating by the Bi 2 O 3 , TiO 2 and amorphous carbon. Finally, the mechanism for the iodine adsorption in the Bi-Bi 2 O 3 -TiO 2 -C system was revealed, demonstrating that the iodine was captured by physisorption and chemisorption. [ABSTRACT FROM AUTHOR]

Graphical abstract Abstract The aim of this work is a technical review about Quartz Crystal Microbalance (QCM) sensors used in space missions, i.e. Space Shuttle flights, i.e. NASA Space Transportation System (NASA STS) and satellite missions, that aimed at monitoring the contamination generated by outgassing processes of materials onboard satellites and sensitive payloads. The contamination processes are critical for scientific instrumentation (e.g. optics, telescopes, detectors) because scientific measurements and performances can be jeopardized or worsened by uncontrolled contamination. This issue has been addressed by the space agencies, e.g. NASA, ESA and JAXA that have implemented many different studies to monitor the material outgassing and degradation in space environment. During the past years, the QCM sensors have become the baseline solution for measuring material outgassing and characterizing the on-orbit contamination environment. This work summarizes the main QCM applications in Space and their findings, providing an overview of the sensors' performances in terms of stability, power, data rate, measurement accuracy and resolution. Different QCM technologies will be compared highlighting the advantages of their use for the next space missions and instrumentations that require an accurate monitoring of contamination environment. In particular, due to more severe contamination requirements for next payloads and instrumentations, QCM sensors would be useful to estimate the cleanliness degree by evaluating the induced contamination and degradation on sensitive instrumentations. [ABSTRACT FROM AUTHOR]

Abstract The combination of steam reforming and HT-PEMFC has been considered as a proper set up for the efficient hydrogen production. Recycling anode off-gas is energy-saving strategy, which leads to enhance the overall efficiency of the HT-PEMFC. Thus, the recycling effect of anode off-gas on steam-reforming performance needs to be further studied. This paper, therefore, investigated that the combustion of anode off-gas recycled impacts on the steam reformer, which consists of premixed-flame burner, steam reforming and water-gas shift reactors. The temperature rising of internal catalyst was affected by lower heating value of fuels when the distance between catalyst and burner is relatively short, while by the flow rate of fuels and the steam to carbon ratio when its distance is long. The concentration of carbon monoxide was the lowest at 180 °C of LTS temperature, while NG and AOG modes showed the highest thermal efficiency at LTS temperature of 220–300 °C and 270–350 °C, respectively. The optimum condition of thermal efficiency to maximize hydrogen production was determined by steam reforming rather than water gas shift reaction. It was confirmed that the condition to obtain the highest thermal efficiency is about 650 °C of steam reforming temperature, regardless of combustion fuel and carbon monoxide reduction. The difference of hydrogen yield between upper and lower values is up to 1.5 kW as electric energy with a variation of thermal efficiency. Hydrogen yield showed the linear proportion to the thermal efficiency of steam reformer, which needs to be further increased through proper thermal management. Highlights • The combustion characteristics of AOG and NG are compared. • The temperature distribution of the catalyst layer is analyzed according to FDR. • The optimum hydrogen production plan of AOG and NG utilization are confirmed. • Experimental analysis can be utilized to enhance the performance of SR and LTS. [ABSTRACT FROM AUTHOR]

Highlights • Ni-doped Fe(OH) 2 (s) – spinel transformation process at low temperatures. • 99Tc(VII) reduced to 99Tc(IV) and incorporated into produced spinel simultaneously. • Fe(OH) 2 (s) can remove both Cr and 99Tc from an off-gas simulant. Abstract Technetium-99 (99Tc) incorporation within stable spinel phases is a novel method for 99Tc removal and immobilization from waste streams. In this study, transformation of Ni-doped Fe(OH) 2 (s) to spinel minerals, e.g. trevorite (NiFe 2 O 4), is explored as a method for removing 99Tc from Hanford Waste Treatment and Immobilization Plant (WTP) primary off-gas waste stream simulant. The Fe(OH) 2 (s) transformation process was found to reduce 99Tc(VII) to 99Tc(IV) and incorporate reduced Tc(VI) into the produced spinel simultaneously. Nickel doping was applied in the mineral transformation to inhibit potential reoxidation of 99Tc(IV). Solid phase characterization by XRD and XANES confirmed the formation of nickel substituted ferric-spinel, and suggest incorporation of 99Tc(IV) in the final spinel. Furthermore, in the primary off-gas stream, which contains both redox-sensitive contaminants Cr(VI) and 99Tc(VII), results from solution analysis and solid digestion indicate that nearly 100% Cr and over 80% 99Tc can be simultaneously removed by adding Fe(OH) 2 (s) to solution with a solid to solution ratio of 5 g/L under near neutral and alkaline conditions. The 99Tc removal approach developed herein provides an alternative treatment method to eliminate the proposed recycle process of the off-gas waste stream, which ultimately can reduce WTP mission cost and operation time. [ABSTRACT FROM AUTHOR]

Highlights • Antenna performance is described with coefficients of transmission and dissipation. • Effect of RF conditioning on the antenna performance is quantitatively analyzed. • Outgassing rate per dissipated power decreases by the RF conditioning. • A new figure-of-merit is defined to evaluate degree of the RF conditioning. • Antenna performance is almost doubled in well-conditioned stage. Abstract RF conditioning is conducted to improve coupling and current drive performance of the comb-line antenna which is to excite fast wave in lower hybrid resonance frequency range in Versatile Experiment Spherical Torus (VEST). It has been observed that considerable outgassing, power dissipation and high reflection take place while diminishing transmitted power with poor reproducibility without the RF conditioning process which cleanses antenna surface by RF surface heating. Outgassing source during the RF conditioning is identified mainly as water vapor. A new dimensionless figure-of-merit to evaluate degree of the RF conditioning is defined with dissipated power and outgassing rate by analyzing experimentally observed RF conditioning data. Optimum performance of the antenna with low figure-of-merit (5 × 10−9) is achieved after conditioning for 3 days a week (∼40 shots) at less than 10 kW of input power. Coefficients of transmission, reflection, and dissipation reach to about 80%, 2%, and 18%, respectively indicating almost doubled antenna performance. Introduced new figure-of-merit provides a quantitative basis for antenna conditioning in order to improve antenna performance. [ABSTRACT FROM AUTHOR]

Abstract Extinction and delayed recovery during the end-Permian extinction and Early Triassic has been linked to environmental instability brought on by volcanic outgassing and greenhouse conditions, but the relative importance of the myriad of environmental stressors at this time on recovery dynamics is not well understood. Previous workers have documented both overall delayed biotic recovery for the entirety of the Early Triassic, but also incipient recoveries that appear to occur relatively early after the initial extinction event. Here, we explore the patterns of extinction and recovery using several metrics of ecological complexity in marine benthic communities using a global dataset, and compare several multiple regression models to determine which set of abiotic factors best predicts extinction and recovery dynamics. We additionally test the importance of temporal scale of analysis in interpretations of recovery dynamics and modeling results, by including analyses at the epoch, stage, and substage scales bracketing the interval of extinction and recovery. We find differences in mode of recovery between the ecological metrics analyzed, with some metrics exhibiting an Early Triassic recovery lag, while others recover continuously or immediately following the initial extinction event. We also find evidence of a global 'Dienerian minimum', with overall levels of community complexity significantly lower than earlier Griesbachian communities, suggesting a synchronous disturbance to the progression of recovery at this time. The regression model with δ18O apatite mean values as the response variable is most often found to be the best-fit model across all time scales analyzed, though proxies of rock record fidelity and paleontological sampling effort become more important in finer timescale analyses, likely due to dwindling sample numbers. Out of the models tested, these results suggest that global ocean temperatures best predict patterns of extinction and recovery across several ecological metrics, and that thermal episodes during the initial extinction event and subsequently in the Early Triassic recovery period significantly suppressed benthic marine community health. [ABSTRACT FROM AUTHOR]

Abstract Nanofluidic channels with a depth of ∼100 nm were developed as a leak element, where the fluidic channels were etched on silicon wafer by reactive ion etching and then enclosed by direct silicon bonding. Instead of the Torr-seal gluing method, a tight lamination between the chip and the vacuum flange was achieved using indium gasket sealing, eliminating the influence of Torr-seal outgassing. Two leak elements with different amount of parallel channels were fabricated and their values were characterized by the difference method. The results demonstrate that the conductance of the leak elements behave in reasonable agreement with their theoretically calculated conductance with relative errors of approximately 4.9% and 42.7%, respectively. The gas flow through these leak elements realizes molecular flow at pressures ranging from high vacuum up to 105 Pa for helium, argon, and nitrogen and can therefore be used as predictable leak elements for any gas. Highlights • Nanofluidic channels with a depth of ∼100 nm are developed as a leak element and enclosed by direct silicon bonding. • A new leak element is packaged with an indium gasket to eliminate the influence of Torr-seal outgassing. • The conductance of the two leak elements is measured based on difference method. • The gas flow through the leak element is molecular flow range up to 105 Pa for helium, argon, and nitrogen. [ABSTRACT FROM AUTHOR]

Spontaneous self-heating and off-gassing of wood pellets during storage is well-recognized problem. The reason for the phenomena is be autoxidation of fatty/resin acids in the pellets material. Two antioxidants, TBHQ (tert-Butylhydroquinone) and PG (propyl gallate), have been used as additives during pellets production in order to investigate how effective these antioxidants are in blocking autoxidation. Off-gassing of volatile aldehydes, CO and CO 2 from wood-pellets and depletion of O 2 during storage at room temperature in two different scales of closed storage systems were investigated and antioxidant fortified pellet batches and a reference batch without additive were compared. The results show that TBHQ is an efficient antioxidant at a low concentration (0.5%) in blocking autoxidation of fatty/resin acids in wood pellets. The CO emissions are reduced between 72 and 90% depending on the pellets temperature. Some of the fatty acids are almost intact in the samples with TBHQ compared to reference sample; showing that TBHQ blocking degradation by autoxidation of those fatty acids. For PG, autoxidation has not been blocked. The total amount of emitted aldehydes are 77% less than in pellets made with antioxidants as compared to the reference pellets, showing that TBHQ is acting as inhibitor in the autoxidation processes. [ABSTRACT FROM AUTHOR]

A compilation of foraminiferal stable isotope measurements from southern high latitude (SHL) deep-sea sites provides a novel perspective important for understanding Earth's paleotemperature and paleoceanographic changes across the rise and fall of the Cretaceous Hot Greenhouse climate and the subsequent Paleogene climatic optimum. Both new and previously published results are placed within an improved chronostratigraphic framework for southern South Atlantic and southern Indian Ocean sites. Sites studied were located between 58° and 65°S paleolatitude and were deposited at middle to upper bathyal paleodepths. Oxygen isotope records suggest similar trends in both bottom and surface water temperatures in the southern sectors of the South Atlantic and in the Indian Ocean basins. Warm conditions were present throughout the Albian, extreme warmth existed during the Cretaceous Thermal Maximum (early-mid-Turonian) through late Santonian, and long-term cooling began in the Campanian and culminated in Cretaceous temperature minima during the Maastrichtian. Gradients between surface and seafloor δ 18 O and δ 13 C values were unusually high throughout the 11.5 m.y. of extreme warmth during the Turonian-early Campanian, but these vertical gradients nearly disappeared by the early Maastrichtian. In absolute terms, paleotemperature estimates that use standard assumptions for pre-glacial seawater suggest sub-Antarctic bottom waters were ≥21 °C and sub-Antarctic surface waters were ≥27 °C during the Turonian, values warmer than published climate models support. Alternatively, estimated temperatures can be reduced to the upper limits of model results through freshening of high latitude waters but only if there were enhanced precipitation of water with quite low δ 18 O values. Regardless, Turonian planktonic δ 18 O values are ~1.5‰ lower than minimum values reported for the Paleocene-Eocene Thermal Maximum (PETM) from the same region, a difference which corresponds to Turonian surface temperatures ~6 °C warmer than peak PETM temperatures if Turonian and Paleocene temperatures are estimated using the same assumptions. It is likely that warm oceans surrounding and penetrating interior Antarctica (given higher relative sea level) prevented growth of Antarctic ice sheets at all but the highest elevations from the late Aptian through late Campanian; however, Maastrichtian temperatures may have been cool enough to allow growth of small, ephemeral ice sheets. The standard explanation for the sustained warmth during Cretaceous Hot Greenhouse climate invokes higher atmospheric CO 2 levels from volcanic outgassing, but correlation among temperature estimates, proxy estimates of p CO 2 , and intervals of high fluxes of both mafic and silicic volcanism are mostly poor. This comparison demonstrates that the relative timing between events and their putative consequences need to be better constrained to test and more fully understand relationships among volcanism, p CO 2 , temperature ocean circulation, Earth's biota and the carbon cycle. [ABSTRACT FROM AUTHOR]

Magmatic-hydrothermal fluids transport chalcophile metals to the atmosphere as volcanic gases; and to the crust, where they may play a role in the formation of ore deposits. Global volcanic gas datasets show considerable variability in the flux and composition of metals outgassed between volcanoes, but the controls on this variability are unclear. Magmatic chloride is a key ligand for metal transport but magmatic water dominates the exsolved fluid reservoir into which metals partition during crystallisation and decompression. Here we develop models simulating decompression-driven degassing ('first boiling') and isobaric crystallisation-driven degassing ('second boiling') of magmas to show that while moderate concentrations of chlorine are essential for metal partitioning into the magmatic fluids, magmatic water contents have the greatest potential to control the mass yield of metals carried by exsolving fluids. Our models explain why water-rich magmatic-volcanic systems like Mount Etna (Italy) deliver the largest mass fluxes (per unit of degassing magma) of metals to the atmosphere, whereas relatively dry magmatic-volcanic systems like Yasur (Vanuatu) deliver the smaller mass fluxes. Our results establish the important role of magmatic water in generating large reservoirs of metal-rich aqueous fluids in the shallow crust. • Model describing trace metal partitioning into an exsolved magmatic volatile phase. • High magma chlorine contents generate high metal concentrations in MVPs. • High magmatic water contents maximise trace element fluxes in the MVP. • Isobaric fractionation at depth is a major control on chalcophile volatilisation. [ABSTRACT FROM AUTHOR]

• Isothermal thermal decomposition of AlH 3 /hydrogen absorbents was studied. • The outgassing amount of AlH 3 /hydrogen absorbents was obtained. • The thermal decomposition kinetics of AlH 3 /hydrogen absorbents was obtained. • The mechanism function of AlH 3 /hydrogen absorbent was obtained. • The material with the strongest hydrogen absorption ability. In this article, the isothermal decomposition dynamics research instrument was used to investigate the interaction between three hydrogen absorbents and AlH 3 , including C 60 , C 70 , and 1,4-bis (phenylethynyl) benzene (DEB). The gas volumes emitted by AlH 3 , AlH 3 /C 60 , AlH 3 /C 70 , and AlH 3 /DEB during the 48 h vacuum stability experiment were 2.85, 2.41, 1.92 and 2.02 mL/g, respectively. The isothermal thermal breakdown of the three materials was investigated simultaneously at 333–393 K. The isothermal thermal decomposition kinetic parameters of AlH 3 /C 60 , AlH 3 /C 70 , and AlH 3 /DEB were determined using the Arrhenius and model-fitting method by using the pressure–time curve of the decomposition and release gas of the mixed sample of AlH 3 and three hydrogen absorbents. AlH 3 /C 60 , AlH 3 /C 70 , and AlH 3 /DEB had activation energies of 118.2, 116.9, and 116.8 kJ·mol−1, respectively and pre-exponential factors of 20.49, 20.16, and 20.19, respectively. By using XRD and TEM, the thermal breakdown products were examined. [ABSTRACT FROM AUTHOR]

The article describes the procedure for measuring the specific emission rate of volatile hydrocarbon compounds from cured adhesives. The internal atmosphere of vacuum devices with adhesive joints is determined mainly by gas emission from adhesive seams. The use of getters allows the removal of active gases, but all types of getters poorly absorb hydrocarbon compounds, which create the internal atmosphere of a vacuum device. Therefore, it is necessary to use adhesives with low emission of volatile hydrocarbon compounds to assemble such devices. The chromatographic method has a high sensitivity specifically for hydrocarbons, it allows you to quickly and easily identify volatile hydrocarbon compounds released by adhesive and determine the kinetic parameters of this process. This makes the chromatographic method convenient for express analysis of gas evolution from adhesives intended for mounting the internal parts of vacuum devices. • The emission of volatile hydrocarbon compounds degrades the vacuum in devices. • The chromatographic method is convenient to determine the specific gas emission rate. • The proposed method allows to predict the residual atmosphere of vacuum devices. [ABSTRACT FROM AUTHOR]

Earth's atmosphere, crust and mantle have evolved together through continuous geochemical exchange throughout Earth's history. Constraints on the transport of volatile elements and compounds between these reservoirs are crucial for understanding how Earth could have stayed habitable for extended periods of time. Here we present a new forward model of He, Ne and Ar in the mantle, crust and atmosphere. We explore concentrations of noble gases at the end of accretion, bulk silicate Earth K/U ratios, crustal growth scenarios, and upper mantle processing rates throughout Earth's history. We search for parameter combinations that simultaneously satisfy observational constraints on present-day mantle 4He/3He and 40Ar/36Ar (sensitive to mantle outgassing and continental crust growth, which depletes the mantle of U, Th and K), atmospheric 20Ne/22Ne (which tracks the mix of outgassed vs. delivered Ne in the atmosphere), and atmospheric 40Ar/36Ar in the past and today (sensitive to volatile delivery, mantle outgassing and crustal growth). Leveraging this intertwined set of noble gas abundances and isotopic compositions yields new constraints on initial noble gas abundances in the mantle and on the proportions of atmospheric volatiles originating from delivery by impact degassing, mantle outgassing, and degassing of the continental crust. We find that atmospheric Ar isotopic evolution is primarily sensitive to the mantle processing rate history; the atmospheric Ar isotopic record should therefore not be used to reconstruct continental crust growth, but instead provides valuable insights into mantle processing rates. Our model predicts a measurably low 20Ne/22Ne ratio of ∼9.7 in Archean atmospheric samples. Most of atmospheric primordial 36Ar was directly delivered by chondritic bodies and not transferred to the atmosphere during an intense early episode of mantle outgassing. Nitrogen delivered by impact degassing could account for the present-day atmospheric nitrogen inventory. • We present a new forward model of He, Ne and Ar in the mantle, crust and atmosphere. • Atmospheric Ar isotopic evolution is primarily sensitive to mantle outgassing history. • The paleo-atmospheric Ar record cannot distinguish among crustal growth models. • Most of atmospheric primordial 36Ar was delivered by chondritic materials. • Chondritic delivery could account for the nitrogen budget of the atmosphere. [ABSTRACT FROM AUTHOR]

Thermal insulation performance and service life of vacuum insulation sandwiches depend significantly on the internal residual gas pressure. Degradation of the vacuum can lead to a dramatic increase in thermal conductivity, so the initial internal pressure should be kept as low as possible during fabrication. In this paper, the evacuation and outgassing of vacuum insulation sandwiches are studied by modeling and experimental methods. A modified pump-down model for vacuum insulation sandwiches, called the recombination-dissociation-limited model, is proposed based on diffusion, recombination, and dissociation. The results show that the recombination and the dissociation of hydrogen on the inner surface have a hysteresis effect on the evacuation process, which explains well that the pressure inside the device remains above the ultimate pressure of the vacuum system after packaging. The experimentally measured evolution of the pressure and outgassing rate in the vacuum insulation sandwiches agree well with the calculated results. The simulation analyses the effects of temperature, pump-out port size, and ultimate pressure on evacuation efficiency. It provides a theoretical basis for predicting the dynamic pressure evolution during high vacuum packaging and selecting effective parameters in the packaging process. • A modified pump-down model for vacuum insulation sandwiches is proposed. • Hysteresis mechanism of high vacuum packaging processes under readsorption effect. • Prediction of the dynamic evolution of pressure in high vacuum packaging processes. • Methods for improving the efficiency of high vacuum packaging. [ABSTRACT FROM AUTHOR]