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LiNiO 2 -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., (© 2023 Wiley-VCH GmbH.)

Dielectric materials with high surface electric insulation strength are in great demand in a high-power space solar cell array (SSCA). A moderately conductive surface is favorable to inhibit charge accumulation and mitigate electric field distortion, thus improving the surface flashover voltage. Although numerous modification methods have been proposed to achieve this goal, the facile, efficient, scalable, and environmentally friendly modification strategy remains a critical challenge to date. Considering the excellent charge modulation ability of ZnO and its mild preparation conditions, a facile and economical hydrothermal strategy was proposed to fabricate in situ a durable poly(ether imide)/zinc oxide (PEI/ZnO) coating with a high charge decay rate. The blooming flower-like ZnO in the coating is proved to play a key role in enhancing lateral charge dissipation on the surface of PEI, thereby suppressing surface charge accumulation. It was also shown that the shielding effect of ZnO on high-energy photons during flashover and the catalytic effect of Zn 2+ on PEI molecular chains during hydrothermal treatment had a facilitating and suppressing effect on outgassing, respectively, and consequently affected the flashover. Excitingly, the synergistic effects of both accelerated charge dissipation and suppressed outgassing helped to improve the flashover voltage of PEI by up to 36.7%. The strategy selected here is efficient, scalable, and facile, and the coating is durable, which makes sense for commercial promotion.

The first step in preservative measures for artworks in airtight showcases is the exclusion of outgassing from construction materials or, at least, limitation of the emissions to a minimum acceptable level if the volatile organic compounds (VOCs) generated may be qualified as harmless. Once it is ascertained that the objects in the showcases are responsible for VOC emissions, a step forward becomes necessary, implying showcase ventilation with air flowing through active sorbent materials. Solid phase micro-extraction (SPME) followed by GC separation and MS identification has been applied for checking the outgassing characteristics of different types of materials used for the construction of airtight showcases, and the method was found particularly attractive in terms of speed and sensitivity, suitable for measurements in presence of low-emitting materials. Sampling could also be done in the case interiors, thus making possible detection and recognition of emissions from art objects within a case. A comprehensive preventive conservation scheme has been further devised by means of active air circulation within the showcase and functional sorbent materials along the flow, for complete suppression of gaseous compounds. Control of the compounds in the air flow and of their filtration efficacy was achieved by direct sampling, also using SPME fibers. Continuous monitoring of the air quality in the showcases has been developed with insertion of a photoionization detector capable of detecting the VOCs in the air by inducing molecular ionization, and measuring the generated photocurrent. The system is not selective, but gives the total concentration, reaching ppb sensitivity with high-quality data. In addition it includes temperature and humidity sensors, making the whole a useful instrument for environment control. [ABSTRACT FROM AUTHOR]

Rivers connect the land and the oceans, acting as both active pipes and containers transporting carbon and other substances from terrestrial ecosystems to aquatic ecosystems. Meanwhile, rivers can release huge amounts of CO2 to the atmosphere. However, estimates of global riverine CO2 emissions remain greatly uncertain owing to the absence of a comprehensive spatially and temporally CO2 emissions measurement, especially in river source regions. In this study, riverine partial pressure of CO2 (pCO2) and CO2 efflux (FCO2) in the Yellow River source region under different landcover types, including glaciers, permafrost, wetlands, and grasslands, were investigated in April, June, August, and October 2016. The relevant chemical parameters and environmental parameters, including pH, dissolved oxygen (DO), and dissolved organic carbon (DOC), were analyzed to explore the main control factors of riverine pCO2 and FCO2. The results showed that the rivers in the Yellow River source region were a net CO2 source, with the pCO2 ranging from 181 to 2441 μatm and the FCO2 from -221 to 6892 g C m-2 yr-1. Both the pCO2 and FCO2 showed strong spatial and temporal variations. The average FCO2 in August was higher than that in other months, with the lowest in October. In alpine climates, low temperature conditions played a crucial role in limiting biological activity and reducing CO2 emissions. The lowest FCO2 values (-221 g C m-2 yr-1) were observed in the glacier and permafrost regions. By integrating seasonal changes of water surface area, the total CO2 efflux was estimated at 0.37 ± 0.49 Tg C yr-1, which is significantly higher than previous studies. Although it is still a small proportion of CO2 emissions compared with the whole Yellow River Basin, but there is a huge carbon emissions potential. Since the permafrost in the source region of the Yellow River is rich in large amounts of ice and organic carbon, the continuously increasing temperature due to global warming will accelerate not only the mobilization of organic carbon in permafrost, but also the degradation of organic carbon by soil microorganisms. As a consequence, huge amounts of CO2 release from soils and rivers is anticipated. [ABSTRACT FROM AUTHOR]

Aims. We explore volcanic CO2-outgassing on purely rocky, stagnant-lid exoplanets of different interior structures, compositions, thermal states, and age. We focus on planets in the mass range of 1–8 M⊕ (Earth masses). We derive scaling laws to quantify first- and second-order influences of these parameters on volcanic outgassing after 4.5 Gyr of evolution. Methods. Given commonly observed astrophysical data of super-Earths, we identify a range of possible interior structures and compositions by employing Bayesian inference modeling. The astrophysical data comprise mass, radius, and bulk compositional constraints; ratios of refractory element abundances are assumed to be similar to stellar ratios. The identified interiors are subsequently used as input for two-dimensional (2D) convection models to study partial melting, depletion, and outgassing rates of CO2. Results. In total, we model depletion and outgassing for an extensive set of more than 2300 different super-Earth cases. We find that there is a mass range for which outgassing is most efficient (~2–3 M⊕, depending on thermal state) and an upper mass where outgassing becomes very inefficient (~5–7 M⊕, depending on thermal state). At small masses (below 2–3 M⊕) outgassing positively correlates with planet mass, since it is controlled by mantle volume. At higher masses (above 2–3 M⊕), outgassing decreases with planet mass, which is due to the increasing pressure gradient that limits melting to shallower depths. In summary, depletion and outgassing are mainly influenced by planet mass and thermal state. Interior structure and composition only moderately affect outgassing rates. The majority of outgassing occurs before 4.5 Gyr, especially for planets below 3 M⊕. Conclusions. We conclude that for stagnant-lid planets, (1) compositional and structural properties have secondary influence on outgassing compared to planet mass and thermal state, and (2) confirm that there is a mass range for which outgassing is most efficient and an upper mass limit, above which no significant outgassing can occur. Our predicted trend of CO2-atmospheric masses can be observationally tested for exoplanets. These findings and our provided scaling laws are an important step in order to provide interpretative means for upcoming missions such as JWST and E-ELT, that aim at characterizing exoplanet atmospheres. [ABSTRACT FROM AUTHOR]

CO2 outgassing from rivers is a critical component for evaluating riverine carbon cycle, but it is poorly quantified largely due to limited measurements and modeling of gas transfer velocity (k) in subtropical streams and rivers. We measured CO2 flux rates, k and partial pressure (pCO2) in river networks of the Three Gorges Reservoir (TGR) region, a typical area in the upper Yangtze River with monsoonal climate and mountainous terrain. The observed k values (k600 = 48.4 ± 53.2 cm/h) were showed large variability due to spatial variations in physical controls on surface water turbulence. Our k measurements using chambers were comparable with model derived velocities. Unlike in open waters, k is more pertinent to flow velocity and water depth in the studied small rivers. Our results show that TGR river networks emitted approx. 1.4 Tg CO2/y using varying approaches such as chambers, measured k and developed k model. This study suggests that incorporating scale-appropriate k measurements into extensive pCO2 investigation is required to refine basin-wide carbon budgets in the subtropical streams and small rivers. We concluded that simple parameterization of k as a function of morphological characteristics was site specific and hence highly variable. k models should be developed for stream studies to evaluate the contribution of these regions to atmospheric CO2. [ABSTRACT FROM AUTHOR]

A 2D simulation based on particle-in-cell and Monte Carlo collision algorithm is implemented to investigate the accumulation and dissipation of surface charges on an insulator during flashover with outgassing in vacuum. A layer of positive charges is formed on the insulator after the secondary electrons emission (SEE) reaches saturation. With the build-up of local pressure resulting from gas desorption, the incident energy of electrons is affected by electron-neutral collisions and field distortion, remarkably decreasing the charge density on the insulator. Gas desorption ionization initiates near the anode, culminating, and then abates, followed by a steady and gradual augmentation as the negatively charged surface spreads towards the cathode and halts the SEE nearby. The initiation of flashover development is discussed in detail, and a subdivision of flashover development is proposed, including an anode-initiated desorption ionization avalanche, establishment of a plasma sheath, and plasma expansion. The transform from saturation to explosion of space charges and dissipation of the surface charge are revealed, which can be explained by the competition between multipactor electrons and ionized electrons. [ABSTRACT FROM AUTHOR]

The delivery of dissolved carbon from rivers to coastal oceans is an important component of the global carbon budget. From November 2013 to December 2014, we investigated freshwater-saltwater mixing effects on dissolved carbon concentrations and CO2 outgassing at six locations along an 88-km-long estuarine river entering the Northern Gulf of Mexico with salinity increasing from 0.02 at site 1 to 29.50 at site 6 near the river’s mouth. We found that throughout the sampling period, all six sites exhibited CO2 supersaturation with respect to the atmospheric CO2 pressure during most of the sampling trips. The average CO2 outgassing fluxes at site 1 through site 6 were 162, 177, 165, 218, 126, and 15 mol m−2 year−1, respectively, with a mean of 140 mol m−2 year−1 for the entire river reach. In the short freshwater river reach before a saltwater barrier, 0.079 × 108 kg carbon was emitted to the atmosphere during the study year. In the freshwater-saltwater mixing zone with wide channels and river lakes, however, a much larger amount of carbon (3.04 × 108 kg) was emitted to the atmosphere during the same period. For the entire study period, the river’s freshwater discharged 0.25 × 109 mol dissolved inorganic carbon (DIC) and 1.77 × 109 mol dissolved organic carbon (DOC) into the mixing zone. DIC concentration increased six times from freshwater (0.24 mM) to saltwater (1.64 mM), while DOC showed an opposing trend, but to a lesser degree (from 1.13 to 0.56 mM). These findings suggest strong effects of freshwater-saltwater mixing on dissolved carbon dynamics, which should be taken into account in carbon processing and budgeting in the world’s estuarine systems. [ABSTRACT FROM AUTHOR]

Off-gassed compounds emitted from various materials can, in some instances, present health risks. In order to assess the potential health risks, off-gassed compounds must be identified, quantified, and evaluated relative to known health-based exposure guidance levels. We present a simple screening method for doing this that combines thermogravimetric analysis with thermal desorption-gas chromatography-mass spectrometry. The masses of particular volatile compounds are estimated over the course of a short-term, acute exposure. Assumptions (or measurements) of a room size can be used to convert these mass estimates to estimated concentrations, which can then be compared with readily available health-based exposure thresholds. [ABSTRACT FROM AUTHOR]

The conflicting operation objectives between rapid load following and the fuel depletion avoidance as well as the strong interactions between the thermal and electrical parameters make the SOFC system difficult to control. This study focuses on the design of the decoupling control for the thermal and electrical characteristics of the SOFC system through anode offgas recycling (AOR). The decoupling control system can independently manipulate the thermal and electrical parameters, which interact with one another in most cases, such as stack temperatures, burner temperature, system current, and system power. Under the decoupling control scheme, the AOR is taken as a manipulation variable. The burner controller maintains the burner temperature without being affected by abrupt power change. The stack temperature controller properly coordinates with the burner temperature controller to independently modulate the stack thermal parameters. For the electrical problems, the decoupling control scheme shows its superiority over the conventional controller in alleviating rapid load following and fuel depletion avoidance. System-level simulation under a power-changing case is performed to validate the control freedom between the thermal and electrical characteristics as well as the stability, efficiency, and robustness of the novel system control scheme. [ABSTRACT FROM AUTHOR]

Abstract: To maintain the chance of keeping the average global temperature increase below 2°C and to limit long‐term climate change, removing carbon dioxide from the atmosphere (carbon dioxide removal, CDR) is becoming increasingly necessary. We analyze optimal and cost‐effective climate policies in the dynamic integrated assessment model (IAM) of climate and the economy (DICE2016R) and investigate (1) the utilization of (ocean) CDR under different climate objectives, (2) the sensitivity of policies with respect to carbon cycle feedbacks, and (3) how well carbon cycle feedbacks are captured in the carbon cycle models used in state‐of‐the‐art IAMs. Overall, the carbon cycle model in DICE2016R shows clear improvements compared to its predecessor, DICE2013R, capturing much better long‐term dynamics and also oceanic carbon outgassing due to excess oceanic storage of carbon from CDR. However, this comes at the cost of a (too) tight short‐term remaining emission budget, limiting the model suitability to analyze low‐emission scenarios accurately. With DICE2016R, the compliance with the 2°C goal is no longer feasible without negative emissions via CDR. Overall, the optimal amount of CDR has to take into account (1) the emission substitution effect and (2) compensation for carbon cycle feedbacks. [ABSTRACT FROM AUTHOR]

The feasibility of utilizing commercially available silica aerogel-based flexible composite blankets as passive thermal control element in applications such as extraterrestrial environments is investigated. Differential scanning calorimetry showed that aerogel blanket was thermally stable over - 150 to 126 °C. The outgassing behavior, e.g., total mass loss, collected volatile condensable materials, water vapor regained and recovered mass loss, was within acceptable range recommended for the space applications. ASTM tension and tear tests confirmed the material’s mechanical integrity. The thermo-optical properties remained nearly unaltered in simulated space environmental tests such as relative humidity, thermal cycling and thermo-vacuum tests and confirmed the space worthiness of the aerogel. Aluminized Kapton stitched or anchored to the blanket could be used to control the optical transparency of the aerogel. These outcomes highlight the potential of commercial aerogel composite blankets as passive thermal control element in spacecraft. Structural and chemical characterization of the material was also done using scanning electron microscopy, Fourier transform infrared spectroscopy and x-ray photoelectron spectroscopy. [ABSTRACT FROM AUTHOR]

Previous studies have shown that molecular contamination outgassed from nonmetallic materials tends toward deposition on optical surfaces as droplets instead of nearly uniform thin films. Failure to consider the sources and effects of these droplets in an optical instrument omits large throughput losses due to scattering. This paper demonstrates that a simple treatment of optical system surfaces using vacuum ultraviolet (VUV) radiation reduces the formation of molecular contaminant droplets. VUV radiation exposure of a nominally clean silicon surface using a deuterium lamp suffices to remove hydrocarbon and carbonyl species that allow wetting of the surface by the contaminant. The throughput losses of the contamination due to droplet scattering can be reduced significantly. [ABSTRACT FROM AUTHOR]

Radiation is an important means of heat transfer inside an electric arc furnace (EAF). To gain insight into the complex processes of heat transfer inside the EAF vessel, not only radiation from the surfaces but also emission and absorption of the gas phase and the dust cloud need to be considered. Furthermore, the radiative heat exchange depends on the geometrical configuration which is continuously changing throughout the process. The present paper introduces a system model of the EAF which takes into account the radiative heat transfer between the surfaces and the participating medium. This is attained by the development of a simplified geometrical model, the use of a weighted-sum-of-gray-gases model, and a simplified consideration of dust radiation. The simulation results were compared with the data of real EAF plants available in literature. [ABSTRACT FROM AUTHOR]

Kinetics of the formation of residual atmosphere in vacuum devices with internal adhesive joints and the application of the mass spectral and chromatographic methods to measure the specific outgassing rate of volatile compounds from the cured adhesives are considered in this paper. The outgassing comparison data for the various types of adhesives are given and the effectiveness of the outgassing of adhesive joints is demonstrated. The possible options to provide vacuum in the various devices are considered. At moderate requirements to the residual pressure (about 10-2 Pa), it is enough to degass the adhesive joints during a few hours. It is much more difficutt to provide vacuum in devices with internal adhesive joints at the level of about 10-4 Pa This requires the use of the built-in getter and the high temperature degassing. It is expedient to provide deep vacuum (10-5 -10-4 Pa) in the rare-used or once-used devices by short (a few minutes) activation the built-in getters before operating the vacuum devices. This allows to remove the main residual gas hydrocarbons component from the vacuum house and provide the necessary level of vacuum for a certain interval of time. [ABSTRACT FROM AUTHOR]

Abstract: Plinian lapilli from the 1060 Common Era Glass Mountain rhyolitic eruption of Medicine Lake Volcano, California, were collected and analyzed for vesicularity and permeability. A subset of the samples were deformed at a temperature of 975°, under shear and normal stress, and postdeformation porosities and permeabilities were measured. Almost all undeformed samples fall within a narrow range of vesicularity (0.7–0.9), encompassing permeabilities between approximately 10−15 m2 and 10−10 m2. A percolation threshold of approximately 0.7 is required to fit the data by a power law, whereas a percolation threshold of approximately 0.5 is estimated by fitting connected and total vesicularity using percolation modeling. The Glass Mountain samples completely overlap with a range of explosively erupted silicic samples, and it remains unclear whether the erupting magmas became permeable at porosities of approximately 0.7 or at lower values. Sample deformation resulted in compaction and vesicle connectivity either increased or decreased. At small strains permeability of some samples increased, but at higher strains permeability decreased. Samples remain permeable down to vesicularities of less than 0.2, consistent with a potential hysteresis in permeability‐porosity between expansion (vesiculation) and compaction (outgassing). We attribute this to retention of vesicle interconnectivity, albeit at reduced vesicle size, as well as bubble coalescence during shear deformation. We provide an equation that approximates the change in permeability during compaction. Based on a comparison with data from effusively erupted silicic samples, we propose that this equation can be used to model the change in permeability during compaction of effusively erupting magmas. [ABSTRACT FROM AUTHOR]

The storage of natural gas in salt caverns can entail the risk of H 2 S generation, which in turn leads to gas pollution. H 2 S is generated by bacterial sulfate reduction. The bacteria use aqueous sulfate (aq) as an electron acceptor to oxidize the dissolved hydrocarbons and generate sulfide. Anhydrite is available in the rock salt surrounding the cavern and acts as a sulfate (aq) source. The stored natural gas, with its main component, methane, is in solubility equilibrium with the brine and is additionally delivered by diffusion into the brine. The generated H 2 S reaches the stored gas by outgassing from the brine. In this study, these processes are simulated by one- and three-dimensional hydrogeochemical diffusive mass transport models, which are based on equilibrium reactions for gas-water-rock interactions and kinetic reactions for sulfate reduction. Modelling results show that the greatest amount of H 2 S is generated in the brine. The amount of generated H 2 S (g) is mainly controlled by the amount of available sulfate (aq) as well as the rate of diffusion, which is coupled with the maximum operating live time of salt caverns. Additionally, the amount of generated and released H 2 S (g) is sensitive to the chosen kinetic rate constant. To ensure constant gas quality over time, the gas and the brine must be analyzed continuously and technical methods must be applied when the H 2 S (g) concentration increases. According to the modelling results, H 2 S (g) generation is inhibited by addition of dissolved ferrous iron to the brine. Dissolved ferrous iron reacts with sulfide-sulfur to form mackinawite (FeS (s) ) so that aqueous sulfide is no longer available for H 2 S (g) generation. Another method is the addition of NaOH to increase the pH of the brine. Then, higher fractions of generated sulfide-sulfur are transformed to free S 2− (aq) instead of H 2 S (g) and H 2 S (aq) . [ABSTRACT FROM AUTHOR]

High-power laser facilities, such as Laser MegaJoule, are currently being operated for inertial confinement fusion experiments. Emission of volatile organic compounds (VOC) and moreover semivolatile organic compounds (SVOCs) from seals in laser environment is of tremendous importance for the optics lifetime and laser performance. That is why all the seals were screening in the same conditions: 48 h at 30°C and three successive cycle of 1.5 h at 50°C. This paper focuses on the qualification test performed on three seals: two ethylene propylene diene monomer (EPDM) and one fluoropolymer (FPM). It is shown that the molded and the extruded EPDM do not outgas the same amount neither the same molecules whereas EPDM and FPM outgas nearly the same level of phthalates. [ABSTRACT FROM AUTHOR]

Oxide dispersion-strengthened ferritic stainless steels are foreseen as fuel cladding tube materials for the new generation of sodium fast nuclear reactors. Those materials, which exhibit remarkable creep properties at high temperature, are reinforced by a dense precipitation of nanometric oxides. This precipitation is obtained by mechanical alloying of a powder and subsequent consolidation. Before consolidation, to obtain a fully dense material, the powder is vacuumed to outgas trapped gases and species adsorbed at the surface of the powder particles. This operation is commonly done at moderate to high temperature to evacuate as much as possible volatile species. This paper focuses on the influence of outgassing conditions on some properties of the further consolidated materials. Chemical composition and microstructural characterization of different materials obtained from various outgassing cycles are compared. Finally, impact toughness of those materials is evaluated by using Charpy testing. This study shows a significant influence of the outgassing conditions on the mechanical properties of the consolidated material. However, microstructure and oxygen contents seem poorly impacted by the various outgassing conditions. [ABSTRACT FROM AUTHOR]

The 2014-2015 Holuhraun eruption was the largest fissure eruption in Iceland in the last 200 years. This flood basalt eruption produced ~ 1.6 km of lava, forming a lava flow field covering an area of ~ 84 km. Over the 6-month course of the eruption, ~ 11 Mt of SO were released from the eruptive vents as well as from the cooling lava flow field. This work examines the post-eruption SO flux emitted by the Holuhraun lava flow field, providing the first study of the extent and relative importance of the outgassing of a lava flow field after emplacement. We use data from a scanning differential optical absorption spectroscopy (DOAS) instrument installed at the eruption site to monitor the flux of SO. In this study, we propose a new method to estimate the SO emissions from the lava flow field, based on the characteristic shape of the scanned column density distribution of a homogenous source close to the ground. Post-eruption outgassing of the lava flow field continued for at least 3 months after the end of the eruption, with SO flux between < 1 and 9 kg/s. The lava flow field post-eruption emissions were not a significant contributor to the total SO released during the eruption; however, the lava flow field was still an important polluter and caused high concentrations of SO at ground level after lava effusion ceased. [ABSTRACT FROM AUTHOR]

The permeability of magmas to percolating fluids plays a role in controlling eruption explosivity. While measurements of volcanic rock permeability abound, comparison of these values with models that relate hydraulic properties to random heterogeneous pore structures are few. Here, we present such a comparison. First, we generate numerical materials composed of randomly placed spherical objects in a periodic control volume using two dominant pore structure families: (1) where the space between the spherical objects represents the pore phase that can transmit fluid, and (2) where the spherical objects themselves are the pore phase that can transmit fluid. In the former case, we envisage the system to be analogous to initially granular magmas that undergo welding events that serve to progressively reduce the porosity. In the latter case, we envisage the system to be analogous to vesiculating magmas that evolve to high porosities. In both cases, we constrain relationships for fundamental structural parameters for every porosity including the specific surface area and the percolation thresholds and we compare these with theoretical relationships. Importantly, we run lattice Boltzmann method simulations of fluid flow through these systems at a wide range of porosities to constrain the steady state Darcian fluid permeability using the LBflow code. We finally compare these permeability values with (1) other published simulations, (2) published permeability data for natural volcanic rocks or experimental analogues thereof, and (3) theoretical constraints derived from first principles. In all cases, we obtain a good agreement between our idealized numerical random systems and the natural data, as well as results of other theoretical and experimental approaches. We propose that the simple models that we derive and validate can be of wide utility in building more complex models for the evolution of magmas during shallow ascent with broad implications for outgassing efficiency and the development of pore overpressure immediately prior to eruption. [ABSTRACT FROM AUTHOR]

Historically, much attention has been given to the unit processes and the integration of those unit processes to improve product yield. Less attention has been given to the wafer mini environment, either during processing or post processing. This paper contains a detailed discussion on how particles and airborne molecular contaminants (AMCs) from the wafer mini environment interact and produce undesired effects on the wafer which in turn cause devices to fail. Sources of wafer environmental contamination are the processes themselves, ambient environment, outgassing from wafers, and front open unified pod (FOUP) contamination. Establishing a strategy that reduces contamination inside the FOUP mini environment will decrease defect variability and thus increase yield. In manufacturing ecosystem, changing the FOUP or moving the wafers faster or purging with nitrogen to reduce the impact from mini environment is not always an option. Alternative to having a stop gap, it is desired to understand the AMCs and thus exploring sustainable solutions to minimize them below certain thresholds that would cause impact on wafer. NH3-based contamination, extensively discussed in this paper, is observed to cause wafer defects. Thus, explicit knowledge of AMC type is critical, as the most optimized methodology to control various AMCs might not always be the same. Three primary variables that greatly impact this strategy are FOUP contamination mitigation, FOUP material, FOUP metrology, and cleaning method. [ABSTRACT FROM AUTHOR]

During magma ascent, bubbles nucleate, grow, coalesce, and form a variably permeable porous network. The reorganization, failing and sealing of bubble walls may contribute to the opening and closing of the volcanic system. In this contribution we cause obsidian to nucleate and grow bubbles to high gas volume fraction at atmospheric pressure by heating samples to 950°C for different times and we image the growth through a furnace. Following the experiment, we imaged the internal pore structure of selected samples in 3D and then dissected for analysis of textures and dissolved water content remnant in the glass. We demonstrate that in these high viscosity systems, during foaming and subsequent foam-maturation, bubbles near a free surface resorb via diffusion to produce an impermeable skin of melt around a foam. The skin thickens non-linearly through time. The water concentrations at the outer and inner skin margins reflect the solubility of water in the melt at the partial pressure of water in atmospheric and water-rich bubble conditions, respectively. In this regime, mass transfer of water out of the system is diffusion limited and the sample shrinks slowly. In a second set of experiments in which we polished off the skin of the foamed samples and placed them back in the furnace to allow open system outgassing, we observe rapid sample contraction and collapse of the connected pore network under surface tension as the system efficiently outgasses. In this regime, mass transfer of water is permeability limited. We conclude that diffusion-driven skin formation can efficiently seal connectivity in foams. When rupture of melt film around gas bubbles (i.e., skin removal) occurs, then rapid outgassing and consequent foam collapse modulate gas pressurization in the vesiculated magma. The mechanisms described here are relevant to the evolution of pore network heterogeneity in permeable magmas.

A large fraction of the organic carbon derived from land that is transported through inland waters is decomposed along river systems and emitted to the atmosphere as carbon dioxide (CO2). The Amazon River outgasses nearly as much CO2 as the rainforest sequesters on an annual basis, representing ~25% of global CO2 emissions from inland waters. However, current estimates of CO2 outgassing from the Amazon basin are based on a conservative upscaling of measurements made in the central Amazon, meaning both basin and global scale budgets are likely underestimated. The lower Amazon River, from Óbidos to the river mouth, represents ~13% of the total drainage basin area, and is not included in current basin-scale estimates. Here, we assessed the concentration and evasion rate of CO2 along the lower Amazon River corridor and its major tributaries, the Tapajós and Xingu Rivers. Evasive CO2 fluxes were directly measured using floating chambers and gas transfer coefficients (k600) were calculated for different hydrological seasons. Temporal variations in pCO2 and CO2 emissions were similar to previous observations throughout the Amazon (e.g., peak concentrations at high water) and CO2 outgassing was lower in the clearwater tributaries compared to the mainstem. However, k600-values were higher than previously reported upstream likely due to the generally windier conditions, turbulence caused by tidal forces, and an amplification of these factors in the wider channels with a longer fetch. We estimate that the lower Amazon River mainstem emits 20 Tg C year−1 within our study boundaries, or as much as 48 Tg C year−1 if the entire spatial extent to the geographical mouth is considered. Emissions from the Xingu and Tapajós lower tributaries contribute an additional 2.3 Tg C year−1. Including these values with updated basin scale estimates and estimates of CO2 outgassing from small streams we estimate that the Amazon running waters outgasses as much as 0.95 Pg C year−1, increasing the global emissions from inland waters by 15% for a total of 2.45 Pg C year−1. These results highlight the lower reaches of large rivers as a missing gap in basin-scale and global carbon budgets. In the case of the Amazon River, the previously unstudied tidally-influenced reaches contribute to 5% of CO2 emissions from the entire basin.

Under the context of climate change, studying CO2 emissions in alpine rivers is important because of the large carbon storage in these terrestrial ecosystems. In this study, riverine partial pressure of CO2 (pCO2) and CO2 emission flux (FCO2) in the Yellow River source region (YRSR) under different landcover types, including glaciers, permafrost, peatlands, and grasslands, were systematically investigated in April, June, August, and October 2016. Relevant chemical and environmental parameters were analyzed to explore the primary controlling factors. The results showed that most of the rivers in the YRSR were net CO2 source, with the pCO2 ranging from 181 to 2441 μatm and the FCO2 ranging from −50 to 1574 mmol m−2 d−1. Both pCO2 and FCO2 showed strong spatial and temporal variations. The highest average FCO2 was observed in August, while the lowest average was observed in June. Spatially, the lowest FCO2 were observed in the permafrost regions while the highest FCO2 were observed in peatland. By integrating seasonal changes of the water surface area, total CO2 efflux was estimated to be 0.30 Tg C year−1. This indicates that the YRSR was a net carbon source for the atmosphere, which contradicts previous studies that conclude the YRSR as a carbon sink. More frequent measurements of CO2 fluxes, particularly through several diel cycles, are necessary to confirm this conclusion. Furthermore, our study suggested that the riverine dissolved organic carbon (DOC) in permafrost (5.0 ± 2.4 mg L−1) is possibly derived from old carbon released from permafrost melting, which is equivalent to that in peatland regions (5.1 ± 3.7 mg L−1). The degradation of DOC may have played an important role in supporting riverine CO2, especially in permafrost and glacier-covered regions. The percent coverage of corresponding land cover types is a good indicator for estimating riverine pCO2 in the YRSR. In view of the extensive distribution of alpine rivers in the world and their sensitivity to climate change, future studies on dynamics of stream water pCO2 and CO2 outgassing are strongly needed to better understand the global carbon cycle.