Water Inventory Research Articles

Understanding the Impact of Gas Diffusion Layer Degradation on Water Inventory in Low Temperature PEM Fuel Cells for Heavy Duty Vehicles Application: Operando X-Ray and Neutron Imaging Study

Samples from two materials representing the condition at begin and end of life, were selected from testing of commercial, state-of-the-art PEM fuel cell stacks. Using small-area single cell setups specifically developed for visualization purposes, operando synchrotron and neutron imaging experiments to visualize water dynamics and distribution within these cells were performed. In this study, the effects of aging on water inventory in the gas diffusion layers throughout the lifespan of the cells are investigated. The findings provide insights into how aging influences water management, which is crucial for optimizing the performance and longevity of PEM fuel cells for heavy-duty applications.

Understanding the Impact of Gas Diffusion Layer Degradation on Water Inventory in Low Temperature PEM Fuel Cells for Heavy Duty Vehicles Application: Operando X-Ray and Neutron Imaging Study

Samples from two materials representing the condition at begin and end of life, were selected from testing of commercial, state-of-the-art PEM fuel cell stacks. Using small-area single cell setups specifically developed for visualization purposes, operando synchrotron and neutron imaging experiments to visualize water dynamics and distribution within these cells were performed. In this study, the effects of aging on water inventory in the gas diffusion layers throughout the lifespan of the cells are investigated. The findings provide insights into how aging influences water management, which is crucial for optimizing the performance and longevity of PEM fuel cells for heavy-duty applications.

The erosion of large primary atmospheres typically leaves behind substantial secondary atmospheres on temperate rocky planets

Exoplanet exploration has revealed that many—perhaps most—terrestrial exoplanets formed with substantial H2-rich envelopes, seemingly in contrast to solar system terrestrials, for which there is scant evidence of long-lived primary atmospheres. It is not known how a long-lived primary atmosphere might affect the subsequent habitability prospects of terrestrial exoplanets. Here, we present a new, self-consistent evolutionary model of the transition from primary to secondary atmospheres. The model incorporates all Fe-C-O-H-bearing species and simulates magma ocean solidification, radiative-convective climate, thermal escape, and mantle redox evolution. For our illustrative example TRAPPIST-1, our model strongly favors atmosphere retention for the habitable zone planet TRAPPIST-1e. In contrast, the same model predicts a comparatively thin atmosphere for the Venus-analog TRAPPIST-1b, which would be vulnerable to complete erosion via non-thermal escape and is consistent with JWST observations. More broadly, we conclude that the erosion of primary atmospheres typically does not preclude surface habitability, and frequently results in large surface water inventories due to the reduction of FeO by H2.

Water Evolution and Inventories of Super-Earths Orbiting Late M Dwarfs

Super-Earths orbiting M dwarf stars may be the most common habitable planets in the Universe. However, their habitability is threatened by intense irradiation from their host stars, which drives the escape of water to space and can lead to surface desiccation. We present simulation results of a box model incorporating deep-water cycling between interior and atmosphere and water loss to space for terrestrial planets of mass 1–8 M ⊕ orbiting in the habitable zone of a late M dwarf. Energy-limited loss decreases with planetary mass, while diffusion-limited loss increases with mass. Depending on where it orbits in the habitable zone, a 1 M ⊕ planet that starts with 3–8 Earth Oceans can end up with an Earthlike surface of oceans and exposed continents; for an 8 M ⊕ super-Earth, that range is 3–12 Earth Oceans. Planets initialized with more water end up as waterworlds with no exposed continents, while planets that start with less water have desiccated surfaces by 5 Gyr. Since the mantles of terrestrial planets can hold much more water than is currently present in Earth’s atmosphere, none of our simulations result in Dune planets—such planets may be less common than previously thought. Further, more water becomes sequestered within the mantle for larger planets. A super-Earth at the inner edge of the habitable zone tends to end up as either a waterworld or with a desiccated surface; only a narrow range of initial water inventory yields an Earthlike surface.

Quantitative evaluation of uncertain parameters for thermal-hydraulic experiments based on the COSINE code

Identifying important phenomena and parameters of LBLOCAs is an important step in nuclear power safety evaluation. Traditional identification processes are based on experience and incorporate important phenomena and parameters without quantifying specific aspects of the models. To accurately identify physical effects, this paper presents the use of multiphase field subchannel code for simulation analysis as applied to numerical examples and specific reactor thermal-hydraulic problems. The results indicate that the code can simulate the relevant phenomena, and the calculation band of the refill stage is narrow, while the calculation band of the reflood stage is wide. In addition, the key impact models are captured. The radiation model most significantly impacts the cladding temperature in the core, and the heat transfer model of transition boiling to the gas phase is most strongly influenced by the quenching time. The interfacial heat transfer model of the large bubble regime for the liquid plays a major role in influencing the water inventory of the lower plenum in the downcomer.

Carbon footprint and water inventory of the production of lithium in the Atacama Salt Flat, Chile

The objective of this work is to estimate the carbon footprint and water footprint inventory using primary information of the lithium carbonate and lithium hydroxide production of SQM and Albemarle in the Atacama Salt Flat, which represented 30 % of global lithium production in 2020. A contribution of the work is demonstrating that these two operations have the lowest reported GHG global emissions per unit production of lithium carbonate and of lithium hydroxide, and that this is possible due to natural and anthropogenic characteristics. Another contribution is that the natural advantages of the Atacama deposit should remain crucial in this leadership in spite of the introduction of an assortment of technologies in the reduction of GHG emissions in the future. A third contribution is showing that the largest cause of the carbon footprint for lithium carbonate production at the Atacama Salt Flat was soda ash, with 63.1 % of the total.

Meteoric water and glacial melt in the southeastern Amundsen Sea: a time series from 1994 to 2020

Abstract. Ice sheet mass loss from Antarctica is greatest in the Amundsen Sea sector, where “warm” modified Circumpolar Deep Water moves onto the continental shelf and melts and thins the bases of ice shelves hundreds of meters below the sea surface. We use nearly 1000 paired salinity and oxygen isotope analyses of seawater samples collected on seven expeditions from 1994 to 2020 to produce a time series of glacial meltwater inventory for the southeastern Amundsen Sea continental shelf. Deep water column salinity–δ18O relationships yield freshwater end-member δ18O values from -31.3±1.0‰ to -28.4±1.0‰, consistent with the isotopic composition of local glacial ice. We use a two-component meteoric water end-member approach that accounts for precipitation in the upper water column, and a pure glacial meteoric water end-member is employed for the deep water column. Meteoric water inventories are comprised of nearly pure glacial meltwater in deep shelf waters and of >74 % glacial meltwater in the upper water column. Total meteoric water inventories range from 8.1±0.7 to 9.6±0.8 m and exhibit greater interannual variability than trend over the study period, based on the available data. The relatively long residence time in the southeastern Amundsen Sea allows changes in mean meteoric water inventories to diagnose large changes in local melt rates, and improved understanding of regional circulation could produce well-constrained glacial meltwater fluxes. The two-component meteoric end-member technique improves the accuracy of the sea ice melt and meteoric fractions estimated from seawater δ18O measurements throughout the entire water column and increases the utility for the broader application of these estimates.

Life cycle assessment of wastewater reuse alternatives in urban water system

Increasing water stress necessitates adopting wastewater reuse for sustainable living in urban environment. Trade-offs exist between different wastewater reuse applications and their environmental impacts. The impacts associated with developing urban water systems (UWSs) are not known, and city scale wastewater reuse in general is not well understood. This study investigates indirect, direct, non-potable and hybrid wastewater reuse scenarios in a real UWS to suggest environmentally sustainable reuse strategy using life cycle approach. The study develops a comprehensive life cycle inventory of actual water and wastewater utilities. Results show that all environmental impacts except eutrophication increases for direct potable and hybrid reuse. The centralized non-potable reuse (NPR) had lowest impact scores related with ecotoxicities while impacts including global warming were equivalent to the baseline. The study recommends adopting centralized NPR in developing UWSs while highlighting the treatment processes and impacts for reuse scenarios favorable in high to extreme water stressed regions.

Research and Application of Intelligent Water Source Well Air Defense Pumping and Dry Burning Technology

The surface water injection technology for developing low permeability reservoirs comes from the water supply of water source wells. The groundwater resources in oil fields are limited, with high water consumption and a decrease in water level, lacking effective monitoring methods. In recent years, there have been frequent occurrences of unsafe waste of electrical energy due to dry burning during pumping in water source wells, which has seriously affected the normal water injection of oilfield formations. In order to prevent dry burning of water source wells by pumping air, research on intelligent air defense dry burning technology for water source wells has been carried out. The automatic pump stop alarm at low water level and the automatic pump start at high water level avoid the phenomenon of dry burning during pumping in the water source well, ensure the normal operation of the water source well, and ensure sufficient water injection from the source. Reduce employee labor intensity and achieve the goal of optimizing human resources. Associate the start and stop status of the water source well with the tank position of the water injection station to achieve automatic water distribution and inventory, achieve digital management and fine management, and achieve the goal of reducing costs and increasing efficiency, which has promotion value.

The Runaway Greenhouse Effect on Hycean Worlds

Hycean worlds are a proposed subset of sub-Neptune exoplanets with substantial water inventories, liquid surface oceans, and extended hydrogen-dominated atmospheres favorable for habitability. We aim to quantitatively define the inner edge of the Hycean habitable zone (HZ) using a 1D radiative-convective model. As a limiting case, we model a dry hydrogen–helium envelope above a surface ocean. For a 1 bar (10,100 bar) atmosphere, the hydrogen greenhouse effect alone sets the inner edge of the HZ at 0.216 au (0.58, 3.71 au) for a Sun-like G star and at 0.0364 au (0.110, 0.774 au) for an 3500 K M star. Introducing water vapor into the atmosphere, the runaway greenhouse instellation limit is greatly reduced due to the presence of superadiabatic layers where convection is inhibited. This moves the inner edge of the HZ from ≈1 au for a G star to 1.6 au (3.85 au) for a Hycean world with a H2–He inventory of 1 bar (10 bar). For an M star, the inner edge is equivalently moved from 0.17–0.28 au (0.54 au). Our results suggest that most of the current Hycean world observational targets are not likely to sustain a liquid water ocean. We present an analytical framework for interpreting our results, finding that the maximum possible outgoing longwave radiation scales approximately inversely with the dry mass inventory of the atmosphere. We discuss the possible limitations of our 1D modeling and recommend the use of 3D convection-resolving models to explore the robustness of superadiabatic layers.

Jupiter’s Early Luminosity May Have Driven off Io’s Initial Water Inventory

After its formation, Jupiter was substantially more luminous than it is at the present day (104 times). Right after formation, the inner satellites Io and Europa would have received an order-of-magnitude larger incoming flux from Jupiter, than solar insolation. However, little work has been done to examine the impact this would have had on the Galilean satellites. In this work we explore the possibility that Jupiter’s early luminosity could have caused the loss of any initial water inventory on Io and Europa. We find that, depending on Jupiter’s luminosity after the proto-Jovian disk dissipates, heating from Jupiter could drive rapid water loss via hydrodynamic escape. If early tidal heating dehydrated Io’s accreted silicates, this may provide a mechanism to lose Io’s initial water inventory.

Super-Earth GJ 667Cc: Age and XUV Irradiances of the Temperate-zone Planet with Potential for Advanced Life

GJ 667Cc is a nearby (23.6 lt-yr) super-Earth that orbits within the habitable zone (HZ) of its ∼M2V host star and has Earth-like properties: (M- R ∼ 1.7 R ⊕; T eq (A = 0.3) ∼ 277 K). The age of the star/planet is poorly constrained at 2 ≳ Gyr. Age is crucial in evaluating the potential for complex life. We determine an age of ∼6.10 ± 2.2 Gyr from our recent Age-Rotation relations. This is compatible with its low metallicity ([Fe/H] ∼ −0.59 ± 0.1 dex), weak coronal/chromospheric X-ray/FUV emissions, and space motions. We also determine the photodissociating/photoionizing X-ray-UV irradiances from Chandra and ROSAT X-ray and HST/FUV observations. Like most HZ-planets hosted by M-dwarfs, these irradiances are much higher than Earth's and are detrimental to the planet's atmosphere retention, water inventories, and habitability. A strong geomagnetic field could mitigate atmospheric erosion, permitting life to develop.

Assessing Transboundary Impacts of Energy-Driven Water Footprint on Scarce Water Resources in China: Catchments under Stress and Mitigation Options.

The energy supply chains operating beyond a region's jurisdiction can exert pressure on the availability of water resources in the local area. In China, however, there is a lack of transboundary assessments that investigate the effects of energy consumption on water stress within and across river basins. In this study, we therefore investigate transboundary impacts on scarce water resources that are induced by energy demands (i.e., electricity, petroleum, coal mining, oil and gas extraction, and gas production). We develop a bottom-up high spatial resolution water inventory and link it to a 2017 multiregional input-output (MRIO) table of China to analyze supply chain scarce water use at provincial and river basin levels. We find that the energy-driven water footprint accounts for 21.6% of national water usage, of which 35.7% is scarce water. Nonelectric power energy sectors contribute to around half of the nation's scarce water transfer. We identify three sets of catchments whose water resources are stressed by energy demand, i.e., (a) from the northern Hai River Basin to the eastern part of the Yellow River Basin and the Huai River Basin, (b) the northern area of the Northwest Rivers, and (c) the developed coastal city clusters in the Yangtze River Basin and the Pearl River Basin. We then evaluate the impacts of eight mitigation options, which may potentially shift around half of the moderate- or high-stress areas in the Hai River Basin and the Northwest Rivers to low to moderate (or even low) stress. We highlight the need for transboundary collaboration to sustain water-constrained energy demand and to develop targeted measures to mitigate stress on water resources within a river basin.

Taking Water Inventories at Coke Plants

Taking Water Inventories at Coke Plants

Freshwater Management Discourses in the Northern Peruvian Andes: The Watershed-Scale Complexity for Integrating Mining, Rural, and Urban Stakeholders.

The Peruvian environmental action plan seeks headwaters protection as one of its integrated watershed management objectives. However, heterogeneous social and environmental conditions shape this freshwater management challenge at subnational scales. We have noticed different interpretations of this challenge. To map the debate, understand the diverse interpretations, and frame political choices, we conducted semi-structured interviews with institutional and non-institutional stakeholders for performing discourse analysis in an Andean watershed where mountaintop gold mining, midstream farmers, and the downstream Cajamarca city coexist. One discourse dominates the debate on protecting the freshwater supply and argues the importance of river impoundment, municipal storage capacity, and institutional leadership. The other two discourses revolve around protecting the mountain aquifer. The second discourse does so with a fatalistic view of headwaters protection and rural support. The third discourse partially shifts the debate towards the need for improving rural capacity building and (ground)water inventories. To understand evolutions in society, it is crucial to understand these three discourses, including the types of knowledge that actors present as legitimate, the attributed roles to all stakeholders, and the kinds of worldviews informing each discourse. The interaction among discourses could hinder integrated watershed management at worst or, at best, help inspire multi-stakeholder collaboration.

The Runaway Greenhouse on Sub-Neptune Waterworlds

The implications of the water vapor runaway greenhouse phenomenon for water-rich sub-Neptunes are developed. In particular, the nature of the postrunaway equilibration process for planets that have an extremely high water inventory is addressed. Crossing the threshold from subrunaway to superrunaway conditions leads to a transition from equilibrated states with cold, deep liquid oceans and deep interior ice-X phases to states with hot supercritical fluid interiors. There is a corresponding marked inflation of radius for a given mass, similar to the runaway greenhouse radius inflation effect noted earlier for terrestrial planets, but in the present case the inflation involves the entire interior of the planet. The calculation employs the AQUA equation-of-state database to simplify the internal structure calculation. Some speculations concerning the effect of H2 admixture, silicate cores, and hot- versus cold-start evolution trajectories are offered. Observational implications are discussed though the search for the mass–radius signature of the phenomena considered is limited by degeneracies and by lack of data.

Mantle mineralogy limits to rocky planet water inventories

ABSTRACT Nominally anhydrous minerals in rocky planet mantles can sequester multiple Earth-oceans’ worth of water. Mantle water storage capacities therefore provide an important constraint on planet water inventories. Here we predict silicate mantle water capacities from the thermodynamically-limited solubility of water in their constituent minerals. We report the variability of upper mantle and bulk mantle water capacities due to (i) host star refractory element abundances that set mantle mineralogy, (ii) realistic mantle temperature scenarios, and (iii) planet mass. We find that transition zone minerals almost unfailingly dominate the water capacity of the mantle for planets of up to ∼1.5 Earth masses, possibly creating a bottleneck to deep water transport, although the transition zone water capacity discontinuity is less pronounced at lower Mg/Si. The pressure of the ringwoodite-perovskite phase boundary defining the lower mantle is roughly constant, so the contribution of the upper mantle reservoir becomes less important for larger planets. If perovskite and postperovskite are relatively dry, then increasingly massive rocky planets would have increasingly smaller fractional interior water capacities. In practice, our results represent initial water concentration profiles in planetary mantles where their primordial magma oceans are water-saturated. This work is a step towards understanding planetary deep water cycling, thermal evolution as mediated by rheology and melting, and the frequency of ocean planets.

A 2.0 GS/s Two-Stage Quad-Channel Digital Downconverter for a 380 GHz Spaceborne Atmospheric HO Monitoring Instrument

This brief presents a quad-channel 2.0 GS/s digital downconverter (DDC) chip in 65nm CMOS that supports the NASA Stratospheric Water Inventory and Tomography by Convective Hydration (SWITCH) spaceborne instrument. The presented DDC chipset provides a wide input bandwidth and allows the transmitted 380 GHz signals to be channelized to perform the atmospheric measurements. The prototype DDC chip is implemented in a 65nm CMOS technology and consumes 177mW of DC power.

Identification of ventilated and submarine glacial meltwaters in the Amundsen Sea, Antarctica, using noble gases

To delineate the glacial meltwater distribution, we used five noble gases for optimum multiparameter analysis (OMPA) of the water masses in the Dotson-Getz Trough (DGT), Amundsen Sea. The increased number of tracers allowed us to define potential source waters at the surface, which have not been possible with a small set of tracers. The highest submarine meltwater (SMW) fraction (~0.6%) was present at the depth of ~450 m near the Dotson Ice Shelf. The SMW appeared to travel beyond the continental shelf break along an isopycnal layer. Air-equilibrated freshwater (up to 1.5%), presumably ventilated SMW (VMW) and surface melts, was present in the surface layer (<100 m). The distribution of SMW indicates that upwelled SMW, known as an important carrier of iron to the upper layer, amounts for 29% of the SMW in the DGT. The clear separation of VMW from SMW enabled partitioning of meltwater into locally-produced and upstream fractions and estimation of the basal melting of 53 – 94 Gt yr-1 for the adjacent ice shelves, assuming that the SMW fractions represent accumulation since the previous Winter Water formation. The Meteoric Water (MET) fractions, consisting of SMW and VMW, comprised 24% of those derived from oxygen isotopes, indicating that the annual input from basal melting is far less than the inventory of meteoric water, represented by MET.

Towards harmonised and regionalised life cycle assessment of fruits: A review on citrus fruit

The citrus fruit sector is globally relevant. Considering the great contribution of agri-food systems to environmental impacts, assessing and reducing them can make a positive contribution to the environment. Life Cycle Assessment (LCA) is a widespread tool used to quantify the complex environmental interactions of agri-food systems in general and perennial fruit crops in particular. However, methodological aspects need to be harmonised to perform useful and representative LCAs on fruits. The goal of this study is to provide an updated descriptive and critical review of the state of the art of LCA research into citrus fruits. We aim to identify the main methodological decisions, paying special attention to crop cycle modelling and regional representability. Bearing this in mind, we propose recommendations for a harmonised application of LCA on citrus fruits, identifying areas worthy of further research. The main hotspots of the production process are also identified, to understand where improvement efforts should be directed to. To this end, a two-step search was carried out and a final sample of 23 records was obtained. The production of both pesticides and fertilisers together with their on-field emissions are the main hotspots in the reviewed articles. Regarding areas for further research, a lack of studies into the early stages of citrus fruit production is detected. Farm representativeness, both temporal and spatial, is highlighted as a critical issue when assessing regional fruit production. This implies improving life cycle inventories, namely by using site-specific methods to estimate fertiliser and pesticide emissions, developing regionalized datasets of agricultural inputs, and strengthening water inventories. As to the impact assessment, the estimation of both water scarcity and biodiversity impacts is encouraged, together with the use of regionalised impact characterisation methods. Boosting LCA studies on citrus fruits producing countries outside the European Union along with the use of other sustainability tools can support the development of environmental policies. The results of this review can be beneficial for both LCA practitioners and decision-makers, paving the way for a more responsible and sustainable citrus fruit production.