Showing papers on "Water flow published in 2016"
TL;DR: The ecology and biogeochemistry of stream biofilms are described and the influence of physical and ecological processes on their structure and function are highlighted.
Abstract: Streams and rivers form dense networks, shape the Earth's surface and, in their sediments, provide an immensely large surface area for microbial growth. Biofilms dominate microbial life in streams and rivers, drive crucial ecosystem processes and contribute substantially to global biogeochemical fluxes. In turn, water flow and related deliveries of nutrients and organic matter to biofilms constitute major constraints on microbial life. In this Review, we describe the ecology and biogeochemistry of stream biofilms and highlight the influence of physical and ecological processes on their structure and function. Recent advances in the study of biofilm ecology may pave the way towards a mechanistic understanding of the effects of climate and environmental change on stream biofilms and the biogeochemistry of stream ecosystems.
683 citations
TL;DR: In this paper, the authors review the current knowledge of key physical and hydraulic properties related to the structure of globally available peat soils and briefly discuss their implications for water storage, flow and the migration of solutes.
284 citations
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07 Dec 2016
TL;DR: In this paper, an annular water flow channel is formed between the outer drum and the inner drum front cover, and the volume of the water flow channels ranges from 0.5L to 5L.
Abstract: The invention provides a drum washing machine which comprises an outer drum, an inner drum arranged in the outer drum, and a machine cover with a transparent window, wherein the machine cover is arranged on the outer drum and the inner drum in a covering mode; the inner drum comprises an inner drum body and an inner drum front cover arranged at the front end of the inner drum body, an annular water flow channel is formed between the outer drum and the inner drum front cover, a gap is formed between a starting end of the inner drum front cover and the outer drum, and water flow in the water flow channel flushes the transparent window and circulates to the inner drum after flowing through the gap; and the volume of the water flow channel is 0.5L to 5L. The annular water flow channel is formed between the inner drum front cover and the outer drum of the drum washing machine, and the volume of the water flow channel ranges from 0.5L to 5L, so that water on the outer surface of the inner drum front cover washes the transparent window, the front wall of the outer drum and other positions of the drum washing machine, and a water curtain effect is formed at the transparent window; and therefore, residual laundry detergent and dirt on the transparent window, the front wall of the outer drum and the like can be effectively cleaned, the water flow is circulated to the inner drum of the washing machine, and cleaning effect on clothes in the washing machine is enhanced.
225 citations
TL;DR: It is shown that arterial pulsation caused by pulse wave propagation is an unlikely origin of this hypothetical driving force, but it is also shown that such pulsation may still lead to fast para-arterial solute transport through dispersion, that is, through the combined effect of local mixing and diffusion in the para- arterial space.
Abstract: Observations of fast transport of fluorescent tracers in mouse brains have led to the hypothesis of bulk water flow directed from arterial to venous paravascular spaces (PVS) through the cortical interstitium. At the same time, there is evidence for interstitial solute transport by diffusion rather than by directed bulk fluid motion. It has been shown that the two views may be consolidated by intracellular water flow through astrocyte networks combined with mainly diffusive extracellular transport of solutes. This requires the presence of a driving force that has not been determined to date, but for which arterial pulsation has been suggested as the origin. Here we show that arterial pulsation caused by pulse wave propagation is an unlikely origin of this hypothetical driving force. However, we further show that such pulsation may still lead to fast para-arterial solute transport through dispersion, that is, through the combined effect of local mixing and diffusion in the para-arterial space.
219 citations
TL;DR: It is concluded that eDNA generally provides a ‘snapshot’ of fish distribution and biomass in a large area and a best-fit model included echo intensity obtained within 10–150 m from water sampling sites, indicating that the estimated eDNA concentration most likely reflects fish biomass within 150 m in the bay.
Abstract: Recent studies in streams and ponds have demonstrated that the distribution and biomass of aquatic organisms can be estimated by detection and quantification of environmental DNA (eDNA). In more open systems such as seas, it is not evident whether eDNA can represent the distribution and biomass of aquatic organisms because various environmental factors (e.g., water flow) are expected to affect eDNA distribution and concentration. To test the relationships between the distribution of fish and eDNA, we conducted a grid survey in Maizuru Bay, Sea of Japan, and sampled surface and bottom waters while monitoring biomass of the Japanese jack mackerel (Trachurus japonicus) using echo sounder technology. A linear model showed a high R(2) value (0.665) without outlier data points, and the association between estimated eDNA concentrations from the surface water samples and echo intensity was significantly positive, suggesting that the estimated spatial variation in eDNA concentration can reflect the local biomass of the jack mackerel. We also found that a best-fit model included echo intensity obtained within 10-150 m from water sampling sites, indicating that the estimated eDNA concentration most likely reflects fish biomass within 150 m in the bay. Although eDNA from a wholesale fish market partially affected eDNA concentration, we conclude that eDNA generally provides a 'snapshot' of fish distribution and biomass in a large area. Further studies in which dynamics of eDNA under field conditions (e.g., patterns of release, degradation, and diffusion of eDNA) are taken into account will provide a better estimate of fish distribution and biomass based on eDNA.
199 citations
TL;DR: An alternative theory is developed in which plants maximize carbon gain without pricing water loss and is consistent with plant competition because it yields an evolutionary stable strategy (ESS)—species with the ESS stomatal behavior that will outcompete all others.
Abstract: For over 40 y the dominant theory of stomatal behavior has been that plants should open stomates until the carbon gained by an infinitesimal additional opening balances the additional water lost times a water price that is constant at least over short periods This theory has persisted because of its remarkable success in explaining strongly supported simple empirical models of stomatal conductance, even though we have also known for over 40 y that the theory is not consistent with competition among plants for water We develop an alternative theory in which plants maximize carbon gain without pricing water loss and also add two features to both this and the classical theory, which are strongly supported by empirical evidence: (i) water flow through xylem that is progressively impaired as xylem water potential drops and (ii) fitness or carbon costs associated with low water potentials caused by a variety of mechanisms, including xylem damage repair We show that our alternative carbon-maximization optimization is consistent with plant competition because it yields an evolutionary stable strategy (ESS)—species with the ESS stomatal behavior that will outcompete all others We further show that, like the classical theory, the alternative theory also explains the functional forms of empirical stomatal models We derive ways to test between the alternative optimization criteria by introducing a metric—the marginal xylem tension efficiency, which quantifies the amount of photosynthesis a plant will forego from opening stomatal an infinitesimal amount more to avoid a drop in water potential
194 citations
TL;DR: In this paper, the dendritic microstructure, crystal orientation and hot cracking behavior were studied by using optical microscopy, scanning electron microscopy (SEM) and electron backscatter diffraction (EBSD) techniques.
189 citations
TL;DR: The structure and dynamics of water confined between two parallel graphene layers are studied using equilibrium molecular dynamics simulations and it is found that the shear viscosity is not only greatly enhanced for subnanometer capillaries, but also exhibits large oscillations that originate from commensurability between the capillary size and the size of water molecules.
Abstract: The rate of water flow through hydrophobic nanocapillaries is greatly enhanced as compared to that expected from macroscopic hydrodynamics. This phenomenon is usually described in terms of a relatively large slip length, which is in turn defined by such microscopic properties as the friction between water and capillary surfaces and the viscosity of water. We show that the viscosity of water and, therefore, its flow rate are profoundly affected by the layered structure of confined water if the capillary size becomes less than 2 nm. To this end, we study the structure and dynamics of water confined between two parallel graphene layers using equilibrium molecular dynamics simulations. We find that the shear viscosity is not only greatly enhanced for subnanometer capillaries, but also exhibits large oscillations that originate from commensurability between the capillary size and the size of water molecules. Such oscillating behavior of viscosity and, consequently, the slip length should be taken into account in designing and studying graphene-based and similar membranes for desalination and filtration.
185 citations
TL;DR: This study constrains uncertainty about response times and mechanisms controlling glacier and runoff response to climate and sets a benchmark for process-based modeling of the climate change impact on the hydrology of high-altitude catchments.
Abstract: Mountain ranges are the world's natural water towers and provide water resources for millions of people. However, their hydrological balance and possible future changes in river flow remain poorly understood because of high meteorological variability, physical inaccessibility, and the complex interplay between climate, cryosphere, and hydrological processes. Here, we use a state-of-the art glacio-hydrological model informed by data from high-altitude observations and the latest climate change scenarios to quantify the climate change impact on water resources of two contrasting catchments vulnerable to changes in the cryosphere. The two study catchments are located in the Central Andes of Chile and in the Nepalese Himalaya in close vicinity of densely populated areas. Although both sites reveal a strong decrease in glacier area, they show a remarkably different hydrological response to projected climate change. In the Juncal catchment in Chile, runoff is likely to sharply decrease in the future and the runoff seasonality is sensitive to projected climatic changes. In the Langtang catchment in Nepal, future water availability is on the rise for decades to come with limited shifts between seasons. Owing to the high spatiotemporal resolution of the simulations and process complexity included in the modeling, the response times and the mechanisms underlying the variations in glacier area and river flow can be well constrained. The projections indicate that climate change adaptation in Central Chile should focus on dealing with a reduction in water availability, whereas in Nepal preparedness for flood extremes should be the policy priority.
147 citations
TL;DR: In this article, the integration of both medium with the conventional photovoltaic thermal (PV/T) solar collector is presented, and the performance of the system is calculated based on Hottel-Whillier-Bliss equation.
132 citations
TL;DR: In this article, the authors focus on ecosystem recolonization by the biota and their functioning and separate Type A Ecoengineering, where the physico-chemical structure is modified on the basis that ecological structure and functioning will then follow, and Type B Ecoengineering where the Biota are engineered directly such as through restocking or replanting, where suitable physical conditions, especially hydrography and sedimentology, are created to recover estuarine ecology by natural or human-mediated colonisation of primary producers and consumers.
Abstract: Ecological Engineering (or Ecoengineering) is increasingly used in estuaries to re-create and restore ecosystems degraded by human activities, including reduced water flow or land poldered for agricultural use. Here we focus on ecosystem recolonization by the biota and their functioning and we separate Type A Ecoengineering where the physico-chemical structure is modified on the basis that ecological structure and functioning will then follow, and Type B Ecoengineering where the biota are engineered directly such as through restocking or replanting. Modifying the physical system to create and restore natural processes and habitats relies on successfully applying Ecohydrology, where suitable physical conditions, especially hydrography and sedimentology, are created to recover estuarine ecology by natural or human-mediated colonisation of primary producers and consumers, or habitat creation. This successional process then allows wading birds and fish to reoccupy the rehabilitated areas, thus restoring the natural food web and recreating nursery areas for aquatic biota. We describe Ecohydrology principles applied during Ecoengineering restoration projects in Europe, Australia, Asia, South Africa and North America. These show some successful and sustainable approaches but also others that were less than successful and not sustainable despite the best of intentions (and which may even have harmed the ecology). Some schemes may be ‘good for the ecologists’, as conservationists consider it successful that at least some habitat was created, albeit in the short-term, but arguably did little for the overall ecology of the area in space or time. We indicate the trade-offs between the short- and long-term value of restored and created ecosystems, the success at developing natural structure and functioning in disturbed estuaries, the role of this in estuarine and wetland management, and the costs and benefits of Ecoengineering to the socio-ecological system. These global case studies provide important lessons for both the science and management of estuaries, including that successful estuarine restoration is a complex and often difficult process, and that Ecoengineering with Ecohydrology aims to control and/or simulate natural ecosystem processes.
TL;DR: In this article, the authors present numerical modeling results and flux experiments for conductive gap membrane distillation (CGMD), as well as permeate gap membrane disentillation (PGMD), and validate the numerical models for PGMD and CGMD.
TL;DR: In this article, the authors proposed to decrease the uncertainty of GHM output by making better use of in situ and remotely sensed observations of output variables such as river discharge or total water storage variations by multi-criteria validation, calibration or data assimilation.
Abstract: Quantification of spatially and temporally resolved water flows and water storage variations for all land areas of the globe is required to assess water resources, water scarcity and flood hazards, and to understand the Earth system. This quantification is done with the help of global hydrological models (GHMs). What are the challenges and prospects in the development and application of GHMs? Seven important challenges are presented. (1) Data scarcity makes quantification of human water use difficult even though significant progress has been achieved in the last decade. (2) Uncertainty of meteorological input data strongly affects model outputs. (3) The reaction of vegetation to changing climate and CO2 concentrations is uncertain and not taken into account in most GHMs that serve to estimate climate change impacts. (4) Reasons for discrepant responses of GHMs to changing climate have yet to be identified. (5) More accurate estimates of monthly time series of water availability and use are needed to provide good indicators of water scarcity. (6) Integration of gradient-based groundwater modelling into GHMs is necessary for a better simulation of groundwater–surface water interactions and capillary rise. (7) Detection and attribution of human interference with freshwater systems by using GHMs are constrained by data of insufficient quality but also GHM uncertainty itself. Regarding prospects for progress, we propose to decrease the uncertainty of GHM output by making better use of in situ and remotely sensed observations of output variables such as river discharge or total water storage variations by multi-criteria validation, calibration or data assimilation. Finally, we present an initiative that works towards the vision of hyperresolution global hydrological modelling where GHM outputs would be provided at a 1-km resolution with reasonable accuracy.
TL;DR: In this article, the authors constructed a model of a GO membrane using laminate nanochannels with aligned flexible multilayered GO sheets, on which functional groups were randomly distributed based on the Lerf-Klinowski model.
Abstract: Layer-by-layer assembled graphene oxide (GO) has been considered as a high-efficiency novel membrane material. However, its performance of water permeation and ion rejection remains largely unresolved. Herein we constructed a model of a GO membrane using laminate nanochannels with aligned flexible multilayered GO sheets, on which functional groups were randomly distributed based on the Lerf–Klinowski model. The water permeation and ion rejection in the flexible GO membranes with various pore widths and surface oxidization degrees were simulated. Our results indicate water flow rate in the GO nanochannels is significantly slowed, which is quantitatively equivalent with the prediction using the no-slip Poiseuille equation. The simulated results suggest the capillary channels within GO stacked laminated membranes might not always work as the major flow route for water to permeate. It is observed that confined water structure becomes more disordered and loose within the corrugated GO nanochannels. The interfa...
TL;DR: In this article, the porosities of hydrate-bearing porous media formed by different-size particles, as calculated by both the pore network models and the volumetric method, are in agreement.
TL;DR: In this paper, the authors reviewed the progress made in incorporating human factors in large-scale hydrological models and their integration into Earth system models, focusing primarily on the recent advancements and existing challenges in integrating human impacts in global land surface models.
Abstract: The global water cycle has been profoundly affected by human land–water management. As the changes in the water cycle on land can affect the functioning of a wide range of biophysical and biogeochemical processes of the Earth system, it is essential to represent human land–water management in Earth system models (ESMs). During the recent past, noteworthy progress has been made in large-scale modeling of human impacts on the water cycle but sufficient advancements have not yet been made in integrating the newly developed schemes into ESMs. This study reviews the progresses made in incorporating human factors in large-scale hydrological models and their integration into ESMs. The study focuses primarily on the recent advancements and existing challenges in incorporating human impacts in global land surface models (LSMs) as a way forward to the development of ESMs with humans as integral components, but a brief review of global hydrological models (GHMs) is also provided. The study begins with the general overview of human impacts on the water cycle. Then, the algorithms currently employed to represent irrigation, reservoir operation, and groundwater pumping are discussed. Next, methodological deficiencies in current modeling approaches and existing challenges are identified. Furthermore, light is shed on the sources of uncertainties associated with model parameterizations, grid resolution, and datasets used for forcing and validation. Finally, representing human land–water management in LSMs is highlighted as an important research direction toward developing integrated models using ESM frameworks for the holistic study of human–water interactions within the Earths system.
TL;DR: In this article, the waste heat recovery performance of a thermoelectric generator (TEG) was experimentally investigated, where 40 customized TEMs were installed on the upper and lower sides of a rectangular exhaust gas channel in a 4 × 5 arrangement.
TL;DR: Pervious concrete (PC) mixtures were designed and prepared to measure and study permeability characteristics at varying head levels using a falling head permeameter, and a total of 1092 readings were used to study the permeability properties of eighteen PC mixtures whose porosity was in the range of 15-37%, and permeability in the realm of 0.076-3.5 cm/s as mentioned in this paper.
TL;DR: It is shown that eDNA technology can be effectively used in tropical ecosystems to detect invasive fish species and established a minimum detection limit for tilapia, and high water temperatures did not affect eDNA degradation rates.
Abstract: Invasive species pose a major threat to aquatic ecosystems. Their impact can be particularly severe in tropical regions, like those in northern Australia, where >20 invasive fish species are recorded. In temperate regions, environmental DNA (eDNA) technology is gaining momentum as a tool to detect aquatic pests, but the technology's effectiveness has not been fully explored in tropical systems with their unique climatic challenges (i.e. high turbidity, temperatures and ultraviolet light). In this study, we modified conventional eDNA protocols for use in tropical environments using the invasive fish, Mozambique tilapia (Oreochromis mossambicus) as a detection model. We evaluated the effects of high water temperatures and fish density on the detection of tilapia eDNA, using filters with larger pores to facilitate filtration. Large-pore filters (20 μm) were effective in filtering turbid waters and retaining sufficient eDNA, whilst achieving filtration times of 2-3 min per 2-L sample. High water temperatures, often experienced in the tropics (23, 29, 35 °C), did not affect eDNA degradation rates, although high temperatures (35 °C) did significantly increase fish eDNA shedding rates. We established a minimum detection limit for tilapia (1 fish/0.4 megalitres/after 4 days) and found that low water flow (3.17 L/s) into ponds with high fish density (>16 fish/0.4 megalitres) did not affect eDNA detection. These results demonstrate that eDNA technology can be effectively used in tropical ecosystems to detect invasive fish species. © 2016 John Wiley & Sons Ltd.
TL;DR: In this article, the authors derived time variable travel time distributions for 35 study sites within the Attert catchment in Luxembourg using the soil physical model HYDRUS-1D, and tracked the water parcels introduced with each rainfall event over a period of several years.
Abstract: Water travel times reflect hydrological processes, yet we know little about how travel times in the unsaturated zone vary with time. Using the soil physical model HYDRUS-1D, we derived time variable travel time distributions for 35 study sites within the Attert catchment in Luxembourg. While all sites experience similar climatic forcing, they differ with regard to soil types (16 Cambisols, 12 Arenosols, and 7 Stagnosols) and the vegetation cover (29 forest and 6 grassland). We estimated site specific water flow and transport parameters by fitting the model simulations to observed soil moisture time series and depth profiles of pore water stable isotopes. With the calibrated model, we tracked the water parcels introduced with each rainfall event over a period of several years. Our results show that the median travel time of water from the soil surface to depths down to 200 cm is mainly driven by the subsequent rainfall amounts. The median time until precipitation is taken up by roots is governed by the seasonality of evapotranspiration rates. The ratio between the amount of water that leaves the soil profile by on the one hand and evaporation and transpiration on the other hand also shows an annual cycle. This time variable response due to climatic forcing is furthermore visible in the multimodal nature of the site specific master transit time distribution representing the flow-averaged probability density for rainwater to become recharge. The spatial variability of travel times is mainly driven by soil texture and structure, with significant longer travel times for the clayey Stagnosols than for the loamy to sandy Cambisols and Arenosols.
TL;DR: In this article, the authors investigated the spatiotemporal variations of blue and green water resources under different land use change, agricultural irrigation expansion and climate variability scenarios during the 1980s-2000s for the Weihe River Basin.
Abstract: Background Land use change and climate variability influence water resources availability and separation of these influences are important for water resources management. Methods SWAT model and the Mann–Kendall method were used in this study which investigated the spatiotemporal variations of blue and green water resources under different land use change, agricultural irrigation expansion and climate variability scenarios during the 1980s–2000s for the Weihe River Basin. Results Farmland area decreased by 1.4% and woodland, grassland, and construction land area increased by 0.6%, 0.2%, and 0.6%, respectively. The combined impact of land use change, agricultural irrigation expansion and climate variation decreased the blue water flow, green water flow, and green water storage by 21.62 mm year− 1, 35.01 mm year− 1 and 28.07 mm year− 1, respectively. Climate variability decreased the blue/green water flow and green water storage, land use change decreased the blue water and green water flow while it increased the green water storage, irrigation expansion decreased the blue water flow while it increased the green water flow/storage. The spatial distribution showed an uneven change in the Weihe River Basin. Together, we suggested that the variability of water resources availability in the Weihe River Basin was mainly attributed to climate variability, while land use change plays a key role in the sub-basins which experienced dramatic changes in land use.
TL;DR: It is demonstrated that a recreational drone can be used to yield accurate surface flow maps of sub-meter water bodies and this first instance of quantitative water flow sensing from a flying drone paves the way to novel observations of the environment.
TL;DR: In this paper, a series of studies were conducted to determine a suitable site for enhanced geothermal systems (EGSs) in mainland China, and a hydraulic fracturing model based on real geological and logging data of well YS-2 and field fracturing experience in this region was established, and the geometric dimension and flow conductivity of the induced fracture were imported into a 3D hydrothermal coupled model established using TOUGH2-EOS1.
Abstract: A series of studies was conducted to determine a suitable site for enhanced geothermal systems (EGSs) in mainland China. First, the Xujiaweizi (XJWZ) area in the Songliao Basin in northeastern China was identified to possess several features indicating a huge potential for hot dry rock (HDR) resource development from the aspects of tectonics, geology, geophysics, and geothermics. Then, a hydraulic fracturing model based on the real geological and logging data of well YS-2 and field fracturing experience in this region was established, and the geometric dimension and flow conductivity of the induced fracture were imported into a 3D hydrothermal coupled model established using TOUGH2-EOS1. The electricity generation potential of the fractured reservoir using three horizontal well production patterns is evaluated. Finally, three enhanced methods are proposed and discussed based on the simulation results. Results indicate that HDR resources in the XJWZ area demonstrate a significant potential for development from the aspect of geology. The Yingcheng Formation is selected as the potential target formation. The gel-proppant fracturing method is adopted in consideration of the undeveloped natural fractures in the target formation. The generalized EGS reservoir region possessed a considerable length of 600 m. The maximum production flow rate is determined to be 1 kg/s. The water flow impedance is relatively high during the heat production process for economic exploitation. Such an EGS reservoir has poor electricity generation capacity. A naturally fractured reservoir with a higher temperature should be targeted for electricity generation.
01 Dec 2016
TL;DR: In this article, an arduino based controlled irrigation system is proposed and demonstrated for the CCA of farming, which deals with various environmental factors such as moisture, temperature and amount of water required by the crops using sensors like water flow sensor, temperature sensor and soil moisture sensor.
Abstract: Emergence of Controlled Environment Agriculture (CEA) ranging from computer controlled water irrigation system to lightning and ventilation has changed the conventional scenario of farming. This paper proposes and demonstrate an economical and easy to use arduino based controlled irrigation system. The designed system deals with various environmental factors such as moisture, temperature and amount of water required by the crops using sensors like water flow sensor, temperature sensor and soil moisture sensor. Datas are collected and received by arduino which can be linked to an interactive website which show the real time values along with the standard values of different factor required by a crop. This allows user to control irrigation pumps and sprinklers from far distance through a website and to meet the standard values which would help the farmer to yield maximum and quality crops. Studies conducted on laboratory prototype suggested the designed system to be applicable which can be implemented.
TL;DR: A constitutive model is proposed that captures compression stiffening, tension softening, and shear softening in liver mechanics, and can be understood in terms of the cellular and matrix components of the liver.
Abstract: Tissues including liver stiffen and acquire more extracellular matrix with fibrosis. The relationship between matrix content and stiffness, however, is non-linear, and stiffness is only one component of tissue mechanics. The mechanical response of tissues such as liver to physiological stresses is not well described, and models of tissue mechanics are limited. To better understand the mechanics of the normal and fibrotic rat liver, we carried out a series of studies using parallel plate rheometry, measuring the response to compressive, extensional, and shear strains. We found that the shear storage and loss moduli G' and G" and the apparent Young's moduli measured by uniaxial strain orthogonal to the shear direction increased markedly with both progressive fibrosis and increasing compression, that livers shear strain softened, and that significant increases in shear modulus with compressional stress occurred within a range consistent with increased sinusoidal pressures in liver disease. Proteoglycan content and integrin-matrix interactions were significant determinants of liver mechanics, particularly in compression. We propose a new non-linear constitutive model of the liver. A key feature of this model is that, while it assumes overall liver incompressibility, it takes into account water flow and solid phase compressibility. In sum, we report a detailed study of non-linear liver mechanics under physiological strains in the normal state, early fibrosis, and late fibrosis. We propose a constitutive model that captures compression stiffening, tension softening, and shear softening, and can be understood in terms of the cellular and matrix components of the liver.
TL;DR: In this article, the authors used a multi-model ensemble to show the potential impacts of climate change on global hydropower and cooling water discharge potential, and combined projections of streamflow and water temperature were produced with three global hydrological models (GHMs) to account for uncertainties in the structure and parametrization of these GHMs in both water availability and temperature.
Abstract: Worldwide, 98% of total electricity is currently produced by thermoelectric power and hydropower. Climate change is expected to directly impact electricity supply, in terms of both water availability for hydropower generation and cooling water usage for thermoelectric power. Improved understanding of how climate change may impact the availability and temperature of water resources is therefore of major importance. Here we use a multi-model ensemble to show the potential impacts of climate change on global hydropower and cooling water discharge potential. For the first time, combined projections of streamflow and water temperature were produced with three global hydrological models (GHMs) to account for uncertainties in the structure and parametrization of these GHMs in both water availability and water temperature. The GHMs were forced with bias-corrected output of five general circulation models (GCMs) for both the lowest and highest representative concentration pathways (RCP2.6 and RCP8.5). The ensemble projections of streamflow and water temperature were then used to quantify impacts on gross hydropower potential and cooling water discharge capacity of rivers worldwide. We show that global gross hydropower potential is expected to increase between +2.4% (GCM-GHM ensemble mean for RCP 2.6) and +6.3% (RCP 8.5) for the 2080s compared to 1971–2000. The strongest increases in hydropower potential are expected for Central Africa, India, central Asia and the northern high-latitudes, with 18–33% of the world population living in these areas by the 2080s. Global mean cooling water discharge capacity is projected to decrease by 4.5-15% (2080s). The largest reductions are found for the United States, Europe, eastern Asia, and southern parts of South America, Africa and Australia, where strong water temperature increases are projected combined with reductions in mean annual streamflow. These regions are expected to affect 11–14% (for RCP2.6 and the shared socio-economic pathway (SSP)1, SSP2, SSP4) and 41–51% (RCP8.5–SSP3, SSP5) of the world population by the 2080s.
TL;DR: This is the first demonstration of the presence of two conjugated metabolites ofacetaminophen, acetaminophen glucuronide and acetamine sulfate, as well as of loxoprofen and loxobrofen alcohol, in hospital effluent, STP, and river waters.
TL;DR: In this paper, an investigation is carried out to determine how air and water flow rates as well as the air inlet size (variable parameters) influence the size distribution of micro bubbles for a Venturi type bubble generator.
TL;DR: In this paper, a two-phase Smoothed Particle Hydrodynamics (SPH) method is used to simulate the fluid-structure interactions with violent deformation of the free surface.
TL;DR: Evidence for large-scale subglacial water flow in Antarctica is reviewed, including the discovery of ancient channels developed by former hydrological processes, and areas where future discoveries may be possible are predicted.
Abstract: It is now well documented that over 400 subglacial lakes exist across the bed of the Antarctic Ice Sheet. They comprise a variety of sizes and volumes (from the approx. 250 km long Lake Vostok to bodies of water less than 1 km in length), relate to a number of discrete topographic settings (from those contained within valleys to lakes that reside in broad flat terrain) and exhibit a range of dynamic behaviours (from ‘active’ lakes that periodically outburst some or all of their water to those isolated hydrologically for millions of years). Here we critique recent advances in our understanding of subglacial lakes, in particular since the last inventory in 2012. We show that within 3 years our knowledge of the hydrological processes at the ice-sheet base has advanced considerably. We describe evidence for further ‘active’ subglacial lakes, based on satellite observation of ice-surface changes, and discuss why detection of many ‘active’ lakes is not resolved in traditional radio-echo sounding methods. We go on to review evidence for large-scale subglacial water flow in Antarctica, including the discovery of ancient channels developed by former hydrological processes. We end by predicting areas where future discoveries may be possible, including the detection, measurement and significance of groundwater (i.e. water held beneath the ice-bed interface).