scispace - formally typeset
Search or ask a question

Showing papers on "Water flow published in 2019"


Book ChapterDOI
01 Jan 2019
TL;DR: In this article, sediment is either loaded as bed-load with particles sliding, saltating, and rolling over the river bed, or as a suspended-load, where particles move with the turbulent water flow away from the bed.
Abstract: Transportation of sediment is an important and frequent phenomenon in rivers. Sediment is mobilized as bed-load with particles sliding, saltating, and rolling over the river bed, or as a suspended-load, where particles move with the turbulent water flow away from the bed.

13,877 citations


Journal ArticleDOI
Chuan Xia1, Yang Xia1, Peng Zhu1, Lei Fan1, Haotian Wang1 
11 Oct 2019-Science
TL;DR: A direct electrosynthesis strategy that delivers separate hydrogen (H2) and oxygen (O2) streams to an anode and cathode separated by a porous solid electrolyte, wherein the electrochemically generated H+ and HO2– recombine to form pure aqueous H2O2 solutions.
Abstract: Hydrogen peroxide (H2O2) synthesis generally requires substantial postreaction purification. Here, we report a direct electrosynthesis strategy that delivers separate hydrogen (H2) and oxygen (O2) streams to an anode and cathode separated by a porous solid electrolyte, wherein the electrochemically generated H+ and HO2– recombine to form pure aqueous H2O2 solutions. By optimizing a functionalized carbon black catalyst for two-electron oxygen reduction, we achieved >90% selectivity for pure H2O2 at current densities up to 200 milliamperes per square centimeter, which represents an H2O2 productivity of 3.4 millimoles per square centimeter per hour (3660 moles per kilogram of catalyst per hour). A wide range of concentrations of pure H2O2 solutions up to 20 weight % could be obtained by tuning the water flow rate through the solid electrolyte, and the catalyst retained activity and selectivity for 100 hours.

445 citations


Journal ArticleDOI
TL;DR: Estuarine conservation plans should consider year-round fluctuations of the ecocline and the resulting cycles of retention and flush of environmental signals and their influence on trophic webs over the whole extent of estuarine gradients.

219 citations


Journal ArticleDOI
TL;DR: Applications of circuit theory to the science and practice of connectivity conservation, including topics in landscape and population genetics, movement and dispersal paths of organisms, anthropogenic barriers to connectivity, fire behavior, water flow, and ecosystem services, are focused on.
Abstract: Conservation practitioners have long recognized ecological connectivity as a global priority for preserving biodiversity and ecosystem function. In the early years of conservation science, ecologists extended principles of island biogeography to assess connectivity based on source patch proximity and other metrics derived from binary maps of habitat. From 2006 to 2008, the late Brad McRae introduced circuit theory as an alternative approach to model gene flow and the dispersal or movement routes of organisms. He posited concepts and metrics from electrical circuit theory as a robust way to quantify movement across multiple possible paths in a landscape, not just a single least-cost path or corridor. Circuit theory offers many theoretical, conceptual, and practical linkages to conservation science. We reviewed 459 recent studies citing circuit theory or the open-source software Circuitscape. We focused on applications of circuit theory to the science and practice of connectivity conservation, including topics in landscape and population genetics, movement and dispersal paths of organisms, anthropogenic barriers to connectivity, fire behavior, water flow, and ecosystem services. Circuit theory is likely to have an effect on conservation science and practitioners through improved insights into landscape dynamics, animal movement, and habitat-use studies and through the development of new software tools for data analysis and visualization. The influence of circuit theory on conservation comes from the theoretical basis and elegance of the approach and the powerful collaborations and active user community that have emerged. Circuit theory provides a springboard for ecological understanding and will remain an important conservation tool for researchers and practitioners around the globe.

193 citations


Journal ArticleDOI
TL;DR: The evidence for the biophysical conditions necessary for foliar water uptake to occur is reviewed, focusing on the plant and atmospheric water potentials necessary to create a gradient for water flow and the different pathways for uptake, as well as the potential fates of the water once inside the leaf.
Abstract: Nearly all plant families, represented across most major biomes, absorb water directly through their leaves This phenomenon is commonly referred to as foliar water uptake Recent studies have suggested that foliar water uptake provides a significant water subsidy that can influence both plant water and carbon balance across multiple spatial and temporal scales Despite this, our mechanistic understanding of when, where, how, and to what end water is absorbed through leaf surfaces remains limited We first review the evidence for the biophysical conditions necessary for foliar water uptake to occur, focusing on the plant and atmospheric water potentials necessary to create a gradient for water flow We then consider the different pathways for uptake, as well as the potential fates of the water once inside the leaf Given that one fate of water from foliar uptake is to increase leaf water potentials and contribute to the demands of transpiration, we also provide a quantitative synthesis of observed rates of change in leaf water potential and total fluxes of water into the leaf Finally, we identify critical research themes that should be addressed to effectively incorporate foliar water uptake into traditional frameworks of plant water movement

149 citations


Journal ArticleDOI
TL;DR: In this article, the authors reviewed 347 significant publications from 2000 to 2017 from the ISI Web of Knowledge database to discuss the effects of dam construction on biodiversity in freshwater wetlands and identify the future directions for research in this field.

149 citations


Journal ArticleDOI
TL;DR: The ability of eDNA metabarcoding surveys to distinguish localized signals obtained from four marine habitats within a small spatial scale (<5 km) subject to significant tidal and along‐shore water flow is determined.
Abstract: While in recent years environmental DNA (eDNA) metabarcoding surveys have shown great promise as an alternative monitoring method, the integration into existing marine monitoring programs may be confounded by the dispersal of the eDNA signal. Currents and tidal influences could transport eDNA over great distances, inducing false-positive species detection, leading to inaccurate biodiversity assessments and, ultimately, mismanagement of marine environments. In this study, we determined the ability of eDNA metabarcoding surveys to distinguish localized signals obtained from four marine habitats within a small spatial scale (<5 km) subject to significant tidal and along-shore water flow. Our eDNA metabarcoding survey detected 86 genera, within 77 families and across 11 phyla using three established metabarcoding assays targeting fish (16S rRNA gene), crustacean (16S rRNA gene) and eukaryotic (cytochrome oxidase subunit 1) diversity. Ordination and cluster analyses for both taxonomic and OTU data sets show distinct eDNA signals between the sampled habitats, suggesting dispersal of eDNA among habitats was limited. Individual taxa with strong habitat preferences displayed localized eDNA signals in accordance with their respective habitat, whereas taxa known to be less habitat-specific generated more ubiquitous signals. Our data add to evidence that eDNA metabarcoding surveys in marine environments detect a broad range of taxa that are spatially discrete. Our work also highlights that refinement of assay choice is essential to realize the full potential of eDNA metabarcoding surveys in marine biodiversity monitoring programs.

140 citations


Journal ArticleDOI
TL;DR: The authors report on the growth of zeolites on cotton fibres with high stability and haemostatic ability, and an on-site template-free growth route that tightly binds mesoporous single-crystal chabazite zeolite onto the surface of cotton fibers.
Abstract: Achieving rapid definitive hemostasis is essential to ensure survival of patients with massive bleeding in pre-hospital care. It is however challenging to develop hemostatic agents or dressings that simultaneously deliver a fast, long-lasting and safe treatment of hemorrhage. Here, we integrate meso-/micro-porosity, blood coagulation and stability into a flexible zeolite-cotton hybrid hemostat. We employ an on-site template-free growth route that tightly binds mesoporous single-crystal chabazite zeolite onto the surface of cotton fibers. This hemostatic material maintains high procoagulant activity after water flow treatment. Chabazite particles are firmly anchored onto the cotton surface with < 1% leaching after 10 min of sonication. The as-synthesized hemostatic device has superior hemostatic performance over most other clay or zeolite-based inorganic hemostats, in terms of higher procoagulant activity, minimized loss of active components and better scalability for practical applications (a hemostatic T-shirt is hereby demonstrated as an example). Zeolites have attracted attention and have been applied as haemostatic agents; however, there are issues associated with released zeolite powder. Here, the authors report on the growth of zeolites on cotton fibres with high stability and haemostatic ability.

136 citations


Journal ArticleDOI
TL;DR: In this article, the state-of-the-art cooling methods of photovoltaic (PV) modules and the performance of the radiative cooling method in detail are evaluated.
Abstract: This paper reviews the state-of-the-art cooling methods of photovoltaic (PV) modules and evaluates the performance of the radiative cooling method in detail. Higher operating temperatures of PV modules cause degradation of conversion efficiency and long-term reliability. To overcome this drawback, active or passive cooling methods using heat pipe, natural/forced air flow, forced water flow, phase change material, direct liquid immersion/submerging, and passive heat sink have been studied. In this paper, the methodologies and cooling effects of various cooling methods in the literature are summarized to provide a comprehensive overview of the current cooling technologies. Then, the performance of the radiative cooling method, which is simple and passive (zero power consumption) method, is quantitatively evaluated based on a detailed heat transfer model considering sky radiation properties in four typical climate conditions. Daily heat budgets of the PV modules with different surface emissivity spectra are simulated to estimate the solar cell temperature. The results indicate that modification of the surface emissivity spectrum hardly contribute to the radiative cooling enhancement under any climate conditions, as compared to the conventional glass cover. The present findings serve as a guide for future research and development of better cooling methods.

118 citations


Journal ArticleDOI
TL;DR: In this article, an optimization model for cascade hydropower stations coupled with renewable energy-based power generation methods such as wind and photovoltaics (PV) is proposed.

112 citations


Journal ArticleDOI
TL;DR: In this article, an integrated design of PCM and cooling plate has been proposed for preventing heat propagation and thermal runaway in a battery module made of 18,650 cells that have been damaged by nail penetration of upto three cells.

Journal ArticleDOI
TL;DR: In this paper, the effect of nanoparticle shape on the entropy generation characteristics of boehmite alumina nanofluid flowing through a horizontal double-pipe minichannel heat exchanger was studied.
Abstract: This paper aims to study the effect of nanoparticle shape on the entropy generation characteristics of boehmite alumina nanofluid flowing through a horizontal double-pipe minichannel heat exchanger. Boehmite alumina ( γ -AlOOH) nanoparticles of different shapes (cylindrical, brick, blade, platelet, and spherical) are dispersed in a mixture of water/ethylene glycol as the nanofluid. The nanofluid and water flow in the tube side and annulus side of the heat exchanger, respectively. The effects of the Reynolds number and nanoparticle concentration on the frictional entropy generation rate, thermal entropy generation rate, total entropy generation rate and Bejan number are numerically analyzed for different nanoparticle shapes. The obtained results demonstrated that the nanofluids containing platelet shape and spherical shape nanoparticles have the highest and lowest rates of thermal, frictional, and total entropy generation, respectively. Additionally, it was found that the rates of thermal, frictional, and total entropy generation increase with an increase in the Reynolds number, while the opposite is true for the Bejan number. Furthermore, it was inferred from the obtained results that the increase of nanoparticle concentration results in higher frictional and total entropy generation rates and lower Bejan number.

Journal ArticleDOI
05 Apr 2019-PLOS ONE
TL;DR: Water temperature is a key factor affecting phytoplankton bloom dynamics in shallow productive coastal waters and could become crucial with future global warming by modifying bloom phenology and changing phy Topolankton community structure, in turn affecting the entire food web and ecosystem services.
Abstract: Phytoplankton blooms are an important, widespread phenomenon in open oceans, coastal waters and freshwaters, supporting food webs and essential ecosystem services Blooms are even more important in exploited coastal waters for maintaining high resource production However, the environmental factors driving blooms in shallow productive coastal waters are still unclear, making it difficult to assess how environmental fluctuations influence bloom phenology and productivity To gain insights into bloom phenology, Chl a fluores-cence and meteorological and hydrological parameters were monitored at high-frequency (15 min) and nutrient concentrations and phytoplankton abundance and diversity, were monitored weekly in a typical Mediterranean shallow coastal system (Thau Lagoon) This study was carried out from winter to late spring in two successive years with different climatic conditions: 2014/2015 was typical, but the winter of 2015/2016 was the warmest on record Rising water temperature was the main driver of phytoplankton blooms However, blooms were sometimes correlated with winds and sometimes correlated with salinity, suggesting nutrients were supplied by water transport via winds, saltier seawater intake, rain and water flow events This finding indicates the joint role of these factors in determining the success of phytoplankton blooms Furthermore, interannual variability showed that winter water temperature was higher in 2016 than in 2015, resulting in lower phytoplankton bio-mass accumulation in the following spring Moreover, the phytoplankton abundances and diversity also changed: cyanobacteria (< 1 μm), picoeukaryotes (< 1 μm) and nanoeukar-yotes (3-6 μm) increased to the detriment of larger phytoplankton such as diatoms Water temperature is a key factor affecting phytoplankton bloom dynamics in shallow productive coastal waters and could become crucial with future global warming by modifying bloom phenology and changing phytoplankton community structure, in turn affecting the entire food web and ecosystem services PLOS ONE | https://doiorg/101371/journalpone

Journal ArticleDOI
TL;DR: Based on the multi-regional input-output model and structural decomposition analysis, this article evaluated the redistribution of water withdrawal within China in 2002, 2007 and 2012, and then revealed the hidden driving forces of the changes in virtual water flows.

Journal ArticleDOI
TL;DR: In this article, a micro and meso-scale geometrical coal model was reconstructed based on X-ray CT imaging and 3D reconstruction technology, and three kinds of uniaxial compression experiments were carried out under displacement loading based on the Mohr-Coulomb constitutive model of LS-DYNA platform.

Journal ArticleDOI
TL;DR: In this article, an evaporation-driven water flow nanogenerator based on a piece of flexible carbon nanoparticle film is presented, which can be tuned from −3 to 3V by manipulating the surface functional groups on the carbon nanoparticles.

Journal ArticleDOI
TL;DR: A highly accurate damage detection method using a deep convolutional neural network with transfer learning using Inception-v3 and trained the network using transfer learning to detect damage.
Abstract: During the long-term operation of hydro-junction infrastructure, water flow erosion causes concrete surfaces to crack, resulting in seepage, spalling, and rebar exposure. To ensure infrastructure safety, detecting such damage is critical. We propose a highly accurate damage detection method using a deep convolutional neural network with transfer learning. First, we collected images from hydro-junction infrastructure using a high-definition camera. Second, we preprocessed the images using an image expansion method. Finally, we modified the structure of Inception-v3 and trained the network using transfer learning to detect damage. The experiments show that the accuracy of the proposed damage detection method is 96.8%, considerably higher than the accuracy of a support vector machine. The results demonstrate that our damage detection method achieves better damage detection performance.

Journal ArticleDOI
Chang Li1, Yufang Liu1, Chunlei Gao1, Xin Li1, Yan Xing1, Yongmei Zheng1 
TL;DR: A novel mechanism revealed that after the nanocone-decorated fiber was wetted, a water film formed and immediately broke up into droplets, owing to the force relating to Rayleigh instability, which realizes the formation of fast continuous water flow, rather than the traditional intermittent course.
Abstract: The bioinspired nanocone-decorated three-dimensional fiber network (N3D) can be fabricated, where an original 3D web is designed, inspired by some newest research findings of spider web, and it is decorated with hydrophilic zinc oxide (ZnO) nanocones inspired by cactus spine. Multilevel high specific surface area exposure on fiber together with the hydrophilic decoration enables it to be more attractive to water molecules. These nanocones can capture fog droplet, generate coalesced droplet, and accordingly make droplet transport efficient because of Laplace pressure difference. Especially, a novel mechanism revealed that after the nanocone-decorated fiber was wetted, that is, a water film formed and immediately broke up into droplets, owing to the force relating to Rayleigh instability. Consequent lower retention surface realizes the formation of fast continuous water flow, rather than the traditional intermittent course. Thus, outstanding fog-harvesting efficiency was achieved on N3D, for example, probab...

Journal ArticleDOI
TL;DR: In this article, a field survey of distresses characterization for an asphalt pavement is firstly introduced and analyzed on the basis of analyzing macro-scale and micro-scale mechanisms of hydraulic scouring, traditional experimental methods for moisture damage evaluation are then discussed.

Journal ArticleDOI
TL;DR: In this paper, the authors discuss the energy management strategies applied for renewable energy fed water pumping system when the system assisted with third energy system (battery bank, fuel cell, etc) to ensure good design, guarantee the control speed required for the motor, regulates the flow of water, assuring accurate operation for all conversion and finally, it maintains precise balance in between the renewable energy generated and power required by the load (pump).
Abstract: Pumping of water requires excessive energy for its operation by consuming a massive amount of diesel, gasoline, electric power etc. The more promising alternative energies to perform the same operation without any energy cost are solar photovoltaic (PV) and wind. These fastest growing renewable energies are more reliable and well suitable for remote villages where there is no possibility of extending transmission lines. Furthermore, these systems are optimal for conditions like only small amount of water needed to be pumped for a particular time. Unlike conventional energy sources of electric power, the renewable energy sources are not dispatchable its power output cannot be controlled. In that case, it involves power conversion stages so that it would necessitate to design an advanced control strategy technique. Those control strategies greatly avoid and protects the system from detrimental operating conditions by monitoring input voltage, water flow, torque, power, pressure, speed and motor vibration etc. Henceforth the use of efficient control strategy not only increase the performance of system it also helps to increase the number of operational hours of solar PV and wind energy systems. In this manuscript, the research work of various control strategies carried out in solar PV and wind energy-based water pumping systems are presented. Additionally, this paper intends to discuss the energy management strategies applied for renewable energy fed water pumping system when the system assisted with third energy system (battery bank, fuel cell, etc). These benefited systems ensure good design, guarantees the control speed required for the motor, regulates the flow of water, assuring accurate operation for all conversion and finally, it maintains precise balance in between the renewable energy generated and power required by the load (pump).

Journal ArticleDOI
TL;DR: In this paper, a piecewise distributed parameter model for the piezoelectric cantilever beam with three types of bluff bodies is proposed, and a modified Van der Pol model is established to simulate the VIV force for the cylinder bluff body, and the quasi-steady hypothesis is used to obtain the galloping hydrodynamic force for tri-prism and semi-cylinder bluff bodies.

Journal ArticleDOI
TL;DR: In this paper, the authors present a kW-scale, 24-hour continuously operational, radiative sky cooling system, with both experimental study and detailed modeling, and quantitatively show how water flow rate directly affects the system cooling power and inversely affects the water temperature drop.

Journal ArticleDOI
TL;DR: In this article, a triple-tube heat exchanger equipped with inserted ribs is presented, where the ribs are installed on the outer surface of the inner tube, and the overall heat transfer coefficient, effectiveness and heat transfer rate of the heat exchange rate are enhanced by increasing the nanoparticle concentration and rib height and decreasing the rib pitch.

Journal ArticleDOI
TL;DR: In this paper, the effect of air supply pressure on atomization characteristics and dust-suppression efficiency of an internal-mixing air-assisted atomizing nozzle was investigated, where the FLUENT software was employed to simulate the flow field inside the nozzle and near the outlet of the nozzle under different air supply pressures.

Journal ArticleDOI
TL;DR: In this paper, a customized experimental spraying platform for dust control was used to study the atomization characteristics and dust reduction performance of the internal-mixing air-assisted atomizer nozzle under different structural parameters.

Journal ArticleDOI
TL;DR: Barley (Hordeum vulgare) is more drought tolerant than other cereals, thus making it an excellent model for the study of the chemical, transcriptomic and physiological effects of water deficit, and osmotic stress enhances cell wall suberization and markedly reduces LPR of the apoplastic pathway, whereas Lpr of the cell‐to‐cell pathway is not altered.
Abstract: Barley (Hordeum vulgare) is more drought tolerant than other cereals, thus making it an excellent model for the study of the chemical, transcriptomic and physiological effects of water deficit. Roots are the first organ to sense soil water deficit. Therefore, we studied the response of barley seminal roots to different water potentials induced by polyethylene glycol (PEG) 8000. We investigated changes in anatomical parameters by histochemistry and microscopy, quantitative and qualitative changes in suberin composition by analytical chemistry, transcript changes by RNA-sequencing (RNA-Seq), and the radial water and solute movement of roots using a root pressure probe. In response to osmotic stress, genes in the suberin biosynthesis pathway were upregulated that correlated with increased suberin amounts in the endodermis and an overall reduction in hydraulic conductivity (Lpr ). In parallel, transcriptomic data indicated no or only weak effects of osmotic stress on aquaporin expression. These results indicate that osmotic stress enhances cell wall suberization and markedly reduces Lpr of the apoplastic pathway, whereas Lpr of the cell-to-cell pathway is not altered. Thus, the sealed apoplast markedly reduces the uncontrolled backflow of water from the root to the medium, whilst keeping constant water flow through the highly regulated cell-to-cell path.

Journal ArticleDOI
Yupeng Liu1, Youbin Zheng1, Tinghua Li, Daoai Wang1, Feng Zhou1 
TL;DR: In this article, a repairable water-solid triboelectric nanogenerator (W-TENG) based on superhydrophobic surface is fabricated to harvest water-flow energy.

Journal ArticleDOI
TL;DR: In this article, the response of the complex system of gas hydrate accumulations at Site NGHP-02-09, Krishna-Godavari Basin, Indian Ocean, to different production conditions, and to determine the technical feasibility of gas production through depressurization-induced dissociation was quantified by means of numerical simulation.

Journal ArticleDOI
TL;DR: In this article, a series of water flow tests through both intact and fractured samples were conducted in a triaxial cell under different confining pressures (10-30 MPa) and varying inlet hydraulic pressures (0.4-6 MPa).
Abstract: This study focuses on the transport properties and permeability evolution characteristics of fluid flow through thermally treated rock samples containing single fractures. First, splitting fractures were generated in cylindrical granite samples after high-temperature exposure (25–800 °C). Then a series of water flow tests through both intact and fractured samples were conducted in a triaxial cell under different confining pressures (10–30 MPa) and varying inlet hydraulic pressures (0.4–6 MPa). The results show that as the temperature increases from 25 to 800 °C, the standard deviations of the 3D spatial distribution parameters, including the asperity height, slope angle, and aspect direction of the fracture surface mesh element planes, all increase, indicating gradually increasing fracture surface roughness. The relationships between the pressure gradient and flow rate of intact samples, fractured rock samples, and the fractures themselves can all be well fitted using the Forchheimer’s law. Both linear and nonlinear coefficients in the Forchheimer’s law increase with increasing confining pressure. An exponential function is used to evaluate the equivalent permeability of intact samples based on temperature levels. The permeability undergoes an increasing trend as the temperature increases due to thermally induced defects, but undergoes a decreasing trend as the confining pressure increases due to defect closure. Two representative types of flow characteristics through the fractured rock samples, dominated by either the rock matrix or fracture flow, are identified. In the temperature range of 25–800 °C, the critical Reynolds number of the fractures declines, which first remains generally constant for temperatures of 25–400 °C and then experiences a dramatic decrease for temperatures of 400–800 °C. The nonlinear coefficient bf in Forchheimer’s law versus the hydraulic aperture eh curves displays a decreasing trend following a power-law relationship. The Forchheimer’s law results are evaluated by plotting the normalized transmissivity against the pressure gradient. An increase in the confining pressure shifts the fitted curves downward. As the temperature increases, the contribution of the matrix to the overall discharge capacity of the fractured rock samples gradually enhances, while that for the fractures weakens. The reduction extent in permeability of the rough-walled fractures is more remarkable than that of the matrix under an applied confining pressure.

Journal ArticleDOI
TL;DR: In this paper, the authors used a wide grain size distribution with unconsolidated dam material to estimate the outflow hydrograph and the resulting inundation of a landslide dam that is breached due to overtopping failure.