Showing papers on "Water flow published in 2021"

Glacial change and hydrological implications in the Himalaya and Karakoram

Abstract: Glaciers in the Himalaya–Karakoram mountain ranges harbour approximately half of the ice volume in High-mountain Asia and modulate the flow of freshwater to almost 869 million people within the Indus, Tarim, Ganges and Brahmaputra river basins Since the mid-twentieth century, rising temperatures have led to unsustainably high melting rates for many glaciers, particularly in the Himalaya, temporarily increasing summer meltwater run-off but continuously reducing the ice-storage volume In this Review, we discuss how and why glaciers and meltwater supplies have changed, how they will likely evolve in the future and how these changes impact water resources and water-related hazards Heterogeneous glacier retreat is changing streamflow patterns, in turn, affecting the incidence of glacial-lake outburst floods and exacerbating the risk of flooding and water shortages associated with future climate change These changes could negatively impact downstream populations and infrastructure, including the thriving hydropower sector and some of the world’s largest irrigated agriculture systems, by making water flow more extreme and unpredictable An improved in situ monitoring network for weather, hydrology and glacier change is a crucial requirement for predicting the future of this resource and associated hazards, and their impact on regional water, energy and food security Glaciers in the Himalaya and Karakoram mountain ranges provide freshwater and hydropower to millions of people but are also melting at unsustainably high rates This Review discusses recent and projected changes in glacier melt and resulting implications for regional water-related hazards and water resources

Molecular mechanisms of brain water transport.

Abstract: Our brains consist of 80% water, which is continuously shifted between different compartments and cell types during physiological and pathophysiological processes. Disturbances in brain water homeostasis occur with pathologies such as brain oedema and hydrocephalus, in which fluid accumulation leads to elevated intracranial pressure. Targeted pharmacological treatments do not exist for these conditions owing to our incomplete understanding of the molecular mechanisms governing brain water transport. Historically, the transmembrane movement of brain water was assumed to occur as passive movement of water along the osmotic gradient, greatly accelerated by water channels termed aquaporins. Although aquaporins govern the majority of fluid handling in the kidney, they do not suffice to explain the overall brain water movement: either they are not present in the membranes across which water flows or they appear not to be required for the observed flow of water. Notably, brain fluid can be secreted against an osmotic gradient, suggesting that conventional osmotic water flow may not describe all transmembrane fluid transport in the brain. The cotransport of water is an unconventional molecular mechanism that is introduced in this Review as a missing link to bridge the gap in our understanding of cellular and barrier brain water transport.

The Role of Plant Growth-Promoting Bacteria in Alleviating the Adverse Effects of Drought on Plants

Abstract: Plant growth-promoting bacteria play an essential role in enhancing the physical, chemical and biological characters of soils by facilitating nutrient uptake and water flow, especially under abiotic stress conditions, which are major constrains to agricultural development and production. Drought is one of the most harmful abiotic stress and perhaps the most severe problem facing agricultural sustainability, leading to a severe shortage in crop productivity. Drought affects plant growth by causing hormonal and membrane stability perturbations, nutrient imbalance and physiological disorders. Furthermore, drought causes a remarkable decrease in leaf numbers, relative water content, sugar yield, root yield, chlorophyll a and b and ascorbic acid concentrations. However, the concentrations of total phenolic compounds, electrolyte leakage, lipid peroxidation, amounts of proline, and reactive oxygen species are considerably increased because of drought stress. This negative impact of drought can be eliminated by using plant growth-promoting bacteria (PGPB). Under drought conditions, application of PGPB can improve plant growth by adjusting hormonal balance, maintaining nutrient status and producing plant growth regulators. This role of PGPB positively affects physiological and biochemical characteristics, resulting in increased leaf numbers, sugar yield, relative water content, amounts of photosynthetic pigments and ascorbic acid. Conversely, lipid peroxidation, electrolyte leakage and amounts of proline, total phenolic compounds and reactive oxygen species are decreased under drought in the presence of PGPB. The current review gives an overview on the impact of drought on plants and the pivotal role of PGPB in mitigating the negative effects of drought by enhancing antioxidant defense systems and increasing plant growth and yield to improve sustainable agriculture.

Emerging roles for dynamic aquaporin-4 subcellular relocalization in CNS water homeostasis.

Abstract: Aquaporin channels facilitate bidirectional water flow in all cells and tissues. AQP4 is highly expressed in astrocytes. In the CNS, it is enriched in astrocyte endfeet, at synapses, and at the glia limitans, where it mediates water exchange across the blood-spinal cord and blood-brain barriers (BSCB/BBB), and controls cell volume, extracellular space volume, and astrocyte migration. Perivascular enrichment of AQP4 at the BSCB/BBB suggests a role in glymphatic function. Recently, we have demonstrated that AQP4 localization is also dynamically regulated at the subcellular level, affecting membrane water permeability. Ageing, cerebrovascular disease, traumatic CNS injury, and sleep disruption are established and emerging risk factors in developing neurodegeneration, and in animal models of each, impairment of glymphatic function is associated with changes in perivascular AQP4 localization. CNS oedema is caused by passive water influx through AQP4 in response to osmotic imbalances. We have demonstrated that reducing dynamic relocalization of AQP4 to the BSCB/BBB reduces CNS oedema, and accelerates functional recovery in rodent models. Given the difficulties in developing pore-blocking AQP4 inhibitors, targeting AQP4 subcellular localization opens up new treatment avenues for CNS oedema, neurovascular and neurodegenerative diseases, and provides a framework to address fundamental questions about water homeostasis in health and disease.

Piezoelectric activation of peroxymonosulfate by MoS2 nanoflowers for the enhanced degradation of aqueous organic pollutants

Abstract: Natural mechanical energies, such as wind, tidal waves, and water flow, widely exist in the environment and these inexhaustible natural mechanical energies can be utilized through piezoelectric materials for the degradation of aqueous organic pollutants in the environment In this work, few-layered molybdenum disulfide nanoflowers (MoS2 NFs) were adopted as a piezocatalyst to activate peroxymonosulfate (PMS) with ultrasonic waves (US) as the mechanical force for phenol abatement A much higher degradation efficiency was attained by the integrated US/MoS2 NFs/PMS system compared to other single systems, revealing the markedly synergistic effect of US and MoS2 on PMS activation Moreover, density functional theory calculations were performed to fundamentally understand the charge distribution in a polarized MoS2 nanosheet under different strains and to understand the piezocatalytic properties of MoS2 nanosheets, as well as reaction pathways between PMS and carriers on the active edges of MoS2 for the production of free radicals It was found that both sulfate radicals (SO4˙−) and hydroxyl radicals (˙OH) were produced in the US/MoS2 NFs/PMS system However, SO4˙− was quickly converted into ˙OH via a hydrolysis reaction under US, enabling ˙OH to be the primary reactive oxygen species for phenol oxidation This work offers an efficient piezocatalyst to activate persulfate for water remediation More importantly, it provides fundamental insights into the piezoelectricity in two-dimensional semiconducting materials and the mechanism in the piezocatalytic activation of persulfate Results prove that the combination of piezoelectricity and advanced oxidation processes is promising for water pollution control, and provides a new idea for the application of inexhaustible natural mechanical energy in the environment for environmental remediation

Fluctuation-induced quantum friction in nanoscale water flows

Abstract: The peculiar flow of water in carbon nanochannels has defied understanding thus far, with accumulating experimental evidence for ultra-low friction, exceptionally high water flow rates, and curvature-dependent hydrodynamic slippage. These unique properties have raised considerable interest in carbon-based membranes for desalination, molecular sieving and energy harvesting. However, the underlying mechanism for the bizarre water-carbon friction remains a critical knowledge gap, with neither current theories, nor classical or ab initio molecular dynamics simulations providing satisfactory rationalisation for this singular behaviour. Here, we develop a quantum microscopic theory of the solid-liquid interface, which explicitly takes into account the electronic degrees of freedom of the solid through a non-equilibrium field theory framework. Our theory reveals a new contribution to friction, which is due to the coupling of charge fluctuations in the liquid to electronic excitations in the solid. We expect that this quantum friction, which cannot be accounted for by Born-Oppenheimer molecular dynamics, is the dominant friction mechanism for water on carbon-based materials. As a key result, we demonstrate a dramatic difference in quantum friction between the water-graphene and water-graphite interface, due to the coupling of water Debye collective modes with a thermally excited, low energy interlayer plasmon specific to graphite. This suggests an explanation for the radius-dependent slippage of water in carbon nanotubes, in terms of the nanotubes' surface electronic excitations. Our findings open the way to quantum engineering of hydrodynamic flows through the confining wall electronic properties.

Phase change materials in solar domestic hot water systems: A review

Abstract: In this work, technologies related to the storage of solar energy, utilizing the latent heat content of phase change materials for the production of domestic hot water are reviewed. Many researchers have been involved in this field in order to accomplish the targets of environmentally friendly solutions and higher efficiency. For domestic use, materials with melting temperature between 40 and 80 °C are commonly studied, with paraffins, fatty acids, salt hydrates and alcohols being the most popular. For harvesting the solar radiation, usually flat plate or evacuated tubes solar collectors are used, either commercial ones or modified. The storage unit may include only phase change material or it can have a hybrid form combined with water. The outcome of the most studies, is that the addition of phase change materials in comparison to systems without latent storage, increases the duration of heat release towards the domestic water at the end of the day and also increases the solar collector's efficiency because it does not experience large temperature fluctuations. However, difficulties emerge during the selection of the appropriate storage material as this must have a high melting temperature in order to provide hot enough domestic water, but not higher than the temperature that the solar collector can produce, in order to fully melt the material. Moreover, investigation is necessary for the selection of the optimum water flow rate that minimizes the charging duration and maximizes the system efficiency and hot water amount. Another challenge that researchers face is the low thermal conductivity of many phase change materials. For this purpose, methods for improving the performance of the systems have been examined and they are also reported.

Modeling and Analysis of Heat Dissipation for Liquid Cooling Lithium-Ion Batteries

Abstract: To ensure optimum working conditions for lithium-ion batteries, a numerical study is carried out for three-dimensional temperature distribution of a battery liquid cooling system in this work. The effect of channel size and inlet boundary conditions are evaluated on the temperature field of the battery modules. Based on the thermal behavior of discharging battery obtained experimental measurements, two temperature control strategies are proposed and studied. The results show that the channel width of the cooling plates has a great influence on the maximum temperature in the battery module. It is also revealed that increasing inlet water flow rate can significantly improve the heat transfer capacity of the battery thermal management system, while the relationship between them is not proportional. Lowering the inlet temperature can reduce the maximum temperature predicted in the battery module significantly. However, this will also lead to additional energy consumed by the cooling system. It is also found that the Scheme 5 among various temperature control strategies can ensure the battery pack working in the best temperature range in different depths of discharge. Compared with the traditional one with a given flow rate, the parasitic energy consumption in Scheme 5 can be reduced by around 80%.

The energy-food-water nexus: Water footprint of Henan-Hubei-Hunan in China

Abstract: Energy security, food security, and water security have become the three most prominent problems in human survival and sustainable development. The three are interrelated and directly affect each other; that is, there exists a nexus between, energy, food, and water (EFW). A scientific understanding and correct response to this is important for achieving the sustainable development of natural resources. This study uses quantitative analysis to estimate the Central China region's energy-food production water footprint (WF) and virtual trade water flow from 2001 to 2016. It proposes a Modified Water Stress Index (MWSI) associated with virtual water outflows and evaluates the pressure exerted by virtual water flowing out, along with the effect of trade on local water resources systems. The results indicate that the energy and food production WF and virtual trade water flow are on the rise, causing water stress in local and export areas. Based on the adjustment of industrial structure, optimization of production technology, and rational regionalization of ecological divisions, the paper makes comprehensive policy recommendations to ensure the region's sustainable development of water resources for the future.

Heat dissipation optimization for a serpentine liquid cooling battery thermal management system: An application of surrogate assisted approach

Abstract: Lithium-ion batteries are currently the primary source of power for electric vehicles (EVs), but the batteries are sensitive to temperature changes. Excessively high or low temperatures will affect the batteries performance, causing thermal runaway and safety accidents. The battery thermal management system (BTMS) can maintain the batteries within a safe temperature range. This paper studied a liquid cooling BTMS incorporating serpentine microchannels. Firstly, we studied the arrangement of the inlet direction of serpentine microchannel cooling plates. The research demonstrated that for plan 3 (i.e., inlet and outlet are staggered), the BTMS has the best cooling performance. The maximum temperature of plan 3 is 311.2592 K, which is 0.6892 K lower than plan 1. Then, we selected plan 3 as the baseline. The surrogate assisted approach was conducted to parameterize and model the selected scheme. After that, the multi-objective genetic algorithm (MOGA) was used to optimize the parameters of the serpentine channel and water flow velocity. The optimization results indicated that the maximum temperature of the battery module dropped from 311.2592 K to 308.6067 K, the maximum pressure decreased from 578.9111 Pa to 502.0554 Pa, the average temperature decreased from 308.7952 K to 306.0020 K. After optimization, the temperature uniformity of the battery module is significantly improved, which provides guidance for improving the heat dissipation performance of the serpentine liquid cooling BTMS. Especially, the maximum pressure decreased by 13.28%, which can reduce the pumping power of the cooling water in the channel, and the consumption of energy of the EVs.

New Insights into the Microplastic Enrichment in the Blue Carbon Ecosystem: Evidence from Seagrass Meadows and Mangrove Forests in Coastal South China Sea

Abstract: Microplastics were recently found to aggregate in the blue carbon ecosystems (BCEs), which are known for their ability to store carbon by slowing down the water flow. However, evidence is largely lacking on how the accumulation of microplastics is related to carbon sequestration in BCEs and if this trap effect is driven by its biological characteristics. In this study, the trap effect of microplastics by BCEs was evaluated for various seagrasses (Zostera japonica, Halophila ovalis, and Halophila beccarii) and mangroves (Aegiceras corniculatum and Avicennia marina). Significant accumulation was found in the seagrass meadow dominated by H. beccarii and the mangrove forest dominated by A. marina, with microplastics enriched by 1.3 to 17.6 times compared to their corresponding unvegetated sites. The abundance of microplastics varied greatly from 17.68 ± 8.10 to 611.75 ± 81.52 particles per kg of dry sediment, with the highest abundance in A. marina mangrove sediments. A strong positive correlation was found between the abundance of microplastics and the particulate organic carbon content at all study sites (Pearson, R = 0.86, p < 0.01). Higher diversity of microplastic colors and size was found in the H. beccarii meadow, and higher diversity of shapes was found in the A. marina forest. Our results added new insights to the understanding of the mechanism of microplastic trapping by BCEs and coupled the behavior of microplastics with the organic carbon in the sediment.

Detecting forest response to droughts with global observations of vegetation water content.

Abstract: Droughts in a warming climate have become more common and more extreme, making understanding forest responses to water stress increasingly pressing. Analysis of water stress in trees has long focused on water potential in xylem and leaves, which influences stomatal closure and water flow through the soil-plant-atmosphere continuum. At the same time, changes of vegetation water content (VWC) are linked to a range of tree responses, including fluxes of water and carbon, mortality, flammability, and more. Unlike water potential, which requires demanding in situ measurements, VWC can be retrieved from remote sensing measurements, particularly at microwave frequencies using radar and radiometry. Here, we highlight key frontiers through which VWC has the potential to significantly increase our understanding of forest responses to water stress. To validate remote sensing observations of VWC at landscape scale and to better relate them to data assimilation model parameters, we introduce an ecosystem-scale analog of the pressure-volume curve, the non-linear relationship between average leaf or branch water potential and water content commonly used in plant hydraulics. The sources of variability in these ecosystem-scale pressure-volume curves and their relationship to forest response to water stress are discussed. We further show to what extent diel, seasonal, and decadal dynamics of VWC reflect variations in different processes relating the tree response to water stress. VWC can also be used for inferring belowground conditions-which are difficult to impossible to observe directly. Lastly, we discuss how a dedicated geostationary spaceborne observational system for VWC, when combined with existing datasets, can capture diel and seasonal water dynamics to advance the science and applications of global forest vulnerability to future droughts.

6G-Enabled IoT Home Environment Control Using Fuzzy Rules

Abstract: Technological development increases capacity of information systems, which with development of faster data transfer will be able to host variety of new devices. In this article we present electronic modules, infrastructure and fuzzy rules control model with implemented software for new generation home environment. The system is developed for the next IoT level based on 6G network communication standards. Proposed control model is efficient in water flow management, wind shield control, security aspects and carbon dioxide limitation via adaptive ventilation. Developed infrastructure is ready for new 6G communication standard, which will additionally improve efficiency and data flow at end-user devices and local area level.

Drone Swarms in Fire Suppression Activities: A Conceptual Framework

Abstract: The recent huge technological development of unmanned aerial vehicles (UAVs) can provide breakthrough means of fighting wildland fires. We propose an innovative forest firefighting system based on the use of a swarm of hundreds of UAVs able to generate a continuous flow of extinguishing liquid on the fire front, simulating the effect of rain. Automatic battery replacement and extinguishing liquid refill ensure the continuity of the action. We illustrate the validity of the approach in Mediterranean scrub first computing the critical water flow rate according to the main factors involved in the evolution of a fire, then estimating the number of linear meters of active fire front that can be extinguished depending on the number of drones available and the amount of extinguishing fluid carried. A fire propagation cellular automata model is also employed to study the evolution of the fire. Simulation results suggest that the proposed system can provide the flow of water required to fight low-intensity and limited extent fires or to support current forest firefighting techniques.

Bioinspired Hierarchical Nanofabric Electrode for Silicon Hydrovoltaic Device with Record Power Output.

Abstract: Direct electricity generation from water flow/evaporation, coined hydrovoltaic effect, has recently attracted intense interest as a facile approach to harvest green energy from ubiquitous capillary water flow or evaporation. However, the current hydrovoltaic device is inferior in output power efficiency compared to other renewable energy devices. Slow water evaporation rate and inefficient charge collection at device electrodes are two fundamental drawbacks limiting energy output efficiency. Here, we report a bioinspired hierarchical porous fabric electrode that enables high water evaporation rate, efficient charge collection, and rapid charge transport in nanostructured silicon-based hydrovoltaic devices. Such an electrode can efficiently collect charges generated in nanostructured silicon as well as induce a prompt water evaporation rate. At room temperature, the device can generate an open-circuit voltage (Voc) of 550 mV and a short-current density (Jsc) of 22 μA·cm-2. It can output a power density over 10 μW·cm-2, which is 3 orders of magnitude larger than all those reported for analogous hydrovoltaic devices. Our results could supply an effective strategy for the development of high-performance hydrovoltaic devices through optimizing electrode structures.

The Effect of Activity, Energy Use, and Species Identity on Environmental DNA Shedding of Freshwater Fish

Abstract: The quantitative measurement of environmental DNA (eDNA) from field-collected water samples is gaining importance for the monitoring of fish communities and populations. The interpretation of these signal strengths depends, among other factors, on the amount of target eDNA shed into the water. However, shedding rates are presumably associated with species-specific traits such as physiology and behavior. Although such differences between juvenile and adult fish have been previously detected, the general impact of movement and energy use in a resting state on eDNA release into the surrounding water remains hardly addressed. In an aquarium experiment, we compared eDNA shedding between seven fish species occurring in European freshwaters. The investigated salmonids, cyprinids, and sculpin exhibit distinct adaptions to microhabitats, diets, and either solitary or schooling behavior. The fish were housed in aquaria with constant water flow and their activity was measured by snapshots taken every 30 s. Water samples for eDNA analysis were taken every 3 h and energy use was determined in an intermittent flow respirometer. After controlling for the effect of fish mass, our results demonstrate a positive correlation between target eDNA quantities as measured with digital PCR, fish activity, and energy use, as well as species-specific differences. For cyprinids, the model based on data from individual fish was only partly transferable to groups, which exhibited lower activity and higher energy use. Our findings highlight the importance of fish physiology and behavior for the comparative interpretation of taxon-specific eDNA quantities. Species traits should therefore be incorporated into eDNA-based monitoring and conservation efforts.