Direction Of Water Flow Research Articles

Breaking All the Rules: The First Recorded Hard Substrate Sessile Benthic Community Far Beneath an Antarctic Ice Shelf

The seafloor beneath floating ice shelves accounts roughly a third of the Antarctic’s 5 million km2 of continental shelf. Prior to this study, our knowledge of these habitats and the life they support was restricted to what has been observed from eight boreholes drilled for geological and glaciological studies. The established theory of sub-ice shelf biogeography is that both functional and taxonomic diversities decrease along a nutrient gradient with distance from the ice shelf front, resulting in a depauperate fauna, dominated by mobile scavengers and predators toward the grounding line. Mobile macro-benthic life and mega-benthic life have been observed as far as 700 km under an ice shelf. New observations from two boreholes in the Filchner-Ronne Ice Shelf challenge the idea that sessile organisms reduce in prevalence the further under the ice you go. The discovery of an established community consisting of only sessile, probably filter feeding, organisms (sponges and other taxa) on a boulder 260 km from the ice front raises significant questions, especially when the local currents suggest that this community is somewhere between 625 km and 1500 km in the direction of water flow from the nearest region of photosynthesis. This new evidence requires us to rethink our ideas with regard to the diversity of community types found under ice shelves, the key factors which control their distribution and their vulnerability to environmental change and ice shelf collapse.

A neuronal blueprint for directional mechanosensation in larval zebrafish

Animals have a remarkable ability to use local cues to orient in space in the absence of a panoramic fixed reference frame. Here we use the mechanosensory lateral line in larval zebrafish to understand rheotaxis, an innate oriented swimming evoked by water currents. We generated a comprehensive light-microscopy cell-resolution projectome of lateralis afferent neurons (LANs) and used clustering techniques for morphological classification. We find surprising structural constancy among LANs. Laser-mediated microlesions indicate that precise topographic mapping of lateral-line receptors is not essential for rheotaxis. Recording neuronal-activity during controlled mechanical stimulation of neuromasts reveals unequal representation of water-flow direction in the hindbrain. We explored potential circuit architectures constrained by anatomical and functional data to suggest a parsimonious model under which the integration of lateralized signals transmitted by direction-selective LANs underlies the encoding of water-flow direction in the brain. These data provide a new framework to understand how animals use local mechanical cues to orient in space.

Analysis on the effect of direct reading seal checking instrument in seal checking

The advantages and disadvantages of common sealing methods are analyzed. Aiming at the low sealing rate of bridge type eccentric distribution pipe string packer in Daqing Oilfield, this paper starts with the structure of bridge eccentric distribution pipe string and normal operation and water flow direction during sealing, and combines with the sealing section method sealing principle, discusses the main factors affecting the sealing efficiency of bridge eccentric distribution pipe string. The direct reading sealing tester produced by Xi’an Stan company is optimized. The working principle and sealing process of the sealing tester are analyzed. The switch operation of injection well is optimized. The research results show that: using the direct reading packer, combined with the off on off water injection operation, can verify the sealing performance of the bridge type eccentric distribution pipe string packer, the sealing effect is intuitive, and the test success rate is high.

ВОДНІ ДЖЕРЕЛА ВОЛИНСЬКОЇ ОБЛАСТІ: КЛАСИФІКАЦІЯ ТА ПРОСТОРОВЕ РОЗТАШУВАННЯ

The scientific interest in the study of water sources is related to their recreational, environmental and sacred significance, as well as the prospect of use in the drinking water supply. The object of this study is the natural water springs of the Volyn region. The methodological basis is a combination of geographical and environmental approaches used in the investigation of the interaction of man and nature. The scientific novelty of the research is the application of a scientific approach to the study of water springs in the Volyn region not only as factors in maintaining water balance but also as objects of worship. The study of geological and hydrogeological preconditions for the formation of water springs in the Volyn region shows that the groundwater of the study area belongs to the bicarbonate class, a group of calcium mainly of the first or second type. The existing classifications of water springs are generalized and adapted to the conditions of Volyn region. The classification of water springs is made on the following features: the direction of water flow, the peculiarity of functioning, the nature of use, hydrological conditions, chemical composition and the level of sacredness. According to the results of the study, it was established that within the study area there were 81 functioning springs, 52 of which are consecrated. The spatial location of water springs in the Volyn region has been studied in the structure of physical and geographical areas. It is established that the largest share of them was formed in Verkhnoprypiatskyi (19), Liubomlsko-Kovelskyi (18) and Turiisko-Rozhyshchenskyi (15) physical-geographical districts. Some consecrated water springs of the Volyn region, which are used as objects of worship, are described, in particular in the villages: Telchi, Vorotniv, Hirka Polonka, Hremiache, Sokil. The widespread disappearance of natural water springs in the Volyn region is due to the natural and anthropogenic factors and is associated not only with their pollution, siltation, drying but also with the depletion of groundwater. In order to preserve and reproduce water springs, we advise continuing to work on their arrangement, to intensify the organization of operational and long-term forecasts of environmental change, monitoring of chemical and biological pollution, certification, and creation of protected areas within them.

Stable and Anisotropic Freezing Framework With Interaction Between IISPH Fluids and Ice Particles

In this paper, we present a novel method that can stably express the directional ice form caused by freezing of flowing water. The key to the proposed framework is to reflect the flow of fluids with viscosity in the direction of ice growth. Water is simulated by applying a new viscous technique to the implicit incompressible fluid simulation, and the proposed anisotropic freezing solution is used to express directional ice and glaze effects. The conditions under which water particles turn into ice particles are calculated according to a new energy function based on humidity and water flow. The humidity is approximated based on the virtual water film on the surface of the object, and the flow of fluid is incorporated into our anisotropic freezing solution to guide the growth direction of the ice. As a result, the proposed technique reliably produces glaze and directional freezing effects according to the flow direction of viscous water.

Performance evaluation of flow routing algorithms in different topographic characteristics

It is a complicated process to estimate the direction of water flow above the Earth's surface. Several algorithms exist to calculate the flow direction, which may yield different results for a particular place with specific topographic characteristics. The complicacy lies in the choice of algorithm to get more accurate results. The selection of algorithms should be made considering their suitability in different topographic situations. In this research, eight existing commonly used algorithms have been used to extract the streamlines of a study area with a distinct topographic condition. This study tends to analyse and compare the resulted streamlines from these algorithms with a reference streamline. Evaluation has been done based on variation in stream orders, variation in contributing cells and spatial changes. Spatial differences have also been measured considering three topographic characteristics: elevation, slope, and roughness of study areas. Lastly, this study attempts to suggest the usability of these algorithms in different terrain characteristics.

Multi-stage decision-making method for ship speed optimisation considering inland navigational environment

Speed optimisation is an important energy efficiency practice, which can bring good economic and environmental benefits. The methodology of the speed optimisation and dynamic programming of ships are firstly investigated. With the total fuel consumption as the objective function and main engine speed as the decision variable, a novel multi-stage speed optimisation model of ship is then developed based on dynamic programming algorithm. A Yangtze river ship is selected as a case study, the actual operational data are acquired through sensors installed onboard the ship. Using the operational data, regression analysis is applied to establish the relationship models of ship fuel consumption and speed in relative to main engine speed. Finally, simulating calculation and comparative analyses are carried out. The results indicate that the velocity and direction of water flow is a key factor affecting the speed optimisation of ships in the Yangtze river; the proposed multi-stage decision making method is effective in the speed optimisation for ship with a long-distance and changing-environment voyage. This study can provide methodological support for ship navigational optimisation.

Tracer test on the Dragonja landfill

The paper presents the results of a tracer experiment with the uranine tracer at the non-hazardous landfill of Dragonja. The purpose of the tracer test was to determine the dynamics of the potential pollutants from the landfill to the groundwater. The landfill lies on the thicker weathered layer of flysch rock that forms the slope of the hill. At the foot of the hill are silty clay and partly sandy alluvial sediments of the Dragonja River. The transport of uranine depends on the intensity and duration of precipitation, potential evapotranspiration, permeability, precipitation infiltration into the landfill, and saturation of the weathering layer of flysh. Uranine first appeared in the observation well P2, which is located downstream of the injection point, in the direction of water flow. Observation well P1 is not in the direction of direct flow and therefore only the edge of the dispersed tracer plume appeared in P1. The groundwater from the flysch weathered layer drains into the alluvial plain and the uranine concentrations are diluted in the groundwater. In the observation well P5 a slow increase and decrease of the uranium concentration was therefore observed. Due to the high evapotranspiration, the groundwater levels were falling until October, when they began to rise after autumnal precipitation events. The tracer experiment confirmed the heterogeneity and complexity of the geological structure of the landfill site.

Study on the natural gas diffusion behavior in sewage pipeline by a new outdoor full-scale water cycling experimental pipeline system

To initiate the experimental study of natural gas diffusion in sewage pipeline and evaluate the sewage pipeline risk, a new outdoor full-scale water cycling experimental pipeline system was built. The concentration distributions and characteristic time were measured in a comprehensive monitoring system. As the rate of the gas leakage flow decreases, the alarm time increases significantly. It is found that the influence of water flow direction on methane gas diffusion is different under varying gas flow rates. Furthermore, the methane diffusion rate in sewage pipeline is also a function of water flow rate and water level height. Based on the experimental results, the corresponding suggestions for prevention and control of gas leakage accidents in sewage pipelines were put forward to improve the urban public security management system and the security capacity of urban public security.

A Hidden Markov Tree Model for Flood Extent Mapping in Heavily Vegetated Areas based on High Resolution Aerial Imagery and DEM: A Case Study on Hurricane Matthew Floods

ABSTRACT Flood extent mapping plays a crucial role in disaster management and national water forecasting. In recent years, high-resolution optical imagery becomes increasingly available with the deployment of numerous small satellites and drones. However, analysing such imagery data to extract flood extent poses unique challenges due to the rich noise and shadows, obstacles (e.g. tree canopies, clouds), and spectral confusion between pixel classes (flood, dry) due to spatial heterogeneity. Existing machine-learning techniques often focus on spectral and spatial features from raster images without fully incorporating the geographic terrain within classification models. In contrast, we recently proposed a novel machine-learning model called geographical hidden Markov tree (HMT) that integrates spectral features of pixels and topographic constraint from Digital Elevation Model (DEM) data (i.e. water flow directions) in a holistic manner. This paper evaluates the model through case studies on high-resolution aerial imagery from National Oceanic and Atmospheric Administration (NOAA) National Geodetic Survey (NGS) together with DEM. Three scenes are selected in heavily vegetated floodplains near the cities of Grimesland and Kinston in North Carolina during Hurricane Matthew floods in 2016. Results show that the proposed HMT model outperforms several state of the art machine-learning algorithms (e.g. random forests, gradient-boosted model) by an improvement of F-score (the harmonic mean of the user’s accuracy and producer’s accuracy) from around 70% to 80% to over 95% on our datasets.

안정적이고 이방성한 빙결 모델링을위한 암시적 비압축성 유체와 얼음 입자간의 상호작용 기법

In this paper, we propose a new method to stable simulation the directional ice shape by coupling of freezing solver and viscous water flow. The proposed ice modeling framework considers viscous fluid flow in the direction of ice growth, which is important in freezing simulation. The water simulation solution uses the method of applying a new viscous technique to the IISPH(Implicit incompressible SPH) simulation, and the ice direction and the glaze effect use the proposed anisotropic freezing solution. The condition in which water particles change state to ice particles is calculated as a function of humidity and new energy with water flow. Humidity approximates a virtual water film on the surface of the object, and fluid flow is incorporated into our anisotropic freezing solution to guide the growth direction of ice. As a result, the results of the glaze and directional freezing simulations are shown stably according to the flow direction of viscous water.

Enhanced performance of piezoelectric energy harvester through three serial vibrators

This paper presents a piezoelectric harvester array with three identical energy harvesting vibrators (EHVs) arranged in series along the water flow direction. Each EHV consists of a piezoelectric beam and an interference cylinder. Three serial EHVs are placed upright in the water channel. Prototypes of three EHVs are fabricated and experiments are conducted to explore the vibration response and harvesting performance. The experimental results demonstrated that three EHVs in the array show the obvious difference in excitation vibration and harvesting performance over single EHV. The lock-in frequency of three EHVs can be enhanced by the EHV array, and the speed bandwidth can be greatly broadened by accounting for 66.9%. The harvesting performance of upstream EHV (EHV-1) and downstream EHV (EHV-3) is significantly improved by the EHV array over single EHV. While, midstream EHV (EHV-2) shows an inhibitory effect to some extent. The overall harvesting performance in the EHV array can be increased by up to 36.23% compared with single EHV in certain spacing distances. The proposed EHV array shows the better harvesting ability over the previous harvesters. This work provides a comprehensive experimental guideline for further designing efficient harvester array used in low-speed water environment.

Simultaneous fluid and solid density measurements in swelling clay using X‐ray microtomography and 3D particle tracking

AbstractIn order to demonstrate the safety of engineered barriers for radwaste geological repositories, rich characterisations of bentonite hydro‐mechanical behaviour are essential. X‐ray computed tomography was used as the single input to measure both the full displacement field and water content in a heterogeneous bentonite sample resaturated in quasi‐isochoric conditions. Since large texture changes do not allow the use of digital volume correlation, this was achieved using 3D particle tracking to provide the kinematics in combination with calibrated and beam hardening‐corrected grey levels. Matching the grey level sampling with kinematics using a mesh‐based analysis, results show the development of heterogeneous swelling inside the cell and a final solid density gradient in the direction of water flow.

Hydrogeological control on the accumulation and production of coalbed methane in the Anze Block, southern Qinshui Basin, China

This study of geological and hydrogeological conditions in the coal-bearing Shanxi and Taiyuan formations in the Anze Block, southern Qinshui Basin, reveals the water-flow direction, hydrodynamic units, special tectonic units and their influence on the accumulation and production of coalbed methane. Water composition variation, hydrogen and oxygen isotopes, and total dissolved solids were used to analyze the type and source of the co-produced water, the connection between the coalbed methane wells and aquifers, the flow direction of groundwater, and to characterize water-rock interactions. Coal seam No. 3 in the Shanxi Formation is less affected by external water, while coal seam No. 15 in the Taiyuan Formation has a hydraulic connection with the roof K2 limestone aquifers. Due to the differences in the hydrodynamic units, structural uplift, and faults, the gas content of coal seam No. 15 is higher than that of coal seam No. 3. Hydrostratigraphic cross sections were built to characterize the coalbed methane accumulation in coal seams No. 3 and No. 15. The hydrodynamic units and the water-conducting faults or collapse columns are the main factors affecting the gas content, and gas and water production rates in the Anze Block.

Low light intensities increase avoidance behaviour of diurnal fish species: implications for use of road culverts by fish.

Inadequately designed culverts can be physical barriers to fish passage if they increase the velocity of water flow in the environment, alter natural turbulence patterns or fail to provide adequate water depth. They may also act as behavioural barriers to fish passage if they affect the willingness of fish species to enter or pass through the structure due to altered ambient light conditions. To understand how reduced light intensity might affect fish behaviour in culverts, the authors performed a behavioural choice experiment quantifying the amount of time individual fish spent in dark and illuminated areas of a controlled experimental channel. They found that behavioural responses were largely reflective of the species' diel activity patterns; the diurnal species Craterocephalus stercusmuscarum and Retropinna semoni preferred illuminated regions, whereas the nocturnal/crepuscular Macquaria novemaculeata preferred the darkened region of the channel. Bidyanus bidyanus were strongly rheotactic, and their behaviour was influenced more by water flow direction than ambient light level. The authors then determined that a threshold light intensity of only c. 100-200 lx (cf. midday sunlight c. 100,000 lx) was required to overcome the behavioural barrier in c. 70% of the diurnally active C. stercusmuscarum and R. semoni tested. When these values were placed into an environmental context, 15 road-crossing (3.4-7.0 m long) box (c. 1 m × 1 m, height × width) and pipe (c. 1 m diameter) culverts sampled in Brisbane, Australia, recorded light intensities in the centre of the structure that were below the threshold for C. stercusmuscarum and R. semoni movement and could potentially be a barrier to their passage through the structure. Attention is required to better understand the impacts of low light intensity in culverts on fish passage and to prioritize restoration.

Performance of different types of constructed wetlands for treating wastewater in short time horizon

Constructed wetland is one of the well-knowncost-effective technologies for treating domestic sewage. This work is mainly focuses to study the performance of constructed wetland at initial stage of wetland. Three types of constructed wetland namely Vertical Flow Constructed Wetland (VFCW), Horizontal zigzag flow Constructed wetland (HFCW) and Upflow Constructed Wetland (UFCW) were made based upon the direction of water flow through porous medium. The primary treated sewage is passed through three wetlands and the water quality was tested before and after treatment. Wetland performance was analyzed continuously for one month after sapling stage. Water quality parameters such as pH, Temperature Total Suspended Solids (TSS), Total Dissolved Solids (TDS), Chemical Oxygen Demand (COD), Nitrates (NO3 -) and Phosphate (PO4 -) were tested. Removal of COD and Phosphates are uniformly increasing for this duration. The maximum removal of COD, TSS and Phosphates are 40%, 30%, 87% and 45% respectively. Nitrification is good from initial stage of constructed wetland. In one month experimental period, removal of solids is not stable. It was observed that, heavy fluctuation was occurred during experimental period. But increasing trend is observed in the removal of solids. Also it is recommended that more sampling is needed at initial stage of constructed wetlands.

Transcapillary transport of water, small solutes and proteins during hemodialysis

The semipermeable capillary walls not only enable the removal of excess body water and solutes during hemodialysis (HD) but also provide an essential mechanism for maintaining cardiovascular homeostasis. Here, we investigated transcapillary transport processes on the whole-body level using the three-pore model of the capillary endothelium with large, small and ultrasmall pores. The transcapillary transport and cardiovascular response to a 4-h hemodialysis (HD) with 2 L ultrafiltration were analyzed by simulations in a virtual patient using the three-pore model of the capillary wall integrated in the whole-body compartmental model of the cardiovascular system with baroreflex mechanisms. The three-pore model revealed substantial changes during HD in the magnitude and direction of transcapillary water flows through small and ultrasmall pores and associated changes in the transcapillary convective transport of proteins and small solutes. The fraction of total capillary hydraulic conductivity attributed to ultrasmall pores was found to play an important role in the transcapillary water transport during HD thus influencing the cardiovascular response to HD. The presented model provides a novel computational framework for a detailed analysis of microvascular exchange during HD and as such may contribute to a better understanding of dialysis-induced changes in blood volume and blood pressure.

SELF-POTENTIAL METHOD FOR DETECTION OF WATER LEAKAGE THROUGH DAMS

The self-potential (SP) method is a passive, non-invasive and cost-effective geophysical method based on the measurement of electrical potential naturally occurring on the earth’s surface. One of the main causes for the electrical potential at the earth’s surface is water seepage under the ground. In this work, we perform the SP measurement on a small artificial earthen dam built at Thuyloi University. Our result shows that the selection of electrode types is crucial in the SP measurements. Namely, Cu/CuSO4 porous pots are much better than copper stake electrodes for the SP measurement. Additionally, it is shown that the SP measurement using suitable electrodes can be applied to detect underground water leakage and flow direction in the dam based on an anomaly and variation of electric potential with position on the survey area.

Impact effects due to hot vapour bubble collapse in subcooled liquid

Collapse of a hot vapour bubble captured by subcooled water can produce a cumulative jet similar to that appearing in cavitating flows. In the context of stratified steam explosions following spreading of hot melt under a water layer, impact of the water jets can be a reason for melt splashes promoting the mixing of cold and hot liquids necessary for energetic interaction. In this work, the characteristics of the directional water flow caused by collapse of a bubble near a wall are obtained, and a correlation is given which relates the ultimate height of melt rise to the bubble parameters and droplet size. Estimates relevant to melt splashes caused by the cumulative water jet impact are presented which agree with the experimental observations available in the literature.

Effective hydraulic conductivity of stony soils: General effective medium theory

Despite a longstanding interest in understanding the effects of rock fragments on soil hydraulic properties, physically-based models to describe the effective hydraulic conductivity of stony soils are still rare. The conductivity of stony soils is mostly described by simple scaling approaches, assuming impermeable rock fragments. We present a model based on the general effective medium (GEM) theory to calculate the effective hydraulic conductivity of stony soils. The model accounts for the volumetric content, shape, and orientation of rock fragments in the main direction of water flow. Rock fragments can either be permeable or impermeable in the model which allows to calculate the effective unsaturated hydraulic conductivity curve of stony soils over the full range of soil matric potentials. Existing models assume rock fragments to be isolated and their application is therefore limited to low to moderately stony soils. In GEM model interaction between rock fragments is allowed, which makes it applicable in stony soils with high contents of rock fragments. The mathematical simplicity of the model makes it suitable for practical applications and provides a strong theoretical basis for improving predictions of flow and transport in hydrological models applied in forested and agricultural watersheds and mountainous areas.