Delineation of wellhead protection zones: the analysis of main geological factors

Introduction. Analysis of the projects concerning wellhead protection (WHP) zones delineation shows the majority of the reports to use a simplified calculation. The applied analytical solutions do not refer to the actual geological conditions of the operating water intakes. The lack of distinct guidelines for geological data to be used in the research and the cost increase force the researchers to represent a simplified assessment. Materials and methods. The control of different WHP zone size geological parameters was studied by applying a series of theoretical calculations. Thus, software for analytical modelling of groundwater wells ANSDIMAT developed by the Institute of environmental geoscience, RAS, was used. Delineation of WHP zones is performed by the Particle-Tracking method. Results. Both size and geometry of WHP zones are controlled by several geological and hydrogeological parameters, which entail a synergetic effect. Within the parameters mentioned above, there are such as 1) pumping discharge; 2) aquifer thickness; 3) accessible porosity; 4) flow direction and the hydraulic gradient; 5) hydraulic conductivity; 6) the hydraulic connectivity of an aquitard. Our research shows all six factors perceptibly influence the results. To avoid significant errors each of the factors should be taken into account. Conclusion. Regulations actualization and the Guideline for delineation of wellhead protection zones, in particular, remain to be an area for improvement. Clear requirements for geological and hydrogeological parameter contamination, parameters uncertainty.

Photogrammetry for Free Surface Flow Velocity Measurement: From Laboratory to Field Measurements

This study describes a multi-camera photogrammetric approach to measure the 3D velocity of free surface flow. The properties of the camera system and particle tracking velocimetry (PTV) algorithm were first investigated in a measurement of a laboratory open channel flow to prepare for field measurements. The in situ camera calibration methods corresponding to the two measurement situations were applied to mitigate the instability of the camera mechanism and camera geometry. There are two photogrammetry-based PTV algorithms presented in this study regarding different types of surface particles employed on the water flow. While the first algorithm uses the particle tracking method applied for individual particles, the second algorithm is based on correlation-based particle clustering tracking applied for clusters of small size particles. In the laboratory, reference data are provided by particle image velocimetry (PIV) and laser Doppler velocimetry (LDV). The differences in velocities measured by photogrammetry and PIV, photogrammetry and LDV are 0.1% and 3.6%, respectively. At a natural river, the change of discharges between two measurement times is found to be 15%, and the corresponding value reported regarding mass flow through a nearby hydropower plant is 20%. The outcomes reveal that the method can provide a reliable estimation of 3D surface velocity with sufficient accuracy.

Why Does Western Indian Ocean Circulation Connectivity Matter?

<p>Marine circulation connectivity describes the pathways and timescales over which spatially separated parts of the ocean are connected by oceanic currents. In the Western Indian Ocean (WIO), these pathways and associated timescales are characterised by pronounced seasonal and interannual variability, including monsoon-driven reversal of surface currents in the northern part of the basin.</p><p>Understanding the connectivity timescales in the WIO – and their variability – is important for a multitude of reasons. Ecological connectivity between coral reefs is necessary to maintain their biodiversity, understanding downstream connectivity from marine resource exploitation sites is important to understand which areas are likely to be affected, and circulation connectivity is a key concern when designing marine conservation measures. For example, establishing an effective network of marine protected areas (MPAs) requires that they are connected on ecologically relevant timescales (e.g. the duration of species’ pelagic larval stages), but gaps in the existing MPA network mean that decisions need to be undertaken about which areas to prioritise for future protection. Therefore, knowledge of the advective pathways connecting the WIO over these timescales is essential for effective management of the region.</p><p>Here, a Lagrangian particle tracking method is used in conjunction with a 1/12° resolution ocean model to elucidate the advective pathways mediated by major surface currents in the WIO. Model experiments are performed with virtual particles released into several major WIO currents and tracked for 100 days, and the resulting trajectories are analysed. Significant variability was found, with advective pathways and timescales sensitive to both season and year of release. The main differences are associated with the different monsoon regimes driving changes in connectivity timescales, and reversing direction of advective pathways in the north of the WIO. In addition to this seasonal variability, interannual changes are explored. Case studies of anomalous connectivity pathways / timescales are presented and discussed in the context of extremes in forcing and larger scale variability, including the Indian Ocean Dipole.  </p>

Visualization Method for the Cell-Level Vesicle Transport Using Optical Flow and a Diverging Colormap

Elucidation of cell-level transport mediated by vesicles within a living cell provides key information regarding viral infection processes and also drug delivery mechanisms. Although the single-particle tracking method has enabled clear analysis of individual vesicle trajectories, information regarding the entire cell-level intracellular transport is hardly obtainable, due to the difficulty in collecting a large dataset with current methods. In this paper, we propose a visualization method of vesicle transport using optical flow, based on geometric cell center estimation and vector analysis, for measuring the trafficking directions. As a quantitative visualization method for determining the intracellular transport status, the proposed method is expected to be universally exploited in various biomedical cell image analyses.

Mathematical Modelling and Simulation of liquid steel flow phenomena and temperature distribution in an optimized tundish design of a continuous caster

The objective of this study was to analyze the fluid flow of molten steel in a continuous casting tundish using numerical simulations for better inclusion floatation and its separation. The tundish geometry was designed using Autodesk FUSION 360 and the analysis were performed on ANSYS FLUENT. The investigations were done on steady-state as well as transient conditions. To scale back vortexing and turbulence within the tundish, turbo stoppers and flow modulators, e.g. dam and weirs were placed for an optimized and efficient flow inside the tundish and its behavior on the spacious flow structure was explored. The strategic placements of the flow modifiers produced higher turbulence in the recess region of the tundish resulting in better turbulent flow withinside the inlet region of the tundish. Thereby a more homogeneous fluid flow is formed with better conditions for particle separation. Analysing the flow behavior we have determined the inclusion floatation using particle tracking method form dense discrete phase modelling along with multiphase eulerian-lagragian model. Reduction in dead volumes was achieved in the spatial flow due to better intermixing which further reduced the metal loss and increased the yield of the tundish using the fluid flow analysis. Analyzing eddy formations in the spatial geometry of the tundish structure made it easy to evenly distributes the flow-induced shear. This determined the lesser turbulence on the free surface of the steel flow resulting in less reduction of the liquid steel surface.

Particle Tracking Random Simulation of Pollutant Migration and Diffusion

A two-step Lagrangian particle tracing method was used to simulate the particle movement in convective diffusion. Firstly, the flow field distribution was given by finite difference method. Secondly convective diffusion was simulated by particle tracing method. Jet current through centre slit in the static flow and turbulent flow as well as the side discharge of pollutant were simulated as case study. In this paper, finite difference method is used to solve fluid velocity field distribution, and particle tracking method is used to solve convection-diffusion equation. The result shows that the data produced by particle tracing method is reasonable and the method is stable. This method can be applied to the calculation of the convective diffusion of pollutant and spread to other problems.