Equipotential Lines Research Articles

Ідентифікація координат імпульсних джерел забруднень стічних вод в кусково-однорідних середовищах числовими методами квазіконформних відображень

The process of filtration in a single-connected curvilinear domain bounded by streamlines and equipotential lines is considered, provided that the medium under study is piecewise homogeneous. It is assumed that certain unknown curves act as impulse sources of pollution. It is assumed that their propagation occurs only due to the convective component, without significantly affecting the filtration background. It is proposed to use the method of characteristics for solving the convection equation to identify the coordinates of pollution sources. In this case, quasipotentials at the fluid inlet and outlet at the boundary of the domain, coordinates of the points of pollution detection, and the time of its movement downstream can serve as a priori data. The general algorithm involves the adaptation of the numerical quasiconformal mapping method to build a hydrodynamic mesh, according to which the coordinates of pollution sources are identified. Numerical experiments were carried out and analysed. In particular, it is emphasised that with a sufficient mesh division, the maximum discrepancies between the a priori known data and the calculated data are small compared to the size of the studied domain. This indicates the effectiveness of the developed algorithm for identifying pollution sources in the case of a piecewise homogeneous environment. As an additional measure to reduce the magnitude of the uncertainties, it is proposed to use more accurate approximation schemes for specific expressions. On the other hand, there is an increase in computational complexity compared to the case of a continuous setting of the filtration coefficient. Given the relatively high accuracy of the calculations, it seems advisable to further develop an described approach to larger-scale in comparison with point sources of pollution and to spatial case. Taking into account the sensitivity of the solutions to the discontinuity of the filtration coefficient values, it is also worthwhile to introduce additional conditions at the contact of homogeneous media in the future.

A novel method for highly linear gradient coil design based on stream function.

Magnetoencephalography (MEG) and magnetic resonance imaging (MRI) are non-invasive imaging techniques that offer effective means for disease diagnosis. A more straightforward and optimized method is presented for designing gradient coils which are pivotal parts of the above imaging systems. A novel design method based on stream function combining an optimization algorithm is proposed to obtain highly linear gradient coil. Two-dimensional Fourier expansion of the current field on the surface where the coil is located and the equipotential line of the expansion term superposition according to the number of turns of the coil are used to represent the coil shape. Particle swarm optimization is utilized to optimize the coil shape while linearity and field uniformity are used as parameters to evaluate the coil performance. Through this method, the main parameters such as input current distribution region, coil turns, desired magnetic field strength, expansion order and iteration times can be combined in a given solution space to optimize coil design. Simulation results show that the maximum linearity spatial deviation of the designed bi-planar x-gradient coil compared with that of target field method is reduced from 14% to 0.54%, and that of the bi-planar z-gradient coil is reduced from 8.98% to 0.52%. Similarly, that of the cylindrical x-gradient coil is reduced from 2% to 0.1%, and that of the cylindrical z-gradient coil is reduced from 0.87% to 0.45%. The similar results are found in the index of inhomogeneity error. Moreover, it has also been verified experimentally that the result of measured magnetic field is consist with simulated result. The proposed method provides a straightforward way that simplifies the design process and improves the linearity of designed gradient coil, which could be beneficial to realize better magnetic field in engineering applications.

Visualization method of mechanical power exposure intensity and duration in mechanical ventilation patients

To visualize the relationship between different combinations of mechanical power exposure intensity-duration and death risk in mechanical ventilation patients using a visualization method. Critically ill patients receiving mechanical ventilation were selected from the Medical Information Mart for Intensive Care- IV v1.0 (MIMIC- IV v1.0) database. The patients were divided into four subgroups according to oxygenation index (PaO2/FiO2) including > 300 mmHg (1 mmHg ≈ 0.133 kPa) group, 201-300 mmHg group, 101-200 mmHg group and ≤100 mmHg group. The baseline characteristics, ventilator parameters, and prognostic indicators for different patient populations were collected. For each patient, the mechanical power thresholds from low to high (5-30 J/min, increasing at intervals of 1 J/min) were used to evaluate the different exposures of mechanical power (above the set threshold was recorded as one exposure), and the number of events with different exposure intensity-duration combinations was counted based on their corresponding durations. Based on the 28-day survival/non-survival status, the number of exposures for survivors and non-survivors in each exposure intensity-duration combination was calculated, and the survival odds ratio (OR) for different mechanical power exposure intensity-duration combinations was subsequently computed. Two-dimensional tables were generated with mechanical power exposure duration on the x-axis and exposure intensity on the y-axis, and the heatmap and its corresponding equipotential line view were used to visualize the OR value to assess the risk of death. A total of 5 378 patients receiving mechanical ventilation were enrolled in the study, of whom 2 069 patients in the PaO2/FiO2 > 300 mmHg group, 813 patients in the 201-300 mmHg group, 1 493 patients in the 101-200 mmHg group, and 1 003 patients in the ≤100 mmHg group. The severity scores of patients, including sequential organ failure assessment (SOFA) score and simplified acute physiology score II (SAPS II), gradually increased following the decrease in PaO2/FiO2, and the incidence of co-morbidities also gradually increased. In terms of ventilator parameters, mechanical power was increased gradually with decrease in PaO2/FiO2, measuring 10.4 (7.8, 13.9), 11.3 (8.5, 14.7), 13.6 (10.0, 18.2), and 16.7 (12.5, 22.0) J/min (P < 0.01). In terms of prognosis, 28-day mortality of patients was gradually increased with decrease in PaO2/FiO2 [29.1% (601/2 069), 26.9% (219/813), 28.1% (420/1 493), and 33.3% (334/1 003), respectively, P < 0.05]. In the heatmap, it could be observed that the 28-day death risk of mechanical ventilation patients was gradually increased with increase in mechanical power exposure intensity and long duration, showing two distinct areas: a region near the bottom left corner (representing low mechanical power exposure intensity and short duration) was blue, indicating a greater chance of survival. In contrast, another region near the top right corner (representing high mechanical power exposure intensity and long duration) was red, indicating a higher risk of death. According to the fitted lines of death risk, for the same risk of death, a shorter mechanical power exposure duration was required for higher exposure intensity, while lower mechanical power exposure intensity required a longer exposure duration. The above trend of change was similarly reflected in the overall population and different oxygenation populations. Cumulative mechanical power exposure to higher intensity and/or longer duration is associated with worse outcomes in mechanical ventilation patients. Considering both the mechanical power exposure intensity and duration may help to evaluate the effectiveness of lung protection in mechanical ventilation patients and guide adjustments in mechanical ventilation strategy to reduce the risk of ventilator-induced lung injury.

Analysis of heating defects in extension rods of extra-high voltage direct current overhead transmission lines

This paper studies the overheating defect of an extension rod in a ± 800 kV extra-high voltage direct current overhead transmission line, and proposes various factors that affect the overheating of the extension rod. Establish an equivalent model of an extra high voltage DC transmission line based on equipotential point and line parameter analysis, and calculate the model parameters. The proposed model can also be applied to ultra-high voltage DC overhead transmission lines such as ± 500 kV, and has strong universality. Simulation experiments show that if the equivalent resistance value of the split wire side is reduced by 0.01Ω, the power loss on the extension tie rod can be increased to 380.951 W; if the equivalent resistance value of the jumper side is increased by 0.01Ω, the power loss on the extension tie rod can be increased to 273.41 W. Combined with theoretical analysis and simulation verification, it is concluded that the main factor affecting the overheating of the extension rod is the change in the resistance value on the jumper side caused by the increase in contact resistance. A systematic troubleshooting plan for related defect problems is proposed, which has important reference and guidance significance for such line fault problems.

Controllable concentric electric field line distribution for simultaneous separation of DNA

An approach for the controllable separation and concentration of nucleic acid using a circular nonuniform electric field was proposed and developed. Using six different lengths of DNA molecules as standard samples, the distribution of the gradient electric field was increased from the outer circular electrode to the inner rod-shaped electrode, contributing to the migration of DNA molecules at a velocity gradient towards the region with the strongest inner electric field. The DNA molecules were arranged in a distribution of concentric circles that aligned with the distribution of concentric equipotential lines. The concentration of DNA multiplied with the alternation of radius. As a result, this platform allowed simultaneous DNA separation, achieving a resolution range of 1.17–3.03 through an extended electrophoresis time, resulting in enhanced concentration factors of 1.08–6.27. Moreover, the manipulation of the relative height of the inner and outer electrodes enabled precise control over the distribution and the deflection degree of electric field lines, leading to accurate control over DNA deflection.

A novel interfacial resistance-free bifunctional camouflage device in thermal–electric fields

A novel interfacial resistance-free (IRF) bifunctional camouflage (transparent and invisible) device is proposed in this paper. The thermal and electric conductivities of the shell and background are the same to eliminate the interfacial resistance. The IRF bifunctional camouflage device can operate in thermal–electric fields based on the neutral inclusion method. The distribution of isotherm and equipotential lines are studied quantitatively by the simulations. It is confirmed that the IRF bifunctional camouflage device with arbitrary natural materials can effectively achieve not only the invisible function but also the transparent function in thermal–electric fields. This method provides a window to the realization of bifunctions and the development of multi-physics fields.

Mandelbrot Set as a Particular Julia Set of Fractional Order, Equipotential Lines and External Rays of Mandelbrot and Julia Sets of Fractional Order

This paper deepens some results on a Mandelbrot set and Julia sets of Caputo’s fractional order. It is shown analytically and computationally that the classical Mandelbrot set of integer order is a particular case of Julia sets of Caputo-like fractional order. Additionally, the differences between the fractional-order Mandelbrot set and Julia sets from their integer-order variants are revealed. Equipotential lines and external rays of a Mandelbrot set and Julia sets of fractional order are determined.

Research on Intelligent Vehicle Operation Risk Assessment and Early Warning Based on Predictive Risk Field

In order to enhance the driving safety of intelligent vehicles in complex road scenarios, a method for vehicle operation risk assessment and early warning based on the predictive risk field is proposed. The temporal feature vector composed of the spatiotemporal state characteristics of the ego vehicle and surrounding traffic participants is taken as input data for the Attention‐Bidirectional Long‐Short Term Memory (Attention‐BiLSTM) model, which is trained to establish the desired mapping relationship. By predicting the motion state of the target vehicle and utilizing an improved risk field model based on the target vehicle of heading angle, the predictive risk field is obtained. This allows for the assessment of the ego vehicle operational risks. The risk warning model is integrated to provide risk early warning, and the safety path for the ego vehicle is planned based on the interaction between the predictive risk field equipotential lines and the cubic spline curves. Experimental results demonstrate that the proposed vehicle operation risk assessment and early warning model is effective in providing early warnings and safe path references for the ego vehicle in complex urban road test scenarios.

Continuum and Equivalent Circuit Modelling of Porous Electrode Charging

The flow of electrolytes through pores is important in various fields of science and technology. Examples range from axons in the brain and plasmodesmata in plant cells to energy storage in batteries and supercapacitors. In the porous carbon electrodes of supercapacitors, ions move over micrometers through macropores until they arrive at nanopores, forming so-called electrical double layers. In this presentation, I discuss several models for this multi-scale charging process. First, I present analytical [1] and finite-element solutions [2,3] to the Poisson-Nernst-Planck (PNP) equation for the charging of cylindrical electrolyte-filled pores [Figure (a)]. With these methods, I will delineate the validity of the famous “transmission line” circuit model developed by de Levie in the 1960s [4,5] [Figure (b)]. The TL model assumes equipotential lines in a pore to be straight, which is not the case at a pore’s entrance and end, see Figure (a). As a result, the TL model does not accurately describe short-pore charging. Related, the impedance of short pores deviates from the impedance of the TL circuit (the “Warburg open” impedance Wo), especially at high frequencies, see Figure (c).Figure Caption: (a) The electrostatic potential in a cylindrical pore next to an electrolyte reservoir of resistance Rb shortly after applying a potential step. The data represent numerical solutions to the Poisson-Nernst-Planck (PNP) equations, which we solved with finite elements using a Newton solver from the FEniCS library. (b) The transmission line circuit is an equivalent circuit that describes the charging of pores such as the one shown in panel (a). In the circuit, the resistance R and capacitance C of the pore are cut into small pieces r and c. (c) The impedance of the TL circuit is given by Rb +Wo (blue dotted line), where Wo is the Warburg open impedance. Also shown is the impedance of a pore whose length is five times its diameter, as obtained from numerical PNP simulations (black). T. Aslyamov and M. Janssen, Electrochim. Acta 424, (2022)J. Yang, M. Janssen, C. Lian, R. van Roij, J. Chem. Phys. 156, (2022)C. Pedersen, T. Aslyamov, M. Janssen, in preparation R. de Levie, Electrochim. Acta 8, (1963)M. Janssen, Phys. Rev. Lett. 126, (2021) Figure 1

ROLE OF ST SEGMENT RESOLUTION ALONE AND IN COMBINATION WITH THROMBOLYSIS IN MYOCARDIAL INFARCTION (TIMI) FLOW IN PRIMARY PERCUTANEOUS CORONARY INTERVENTION FOR ST SEGMENT ELEVATION MYOCARDIAL INFARCTION

This study aimed to assess the effect of ST-segment resolution (STR) alone and in combination with TIMI flow after primary percutaneous coronary intervention (PPCI) for ST-segment elevation myocardial infarction (STEMI). The study was conducted at the Department of Cardiology, Peshawar Institute of Cardiology, Hayatabad Peshawar, KPK, from August 2022 to July 2023. Ninety patients with acute myocardial infarction were enrolled, and STR was considered successful if it reached 50% or complete STR (ST-segment back to the equipotential line). TIMI flow was evaluated after PPCI, and the primary outcome was two-year all-cause mortality. Results showed that each STR &lt;50%, STR ≥50%, and complete STR occurred in 33.3% of the patients. Successful STR was the only independent predictor of 2-year death among all clinical factors. Combining TIMI flow and STR showed different 2-year mortality rates in subgroups; the lowest was seen in successful STR and TIMI 3 flow, the middle when either of these measures was decreased, and the greatest when both were abnormal. The study concluded that analyzing both STR and TIMI flow provides additional prognostic information beyond what either measure could provide. Therefore, it can be used as a reliable and convenient surrogate endpoint for determining successful PPCI. Additionally, the study found that post-PPCI STR is a strong long-term prognosticator for ST-segment elevation myocardial infarction.

Assessment of Groundwater Response Scenarios for Surrounding Areas After Filling the Proposed Badush Dam Reservoir, Northern Iraq

In the current study, the depth of groundwater was detected in (39) wells in the banks surrounding Tigris River between Mosul and Badush dams, and then the maps of depth and level of groundwater were drawn. To predict the response of groundwater behavior in the banks of Badush reservoir in the strips adjacent to the river when starting the filling process, the lines of selected water levels in Badush dam were plotted on the map of groundwater equipotential lines to detect the areas confined between the water level in the reservoir and the same level for groundwater. It is assumed that these areas are affected by the bank storage; therefore, they are prone to leakage or geotechnical problems within the zone of engineering facilities foundations including Badush Dam itself, the regulatory dam and infrastructure projects. In the pre-storage stage, it is noted that the area of influence of the bank storage is very limited and does not exceed 2 km2 on each side of the river in the area very close to the dam. When the water level raises more at the beginning of the storage, the area of influence of the bank storage will extend towards the upstream close to the river meandering. The effect on the eastern bank (left) will be wider compared to the situation in the western bank (right) where the effect is limited. The eastern side is characterized by having a higher population density and more urban establishments; therefore, the foundations of these establishments will be more affected. The area affected by the bank storage continues to widen towards upstream with the increase in the level of the dam reservoir until the effect reaches the maximum limit and approaches the shoulders of the regulatory dam, when the water levels in Badush reservoir are more than 245 m above sea level (a. s. l.). The variation in the groundwater extension effect with the continuous or gradual filling of reservoir requires monitoring and caution during filling, for fear of affecting the geotechnical properties of the soil and rocks within the foundations zone, and thus affecting the stability of the two dams.

IDENTIFICATION OF SEPARATION CURVES OF STRONGLY CONTRASTING ENVIRONMENTS USING COMPLEX ANALYSIS METHODS

When modeling mass transfer processes (for example, filtration) in porous media, there may be cases of the existence of highly permeable layers, which are separated from the corresponding studied parts by some curves that must be found (identified) in the process of solving the problem. When constructing a mathematical model of the corresponding physical process, we will consider a highly permeable medium as "ideally (theoretically infinitely) permeable." In this case, the desired curve can be considered an equipotential line. This work considers the stationary process of fluid movement in a homogeneous horizontal layer of infinitely large dimensions - a soil massif, which is limited by infinite sections of curves, in particular by the desired curve of theoretical water resistance and the horizontal axis, on which the local speed of movement is known. On the basis of the methods of conformal reflections and total images, an approach to the identification of the curve of the separation of media is proposed. The constructed algorithm is modified for solving nonlinear inverse boundary value problems on quasi-conformal mappings of curvilinear polygonal regions bounded by uncertain streamlines and equipotential lines. The feature of the method proposed is that the summary representation formulae allow to explicitly write the solution to the localized linear (main) part of the obtained system of equations. The unknown coefficients are determined here by solving a non-linear system generated solely by the boundary conditions and numerical analogues of the Cauchy–Riemann equations.

Measured Rainfall Infiltration and the Infiltration Interface Effect on Double-Layer Loess Slope

It is of great theoretical and engineering significance to carry out field rainfall tests and research on double-layer soil slopes in loess areas. Based on the developed rainfall simulation system with slow-moving injection, field rainfall tests were carried out on a natural double-layer loess slope. The characteristics of volumetric water content were monitored, and the rainfall infiltration characteristics and infiltration effect at the interface of the soil layer were analyzed by numerical simulation. The results showed the fastest infiltration at the top platform of the slope, followed by that at the upper surface of the slope, and the slowest infiltration at the lower surface of the slope during rainfall. Under various rainfall intensities, the erosion of the upper silty loess slope was greater than that of the lower clay loess slope, and the erosion patterns were quite different at the end of rainfall. During the infiltration process in the double-layer loess slope, a stagnant transition area was formed near the interface of the soil layer. The equipotential line of water content in the stagnant transition area of the upper region was roughly parallel to the slope surface, and the equipotential line in the lower region was roughly parallel to the interface of the soil layer. With an increase in rainfall intensity, the upper transition area at the interface of the soil layer continued to extend from the slope surface inward, showing the interface infiltration effect that became increasingly significant with the intensification of rainfall. The infiltration effect at the soil layer interface could provide an evaluation basis for rainfall infiltration analyses of multi-layer soil slopes.

Identification of Ionization Region Profile and Potential Distribution in Welding Arc Plasma by Direct Probe Detection

A special probe detection system and analyzing method were designed for estimating the ionization region in welding arc. Results showed that ionization region in gas tungsten welding arc is in spindle shape. Arc plasma prefers to contract near anode workpiece. The arc volume increases with the increase of welding arc current accordingly. With the decrease of arc length, the arc expands in radius direction. Electrical equipotential lines nearly parallel the anode surface and tend to bend to the tungsten electrode in the region near cathode. Voltage drop near the cathode dominates the arc voltage when arc current changes.

EPL-PRM: Equipotential line sampling strategy for probabilistic roadmap planners in narrow passages

Path planning is a crucial concern in the field of mobile robotics, particularly in complex scenarios featuring narrow passages. Sampling-based planners, such as the widely utilized probabilistic roadmap (PRM), have been extensively employed in various robot applications. However, PRM’s utilization of random node sampling often results in disconnected graphs, posing a significant challenge when dealing with narrow passages. In order to tackle this issue, we present equipotential line sampling strategy for probabilistic roadmap (EPL-PRM), a novel approach derived from PRM. This paper initially proposes a sampling potential field, followed by the construction of equipotential lines that are denser in the proximity of obstacles and narrow passages. Random sampling is subsequently conducted along these lines. Consequently, the sampling strategy enhances the likelihood of sampling nodes around obstacles and narrow passages, thereby addressing the issue of sparsity encountered in traditional sampling-based planners. Furthermore, we introduce a nodal optimization method based on an artificial repulsive field, which prompts sampled nodes to move in the direction of repulsion. As a result, nodes around obstacles are distributed more uniformly, while nodes within narrow passages gravitate toward the middle of the passages. Finally, extensive simulations are conducted to evaluate the proposed method. The results demonstrate that our approach achieves path planning with superior efficiency, lower cost, and higher reliability compared with traditional algorithms.

Simulation of asymmetrical rotational flow in the flow part of a well jet pump

In order to improve the mathematical model of the working process of the above-bit ejection system for the conditions of its asymmetric rotation in the well, a method of modeling the circulating injected flow using a hydrodynamic vortex function, the center of which is shifted relative to the axis of the mixing chamber of the jet pump, has been developed. In the process of modeling the rotating asymmetric movement of the injected flow, the concept of circulation of the vector of the translational velocity of the liquid along a closed circuit is used. With the help of the components of the complex potential of the hydrodynamic circulation function, a graphical interpretation of the equipotential lines and flow lines of the spatial vortex with one-sided and two-sided displacement of the coordinate center was obtained. Using analytical relations for the velocity potential and stream function, the components of the circulation velocity are determined and the analyticity of the function of the complex potential with a shifted vortex center is proven. The fulfillment of the Cauchy-Riemann conditions allowed us to present the resulting velocity of the circulating current with the coordinate center shifted along the vertical axis in the form of a partial derivative of the complex potential. In contrast to the complex potential for a symmetric vortex, the ratio for determining the circulation speed in case of misalignment of the working nozzle and the mixing chamber of the jet pump contains an additional component in the form of the displacement of the vortex center.In the process of analyzing the results of using the proposed mathematical model, it was established that the resulting speed of the circulation current and the relative displacement of the spatial vortex center are directly proportional. The conducted studies proved that the ratio of the velocities of the symmetric and asymmetric circulation flow is a function of the displacement of the center of the vortex flow coordinates and varies from 1 to zero. The magnitude of the relative speed of the circulation flow is inversely proportional to the displacement of the coordinate center and the distance to the mixing chamber of the jet pump. The developed mathematical model can be used to predict the influence of the rotation of the ejection system on its pressure characteristic in the case of radial relative displacement of the working nozzle and the mixing chamber of the jet pump.

Mathematical modeling of fluid flow and pollutant transport in a homogeneous porous medium in the presence of plate stacks

This study aims at investigating the numerical analysis of pollutant transport in homogeneous porous media with solid plate stacks. The investigation was performed for solid/impervious objects of the same size placed in homogeneous porous media. The pollutant transport equation (i.e., steady-state and time dependent advection-dispersion) chosen in mathematical modeling. Three cases arise on the basis of dispersion coefficients: (a) when dispersion is uniformly constant, (b) when dispersion depends upon magnitude of the velocity, and (c) when dispersion depends upon magnitude of the velocity and directional dispersivities, all these are discussed in detail. Generally, analytical solution of such problems doesn't exist, so all the work is done numerically. The governing partial differential equation of pollutant concentration is approximated by using finite difference technique. Central, one-sided, backward and forward finite difference formulae of the same order are used to discretize the domain.Simulations of velocity potential and stream function are approximated by Matlab software. Then equipotential lines and streamlines are visualized in the form of contours. Both, velocity potential and stream function are harmonic and satisfy Laplace's equation. Fluid flow lines and pollutant concentration are represented graphically for several parameters involved in the study.It is found that entrance/exit length, shape, hydraulic conductivity, the number and position of impervious objects affect the fluid flow and pollutant transport. However, there is no significant affect of heated objects on pollutant transport. Moreover, advection and dispersion depend upon permeability of porous media and properties of solid matrix.To authenticate the Matlab scheme of finite difference, it is verified that fluid as well as pollutant fluxes (in and out) are equal. Moreover, time-dependent problem converges to steady-state form after very long time.For monitoring or forecasting the build up of contamination concentration, the pollutant transport model is considerable. As this model is affected by different parameters which are discussed above, can helps to overcome the pollutant accumulation. The solid object is main key to lessen the contamination in the underground. If the entrance or leakage point of the domain is blocked by impermeable object or filled the vertical column with material of low hydraulic conductivity it ultimately slows down or even refrains the pollutant particles to pass through. The pollutant concentration is also minimized by injecting the bioremedial agents with the help of treatment columns.

Underwater Pollution Tracking Based on Software-Defined Multi-Tier Edge Computing in 6G-Based Underwater Wireless Networks

The forthcoming 6G networks are expected to provide a vision of overlapping aerial-ground-underwater wireless networks. Meanwhile, the rapid development of the Internet of Underwater Things (IoUTs) brings forth many categories of Autonomous Underwater Vehicle (AUV)-assisted Underwater Wireless Networks (UWNs). In this paper, we argue that the AUV-assisted UWNs can be intelligently utilized to track underwater pollution. To perform smart underwater pollution tracking, we propose the paradigm of AUV flock-based networking system and Software-Defined Networking (SDN)-enabled AUV flock Networking System (SDN-AUVNS). We introduce the concept of Mobile Edge Computing (MEC) into the control of SDN-AUVNS and propose the upgrade of the control plane of the SDN-AUVNS to with the multi-tier edge computing ability. By the proposed system architecture, we adopt the artificial potential field theory to construct the network controlling model. And we present the underwater tracking model for SDN-AUVNS, especially for the underwater pollution equipotential line of a particular concentration. Furthermore, to provide accurate path planning for the equipotential line tracking, we utilize the linearizability mechanism to optimize and revise the control input for the SDN-AUVNS. Lastly, we give a fast united control algorithm that can intelligently schedule the SDN-AUVNS to track underwater pollution equipotential lines. In particular, we propose a smart approach with the name of ’Inverse Distance Weighting’ to optimize the detection sample of the SDN-AUVNS. Evaluation results indicate that our proposal is able to track/survey the equipotential lines within a satisfactory error.

Research on insulation state evaluation and detection technology for 40.5 kV switchgear wall bushing

Wall bushing is the core insulator of 40.5 kV air insulation switchgear, and its insulation performance determines the insulation level and service life of the switchgear. Wall bushing often appears partial discharge, insulation aging, grounded breakdown, and other problems after a period of operation. The main reason is the partial discharge of the equipotential line for the wall bushing. In this paper, the influence of the wall bushing equipotential line on the electric field distribution is systematically analyzed to improve the operating reliability and service life of the 40.5 kV wall bushing. Based on the electric field simulation of the equipotential line, the feasibility of the traditional live detection method is given. The characteristic gas detection method is proposed through air electrolysis, thermal decomposition, early warning of the development trend of the internal suspension defect state. Finally, it proposes corresponding preventive measures to avoid the development of internal suspension defect of wall bushing into a sudden grounding, and ensure the reliability of the system operation.

Hydrochemistry and stable isotopes revealed focused and diffuse recharge processes in the Sonora River basin, Mexico

ABSTRACT A hydro-geochemical characterization was conducted in the northern part of the Sonora River basin, covering an area of 9400 km2. Equipotential lines indicated that groundwater circulation coincided with the surface water flow direction. Based on the groundwater temperature measured (on average ∼21 °C), only one spring exhibited thermalism (51 °C). Electrical conductivity (160–1750 μS/cm), chloride and nitrate concentrations (>10 and >45 mg/L) imply highly ionized water and anthropogenic pollution. In the river network, δ 18O values revealed a clear modern meteoric origin. Focused recharge occurred mainly from the riverbeds during the rainy season. During the dry season, diffuse recharge was characterized by complex return flows from irrigation, urban, agricultural, mining, and livestock. Drilled wells (>50 m) exhibited a strong meteoric origin from higher elevations during the rainy season with minimal hydrochemical anomalies. Our results contribute to the knowledge of mountain-front and mountain-block recharge processes in a semi-arid and human-altered landscape in northern Mexico, historically characterized by limited hydrogeological data.