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Wyniki wyszukiwania dla: LEAKAGE CURRENTS
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Hostility bias or sadness bias in excluded individuals: Does anodal transcranial direct current stimulation of right VLPFC vs. left DLPFC have a mitigating effect?
PublikacjaExclusion has multiple adverse effects on individual’s well-being. It induces anger and hostile cognitions leading to aggressive behavior. The purpose of this study was to test whether exclusion would affect recognition of anger on ambivalent faces of the excluders. We hypothesized that exclusion would elicit more anger encoding (hostility bias) than inclusion, but this effect would be mitigated by anodal tDCS of right VLPFC...
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Investigating the current environmental situation in the Middle East and North Africa (MENA) region during the third wave of COVID-19 pandemic: urban vs. rural context
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Production of antimicrobial silver nanoparticles modified by alkanethiol self‐assembled monolayers by direct current atmospheric pressure glow discharge generated in contact with a flowing liquid anode
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Comparison of the performance of direct current atmospheric pressure glow microdischarges operated between a small sized flowing liquid cathode and miniature argon or helium flow microjets
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Direct current atmospheric pressure glow discharge generated between a pin-type solid cathode and a flowing liquid anode as a new tool for silver nanoparticles production
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Combination therapy in the management of hypertension — current problem in Poland. Expert consensus statement of the Polish Society of Hypertension and Polish Cardiac Society Working Group on Cardiovascular Pharmacotherapy
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Current trends in analytical strategies for determination of polybrominated diphenyl ethers (PBDEs) in samples with different matrix compositions – Part 1.: Screening of new developments in sample preparation
PublikacjaPolybrominated diphenyl ethers (PBDEs) are ubiquitous compounds in the environment. Restrictions on the use of PBDEs introduced at the beginning of the 21st century have not eliminated these highly persistent and bioaccumulative compounds from the environment. Despite many existing regulations to control and phase out, extensive research on PBDEs is still necessary to fully evaluate the hazard their create to the environment. In...
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Finite Element Method Applied in Electromagnetic NDTE: - A Review
PublikacjaThe paper contains an original comprehensive review of finite element analysis (FEA) applied by researchers to calibrate and improve existing and developing electromagnetic non-destructive testing and evaluation techniques, including but not limited to magnetic flux leakage (MFL), eddy current testing, electromagnetic-acoustic transducers (EMATs). Premium is put on the detection and modelling of magnetic field, as the vast majority...
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Design and experimental verification of multi-layer waveguide using pin/hole structure
PublikacjaThis study presents a novel technique for minimizing RF leakage in metallic hollow waveguides fabricated using the multilayer split-block method. By integrating a pin/hole wall into the split-block multilayers, a substantial reduction of RF leakage can be achieved while reducing the circuit size and mitigating the performance variations. To validate the proposed approach, a slot antenna fed by single ridge waveguide has been prototyped...
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Hydro Lubricants: Water-based lubricants for hydropower applications
PublikacjaSeveral different base oil types exist in the market including mineral and synthetic oils (e.g. polyalphaolefins, ester, polyglycol, etc.) and are currently widely in use. Although synthetic oils have drawn great attention over the past few decades in terms of their tribological benefits, mineral oils are still widely used in hydropower applications due primarily to their low cost and easy miscibility with other oils. However,...
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The effect of a miniature argon flow rate on the spectral characteristics of a direct current atmospheric pressure glow micro-discharge between an argon microjet and a small sized flowing liquid cathode
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The improvement of the analytical performance of direct current atmospheric pressure glow discharge generated in contact with the small-sized liquid cathode after the addition of non-ionic surfactants to electrolyte solutions
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Pulse-Modulated Radio-Frequency Alternating-Current-Driven Atmospheric-Pressure Glow Discharge for Continuous-Flow Synthesis of Silver Nanoparticles and Evaluation of Their Cytotoxicity toward Human Melanoma Cells
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Wpływ falistości pierścienia ślizgowego na rozpływ prądu w zestyku ślizgowym maszyny synchronicznej = Influence of slip-ring waviness on current distribution in the sliding contact of a synchronous machine
PublikacjaZestyk ślizgowy maszyny synchronicznej średniej i dużej mocy zawiera na ogół szereg równolegle pracujących szczotek na każdym z pierścieni. Szczotki znajdują się w oprawkach szczotkowych rozmieszczonych przestrzennie wzdłuż obwodu pierścienia. To sprawia, że pracują one w tej samej chwili czasowej na różnych fragmentach pierścienia ślizgowego. Nierównomierny rozpływ prądu może spowodować nadmierne obciążenie niektórych szczotek....
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Evaluation of fire hazard in electrical installations due to unfavorable ambient thermal conditions
PublikacjaEvaluation of fire hazard caused by electrical installations is a difficult and important topic, and it limits the possibility of loss of life or health of people, as well as the occurrence of significant property damage. In particular, this hazard was caused by power cables and especially photovoltaic (PV) installations. The authors proved that power cables directly exposed to strong solar radiation are likely to exceed maximum...
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Bidirectional Fragment to Fragment Links in Wikipedia
PublikacjaThe paper presents a WikiLinks system that extends the Wikipedia linkage model with bidirectional links between fragments of the articles and overlapping links’ anchors. The proposed model adopts some ideas from the research conducted in a field of nonlinear, computer-aided writing, often called a hypertext. WikiLinks may be considered as a web augmentation tool but it presents a new approach to the problem that addresses the specific...
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Compensation of Dead Time Effects for Shunt Active Power Filters
PublikacjaThe paper presents a comprehensive approach to the compensation of the grid current distortion for shunt active power filter systems. Four different sources of current distortion are addressed: imperfect grid synchronization caused by the distortion in the grid voltages, time delays in the estimation of compensating currents and grid voltages, fluctuations of the dc bus voltage, and the distortion of inverter output voltages due...
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Model and laboratory simulation of a induction motor for diagnostic purposes
PublikacjaStatistics say that bearings are this part of induction motors which is most susceptible to damage. The equipment employed for bearing diagnostics usually makes use of vibrations as the criterion for technical condition of the bearings. A faulty bearing results in additional motor vibrations. They are reflected in the harmonic content of stator currents. In certain operating conditions the current signal is the sole source of information...
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The basics of design and experimental tests of the commutation unit of a hydraulic satellite motor
Publikacjahe article presents an analytical method to design the commutation unit in a hydraulic satellite motor. It is shown that the size of the holes feeding the working chambers and their location on the plates closing those chambers depends on the geometrical dimensions of the working mechanism. The overlap in the commutation unit depends on the rotational speed range. It is demonstrated that the geometrical dimensions of the commutation...
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The influence of frequency separation on imaging properties in DFEIT
PublikacjaW artykule przedstawiono wpływ wyboru składowych częstotliwościowych dla różnicowej tomografii impedancyjnej na wynik i własności obrazowania w dwuczęstotliwościowej różnicowej tomografii impedancyjnej.A Dual Frequency EIT is an extension of a traditional EIT that uses two sinusoidal signals for imaging. Appropriate selection of signals' frequency allows to achieve reasonable contrast of imaged structure. It has already been shown...
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Indeksy demokracji i stan zaawansowania ich rozwoju dla pomiaru jakości demokracji na poziomie lokalnym - Democracy indices and current state of their advancement for measuring quality of democracy at a local level
PublikacjaJak mierzyć demokrację? Jak ocenić, czy jeden ustrój demokratyczny jest bardziej de-mokratyczny od innego i na jakiej podstawie to stwierdzić? Pomiary jakości demokracji na poziomie państw istnieją już od 1946 roku, a na ich podstawie powstawały indeksy demokracji jak np. Freedom House, Polity IV, czy też Varieties of Democracy. Poza poziomem państw jest zdecydowanie mniej narzędzi tego typu, a istniejące – jak np. Local Autonomy...
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O zastosowaniu metody prądów wirowych do technicznego pomiaru własności elektrycznych i magnetycznych metali = About application of eddy current method for technical measurement of electric and magnetic properties of metals
PublikacjaOpisano wyniki badań nad wykorzystaniem efektu prądów wirowych do badania własności elektrycznych i magnetycznych metali. Badania wykonano za pomocą sondy różnicowej. Wyniki pomiarów zależności częstotliwościowej wykonane dla modelowych materiałów porównano z wynikami modelowania metodą elementów skończonych.
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Electric shock hazard in circuits with variable-speed drives
PublikacjaThe conventional approach to electrical safety under fault condition in typical power systems considers earth fault currents of sinusoidal waveform and frequency of 50/60 Hz. However, in circuits with variable-speed drives, there is earth fault current flow with harmonics, and these harmonics influence the threshold of ventricular fibrillation. The paper presents earth fault current waveforms in circuits with variable-speed drives...
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A predictive estimation based control strategy for a quasi-resonant dc-link inverter
PublikacjaIn this paper the predictive estimation based control strategy for a quasi-resonant dc link inverter (PQRDCLI) is developed. Instead of direct measurement of dc link input inverter current – its estimation with one step prediction is applied. The PQRDCLI fed induction motor, controlled with a predictive current estimation stabilized inverter output voltage slopes independently of load. Moreover, reduction of overvoltage spikes...
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Recent Advances in Loop Heat Pipes with Flat Evaporator
PublikacjaThe focus of this review is to present the current advances in Loop Heat Pipes (LHP) with flat evaporators, which address the current challenges to the wide implementation of the technology. A recent advance in LHP is the design of flat-shaped evaporators, which is better suited to the geometry of discretely mounted electronics components (microprocessors) and therefore negate the need for an additional transfer surface (saddle)...
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Dynamics of fault arc traveling along busbars in high voltage switchboards = Dynamika łuku zwarciowego przemieszczającego się wzdłuż szyn rozdziel-nic wysokiego napięcia
PublikacjaThe paper presents the results of magnetic induction and electrodynamic force calculations acting on arc column during short-circuit in medium voltage air-insulated bus-bars. The gap between the bars was 120 mm and the prospective short-circuit currents ranged from 4 kA to 8 kA. The paper also shows the measurement results of average velocity fault arc depending on currents arc diameter and arc current was established and described....
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COMPARATIVE EVALUATION OF FERRITE SHIELDING DESIGNS IN INDUCTIVE POWER TRANSFER SYSTEMS
PublikacjaWireless power transfer technology is becoming widespread in last few years. In comparison to conventional solutions this technology can significantly increase maintainability and safety of charging systems. From the other side there are list of factors that limit efficiency of wireless systems. One of them is low coupling between coils caused by comparably high leakage inductance in comparison to regular transformer.
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Cross-Bonding of MV Cable Lines for Energy Losses Decrease
PublikacjaCurrently, almost all medium voltage cable lines (MV) operate with the return wires earthed at both ends of the cable. Such a way of operation causes that during normal states of operation as well as during disturbances, e.g. short-circuits, in the return wires induce currents whose values mainly depend on the currents flowing in the phase wires. These currents in normal operating states are a source of additional energy losses...
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The Method of reduction of aerodynamic forces generated in turbine blade seals
PublikacjaThe distibution of pressure in the seal gaps does not only affect the so called '' leakage losses'' and the turbine stage overall efficiency but also plays an important role in the generation of aerodynamic forces which may cause self-excited rotor vibrations. The paper describes a chamber seal applied for the reduction of the aerodynamic forces created in shroud seals. This kind of turbine seal was patented and tested.
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The extended version of restriction analysis approach for the examination of the ability of low-molecular-weight compounds to modify DNA in a cell-free system
PublikacjaOne of the primary requirements in toxicology is the assessment of ability of chemicals to induce DNA covalent modification. There are several well-established methods used for this purpose such as 32P-Postlabeling or HPLC-MS. However, all of these approaches have difficult to overcome limitations, which prevents their use in genotoxin screening. Here, we describe the simple protocol exploiting specificity of restriction enzymes...
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Double Fed Induction Machine Drives
PublikacjaContents of the Chapter 22:Machine model.Properties of the DFM.Steady state machine operation.Control rules and decoupled control.Decoupling based on MM machine model.Decoupling based on vector model.Decoupling based on rotor current equation.Overall control system.Control system based on MM model.Control system based on vector model.Estimation of variables.Calculation of the angle between stator and rotor.Remarks about digital...
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Implementation of power transformer controlled switching algorithm
PublikacjaThe article presents two new algorithms of controlled switching the power transformer. The main aim of the paper is to obtain formulas that determine the moments of closing of the circuit breaker poles. The study contains projects of control systems for both algorithms. Mathematical formulas for the time instants of the breaker poles closing were developed on the basis of electric circuit theory and magnetic circuit theory. The...
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Selection of C-Type Filters for Reactive Power Compensation and Filtration of Higher Harmonics Injected into the Transmission System by Arc Furnaces
PublikacjaThis article presents a method for selecting the elements of a C-type filter working with a conventional LC-type filter for compensating reactive power and filtering out higher harmonics generated by arc furnaces and ladle furnaces. The study was conducted in a steel mill supplied by a 110 kV transmission system, where higher harmonic currents and nonlinear loads were measured. A series of computer simulations were performed under...
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Multi-Transformer Flyback Converter for Supplying Isolated IGBT and MOSFET Drivers
PublikacjaA multi transformer flyback converter topology for supplying transistor drivers is presented. The topology presents some advantages over typical multi output single transformer, as reduction of effective leakage inductance, equal magnetic coupling between primary and secondary circuits and better isolation between outputs. Simulation study carried out in the LTSpice IV program and preliminary experimental results indicate high...
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Magnetic field gradient as the most useful signal for detection of flaws using MFL technique
PublikacjaThe magnetic flux leakage (MFL) technique is extensively used for detection of flaws as well as for evaluation of their dimensions in ferromagnetic materials. However, proper analysis of the MFL signal is hindered by the MFL sensor velocity causing distortions of this signal. Traditionally measured components of the MFL signal are particularly sensitive to the scanning velocity. In this paper, an another signal – the gradient of...
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Impulse Impedance Measurements of Lightning Protection Earthings
PublikacjaLightning protection earthing systems should be tested at currents with time parameters similar to those of lightnings. A method and definition of a measured value of impulse impedance are introduced. The impulse impedance was determined by a quotient of voltage drop on the tested earthing to a value of current in measure circuit. The usefulness of the impulse method for lightning protection evaluation is tested on radio base stations...
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EMI mitigation of GaN power inverter leg by local shielding techniques
PublikacjaThis paper presents local shielding techniques applied to a half-bridge inverter leg with the aim to reduce the common mode (CM) current noise at converter’s DC input. The research study is conducted for 650V Enhancement mode Gallium Nitride (GaN) power transistor switches. Main contributors of parasitic capacitances referred to the inverter-leg middle point node are identified. Then, shielding solutions are proposed to reduce...
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ANALIZA WPŁYWU NIEJEDNOCZESNOŚCI ZAMYKANIA BIEGUNÓW ŁĄCZNIKA NA PRĄDY ZAŁĄCZENIOWE TRANSFORMATORA W STANIE JAŁOWYM
PublikacjaW artykule przedstawiono wyniki obliczeń symulacyjnych prądów załączeniowych transformatora dla różnych sekwencji zamykania biegunów łącznika. Sekwencje różniły się kolejnością łączenia faz oraz czasami opóźnienia w zamykaniu biegunów. Rozważono także kilka wariantów stanu namagnesowania szczątkowego rdzenia. Na podstawie analizy wyników stwierdzono, że przy jednoczesnym zamykaniu biegunów łącznika, właściwy dobór chwili załączenia...
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Data-driven models for fault detection using kernel pca:a water distribution system case study
PublikacjaKernel Principal Component Analysis (KPCA), an example of machine learning, can be considered a non-linear extension of the PCA method. While various applications of KPCA are known, this paper explores the possibility to use it for building a data-driven model of a non-linear system-the water distribution system of the Chojnice town (Poland). This model is utilised for fault detection with the emphasis on water leakage detection....
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Isolation of the relative decrease in magnetic permeability contribution to reluctance of an open magnetic circuit based on stray field measurements
PublikacjaThe goal of the study was to evaluate a relative decrease in magnetic permeability in open magnetic circuits based on stray magnetic field measurements. The boundary element method was used to simulate magnetic circuits with variable geometry and variable magnetic permeability. The simulated magnetic circuits were rectangular or bone-shaped flat samples. Reluctance was increased in the middle of the samples resulting in leakage...
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Model matematyczny strat objętościowych ściskania oleju hydraulicznego w pompie wyporowej o zmiennej wydajności
PublikacjaCelem pracy było stworzenie możliwości oceny strat objętościowych wynikających ze ściskania oleju hydraulicznego w komorach roboczych wysokociśnieniowej pompy wyporowej o zmiennej wydajności na obrót wału. Straty objętościowe ściskania oleju muszą być określone jako funkcje tych samych parametrów, w zależności od których ocenione są straty objętościowe przecieków oleju w komorach, wynikające z jakości rozwiązania konstrukcyjnego...
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The accuracy of pulse rate estimation from the sequence of face images
PublikacjaThe goal of this paper is to analyze the accuracy of pulse rate estimation from the sequence of face images. Simulated and real signals were used to evaluate two pulse rate estimators; one for frequency domain and the second one for time domain using the autocorrelation function. The results show that the mean difference between the reference measurements and estimated pulse rate values are about 2bpm. In the analysis of short...
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Comparison of Mathematical Models of Torque Transmitted by Multi-disc Wet Clutch with Experimental Results
PublikacjaIn this article was described the methodology for the experimental study of flows in the prototype of a satellite hydraulic motor with a rotating body. The experimental tests of the motor were carried out at a low constant rotational speed in a wide range of pressure drop in this motor. The constant rotational speed of the motor was kept by a worm gear. Based on the test results, the leakage characteristics in the flat gaps of...
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Experimental Study of Flow Rate in Hydraulic Satellite Motor with the Rotating Case at a Low Constant Rotational Speed
PublikacjaIn this article was described the methodology for the experimental study of flows in the prototype of a satellite hydraulic motor with a rotating body. The experimental tests of the motor were carried out at a low constant rotational speed in a wide range of pressure drop in this motor. The constant rotational speed of the motor was kept by a worm gear. Based on the test results, the leakage characteristics in the flat gaps of...
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Structural Health Monitoring of Overhead Power Transmission Lines
PublikacjaStructural Health Monitoring (SHM) is a novel and continuously developing branch of science and technology that draws attention of scientists all over the world. It creates opportunities to detect, localize and identify structural damage of various types such as: line breakage, permissible sag, bolt loosening, fatigue cracking or insulator contamination. On the other hand the methods used to estimate the remaining operational...
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Detection and time/frequency analysis of electric fields in the ground
PublikacjaThis paper sets out to detect and characterize electric fields in the ground (such as stray current fields) using a tandem time/frequency method of signal analysis. Results were obtained from investigations performed in the presence of a generated electric field with controlled variable characteristics, and in the presence of an electric field generated by a tramline. The analysis of measurement registers was performed using Short‐Time...
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Directions and Prospects for the Development of the Electric Car Market in Selected ASEAN Countries
PublikacjaThe purpose of this article is to present the current situation and evaluate the opportuni‐ ties for the development of the electric car market in selected Southeast Asian countries in the con‐ text of the current situation in the rest of the world. Currently, the electric car market is at an ad‐ vanced stage of development in regions such as Western Europe, the USA, and China. It should be noted, however, that the number of electric...
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Facial data registration facility for biometric protection of electronic documents
PublikacjaIn modern world, information is crucial, and its leakage may lead to serious losses. Documents as the main medium of information must be therefore highly protected. Nowadays, the most common way of protecting data is using passwords, however it seems inconvenient to type complex passwords, when it is needed many times a day. For that reason a significant research has been conducted on biometric authentication...
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Application of Illuminating Modes concept in modal expansion of elliptical resonator
PublikacjaIn the paper an IlluminatingModes (IM) approach as an extension of Spectral Domain Approach (SDA) is presented. IM concept is applied to the case of open microstrip planar elliptical resonator. A modal expansion of currents induced in the structures during illuminating them by a single plane wave is the novelty of the method. As an example of application of the method, we present the results obtained by an examination of two resonators...
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The Application of Satellite Image Analysis in Oil Spill Detection
PublikacjaIn recent years, there has been an increasing use of satellite sensors to detect and track oil spills. The satellite bands, namely visible, short, medium infrared, and microwave radar bands, are used for this purpose. The use of satellite images is extremely valuable for oil spill analysis. With satellite images, we can identify the source of leakage and assess the extent of potential damage. However, it is not yet clear how to...