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Alternative approach for damping coefficient estimation in instrumented first-mode dominant steel frame buildings
PublikacjaAn alternative approach geared towards estimating damping coefficients in steel frame buildings is presented and assessed. The proposed methodology is conceptually intuitive and its implementation is straightforward. It arises from fundamental principles of structural dynamics and utilizes actual seismic recordings from instrumented buildings. The presented approach is most suitable for low- and mid-rise shear-type structures,...
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Highly Compact Dual-Band Frequency Selective Surface for Path-loss and Coverage Improvement in Millimeter-wave Advanced Wireless Applications
PublikacjaIn this work, a compact dual-band frequency selective surface (FSS) for path-loss and coverage improvement in advanced wireless communication is showcased. The proposed FSS is a single-layer design with stable and high performance at both 24 GHz and 38 GHz operating frequencies, respectively. The design is highly compact with two wide-band reflection coefficient responses having 49.5% (14.5 – 26.4 GHz) and 66.57% (35.8 – 39.8 GHz)...
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New insights into structural, optical, electrical and thermoelectric behavior of Na0.5Bi0.5TiO3 single crystals
PublikacjaThe single crystals of lead-free Na0.5Bi0.5TiO3 were grown using the Czochralski method. The energy gaps determined from X-ray photoelectron spectroscopy (XPS) and optical measurements were approximately 2.92 eV. The current-voltage characteristics, depolarization current, dc (σdc) and ac (σac) electrical conductivity, and Seebeck coefficient of the crystals were investigated. The frequency/temperature-dependent electrical properties...
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Numerically Efficient Miniaturization-Oriented Optimization of an Ultra-Wideband Spline-Parameterized Antenna
PublikacjaDesign of ultra-wideband radiators for modern handheld applications is a challenging task that involves not only selection of an appropriate topology, but also its tuning oriented towards balancing the electrical performance and size. In this work, a low-cost design of a compact, broadband, spline-parameterized monopole antenna has been considered. The framework used for the structure design implements trust-region-based methods,...
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Pressure effects on the superconductivity of the HfPd2Al Heusler compound: Experimental and theoretical study
PublikacjaPolycrystalline HfPd2Al has been synthesized using the arc-melting method and studied under ambient-pressure conditions by x-ray diffraction from room temperature up to 450 °C. High-pressure x-ray diffraction up to 23 GPa was also performed using Diacell-type membrane diamond anvil cells. The estimated linear thermal expansion coefficient was found to be α=1.40(3)×10−5K−1, and the bulk modulus derived from the fit to the third-order...
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The Dilemmas of Choosing a Suitable Technology for Low Energy and Passive Houses in the Context of their Overheating Issues
PublikacjaIn compliance with European Union directives, numerous countries are introducing increasingly stricter legal limits on the estimated energy consumption of newly designed residential buildings. However, the fact, that regulations and designers' efforts are focused on decreasing energy consumption (and consequently carbon dioxide emissions) only at the post-occupancy stage, may lead to a significant increase in the carbon footprint...
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ECHOES REDUCTION DURING DIGITAL DATA TRANSMISSION IN HYDROACOUSTIC CHANNEL – LABORATORY EXPERIMENT
PublikacjaThe possibility of using a hydroacoustic channel for digital data transmission is very limited. This is due to the effect of multipath propagation of the emitted acoustic wave and the damping of the mechanical wave in this medium, which increase with frequency. The first of these phenomena results in inter-symbol interference disturbances in data transmission systems, including even hundreds of symbols. Due to the number of reflections...
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On Alternative Approaches to Design of Corporate Feeds for Low-Sidelobe Microstrip Linear Arrays
PublikacjaTwo design approaches, illustrated by simulations and measurements, aiming at a systematic computer-aided design of printed circuit feeds for low-sidelobe microstrip antenna arrays are described. The novelty of these approaches resides in identification of the optimal feed architectures with subsequent simulation-based optimization of the feed and array aperture dimensions. In this work, we consider microstrip corporate feeds realizing...
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Study of pH and temperature effect on lipophilicity of catechol-containing antioxidants by reversed phase liquid chromatography
PublikacjaLipophilicity of selected antioxidant phytochemicals, including flavonoids, phenolic acids and xanthonoids, was determined by reversed phase high performance liquid chromatography with UV detection (RP-HPLC-UV). The analyses run at different temperature and pH conditions in isocratic mode suggested that lipophilicity as distribution coefficient (logD) between aqueous and organic phase decreases with increasing temperature. For...
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Performance analyses of helical coil heat exchangers. The effect of external coil surface modification on heat exchanger effectiveness
PublikacjaThe shell and coil heat exchangers are commonly used in heating, ventilation, nuclear industry, process plant, heat recovery and air conditioning systems. This type of recuperators benefits from simple construction, the low value of pressure drops and high heat transfer. In helical coil,centrifugal force is acting on the moving fluid due to the curvature of thetube results in the development. It has been long recognized that the...
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Determination of Selected Metals in Fruit Wines by Spectroscopic Techniques
PublikacjaThe determination of metals in different types of food and beverages samples has drawn significant attention due to several reasons with the most important one being the nutritional and toxic effects of these elements or their compounds. The knowledge of certain elements content in wines/fruit wines is of special interest due to their toxicity in case of excessive intake and also the effect they seem to have on the organoleptic...
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Heat transfer intensification by enlarged surface roughness in the plate heat exchanger
PublikacjaIn the paper an experimental analysis of passive heat transfer intensification technique employed in the case of the plate heat exchanger is presented. The passive intensification was obtained by a modification of the heat transfer surface. The roughness of surface was increased by a use of glass micro-beads. Single-phase convective heat transfer in the water-water system was studied. The experiment was accomplished in two stages....
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COMPARISON OF HEAT TRANSFER CHARACTERISTICS IN SURFACE COOLING WITH BOILING MICROJETS OF WATER, ETHANOL AND HFE7100
PublikacjaThe basis of microjet technology is to produce laminar jets which when impinging the surface have a very high kinetic energy at the stagnation point. Boundary layer is not formed in those conditions, while the area of film cooling has a very high turbulence resulting from a very high heat transfer coefficient. Applied technology of jet production can result with the size of jets ranging from 20 to 500μm in breadth and 20 to 100μm...
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Experimental comparison of hydrodynamic thrust bearings with different pad surface materials
PublikacjaBabbitt is the material most frequently used as the pad surface material for hydrodynamic bearings operating at usual operating conditions. It shows many advantages important for safe bearing operation, as for example: low friction coefficient, corrosion resistance, fair mechanical properties and outstanding conformability. On the other hand, it is not free from disadvantages, such as limited fatigue strength or limited resistance...
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Molecular hydrogen solvated in water – A computational study
PublikacjaThe aqueous hydrogen molecule is studied with molecular dynamics simulations at ambient temperature and pressure conditions, using a newly developed flexible and polarizable H2 molecule model. The design and implementation of this model, compatible with an existing flexible and polarizable force field for water, is presented in detail. The structure of the hydration layer suggests that first-shell water molecules accommodate the...
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Structure and properties of liquid Al–Cu alloys: Empirical potentials compared
PublikacjaWe report on the structure and mass transport properties of liquid Al–Cu alloys predicted by two recently-developed empirical many-body potentials: MEAM (Jelinek et al., 2012) and EAM-ADP (Apostol and Mishin, 2011), and by the well-known Gupta potential. Total and partial pair correlation functions, angular distribution functions, densities, coordination numbers and self-diffusion coefficients are compared with published experimental...
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Torque capacity of multidisc wet clutch with reference to friction occurrence on its spline connections
PublikacjaIn this article developed mathematical model that includes friction occurrence on spline connections is presented. The work also contains results of experimental research on torque capacity of multidisc wet clutch. These results are expressed as a function of contact pressure for different number of friction surfaces. Due to increased interest in research concerning multidisc wet clutches it is essential to determine impact of...
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Comparative Analysis of Developed Rainfall Intensity–Duration–Frequency Curves for Erbil with Other Iraqi Urban Areas
PublikacjaRainfall Intensity–Duration–Frequency (IDF) relationships are widely used in water infrastructure design and construction. IDF curves represent the relationship between rainfall intensity, duration, and frequency, and are obtained by analyzing observed data. These relationships are critical for the safe design of flood protection structures, storm sewers, culverts, bridges, etc. In this study, the IDF curves and empirical IDF formulas...
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Seismic damage diagnosis in adjacent steel and RC MRFs considering pounding effects through improved wavelet-based damage-sensitive feature
PublikacjaThis paper aims to propose complex Morlet (cmorfb-fc) wavelet-based refined damage-sensitive feature (rDSF) as a new and more precise damage indicator to diagnose seismic damages in adjacent steel and Reinforced Concrete (RC) Moment Resisting Frames (MRFs) assuming pounding conditions using acceleration responses. The considered structures include 6- and 9-story steel and 4- and 8-story RC benchmark MRFs that are assumed to have...
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Ground Tire Rubber Filled Flexible Polyurethane Foam—Effect of Waste Rubber Treatment on Composite Performance
PublikacjaThe application range of flexible polyurethane (PU) foams is comprehensive because of their versatility and flexibility in adjusting structure and performance. In addition to the investigations associated with further broadening of their potential properties, researchers are looking for new raw materials, beneficially originated from renewable resources or recycling. A great example of such a material is ground tire rubber (GTR)—the...
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Structural and physical characterization of NpPt2In7
PublikacjaA new neptunium intermetallic compound, NpPt2In7, has been synthesized in polycrystalline form and characterized by several macroscopic techniques. A Rietveld analysis of its powder x-ray diffraction pattern shows that NpPt2In7 crystallizes in a tetragonal lattice with I4/mmm symmetry and lattice parameters a = 4.58471(3) Å, c = 21.5065(3) Å. Magnetic susceptibility, electrical resistivity, Hall effect, and heat capacity measurements indicate...
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Density, sound velocity, viscosity, and refractive index of new morpholinium ionic liquids with amino acid-based anions: Effect of temperature, alkyl chain length, and anion
PublikacjaIn this work, room temperature synthesis of twenty new ionic liquids (ILs) based on the N-alkyl-N-methylmorpholinium ([Mor1,R], R = 2, 3, 4, 6, 8) cation and N-acetyl-L-amino acid anions (L-alaninate, L-valinate, L-leucinate, L-isoleucinate) was described. The synthesized ILs were characterized by various spectroscopic techniques and high-resolution mass spectrometry. Furthermore, density (ρ), sound velocity (v), viscosity (η)...
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Influence of soil anisotropic stiffness on the deformation induced by an open pit excavation.
PublikacjaIn this paper, the problem of deformation induced by an open pit excavation in anisotropic stiff soils is analysed by FE modelling. The presented research is focused on the influence of material model with anisotropic stiffness on the accuracy of deformation predictions as compared with the field measurements. A new hyperelastic-plastic model is applied to simulate anisotropic mechanical behaviour of stiff soils. It is capable...
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Investigation of use of hydrophilic/hydrophobic NADESs for selective extraction of As(III) and Sb(III) ions in vegetable samples: Air assisted liquid phase microextraction and chemometric optimization
PublikacjaIn this paper, a green, cost-effective sample preparation method based on air assisted liquid phase microextraction (AA-LPME) was developed for the simultaneous extraction of As(III) and Sb(III) ions from vegetable samples using hydrophilic/hydrophobic natural deep eutectic solvents (NADESs). Central composite design was used for the optimization of extraction factors including NADES volume, extraction cycle, pH, and curcumin concentration....
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Development of an orbital shaker-assisted fatty acid-based switchable solvent microextraction procedure for rapid and green extraction of amoxicillin from complex matrices: Central composite design
PublikacjaIn this study, a cheap, fast and simple orbital shaker-assisted fatty acid-based switchable solvent microextraction (OS-FASS-ME) procedure was developed for the extraction of amoxicillin (AMOX) in dairy products, pharmaceutical samples and wastewater prior to its spectrophotometric analysis. Fatty acid-based switchable solvents were investigated for extracting AMOX. The key factors of the OS-FASS-ME procedure were optimized using...
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Atomic-Scale Finite-Element Modeling of Elastic Mechanical Anisotropy in Finite-Sized Strained Phosphorene Nanoribbons
PublikacjaNanoribbons are crucial nanostructures due to their superior mechanical and electrical properties. This paper is devoted to hybrid studies of the elastic mechanical anisotropy of phosphorene nanoribbons whose edges connect the terminals of devices such as bridges. Fundamental mechanical properties, including Young’s modulus, Poisson’s ratio, and density, were estimated from first-principles calculations for 1-layer, 3-layer, and...
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Prediction of fracture toughness in fibre-reinforced concrete, mortar, and rocks using various Machine learning techniques
PublikacjaMachine Learning (ML) method is widely used in engineering applications such as fracture mechanics. In this study, twenty different ML algorithms were employed and compared for the prediction of the fracture toughness and fracture load in modes I, II, and mixed-mode (I-II) of various materials, including fibre-reinforced concrete, cement mortar, sandstone, white travertine, marble, and granite. A set of 401 specimens of “Brazilian...
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Correlation between Compressive Strength and Heat of Hydration of Cement Mortars with Siliceous Fly Ash
PublikacjaThis paper presents the results of calorimetric and strength tests of mortars with ordinary Portland cement and two substitution rates (10 and 20%) of cement by siliceous fly ash. The prepared samples were cured under isothermal conditions at four different temperatures: 23, 33, 43 and 53 °C. Heat of hydration was measured using an isothermal calorimeter dedicated to monitor the hydration process of cementitious composites such...
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Current Trends in Wick Structure Construction in Loop Heat Pipes Applications: A Review
PublikacjaThermal control systems have been introduced as an important part of electronic devices, enabling thermal management of their electronic components. Loop heat pipe (LHP) is a passive two-phase heat transfer device with significant potential for numerous applications, such as aerospace applications, high-power LEDs, and solar central receivers. Its advantages are high heat transfer capability, low thermal resistance, long-distance...
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Non-uniqueness of fracture parameter choice in simulations of concrete cracking at mesoscale level
PublikacjaIn the paper a non-uniqueness of fracture parameter choice in simulations of cracking process in plain concrete specimens at mesoscale level under monotonic static loading is analysed. The Finite Element Method is used, where cracks are defined in a discrete way using interface cohesive elements with nonlinear material law including softening. The concrete mesostructure (such as: cement matrix, air voids, aggregates, and Interfacial...
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Description of symmetrical prolate ellipsoid magnetic signature parameters-Be = 50 mT, I = 70 deg, z = 200 m, q = 100 deg, j = 45 deg, a =4 m, e = 4, mr = 100
Dane BadawczeThe Earth magnetic field (Fig.1): BE – total magnetic flux density, BEx – x component of the Earth magnetic flux density, BEy = 0 y component of the Earth magnetic flux density, BEz – z component of the Earth magnetic flux density, I – the inclination of the Earth magnetic field.
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Description of symmetrical prolate ellipsoid magnetic signature parameters-Be = 50 mT, I = 70 deg, z = 50 m, q = 80 deg, j = 45 deg, a =4 m, e = 4, mr = 100
Dane BadawczeThe Earth magnetic field (Fig.1): BE – total magnetic flux density, BEx – x component of the Earth magnetic flux density, BEy = 0 y component of the Earth magnetic flux density, BEz – z component of the Earth magnetic flux density, I – the inclination of the Earth magnetic field.
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Description of symmetrical prolate ellipsoid magnetic signature parameters-Be = 50 mT, I = 70 deg, z = 50 m, q = 80 deg, j = 45 deg, a =4 m, e = 8, mr = 100
Dane BadawczeThe Earth magnetic field (Fig.1): BE – total magnetic flux density, BEx – x component of the Earth magnetic flux density, BEy = 0 y component of the Earth magnetic flux density, BEz – z component of the Earth magnetic flux density, I – the inclination of the Earth magnetic field.
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Description of symmetrical prolate ellipsoid magnetic signature parameters-Be = 50 mT, I = 70 deg, z = 200 m, q = 80 deg, j = 45 deg, a =4 m, e = 4, mr = 100
Dane BadawczeThe Earth magnetic field (Fig.1): BE – total magnetic flux density, BEx – x component of the Earth magnetic flux density, BEy = 0 y component of the Earth magnetic flux density, BEz – z component of the Earth magnetic flux density, I – the inclination of the Earth magnetic field.
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Description of symmetrical prolate ellipsoid magnetic signature parameters-Be = 50 mT, I = 70 deg, z = 100 m, q = 90 deg, j = 135 deg, a =4 m, e = 1, mr = 100
Dane BadawczeThe Earth magnetic field (Fig.1): BE – total magnetic flux density, BEx – x component of the Earth magnetic flux density, BEy = 0 y component of the Earth magnetic flux density, BEz – z component of the Earth magnetic flux density, I – the inclination of the Earth magnetic field.
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Description of symmetrical prolate ellipsoid magnetic signature parameters-Be = 50 mT, I = 70 deg, z = 200 m, q = 90 deg, j = 45 deg, a =4 m, e = 4, mr = 100
Dane BadawczeThe Earth magnetic field (Fig.1): BE – total magnetic flux density, BEx – x component of the Earth magnetic flux density, BEy = 0 y component of the Earth magnetic flux density, BEz – z component of the Earth magnetic flux density, I – the inclination of the Earth magnetic field.
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Description of symmetrical prolate ellipsoid magnetic signature parameters-Be = 50 mT, I = 70 deg, z = 10 m, q = 90 deg, j = 45 deg, a =4 m, e = 8, mr = 100
Dane BadawczeThe Earth magnetic field (Fig.1): BE – total magnetic flux density, BEx – x component of the Earth magnetic flux density, BEy = 0 y component of the Earth magnetic flux density, BEz – z component of the Earth magnetic flux density, I – the inclination of the Earth magnetic field.
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Description of symmetrical prolate ellipsoid magnetic signature parameters- Be = 50 mT, I = 70 deg, z = 100 m, q = 80 deg, j = 45 deg, a =4 m, e = 4, mr = 100
Dane BadawczeThe Earth magnetic field (Fig.1): BE – total magnetic flux density, BEx – x component of the Earth magnetic flux density, BEy = 0 y component of the Earth magnetic flux density, BEz – z component of the Earth magnetic flux density, I – the inclination of the Earth magnetic field.
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Description of symmetrical prolate ellipsoid magnetic signature parameters-Be = 50 mT, I = 70 deg, z = 10 m, q = 100 deg, j = 45 deg, a =4 m, e = 4, mr = 100
Dane BadawczeThe Earth magnetic field (Fig.1): BE – total magnetic flux density, BEx – x component of the Earth magnetic flux density, BEy = 0 y component of the Earth magnetic flux density, BEz – z component of the Earth magnetic flux density, I – the inclination of the Earth magnetic field.
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Description of symmetrical prolate ellipsoid magnetic signature parameters-Be = 50 mT, I = 70 deg, z = 100 m, q = 90 deg, j = 45 deg, a =4 m, e = 8, mr = 100
Dane BadawczeThe Earth magnetic field (Fig.1): BE – total magnetic flux density, BEx – x component of the Earth magnetic flux density, BEy = 0 y component of the Earth magnetic flux density, BEz – z component of the Earth magnetic flux density, I – the inclination of the Earth magnetic field.
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Description of symmetrical prolate ellipsoid magnetic signature parameters-Be = 50 mT, I = 70 deg, z = 20 m, q = 90 deg, j = 45 deg, a =4 m, e = 4, mr = 100
Dane BadawczeThe Earth magnetic field (Fig.1): BE – total magnetic flux density, BEx – x component of the Earth magnetic flux density, BEy = 0 y component of the Earth magnetic flux density, BEz – z component of the Earth magnetic flux density, I – the inclination of the Earth magnetic field.
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Description of symmetrical prolate ellipsoid magnetic signature parameters-Be = 50 mT, I = 70 deg, z = 20 m, q = 90 deg, j = 45 deg, a =4 m, e = 8, mr = 100
Dane BadawczeThe Earth magnetic field (Fig.1): BE – total magnetic flux density, BEx – x component of the Earth magnetic flux density, BEy = 0 y component of the Earth magnetic flux density, BEz – z component of the Earth magnetic flux density, I – the inclination of the Earth magnetic field.
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Description of symmetrical prolate ellipsoid magnetic signature parameters-Be = 50 mT, I = 70 deg, z = 20 m, q = 100 deg, j = 45 deg, a =4 m, e = 8, mr = 100
Dane BadawczeThe Earth magnetic field (Fig.1): BE – total magnetic flux density, BEx – x component of the Earth magnetic flux density, BEy = 0 y component of the Earth magnetic flux density, BEz – z component of the Earth magnetic flux density, I – the inclination of the Earth magnetic field.
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Description of symmetrical prolate ellipsoid magnetic signature parameters-Be = 50 mT, I = 70 deg, z = 20 m, q = 80 deg, j = 45 deg, a =4 m, e = 8, mr = 100
Dane BadawczeThe Earth magnetic field (Fig.1): BE – total magnetic flux density, BEx – x component of the Earth magnetic flux density, BEy = 0 y component of the Earth magnetic flux density, BEz – z component of the Earth magnetic flux density, I – the inclination of the Earth magnetic field.
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Description of symmetrical prolate ellipsoid magnetic signature parameters-Be = 50 mT, I = 70 deg, z = 10 m, q = 100 deg, j = 45 deg, a =4 m, e = 8, mr = 100
Dane BadawczeThe Earth magnetic field (Fig.1): BE – total magnetic flux density, BEx – x component of the Earth magnetic flux density, BEy = 0 y component of the Earth magnetic flux density, BEz – z component of the Earth magnetic flux density, I – the inclination of the Earth magnetic field.
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Description of symmetrical prolate ellipsoid magnetic signature parameters-Be = 50 mT, I = 70 deg, z = 200 m, q = 90 deg, j = 45 deg, a =4 m, e = 1, mr = 100
Dane BadawczeThe Earth magnetic field (Fig.1): BE – total magnetic flux density, BEx – x component of the Earth magnetic flux density, BEy = 0 y component of the Earth magnetic flux density, BEz – z component of the Earth magnetic flux density, I – the inclination of the Earth magnetic field.
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Description of symmetrical prolate ellipsoid magnetic signature parameters-Be = 50 mT, I = 70 deg, z = 50 m, q = 100 deg, j = 45 deg, a =4 m, e = 8, mr = 100
Dane BadawczeThe Earth magnetic field (Fig.1): BE – total magnetic flux density, BEx – x component of the Earth magnetic flux density, BEy = 0 y component of the Earth magnetic flux density, BEz – z component of the Earth magnetic flux density, I – the inclination of the Earth magnetic field.
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Description of symmetrical prolate ellipsoid magnetic signature parameters-Be = 50 mT, I = 70 deg, z = 100 m, q = 80 deg, j = 45 deg, a =4 m, e = 8, mr = 100
Dane BadawczeThe Earth magnetic field (Fig.1): BE – total magnetic flux density, BEx – x component of the Earth magnetic flux density, BEy = 0 y component of the Earth magnetic flux density, BEz – z component of the Earth magnetic flux density, I – the inclination of the Earth magnetic field.
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Description of symmetrical prolate ellipsoid magnetic signature parameters-Be = 50 mT, I = 70 deg, z = 200 m, q = 90 deg, j = 45 deg, a =4 m, e = 8, mr = 100
Dane BadawczeThe Earth magnetic field (Fig.1): BE – total magnetic flux density, BEx – x component of the Earth magnetic flux density, BEy = 0 y component of the Earth magnetic flux density, BEz – z component of the Earth magnetic flux density, I – the inclination of the Earth magnetic field.
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Description of symmetrical prolate ellipsoid magnetic signature parameters-Be = 50 mT, I = 70 deg, z = 200 m, q = 80 deg, j = 45 deg, a =4 m, e = 8, mr = 100
Dane BadawczeThe Earth magnetic field (Fig.1): BE – total magnetic flux density, BEx – x component of the Earth magnetic flux density, BEy = 0 y component of the Earth magnetic flux density, BEz – z component of the Earth magnetic flux density, I – the inclination of the Earth magnetic field.