scholarly journals Italian Magnetic Network and magnetic reference fields at 2010.0

2013 ◽  
Vol 55 (6) ◽  
Author(s):  
Guido Dominici ◽  
Antonio Meloni ◽  
Angelo Di Ponzio ◽  
Massimo Miconi
Keyword(s):  
Magnetic Field ◽  
Magnetic Measurements ◽  
Second Order ◽  
Reduction Procedure ◽  
Average Spacing ◽  
First Order ◽  
Order Polynomial ◽  
Magnetic Network ◽  
Selection Of ◽  
Reference Fields

<p>The Istituto Nazionale di Geofisica e Vulcanologia (INGV) has systematically undertaken the task of making measurements of the Earth's magnetic field in Italy. By tradition and because of the elongated geometric shape of our peninsula and islands, in Italy, a grid of more than 110 points, called the first order repeat stations, with an average spacing around 55-60 km, is in operation. Over this grid the measurements are repeated regularly, every 5 years. A survey of 131 repeat stations of the Italian Magnetic Network (including 2 observatories, 11 stations in Albania, 3 stations in Corsica and 1 in Malta) was carried out between 2009 and 2010 with the main purpose of updating our magnetic cartography. We describe the characteristics of magnetic first and second order networks, the magnetic measurements and the data reduction procedure. In agreement with the recommendations of MagNetE Committee, we report new repeat station data measured and reduced at 2010.0. An analytical expression, a second order polynomial, in latitude and longitude for the field elements, was determined, and coefficients for 2010.0 and average secular variation over the period 2005-2010, were obtained. The new maps for Italy, for D, F, H and Z at the epoch 2010.0, are shown. A selection of stations from the Italian Magnetic Network, based on their low values of anomaly with respect to a 'normal' field, is also proposed for future surveys.</p>

scholarly journals Reversibility of the Magnetocaloric Effect in the Bean-Rodbell Model

2021 ◽  
Vol 7 (5) ◽  
pp. 60
Author(s):  
Luis M. Moreno-Ramírez ◽  
Victorino Franco
Keyword(s):  
Magnetic Field ◽  
Thermal Hysteresis ◽  
Entropy Change ◽  
Second Order ◽  
Zero Field ◽  
First Order ◽  
Magnetic Field Change ◽  
Magnetocaloric Materials ◽  
Moderate Magnetic Field ◽  
The Magnetic Field

The applicability of magnetocaloric materials is limited by irreversibility. In this work, we evaluate the reversible magnetocaloric response associated with magnetoelastic transitions in the framework of the Bean-Rodbell model. This model allows the description of both second- and first-order magnetoelastic transitions by the modification of the η parameter (η<1 for second-order and η>1 for first-order ones). The response is quantified via the Temperature-averaged Entropy Change (TEC), which has been shown to be an easy and effective figure of merit for magnetocaloric materials. A strong magnetic field dependence of TEC is found for first-order transitions, having a significant increase when the magnetic field is large enough to overcome the thermal hysteresis of the material observed at zero field. This field value, as well as the magnetic field evolution of the transition temperature, strongly depend on the atomic magnetic moment of the material. For a moderate magnetic field change of 2 T, first-order transitions with η≈1.3−1.8 have better TEC than those corresponding to stronger first-order transitions and even second-order ones.

Study on Fillet Stresses Distribution of Crankshaft of High-Duty Diesel Engine

2011 ◽  
Vol 52-54 ◽  
pp. 1364-1368
Author(s):  
Wen Li ◽  
Ri Dong Liao ◽  
Zheng Xing Zuo
Keyword(s):  
Diesel Engine ◽  
Second Order ◽  
First Order ◽  
Fourier Expansions ◽  
Order Polynomial ◽  
Polynomial Expansions ◽  
Regional Stresses

Stresses distribution in crankshaft fillet region are mainly discussed in this paper. FEM is used for calculating the stresses. With the analysis of the regional stresses distribution, we concludes that the stresses can be fitted by first order of Fourier expansions, while all the parameters in the expansions can be expressed as second order polynomial expansions.

scholarly journals Lie transforms and motion of a charged particle in a periodic magnetic field

1984 ◽  
Vol 7 (1) ◽  
pp. 159-169
Author(s):  
Sikha Bhattacharyya ◽  
R. K. Roy Choudhury
Keyword(s):  
Magnetic Field ◽  
Charged Particle ◽  
Averaging Method ◽  
Second Order ◽  
Lie Series ◽  
Periodic Magnetic Field ◽  
First Order ◽  
Order Solution ◽  
Lie Transforms ◽  
Spatially Periodic

We use the Lie series averaging method to obtain a complete second order solution for motion of a charged particle in a spatially periodic magnetic field. A comparison is made with the first order solution obtained previously by Coffey.

scholarly journals Основное состояние двухподрешеточного анизотропного ферромагнетика в магнитном поле

2021 ◽  
Vol 63 (8) ◽  
pp. 1090
Author(s):  
С.Н. Мартынов
Keyword(s):  
Magnetic Field ◽  
Phase Transition ◽  
Order Phase Transition ◽  
Ground State ◽  
Magnetic Measurements ◽  
Second Order ◽  
Magnetic Phases ◽  
Threshold Conditions ◽  
Anisotropic Interactions ◽  
Second Order Phase Transition

The ground state of a classical ferromagnet with the noncollinear single-ion anisotropy axes of the two sublattices and antisymmetric and anisotropic symmetric exchanges between the sublattices has been considered in a magnetic field applied in the hard magnetic directions of the crystal. The threshold conditions on the anisotropic interactions parameters determined the ground state among the three possible magnetic phases have been obtained. Depended on the type of the ground state and field direction the transition between the phases occurs as a phase transition first or second order. The value of the antisymmetric exchange above that the reorientation between two noncollinear phases is terminated by the second order phase transition depends on the angle between the local easy axes and the value of single-ion anisotropy. The field dependences of the magnetization and susceptibility have been calculated for the different ground states. The comparison with the results of the magnetic measurements in the highly anisotropic ferromagnet PbMnBO_4 has been made.

scholarly journals Euler-Bernoulli Beam Theory: First-Order Analysis, Second-Order Analysis, Stability, and Vibration Analysis Using the Finite Difference Method

2021 ◽  
Author(s):  
Valentin Fogang
Keyword(s):  
Finite Difference ◽  
Beam Theory ◽  
Second Order ◽  
Governing Equations ◽  
Deflection Curve ◽  
Order Analysis ◽  
First Order ◽  
Finite Difference Approximations ◽  
Order Polynomial ◽  
Euler Bernoulli Beam

This paper presents an approach to the Euler-Bernoulli beam theory (EBBT) using the finite difference method (FDM). The EBBT covers the case of small deflections, and shear deformations are not considered. The FDM is an approximate method for solving problems described with differential equations. The FDM does not involve solving differential equations; equations are formulated with values at selected points of the structure. Generally, the finite difference approximations are derived based on fourth-order polynomial hypothesis (FOPH) and second-order polynomial hypothesis (SOPH) for the deflection curve; the FOPH is made for the fourth and third derivative of the deflection curve while the SOPH is made for its second and first derivative. In addition, the boundary conditions and not the governing equations are applied at the beam&rsquo;s ends. In this paper, the FOPH was made for all of the derivatives of the deflection curve, and additional points were introduced at the beam&rsquo;s ends and positions of discontinuity (concentrated loads or moments, supports, hinges, springs, etc.). The introduction of additional points allowed us to apply the governing equations at the beam&rsquo;s ends and to satisfy the boundary and continuity conditions. Moreover, grid points with variable spacing were also considered, the grid being uniform within beam segments. First-order analysis, second-order analysis, and vibration analysis of structures were conducted with this model. Furthermore, tapered beams were analyzed (element stiffness matrix, second-order analysis). Finally, a direct time integration method (DTIM) was presented. The FDM-based DTIM enabled the analysis of forced vibration of structures, with damping taken into account. The results obtained in this paper showed good agreement with those of other studies, and the accuracy was increased through a grid refinement. Especially in the first-order analysis of uniform beams, the results were exact for uniformly distributed and concentrated loads regardless of the grid. Further research will be needed to investigate polynomial refinements (higher-order polynomials such as fifth-order, sixth-order&hellip;) of the deflection curve; the polynomial refinements aimed to increase the accuracy, whereby non-centered finite difference approximations at beam&rsquo;s ends and positions of discontinuity would be used.

scholarly journals Comparative Results of Regional and Residual Anomalies with the Upward Continuation, Moving Average, and Polynomial Methods for Magnetic Data

2020 ◽  
Vol 2 (2) ◽  
pp. 90-93
Author(s):  
Luvera Deva Intan Indrawati ◽  
Rina Dwi Indriana ◽  
Irham Nurwidyanto
Keyword(s):  
Moving Average ◽  
Continuation Method ◽  
Second Order ◽  
Magnetic Data ◽  
Third Order ◽  
First Order ◽  
Upward Continuation ◽  
Order Polynomial ◽  
Matlab Programming ◽  
Polynomial Methods

Geophysics programing of regional and residual anomaly separation on Magnetic data has been carried out with the results compared with the upward continuation method in the OasisMontaj software. Separation of anomalies with moving average and polynomial methods is processed using Matlab programming. The orders used in the polynomial method are first-order, second-order and third-order. Comparison is done by calculating the match value. The chosen matching method is autocorrelation. Correlation of residual magnetic anomalies resulting from upward continuation (Magpick) to moving averages, 1st-order polynomials, 2nd-order polynomials and 3rd-order polynomials. Correlation values obtained for the moving average method are 0.9604, first order polynomial 0.9072, 2nd order polynomial 0.9482 and third order polynomial 0.6057. The moving average and second order polynomial methods can be used as a substitute method if we do not use the upward continuation method.

scholarly journals Kirchhoff-Love Plate Theory: First-Order Analysis, Second-Order Analysis, Plate Buckling Analysis, and Vibration Analysis Using the Finite Difference Method

2021 ◽  
Author(s):  
Valentin Fogang
Keyword(s):  
Finite Difference ◽  
Vibration Analysis ◽  
Plate Theory ◽  
Second Order ◽  
Governing Equations ◽  
Order Analysis ◽  
First Order ◽  
Order Polynomial ◽  
The Finite Difference Method ◽  
Point Stencil

This paper presents an approach to the Kirchhoff-Love plate theory (KLPT) using the finite difference method (FDM). The KLPT covers the case of small deflections, and shear deformations are not considered. The FDM is an approximate method for solving problems described with differential equations. The FDM does not involve solving differential equations; equations are formulated with values at selected points of the structure. Generally in the case of KLPT, the finite difference approximations are derived based on the fourth-order polynomial hypothesis (FOPH) and second-order polynomial hypothesis (SOPH) for the deflection surface. The FOPH is made for the fourth and third derivative of the deflection surface while the SOPH is made for its second and first derivative; this leads to a 13-point stencil for the governing equation. In addition, the boundary conditions and not the governing equations are applied at the plate edges. In this paper, the FOPH was made for all of the derivatives of the deflection surface; this led to a 25-point stencil for the governing equation. Furthermore, additional nodes were introduced at plate edges and at positions of discontinuity (continuous supports/hinges, incorporated beams, stiffeners, brutal change of stiffness, etc.), the number of additional nodes corresponding to the number of boundary conditions at the node of interest. The introduction of additional nodes allowed us to apply the governing equations at the plate edges and to satisfy the boundary and continuity conditions. First-order analysis, second-order analysis, buckling analysis, and vibration analysis of plates were conducted with this model. Moreover, plates of varying thickness and plates with stiffeners were analyzed. Finally, a direct time integration method (DTIM) was presented. The FDM-based DTIM enabled the analysis of forced vibration of structures, with damping taken into account. In first-order, second-order, buckling, and vibration analyses of rectangular plates, the results obtained in this paper were in good agreement with those of well-established methods, and the accuracy was increased through a grid refinement.

scholarly journals First- and Second-Order Full-Differential in Edge Analysis of Images

2014 ◽  
Vol 2014 ◽  
pp. 1-5
Author(s):  
Dong-Mei Pu ◽  
Yu-Bo Yuan
Keyword(s):  
Control Parameter ◽  
Second Order ◽  
Canny Operator ◽  
First Order ◽  
Good Selection ◽  
Pascal Voc ◽  
Uniform Definition ◽  
The Difference ◽  
Basic Ideas ◽  
Selection Of

Two concepts of first- and second-order differential of images are presented to deal with the changes of pixels. These are the basic ideas in mathematics. We propose and reformulate them with a uniform definition framework. Based on our observation and analysis with the difference, we propose an algorithm to detect the edge from image. Experiments on Corel5K and PASCAL VOC 2007 are done to show the difference between the first order and the second order. After comparison with Canny operator and the proposed first-order differential, the main result is that the second-order differential has the better performance in analysis of changes of the context of images with good selection of control parameter.

scholarly journals Consistency of Term star: a Statistical Analysis of the Productive Types of System Relations with Related Terminological Units

2020 ◽  
pp. 87-99
Author(s):  
M. N. Latu ◽  
A. A. Levit
Keyword(s):  
Statistical Analysis ◽  
Scientific Knowledge ◽  
Second Order ◽  
Semantic Relations ◽  
Scientific Publications ◽  
Semantic Relationships ◽  
First Order ◽  
Selection Of

The article is devoted to the study of the term as a system unit in its interconnections with contiguous linguistic facts on the example of semantic relations existing in the term star in the field of scientific knowledge “astrophysics”. The study is based on an analysis of the systemic correlation of units in the field of astrophysics. The authors focus on terms representing various categories of concepts in accordance with the nature of the referents they represent. The most and least productive semantic relations are established and analyzed with related first-order terms presented in the definition and second-order terms, the relations with which are represented in the texts of scientific publications outside of the definitions. The categorical pertaining of related terms with which the term star has a systemic relationship is also determined in the study. Using a statistical analysis of a selection of terms in the field of “astrophysics”, we found that the most productive semantic relationships for them are relationships such as generic, attribution, and “part-whole”.

scholarly journals SELECTION OF THE MATHEMATICAL MODEL FOR THE USE OF ENROFLOXACIN IN CATS

2019 ◽  
Vol 7 (4) ◽  
pp. 294-299
Author(s):  
Galya Shivacheva ◽  
Miroslav Vasilev
Keyword(s):  
Differential Equation ◽  
Akaike Information Criterion ◽  
Order Differential Equation ◽  
Information Criterion ◽  
Research Process ◽  
Second Order ◽  
First Order ◽  
Second Order Differential Equation ◽  
The Mathematical Model ◽  
Selection Of

The process of changing the concentration of enrofloxacin in blood plasma in cats after single intravenous injection was identified by three mathematical models - algebraic and two models represented respectively by a first order differential equation and a second order differential equation. In order to select the best model of the three, the Akaike information criterion corrected is used. With the most identification parameters differs the model based on a second-order differential equation. The lowest value of the Akaike information criterion corrected was also obtained with it. This fact gives reason to choose it for the best model for describing the research process.

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