scholarly journals APPLICATIONS OF SPACE GEODESY METHODS IN ROMANIA

2020 ◽  
Vol 2 (1) ◽  
Author(s):  
Narvic Doru Mateciuc ◽  
Andrei Bălă
Keyword(s):  
Measurement Data ◽  
Global Scale ◽  
Complex Problem ◽  
Space Geodesy ◽  
Earthquake Forecasting ◽  
The Finite Element Method ◽  
Strong Earthquakes ◽  
New Energy ◽  
The University

The studies for Recent Crustal Movements by the aid of space geodesy techniques are integrated into the researches on the Earth’s crust dynamics, as a reflection of the complex geodynamic phenomena that occur in the crust and in the subcrustal lithosphere. In addition to the fundamental nature, the research in this field presents a practical characteristic, competing alongside geology and geophysics to the shaping of new energy sources or solid mineral substances, to the determination of the soil stability degree in inhabited areas or in those in which large industrial targets and utilities are intended to be placed in. The knowledge of movements affecting the Earth’s upper crust, movements that precede, accompany or follow the earthquakes, is also a topical issue. The paper presents some of the most important research projects developed in Romania, which were based on the measurement data obtained exclusively by space geodesy methods. There are presented some of the most significant results achieved in the framework of each research project together with the limitations imposed by the used acquisition technology. In chronological order are mentioned first GPS measurements in Romania, started in 1994, in a network centered on the Dealul Piscului observatory, followed by Romania's involvement in a regional geodynamic project, CERGOP and finally a major international project, CRC461, also continued after 2003 with the continuous help of the University of Delft (Nederland), a project that led to the development of an extended network of GPS permanent stations in Romania, all in operating status and whose results are a valuable support for the geodynamic studies. There are made brief references to the first application of the Finite Element Method in a GPS subnet from the Vrancea extended network together with some of the most important obtained results. The strong earthquakes with their catastrophic consequences, which have taken place in recent years on a global scale, similar to that of 4 March 1977 in Romania, have fully demonstrated the need for the knowledge of these types of crust movements in order to contribute, together with other methods, to solve the very complex problem of the earthquake forecasting.

scholarly journals ΙΣΤΟΡΙΑ, ΦΙΛΟΣΟΦΙΑ ΚΑΙ ΕΦΑΡΜΟΓΗ ΤΩΝ ΠΑΓΚΟΣΜΙΩΝ ΣΤΡΩΜΑΤΟΤΥΠΩΝ ΚΑΙ ΤΩΝ ΑΠΟΛΥΤΩΝ ΟΡΙΩΝ. ΠΡΟΣΦΑΤΕΣ ΑΝΑΟΕΩΡΗΣΕΙΣ ΤΗΣ ΓΕΩΛΟΓΙΚΗΣ ΧΡΟΝΙΚΗΣ ΚΛΙΜΑΚΑΣ

2006 ◽  
Vol 39 (1) ◽  
pp. 28
Author(s):  
Μ. Δ. Δερμιτζάκης
Keyword(s):  
Time Scale ◽  
Global Scale ◽  
Quality Of Data ◽  
Geological Time ◽  
Geological Time Scale ◽  
New Methods ◽  
Science Community ◽  
University Of Oslo ◽  
The University

In the last 150 years, the limits of the so called "formal" geochronological/ chronostratigraphical units were determined by several rock researchers using geohistorical events in several ways. The lack of standardisation made them useless for a global scale correlation. During the last two decades, the development of the field and laboratories techniques, the studies of radiogenic and stable isotopes, the improved evaluation of fossil files, the evaluation of paleomagnetic data and the application of cyclostratigraphy, improved the quality of data and contributed to the creation of the most upto-date International Chronostratigraphic Scale, including new subdivisions and determination of the boundaries of geological periods. The compiled New Geological Time Scale GTS 2004 integrates the most recent results of these new methods and was constructed by the International Union of Stratigraphy (ICS), in 2004, presiding F.M. Gradstein, from the University of Oslo, along with 38 other specialists. The new revised Geological Scale encompasses selected new methods that provide the most reliable information. The last Geological Time Scale incorporates important changes and is based on the application of the Global boundary Stratotype Section and Point (GSSP). Almost 50 GSSP have been defined up to now. Despite the enormous efforts for the construction of the most complete Geological Time Scale, a modified version needs the support and consent of the entire geological science community.

scholarly journals Determination of Transverse Shear Stiffness of Sandwich Panels with a Corrugated Core by Numerical Homogenization

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 1976
Author(s):  
Tomasz Garbowski ◽  
Tomasz Gajewski
Keyword(s):  
Transverse Shear ◽  
Shear Stiffness ◽  
The Finite Element Method ◽  
Homogenization Procedure ◽  
Plate Structures ◽  
Corrugated Board ◽  
Energy Equivalence ◽  
The Stability ◽  
Global Stiffness Matrix

Knowing the material properties of individual layers of the corrugated plate structures and the geometry of its cross-section, the effective material parameters of the equivalent plate can be calculated. This can be problematic, especially if the transverse shear stiffness is also necessary for the correct description of the equivalent plate performance. In this work, the method proposed by Biancolini is extended to include the possibility of determining, apart from the tensile and flexural stiffnesses, also the transverse shear stiffness of the homogenized corrugated board. The method is based on the strain energy equivalence between the full numerical 3D model of the corrugated board and its Reissner-Mindlin flat plate representation. Shell finite elements were used in this study to accurately reflect the geometry of the corrugated board. In the method presented here, the finite element method is only used to compose the initial global stiffness matrix, which is then condensed and directly used in the homogenization procedure. The stability of the proposed method was tested for different variants of the selected representative volume elements. The obtained results are consistent with other technique already presented in the literature.

A Simple Unconsolidated Undrained Triaxial Compression Test Emulator

2015 ◽  
Vol 771 ◽  
pp. 104-107
Author(s):  
Riska Ekawita ◽  
Hasbullah Nawir ◽  
Suprijadi ◽  
Khairurrijal
Keyword(s):  
Triaxial Compression ◽  
Measurement Data ◽  
Radial Strain ◽  
Compression Tests ◽  
Viscous Effects ◽  
Axial Pressure ◽  
Strain Stress ◽  
The University ◽  
And Storage ◽  
Triaxial Compression Tests

An unconsolidated undrained (UU) test is one type of triaxial compression tests based on the nature of loading and drainage conditions. In order to imitate the UU triaxial compression tests, a UU triaxial emulator with a graphical user interface (GUI) was developed. It has 5 deformation sensors (4 radial deformations and one vertical deformation) and one axial pressure sensor. In addition, other inputs of the emulator are the cell pressure, the height of sample, and the diameter of sample, which are provided by the user. The emulator also facilitates the analysis and storage of measurement data. Deformation data fed to the emulator were obtained from real measurements [H. Nawir, Viscous effects on yielding characteristics of sand in triaxial compression, Dissertation, Civil Eng. Dept., The University of Tokyo, 2002]. Using the measurement data, the stress vs radial strain, stress vs vertical strain, and Mohr-Coulomb circle curves were obtained and displayed by the emulator.

scholarly journals Remarks by Maria Flores

2018 ◽  
Vol 112 ◽  
pp. 79-82
Author(s):  
Maria Flores
Keyword(s):  
Human Rights ◽  
International Relations ◽  
International Law ◽  
Global Scale ◽  
International Court Of Justice ◽  
Public International Law ◽  
Court Of Justice ◽  
International Court ◽  
Small Department ◽  
The University

I first became involved with international law while I was at university. After graduating, I decided to teach public international law. As an undergraduate, I particularly enjoyed this branch of study. I was attracted to it because it helped me to understand the problems, challenges, and breakthroughs in the field of international relations on a global scale. Therefore, after facing a competitive entry process, I joined the international law department of the Universidad de la República. It was a small department, but the university had produced some well-known scholars like Eduardo Jiménez de Aréchaga, who became a judge at the International Court of Justice, and Hector Gross Espiell, who served as a judge at the Inter-American Court of Human Rights.

Calculation and Verification of Magnetic Field Parameters in Axial Active Magnetic Bearing

2014 ◽  
Vol 214 ◽  
pp. 143-150
Author(s):  
Piotr Graca
Keyword(s):  
Magnetic Field ◽  
Finite Element Method ◽  
Magnetic Force ◽  
Magnetic Bearing ◽  
Active Magnetic Bearing ◽  
Magnetic Flux Density ◽  
Two Dimensional ◽  
The Finite Element Method ◽  
Magnetic Field Computation

The paper presents numerical modeling of an Axial Active Magnetic Bearing (AAMB) based on two-dimensional (2D) magnetic field computation. The calculations, assisted by the Finite Element Method (FEM), have focused on the determination of the magnetic flux density and the magnetic force. Obtained magnetic field parameters were then measured and verified on a physical model.

An Analysis of Conventional and Self-Aligned four Terminal Resistor Structures for The Determination of The Contact Resistivity from End Resistance Measurements

1986 ◽  
Vol 71 ◽  
Author(s):  
I. Suni ◽  
M. Finetti ◽  
K. Grahn
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Computer Model ◽  
Contact Resistivity ◽  
Experimental Results ◽  
The Finite Element Method ◽  
Model Based ◽  
A Value ◽  
And Diffusion

AbstractA computer model based on the finite element method has been applied to evaluate the effect of the parasitic area between contact and diffusion edges on end resistance measurements in four terminal Kelvin resistor structures. The model is then applied to Al/Ti/n+ Si contacts and a value of contact resistivity of Qc = 1.8×10−7.Ωcm2 is derived. For comparison, the use of a self-aligned structure to avoid parasitic effects is presented and the first experimental results obtained on Al/Ti/n+Si and Al/CoSi2/n+Si contacts are shown and discussed.

Some Unexpected Results in the Stress Calculation Around Multiple Holes in an Isotropic Plate Under In-Plane-Loads

2014 ◽  
Author(s):  
Ghazi H. Asmar ◽  
Elie A. Chakar ◽  
Toni G. Jabbour
Keyword(s):  
Finite Element ◽  
Isotropic Plate ◽  
Potential Method ◽  
The Finite Element Method ◽  
Close Proximity ◽  
Complex Fourier Series ◽  
Circular Holes ◽  
Complex Potential Method ◽  
Multiple Holes

The Schwarz alternating method, along with Muskhelishvili’s complex potential method, is used to calculate the stresses around non-intersecting circular holes in an infinite isotropic plate subjected to in-plane loads at infinity. The holes may have any size and may be disposed in any manner in the plate, and the loading may be in any direction. Complex Fourier series, whose coefficients are calculated using numerical integration, are incorporated within a Mathematica program for the determination of the tangential stress around any of the holes. The stress values obtained are then compared to published results in the literature and to results obtained using the finite element method. It is found that part of the results generated by the authors do not agree with some of the published ones, specifically, those pertaining to the locations and magnitudes of certain maximum stresses occurring around the contour of holes in a plate containing two holes at close proximity to each other. This is despite the fact that the results from the present authors’ procedure have been verified several times by finite element calculations. The object of this paper is to present and discuss the results calculated using the authors’ method and to underline the discrepancy mentioned above.

scholarly journals Comparative Study of Optimization Algorithms for The Optimal Reservoir Operation

2018 ◽  
Vol 246 ◽  
pp. 01003
Author(s):  
Xinyuan Liu ◽  
Yonghui Zhu ◽  
Lingyun Li ◽  
Lu Chen
Keyword(s):  
Reservoir Operation ◽  
Optimization Problems ◽  
Optimization Algorithms ◽  
Complex Problem ◽  
Optimization Techniques ◽  
Decision Variables ◽  
Handling Methods ◽  
Optimality Algorithm ◽  
Parameter Values

Apart from traditional optimization techniques, e.g. progressive optimality algorithm (POA), modern intelligence algorithms, like genetic algorithms, differential evolution have been widely used to solve optimization problems. This paper deals with comparative analysis of POA, GA and DE and their applications in a reservoir operation problem. The results show that both GA and DES are feasible to reservoir operation optimization, but they display different features. GA and DE have many parameters and are difficult in determination of these parameter values. For simple problems with mall number of decision variables, GA and DE are better than POA when adopting appropriate parameter values and constraint handling methods. But for complex problem with large number of variables, POA combined with simplex method are much superior to GA and DE in time-assuming and quality of optimal solutions. This study helps to select proper optimization algorithms and parameter values in reservoir operation.

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