scholarly journals A Gauss Elimination Method for estimating locations of extrema in gridded data: Applications for Potential Field Data

2020 ◽  
Author(s):  
Dung Nguyen Kim ◽  
Dung Tran Tuan
Keyword(s):  
Gradient Method ◽  
Numerical Models ◽  
Traditional Approach ◽  
Dimensional Space ◽  
Gaussian Elimination ◽  
Accurate Determination ◽  
Quadratic Functions ◽  
Horizontal Gradient ◽  
Elimination Method ◽  
New Approach

Abstract. Extrema in gravity measurements can be used to locate geological structures of interest and the boundaries of such structures can be associated with the maxima in the gradients of the gravitational field strength. Finding the extrema of measured geophysical fields measured on the Earth's surface when the data is sparse is challenging. The inferred positions of such extrema are highly model dependent. Polynomial functions of two variables can be fitted to the data. Higher order polynomials typically give more accurate determination of the extrema, but the maximum order of the polynomial is limited by the number of data points. Difficulties are accentuated in the vicinity of boundaries of the existing data. The maximum horizontal gradient method has often been applied in this context. But in that particular construction, quadratic functions are developed in each dimension. Although the magnitudes of the extracted coefficients are obtained from three points related by their positions on orthogonal straight lines, off axis information should be included as well. The present paper introduces a modification of the maximum horizontal gradient method to overcome these difficulties. A Function f of the two variables x and y: f(x,y) = a1x2 + a2y2 + a3x2y2 + a4x2y + a5xy2 + a6xy + a7x + a8y + a9 is established by Gaussian elimination method base on a 3x3 neighborhood data grid. An extract creates a 4-dimensional space based on 4 specific cases of function f, including x = 0, y = 0, y = −x and y = x, they are four functions of one variable. The extreme points position are detected from these functions of one variable. To prove the proposed theoretical basis, as well as the built computer program, the paper presents two numerical models. The obtained results shown that the new approach has more maxima points than the traditional approach. Beside advantages of new approach, some disadvantages is also discussed in this paper. Moreover, we conclude with the application of our new approach to gravitational data in the East Vietnam Sea and demonstrate that we thereby disclose the existence of a gravity trench undetectable in the traditional method.

scholarly journals The Formation of a Cavity in a 3D Flux Rope

2013 ◽  
Vol 8 (S300) ◽  
pp. 147-150 ◽  
Author(s):  
Donald Schmit ◽  
Sarah Gibson
Keyword(s):  
Ad Hoc ◽  
Numerical Models ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Flux Rope ◽  
Multiple Structures ◽  
Field Lines ◽  
Hydrostatic Balance ◽  
Distinct Field ◽  
Three Dimensional Space

AbstractThere are currently no three dimensional numerical models which describe the magnetic and energetic formation of prominences self-consistently. Consequently, there has not been significant progress made in understanding the connection between the dense prominence plasma and the coronal cavity. We have taken an ad-hoc approach to understanding the energetic implications of the magnetic models of prominence structure. We extract one dimensional magnetic field lines from a 3D MHD model of a flux rope and solve for hydrostatic balance along these field lines incorporating field-aligned thermal conduction, uniform heating, and radiative losses. The 1D hydrostatic solutions for density and temperature are then mapped back into three dimensional space, which allows us to consider the projection of multiple structures. We find that the 3D flux rope is composed of several distinct field line types. A majority of the flux rope interior field lines are twisted but not dipped. These field lines are density-reduced relative to unsheared arcade field lines. We suggest the cavity may form along these short interior field lines which are surrounded by a sheath of dipped field lines. This geometric arrangement would create a cavity on top of a prominence, but the two structures would not share field lines or plasma.

A New Approach for Determining Joint Stiffness of Bolted Joints

2014 ◽  
Vol 670-671 ◽  
pp. 1041-1044 ◽  
Author(s):  
Xi Wang Wang ◽  
Xiao Yang Li ◽  
Lin Lin Zhang ◽  
Xiao Guang Wang
Keyword(s):  
Accurate Determination ◽  
Joint Stiffness ◽  
Fatigue Loading ◽  
Bolted Joints ◽  
Analytical Models ◽  
Bolted Connection ◽  
New Approach ◽  
Axisymmetric Model ◽  
Force Equilibrium

Joint member stiffness in a bolted connection directly influence the safety of a design in regard to both static and fatigue loading as well as in the prevention of separation in the connection. Thus, the accurate determination of the stiffness is of extreme importance to predict the behavior of bolted assemblies. In this paper, An analytical 3D axisymmetric model of bolted joints is proposed to obtain the joint stiffness of Bolted Joints. Considering many different analytical models have been proposed to calculate the joint stiffness, the expression based force equilibrium can be a easy way to choose the best expression for the joint stiffness as a judgment criteria.

A New Pattern of Old Fabric: Taʻlīm-i fārisī and the Grammatical Description of the Persian Language in the Ottoman Empire

2021 ◽  
Vol 27 (41) ◽  
pp. 31-48
Author(s):  
Munir Drkić ◽  
Ahmed Zildžić
Keyword(s):  
Ottoman Empire ◽  
19Th Century ◽  
Paradigm Shift ◽  
Traditional Approach ◽  
New Approach ◽  
Persian Language ◽  
European Languages ◽  
Language Students ◽  
The 19Th Century

This paper aims to examine the work entitled Taʻlīm-i fārisī in the context of the Ottoman tradition of the grammatical study of the Persian language. Taʻlīm-i fārisī, most likely penned by Kemal-pasha, is a short yet exceedingly significant primer for Persian language students dated in the middle of the 19th century. After a brief overview of the Persian grammar studies in the Ottoman Empire, the authors present the work and its author and conduct an analysis of the content of Taʻlīm-i fārisī. In terms of its underlying methodology, this work stands halfway between two principal tendencies: one is the traditional approach to studying the Persian language in the Ottoman Empire; another is a new approach developed under the influence of grammatical description of European languages. This paradigm shift in the Persian language's grammatical description within the Ottoman Empire is readily observable in the primer under review.

scholarly journals Aggregator of Demand Response for Renewable Integration and Customer Engagement: Strengths, Weaknesses, Opportunities, and Threats

Energies ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 2391 ◽  
Author(s):  
Kody Ponds ◽  
Ali Arefi ◽  
Ali Sayigh ◽  
Gerard Ledwich
Keyword(s):  
Demand Response ◽  
Electricity Market ◽  
Swot Analysis ◽  
Traditional Approach ◽  
Customer Engagement ◽  
Energy Integration ◽  
New Approach ◽  
Advantages And Disadvantages ◽  
Knowledge Based ◽  
Political Economic

The world is progressing towards a more advanced society where end-consumers have access to local renewable-based generation and advanced forms of information and technology. Hence, it is in a current state of transition between the traditional approach to power generation and distribution, where end-consumers of electricity have typically been inactive in their involvement with energy markets and a new approach that integrates their active participation. This new approach includes the use of distributed energy resources (DER) such as renewable-based generation and demand response (DR), which are being rapidly adopted by end-consumers where incentives are strong. This paper presents the role of the DR aggregator to effectively integrate DER technology as a new source of energy capacity into electricity networks using information communication technology and industry knowledge., Based on DR aggregators, this framework will efficiently facilitate renewable energy integration and customer engagement into the electricity market. To this aim, advantages and disadvantages of DR aggregators are discussed in this paper from political, economic, social, and technological (PEST) points of view. Based on this analysis, a strengths, weaknesses, opportunities, and threats (SWOT) analysis for a typical DR aggregator is presented.

A New Approach for Fatigue Damage Modeling of Subsurface-Initiated Spalling in Large Rolling Contacts

2016 ◽  
Vol 139 (1) ◽  
Author(s):  
Aditya A. Walvekar ◽  
Neil Paulson ◽  
Farshid Sadeghi ◽  
Nick Weinzapfel ◽  
Martin Correns ◽  
...  
Keyword(s):  
Fatigue Damage ◽  
Damage Mechanics ◽  
Numerical Models ◽  
Rolling Contact ◽  
Fe Model ◽  
Triangle Mesh ◽  
Computationally Efficient ◽  
New Approach ◽  
Rolling Contacts ◽  
Delaunay Triangle

Large bearings employed in wind turbine applications have half-contact widths that are usually greater than 1 mm. Previous numerical models developed to investigate rolling contact fatigue (RCF) require significant computational effort to study large rolling contacts. This work presents a new computationally efficient approach to investigate RCF life scatter and spall formation in large bearings. The modeling approach incorporates damage mechanics constitutive relations in the finite element (FE) model to capture fatigue damage. It utilizes Voronoi tessellation to account for variability occurring due to the randomness in the material microstructure. However, to make the model computationally efficient, a Delaunay triangle mesh was used in the FE model to compute stresses during a rolling contact pass. The stresses were then mapped onto the Voronoi domain to evaluate the fatigue damage that leads to the formation of surface spall. The Delaunay triangle mesh was dynamically refined around the damaged elements to capture the stress concentration accurately. The new approach was validated against previous numerical model for small rolling contacts. The scatter in the RCF lives and the progression of fatigue spalling for large bearings obtained from the model show good agreement with experimental results available in the open literature. The ratio of L10 lives for different sized bearings computed from the model correlates well with the formula derived from the basic life rating for radial roller bearing as per ISO 281. The model was then extended to study the effect of initial internal voids on RCF life. It was found that for the same initial void density, the L10 life decreases with the increase in the bearing size.

scholarly journals A new approach to understanding teachers’ classroom practices

2014 ◽  
Vol 7 ◽  
Author(s):  
Lyla Alsalim
Keyword(s):  
Education Reform ◽  
Teaching And Learning ◽  
Classroom Practices ◽  
Teacher Practices ◽  
Traditional Approach ◽  
Reform Initiatives ◽  
New Approach ◽  
Teachers Beliefs ◽  
Recent Reform

Teaching is generally considered a complex practice that involves the constant and dynamic interaction between the teacher, the students and the subject matter. One of the main goals of most education reform initiatives has been to change teachers’ classroom practices. Most recent reform curricula focus on highlighting teacher practices that promote and evoke students’ understanding alongside the changes in content (Tirosh & Graeber, 2003). Changes to a teacher’s role that are included in the education reform movement call for more research in order to understand and theorise teachers’ classroom practices. In this paper, I will present patterns-of-participation (PoP) as a promising framework that aims to understand the role of the teacher for emerging classroom practices. Instead of relying on a traditional approach to understanding classroom practices by analysing teachers’ beliefs, this framework applies a participatory approach to look for patterns in the participation of individual teachers in many social practices at the school and in the classroom. Some of these practices are directly related to the teaching and learning of mathematics while others are not. And some of them relate to communities that are not actually present in the classroom or at the school. PoP views teachers’ social interaction in a certain community as a piece which is influenced by other pieces of social interactions. In every interaction, the ‘pieces’ shape a ‘fluctuating pattern' that shows the shifting impact of different, previous practices and the dynamic relations between them (Skott, 2010; 2011; 2013).

A New Pattern of Old Fabric: Taʻlīm-i fārisī and the Grammatical Description of the Persian Language in the Ottoman Empire

2021 ◽  
Vol 27 (41) ◽  
pp. 31-48
Author(s):  
Munir Drkić ◽  
Ahmed Zildžić
Keyword(s):  
Ottoman Empire ◽  
19Th Century ◽  
Paradigm Shift ◽  
Traditional Approach ◽  
New Approach ◽  
Persian Language ◽  
European Languages ◽  
Language Students ◽  
The 19Th Century

This paper aims to examine the work entitled Taʻlīm-i fārisī in the context of the Ottoman tradition of the grammatical study of the Persian language. Taʻlīm-i fārisī, most likely penned by Kemal-pasha, is a short yet exceedingly significant primer for Persian language students dated in the middle of the 19th century. After a brief overview of the Persian grammar studies in the Ottoman Empire, the authors present the work and its author and conduct an analysis of the content of Taʻlīm-i fārisī. In terms of its underlying methodology, this work stands halfway between two principal tendencies: one is the traditional approach to studying the Persian language in the Ottoman Empire; another is a new approach developed under the influence of grammatical description of European languages. This paradigm shift in the Persian language's grammatical description within the Ottoman Empire is readily observable in the primer under review.

On the Exact Representation of the Boundary Surfaces of the Swept Volume of a Cylinder Undergoing Rational Bézier and B-Spline Motions

1999 ◽  
Author(s):  
J. Xia ◽  
Q. J. Ge
Keyword(s):  
Tool Path ◽  
Traditional Approach ◽  
Object Motion ◽  
Exact Representation ◽  
Tool Path Planning ◽  
New Approach ◽  
B Spline ◽  
Volume Analysis ◽  
Swept Volume ◽  
Boundary Surfaces

Abstract This paper develops methods for the exact analysis and representation of the swept volume of a circular cylinder undergoing rational Bézier and B-spline motions. Instead of following the traditional approach of analyzing the point trajectory of an object motion for swept volume analysis, this paper seeks to develop a new approach to swept volume analysis by studying the plane trajectory of a rational motion. It seeks to bring together recent work in swept volume analysis, plane representation of developable surfaces, as well as computer aided synthesis of freeform rational motions. The results have applications in design and approximation of freeforms surfaces as well as tool path planning for 5-axis machining of freeform surfaces.

Curvature, a mechanical link between the geometrical complexities of a fault: application to bends, kinks and rough faults

2020 ◽  
Vol 223 (1) ◽  
pp. 211-232
Author(s):  
Pierre Romanet ◽  
Dye SK Sato ◽  
Ryosuke Ando
Keyword(s):  
Numerical Models ◽  
Slip Distribution ◽  
Unified Framework ◽  
New Approach ◽  
Fault Surface ◽  
Earthquake Mechanics ◽  
Analytical Perspective ◽  
The Difference ◽  
Field Lines ◽  
New Interpretation

SUMMARY Many recent studies have tried to determine the influence of geometry of faults in earthquake mechanics. However, it still remains largely unknown, and it is explored mainly with numerical models. In this paper, we will try to understand how exactly does the geometry come into play in the mechanics of an earthquake from analytical perspective. We suggest a new interpretation of the effect of geometry on the stress on a fault, where the curvatures of the fault that multiply the slip play a major role. Starting from the representation theorem, which links the displacement in a medium to the slip distribution on its boundary, and assuming a 3-D, homogeneous, infinite medium, a regularized boundary-element equation can be obtained. Using this equation, it is possible to separate the influence of geometry, as expressed by the curvatures and torsions of the field lines of slip on the fault surface, which multiply the slip, from the effect of the gradient of slip. This allows us to shed new light on the mechanical effects of geometrical complexities on the fault surface, with the key parameters being the curvatures and torsions of the slip field lines. We have used this new approach to show that, in 2-D static in-plane problems, the shear traction along the fault is mainly controlled by the gradient of slip along the fault, while the normal traction is mainly controlled by the slip that multiplies the curvature along the fault. Finally, we applied this new approach to re-interpret the effect of roughness (why there is a need for a minimum lengthscale in linear elasticity, how to study mechanically the difference of roughness measurements with the direction of slip, scaling of slip distribution versus geometry), bends and kinks (what is the difference between the two, are they sometimes equivalent), as well as to explain further the false paradox between smooth-and-abrupt-bends. This unified framework allows us to improve greatly our understanding of the effect of fault geometry on the mechanics of earthquakes.

scholarly journals “GENIT” AS EFFECTIVE DESIGN OF LEARNING MEDIA

2018 ◽  
Vol 42 ◽  
pp. 00043
Author(s):  
Mardiki Supriadi
Keyword(s):  
Traditional Approach ◽  
Educational Communication ◽  
Higher Learning ◽  
Educational Goals ◽  
New Approach ◽  
Learning Content ◽  
Teaching Content ◽  
Media And Technology ◽  
The Impact ◽  
Positive Effect

There are two main approaches to using media in schools: students can learn "from" Media and technology, and they can learn "with" media and technology. The basis for The use of media and technology as a "tutor" in schools is "educational communication," that is the deliberate act of communicating content (teaching content) for students by assuming that they will learn something "from" this communication, so communication is not again free but controlled and conditioned for educational purposes. Findings on the impact of technologybased instruction in education can be concluded that technology as a tutor has a positive effect on learning, one of them is the student can complete a set of educational goals in less time than necessary in a traditional approach. However, these two approaches only make the task become easier but do not activate and facilitate them to think critical and higher learning. “Media Genit” uses a new approach as an approach that can optimize perspective-based cognitive processes, constructivism, which constitutes an environment in which the student as a designer thinks creative about content combined with real-world tasks, student learning content, enjoy the learning process, and recognize that they have created something that is valuable.

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