scholarly journals V. On the theory of free stream lines

1890 ◽  
Vol 181 ◽  
pp. 389-431 ◽  
Keyword(s):  
Free Stream ◽  
Fluid Motion ◽  
Steady Motion ◽  
Two Dimensions ◽  
Mathematical Solution ◽  
The Subject ◽  
Negative Pressures ◽  
Stream Lines ◽  
Salient Edges

The attention of mathematicians was first called to the subject of the present paper by a memoir of Helmholtz’s in 1868, on “Discontinuous Fluid Motion.” In discussing the steady motion of liquids past salient edges of fixed obstacles, it is found that the assumptio of continuity of the motion leads to negative pressures in the liquid. Helmholtz showed, in the paper above-mentioned, that some cases of this kind could be solved by assuming a surface of discontinuity, on one side of which the liquid is at rest, and he gave a mathematical solution of one case where the motion is in two dimensions.

The Reflective Skill – Constructive-Prognostic Analysis in Methodological Context

2021 ◽  
Vol 30 (2) ◽  
pp. 134-148
Author(s):  
Natasha Tzanova ◽  
◽  
Nadezhda Raycheva ◽  
Isa Hadjiali ◽  
◽  
...  
Keyword(s):  
Learning Experience ◽  
Two Dimensions ◽  
Historical Aspect ◽  
Prognostic Analysis ◽  
Teachers And Students ◽  
Functional Part ◽  
Cognitive Experience ◽  
The Subject ◽  
The Individual ◽  
Reflective Skills

In historical aspect, the skill is among the key categories in the realm of human practice, which are often an object of different researches – psychological, pedagogical, and last but not least methodological. This is a fact, because the skill is a vital term for the description of productivity of learning experience at least in two dimensions – personally fundamental, guaranteeing its effective functioning in different situations and personally pragmatic, as a multi-level transformation of the cognitive experience, for the completion of certain social roles and the necessary qualities of the subject for this. The skill is a blend between those two dimensions of productivity both in higher education and in secondary school. The reflective skills are a structural and functional part of the transformation of the cognitive, affective, and psycho-motor experience and as such are included in the individual educational reality of the subject, and to a higher degree it defines it. This is the reason why the constructive-prognostic analysis of the reflective skill in the area of Methodology is pointing at the answer of the questions: What is this, what is its structure, how does it get integrated in the system of skills, how does it form and develop. The answers of those questions are basis of its methodological decoding in the process of training teachers and students in Biology. All of this describes the territory of the methodological context of analysing the reflective skill.

scholarly journals The Determinants of Charity Misconduct

2017 ◽  
Vol 47 (1) ◽  
pp. 107-125 ◽  
Author(s):  
Diarmuid McDonnell ◽  
Alasdair C. Rutherford
Keyword(s):  
Multivariate Analysis ◽  
United Kingdom ◽  
Two Dimensions ◽  
Regulatory Action ◽  
The Public ◽  
Administrative Dataset ◽  
The United Kingdom ◽  
The Subject ◽  
Public Scrutiny

Charities in the United Kingdom have been the subject of intense media, political, and public scrutiny in recent times; however, our understanding of the nature, extent, and determinants of charity misconduct is weak. Drawing upon a novel administrative dataset of 25,611 charities for the period 2006-2014 in Scotland, we develop models to predict two dimensions of charity misconduct: regulatory investigation and subsequent action. There have been 2,109 regulatory investigations of 1,566 Scottish charities over the study period, of which 31% resulted in regulatory action being taken. Complaints from members of the public are most likely to trigger an investigation, whereas the most common concerns relate to general governance and misappropriation of assets. Our multivariate analysis reveals a disconnect between the types of charities that are suspected of misconduct and those that are subject to subsequent regulatory action.

Preliminary Investigation of Mesh Stability for Linear Systems

1999 ◽  
Author(s):  
Pete Seiler ◽  
Aniruddha Pant ◽  
J. K. Hedrick
Keyword(s):  
Linear Systems ◽  
Mimo Systems ◽  
Preliminary Investigation ◽  
Two Dimensions ◽  
String Stability ◽  
Significant Research ◽  
Simple Class ◽  
The Subject ◽  
A Chain ◽  
The One

Abstract Damping of disturbances as they propagate through a chain of interconnected systems, termed string stability, has been the subject of significant research. In this paper, we investigate mesh stability, which is the two-dimensional extension of string stability. We review the key results used for string stability analysis and then generalize the conditions for MIMO systems. These results are then applied to a simple class of linear systems which form a mesh in two-dimensions. It is shown (as in the one-dimensional case) that communicating the velocity and acceleration of the lead vehicle to all subsystems is sufficient for mesh stability. This result is then verified by simulation.

Fluid Statics and Buoyancy

1997 ◽  
Author(s):  
David Jon Furbish
Keyword(s):  
Coordinate System ◽  
Fluid Motion ◽  
Steady Motion ◽  
Linear Acceleration ◽  
Vertical Position ◽  
Global Coordinate System ◽  
Fluid Density ◽  
Vertical Coordinate ◽  
Isothermal Fluid ◽  
Static Fluid

Fluid statics concerns the behavior of fluids that possess no linear acceleration within a global (Earth) coordinate system. This includes fluids at rest as well as fluids possessing steady motion such that no net forces exist. Such motions may include steady linear motion within the global coordinate system as well as rotation with constant angular velocity about a fixed vertical axis. In this latter case, centrifugal forces must be balanced by centripetal forces (which arise, for example, from a pressure gradient acting toward the axis of rotation). Moreover, we assert that no relative motion between adjacent fluid elements exists. Fluid motion, if present, is therefore like that of a rigid body. In addition, we neglect molecular motions that lead to mass transport by diffusion. Thus, the idea of a static fluid is a macroscopic one. The developments in this chapter clarify how pressure varies with coordinate position in a static fluid. Both compressible and incompressible fluids are treated. In the simplest case in which the density of a fluid is constant, we will see that pressure varies linearly with vertical position in the fluid according to the hydrostatic equation. In addition, we will consider the possibility that fluid density is not constant. Then, variations in density must be taken into account when computing the pressure at a given position in a fluid column; the pressure arising from the weight of the overlying fluid no longer varies linearly with depth. In the case of an isothermal fluid, whose temperature is constant throughout, any variation in density must arise purely from the compressible behavior of the fluid in response to variations in pressure. In the case where temperature varies with position, fluid density may vary with both pressure and temperature. We will in this regard consider the case of a thermally stratified fluid whose temperature varies only with the vertical coordinate direction. Because fluid statics requires treating how fluid temperature, pressure, and density are related, the developments below make use of thermodynamical principles developed in Chapter 4.

Jean Quigley, The grammar of autobiography: A developmental account. Mahwah, NJ: Lawrence Erlbaum Associates, 2000. Pp. xiv, 232. Hb $49.95.

2001 ◽  
Vol 30 (3) ◽  
pp. 490-493
Author(s):  
Stanton Wortham
Keyword(s):  
Language Development ◽  
Developmental Psychology ◽  
Two Dimensions ◽  
Narrative Discourse ◽  
The Self ◽  
Narrative Self ◽  
Functional Linguistics ◽  
The Subject ◽  
Autobiographical Narrative

In The grammar of autobiography, Jean Quigley makes a claim that one often hears nowadays: that the self is constructed in autobiographical narrative discourse. Two dimensions of the work distinguish her analysis of narrative self-construction from many other treatments of the subject. First, she offers a genuinely interdisciplinary account, drawing on functional linguistics, theoretical and developmental psychology, and accounts of language development. Second, she studies a particular category of linguistic forms – modals – as the key to narrative self-construction.

scholarly journals Two-dimensional oscillations in divergent jets of compressible fluid

1934 ◽  
Vol 145 (854) ◽  
pp. 52-71 ◽  
Keyword(s):  
Compressible Fluid ◽  
Radial Flow ◽  
Fluid Motion ◽  
Radial Distance ◽  
Two Dimensions ◽  
Common Point ◽  
Compressible Fluids ◽  
Fluid Density ◽  
Straight Lines ◽  
Steady Velocity

1. The problem of determining the possible modes of stationary oscillation for a compressible fluid, moving with a steady velocity which is not constant, usually presents great difficulties. One case which is to some extent amenable to analysis is that of uniform radial flow in two dimensions, where the undisturbed paths of the fluid particles are straight lines radiating from a common point or source. The term “source” is here used somewhat loosely, for in the solution which will be given it is found that the fluid density attains unreal values inside a certain circle having its centre at this common point. It is well known that in radial flow two systems of velocity are possible to a compressible fluid—namely, either (i) zero velocity at r = ∞, and an increasing but limited velocity as the radial distance from the source decreases ( i. e. , a modified “perfect fluid” motion); or (ii) the maximum possible velocity at infinity (corresponding with zero pressure and density), and a decreasing speed—also limited—as r decreases. This type of flow is peculiar to compressible fluids.

Random sequential packing in Euclidean spaces of dimensions three and four and a conjecture of Palásti

1982 ◽  
Vol 19 (02) ◽  
pp. 382-390 ◽  
Author(s):  
B. Edwin Blaisdell ◽  
Herbert Solomon
Keyword(s):  
Packing Density ◽  
Two Dimensions ◽  
One Dimension ◽  
Euclidean Spaces ◽  
Four Dimensions ◽  
Actual Density ◽  
The Subject

A conjecture of Palásti [11] that the limiting packing density β d in a space of dimension d equals β d where ß is the limiting packing density in one dimension continues to be studied, but with inconsistent results. Some recent correspondence in this journal [7], [8], [13], [14], [15], [16], [18], [19], [20] as well as some other papers indicate a lively interest in the subject. In a prior study [3], we demonstrated that the conjectured value in two dimensions was smaller than the actual density. Here we demonstrate that this is also so in three and four dimensions and that the discrepancy increases with dimension.

scholarly journals Positioning China Watching

China Report ◽  
2017 ◽  
Vol 54 (1) ◽  
pp. 118-136
Author(s):  
Chih-Yu Shih
Keyword(s):  
Hong Kong ◽  
Civil War ◽  
Subject Matter ◽  
Two Dimensions ◽  
Chinese People ◽  
Chinese Civil War ◽  
The Subject

This article divides China watching by the two dimensions of position and purpose. By position, the article asks if a narrator looks at China from an external or an internal perspective. By purpose, it asks if the narrative is to critically provide an evaluative perspective, to objectively represent an authentic China, or to practically discuss a life and identity strategy of Chinese people. Specifically, the complex sensibilities towards China among Taiwanese migrant scholars reify the genuine and yet often-unnoticed agency required to proceed with writing on China. With initially both the Chinese Civil War and later pro-independence politics in Taiwan poisoning relationships with China, the politically divided Taiwanese scholars enter a different environment in Hong Kong, which urges neither total confrontation nor complete loyalty in approaching China. How the Hong Kong circumstances have impacted upon the choices of these Taiwanese intellectuals in their presentation of the subject matter of China, in comparison with their other colleagues in Hong Kong, is the primary goal of the following discussion.

Analysis of Flow Induced Vibration Using the Vorticity Transport Equation

1993 ◽  
Vol 115 (3) ◽  
pp. 485-492 ◽  
Author(s):  
Jure Marn ◽  
Ivan Catton
Keyword(s):  
Parametric Analysis ◽  
Dynamic Instability ◽  
Equations Of Motion ◽  
Fluid Motion ◽  
Governing Equations ◽  
Flow Induced Vibration ◽  
The Subject ◽  
An Array Of Cylinders ◽  
Vorticity Transport ◽  
Square Array

Crossflow induced vibrations are the subject of this work. The analysis is two dimensional. The governing equations for fluid motion are solved using linearized perturbation theory and coupled with the equations of motion for cylinders to yield the threshold of dynamic instability for an array of cylinders. Parametric analysis is performed to determine the lowest instability threshold for a rotated square array and correlations are developed relating the dominant parameters. The results are compared with theoretical and experimental data for similar arrays and the discrepancies are discussed.

Small-scale magnetic fields in turbulence: Saffman's approximation revisited

1980 ◽  
Vol 99 (3) ◽  
pp. 481-493
Author(s):  
Ralph Baierlein
Keyword(s):  
Magnetic Field ◽  
Numerical Evaluation ◽  
Two Dimensions ◽  
Three Dimensions ◽  
Small Scale ◽  
Fluid Element ◽  
Relative Time ◽  
Fourier Decomposition ◽  
The Subject ◽  
The Magnetic Field

The subject is the small-scale structure of a magnetic field in a turbulent conducting fluid, ‘small scale’ meaning lengths much smaller than the characteristic dissipative length of the turbulence. Philip Saffman developed an approximation to describe this structure and its evolution in time. Its usefulness invites a closer examination of the approximation itself and an attempt to place sharper limits on the numerical parameters that appear in the approximate correlation functions, topics to which the present paper is addressed.A Lagrangian approach is taken, wherein one makes a Fourier decomposition of the magnetic field in a neighbourhood that follows a fluid element. If one construes the viscous-convective range narrowly, by ignoring magnetic dissipation entirely, then results for a magnetic field in two dimensions are consistent with Saffman's approximation, but in three dimensions no steady state could be found. Thus, in three dimensions, turbulent amplification seems to be more effective than Saffman's approximation implies. The cause seems to be a matter of geometry, not of correlation times or relative time scales.Strictly-outward spectral transfer is a characteristic of Saffman's approximation, and this may be an accurate description only when dissipation suppresses the contributions from inwardly directed spectral transfer. In the spectral region where dominance passes from convection to dissipation, one can generate expressions for the parameters that arise in Saffman's approximation. Their numerical evaluation by computer simulation may enable one to sharpen the limits that Saffman had already set for those parameters.

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