Statistical Study of the Rotation Effect of Am Stars

1976 ◽  
Vol 32 ◽  
pp. 675-683
Author(s):  
Keiichi Kodaira
Keyword(s):  
Statistical Study ◽  
Rotation Velocity ◽  
General View ◽  
Slow Rotation ◽  
Rotation Effect

SummaryExcess of [m1] index of Am stars, relative to normal stars, is statistically found to be correlated with rotation velocity; the coefficient is estimated at ∆׀m1׀ /∆V(km/sec) ˜ - 0.0007 among Am stars. This result supports the general view that slow rotation is essential for Am phenomena.

Rotating massive stars in general relativity

1967 ◽  
Vol 296 (1445) ◽  
pp. 189-200 ◽  
Keyword(s):  
General Relativity ◽  
Stability Analysis ◽  
Simple Formula ◽  
Massive Star ◽  
Massive Stars ◽  
Rotation Velocity ◽  
Weak Field ◽  
Slow Rotation ◽  
Equilibrium Configurations ◽  
Schwarzschild Radius

Equilibrium models of uniformly rotating massive stars are investigated, using a weak field, slow rotation approximation, which is shown to be adequate for all cases of interest. The fate of radial perturbations about these equilibrium configurations is investigated using a linear­ized stability analysis to determine the oscillation frequency σ in a peturbation ∝ e iσ t . An eigenvalue equation for σ 2 is obtained which can be made self adjoint with respect to the spatial metric, and a variational principle to determine σ 2 is derived. Numerical determinations of σ 2 have been carried out for a variety of masses, radii and rotational velocities, and these results are incorporated in a simple formula that gives the dependence of σ 2 on these quantities. The condition for instability, σ 2 negative, is determined, and it is found that for large masses and maximum rotation velocity, so that when centrifugal force balances gravity at the surface, a massive star becomes unstable when its radius is 208 times the Schwarzschild radius 2 GM/c 2 .

scholarly journals Slow Rotation of Gas in the Halos of Edge-on Galaxies M82 and NGC 4631

1991 ◽  
Vol 144 ◽  
pp. 307-308
Author(s):  
Y. Sofue ◽  
N. Nakai ◽  
T. Handa ◽  
G. Golla ◽  
H.-P. Reuter ◽  
...  
Keyword(s):  
Central Region ◽  
Galactic Plane ◽  
Rotation Velocity ◽  
Molecular Gas ◽  
Slow Rotation ◽  
Halo Gas

The rotation velocity of molecular gas in the halos of M82 and NGC4631 decreases with the height from the galactic plane. The slower rotation of halo gas can be explained if the gas is supplied from the central region of the galaxies due to some ejection.

Identification of Venous Variants in the Pineal Region with 3D Preoperative Navigation. A Statistical Study on the Venous Anatomy in the Living

Skull Base ◽  
2009 ◽  
Vol 19 (01) ◽  
Author(s):  
Mario Giordano ◽  
Wolf Luedemann ◽  
Lennart Stieglitz ◽  
Karsten Wrede ◽  
Laura Columbano ◽  
...  
Keyword(s):  
Statistical Study ◽  
Pineal Region ◽  
Venous Anatomy

Linguistic Data Model for Natural Languages and Artificial Intelligence. Part 5. Introduction to Logic

Discourse ◽  
2020 ◽  
Vol 6 (3) ◽  
pp. 109-117
Author(s):  
O. M. Polyakov
Keyword(s):  
Artificial Intelligence ◽  
Mathematical Logic ◽  
Natural Language ◽  
Semantic Interpretation ◽  
General View ◽  
World Model ◽  
Semantic Approach ◽  
Natural Languages ◽  
The World ◽  
Linguistic Aspect

Introduction. The article continues the series of publications on the linguistics of relations (hereinafter R–linguistics) and is devoted to an introduction to the logic of natural language in relation to the approach considered in the series. The problem of natural language logic still remains relevant, since this logic differs significantly from traditional mathematical logic. Moreover, with the appearance of artificial intelligence systems, the importance of this problem only increases. The article analyzes logical problems that prevent the application of classical logic methods to natural languages. This is possible because R-linguistics forms the semantics of a language in the form of world model structures in which language sentences are interpreted.Methodology and sources. The results obtained in the previous parts of the series are used as research tools. To develop the necessary mathematical representations in the field of logic and semantics, the formulated concept of the interpretation operator is used.Results and discussion. The problems that arise when studying the logic of natural language in the framework of R–linguistics are analyzed. These issues are discussed in three aspects: the logical aspect itself; the linguistic aspect; the aspect of correlation with reality. A very General approach to language semantics is considered and semantic axioms of the language are formulated. The problems of the language and its logic related to the most General view of semantics are shown.Conclusion. It is shown that the application of mathematical logic, regardless of its type, to the study of natural language logic faces significant problems. This is a consequence of the inconsistency of existing approaches with the world model. But it is the coherence with the world model that allows us to build a new logical approach. Matching with the model means a semantic approach to logic. Even the most General view of semantics allows to formulate important results about the properties of languages that lack meaning. The simplest examples of semantic interpretation of traditional logic demonstrate its semantic problems (primarily related to negation).

A Statistical Study of Process Variables to Optimize a High Speed Curtain Coater: Part I

TAPPI Journal ◽  
2009 ◽  
Vol 8 (1) ◽  
pp. 20-26 ◽  
Author(s):  
PEEYUSH TRIPATHI ◽  
MARGARET JOYCE ◽  
PAUL D. FLEMING ◽  
MASAHIRO SUGIHARA
Keyword(s):  
Boundary Layer ◽  
Experimental Design ◽  
High Speed ◽  
Statistical Study ◽  
Process Variables ◽  
High Speeds ◽  
The Stability ◽  
Air Removal ◽  
Removal System

Using an experimental design approach, researchers altered process parameters and material prop-erties to stabilize the curtain of a pilot curtain coater at high speeds. Part I of this paper identifies the four significant variables that influence curtain stability. The boundary layer air removal system was critical to the stability of the curtain and base sheet roughness was found to be very important. A shear thinning coating rheology and higher curtain heights improved the curtain stability at high speeds. The sizing of the base sheet affected coverage and cur-tain stability because of its effect on base sheet wettability. The role of surfactant was inconclusive. Part II of this paper will report on further optimization of curtain stability with these four variables using a D-optimal partial-facto-rial design.

Abrasive wear of polymer/steel gear drives

2008 ◽  
Vol 4 (1) ◽  
pp. 1-26
Author(s):  
Gábor Kalácska
Keyword(s):  
Wear Resistance ◽  
Abrasive Wear ◽  
Material Selection ◽  
Solid Particles ◽  
Soil Types ◽  
General View ◽  
Modern Engineering ◽  
Clean Environment ◽  
Engineering Polymers ◽  
Plastic Gears

Research was performed on the friction, wear and efficiency of plastic gears made of modern engineering polymers and their composites both in a clean environment (adhesive sliding surfaces) and in an environment contaminated with solid particles and dust (abrasive), with no lubrication at all. The purpose is to give a general view about the results of abrasive wear tests including seven soil types as abrasive media. At the first stage of the research silicious sand was applied between the meshing gears and the wear of plastic and steel gears was evaluated and analyzed from the point of different material properties (elongation at break, hardness, yield stress, modulus of elasticity) and its combinations. The different correlations between the experienced wear and material features are also introduced. At the second stage of the project the abrasive sand was replaced with different physical soil types. The abrasive wear of gears is plotted in the function of soil types. The results highlight on the considerable role of physical soil types on abrasive wear resistance and the conclusions contain the detailed wear resistance. The results offer a new tribology database for the operation and maintenance of agricultural machines with the opportunity of a better material selection according to the dominant soil type. This can finally result longer lifetime and higher reliability of wearing plastic/steel parts.

General view of women in reproductive age about contraception in Hatay: a questionnaire study

2014 ◽  
Vol 2 (1) ◽  
pp. 9
Author(s):  
Raziye Keskin Kurt ◽  
Ayşe Güler ◽  
Ali Ulvi Hakverdi ◽  
Ayşe Neslin Akkoca ◽  
Kenan Serdar Dolapcıoğlu ◽  
...  
Keyword(s):  
Reproductive Age ◽  
Questionnaire Study ◽  
General View
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