scholarly journals 8. Quadrantid Meteor Shower: Eleven Years of Radar Observations

1977 ◽  
Vol 39 ◽  
pp. 171-174
Author(s):  
B. A. McIntosh
Keyword(s):  
International Cooperation ◽  
Cross Section ◽  
Meteor Shower ◽  
Continuous Series ◽  
Meteor Stream ◽  
Radar Observations ◽  
Meteor Streams ◽  
The Cross

In studying the evolution of meteor streams from cometary debris it is desirable to know the distribution of particles both around the orbit and in the cross section perpendicular to the orbit. Earth-based observations are limited to a once-per-year sample and also limited by the position of the observer on earth as it crosses the meteor stream. A continuous series, 11 years, of records of the Quadrantid meteor shower illustrates the problems and the results that can be achieved. International cooperation would greatly assist such studies.

scholarly journals Activity of the New Filament in the Perseid Meteor Stream

1996 ◽  
Vol 150 ◽  
pp. 109-112 ◽  
Author(s):  
M. Šimek ◽  
P. Pecina
Keyword(s):  
Cross Section ◽  
Activity Level ◽  
Activity Profile ◽  
Meteor Stream ◽  
Radar Observations ◽  
Maximum Flux ◽  
Secondary Maximum ◽  
Activity Peak ◽  
Section Profile ◽  
Cross Section Profile

AbstractThe activity profile of the new filament in the Perseid meteor stream and its 1986-1994 levels were analyzed from Ondřejov radar observations. The filament was first detected in 1986 at its minimum activity level. Its maximum flux was observed in 1993. A secondary maximum appeared in the period 1988-1989. The cross-section profile of the new cloud shows an activity peak at L⊙ = 138°.87±0°.04 (equinox 1950.0).

The structure of meteor streams associated with Comet Halley: Eta Aquarids and Orionids

1974 ◽  
Vol 22 ◽  
pp. 309-311
Author(s):  
Anton Hajduk
Keyword(s):  
Density Distribution ◽  
Meteor Shower ◽  
Point Of View ◽  
Orbital Elements ◽  
Statistical Point ◽  
Radar Observations ◽  
Meteor Streams ◽  
Stream Structure ◽  
Comet Halley ◽  
Radar Meteor

The association of Comet Halley with the Orionid and Eta Aquarid meteor streams is not commonly accepted at present. Southworth (1961) has determined the differences in the orbital elements of the Orionid stream and Comet Halley on the basis of 19 photographic meteors and found them to be rather large.Extensive observational material obtained since the beginning of this century, including a homogeneous series of the radar observations, carried out at the Springhill Meteor Observatory during the periods of the Orionid meteor shower activity in 1957–1967 has been used by the author (Hajduk 1971) to study the stream structure and its association with Comet Halley from a statistical point of view.The present analysis is an extension of the paper mentioned, based mainly on the radar observations of the Eta Aquarid meteor shower carried out at the Springhill Observatory during the period 1958–67. The total number of 240,000 radar meteor echoes observed in 670 hours between May 1 and May 10 during each of the years previously cited was used in this investigation. The observed variations in the hourly rates of echoes of different duration enable us to study the density distribution and size distribution of meteoric particles along and across the stream.

scholarly journals On the Relationship Between Comet P/Machholz and the Quadrantid Meteor Stream

1992 ◽  
Vol 152 ◽  
pp. 325-327 ◽  
Author(s):  
R. Gonczi ◽  
H. Rickman ◽  
C. Froeschlé
Keyword(s):  
Three Dimensional ◽  
Extensive Study ◽  
Meteor Shower ◽  
Meteor Stream ◽  
Orbital Inclination ◽  
Meteor Streams ◽  
Protection Mechanisms ◽  
The Subject ◽  
The Relationship

The Quadrantid meteor shower has been recognized for more than 150 years. The dynamics of the corresponding stream is peculiar due to the high orbital inclination and, for some particles, the closeness of the 2/1 mean motion resonance with Jupiter. It has been the subject of many investigations relating to the structure of the stream and its nodal retrogression as well as its long-term history and its likely cometary origin. Thus Hamid and Youssef (1963) found that the jovian secular perturbations lead to very large changes in the inclination and perihelion distance of typical stream particles with a period around 4000 yrs. From a more extensive study by Williamset al.(1979) it was obvious that this period is not unique but may vary considerably between different particles. Related to this behaviour is also the investigation by Froeschlé and Scholl (1982) who performed an extensive study of three-dimensional orbits at the 2/1 resonance. The orbits remain confined in the resonance zone and are stable in Hill's sense. Close encounters with Jupiter are avoided through the action of three main protection mechanisms:σlibration around 0,ωlibration aroud 90°, ande–ωcoupling, although most orbits exhibit large variations in inclination and eccentricity. Investigating in more detail a Quadrantid-like meteor stream, Froeschlé and Scholl (1986) also found a nonuniform nodal retrogression and an unusual progression. This behaviour causes a formation of arcs which was not found for other meteor streams in resonance with Jupiter – however, almost never having large inclinations.

A New Approach to the Demonstration of Oxidase-Localization Using Tannic Acid Or Catechin

1973 ◽  
Vol 31 ◽  
pp. 698-699
Author(s):  
V. Mizuhira ◽  
Y. Futaesaku
Keyword(s):  
Cross Section ◽  
Tannic Acid ◽  
Elastic Fiber ◽  
The Other ◽  
New Approach ◽  
Tissue Block ◽  
Active Reaction ◽  
The Cross

Previously we reported that tannic acid is a very effective fixative for proteins including polypeptides. Especially, in the cross section of microtubules, thirteen submits in A-tubule and eleven in B-tubule could be observed very clearly. An elastic fiber could be demonstrated very clearly, as an electron opaque, homogeneous fiber. However, tannic acid did not penetrate into the deep portion of the tissue-block. So we tried Catechin. This shows almost the same chemical natures as that of proteins, as tannic acid. Moreover, we thought that catechin should have two active-reaction sites, one is phenol,and the other is catechole. Catechole site should react with osmium, to make Os- black. Phenol-site should react with peroxidase existing perhydroxide.

Energy Distribution in Electron Beams

1972 ◽  
Vol 30 ◽  
pp. 568-569
Author(s):  
Tamotsu Ohno
Keyword(s):  
Electron Beam ◽  
Energy Distribution ◽  
Cross Section ◽  
Integral Curve ◽  
Electron Beams ◽  
Electron Gun ◽  
Angular Divergence ◽  
Apparent Increase ◽  
Integral Width ◽  
The Cross

The energy distribution in an electron; beam from an electron gun provided with a biased Wehnelt cylinder was measured by a retarding potential analyser. All the measurements were carried out with a beam of small angular divergence (<3xl0-4 rad) to eliminate the apparent increase of energy width as pointed out by Ichinokawa.The cross section of the beam from a gun with a tungsten hairpin cathode varies as shown in Fig.1a with the bias voltage Vg. The central part of the beam was analysed. An example of the integral curve as well as the energy spectrum is shown in Fig.2. The integral width of the spectrum ΔEi varies with Vg as shown in Fig.1b The width ΔEi is smaller than the Maxwellian width near the cut-off. As |Vg| is decreased, ΔEi increases beyond the Maxwellian width, reaches a maximum and then decreases. Note that the cross section of the beam enlarges with decreasing |Vg|.

Research in the cross-section of community psychology and global climate change: A call for action

2009 ◽  
Author(s):  
Marci Culley ◽  
Holly Angelique ◽  
Courte Voorhees ◽  
Brian John Bishop ◽  
Peta Louise Dzidic ◽  
...  
Keyword(s):  
Climate Change ◽  
Cross Section ◽  
Global Climate Change ◽  
Community Psychology ◽  
Global Climate ◽  
The Cross

Experimental Studies Of Multilayer Glass Structures On Compression, Compression With Bending And Simple Bending

2019 ◽  
pp. 22-30
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Applied Load ◽  
Experimental Studies ◽  
Strength Properties ◽  
Research Topic ◽  
Normative Values ◽  
Laminated Glass ◽  
The Cross ◽  
Experimental Values

The work of multilayer glass structures for central and eccentric compression and bending are considered. The substantiation of the chosen research topic is made. The description and features of laminated glass for the structures investigated, their characteristics are presented. The analysis of the results obtained when testing for compression, compression with bending, simple bending of models of columns, beams, samples of laminated glass was made. Overview of the types and nature of destruction of the models are presented, diagrams of material operation are constructed, average values of the resistance of the cross-sections of samples are obtained, the table of destructive loads is generated. The need for development of a set of rules and guidelines for the design of glass structures, including laminated glass, for bearing elements, as well as standards for testing, rules for assessing the strength, stiffness, crack resistance and methods for determining the strength of control samples is emphasized. It is established that the strength properties of glass depend on the type of applied load and vary widely, and significantly lower than the corresponding normative values of the strength of heat-strengthened glass. The effect of the connecting polymeric material and manufacturing technology of laminated glass on the strength of the structure is also shown. The experimental values of the elastic modulus are different in different directions of the cross section and in the direction perpendicular to the glass layers are two times less than along the glass layers.

Seasonality in the Cross-Section of Stock Returns

CFA Digest ◽  
2008 ◽  
Vol 38 (3) ◽  
pp. 55-56
Author(s):  
Kathryn Dixon Jost
Keyword(s):  
Stock Returns ◽  
Cross Section ◽  
The Cross
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