Very Small Dust Particles (VSDP’S) in Comet C/1996 B2 (Hyakutake)

2000 ◽  
pp. 365-367
Author(s):  
N. C. Wickramasinghe ◽  
F. Hoyle
Keyword(s):  
Dust Particles ◽  
Small Dust

VERY SMALL DUST PARTICLES (VSDP's) IN COMET C/1996 B2 (HYAKUTAKE)

2015 ◽  
pp. 397-400
Author(s):  
N.C. Wickramasinghe ◽  
F. Hoyle
Keyword(s):  
Dust Particles ◽  
Small Dust

scholarly journals 5.3 Modeling of the Orbital Evolution of Vaporizing Dust Particles Near the Sun

1976 ◽  
Vol 31 ◽  
pp. 434-436 ◽  
Author(s):  
Zdenek Sekanina
Keyword(s):  
Interplanetary Space ◽  
Solar Radiation Pressure ◽  
Orbital Evolution ◽  
Critical Distance ◽  
Dust Particles ◽  
Dynamical Effect ◽  
The Sun ◽  
Particle Collisions ◽  
Rate Of Evaporation ◽  
Small Dust

AbstractThe Poynting-Robertson (P-R) effect (Robertson, 1937, Wyatt and Whipple, 1950), assisted by a pseudo P-R effect due to the sputtering (Whipple, 1955, 1967), is known to cause small dust particles in interplanetary space to spiral toward the sun. Evaporation from the surface of such particles thus increases progressively with time and their size is being reduced accordingly. When the rate of evaporation is no longer negligibly low, it induces on the particle a measurable dynamical effect, which is associated with the implied variations in the magnitude of solar radiation pressure relative to solar attraction. By gradually reducing solar attraction, the particle evaporation tends to increase the orbit dimensions, thus acting against P-R. The P-R inward spiraling, far exceeding the dynamical effect from evaporation at larger heliocentric distances, slows gradually down as the particle approaches the sun, and virtually ceases when the critical distance is reached, where the two forces approximately balance each other. Then, typically, the perihelion distance stabilizes, while the eccentricity starts increasing very rapidly until the particle is swept out of the solar system. This, in brief, is the orbital evolution of a vaporizing particle in the absence of other potentially important but rather poorly known processes, such as particle collisions, rotational bursting, electric charging and interactions with the solar wind and with the interplanetary magnetic field.

Laser Measurements of Fly Ash Rebound Parameters for Use in Trajectory Calculations

1987 ◽  
Vol 109 (4) ◽  
pp. 535-540 ◽  
Author(s):  
W. Tabakoff ◽  
M. F. Malak
Keyword(s):  
Gas Flow ◽  
Initial Conditions ◽  
Incidence Angle ◽  
Equations Of Motion ◽  
Solid Particles ◽  
Dust Particles ◽  
Laser Doppler Velocimeter ◽  
Laser Measurements ◽  
Flow Through ◽  
Small Dust

This paper describes an experimental method used to find particle restitution coefficients. The equations that govern the motion of solid particles suspended by a compressible gas flow through a turbomachine depend on the restitution coefficients. Analysis of the data obtained by a laser-Doppler velocimeter (LDV) system of the collision phenomenon gives the restitution ratios as a function of the incidence angle. From these ratios, the particle velocity components after collision are computed and used as the initial conditions to the solution of the governing equations of motion for particle trajectories. The erosion of metals impacted by small dust particles can be calculated by knowing the restitution coefficients. The alloy used in this investigation was 410 stainless steel.

scholarly journals Dust arcs in the region of Jupiter’s Trojan asteroids

2018 ◽  
Vol 609 ◽  
pp. A57 ◽  
Author(s):  
Xiaodong Liu ◽  
Jürgen Schmidt
Keyword(s):  
Cross Section ◽  
Size Range ◽  
Dynamical Evolution ◽  
Particle Dynamics ◽  
Dust Particles ◽  
Azimuthal Direction ◽  
Number Density ◽  
Trojan Asteroids ◽  
Two Peaks ◽  
Small Dust

Aims. The surfaces of the Trojan asteroids are steadily bombarded by interplanetary micrometeoroids, which releases ejecta of small dust particles. These particles form the faint dust arcs that are associated with asteroid clouds. Here we analyze the particle dynamics and structure of the arc in the region of the L4 Trojan asteroids. Methods. We calculate the total cross section of the L4 Trojan asteroids and the production rate of dust particles. The motion of the particles is perturbed by a variety of forces. We simulate the dynamical evolution of the dust particles, and explore the overall features of the Trojan dust arc. Results. The simulations show that the arc is mainly composed of grains in the size range 4−10 microns. Compared to the L4 Trojan asteroids, the dust arc is distributed more widely in the azimuthal direction, extending to a range of [30, 120] degrees relative to Jupiter. The peak number density does not develop at L4. There exist two peaks that are azimuthally displaced from L4.

A Scientific Proof of the Existence of God

1993 ◽  
Vol 5 (4) ◽  
pp. 1-16
Author(s):  
William S. Hatcher
Keyword(s):  
Biological Evolution ◽  
Large Mass ◽  
Physical World ◽  
Dust Particles ◽  
Nuclear Forces ◽  
Modern Physics ◽  
High Degree ◽  
Scientific Argument ◽  
Degree Of Order ◽  
Small Dust

Of the various systems that we can actually observe in the physical world, some (e.g., the movement of small dust particles suspended in the air) appear to be perfectly random (or chaotic); whereas, others (e.g., the growth of leaved plants) exhibit a high degree of order and structure. Whenever scientists encounter a phenomenon or system that exhibits a significant evolution towards order, but without any observable reason for such movement, they suspect the cause to be the objective action of some unseen force (e.g., the unseen force of gravity that, in the presence of a large mass like the earth, causes the persistent downward movement of unsupported objects). Using this method, modern physics has now validated the existence of at least four basic forces (gravity, the strong and the weak nuclear forces, and electromagnetic force), and continues to examine the possibility that other, hitherto undetected, forces may exist. In 1921 ‘Abdu’l-Bahá presented a cogent scientific argument for the existence of an objective, unseen force as the only reasonable explanation for the phenomenon of biological evolution. In the years since ‘Abdu’l-Bahá’s proof was first published, the findings of science have tended to show that, indeed, the phenomenon of evolution represents a persistent movement from disorder towards order of the kind that strongly suggests the action of some unobservable force different from all other forces so far discovered. In this article, we present a somewhat detailed reformulation of ‘Abdu’l-Bahá’s argument using certain contemporary scientific terms that were not current at the time ‘Abdu’l-Bahá wrote.

Study of Tensile Properties of Recycled Polypropylene with Glass Fibers at Different Temperature

2017 ◽  
Vol 756 ◽  
pp. 11-18 ◽  
Author(s):  
Vojtech Senkerik ◽  
Michal Stanek ◽  
Martin Ovsik ◽  
Lenka Hylova
Keyword(s):  
Tensile Properties ◽  
Preparation Method ◽  
Glass Fibers ◽  
Dust Particles ◽  
Original Material ◽  
Recycled Polypropylene ◽  
Large Particles ◽  
Small Dust ◽  
Recycled Material ◽  
Reinforcing Filler

This research paper studies the influence of preparation method of recycled polymer material with glass fibers on the tensile properties of the final product. The recycled material was made from polypropylene, which originally contained 30 % of glass fibers. It was divided into fractions using size of the crushed particles. These fractions ranged from large particles, similar to the original material, to small dust particles. Measurements were performed at various temperatures. It was found that the mixture of dust particles showed a large decrease in measured properties. It is mainly due to shortening of the large glass fibers, so that it no longer fulfills its function as reinforcing filler. Conversely, mixture with larger particles did not show a significant decrease in properties compared to the original material.

scholarly journals Walker occupancy has an impact on changing airborne bacterial communities in an underground pedestrian space, as small-dust particles increased with raising both temperature and humidity

PLoS ONE ◽  
2017 ◽  
Vol 12 (9) ◽  
pp. e0184980 ◽  
Author(s):  
Torahiko Okubo ◽  
Takako Osaki ◽  
Eriko Nozaki ◽  
Akira Uemura ◽  
Kouhei Sakai ◽  
...  
Keyword(s):  
Bacterial Communities ◽  
Dust Particles ◽  
Temperature And Humidity ◽  
Pedestrian Space ◽  
Small Dust

scholarly journals APPLICATION OF ELECTRIC FILTERS FOR CLEANING COTTON FROM SMALL DUST PARTICLES

2021 ◽  
Vol 83 (2-3) ◽  
Author(s):  
Sherzod Sharipov ◽  
Farrukh Khudoynazarov ◽  
Rustam Goziyev ◽  
Bekhruz Khayitov ◽  
Rizoqul Navruzov
Keyword(s):  
Dust Particles ◽  
Small Dust
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