Cellular plastics and rubbers. Determination of linear dimensions

2015 ◽  
Keyword(s):  
Linear Dimensions

scholarly journals Determination of the minimum drop height of the spherical grains in the solution of the treater

2020 ◽  
Vol 175 ◽  
pp. 01019
Author(s):  
Viktor Saitov ◽  
Vyacheslav Farafonov ◽  
Aleksey Saitov ◽  
Tatyana Malykh
Keyword(s):  
Surface Tension ◽  
Hydrodynamic Drag ◽  
Drop Height ◽  
Grain Production ◽  
Linear Dimensions ◽  
Minimum Height ◽  
Pea Seeds ◽  
Spherical Grains ◽  
Pea Seed

One of the main reserves for increasing grain production is the use for sowing high-quality seeds, purified from impurities and pathogens. One of the main ways to protect the seed from various diseases is dressing. The most effective way to protect seeds from disease is wet dressing with the simultaneous release of grain impurities. To develop a device for cleaning and dressing seeds by density using a wet method, an estimate was made of the minimum height of the fall of the grain needed to overcome the surface tension of the liquid. As objects of research, pea seeds were used, having a shape close to a spherical. Therefore, a spherical grains with a density ρz = (1.15-1.45)·103 kg/m3 and a diameter of 2rz = (3.5-10.9)·10-3 m was taken as a model of pea seed. We study the fall of individual spherical grains with minimal (2rzmin = 3.5·10-3 m) and maximum (2rzmax. = 10.9·10-3 m)) linear dimensions that have a density ρz = 1.15; 1.25; 1.35 and 1.45·103 kg/m3. Drop occurs on the surface of the water (ρzh = 1.0·103 kg/m3) and the aqueous solution of the etchant (ρzh = 1.03; 1.06; 1.09; 1.12 and 1.15·103 kg/m3), with Corresponding coefficients σ of surface tension (0.0727; 0.0755; 0.0771; 0.0786; 0.0801, 0.0816 N/m) and hydrodynamic drag coefficients c = 0.4 (0.5 for ρzh = 1.12·103 and 1.15·103 kg/m3). The process of dressing grain is considered at a temperature of 20 °C. It was established that the minimum drop height h to overcome the surface tension of the dressing solution with all spherical grains should be 15.5·10-3 m.

THE EQUATION OF MOTION OF A GEOPHONE ON THE SURFACE OF AN ELASTIC EARTH

Geophysics ◽  
1944 ◽  
Vol 9 (1) ◽  
pp. 29-35 ◽  
Author(s):  
Alfred Wolf
Keyword(s):  
Wave Length ◽  
Elastic Solid ◽  
Damping Force ◽  
High Frequencies ◽  
Elastic Earth ◽  
Linear Dimensions ◽  
The Earth ◽  
Restoring Forces ◽  
System Equations

The motion of a geophone case placed on the surface of an elastic earth does not follow faithfully the motion of the earth at high frequencies. In effect, a weight placed on the surface of an elastic solid constitutes a damped oscillating system. The elastic restoring forces are determined by the area of contact between the weight and the surface of the solid and by the elastic moduli of the solid. The damping force is due to emission of elastic waves by the oscillating weight. The motion of the solid also contributes to the inertia of the system. Equations are developed for these forces on the assumption that the wave length is long compared to the linear dimensions of the area of contact between the weight and the elastic solid. This leads to a determination of the frequency of oscillation and of the decrement of such a system.

XIII. Experiments to determine the value of the British association unit of resistance in absolute measure

1882 ◽  
Vol 173 ◽  
pp. 661-697 ◽  
Keyword(s):  
Relative Velocity ◽  
British Association ◽  
Great Weight ◽  
Electric Currents ◽  
Sliding Surfaces ◽  
General Plan ◽  
Linear Dimensions ◽  
Absolute Measure ◽  
New Apparatus

The present paper relates to the same subject as that entitled “On the Determination of the Ohm in Absolute Measure," communicated to the Society by Dr. Schuster and myself, and published in the Proceedings for April 12, 1881 —referred to in the sequel as the former paper. The title has been altered to bring it into agreement with the resolutions of the Paris Electrical Congress, who decided that the ohm was to mean in future the absolute unit (10 9 C. G. S.), and not, as has usually been the intention, the unit issued by the Committee of the British Association, called for brevity the B.A. unit. Much that was said in the former paper applies equally to the present experiments, and will not in general be repeated, except for correction or additional emphasis. The new apparatus (Plate 48) was constructed by Messrs. Elliott on the same general plan as that employed by the original Committee, the principal difference being an enlargement of the linear dimensions in the ratio of about 3 : 2. The frame by which the revolving parts are supported is provided with insulating pieces to prevent the formation of induced electric currents, and more space is allowed than before between the frame and those parts of the ring which most nearly approach it during the revolution. It is supported on three levelling screws, and is clamped by bolts and nuts to the stone table upon which it stands. The ring is firmly fastened by nuts to two gun-metal pieces which penetrate it at the ends of the vertical diameter, and which form the shaft on which it rotates. The lower end of the bottom piece is rounded, and bears upon a plate of agate, on which the weight of the revolving parts is taken. A little above this comes the driving pulley (9 inches in diameter), and above this again the screw and nut by which the divided card is held. The top piece is hollow, forming a tube with an aperture of 1¼ inches, and is held by a well-fitting brass collar attached to the upper part of the frame. On this bearing the force is very small, so that the considerable relative velocity of the sliding surfaces has no ill effect. Notwithstanding its great weight, the ring ran very lightly, and the principal resistance to be overcome was that due to setting air in motion.

The Determination of the Contact Angle of a Liquid Droplet on a Thin Fiber

1977 ◽  
Vol 47 (8) ◽  
pp. 561-562 ◽  
Author(s):  
B. J. Carroll
Keyword(s):  
Contact Angle ◽  
Liquid Droplet ◽  
Single Fiber ◽  
New Technique ◽  
Thin Fiber ◽  
Nondestructive Determination ◽  
Linear Dimensions ◽  
A New Technique ◽  
Textile Fabric

A new technique for the measurement of the contact angle of a liquid on a small-denier fiber is described. Using a photomicrographic technique, the contact angle is determined from three linear dimensions of a liquid droplet located on a single fiber, the angle being read off from tables. The contact angle so obtained is in favorable circumstances reproducible to 1 degree. The new technique thus affords virtually nondestructive determination of the contact angle for the material of a textile fabric.

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