摘要:

1. In my second contribution I haveprovedmathematically that“if the fluidity, as usually calculated, is plotted against the stress at the wall, the curve is independent of the dimensions of the apparatus, irrespective of the law of flow of the liquid under test.”

ISSN:0148-6055    

DOI:10.1122/1.2116393

出版商:The Society of Rheology    

年代:1931

数据来源: AIP

摘要:

The capillary flow of fluid and plastic materials that do not obey Poiseuille's Law has been subjected of recent years to very intensive study, and many hypotheses advanced which attempt to characterize the resistance to deformation of such materials. There is, however, a possible type of resistance which does not appear to have been previously considered, and which it is the purpose of this paper to discuss: a resistance which is a function of the strain, or amount of deformation already experienced. While it is probable that such an effect, when it occurs, is small, the question is of importance in connection with structural studies (e. g., of colloids), which are the occasion of many investigations of plastic or pseudoplastic flow.

ISSN:0148-6055    

DOI:10.1122/1.2116394

出版商:The Society of Rheology    

年代:1931

数据来源: AIP

摘要:

The mathematical formulation of any theory for the deformation of matter consists essentially in the development of differential equations relating the resistance developed by deforming forces to the relative displacements of differential elements and the successive time derivatives of these displacements. Such general formulations have been carried out for the elastic theory and for the theory of viscous flow, which are based on simple linear relations between the stress components and the strain components and their first time derivatives, respectively. For more complicated theories such general formulations are somewhat academic, as the resulting equations can only be solved for cases of flow in which a high degree of symmetry obtains, so that the equations and the boundary conditions reduce to comparatively simple forms. It is therefore sufficient to formulate any theory in terms general enough to include the cases of interest for which solutions can be obtained.

ISSN:0148-6055    

DOI:10.1122/1.2116395

出版商:The Society of Rheology    

年代:1931

数据来源: AIP

摘要:

In order to obtain information about the conditions of flow in solutions which show anomalous viscosity, the distribution of velocity in a straight tube of circular cross section for one of these solutions was directly determined by the methods that are usual in hydrodynamics. From a reservoir,A(Figure 1), the liquid flowed through a capillary tube (Figure 2). At the end of this tube in a box,B, was a Pitot‐tube (6), by means of which the velocity head of the flowing liquid was measured. The driving pressure was measured at the points (1) and (2) with a U‐shaped manometer, The Pitot‐tube also was connected with one limb of a second manometer, the other limb communicating with a bore (3). As the mouth of the Pitot‐tube was in exactly the same plane as that of the capillary tube and the bore (3), the velocity head was read directly on the manometer, since the hydrostatic pressure is constant in every plane perpendicular to the axis of the tube.

ISSN:0148-6055    

DOI:10.1122/1.2116396

出版商:The Society of Rheology    

年代:1931

数据来源: AIP

摘要:

This is a method used in measuring the softening point of a bituminous material. In fact, it has been adopted as standard by the American Society for Testing Materials. Recently Walker has discussed this test and suggested a more convenient form of apparatus.

ISSN:0148-6055    

DOI:10.1122/1.2116397

出版商:The Society of Rheology    

年代:1931

数据来源: AIP

摘要:

It has been proved that in the flow of liquids the resistance to flow depends, first, upon the size of the individual particles of which the liquid is composed and, second, upon the spacing of the particles, this latter being dependent upon the conditions of temperature and pressure. As the size of the particles is increased and the Brownian motion of the particles becomes less and less, the above statement cannot be accepted as applicable without supporting evidence. However, if the laws of flow of materials like powdered coal, cement, etc., were known, there might be developed an improved method for obtaining the average particle size. The sizes of the particles and their method of spacing will presumably determine questions concerning rates of settling, caking together, and the seepage of both gases and liquids in or out of the materials. In a preliminary investigation, it seemed best to begin with dry sand and capillaries of known lengths and radii, using various temperatures.

ISSN:0148-6055    

DOI:10.1122/1.2116398

出版商:The Society of Rheology    

年代:1931

数据来源: AIP

ISSN:0148-6055    

DOI:10.1122/1.2116399

出版商:The Society of Rheology    

年代:1931

数据来源: AIP

摘要:

Measurements of viscosity are practically all relative, since viscometers are calibrated with a liquid whose viscosity is assumed to be known, but many different values of the viscosity of water are in use dependent upon the authority consulted, or the conditions of temperature and upon the corrections which are made in the reduction of the data, and quite as often as not the final results are expressed as specific viscosities of one kind or another. Bulletin No. 278 of the U. S. Bureau of Standards contained certain proposals. (1) It was proposed that all viscosities be expressed in absolute units even though the measurements be relative. (2) Since the viscosity of water at 20°C is close to 0.0100 c. g. s. units, it was proposed to adopt the viscosity (or fluidity) of water at this particular temperature for the fundamental rheological standard. (3) By making the one‐one hundredth part of the c. g. s. unit the practical unit of viscosity, and calling it the centipoise (cp) an advantage would be gained in that viscosities would all be specific. This would be perhaps most appreciated in studying the viscosity of electrolytic solutions, which are compared with the viscosity of pure water. (4) Different authorities were compared, the later corrections added, and an attempt made to secure the best value to be used as standard. Since the viscosity may be calculated by formula from values in the vicinity of 20°, these values were also not neglected in arriving at the most probable value, which was given as 1.005 cp.

ISSN:0148-6055    

DOI:10.1122/1.2116400

出版商:The Society of Rheology    

年代:1931

数据来源: AIP

ISSN:0148-6055    

DOI:10.1122/1.2116401

出版商:The Society of Rheology    

年代:1931

数据来源: AIP

ISSN:0148-6055    

DOI:10.1122/1.2116402

出版商:The Society of Rheology    

年代:1931

数据来源: AIP