DENSITY AND DIMENSIONS

Mass is clearly defined in SI units and there should be no confusion with 

Density is defined as mass per unit volume, whereas relative density is the mass of the substance compared to the mass of an equal volume of a reference substance (usually water) and is, hence, dimensionless. Relative density used to be commonly known as specific gravity but this term is now deprecated and should not be used. 

In practice, the method of measurement often involves the determination of the relative density to water but the density of water is assumed to be 1 Mg/m. Furthermore, the determination is often made by observation of gravitational forces but for convenience the forces are expressed in mass units. 

If the rubber is less dense than water, a less dense liquid of known density could be substituted but it is more usual to attach a sinker to the test piece. The sinker can conveniently be a small piece of lead, but using an item like a paper clip to suspend the test piece leads to complications as it will only be partly submerged. The weight of the sinker in water must be measured and it is a common error among inexperienced technicians to make this weighing in air. 

The British equivalent to ISO 2781 is BS 903 Part Al2 which is identical to the international method. Rather surprisingly, ASTM does not appear to have a specific method for density at the present time. There is, however, a section on density in the standard on chemical analysis of rubber products, D2973, which briefly gives methods by pycnometer, hydrostatic weighing and a compressed volume densimeter. The weighing method does not mention the use of a sinker for densities less than 1. There is also a method for density of rubber chemicals, D1817)4, which uses the pycnometer method and, interestingly, specifies a vacuum pump to remove air before the measurement.. 

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At the end of the second stage there is a sharp increase in propagation velocity to about lOOOm/sec. Depending on exptl conditions, this low velocity detonation (LVD) can propagate over considerable distances, or it can go over into a normal detonation whose propagation velocity is determined by the density and dimensions of the PETN layer. It is possible to observe local ignitions ahead of the LVD front... 

Although surface defect sites are involved in the initiation of pores they do not determine the density and dimension of the pores in the bulk PS. The bulk morphology of PS is determined by the property of semiconductors and anodization conditions. However, under certain conditions, such as using surface patterning to generate initiation sites, the bulk PS morphology can be controlled to some extent. 

An alternate approach for estimating maximum allowable velocities has been presented by Fair (see reference given in footnote for preceding paragraph) which is based on data obtained with sieve-tray and other types of finite-stage columns and takes into account the effect of surface tension of the liquid in the column, the ratio of the liquid flow rate to the gas flow rate, gas and liquid densities, and dimensions and arrangement of the contactor. In this method, the basic equation for the maximum allowable vapor velocity, equiva-... 

On the sixtieth day (remote observation time), among control animals, in 50 cases out of 70, in the cornea center leukoma occurred of varying density and dimensions. At the same period, a slight wall in the center of the cornea of rabbits given CMS was observed in 7 cases out of 70 (8.5%). 

Swift heavy ion beams with extremely high LETs are used to degrade strongly polymer chains within tracks over a range of a few tens of micrometers. After irradiation, the top surface of bulk thermoplastics such as polyethyleneterephtalate, polycarbonate, polyvinylidene fluoride or polyimide materials as well as thin films made of the same material are subsequently etched by a wet chemical treatment that reveals pores of which the shape, surface density and dimensions can be controlled by choosing appropriate conditions. High aspect ratio cylindrical or conical traces of diameter ranging from a few nanometers to some... 

The protoplanet forming the Earth was probably a disperse system containing materials in three phases (Szadeczky-Kardoss, 1968). Particles with greater density and dimension were found in the central part of the system. At a greater radial... 

Mass, density, and dimensions have been grouped together largely for convenience, but there is an obvious connection between them in that density can be derived from a knowledge of dimensions and mass. They are also measurements used as essential parts of other physical tests. For example, density is used to calculate volume loss in an abrasion test, mass is an intrinsic factor in water absorption tests, and there are very few tests that do not in some way involve the measurement of dimensions. 

These nanofilters are reusable filters that have controlled porosity at the nanoscale and at the same time, can be formed into macroscopic structures with controlled geometric shapes, density, and dimensions. A carbonaceous nanofilter was fabricated by carbon nanofiber, in the best condition was used for MS2 virus removal. The results showed that at pressures of 8-11 bar the MS2 viruses were removed with a high efficiency by using the fabricated nanofilter. The results showed that the fabricated nanofilter... 

Table 2. RX-55-AE-5 sample mass, volume, density and dimensions...

With the advent of sophisticated simulation techniques, the physics of the flow-enhanced nucleation process at the molecular level are gradually being unraveled (see Chapter 6). The results of such investigations can serve to validate and/or improve continuum-level FIC models. Some of the most advanced of these are compared here in terms of the formulation of flow-enhanced nucleation kinetics. A description of flow-induced oriented structure formation and application to IM are discussed in Section 14.4.2 and Section 14.4.3, respectively. We focus on models that calculate the number density and dimensions of nuclei since this is necessary to predict morphological features beyond merely the degree of crystallization or the volume fraction of semicrystalline material. Therefore, approaches based on a (modified) Nakamura equation are left out of consideration. 

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