Density of various materials

With practice much may be learned from the shape of the sedimentation curves shown in Figure 17. Thus, a curve with a rapidly changing slope indicates a poly-dispersed sample, while a curve approaching a straight line indicates mono-dispersion. Two samples have approximately the same particle-size distribution when their slopes at corresponding times are the same. The curves are also valuable since they give a graphical comparison of the density. The relative densities of various materials sized in this manner are in accordance with the point of ordinate interception. 

The current density of various materials was determined as a function of the potential difference between the anodic and cathodic branches of the current potential curves in 0.9% NaCl with a stable redox system Fe (CN)6" 7Fe (CN) [1]. The saline solution containing this redox system had a resting potential closely resembling that of a tissue culture fluid which has a redox potential of 400 mV. Ti and its alloys Ta and Nb exhibit a better resistance than the stainless steel AISI 316L and a wrought CoNiCr alloy. The same ranking can be observed during the measurement of the polarization resistance of the different materials [1]. Breakdown potential measurements of various implant materials in... 

Table 4.8 Estimated Material Cost and Density of Various Materials Used...

Figure 4.19. Shock pressure versus density Hugoniot states for initially porous quartz. Density of starting material is indicated on various curves. Porous properties of stishovite are represented by curves with 1.75, 2.13, and 2.65 Mg/m, initial density, whereas coesitelike properties are represented by 0.2-0.8 Mg/m curves (after Simakov and Trunin (1990)).

Water in its supercritical state has fascinating properties as a reaction medium and behaves very differently from water under standard conditions [771]. The density of SC-H2O as well as its viscosity, dielectric constant and the solubility of various materials can be changed continuously between gas-like and liquid-like values by varying the pressure over a range of a few bars. At ordinary temperatures this is not possible. For instance, the dielectric constant of water at the critical temperature has a value similar to that of toluene. Under these conditions, apolar compounds such as alkanes may be completely miscible with sc-H2O which behaves almost like a non-aqueous fluid. 

The extensive layered sediments at the south pole, which contain water ice, will provide information on climatic variations. The subsurface sounding radar instrument SHARAD (Shallow Radar) on board the Mars Reconnaissance Orbiter carried out a detailed cartographic study of the subsurface at the Martian south pole. The data indicate that the sediments there have been subjected to considerable erosion (R. Seu et al 2007). The density of the material deposited at the Martian south pole was calculated by M. T. Zuber and co-workers by combining data from the gravitational field with those from various instruments on board the Mars Orbiter, they obtained a value of 1,200 kg/m3. This value corresponds to that calculated for water ice containing about 15% dust (Zuber et al 2007). 

Table 9.3 shows the measured detonation velocities and densities of various types of energetic explosive materials based on the data in Refs. [9-11]. The detonation velocity at the CJ point is computed by means of Eq. (9.7). The detonation velocity increases with increasing density, as does the heat of explosion. Ammonium ni-trate(AN) is an oxidizer-rich material and its adiabatic flame temperature is low compared with that of other materials. Thus, the detonation velocity is low and hence the detonation pressure at the CJ point is low compared with that of other energetic materials. However, when AN particles are mixed with a fuel component, the detonation velocity increases. On the other hand, when HMX or RDX is mixed with a fuel component, the detonation velocity decreases because HMX and RDX are stoichiometrically balanced materials and the incorporation of fuel components decreases their adiabatic flame temperatures. 

DENSITY SPECIFIC GRAVITY AND THEIR DETERMINATIONS (Densite in Fr Dichte in Ge Densita in Ital Densidad in Span Plotnost in Rus).Density abbr d) is the mass per unit volume of a substance at a defined temperature This physical property might serve for identification of various materials (including expls propints)... 

In this chapter, the basic definitions of the equivalent diameter for an individual particle of irregular shape and its corresponding particle sizing techniques are presented. Typical density functions characterizing the particle size distribution for polydispersed particle systems are introduced. Several formulae expressing the particle size averaging methods are given. Basic characteristics of various material properties are illustrated. 

The most often used unit to quantify the activity of any radioactive material is the curie (Ci). For most level detection applications, source strengths of 100 millicuries (mCi) or less are satisfactory. A 1 Ci source will produce a dose of 1 roentgen (r) at a receiver placed 1 m (3 ft) away from the source for 1 h. Radiation is attenuated when it penetrates liquids or solids, and the rate of attenuation is a function of the density of the material. The higher the density, the more attenuation the shielding material will provide. Figure 3.122 shows how various thicknesses of different materials will attenuate (reduction factor—NB) the intensity of radiation and result in different degrees of attenuation. 

Figure 9-23. Densities yielded at 5°C from solutions of various materials used to form density gradients 9 indicates the density of a 30% solution of Ludox.

The optimum firing temperature is usually determined experimentally shrinkage, porosity, strength and other properties important as regards application are determined on specimens exposed at various temperatures. Porosity is given by the equation P = 1 g jQy where q is density of the material free from pores and q is its bulk density (including the pores). In place of porosity, use is sometimes made of relative density, i.e, fraction of the actual density of the solid q Iq = — P. Porosity is also expressed in per cent (P x 100). 

There are two basic ways to express the mass concentration of dissolved species (solutes) in solution. The first is to state concentration in units of mass of solute in a unit volume of solution—the so-called w/v (weight/ volume) basis, The second is a w/w basis, that is, weight of solute in a given weight of solution. Both of these methods of expressing concentration are widely used in water chemistry. For example, the units mg/liter and ppm (parts per million) are, respectively, the w/v and w/w units most often used to express the concentration of various materials in waters and wastewaters. They can be interconverted if the density of the solution is known. 

The anodes are made of various materials and the choice is determined by the physical conditions, the electric field pattern, current densities, cost and anode corrosion. Anode current densities vary between 10 amperes per metre squared for silicon iron to more than 1000 amperes per metre squared for platinised and lead alloys. 

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