Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Powder pressure-density

Density. The density of the drilling fluid is adjusted using powdered high density soHds or dissolved salts to provide a hydrostatic pressure against exposed formations in excess of the pressure of the formation fluids. In addition, the hydrostatic pressure of the mud column prevents coUapse of weak formations into the borehole. Fluid densities may range from that of air to >2500 kg/m (20.8 Ib/gal). Most drilling fluids have densities >1000 kg/m (8.33 lb/gal), the density of water. The hydrostatic pressure imposed by a column of drilling fluid is expressed as follows ... [Pg.175]

Fig. 6.7. The predicted, one-dimensional, mean-bulk temperatures versus location at various times are shown for a typical powder compact subjected to the same loading as in Fig. 6.5. It should be observed that the early, low pressure causes the largest increase in temperature due to the crush-up of the powder to densities approaching solid density. The "spike in the temperature shown on the profiles at the interfaces of the powder and copper is an artifact due to numerical instabilities (after Graham [87G03]). Fig. 6.7. The predicted, one-dimensional, mean-bulk temperatures versus location at various times are shown for a typical powder compact subjected to the same loading as in Fig. 6.5. It should be observed that the early, low pressure causes the largest increase in temperature due to the crush-up of the powder to densities approaching solid density. The "spike in the temperature shown on the profiles at the interfaces of the powder and copper is an artifact due to numerical instabilities (after Graham [87G03]).
Shock-synthesis experiments were carried out over a range of peak shock pressures and a range of mean-bulk temperatures. The shock conditions are summarized in Fig. 8.1, in which a marker is indicated at each pressure-temperature pair at which an experiment has been conducted with the Sandia shock-recovery system. In each case the driving explosive is indicated, as the initial incident pressure depends upon explosive. It should be observed that pressures were varied from 7.5 to 27 GPa with the use of different fixtures and different driving explosives. Mean-bulk temperatures were varied from 50 to 700 °C with the use of powder compact densities of from 35% to 65% of solid density. In furnace-synthesis experiments, reaction is incipient at about 550 °C. The melt temperatures of zinc oxide and hematite are >1800 and 1.565 °C, respectively. Under high pressure conditions, it is expected that the melt temperatures will substantially Increase. Thus, the shock conditions are not expected to result in reactant melting phenomena, but overlap the furnace synthesis conditions. [Pg.181]

Explained variation Bonding Index Heywood shape parameter Powder bed density Particle diameter Permanent deformation pressure... [Pg.309]

Black sulfide is a black amorphous powder or crystalline substance (beta form) cubic structure metastable at ordinary temperatures converts to red sulfide by sublimation at ordinary pressure density 7.73 g/cm melts at 583.5°C insoluble in water, alcohol and nitric acid soluble in aqua regia, alkalies, and solutions of alkali metal sulfides. [Pg.580]

Figure 7.16 Pressure-density relationship in the compaction of metallic powders. Reprinted, by permission, from Encyclopedia of Materials Science Engineering, Vol. 5, p. 3874. Copyright 1986 by Pergamon Press. Figure 7.16 Pressure-density relationship in the compaction of metallic powders. Reprinted, by permission, from Encyclopedia of Materials Science Engineering, Vol. 5, p. 3874. Copyright 1986 by Pergamon Press.
Under the actions of the pressure of about 8 GPa and the temperature between 1660 - 1700 °C on diamond powders, the density and shrinkage of the samples being sintered attains the maximum for 7 s and the further temperature... [Pg.459]

Pm—horizontal pressure at 6 = 0 S—roll gap AL—arc-length segments Va— material trapped in volume space described by arc-lengths Fg—compressed volume space described by arc-lengths and ye— respective powder bulk densities in volume spaces and Vg and K—a material property constant for a given moisture content, temperature, and time of compaction. [Pg.3163]

Apart from the above mentioned relationships (pressure-porosity, piessure-volume, pressure-density) several less common methods to quantify compactibility of pharmaceutical powders have been explored and can be found in the literature. These relationships are briefly summarized by Sonnergaard (40) as shown in Table 2. [Pg.503]

Pt, density of powder pi, initial apparent density of powder Pc, density of powder applied pressure Pa. K, a,h and c are constants. [Pg.2347]

Yan et al. (2001), studied how bulk density of instant nonfat milk, spray-dried coffee, and freeze-dried coffee was affected by HHP processing times, particle size, and water activity. The experimental curves for each powder in Figure 10 show that the powder bulk density increased as the pressure increased but remained constant after the pressure reached a critical value of 207 MPa for spray-dried coffee and 276 MPa for freeze-dried coffee at different water activities. The final compressed densities were not significantly different. When the pressure is higher than the critical value, there are no void spaces between the agglomerates or primary particles even the primary particles are crushed, leaving no open or closed pores within. Bear in mind, it is assumed that the compression mechanisms are the same as those in the confined uniaxial compression tests. [Pg.251]

Many investigators have suggested empirical equations to describe the pressure-density (or pressure-porosity) relationships during compression processes. About 20 equations have been listed for powder compression in powder ceramics (Macleod, 1983) and for other kinds of powders (Peleg,... [Pg.265]

Heckel introduced an equation for the densification phenomenon of a powder column following the first-order kinetics relating the powder relative density with compression pressure a. [Pg.267]

The basic laws of burning of systems element-sodium azide-halide and synthesis of final refractory powders are investigated. Once the optimal technological parameters of synthesis are found, the technological process of obtaining of powders nitrides, carbonitrides, and compositions on their basis in a mode SHS-Az [12] is developed. It was found that the most appreciable influence on quality of final powders render density of reactor loading, pressure of gaseous medium, ratio of components in system, and size of particles in initial components mixture. [Pg.243]

The pressure-density for powders in a compression test at low-pressure range can be described by the following equation (Barbosa-Canovas et al., 1987) ... [Pg.27]

Powder consolidation density and pore size distribution Firing heating rate and temperature Applied pressure Gaseous Atmosphere Characterization Measurements ... [Pg.426]

A model cyclone of diameter D = 0.2 m operating at an inlet velocity = 15 m/s at ambient conditions on a chalk powder of density 2700 kg/m , at low solids loading, is by testing found to have the grade-efficiency curve shown in Fig. 8.B.I. The cyclone pressure drop was found to be 950 Pa. [Pg.178]


See other pages where Powder pressure-density is mentioned: [Pg.186]    [Pg.1889]    [Pg.701]    [Pg.715]    [Pg.654]    [Pg.652]    [Pg.1648]    [Pg.1650]    [Pg.3159]    [Pg.498]    [Pg.2347]    [Pg.2349]    [Pg.338]    [Pg.243]    [Pg.5]    [Pg.233]    [Pg.265]    [Pg.2330]    [Pg.2332]    [Pg.1893]    [Pg.1895]    [Pg.105]    [Pg.107]    [Pg.86]    [Pg.160]    [Pg.165]    [Pg.6]    [Pg.1359]    [Pg.2767]   


SEARCH



Powder density

Pressurized density

© 2024 chempedia.info