Diamond Dust Research Articles

Development of smoke guide for the evaluation of white plumes.

A smoke guide for use with white plumes has been developed by suspending size-graded industrial diamond dust in transparent plastic blocks. The guide consists of a series of four blocks containing dusts with white light transmittances of 20, 40, 60, and 80 per cent and scattering characteristics similar to those of white (oil) plumes commonly used for training smoke inspectors. The luminances of experimental plumes and guides with like transmittances are compared when viewed under different illuminating and viewing conditions. Similar tests with a U. S. Public Health Service Black Smoke Guide are also described.

Spark Erosion of Diamond

A spark erosion method of shaping diamond is described. The problem of the diamond being non-conductive is overcome by the formation of a thin carbon layer on the diamond surface. This layer is continuously reformed as the erosion proceeded. The apparatus and methods discussed are of an elementary nature. They demonstrate that the technique is workable and can also be adapted to many unusual applications. The cutting rate was independent of orientation and imperfections in the diamond crystal. Furthermore, no diamond dust was needed to assist abrasion.

An examination of the cytotoxic effects of silica on macrophages.

Effects of silica, diamond dust, and carrageenan on mouse macrophages were studied by phase-contrast cine-micrography, electron microscopy, histochemical techniques for lysosomal enzymes and measurements of the release of lysosomal enzymes into the culture medium. All added materials were rapidly taken up into phagosomes, to which lysosomes became attached. In all cases lysosomal enzymes were discharged into the phagosomes to form secondary lysosomes. Within 24 hr most of the silica particles and enzyme had escaped from the secondary lysosomes and lysosomal enzymes were found in the culture media. Most macrophages were killed by this time. With nontoxic particles (diamond dust, aluminium-coated silica, or silica in the presence of the protective agent polyvinyl-pyridine-N-oxide, PVPNO) ingested particles and lysosomal enzymes were retained within the secondary lysosomes for a much longer time, and cytotoxic effects were considerably delayed or absent altogether. It is concluded that silica particles are toxic because they are efficiently taken up by macrophages and can then react relatively rapidly with the membranes surrounding the secondary lysosomes. The particles and lytic enzymes can then escape into the cytoplasm, producing general damage, and thence into the culture medium. It is suggested that hydrogen bonding of silicic acid with lipid and protein constituents of the membrane accounts for the induced permeability. Protective agents such as PVPNO are retamed in lysosomes and preferentially form hydrogen bonds with silicic acid. Carrageenan is demonstrable within macrophages by its metachromatic reaction. It brings about release of enzymes from secondary lysosomes, but much more slowly than does silica. Silica released from killed macrophages is as cytotoxic as the original preparation. It is suggested that repeated cycles of macrophage killing in vivo leads to the mobilization of fibroblasts and fibrogenesis characterizing the disease silicosis.

The Effect of Suspended Ice Crystals on Radiative Cooling

Two periods of very low (below −40C) surface temperature of Fairbanks, Alaska, were studied in detail as part of ice fog investigations during the 1961–1962 winter. The observed cooling rates from teh snow surface up to 3000 m were to large to be satisfactorily explained by advection and/or by radiative heat losses from the air and from the snow surface. The excess is shown to be due to radiation from ice crystals suspended in air. The ice crystals, formed by overall cooling of the air, act as heat sinks. It is proposed that heat flows from the air to the crystals and is radiated away. This process results in strong temperature gradients in the air immediately adjacent to the crystals. It may also account for the fact that humidity measurements show less than saturation values during occurrences of ice fog, light snowfall or “diamond dust” crystal displays. The air temperature values used in determining humidity pertain to ambient air between the ice crystals, whereas the air in contact with crystals has a lower temperature and is saturated with respect to ice.

Determination of Lead in Leaded Steels by X-Ray Spectroscopy

The determination of lead in leaded steel by x-ray spectroscopy is highly dependent on proper surface preparation because of the tendency toward smearing or removal of the lead. A metallographic preparation technique using diamond dust as the abrasive is shown to provide reproducible and accurate results even with appreciable changes in the particle size of the lead. This work is part of a cooperative program with the United States Steel Corporation in the preparation of a leaded-steel spectrochemical standard. Although certain inhomogeneities, both linear and radial, were observed by x-ray spectroscopy in the rods tested, suitable material has been selected for use as the National Bureau of Standards spectroscopic standard

A new technique for grinding thin sections of dental enamel

Abstract A section of tooth is first cut to a thickness of 1–1.5 mm. One face of the section is then ground flat on plate glass with Aloxite and water and polished with 6 μ diamond compound on a soft base followed by 0–0.5 μ diamond dust and water on pitch. The polished face is now stuck to a flat glass slide with Eastman Adhesive No. 910. The second face of the section is then ground down by hand with Aloxite in oil on plate glass to a thickness of about 10 μ and polished as before. Pitch softened with a few percent of turpentine, and considerable care, are needed for the final polish.

Surface Preparation of Solid Metallic Samples for X-Ray Spectrochemical Analysis

AbstractIn X-ray spectrochemical determinations, the surface preparation of metal samples is important since the emitted secondary radiation is absorbed except for that emerging from the immediate surface. Surface preparation also has been found to be a critical factor in eliminating or at least in minimizing the effects of certain metallurgical changes among or within samples on the X-ray determinations. For example, a change of particle size of an undissolved constituent, or a change in grain size, may markedly influence the X-ray analysis, depending on the surface preparation. A metallographic polishing technique, whereby the sample surfaces were finished with ¼μ diamond dust, was reported for the determination of lead in leaded steel (Kilday and Michaelis, in press). This investigation has been extended to other materials such as hypereutectic silicon-aluminum alloy and white-cast iron. A comparison is made of the effects of different surface preparations on X-ray determinations.

The effect of diamond dust alone and mixed with quartz on the lungs of rats.

Diamond, the hardest of all minerals, was classed as an inert material, similar to anthracite and corundum, by Gardner (1938) on the basis of intra venous injection experiments in rabbits. By intra peritoneal injection into mice Bovet (1952) produced collagenous nodules in places where much diamond dust was accumulated. But it took six months to one year for such nodules to form as against a few weeks for quartz of similar size. Schiller (1955) injected diamond dust intra peritoneally into mice, alone and combined with silicic acid in the form of aerosil . The diamond

Precise measurements of the density of mercury at 20°C I. Absolute displacement method

This paper gives an account of the absolute measurement of the density of mercury at 20° C in units of length and mass, the result of which is probably correct to one part in a million. The densities of four samples of mercury have been measured by finding the mass of mercury displaced by an accurately formed cube of known volume that just sinks in mercury. The cube is of tungsten carbide sintered with cobalt, its sides are 8.9 cm long, it weighs 9.7 kg in air and 217 g in mercury at 20° C. It was lapped with diamond dust to such an accurate form and good surface finish that the standard deviation of the volume of mercury displaced, as calculated from optical interference measurements of the dimensions of the cube, is 0.15 p.p.m. (part per million). The determined mass of the cube has a standard deviation of 0.1 p.p.m. and the measured weight of the cube in any one sample of mercury at 20° G has a standard deviation of 0.28 p.p.m. The uncertainty in the density of any one sample of mercury is however greater, for two reasons, than the value of 0.3 p.p.m. that these figures indicate. First, all measurements of the temperature of the mercury are subject to a constant error which may reach 0.001 ° C, equivalent to 0.2 p.p.m. of the density of mercury. Secondly, and more important, the effective volume of the cube may be greater than the measured volume through layers of grease adhering to it despite very careful cleaning and the corresponding error probably varied from one group of weighings to another; it is difficult to estimate but is thought to be between 0.2 and 1 p.p.m. The mean density at 20° C and 1 atm pressure of four samples of mercury from different sources is 13.545892 g/cm3, the range of the four values being 1.1 p.p.m. The corresponding value at 0° C, calculated from the thermal expansion formula of Beattie, Blaisdell, Kaye, Gerry & Johnson (1941) is 13.595086 g/cm3. The chemical and isotopic compositions of the samples cannot be specified with an accuracy corresponding to that of the measurements, but evidence is given indicating that our results should represent the density of pure mercury of average isotopic constitution to between 1 and 2 p.p.m. Complementary measurements are now being prepared in which the mass of mercury that fills a box of fused silica is to be found.

Interferometric Examination

WE have applied multiple-beam interference methods to the study of abrasion test marks cut in diamond surfafces prepared for us by a new method due to P. Grodzinski (see above note). In this abrasion test the directional mechanical properties of the diamond are revealed by the sizes of the cuts produced in the various directions by (as near as possible) the same number of revolutions, under constant load, of a sharp grinding wheel charged with diamond dust. The accompanying illustrations are interferometric studies made on the cube top face of a truncated pyramid of a ‘glassy’ diamond, the same face, in fact, as that described in the preceding note by Grodzinski and Stern.

Notes on the cleaving and sawing of diamond

It seems to be a peculiarity in the history of the diamond that from time to time operations which have been known from time immemorial are re-invented and claimed to be new. For instance, cleaving, which is said to have been known to the Indians, was discovered again by W. H. Wollaston. It is obvious, too, that cleaving was already known to A. B. de Boodt in 1604. The same applies to the sawing of gems by a thin rotating disk, which seems to be as old as the engraver's treadle lathe (earliest reference about 1520) ; but this art does not seem to have been applied to diamonds, as the first reference to diamond sawing with a thin rotating blade is that in 1874. All previous references seem to be to the sawing of diamonds with a thin wire moistened with a paste of diamond dust and oil, and otherwise designated as the Chinese method. Other gemstones, were always sawn with thin disks on lapidaries' benches with vertical spindle. Similar remarks may be applied to bruting and drilling, but only polishing seems to have always been recognized as the main operation.

Lattice Constant of Diamond and the C–C Single Bond

RECENTLY, Lonsdale1 has published a brief account of her measurements on single crystals of diamond using the divergent beam method2. At the same time, measurements were made by me on a specimen of diamond dust employing the X-ray powder method developed to a high degree of precision by Bradley and Jay3 and others. The two sets of measurements are of interest to the physicist because they provide a comparison of the accuracy obtainable by the powder method with that obtainable by Lonsdale's method; they are of interest to the chemist because they lead to the most accurate value yet of the C–C single bond in diamond.

Diamond dust is recovered for “hardest” war industry jobs

Diamond dust is recovered for “hardest” war industry jobs

Dr. Watt's Dictionary of the Economic Products of India

IN your recent review of the above work, attention is drawn to the startling statement that “Diamond dust is known to be a powerful mechanical poison.” This statement, occurring as it does in an official work, issued by the Government of India, aroused my amazement when I first had occasion to consult the Dictionary. It occurred to me then, and I still think, that the author would have done better to have quoted the words of Colonel Wilks on the subject (“South of India,” vol. ii. p. 197), namely, “Whatever doubts may be entertained of the fact, there is none regarding the belief [by the Mahommedans of Southern India in the power of diamonds as a poison], and the supposed powder of diamonds is kept as a last resource like the sword of the Roman, but I never met with any person, who from his own knowledge could describe its visible effects, &c.”

Poisoning by diamond dust

Poisoning by diamond dust Get access W. T. M. W. T. M. 1Shinfield Grove Search for other works by this author on: Oxford Academic Google Scholar Notes and Queries, Volume s5-III, Issue 75, 5 June 1875, Page 453, https://doi.org/10.1093/nq/s5-III.75.453f Published: 05 June 1875

Poisoning by diamond dust

Poisoning by diamond dust

Poisoning by diamond dust

Poisoning by diamond dust

Poisoning by Diamond Dust

Poisoning by Diamond Dust Get access J. P. Morris J. P. Morris Search for other works by this author on: Oxford Academic Google Scholar Notes and Queries, Volume s5-III, Issue 68, 17 April 1875, Page 308, https://doi.org/10.1093/nq/s5-III.68.308a Published: 17 April 1875

Poisoning by Diamond Dust

Poisoning by Diamond Dust

Poisoning by diamond-dust

Poisoning by diamond-dust