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Materials in study

There are also significant species differences in respiratory tract deposition and clearance of inhaled particles (Thomas, 1972). Data from a number of studies are summarized in Table 14 to assist in evaluating the several factors that influence the retention of inhaled materials. In studies with rats, Syrian hamsters, Chinese hamsters, and mice, the l44Ce was generally lost at a more rapid rate from the pulmonary region than was noted for the dog. A major factor in this difference may be differences in initial deposition sites and perhaps... [Pg.35]

Janaway, R. C. (1996). The decay of buried remains and their associated materials, in Studies in Crime An Introduction to Forensic Archaeology (J. Hunter, C. Roberts, and A. Martin, Eds.). London Routledge, 58-85. [Pg.47]

Polyimide was used as a model material in studies of polymer metal interfaces where metal layers were formed by metallization, plasma deposition, chemical vapor deposition, electrochemical deposition, etc In most of the cases studied, the interpenetration of metal was so good that the metal layer could not be removed by any other means but abrasion. An investigation of interface, determined that the metal particles were found in the surface layers in diminishing quantities perpendicular to the surface and not, as expected, in the form of a sharp borderline between the metal and polymer. Some difficulties exist when metallized polyimides are used for chip production. These diffuse layers of metals complicate design and performance due to the gradients of conductivity which they produce. [Pg.656]

FiCURE 31.13 Experimental and FEA results for the radiation sterilized material in study 1 [12],... [Pg.481]

Two types of materials are studied in the CIAPES programme ferritic steel and stainless steel. A database for vessels monitored by acoustic emission has been builded to collect the results of all the tests carried out in laboratory and in situ. [Pg.55]

There has been a general updating of the material in all the chapters the treatment of films at the liquid-air and liquid-solid interfaces has been expanded, particularly in the area of contemporary techniques and that of macromolecular films. The scanning microscopies (tunneling and atomic force) now contribute more prominently. The topic of heterogeneous catalysis has been expanded to include the well-studied case of oxidation of carbon monoxide on metals, and there is now more emphasis on the flexible surface, that is, the restructuring of surfaces when adsorption occurs. New calculational methods are discussed. [Pg.802]

Because the neutron has a magnetic moment, it has a similar interaction with the clouds of impaired d or f electrons in magnetic ions and this interaction is important in studies of magnetic materials. The magnetic analogue of the atomic scattering factor is also tabulated in the International Tables [3]. Neutrons also have direct interactions with atomic nuclei, whose mass is concentrated in a volume whose radius is of the order of... [Pg.1363]

As discussed in more detail elsewhere in this encyclopaedia, many optical spectroscopic methods have been developed over the last century for the characterization of bulk materials. In general, optical spectroscopies make use of the interaction of electromagnetic radiation with matter to extract molecular parameters from the substances being studied. The methods employed usually rely on the examination of the radiation absorbed. [Pg.1778]

The application of RBS is mostly limited to materials applications, where concentrations of elements are fairly high. RBS is specifically well suited to the study of thin film stmctures. The NMP is usefiil in studying lateral inliomogeneities in these layers [30] as, for example, in cases where the solid state reaction of elements in the surface layers occur at specific locations on the surfaces. Other aspects, such as lateral diffusion, can also be studied in tluee-dimensions. [Pg.1844]

Because of the risk of lead poisoning, the exposure of children to lead-based paint is a significant public health concern. The first step in the quantitative analysis of lead in dried paint chips is to dissolve the sample. Corl evaluated several dissolution techniques. " In this study, samples of paint were collected and pulverized with a Pyrex mortar and pestle. Replicate portions of the powdered paint were then taken for analysis. Results for an unknown paint sample and for a standard reference material, in which dissolution was accomplished by a 4-6-h digestion with HNO3 on a hot plate, are shown in the following table. [Pg.226]

Reactions with Ammonia and Amines. Acetaldehyde readily adds ammonia to form acetaldehyde—ammonia. Diethyl amine [109-87-7] is obtained when acetaldehyde is added to a saturated aqueous or alcohoHc solution of ammonia and the mixture is heated to 50—75°C in the presence of a nickel catalyst and hydrogen at 1.2 MPa (12 atm). Pyridine [110-86-1] and pyridine derivatives are made from paraldehyde and aqueous ammonia in the presence of a catalyst at elevated temperatures (62) acetaldehyde may also be used but the yields of pyridine are generally lower than when paraldehyde is the starting material. The vapor-phase reaction of formaldehyde, acetaldehyde, and ammonia at 360°C over oxide catalyst was studied a 49% yield of pyridine and picolines was obtained using an activated siHca—alumina catalyst (63). Brown polymers result when acetaldehyde reacts with ammonia or amines at a pH of 6—7 and temperature of 3—25°C (64). Primary amines and acetaldehyde condense to give Schiff bases CH2CH=NR. The Schiff base reverts to the starting materials in the presence of acids. [Pg.50]

Fluorescence Interference. The historical drawback to widespread use of Raman spectroscopy has been the strong fluorescence background exhibited by many materials, even those which are nominally nonfluorescent. This fluorescence often arises from an impurity in the sample, but may be intrinsic to the material being studied. Several methods have proved useflil in reducing this background. One of the simplest is sample purification. [Pg.210]


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See also in sourсe #XX -- [ Pg.156 ]




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