Unique particles proportion

As can be seen from Table 19.3, the proportion of indicative particles exceeds the proportion of unique particles, even for promptly collected FDR. The higher proportion of indicative particles detected in casework is almost certainly due to particles from nonfirearm sources, particularly single primary element ones, meeting the criteria of the classification scheme. 

The frictional properties of TPs, specifically the reinforced and filled types, vary in a way that is unique from metals. In contrast to metals, even the highly reinforced plastics have low modulus values and thus do not behave according to the classic laws of friction. Metal-to-thermoplastic friction is characterized by adhesion and deformation resulting in frictional forces that are not proportional to load, because friction decreases as load increases, but are proportional to speed. The wear rate is generally defined as the volumetric loss of material over a given unit of time. Several mechanisms operate simultaneously to remove material from the wear interface. However, the primary mechanism is adhesive wear, which is characterized by having fine particles of plastic removed from the surface. 

Solids appear in one of two forms, either as crystals or powders. The difference is one of size, since many of the powders we use are in reality very fine crystals. This, of course, depends upon the manner in which the solid is prepared. Nevertheless, most solids that we encounter in the real world are in the form of powders. That is, they are in the form of discrete small particles of varying size. Each particle has its own unique diameter and size. Additionally, their physical proportions can vary in shape from spheres to needles. For a given powder, aU grains will be the same shape, but the particle shape and size can be eiltered by the method used to create them in the first place. Methods of particle formation include ... 

T nterest in the separation of isotopes started as a scientific curiosity. The question arose as to whether it was indeed at all feasible or possible to separate isotopes. After this question was answered in the affirmative (24), it became of interest to separate isotopes on a laboratory scale for use in scientific research. A few examples show the range of utility of separated isotopes. Deuterium has attained widespread use as a biochemical and chemical tracer. It is now abundantly available and is used as freely as any cheap chemical reagent. He has opened up an entirely new field of research in low temperature physics and has important applications in the production of temperatures below 1°K. with a thermal neutron cross section of 4,000 barns, has found wide use in nuclear particle detectors—neutron proportional counters. still finds use as a tracer, but in recent years its most frequent use has been in electron spin and nuclear magnetic resonance spectroscopy. occupies a unique position as the only usable tracer for nitrogen. finds application as a... 

In a sense, the chemists also avoided the physical issue of whether elements were necessary in a mechanistic universe by focusing on the functional aspects of the material world. Simply by establishing that elements had unique characteristics, they could differentiate matter. Elements could be identified, classified, isolated, and used in experiments. If Descartes, Boyle, and Newton pictured matter as some form of prime particles differentiated only by proportion, mass, or size, it did not really matter to chemists. So long as the resulting products had unique and unchanging properties, the designation element was both practical and scientifically justified. While what made an element unique would continue to be a profound scientific question, by the beginning of the nineteenth century chemists were convinced that elements were real and that they served as a sound basis for scientific research. 

Each radioisotope formed in an element subject to a nuclear particle bombardment is uniquely characterized by its half-life (rate of decay) and the types and energies of the radiations it emits as it decays. Therefore, a positive identification of the radioelement is possible. The amount of element in the bombarded or activated sample can be determined directly from a measurement of the radionuclide s radioactivity because the induced radioactivity is directly proportional to the number of atoms of the stable isotope in the sample and to the intensity (flux) of the nuclear particles interacting with the stable nuclei. 

In a formula representing two volumes of vapour, the sum of the numbers of atoms (proportional numbers) of hydrogen, nitrogen, phosphorus, arsenic, and halogens is an even number. He then introduces the unitary view, in which a molecule is regarded as an edifice, a unique system formed by the assembly in a determinate but unknown order, of infinitely small particles called atoms , either of the same kind in a simple body or of different kinds in a compound body. No distinction is to be made between the two kinds of molecules. He says the equivalent depends on what other body, in what functions, with what proportions, this equivalent is to correspond . 

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