Mass, concept

In the chain reaction shown in Figure 14.5, if there is so little uranium that the released neutrons escape before they have a chance to cause a fission reaction, the reaction stops. The critical mass is the minimum mass of fissionable material needed in order for the reaction to continue. The critical mass concept is the key to the design of a fission-type nuclear weapon. In such a weapon, two smaller-than-critical masses are present but are separated. When these subcritical masses are suddenly combined, the rapidly escalating fission reactions produce an explosion of incredible intensity. 

Using the center of mass concept of fuzzy sets, the symmetry deficiency measure of finite continua, described in Section VIII, can be generalized for fuzzy sets. The chirality and more general symmetry deficiencies of fuzzy sets can be treated within a unified framework using the fuzzy metric FSNDSM diJ A,B). 

The numerical expression of the phenomenon was always found as proportional with the mass and in any case the increasing mass was not been followed by a recurrence of the properties as a periodical law of the elements. This was a novelty in the natural phenomena study even if it was not appropriate to the purpose which define the truth about the mass concept, it was not indicated that the explanation of such a concept to be searched in the atomic masses. Moreover, as long as the masses are... 

Nonintermeshing counterrotating machines have the oldest technology (19). The Parrel continuous mixer (PCM) remains today as a good compromise of the Banbury batch mixer but with continuous mixing capability with the small mass concept. The incorporation of various fillers into polypropylene (talc, calcium carbonate, etc.) at 30-80 wt% levels is still accomplished via the PCM. 

Because the equivalent-mass concept assumes all pressure transients to be instantaneous, the integrand of dS is independent of 6 thus... 

The Tag-Mass Concept Selective Multiplexed Imaging of Biomolecules from Tissue Sections... 

The ice force records are digitized based on the Nyquist frequency criterion. Fluid-structure interaction is considered in an approximate manner using the frequency-independent added mass concept, i.e. added mass equal to the mass of water displaced. The equivalent evolutionary white noise, is based on the maximum peak of the averaged power spectrum and the evolutionary white noise is considered as a two-segment piece-wise linear function, as shown in Fig 3. The random excitation, Y(t), can be decomposed as follows ... 

Now some theoretical results for simple compounds, obtained within the scope of the effective-mass conception, will be discussed. The selected examples have been proved to be in agreement with experiment in many measurements. 

The effective mass concept is only defined near a band maximum or minimum where the energy can be approximated as a quadratic function of wave vector, k. Note that near a minimum in energy bands the E(k) function is concave up and 1/m >0 while near a maximum, 1/m <0. The negative effective mass near a maximum indicates that charge is being carried by holes rather than electrons. 

Benninghoven A, Rudenauer F G and Werner FI W 1987 Secondary ion Mass Spectrometry Basic Concepts, instrumentai Aspects, Appiications, and Trends (New York Wiley)... 

Guilhaus M 1995 Principles and instrumentation in time-of-flight mass spectrometry physical and instrumental concepts J. Mass Spectrom. 30 1519-32... 

The pump-probe concept can be extended, of course, to other methods for detection. Zewail and co-workers [16,18, 19 and 2Q, 93] have used the probe pulse to drive population from a reactive state to a state that emits fluorescence [94, 95, 96, 97 and 98] or photodissociates, the latter situation allowing the use of mass spectrometry as a sensitive and selective detection method [99, 100]. 

We will now explain the meaning of the word identical used above. Physically, it is meant for particles that possess the same intrinsic attributes, namely, static mass, charge, and spin. If such particles possess the same intrinsic attributes (as many as we know so far), then we refer to them as physically identical. There is also another kind of identity, which is commonly refeiTed to as chemical identity [56]. As discussed in the next paragraph, this is an important concept that must be steessed when discussing the permutational properties of nuclei in molecules. 

Specinfo, from Chemical Concepts, is a factual database information system for spectroscopic data with more than 660000 digital spectra of 150000 associated structures [24], The database covers nuclear magnetic resonance spectra ( H-, C-, N-, O-, F-, P-NMR), infrared spectra (IR), and mass spectra (MS). In addition, experimental conditions (instrument, solvent, temperature), coupling constants, relaxation time, and bibliographic data are included. The data is cross-linked to CAS Registry, Beilstein, and NUMERIGUIDE. 

The nebulization concept has been known for many years and is commonly used in hair and paint spays and similar devices. Greater control is needed to introduce a sample to an ICP instrument. For example, if the highest sensitivities of detection are to be maintained, most of the sample solution should enter the flame and not be lost beforehand. The range of droplet sizes should be as small as possible, preferably on the order of a few micrometers in diameter. Large droplets contain a lot of solvent that, if evaporated inside the plasma itself, leads to instability in the flame, with concomitant variations in instrument sensitivity. Sometimes the flame can even be snuffed out by the amount of solvent present because of interference with the basic mechanism of flame propagation. For these reasons, nebulizers for use in ICP mass spectrometry usually combine a means of desolvating the initial spray of droplets so that they shrink to a smaller, more uniform size or sometimes even into small particles of solid matter (particulates). 

Benninghoven, A., Rudenauer, F.G., and Werner, H.W., Secondary Ion Mass Spectrometry Basic Concepts, Instrumental Aspects, Applications and Trends, Wiley, New York, 1987. 

Basically, Newtonian mechanics worked well for problems involving terrestrial and even celestial bodies, providing rational and quantifiable relationships between mass, velocity, acceleration, and force. However, in the realm of optics and electricity, numerous observations seemed to defy Newtonian laws. Phenomena such as diffraction and interference could only be explained if light had both particle and wave properties. Indeed, particles such as electrons and x-rays appeared to have both discrete energy states and momentum, properties similar to those of light. None of the classical, or Newtonian, laws could account for such behavior, and such inadequacies led scientists to search for new concepts in the consideration of the nature of reahty. 

Another concept sometimes used as a basis for comparison and correlation of mass transfer data in columns is the Clulton-Colbum analogy (35). This semi-empirical relationship was developed for correlating mass- and heat-transfer data in pipes and is based on the turbulent boundary layer model... 

Discussion of the concepts and procedures involved in designing packed gas absorption systems shall first be confined to simple gas absorption processes without compHcations isothermal absorption of a solute from a mixture containing an inert gas into a nonvolatile solvent without chemical reaction. Gas and Hquid are assumed to move through the packing in a plug-flow fashion. Deviations such as nonisotherma1 operation, multicomponent mass transfer effects, and departure from plug flow are treated in later sections. 

Equation 39 can often be simplified by adopting the concept of a mass transfer unit. As explained in the film theory discussion eadier, the purpose of selecting equation 27 as a rate equation is that is independent of concentration. This is also tme for the Gj /k aP term in equation 39. In many practical instances, this expression is fairly independent of both pressure and Gj as increases through the tower, increases also, nearly compensating for the variations in Gj. Thus this term is often effectively constant and can be removed from the integral ... 

Adsorption Dynamics. An outline of approaches that have been taken to model mass-transfer rates in adsorbents has been given (see Adsorption). Detailed reviews of the extensive Hterature on the interrelated topics of modeling of mass-transfer rate processes in fixed-bed adsorbers, bed concentration profiles, and breakthrough curves include references 16 and 26. The related simple design concepts of WES, WUB, and LUB for constant-pattern adsorption are discussed later. 

For smaller particles, the theory indicates that efficiency decreases according to the dotted line of Figure 7. Experimental data (134) (sofld line of Eig. 7) for a cyclone of Eig. 9 dimensions show that equation 15 tends to overstate collection efficiency for moderately coarse particles and understate efficiency for the finer fraction. The concept of particle cut-size, defined as the size of particle collected with 50% mass efficiency, determined by equation 16 has been proposed (134). 

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