Macroscopic effects

Albers, P.H., D.E. Green, and C.J. Sanderson. 1996. Diagnostic criteria for selenium toxicosis in aquatic birds dietary exposure, tissue concentrations, and macroscopic effects. Jour. Wildl. Dis. 32 468-485 Correction. Jour. Wildl. Dis. 32 725-726. 

Even though the presence of a dielectric material in an Electric (E) field inv olves phenomenon at the atomic scale, it is possible to represent the overall macroscopic effect from equations (15.1) and (15.3). 

It must be kept in mind, however, that CE data resemble a macroscopic effect of complexation and, like ultrafiltration or size exclusion chromatography CE, do not give information on specific binding sites. Despite the existence of a well-established theoretical basis, it is not possible to get reliable complexation constants, for practical reasons, if too many complexation processes are involved at the same time. Often the combination with spectroscopic investigations, especially with NMR and fluorimetry, may provide more details. 

Surface tension and contact angle phenomena play a major role in many practical things in life. Whether a liquid will spread on a surface or will break up into small droplets depends on the above properties of interfaces and determines well-known operations such as detergency and coating processes and others that are, perhaps, not so well known, for example, preparation of thin films for resist lithography in microelectronic applications. The challenge for the colloid scientist is to relate the macroscopic effects to the interfacial properties of the materials involved and to learn how to manipulate the latter to achieve the desired effects. Vignette VI provides an example. 

At the beginning of the analysis, the ensemble of frequencies is incoherent and has no measurable macroscopic effect on the cell. Ions with the same m/z ratio must be made coherent to conduct a frequency analysis. This is achieved by irradiating the cell with a short radiofrequency pulse (ca. 1 ms lifetime) that includes all the frequencies to be determined. During the irradiation pulse, ions will increase their... 

We return to the bistable situation with clearly separated time scales and suppose that the system starts out at a site near the boundary of Da, i.e., close to the macroscopically unstable point (f)b. Then in the initial stage fluctuations across are not improbable. There is therefore a non-negligible probability that the system does not follow the macroscopic path towards (j>a but ends up in 4>c instead. Thus near a point of macroscopic instability fluctuations give rise to a macroscopic effect. It is therefore no longer possible to separate a macroscopic part from a fluctuation term as in (X.2.9) and treat the fluctuations as a small perturbation. The conclusion is that there exists no mesostate related to the stationary macrostate. Any probability distribution originally peaked near (j)b evolves in time and does not remain localized. The evolution occurs in three successive stages. 

In contrast, the combustion temperatures recorded for the tantalum-nitrogen and niobium-nitrogen systems were much lower than the melting points of the respective metals. Photographs of the cross-sections of undiluted samples do not indicate any macroscopic effect of melting, and neither do SEM photographs of the products. 

In my opinion, an active centre of alkene polymerization in the liquid phase is not a single chemical entity to be visualized by a single (and simple) chemical formula. Probably a set of compounds, of complexes with variable composition, a dynamic system where the effects of individual components are mutually complementary or overlapping is really in play. The same macroscopic effect (centres of equal activity and iso-specific regulating ability) can be obtained with various starting organometals and donors. In such a system, subsystems may exist each of which is externally manifested as an individual active centre (rapid or slow, isotactic, with a tendency to transfer or termination, or living, etc.) [225],... 

In tlie gaseous state, molecules possess a liigli degree of translational kinetic energy, which means tliat tliey arc able to move quite freely tlirougliout the body of the gas. For e.xamplc, when gas is in an enclosed container, tlie molecules are constantly bombarding tlie container walls. The macroscopic effect of this bombardment by a tremendous number of molecules - enough to make the effect measurable - is called pressure. Hie natural miits of pressure are those of force per unit area. 

Molecular Basis of Macroscopic Effects - Spectroscopic Investigations... 

Intercalation is a complex process. Reactions involve adsorption of guest species on host crystals, exchange or insertion at the host surface, the formation of intermediate stages in layered compounds, and transport within the host lattice. Macroscopic effects such as variations in crystal size. 

The variation of TPAOH amount during the synthesis of silica-aluminas has two macroscopic effects the change of the pH and of the relative amount of TPAOH to silico-aluminate oligomers. The textural properties of the final silica-aluminas may result from the different sequence of hydrolysis and condensation reactions (and the reverse reactions esterification and alcoholic or hydrolytic depolymerization) of the Si and A1 alkoxides. Indeed an increase in TPAOH content and therefore of the pH corresponds to an increase of OH" availability that can favor the hydrolysis and depolymerization reactions, giving rise to different gelation rate and to different network formation. 

The theory of dislocations - what they are, what they do, and how they produce macroscopic effects that can be observed and measured - was highly developed (Read 1953) before individual dislocations were routinely observed directly by transmission electron microscopy. Dislocations and... 

During ultrasonic irradiation of aqueous solutions, OH radicals are produced from dissociation of water vapor upon collapse of cavitation bubbles. A fraction of these radicals that are initially formed in the gas phase diffuse into solution. Cavitation is a dynamic phenomenon, and the number and location of bursting bubbles at any time cannot be predicted a priori. Nevertheless, the time scale for bubble collapse and rebound is orders of magnitude smaller than the time scale for the macroscopic effects of sonication on chemicals (2) (i.e., nanoseconds to microseconds versus minutes to hours). Therefore, a simplified approach for modeling the liquid-phase chemistry resulting from sonication of a well-mixed solution is to view the OH input into the aqueous phase as continuous and uniform. The implicit assumption in this approach is that the kinetics of the aqueous-phase chemistry are not controlled by diffusion limitations of the substrates reacting with OH. 

Intuitively, one might have expected radiation to increase rather than to decrease surface area because damage implies breaking up of crystals into smaller units. There is some evidence for macroscopic effects of this sort as a result of bombardment. The formation of tridymite crystals in silica xerogel (by neutron bombardment) was aptly termed 128) a brutal destruction of the original texture the measured surface area, however, decreased in this case. A phase transformation has also been induced in beryllia by electron bombardment in an electron... 

Moreover, chemists use items characterized in chemical terms reliably to produce various macroscopic effects synthesis is not only a huge area of academic chemistry, but the job of any of a number of whole commercial and other worldly industries. Chemists take various molecules and cut and paste them together into useful substances never found in nature, most notably pharmaceuticals and plastics. It would never occur to any such worker to doubt that her/his raw materials were real or that they had most of the features ascribed to them by classical chemical theory. Historicist claims, and postmodernist vaporings, seem irrelevant and silly here. 

In 1922 Henderson [1] postulated that a-particles might be used to detonate explosives, and there has been a continuing interest in whether self-sustaining reactions can be initiated by nuclear or optical radiation of selected energies. The molecular or electronic aspects of the subject are described in Volume 1 this chapter, therefore, is devoted primarily to macroscopic effects. 

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