Open system processes

Open system The behaviour of the REE in a periodically replenished, periodically tapped, processes continuously fractionated (RTF) magma chamber (Section 4.2.2) is described by O Hara and Matthews (1981). Using chondrite-normalized values of Ce/Yb to represent the slope of the REE diagram, and Sm values as a measure of REE 

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The process in this invention uses and applies an open system process for receiving excess energy from an external source (the permanent-magnet flux and A potentials), and since the permanent-magnet flux and A potentials are continuously replenished from the vacuum via the broken 3-symmetry of the magnet dipolarity via its Whittaker decomposition [1], the process is allowed to... 

Effect of crustal melting and open-system processes (contamination, recharge, and crustal melting) on differentiation ages... 

In particularly favorable cases, inferences about magma residence times can be derived from other isotopic systematics, most notably Rb- Sr (Davies et al., 1994 Halliday et al., 1989). Extremely evolved magmas can have sufficiently high Rb/Sr for Sr isotope signatures to evolve detectably on timescales commensurate with magmatic processes, enabhng the time since differentiation to high Rb/Sr to be delimited. Correlations between diverse Rb/Sr and Sr/ Sr in some suites of silicic lavas may be dominantly those of in situ decay rather than open-system processes, in which case they delimit the differentiation events... 

In order to achieve these aims, and to limit the length of the chapter, we have not provided a detailed review of theories regarding the origin of primitive arc basalts, the mixing of magmatic components derived from the upper mantle, aqueous fluids, and sediment melts, or open-system processes in the cmst including mixing and assimilation. For a more complete view of these theories, we refer the reader to the many excellent review papers and individual smdies that are, all too briefly, cited below. 

Equation (54) applies in a beaker system, where all fluid arrives unreacted and simultaneously equilibrates with the rock within a defined volume. In the isotope literature (e.g. Taylor 1977) this is referred to as closed system isotope exchange. Alternatively, infiltration has been considered an open-system process such that each infinitely small aliquot of fluid equilibrafes and fhen leaves the system. In this case the appropriate relation is... 

In addition to its generality, the form (7.1.48) is important because it leads to a computational strategy for analyzing phase-equilibrium situations. In that strategy, a phase-equilibrium problem is treated as a multivariable optimization in which the Ihs of (7.1.48) is the quantity to be minimized. An alternative strategy, in which the computational problem is to solve a set of coupled nonlinear algebraic equations, arises from the constraints on open-system processes developed in 7.2. 

Open-system processes may include chemical reactions, diffusional mass transfer, and energy transfer across system boundaries. All such processes must satisfy the open-system form of the combined laws. When these processes are all complete and equilibrium is established, then it is the equality in (7.5.10) that applies. However, this statement is only a necessary condition it is not sufficient. The necessary and sufficient conditions for equilibrium are that each term in (7.5.10)—including each term in each sum—must be zero. In other words, the system must simultaneously satisfy the criteria already discussed for thermal equilibrium (7.3.3), mechanical equilibrium (7.3.5), diffusional equilibrium (7.3.11) or (7.3.12), and reaction equilibrium (7.6.3). 

M. J. Streck, Mineral Textures and Zoning as Evidence for Open System Processes, Minerals, Inclusions and Volcanic Processes, Reviews in Mineralogy Geochemistry, Mineralogical Society of America, Vol. 69, pp. 595-622, 2008... 

Liquefaction is essentially an open-system process therefore, for the ideal liquefaction system, two processes from the Carnot cycle are utilized, namely, a reversible isothermal compression followed by a reversible isentropic expansion. This reversible liquefaction cycle is shown in Fig. 4.3. The pressure that must be attained at the end of the isothermal compression for even an ideal nitrogen liquefaction system is extremely high—on the order of 70,000 MPa. It is impossible to attain such pressures with existing compression equipment. 

Taking into account the hydration shell of the NA and the possibility of the water content changing we are forced to consider the water -I- nucleic acid as an open system. In the present study a phenomenological model taking into account the interdependence of hydration and the NA conformation transition processes is offered. In accordance with the algorithm described above we consider two types of the basic processes in the system and thus two time intervals the water adsorption and the conformational transitions of the NA, times of the conformational transitions being much more greater... 

The ring system 13.18 (R = Cl) is a source of hybrid PN/SN polymers containing three-coordinate sulfur via a ring-opening polymerization process. This polymerization occurs upon mild thermolysis at 90°C (Section 14.4)." ... 

In general, for all real processes, there is a net production of entropy and Equation 2-113 applies. Since many practical engineering processes involve open systems, it is useful to develop a generalized expression of the second law applied to such systems. 

Capaldi G, Cortini M, Pece R (1982) Th isotopes at Vesuvius evidence for open-system behavior of magma-forming processes. J Volcanol Geotherm Res 14 247-260 Capaldi G, Cortini M, Pece R (1983) U and Th decay-series disequilibria in historical lavas from the Eolian islands, Tyrrhenian Sea. Isot Geosci 1 39-55... 

Atmospheric evaporators are more commonly used. They are open systems that use process heat and warm air to evaporate water. These evaporators are relatively inexpensive, require low maintenance and are self-operating. Under the right conditions, they can evaporate water from virtually any plating bath or rinse. A packed-bed evaporator is an example of an atmospheric evaporator. 

The key is to recognize that the system may exhibit underdamped behavior even though the open-loop process is overdamped. The closed-loop characteristic polynomial can have either real or complex roots, depending on our choice of Kc. (This is much easier to see when we work with... 

Semibatch or semiflow processes are among the most difficult to analyze from the viewpoint of reactor design because one must deal with an open system under nonsteady-state conditions. Hence the differential equations governing energy and mass conservation are more complex than they would be for the same reaction carried out batchwise or in a continuous flow reactor operating at steady state. 

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