Quasi-cycles

In triphenyltellurium diphenyldithiophosphinate, [Ph3Te]+ [S2PPh2] and triphenyltellurium tetraphenyldithioimi-dodiphosphinate, [Ph3Te]+ [(SPPh2)2N], probably ionic interactions and Te- S secondary bonding are simultaneously acting to close a four- and a six-membered quasi-cycle, respectively (Scheme 14). ... 

FIGURE 5.13 Gaussian band pass filtered WIBIX series describing fluctuations in the energetic level of quasi-cycles with periods between 8.2 and 15 years modified from Hagen (2006) the used filter is discussed in more detail by Schonwiese (2000). 

Fig. 22. The capacity of the one volt plateau measured during the second cycle of several series of samples versus the H/C atomic ratio in the samples. The solid line suggests that each lithium atom binds quasi-reversibly to one hydrogen atom.

Throughout this chapter many of the arguments are based on an assumption of steady state. Before the agricultural and industrial revolutions, the carbon cycle presumably was in a quasi-balanced state. Natural variations still occur in this unperturbed environment the Little Ice Age, 300-400 years ago, may have influenced the carbon cycle. The production rate of varies on time scales of decades and centuries (Stuiver and Quay, 1980,1981), implying that the pre-industrial radiocarbon distribution may not have been in steady state. 

We started by analyzing the dominant modes of oscillation showed by oxygen content, streamflow, and ENSO using the Maximum Entropy Method (MEM) (Table 1). It is remarkable that both the streamflow to the reservoir and the AF showed common oscillations with ENSO at fi-equencies between 0.016 and 0.035 cycles month These frequencies are very close to the two main periods of ENSO (the quasi-biennial and quasi-quadrennial periods) [56]. Although we do not have a mechanistic explanation for this teleconnection (in fact the extratropical influence of ENSO is a hot topic in climate research, Merkel and Latif [57]), it is certainly difficult to propose an alternative explanation for the oscillations in AF and stream-flow observed at these frequencies. 

It is demonstrated in Figure 22.11 that the quasi-static stress-strain cycles at different prestrains of silica-filled rubbers can be well described in the scope of the above-mentioned dynamic flocculation model of stress softening and filler-induced hysteresis up to large strain. Thereby, the size distribution < ( ) has been chosen as an isotropic logarithmic normal distribution (< ( i) = 4> ) = A( 3)) ... 

X02 = 0.1. They examined the effect of temperature (673 to 798 K), space-time (0.01 ts 4 s), and cycling strategy on rate enhancement. Resonance was observed for rs = 0.1 s with P > 1 for temperatures up to 770 K at a cycle period of about 1000 s. Above 770 K, rqss > r so that resonance disappeared. The quasi-steady-state rate, rqss, decreased rapidly with de-... 

Multiple resonance was observed at T = 723 K and rs = 0.01 s. The enhancement, exceeds 1 at a cycle period between 0.2 and 0.3 s and also at greater than 1000 s, although quasi steady state is also attained at about that period. Resonance also occurs at two different cycle periods at ts = 0.02 s, T is much smaller. As the space-time increases above 0.25 s, the rate enhancement becomes very small and the multiple resonance phenomenon seems to disappear. 

Gomez-Sainero et al. (11) reported X-ray photoelectron spectroscopy results on their Pd/C catalysts prepared by an incipient wetness method. XPS showed that Pd° (metallic) and Pdn+ (electron-deficient) species are present on the catalyst surface and the properties depend on the reduction temperature and nature of the palladium precursor. With this understanding of the dual sites nature of Pd, it is believed that organic species S and A are chemisorbed on to Pdn+ (SI) and H2 is chemisorbed dissociatively on to Pd°(S2) in a noncompetitive manner. In the catalytic cycle, quasi-equilibrium ( ) was assumed for adsorption of reactants, SM and hydrogen in liquid phase and the product A (12). Applying Horiuti s concept of rate determining step (13,14), the surface reaction between the adsorbed SM on site SI and adsorbed hydrogen on S2 is the key step in the rate equation. 

Far from a wellbore, the velocity of reservoir fluids is about one linear foot per day. Near a wellbore, the velocity can increase one-hundred fold. A static or quasi-static test such as the sessile drop (contact angle) test may not represent the dynamic behavior of the fluids in the field. The dynamic Wilhelmy device gives results which are comparable in interface velocity to the field displacement rate. The interface in the Wilhelmy test described here moved at a steady rate of 0.127 mm/sec or 36 ft/day. The wetting cycle for a hybrid-wetting crude oil system was not affected by moving at a rate less than 1 ft/day. 

In the individual compartments quasi-steady state is achieved depending on emissions, degradation rates and spatial distribution of DDT. According to the seasonality of the parameters affecting degradation rates, e.g. temperature and oxidant abundance, the compartmental burdens in steady state follow a seasonal cycle. As the sources and consequently most of the DDT mass is located in the northern hemisphere, the cycle is defined by the climate of that hemisphere. Times needed to to achieve quasi staty state in the compartments are equal in the AGG and SAT experiment, as well as amplitude and phase of the burden time series. Vegetation reaches quasi-steady state within 2-4 years, and atmosphere already within 2 years. These... 

By today s standards of surface preparation, Will s procedures for surface preparation were crude, the surface structures were not characterized by use of surface analytical instrumentation (Which was neither widely available nor well developed at that time), and he employed extensive potentiodynamic cycling through the "oxide" formation potential region prior to reporting the quasi-steady state voltammetry curve, i.e., the potentiodynamic I-V curve. The studies employing surface analytical methods made a decade or more later were... 

Experimental results are presented that show that high doses of electron radiation combined with thermal cycling can significantly change the mechanical and physical properties of graphite fiber-reinforced polymer-matrix composites. Polymeric materials examined have included 121 °C and 177°C cure epoxies, polyimide, amorphous thermoplastic, and semicrystalline thermoplastics. Composite panels fabricated and tested included four-ply unidirectional, four-ply [0,90, 90,0] and eight-ply quasi-isotropic [0/ 45/90]s. Test specimens with fiber orientations of [10] and [45] were cut from the unidirectional panels to determine shear properties. Mechanical and physical property tests were conducted at cold (-157°C), room (24°C) and elevated (121°C) temperatures. 

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