Substation

Fernandez A 1990 Glassy kinetic barriers between conformational substates in RNA Phys. Reine Lett. 64 2328-233... 

Nadler and Schulten, 1984] Nadler, W., and Schulten, K. Theory of Mossbauer spectra of proteins fluctuating between conformational substates. Proc. Natl. Acad. Sci. USA. 81 (1984) 5719-5723... 

Figure 8 shows a one-dimensional sketch of a small fraction of that energy landscape (bold line) including one conformational substate (minimum) as well as, to the right, one out of the typically huge number of barriers separating this local minimum from other ones. Keeping this picture in mind the conformational dynamics of a protein can be characterized as jumps between these local minima. At the MD time scale below nanoseconds only very low barriers can be overcome, so that the studied protein remains in or close to its initial conformational substate and no predictions of slower conformational transitions can be made. 

Step 1 A short conventional MD simulation (typically extending over a few lOOps) is performed to generate an ensemble of protein structures x 6 71 (each described by N atomic positions), which characterizes the initial conformational substate. The 2-dimensional sketch in Fig. 9 shows such an ensemble as a cloud of dots, each dot x representing one snapshot of the protein. 

Step 5 From that model of the current substate we construct the flooding potential of strength fl. 

H. Grubmueller and P. Tavan. Molecular dynamics of conformational substates for a simplified protein model. J. Chem. Phys. 101 (1994)... 

Mini-Subst tlons. Development of SF -iasulated lines and circuit breakers made possible development of a compact electric substation that requires one-tenth the land area of conventional designs (64,68). Other advantages of the ministation are freedom from effects of weather and pollution, and reduced risk of vandaUsm (69). Substation units ia which SF iasulates 400 and 500 kV d-c equipment have been developed (70). 

The extent of the changes in the electronic characteristics and in the very nature of the Ti02 particle surface dictates the events that take place along the photo oxidative path to mineralisation of organic substates. 

Cadmium Sulfide Photoconductor. CdS photoconductive films are prepared by both evaporation of bulk CdS and settHng of fine CdS powder from aqueous or organic suspension foUowed by sintering (60,61). The evaporated CdS is deposited to a thickness from 100 to 600 nm on ceramic substates. The evaporated films are polycrystaUine and are heated to 250°C in oxygen at low pressure to increase photosensitivity. Copper or silver may be diffused into the films to lower the resistivity and reduce contact rectification and noise. The copper acceptor energy level is within 0.1 eV of the valence band edge. Sulfide vacancies produce donor levels and cadmium vacancies produce deep acceptor levels. 

Electrical. The plant electrical system is sometimes more important than the steam system. The electrical system consists of the utihty company s entry substation, any ia-plant generating equipment, primary distribution feeders, secondary substations and transformers, final distribution cables, and various items of switch-gear, protective relays, motor starters, motors, lighting control panels, and capacitors to adjust power factor. 

The above factors apply to those items normally classified as building services. They do not include (1) services located outside the building such as substations, outside sewers, and outside water lines, all of which are considered to be outside the battery limit as well as outside the building and (2) process services. 

The teehniques of speetrophotometry determination of ion metals, eleetroehemistry deteriuination of PVP eontent in medieine, bioobjeets, waste water and speetrophotometry and ehromatography teehniques of determination of PVP moleeular masses in substation and medieine are developed with the help of polymer-dye adduets. 

Society of Power Engineers (India) Boniha Chapter. Seminar on EHV. Substations. 24 June 1994. 

If the projected pipeline is situated in an area with dc railway lines, rail/soil potential measurements should be carried out at crossing points and where the lines run parallel a short distance apart, particularly in the neighborhood of substations, in order to ascertain the influence of stray currents. Potential differences at the soil surface can give information on the magnitude of stray current effects in the vicinity of dc railway lines. It is recommended that with existing pipelines the measurements be recorded synchronously (see Section 15.5) and taken into account during design. 

Bus bars of a transformer substation must not be directly grounded. They must be connected with rails by at least two insulated cables. Metal sheathing of feeder and return current cables must only then be connected with the rails or bus bar if an increase in anodic corrosion on other buried installations is absolutely excluded. The insulation of all return cables must therefore be monitored regularly. 

The core of the network is the region of the rail network in which the branch line of two transformer substations or of any other branch line is less than 2 km distant in a direct line. All branch lines outside the core of the network are termed outlying lines. In a branched rail network, not only the stretches of line within a circle with a radius of 2 km from the most negative return current point of a transformer substation belong to the core of the network, but also connecting branch lines that are less than 2 km from each other [1]. The area of a network core can be simply determined on a track plan with the help of a circular template as in Fig. 15-1. 

The curves in Fig. 15-5 are greatly simplified and only apply to one instant of time. In practice there are always several trams with varying current draw on a stretch of track. Currents and potentials are then subjected to wide time-dependent variations. Without protective measures, the pipe/soil potentials are usually always more negative in the outer regions of a tramway system and more positive in the vicinity of the transformer substation. In a wide intermediate region, potential changes occur in both directions. The current entrance and exit areas can be deter-... 

Figure 15-8 shows synchronous recordings of the voltage between the pipeline and the rails, of the pipe/soil potential f/cu cuso4 drained current in the region of a tramway transformer substation with and without various protective measures. Figure 15-8a records values without protective measures. If the rails are negative with respect to the pipeline (f/R s > 0), the pipe/soil potential becomes more positive. Stray current exit exists. From time to time, however, < 0. 

With forced stray current drainage, the current is returned from the pipeline to the rails by means of a grid-fed rectifier. The transformer-rectifier is connected into the stray current return conductor, the negative pole is connected with the installation to be protected and the positive pole is connected to the rails or the negative side of the bus bar in the transformer substation. 

Figure 6 Thermodynamic cycle for multi-substate free energy calculation. System A has n substates system B has m. The free energy difference between A and B is related to the substate free energy differences through Eq. (41). A numerical example is shown in the graph (from Ref. 39), where A and B are two isomers of a surface loop of staphylococcal nuclease, related by cis-trans isomerization of proline 117. The cis trans free energy calculation took into account 20 substates for each isomer only the six or seven most stable are included in the plot.

Finally, an alchemical free energy simulation is needed to obtain the free energy difference between any one substate of system A and any one substate of system B, e.g., Ai- In practice, one chooses two substates that resemble each other as much as possible. In the alchemical simulation, it is necessary to restrain appropriate parts of the system to remain in the chosen substate. Thus, for the present hybrid Asp/Asn molecule, the Asp side chain should be confined to the Asp substate I and the Asn side chain confined to its substate I. Flat-bottomed dihedral restraints can achieve this very conveniently [38], in such a way that the most populated configurations (near the energy minimum) are hardly perturbed by the restraints. Note that if the substates AI and BI differ substantially, the transfomnation will be difficult to perform with a single-topology approach. 

The multisubstate approach requires initially identifying all important substates, a difficult and expensive operation. In cases of moderate complexity (e.g., a nine-residue protein loop), systematic searching and clustering have been used [39,66]. For larger systems, methods are still being developed. 

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