Counterclockwise

The order of decreasing precedence is counterclockwise The configuration at the chirality center is S... 

As viewed m the drawing a 120° counterclockwise rotation of C 4 places its hydroxyl group m the proper position At the same time this rotation moves the CH2OH group to a position such that it will become a substituent that is up on the five membered ring The hydrogen at C 4 then will be down m the furanose form... 

In order of decreasing precedence the three highest ranked groups trace a counterclockwise path... 

FIGURE 1.19 Viewing angle as a means of designating the absolute configuration of compounds with a chiral axis, (a) (R )-2-Butanol (sequence clockwise) (b) (fi)-2-butanol (sequence counterclockwise). 

A consistent direction of twist is maintained clockwise or counterclockwise rotations are equally probable. 

A constant force is applied to an ideal elastomer, assumed to be a perfect network. At an initial temperature Tj the length of the sample is Ij. The temperature is raised to Tf and the final length is If. Which is larger Ij or If (remember F is a constant and Tf > Tj) Suppose a wheel were constructed with spokes of this same elastomer. From the viewpoint of an observer, the spokes are heated near the 3 o clock position-say, by exposure to sunlight-while other spokes are shaded. Assuming the torque produced can overcome any friction at the axle, would the observer see the wheel turn clockwise or counterclockwise How would this experiment contrast, in magnitude and direction, with an experiment using metal spokes ... 

Fig. 8. Principle of the magnetooptical read-out of domain patterns by the polar Kerr effect. The polarisation plane of the incoming laser beam is rotated clock- or counterclockwise according to the orientation (up or down) of the magnetic moments.

If the observed order of priority of the remaining three functions (a > 6 > c) is in a clockwise direction, the absolute configuration is designated R (rectus or right) if counterclockwise, the configuration is S (sinister or left). The concepts of stereochemistry and chiraUty have been extensively discussed and reviewed (27—29). 

Vapor-Compression Cycles The most widely used refrigeration principle is vapor compression. Isothermal processes are realized through isobaric evaporation and condensation in the tubes. Standard vapor compression refrigeration cycle (counterclockwise Ranldne cycle) is marked in Fig. ll-72<7) by I, 2, 3, 4. 

Propeller turning counterclockwise — looking down on shoft... 

The Nyquist stability criterion can be stated as A closed-loop control system is stable if, and only if, a contour in the G s)H s) plane describes a number of counterclockwise encirclements of the (—l,jO) point, the number of encirclements being equal to the number of poles of G s)H s) with positive real parts . 

Turn valves counterclockwise to open, clockwise to close, usually. (Note that turn counterclockwise to open is inherently safer than turn to the left to open. For a multiturn valve with a wheel on a stem, turn to the left assumes the operator is looking at the side of wheel farthest away the closer side of the wheel is moving to the right.)... 

A carbon atom in a ring can be a chirality center if it bears two different substituents and the path traced around the ring from that carbon in one direction is different from that traced in the other. The car bon atom that bears the methyl group in 1,2-epoxypropane, for exfflnple, is a chuality center. The sequence of groups is O—CH2 as one proceeds clockwise around the ring from that atom, but is CH2—O in the counterclockwise direction. Similarly, C-4 is a chirality center in limonene. 

If the order of decreasing precedence of the three highest ranked substituents appears in a clockwise sense, the absolute configuration is R (Latin rectus, "right," "correct"). If the order of decreasing precedence is counterclockwise, the absolute configuration is S (Latin sinister, "left"). 

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