Twist measurement

If this unit of twist measurement is substituted for the horizontal axis in Figure 1, then it is possible to determine the optimum twist levels for maximum yam strength for any size yam of a given fiber composition. 

The circular dichroism of polynucleotides at 275 nm is a linear function of both the helix winding angle and the base pair twist. Measurement of CD specfra on large polynucleotides or large molecular aggregates... 

K torsional constant of wire, Nm L fiee length of test piece, m a angle of twist measured, "... 

Twist Measure of spiral turns per unit length given to yarn or strand hold constituent filaments together—S twist if spirals slope in same direction as middle portion of letter S, Z twist if spirals slope in same direction as middle portion of letter Z. 

Figure Al.4.4. The definition of the Euler angles (0, ( ), x) that relate the orientation of the molecule fixed (x, y, z) axes to the (X, Y, Z) axes. The origin of both axis systems is at the nuclear centre of mass O, and the node line ON is directed so that a right handed screw is driven along ON in its positive direction by twisting it from Z to z through 9 where 0 < 9 < n. ( ) and x have the ranges 0 to In. x is measured from the node line.

For phase encoding the phase twist is most connnonly varied by incrementing in a series of subsequent transients as tiiis results in a constant transverse relaxation attenuation of the signal at the measurement position. The signal intensity as a fiinction of G is... 

Signal Transmission and Conditioning. A wide variety of physical and chemical phenomena are used to measure the many process variables required to characteri2e the state of a process. Because most processes are operated from a control house, these values must be available there. Hence, the measurements are usually transduced to an electronic form, most often 4 to 20 m A, and then transmitted to the control house or to a remote terminal unit and then to the control house (see Fig. 6). Wherever transmission of these signals takes place in twisted pairs, it is especially important that proper care is taken so that these measurement signals are not cormpted owing to ground currents, interference from other electrical equipment and... 

The MacMichael viscometer is probably the most straightforward rotatioaal viscometer. The outer cup rotates and the inner cylinder is suspended from a torsion wire. The drag on the inner cylinder is measured as degree of twist on the wire. Wires of different stiffness are available, and the maximum viscosity is ca 10 mPa-s. The shear rate range is limited, ca 2-12, but with modification, higher shear rates can be attained. The iastmment is best... 

Transverse Dimensions or Fineness. Historically, the quantity used to describe the fineness or coarseness of a fiber was the diameter. Eor fibers that have irregular cross-sections or that taper along their lengths, the term diameter has no useful meaning. Eor cylindrical fibers, however, diameter is an accurate measurement of the transverse dimension. Though textile fibers can be purchased in a variety of cross-sectional shapes, diameter is stiU a useful descriptor of the transverse dimension. Eiber diameter is important in determining not only the ease with which fibers can be twisted in converting them to yams, but also fiber stiffness, ie, fabric stiffness, and, alternatively, fabric softness and drapeabiHty. 

Twist. Twist (23) is measured in numbers of turns per unit original length, turns per inch, cm, or meter. 

The influence of skin effects in a multi-core cable is almost the same as that of a multiphase busbar system, discussed in Sections 28.7 and 28.8. However, unlike a busbar system, the resistance and inductive reactance for various sizes of cables can be easily measured and are provided by leading manufacturers as standard practice in their technical data sheets. To this extent, making an assessment of skin effects in cables is easy compared to a busbar system. Since all the phases in a cable, of a 3-core or 3 72-core are in a regularly twisted formation throughout the length of the cable, they represent the case of an ideal phase transposition (Section 28.8.4(3)) and almost nullify the effect of proximity. 

A typical screwdriver has a shaft and blade made of a high-carbon steel, a metal. Steel is chosen because its modulus is high. The modulus measures the resistance of the material to elastic deflection or bending. If you made the shaft out of a polymer like polyethylene instead, it would twist far too much. A high modulus is one criterion in... 

This measurement ean be aeeomplished by using a meehanieal system or various types of eleetronie systems. All of these systems are expensive and in many eases require repeated ealibration. The meehanieal system (Figure 19-14) is a three-gear, phase-related system whieh measures the displaeement between two gears and the proportionate shaft twist. A third gear is situated so that any variations other than shaft twist will oeeur in the first two gears. This signal is used to eliminate errors eaused by these variations. 

Temperature Measurement shift. Measurement not representative of process. Indicator reading varies second to second. Ambient temperature change. Fast changing process temperature. Electrical power wires near thermocouple extension wires. Increase immersion length. Insulate surface. Use quick response or low thermal time constant device. Use shielded, twisted pair thermocouple extension wire, and/or install in conduit. 

Repeated twisting of the spindle s tube or the solid shaft used in jackshafts results in a reduction in the flexible drive s stiffness. When this occurs, the drive loses some of its ability to absorb torsional transients. As a result, damage may result to the driven unit. Unfortunately, the limits of single-channel, frequency-domain data acquisition prevents accurate measurement of this failure mode. Most of the abnormal vibration that results from fatigue occurs in the relatively brief time interval associated with startup, when radical speed changes occur, or during shutdown of the machine-train. As a result, this type of data acquisition and analysis cannot adequately capture these... 

Shear stress-strain data can be generated by twisting (applying torque) a material specimen at a specified rate while measuring the angle of twist between the ends of the specimen and the torque load exerted by the specimen on the testing machine. Maximum shear stress at the surface of the specimen can be computed from the measured torque that is the maximum shear strain from the measured angle of twist. 

Certain materials may be weak in shear, and for these it is appropriate to measure their strength by torsion tests. For such tests, the material is fabricated into a rod of circular cross-section, and twisted about its longitudinal axis. The angle of twist is proportional to the shearing strain, and the... 

Stacked together along the a-axis. The long molecular axes are tilted by 13° within the layers. By Raman spectral measurements Tashiro et al. found that the biphenyl group of the compound has a twisted structure in the liquid crystalline state as well as in the a-form. 

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