Optical comparator

Using the electron density map a three-dimensional model of the protein can be built. For years, the customary procedure was to construct a model at a scale of 2 cm = 0.1 ran using an optical comparator, but... 

The area of a polished electrode (taken to be the projected or geometric area in most voltammetric experiments at times > 1 s) usually is measured directly or electrochemically. If the electrode is of regular geometry, such as a disk, sphere, or wire of uniform diameter, its characteristic dimensions can be measured by use of a micrometer, optical comparator, or traveling microscope and the area calculated. 

Meniscus Regression. The meniscus regression method is comparable to the weight loss method in its simplicity and rapidity. The increase in the length of the void space between the open end of the hollow fiber and the meniscus of the column of liquid is measured periodically using a Wilder Varibeam optical comparator which has been described by Weatherston et. al. (3). Since this instrument can also be used to measure tFe internal diameter of the fiber, the volume and therefore the weight of material lost can be calculated as a function of time. 

Figure 8F-3 Optical comparator, (a) An optical fiber that splits into two branches carries light from a light-emitting diode (LED) through sample and reference wells in a microtiter plate holder. In the comparison mode, a standard containing the threshold level of analyte (aflatoxin) is placed in one of the reference well holders. The samples containing unknown amounts of the analyte are placed in the sample well holder. If the sample contains more aflatoxin than the standard (b), the sample well absorbs less light at 650 nm than the reference well. An electronic circuit lights a red LED to indicate a dangerous amount of aflatoxin. If the sample contains less aflatoxin than the standard (c), a green LED is lit.

There is now also equipment that uses electronic gauging, computer controller optical comparators and video image analysers to measure component dimensions automatically. Once this type of equipment is correctly calibrated and programmed, it can relieve pressure on staff operatives while providing an enormous increase in accuracy, statistical data and overall value of examinations. It is only to be expected that it suffers the major disadvantage of being expensive, and probably outside the normal laboratory budget. 

The notched tensile test specimens used in this investigation are shown in Fig. 1. For most tests, the notched specimens were used with a notch concentration factor of Kt — 6.3, as determined after Neuber [ ]. In one series of tests a of 15.0 was used. Each notched specimen was checked with a Jones Lamson optical comparator at 50 x. Only those specimens with notched dimensions within the specified tolerances were tested. 

A newer development in this area is the production of retortable, multilayer, blow-molded containers that incorporate polycarbonate as the tough outer layer, with EVOH or poly(vinyiidene chloride) (PVDC) as the barrier, and polypropylene (PP) as the food contact layer. The advantages of polycarbonate are its light weight, improved heat stability, and good optics compared to the polyolefins that are normally used. 

The aluminum alloys used in this investigation and their history and chemical analyses are listed in Table I. The materials were tested in the "as-received" condition without further heat treatment or working. The tensile specimens used in this investigation are shown in Fig. 1. All tensile specimens were inspected and individually measured for area determination. Notched specimens were inspected and measured by means of an optical comparator and all specimens out of tolerance were rejected. The stress concentration factor, as determined by [(V2 width between notches)/(radius of the notch) s 6.3 with tolerance limits of 5.7 to 7.1. 

Linear Measurement (micrometers, dial calipers, surface plates, optical comparators, scientific rotation)... 

The PSD-SE-Method requires, compared to the SE-Method, a large illumination beam, in which several measurement beams, with almost constant intensity, can be arranged next to each other. For this purpose, significantly larger transmitter optic, compared to the SE-Sensor, is necessary. Since the one-piece sensor concept, described earlier, requires the insertion of the sensor modules in the process, and larger objects have a larger impact on the process, the PSD-SE-Sensor is constructed as a two-piece sensor (Fig. 12.19). 

The chemistry of the yohimbines forms an excellent example of the value of studying related alkaloids together and Chart 5.4 which illustrates this and its obvious conclusions, can be checked against Table 5.1. The absolute stereochemistry of the yohimbines has been looked at by most of the optical comparative methods. A purely chemical proof depends on the conversion of yohimbine into a seco base which in turn has been related to cinchonine infra). 

Precision techniques are required to measure the finished products, including CNC coordinate measuring machine (CMM) capability with associated CAD/CAM features, laser micrometers, form-scan geometry gauge, optical comparators, and other digital gauges. 

In order to obtain the as extruded geometries, prior to each extrusion being tested in the Instron, the part was placed on a 1 OX optical comparator and a sketch was made of the part. This sketch was then used to create the CAD model used in the FEA program. 

---