Working principles

The motion of an ion in the x- and y-directions is described by using a quadratic equation that is commonly known to mathematicians as the Mathieu equation  

Back pressure or die pressure fluctuation is one of the most serious problems and therefore screw design is an important parameter in the stability of the extrusion process [12,13]. 

Polymer material is fed into the co-rotating twin-screw extruder and is conveyed in a loosely packed form in a normally partially filled material conveying section. In the screw, barrier elements such as reverse screw element(s), and/or reverse/neutral kneading hlock(s), are installed 

A certain amount of energy has to be provided to heat and melt the materials above their transition temperature in the extruder. The energy required for melting can be approximately calculated from the typical specific enthalpy of each polymer. The energy is supplied either by heat transfer through the heated barrel walls or by dissipation, frictional heat, and mechanical energy supplied by the extruder drive. 

In the solids-conveying and melting sections in single-screw extruders, the solid particulate assembly is normally treated as a solids plug . This assumption can be nsed to predict the pressurisation of polymer solids in the solids-conveying section of single-screw extruders with different screw geometries and material properties. 

The complexity of the flow in twin-screw extruders, as well as the large number of parameters and interrelated variables that affect the flow, make this process difficult to understand, control, and optimise. 

As mentioned above, the gain medium of every kind of laser is associated with an optical resonator, whose structure will be detailed below. The simplest Fabry-Perot-type resonator comprises only two mirrors, between which the gain medium is situated. The feedback structure imposes two basic properties upon the oscillating laser field. It defines not only the allowed resonant frequencies within the gain medium s emission spectrum but also the spatial characteristics of the laser beam. 

To achieve a sustained oscillation in a laser, amplification in the gain medium must at least balance out with the optical loss during each round-trip of the cavity. Therefore, when the pump rate increases beyond a threshold value, an intense coherent laser beam is generated whose power rises linearly with the excess pump rate. At low pumping rates, the excitations in the gain medium are radiated in all directions as spontaneous emission. 

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Membranes are also used to separate gases, for example, the production of N2 and O2 from air and the recovery of hydrogen from ammonia plant purge gas. The working principle is a membrane that is chemically tuned to pass a molecular type. 

Figure 4-33. Working principle of thrust transmission shown on a single helical precision gear.

Smokeless Steam Inspirating Air Coanda effect nozzles are used to inspirate air into the mixing chamber. Claim high efficiency of steam use. Claim low steam noise. Complex nozzles are a high-cost component. Brochure shows much R D back-up of basic design, in marked contrast to those of other vendors. Coanda effect is well understood and widely used, therefore working principle is well established. 

The working principle of the polymer light-emitting electrochemical cell is shown in Figure 9-23 ... 

FIGURE 35.42 Illustration of the outer roll bending working principle. 

Adequate techniques to accurately and selectively detect concentration levels are available, but are mostly expensive, slow, and complex. Cheaper sensors are available, but the working principle is usually not very selective. A wealth of different sensing techniques exists where typical sensor principles rely on changes in... 

The perceptron-like linear networks were the first networks that were developed [3,4], They are described in an intuitive way in Chapter 33. In this section we explain their working principle as an introduction to that of the more advanced MLF networks. We explain the principle of these early networks by means of the Linear Learning Machine (LLM) since it is the best known example in chemistry. 

FIGURE 6.1 Diagram of AFM work principle. Reprinted with permission from Liu and... 

For multi-analyte and/or multi-matrix methods, it is not possible to validate a method for all combinations of analyte, concentration and type of sample matrix that may be encountered in subsequent use of the method. On the other hand, the standards EN1528 andEN 12393 consist of a range of old multi-residue methods. The working principles of these methods are accepted not only in Europe, but all over the world. Most often these methods are based on extractions with acetone, acetonitrile, ethyl acetate or n-hexane. Subsequent cleanup steps are based on solvent partition steps and size exclusion or adsorption chromatography on Florisil, silica gel or alumina. Each solvent and each cleanup step has been successfully applied to hundreds of pesticides and tested in countless method validation studies. The selectivity and sensitivity of GC combined with electron capture, nitrogen-phosphorus, flame photometric or mass spectrometric detectors for a large number of pesticides are acceptable. 

Due to the different working principles of WDXRF and EDXRF, the applications differ strongly (Table 8.43). Simultaneous WDXRF with ten channels (elements) and increased sensitivity for the low atomic number elements (e.g. a few ppm of phosphorous in a low atomic number matrix) has been used for QC of polymer granules [252], To detect elements at trace levels (ppm-ppt), generally the special XRF modes, mainly EDXRF techniques, are applied like TXRF, SR-XRF or pXRF. Detection limits with SR-XRF are now at the attogram level. 

We confine ourselves here to a brief description of the capabilities and working principles of the instrument, referring the reader for details to the... 

The working principle of LAPS resembles that of an ion-selective field effect transistor (ISFET). In both cases the ion concentration affects the surface potential and therefore the properties of the depletion layer. Many of the technologies developed for ISFETs, such as forming of ion-selective layers on the insulator surface, have been applied to LAPS without significant modification. 

Additionally, using the filling and absorption times established with the aid of electronics, the quantity of laundry or type of textile can be registered and the wash and rinse program can be modified as appropriate. The working principle as defined by water level in relation to process time is shown in the upper part of Fig. 3.6. 

Measuring body temperature is important for the detection of disease and assessment of the response to treatments. The first thermometer was developed by Galileo in 1603. Thermometers for measuring body temperature have been in use since about 1870. The first measurements taken were axillary, and later oral and rectal measuring methods were introduced. The working principle of those thermometers, the expansion of matter by temperature increase, is still used for body temperature measurement in mercury-in-glass thermometers. Electronic thermo-... 

Fig. 4.8 Schematic illustration of the working principle of the dynamic bubble pressure method. If the bubble radius equals the capillary radius, maximum pressure is detected. The pressure minimum occurs on bubble detachment.

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