Spiral trap

Separation of a noncondensible gas like CO or H2 from the solvent is effected simply by carefully opening the reactor (at 25°) to a cold (-196°) spiral trap (of approximate volume 100 mL). After completion of vacuum transfer of acetonitrile into the sprial trap, the volatile gas is Toepler pumped (10) into the calibrated region of the vacuum line until further strokes of the pump give no change in pressure. The number of mmoles of gas is determined from the calibration of the vacuum line. 

Flame Arrestors and Explosion Reliefs. The flame trap is constructed of strips of corrugated and flat steel ribbon wound in a spiral. It breaks up a flame in the very small passages between the corrugations where the flame is quenched and extinguished. 

As a thickener (as opposed to a gel), it is amylose that has the main function. The long water-soluble chains increase the viscosity, which doesn t change much with temperature. Amylose chains tend to curl up into helixes (spirals) with the hydrophobic parts inside. This allows them to trap oils, fats, and aroma molecules inside the helix. 

The Orbitrap. The Orbitrap analyzer, [26] invented by Alexander Makarov, has been defined by the company that commercially produces it as the first totally new mass analyzer to be introduced to the market in more than 20 years . Its name recalls the concept of trapping ions. Indeed, ions are trapped in an electrostatic field produced by two electrodes a central spindle-shaped and an outer barrel-like electrode. Ions are moving in harmonic, complex spiral-like movements around the central electrode while shuttling back and forth over its long axis in harmonic motion with frequencies... 

A scroll vacuum pump uses two interleaved Archimedean spiral-shaped scrolls to pump or compress gases (see Fig. 1.9). One of the scrolls is fixed, while the other orbits eccentrically without rotating, thereby trapping and compressing gases between the scrolls and moving it towards the outlet. 

FIGURE 4-10 Myelin formation in the peripheral nervous system. (A) The Schwann cell has surrounded the axon but the external surfaces of the plasma membrane have not yet fused in the mesaxon. (B) The mesaxon has fused into a five-layered structure and spiraled once around the axon. (C) A few layers of myelin have formed but are not completely compacted. Note the cytoplasm trapped in zones where the cytoplasmic membrane surfaces have not yet fused. (D) Compact myelin showing only a few layers for the sake of clarity. Note that Schwann cell cytoplasm forms a ring both inside and outside of the sheath. (Adapted with permission from Norton, W. T. The myelin sheath. In E. S. Goldensohn and S. H. Appel (eds), Scientific Approaches to Clinical Neurology. Philadelphia Lea Febiger, 1977, pp. 259-298.)... 

After the third extraction, we measure the radon and its yield by adding several cc STP of carrier Ar to the melt water with He to 1.3-atm pressure and allow the radon to build up for 4 days. We also replace the spiral glass C02 trap with a charcoal trap to insure the collection of the carrier Ar with the radon. We then He-purge the water and collect the Rn with the carrier Ar on the charcoal at liquid air temperature. The Ar plus Rn is recovered from the charcoal at 300 °C purified over hot Ti and counted in a proportional counter. 

When substances adsorbed on aerosol particles are to be determined, the gas is passed through a membrane or other filter and the filter is dissolved in or extracted with a suitable solution. An interesting method is used for determination of fluoride adsorbed on atmospheric aerosols [87]. The particles are trapped on a filter impregnated with citric acid and heated to 80 °C, while the fluorides pass through and are absorbed in a thin layer of sodium carbonate in a spiral absorber. The sodium carbonate is periodically washed with a sodium citrate solution, in which solution the fluoride is then determined, and the absorption layer regenerated. 

To increase the ionization probability, a homogeneous weak magnetic field is used to keep the electrons on a spiral path. At the end of the ionization chamber, electrons are collected in a positively charged trap, where the electron current is measured and kept constant by the emission regulator circuitry. 

The realization that tubules may be formed on temperature reduction of polymerized SUVs, prepared from polymerizable diacetylenic phosphatidylcholines (21 where n = 7-16 and m = 5-11), represented a major breakthrough in obtaining the desired supramolecular structure [355-360]. In the initial experiments, 0.4- to 1.0-pm-diameter and 10- to 1000-pm-long tubules were prepared by the gradual lowering of the temperature (to about 38 °Q of 21 (m = 8, n = 9) SUVs [358]. The walk of the tubules had thickness of 10-40 nm and were coated by spiral ripples and helical bilayer strips. Many tubules contained trapped SUVs. Polymerization of the acetylenic moieties greatly enhanced the mechanical and thermal stabilities of the tubules [355-360]. 

Fig. 7.4. Mercury pickup devices, (a) Vacuum pickup device. Collected mercury is trapped in the flask for recycling or disposal. (b) Amalgamated copper wire pickup device. The wire is first cleaned in nilric acid, then dipped into a solution of mercuric nitrate to give a thin coating of mercury. Droplets of mercury readily cling to the spiral and may be shaken off into a mercury waste container.

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