Spindle capillary

Spindle capillary (Novotny type) is manufactured from a classical cylindrical capillary. The length and the diameter of the upper narrow, cylindrical part of the capillary controls the mercury flow. The inner space in the lower part has the shape of an unsymmetrical spindle with its longer end pointing downwards. This shape of the inner part of the capillary prevents penetration of the solution into the orifice the capillary exhibits then... 

In 1903 KuCera attempted using it for measuring surface tension of mercury in solutions his little success was due to the scarce knowledge of electrochemistry in his time. By the spontaneous renewal of its surface the DE paved the way for polarography its unique properties were utilized also in other physico-chemical measurements. As the main instrument in polarography, the DE went through various modifications and other renewed electrodes have been derived from it. The use of a special spindle capillary led to introduction of a highly sensitive method of electrocapillary measurements with the DE, 75 years after KuCera s attempt. 

The drops growing from a spindle capillary are more stable than those from cylindrical or conical capillaries, and their reproducibility is very high. These factors led to the development of the "controlled convection" method of electrocapillary measurements (53-53). With a drop-time of, say, 100 s, the reproducibility under constant conditions is better than 0.02 s, i.e. 0.02 The stability of the drop allows the solution to be stirred over 90 % of the drop life without affecting its reproducibility, providing... 

The spindle capillary provides a multipurpose renewed mercury electrode, which utilizes all the features of the dropping electrode. It should consist of a stand containing the necessary electronic controls, with an appropriate, safely closed reservoir of mercury, an exchangeable cell, and an electrode holder into which special capillaries can be easily fitted according to the purpose of the measurement. In addition to other accessories, a wide selection of capillaries of various parameters should be readily available, the less usual ones obtainable on order. 

As demonstrated by the example of the spindle capillary, the development of the dropping electrode is far from exhausted. By its origin it is predestined for research of interfacial electrochemical processes, where it can render invaluable services in analyzing or effectuating complex reactions at molecular or macro-... 

The seal is made by cutting 1-cm diameter tubing to give one piece with a square end. Near the end of the other piece a spindle is drawn. The shoulder of the spindle is heated in a small hot flame so that it thickens, and then, with a fairly cool flame, the spindle beyond the shoulder is drawn out to a fine capillary about 1 mm diameter. This is heated in a very cool flame and bent first one way and then the other, as m Figure 47, II. The end is finally sealed off. The tip thus prepared is inserted into the square end of the other piece of tubing, as in Figure 47, /, and a joint is made by directing a small flame at... 

In order to extract small fluid samples from the reaction cell at high temperatures, a capillary with a tip of sintered alumina, can be introduced sidewise into the center of the reaction cell. The samples pass into a section of stainless steel capillary between two high pressure valves mounted on a heated metal block. The capillary section serves as a pipette from which liquid and gaseous components can be extracted for analysis. Another method is, to use a small spindle press. By turning it back very slowly, samples can be sucked out steadily from the reaction cell. 

Measuring Viscosity Several common methods are available for measuring viscosity. Two very common ones are the use of capillary tubes such as Ubbelohde, Ostwald, or Cannon-Fenske viscometer tubes and the use of a rotating spindle such as the Brookfield viscometer. 

Aggressive angiomyxoma (AAM) is a peculiar neoplasm of the pelvic and perineal soft tissues that most commonly affects women. It is composed of loosely arranged, bland spindled to stellate cells embedded in a myxoid matrix punctuated by numerous venule- and capillary-sized blood vessels reminiscent of myxoid liposarcoma (Fig. 4.8). The vascular pattern of AAM lacks the arborizing appearance that is seen in some overtly malignant myxoid tumors. Some morphologic and immunophenotypic features of aggressive AAM also are shared in part by intramuscular myxoma. 

A satisfactory method of bonding these components is to assemble them first and then apply a low-viscosity adhesive which will flow into the space between the spindle and the knob by capillary action. 

Once a suitable crystal has been obtained, the structure of a molecule of moderate size can often be determined in a day or so. The crystal is mounted on a glass fiber (or in a glass capillary containing an inert gas, if the substance reacts with air) and placed on a pin or spindle within the circular assembly of the x-ray diffractometer (Figure 11.50). The crystal and x-ray detector (placed on the opposite side of the crystal from the x-ray tube) rotate under computer control, while the computer records the intensities and angles of thousands of x-ray reflection spots. After computer analysis of the data, the molecular structure is printed out. 

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