Quartz capillaries

Serizawa et al. (2002) studied experimentally, through visualization, the two-phase flow patterns in air-water two-phase flows in round tubes. The test section for air-water experiments consisted of a transparent silica or quartz capillary tube with circular cross-section positioned horizontally. The two-phase flow was realized through a mixer with different designs, as shown in Figs. 5.4 and 5.5. The air was injected into the mixer co-axially while water was introduced peripherally. 

DiGuilio and Teja have developed a two-wire technique to obtain absolute values of thermal conductivity. Quartz capillaries filled with liquid gallium served as insulated hot wires. They measured the thermal conductivity of the NaN0j-KN03 eutectic in the range 525-590 K with 1% accuracy. Radiation by the fluid was also accounted for. 

Similar findings were made by BASF in studies investigating an undisclosed gas-phase reaction in capillaries made of quartz, catalyst material and reactor-wall material [105]. The dimensions were chosen in such a way that they match the of surface-to-volume ratio of a fixed-bed reactor used previously for the same reaction. A quartz capillary shows no conversion, whereas reactor-wall material actually has a greater activity than the catalyst itself Hence BASF came to the, at first sight, surprising conclusion that in their production process it was the reactor wall, and not the catalyst, which catalyzes the reaction. The reactor wall was 70 times more active than the catalyst it needs a temperature increase of about 100 °C to have both at equal conversion. 

Flexible quartz capillary column, 0.2-mm i.d., 25-m length, coated with OV-101 (stationary phase)... 

Since the mass-transfer coefficient at a micropipette is inversely proportional to its radius, the smaller the pipette the faster heterogeneous rate constants can be measured. Micrometer-sized pipettes are too large to probe rapid CT reactions at the ITIES. Such measurements require smaller (nm-sized) pipettes. Nanopipettes are also potentially useful as SECM tips (see Section IV.D) because they can greatly improve spatial resolution of that technique. The fabrication of nanopipettes was made possible by the use of a micro-processor-controlled laser pipette puller capable of puling quartz capillaries [26]. Using this technique, Wei et al. produced nanopipettes as small as 20 nm tip radius and employed them in amperometric experiments [9]. 

Atomic oxygen was generated by photolysis of ozone which passed through a quartz capillary tube (0 2 mm and lehgth 60 mm), using the 253.7 nm line from a low-pressure mercury lamp (LI). 

Fatty acids were extracted following the above procedure. Fatty acids are analyzed by GC-MS. The GC used was a Perkin-Elmer 8600 fitted with flame ionization detector. An SE-54 quartz capillary column (30m) was used. The... 

A schematic diagram of an HPCE system is shown in Figure 4.54. The fused-quartz capillary is generally 50-75 cm long with an i.d. of 25-100 gm... 

Figure 6.19 Catalytic in situ reactor made of a quartz capillary, suitable for use at synchrotrons for the collection of EXAFS an XRD data. The scheme of the synchrotron beamline shows the positions of the mono-chromator, the ion chambers which measure the intensity of the X-rays before and after the sample, and the position-sensitive X-ray detector which records the XRD diffractogram (adapted from Clausen [44]).

Figure 5.8 A Debye-Scherrer powder camera for X-ray diffraction. The camera (a) consists of a long strip of photographic film fitted inside a disk. The sample (usually contained within a quartz capillary tube) is mounted vertically at the center of the camera and rotated slowly around its vertical axis. X-rays enter from the left, are scattered by the sample, and the undeflected part of the beam exits at the right. After about 24 hours the film is removed (b), and, following development, shows the diffraction pattern as a series of pairs of dark lines, symmetric about the exit slit. The diffraction angle (20) is measured from the film, and used to calculate the d spacings of the crystal from Bragg s law.

The use of glass and quartz capillaries is, in principle, not restricted to what nowadays are medium frequencies (400-600 MHz). This type of high pressure NMR equipment will certainly be further improved, mainly to study biological samples by high-field H NMR. To overcome the serious sensitivity problem inher-... 

Cockburn, J. J., et al. (2003). Crystalhzation of the membrane-containing bacteriophage PRDl in quartz capillaries by vapour diffusion. Acta Crystallogr. D 59, 538-540. 

GC and GC-MS Analyses. The concentrated extracts were analyzed on an Intersmat IGC 120F gas chromatograph with an ICR IB integrator using an SGE FFAP quartz capillary column (free fatty acid phase, 50 m x 0.22 mm i.d.) injection temperature 250°C, oven temperature 60°C for 8 min, operating temperature 230°C (temperature gradient 2°C/min). 

Column type quartz-capillary column Column length 22 m (int. diameter 0.4 mm) ... 

Non-catalytic reaction pathways and rates of reaction of diethyl ether in supercritical water have been determined in a quartz capillary by observing the liquid- and gas-phase XH and 13C NMR spectra.37 At 400 °C, diethyl ether undergoes, competitively, proton-transferred fragmentation and hydrolysis as primary steps. The former path generates acetaldehyde and ethane and is dominant over the wide water density range up to... 

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