Cold gas, jet

Cold "Burns" (8). Direct contact of body tissue with liquid hydrogen for a short time may result in no damage because the boiling liquid will be separated from the skin by a layer of vapor and because hydrogen has a relatively low heat of vaporization. Cold gas jetting onto the skin can result in a high heat flux sufficient to cause freezing. The body can tolerate heat fluxes of 30 Btu/hr-ft without discomfort a flux of 740 Btu/hr-ft will freeze facial tissue in about 10 seconds. A... 

Fig. 20.3. The upper diagram shows the ion beam profiles of the Cl l) and OoH.j parent ions and Ar+ in the z-direction. The ion signal was measured as a function of the voltage on the z-deflector pair. The electron energy was set to 100 eV. In the lower diagram the initial ion kinetic energy distributions were calculated from these z-profiles and compared to Ar that has been introduced as a cold gas jet...

FIGURE 5.9 Phase-coated thermal modulators using a rotating heater (a), moving cold zone (b), and cold gas jets (c) to modulate the concentration of the sample vapor entering the device. For configuration (c), the jets are turned on and off alternately to modulate the sample vapor concentration. 

As the ion funnels are made of stacked ring electrodes, in both of the funnels efficient pumping is expected between the electrodes. Due to the adiabatic expansion through the orifice between the two pressure stages the expanded gas cools down, and this gas jet tends to conserve its integrity for a relatively long time (and distance) in the second ion funnel. It does not easily dissipate—despite the efficient pumping. This cold gas jet enables the measurement of ion mobility in the ion funnel with a sufficient resolution. 

Experiment 99. — Attach a pointed glass tube (see Exp. 57 c)) to the rubber tube connected with the gas jet and lower a small flame of illuminating gas into a cold, dry bottle. Observe the most definite result. Remove and extinguish the flame, add a little lime water, and shake. Describe the result. What do these two observations show about the composition of the main constituents of illuminating gas ... 

Because of the instability of S at room temperature the quenching of the sulfur melt has to be very rapid and efficient. Different authors have used ice water [20-22], liquid air [23], or sheets of glass [19] or metal [19, 24] onto which the melt was blown by a strong jet of cold gas to produce either a thin film or small particles. Because of the low heat conductivity of elemental sulfur the quenching in water is insufficient and water is not even inert chemically towards hot sulfur. The quenched melt has to be extracted by CS2 at... 

P.W. Schenk equiUbrated liquid sulfur in an aluminum oven and allowed the melt to flow in a thin stream from the oven through a valve in the bottom. Using a jet of cold gas to blow the melt against a sheet of glass (P.W. Schenk) or copper or aluminum metal (Koh and Klement) the authors tried to rapidly quench the melt as a thin layer. In some experiments J. Schenk used liquid air to quench the melt, a coolant which is to be preferred over water since it yields very small particles of sulfur which are efficiently quenched. After extraction with CS2 at 20 °C the S content was determined as insoluble residue. 

A gas jet (Bunsen s, if possible) boils the water in the saucepan the ascending steam is condensed on the lower surface of the steamer, runs down to the point of the wire, down the pipe into the bottle. A small jet of cold water keeps b cool. 

The processes of metal cluster formation in a carrier gas jet and their modification on condensation at the cold surface are rather complex, hr the experimental setup the... 

Chapter II, Blast Wave Reflections and Interactions, presents a number of articles on the interaction of blast waves with real surfaces. For example, Rayevsky et al. have studied the normal reflection of a blast wave from a rigid wall coated with polyurethane foam. They found that, contrary to intuition, the foam layer significantly increased the peak reflected pressure on the wall. Lyakhov and coworkers report on shock reflections from a body with a hot or cold gas layer. Kuhl et al. present a detailed simulation of a double-Mach reflection from a dusty wall. By using a nondiffusive numerical scheme and adaptive mesh refinement, they were able to directly calculate the mixing in the unstable wall jet and dusty boundary layer flow. Similarity coordinates were used to average the fluctuating flow and thereby determine the dusty boundary layer profiles. Shepherd et al. report on the repeated reflections of detonation-driven blast waves in containers. 

FIGURE 3.8 Schematic illustration of an ion funnel at the pressure P2 into which a gas from the pumping stage at pressure enters through a Laval nozzle instead of a simple orifice. The entering gas expands and forms a cold supersonic jet that... 

The alternative technique to TIRES is transient infrared transmission spectrometry (TIRTS). This technique is analogous to TIRES, but instead of the sample being at ambient temperature and being heated by the gas jet, the sample is above the ambient temperature and is cooled by a narrow jet of cold helium. Were the sample... 

In the mixed core, illustrated in Fig. 8-1, the inlet and outlet are concentric at the top of the sphere. The inlet jet coincides with the vertical axis of the sphere and is broken up when it hits the bottom surface. Except for the cold central jet, the bulk of the core is at outlet temperature. The velocity of eddies is great enough so that the gas bubbles travel along with the liciuid. The pressure drop is about 1.0 to 1.5 inlet-velocity heads. The core-tank surface is maintained at a temperature very close to that of the core fluid l)y the high turbulence. 

Relatively thick Al coatings can be deposited onto metal and other selected substrates using cold gas sprayed (or cold spray) coatings. Cold spray accelerates small particles, typically <50 pm diameter to high velocity (>700m s" ) using a supersonic gas jet. The impacting... 

In general, plants using SO2 gas derived from metallic sulfides, spent acids, or gypsum anhydrite purify the gas stream before drying it by cold, ie, wet, gas purification. Various equipment combinations including humidification towers, reverse jet scmbbers, packed gas cooling towers, impingement tray columns and electrostatic precipitators are used to clean the gas. 

Initially a molten tube of plastic called the Parison is extruded through an annular die. A mould then closes round the parison and a jet of gas inflates it to take up the shape of the mould. This is illustrated in Fig. 4.21(a). Although this process is principally used for the production of bottles (for washing-up liquid, disinfectant, soft drinks, etc.) it is not restricted to small hollow articles. Domestic cold water storage tanks, large storage drums and 2(X)... 

The plasma jet can be cooled rapidly just prior to coming in contact with the substrate by using a blast of cold inert gas fed into an annular fixture. Gaseous boron or phosphorus compounds can be introduced into the gas feed for the deposition of doped-semiconduc-tor diamond. 

Most of the generated vapour is condensed in spray condensers which are equipped with circulation pumps and an EG cooler. The vapour that is still uncondensed is withdrawn from the gas phase with the help of a vapour jet which is located down-stream behind the spray condenser and generates the necessary vacuum in the reaction zone. The most critical part of the spray condenser system is the end of the pipe leading the vapour from the prepolycondensation reactors and the finishers into the spray condenser. The transition from a hot to a cold environment causes deposition of solid material onto the cold walls which has to be removed manually or by means of a mechanical scraper. 

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