Aluminum tubing

The most common technique for estimating thermal stability is called the Jet Fuel Thermal Oxidation Test (JFTOT). It shows the tendency of the fuel to form deposits on a metallic surface brought to high temperature. The sample passes under a pressure of 34.5 bar through a heated aluminum tube (260°C for Jet Al). After two and one-half hours, the pressure drop across a 17-micron filter placed at the outlet of the heater is measured (ASTM D 3241). 

A tube manufacturer wanted to investigate the possibility for on-line measurement, calculation and presentation of eccentricity values on aluminum tubes when drawn at high velocities. Based on our experience from development of tube inspection systems [1, 2] for off-line inspection of precision tubes, a project was formulated. The main specifications for the tube manufacturing are summarized below ... 

Figure 5. Measuring chamber with aluminum tube.

The project demonstrated that it is possible to measure and evaluate eccentricity of aluminum tubes at drawing velocities around 25 km per hour. Not all demands regarding small diameter tubes and thin walls were tested, and the calibration procedures were not finalized. Optimizing the system should make it possible to expand the limits... 

Work in connection with desahnation of seawater has shown that specially modified surfaces can have a profound effect on heat-transfer coefficients in evaporators. Figure 11-26 (Alexander and Hoffman, Oak Ridge National Laboratory TM-2203) compares overall coefficients for some of these surfaces when boiling fresh water in 0.051-m (2-in) tubes 2.44-m (8-ft) long at atmospheric pressure in both upflow and downflow. The area basis used was the nominal outside area. Tube 20 was a smooth 0.0016-m- (0.062-in-) wall aluminum brass tube that had accumulated about 6 years of fouhng in seawater service and exhibited a fouling resistance of about (2.6)(10 ) (m s K)/ J [0.00015 (fF -h-°F)/Btu]. Tube 23 was a clean aluminum tube with 20 spiral corrugations of 0.0032-m (lA-in) radius on a 0.254-m (10 -in)... 

Aluminum alloy (and in particular alclad aluminum) tubing is sometimes used in water service. The alclad alloy has a sacrificial aluminum-alloy layer metallurgically bonded to a core alloy. 

Copper, aluminum, stainless steel, nickel, or glass tubes bent into various shapes to fit the dimensions of the column oven provide the container for column packings [126]. Neither copper mor aluminum tubing is recommended as both metals are readily SKlditsd active, oxide-coated films formed on the inner walls promote decomposition or tailing of labile and polar solutes. Ptalnless steel is adequate for nonpolar samples but its catalytic activity precludes the analysis of labile solutes. Nickel, after acid passivation, and glass are the most inert column materials. 

Seams can be soldered, welded, cemented, treated with solutions, compound lined, dry, etc. Seams can be one piece drawn, stamped, or pressed. They may be drawn and wall ironed (DWI) or drawn and redrawn (DRD). Seams may be treated by impact extrusion (rigid and flexible, e.g., collapsible aluminum tubes are annealed). 

A suitable cannula was made by filing the ends of a 45-cm long aluminum tube of 2-mm internal diameter to points. 

Exhaled air Collection in aluminum tube adsorption on charcoal CS2 desorption GC/FID Not reported Not reported Cardona et al. 1996... 

Metals Metals are used as collapsible tubes and in aerosol containers. The most common metals in use are tin, aluminum, and lead. Tin is the most expensive, while lead is the cheapest. Laminates of tin-coated lead provide the appearance and oxidation resistance of straight tin at lower prices [89]. Tin is the most chemically inert of all collapsible tube metals. It offers a good appearance and compatibility with a wide range of products. Aluminum tubes provide the attractiveness of tin at relatively lower cost. Lead has the lowest cost of all tube metals and is widely used for nonfood products such as adhesives. However, with internal linings, lead tubes are used for such products as fluoride toothpaste. If the product is not compatible with bare metal, the interior can be flushed with wax-type formulations or with resin solutions. 

Formal Stability Studies — Long-term and accelerated (and intermediate) studies undertaken on primary or commitment batches according to a prescribed stability protocol to establish or confirm the retest period of a drug substance or the shelf life of a drug product. Impermeable Containers — Containers that provide a permanent barrier to the passage of gases or solvents (e.g., sealed aluminum tubes for semisolids, sealed glass ampoules for solutions). 

A typical example of frontal polymerization is the polymerization of methyl methacrylate (or an oligomer), placed inside a long aluminum tube 249 these tubes continuously dip into a bath with a liquid heated up to temperature of 70 - 80°C. The part at the tubes above the bath are cooled so that the reactive material does not polymerize. Polymerization shrinkage is compensated by continuous injection of a monomer or oligomer into the reaction zone. The appropriate combination of injection rate, velocity of tube movement through the reaction zone, and tube diameter are chosen according to experimental studies of the process. 

Test apparatus 2.6-m aluminum tube, 2 cm in diameter, marked into 10-cm segments with indelible ink) with fixed 50 x 50 x 1 cm Plexiglas side walls to prevent escape, elevated 20 cm from a cushioned floor. 

Specific relative humidity conditions are not necessary for products stored in impermeable container-closure systems that provide a permanent barrier to passage of moisture or solvent (e.g., liquids in sealed glass ampules and semisolids in sealed aluminum tubes). 

Three subenvironments within the low marsh (Figure 2) were sampled and analyzed (1) an evaporative or marsh panne, (2) the low marsh proper, and (3) a tidal creek. Sampling was performed (during March, 1988) using three inch aluminum tubing and a vibracoring unit (4). 

A whole laboratory can be readily served by one purification system if the purified gas is fed into a manifold with several outlets. Copper or aluminum tubing with Swagelok fittings and needle valves are convenient for this purpose. 

Separate out several small pieces of alcohol-damp primer precipitate totaling a farmer match head in volume (1 gram). If the mixture has dried, add a few drops of alcohol. Use only stain less-steel knife blades to handle the explosive. A third at a time, dump the chemical into the aluminum tube. Use a wooden dowel rod of the correct diameter to compress the mixture into acake at the bottom of the tube. 

After inserting a 21 /2-inch plastic straw segment into the aluminum tube piece, use long-nosed pliers to crimp one end of the tube securely. Keep the crimp short, neat, and pointed, as a clean point will facilitate insertion into the explosive mass later. 

The straw segment lining inside of the aluminum tube should now be crimped in at the bottom of the tube as well. The crimp must be as tight as possible, precluding drying air from getting in and chemical from exuding out. 

Slip one piece of insulation onto each side of the bridge wire assembly. These pieces act as added insulation so that the hot wire does not short out either through the plastic soda straw into the piece of aluminum tube or to each other above the notch. After the priming material is packed into the tube, the bridge wire assembly is inserted firmly down into the primer in the bottom of the tube, the wires turned down, and the tube sealed (more on this in Chapter 3). 

Builders who do not have access to aluminum tube or nickel chrome wire can use a standard PR-6 flashlight bulb. Carefully crack the glass away leaving the filament perfectly intact. Solder a wire lead to the back end and side of the bulb. Carefully place the intact filament into.the priming mixture. It Isn t as good as nickel chrome wire, but it will work. 

Leave the unfinished cap in the holder in a safe place where it cannot be disturbed. After 24 hours of curing, care fully place sufficient high-grade silicon caulk in the case to seal the bridge wires away from each other and the edges of the aluminum tubes. Thoroughly seal the end of the deto-... 

---