Tube inflation

Figure 9 Thickness of a protein, (a) The structure of the B1 immunoglobulin-binding domain of streptococcal protein G is visualized as a thin tube, (b) View of the same tube inflated to its thickness (i.e., to a radius above which the tube ceases to be smooth, or shows self contact). Note that no free space exists between consecutive turns of the helices. Figure 9a drawn with MOLSCRIPT and 9b with VMD. ...

Figure 7.4.6 shows some transient planar viscosity data obtained by tube inflation. At short times (small strains) aii the ma-... 

Blown Film. The blown or tubular film process provides a low cost method for production of thin films (Fig. 3). In this process, the hot melt is extmded through an aimular circular die either upward or downward and, less frequently, horizontally. The tube is inflated with air to a diameter... 

Many articles, bottles and containers in particular, are made by blow moulding techniques of which there are many variations. In one typical process a hollow tube is extruded vertically downwards on to a spigot. Two mould halves close on to the extrudate (known in this context as the parison ) and air is blown through the spigot to inflate the parison so that it takes up the shape of the mould. As in injection moulding, polymers of low, intermediate and high density each find use according to the flexibility required of the finished product. 

In the tubular process a thin tube is extruded (usually in a vertically upward direction) and by blowing air through the die head the tube is inflated into a thin bubble. This is cooled, flattened out and wound up. The ratio of bubble diameter to die diameter is known as the blow-up ratio, the ratio of the haul-off rate to the natural extrusion rate is referred to as the draw-down ratio and the distance between the die and the frost line (when the extrudate becomes solidified and which can often be seen by the appearance of haziness), the freeze-line distance. 

Although plastic sheet and film may be produced using a slit die, by far the most common method nowadays is the film blowing process illustrated in Fig. 4.20. The molten plastic from the extruder passes through an annular die and emerges as a thin tube. A supply of air to the inside of the tube prevents it from collapsing and indeed may be used to inflate it to a larger diameter. 

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)... 

Solution It is necessary to derive an expression for the inflation time. Referring to Fig. 5.22 where R is the radius of the inflated tube at any time, /, and hi is the wall thickness at this time, then a force balance on the shaded element gives (for unit length). 

The inner liner forms the vital internal membrane which holds the inflation medium at an elevated pressure within the structure of the tire. In early days the liner was a separate tube of natural or butyl, or more particularly, XIIR compound as an integral part of the tire structure. Adhesion levels of butyl compounds can be critically low requiring an insulating or barrier layer of an NR compound to act as an interface between the liner and the casing. 

They are then forced through a narrow die to form a hollow tube called a parison. A chilled mold is then clamped around the parison and inflated from the inside by air. The air pressure presses the parison against the mold, and it hardens in the shape of the mold. The mold then opens and ejects the HDPE bottle. The bottle is then trimmed and conveyed to the milk filling station. The waste plastic is ground for reuse. GHG emissions associated with the embodied energy of the packaging machinery may be calculated but typically fall near the 1% cutoff line and can be excluded (Cashman et ah, 2009). 

Balloon tamponade involves the application of direct pressure to the area of bleeding with an inflatable balloon attached to a nasogastric tube. It is an option for patients in whom drug therapy and band ligation fail to stop variceal bleeding. Balloon tamponade is used only when other methods have failed. Once the direct pressure of the balloon is removed, rebleeding often occurs, so balloon tamponade is only a temporary measure prior to more definitive treatment such as shunting.11... 

In pneumatic tyre manufacture, the heavy mbber tube to which is admitted the inflation medium... 

The part of the pneumatic tyre assembly which holds the inflation air under pressure. It is protected by the outer cover or tyre and, in giant sizes, protected from rim damage by the flap . Inner tubes are primarily made of butyl rubber. Some cycle tubes still use NR. See Tubeless. Inorganic... 

An assembly of outer cover (or tyre) fitted with an inner tube and mounted on a metal rim or wheel, the inner tube is inflated with air under pressure which supports the load of the vehicle. In the tubeless tyre no separate inner tube is fitted, the outer cover itself being so constructed as to retain the inflation air. 

Applied to a pneumatic tyre with no separate inner tube. An air-impermeable lining, usually of a halogenated butyl, is applied to the inside of the casing. The bead construction is such as to ensure an airtight lit on the wheel rim. Inflation is done through a valve fitted directly into a valve hole in the rim. 

To transfer the liquid, a small overpressure is created in the dewar from which the liquid is to be transferred. A special care must be taken when transferring LHe into either a warm dewar or a partially filled dewar to avoid waste of liquid. If the dewar is warm (77 K), a slow initial transfer reduces the liquid consumption. If liquid is already in the dewar, the risk of inflating a warm stream of He gas must be avoided. The simplest transfer tubes are U shaped. There are flexible and demountable transfer tubes. 

Angioplasty may take between 30 minutes to 3 hours to complete. It begins with a distinctive dye that is injected into the bloodstream. A thin catheter is then inserted into the femoral artery of the leg, near the groin. The doctor monitors the path of the dye using x-rays. He moves the tube through the heart and into the plaque-filled artery. He inflates the balloon, creating more space, deflates the balloon, and removes the tube. It is important to note that the plaque has not been removed it has just been compressed against the sides of the artery. Sometimes, a stent may be implanted, a tiny tube of stainless steel that is expandable when necessary. Its function is to keep the artery open. 

Figure 2.10 The Loc-I-Gut instrument allowing segmental intestinal perfusion in humans. The balloons are filled with air when the proximal balloon has passed the ligament of Treitz. The six-channel tube facilitates infusion of drug and marker, aspiration of perfusate and gastric drainage, and inflation of the two balloons [60].

---