Longitudinal direction

A variation of the preceding process is used to produce oriented vinyUdene chloride copolymer films. The plastic is extmded into tube form and then is supercooled and subsequently biaxiaHy oriented in a continuous bubble process. The supercooled tube is flattened and passed through two sets of pinch roUs, which are arranged so that the second set of roUs travels faster than the first set. Between the two sets, air is injected into the tube to create a bubble that is entrapped by the pinch roUs. The entrapped air bubble remains stationary while the extmded tube is oriented as it passes around the bubble. Orientation is produced in the transverse and the longitudinal directions, creating excellent tensile strength, elongation, and flexibiUty in the film. The commercial procedure has been described (157). 

The dummy tubes do not pass through the tubesheets, and can be located close to the inside of the shell. The seating strips extend from baffle to baffle in a longitudinal direction and effectively channel the fluid across the tubes to minimize turbulence and heat transfer. On some fixed tubesheet designs, the outer tubes are in close proximity to the inside of the shell so that by-pass is minimal and no by-pass elimination is necessary. There are a number of... 

Influent water enters one end of the pressure vessel and travels longitudinally down the length of the vessel in the feed transport layer. Direct entry into the permeate transport layer is precluded by sealing this layer at each end of the roll. As the water travels in a longitudinal direction, some of it passes in radially through the membrane into the permeate transport layer. Once in the transport layer, the purified water flows spirally into the center collection tube and exits the vessel at each end. The concentrated feed continues along the feed transport material and exits the vessel on the opposite end from which it entered. 

The properties of a unidirectional fibre will not be nearly so good in the transverse direction compared with the longitudinal direction. As a material in service is likely to be subjected to stresses and strains in all directions it is important to be aware of the properties in all directions. The transverse direction will, of course, be the weakest direction and so it is necessary to pay particular attention to this. 

Groundwater pollution problems, however, are modeled using a two dimensional analysis. A typical aquifer has area dimensions that are much hirger than the vertical dimension. Therefore, chemictils dissolved in the groundwater aclticvc ertical uniformity a short distance from the source and the chemical plume will move in the lateral and longitudinal directions. 

NOTE 2 Tensile specimens from drill collars shall be taken vithin S feet of the end of the drill collar in a longitudinal direction, having the centerline of the tensile specimen 1 inch from the outMe surface or midwall, whichever is less. 

Given these differences between rigid and flexible conduit, let us examine the differences between steel and RTR pipe, both of which are, of course, flexible conduits. First, steel pipe is by definition constructed from a material, steel, that for our purposes is a homogeneous isotropic substance. Therefore, steel pipe can be considered to have the same material properties in all directions that is, it is equally strong in both the hoop and longitudinal directions [Fig. 4-2(b)]. 

Therefore, before a final wall structure can be selected, it is necessary to conduct a combined strain analysis in both the longitudinal and hoop directions. This analysis will consider thermal contraction strains, the internal pressure, and the pipe s ability to bridge soft spots in the trench s bedding. In order to do this we must know more about the inherent properties of the material we are dealing with that is a structure made up of successive layers of continuous filament-wound fiberglass strands embedded within a plastic matrix. We must know the modulus of the material in the longitudinal direction and the... 

In this Fig. 8-41 view (a) the feeder-roll speed to puller-roll speed ratio can be set, such as 1 4, and simultaneously the ratio of width can be set as 1 4. The machined direction ratio is usually accomplished prior to the plastic s entering the temperature controlled oven that contains the tenter frame, by having it move around heat-controlled rolls where the rotational speed of the rolls increases from one roll to the next. View (b) is a schematic of the drawdown phenomenon with swell to produce orientation in the machined (longitudinal) direction. 

Isotropic transverse construction Refers to a material that exhibits a special case of or-thotropy in which properties are identical in two orthotropic dimensions but not the third. Having identical properties in both transverse but not in the longitudinal direction. 

Corrugated sections Yes Yes Circumferential only In longitudinal direction Yes Yes... 

According to Hosemann-Bonart s model8), an oriented polymeric material consists of plate-like more or less curved folded lamellae extended mostly in the direction normal to that of the sample orientation so that the chain orientation in these crystalline formations coincides with the stretching direction. These lamellae are connected with each other by some amount of tie chains, but most chains emerge from the crystal bend and return to the same crystal-forming folds. If this model adequately describes the structure of oriented systems, the mechanical properties in the longitudinal direction are expected to be mainly determined by the number and properties of tie chains in the amorphous regions that are the weak spots of the oriented system (as compared to the crystallite)9). 

Figure 15.2 Polarized absorption spectra of SWNT/MEHPPV composites on glass plates in (a) the absence (OT) and (b) the presence of magnetic processing (8T). In the absence of magnetic processing (OT), the polarization direction of the light against the longitudinal direction of the glass plates is horizontal...

Geogrids are very strong in transverse and longitudinal directions, making them useful as reinforcing materials for either soil or solid waste. Generally, they are used to steepen the side slopes of... 

---