Shots basics

Polyurethane foams may be rigid, semi-rigid or flexible. They may be made from polyesters, polyethers or natural polyols such as castor oil (which contains approximately three hydroxyl groups in each molecule). Three general processes are available known as one-shot, prepolymer or quasi-prepolymer processes. These variations lead to 27 basic types of product or process, all of which have been used commercially. This section deals only with flexible foams (which are made only from polyesters and polyethers). Since prepolymers and... 

The basic RIM process is illustrated in Fig. 4.47. A range of plastics lend themselves to the type of fast polymerisation reaction which is required in this process - polyesters, epoxies, nylons and vinyl monomers. However, by far the most commonly used material is polyurethane. The components A and B are an isocyanate and a polyol and these are kept circulating in their separate systems until an injection shot is required. At this point the two reactants are brought together in the mixing head and injected into the mould. 

T he radioactive products of a nuclear explosion are said to have under-gone fractionation if their relative proportions in samples taken at various locations differ significantly from their relative proportions as formed. This report describes a study of fractionation in the early fallout from the nuclear cratering shots Danny Boy, Sedan, and Palanquin. Published fallout data for these shots was the basic information used in the study. A normalization procedure was applied to the published data as follows the amount of each radionuclide (or mass chain) of interest measured on a fallout tray is related to the gamma-radiation exposure rate measured at the tray location and to the amount of that radionuclide produced per kiloton of fission by the device. The result is an index... 

If the system consists of a series of adiabatic reactors, there are two basic configurations. The first has heat exchangers or furnaces between each of the reactors to cool or heat the reactor effluent before it enters the next reactor. The second configuration uses cold shot cooling. Some of the cold reactor feed is bypassed around the upstream reac-tor(s) and mixed with the hot effluent from the reactor to lower the inlet temperature to the downstream catalyst bed. 

The basic experimental arrangement is shown in Figure 1. A Q-switched ruby pump laser is frequency doubled to pump a broadband dye laser with a piano-spherical cavity. The remaining ruby power and the dye pulse were then used for the non-linear spectroscopy experiments. Spectra were recorded on film or plates by means of a Spex Model 1701 spectrograph equipped with a camera. The smoothness of the dye output intensity with wavelength, which determines the sensitivity of the single-pulse spectra, varied from shot to shot and depended on the dye. 

For PI, basically all fast and strongly T2 w sequences can be used. In the early days of PI, measurements were performed using fast, T2 w gradient-echo sequences, particularly the fast low angle shot... 

There are basic differences in coke sizing and structure for delayed and fluid cokes because of differences in the two coking operations. Sometimes, fluidization occurs in delayed coke drums when the feed has a high asphaltene content and the recycle ratio is low. Such conditions tend to produce millimeter-size "shot" coke, which is very isotropic, and yields a calcined coke which is very hard with low porosity and high density. Such coke is hard to... 

MPX functionality is arranged into three modules, the first of which is the Setup Xpert, a module that allows users to perform a variety of injection-velocity- and pressure-phase-related setup routines to fix certain defects, such as short shots, flash, burn marks, sink marks, etc. The objective of Setup Xpert is to achieve one good molded part with no defects. The basic process is that a user molds a part, then provides feedback to the MPX system regarding molded part quality. The MPX system then processes this feedback along with data being collected from the machine and (if necessary) determines a process change that will improve the result. 

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