Process cycle for

Table 1. Processing Cycle for Engineering Nickel on Low Carbon Steel ...

FIO. 19-53 Basic process cycle for a reciprocating canister superconducting magnetic separator. (Couttesy Carpco, Inc.)... 

The term off-kilogram (off-pound) shall mean the mass of aluminum or aluminum alloy removed from a forming or ancillary operation at the end of a process cycle for transfer to a different machine or process. 

The standard process cycle for polymer matrix composites is a two-step cure cycle, as seen in Figure 8.1. In such cycles the temperature of the material is increased from room temperature to the first dwell temperature and this temperature is held constant for the first dwell period ( 1 hour). Afterward, the temperature is increased again to the second dwell temperature and held constant for the second dwell period (2-8 hours). After the second dwell, the part is cooled down to room temperature at a constant rate. Because there are two dwell periods, this type of cure cycle is referred to as a two-step cure cycle. The purpose of the first dwell is to allow gases (e.g., entrapped air, water vapor, or volatiles) to escape and to allow the matrix to flow, which leads to compaction of the part. Thus, the viscosity of the matrix must be low during the first dwell. Typical viscosity versus temperature profiles of polymer matrices show that as the temperature is increased, the viscosity of the polymer decreases until a minimum viscosity is reached. As the temperature is increased further, the polymer begins to cure rapidly and the viscosity increases dramatically. The first dwell temperature must be chosen judiciously so that the viscosity of the resin is low while the cure is kept to a minimum. 

There are a number of tools available to the process engineer for designing a preset process cycle for regulating secondary variables such as temperature and pressure and for supervisory control of the process cycle based on inferred composite properties. Many of these have been tested in a variety of applications. None of these tools is capable of handling all of the tasks of a batch process controller but they can be combined, and the resulting systems have potential far beyond that of any one tool by itself. 

On the other hand, once one has melt flowing into the mold, one would like the fastest possible reaction to produce final cure and a short process cycle for maximum process economy. This clearly means high reactivity. 

Filling of NS compartments with consistent immobilizing mixture could be performed via standard hatches and openings. The process cycle for monolithization of inner volumes of compartments and inter-board areas is illustrated in Figure 1. 

Figure 5.10 Comparison of processing cycles for conventional and integrated processing of a two-component jrart [29],...

Figure 13.1. Organic compound process cycle for synthesis, storage, and screening of new chemical entities in early drug discovery programs.

We must know the process cycle time for a batch or semi-batch process in order to estimate the number of reactors required for a given plant capacity and to estimate the staffing requirement for that plant. By process cycle time, we mean the time between initiating one reaction and the next, subsequent reaction. One process cycle for a batch or semi-batch process involves... 

Figure 2.19 Evolution of temperature at the outlets of the three beds for a long run (a) and zoomed in for one process cycle for one bed (b)...

Very little work has been presented in the literature on the monitoring of tooling forces during RTM or LCM processes. While a load cell can easily be mounted on the hydraulic ram of a press, the local forces and ratio of reinforcement stress and fluid pressure are often ignored. By using a distributed pressure sensor placed inside the mould, Walbran and co-workers [72, 89, 99] were able to measure spatial variation in the normal stresses applied to the mould during the process cycles for RTM and CRTM, and to isolate the fluid forces from forces due to preform compaction. 

Co-cure - a manutecturing technique for producing adhesive bonds between composite adherends at the same time as consolidating and curing the composite, i.e. same process cycle for composite and adhesive. 

Figure 13.16 Typical time-versus-temperature processing cycle for a Li20-Al203-Si02 glass-ceramic.

Fission-product poisons in the core. The level of fission products, FP, other than xenon and samarium, in the core is determined by the chemical processing cycle for the core fuel solution. The steady-state value of FP poisons in the core should be established by an economic balance between the value of improved breeding ratio and increased chemical processing costs. The relationship between the core processing cycle, Tc, and the rela-ti e poison, IIP, in the core may be expressed as... 

Fi.%nou-pni(hict poisons. The adjustment of breeding ratio to correspond to the effects outlined above chtinges the required chemical processing cycle for thi lilanket system. This change in Tb also changes the equilibrium... 

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