Intermittent processes

The sequencing batch reactor (SBR) or intermittent process is a combination of complete mix and plug dow, and usually controls filamentous bulking. The nature of the process eliminates the need for an external clarifier. 

In the intermittent processes, single or multiple parisons are extruded using a reciprocating screw or ram accumulator. In the former system the screw moves forward to extrude the parisons and then screws back to prepare the charge of molten plastic for the next shot. In the other system the screw extruder supplies a constant output to an accumulator. A ram then pushes melt from the accumulator to produce a parison as required. 

Most reported cases of severe illness from nitrogen dioxide have been accidental exposures to explosion or combustion of nitroex-plosives, or from the intermittent process of arc or gas welding (especially in a confined space). 

Classy. Self-Assembly with Intermittent Processing... 

Self-assembly can be divided into a number of classes 1. strict self-assembly, 2. irreversible self-assembly, 3. precursor modification followed by self-assembly, 4. self-assembly with post-modification, 5. assisted self-assembly, 6. directed self-assembly, 7. self-assembly with intermittent processing. 

We have now to illustrate the dynamic model used to derive v /(t). It rests on the physics of intermittent processes, namely, on a model adopted to account for turbulence [39]. This is a popular prototype of deterministic approach to turbulence given by the Manneville map [40], This map reads... 

Contrary to most other ionization sources that yield a continuous ion beam, MALDI is a pulsed ionization technique that produces ions in bundles by an intermittent process. The pulsed nature of the MALDI source is well suited for the time-of-flight (TOF) analyser. In addition, the TOF analyser has the ability to analyse ions over a wide mass range and thus... 

In certain applications, the exhaust stream may contain sulfuric acid and other acids that can be highly corrosive. At operating temperatures above 450°F, these corrosives are in the gas phase and not a problem. However, in intermittent processes, with frequent shutdowns and startups, these acids fall below their dewpoint and corrosive condensation eats away the steel baghouse walls. 

Self-assembly processes involving covalent modifications typically comprise one of the earlier classes of self-assembly followed by, preceded by, or intermixed with conventional covalent bond formation. In coordination chemistry, for example, self-assembly with precursor modification means synthesizing the component ligands and metal complexes before carrying out the reaction. Post-modification involves locking a self-assembled structure into a kinetically stable state. Self-assembly with intermittent processing involves combinations of both of these. 

With die cutting this may be done by platen (intermittent process) whereby the web is stopped, or rotary (continuous motion). The latter process is considerably more expensive. 

The penetration theory was proposed by Higbie19 who observed that the mass transfer of a solute A from a liquid to a gas in industrial processes could be regarded as a succession of intermittent processes wherein each bubble of vapor is exposed to a succession of liquid surfaces. Each liquid surface is visualized as forming at the top of the bubble and remaining in contact with it for amount of time t, equal to that required for the bubble to move through a distance equal to one bubble diameter. The mass transfer process over the time period t was described by the partial differential equation known as Fick s second law. The solution obtained for a suitable set of boundary conditions led to the following expression for NA, the rate of transfer of A from the liquid to the vapor per unit of interfacial area... 

Poly(vinyl chloride), unlike polyethylene, is a heat-sensitive polymer. If used in the intermittent process, it may suffer some degradation because polymer melt has to be kept hot in the extruder during the blowing, cooling, and removal of part from the mold. 

Furthermore, as a consequence of the fact that the polymerization active species is the product of reversible equilibria reactions, the propagating process of a growing species is an intermittent process (Fig 7, right), which results in a particular development of the molar mass distribution of the polymers formed. This molar mass distribution is now an important additional tool for the elucidation of complex polymerization mechanisms. It is well known that the molar mass distribution contains and reflects the complete kinetic history. We will refer to this important relation in Sect. 2.3. 

Many well-known continuous drying processes were naturally intermittent processes. Indeed, sun drying (grains, fruits, herbs, etc.) can be studied as natural intermittent drying processes with almost 24 h drying/tempering cycles. Intermittent... 

Steady state n. A condition of processes or parts of processes in which the state variables describing the process, e.g., temperature, pressure, compositions and velocities of streams, and amounts of materials residing in various process equipment, do not change with time. Most extrusion operations closely approximate the steady state except during startup and shutdown, whereas injection molding and sheet thermoforming are unsteady, intermittent processes. 

Exposures to substances with exceptionaily high PELs (Permi.ssible Exposure Limits) in relatively dust-free atmospheres, e.g., ferric oxide and aluminum oxide. Intermittent processes with substances without STELs (Short Term Exposure Limits),... 

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