Turn-up Systems

The continuous process of paper production is interrupted at the reel, when the required roll diameter or web length has been reached. Now the paper web has to be cut, a fresh reel spool started and the finished parent roll discharged. So first the empty reel spool has to be accelerated to machine speed. With a standard Pope reel, the empty reel spool will now be lowered, till the nip is closed (Fig. 6.75). The reel is now ready for the turn-up which will be described separately. 

Some new generation reels show a different sequence. They first open the nip by moving the parent roll (Fig. 6.79). In order to avoid too much air being wound in an air squeezing element like a small roll or a brush on the parent roll is applied. 

Reel drum and parent roll are turning with Machine 

Entity reel spool and air squeezing rol have been atx elefaledtoVMa(hine 

Air squeezing roll has been applied and secondary nip opened 

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After the parent roll is in its end position, the primary arm can be lowered to the turn-up position and the primary nip is dosed. The turn-up position of the primary arm can now be varied between the position of a standard Pope reel and the position on the rails, depending on the demand of the turn-up system and the paper grade. The turn-up is easier and faster with self-threading concepts when the empty spool is already partly wrapped by the web. 

The air-supported tum-up systems have their main applications at basis weights up to 100 g nr, or in special cases up to 150 g m . A blowpipe formed like a gooseneck gave the name to one of these turn-up systems. A small cut of a few centimeters in the cross machine direction will be created, e.g. with a needle, in the middle of the web before the drum. The thus weakened web can be blown by the gooseneck blowpipe to the empty reel spool. The tear in the cross direction will be supported by two nozzles blowing from the middle to the edges between the primary and the secondary nip. 

Fig. 6.80 Turn-up system with high-pressure water jet and cutting form sheet (source Voith).

Thus, one must expect about 5-10% apparently significant correlations fortunately, these false positives appear in a random arrangement, so that when a really significant connection turns up, the human visual system perceives a clearly recognizable pattern, for example for file PROFILE.dat. (See Fig. 4.28.)... 

Lacking complete information on a given system, there are other avenues available for the preliminary investigation of the phase diagram. A thorough search of the literature may turn up individual phases in the system. While we have not yet reviewed X-ray crystallography, there are several crystallographic databases that provide valuable information. The first of these is the... 

In the case of the reduction of pentaminecobalt(III) complexes by Cr+2 which Prof. Taube has studied, some fast rates are now turning up. John Candlin has just completed measurement of the rates of reduction of the halopentamminecobalt(III) complexes by Cr+2 and determined that the rate constants lie in the range 106 to 107 Af- sec."1. This must be getting close to the substitution rates of the pent-amminecobalt halide into the coordination shell of the Cr+2. Although it would be helpful to have more information about substitutional rates of Cr42 to compare with these numbers, I think we are getting close to this limit in some of these systems. 

Certain combinations of masses turn up in mechanical arguments when discussing systems of more than one object. Such combinations are called the reduced mass for the system. One such combination is the reduced mass, ji, for the approach of two molecules to each other, given by... 

Considering that f, g, x, and u are vectors, the differentiation leads to formation of matrices. The matrix A is well known in stability analysis as the jacobian matrix it quantifies the effects of all state variables on their rates of change. A matrix similar to B turns up in metabolic control analysis, as N3v/3p [48, 108], where it denotes the immediate effects of parameter perturbations on the rates of change of all variables. If the function y is scalar and denotes a rate, then C becomes a row vector c harboring unsealed elasticity coefficients and D becomes a row vector d containing so-called n-elasticities - sensitivities of the rates with respect to the parameters [109]. The linearized system is ... 

In the words of Lancet and colleagues, a fundamentally different approach has envisaged primordial selfreplication as the collective property of ensembles of relatively simple molecules, interconnected by networks of mutually catalytic interactions. 38 The hereditary information in this case would be represented by the identity and concentration of its components. The term compositional genome has been used to describe this system, in which genetic information is not stored in a list, as in DNA, but is represented by the presence or absence of organic components.39,40 As an analogy, consider DNA to be the equivalent of a class list that records the full possible enrollment in a course. The information in a compositional genome would be represented by the presence of students who have turned up on a particular day. 

The trouble is, in this conformation none of the oxygen lone pairs get the chance to donate into the C-O a orbitals. Although putting the bonds anti-periplanar to one another makes steric sense, electronically, the molecule much prefers to put the lone pairs anti-periplanar to the C-O bonds, so the bonds themselves end up gauche (synclinal) to one another. This is known as the gauche effect, but is really just another way in which the stereoelectronic effects that give rise to the anomeric effect turn up in acyclic systems. 

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