Synchronised production

Synchronised Production Transparency Value Analysis Vulnerabihty Analysis... 

The term stereoselective is often confused with the term stereospecific, and the literature abounds with views as to the most satisfactory definition. To offer some clarification, it is perhaps timely to recall a frequently used term, introduced a decade or so ago, namely the stereoelectronic requirements of a reaction. All concerted reactions (i.e. those taking place in a synchronised process of bond breaking and bond forming) are considered to have precise spatial requirements with regard to the orientation of the reactant and reagent. Common examples are SN2 displacement reactions (e.g. Section 5.10.4, p. 659), E2 anti) elimination reactions of alkyl halides (e.g. Section 5.2.1, p.488), syn (pyrolytic) elimination reactions (Section 5.2.1, p.489), trans and cis additions to alkenes (e.g. Section 5.4.5, p. 547), and many rearrangement reactions. In the case of chiral or geometric reactants, the stereoisomeric nature of the product is entirely dependent on the unique stereoelectronic requirement of the reaction such reactions are stereospecific. 

Progestogens, such as progesterone, and oestrogens have also been used in animal husbandry for herd or flock management to synchronise animals coming into season , so that breeding programmes can be planned, and to induce milk production. 

Although such a definition is seemingly quite clear and unique, the practical exploitation of the above criterion is complicated by the fact that the scission and formation of bonds is a microscopic process, inaccessible to direct experimental observation. This, of course, suggests the necessity of searching other, more easily exploitable, criteria of concert. One such criterion is the remarkable stereospecificity accompanying the formation of products in allowed pericyclic reactions [60,61]. The fact that the origin of the synchronisation in the process of scission and the formation of the bonds was always intuitively related to a certain energetic stabilisation led to another widespread opinion that all allowed reactions are automatically concerted. On the other hand nonconcertedness, advocated by frequently observed stereo-randomization [60] was practically always expected in forbidden reactions. 

The majority of thermoforming production is by roll fed machines. Sheet fed machines are used for the smaller volume applications. Larger production units have in house sheet extrusion equipment. Because of the complexities in synchronising sheet extrusion equipment and the thermoforming machines, the two processes can be carried out independently of each other, the extruded sheet being produced in advance of production schedules. 

It has been shown [34,35] that the prevention of intercellular communication can lead to synchronisation of whole cultures, thus facilitating the production of cell-cycle specific metabolites of pharmaceutical importance. Perhaps a similar approach could be used in pharmacological analysis of drugs and their effects on individual cells rather than on whole tissue. 

Switching the injection device (two synchronised single injection valves or a double injection valve) inserts the sample and reagent aliquots into their convergent carrier streams and the established sample and reagent zones are pushed towards the stream convergence site. The chemical reactions involved proceed inside the reactor and the formed product is monitored by the flow-through detector. 

Acceleration to a constant velocity the time taken for objects to travel from the optical inspection point to the ejection point must be constant so that activation of the ejector can be accurately synchronised with the position of the object. Typically, the velocity of the product is of the order of 4 m/s. The delay between detection and ejection is between 0.5 and 100 ms. 

As with tumour spheroid production, multiarray chips were also used to produce hESC aggregates. An anisotropic ally etched mould in silicon was used as a template for pyramid-shaped PDMS wells for high-throughput production of aggregates (Fig. 17) [135]. These chips were used to generate spatially and temporally synchronised hESC aggregates, which can be used for further fundamental studies in early human development processes. Another method used PEG-coated wells... 

In Section 9.5.2, a rotor-synchronised H- H DQ MAS spectrum was presented (Fig. 9.20). The 2D DQ MAS can be performed in an alternative fashion if the ti increment is reduced, which corresponds to an increase in the DQ spectral width, a DQ MAS spinning-sideband pattern is observed [120, 121]. Such DQ MAS sideband patterns exhibit characteristic unusual features. In particular, the observed patterns are very sensitive to the product of the dipolar coupling constant,... 

PDI extraction requires synchronisation of the oxidative process in neighbouring methylene chains, separated by a polymellitimide fragment. Random chain initiation and transmission would cause the occurrence of a series of oligomers in products of solid-phase oxidation. 

Single-screw extruders are commonly used for the conversion of polymers into prodncts such as pipe, cables, film and so on. It is used for compounding with a modification of the screw, feed zone and mixing zone. The compounding operation can be synchronised with product extrusion in a single operation. 

Adhesives may also be applied as dots at very high speeds, thousands of dots per minute. The application is controlled by microprocessors a numeric coder integrated to the production line synchronises the adhesive application and the line speed, with a precision of 1 mm. The flow of adhesive is also controlled by this microprocessor. 

Flash techniques were originally developed for the study of gas reactions [2,g] but were soon applied to solutions [2,h]. By the mid-60s, apparatus with a time-resolution of a few microseconds, using gas flash-lamps, had come into common use. With such equipment it was possible to identify transient species in solution from their spectra, and to determine their rates of decay and other processes. Excited states became recognised as distinct chemical species. The first study in which the spectra of the initial excited state, of the products and of some radical intermediates, were all detected in solution, and the kinetics investigated, was published in 1958 [2,k], Nanosecond pulses became available after the invention of the laser in 1960, but were not applied in flash photolysis until the problem of synchronising the analysing ( probe ) flash with the initiating ( pump ) flash was solved... 

In laser vaporisation experiments, generating a plume , the laser s frequency may be synchronised with the resonance line of the element (analyte) to be analysed. The basic principles are (i) absorption of the radiation by the analyte (LAAS laser atomic absorption spectrometry) (ii) fluorescence (LIE, laser-induced fluorescence LEAFS) or (Hi) production of ionisation products (ions and electrons). LIF is an analytical method of high precision that is suitable for the measurement of diatomic species in the plume. Excitation spectroscopy or laser-excited fluorescence is not concerned with the spectral composition of the fluorescence but with how the overall intensity of emission varies with the wavelength of excitation. 

The synthesis over time is more difficult to explain, but no less essential. In many kinds of activities - probably in all -synchronisation is important. This certainly goes for industries where safety (whether as Safety-I or as Safety-II) is a concern it goes for services for communication for production - not least if it is lean and so on. Synchronisation is achieved by organising the various productive processes to avoid delays (outputs arriving too early or too late), to ensure a better use of the resources (for instance, doing things in parallel so that the same preconditions do not have to be established twice), to coordinate transportation... 

Dell s ability to operate a build-to-order strategy is based partly on the modular design of many of their products but more particularly on a very high level of synchronisation with their suppliers. There is a high level of visibility across the Dell supply chain with suppliers receiving information on Dell s order book every two hours. Ahead of fhis informafion, suppliers are provided with capacity forecasts from Dell fo enable fhem fo produce af a rafe fhat is planned to match actual demand. 

Transparency of information upstream and downstream is essential for synchronisation to work. For example, the supplier must be able to access the customer s forward production schedules, and the customer must be able to see into the supplier s stockroom. The virtual supply chain envisages partners in the chain being linked together by a common information system, so that information replaces the need for inventories. 

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