Speed optimization

Microwave heating can readily be adapted to a parallel or automatic sequential processing format. In particular, the latter technique allows for the rapid testing of new ideas and high-speed optimization of reaction conditions. The fact that a... 

If the LC part is optimized to deliver peaks in a shorter time or more peaks in the same time when compared to a conventional method, we must consider the system s ability to handle data. Because the speed optimization described above will produce much narrower peaks, widths below 1 sec can be achieved easily. However, the data acquisition rate and data filtering steps must be considered. 

To identify a compound, five data points per peak may be sufficient. Quantitation may require at least 10 data points across a peak. Many of today s laboratories still house standard detectors (UV, ELSD, fluorescence, etc.) with maximum data acquisition rates at or below 20 Hz. Many conventional LC/MS methods acquire data at rates of 5 Hz or less. As shown in Figure 3.8, this is not sufficient for modem speed optimized chromatography. Obviously, selecting the wrong data acquisition rate will nullify all attempts to optimize chromatography. 

Noteberg, D., Schaal, W., Hamelink, E., Vrang, L. and Larhed, M., High-speed optimization of inhibitors of the malarial proteases Plasmepsin I and Ii., J. Comb. Chem., 2003, 5, 456-464. 

Rotation speed too slow Rotation speed optimal Rotation speed too fast 8-U r/min. 6-10° drum angle... 

Rutner, Stephen, Waller, Matthew A., and Mentzer, John T., A practical look at RFID, Supply Chain Management Review, January/February 2004. Schragenhiem, Eli and Dettmer, H. William, Manufacturing at Warp Speed Optimizing Supply Chain Financial Performance, Boca Raton, FL APICS/St. Lucie Press, 2001. 

At this point, the stationary phase particle diameter is extremely important for the kinetic optimization of separations. A smaller particle diameter reduces the distance for the necessary radial diffusion of analyte molecules on the one hand, but increases the geometrical radial concentration gradient that drives the diffusion. Both effects are synergistic for an efficient analyte transport and this is the physicochemical foundation for the decrease of the C-term with the squared particle diameter (dp ). This will be used effectively in the speed optimization strategy. 

As well as the two rules discussed for the speed optimization of isocratic methods, it is necessary to include another rule to allow for the correct optimization of gradient programs. In order to make sure that the shorter and more efficient column is not overloaded by volume and to achieve the same peak height in a concentration proportional detector, it is necessary to include another rule in both isocratic and gradient speed-up. If the column diameter is not changed during the method change, these additional rules are as follows ... 

We have seen with the speed-optimization in Section 2.3.4 that the particle size dp is the predominant parameter to influence the plate number, N, being the primary descriptor for efficiency to enable kinetic improvement of HPLC methods. Temperature can also change kinetic parameters in HPLC, but to a smaller extent than particle size and it simultaneously changes thermodynamic parameters such as retention and can sometimes even alter the selectivity. Kinetic optimization is mostly about increasing speed of analysis by providing a method that generates the same A in a shorter time. We now see how an increase of N through column parameters can improve resolution and what considerations have to be made. 

Even with speed optimized UHPLC methods in the second dimension, such methods take at least 4 h to run, which corresponds to a peak production rate of 10—15 peaks/min. Highly speed optimized 2D-LC methods for moderate peak capacities of up to 1800 can nowadays be run in approximately 100 min, which corresponds to peak production rates of up to 18 peaks/min. 

Cramers, C.A. Leclercq, P.A. Strategies for speed optimization in gas chromatography An overview. J. Chromatogr. 

Abrasion is usually a major consideration in pump selection. Except for the mild chemical-type duties already referred to, slurry pumps are of special construction, essentially to resist abrasion to the pump and its shaft seals but often also to permit fast maintenance and liner or component replacement for very abrasive duties. Generally either replaceable rubber lining or specially hard abrasion-resistant alloys are used shaft seals are of special design, and are usually continually flushed with clean water. Impeller tip velocities are kept within proven limits for the application. Power transmission is often through V-belts rather than direct-drive couplings, to permit exactly the required speed to be obtained (rather than synchronous speeds) and to permit speed optimization in service (varying the impeller diameter is not so convenient). 

The mixing of the reaction phases is also important for the reaction rate so as to provide maximum liquid-liquid interfacial area in cases where the reaction occurs mostly at the liquid-liquid interface and not in the bulk aqueous phase. This can be achieved by high agitation speeds, optimized stirrer type and geometry. In aqueous two-phase systems also the hold-up of the aqueous phase plays an important role on the reaction rate. With too high hold-up volumes the reaction rate starts to decrease (phase inversion yielding... 

The most dramatic contributor to changes in design tools in the last 25 years has been computer technology. With today s computational speeds, optimization and simplification of new plant design and construction seems to be limited only by the imagination. One has only to compare modem development tools to historical methods to appreciate the change. 

Some measure of speed optimization is usually achieved through area optimization, as the area optimization removes redundant circuitry and can shorten the critical path of the circuit. However, further speed optimization can also be performed. 

Speed optimization is usually applied after area optimization has taken place. Speed optimization will improve the performance but only to a certain extent. If after speed optimization the circuit still does not meet the design specification, then the designer must go back and restructure the VHDL. Often this approach involves replacing a behavioural specification with a dataflow or structural one. A good example would be replacing a behavioural description of an add operation by a structural equivalent that implemented a fast carry-propagate mechanism. 

Not all the architectural descriptions presented in this section are synthesized and/or optimized. One particular circuit contains no new constructs but is a use l example for demonstrating the process of speed optimization. 

A performance (speed) optimization stage in which predefined timing figures had to be achieved. For each adder circuit, the critical path (input to output) had to be less than 5ns. T o compare the structures of circuits with this performance, the area was unconstrained. Alow level of performance optimization effort was always applied first. If the constraint could not be met, medium and then high levels were tried. Only in one case did a circuit fail to meet its target. The level of effort required for each circuit has not been recorded. 

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