Reduce Experiments

we limit our summary to the most common optimization methods. An extended review of this topic has recently been given by Holena and Baems [13].  

Statistical methods have been used for a long time, especially in chemical industry, to reduce the number of experiments when a multiparameter problem has to be solved. Design of experiments (DoEs) or factorial design is the most frequently used method in high-throughput catalysis. Examples are NO oxidation over supported Pt influence of synthesis variables (Pt precursor, support, loading, calcination gas and temperature two levels each) [14] 

DoF methods are well suited when the number of parameters is low. However, if a multidimensional optimization (more than 10 parameters) 

For catalyst optimization using high-throughput experimentation, evolutionary strategies have been shown to be very effective if vast parameter spaces (many nominal catalyst components) have to be searched for the optimal catalyst composition. The concept of the algorithm has been described in detail by Wolf et al. [21], some application examples are discussed by Rodemerck et al. [22] and Holena [23]. 

The following features make these strategies valuable  

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Special attention shall be drawn to the preparation of the excised skin prior to the experiment. Long lag-times encountered with hydrophilic substances, as well as an unfavorable partition of lipophilic compounds into viable skin layers, may require the further separation of the skin into its individual layers [80], Furthermore, the absence of dermal blood flow in vitro may build up a significant hindrance to diffusion [81]. Reducing the membrane thickness will generally reduce experiment times and thus minimize the risk of bacterial contamination. 

The use of actively shielded magnetic field gradients has made the use of pulsed field gradients possible. The use of pulsed field gradients reduces experiment time, minimizes artifacts, and allows for further solvent suppression. 

Koskela, H.T., Plow to Improve Sensitivity and Reduce Experiment Time in 31P NMR Spectroscopy, VERIFTN, Helsinki, 2004. 

Selective pulses are widely used in many pulse sequences [5.88, 5.89], not just for solvent signal suppression. The transformation of an n dimensional experiment into a (n-x) dimensional experiment by the application of x selective pulses not only reduces experiment time but it also keeps the acquired data matrix to a minimum. The implementation of selective pulses can be easily incorporated into pulse sequence design but the choice of selective pulse and associated parameters depends upon the current problem under investigation. When implementing pulse sequences that use selective rf pulses the following aspects must be considered ... 

The high S/N available allows an increase in the quality of a spectmm for the same acquisition time or a substantially reduced experiment time for the same quality. In practice both these options are used - typically, fast correlation... 

At around the same time, a small circle of Nazi officials learned about the discovery of Soman, one of the most deadly nerve agents known to man, which stiU required further development. Unbeknown to Schrader and many others working in the chemical warfare field, Richard Kuhn, director of the Kaiser Wilhelm Institute for Medical Research in Heidelberg, and his team of scientists had been commissioned by the military to screen various organophosphorus compounds for their level of cholinesterase (ChE) inhibition, and had discovered Soman in the process. When inhaled. Soman turned out to be twice as toxic as Sarin, was able to penetrate through the skin, and quickly affected the central nervous system. Because it inhibited cholinesterase very rapidly, the effective use of antidotes such as atropine was considerably reduced. Experiments on dogs and apes at Gross laboratory in Elberfeld quickly established the enormous toxicity of the new substance. 

A few alternative COSY methods have been developed to improve the quality of spectra with large numbers of overlapping correlations or with large spectral windows. Selective COSY utilizes long-shaped pulses to excite a small window within the field of correlations in a spectrum. The smaller spectral window of the selective COSY experiment enhances digital resolution and reduces experiment time due to the reduced number of 2D increments required to obtain high digital resolution. The... 

An adequate prediction of multicomponent vapor-liquid equilibria requires an accurate description of the phase equilibria for the binary systems. We have reduced a large body of binary data including a variety of systems containing, for example, alcohols, ethers, ketones, organic acids, water, and hydrocarbons with the UNIQUAC equation. Experience has shown it to do as well as any of the other common models. V7hen all types of mixtures are considered, including partially miscible systems, the... 

To search for the forms of potentials we are considering here simple mechanical models. Two of them, namely cluster support algorithm (CSA) and plane support algorithm (PSA), were described in details in [6]. Providing the experiments with simulated and experimental data, it was shown that the iteration procedure yields the sweeping of the structures which are not volumetric-like or surface-like, correspondingly. While the number of required projections for the reconstruction is reduced by 10 -100 times, the quality of reconstruction estimated quantitatively remained quite comparative (sometimes even with less artefacts) with that result obtained by classic Computer Tomography (CT). 

During the past few years radioscopy has established itself in many fields that demand instant evaluation and a high degree of automation, as is the case in serial inspection. Furthermore, user experience has clearly shown that inspection costs can be considerably reduced by this technique. 

Practical experience has shown that, depending on the field of application, a considerable reduction in inspection costs can be had when opting for radioscopy rather than radiography. By comparison with film technique, the inspection time of turbine blades for aircraft jet propulsion engines is reduced by 45% to 60%. When adding film costs, approximately DM 450.000,- can be saved per year /3/. As far as... 

It can be observed from the Figure 1 that the sensitivity of I.I. system is quite low at lower thicknesses and improves as the thicknesses increase. Further the sensitivity is low in case of as observed images compared to processed images. This can be attributed to the quantum fluctuations in the number of photons received and also to the electronic and screen noise. Integration of the images reduces this noise by a factor of N where N is the number of frames. Another observation of interest from the experiment was that if the orientation of the wires was horizontal there was a decrease in the observed sensitivity. It can be observed from the contrast response curves that the response for defect detection is better in magnified modes compared to normal mode of the II tube. Further, it can be observed that the vertical resolution is better compared to horizontal which is in line with prediction by the sensitivity curves. 

The influence of sedimentation process on the value of reduced thickness of various dry powder developers is carried out in our experiments. Fig 1 illustrates the pictures of real developer s layers before (a, c) and after (b, d) penetrant application. The pictures were... 

The nominal inclination of the surface against the horizontal was 15°. Experiments indicate a relatively constant contrast, because Li and Ls decreasing proprtionally with increasing inclination. RI = -0.1 The magnetic particle content was reduced from 0.5 g/l to 0.25 g/1 This reduction seems realistic resulting in RP = -0.1... 

There are a number of observations to be drawn from the above fomuila the relative uncertainty can be reduced to an arbitrarily small value by increasing T, but because the relative uncertainty is proportional to /s/f, a reduction in relative uncertainty by a factor of two requires a factor of four increase in collection time. The relative uncertainty can also be reduced by reducing At. Flere, it is understood that At is the smallest time window that just includes all of the signal. At can be decreased by using the fastest possible detectors, preamplifiers and discriminators and minimizing time dispersion in the section of the experiment ahead of the detectors. 

Figure Bl.10.9. Plot of the reduced relative uncertainty of a double coincidence experiment as a fimction of the signal-to-background ratio. Note that the relative uncertainty decreases as the signal-to-background rate decreases.

In electron-spin-echo-detected EPR spectroscopy, spectral infomiation may, in principle, be obtained from a Fourier transfomiation of the second half of the echo shape, since it represents the FID of the refocused magnetizations, however, now recorded with much reduced deadtime problems. For the inhomogeneously broadened EPR lines considered here, however, the FID and therefore also the spin echo, show little structure. For this reason, the amplitude of tire echo is used as the main source of infomiation in ESE experiments. Recording the intensity of the two-pulse or tliree-pulse echo amplitude as a function of the external magnetic field defines electron-spm-echo- (ESE-)... 

Illuminating the sample at grazing angles. The penetration depth of photons depends on the cosine of the incidence angle and, therefore, can be reduced by this procedure. Although such an approach has limited use, it has been successfully employed in a few instances, such as for x-ray diffraction experiments. 

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