Screen design

A metal screen designed to remove particles and sediments that would be detrimental to steam traps and other devices. 

Vander Heyden, Y., Khots, M. S., and Massart, D. L., Three-Level Screening Designs for the Optimization or the Ruggedness Testing of Analytical Procedures, Analytica Chimica Acta 276, 1993, 189-195. 

Table 2. Fractional-factorial screening design for RF foams...

Screening designs are mainly used in the intial exploratory phase to identify the most important variables governing the system performance. Once all the important parameters have been identified and it is anticipated that the linear model in Eqn (2) is inadequate to model the experimental data, then second-order polynomials are commonly used to extend the linear model. These models take the form of Eqn (3), where (3j are the coefficients for the squared terms in the model and 3-way and higher-order interactions are excluded. 

A complete list of the reaction conditions tested for this response surface design can be found in [76], The center point reaction condition was repeated six times. This was done to measure the variability of the reaction system. Also, the space velocity is kept constant, as it was the least important factor predicted by screening design, for all the reaction conditions. The purpose of this nested response surface design was to develop an empirical model in the form of Eqn (5) to relate the five reaction condition variables and the three catalyst composition variables to the observed catalytic performance. 

Examples of successful natural product screens directed against proven targets include screens designed to look for inhibitors of bacterial cell wall biosynthesis. These screens were established once it became clear... 

Proper dose selection is essential for effective and efficient screen design and conduct. If insufficient data are available, a suitably broad range of doses must be evaluated (however, this technique is undesirable on multiple grounds, as has already been pointed out). 

The terminology involved in screen design and evaluation and the characteristics of a screen should be clearly stated and understood. The characteristics of screen performance are defined as... 

Both discovery and discrimination in screens hinge on the decision criterion that is used to determine if activity has or has not been detected. How sharply such a criterion is defined and how well it reflects the working of a screening system are two of the critical factors driving screen design. 

There are three major types of screen designs the single stage, sequential, and tiered. Both the sequential and tiered are multistage approaches, and each of these types also varies in terms of how many parameters are measured. But these three major types can be considered as having the following characteristics. 

Andersson M. Ringberg A. Gustafsson C. Multivariate methods in tablet formulation suitable for early drug development Predictive models from a screening design of several linked responses. Chemometrics and Intelligent Laboratory Systems, 2007, 87 (1), 151-156. 

Optoelectronics covering of displays, from small LCDs in cellular phones to large rear-projection television sets or screens designed for audio-visual presentations... Transparent technical parts indicators, dials, inspection holes, caps, casings, hoods and other electrical parts... 

In this chapter, the possibilities to set up and treat the results of a robustness test were reviewed (Sections I-VIII). Robusmess usually is verified using two-level screening designs, such as FF and PB designs. These designs allow examining the effects of several mixmre-related, quantitative, and qualitative factors, on one or several responses, describing either quantitative and/or qualitative aspects of the analytical method. 

There is a class of experimental designs, called screening designs, that can be used to sieve factors. Behind almost all of these designs is an implicit linear model that is first-order in each factor. The model is... 

Note that for k factors, the model will have k + 1 parameters - one for each of the factors being investigated plus one for the offset term (Pq). After this model has been fitted to the data obtained from a screening design, the P s can be used to determine whether the factor is small and can be discarded, or is large and should be retained. 

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