Factorial design application

Curved one-factor response surface showing (a) the limitation of a 2 factorial design for modeling second-order effects and (b) the application of a 3 factorial design for modeling second-order effects. 

Mathews and Rawlings (1998) successfully applied model-based control using solids hold-up and liquid density measurements to control the filtrability of a photochemical product. Togkalidou etal. (2001) report results of a factorial design approach to investigate relative effects of operating conditions on the filtration resistance of slurry produced in a semi-continuous batch crystallizer using various empirical chemometric methods. This method is proposed as an alternative approach to the development of first principle mathematical models of crystallization for application to non-ideal crystals shapes such as needles found in many pharmaceutical crystals. 

Sodium chlorite reacts very violently with organic compounds of divalent sulfur, or with free sulfur (which may ignite), even in presence of water. Contact of the chlorite with rubber vulcanised with sulfur or a divalent sulfur compound should therefore be avoided [1]. Application of factorial design techniques to experimental planning gave specific conditions for the safe oxidation of organic sulfides to sulfoxides using sodium chlorite or calcium hypochlorite [2],... 

Techniques, such as the application of factorial designs, are normally only applicable where various compounding changes are being evaluated or if several levels of more than one environmental agent are included in the experiment. 

Application of 2 fractional factorial design allowed the optimization of the gradient HPLC proeednie for the determination of ibnprofen, pseudoephedrine HCl, ehlor-pheniramine maleate and nipagen in symp preparation. The optimum eonditions for this determination were found to be 3 of pH, 1.5 mL/min of flow rate, 85%, 55% and 40% of buffer eompositions of steps of gradient profde. 

In some applications, Latin square designs can be thought of as fractional three-level factorial designs that allow the estimation of one main factor effect while... 

Box et al. [20] provide a good introduction to factorial designs, the most thorough ruggedness test would involve the application of a full factorial design that tests all main effects and interaction effects. 

The first case study we will consider is the assay of aspirin together with its major degradation product salicylic acid [19], This application study was selected as the HPLC assay of aspirin is well covered in the literature and we could select factors to test from the variety of HPLC conditions used in these published methods. This test was performed using a reflected saturated factorial design requiring a total of 15 experiments. 

J.O. Waltersson, Factorial designs in pharmaceutical preformulation studies. I. Evaluation of the application of factorial designs to a stability study of dmgs in suspension form. Act. Pharm. Suec., 23 (1986) 129. 

Statistical optimization of a controlled release formulation obtained by a double-compression process Application of a Hadamard matrix and a factorial design... 

E. Kenduezler, O. Yalcinkaya, S. Baytak and A. R. Tuerker, Application of full factorial design for the preconcentration of chromium by solid phase extraction with Amberlyst 36 resin, Microchim. Acta, 160(4), 2008, 389-395. 

N. Jalbani, T. G. Kazi, B. M. Arain, M. K. Jamali, H. I. Afridi and R. A. Sarfraz, Application of factorial design in optimisation of ultrasonic -assisted extraction of aluminum in juices and soft drinks, Talanta, 70(2), 2006, 307-314. 

B. Izgi, C. Demir and S. Gucer, Application of factorial design for mercury determination by trapping and graphite furnace atomic absorption spectrometry, Spectrochim. Acta, Part B, 55(7), 2000, 971-977. 

M. Villanueva, M. Pomares, M. Catases and J. Diaz, Application of factorial designs for the description and correction of combined matrix effects in ICP-AES, Quim. Anal., 19(1), 2000, 39-42. 

M. Zougagh, P. C. Rudner, A. Garcia-de-Torres and J. M. Cano-Pavon, Application of Doehlert matrix and factorial designs in the optimisation of experimental variables associated with the on-line preconcentration and determination of zinc by flow injection inductively coupled plasma atomic emission spectrometry, J. Anal. At. Spectrom., 15(12), 2000, 1589-1594. 

B. Hilligsoe and E. H. Hansen, Application of factorial designs and simplex optimisation in the development of flow injection-hydride generation-graphite furnace atomic absorption spectrometry (FI-HG-GFAAS) procedures as demonstrated for the determination of trace levels of germanium, Fresenius J. Anal. Chem., 358(7-8), 1997, 775-780. 

Although factorial designs are very useful for studying multiple variables at various levels, typically they will not be applicable to cosolvent solubility studies because of the constraint that all of the components must add to 100%. Forthis reason, mixtures of experimental designs are typically used. The statistical theory behind mixture designs has been extensively published [81-85], There... 

Sahoo, N.R. and Pandalai, H.S. (2000) Secondary geochemical dispersion in the Precambrian auriferous Hutti-Maski schist belt, Raichur district, Karnataka, India. Part II. Application of factorial design in the analysis of secondary dispersion of As. Journal of Geochemical Exploration, 71(3), 291-303. 

Figure 6.19. Sequential application of complete factorial designs in the same situation as in Figure 6.18a. An alternative approach is the method of steepest ascent indicated by the dotted line.

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