thermal cracking of a heavy liquid hydrocarbon was performed in a laboratory scale tubular reactor. central composite design (ccd), was used as an experimental design method. the design variables were coil outlet temperature (cot), feed flow and rate steam ratio. maximum yield of ethylene was 30.37 wt% at cot, residence time and steam ratio of 869oc, 0.208 s and 1.22 g/g, respectively. maximum ...

in this article a comparative study for modeling and optimization of 2-methylpropane-2-thiol removal from contaminated soil by ultrasound is investigated. central composite design (ccd) and artificial neural network (ann) were utilized and compared to each other in order to obtain appropriate predicting model with respect to sonication power (w), sonication time (min) and water/reactor volume r...

the aim of this work was to develop a new and simple coacervative extraction method for the preconcentration and spectrophotometric determination of cu(ii) in water samples. dithizone was used as the chelating agent while an anionic surfactant, namely sodium dodecyl sulfate (sds), was used as extracting agent at room temperature. central composite design (ccd) based on response surface methodol...

ultrasound-assisted extraction was used to determine the optimum processing conditions and to achieve the maximum extraction yield and viscosity of the gum extracted from quince seed. using response surface methodology (rsm) to design the experiments and adopting the central composite rotatable design (ccrd), the effect of extraction temperature (25-55°c), time (3-10 minutes), and ph (6-8) were...

the current study is an attempt to contribute for efficient and cost-effective substrates for xanthan gum production. in this context, the sugar cane molasses wastes can be used as a cheap substrate for xanthan gum production. xanthan biopolymer production by a novel xanthomonas campestris strain ibrc-m 10644 was optimized with statistical approaches. based on the results of response surface me...

Central composite design (CCD) is widely applied in many fields to construct a second-order response surface model with quantitative factors help increase the precision of estimated model. When an experiment also includes qualitative factors, effects between and should be taken into consideration. In present paper, D-optimal designs are investigated for models where interact with, respectively,...

Poly(vinylidene fluoride) (PVDF) nanofibers were prepared via electrospinning process. Several different factors influence on this process and application of experimental design for its optimization is of great importance. The central composite design (CCD) was used for planning and optimizing of the experiments and also, the analysis of variance (ANOVA) was employed for the statistical va...

The present study investigates the relationships and parameter interactions between three controllable variables (lamp current, pulse frequency and air pressure) on hole taper in micro-drilling operations, in order to assess the effect of the different process parameters and also material properties in laser micro-drilling operations. Micro-drilling experiments have been conducted for Gamma-Tit...