response surface modelling
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Abstract This study focusses on the photocatalytic degradation of caffeine (CAF) a stimulating drug and environmental contaminant that pose threat to humans and the environment. The effect of operating parameters such as; CAF initial concentration (5–20 mg/L), catalyst dosage (0.1–0.9 g/L) and pH (3.0–9.0) were explored in detail. The experimental results showed the maximum CAF and chemical oxygen demand (COD) removals of 87.2% and 66.7% respectively. The optimized parameters were; CAF initial concentration – 5 mg/L, catalyst dosage – 0.5 g/L and pH – 7.2. The photocatalytic degradation of CAF followed pseudo-first order kinetics. The obtained experimental data were analysed with response surface methodology (RSM) using Design Expert Software.

The current study focuses on the performance of Solar Greenhouse Dryer for drying of grapes for raisin making in Solar Dryer and Open sun condition in Western Maharashtra.  The Maharashtra state ranks first in the production of grapes, probably Western Maharashtra produces nearly 800 thousand tons of grapes every year. The major wastage of grapes is due to low sugar content, glossy appearance, shrinkage, excess water in berry, scorching and size variation. Therefore, there is a need to preserve the grapes by drying and making raisins for a non-seasonal requirement. The experiment was conducted for drying of grapes in Solar Greenhouse Dryer and Open Sun condition from 1st of April to 4th of April for 48 hours. The initial weight of the grapes to be dried was 500 grams for both Solar Greenhouse Dryer and open sun drying conditions. The experiment was conducted at Bahe, Borgaon, Tal-Walwa, Dist- Sangli, Maharashtra, India located at 17.115o N and 74.33o E.  The main aim of using DOE i.e., Response Surface Modelling is to get an optimum region for drying of grapes in Solar Greenhouse Dryer, from the Surface plot; the region of maxima and minima was obtained.

The enzymatic transesterification of Atlantic salmon (Salmo salar) oil was carried out using Novozym 435 (immobilized lipase from Candida antartica) to produce biodiesel. A response surface modelling design was performed to investigate the relationship between biodiesel yield and several critical factors, including enzyme concentration (5, 10, or 15%), temperature (40, 45, or 50 °C), oil/alcohol molar ratio (1:3, 1:4, or 1:5) and time (8, 16, or 24 h). The results indicated that the effects of all the factors were statistically significant at p-values of 0.000 for biodiesel production. The optimum parameters for biodiesel production were determined as 10% enzyme concentration, 45 °C, 16 h, and 1:4 oil/alcohol molar ratio, leading to a biodiesel yield of 87.23%. The step-wise addition of methanol during the enzymatic transesterification further increased the biodiesel yield to 94.5%. This is the first study that focused on Atlantic salmon oil-derived biodiesel production, which creates a paradigm for valorization of Atlantic salmon by-products that would also reduce the consumption and demand of plant oils derived from crops and vegetables.

Nine-link type double-toggle mold/die clamping mechanisms are widely used in modern injection molding machines and die casting machines in order to provide sufficient mold/die clamping force for counteracting the pressure occurred inside molds/dies. In this paper, the analysis and experimental evaluation of mechanical errors in nine-link type double-toggle mold/die clamping mechanisms are presented. The kinematic error equations of the output link (i.e., the moving platen) caused by dimensional errors (or tolerances) of link members are derived analytically through the concept of tolerance sensitivity analysis. Evaluation indices based on the asymmetry of the mold/die clamping mechanism caused by mechanical errors are established. A case study is then given to demonstrate the derived analytical equations and the established evaluation indices. Subsequently, a prototype for performing the experimental evaluation is conceptually designed and was actually constructed. Experiments were conducted for evaluating the quantitative influence of mechanical errors on the operating performance of the constructed mold/die clamping mechanism. According to the experimental results, response surface modelling for benefiting the constructed mold/die clamping mechanism with better operating performance could be performed. The presented research results will be helpful in the tolerance analysis and mechanical error detection of nine-link type double-toggle mold/die clamping mechanisms.

In this work, a sensitive and efficient voltammetric biosensor was introduced for differential pulse voltammetric (DPV) determination of dibutyl phthalate, dimethyl phthalate, di(2-ethylhexyl)phthalate and dicyclohexyl phthalate in aqueous solutions.