in this research, a rapid, reliable and selective dispersive liquid-liquid microextraction (dllme) followed by direct injection of microdroplet to graphite furnace atomic absorption spectrometry (gf-aas) method for the determination of ultra-trace amounts of ag(i) was developed. effect of the important experimental parameters on the extraction efficiency of ag(i) was investigated using response...

background and objective: glucoamylase is a potent starch degrading enzyme whose cheap production has been an area of research. its production by aspergillus niger in solid-state fermentation was studied using dried garden pea peel as a substrate, which enormously reduced the production cost. the current study intended to produce glucoamylase by a cost-effective strategy and exhaustively charac...

tannase has several important applications in food, feed, chemical and pharmaceutical industries. in the present study, production of tannase by mutant strain, penicillium sp. ez-zh390, was optimized in submerged fermentation utilizing two statistical approaches. at first step, a one factor at a time design was employed to screen the preferable nutriments (carbon and nitrogen sources of the med...

incorporation of functional foods and nutraceuticals such as carotenoids which suffer from poor water solubility and low bioavailability into nano-sized delivery systems can improve their solubility, stability and oral bioavailability. the aim of this study was to prepare β-carotene nanodispersion and investigate the effects of preparation parameters by means of response surface methodology usi...

conclusions we found ccd and rsm very effective in optimizing hib culture conditions, and hib biomass production was greatly influenced by ph and incubation temperature. therefore, optimization of the growth factors to maximize hib production can lead to 1) an increase in bacterial biomass and prp productions, 2) lower vaccine prices, 3) vaccination of more susceptible populations, and 4) lower...

in design of experiments, analysis and identifying those variables that affect the outputs are of interest. response surface methodology is a mathematical-statistical method to optimize the experiment outputs. this method tries to find the best response levels by optimizing the design variables called factors. in many engineering applications, robust design has become the most important issues....

conclusions the results of this study show that it is possible to remove nitrate, and its intermediates from waste water. regarding the desirability of the process, the field scale study is proposed. results the results showed that by applying electric current of 0.14 a for 120 minutes, the nitrate content would reduce down to 97%. the obtained r2 for the nitrate removal model was higher than 0...

functionally graded aluminium/zirconia metal matrix composite was fabricated using stir casting technique followed by horizontal centrifugal casting process and a hollow cylindrical functionally graded composite (150 x 150 x 16 mm) was obtained with centrifuging speed of 1200 rpm. the microstructural evaluation and hardness test was carried out on the outer and inner surface of the functionally...

low grade grape juice concentrate was used as carbon source for xanthan production. significant factors affecting xanthan concentration, productivity and viscosity were investigated using plackett-burman design. based on the obtained results, carbon and nitrogen concentrations, inoculum size and agitation rate, were assumed as significant factors. broth culture viscosity and xanthan concentrati...

with the huge global and wide range of attention placed upon quality, promoting and optimize the reliability of the products during the design process has turned out to be a high priority. in this study, the researcher have adopted one of the existing models in the reliability science and propose a bi-objective model for redundancy allocation in the series-parallel systems in accordance with th...