formaldehyde in small quantities is commonly analyzed by spectrophotometric methods. one of the most-commonly used spectrophotometric techniques for this purpose is based on the reaction with chromotropic acid. because of its simplicity, sensitivity, selectivity and its low cost, it is still widely used. investigations for replacing the concentrated sulfuric acid with other acids or using more ...

a box-behnken design with three replicates was used for preparation and evaluation of eudragit vancomycin (vcm) nanoparticles prepared by double emulsion. the purpose of this work was to optimize vcm nanoparticles to improve the physicochemical properties. nanoparticles were formed by using w1/o/w2 double-emulsion solvent evaporation method using eudragit rs as a retardant material. full factor...

a rhamnolipid–type biosurfactant production by pseudomonas aeruginosa mm1011 was studied in a miniaturized shaken bioreactor. the operational parameters, affecting the biosurfactant production in shaken bioreactors, such as shaking frequency (200, 250, 300 rpm), filling volume (50, 75, 100 ml), and aeration rate (0.2, 0.6, 1 vvm), were optimized using response surface methodology. the optimizat...

environmental pollution by 2,4-dicholorphenol (2,4-dcp), commonly found in industrial wastewater has been a concern for humans over the past 50 years. garden radish peroxidase (grp) can eliminate this poisonous pollutant. the aim of this study was to apply an experimental response surface methodology (rsm) and central composite design (ccd) to optimize grp-based treatment in order to maximize ...

in this study fullerene functionalized using oleum (h2so4·so3), followed by the hydrolysis of the intermediate cyclosulfated fullerene as well as  an oxidizing agent was employed to functionalize the fullerenes. ruthenium was then added by the impregnation method or deposited on the functionalized fullerene. subsequent to this step, response surface methodology (rsm) was used to study the cumul...

in this work, hydrochloric acid is used to remove iron impurities in the bauxite ore contained in the diasporite mineral located in the sari region. the bauxite ore was calcined at different temperatures and times, and then dissolved in a hydrochloric acid solution. after determining the optimum calcination conditions in 1 h at 900 °c, the response surface methodology (rsm) with four factors in...

a hydrothermal method for preparation of nano-size zirconia has been studied to optimize the effective parameters (precursor concentration, temperature and time) using response surface methodology (rsm). the synthesized zirconia samples were characterized through x-ray diffraction (xrd), scanning electron microscope (sem) and transmission electron microscopy (tem) analyses to identify mean nano...

sclerotinia stem rot (ssr), caused by sclerotinia sclerotiorum, is one of the most important diseases of canola (brassica napus) in golestan province, the leading canola producer in iran. in order to assess the yield loss of canola caused by ssr, 80 fields were surveyed in four different regions of the province (gorgan, ali abad, kalaleh and gonbad) during 2006-2007, and ssr intensity was recor...

this study presents the synthesis of polyvinyl acetate (pvac) by solution polymerization and its partial hydrolysis to polyvinyl alcohol (pva) using alkaline alcoholysis. the influence of the molar ratio of hydrolysis catalyst (naoh) to pvac and the time and temperature of the saponification reaction on the degree of hydrolysis and molecular weight of the pva were investigated using response su...