A rolling-sphere viscometer (RSV) was constructed and evaluated for monitoring apparent viscosit~'es of fermentation broths in sha'ke flasks or test tubes. The apparatus was calibrated by measuring translational velocities of magnetic stainless ste.el spheres (0.16-0.95 em diameter) rolling in N~wto­ nian viscosity standards (50-12.500 mPa's) on surfaces inclined 20° to 70°. The method was appl...

Telechelic associative polymers such as Hydrophobically modified ethoxylated urethanes (HEURs) are an important class of rheology additives used in many industrial fields allowing a precise control the rheology. To avoid use toxic isocyanates, more eco-friendly HEURs were synthesized based on cyclo-carbonate/amine addition reaction. hydroxyurethanes (HEHURs) thus obtained by aminolysis telechel...

The performance of different natural fibers (hemp, kenaf and bamboo) used to formulate composites with an alkali-activated matrix based on metakaolin is evaluated. Short were randomly dispersed up about 3% the binder weight, fresh cured properties derived determined. Up investigated fraction, it still possible obtain adequate workability without supply additional water or additives. Upon modifi...

Nutmeg seed oil is one of essential which unstable in storage. The stability nutmeg can be improved by being formulated into an emulgel with carbopol 940. This study was to determine the physical and SPF value vitro 940 as a gel base. made 10% concentration variation base, namely 0.60% (FI), 0.80% (FII), 1.0% (FIII). tested for including organoleptic, homogeneity, adhesion, dispersibility, visc...

Media composition and culture conditions for levan production by Bacillus mojavensis (BM-levan) were optimized using Plackett–Burman Box-Behnken designs. The yield was 0.44 g of per gram sucrose consumed. decomposition revealed an optimal temperature 228 °C, endothermic peak at 216.58 °C a melting enthalpy 49.28 J/g. rheological parameters the aqueous solutions from BM-levan determined accordin...

Unsteady oscillatory flow of generalized Burgers’ fluid in a circular channel tube in the porous medium is investigated under the influence of time-dependent trapezoidal pressure gradient given by an infinite Fourier series. An exact analytical expression for the solution for the fluid velocity and the shear stress are recovered by using the similarity arguments together with the integral trans...

water soluble amphoteric graft copolymers of polysaccharide were synthesized via grafting of cationic monomer onto the sodium carboxymethylcellulose ()cmc)( and then used as a shale stabilizer in the water-based drilling fluids. accordingly, five types of cmc-graft copolymers with different ratios of acrylamide am)( and diallyldimethylammonium chloride dadmac)( were synthesized. grafting of mon...