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Size Analyzer (size + analyzer)
Kinds of Size Analyzer Selected AbstractsEffects of ultrasound in coating nano-precipitated CaCO3 with stearic acidASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 5 2009K. W. Kow Abstract Nano-Precipitated CaCO3 (NPCC) are coated with stearic acid to improve its dispersion in polymer as well as to reduce agglomeration. In this work, coating was done by wet method using ethanol. Ultrasonication was applied to NPCC to de-agglomerate micron size NPCC into smaller size. Effects of amplitude, temperature and energy input of ultrasonication was investigated. The amplitude was varied from 60% to 100% whereas temperature was varied from 5°C to 45°C. The energy input was stressed up from 3.6 kJ to 180 kJ. Mean diameter of NPCC were observed by using Particle Size Analyzer and Transmission Electron Microscopy (TEM). It was found that mean diameter of NPCC do not vary significantly with temperature. Mean diameter of NPCC, however, decreases exponentially with the energy input. Comparisons were done on NPCC coated with others methods such as dry ball milling and aqueous coating. TEM images show that coating NPCC with ultrasonication is more uniform than other methods. In addition, first derivative mass loss with temperature (DTG) reveals that NPCC coated with ultrasonication do not contain excessive free acid as exhibited by those coated in aqueous and dry ball milling. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd. [source] Preparation and in vitro release of D,L -tetrahydropalmatine-loaded graft copolymer nanoparticlesJOURNAL OF APPLIED POLYMER SCIENCE, Issue 6 2008Yinglei Zhai Abstract D,L -tetrahydropalmatine (THP)-loaded poly{[,-maleic anhydride-,-methoxy-poly(ethylene glycol)]- co -(ethy cyanoacrylate)} (PEGECA) amphiphilic graft copolymer nanoparticles (PEGECAT NPs) were prepared by the nanoprecipitation technique. The effects of solvent property, temperature, copolymer composition, and drug feeding on the drug-loaded amount and size of PEGECAT NPs were investigated. The morphological structure of PEGECAT NPs was characterized by transmission electron microscopy (TEM), proton nuclear magnetic resonance (1H NMR), and the size was measured by laser particle size analyzer (LPSA). In vitro release behaviors of drug from PEGECAT NPs were examined by high-pressure liquid chromatography (HPLC). The results demonstrate that PEGECAT NPs take on a spherical morphology with an inner core and outer shell before and after in vitro release. THP can be incorporated into the hydrophobic core of PEGECAT NPs and the drug-loaded amount is higher than 5%. The release of THP from PEGECAT NPs is initially fast and then slows down. The accumulated release is lower than 40% after 48 h. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] Effect of Components Extracted from Okara on the Physicochemical Properties of Soymilk and Tofu TextureJOURNAL OF FOOD SCIENCE, Issue 2 2007Kyoko Toda ABSTRACT:, The physicochemical properties of soymilk and the texture of tofu were compared with regard to 2 kinds of soymilk, one of which was prepared by squeezing homogenates before heating and the other was prepared by squeezing after heating raw soymilk with okara, residue of soymilk production. Relative particulate protein content and viscosity were higher and pH was lower in the soymilk prepared by the latter method, in which liberated lipid bodies were decreased and more lipids were precipitated with protein after centrifugation, suggesting a change in the interaction between proteins and lipids. A difference in the distribution of proteins and lipids was also implied by analysis with a laser particle size analyzer. The breaking stress of tofu made with 0.30% glucono-delta-lactone increased in accordance with an increase in particulate protein. The calcium and magnesium contents increased in soymilk prepared by squeezing after heating with okara. Viscosity was slightly increased and pH decreased by adding calcium to the soymilk, but the particulate protein content and breaking stress of tofu did not increase significantly. To examine the effect of macromolecules, okara was extracted by boiling and dialyzed. Viscosity and particulate protein content in soymilk increased as the dialyzed extracts of the okara were added. The breaking stress of tofu was increased by adding the dialyzed extracts but excessive amounts of the extracts resulted in softer tofu. Spectra of Fourier-transform infrared spectroscopy and electrophoresis-separated patterns of proteins indicated that the dialyzed extracts contained mainly polysaccharides and the Basic 7S globulin protein. [source] Experimental and numerical investigation of the precipitation of barium sulfate in a rotating liquid film reactorAICHE JOURNAL, Issue 8 2009Shengchang Guo Abstract Precipitation of nanosized barium sulfate in a rotating liquid film reactor (RLFR) has been investigated experimentally and through simulations based on the computational fluid dynamics technique including the population balance equation coupled with the Navier,Stokes equations, renormalization group k,, model equations, and species transport equations. A comparative experiment was carried out involving conventional precipitation in a flask. The structure of the precipitate was identified by powder X-ray diffraction (PXRD), which showed that the crystals obtained using the RLFR were smaller in size than those obtained in the flask. Transmission electron microscopy (TEM) images demonstrated that the crystals produced by the two different processes had different morphologies. Further detailed experiments involving varying the operating parameters of the RLFR were performed to investigate the effects on crystal size distribution (CSD). Increasing the speed of the rotor in the RLFR in the range 1000,5000 rpm or increasing the rotor-stator gap in the range 0.1,0.5 mm resulted in a decrease in particle size and narrower particle size distributions. The simulation results suggested that turbulent effects and reaction processes in the effective reactor space were directly related to rotor speed and rotor-stator gap. The simulated volume weighted mean diameter and CSD of particles of barium sulfate were almost identical to the corresponding experimental results obtained using TEM and laser particle size analyzer. The effects of other parameters such as the Kolmogorov scale and competition between induction time and mixing time are also discussed. © 2009 American Institute of Chemical Engineers AIChE J, 2009 [source] Preparation of a Monodispersed Suspension of Barium Titanate Nanoparticles and Electrophoretic Deposition of Thin FilmsJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 8 2004Juan Li A transparent and stable monodispersed suspension of nanocrystalline barium titanate was prepared by dispersing a piece of BaTiO3 gel into a mixed solvent of 2-methoxyethanol and acethylacetone. The results of high-resolution transmission electron microscopy (HR-TEM) and size analyzer confirmed that the BaTiO3 nanoparticles in the suspension had an average size of ,10 nm with a narrow size distribution. Crystal structure characterization via TEM and X-ray diffraction indicated BaTiO3 nanocrystallites to be a perovskite cubic phase. BaTiO3 thin films of controlled thickness from 100 nm to several micrometers were electrophoretic deposited compactly on Pt/Ti/SiO2/Si substrates. The deposited thin film had uniform nanostructure with a very smooth surface. [source] Synthesis and characterization of poly(butyl acrylate- co -ethylhexyl acrylate)/ poly(vinyl chloride)[P(BA-EHA)/PVC] novel core-shell modifier and its impact modification for a poly(vinyl chloride)-based blendPOLYMER ENGINEERING & SCIENCE, Issue 6 2010Mingwang Pan Synthesis of poly(butyl acrylate-co-ethylhexyl acrylate)-core/poly(vinyl chloride)-shell [P(BA-EHA)/PVC] used as a modifying agent of PVC via semicontinuous seeded emulsion copolymerization is reported here. Diameter distributions and morphology of the composite latex particles were characterized with the aid of particle size analyzer and transmission electron microscopy (TEM). The grafting efficiency (GE) and grafting ratio (GR) of vinyl chloride (VC) grafted onto the P(BA-EHA) with varying content of crosslinking agent and core-shell ratios were investigated. TEM studies indicated that the P(BA-EHA)/PVC latex particles have core-shell structure, and the P(BA-EHA) rubbery particles in blending materials were uniformly dispersed in PVC matrix. Dynamic mechanical analysis (DMA) results revealed that the compatibility between the P(BA-EHA) and the PVC matrix was significantly improved due to the presence of the P(BA-EHA)-grafted-VC copolymer. The notched impact strength of the blending material with 3 wt% of rubber content was seven times that of the PVC. Linear regressions of mechanical properties as loading of the modifier were made. The resulting data of notched impact strength and elongation at break for the blending materials deviated significantly from regression lines within 3,4.5 wt% of the P(BA-EHA) content. The PVC blends modified by the modifier exhibited good toughness and easy processability. POLYM. ENG. SCI., 2010. © 2009 Society of Plastics Engineers [source] Population balance modeling of the conidial aggregation of Aspergillus nigerBIOTECHNOLOGY & BIOENGINEERING, Issue 2 2008P.-J. Lin Abstract Numerous biotechnological production processes are based on the submerse cultivation of filamentous fungi. Process design, however, is often hampered by the complex growth pattern of these organisms. In the morphologic development of coagulating filamentous fungi, like Aspergillus niger, conidial aggregation is the first step of filamentous morphogenesis. For a proper description of this phenomenon it is necessary to characterize conidial populations. Kinetic studies performed with an in-line particle size analyzer suggested that two distinct aggregation steps have to be considered. The first step of conidial aggregation starts immediately after inoculation. Both the rate constants of formation and disintegration of aggregates have been determined by measuring the concentration of conidia at the beginning of the cultivation and the concentration of particles at steady state during the first hours of cultivation. In contrast to the first aggregation step, where the collision of conidia is presumed to be responsible for the process, the second aggregation step is thought to be initiated by germination of conidia. Growing hyphae provide additional surface for the attachment of non- germinated conidia, which leads to a strong decrease in particle concentration. The specific hyphal length growth rate and the ratio of particle concentration to the growing adhesion hyphal surface are decisive matters of the second aggregation step. Both aggregation steps can be described by population dynamics and simulated using the program package PARSIVAL (PARticle SIze eVALution) for the treatment of general particle population balances. Biotechnol. Bioeng. 2008;99: 341,350. © 2007 Wiley Periodicals, Inc. [source] | |||||||||||||