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  • 2005-2009  (1)
  • 2000-2004  (4)
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Year
  • 1
    Electronic Resource
    Electronic Resource
    Bingley : Emerald
    Pigment & resin technology 34 (2005), S. 275-281 
    ISSN: 0369-9420
    Source: Emerald Fulltext Archive Database 1994-2005
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Purpose - To evaluate the photochromic performance of photochromic compounds in polymer matrices. Design/methodology/approach - The epoxy resin doped with photochromic fulgide were prepared and the effect of UV irradiation were studied using spectrophotometer. The reversible reaction was effected using white light. The effect of heat was also determined. Findings - A film of fulgide 1-E doped in epoxy polymer was irradiated with UV light (366?nm), the film turned pink. The later colour was switched back to the original colour when the film was irradiated with a white light. The photocoloration and photobleaching obeyed first order rate equations with rate constants being 4.19×10-3?s-1 and 2.86×10-2?s-1, respectively. It was found that the film showed a good fatigue resistance. Another film was preheated at 80°C for 1-4?h. No change in the UV absorption spectra of the film was observed. Similarly, the photocoloration and photobleaching of the annealed film showed first order rate equations with rate constants being 8.77×10-3?s-1 and 4.02×10-2s-1, respectively. Interestingly, the photocoloration and photobleaching reactions of the annealed film were faster than those of the non-annealed film. Research limitations/implications - The epoxy resin doped photochromic fulgides described in the present paper was prepared and studied. The principle of study established can be applied to any type of resin or to any type of photochromic compounds. Practical implications - The photochromic materials developed can be used for different applications, such as coatings and holography. Originality/value - The method developed may be used to enhance the performance of photochromic materials.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science Ltd
    Journal of oral rehabilitation 30 (2003), S. 0 
    ISSN: 1365-2842
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: summary  The purpose of this investigation was to evaluate the tensile bond strengths of two impression material systems (polysulphide and polyvinyl siloxane) to two custom tray materials [autopolymerizing and visible light-cured (VLC) acrylic resin]. The effect of polymerizing the tray materials directly against wax spacer and tinfoil was evaluated for each material. Polymerizing tray materials against tinfoil significantly increased the bond strengths of polysulphide and polyvinyl siloxane impression materials to VLC and autopolymerizing acrylic resin tray materials. Polyvinyl siloxane VLC cured against tinfoil combination produced the strongest bond. The VLC resin tray material generated greater bond strength than autopolymerizing acrylic resin when polymerized against tinfoil.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1745-4522
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Response Surface Methodology (RSM) for optimization of carotene recovery from hydrolyzed palm olein (HCPOlein) in adsorption chromatography was carried out. The level and interaction of three independent variables was investigated: column temperature (50 to 60C), oil loading (25 to 200 g), and mobile phase flow rate (6 to 60 mL/min). Based on the response as percentage of carotene recovery from 50 g of HP-20 adsorbent, the optimum conditions were achieved at 200 g of oil loading, column temperature at 55C, and flow rate at 33 mL/min. Up to 98% of carotene recovery was obtained under these conditions. Interaction of oil-oil, oil-flow rate and flow rate-flow rate could enhance the percentage of carotene recovery. However, oil and flow rate as single factors could significantly reduce percentage of carotene recovery. Oil loading as a single factor could positively influence the amount of carotene adsorbed. However, flow rate as a single factor and oil-oil interaction could negatively influence the amount of carotene adsorbed. The mean of difference (MD) of the experimental and predicted data for percentage of carotene recovery and the amount of carotene adsorbed were very small, −0.0067 and 0.0133, respectively. The probability (P) value showed no significant lack-of-fit for both equations in this model.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of food lipids 9 (2002), S. 0 
    ISSN: 1745-4522
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Crude palm oil and crude palm olein were hydrolyzed with lipase from Candida rugosa to produce a free fatty acid (FFA) rich oil. The percentages of FFA produced and carotene degradation after the hydrolysis process were determined. The palm oil and hydrolyzed palm oil were subsequently subjected to column chromatography. Diaion HP-20 adsorbent was used for reverse phase column chromatography at 50C. Isopropanol or ethanol, and n-hexane were used as the first and second eluting solvents, respectively. The objective of hydrolyzing the palm oil was to produce more polar FFA-rich oil in order to enhance the nonpolar carotene bind to the nonpolar HP-20 adsorbent in the column chromatography process. Hydrolyzing palm oil with lipase from Candida rugosa gave 30- and 60-fold, respectively, of FFA in the crude palm oil and crude palm olein in 24 h at 50C. Approximately, 15.56 and 17.48% of carotene degraded in crude palm oil and crude palm olein, respectively. For column chromatography, using isopropanol or ethanol as the first eluting solvent, unhydrolyzed oil and hydrolyzed oil showed the carotene recovery infraction two (carotene-rich fraction) of about 36–37 and 90–96%, respectively. Over 90% of carotene recovery was obtained from
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1434-601X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. A folding potential describing the $\alpha$ -scattering on 16O over a broad energy range 25.8-146.0 MeV is constructed on the basis of $\alpha$ -like cluster and unclustered-nucleon configurations of 16O. The resulting potential does not need any renormalization to fit the angular distribution of elastic cross-sections. The effects of the repulsive part of $\alpha$ - $\alpha$ and $\alpha$ -nucleon interactions are investigated. The analysis suggests that both the $\alpha$ - $\alpha$ repulsive potential and the unclustered nucleonic configuration in the target are important to describe the scattering data over a broad range of incident energies. The root-mean-square radius for the 16O nucleus is deduced.
    Type of Medium: Electronic Resource
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