Papers by Keyword: Swelling

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Authors: Hang Yu, Lei Tao
Abstract: A novel method with two steps for preparing high efficiency fluorescence nanocrystals (NCs)-encoded microspheres was developed. First, a series of polystyrene (PS) microspheres from 1 μm to 5 μm in diameter were prepared by dispersion polymerization; then, after a swelling process with CdSe NCs of different size the PS microspheres were encoded quantitatively. This method for fluorescence-encoding of microspheres was shown to have the following outstanding characteristics: (1) An emulsion containing CdSe NCs and swelling agents (chloroform) are firstly used for introduction of NCs into microspheres. (2) The embedded nanocrystals remain their original properties and they are not simply absorbed onto the surface of the microspheres but being carried into the inner of microspheres and so the NCs cannot be released or leaked out easily. As-prepared fluorescence-encoded microspheres could conjugate with proteins by some further surface modification, so they have a great potential to be applied to such fields as biochemistry, molecular biology, cell biology, immunology, etc. In addition, the method could be operated easily and reproducibly.
Authors: G.İ. Öztürk, H.T. Vakos, W. Voelter, A. Taralp
Authors: Jae Young Choi, Ho Youn Kim, Jae Hong Park, Hae Do Jeong, Heonduc Seo
Authors: L. Aberkane-Mechebbek, S.F. Larbi-Youcef, M. Mahlous
Abstract: Hydrogel based on acrylamide and acrylic acid was synthesized and crosslinked by gamma radiation at an absorbed dose of 8 kGy. Swelling properties of the hydrogel in water and in methyl violet and Congo red solutions were investigated. The results showed that the swelling rate of the hydrogel depends on the pH and the ionic nature of the dye. Diffusion of water and dyes solutions within the hydrogel was found to be of non-Fickian character. Contrary to the swelling behavior, the capacity of the hydrogel to adsorb dyes seems to be higher at weak pHs. Concerning metal ions uptake, the results showed that adsorption of Cu2+ increases with pH increasing from pH1 to pH4.
Authors: Anne Lise Durier, Katell Derrien, Pierre Gilormini
Abstract: Diffusion of fluids in polymers may lead to swelling, which induces stress-diffusion coupling. A simple coupling model is considered, where boundary conditions only are altered, and it leads to a sigmoidal water-uptake curve for a plate in water. Several other models are studied, which are able to induce similar sorption curves by using various boundary conditions, but comparisons between other predictions of the models reveal significant differences. Eventually, none of the models considered is able to reproduce all features of the coupling model.
Authors: Xiao Xia Qiu, Jie Sun, Shu Jie Tong, Shi Jia Wang, Li Yuan Wu, Fang Yuan Cheng, Hai Ning Lv
Abstract: N-isopropylacrylamide was synthesized in a mixture of DMF and THF ( 7:3 in volume ratio) and characterized by FT-IR. The behavior of poly(N-isopropylacrylamide) chain was studied by spectrometer in mixtures of water with DMF and THF. Cononsolvency phenomena were found to be temperature-dependent, as demixing occurred upon increasing temperature. A significant shrinkage of polymer chains and deswelling of polymer gels, followed by phase separation, were observed for high water fractions.
Authors: V. Voyevodin, O. Borodin, V. Bryk, A. Kalchenko, A. Parkhomenko, G. Tolstolutskaya
Abstract: Mechanisms of degradation of physical-mechanical properties of PVI steels during irradiation are studied. Microstructure evidence of influence of irradiation temperature, dose and dose rate on processes of low-temperature swelling and embritllement of pressure vessel internal materials, 18Cr-10Ni-Ti steel, of reactor WWER 1000 are presented. Micro mechanisms of plastic deformation and steel failure in wide range of temperatures and irradiation doses are described. Analysis of influence of subsequent and simultaneous irradiation with beams of gas and heavy ions is carried out for investigation of influence of gaseous impurities that form through transmutation nuclear reactions on defected structure evolution under irradiation.
Authors: M.D. Mathew, K.A. Gopal, S. Murugan, B.K. Panigrahi, A.K. Bhaduri, T. Jayakumar
Abstract: Fuel cycle cost of sodium cooled fast reactors (SFRs) is strongly dependent on the in-reactor performance of core structural materials, i.e., cladding and wrapper tube materials of the fuel subassembly, which are subjected to intense neutron irradiation during service, leading to unique materials problems like void swelling, irradiation creep and helium embrittlement. In order to increase the burnup of the fuel and thereby reduce the fuel cycle cost, it is necessary to employ materials which have high resistance to void swelling as well as better high temperature mechanical properties. The Indian fast reactor program began with the commissioning of the 40 MWt Fast Breeder Test Reactor (FBTR). The core structural material of FBTR is 20% cold worked 316 austenitic stainless steel (SS). For the 5000 Met Prototype Fast Breeder Reactor (PFBR) which is in an advanced stage of construction at Kalpakkam, 20% cold-worked alloy D9 (14Cr-15Ni-Ti SS) has been selected as the cladding and wrapper tube material for the initial core. The target burnup of the fuel is 100 GWd/t. Advanced austenitic stainless steel and oxide dispersion strengthened steels are being developed for achieving fuel burnup higher than 100 GWd/t. An advanced alloy D9 containing controlled amounts of titanium, silicon and phosphorous has been developed. This alloy named as IFAC-1 (Indian Fast Reactor advanced Clad-1) SS is aimed at thermal creep properties comparable to that of alloy D9, and superior void swelling resistance upto a target burn-up of about 150 GWd/t. The nominal chemical composition of IFAC-1 SS is 14Cr-15Ni-.25Ti-.75Si-.04P. The chemical composition has been optimized after extensive evaluation of the tensile, creep and microstructural stability of fifteen laboratory heats with different amounts of titanium, silicon and phosphorous. Void swelling behavior was studied using ion irradiation. IFAC-1 SS contains higher levels of low melting eutectic phase forming elements such as phosphorous, and so is susceptible to solidification cracking. Extensive pulsed TIG welding trials have been carried out on IFAC-1 SS/316LN SS weld joints with varied weld parameters to find out the feasibility of obtaining solidification crack-free welds and the optimum welding parameters have been established. This paper gives an overview of the development of this advanced core structural material for SFRs.
Authors: T. Mohanty, Narayan C. Mishra, K. Patnaik, L. Senapati, D. Kanjilal, G.K. Mehta
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