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991.
Organic coatings based on epoxy and polyurethane matrices containing polyaniline doped with dodecyl benzene sulfonic acid (Pani-DBSA) were prepared and applied over steel plates (SAE 1020). The plates were submitted to salt spray chamber for up to 30 days in order to evaluate the corrosion protection of these coatings. The properties of the coated plates were analyzed as a function of time by electrochemical impedance spectroscopy, open circuit potential, optical microscopy, and Raman spectroscopy. In general, results indicate a decrease in the electrical resistance, increase in capacitance and decrease in open circuit potential. Epoxy based coatings have improved performance when Pani-DBSA is used as pigment, whereas for the polyurethane coatings, Pani-DBSA seems to play an adverse effect. Raman spectroscopy indicates a possible chlorination of the epoxy matrix after 30 days exposure to salt spray chamber. 相似文献
992.
993.
Filiberto González Garcia Maria Elena Leyva Marcia Gomes Oliveira Alvaro Antonio Alencar De Queiroz Alexandre Zirpoli Simões 《应用聚合物科学杂志》2010,117(4):2213-2219
The mechanical and adhesive properties of epoxy formulations based on diglycidyl ether of bisphenol A cured with various aliphatic amines were evaluated in the glass state. Impact and uniaxial compression tests were used to determine the impact energy, elastic modulus and yield stress, respectively. The adhesion tests were carried out in steel–steel joints using single‐lap shear, T‐peel, and impact adhesive joints geometry. The better mechanical and adhesive behavior of the networks is obtained when exists high flexibility of chain between crosslink and/or high elastic modulus. The 1‐(2‐aminoethyl)piperazine epoxy network presents the best adhesive properties, high flexibility, and the largest impact energy. However, it possesses low elastic modulus and yield stress. Also, exhibits increases in peel strength and impact energy while reductions in lap shear strength. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 相似文献
994.
995.
996.
M. R. Gennero De Chialvo S. L. Marchiano A. J. Arvía 《Journal of Applied Electrochemistry》1984,14(2):165-175
The formation of Cu2O by the oxidation of Cu in alkaline solutions under various controlled potential conditions has been studied by potentiodynamic methods, the rotating ring disc technique and by employing colloidal Cu(OH)2 electrodes supported on vitreous carbon.The kinetics of the electrochemical reactions, both anodic and cathodic, are interpreted in terms of a complex reaction mechanism involving various intermediates participating in the phase oxide formation, (e.g. adsorbed OH, soluble Cu(I) and metal sites of different activity).Besides the electrochemical reactions the model includes various ageing and surface restructuring processes. The growth mechanism is envisaged to depend on the conditions of oxidation. 相似文献
997.
Nina Hammer Ingvar Kvande Wouter van Beek De Chen Magnus Rønning 《Topics in Catalysis》2007,45(1-4):25-29
In situ X-ray absorption spectroscopy (XAS) has been performed to investigate the active site on Au-based catalysts in the water-gas
shift (WGS) reaction. The surface area and hence the WGS activity is higher for AuTiO2 catalysts supported on carbon nanofibres (CNF) than TiO2. The WGS reaction rate depends on the Au coordination number with an apparent maximum close to eight which corresponds to
a particle size of approximately 2.5–3.0 nm. A likely cause for the changes in the electronic structure of Au is the adsorption
of CO on the surface, which also creates a small positive charge in the Au atoms. The catalytic activity significantly improves
when titania is present compared to Au deposited directly on CNF. 相似文献
998.
Microkinetic model for the pyrolysis of methyl esters: From model compound to industrial biodiesel
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Ruben De Bruycker Steven P. Pyl Marie‐Françoise Reyniers Kevin M. Van Geem Guy B. Marin 《American Institute of Chemical Engineers》2015,61(12):4309-4322
A tool for the generation of decomposition schemes of large molecules has been developed. These decomposition schemes contain radicals which can be eliminated from the model equations if both the μ‐hypothesis and the pseudosteady‐state approximation are valid. The reaction rate coefficients and thermodynamic parameters have been calculated by incorporating a comprehensive group additive framework. A microkinetic model for the pyrolysis of methyl esters with a carbon number of up to 19 has been generated using this tool. It is validated by comparing calculated and experimental yields of the pyrolysis of methyl decanoate and novel rapeseed methyl ester pyrolysis data in the temperature range from 800 to 1100 K and methyl ester partial pressure range from 1 × 10?3 to 1 × 10?2 MPa. This modeling frame work allows to not only assess the use of methyl ester mixtures as potential feedstock for olefin production but also their effect as blend‐in or trace impurity. © 2015 American Institute of Chemical Engineers AIChE J, 61: 4309–4322, 2015 相似文献
999.
Fish Oil and Olive Oil Supplementation in Late Pregnancy and Lactation Differentially Affect Oxidative Stress and Inflammation in Sows and Piglets
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Yong Shen Haifeng Wan Jiatao Zhu Zhengfeng Fang Lianqiang Che Shengyu Xu Yan Lin Jian Li De Wu 《Lipids》2015,50(7):647-658
This study was conducted to compare the effects of fish oil and olive oil supplementation in late pregnancy and during lactation on oxidative stress and inflammation in sows and their piglets. A total of 24 sows were fed a basal diet supplemented with additional corn starch (CON), fish oil (FO) or olive oil (OO). Sows fed an OO diet during late gestation had a higher piglet birth weight compared with CON‐fed and FO‐fed sows (P < 0.05). Furthermore, sows from the OO group had a higher milk fat content than sows from CON and FO groups, and a lower pre‐weaning mortality of piglets was observed in the OO group (P < 0.05). Maternal FO supplementation resulted in increased malondialdehyde concentration in sow plasma, colostrum, milk and piglet plasma than in CON and OO groups (P < 0.05). However, an increased total antioxidant capacity (T‐ACC) and activities of glutathione peroxidase (GSH‐Px) and total superoxide dismutase (T‐SOD) were also observed in the FO group (P < 0.05). Sows fed an OO diet had significantly decreased interleukin‐1β (IL‐1β), interleukin‐6 (IL‐6) and tumor necrosis factor‐α (TNF‐α) concentrations in milk compared with CON and FO fed sows (P < 0.05). Moreover, lower plasma IL‐1β and TNF‐α levels were observed in piglets from the OO group compared with the CON group (P < 0.05). Collectively, these results suggest that an OO diet is most beneficial in late gestation and during lactation in sows. However, FO increases the susceptibility to oxidative stress in sows and piglets. 相似文献
1000.
Jobin Jose Mamdouh A. Al‐Harthi Mariam Al‐Ali AlMa'adeed Jolly Bhadra Dakua Sadhan K. De 《应用聚合物科学杂志》2015,132(16)
Polymer nanocomposites based on poly(vinyl alcohol) (PVA)/starch blend and graphene were prepared by solution mixing and casting. Glycerol was used as a plasticizer and added in the starch dispersion. The uniform dispersion of graphene in water was achieved by using an Ultrasonicator Probe. The composites were characterized by FTIR, tensile properties, X‐ray diffraction (XRD), thermal analysis, and FE‐SEM studies. FTIR studies indicated probable hydrogen bonding interaction between the oxygen containing groups on graphene surface and the –OH groups in PVA and starch. Mechanical properties results showed that the optimum loading of graphene was 0.5 wt % in the blend. XRD studies indicated uniform dispersion of graphene in PVA/starch matrix upto 0.5 wt % loadings and further increase caused agglomeration. Thermal studies showed that the thermal stability of PVA increased and the crystallinity decreased in the presence of starch and graphene. FE‐SEM studies showed that incorporation of graphene increased the ductility of the composites. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41827. 相似文献