Antioxidant effects of Rosemary extract on the accelerated degradation of ethylene-propylene-diene monomer

Abstract The goal of this paper is the qualification of natural antioxidants (rosemary extract, capsaicin, quercetin or oleanolic acid) playing as antioxidant. The stabilization activities were investigated in several formulations based on ethylene-propylene-diene-terpolymer (EPDM) in pristine state or after -irradiation, when the accelerated degradation scission of polymer macromolecules followed by the mitigation of oxidation. Three evaluation procedures: chemiluminescence, FTIR spectroscopy and thermal analysis were applied for the characterization of the stability contribution. The durability of studied EPDM formulations is discussed for the assessment of material life. The improved behavior of structured hybrids useful for the optimization application regimes is essentially based on the antioxidant properties of polyphenolic components in the cases of natural antioxidant

Kinetics of the Non-isothermal Degradation of POSS/EPDM Hybrids Composites

Polyhedral Oligomeric Silsesquioxane (POSS)/Ethylene-propylene-diene monomer (EPDM) composite, at 3% wt of POSS, is prepared by the evaporation of solvent (CHCl3) from polymer/filler system at room temperature and is investigated, by the means of thermogravimetric analysis (TGA), and the obtained TGA data are treated by the Kissinger method to get the apparent activation energy (Ea) of degradation. The results obtained for the composites, at different levels of irradiation, are discussed and compared with each other and with those obtained for pristine EPDM. A good improvement of the thermal stability, with respect to the neat polymer, is found showing the effect of the POSS molecules on the degradation rate. A classification among the samples at different levels of radiations is also drawn up, showing also in this case, the beneficial effect of the POSSs presence

The assessment of thermal and radiation stability of UHMWPE

Preirradiated ultrahigh molecular weight polyethylene (UHMWPE) was subjected to other cycle of γ-exposure in order to explain the behavior of this material after radiation processing. The oxygen uptake investigation was selected for the characterization of thermal stability of multisession irradiation. The long life radicals promote crosslinking or oxidative degradation depending on the second irradiation dose and on the environmental conditions. The main kinetic parameters: oxidation period and oxidation rate were evaluated depicting the availability of radiochemical processing of UHMWPE for further long term applications. Irradiation of UHMWPE in salt solution reveals the improvement in the thermal strength for low exposure doses

Ecosystem-bedrock interaction changes nutrient compartmentalization during early oxidative weathering

Ecosystem-bedrock interactions power the biogeochemical cycles of Earth's shallow crust, supporting life, stimulating substrate transformation, and spurring evolutionary innovation. While oxidative processes have dominated half of terrestrial history, the relative contribution of the biosphere and its chemical fingerprints on Earth's developing regolith are still poorly constrained. Here, we report results from a two-year incipient weathering experiment. We found that the mass release and compartmentalization of major elements during weathering of granite, rhyolite, schist and basalt was rock-specific and regulated by ecosystem components. A tight interplay between physiological needs of different biota, mineral dissolution rates, and substrate nutrient availability resulted in intricate elemental distribution patterns. Biota accelerated CO2 mineralization over abiotic controls as ecosystem complexity increased, and significantly modified stoichiometry of mobilized elements. Microbial and fungal components inhibited element leaching (23.4% and 7%), while plants increased leaching and biomass retention by 63.4%. All biota left comparable biosignatures in the dissolved weathering products. Nevertheless, the magnitude and allocation of weathered fractions under abiotic and biotic treatments provide quantitative evidence for the role of major biosphere components in the evolution of upper continental crust, presenting critical information for large-scale biogeochemical models and for the search for stable in situ biosignatures beyond Earth.Comment: 41 pages (MS, SI and Data), 16 figures (MS and SI), 6 tables (SI and Data). Journal article manuscrip

SHREC 2011: robust feature detection and description benchmark

Feature-based approaches have recently become very popular in computer vision and image analysis applications, and are becoming a promising direction in shape retrieval. SHREC'11 robust feature detection and description benchmark simulates the feature detection and description stages of feature-based shape retrieval algorithms. The benchmark tests the performance of shape feature detectors and descriptors under a wide variety of transformations. The benchmark allows evaluating how algorithms cope with certain classes of transformations and strength of the transformations that can be dealt with. The present paper is a report of the SHREC'11 robust feature detection and description benchmark results.Comment: This is a full version of the SHREC'11 report published in 3DO

Acceptance and Use of E-Learning Based on Cloud Computing: The Role of Consumer Innovativeness

Cloud computing and E-learning are the inevitable trend of computational science in general, and information systems and technologies in specific.However, there are not many studies on the adoption of cloud-based E-learning systems. Moreover, while there are many papers on information system adoption as well as customer innovativeness, the innovativeness and adoption in the same model seems to be rare in the literature. The study combines the extended Unified Theory of Acceptance and Use of Technology (UTAUT2) and consumer innovativeness on the adoption of E-learning systems based on cloud computing. A survey was conducted among 282 cloud-based E-learning participants and analyzed by structural equation modeling (SEM). The findings indicate that the adoption of cloud-based E-learning is influenced by performance expectancy, social influence, hedonic motivation, and habit. Interestingly, although innovativeness is not significant to use intention, it has a positive effect on E-learning usage which is relatively new in Vietnam