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排序方式: 共有174条查询结果,搜索用时 31 毫秒
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Christina Siakati Alexios P. Douvalis Panagiotis Ziogas Arne Peys Yiannis Pontikes 《Journal of the American Ceramic Society》2020,103(3):2173-2184
Aiming to reduce the carbon dioxide emissions associated with cement production, alternative binders such as inorganic polymers currently receive substantial attention and slags from the non-ferrous metallurgy are promising precursors. However, studies that correlate their chemistry and crystallinity with the newly formed binder remain limited. In this work, the effect of three different solidification methods on glass formation and reactivity of FeOx–SiO2 slags, as well as on the molecular structure of the resultant Fe-rich inorganic polymers, was investigated. The inorganic polymers were synthesized by mixing the slags (approximate molar ratio FeO/SiO2 = 1.6) with an alkali silicate solution (molar ratios SiO2/Na2O = 1.6 and H2O/Na2O = 25). Results demonstrated that higher cooling rates promoted higher glass formation and faster reaction kinetics when the slags were activated. 57Fe Mössbauer spectroscopy indicated that all the slags consisted predominantly of Fe2+ ions with a minor amount of Fe3+ ions, regardless of the variability in glass content. The binder phase of all inorganic polymers consisted of iron in both Fe2+ and Fe3+ states, after 28 days of curing. After pulverizing the inorganic polymer pastes and exposing the powder to air for 28 additional days, the Fe2+ state in the binder transformed to Fe3+. The compressive strength evolution of the three slags showed that the 2-day strength was higher for the samples with a higher amorphous fraction, while after 28 days, this influence was less pronounced. 相似文献
3.
Maria Pikoula Matthew B. Tessier Robert J. Woods Yiannis Ventikos 《Microfluidics and nanofluidics》2018,22(2):21
Experiments have consistently revealed the pivotal role of the endothelial glycocalyx layer in vasoregulation and the layer’s contribution to mechanotransduction pathways. However, the exact mechanism by which the glycocalyx mediates fluid shear stress remains elusive. This study employs atomic-scale molecular simulations with the aim of investigating the conformational and orientation properties of highly flexible oligosaccharide components of the glycocalyx and their suitability as transduction molecules under hydrodynamic loading. Fluid flow was shown to have nearly no effect on the conformation populations explored by the oligosaccharide, in comparison with static (diffusion) conditions. However, the glycan exhibited a significant orientation change, when compared to simple diffusion, aligning itself with the flow direction. It is the tethered end of the glycan, an asparagine amino acid, which experienced conformational changes as a result of this flow-induced bias. Our results suggest that shear flow through the layer can have an impact on the conformational properties of saccharide-decorated transmembrane proteins, thus acting as a mechanosensor. 相似文献
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In this paper, we present a novel methodology for preference learning based on the concept of inductive transfer. Specifically, we introduce a nonparametric hierarchical Bayesian multitask learning approach, based on the notion that human subjects may cluster together forming groups of individuals with similar preference rationale (but not identical preferences). Our approach is facilitated by the utilization of a Dirichlet process prior, which allows for the automatic inference of the most appropriate number of subject groups (clusters), as well as the employment of the automatic relevance determination (ARD) mechanism, giving rise to a sparse nature for our model, which significantly enhances its computational efficiency. We explore the efficacy of our novel approach by applying it to both a synthetic experiment and a real-world music recommendation application. As we show, our approach offers a significant enhancement in the effectiveness of knowledge transfer in statistical preference learning applications, being capable of correctly inferring the actual number of human subject groups in a modeled dataset, and limiting knowledge transfer only to subjects belonging to the same group (wherein knowledge transferability is more likely). 相似文献
6.
Alex Galanis Yiannis Kourkoutas Chrysoula C. Tassou Nikos Chorianopoulos 《International journal of molecular sciences》2015,16(10):25141-25153
Lactobacillus plantarum 2035 and Lactobacillus plantarum ACA-DC 2640 are two lactic acid bacteria (LAB) strains that have been isolated from Feta cheese. Both display significant potential for the production of novel probiotic food products. The aim of the present study was the development of an accurate and efficient method for the molecular detection and identification of the above strains in a single reaction. A multiplex PCR assay was designed for each strain, based on specific primers derived from Random Amplified Polymorphic DNA (RAPD) Sequenced Characterized Amplified Region (SCAR) analysis. The specificity of the assay was tested with a total of 23 different LAB strains, for L. plantarum 2035 and L. plantarum ACA-DC 2640. The multiplex PCR assay was also successfully applied for the detection of the above cultures in yogurt samples prepared in our lab. The proposed methodology may be applied for monitoring the presence of these strains in food products, thus evaluating their probiotic character. Moreover, our strategy may be adapted for other novel LAB strains with probiotic potential, thus providing a powerful tool for molecular discrimination that could be invaluable to the food industry. 相似文献
7.
Konstantinos Ritos Yiannis Lihnaropoulos Stergios Naris Dimitris Valougeorgis 《传热工程》2013,34(13-14):1101-1107
A detailed study of pressure- and temperature-driven flows through long channels of triangular and trapezoidal cross sections is carried out. Due to the imposed pressure and temperature gradients there is a combined gas flow consisting of a thermal creep flow from the cold toward the hot reservoir and a Poiseuille flow from the high- toward the low-pressure reservoir. The formulation is based on the linearized Shakhov model subject to Maxwell boundary conditions, and it is solved numerically using a finite-difference scheme in the physical space and the discrete velocity method in the molecular velocity space. The results are valid in the whole range of the Knudsen number. In addition to the dimensionless flow rates, a methodology is presented to estimate for a certain set of input data the mass flow rates and the pressure distribution along the channel. Finally, special attention is given to the case of zero net mass flow and to the computation of the coefficient of the thermomolecular pressure difference. 相似文献
8.
Anne Lanfer Karin Bammann Kolja Knof Kirsten Buchecker Paola Russo Toomas Veidebaum Yiannis Kourides Stefaan de Henauw Dénes Molnar Silvia Bel-Serrat Lauren Lissner Wolfgang Ahrens 《Food quality and preference》2013,27(2):128-136
The present study investigated taste preferences in a sample of 1705 children aged 6 to 9 years from survey centres in Italy, Estonia, Cyprus, Belgium, Sweden, Germany, Hungary, and Spain and aimed to identify factors correlated with taste preference. Children’s preferences for varying levels of sucrose (sweet) in apple juice and fat, sodium chloride (salt) and monosodium glutamate (umami) in crackers were assessed using paired-comparison tests. Socio-demographics (age, sex, parental education), early feeding practises (breastfeeding, introduction of fruits), parenting behaviour (TV viewing, using food as a reward) and taste threshold sensitivity for sucrose (sweet), sodium chloride (salt), caffeine (bitter) and monosodium glutamate (umami) were investigated as possible correlates of taste preferences. Parents reported on socio-demographics, early feeding and parenting behaviour. Taste thresholds were determined via a paired-comparison staircase method. Country of residence was the strongest factor related to preferences for all four tastes. Taste preferences also differed by age. Preference for sugar and salt increased between 6 and 9 years of age while preference for monosodium glutamate decreased. The age differences remained significant even after adjustment for sex, country of residence, parental education and early feeding habits. Sex, parental education, early feeding habits, TV viewing, using food as a reward and taste thresholds were not consistently related to taste preferences among the survey centres. In summary, the results highlight the importance of culture and age in taste preferences in children younger than 10 years of age. 相似文献
9.
Symeon Papadopoulos Yiannis Kompatsiaris Athena Vakali Ploutarchos Spyridonos 《Data mining and knowledge discovery》2012,24(3):515-554
The proposed survey discusses the topic of community detection in the context of Social Media. Community detection constitutes
a significant tool for the analysis of complex networks by enabling the study of mesoscopic structures that are often associated
with organizational and functional characteristics of the underlying networks. Community detection has proven to be valuable
in a series of domains, e.g. biology, social sciences, bibliometrics. However, despite the unprecedented scale, complexity
and the dynamic nature of the networks derived from Social Media data, there has only been limited discussion of community
detection in this context. More specifically, there is hardly any discussion on the performance characteristics of community
detection methods as well as the exploitation of their results in the context of real-world web mining and information retrieval
scenarios. To this end, this survey first frames the concept of community and the problem of community detection in the context
of Social Media, and provides a compact classification of existing algorithms based on their methodological principles. The
survey places special emphasis on the performance of existing methods in terms of computational complexity and memory requirements.
It presents both a theoretical and an experimental comparative discussion of several popular methods. In addition, it discusses
the possibility for incremental application of the methods and proposes five strategies for scaling community detection to
real-world networks of huge scales. Finally, the survey deals with the interpretation and exploitation of community detection
results in the context of intelligent web applications and services. 相似文献
10.
Our analysis is based on data from a double-bounded dichotomous choice contingent valuation study implemented to elicit public attitudes towards renewable energy generation and their willingness to pay for the construction of a wind farm in the area of Messanagros in the island of Rhodes, Greece. Results indicate that there are significant positive values deriving from the proposed project. Respondents report a mean willingness to pay a premium in their bi-monthly electric bills of €8.86 for the sole purpose of the construction of the wind farm. The estimated economic benefits to the local population are weighed against the investment cost in a cost–benefit analysis to inform policy making and implications for EU energy policy are provided. 相似文献