657 research outputs found
Democratic diffusion failures or successful authoritarian protection? Central Asian undeclared policies vis-à-vis the 'Arab Spring'
No full textComparative evaluation of the composition of vegetable essential and fixed oils obtained by supercritical extraction and conventional techniques: a chemometric approach
No full textWe compared by a chemometric approach the composition of essential (EO) and fixed (FO) oils previously obtained from several vegetable matrices by supercritical CO2 extraction (CO2-SFE) and conventional techniques (n-hexane in a Soxhlet apparatus and hydrodistillation). A multivariate approach, by determining the principal components analysis (PCA) applied to data of FO fatty acids and EO volatile compounds generally indicated that the vegetable oils extracted with CO2-SFE tightly clustered with those obtained by conventional methods. The graphical distances calculated in the PCA plots between the score of each SFE oil and the corresponding conventional oil revealed that the CO2-SFE FO and EO profiles were quite similar to conventional oils, with the additional benefit of not having unwanted traces of solvent. SFE FO were more similar to conventional oils than SFE EO (mean values of calculated graphical distances were 0.83 and 1.46 for FO and EO, respectively). Our results strongly corroborate the role of CO2-SFE as a suitable, environmentally safe, efficient method alternative to the traditional ones for the extraction of natural vegetable oils for food and pharmaceutical applications
Spatial energy decay estimate in dynamical problems for a micropolar viscoelastic solid
No full textThis paper concerns some estimes of the energy for a micropolar viscoelastic solid in dynamical problems. First, under the assumptions that the solid occupies a semi-infinite cylinder and that the boundary values vanish only on the base, we estimate for any fixed t > 0, in terms of initial and boundary data, the energy of the portions of the solid at distance greater than z from the base and its norm in L^1(0, t). Finally these results are extended to more general domains under the hypothesis that the initial and boundary data have a bounded support. In our analysis we make use of a Maximal Free Energy which allows us to impose very mild restrictions on the relaxation functions
Are Foreign Migrants more Assimilated than Native Ones?
No full textThe paper compares the pattern of wage assimilation of foreigners with both native immigrants and local natives in Italy, a country with large internal and international migration. This comparison, not yet exploited, yields understanding of the role played by language and knowledge of social capital. We use the administrative dataset on dependent employment (WHIP), to estimate a fixed effect model of the weekly wages of males aged 18-45 with controls for selection in return migration and unobserved heterogeneity. The three groups of workers start their careers at the same wage level but, as experience increases, the wage profiles of foreigners and natives, both immigrants and locals, diverge. A positive selection in the returns prevails, so that the foreign workers with lower wages are the most likely to stay in Italy. Also an “ethnic” skill differential emerges and a negative status dependence for those entering at low wage level.Migration, Assimilation, Wage differential.
Extraction of volatile fractions and carotenoids from orange and kumquat peel by supercritical carbon dioxide
No full textComparative analysis of the oil and supercritical CO2 extract of Artemisia arborescens L. and Helichrysum splendidum (Thunb.) Less
No full textComparative analysis of the oil and supercritical CO2 extract of Elettaria cardamomum (L.) Maton
No full textSpatial decay estimate in steady motion of a micropolar fluid in a pipe
No full textThe purpose of this paper is to dela with the entry flow problem for a micropolar fluid in steady motion in a semi-infinite cylinder pipe.The problem to be studied is "end effect" involving comparison between two motion: the Poiseuille flow (basic flow) and another flow with the same velocity flux. Our main result is an explicit estimate which establishes the rate of exponential decay, with axial distance z from the entry, of the dissipation energy of the perturbation thus providing a qualitative description of the flow development. We find that, under mild hypothesis on the asymptotic behavior of the fields and a smallness assumption on the velucity flux, the flow tends to the Poiseuille flow in the energy norm as z tends to infinity. We give also an upper bound for the perturbation energy through the data of the problem
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