Search results for "Row"

The Forgotten Representatives of the School of Mathematics in Sciences of Management

2017

Szybki rozwój technologii, wzrost poziomu życia i zmiany demograficzne przyczyniają się do dynamicznych zmian zachodzących we współczesnym społeczeństwie. Specjaliści w dziedzinie demografii, zwracają szczególną uwagę na zjawisko „starzejącego się społeczeństwa”, co przyczyni sie do wzrostu zapotrzebowania na usługi medyczne świadczone przez lekarzy specjalizujących się w leczeniu ludzi starszych, oraz miejsca w ośrodkach opiekuńczo-leczniczych (sanatoriach czy hospicjach). Głównym celem niniejszego opracowania była ocena pozycji Polski na tle krajów Unii Europejskiej na podstawie wybranych wskaźników charakteryzujących system opieki zdrowotnej. W badaniach starano sie odpowiedzieć na pytan…

Détection des ruptures de fibres et du délaminage dans les composites verre/époxy et carbone/époxy à l'aide de structures propagatives dans la gamme …

2009

National audience; On présente dans cet article la détection de ruptures de fibre et du délaminage dans les composites unidirectionnels verre/époxy et carbone/époxy en utilisant des structures propagatives électromagnétiques dans la gamme des micro-ondes.

A microwave cylindrical cavity made of bulk MgB2 superconductor produced by reactive liquid Mg infiltration process

2007

Dielectric properties of myoglobin at 10 GHz by microwave cavity perturbation measurements

2010

We report on the temperature dependence, at microwave (mw) frequency, of the imaginary part of the dielectric constant (En) in myoglobin powder samples with different hydration levels (h). The measurements have been performed by the cavity perturbation technique, in the range of temperature 80-345 K. The sample is located inside a glass capillary along the axis of a cylindrical copper cavity, resonating in the TE011 mode at 9.6 GHz, where the mw electric field has a node. By measuring the variation of the quality factor of the resonant cavity, one can extract the imaginary part of the dielectric constant. At temperatures higher than 230 K we observe an evident increase of the dielectric los…

Microwave response of bulk MgB2 samples of different granularity

2006

The microwave response of three high-density bulk MgB2 samples has been investigated in the linear and nonlinear regimes. The three samples, characterized by different mean size of grains, have been obtained by reactive infiltration of liquid Mg in powdered B preforms. The linear response has been studied by measuring the microwave surface impedance; the nonlinear response by detecting the power radiated by the sample at the second-harmonic frequency of the driving field. Our results suggest that bulk MgB2 prepared by the liquid Mg infiltration technique is particularly promising for manufacturing resonant cavities operating at microwave frequencies.

Green conditions for the Suzuki reaction using microwave irradiation and a new HNT- supported ionic liquid-like phase (HNT-SILLP) catalyst

2014

A new catalytic system based on modified halloysite nanotubes was employed in the Suzuki reaction under microwave irradi- ation. A set of solvents, times and bases was screened and the best experimental conditions were obtained when the reactions were carried out for 10 min in water–ethanol at 120 °C in presence of K2CO3 as base. Good recyclability was observed. The new catalytic system was employed using either 1 mol% or 0.1 mol%. The palladium catalyst displayed good activity, allowing the synthesis of several biphenyl compounds in high yield working with only 0.1 mol% palladium loading. The application of mi- crowave irradiation decreased the reaction time and also improved conversion wi…

Determination of metal concentrations in certified plastic reference materials after small-size autoclave and microwave-assisted digestion followed w…

2017

Abstract The digestion methods for the determination of As, Cd, Cr, Pb, Sb, Sn and Zn concentrations in plastic samples using microwave-assisted digestion (MW-AD) and small-size autoclave digestion was developed. The certified polyethylene, polypropylene, polyvinyl chloride and acrylonitrile butadiene styrene certified reference materials were used in order to find digestion method working properly for several sample matrices. Efficiency of the digestion methods was evaluated by analyzing the residual carbon in digests by TOC analyzer. MW-AD using a mixture of 7 mL of HNO 3 and 3 mL of H 2 O 2 as a digestion solution resulted in excellent recoveries for As, Cd, Pb, Sb and Zn, and were in th…

Antioxidant activity and sensory attributes of tomatoes dehydrated by combination of microwave and convective heating

2013

Tomato halves were dried in a combined microwave-hot air system. Drying experiments were carried out by applying the microwave energy (0.5 W/g) at the beginning of the dehydration process (for 2 and 3.5 hours); simultaneously combining microwave (0.25 W/g) with convective hot-air drying (70°C); and by applying only convective hot air at 70°C. The combined microwave-hot air heating reduced significantly the drying time (up to 50 %), if compared with the only convective system. Simultaneous convective and microwave heating allowed besting preserving antioxidant activity of dried tomatoes, by minimizing lycopene and phenols losses, while ensuring satisfied texture characteristics and less perc…

Investigation on the stability of dispersion of zirconia nanoparticles prepared by microwave- hydrothermal synthesis

2005

Difficulties in reproducing the performances of nanoparticles dispersions are obstructive for the progress of the nanotechnology. A plausible reason for this variability is the lack of the control of the stability as well as the dimensions of the nanoparticles in the dispersions. In this work we report results of investigations on the stability of zirconia nanoparticles in aqueous medium, monitoring nanoparticles sizes by means of Transmission Electron Microscopy (TEM), Dynamic Light Scattering (DLS). Nanocrystalline zirconia powders, prepared by microwave-hydrothermal synthesis, were determined to be 6-8 nm in size by TEM observations. By using DLS technique the as-prepared dispersions wit…

Stepping up to strike: a union mobilization case study of Polish migrant workers in the Netherlands

2015

This article examines a union mobilization of Polish temporary agency workers in the Netherlands. The case study contributes to the migrant organizing literature a micro-level account of the dynamics of mobilization from the viewpoint of the migrants and organizers involved. The findings emphasize the importance of key actors in building solidarities within and between different groups of workers in fragmented workplaces, with implications for unions seeking new ways to respond to changing employment practices. This study highlights some of the possibilities and limitations of organizing among contractually fragmented workforces.