Demand for broadband access in Greece

As broadband access networks are relatively new in Greece, it is really difficult and involves great risk to determine the potential market for broadband services. The intent of this paper is to add to the discussion of delivering fixed broadband lines to customers in Greece taking into account regulation issues, the strategic movements of the market key players and the commonly admitted inequality of broadband access availability between urban and rural areas. In addition, using time-series analysis and examining the correlations between the number of fixed broadband lines and specific demographic factors for the past three years (mid 2006–mid 2009), an attempt to estimate empirically the forthcoming demand for broadband lines is conducted. Population’s income and effective competition are recognized as the strongest determinants of broadband development. In addition, it yields that demand for broadband will continue to have a positive trend for the years to come as people are becoming more and more familiar with new technologies, with youth being the pioneer to the use of innovative services that require broadband access.     

Effect of anilinopyrimidine resistance on aflatoxin production and fitness parameters in Aspergillus parasiticus Speare

Mutants of Aspergillus parasiticus resistant to the anilinopyrimidine fungicides were isolated at a high mutation frequency after UV-mutagenesis and selection on media containing cyprodinil. In vitro fungitoxicity tests resulted in the identification of two predominant resistant phenotypes that were highly (R₁-phenotype) and moderately (R₂-phenotype) resistant to the anilinopyrimidines cyprodinil, pyrimethanil and mepanipyrim. Cross-resistance studies with fungicides from other chemical groups showed that the highly resistance mutation(s) did not affect the sensitivity of R₁-mutant strains to fungicides affecting other cellular pathways. Contrary to that, a reduction in the sensitivity to the triazoles epoxiconazole and flusilazole, the benzimidazole carbendazim, the phenylpyrrole fludioxonil, the dicarboximide iprodione and to the strobilurin-type fungicide pyraclostrobin was observed in R₂-mutant strains. Study of fitness parameters of anilinopyrimidine-resistant strains of both phenotypic classes showed that all R₁ mutant strains had mycelial growth rate, sporulation and conidial germination similar to or even higher than the wild-type parent strain, while these fitness parameters were negatively affected in R₂ mutant strains. Analysis of the aflatoxin production showed that most R₁ mutant strains produced aflatoxins at concentrations markedly higher than the wild-type parent strain. A considerable reduction in the aflatoxin production was observed on cultured medium and on wheat grains by all R₂ mutant strains, indicating a possible correlation between fitness penalties and aflatoxigenic ability of A. parasiticus. The potential risk of increased aflatoxin contamination of agricultural products and their byproducts by the appearance and predominance of highly aflatoxigenic mutant strains of A. parasiticus resistant to the anilinopyrimidines is discussed.     

A phenomenological analysis of Mode I fracture of adhesively-bonded pultruded GFRP joints

The fracture behavior of adhesively-bonded pultruded joints was experimentally investigated under Mode I loading using double cantilever beam specimens. The pultruded adherends comprised two mat layers on each side with a roving layer in the middle. An epoxy adhesive was used to form the double cantilever beam specimen. The pre-crack was introduced in three different depths in the adherend in order to induce crack initiation and propagation between different layers and thus investigate the effect of these different crack paths on the strain energy release rate. Short-fiber and roving bridging increased the fracture resistance during crack propagation. Specific levels of critical strain energy release rates could be attributed to each of the crack paths, with their levels depending on the amount of short-fiber bridging and the presence of a roving bridge. The different levels of critical strain energy release rate could be correlated to the morphology of the fracture surface and the strain energy release rate can thus be determined visually without any measurement.     

Treating any polymer dissolved in water as polymer presenting a draining effect

The statistical segment length of a large number of flexible and rigid polymers dissolved in water is calculated. For these calculations, the constant value of the Flory??s parameter ?? (???=?2.6?×?10²³?cgs) along with its values obtained from an equation proposed for polymers exhibiting a significant draining effect (Colloid Polym Sci 273: 626?C632, 1995) are used. Applying the first approximation for ??, a very low statistical segment length for the polymers dissolved in water is obtained, while in the second case the statistical segment length is almost identical with the values obtained when these polymers are dissolved in an organic solvent. Moreover, we show that there is an optional application of the modified universal calibration of the gel permeation chromatography (J Polym Sci B Polym Phys 41: 707?C710, 2003), only if we use values of ?? obtained via the second approximation for polymers presenting a significant draining effect (Colloid Polym Sci 273: 626?C632, 1995).     

Dispersive liquid–liquid microextraction for the determination of organochlorine pesticides residues in honey by gas chromatography-electron capture and ion trap mass spectrometric detection

A simple dispersive liquid–liquid microextraction (DLLME) protocol for the determination of 15 organochlorine pesticides residues in honey is proposed. The selected pesticides were separated using gas chromatography and detected by electron capture (ECD) or ion trap mass spectrometry (GC-IT/MS). Several parameters affecting the extraction efficiency namely type and volume of organic extraction solvent, type and volume of disperser solvent, sample pH, ionic strength, extraction time and centrifugation speed were systematically investigated. The final DLLME protocol involved the addition of 750 μL acetonitrile (disperser) and 50 μL chloroform (extraction solvent) into a 5 mL aqueous honey solution followed by centrifugation. The sedimented organic phase (chloroform) were analysed directly by GC-IT/MS or evaporated and reconstituted in acetonitrile prior to the GC-ECD analysis. The analytical performance of the GC-ECD and GC-IT/MS methods was compared and discussed. Under the selected experimental conditions, the enrichment factors varied between of 36 and 114. The limits of detection (LOD) were in the range of 0.02–0.15 μg L⁻¹ (0.4–3 ng g⁻¹) for GC-ECD and 0.01–0.2 μg L⁻¹ (0.2–4 ng g⁻¹) for GC-IT/MS which is adequate to verify compliance of products to legal tolerances. The proposed method was applied to the analysis of the selected organochlorine pesticides residues in various honey samples obtained from Greek region. Mean recoveries were ranged from 75% to 119% while the precision was better than 20% in both methodologies.     

Diffusion kinetic study of cadmium(II) biosorption by Aeromonas caviae

The removal of cadmium from aqueous solution by sorption on Aeromonas caviae particles was investigated in a well‐stirred batch reactor. Equilibrium and kinetic experiments were performed at various initial bulk concentrations, biomass loads and temperatures. Biosorption equilibrium was established in about 1 h and biosorption was well described by the Langmuir and Freundlich biosorption isotherms. The maximum biosorption capacity was found as 155.32 mg Cd(II) g^?1 at 20 °C. The obtained sorption capacity is appreciably high for most experimental conditions; so A caviae may be considered as a suitable biosorbent for the removal of cadmium. Moreover, the sorption rate of cadmium onto A caviae particles was particularly sensitive to initial bulk concentration and solid load. A detailed analysis was conducted, examining several diffusion (external and intraparticle) kinetic models in order to identify a suitable rate expression. The results are discussed and indicate that biosorption of cadmium is a complex process that is described more correctly by more than one model. Copyright © 2004 Society of Chemical Industry     

Photopolymerization of methyl methacrylate and 2-(dimethylamino) ethyl methacrylate induced by diacetoxyiodobenzene in the presence of radical inhibitors

Summary Polyvalent iodine compounds such as diacetoxyiodobenzene, (CH₃COO)₂IC₆H₅ (DAI), and bis(trifluoroacetoxy) iodobenzene, (CF₃COO)₂IC₆H₅ (BTI), are efficient initiators of cationic and radical polymerizations. To confirm the radical mechanism of DAI-induced polymerization of methyl methacrylate (MMA) and 2-(dimethylamino)ethyl methacrylate (DMAEMA), a study has been performed in the presence of the radical inhibitor 2,3,5,6-tetrachloro-p-benzoquinone (TCQ) and its complex with triethylamine (TEA). The polymerization kinetics and the effect of irradiation intensity have been studied.     

Polymers in mixed solvents: linear representation of viscosity data as a function of molecular weight

In this paper the corrected Stockmayer-Fixman-Burchard equation recently proposed¹³ is applied to the case of polymers dissolved in mixed solvents. A linear plot for viscosity over a very broad range of molecular weights is observed. The unperturbed dimensions of polymers obtained in mixed solvents are related to the thermodynamic properties of the solvent mixtures.     

Photopolymerization of 2-(dimethylaminoethyl)methacrylate induced by diacetoxyiodobenzene and bis(trifluoroacetoxy) iodobenzene

Summary The title hypervalent iodine compounds are efficient photoinitiators for the polymerization of 2-(dimethylaminoethyl)methacrylate. The polymer is formed in daylight but faster under UV irradiation, with high conversion; its molecular weight M_n is 9×10⁴ daltons. Copolymerization of this monomer with styrene occurs also under similar conditions at a high rate. A free radical mechanism is suggested for these polymerizations.