Orientated crystallization in drawn thermoplastic polyimide modified by carbon nanofibers

The solid state crystallization in drawn thermoplastic polyimide films is studied as a function of draw ratio (DR) under the effect of vapor grown carbon fiber nanoinclusions. The nucleating effect of the nanoinclusions coupled with the orientation effect of drawing generates a unique orientated layered lamellar structure, characteristic of smectic‐like mesophase. The degree of draw induced orientated crystallization increases with the content of nanoinclusions and with the DR, and is reflected in the mechanical behavior of the film. Generally, the Young's modulus and the yield point of the drawn crystalline films in the drawing direction are significantly higher compared with the noncrystalline counterparts. POLYM. ENG. SCI., 2009. © 2008 Society of Plastics Engineers     

Aggregation of Tetrakis(4-methylpyridyl)porphyrin and tetrakis(4-sulphonatophenyl)porphyrin in water

The homo- and heteroaggregation of two oppositely charged water soluble porphyrins, tetrakis(4-methylpyridyl)porphyrin, TMPyP and tetrakis(4-sulphonatophenyl) porphyrin, TSPP has been studied by means of absorption and fluorescence spectroscopy in phosphate buffered saline. All experimental results on TSPP are consistent with a monomerdimer equilibrium (ΔH = −19.6 and ΔS = 19.3 kJ mole⁻¹). The absorption spectrum of the TSPP dimer was obtained from a global fit of a set of spectra to the monomer dimer model. TMPyP does not aggregate at concentrations up to 10⁻⁴M . Changes in the fluorescence spectrum of TMPyP upon dilution are due to adsorption phenomena. 1:1 heteroagregates of both porphyrins cannot be characterized in water solution due to extreme small solubility. A 2:1 heteroaggregate is detectable in solution. It is proposed to exploit the extreme small solubility of heteroaggregated oppositely charged porphyrins to increase the selective retention of porphyrins provided there is an initial selectivity of ether component.     

Urethrocystometry as a routine method for the objective evaluation of women with urinary incontinence

Over a 2-year period, 401 patients with urinary incontinence were examined at the Women's Clinics in Lund and Malm? and then investigated by urethral pressure profile measurement and simultaneous urethrocystometry. After full investigation the patients could be classified as follows: 214 (53.4%) had genuine stress incontinence, 48 (12.0%) had genuine urge incontinence, 41 (10.2%) had mixed incontinence, 20 (5.0%) had urgency-frequency, 6 (1.5%) had neurogenic incontinence, 9 (2.2%) had incontinence of uncertain aetiology, and 63 (15.7%) of the patients were apparently continent with normal urethral pressure profiles and urethrocystometrograms.     

Demodulation techniques for the amplitude modulated laser imager

A new technique has been found that uses in-phase and quadrature phase (I/Q) demodulation to optimize the images produced with an amplitude-modulated laser imaging system. An I/Q demodulator was used to collect the I/Q components of the received modulation envelope. It was discovered that by adjusting the local oscillator phase and the modulation frequency, the backscatter and target signals can be analyzed separately via the I/Q components. This new approach enhances image contrast beyond what was achieved with a previous design that processed only the composite magnitude information.     

Amplitude-modulated laser imager

Laser systems have been developed to image underwater objects. However, the performance of these systems can be severely degraded in turbid water. We have developed a technique using modulated light to improve underwater detection and imaging. A program, Modulated Vision System (MVS), which is based on a new theoretical approach, has been developed to predict modulated laser imaging performance. Experiments have been conducted in a controlled laboratory environment to test the accuracy of the theory as a function of system and environmental parameters. Results show a strong correlation between experiment and theory and indicate that the MVS program can be used to predict future system performance.     

An overview of web accessibility in Greece: a comparative study 2004–2008

This communication reports on the results of a web accessibility audit of public Web sites in Greece. The audit was conducted in 2008 by the Human Computer Interaction Laboratory of the Institute of Computer Science of FORTH, in its capacity as the Greek National Contact Centre of the European Design for All e-Accessibility Network. In an earlier e-Accessibility study in 2004, that evaluated approximately 250 public and commercial Web sites in Greece, 73% of the sample failed to meet the most basic requirements for web accessibility (). Four years later, in the context of a re-audit, a similar sample was examined for compliance with the same web accessibility standard (WCAG 1.0), as set by the Web Accessibility Initiative of the World Wide Web Consortium. The accessibility checks were conducted during the period from March to September 2008. A comparison of the results indicates that although new web development technologies may have been employed, instead of improving the overall status of e-accessibility, this has resulted in a serious deterioration in overall accessibility levels. Such findings—85% of sites failed to comply with Level A—suggest that Greek Web sites are likely to present even more significant access barriers to people with disability than in the past. As Web Accessibility is poorly understood and, until today, new platforms have failed to deliver products that conform to WCAG, the need emerges for a concrete legislative framework to set accessibility specifications for all public Web sites in Greece.     

Morphology evolution induced by carbon nanotubes on thermal and mechanical characters of semi-crystalline aromatic polyimide

A series of nanocomposites based on a new semi-crystalline polyimide (PI) and multi-walled carbon nanotubes (MWCNTs) were prepared by in situ polymerization. The TEM measurement reveals the improved dispersion of carboxylic acid-functionalized MWCNTs (COOH-MWCNTs) in semi-crystalline PI compared with pristine MWCNTs. The TGA analysis show that the concentration of carboxylic acid groups on the surface of nanotubes is about 4.34 wt%. The FT-IR spectroscopy analysis indicate that the imide rings of the PI interact non-covalently with nanotubes. The Polarized optical microscopy observation reveals significant morphology evolution in semi-crystalline PI induced by MWCNTs. The SEM micrographs suggest the strong interfacial interaction between COOH-MWCNTs and PI main chains, and significant changes in the fracture surfaces morphology. The WAXRD measurements reveal that COOH-MWCNTs promote the semi-crystalline PI crystallinity and structure change. COOH-MWCNTs can more efficiently improve the mechanical and thermal properties of resulting nanocomposites than pristine MWCNTs. COOH-MWCNT/PI nanocomposites show increases of Young’s modulus and yield strength, as high as 20–30 %, without sacrificing the elongation at break at loadings of 0.5 wt% nanotubes. Furthermore, with increasing the loadings of COOH-MWCNTs to 1.0 wt%, Young’s modulus and yield strength decrease due to nanotube aggregation, but elongation at break increase about 46 %. An abrupt increase of elongation at break in pristine MWCNT/PI nanocomposites was also registered at nanotubes loadings increasing from 0.5 to 1 wt%. These results indicate that the properties of semi-crystalline PI nanocomposites reinforced with carbon nanotubes are not only determined by the dispersion of nanotubes in the PI matrix and their interfacial interactions, but also by the crystalline phase morphology evolution in the PI matrix.     

Influence of cobalt ferrite content on the structure and magnetic properties of (CoFe2O4)X (SiO2-PVA)100-X nanocomposites

(CoFe₂O₄)_X(SiO₂-PVA)_100-X (X = 5, 25, 50, 75 and 95%) nanocomposites were prepared via sol-gel route and annealed at 700 and 1100 °C. The influence of CoFe₂O₄ content on the structure, morphology and magnetic properties of nanocomposites was studied. X-ray diffraction patterns, Mössbauer and Fourier transform infrared spectra revealed the formation of CoFe₂O₄ as unique magnetic phase. The crystallinity degree increases with the CoFe₂O₄ content and the annealing temperature. Transmission electron microscopy images revealed the spherical shape of the obtained nanocomposites. Mössbauer spectra exhibit typical magnetic sextets, allowing the calculation of the cations distribution among tetrahedral and octahedral sites and the stoichiometry of CoFe₂O₄. A strong correlation between the particle morphology and the magnetic properties of nanocomposites was found. The highest saturation magnetization was identified for (CoFe₂O₄)₉₅(SiO₂-PVA)₅ nanocomposite.     

Recycling of Water and Valuables in Steel Production

Steel production without water is impossible. Given the increasing water scarcity, SMS group is making great efforts to develop its ecoplants products and processes that are characterized by low energy and water consumption and recycling of valuables. The innovations presented here include process‐integrated solutions like the rotating descaler Piroscale® MAT and the ETL evaporator as well as end‐of‐pipe solutions such as the reclamation of valuables using the Ciroval® process or the recycling of water from cooling circuit blowdown, as implemented in the WEISS project.