Thermodynamic and kinetic factors effecting hydrogen absorption on metal hydrides

The work of Guvendiren et al. on the effects of additives on mechanical milling and hydrogenation of Magnesium Powder which is published in this journal [Guvendiren M, Bayboru E, Ozturk T. International Journal of Hydrogen Energy 2004; 29: 491–496] shows excellent experimental work which agrees with previous published work. However they did not explain the right phenomenon which is undergoing during hydrogen absorption on magnesium hydride's system. In this communication it is the objective to distinguish between thermodynamic and kinetics factor effecting hydrogen absorption. It will be shown that the phase rule of thermodynamics will determine the variation of Pressure–composition isotherms at constant temperature during hydrogen absorption in Magnesium or Titanium. This is because the Pressure–composition isotherms at constant temperature is different for a single-phase (e.g. beta-Titanium) than two phases (e.g. delta and epsilon phases). Thus the data of Guvendiren et al. published in this journal (Fig. 5) can be explained by this effect.     

Alkaline dyeing of polyester and polyester/cotton blend fabrics using sodium edetate

An alkaline dyeing of polyester with an alkali‐stable disperse dye, Dianix® Scarlet AD‐RG, was developed using sodium edetate as an alkaline buffering agent. The results obtained indicate the suitability of using sodium edetate for alkaline dyeing of polyester when compared with the control alkaline dyeing using Dianix AD system. Selected mono and bifunctional reactive dyes were used in combination with the alkali‐stable disperse dye for dyeing of polyester/cotton blend. Different dyeing methods for cotton and polyester/cotton blend fabrics using sodium edetate were evaluated in comparison with their respective control alkaline dyeing methods. The results of using sodium edetate in one‐bath two‐stage and two‐bath dyeing of polyester/cotton blend were comparable with that of the control dyeing method. Particularly, no change in the leveling and fastness properties was evaluated for all samples irrespective of the dyeing method. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Ocular Poloxamer-Based Ciprofloxacin Hydrochloride In Situ Forming Gels

The purpose of this study was to develop poloxamer-based in situ gelling formulations of ciprofloxacin hydrochloride (HCl) aiming at prolonging corneal contact time, controlling drug release, enhancing ocular bioavailability, and increasing patient compliance. The in situ forming gels were prepared using different concentrations of poloxamer 407 (P407) and poloxamer 188 (P188). Mucoadhesives such as hydroxypropylmethyl cellulose (HPMC) or hydroxyethyl cellulose (HEC) were added to the formulations to enhance the gel bioadhesion properties. The prepared formulations were evaluated for their in vitro drug release, sol–gel transition temperature, rheological behavior, and mucoadhesion force. The in vivo antimicrobial efficacy of selected ciprofloxacin HCl in situ gelling formulations was studied on infected rabbit's eyes and compared with that of the marketed conventional eye drops. The gelation temperature of the prepared formulations ranged from 28.00 to 34.03°C. Increasing the concentrations of P407, HPMC, and HEC increased the viscosity and mucoadhesion force of the preparations and decreased the in vitro drug release. Ciprofloxacin HCl in situ forming gel formulae composed of P407/P188/HPMC (18/13/1.5%, wt/wt), and P407/P188/HEC (18/13/0.5%, wt/wt) showed optimum release and mucoadhesion properties and improved ocular bioavailability as evidenced by an enhanced therapeutic response compared with the marketed conventional eye drops.     

Photoelectric Effects in Single Domain BiFeO3 Crystals

Energy harvesting from sunlight is essential in order to save fossil fuels, which are found in limited amount in the earth's crust. Photovoltaic devices converting light into electrical energy are presently made of semiconducting materials, but ferroelectrics are also natural candidates because of their internal built‐in electric field. Although they are clearly uncompetitive for mainstream applications, the possibility to output high photovoltages is making these materials reconsidered for targeted applications. However, their intrinsic properties regarding electronic transport and the origin of their internal field are poorly known. Here, it is demonstrated that under intense illumination and electric field, oxygen vacancies can be controllably generated in BiFeO₃ to dramatically increase the conductance of BiFeO₃ single crystals to a controllable value spanning 6 orders of magnitude while at the same time triggering light sensitivity in the form of photoconductivity, diode, and photovoltaic effects. Properties of the bulk and the Schottky interfaces with gold contacts are disentangled and it is shown that bulk effects are time dependent. The photocurrent has a direction that can be set by an applied field without changing the ferroelectric polarization direction. The self‐doping procedure is found to be essential in both the generation of electron hole pairs and the establishment of the internal field that separates them.     

A LSA Based Image Classification Framework Utilizing Relative Spatial Arrangement

This paper focuses on the problem of automatic image classification （AIC） by proposing a framework based on latent semantic analysis （LSA） and image region pairs. The novel framework employs relative spatial arrangements for region pairs as the primary feature to capture semantics. The significance of this paper is twofold. Firstly, to the best our knowledge, this is the first study of the influence of region pairs as well as their relative spatial information in latent semantic analysis as applied to automatic image classification. Secondly, our proposed method for using the relative spatial information of region pairs show great promise in improving image semantic classi- fication compared with the classical latent semantic analysis method and 2D string representation algorithm.     

Synthesis and antioxidant activities of some novel fluorinated spiro[oxindole-thiazolidine] fused with sulfur and phosphorus heterocycles

Facile routes were achieved for the synthesis of novel fluorinated spiro[oxindole-thiazolidinone] fused with some sulfur and phosphorus heterocycles starting from 5-fluoro-3^′-(4-fluorophenyl)-4^′H-spiro[indole-3,2^′-thiazolidine]-2,4^′(1H)-dione (1) via its reaction with trifluoroacetamide, 2-chloro-6-fluorobenzaldehyde and hydrazine hydrate followed by treatment with some suitable sulfur and phosphorus reagents. The antioxidant activities of the synthesized compounds were also evaluated.     

Modular ion mobility spectrometer for explosives detection using corona ionization

Ion mobility spectrometry (IMS) has become the most widely used technology for trace explosives detection. A key task in designing IMS systems is to balance the explosives detection performance with size, weight, cost, and safety of the instrument. Commercial instruments are, by and large, equipped with radioactive (63)Ni ionization sources which pose inherent problems for transportation, safety, and waste disposal regulation. An alternative to a radioactive source is a corona discharge ionization source, which offers the benefits of simplicity, stability, and sensitivity without the regulatory problems. An IMS system was designed and built based on modeling and simulation with the goal to achieve a lightweight modular design that offered high performance for the detection of trace explosives using a corona ionization source. Modeling and simulations were used to investigate design alternatives and optimize parameters. Simulated spectra were obtained for 2,4,6-trinitrotoluene (TNT) and cyclo-1,3,5-trimethylene-2,4,6-trinitramine (RDX) and showed good agreement with experimentally measured spectra using a corona ionization source. The reduced mobilities for TNT and RDX obtained with corona ionization were 1.53 and 1.46 cm(2)/(V s), respectively, and this agreed well with literature values.     

Enhancing the adsorption affinity of cellulose acetate film toward cationic dye by incorporating Cloisite 30B grafted with polyacrylic acid

Cellulose acetate (CA) is known for its low adsorption affinity toward dyes, hence this study aims to improve its adsorption affinity toward cationic dyes by introducing Cloisite 30B grafted with polyacrylic acid (C30B-g-PAA). C30B-g-PAA was synthesized by grafting polyacrylic acid (PAA) onto Cloisite 30B (C30B) using in-situ reversible addition fragmentation chain transfer (RAFT) polymerization. Different weight ratios of unmodified (raw) and modified (C30B-g-PAA) C30B (0, 25, and 50 wt%) were incorporated into CA matrices to prepare a series of CA nanocomposite films. The results showed that the adsorption affinity of the prepared nanocomposite films increased toward cationic methylene blue (MB) dye with incorporating either unmodified or modified C30B, but a significant improvement was observed with the incorporating C30B-g-PAA with a maximum adsorption capacity of 53 mg/g for a load of 50 wt%. This indicates that the surface modification of C30B with PAA was effective in enhancing the adsorption efficacy of CA. The kinetic and isotherm studies showed that the adsorption behavior of CA nanocomposite film with 50 wt% of C30B-g-PAA followed pseudo-second-order and Langmuir isothermal model. Regeneration study showed good reusability of CA nanocomposite film with 50 wt% of C30B-g-PAA. These results demonstrate that the nanocomposite film with 50 wt% of C30B-g-PAA can be used as a highly efficient, easy to separate, and reusable adsorbent material to remove MB dye from wastewater.     

Vocabulary recommendation approach for forced migrants using informal language learning tools

Universal Access in the Information Society - Learning a new language is a major challenge faced by many forced migrants. Current vocabulary learning curricula are not adapted to the...