The production and characterization of poly(lactic acid) fibers dyeable with anionic dyes using octaammonium polyhedral oligomeric silsesquioxane nanoparticle

In this study, acid dyeable poly(lactic acid) (PLA) fiber was produced with the addition of octaammonium polyhedral oligomeric silsesquioxane (OA-POSS) nanoparticle during the melt spinning. The tensile, thermal and morphological properties of the fiber samples were characterized by tensile testing, differential scanning calorimetry, scanning electron microscopy and transmission electron microscopy. Two different anionic dyes, a disulphonated 1:2 premetallised acid dye and monosulphonated non-metallised, were used. The effects of dyeing conditions including dyeing temperature and time, OA-POSS concentration, anionic dye types and concentrations were investigated on the dyeability properties of the PLA fiber samples. It was concluded that the percent crystallinity and the tensile strength of pure PLA fiber decreased as the added amount of OA-POSS increased. According to the dyeing results, the addition of OA-POSS greatly improved the dyeability of the PLA fiber with anionic dyes by introducing ion–ion interaction between the terminal ammonium groups of POSS nanoparticle and the sulphonyl groups of dye molecules.     

Effect of phosphoric acid and acetic acid addition on the hydrogen evolution using Ni based catalyst prepared in ethanol,methanol, and water solvents

Ni-based catalysts were synthesized in water, methanol and ethanol solvents by chemical reduction with sodium borohydride (NaBH₄). The obtained catalyst for the first time was used to catalyze the NaBH₄ hydrolysis reaction with phosphoric acid and acetic acid including different concentrations. The maximum hydrogen production rates obtained in the hydrolysis reaction including 0.5 M phosphoric acid and 0.1 M acetic acid of the Ni-based catalyst prepared in ethanol solvent were 5214 and 3650 ml g^?1 min^?1, respectively.     

浅析电子商务促进区域一体化发展

随着2008年12月提出《珠江三角洲地区改革发展规划纲要》的提出,小珠三角再次成为世界焦点,其中深莞惠区域合作也被世人关注。但是区域合作知易行难,如何解决地方保护主义、同构严重等问题,本文认为,电子商务是一个可行方案并作出证明。     

A Current-Mode Logic for Low-Voltage, High-Speed Mixed-Mode VLSI Circuits

A wired-AND current-mode logic (WCML) circuit is designed for high performance mixed analog and digital system designs on a common silicon substrate, using standard CMOS process. Current is used for digital information carrier in order to be able to reduce supply voltage, power consumption, digital switching noise and to increase operating frequency. The WCML circuit uses current-steering technique. It is composed of a simple current mirror with a current injector. Wired-AND connections cause the logic circuit to operate as a NAND logic gate which provides to implement any boolean function. High-speed is achieved by varying the injection current level even at low-voltage supply (<1.5 V) with low-power consumption.     

Fast and effective hydrogen production from ethanolysis and hydrolysis reactions of potassium borohydride using phosphoric acid

The hydrogen production from potassium borohydride (KBH₄) with the ethanolysis and hydrolysis reactions using the phosphoric acid as a catalyst is performed for the first time. KBH₄ concentration, phosphoric acid concentration and temperature effects were investigated for the optimum hydrogen production from ethanolysis and hydrolysis reactions of KBH₄. The maximum hydrogen production rates in the ethanolysis and hydrolysis reactions with 1 M phosphoric acid are 6423 and 4296 ml min^?1g^?1, respectively. At the same time, the ethanolysis and hydrolysis reactions with the 1 M acid concentration were completed within 7 and 9 s, respectively. The total conversions obtained for the volume ratio of KBH₄/acid of (1:1) were 100%. The power law kinetic model is performed for the kinetic studies. The activation energies for the ethanolysis and hydrolysis reactions of KBH₄ using phosphoric acid are found as 2.98 and 2.60 kJ mol^?1.     

Improving the dyeability of poly (lactic acid) fiber using octa (aminophenyl) POSS nanoparticle during melt spinning

Disperse dye structure affects the dyeability of poly (lactic acid) (PLA) fiber due to the low dyeing temperature and the short dyeing time. Thus, the dye uptake value of PLA fiber is low for some disperse dyes and needs to be improved. In this study, the dyeability of PLA fiber is improved with the addition of synthesized octa (aminophenyl) polyhedral oligomeric silsesquioxane (OAP-POSS) nanoparticle during the melt spinning process. The effects of dyeing conditions including dyeing temperature and time, OAP-POSS concentration, disperse dye types, and concentrations are investigated on the dyeability properties of PLA fiber samples. The tensile, thermal, and morphological properties of the fiber samples are also characterized by tensile testing, differential scanning calorimetry, scanning electron microscopy, and transmission electron microscopy. It is concluded that the percent crystallinity and the tensile strength of pure PLA fiber decrease as the added amount of OAP-POSS increases. According to the dyeing results, OAP-POSS, which behaves as a good sorbent for the disperse dyes used in this study, greatly improves the dyeability of PLA fiber, especially for disperse dyes with low dye uptake values.     

Microwave Drying Kinetics of a Thin-Layer Liquorice Root

Liquorice root (LR) (Glycyrrize glabra) is known as a sweetener and medicine plant. Drying kinetics of LR with initial moisture content of 49.5% (wet basis (w.b)) were experimentally investigated in a microwave drying system. The drying experiments were carried out at different drying temperatures (40, 45, 50, and 55°C) and microwave power levels (250, 500 and 750 W). Several models from literature were selected to fit the experimental data. The fit quality of models was evaluated using the coefficient of determination (R²), sum square error (SSE), and root mean square error (RMSE). A new model has been proposed for LR drying in the microwave drying. This new model best describes the experimental data for LRs. The activation energy was calculated to be 46.807 kJ/mol and effective diffusivity ranged from 2.9 × 10^?9 to 5.41 × 10^?9 m²/s, depending on drying temperatures at constant microwave power level.     

Morphological,rheological and thermal studies in melt processed compatibilized PA6/ABS/clay nanocomposites

Multicomponent compatibilized blends of polyamide 6 (PA6) and styrene-butadiene-acrylonitrile (ABS) with co-continuous morphology are among commercial alloys with an interesting combination of properties. To further enhance the properties different amounts of nanoclay were incorporated into these blends through a one step melt mixing process. The effect of nanoclay addition on rheological, thermal stability, crystallization and morphological properties of the nanocomposites were investigated and compared with those of the neat blends. The nanoscale dispersion of the clay layers in the blends were confirmed through X-ray diffraction and transmission electron microscopy methods. Rheological investigation indicated an increased viscosity and melt elasticity for the nanocomposite systems. The viscosity of nanocomposites followed a shear thinning flow behavior and decreased with increasing shear rates. The changes in the rheological properties were accompanied by refinement of the co-continuous morphology. For thermal degradation under N₂ atmosphere, the onset and maximum of degradation temperatures for the nanocomposites were as high as the neat blends, while significant improvement in thermal stability (about 60 °C by 3 wt% clay addition) was observed in the air environment. In addition agglomerated clay particles did not significantly affect thermal stability of the polymer matrix. Non-isothermal crystallization results indicated that the clay layers had a retarding effect on the crystal growth rate and facilitated the formation of α crystalline form. In addition no nucleation effect was observed during the crystallization process due to incorporation of nanoclay into the blends.