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EVOH/clay nanocomposite films were prepared by using four types of surfactants to treat surface of clay because the surfactants were expected to affect the degree of clay dispersion in the EVOH matrix, which would in turn affect the properties of film. The nanocomposite films that contained the single alkyl tail with two repeating units of oxyethylene surfactants or single alkyl tail surfactant showed higher tensile strength, tensile modulus and elongation at break than those with 15 repeating units of oxyethylene surfactants or those with double alkyl tail surfactant. [ABSTRACT FROM AUTHOR]

Abstract: The electrostatic precipitator (ESP) is the most prevalent application for corona as ion source. ESP is widely used in industrial dust collection and home ventilation systems for cleaning gas streams. However, ESP has not been used to remove gas pollutants from a gas stream. Electron attachment is one of the promising techniques for gas purification. Electron attachment reactions occur when low-energy electrons generated in a corona-discharge reactor are captured by electronegative impurities such as acetaldehyde and fine particles to produce negative ions and charged particles. The negative ions and charged particles drift in the electric field to the anode (reactor wall) and are removed by deposition there. Moreover, O−, O radical, ozone, and OH− are also generated when the carrier gas is humid air. These anions and radicals also contribute to the removal efficiency. Though acetaldehyde (CH3CHO) and ammonia (NH3) are emitted at high temperature from a crematory furnace, there is insufficient report on the effect of high temperature and simultaneous removal. The present research experimentally investigates the technical feasibility of using corona discharge reactions to treat high-temperature exhaust gas containing acetaldehyde and ammonia. The simultaneous removal efficiency of these gases from nitrogen and air is obtained experimentally. The experimental results reveal that the presence of oxygen does significantly enhance the overall removal efficiency. Similarly, it is found that the presence of water vapor also enhances the removal efficiency of the target gases from the nitrogen–oxygen mixture. The generation of undesirable byproducts such as NO x is also investigated. The present technique should be applicable to the simultaneous removal of different nanoparticles at high efficiency. [Copyright &y& Elsevier]

Abstract: The electret filter is composed of permanently charged electret fibers highly capable of collecting charged and uncharged nanosize particles. Compared to the ordinary non-electret fiber, the aerosol collection efficiency η of the electret fiber can initially be significantly higher. In our previous study, η of the electret fiber under dust loading is found to be approximated as the sum of the electrical and mechanical collection efficiencies. It is also shown that the former efficiency can be approximated as a logarithmic function of the dust load. Since the expensive electret filter cannot practically be cleaned and re-used, it is crucial to lengthen its service life without compromising its collection efficiency. In the present study, the time-dependent dust-loaded collection efficiencies of four electret filters with the same average packing density of 0.04 but different linear spatial distributions of the packing density along the filter thickness (0.04 throughout, front 0.03–back 0.05, front 0.02–back 0.06, front 0.01–back 0.07) are simulated and compared. The maximum penetrations and clogging points of the four filters are different. At the maximum 4% penetration through filter D (front 0.01–back 0.07) is two times higher than filter A (0.04 throughout), but the dust load at clogging point of filter D is about 4 times higher than filter A. The results show a significant difference in the distributions of the mass deposited particles along the filter thickness as time passes. As a result, it is possible to quadruple the filter service life by packing the filter loosely on the inlet side and progressively more densely towards the outlet side, while maintaining a sufficiently high aerosol collection efficiency at all times. [Copyright &y& Elsevier]

Abstract: Although hydrogen has a great potential as clean energy, safe practical storage of hydrogen for applications such as fuel cells has been a major challenge. NaAlH4 is one of the metal hydrides, which are candidates for hydrogen storage in vehicles. However, the rather slow absorption/desorption kinetics is still a significant drawback. To alleviate this problem, purified NaAlH4 was ground with TiCl3, ZrCl4, or HfCl4. Desorption kinetics and capacities were observed under TPD-like operation. Absorption efficiency was determined by raising the temperature up to 125°C. Of the three doped metals investigated for the positive effect on facilitating NaAlH4 decomposition, TiCl3 assists the best on the first reaction while ZrCl4 and HfCl4 do for the second one. Despite the kinetics enhancement directly involves with the ZrCl4 amount, there is a threshold of ZrCl4-content which affects. 6% ZrCl4 is considered as an appropriate amount to improve the hydrogen release because it simultaneously decreases the desorption temperature and gives the outstanding rate. In hydrogen desorption, ZrCl4 provides the most amount of released hydrogen, but for hydrogen absorption TiCl3-doped NaAlH4 possesses the highest capacity. It is believed that the metal size is one of the key factors resulting in such the behavior. [Copyright &y& Elsevier]

Abstract: ZnS nanoparticles with different morphology; spherical, ellipsoidal particles'' nanotubes and nanorods, could be successfully synthesized from quaternary W/O microemulsion system. The morphology of the final products could be clearly confirmed by the scanning electron microscopy (SEM) and the transmission electron microscopy (TEM). The effect of cosurfactant on size and morphology of the obtained products have been explored in this work. The key controlling parameters such as the molar ratio of water to surfactant (w o) and the reactant concentration, which affect the product characteristics, have also been investigated. [Copyright &y& Elsevier]