Preparation of porous poly(l-lactic acid)/tobermorite composite membranes via electrospinning and heat treatment

A novel poly(l-lactic acid) (PLLA)/tobermorite composite porous membrane for use as filter materials was synthesized by electrospinning a mixture of tobermorite modified by poly(dialyldimethylammoniumchloride) (PDDA) and PLLA. X-ray diffraction patterns of the sample indicated the existence of tobermorite in the sample. Scanning electron micrographs of the sample showed that the nonwoven membrane consists of a few microscopic fibers despite the existence of tobermorite particles. This was due to repulsive force and surface tension. However, no tobermorite particle was exposed at its fiber surface. Thermal analysis showed PLLA of the sample pyrolyzed with two steps of weight loss (44% at around 170 °C and 34% at around 270 °C). Heat treatment of the sample at 130 and 250 °C led to crystallization of a part of amorphous PLLA in the fiber and elimination of the remaining amorphous PLLA, respectively. After the treatment, the membrane maintained its porous structure and was coated with tobermorite particles at the fiber surface.     

Using Field Measurements to Assess Aging of Self-Cleaning High-Reflectance Paint

Continuous field measurements were used to evaluate the aging of solar reflectance on self-cleaning coatings for roofs in comparison with conventional coatings that have no self-cleaning function. Solar reflectance on self-cleaning coatings decreases by about 6 % per year with annual variations, due to the adhesion of dirt. On the other hand, solar reflectance on conventional coatings greatly decreases, by approximately 18 % within four months of the coating’s application, due to the adhesion of dirt. Then, it gradually recovers at a rate of about 4 % per year, with annual variations, due to degradation of the coating. It is due to degradation of the conventional coating that the difference of solar reflectance between the self-cleaning coating and the conventional coating becomes almost zero in two years. Both the adhesion of dirt and coating degradation by chalking affect the temporal change of solar reflectance with annual variation.     

Joining of Silicon Nitride by Local Heating for Fabrication of Long Ceramic Pipes

This study demonstrated that a long silicon nitride pipe of several meters with adequately strong joints can be fabricated by a local‐heating joining technique. Commercially available silicon nitride ceramic pipes sintered with Y₂O₃ and Al₂O₃ additives were used for parent material, and powder slurry of Si₃N₄‐Y₂O₃‐Al₂O₃‐SiO₂ system was brush‐coated on the rough or uneven end faces of the pipes. Joining was carried out by locally heating the joint region at different temperatures from 1500°C to 1650°C for 1 h with a mechanical pressure of 5 MPa in N₂ flow; using a horizontal electrical furnace specially designed for this experiment. The silicon nitride pipe 3‐m long was successfully fabricated without voids or cracks in the joint region, and the microstructure of the joint region was similar to that of the parent one. The joint strength was examined in flexure using specimens cut from the joined pipes, and those joined at 1600°C and 1650°C indicated the highest strength of about 680 MPa, which was almost the same as that of the parent material. This study also indicated that the slurry brush‐coating technique is advantageous to easily joining ceramic pipes with rough or uneven end faces, which is essentially important for practical use.     

Water Migration Phenomenon Model in Cracked Concrete.?II: Calibration

The material parameters to express the degree of discontinuity of hydraulic gradient in the developed model (Part I) are calibrated based on the sensible analysis of the experimental results, and then the applicability of the calibrated parameters is discussed. As a result, the material parameters are calibrated by the sensible analysis, and then its relevance can be confirmed by another experiment. Moreover, it can be seen that the normalized permeability of concrete as a nonhomogeneous material by the initial permeability (homogeneous material) can be regressed with three straight lines in the crack width axis with the logarithm. Then the intersection point at the crack width axis shows the critical width at which leakage will not occur. The intersection point at the last two straight lines shows the critical Reynolds number at which flow becomes laminar to turbulent according to the experimental result.     

A Framework for Cross-Language Information Access: Application to English and Japanese

Internet search engines allow access to online information from all over the world. However, there is currently a general assumption that users are fluent in the languages of all documentsthat they might search for. This has for historical reasons usually been a choice between English and the locally supported language. Given the rapidly growing size of the Internet, it is likely that future users will need to access information in languages in which they are not fluent or have no knowledge of at all. This papershows how information retrieval and machine translation can becombined in a cross-language information access frameworkto help overcome the language barrier. We presentencouraging preliminary experimental results using English queries toretrieve documents from the standard Japanese language BMIR-J2retrieval test collection. We outline the scope and purpose ofcross-language information access and provide an example applicationto suggest that technology already exists to provide effective andpotentially useful applications.     

Evaluation of electric energy performance by democratic module PV system field test

A systematic investigation has been made on annual accumulated generated PV power from different solar arrays consisting of three kinds of silicon-based solar cells. To clarify seasonal output power variations with temperature in c-Si and a-Si cells might be an important issue for the operations of PV system. It has been shown from the results that electric output power from a-Si array in summer is 20% larger than that from c-Si. On the other hand, in winter, this scene should be reverted. However, output power from c-Si array is only 5% larger than that from a-Si. The analyzed data also shows that annual accumulated electric power generated from a-Si array corresponds to 90% of its nominal efficiency in the year. While in case of c-Si array, this ratio is about 84%.     

Preparation of Highly Crystalline TiO<Subscript>2</Subscript> Nanostructures by Acid-assisted Hydrothermal Treatment of Hexagonal-structured Nanocrystalline Titania/Cetyltrimethyammonium Bromide Nanoskeleton

Highly crystalline TiO₂ nanostructures were prepared through a facile inorganic acid-assisted hydrothermal treatment of hexagonal-structured assemblies of nanocrystalline titiania templated by cetyltrimethylammonium bromide (Hex-ncTiO₂/CTAB Nanoskeleton) as starting materials. All samples were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The influence of hydrochloric acid concentration on the morphology, crystalline and the formation of the nanostructures were investigated. We found that the morphology and crystalline phase strongly depended on the hydrochloric acid concentrations. More importantly, crystalline phase was closely related to the morphology of TiO₂ nanostructure. Nanoparticles were polycrystalline anatase phase, and aligned nanorods were single crystalline rutile phase. Possible formation mechanisms of TiO₂ nanostructures with various crystalline phases and morphologies were proposed.     

Bubble formation in cocurrently upward flowing liquid

The effects of liquid velocity, nozzle diameter, gas chamber volume and gas flow rate on volumes, shapes and growth curves of bubbles formed at a nozzle submerged in a cocurrently upward flowing liquid in a bubble column were experimentally investigated. The bubble volume decreases with increasing liquid flow velocity. The effect of liquid flow velocity on the volume of bubble increases with an increase in the gas flow rate. To simulate bubble formation at a nozzle submerged in cocurrently upward flowing liquid, a revised non-spherical bubble formation model was proposed. Bubble volumes, bubble growth curves and shapes experimentally obtained in this study, as well as in previous experimental studies, are well predicted by the present model.     

Effect of the Mild Temperature and Traditional Treatments on Residual Peroxidase Activity,Color, and Chlorophyll Content on Storage of Mate (Ilex paraguariensis) Tea

The green coloring is the first characteristic in mate tea (chimarrão). Mate producers perform the sapeco process by rapidly passing the leaves through flames. It has been proven that this procedure leads to high energy consumption and also to excessive exposure of the raw material to heat. In this present work, the effect of sapeco on the inactivation of peroxidase, the color, and degradation of the chlorophyll in mate was evaluated by performing the sapeco procedure in a conveyor oven, without any direct contact with the flames. The mate processed in a conveyor oven was compared with mate processed in mate factories. Inactivation of peroxidase showed that sapeco performed in a conveyor oven at 255 ºC for 20 s can replace the traditional process of the industrial sapeco. This time/temperature binomial is significantly important for the green coloring and the minimization of chlorophyll degradation, besides representing a significant reduction in the temperature traditionally applied in the industrial sapeco of mate.     

Kinetic analysis on gaseous and aqueous product formation by mixed anaerobic hydrogen-producing cultures

Anaerobic hydrogen production by mixed cultures is a complex process, and information about its kinetic analysis is sparse. In this study, an integrated approach with the weighted nonlinear least-squares analysis and accelerating genetic algorithm is proposed to evaluate the kinetic parameters of biohydrogen production from a sucrose by mixed anaerobic cultures. The weighted nonlinear least-squares analysis is used to calculate the differences in gaseous and aqueous product concentrations between the predicted and the measured results, while the accelerating genetic algorithm is utilized to optimize the objective function by minimizing the total sum of the squared weighted errors. The kinetic parameters for specific maximum substrate uptake rate, substrate uptake affinity constant, yield coefficient are calculated with this approach, and are validated by the results of the independent experimental results reported in literature. This integrated approach is effective and rapid to estimate the anaerobic hydrogen production kinetics by mixed cultures.