A novel anionic surfactant templating route for synthesizing mesoporous silica with unique structure

Anionic surfactants are used in greater volume than any other surfactants because of their highly potent detergency and low cost of manufacture. However, they have not been used as templates for synthesizing mesoporous silica. Here we show a templating route for preparing mesoporous silicas based on self-assembly of anionic surfactants and inorganic precursors. We use aminosilane or quaternized aminosilane as co-structure-directing agent (CSDA), which is different from previous pathways. The alkoxysilane site of CSDA is co-condensed with inorganic precursors; the ammonium site of CSDA, attached to silicon atoms incorporated into the wall, electrostatically interacts with the anionic surfactants to produce well-ordered anionic-surfactant-templated mesoporous silicas (AMS). These have new structures with periodic modulations as well as two-dimensional hexagonal and lamellar phases. The periodic modulations may be caused by the coexistence of micelles that differ in size or curvature, possibly owing to local chirality. These mesoporous silicas provide a new family of mesoporous materials as well as shedding light on the structural behaviour of anionic surfactants.     

Fabrication of silicon nitride nanoceramics—Powder preparation and sintering: A review

Fine-grained silicon nitride ceramics were investigated mainly for their high-strain-rate plasticity. The preparation and densification of fine silicon nitride powder were reviewed. Commercial sub-micrometer powder was used as raw powder in the “as-received” state and then used after being ground and undergoing classification operation. Chemical vapor deposition and plasma processes were used for fabricating nanopowder because a further reduction in grain size caused by grinding had limitations. More recently, nanopowder has also been obtained by high-energy milling. This process in principle is the same as conventional planetary milling. For densification, primarily hot pressing was performed, although a similar process known as spark plasma sintering (SPS) has also recently been used. One of the advantages of SPS is its high heating rate. The high heating rate is advantageous because it reduces sintering time, achieving densification without grain growth. We prepared silicon nitride nanopowder by high-energy milling and then obtained nanoceramics by densifying the nanopowder by SPS.     

An energy trading system with consideration of CO2 emissions

Abatement of CO₂ emission is one of the most important issues in the 21st century regarding preservation of the earth environment. This paper addresses a utility operations planning problem for distributed energy management systems (DEMSs), where we are to obtain optimal plans that minimize both costs and CO₂ emissions. A DEMS consists of multiple entities that seek their own economic profits. In this paper, we give a mathematical formulation of the utility operations planning problem for each entity, and propose an energy trading market, which utlizes a multi‐attribute auction protocol in order to deal with both a price and a CO₂ emission rate. Experimental results show that collaboration among entities through the market provides a more profitable plan for each entity and abatement of CO₂ emission is also achieved. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 162(4): 54–63, 2008; Published online in Wiley InterScience ( www.interscience.wiley. com ). DOI 10.1002/eej.20418     

Osteoinduction by Functionally Graded Apatites of Bovine Origin Loaded with Bone Morphogenetic Protein-2

Bioresorbable and functionally graded apatites (fg-HAp) ceramics, which are characterized by gradations in crystallinity and the grain size of hydroxyapatite (HAp:Ca₁₀(PO₄)₆(OH)₂), were designed using bovine bone by the calcination and partial dissolution–precipitation method. The fg-HAp ceramics had macropores of 100–600 μm originated from spongy bone, and micropores of 10–160 nm. Fg-HAp ceramics loaded with recombinant human bone morphogenetic protein-2 (rhBMP-2/fg-HAp) were implanted into the subcutaneous tissue of rats. Eight weeks after the implantation, the surface and bulk degradations of the fg-HAp-containing body fluid occured, and small pieces of fg-HAp were incorporated into the induced bone and fatty marrow, suggesting that osteoinduction occurred in conjunction with bone remodeling. The rhBMP-2/fg-HAp ceramics developed could become a resorbable biomimetic material with fast bioresorption and osteoinduction characteristics.     

Comparison between Y-doped ceria and Ho-doped ceria: Electrical conduction and microstructures

The electrical conduction and microstructure in Y-doped ceria and Ho-doped ceria were investigated. Visible differences between the two doped ceria were observed. The plots of conductivity of Y-doped ceria are well fit to the Arrhenius behavior, while curvature and kinks were observed on the plots of Ho-doped ceria. Such deviation from the Arrhenius behavior could be related to the existence of precipitates in Ho-doped ceria. It indicates that the electrolytic conductivity of doped ceria could be significantly influenced by microstructure features.     

Stress intensity factor error index for finite element analysis with singular elements

An error index for the stress intensity factor (SIF) obtained from the finite element analysis results using singular elements is proposed. The index was developed by considering the facts that the analytical function shape of the crack tip displacement is known and that the SIF can be evaluated from the displacements only. The advantage of the error index is that it has the dimension of the SIF and converges to zero when the actual error of the SIF by displacement correlation technique converges to zero. Numerical examples for some typical crack problems, including a mixed mode crack, whose analytical solutions are known, indicated the validity of the index. The degree of actual SIF error seems to be approximated by the value of the proposed index.     

Three-Dimensional Stress Analysis of Adhesive Butt Joints of Solid Cylinders Subjected to External Tensile Loads

This paper deals with a three-dimensional stress analysis of adhesive butt joints of similar solid cylinders subjected to external tensile loads. Similar adherends and an adhesive bond are replaced with finite solid cylinders in the analysis. Stress distributions on adhesive joints are analyzed strictly by using the three-dimensional theory of elasticity. The effects of stiffness, thickness and Poisson's ratio of the adhesive bonds and of external load distribution on the normal and the shear stress distributions are shown by numerical calculations. In addition, the analytical result is compared with the result obtained by F.E.M. It is seen that they are in fairly good agreement.     

Present status of the High Temperature Engineering Test Reactor (HTTR)

In Japan, the research and development on the High Temperature Gas-cooled Reactors (HTGRs) had been carried out for more than fifteen years since 1969 as the multi-purpose Very High Temperature gas-cooled Reactor (VHTR) program for direct utilization of nuclear process heat such as nuclear steel making. Recently, reflecting the change of the social and energy situation and with less incentives for industries to introduce such in the near future, the JAERI changed the program to a more basic ‘HTTR program’ to establish and upgrade the HTGR technology basis.The HTTR is a test reactor with a thermal output of 30 MW and reactor outlet coolant temperature of 950°C, employing a pin-in-block type fuel block, and has the capability to demonstrate nuclear process heat utilization using an intermediate heat exchanger. Since 1986 a detailed design has been made, in which major systems and components are determined in line with the HTTR concept, paying essential considerations into the design for achieving the reactor outlet coolant temperature of 950°C. The safety review of the Government started in February 1989. By request of the Science and Technology Agency the Reactor Safety Research Association reviewed the safety evaluation guideline, general design criteria, design code and design guide for the graphite and the high-temperature structure of the HTTR.The installation permit of the HTTR was issued by the Government in November 1990.     

Effects of hydroperoxide in breads on IgE antibody responses

The effect of hydroperoxide in breads on antigen-antibody reaction against IgE was examined. We compared the antigen-antibody reaction against IgE between dough including hydroperoxide and that not including hydroperoxide. Crude proteins extracted from the dough including hydroperoxide showed weak antigen-antibody reaction on allergic tests such as ring precipitin test with human-specific IgE, and the IgE binding activity on ELISA. In contrast, the dough without hydroperoxide showed antigen-antibody reaction. The crude proteins extracted from the dough with hydroperoxide or without hydroperoxide were applied by affinity chromatography of trypsin-immobilized chitin. Then proteins having affinity were recovered. The recovered proteins were separated by SDS-PAGE. Each protein was examined for the IgE binding activity on ELISA. The IgE binding activity of baked bread was studied as well. Crude proteins of baked bread made from dough including hydroperoxide showed weaker IgE binding activity on ELISA than proteins of baked bread made from dough without hydroperoxide. Those results suggested that addition of hydroperoxide into dough affects on antigen activation.