Static and seismic studies on steel/concrete hybrid towers for multi-span cable-stayed bridges

A new type of hybrid high tower is proposed and applied to a multi-span cable-stayed bridge. This is basically a sandwich type structure and consists of a steel double box section filled with concrete. The filled concrete increases its strength due to the confined effect and the steel plates increase the resistance against local buckling because the deformation is restricted by the filled concrete. Therefore, this hybrid tower is expected to have high bending and compressive strength, and also a good ductile property. First, static analysis is conducted for different live load intensity and distribution because the multi-span cable-stayed bridge is a new structure and its static behavior is not fully understood. The live loads distributed in alternate spans give larger bending moment of the towers than the live loads distributed in full spans. Towers with three different heights are also studied, showing that the higher tower produces smaller displacements and bending moments. Safety of the tower is checked by the limit states design method. Serviceability is not a major problem for the hybrid tower. Second, seismic analysis is carried out for a multi-span cable-stayed bridge subjected to the medium and ultra-strong seismic waves specified in Japanese Seismic Code for Highway Bridges. Three support conditions of the girder at the tower cross beams are compared: movable, connection with linear springs and bi-linear springs. Bi-linear springs are very effective in reducing the dynamic displacements and bending moments of the towers. Restorability of the composite tower is checked when an ultra-strong seismic wave hits the model bridge. This study shows that a new steel/concrete hybrid tower is feasible for multi-span cable-stayed bridges and most effective for seismic forces when the girder is connected with bi-linear springs.     

On-chip microfluidic transport and mixing using electrowetting and incorporation of sensing functions

An integrated system was developed that performs microfluidic transport, mixing, and sensing on a single chip. The operation principle for the microfluidic transport was based on electrowetting. A solution to be transported was confined in a space between a row of gold working electrodes and a protruding poly(dimethylsiloxane) (PDMS) structure. When a negative potential was applied to one of the gold working electrodes, it became hydrophilic, and the solution was transported through the flow channel. The solution could be transported in any desired direction in a network of flow channels by switching on necessary electrodes one by one. Furthermore, two solutions transported through two flow channels could be mixed using a mixing electrode based on the same principle. To demonstrate the applicability of a lab-on-a-chip, an air gap ammonia electrode was integrated by taking advantage of the open structure of the flow channel. Gaseous ammonia that was produced after pH adjustment and diffused through an air gap caused a pH change in the electrolyte layer, which was measured with an iridium oxide pH indicator electrode. The 90% response time was less than 1 min for the millimolar order of ammonia. The calibration curve was linear down to 10 microM. The ammonia-sensing system was also applied to construct biosensing systems for urea and creatinine. A linear relationship was observed between the potential and the logarithm of the concentration of the analytes down to 50 microM for both urea and creatinine. The developed microfluidic system can be a basic building block for future systems.     

An Epidemiological Study on Mortality Rates of Various Cancer Sites During 1958 to 1971 By Means of Factor Analysis

Behaviormetrika - In order to analyze the pattern of the geographical and age distributions of the cancer death, the correlation coefficients between any pairs of cancer mortality rates of each...     

Studies on dry spinning. II. Numerical solutions for some polymer–solvent systems based on the assumption that drying is controlled by boundary-layer mass transfer

Numerical solutions of the fundamental equations for dry spinning are obtained by assuming that the rate of the drying of solvent is controlled by the transfer of the solvent vapor at the boundary layer formed outside the filament surface. The polymer–solvent systems for the calculation cover acetate–acetone, poly(vinyl alcohol)–water, polyacrylonitrile–dimethylformamide, and polyurethane–dimethylformamide systems. Quantities necessary for the calculation are summarized. They are material properties (vapor pressures of the solvents, viscosities of the polymer and solvent systems, and so forth) and heat- and mass-transfer coefficients. Mass-transfer coefficients for acetone and dimethylformamide are evaluated by measuring the ratio of heat-transfer coefficients to mass-transfer coefficient based on the method of measuring wet- and dry-bulb temperatures. The variation of the phenomenologic quantities such as solvent content, cross-sectional area, and temperature of the filament along the spinning path is shown in Figure 4.     

Porous alumina ceramics for slip casting molds

Although a slip cast process using a gypsum mold enables large and complicated dense green body to be made, the green body is contaminated with calcium and sulfur impurities from the gypsum mold. In the case of a resin mold, external pressure must be applied due to its poor water wettability. Porous alumina ceramics are used as a mold material for the first time to overcome these problems. The porous alumina ceramics show higher water wettability than gypsum or resin. The porous alumina molds have submicron pores, and provide larger penetration pressure and higher casting rate than gypsum molds.     

Gas chromatographic separation of cholesteryl esters of fatty acids of different degrees of unsaturation

Cholesteryl esters prepared from the fatty acid methyl esters of linseed oil, pig liver lipids, and Japanese anchovy oil have been separated on the basis of their chain lengths and number of double bonds by gas lipid chromatography on a cyanosiloxane SILAR 10C column. The equivalent chain lengths of cholesteryl esters having acyl groups with 14–22 carbons and 0–6 double bonds are presented. A significant influence of the column temperature on the equivalent chain lengths of the polyenoic fatty acid cholesteryl esters has been found. Separation of the cholestanyl and epicholestanyl esters of linseed oil fatty acids, respectively, under the same conditions is also described.     

Development of novel film using paramylon prepared from Euglena gracilis

A novel film was developed using paramylon from Euglena gracilis and its physical properties were investigated. Formic acid was suitable for the preparation of a solution of paramylon, and a transparent even yellow film was obtained by casting the solution on a glass plate and drying the cast film in air without using coagulation bath. However, the spinability of a paramylon solution was fairly low. The spinability was a little enhanced by blending polyvinyl alcohol (PVA) up to 70%. The paramylon/PVA blend fibers were produced through wet spinning using coagulation bath of conc. Na₂SO₄ at a room temperature. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 3495–3497, 2006     

CO2 Decomposition by Oxide Ceramics Intercalated in Layered Compound

Iron oxide polymers intercalated and/or loaded within täniolite have been studied as a CO₂ decomposition medium. Fe²⁺ was exchanged for Li⁺ in täniolite, oxidized by air-bubbling at 60°–70°C. The basic d -spacing (13.75 Å in the Li⁺ form) was expanded to give 14.86 Å in the Fe²⁺ form. Oxidation by air in the form of suspension gave a 15.3-Å phase, which was ascribed to formation of magnetite within the interlayer. The interlayer distance of the intercalated phase remained the same upon heating at 300°C. The magnetite–intercalated täniolite was heated to activate in a H₂ and/or H₂O steam. CO₂ decomposition reactivity at 300°C has been evidenced by evolution of CO gas. The high reactivity for CO₂ decomposition is ascribed to the highly dispersed iron oxide ceramics within the interlayer of täniolite Li[(Mg₂Li)(Si₄O₁₀)]F₂ n H₂O.