Estimation of the variance of steady vibration responses of structures with random parameters and method to compute the allowable variance of the parameters

When parameters contributed to mass and rigidity of the structures have randomness, the steady vibration responses of the structures have random characteristics.In this paper the method to estimate the variance of the response and to compute the allowable variance are described. In the computation the partial derivative method is used and effectiveness of the method is examined for simple numerical examples.     

Influence of detergent builders on surface properties of sodium dodecyl sulfate solutions under dynamic and static conditions

The effects of various detergent builders on surface properties of sodium dodecyl sulfate (SDS) solutions have been investigated by measuring the equilibrium surface tension and hysteresis curves of surface pressure vs surface area under dynamic conditions. While the adsorbed layer of SDS under static conditions is in the liquid-expanded state, a two-dimensional phase transition of the adsorbed layer from liquid-expanded to condensed-film can be observed on compression at higher rates beyond the saturated adsorption. For the SDS solution containing excess NaCl (1×10⁻¹ M), the adsorbed layer of SDS is already in the condensed state under static condition due to a depression in the dissociation of SDS. It has been found that some polyelectrolytes, as well as conventional ionic builders, contribute to increasing the surface excess concentration of SDS together with promoting micelle formation and also to stabilizing the adsorbed layer of SDS. On the other hand, poly(vinyl alcohol) (PVA) as a nonionic polymer is adsorbed at the air-water interface in preference to SDS. In this case, the hysteresis of the dynamic surface behavior of the mixed solution can be attributed to the structural change of the adsorbed layer of PVA rather than SDS, which is different from the other ionic builders.     

Slip-line fields for steady-state extrusion through frictionless doubly wedge-shaped dies in plane strain

Slip-line field solutions for steady extrusion through doubly wedge-shaped frictionless die are obtained by assuming a quadrilateral rigid region lying adjacent to the smaller angle wedge surface of the die. Several patterns of the slip-line field are presented. The ranges of the extrusion geometries within which those fields are valid are shown.     

Far-infrared spectroscopy by synchrotron radiation at the UVSOR Facility

At the UVSOR Facility, Institute for Molecular Science, the practical use of the synchrotron radiation as a far-infrared light source has started. A spectroscopic system has been constructed at the beam line BL6A1 of UVSOR storage ring, which covers the wavenumber region from 5 to 250 cm^?1. The cross sectional diameter of the light beam at the sample position is as small as 3 mm with the angular divergence of about 100 mrad. The system has been made mainly for the transmission and reflection measurements of small samples with small angular divergence by the use of the high brightness of the synchrotron radiation. Examples of observed transmission and reflectivity spectra are shown.     

Performance of a polymer electrolyte fuel cell for automotive applications

The objectives of this study were to fabricate a self‐humidifying fuel cell stack of 10 cells with 104 cm² cell areas humidified with water recovered at cathodes, and to measure and simulate the performance of the stack. This involves the simulation of a three‐dimensional model of the heat and mass transfer of the water and the gaseous reactants in the fuel cell components with a water‐cooling system. The results of the stack experiments indicated a maximum power of 250 kW at a current density of 0.5 A/cm². The simulation showed good agreement with the actual performance of the stack. The performance of the self‐humidifying stack with a vapor‐permeating membrane is comparable to a conventional stack with external humidifiers, and it appears very effective in simplifying stack systems. The modeling analysis indicated that for the gas flow directions, at anode and cathode, a parallel flow is superior to a cross flow, and that one cooling cell is necessary for two to three generating cells in order to maintain the fuel cell temperature below 100 °C. © 2002 Wiley Periodicals, Inc. Heat Trans Asian Res, 31(6): 421–429, 2002; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/htj.10041     

Generation of Oxygen-Containing Radicals in the Aqueous Media of Mechanical Pulping

Mechanical treatments of veratrylglycerol-β-syringaldehyde ether (M) were conducted with a ceramic ball mill or a vibration ball mill in the presence of water and n-paraffin alcohols which were used as ·OH scavengers. Addition of 1% each of the alcohols to the milling process of Compound (M) greatly decreased the yields of the products, e.g. veratryl alcohol 2, vanillin 3, syringaldehyde 4, 3,5-dimethoxy-p-benzoquinone 5, 3,5-dimethoxy-p-hydroquinone 6 and others. Another addition of n-paraffin alcohols to aqueous media during the millings also significantly reduced the concentration of H₂O₂. When phthalic hydrazide (P) was treated in the mills in the aqueous media, triacetoxyphthalazine (1A), 3-acetoxyphthalic acid (2A) and other products were separated from the acetates of the reaction mixtures. Results mentioned above disclosed the generation of ·O₂H, ·OH, and ·H in the aqueous media during the mechanical treatments.     

Optical tweezers and fluid characteristics of an optical rotator with slopes on the surface upon which light is incident and a cylindrical body

The characteristics of the optical trapping force, optical torque, and viscous drag force for a newly proposed cylindrical optical rotator are analyzed. The optical trapping force and torque are evaluated by use of a ray optics model for both parallel and focused laser beam illumination. The drag force is calculated from computational fluid dynamics to be the sum of the components of both the pressure and the shearing stress on all the surfaces of the rotator. We analyze the rotation rate by balancing the optical torque with the drag force. A cylindrical optical rotator is expected to rotate at a high speed because of its highly efficient generation of optical torque and its small viscous drag force.     

Polymerizabilities of amphiphilic monomers with controlled arrangements in Langmuir-Blodgett films

Polymerization of amphiphilic monomer Langmuir-Blodgett (LB) films, such as long-chain derivatives of -amino acids and diynoic, trienoic and acrylic acids, was studied. Multilayers of these monomers were prepared on CaF₂ or quartz plates by the LB method under various conditions, and polymerization processes were followed by IR and UV spectroscopy. The polycondensation of dioctadecyl- - glutamate proceeded easily in LB films at ordinary temperatures below the melting point without any initiation. All-trans- and 9-cis-9,11,13-octadecatrienoic acids polymerized very rapidly in LB films on UV irradiation. Photopolymerization in LB films of 10,12-tricosadiynoic acid was influenced by the deposition modes and annealing, and that of octadecyl acrylate was accelerated by the addition of the long- chain vinyl ether. In any case, polymerization reactions are markedly enhanced by a well-controlled arrangement of the monomer molecules in the LB films.     

Chain extenders for polyesters. V. Reactivities of hydroxyl-addition-type chain extender; 2,2′-bis(4h-3,1-benzoxazin-4-one)

In our previous study,¹ 2,2′-bis(4H-3,1-benzoxazin-4-one) (BNZ) was found to be most effective among the tested chain extenders in coupling hydroxyl terminals of linear polyesters through addition reaction. Detailed studies on BNZ chemistry have been made using poly(ethylene terephthalate) and poly(butylene terephthalate) as the polyester. It has been observed that use of BNZ, equivalent amount to the hydroxyl terminals of the initial polymer, resulted in the highest molecular weight. In contrast with the case of 2,2′-bis(2-oxazoline), which was found to be the most effective carboxyl-addition type chain extender and a wide range of its excess use was allowed,^2,3 an excessive use of BNZ resulted in lower molecular weight polymer. Thus, when an equivalent amount of BNZ to the hydroxyl terminals was used, the molecular weight of the resulting polymer could be determined by the carboxyl content of the initial polymer, regardless of its initial molecular weight.