Effects of hysteretic model on seismic demands: consideration of near‐fault ground motions

This paper summarizes the results of a study that is to evaluate the structural response attributes of near‐fault ground motion. Ground motion recordings from the Chi‐Chi earthquake are used as inputs to the structural system. An improved nonlinear hysteretic model, based on the experimental study, was used to calculate the response of the single degree‐of‐freedom inelastic system. Comparison of the results of analysis with traditional elastic–perfect plastic mode calculations was made. Discussions on the inelastic design spectrum, particularly the code‐specified base shear coefficients, using the improved nonlinear hysteretic model incorporated with the near‐fault input ground motion are made. Copyright © 2002 John Wiley & Sons, Ltd.     

Synthesis and properties of some novel,soluble and light‐coloured,aromatic poly(amide–imide) copolymers

A new type of tetraimide‐dicarboxylic acid (I) was synthesized starting from the ring‐opening addition of m‐aminobenzoic acid (m‐ABA), 4,4′‐oxydiphthalic anhydride (ODPA) and 4,4′‐methylenedianiline (MDA) at a 2:2:1 molar ratio in N‐methyl‐2‐pyrrolidone (NMP), followed by cyclodehydration to the diacid I. A series of soluble and light‐coloured poly(amide–imide–imide)s (III_a–j) was prepared by triphenyl phosphite‐activated polycondensation from the tetraimide‐diacid I with various aromatic diamines (II_a–j). All films cast from DMAc had cutoff wavelengths shorter than 400 nm (376–393 nm) and had b* values between 20.46 and 40.67; these polymers were much lighter in colour than those of the corresponding trimellitimide series. All polymers were readily soluble in a variety of organic solvents such as NMP, N,N‐dimethylacetamide, dimethyl sulfoxide, and even in the less polar m‐cresol and pyridine. Compared with those of corresponding ODPA–MDA polyimide, the solubilities of poly(amide–imide–imide)s III_a–j were greatly improved. Polymers III_a–j afforded tough, transparent, and flexible films, which had tensile strengths ranging from 82 to 105 MPa, elongations at break from 8 to 14%, and initial moduli from 2.0 to 2.2 GPa. The glass transition temperature of polymers were recorded at 255–288 °C. They had 10% weight loss at a temperature above 540 °C and left more than 60% residue even at 800 °C in nitrogen. © 2002 Society of Chemical Industry     

Ultrasonic characterization of the effect of cold work and grain size in copper and 68:32 brass sheets

The effectiveness of ultrasonic velocity measurements was evaluated as a means for nondestructive characterization of cold-rolled copper and 68:32 brass sheets. An apparatus was designed to generate and receive the zeroth symmetrical mode of ultrasonic Lamb waves in thin copper and brass sheets. The effect of angular variations in propagation direction with respect to the rolling direction on the measured Lamb wave velocities is shown. Interpretation of the variations of ultrasonic Lamb wave velocity were related to deformation mechanisms and texture development in copper and 68:32 brass sheets. Results show that the grain size and cold work influence the velocity as well as the texture of copper and 68:32 brass sheets. Results indicate the possibility of using ultrasonic Lamb wave velocity as a tool to monitor elastic anisotropy.     

Teaching A level physics through microcomputer dynamic modelling: Evaluation of teaching

Abstract  This paper describes an evaluation of teaching A level Physics through dynamic modelling. This teaching was carried out with a group of 12 lower sixth Nuffield A level Physics students and was evaluated with three tests internal to the school and with the external public Nuffield A level Physics (NAP) examination which those students later took. The internal school tests showed that the treatment group performed better than an equivalent non-treatment group in both general ability and in a few particular skills. The public NAP examination showed no superiority of the treatment group, but indicated a significant preference for an optional question that involved mathematical skills, even though none of the treatment group took mathematics at A level. Comments are made about the educational significance of dynamic modelling and about computers in education generally.     

Usage patterns,health, and nutritional status of long-term multiple dietary supplement users: a cross-sectional study

Background  

Dietary supplement use in the United States is prevalent and represents an important source of nutrition. However, little is known about individuals who routinely consume multiple dietary supplements. This study describes the dietary supplement usage patterns, health, and nutritional status of long-term multiple dietary supplement users, and where possible makes comparisons to non-users and multivitamin/mineral supplement users.     

Electroosmotic flow in irregular shape microchannels

The electrokinetic flow through star-point family microchannels is studied. Mathematical solutions using a semi-analytical approach are employed to model the steady, fully developed electroosmotic flow in the closed-end star point family microchannels. The model can be extended to other irregular shape channels. The effects of sharp corners, electrolyte concentration and packed capillary radius, R₀ are analyzed. Comparisons of the flow characteristics and induced pressure gradient inside and outside of the packed capillaries are presented.     

The relationship between attentional blink and psychological refractory period.

This study examined the relationship between attentional blink (AB) and psychological refractory period (PRP) using a conventional AB procedure combined with a requirement of speeded responses to the second target (T2). Experiments 1 and 2 showed that, as with PRP, memory retrieval of targets is not a necessary condition for the occurrence of AB in terms of accuracy and that AB occurred in the speed data. Experiment 3 further indicated that the PRP-like speed data were not due to the first target serving as a warning signal that triggered preparation of responses to T2. Experiment 4 manipulated T2 stimulus intensity to be normal or low. Results showed an underadditive interaction between stimulus intensity and lag position in the speed data, whereas an overadditive interaction was found in the accuracy data, suggesting 2 sources of interference leading to AB: the single-channel bottleneck and resource-limited visual-processing capacity. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Hydrothermal processings to produce magnetic particulates

α-Fe₂O₃, γ-Fe₂O₃ , and α-FeOOH powders were used as starting materials to prepare barium hexaferrite hydrothermally. Since strontium hexaferrite and lanthanum-doped calcium hexaferrite have coercivities similar to that of barium ferrite, the hydrothermal synthesis of strontium hexaferrite and lanthanum-doped calcium hexaferrite were also explored. The reaction products obtained with the various starting materials are described. Electron micrographs showed that α-Fe₂O₃, γ-Fe₂O₃, or α-FeOOH dissolved in the solution first, and then barium hexaferrite nucleated and grew from the solution