Deformation and strength of cracked member under bending moment and axial force

This paper presents the analysis of the deformation and the strength of a cracked body, emphasizing a superimposed effect of multiple toads on elastic and plastic deformation of an edge-cracked beam or column under two kinds of loads, bending and axial toads. The analysis has been done about the effect of axial force on the elastic angular deformation, including the effect of half-closure of crack, and also on the angular deformation of a cracked plastic hinge. Finally as a practically important example, the above analyses are applied to the problem of the deformation and the load carrying capacity of the cracked column under an eccentric axial force.     

Stress transmission in silica particulate epoxy composite by X-ray diffraction

Stress on particles in silica particulate epoxy composite under constant load was investigated by X-ray diffraction. Microdeformation of the crystal lattice of silica could be detected as a shift of the X-ray diffraction peak induced by the applied stress. When a tensile stress was applied to the particulate composite, incorporated particles were found to be subjected to a stress several times larger than the applied stress. The stress concentration onto particles in particulate composite material, which was considered to result in a mechanical reinforcement of the composite, depends on the volume fraction and size of particles. Quantitative relationships between the stress concentration coefficient, particle diameters and the increment of macroscopic Young's modulus with the incorporation of filler were stated.     

Preparing activated carbon from various nutshells by chemical activation with K2CO3

We have prepared activated carbons by chemical activation with K₂CO₃ from five kinds of nutshells: almond shell (AM), coconut shell (CN), oil palm shell (OP), pistachio shell (PT) and walnut shell (WN). When prepared at 1073 K, the activated carbons from all the nutshells had the maximum specific surface areas. According to the maximum values of specific surface areas, the activated carbons prepared were classified into two groups: Group-L and Group-S; the former group included activated carbons with high specific surface area and the latter included those with lower specific surface area, respectively. It was found that K₂CO₃ effectively worked as an activation reagent, but differently in the temperature ranges below 800 and above 900 K. Due to impregnation, cellulose and hemi-cellulose were modified by K₂CO₃ and accordingly the weight loss behaviors of the nutshells were changed in the temperature range below 800 K. In the temperature range above 900 K, carbon in the chars was removed as CO gas by the reduction of K₂CO₃ to increase the specific surface area and the pore volume. It was deduced that the difference between the specific surface areas of Group-L and those of Group-S correspond to the difference between weight loss behaviors in the temperature range above 900 K.     

Heat and mass transfer characteristics in a gas-slurry-solid fluidized bed

The gas-slurry-solid fluidized bed is a unique operation where the upward flow of a liquid-solid suspension contacts with the concurrent up-flow of a gas, supporting a bed of coarser particles in a fluidized state. In the present study we measured the gas holdup, the coarse particle holdup, the cylinder-to-slurry heat transfer coefficient, and the cylinder-to-liquid mass transfer coefficient at controlled slurry concentrations. The slurry particles were sieved glass beads of 0.1 mm average diameter and their volumetric fraction was varied at 0, 0.01, 0.05 or 0.1. The slurry and the gas velocities were varied up to about 12 and 15 cm/s, respectively. The coarse particles fluidized were sieved glass beads of average diameters of 3.6 and 5.2 mm. The individual phase-holdup values were measured and served for use in correlating the heat and mass transfer coefficients. The heat and mass transfer coefficients in the slurry flow, gas-slurry transport bed, slurry-solid fluidized bed and gas-slurry-solid fluidized bed operations can be correlated well by dimensionless equations of a unified formula in terms of the Nusselt (Sherwood) number, the Prandtl (Schmidt) number and the specific power group including the energy dissipation rate per unit mass of slurry, with different numerical constants and exponent values, respectively, to the heat and mass transfer coefficients. The presence of an analogy between the heat and mass transfer from the vertically immersed cylinder in these slurry flow, gas-slurry transport bed and gas-slurry-solid fluidized bed systems is suggested.     

A complexity measure of task content in information‐input tasks

This article presents a measure of the task complexity a human operator faces while inputting information. The measure, called task‐content complexity (TCC), depends only on the complexity of the task content. A human‐computer information‐transmission model is proposed to clarify task complexity. It is shown that the model has three hierarchical levels of task complexities: the computer device (hardware), the computer software, and the task content. The model provides a definition of task content and the concept of the TCC measure. It is theoretically proven that the TCC measure is related to the task content, and is independent of the computer system used. Experiments based on graphical information‐input tasks confirm that the TCC measures of the same task using two different computer systems are almost equal. They also confirm the strong relationship between the TCC measure and the cognitive complexity of the task the operator performs. The TCC measure will be very useful in the design of computer tasks and in the evaluation and the usability rating of computer systems.     

Propagation of zero sound in superfluid3He-B under magnetic field

We present a theory of zero sound propagation in super fluid³He-B with an order parameter strongly distorted by magnetic field. A general formula of the dispersion relation for arbitrary magnetic field in the collisionless regime is derived within the weak coupling theory and under the assumption of particle-hole symmetry. The Landau parameters are taken into account up toF ₂ ^s andF ₀ ^a . Numerical results for the sound velocity and absorption spectrum are presented. We show that the collective modeJ = 1,J _z = 0 yields a sizable peak in the sound absorption spectrum under weak but finite magnetic field. The quasi-particle excitations under magnetic field also exhibit cusp-like fine structures in the absorption spectrum. We show that the anomalies discovered by Ling et al. and Sounders et al. near the pair breaking edge in theq H geometry consist of theJ = 1,J _z = 0 collective mode and the pair breaking cusps in theJ _z = 0, ±2 channels.     

Effectiveness verification of the hybrid free‐fall test

Free‐fall tests are generally conducted as the last verification step in the cushioning package design process. However, in practice, design requirements are often not met in a single pass of verification testing and two or three repetitions of the ‘design and test’ steps are typically required, necessitating significant amounts of labour and material resources. Therefore, if the product is a prototype or an expensive product, repeated testing is difficult due to the limited quantity or high cost of samples. For such cases, a new method called the ‘hybrid free‐fall test’ is proposed for preventing damage to a tested product. Using this method, the peak shock acceleration occurring during a target (high) free‐fall height test can be predicted using the data from a safety free‐fall height test. The packaged product is usually conceptually modelled to assist in packaging research, and so far, several physical models have been proposed. In this study, we review one such model, the friction‐viscous damping model, and propose a new prediction method for the hybrid free‐fall test in which a reconsidered friction‐viscous damping model is applied. Furthermore, we used expanded polyethylene and structured corrugated sleeve cushioning materials for verification and considered an effective physical model for each cushioning material.     

Thermal conductivity and electrical resistivity of the T′ phase and the T phase in 2-1-4 oxide superconductors

The temperature dependences of the thermal conductivity,(T), and the electrical resistivity,(T), of sintered samples of Nd_1.85Ce_0.15CuO_4–y (NCCO) and Pr_1.85Ce_0.15CuO_4–y (PCCO) with the T phase, and La_1.85Sr_0.15CuO_4–y (LSCO) and La_1.935Ca_0.065CuO_4–y (LCCO) with the T phase, have been measured. The superconducting transition temperatureT _con , of NCCO, PCCO, LSCO, and LCCO were 26.4, 23.0, 37.1, and 8.8 K, respectively. The enhancement of(T) below justT _con such as seen in 1-2-3 oxide superconductors was not clearly observed.(T) for the samples of NCCO and PCCO showed a pronounced maximum such as that of sapphire crystal around 30 and 40 K, respectively. For these samples of NCCO and PCCO, it has been shown that the analysis based on the various phonon scattering mechanisms is in good agreement with our experiment.     

Application of Macromonomers for Pressure Sensitive Adhesives II. Phase Separation and Adhesive Properties

Pressure sensitive adhesives (PSA) were prepared by copolymerization of butyl acrylate, methyl methacrylate and styrene macromer and the effects of macromer on the adhesive properties and phase separated structures were investigated. The results are as follows:

(1) The cohesion of the PSA increased as the quantity of the styrene macromer increased.

(2) The reason why the cohesion of the PSA increased seemed to be that the polystyrene phase, as the graft chain, was separated from the polybutyl acrylate phase as matrix.

(3) When styrene was used instead of styrene macromer, there were not these effects on the adhesive properties.     

Sugar-dependent solubility and fluorescence property of copolymers consisting of phenylboronic acid and 2-hydroxyethyl methacrylate moieties

Copolymers consisting of N-3-acrylamidophenylboronic acid (APBA) and 2-hydroxyethyl methacrylate moieties (HEMA) were synthesized and their solubility and fluorescence properties were evaluated in the presence of sugar. The APBA–HEMA copolymer composed of 25 mol% of APBA moiety was found to be poorly soluble in water at pH 7.4. However, the water solubility of APBA–HEMA was improved in the presence of fructose in solution. The solubility of APBA–HEMA was influenced by fructose in a concentration-dependent manner, due to the formation of boronate ester of APBA moiety with fructose added. In addition, APBA–HEMA was modified with fluorescein isothiocyanate (FITC) for the fluorometric detection of sugars. The fluorescence intensity of FITC-modified APBA–HEMA was dependent on the type and concentration of sugars in solution. The fluorescence intensity of FITC-modified APBA–HEMA was highly enhanced by the addition of fructose, while the fluorescent response was negligibly small when other sugars were added. Thus, usefulness of FITC-modified APBA–HEMA for the selective determination of fructose was demonstrated.