The state equation of the mercury porosimetry is formulated on the basis of rigorous thermodynamics. Expression of the state equation is Helmholtz’ free energy and it is formulating the interfacial energy due to adsorbing liquid and vapor phase mercury to the solid surface under increasing pressures. No particular pore geometry and relative arrangement of the injected mercury were assumed. The interfacial energy is based on the standard state of the mercury with free surface, and it changes by forming a new interface with an injection of mercury. As a consequence, a new concept of the effective surface area was proposed. The physical meaning of the effective surface area is the whole interfacial energy corresponding to the void capacity of pore component according to the pressure levels, and is able to predict the adsorption state in clear configuration. The effective surface area of hardened cement paste were evaluated under various water cement ratio

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In-situ stress measurement using the Kaiser effect of AE (Acoustic Emission) was adapted to investigate the underground stress conditions. Most rocks are porous to some degree. If the pores of in-situ rock contain pore water, rocks (in-situ rock mass) are subjected to in-situ stress and furthermore pore water pressure. However the influence of pore water pressure on the Kaiser effect has not been studied. In this study, we performed experiments to clarify the influence of pore water pressure on the Kaiser effect using sandstone. Firstly, uniaxial compressive stress was re-loaded after triaxial compressive pre-loading with several pore water pressures. Secondly, triaxial compressive re-loading was performed under different several pore water pressures after triaxial compressive pre-loading with pore water pressure. Two points having rapidly increasing cumulative AE event count were observed. The two stresses of 1st and 2nd Kaiser effect points were then compared with pre-effective axial stress and pre-differential stress. The estimated stresses were very close to those pre-stresses, and not influenced by pore water pressure in pre-loading and re-loading.

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The applicability of the digital image correlation method (DICM) to the fields of civil engineering and architecture was investigated through analyzing the strain distribution of mortar specimen under uniaxial compression. As a result, it was proved that the strain of mortar specimen under uniaxial compression was well measured by digital image correlation method with the same precision as strain gauges. Digital image correlation method makes it possible to obtain the strain distribution on the surface of an object easily, and can be a powerful tool for the tracking of the local deformation of structures.

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The in-plane and through-thickness (or z-direction) tensile stress-strain properties of two kinds of commercial (or machine-made) paper and paperboard were determined in a compact testing machine equipped with a non-contacting optical extensometer. Copy paper, UKP (unbleached kraft pulp)-sack paper and uncoated 7-layer paperboard were tested at about 23 ±2°C under 55±2 % relative humidity. A dumbbell or dog-bone type specimen specified in the JIS Z 2201 for sheet materials was adopted in the in-plane tensile tests, instead of a constant-width strip specimen specified in the JIS P 8113 or ASTM D828-97. Circular specimens of uncoated paperboard were used in the through-thickness (or z-direction) tensile tests. The thicknesses of paper and uncoated paperboard sheets were carefully measured with a high-precision digital micrometer under a constant pressure. The in-plane tensile properties were measured in both the machine and cross-machine directions and were found to vary greatly, depending on the specimen size, test direction and strain rate. The through-thickness tensile properties were presented only for uncoated paperboard, because of the experimental difficulties in the z-direction tensile tests on thin paper.

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The method of crack opening displacement (COD) has been used to obtain the energy release rate of fast propagating cracks just before and just after crack bifurcation. In the method, COD is measured on the microscopic photographs of the cracks. But, in the case of cracks in Araldite B, the corner made by a crack surface and a specimen surface is chipped out from the specimen, then, it is often difficult to measure CODs from the photographs of the cracks. The present study shows a method to measure the COD in the region where COD is difficult to be measured directly on the photograph. The accuracy of the method of the present paper is good enough that the measured CODs can give the energy release rate of the crack at bifurcation with the accuracy of about 7%.

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Experimental investigation has been carried out to understand the transition to turbulence in constant-acceleration pipe flow. A fluid initially at rest in a circular pipe is accelerated at a constant acceleration. The transition to turbulence is judged on the basis of the output signal of a hot-wire anemometer or laser Doppler velocimetry in addition to flow visualization. The critical Reynolds number,Re_tr(=u_mD⁄v), is highly increased beyond that of approximately 3000 in steady pipe flows, where u_m is the cross-sectional mean velocity, D is the pipe diameter, and v is the kinematic viscosity of fluid. The following empirical equation is proposed for the critical Reynolds number.Re_tr=1.33[D(a⁄v²)^1⁄3]^1.86 where a is the acceleration.

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Experimental investigation has been carried out to understand the propagation of turbulence and the related velocity distribution in a constant-acceleration pipe flow. Air is used as the working fluid and the axial velocity of air flow is measured with a hot-wire anemometer. Transition to turbulence is judged on the basis of the history of the axial velocity. Turbulence is generated near the wall in the entrance region and then propagates towards the centerline while traveling in the downward direction. The propagation pattern of turbulence depends on the acceleration. When the acceleration is smaller than a certain critical value, it is similar to that in steady pipe flow. Meanwhile, when the acceleration exceeds the critical value, turbulence propagates to the centerline even near the entrance of the pipe.

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Wavelet analysis has been carried out to understand the amplification of disturbances appearing prior to the transition to turbulence in a constant-acceleration pipe flow. Air is used as the working fluid and the axial velocity of air flow is measured with a hot-wire anemometer. Transition to turbulence is judged on the basis the histories of the axial velocity, RMS value of the axial velocity fluctuation, and wall shear stress in addition to the result of wavelet analysis. The period from the appearance of disturbances to the onset of turbulence is clarified in relation to the acceleration.

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Transition to turbulence of a laminar pipe flow accelerated from steady laminar state at a constant acceleration has been experimentally investigated. Air is used as the working fluid and the axial velocity component of the constant-acceleration flow near the entrance of the pipe is measured with a hot-wire anemometer. Transition to turbulence is judged based on the velocity signal and the RMS value of the velocity fluctuation. The results are compared with those obtained for a constant-acceleration pipe flow started from rest. The measured value of the critical Reynolds number in the former case is greater than that in the latter case. The amplification of disturbance does not occur when the initial flow is laminar unlike the case that the liquid is initially at rest.

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This report describes one of several new float polishing techniques with large clearance utilizing a newly developed magnetic responsive fluid, a magnetic compound fluid (MCF) developed by one of authors. In the present study, MCF was improved by the addition of α-cellulose, achieving a large clearance in float polishing. The present study utilized two float polishing tools, each producing a different kind of polishing motion. The polishing results show a finely polished, mirror-like surface with nm-order R_a for various kinds of material. The mechanism of the new polishing technique is explained in terms of a magnetic cluster model. In addition, the MCF float polishing effect is investigated by the fluid behavior on the polishing tool, normal stress, shear stress and behaviors of abrasive and magnetic particles in the fluid experimentally. The MCF float polishing effect depends on the large shear stress and behaviors of abrasive and magnetic particles. The results obtained by this polishing technique are also compared to those obtained using ordinary magnetic responsive fluids, i.e., magnetic fluid or magneto-rheological fluid.

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