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Cell wall mechanical properties of closed-cell Al foam
Jeon, Insu,Katou, Kiyotaka,Sonoda, Tsutomu,Asahina, Tadashi,Kang, Ki-Ju Elsevier 2009 Mechanics of materials Vol.41 No.1
<P><B>Abstract</B></P><P>The mechanical properties of the cell wall, such as the elastic modulus, 0.2% offset yield stress and power-law hardening exponent of the closed-cell Al foam are determined using both experimental measurements and finite element analyses. A 6×6×12cm<SUP>3</SUP> ingot of the cell wall base material, which is sampled from melted Al-1.5wt.%Ca alloy before foaming, is prepared, and its mechanical properties are initially measured to set the limit values of the mechanical properties of the Al cell wall. Two 5×5×5mm<SUP>3</SUP> Al foam specimens of completely different structures are fabricated, and directly modeled for the finite element analysis by using a microfocus X-ray CT system, 3D reconstruction program, 3D scanned data processing software, and commercial mesh generation program. Subsequently, uniaxial compression tests are carried out on the specimens, and the numerical simulations of these tests are performed using the finite element models. For the simulations, various mechanical properties for the cell wall selected from the measured properties of the base material are used. Then, the Al cell wall mechanical properties are precisely determined by comparing the computed force–displacement curves with the measured ones. Finally, the effects of each mechanical property on the compressive behavior of the foam material are analyzed.</P>
Miyauchi, H.,Katou, N.,Tanaka, K. Elsevier Scientific Pub. Co 2011 Journal of wind engineering and industrial aerodyn Vol.99 No.11
The wind pressure, billow of a PVC sheet, and fastener load of a mechanically anchored waterproofing membrane system on a building rooftop were measured during a typhoon. The results showed that the waterproof sheet billowed upward, and the height of the billow was greater on the windward side that was under higher negative pressure. The axial and lateral forces acting on the fastener of the waterproof sheet were measured by a six-component force transducer, and it was found that the lateral force acting on the windward side of the fastener was larger. The tensile force acting on the fastener section was calculated using an equation for rooftop wind pressure. Finally, the method used to determine the fastener's position and the types of materials best-suited to cope with wind pressure on the roof were proposed, and the safety of this waterproof system was evaluated.
Pudcharaporn Kromkhun,Masahiro Katou,Haruo Hashimoto,Misao Terada,Changjong Moon,Toru R. Saito 한국실험동물학회 2013 Laboratory Animal Research Vol.29 No.2
Ultrasonic vocalizations (USVs) are essential communicative sounds used between rodent pups and their mother. Rat pups emit USVs in stressful situations, such as when they are cold or separated from the nest. We verified the ontogenetic changes in USVs emitted by infant rats isolated from their mother during the pre-weaning period. The number of calls, and the median frequency and first peak of frequency of the calls were measured at 1, 3, 5, 7, 10, 12, and 14 days postnatal age in Wistar-Imamichi rats. Pups were placed in a cold glass beaker and USVs were recorded for 5 min. The number of calls increased to a peak on day 5 and then gradually decreased. The median frequency of calls decreased slowly during the first 12 days, and then increased slightly on day 14. Similarly, the first peak frequency of calls was the highest on day 1, and then decreased gradually by day 12. A small increase was observed on day 14. These changes in frequency were correlated with the physical development of the pups, whose body weights increased significantly with age except during postnatal days 7-10.