Observation of Microscopic Deformation Behavior of Cork

Cork is a material that has many characteristics, for instance, light weight, elasticity, insulation against heat, impermeability for liquid, and so forth. There are two types of cork, the natural and the agglomerated corks. In the present paper, compression tests of the natural and the agglomerated cork specimens were carried out. The compression test were done in various directions. Compressive stress was measured by a original compression apparatus, and stress-strain curves were obtained in various directions of the cork specimens. In the natural cork, there are differences between the radial and the non-radial direction. The recovery of dimensions after compression was also studied in respective directions. The structure of the deformed surface was observed by a scanning electron microscope

LINEAR AND ANGULAR MOMENTUM OF THE UPPER BODY IN TENNIS FOREHANDS

Linear momentum and angular momentum are said to be the two sources of power in the tennis forehand and they “should act together in a coordinated manner” (Groppel, 1992). However, the relationship between them has not been investigated. Thus, the purposes of this study were to determine linear and angular momentum of the upper body in tennis forehands and to investigate their coordination

The possibility of concrete production on the Moon

When a long-term lunar base is constructed, most of the materials for the construction will be natural resources on the Moon, mainly for economic reasons. In terms of economy and exploiting natural resources, concrete would be the most suitable material for construction. This paper describes the possibility of concrete production on the Moon. The possible production methods are derived from the results of a series of experiments that were carried out taking two main environmental features, low gravity acceleration and vacuum, into consideration

Microscopic Observation of Plastic Deformation of Polycrystalline Aluminum by Laser Scanning Microscope

Free surface of polycrystalline metal becomes roughened after plastic deformation. The surface roughening is closely related to the inhomogeneity of polycrystalline metals, that is, to the inhomogeneous plastic deformation of respective grains. In the present study, inhomogeneous deformation on the free surface of polycrystalline aluminum specimen during uniaxial tension is studied. The inhomogeneous deformation of grains in the central area of the free surface of specimen is observed by the laser scanning microscope, while the inhomogeneous deformation perpendicular to the surface is studied by the laser scanning microscope as well as the stylus measuring instrument. It is shown that the surface roughness and the strain of respective grains increase with the applied strain. Discussions are made on the change in the surface roughness, the strain in each grain and the slip-line angles with the applied strain

55Mn NMR in Mn12 acetate: Hyperfine interaction and magnetic relaxation of cluster

The 55Mn NMR in oriented powder Mn12Ac has been investigated at 1.4-2.0 K in zero field and with external fields along the c-axis. Three kinds of 55Mn NMR composed of five-fold quadrupole-split lines for I=5/2 nuclei have been interpreted to arise from Mn4+ ion, and two crystallographically-inequivalent Mn3+ ions, respectively. It is found that the isotropic hyperfine field in the Mn4+ ion with 3d3 configuration indicates a large amount of reduction (26%) as compared with the theoretical evaluation. In the analysis for the hyperfine field of Mn3+ ions with 3d4 configuration, we have taken into account of the anisotropic dipolar contribution in addition to the Fermi-contact term in order to explain two kinds of 55Mn NMR frequencies in Mn3+ ions in inequivalent sites. By using the hyperfine coupling constants of twelve manganese ions in Mn12Ac, the total hyperfine interaction of the ferrimagnetic ground state of S=10 has been determined to amount to 0.3 cm-1 in magnitude at most, the magnitude of which corresponds to the nuclear hyperfine field he(0.32 kG seen by Mn12 cluster spin. The relaxation of the cluster magnetization was investigated by observing the recovery of the 55Mn spin-echo intensity in the fields of 0.20-1.90 T along the c-axis at 2.0 K. It was found that the magnetization of the cluster exhibits the (t-recovery in the short time regime. The relaxation time decreases with increasing external field following significant dips at every 0.45 T. This is interpreted to be due to the effects of thermally-assisted quantum tunneling between the spin states at magnetic level crossings.Comment: Text 25 pages, five figures and two table

PHYSIOLOGICALLY REASONABLE ‘TORQUE REVERSAL’ CAUSED IN COMPUTERSIMULATED PLANAR BALL THROWING DOES NOT INCREASE BALL SPEED AT RELEASE

INTRODUCTION: Herring and Chapman (1992) reported that some torque reversals caused by the agonist deactivation and the antagonist activation at the proximal joints of a planar three link segment model for ball throwing with the upper extremity increased ball speed at ball release. The paper has often been referred as the study showing possible positive roles of antagonisms for planar motions (Sorensen et al. 1996; Do”rge et al., 1999) in spite of its unrealistically rapid torque reversal for human movements. The purpose of this study was to investigate influences of the speeds of the deactivation and activation on the ball speed in computer-simulated ball throwing using a model similar to that used by Herring and Chapman (1992)

Hamiltonian tomography of dissipative systems under limited access: A biomimetic case study

The identification of parameters in the Hamiltonian that describes complex many-body quantum systems is generally a very hard task. Recent attention has focused on such problems of Hamiltonian tomography for networks constructed with two-level systems. For open quantum systems, the fact that injected signals are likely to decay before they accumulate sufficient information for parameter estimation poses additional challenges. In this paper, we consider use of the gateway approach to Hamiltonian tomography \cite{Burgarth2009,Burgarth2009a} to complex quantum systems with a limited set of state preparation and measurement probes. We classify graph properties of networks for which the Hamiltonian may be estimated under equivalent conditions on state preparation and measurement. We then examine the extent to which the gateway approach may be applied to estimation of Hamiltonian parameters for network graphs with non-trivial topologies mimicking biomolecular systems.Comment: 6 page