NEW METHODS TO SOLVE HIGH ORDER POTENTIAL USED IN CALCULATING NON-LINEAR WAVE LOADS

ABSTRACT In the present study, non-linear wave loads such as the wave-drift force, wave-drift damping and wave-drift added mass, acting on the body is considered based on the potential theory. To investigate non-linear wave loads, consistent perturbation expansion by means of two small parameters, i.e. the incident wave slope and the low frequency body motion, is performed on a moving frame (body-fixed) coordinate system. To avoid complicated free surface integrals as much as possible, new approach for the higher order potential in the interaction problem of low frequency motion and waves is suggested in the present work. Instead of integrals, derivative operators are defined to obtain special solutions efficientl

In Vitro Study on Apoptosis Induced by Strontium-89 in Human Breast Carcinoma Cell Line

Many radiopharmaceuticals used for medical diagnosis and therapy are beta emitters; however, the mechanism of the cell death caused by beta-irradiation is not well understood. The objective of this study was to investigate the apoptosis of human breast carcinoma MCF-7 cell lines induced by Strontium-89 (89Sr) and its regulation and control mechanism. High-metastatic Breast Carcinoma MCF-7 cells were cultured in vitro using 89Sr with different radioactive concentration. The inhibition rate of cell proliferation was measured by MTT color matching method. The cell cycle retardation, apoptosis conditions, mitochondrion transmembrane potential difference and Fas expression were tested and analyzed. The genes P53 and bcl-2 expressions was also analyzed using immunity histochemical analysis. After being induced by 89Sr with various of radioactive concentration, it was found that the inhibition of cell proliferation of MCF-7 cells was obviously, the retardation of cell cycle occurred mainly in G2-M. It was also found that the obvious apoptosis occurred after being induced by 89Sr, the highest apoptosis rate reached 46.28%. The expressions of Fas acceptor and P53 gene increased, while bcl-2 gene expression decreasesd. These findings demonstrate that in the ranges of a certain radioactive concentration, the inhibition rate of MCF-7 cell proliferation and retardation of cell cycle had positive correlation with the concentration of 89Sr. And the mitochondrion transmembrane potential decrease would induce the apoptosis of MCF-7 cell notably, which were controlled by P53 and bcl-2 genes, involved with the Fas acceptor

特集7 : 研究速報 : An Asymptotic Solution for the Interaction Problems of Multiple Bodies in Short Ocean Waves

The asymptotic solutions for the diffraction and radiation problem of a vertical circle cylinder in short waves are applied to the interaction problem of multiple cylinders to obtain an estimation of hydrodynamic forces acting on cylinders. The interactions are represented by additional waves emitting from each cylinder towards the others. The hydrodynamic forces are evaluated by formulae at far field.小特集 海洋工

特集6 : 研究速報 : An Asymptotic Solution for the Diffraction Problem of a Vertical Circle Cylinder in Short Ocean Waves

An asymptotic solution for the diffraction problem of a circle cylinder in short waves is derived mathematically. Physically it represents the perfect reflection by the cylinder. Calculated results are in good agreement with those of the exact solution except in the 'shadowed area'.小特集 海洋工

NONLINEAR WAVE LOADS ACTING ON CYLINDER ARRAY SLOWLY OSCILLATING IN DIFFRACTION AND RADIATION WAVE FIELDS

ABSTRACT The problem of a circular cylinder array slowly oscillating in both diffraction and radiation wave fields is considered in the present work. As a result of the interaction between the wave fields and the low-frequency motion, nonlinear wave loads may be separated into the so-called wave-drift added mass and damping. They are force components proportional to the square of the wave amplitude but in phase of the acceleration and velocity of the low-frequency motion respectively. The frequency of the slow oscillation is assumed to be much smaller than the wave frequency. Perturbation expansion based on two time scales and two small parameters is performed to the order to include the effects of the acceleration of the lowfrequency motion. Solutions to these higher order potentials are suggested in the present work. Wave loads including the wave drift added mass and damping are evaluated by the integration of the hydrodynamic pressure over the instantaneous wetted body surface

海洋波の多列干渉問題の短波長域の漸近解

The asymptotic solutions for the diffraction and radiation problem of a vertical circle cylinder in short waves are applied to the interaction problem of multiple cylinders to obtain an estimation of hydrodynamic forces acting on cylinders. The interactions are represented by additional waves emitting from each cylinder towards the others. The hydrodynamic forces are evaluated by formulae at far field.小特集 海洋工

NON-LINEAR WAVE LOADS ACTING ON OBLIQUELY SLOWLY ADVANCING PLATFORM

ABSTRACT It is necessary to evaluate wave drift force for ships advancing obliquely. There are some approaches, for instance the strip method, solving the Navier-Stokes equation directly in the fluid domain (CFD), potential theory and so on. In the present study, the non-linear wave loads acting on the ship with constant oblique forward speed is considered based on the potential theory. Consistent perturbation expansion based on two parameters, i.e. the incident wave slope and the ratio of the forward speed compared to the phase velocity of the waves, is performed on a moving frame (bodyfixed) coordinate system to simplify the problem. So obtained boundary value problems for each order of potentials is solved by means of the hybrid method. The fluid domain is divided into two regions by an artificial circular cylinder surrounding the body. The potential in the inner region is expressed by an integral over the boundary surface with a Rankin source as its Green function while it is expressed in the eigen function expansion for the outer region. Consequently, the boundary value problems can be solved efficiently. In the present paper, the authors will discuss the effects of the obliquely advancing on the wave drift force in a diffraction wave field up to the order proportional to the advancing speed. An ellipsoid model is used in the calculation and the wave drift force is evaluated for various Froude number