A CASE OF GIANT FIBROUS BREAST TUMOR GOTO, Ryoichi; MINAMI, Masakazu; TAKAHASHI, Masato ...
Nihon Rinsho Geka Gakkai Zasshi (Journal of Japan Surgical Association),
2002, Letnik:
63, Številka:
7
Journal Article
Odprti dostop
A premenopausal 49-year-old, woman, who noted a mass in her right breast, 7 years earlier was admitted when the tumor occupied her entire right breast. Fine-needle aspiration cytology showed no ...epithelial cells. Core needle biopsy showed proliferated fibrous connective tissue. We could not distinguish this tumor from a phylloides tumor so we conducted a simple mastectomy, the cut surface of the tumor was whitish, solid, homogeneous, cyst-free and about 15cm at its greatest diameter. Microscopically, the lesion consisted of collagenous stroma with markedly decreased or absent ductal and lobular elements, which we diagnosed as a fibrous tumor. The tumor was the largest among previously reported fibrous tumors.
A new method for simple robust control of multimodes of vibration of flexible structures is proposed. Although robust control theories such as H∞ theory are useful for controlling systems with ...unknown factors and parameter variations, they are not effective for controlling multimodes of vibration of flexible structures. The proposed method combines the suboptimum control theory and two kinds of filtering technique for reducing the number of sensors and preventing spillover of neglected higher modes of vibration. Therefore, the method is called the filtered suboptimal control method. The effectiveness of the method is demonstrated by showing that the first five modes of vibration of a model structure of large bridge tower are well controlled without spillover of neglected higher modes.
The vibration of towers of suspended bridges due to strong wind has been of great concern to scientists and engineers. In this study, attention is given to the vibration control of a tall bridge ...tower under construction. An active control method is presented based on the lumped model of the bridge tower and the suboptimal control theory. Since the dynamic parameters of the tower differ under different phases of construction, it is necessary to reevaluate the corresponding model, nevertheless, the control strategy is maintained. Three typical construction phases of a bridge tower are considered in this paper. The modeling method and results of the simulation control are presented to illustrate the validity of the proposed method.
This report deals with a method for the natural vibration analysis of high speed semi-submergeble catamaran which is made up of two cylindrical lower hulls, struts and upper deck. The exact ...evaluation of added mass of water is inevitable to estimate the natural frequencies for such a structure, because vibration modes are fully three dimensional and are much different from the ordinary ship hull vibration modes. Therefore the authors present here a method to compose a three dimensional added mass matrix by use of J factor, which is well known as a three dimensional correction factor. The exciting tests of the experimental model were carried out, and the measured results showed a fairy good agreement with the calculated values obtained by the proposed method.
A fundamental study on vibration characteristics of the air cushion craft was performed taking dynamic behavior of the pneumatic seal structure into consideration. A linearized mathematical model of ...the air cushion craft dynamics was derived. The effect of each parameter on the dynamic stability was obtained analytically and experimentally from the view point of negative resistance excitation system. The conclusions are as follows : 1) The dynamic stability of pneumatic seal structural vibration depends on the air transmission line characteristics and the seal configuration. The effects of these parameters on the stability criteria of the system are numerically examined. 2) In the model test, the self excited vibration caused by the instability of the pneumatic seal system was observed in some range of the inlet area of fan and feedhole area in the air chamber. 3) The calculated fundamental natural frequency for air cushion craft model agreed very well with model test results. The stable region varied in accordance with feedhole area in the model test, and a similar tendencies were also observed in the numerical analysis. A further study is necessary to discuss the difference between model test results and numerical analysis results.
A Study on Vibration Characteristics of Large Ships Minami, Masakazu; Toyama, Yasumi; Abe, Sinichi
Journal of the Society of Naval Architects of Japan,
1978, 1978-00-00, Letnik:
1978, Številka:
144
Journal Article
Odprti dostop
This paper deals with a practical method for vibration analysis of large ships. The vibration characteristics for 230, 000 DWT oil tanker are also analyzed and compared with experimental results. The ...results obtained are as follows. 1) In estimating the vibration characteristics of large ships, a response factor of acceleration is effectively used, which is determined by the mode shape matrix and the generalized mass. 2) Although large ships usually have lots of eigen values, the vibration modes with large response factors are relatively few and localize upon some frequency regions. 3) The higher modes with large response factors are remarkable at superstructure and afterbody of shiphull. The response factors of their modes may considerably vary with the load condition, by which little frequency changes are observed. 4) The calculated and measured natural frequencies for the lower modes show good agreements. Although the data for the higher modes are not sufficient, it can be seen that the peak frequencies on the measured resonance curves correspond to those of the typical calculated vibration modes. 5) The calculated resonance curves are similar to the measured ones over a frequency range of 500 to 600 cpm except some cases. In general, further investigation will be required about estimating the exciting force, such as surface force induced by propeller and axial force of shaft system due to main engine.
The vibration of towers of suspended bridges due to strong wind has been of great concern to scientists and engineers. In this study, attention is given to the vibration control of a tall bridge ...tower under construction. An active control method is presented based on the lumped model of the bridge tower and the suboptimal control theory. Since the dynamic parameters of the tower differ under different phases of construction, it is necessary to reevaluate the corresponding model, nevertheless, the control strategy is maintained. Three typical construction phases of a bridge tower are considered in this paper. The modeling method and results of the simulation control are presented to illustrate the validity of the proposed method.
One of the principal causes of the fractures around the slot of transverse web is considered to be the effect of lateral vibration of transverse member. In this report, at first, exciting tests were ...carried out with the bottom trans. model of 1/4 scale actual ship in order to investigate the natural frequencies and modes in detail. Secondly, during the sea trial of 224, 841 DWT and 284, 495 DWT oil tanker, comprehensive vibration measurements of ship hull and bottom trans. were carried out and those data were used to find response characteristics and excitation sources. Finally, the theoretical analysis of natural frequency and hydrodynamic pressure for the lateral vibration of trans. member were carried out and the former results were compared with the measured values. The results obtained are as follows : (1) Calculated natural frequencies and modes except for modes in water showed considerably good agreement with those of the measurement. Natural frequency of 2 nd order in water is less than or nearly equal to one of the O-node axial vibration of shaft system. (2) Hydrodynamic pressure distribution depends on natural mode of member itself, correlation between adjacent ones and the shape of bracket and face plate. Therefore, further investigation is necessary to estimate virtual added mass. (3) Engine and propeller induced axial forces of shaft system are mainly transferred to the bottom trans. and amplified through axial vibration of shaft system and ship hull vibration.
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