Non-Destructive Inspection of Concrete Structures Using an Acceleration Pickup
The present paper proposes a method for detecting cracks or honeycombs in concrete structures using an acceleration pickup. The sensor on the concrete surface observes the stationary waves which are generated inside the structures depending on the depth of the crack (if there is a crack) or the bottom of the structure (if there are no cracks or honeycombs). The method measures the depths of the reflection planes (such as cracks or honeycombs) accurately by modeling the sensor output as an output of a linear dynamic system with unknown parameters and by applying a maximum likelihood method. The method is shown to be quite effectively applied to measure the depths of cracks and honeycombs
Fabrication of the micro-gripper with a force sensor for manipulating a cell
A novel micro-gripper has been designed and fabricated to manipulate the small object like a cell. In order to gripping the cell, it should be no restriction to use the micro-gripper in the water. Since the mechanical type micro-gripper is little affected by a surrounding so as to use freely in any environment, compared with other type micro-grippers, it is suitable to treat the cell. In addition, it can reduce the deformation of the cell and control the gripping force flexibly. A point to be considered to manipulate the cell is the force working on the cell and the deformation of the cell according to the applied force. On the gripper a piezo-resistive sensor is integrated for sensing the gripping force. Using the fabricated micro-gripper, micro-glass beads can be successfully manipulated in the water. The resistor of the piezoresistive sensor is successfully changed according to the force on the micro-gripper. If on-going feedback experiment in the gripper system is finished successfully, the proposed micro-gripper can be utilized for manipulating the cell
Communicative Competence: Theory and Classroom Practice
ABSTRACT Within the framework of viewing communicative competence as a prerequisite to linguistic competence, rather than vice versa, this paper considers the following: (1) the nature of communicative competence; (2) the implications of communicative competence for second language teaching; and (3) ways in which the teacher can begin to make a foreign language program more meaningful. Communicative competeuce is defined as what native speakers know which enables them to interact effectively with each other. Implications for the language teacher include: (T) the need for tests which measure the ability to use language; (2) the irrelevancy of sequencing surface features; (3) the need for emphasis on non-lizguistic aspects of communication; and (4) the need to re-examiLe attitudes toward students and language teaching. Practical suggestins for implementing communicative competence in the classroom include the use of spontaneous role-playing, discussions, games, radio, and the telephone. (AM)