Sub g Threshold Acceleration Sensor Incorporating Latched Bistable Beam

2018 ◽  
Author(s):  
Lior Medina ◽  
Rivka Gilat ◽  
Slava Krylov
Keyword(s):  
Feasibility Study ◽  
Geometric Parameters ◽  
Acceleration Sensor ◽  
High Stiffness ◽  
Micro Sensor ◽  
Acceleration Force ◽  
Inertial Switch ◽  
External Acceleration ◽  
Buckled State

We present a concept and a theoretical feasibility study of a sub g threshold inertial micro sensor, which incorporates a curved bistable beam as a suspension element. For certain range of geometric parameters such a beam can exhibit lathing, namely remain in its switched configuration at zero actuating force. Since the device can be released from its latched state by an external acceleration force, it can therefore serve as a threshold inertial switch. While the snap-through force, associated with the switching from the initial to the buckled state, cannot be reduced without decreasing the frequency of the device, the release value of the acceleration can be tailored to be arbitrarily low. This allows design of a devices with sufficiently high stiffness in the initial and latched configurations, but with a very low release threshold. Our model show that for appropriately chosen parameters, it is possible to design a sub g threshold acceleration micro switch of realistic dimensions.

Characteristic Evaluation of Silicon-Based MEMS Acoustic/Acceleration Sensor

2007 ◽  
Author(s):  
Ru-Min Chao ◽  
Sie-Yu Li ◽  
Chih-Chao Hsu ◽  
Steven Y. Liang
Keyword(s):  
Monitoring System ◽  
Water Tank ◽  
Acceleration Sensor ◽  
Vibration Signals ◽  
Batch Fabrication ◽  
Economic Saving ◽  
Potential Applications ◽  
Micro Sensor ◽  
Silicon Based ◽  
Structure Layer

Due to its smallness in size and economic-saving in batch fabrication, the acoustic micro sensor shows many potential applications in the field of manufacturing and machining monitoring system if it can help to pick up information of sound and vibration signals at specific range. In this paper, brief discussion for the design of the micro-sensor and its fabrication issue will be made. Fundamental frequency testing results by the piezo-electric shaker and acoustic measurement within the water tank are given. A 6-inch silicon wafer fabrication process and sensor design having resonant frequency in the range of 20k–60k Hz are presented and discussed. By selecting appropriate thickness of the structure layer on a SOI wafer, it is possible to customer-make a micro-sensor to sense within a given-range of interest and to apply it in a manufacturing monitoring system.

Feasibility Study on Design of Spindle Supported by High-Stiffness Water Hydrostatic Thrust Bearing

2014 ◽  
Vol 8 (4) ◽  
pp. 530-538 ◽  
Author(s):  
Yohichi Nakao ◽  
◽  
Kenji Suzuki ◽  
Kohei Yamada ◽  
Kohei Nagasaka
Keyword(s):  
Feasibility Study ◽  
Machine Tools ◽  
Water Pressure ◽  
Machining Accuracy ◽  
Thrust Bearings ◽  
High Stiffness ◽  
Precision Machine ◽  
Ultra Precision ◽  
Bearing Stiffness ◽  
Precision Machine Tools

The machining accuracy of ultra-precision machine tools relies on the performance of the spindle and linear table. The machining accuracy of ultra-precision machine tools is now at the level of several tens of nanometers. In order for ultra-precision machine tools to achieve machining accuracy, a precise spindle system is indispensible. High bearing stiffness is particularly important to minimize displacement due to the cutting force. This paper considers a spindle design supported by high-stiffness water hydrostatic thrust bearings. An objective of this study is to design a precision spindle supported by water hydrostatic thrust bearings with 1 kN/µm bearing stiffness. The bearing restrictors are chosen so that the highest stiffness can be obtained for given bearing parameters. The influences of gap sizes and supply water pressure on the bearing stiffness are presented. Based on the feasibility study done on the design of highstiffness water hydrostatic thrust bearings, the spindle is designed and developed. The influences of the water pressure on the spindle deformation and bearing stiffness are also investigated.

Lectin-Induced RBC Agglutination: Chemical vs. Cryofixation

1980 ◽  
Vol 38 ◽  
pp. 664-665
Author(s):  
Dean A. Handley ◽  
Lanping A. Sung ◽  
Shu Chien
Keyword(s):  
Lectin Binding ◽  
Freeze Substitution ◽  
Electrostatic Charge ◽  
Geometric Parameters ◽  
Comparative Approach ◽  
Chemical Fixation ◽  
Cell Surfaces ◽  
Minimal Cell ◽  
Membrane Stiffness ◽  
Cell Contour

RBC agglutination by lectins represents an interactive balance between the attractive (bridging) force due to lectin binding on cell surfaces and disaggregating forces, such as membrane stiffness and electrostatic charge repulsion (1). During agglutination, critical geometric parameters of cell contour and intercellular distance reflect the magnitude of these interactive forces and the size of the bridging macromolecule (2). Valid ultrastructural measurements of these geometric parameters from agglutinated RBC's require preservation with minimal cell distortion. As chemical fixation may adversely influence RBC geometric properties (3), we used chemical fixation and cryofixation (rapid freezing followed by freeze-substitution) as a comparative approach to examine these parameters from RBC agglutinated with Ulex I lectin.

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