Hazime Inagaki

EVALUATION OF RIDING COMFORT: FROM THE VIEWPOINT OF INTERACTION OF HUMAN BODY AND SEAT FOR STATIC, DYNAMIC, LONG TIME DRIVING

Until now, seat riding comfort has been studied mainly using dynamic vibration analysis; and there are few studies that give importance to the sensory characteristics of the driver and passengers. In order to apply to the design of comfortable seating, the authors developed a new seat evaluation method that emphasizes the interaction between the human body and the seat. For static seating comfort, they determined seat compliance as a new evaluation index by using a human body pressure distribution that is calculated by dividing the seat into 16 segments, and is related to seat flexion. For dynamic riding comfort, speed of the human body pressure distribution, and the acceleration of each human body part were made into an index. For long-term sitting fatigue, physiological data such as stress hormone density and electromyogram data also were made into an index. Finally, to quantify the conventional sensory evaluation, the authors matched the physical and physiological data with sensory evaluation data. For the covering abstract of the conference see ITRD E206480.

Monolithic pressure-flow sensor

A new silicon-based monolithic pressure-flow sensor has been developed. Its operation is based on the piezoresistive effect for pressure sensing and heat transfer for flow sensing. The sensor chip has a thermal isolation structure that is made of an oxidized porous silicon membrane. This structure thermally isolates the heating element located on the membrane from the rim of the chip. The sensor, in which the chip was mounted on a wall of an acrylate plastic pipe, was designed for biomedical applications. Measurements were made at pressures of 0-300 mmHg, water flow rates of 0-7 1/min, and fluid temperatures of 25-45°C. The temperature difference between the heating element and the fluid temperature sensing element was kept at 5°C. The sensor showed a pressure sensitivity of 1.32 µV/mmHg for 1-mA current supplied, a nonlinearity of 0.5 %F.S. for pressure sensing, an accuracy of ±10 %F.S. for flow sensing, and 90-percent response time of below 100 ms for flow sensing. The sensor was applied to the simultaneous measurements of pressure and flow rate in pulsedflow experimental systems.

ISFET's with ion-sensitive membranes fabricated by ion implantation

Ion sensitive FETs (ISFETs) for sodium ions (Na/sup +/) fabricated by ion-implantation are investigated. The sensing layers are produced by implanting Na/sup +/ ions into the surface of an oxidized Si/sub 3/N/sub 4/ layer through an Al buffer layer deposited beforehand, in order to reduce the damage to the gate insulator of the ISFET during ion implantation. The Na/sup +/ sensitivity, selectivity, repeatability, thermal characteristics, and long-term stability are evaluated. The ISFET responds to Na/sup +/ ions independent of pH within the range of pH 7-10, and the Na/sup +/ sensitivity is nearly Nernstian. The ISFETs repeatability and long-term stability (about 1300 h), suggests that the ion-implantation technique is a suitable method for fabricating a stable ion-sensing layer. >

Multiple ion sensor array

Abstract The remarkable progress in the technology of semiconductor fabrication over the past 10 years has accelerated the development of many multiple ion sensor arrays. We have also fabricated a compact multi-ion sensor, which enables simultaneous measurements of H+, Na+ and K+ ion concentrations to be made with a small amount of a sample. The sensor is expected to be an effective clinical device for rapid ion concentration measurements at the patients bedside. This paper first reviews some developments reported previously, then describes our multi-ion sensor and finally discusses remaining problems.

Study of breath alcohol detector

A novel detector of breath alcohol for a driver has been developed. The detector has three features. A mouth piece is not required because drivers breath is introduced to the detector by a suction pump. The influence of fluctuations of drivers breath flow is extremely reduced by the calibration of alcohol concentration using a humidity change. The detector is able to measure breath alcohol concentration rapidly, and the measurement time is about 2 to 3 seconds. The excellent performance have been demonstrated both in breath alcohol simulation tests and in a drunken persons test.