scholarly journals A LN/Si-Based SAW Pressure Sensor

Sensors ◽  
2018 ◽  
Vol 18 (10) ◽  
pp. 3482 ◽  
Author(s):  
Pascal Nicolay ◽  
Hugo Chambon ◽  
Gudrun Bruckner ◽  
Christian Gruber ◽  
Sylvain Ballandras ◽  
...  
Keyword(s):  
Pressure Sensor ◽  
Wafer Bonding ◽  
Temperature Compensation ◽  
Mechanical Strain ◽  
Stress Fields ◽  
Wireless Devices ◽  
Response Curves ◽  
Temperature Changes ◽  
Set Up ◽  
Implantable Pressure Sensor

Surface Acoustic Wave (SAW) sensors are small, passive and wireless devices. We present here the latest results obtained in a project aimed at developing a SAW-based implantable pressure sensor, equipped with a well-defined, 30 μm-thick, 4.7 mm-in-diameter, Lithium Niobate (LN) membrane. A novel fabrication process was used to solve the issue of accurate membrane etching in LN. LN/Si wafers were fabricated first, using wafer-bonding techniques. Grinding/polishing operations followed, to reduce the LN thickness to 30 μm. 2.45 GHz SAW Reflective Delay-Lines (R-DL) were then deposited on LN, using a combination of e-beam and optical lithography. The R-DL was designed in such a way as to allow for easy temperature compensation. Eventually, the membranes were etched in Si. A dedicated set-up was implemented, to characterize the sensors versus pressure and temperature. The achieved pressure accuracy is satisfactory (±0.56 mbar). However, discontinuities in the response curve and residual temperature sensitivity were observed. Further experiments, modeling and simulations were used to analyze the observed phenomena. They were shown to arise essentially from the presence of growing thermo-mechanical strain and stress fields, generated in the bimorph-like LN/Si structure, when the temperature changes. In particular, buckling effects explain the discontinuities, observed around 43 °C, in the response curves. Possible solutions are suggested and discussed.

scholarly journals Design, Fabrication, and Implementation of a Wireless, Passive Implantable Pressure Sensor Based on Magnetic Higher-Order Harmonic Fields

Biosensors ◽  
2011 ◽  
Vol 1 (4) ◽  
pp. 134-152 ◽  
Author(s):  
Ee Lim Tan ◽  
Andrew J. DeRouin ◽  
Brandon D. Pereles ◽  
Keat Ghee Ong
Keyword(s):  
Pressure Sensor ◽  
Higher Order ◽  
Implantable Pressure Sensor

scholarly journals LED Rail Signals: Full Hardware Realization of Apparatus with Independent Intensity by Temperature Changes

Electronics ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 1291
Author(s):  
Giuseppe Schirripa Schirripa Spagnolo ◽  
Fabio Leccese
Keyword(s):  
Temperature Sensor ◽  
Energy Efficient ◽  
Light Emitting Diode ◽  
Junction Temperature ◽  
Light Emitting ◽  
Temperature Changes ◽  
Wide Range ◽  
International Regulations ◽  
Long Lifetime ◽  
Set Up

Nowadays, signal lights are made using light-emitting diode arrays (LEDs). These devices are extremely energy efficient and have a very long lifetime. Unfortunately, especially for yellow/amber LEDs, the intensity of the light is closely related to the junction temperature. This makes it difficult to design signal lights to be used in naval, road, railway, and aeronautical sectors, capable of fully respecting national and international regulations. Furthermore, the limitations prescribed by the standards must be respected in a wide range of temperature variations. In other words, in the signaling apparatuses, a system that varies the light intensity emitted according to the operating temperature is useful/necessary. In this paper, we propose a simple and effective solution. In order to adjust the intensity of the light emitted by the LEDs, we use an LED identical to those used to emit light as a temperature sensor. The proposed system was created and tested in the laboratory. As the same device as the ones to be controlled is used as the temperature sensor, the system is very stable and easy to set up.

A Study on the Lower Flanges Fracture of Endplate Bolted Connection

2006 ◽  
Vol 326-328 ◽  
pp. 983-986
Author(s):  
Hong Wei Ma ◽  
Chong Du Cho ◽  
Qiang Pan ◽  
Hyeon Gyu Beom
Keyword(s):  
Crack Length ◽  
High Stress ◽  
Transverse Load ◽  
Stress Fields ◽  
Finite Element Models ◽  
J Integral ◽  
Bolted Connection ◽  
Static Tests ◽  
Opening Mode ◽  
Set Up

The quasi-static tests on the endplate bolted connections of the new structure system consisting of SCC beam and CCSHRC column are briefly introduced in this paper. Meanwhile, the 3-D solid finite element models of the connections with pre-existing cracks in the lower flange’s high stress fields are set up by ANSYS. The material nonlinearities of concrete, steel and bars, together with the contact between the endplate and column surface are all considered in the model. With the transverse load applied on top of columns, the fracture parameters are calculated by APDL. The results indicate that the opening mode crack will happen mainly. When the pre-existing crack length is 2.50mm and the inter-storey drift is less than 6mm, the stress intensity factor values agree well with the converting values derived from J-integral and the crack tip fields are in elastic state. The J values are highly influenced by the pre-existing crack length, while seldom influenced by the concrete compression strength. Moreover, the J-integral have the trend to sharply increase when the pre-existing crack length is larger than 0.61mm, and the pre-existing crack will grow during loading when its length is larger than 1.35mm.

scholarly journals Automated monitoring system for events detection in sewer network by distribution temperature sensing data measurement

2018 ◽  
Vol 78 (7) ◽  
pp. 1499-1508
Author(s):  
Abdelhak Kessili ◽  
Jes Vollertsen ◽  
Asbjørn Haaning Nielsen
Keyword(s):  
Large Data ◽  
Temperature Sensing ◽  
Wastewater Discharge ◽  
Sewer Pipe ◽  
Temperature Changes ◽  
Set Up ◽  
Comparison Of The Results ◽  
Events Detection ◽  
High Level ◽  
Automated Tool

Abstract This study is related to distribution temperature sensing (DTS) in sewers for tracing illicit or unintended inflows to foul sewers. A DTS measurement is performed with a fiber optic cable that is installed at the invert of a sewer pipe in combination with a standalone laser/computer instrument. This set-up generates in-sewer temperature measurements with high resolutions in time (every minute) and space (every metre) along the cable over long periods of time (weeks on end). The prolonged monitoring period in combination with the high level of detail in the dataset allows the study of anomalies (i.e., unexpected temperatures and/or temperature variations at certain locations), even if these only occur very infrequently. The objective of this paper is to develop an automated tool to analyze the large data masses and identify anomalies caused by illicit or unintended inflows. In this study, an algorithm for detecting the temperature changes that are caused by both wastewater discharge and inflow of stormwater are developed. A comparison of the results of the automated procedure to the results of a manual assessment of the datasets (Elmehaven, Denmark) shows that the automated procedure performs very well.

Investigation on Temperature Compensation of Fiber Bragg Grating Sensors for Hull Monitoring

2018 ◽  
Author(s):  
Ruiqi Ma ◽  
Guoqing Feng ◽  
Huilong Ren ◽  
Peng Fu ◽  
Shuang Wu ◽  
...  
Keyword(s):  
Thermal Expansion ◽  
Fiber Bragg Grating ◽  
Temperature Compensation ◽  
Compensation Method ◽  
Bragg Grating ◽  
Theoretical Derivation ◽  
Temperature Changes ◽  
Hull Girder ◽  
Fbg Sensor ◽  
Fbg Sensors

Hull monitoring system with Fiber Bragg Grating (FBG) sensors increasingly receives people’s attentions. However, for the ship hull monitoring, the deformation of hull girder changes a lot as is subjected to a huge temperature variation. Therefore, the compensation method with only FBG temperature self-correction is not suitable for the hull monitoring sensors because no material thermal expansion effects are reasonably included. In this paper, the new compensation method of hull monitoring FBG sensor based on the sensor theory with both FBG temperature self-correction and steel thermal expansion effects correction is studied. The coupled compensation method suitable for hull monitoring sensor is obtained by theoretical derivation. As the comparison, the coupled compensation experiment was carried out. The results show that the relative error under the temperature compensation method is large in the case of drastic strain and temperature changes, and the correction results of the tested method will be closer to the true level.

scholarly journals Research on Temperature Compensation Method in Crankshaft Online Measurement System

2021 ◽  
Vol 11 (16) ◽  
pp. 7558
Author(s):  
Tingting Gu ◽  
Xiaoming Qian ◽  
Peihuang Lou
Keyword(s):  
Ambient Temperature ◽  
Measurement System ◽  
Temperature Compensation ◽  
Compensation Method ◽  
Displacement Sensor ◽  
Online Measurement ◽  
High Precision Measurement ◽  
Temperature Changes ◽  
Dragonfly Algorithm ◽  
Measuring Machine

The crankshaft online measurement system has realized the full inspection function with fast beats, at the same time it requires for high-precision measurement. Considering the effect of ambient temperature and temperature changes on measuring machine, the calibration part, the measured crankshaft and displacement sensor, a temperature compensation method is proposed. Firstly, relationship between calibration part and ambient temperature can be get through the zero calibration. Then use the material properties to obtain compensation values of the calibration part and the measured crankshaft part at different temperatures. Finally, the compensation parameters for displacement sensor can be obtained through the BP algorithm. The improved dragonfly algorithm (DA) is used to optimize the parameters of BP neural network algorithm. Experiments verify the effectiveness of IDA-BP for LVDT in temperature compensation. After temperature compensation, the error range of main journal radius is reduced from 0.0156 mm to 0.0028 mm, the residual error decreased from −0.0282 mm~+0.0018 mm to −0.0058 mm~−0.0008 mm. The influence of temperature changes on the measurement is reduced and measurement accuracy is improved through the temperature compensation method. The effectiveness of the method is proved.

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