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temperature-sensors
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Spatial resolution enhancement in fiber Raman distributed temperature sensor by employing ForWaRD deconvolution algorithm
, Article Optical Fiber Technology ; Volume 17, Issue 2 , 2011 , Pages 128-134 ; 10685200 (ISSN) ; Moosavi, A ; Bahrampour, M. J ; Safaei, L ; Sharif University of Technology
Abstract
Governing equations of a Raman fiber distributed temperature sensor supported by a counter propagating pumped Raman amplifier are written in the form of integral equations. Forward pump and backward going probe are in the pulsed and continuous wave modes of operation respectively. It is shown that powers of the forward and backward Raman signals (stokes and anti stokes) approximately are the convolution of the input forward pump pulse and corresponding optical fiber impulse responses. The Fourier Wavelet Regularized Deconvolution (ForWaRD) method is employed to improve the spatial resolution in fiber Raman distributed temperature sensor without reducing the pulse width of the laser source
Design of low-power temperature sensor architecture for passive UHF RFID tags
, Article Informacije MIDEM ; Volume 45, Issue 4 , 2015 , Pages 249-259 ; 03529045 (ISSN) ; Kamarei, M ; Ahmady, A. F ; Sharif University of Technology
Society for Microelectronics, Electric Components and Materials
2015
Abstract
A low-power wide-range CMOS temperature sensor architecture is proposed based on temperature-to-frequency conversion using supply voltage controlled sub-threshold ring oscillator. The principles of operation are investigated and proved via analytic and simulation results. Most errors are canceled out by this ratio-metric design. An inaccuracy of -0.84°C to +0.34°C occurs over a range of -40°C to 80°C after using a novel in-field digital two-point calibration. The entire sensor consumes less than 93nW to 305nW over the temperature range and can be digitally reconfigured for setting sample rate and resolution in a tradeoff
A low-power smart temperature sensor for passive UHF RFID tags and sensor nets
, Article 2016 8th International Symposium on Telecommunications, IST 2016, 27 September 2016 through 29 September 2016 ; 2017 , Pages 12-17 ; 9781509034345 (ISBN) ; Kamarei, M ; Fotowat Ahmady, A ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2017
Abstract
A low-power wide-range CMOS temperature sensor architecture is proposed for RFID and Sensor Networks based on temperature-to-frequency conversion using supply voltage controlled sub-threshold ring oscillator. The principles of operation are investigated and proved via simulation results. Most errors are canceled out by this ratio-metric design. An inaccuracy of -0.84°C to +0.34°C occurs over a range of -40°C to 80°C after using a novel in-field digital two-point calibration. The entire sensor consumes less than 93nW to 305nW over the temperature range and can be digitally reconfigured for setting sample rate and resolution in a tradeoff. © 2016 IEEE
Modeling and Identification of Satellite Thermal Radiation Model for Attitude Estimation Using Temperature Sensors
, M.Sc. Thesis Sharif University of Technology ; Pourtakdoust, Hossein (Supervisor) ; Kiani, Maryam (Supervisor)
Abstract
Attaining accurate information about satellite attitude is one of the most important requirements in space missions in order to improve the accuracy of the satellite control and mission objectives. Many different sensors such as sun sensor, star sensor, horizon sensor, etc. are used to estimate spacecraft’s attitude. Attitude estimation using temperature sensors is a topic that has recently been addressed by some related researchers because, they need less power and budget to operate in comparison with the other sensors.Accuracy and heat model performance improvement is the main purpose of this project. To achieve a more accurate perspective of space thermal model, and the way heat transfers...
Design of spherical vessels under steady-state thermal loading using thermo-elasto-plastic concept
, Article International Journal of Pressure Vessels and Piping ; Volume 86, Issue 2-3 , 2009 , Pages 143-152 ; 03080161 (ISSN) ; Kargarnovin, M. H ; Naghdabadi, R ; Sharif University of Technology
2009
Abstract
Governing equilibrium equations of thick-walled spherical vessels made of material following linear strain hardening and subjected to a steady-state radial temperature gradient using elasto-plastic analysis are derived. By considering a maximum plastic radius and using the concept of thermal autofrettage for the strengthening mechanism, the optimum wall thickness of the vessel for a given temperature gradient across the wall thickness is obtained. Finally, in the case of thermal loading on a vessel, the effect of convective heat transfer on the optimum thickness is studied and a general formula for the optimum wall thickness and design graphs for several different cases are presented. © 2008...
Monitoring of Structure Characteristics, Humidity, Temperature and Torsion Using Optical Fiber Sensor
, Ph.D. Dissertation Sharif University of Technology ; Bahrampour, Alireza (Supervisor) ; Tofighi, Sara (Supervisor)
Abstract
Fiber optic sensors have found industrial applications due to their unique characteristics and wide range of environmental parameters. Specifically, distributed optical fiber sensors which have applications in borders protection, intrusion detection, oil and gas leakage detection and smart irrigation of farms and gardens, have attracted significant attention from research groups around the world in recent years. According to the forecasts, among all kind of optical fiber sensors, the temperature and acoustic/vibration sensors will seize the market during the coming years. In this thesis, three kind of optical fiber sensors are proposed for environment health monitoring. First, distributed...
Prediction of solidification behaviour of weld pool through modelling of heat transfer and fluid flow during gas tungsten arc welding of commercial pure aluminium
, Article Materials Science and Technology ; Volume 24, Issue 12 , 2008 , Pages 1427-1432 ; 02670836 (ISSN) ; Serajzadeh, S ; Kokabi, A. H ; Sharif University of Technology
2008
Abstract
A mathematical model is developed to assess the solidification behaviour of the weld pools. To do so, during gas tungsten arc welding of commercial pure aluminium, equations of conversation of mass, energy and momentum are numerically solved considering three-dimensional steady state heat transfer and fluid flow conditions. The weld pool geometry, weld thermal cycles and various solidification parameters are calculated using temperature and velocity fields acquiring from the utilised model. The solidification behaviour of the weld pool at the weld centreline and the fusion line is then studied using the solidification parameters including temperature gradient G, solidification rate R and the...
A new low voltage precision CMOS current reference with no external components
, Article IEEE Transactions on Circuits and Systems II: Analog and Digital Signal Processing ; Volume 50, Issue 12 , 2003 , Pages 928-932 ; 10577130 (ISSN) ; Atarodi, S. M ; Sharif University of Technology
2003
Abstract
A novel current reference with low temperature and supply sensitivity and without any external component has been developed in a 0.25 μm mixed-mode process. The circuit is based on a bandgap reference (BGR) voltage and a CMOS circuit similar to a beta multiplier. An NMOS transistor in triode region has been used in place of a resistor in conventional beta multiplier to achieve a current which has a negative temperature coefficient and only oxide thickness dependent. The BGR voltage has a positive temperature coefficient to cancel the negative temperature coefficient of the beta multiplier. The simulation results using Bsim3v3 model show max-to-min fluctuation of less than 1 % over a...
Dissipation factor as a degradation indicator for electrolytic capacitors
, Article IEEE Journal of Emerging and Selected Topics in Power Electronics ; 2022 , Pages 1-1 ; 21686777 (ISSN) ; Peyghami, S ; Mokhtari, H ; Wang, H ; Blaabjerg, F ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2022
Abstract
Capacitors are one of the most critical components in power electronic converters, yet they are notoriously susceptible to failure. Avoiding unforeseen outages caused by capacitor failures is one of the most effective approaches to increase system availability. Therefore, a variety of methods have been proposed to monitor a capacitor health condition based on different degradation indicators. This paper proposes a new approach based on the accurate measurement of an electrolytic capacitor dissipation factor to detect its end-of-life. Since the dissipation factor is affected by both the capacitor resistance and capacitance simultaneously, it can provide more information about the health...