scholarly journals A suitable (wide-range + linear) temperature sensor based on Tm3+ ions

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
A. R. Zanatta ◽  
D. Scoca ◽  
F. Alvarez
Keyword(s):  
Temperature Sensor ◽  
Linear Temperature ◽  
Wide Range

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.

Parametric Models of Ultrasonic Piezoelectric Transducers over a Wide Temperature Range

2015 ◽  
Vol 2015 (HiTEN) ◽  
pp. 000266-000272 ◽  
Author(s):  
Steven A. Morris ◽  
Jeremy Townsend
Keyword(s):  
Dielectric Constant ◽  
Temperature Dependence ◽  
Coupling Coefficient ◽  
Thin Disk ◽  
Piezoelectric Transducers ◽  
Parametric Models ◽  
Model Parameters ◽  
Linear Temperature Dependence ◽  
Linear Temperature ◽  
Wide Range

Piezoelectric ultrasonic transducers are used extensively in well logging and logging-while-drilling applications for pulse-echo operation. We present a method of modeling the operation of ultrasonic thin-disk piezoelectric transducers over a wide range of temperatures. The model is based on using Redwood's version of Mason's model of thin-disk transducers. Laboratory measurements in the oven of non-backed transducers in air are used to extract the Mason model parameters as a function of temperature. Derived parameters are frequency-thickness constant, dielectric constant, and thickness mode coupling coefficient. A fourth parameter, bulk density, is measured independently and assumed constant over temperature. Temperature dependence of frequency thickness constant and coupling coefficient are modeled as linear temperature coefficients. Temperature dependence of the dielectric constant must be specified as a table because of the non-linear temperature dependence of that parameter.

scholarly journals Liquid-Filled Highly Asymmetric Photonic Crystal Fiber Sagnac Interferometer Temperature Sensor

Photonics ◽  
2020 ◽  
Vol 7 (2) ◽  
pp. 33 ◽  
Author(s):  
Yashar E. Monfared ◽  
Amir Ahmadian ◽  
Vigneswaran Dhasarathan ◽  
Chunhao Liang
Keyword(s):  
Photonic Crystal ◽  
Photonic Crystal Fiber ◽  
Temperature Sensor ◽  
The Finite Element Method ◽  
Sagnac Interferometer ◽  
Linear Temperature ◽  
Modal Birefringence ◽  
Ambient Temperatures ◽  
Crystal Fiber ◽  
Fiber Design

In this paper, we theoretically designed and numerically studied a high-resolution and ultrasensitive photonic crystal fiber temperature sensor by selective filling of a liquid with high thermo-optic coefficient in one of the airholes of the fiber. The finite element method was utilized to study the propagation characteristics and the modal birefringence of the fiber under different ambient temperatures. A large base birefringence value of 7.7 × 10−4 as well as a large birefringence sensitivity of almost 29% to a 10 °C temperature variation was achieved for the optimized fiber design with liquid chloroform between 15 °C and 35 °C. We also studied the performance of the proposed optical fiber in a temperature sensing Sagnac interferometer. An average linear temperature sensitivity of 17.53 nm/°C with an average resolution of 5.7 × 10−4 °C was achieved over a temperature range of 20 °C (15 °C to 35 °C).

scholarly journals Strange metallicity in the doped Hubbard model

Science ◽  
2019 ◽  
Vol 366 (6468) ◽  
pp. 987-990 ◽  
Author(s):  
Edwin W. Huang ◽  
Ryan Sheppard ◽  
Brian Moritz ◽  
Thomas P. Devereaux
Keyword(s):  
Hubbard Model ◽  
Quantum Monte Carlo ◽  
High Temperature Superconductors ◽  
Linear Temperature Dependence ◽  
Strongly Correlated ◽  
Linear Temperature ◽  
Strongly Correlated Materials ◽  
Starting Point ◽  
Wide Range ◽  
Degenerate Regime

Strange or bad metallic transport, defined by incompatibility with the conventional quasiparticle picture, is a theme common to many strongly correlated materials, including high-temperature superconductors. The Hubbard model represents a minimal starting point for modeling strongly correlated systems. Here we demonstrate strange metallic transport in the doped two-dimensional Hubbard model using determinantal quantum Monte Carlo calculations. Over a wide range of doping, we observe resistivities exceeding the Mott-Ioffe-Regel limit with linear temperature dependence. The temperatures of our calculations extend to as low as 1/40 of the noninteracting bandwidth, placing our findings in the degenerate regime relevant to experimental observations of strange metallicity. Our results provide a foundation for connecting theories of strange metals to models of strongly correlated materials.

scholarly journals A CMOS-Thyristor Based Temperature Sensor with +0.37 °C/−0.32 °C Inaccuracy

Micromachines ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 124 ◽  
Author(s):  
Jing Li ◽  
Yuyu Lin ◽  
Siyuan Ye ◽  
Kejun Wu ◽  
Ning Ning ◽  
...  
Keyword(s):  
Power Consumption ◽  
Temperature Sensor ◽  
Current Source ◽  
Average Power ◽  
Bias Current ◽  
Cmos Process ◽  
Linear Temperature ◽  
Temperature Characteristics ◽  
Period Ratio ◽  
Average Power Consumption

This paper describes a voltage controlled oscillator (VCO) based temperature sensor. The VCOs are composed of complementary metal–oxide–semiconductor (CMOS) thyristor with the advantage of low power consumption. The period of the VCO is temperature dependent and is function of the transistors’ threshold voltage and bias current. To obtain linear temperature characteristics, this paper constructed the period ratio between two different-type VCOs. The period ratio is independent of the temperature characteristics from current source, which makes the bias current generator simplified. The temperature sensor was designed in 130 nm CMOS process and it occupies an active area of 0.06 mm2. Based on the post-layout simulation results, after a first-order fit, the sensor achieves an inaccuracy of +0.37/−0.32 °C from 0 °C to 80 °C, while the average power consumption of the sensor at room temperature is 156 nW.

Surface Plasmon Resonance based optical temperature sensor using ZnO:N thin film

2012 ◽  
Vol 1399 ◽  
Author(s):  
Kajal Jindal ◽  
Monika Tomar ◽  
Vinay Gupta
Keyword(s):  
Thin Film ◽  
Dielectric Constant ◽  
Surface Plasmon ◽  
Temperature Sensor ◽  
Low Cost ◽  
Temperature Dependent ◽  
Technique Effect ◽  
Wide Range ◽  
Optical Temperature Sensor ◽  
Promising Application

ABSTRACTTemperature dependent optical properties of RF-sputtered c-axis oriented ZnO:N thin film have been investigated. Surface Plasmon modes are excited at the metal-dielectric interface in the Kretschmann-Reather configuration using prism coupling technique. Effect of ZnO:N thin film deposited over Prism-Au structure on the SPR reflectance is studied over a wide range of temperature from 300–500 K at 633 nm wavelength. The value of dielectric constant of ZnO:N film obtained by fitting the experimentally obtained data with the theoretically generated SPR curve at the optical frequency is found to increase linearly with temperature. The increase in dielectric constant (4.03 to 4.11) with increase in temperature from 300 K to 500 K indicates a promising application of the system as an efficient low-cost temperature sensor.

On penetrative convection at low Péclet number

1995 ◽  
Vol 292 ◽  
pp. 229-248 ◽  
Author(s):  
John R. Lister
Keyword(s):  
Heat Flux ◽  
Fluid Layer ◽  
Diffusion Problem ◽  
Stable Region ◽  
Base Temperature ◽  
Linear Temperature ◽  
Linear Temperature Gradient ◽  
Wide Range ◽  
Fixed Base ◽  
Interfacial Heat Flux

A new theoretical model is developed for the growth of a convecting fluid layer at the base of a stable, thermally stratified layer when heated from below. The imposed convective heat flux is taken to be comparable to the heat flux conducted down the background gradient so that diffusion ahead of the interface between the convecting and stable layers makes a significant contribution to the interfacial heat flux and to the rate of rise of the interface. Closure of the diffusion problem in the stable region requires the interfacial heat flux to be specified, and it is argued that this is determined by the ability of convective eddies to mix warmed fluid below the interface downwards. The interfacial velocity, which may be positive or negative, is then determined by the joint requirements of continuity of heat flux and temperature. A similarity solution is derived for the case of an initially linear temperature gradient and uniform heating. Solutions are also given for a heat flux that undergoes a step change and for a heat flux determined from a four-thirds power law with a fixed base temperature. Numerical calculations show that the predictions of the model are in good agreement with previously reported experimental measurements. Similar calculations are applicable to a wide range of geophysical problems in which the tendency for diffusive restratification is comparable to that for mixed-layer deepening by entrainment.

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