Thermistor Temperature Sensors Research Articles

Printed temperature sensor based on self-doped conducting polymers

The printing of an efficient thermistor temperature sensor by using self-doped conducting polymers has been achieved. The use of a water-soluble polymer as the active material allows printing and processing in green solvents. The sensor showed a good sensitivity to temperature variations, with a temperature coefficient of resistance of −1.3%. The sensor also exhibited a better stability and reversibility towards humidity compared to the state-of-the-art poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS).

A Thermocycler Using a Chip Resistor Heater and a Glass Microchip for a Portable and Rapid Microchip-Based PCR Device.

This study proposes a rapid and inexpensive thermocycler that enables rapid heating of samples using a thin glass chip and a cheap chip resistor to overcome the on-site diagnostic limitations of polymerase chain reaction (PCR). Microchip PCR devices have emerged to miniaturize conventional PCR systems and reduce operation time and cost. In general, PCR microchips require a thin-film heater fabricated through a semiconductor process, which is a complicated process, resulting in high costs. Therefore, this investigation substituted a general chip resistor for a thin-film heater. The proposed thermocycler consists of a compact glass microchip of 12.5 mm × 12.5 mm × 2 mm that could hold a 2 μL PCR sample and a surface-mounted chip resistor of 6432 size (6.4 mm × 3.2 mm). Improving heat transfer from the chip resistor heater to the PCR reaction chamber in the microchip was accomplished via the design and fabrication of a three-dimensional chip structure using selective laser-induced etching, a rapid prototyping technique that allowed to be embedded. The fabricated PCR microchip was combined with a thermistor temperature sensor, a blower fan, and a microcontroller. The assembled thermocycler could heat the sample at a maximum rate of 28.8 °C/s per second. When compared with a commercially available PCR apparatus running the same PCR protocol, the total PCR operating time with a DNA sample was reduced by about 20%.

Variation of annealing temperature with excess of NaOH concentration on Ag2S synthesis from argentometry titration waste as NTC thermistor

Utilization of AgCl from argentometric titration waste can be done by converting AgCl into silver sulfide (Ag2S) semiconductor. The variation of annealing temperature in Ag2S synthesis affects the properties and quality of the Ag2S semiconductor. Silver sulfide semiconductor can be applied as a NTC (negative temperature-coefficient) thermistor temperature sensor. The NTC thermistor shows a decrease in resistance with increasing temperature. This study aims to synthesize Ag2S from argentometric titration waste with excess NaOH concentration and variations in annealing temperature as a temperature sensor for NTC thermistors. Ag2S was synthesized using thiourea reagent in alkaline NaOH medium. The synthesized silver sulfide was then annealed at various temperatures of 100, 200 and 300 °C for 30 min. Ag2S was then characterized using Thermo Gravimetrical Analysis (TGA), X-Ray Diffraction (XRD) and UV–Vis Diffuse Reflectance Spectroscopy (UV–Vis DRS). The results of TGA analysis showed that Ag2S at a temperature of 836 °C had decomposed into Ag and S2. From the XRD characterization results showed the presence of Ag2S at 2θ peaks of 22; 29; 31; 38 and 41°. Ag2S crystal size increases with increasing annealing temperature, which are 37.04; 39.55 and 41.68 nm. The results of UV–Vis DRS characterization showed that the Ag2S band gap value decreased with increasing annealing temperature, which were 0.96; 0.94; and 0.92 eV. The resistance measurement results show that the Ag2S semiconductor at annealing temperature of 300 °C is an NTC thermistor with good electrical quality, has a sensitivity of 6.85% and a thermistor constant of 6087 K.

Recent Patents for Thermistor Temperature Sensor

Background: The collection of temperature is very important in life. Thermistor temperature sensors are an important part of the temperature acquisition system. Thermistor temperature sensors can convert the temperature signal into an electrical signal for output. Due to the different application fields and technical requirements, the shape, function and structure of thermistor temperature sensors are very different. Objective: The purpose of this study is to summarize and analyze the advantages and disadvantages of various devices from a large number of documents and patents. Methods: In this paper, the patents and the latest research of thermistor temperature sensors are reviewed. Results: By summarizing the characteristics of a large number of thermistor temperature sensors and analyzing the problems, the development of thermistor temperature sensors is expected. Conclusion: Thermistor temperature sensors are widely used. Therefore, it is necessary to carry out special structural design and technical research for thermistor temperature sensors in different application fields. At the same time, with the development of technology, intelligent sensors and multi-functional sensors are an inevitable development trend.

Investigation of temperature effects of a 635 nm low power solid-state diode laser on agar phantom using two different thermocouples

It has been reported in the literature that low-level laser therapy is non-invasive, has no obvious side effects, has a very low cost, and is an effective and new treatment technique. It has been published that low-level laser therapy works at between 1 mW and 500 mW power, and between 390 nm and 1100 nm wavelengths without causing harmful heat to the human body, and in this technique, a high intensity, monochromatic, narrow-band light source is applied locally. It is also stated in this technique that instead of producing a thermal effect, photochemical reactions in the cells are stimulated, allowing the tissues to heal themselves. In this study, the temperature effects of a solid-state diode laser with a maximum operating power of 400 mW on the Agar phantom, which is an artificial tissue-mimicking material, were investigated using two different thermocouples for different distances and durations. In the study, Agar phantom as artificial tissue-mimicking material, red solid-state diode laser with 635 nm wavelength as a laser source, T-type ultra-thin thermocouple, and NTC type thermistor temperature sensor were used. The experiments were carried out separately for periods of 20 s, 40 s, 60 s, and 80 s time intervals. In this article, the results of temperature measurement studies both within the agar phantom by using two different thermocouples and two different temperature measurement systems, and on the surface of the agar phantom by using an infrared thermal camera were reported after realizing the characterization of the phantom. Besides, the laser used was also evaluated for the eye and skin contact within the concept of maximum permissible exposure (MEP).

Metrological Support of Medical Drillings at the Lateral Skull Base

Abstract For minimally invasive drilling processes, the temperature development in the drilling ground is of crucial importance for patient safety. To monitor the temperature during drilling, a drill prototype was developed by BREDEMANN ET AL. which can record the drill temperature in parallel to the process and in real time. The measurement principle of the thermistor (temperature sensor) integrated in the drill could be validated. [1] The prototype must be refined for use in the operating room, as the drill does not yet meet all the medical requirements that need to be fulfilled. In further development, the recorded temperature data in particular must be processed and communicated to the surgeon in order to provide added value for the surgical procedure.

Cofiring of LTCC multilayer assemblies with integrated NTC thermistor temperature sensor layers

We have studied the integration of Ni–Co–Zn–Mn spinel NTC thermistor layers into LTCC multilayer modules. Sintering of the cubic spinel Ni0.5Co0.5Zn0.75Mn1.25O4 with addition of 3 wt% Bi2O3 additive at 900 °C resulted in samples with 96% density and with good electrical performance. Thermistor spinel tapes, fabricated using doctor blade tape casting, were stacked with layers of a commercially available low-k dielectric LTCC tape, and cofired at 900 °C. Free or constrained cofiring did not give crack-free multilayer samples. Thermistor layers were then integrated combining the commercial LTCC tape with a Zn titanate-based tape in one multilayer laminate, and error-free multilayer samples with a room-temperature resistivity of ρ298 = (2,9 ± 0.08) kΩcm and a thermistor constant of B = (4280 ± 200) K were obtained. This demonstrates the possibility of cofiring of functional ceramic and low-k LTCC tapes and shows the potential of NTC spinel thermistor layers as temperature sensors integrated in complex LTCC multilayer architectures.

Study on novel temperature sensor based on amorphous carbon film

In this study, a new type of thermistor temperature sensor was developed. The sensing materials was amorphous carbon (a-C) film prepared using electron cyclotron resonance (ECR) plasma processing system under low energy electron irradiation sputtering. The nanostructure of a-C film was observed by transmission electron microscope (TEM), the atomic bonding and carbon hybridisation condition was analysed by Raman spectra and X-ray photoelectron spectroscopy (XPS), respectively. The linearity of temperature-resistance curve of this kind of a-C film was very good in certain temperature range, with high temperature coefficient of resistance (TCR). The a-C film by 50 eV electron irradiation can measure larger temperature range from –75°C to 155°C, with good repeatability. The working temperature range of a-C film by 100 eV electron irradiation was much smaller, but TCR absolute value of this film was higher. It can be concluded that the lower sp2/sp3, the better linearity of temperature-resistance curve, the lower TCR absolute value in certain working temperature range. The research shows that this kind of a-C film temperature sensor has good linearity and repeatability; also it can be integrated with other MEMS sensor simply.

Use of Thermistor Temperature Sensors for Cyber-Physical System Security.

The last few decades have seen a large proliferation in the prevalence of cyber-physical systems. This has been especially highlighted by the explosive growth in the number of Internet of Things (IoT) devices. Unfortunately, the increasing prevalence of these devices has begun to draw the attention of malicious entities which exploit them for their own gain. What makes these devices especially attractive is the various resource constraints present in these devices that make it difficult to add standard security features. Therefore, one intriguing research direction is creating security solutions out of already present components such as sensors. Physically Unclonable Functions (PUFs) are one potential solution that use intrinsic variations of the device manufacturing process for provisioning security. In this work, we propose a novel weak PUF design using thermistor temperature sensors. Our design uses the differences in resistance variation between thermistors in response to temperature change. To generate a PUF that is reliable across a range of temperatures, we use a response-generation algorithm that helps mitigate the effects of temperature variation on the thermistors. We tested the performance of our proposed design across a range of environmental operating conditions. From this we were able to evaluate the reliability of the proposed PUF with respect to variations in temperature and humidity. We also evaluated the PUF’s uniqueness using Monte Carlo simulations.

STANDARD ENTHALPY OF FORMATION OF PARAOXYPHENYLGLYCINE AND PRODUCTS OF ITS DISSOCIATION IN AQUEOUS SOLUTION

Depending on the chemical nature of the side radicals, amino acids can be divided into aromatic and aliphatic, as well as amino acids, the presence of non-polar or polar functional groups in the side radicals. Since the characteristics of individual amino acids in the protein are determined by the nature (physico-chemical properties) of their side radicals, which are in a hydrated state. It is also extremely important to study the thermodynamic characteristics of the hydration of the side radicals of amino acids of different chemical nature. To obtain empirical correlations that would establish a connection between the thermodynamic parameters of the interaction of dissolved compounds with the solvent and the size of the molecules to be dissolved (having different physico-chemical nature), it is necessary to accumulate a sufficient amount of experimental data on the heats of dissolution of amino acids. This will allow you to calculate the contribution of intermolecular interactions for different groups of molecules. By potentiometric method the protolytic equilibria in aqueous solutions of paraoxyphenylglycine were investigated. The measurements were carried out at a temperature of 298.15 K and an ionic strength of 0.25 (against the background of potassium nitrate). Calorimetric measurements were carried out on an ampoule calorimeter, with an isothermal shell, a thermistor temperature sensor KMT-14, and an automatic record of the temperature-time curve. The operation of the unit was verified by the integral enthalpy of dissolution in water of crystalline potassium chloride. The agreement between the experimental enthalpies of dissolution of KCl (cr) with the most reliable literature data indicates that there are no systematic errors in the calorimetric system. Samples of para-oxyphenylglycine were weighed on a VLP-200 scale with an accuracy of 2∙10-4 g. The confidence interval of the mean value of ΔH was calculated with a probability of 0.95. A paraxyphenylglycine preparation, «Reachim», was used in the work. The reagent was used without further purification. The RRSU program was used to determine the equilibrium composition of the solutions. Standard enthalpies of combustion and formation of crystalline paraxyphenylglycine were calculated. Thermal effects of dissolution of crystalline paraxyphenylglycine in water and in solutions of potassium hydroxide at 298.15 K were determined with the direct calorimetric method. Standard enthalpies of formation of amino acids and products of their dissociation in aqueous solution were calculated.

A method of direct diagnostics of thermoresistive temperature sensors in vehicle

The article discusses thermistor temperature sensors used in automotive vehicles. The characteristic types R=f(T) of thermoresistors as well as their technical and operational parameters are presented. The applications of particular types of thermoresistors in temperature measurements in automotive vehicles are discussed. On the example of the coolant temperature sensors diagnostics is presented. The test results and conclusion regarding the tested sensor diagnostics is presented. The test result and conclusions regarding the tested sensors are presented.

A High-Precision CMOS Temperature Sensor with Thermistor Linear Calibration in the (-5 °C, 120 °C) Temperature Range.

A high-precision Complementary Metal-Oxide-Semiconductor (CMOS) temperature sensor for (−5 °C, 120 °C) temperature range is designed and analyzed in this investigation. The proposed design is featured with a temperature range selection circuit so that the thermistor linear circuit automatically switches to a corresponding calibration loop in light of the temperature range besides the analysis of the calibration method. It resolves the problem that the temperature range of a single thermistor temperature sensor is too small. Notably, the output of the proposed design also attains a high linearity. The measurement results in a thermal chamber justifying that the output voltage is 1.96 V to 4.15 V, the maximum linearity error ≤1.4%, and the worst temperature error ≤1.1 °C in the temperature range of −5 °C to 120 °C.

STANDARD FORMATION ENTHALPIES OF HYDROXYETHYLIDENEDIPHOSPHONIC ACID AND PRODUCTS OF ITS DISSOCIATION IN AQUEOUS SOLUTION

This study aimed the measuring the standard enthalpies of formation of hydroxyethylidenediphosphonic acid and the products of its dissociation in aqueous solutions at 298.15 K. In the literature there is a large amount of data on the constants of stepwise dissociation of the acid. The works were done at different temperatures and the values of the ionic strength of the solution on the background of the different nature of the supporting electrolytes. In order to compare the values of the constants of stepwise dissociation of the acid, obtained by different authors, we recalculated the values of рK1, рK2, рK3, рК4, рК5 at zero ionic strength by the Davies equation. The most probable values of thermodynamic constants of dissociation of hydroxyethylidenediphosphonic acid were the following: рК10 = 1.7±0.03; рК20 = 2.47±0.05; рК30 = 7.78±0.05; рК40 = 10.29±0.05 and pK50 = 11.13±0.05. Calorimetric measurements were performed on an ampoule calorimeter equipped with an isothermal shell and a KMT-14 thermistor temperature sensor, and the automatic recording the temperature changes over time. The operation of installation was verified with the integral enthalpies of dissolution in water of crystalline potassium chloride and was considered suitable for measurements, if certain it ∆solН298.15 (KCl ∞ H2O)=17.234± 0.018 kJ/mol, corresponding to the standard SRM 1655NBS. The heat value of the calorimeter water was 87±12 Дж/mol virtually coincided with the thermal value of the calorimeter for potassium hydroxide. The volume of the calorimetric liquid was 43.12 ml. The hydroxyethylidenediphosphonic acid samples were weighed on a VLR-200 balance with 2∙10-4 g accuracy. The confidence range of the average ΔН value was determined at 0.95 probability. The equilibrium compositions of solutions were calculated using RRSU software. The standard enthalpies of formation of hydroxyethylidenediphosphonic acid and the products of its dissociation in aqueous solutions were calculated.Forcitation:Lytkin A.I., Chernikov V.V., Krutova O.N., Skvortsov I.A. Standard formation enthalpies of hydroxyethylidenediphosphonic acid and products of its dissociation in aqueous solution. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2018. V. 61. N 4-5. P. 37-42

더미스터 온도센서를 이용한 나노유체의 대류열전달계수 측정 장치

더미스터 온도센서를 이용한 나노유체의 대류열전달계수 측정 장치

Intelligent Machine Tool – A Thermal Diagnostic System for a CNC Pretensioned Ball Screw

The paper presents a compensation system of thermal deformation for conventional feed axes applied in CNC machine tools allowing for an effective reduction in the impact of heat generated during its operation on the positioning accuracy of the axis. The result has been achieved by equipping feed screws with thermistor temperature sensors. Wiring sensors was led out through an axial bore in the screw and through a rotating electrical connector to an acquisition device coupled with the control system of the CNC machine. An algorithm based on neural networks was implemented in the machine control system, which allows for the online calculation and compensation of heat deformation of feed screws. The algorithm takes into account a variation of thermal deformation values as a function of the table position and the current distribution of the temperature field of the screw and machine. The paper presents a user-friendly method for implementing algorithms containing neural networks in the machine control system. The proposed compensation method has been verified by measuring the linear accuracy of the feed axis positioning. The obtained results confirm the effectiveness of the proposed method in reducing the impact of thermal deformation errors on the positioning accuracy of the axis in CNC machine tools.

Hardware Design of Nature Gas Engine ECU Based on Single Chip

Gas supply method plays an important role in engine performance for natural gas engines (NGE). In order to overcome the low charging efficiency of pre-mixed fuel gas supply method the multi-point injection (MPI) gas engine controller hardware system is designed in this paper. For the nature gas engine controller the main controller is selected as the microcontroller MC9S12XSl28, then the circuitry for semiconductor piezoelectric air pressure sensor, potentiometer throttle position, thermistor temperature sensor, a magnetic-electric sensor for detecting the top dead center (TDC) and simulating engine speed are designed. What have done above is the base of software design. Key Words: nature gas engine; controller; hardware design

WE-G-17A-06: A Water Calorimeter for Use in MRI Linacs

Purpose: At VSL, Dutch Metrology Institute, a new water calorimeter was developed with the purpose to replace the existing primary standard for absorbed dose to water in the Netherlands. The new water calorimeter is designed to be operable in medium- to high energy photon beams, electrons, protons as well as MRI integrated linear accelerators. VSL has operated a water calorimeter since 2001. This calorimeter formed the basis for the NCS-18 dosimetry protocol, which is commonly applied by medical physicists in the Netherlands and Belgium. Methods: The unit Gray is the unit of interest for measurement of the absorbed dose to water. Water calorimetry involves the measurement of a small temperature rise (0.24 mK/Gy) with an uncertainty of less than 1 μK/Gy at a temperature of 4 °C. Using extensive multi-physics simulations the new calorimeter's thermal performance was simulated before it was constructed at the end of 2013. With the advent of radiotherapy treatment units incorporating MR imaging the performance of the thermistor temperature sensors were characterized in a 1.5 T magnetic field. Results: A change of thermistor resistance was observed of less than 0.004% as a Result of the magneto-resistance effect in a 1.5 T magnetic field. Although a magneto-resistance effect was detectable, the effect on the temperature response in the water calorimeter was found to be negligible. Conclusion: With the realization of the new calorimeter operable in MRI linacs and designed for use in a variety of beam modalities, VSL is ready for accurate dosimetry in new advanced radiotherapy modalities. Due to the small form factor the calorimeter can be used on location in the actual therapy beam inside a 68 cm linac bore. This work was supported by EMRP grant HLT06. The EMRP is jointly funded by the EMRP participating countries within EURAMET and the European Union.

Investigation of Stability and Reliability of the Patient's Wireless Temperature Monitoring Device

Currently, wireless radio frequency (RF) communication and Wireless Sensor Network (WSN) has shifted its trend on human or item tracking capability to real time monitoring capability especially in healthcare industry. Monitoring patient's condition is one of the crucial tasks in any hospital to ensure patients are in good and stable condition. Efforts have been made by many researchers to use WSN to measure temperature, heart rate, oxygen saturation, respiratory rate and etc. to monitor patient's condition remotely in hospitals. This research focuses on integrating a temperature sensor to a wireless transceiver Zigbee network and is used to measure patient's body temperature from remote location (nurse's workstation. Few thermistor temperature sensors were used to determine reliability and their reading were compared against thermometer and the one with an accurate and stable reading was chosen. Zigbee network or accurately known as IEEE 802.15.4/Zigbee is known to be a low power consumption device with better transmission range, higher network flexibility and large number of nodes. Through the experimentation, Zigbee network is proven capable to provide stability in data transmission at longer range at different temperature environment.

Network Monitoring System of Multipoint Temperature Collection and Control

The temperature monitoring control is the most basic data parameters of the daily life and industrial production; it also has very important significance in multi-point temperature collection, accurate measurement and control monitoring. Therefore, this paper was based on SCM to deal with the temperature information data, design the multipoint temperature monitoring system, design the function of multipoint temperature collection and control network monitor system and main program, subroutine and so on. At the same time, this paper expounded the design methods of temperature acquisition, calculation and display. It used the thermistor temperature sensor to measure real-time temperature of the periphery environment, and voltage change that transformed from the measured temperature was transmitted to ADE0708 converter for modulus conversion, and the number was input to the serial interface and dealt with computer software to output conversion by SCM, digital tube was displayed in digital sections, it was the real-time temperature value. According to the converter channel port it could set output driving control signal, the display light had status indication and adjustment and control.

Acceleration of applied voltage on metallic ion migration of wires in NTC thermistor temperature sensors

The research on NTC (Negative Temperature Coefficient) thermistors often used in temperature sensors has usually focused on performance, and almost no research have been previously done with the focus on reliability, even though field failures of NTC thermistors caused by ion migration are increasing. Therefore, this paper focuses on ion migration between wires, which has a close relationship with field failures of NTC thermistors by measuring the time when ion migration occurs according to different distances between wires and the applied voltage, and quantitatively analyzing the mechanism of ion migration occurrence, acceleration and correlation with ion migration due to applied voltage. Ion migrations between Cu wires occur because of the absorption and condensation of water. Also, due to the inherently brittle characteristics of the dendrite, repeated separation and coalescence were observed. The results of estimating the time of ion migration according to the applied voltage using both Weibull distribution and the same shape parameter showed a good match with the inverse power model, and an index and a specific parameter expressing the sensitivity of ion migration occurrence could be extracted by analysis.