Local Temperature Monitoring Research Articles

Core–Shell Colloidal Nanocomposites for Local Temperature Monitoring during Photothermal Heating

Core–Shell Colloidal Nanocomposites for Local Temperature Monitoring during Photothermal Heating

Parametric Optothermal Modulation of Carbon Nanooscillator Decorated with Mie Resonant Silicon Particle

AbstractNanomechanical resonators provide a versatile platform for nanoscale mass sensing and force microscopy, as well as for enhancing light‐matter interaction offering unique functionality for optomechanical applications. In this way, discovering new approaches for coupling light with the mechanical degrees of freedom opens the strong desire paths for further developing of nanomechanical technology. Here, the parametric optothermal modulation of hybrid nanomechanical systems consisting of carbon nanowire with a silicon nanoparticle on its top, is reported. The mechanism of the modulation is based on the periodic optical heating of the nanowire and further modulation of the elasticity parameters. Utilizing the silicon nanoparticle provides additional functionality owing to optical absorption enhanced with Mie resonance and the unique feature of optical Raman thermometry enabling optical monitoring of local temperature. It is shown that the parametric mechanism of modulation allows for a significant increase of the optomechanical coupling strength.

Synthesis, crystal structure and NMR-study new mononuclear paramagnetic Er (III) complex based on imine derivatives of thiacalix[4]arene

The synthesis, crystal structure and NMR-study of new paramagnetic Er (III) complex based on imine derivatives of thiacalix[4]arene was carried out. Temperature dependences of the 1H NMR spectra of complex Er(III) and calix[4]arene with N-contained substituents (I) have been analyzed using the line shape analysis, taking into account the temperature variation of paramagnetic chemical shifts, within the frame of the dynamic NMR method. Two kinds of molecular dynamics in I are reported for the CDCl3 solution. The first one conformational dynamics is conditioned by the pinched cone A ↔ pinched cone B interconversion with activation free energy ΔG≠(298 K) = 40 ± 3 kJ/mol (observed at low temperature). The second one dynamics is connected with rearrangements in coordination environment (with ΔG≠(298 K) = 58 ± 3 kJ/mol). Due to substantial temperature dependence of paramagnetic shifts, the complex I can be considered as NMR thermosensor reagent for local temperature monitoring. Owing to the large magnetic moments typical for many Ln-ions and especially high value of magnetic anisotropy for Er cation (III) adopting capped trigonal prismatic geometry of coordination sphere one may expect that 1-Er can potentially exhibit SMM behavior.

Design of a wearable multi-point temperature monitoring system – practical application in waist temperature monitoring

PurposeHuman skin temperature data can provide reference advice for diagnosing many diseases, but current wearable skin temperature monitoring systems have few points and may miss temperature information in critical areas. This paper aims to develop a wearable system that can be used for local temperature monitoring and restore better the actual state of local human temperature by exploring ways to extend more temperature measurement points. This will provide better assistance in developing medical targeting and intelligent clothing.Design/methodology/approachThe temperature measurement system contains modules for temperature monitoring, digital-to-analog conversion and regulated power supply, enabling fast reading of 12 channels of monitoring data. The microprocessor unit is the STM32F407. The instructions and control modes are written in C. The waist area was chosen as the monitoring area because it is susceptible to temperature, and many diseases are associated with skin temperature. Twelve points, including temperature-related acupuncture points and heat-sensitive points, were selected for testing and the data results agreed well with the infrared imaging results.FindingsThe waist is selected as the monitoring object, and an easy-to-wear waist temperature monitoring belt is designed to verify the application value of the system. The development of the system provides reference suggestions for the exploration of multi-point temperature monitoring systems and the integration capabilities of temperature measurement modules in wearable multifunctional systems.Practical implicationsIn addition to waist temperature monitoring, the wearable temperature measurement system developed in this study can also be applied to other body parts. In addition, the system can be efficiently and effectively combined with various garments, making it a useful tool for researching human skin temperature.Originality/valueThe wearable temperature monitoring system designed in this paper extends the number of temperature test points to 12. The number of test points covers as many localized body areas as possible to indeed reproduce the temperature distribution of the human body. In addition, the selection of test points combines medically relevant body points with physiologically relevant heat-sensitive areas, which makes the temperature measurement data more valuable.

Paramagnetic Properties and Moderately RapidConformational Dynamics in the Cobalt(II) Calix[4]arene Complex by NMR.

1H NMR measurements are reported for the CD2Cl2/CDCl3 solutions of the Co(II) calix[4]arenetetraphosphineoxide complex (I). Temperature dependences of the 1H NMR spectra of I have been analyzed using the line shape analysis, taking into account the temperature variation of paramagnetic chemical shifts, within the frame of the dynamic NMR method. Conformational dynamics of the 2:1 Co(II) calix[4]arene complexes was conditioned by the pinched cone ↔pinched cone interconversion of I (with activation Gibbs energy ΔG≠(298K) = 40 ± 3 kJ/mol. Due to substantial temperature dependence of paramagnetic shifts, complex I can be used as model compound for designing an NMR thermosensor reagent for local temperature monitoring.

Optomagnetic nanofluids for controlled brain hyperthermia: a critical study.

Optomagnetic nanofluids (OMNFs) are colloidal dispersions of nanoparticles (NPs) with combined magnetic and optical properties. They are especially appealing in biomedicine since they can be used as minimally invasive platforms for controlled hyperthermia treatment of otherwise difficultly accessible tumors such as intracranial ones. On the one hand, magnetic NPs act as heating mediators when subjected to alternating magnetic fields or light irradiation. On the other hand, suitably tailored luminescent NPs can provide a precise and remote thermal readout in real time. The combination of heating and thermometric properties allows, in principle, to precisely monitor the increase in the temperature of brain tumors up to the therapeutic level, without causing undesired collateral damage. In this work we demonstrate that this view is an oversimplification since it ignores the presence of relevant interactions between magnetic (γ-Fe2O3 nanoflowers) and luminescent nanoparticles (Ag2S NPs) that result in a detrimental alteration of their physicochemical properties. The magnitude of such interactions depends on the interparticle distance and on the surface properties of nanoparticles. Experiments performed in mouse brains (phantoms and ex vivo) revealed that OMNFs cannot induce relevant heating under alternating magnetic fields and fail to provide reliable temperature reading. In contrast, we demonstrate that the use of luminescent nanofluids (containing only Ag2S NPs acting as both photothermal agents and nanothermometers) stands out as a better alternative for thermally monitored hyperthermia treatment of brain tumors in small animal models.

Anti-Stokes Raman Scattering of Single Carbyne Chains.

We investigate the anti-Stokes Raman scattering of single carbyne chains confined inside double-walled carbon nanotubes. Individual chains are identified using tip-enhanced Raman scattering (TERS) and heated by resonant excitation with varying laser powers. We study the temperature dependence of carbyne's Raman spectrum and quantify the laser-induced heating based on the anti-Stokes/Stokes ratio. Due to its molecular size and its large Raman cross section, carbyne holds great promise for local temperature monitoring, with potential applications ranging from nanoelectronics to biology.

Electrode-Integrated Textile-Based Sensors for In Situ Temperature and Relative Humidity Monitoring in Electrochemical Cells.

Temperature and humidity measurements in electrochemical energy devices are essential for maximizing their overall performance under different operating conditions and avoiding hazardous consequences that may arise from the malfunction of these systems. Using sensors for in situ measurements of temperature and relative humidity (RH) is a promising approach for continuous monitoring and management of electrochemical power sources. Here, we report on the feasibility of using thread-based sensors for in situ measurements of temperature and RH in proton exchange membrane fuel cells (PEMFCs) as an example of electrochemical energy devices. Commodity threads are low-cost and flexible materials that hold great promise for the creation of complex three-dimensional (3D) circuits using well-established textile methods such as weaving, braiding, and embroidering. Ex situ and in situ characterization show that threads can be introduced in the gas diffusion layer (GDL) structure to inscribe water highways within the GDL with minimal impact on the GDL microstructure and transport properties. Fluorinated ethylene propylene (FEP) is coated on thread-based sensors to decouple the response to temperature and humidity; the resulting threads achieve a linear change of resistance with temperature (−0.31%/°C), while RH is monitored with a second thread coated with poly(dimethylsiloxane) (PDMS). The combination of both threads allows for minimally invasive and dynamically responsive monitoring of local temperature and RH within the electrode of PEMFCs.

Pitfalls in Monitoring Mitochondrial Temperature Using Charged Thermosensitive Fluorophores

Mitochondria are the source of internal heat which influences all cellular processes. Hence, monitoring mitochondrial temperature provides a unique insight into cell physiology. Using a thermosensitive fluorescent probe MitoThermo Yellow (MTY), we have shown recently that mitochondria within human cells are maintained at close to 50 °C when active, increasing their temperature locally by about 10 °C. Initially reported in the HEK293 cell line, we confirmed this finding in the HeLa cell line. Delving deeper, using MTY and MTX (MitoThermo X), a modified version of MTY, we unraveled some caveats related to the nature of these charged fluorophores. While enabling the assessment of mitochondrial temperature in HEK and HeLa cell lines, the reactivity of MTY to membrane potential variations in human primary skin fibroblasts precluded local temperature monitoring in these cells. Chemical modification of MTY into MTX did not result in a temperature probe unresponsive to membrane potential variations that could be universally used in any cell type to determine mitochondrial temperature. Thus, the cell-type dependence of MTY in measuring mitochondrial temperature, which is likely due to the variable binding of this dye to specific internal mitochondrial components, should imply cautiousness while using these nanothermometers for mitochondrial temperature analysis.

Tm-DOTA as responsive relaxation and shift probe for NMR local temperature monitoring at high magnetic fields

Paramagnetic properties of Na[Tm(DOTA)] complex were investigated by 1H NMR under magnetic fields of 4.70, 11.75, 14.09 and 18.79 T. The Curie-Spin contribution to the transverse relaxation rates is found to be predominant at low temperatures (below 300 K). The experimental paramagnetic LIS values are well fitted by linear dependence on reciprocal temperature and have height temperature sensitivity of 1.9 ppm/K at 277 K. The obtained results indicate that the coordination compound Na[Tm(DOTA)] is the most shifting and also sensitive relaxation paramagnetic probe for in situ monitoring of local temperature in liquid media. At elevated temperature (above 310 K) it wasobserved a molecular dynamics related to intramolecular interconversion between two isomers: the square-anti-prismatic (SAP) and the twisted-square-anti-prismatic (TSAP) conformers. The free energy of activation of SAP-TSAP interconversion is found to be 65 ± 2 kJ mol−1.

Assessment of potential heat flux overload of target and first wall components in Wendelstein 7-X finite-beta magnetic configurations and choice of locations for temperature monitoring

Abstract Within the framework of R&D activities on the Wendelstein 7-X (W7-X) stellarator machine, the assessment of heat loads onto the plasma facing components (PFCs) is an important aspect. So far, W7-X was operated in short pulses without water cooling of the PFCs. Presently, the device is being prepared for future operation phases with water cooling. The target plates, which receive the highest heat loads, are monitored by a thermography system. The rest of the first wall (heat shield) is not designed to receive convective particle loads, and it is in part poorly monitored by the infrared cameras. Recent studies have shown that for many plasma configurations there are locations on the heat shield which do receive significant convective heat flux. This is in particular true for the heat shields adjacent to the target plates (called baffles) and for configurations with finite plasma pressure, where the magnetic configuration is modified by plasma currents. On the other side, the heat flux limit to the baffle tiles had to be reduced from 0.50 to 0.25 MW/m2. In this work an evaluation of the heat flux to targets and baffles in plasma configurations with finite plasma pressure is presented. To this end, Field Line Diffusion (FLD) calculations have been performed to obtain the heat load pattern distributions for the considered magnetic configurations. The results have been assessed statistically to achieve a measure of certainty in the prediction of an overload in a certain location. The possibility of overloads onto the baffles due to plasma radiation has also been investigated. The results of the entire analysis show that local temperature monitoring by thermocouples in a rather limited number of locations will be sufficient to avoid heat flux overloads of the baffles and heat shields in all magnetic configurations considered.

Fluorescent Polymer-MoS2-Embedded Microgels for Photothermal Heating and Colorimetric Monitoring.

Photothermal heating with accurate monitoring of local temperature in complex biological fluids is crucial for therapeutic accuracy. Herein, photothermal microgels are developed to heat microscopic volumes through photothermal conversion and report the local temperature with a colorimetric response. The microgels consist of poly(ethylene glycol)-based hydrogels, which integrate temperature-responsive block-copolymer-grafted MoS2 nanosheets (BCP-grafted MoS2 NSs). The MoS2 NSs are used as a fluorescence quencher as well as an efficient photothermal agent, with their surface decorated with three distinct temperature-responsive BCPs containing blue-, green-, and red-fluorescent dyes. Upon irradiation of near-infrared light, MoS2 NSs convert the radiation into heat, and the BCPs change their conformation depending on the local temperature, selectively activating Förster resonance energy transfer of the three dyes. The use of three distinct BCPs and dyes enables the measurement of temperature in a wide range (i.e., from 25 to 50 °C). Importantly, the hydrogel matrix excludes molecules larger than the limiting mesh size so that BCP-grafted MoS2 NSs remain free from contamination against large adhesive proteins such as albumin, thus maintaining their sensitivity even in complex fluids.

Innovation in Textile Electrode of Electrochemical Devices: Water Transport and Thread-Based Temperature and Humidity Sensors

Wearable health monitoring utilizing advances in textile technologies has already been demonstrated for transport of biomarkers and physiological sensing. These advances can potentially be translated to textile electrodes of electrochemical devices to allow managing reactants and by-products transport and for monitoring environmental parameters. Herein, a wicking properties and flexibility of threads are used (1) to control transport of water (by-product) within a textile gas diffusion layer (GDL) of the electrode of polymer electrolyte membrane fuel cells (PEMFCs), and (2) to develop thread-based sensors for local temperature and humidity monitoring.By means of ex-situ and in-situ characterizations, it was found that the threads can be introduced in the GDL structure to inscribe water highways within the GDL with minimal impact on GDL microstructure (i.e. porosity, porosity distributions) and transport properties (i.e. permeability, diffusivity and conductivity). Furthermore, a low-cost procedure was developed to transform a commodity thread into temperature and humidity sensors by dip-coating the thread with carbon nanotubes (CNTs) ink. The resistance of CNT coated threads is responsive to both parameters. In this work, the response to humidity was cancelled by coating fluorinated ethylene propylene (FEP) on top of the CNT coated thread to develop a temperature sensor independent of humidity. In addition, a second thread was coated with polydimethylsiloxane (PDMS) to monitor the relative humidity (RH).Thread-based sensors were characterized in an environmental chamber simulating environmental conditions in an operating fuel cell. A linear change of resistance with increasing temperature (~-0.31 %/T) was achieved for the temperature sensor, and the resistance of the thread coated with PDMS showed more sensitivity in high humidity regions (RH > 60%) and followed a quadratic function of RH. The thread-based temperature sensor capability was assessed via ex-situ experiments, and showed rapid response to change of temperature, and also the ability to map temperature in non-uniform temperature distributions. The combinations of both threads can allow simultaneous monitoring of local temperature and RH in the textile GDL of PEMFCs. This work enables local sensing and monitoring within textile electrodes without compromising the performance of PEMFCs.

Research on Local Humidity Environment of Ground Parking Aircraft

Local humidity and temperature monitoring of ground parking aircraft were carried out in this study. Changes in the humidity of different bays and the relationship between local humidity and local temperature were investigated. Moreover, the concept as well as a method of calculating the humidity characteristic coefficient (HCC) were put forward, and two models of aircraft local humidity were established using the humidity and temperature of the thermometer shelter as arguments. Furthermore, bays of an airplane were divided into three groups according to differences in local humidity, and the range of the HCC of each group were determined. The results suggest that the rates of change of local humidity and local temperature are negatively correlated, moreover, the theoretical model shows a linear relationship between humidity and temperature, with a negative slope suggesting changes in humidity are inversely proportional to temperature. The ratio of the local environment slope to the external environment slope has a constant value. Finally, bay sealing and temperature features were found to significantly affect local humidity, and average deviations between the monitored humidity and humidity values predicted using the two temperature models were all less than, or equal to, 7.3% relative humidity.

Temperature Effects on the Magnetization and Magnetoimpedance in Ferromagnetic Glass-Covered microwires

The effect of temperature on static and dynamic magnetization in Co-based amorphous microwires was investigated with the aim of potential applications in miniature temperature sensors. The wires of two compositions with different magnetostriction and Curie temperature in glass-cover and after removing the glass layer demonstrated very different temperature behaviour of the magnetization loops and magnetoimpedance. The mechanisms of the temperature effects are related to the residual stress distribution due to fast solidification, the difference in thermal expansion coefficient of metal and glass and the proximity to the Curie temperature. The interplay of these factors may result in a very strong temperature dependence of magnetoimpedance in a moderate temperature range (room temperature −373K). Such elements may be incorporated in various composite materials for a local temperature monitoring.

Simultaneous in vivo recording of local brain temperature and electrophysiological signals with a novel neural probe

Objective. Temperature is an important factor for neural function both in normal and pathological states, nevertheless, simultaneous monitoring of local brain temperature and neuronal activity has not yet been undertaken. Approach. In our work, we propose an implantable, calibrated multimodal biosensor that facilitates the complex investigation of thermal changes in both cortical and deep brain regions, which records multiunit activity of neuronal populations in mice. The fabricated neural probe contains four electrical recording sites and a platinum temperature sensor filament integrated on the same probe shaft within a distance of 30 µm from the closest recording site. The feasibility of the simultaneous functionality is presented in in vivo studies. The probe was tested in the thalamus of anesthetized mice while manipulating the core temperature of the animals. Main results. We obtained multiunit and local field recordings along with measurement of local brain temperature with accuracy of 0.14 °C. Brain temperature generally followed core body temperature, but also showed superimposed fluctuations corresponding to epochs of increased local neural activity. With the application of higher currents, we increased the local temperature by several degrees without observable tissue damage between 34–39 °C. Significance. The proposed multifunctional tool is envisioned to broaden our knowledge on the role of the thermal modulation of neuronal activity in both cortical and deeper brain regions.

Integrated microsensor for real-time microscopic monitoring of local temperature, voltage and current inside lithium ion battery

The lithium ion battery overcharge may cause thermal runaway, even hazardous conditions like explosion, resulting in safety problem. High charge/discharge rate is required for 3C products like smart phone and tablet PC and electric vehicles, but it will cause steep rise of internal temperature of lithium ion battery, unstable voltage and current and safety problem.This study used micro-electro-mechanical systems (MEMS) to develop an integrated microsensor of temperature, voltage and current microsensors, embedded in the lithium ion battery for real-time microscopic monitoring of internal temperature, voltage and current. This integrated microsensor is characterized by quick response, real-time measurement and batch manufacturing.

A 30 $\mu\text{W}$ Remotely Powered Local Temperature Monitoring Implantable System.

An implantable local temperature monitoring system for a laboratory mouse is presented. Magnetic coupling is used to remotely power the passive implant. The temperatures of two local points are monitored by thermistors. A low-power readout circuit is implemented by directly amplifying and resolving the sensor response in the time domain. A free-running oscillator operating at 868 MHz transmits the sensor data to the base station. The average power dissipation of the implant is decreased by time interleaving between the sensor readout and the data communication. The power transfer to the implant is also time interleaved with other operations to avoid interference with data communication. A voltage regulation loop for the implant based on controlling the duration of powering the base station power amplifier is also described. A prototype chip is implemented in 0.18 [Formula: see text] CMOS. The implant requires average RF power of 29.5 [Formula: see text] for operation and is capable of measuring two thermistors with accuracy of ±0.05 °C.

Local cell temperature monitoring for aluminum shell lithium-ion battery based on electrical resistance tomography

This paper presents an approach for the local the cell temperature monitoring of an aluminum shell lithium-ion battery cell by electrical resistance tomography, which has a great potential to analyze the correlation of apparent resistivity, local cell temperature and residual capacity. To determine this correlation, a flexible sensor was first designed, and the Wenner configuration was applied in the measurements. The investigated temperatures ranged from −20°C to 70°C. The results showed that the apparent resistivity had an exponentially increasing trend as the temperature increased. The effect of the residual capacity was further investigated. It is found that a lower residual capacity resulted in a lower apparent resistivity, which intensified as the temperature decreased. A comprehensive equation was developed to determine the local cell temperatures. Images of the apparent resistivity distribution under cell discharge further revealed the feasibility of the method. Finally, the proposed equation was applied to evaluate the cell core temperature which was compared with the surface temperatures from external sensors.

Skin temperature measurements by infrared thermography during running exercise

The thermal interaction of human body and the environment during running activity is an important mechanism that may affect the athletic performance. Skin temperature plays the fundamental role of regulating the heat exchange by convection, radiation and evaporation. In this study, the skin temperature response to running exercise has been tested by infrared thermographic imaging, a highly reliable method for the real time, non-invasive monitoring of local cutaneous temperature over the body surface. Measurements performed for long-distance runners showed a fall in skin temperature during the initial stage of running exercise, regardless of the type of work (overground or treadmill) and environmental (outdoor or indoor) conditions. It is argued that this skin temperature decrease is associated with the cutaneous vasoconstrictor response to exercise. A continuous increase in load intensity (as occurs during an incremental treadmill exercise) may produce further reductions in skin temperature; conversely, a constant load running exercise is likely to promote the attainment of a relative minimum of skin temperature, followed by a gradual little rise over time related to thermoregulatory vasodilation.