In situ temperature measurement of vapor based on atomic speed selection

We demonstrate an experimental method for the in situ temperature measurement of atomic vapor using the saturated absorption spectrum. By separately manipulating the frequency of the pump and probe beams, the position of the crossover peaks can move along the spectrum. Different velocity classes of atoms contribute to the crossover during the movement. We study the relationship between the intensity change of peaks and vapor temperature. Our experimental result around room temperature shows a deviation of less than 0.3 K. Compared with traditional thermometry using absorption spectroscopy, higher accuracy can theoretically be achieved with real-time thermometry.

Revamping design of an EAF automatic temperature measurement and sampling robot

The function,features,and architecture of a robot that performs automatic temperature measurement and sampling applied on a 150-t AC electric arc furnace(EAF)production line of Baosteel were presented,and the key points of design and revamping experience on the site layout,device protection,lance tool,probe container,measuring position control,and system safety were summarized.Furthermore,a valuable reference for the application of automatic temperature measuring and sampling robots in EAF steelmaking plants will be provided.

Research on the principle of space high-precision temperature control system of liquid crystals based Stokes polarimeter

The magnetic field is one of the most important parameters in solar physics,and a polarimeter is the key device to measure the solar magnetic field.Liquid crystals based Stokes polarimeter is a novel technology,and will be applied for magnetic field measurement in the first space-based solar observatory satellite developed by China,Advanced Space-based Solar Observatory.However,the liquid crystals based Stokes polarimeter in space is not a mature technology.Therefore,it is of great scientific significance to study the control method and characteristics of the device.The retardation produced by a liquid crystal variable retarder is sensitive to the temperature,and the retardation changes 0.09°per 0.10℃.The error in polarization measurement caused by this change is 0.016,which affects the accuracy of magnetic field measurement.In order to ensure the stability of its performance,this paper proposes a high-precision temperature control system for liquid crystals based Stokes polarimeter in space.In order to optimize the structure design and temperature control system,the temperature field of liquid crystals based Stokes polarimeter is analyzed by the finite element method,and the influence of light on the temperature field of the liquid crystal variable retarder is analyzed theoretically.By analyzing the principle of highprecision temperature measurement in space,a high-precision temperature measurement circuit based on integrated operational amplifier,programmable amplifier and 12 bit A/D is designed,and a high-precision space temperature control system is developed by applying the integral separation PI temperature control algorithm and PWM driving heating films.The experimental results show that the effect of temperature control is accurate and stable,whenever the liquid crystals based Stokes polarimeter is either in the air or vacuum.The temperature stability is within±0.0150℃,which demonstrates greatly improved stability for the liquid crystals based Stokes polarimeter.

The dating and temperature measurement technologies for carbonate minerals and their application in hydrocarbon accumulation research in the paleouplift in central Sichuan Basin, SW China

A new method for reconstructing the geological history of hydrocarbon accumulation is developed, which are constrained by U-Pb isotope age and clumped isotope((35)47) temperature of host minerals of hydrocarbon-bearing inclusions. For constraining the time and depth of hydrocarbon accumulation by the laser in-situ U-Pb isotope age and clumped isotope temperature, there are two key steps:(1) Investigating feature, abundance and distribution patterns of liquid and gaseous hydrocarbon inclusions with optical microscopes.(2) Dating laser in-situ U-Pb isotope age and measuring clumped isotope temperature of the host minerals of hydrocarbon inclusions. These technologies have been applied for studying the stages of hydrocarbon accumulation in the Sinian Dengying gas reservoir in the paleo-uplift of the central Sichuan Basin. By dating the U-Pb isotope age and measuring the temperature of clumped isotope((35)47) of the host minerals of hydrocarbon inclusions in dolomite, three stages of hydrocarbon accumulation were identified:(1) Late Silurian: the first stage of oil accumulation at(416±23) Ma.(2) Late Permian to Early Triassic: the second stage of oil accumulation between(248±27) Ma and(246.3±1.5) Ma.(3) Yanshan to Himalayan period: gas accumulation between(115±69) Ma and(41±10) Ma. The reconstructed hydrocarbon accumulation history of the Dengying gas reservoir in the paleo-uplift of the central Sichuan Basin is highly consistent with the tectonic-burial history, basin thermal history and hydrocarbon generation history, indicating that the new method is a reliable way for reconstructing the hydrocarbon accumulation history.

Effect Factors on Measurement Precision of the Embedded Temperature Sensing Fabric

The embedded temperature sensing fabric was designed and woven according to the heat transmission model of the fabric.The temperature sensors were embedded into the multi-layered fabric that weft yarns were high-shrinkage polyester filaments.And the fabric was treated by a self-designed partial heat device,which can make the sensor be fixed in the fabric.The effects of yarn type,yarn linear density,fabric warp density,fabric structure,fabric layer numbers where the sensor is located,and the ambient temperature on the temperature measured value were investigated.The results demonstrated that when the higher thermal conductivity of yarns and lower density yarns were applied in the fabric as rawmaterials,they were favored to improve the measurement precision.Meanwhile,there were many factors that could make the measured values closer to the real value of the body,such as the plain fabric,the increased warp density of the fabric,the multiple-layer fabric where the sensor was located,the raised ambient testing temperature and the prolonged test time in the certain range.

On the Thermal Distribution in Oncological Hyperthermia Treatments

The temperature is one of the principal controlling parameters of oncological hyperthermia. However, local heating forms a complicated thermal distribution in space and has developed over time, too. The decisional factors are the heterogeneity of the targeted volume, the electrolyte perfusions controlled by thermal homeostasis, and the spreading of the heat energy with time. A further complication is that the energy absorption sharply changes by depth, so the spatiotemporal development of the temperature distribution requires specialized methods to control. Most of the temperature imaging facilities (thermography, radiometry, electric impedance tomography, etc.) are less precise than the medical practice needs. In contrast, precise point sensing (like thermocouples, thermistors, and fluoroptical methods) is invasive and measures only a discrete point in the robustly changing thermal map. The two most precise thermal imaging methods, computer tomography, and magnetic resonance are expensive and have numerous technical complications. Our objective is to show the complexity of the temperature distribution inside the human body, and offer a relatively simple and cheap method to visualize its spatiotemporal development. A novel emerging technology, the application of ultrasound microbubble contrast agents is a promising method for solving complicated tasks of thermal distribution deep inside the living body. Noteworthy, the temperature distribution does not determine the full hyperthermia process, nonthermal effects make considerable impact, too. Additionally to the difficulties to measure the thermal heterogeneity during hyperthermia in oncology, numerous nonthermal processes, molecular and structural changes are triggered by the incoming electromagnetic energy, which presently has no spatiotemporal visualization technique. Microbubble imaging has a suitable spatiotemporal thermal resolution, and also it is sensitive to nonthermal effects. Its application for characterization of the modulated electrohyperthermia (mEHT) may open a new theranostic facility, using the synergy of the thermal and nonthermal effects of the radiofrequency delivered energy. This complex approach gives facility to follow the mEHT processes, and the proposed microbubble ultrasound imaging has a particularly promising advantage sensing and acting also nonthermally, having potential to characterize the thermally conditioned nonthermal electromagnetic effects in oncologic hyperthermia. The mEHT combined with microbubble ultrasound images could be a robust theranostic method against cancer.

Fever assessment in children under five: Are we following the guidelines?

BACKGROUND Fever is a common cause of medical consultation and hospital admission,particularly among children.Recently,the United Kingdom’s National Institute for Health and Care Excellence(NICE)updated its guidelines for assessing fever in children under five years of age.The efficient assessment and management of children with fever are crucial for improving patient outcomes.AIM To evaluate fever assessment in hospitalized children and to assess its adherence with the NICE Fever in under 5s guideline.METHODS We conducted a retrospective cohort review of the electronic medical records of children under five years of age at the Department of Pediatrics,Salmaniya Medical Complex,Bahrain,between June and July 2023.Demographic data,vital signs during the first 48 h of admission,route of temperature measurement,and indications for admission were gathered.Fever was defined according to the NICE guideline.The children were divided into five groups according to their age(0-3 months,>3-6 months,>6-12 months,>12-36 months,and>36-60 months).Patients with and without fever were compared in terms of demography,indication for admission,route of temperature measurement,and other vital signs.Compliance with the NICE Fever in the under 5s guideline was assessed.Full compliance was defined as>95%,partial compliance as 70%-95%,and minimal compliance as≤69%.Pearson’sχ^(2),Student’s t test,the Mann-Whitney U test,and Spearman’s correlation coefficient(rs)were used for comparison.RESULTS Of the 136 patients reviewed,80(58.8%)were boys.The median age at admission was 14.2[interquartile range(IQR):1.7-44.4]months,with the most common age group being 36-60 months.Thirty-six(26.4%)patients had fever,and 100(73.6%)were afebrile.The commonest age group for febrile patients(>12-36 months)was older than the commonest age group for afebrile patients(0-3 months)(P=0.027).The median weight was 8.3(IQR:4.0-13.3)kg.Patients with fever had higher weight than those without fever[10.2(IQR:7.3-13.0)vs 7.1(IQR:3.8-13.3)kg,respectively](P=0.034).Gastrointestinal disease was the leading indication for hospital admission(n=47,34.6%).Patients with central nervous system diseases and fever of unknown etiology were more likely to be febrile(P=0.030 and P=0.011,respectively).The mean heart rate was higher in the febrile group than the afebrile group(140±24 vs 126±20 beats per minute,respectively)[P=0.001(confidence interval:5.8-21.9)]with a positive correlation between body temperature and heart rate,r=0.242,n=136,P=0.004.A higher proportion of febrile patients received paracetamol(n=35,81.3%)compared to the afebrile patients(n=8,18.6%)(P<0.001).The axillary route was the most commonly used for temperature measurements(n=40/42,95.2%),followed by the rectal route(n=2/42,4.8%).The department demonstrated full compliance with the NICE guideline for five criteria:the type of thermometer used,route and frequency of temperature measurement,frequency of heart rate measurement,and use of antipyretics as needed.Partial compliance was noted for two criteria,the threshold of fever at 38°C or more,and the respiratory rate assessment in febrile patients.Minimal compliance or no record was observed for the remaining three criteria;routine assessment of capillary refill,temperature reassessment 1-2 h after each antipyretic intake,and refraining from the use of tepid sponging.CONCLUSION This study showed that fever assessment in hospitalized children under five years of age was appropriate,but certain areas of adherence to the NICE guideline still need to be improved.

Rock temperature variability in high-altitude rockfall-prone areas

In a context of cryosphere degradation caused by climate warming,rock temperature is one of the main driving factors of rockfalls that occur on high-elevation mountain slopes.In order to improve the knowledge of this critical relationship,it is necessary to increase measurement capability of rock temperature and its variability in different lithological and slope/aspect conditions,and also to increase local scale studies,increasing the quality and the comparability of the data.This paper shows an example of metrological characterization of sensors used for rock temperature measurement in mountain regions,by means of the measurement uncertainty.Under such approach,data and results from temperature measurements carried out in the Bessanese high-elevation experimental site(Western European Alps)are illustrated.The procedures for the calibration and field characterization of sensors allow to measure temperature in different locations,depths and lithotypes,within 0.10°C of overall uncertainty.This work has highlighted that metrological traceability is fundamental to asses data quality and establish comparability among different measurements;that there are strong differences between air temperature and near-surface rock temperature;and that there are significant differences of rock temperature acquired in different aspect conditions.Finally,solar radiation,slope/aspect conditions and lithotype,seem to be the main driving factors of rock temperature.

Research on the Explosion Temperature Response of Fuel Air Explosive Measured by Colorimetric Pyrometer

An infrared colorimetric radiation thermometrical system was established based on the theory of optical radiation. The dynamic temperature history of fuel air explosive (FAE) was measured to obtain the temperature responses of primary initiation FAE and secondary initiation FAE in real time. And the characteristics of their temperature history curves were compared and analyzed. The results show that the primary initiation FAE has higher explosion temperature and longer duration compared to the secondary initiation FAE.

Numerical investigation on the flow characteristics of a reverse-polarity plasma torch by two-temperature thermal non-equilibrium modelling

A two-temperature(2 T)thermal non-equilibrium model is developed to address the thermal nonequilibrium phenomenon that inevitably exists in the reverse-polarity plasma torch(RPT)and applied to numerically investigate the plasma flow characteristics inside and outside the RPT.Then,a detailed comparison of the results of the 2 T model with those of the local thermal equilibrium(LTE)model is presented.Furthermore,the temperature of the plasma jet generated by a RPT and the RPT’s voltage are experimentally measured to compare and validate the result obtained by different models.The differences of the measured excitation temperature and the arc voltage between the 2 T model and experimental measurement are less than 13%and 8%,respectively,in all operating cases,validating the effectiveness of the 2 T model.The LTE model overestimates the velocity and temperature distribution of the RPT and its plasma jet,showing that thermal non-equilibrium phenomena cannot be neglected in the numerical modelling of the RPT.Unlike other common hot cathode plasma torches,the thermal non-equilibrium phenomenon is found even in the arc core of the RPT,due to the strong cooling effect caused by the big gas flow rate.

High-precision nuclear magnetic resonance probe suitable for in situ studies of high-temperature metallic melts

High-temperature nuclear magnetic resonance(NMR)has proven to be very useful for detecting the temperatureinduced structural evolution and dynamics in melts.However,the sensitivity and precision of high-temperature NMR probes are limited.Here we report a sensitive and stable high-temperature NMR probe based on laser-heating,suitable for in situ studies of metallic melts,which can work stably at the temperature of up to 2000 K.In our design,a well-designed optical path and the use of a water-cooled copper radio-frequency(RF)coil significantly optimize the signal-to-noise ratio(S/NR)at high temperatures.Additionally,a precise temperature controlling system with an error of less than±1 K has been designed.After temperature calibration,the temperature measurement error is controlled within±2 K.As a performance testing,^(27)Al NMR spectra are measured in Zr-based metallic glass-forming liquid in situ.Results show that the S/NR reaches 45 within 90 s even when the sample's temperature is up to 1500 K and that the isothermal signal drift is better than0.001 ppm per hour.This high-temperature NMR probe can be used to clarify some highly debated issues about metallic liquids,such as glass transition and liquid-liquid transition.

Rail temperature variation under heavy haul operations

There currently does not exist in industry a reliable method for the detection of rail foot flaws.Like their head-based counterparts,foot flaws result in broken rail with potentially catastrophic consequences.A proposed area of research for the detection of these flaws is thermography,a non-contact method of measuring and analysing infrared emissions from an object under test.In industry,active excitation thermography is the most common,requiring an excitation source.This paper will present a temperature measurement system and a method of transient temperature extraction from the running rails for the effects of a passing train to evaluate heat transfer in the practical rail environment.The outcomes of these results will provide future direction in the development of a rail heat transfer model and determine if train passage provides enough active excitation for a thermography-based detection technique.

Simultaneous temperature and magnetic field measurements using time-division multiplexing

Nitrogen-vacancy color centers can perform highly sensitive and spatially resolved quantum measurements of physical quantities such as magnetic field,temperature,and pressure.Meanwhile,sensing so many variables at the same time often introduces additional noise,causing a reduced accuracy.Here,a dual-microwave time-division multiplexing protocol is used in conjunction with a lock-in amplifier in order to decouple temperature from the magnetic field and vice versa.In this protocol,dual-frequency driving and frequency modulation are used to measure the magnetic and temperature field simultaneously in real time.The sensitivity of our system is about 3.4 nT=√Hz p and 1.3 mK=√Hz p,respectively.Our detection protocol not only enables multifunctional quantum sensing,but also extends more practical applications.

Thermometry utilizing stored short-wavelength spin waves in cold atomic ensembles

Temperature,as a measure of thermal motion,is a significant parameter characterizing a cold atomic ensemble optical quantum memory.In a cold gas,storage lifetime strongly depends on its temperature and is associated with the spin wave decoherence.Here we experimentally demonstrate a new spin wave thermometry method relying on this direct dependence.The short-wavelength spin waves resulting from the counter-propagating configuration of the control and the probe laser beams make this thermometry highly suitable for probing in situ the atomic motion in elongated clouds as the ones used in quantum memories.Our technique is realized with comparable precision for memories that rely on electromagnetically induced transparency as well as far-detuned Raman storage.

The Real Origin of Climate Change and the Feasibilities of Its Mitigation

The actual treatise represents a synopsis of six important previous contributions of the author, concerning atmospheric physics and climate change. Since this issue is influenced by politics like no other, and since the greenhouse-doctrine with CO2 as the culprit in climate change is predominant, the respective theory has to be outlined, revealing its flaws and inconsistencies. But beyond that, the author’s own contributions are focused and deeply discussed. The most eminent one concerns the discovery of the absorption of thermal radiation by gases, leading to warming-up, and implying a thermal radiation of gases which depends on their pressure. This delivers the final evidence that trace gases such as CO2 don’t have any influence on the behaviour of the atmosphere, and thus on climate. But the most useful contribution concerns the method which enables to determine the solar absorption coefficient βs of coloured opaque plates. It delivers the foundations for modifying materials with respect to their capability of climate mitigation. Thereby, the main influence is due to the colouring, in particular of roofs which should be painted, preferably light-brown (not white, from aesthetic reasons). It must be clear that such a drive for brightening-up the World would be the only chance of mitigating the climate, whereas the greenhouse doctrine, related to CO2, has to be abandoned. However, a global climate model with forecasts cannot be aspired to since this problem is too complex, and since several climate zones exist.

Liquid modified photonic crystal fiber for simultaneous temperature and strain measurement

A liquid modified photonic crystal fiber(PCF)integrated with an embedded directional coupler and multi-mode interferometer is fabricated by infiltrating three adjacent air holes of the innermost layer with standard 1.48 refractive index liquids.The refractive index of the filled liquid is higher than that of background silica,which can not only support the transmitting rod modes but also the"liquid modified core"modes propagating between the PCF core and the liquid rods.Hence,the light propagating in the liquid modified core can be efficiently coupled into the satellite waveguides under the phase-matching conditions,resulting in a dramatic decrease of the resonant wavelength intensity.Furthermore,there is a multi-mode interference produced by modified core modes and rod modes.Such a compact(~0.91 cm)device integrated with an embedded coupler and interferometer is demonstrated for high-sensitivity simultaneous temperature(~14.72 nm∕℃)and strain(~13.01 pm∕με)measurement.

Temperature measurement and analysis of postharvest agricultural products associated with thermal disinfestations

Hot air and hot water treatments are practical,environmentally-friendly and non-chemical heating methods,which are widely used for postharvest insect control and quality preservation in agricultural products.Taking apple and pear as representative fruits,this study mainly analyzed influences of their thermal properties,diameter,and medium speed on the heating rates of fruits through their real-time measured temperatures at surface and center.Based on the reported thermal death kinetic models of the target codling moth,the minimum heating time was estimated to achieve 100%insect mortality.The results showed that the heating rates in fruits decreased gradually with the increasing depth from the surface to the center.With increasing heating time,the heating rate became small.The apple was heated faster than the pear.Hot water was more effective than hot air in treating fruits.Increasing hot air speed increased the heating rate but increasing water circulating speed had no clear effects on the heating rate.Based on the measured temperature-time history of the fruit center,the minimum heating time could be effectively determined for codling moth control through the estimated total equivalent thermal lethal time.The results could provide reliable validation data for the computer simulation and a scientific basis to improve the hot air and hot water treatments.

Empirical Thermal Investigation of Oil-Immersed Distribution Transformer under Various Loading Conditions

The distribution transformer is the mainstay of the power system.Its internal temperature study is desirable for its safe operation in the power system.The purpose of the present study is to determine direct comprehensive thermal distribution in the distribution transformers for different loading conditions.To achieve this goal,the temperature distribution in the oil,core,and windings are studied at each loading.An experimental study is performed with a 10/0.38 kV,10 kVA oil–immersed transformer equipped with forty–two PT100 sensors(PTs)for temperature measurement installed inside during its manufacturing process.All possible locations for the hottest spot temperature(HST)are considered that made by finite element analysis(FEA)simulation and losses calculations.A resistive load is made to achieve 80%to 120%loading of the test transformer for this experiment.Working temperature is measured in each part of the transformer at all provided loading conditions.It is observed that temperature varies with loading throughout the transformer,and a detailed map of temperature is obtained in the whole test transformer.From these results,the HST stays in the critical section of the primary winding at all loading conditions.This work is helpful to understand the complete internal temperature layout and the location of the HST in distribution transformers.

Simulation and experimental analysis of melt pool evolution in laser engineered net shaping

In this work,the evolution of melt pool under single-point and single-line printing in the laser engineered net shaping(LENS)process is analyzed.Firstly,the basic structure of the melt pool model of the LENS process is established and the necessary assumptions are made.Then,the establishment process of the multi-physical field model of the melt pool is introduced in detail.It is concluded that the simulation model results are highly consistent with the online measurement experiment results in terms of melt pool profile,space temperature gradient,and time temperature gradient.Meanwhile,some parameters,such as the 3D morphology and surface fluid field of the melt pool,which are not obtained in the online measurement experiment,are analyzed.Finally,the influence of changing the scanning speed on the profile,peak temperature,and temperature gradient of the single-line melt pool is also analyzed,and the following conclusions are obtained:With the increase in scanning speed,the profile of the melt pool gradually becomes slender;The relationship between peak temperature and scanning speed is approximately linear in a certain speed range;The space temperature gradient at the tail of the melt pool under different scanning speeds hardly changes with the scanning speed,and the time temperature gradient at the tail of the melt pool is in direct proportion to the scanning speed.

Analysis of the blackbody-radiation shift in an ytterbium optical lattice clock

We accurately evaluate the blackbody-radiation shift in a171 Yb optical lattice clock by utilizing temperature measurement and numerical simulation. In this work. three main radiation sources are considered for the blackbody-radiation shift, including the heated atomic oven, the warm vacuum chamber, and the room-temperature vacuum windows. The temperatures on the outer surface of the vacuum chamber are measured during the clock operation period by utilizing seven calibrated temperature sensors. Then we infer the temperature distribution inside the vacuum chamber by numerical simulation according to the measured temperatures. Furthermore, we simulate the temperature variation around the cold atoms while the environmental temperature is fluctuating. Finally, we obtain that the total blackbody-radiation shift is -1.289(7)Hz with an uncertainty of 1.25×10^(-17) for our ^(171)Yb optical lattice clock. The presented method is quite suitable for accurately evaluating the blackbody-radiation shift of the optical lattice clock in the case of lacking the sensors inside the vacuum chamber.