Temperature Probe Research Articles

Impact of age on the management and prognosis of oesophageal fistula after atrial fibrillation ablation - a subanalysis of the worldwide POTTER-AF study

Abstract Background Oesophageal fistula (OF) is a rare but devastating complication following atrial fibrillation (AF) ablation. The data regarding the impact of age on the management and prognosis of OF are scarce. Methods The POTTER-AF study is a worldwide, multi-centre registry conducted under the auspices of the Working Group of Cardiac Electrophysiology of the German Cardiac Society (AGEP, DGK) which evaluated the incidence, management and outcome of post-procedural OF following catheter ablation of AF. A total of 553 729 patients underwent ablation procedures for AF or atrial tachycardia (AT) in 214 electrophysiological centres from 35 countries between 1996 and 2022. Of them, 138 (0.025%) patients experienced postprocedural OF and data regarding the management and prognosis were available in 113 patients. The median age was 63 years. Results A total of 54 (47.8%) patients experiencing OF were younger than 63 years old (Group 1), while 59 (52.2%) patients were at least 63 years old (Group 2). No difference was noted between the groups regarding the incidence of atrioesophageal fistula, oesophageal perforation, and oesophageal-pericardial fistula. Almost half of the patients in each group were females (44.4% vs. 48.3%; p=0.813). As expected, a CHA2DS2-VASc score higher than 3 was more frequent in the older population (61% vs. 17.3%; p<0.001). Regarding the comorbidities, the patients in Group 2 were more likely to suffer from coronary artery disease (25% vs. 9.8%; p=0.046) and hypertension (72.9% vs. 42.6%; p=0.001). The two populations were similar in terms of sedation type, energy source and ablation techniques used, as well as in terms of oesophageal temperature probe utilization. Interestingly, the older population had a shorter median time to symptoms onset (15 (6, 21) vs. 21 (10, 25.3) days; p=0.031). Fever, chest pain and neurological signs as first manifestations of OF showed similar incidences between the groups. When analysing the diagnostic method, the patients from Group 2 were less likely to receive a cranial computed tomography (cCT) or cranial magnetic resonance imaging (cMRI) (25.9% vs. 45.3%; p=0.046). The older population was more likely to receive a direct endoscopic treatment, without surgery (27.6% vs. 11.3%; p=0.035), while there was no difference regarding the rate of surgical treatment. The conservative treatment was used in similar proportions (37.7% in Group 1 vs. 29.3% in Group 2; p=0.421). A clear trend towards a higher mortality was noted in the older population (72.9% vs. 56.6%; p=0.078). The incidence of major and minor sequalae was similar for both groups. Conclusion The median age of the OF population was 63 years. The older population had a shorter time to symptoms onset, was less likely to receive cCT/cMRI as diagnostic method and more likely to be treated by direct endoscopic treatment. The patients older than 63 years showed a trend towards a higher mortality.Time to symptoms onsetOutcome

Impact of gender on the management and prognosis of oesophageal fistula after atrial fibrillation ablation - a subanalysis of the worldwide POTTER-AF study

Abstract Background Oesophageal fistula (OF) is a rare but devastating complication following atrial fibrillation (AF) ablation. The data regarding the impact of gender on the management and prognosis of OF are scarce. Methods The POTTER-AF study is a worldwide, multi-centre registry conducted under the auspices of the Working Group of Cardiac Electrophysiology of the German Cardiac Society (AGEP, DGK) which evaluated the incidence, management, and outcome of post-procedural OF following catheter ablation of AF. A total of 553 729 patients underwent ablation procedures for AF or atrial tachycardia (AT) in 214 electrophysiological centres from 35 countries between 1996 and 2022. Of them, 138 (0.025%) patients experienced postprocedural OF and data regarding the gender, management and prognosis were available in 117 patients. Herein we conducted a gender- based analysis of the patients exhibiting OF. Purpose To evaluate the impact of gender on the management and prognosis of OF. Results Females represented 47% of the study population, which is a notable finding considering that the female population represents only a minority of the patients receiving AF/AT ablation. They were less likely to have atrioesophageal fistula (90.9% vs. 100%; p=0.021). Oesophageal-pericardial fistula occurred solely in females (7.3% vs. 0%; p=0.046). Congestive heart failure was significantly less frequent in the female population (7.4% vs. 26.7%; p=0.012). No other difference was seen between genders regarding the baseline characteristics and comorbidities (Table1). The energy source, ablation technique and utilization of oesophageal temperature probes were similar for males and females. Significantly less women received proton pump inhibitors (PPI) postprocedural (64.8% vs. 84.7%; p=0.017). The median duration until onset of symptoms was 20 days for women and 16.5 days for men (p=0.14), while the median duration until OF diagnosis was 22.5 days and 19.5 days respectively (p=0.217). Significantly more women underwent echocardiography (36.4% vs. 15%; p=0.01) as diagnostic method. More women exhibited stroke (32.7% vs. 14.8%; p=0.040), while there was no significant difference regarding the incidence of septic shock, coma, cardiac arrest, cardiac tamponade, and gastro-intestinal bleeding. Significantly more women than men presented no complications other than OF (9.6% vs. 0%; p=0.026). The females were more likely to undergo endoscopic treatment (35.8% vs. 17.7%; p=0.034), but less likely to undergo direct surgical treatment, without stenting (28.3% vs. 51.6%; p=0.014) (Figure1). The mortality was 63.6% for women and 67.2% for men (p=0.70), with no difference in terms of major and minor sequelae. Conclusion Approximatively half of the patients exhibiting postprocedural OF are females. Women showed a higher rate of endoscopic treatment and a lower rate of direct surgical treatment. The survival, as well as the incidence of minor and major sequelae were similar between genders.

Preparation and Performance of a Fiber Optic Temperature Sensor with Multiple Fluorescence Mechanisms.

The tip of a piece of plastic fiber was dyed with thymol blue to form a temperature probe. The fiber optic sensor was calibrated on a heatboard by comparison with a K-type thermal couple. Fluorescence characteristics including fluorescence intensity, emission bandwidth, peak & barycenter wavelengths, and self-referenced intensity ratio were used to carry the information of environment temperature. Accordingly, more than five temperature sensing functions were retrieved from the fluorescent sensor. Among such functions, the emission band barycenter showed premium precision. Temperature-driven shift of the emission band barycenter has a sensitivity of 0.095nm/K, with a nonlinearity of 2.2%FS, resolution of 4K and repeatability of 1.8%FS. The sensor can find its applications in wearable devices and radiofrequency ablation. Finally in a verification experiment, the sensor was used to monitor the temperature of a microwave oven chamber in real time.

Sensitive, accurate, and high spatiotemporal resolution photonic thermometry

Real-time temperature monitoring with high accuracy and spatiotemporal resolution is critical for many biological applications, including disease diagnosis, drug delivery, and biomedical research. However, traditional methods for measuring temperature in biological systems present difficulties for a variety of reasons, such as slow response time, limited spatial resolution, low amplitude, and susceptibility to electromagnetic interference. Most importantly, in many cases, the thermal mass of temperature probes limits the accuracy and speed of measurement significantly. Here, we show that photonic microring resonators (MRRs) can be used for sensitive, precise, and high spatiotemporal resolution measurement of temperature in the biological milieu. The high refractive index of Si MRR and negligible thermal mass enable sensitive, ultrafast, and accurate temperature transients. By using a double resonator circuit, we demonstrate that MRR sensors can measure temperature with a 1 mm spatial resolution. We then show that MRR yields more accurate results than fiber optic probes for measuring temperature transients. Finally, we demonstrate the localized temperature measurement capability of MRRs in mouse brain tissue heated by superparamagnetic nanoparticles in an alternating magnetic field. This compact, lab-on-chip photonic temperature sensing platform holds great promise for continuous monitoring of temperature in critical biological and biomedical applications.

In situ temperature determination using magnetic resonance spectroscopy thermometry for noninvasive postmortem examinations.

Magnetic resonance spectroscopy (MRS) thermometry offers a noninvasive, localized method for estimating temperature by leveraging the temperature-dependent chemical shift of water relative to a temperature-stable reference metabolite under suitable calibration. Consequentially, this technique has significant potential as a tool for postmortem MR examinations in forensic medicine and pathology. In these examinations, the deceased are examined at a wide range of body temperatures, and MRS thermometry may be used for the temperature adjustment of magnetic resonance imaging (MRI) protocols or for corrections in the analysis of MRI or MRS data. However, it is not yet clear to what extent postmortem changes may influence temperature estimation with MRS thermometry. In addition, N-acetylaspartate, which is commonly used as an in vivo reference metabolite, is known to decrease with increasing postmortem interval (PMI). This study shows that lactate, which is not only present in significant amounts postmortem but also has a temperature-stable chemical shift, can serve as a suitable reference metabolite for postmortem MRS thermometry. Using lactate, temperature estimation in postmortem brain tissue of severed sheep heads was accurate up to 60 h after death, with a mean absolute error of less than 0.5°C. For this purpose, published calibrations intended for in vivo measurements were used. Although postmortem decomposition resulted in severe metabolic changes, no consistent deviations were observed between measurements with an MR-compatible temperature probe and MRS thermometry with lactate as a reference metabolite. In addition, MRS thermometry was applied to 84 deceased who underwent a MR examination as part of the legal examination. MRS thermometry provided plausible results of brain temperature in comparison with rectal temperature. Even for deceased with a PMI well above 60 h, MRS thermometry still provided reliable readings. The results show a good suitability of MRS thermometry for postmortem examinations in forensic medicine.

Fabrication of methylated carbon quantum dot-based fluorescent films for highly sensitive and stable temperature probes

Due to their distinct physicochemical characteristics and outstanding biocompatibility, carbon quantum dots have shown to offer enormous potential in the field of temperature sensing. However, there is still much to learn about the mechanism underlying carbon quantum dots' thermal sensing capabilities, and developing incredibly precise thermometers based on it is still an enormous obstacle. Herein, we successfully fabricated carbon quantum dots with variable luminescence wavelength and temperature-sensitive properties by adjusting the ingredients to modify the composition of functional groups (-NH2, -OH, -COOH and -CH2OH) on the surface of quantum dots in a simple hydrothermal synthesis process, followed by encapsulation with polyvinyl alcohol (PVA). Subsequently, structural/optical characterisation and temperature-dependent studies were utilized for investigations into the quantum dot fluorescence mechanisms as well as the thermal sensing characteristics connected to surface functional groups, respectively. Notably, the designed red-emitting methylenated carbon quantum dot film probe displayed more linear segmented temperature sensing properties (R2>0.99), a wider temperature applicability range (20–160 °C), and high temperature reversibility (20–80 °C, at least 4 cycles). Finally, the mechanism by which functional groups affect the thermal characteristics of carbon quantum dots was addressed, and we hypothesized that intramolecular and intermolecular hydrogen bonding interactions are important factors affecting the thermal properties of carbon dots. This work presents great promise and theoretical guidance for the development of highly reliable carbon quantum dot temperature sensing systems.

An evaluation of the effects of localised skin cooling on microvascular, inflammatory, structural, and perceptual responses to sustained mechanical loading of the sacrum: A study protocol.

This study protocol aims to investigate how localised cooling influences the skin's microvascular, inflammatory, structural, and perceptual tolerance to sustained mechanical loading at the sacrum, evaluating factors such as morphology, physiology, and perceptual responses. The protocol will be tested on individuals of different age, sex, skin tone and clinical status, using a repeated-measure design with three participants cohorts: i) young healthy (n = 35); ii) older healthy (n = 35); iii) spinal cord injured (SCI, n = 35). Participants will complete three testing sessions during which their sacrum will be mechanically loaded (60 mmHg; 45 min) and unloaded (20 min) with a custom-built thermal probe, causing pressure-induced ischemia and post-occlusive reactive hyperaemia. Testing sessions will differ by the probe's temperature, which will be set to either 38°C (no cooling), 24°C (mild cooling), or 16°C (strong cooling). We will measure skin blood flow (via Laser Doppler Flowmetry; 40 Hz); pro- and anti-inflammatory biomarkers in skin sebum (Sebutape); structural skin properties (Optical Coherence Tomography); and ratings of thermal sensation, comfort, and acceptance (Likert Scales); throughout the loading and unloading phases. Changes in post-occlusive reactive hyperaemia will be considered as the primary outcome and data will be analysed for the independent and interactive effects of stimuli's temperature and of participant group on within- and between-subject mean differences (and 95% Confidence Intervals) in peak hyperaemia, by means of a 2-way mixed model ANOVA (or Friedman). Regression models will also be developed to assess the relationship between absolute cooling temperatures and peak hyperaemia. Secondary outcomes will be within- and between-subject mean changes in biomarkers' expression, skin structural and perceptual responses. This analysis will help identifying physiological and perceptual thresholds for the protective effects of cooling from mechanically induced damage underlying the development of pressure ulcers in individuals varying in age and clinical status.

Strategies for High-Accuracy Measurements of Stage Efficiency for a Cooled Turbine

Abstract Gas turbines are used in a broad range of aerospace and land-based applications from power generation to aviation, and their usage is projected to continue to grow. It is therefore critical to improve turbine efficiency thereby reducing fuel consumption and carbon emissions. Demonstration of new efficiency-increasing technologies requires efficiency measurements that are accurate and repeatable. The Steady Thermal Aero Research Turbine (START) Laboratory at the Pennsylvania State University uses a unique 360-deg traversing system for temperature and pressure probes with redundant torque measurements to quantify thermal efficiency for a single-stage cooled test turbine. Flows in the full annulus have been analyzed and compared with subsector traverse segments centered at different circumferential positions to determine the appropriate sector size. The results from this investigation indicate that the full 360-deg measurement is recommended to minimize variation in calculated stage efficiencies. This study also compares the circumferential variations in thermodynamic and mechanical efficiency definitions, finding that the thermodynamic efficiency calculation results in a higher accuracy for full exit plane measurements. A statistical analysis was then performed to determine the number of 360-deg traverse measurements required to achieve a precision uncertainty at most that of the bias uncertainty. This study establishes guidelines to streamline experimental procedures by limiting the necessary test count per day per operating condition to five measurements for at most four test days. Following these procedures establishes a bias of ɛb = 0.19 points, resulting in a total uncertainty of at most ɛt = 0.32 points.

Elevated subgingival temperature infers high bacterial pathogen counts in severe periodontitis.

Periodontal inflammation may be assessed by bleeding on probing and subgingival temperature. This pilot study evaluated the intrapatient relationship between subgingival temperature and selected bacterial groups/species in deep periodontal pockets with bleeding on probing. In each of eightadults, an electronic temperature probe identified three"hot" pockets with elevated subgingival temperature and three"cool" pockets with normal subgingival temperature among premolars/molars with 6‒10 mm probing depths and bleeding on probing. Microbial samples collected separately from the hot and cool periodontal pockets were cultured for selected periodontal pathogens. Hot compared to cool periodontal pockets revealed significantly higher absolute and normalized subgingival temperatures and yielded higher mean proportions of Porphyromonas gingivalis (10.2% for hot vs. 2.5% for cool, p = 0.030) and total red/orange complex periodontal pathogens (48.0% for hot vs. 24.6% for cool, p = 0.012). Hot versus cool deep periodontal pockets harbored significantly higher levels of major periodontal pathogens. Subgingival temperature measurements may potentially be useful to assess risk of periodontitis progression and the efficacy of periodontal therapy.

Simulation of the physical temperature probes for soft sensor design under feed composition changes for naphtha plant

This paper presents a versatile strategy for using simulations to identify control stages of naphtha distillation plant where additional temperature probes can be installed. This search is based on sensitivity analysis applied to the real distillation columns under different operating modes, while simulating the data probed with added thermocouples. It was shown that feed composition has a crucial influence on the resulting position of the control stage(s) and efficiency of the soft sensor (SS) in predicting the quality product. In most practical cases, when the oil field changes, the accuracy of the SS decreases significantly and requires rebuilding, which poses a problem in the control of the technological process. As shown in the paper, SS built with additional thermocouples used as inputs has demonstrated increase in the prediction accuracy under different feed compositions. The effectiveness of the suggested strategy is confirmed by comparing the results with those assuming the use of only physically available probes as inputs for SS.

Perioperative Hypothermia in Elderly Patients During Pelvic Floor Reconstruction Surgery: An Observational Study.

The potential predictors of pelvic floor reconstruction surgery hypothermia remain unclear. This prospective cohort study was aimed at identifying these predictors and evaluating the outcomes associated with perioperative hypothermia. Elderly patients undergoing pelvic floor reconstruction surgery were consecutively enrolled from April 2023 to September 2023. Perioperative temperature was measured at preoperative (T1), every 15min after the start of anesthesia (T2), and 15min postoperative (T3) using a temperature probe. Perioperative hypothermia was defined as a core temperature below 36°C at any point during the procedure. Multivariate logistic regression analysis was conducted to determine factors associated with perioperative hypothermia. A total of 229 patients were included in the study, with 50.7% experiencing hypothermia. Multivariate analysis revealed that the surgical method involving pelvic floor combined with laparoscopy, preoperative temperature < 36.5°C, anesthesia duration ≥ 120min, and the high levels of anxiety were significantly associated with perioperative hypothermia. The predictive value of the multivariate model was 0.767 (95% CI, 0.706 to 0.828). This observational prospective study identified several predictive factors for perioperative hypothermia in elderly patients during pelvic floor reconstruction surgery. Strategies aimed at preventing perioperative hypothermia should target these factors. Further studies are required to assess the effectiveness of these strategies, specifically in elderly patients undergoing pelvic floor reconstruction surgery.

Acute stress augments obstructive apneas and related O2-desaturations in urethane-anesthetised rats via disruption of cholinergic modulation

Obstructive sleep apnea (OSA) is a multifactorial respiratory disorder affecting nearly 1 billon of adults worldwide. Anomalies in respiratory control during sleep contribute to airway obstructions and recurrent desaturations; however, the origins of the problem are not well known. Stress disrupts brain function and increases the risk of OSA co-morbidities, including hypertension and obesity. Because, hypothalamic structures regulating the stress response also project to medullary areas regulating cardiorespiratory function and airway motor control, we hypothesised that exposure to a single stress session is suffcient to induce cardiorespiratory disturbances associated with OSA. Experiments were performed in urethane-anesthetised rats; this approach allows sleep-like brain state alternations with significant reductions in upper airway (genioglossus; GG), but not diaphragmatic (DIA), muscle tone during the transition from NREM-like to REM-like states. Adult male rats were either subjected to a 90 min session of immobilisation stress (n = 21) or handled briefly by the experimenter (n = 18). 24h later, rats were anesthetised (urethane, 1.6 g/kg; i.v.) and instrumented to monitor DIA and GG EMG. O2 saturation was measured by pulse oximetry (S pO2). Blood pressure was measured by an arterial catheter. Rats were placed in a supine position and respiratory airflow was measure by a temperature probe near the nares. Obstructive apneas were identified by the absence of airflow in the presence of DIA activity with a S pO2 drop greater than 3%. Stress did not affect distribution of sleep-like states or the state-related changes in phasic GG activity. However, stress augmented the incidence of obstructive apneas (0.5 vs 2.2 events/h; p = 0.05) and doubled the severity of desaturations associated with apneas (-6% vs -12% drop; p = 0.03). Pre-treatment with atropine (0.5 mg/kg) reduced obstructive apneas (drug effect: p = 0.04). Atropine blocked apnea-related O2 desaturations in stressed but not controls (apnea x stress x atropine: p = 0.04). Atropine treatment augmented GG activity; this effect was greater in NREM-like state, especially in stressed rats (atropine x state x stress: p = 0.05). We conclude that, in urethane anesthetised rats, stress disrupts cardiorespiratory control in ways that favor significant obstructive apneas. Disruption of cholinergic modulation of GG activity and cardiovascular function likely contributes to this process. These data point to an important factor in the onset of OSA. While the frequency of apneas was modest we propose that recurrent exposure to stressors or more significant events will worsen the condition over time. Supported by the Canadian Institutes of Health Research and the Foundation of the Québec Heart &amp; Lung Institute. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Surface-enhanced optical absorption and induced heating in tapered silicon nanoprobes

Subject of study. This study investigates the correlation between the heating temperature and the mesoscopic shape of the Si probe of an atomic force microscope subjected to medium-intensity laser irradiation (5mW/cm2) in the presence of a rough metal substrate. Aim of study. This study aims to quantitatively assess the dependence of optical-field enhancement and induced heating of the tip of a tapered Si nanoprobe, under laser irradiation, on the radius of curvature and cone angle of the probe tip, the distance between the tip and substrate, and the surface roughness of an Au substrate. Method. The localization of the electromagnetic field in the gap between a Si nanoantenna and a defect on the surface of an Au substrate was simulated using the finite-difference time-domain method. A thin Au coating (thickness up to 50 nm) on a glass substrate was used as a plasmonic surface. Owing to the excitation of surface plasmon resonance, such a coating enhances the absorption of light and increases the heating temperature of the Si optical antenna. Main results. The influence of the polarization angle of the incident laser radiation on the distribution of the electric field near the tip of the probe was examined. Only the component of the incident light field along the direction of the probe axis was enhanced near the tip of the Si cantilever. The influence of various parameters, including the radius of curvature, cone angle of the tip of the Si nanoantenna, distance between the probe and substrate, and surface roughness of the Au substrate, on the maximum temperature in the tip region of the Si probe was investigated. The probe temperature was found to decrease with decreasing cone angle of the probe, whereas the temperature of the cantilever tip decreased as the cone angle of the probe tip increased. The dependence of temperature on the radius of curvature of the Si nanoantenna tip in the presence of an Au substrate was evaluated. With an increase in the surface roughness of the Au film, the temperature of the Si antenna tip increased, gradually approaching a limit value. Practical significance. The results of this study are useful for selecting the optimal parameters of an experiment in which a heated probe is used. Controlled heating of a Si probe can facilitate the study of phase transitions in various nanomaterials and that of local thermochemical nanocatalysis for creating new structural materials with specific properties.

Tuning parameters of single quadrupole mass detector hyphenated to supercritical fluid chromatography for enantioseparation of synthetic cathinones

In our previous paper, we introduced a new method for the enantioseparation of cathinones on chiral zwitterion ion exchangers by SFC-ESI-MS with an inverse make-up solvent gradient. The inverse gradient enabled us to stabilize electrospray ionization while simultaneously increasing MS response. In this study, we fine-tuned our previously optimized SFC-ESI-MS method and compared its efficiency with that of the default ESI-MS method. To enhance analyte detection, we designed a complex series of experiments in which all combinations of the following three parameters were evaluated: cone voltage (5 to 27 V), probe temperature (250 to 550 °C) and capillary voltage for positive ionization (0.3 to 1.5 kV). After optimization, various ratios of the make-up solvent (methanol/water/formic acid) introduced before entering the ESI ion source were also tested. Despite this comprehensive testing regime, there were no significant differences between the results obtained for the tuned and default ESI-MS parameters. Similarly, the most suitable make-up solvent composition was the originally used ratio of 90/10/0.1 (v/v/v). These results reinforce the findings of our previous paper, in which we optimized the make-up solvent flow rate and showed its significant impact on ESI-MS response.

A distributed-temperature-sensing-based soil temperature profiler

Abstract. Storage change in heat in the soil is one of the main components of the energy balance and is essential in studying the land–atmosphere heat exchange. However, its measurement proves to be difficult due to (vertical) soil heterogeneity and sensors easily disturbing the soil. Improvements in the precision and resolution of distributed temperature sensing (DTS) equipment has resulted in its widespread use in geoscientific studies. Multiple studies have shown the added value of spatially distributed measurements of soil temperature and soil heat flux. However, due to the spatial resolution of DTS measurements (∼30 cm), soil temperature measurements with DTS have generally been restricted to (horizontal) spatially distributed measurements. This paper presents a device which allows high-resolution measurements of (vertical) soil temperature profiles by making use of a 3D-printed screw-like structure. A 50 cm tall probe is created from segments manufactured with fused-filament 3D printing and has a helical groove to guide and protect a fiber-optic (FO) cable. This configuration increases the effective DTS measurement resolution and will inhibit preferential flow along the probe. The probe was tested in the field, where the results were in agreement with the reference sensors. The high vertical resolution of the DTS-measured soil temperature allowed determination of the thermal diffusivity of the soil at a resolution of 2.5 cm, many times better than what is feasible using discrete probes. A future improvement in the design could be the use of integrated reference temperature probes, which would remove the need for DTS calibration baths. This could, in turn, support making the probes “plug and play” into the shelf instruments without the need to splice cables or experience in DTS setup design. The design can also support the integration of an electrical conductor into the probe and allow heat tracer experiments to derive both the heat capacity and the thermal conductivity over depth at high resolution.

Upconversion photoluminescence and optical temperature probe of Er3+/Yb3+ co-doped LAZT glass prepared by containerless aerodynamic levitation method

xEr3+/yYb3+ co-doped La2O3-Al2O3-ZrO2-TiO2 ([30-(30/88) × (x + y)]La2O3-[58-(58/88) × (x + y)]Al2O3-4ZrO2-8TiO2: x mol% Er2O3/y mol% Yb2O3, x = 2 mol%, and y = 4, 8, 12, 16, 20 mol%, abbreviated as: LAZT: xEr/yYb) glasses were synthesized using a containerless aerodynamic levitation technique. The maximum phonon energy, fluorescence performance and optical temperature measurement performance of the prepared glasses were studied. Raman test shows that the maximum phonon energy of all glasses is less than 355 cm−1, in which the low phonon energy can provide an excellent internal environment for the induction of fluorescence effects. Under excitation at 980 nm, all samples exhibit noticeable red emission peak centering at 662 nm and feeble green emission peak centering at 549 nm at room temperature. The luminous intensity reaches the highest value at x = 2 mol% and y = 12 mol%, at which the concentration quenching phenomenon occurs. The fluorescence mechanism of LAZT: xEr/yYb involves a double-photon process, in which the energy transfer process (ET) accounts for the main part and the excited state absorption process (ESA) accounts for the secondary part. The fluorescence intensity ratio (FIR) can be used for temperature sensing, and the absolute sensitivity FIR reaches maximum value of 1.3 × 10−2 K−1 at 79 K. These results indicate that the LAZT: 2Er/12Yb glass is expected to become a candidate material for non-contact optical temperature probe.

Laboratory and Field Performance Evaluation of Cracking of Airfield Warm Mix Asphalt with Reclaimed Asphalt Pavement at the National Airport Pavement and Materials Research Center

The U.S. Federal Aviation Administration is exploring initiatives to decrease transportation greenhouse gas emissions by developing carbon reduction strategies, including using low-embodied carbon materials, such as reclaimed asphalt pavement (RAP), in airport pavement construction. However, verifying RAP’s viability for airfield pavements with laboratory and field performance measures is essential. This study compared the cracking susceptibility of a P-401 hot mix asphalt and warm mix asphalt (WMA)+RAP airfield mixes using laboratory performance tests and conducted a preliminary evaluation of pavement responses from accelerated pavement testing (APT) fatigue tests. The observations and outcomes presented in this paper found that adding 20% of recycled materials with WMA additives had a decreasing impact in mix performance but did not overly affect the asphalt mix properties, as cracking properties from the different test procedures were found with comparable outcomes. Additional observations from strain gauges and temperature probes in the National Airport Pavement and Materials Research Center test cycle 2 APT fatigue test sections showed that the maximum tensile strains in the WMA surface lane 5 south section were consistently higher than those in the WMA+RAP lane 6 south section, which may be because of the higher load level that it was exposed. Additionally, the hardened or aged RAP binder in the entire lane 6 south section may have increased its stiffness, resulting in lower strain levels than in the lane 5 south section. Notably, both sections showed an increase in tensile strains with an increase in asphalt concrete temperature, which confirmed the temperature dependency behavior of asphalt concrete.

Fermionic quantum turbulence: Pushing the limits of high-performance computing.

Ultracold atoms provide a platform for analog quantum computer capable of simulating the quantum turbulence that underlies puzzling phenomena like pulsar glitches in rapidly spinning neutron stars. Unlike other platforms like liquid helium, ultracold atoms have a viable theoretical framework for dynamics, but simulations push the edge of current classical computers. We present the largest simulations of fermionic quantum turbulence to date and explain the computing technology needed, especially improvements in the Eigenvalue soLvers for Petaflop Applications library that enable us to diagonalize matrices of record size (millions by millions). We quantify how dissipation and thermalization proceed in fermionic quantum turbulence by using the internal structure of vortices as a new probe of the local effective temperature. All simulation data and source codes are made available to facilitate rapid scientific progress in the field of ultracold Fermi gases.

Fabrication of CsPbBr3 nanocrystal/POSS-based copolymer films for non-contact temperature probes

Fluorescence-based non-contact temperature measurement has been attested a widely-used technique for temperature aware in rotating mechanical equipment, electrical devices, and other fields. Inspired by the thermal sensitivity of perovskite nanocrystals, we prepared a CsPbBr3/polyhedral oligomeric silsesquioxane (POSS)-based composite film with outstanding temperature-photoluminescence (PL) dependence, high reversibility, and high hydrophobicity. Perovskites nanocrystals with controllable nanocubic and nanoplate morphologies were synthesized by adjusting the temperature. Various CsPbBr3/POSS-based composite films with different CsPbBr3 morphologies and ratios were fabricated. The CsPbBr3 nanocubic and nanoplate based films possessed high hydrophobicity, UV stability, and thermal stability. Temperature dependence experiments revealed that PL spectral parameters of CsPbBr3/POSS-based composite films had obvious temperature change characteristics attributable to the CsPbBr3 morphology. The PL intensity and full width at half maximum (FWHM) of the CsPbBr3 nanoplate based film exhibited poor regularity with temperature. In contrast, the PL intensity of the CsPbBr3 nanocubic based film was related to temperature exponentially, and the FWHM had a strong linear relationship with temperature. Moreover, temperature dependence reversibility was realized for the CsPbBr3 nanocubic based film. Furthermore, the applicability of a CsPbBr3 nanocubic based temperature probe was verified by monitoring the temperature of a bearing cage on a spindle-bearing test platform. The CsPbBr3/POSS-based composites can be applied as temperature probes for non-contact temperature measurement of rotating components of mechanical equipment.

Urban heat load assessment in Zagreb, Croatia: a multi-scale analysis using mobile measurement and satellite imagery.

A limited number of meteorological stations and sparse data challenge microclimate assessment in urban areas. Therefore, it is necessary to complement these data with additional measurements to achieve a denser spatial coverage, enabling a detailed representation of the city's microclimatic features. In this study, conducted in Zagreb, Croatia, mobile air temperature measurements were utilized and compared with satellite-derived land surface temperature (LST). Here, air temperature measurements were carried out using bicycles and an instrument with a GPS receiver and temperature probe during a heat wave in June 2021, capturing the spatial pattern of air temperature to highlight the city's microclimate characteristics (i.e. urban heat load; UHL) in extremely hot weather conditions. Simultaneously, remotely sensed LST was retrieved from the Landsat-8 satellite. Air temperature measurements were compared to city-specific street type classification, while neighbourhood heat load characteristics were analysed based on local climate zones (LCZ) and LST. Results indicated significant thermal differences between surface types and urban forms and between street types and LCZs. Air temperatures reached up to 35 °C, while LST exceeded 40 °C. City parks, tree-lined streets and areas near blue infrastructure were 1.5-3 °C cooler than densely built areas. Temperature contrasts between LCZs in terms of median LST were more emphasised and reached 9 °C between some classes. These findings highlight the importance of preserving green areas to reduce UHL and enhance urban resilience. Here, exemplified by the city of Zagreb, it has been demonstrated that the use of multiple datasets allows a comprehensive understanding of temperature patterns and their implications for urban climate research.