Observed Temperature Distribution Research Articles

Optimalisasi Citra Termal dalam Pertanian Presisi untuk Deteksi Dini Masalah Kesehatan Bibit Kelapa Sawit

The palm oil industry plays a pivotal role in various sectors, including food and bioenergy. The success of oil palm cultivation relies heavily on the health of the plant's seedlings. Early detection of diseases and stress is crucial to prevent a decline in crop yields and financial losses. Infrared Thermography technology has been widely employed across various fields for non-destructive monitoring, including agriculture. This research focuses on optimizing the use of thermal imaging in precision agriculture to early detect health issues in oil palm seedlings. Thermal imaging enables the precise measurement of plant surface temperatures, facilitating the identification of plant health issues without the need for further visual intervention. This study has the potential to transform approaches to proactively monitoring and managing the health of oil palm plants. Infrared thermography technology is utilized to observe temperature distribution patterns in oil palm seedlings. The objective is to explore the correlation between thermal characteristics and potential health issues or symptoms in these seedlings. Samples used in the research involve Tenera variety oil palm seedlings aged between 5-9 months, a critical growth phase. The study employs the UNI-T UTi120 Mobile thermal camera capable of measuring temperatures ranging from -20°C to 400°C. Subsequently, thermal image processing is conducted to identify thermal characteristics that could serve as indicators of health issues in oil palm seedlings. Statistical analysis is then performed to test significant differences in thermal characteristics between healthy and unhealthy plant samples. The analysis results reveal significant temperature variations between healthy and unhealthy portions of the plant seedlings, with a significance value of 0,025. These findings can serve as a basis for identifying temperature changes as potential early indicators of health issues in oil palm seedlings. This provides a foundation for developing more effective precision agriculture approaches within the palm oil industry.

The dusty heart of Circinus

In this paper we present the first-ever L- and M-band interferometric observations of Circinus, building upon a recent N-band analysis. We used these observations to reconstruct images and fit Gaussian models to the L and M bands. Our findings reveal a thin edge-on disk whose width is marginally resolved and is the spectral continuation of the disk imaged in the N band to shorter wavelengths. Additionally, we find a point-like source in the L and M bands that, based on the LMN-band spectral energy distribution fit, corresponds to the N-band point source. We also demonstrate that there is no trace of direct sightlines to hot dust surfaces in the circumnuclear dust structure of Circinus. By assuming the dust is present, we find that obscuration of AV ≳ 250 mag is necessary to reproduce the measured fluxes. Hence, the imaged disk could play the role of the obscuring “torus” in the unified scheme of active galactic nuclei. Furthermore, we explored the parameter space of the disk + hyperbolic cone radiative transfer models and identify a simple modification at the base of the cone. Adding a cluster of clumps just above the disk and inside the base of the hyperbolic cone provides a much better match to the observed temperature distribution in the central aperture. This aligns well with the radiation-driven fountain models that have recently emerged. Only the unique combination of sensitivity and spatial resolution of the VLTI allows such models to be scrutinized and constrained in detail. We plan to test the applicability of this detailed dust structure to other MATISSE-observed active galactic nuclei in the future.

Novel experimental technique to evaluate soil thermal conductivity in a transient state

novel experimental technique to evaluate soil thermal conductivity in a transient state

Numerical investigation of performance for liquid-cooled cylindrical electrical vehicle battery pack using Al2O3/EG-water nano coolant

Globally Electrical vehicles (EVs) demands increasing as it is eco-friendly and cost-effective compared to fossil fuel vehicles. To enhance safety and life of battery, thermal performance study of EV battery pack is most crucial. This paper presents computational investigation of liquid cooled battery pack. Here, for immersion cooling system study, in Ansys Fluent, the Lumped model of battery is considered to observe temperature distribution over battery surface during discharge at 1C to 4C current rate using Al2O3/EG-water dispersion as the cooling medium. All individual batteries are covered by polylactic acid (PLA) material cylinder and whole pack is immersed in Al2O3/EG-water nano coolant box. Nanoccolant with 1, 2, 3, 4 and 5 % volume fraction of Al2O3 is circulated over the battery enclosure surface with a velocity 0.1 to 0.5 m/s. It is found that volume fraction 4% and more of Al2O3/EG-Water Nanocoolant can be able to maintain battery temperature maximum 50 0C.

Comparison of the corrugated steel web composite box-girder and traditional girders regarding temperature field under solar radiation

The corrugated web composite box-girder (CWCB) is a novel structural form and has been widely adopted in bridge engineering due to its excellent mechanical properties and construction convenience. However, researches on the temperature field in CWCB is very limited, which may augment the risk of concrete cracking and steel web bucking and deteriorate the durability of bridge structures. This paper thereby experimentally investigates the time-varying and spatial temperature distribution features of CWCB based on a long-term temperature monitoring system. The experimental results indicate that the temperature field in CWCB is non-uniformly distributed and the vertical and horizontal temperature differences can reach up to 13.4 ℃ and 19.1 ℃, respectively. Meanwhile, the observed temperature distribution profile of the experimental CWCB is varying with seasons owing to the different exposure to solar radiation. Then, a refined numerical thermal simulation approach is developed and its reliability and accuracy have been validated by the experimental temperature data of three types of box-girders, i.e., CWCB, ordinary composite box-girder (OCB), and conventional concrete box-girder (CCB). Based on the validated numerical approach, the temperature fields of three full-sized box-girders are therewith compared and the results demonstrate that the temperature field in CWCB is much more complicated than the traditional box-girders. Besides, the obtained cross-sectional temperature differences of CWCB are significantly larger than that of the traditional box-girders. Finally, two temperature profiles have been proposed to characterize the thermal actions in CWCB, which are composed of parabolas and polylines. The outcome of this study can provide a useful tool for analyzing the temperature field and calculating the design thermal load of CWCB.

High rate response of elastomeric coatings for wind turbine blade erosion protection evaluated through impact tests and numerical models

The high strain rate (above ∼104/s) behavior of an elastomer is characterized using low strain rate (below ∼101/s) dynamic mechanical thermal analysis and time–temperature superposition. This approach is validated using high strain rate ball impact experiments and finite element predictions of ball deformations and rebound speeds. The ball impact experiments are performed by shooting 6 mm rubber balls with a controlled impact speed of 50–170 m/s at steel and polyurethane targets. An explicit axisymmetric finite element model of the ball impact experiment is established in the commercial code Abaqus. The validated material properties are used to model the viscously dissipated energy and the corresponding temperature increase in the polyurethane target. The region with the largest dissipated energy in the target material is predicted to be in a ring around the impact center with a radius of approximately 1 mm. This region corresponds well to locations of early damage initiation observed in the impact fatigue experiments for similar materials. The predictions are confirmed by the observed temperature distributions using thermal camera imaging of the rubber ball impact experiment. The experimental setup was developed for impact fatigue testing of anti-erosion coatings for the leading-edges of wind turbine blades.

Zone-specific temperature distribution, densification trajectory and grain-growth kinetics of microwave-hybrid-sintered and conventionally sintered Al2O3 slip casts

ABSTRACT A comparative study on the microwave hybrid sintering and conventional sintering of Al2O3 slip casts is reported to observe temperature distribution, grain-growth kinetics and densification in different regions of samples. It was found that the microwave hybrid sintering resulted in a significantly lower temperature difference between the surface and the center as compared to that in conventional sintering. Remarkably, in the microwave-hybrid-sintered samples, the estimated activation energy for grain growth at the center was approximately 27% lower than that at the surface in the conventionally sintered samples. The grain-growth rate in microwave hybrid sintering was more than three times higher at the sample center ((62.07 ± 0.06) × 10–21 m3/s) than at the sample surface in the conventional sintering ((18.75 ± 0.11) × 10–21 m3/s). The volume diffusion for grain growth was found to be the most effective mechanism in all samples, irrespective of the sintering technique and point of observation. It is suggested that the heat-flux, as well as the microwave effect and influence of surface charge due to the electric field of the field-assisted process were the reasons for these outcomes.

Frictional heating in a thick fault zone with empirical slip-weakening friction: implications for slip parameter estimation from temperature observations in deep fault drilling

The strain energy released during an earthquake is consumed by processes related to seismic radiation or dissipation. Deep fault drilling and subsequent temperature measurements in a thick fault zone immediately after an event have provided important insights into this dissipation process. By employing an analytical solution to the heat conduction problem, which involves the sudden injection of an infinitesimally thin heat source into an infinite medium, previous drilling projects have estimated the strength of the heat source and the level of shear stress from observed temperature anomalies. However, it is unclear under what conditions this analytical source solution can be regarded as a good approximation for the thick fault problem, a situation which has led to uncertainty of the approximation error in these previous studies. In this study, I first derived an analytical solution for the thick fault problem that accounted for experimentally derived slip-weakening friction. I then validated the derived solution both analytically and numerically. Using the derived thick solution, I next demonstrated that the thick, planar, and source solutions can be considered equivalent under the typical conditions of the previous drilling projects. Therefore, the slip parameters estimated by using the source solution obtained by these studies are appropriate. These results suggest that coseismic information with spatio-temporal extent, such as shear stress and friction coefficient, are lost due to heat diffusion when the temperature observations are conducted; thus, they cannot be inferred directly from observed temperature anomalies. These results also suggest that for most drilling projects, including future ones, the observed temperature distribution can be well explained by using the source solution instead of the thick solution as long as coseismic slip is not markedly delocalized and the spatial extent of the temperature measurements is not significantly larger than the diffusion length.

Ambient warming and human sleep duration and timing: a worldwide case-crossover study using big data from wearable devices

BACKGROUND AND AIM: Only limited self-report evidence links outdoor temperatures with alterations in sleep. We aimed to assess the attributable impact of nighttime minimum temperature on objectively recorded sleep outcomes. METHODS: In a global natural experiment, we linked over 10 billion minute-level sleep measurements comprising 7.41 million nightly sleep records (n=47,628) from accelerometer-based wristbands to daily meteorological data across 68 countries between 2015 and 2017. We used person-level longitudinal panel fixed effects models to isolate the within-person sleep impact attributable to nighttime temperature. The primary endpoints were sleep timing and total time asleep. RESULTS:Controlling for potential device-specific, person-specific, location-specific, and temporal confounds, warmer temperatures were associated with reduced sleep duration across the observed temperature distribution. Within-person sleep duration declined by 6.11 minutes per every 10°C increase when nighttime minimum temperatures exceeded 10°C. During nights over 25°C, sleep onset was delayed by 5.92 minutes, sleep offset advanced by 2.51 minutes and the probability of short 7hr sleep increased by 3.50 percentage points compared to the median temperature reference range of 5-10°C. The negative relationship between a 1°C increase in ambient temperature and sleep duration was more acute for the elderly compared to middle aged adults, for females compared to males, and residents of lower income countries compared to residents of high income countries. There was no evidence for short term acclimatization or intraday sleep substitution with daytime rest. CONCLUSIONS:Warmer nighttime ambient temperatures were associated with reduced and delayed sleep. This evidence suggests a plausibly causal pathway through which rising temperatures may contribute to global health inequalities if unmitigated climate change continues. Employing 21 global climate models, we project that climate change may cumulatively erode adult sleep by 23.40 hours (warmest regions) to 5.40 hours (coldest regions) annually under a high emissions scenario, barring further adaptation. KEYWORDS: Climate, Big Data, Mental health outcomes, Causal inference, Sleep

The performance of CORDEX-EA-II simulations in simulating seasonal temperature and elevation-dependent warming over the Tibetan Plateau

To explore the driving mechanisms of elevation-dependent warming (EDW) over the Tibetan Plateau (TP), the output from a suite of numerical experiments with different cumulus parameterization schemes (CPs) under the Coordinated Regional Climate Downscaling Experiments-East Asia (CORDEX-EA-II) project is examined. Results show that all experiments can broadly capture the observed temperature distributions over the TP with consistent cold biases, and the spread in temperature simulations commonly increases with elevation with the maximum located around 4000–5000 m. Such disagreements among the temperature simulations could to a large extent be explained by their spreads in the surface albedo feedback (SAF). All the experiments reproduce the observed EDW below 5000 m in winter but fail to capture the observed EDW above 4500 m in spring. Further analysis suggests that the simulated EDW during winter is mainly caused by the SAF, and the clear-sky downward longwave radiation (LWclr) plays a secondary role in shaping EDW. The models’ inability in simulating EDW during spring is closely related to the SAF and the surface cloud radiative forcing (CRFs). Furthermore, the magnitude and structure of the simulated EDW are sensitive to the choice of CPs. Different CPs generate diverse snow cover fractions, which can modulate the simulated SAF and its effect on EDW. Also, the CPs show great influence on the LWclr via altering the low-level air temperature. Additionally, the mechanism for different temperature changes among the experiments varies with altitudes during summer and autumn, as the diverse temperature changes appear to be caused by the LWclr for the low altitudes while by the SAF for the middle-high altitudes.

Chemical abundances in Seyfert galaxies – V. The discovery of shocked emission outside the AGN ionization axis

ABSTRACT We present maps for the electron temperature in the inner kpc of three luminous Seyfert galaxies: Mrk 79, Mrk 348, and Mrk 607 obtained from Gemini Multi-Object Spectrograph-integral field unit observations at spatial resolutions of ∼110–280 pc. We study the distributions of electron temperature in active galaxies and find temperatures varying in the range from ∼8000 to $\gtrsim 30\, 000\,$K. Shocks due to gas outflows play an important role in the observed temperature distributions of Mrk 79 and Mrk 348, while standard photoionization models reproduce the derived temperature values for Mrk 607. In Mrk 79 and Mrk 348, we find direct evidence for shock ionization with overall orientation orthogonal to the ionization axis, where shocks can be easily observed as the active galactic nuclei radiation field is shielded by the nuclear dusty torus. This also indicates that even when the ionization cones are narrow, the shocks can be much wider angle.

Drying Performance and Aflatoxin Content of Paddy Rice Applying an Inflatable Solar Dryer in Burkina Faso

The drying performance of paddy rice using an inflatable solar dryer (ISD), or also known as GrainPro® Solar Bubble Dryer™, was evaluated and compared to conventional sun drying in Burkina Faso. Drying time was around eight hours. Thermal imaging was conducted to observe temperature distribution in the ISD during drying and mixing. Shadow casting was observed in the ISD due to the round shape of the black plastic film, which reduced the temperature of the paddy rice to about 10 °C. The temperature inside the ISD was up to 13 °C higher than the ambient temperature, whereas the temperature of paddy rice on the top layer was about 5 °C higher than on the bottom. The final moisture content of paddy rice dried in the ISD and under the sun was not considerably different. Under certain circumstances, impurities in paddy rice dried in the ISD could be substantially lower than for sun drying. The aflatoxin level of paddy rice was under the maximum limit of the EU regulation. Drying paddy rice seemed to be effective to remove aflatoxin type AFG2 content. Further adaptation of the ISD design for drying operations on rough surfaces and sandy soils is suggested.

Methodology for the Measurement of the Heat Partitioning by Thermal Imaging in the Orthogonal Cutting Process

The thermal conditions like temperature distribution and heat fluxes during metal cutting have a major influence on the machinability, the tool life time, and the metallurgical structure of the work piece material. Though numerous analytical and experimental efforts have been developed in order to understand the thermal conditions in metal cutting, many questions still prevail. So, the exact form, distribution, and intensity of heat sources in the primary and secondary shear zone, which may describe the observed temperature distributions, are not explored to a satisfactory extend. On the other hand, the influence of the material properties like friction coefficient, heat conductivity, and shear strength is not yet fully understood. Another essential question is the heat flux partition among chip, work piece, and tool depending on process parameters and material. The particular novelty of the current investigation is a new methodological approach using modern thermal measurement system and postprocessing methods in order not only to measure the entire temperature field in the orthogonal cutting zone but also to calculate the affiliated heat flow distribution in the cutting process. Thus, the cutting process is treated as energy conversation process of the governing mechanical power into sensible heat. This point of view offers compatibility across process parameters and materials, thus new possibilities for process design.

Measurement of local temperature around the impact points of fast ions under grazing incidence

Gold and platinum nanoparticles of few-nm size were deposited on amorphous silicon nitride (a-SiN) films. These samples were irradiated with 380 MeV Au ions at grazing incident angles (θi = 2°–5°) to a fluence of ∼1 × 1010 ions/cm2. The irradiated samples were observed using transmission electron microscopy (TEM). Ion tracks were clearly observed as long bright lines. Nanoparticles were found to be desorbed from long and narrow regions along the ion tracks. The surface temperature at the thermal spike produced by the ion impact was evaluated from the observed nanoparticle desorption. The observed temperature distribution is qualitatively explained by a one-dimensional two temperature model (1D-TTM) although there are some discrepancies which may be attributed to the surface effects which are not taken into account in 1D-TTM.

On the Efficiency of Thermal Conduction in Galaxy Clusters

Abstract Galaxy clusters host a large reservoir of diffuse plasma with radially varying temperature profiles. The efficiency of thermal conduction in the intracluster medium (ICM) is complicated by the existence of turbulence and magnetic fields, and has received a lot of attention in the literature. Previous studies suggest that the magnetothermal instability developed in outer regions of galaxy clusters would drive magnetic field lines to be preferentially radial, resulting in efficient conduction along the radial direction. Using a series of spherically symmetric simulations, here we investigate the impact of thermal conduction on the observed temperature distributions in the outer regions of three massive clusters, and find that thermal conduction substantially modifies the ICM temperature profile. Within 3 Gyr, the gas temperature at a representative radius of 0.3r 500 typically decreases by ∼10%–20% and the average temperature slope between 0.3r 500 and r 500 drops by ∼30%–40%, indicating that the observed ICM would not stay in a long-term equilibrium state in the presence of thermal conduction. However, X-ray observations show that the outer regions of massive clusters have remarkably similar radially declining temperature profiles, suggesting that they should be quite stable. Our study thus suggests that the effective conductivity along the radial direction must be suppressed below the Spitzer value by a factor of 10 or more, unless additional heating sources offset conductive cooling and maintain the observed temperature distributions. Our study provides smoking-gun evidence for the suppression of parallel conduction along magnetic field lines in low-collisionality plasmas by kinetic mirror or whistler instabilities.

Thermal Performance Investigation of Concentrated Solar Collector Using Novel Aluminum Absorber

The present work, investigate effect of incident solar radiation, inlet fluid temperature and mass flow rates on thermal performance of Compound Parabolic Collector (CPC). CPC of 2m X 3m size, 5.88 m2 aperture areas with 3° acceptance angle was designed and mounted in east-west direction. A triangular absorber made up of aluminum was designed and manufactured to carry out outdoor experimentation in the Mumbai, India (19.0216° N and 72.8646° E) on clear sunny days. CPC with Single axis manual tracking covered with mirror strip glass as a reflecting cover execute tracking in north-south direction. Infrared camera with Thermoanalyzer software was used to study & observe temperature distribution over the surface of absorber. Experimental works were performed using water, flows through the absorber. Experimental investigation concludes that, thermal efficiency of system linearly increases with mass flow rate and incident solar radiations. Thermal efficiency in experimental work varies from 35-39% for the mass flow rates of 0.58 lit/sec -0.75 lit/sec© 2017 Elsevier Ltd. All rights reserved.Selection and/or Peer-review under responsibility of 7th International Conference of Materials Processing and Characterization.

Numerical study of titanium melting by high frequency inductive heating

High frequency induction heating process of titanium wire is investigated numerically and experimentally. The electromagnetic thermal and fluid fields during high frequency induction heating process are calculated. The effects of current frequency and current value of coil on the thermal and flow fields are numerically studied. The change of the applied current has profounder influence on the melting rate than the change of current frequency did. The simulation results are verified by experiments, and good agreement with simulation. With the ability to observe temperature distribution in titanium wire during high frequency induction heating, the numerical simulation method is demonstrated to be a cost-effective tool in predicting the process of high frequency induction heating of titanium wire.

Temperature distribution monitoring of a coiled flow channel in microwave heating using an optical fiber sensing technique

We demonstrate the temperature distribution monitoring of a coiled flow channel in a microwave reactor that was designed for microwave-assisted continuous-flow synthesis. The monitoring is conducted using an optical fiber sensing technique, which can monitor the temperature distribution along the coiled flow channel. The sensing system successfully observed the inhomogeneous nature of the microwave heating, and the effect of water flow on the temperature distribution. We discuss the cause of the inhomogeneous heating by comparing the observed temperature distributions and the electric fields inside the reactor, as calculated by numerical simulations.

Periodic Dynamic Thermography for Breast Cancer Assessment

In this paper we propose Periodic Dynamic Thermography (PDT), in conjunction with Image processing and Analysis, to be an easy to use procedure involving capturing thermal images of the breast. The authors present a proof of concept study for subjects to image their own breasts periodically, starting from early ages of adolescence, where mammography is not recommended. Utilizing the proposed procedure, it is envisaged that each subject will establish historical thermal images of their own breasts where they can later be analyzed, by a physician, to assess the causes of thermal changes identified on the surface of the breast. Towards this end we have utilized phantoms, solved the heat transfer equations for the phantom shape boundary conditions with COMSOL, and confirmed the resulting thermal distribution with the observed temperature distribution for the phantoms. Based on this model’s promising results we propose the development of a system to capture thermographic images of the subject from their early years in life, periodically (monthly or bi-weekly), with image analysis application software to be used as an assessment tool to alert the subject of any abnormal thermal changes.

Long-term structural health monitoring of the Cleddau bridge: evaluation of quasi-static temperature effects on bearing movements

This paper illustrates how long-term measurements can be analysed to understand bridge behaviour under changing environmental conditions and how the developed understanding can help explain the performance of its critical components. Measurements from the Cleddau bridge, a structure that has been continuously monitored for more than two years, are used to investigate thermal effects in steel box-girder bridges and, in particular, their bearings. Observed temperature distributions are very different to the recommended distributions in design codes (BS EN 1991-5: 2003). These temperature distributions create plan bending of the box girder, which in turn impose forces at the bearings that have contributed to its wear. This paper investigates bearing movements of the bridge using numerical models, and estimates the resulting forces at the supports. A physics-based model of the bridge is created to which temperature distributions inferred from in situ measurements are supplied as input. Model predictions are validated against measured deformations at the bearings. Subsequently the model is used to predict forces at the bearings due to plan bending and bearing locking. Results quantify the impact that thermal effects have on the performance of the bearings. They also highlight the significance of considering a range of temperature distribution scenarios that go beyond those given in the design codes in order to reliably evaluate thermal effects at the design stage.