Research note: Leaf cooling curves: measuring leaf temperature in sunlight

2006 ◽  
Vol 33 (5) ◽  
pp. 515 ◽  
Author(s):  
Andrea Leigh ◽  
John D. Close ◽  
Marilyn C. Ball ◽  
Katharina Siebke ◽  
Adrienne B. Nicotra
Keyword(s):  
Surface Temperature ◽  
Close Agreement ◽  
Leaf Surface ◽  
Specular Reflection ◽  
Leaf Temperature ◽  
Cooling Curve ◽  
Cooling Curves ◽  
Infrared Studies ◽  
Leaf Level ◽  
The Difference

Despite the obvious benefits of using thermography under field conditions, most infrared studies at the leaf level are generally conducted in the laboratory. One reason for this bias is that accuracy can potentially be compromised in sunlight because reflected radiation from the leaf might affect the calculation of the temperature measurement. We have developed a method for measuring leaf temperature in sunlight by using thermal imagery to generate cooling curves from which the time constant for cooling, τ, can be calculated. The original temperature of the sunlit leaf may be determined by extrapolating backwards in time. In the absence of specular reflection, there is close agreement between the extrapolated sunlit temperature and the sunlit temperature recorded by the camera. However, when reflected radiation is high, the difference between the initial (incorrect) temperature determined from the sunlit image and the temperature extrapolated from the cooling curve can be > 2°C. Notably, our results demonstrate a close agreement between the extrapolated sunlit temperature and the temperature of the leaf approximately 1 s after being shaded, suggesting that this shaded image provides a good estimate of the original sunlit temperature. Thus, our technique provides two means for measuring leaf surface temperature in sunlight.

scholarly journals Water-Stressed Plants Do Not Cool: Leaf Surface Temperature of Living Wall Plants under Drought Stress

2021 ◽  
Vol 13 (7) ◽  
pp. 3910
Author(s):  
Michael Gräf ◽  
Markus Immitzer ◽  
Peter Hietz ◽  
Rosemarie Stangl
Keyword(s):  
Drought Stress ◽  
Surface Temperature ◽  
Leaf Surface ◽  
Canopy Temperature ◽  
Infrared Camera ◽  
Control Group ◽  
Thermal Cameras ◽  
Living Wall ◽  
Leaf Level ◽  
Vertical Greening

Urban green infrastructures offer thermal regulation to mitigate urban heat island effects. To gain a better understanding of the cooling ability of transpiring plants at the leaf level, we developed a method to measure the time series of thermal data with a miniaturized, uncalibrated thermal infrared camera. We examined the canopy temperature of four characteristic living wall plants (Heuchera x cultorum, Bergenia cordifolia, Geranium sanguineum, and Brunnera macrophylla) under increasing drought stress and compared them with a well-watered control group. The method proved suitable to evaluate differences in canopy temperature between the different treatments. Leaf temperatures of water-stressed plants were 6 to 8 °C higher than those well-watered, with differences among species. In order to cool through transpiration, vegetation in green infrastructures must be sufficiently supplied with water. Thermal cameras were found to be useful to monitor vertical greening because leaf surface temperature is closely related to drought stress. The usage of thermal cameras mounted on unmanned aerial vehicles could be a rapid and easy monitoring system to cover large façades.

scholarly journals Modeling of Two-Stage Solidification: Part II Computational Verification of the Model

2013 ◽  
Vol 13 (1) ◽  
pp. 125-130 ◽  
Author(s):  
O. Wodo ◽  
E. Gawrońska
Keyword(s):  
Analytical Model ◽  
Close Agreement ◽  
Cooling Curve ◽  
Cooling Curves ◽  
Two Stage ◽  
Cooling Rates ◽  
Solidification Model ◽  
Eutectic Transformation

Abstract In Part I of this article, two-stage solidification model was presented. In this part we use our model to simulate solidification of the Al 7% Si alloy for two cooling rates -2 deg/s and -20 deg/s . Simulations have been performed for two eutectic transformation modes, typical for modified and unmodified alloys. Obtained cooling curves are qualitatively consistent with the typical cooling curves for modified and unmodified alloys. Moreover, evolution of cooling-curve characteristics is compared with the analytical model and found to be in close agreement.

Ocular surface temperature differences in glaucoma

2021 ◽  
pp. 112067212110237
Author(s):  
Ari Leshno ◽  
Ori Stern ◽  
Yaniv Barkana ◽  
Noa Kapelushnik ◽  
Reut Singer ◽  
...  
Keyword(s):  
Surface Temperature ◽  
Thermal Imaging ◽  
Ocular Surface ◽  
Open Angle Glaucoma ◽  
Tissue Temperature ◽  
Body Temperatures ◽  
Current Thinking ◽  
Imaging Camera ◽  
The Mean ◽  
The Difference

Purpose: Accumulating evidence suggests that neuroinflammation and immune response are part of the sequence of pathological events leading to optic nerve damage in glaucoma. Changes in tissue temperature due to inflammation can be measured by thermographic imaging. We investigated the ocular surface temperature (OST) profile of glaucomatous eyes to better understand the pathophysiology of these conditions. Methods: Subjects diagnosed with glaucoma (primary open angle glaucoma [POAG] or pseudo exfoliation glaucoma [PXFG]) treated at the Sam Rothberg Glaucoma Center (11/2019–11/2020.) were recruited. Healthy subjects with no ocular disease served as controls. The Therm-App thermal imaging camera was used for OST acquisition. Room and body temperatures were recorded, and the mean temperatures of the medial cantus, lateral cantus, and cornea were calculated with image processing software. Results: Thermographic images were obtained from 52 subjects (52 eyes: 25 POAG and 27 PXFG) and 66 controls (66 eyes). Eyes with glaucoma had a significantly higher OST compared to controls (mean 0.9 ± 0.3°C, p < 0.005). The difference between the two groups remained significant after adjustment for age, sex, intraocular pressure (IOP) and room and body temperatures. Lens status and topical IOP-lowering medication did not significantly affect OST. A subgroup analysis revealed that the OST was higher among eyes with POAG compared to eyes with PXFG, but not significantly. Conclusions: Differences in the OST between glaucomatous and normal eyes strengthens current thinking that inflammation affects the pathophysiology of glaucoma. Longitudinal studies are warranted to establish the prognostic value of thermographic evaluations in these patients.

scholarly journals The Value of a Decrease in Temperature by One Degree Celsius of the Regional Microclimate—The Cooling Effect of the Paddy Field

Atmosphere ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 353
Author(s):  
Ya-Wen Chiueh ◽  
Chih-Hung Tan ◽  
Hsiang-Yi Hsu
Keyword(s):  
Land Use ◽  
Surface Temperature ◽  
Paddy Field ◽  
Research Area ◽  
Paddy Fields ◽  
Cooling Effect ◽  
Field Temperature ◽  
Bare Land ◽  
The Face ◽  
The Difference

In the face of climate change, extreme climates are becoming more frequent. There were severe droughts in Taiwan in 2020, 2014–2015, and 2002. In these years, the paddy fields were kept fallow to save water and transfer agricultural water to non-agricultural use. On the other hand, with global warming, the existence of paddy fields may be one of the natural solutions to regional temperature mitigation. This study used remote sensing to quantify the difference in temperature between paddy fields and urban areas. The result of overall surface temperature deductive analysis revealed that the temperature in the whole Taoyuan research area was 1.2 °C higher in 2002 than in 2003 because of fallowing of the paddy field, while in the Hsinchu research area, it was 1.5 °C higher in 2002 than in 2003, due to the same reason described above. In terms of the difference in land use, for the Hsinchu research area, the surface temperature deductive result showed that the average paddy field temperature in 2002 was 22.3 °C (sample area average), which was 7.7 °C lower than that of the building and road point and 4.3 °C lower than that of the bare land point. The average paddy field temperature in 2003 was 19.2 °C (sample area average), which was 10.1 °C lower than that of the building and road point and 8.3 °C lower than that of the bare land point. Then this study evaluated the economic valuation of the paddy field cooling effect using the contingent valuation method. Through the paddy field cooling effect and in the face of worsening extreme global climate, the willingness to pay (WTP) of the respondents in Taiwan for a decrease of 1 °C with regard to the regional microclimate was evaluated. It was found that people in Taiwan are willing to pay an extra 8.89 USD/per kg rice/year for the paddy for a decrease in temperature by 1 °C in the regional microclimate due to the paddy field. Furthermore, this study applied the benefits transfer method to evaluate the value of a decrease of 1 °C in the regional microclimate in Taiwan. The value of a decrease of 1 °C in the regional microclimate in Taiwan is 9,693,144,279 USD/year. In this regard, the economic value of 1 °C must not be underestimated. In conclusion, more caution is needed while making decisions to change the land use of paddy fields to other land uses.

scholarly journals Ce-Bearing FeSi Alloy Inoculation of Electrically Melted, Low Sulphur Grey Cast Irons for Thin Wall Castings

Metals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1122
Author(s):  
Irina Varvara Balkan ◽  
Iulian Riposan
Keyword(s):  
Wall Thickness ◽  
Structural Characteristics ◽  
Cooling Curve ◽  
Thin Wall ◽  
Cast Irons ◽  
Iron Castings ◽  
Grey Cast ◽  
The Difference ◽  
Thermal Cooling ◽  
Fesi Alloy

Electrically melted and over-heated (>1500 °C) grey cast iron at less than 0.04%S, as commonly used, solidifies large amounts of carbides and/or undercooled graphite, especially in thin wall castings; this is necessary to achieve a stronger inoculation. The efficiency of Ce-bearing FeSi alloy is tested for lower ladle addition rates (0.15 and 0.25 wt.%), compared to the base and conventional inoculated iron (Ba,Ca-bearing FeSi alloy). The present work explores chill and associated structures in hypoeutectic grey iron (3.6–3.8%CE, 0.02%S, (%Mn) × (%S) = 0.013–0.016, Alres < 0.002%), in wedge castings W1, W2 and W3 (ASTM A 367, furan resin sand mould), at a lower cooling modulus (1.1–3.5 mm) that is typically used to control the quality of thin wall iron castings. Relatively clear and total chill well correlated with the standard thermal (cooling curve) analysis parameters and structural characteristics in wedge castings, at different wall thickness, displayed as the carbides/graphite ratio and presence of undercooled graphite morphologies. The difference in effects of the two inoculants addition is seen as the ability to decrease the amount of carbides and undercooled graphite, with Ce-bearing FeSi alloy outperforming the conventional inoculant, especially as the wall thickness decreased. It appears that Ce-bearing FeSi alloy could be a solution for low sulphur, electric melt, thin wall iron castings production.

scholarly journals Can an Earth System Model simulate better climate change at mid-Holocene than an AOGCM? A comparison study of MIROC-ESM and MIROC3

2013 ◽  
Vol 9 (4) ◽  
pp. 1519-1542 ◽  
Author(s):  
R. Ohgaito ◽  
T. Sueyoshi ◽  
A. Abe-Ouchi ◽  
T. Hajima ◽  
S. Watanabe ◽  
...  
Keyword(s):  
Climate Change ◽  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Earth System Model ◽  
Sea Surface ◽  
System Model ◽  
Earth System ◽  
Intercomparison Project ◽  
The Difference ◽  
Precipitation Enhancement

Abstract. The importance of evaluating models through paleoclimate simulations is becoming more recognized in efforts to improve climate projection. To evaluate an integrated Earth System Model, MIROC-ESM, we performed simulations in time-slice experiments for the mid-Holocene (6000 yr before present, 6 ka) and preindustrial (1850 AD, 0 ka) periods under the protocol of the Coupled Model Intercomparison Project 5/Paleoclimate Modelling Intercomparison Project 3. We first give an overview of the simulated global climates by comparing with simulations using a previous version of the MIROC model (MIROC3), which is an atmosphere–ocean coupled general circulation model. We then comprehensively discuss various aspects of climate change with 6 ka forcing and how the differences in the models can affect the results. We also discuss the representation of the precipitation enhancement at 6 ka over northern Africa. The precipitation enhancement at 6 ka over northern Africa according to MIROC-ESM does not differ greatly from that obtained with MIROC3, which means that newly developed components such as dynamic vegetation and improvements in the atmospheric processes do not have significant impacts on the representation of the 6 ka monsoon change suggested by proxy records. Although there is no drastic difference between the African monsoon representations of the two models, there are small but significant differences in the precipitation enhancement over the Sahara in early summer, which can be related to the representation of the sea surface temperature rather than the vegetation coupling in MIROC-ESM. Because the oceanic parts of the two models are identical, the difference in the sea surface temperature change is ultimately attributed to the difference in the atmospheric and/or land modules, and possibly the difference in the representation of low-level clouds.

An Experience of Ageing on XLPE Insulation

2013 ◽  
Vol 64 (4) ◽  
Author(s):  
W. G. Ariastina ◽  
A. I. Weking ◽  
I. N. S. Kumara ◽  
I. A. D. Giriantari ◽  
I. N. Sugiarta
Keyword(s):  
Surface Temperature ◽  
Insulation Degradation ◽  
Maintenance Work ◽  
Conductor Temperature ◽  
Potential Losses ◽  
Distribution Feeder ◽  
The Difference ◽  
Post Insulator ◽  
Xlpe Insulation

A case study of ageing on XLPE conductor insulation of 20kV primary distribution feeder is presented in this paper. The insulation degradation mainly occurred around conductor tie where the conductor is attached to the post insulator. A section of distribution feeder with defects on the conductor insulation has been examined for this study. Potential losses due to presence of discharges have been investigated by measuring the difference current at locations of the affected conductor. Temperature measurements of the insulation surface have also been carried out. Provisional maintenance procedures were introduced to eliminate the discharges. Measurements of current and surface temperature were repeated nine months after completion of the maintenance work. Results indicated that the discharges have been completely disappeared.

Surface Temperature Field Statistics at an Air/Water Interface for Grid-Generated Sub-Surface Turbulence

2002 ◽  
Author(s):  
Karen A. Flack ◽  
Geoffrey B. Smith
Keyword(s):  
Surface Temperature ◽  
Infrared Camera ◽  
Temperature Fields ◽  
Interface Temperature ◽  
Water Interface ◽  
Bulk Fluid ◽  
Air Water Interface ◽  
Evaporative Convection ◽  
The Difference ◽  
Oscillation Frequencies

Surface temperature fields and statistics are presented for the case of sub-surface grid-generated turbulence impacting an air/water interface. Temperature measurements are obtained with an infrared camera, sensitive in the 3–5 micron wavelength range. Results indicate that increased grid oscillation frequencies, and shallower grid depths, lead to increased surface mixing, yielding lower values of RMS temperature. Non-dimensionalization of the RMS temperatures using the difference in the average surface and the bulk fluid temperatures, collapses the data obtained for different grid depths and oscillation frequencies. This scaling is related to the thermal boundary layer thickness. The results are compared to the baseline case of turbulence due to evaporative convection without an oscillating grid.

scholarly journals Data Mining Methods for Prediction of Multi-Component Al-Si Alloy Properties Based on Cooling Curves

2019 ◽  
Vol 28 (12) ◽  
pp. 7431-7444 ◽  
Author(s):  
Krzysztof Regulski ◽  
Dorota Wilk-Kołodziejczyk ◽  
Tomasz Szymczak ◽  
Grzegorz Gumienny ◽  
Zenon Pirowski ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Data Mining ◽  
Strength Properties ◽  
Cooling Curve ◽  
Cooling Curves ◽  
Alloying Additives ◽  
Statistical Relationships ◽  
Alloy Properties ◽  
Short Time ◽  
The Impact

AbstractThe paper concerns the mechanical properties of hypoeutectic Al-Si alloy (silumin) with the addition of Cr, Mo, V and W. Changes in microstructure under the impact of these elements result in a change in the mechanical properties. Crystallization of Al-Si alloys determines grain size reduction, which causes a significant increase in their strength properties. Crystallization subjected to modifications through the influence of alloying additives can be described by the cooling curve run. Statistical relationships between the characteristic values of cooling curves and mechanical properties are investigated with data mining techniques of regression, especially regression trees. Such knowledge could provide an ability of a property prediction on the basis of cooling curves in terms of the benefits of a short time of the curve registration.

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