Temperature strongly affects the conversion efficiency, local reactivity, and particle stabilization of the reactions, particularly at high temperature. This study integrated infrared thermography ...with a high-temperature hot stage reactor to develop a methodology of continuous temperature measurement for a single particle reaction at high temperatures. The external optical transmission transmittance and temperature field core were corrected, and the relationship between the measured temperature (Tr) and true temperature (T0) was obtained by adjusting the sample emissivity. Sample temperature with known emissivity at elevated temperature was measured with 1% deviation. The instantaneous temperature measurement for the gasification process was carried out and the overall emissivities of coal particles were corrected. Temperature distribution and variation on the coal particle surface during the gasification process were further obtained and consistent with the previous research results. The proposed online temperature measurement method provides a new approach for gaining insights into particle reaction states.
•Established online high-temperature measurement system for millimeter particle.•Algorithmic relationship between measured and true temperature was obtained.•In situ measurement of temperature distribution was recorded.•<8 K repeatability deviation for reaction temperature measurement.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Detailed assessment of small‐scale heterogeneity in local surface water balance is essential to accurate estimation of evapotranspiration in semiarid climates. However, meteorological approaches are ...often impractical to implement in sites with sparse and diverse vegetation composition, especially with seasonally variable leaf canopy features. Ground‐based infrared thermometry (TIR) provides spatially and temporally continuous resolution of surface skin temperature that can be directly related to the land surface energy balance. We made repeated measurements with a portable TIR camera to capture seasonal replicates for patch scale heat images for four sagebrush communities. The heat images near peak foliage and near the end of the growing season were compared by computation of surface energy fluxes from TIR sensing to surface energy balance (SEB) and Bowen ratio (BR). Estimates of sensible (H) and latent heat flux (LE) were evaluated with eddy covariance measurements to disaggregate the expression of seasonal phenology of sagebrush species across wetness and elevation. Estimations showed reasonable agreement with ground‐based LE observations for most cases (r2 = 0.59–0.76 for SEB and 0.22–0.72 for BR; root mean squared error = 73.4–106.4 W m−2 for SEB and 109.9–204.0 W m−2 for BR). Predictability declined as the fraction of senescent foliage increased in dry conditions. The field trials suggest the methods have the potential for monitoring land surface energy fluxes and plant health at a very fine spatial scale. The ability to partition heat fluxes from various plant communities over a range of moisture availability will provide valuable information associated with the consumptive water use and phenological processes in the semiarid West.
Ground‐based thermal infrared (TIR) temperature can predict spatio‐temporally continuous land surface energy balance. Proposed TIR methods showed good agreement with ground‐based eddy covariance observations in turbulent heat fluxes for most cases. Predictability declined substantially as the fraction of senescent foliage increased in dry conditions.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
•Nitrogen (N) and irrigation management are critical in the production of durum wheat.•A 2-year study in Arizona USA assessed N fertilizer and irrigation in durum wheat.•Recovery efficiency of added ...N was high in this system at greater than 70%.•Grain N was maximum at a lower water level (50% of full irrigation).•Optimal grain yields and grain protein are achievable.
Nitrogen and irrigation management are crucial in the production of high protein irrigated durum wheat (Triticum durum Desf.) in arid regions. However, as the availability of irrigation water decreases and potential costs and regulation of nitrogen (N) increase, there is a need to better understand how irrigation levels interacts with N fertilizer rates. A two-year field experiment was conducted in Maricopa, Arizona USA on a Casa Grande sandy loam to assess effects of N fertilizer and irrigation rates on grain yield, grain N, canopy temperatures yellow berry, and N use efficiency. Five rates of N fertilizer as urea ammonium nitrate (0, 84, 168, 252, and 336kgNha−1) were applied in three equal splits at Zadoks stages 30, 32, and 39. Ten un-randomized, sequential rates of irrigation ranging from 0.35 to 1.14 fraction of a non-deficit base irrigation treatment (maintained >45% soil water depletion) were applied by sequentially varying the nozzles in a gradient in an overhead sprinkler system. Irrigation plus rain ranged from 230 to 660mm in the first season, and 180 to 600mm in the second season. Grain yield was maximum in 2013 at the 252kgNha−1 fertilizer rate and at the 10th water level (1.14 irrigation), and between 168kg and 252kgNha−1at the 8th water level (1.0 irrigation) in 2014. The maximum grain yield of 7500kgha−1 in 2013 was reduced to 5000kgha−1 in 2014 due to a warmer, shorter growing season. Economic optimum N rate was at water level 8 both years (196 and 138kgNha−1 in 2013, and 2014, respectively). Recovery efficiency of added N was high in this system (i.e., >70%) at N fertilizer and water levels that maximized biomass and grain yields. Grain N was maximum at a lower water level (level 3 or 0.50–0.54 irrigation), was positively affected by N fertilizer rate, and was negatively related to yellow berry incidence. Canopy temperature minus air temperature values decreased linearly with increasing irrigation level. Nitrogen fertilizer applications reduced canopy temperature when water levels >0.54 and 0.69 irrigation fraction in 2013, and 2014, respectively. The study results suggested that canopy temperature and weather data that reflects the grain-filling period could be used to improve irrigation and N management, respectively. In short, irrigated durum wheat growers on this soil would achieve the economically optimum grain yield, with the least risk of yield or protein reduction, by applying 200kgNha−1 at the base irrigation level which maintains root zone soil moisture depletion below 45%.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
The heat transfer mechanisms of nucleate boiling are associated with how the liquid–vapor phase and the surface temperature are distributed and interact beneath a single bubble on a heated surface. A ...comparative analysis of the hydrodynamic and thermal behavior of a single bubble may contribute greatly to the understanding of nucleate boiling heat transfer. In this paper, a technique to simultaneously measure the liquid–vapor phase boundary, temperature distribution, and heat transfer distribution at a boiling surface is described. The technique is fully synchronized in time and spatially resolved, and is applied to explore single-bubble nucleate boiling phenomena in a pool of water subcooled by 3°C under atmospheric pressure. The temperature and heat flux distributions at the boiling surface are quantitatively interpreted in relation to the distribution and dynamics of the dry and wet areas, the triple contact line, and the microlayer underneath the single bubble. The results show that intensive wall heat transfer during single-bubble nucleate boiling exactly corresponds to the extended microlayer region. However, the overall contribution of the microlayer evaporation to the growth of a bubble is relatively small, and amounts to less than 17% of the total heat transport.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
•Mechanisms of boiling heat transfer enhancement by a surfactant were investigated.•Wall temperature was visualized at 3000 fps using a high-speed infrared camera.•Increase in microlayer area ...resulted in boiling heat transfer enhancement.•Microlayer evaporation contributed most to wall heat transfer.•Depletion of macrolayer beneath mushroom bubble led to a large dry surface.
It is well known that the addition of a surfactant to water as a boiling medium enhances its boiling heat transfer coefficient (HTC). The mechanisms of boiling heat transfer enhancement by adding a nonionic surfactant, which remain unclear, were explored in this study by visualizing the distributions of the temperature and heat transfer on the wall surface using a high-speed infrared camera. Heat flux partitioning, which partitions the heat transfer distribution into various fundamental heat transfer processes, demonstrated that the increase in the area of the microlayer region having the highest HTC enhances the heat transfer. The addition of surfactant softens the bubbles (reduces the surface tension) and suppresses their coalescence, thereby increasing the area occupied by the microlayer on the wall. Furthermore, the formation of the microlayer via the sliding motion of primary bubbles suppressed the formation of a dry surface. The contribution of microlayer evaporation to the overall wall heat transfer increased as the area coverage ratio of the microlayer increased, and unlike in pure water boiling, microlayer evaporation dominated the wall heat transfer over a wide range of heat flux conditions during surfactant solution boiling. In the high heat flux region, bubble coalescence was frequently observed even in the surfactant solution, and a macrolayer was formed at the bottom of mushroom bubbles. In the heat flux region above 0.9 MW/m2, a large dry surface was generated at the bottom of the mushroom bubbles due to the depletion of the macrolayer that covered a wide area of the wall surface.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Background/Need
Postoperative flap perfusion assessment methods still rely on the evaluation of traditional clinical indicators, which have the disadvantage of being subjective and burdensome.
...Methodology
This study describes a self-designed infrared wireless thermometer for flap blood supply monitoring and evaluates its efficacy in the postoperative monitoring of 40 free flaps.
Device Description
The device consists of multiple temperature and humidity modules as well as a wireless module, which has the advantages of low cost and continuous remote monitoring.
Preliminary results
The alarm time of the wireless infrared thermometer was 30.5 ± 3.1 hours, and the clinical observation reported 41.7 ± 13.6 hours.
Current status
In future studies, the device will be tested on different types of flaps in a porcine model.
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NUK, OILJ, SAZU, UKNU, UL, UM, UPUK
•Dynamic prescription maps were developed from plant canopy and weather data.•Continuous plant measurements were made with a wireless sensor network system.•Prescription map development was ...automated.•Site-specific irrigation was accomplished with a plant feedback system.
A prescription map is a set of instructions that controls a variable rate irrigation (VRI) system. These maps, which may be based on prior yield, soil texture, topography, or soil electrical conductivity data, are often manually applied at the beginning of an irrigation season and remain static. The problem with static prescription maps is that they ignore spatiotemporal changes in crop water status. In a two-year study (2012 and 2013), a plant feedback system, including a wireless sensor network of infrared thermometers (IRTs), was used to develop dynamic prescription maps to accomplish adaptive irrigation scheduling for cotton (Gossypium hirsutum L.). One-half of a center pivot field was divided into manually and plant feedback-controlled irrigation treatment plots. Irrigation treatments were at three levels, 75, 50 and 25 percent of full as defined by either replenishment of crop water use to field capacity or by the equivalent threshold of the IRT sensed crop water stress. The system accepted user input to control irrigation for the manual treatment plots (I75M, I50M, and I25M), and calculated and compared a thermal stress index for each plant feedback-controlled treatment plot (I75C, I50C and I25C) with a pre-determined threshold for automated irrigation scheduling. The effectiveness of the plant feedback irrigation scheduling system was evaluated by comparing measured lint yield, crop water use (ETc), and water use efficiency (WUE) with the manually scheduled treatment plots. Results for both years indicated that average lint yields were similar between the manual and plant feedback-control plots at the I75 level (181 and 182gm−2, respectively, in 2012; 115 and 103gm−2, respectively, in 2013) and I50 level (146 and 164gm−2, respectively, in 2012; 95 and 117gm−2, respectively, in 2013). At the I25 level, average lint yield was significantly greater for the plant feedback-compared with the manual-control treatment plots (142gm−2 and 92gm−2, respectively), but the mean amount of irrigation was twice that of the manual-control plots. Mean water use efficiencies (WUE) within the same irrigation treatment levels were similar between methods. Importantly, the automatic plant feedback system did not require the time consuming and expensive manual reading of neutron probe access tubes that was required to schedule the manual treatments. These results demonstrate that the integration of a plant feedback system with a commercial VRI system could be used to control site-specific irrigation management for cotton at higher irrigation treatment levels, i.e., I75 percent and I50 percent of full. Such a system can facilitate the use of a VRI system by automating prescription map coding and providing dynamic irrigation control instructions to meet variable crop water needs throughout the irrigation season. As of yet, further research is required to maintain automatic deficit irrigation at a level equivalent to 25 percent replenishment of crop water use relative to field capacity.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
•High-resolution infrared investigations of subcooled flow boiling and CHF.•Direct measurement of fundamental boiling parameters and heat flux partitioning.
We present an experimental methodology ...that enables accurate measurement of fundamental subcooled flow boiling quantities, such as nucleation site density, bubble growth and wait time, and bubble departure diameter, up to the Critical Heat Flux (CHF) limit. The methodology is based on high-speed video and high-speed InfraRed (IR) diagnostics, combined with advanced post-processing techniques developed in-house. It also provides hitherto unavailable direct estimates of the individual terms of wall heat flux partitioning in subcooled flow boiling; such information is crucially relevant to the validation of the latest mechanistic flow boiling heat transfer and CHF models. Experiments were performed using deionized (DI) water, on a rectangular cross-section channel (3 × 1 cm2), at atmospheric pressure and 10 °C of subcooling, for three mass fluxes (500 kg/m2/s, 750 kg/m2/s, and 1000 kg/m2/s). For each set of operating conditions, the average heat flux was escalated from single-phase forced convection up to the occurrence of CHF, and all boiling parameters were recorded at each heat flux. The trends of measured wait time, growth time and bubble departure diameter were successfully captured by mechanistic models developed or co-developed by the authors. Measurements of the wall heat flux partitioning have revealed that the contribution of microlayer evaporation increases monotonically with the increase of the average heat flux, due to the increase of nucleation site density and bubble departure frequency. However, for our specific heater and operating conditions, the contribution of the microlayer evaporation barely exceeds 50% of the total heat flux, right before CHF.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
•High vapor pressure deficit severely decreases holm oak stomatal conductance.•Atmospheric and edaphic water stress additively reduce transpiration.•Mediterranean summers restrict maximum carbon gain ...to a short environmental window.•Vapor pressure deficit modulate plant physiological performance and distribution.
High rates of vapor pressure deficit (VPD) can severely decrease plant productivity by reducing stomatal conductance, which might be exacerbated during Mediterranean summers due to soil water deficit. In this study, we monitored the response of holm oak, the archetype of Mediterranean trees, to changes in VPD during a summer drought period to evaluate the effects and consequences on gas exchange of the two water stresses (atmospheric and soil). Measurements were performed on trees growing in an experimental plantation over two summers with moderate drought stress by using three different methods: at the leaf level with an infrared gas analyzer, using a whole-plant chamber for short-term monitoring at the tree level, and measuring the canopy temperature for long-term monitoring. The three methods provided negative relationships between leaf conductance and VPD but with discrepancies probably associated with the measurement scale. Overall, the results showed that atmospheric and soil water stress had an additive effect. Under well-watered conditions, an increase in VPD was partially compensated by a reduction in stomatal conductance, resulting in a slight increase in the transpiration rates. With soil water deficit, the response to VPD resulted in a further decrease in stomatal conductance, reducing transpiration as a water saving strategy. The decrease in conductance in response to VPD was transitory, recovering to initial values as soon as the VPD decreased, both under well-watered and drought conditions. Due to this high sensitivity to atmospheric drought, the maximum carbon gain rates of holm oak were restricted to a short environmental window, which might modulate its physiological performance and natural distribution.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Smartphones have several advantages over specialist monitoring systems including ubiquity, price, and ease of implementing updates. Thermal imaging can be used to assess plant water status and allow ...more informed irrigation decisions; unfortunately, this technique has not been widely adopted due to the high cost of equipment and the lack of a system to provide analysis and results in real-time. Several inexpensive thermal cameras that connect to smartphones have recently been released and one of these (FLIR One) was evaluated as part of a system to assess grapevine water status. Irrigation treatments were established on Cabernet Sauvignon and Chardonnay vines in an arid region. Thermal images were taken from the shaded side of the grapevine canopy and software was developed to automatically determine the temperature of the canopy and artificial reference leaves. The temperature readings and metrological inputs were used to calculate five indices of water status including the Crop Water Stress Index (CWSI) and the stomatal conductance index. The best performing was the CWSI, which does not require input from a weather station. Over 30 days of assessment, and a range of irrigation levels, measurements collected with the thermal camera were correlated with stem water potential (R2 = 0.61) and stomatal conductance (R2 = 0.74). Windy conditions appeared to be the major cause of variation between CWSI and stomatal conductance. Inexpensive thermal cameras have the potential to be an easy and accessible tool for the assessment of plant water status and to make better irrigation decisions.
•A thermal camera and smartphone based system to assess water status is presented.•An artificial reference surface and shaded canopy temperature are used as inputs.•Stomatal conductance and Crop Water Stress Index were closely correlated.•This is a promising system to aid irrigation scheduling.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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