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Kong Q, Shibuta Y. Predicting materials properties with generative models: applying generative adversarial networks for heat flux generation. J Phys Condens Matter 2024; 36:195901. [PMID: 38306716 DOI: 10.1088/1361-648x/ad258b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Accepted: 02/01/2024] [Indexed: 02/04/2024]
Abstract
In the realm of materials science, the integration of machine learning techniques has ushered in a transformative era. This study delves into the innovative application of generative adversarial networks (GANs) for generating heat flux data, a pivotal step in predicting lattice thermal conductivity within metallic materials. Leveraging GANs, this research explores the generation of meaningful heat flux data, which has a high degree of similarity with that calculated by molecular dynamics simulations. This study demonstrates the potential of artificial intelligence (AI) in understanding the complex physical meaning of data in materials science. By harnessing the power of such AI to generate data that is previously attainable only through experiments or simulations, new opportunities arise for exploring and predicting properties of materials.
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Affiliation(s)
- Qi Kong
- Department of Materials Engineering, The University of Tokyo, Tokyo, Japan
| | - Yasushi Shibuta
- Department of Materials Engineering, The University of Tokyo, Tokyo, Japan
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Blokker T, Bucher E, Steiner T, Wehrlin JP. Effect of cold ambient temperature on heat flux, skin temperature, and thermal sensation at different body parts in elite biathletes. Front Sports Act Living 2022; 4:966203. [PMID: 36406769 PMCID: PMC9666787 DOI: 10.3389/fspor.2022.966203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Accepted: 10/07/2022] [Indexed: 01/25/2023] Open
Abstract
INTRODUCTION When exercising in the cold, optimizing thermoregulation is essential to maintain performance. However, no study has investigated thermal parameters with wearable-based measurements in a field setting among elite Nordic skiers. Therefore, this study aimed to assess the thermal response and sensation measured at different body parts during exercise in a cold environment in biathletes. METHODS Thirteen Swiss national team biathletes (6 females, 7 males) performed two skiing bouts in the skating technique on two consecutive days (ambient temperature: -3.74 ± 2.32 °C) at 78 ± 4% of maximal heart rate. Heat flux (HF), core (Tcore) and skin (Tskin) temperature were measured with sensors placed on the thigh, back, anterior and lateral thorax. Thermal sensation (TS) was assessed three times for different body parts: in protective winter clothing, in a race suit before (PRE) and after exercise (POST). RESULTS HF demonstrated differences (p < 0.001) between sensor locations, with the thigh showing the highest heat loss (344 ± 37 kJ/m2), followed by the back (269 ± 6 kJ/m2), the lateral thorax (220 ± 47 kJ/m2), and the anterior thorax (192 ± 37 kJ/m2). Tcore increased (p < 0.001). Tskin decreased for all body parts (p < 0.001). Thigh Tskin decreased more than for other body parts (p < 0.001). From PRE to POST, TS of the hands decreased (p < 0.01). CONCLUSION Biathletes skiing in a race suit at moderate intensity experience significant heat loss and a large drop in Tskin, particularly at the quadriceps muscle. To support the optimal functioning of working muscles, body-part dependent differences in the thermal response should be considered for clothing strategy and for race suit design.
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Nguyen T, Dang T. The Effect of Fin Shape on the Heat Transfer and the Solution Time of a Microchannel Evaporator in a CO 2 Air Conditioning System-A Numerical Investigation. Micromachines (Basel) 2022; 13:1648. [PMID: 36295999 PMCID: PMC9610599 DOI: 10.3390/mi13101648] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Revised: 08/29/2022] [Accepted: 09/27/2022] [Indexed: 06/16/2023]
Abstract
Numerical simulations on the fin shape of a microchannel evaporator in a CO2 air conditioning system were performed at the inlet evaporative temperature of 10 °C and the vapor quality of 0.61. Two types of fin shapes were dealt with: the straight fins and V-fins. The numerical results were verified by the experimental data. For the system under consideration and for the same heat transfer area and the heat transfer coefficient for the air side in the microchannel evaporator, the effect of the fin shape on the heat transfer was not different; however, the solution time and the physical memory for the straight fins were 1.3 and 1.45 times compared with the V-fins, respectively. Therefore, the V-fin shape should be used for numerical simulation to compare it with the straight fin shape. In this study, the evaporation of the refrigerant in the microchannel evaporator took place in four passes. The normal heat flux from the air through the fins and tubes was almost reached at 1550 W/m2 at the evaporative temperature of 10 °C. The results obtained from the experimental data were in good agreement with those obtained from the numerical results, with a deviation of less than 10%.
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Pastorino C, Urrutia I, Fiora M, Condado F. Heat flow through a liquid-vapor interface in a nano-channel: the effect of end-grafting polymers on a wall. J Phys Condens Matter 2022; 34:344004. [PMID: 35688142 DOI: 10.1088/1361-648x/ac77ce] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Accepted: 06/10/2022] [Indexed: 06/15/2023]
Abstract
Heat transfer through a liquid-vapor interface is a complex phenomenon and crucially relevant in heat-removal and cryogenic applications. The physical coupling among confining walls, liquid and vapor phases is very important for controlling or improving cooling rates or condensation efficiency. Surface modification is a promising route, which has been explored to taylor the heat transfer through confined two-phase systems. We use coarse-grained molecular-dynamics simulations to study the heat transfer through a nano-confined liquid-vapor interface as a function of fluid filling. We set up a stationary heat flow through a liquid-vapor interface, stabilized with the liquid in contact with a colder wall and a vapor in contact with a hotter wall. For these physical conditions, we perform extensive simulations by progressively increasing the number of fluid particles, i.e. the channel filling, and measure the fluid distribution in the channel, density, pressure and temperature profiles We also compare the heat flux behavior between a bare-surfaces nano-channel and others where the hot surface was coated with end-grafted polymers, with different wetting affinities and bending properties. We take extreme cases of polymer properties to obtain a general picture of the polymer effect on the heat transfer, as compared with the bare surfaces. We find that walls covered by end-grafted solvophylic polymers change the heat flux by a factor of 6, as compared with bare walls, if the liquid phase is in contact with the polymers. Once the liquid wets the coated wall, the improve on heat flux is smaller and dominated by the grafting density. We also find that for a wall coated with stiff polymers, the jump in heat flux takes place at a significantly lower channel filling, when the polymers' free ends interact with the liquid surface. Interestingly, the morphology of the polymers induces a 'liquid bridge' between the liquid phase and the hot wall, through which heat is transported with high (liquid-like) thermal conductivity.
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Affiliation(s)
- Claudio Pastorino
- Departamento de Física de la Materia Condensada, Centro Atómico Constituyentes, CNEA, Av. Gral. Paz 1499, San Martín, Buenos Aires, 1650, Argentina
- Instituto de Nanociencia y Nanotecnología, CONICET-CNEA, CAC
| | - Ignacio Urrutia
- Departamento de Física de la Materia Condensada, Centro Atómico Constituyentes, CNEA, Av. Gral. Paz 1499, San Martín, Buenos Aires, 1650, Argentina
- Instituto de Nanociencia y Nanotecnología, CONICET-CNEA, CAC
| | - María Fiora
- INTI-Micro y Nanotecnologías, Instituto Nacional de Tecnología Industrial, Av. Gral. Paz 5445, B1650WAB San Martín, Argentina
| | - Federico Condado
- Departamento de Física de la Materia Condensada, Centro Atómico Constituyentes, CNEA, Av. Gral. Paz 1499, San Martín, Buenos Aires, 1650, Argentina
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Ajčević M, Buoite Stella A, Furlanis G, Caruso P, Naccarato M, Accardo A, Manganotti P. A Novel Non-Invasive Thermometer for Continuous Core Body Temperature: Comparison with Tympanic Temperature in an Acute Stroke Clinical Setting. Sensors (Basel) 2022; 22:s22134760. [PMID: 35808257 PMCID: PMC9269248 DOI: 10.3390/s22134760] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Revised: 06/17/2022] [Accepted: 06/22/2022] [Indexed: 02/04/2023]
Abstract
There is a growing research interest in wireless non-invasive solutions for core temperature estimation and their application in clinical settings. This study aimed to investigate the use of a novel wireless non-invasive heat flux-based thermometer in acute stroke patients admitted to a stroke unit and compare the measurements with the currently used infrared (IR) tympanic temperature readings. The study encompassed 30 acute ischemic stroke patients who underwent continuous measurement (Tcore) with the novel wearable non-invasive CORE device. Paired measurements of Tcore and tympanic temperature (Ttym) by using a standard IR-device were performed 3−5 times/day, yielding a total of 305 measurements. The predicted core temperatures (Tcore) were significantly correlated with Ttym (r = 0.89, p < 0.001). The comparison of the Tcore and Ttym measurements by Bland−Altman analysis showed a good agreement between them, with a low mean difference of 0.11 ± 0.34 °C, and no proportional bias was observed (B = −0.003, p = 0.923). The Tcore measurements correctly predicted the presence or absence of Ttym hyperthermia or fever in 94.1% and 97.4% of cases, respectively. Temperature monitoring with a novel wireless non-invasive heat flux-based thermometer could be a reliable alternative to the Ttym method for assessing core temperature in acute ischemic stroke patients.
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Affiliation(s)
- Miloš Ajčević
- Clinical Unit of Neurology, Department of Medicine, Surgery and Health Sciences, Cattinara University Hospital ASUGI, University of Trieste, Strada di Fiume, 447-34149 Trieste, Italy; (M.A.); (G.F.); (P.C.); (M.N.); (P.M.)
- Department of Engineering and Architecture, University of Trieste, Via A. Valerio, 10-34127 Trieste, Italy;
| | - Alex Buoite Stella
- Clinical Unit of Neurology, Department of Medicine, Surgery and Health Sciences, Cattinara University Hospital ASUGI, University of Trieste, Strada di Fiume, 447-34149 Trieste, Italy; (M.A.); (G.F.); (P.C.); (M.N.); (P.M.)
- Correspondence: ; Tel.: +39-040-399-4075 (ext. 6582); Fax: +39-040-399-4284
| | - Giovanni Furlanis
- Clinical Unit of Neurology, Department of Medicine, Surgery and Health Sciences, Cattinara University Hospital ASUGI, University of Trieste, Strada di Fiume, 447-34149 Trieste, Italy; (M.A.); (G.F.); (P.C.); (M.N.); (P.M.)
| | - Paola Caruso
- Clinical Unit of Neurology, Department of Medicine, Surgery and Health Sciences, Cattinara University Hospital ASUGI, University of Trieste, Strada di Fiume, 447-34149 Trieste, Italy; (M.A.); (G.F.); (P.C.); (M.N.); (P.M.)
| | - Marcello Naccarato
- Clinical Unit of Neurology, Department of Medicine, Surgery and Health Sciences, Cattinara University Hospital ASUGI, University of Trieste, Strada di Fiume, 447-34149 Trieste, Italy; (M.A.); (G.F.); (P.C.); (M.N.); (P.M.)
| | - Agostino Accardo
- Department of Engineering and Architecture, University of Trieste, Via A. Valerio, 10-34127 Trieste, Italy;
| | - Paolo Manganotti
- Clinical Unit of Neurology, Department of Medicine, Surgery and Health Sciences, Cattinara University Hospital ASUGI, University of Trieste, Strada di Fiume, 447-34149 Trieste, Italy; (M.A.); (G.F.); (P.C.); (M.N.); (P.M.)
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Zachar M, Čabalová I, Kačíková D, Zacharová L. The Effect of Heat Flux to the Fire-Technical and Chemical Properties of Spruce Wood ( Picea abies L.). Materials (Basel) 2021; 14:ma14174989. [PMID: 34501079 PMCID: PMC8434228 DOI: 10.3390/ma14174989] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 08/24/2021] [Accepted: 08/30/2021] [Indexed: 11/24/2022]
Abstract
The paper assesses the influence of the heat flux on spruce wood (Picea abies L.) behavior. The heat flux was performed at 15, 20, 25, and 30 kW·m−2. The fire-technical properties, such as the mass burning rate, charring thickness, charring rate, as well as the chemical composition (contents of the extractives, lignin, cellulose, holocellulose), of wood were determined. The highest burning rate of spruce wood of 0.32%·s−1 was reached at the heat flux of 30 kW·m−2. The charring rate ranged from 1.004 mm·min−1 (15 kW·m−2) to 2.016 mm·min−1 (30 kW·m−2). The proposed model of the charring process of spruce wood in time and appropriate thickness as a selected parameter is applicable in validation of the results of computer fire models in the design of fire protection of wooden buildings. The decrease in the holocellulose content mostly caused by the degradation of hemicelluloses was observed during thermal loading. The biggest decrease in hemicelluloses (24.94%) was recorded in samples loaded at 30 kW·m−2. The contents of cellulose increased due to the structural changes (carbonization and crosslinking), the content of lignin increased as well due to its higher thermal stability compared to saccharides, as well as the resulting lignin condensation.
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Affiliation(s)
- Martin Zachar
- Department of Fire Protection, Faculty of Wood Sciences and Technology, Technical University in Zvolen, 960 01 Zvolen, Slovakia; (M.Z.); (D.K.)
| | - Iveta Čabalová
- Department of Chemistry and Chemical Technologies, Faculty of Wood Sciences and Technology, Technical University in Zvolen, 960 01 Zvolen, Slovakia
- Correspondence: ; Tel.: +421-455206375
| | - Danica Kačíková
- Department of Fire Protection, Faculty of Wood Sciences and Technology, Technical University in Zvolen, 960 01 Zvolen, Slovakia; (M.Z.); (D.K.)
| | - Lucia Zacharová
- National Forest Centre, Forest Research Institute, 960 01 Zvolen, Slovakia;
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Bierwisch C. Consistent Thermo-Capillarity and Thermal Boundary Conditions for Single-Phase Smoothed Particle Hydrodynamics. Materials (Basel) 2021; 14:4530. [PMID: 34443055 DOI: 10.3390/ma14164530] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Revised: 08/07/2021] [Accepted: 08/10/2021] [Indexed: 12/02/2022]
Abstract
A model for capillary phenomena including temperature-dependency and thermal boundary conditions is presented in the numerical framework of smoothed particle hydrodynamics (SPH). The model requires only a single fluid phase and is therefore computationally more efficient than surface tension schemes which need an explicit fluid-fluid or fluid-gas interface. The model makes use of a surface identification mechanism based on the SPH renormalization tensor. All relevant properties of the continuum surface force (CSF) based approach, i.e., the delta function, normal vector and curvature, are calculated in a consistent manner. The model is parametrized by physical material properties and is successfully validated by means of a large set of analytical test cases. The applicability of the proposed model to more complex scenarios is demonstrated.
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Corbett S, Gautam D, Lal S, Yu K, Balla N, Cunningham G, Razeeb KM, Enright R, McCloskey D. Electrodeposited Thin-Film Micro-Thermoelectric Coolers with Extreme Heat Flux Handling and Microsecond Time Response. ACS Appl Mater Interfaces 2021; 13:1773-1782. [PMID: 33393783 DOI: 10.1021/acsami.0c16614] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Thin-film thermoelectric coolers are emerging as a viable option for the on-chip temperature management of electronic and photonic integrated circuits. In this work, we demonstrate the record heat flux handling capability of electrodeposited Bi2Te3 films of 720(±60) W cm-2 at room temperature, achieved by careful control of the contact interfaces to reduce contact resistance. The characteristic parameters of a single leg thin-film devices were measured in situ, giving a Seebeck coefficient of S = -121(±6) μV K-1, thermal conductivity of κ = 0.85(±0.08) W m-1 K-1, electrical conductivity of σ = 5.2(±0.32) × 104 S m-1, and electrical contact resistivity of ∼10-11 Ω m2. These thermoelectric parameters lead to a material ZT = 0.26(±0.04), which, for our device structure, allowed a net cooling of ΔTmax = 4.4(±0.12) K. A response time of τ = 20 μs was measured experimentally. This work shows that with the correct treatment of contact interfaces, electrodeposited thin-film thermoelectrics can compete with more complicated and expensive technologies such as metal organic chemical vapor deposition (MOCVD) multilayers.
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Affiliation(s)
- Simon Corbett
- School of Physics, Trinity College, Dublin 2 D02 PN40, Ireland
| | - D Gautam
- Tyndall National Institute, University College Cork, Dyke Parade, Lee Maltings, Cork T12 R5CP, Ireland
| | - Swatchith Lal
- Tyndall National Institute, University College Cork, Dyke Parade, Lee Maltings, Cork T12 R5CP, Ireland
| | - Kenny Yu
- School of Physics, Trinity College, Dublin 2 D02 PN40, Ireland
- Thermal Management Research Group, Efficient Energy Transfer (ηET) Department, Nokia Bell Labs, Dublin D15 Y6NT, Ireland
| | - Naveen Balla
- AMBER Centre, CRANN Institute, Trinity College Dublin, Dublin 2 D02 PN40, Ireland
| | - Graeme Cunningham
- School of Physics, Trinity College, Dublin 2 D02 PN40, Ireland
- AMBER Centre, CRANN Institute, Trinity College Dublin, Dublin 2 D02 PN40, Ireland
| | - Kafil M Razeeb
- Tyndall National Institute, University College Cork, Dyke Parade, Lee Maltings, Cork T12 R5CP, Ireland
| | - Ryan Enright
- Thermal Management Research Group, Efficient Energy Transfer (ηET) Department, Nokia Bell Labs, Dublin D15 Y6NT, Ireland
| | - David McCloskey
- School of Physics, Trinity College, Dublin 2 D02 PN40, Ireland
- AMBER Centre, CRANN Institute, Trinity College Dublin, Dublin 2 D02 PN40, Ireland
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Genin A, Levy L, Sharon G, Raitsos DE, Diamant A. Rapid onsets of warming events trigger mass mortality of coral reef fish. Proc Natl Acad Sci U S A 2020; 117:25378-85. [PMID: 32958634 DOI: 10.1073/pnas.2009748117] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Our study reveals a hitherto overlooked ecological threat of climate change. Studies of warming events in the ocean have typically focused on the events' maximum temperature and duration as the cause of devastating disturbances in coral reefs, kelp forests, and rocky shores. In this study, however, we found that the rate of onset (Ronset), rather than the peak, was the likely trigger of mass mortality of coral reef fishes in the Red Sea. Following a steep rise in water temperature (4.2 °C in 2.5 d), thermally stressed fish belonging to dozens of species became fatally infected by Streptococcus iniae Piscivores and benthivores were disproportionately impacted whereas zooplanktivores were spared. Mortality rates peaked 2 wk later, coinciding with a second warming event with extreme Ronset The epizootic lasted ∼2 mo, extending beyond the warming events through the consumption of pathogen-laden carcasses by uninfected fish. The warming was widespread, with an evident decline in wind speed, barometric pressure, and latent heat flux. A reassessment of past reports suggests that steep Ronset was also the probable trigger of mass mortalities of wild fish elsewhere. If the ongoing increase in the frequency and intensity of marine heat waves is associated with a corresponding increase in the frequency of extreme Ronset, calamities inflicted on coral reefs by the warming oceans may extend far beyond coral bleaching.
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Guardia C, Barluenga G, Palomar I. PCM Cement-Lime Mortars for Enhanced Energy Efficiency of Multilayered Building Enclosures under Different Climatic Conditions. Materials (Basel) 2020; 13:ma13184043. [PMID: 32933062 PMCID: PMC7558161 DOI: 10.3390/ma13184043] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 09/08/2020] [Accepted: 09/10/2020] [Indexed: 11/16/2022]
Abstract
Phase change materials (PCMs) are promising materials for the energy efficiency improvement of building enclosures, due to their energy storage capacity. The thermal behaviour of a multi-layered building enclosure with five different compositions of PCM cement-lime mortars was evaluated under heating and cooling cycles. The behaviour of cement-lime mortars with 20% of microencapsulated PCM mixed with other additions, such as cellulose fibres and perlite, a lightweight aggregate (LWA), were studied under climate conditions of 15 °C-82% RH (cooling) and 30 °C-33% RH (heating) that were applied with a climatic chamber. Temperature and heat flux on both sides of the multi-layered enclosure were experimentally measured in laboratory tests. Temperature was also measured on both sides of the PCM cement-lime mortar layer. It was observed that the addition of the PCM cement-lime mortar layer delayed the heat flux through the enclosure. During a heating cycle, the incorporation of PCM delayed the arrival of the heat wave front by 30 min (8.1% compared to the reference mortar without PCM). The delay of the arrival of the heat wave front during the cooling cycle after adding PCM, compared to the reference mixture, reached 40.6% (130 min of delay). Furthermore, the incorporation of LWA in PCM cement-lime mortars also improved thermal insulation, further increasing energy efficiency of the building enclosure, and can be used not only for new buildings but also for energy rehabilitation of existing building enclosures.
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Graf A, Klosterhalfen A, Arriga N, Bernhofer C, Bogena H, Bornet F, Brüggemann N, Brümmer C, Buchmann N, Chi J, Chipeaux C, Cremonese E, Cuntz M, Dušek J, El-Madany TS, Fares S, Fischer M, Foltýnová L, Gharun M, Ghiasi S, Gielen B, Gottschalk P, Grünwald T, Heinemann G, Heinesch B, Heliasz M, Holst J, Hörtnagl L, Ibrom A, Ingwersen J, Jurasinski G, Klatt J, Knohl A, Koebsch F, Konopka J, Korkiakoski M, Kowalska N, Kremer P, Kruijt B, Lafont S, Léonard J, De Ligne A, Longdoz B, Loustau D, Magliulo V, Mammarella I, Manca G, Mauder M, Migliavacca M, Mölder M, Neirynck J, Ney P, Nilsson M, Paul-Limoges E, Peichl M, Pitacco A, Poyda A, Rebmann C, Roland M, Sachs T, Schmidt M, Schrader F, Siebicke L, Šigut L, Tuittila ES, Varlagin A, Vendrame N, Vincke C, Völksch I, Weber S, Wille C, Wizemann HD, Zeeman M, Vereecken H. Altered energy partitioning across terrestrial ecosystems in the European drought year 2018. Philos Trans R Soc Lond B Biol Sci 2020; 375:20190524. [PMID: 32892732 DOI: 10.1098/rstb.2019.0524] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Drought and heat events, such as the 2018 European drought, interact with the exchange of energy between the land surface and the atmosphere, potentially affecting albedo, sensible and latent heat fluxes, as well as CO2 exchange. Each of these quantities may aggravate or mitigate the drought, heat, their side effects on productivity, water scarcity and global warming. We used measurements of 56 eddy covariance sites across Europe to examine the response of fluxes to extreme drought prevailing most of the year 2018 and how the response differed across various ecosystem types (forests, grasslands, croplands and peatlands). Each component of the surface radiation and energy balance observed in 2018 was compared to available data per site during a reference period 2004-2017. Based on anomalies in precipitation and reference evapotranspiration, we classified 46 sites as drought affected. These received on average 9% more solar radiation and released 32% more sensible heat to the atmosphere compared to the mean of the reference period. In general, drought decreased net CO2 uptake by 17.8%, but did not significantly change net evapotranspiration. The response of these fluxes differed characteristically between ecosystems; in particular, the general increase in the evaporative index was strongest in peatlands and weakest in croplands. This article is part of the theme issue 'Impacts of the 2018 severe drought and heatwave in Europe: from site to continental scale'.
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Affiliation(s)
- Alexander Graf
- Institute of Bio- and Geosciences: Agrosphere (IBG3), Forschungszentrum Jülich, Wilhelm-Johnen-Straße, 52428 Jülich, Germany
| | - Anne Klosterhalfen
- Institute of Bio- and Geosciences: Agrosphere (IBG3), Forschungszentrum Jülich, Wilhelm-Johnen-Straße, 52428 Jülich, Germany.,Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Skogsmarksgränd 17, 90183 Umeå, Sweden
| | - Nicola Arriga
- European Commission, Joint Research Centre (JRC), Ispra, Italy
| | - Christian Bernhofer
- Chair of Meteorology, Technische Universität Dresden, Pienner Straße 23, 01737 Tharandt, Germany
| | - Heye Bogena
- Institute of Bio- and Geosciences: Agrosphere (IBG3), Forschungszentrum Jülich, Wilhelm-Johnen-Straße, 52428 Jülich, Germany
| | - Frédéric Bornet
- BioEcoAgro Joint Research Unit, INRAE, Université de Liège, Université de Lille, Université de Picardie Jules Verne, 02000 Barenton-Bugny, France
| | - Nicolas Brüggemann
- Institute of Bio- and Geosciences: Agrosphere (IBG3), Forschungszentrum Jülich, Wilhelm-Johnen-Straße, 52428 Jülich, Germany
| | - Christian Brümmer
- Institute of Climate-Smart Agriculture, Johann Heinrich von Thünen Institute, Bundesallee 65, 38116 Braunschweig, Germany
| | - Nina Buchmann
- Department of Environmental Systems Science, ETH Zurich, Universitätstraße 2, 8092 Zurich, Switzerland
| | - Jinshu Chi
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Skogsmarksgränd 17, 90183 Umeå, Sweden
| | | | - Edoardo Cremonese
- Climate Change Unit, Environmental Protection Agency of Aosta Valley, Italy
| | - Matthias Cuntz
- Unité mixte de Recherche Silva, Université de Lorraine, AgroParisTech, INRAE, UMR Silva, 54000 Nancy, France
| | - Jiří Dušek
- Department of Matter and Energy Fluxes, Global Change Research Institute of the Czech Academy of Sciences, Bělidla 986/4a, 60300 Brno, Czech Republic
| | - Tarek S El-Madany
- Department of Biogeochemical Integration, Max Planck Institute for Biogeochemistry, Hans-Knöll-Straße 10, 07745 Jena, Germany
| | - Silvano Fares
- National Research Council (NRC), Institute of Bioeconomy, Via dei Taurini 19, 00100 Rome, Italy
| | - Milan Fischer
- Department of Matter and Energy Fluxes, Global Change Research Institute of the Czech Academy of Sciences, Bělidla 986/4a, 60300 Brno, Czech Republic
| | - Lenka Foltýnová
- Department of Matter and Energy Fluxes, Global Change Research Institute of the Czech Academy of Sciences, Bělidla 986/4a, 60300 Brno, Czech Republic
| | - Mana Gharun
- Department of Environmental Systems Science, ETH Zurich, Universitätstraße 2, 8092 Zurich, Switzerland
| | - Shiva Ghiasi
- Department of Environmental Systems Science, ETH Zurich, Universitätstraße 2, 8092 Zurich, Switzerland
| | - Bert Gielen
- University of Antwerp, Plants and Ecosystems, Universiteitsplein 1, 2610 Wilrijk, Belgium
| | - Pia Gottschalk
- Remote Sensing and Geoinformatics, German Research Centre for Geosciences (GFZ), Telegrafenberg, 14473 Potsdam, Germany
| | - Thomas Grünwald
- Chair of Meteorology, Technische Universität Dresden, Pienner Straße 23, 01737 Tharandt, Germany
| | - Günther Heinemann
- Environmental Meteorology, University of Trier, Behringstraße 21, 54296 Trier, Germany
| | - Bernard Heinesch
- Terra Teaching and Research Centre, University of Liege - Gembloux Agro-Bio Tech, Avenue de la Faculté, 8, 5030 Gembloux, Belgium
| | - Michal Heliasz
- Department of Physical Geography and Ecosystem Science, Lund University, Sölvegatan 12, 22362 Lund, Sweden
| | - Jutta Holst
- Department of Physical Geography and Ecosystem Science, Lund University, Sölvegatan 12, 22362 Lund, Sweden
| | - Lukas Hörtnagl
- Department of Environmental Systems Science, ETH Zurich, Universitätstraße 2, 8092 Zurich, Switzerland
| | - Andreas Ibrom
- Department of Environmental Engineering, Technical University of Denmark (DTU), Bygningstorvet 115, 2800 Lyngby, Denmark
| | - Joachim Ingwersen
- Institute of Soil Science and Land Evaluation, University of Hohenheim, Emil-Wolff-Straße 27, 70599 Stuttgart, Germany
| | - Gerald Jurasinski
- Department for Landscape Ecology and Site Evaluation, University of Rostock, Justus von Liebig Weg 6, 18059 Rostock, Germany
| | - Janina Klatt
- Institute of Meteorology and Climate Research - Atmospheric Environmental Research, Karlsruhe Institute of Technology, Campus Alpin, Kreuzeckbahnstraße 19, 82467 Garmisch-Partenkirchen, Germany
| | - Alexander Knohl
- Bioclimatology, University of Göttingen, Büsgenweg 2, 37077 Göttingen, Germany
| | - Franziska Koebsch
- Department for Landscape Ecology and Site Evaluation, University of Rostock, Justus von Liebig Weg 6, 18059 Rostock, Germany
| | - Jan Konopka
- Climatology and Environmental Meteorology, Institute of Geoecology, Technische Universität Braunschweig, Langer Kamp 19c, 38106 Braunschweig, Germany
| | - Mika Korkiakoski
- Climate System Research Unit, Finnish Meteorological Institute, PO Box 503, 00101 Helsinki, Finland
| | - Natalia Kowalska
- Department of Matter and Energy Fluxes, Global Change Research Institute of the Czech Academy of Sciences, Bělidla 986/4a, 60300 Brno, Czech Republic
| | - Pascal Kremer
- Institute of Soil Science and Land Evaluation, University of Hohenheim, Emil-Wolff-Straße 27, 70599 Stuttgart, Germany
| | - Bart Kruijt
- Department of Environmental Sciences, Wageningen University and Research, PO Box 47, 6700 AA Wageningen, The Netherlands
| | - Sebastien Lafont
- ISPA, Bordeaux Sciences Agro, INRAE, 33140, Villenave d'Ornon, France
| | - Joël Léonard
- BioEcoAgro Joint Research Unit, INRAE, Université de Liège, Université de Lille, Université de Picardie Jules Verne, 02000 Barenton-Bugny, France
| | - Anne De Ligne
- Terra Teaching and Research Centre, University of Liege - Gembloux Agro-Bio Tech, Avenue de la Faculté, 8, 5030 Gembloux, Belgium
| | - Bernard Longdoz
- Terra Teaching and Research Centre, University of Liege - Gembloux Agro-Bio Tech, Avenue de la Faculté, 8, 5030 Gembloux, Belgium
| | - Denis Loustau
- ISPA, Bordeaux Sciences Agro, INRAE, 33140, Villenave d'Ornon, France
| | - Vincenzo Magliulo
- CNR - Institute for Agricultural and Forest Systems, Via Patacca, 85, 80040 Ercolano (Napoli), Italy
| | - Ivan Mammarella
- Institute for Atmospheric and Earth System Research/Physics, Faculty of Science, University of Helsinki, Gustaf Hällströmin katu 2B, 00014 Helsinki, Finland
| | - Giovanni Manca
- European Commission, Joint Research Centre (JRC), Ispra, Italy
| | - Matthias Mauder
- Institute of Meteorology and Climate Research - Atmospheric Environmental Research, Karlsruhe Institute of Technology, Campus Alpin, Kreuzeckbahnstraße 19, 82467 Garmisch-Partenkirchen, Germany
| | - Mirco Migliavacca
- Department of Biogeochemical Integration, Max Planck Institute for Biogeochemistry, Hans-Knöll-Straße 10, 07745 Jena, Germany
| | - Meelis Mölder
- Department of Physical Geography and Ecosystem Science, Lund University, Sölvegatan 12, 22362 Lund, Sweden
| | - Johan Neirynck
- Research Institute for Nature and Forest, INBO, Havenlaan 88 Box 73, 1000 Brussels, Belgium
| | - Patrizia Ney
- Institute of Bio- and Geosciences: Agrosphere (IBG3), Forschungszentrum Jülich, Wilhelm-Johnen-Straße, 52428 Jülich, Germany
| | - Mats Nilsson
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Skogsmarksgränd 17, 90183 Umeå, Sweden
| | - Eugénie Paul-Limoges
- Department of Geography, University of Zurich, Winterthurerstraße 190, 8057 Zurich, Switzerland
| | - Matthias Peichl
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Skogsmarksgränd 17, 90183 Umeå, Sweden
| | - Andrea Pitacco
- Department of Agronomy, Food, Natural resources, Animals and Environment, University of Padova, Viale dell'Università 16, 35020 Legnaro, Italy
| | - Arne Poyda
- Institute of Soil Science and Land Evaluation, University of Hohenheim, Emil-Wolff-Straße 27, 70599 Stuttgart, Germany.,Institute of Crop Science and Plant Breeding, Grass and Forage Science/Organic Agriculture, Christian-Albrechts-University Kiel, Hermann-Rodewald-Straße 9, 24118 Kiel, Germany
| | - Corinna Rebmann
- Helmholtz Centre for Environmental Research GmbH - UFZ, Department Computational Hydrosystems, Permoserstraße 15, 04318 Leipzig, Germany
| | - Marilyn Roland
- University of Antwerp, Plants and Ecosystems, Universiteitsplein 1, 2610 Wilrijk, Belgium
| | - Torsten Sachs
- Remote Sensing and Geoinformatics, German Research Centre for Geosciences (GFZ), Telegrafenberg, 14473 Potsdam, Germany
| | - Marius Schmidt
- Institute of Bio- and Geosciences: Agrosphere (IBG3), Forschungszentrum Jülich, Wilhelm-Johnen-Straße, 52428 Jülich, Germany
| | - Frederik Schrader
- Institute of Climate-Smart Agriculture, Johann Heinrich von Thünen Institute, Bundesallee 65, 38116 Braunschweig, Germany
| | - Lukas Siebicke
- Bioclimatology, University of Göttingen, Büsgenweg 2, 37077 Göttingen, Germany
| | - Ladislav Šigut
- Department of Matter and Energy Fluxes, Global Change Research Institute of the Czech Academy of Sciences, Bělidla 986/4a, 60300 Brno, Czech Republic
| | - Eeva-Stiina Tuittila
- School of Forest Sciences, University of Eastern Finland, Yliopistokatu 7, 80101 Joensuu, Finland
| | - Andrej Varlagin
- Laboratory of Biocentology, A.N. Severtsov Institute of Ecology and Evolution, Russian Academy of Sciences, Leninsky pr.33, Moscow 119071, Russia
| | - Nadia Vendrame
- Department of Agronomy, Food, Natural resources, Animals and Environment, University of Padova, Viale dell'Università 16, 35020 Legnaro, Italy
| | - Caroline Vincke
- Environmental Sciences, Earth and Life Institute, Université catholique de Louvain, 1348 Louvain-la-Neuve, Belgium
| | - Ingo Völksch
- Institute of Meteorology and Climate Research - Atmospheric Environmental Research, Karlsruhe Institute of Technology, Campus Alpin, Kreuzeckbahnstraße 19, 82467 Garmisch-Partenkirchen, Germany
| | - Stephan Weber
- Climatology and Environmental Meteorology, Institute of Geoecology, Technische Universität Braunschweig, Langer Kamp 19c, 38106 Braunschweig, Germany
| | - Christian Wille
- Remote Sensing and Geoinformatics, German Research Centre for Geosciences (GFZ), Telegrafenberg, 14473 Potsdam, Germany
| | - Hans-Dieter Wizemann
- Institute of Physics and Meteorology, University of Hohenheim, 70593 Stuttgart, Germany
| | - Matthias Zeeman
- Institute of Meteorology and Climate Research - Atmospheric Environmental Research, Karlsruhe Institute of Technology, Campus Alpin, Kreuzeckbahnstraße 19, 82467 Garmisch-Partenkirchen, Germany
| | - Harry Vereecken
- Institute of Bio- and Geosciences: Agrosphere (IBG3), Forschungszentrum Jülich, Wilhelm-Johnen-Straße, 52428 Jülich, Germany
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12
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Ye W, Cai J, Huang Y, Zhi C, Zhang X. Experimental Assessment of Thermal Performance and Bridging Effects of Low-Cost Sandwich Panels under a High-Temperature Impinging Jet. Materials (Basel) 2020; 13:E3620. [PMID: 32824354 DOI: 10.3390/ma13163620] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 08/11/2020] [Accepted: 08/14/2020] [Indexed: 11/17/2022]
Abstract
Sandwich panels are commonly used across industries for their ability to bear structural and thermal loads. In this paper, a panel chamber matching apparatus was designed to investigate the thermal performance of eight steel-based panels by exposing them to an impinging jet at approximately 550 °C for 30 min. Three types of low-cost materials (polycrystalline filaments, silica aerogel, and aluminum silicate) were used as the insulation core. The temperature of the panel surfaces was measured, as well as the metallic fasteners, including bolts, nails, battens, seams, and angle iron, to examine their thermal bridge effects. Major conclusions include the following: first, the maximum temperature on the impinged surface was consistent among all 20 cases, whereas that of the surface under free convection varied, ranging from 41 to 120 °C, depending on the core and thermal bridges. Second, most of the highest temperatures on opposite surfaces were caused by a section of bare angle iron, and this bridging effect could be significantly reduced by up to 50 °C using a few layers of cloth, although the improvement could be temporary. Bolts and nails were less effective as thermal bridges, while the battens could be more effective. Third, the estimated heat flux of all specimens ranged from 167 to 331 W·m−2.
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13
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Domínguez-Pumar M, Rodríguez-Manfredi JA, Jiménez V, Bermejo S, Pons-Nin J. A Miniaturized 3D Heat Flux Sensor to Characterize Heat Transfer in Regolith of Planets and Small Bodies. Sensors (Basel) 2020; 20:E4135. [PMID: 32722361 PMCID: PMC7435945 DOI: 10.3390/s20154135] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/07/2020] [Revised: 07/16/2020] [Accepted: 07/23/2020] [Indexed: 11/16/2022]
Abstract
The objective of this work is to present the first analytical and experimental results obtained with a 3D heat flux sensor for planetary regolith. The proposed structure, a sphere divided in four sectors, is sensible to heat flow magnitude and angle. Each sector includes a platinum resistor that is used both to sense its temperature and provide heating power. By operating the sectors at constant temperature, the sensor gives a response that is proportional to the heat flux vector in the regolith. The response of the sensor is therefore independent of the thermal conductivity of the regolith. A complete analytical solution of the response of the sensor is presented. The sensor may be used to provide information on the instantaneous local thermal environment surrounding a lander in planetary exploration or in small bodies like asteroids. To the best knowledge of the authors, this is the first sensor capable of measuring local 3D heat flux.
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Affiliation(s)
- Manuel Domínguez-Pumar
- Micro and Nano Technologies Group, Electronic Engineering Department, Universitat Politècnica de Catalunya—BarcelonaTech, 08034 Barcelona, Spain; (V.J.); (S.B.); (J.P.-N.)
| | | | - Vicente Jiménez
- Micro and Nano Technologies Group, Electronic Engineering Department, Universitat Politècnica de Catalunya—BarcelonaTech, 08034 Barcelona, Spain; (V.J.); (S.B.); (J.P.-N.)
| | - Sandra Bermejo
- Micro and Nano Technologies Group, Electronic Engineering Department, Universitat Politècnica de Catalunya—BarcelonaTech, 08034 Barcelona, Spain; (V.J.); (S.B.); (J.P.-N.)
| | - Joan Pons-Nin
- Micro and Nano Technologies Group, Electronic Engineering Department, Universitat Politècnica de Catalunya—BarcelonaTech, 08034 Barcelona, Spain; (V.J.); (S.B.); (J.P.-N.)
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14
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Talih S, Salman R, Karam E, El-Hourani M, El-Hage R, Karaoghlanian N, El-Hellani A, Saliba N, Shihadeh A. Hot Wires and Film Boiling: Another Look at Carbonyl Formation in Electronic Cigarettes. Chem Res Toxicol 2020; 33:10.1021/acs.chemrestox.0c00196. [PMID: 32635721 PMCID: PMC9355290 DOI: 10.1021/acs.chemrestox.0c00196] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Electronic cigarettes (ECIGs) are a class of tobacco products that emit a nicotine-containing aerosol by heating and vaporizing a liquid. Apart from initiating nicotine addiction in nonsmokers, a persistent concern about these products is that their emissions often include high levels of carbonyl species, toxicants thought to cause most noncancer pulmonary diseases in smokers. This study examined whether the phenomenon of film boiling can account for observations of high carbonyl emissions under certain operating conditions and, if so, whether film boiling theory can be invoked to predict conditions where high carbonyl emissions are likely. We measured the critical heat flux for several common heating materials and liquids and carbonyl emissions for several ECIG types while varying the power. We found that emissions rise drastically whenever the power exceeds the value corresponding to the critical heat flux. While limiting the heat flux to below this threshold can greatly reduce carbonyl exposure, ECIG manufacturer operating instructions often exceed it. Product regulations that limit heat flux may reduce the public health burden of electronic cigarette use.
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Affiliation(s)
- Soha Talih
- Mechanical Engineering Department, Faculty of Engineering and Architecture, American University of Beirut, Bliss Street, P.O. Box 11-0236, Beirut, Lebanon
- Center for the Study of Tobacco Products, Psychology Department, Virginia Commonwealth University, USA
| | - Rola Salman
- Mechanical Engineering Department, Faculty of Engineering and Architecture, American University of Beirut, Bliss Street, P.O. Box 11-0236, Beirut, Lebanon
- Center for the Study of Tobacco Products, Psychology Department, Virginia Commonwealth University, USA
| | - Ebrahim Karam
- Mechanical Engineering Department, Faculty of Engineering and Architecture, American University of Beirut, Bliss Street, P.O. Box 11-0236, Beirut, Lebanon
- Center for the Study of Tobacco Products, Psychology Department, Virginia Commonwealth University, USA
| | - Mario El-Hourani
- Mechanical Engineering Department, Faculty of Engineering and Architecture, American University of Beirut, Bliss Street, P.O. Box 11-0236, Beirut, Lebanon
- Center for the Study of Tobacco Products, Psychology Department, Virginia Commonwealth University, USA
| | - Rachel El-Hage
- Chemistry Department, Faculty of Arts and Sciences, American University of Beirut, Bliss Street, P.O. Box 11-0236, Beirut, Lebanon
- Center for the Study of Tobacco Products, Psychology Department, Virginia Commonwealth University, USA
| | - Nareg Karaoghlanian
- Mechanical Engineering Department, Faculty of Engineering and Architecture, American University of Beirut, Bliss Street, P.O. Box 11-0236, Beirut, Lebanon
- Center for the Study of Tobacco Products, Psychology Department, Virginia Commonwealth University, USA
| | - Ahmad El-Hellani
- Chemistry Department, Faculty of Arts and Sciences, American University of Beirut, Bliss Street, P.O. Box 11-0236, Beirut, Lebanon
- Center for the Study of Tobacco Products, Psychology Department, Virginia Commonwealth University, USA
| | - Najat Saliba
- Chemistry Department, Faculty of Arts and Sciences, American University of Beirut, Bliss Street, P.O. Box 11-0236, Beirut, Lebanon
- Center for the Study of Tobacco Products, Psychology Department, Virginia Commonwealth University, USA
| | - Alan Shihadeh
- Mechanical Engineering Department, Faculty of Engineering and Architecture, American University of Beirut, Bliss Street, P.O. Box 11-0236, Beirut, Lebanon
- Center for the Study of Tobacco Products, Psychology Department, Virginia Commonwealth University, USA
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15
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Kishore RA, Nozariasbmarz A, Poudel B, Priya S. High-Performance Thermoelectric Generators for Field Deployments. ACS Appl Mater Interfaces 2020; 12:10389-10401. [PMID: 32040298 DOI: 10.1021/acsami.9b21299] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Thermoelectric power generation is a reliable energy harvesting technique for directly converting heat into electricity. Recent studies have reported the thermal-to-electrical energy conversion efficiency of thermoelectric generators (TEGs) up to 11% under laboratory settings. However, the practical efficiency of TEGs deployed under real environments is still not more than a few percent. In this study, we provide fundamental insight on the operation of TEGs in realistic environments by illustrating the combinatory effect of thermoelectric material properties, device boundary conditions, and environmental thermal resistivity on TEG performance in conjunction with the module parameters. Using numerical and experimental studies, we demonstrate the existence of a critical heat transfer coefficient that dramatically affects the design and performance of TEGs. Results provide a set of concrete design criteria for developing efficient TEGs that meet the metrics for field deployments. High-performance TEGs demonstrated in this study generated up to 28% higher power and 162% higher power per unit mass of thermoelectric materials as compared to the commercial module deployed for low-grade waste heat recovery. This advancement in understanding the TEG operation will have a transformative impact on the development of scalable thermal energy harvesters and in realizing their practical targets for efficiency, power density, and total output power.
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Affiliation(s)
- Ravi Anant Kishore
- Center for Energy Harvesting Materials and Systems, Virginia Tech, Blacksburg, Virginia 24061, United States
- National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, Colorado 80401, United States
| | - Amin Nozariasbmarz
- Department of Materials Science and Engineering, Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Bed Poudel
- Department of Materials Science and Engineering, Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Shashank Priya
- Center for Energy Harvesting Materials and Systems, Virginia Tech, Blacksburg, Virginia 24061, United States
- Department of Materials Science and Engineering, Pennsylvania State University, University Park, Pennsylvania 16802, United States
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16
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Kim JH, Seo Y, Quinn T, Yorio P, Roberge R. Intersegmental differences in facial warmth sensitivity during rest, passive heat and exercise. Int J Hyperthermia 2020; 36:654-659. [PMID: 31311353 DOI: 10.1080/02656736.2019.1627430] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
Abstract
Background: Increased facial warmth sensations could lead to thermal discomfort, and different facial regions may demonstrate concurrent temperature differences. The study aim was examining facial warmth sensitivity differences by facial region under differing environmental conditions. Methods: Twelve men had heat flux measurements of six facial regions during 30 min each of rest in thermoneutral conditions (25 °C, 30% relative humidity (RH)), rest in warm conditions (40 °C, 30% RH), and cycling at 400 W of metabolic heat production (40 °C, 30% RH). Results: The forehead demonstrated highest temperatures at termination of all study conditions; lowest temperatures were noted for the nose under thermoneutral conditions and chin during warmth and exercise conditions. Five of six facial regions demonstrated significant differences in warmth sensitivity, decreasing to two of six regions during warm conditions and one of six regions during exercise, with the upper lip most sensitive in all conditions. Body thermal comfort (TC) perceptions, regressed individually on mean facial temperature (Tface) vs. core temperature (Tco), indicated that Tface was significantly more related than Tco to perceived TC (p = .001). Perceived TC, regressed individually on perceived overall body thermal sensation (TS) vs. facial TS, demonstrated that Tface was significantly more related to perceived TC (p = .004). Conclusion: There were regional differences in facial warmth sensitivity together with different facial temperatures moving toward equilibration when the body is subjected to heat-producing activities. Perceptions of TC were more strongly related to Tface than to Tco or overall body TS.
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Affiliation(s)
- Jung-Hyun Kim
- a Department of Sports Medicine , Kyung Hee University , Yongin-si , South Korea.,b Centers for Disease Control and Prevention , National Institute for Occupational Safety and Health, National Personal Protective Technology Laboratory , Pittsburgh , PA , USA
| | - Yongsuk Seo
- b Centers for Disease Control and Prevention , National Institute for Occupational Safety and Health, National Personal Protective Technology Laboratory , Pittsburgh , PA , USA
| | - Tyler Quinn
- b Centers for Disease Control and Prevention , National Institute for Occupational Safety and Health, National Personal Protective Technology Laboratory , Pittsburgh , PA , USA
| | - Patrick Yorio
- b Centers for Disease Control and Prevention , National Institute for Occupational Safety and Health, National Personal Protective Technology Laboratory , Pittsburgh , PA , USA
| | - Raymond Roberge
- b Centers for Disease Control and Prevention , National Institute for Occupational Safety and Health, National Personal Protective Technology Laboratory , Pittsburgh , PA , USA
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17
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Carballo-Leyenda B, Villa JG, López-Satué J, Rodríguez-Marroyo JA. Characterizing Wildland Firefighters' Thermal Environment During Live-Fire Suppression. Front Physiol 2019; 10:949. [PMID: 31427982 PMCID: PMC6688527 DOI: 10.3389/fphys.2019.00949] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Accepted: 07/09/2019] [Indexed: 11/23/2022] Open
Abstract
Wildland firefighters work under adverse environments (e.g., heat and fire exposure), which contribute to increasing the heat strain. Despite this there is a paucity of knowledge about the thermal environment in real wildfire suppression scenarios. Therefore, the main purpose of this study was to characterize the environmental thermal exposure and the risk of heat burn injuries during real wildfire suppression (n = 23). To characterize the wildland firefighter’s (n = 5) local thermal exposure, measurements of air temperature and heat flux were performed. Heat flux measurements were made using four thin-planar heat flux sensors. Two were affixed on the outer surface of the garment on the left chest and thigh. Two other sensors were placed on the inner surface of the fabric in parallel to those placed externally. Four thermal classes were defined based on the heat flux across the inner sensors (≤1000, ≤5000, ≤7000, and >7000 W⋅m–2). The risk of pain and first-degree burns were calculated using the dose of thermal radiation method. The inner sensors mean and maximum heat flux and environment temperature were 286.7 ± 255.0 and 2370.4 ± 3004.5 W⋅m–2 and 32.6 ± 8.9 and 78.0 ± 8.9°C, respectively. Approximately 81, 15, and 3.5% of the exposure time the heat flux was ≤1000, >1000–5000, and >5000 W⋅m–2, respectively. The highest average and maximum thermal dose values were ∼94 and ∼110 (kW⋅m–2)4/3⋅s. In conclusion, the thermal exposure obtained may be considered light. However, high thermal exposure values may be obtained in punctual moments, which can elicit first-degree burns.
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Affiliation(s)
| | - José G Villa
- VALFIS Research Group, Institute of Biomedicine, University of León, León, Spain
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18
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Domínguez-Pumar M, Pérez E, Ramón M, Jiménez V, Bermejo S, Pons-Nin J. Acceleration of the Measurement Time of Thermopiles Using Sigma-Delta Control. Sensors (Basel) 2019; 19:s19143159. [PMID: 31323801 PMCID: PMC6679300 DOI: 10.3390/s19143159] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/25/2019] [Revised: 07/10/2019] [Accepted: 07/16/2019] [Indexed: 11/21/2022]
Abstract
This work presents a double sliding mode control designed for accelerating the measurement of heat fluxes using thermopiles. The slow transient response generated in the thermopile, when it is placed in contact with the surface to be measured, is due to the changes in the temperature distributions that this operation triggers. It is shown that under some conditions the proposed controls keep the temperature distribution of the whole system constant and that changes in the heat flux at the thermopile are almost instantaneously compensated by the controls. One-dimensional simulations and experimental results using a commercial thermopile, showing the goodness of the proposed approach, are presented. A first rigorous analysis of the control using the Sliding Mode Control and Diffusive Representation theories is also made.
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Affiliation(s)
- Manuel Domínguez-Pumar
- Micro and Nano Technologies Group, Electronic Engineering Department, Universitat Politècnica de Catalunya-BarcelonaTech, 08034 Barcelona, Spain.
| | - Eduard Pérez
- Micro and Nano Technologies Group, Electronic Engineering Department, Universitat Politècnica de Catalunya-BarcelonaTech, 08034 Barcelona, Spain
| | - Marina Ramón
- Micro and Nano Technologies Group, Electronic Engineering Department, Universitat Politècnica de Catalunya-BarcelonaTech, 08034 Barcelona, Spain
| | - Vicente Jiménez
- Micro and Nano Technologies Group, Electronic Engineering Department, Universitat Politècnica de Catalunya-BarcelonaTech, 08034 Barcelona, Spain
| | - Sandra Bermejo
- Micro and Nano Technologies Group, Electronic Engineering Department, Universitat Politècnica de Catalunya-BarcelonaTech, 08034 Barcelona, Spain
| | - Joan Pons-Nin
- Micro and Nano Technologies Group, Electronic Engineering Department, Universitat Politècnica de Catalunya-BarcelonaTech, 08034 Barcelona, Spain.
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19
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Eggenberger P, MacRae BA, Kemp S, Bürgisser M, Rossi RM, Annaheim S. Prediction of Core Body Temperature Based on Skin Temperature, Heat Flux, and Heart Rate Under Different Exercise and Clothing Conditions in the Heat in Young Adult Males. Front Physiol 2018; 9:1780. [PMID: 30618795 PMCID: PMC6295644 DOI: 10.3389/fphys.2018.01780] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Accepted: 11/26/2018] [Indexed: 12/12/2022] Open
Abstract
Non-invasive, multi-parameter methods to estimate core body temperature offer several advantages for monitoring thermal strain, although further work is required to identify the most relevant predictor measures. This study aimed to compare the validity of an existing and two novel multi-parameter rectal temperature prediction models. Thirteen healthy male participants (age 30.9 ± 5.4 years) performed two experimental sessions. The experimental procedure comprised 15 min baseline seated rest (23.2 ± 0.3°C, 24.5 ± 1.6% relative humidity), followed by 15 min seated rest and cycling in a climatic chamber (35.4 ± 0.2°C, 56.5 ± 3.9% relative humidity; to +1.5°C or maximally 38.5°C rectal temperature, duration 20-60 min), with a final 30 min seated rest outside the chamber. In session 1, participants exercised at 75% of their heart rate maximum (HR max) and wore light athletic clothing (t-shirt and shorts), while in session 2, participants exercised at 50% HR max, wearing protective firefighter clothing (jacket and trousers). The first new prediction model, comprising the input of 18 non-invasive measures, i.e., insulated and non-insulated skin temperature, heat flux, and heart rate ("Max-Input Model", standard error of the estimate [SEE] = 0.28°C, R2 = 0.70), did not exceed the predictive power of a previously reported model which included six measures and no insulated skin temperatures (SEE = 0.28°C, R2 = 0.71). Moreover, a second new prediction model that contained only the two most relevant parameters (heart rate and insulated skin temperature at the scapula) performed similarly ("Min-Input Model", SEE = 0.29, R2 = 0.68). In conclusion, the "Min-Input Model" provided comparable validity and superior practicality (only two measurement parameters) for estimating rectal temperature versus two other models requiring six or more input measures.
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Affiliation(s)
- Patrick Eggenberger
- Empa, Swiss Federal Laboratories for Materials Science and Technology, Laboratory for Biomimetic Membranes and Textiles, St. Gallen, Switzerland
| | - Braid A. MacRae
- Empa, Swiss Federal Laboratories for Materials Science and Technology, Laboratory for Biomimetic Membranes and Textiles, St. Gallen, Switzerland
- Institute of Human Movement Sciences and Sport, Department of Health Sciences and Technology, ETH Zurich, Zurich, Switzerland
| | - Shelley Kemp
- Empa, Swiss Federal Laboratories for Materials Science and Technology, Laboratory for Biomimetic Membranes and Textiles, St. Gallen, Switzerland
| | - Michael Bürgisser
- Empa, Swiss Federal Laboratories for Materials Science and Technology, Laboratory for Biomimetic Membranes and Textiles, St. Gallen, Switzerland
- Institute of Human Movement Sciences and Sport, Department of Health Sciences and Technology, ETH Zurich, Zurich, Switzerland
| | - René M. Rossi
- Empa, Swiss Federal Laboratories for Materials Science and Technology, Laboratory for Biomimetic Membranes and Textiles, St. Gallen, Switzerland
| | - Simon Annaheim
- Empa, Swiss Federal Laboratories for Materials Science and Technology, Laboratory for Biomimetic Membranes and Textiles, St. Gallen, Switzerland
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Pradeep Kumar J. Effect of Temperature Distribution in Ultrasonically Welded Joints of Copper Wire and Sheet Used for Electrical Contacts. Materials (Basel) 2018; 11:ma11061010. [PMID: 29904006 PMCID: PMC6025159 DOI: 10.3390/ma11061010] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Revised: 06/09/2018] [Accepted: 06/12/2018] [Indexed: 11/16/2022]
Abstract
The temperature distribution occurring at the interface while joining a simple electrical contact comprising of a copper wire and a copper sheet using ultrasonic metal welding was analyzed using finite element method. Heat flux due to plastic deformation and friction was calculated and provided as input load for simulation of temperature distribution. The results of temperature obtained from simulation are found to be in good agreement with the results of temperature from experiments measured using thermocouple. Special focus was given to how the heat generated at the wire⁻sheet interface affect the strength of the joint in tension. With the knowledge of heat generated at the interface while welding, it is possible to control the strength of the joint and produce defect free joints. Based on the results from finite element analysis and experiments, it is observed that the influence of heat developed due to friction and plastic deformation of metallic specimens has a significant effect on the progress of welding and strength of the joint.
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Affiliation(s)
- Jeyaraj Pradeep Kumar
- Department of Production Engineering, PSG College of Technology, Coimbatore 641 004, Tamil Nadu, India.
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Mendt S, Maggioni MA, Nordine M, Steinach M, Opatz O, Belavý D, Felsenberg D, Koch J, Shang P, Gunga HC, Stahn A. Circadian rhythms in bed rest: Monitoring core body temperature via heat-flux approach is superior to skin surface temperature. Chronobiol Int 2016; 34:666-676. [PMID: 27726448 DOI: 10.1080/07420528.2016.1224241] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Continuous recordings of core body temperature (CBT) are a well-established approach in describing circadian rhythms. Given the discomfort of invasive CBT measurement techniques, the use of skin temperature recordings has been proposed as a surrogate. More recently, we proposed a heat-flux approach (the so-called Double Sensor) for monitoring CBT. Studies investigating the reliability of the heat-flux approach over a 24-hour period, as well as comparisons with skin temperature recordings, are however lacking. The first aim of the study was therefore to compare rectal, skin, and heat-flux temperature recordings for monitoring circadian rhythm. In addition, to assess the optimal placement of sensor probes, we also investigated the effect of different anatomical measurement sites, i.e. sensor probes positioned at the forehead vs. the sternum. Data were collected as part of the Berlin BedRest study (BBR2-2) under controlled, standardized, and thermoneutral conditions. 24-hours temperature data of seven healthy males were collected after 50 days of -6° head-down tilt bed-rest. Mean Pearson correlation coefficients indicated a high association between rectal and forehead temperature recordings (r > 0.80 for skin and Double Sensor). In contrast, only a poor to moderate relationship was observed for sensors positioned at the sternum (r = -0.02 and r = 0.52 for skin and Double Sensor, respectively). Cross-correlation analyses further confirmed the feasibility of the forehead as a preferred monitoring site. The phase difference between forehead Double Sensor and rectal recordings was not statistically different from zero (p = 0.313), and was significantly smaller than the phase difference between forehead skin and rectal temperatures (p = 0.016). These findings were substantiated by cosinor analyses, revealing significant differences for mesor, amplitude, and acrophase between rectal and forehead skin temperature recordings, but not between forehead Double Sensor and rectal temperature measurements. Finally, Bland-Altman analysis indicated narrower limits of agreement for rhythm parameters between rectal and Double Sensor measurements compared to between rectal and skin recordings, irrespective of the measurement site (i.e. forehead, sternum). Based on these data we conclude that (1) Double Sensor recordings are significantly superior to skin temperature measurements for non-invasively assessing the circadian rhythm of rectal temperature, and (2) temperature rhythms from the sternum are less reliable than from the forehead. We suggest that forehead Double Sensor recordings may provide a surrogate for rectal temperature in circadian rhythm research, where constant routine protocols are applied. Future studies will be needed to assess the sensor's ecological validity outside the laboratory under changing environmental and physiological conditions.
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Affiliation(s)
- Stefan Mendt
- a Institute of Physiology, Center for Space Medicine and Extreme Environments , Charité Universitätsmedizin , Berlin , Germany
| | - Martina Anna Maggioni
- a Institute of Physiology, Center for Space Medicine and Extreme Environments , Charité Universitätsmedizin , Berlin , Germany.,b Department of Biomedical Sciences for Health , Universitá degli Studi di Milano , Milan , Italy
| | - Michael Nordine
- a Institute of Physiology, Center for Space Medicine and Extreme Environments , Charité Universitätsmedizin , Berlin , Germany
| | - Mathias Steinach
- a Institute of Physiology, Center for Space Medicine and Extreme Environments , Charité Universitätsmedizin , Berlin , Germany
| | - Oliver Opatz
- a Institute of Physiology, Center for Space Medicine and Extreme Environments , Charité Universitätsmedizin , Berlin , Germany
| | - Daniel Belavý
- c Centre for Muscle and Bone Research , Charité Universitätsmedizin , Berlin , Germany.,d Institute for Physical Activity and Nutrition, Deakin University , Burwood , Australia
| | - Dieter Felsenberg
- c Centre for Muscle and Bone Research , Charité Universitätsmedizin , Berlin , Germany
| | - Jochim Koch
- e Drägerwerk AG & Co. KGaA, Lübeck , Germany
| | - Peng Shang
- f Key Laboratory for Space Bioscience & Biotechnology , Northwestern Polytechnical University , Xi'an , China
| | - Hanns-Christian Gunga
- a Institute of Physiology, Center for Space Medicine and Extreme Environments , Charité Universitätsmedizin , Berlin , Germany
| | - Alexander Stahn
- a Institute of Physiology, Center for Space Medicine and Extreme Environments , Charité Universitätsmedizin , Berlin , Germany.,g Division of Sleep and Chronobiology , Unit of Experimental Psychiatry, Perelman School of Medicine, University of Pennsylvania , Philadelphia , PA , USA
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Ziouche K, Lejeune P, Bougrioua Z, Leclercq D. Dispersion of Heat Flux Sensors Manufactured in Silicon Technology. Sensors (Basel) 2016; 16:s16060853. [PMID: 27294929 PMCID: PMC4934279 DOI: 10.3390/s16060853] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Revised: 05/31/2016] [Accepted: 06/03/2016] [Indexed: 11/16/2022]
Abstract
In this paper, we focus on the dispersion performances related to the manufacturing process of heat flux sensors realized in CMOS (Complementary metal oxide semi-conductor) compatible 3-in technology. In particular, we have studied the performance dispersion of our sensors and linked these to the physical characteristics of dispersion of the materials used. This information is mandatory to ensure low-cost manufacturing and especially to reduce production rejects during the fabrication process. The results obtained show that the measured sensitivity of the sensors is in the range 3.15 to 6.56 μV/(W/m²), associated with measured resistances ranging from 485 to 675 kΩ. The dispersions correspond to a Gaussian-type distribution with more than 90% determined around average sensitivity S e ¯ = 4.5 µV/(W/m²) and electrical resistance R ¯ = 573.5 kΩ within the interval between the average and, more or less, twice the relative standard deviation.
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Affiliation(s)
- Katir Ziouche
- Institute of Electronics, Microelectronics and Nanotechnology, University Lille 1 and CNRS; Villeneuve d'Ascq, 59652, France.
| | - Pascale Lejeune
- Institute of Electronics, Microelectronics and Nanotechnology, University Lille 1 and CNRS; Villeneuve d'Ascq, 59652, France.
| | - Zahia Bougrioua
- Institute of Electronics, Microelectronics and Nanotechnology, University Lille 1 and CNRS; Villeneuve d'Ascq, 59652, France.
| | - Didier Leclercq
- Institute of Electronics, Microelectronics and Nanotechnology, University Lille 1 and CNRS; Villeneuve d'Ascq, 59652, France.
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Zhang T, Zhou X, Yang L. Experimental Study of Fire Hazards of Thermal-Insulation Material in Diesel Locomotive: Aluminum-Polyurethane. Materials (Basel) 2016; 9:ma9030168. [PMID: 28773295 PMCID: PMC5456725 DOI: 10.3390/ma9030168] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Revised: 02/24/2016] [Accepted: 02/26/2016] [Indexed: 06/07/2023]
Abstract
This work investigated experimentally and theoretically the fire hazards of thermal-insulation materials used in diesel locomotives under different radiation heat fluxes. Based on the experimental results, the critical heat flux for ignition was determined to be 6.15 kW/m² and 16.39 kW/m² for pure polyurethane and aluminum-polyurethane respectively. A theoretical model was established for both to predict the fire behaviors under different circumstances. The fire behavior of the materials was evaluated based on the flashover and the total heat release rate (HRR). The fire hazards levels were classified based on different experimental results. It was found that the fire resistance performance of aluminum-polyurethane is much better than that of pure-polyurethane under various external heat fluxes. The concentration of toxic pyrolysis volatiles generated from aluminum-polyurethane materials is much higher than that of pure polyurethane materials, especially when the heat flux is below 50 kW/m². The hazard index HI during peak width time was proposed based on the comprehensive impact of time and concentrations. The predicted HI in this model coincides with the existed N-gas and FED models which are generally used to evaluate the fire gas hazard in previous researches. The integrated model named HNF was proposed as well to estimate the fire hazards of materials by interpolation and weighted average calculation.
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Affiliation(s)
- Taolin Zhang
- State Key Laboratory of Fire Science, University of Science and Technology of China, 96 Jinzhai Road, Hefei 230026, China.
| | - Xiaodong Zhou
- State Key Laboratory of Fire Science, University of Science and Technology of China, 96 Jinzhai Road, Hefei 230026, China.
| | - Lizhong Yang
- State Key Laboratory of Fire Science, University of Science and Technology of China, 96 Jinzhai Road, Hefei 230026, China.
- Collaborative Innovation Center for Urban Public Safety, 96 Jinzhai Road, Hefei 230026, China.
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Zhang Y, Chad Webb R, Luo H, Xue Y, Kurniawan J, Cho NH, Krishnan S, Li Y, Huang Y, Rogers JA. Theoretical and Experimental Studies of Epidermal Heat Flux Sensors for Measurements of Core Body Temperature. Adv Healthc Mater 2016; 5:119-27. [PMID: 25953120 DOI: 10.1002/adhm.201500110] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Revised: 03/27/2015] [Indexed: 11/06/2022]
Abstract
Long-term, continuous measurement of core body temperature is of high interest, due to the widespread use of this parameter as a key biomedical signal for clinical judgment and patient management. Traditional approaches rely on devices or instruments in rigid and planar forms, not readily amenable to intimate or conformable integration with soft, curvilinear, time-dynamic, surfaces of the skin. Here, materials and mechanics designs for differential temperature sensors are presented which can attach softly and reversibly onto the skin surface, and also sustain high levels of deformation (e.g., bending, twisting, and stretching). A theoretical approach, together with a modeling algorithm, yields core body temperature from multiple differential measurements from temperature sensors separated by different effective distances from the skin. The sensitivity, accuracy, and response time are analyzed by finite element analyses (FEA) to provide guidelines for relationships between sensor design and performance. Four sets of experiments on multiple devices with different dimensions and under different convection conditions illustrate the key features of the technology and the analysis approach. Finally, results indicate that thermally insulating materials with cellular structures offer advantages in reducing the response time and increasing the accuracy, while improving the mechanics and breathability.
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Affiliation(s)
- Yihui Zhang
- Departments of Civil and Environmental Engineeringand Mechanical Engineering; Center for Engineering and Healthand Skin Disease Research Center, Northwestern University; Evanston IL 60208 USA
- Center for Mechanics and Materials; Tsinghua University; Beijing 100084 China
| | - Richard Chad Webb
- Department of Materials Science and Engineering, Frederick Seitz Materials Research Laboratory; University of Illinois at Urbana-Champaign; Urbana IL 61801 USA
| | - Hongying Luo
- Departments of Civil and Environmental Engineeringand Mechanical Engineering; Center for Engineering and Healthand Skin Disease Research Center, Northwestern University; Evanston IL 60208 USA
- School of Aerospace Engineering and Applied Mechanics; Tongji University; Shanghai 200092 China
| | - Yeguang Xue
- Departments of Civil and Environmental Engineeringand Mechanical Engineering; Center for Engineering and Healthand Skin Disease Research Center, Northwestern University; Evanston IL 60208 USA
| | - Jonas Kurniawan
- Department of Materials Science and Engineering, Frederick Seitz Materials Research Laboratory; University of Illinois at Urbana-Champaign; Urbana IL 61801 USA
| | - Nam Heon Cho
- Department of Materials Science and Engineering, Frederick Seitz Materials Research Laboratory; University of Illinois at Urbana-Champaign; Urbana IL 61801 USA
| | - Siddharth Krishnan
- Department of Materials Science and Engineering, Frederick Seitz Materials Research Laboratory; University of Illinois at Urbana-Champaign; Urbana IL 61801 USA
| | - Yuhang Li
- Departments of Civil and Environmental Engineeringand Mechanical Engineering; Center for Engineering and Healthand Skin Disease Research Center, Northwestern University; Evanston IL 60208 USA
- Institute of Solid Mechanics; Beihang University; Beijing 100191 China
| | - Yonggang Huang
- Departments of Civil and Environmental Engineeringand Mechanical Engineering; Center for Engineering and Healthand Skin Disease Research Center, Northwestern University; Evanston IL 60208 USA
| | - John A. Rogers
- Department of Materials Science and Engineering Chemistry, Mechanical Science and Engineering, Electrical and Computer Engineering; Beckman Institute for Advanced Science and Technology and Frederick Seitz Materials Research Laboratory; University of Illinois at Urbana-Champaign; Urbana IL 61801 USA
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Zhang Y, Chad Webb R, Luo H, Xue Y, Kurniawan J, Cho NH, Krishnan S, Li Y, Huang Y, Rogers JA. Flexible Electronics: Theoretical and Experimental Studies of Epidermal Heat Flux Sensors for Measurements of Core Body Temperature (Adv. Healthcare Mater. 1/2016). Adv Healthc Mater 2016; 5:2. [PMID: 26749418 DOI: 10.1002/adhm.201670002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
On page 119, J. A. Rogers and co-workers present theoretical approaches, modeling algorithms, materials, and device designs for the noninvasive measurement of core body temperature by using multiple differential temperature sensors that attach softly and intimately onto the surface of the skin. The image shows the construction of differential temperature sensors using thermally insulating foam as the separation material.
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Affiliation(s)
- Yihui Zhang
- Departments of Civil and Environmental Engineeringand Mechanical Engineering; Center for Engineering and Healthand Skin Disease Research Center, Northwestern University; Evanston IL 60208 USA
- Center for Mechanics and Materials; Tsinghua University; Beijing 100084 China
| | - Richard Chad Webb
- Department of Materials Science and Engineering, Frederick Seitz Materials Research Laboratory; University of Illinois at Urbana-Champaign; Urbana IL 61801 USA
| | - Hongying Luo
- Departments of Civil and Environmental Engineeringand Mechanical Engineering; Center for Engineering and Healthand Skin Disease Research Center, Northwestern University; Evanston IL 60208 USA
- School of Aerospace Engineering and Applied Mechanics; Tongji University; Shanghai 200092 China
| | - Yeguang Xue
- Departments of Civil and Environmental Engineeringand Mechanical Engineering; Center for Engineering and Healthand Skin Disease Research Center, Northwestern University; Evanston IL 60208 USA
| | - Jonas Kurniawan
- Department of Materials Science and Engineering, Frederick Seitz Materials Research Laboratory; University of Illinois at Urbana-Champaign; Urbana IL 61801 USA
| | - Nam Heon Cho
- Department of Materials Science and Engineering, Frederick Seitz Materials Research Laboratory; University of Illinois at Urbana-Champaign; Urbana IL 61801 USA
| | - Siddharth Krishnan
- Department of Materials Science and Engineering, Frederick Seitz Materials Research Laboratory; University of Illinois at Urbana-Champaign; Urbana IL 61801 USA
| | - Yuhang Li
- Departments of Civil and Environmental Engineeringand Mechanical Engineering; Center for Engineering and Healthand Skin Disease Research Center, Northwestern University; Evanston IL 60208 USA
- Institute of Solid Mechanics; Beihang University; Beijing 100191 China
| | - Yonggang Huang
- Departments of Civil and Environmental Engineeringand Mechanical Engineering; Center for Engineering and Healthand Skin Disease Research Center, Northwestern University; Evanston IL 60208 USA
| | - John A. Rogers
- Department of Materials Science and Engineering Chemistry, Mechanical Science and Engineering, Electrical and Computer Engineering; Beckman Institute for Advanced Science and Technology and Frederick Seitz Materials Research Laboratory; University of Illinois at Urbana-Champaign; Urbana IL 61801 USA
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26
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Fisher AT, Mankoff KD, Tulaczyk SM, Tyler SW, Foley N. High geothermal heat flux measured below the West Antarctic Ice Sheet. Sci Adv 2015; 1:e1500093. [PMID: 26601210 PMCID: PMC4646773 DOI: 10.1126/sciadv.1500093] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2015] [Accepted: 05/19/2015] [Indexed: 05/24/2023]
Abstract
The geothermal heat flux is a critical thermal boundary condition that influences the melting, flow, and mass balance of ice sheets, but measurements of this parameter are difficult to make in ice-covered regions. We report the first direct measurement of geothermal heat flux into the base of the West Antarctic Ice Sheet (WAIS), below Subglacial Lake Whillans, determined from the thermal gradient and the thermal conductivity of sediment under the lake. The heat flux at this site is 285 ± 80 mW/m(2), significantly higher than the continental and regional averages estimated for this site using regional geophysical and glaciological models. Independent temperature measurements in the ice indicate an upward heat flux through the WAIS of 105 ± 13 mW/m(2). The difference between these heat flux values could contribute to basal melting and/or be advected from Subglacial Lake Whillans by flowing water. The high geothermal heat flux may help to explain why ice streams and subglacial lakes are so abundant and dynamic in this region.
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Affiliation(s)
- Andrew T. Fisher
- Department of Earth and Planetary Sciences, University of California, Santa Cruz, Santa Cruz, CA 95064, USA
| | - Kenneth D. Mankoff
- Department of Earth and Planetary Sciences, University of California, Santa Cruz, Santa Cruz, CA 95064, USA
- Department of Physical Oceanography, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA
| | - Slawek M. Tulaczyk
- Department of Earth and Planetary Sciences, University of California, Santa Cruz, Santa Cruz, CA 95064, USA
| | - Scott W. Tyler
- Department of Geological Sciences and Engineering, University of Nevada, Reno, NV 89557, USA
| | - Neil Foley
- Department of Earth and Planetary Sciences, University of California, Santa Cruz, Santa Cruz, CA 95064, USA
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Abstract
INTRODUCTION The Personal Calorie Monitor (PCM) is a portable direct calorimeter that estimates energy expenditure (EE) from measured heat flux (i.e., the sum of conductive, convective, radiative, and evaporative heat). PURPOSE The primary aim of this study was to compare EE estimated from measures of heat flux with those measured using indirect calorimetry in a thermoneutral environment (26°C). A secondary aim was to determine whether exposure to ambient temperature below thermoneutral condition (19°C) influences the accuracy of the PCM. METHODS Thirty-four adults (mean ± SD: age, 28 ± 5 yr; body mass index, 22.9 ± 2.6 kg · m(-2)) were studied for 5 h in a whole-room indirect calorimeter (IC) in thermoneutral and cool conditions. Participants wore the PCM on their upper arm and completed two 20-min treadmill walking bouts (0% grade, 3 mph). The remaining time was spent sedentary (e.g., watching television, using a computer). RESULTS In thermoneutral conditions, EE values (mean (95% confidence interval)) measured by IC and PCM were 560.0 (526.5-593.5) and 623.3 (535.5-711.1) kcal, respectively. In cool conditions, EE values measured by IC and PCM were 572.5 (540.9-604.0) and 745.5 (668.1-822.8) kcal, respectively. Under thermoneutral conditions, mean PCM minute-by-minute EE tracked closely with IC, resulting in a small nonsignificant bias (63 kcal (-5.8 to 132.4)). During cool conditions, mean PCM minute-by-minute EE did not track IC, resulting in a large bias (173.0 kcal (93.9-252.1)) (P <; 0.001). CONCLUSIONS This study demonstrated the validity of using measured heat flux to estimate EE. However, accuracy may be impaired in cool conditions possibly because of excess heat loss from the exposed limbs.
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Affiliation(s)
- Kate Lyden
- Division of Endocrinology, Metabolism and Diabetes, University of Colorado Anschutz Medical Campus, Aurora, CO
| | - Tracy Swibas
- Division of Geriatric Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO
| | - Victoria Catenacci
- Division of Endocrinology, Metabolism and Diabetes, University of Colorado Anschutz Medical Campus, Aurora, CO
| | - Ruixin Guo
- School of Public Health, University of Colorado Anschutz Medical Campus, Aurora, CO
| | | | - Edward L. Melanson
- Division of Endocrinology, Metabolism and Diabetes, University of Colorado Anschutz Medical Campus, Aurora, CO
- Division of Geriatric Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO
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Sullivan CD, Garcia GJM, Frank-Ito DO, Kimbell JS, Rhee JS. Perception of better nasal patency correlates with increased mucosal cooling after surgery for nasal obstruction. Otolaryngol Head Neck Surg 2013; 150:139-47. [PMID: 24154749 DOI: 10.1177/0194599813509776] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
OBJECTIVES To (1) quantify mucosal cooling (ie, heat loss) spatially in the nasal passages of nasal airway obstruction (NAO) patients before and after surgery using computational fluid dynamics (CFD) and (2) correlate mucosal cooling with patient-reported symptoms, as measured by the Nasal Obstruction Symptom Evaluation (NOSE) and a visual analog scale (VAS) for sensation of nasal airflow. STUDY DESIGN Prospective. SETTING Academic tertiary medical center. SUBJECTS AND METHODS Computed tomography (CT) scans and NOSE and VAS surveys were obtained from 10 patients before and after surgery to relieve NAO. Three-dimensional models of each patient's nasal anatomy were used to run steady-state CFD simulations of airflow and heat transfer during inspiration. Heat loss across the nasal vestibule and the entire nasal cavity, as well as the surface area of mucosa exposed to heat fluxes >50 W/m(2), were compared pre- and postoperatively. RESULTS After surgery, heat loss increased significantly on the preoperative most obstructed side (P < .0002). A larger surface area of nasal mucosa was exposed to heat fluxes >50 W/m(2) after surgery. The best correlation between patient-reported and CFD measures of nasal patency was obtained for NOSE against surface area in which heat fluxes were >50 W/m(2) (Pearson r = -0.76). CONCLUSION A significant postoperative increase in mucosal cooling correlates well with patients' perception of better nasal patency after NAO surgery. Computational fluid dynamics-derived heat fluxes may prove to be a valuable predictor of success in NAO surgery.
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Affiliation(s)
- Corbin D Sullivan
- Department of Otolaryngology and Communication Sciences, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
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Kawai Y, Ando K, Kawamura H. Distortion of near-surface seawater temperature structure by a moored-buoy hull and its effect on skin temperature and heat flux estimates. Sensors (Basel) 2009; 9:6119-30. [PMID: 22454575 PMCID: PMC3312433 DOI: 10.3390/s90806119] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/26/2009] [Revised: 07/27/2009] [Accepted: 07/29/2009] [Indexed: 11/27/2022]
Abstract
Previous studies have suggested that the accuracy of temperature measurements by surface-moored buoys may be affected by distortions of the near-surface temperature structure by the buoy hull on calm, sunny days. We obtained the first definite observational evidence that the temperature near the hull was not horizontally homogeneous at the same nominal depth. We observed large temperature differences of 1.0 K or more between thermometers at 0.2 m depth. The distortion of the surface temperature field yielded an error in estimates of daytime net surface heat flux up to more than 30 Wm(-2).
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Affiliation(s)
- Yoshimi Kawai
- Japan Agency for Marine-Earth Science and Technology, 2-15 Natsushima-Cho, Yokosuka, 237-0061, Japan; E-Mail: (K.A.)
| | - Kentaro Ando
- Japan Agency for Marine-Earth Science and Technology, 2-15 Natsushima-Cho, Yokosuka, 237-0061, Japan; E-Mail: (K.A.)
| | - Hiroshi Kawamura
- Center for Atmospheric and Oceanic Studies, Graduate School of Science, Tohoku University, Aoba-ku, Sendai 980-8578, Japan; E-Mail: (H.K.)
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Abstract
A new surgical drape that is impervious to moisture presumably reduces evaporative heat loss. We compared cutaneous heat loss and skin temperature in volunteers covered with this drape to two conventional surgical drapes (Large Surgical Drape and Medline Proxima). We calculated cutaneous heat loss and skin-surface temperatures from 15 area-weighted thermal flux transducers in eight volunteers. In random order, each of the drapes was evaluated with dry transducers and moistened transducers (simulating wet skin). After a 20-min uncovered control period, volunteers were covered from the neck down for 40 min. Data were recorded continuously and averaged over 10 min. Results were similar for all three drapes for dry or moist conditions. Under dry conditions, baseline heat loss was 82 +/- 14 W and decreased 30% with a surgical drape (P < 0.001). Under moist conditions, baseline heat loss was 231 +/- 45 W and decreased 29% with a drape covering (P < 0.001). Moist skin increased heat loss 282% (P < 0.001). There were no clinically important differences in skin temperature among the covers with dry or moist skin. Moist skin increased heat loss nearly three-fold, but there were no differences among the drapes. We conclude that loss is comparable with impervious and conventional drapes with either moist or dry skin.
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Affiliation(s)
| | - Daniel I. Sessler
- Associate Vice President For Health Affairs, Vice Dean for Research, Director Outcomes Research™ Institute, Lolita & Samuel Weakley Distinguished University Research Chair, Professor of Anesthesiology and Pharmacology, University of Louisville
| | - Rainer Lenhardt
- Assistant Professor, Department of Anesthesiology and Outcomes Research™ Institute, and Director Neuroscience ICU, University of Louisville
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Murthy AV. A Summary of Heat-Flux Sensor Calibration Data. J Res Natl Inst Stand Technol 2005; 110:97-100. [PMID: 27308106 PMCID: PMC4847575 DOI: 10.6028/jres.110.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Accepted: 02/28/2005] [Indexed: 06/06/2023]
Abstract
This paper presents a statistical evaluation of the responsivity data on a number of heat-flux sensors, calibrated using an electrical substitution radiometer as a transfer standard up to 5 W·cm(-2). The sensors, furnished by the customers, were of circular-foil or thermopile type. Comparison of the NIST and the customer measured responsivity values showed that the measurements agree within 3 % for more than half the number of sensors tested, so far. Considering the variation in the customer calibration techniques and the wide measuring range of the sensors used in the calibration, the agreement is encouraging.
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Murthy AV, Wetterlund I, DeWitt DP. Characterization of an Ellipsoidal Radiometer. J Res Natl Inst Stand Technol 2003; 108:115-124. [PMID: 27413598 PMCID: PMC4844513 DOI: 10.6028/jres.108.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Accepted: 03/21/2003] [Indexed: 06/06/2023]
Abstract
An ellipsoidal radiometer has been characterized using a 25 mm variable-temperature blackbody as a radiant source. This radiometer is intended for separating radiation from convection effects in fire test methods. The characterization included angular response, responsivity, and purge-gas flow effect studies. The angular response measurements showed that the reflection from the radiometer cavity was higher on one of the cavity halves relative to the other half. Further development work may be necessary to improve the angular response. The responsivity measured with reference to a transfer-standard electrical-substitution radiometer showed dependence on the distance of the radiometer from the blackbody cavity. The purge-gas had the effect of reducing the signal output nearly linearly with flow rate.
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Affiliation(s)
| | | | - David P DeWitt
- National Institute of Standards and Technology, Gaithersburg, MD 20899-8441
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Murthy AV. Transfer Calibration Validation Tests on a Heat Flux Sensor in the 51 mm High-Temperature Blackbody. J Res Natl Inst Stand Technol 2001; 106:823-31. [PMID: 27500049 PMCID: PMC4862819 DOI: 10.6028/jres.106.039] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 08/01/2001] [Indexed: 06/01/2023]
Abstract
Facilities and techniques to characterize heat flux sensors are under development at the National Institute of Standards and Technology. As a part of this effort, a large aperture high-temperature blackbody was commissioned recently. The graphite tube blackbody, heated electrically, has a cavity diameter of 51 mm and can operate up to a maximum temperature of 2773 K. A closed-loop cooling system using a water-to-water heat exchanger cools electrodes and the outer reflecting shield. This paper describes the newly developed blackbody facility and the validation tests conducted using a reference standard Schmidt-Boelter heat flux sensor. The transfer calibration results obtained on the Schmidt-Boelter sensor agreed with the previous data within the experimental uncertainty limits.
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A. V. Murthy. Comparative Calibration of Heat Flux Sensors in Two Blackbody Facilities. J Res Natl Inst Stand Technol 1999; 104. [ DOI: 10.6028/jres.104.030] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 09/03/1999] [Indexed: 06/01/2023]
Abstract
This paper presents the results of heat flux sensor calibrations in two blackbody facilities: the 25 mm variable temperature blackbody (VTBB) primary facility and a recently developed 51 mm aperture spherical blackbody (SPBB) facility. Three Schmidt-Boelter gages and a Gardon gage were calibrated with reference to an electrical substitution radiometer in the VTBB. One of the Schmidt-Boelter gages thus calibrated was used as a reference standard to calibrate other gages in the SPBB. Comparison of the Schmidt-Boelter gages calibrations in the SPBB and the VTBB agreed within the measurement uncertainties. For the Gardon gage, the measured responsivity in the SPBB showed a gradual decrease with increasing distance from the aperture. When the gage was located close to the aperture, a distance less than the aperture radius, the responsivity in the SPBB agreed with VTBB measurements. At a distance of about three times the aperture radius, the responsivity showed a decrease of about 4 %. This is probably due to higher convection loss from the Gardon gage surface compared to the Schmidt-Boelter sensor.
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Murthy AV, Tsai BK, Saunders RD. Aperture Proximity Effects in High Heat Flux Sensors Calibration. J Res Natl Inst Stand Technol 1998; 103:621-624. [PMID: 28009369 PMCID: PMC4890953 DOI: 10.6028/jres.103.041] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 08/10/1998] [Indexed: 06/01/2023]
Abstract
In the transfer calibration of heat flux sensors, a correction for the irradiance distribution across the sensing area may be required when the sensing areas of the reference and test sensors are different. A method to calculate this correction using well-known equations for the configuration factors is presented. Also, estimates of the correction for test conditions corresponding to the transfer calibration technique in use at the National Institute of Standards and Technology are given.
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Affiliation(s)
| | - B K Tsai
- National Institute of Standards and Technology, Gaithersburg, MD 20899-0001
| | - R D Saunders
- National Institute of Standards and Technology, Gaithersburg, MD 20899-0001
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Abstract
An ongoing program at the National Institute of Standards and Technology (NIST) is aimed at improving and standardizing heat-flux sensor calibration methods. The current calibration needs of U.S. science and industry exceed the current NIST capability of 40 kW/m2 irradiance. In achieving this goal, as well as meeting lower-level non-radiative heat flux calibration needs of science and industry, three different types of calibration facilities currently are under development at NIST: convection, conduction, and radiation. This paper describes the research activities associated with the NIST Radiation Calibration Facility. Two different techniques, transfer and absolute, are presented. The transfer calibration technique employs a transfer standard calibrated with reference to a radiometric standard for calibrating the sensors using a graphite tube blackbody. Plans for an absolute calibration facility include the use of a spherical blackbody and a cooled aperture and sensor-housing assembly to calibrate the sensors in a low convective environment.
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Affiliation(s)
| | - B K Tsai
- National Institute of Standards and Technology, Gaithersburg, MD 20899-0001
| | - C E Gibson
- National Institute of Standards and Technology, Gaithersburg, MD 20899-0001
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