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Fire Environments Typical of Navy ShipsLeBlanc, David 01 May 2002 (has links)
Current test methodologies used to evaluate the performance of protective clothing do not adequately determine the provided level of protection. The heat fluxes imposed by current evaluation methods are not specifically related to fire environments typical to those the clothing is designed provide protection against. The U.S. Navy is in the process of developing an improved process for testing the fire resistance of daily wear uniforms and protective gear. The first phase of this project involves evaluating currently used evaluation methods and identifying the severity of fire environments that would be expected aboard Navy ships. The examination of the test protocols currently in use identifies major weaknesses, providing the justification for a new test protocol. The first step in developing an improved test protocol is to determine the types of fire scenarios that would be expected aboard Navy vessels. The nearly infinite number of possible fires are reduced to 6 typical cases involving spray fires, pool fires and furniture fires in both compartmented and unconfined cases. An analysis of the environments produced by these types of fires is presented. The effects of compartmentation parameters are also investigated to determine the critical factors that affect the expected fire environment. Expected heat fluxes for all scenarios are presented at a number of distances from the fire.
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Ροή θερμότητας στη διεπιφάνεια αέρα-θάλασσας στο Αιγαίο ΠέλαγοςΠαπαδόπουλος, Βασίλης 05 August 2011 (has links)
Στη διατριβή υπολογίζονται μηνιαίες τιμές για κάθε μια από τις τέσσερις συνιστώσες της ροής θερμότητας στη διεπιφάνεια αέρα-θάλασσας σε πέντε σημεία στο Αιγαίο Πέλαγος για το χρονικό διάστημα 2000-2008 με χρήση δεδομένων α) από το δίκτυο πλωτών μετρητικών σταθμών του συστήματος ΠΟΣΕΙΔΩΝ του Ελληνικού Κέντρου Θαλασσίων Ερευνών, β) από τη δορυφορική πλατφόρμα SSM/I και γ) από την Εθνική Μετεωρολογική Υπηρεσία. Οι μηνιαίες τιμές που υπολογίζονται για κάθε μία από τις τέσσερις συνιστώσες της ροής θερμότητας συγκρίνονται με τις αντίστοιχες από ευρέως χρησιμοποιούμενες βάσεις δεδομένων με σκοπό την αξιολόγηση των βάσεων αυτών για την περιοχή του Αιγαίου Πελάγους. Στη συνέχεια χρησιμοποιούνται οι στατιστικά καλύτερες βάσεις για τη διερεύνηση των χαρακτηριστικών της ροής θερμότητας στο Αιγαίο σε βάθος χρόνου. Εξετάζεται η συσχέτιση των συνιστωσών της ροής θερμότητας με γνωστούς και πειραματικούς κλιματικούς δείκτες, με τη μεγάλης κλίμακας ατμοσφαιρική κυκλοφορία και με το πεδίο του υετίσιμου ύδατος σε μια περιοχή που περιλαμβάνει τον ανατολικό Ατλαντικό, την Ευρώπη και τη βόρεια Αφρική. Τέλος εξετάζεται η συνεισφορά και η συμπεριφορά των συνιστωσών στη μεταβλητότητα της ροής θερμότητας μεταξύ αέρα και θάλασσας στο Αιγαίο Πέλαγος καθώς και το πεδίο της ατμοσφαιρικής πίεσης που ευνοεί την εμφάνιση των ακρότατων τιμών της ξεχωριστά για την ψυχρή και τη θερμή περίοδο του έτους. / Monthly mean values for the each one of the four air-sea heat fluxes components are calculated at five sites in the Aegean Sea for the period 2000-2008. For this calculation three different kinds of data are used: a) data from the Greek network of oceanographic buoys of the Hellenic Centre for Marine Research (the POSEIDON system), b) data from the NASA satellite platform SSM/I, and c) data from the Hellenic National Meteorological Service. The calculated monthly mean values are compared with the corresponding values from broadly used data bases in order to investigate the suitability of these data bases for the Aegean Sea. The statistically robust data archives are used to examine the characteristics of the surface fluxes over an extended time period. More specifically, the correlation between the surface heat exchange and several climatic indices, the large scale atmospheric circulation and the total precipitable water are investigated over an extended area covering the eastern part of the Atlantic Ocean, Europe and north Africa. The behavior and the contribution of each air-sea heat fluxes component to surface fluxes variability over the Aegean are also identified. Last, the sea level pressure (SLP) patterns favoring the uppermost and the lowermost air-sea heat budget values are described separately for the cold and for the warm period of the year.
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Observations of wintertime air-sea heat exchange within polynya and lead environments of Amundsen Gulf and the Southeastern Beaufort SeaStammers, Christopher 09 January 2016 (has links)
Direct measurements of wintertime surface heat fluxes between the ocean and atmosphere in lead and polynya environments in the Canadian Arctic are presented. Such environments can yield very large vertical temperature gradients during the winter months and are particularly dynamic micrometeorological environments. We found that sensible heat fluxes can exceed +100 W m-2 during the winter months, much larger than most regional estimates (~ 0 W m-2). In addition, large heat fluxes are shown to affect the characteristics of the near surface temperature inversion (temperature increases with height). The height, depth and strength of the characteristic wintertime inversion are shown to be influenced in cases where large surface fluxes were observed. Such findings are likely to have implications on the regional and planetary heat budget, general circulation models and larger scale weather processes, which most often omit local scale heat fluxes in their analyses and calculations. / February 2016
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Clothing flammability and skin burn injury in normal and micro-gravityCavanagh, Jane M. 30 August 2004
As space exploration has advanced, time spent in space has increased. With the building of the International Space Station and plans for exploration missions to the Moon and Mars, astronauts will be staying in space for longer periods of time. With these increased stays in space comes an increase in fire safety concerns. One area of fire safety interest is flammability. While current flammability test procedures are in place, they are all performed on the ground and may not be representative of flammability in microgravity. In addition to this, limited research into the severity of skin burn injury in a microgravity environment has been performed. <p>An apparatus was designed to be flown on a low gravity parabolic aircraft flight to assess the flammability of cotton and 50% cotton/50% polyester fabrics and the resulting skin burn injury that would occur if these fabrics were to ignite. The apparatus, modelled after a Canadian General Standards Board standard flammability test, was also used on the ground for experiments in 1-g. Variables examined in the tests include gravity level, fabric type, air gap size, oxygen concentration, apparatus orientation, ignition source, and method used to secure the specimen. Flame spread rates, heat fluxes, and skin burn predictions determined from test results were compared. <p>Results from test in 1-g indicated that the orientation of the apparatus had a large effect on flame spread rate, heat flux and predicted skin burn times. Flame spread rates and heat fluxes were highest when the fabric was held in the vertical orientation, which resulted in the lowest predicted times to produce skin burns. Flame spread rates and heat fluxes were considerably lower in microgravity than in 1-g, which resulted in higher predicted times to produce skin burns.
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Clothing flammability and skin burn injury in normal and micro-gravityCavanagh, Jane M. 30 August 2004 (has links)
As space exploration has advanced, time spent in space has increased. With the building of the International Space Station and plans for exploration missions to the Moon and Mars, astronauts will be staying in space for longer periods of time. With these increased stays in space comes an increase in fire safety concerns. One area of fire safety interest is flammability. While current flammability test procedures are in place, they are all performed on the ground and may not be representative of flammability in microgravity. In addition to this, limited research into the severity of skin burn injury in a microgravity environment has been performed. <p>An apparatus was designed to be flown on a low gravity parabolic aircraft flight to assess the flammability of cotton and 50% cotton/50% polyester fabrics and the resulting skin burn injury that would occur if these fabrics were to ignite. The apparatus, modelled after a Canadian General Standards Board standard flammability test, was also used on the ground for experiments in 1-g. Variables examined in the tests include gravity level, fabric type, air gap size, oxygen concentration, apparatus orientation, ignition source, and method used to secure the specimen. Flame spread rates, heat fluxes, and skin burn predictions determined from test results were compared. <p>Results from test in 1-g indicated that the orientation of the apparatus had a large effect on flame spread rate, heat flux and predicted skin burn times. Flame spread rates and heat fluxes were highest when the fabric was held in the vertical orientation, which resulted in the lowest predicted times to produce skin burns. Flame spread rates and heat fluxes were considerably lower in microgravity than in 1-g, which resulted in higher predicted times to produce skin burns.
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Impact of cold climate on boreal ecosystem processes : exploring data and model uncertaintiesWu, Sihong January 2011 (has links)
The impact of cold climate on physical and biological processes, especially the role of air and soil temperature in recovering photosynthesis and transpiration in boreal forests, was investigated in a series of studies. A process-based ecosystem model (CoupModel) considering atmospheric, soil and plant components was evaluated and developed using Generalized Likelihood Uncertainty Estimation (GLUE) and detailed measurements from three different sites. The model accurately described the variability in measurements within days, within years and between years. The forcing environmental conditions were shown to govern both aboveground and belowground processes and regulating carbon, water and heat fluxes. However, the various feedback mechanisms between vegetation and environmental conditions are still unclear, since simulations with one model assumption could not be rejected when compared with another. The strong interactions between soil temperature and moisture processes were indicated by the few behavioural models obtained when constrained by combined temperature and moisture criteria. Model performance on sensible and latent heat fluxes and net ecosystem exchange (NEE) also indicated the coupled processes within the system. Diurnal and seasonal courses of eddy flux data in boreal conifer ecosystems were reproduced successfully within defined ranges of parameter values. Air temperature was the major limiting factor for photosynthesis in early spring, autumn and winter, but soil temperature was a rather important limiting factor in late spring. Soil moisture and nitrogen showed indications of being more important for regulating photosynthesis in the summer period. The need for systematic monitoring of the entire system, covering both soil and plant components, was identified as a subject for future studies. The results from this modelling work could be applied to suggest improvements in management of forest and agriculture ecosystems in order to reduce greenhouse gas emissions and to find adaptations to future climate conditions. / QC 20110921 / the Nitro-Europe project
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Estimativa dos fluxos de calor a partir de imagens orbitais e aplicação na modelagem hidrológica / Estimating heat fluxes from satellite images and application in hydrologic modelingSousa, Adriano Marlisom Leão de January 2010 (has links)
Este estudo visa à estimativa dos fluxos de calor à superfície a partir de imagens orbitais, com os modelos SEBAL/METRIC e aplicação na modelagem hidrológica, com o modelo SWAT. Para isso, foram utilizados os dados da torre micrometeorológica da Ilha do Bananal, coletados durante os Experimentos do LBA, e os dados pluviométricos e fluviométricos. Os dados utilizados compreendem o período de outubro de 2003 a dezembro de 2006 da sub-bacia do rio Lajeado, localizada na bacia do rio Tocantins- Araguaia no estado do Tocantins. O clima na área de estudo tem sazonalidade bem definida, com períodos chuvosos de outubro a março e secos de abril a setembro. As estimativas a partir dos modelos SEBAL/METRIC variaram em função do tipo de solo, com estimativas coerentes dos fluxos de calor à superfície. Em geral, as estimativas dos fluxos de calor representam uma subestimativa de 10% para todo o período estudado. No entanto, sazonalmente observou-se subestimativas de 17% no período chuvoso e de 35% no período seco. De maneira geral, os resultados da utilização da evapotranspiração estimada por sensores remotos no modelo SWAT foi satisfatória. A assimilação da evapotranspiração a partir de imagens orbitais resultou em valores de COE que variaram de 0,57 a 0,84 com os dados diários e de 0,69 a 0,77 com os dados mensais de vazão. Isto indica melhoria no ajuste do modelo, devido a uma melhoria de 0,27 de COE no dado diário e de 0,08 no mensal. Observou-se ainda, que em termos percentuais a vazão simulada pelo modelo SWAT na bacia do rio Lajeado, após a assimilação dos dados de evapotranspiração, apresentou uma redução no erro, de 13% (superestimativa) para 3% (subestimativa) na vazão diária e de 9% para 7% (subestimativa) na vazão mensal. / This study presents estimate of the heat flow to the surface from orbital images with the models SEBAL / METRIC for use in hydrological modeling with the SWAT model. For this, we used data from micrometeorological tower of Island Bananal, collected during the experiments the LBA, rainfall and hydrological data. The data used is defined for the period October 2003 to December 2006, in the State Tocantins of catchments river Tocantins- Araguaia of the basin river Lajeado. We observed that the climate in the study area is seasonally well-defined with the rainy season from October to March and the dry are from April to September. Estimates from the models SEBAL / METRIC, varied according to soil type, are consistent with estimates of heat fluxes to the surface. In general, estimates of heat fluxes indicated underestimate of 10% for the period studied. However, seasonally there was an underestimates of 17% in the rainy season and of 35% in the dry season. The results of the hydrologic model can be judged satisfactory by the COE values which vary from 0.57 to 0.84 when comparing the streamflow daily data and from 0.69 to 0.77 with streamflow monthly data, with assimilation of evapotranspiration. This indicates benefits to the model, because was observed an improvement of 0.27 in the COE as daily and of 0.08 as monthly. It was also observed that in percentage terms the streamflow simulated by the SWAT model in the basin river Lajeado after the assimilation of evapotranspiration data showed a reduction error of 13% (overestimation) to 3% (underestimate) to the daily flow and from 9% to 7% (underestimate) to the monthly flow.
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Estimativa dos fluxos de calor a partir de imagens orbitais e aplicação na modelagem hidrológica / Estimating heat fluxes from satellite images and application in hydrologic modelingSousa, Adriano Marlisom Leão de January 2010 (has links)
Este estudo visa à estimativa dos fluxos de calor à superfície a partir de imagens orbitais, com os modelos SEBAL/METRIC e aplicação na modelagem hidrológica, com o modelo SWAT. Para isso, foram utilizados os dados da torre micrometeorológica da Ilha do Bananal, coletados durante os Experimentos do LBA, e os dados pluviométricos e fluviométricos. Os dados utilizados compreendem o período de outubro de 2003 a dezembro de 2006 da sub-bacia do rio Lajeado, localizada na bacia do rio Tocantins- Araguaia no estado do Tocantins. O clima na área de estudo tem sazonalidade bem definida, com períodos chuvosos de outubro a março e secos de abril a setembro. As estimativas a partir dos modelos SEBAL/METRIC variaram em função do tipo de solo, com estimativas coerentes dos fluxos de calor à superfície. Em geral, as estimativas dos fluxos de calor representam uma subestimativa de 10% para todo o período estudado. No entanto, sazonalmente observou-se subestimativas de 17% no período chuvoso e de 35% no período seco. De maneira geral, os resultados da utilização da evapotranspiração estimada por sensores remotos no modelo SWAT foi satisfatória. A assimilação da evapotranspiração a partir de imagens orbitais resultou em valores de COE que variaram de 0,57 a 0,84 com os dados diários e de 0,69 a 0,77 com os dados mensais de vazão. Isto indica melhoria no ajuste do modelo, devido a uma melhoria de 0,27 de COE no dado diário e de 0,08 no mensal. Observou-se ainda, que em termos percentuais a vazão simulada pelo modelo SWAT na bacia do rio Lajeado, após a assimilação dos dados de evapotranspiração, apresentou uma redução no erro, de 13% (superestimativa) para 3% (subestimativa) na vazão diária e de 9% para 7% (subestimativa) na vazão mensal. / This study presents estimate of the heat flow to the surface from orbital images with the models SEBAL / METRIC for use in hydrological modeling with the SWAT model. For this, we used data from micrometeorological tower of Island Bananal, collected during the experiments the LBA, rainfall and hydrological data. The data used is defined for the period October 2003 to December 2006, in the State Tocantins of catchments river Tocantins- Araguaia of the basin river Lajeado. We observed that the climate in the study area is seasonally well-defined with the rainy season from October to March and the dry are from April to September. Estimates from the models SEBAL / METRIC, varied according to soil type, are consistent with estimates of heat fluxes to the surface. In general, estimates of heat fluxes indicated underestimate of 10% for the period studied. However, seasonally there was an underestimates of 17% in the rainy season and of 35% in the dry season. The results of the hydrologic model can be judged satisfactory by the COE values which vary from 0.57 to 0.84 when comparing the streamflow daily data and from 0.69 to 0.77 with streamflow monthly data, with assimilation of evapotranspiration. This indicates benefits to the model, because was observed an improvement of 0.27 in the COE as daily and of 0.08 as monthly. It was also observed that in percentage terms the streamflow simulated by the SWAT model in the basin river Lajeado after the assimilation of evapotranspiration data showed a reduction error of 13% (overestimation) to 3% (underestimate) to the daily flow and from 9% to 7% (underestimate) to the monthly flow.
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Estimativa dos fluxos de calor a partir de imagens orbitais e aplicação na modelagem hidrológica / Estimating heat fluxes from satellite images and application in hydrologic modelingSousa, Adriano Marlisom Leão de January 2010 (has links)
Este estudo visa à estimativa dos fluxos de calor à superfície a partir de imagens orbitais, com os modelos SEBAL/METRIC e aplicação na modelagem hidrológica, com o modelo SWAT. Para isso, foram utilizados os dados da torre micrometeorológica da Ilha do Bananal, coletados durante os Experimentos do LBA, e os dados pluviométricos e fluviométricos. Os dados utilizados compreendem o período de outubro de 2003 a dezembro de 2006 da sub-bacia do rio Lajeado, localizada na bacia do rio Tocantins- Araguaia no estado do Tocantins. O clima na área de estudo tem sazonalidade bem definida, com períodos chuvosos de outubro a março e secos de abril a setembro. As estimativas a partir dos modelos SEBAL/METRIC variaram em função do tipo de solo, com estimativas coerentes dos fluxos de calor à superfície. Em geral, as estimativas dos fluxos de calor representam uma subestimativa de 10% para todo o período estudado. No entanto, sazonalmente observou-se subestimativas de 17% no período chuvoso e de 35% no período seco. De maneira geral, os resultados da utilização da evapotranspiração estimada por sensores remotos no modelo SWAT foi satisfatória. A assimilação da evapotranspiração a partir de imagens orbitais resultou em valores de COE que variaram de 0,57 a 0,84 com os dados diários e de 0,69 a 0,77 com os dados mensais de vazão. Isto indica melhoria no ajuste do modelo, devido a uma melhoria de 0,27 de COE no dado diário e de 0,08 no mensal. Observou-se ainda, que em termos percentuais a vazão simulada pelo modelo SWAT na bacia do rio Lajeado, após a assimilação dos dados de evapotranspiração, apresentou uma redução no erro, de 13% (superestimativa) para 3% (subestimativa) na vazão diária e de 9% para 7% (subestimativa) na vazão mensal. / This study presents estimate of the heat flow to the surface from orbital images with the models SEBAL / METRIC for use in hydrological modeling with the SWAT model. For this, we used data from micrometeorological tower of Island Bananal, collected during the experiments the LBA, rainfall and hydrological data. The data used is defined for the period October 2003 to December 2006, in the State Tocantins of catchments river Tocantins- Araguaia of the basin river Lajeado. We observed that the climate in the study area is seasonally well-defined with the rainy season from October to March and the dry are from April to September. Estimates from the models SEBAL / METRIC, varied according to soil type, are consistent with estimates of heat fluxes to the surface. In general, estimates of heat fluxes indicated underestimate of 10% for the period studied. However, seasonally there was an underestimates of 17% in the rainy season and of 35% in the dry season. The results of the hydrologic model can be judged satisfactory by the COE values which vary from 0.57 to 0.84 when comparing the streamflow daily data and from 0.69 to 0.77 with streamflow monthly data, with assimilation of evapotranspiration. This indicates benefits to the model, because was observed an improvement of 0.27 in the COE as daily and of 0.08 as monthly. It was also observed that in percentage terms the streamflow simulated by the SWAT model in the basin river Lajeado after the assimilation of evapotranspiration data showed a reduction error of 13% (overestimation) to 3% (underestimate) to the daily flow and from 9% to 7% (underestimate) to the monthly flow.
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Etude des champs de flux thermique sur les composants faisant face au plasma dans un tokamak à partir de mesures de température par thermographie infrarouge / Study of heat fluxes on plasma facing components in a tokamak from measurements of temperature by infrared thermographyDaviot, Ronan 19 May 2010 (has links)
La connaissance des champs de flux thermique sur les composants d’un tokamak estun élément important de la conception de ce type de machines. L’objectif de cette thèse est dedévelopper et mettre en œuvre une méthode de calcul de ces flux à partir des mesures detempérature par thermographie infrarouge. Ce travail repose sur trois objectifs qui concernentles tokamaks actuels et futurs (ITER) : mesurer un champ de température d'une paroiréfléchissante par pyrométrie photothermique (pré-étude), caractériser les propriétésthermiques des dépôts sur les surfaces des composants et développer un calcultridimensionnel et non-linéaire du flux.Une comparaison de différentes techniques de pyrométries monochromatique,bichromatique et photothermique est effectuée sur une expérience de laboratoire de mesure detempérature. Une sensibilité importante de la technique de pyrométrie photothermique auxgradients de température sur la zone observée a été mise en évidence.Les dépôts en surface des composants exposés au plasma, sans inertie thermique, sontmodélisés par des champs de résistance thermique équivalente transverse. Ce champ derésistance est déterminé, en tout point de mesure, par confrontation du champ de températurede paroi issu de la thermographie avec le résultat d’une simulation par un modèlemonodimensionnel linéaire du composant. Une information sur la répartition spatiale du dépôtà la surface d’un composant est alors obtenue.Un calcul tridimensionnel et non-linéaire du champ de flux pariétal sur un composantest développé, par une méthode d’éléments finis, à partir de maillages de composants issus deCAO. La sensibilité du flux calculé à la précision des mesures de températures est discutée.Cette méthode est appliquée à des campagnes de mesures de températurebidimensionnelles par thermographie infrarouge sur des composants du tokamak JET. Leschamps de flux sur les tuiles du divertor, la protection supérieure et les protections poloïdalesinternes et externes sont déterminés et étudiés dans les deux directions, poloïdale ettoroïdale, du tokamak. La symétrie toroïdale du flux, d’une tuile à l’autre, est établie.L’influence de la résolution spatiale des mesures sur les flux calculés est discutée, à partir decomparaisons de résultats obtenus à partir de deux systèmes de thermographie de résolutionsdifférentes. / Knowing the fields of heat fluxes on the components of a tokamak is a key element todesign these devices. The goal of this thesis is the development of a method of computation ofthose heat loads from measurements of temperature by infrared thermography. The researchwas conducted on three issues arising in current tokamaks but also future ones like ITER: themeasurement of temperature on reflecting walls, the determination of thermal properties fordeposits observed on the surface of tokamak’s components and the development of a threedimensional,non-linear computation of heat loads.A comparison of several means of pyrometry, monochromatic, bichromatic andphotothermal, is performed on an experiment of temperature measurement. We show that thismeasurement is sensitive to temperature gradients on the observed area.Layers resulting from carbon deposition by the plasma on the surface of componentsare modeled through a field of equivalent thermal resistance, without thermal inertia. Thefield of this resistance is determined, for each measurement points, from a comparison ofsurface temperature from infrared thermographs with the result of a simulation, which isbased on a mono-dimensional linear model of components. The spatial distribution of thedeposit on the component surface is obtained.Finally, a three-dimensional and non-linear computation of fields of heat fluxes, basedon a finite element method, is developed here. Exact geometries of the component, releasedfrom CAD’s design, are used. The sensitivity of the computed heat fluxes is discussedregarding the accuracy of the temperature measurements.This computation is applied to two-dimensional temperature measurements of the JETtokamak. Several components of this tokamak are modeled, such as tiles of the divertor, upperlimiter and inner and outer poloïdal limiters. The distribution of heat fluxes on the surface ofthese components is computed and studied along the two main tokamak’s directions, poloidaland toroidal. Toroidal symmetry of the heat loads from one tile to another is shown. Theinfluence of measurements spatial resolution on the calculated heat fluxes is discussed bycomparing results obtained from measurements of two systems of thermography.
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