Academic literature on the topic 'Sol-Air Temperatures'

Thin films of lithium ion conductive ceramic Li4+xAlxSi1-xO4 were fabricated on Au substrate using sol-gel process. The sol of Li-Al-Si-O was spread on Au substrate using a spin coater, and it was gelated at room temperature. The gel was calcinated at 400 °C and heat-treated at high temperatures between 500 °C and 800 °C in air. The addition of poly(vinylpyrrolidone) (PVP) was effective in stabilizing the sol. Furthermore, the morphology of the obtained thin film was changed by the PVP additive. Li4+xAlxSi1-xO4 thin film prepared at 800 °C exhibited a Li+ ion conductivity of 10-8 S cm-1 at room temperature.

Using tetraethoxysilane (TEOS) and novolac-PF as raw materials, SiO2/PF hybrid fibers were prepared via sol-gel associated with drawing process, and then sintered at different temperatures (500-1300 °C) under air atmosphere. The microstructure variation and reaction mechanism of the fiber were investigated by FT-IR, XRD, and SEM measurements. The results showed that the microstructure variation of the hybrid fiber was influenced greatly by sintering temperatures. When the sintering temperature was below 900 °C, the fibers were amorphous, and converted into porous SiO2/SiC fibers after being sintered at 1300 °C.

This paper describes microstructure characteristics of MgAl2O4 thin films were deposited by sol-gel method with various preheating temperatures and annealing temperatures. Particular attention will be paid to the effects of a thermal treatment in air ambient on the physical properties. The annealed films were characterized using X-ray diffraction. The surface morphologies of treatment film were examined by scanning electron microscopy and atomic force microscopy. At a preheating temperature of 300oC and an annealing temperature of 700oC, the MgAl2O4 films with 9 μm thickness possess a dielectric constant of 9 at 1 kHz and a dissipation factor of 0.18 at 1 kHz.

The crystallization of bulk amorphous SiO2 samples, prepared by the sol-gel method, was obtained by heat treatments in air at temperatures as low as 500 °C. This occurs when silver is added to the precursor solutions in an amount such that it forms aggregates embedded in the glass. Another requirement to observe the low-temperature glass crystallization is that the bulk samples must be prepared from precursor solutions with specific compositions. These compositions, have a high H2O/TEOS ratio, which produces an amorphous SiO2 structure with some structural similarities to cristobalite, the phase in which the SiO2 glass crystallizes.

This paper describes microstructure characteristics of MgAl2O4 thin films were deposited by sol-gel method with various annealing temperatures. Particular attention will be paid to the effects of an annealing treatment in air ambient on the physical properties. The annealed films were characterized using X-ray diffraction. The surface morphologies of annealed film were examined by scanning electron microscopy and atomic force microscopy. The dependence of the dielectric properties and microstructure characteristics on annealing temperature was also investigated.

Highly photoactive ZnO thin films on glass substrates and quartz substrates have been prepared by sol-gel process. Structural features, surface morphology and UV absorption spectrum have been studied by XRD, SEM and UV-Vis scanning spectrophotometer. The influence of degradation temperatures, original concentration of phenol and air flux on degradation rates have also been studied. And the results show the best conditions, degradation temperature is between 25oC and 45 oC, air flux is 40ml/min, the lower original concentration, the higher degradation rates. Excellent adhesion as well as recyclable and efficient in phenol degradation of ZnO thin films were found in this experiment.

This paper describes physical properties of (Ca0.8Sr0.2)TiO3 were deposited by sol-gel method with a fix per-heating temperature of 400oC for 60 min at various annealing temperatures from 600oC to 700oC for 60 min. Particular attention will be paid to the effects of an annealing treatment in air ambient on the physical properties. The annealed films were characterized using X-ray diffraction (XRD). The surface morphologies of annealed film were examined by atomic force microscopy and scanning electron microscopy.

Using infrared absorption and Raman spectroscopy, the structure of SiO2 sol-gel samples containing copper were analyzed as a function of air heat treatments. The weight composition of the samples was 70(SiO2)–30(CuO) and the thermal treatments were carried out in air at various temperatures in the range of 100–600 °C. It was found that the Cu might be incorporated into the SiO2 matrix at least in two ways: forming oxide particles and forming metasilicatelike structures. The copper metasilicate found had the chemical formula, Cu6 [Si6O18] · 6H2O, which is known as dioptase with a thermal stability at temperatures up to 600 °C.

Thin SiO2ZrO2films were prepared, up to 0.2 μm thick, by means of the sol–gel technology and characterized by a Scanning electron microscopy and X-ray diffraction. It is shown the presence of monoclinic, cubic and tetragonal phases of ZrO2in the SiO2matrix. The crystallites sizes depend on the annealing temperature of the film and amount to 35 and 56 nm for the films annealed at 773 and 973 K, respectively. The films resistance is rather sensitive to the presence of NO2and O3impurity in air at lower operating temperatures in the range of 30-60°C.

Nanocrystalline of Barium Hexaferrite (BaFe12O19) powders have been synthesized using the sol gel auto combustion method. The ferrite precursors were obtained from aqueous mixtures of Barium nitrate and Ferric nitrate by auto combustion reaction from gel point. These precursors were sintered at different temperatures ranging from 700 to 1000oC for constant calcinations time 2,5 h in a static air atmosphere. Effects of Fe3+/Ba2+ mol ratios and sintering temperatures on the microstructure and magnetic properties were systematically studied. The powders formed were investigated using X-ray diffraction (XRD), scanning electron microscope (SEM) and VSM. The results obtained showed that the phase BaFe12O19 powders were achieved by the Fe3+/Ba2+ mole ratio from the stoichiometric value 11, 11.5 and 12 at temperature950OC. With increasing of temperature sintering, coercivity and magnetization value tends to rising. The maximum saturation magnetization (66.16 emu/g) was achieved at the Fe3+/Ba2+mole ratio to 11.5 and the sintering temperature 950OC. The maximum coercivity value 3542 Oe achieved at mole ratio sample 12 with sintering temperature 950OC. Maximum saturation 6616 emu/g achieved at mole ratio sample 115 with the same temperature.

Le code Submeso est développé dans le but de comprendre et d'analyser les phénomènes d'inversion thermique dans les vallées encaissées. Les grandes échelles de l'écoulement (LES) sont obtenues par la résolution des équations tridimensionnelles du mouvement écrites sous leur forme compressible et non-hydrostatique en coordonnées dites gal-chen. Un modèle sous-maillé basé sur une équation de transport de l'énergie cinétique turbulente permet de transférer la production d'énergie turbulente générée au sol vers les couches supérieures de l'atmosphère. Les échanges entre le sol et l'atmosphère sont décrits par un modèle de sol (sm2-isba), couplé à un modèle de paroi performant. Le modèle de sol est validé sur deux campagnes de mesures sur site efeda et hapex - mobilhy. La prise en compte de l'interaction sol-atmosphère a été validée par deux études de la couche limite planétaire: une couche limite atmosphérique pleinement convective et l'évolution d'une couche limite planétaire correspondant à l'expérience de Wangara. Une étude complète de la structure des écoulements atmosphériques dans des vallées encaissées est réalisée. Dans un premier temps, on étudie l'évolution temporelle d'un scalaire passif émis dans un relief complexe 3D avec des échanges sol-atmosphère simplifiés. Puis, les phénomènes d'inversions thermiques sont étudiés dans une vallée stylisée, pour deux saisons. Le modèle réaliste des échanges sol-atmosphère a permis de simuler le cycle diurne complet. On met en évidence une variabilité saisonnière du comportement de l'inversion. L'été, les phénomènes ont une durée de vie et des périodes de transition plus longue qu'en hiver. Contrairement au cas hivernal, la structure spatiale de la couche convective estivale est symétrique par rapport à l'axe médian de la vallée.

abstract: The aim of this research study is to develop a passive architectural design morphology, tuned to the Sonoran Desert, which redefines Desert Modernism and integrates: (a) mitigation of heat transfer through the exterior envelope, and (b) use of daylight to inform appropriate architectural massing. The research investigation was delimited to mid-nineteenth century European modernist examples, and ends with mid-twentieth century modern architecture in the southwestern United States as viewed through the lens of environmental design. The specific focus was on Desert Modernism, a quasi-architectural movement, which purportedly had its beginnings in 1923 with the Coachella Valley, Popinoe Desert Cabin. A mixed-method research strategy comprised of interpretive-historical research, virtual simulation/modeling analysis and logical argumentation is used. Succinct discussions on desert vernacular design, Modernism’s global propagation, and the International Style reinterpretations were illustrated to introduce the possibility of a relationship between Modernism and the vernacular. A directed examination of climatic responses included within examples of California Modernism, the Case Study Houses and Desert Modernism follows. Three case studies: a) the Frey House II, b) the Triad Apartments, and c) the Analemma House were assessed using virtual simulation and mathematical calculations, to provide conclusive results on the relevance of regionally tuned exterior envelope design and planning tactics for the Phoenix, Arizona area. Together, these findings suggest a correlation between environmental design principles, vernacular architecture, and Modernism.
Dissertation/Thesis
Doctoral Dissertation Architecture 2019

On dénombre divers modèles de simulation de la mouche du chou (Delia radicum L.), mais plusieurs comportent d’importantes lacunes au niveau des différences génotypiques de l’insecte et des paramètres utilisés. L’objectif principal de ce projet est de rassembler les informations manquantes afin de créer dans le futur un modèle bioclimatique permettant de simuler efficacement la dynamique des populations de ce ravageur. L’effet de la température et de l’humidité du sol a été mesuré sur les œufs et les larves de la mouche du chou. L’humidité n’influence la survie des œufs qu’en dessous de 25% [m/m]. L’exposition graduelle des œufs à des températures élevées au dessus de 33°C affecte également la survie. La survie des larves augmente avec la hausse des températures et de l’humidité. Nous croyons que la mouche du chou est bien adaptée aux conditions des sols organiques au Québec, et nous recommandons l’intégration de la température du sol pour les stades au sol plutôt que de l’air dans l’élaboration d’un nouveau modèle. La ponte a également été étudiée à partir de différents critères préétablis pour chacun des génotypes hâtifs et tardifs, à différentes températures. Excepté pour la pré-oviposition qui est plus longue chez les hâtifs, aucune différence n’a été observée entre les génotypes. La majorité des critères, excepté la durée d’un épisode de ponte et la mortalité des œufs, a réagit à la température. Les nouvelles informations serviront à l’élaboration ou le perfectionnement d’un modèle de simulation de la dynamique de la ponte de la mouche du chou.
Few simulation models for the cabbage maggot (Delia radicum L.) had been seen, but several include significant weaknesses for the insect genotypic differences and parameters used. The main objective of this project is to collect the missing information to create, in the future, a bioclimatic model that will efficiently simulate the dynamics of the populations of this pest. The effect of soil temperature and moisture had been measured on eggs and larvae of the cabbage maggot. Humidity affects egg survival below 25% [w/w]. Gradual exposure of eggs to high temperature above 33°C also affects survival. Under tested conditions, larvae survival increases with rising temperatures and humidities. We believe that the maggot is well adapted to muck soil in Quebec, and we recommend to incorporated soil temperature rather than air temperature for above-ground stages into the development of a new model. Egg-laying activity has also been studied from various pre-established criterions for each of the early- and late-emerging genotypes, at different temperatures. Except for the pre-oviposition which is longer for the early genotype, no differences were observed between genotypes. The majority of criterions, except for the duration of oviposition bouts and egg mortality, responded to temperature. The new information will be used for the preparation and development of a simulation model of the egg-laying dynamic of the cabbage maggot.
Réalisé en cotutellle avec Gaétan Bourgeois et avec la participation de Guy Boivin, d'Agriculture et Agroalimentaire Canada, du Centre de Recherche et Développement en Horticulture à Saint-Jean-sur-Richelieu, QC J3B 3E6, Canada

Le biome boréal, emmagasinant d’importantes quantités de carbone en son sol et recouvrant une majorité du territoire alaskien, fennoscandien et russe, contribue grandement au système climatique. Toutefois, les variabilités climatiques et les propriétés de l’écosystème, notamment en ce qui a trait à la présence ou l’absence de pergélisol, complexifient la quantification de la variabilité des bilans de carbone du biome boréal, au sein duquel se retrouvent des écosystèmes forestiers, lentiques et de zones humides. Ces bilans de carbone sont grandement influencés par le début et la fin de la saison de croissance photosynthétique, étant à leur tour dépendants de plusieurs variables environnementales telles que la température de l’air et du sol, le contenu du sol en eau, les stades de développement de la végétation, etc. Cette recherche vise à quantifier l’impact de ces variabilités environnementales sur la variabilité des moments où se produisent le début et la fin de la saison de croissance photosynthétique, en distinguant les forêts boréales avec et sans pergélisol. La saison de croissance photosynthétique est caractérisée à partir de la productivité primaire brute dérivée de mesures covariance des turbulences provenant de 40 sites-années d’observation à travers la forêt boréale nord-américaine où l’épinette noire est l’espèce d’arbre dominante. Les variables environnementales considérées étaient les températures de l’air et du sol, les stades de développement de la végétation, le couvert nival, le rayonnement photosynthétiquement actif et le contenu du sol en eau. Le cadre statistique choisi incluait le calcul des coefficients de corrélations de Pearson, l’analyse des points communs et la modélisation par équations structurelles. Les résultats de cette étude montrent que la variabilité du début de la saison de croissance dans les sites sans pergélisol est contrôlée directement par la variabilité annuelle des stades de développement de la végétation ainsi que par le moment où survient le dégel du sol. Ce résultat souligne ainsi l’importance de l’accès à l’eau liquide du sol afin que la végétation initie la photosynthèse. Aucune variable environnementale ne pouvait significativement expliquer le contrôle du début de la photosynthèse au sein des sites avec pergélisol. À l’automne, le contenu du sol en eau ainsi que le début du couvert nival influencent directement la variabilité de la fin de la saison de croissance photosynthétique. Il est alors montré que la disponibilité de l’eau peut mener à une cessation plus hâtive de la photosynthèse à l’automne. L’effet de l’apparition du couvert nival est quant à lui opposé dans les sites avec et sans pergélisol. Son retard dans les sites sans pergélisol témoigne d’une température de l’air suffisamment élevée pour que les précipitations tombent sous forme liquide, prolongeant ainsi les activités photosynthétiques. Son retard dans les sites avec pergélisol signifie plutôt des précipitations neigeuses moindres, retardant ainsi l’apparition d’une couche isolante pour le sol, qui aurait pu allonger la saison de croissance photosynthétique. Cette étude contribue à clarifier les processus contrôlant le début et la fin de la saison de croissance photosynthétique et aidera à améliorer la compréhension des effets des changements climatiques sur la force du puits de carbone de la forêt boréale nord-américaine.
The boreal forest, storing large amounts of carbon in its soil and covering a majority of the Alaskan, Canadian, Fennoscandian and Russian territory, is an integral part of the climate system. However, climatic variability and ecosystem properties, particularly with regards to the presence or absence of permafrost, limits our understanding of the carbon balance variability in the boreal biome, which comprises forest, lake and wetland ecosystems. The boreal carbon sink-source strength is greatly influenced by phenological events, including the start and end of the photosynthetic growing season, which are themselves dependent on several environmental variables such as air and soil temperature, soil water content, vegetation development stages, etc. This research aims to provide new insights on the influence of environmental variability on the variability in the timing of the photosynthetic growing season, by broadly distinguishing between boreal forests with and without permafrost. The photosynthetic growing season is characterized using gross primary productivity derived from eddy covariance measurements of net ecosystem carbon dioxide exchange. Data from 40 black spruce- dominated site-years of observation across the North American boreal forest are used. The considered environmental predictors were air and soil temperatures, vegetation development stages, snow cover, photosynthetically active radiation and soil water content. The statistical framework included the calculation of Pearson correlation coefficients, commonality analyses and structural equation modeling. This study shows that the variability in the start of the growing season in permafrost-free sites is directly controlled by the variability in vegetation development stage as well as by the thawing of seasonally frozen ground. This result thus emphasizes the importance of access to liquid soil water for the vegetation to initiate photosynthesis. No environmental variable could significantly explain photosynthesis recovery in sites with permafrost. In fall, the soil water content as well as the start of snow cover directly influence the variability in the end of the photosynthetic growing season. These results suggest that the availability of water can limit photosynthesis in the fall. The effect of snow cover is opposite in sites with and without permafrost. A delay in the appearance of continuous snow cover in sites without permafrost indicates that the air temperature is high enough for precipitation to fall in liquid form and for photosynthesis to continue. In contrast, its delay in sites with permafrost indicates less snowfall, thus delaying the appearance of an insulating layer for the soil, which could have lengthened the photosynthetic growing season. This study sheds light on the controls of the annual variation of the timing of the photosynthetic growing season and will help understanding of the effects of climate change on the strength of the North American boreal forest carbon sink.

High temperature integrated ultrasonic transducers (IUTs) made of thick piezoelectric composite films have been coated directly onto the lubricant oil supply and sump lines of a modified CF700 turbojet engine. These thick piezoelectric films are fabricated using a sol-gel spray technology. The center frequencies of these IUTs are in the range of 10 to 12 MHz. The top electrodes, electrical wires, conducting adhesive bond, connectors and cables have been tested successfully for temperatures of up to 500°C. By operating these IUT in transmission mode, the amplitude and velocity of transmitted ultrasonic waves across the flow channel of the lubricant oil in supply and sump lines were measured during engine operation. The results have shown that the strength of the ultrasonic waves is sensitive to the presence of air bubbles in the oil and that the ultrasound velocity is linearly dependent on oil temperature. Based on the sensitivity of ultrasound velocity to oil temperature, a method for real-time monitoring of engine oil degradation is proposed.

The production of oil mist in machinery processing workshop is harmful. To control concentration of oil mist, the TiO2 which can treat with manifold organic pollutants is used to purify oil mist. At first, the nanometer TiO2 is prepared using the sol-gel method on the optimum formulation that showed a higher activity. Then it is treated by dip-coating technique using the non-woven fabric as composite support. The efficiency of suppression of oil mist is compared with ordinary materials. With the increase of time, the purification of the nanometer TiO2 photocatalyst sieve against oil mist of non-woven fabric is investigated in solar radiation at room temperature. It oxidizes pollutants of oil mist to CO2 and H2O. The experiments demonstrat oil mist is oxidized on the TiO2 sol at the 22nd minute with a maximum capacity of 0.3219g. It infers from the experiments the photodegradation effect is high and the reaction is fast. It also concludes that the nanometer TiO2 photocatalysis material is an ideal material for suppressing oil mist in air. At last, a status the application of technology in air purification as well as its problems and trends are presented. The technique has a promising prospect to solve the increasing air problem of the workshop.

Each microstructured stainless steel foil was brazed in vacuum for stacking. Inner surface of micro channels was coated with Al2O3 layer to support Pt catalyst by sol-gel method. The stack was designed like a cross-flow type heat exchanger to perform the combination of exothermic and endothermic reactions simultaneously. It is expected to apply to the micro reformer which produces hydrogen for micro PEMFC (Proton Exchange Membrane Fuel Cell). As the first step in our study, we measured experimentally the heat transfer rate and the spatial temperature distribution of the stack. An then, the reaction of C3H8-air with heat transfer to cold air flow was performed in the stack. As a consequence, quantitative and qualitative thermal characteristics of the stack for reaction were investigated.

Indoor air pollution seriously threats the life and health of human beings. The improvement of indoor air quality has become a focus that people pay more and more attentions to. The photocatalytic of pollutants based on TiO2 is a promising air purification technology. In order to overcome the disadvantages of nanometer powder TiO2 catalyst and to enhance the photocatalytic activity of TiO2, series of glass plates covered with doped-TiO2 were prepared and the photocatalysis them were studied. The glass plates covered with TiO2 which was doped in advance with N, F, or/and Fe were prepared by a sol-gel method. The doping content of N, F, Fe and heat treatment temperature were determined using the orthogonal array of the Taguchi quality design. The prepared gel was coated on the glass by spin-coating method. The effects of doping level of N, F and Fe and heat treatment temperature on the photocatalytic capabilities were investigated. The photocatalytic capabilities of prepared glass plates were investigated by degrading the solution of methylene blue (MB,C16H18ClN3S). The results show that appropriate addition of N, F and Fe and temperaturae are effective for improving the photocatalytic activities of TiO2 under visible light. The optimal TiO2 was prepared under the condition that the doping amount of F element was 9at %, that of N is 7at %, and none of Fe under 400 °C calcination temperature. The degradation rate of the sample for methylene blue solution reaches 23.49% under visible light irradiation for 5 hours. The influence order of the factors was the calcination temperature > F > N > Fe.

Photocatalytic reduction of contaminants in wastewater or polluted water can be enhanced by finding a suitable catalyst with property that utilizes an extended light adsorption spectrum, reducing the recombination of electron-hole pairs, and casting the catalyst into a form with large surface-to-volume ratio to be in contact with the contaminants. Based on these objectives, Zn-doped TiO2 nanoparticles with high photocatalytic activity were synthesized by the sol–gel assisted nozzle-less electrospinning technique followed by calcining the precursor Ti(OiPr)4/ZnAc/PVP nanofibers in air in the temperature range of 450–650°. The thermal decomposition behavior was studied by thermogravimetric analyser and differential scanning calorimeter (TGA–DSC), and the morphology and crystal structure were monitored by scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD). With the different concentration of zinc acetate in the precursor solution, the diameter of fibers ranged from 80–130 nm. The photocatalytic degradation of rhodamine B dye under visible light irradiation was also studied. It is found that the photosensitized degradation activity can be optimized by doping an appropriate amount of Zn (0.30 wt. %). Hence, the enhanced photodegradation of dyes with a new photocatalyst nanofiber under visible irradiation can be realized, which can take better use of solar energy.