Littérature scientifique sur le sujet « Damp chambers »
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Articles de revues sur le sujet "Damp chambers"
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Bonde, M. R., S. E. Nester et C. L. Palmer. « Longevity of Uromyces transversalis, Causal Agent of Gladiolus Rust, under Various Environmental Conditions ». Plant Health Progress 16, no 2 (janvier 2015) : 52–55. http://dx.doi.org/10.1094/php-rs-14-0036.
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To help determine if gladiolus rust may spread to new areas of the United States, we studied effects of different temperature and moisture conditions on longevity of Uromyces transversalis urediniospores. Treatments consisted of gladiolus leaf pieces, with actively sporulating uredinia, placed in mesh bags in a plastic beaker without soil (dry) or plastic bags covered in damp soil (damp). These treatments were either held in a greenhouse at 22–26°C (warm) or refrigerator at 4°C (cool). After 14 days, 59% of urediniospores maintained under warm, dry conditions were viable compared to only 1% under warm damp conditions. After 56 days, viability dropped to 3% and near 0%, respectively. Under cool conditions, by 91 days germination dropped to 0.7% and 0%, respectively. To determine the potential for corms or soilless mix from infected plants to harbor inoculum, infected gladiolus plants were maintained in a growth chamber progressively simulating fall and winter. Following foliage senescence, corms from infected plants were removed from the soilless mix, stored 11 months at 4°C, and planted in noninfested soilless mix in the greenhouse. The pots containing soilless mix in growth chambers, upon removal of corms present on infected plants, were maintained in the chambers until fall and then replanted with healthy corms. No pustules developed on either set of plants, indicating that corms from infected plants had not been infected, urediniospores had not survived in the soilless mix, and urediniospores on or in soil did not perpetuate the disease. Accepted by publication 15 January 2015. Published 6 April 2015.
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Wei, Gang, Min Xiao, Heng Yi Xia, Lin Yao et Yue Lin Tang. « Mobile Maintenance Room of GIS Equipment at the Voltage Class of 220kV ». Applied Mechanics and Materials 713-715 (janvier 2015) : 1360–63. http://dx.doi.org/10.4028/www.scientific.net/amm.713-715.1360.
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According to data about GIS breakdown maintenance in Maintenance Branch of State Grid Chongqing Electric Power Company during recent years, GIS accident of Chongqing Electric Power Company that happens every year is internal fault of local air chambers (such as breaker, PT and bus) in most cases. Once accident happens, a high requirement will be proposed for water prevention and damp prevention at the site during either on-site inspection for the accident cause or replacement for the damaged equipment. In order to effectively cover the first hole of the opened GIS air chamber and make the operation environment meet rain-proof and damp-proof requirements during internal examination for GIS air chamber, a design scheme of mobile GIS maintenance room is proposed in this paper. SF6 detection equipment as well as temperature and humidity examination equipment is installed in the maintenance room, so as to measure multiple parameters and to guarantee light transmission, ventilation and fire resistance. It is convenient for installation and disassembly, and the space can be adjusted. It is suitable for GIS equipment maintenance at the voltage class of 220kV.
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Ananda, K., et K. R. Sridhar. « Diversity of endophytic fungi in the roots of mangrove species on the west coast of India ». Canadian Journal of Microbiology 48, no 10 (1 octobre 2002) : 871–78. http://dx.doi.org/10.1139/w02-080.
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Because mangrove plant species are a valuable source of useful metabolites, their endophytes have gained more importance. Randomly sampled surface-sterilized whole root segments of four mangrove plant species, Acanthus ilicifolius, Avicennia officinalis, Rhizophora mucronata, and Sonneratia caseolaris from the mangroves of Udyavara (Karnataka) on the west coast of India, were characterized for fungal communities by direct plating, damp chamber, and bubbling chamber incubation methods. The richness of endophytic fungal species from whole root segments after direct plating and damp chamber incubation was greatest for R. mucronata than for other plants (18 vs. 813). Incubation of whole root segments in bubbling chambers yielded conidia of two freshwater hyphomycetes: Mycocentrospora acerina (in Avicennia officinalis) and Triscelophorus acuminatus (in R. mucronata and in S. caseolaris). Surface-sterilized whole root and root bark segments of R. mucronata sampled from the mid-tide level on direct plating yielded more fungi than that of the root segments sampled from low-tide and high-tide levels. The greatest number of isolates, species richness, and diversity of fungi were shown by the whole root segments of R. mucronata from the mid-tide level. Rarefaction indices also revealed the highest expected number of species out of 150 random isolations from the mid-tide level samples of whole root and root bark segments of R. mucronata. The present study showed that fungi in mangrove roots are composed of a consortium of soil, marine, and freshwater fungi.Key words: mangroves, endophytes, fungi, diversity, India.
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Carey, H. V., X. Y. Tien, L. J. Wallace et H. J. Cooke. « Muscarinic receptor subtypes mediating the mucosal response to neural stimulation of guinea pig ileum ». American Journal of Physiology-Gastrointestinal and Liver Physiology 253, no 3 (1 septembre 1987) : G323—G329. http://dx.doi.org/10.1152/ajpgi.1987.253.3.g323.
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Muscarinic receptors involved in the secretory response evoked by electrical stimulation of submucosal neurons were investigated in muscle-stripped flat sheets of guinea pig ileum set up in flux chambers. Neural stimulation produced a biphasic increase in short-circuit current due to active chloride secretion. Atropine and 4-diphenylacetoxy-N-methylpiperadine methiodide (4-DAMP) (10(-7) M) were more potent inhibitors of the cholinergic phase of the response than was pirenzepine. Dose-dependent increases in base-line short-circuit current were evoked by carbachol and bethanechol; 4-hydroxy-2-butynyl trimethylammonium chloride (McN A343) produced a much smaller effect. Tetrodotoxin abolished the effects of McN A343 but did not alter the responses of carbachol and bethanechol. McN A343 significantly reduced the cholinergic phase of the neurally evoked response and caused a rightward shift of the carbachol dose-response curve. All muscarinic compounds inhibited [3H]quinuclidinyl benzilate binding to membranes from mucosal scrapings, with a rank order of potency of 4-DAMP greater than pirenzepine greater than McN A343 greater than carbachol greater than bethanechol. These results suggest that acetylcholine released from submucosal neurons mediates chloride secretion by interacting with muscarinic cholinergic receptors that display a high binding affinity for 4-DAMP. Activation of neural muscarinic receptors makes a relatively small contribution to the overall secretory response.
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Lélu, Maud, Isabelle Villena, Marie-Laure Dardé, Dominique Aubert, Régine Geers, Emilie Dupuis, Francine Marnef et al. « Quantitative Estimation of the Viability of Toxoplasma gondii Oocysts in Soil ». Applied and Environmental Microbiology 78, no 15 (11 mai 2012) : 5127–32. http://dx.doi.org/10.1128/aem.00246-12.
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ABSTRACTToxoplasma gondiioocysts spread in the environment are an important source of toxoplasmosis for humans and animal species. Although the life expectancy of oocysts has been studied through the infectivity of inoculated soil samples, the survival dynamics of oocysts in the environment are poorly documented. The aim of this study was to quantify oocyst viability in soil over time under two rain conditions. Oocysts were placed in 54 sentinel chambers containing soil and 18 sealed water tubes, all settled in two containers filled with soil. Containers were watered to simulate rain levels of arid and wet climates and kept at stable temperature for 21.5 months. At nine sampling dates during this period, we sampled six chambers and two water tubes. Three methods were used to measure oocyst viability: microscopic counting, quantitative PCR (qPCR), and mouse inoculation. In parallel, oocysts were kept refrigerated during the same period to analyze their detectability over time. Microscopic counting, qPCR, and mouse inoculation all showed decreasing values over time and highly significant differences between the decreases under dry and damp conditions. The proportion of oocysts surviving after 100 days was estimated to be 7.4% (95% confidence interval [95% CI] = 5.1, 10.8) under dry conditions and 43.7% (5% CI = 35.6, 53.5) under damp conditions. The detectability of oocysts by qPCR over time decreased by 0.5 cycle threshold per 100 days. Finally, a strong correlation between qPCR results and the dose infecting 50% of mice was found; thus, qPCR results may be used as an estimate of the infectivity of soil samples.
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Makkar, Sameer, Harpreet Kaur, Anurag Aggarwal et Ruchi Vashisht. « A Confocal Laser Scanning Microscopic Study Evaluating the Sealing Ability of Mineral Trioxide Aggregate, Biodentine and Anew Pulp Capping Agent-Theracal ». Dental Journal of Advance Studies 03, no 01 (avril 2015) : 020–25. http://dx.doi.org/10.1055/s-0038-1672009.
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Abstract Aims and Objectives: Viability and health of the pulpal tissue after an exposure can be stimulated with biocompatible pulp capping materials. Mineral trioxide aggregate(MTA), though biocompatible with excellent sealing ability, has clinical disadvantages like poor handling properties and long setting time. New pulp capping agents- Biodentine and Theracal have proven to overcome MTA’s shortcomings. This study aimed to comparatively evaluate the sealing ability of Mineral Trioxide Aggregate(Angelus), Biodentine (Septodont) and Theracal(Bisco) when used as pulp capping agents. Materials and Methods: Occlusal cavities were prepared in extracted human third molars. The cavities were divided into 3 groups containing 12 samples each. Pulp capping in samples of group I, II and III was done with MTA, Biodentine and Theracal respectively. All samples were kept in a damp environment for 24 hrs. In each tooth, the root was cut just below the cementum-enamel junction. An aqueous 0.25% solution of Rhodamine-B was put in the open pulp chambers of all the samples and placed upside-down in a damp environment. The dye was left for 3 hrs to permeate toward the interface. After being stained, all samples were rinsed with distilled water and sectioned vertically. A Confocal Laser Scanning Microscope was used to image the samples. Results: No significant difference was found in interfacial microleakage between MTA and Biodentine. Theracal exhibited less interfacial microleakage than the two. Conclusion: Biodentine and MTA exhibit an efficient and durable protection of pulp. Theracal exhibits better sealing ability as a pulp capping agent than MTA and Biodentine.
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Levy, Joseph, Andrew Fountain, W. Berry Lyons et Kathy Welch. « Experimental formation of pore fluids in McMurdo Dry Valleys soils ». Antarctic Science 27, no 2 (23 septembre 2014) : 163–71. http://dx.doi.org/10.1017/s0954102014000479.
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AbstractThe aim of the study was to determine if soil salt deliquescence and brine hydration can occur under laboratory conditions using natural McMurdo Dry Valleys soils. The experiment was a laboratory analogue for the formation of isolated patches of hypersaline, damp soil, referred to as ‘wet patches’. Soils were oven dried and then hydrated in one of two humidity chambers: one at 100% relative humidity and the second at 75% relative humidity. Soil hydration is highly variable, and over the course of 20 days of hydration, ranged from increases in water content by mass from 0–16% for 122 soil samples from Taylor Valley. The rate and absolute amount of soil hydration correlates well with the soluble salt content of the soils but not with grain size distribution. This suggests that the formation of bulk pore waters in these soils is a consequence of salt deliquescence and hydration of the brine from atmospheric water vapour.
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Cooke, H. J., Y. Z. Wang, R. Reddix et N. Javed. « Cholinergic and VIP-ergic pathways mediate histamine H2 receptor-induced cyclical secretion in the guinea pig colon ». American Journal of Physiology-Gastrointestinal and Liver Physiology 268, no 3 (1 mars 1995) : G465—G470. http://dx.doi.org/10.1152/ajpgi.1995.268.3.g465.
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Previous studies demonstrated neurally mediated recurrent increases in short-circuit current (Isc) suggestive of anion secretion in guinea pig distal colon. To determine the neural pathways involved, segments of distal colon from guinea pigs were mounted in flux chambers. In muscle-stripped or whole thickness preparations, serosal addition of the histamine H2 receptor agonist, dimaprit, caused cyclical increases in Isc, which were reduced by the chloride channel blocker, N-phenylanthranilic acid, but not by the sodium channel blocker amiloride. Dimaprit stimulated release of [3H]acetylcholine and vasoactive intestinal polypeptide (VIP) from submucosal/mucosal sheets. Dimaprit caused recurrent increases in Isc, which were significantly decreased by mecamylamine, a nicotinic receptor antagonist, and nearly abolished by the muscarinic antagonist, atropine (M3 > M1 = M2). The muscarinic antagonist, 4-diphenylacetoxy-N-methyl-piperidine methiodide (4-DAMP, M3 > M1), was more potent than pirenzepine (M1 > M3) in reducing recurrent increases in Isc. Dimaprit- and electrically evoked secretion were inhibited by the VIP antagonists [4Cl-D-Phe6, Leu17]VIP and VIP hybrid. The results suggest the involvement of VIP-ergic and cholinergic neurons utilizing nicotinic and muscarinic synapses in mediating secretion.
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Blumenthal, Jeffrey A., James J. Onorato et Hannah V. Carey. « Muscarinic inhibition of substance P induced ion secretion in piglet jejunum ». Canadian Journal of Physiology and Pharmacology 76, no 2 (1 février 1998) : 169–75. http://dx.doi.org/10.1139/y98-009.
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We examined the effects of the muscarinic agonist carbachol on ion secretion induced by substance P (SP) in piglet jejunal tissues mounted in Ussing chambers. Tetrodotoxin was present in all solutions to inhibit neural activity. Carbachol added 10 min prior to 0.75 µM SP dose dependently inhibited subsequent SP responses, with 90% inhibition at 10 µM carbachol. Addition of an equipotent dose of SP (7.5 µM) had no effect on subsequent carbachol-induced secretion. Carbachol's inhibition of SP-induced secretion was evident for at least 45 min and was abolished by prior addition of the M3 receptor antagonist 4-diphenylacetoxy-N-methyl-piperidine methiodide (4-DAMP), but remained intact in the presence of the M2 antagonist gallamine or the nicotinic antagonist mecamylamine. Atropine added 10 min after carbachol restored subsequent SP responses toward control levels. Carbachol also reduced secretory responses to histamine and, to a lesser extent, prostaglandin E2 (PGE2). SP-induced secretion was not affected by prior addition of histamine and was reduced by PGE2 only at the highest PGE2 concentration. The results suggest that activation of the epithelial M3 receptor by carbachol inhibits subsequent secretory responses to the calcium-mediated agonists SP and histamine in piglet jejunum. This may reflect muscarinic activation of a negative messenger in epithelial cells that limits Cl- secretion.Key words: substance P, muscarinic receptor, carbachol, desensitization, piglet, jejunum, intestine, ion secretion.
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Mammarella, I., P. Werle, M. Pihlatie, W. Eugster, S. Haapanala, R. Kiese, T. Markkanen, Ü. Rannik et T. Vesala. « A case study of eddy covariance flux of N<sub>2</sub>O measured within forest ecosystems : quality control and flux error analysis ». Biogeosciences 7, no 2 (2 février 2010) : 427–40. http://dx.doi.org/10.5194/bg-7-427-2010.
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Abstract. Eddy covariance (EC) flux measurements of nitrous oxide (N2O) obtained by using a 3-D sonic anemometer and a tunable diode laser gas analyzer for N2O were investigated. Two datasets (Sorø, Denmark and Kalevansuo, Finland) from different measurement campaigns including sub-canopy flux measurements of energy and carbon dioxide are discussed with a focus on selected quality control aspects and flux error analysis. Although fast response trace gas analyzers based on spectroscopic techniques are increasingly used in ecosystem research, their suitability for reliable estimates of EC fluxes is still limited, and some assumptions have to be made for filtering and processing data. The N2O concentration signal was frequently dominated by offset drifts (fringe effect), which can give an artificial extra contribution to the fluxes when the resulting concentration fluctuations are correlated with the fluctuations of the vertical wind velocity. Based on Allan variance analysis of the N2O signal, we found that a recursive running mean filter with a time constant equal to 50 s was suitable to damp the influence of the periodic drift. Although the net N2O fluxes over the whole campaign periods were quite small at both sites (~5 μg N m−2 h−1 for Kalevansuo and ~10 μg N m−2 h−1 for Sorø), the calculated sub-canopy EC fluxes were in good agreement with those estimated by automatic soil chambers. However, EC N2O flux measurements show larger random uncertainty than the sensible heat fluxes, and classification according to statistical significance of single flux values indicates that downward N2O fluxes have larger random error.
Thèses sur le sujet "Damp chambers"
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Zigler, Amy Elizabeth. « Selected chamber works of Dame Ethel Smyth ». [Gainesville, Fla.] : University of Florida, 2009. http://purl.fcla.edu/fcla/etd/UFE0041106.
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Larsson, Peter. « Calibration of Ionization Chambers for Measuring Air Kerma Integrated over Beam Area in Diagnostic Radiology ». Doctoral thesis, Linköpings universitet, Medicinsk radiofysik, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-7848.
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The air kerma area product PKA is an important quantity used by hospital physicists in quality assurance and optimization processes in diagnostic radiology and is recommended by national authorities for setting of diagnostic reference levels. PKA can be measured using a transmission ionization chamber (kerma area product (KAP) meter) mounted on the collimator housing. Its signal QKAP must be calibrated to give values of PKA. The objective of this thesis is to analyze the factors influencing the accuracy of the calibration coefficients k= PKA/QKAP and of reported PKA-values. Due to attenuation and scatter in the KAP-meter and presence of extra-focal radiation, values of PKA depend on the choice of integration area A and the distance of the reference plane from the focal spot yielding values of PKA that may differ by as much as 23% depending on this choice. The two extremes correspond to (1) PKA=PKA,o integrated over the exit surface of the KAP-meter resulting in geometry independent calibration coefficients and (2) PKA=PKA,Anom integrated over the nominal beam area in the patient entrance plane resulting in geometry dependent calibration coefficients. Three calibration methods are analysed. Method 1 aims at determine PKA,Anom, for clinical use at the patient entrance plane. At standard laboratories, the method is used to calibrate with respect to radiation incident on the KAP-meter. Problems with extra-focal and scattered radiation are then avoided resulting in calibration coefficients with low standard uncertainty (±1.5 %, coverage factor 2). Method 2 was designed in this work to approach determination of PKA,o using thermoluminescent detectors to monitor contributions from extra-focal radiation and account for the heel effect. The uncertainty in derived calibration coefficients was ± 3% (coverage factor 2). Method 3 uses a Master KAP-meter calibrated at a standard laboratory for incident radiation to calibrate clinical KAP-meters. It has potential to become the standard method in the future replacing the tedious method 2 for calibrations aiming at determination of PKA,o. Commercially available KAP-meters use conducting layers of indium oxide causing a strong energy dependence of their calibration coefficients. This dependence is investigated using Monte Carlo simulations and measurements. It may introduce substantial uncertainties in reported PKA– values since calibration coefficients as obtained from standard laboratories are often available only at one filtration (2.5 mm Al) as function of tube voltage or HVL. This is not sufficient since higher filtrations are commonly used in practice, including filters of Cu. In extreme cases, calibration coefficients for the same value of HVL but using different tube voltages and filtrations can deviate by as much as 30%. If standardised calibration methods are not used and choice of calibration coefficients not carefully chosen with respect to beam quality, the total uncertainty in reported PKA–values may be as large as 40-45%. Conversion of PKA-values to risk related quantities is briefly discussed. The large energy dependence of the conversion coefficients, ε/PKA, for determination of energy imparted,ε, to the patient reduces to a lower energy dependence of calibration coefficients CQ,ε = ε/QKAP for determination of ε from the KAP-meter signal.
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Casta, Isabelle. « Le corps comme territoire de fiction dans quelques romans de gaston leroux (le mystere de la chambre jaune" , "le parfum de la dame en noir" , "le fantome de l'opera" , "la poupee sanglante" t. 1 et 2) ». Amiens, 1992. http://www.theses.fr/1992AMIE0007.
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Cette these se propose d'etudier, sous trois eclairages, le travail de representation que les romans de gaston leroux organisent autour d'un theme majeur : la fiction des corps, leur description et leur interaction. A travers la rhetorique, l'erotique et l'heuristique, qui marquent les phases successives de notre reflexion, le corps delimite son propre territoire de sens, dont la decouverte redouble le proces policier proprement dit ; du cadavre abandonne a la reparation des blessures, les romans explorent ainsi le monde des espaces phantasmatiques qui emanent de la poetique des corps, dans leur strategies d'evitement ou de seduction reciproque. L'ecriture de l'enigme rejoint l'enigme du corps, a la fois anatomique et onirique, pris dans l'epaisseur des cliches et s'en arrachant par la violence du desir, qu'il soit desir de l'autre ou desir d'histoire. L'interet majeur des romans de notre corpus reside dans la tension. Entre les presupposes de la paralitterature (lisibilite et roublardise) et le traitement baroque des corps, par la metaphore et la contiguite, qui comble les non-dits des recits. Le "mystere" des corps (sacrifies par la bienseance mais triomphants par le trouble qu'ils suscitent), cree l'ecart ou se deploie l'ecriture leroussienne.
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Casta, Isabelle. « Le corps comme territoire de fiction dans quelques romans de Gaston Leroux Le Mystère de la chambre jaune, Le parfum de la dame en noir, Le fantôme de l'opéra, La poupée sanglante, t. 1 et 2. Thèse de doctorat nouveau régime littérature française, Université de Picardie, 1992 / ». Villeneuve d'Ascq : Presses universitaires du Septentrion, 2000. http://catalog.hathitrust.org/api/volumes/oclc/44055163.html.
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Požárová, Miroslava. « Interaktivní výukové modely vodohospodářských staveb pro Hydrotechnickou laboratoř Stavební školy ve Vysokém Mýtě ». Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2016. http://www.nusl.cz/ntk/nusl-240198.
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In 2014 a new Hydro-technical laboratory was built at the High School of Civil Engineering in Vysoké Mýto. The laboratory’s hydraulic circuit is equipped with a reserve line enabling independent standing models of hydro-technical structures to be connected. Two interactive instructional models are designed for this laboratory. The first is a model of a concrete dam. The dam is equipped with one bottom outlet, a hydraulic power plant and an emergency spillway crest gate. The discharge part of the model is equipped with a downflow baffle for regulating the tailwater level and a measuring weir enabling the flow rate to be measured at the discharge point from the model. The total capacity of the model is 10 l/s. The second model is a model of a weir structure. The weir structure consists of a controlled segment sluice gate weir composed of three sections. The model includes a one-nave lock chamber and hydraulic power plant. The tailwater level can also be regulated using a downflow baffle. The total capacity of this model is 20 l/s. The models can be used for teaching the subjects of hydraulics, hydrology and hydro-technical structures. They can be used to demonstrate various hydraulic phenomena and to describe individual functional objects using specialist terminology. This thesis contains the full project documentation for both proposed models, including hydro-technical calculations and text appendices.
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Konvalinková, Tereza. « Interakce mikroskopických hub a krytenek v opadu smrku ztepilého ». Master's thesis, 2011. http://www.nusl.cz/ntk/nusl-297555.
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Both testate amoebae and fungi are common inhabitants of coniferous litter. Their interactions in this environment were rarely studied, although they reach high biodiversity and can play a significant role in nutrient cycling in this environment. In this study, a cultivation of litter needles in the damp chambers was used to investigate interactions between fungi and testate amoebae. Observation of spruce litter needles in environmental scanning electron microscope was used to better characterize testate amoebae communities directly on the needles. Additionally, two experiments changing the biotic conditions in the microcosm were used to follow a principle of the interactions. Three species of testate amoebae from litter needles were able to colonize the filter paper on the bottom of the damp chambers. Occurrence of Phryganella acropodia and Assulina muscorum on the filter paper was significantly fuelled by the presence of mycelium. Assulina muscorum was associated with the fungal spores and Arcella discoides was attracted by sporulating colonies of Cladosporium spp. in the damp chambers. By contrast, no association of putatively mycophagous Phryganella acropodia with fungal spores was observed. Arcella discoides was attracted both by live and death mycelium in additional experiment. Interestingly, the...
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Chang, Chan, et 張. 展. « Implementation of DAP rate Meter Prototype for Transparent Ionization Chamber ». Thesis, 2018. http://ndltd.ncl.edu.tw/handle/h5vbap.
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碩士國立清華大學
電機工程學系所
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The objective of this thesis is to develop a dose area product (DAP) rate meter prototype for transparent ionization chamber to monitor the radiation dose. When X-ray irradiates the ionization chamber, the radiation causes air to ionize, producing electrons which are collected by the charge collection electrode to form the electron flow, the current signal is then converted into a voltage signal through the transimpedance amplifier (TIA). The MSP430F5438 Experimenter Board converts the analog voltage signal into digital form via ADC and then calculates the electron flow, which then mutiplies the pertinent calibration factors to obtain the DAP rate. This thesis uses Altium Designer14 to design a PC board for transimpedance amplifiers, SolidWorks2017 to design the instrument case, and Texas Instruments Code Composer Studio V6 as a program development environment to design programs for controlling the MSP430F5438 experimenter board’s UART and I/O ports, LCD, switches and four major instrument functions, such as parameter setting, current and temperature measurement, data transmission, and button test. The meter can use the switch to select different measurement ranges. When the measurement range is 0.3 nA~40 nA, the measurement error is about 1%; the measurement range is 10pA~700 pA, and the error can be less than 1%. The electron flow collected by the spherical ionization chamber when X-ray is used as the radiation source is measured by our prototype for various X-ray tube voltages: 80kV, 120kV, 150kV, tube currents: 5mA, 10mA, 15mA, 20mA, 25mA, 30mA, and with the high-voltage module of our prototype provides the negative high voltage to the spherical ionization chamber’s electrode plate. Measurements of same X-ray tube voltage and current conditions are also performed by using INER’s measurement instrument (Keithly6517A) and high voltage power supply (Keithly247). The errors between measurement results of our prototype and INER’s instruments are mostly less than 1.5%. The prototype meter is indeed suitable for measuring the weak current of the ionization chamber in real time.
Livres sur le sujet "Damp chambers"
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Chigas, Frank. The damp chamber : And other bad places. San Francisco : Medusa Press, 2004.
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International, Workshop on Dam Fracture and Damage (1994 Chambéry France). Dam fracture and damage : Proceedings of the International Workshop on Dam Fracture and Damage/Chambery/France/16-18 March 1994. Rotterdam, Netherlands ; Brookfield, VT, USA : A.A. Balkema, 1994.
Trouver le texte intégralChapitres de livres sur le sujet "Damp chambers"
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« Paddlefish Management, Propagation, and Conservation in the 21st Century ». Dans Paddlefish Management, Propagation, and Conservation in the 21st Century, sous la direction de MAURICE F. METTEE, PATRICK E. O’NEIL et STEVEN J. RIDER. American Fisheries Society, 2009. http://dx.doi.org/10.47886/9781934874127.ch5.
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<em>Abstract</em>.—This paper describes the movements of 102 sonic tagged paddlefish released in the Alabama River from 2001 to 2005 and 10 sonic fish released in Mobile Bay in 2006, evaluates possible spawning site fidelity at Millers Ferry Lock and Dam, and presents fisheries, river discharge, and lock use data in support of our recommendation to implement January through April fish passage operations at two locks and dams in the Alabama River. Fifty-seven paddlefish released in the Alabama River remained between Millers Ferry and Claiborne locks and dams. Thirty-four fish moved downstream past Claiborne Lock and Dam and inhabited widely separated sites in the Alabama, Tensaw, and Tombigbee rivers. One fish moved upstream through Millers Ferry lock chamber and was detected in Dannelly Reservoir for 2 years. Spawning site fidelity is suggested based on the return of 15 tagged fish to Millers Ferry tailwater area 1 or 2 years following their release. Four of eight paddlefish released in Mobile Bay remained in the Tensaw River system throughout the study. Four other fish were detected above and below Claiborne Lock and Dam in the Alabama River. Movement patterns documented during our study established an important life history link between spawning habitats in the Alabama River, summer feeding habitats in the Mobile–Tensaw River delta, and winter feeding habitats in Mobile Bay. Proposed fish passage operations at Claiborne and Millers Ferry locks and dams should not be expensive to implement and they should not adversely affect navigation, hydroelectric generation schedules, and industrial water needs along the river.
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Fuamba, M., G. Brosseau, E. Mainville, S. Colameo et D. Sparks. « Role and behavior of surge chamber in hydropower : Case of the Robert Bourassa hydroelectric power plant in Quebec, Canada ». Dans Dams and Reservoirs, Societies and Environment in the 21st Century, Two Volume Set, 867–73. CRC Press, 2006. http://dx.doi.org/10.1201/b16818-136.
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Furbish, David Jon. « Turbulent Flows ». Dans Fluid Physics in Geology. Oxford University Press, 1997. http://dx.doi.org/10.1093/oso/9780195077018.003.0018.
Texte intégralRésumé :
Many geological flows involve turbulence, wherein the velocity field involves complex, fluctuating motions superimposed on a mean motion. Flows in natural river channels are virtually always turbulent. Magma flow in dikes and sills, and lava flows, can be turbulent. Atmospheric flows involving eolian transport are turbulent. The complex, convective overturning of fluid in a magma chamber or geyser is a form of turbulence. Thus, a description of the basic qualities of these complex flows is essential for understanding many geological flow phenomena. Turbulent flows generally are associated with large Reynolds numbers. Recall from Chapter 5 that the Reynolds number Re is a measure of the ratio of inertial to viscous forces acting on a fluid element, . . . Re = ρUL/μ . . . . . . (14.1) . . . where the characteristic velocity U and length L are defined in terms of the particular flow system. Thus, turbulence is typically associated, for given fluid density ρ and viscosity μ, with high-speed flows (although we must be careful in applying this generality to thermally driven convective motions; see Chapter 16). A simple, visual illustration of this occurs when smoke rises from a cigar within otherwise calm, surrounding air. The smoke acts as a flow tracer. Smoke molecules at the cigar tip start from rest, since they are initially attached to the cigar. Upward fluid motion, as traced by the smoke, initially is of low speed, and viscous forces have a relatively important influence on its behavior. The flow is laminar; smoke streaklines are smooth and locally parallel. But as the flow accelerates upward, it typically reaches a point where viscous forces are no longer sufficient to damp out destabilizing effects of growing inertial forces, and the flow becomes turbulent, manifest as whirling, swirling fluid motions (see Tolkien [1937]). Throughout this chapter we will consider only incompressible Newtonian fluids. Unfortunately, the complexity of turbulent fluid motions precludes directly using the Navier–Stokes equations to describe them. Instead, we will adopt a procedure whereby the Navier–Stokes equations are recast in terms of temporally averaged or spatially averaged values of velocity and pressure, and fluctuations about these averages.
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Thomson, Peter. « 160° ». Dans Sacred Sea. Oxford University Press, 2007. http://dx.doi.org/10.1093/oso/9780195170511.003.0030.
Texte intégralRésumé :
If you missed the fences and the swath of open land in the woods that mark the border, you can’t help but notice that you’ve finally left Russia because the human presence beyond the windows of the train is no longer disheveled. Finland shares a long history of tension with its huge and powerful neighbor to the east, but I wonder if having to share such a long border with Russia galls the Finns most of all because everything in their country is so orderly, while everything in Russia is such a mess. The immediate difference crossing between these two countries may well be more stark than between any two others on the planet. We are out of Russia and into suddenly more familiar and comforting territory, and James and I are suddenly giddy and joking about everything— about how the damn Finns have a ridiculous word like Hei for hello instead of the far simpler Russian Zdravstvuite, about how the Finns must long for a life without lawn mowers, a social contract, and more than one color of paint, about how surprised we are that the Finns and the European Union allow Russian trains to use their filthy open toilets within their territory but have perhaps granted a special temporary exemption to trains originating in SDCs—shit-dumping countries. . . . Russia recedes beyond the Gulf of Finland, beyond the lovely decompression chamber of Helsinki, beyond the soothingly smooth and comfortable trains and beds of Western Europe and all its polite people who almost always seem to speak English, and with every passing hour and kilometer we are at once more relaxed and more glad to be rid of the place and more and more sorry that we are not still there. Russia grabs hold of you tight, and if it often feels as if it’s choking the life out of you and making you want to flee, its suffocating embrace is also powerfully seductive. If it often seems to be going to extraordinary lengths to make itself infuriating and impenetrable—almost challenging you just to give up on it and turn your attention elsewhere—it also makes it impossible for you to turn away, and ultimately makes the whole exhausting and exhilarating encounter worth it.
Actes de conférences sur le sujet "Damp chambers"
1
Camporeale, S. M., B. Fortunato et M. Mastrovito. « Prediction of Thermoacoustic Instability in Combustion Chamber Equipped With Passive Dampers ». Dans ASME Turbo Expo 2008 : Power for Land, Sea, and Air. ASMEDC, 2008. http://dx.doi.org/10.1115/gt2008-51387.
Texte intégralRésumé :
The thermoacoustic mechanism is considered one of the causes of combustion instability in modern gas turbine combustion chambers, according to the basic mechanism proposed by Rayleigh. On this basis, several authors have proposed the use of acoustic passive dampers, in order to hinder the onset of instability or, at least, to reduce the amplitude of the pressure oscillations. The passive device will produce two main actions, cooperating to stabilize the system: dissipating the acoustic energy produced by thermal fluctuations and modifying the phase between acoustic pressure and heat release in order to reduce the production of acoustic energy. The Helmholtz resonators proposed as damping devices act as acoustic impedances whose characteristics can be modified, not only by means of the manipulation of their geometrical features (volume, length and section of the neck) but also by means of holes and cooling flow. The present paper aims at describing how a resonator connected to the combustion chamber is able not only to damp the pressure oscillation but also to modify the instability conditions and, under certain conditions, to convert an unstable condition in a stable one, in a relatively large operating range. The study has been carried for a cannular type of combustion chamber by means of a one-dimensional analytical model and modelling the Helmholtz resonator by means of the electro-acoustic analogy. Two different flame-acoustic interaction model have been examined. As a result of the application of the model the optimal design characteristics of the resonator and its position within the chamber are obtained. Moreover, unlike what it was expected, it appears that the optimal resonance frequency of the resonator does not exactly meet the frequency of the acoustic mode to be damped.
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Tran, Nicolas, S. Ducruix et T. Schuller. « Passive Control of the Inlet Acoustic Boundary of a Swirled Turbulent Burner ». Dans ASME Turbo Expo 2008 : Power for Land, Sea, and Air. ASMEDC, 2008. http://dx.doi.org/10.1115/gt2008-50425.
Texte intégralRésumé :
The efficiency of perforated panels inserted in the injection line of a swirled turbulent burner is investigated as a passive control solution for combustion instabilities. Perforated panels backed by a cavity are widely used as acoustic liners, mostly in the hot gas region of combustion chambers to reduce pure tone noise levels. This paper focuses on the implementation of this technology in the injection line of a burner. The system is used to control the inlet acoustic reflection coefficient of the burner to stabilize the combustion. This method is shown to be particularly efficient because high acoustic fluxes issued from the combustion region are concentrated on a small surface area in the injection line. Theoretical results are used to design two types of perforated plates featuring similar acoustic damping properties when submitted to low amplitude pressure fluctuations (linear regime). However it is shown that their behavior largely differs when facing large pressure fluctuations levels (non linear regime) typical of those encountered during self-sustained combustion oscillations. Design criteria are given to control the reflection coefficient of perforated panels submitted to high pressure fluctuations levels and damp thermo-acoustic oscillations. While developed on a laboratory scale swirled combustor, this method is more general and could easily be adapted to practical combustors.
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Kennedy, C. E., K. Terwilliger et G. J. Jorgensen. « Analysis of Accelerated Exposure Testing of Thin-Glass Mirror Matrix ». Dans ASME 2005 International Solar Energy Conference. ASMEDC, 2005. http://dx.doi.org/10.1115/isec2005-76040.
Texte intégralRésumé :
Concentrating solar power (CSP) companies have deployed thin-glass mirrors produced by wet silver processes on ∼1-mm-thick, relatively lightweight glass. These mirrors have been bonded to metal substrates in commercial installations. Initial hemispherical reflectance is ∼93% to 96%, and the cost is ∼$16.1/m2 to $43.0/m2. These mirrors have the confidence of the CSP industry. However, corrosion was observed in mirror elements of operational solar systems deployed outdoors for 2 years. NREL’s advanced optical materials team was assigned to investigate the problem. First, it was noted that this corrosion is very similar to the corrosion bands and spots observed on small (45 mm × 67 mm) thin-glass mirrors laminated to metal substrates with several different types of adhesives and subjected to accelerated exposure testing (AET) at NREL. These samples exhibited corrosion at the unprotected edges and along cracks, and the choice of adhesive affected the performance of weathered thin-glass mirrors. Secondly, two significant changes in mirror manufacture have occurred in the wet-chemistry process because of environmental concerns. The first is the method of forming a copper-free reflective mirror, and the second is the use of lead-free paints. A test matrix of 84 combinations of sample constructions (mirror type / back protective paint / adhesive / substrate) was devised for AET as a designed experiment to identify the most promising mirrors, paints, and adhesives for use with concentrator designs. Two types of accelerated exposure were used: an Atlas Ci5000 WeatherOmeter (WOM) and a damp-heat chamber. Based on an analysis of variance (ANOVA), the various factors and interactions were modeled. These samples now have almost 24 months of accelerated exposure. Analysis of the thin-glass mirror matrix indicated that the Glaverbel mirror with a copperless formulation demonstrates slightly better performance compared to the Naugatuck standard copper-containing mirror and new copperless constructions although most results are within experimental uncertainty. Analysis of the thin-glass mirror matrix indicates commercial (non-mirror) back-protective paint applied after mirror manufacturing is not beneficial. Degradation of the samples exposed to date in the damp-heat chamber is similar, but at a rate 10 times faster than observed for samples in the WOM. We will discuss the results of the continued exposure testing of these mirror samples. Although glass mirrors with copper back-layers and heavily leaded paints have been considered robust for outdoor use, the new copperless back-layer and lead-free paint systems were designed for interior mirror applications and the outdoor durability must be determined.
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Van Aken, Bas B., Robert J. Gouwen, Dirk Veldman, Evert Bende et Wilma Eerenstein. « An alternative corrosion resistance test method for solar cells and interconnection materials limiting the number of long-lasting and expensive damp-heat climate chamber tests ». Dans 2013 IEEE 39th Photovoltaic Specialists Conference (PVSC). IEEE, 2013. http://dx.doi.org/10.1109/pvsc.2013.6744252.
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Frati, G., et R. De´nos. « One-Dimensional Unsteady Modeling of the Flow-Field in a Short Duration Facility ». Dans ASME Turbo Expo 2002 : Power for Land, Sea, and Air. ASMEDC, 2002. http://dx.doi.org/10.1115/gt2002-30456.
Texte intégralRésumé :
The establishment of the flow field in the test section of a short duration test rig is a complex process. In order to gain understanding during the transient phase, the time-accurate 1D Euler equations have been solved. The code is validated with two test cases: a steady nozzle flow and an unsteady flow in a shock tube. It is also applied to the short duration facility with an instantaneous opening of the shutter valve. Then, the code is modified to model the progressive opening of the shutter valve using moving boundaries. Finally, pressure and heat losses are also implemented using appropriate additional terms in the momentum and energy equations. The results obtained for the three different cases (instantaneous shutter opening, progressive opening, pressure and heat losses) are compared and discussed. In spite of the simplified approach that is used, the present simulation is able to provide the basic structure and behaviour of the flow field at different locations in the facility. The results show strong transient shock waves that propagate first forward and then backward in the settling chamber and put into evidence oscillations for both pressure and temperature at the test section inlet. In the case of a progressive opening, the process is delayed and the oscillations are smoother. The pressure losses damp significantly the oscillations.
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Zhang, Man. « Large-Eddy Simulation and Linear Acoustic Analysis of a Diffusion Swirling Flame Under Forcing and Self-Excitation ». Dans ASME Turbo Expo 2016 : Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/gt2016-56405.
Texte intégralRésumé :
A diffusion swirling flame under external forcing and self-excitation within a single swirler combustor have been studied in this paper with the large-eddy simulation and linear acoustic method. The combustor features pre-vaporized kerosene as the fuel, a single radial air swirler for flame stabilization and a square cross section chamber with adjustable length. Firstly, self-sustained pressure oscillation has been achieved by using of a chocked nozzle on the chamber outlet with large-eddy simulation. Dynamic pressure oscillations are analyzed in frequency domain through Fast Fourier Transform. The major pressure oscillation is identified as the 1st order longitudinal mode of the chamber. Further, the same frequency in the form of harmonic velocity oscillation is imposed on the inlet of the combustor while the chamber length has been changed. Based on this approach, a comparative study of the flame response with different excitation method but same frequency is carried out. In both self-excited and forced cases, global and local flame responses as well as Rayleigh index have been analyzed and compared. With the flame response function, the excited acoustic modes under the influence of dynamic heat release have been predicted with linear acoustic method and compared with the results obtained from large-eddy simulation. Results show that the flame response presents a great difference in the spacial distribution with different excitation approaches. Thermo-acoustic interaction distributes along the flame front with the expansion of the flame under self-excitation while it damps with the acoustic propagating downstream under forcing condition. As the ratio of flame length to acoustic wave length could not be neglected for the diffusion swirling flame, the global flame response under forcing cannot represent the local response feature of the flame accurately, thus influencing the instability prediction.
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Kim, Kyu Tae, Karthik Kashinath et Simone Hochgreb. « Effects of Nonuniform Reactant Stoichiometry on Combustion Instability ». Dans ASME 2011 Turbo Expo : Turbine Technical Conference and Exposition. ASMEDC, 2011. http://dx.doi.org/10.1115/gt2011-45097.
Texte intégralRésumé :
This paper analyzes the forced response of swirl-stabilized lean-premixed flames to acoustic forcing in a laboratory-scale stratified burner. The double-swirler, double-channel annular burner was specially designed to generate acoustic velocity oscillations and radial fuel stratification at the inlet of the combustion chamber. Temporal oscillations of equivalence ratio along the axial direction are dissipated over a long distance, and therefore the effects of time-varying fuel/air ratio on the flame response are not considered. Simultaneous measurements of inlet velocity and heat release rate oscillations were made using a hot wire anemometer and photomultiplier tubes with narrowband OH*/CH* interference filters. Time-averaged CH* chemiluminescence intensities were measured using an intensified CCD camera. Results show that flame stabilization mechanisms vary depending on stratification ratio for a constant global equivalence ratio. For a uniformly premixed condition, an enveloped M-shaped flame is observed. For stratified conditions, however, a dihedral V-flame and a detached flame are developed for outer stream and inner stream fuel enrichment cases, respectively. Flame transfer function (FTF) measurement results indicate that a V-shaped flame tends to damp incident flow oscillations, while a detached flame acts as a strong amplifier relative to the uniformly premixed condition. The phase difference of FTF increases in the presence of stratification. More importantly, the dynamic characteristics obtained from the forced stratified flame measurements are well correlated with unsteady flame behavior under limit-cycle pressure oscillations. The results presented in this paper provide insight into the impact of nonuniform reactant stoichiometry on combustion instabilities, which has not been well explored to date.
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Li, Hongmin, et Minel J. Braun. « The Sealing Behavior and Force Analysis of a Double-Laminate Single-Padded Finger Seal ». Dans ASME Turbo Expo 2007 : Power for Land, Sea, and Air. ASMEDC, 2007. http://dx.doi.org/10.1115/gt2007-28171.
Texte intégralRésumé :
Finger seals represent a new type of non-contacting seals that allow leakages comparable, or lower than those of the brush seals, while at the same time eliminating the major brush seal drawback: contact and debris production at the shaft/seal interface. This paper presents a numerical investigation of the sealing behavior of a finger seal, which consists of a padded laminate, a padless laminate, and a backplate with a pressure dam. The flow, pressure, and the leakage through a full assembly are obtained by solving the combined full Navier-Stokes and energy equations. Results indicate that the leakage through the pressure chamber varies only with the axial pressure differential. Leakage depends on the axial pressure differential and the finger lifting distance. The lifting force on the pad bottom consists of the hydrodynamic lifting force and the pressure force due to the axial pressure differential. In order for the finger seal to be fully adaptive, the hydrodynamic lifting force has to be dominating over the axial effects.
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Kennedy, C. E., K. Terwilliger et G. J. Jorgensen. « Furthur Analysis of Accelerated Exposure Testing of Thin-Glass Mirror Matrix ». Dans ASME 2007 Energy Sustainability Conference. ASMEDC, 2007. http://dx.doi.org/10.1115/es2007-36182.
Texte intégralRésumé :
Concentrating solar power (CSP) companies have deployed thin-glass mirrors produced by wet-silver processes on ∼1-mm-thick, relatively lightweight glass. These mirrors are bonded to metal substrates in commercial installations and have the confidence of the CSP industry. Initial hemispherical reflectance is ∼93%–96%, and the cost is ∼$16.1/m2–$43.0/m2. However, corrosion was observed in mirror elements of operational solar systems deployed outdoors for 2 years. National Renewable Energy Laboratory (NREL) Advanced Materials Team has been investigating this problem. First, it was noted that this corrosion is very similar to the corrosion bands and spots observed on small (45 mm × 67 mm) thin-glass mirrors laminated to metal substrates with several different types of adhesives and subjected to accelerated exposure testing (AET) at NREL. The corrosion appears as dark splotches in the center of the mirror, with a corresponding 5%–20% loss in reflectivity. Secondly, two significant changes in mirror manufacture have occurred in the wet-chemistry process because of environmental concerns. The first is the method of forming a copper-free reflective mirror, and the second is the use of lead-free paints. However, the copper-free process requires stringent quality control and the lead-free paints were developed for interior applications. A test matrix of 84 combinations of sample constructions (mirror type/back-protective paint/adhesive/substrate) was devised for AET as a designed experiment to identify the most-promising mirrors, paints, and adhesives for use with concentrator designs. Two types of accelerated exposure were used: an Atlas Ci5000 WeatherOmeter (CI5000) and a BlueM damp-heat chamber. Based on an analysis of variance (ANOVA), the various factors and interactions were modeled. These samples now have more than 36 months of accelerated exposure, and most samples have completed their test cycle. We will discuss the results of the final exposure testing of these mirror samples. Glass mirrors with copper back-layers and heavily leaded paints have been considered robust for outdoor use. However, the basic mirror composition of the new mirrors is radically different from that of historically durable solar mirrors, and the outdoor durability must be determined.