Littérature scientifique sur le sujet « DYE DEGRADATION CAPABILITY »
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Articles de revues sur le sujet "DYE DEGRADATION CAPABILITY"
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Singh, Gurpreet, Moolchand Sharma et Rahul Vaish. « Exploring the piezocatalytic dye degradation capability of lithium niobate ». Advanced Powder Technology 31, no 4 (avril 2020) : 1771–75. http://dx.doi.org/10.1016/j.apt.2020.01.031.
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Lin, Ching Hsing, Chen Yu Chang, Yu Jie Chang, Yao Chuan Lee, Mei Yin Hwa et Yu Sen Chang. « Photosensitization of Dye/TiO2 Thin Films by Using Natural Dye of TCPP ». Advanced Materials Research 123-125 (août 2010) : 923–26. http://dx.doi.org/10.4028/www.scientific.net/amr.123-125.923.
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The Dye-Sensitized TiO2 thin film fabricated by TiO2 nanoparticles is a novel technology with advantage in low cost, little pollution and simple in manufacturing process. The fiber-shaped reacting sites provide enlarged photo-sensing area of the TiO2 thin films. Natural dye of TCPP was applied to improve the photo absorbability in this study. Besides, a novel plasma surface activation technique employed on the thin film showed well performance compared with previous reports by heating methods. The SEM images demonstrate that the nano-TiO2 composites deposited on the fiber substrate. Degradation of acetone under 365 and 420 nm light irradiation were conducted to evaluate the photocatalytic ability of the TiO2 and TCPP/TiO2 thin films. While TiO2 thin films gel catalyst showed good photocatalytic performance with a high degradation efficiency of 99.9%, only about 80% conversion efficiency was achieved by the TCPP/TiO2 thin films reactor under 365 nm light irradiation. Although the TCPP dye on TiO2 nanoparticle shows beneficial reflection intensity in 420 nm, the acetone degradation capability of TiO2 and TCPP/ TiO2 thin films reactor decreased about 30% and 25% respectively compared with the degradation efficiency under 365 nm.
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Zissi, U., et G. Lyberatos. « Axo-dye biodegradation under anoxic conditions ». Water Science and Technology 34, no 5-6 (1 septembre 1996) : 495–500. http://dx.doi.org/10.2166/wst.1996.0588.
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Biological oxidation of azo-dyes is important for wastewater treatment. Azo-dyes are synthetic organic colorants that exhibit great structural variety. A large majority of these dyes are released into the environment. The textile industry and dyestuff manufacturing industry are two major sources of released azodyes. In the present study, we focus on the anoxic degradation of a disperse azo-dye, p-aminoazobenzene (pAAB), a simple azo-dye, by a pure culture of Bacillus subtilis, growing on a synthetic medium. Bacillus subtilis is a bacterium capable of using nitrate and/or nitrite as terminal electron acceptor under anoxic conditions. This bacterium lacks the capability for fermentation. The degradation of p-aminoazobenzene by Bacillus subtilis was examined through batch experiments in order to elucidate the mechanism of dye degradation. The results proved that Bacillus subtilis co-metabolizes p-aminoazobenzene under denitrifying conditions, in the presence of glucose as carbon source, producing aniline and p-phenylenediamine as the nitrogen-nitrogen double bond is broken.
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Ain, Qurat Ul, Usman Rasheed, Muhammad Yaseen, Hanbing Zhang et Zhangfa Tong. « Superior dye degradation and adsorption capability of polydopamine modified Fe3O4-pillared bentonite composite ». Journal of Hazardous Materials 397 (octobre 2020) : 122758. http://dx.doi.org/10.1016/j.jhazmat.2020.122758.
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Hsiao, Po-Hsuan, Sasimontra Timjan, Kuan-Yi Kuo, Joon-Ching Juan et Chia-Yun Chen. « Optical Management of CQD/AgNP@SiNW Arrays with Highly Efficient Capability of Dye Degradation ». Catalysts 11, no 3 (22 mars 2021) : 399. http://dx.doi.org/10.3390/catal11030399.
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The facile synthetic method for the preparation of incorporated carbon quantum dots (CQDs)/Ag nanoparticles (AgNPs) with well-aligned silicon nanowire (SiNW) arrays is demonstrated, offering the superior photodegradation capabilities covering UV to visible wavelength regions. By examining the morphology, microstructure, crystallinity, chemical feature, surface groups, light-emitting, and reflection characteristics, these hybrid heterostructures are systematically identified. Moreover, the involving degradation kinetics, band diagram, cycling capability, and underlying mechanism of photodegradation are investigated, validating their remarkable and reliable photocatalytic performances contributed from the strongly reduced light reflectivity, superior capability of charge separation, and sound wettability with dye solutions.
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Amarasinghe, Achala, et Dakshika Wanniarachchi. « Eco-Friendly Photocatalyst Derived from Egg Shell Waste for Dye Degradation ». Journal of Chemistry 2019 (26 septembre 2019) : 1–13. http://dx.doi.org/10.1155/2019/8184732.
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This study is focused on removal of dyes in water bodies using calcined egg shell powder obtained from waste egg shells as a new material for photocatalytic dye removal. The photocatalytic activity of calcined egg shell powder (CESP) was compared with the raw egg shell powder (RESP) under light and dark conditions. The results reveal that CESP has significantly a higher dye degradation capability of 80% compared to the RESP which is 20% under the same condition. Furthermore, under light conditions, CESP has shown nearly 50% increase in dye degradation compared to the same material in the dark. The kinetics of dye degradation follows pseudo-second-order kinetics suggesting the chemisorption process and the Freundlich adsorption isotherm is best fitted (R2 value is 0.96 for the linear fit) with the dye adsorption process. The application of CESP in industry is studied with a textile acid dye Lanasyn Rez F5B, and the results reveal it follows pseudo-second-order kinetics in dye removal.
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Pius, Minu, Frincy Francis et Santhi Joseph. « Enhanced Thermal Diffusivity and Photocatalytic Dye Degradation Capability of Zinc Ferrite/Silver/Silver Chloride Nanocomposites ». Journal of Nano Research 78 (17 avril 2023) : 59–72. http://dx.doi.org/10.4028/p-383q35.
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Herein, we report for the first time the thermal diffusivity of zinc ferrite/ silver/ silver chloride nanocomposite with a four-fold enhancement in comparison with the base fluid. A systematic analysis of the dependence of calcination temperature and synthesis routes on the crystallinity of nanocomposites of zinc ferrite with silver and silver chloride suiting it for diverse applications was done. Synthesized via the co-precipitation method, the samples were characterized using X-ray diffraction, Field emission scanning electron microscopy, Energy dispersive X-ray, Vibration sample magnetometer, ultraviolet-visible Diffusive Reflective spectroscopy and Photoluminescence studies. A zeta potential of -31.1mV was obtained for the sample showing good colloidal stability. The thermal diffusivity of the samples as nanofluids was analyzed using the dual beam thermal lens method. The study also envisages the magnetically retrievable and visible light-active nature of the synthesized samples indicating their suitability for photocatalytic degradation of toxic dyes. The work on photocatalytic degradation of methylene blue stands out in attaining rapid, efficient dye degradation of 98% within 90 minutes of sunlight exposure in comparison with unblended zinc ferrite nanoparticles even without any oxidizing agent.
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Chen, Shuang-Qin, Yang Shao, Meng-Ting Cheng et Ke-Fu Yao. « Effect of residual stress on azo dye degradation capability of Fe-based metallic glass ». Journal of Non-Crystalline Solids 473 (octobre 2017) : 74–78. http://dx.doi.org/10.1016/j.jnoncrysol.2017.07.030.
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Vinayagam, Ramesh, Raja Selvaraj, Pugazhendhi Arivalagan et Thivaharan Varadavenkatesan. « Synthesis, characterization and photocatalytic dye degradation capability of Calliandra haematocephala-mediated zinc oxide nanoflowers ». Journal of Photochemistry and Photobiology B : Biology 203 (janvier 2020) : 111760. http://dx.doi.org/10.1016/j.jphotobiol.2019.111760.
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Miao, Fang, Qianqian Wang, Siyi Di, Lu Yun, Jing Zhou et Baolong Shen. « Enhanced dye degradation capability and reusability of Fe-based amorphous ribbons by surface activation ». Journal of Materials Science & ; Technology 53 (septembre 2020) : 163–73. http://dx.doi.org/10.1016/j.jmst.2020.02.075.
Texte intégralThèses sur le sujet "DYE DEGRADATION CAPABILITY"
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Ford, Colleen D. « The fate of nitrogen in lactose-depleted dairy factory effluent irrigated onto land ». Lincoln University, 2008. http://hdl.handle.net/10182/837.
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A two-year lysimeter study was undertaken to compare the environmental effects (e.g. nitrate leaching and nitrous oxide emissions) of soil applied lactose-depleted dairy factory effluent (LD-DFE) with lactose-rich DFE. The aim of this experiment was to determine the fate of nitrogen from LD-DFE and dairy cow urine applied to a Templeton fine sandy loam soil (Udic Ustrochrept), supporting a herbage cover of ryegrass (Lolium perenne) and white clover (Trifolium repens). Measurements were carried out on the amount of nitrogen lost from the soil via leaching, lost by denitrification, removed by the pasture plants, and immobilized within the soil organic fraction. Further, a comparison between the fate of nitrogen in LD-DFE irrigated onto land under a "cut and carry" system, as opposed to a "grazed" pasture system was undertaken. Lactose-depleted dairy factory effluent was applied at three-weekly intervals during the summer months at rates of 25 and 50 mm, until nitrogen loading targets of 300 and 600 kg N ha⁻¹ yr⁻¹ had been achieved. Measured leaching losses of nitrogen averaged 2 and 7 kg N ha⁻¹ yr⁻¹ for Control 25 and Control 50 treatments; 21, 20 and 58 kg N ha⁻¹ yr⁻¹ for 25 and 50 mm "cut and carry" treatments respectively; and 96 kg N ha⁻¹ yr⁻¹ for the 25 mm "grazed" treatment. The range of nitrate-N leaching loss from LD-DFE plus urine is no different from the lactose-rich DFE nitrate leaching loss. Uptake of nitrogen by the growing pasture averaged 153, 184,340,352,483, and 415 kg N ha⁻¹ yr⁻¹ for Control 25, Control 50, LD-DFE 25 and LD-DFE 50 mm "cut and carry" treatments, and the LD-DFE 25 mm "grazed" treatment, respectively. Denitrification losses were 0.06, 4.4, 1.69, 19.70, and 7.4 kg N ha⁻¹ yr⁻¹ for Control 25, the LD-DFE 25 "cut and carry" treatments, the LD-DFE 25 mm "grazed" treatment, and calculated "paddock losses", respectively. Isotopic nitrogen studies found that 29.4 and 25.8% of applied LD-DFE nitrogen was immobilised in the LD-DFE 25 and LD-DFE 50 "cut and carry" treatments. The results of this experiment confirm the findings of the previous lactose-rich DFE study, in that the effects of grazing stock are of greater environmental concern than the removal of lactose from the effluent waste stream.
Chapitres de livres sur le sujet "DYE DEGRADATION CAPABILITY"
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Al-Awadhi, Jasem Mohammed, Abd el-aziz Khairy Abd el-aal, Raafat Misak et Ahmed Abdulhadi. « Geo- and Environmental Hazard Studies in Kuwait ». Dans The Geology of Kuwait, 171–98. Cham : Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-031-16727-0_8.
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AbstractLow magnitude Earthquakes are the most natural hazard facing Kuwait, while other environmental challenges such as flooding, dust fallout, land degradation, and aeolian sand movement often arise from human impact as well as natural factors. Because of the rapid socio-economic development in the last five decades in Kuwait, these issues cause environmental and social problems as well as economic disturbance; they are also considered natural disasters for country. The scale and intensity of the geological environment hazards are considerably increasing especially land degradation, and impacting on the harsh structure of desert ecosystem. Due to fragility of the desert environment, human activities exceeding the carrying capability of the geo-environment system can easily lead to geological and environmental hazards; such as runoff, sand and dunes movements and dust fallout causing serial environmental and health impacts. Geographic Information System (GIS) has been used to evaluate the degrees of geological hazard and risk by producing maps for each hazard; seismic, sand potentiality, hydrologic risk, land degradation, and sand drift severity maps are produced.
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Malik, Sumira, Shilpa Prasad, Shreya Ghoshal, Shashank Shekhar, Tanvi Kumari, Ankita Agrawal et Bijaya Samal. « Potential of Thallophytes in Degradation of Dyes ». Dans Advances in Environmental Engineering and Green Technologies, 440–74. IGI Global, 2021. http://dx.doi.org/10.4018/978-1-7998-7062-3.ch017.
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Synthetic dyes cause hazardous health-related problems in humans and affect the biological system underwater. They also have a negative impact on the nutritive value of soils and thereby on crops. Until now there is no effective method to remove the harmful component of dyes from the environment. However, the integrated treatment using bio agents with implication of physical and chemical processes can be effective in the treatment of dye effluents. From the complex azo dyes to their dissociation via thallophytes is a new scope for sustenance. Various studies have supported that laccases have the capability to degrade synthetic dyes that have different chemical structures. Thallophytes have been used to degrade the complex dyes with varying ranges of temperature and pH. Thallophytes have recently been used to treat the textile effluents with effective higher temperature and alkaline pH with decreasing BOD and thus cleaning them from environment in an eco-friendly and cost-efficient manner.
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Meghwal, Kiran, Srishti Kumawat, Chetna Ameta et Nirmala Kumari Jangid. « Effect of Dyes on Water Chemistry, Soil Quality, and Biological Properties of Water ». Dans Impact of Textile Dyes on Public Health and the Environment, 90–114. IGI Global, 2020. http://dx.doi.org/10.4018/978-1-7998-0311-9.ch005.
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As the textile industries use aqueous method for dyeing processes, the color that is released in the environment is associated with the incomplete absorption of dyes on fibres. So, there is a strong need to reduce the amount of residual dye in textile effluent. Large amounts of liquid wastes are produced from textile industries that contain both organic and inorganic compounds. The degradation of azo dyes is difficult using the conventional processes. These complex azo dyes containing N=N bond have been found to show carcinogenic evidences on reductive cleavage. Azo dyes have capability to alter physical and chemical properties of soil, causing harm to the water bodies. Dyes are toxic in nature, which is lethal for microorganisms present in soil affecting agricultural productivity. The presence of azo dyes in water decreases its water transparency and water gas solubility. This reduces light penetration through water, decreases its photosynthesis activity, causing oxygen deficiency and de-regulating the biological cycles of aquatic system.
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Nazir, Yusuf, Pranesha Prabakaran, Tahira Naz, Hassan Mohamed, Shaista Nosheen, Abu Bakr Ahmad Fazili, Aidil Abdul Hamid et Yuanda Song. « Acylglycerols in Fungi ». Dans Fungal Lipid Biochemistry, 106–22. BENTHAM SCIENCE PUBLISHERS, 2023. http://dx.doi.org/10.2174/9789815123012123010008.
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Over the past decades, fungi have been increasingly recognized as the potential source of lipids that can be applied in various sectors, including nutraceutical and biofuel. Thus, many studies have been conducted to understand the structural and functional roles of lipid molecules, particularly in the potential oleaginous strains. Lipids produced by oleaginous fungi comprise different classes, and acylglycerol, which are esters formed from different fatty acids and alcohols such as glycerol, represent the major components of the lipid. The biosynthesis of acylglycerol in fungi involved a series of reactions involving the central carbon and glycerol-3-phosphate (G-3-P), while its catabolism in vivo generally involved the degradation of triacylglycerol (TAG) by intracellular lipase resulting in the release of fatty acids and glycerol. The resulting glycerol will be phosphorylated, oxygenated, and enter glycolysis, whereas the fatty acids will undergo β-oxidation into acetyl-CoA and be used for various physiological functions. On the other hand, several fungi species, particularly from the Mucoralles sp, have been documented to be able to utilize the oil and fat as the alternative substrate for growth and reproduction due to its capability to produce extracellular lipases which hydrolyze the ester bond of the TAG. This chapter will comprehensively discuss the functional role of acylglycerol in fungi, its biosynthesis, as well as in vivo and ex vivo degradation in fungi, which will be a bridge toward the development of the industrial application.
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Ahmed, Mohamed M., Arnaud Trouvé, Jason M. Forthofer et Mark A. Finney. « Large eddy simulations of the structure of spreading line fires at flame scale ». Dans Advances in Forest Fire Research 2022, 283–88. Imprensa da Universidade de Coimbra, 2022. http://dx.doi.org/10.14195/978-989-26-2298-9_44.
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Our general objective in the present study is to develop tools to better describe the coupling between solid phase and gas phase processes that control the dynamics of flame spread in wildland fire problems. We focus on a modelling approach that resolves processes occurring at flame scales, i.e., the formation of flammable vapors from the biomass vegetation due to pyrolysis, the subsequent combustion of these fuel vapors with ambient air, the establishment of a turbulent flow because of heat release and buoyant acceleration, and the thermal feedback to the solid biomass through radiative and convective heat transfer. The modelling capability is based on a general-purpose Computational Fluid Dynamics (CFD) library called OpenFOAM and an in-house Lagrangian particle model that treats drying, thermal pyrolysis, oxidative pyrolysis and char oxidation using a one-dimensional porous medium formulation that allows descriptions of thermal degradation processes occurring during both flaming and smoldering combustion. The modelling capability is calibrated for pine wood and is first applied to simulations of fire spread across a surrogate vegetation bed corresponding to thin, monodisperse, cylindrical-shaped sticks of pine wood with prescribed particle and environmental properties (i.e., bed height, surface-to-volume ratio, packing ratio, moisture content, and wind velocity). While the model can be used in sloped terrain, the present simulations are limited to a flat ground surface. The current emphasis is on determining threshold conditions for successful spread, differences between the plume-dominated and wind-driven flame regimes, possible transitions to a steady or time-dependent flame structure, and differences in the relative weights of the flaming and smoldering regions.
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Yeophantong, Pichamon, et Evelyn Goh. « China as a ‘Partial’ Environmental Great Power ». Dans Great Powers, Climate Change, and Global Environmental Responsibilities, 70–94. Oxford University Press, 2022. http://dx.doi.org/10.1093/oso/9780198866022.003.0004.
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How do we recognize an ‘environmental great power’ when we see one? How do great powers wield ‘positive’ and ‘negative’ power in the contested realm of global environmental governance against the background of ever deeper pluralism in international society? This chapter analyses how and to what extent China defines and acts on its environmental responsibilities as a great power and examines its record in two prominent issue-areas: global climate change and the ‘greening’ of the Belt and Road Initiative (BRI) with a focus on its renewable energy projects. While China may appear to be an obvious environmental great power due to its capability to cause environmental harm or provide environmental goods, we argue instead that China is a partial environmental great power. That is, while China’s ‘negative’ or structural power in the global, regional, and national environmental realms is stark and clear, its ‘positive’ power or potential to act in favour of environmental responsibility is less obvious and as yet indeterminate. This is due to China’s ‘identity paradox’—it is both a great power and a developing country; and Chinese actors are at once major perpetrators as well as significant victims of environmental degradation. Hence, China’s record of promoting environmental protection and governance is chequered because its decision makers must constantly balance between multiple constituencies and interests that impinge on how China adopts and acts on its environmental responsibilities both at home and abroad.
Actes de conférences sur le sujet "DYE DEGRADATION CAPABILITY"
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Yang, Weichun, Hang Gao, Songtian Li, Yongsheng Yan, Pengwei Huo et Weiwei Yao. « Preparation of Floatable Compound Photocatalyst of Phosphotungstic Acid/Titanium Dioxide/Float Pearls and Its Degradation Capability to Wastewater of Dye ». Dans 2008 2nd International Conference on Bioinformatics and Biomedical Engineering. IEEE, 2008. http://dx.doi.org/10.1109/icbbe.2008.1055.
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Jin, John C., Tom Viglasky et Andrei Blahoianu. « Canadian Nuclear Regulatory Perspective on Degradation of CANDU Feeder Piping ». Dans ASME 2005 Pressure Vessels and Piping Conference. ASMEDC, 2005. http://dx.doi.org/10.1115/pvp2005-71378.
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As some CANDU plants in Canada are approaching the end of their design lives, various degradation mechanisms which were not anticipated during the design phase have been identified in the CANDU feeder piping and resulted in either actual structural failures or the early replacement of components. In particular, inter-granular stress corrosion cracking (IGSCC) and pipe wall thinning due to flow accelerated corrosion (FAC) are the most prominent degradation mechanisms in the CANDU feeder piping. The Canadian CANDU industry has developed and implemented programs to monitor and manage those unanticipated service-related degradations. Fitness for service guidelines are also developed to justify the structural integrity of the components until the next inspection. These programs include augmented periodic inspections that are targeted to specific components, thereby ensuring the early detection of cracks or excessive wall thinning. The inspection scope and frequency adopted in the degradation management programs exceed the requirements of ASME Section XI, “Inservice Inspection of Nuclear Reactor Coolant Systems” and CSA N285.4, “Periodic Inspection of CANDU Nuclear Power Plants Components”. However, those currently effective codes and standards do not specify requirements which are developed based on the consideration of the specific degradation mechanisms such as IGSCC and FAC wall thinning. Accordingly, it has been an issue for the nuclear regulator as well as in the industry to develop criteria for inspection and replacement/repair, which are based on the current level of understanding of degradation mechanisms and the inspection capability. Presented in this paper are the Canadian regulator’s perspective on the assurance of the safe operation of the CANDU feeder piping which endures degradations of IGSCC and FAC.
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Karli, Geoffrey, Robert McKillip, Sihong Yan et Jose Palacios. « Drag Performance Degradation Due to Icing of eVTOL (Paper 1202) ». Dans Vertical Flight Society 78th Annual Forum & Technology Display. The Vertical Flight Society, 2022. http://dx.doi.org/10.4050/f-0078-2022-17533.
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An empirical model was developed to estimate the liquid water content (LWC) and mean volume diameter (MVD) of super-cooled water droplets of an icing cloud based on the torque variation of a single rotor. The model was developed for eVTOL configurations that can actively monitor on-board torque via an electric speed controller (ESC). Experimental data was collected in the Penn State Adverse Environment Rotor Test Stand chamber under various icing conditions. From experimental data, a relationship between torque degradation and LWC was developed. This LWCis coupled to the FAR Appendix C Icing Envelopes to determine an MVD range of possible values. The range discrepancy is resolved by running Blade Element Momentum Theory (BEMT) and the Han-Palacios Correlation (HPC) for a given set of condition and finding the results that best match with the recorded torque. This process is repeated over the flying duration, using the actively incoming torque information from the ESC. Through the coupling of BEMT and HPC, torque degradation due to blade icing can be modeled and predicted. Being able to predict torque degradation means that the time until a critical torque is reached can also be estimated. This estimated time is then relayed to the vehicle as the available flying time in the current cloud environment. The proposed model was verified by comparing experimental data to the predicted values. The BEMT prediction deviated from the constant measured torque value by 6.0%. For HPC verification, 11 experimental cases were compared to estimated results. On average HPC deviated from the experimental cases by 14.8% at 20 MVD and 16.6% at 40 MVD. With the model verified, a blind study was performed using this method. A case that emulates possible flying conditions in a realistic environment was chosen. Torque data was acquired during the icing event. Within 90 seconds of data available during testing, the MVD and LWC were predicted within 1.39% and 20% respectively. Every 10 seconds the prediction for 10 more seconds into the future was compared to the 'blind' experimental data. On average, the prediction overestimated the torque by 6.5%. Based on the final calculations it was determined that 5.25 minutes of flying time was available to this particular rotor operating within this cloud environment. The presented effort introduces and verifies the capability to determine icing cloud conditions and available flight time available based on the proposed approach.
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Zander, Andre´, et Helmut Nopper. « The COMSY : Code for the Detecting of Piping Degradation Due to Flow-Accelerated Corrosion ». Dans ASME 2008 Pressure Vessels and Piping Conference. ASMEDC, 2008. http://dx.doi.org/10.1115/pvp2008-61823.
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For the aging and plant life management the integrity of the mechanical component and structure is one of the key objectives. In most cases, only a small percentage of mechanical components are subject to significant degradation, e.g. flow-accelerated corrosion which may affect this integrity or the function of the component. Flow-accelerated corrosion (FAC) is a degradation process resulting in wall thinning of piping, vessels, heat exchanger and further equipment made of carbon and low alloy steel. The FAC degradation mechanism occurs only locally under specific condition of flow, water chemistry, temperature and materials applied. The establishment and implementation of a long term strategy is essential to the success of a plant’s FAC program. Effective measures to reduce FAC effects are e.g.: • Optimizing the water chemical treatment (e.g. high-AVT); • Apply improved material concepts for replaced components or lines and/or sufficient wall thickness margins; • Apply qualified repair technologies (e.g. METCO spraying, sheet metal cladding). In case of changes in system operation conditions (e.g. power uprate) the effect on FAC degradation rates should be analyzed before implementation and appropriate precautions should be initiated. For this purpose AREVA NP GmbH has developed the computer code COMSY, which utilities more than 30 years of experience resulting from operational experience and research activities. The COMSY code provides the capability to establish a program guided technical documentation by utilizing a virtual plant model which includes information regarding thermal hydraulic operation, water chemical conditions and materials applied for mechanical components. It provides the option to perform a plant-wide screening for identifying system areas, which are sensitive for degradation mechanisms like FAC. If a system area is identified as being susceptible to degradation, a detailed analysis function enables the condition-oriented service life evaluation of vessels and piping systems in order to localize and conservatively quantify the effect of degradation. Based on these forecasts with COMSY, specific strategies can be developed to mitigate the effect of degradation and inspection activities can be focused on degradation sensitive areas.
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Diab, Aya, Moataz Alaa, Ahmed Hossam El-Din, Hassan Salem et Zakaria Ghoneim. « Performance Degradation of Wind Turbine Airfoils due to Dust Contamination : A Comparative Numerical Study ». Dans ASME Turbo Expo 2015 : Turbine Technical Conference and Exposition. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/gt2015-44012.
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Sand accumulation can pose significant problems to wind turbines operating in the dusty Saharan environments of the Middle East and North Africa. Despite its difficulty, sand particles can be to a great extent avoided using sealed power drive trains; however, surface contamination of the blades is certainly unavoidable. As a result, aerodynamic losses and even premature separation can be incurred. To mitigate such advert consequences and avoid significant power losses, the choice of properly designed airfoil sections with low contamination sensitivity is a must. Alternatively, mitigation techniques for premature separation may also be considered. In this paper the contamination sensitivity of a number of airfoil sections widely used in the wind turbine industry is compared. Additionally, the possibility of deploying a leading edge slat to mitigate the contamination-driven performance degradation of wind turbine airfoils is explored. A two dimensional CFD model of the particle laden flow over an airfoil section is developed by solving Navier-Stokes equations along with the SST k-ω turbulence model. Additionally, a particle deposition model has been deployed via FLUENT’s discrete phase modeling capability to simulate dust particles trajectories and hence predict their accumulation rate. The preliminary results obtained indicate that airfoil sections with low surface contamination sensitivity specifically designed for wind turbines perform better under dusty conditions. Furthermore installing a leading edge slat affects the aerodynamics of the particle laden flow and may therefore be used to mitigate the adverse effects of surface contamination that otherwise would require frequent cleaning which can be expensive.
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Zhou, Qixin, et Yechun Wang. « Flow Accelerated Degradation of Corrosion Protective Organic Coatings ». Dans ASME 2013 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/imece2013-63727.
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Water percolation into coating-metal interface is usually the main cause for the deterioration of corrosion protective property of organic coatings, which leads to coating delamination and under film corrosion. Recently, flowing fluid has received attention due to its capability to accelerate the degradation of materials. A plethora of works have focused on the corrosion of metallic materials accelerated by the flow of working fluids, while few studies have investigated the flow accelerated degrading behavior of organic coatings. For organic coatings, flowing fluid above the coating surface affects corrosion by enhancing the water percolation and by abrading the surface due to wall shear stress. Hence, it is of great importance to understand the influence of flowing fluids on the degradation of corrosion protective organic coatings. In this study, a commercially available epoxy based clear coating and pigmented marine coating were exposed to the laminar flow as well as stationary immersion. The laminar flow was pressure driven and confined in a newly designed flow channel. A 3.5 wt% sodium chloride solution was employed as the working fluid with a variety of flow rates. The corrosion protective properties of organic coatings were monitored inline by Electrochemical Impedance Spectroscopy (EIS) measurement. Equivalent circuit models were employed to interpret the EIS spectra. The time evolution of coating resistance and capacitance obtained from the model was studied to demonstrate the coating degradation. Thickness, gloss, and other topography characterizations were conducted to facilitate the assessment of the corrosion. The immersing solutions were measured by pH and conductivity meters as well as Fourier Transform Infrared Spectrometer (FTIR) to trace coating degradation products as they leached out from the coating. Initial attempts to acquire acceleration factors and predict service lifetime of organic coatings were also conducted.
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Witz, Gregoire, Markus Schaudinn, Joerg Sopka et Tobias Buecklers. « Development of Advanced Thermal Barrier Coatings With Improved Temperature Capability ». Dans ASME Turbo Expo 2016 : Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/gt2016-57425.
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Continuously increasing hot gas temperatures in heavy duty gas turbines lead to increased thermal loadings of the hot gas path materials. Thermal barrier coatings are used to reduce the superalloys temperature and cooling air needs. Until now 6–8 wt% yttria stabilized zirconia is the first choice material for such coatings, but it is slowly reaching its maximum temperature capability due to the phase transformation at high temperature and sintering. New thermal barrier coating material with increased temperature capability enable the next generation of gas turbine with >60% combined cycle efficiency. Such material solutions have been developed through a multi-stage selection process. In a first steps, critical material performance requirements for thermal barrier coating performance have been defined based on the understanding of standard TBC degradation mechanisms. Based on these requirements, more than 30 materials were a pre-selected and evaluated as potential coating materials. After carefully reviewing their properties both from literature data and laboratory test results on raw materials, five materials were selected for coating manufacturing and laboratory testing. Based on the coating manufacturing trials and laboratory test results, two materials have been selected for engine testing, in a first step in GT26 Birr Test Power Plant and afterwards in customer engines. For such tests the original coating thickness has been increased such to achieve coating surface temperature ∼100K higher than with a standard thermal barrier coating. Both coatings performed as predicted in both GT26 Birr Test Power Plant and customer engines.
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Zaccaria, Valentina, Alberto Traverso et David Tucker. « A Real-Time Degradation Model for Hardware in the Loop Simulation of Fuel Cell Gas Turbine Hybrid Systems ». Dans ASME Turbo Expo 2015 : Turbine Technical Conference and Exposition. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/gt2015-43604.
Texte intégralRésumé :
The theoretical efficiencies of gas turbine fuel cell hybrid systems make them an ideal technology for the future. Hybrid systems focus on maximizing the utilization of existing energy technologies by combining them. However, one pervasive limitation that prevents the commercialization of such systems is the relatively short lifetime of fuel cells, which is due in part to several degradation mechanisms. In order to improve the lifetime of hybrid systems and to examine long-term stability, a study was conducted to analyze the effects of electrochemical degradation in a solid oxide fuel cell (SOFC) model. The SOFC model was developed for hardware-in-the-loop simulation with the constraint of real-time operation for coupling with turbomachinery and other system components. To minimize the computational burden, algebraic functions were fit to empirical relationships between degradation and key process variables: current density, fuel utilization, and temperature. Previous simulations showed that the coupling of gas turbines and SOFCs could reduce the impact of degradation as a result of lower fuel utilization and more flexible current demands. To improve the analytical capability of the model, degradation was incorporated on a distributed basis to identify localized effects and more accurately assess potential failure mechanisms. For syngas fueled systems, the results showed that current density shifted to underutilized sections of the fuel cell as degradation progressed. Over-all, the time to failure was increased, but the temperature difference along cell was increased to unacceptable levels, which could not be determined from the previous approach.
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Wu, Shuang, Jingyu Zhao et Guangjian Tian. « Understanding and Mitigating Data Contamination in Deep Anomaly Detection : A Kernel-based Approach ». Dans Thirty-First International Joint Conference on Artificial Intelligence {IJCAI-22}. California : International Joint Conferences on Artificial Intelligence Organization, 2022. http://dx.doi.org/10.24963/ijcai.2022/322.
Texte intégralRésumé :
Deep anomaly detection has become popular for its capability of handling complex data. However, training a deep detector is fragile to data contamination due to overfitting. In this work, we study the performance of the anomaly detectors under data contamination and construct a data-efficient countermeasure against data contamination. We show that training a deep anomaly detector induces an implicit kernel machine. We then derive an information-theoretic bound of performance degradation with respect to the data contamination ratio. To mitigate the degradation, we propose a contradicting training approach. Apart from learning normality on the contaminated dataset, our approach discourages learning an additional small auxiliary dataset of labeled anomalies. Our approach is much more affordable than constructing a completely clean training dataset. Experiments on public datasets show that our approach significantly improves anomaly detection in the presence of contamination and outperforms some recently proposed detectors.
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Serena, Alberto, et Lars E. Bakken. « Experimental Study of the Influence of the Operating Parameters on the Performance and Capability of a Mixed-Flow Multiphase Pump ». Dans ASME Turbo Expo 2016 : Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/gt2016-56576.
Texte intégralRésumé :
Multiphase flow introduces many challenges in turbomachines analysis and operation, as each of the phases responds differently to the forces in the hydraulic channel, and the mechanical and thermal interaction among the phases has to be taken into account too. Especially when very high gaseous fractions need to be covered, due to the concurrent physics involved and transient phenomena, a proper machine characterization cannot be limited to an overall description of the performance, but it needs to rely on advanced analysis tools which can reveal the local phenomena responsible for performance degradation and instabilities. The flow regimes vary from a homogeneous distribution of fine bubbles, evenly dispersed and carried away by the main flow, to more complex flow patterns, especially if bubbles coalesce and adhere to a wide portion of the channel wall. Tests are performed on a multiphase pump facility recently designed by the authors, which allows a complete optical access to the pump channels and fine adjustments in the inlet configuration and the tip clearance gap. The investigation focuses on the effect of the mixture inlet pressure and machine rotational speed on performance and stability. Increasing values of the inlet pressure reduce the density ratio between the phases, thus making them become more coupled; this results in a milder performance degradation and a wider stable operating range. Accurate flow visualization through the pump transparent casing complements the study, allowing an immediate and detailed local phenomena description. The results are presented under performance and surging curves, showing the gas-handling capability dependence on the actual conditions. These analyses fully characterize the machine behavior, define the operating zones which should be avoided, and will serve later to implement a control strategy to keep the machine in a safe regime.
Rapports d'organisations sur le sujet "DYE DEGRADATION CAPABILITY"
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Adam, Zach, et Eran Pichersky. Degradation of Abnormal Proteins in Chloroplasts of Higher Plants. United States Department of Agriculture, août 1994. http://dx.doi.org/10.32747/1994.7568768.bard.
Texte intégralRésumé :
In this study we attempted to get a better understanding of processes involved in the degradation of abnormal proteins i chloroplasts. To achieve this goal, we used a number of complementary approaches. We first characterized the expression of the two subunits of Clp protease. We demonstrated that both of them were expressed in chloroplasts in a constitutive fashion, but the expression of the regulatory subunit ClpC was enhanced by light. We generated a mutant the lumenal protein OEE33 which was targeted to the stroma in in vitro experiments. In the wrong compartment it was found unstable, and characterization of its degradation revealed that it was degraded by a soluble, ATP-dependent serine protease, which are also the characteristics of Clp protease. In search of other homologues of bacterial proteases, we found that chloroplasts contain a homologue of the FtsH protease. It is an ATP-dependent metallo-protease, bound to the stromal side of the thylakoid membrane, whose expression is dependent on light. The gene encodig this protease was cloned and characterized. In attempt to generate Arabidopsis mutant plants impaired in their capability to degrade abnormal chloroplast proteins, we fused the gene for mistargeted OEE33 to the streptomycin-detoxifying gene. This chimeric gene was introduced into Arabodipsis plants, to generate transformed plants. This transformants plants were sensitive to streptomycin due to the rapid turn-over of the chimeric protein. Seeds from these plants were then chemically mutagenised, and seedlings were selected for their capability to grow on streptomycin. The ability of these mutant transformants to grow on streptomycin is presumably due to stabilization of the chimeric protein. These plants will allow us in the future to identify the effected genes, which are likely to be involved in the protein degradation process.
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Davies, Will. Improving the engagement of UK armed forces overseas. Royal Institute of International Affairs, janvier 2022. http://dx.doi.org/10.55317/9781784135010.
Texte intégralRésumé :
The UK government’s Integrated Review of security, defence, development and foreign policy, published in March 2021 alongside a supporting defence command paper, set a new course for UK national security and highlighted opportunities for an innovative approach to international engagement activity. The Integrated Review focused principally on the state threats posed by China’s increasing power and by competitors – including Russia – armed with nuclear, conventional and hybrid capabilities. It also stressed the continuing risks to global security and resilience due to conflict and instability in weakened and failed states. These threats have the potential to increase poverty and inequality, violent extremism, climate degradation and the forced displacement of people, while presenting authoritarian competitors with opportunities to enhance their geopolitical influence. There are moral, security and economic motives to foster durable peace in conflict-prone and weakened regions through a peacebuilding approach that promotes good governance, addresses the root causes of conflict and prevents violence, while denying opportunities to state competitors. The recent withdrawal from Afghanistan serves to emphasize the complexities and potential pitfalls associated with intervention operations in complex, unstable regions. Success in the future will require the full, sustained and coordinated integration of national, allied and regional levers of power underpinned by a sophisticated understanding of the operating environment. The UK armed forces, with their considerable resources and global network, will contribute to this effort through ‘persistent engagement’. This is a new approach to overseas operations below the threshold of conflict, designed as a pre-emptive complement to warfighting. To achieve this, the UK Ministry of Defence (MOD) must develop a capability that can operate effectively in weak, unstable and complex regions prone to violent conflict and crises, not least in the regions on the eastern and southern flanks of the Euro-Atlantic area. The first step must be the development of a cohort of military personnel with enhanced, tailored levels of knowledge, skills and experience. Engagement roles must be filled by operators with specialist knowledge, skills and experience forged beyond the mainstream discipline of combat and warfighting. Only then will individuals develop a genuinely sophisticated understanding of complex, politically driven and sensitive operating environments and be able to infuse the design and delivery of international activities with practical wisdom and insight. Engagement personnel need to be equipped with: An inherent understanding of the human and political dimensions of conflict, the underlying drivers such as inequality and scarcity, and the exacerbating factors such as climate change and migration; - A grounding in social sciences and conflict modelling in order to understand complex human terrain; - Regional expertise enabled by language skills, cultural intelligence and human networks; - Familiarity with a diverse range of partners, allies and local actors and their approaches; - Expertise in building partner capacity and applying defence capabilities to deliver stability and peace; - A grasp of emerging artificial intelligence technology as a tool to understand human terrain; - Reach and insight developed through ‘knowledge networks’ of external experts in academia, think-tanks and NGOs. Successful change will be dependent on strong and overt advocacy by the MOD’s senior leadership and a revised set of personnel policies and procedures for this cohort’s selection, education, training, career management, incentivization, sustainability and support.