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Artykuły w czasopismach na temat "Non lead oxide"
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Bagova, Zarina, Kurmanbek Zhantassov, Gaukhar Turebekova, Bayan Sapargaliyeva i Shermakhan Shapalov. "DISPOSAL OF LEAD PRODUCTION WASTES BY EXTRACTION OF LEAD AND ZINC OXIDES". Series of Geology and Technical Sciences 2, nr 446 (15.04.2021): 37–44. http://dx.doi.org/10.32014/2021.2518-170x.32.
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Information is given about the need to dispose of waste from the Shymkent lead plant in the form of slags, which have accumulated about 2 million tons. It is proved that lead production slags contain a large number of toxic compounds, such as lead, zinc, osmium, and cadmium, which are dangerous sources of environmental pollution. According to the results of X-ray diffractometric analysis and DTA, it was found that the slag of lead produc- tion contains a fairly high number of non-ferrous metal compounds: the content of lead oxide up to 2 %, zinc oxide up to 17% and copper oxide up to 1.25% of the total weight of the sample. The qualitative composition and content of non-ferrous metals of lead slags makes it possible to make the process of recycling toxic waste from lead production technically and economically feasible. The results of preliminary tests allow us to select a technology for more complete and selective extraction of lead and zinc oxides from the slag waste of lead production. When using a selective method for extracting non- ferrous metals, it is expected to improve the ecological state of the environment and reduce the negative impact on human health due to the disposal of toxic slags from lead production. At the same time, a significant contribution is made to the development of the system of rational use of natural and secondary resources.
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Gladinez, Kristof, Kris Rosseel, Jun Lim, Alessandro Marino, Geraldine Heynderickx i Alexander Aerts. "Formation and transport of lead oxide in a non-isothermal lead-bismuth eutectic loop". Nuclear Engineering and Design 349 (sierpień 2019): 78–85. http://dx.doi.org/10.1016/j.nucengdes.2019.04.021.
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Thiele, Günther, Thomas Krüger i Stefanie Dehnen. "K4[PbSe4]⋅en⋅NH3: A Non-Oxide, Non-Halide Inorganic Lead(IV) Compound". Angewandte Chemie International Edition 53, nr 18 (20.03.2014): 4699–703. http://dx.doi.org/10.1002/anie.201310455.
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Li, Cheng Peng, Mary She i Ling Xue Kong. "Non-Isothermal Crystallization Kinetics of Polyvinyl Alcohol-Graphene Oxide Composites". Applied Mechanics and Materials 446-447 (listopad 2013): 206–9. http://dx.doi.org/10.4028/www.scientific.net/amm.446-447.206.
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Polyvinlyl alcohol (PVA)/graphene oxide (GO) composites are prepared by solution blending method. And the non-isothermal crystallization kinetics of as-prepared composites is evaluated by differential scanning calorimetry (DSC). The results indicate the graphene oxide can significantly modify the non-isothermal crystallization behavior of the PVA, for instance improved crystallization temperature and prolonged crystallization time. Enhanced crystallization temperature illustrates that GO can act as effective nucleating agent. However, prolonged crystallization time means that GO can retard the whole crystallization. Further kinetics analysis indicates that both the crystallization kinetics of neat PVA and PVA/GO match the Mo model very well. According to the Mo model, during the whole crystallization process, graphene oxide perform as a retardant. In conclusion, graphene oxide can act as effective nucleating agent due to strong interaction bewteen graphene oxide and PVA matrix. On the other hand, graphene oxide loaded may lead to other side effects. This side effects may lead to the retarded crystallization speed finally.
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Thiele, Guenther, Thomas Krueger i Stefanie Dehnen. "ChemInform Abstract: K4[PbSe4]·en·NH3: A Non-Oxide, Non-Halide Inorganic Lead(IV) Compound." ChemInform 45, nr 28 (26.06.2014): no. http://dx.doi.org/10.1002/chin.201428018.
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Skobeev, D., i A. Legkikh. "INVESTIGATION OF THE CHARACTERISTICS OF LEAD OXIDE GRANULES AFTER PROLONGED EXPOSURE IN LIQUID LEAD". PROBLEMS OF ATOMIC SCIENCE AND TECHNOLOGY. SERIES: NUCLEAR AND REACTOR CONSTANTS 2021, nr 3 (26.09.2021): 184–90. http://dx.doi.org/10.55176/2414-1038-2021-3-184-190.
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In order to ensure the safe operation of reactor installations under development with heavy liquid metal coolants (HLMC), such as lead and lead-bismuth, it is necessary to address issues related to the control and regulation of the oxygen potential of the coolant. This is necessary to maintain the normalized range of dissolved oxygen concentrations to ensure the conditions for the formation and maintenance of the integrity of protective oxide coatings on structural materials, as well as to prevent the formation of oxide slags from the coolant during the operation of the reactor plant. Specialists of IPPE have developed a method and a means of solid-phase regulation of the thermo-dynamic activity of oxygen in HLMC. In mass transfer devices developed for the implementation of the solid-phase method of controlled feeding of a heavy liquid metal coolant with dissolved oxygen, lead oxide granules are used as a filler. One of the important issues in substantiating the reliability of mass transfer devices is the question of the constancy of the mechanical properties and chemical composition of lead oxide granules after their prolonged stay under the level of a heavy liquid metal coolant at operating temperature. The lead oxide granules were aged in a sealed container filled with lead. The tank was equipped with the necessary means to control the temperature of the lead and the pressure of the protective gas (argon). The article presents the results of experimental studies of lead oxide granules after their exposure in a lead melt at a temperature of (420±10) °C in a non-carbon mode for 6000 hours. To investigate the characteristics of the lead oxide pellets, a batch of pellets was excavated after 500, 750, 1000, 1750, 2500, 3000, 4500 and 6000 hours from the start of the tests. For the pellets from each recess, the following studies were performed: - pellet density measurements; - measurement of breaking forces of lead oxide granules; - determination of pellet impact strength; - chemical analysis of granule composition.
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Blankenburg, Jan, Martin Stark i Holger Frey. "Oxidation-responsive polyether block copolymers lead to non-ionic polymer surfactants with multiple amine N-oxides". Polymer Chemistry 10, nr 13 (2019): 1569–74. http://dx.doi.org/10.1039/c9py00093c.
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Tallant, D. R., R. W. Schwartz, B. A. Tuttle, S. C. Everist i B. C. Tafoya. "Raman analysis of microcircuits with lead zirconate titanate (PZT) films". Proceedings, annual meeting, Electron Microscopy Society of America 50, nr 2 (sierpień 1992): 1688–89. http://dx.doi.org/10.1017/s0424820100133072.
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Certain compositions and structural forms of lead zirconate titanate (PZT) materials have potential applications in microelectronics because of their ferroelectric properties. One such application is in the development of new types of non-volatile memories. PZT films are integrated into microcircuit components using sol-gel deposition techniques. The solution chemistry effects attendant to different sol-gel preparation procedures have been investigated by several researchers.We have used Raman spectroscopy both to characterize the metallo-organic species initially laid down on macroscopic platinum substrates during sol-gel processing and to follow the evolution of Pb-Zr-Ti oxide species through high temperature processing. The high temperature processing removes residual organics and creates Pb-Zr-Ti oxide structures that have ferroelectric properties. Low temperature pyrochlore structures, which are not ferroelectric, can be distinguished by Raman spectroscopy from tetragonal and pseudo-cubic/rhombohedral perovskite structures, which are usefully ferroelectric (Top Figure). In addition Raman spectroscopy has identified lead and titanium oxides that form as intermediates in the high temperature crystallization of ferroelectric PZT structures.
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Vusikhis, Alexander S., Evgeny N. Selivanov, Stanislav N. Tyushnyakov i Victor P. Chentsov. "Thermodynamic modeling of reduction of metals from B2O3-CaO-Ni(Zn,Pb,Cu)O melts carbon monoxide". Butlerov Communications 59, nr 9 (30.09.2019): 125–31. http://dx.doi.org/10.37952/roi-jbc-01/19-59-9-125.
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Thermodynamic modeling technique is used to describe the metal reduction from oxide melt by carbon monoxide. The B2O3-CaO-MeO (Me – Ni, Zn, Pb, Cu) system, was used with periodic output of the metal phase and gases from the working body. The approach originality is that the equilibrium is determined for each single portion of the gas injected into the working body, and the metal oxides content being reduced in each calculation cycle is taken from the previous data. This approach gives qualitative possibility to make simulated processes closer to real ones. The proposed method calculations allow determining, such parameters as the oxide melt and metal phase compositions, degree of elements reduction, oxide and metal phases mass ratio, equilibrium composition of the gas, reducing ability of gas utilization degree, and others, depending on the introduced gas quantities. Reducing process modeling of Nickel, Copper, Lead and Zinc from B2O3-CaO-MeO melts gives opportunity to determine the process for each metal. Copper reducing from CuO, goes with intermediate oxide (CuO → Cu2O → Cu) formation. Reduction of Nickel (NiO → Ni), Lead (PbO → Pbs + Pbg) and Zinc (ZnO → Zng) proceeds in one stage. The temperature dependence of the non-ferrous metals content in the oxide melt, its reduction degree and reducing agent quantity introduced are described by the second-order polynomial equations. The information obtained may be useful for thermo-extraction processes prognosis during the Nickel, Copper, Lead, and Zinc extraction from non-ferrous metallurgy slag in bubbling process of oxide melt by reducing gases.
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Kirkbir, F., D. Katz, R. Lysse i J. D. Mackenzie. "Formation of dense and non-agglomerated lead oxide particles by spray pyrolysis". Journal of Materials Science 27, nr 7 (1992): 1748–56. http://dx.doi.org/10.1007/bf01107199.
Pełny tekst źródłaRozprawy doktorskie na temat "Non lead oxide"
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Kumari, Mukesh. "Synthesis and characterization of non lead based oxide systems for magnetoelectric multiferroic properties". Thesis, IIT Delhi, 2016. http://localhost:8080/iit/handle/2074/7114.
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Le, Lay Luc. "Mise en forme et etude de filaments supraconducteurs a base de phases de chevrel". Rennes 1, 1988. http://www.theses.fr/1988REN10126.
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Elaboration et etude de filaments pbmo::(6)s::(8) et snmo::(6)s::(8) et des massifs de ces memes materiaux. Etude des comportements mecanique, chimique et supraconducteur des massifs. Optimisation de la composition de la poudre d'un brin monofilamentaire en fonction des dopants, de la stoechiometrie et de la nature des poudres de base. Optimisation des traitements des filaments: des traitements a haute temperature (950**(o)c a 1000**(o)cpounds et pendant des durees relativement courtes (0,5 a 2 h) permettent d'obtenir les meilleurs resultats de densites de courant critique. Realisation de bobinettes permettant d'atteindre des densites de courant critique de 10**(8) a/m**(2) a 14 t
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Vičíková, Magda. "Vliv listového dusíku a nestrukturních sacharidů na obsah a aktivitu enzymu Rubisco v podmínkách normální a zvýšené koncentrace oxidu uhličitého". Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2011. http://www.nusl.cz/ntk/nusl-216719.
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This diploma thesis examines influence of content of leaf nitrogen and non-structural carbohydrates on Rubisco activity and its content under impact of ambient (A = 385 µmolCO2 mol-1) and elevated (E = 700 µmolCO2 mol-1) concentrations of carbon dioxide in needles of Norway spruce (Picea abies L.). The Rubisco activity was determined spectrophotometrically, the Rubisco content by using SDS-PAGE, the content of non-structural carbohydrates by using the anthron method and total leaf nitrogen was determined by using the Kjeldahl method. The Rubisco activity in needles of Norway spruce did not show acclimation on elevated concentration of carbon dioxide, but the activity was elevated concentration of carbon dioxide stimulated during the growing season. The acclimation was proved by Rubisco content, its content was significantly lower in needles cultivated under elevated carbon dioxide. Content of total leaf nitrogen was statistically significantly lower in needles of Norway spruce cultivated under elevated carbon dioxide then in needles cultivated under ambient concentration of carbon dioxide. On the contrary, the content of non-structural carbohydrates was significantly higher in needles cultivated under elevated concentration of carbon dioxide then in variant A. Seasonal changes of Rubisco content depended on content of non-structural carbohydrates, the Rubisco content decreased with increasing content of non-structural carbohydrates. No dependence was detected between seasonal changes of the total leaf content and the Rubisco content.
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Chaillout-Bougerol, Catherine. "Contribution à l'étude du système BaPb(1-x)Bi(x)O(3) : relations entre les propriétés structurales, chimiques et physiques". Grenoble 1, 1986. http://www.theses.fr/1986GRE10017.
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Etude de la solution solide du titre du fait de l'interet suscite par ses proprietes physiques : phrase supraconductrice pour 0,05 x 0,30 avec tc# 13k, transition metal-semiconducteur pour x # 0,30. La structure de ces composes est de type perovskite. Selon la concentration en pb et bi, la structure de base cubique se deforme differemment. Etude de la valence de bi et de la stoechiometrie en oxygene, dans babi0::(3) en particulier. Proposition de modeles qui permettent de concilier divers resultats publies anterieurement concernant les proprietes structurales et physiques
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Singh, Amrita. "Structural and electrical characterization of non lead based oxides near MPB". Thesis, 2013. http://localhost:8080/iit/handle/2074/6713.
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Gevers, Sebastian. "Praseodymia on non-passivated and passivated Si(111) surfaces". Doctoral thesis, 2011. https://repositorium.ub.uni-osnabrueck.de/handle/urn:nbn:de:gbv:700-201107048169.
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In the presented thesis thin praseodymia films on non-passivated and passivated Si(111) substrates were investigated. The first part deals with PDA of praseodymia films with fluorite structure under UHV conditions in the temperature region from RT to 600°C. Here, a sophisticated model of the annealing process of praseodymia films is established. This is done by detailed analysis of XRD measurements using the kinematic diffraction theory in combination with the analysis of GIXRD, XRR and SPA-LEED measurements. It is shown that the untreated films, which are oxidized in 1 atm oxygen to obtain fluorite structure, do not exhibit pure PrO2 stoichiometry as it was assumed before. Instead, they decompose into two laterally coexisting species exhibiting a PrO2 and a Pr6O11. oxide phase, respectively. These species are laterally pinned to the lattice parameter of bulk Pr6O11. Homogeneous oxide films with Pr6O11 phase can be observed after annealing at 100°C and 150°C. Here, lateral strain caused by the pinning of the species is minimized and an increase of the crystallite sizes is determined. If higher annealing temperatures are applied, the film decomposes again into two coexisting species. Finally, after annealing at 300°C, a mixed crystalline film with both Pr2O3 and Pr2O3+Delta oxide phases is formed, where Delta denotes a considerable excess of oxygen within the sesquioxide phase. Again the lateral strain increases due to the tendency of praseodymia phases to increase their lattice parameters during oxygen loss combined with the lateral pinning. This is accompanied by a decrease of crystallite sizes, which are afterwards comparable to those of the untreated films. Further annealing at temperatures above 300°C does not significantly change the structure of the oxide film. However, the increase of the amorphous Pr-silicate interface between Si substrate and oxide at the expense of the crystalline oxide can be observed after annealing at higher temperatures. Furthermore, an increased mosaic spread of the crystallites occurs, which reduces the lateral strain caused by the oxygen loss. Nevertheless, the crystalline structure is stable against further annealing up to temperatures of 600°C. Transportation of the sample under ambient conditions after annealing at 200°C and 300°C leads to the formation of an additional crystalline structure at the surface which cannot be allocated to any praseodymia phase and may be explained by the contamination of the topmost crystalline layers with Pr-hydroxides. The results obtained from praseodymia films annealed in 1 atm nitrogen show that these films are good candidates to form homogeneous oxide films with pure cub-Pr2O3 structure by subsequent annealing in UHV. Here, a single oxide species is already observed after annealing at 300°C by SPA-LEED measurements which is in contrast to praseodymia films with fluorite structure where higher annealing temperatures (600°C) are necessary. In this case, negative effects like interface growth or increased defect density (mosaics, grain boundaries) can be minimized. Investigations on oxygen plasma-treated praseodymia films to obtain pure PrO2 stoichiometry are presented in the second part. Oxygen plasma-treated samples are compared with samples oxidized in 1 atm oxygen regarding the structure of the crystalline film. For this purpose, XRR and XRD measurements are performed to get structural information of the oxide film, which can be used to identify the corresponding oxide phases. Here, significantly smaller lattice constants of the crystalline oxide species can be observed after plasma treatment, which points to the incorporation of additional oxygen atoms. This verifies former studies, where a higher oxidation state of the oxide film was found by XPS measurements and it shows that plasma-treated films exhibit a higher oxidation state than films oxidized in 1 atm oxygen due to the availability of reactive atomic oxygen in the plasma. Furthermore, the Pr-silicate interface between crystalline film and Si substrate is not increased during plasma treatment. In the last part of the presented thesis, first results from the epitaxy of praseodymia films on Cl-passivated Si substrates are shown. The aim is to suppress the Pr-silicate formation during the growth process. Thus, praseodymia films are grown on passivated and non-passivated substrates to compare the crystallinity of both samples using XSW and LEED measurements. The structure of the oxide films on Cl-passivated Si is determined afterwards by XRR. It is shown that crystalline films with cub-Pr2O3 structure and several nanometer thickness can be successfully grown on Cl-passivated substrates. Here, the Pr-silicate interface layer are restricted to a single mono-layer. In contrast, the films grown on non-passivated substrates are completely amorphous containing Pr-silicates and Pr-silicides.
Książki na temat "Non lead oxide"
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Litell, John M., i Nathan I. Shapiro. Pathophysiology of septic shock. Oxford University Press, 2016. http://dx.doi.org/10.1093/med/9780199600830.003.0297.
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The pathophysiology of sepsis is the result of a dysregulated host response to infection. Interactions between conserved pathogenic signals and host recognition systems initiate a systemic reaction to local infection. Pro- and anti-inflammatory intermediates and associated coagulatory abnormalities lead to altered macrovascular, microvascular, and mitochondrial function. Uncorrected, these processes yield similar patterns of failure in multiple organ systems. Mortality increases with successive organ failures. Although commonly thought to be a manifestation of impaired renal circulation, septic acute kidney injury may be due primarily to non-haemodynamic factors. Pulmonary parenchymal dysfunction in sepsis also contributes to failures in other organ systems. Sepsis involves complex alterations in myocardial function, vascular tone, and capillary integrity, which are mediated by elevated concentrations of inflammatory cytokines, inducible nitric oxide, and reactive oxygen species, among others. Gut hypomotility and translocation of enteric flora likely contribute to a persistent inflammatory response. This perpetuates the pathophysiological pattern of sepsis, and can lead to the delayed onset of these features in patients with other types of critical illness. The neurological manifestations of sepsis include acquired delirium, which is also probably due to circulatory and inflammatory abnormalities, as well as alterations in cerebral amino acid metabolism. Critical illness-related corticosteroid insufficiency and derangements in glucose metabolism are among the endocrine abnormalities commonly seen in septic patients. Restoration of homeostasis requires early haemodynamic resuscitation and aggressive infectious source control.
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Partridge, Christopher. Anesthetic Revelation. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780190459116.003.0004.
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This chapter explores the fascinating confluence of medicine and metaphysics during the nineteenth century, central to which was the discovery of anesthetics. Often a visit to the dentist led not only to a tooth extraction but also to a “sublime vision” and a revised understanding of the nature of reality. Accounts of such experiences inspired not only revealing popular works on the “laughing gas” phenomenon, such as Doctor Syntax in Paris or A Tour in Search of the Grotesque, but also discussions of the nature of mystical experience. This chapter analyzes the work of key figures influenced by the inhalation of nitrous oxide, including Humphry Davy, Benjamin Paul Blood, and William James, as well as its impact on the work of the Society for Psychical Research.
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Frew, Anthony. Air pollution. Redaktorzy Patrick Davey i David Sprigings. Oxford University Press, 2018. http://dx.doi.org/10.1093/med/9780199568741.003.0341.
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Any public debate about air pollution starts with the premise that air pollution cannot be good for you, so we should have less of it. However, it is much more difficult to determine how much is dangerous, and even more difficult to decide how much we are willing to pay for improvements in measured air pollution. Recent UK estimates suggest that fine particulate pollution causes about 6500 deaths per year, although it is not clear how many years of life are lost as a result. Some deaths may just be brought forward by a few days or weeks, while others may be truly premature. Globally, household pollution from cooking fuels may cause up to two million premature deaths per year in the developing world. The hazards of black smoke air pollution have been known since antiquity. The first descriptions of deaths caused by air pollution are those recorded after the eruption of Vesuvius in ad 79. In modern times, the infamous smogs of the early twentieth century in Belgium and London were clearly shown to trigger deaths in people with chronic bronchitis and heart disease. In mechanistic terms, black smoke and sulphur dioxide generated from industrial processes and domestic coal burning cause airway inflammation, exacerbation of chronic bronchitis, and consequent heart failure. Epidemiological analysis has confirmed that the deaths included both those who were likely to have died soon anyway and those who might well have survived for months or years if the pollution event had not occurred. Clean air legislation has dramatically reduced the levels of these traditional pollutants in the West, although these pollutants are still important in China, and smoke from solid cooking fuel continues to take a heavy toll amongst women in less developed parts of the world. New forms of air pollution have emerged, principally due to the increase in motor vehicle traffic since the 1950s. The combination of fine particulates and ground-level ozone causes ‘summer smogs’ which intensify over cities during summer periods of high barometric pressure. In Los Angeles and Mexico City, ozone concentrations commonly reach levels which are associated with adverse respiratory effects in normal and asthmatic subjects. Ozone directly affects the airways, causing reduced inspiratory capacity. This effect is more marked in patients with asthma and is clinically important, since epidemiological studies have found linear associations between ozone concentrations and admission rates for asthma and related respiratory diseases. Ozone induces an acute neutrophilic inflammatory response in both human and animal airways, together with release of chemokines (e.g. interleukin 8 and growth-related oncogene-alpha). Nitrogen oxides have less direct effect on human airways, but they increase the response to allergen challenge in patients with atopic asthma. Nitrogen oxide exposure also increases the risk of becoming ill after exposure to influenza. Alveolar macrophages are less able to inactivate influenza viruses and this leads to an increased probability of infection after experimental exposure to influenza. In the last two decades, major concerns have been raised about the effects of fine particulates. An association between fine particulate levels and cardiovascular and respiratory mortality and morbidity was first reported in 1993 and has since been confirmed in several other countries. Globally, about 90% of airborne particles are formed naturally, from sea spray, dust storms, volcanoes, and burning grass and forests. Human activity accounts for about 10% of aerosols (in terms of mass). This comes from transport, power stations, and various industrial processes. Diesel exhaust is the principal source of fine particulate pollution in Europe, while sea spray is the principal source in California, and agricultural activity is a major contributor in inland areas of the US. Dust storms are important sources in the Sahara, the Middle East, and parts of China. The mechanism of adverse health effects remains unclear but, unlike the case for ozone and nitrogen oxides, there is no safe threshold for the health effects of particulates. Since the 1990s, tax measures aimed at reducing greenhouse gas emissions have led to a rapid rise in the proportion of new cars with diesel engines. In the UK, this rose from 4% in 1990 to one-third of new cars in 2004 while, in France, over half of new vehicles have diesel engines. Diesel exhaust particles may increase the risk of sensitization to airborne allergens and cause airways inflammation both in vitro and in vivo. Extensive epidemiological work has confirmed that there is an association between increased exposure to environmental fine particulates and death from cardiovascular causes. Various mechanisms have been proposed: cardiac rhythm disturbance seems the most likely at present. It has also been proposed that high numbers of ultrafine particles may cause alveolar inflammation which then exacerbates preexisting cardiac and pulmonary disease. In support of this hypothesis, the metal content of ultrafine particles induces oxidative stress when alveolar macrophages are exposed to particles in vitro. While this is a plausible mechanism, in epidemiological studies it is difficult to separate the effects of ultrafine particles from those of other traffic-related pollutants.
Części książek na temat "Non lead oxide"
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Uheda, Kyota. "Application of Nitride and Oxynitride Compounds to Various Phosphors for White LED". W SiAlONs and Non-oxides, 15–18. Stafa: Trans Tech Publications Ltd., 2008. http://dx.doi.org/10.4028/3-908454-00-x.15.
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Mikami, Masayoshi, Satoshi Shimooka, Kyota Uheda, Hiroyuki Imura i Naoto Kijima. "New Green Phosphor Ba3Si6O12N2:Eu for White LED: Crystal Structure and Optical Properties". W SiAlONs and Non-oxides, 11–14. Stafa: Trans Tech Publications Ltd., 2008. http://dx.doi.org/10.4028/3-908454-00-x.11.
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Lobato, Lydia Maria, Rosaline Cristina Figueiredo e Silva, Thomas Angerer, Mônica de Cássia Oliveira Mendes i Steffen G. Hagemann. "Iron Isotopes Applied to BIF-Hosted Iron Deposits". W Isotopes in Economic Geology, Metallogenesis and Exploration, 399–432. Cham: Springer International Publishing, 2023. http://dx.doi.org/10.1007/978-3-031-27897-6_13.
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AbstractPublished and unpublished iron isotope data from banded iron formations (BIF) and their BIF-hosted hypogene (hydrothermal) iron ores from the Quadrilátero Ferrífero (itabirites), Corumbá, and Carajás iron districts in Brazil, as well as from the Hamersley province in Australia are presented and discussed. BIF constitutes a typically thinly bedded or laminated chemical sedimentary rock, with ≥ 15% Fe and layers of chert, chalcedony, jasper, or quartz, whereas itabirite is considered a laminated, metamorphosed iron formation rich in iron oxides, which may contain carbonate minerals, amphiboles, and abundant quartz. For the Paleoproterozoic Quadrilátero Ferrífero district, the range in δ56Fe values of hypogene iron ores is similar to that of the metamorphosed BIFs, and iron isotope variations are better distinguished in different regional deformational domains. Light isotopic compositions dominate in the low deformation domain (δ56Fe = −0.42 ± 0.12 to 0.29 ± 0.04‰), whereas the eastern, high-strain domain is characterized by heavy values (δ56Fe = −0.09 ± 0.08 to 0.37 ± 0.06‰; Mendes et al., Mineral Deposita 52:159–180, 2017). Iron isotope composition for the Neoproterozoic iron formations of the Corumbá region (hematitic, dolomite-rich: −1.83 and −0.83‰; cherty-hematite: δ56Fe −0.49‰) are controlled by: (1) primary seawater signature, (2) microbial activity, and (3) supergene goethite alteration. Hydrothermal alteration is reflected in the oxygen isotope data, but apparently not in the iron isotope fractionation. Iron and oxygen isotope pairing shows that δ56Fe values increase, while δ18O values decrease. In the Archean jaspilites of Carajás, hypogene ores tend to display lighter δ56Fe values than their host BIF counterparts. Also, there is a correlation between coupled iron and oxygen isotope values that is clearer towards lighter isotopic values, especially for δ18O. In the Paleoproterozoic Hamersley deposits, correlation between δ18O and δ56Fe values suggests a direct correlation of both isotope systems during low-grade, greenschist-facies metamorphism. On the other hand, despite the evident shift to negative δ18O values and apparent preservation of the metamorphic δ56Fe signature, iron ore and hydrothermally modified BIF show a correlation between δ18O and δ56Fe values. In contrast, in supergene-modified samples a negative correlation is apparent. The Carajás (+1.24 to + 0.44; one sample − 0.30‰) and Hamersley (+ 1.02 to − 0.29‰) hypogene ores display δ56Fe in a similar interval, reaching positive values, whereas ores from the Quadrilátero Ferrífero show a tendency towards lower values (to − 0.80‰). This review indicates that the application of iron isotopes in exploration is presently limited mainly due to the restricted dataset available for ore samples. Nevertheless, and despite all local differences, there is a general tendency for hypogene ores to display moderately lighter δ56Fe values for all deposits compared to precursor BIF. In contrast, a strong supergene imprint in ore leads to moderately heavier δ56Fe values. As more data become available, and if these trends are confirmed, the use of this tool may be valuable in the future, for instance to decipher the hypogene or supergene origin of specific ore zones, and as a consequence the probable depth extension or interpretation of concealed, deep orebodies.
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Rangaraj, Lingappa, Canchi Divakar i Vikram Jayaram. "Processing of Ultra-High Temperature Ceramics for Hostile Environments". W MAX Phases and Ultra-High Temperature Ceramics for Extreme Environments, 100–124. IGI Global, 2013. http://dx.doi.org/10.4018/978-1-4666-4066-5.ch004.
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A detailed review of the processing of zirconium, hafnium, and tantalum based boride-carbide-nitride composites is presented. The processing methodology and important steps involved in producing a pore-free microstructure are reported. The effect of addition of secondary and ternary compounds on densification is highlighted as is the reactive processing of ultra-high temperature ceramics (UHTCs) based on zirconium carbide through the formation of a transient non-stoichiometric carbide and transient liquid phase, which enable densification at much lower temperatures. The reactive processing method is promising in that it readily leads to variation in the composition of secondary/ternary non-oxide phases in the composites as well as the incorporation of fibres which may otherwise degrade. Since the processing temperatures are lower, the grain size obtained after densification is finer and may lead to better mechanical properties (hardness, fracture toughness, and strength). Processing of fibre based composites with boride particulates and silicon carbide through the ceramic precursor route are also discussed.
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Chouhan, Er R. K., i Manish Mudgal. "Novel Radiation Shielding Concrete Utilizing Industrial Waste for Gamma-Ray Shielding". W Smart Materials Design for Electromagnetic Interference Shielding Applications, 527–54. BENTHAM SCIENCE PUBLISHERS, 2022. http://dx.doi.org/10.2174/9789815036428122010015.
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For the first time, the capability of red mud waste has been explored for the development of advanced synthetic radiation shielding aggregate and radiation shielding concrete. Red mud, an aluminium industry waste, consists of multi.component and multi-elemental characteristics. Approximately two tons of red mud are generated for every ton of aluminium production. There are about 85 alumina plants all over the world, thus leading to the generation of about 77 million tons of highly alkaline waste annually. The major mineral content of red mud waste includes hematite, anatase, and cancrinite, thus making red mud waste the most suitable multi.component resource material for developing multi phases containing shielding aggregate. Further, these multi-elements in the red mud are present in the form of oxide, oxy-hydroxide, and hydroxides, having low as well as high atomic number elements, namely sodium, iron, titanium compounds, respectively, and are non-toxic in nature. The concrete possessing specific gravity higher than 2600 kg/m3 is known as heavyweight concrete, and aggregate with specific gravities higher than 3000 kg/m3 is called heavyweight aggregate as per TS EN 206-1 (2002). The shielding aggregate contains both naturally occurring as well as some of the artificial aggregate. The natural aggregate includes hematite, magnetite, limonite barite, etc., which are non.replenishable and are useful for many other important applications, and the artificial aggregate includes the use of iron shots and steel filing and in some cases, lead shots, etc. The use of lead shots makes the material toxic in nature, therefore, there is a need to avoid the use of lead-based materials for shielding applications, as it ranks second in the list of hazardous materials. Apart from toxicity associated with lead, the low melting point of lead is also prohibitive as the shielding concrete should be preferably heat and fire-resistant. Further, all the natural minerals inherently contain only a single shielding phase, therefore, conventionally shielding concretes are developed by a combination of various natural minerals, which leads to an inhomogeneous radiation shielding matrix in the developed conventional radiation shielding concrete. In view of the above, there is an urgent need to develop advanced non-toxic synthetic shielding aggregate capable of providing homogeneous radiation shielding matrix preferably obviating the use of toxic lead and conventional non-replenishable natural minerals resources. In this chapter, aluminium industrial waste, i.e., red mud, has been utilized. Chemical formulation and mineralogical designing of the red mud has been done by ceramic processing using appropriate reducing agents and additives. The chemical analysis, SEM microphotographs, and XRD analysis confirm the presence of multi-component, multi shielding, and multi-layered phases in developed advanced synthetic radiation shielding aggregate. The maximum density of developed synthetic aggregate is found to be 4.16 g/cc. The mechanical properties, namely aggregate impact value, aggregate crushing value, and aggregate abrasion value, have been evaluated and was compared with hematite ore aggregate and found to be an excellent material useful for making advanced radiation shielding concrete for the construction of nuclear power plants and other radiation installations. For the first time, the development and design mix of novel radiation shielding concrete using innovative red mud-based synthetic shielding aggregates have been carried out in which the heavy density shielding aggregates are developed using red mud and are basically ceramic materials consisting of shielding phases, namely barium silicate (san-bornite), barium iron titanium silicate (bafertisite), barium aluminium silicate, iron titanium oxide (pseudorutile), barium titanate, barium iron titanium oxide, barium aluminium oxide, and magnetite, which are multi-elemental, multi phases, multi-layered crystal structures, therefore, they are excellent shielding materials. The radiation shielding concrete was made using developed synthetic shielding aggregates adopting IS 10262-2009 standard for grade designation of M-30 concrete. The reference hematite ore concrete and developed concrete tested for radiation shielding attenuation properties for gamma rays using 137Cs (of photon energy 662 keV) and 241Am (of photon energy 60 keV) were found to possess highly effective shielding properties. The developed novel design mix concrete achieved an attenuation factor of 5.8 as compared to 5.1 attenuation factor for reference hematite ore concrete. The developed radiation shielding concrete using red mud-based synthetic shielding aggregates possess a broad application spectrum ranging from the construction of diagnostic X-ray, CT scanner rooms, and storing radioactive waste to nuclear power plants.
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Rickard, David. "Framboid Mineralogy". W Framboids, 153–68. Oxford University Press, 2021. http://dx.doi.org/10.1093/oso/9780190080112.003.0008.
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Framboids are dominantly made of pyrite. The limiting factors for other minerals forming framboids include the requirements of crystal habit, solubility, and natural abundances of the constituent elements for framboid formation. Detailed examination of reports of non-pyritic framboids reveal microcrystalline material within and associated with framboids (e.g., greigite) and sub-spherical crystalline aggregates (e.g., marcasite, chalcocite-digenite, magnetite). Framboids are sometimes observed replaced by other minerals. Pyrite framboids are often formed during the earliest stages of sedimentation or mineralization and therefore are subject to further reactions with later fluids. Minerals such as copper, cobalt, zinc, and lead sulfides often display framboidal forms that have replaced original pyrite framboids. Likewise, oxidation of pyrite under some conditions can produce iron (oxyhydr)oxide and iron sulfate framboids.
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Ravichandran, Veerasamy, Karunakaran Rohini, Anitha Roy i S. Rajeshkumar. "Microbial Mediated Synthesis, Characterisation and Application of Selenium Nanoparticles". W Mycology: Current and Future Developments, 62–102. BENTHAM SCIENCE PUBLISHERS, 2022. http://dx.doi.org/10.2174/9789815051360122030007.
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The development in nanotechnology, specifically the nanoparticulate system, has a great impact on medicine, engineering and other scientific areas. Inorganic nanoparticles such as silver, gold, zinc oxide, selenium, iron, lead, platinum and copper, etc. were found to exhibit antimicrobial, antioxidant and other biological activities, used as biosensors and also used in different fields of engineering. In the 21st century, microorganisms and plant parts are playing a major role in the synthesis of inorganic nanoparticles. Green synthesis of inorganic nanoparticles becomes preferable to other approaches because of its eco-friendly and non-toxic approach. Additionally, the active molecules of plants (Tannins, flavonoids, terpenoids, saponins, proteins and glycosides) which act as capping and reducing agents in the synthesis of metal nanoparticles could make them most suitable for biomedical applications. This green approach fascinated researchers across the globe to explore the potential of different microorganisms and plants in the synthesis of inorganic nanoparticles. Selenium nanoparticles are one of the inorganic nanoparticles which are widely used in the area of medicine and engineering. In this chapter, we discussed the green synthesis using microorganism and Agri based products, characterisation and various applications of selenium nanoparticles.
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Bunker, Bruce C., i William H. Casey. "Bio-inspired Synthesis of Oxide Nanostructures". W The Aqueous Chemistry of Oxides. Oxford University Press, 2016. http://dx.doi.org/10.1093/oso/9780199384259.003.0015.
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Nature is capable of building magnificently intricate and detailed structures out of otherwise boring materials such as calcium carbonate and silica. Anyone who has taken their children to see dinosaurs at a Natural History museum or visited natural wonders such as the Petrified Forest in Arizona are familiar with the natural process called fossilization by which the tissues of dead organisms are eventually replicated by objects of stone. Most living organisms (including humans) are critically dependent on more deliberate and controlled biomineralization phenomena that lead to the production of all hard tissues, including our teeth and bones, seashells and diatom skeletons, egg shells, and the magnetic nanoparticles that provide homing devices from bacteria to birds. All these processes are nothing more than specific examples of highly controlled nucleation and growth phenomena such as those described in generic terms in Chapter 7. At a molecular level, these processes are controlled by the same reaction mechanisms involving oxide surfaces, which were outlined in Chapter 6. However, biomineralization is orders of magnitude more sophisticated than standard nucleation and growth processes. The unique features of biomineralization involve the interplay between organic biomolecules and the nucleation and growth of inorganic phases such as oxides. This interplay is of critical importance in both biology and emerging nanotechnologies, providing specific examples that illustrate many of the concepts of oxide chemistry introduced in Chapters 5 through 7. In this chapter, we highlight the key concepts of biomineralization and provide examples of how researchers can now produce complex nanostructured oxides via biomimetic nucleation and growth strategies that replicate some of the key features used to make hard tissues in living systems. These strategies include the use of (1) molecular complexation and compartmentalization to control supersaturation levels, (2) specific ligands and surface structures to mediate nucleation phenomena, (3) hierarchical self-assembled organic architectures as templates for oxide formation, (4) functionalization to stimulate desired heterogeneous nucleation and growth processes on those templates, and (5) organic surfactants to manipulate both crystal-phase preferences and growth habits.
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Predoanǎ, Luminita, Dániel Attila Karajz, Vincent Otieno Odhiambo, Irina Stanciu, Imre M. Szilágyi, György Pokol i Maria Zaharescu. "Influence of the Microwaves on the Sol-Gel Syntheses and on the Properties of the Resulting Oxide Nanostructures". W Microwave Heating - Electromagnetic Fields Causing Thermal and Non-Thermal Effects. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.94931.
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Among the chemical methods in the liquid phase, the sol–gel technique is a versatile and efficient method for pure or doped metal oxide films or powders preparation, showing some advantages over other preparation techniques (high homogeneity, the possibility to introducing dopants in large amount, low processing temperature and control over the stoichiometry). Combining the sol–gel (SG)method with the effect of ultrasounds(US) or microwaves (MW) leads to improving the sol–gel procedure. The microwave-assisted sol–gel method is most frequently used for obtaining nanocrystalline, monodispersed oxide nanoparticles, or to transform amorphous gels into well-crystallized nanopowders. Less studied is the influence of the microwaves on the sol–gel reactions in solutions. The benefit of using microwave-assisted sol–gel preparation highly depends on the reagents used and on the composition of the studied systems. In the present chapter, results on the influence of the microwaves on the chemical reactions that take place during the sol–gel synthesis and on the properties of the resulted samples are discussed.
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"Bio-Mediated Synthesis of Nanomaterials for Packaging Applications". W Materials Research Foundations, 96–117. Materials Research Forum LLC, 2021. http://dx.doi.org/10.21741/9781644901571-4.
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Change in lifestyle of humans in this present generation with huge dependence on packaging materials has encouraged several studies on development of new variety of packaging materials. Emphasis on replacement of existing non-biodegradable packaging materials with biodegradable materials paved the way for the use of biopolymers. Lack of properties, such as thermal stability and mechanical strength in biopolymers led to the development of biopolymer nanocomposites by adding metal/metal oxide nanoparticles as fillers into the biopolymers. Metal/metal oxide nanoparticles improve mechanical/tensile strength, thermal stability as well as antimicrobial properties of the binding and receiving polymer matrix. Bio-mediated synthesis of metal/metal oxide nanoparticles result in the development of novel packaging materials at a low cost and without releasing hazardous wastes into the environments. Novel packaging materials with metal/metal oxide nanoparticles as additives are capable of increasing the shelf life of food, in certain cases they act as indicators of quality food inside the package. Summarily, this present chapter focuses on bio-mediated synthesis of various metal/metal oxide nanoparticles and their applications in food packaging.
Streszczenia konferencji na temat "Non lead oxide"
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Jumpertz, R., D. Muigg, R. Oberhuber, W. Ploss, T. Chatterjee i J. Trogolo. "Voltage Regulator Output Shifts Due to Systematic Oxide Non-Uniformities: Failure Analysis, Layout and Process Solutions". W ISTFA 2004. ASM International, 2004. http://dx.doi.org/10.31399/asm.cp.istfa2004p0512.
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Abstract High volume productions of analog devices require usually more than one production facility. These facilities could be part of the company or in a foundry organization. A smart technology transfer is a key requirement to success. Nevertheless, small deviations of parametric key indices can lead to substantial differences in analog device performance. This paper describes an instructive case study to isolate the root cause of a parametric shift of a low drop output (LDO) voltage regulator. This shift caused a significant yield loss in one of the production facilities. The LDO shift was traced back to a current mirror mismatch. Physical failure analysis shows small differences in the gate oxide thickness which consequently vise versa led to threshold voltage mismatch. Further process analysis identified an unwanted topography in the silicon surface as the root cause of the non-uniform gate oxide growth.
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Min, B. T., H. D. Kim, J. H. Kim, S. W. Hong i I. K. Park. "Particle Size Characteristics of Molten Corium Quenched in Water". W 16th International Conference on Nuclear Engineering. ASMEDC, 2008. http://dx.doi.org/10.1115/icone16-48773.
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During a hypothetical severe accident in a nuclear reactor, a steam explosion might occur when molten corium interacts with water. The strength of a steam explosion affects the integrity of the containment of a nuclear reactor and is highly dependant on the characteristics of the melt-water-steam mixture. Since a break-up and fragmentation process during a pre-mixing are important mechanisms for a steam explosion behavior and affect the debris size distribution, the particle size characteristics of quenched corium have been investigated. For several years, series of experiments have been performed using prototypical corium in the TROI test facility with a high frequency induction heating using cold crucible technology. The molten corium was discharged into the cold water and the quenched debris particles were collected, sieved and examined for the effect of a size distribution on a steam explosion. The small corium droplets do not seem to contribute to a steam explosion owing to solidification at an early stage before the explosion but the large droplets contribute to it owing to their liquid state. It was also shown that single oxides and binary oxides with an eutectic composition (UO2/ZrO2 = 70/30 at weight percentage) led to steam explosions, but a binary oxide with a non-eutectic one did not. The mass mean diameters of the debris of the steam explosive composition was less than that of the non-steam explosive composition. Zirconia was the most energetic steam-explosive material in these tests, and an eutectic composition of corium also lead to a steam explosion, but a non-eutectic composition corium hardly led to a steam explosion. The particle sizes of the molten corium participating in a steam explosion were shown to be mainly 3–6 mm depending on the material and composition.
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Panakarajupally, Ragav P., Joseph Elrassi, K. Manigandan, Yogesh P. Singh i Gregory N. Morscher. "Monitoring Damage in Non-Oxide Composites at High Temperatures Using Carbon-Containing CVD SiC Monofilament Fibers As Embedded Electrical Resistance Sensors". W ASME Turbo Expo 2020: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/gt2020-15937.
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Abstract Electrical resistance has become a technique of interest for monitoring SiC-based ceramic composites. The typical constituents of SiC fiber-reinforced SiC matrix composites, SiC, Si and/or C, are semi-conducive to some degree resulting in the fact that when damage occurs in the form of matrix cracking or fiber breakage, the resistance increases. For aero engine applications, SiC fiber reinforced SiC, sometimes Si-containing, matrix with a BN interphase are often the main constituents. The resistivity of Si and SiC is highly temperature dependent. For high temperature tests, electrical lead attachment must be in a cold region which results in strong temperature effects on baseline measurements of resistance. This can be instructive as to test conditions; however, there is interest in focusing the resistance measurement in the hot section where damage monitoring is desired. The resistivity of C has a milder temperature dependence than that of Si or SiC. In addition, if the C is penetrated by damage, it would result in rapid oxidation of the C, presumably resulting in a change in resistance. One approach considered here is to insert carbon “rods” in the form of CVD SiC monofilaments with a C core to try and better sense change in resistance as it pertains to matrix crack growth in an elevated temperature test condition. The monofilaments were strategically placed in two non-oxide composite systems to understand the sensitivity of ER in damage detection at room temperature as well as elevated temperatures. Two material systems were considered for this study. The first composite system consisted of a Hi-Nicalon woven fibers, a BN interphase and a matrix processed via polymer infiltration and pyrolysis (PIP) which had SCS-6 monofilaments providing the C core. The second composite system was a melt-infiltrated (MI) pre-preg laminate which contained Hi-Nicalon Type S fibers with BN interphases with SCS-Ultra monofilaments providing the C core. The two composite matrix systems represent two extremes in resistance, the PIP matrix being orders of magnitude higher in resistance than the Si-containing pre-preg MI matrix. Single notch tension-tension fatigue tests were performed at 815°C to stimulate crack growth. Acoustic emission (AE) was used along with electrical resistance (ER) to monitor the damage initiation and progression during the test. Post-test microscopy was performed on the fracture specimen to understand the oxidation kinetics and carbon recession length in the monofilaments.
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Zinn, Anthony N., Todd H. Gardner, David A. Berry, Robert E. James i Dushyant Shekhawat. "Investigation of a Novel Reciprocating Compression Reformer for Use in Solid Oxide Fuel Cell Systems". W ASME 2003 1st International Conference on Fuel Cell Science, Engineering and Technology. ASMEDC, 2003. http://dx.doi.org/10.1115/fuelcell2003-1746.
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A novel reciprocating compression device has been investigated as a non-catalytic natural gas reformer for solid oxide fuel cell systems. The reciprocating compression reformer is a potential improvement over current reforming technology for select applications due to its high degree of heat integration, its homogenous gas phase reaction environment, and its ability to co-produce shaft work. Performance modeling of the system was conducted to understand component integration and operational characteristics. The reformer was modeled by utilizing GRI mech. in tandem with CHEMKIN. The fuel cell was modeled as an equilibrium reactor assuming constant fuel utilization. The effect on the reformer and the reformer – fuel cell system efficiencies and exit gas concentrations was examined over a range of relative air-to-fuel ratios, 0.2 to 1.0, and at compression ratios of 50 and 100. Results from this study indicate that the reformer – fuel cell system could approach 50% efficiency, if run at low relative air-to-fuel ratios (0.3 to 0.5). With higher air-to-fuel ratios, system efficiencies were shown to continuously decline due to a decrease in the quality of synthesis gas provided to the fuel cell (i.e. more power being produced by the reformer). Optimal operation of the system has been shown to occur at a relative air-to-fuel ratio of approximately 0.775 and to be nearly independent of the compression ratio in the reciprocating compression reformer. Higher efficiencies may be obtained at lower relative air-to-fuel ratios; however, operation below this point may lead to excessive carbon formation as determined from an equilibrium carbon formation analysis.
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Bertasi, Federico, Marco Bandiera, Alessandro Mancini, Ariana Pavesi, Andrea Bonfanti i Massimiliano Bestetti. "Lab-Scale Anodization of Prototype Brake Calipers". W EuroBrake 2021. FISITA, 2021. http://dx.doi.org/10.46720/3846714eb2021-stp-012.
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Anodization plays a pivotal role in improving the corrosion resistance of Aluminum-Silicon alloys (AlSix) used in the production of brake calipers.[1] However, the presence of eutectic Silicon particles within the Al matrix can reduce the oxide layer growing rate, leading to inhomogeneous and porous coatings. Following this, tailored current/potential anodization waveforms have been developed, in order to overcome the presence of Silicon, thus obtaining anodic layers with enhanced morphological and corrosion-resistance features.[2][3] In this scenario, a fervent lab-scale R&D activity has been carried out regarding the optimization of pulsed anodization in terms of current density and frequency of the used square wave, obtaining: 1) coated AlSix specimens (30cm2) showing a superior corrosion resistance; and 2) a set of refined anodization parameters to be used to treat AlSix –based materials.[4] Unfortunately, anodization of a prototype caliper, using the obtained optimized waveforms, is not straightforward and appears particularly more challenging with respect to the lab-scale treatment of small specimens. Indeed, the presence of: a) non-uniform Silicon distribution (machined vs. non-machined regions); and b) shielded areas and/or sharp edges; can strongly influence the oxide growth, leading to inhomogeneous coatings and a morphology-dependent corrosion resistance. As a further step toward the implementation of the optimized parameters in an anodization pilot plant, an electrochemical bath is designed, aiming at: 1) anodize a single brake caliper; and 2) scale up the anodization parameters from specimens to caliper treatment. The manuscript will discuss the so-obtained anodized caliper in terms of oxide layer: a) morphology; b) wettability; and c) corrosion resistance. The effect of optimized vs. non-optimized parameters will be discussed as well. Results allow to outline the path for an advanced anodization process, that will briefly lead to obtain AlSix brake calipers with an extended corrosion resistance. References: [1] Bandiera, M., Bonfanti, A., Mauri, A., Mancini, A., Bestetti, M., Bertasi, F., “Corrosion Phenomena in Braking Systems”, CORROSION/20, Manuscript no. C2020-14550, 2020. [2] Bandiera, M., Bonfanti, A., Bestetti, M., Bertasi, F., “Anodization: Recent Advancements on Corrosion Protection of Brake Calipers”, SAE Technical Paper, Manuscript no. 2020-01-1626, 2020. [3] Fratila-Apachitei, L. E., J. Duszczyk, and L. Katgerman. "AlSi (Cu) anodic oxide layers formed in H2SO4 at low temperature using different current waveforms", Surface and Coatings Technology, 165.3, pp. 232-240, 2003. [4] Bandiera, M., Mancini, A., Pavesi, A., Bonfanti, A., Bestetti, M., Bertasi, F., “Optimized Pulsed Anodization for Corrosion Protection of Aluminum Silicon Alloys”, CORROSION/21, Manuscript no. C2021-16431, 2021. (under review).
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Shieh, Jay, Szu-Wei Chen i Chia-Yu Fang. "Photocurrent Response of Composite Perovskite Oxide Thin Films With Specific Semiconducting and Ferroelectric Properties". W ASME 2013 Conference on Smart Materials, Adaptive Structures and Intelligent Systems. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/smasis2013-3058.
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The goal of this study is to investigate photocatalytic semiconductor systems which are layered thin film composites built from perovskite oxide materials with characteristics such as small and large band gaps and/or ferroelectricity. In order to improve the efficiency of photocatalysis, semiconductor heterojunctions within the developed composites have been designed to possess electronic band offsets favoring the separation of photo-induced electron and hole (e−/h+) pairs. Furthermore, the remanent polarization of the ferroelectric component within the composites has been utilized to induce favorable band bending at the material interface, lowering the potential barrier for electron transfer. The band offsets and ferroelectric polarization could be considered as built-in electric fields; how they interact with photo-induced e−/h+ would greatly affect the photocatalytic properties of the composites. In this study, various perovskite oxide thin film materials — large band gap strontium titanate (SrTiO3), small band gap silver niobate (AgNbO3) and ferroelectric lead lanthanum titanate (PLT) — were combined to form layered thin film composites. The composites were then adopted as photoanodes in a photoelectrochemical cell and detailed characterization of their photocurrent response was carried out under different light irradiation and ferroelectric polarization conditions. Electronic band offsets at the material interface (i.e., heterojunction) were determined by ultraviolet-visible spectrophotometry and ultraviolet photoelectron spectroscopy. Electric field poling of the ferroelectric component was achieved by non-contact corona charging. Our results have shown that the band offsets at the SrTiO3-AgNbO3 heterojunction were about 1.0 eV in conduction band edge and 0.4 eV in valence band edge, promoting the rapid separation of photo-induced charge carriers; i.e., the flow of e− from SrTiO3 to AgNbO3 and the flow of h+ from AgNbO3 to SrTiO3. It was found that ferroelectric PLT could be used as a seeding layer for the low-temperature (500 °C) growth of SrTiO3/AgNbO3 thin film composites on ITO/glass substrates, forming a layered structure of SrTiO3/AgNbO3/PLT/ITO. In addition, the photocurrent density of the composites could be increased by depositing gold nanoparticles at the PLT-ITO interface. When the polarization of the PLT layer was poled toward the AgNbO3 layer, the potential barrier associated with the flow of e− to the ITO electrode was reduced by favorable band bending created at the AgNbO3-PLT interface. This resulted in a significant increase in photocurrent density.
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Depiak, A., i I. Wierzba. "The Catalytic Oxidation of Heated Lean Homogeneously Premixed Gaseous-Fuel Air Streams". W ASME 2002 Engineering Technology Conference on Energy. ASMEDC, 2002. http://dx.doi.org/10.1115/etce2002/cae-29065.
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Results are presented of an experimental laboratory investigation of the oxidation reactions of heated low velocity streams of homogeneous lean fuel-air mixtures within a packed bed tubular reactor at atmospheric pressure in the presence of non-noble metal oxides catalysts. The main fuel considered was methane, however, other common gaseous fuels, i.e. propane, carbon monoxide, hydrogen and ethylene were also examined for comparative purposes. It was shown that binary cobalt oxide/chromium oxide catalysts can be effective in the oxidation of very lean fuel-air mixtures. Furthermore, there is an optimum value of their mass ratio that could produce a significant improvement to the low temperature oxidation of the lean mixtures examined and the corresponding resulting emissions.
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Zhu, Shengrong, i Sumanta Acharya. "An Experimental Study of Lean Blowout With Hydrogen Enriched Fuels in a Swirl Stabilized Premixed Combustor". W ASME 2011 Turbo Expo: Turbine Technical Conference and Exposition. ASMEDC, 2011. http://dx.doi.org/10.1115/gt2011-46096.
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Lean premixed combustion is widely used to achieve better compromise between nitric oxide (NOx) emissions and combustion efficiency (related to CO levels). However, combustor operation near the lean blowout (LBO) limit can render the flame unstable and lead to oscillations, flashback or extinction, thereby limiting the potential of lean combustion application. Recent interest in integrated gasification combined cycle plants (IGCC) and syngas combustion requires an improved understanding of the role of hydrogen on the combustion process. Therefore, in the present study, combustion of pure methane and blended methane-hydrogen with hydrogen-levels up to 80% by volume has been conducted in a swirl stabilized premixed combustor. Stereo particle image velocimetry (PIV) and OH* chemiluminescence imaging have been used in this study. Results show that there is a single-ringed structure of internal recirculation zone (IRZ) in the non-reacting flow, while in the reacting flows there is a complicated flow pattern with a two-celled IRZ structure in which the axial velocity near the center-axis is oriented downstream. As equivalence ratio decreases, the width of IRZ decreases in methane flames while it increases in hydrogen enriched flames, and the flame shape changes from conical to an elongated columnar shape, especially in hydrogen enriched flames. There are two different modes of vortex breakdown observed, spiral mode in methane flames and bubble mode in hydrogen enriched flames. The mechanisms of LBO in pure methane and hydrogen enriched premixed flames are shown to be different and explained in the present study.
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Cheney, J., i G. Kusinski. "Performance of Corrosion Resistant Arc Spray Coatings as a Function of Spray Parameters". W ITSC 2012, redaktorzy R. S. Lima, A. Agarwal, M. M. Hyland, Y. C. Lau, C. J. Li, A. McDonald i F. L. Toma. ASM International, 2012. http://dx.doi.org/10.31399/asm.cp.itsc2012p0550.
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Abstract Twin wire arc spray (TWAS) coatings were produced under varying spray conditions (spray angle, traverse rate, and spray distance) to simulate on-site hand spraying operations typically used to coat existing refinery vessels. Two materials, Alloy C276 (commonly used for corrosion protection of refinery vessels) and the newly developed Nicko-Shield 200 chemistry (designed to reduce porosity and oxide content under arc spray conditions) were compared in the testing. Alloy C276 coatings showed good coating performance (>40 MPa adhesion) when sprayed under ideal conditions, but showed a sharp drop off in coating integrity (<20 MPa adhesion) when sprayed at lower traverse rates, sharper angles, and closer spray distances. Deviating from non-ideal conditions resulted in increased porosity and oxide content leading to increased permeability. It was concluded that non-ideal conditions, which intermittently occur in hand spraying operations on large surface areas, can lead to coating patches with unacceptably low adhesion, potential spalling, and high permeability when spraying Alloy C276. Patches of low coating quality require additional maintenance or result in coating failure, creating a lack of confidence in thermal spray technology as a protective solution in the industry. This study shows the results of an effort to develop an alloy solution which is more reliable in spraying large surface areas by hand for corrosion protection. The developed Ni-based material showed improved adhesion (70+ MPa) and greatly reduced permeability (as measured by ferroxyl exposure). This performance was stable across the wide range of spray conditions used in this study. This suggests that alloy design can be used to increase the reliability for twin wire arc spray coatings, and enable confidence for expanded use in this industry.
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Kumar, Naveen, Harveer Singh Pali i Sidharth Bansal. "Some Studies on NOX Reduction From a Diesel Engine Using Stabilized Emulsion". W ASME 2018 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/imece2018-87374.
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The twentieth century has seen a rapid twenty-fold increase in the use of fossil fuels. Personal and commercial transportation consumes 2% of the total world energy. The main products of combustion of fossil fuel are carbon mono oxide (CO), unburned hydrocarbons (HC), Carbon dioxide (CO2), oxides of sulfur (SOx), oxides of nitrogen (NOx) and particulate matter. Oxides of nitrogen (NOx) are the major diesel engine pollutants and referred to as mixtures of nitric oxide (NO) and nitrogen dioxide (NO2). NOx emissions are required to be controlled because NO and NO2 contribute to the formation of smog, an environmental and human health hazard. NO2 is also directly of concern as a human lung aggravation. To reduce NOx emissions from a diesel engine, the introduction of water in the combustion chamber of a diesel engine is a promising option as vaporization of water reduces adiabatic flame temperature and micro-explosion phenomena lead to improved mixing. In the present study, stable D/W emulsion, with varying water content, up to 3% were prepared using span 80 as a surfactant. The results indicated a reduction in NOx and smoke with increasing water volume fraction in the emulsion compared to diesel baseline. However, beyond 2% water content led to increased ignition delay and higher diffusion phase heat release resulting in noisy engine operation. Therefore, it can be concluded that diesel-water emulsion with 2% water could be used for significant reduction of NOx emissions from diesel and biodiesel operation of a CI Engine.
Raporty organizacyjne na temat "Non lead oxide"
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Panek. PR-312-12208-R01 Plume Volume Molar Ratio Method Assumptions and Conservative Model Over-Predictions. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), kwiecień 2013. http://dx.doi.org/10.55274/r0010806.
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With the introduction of the more stringent short-term 1-hour air quality NO2 standard, the use of redundant, overly conservative assumptions (e.g. use of permit allowable emissions � hourly rate based on maximum annual tons per year) is no longer appropriate and potentially misinforms and obfuscates modeling compliance demonstrations. One of the challenges of modeling oxides of nitrogen (NOx) emissions is determining the amount of total NOx that will exist in the form of nitrogen dioxide (NO2) at a receptor. Combustion source emissions usually contain mostly nitric oxide (NO), which is not a regulated criteria pollutant. The Plume Volume Molar Ratio Method (PVMRM) is a higher fidelity �Tier 3� model option contained within the USEPA AERMOD dispersion model for the purpose of reducing the inherent conservatism associated with predicting the NO2 fraction within a plume. Tier 3 approaches must be approved on a case-by-case basis by the regulatory agency prior to approval. The American Petroleum Association (API), Council of Industrial Boiler Owners (CIBO), Electric Power Research Institute (EPRI), AF and PA (American Forest and Paper Association) and other trade associations and stakeholders have undertaken initial investigatory efforts into the Plume Volume Molar Ratio Method (PVMRM) algorithm and model chemistry formulation. The initial results of this work were presented at the EPA 10th Modeling Conference on March 13th through 15th, 2012. Section 320 of the Clean Air Act (CAA) requires a conference to be held every 3 years. The purpose of the conference is to provide an overview of the latest features of the agency�s preferred air quality models and to provide a forum for public review and comment on how the agency determines and applies air quality models in the future. This report provides a technical description of the current state of the Plume Volume Molar Ratio Method (PVMRM) currently used by EPA in the AERMOD model and the Air Quality Modeling Guidance contained in Appendix W. This paper examines the conservative assumptions used by EPA that lead to conservative model over-predictions, work that was recently presented at the 10th Modeling Conference on PVMRM, and gaps and shortcomings for existing reciprocating compressors. This report also summarizes the initial findings from these efforts and identifies potential gaps (e.g. shorter stacks and lower in-stack NO/NO2 ratios) in the analysis as it may relate to existing reciprocating engine drivers.
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Nowlin, Jacob, Kevin Wallace, Kyle Beurlot, Mark Patterson i Timothy Jacobs. PR-457-21206-R01 CFD Study of Prechamber NOx Production Mechanisms. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), lipiec 2023. http://dx.doi.org/10.55274/r0000027.
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Use of the pre-combustion chamber (PCC) as an ignition source in large-bore natural gas engines has shown promise in reducing emissions. By increasing the ignition energy and surface area via a turbulent jet, these devices can extend the lean operating limit of the engine and reduce oxides of nitrogen (NOx). This study aims to characterize the sensitivity of main chamber NOx formation to changes in the PCC jet. A CFD model of a Cooper-Bessemer GMV two-stroke lean-burn natural gas engine is used for this purpose. The temperature and chemical composition of the PCC jet are varied across several tasks, and the resulting changes in main chamber NO and shy;x emissions are recorded. Three-dimensional plotting tools are used to determine where and when NOx forms in the engine during the cycle. Data on the chemical pathways to NO and NO2 and shy; and shy; formation and destruction is also presented.
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Adair, Carol, Heather Darby, Tyler Goeschel, Lindsay Barbieri i Alissa White. Evaluating Greenhouse Gas Emissions in Promising Tillage and Manure Application Practices at Borderview Farm. USDA Northeast Climate Hub, lipiec 2017. http://dx.doi.org/10.32747/2017.6957453.ch.
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A research team at UVM, led by Dr. Carol Adair and Dr. Heather Darby, is evaluating the benefits and drawbacks of four different tillage approaches (conventional, strip, vertical, and no till) and two different methods of manure application (broadcast and injection). The goal is to determine the practices best suited for reducing greenhouse gas emission, improving carbon storage and limiting nitrogen losses. The team measures carbon dioxide and nitrous oxide emissions from the treatments every two weeks or more frequently after events (large rainfall, manure application) using a measuring device called photoacoustic multigas monitor.
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McHale, Yalin i Olsen. PR-179-13203-R01 Real Time Laser Sensor for Nitrogen Oxides and Carbon Monoxide. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), sierpień 2014. http://dx.doi.org/10.55274/r0010020.
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Performance of current NOx sensors is problematic, in particular drift and cross-sensitivity to other species. Many lean burn engines are operated based on earlier calibrations. Operators must allow for drift and use large margins to meet emissions. Laser sensors (based on absorption at target wavelengths) are self-calibrating and immune to interferences. In particular, recently developed Quantum Cascade Lasers (QCLs) allow measurements at mid-infrared (MIR) wavelengths thereby allowing stronger signals, better schemes to mitigate interferences, and fast time response. This project evaluated a commercial QCL-based NOx (NO, NO2) and CO sensor for use in gas engine applications. The project also developed and performed bench top testing of a custom sensor which uses a �pitch and catch� design.
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Reynolds, John G., Paul R. Coronado i Lucy H. Hair. Reduction of Nitrogen Oxide Emission for Lean Burn Engine Technology Final Report CRADA No. TC-315-92C. Office of Scientific and Technical Information (OSTI), marzec 2018. http://dx.doi.org/10.2172/1431003.
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Reynolds, J., i M. Royce. Reduction of Nitrogen Oxide Emission for Lean-Burn Engine Technology Final Report CRADA No. TC-0315-92-C. Office of Scientific and Technical Information (OSTI), luty 2018. http://dx.doi.org/10.2172/1424679.
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Chapman i Toema. PR-266-07209-R01 Phase 2 - Assessment of the Robustness and Transportability of the Gas Turbine Model. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), grudzień 2010. http://dx.doi.org/10.55274/r0010719.
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This report presents the modeling study of a gas turbine combustor based on first engineering principles to fully characterize the nitrogen oxides (NOx) and carbon monoxide emissions (CO). The model is mainly focused on the emissions from the widely used lean-premixed, dry low-NOx combustor. The combustor is divided into several zones where each zone can be considered as a plug-flow reactor. Each of these zones is assumed to have a uniform pressure, temperature and perfect mixing between combustion species. The temperature of each zone is calculated using mass and energy balances along with heat transfer through the combustor liner. The emissions are calculated using well-know pollutant reaction schemes such as the Zeldovich mechanism in addition to other well-established semi-empirical correlations.
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GARDNER, TIMOTHY J., LINDA I. MCLAUGHLIN, DEBORAH L. MOWERY i RONALD S. SANDOVAL. Preparation Effects on the Performance of Silica-Doped Hydrous Titanium Oxide (HTO:Si)-Supported Pt Catalysts for Lean-Burn NOx Reduction by Hydrocarbons. Office of Scientific and Technical Information (OSTI), styczeń 2002. http://dx.doi.org/10.2172/793222.
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Willson. L51709 Development-Test Electronic Gas Admission for Large Bore Engines. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), sierpień 1994. http://dx.doi.org/10.55274/r0010114.
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The pipeline industry uses over 8,000 large bore engines in gas transmission/compression service". These engines are typically gas fueled and spark ignited. Some early versions of the engines are piston scavenged, but most are turbocharged. Some models, especially those equipped for lean burn operation, utilize pre-combustion chambers for enhanced ignition. Typically, the gaseous fuel is admitted directly into the top of the engine combustion chamber by a cam-operated, mechanical gas admission valve (MGAV). The MGAV is operated by an engine driven cam, cam follower, push rod, and rocker assembly. Such mechanisms offer little in the way of adjustability of the gas admission event: the ability to change the start of gas admission (SOA) and end of gas admission (EOA). The gas admission system is generally optimized for a particular mode of engine operation, typically rated speed and full load, and is fixed in that state. Desired changes in the gas admission cycle are not easily accomplished. At the same time, however, undesired changes commonly occur due to wear, failure, and mis-adjustment of the MGAV drive train. This report documents the development of a natural gas-fueled large-bore engine test bed (LBET) at Colorado State University and the subsequent test of an electronic gas admissions valve (EGAV) with in-cylinder pressure feedback. The LBET is now a state-of-the-art natural gas-fueled test facility. It will be open for use in late 1994 or early 1995 to all parties interested in testing equipment that might lead to safer, more economical and cleaner burning gas fueled engines. The EGAV tests were successful. The valve allows for precise control of fuel admission and end of admission timing. This results in the engine running in a real-time balance condition. Laboratory tests showed a 30% reduction of hydrocarbons and nitrous oxides reductions with a 2% reduction in fuel consumption. Field testing will continue in 1995 prior to commercialization.
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Gattoni i Olsen. PR-179-10211-R01 Advanced Control Techniques and Sensors for Gas Engines with NSCR. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), lipiec 2012. http://dx.doi.org/10.55274/r0010987.
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High exhaust emissions reduction efficiencies from a spark ignited (SI) internal combustion engine utilizing an NSCR catalyst system requires complex fuel control strategies. The allowable equivalence ratio operating range is very narrow where NSCR systems achieve high exhaust emissions reduction efficiencies of multiple species. Current fuel control technologies utilizing lambda sensor feedback are reported to be unable to sustain these demands for extended operation periods and when transients are introduced. Lambda sensor accuracy is the critical issue with current fuel controllers. The goal of this project was to develop a minimization control algorithm utilizing a Nitrogen Oxide (NOx) sensor installed downstream of the NSCR catalyst system for feedback air/fuel ratio control. When the engine is operated lean, NOx is produced and the NOx sensor responds accordingly. When the engine is operated rich, the NSCR catalyst system produces Ammonia. The NOx sensor has a cross sensitivity to Ammonia and responds as though it has been exposed to NOx. This behavior provides an opportunity for a unique control strategy that allows lambda sensor calibration to be ignored. Testing was performed on a 100kW rated Cummins-Onan generator set that was reconfigured to operate utilizing an electronic gas carburetor (EGC2) with lambda sensor feedback and high reduction efficiency NSCR catalyst system. The control algorithm was programmed utilizing a Labview interface that communicated with the electronic gas carburetor where the fuel trim adjustment was physically made. Improvement under steady state operation was observed. The system was also evaluated during load and fuel composition transients.