Academic literature on the topic 'Methane number'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the lists of relevant articles, books, theses, conference reports, and other scholarly sources on the topic 'Methane number.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Journal articles on the topic "Methane number"
1
Blankenship, Andrea N., Manoj Ravi, and Jeroen A. van Bokhoven. "Esterification Product Protection Strategies for Direct and Selective Methane Conversion." CHIMIA International Journal for Chemistry 75, no. 4 (April 28, 2021): 305–10. http://dx.doi.org/10.2533/chimia.2021.305.
Full textAbstract:
A scale-flexible process for the direct and selective oxidation of methane to primary oxygenates is of great interest, however, a commercially feasible approach has yet to be realized due to a number of challenges. Low product yields imposed by a well-established selectivity-conversion limit are particularly burdensome for direct methane-to-methanol chemistry. One strategy that has emerged to break out of this limit is the in situ esterification of produced methanol to the more oxidation-resistant methyl ester. However, these methaneto-methyl-ester approaches still elude commercialization despite their unprecedented high yields. Herein, we outline some of the key barriers that hinder the commercial prospects of this otherwise promising route for highyield direct catalytic methane conversion, including extremely corrosive reagents, homogeneous catalysts, and inviable oxidants. We then highlight directions to address these challenges while maintaining the characteristic high performance of these systems. These discussions support the efficacy of product protection strategies for the direct, selective oxidation of methane and encourage future work in developing creative solutions to merge this promising chemistry with more practical industrial requirements.
2
Yudiandika, I. Putu, I. Wayan Suarna, and I. Made Sudarma. "PENGARUH JUMLAH BAKTERI METHANOBACTERIUM DAN LAMA FERMENTASI TERHADAP PROPORSI GAS METANA (CH4) PADA PENGOLAHAN SAMPAH ORGANIK DI TPA SUWUNG DENPASAR." ECOTROPHIC : Jurnal Ilmu Lingkungan (Journal of Environmental Science) 11, no. 1 (May 1, 2017): 29. http://dx.doi.org/10.24843/ejes.2017.v11.i01.p05.
Full textAbstract:
EFFECT OF NUMBER OF METHANOBACTERIUM AND FERMENTATION DURATION TO METHANE (CH4) GAS PROPORTION IN ORGANIC WASTE PROCESSING IN SUWUNG TPA DENPASARA research has been conducted to find out the effect to the amount of methanobacterium bacteria and fermentation duration toward proportion of methana (CH4) at organic waste processing at TPA Suwung Denpasar. Methana gas produced from this organic waste will be processed become fuel of electric generation. From this study will be expected to get all methana gas that contained at the waste so that there is no methana gas loss to the atmosphere. This study was conducted by using 4 treatments that are without bacteria (B0), bacteria with number of population 106 CFU/ml (B1), bacteria with population of 107 CFU/ml (B2), and bacteria with population of 108 CFU/ml (B3). Each treatment conducted thrice (3) repeat. The four treatments conducted measurement of gas variable after fermentation during 0 week, 3 weeks, 5 weeks, 7 weeks and 9 weeks by uisng gas analyzer GA 2000 Geotech. Data from study result then analyzed by using complicated factorial design (RAL). From ANOVA analysis shows there was significant bacteria number and fermentation duration toward proportion or procentage of methana gas resulted. The longer fermentation time takes place, the bigger the proportion of the methane gas produced. However, the greater number of the bacteria population does not always produce bigger proportion of methane gas To find out the combination which could give best effect the researcher used Duncan test. The result of analysis from Duncan shows that combination at the ninth weeks by number of bacteria 107 CFU/ml giving best result that was percentage of methana gas is 55,10%.
3
Malenshek, Martin, and Daniel B. Olsen. "Methane number testing of alternative gaseous fuels." Fuel 88, no. 4 (April 2009): 650–56. http://dx.doi.org/10.1016/j.fuel.2008.08.020.
Full text
4
Ryan, T. W., T. J. Callahan, and S. R. King. "Engine Knock Rating of Natural Gases—Methane Number." Journal of Engineering for Gas Turbines and Power 115, no. 4 (October 1, 1993): 769–76. http://dx.doi.org/10.1115/1.2906773.
Full textAbstract:
A procedure has been developed and documented for determining the methane number of gaseous fuels. The methane number provides an indication of the knock tendency of the fuel. An experimental test matrix was designed for quantifying the effects of ethane, propane, butane, and CO2. A unique gas mixing and control system was developed to supply test gases to the engine and to control the equivalence ratio and engine operation. The results of the experiments agreed well with the limited data published in the literature. Predictive equations were developed for the methane number (MN) of gaseous fuels using the gas composition. The forms of these equations are suitable for incorporation in a computer program or a spreadsheet.
5
Kussmaul, Martin, Markus Wilimzig, and Eberhard Bock. "Methanotrophs and Methanogens in Masonry." Applied and Environmental Microbiology 64, no. 11 (November 1, 1998): 4530–32. http://dx.doi.org/10.1128/aem.64.11.4530-4532.1998.
Full textAbstract:
ABSTRACT Methanotrophs were present in 48 of 225 stone samples which were removed from 19 historical buildings in Germany and Italy. The average cell number of methanotrophs was 20 CFU per g of stone, and their activities ranged between 11 and 42 pmol of CH4 g of stone−1 day−1. Twelve strains of methane-oxidizing bacteria were isolated. They belonged to the type II methanotrophs of the genera Methylocystis,Methylosinus, and Methylobacterium. In masonry, growth substrates like methane or methanol are available in very low concentrations. To determine if methane could be produced by the stone at rates sufficient to support growth of methanotrophs, methane production by stone samples under nonoxic conditions was examined. Methane production of 0.07 to 215 nmol of CH4 g of stone−1 day−1 was detected in 23 of 47 stone samples examined. This indicated the presence of the so-called “mini-methane”-producing bacteria and/or methanogenic archaea. Methanotrophs occurred in nearly all samples which showed methane production. This finding indicated that methanotrophs depend on biogenic methane production in or on stone surfaces of historical buildings.
6
Kuczyński, Szymon, Mariusz Łaciak, Adam Szurlej, and Tomasz Włodek. "Impact of Liquefied Natural Gas Composition Changes on Methane Number as a Fuel Quality Requirement." Energies 13, no. 19 (September 26, 2020): 5060. http://dx.doi.org/10.3390/en13195060.
Full textAbstract:
The one of main quality requirements of natural gas as an engine fuel is the methane number (MN). This parameter indicates the fuel’s capability to avoid knocking in the engine. A higher MN value indicates a better natural gas quality for gas engines. Natural gas with higher methane content tends to have higher MN value. This study presents analysis of deviation of liquefied natural gas (LNG) composition and its impact on LNG quality as an engine fuel. The analysis of higher hydrocarbons and nitrogen content impact on LNG parameters was considered for several samples of LNG compositions. Most engine manufacturers want to set a new, lower limit value for methane number at 80. This fact causes significant restrictions on the range of variability in the composition of liquefied natural gas. The goal of this study was to determine the combination of the limit content of individual components in liquefied natural gas to achieve the strict methane number criterion (MN > 80). To fulfill this criterion, the methane content in LNG would have to exceed 93.7%mol, and a significant part of the LNG available on the market does not meet these requirements. The analysis also indicated that the methane number cannot be the only qualitative criterion, as its variability depends strongly on the LNG composition. To determine the applicability of LNG as an engine fuel, the simultaneous application of the methane number and Wobbe index criteria was proposed.
7
Islam, Tajul, Maqsud Hossain, Naushin Tabassum, Mahir Amer Haque, Hasan Mahmud Reza, and Lise Øvreås. "Two Novel Thermotolerant Methane Oxidizers from a Tropical Natural Gas Field in Bangladesh." Bangladesh Journal of Microbiology 38, no. 2 (February 6, 2022): 63–71. http://dx.doi.org/10.3329/bjm.v38i2.58104.
Full textAbstract:
Aerobic thermotolerant methane oxidizers utilize methane as a sole carbon and energy source, and predominantly they are associated with the phylum Proteobacteria. Here we present two further new strains (HGS-45: coccusshaped and HGF-47: rod-shaped and vibrioid) of thermotolerant obligate proteobacterial methanotrophic bacteria, which were isolated from an abandoned tropical natural gas field wet soil sample in the northeast of Bangladesh. Strains are Gram-negative, nonmotile, and capable of growth on methane and methanol as their energy sources. Isolates are thermotolerant and could grow up to 52oC, optimally at 42oC, but show no growth at 55 or 15oC. Based on 16S rRNA gene sequence analyses and phylogenetically, HGS-45 is most closely related to the obligate Type Ib methanotroph Methylococcus capsulatus of the family Methylococcaceae, whereas HGF-47 is affiliated to Type IIa methanotroph Methylocystis sp. of the family Methylocystaceae and possesses Type II intracytoplasmic membrane (ICM) systems. Genes of particulate methane monooxygenase (pMMO) and the methanol dehydrogenase (MDH) were detected by PCR. Southern-blot analyses of genomic DNA from both strains were positive, implying the aerobic biological oxidation process from methane to methanol by the pMMO. Each strain presumably represents a novel species. Furthermore, both strains will increase our knowledge of thermotolerant methanotrophic proteobacterial diversity, cohabitation, and their participation to global carbon cycles as well as signifying biological methane sinks in the terrestrial natural gas field ecosystems. Bangladesh J Microbiol, Volume 38, Number 2, December 2021, pp 63-71
8
Inagaki, Fumio, Urumu Tsunogai, Masae Suzuki, Ayako Kosaka, Hideaki Machiyama, Ken Takai, Takuro Nunoura, Kenneth H. Nealson, and Koki Horikoshi. "Characterization of C1-Metabolizing Prokaryotic Communities in Methane Seep Habitats at the Kuroshima Knoll, Southern Ryukyu Arc, by Analyzing pmoA, mmoX, mxaF, mcrA, and 16S rRNA Genes." Applied and Environmental Microbiology 70, no. 12 (December 2004): 7445–55. http://dx.doi.org/10.1128/aem.70.12.7445-7455.2004.
Full textAbstract:
ABSTRACT Samples from three submerged sites (MC, a core obtained in the methane seep area; MR, a reference core obtained at a distance from the methane seep; and HC, a gas-bubbling carbonate sample) at the Kuroshima Knoll in the southern Ryuku arc were analyzed to gain insight into the organisms present and the processes involved in this oxic-anoxic methane seep environment. 16S rRNA gene analyses by quantitative real-time PCR and clone library sequencing revealed that the MC core sediments contained abundant archaea (∼34% of the total prokaryotes), including both mesophilic methanogens related to the genus Methanolobus and ANME-2 members of the Methanosarcinales, as well as members of the δ-Proteobacteria, suggesting that both anaerobic methane oxidation and methanogenesis occurred at this site. In addition, several functional genes connected with methane metabolism were analyzed by quantitative competitive-PCR, including the genes encoding particulate methane monooxygenase (pmoA), soluble methane monooxygenase (mmoX), methanol dehydrogenese (mxaF), and methyl coenzyme M reductase (mcrA). In the MC core sediments, the most abundant gene was mcrA (2.5 × 106 copies/g [wet weight]), while the pmoA gene of the type I methanotrophs (5.9 × 106 copies/g [wet weight]) was most abundant at the surface of the MC core. These results indicate that there is a very complex environment in which methane production, anaerobic methane oxidation, and aerobic methane oxidation all occur in close proximity. The HC carbonate site was rich in γ-Proteobacteria and had a high copy number of mxaF (7.1 × 106 copies/g [wet weight]) and a much lower copy number of the pmoA gene (3.2 × 102 copies/g [wet weight]). The mmoX gene was never detected. In contrast, the reference core contained familiar sequences of marine sedimentary archaeal and bacterial groups but not groups specific to C1 metabolism. Geochemical characterization of the amounts and isotopic composition of pore water methane and sulfate strongly supported the notion that in this zone both aerobic methane oxidation and anaerobic methane oxidation, as well as methanogenesis, occur.
9
Dec, Steven F., Kristin E. Bowler, Laura L. Stadterman, Carolyn A. Koh, and E. Dendy Sloan. "Direct Measure of the Hydration Number of Aqueous Methane." Journal of the American Chemical Society 128, no. 2 (January 2006): 414–15. http://dx.doi.org/10.1021/ja055283f.
Full text
10
Tjojudo, Danianto Hendragiri, and Sutrasno Kartohardjono. "Methane Number Improvement of Gas from LNG Regasification Unit." E3S Web of Conferences 67 (2018): 04033. http://dx.doi.org/10.1051/e3sconf/20186704033.
Full textAbstract:
Methane Number (MN) is one of quality requirement of gas as fuel for gas engine, which indicates fuel capability to avoid knocking in the engine. Higher MN provides better quality of gas for gas engine. Natural gas with higher methane (CH4) and fewer higher hydrocarbon, tends to have higher MN score. This study aims to obtain heating methods of LNG to produce vapor that has appropriate MN as a fuel gas supply to gas engine. The simulation for LNG regasification prepared is an approach to the design of the existing regasification facility of the power plant in Bali. The temperature ranges for LNG heating simulation were obtained based on saturated temperatures of LNG phase envelopes. In the simulation. to obtain a certain MN value can be conducted by adjusting the temperatures at two different values i.e. above -110 ° and below - 80 °. To produce LNG vapor that has MN of 80 either through higher temperature of heating (HT heating) or lower temperature of heating (LT heating) requires more energy than direct heating without MN improvement. Heat loading for LT heating is higher than HT heating due to more temperature defference between LT and heating fluid temperatures. The ability of engine to produce power decreased with decreasing fuel gas MN. The power increment increases for lower MN gas if MN improvement is conducted.
Dissertations / Theses on the topic "Methane number"
1
Хамза, Омар Адел Хамза. "Вибір параметрів силової установки із системою утилізації попутного нафтового газу." Thesis, НТУ "ХПІ", 2017. http://repository.kpi.kharkov.ua/handle/KhPI-Press/29868.
Full textAbstract:
Дисертація на здобуття наукового ступеня кандидата технічних наук за спе-ціальністю 05.05.03 – двигуни та енергетичні установки. – Національний технічний університет «Харківський політехнічний інститут». – Харків, 2017. Дисертаційна робота присвячена вибору схеми та параметрів силової енергетичної установки для утилізації попутного нафтового газу. В роботі проаналізовано можливість використання різних силових установок для утилізації попутного нафтового газу. Розроблено схеми енергогенеруючих установок з використанням газо-турбінних і газопоршневих двигунів внутрішнього згоряння для виробництва еле-ктричної енергії за рахунок утилізації попутного нафтового газу на нафтовидобувних і нафтопереробних підприємств. Використано енергоексергетичний метод для оцінки ефективності запропонованих схем. Проведено економічний аналіз доцільності побудови енергогенеруючих потужностей, що будуть споживати попутний нафтовий газ з аналізом чутливості для таких параметрів як зміна ціни на електроенергію та вплив високих температур навколишнього середовища. При зміні температури навколишнього середовища з +15 до +45 °С кількість енергії, що виробляється для проекту А буде зменшуватися на 26%, для проекту В – на 10,9%. Визначено, що попри більшу вартість проекту В ($2 843 009.55) супроти проекту А ($1 964 434.69), термін окупності складає: для проекту А – 6 років, 1 місяць; для проекту В – 3 роки, 8 місяців. Обґрунтована доцільність використання поршневого ДВЗ у складі енергогенеруючої установки.Thesis for the degree of candidate of technical sciences by specialty 05.05.03 - engines and power units. - National Technical University "Kharkiv Polytechnic Institute". - Kharkiv, 2017. The thesis is devoted to the choice of the scheme and parameters of the power plant for utilization of associated petroleum gas. The paper analyzes the possibility of using various power plants for utilization of associated petroleum gas. The schemes of power units using gas turbine and gas piston internal combustion engines to generate power electricity have been developed by using associated petroleum gas in oil refinery. The anergy-exergy method was used to analys the effectiveness of the proposed schemes. An economic analysis of the feasibility of constructing power generating capacities that will consume the associated oil gas with an analysis of sensitivity for such parameters as a change in the price of electricity and the impact of high ambient temperatures has been carried out. If the ambient temperature is changed from +15 to + 45 ° C, the amount of energy generated for Project A will be reduced by 26%, for Project B - by 10.9%. It is determined that despite the high cost of Project B ($ 2,843,009.55) against Project A ($ 1964,434.69), the payback period is: for Project A - 6 years, 1 month; For Project B - 3 years, 8 months. The expediency of using the piston-internal ICE as part of the power generating unit is substantiated.
2
Hamzah, Omar Adel Hamzah. "Parameter selection the powerplant with recovery system Off-gas in the refinery." Thesis, NTU "KhPI", 2017. http://repository.kpi.kharkov.ua/handle/KhPI-Press/29869.
Full textAbstract:
Dissertation for the candidate degree in specialty 05.05.03 "Engines and Power Plants". - National Technical University "Kharkiv Polytechnic Institute ", Kharkiv 2017. The thesis is devoted to actual problem - the selection of schemes and power parameters of the power plant for utilization of associated gas. The problem of associated gas flaring continuously rising international conferences on conservation of the environment are held under the auspices of the UN and the World Bank. In particular, the World Conference on Climate in Paris (COP21) in 2015, and was nominated Global Initiatives to eradicate the practice of flaring of associated gas in the oil industry. Worldwide, it was supported by 45 oil companies, governments and other parties through which CO2 emissions can be reduced by 100 million tons per year. The adopted program "Zero Routine Flaring by 2030" provides end to the practice of burning of associated gas by 2030. This Initiatives supported and Iraq, which in 2015 take the second place in the world with the burning of associated gas in flares. Associated petroleum gas is 2% of product yield refineries in Iraq. Given the number of refineries and their power daily when they are flaring loss a lot of energy and is a significant pollution of the territory not only as chemical emissions but as a heat is released during the combustion of associated gas. The work uses a comprehensive approach to the selection circuit and power parameters power plant for utilization of associated gas. The possible options for the utilization of associated gas. According to the options two power plants are taken the first one based on gas turbine engine and the second based on gas turbine engine and a piston engine. The question examined in terms of exergic-anergy balance installation and obtain the best technical and economic performance, taking into account the climatic characteristics of Iraq The features of physical and chemical composition of associated petroleum gas in the refinery in Iraq, in particular methane determined the number, the method of firm Caterpillar. The methane number of the gas fuel affects the choice piston power plant. Significant impact on the choice of installing recycling schemes associated gas temperature features render the region. For their consideration set average temperature for the region. Conducted thermal calculations allowed to analyze the impact of environmental temperature on performance of power plants and conduct a feasibility study best selection circuit installation. Implementation exergic-anergy balance for power plants proposed scheme has allowed to confirm significant reduction in thermal pollution and show the most attractive from that perspective scheme. Economic calculations allowed to determine the payback period of the projects and installations prove the economic feasibility of their construction. The most economically attractive project. The analysis of the economic risks of sensitivity to changes in prices of electricity and to changes in ambient temperature. Similar calculations of sensitivity analysis performed for the two plants power plants. Based on the analysis, commissioned by the Iraqi side was developed based business project for energy generation capacity on the basis of energy utilization units. The results of the study will not only get the necessary electrical energy that can be used not only in the enterprise, but also to improve the environment in accordance with international agreements. The results of the research will be used in the construction of new units in the refineries in Iraq according to a letter from the Ministry of Industry and minerals.Дисертація на здобуття наукового ступеня кандидата технічних наук за спеціальністю 05.05.03 «Двигуни та енергетичні установки» (14 – Електрична інженерія). – Національний технічний університет «Харківський політехнічний інститут», Харків, 2017. Дисертаційна робота присвячена актуальному питанню - вибору схеми та параметрів силової енергетичної установки для утилізації попутного нафтового газу. Проблема спалювання попутних газів постійно підіймається на міжнародних конференціях зі збереження навколишнього середовища які проходять під егідою ООН та Всесвітнього банку. Зокрема, на Всесвітній конференції з клімату в Парижі (COP21) у 2015 році, була висунута та підтримана глобальна ініціатива з викорінення практики спалювання попутного газу в нафтовій промисловості. В усьому світі її підтримали 45 нафтових компаній, урядів та інших сторін завдяки яким викиди CO2 можуть скоротитись на 100 мільйонів тонн на рік. Прийнята програма “Zero Routine Flaring by 2030” передбачає покінчити з практикою спалювання супутнього нафтового газу до 2030 року. Цю ініціативу підтримала і держава Ірак, яка на 2015 рік займала друге місце у світі зі спалювання попутних газів у факелах. Попутний нафтовий газ складає 2% від виходу продуктів нафтопереробного підприємства в Іраку. Враховуючи кількість нафтопереробних підприємств та їх потужності, щоденно, при його спалюванні у факелах, втрачається велика кількість енергії та відбувається значне забруднення навколишньої території не тільки хімічними викидами а і теплотою яка виділяється при згорянні попутного нафтового газу. У роботі використано комплексний підхід до вибору схеми та параметрів силової енергетичної установки для утилізації попутного нафтового газу. Розглянуто можливі варіанти утилізації супутнього нафтового газу. Серед варіантів взято енергетичну установку на базі газотурбінного двигуна та установку на базі газотурбінного двигуна який діє сумісно з поршневим двигуном. Поставлене питання розглянуто з точки зору енерго-ексергетичного балансу установки та отримання найкращих техніко-економічних показників з урахуванням кліматичних особливостей регіону держави Ірак. Розглянуто особливості фізико-хімічного складу супутнього нафтового газу на нафтопереробному заводі держави Ірак, зокрема проведено визначення метанового числа, за методикою фірми Caterpillar. Метанове число газового палива впливає на вибір поршневої енергетичної установки. Значний вплив на вибір схеми установки з утилізації супутнього нафтового газу оказують температурні особливості регіону. Для їх урахування визначено середню температуру для регіону. Проведені теплові розрахунки дозволили проаналізувати вплив температури навколишнього середовища на показники енергетичних установок та провести економічне обґрунтування обрання найкращої схеми установки. Виконання енерго-ексергетичного балансу для запропонованих схем енергогенеруючих установок дозволило підтвердити значне зменшення теплового забруднення навколишнього середовища та вказати на найбільш привабливу з цієї точки зору схему. Економічні розрахунки дозволили визначити термін окупності запропонованих проектів установок та довести економічну доцільність їх побудови. Визначено найбільш економічно привабливий проект. Проведено аналіз економічних ризиків чутливості до зміни ціни електроенергії та до зміни температури навколишнього середовища. Подібні розрахунки аналізу чутливості проведено для заводів з двома енергетичними установками. На основі проведеного аналізу, на замовлення Іракської сторони, було розроблено основу бізнес проекту для енергогенеруючих потужностей на базі енергетичних утилізаційних установок. Виконання результатів дослідження дозволить не тільки отримати необхідну електричну енергію, яку можна використовувати не тільки на підприємстві, а і покращити стан навколишнього середовища у відповідності до міжнародних домовленостей. Результати дисертаційного дослідження будуть використані при будівництві нових енергоблоків на нафтопереробних заводах Іраку згідно листа від Міністерства промисловості і природних ресурсів.
3
Shi, Lingsheng. "Numbers and topologies." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät II, 2003. http://dx.doi.org/10.18452/14871.
Full textAbstract:
In der Ramsey Theorie fuer Graphen haben Burr und Erdos vor nunmehr fast dreissig Jahren zwei Vermutungen formuliert, die sich als richtungsweisend erwiesen haben. Es geht darum diejenigen Graphen zu charakterisieren, deren Ramsey Zahlen linear in der Anzahl der Knoten wachsen. Diese Vermutungen besagen, dass Ramsey Zahlen linear fuer alle degenerierten Graphen wachsen und dass die Ramsey Zahlen von Wuerfeln linear wachsen. Ein Ziel dieser Dissertation ist es, abgeschwaechte Varianten dieser Vermutungen zu beweisen. In der topologischen Ramseytheorie bewies Kojman vor kurzem eine topologische Umkehrung des Satzes von Hindman und fuehrte gleichzeitig sogenannte Hindman-Raeume und van der Waerden-Raeume ein (beide sind eine Teilmenge der folgenkompakten Raeume), die jeweils zum Satz von Hindman beziehungsweise zum Satz von van der Waerden korrespondieren. In der Dissertation wird zum einen eine Verstaerkung der Umkehrung des Satzes von van der Waerden bewiesen. Weiterhin wird der Begriff der Differentialkompaktheit eingefuehrt, der sich in diesem Zusammenhang ergibt und der eng mit Hindman-Raeumen verknuepft ist. Dabei wird auch die Beziehung zwischen Differentialkompaktheit und anderen topologischen Raeumen untersucht. Im letzten Abschnitt des zweiten Teils werden kompakte dynamische Systeme verwendet, um ein klassisches Ramsey-Ergebnis von Brown und Hindman et al. ueber stueckweise syndetische Mengen ueber natuerlichen Zahlen und diskreten Halbgruppen auf lokal zusammenhaengende Halbgruppen zu verallgemeinern.In graph Ramsey theory, Burr and Erdos in 1970s posed two conjectures which may be considered as initial steps toward the problem of characterizing the set of graphs for which Ramsey numbers grow linearly in their orders. One conjecture is that Ramsey numbers grow linearly for all degenerate graphs and the other is that Ramsey numbers grow linearly for cubes. Though unable to settle these two conjectures, we have contributed many weaker versions that support the likely truth of the first conjecture and obtained a polynomial upper bound for the Ramsey numbers of cubes that considerably improves all previous bounds and comes close to the linear bound in the second conjecture. In topological Ramsey theory, Kojman recently observed a topological converse of Hindman's theorem and then introduced the so-called Hindman space and van der Waerden space (both of which are stronger than sequentially compact spaces) corresponding respectively to Hindman's theorem and van der Waerden's theorem. In this thesis, we will strengthen the topological converse of Hindman's theorem by using canonical Ramsey theorem, and introduce differential compactness that arises naturally in this context and study its relations to other spaces as well. Also by using compact dynamical systems, we will extend a classical Ramsey type theorem of Brown and Hindman et al on piecewise syndetic sets from natural numbers and discrete semigroups to locally connected semigroups.
4
Rockhoff, Vivian. "Vergleichende Untersuchung von Agarplatten-Oberflächen-Verfahren und Most-Probable-Number-Methode zur Desinfektionsmittelprüfung gemäß den CEN-Normen EN 1656 und EN 1657." Doctoral thesis, Universitätsbibliothek Leipzig, 2008. http://nbn-resolving.de/urn:nbn:de:bsz:15-20080528-081558-7.
Full textAbstract:
Im Rahmen der vorliegenden Arbeit wurden fünf verschiedene Desinfektionsmittel mit drei verschiedenen Keimen mit einem quantitativen Suspensionsversuch auf ihre Wirksamkeit geprüft, dabei wurden jeweils 10 voneinander unabhängige Wiederholungen durchgeführt. Parallel wurden mithilfe laboranalytischer Methoden die Keimzahlermittlung nach EN 1656 und EN 1657 des Europäischen Komitees für Normung (CEN) im Oberflächenverfahren und die Keimzahlermittlung nach der Most-Probable-Number-Methode (MPN) gegenübergestellt und verglichen. Es sollte geprüft werden, ob durch Anwendung des MPN-Verfahrens eine Reduktion des Arbeits- und Zeitaufwands bei gleichwertigen Ergebnissen erreicht werden kann. Hierbei wurde die MPN-Methode sowohl im Röhrchen, als auch in der Mikrotiterplatte durchgeführt. Somit sollte nicht nur ein Vergleich innerhalb der MPN-Verfahren erfolgen, sondern auch eine Aussage getroffen werden, ob das Oberflächen-Verfahren nach CEN auch durch eine weniger aufwändige Mikro-MPN-Methode möglich wäre. Für den direkten Vergleich der Methoden wurden die durch die Versuche und ihre Auswertung ermittelten Reduktionszahlen aus Oberflächen- und MPN-Verfahren statistisch miteinander verglichen. Zusätzlich wurden praktische Vergleiche angestellt, in dem man die ausreichend bakterizid wirksamen Desinfektionsmittelkonzentrationsstufen miteinander verglichen hat. Somit sollte ermittelt werden, welche der drei Methoden (Oberflächenverfahren, Most-Probable-Number-Methode im Röhrchen, Most-Probable-Number-Methode in der Mikrotiter-platte) eine Konzentrationsstufe als ausreichend bakterizid wirksam erachtet, die im Vergleich die höchste Desinfektionsmittelkonzentrationsstufe darstellt und somit in der Praxis das sicherste Desinfektionsergebnis ermöglicht. Vom Oberflächen-verfahren um eine Stufe höher abweichende ausreichend bakterizid wirksame Konzentrationsstufen konnten nur in 18% der Fälle und um eine Stufe niedrigere lediglich in 5,3% der Fälle ermittelt werden. Die Tendenz, dass das MPN-Verfahren höhere Desinfektionsmittelkonzentrationsstufen als bakterizid wirksam prüft, lässt den Schluss zu, dass das MPN-Verfahren sowohl im Röhrchen, als auch in der Mikrotiterplatte gleichwertige und in 18% der Fälle sogar strengere Bewertungen von Desinfektionsmitteln liefert. Um die Methoden statistisch miteinander vergleichen zu können, wurden die ermittelten Reduktionszahlen auf signifikante Unterschiede geprüft. Signifikante Unterschiede zum OFV konnten für beide MPN-Verfahren in 53,3% der Fälle nachgewiesen werden. Davon waren 46,6% signifikant niedrigere Reduktionszahlen als im OFV, lediglich 6,6% der Signifikanzen waren durch höhere Reduktionszahlen gekennzeichnet. Für die Desinfektionsmittelprüfungen ergeben sich hieraus bedeutsame Unterschiede, die dadurch gekennzeichnet sind, dass bei signifikant niedrigeren Reduktionszahlen mehr Keime überlebt und deshalb weniger Keime reduziert und damit abgetötet wurden. Tendenziell werden somit die Prüfbedingungen für Desinfektionsmittel mithilfe der MPN-Methodik erschwert und man kann in diesem Fall von einer sensibleren Desinfektionsmittelprüfung sprechen, bei der einer Fehlbeurteilung von Desinfektionsmitteln vorgebeugt werden kann. Mithilfe der vorliegenden Arbeit konnte eine deutliche Zeitersparnis der MPN-Methodik gegenüber dem Oberflächenverfahren durch Reduzierung der Prüfdauer und damit verbundene Erhöhung des Probendurchsatzes nachgewiesen werden. Des Weiteren ist der Materialeinsatz bei den MPN-Verfahren und hier vor allem in der Mikrotiterplatte sehr viel geringer und damit weniger kostenintensiv als beim Oberflächenverfahren.
5
Chabut, Barbara. "Complexes binucléaires à fer non-heminique : activité biomimétique et échange de ligands." Université Joseph Fourier (Grenoble ; 1971-2015), 1997. http://www.theses.fr/1997GRE10234.
Full textAbstract:
Notre travail s'inscrit dans le cadre de la recherche de complexes modeles de sites actifs binucleaires d'enzymes a fer non heminique et plus particulierement de l'hemerythrine et de la methane monooxygenase. Pour cela, nous avons synthetise des composes dans lesquels le centre binucleaire est dissymetrique, c'est a dire que les deux ions metalliques sont dans des environnements differents. Ainsi lors de la synthese de complexes a valence mixte, fe#i#i#ife#i#i, l'ion ferrique est dans un environnement n#3o#3 alors que l'ion ferreux se trouve dans un environnement n#2o#3x, un ligand exogene completant sa sphere de coordination. Notre projet s'articule ensuite principalement autour de deux axes : - l'etude de la structure electronique du centre a fer suivant les conditions de solvatation et d'hydratation du milieu, donc suivant la nature du ligand x. On montre par ces experiences que les proprietes spectroscopiques et electrochimiques des complexes varient suivant si x est une molecule d'acetonitrile ou une molecule d'eau et, de plus, lors de l'oxydation de la forme fe#i#i#ife#i#i-oh#2 il se produit une deprotonation spontanee pour conduire a une espece fe#i#i#ife#i#i#i-oh. - la capacite des complexes a catalyser des reactions d'hydroxylation de substrats, en presence de donneurs d'oxygene. Les resultats obtenus indiquent que les complexes possedent une activite monooxygenase et, de plus, en presence de toluene, il se produit une hydroxylation en position ortho pour donner comme produit d'oxydation l'ortho-cresol, ce qui modelise la reactivite de la toluene-2-monooxygenase. Enfin, dans une derniere partie, nous presentons la structure d'un nouveau complexe possedant une entite fe#i#i#i#2(-oh)#2.
6
Yehya, Yassar. "Propagation des ondes acoustiques dans les conduites cylindriques de révolution." Poitiers, 1988. http://www.theses.fr/1988POIT2275.
Full textAbstract:
Etude de l'influence de l'ecoulement dans le cas de propagation non dispersive. Aux petits nombres de mach la solution de la propagation dispersive est donnee sous la forme d'un developpement en serie du nombre de mach (methode de perturbation). Dans le cas general, l'equation est resolue par la methode galerkin
7
Rifi, Mohamad Azzam. "Propagation d'ondes dans un canal plan en presence d'ecoulement." Poitiers, 1987. http://www.theses.fr/1987POIT2318.
Full textAbstract:
La propagation du mode fondamental est etudiee au moyen de l'equation de la pression (sans dispersion). Les autres situations sont abordees au moyen d'une methode de perturbation. Une approche variationnelle est egalement envisagee
8
RASOLOARIJAONA, MAMY NIRINA. "Non-linearites de la loi de darcy : etudes theorique, numerique et experimentale." Grenoble 1, 1993. http://www.theses.fr/1993GRE10124.
Full textAbstract:
Nous etudions la filtration en milieu poreux de fluides newtoniens en utilisant la theorie d'homogeneisation des structures periodiques. Dans un premier temps nous rappelons les resultats obtenus grace a la methode dans les cas de l'ecoulement stationnaire de fluides incompressibles ou compressibles, et de l'acoustique de fluides incompressibles. Dans le premier cas, la filtration est decrite par la loi de darcy, la compressibilite etant prise en compte dans le bilan de masse. Dans le second cas, la loi macroscopique est une loi de darcy generalisee: le tenseur de permeabilite est a valeur complexe et depend de la frequence. Nous etendons ensuite notre etude a la recherche d'une correction faiblement non lineaire a la loi de darcy, le nombre de reynolds re microscopique etant suppose petit. L'ecoulement est suppose stationnaire et le fluide incompressible. Le nombre de reynolds microscopique est pris re=0(). En appliquant les resultats aux filtrations unidirectionnelles, la loi macroscopique est une loi cubique sans terme quadratique. On retrouve le meme terme cubique auquel est adjoint un terme du type (v. Grad)v dans le cas d'un milieu isotrope et homogene. Lorsque re0(), le terme cubique n'apparait pas et lorsque 0()re1, on obtient le terme cubique seul. Finalement, nous effectuons une etude experimentale ainsi qu'un calcul numerique sur un modele monodimensionnel. Les deux etudes portent sur un nombre de reynolds local allant de 0 a 150. Il existe une bonne correspondance entre les resultats numeriques et experimentaux. Ces resultats confirment la loi cubique
9
Le, Peutre Yvonnick. "Simulation numerique des ecoulements de convection naturelle tridimensionnels en cavite chauffee differentiellement." Nantes, 1989. http://www.theses.fr/1989NANT2018.
Full textAbstract:
Simulation des ecoulements de convection naturelle laminaire d'un fluide incompressible confine dans une cavite parallelepipedique. Les equations de navier-stokes sont ecrites en formulation vecteurs potentiel-rotationnel
10
Schnabel, Uwe. "Berechnung singulärer Punkte nichtlinearer Gleichungssysteme." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2000. http://nbn-resolving.de/urn:nbn:de:swb:14-994854043859-72573.
Full textAbstract:
Diese Arbeit beschäftigt sich mit der Berechnung singulärer Punkte nichtlinearer Gleichungssysteme F(x)=0. Dazu werden minimal erweiterte Systeme der Form F(x)+D*s=0, f(x)=0 betrachtet. Die allgemeine Vorgehensweise zur Berechnung singulärer Punkte mit solchen erweiterten Systemen wird geschlossen dargestellt. Dazu werden zuerst die (teilweise verallgemeinerten Ljapunov-Schmidt-)reduzierten Funktionen von Golubitsky und Schaeffer, Beyn, Jepson und Spence, Griewank und Reddien, Kunkel bzw. Govaerts verallgemeinert und zusammengefasst. Es wird die verallgemeinerte Kontaktäquivalenz all dieser verallgemeinerten reduzierten Funktionen und die Gleichheit der benötigten Regularitätsannahmen bewiesen. Für eine weitere, neu eingeführte reduzierte Funktion wird die in dieser Arbeit definierte Ableitungsäquivalenz zu den anderen reduzierten Funktionen gezeigt. Mit dieser neuen reduzierten Funktion wird eine Reihe singulärer Punkte klassifiziert. Aus dieser Klassifikation ergeben sich Funktionen f aus Ableitungen der neuen reduzierten Funktion. Mit den so eingeführten Funktionen f kann das zweistufiges Newtonverfahren nach Pönisch und Schwetlick effektiv angewendet werden. Alle benötigten Ableitungen werden mittels Automatischer Differentiation bestimmt. Die numerischen Ergebnisse für eine Reihe von Beispielen zeigen die Effizienz dieses Verfahrens. Beim Newtonverfahren werden lineare Gleichungssysteme mit geränderten Matrizen B gelöst. Es wird gezeigt, für welche Ränderungen die Konditionszahl von B minimal ist. Dies ist z.B. für gewisse Vielfache der Singulärvektoren zu den kleinsten Singulärwerten der Fall. Zur Bestimmung dieser Ränderungen wird die inverse Teilraumiteration für Singulärwerte in verschiedenen Algorithmen angewendet. Die Konvergenzeigenschaften werden untersucht. Für einen Algorithmus wird bewiesen, dass die Konditionszahlen der iterierten geränderten Matrizen monoton fallen. Die numerischen Experimente bestätigen diese Eigenschaften.
Books on the topic "Methane number"
1
Reichelt, Herbert. Eine Methode der statistischen Komponentenzerlegung: Konzept einer erweiterten Index-Analyse volkswirtschaftlicher Änderungsraten. Bonn: Wissenschaftliches Institut der Ortskrankenkassen, 1988.
Find full text
2
Paulos, John Allen. Once upon a number: The hidden mathematical logic of stories. New York, NY: Basic Books, 1998.
Find full text
3
Burton, R. F. Biology by numbers: An encouragement to quantitative thinking. Cambridge: Cambridge University Press, 1998.
Find full text
4
Quantitative methods in educational research: The role of numbers made easy. London: Continuum, 2001.
Find full text
5
Quantitative arithmetic of projective varieties. Basel: Birkhäuser, 2009.
Find full text
6
Laurencelle, Louis. Hasard, Nombres Aleatoires Et Methode Monte Carlo. Presses de L'Universite Du Quebec, 2001.
Find full text
7
Hicks, Hamilton, and Srinivas Muvvala. Methadone Maintenance versus Detoxification and Psychosocial Treatment for Opioid Dependence. Edited by Ish P. Bhalla, Rajesh R. Tampi, Vinod H. Srihari, and Michael E. Hochman. Oxford University Press, 2018. http://dx.doi.org/10.1093/med/9780190625085.003.0048.
Full textAbstract:
This chapter provides a summary of a landmark study on substance use disorders. The study authors tackle a fundamental question in the treatment of opioid dependence. Should patients with opioid dependence be treated with methadone maintenance treatment or prolonged and psychosocially enriched methadone-assisted detoxification? Starting with that question, this chapter describes the basics of the study, including the funding source, study location, who was studied, number of study participants, study design, study interventions, follow-up, study endpoints, results, as well as criticism and limitations. The chapter briefly reviews other relevant studies and information, discusses implications, and concludes with a relevant clinical case.
8
Paulos, John Allen. Once Upon a Number : The Hidden Mathematical Logic of Stories. Basic Books, 1999.
Find full text
9
Gorard, Stephen. Quantitative Methods in Educational Research: The Role of Numbers Made Easy. Continuum International Publishing Group, 2001.
Find full text
10
Quantitative Methods in Educational Research: The Role of Numbers Made Easy. Continuum International Publishing Group, 2001.
Find full textBook chapters on the topic "Methane number"
1
Zaman, M., K. Kleineidam, L. Bakken, J. Berendt, C. Bracken, K. Butterbach-Bahl, Z. Cai, et al. "Isotopic Techniques to Measure N2O, N2 and Their Sources." In Measuring Emission of Agricultural Greenhouse Gases and Developing Mitigation Options using Nuclear and Related Techniques, 213–301. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-55396-8_7.
Full textAbstract:
AbstractGHGemissions are usually the result of several simultaneous processes. Furthermore, some gases such as N2 are very difficult to quantify and require special techniques. Therefore, in this chapter, the focus is on stable isotopemethods. Both natural abundance techniques and enrichment techniques are used. Especially in the last decade, a number of methodological advances have been made. Thus, this chapter provides an overview and description of a number of current state-of-the-art techniques, especially techniques using the stable isotope15N. Basic principles and recent advances of the 15N gasflux method are presented to quantify N2 fluxes, but also the latest isotopologue and isotopomermethods to identify pathways for N2O production. The second part of the chapter is devoted to 15N tracing techniques, the theoretical background and recent methodological advances. A range of different methods is presented from analytical to numerical tools to identify and quantify pathway-specific N2O emissions. While this chapter is chiefly concerned with gaseous N emissions, a lot of the techniques can also be applied to other gases such as methane (CH4), as outlined in Sect. 10.1007/978-3-030-55396-8_5#Sec12.
2
"REGISTRY NUMBER INDEX." In Methane, 772–75. Elsevier, 1987. http://dx.doi.org/10.1016/b978-0-08-029200-7.50037-0.
Full text
3
Broom, Donald M. "Dairy cattle welfare and other aspects of sustainability." In Understanding the behaviour and improving the welfare of dairy cattle, 1–14. Burleigh Dodds Science Publishing, 2021. http://dx.doi.org/10.19103/as.2020.0084.01.
Full textAbstract:
Welfare and other aspects of sustainability are becoming increasingly important in consumer purchasing decisions. This chapter introduces a number of key welfare issues affecting the dairy industry that need system change, including lameness, mastitis and aspects of calf management. Other major topics concerning the sustainability of dairy production are: minimising grain use, feeding high protein leaves of shrubs and trees, reducing greenhouse gas emissions such as by changing diet to reduce methane output, and improving labelling and traceability.
4
Calvert, Jack G., John J. Orlando, William R. Stockwell, and Timothy J. Wallington. "The Hydroxyl Radical and Its Role in Ozone Formation." In The Mechanisms of Reactions Influencing Atmospheric Ozone. Oxford University Press, 2015. http://dx.doi.org/10.1093/oso/9780190233020.003.0007.
Full textAbstract:
Although the HO radical is present in the sunlight-irradiated troposphere at very low concentrations, only about 106 molecules cm−3, it is the most important trace component in our atmosphere. It is a highly reactive transient species and is responsible for initiating the oxidation of the majority of organic compounds in the troposphere. It initiates the chain reactions that produce ozone. All the saturated, H-atom containing molecules react with HO through abstraction of an H atom. In the case of the simplest alkane, methane, reaction (1) leads to the formation of a water molecule and an alkyl (CH3) radical: . . . HO + CH4 → H2O + CH3 (1) . . . The CH3 radical released into the oxygen-rich atmosphere quickly adds O2 to give the methyl peroxy radical in reaction (2), which in NO-containing atmospheres can react to form NO2, and an alkoxy radical, CH3O, in reaction (3). In turn, this radical reacts with O2 to give an HO2 radical and a molecule of formaldehyde in (4). An HO radical can be regenerated as the HO2 molecule oxidizes NO to NO2 in (5), and the chain of events, reactions (1) through (5), leads to ozone generation through the photolysis of the NO2 molecule in reactions (6) and (7): . . . CH3 + O2 → CH3O2 (2) . . . . . . CH3O2 + NO → CH3O + NO2 (3) . . . . . . CH3O + O2 → HO2 + CH2O (4) . . . HO2 + NO → HO + NO2 (5) . . . . . . NO2 + hν → O + NO (6) . . . . . . O + O2 (+ M) → O3 (+ M) (7) . . . Methane is the least reactive of the alkanes with HO. Urban atmospheres contain a complex mixture of the more reactive larger alkanes (RH). The number of different possible geometric isomers and stereoisomers of the alkanes that can be formed by association of C and H atoms is astounding (Calvert et al., 2008). For example, there are more than a thousand structurally different molecules of molecular formula C12H26, more than a million C20H22, more than a billion of formula C25H52, and more than a trillion possible different isomers of molecular formula C31H64.
5
Windrich, H. "Die Methode der zeitvarianten Linearisiening." In Zeitschrift für Angewandte Mathematik und Mechanik Volume 70, Number 8, 347–49. De Gruyter, 1990. http://dx.doi.org/10.1515/9783112571088-013.
Full text
6
Büttner, R., B. Uebel, and I. Genz. "Der substratlimitierte pH-Auxostat — Eine neue Methode zur kontinuierlichen Kultur." In Acta Biotechnologica Volume 6, Number 2, 129–32. De Gruyter, 1986. http://dx.doi.org/10.1515/9783112533000-005.
Full text
7
Haas, R., and H. Bkauchli. "Genauigkeit der Boundary-Element-Methode für lineare Torsion." In Zeitschrift für Angewandte Mathematik und Mechanik Volume 65, Number 5, 266–68. De Gruyter, 1985. http://dx.doi.org/10.1515/9783112570784-005.
Full text
8
Hiller, M., and A. Kecskemethy. "Eine vereinfachte Methode zur Aufstellung der Bewegungsgleichungen ebener Mechanismen." In Zeitschrift für Angewandte Mathematik und Mechanik Volume 66, Number 4, 42–43. De Gruyter, 1986. http://dx.doi.org/10.1515/9783112550922-013.
Full text
9
Calvert, Jack, Abdelwahid Mellouki, John Orlando, Michael Pilling, and Timothy Wallington. "Rate Coefficients and Mechanisms for the Atmospheric Oxidation of the Aldehydes." In Mechanisms of Atmospheric Oxidation of the Oxygenates. Oxford University Press, 2011. http://dx.doi.org/10.1093/oso/9780199767076.003.0007.
Full textAbstract:
Aldehydes are emitted from a variety of anthropogenic sources associated with natural gas and petroleum combustion (for examples, see tables I-C-2 and I-C-3). Winer et al. (1992) have discussed direct emissions of aldehydes from biogenic sources. They are also important intermediates in the oxidation of directly emitted organic compounds. For example, formaldehyde, CH2O formed in the reaction of CH3O with O2 . . . CH3O + O2 → CH2O + HO2 . . . CH3O is formed in the oxidation of methane, and a number of other compounds. There are also many other sources of CH2O; for example, the Leeds University’s Master Chemical Mechanism (MCM) lists a total of ∼ 140 CH2O precursors: http://mcm.leeds.ac.uk/MCM/. Aldehydes with saturated hydrocarbon chains (termed alkanals or acyclic aldehydes) react mainly with OH during the day and with NO3 at night. The aldehydic C—H bond is weaker than those in the hydrocarbon chain; and, certainly for the shorter carbon chain species, abstraction by both OH and NO3 occurs primarily at the aldehydic center to form an acyl radical which reacts rapidly with O2 to form an acylperoxy radical, e.g., . . . CH3CHO + OH → CH3CO + H2O . . . . . . CH3CO + O2 → CH3C(O)O2 . . . An important reaction of the acylperoxy radical is with NO2 to form an acylperoxy nitrate. In the example shown, the oxidation of acetaldehyde gives acetyl peroxy radicals which can react with NO2 to form peroxyacetyl nitrate, CH3C(O)O2NO2, generally known as PAN: . . . CH3C(O)O2 + NO2 → CH3C(O)O2NO2 . . . Peroxyacyl nitrates dissociate quite quickly at 298 K, to regenerate peroxyacyl radicals. For example, PAN has a lifetime of about 50 min. The lifetime increases rapidly at the lower temperatures experienced at higher altitudes and is several months at the temperatures (∼ 250 K) of the upper troposphere. This long lifetime provides a mechanism for the transport of NOx from polluted areas to less polluted areas, by transfer of peroxyacyl nitrates from the boundary layer to the free troposphere; subsequent subsidence can return them to the boundary layer where they dissociate at the higher temperatures encountered there. The atmospheric reactions of the nitrates are discussed in detail in chapters VIII and IX.
10
Frey, Perry A., and Adrian D. Hegeman. "Alkyltransferases." In Enzymatic Reaction Mechanisms. Oxford University Press, 2007. http://dx.doi.org/10.1093/oso/9780195122589.003.0019.
Full textAbstract:
A number of enzymes catalyze alkylation reactions, most of which are reactions of S-adenosyl-L-methionine (SAM) as a methylating agent in the biosynthesis of hormones, modification of DNA, and methyl esterification of proteins involved in signal transduction. Other examples of enzymatic alkylation include prenyl transfer reactions, adenosyltransfer from ATP to methionine in the biosynthesis of SAM, and adenosyltransfer from ATP to cob(I)alamin in the biosynthesis of adenosylcobalamin. Methyl group transfer is also the essential step in the reaction of methionine synthase, which uses 5-methyltetrahydrofolate as an alkylating agent. In an analogous reaction, an analog of 5-methyltetrahydrofolate is the methyl group donor in the methylation of coenzyme M to form methyl coenzyme M, the proximate precursor of methane in methanogenesis (see chap. 4). Glysosyl transfer is an alkylation reaction catalyzed by a large class of enzymes, the glycosyltransferases and glycosidases. The special nature of the glycosyl compounds and their potential for undergoing glycosyltransfer places them in their own class in biochemistry (see chap. 12). The reactivity of glycosyl compounds can be attributed to the contribution of the oxygen atom directly bonded to the glycosyl carbon, the locus of alkylation. In this chapter, we consider other enzymatic alkylations. Alkylation consists of the transfer of a carbon from a leaving group to a nucleophilic acceptor, as in eq.15-1, where R is H or an organic group. The rate is controlled by the reactivity of the nucleophile X:, the stability of the leaving group Y:, and the electrophilic reactivity of the central carbon atom. Alkylation may be regarded as one of the simplest organic chemical reactions because there are few complications in the mechanism. It is the reaction of a nucleophilic molecule with an electrophilic molecule to displace a leaving group. Enzymatic alkylations proceed by polar and not radical mechanisms. In organic chemistry, polar alkylation can occur either by an associative or one-step mechanism, as in fig. 15-1A, or by a dissociative or two-step mechanism through a carbocationic intermediate, as in fig. 15-1B. The chemical nature of the alkylating agent, the propensity of the leaving group to leave, and the polarity of the solvent determine the mechanism.
Conference papers on the topic "Methane number"
1
Wise, Daniel M., Daniel B. Olsen, and Myoungjin Kim. "Characterization of Methane Number for Producer Gas Blends." In ASME 2013 Internal Combustion Engine Division Fall Technical Conference. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/icef2013-19221.
Full textAbstract:
Producer gas, any of a variety of gases generated from biomass gasification, is a renewable gaseous fuel that can be burned in gas engines for power production. Producer gas consists primarily of methane, hydrogen, carbon monoxide, carbon dioxide, and nitrogen. These gas blends can be problematic as a fuel for natural gas engines due to widely varying composition and significantly different fuel properties than natural gas. Characterization of combustion properties of different producer gas compositions is critical if the gas engine is to be operated reliably and at the greatest efficiency possible. A sample space of 35 producer gas blends consisting of distinct percentages of combustible gases (methane, hydrogen, and carbon monoxide) and diluent (carbon dioxide and nitrogen) is created to provide a basis for methane number testing. A test cell is established to mix producer gas blends of desired constituent makeup for consumption in a Waukesha F2 Cooperative Fuel Research (CFR) engine to directly measure methane number for each blend. Additional measurements include combustion pressure statistics, fuel consumption, and power output. Methane number is correlated to combustion pressure statistics and producer gas properties. Methane number measurements are compared with predictions using the software AVL Methane, often employed by engine manufacturers to characterize gaseous fuels. Measured methane number shows a strong correlation to 0–10% and 10–90% burn durations. The predicted methane number values from AVL Methane are significantly different than measured methane number in many cases. The error in the prediction is strongly dependent on the amount of carbon monoxide and hydrogen in the producer gas.
2
Ohlrogge, K., M. Zettlitzer, U. Hartmann, D. Bobe, J. Wind, and T. Brinkmann. "Methane Number Control of Associated Gas from Oil Production." In SPE Gas Technology Symposium. Society of Petroleum Engineers, 2002. http://dx.doi.org/10.2118/75509-ms.
Full text
3
Eilts, Peter, and Lennart Klare. "Investigations on the Determination of the Service Methane Number of LNG." In WCX World Congress Experience. 400 Commonwealth Drive, Warrendale, PA, United States: SAE International, 2018. http://dx.doi.org/10.4271/2018-01-1143.
Full text
4
Saikaly, Khalil, Olivier Le Corre, Camal Rahmouni, and Laurent Truffet. "Normalized Knock Indicator for Natural Gas S.I. Engines: Methane Number Requirements Prediction." In ASME 2009 Internal Combustion Engine Division Fall Technical Conference. ASMEDC, 2009. http://dx.doi.org/10.1115/icef2009-14032.
Full textAbstract:
Design of engines and associated nominal settings are normally computed and optimized so as to provide maximum performance, i.e. compromise between efficiency and emissions. For Combined Heat and Power (CHP) applications fuelled by gas network, this conception is adapted for a large range of gas chemical composition, up to a limit. The indicator used to describe gas quality is the methane number (MN). Hence, engine manufacturers normally supply specific information such as nominal engine settings and its associated limit value for the methane number (MNL). When the engine is operating under its nominal settings, a low grade gas (MN < MNL) can lead to engine knock. Knock is caused by auto-ignition of the end gas ahead of the flame in spark-ignition engine. Heavy knock can severely damage engine piston, constituting a main constraint for optimization of engine operating conditions. For an engine setting ES, (the vector ES includes the spark advance SA, the air fuel ratio AFR and the load), methane number requirement (MNR) is defined such as the minimum value of MN above which no-knock is ensured. The objective of this paper is to predict MNR as a function of engine setting for three engines. Simulation results show that the critical value of the considered knock criterion varies from an engine to another. A new normalized knock indicator based on the energy ratio is proposed to enable this comparison: laminar flame speed is assumed to be more sensible to MN variation than internal fluid dynamics (swirl, tumble, and squish) due to engine design.
5
Kreutzer, Cory J., Daniel B. Olsen, and Robin J. Bremmer. "Evaluation of a Lean-Burn Natural Gas Engine Operating on Variable Methane Number Fuel." In ASME 2011 Internal Combustion Engine Division Fall Technical Conference. ASMEDC, 2011. http://dx.doi.org/10.1115/icef2011-60071.
Full textAbstract:
Wellhead gas from which pipeline natural gas originates has significant variability in composition due to natural variations in deposits. Gas quality is influenced by relative concentrations of both inert and hydrocarbon species. Gas compression engines utilizing wellhead gas as a fuel source often require significant installation time and adjustment of stock configuration due to fuel compositions that vary with time and location. Lean burn natural gas engines are chosen as wellhead compression engines for high efficiency and low emissions while minimizing the effect of variable gas composition. Ideal engine conditions are maintained by operating within the knock and misfire limits of the engine. Additional data is needed to find engine operational limitations. In this work, experimental data was collected on a Cummins GTA8.3SLB engine operating on variable methane number fuel under closed-loop equivalence ratio control. A fuel blending system was used to vary methane number to simulate wellhead compositions. NOx and CO emissions were found to increase with decreasing methane number while combustion stability remained constant. In addition, the effects of carbon dioxide and nitrogen diluents in the fuel were investigated. When diluents were present in the fuel, engine performance could be maintained by spark timing advance.
6
Brecq, Guillaume, Camal Rahmouni, Abdellilah Taouri, Mohand Tazerout, and Olivier Le Corre. "Service Methane Number as a Means to Avoid Knock in Natural Gas Fuelled Spark Ignition Engines." In ASME 2003 Internal Combustion Engine Division Spring Technical Conference. ASMEDC, 2003. http://dx.doi.org/10.1115/ices2003-0573.
Full textAbstract:
Experimental investigations on the knock rating of gaseous fuels were carried out on a single cylinder SI engine of Lister-Petter make. The Service Methane Number (SMN) of different gas compositions is measured and then compared to the standard Methane Number (MN), calculated by the AVL software. Effects of engine parameters, by mean of the Methane Number Requirement (MNR) are also highlighted. A linear correlation, between the SMN and the MN, has been obtained with a maximum absolute deviation lower than 2 MN units. A prediction correlation giving the MNR from engine parameters has finally been deduced from experimental data with a good accuracy (mean absolute deviation of 0.5 MNR unit).
7
Wise, Daniel M., Daniel B. Olsen, and Myoungjin Kim. "Development of a Lean Burn Methane Number Measurement Technique for Alternative Gaseous Fuel Evaluation." In ASME 2013 Internal Combustion Engine Division Fall Technical Conference. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/icef2013-19220.
Full textAbstract:
A wide range of fuels are used in industrial gas fueled engines. Fuels include well-head gas, pipeline natural gas, producer gas, coal gas, digester gas, landfill gas, and liquefied petroleum gas. Many industrial gas fueled engines operate at high power density and at ultra-lean air-fuel ratios for low NOx emissions. Engines operate in a narrow air-fuel ratio band between misfire and knock limits. To utilize this wide range of fuels effectively it is important to understand knock properties. Methane number determination for natural gas blends is traditionally performed with research engines at stoichiometric conditions where the onset of knock is identified through subjective audible indication. The objective of this paper is to develop a process to determine knock onset through direct indication from pressure transducer data at lean operating conditions characteristic of lean-burn industrial gas engines. Validation of the method is provided with methane number determination and comparison of pipeline natural gas. A Waukesha F2 Cooperative Fuel Research (CFR) engine is modified to incorporate piezoelectric pressure transducers at the cylinder head and conversion from natural aspiration to boosted intake and variable exhaust back pressures (to simulate turbocharger operation). The new pressure sensors enable Fast Fourier Transform calculation of pressure data to calculate amplitude at characteristic knock frequency.
8
Abe, Tomotaka, Ken’ichi Hiratsuka, and Czesław Kajdas. "Tribocatalytic Enhancement of Methane Oxidation." In World Tribology Congress III. ASMEDC, 2005. http://dx.doi.org/10.1115/wtc2005-64034.
Full textAbstract:
Oxidation reaction of methane is one of the most fundamental reactions in organic chemistry. This reaction is enhanced by silver catalyst [1]. In this study, we confirmed that the catalytic activity of silver is enhanced more by the friction. This effect is called tribocatalysis. In previous studies about tribocatalysis, we have shown that the oxidation reactions of hydrogen [2], carbon monoxide [3] and ethylene were promoted by the friction. According to NIRAM (negative-ion-radical action mechanism) approach, exo-electron emission triggers the promotion of chemical reactions [4]. Insulator such as aluminum oxide, when it is worn, emits larger number of negative particles including electrons compared with metals [5]. Therefore we expected that the friction of aluminum oxide promotes tribochemical reactions more than metals.
9
Mehrotra, Vibhor, Brigette Rosendall, Alasdair Heath, and Jonathan Berkoe. "CFD Modeling of Steam Methane Reformer." In ASME 2002 Pressure Vessels and Piping Conference. ASMEDC, 2002. http://dx.doi.org/10.1115/pvp2002-1581.
Full textAbstract:
This paper presents the use of advanced computer simulation (coupled Computational Fluid Dynamics and process modeling) to determine the effects of burner change out in a steam-methane reformer (SMR). SMR’s are used to generate hydrogen for oil refinery operation and synthesis gas for chemical plant production. A stream of natural gas and steam reacts inside a large number of catalyst-filled tubes housed inside the SMR furnace. Burner replacement in the furnace can result in reduced hydrogen production, decreased efficiency, and unstable operation. To help select a suitable replacement burner and optimize furnace performance CFD modeling was used to identify the impact of different burners on the following key SMR design parameters: • Local heat flux profiles on the reformer tubes; • Local peak and average reformer tube skin temperatures; • Heat Flux in the pre-heat tubes; • SMR Hydrogen production and process conditions. With a replacement burner selected, the ‘coupled’ CFD model was then used to predict the burner-firing pattern that maximizes hydrogen production within the SMR design constraints.
10
Ikeda, Yuji, Jun Kojima, and Tsuyoshi Nakajima. "Local Damkoehler number measurement in turbulent methane/air flames by local OH*, CH* and C2* chemiluminescence." In 36th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit. Reston, Virigina: American Institute of Aeronautics and Astronautics, 2000. http://dx.doi.org/10.2514/6.2000-3395.
Full textReports on the topic "Methane number"
1
Hirschon, A. S., Y. Du, H. J. Wu, R. Malhotra, and R. B. Wilson. Novel catalysts for methane activation. Quarterly report number 10, January 1--March 31, 1995. Office of Scientific and Technical Information (OSTI), June 1995. http://dx.doi.org/10.2172/113904.
Full text
2
Heath, Garvin A. Reconciling Basin-Scale Top-Down and Bottom-Up Methane Emission Measurements for Onshore Oil and Gas Development: Cooperative Research and Development Final Report, CRADA Number CRD-14-572. Office of Scientific and Technical Information (OSTI), December 2017. http://dx.doi.org/10.2172/1412102.
Full text
3
Pullammanappallil, Pratap, Haim Kalman, and Jennifer Curtis. Investigation of particulate flow behavior in a continuous, high solids, leach-bed biogasification system. United States Department of Agriculture, January 2015. http://dx.doi.org/10.32747/2015.7600038.bard.
Full textAbstract:
Recent concerns regarding global warming and energy security have accelerated research and developmental efforts to produce biofuels from agricultural and forestry residues, and energy crops. Anaerobic digestion is a promising process for producing biogas-biofuel from biomass feedstocks. However, there is a need for new reactor designs and operating considerations to process fibrous biomass feedstocks. In this research project, the multiphase flow behavior of biomass particles was investigated. The objective was accomplished through both simulation and experimentation. The simulations included both particle-level and bulk flow simulations. Successful computational fluid dynamics (CFD) simulation of multiphase flow in the digester is dependent on the accuracy of constitutive models which describe (1) the particle phase stress due to particle interactions, (2) the particle phase dissipation due to inelastic interactions between particles and (3) the drag force between the fibres and the digester fluid. Discrete Element Method (DEM) simulations of Homogeneous Cooling Systems (HCS) were used to develop a particle phase dissipation rate model for non-spherical particle systems that was incorporated in a two-fluid CFDmultiphase flow model framework. Two types of frictionless, elongated particle models were compared in the HCS simulations: glued-sphere and true cylinder. A new model for drag for elongated fibres was developed which depends on Reynolds number, solids fraction, and fibre aspect ratio. Schulze shear test results could be used to calibrate particle-particle friction for DEM simulations. Several experimental measurements were taken for biomass particles like olive pulp, orange peels, wheat straw, semolina, and wheat grains. Using a compression tester, the breakage force, breakage energy, yield force, elastic stiffness and Young’s modulus were measured. Measurements were made in a shear tester to determine unconfined yield stress, major principal stress, effective angle of internal friction and internal friction angle. A liquid fludized bed system was used to determine critical velocity of fluidization for these materials. Transport measurements for pneumatic conveying were also assessed. Anaerobic digestion experiments were conducted using orange peel waste, olive pulp and wheat straw. Orange peel waste and olive pulp could be anaerobically digested to produce high methane yields. Wheat straw was not digestible. In a packed bed reactor, anaerobic digestion was not initiated above bulk densities of 100 kg/m³ for peel waste and 75 kg/m³ for olive pulp. Interestingly, after the digestion has been initiated and balanced methanogenesis established, the decomposing biomass could be packed to higher densities and successfully digested. These observations provided useful insights for high throughput reactor designs. Another outcome from this project was the development of low cost devices to measure methane content of biogas for off-line (US$37), field (US$50), and online (US$107) applications.
4
Mizrahi, Itzhak, and Bryan A. White. Uncovering rumen microbiome components shaping feed efficiency in dairy cows. United States Department of Agriculture, January 2015. http://dx.doi.org/10.32747/2015.7600020.bard.
Full textAbstract:
Ruminants provide human society with high quality food from non-human-edible resources, but their emissions negatively impact the environment via greenhouse gas production. The rumen and its resident microorganisms dictate both processes. The overall goal of this project was to determine whether a causal relationship exists between the rumen microbiome and the host animal's physiology, and if so, to isolate and examine the specific determinants that enable this causality. To this end, we divided the project into three specific parts: (1) determining the feed efficiency of 200 milking cows, (2) determining whether the feed- efficiency phenotype can be transferred by transplantation and (3) isolating and examining microbial consortia that can affect the feed-efficiency phenotype by their transplantation into germ-free ruminants. We finally included 1000 dairy cow metadata in our study that revealed a global core microbiome present in the rumen whose composition and abundance predicted many of the cows’ production phenotypes, including methane emission. Certain members of the core microbiome are heritable and have strong associations to cardinal rumen metabolites and fermentation products that govern the efficiency of milk production. These heritable core microbes therefore present primary targets for rumen manipulation towards sustainable and environmentally friendly agriculture. We then went beyond examining the metagenomic content, and asked whether microbes behave differently with relation to the host efficiency state. We sampled twelve animals with two extreme efficiency phenotypes, high efficiency and low efficiency where the first represents animals that maximize energy utilization from their feed whilst the later represents animals with very low utilization of the energy from their feed. Our analysis revealed differences in two host efficiency states in terms of the microbial expression profiles both with regards to protein identities and quantities. Another aim of the proposal was the cultivation of undescribed rumen microorganisms is one of the most important tasks in rumen microbiology. Our findings from phylogenetic analysis of cultured OTUs on the lower branches of the phylogenetic tree suggest that multifactorial traits govern cultivability. Interestingly, most of the cultured OTUs belonged to the rare rumen biosphere. These cultured OTUs could not be detected in the rumen microbiome, even when we surveyed it across 38 rumen microbiome samples. These findings add another unique dimension to the complexity of the rumen microbiome and suggest that a large number of different organisms can be cultured in a single cultivation effort. In the context of the grant, the establishment of ruminant germ-free facility was possible and preliminary experiments were successful, which open up the way for direct applications of the new concepts discovered here, prior to the larger scale implementation at the agricultural level.
5
Browdy, Craig, and Esther Lubzens. Cryopreservation of Penaeid Shrimp Embryos: Development of a Germplasm Cryo-Bank for Preservation of High Health and Genetically Improved Stocks. United States Department of Agriculture, August 2002. http://dx.doi.org/10.32747/2002.7695849.bard.
Full textAbstract:
The objectives of the project were to develop a successful protocol for cryopreservation of penaeid germ plasm in order to preserve a pathogen-free broodstock nucleus for commercial exploitation of marine shrimp in aquaculture. The critical parameters to be characterized in the project were: 1. Determination of chill sensitivity and chill tolerant embryonic stages, including a full description and time course study of embryonic developmental stages. 2. Development of protocols for loading and removal of cryoprotectant agents (CPAs) from embryos; determination of optimal concentrations and duration of loading. 3. Characterization of the toxicity of the selected CP As and 4. Establishing optimal cooling and thawing procedures. Studies were performed on two penaeid species: Litopenaeus vannamei (in the USA) and P. semisulcatus (in Israel). The effect of incubation temperature on embryonic development rate and hatching success was studied in L. vannamei, showing that spawns maybe maintained at temperatures ranging from 24°C to 30°C, without compromising hatchability. Embryonic development extends from 12 hr to 19 hr at 30°C and 24°C, respectively. Studies showed that advanced embryonic developmental stages were chill tolerant in the two studied species, but P. semisulcatus could better endure lower temperatures than L. vannamei. A large number of experiments were performed to determine the optimal CP As, their concentration and duration of loading. Permeating (e.g. glycerol, methanol, DMSO, 1,2- propanediol, ethylene glycol, glucose) and non-permeating CPAs (sucrose, PVP, polyethylene glycol) were tested and several combinations of permeating and non-permeating CP As, on fertilized eggs (embryos), nauplii and protozoeae. In general, nauplii tolerated higher CPA concentrations than eggs and nauplii were also more permeable to radiolabeled methanol. Chlorine treatment intended to remove the chitinous envelop from eggs, did not increase dramatically the permeation of radiolabled methanol into eggs. Cooling eggs, nauplii or protozoeae to cryogenic temperatures, by either vitrification or slow cooling protocols, did not result in full survival of thawed samples, despite exhaustive attempts testing various protocols and CP As. Results seemed more encouraging in freezing of nauplii in comparison to eggs or protozoeae. Successful preliminary results in cryopreservation of spermatozoa of P. vannamei, will facilitate preservation of genetic specific to some extent.
6
Hefetz, Abraham, and Justin O. Schmidt. Use of Bee-Borne Attractants for Pollination of Nonrewarding Flowers: Model System of Male-Sterile Tomato Flowers. United States Department of Agriculture, October 2003. http://dx.doi.org/10.32747/2003.7586462.bard.
Full textAbstract:
The use of bee natural product for enhancing pollination is especially valuable in problematic crops that are generally avoided by bees. In the present research we attempted to enhance bee visitation to Male Sterile (M-S) tomato flowers generally used in the production of hybrid seeds. These flowers that lack both pollen and nectar are unattractive to bees that learn rapidly to avoid them. The specific objects were to elucidate the chemical composition of the exocrine products of two bumble bee species the North American Bombus impatiens and the Israeli B. terrestris. Of these, to isolate and identify a bee attractant which when sprayed on M-S tomato flowers will enhance bee visitation, and to provide a procedure of the pheromone application regime. During the research we realized that our knowledge of B. impatiens is too little and we narrowed the objective to learning the basic social behavior of the bees and the pattern of foraging in a flight chamber and how it is affected by biogenic amines. Colonies of B. impatiens are characterized by a high number of workers and a relatively small number of queens. Size differences between queens and workers are pronounced and the queen seems to have full control over egg laying. Only about 9% of the workers in mature colonies had mature oocytes, and there were no signs of a "competition phase" as we know in B. terrestris. Queens and workers differ in their exocrine bouquet. Queen's Dufour's gland possesses a series of linear, saturated and unsaturated hydrocarbons whereas that of workers contains in addition a series of wax-type esters. Bees were trained to either visit or avoid artificially scented electronic flowers in a flight chamber. Since bee also learned to avoid scented non-rewarding flowers we attempted to interfere with this learning. We tested the effect of octopamine, a biogenic amine affecting bee behavior, on the choice behavior of free-flying bumblebees. Our results show that octopamine had no significant effect on the bees' equilibrium choice or on the overall rate of the behavioral change in response to the change in reward. Rather, octopamine significantly affected the time interval between the change in reward status and the initiation of behavioral change in the bee. In B. terrestris we studied the foraging pattern of the bees on tomato flowers in a semi commercial greenhouse in Yad Mordechai. Bee learned very quickly to avoid the non- rewarding M-S flowers, irrespective of their arrangement in the plot, i.e., their mixing with normal, pollen bearing flowers. However, bees seem to "forget" this information during the night since the foraging pattern repeats itself the next morning. Several exocrine products were tested as visitation enhancers. Among these, tarsal gland extracts are the most attractive. The compounds identified in the tarsal gland extract are mostly linear saturated hydrocarbons with small amounts of unsaturated ones. Application was performed every second day on leaves in selected inflorescences. Bee visitation increased significantly in the treated inflorescences as compared to the control, solvent treated. Treatment of the anthers cone was more effective than on the flower petals or the surrounding leaves. Methanol proved to be a non-flower-destructive solvent. We have shown that bumble bees (B. terrestris) can be manipulated by bee-borne attractants to visit non-rewarding flowers. We have further demonstrated that the bees learning ability can be manipulated by applying exogenously octopamine. Both methods can be additively applied in enhancing pollination of desired crops. Such manipulation will be especially useful in tomato cultivation for hybrid seed production.
7
Direct aromatization of methane. Quarterly technical progress report Number 5, 1 October 1993--31 December 1993. Office of Scientific and Technical Information (OSTI), February 1994. http://dx.doi.org/10.2172/10151012.
Full text
8
Commercial-scale demonstration of the Liquid Phase Methanol process. Technical progress report number 8, April 1--June 30, 1996. Office of Scientific and Technical Information (OSTI), December 1996. http://dx.doi.org/10.2172/569049.
Full text
9
Commercial-scale demonstration of the Liquid Phase Methanol (LPMEOH{trademark}) process. Technical progress report number 9, July 1--September 30, 1996. Office of Scientific and Technical Information (OSTI), June 1997. http://dx.doi.org/10.2172/569014.
Full text
10
Commercial-scale demonstration of the Liquid Phase Methanol (LPMEOH{trademark}) process. Technical progress report number 6, October 1--December 31, 1995. Office of Scientific and Technical Information (OSTI), December 1996. http://dx.doi.org/10.2172/569047.
Full text