1,936 research outputs found

    Gas field scheduling

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    Woodside Offshore Petroleum is the operator in the development of new gas fields in Australia's North West Shelf project. Sequencing the development of new gas fields in this project is a key determinant of its return on investment. This development sequence has constraints imposed by infrastructure and contractual obligations as well as natural features. The determination of an optimal or very good solution may involve a number of techniques from operations research. The study group attempted several approaches to the problem, principal amongst them being mathematical programming and dynamic programming. A few other heuristic approaches were also considered. The mathematical programming approach was able to yield solutions to small instances of the problem. The group was able to identify several avenues for further research and work on the problem is ongoing

    The use of honey in healing a recalcitrant wound following surgical treatment of hidradenitis suppurativa

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    Ancient civilizations used honey to heal wounds. Despite the rediscovery of honey by modern physicians1 its use in conventional medicine, unlike in complementary medicine, remains limited. Much anecdotal evidence, some clinical observations, some animal models and some randomised controlled trials support the efficacy of honey in managing wounds2,3 , but few detailed descriptions of the use of honey in healing difficult surgical wounds have previously been published

    Studies on the electron transfer pathway, topography of iron-sulfur centers, and site of coupling in NADH-Q oxidoreductase.

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    Electron transfer activities and steady state reduction levels of Fe-S centers of NADH-Q oxidoreductase were measured in mitochondria, submitochondrial particles (ETPH), and complex I after treatment with various reagents. p-Chloromercuribenzenesulfonate destroyed the signal from center N-4 (gx = 1.88) in ETPH but not in mitochondria, showing that N-4 is accessible only from the matrix side of the inner membrane. N-Bromosuccinimide also destroyed the signal from N-4 but without inhibiting rotenone-sensitive electron transfer to quinone, suggesting a branched pathway for electron transfer. Diethylpyrocarbonate caused oxidation of N-3 and N-4 in the steady state without changing N-1, suggesting N-1 is before N-3 and N-4. Difluorodinitrobenzene and dicyclohexylcarbodiimide inhibited oxidation of all Fe-S centers and tetranitromethane inhibited reduction of all Fe-S centers. Titrations of the rate of superoxide (O2-) generation in rotenone-treated submitochondrial particles were similar with the ratio [NADH]/[NAD] and that of 3-acetyl pyridine adenine nucleotide in spite of different midpoint potentials of the two couples. On reaction with inhibitors the inhibition of O2- formation was similar to that of ferricyanide reductase rather than quinone reductase. The rate of O2- formation during ATP-driven reverse electron transfer was 16% of the rate observed with NADH. The presence of NAD increased the rate to 83%. The results suggest that bound, reduced nucleotide, probably E-NAD., is the main source of O2- in NADH dehydrogenase. The effect of ATP on the reduction levels of Fe-S centers in well-coupled ETPH was measured by equilibrating with either NADH/NAD or succinate/fumarate redox couples. With NADH/NAD none of the Fe-S centers showed ATP induced changes, but with succinate/fumarate all centers showed ATP-driven reduction with or without NAD present. The effect on N-2 was smaller than that on N-1, N-3, and N-4. These observations indicate that the major coupling interaction is between N-2 and the low potential centers, N-1, N-3, and N-4. Possible schemes of coupling in this segment are discussed

    Biological Suppression of Major Mealybug Species on Horticultural Crops in India

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    Mealybugs, known to be 'hard to kill pests', live in protected areas and most stages in their life cycle are covered in a waxy coating. Several insecticides are found ineffective against mealybugs. Fortunately, mealybugs - being sessile insects - are more amenable to biological control. The exotic parasitoid, Leptomastix dactylopii How., was found to be highly effective in suppressing citrus mealybug, Planococcus citri (Risso.) permanantly on citrus, sapota, guava, pomegranate and coffee. This is one of the recent successes in classical biological control attempts in India. However, the Australian ladybird beetle, Cryptolaemus montrouzieri Muls., often provides spectacular control of heavy infestation of P. citri on acid lime, lemon, sweet orange, pummelo, Crossandra and custard apple. Though Anagyrus dactylopii (How.), is a potential parasitoid of pink hibiscus mealybug, Maconellicoccus hirsutus (Green), on grapes, releases of C. montrouzieri only help in suppression of the pink hibiscus mealybug on grapes, ber, guava, sapota, custard apple, citrus and hibiscus. The encyrtid parasitoid, Tetracnemoidea indica (Ayyar), was able to check the oriental mealybug, Planococcus lilacinus (Ckll.) on acid lime and pomegranate. The predators, C. montrouzieri and Spalgis epeus Westwood, also play a major role in suppression of P. lilacinus on guava, ber, sapota and chow-chow. The local parasitoid, A. dactylopii was seen to play a major role in suppression of spherical mealybug, Nipaecoccus viridis (Maskell) on citrus and jackfruit. Nevertheless, releases of C. montrouzieri are found highly effective in controlling N. viridis on acid lime and pummelo. Similarly release of C. montrouzieri is found to be highly effective in controlling striped mealybug, Ferrisia virgata (Ckll.), on guava, tuberose and Acalypha in 30-40 days of release. A local parasitoid, Aenasius advena Comp., also plays a major role in suppression of F. virgata on guava, mango, guava, hibiscus, fig, citrus, etc. Release of the coccinellid predator, C. montrouzieri, was found very effective in controlling the mango coccid, Rastrococcus iceryoides (Green) on mango and also on the medicinal plant Decalepis hamiltonii. The encyrtid, Praleurocerus viridis (Agarwal), was found very effective in reducing populations of R. iceryoides on guava. Spalgis epeus was found to be the predominant predator of the papaya mealybug, Paracoccus marginatus Williams and de Granara Willink, but releases of the exotic parasitoid, Acerophagus papayae(Noyes&Schauff), only provide excellent control of P. marginatus within 3-4 months of release. The second successful classical biological control attempt on mealybugs in India. The brinjal mealybug, Coccidohystrix insolita (Green), is known to attack brinjal, Coleus, Hibiscus, etc. Cryptolaemus montrouzieri effectively controlled mealybugs on these three crops in 30-40 days of release. Verticillium lecanii Zimm. (Phule bugicide @ 2g/L) is found to be effective in killing the mealybug. Other fungal pathogens, viz., Beauveria bassiana (Bals.) Vuill and Metarhizium anisopliae (Metch.), are also seen to infect mealybugs in rainy season under humid conditions

    Maximal Class Numbers of CM Number Fields

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    Fix a totally real number field F of degree at least 2. Under the assumptions of the generalized Riemann hypothesis and Artin\u27s conjecture on the entirety of Artin L-functions, we derive an upper bound (in terms of the discriminant) on the class number of any CM number field with maximal real subfield F. This bound is a refinement of a bound established by Duke in 2001. Under the same hypotheses, we go on to prove that there exist infinitely many CM-extensions of F whose class numbers essentially meet this improved bound and whose Galois groups are as large as possible

    EXPERIMENTAL STUDY ON SELFCOMPACTING CONCRETE CONTAINING INDUSTRIAL BY-PRODUCTS

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    Self-Compacting Concrete (SCC) is a type of concrete that has thecapacity to consolidate under its own weight. The current trend all over theworld is to utilize the treated and untreated industrial by-products, domesticwaste etc. as a raw material in concrete, which gives an eco-friendly edge tothe concrete preparation process. This practice not only helps in reuse of thewaste material but also creates a cleaner and greener environment. This studyaims to focus on the possibility of using industrial by-products like GroundGranulated Blast furnace Slag (GGBS) and Silica fumes (SF) in preparationof SCC. The usage of these powders is proposed as a replacement for cementin the production of SCC by adopting the much popular Nan Su et al. methodof mix design. The paper deals with comparison of performances of GGBSand SF based SCC mixes

    Classical Simulation of One-Query Quantum Distinguishers

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