Long life, low cost ball valve, with lifted seals and cartridge type construction

Ball valve design incorporates modular construction in easy-to-install, easy-to-replace cartridge housing, and a system of cams to lift upstream and downstream seals away from the ball during rotation. Tests conducted on nitrogen tetroxide prove new valve to be more efficient than previous models in preventing leakage

B\u27ars and Catamounts: A Study of Davy Crockett through Genre and Medium

This project seeks to investigate and discuss the changes and variations that have occurred to the mythology of David Crockett over the course of time. Initially appearing as a literary character in 1833, the likeness of Crockett has appeared in a myriad of different texts including: biographies, almanacs, plays, dime novels, comics, television shows, and films. The project attempts to discern how these different iterations of medium and genre altered the mythology of David Crockett. In order to methodologically understand these changes, this project makes use of W.T. Lhamon’s concept known as the Lore Cycle. Lhamon identified that lore diffuses through culture cyclically: the nascent stages of a lore occur as a construct of basic capital, but over time is assumed and promulgated by industrial capital. Overall, this project identified three distinct lore cycles that pertain to Crockett: the first begins during Crockett’s lifetime, the second occurs after Crockett’s death and continues through the nineteenth century, and the last cycle identified occurs in the twentieth century. The initial lore cycle produces a mythology that promotes the ideals of American Exceptionalism. Crockett’s story bolsters early American myths in order to create a sense of unified identity. The second cycle relies upon these underlying myths in order to modify Crockett’s mythology into a social and economic regulator. Finally, the last cycle identified utilizes Crockett as a means of instilling conservative ideals. Fully assumed by corporate entities, Crockett’s likeness is utilized to restore order in a tumultuous century

Теоретична сутність та складові механізму логістичного управління ресурсним забезпеченням силових структур

Розглянута сутність та визначені складові механізму логістичного управління ресурсним забезпеченням силових структур. Запропоновані показники оцінювання ефективності механізму управління.Considered essence and the constituents of mechanism of logistic management the resource providing of power structures are certain. Offered indexes of evaluation of efficiency of mechanism of management

Experimental and modeling study of the autoignition of 1-hexene/iso-octane mixtures at low temperatures

Autoignition delay times have been measured in a rapid compression machine at Lille at temperatures after compression from 630 to 840 K, pressures from 8 to 14 bar, \Phi = 1 and for a iso octane/1 hexene mixture containing 82% iso-octane and 18% 1 hexene. Results have shown that this mixture is strongly more reactive than pure iso-octane, but less reactive than pure 1 hexene. It exhibits a classical low temperature behaviour, with the appearance of cool flame and a negative temperature coefficient region. The composition of the reactive mixture obtained after the cool flame has also been determined. A detailed kinetic model has been obtained by using the system EXGAS, developed in Nancy for the automatic generation of kinetic mechanisms, and an acceptable agreement with the experimental results has been obtained both for autoignition delay times and for the distribution of products. A flow rate analysis reveals that the crossed reactions between species coming from both reactants (like H-abstractions or combinations) are negligible in the main flow consumption of the studied hydrocarbons. The ways of formation of the main primary products observed and the most sensitive rate constants have been identified

Experimental investigation of the intermediates of isooctane during ignition

Direct measurements of intermediates of ignition are challenging experimental objectives, yet such measurements are critical for understanding fuel decomposition and oxidation pathways. In the current work, a new gas-sampling system is used to provide quantitative discrete measurements of 30 hydrocarbon and oxygenate species during rapid compression facility studies of isooctane ignition. Two target conditions and equivalence ratios (based on molar fuel to oxygen ratio) were studied (P = 5.2 atm, T = 1000 K, φ = 0.4 and P = 4.8 atm, T = 975 K, φ = 1.2). The results are compared with model predictions that use the detailed reaction mechanism developed by Curran et al. ( Combust Flame 2002, 129, 253–280). In general, the model predictions are in excellent agreement with the experimental data, including several trace species. Isobutene (i-C 4 H 8 ) and propene (C 3 H 6 ) were the major olefin species identified in the experiments. The results are consistent with an intermediate temperature reaction path sequence, where isooctane is consumed by H-atom abstraction to yield isooctyl radicals that undergo Β-scission to form olefin and alkyl radical species. © 2007 Wiley Periodicals, Inc. Int J Chem Kinet 39: 498–517, 2007Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/56133/1/20254_ftp.pd

The competing chemical and physical effects of transient fuel enrichment on heavy knock in an optical spark ignition engine

The work was concerned with improving understanding of the chemical and physical trade-offs when employing transient over-fuelling to control auto-ignition in gasoline spark ignition engines under knock intensities not usually tolerated in optical engines. The single cylinder engine used included full bore overhead optical access capable of withstanding unusually high in-cylinder pressures. Heavy knock was deliberately induced by adopting inlet air heating and a primary reference fuel blend of reduced octane rating. High-speed chemiluminescence imaging and simultaneous in-cylinder pressure data measurement were used to evaluate the combustion events. Under normal operation the engine was operated under port fuel injection with a stoichiometric air-fuel mixture. Multiple centred auto-ignition events were regularly observed, with knock intensities of up to ~30bar. Additional excess fuel was then introduced directly into the end-gas in short transient bursts. As the mass of excess fuel was progressively increased a trade-off was apparent, with knock intensity first increasing by up to 65% before lower unburned gas temperatures suppressed knock under extremely rich conditions. This trade-off is not usually observed during conventional low intensity knock suppression via over-fuelling and has been associated with the competing effects of reducing auto-ignition delay time and charge cooling/ratio of specific heats. Overall, the results demonstrate the risks in employing excess fuel to suppress knock deep within a heavy knocking combustion regime (potentially including a Super-Knock regime)