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101.
The analysis of multiphase flow in porous media is of considerable significance in the field of petroleum reservoir simulation, where accurate predictions of fluid flow are important in assessing the performance of oil and gas fields. The specific case of two-phase immiscible flow is considered by first deriving the governing nonlinear partial differential equations. The space discretization is then carried out making use of the additional versatility of the finite element method compared with originally used finite differences. By using a pair of dependent variables P and R, the bandwidth of the discrete space-continuous time equations may be reduced to increase significantly the speed of the algorithm. A discussion of time-stepping methods is followed by an application of the technique to a five-spot,an extraction pattern used in the field. The boundary conditions used to simulate this flow pattern are also discussed. 相似文献
102.
We consider a tier of weakened bonds along the center line of a two-dimensional Ising ferromagnet strip as a model of a grain boundary. When an interface traverses such a strip at an angle, whether or not there is a continuous pinning-depinning transition at subcritical temperature depends on this angle and the degree of bond weakening. We also study the relaxation of such a system to its equilibrium state using continuous time Monte Carlo simulation with Kawasaki dynamics; this reveals a matter transport mechanism confined to the grain boundary. 相似文献
103.
Nickel A Maruyama T Tang H Murphy PD Greene B Yusuff N Wood JL 《Journal of the American Chemical Society》2004,126(50):16300-16301
A total synthesis of the biologically important diterpene ingenol has been completed. Ring-closing olefin metathesis was used to construct the strained "inside-outside" tetracyclic skeleton, and a series of diastereoselective reactions were employed to complete the synthesis. Another naturally occurring ingenane, 20-deoxyingenol, has also been prepared. 相似文献
104.
Pattison LK Cullen DM Smith JF Fletcher AM Walker PM El-Masri HM Podolyák Z Wood RJ Scholey C Wheldon C Mukherjee G Balabanski D Djongolov M Dalsgaard T Thisgaard H Sletten G Kondev F Jenkins D Lane GJ Lee IY Macchiavelli AO Frauendorf S Almehed D 《Physical review letters》2003,91(18):182501
Evidence is presented for multiphonon excitations based on a high-spin (25 Planck) intrinsic state in the deformed nucleus 182 Os. Angular momentum generation by this mode competes with collective rotation. The experimental data are compared with tilted-axis cranking calculations, supporting the vibrational interpretation. However, the lower experimental energies provide evidence that more complex interactions of states are playing a role. 相似文献
105.
Silvestri MA Miles D Rothwell AP Wood KV Cushman M 《Rapid communications in mass spectrometry : RCM》2003,17(15):1703-1708
Electrospray ionization (ESI) mass spectrometry was employed to obtain both molecular weight confirmation and structural information for a series of novel alkenyldiarylmethane (ADAM) analogs. The mass spectral data were intended for use during the structure elucidation of ester hydrolysis products formed during an in vitro metabolism study of a series of novel ADAM analogs. The data on the precursor molecules show the presence of the molecular ion peak, [M+H](+), as well as a peak consistent with the hydrolysis product of the original ester ([MH-ROH+H(2)O](+)). However, chemical ionization mass spectrometry, elemental analysis and (1)H NMR data indicated the presence of only the intact diester compounds, suggesting that the formation of the hydrolysis product was an instrumental artifact, i.e., in-beam hydrolysis during ESI or a result of longer ion residence times of the ion trap mass analyzer. 相似文献
106.
Wood ME Cane-Honeysett DJ Dowle MD Coles SJ Hursthouse MB 《Organic & biomolecular chemistry》2003,1(17):3015-3023
Methods have been developed for the N-alkylation of 1,2,4-dithiazolidine-3,5-dione 2 and the subsequent conversion of the N-alkylated derivatives into isocyanates 5. An extension of this methodology onto a solid-support is also reported. X-ray crystallographic analysis has been carried out on potassium 1,2,4-dithiazolidine-3,5-dione 3 for structural comparison with the parent heterocycle 2. 相似文献
107.
Chung P Ajitanand NN Alexander JM Anderson M Best D Brady FP Case T Caskey W Cebra D Chance JL Cole B Crowe K Das A Draper JE Gilkes ML Gushue S Heffner M Hirsch AS Hjort EL Huo L Justice M Kaplan M Keane D Kintner JC Klay J Krofcheck D Lacey RA Lauret J Lisa MA Liu H Liu YM McGrath R Milosevich Z Odyniec G Olson DL Panitkin SY Pinkenburg C Porile NT Rai G Ritter HG Romero JL Scharenberg R Schroeder L Srivastava B Stone NT Symons TJ Wienold T Witt R Whitfield J Wood L Zhang WN;E Collaboration 《Physical review letters》2001,86(12):2533-2536
Directed flow measurements for Lambda hyperons are presented and compared to those for protons produced in the same Au+Au collisions (2A, 4A, and 6A GeV; b<5-6 fm). The measurements indicate that Lambda hyperons flow consistently in the same direction but with smaller magnitudes. A strong positive flow [for Lambdas] has been predicted in calculations which include the influence of the Lambda-nucleon potential. The experimental flow ratio Lambda/p is in qualitative agreement with expectations (approximately 2/3) from the quark counting rule at 2A GeV but is found to decrease with increasing beam energy. 相似文献
108.
This paper describes the design and testing of a flow-through ultrasonic separation device that allows the concentration of particles within a fluid. The device operates without the use of an acoustically transparent element. Three models are used to examine the behaviour of the cell, dealing with acoustic-particle interaction, electro-acoustic characteristics, and fluid flow. The device is able to concentrate up to 84% of the 60 microns sand particles in the 'dirty' stream, 13% in the intermediate stream and 3% in the 'clean' stream. Flow rates of up to 20 lh-1 (equating to an inlet velocity of 10(-2) ms-1) have been used with an electrical power input of up to 50 W (10 kWm-1). 相似文献
109.
Cinabro D Henderson S Liu T Saulnier M Wilson R Yamamoto H Bergfeld T Eisenstein BI Gollin G Ong B Palmer M Selen M Thaler JJ Sadoff AJ Ammar R Ball S Baringer P Bean A Besson D Coppage D Copty N Davis R Hancock N Kelly M Kwak N Lam H Kubota Y Lattery M Nelson JK Patton S Perticone D Poling R Savinov V Schrenk S Wang R Alam MS Kim IJ Nemati B O'Neill JJ Severini H Sun CR Zoeller MM Crawford G Daubenmier CM Fulton R Fujino D Gan KK Honscheid K Kagan H Kass R Lee J Malchow R Morrow F Skovpen Y 《Physical review letters》1994,72(10):1406-1410
110.
Gerald Midgley Robert Y. Cavana John Brocklesby Jeff L. Foote David R.R. Wood Annabel Ahuriri-Driscoll 《European Journal of Operational Research》2013
Operational researchers and social scientists often make significant claims for the value of systemic problem structuring and other participative methods. However, when they present evidence to support these claims, it is usually based on single case studies of intervention. There have been very few attempts at evaluating across methods and across interventions undertaken by different people. This is because, in any local intervention, contextual factors, the skills of the researcher and the purposes being pursued by stakeholders affect the perceived success or failure of a method. The use of standard criteria for comparing methods is therefore made problematic by the need to consider what is unique in each intervention. So, is it possible to develop a single evaluation approach that can support both locally meaningful evaluations and longer-term comparisons between methods? This paper outlines a methodological framework for the evaluation of systemic problem structuring methods that seeks to do just this. 相似文献