A feasibility study for reset control of an industrial batch reactor

Includes abstract.Includes bibliographical references (leaves 128-133).A feasibility study for the application of reset control to the temperature control loop of a pressurized exothermic batch leach reactor in the hydrometallurgical Precious Group Metals (PGM) industry is carried out. Keywords: Reset control; Clegg integrator; initial states; industrial batch reactor; temperature control; exothermic reactions; multiple reactions; dissolve; leach; hydrometallurgy; platinum; Precious Group Metals (PGMs)

He Scattering from Compact Clusters and from Diffusion-Limited Aggregates on Surfaces: Observable Signatures of Structure

The angular intensity distribution of He beams scattered from compact clusters and from diffusion limited aggregates, epitaxially grown on metal surfaces, is investigated theoretically. The purpose is twofold: to distinguish compact cluster structures from diffusion limited aggregates, and to find observable {\em signatures} that can characterize the compact clusters at the atomic level of detail. To simplify the collision dynamics, the study is carried out in the framework of the sudden approximation, which assumes that momentum changes perpendicular to the surface are large compared with momentum transfer due to surface corrugation. The diffusion limited aggregates on which the scattering calculations were done, were generated by kinetic Monte Carlo simulations. It is demonstrated, by focusing on the example of compact Pt Heptamers, that signatures of structure of compact clusters may indeed be extracted from the scattering distribution. These signatures enable both an experimental distinction between diffusion limited aggregates and compact clusters, and a determination of the cluster structure. The characteristics comprising the signatures are, to varying degrees, the Rainbow, Fraunhofer, specular and constructive interference peaks, all seen in the intensity distribution. It is also shown, how the distribution of adsorbate heights above the metal surface can be obtained by an analysis of the specular peak attenuation. The results contribute to establishing He scattering as a powerful tool in the investigation of surface disorder and epitaxial growth on surfaces, alongside with STM.Comment: 41 pages, 16 postscript figures. For more details see http://www.fh.huji.ac.il/~dan

Anisotropic atomic motions in structural analysis by low energy electron diffraction

The structure of the √3 × √3 R30° overlayer formed by CO molecules adsorbed on a Ru(0001) was analyzed by low energy electron diffraction. Anisotropic atomic motions under the influence of thermal excitation were taken into account by adopting the concept of split positions. Apart from considerable improvement in the structural refinement this technique provides information about dynamic processes. In particular, the molecular axis of the CO molecules was found to be tilted on the average by (12±3° at 150 K, which is attributed to excitation of the bending mode vibration (i.e., frustrated translation)

Unit Operation and Unitization in Arkansas, Louisiana, Texas and New Mexico

Questionnaires and special letters soliciting information were sent to agreat many geologists, petroleum engineers, independent operators, andrepresentatives of large companies in Arkansas, Louisiana, Texas and NewMexico. Replies to more than 50 percent of these letters were received. Asurvey of the facts and opinions presented in this correspondence will be madea little later, but first some of the general aspects of the problem will bereviewed. By "unit operation," we mean the development and operation of a singleentire pool, or reservoir, of petroleum by one management, on a systematic andscientific plan which is best calculated ultimately to extract from the paysand and bring to the surface of the ground the largest possible amount of oilwith the greatest possible total profit. No one, as far as the author has been able to ascertain, denies the advantages, both scientific and practical, of unit operation. All are agreed that it issound in theory. It permits the proper distribution of wells, which shouldalways be spaced on the ground according to a regular geometric plan with theintention of maintaining the same spacing all the way down and into the paysand, or pay sands. This spacing will be different for different fields, depending on such variable factors as the lithologic character of the payformation, the nature of the controlling structure, the depth of drilling, theviscosity of the oil, and so on. From the viewpoint of engineering practice, asapplied to economical extraction of oil,! there is no more importantconsideration than well spacing-well spacing in the pay formation, and notmerely on the surface 'of the ground -for the method of well spacing has adirect bearing upon all such engineering practices as pressure control, repressuring by gas, the water drive, and so on.</jats:p

Betty o’ Yep’s Laughable Tale of Jinny Cropper at th’ Halton Feast

Literatura dialectal inglesa.-- Lancashire.-- Pertenece a la colección 1800-1950 del Salamanca Corpus.-- Prosa.-- Margaret R. Lahee.-- Betty o' Yep's Laughable Tale. -- 1865.-- Primera edición.[EN] Prose work written in the Lancashire dialect. [ES] Obra en prosa escrita en el dialecto de Lancashire

Letter to H.B. Stenzel from F.H. Lahee on 1940-12-09

Jackson School of Geoscience