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To simulate the kinematics associated with mining‐induced subsidence in a blocky rock mass, a hybrid rigid block model was developed by combining a small displacement code…
To simulate the kinematics associated with mining‐induced subsidence in a blocky rock mass, a hybrid rigid block model was developed by combining a small displacement code with a large displacement code. Gravity was applied to a rigid block mesh using an implicit formulation and the equilibrium displacements are then used as initial conditions for an explicit analysis in which excavation of a longwall mine panel and subsequent subsidence was simulated. A parameter study was performed to evaluate the influence of rigid block contact stiffness, vertical joint density, and contact roughness on mining‐induced strata movements for comparison with previously obtained field measurements. The best agreement between measured and calculated displacements was obtained when a relatively low stiffness value was maintained constant for all contacts. A surprising result was that neither increasing the density of vertical joints nor reducing the rigid block contact roughness improved the agreement between measured and simulated displacements.
The purpose of this paper is to assess the effect of the statical admissibility of the recovered solution and the ability of the recovered solution to represent the…
The purpose of this paper is to assess the effect of the statical admissibility of the recovered solution and the ability of the recovered solution to represent the singular solution; also the accuracy, local and global effectivity of recovery‐based error estimators for enriched finite element methods (e.g. the extended finite element method, XFEM).
The authors study the performance of two recovery techniques. The first is a recently developed superconvergent patch recovery procedure with equilibration and enrichment (SPR‐CX). The second is known as the extended moving least squares recovery (XMLS), which enriches the recovered solutions but does not enforce equilibrium constraints. Both are extended recovery techniques as the polynomial basis used in the recovery process is enriched with singular terms for a better description of the singular nature of the solution.
Numerical results comparing the convergence and the effectivity index of both techniques with those obtained without the enrichment enhancement clearly show the need for the use of extended recovery techniques in Zienkiewicz‐Zhu type error estimators for this class of problems. The results also reveal significant improvements in the effectivities yielded by statically admissible recovered solutions.
The paper shows that both extended recovery procedures and statical admissibility are key to an accurate assessment of the quality of enriched finite element approximations.
Given the growing interest in social movements as policy agenda setters, this paper investigates the contexts within which movement groups and actors work with political…
Given the growing interest in social movements as policy agenda setters, this paper investigates the contexts within which movement groups and actors work with political elites to promote their common goals for policy change. In asking how and why so-called outsiders gain access to elites and to the policymaking process, I address several contemporary theoretical and empirical concerns associated with policy change as a social movement goal. I examine the claim that movements use a multipronged, long-term strategy by working with and targeting policymakers and political institutions on the one hand, while shaping public preferences – hearts and minds – on the other; that these efforts are not mutually exclusive. In addition, I look at how social movement organizations and actors are critical in expanding issue conflict outside narrow policy networks, often encouraged to do so by political elites with similar policy objectives. And, I discuss actors’ mobility in transitioning from institutional activists to movement and organizational leaders, and even to protesters, and vice versa. The interchangeability of roles among actors promoting social change in strategic action fields points to the porous and fluid boundaries between state and nonstate actors and organizations.
OWING to the comparatively early date in the year of the Library Association Conference, this number of THE LIBRARY WORLD is published so that it may be in the hands of our readers before it begins. The official programme is not in the hands of members at the time we write, but the circumstances are such this year that delay has been inevitable. We have dwelt already on the good fortune we enjoy in going to the beautiful West‐Country Spa. At this time of year it is at its best, and, if the weather is more genial than this weather‐chequered year gives us reason to expect, the Conference should be memorable on that account alone. The Conference has always been the focus of library friendships, and this idea, now that the Association is so large, should be developed. To be a member is to be one of a freemasonry of librarians, pledged to help and forward the work of one another. It is not in the conference rooms alone, where we listen, not always completely awake, to papers not always eloquent or cleverly read, that we gain most, although no one would discount these; it is in the hotels and boarding houses and restaurants, over dinner tables and in the easy chairs of the lounges, that we draw out really useful business information. In short, shop is the subject‐matter of conference conversation, and only misanthropic curmudgeons think otherwise.
The Table which is printed along with this article gives a view of the progress of our Public Libraries as shown by the adoptions of the Acts, year by year, since 1848. In heavier type are set out the various Acts of Parliament or other influences which have had a determining effect in popularizing and spreading the Public Library. We have also added as an item of additional interest, the name of the first librarian of each town, so far as we have been able to ascertain it. But this is not guaranteed to be absolutely correct, and we shall be pleased to have notifications of errors and omissions.
Information and special library work is at present a profession that is in the process of formation and struggling for recognition, and entry into it is entirely…
Information and special library work is at present a profession that is in the process of formation and struggling for recognition, and entry into it is entirely uncontrolled. People with the most varied backgrounds and levels of education find themselves made responsible for setting up or running library and information services, without any previous knowledge of the work. Often they are in remote places and without any contact with more experienced colleagues who could give them advice, and their only means of getting the knowledge necessary for the efficient carrying out of their duties is from reading. But, owing to the unsettled state of the profession, the literature is voluminous and scattered, and much of it is of a low standard, or occupied with pure theorizing or polemics. Moreover, the literature that the novice is most likely to see, namely the articles on documentation which are occasionally printed in technical journals, is not always the most helpful for a person who has no background of experience against which he can evaluate it. In these circumstances the new entrant needs a guide to the literature if he is not to be discouraged or adopt practices and systems which are not really suitable to his circumstances. It is to meet this need that this annual review of the literature, now in its sixth year, has been written. It attempts to select those books and papers which are most likely to be of direct help in running a small information department or library, eschewing all pure theorizing and polemics, and only including literature on large libraries where it is felt that it contains ideas capable of application in smaller organizations. To these are added a selection of the most important works of reference, including some that the information officer may wish to know about and consult in other libraries, even though his own library does not possess them. The list is not restricted to work published in 1957, but is intended to be representative of items received in British libraries during the period under review. Owing to restrictions in space, the selection has to be rigorous, and is inevitably, to a certain extent, a personal one. No two people would probably agree on all the omissions, but it is hoped that all the items included will be of positive value to the type of reader for whom the review is intended.
WHERE are we going? The aim is to double our standard of living in the next 25 years and, as Sir Alexander Fleck, K.B.E., Chairman of Imperial Chemical Industries Ltd., so aptly staled recently, ‘The man who knows where he is going is the one who is most likely to arrive.’ One might venture to expand this statement by adding that he is still more likely to arrive if the cluttering debris of inefficient methods and movements are cleared away.
TO stand above the new Rolls‐Royce Sinfin test plant provokes many assorted thoughts. Here is tradition—the tradition of the British engineer—set forth in acres of intricate machinery. Here is enormous power. And here is the signpost to the future. This vast undertaking shows how great and important are the changes taking place in our time.