蠕变条件下完整岩石的起裂和扩展准则

The mechanism and criterion of crack initiation and propagation of rocks were investigated by many researchers,And the creep behaviour of rocks was also theoretically and experimentally studied by some scientists and engineers.The characteristics of crack initation and propagation of rocks under creep condition.however,are very improtant for rock engineering and still not paid enough attention by researchers,In this paper,the criterion and mechanism of crack initiation and propagation under creep condition were investigated using specimens collected from sandstone rock formations outcropping in the Emei Mountain,the Sichuan Province of China.Cuboid specimens under three point bending were used in this investigation.All specimens were classified into four sorts and used for Mode-I fracutre of creep frcture tests.The experimental result shows that due to creep deformation.rock crack will inevitably initialt and propagate under a load of KI,which is less than fracture toughness KIC but not less than a constant(marked as KIC2),KIC2 indicates the ability of rock to resist crack initiation and propagation under creep conditions and is less than fracture tough ness KIC.defined as creep fracture toughness in this paper,KIC2 should be considered as an importnat parameter on design and computation of rock engineering.The microstructureal mechanism for crack initiation and propagation of rock materials under creep condition was introduced based on competitive model between softening effect and hardening effect,and the validity of test result was explained.The test result was also verified in rheological theory.When KI is more than KIC2 but less than KIC,rock crack will initiate and propagate after a time interval of sustained loading under creep condition.In order to find the relation between duration of sustained lading.which can lead to crack initiation and propagation,and the initial stress intensity factor KI,an unequal0interval time sequence forecasting and predicting model was introduced,and the relation was obtained for homogeneous and isotropic fine-grained red sandstone.Finally a modified fracture toughness formula was given,in which the influence of fracture process zone(FPZ) was fully considered.     

Adopting a toolkit to manage time,resources, and expectations in the systematic review process: a case report

Background:The proliferation of systematic reviews has impacted library operations and activities as librarians support, collaborate, and perform more tasks in the systematic review process. This case report describes a toolkit that librarians with extensive experience in supporting multiple review teams use to manage time, resources, and expectations in the systematic review process.Case Presentation:The toolkit is a compilation of documents that we use to effectively communicate with and help review teams understand and navigate each stage of the systematic review process. Elements included in the toolkit and discussed in this case report are intake forms, communication templates and memoranda, a process flow diagram, library guides on tools for retrieval and data appraisal, and established standards for guidance during the write-up stage. We describe the use of the toolkit for both education and project management, with a focus on its use in helping manage team time, resources, and expectations.Discussion:The systematic review toolkit helps librarians connect systematic review steps and tasks to actionable items. The content facilitates and supports discussion and learning by both librarians and team members. This toolkit helps librarians share important information and resources for each stage of the process.     

Sprint and jump performances do not determine the promotion to professional elite soccer in Spain, 1994–2012

ABSTRACT

The aims of this study are (a) to describe the evolution of neuromuscular performance over an 18 year period within a Spanish elite reserve team; (b) to check if there were any relation between the playing position and sprint and jump performances and (c) to look into the alleged impact of this factor on the top playing level attained by the soccer players. We considered the physical tests (5 m and 15 m sprint times and countermovement jump (CMJ) height) made by 235 players enrolled in the reserve team of the Club from 1994 to 2012 and the highest competitive-level they achieved: Spanish first (n = 39) and second divisions (n = 36) and semi-professional (n = 160). Furthermore, the players were classified according to their playing positions. The main findings were a very-likely/most-likely lower neuromuscular performance (ES = 0.48–0.68, small to moderate) in the last six-season term (2006–2012) than in the first term (1994–2000); possibly/very-likely lower performances in sprinting and CMJ (ES = 0.22–0.55, small) by central defenders (CDs) and midfielders than by other playing positions; very-likely better performances in sprinting and jumping by first and second divisions central defenders than by semi-professional central defenders (ES = 0.90–1.02, moderate). Sprint and jump performances are not a relevant physical parameter to promote to the top level of soccer in Spain except for one in six of the playing positions: CDs.     

Attachment relationships and adolescents' life satisfaction: Some relationships matter more to girls than boys

This study examined the extent to which the quality of parent and peer attachments related to early adolescents' life satisfaction (LS), whether peer attachment served as a mediator between parent attachment and LS, and potential gender differences. A total of 587 middle school students in grades 6 through 8 participated. Although both parent and peer attachment positively related to LS, parent attachment was the stronger unique predictor. There was no significant difference between males and females in levels of parent attachment; however, females reported higher levels of attachment to peers. This study also found that early adolescents were more attached to their mothers than their fathers. Finally, peer attachment partially mediated the relationship between parent attachment and LS, but only for females. Implications for gender‐specific intervention programs are discussed. © 2008 Wiley Periodicals, Inc.     

The Self‐evaluation of Teachers: a Strategy for the Improvement of Teaching at Higher Education Level

Teaching assessment at higher education level is required in order to improve the quality of teaching in universities. As both teaching staff and students are equally involved in the teaching/learning process, the views of both must be taken into account when determining the quality of teaching. Basically, a self‐evaluation process has two aspects. On the one hand, there is the source of information, the teacher in this particular case. He or she has the opportunity to reflect upon the actual teaching situation by evoking his or her own point of view in regard to his or her vision of reality even if it might be judged as a complementary view as opposed to other views. On the other hand, the objective of the process might be one either of providing a means of checking (process evaluation) or of improving (result evaluation). A detailed analysis of the two characteristics will enable us to appreciate properly their inter‐connectedness. This analysis, as well as the prior experience of the authors in the domain of teaching assessment within their university, enables them to present a model of self‐evaluation applicable to the context in which they are working.     

Participatory principles in human inquiry: ethics and methods in a study of the paradigm shift experience

In this paper, underlying principles for guiding participation in human science research are outlined. These research principles were originally utilized as a guiding framework for the author's phenomenological study of the change to a new world‐view identified as the paradigm shift (Dudley, 1987). Using this study as an example, the paper focuses on the integration of participatory concepts in research. The concept of participation as ethics discussed in this paper includes the following dimensions: integrity congruence among problem, paradigm, and method; process‐orientation a commitment to research as a shared journey of discovery; empathetic relationships an ethic of mutuality; and empowerment in community a view of knowledge as communal achievement. Finally, a participatory ethic is discussed in terms of its congruence with values that are at the heart of the new social science paradigm.     

Microcomputer Integration into a Special Education Institute in Bahrain: A Pilot Project

Abstract

The purpose of this paper is to discuss the introduction of microcomputers into the Hope Institute, a school for mildly mentally retarded children. Readily available software in English could not be implemented, hence software had to be specially written for this pilot project. The package was demonstrated to the officials concerned at the Institute and was well received. It is expected that the growing awareness about the use of computers in the secondary schools of Bahrain will reinforce the results of our experiment and promote the introduction of computers into the special education institutes of the country.     

新升本科院校内部控制制度建设初探

高校的内部控制建设是一个新的课题,是高校提高综合办学实力和社会竞争力的必要手段,在高校管理中的作用越来越重要,建立和完善高校内部控制制度已势在必行。针对新升本科院校内部控制存在的意识淡薄、制度不健全、缺乏风险控制意识等问题进行了分析探讨,提出了相关建议及措施。