An analysis of fretting cracks--II. Unloading and reloading phases

An elastic half-plane containing a surface-breaking crack normal to the free surface, subjected to loading by uniform tractions over a given length of its surface, is considered. The tractions consist of pressure, constant in time, and a shear load, varying sinusoidally in time, both applied adjacent to the crack. This geometry approximates the classical fretting problem with a resulting fatigue crack. The faces of the crack are allowed to transmit Coulomb friction.In this paper it is assumed that the pressure has already been applied, and that the shear traction has been increased continuously from zero to a maximum value. The effect of varying the shear traction through the rest of one load cycle is considered. Stress intensity factors are computed for various crack lengths, friction coefficients, and ratios of applied tractions. The history of stick and slip zones found along the crack faces is monitored.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/26411/1/0000498.pd

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

Subsurface Cracks in Rolling Contact (Fretting).

The present work, motivated by failures in rolling components, gives a more exact treatment of the subsurface crack lying parallel to the surface, subjected to a moving compressive normal surface force and transmitting frictional forces between its faces, than has hereto been presented. In particular, the variations of the maximum value of K(,II) and its range ((DELTA)K(,II)) with the coefficient of friction (f) and the crack length/depth ratio (L/a) are investigated. Also of interest is the influence of possible Mode I action at the two crack tips. The presence of a moving load and crack face friction make the problem history dependent, and one would not necessarily expect equal variation of K(,II) and K(,I) at the two crack tips. Furthermore, this history dependence requires that a modification be made to the well established elasticity-dislocation approach to studying linear elastic contact problems, in order that the problem can be treated incrementally.Ph.D.MechanicsUniversity of Michiganhttp://deepblue.lib.umich.edu/bitstream/2027.42/160593/1/8512505.pd

Research-informed practices for inclusive science, technology, engineering, and math (STEM) classrooms: strategies for educators to close the gender gap. Am Soc Engineering Educ. Retrieved from https://www.stanford.edu/ group/design_education/wikiupload/4

Abstract The underrepresentation and attrition of women students in science, technology, engineering, and math (STEM) fields is a widely acknowledged, complex problem for which solutions will be multi-faceted. However, while a large body of research examines factors that influence girls' and women's experiences in these fields, many STEM educators at the K-12 level may be unfamiliar with the most recent research on gender's relation to STEM classes. This paper aims to bridge research to practice by identifying strategies for educators as they work to capture students' interest in STEM and retain students who are already interested. Seven "key practices" for creating gender-inclusive STEM classrooms were identified through a comprehensive literature review of social science research in gender and education. This research indicates, moreover, that the benefits of most practices can be broadened to all STEM students. The paper begins with an overview of the conceptual and methodological approach to the literature review process, and then presents and discusses the seven practices and supporting research. We then turn to recommending implementation strategies for educators to make courses more inclusive. The strategies are followed by a brief outline of suggested directions for future research

The dynamics of innovation efforts in the early career

Funding Information: The Engineering Majors Survey research program has been supported by the National Science Foundation (grant number 1636442) and the National Center for Engineering Pathways to Innovation (Epicenter), a centre funded by the National Science Foundation (grant number DUE‐1125457). Work for this particular study has also been partially funded by the Fulbright ‐ Technology Industries of Finland Grant, The Finnish Science Foundation for Economics and Technology, and the Foundation for Economic Education and General Motors (through a gift to Stanford University promoting greater diversity and access to STEM fields). We also wish to thank the interviewed engineers for their time, Mathias Klenk for contributing to the data collection, Anna Kuukka for help in visualizing the dynamics and the members of the Designing Education Lab for their feedback throughout the course of the study. Publisher Copyright: © 2022 The Authors. Creativity and Innovation Management published by John Wiley & Sons Ltd.Although innovation is highly valued in organizations, early-career professionals face a paradox of bringing in novel ideas, yet having varied latitude and support to see these new ideas through. Building on 35 critical-incident-based interviews with early-career engineers in the United States, this study illuminates the socially situated dynamics of their innovation efforts, examining the process of such promotive proactive behaviour. We find that all participants reported some engagement in creating, championing and implementing new ideas, typically in the form of self-initiated improvements to the tools and processes participants used in their jobs. Encouragement from direct supervisors, supportive organizational cultures and practices, job scope, time afforded and one's perceived status were key considerations in determining whether to take such initiative. Carrying out innovative work behaviours, in turn, was largely dependent on continued employee initiative and ad hoc, informal cooperation, with individual effort punctuated by influential interactions with others that often determined the perceived valence of efforts. The study adds to understanding the social interactions and perceptions of voice required for innovative work behaviour, revealing when and to whom these prerequisites are afforded. Implications for organizations' innovation capacity and new hires' participation in innovation are discussed.Peer reviewe

Pedagogies of Engagement: Classroom-Based Practices

Educators, researchers, and policy makers have advocated student involvement for some time as an essential aspect of meaningful learning. In the past twenty years engineering educators have implemented several means of better engaging their undergraduate students, including active and cooperative learning, learning communities, service learning, cooperative education, inquiry and problem-based learning, and team projects. This paper focuses on classroom-based pedagogies of engagement, particularly cooperative and problem-based learning. It includes a brief history, theoretical roots, research support, summary of practices, and suggestions for redesigning engineering classes and programs to include more student engagement. The paper also lays out the research ahead for advancing pedagogies aimed at more fully enhancing students' involvement in their learning

Persistence, engagement, and migration in engineering programs

Records from the Multiple-Institution Database for Investigating Engineering Longitudinal Development indicate that engineering students are typical of students in other majors with respect to: persistence in major; persistence by gender and ethnicity; racial/ethnic distribution; and grade distribution. Data from the National Survey of Student Engagement show that this similarity extends to engagement outcomes including course challenge, feculty interaction, satisfaction with institution, and overall satisfaction. Engineering differs from other majors most notahly by a dearth of female students and a low rate of migration into the major. Noting the similarity of students of engineering and other majors with respect to persistence and engagement, we propose that engagement is a precursor to persistence. We explore this hypothesis using data from the Academic Pathways Study of the Center for the Advancement of Engineering Education. Further exploration reveals that although persistence and engagement do not vaiy as much as expected by discipline, there is significant institutional variation, and we assert a need to address persistence and engagement at the institutional level and throughout higher education. Finally, our findings highlight the potendal of making the study of engineering more attractive to qualified students. Our findings suggest that a two-pronged approach holds the greatest potential for increasing the number of students graduating with engineering degrees; identify programming that retains the students who come to college committed to an engineering major, and develop programming and policies that allow other students to migrate in. There is already considerable discourse on persistence, so our findings suggest that more research focus is needed on the pathways into engineering, including pathways from other majors