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

Printed in Great Britain. # 1997 TEMPUS Publications. Examples of Freshman Design Education*

This paper looks at specific examples of how engineering programs around the United States are revising freshman year curricula to include engineering design. It builds on a companion paper [1] which provides a framework for viewing, interpreting and categorizing the various approaches to exposing freshman-level students to key design qualities. Example courses are grouped according to this framework, and similarities and differences in approaches are discussed. The paper goes on to reflect upon some of the challenges that design education, particularly at the freshman level, present to instructors and students. These include needs for: re-evaluating the role of instructor; re-evaluating the role of students; providing students with meaningful (and `doable') open-ended tasks; assessing student performance; and rescoping expectations of future instructors and how the freshman year meshes with sophomore activities

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

Internships Predict Women's Salaries but not Men's Salaries for Graduates in Computer Science and Engineering

While the existence of the gender wage gap is well-documented, including in science, technology, engineering and math (STEM), the labor market pathways that correspond to the gap being wide versus narrow in workforce jobs are less well understood. Using data from an NSF-funded longitudinal survey of graduates of engineering and computer science programs from 27 institutions (Nsample=559), we find, controlling for human capital characteristics, that women’s salaries in their first workforce jobs are -7% versus men’s. However, after women and men take one labor market pathway—a tryout—the gender wage gap is non-existent in the offers they accept (women’s salaries are +0.6% versus men’s). For scholars this study illustrates how tryouts may be both an artifact of gender inequality and a way to challenge it