Corrosion fatigue of high strength fastener materials in seawater

Environmental effects which significantly reduce the fatigue life of metals are discussed. Corrosion fatigue is a major concern in the engineering application of high strength fasteners in marine environments. The corrosion fatigue failure of an AISI 41L4O high strength steel blade to hub attachment bolt at the MOD-OA 200 kW wind turbine generator was investigated. The reduction of fatigue strength of AISI 41L4O in marine environments and to obtain similar corrosion fatigue data for candidate replacement materials was studied. The AISI 4140, PH 13-8Mo stainless steel, alloy 718 and alloy MP-35N were tested in axial fatigue at a frequency of 20 Hz in dry air and natural seawater. The fatigue data are fitted by regression equations to allow determination of fatigue strength for a given number of cycles to failure

Mediating Socio-Political Barriers to Water Quality Improvement in Surface Water on Grazed Wildlands

Acute and growing social and legal conflict over regulation of non-point source pollution in Washington State has hampered proactive efforts to improve water quality in streams dominated by grazed watersheds. Livestock farmers caught in the conflict over water quality experience legal risk, reduced quality of life, and financial risk. Nonpoint source pollution is “pollution that is not released through pipes but rather originates from multiple sources over a relatively large area”. This diffuse pollution is notoriously difficult to regulate. Because causality is often not definable, coercing behavior is problematic, and most efforts to address nonpoint source (NPS) pollution rely on promoting voluntary practices. Washington State University Extension, in partnership with the National Riparian Service Team and conservation districts, developed a water quality risk assessment outreach program to focus livestock managers and regulators on the drivers of riparian function and water quality, riparian and upland health rather than sporadically collected water quality monitoring data (Hall et al., 2014). The goal of this long-term outreach has been to influence both regulatory philosophy and farmer behavior. Cooperative Extension has operated as a classic boundary spanner organization (Guston, et al., 2001), (Carr and Wilkinson, 2005), facilitating social interaction in the policy/science/social conflict of water quality in grazing areas. The boundary-spanning role is likely even more critical toward behavior change outcomes in natural resource conflict than the land grant university‟s role as source and interpreter of scientific information. Boundary spanner organizations and individuals “exist at the frontier of the two relatively different social worlds of politics and science”, interacting with principal actors from both sides of the boundary, in order to create a “site of . . . coproduction, the simultaneous production of knowledge and social order” (Guston, 2001, p. 401). They have three defining characteristics: “1) they help negotiate the boundary between science and decision-making, 2) they exist between two distinct social worlds with definite responsibility and accountability to both sides of the boundary, and 3) they provide a space to legitimize the use of boundary objects” (Cash, 2001, p. 439). Boundary-spanning individuals are called to exercise cultural awareness in order to see past surface words and gestures to the underlying beliefs and values which are the true seat of behavior; they then exercise diplomacy to bridge this cultural chasm toward a mutually beneficial end

Ideal and Actual Mentor Teacher Characteristics As Perceived by Second-year and Non-returning First-year Public School North Carolina Teachers

The researcher examined non-returning first-year teachers and second year teachers who taught during the 1994-95 school year. The research design included five research questions with six null hypotheses testing for differences among second year teachers\u27 perceptions and non-returning teachers\u27 perceptions of their mentor teachers. After calculating ratings on desired and demonstrated scales by 464 subjects, criteria were ranked on mentor characteristics on 12 tasks. The extent to which each task was demonstrated during their first year\u27s teaching experience was also calculated. Participants indicated that the ideal mentor would advocate for the novice and would demonstrate a sensitive approach in assisting. However, study participants responded that the more essential characteristics were not present in their experience with mentors. When examining differences between returning and non-returning teachers\u27 perceptions of mentor characteristics, non-returning teachers expressed a stronger desire to have their mentor be understanding, empathetic, and communicative and to teach in a similar curricular area. Further, they would have liked to have had more discussion regarding their teaching practice and a convenient time to meet and share information. When exploring the differences on desired and demonstrated scales in the perception of their actual experiences, significant differences were found in all 12 tasks. Additional analyses revealed significant differences in male and female perceptions but no differences were found when considering grade level teaching assignment

Response maxima in time-modulated turbulence: Direct Numerical Simulations

The response of turbulent flow to time-modulated forcing is studied by direct numerical simulations of the Navier-Stokes equations. The large-scale forcing is modulated via periodic energy input variations at frequency $\omega$. The response is maximal for frequencies in the range of the inverse of the large eddy turnover time, confirming the mean-field predictions of von der Heydt, Grossmann and Lohse (Phys. Rev. E 67, 046308 (2003)). In accordance with the theory the response maximum shows only a small dependence on the Reynolds number and is also quite insensitive to the particular flow-quantity that is monitored, e.g., kinetic energy, dissipation-rate, or Taylor-Reynolds number. At sufficiently high frequencies the amplitude of the kinetic energy response decreases as $1/\omega$. For frequencies beyond the range of maximal response, a significant change in phase-shift relative to the time-modulated forcing is observed.Comment: submitted to Europhysics Letters (EPL), 8 pages, 8 Postscript figures, uses epl.cl

High Sensitivity Search for v_e’s from the Sun and Other Sources at KamLAND

Data corresponding to a KamLAND detector exposure of 0.28 kton yr has been used to search for ν̅ _e’s in the energy range 8.3 < E_(ν̅e) < 14.8  MeV. No candidates were found for an expected background of 1.1±0.4 events. This result can be used to obtain a limit on ν̅_e fluxes of any origin. Assuming that all ν̅_e flux has its origin in the Sun and has the characteristic ^8B solar ν_e energy spectrum, we obtain an upper limit of 3.7×10^2  cm^(-2) ^(s-1) (90% C.L.) on the ν̅_e flux. We interpret this limit, corresponding to 2.8×10^(-4) of the standard solar model ^8B ν_e flux, in the framework of spin-flavor precession and neutrino decay models

Animal Feeding Operations and Water Quality--Resources and Livestock in Balance

This article describes an education program that was developed to provide conservation district staff an understanding of state and federal water quality rules and guidance on when to recommend specific best management practices to livestock producers to protect water quality. Real farm case studies were used to teach site-specific conditions that would place a livestock owner at risk of having a significant negative impact on surface or ground water quality. Specific outcomes were case studies in PowerPoint presentations, best management fact sheets, and a livestock-influenced water quality risk assessment tool