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6. Fleetwide data-enabled reliability improvement of wind turbines

Author

Verstraeten, Timothy, Nowe, Ann, Keller, Jonathan, Guo, Yi, Sheng, Shuangwen, and Helsen, Jan

Subjects
Computer Science - Systems and Control
Abstract

Wind farms are an indispensable driver toward renewable and nonpolluting energy resources. However, as ideal sites are limited, placement in remote and challenging locations results in higher logistics costs and lower average wind speeds. Therefore, it is critical to increase the reliability of the turbines to reduce maintenance costs. Robust implementation requires a thorough understanding of the loads subject to the turbine's control. Yet, such dynamically changing multidimensional loads are uncommon with other machinery, and generally underresearched. Therefore, a multitiered approach is proposed to investigate the load spectrum occurring in wind farms. Our approach relies on both fundamental research using controllable test rigs, as well as analyses of real-world loading conditions in high-frequency supervisory control and data acquisition data. A method is introduced to detect operational zones in wind farm data and link them with load distributions. Additionally, while focused research further investigates the load spectrum, a method is proposed that continuously optimizes the farm's control protocols without the need to fully understand the loads that occur. A case of gearbox failure is investigated based on a vast body of past experiments and suspect loads are identified. Starting from this evidence on the cause and effects of dynamic loads, the potential of our methods is shown by analyzing real-world farm loading conditions on a steady-state case of wake and developing a preventive row-based control protocol for a case of cascading emergency brakes induced by a storm., Comment: 24 pages, 8 figures

Published
2019
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15. Wind turbine main bearing rating lives as determined by IEC 61400-1 and ISO 281: A critical review and exploratory case study

Author

Kenworthy, Jarred, Hart, Edward, Stirling, James, Stock, Adam, Keller, Jonathan, Guo, Yi, Brasseur, James, Evans, Rhys, Kenworthy, Jarred, Hart, Edward, Stirling, James, Stock, Adam, Keller, Jonathan, Guo, Yi, Brasseur, James, and Evans, Rhys

Abstract

This paper studies the rating lives of wind turbine main bearings, as determined by the IEC 61400-1 and ISO 281 standards. A critical review of relevant bearing life theory and turbine design requirements is provided, including discussion on possible shortcomings such as the existence (or not) of the bearing fatigue load limit and the validity of assuming linear damage accumulation. A detailed exploratory case study is then undertaken to determine rating lives for two models of main bearing in a 1.5 MW wind turbine. Rating life assessment is carried out under different conditions, including various combinations of main bearing temperature, wind field characteristics, lubricant viscosity, and contamination levels. Rating lives are found to be sufficiently above the desired 20-year design life for both bearing models under expected operating conditions. For the larger bearing, operational loads are shown to be below or close to the bearing fatigue load limit a vast majority of the time. Key sensitivities for rating life values are temperature and contamination. Overall, the results of this study suggest that an ISO 281 rating life assessment does not account for reported rates of main bearing failures in 1 to 3 MW wind turbines. It is recommended that a similar analysis be undertaken for ISO/TS 16281 rating lives, along with further efforts to identify principal root causes of main bearing failures in future work, possibly leading to a new application standard specific to this component. It is also recommended that the impacts of partial wake impingement on main bearing rating lives are investigated.

Published
2024

17. Teaching Residents

Author

Keller, Jonathan M., Çoruh, Başak, Rounds, Sharon I.S., Series Editor, Dixon, Anne, Series Editor, Schnapp, Lynn M., Series Editor, Kritek, Patricia A., editor, and Richards, Jeremy B., editor

Published
2019
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26. ID2 and HIF-1[alpha] collaborate to protect quiescent hematopoietic stem cells from activation, differentiation, and exhaustion

Author

Jakubison, Brad L., Sarkar, Tanmoy, Gudmundsson, Kristbjorn O., Singh, Shweta, Sun, Lei, Morris, Holly M., Klarmann, Kimberly D., and Keller, Jonathan R.

Subjects
Hematopoietic stem cells -- Genetic aspects -- Physiological aspects -- Health aspects, Transcription factors -- Physiological aspects -- Health aspects, Health care industry
Abstract

Defining mechanism(s) that maintain tissue stem quiescence is important for improving tissue regeneration, cell therapies, aging, and cancer. We report here that genetic ablation of Id2 in adult hematopoietic stem cells (HSCs) promotes increased HSC activation and differentiation, which results in HSC exhaustion and bone marrow failure over time. [Id2.sup.[DELTA]/[DELTA]] HSCs showed increased cycling, ROS production, mitochondrial activation, ATP production, and DNA damage compared with [Id2.sup.+/+] HSCs, supporting the conclusion that [Id2.sup.[DELTA]/[DELTA]] HSCs are less quiescent. Mechanistically, HIF- 1[alpha] expression was decreased in [Id2.sup.[DELTA]/[DELTA]] HSCs, and stabilization of HIF-1[alpha] in [Id2.sup.[DELTA]/[DELTA]] HSCs restored HSC quiescence and rescued HSC exhaustion. Inhibitor of DNA binding 2 (ID2) promoted HIF-1[alpha] expression by binding to the von Hippel-Lindau (VHL) protein and interfering with proteasomal degradation of HIF-1[alpha]. HIF-1[alpha] promoted Id2 expression and enforced a positive feedback loop between ID2 and HIF-1[alpha] to maintain HSC quiescence. Thus, sustained ID2 expression could protect HSCs during stress and improve HSC expansion for gene editing and cell therapies., Introduction Adult hematopoiesis is sustained by a limited number of hematopoietic stem cells (HSCs) that proliferate to self-renew or differentiate to give rise to multipotent progenitor cells (MPPs), which maintain [...]

Published
2022
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35. Early Intervention Programs. Opening the Door to Higher Education. ASHE-ERIC Higher Education Report Vol. 25, No. 6.

Author

ERIC Clearinghouse on Higher Education, Washington, DC., George Washington Univ., Washington, DC. Graduate School of Education and Human Development., Association for the Study of Higher Education., Fenske, Robert H., Geranios, Christine A., Keller, Jonathan E., and Moore, David E.

Abstract

This report addresses issues related to the increasing growth of early intervention programs to encourage high school graduation and college attendance among students from low-income and minority groups. It first presents a brief review of the societal goals of equality for the nation's education system. It then defines the programs "early intervention" and "academic outreach" and synthesizes the demographic and educational problems and challenges related to development of such programs. It continues by describing several notable examples of private initiatives, such as the "I Have a Dream Program." Next, an overview of the burgeoning field of school-college collaborative efforts for early intervention and academic outreach is provided, followed by a survey of federal and state efforts. College and university academic outreach programs are examined from several perspectives, and include an overview of community colleges' involvement in school-college collaboration. The report concludes with evaluations of some early intervention programs and recommendations for follow-up by college and university administrators. An appendix provides brief descriptions of 27 institutional outreach programs. (Contains approximately 130 references.) (DB)

Published
1997

36. Early Intervention Programs: Opening the Door to Higher Education. ERIC Digest.

Author

ERIC Clearinghouse on Higher Education, Washington, DC., George Washington Univ., Washington, DC. Graduate School of Education and Human Development., Fenske, Robert H., Geranios, Christine A., Keller, Jonathan E., and Moore, David E.

Abstract

This digest summarizes a larger document of the same title which examines early intervention programs providing services and resources to encourage low-income/minority youth to finish high school and enter college. It notes provisions of federal law which encourage such programs and the unifying mission of the National Early Intervention Scholarship and Partnership Program. Such programs are seen as either broad early intervention programs, "academic outreach" programs operated by academic institutions and designed to encourage at-risk students to plan for college, or school-college collaboration programs. Programs are differentiated into six types: (1) programs established by philanthropic agencies, (2) federally supported programs, (3) state-sponsored programs with matching federal support, (4) entirely state-supported programs, (5) systemic changes involving school-college collaboration, and (6) college- or university-sponsored programs. Implications of the growth of these programs for college and university administrators are considered and include recommendations to coordinate institutional outreach programs with early intervention programs and document efforts to increase access to their institutions. (DB)

Published
1997

47. Grand challenges in the design, manufacture, and operation of future wind turbine systems

Author

Veers, Paul, primary, Bottasso, Carlo L., additional, Manuel, Lance, additional, Naughton, Jonathan, additional, Pao, Lucy, additional, Paquette, Joshua, additional, Robertson, Amy, additional, Robinson, Michael, additional, Ananthan, Shreyas, additional, Barlas, Thanasis, additional, Bianchini, Alessandro, additional, Bredmose, Henrik, additional, Horcas, Sergio González, additional, Keller, Jonathan, additional, Madsen, Helge Aagaard, additional, Manwell, James, additional, Moriarty, Patrick, additional, Nolet, Stephen, additional, and Rinker, Jennifer, additional

Published
2023
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50. Contractor Collaboration Shines.

Author

Adolphus, Emell and Keller, Jonathan

Subjects
*CONTRACTORS
Abstract

The ENR's Top 600 Specialty Contractors have experienced a third consecutive year of double-digit revenue growth, despite challenges such as labor shortages and rising construction costs. Firms emphasize the importance of investing in employees and adapting to new technologies to improve efficiency. The industry is shifting post-COVID-19, with a focus on skill development, recruitment, and retention strategies to address evolving market demands. Top 600 firms are also managing increasing costs, breaking down bottlenecks, improving supply chain flow, and cultivating recruitment and retention through various strategies. [Extracted from the article]

Published
2024

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