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Sample records for adult dislocated workers

  1. 20 CFR 663.105 - When must adults and dislocated workers be registered?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 20 Employees' Benefits 3 2011-04-01 2011-04-01 false When must adults and dislocated workers be... LABOR ADULT AND DISLOCATED WORKER ACTIVITIES UNDER TITLE I OF THE WORKFORCE INVESTMENT ACT Delivery of Adult and Dislocated Worker Services Through the One-Stop Delivery System § 663.105 When must adults...

  2. 20 CFR 663.105 - When must adults and dislocated workers be registered?

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 20 Employees' Benefits 4 2013-04-01 2013-04-01 false When must adults and dislocated workers be... LABOR (CONTINUED) ADULT AND DISLOCATED WORKER ACTIVITIES UNDER TITLE I OF THE WORKFORCE INVESTMENT ACT Delivery of Adult and Dislocated Worker Services Through the One-Stop Delivery System § 663.105 When...

  3. 20 CFR 663.105 - When must adults and dislocated workers be registered?

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 20 Employees' Benefits 4 2012-04-01 2012-04-01 false When must adults and dislocated workers be... LABOR (CONTINUED) ADULT AND DISLOCATED WORKER ACTIVITIES UNDER TITLE I OF THE WORKFORCE INVESTMENT ACT Delivery of Adult and Dislocated Worker Services Through the One-Stop Delivery System § 663.105 When...

  4. 20 CFR 663.105 - When must adults and dislocated workers be registered?

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 20 Employees' Benefits 4 2014-04-01 2014-04-01 false When must adults and dislocated workers be... LABOR (CONTINUED) ADULT AND DISLOCATED WORKER ACTIVITIES UNDER TITLE I OF THE WORKFORCE INVESTMENT ACT Delivery of Adult and Dislocated Worker Services Through the One-Stop Delivery System § 663.105 When...

  5. 20 CFR 663.105 - When must adults and dislocated workers be registered?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 20 Employees' Benefits 3 2010-04-01 2010-04-01 false When must adults and dislocated workers be registered? 663.105 Section 663.105 Employees' Benefits EMPLOYMENT AND TRAINING ADMINISTRATION, DEPARTMENT OF LABOR ADULT AND DISLOCATED WORKER ACTIVITIES UNDER TITLE I OF THE WORKFORCE INVESTMENT ACT Delivery of Adult and Dislocated Worker...

  6. 20 CFR 663.115 - What are the eligibility criteria for core services for dislocated workers in the adult and...

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... services for dislocated workers in the adult and dislocated worker programs? 663.115 Section 663.115 Employees' Benefits EMPLOYMENT AND TRAINING ADMINISTRATION, DEPARTMENT OF LABOR ADULT AND DISLOCATED WORKER ACTIVITIES UNDER TITLE I OF THE WORKFORCE INVESTMENT ACT Delivery of Adult and Dislocated Worker...

  7. 20 CFR 663.300 - What are training services for adults and dislocated workers?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 20 Employees' Benefits 3 2011-04-01 2011-04-01 false What are training services for adults and..., DEPARTMENT OF LABOR ADULT AND DISLOCATED WORKER ACTIVITIES UNDER TITLE I OF THE WORKFORCE INVESTMENT ACT Training Services § 663.300 What are training services for adults and dislocated workers? Training...

  8. 20 CFR 663.200 - What are intensive services for adults and dislocated workers?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 20 Employees' Benefits 3 2011-04-01 2011-04-01 false What are intensive services for adults and..., DEPARTMENT OF LABOR ADULT AND DISLOCATED WORKER ACTIVITIES UNDER TITLE I OF THE WORKFORCE INVESTMENT ACT Intensive Services § 663.200 What are intensive services for adults and dislocated workers? (a)...

  9. 20 CFR 663.800 - What are supportive services for adults and dislocated workers?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 20 Employees' Benefits 3 2011-04-01 2011-04-01 false What are supportive services for adults and..., DEPARTMENT OF LABOR ADULT AND DISLOCATED WORKER ACTIVITIES UNDER TITLE I OF THE WORKFORCE INVESTMENT ACT Supportive Services § 663.800 What are supportive services for adults and dislocated workers?...

  10. 20 CFR 663.200 - What are intensive services for adults and dislocated workers?

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 20 Employees' Benefits 4 2014-04-01 2014-04-01 false What are intensive services for adults and..., DEPARTMENT OF LABOR (CONTINUED) ADULT AND DISLOCATED WORKER ACTIVITIES UNDER TITLE I OF THE WORKFORCE INVESTMENT ACT Intensive Services § 663.200 What are intensive services for adults and dislocated workers?...

  11. 20 CFR 663.200 - What are intensive services for adults and dislocated workers?

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 20 Employees' Benefits 4 2012-04-01 2012-04-01 false What are intensive services for adults and..., DEPARTMENT OF LABOR (CONTINUED) ADULT AND DISLOCATED WORKER ACTIVITIES UNDER TITLE I OF THE WORKFORCE INVESTMENT ACT Intensive Services § 663.200 What are intensive services for adults and dislocated workers?...

  12. 20 CFR 663.200 - What are intensive services for adults and dislocated workers?

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 20 Employees' Benefits 4 2013-04-01 2013-04-01 false What are intensive services for adults and..., DEPARTMENT OF LABOR (CONTINUED) ADULT AND DISLOCATED WORKER ACTIVITIES UNDER TITLE I OF THE WORKFORCE INVESTMENT ACT Intensive Services § 663.200 What are intensive services for adults and dislocated workers?...

  13. The Experiences of Older Adult Dislocated Workers in Community College Non-Credit Workforce Training Programs

    ERIC Educational Resources Information Center

    Williams, Stelfanie Sherrell

    2011-01-01

    The purpose of this qualitative study was to explore the experiences of older adult dislocated workers who participated in community college non-credit workforce training programs. The research questions guiding the study were: (a) what are the experiences of older adult dislocated workers who attend community college non-credit workforce…

  14. 20 CFR 663.200 - What are intensive services for adults and dislocated workers?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 20 Employees' Benefits 3 2010-04-01 2010-04-01 false What are intensive services for adults and dislocated workers? 663.200 Section 663.200 Employees' Benefits EMPLOYMENT AND TRAINING ADMINISTRATION, DEPARTMENT OF LABOR ADULT AND DISLOCATED WORKER ACTIVITIES UNDER TITLE I OF THE WORKFORCE INVESTMENT ACT Intensive Services § 663.200 What...

  15. 20 CFR 663.800 - What are supportive services for adults and dislocated workers?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 20 Employees' Benefits 3 2010-04-01 2010-04-01 false What are supportive services for adults and dislocated workers? 663.800 Section 663.800 Employees' Benefits EMPLOYMENT AND TRAINING ADMINISTRATION, DEPARTMENT OF LABOR ADULT AND DISLOCATED WORKER ACTIVITIES UNDER TITLE I OF THE WORKFORCE INVESTMENT ACT Supportive Services § 663.800 What...

  16. 20 CFR 663.300 - What are training services for adults and dislocated workers?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 20 Employees' Benefits 3 2010-04-01 2010-04-01 false What are training services for adults and dislocated workers? 663.300 Section 663.300 Employees' Benefits EMPLOYMENT AND TRAINING ADMINISTRATION, DEPARTMENT OF LABOR ADULT AND DISLOCATED WORKER ACTIVITIES UNDER TITLE I OF THE WORKFORCE INVESTMENT ACT Training Services § 663.300 What...

  17. 20 CFR 663.800 - What are supportive services for adults and dislocated workers?

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 20 Employees' Benefits 4 2013-04-01 2013-04-01 false What are supportive services for adults and..., DEPARTMENT OF LABOR (CONTINUED) ADULT AND DISLOCATED WORKER ACTIVITIES UNDER TITLE I OF THE WORKFORCE INVESTMENT ACT Supportive Services § 663.800 What are supportive services for adults and dislocated...

  18. 20 CFR 663.300 - What are training services for adults and dislocated workers?

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 20 Employees' Benefits 4 2012-04-01 2012-04-01 false What are training services for adults and..., DEPARTMENT OF LABOR (CONTINUED) ADULT AND DISLOCATED WORKER ACTIVITIES UNDER TITLE I OF THE WORKFORCE INVESTMENT ACT Training Services § 663.300 What are training services for adults and dislocated...

  19. 20 CFR 663.300 - What are training services for adults and dislocated workers?

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 20 Employees' Benefits 4 2014-04-01 2014-04-01 false What are training services for adults and..., DEPARTMENT OF LABOR (CONTINUED) ADULT AND DISLOCATED WORKER ACTIVITIES UNDER TITLE I OF THE WORKFORCE INVESTMENT ACT Training Services § 663.300 What are training services for adults and dislocated...

  20. 20 CFR 663.800 - What are supportive services for adults and dislocated workers?

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 20 Employees' Benefits 4 2012-04-01 2012-04-01 false What are supportive services for adults and..., DEPARTMENT OF LABOR (CONTINUED) ADULT AND DISLOCATED WORKER ACTIVITIES UNDER TITLE I OF THE WORKFORCE INVESTMENT ACT Supportive Services § 663.800 What are supportive services for adults and dislocated...

  1. 20 CFR 663.300 - What are training services for adults and dislocated workers?

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 20 Employees' Benefits 4 2013-04-01 2013-04-01 false What are training services for adults and..., DEPARTMENT OF LABOR (CONTINUED) ADULT AND DISLOCATED WORKER ACTIVITIES UNDER TITLE I OF THE WORKFORCE INVESTMENT ACT Training Services § 663.300 What are training services for adults and dislocated...

  2. 20 CFR 663.800 - What are supportive services for adults and dislocated workers?

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 20 Employees' Benefits 4 2014-04-01 2014-04-01 false What are supportive services for adults and..., DEPARTMENT OF LABOR (CONTINUED) ADULT AND DISLOCATED WORKER ACTIVITIES UNDER TITLE I OF THE WORKFORCE INVESTMENT ACT Supportive Services § 663.800 What are supportive services for adults and dislocated...

  3. 20 CFR 663.115 - What are the eligibility criteria for core services for dislocated workers in the adult and...

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... services for dislocated workers in the adult and dislocated worker programs? 663.115 Section 663.115 Employees' Benefits EMPLOYMENT AND TRAINING ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) ADULT AND DISLOCATED WORKER ACTIVITIES UNDER TITLE I OF THE WORKFORCE INVESTMENT ACT Delivery of Adult and...

  4. 20 CFR 663.115 - What are the eligibility criteria for core services for dislocated workers in the adult and...

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... services for dislocated workers in the adult and dislocated worker programs? 663.115 Section 663.115 Employees' Benefits EMPLOYMENT AND TRAINING ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) ADULT AND DISLOCATED WORKER ACTIVITIES UNDER TITLE I OF THE WORKFORCE INVESTMENT ACT Delivery of Adult and...

  5. 20 CFR 663.115 - What are the eligibility criteria for core services for dislocated workers in the adult and...

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... services for dislocated workers in the adult and dislocated worker programs? 663.115 Section 663.115 Employees' Benefits EMPLOYMENT AND TRAINING ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) ADULT AND DISLOCATED WORKER ACTIVITIES UNDER TITLE I OF THE WORKFORCE INVESTMENT ACT Delivery of Adult and...

  6. 20 CFR 663.115 - What are the eligibility criteria for core services for dislocated workers in the adult and...

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 20 Employees' Benefits 3 2010-04-01 2010-04-01 false What are the eligibility criteria for core services for dislocated workers in the adult and dislocated worker programs? 663.115 Section 663.115 Employees' Benefits EMPLOYMENT AND TRAINING ADMINISTRATION, DEPARTMENT OF LABOR ADULT AND DISLOCATED WORKER ACTIVITIES UNDER TITLE I OF THE...

  7. 20 CFR 663.110 - What are the eligibility criteria for core services for adults in the adult and dislocated worker...

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... services for adults in the adult and dislocated worker programs? 663.110 Section 663.110 Employees' Benefits EMPLOYMENT AND TRAINING ADMINISTRATION, DEPARTMENT OF LABOR ADULT AND DISLOCATED WORKER ACTIVITIES UNDER TITLE I OF THE WORKFORCE INVESTMENT ACT Delivery of Adult and Dislocated Worker Services...

  8. 20 CFR 663.610 - Does the statutory priority for use of adult funds also apply to dislocated worker funds?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 20 Employees' Benefits 3 2011-04-01 2011-04-01 false Does the statutory priority for use of adult... TRAINING ADMINISTRATION, DEPARTMENT OF LABOR ADULT AND DISLOCATED WORKER ACTIVITIES UNDER TITLE I OF THE... adult funds also apply to dislocated worker funds? No, the statutory priority applies to adult funds...

  9. 20 CFR 663.110 - What are the eligibility criteria for core services for adults in the adult and dislocated worker...

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... services for adults in the adult and dislocated worker programs? 663.110 Section 663.110 Employees' Benefits EMPLOYMENT AND TRAINING ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) ADULT AND DISLOCATED WORKER ACTIVITIES UNDER TITLE I OF THE WORKFORCE INVESTMENT ACT Delivery of Adult and Dislocated...

  10. 20 CFR 663.110 - What are the eligibility criteria for core services for adults in the adult and dislocated worker...

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... services for adults in the adult and dislocated worker programs? 663.110 Section 663.110 Employees' Benefits EMPLOYMENT AND TRAINING ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) ADULT AND DISLOCATED WORKER ACTIVITIES UNDER TITLE I OF THE WORKFORCE INVESTMENT ACT Delivery of Adult and Dislocated...

  11. 20 CFR 663.110 - What are the eligibility criteria for core services for adults in the adult and dislocated worker...

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... services for adults in the adult and dislocated worker programs? 663.110 Section 663.110 Employees' Benefits EMPLOYMENT AND TRAINING ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) ADULT AND DISLOCATED WORKER ACTIVITIES UNDER TITLE I OF THE WORKFORCE INVESTMENT ACT Delivery of Adult and Dislocated...

  12. 20 CFR 663.610 - Does the statutory priority for use of adult funds also apply to dislocated worker funds?

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 20 Employees' Benefits 4 2014-04-01 2014-04-01 false Does the statutory priority for use of adult... TRAINING ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) ADULT AND DISLOCATED WORKER ACTIVITIES UNDER TITLE... priority for use of adult funds also apply to dislocated worker funds? No, the statutory priority...

  13. 20 CFR 663.145 - What services are WIA title I adult and dislocated workers formula funds used to provide?

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 20 Employees' Benefits 4 2014-04-01 2014-04-01 false What services are WIA title I adult and... TRAINING ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) ADULT AND DISLOCATED WORKER ACTIVITIES UNDER TITLE I OF THE WORKFORCE INVESTMENT ACT Delivery of Adult and Dislocated Worker Services Through the...

  14. 20 CFR 663.610 - Does the statutory priority for use of adult funds also apply to dislocated worker funds?

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 20 Employees' Benefits 4 2013-04-01 2013-04-01 false Does the statutory priority for use of adult... TRAINING ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) ADULT AND DISLOCATED WORKER ACTIVITIES UNDER TITLE... priority for use of adult funds also apply to dislocated worker funds? No, the statutory priority...

  15. 20 CFR 663.145 - What services are WIA title I adult and dislocated workers formula funds used to provide?

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 20 Employees' Benefits 4 2012-04-01 2012-04-01 false What services are WIA title I adult and... TRAINING ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) ADULT AND DISLOCATED WORKER ACTIVITIES UNDER TITLE I OF THE WORKFORCE INVESTMENT ACT Delivery of Adult and Dislocated Worker Services Through the...

  16. 20 CFR 663.145 - What services are WIA title I adult and dislocated workers formula funds used to provide?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 20 Employees' Benefits 3 2011-04-01 2011-04-01 false What services are WIA title I adult and... TRAINING ADMINISTRATION, DEPARTMENT OF LABOR ADULT AND DISLOCATED WORKER ACTIVITIES UNDER TITLE I OF THE WORKFORCE INVESTMENT ACT Delivery of Adult and Dislocated Worker Services Through the One-Stop...

  17. 20 CFR 663.610 - Does the statutory priority for use of adult funds also apply to dislocated worker funds?

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 20 Employees' Benefits 4 2012-04-01 2012-04-01 false Does the statutory priority for use of adult... TRAINING ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) ADULT AND DISLOCATED WORKER ACTIVITIES UNDER TITLE... priority for use of adult funds also apply to dislocated worker funds? No, the statutory priority...

  18. 20 CFR 663.145 - What services are WIA title I adult and dislocated workers formula funds used to provide?

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 20 Employees' Benefits 4 2013-04-01 2013-04-01 false What services are WIA title I adult and... TRAINING ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) ADULT AND DISLOCATED WORKER ACTIVITIES UNDER TITLE I OF THE WORKFORCE INVESTMENT ACT Delivery of Adult and Dislocated Worker Services Through the...

  19. 20 CFR 663.150 - What core services must be provided to adults and dislocated workers?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... core services described in WIA section 134(d)(2) and 20 CFR 662.240 must be provided in each local area... 20 Employees' Benefits 3 2011-04-01 2011-04-01 false What core services must be provided to adults... ADMINISTRATION, DEPARTMENT OF LABOR ADULT AND DISLOCATED WORKER ACTIVITIES UNDER TITLE I OF THE...

  20. 20 CFR 663.150 - What core services must be provided to adults and dislocated workers?

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ..., all of the core services described in WIA section 134(d)(2) and 20 CFR 662.240 must be provided in... 20 Employees' Benefits 4 2013-04-01 2013-04-01 false What core services must be provided to adults... ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) ADULT AND DISLOCATED WORKER ACTIVITIES UNDER TITLE I OF...

  1. 20 CFR 663.150 - What core services must be provided to adults and dislocated workers?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... core services described in WIA section 134(d)(2) and 20 CFR 662.240 must be provided in each local area... 20 Employees' Benefits 3 2010-04-01 2010-04-01 false What core services must be provided to adults... ADMINISTRATION, DEPARTMENT OF LABOR ADULT AND DISLOCATED WORKER ACTIVITIES UNDER TITLE I OF THE...

  2. 20 CFR 663.150 - What core services must be provided to adults and dislocated workers?

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ..., all of the core services described in WIA section 134(d)(2) and 20 CFR 662.240 must be provided in... 20 Employees' Benefits 4 2014-04-01 2014-04-01 false What core services must be provided to adults... ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) ADULT AND DISLOCATED WORKER ACTIVITIES UNDER TITLE I OF...

  3. 20 CFR 663.150 - What core services must be provided to adults and dislocated workers?

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ..., all of the core services described in WIA section 134(d)(2) and 20 CFR 662.240 must be provided in... 20 Employees' Benefits 4 2012-04-01 2012-04-01 false What core services must be provided to adults... ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) ADULT AND DISLOCATED WORKER ACTIVITIES UNDER TITLE I OF...

  4. 20 CFR 663.610 - Does the statutory priority for use of adult funds also apply to dislocated worker funds?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 20 Employees' Benefits 3 2010-04-01 2010-04-01 false Does the statutory priority for use of adult funds also apply to dislocated worker funds? 663.610 Section 663.610 Employees' Benefits EMPLOYMENT AND TRAINING ADMINISTRATION, DEPARTMENT OF LABOR ADULT AND DISLOCATED WORKER ACTIVITIES UNDER TITLE I OF THE WORKFORCE INVESTMENT ACT Priority...

  5. 20 CFR 663.145 - What services are WIA title I adult and dislocated workers formula funds used to provide?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 20 Employees' Benefits 3 2010-04-01 2010-04-01 false What services are WIA title I adult and dislocated workers formula funds used to provide? 663.145 Section 663.145 Employees' Benefits EMPLOYMENT AND TRAINING ADMINISTRATION, DEPARTMENT OF LABOR ADULT AND DISLOCATED WORKER ACTIVITIES UNDER TITLE I OF THE WORKFORCE INVESTMENT ACT Delivery...

  6. 20 CFR 663.110 - What are the eligibility criteria for core services for adults in the adult and dislocated worker...

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 20 Employees' Benefits 3 2010-04-01 2010-04-01 false What are the eligibility criteria for core services for adults in the adult and dislocated worker programs? 663.110 Section 663.110 Employees' Benefits EMPLOYMENT AND TRAINING ADMINISTRATION, DEPARTMENT OF LABOR ADULT AND DISLOCATED WORKER ACTIVITIES UNDER TITLE I OF THE WORKFORCE...

  7. 20 CFR 663.100 - What is the role of the adult and dislocated worker programs in the One-Stop delivery system?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 20 CFR part 662. Consistent with those provisions: (1) Core services for adults and dislocated... 20 Employees' Benefits 3 2011-04-01 2011-04-01 false What is the role of the adult and dislocated... AND TRAINING ADMINISTRATION, DEPARTMENT OF LABOR ADULT AND DISLOCATED WORKER ACTIVITIES UNDER TITLE...

  8. 20 CFR 664.500 - May youth participate in both youth and adult/dislocated worker programs concurrently?

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 20 Employees' Benefits 4 2014-04-01 2014-04-01 false May youth participate in both youth and adult... ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) YOUTH ACTIVITIES UNDER TITLE I OF THE WORKFORCE INVESTMENT ACT Concurrent Enrollment § 664.500 May youth participate in both youth and adult/dislocated worker...

  9. 20 CFR 664.500 - May youth participate in both youth and adult/dislocated worker programs concurrently?

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 20 Employees' Benefits 4 2013-04-01 2013-04-01 false May youth participate in both youth and adult... ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) YOUTH ACTIVITIES UNDER TITLE I OF THE WORKFORCE INVESTMENT ACT Concurrent Enrollment § 664.500 May youth participate in both youth and adult/dislocated worker...

  10. 20 CFR 664.500 - May youth participate in both youth and adult/dislocated worker programs concurrently?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 20 Employees' Benefits 3 2011-04-01 2011-04-01 false May youth participate in both youth and adult... ADMINISTRATION, DEPARTMENT OF LABOR YOUTH ACTIVITIES UNDER TITLE I OF THE WORKFORCE INVESTMENT ACT Concurrent Enrollment § 664.500 May youth participate in both youth and adult/dislocated worker programs...

  11. 20 CFR 664.500 - May youth participate in both youth and adult/dislocated worker programs concurrently?

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 20 Employees' Benefits 4 2012-04-01 2012-04-01 false May youth participate in both youth and adult... ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) YOUTH ACTIVITIES UNDER TITLE I OF THE WORKFORCE INVESTMENT ACT Concurrent Enrollment § 664.500 May youth participate in both youth and adult/dislocated worker...

  12. 20 CFR 663.100 - What is the role of the adult and dislocated worker programs in the One-Stop delivery system?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... services are organized into three levels: core, intensive, and training. (b) The chief elected official or his/her designee(s), as the local grant recipient(s) for the adult and dislocated worker programs, is... AND TRAINING ADMINISTRATION, DEPARTMENT OF LABOR ADULT AND DISLOCATED WORKER ACTIVITIES UNDER TITLE...

  13. Dislocated Worker Project.

    ERIC Educational Resources Information Center

    1988

    Due to the severe economic decline in the automobile manufacturing industry in southeastern Michigan, a Dislocated Workers Program has been developed through the partnership of the Flint Area Chamber of Commerce, three community colleges, the National Center for Research in Vocational Education, the Michigan State Department of Education, the…

  14. 20 CFR 664.500 - May youth participate in both youth and adult/dislocated worker programs concurrently?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 20 Employees' Benefits 3 2010-04-01 2010-04-01 false May youth participate in both youth and adult/dislocated worker programs concurrently? 664.500 Section 664.500 Employees' Benefits EMPLOYMENT AND TRAINING ADMINISTRATION, DEPARTMENT OF LABOR YOUTH ACTIVITIES UNDER TITLE I OF THE WORKFORCE INVESTMENT ACT Concurrent Enrollment § 664.500 May...

  15. 20 CFR 663.100 - What is the role of the adult and dislocated worker programs in the One-Stop delivery system?

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... partners described in 20 CFR part 662. Consistent with those provisions: (1) Core services for adults and... 20 Employees' Benefits 4 2013-04-01 2013-04-01 false What is the role of the adult and dislocated... AND TRAINING ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) ADULT AND DISLOCATED WORKER...

  16. 20 CFR 663.100 - What is the role of the adult and dislocated worker programs in the One-Stop delivery system?

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... services. The services are organized into three levels: core, intensive, and training. (b) The chief elected official or his/her designee(s), as the local grant recipient(s) for the adult and dislocated... AND TRAINING ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) ADULT AND DISLOCATED WORKER...

  17. 20 CFR 663.100 - What is the role of the adult and dislocated worker programs in the One-Stop delivery system?

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... services. The services are organized into three levels: core, intensive, and training. (b) The chief elected official or his/her designee(s), as the local grant recipient(s) for the adult and dislocated... AND TRAINING ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) ADULT AND DISLOCATED WORKER...

  18. 20 CFR 663.120 - Are displaced homemakers eligible for dislocated worker activities under WIA?

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) ADULT AND DISLOCATED WORKER ACTIVITIES UNDER TITLE I OF THE WORKFORCE INVESTMENT ACT Delivery of Adult and Dislocated Worker Services Through the One-Stop Delivery... the adult program....

  19. 20 CFR 663.120 - Are displaced homemakers eligible for dislocated worker activities under WIA?

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) ADULT AND DISLOCATED WORKER ACTIVITIES UNDER TITLE I OF THE WORKFORCE INVESTMENT ACT Delivery of Adult and Dislocated Worker Services Through the One-Stop Delivery... the adult program....

  20. 20 CFR 663.120 - Are displaced homemakers eligible for dislocated worker activities under WIA?

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) ADULT AND DISLOCATED WORKER ACTIVITIES UNDER TITLE I OF THE WORKFORCE INVESTMENT ACT Delivery of Adult and Dislocated Worker Services Through the One-Stop Delivery... the adult program....

  1. Community College Adjustment among Dislocated Workers

    ERIC Educational Resources Information Center

    Schwitzer, Alan M.; Duggan, Molly H.; Laughlin, Janet T.; Walker, Martha A.

    2011-01-01

    Community colleges often are catalysts for economic and workforce development in localities with high unemployment or large numbers of dislocated workers. Increasingly, dislocated workers--individuals who have experienced job loss due to occupational closings, reduced workforces, or severe local economic downturns--are enrolling in educational and…

  2. The Perceptions of Dislocated Workers under the Workforce Investment Act

    ERIC Educational Resources Information Center

    Wilson, Michael S.; Brown, James M.

    2012-01-01

    This descriptive qualitative case study investigated the perceptions of dislocated workers offered program services through the Workforce Investment Act's (WIA) Dislocated Worker program in Minnesota. This research focused on recently dislocated workers who lost their jobs through no fault of their own and hence were eligible for unemployment…

  3. The Dislocated Worker: When Training Is Not Enough.

    ERIC Educational Resources Information Center

    Blong, John T.; Shultz, Rose M.

    1990-01-01

    Discusses the socioeconomic effects of plant closings, focusing on the problems faced by dislocated workers who lack the financial resources to complete a retraining program. Describes the Eastern Iowa Community College District's efforts to train and counsel dislocated workers through its Caterpillar Worker Assistance Center. (DMM)

  4. A Comparison of Starting Wages and Job Satisfaction for Reemployed Dislocated Workers Participating in the Rock County Dislocated Worker Program.

    ERIC Educational Resources Information Center

    Borremans, Robert T.

    Following the economic recession of the early 1980's and the consequent high levels of unemployment in Rock County, a program was created at the Blackhawk Technical Institute (BTI) to assist dislocated workers reentering the labor force. The Rock County Dislocated Worker Program was intended as a comprehensive program with two principal activities…

  5. The New Dislocated Worker. Trends and Issues Alerts.

    ERIC Educational Resources Information Center

    Imel, Susan

    In the past, worker displacement resulting from structural changes in the economy remained confined to industrial occupations such as manufacturing. The recent trends toward corporate restructuring, global competition, and military downsizing have created new groups of dislocated workers, including upper and middle management and military…

  6. Personal and Occupational Mobility Characteristics of Selected Dislocated Newspaper Workers.

    ERIC Educational Resources Information Center

    Benton, Jackie Lamar

    A study of dislocated newspaper workers in Baton Rouge, Louisiana, was conducted to describe their personal and occupational mobility characteristics and the residual effect of their separation and unemployment. The descriptive study focused on demographic characteristics, employment history, occupational mobility, economic and emotional impact,…

  7. Dislocated Workers. Comparison of Assistance Programs. Briefing Report to Congressional Requesters.

    ERIC Educational Resources Information Center

    General Accounting Office, Washington, DC. Div. of Human Resources.

    Information was collected and compared on services provided to dislocated workers by the Trade Adjustment Assistance (TAA) and the Economic Dislocation and Worker Adjustment Assistance (EDWAA) programs. (TAA and EDWAA are the two major federal programs created to help dislocated workers make the transition to new employment.) Findings were based…

  8. 76 FR 43729 - Notice of Random Assignment Study To Evaluate Workforce Investment Act Adult and Dislocated...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-21

    ...The Department of Labor (DOL or the Department) is prepared to conduct an evaluation to provide rigorous, nationally representative estimates of the net impacts of intensive services and training provided under the Workforce Investment Act (WIA) Adult and Dislocated Worker Programs. The Department has determined that it is in the public interest to use a random assignment impact methodology......

  9. Helping the Dislocated Worker: Planning Community Services. Research and Development Series No. 243A.

    ERIC Educational Resources Information Center

    Zahniser, Gale L.; Ashley, William L.

    This guide, one in a series of three publications for vocational program developers and others to use in planning and developing a community-based response to worker dislocation, provides a generic approach to program development. Discussed first are the causes, future, and impact of worker dislocation. The next chapter is devoted to various…

  10. New Economy Work (NEW) Scholarships: Universal Access to Training for Dislocated Workers. Policy Report.

    ERIC Educational Resources Information Center

    Weinstein, Paul, Jr.

    The New Economy Work (NEW) Scholarship is a proposed scholarship designed to reform federal training programs and to make them universally accessible to dislocated or disadvantaged workers. NEW Scholarships would accomplish the following things: (1) make access to training for dislocated workers as universally available as access to college; (2)…

  11. Factors Related to Predicting Grade Point Averages of Dislocated Workers at a Rural Community College

    ERIC Educational Resources Information Center

    Gregory, James Brent

    2010-01-01

    The purpose of the study was to examine relationships which existed between selected demographics and college grade point averages "GPAs" for dislocated workers and non dislocated workers enrolled in career-technical courses at a rural community college. The variables included in the study are age, gender, and marital status. The study also…

  12. Dislocation

    MedlinePlus

    Joint dislocation ... It may be hard to tell a dislocated joint from a broken bone . Both are emergencies. You ... to repair a ligament that tears when the joint is dislocated is needed. Injuries to nerves and ...

  13. Plant Closings. Limited Advance Notice and Assistance Provided Dislocated Workers. Report to Congressional Committees.

    ERIC Educational Resources Information Center

    General Accounting Office, Washington, DC. Div. of Human Resources.

    This is the final report in a series issued to assist Congress in assessing the problems of worker dislocation and employer practices related to advance notice and assistance provided to workers. A national survey of 2,600 business establishments was conducted to determine: (1) the extent of business closures and permanent layoffs between January…

  14. Dislocations

    MedlinePlus

    Dislocations are joint injuries that force the ends of your bones out of position. The cause is often a fall or a blow, sometimes from playing a contact sport. You can dislocate your ankles, knees, shoulders, hips, elbows and jaw. You can also dislocate your finger and toe joints. Dislocated joints often are ...

  15. 20 CFR 631.30 - Designation or creation and functions of a State dislocated worker unit or office, and rapid...

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... provision of early intervention services and other appropriate forms of immediate assistance in response to... State dislocated worker unit or office, and rapid response assistance. 631.30 Section 631.30 Employees... dislocated worker unit or office, and rapid response assistance. (a) Designation or creation of...

  16. 20 CFR 671.140 - What are the allowable activities and what dislocated workers may be served under national...

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 20 Employees' Benefits 3 2010-04-01 2010-04-01 false What are the allowable activities and what dislocated workers may be served under national emergency grants? 671.140 Section 671.140 Employees' Benefits EMPLOYMENT AND TRAINING ADMINISTRATION, DEPARTMENT OF LABOR NATIONAL EMERGENCY GRANTS FOR DISLOCATED WORKERS § 671.140 What are the...

  17. Customer Satisfaction Perceptions of Dislocated Workers Served by WIN Job Centers in the Mississippi Corridor Consortium

    ERIC Educational Resources Information Center

    Washburn, Dava Michelle

    2009-01-01

    The purpose of this study was to determine the perceptions of satisfaction of dislocated workers served by WIN Job Centers in the Mississippi Corridor Consortium. Four WIN Job Centers participated in this study: Northeast Mississippi Community College WIN Job Center in Corinth, Northwest Mississippi Community College WIN Job Center in Oxford,…

  18. Dislocation

    MedlinePlus

    ... likely to happen again. Follow-up with an orthopedic surgeon is recommended after a dislocation. ... SE, Mehta A, Maddow C, Luber SD. Critical orthopedic skills and procedures. Emergency Medicine Clinics of North ...

  19. Vocational Education and the Younger Adult Worker.

    ERIC Educational Resources Information Center

    Mertens, Donna M.; Gardner, John A.

    The Younger Adult Worker (YAW) study examined the long-range impact of participation in vocational education through a national cross-sectional survey of 1,539 persons aged 20 to 24 who were in the civilian labor force. After supplementing study data with data from two other national data bases, researchers drew conclusions pertaining to the…

  20. Dislocations

    MedlinePlus

    ... Attempting to move or jam a dislocated bone back in can damage blood vessels, muscles, ligaments, and nerves. Apply an ice pack. Ice can ease swelling and pain in and around the joint. Use ibuprofen or acetaminophen for pain. Think Prevention! Make sure kids wear the appropriate safety gear ...

  1. Dislocated Workers.

    ERIC Educational Resources Information Center

    NAB Clearinghouse Quarterly, 1984

    1984-01-01

    This document is the first issue of a National Alliance of Business publication designed to present proven solutions, cutting-edge strategies, and comprehensive reference materials and to examine in depth in each issue a critical issue related to public/private employment and training partnerships. This first issue addresses one of the most…

  2. Traumatic inferior hip dislocation: a rare adult case with ipsilateral bifocal hip fracture

    PubMed Central

    El Hajj Moussa, Majd; Tawk, Charbel; Hoyek, Fadi; Lahoud, Jean-Claude

    2016-01-01

    Inferior dislocation is a rare type of hip dislocation, especially in adults. Few cases have been reported; most of them were isolated. This is the case of a traumatic adult hip dislocation after a road traffic accident. Reduction was made under general anaesthesia; a CT-Scan after the reduction showed a bifocal non-displaced hip fracture. In this article, we present a small review of the literature and we discuss the possible mechanism of hip dislocation. We found through our case study that this condition is not exclusive to children and CT-Scan is mandatory after the reduction of hip dislocation to eliminate any associated injury. To our knowledge, a bifocal hip fracture has not previously been documented, in the English language literature. PMID:27141043

  3. A Follow-up Study of the Delivery of Title III Services to Dislocated Workers in Ohio.

    ERIC Educational Resources Information Center

    Hollenbeck, Kevin; Bennici, Frank

    A study collected data about Title III of the Job Training Partnership Act (JTPA) services to clients and factors that affected the outcomes from these services. A random sample of 1,347 individuals who had received services was surveyed via telephone. These individuals were dislocated workers who had terminated from a subgrantee's program during…

  4. An Agenda for the 90's: Strategies and Tactics for Conducting an Effective Dislocated Worker Training Program.

    ERIC Educational Resources Information Center

    Spaid, Robin L.; Parsons, Michael H.

    In August 1983, when the second largest employer in Washington County, Maryland, closed its plant, the local unemployment rate was 13%. The following month, Hagerstown Junior College (HJC) received $50,000 in state funds to initiate a dislocated worker (DLW) program. The program included orientation by a counselor, diagnostic testing, and…

  5. Study of the Implementation of the Economic Dislocation and Worker Adjustment Assistance Act. Research and Evaluation Report Series 91-G.

    ERIC Educational Resources Information Center

    SRI International, Menlo Park, CA.

    The design and operations of the Economic Dislocation and Worker Adjustment Assistance (EDWAA) Act program in its implementation year were examined through case studies conducted in 15 states and 30 substate areas. During 6- to 8-day visits to each state, field researchers conducted discussions with state and substate respondents. States almost…

  6. Notch signalling mediates reproductive constraint in the adult worker honeybee.

    PubMed

    Duncan, Elizabeth J; Hyink, Otto; Dearden, Peter K

    2016-01-01

    The hallmark of eusociality is the reproductive division of labour, in which one female caste reproduces, while reproduction is constrained in the subordinate caste. In adult worker honeybees (Apis mellifera) reproductive constraint is conditional: in the absence of the queen and brood, adult worker honeybees activate their ovaries and lay haploid male eggs. Here, we demonstrate that chemical inhibition of Notch signalling can overcome the repressive effect of queen pheromone and promote ovary activity in adult worker honeybees. We show that Notch signalling acts on the earliest stages of oogenesis and that the removal of the queen corresponds with a loss of Notch protein in the germarium. We conclude that the ancient and pleiotropic Notch signalling pathway has been co-opted into constraining reproduction in worker honeybees and we provide the first molecular mechanism directly linking ovary activity in adult worker bees with the presence of the queen. PMID:27485026

  7. Notch signalling mediates reproductive constraint in the adult worker honeybee

    PubMed Central

    Duncan, Elizabeth J.; Hyink, Otto; Dearden, Peter K.

    2016-01-01

    The hallmark of eusociality is the reproductive division of labour, in which one female caste reproduces, while reproduction is constrained in the subordinate caste. In adult worker honeybees (Apis mellifera) reproductive constraint is conditional: in the absence of the queen and brood, adult worker honeybees activate their ovaries and lay haploid male eggs. Here, we demonstrate that chemical inhibition of Notch signalling can overcome the repressive effect of queen pheromone and promote ovary activity in adult worker honeybees. We show that Notch signalling acts on the earliest stages of oogenesis and that the removal of the queen corresponds with a loss of Notch protein in the germarium. We conclude that the ancient and pleiotropic Notch signalling pathway has been co-opted into constraining reproduction in worker honeybees and we provide the first molecular mechanism directly linking ovary activity in adult worker bees with the presence of the queen. PMID:27485026

  8. Dimensions of Problem Drinking among Young Adult Restaurant Workers

    PubMed Central

    Moore, Roland S.; Cunradi, Carol B.; Duke, Michael R.; Ames, Genevieve M.

    2009-01-01

    Background Nationwide surveys identify food service workers as heavy alcohol users. Objectives This article analyzes dimensions and correlates of problem drinking among young adult food service workers. Methods A telephone survey of national restaurant chain employees yielded 1294 completed surveys. Results Hazardous alcohol consumption patterns were seen in 80% of men and 64% of women. Multivariate analysis showed that different dimensions of problem drinking measured by the AUDIT were associated with workers' demographic characteristics, smoking behavior and job category. Conclusions & Scientific Significance These findings offer evidence of extremely high rates of alcohol misuse among young adult restaurant workers. PMID:20180660

  9. Economic Adjustment and Worker Dislocation in a Competitive Society. Report of the Secretary of Labor's Task Force on Economic Adjustment and Worker Dislocation.

    ERIC Educational Resources Information Center

    Department of Labor, Washington, DC.

    According to the Bureau of Labor Statistics (BLS), between 1981 and 1986 approximately 10.8 million persons lost jobs in a manner suggesting that the job losses would be permanent. Experienced workers with three or more years of tenure made up about 5.1 million of the total number of individuals whom BLS reports have termed "displaced workers."…

  10. Finding the Worker: Adult Education and Workers' Education

    ERIC Educational Resources Information Center

    Rose, Amy D.; Jeris, Laurel H.

    2011-01-01

    This article looks at how administrators and teachers who consider themselves adult educators but who find themselves in a union environment come to think about their role and their context. This article is based on research conducted with administrators and teachers working in a joint union-employer sponsored program. Joint programs were…

  11. Educational and Employment Experiences of the Younger Adult Worker.

    ERIC Educational Resources Information Center

    Mertens, Donna M.; Gardner, John A.

    The Younger Adult Worker (YAW) study examined the systematic long-term relationship between exposure to vocational education and various indices of educational and employment outcomes. A telephone survey of 1539 young adults between the ages of 20 and 34 supplemented information from the l966-78 National Longitudinal Surveys of Labor Market…

  12. Compassion fatigue and the adult protective services social worker.

    PubMed

    Bourassa, Dara Bergel

    2009-04-01

    Compassion fatigue is a relatively new term that describes the symptoms that are experienced by social workers and other helping professionals who work with clients experiencing trauma. This article defines the concept of compassion fatigue and relates compassion fatigue to Adult Protective Services (APS) social workers. It is proposed that APS social workers may be susceptible to the deleterious effects of compassion fatigue due to the nature of their work and environment. Suggestions for avoidance of compassion fatigue are also discussed, including self-care strategies and the need for continuing education regarding this phenomenon. PMID:19308828

  13. Effectiveness of Dysphagia Training for Adult Learning Disabilities Support Workers

    ERIC Educational Resources Information Center

    Tredinnick, Gerlind; Cocks, Naomi

    2014-01-01

    This study investigated the effectiveness of a 1-day dysphagia training package delivered to support workers who work with adults with a learning disability. Thirty-eight support staff took part in this study. Twenty-five support staff received training, and 13 did not receive training and therefore acted as a control group. Three questionnaires…

  14. The Learning Industry. Education for Adult Workers.

    ERIC Educational Resources Information Center

    Eurich, Nell P.

    This study focuses on the connection between education and the world of work and the urgency of the endeavor to educate the work force. Part I considers the resources for adult learning in the United States, with a focus on the major providers outside the traditional education system. Technological resources that can extend educational…

  15. Credential Attainment by Older Workers: The Role of Community Colleges and the Dislocated Worker Program in Successful Employment Outcomes

    ERIC Educational Resources Information Center

    Cummins, Phyllis Ann

    2013-01-01

    Workers are remaining in the labor force at older ages and despite their desire to work, those without jobs face unprecedented durations of unemployment. Many of the unemployed lack current skills for jobs in demand and need to either upgrade their skills or be trained for a new occupation to become reemployed. An aging workforce combined with…

  16. Marketing Strategies Preferred by South Carolina One-Stop Career Center Area Directors to Attract Dislocated Workers under the Workforce Investment Act of 1998: Policy Implications

    ERIC Educational Resources Information Center

    Ratliff, Eugene F.

    2011-01-01

    The purpose of this study was to determine the marketing strategies South Carolina One-Stop Career Centers Area Directors felt provided the best opportunity for dislocated workers to learn about their services. Two theories emerged: the Service Marketing Theory and the Word-of-Mouth Marketing Theory. Of the 36 area directors cited for this study,…

  17. Seat Belt Use Among Adult Workers - 21 States, 2013.

    PubMed

    Boal, Winifred L; Li, Jia; Rodriguez-Acosta, Rosa L

    2016-01-01

    Roadway incidents involving motorized vehicles accounted for 24% of fatal occupational injuries in the United States during 2013 and were the leading cause of fatal injuries among workers.* In 2013, workers' compensation costs for serious, nonfatal injuries among work-related roadway incidents involving motorized land vehicles were estimated at $2.96 billion.(†) Seat belt use is a proven method to reduce injuries to motor vehicle occupants (1). Use of lap/shoulder seat belts reduces the risk for fatal injuries to front seat occupants of cars by 45% and the risk to light truck occupants by 60%.(§) To characterize seat belt use among adult workers by occupational group, CDC analyzed data from the 2013 Behavioral Risk Factor Surveillance System (BRFSS) and found that not always using a seat belt was significantly associated with occupational group after controlling for factors known to influence seat belt use. Occupational groups with the highest prevalences of not always using a seat belt included construction and extraction; farming, fishing, and forestry; and installation, maintenance, and repair. To increase seat belt use among persons currently employed, states can enact and enforce primary seat belt laws, employers can set and enforce safety policies requiring seat belt use by all vehicle occupants, and seat belt safety advocates can target interventions to workers in occupational groups with lower reported seat belt use. PMID:27309488

  18. Social Workers' Attitudes toward Older Adults: A Review of the Literature

    ERIC Educational Resources Information Center

    Wang, Donna; Chonody, Jill

    2013-01-01

    Ageist attitudes toward older adults have been recognized as barriers to recruiting and training competent social workers. This article provides a systematic review of the literature that focused on social workers' and social work students' attitudes toward older adults and working with older adults. The authors sought empirical studies…

  19. Environmental Education through Adult Education. A Manual for Adult Educators, Instructors, Teachers and Social Extension Workers.

    ERIC Educational Resources Information Center

    Rugumayo, Edward B., Comp.; Ibikunle-Johnson, Victor O., Comp.

    The purpose of this manual is to make available to adult educators and field extension workers in Kenya resource material that may be used in formal and nonformal training programs for the environmental education of a wide range of target groups. The document begins with a 26-item glossary, an introduction, a section on the document's use,…

  20. 77 FR 37923 - Comment Request for Information Collection for the Workforce Investment Act (WIA) Adult and...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-06-25

    ... Investment Act (WIA) Adult and Dislocated Worker Programs Gold Standard Evaluation (WIA Evaluation); New... than 6 million people annually at a cost of over $3 billion (U.S. Department of Labor, Fiscal Year 2012...--adults and dislocated workers in this group can receive any WIA service for which they are eligible;...

  1. Examining Self-Protection Measures Guarding Adult Protective Services Social Workers against Compassion Fatigue

    ERIC Educational Resources Information Center

    Bourassa, Dara

    2012-01-01

    Little research has focused on the risk factors, effects, and experiences of compassion fatigue among gerontological social workers. This qualitative study explores the experiences and perspectives of nine Adult Protective Services (APS) social workers in relation to compassion fatigue. Results show that the APS social workers combined personal…

  2. Worker honey bee ovary development: seasonal variation and the influence of larval and adult nutrition.

    PubMed

    Hoover, Shelley E R; Higo, Heather A; Winston, Mark L

    2006-01-01

    We examined the effect of larval and adult nutrition on worker honey bee (Apis mellifera L.) ovary development. Workers were fed high or low-pollen diets as larvae, and high or low-protein diets as adults. Workers fed low-protein diets at both life stages had the lowest levels of ovary development, followed by those fed high-protein diets as larvae and low- quality diets as adults, and then those fed diets poor in protein as larvae but high as adults. Workers fed high-protein diets at both life stages had the highest levels of ovary development. The increases in ovary development due to improved dietary protein in the larval and adult life stages were additive. Adult diet also had an effect on body mass. The results demonstrate that both carry-over of larval reserves and nutrients acquired in the adult life stage are important to ovary development in worker honey bees. Carry-over from larval development, however, appears to be less important to adult fecundity than is adult nutrition. Seasonal trends in worker ovary development and mass were examined throughout the brood rearing season. Worker ovary development was lowest in spring, highest in mid-summer, and intermediate in fall. PMID:16228242

  3. Economic Dislocation and Worker Adjustment Assistance Act. Joint Hearings on S. 538 to Implement the Recommendations of the Secretary of Labor's Task Force on Economic Adjustment and Worker Dislocation, and for Other Purposes, before the Subcommittee on Labor and the Subcommittee on Employment and Productivity of the Committee on Labor and Human Resources. United States Senate, One-Hundredth Congress, First Session (March 10 and 26, 1987).

    ERIC Educational Resources Information Center

    Congress of the U.S., Washington, DC. Senate Committee on Labor and Human Resources.

    This congressional report on Senate Bill 538 contains the testimony that was given at joint hearings to debate the passage of the Economic Dislocation and Worker Adjustment Assistance Act. This act, which is based primarily on the recommendations of U.S. Secretary of Labor Brock's blue ribbon task force: (1) creates displaced worker units at the…

  4. The Long-Term Costs of Job Displacement for Young Adult Workers.

    ERIC Educational Resources Information Center

    Kletzer, Lori G.; Fairlie, Robert W.

    2003-01-01

    National Longitudinal Survey of Youth data indicate that earnings losses were large for the first 3 years after displacement, but for young adults they were short lived. After 5 years, shortfall in earnings was 9% for men and 12.5% for women. For older workers, losses represent actual, immediate earnings losses; for younger workers, loss of…

  5. Low-Skilled Workers and Adult Vocational Skills-Upgrading Strategies in Denmark and South Korea

    ERIC Educational Resources Information Center

    Gvaramadze, Irakli

    2010-01-01

    The main objective of the paper was to address the relevance of adult vocational skills-upgrading strategies for low-skilled workers. The research was based on an identification of core elements such as time, cost and access which define and impact on formulation and implementation of adult vocational skills-upgrading strategies. The literature…

  6. Adult Workforce Education Is Reaching Out to Displaced Workers

    ERIC Educational Resources Information Center

    Claypool, Christine Ryan

    2005-01-01

    It was the year 2002. Ohio was reeling from a decline in the manufacturing sector, which left thousands of northwestern Ohio workers unemployed. When the U.S. economy suffers from a recession, states like Ohio that rely heavily upon employment in manufacturing experience the impact first, according to Neal Eiber of Apollo Career Center Adult…

  7. Rescue of newborn ants by older Cataglyphis cursor adult workers.

    PubMed

    Nowbahari, Elise; Amirault, Céline; Hollis, Karen L

    2016-05-01

    Cataglyphis cursor worker ants are capable of highly sophisticated rescue behaviour in which individuals are able to identify what has trapped a nestmate and to direct their behaviour towards that obstacle. Nonetheless, rescue behaviour is constrained by workers' subcaste: whereas foragers, the oldest workers, are able both to give and to receive the most help, the youngest workers, inactives, neither give nor receive any help whatsoever; nurses give and receive intermediate levels of aid, reflecting their intermediate age. Such differences in rescue behaviour across subcastes suggest that age and experience play a critical role. In this species, as in many others in which a sensitive period for nestmate recognition exists, newly enclosed ants, called callows, are adopted by ants belonging not only to different colonies but also to different species; foreign callows receive nearly the same special care provided to resident newborns. Because callows are younger than inactives, which are incapable of soliciting rescue, we wondered whether entrapped callows would receive such aid. In the present study, we artificially ensnared individual callows from their own colony (homocolonial), from a different colony (heterocolonial), and from a different species (heterospecific), and tested each one with groups of five potential C. cursor rescuers, either all foragers or all nurses. Our results show that all three types of callows are able to elicit rescue behaviour from both foragers and nurses. Nonetheless, nurse rescuers are better able to discriminate between the three types of callow victims than are foragers. PMID:26846232

  8. Examining self-protection measures guarding Adult Protective Services social workers against compassion fatigue.

    PubMed

    Bourassa, Dara

    2012-06-01

    Little research has focused on the risk factors, effects, and experiences of compassion fatigue among gerontological social workers. This qualitative study explores the experiences and perspectives of nine Adult Protective Services (APS) social workers in relation to compassion fatigue. Results show that the APS social workers combined personal characteristics and professional factors to develop boundary-setting mechanisms that protected them from experiencing the deleterious symptoms and effects of compassion fatigue. Implications center around the elements needed to implement boundaries in order to maintain a separation between the work and home environment. Suggestions for future research are provided. PMID:22203624

  9. Measles Outbreak among Previously Immunized Adult Healthcare Workers, China, 2015

    PubMed Central

    Zhang, Zhengyi; Zhao, Yuan; Yang, Lili; Lu, Changhong; Meng, Ying; Guan, Xiaoli; An, Hongjin; Zhang, Meizhong; Guo, Wenqin; Shang, Bo; Yu, Jing

    2016-01-01

    Measles is caused by measles virus belonging to genus Morbillivirus of the family Paramyxoviridae. Vaccination has played a critical role in controlling measles infection worldwide. However, in the recent years, outbreaks of measles infection still occur in many developing countries. Here, we report an outbreak of measles among healthcare workers and among the 60 measles infected patients 50 were healthcare workers including doctors, nurses, staff, and medics. Fifty-one patients (85%) tested positive for IgM antibodies against the measles virus and 50 patients (83.3%) tested positive for measles virus RNA. Surprisingly, 73.3% of the infected individuals had been previously immunized against measles. Since there is no infection division in our hospital, the fever clinics are located in the Emergency Division. In addition, the fever and rash were not recognized as measles symptoms at the beginning of the outbreak. These factors result in delay in isolation and early confirmation of the suspected patients and eventually a measles outbreak in the hospital. Our report highlights the importance of following a two-dose measles vaccine program in people including the healthcare workers. In addition, vigilant attention should be paid to medical staff with clinical fever and rash symptoms to avoid a possible nosocomial transmission of measles infection. PMID:27366157

  10. Unravelling the Lifelong Learning Process for Canadian Workers and Adult Learners Acquiring Higher Skills

    ERIC Educational Resources Information Center

    Taylor, Maurice; Trumpower, David; Pavic, Ivana

    2013-01-01

    This article reports on a mixed methods study that investigated aspects of formal, non-formal and informal learning for workers and adult high school learners seeking literacy and essential skills. Three key themes emerged from the qualitative data: motivations for participation in various forms of learning; seeking out informal learning…

  11. The Challenge of the '80's and Beyond: Career Planning and the Adult Blue Collar Worker.

    ERIC Educational Resources Information Center

    Jaffe, Martin Elliot

    Career counseling is a particularly critical need for blue collar men, displaced workers from the declining industries of manufacturing. This article uses developmental theory based on the model of adult development of Daniel Levinson (1978), "Seasons of a Man's Life," to discuss the difficulty of blue collar men in attaining developmental…

  12. Keeping the Doors of Learning Open for Adult Student-Workers within Higher Education?

    ERIC Educational Resources Information Center

    Walters, Shirley; Abrahams, Mark; Witbooi, Sally

    2015-01-01

    The Freedom Charter of the African National Congress (ANC), the triumphant South African liberation movement, proclaims that "the doors of learning shall be open" for all. Twenty years since coming to power, the doors of the universities are struggling to stay open for adult student-workers. An action research project into implementation…

  13. Interacting with Adults with Congenital Deafblindness: The Experiences of Disability Support Workers

    ERIC Educational Resources Information Center

    Prain, Meredith; McVilly, Keith R.; Ramcharan, Paul

    2012-01-01

    Background: This study aimed to gain greater insight into the perspectives of staff on their interactions with adults with congenital deafblindness in light of the research literature reporting these interactions to be lacking in quality and quantity. Method: Data from interviews with 8 disability support workers were analysed using the approach…

  14. Support Systems for Injured Workers. Tierra de Oportunidad Module 5. LAES: Latino Adult Education Services Project.

    ERIC Educational Resources Information Center

    Kissam, Ed; Dorsey, Holda

    This module, which may be used as the basis for a workshop or as a special topic unit in an adult basic education or English-as-a-Second-Language (ESL) course, focuses on support systems for injured workers. The following items are included: module overview; list of basic, thinking, interpersonal, information utilization, and other skills…

  15. 20 CFR 663.600 - What priority must be given to low-income adults and public assistance recipients served with...

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... adults and public assistance recipients served with adult funds under title I? 663.600 Section 663.600 Employees' Benefits EMPLOYMENT AND TRAINING ADMINISTRATION, DEPARTMENT OF LABOR ADULT AND DISLOCATED WORKER... priority must be given to low-income adults and public assistance recipients served with adult funds...

  16. Social Workers as Research Psychotherapists in an Investigation of Cognitive–Behavioral Therapy among Rural Older Adults

    PubMed Central

    Shah, Avani; Scogin, Forrest; Presnell, Andrew; Morthland, Martin; Kaufman, Allan V.

    2013-01-01

    This is a report on the treatment fidelity of in-home cognitive–behavioral therapy (CBT) delivered by a sample of clinically trained, master's-level social workers to a group of primarily rural, medically frail older adults as part of the Project to Enhance Aged Rural Living (PEARL) clinical trial. The social workers in this study received brief didactic and experiential CBT training. Audiotaped sessions were randomly selected and evaluated by independent reviewers. Results showed that the social workers adequately delivered CBT as measured by the Cognitive Therapy Scale. Older adult participants also evidenced pre- posttreatment improvements, suggesting that the social workers' delivery of CBT facilitated improvement. PMID:25949093

  17. Proximal coracobrachialis tendon rupture, subscapularis tendon rupture, and medial dislocation of the long head of the biceps tendon in an adult after traumatic anterior shoulder dislocation.

    PubMed

    Saltzman, Bryan M; Harris, Joshua D; Forsythe, Brian

    2015-01-01

    Rupture of the coracobrachialis is a rare entity, in isolation or in combination with other muscular or tendinous structures. When described, it is often a result of direct trauma to the anatomic area resulting in rupture of the muscle belly. The authors present a case of a 57-year-old female who suffered a proximal coracobrachialis tendon rupture from its origin at the coracoid process, with concomitant subscapularis tear and medial dislocation of the long head of biceps tendon after first time traumatic anterior shoulder dislocation. Two weeks after injury, magnetic resonance imaging suggested the diagnosis, which was confirmed during combined arthroscopic and open technique. Soft-tissue tenodesis of coracobrachialis to the intact short head of the biceps, tenodesis of the long head of biceps to the intertubercular groove, and double-row anatomic repair of the subscapularis were performed. The patient did well postoperatively, and ultimately at 6 months follow-up, she was without pain, and obtained 160° of active forward elevation, 45° of external rotation, internal rotation to T8, 5/5 subscapularis and biceps strength. Scoring scales had improved from the following preoperative to final follow-up: American Shoulder and Elbow Surgeons, 53.33-98.33; constant, 10-100; visual analogue scale-pain, 4-0. DASH score was 5. PMID:25937715

  18. Proximal coracobrachialis tendon rupture, subscapularis tendon rupture, and medial dislocation of the long head of the biceps tendon in an adult after traumatic anterior shoulder dislocation

    PubMed Central

    Saltzman, Bryan M.; Harris, Joshua D.; Forsythe, Brian

    2015-01-01

    Rupture of the coracobrachialis is a rare entity, in isolation or in combination with other muscular or tendinous structures. When described, it is often a result of direct trauma to the anatomic area resulting in rupture of the muscle belly. The authors present a case of a 57-year-old female who suffered a proximal coracobrachialis tendon rupture from its origin at the coracoid process, with concomitant subscapularis tear and medial dislocation of the long head of biceps tendon after first time traumatic anterior shoulder dislocation. Two weeks after injury, magnetic resonance imaging suggested the diagnosis, which was confirmed during combined arthroscopic and open technique. Soft-tissue tenodesis of coracobrachialis to the intact short head of the biceps, tenodesis of the long head of biceps to the intertubercular groove, and double-row anatomic repair of the subscapularis were performed. The patient did well postoperatively, and ultimately at 6 months follow-up, she was without pain, and obtained 160° of active forward elevation, 45° of external rotation, internal rotation to T8, 5/5 subscapularis and biceps strength. Scoring scales had improved from the following preoperative to final follow-up: American Shoulder and Elbow Surgeons, 53.33-98.33; constant, 10-100; visual analogue scale-pain, 4-0. DASH score was 5. PMID:25937715

  19. Regulation of behavioral maturation by a primer pheromone produced by adult worker honey bees

    PubMed Central

    Leoncini, Isabelle; Le Conte, Yves; Costagliola, Guy; Plettner, Erika; Toth, Amy L.; Wang, Mianwei; Huang, Zachary; Bécard, Jean-Marc; Crauser, Didier; Slessor, Keith N.; Robinson, Gene E.

    2004-01-01

    Previous research showed that the presence of older workers causes a delayed onset of foraging in younger individuals in honey bee colonies, but a specific worker inhibitory factor had not yet been identified. Here, we report on the identification of a substance produced by adult forager honey bees, ethyl oleate, that acts as a chemical inhibitory factor to delay age at onset of foraging. Ethyl oleate is synthesized de novo and is present in highest concentrations in the bee's crop. These results suggest that worker behavioral maturation is modulated via trophallaxis, a form of food exchange that also serves as a prominent communication channel in insect societies. Our findings provide critical validation for a model of self-organization explaining how bees are able to respond to fragmentary information with actions that are appropriate to the state of the whole colony. PMID:15572455

  20. Childhood Abuse, Household Dysfunction, and Indicators of Impaired Adult Worker Performance

    PubMed Central

    Anda, Robert F; Fleisher, Vladimir I; Felitti, Vincent J; Edwards, Valerie J; Whitfield, Charles L; Dube, Shanta R; Williamson, David F

    2004-01-01

    Objective: We examined the relation between eight types of adverse childhood experience (ACE) and three indicators of impaired worker performance (serious job problems, financial problems, and absenteeism). Methods: We analyzed data collected for the Adverse Childhood Experiences Study from 9633 currently employed adult members of the Kaiser Foundation Health Plan in San Diego. Results: Strong graded relations were found between the ACE Score (total number of ACE categories experienced) and each measure of impaired worker performance (p < .001). We found strong evidence that the relation between ACE Score and worker performance was mediated by interpersonal relationship problems, emotional distress, somatic symptoms, and substance abuse. Conclusions: The long-term effects of adverse childhood experiences on the workforce impose major human and economic costs that are preventable. These costs merit attention from the business community in conjunction with specialists in occupational medicine and public health. PMID:26704603

  1. Zinc protoporphyrin IX concentrations between normal adults and the lead-exposed workers measured by HPLC, spectrofluorometer, and hematofluorometer.

    PubMed

    Roh, Y M; Kim, K; Kim, H

    2000-10-01

    To establish the relationship between Zinc protoporphyrin (ZPP) concentrations and blood lead (PbB) levels and to identify reliable analytical methods of ZPP and Protoporhyrin (PP), blood samples were obtained from 263 office workers without the history of occupational lead exposure and 49 lead-acid battery workers. The mean concentrations of PbB for the normal adults and the battery workers were 9.26 microg/dl and 42.60 microg/dl, respectively. The geometric mean concentrations of ZPP and PP by HPLC were 18.73 microg/dl and 2.27 microg/dl for normal adults and were 46.99 microg/dl and 5.53 microg/dl for the exposed workers, respectively. The geometric mean concentrations of ZPP and PP by a spectrofluorometer (SF) were 30.27 microg/dl and 5.16 microg/dl for normal adults and were 50.91 microg/dl and 6.69 +/- 1.39 microg/dl for the exposed workers. The geometric mean ZPP concentration measured by a hematofluorometer (HF) was 30.88 microg/dl for normal adults. The results showed that ZPP concentrations measured by HF were consistently higher than those by HPLC and SF for normal adults, and lower for the exposed workers. ZPP concentrations were not correlated with PbB levels for normal adults but a statistically significant correlation was found among the exposed workers. PMID:11061480

  2. 20 CFR 663.820 - What are the eligibility requirements for adults to receive needs-related payments?

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... adults to receive needs-related payments? 663.820 Section 663.820 Employees' Benefits EMPLOYMENT AND TRAINING ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) ADULT AND DISLOCATED WORKER ACTIVITIES UNDER TITLE... requirements for adults to receive needs-related payments? Adults must: (a) Be unemployed, (b) Not qualify...

  3. 20 CFR 663.820 - What are the eligibility requirements for adults to receive needs-related payments?

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... adults to receive needs-related payments? 663.820 Section 663.820 Employees' Benefits EMPLOYMENT AND TRAINING ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) ADULT AND DISLOCATED WORKER ACTIVITIES UNDER TITLE... requirements for adults to receive needs-related payments? Adults must: (a) Be unemployed, (b) Not qualify...

  4. 20 CFR 663.820 - What are the eligibility requirements for adults to receive needs-related payments?

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... adults to receive needs-related payments? 663.820 Section 663.820 Employees' Benefits EMPLOYMENT AND TRAINING ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) ADULT AND DISLOCATED WORKER ACTIVITIES UNDER TITLE... requirements for adults to receive needs-related payments? Adults must: (a) Be unemployed, (b) Not qualify...

  5. The Prevalence of Childhood Adversity among Healthcare Workers and Its Relationship to Adult Life Events, Distress and Impairment

    ERIC Educational Resources Information Center

    Maunder, Robert G.; Peladeau, Nathalie; Savage, Diane; Lancee, William J.

    2010-01-01

    Objective: We investigated the prevalence of childhood adversity among healthcare workers and if such experiences affect responses to adult life stress. Methods: A secondary analysis was conducted of a 2003 study of 176 hospital-based healthcare workers, which surveyed lifetime traumatic events, recent life events, psychological distress, coping,…

  6. Subtalar dislocation

    SciTech Connect

    El-Khoury, G.Y.; Yousefzadeh, D.K.; Mulligan, G.M.; Moore, T.E.

    1982-05-01

    Over a period of three years we have seen nine patients with subtalar dislocation, all of whom sustained violent trauma to the region of the ankle and hind foot. All but one patient were males. Clinically a subtalar dislocation resembles a complicated fracture dislocation of the ankle but a definitive diagnosis can only be made radiographically. The mechanism of injury and radiographic features of this injury are discussed.

  7. Open anterior dislocation of the hip in an adult: a case report and review of literature☆☆☆

    PubMed Central

    de Oliveira, Anderson Luiz; Machado, Eduardo Gomes

    2014-01-01

    Open anterior hip dislocation is a rare condition and results from high‐energy trauma. Ten cases of open anterior dislocation have been described in the literature so far. Its rarity is due to the inherent stability of the joint, its deep position in the pelvis, with strong ligaments and bulky muscles around the articulation. Several factors influence the prognosis, such as the degree of compounding, the associated soft tissue injuries, the age of the patient and, mainly, the delay in reduction. The main complications are: arthrosis of the hip, with incidence of 50% of cases, when associated with fractures of the femoral head; and osteonecrosis of the femoral head, with incidence between 1.7 and 40% (in closed anterior dislocation). Because of the rarity and the potential disability of this lesion, we report a case in a 46‐year‐old man, involved in an automobile accident. The hip was reduced (anterior superior dislocation) in the first three hours of the trauma. The patient was kept non‐weight bearing until sixth week, with complete weight bearing after 10th week. After one year follow‐up, the functional result was poor (Harris Hip Score: 52), probably because of the associated labral tear, but without signs of osteonecrosis of the femoral head in magnetic resonance imaging. PMID:26229781

  8. 20 CFR 663.820 - What are the eligibility requirements for adults to receive needs-related payments?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... adults to receive needs-related payments? 663.820 Section 663.820 Employees' Benefits EMPLOYMENT AND TRAINING ADMINISTRATION, DEPARTMENT OF LABOR ADULT AND DISLOCATED WORKER ACTIVITIES UNDER TITLE I OF THE WORKFORCE INVESTMENT ACT Supportive Services § 663.820 What are the eligibility requirements for adults...

  9. Honey bee workers that are pollen stressed as larvae become poor foragers and waggle dancers as adults.

    PubMed

    Scofield, Hailey N; Mattila, Heather R

    2015-01-01

    The negative effects on adult behavior of juvenile undernourishment are well documented in vertebrates, but relatively poorly understood in invertebrates. We examined the effects of larval nutritional stress on the foraging and recruitment behavior of an economically important model invertebrate, the honey bee (Apis mellifera). Pollen, which supplies essential nutrients to developing workers, can become limited in colonies because of seasonal dearths, loss of foraging habitat, or intensive management. However, the functional consequences of being reared by pollen-stressed nestmates remain unclear, despite growing concern that poor nutrition interacts with other stressors to exacerbate colony decline. We manipulated nurse bees' access to pollen and then assessed differences in weight, longevity, foraging activity, and waggle-dance behavior of the workers that they reared (who were co-fostered as adults). Pollen stress during larval development had far-reaching physical and behavioral effects on adult workers. Workers reared in pollen-stressed colonies were lighter and shorter lived than nestmates reared with adequate access to pollen. Proportionally fewer stressed workers were observed foraging and those who did forage started foraging sooner, foraged for fewer days, and were more likely to die after only a single day of foraging. Pollen-stressed workers were also less likely to waggle dance than their unstressed counterparts and, if they danced, the information they conveyed about the location of food was less precise. These performance deficits may escalate if long-term pollen limitation prevents stressed foragers from providing sufficiently for developing workers. Furthermore, the effects of brief pollen shortages reported here mirror the effects of other environmental stressors that limit worker access to nutrients, suggesting the likelihood of their synergistic interaction. Honey bees often experience the level of stress that we created, thus our findings

  10. Honey Bee Workers That Are Pollen Stressed as Larvae Become Poor Foragers and Waggle Dancers as Adults

    PubMed Central

    Scofield, Hailey N.; Mattila, Heather R.

    2015-01-01

    The negative effects on adult behavior of juvenile undernourishment are well documented in vertebrates, but relatively poorly understood in invertebrates. We examined the effects of larval nutritional stress on the foraging and recruitment behavior of an economically important model invertebrate, the honey bee (Apis mellifera). Pollen, which supplies essential nutrients to developing workers, can become limited in colonies because of seasonal dearths, loss of foraging habitat, or intensive management. However, the functional consequences of being reared by pollen-stressed nestmates remain unclear, despite growing concern that poor nutrition interacts with other stressors to exacerbate colony decline. We manipulated nurse bees’ access to pollen and then assessed differences in weight, longevity, foraging activity, and waggle-dance behavior of the workers that they reared (who were co-fostered as adults). Pollen stress during larval development had far-reaching physical and behavioral effects on adult workers. Workers reared in pollen-stressed colonies were lighter and shorter lived than nestmates reared with adequate access to pollen. Proportionally fewer stressed workers were observed foraging and those who did forage started foraging sooner, foraged for fewer days, and were more likely to die after only a single day of foraging. Pollen-stressed workers were also less likely to waggle dance than their unstressed counterparts and, if they danced, the information they conveyed about the location of food was less precise. These performance deficits may escalate if long-term pollen limitation prevents stressed foragers from providing sufficiently for developing workers. Furthermore, the effects of brief pollen shortages reported here mirror the effects of other environmental stressors that limit worker access to nutrients, suggesting the likelihood of their synergistic interaction. Honey bees often experience the level of stress that we created, thus our findings

  11. Starvation stress during larval development facilitates an adaptive response in adult worker honey bees (Apis mellifera L.).

    PubMed

    Wang, Ying; Kaftanoglu, Osman; Brent, Colin S; Page, Robert E; Amdam, Gro V

    2016-04-01

    Most organisms are constantly faced with environmental changes and stressors. In diverse organisms, there is an anticipatory mechanism during development that can program adult phenotypes. The adult phenotype would be adapted to the predicted environment that occurred during organism maturation. However, whether this anticipatory mechanism is present in eusocial species is questionable because eusocial organisms are largely shielded from exogenous conditions by their stable nest environment. In this study, we tested whether food deprivation during development of the honey bee (Apis mellifera), a eusocial insect model, can shift adult phenotypes to better cope with nutritional stress. After subjecting fifth instar worker larvae to short-term starvation, we measured nutrition-related morphology, starvation resistance, physiology, endocrinology and behavior in the adults. We found that the larval starvation caused adult honey bees to become more resilient toward starvation. Moreover, the adult bees were characterized by reduced ovary size, elevated glycogen stores and juvenile hormone (JH) titers, and decreased sugar sensitivity. These changes, in general, can help adult insects survive and reproduce in food-poor environments. Overall, we found for the first time support for an anticipatory mechanism in a eusocial species, the honey bee. Our results suggest that this mechanism may play a role in honey bee queen-worker differentiation and worker division of labor, both of which are related to the responses to nutritional stress. PMID:27030775

  12. Neurologic effects of solvents in older adults. (UW retired worker study). Final performance report

    SciTech Connect

    Daniell, W.E.

    1993-11-12

    The possibility that previous occupational exposure to solvents might be associated with clinically significant neurological dysfunction in older adults was investigated in a cross-sectional study. Subjects included 67 painters, 22 aerospace painters and fuel cell sealers, and a comparison group of 126 carpenters. All subjects had retired from regular employment at least 1 year prior to the study. As measured by semiquantitative exposure index, the cumulative histories of lifetime occupational solvent exposure were on the average comparable in the two exposed study groups, painters and aerospace workers. The carpenters differed from the other groups in solvent exposure by several orders of magnitude. The painters had a significantly higher history of consuming alcoholic beverages than did the other two study groups. The painters had a significantly higher score on the Beck Depression Inventory, a measure of current depressive symptoms. The painters reported significantly more general neurologic symptoms than did the other two groups. The aerospace workers showed much greater evidence of possible adverse effects from former solvent exposure on current neuropsychological function than did the painters when determined by reasoning and memory tests, memory visual motor speed and motor tests. No evidence of persistent effects on liver or renal excretory function was seen in solvent exposed subjects.

  13. 20 CFR 663.600 - What priority must be given to low-income adults and public assistance recipients served with...

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 20 Employees' Benefits 3 2010-04-01 2010-04-01 false What priority must be given to low-income adults and public assistance recipients served with adult funds under title I? 663.600 Section 663.600 Employees' Benefits EMPLOYMENT AND TRAINING ADMINISTRATION, DEPARTMENT OF LABOR ADULT AND DISLOCATED WORKER ACTIVITIES UNDER TITLE I OF THE...

  14. Current Concepts for Patellar Dislocation

    PubMed Central

    Petri, Maximilian; Ettinger, Max; Stuebig, Timo; Brand, Stephan; Krettek, Christian; Jagodzinski, Michael; Omar, Mohamed

    2015-01-01

    Context: Patellar dislocation usually occurs to the lateral side, leading to ruptures of the Medial Patellofemoral Ligament (MPFL) in about 90% of the cases. Even though several prognostic factors are identified for patellofemoral instability after patellar dislocation so far, the appropriate therapy remains a controversial issue. Evidence Acquisition: Authors searched the Medline library for studies on both surgical and conservative treatment for patellar dislocation and patellofemoral instability. Additionally, the reference list of each article was searched for additional studies. Results: A thorough analysis of the anatomical risk factors with a particular focus on patella alta, increased Tibial Tuberosity-Trochlear Groove (TT-TG) distance, trochlear dysplasia as well as torsional abnormalities should be performed early after the first dislocation to allow adequate patient counseling. Summarizing the results of all published randomized clinical trials and comparing surgical and conservative treatment after the first-time patellar dislocation until today indicated no significant evident difference for children, adolescents, and adults. Therefore, nonoperative treatment was indicated after a first-time patellar dislocation in the vast majority of patients. Conclusions: Surgical treatment for patellar dislocation is indicated primarily in case of relevant concomitant injuries such as osteochondral fractures, and secondarily for recurrent dislocations. PMID:26566512

  15. Knee Dislocations

    PubMed Central

    Schenck, Robert C.; Richter, Dustin L.; Wascher, Daniel C.

    2014-01-01

    Background: Traumatic knee dislocation is becoming more prevalent because of improved recognition and increased exposure to high-energy trauma, but long-term results are lacking. Purpose: To present 2 cases with minimum 20-year follow-up and a review of the literature to illustrate some of the fundamental principles in the management of the dislocated knee. Study Design: Review and case reports. Methods: Two patients with knee dislocations who underwent multiligamentous knee reconstruction were reviewed, with a minimum 20-year follow-up. These patients were brought back for a clinical evaluation using both subjective and objective measures. Subjective measures include the following scales: Lysholm, Tegner activity, visual analog scale (VAS), Short Form–36 (SF-36), International Knee Documentation Committee (IKDC), and a psychosocial questionnaire. Objective measures included ligamentous examination, radiographic evaluation (including Telos stress radiographs), and physical therapy assessment of function and stability. Results: The mean follow-up was 22 years. One patient had a vascular injury requiring repair prior to ligament reconstruction. The average assessment scores were as follows: SF-36 physical health, 52; SF-36 mental health, 59; Lysholm, 92; IKDC, 86.5; VAS involved, 10.5 mm; and VAS uninvolved, 2.5 mm. Both patients had excellent stability and were functioning at high levels of activity for their age (eg, hiking, skydiving). Both patients had radiographic signs of arthritis, which lowered 1 subject’s IKDC score to “C.” Conclusion: Knee dislocations have rare long-term excellent results, and most intermediate-term studies show fair to good functional results. By following fundamental principles in the management of a dislocated knee, patients can be given the opportunity to function at high levels. Hopefully, continued advances in the evaluation and treatment of knee dislocations will improve the long-term outcomes for these patients in the

  16. The Effects of Gender Segregation, Labor Force Participation, and Family Roles on the Earnings of Young Adult Workers.

    ERIC Educational Resources Information Center

    Witkowski, Kristine M.; Leicht, Kevin T.

    1995-01-01

    Analysis of data from 12,686 young adult workers demonstrated that men's wages benefited more from marriage, women's were constrained by dual marital/parental roles; detrimental effects of female-dominated occupations were more pronounced for single or childless married persons; married women experience social closure, sorting them into segregated…

  17. A Time Series Study of Factors Associated with Retention and Attrition of Older Adult Child-Care Workers. Final Report.

    ERIC Educational Resources Information Center

    Newman, Sally; Engel, Rafael; Ward, Christopher; Karip, Emin; Faux, Robert

    The work-related and personal factors associated with the willingness and ability of older adults to remain as child care workers and the factors associated with leaving child care work were studied in a time-series design. Subjects were 534 persons aged 50 years and older who were working for pay as child care providers. Of these, 341 replied to…

  18. Durability of Antibody Response Against Hepatitis B Virus in Healthcare Workers Vaccinated as Adults

    PubMed Central

    Gara, Naveen; Abdalla, Adil; Rivera, Elenita; Zhao, Xiongce; Werner, Jens M.; Liang, T. Jake; Hoofnagle, Jay H.; Rehermann, Barbara; Ghany, Marc G.

    2015-01-01

    Background. Follow-up studies of recipients of hepatitis B vaccine from endemic areas have reported loss of antibody to hepatitis B surface antigen (anti-HBs) in a high proportion of persons vaccinated at birth. In contrast, the long-term durability of antibody in persons vaccinated as adults in nonendemic areas is not well defined. We aimed to assess the durability of anti-HBs among healthcare workers (HCWs) vaccinated as adults and response to a booster among those without protective levels of antibody. Methods. Adult HCWs aged 18–60 at the time of initial vaccination were recruited. All were tested for hepatitis B surface antigen (HBsAg), antibody to hepatitis B core antigen (anti-HBc), and anti-HBs level. HCWs with anti-HBs <12 mIU/mL were offered a booster and levels were measured 1, 7, and 21 days afterward. Results. Anti-HBs levels were <12 mIU/mL in 9 of 50 (18%), 13 of 50 (26%), and 14 of 59 (24%) HCWs 10–15, 16–20, and >20 years postvaccination, respectively, (P = ns). Four HCWs were anti-HBc positive; none had HBsAg. By logistic regression, older age at vaccination was the only predictor of inadequate anti-HBs level (P = .0005). Thirty-four of 36 subjects with inadequate anti-HBs levels received a booster and 32 (94%) developed levels >12 mIU/mL within 3 weeks. Conclusions. Anti-HBs levels decrease after 10–31 years and fall below a level considered protective in approximately 25% of cases. The rapid and robust response to a booster vaccine suggests a long-lasting amnestic response. Hepatitis B vaccination provides long-term protection against hepatitis B and booster vaccination does not appear to be necessary in HCWs. Clinical Trials Registration. NCT01182311. PMID:25389254

  19. Women and Plant Closings: Unemployment, Reemployment, and Job Training Enrollment Following Dislocation.

    ERIC Educational Resources Information Center

    Smith, Suzanna D.; Price, Sharon J.

    Thousands of workers have been dislocated from jobs in the textile and apparel industries as a result of recessions and structural changes in the economy. Because of the large concentrations of female workers in these industries, women have been particularly vulnerable to dislocation. This study examined job dislocation and factors that affect…

  20. What adult worker model? A critical look at recent social policy reform in Europe from a gender and family perspective.

    PubMed

    Daly, Mary

    2011-01-01

    Analyses regularly feature claims that European welfare states are in the process of creating an adult worker model. The theoretical and empirical basis of this argument is examined here by looking first at the conceptual foundations of the adult worker model formulation and then at the extent to which social policy reform in western Europe fits with the argument. It is suggested that the adult worker formulation is under-specified. A framework incorporating four dimensions—the treatment of individuals vis-à-vis their family role and status for the purposes of social rights, the treatment of care, the treatment of the family as a social institution, and the extent to which gender inequality is problematized—is developed and then applied. The empirical analysis reveals a strong move towards individualization as social policy promotes and valorizes individual agency and self-sufficiency and shifts some childcare from the family. Yet evidence is also found of continued (albeit changed) familism. Rather than an unequivocal move to an individualized worker model then, a dual earner, gender-specialized, family arrangement is being promoted. The latter is the middle way between the old dependencies and the new “independence.” This makes for complexity and even ambiguity in policy, a manifestation of which is that reform within countries involves concurrent moves in several directions. PMID:21692242

  1. Legislative Side-By-side for The AEEG Act of Congressmen Kennedy and Hinojosa. WIA I and II & Related. To Advance the Recommendations of the National Commission On Adult Literacy and "Reach Higher, America"

    ERIC Educational Resources Information Center

    Council for Advancement of Adult Literacy (NJ1), 2009

    2009-01-01

    The purpose of this report is to help advance the recommendations of the National Commission on Adult Literacy, for the Adult Education and Economic Growth Act under development by Congressmen Patrick Kennedy and Reuben Hinojosa. Current law is compared to National Commission amendments in such areas as: Adult and Dislocated Worker Employment and…

  2. Deformable adult human phantoms for radiation protection dosimetry: anthropometric data representing size distributions of adult worker populations and software algorithms

    PubMed Central

    Na, Yong Hum; Zhang, Binquan; Zhang, Juying; Caracappa, Peter F; Xu, X George

    2012-01-01

    Computational phantoms representing workers and patients are essential in estimating organ doses from various occupational radiation exposures and medical procedures. Nearly all existing phantoms, however, were purposely designed to match internal and external anatomical features of the Reference Man as defined by the International Commission on Radiological Protection (ICRP). To reduce uncertainty in dose calculations caused by anatomical variations, a new generation of phantoms of varying organ and body sizes is needed. This paper presents detailed anatomical data in tables and graphs that are used to design such size-adjustable phantoms representing a range of adult individuals in terms of the body height, body weight and internal organ volume/mass. Two different sets of information are used to derive the phantom sets: (1) individual internal organ size and volume/mass distribution data derived from the recommendations of the ICRP in Publications 23 and 89 and (2) whole-body height and weight percentile data from the National Health and Nutrition Examination Survey (NHANES 1999–2002). The NHANES height and weight data for 19 year old males and females are used to estimate the distributions of individuals’ size, which is unknown, that corresponds to the ICRP organ and tissue distributions. This paper then demonstrates the usage of these anthropometric data in the development of deformable anatomical phantoms. A pair of phantoms—modeled entirely in mesh surfaces—of the adult male and female, RPI-adult male (AM) and RPI-adult female (AF) are used as the base for size-adjustable phantoms. To create percentile-specific phantoms from these two base phantoms, organ surface boundaries are carefully altered according to the tabulated anthropometric data. Software algorithms are developed to automatically match the organ volumes and masses with desired values. Finally, these mesh-based, percentile-specific phantoms are converted into voxel-based phantoms for Monte

  3. Deformable adult human phantoms for radiation protection dosimetry: anthropometric data representing size distributions of adult worker populations and software algorithms.

    PubMed

    Na, Yong Hum; Zhang, Binquan; Zhang, Juying; Caracappa, Peter F; Xu, X George

    2010-07-01

    Computational phantoms representing workers and patients are essential in estimating organ doses from various occupational radiation exposures and medical procedures. Nearly all existing phantoms, however, were purposely designed to match internal and external anatomical features of the Reference Man as defined by the International Commission on Radiological Protection (ICRP). To reduce uncertainty in dose calculations caused by anatomical variations, a new generation of phantoms of varying organ and body sizes is needed. This paper presents detailed anatomical data in tables and graphs that are used to design such size-adjustable phantoms representing a range of adult individuals in terms of the body height, body weight and internal organ volume/mass. Two different sets of information are used to derive the phantom sets: (1) individual internal organ size and volume/mass distribution data derived from the recommendations of the ICRP in Publications 23 and 89 and (2) whole-body height and weight percentile data from the National Health and Nutrition Examination Survey (NHANES 1999-2002). The NHANES height and weight data for 19 year old males and females are used to estimate the distributions of individuals' size, which is unknown, that corresponds to the ICRP organ and tissue distributions. This paper then demonstrates the usage of these anthropometric data in the development of deformable anatomical phantoms. A pair of phantoms--modeled entirely in mesh surfaces--of the adult male and female, RPI-adult male (AM) and RPI-adult female (AF) are used as the base for size-adjustable phantoms. To create percentile-specific phantoms from these two base phantoms, organ surface boundaries are carefully altered according to the tabulated anthropometric data. Software algorithms are developed to automatically match the organ volumes and masses with desired values. Finally, these mesh-based, percentile-specific phantoms are converted into voxel-based phantoms for Monte Carlo

  4. Deformable adult human phantoms for radiation protection dosimetry: anthropometric data representing size distributions of adult worker populations and software algorithms

    NASA Astrophysics Data System (ADS)

    Hum Na, Yong; Zhang, Binquan; Zhang, Juying; Caracappa, Peter F.; Xu, X. George

    2010-07-01

    Computational phantoms representing workers and patients are essential in estimating organ doses from various occupational radiation exposures and medical procedures. Nearly all existing phantoms, however, were purposely designed to match internal and external anatomical features of the Reference Man as defined by the International Commission on Radiological Protection (ICRP). To reduce uncertainty in dose calculations caused by anatomical variations, a new generation of phantoms of varying organ and body sizes is needed. This paper presents detailed anatomical data in tables and graphs that are used to design such size-adjustable phantoms representing a range of adult individuals in terms of the body height, body weight and internal organ volume/mass. Two different sets of information are used to derive the phantom sets: (1) individual internal organ size and volume/mass distribution data derived from the recommendations of the ICRP in Publications 23 and 89 and (2) whole-body height and weight percentile data from the National Health and Nutrition Examination Survey (NHANES 1999-2002). The NHANES height and weight data for 19 year old males and females are used to estimate the distributions of individuals' size, which is unknown, that corresponds to the ICRP organ and tissue distributions. This paper then demonstrates the usage of these anthropometric data in the development of deformable anatomical phantoms. A pair of phantoms—modeled entirely in mesh surfaces—of the adult male and female, RPI-adult male (AM) and RPI-adult female (AF) are used as the base for size-adjustable phantoms. To create percentile-specific phantoms from these two base phantoms, organ surface boundaries are carefully altered according to the tabulated anthropometric data. Software algorithms are developed to automatically match the organ volumes and masses with desired values. Finally, these mesh-based, percentile-specific phantoms are converted into voxel-based phantoms for Monte

  5. 20 CFR 663.820 - What are the eligibility requirements for adults to receive needs-related payments?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 20 Employees' Benefits 3 2010-04-01 2010-04-01 false What are the eligibility requirements for adults to receive needs-related payments? 663.820 Section 663.820 Employees' Benefits EMPLOYMENT AND TRAINING ADMINISTRATION, DEPARTMENT OF LABOR ADULT AND DISLOCATED WORKER ACTIVITIES UNDER TITLE I OF THE WORKFORCE INVESTMENT ACT Supportive Services...

  6. The Workforce Paradox for Adults with Limited Literacy or English Language Proficiency: A Report from the Field.

    ERIC Educational Resources Information Center

    Pinkey, Diane; Hofer, Judy

    Under the 1998 Workforce Investment Act (WIA), One Stop Career Centers were developed to provide training and employment related services to adults, youths, and dislocated workers. This study investigated the extent to which adults with limited literacy and/or English language skills were being served at One Stop Career Centers in New Mexico. Data…

  7. 20 CFR 663.230 - What criteria must be used to determine whether an employed worker needs intensive services to...

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 20 Employees' Benefits 3 2010-04-01 2010-04-01 false What criteria must be used to determine whether an employed worker needs intensive services to obtain or retain employment leading to âself-sufficiencyâ? 663.230 Section 663.230 Employees' Benefits EMPLOYMENT AND TRAINING ADMINISTRATION, DEPARTMENT OF LABOR ADULT AND DISLOCATED...

  8. Trade Adjustment Assistance: Trends, Outcomes, and Management Issues in Dislocated Worker Programs. Report to the Chairman and Ranking Minority Member, Committee on Finance, U.S. Senate.

    ERIC Educational Resources Information Center

    Westin, Susan S.

    To assess the effectiveness of the Trade Adjustment Assistance and North American Free Trade Agreement (NAFTA) Transitional Adjustment Assistance programs, the General Accounting Office (GAO) reviewed available Department of Labor program data and surveyed 20 states representing about 76% of all workers certified under the two programs in fiscal…

  9. Promoting safer sexual practices among young adults: a survey of health workers in Moshi Rural District, Tanzania.

    PubMed

    Ngomuo, E T; Klepp, K I; Rise, J; Mnyika, K S

    1995-01-01

    As part of the national effort to prevent further spread of HIV/AIDS, rural health workers in Tanzania are asked to promote safer sex practices among the sexually active population. We conducted a survey among health workers in Moshi Rural District, Kilimanjaro, designed to assess their attitudes, perceived norms and self-efficacy with respect to the promotion of safer sexual practices among young adults 15-35 years old. Health workers at all private and governmental health facilities were included (n = 342; participation rate of 68.4%). We observed relatively strong associations between the frequency and quality of reported counselling behaviour and perceived norms, attitudes and self-efficacy (standardized regression coefficients (beta) of 0.329, 0.252 and 0.159 respectively). In addition, exposure to behaviour change strategies during formal training and marital status of the health workers were associated with counselling behaviour (beta of 0.133 and 0.118 respectively). Overall, these factors accounted for 40.8% of the observed variance in reported counselling behaviour. It is recommended that continued education for health workers focus on providing normative support for promoting safer sex, provide information which may help foster positive attitudes and teach practical counselling skills to further increase the self-efficacy regarding counselling young people. PMID:8547364

  10. Atraumatic Anterior Dislocation of the Hip Joint

    PubMed Central

    Ohtsuru, Tadahiko; Morita, Yasuyuki; Murata, Yasuaki; Itou, Junya; Morita, Yuji; Munakata, Yutaro; Kato, Yoshiharu

    2015-01-01

    Dislocation of the hip joint in adults is usually caused by high-energy trauma such as road traffic accidents or falls from heights. Posterior dislocation is observed in most cases. However, atraumatic anterior dislocation of the hip joint is extremely rare. We present a case of atraumatic anterior dislocation of the hip joint that was induced by an activity of daily living. The possible causes of this dislocation were anterior capsule insufficiency due to developmental dysplasia of the hip, posterior pelvic tilt following thoracolumbar kyphosis due to vertebral fracture, and acetabular anterior coverage changes by postural factor. Acetabular anterior coverage changes in the sagittal plane were measured using a tomosynthesis imaging system. This system was useful for elucidation of the dislocation mechanism in the present case. PMID:26819791

  11. Breaking New Ground: The Development of Adult and Workers' Education in North America. Proceedings from the Syracuse University Kellogg Project's Visiting Scholar Conference in the History of Adult Education (1st, Syracuse, New York, March 1989).

    ERIC Educational Resources Information Center

    Rohfield, Rae Wahl, Ed.

    The 19 papers in this conference report examine the formative period of the field of adult education, the development of workers' education, and the interrelationships of the two fields. The four papers in Section I, on defining adult education are: "Challenging the System: The Adult Education Movement and the Educational Bureaucracy of the 1920s"…

  12. Adult Education in a Workplace Context: Recognising Production Workers' Responses and Partnership Challenges

    ERIC Educational Resources Information Center

    Wärvik, Gun-Britt

    2016-01-01

    This article is about a larger regional Swedish partnership programme that was established to develop site-based education for production workers. A partnership is seen as composed of different practice architectures. The actors involved represented larger transnational as well as smaller manufacturing companies, employers, the metal workers'…

  13. Ipsilateral Traumatic Posterior Hip Dislocation, Posterior Wall and Transverse Acetabular Fracture with Trochanteric Fracture in an adult: Report of First Case

    PubMed Central

    Sinha, Skand; Naik, Ananta k; Arya, Rajendra K; Jain, Vijay K

    2013-01-01

    Introduction: Posterior dislocation of the hip joint with associated acetabular and intertrochanteric fracture is a complex injury. Early recognition, prompt and stable reduction is needed of successful outcome. Case Report: 45 year old male patient presented with posterior dislocation of the hip with transverse fracture with posterior wall fracture of acetabulam and intertrochanteric fracture on the ipsilateral side. The complex fracture geometry was confirmed by CT scan. The patient was successfully managed by open reduction and internal fixation of intertrochanteric fracture was achieved with dynamic hip screw (DHS) plate fixation followed by fixation of acetabular fracture with reconstruction plate. Conclusion: Hip dislocation combined with acetabular fracture is an uncommon injury; this article presents a unique case of posterior wall and transverse fractures of ipsilateral acetabulum with intertrochanteric fracture in a patient who sustained traumatic posterior hip dislocation. Early surgical intervention is important for satisfactory outcomes of such complex fracture-dislocation injuries. PMID:27298928

  14. Differential antennal proteome comparison of adult honeybee drone, worker and queen (Apis mellifera L.).

    PubMed

    Fang, Yu; Song, Feifei; Zhang, Lan; Aleku, Dereje Woltedji; Han, Bin; Feng, Mao; Li, Jianke

    2012-01-01

    To understand the olfactory mechanism of honeybee antennae in detecting specific volatile compounds in the atmosphere, antennal proteome differences of drone, worker and queen were compared using 2-DE, mass spectrometry and bioinformatics. Therefore, 107 proteins were altered their expressions in the antennae of drone, worker and queen bees. There were 54, 21 and 32 up-regulated proteins in the antennae of drone, worker and queen, respectively. Proteins upregulated in the drone antennae were involved in fatty acid metabolism, antioxidation, carbohydrate metabolism and energy production, protein folding and cytoskeleton. Proteins upregulated in the antennae of worker and queen bees were related to carbohydrate metabolism and energy production while molecular transporters were upregulated in the queen antennae. Our results explain the role played by the antennae of drone is to aid in perceiving the queen sexual pheromones, in the worker antennae to assist for food search and social communication and in the queen antennae to help pheromone communication with the worker and the drone during the mating flight. This first proteomic study significantly extends our understanding of honeybee olfactory activities and the possible mechanisms played by the antennae in response to various environmental, social, biological and biochemical signals. PMID:21982827

  15. Starvation stress during larval development reveals predictive adaptive response in adult worker honey bees (Apis mellifera)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A variety of organisms exhibit developmental plasticity that results in differences in adult morphology, physiology or behavior. This variation in the phenotype, called “Predictive Adaptive Response (PAR),” gives a selective advantage in an adult's environment if the adult experiences environments s...

  16. ADULT EDUCATION FOR MIGRANT AND SEASONAL FARM WORKERS. PROJECT REPORT, JUNE 12 - SEPTEMBER 1, 1967.

    ERIC Educational Resources Information Center

    MAURER, WAYNE F.

    THE CHIEF PURPOSE OF ADULT MIGRANT EDUCATION, AS DISCUSSED IN THIS REPORT, IS TO ELIMINATE POVERTY BY PREPARING THE MIGRANT FOR PROFITABLE PARTICIPATION IN SOCIETY. THE FLORIDA STATE DEPARTMENT OF EDUCATION STATES THAT THE PURPOSE OF THE IMMOKALEE MIGRANT ADULT EDUCATION PROJECT IS TO PROVIDE ADULT BASIC EDUCATION AND PRE-VOCATIONAL EXPERIENCES…

  17. Isolated Carpo-Metacarpal Dislocation of the Thumb

    PubMed Central

    Suresh, SS; Zaki, Hosam; Ahmed, Aamir

    2012-01-01

    Introduction: Isolated dislocations of the trapezio metacarpal joint without associated fracture has been reported very rarely in the literature. There are reports of associated injuries like fracture of the trapezium, dislocation of the metacarpophalangeal joint and fractures of the base of the thumb metacarpal. Case Report: Authors report a case of isolated carpometacarpal dislocation of the right thumb, in an adult, successfully managed conservatively. At 15 months follow up the patient had full function of the hand without any clinical or radiological evidence of instability or posttraumatic arthritis. Conclusion: Isolated dislocations can be successfully managed by closed reduction and immobilization in a back slab, with unstable dislocations requiring surgical intervention.

  18. Dislocation motion and instability

    NASA Astrophysics Data System (ADS)

    Zhu, Yichao; Chapman, Stephen Jonathan; Acharya, Amit

    2013-08-01

    The Peach-Koehler expression for the stress generated by a single (non-planar) curvilinear dislocation is evaluated to calculate the dislocation self stress. This is combined with a law of motion to give the self-induced motion of a general dislocation curve. A stability analysis of a rectilinear, uniformly translating dislocation is then performed. The dislocation is found to be susceptible to a helical instability, with the maximum growth rate occurring when the dislocation is almost, but not exactly, pure screw. The non-linear evolution of the instability is determined numerically, and implications for slip band formation and non-Schmid behavior in yielding are discussed.

  19. Examining a Proposed Job Retention Model for Adult Workers with Mental Retardation

    ERIC Educational Resources Information Center

    Fornes, Sandra L.

    2008-01-01

    This research provides an analysis of factors predicting job retention (JR), job satisfaction (JS), and job performance (JP) of workers with mental retardation (MR). The findings highlight self-determination as a critical skill in influencing three important employee's outcomes, JR, JS, and JP. The intent of the study was to develop job retention…

  20. Adult Education for Industrial Workers; The Contribution of Sheffield University Extramural Department.

    ERIC Educational Resources Information Center

    Brown, Michael Barratt

    Focusing on efforts to devise recruitment and teaching methods relevant to British industrial workers, an account is given of the day release time courses provided by the Sheffield University Extramural Department in association with trade unions and management among miners, steelworkers, and technologists in South Derbyshire, South Yorkshire, and…

  1. Critical Adult Learning of Asian Immigrant Workers: A Social Network Perspective

    ERIC Educational Resources Information Center

    Lee, Mosung; Madyun, Na'im

    2008-01-01

    This study reveals how the social networks of immigrant workers play a key role in mediating critical learning towards a particular political attitude. Theoretical relationships between critical learning and political attitudes were set up and four types of political attitudes were identified. A "resistant political attitude" was conceptually…

  2. Muscarinic regulation of Kenyon cell dendritic arborizations in adult worker honey bees.

    PubMed

    Dobrin, Scott E; Herlihy, J Daniel; Robinson, Gene E; Fahrbach, Susan E

    2011-09-01

    The experience of foraging under natural conditions increases the volume of mushroom body neuropil in worker honey bees. A comparable increase in neuropil volume results from treatment of worker honey bees with pilocarpine, an agonist for muscarinic-type cholinergic receptors. A component of the neuropil growth induced by foraging experience is growth of dendrites in the collar region of the calyces. We show here, via analysis of Golgi-impregnated collar Kenyon cells with wedge arborizations, that significant increases in standard measures of dendritic complexity were also found in worker honey bees treated with pilocarpine. This result suggests that signaling via muscarinic-type receptors promotes the increase in Kenyon cell dendritic complexity associated with foraging. Treatment of worker honey bees with scopolamine, a muscarinic inhibitor, inhibited some aspects of dendritic growth. Spine density on the Kenyon cell dendrites varied with sampling location, with the distal portion of the dendritic field having greater total spine density than either the proximal or medial section. This observation may be functionally significant because of the stratified organization of projections from visual centers to the dendritic arborizations of the collar Kenyon cells. Pilocarpine treatment had no effect on the distribution of spines on dendrites of the collar Kenyon cells. PMID:21262388

  3. Reframing the Public in Public Education: The Landless Workers Movement (MST) and Adult Education in Brazil

    ERIC Educational Resources Information Center

    Thapliyal, Nisha

    2013-01-01

    Education for rural Brazilians has historically been dominated by two imperatives: human capital and political patronage. For the last four decades, the Landless Workers Movement (MST) have maintained a struggle to democratise public education and democracy itself. In this article, I make a situated analysis of the educational politics of the MST…

  4. Dislocated shoulder - aftercare

    MedlinePlus

    Shoulder dislocation - aftercare; Shoulder subluxation - aftercare; Shoulder reduction - aftercare ... You most likely dislocated your shoulder from a sports injury or accident, such as a fall. You have likely injured (stretched or torn) some of the muscles, ...

  5. Dislocated shoulder - aftercare

    MedlinePlus

    Shoulder dislocation - aftercare; Shoulder subluxation - aftercare; Shoulder reduction - aftercare ... Horn AE, Ufberg JW. Management of common dislocations. In: ... Extremity 6th ed. Philadelphia, PA: ElsevierMosby; 2011:chap 92.

  6. Temporomandibular joint dislocation.

    PubMed

    Sharma, Naresh Kumar; Singh, Akhilesh Kumar; Pandey, Arun; Verma, Vishal; Singh, Shreya

    2015-01-01

    Temporomandibular joint (TMJ) dislocation is an uncommon but debilitating condition of the facial skeleton. The condition may be acute or chronic. Acute TMJ dislocation is common in clinical practice and can be managed easily with manual reduction. Chronic recurrent TMJ dislocation is a challenging situation to manage. In this article, we discuss the comprehensive review of the different treatment modalities in managing TMJ dislocation. PMID:26668447

  7. Temporomandibular joint dislocation

    PubMed Central

    Sharma, Naresh Kumar; Singh, Akhilesh Kumar; Pandey, Arun; Verma, Vishal; Singh, Shreya

    2015-01-01

    Temporomandibular joint (TMJ) dislocation is an uncommon but debilitating condition of the facial skeleton. The condition may be acute or chronic. Acute TMJ dislocation is common in clinical practice and can be managed easily with manual reduction. Chronic recurrent TMJ dislocation is a challenging situation to manage. In this article, we discuss the comprehensive review of the different treatment modalities in managing TMJ dislocation. PMID:26668447

  8. Live-in Care Workers in Sheltered Housing for Older Adults in Israel: The New Sheltered Housing Law.

    PubMed

    Iecovich, Esther

    2016-01-01

    Supportive housing schemes were historically aimed to provide group accommodation for older adults. With the aging of residents, facilities were required to enable them to receive care services in order to allow them to age in place. Thus, different countries and different facilities developed different models of housing with care, reflecting cultural and policy diversities. Despite all of the different models, there are many commonalities among the supportive housing schemes across countries. These include provision of dwelling units and care services provided by either the facility or by external agencies. The aims of this article are threefold: to describe the historical development of the ever-evolving supportive care housing phenomena; to point at variations in models of housing and care within the international context; and to present a new Israeli model that enables residents to privately hire live-in care workers to meet their care needs. This is a unique model in the international context that has not been reported before. The article describes the main ideas of the new model and discusses the challenges that it raises and pinpoints the unresolved issues associated with the presence of live-in care workers employed by residents of sheltered housing that should be addressed. PMID:26959294

  9. Where Are the Adults? The Attitudes of Parents, Teachers, Clergy, Coaches, and Youth Workers on Teen Pregnancy. A Focus Group Report.

    ERIC Educational Resources Information Center

    National Campaign To Prevent Teen Pregnancy, Washington, DC.

    In 1997, the National Campaign To Prevent Teen Pregnancy convened nine focus groups of parents of teens and other adults who work with teens such as teachers, clergy, coaches, youth recreation specialists, youth-serving organization staff, and community outreach workers. This report publishes the results of these focus groups, which involved 57…

  10. Economic Competition, Restructuring and Worker Dislocation.

    ERIC Educational Resources Information Center

    Blalock, Ann Bonar, Ed.

    1995-01-01

    In this issue various concepts of economic change are examined. Part I looks at economic change as a context for focusing on workforce issues. Parts II and III discuss what is being done to address this contemporary problem. This issue contains the following papers: "Presidential Perspectives on Economic Change and Restructuring: An…

  11. Family and Career Transitions Resource Guide (FACT). A Resource Guide for Use in Adult Job Readiness and Single Parent Homemaker Instructional Programs.

    ERIC Educational Resources Information Center

    Ohio State Dept. of Education, Columbus. Div. of Vocational and Career Education.

    This resource guide introduces a curriculum designed to help instructors meet the needs of special adult audiences--displaced homemakers, single parents, dislocated workers, and economically depressed families. It is organized according to four practical problems: (1) personal development; (2) career exploration; (3) employability; and (4)…

  12. Farm Activities and Agricultural Injuries in Youth and Young Adult Workers.

    PubMed

    DeWit, Yvonne; Pickett, William; Lawson, Joshua; Dosman, James

    2015-01-01

    Youth and young adults who work in the agricultural sector experience high rates of injury. This study aimed to investigate relations between high-risk farm activities and the occurrence of agricultural injuries in these vulnerable groups. A cross-sectional analysis was conducted using written questionnaire data from 1135 youth and young adults from the Saskatchewan Farm Injury Cohort. The prevalence of agricultural injury was estimated at 4.9%/year (95% confidence interval [CI]: 3.7, 6.2). After adjustment for important covariates, duration of farm work was strongly associated with the occurrence of injury (risk ratio [RR] = 8.0 [95% CI: 1.7, 36.7] for 10-34 vs. <10 hours/week; RR = 10.3 [95% CI: 2.2, 47.5] for those working 35+ hours/week). Tractor maintenance, tractor operation, chores with large animals, herd maintenance activities, and veterinary activities were identified as risk factors for agricultural injury. Risks for agricultural injury among youth and young adults on farms relate directly to the amounts and types of farm work exposures that young people engage in. PMID:26237722

  13. Dislocation Formation in Alloys

    NASA Astrophysics Data System (ADS)

    Minami, Akihiko; Onuki, Akira

    2006-05-01

    An interaction between dislocations and phase transitions is studied by a phase field model both in two and three dimensional systems. Our theory is a simple extension of the traditional linear elastic theory, and the elastic energy is a periodic function of local strains which is reflecting the periodicity of crystals. We find that the dislocations are spontaneously formed by quenching. Dislocations are formed from the interface of binary alloys, and slips are preferentially gliding into the soft metals. In three dimensional systems, formation of dislocations under applied strain is studied in two phase state. We find that the dislocation loops are created from the surface of hard metals. We also studied the phase separation above the coexisting temperature which is called as the Cottrell atmosphere. Clouds of metals cannot catch up with the motion of dislocations at highly strained state.

  14. Alcohol Policy Comprehension, Compliance and Consequences Among Young Adult Restaurant Workers

    PubMed Central

    Ames, Genevieve M.; Cunradi, Carol B.; Duke, Michael R.

    2012-01-01

    SUMMARY This study explores relationships between young adult restaurant employees' understanding and compliance with workplace alcohol control policies and consequences of alcohol policy violation. A mixed method analysis of 67 semi-structured interviews and 1,294 telephone surveys from restaurant chain employees found that alcohol policy details confused roughly a third of employees. Among current drinkers (n=1,093), multivariable linear regression analysis found that frequency of alcohol policy violation was positively associated with frequency of experiencing problems at work; perceived supervisor enforcement of alcohol policy was negatively associated with this outcome. Implications for preventing workplace alcohol-related problems include streamlining confusing alcohol policy guidelines. PMID:22984360

  15. 20 CFR 671.110 - What are major economic dislocations or other events which may qualify for a national emergency...

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 20 Employees' Benefits 4 2012-04-01 2012-04-01 false What are major economic dislocations or other events which may qualify for a national emergency grant? 671.110 Section 671.110 Employees' Benefits... DISLOCATED WORKERS § 671.110 What are major economic dislocations or other events which may qualify for...

  16. 20 CFR 671.110 - What are major economic dislocations or other events which may qualify for a national emergency...

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 20 Employees' Benefits 4 2014-04-01 2014-04-01 false What are major economic dislocations or other events which may qualify for a national emergency grant? 671.110 Section 671.110 Employees' Benefits... DISLOCATED WORKERS § 671.110 What are major economic dislocations or other events which may qualify for...

  17. 20 CFR 671.110 - What are major economic dislocations or other events which may qualify for a national emergency...

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 20 Employees' Benefits 4 2013-04-01 2013-04-01 false What are major economic dislocations or other events which may qualify for a national emergency grant? 671.110 Section 671.110 Employees' Benefits... DISLOCATED WORKERS § 671.110 What are major economic dislocations or other events which may qualify for...

  18. Nutrient balancing of the adult worker bumblebee (Bombus terrestris) depends on the dietary source of essential amino acids

    PubMed Central

    Stabler, Daniel; Paoli, Pier P.; Nicolson, Susan W.; Wright, Geraldine A.

    2015-01-01

    ABSTRACT Animals carefully regulate the amount of protein that they consume. The quantity of individual essential amino acids (EAAs) obtained from dietary protein depends on the protein source, but how the proportion of EAAs in the diet affects nutrient balancing has rarely been studied. Recent research using the Geometric Framework for Nutrition has revealed that forager honeybees who receive much of their dietary EAAs from floral nectar and not from solid protein have relatively low requirements for dietary EAAs. Here, we examined the nutritional requirements for protein and carbohydrates of foragers of the buff-tailed bumblebee Bombus terrestris. By using protein (sodium caseinate) or an equimolar mixture of the 10 EAAs, we found that the intake target (nutritional optimum) of adult workers depended on the source and proportion of dietary EAAs. When bees consumed caseinate-containing diets in a range of ratios between 1:250 and 1:25 (protein to carbohydrate), they achieved an intake target (IT) of 1:149 (w/w). In contrast to those fed protein, bees fed the EAA diets had an IT more biased towards carbohydrates (1:560 w/w) but also had a greater risk of death than those fed caseinate. We also tested how the dietary source of EAAs affected free AAs in bee haemolymph. Bees fed diets near their IT had similar haemolymph AA profiles, whereas bees fed diets high in caseinate had elevated levels of leucine, threonine, valine and alanine in the haemolymph. We found that like honeybees, bumblebee workers prioritize carbohydrate intake and have a relatively low requirement for protein. The dietary source of EAAs influenced both the ratio of protein/EAA to carbohydrate and the overall amount of carbohydrate eaten. Our data support the idea that EAAs and carbohydrates in haemolymph are important determinants of nutritional state in insects. PMID:25617453

  19. Do normal hips dislocate?

    PubMed

    Alshameeri, Zeiad; Rehm, Andreas

    2014-11-01

    There have been a small number of case reports describing late normal-hip dislocations in children who were later diagnosed with developmental dysplasia of the hip. Here, we contest the assumption that normal hips can dislocate. We argue that (as in our case) the ultrasound scans in all published case reports on late dislocated normal hips did not show results that were entirely normal and therefore, so far, there has been no convincing evidence of a dislocation of a normal hip. We also want to highlight the importance of meticulous ultrasound and clinical assessments of high-risk children by an experienced orthopaedic surgeon. PMID:25144883

  20. Metallurgy: Starting and stopping dislocations

    NASA Astrophysics Data System (ADS)

    Minor, Andrew M.

    2015-09-01

    A comparison of dislocation dynamics in two hexagonal close-packed metals has revealed that dislocation movement can vary substantially in materials with the same crystal structure, associated with how the dislocations relax when stationary.

  1. Trans-Scaphoid Perilunate Fracture Dislocation; A Technical Note

    PubMed Central

    Aslani, Hossein; Bazavar, Mohammad Reza; Sadighi, Ali; Tabrizi, Ali; Elmi, Asghar

    2016-01-01

    Carpal fracture-dislocation is regarded as an unusual orthopedic injury and, thus, orthopedic surgeons are less experienced in dealing with and treating these fractures and dislocations. We report a 20-year-old worker man suffering from an unusual carpal fracture-dislocation. There was trans-scaphoid fracture and lunate dislocation with other carpal proximal bones toward volar of the wrist. Two volar and dorsal approaches were used to treat and stabilize the fracture. It was completely stabilized after open reduction and fixation using several pins. After two days, neural symptoms were completely recovered and the patient was discharged. Postoperative radiographies revealed complete restitution of lesser and greater arcs and normalization of Gilula's line. Scapholunate and lunatocapitate angles reached to less than 60° and 10°, respectively. The combined approach had favorable results for treatment of this unusual type of carpus fracture dislocation. However longer follow up is need to evaluate the arthritis and degenerative changes in wrist. PMID:27331069

  2. Dislocation in Spoken French.

    ERIC Educational Resources Information Center

    Calve, Pierre

    1985-01-01

    Discusses dislocation, a construction in which one element, usually a noun, is isolated either at the beginning or at the end of a sentence while being represented in the body of the sentence by a pronoun. Discusses the place of dislocation in linguistic studies and its pedagogical implications. (SED)

  3. Dislocations in yttrium orthovanadate

    NASA Astrophysics Data System (ADS)

    Eakins, D. E.; LeBret, J. B.; Norton, M. G.; Bahr, D. F.

    2004-06-01

    Dislocation structures in single crystals of yttrium orthovanadate have been identified by transmission electron microscopy. Electron diffraction was used to predict possible Burgers vectors for the dislocations. Results suggest vectors of the type {1}/{2}[1 1 1] or {1}/{4}[0 2 1] . Arguments for the likelihood of each possible vector have been presented.

  4. Parallel Dislocation Simulator

    2006-10-30

    ParaDiS is software capable of simulating the motion, evolution, and interaction of dislocation networks in single crystals using massively parallel computer architectures. The software is capable of outputting the stress-strain response of a single crystal whose plastic deformation is controlled by the dislocation processes.

  5. Leg lengthening of more than 5 cm is a risk factor for sciatic nerve injury after total hip arthroplasty for adult hip dislocation

    PubMed Central

    Higuchi, Yoshitoshi; Hasegawa, Yukiharu; Ishiguro, Naoki

    2015-01-01

    ABSTRACT Total hip arthroplasty (THA) in patients with high hip dislocation is challenging and technically demanding. Nerve injury is a problem associated with leg lengthening after THA. The purpose of this study was to identify the risk factors for sciatic nerve injury after THA in patients with high hip dislocation. Thirty-seven patients (41 THAs) with Crowe type IV hips were consecutively treated. The average leg lengthening (LL) was 3.2 cm. The average Harris hip score was improved from 57.5 points to 83.1 points at the final follow-up. The clinical outcomes after an average 6.4-years follow-up were satisfactory. Sciatic nerve injury was observed in two joints. LL in the two joints (two patients) with sciatic nerve injury was 5.2 cm and 6.7 cm, respectively. Leg lengthening of >5 cm was a risk factor for sciatic nerve injury. Therefore, leg lengthening of >5 cm should be avoided to prevent sciatic nerve injury. PMID:26412892

  6. Xenobiotic Effects on Intestinal Stem Cell Proliferation in Adult Honey Bee (Apis mellifera L) Workers

    PubMed Central

    Forkpah, Cordelia; Dixon, Luke R.; Fahrbach, Susan E.; Rueppell, Olav

    2014-01-01

    The causes of the current global decline in honey bee health are unknown. One major group of hypotheses invokes the pesticides and other xenobiotics to which this important pollinator species is often exposed. Most studies have focused on mortality or behavioral deficiencies in exposed honey bees while neglecting other biological functions and target organs. The midgut epithelium of honey bees presents an important interface between the insect and its environment. It is maintained by proliferation of intestinal stem cells throughout the adult life of honey bees. We used caged honey bees to test multiple xenobiotics for effects on the replicative activity of the intestinal stem cells under laboratory conditions. Most of the tested compounds did not alter the replicative activity of intestinal stem cells. However, colchicine, methoxyfenozide, tetracycline, and a combination of coumaphos and tau-fluvalinate significantly affected proliferation rate. All substances except methoxyfenozide decreased proliferation rate. Thus, the results indicate that some xenobiotics frequently used in apiculture and known to accumulate in honey bee hives may have hitherto unknown physiological effects. The nutritional status and the susceptibility to pathogens of honey bees could be compromised by the impacts of xenobiotics on the maintenance of the midgut epithelium. This study contributes to a growing body of evidence that more comprehensive testing of xenobiotics may be required before novel or existing compounds can be considered safe for honey bees and other non-target species. PMID:24608542

  7. Electromechanical simulations of dislocations

    NASA Astrophysics Data System (ADS)

    Skiba, Oxana; Gracie, Robert; Potapenko, Stanislav

    2013-04-01

    Improving the reliability of micro-electronic devices depends in part on developing a more in-depth understanding of dislocations because dislocations are barriers to charge carriers. To this end, the quasi-static simulation of discrete dislocations dynamics in materials under mechanical and electrical loads is presented. The simulations are based on the extended finite element method, where dislocations are modelled as internal discontinuities. The strong and weak forms of the boundary value problem for the coupled system are presented. The computation of the Peach-Koehler force using the J-integral is discussed. Examples to illustrate the accuracy of the simulations are presented. The motion of the network of the dislocations under different electrical and mechanical loads is simulated. It was shown that even in weak piezoelectric materials the effect of the electric field on plastic behaviour is significant.

  8. Electronic properties of dislocations

    NASA Astrophysics Data System (ADS)

    Reiche, M.; Kittler, M.; Uebensee, H.; Pippel, E.; Haehnel, A.; Birner, S.

    2016-04-01

    Dislocations exhibit a number of exceptional electronic properties resulting in a significant increase in the drain current of MOSFETs if defined numbers of these defects are placed in the channel. Measurements on individual dislocations in Si refer to a supermetallic conductivity. A model of the electronic structure of dislocations is proposed based on experimental measurements and tight-binding simulations. It is shown that the high strain level on the dislocation core—exceeding 10 % or more—causes locally dramatic changes in the band structure and results in the formation of a quantum well along the dislocation line. This explains experimental findings (two-dimensional electron gas, single-electron transitions). The energy quantization within the quantum well is most important for supermetallic conductivity.

  9. Participation in the Women, Infants, and Children (WIC) Program as Reported by Documented and Undocumented Farm Worker Adults in the Households.

    PubMed

    Leigh, J Paul; Medel-Herrero, Alvaro

    2015-01-01

    Debate surrounds the provision of Women, Infants, and Children (WIC) benefits to undocumented immigrants. Few studies are available to estimate use of WIC services by documented and undocumented households using nationally representative data. The authors analyzed data from the National Agricultural Workers Survey (NAWS) annual cross-sections from 1993 through 2009 (N = 40,896 person-years). Household documentation status is defined by the status of the adults in the household, not children. Simple mean differences, logistic regressions, and time charts described household participation in WIC over 2-year intervals. Without adjustments for covariates, 10.7% of undocumented farm workers' households and 12.4% of documented households received WIC benefits, yielding an odds ratio of 0.84 (95% confidence interval [CI]: 0.76-0.94). Logistic regressions revealed that for the same number of children in the household, participation by undocumented persons was higher than participation by documented persons. Time charts and logistic regressions with interaction terms showed a stronger correspondence between participation in WIC and number of children <6 years old in undocumented households than documented households. Undocumented farm workers' households were only a little less likely to participate in WIC than documented farm workers' households, and undocumented households' participation was especially responsive to the presence of children. These results are consistent with the legal requirements for WIC participation, which do not distinguish between documented and undocumented households. These results may be helpful in the debate surrounding the effects of undocumented workers on WIC participation and costs. PMID:26471950

  10. Bilateral posterior sternoclavicular dislocation.

    PubMed

    Baumann, Matthias; Vogel, Tobias; Weise, Kuno; Muratore, Tim; Trobisch, Per

    2010-07-01

    Posterior sternoclavicular dislocations are a rare injury, representing <5% of all sternoclavicular dislocations and 1 in 1600 shoulder girdle injuries. Proper imaging with computed tomography and prompt diagnosis are essential steps in preventing potentially lethal complications observed in approximately 3% of all posterior sternoclavicular dislocations. Surgical treatment is necessary if closed reduction fails. With the medial clavicular epiphysis being the last to close (between ages 22 and 25), children and adolescents typically present with epiphyseal fractures rather than joint dislocations. If closed reduction fails, open reduction and internal fixation (ORIF) should be considered in fractures, whereas complex reconstructions with tendon graft procedures have been recommended for joint dislocations. This article presents a case of a traumatic bilateral posterior sternoclavicular dislocation due to an epiphyseal fracture in a 15-year-old boy. To our knowledge, this is the first reported case of a bilateral posterior sternoclavicular dislocation. Attempted closed reduction failed with redislocation after 2 days. The patient subsequently required ORIF. This article describes our technique with anterior retraction of the medial clavicle, closure of the posterior periosteum, and ORIF using nonabsorbable sutures. Postoperative shoulder mobilization was started on day 1. At final follow-up, the patient was completely asymptomatic. PMID:20608625

  11. GPU accelerated dislocation dynamics

    NASA Astrophysics Data System (ADS)

    Ferroni, Francesco; Tarleton, Edmund; Fitzgerald, Steven

    2014-09-01

    In this paper we analyze the computational bottlenecks in discrete dislocation dynamics modeling (associated with segment-segment interactions as well as the treatment of free surfaces), discuss the parallelization and optimization strategies, and demonstrate the effectiveness of Graphical Processing Unit (GPU) computation in accelerating dislocation dynamics simulations and expanding their scope. Individual algorithmic benchmark tests as well as an example large simulation of a thin film are presented.

  12. Acute traumatic patellar dislocation.

    PubMed

    Duthon, V B

    2015-02-01

    Inaugural traumatic patellar dislocation is most often due to trauma sustained during physical or sports activity. Two-thirds of acute patellar dislocations occur in young active patients (less than 20 years old). Non-contact knee sprain in flexion and valgus is the leading mechanism in patellar dislocation, accounting for as many as 93% of all cases. The strong displacement of the patella tears the medial stabilizing structures, and notably the medial patellofemoral ligament (MPFL), which is almost always injured in acute patellar dislocation, most frequently at its femoral attachment. Lateral patellar glide can be assessed with the knee in extension or 20° flexion. Displacement by more than 50% of the patellar width is considered abnormal and may induce apprehension. Plain X-ray and CT are mandatory to diagnose bony risk factors for patellar dislocation, such as trochlear dysplasia or increased tibial tubercle-trochlear groove distance (TT-TG), and plan correction. MRI gives information on cartilage and capsulo-ligamentous status for treatment planning: free bodies or osteochondral fracture have to be treated surgically. If patellar dislocation occurs in an anatomically normal knee and osteochondral fracture is ruled out on MRI, non-operative treatment is usually recommended. PMID:25592052

  13. Statistical characterization of dislocation ensembles

    SciTech Connect

    El-Azab, A; Deng, J; Tang, M

    2006-05-17

    We outline a method to study the spatial and orientation statistics of dynamical dislocation systems by modeling the dislocations as a stochastic fiber process. Statistical measures have been introduced for the density, velocity, and flux of dislocations, and the connection between these measures and the dislocation state and plastic distortion rate in the crystal is explained. A dislocation dynamics simulation model has been used to extract numerical data to study the evolution of these statistical measures numerically in a body-centered cubic crystal under deformation. The orientation distribution of the dislocation density, velocity and dislocation flux, as well as the dislocation correlations have been computed. The importance of the statistical measures introduced here in building continuum models of dislocation systems is highlighted.

  14. A Qualitative Study of the Dislocated Working Class

    ERIC Educational Resources Information Center

    Fouad, Nadya A.; Cotter, Elizabeth W.; Carter, Laura; Bernfeld, Steven; Gray, India; Liu, Jane P.

    2012-01-01

    This qualitative study examines factors that influence the career decisions of dislocated workers. The research focuses on individuals identified as working class, as this group has been relatively ignored in past research compared to individuals from higher socioeconomic statuses. Participants include 13 individuals (10 females and 3 males)…

  15. Locked volar distal radioulnar joint dislocation

    PubMed Central

    Bouri, Fadi; Fuad, Mazhar; Elsayed Abdolenour, Ayman

    2016-01-01

    Introduction Volar dislocation of the distal radioulnar joint is a rare injury which is commonly missed in the emergency departments. A thorough review of literature showed very few reported cases and the cause for irreducibility varied in different cases, Lack of suspicion and improper X-ray can delay the diagnosis. Case presentation Our article discusses a case 40 year old construction worker, who presented to the Emergency with work-related injury, complaining of left wrist pain, deformity and inability to rotate his forearm. X-rays revealed a volar dislocation of distal ulna which was reducible after manipulation under General Anesthesia (GA). The joint was stable after the reduction. Discussion Isolated dislocation of the distal radioulnar joint can be either volar or dorsal, although dorsal dislocation is more common. The distal radioulnar articulation plays an important role in the rotational movement of the forearm. It allows pronation and supination which are essential for the function of the upper limb. Pronator Quadratus muscle spasm is an important blockade to reduction and was preventing reduction in this case. Methods The work has been reported in line with the CARE criteria [9]. Conclusion Volar locked dislocation of Distal Radio ulnar joint is a rare injury. High degree of clinical suspicion and proper X-ray is required for prompt detection. The importance of this case is to raise the awareness among physicians in treating these kind of injuries by careful assessment of the patient and radiographs, and to consider pronator quadratus as an important cause for the blockade to reduction. PMID:27016647

  16. Reliability of the Non-Communicating Adult Pain Checklist (NCAPC), Assessed by Different Groups of Health Workers

    ERIC Educational Resources Information Center

    Lotan, M.; Moe-Nilssen, R.; Ljunggren, A. E.; Strand, L. I.

    2009-01-01

    Evaluating pain in adults with intellectual and developmental disability (IDD) is a challenge. The Non-Communicating Adults Pain Checklist (NCAPC) was recently developed from the Non-Communicating Children's Pain Checklist (NCCPC) and examined in a group of adults with IDD (N = 228) and found to hold satisfactory construct validity, internal…

  17. Dislocated Workers. Trade Adjustment Assistance Program Flawed. Statement of Linda G. Morra, Director of Education and Employment Issues, Human Resources Division. Testimony before the Subcommittee on Employment, Housing and Aviation, Committee on Government Operations, House of Representatives.

    ERIC Educational Resources Information Center

    General Accounting Office, Washington, DC. Div. of Human Resources.

    The Trade Adjustment Assistance (TAA) program is designed to help the more than 1 million workers per year who lose their jobs because of permanent layoffs or plant closures, due in part because of imports. Studies show, however, that the TAA program fails to meet the seven goals of a successful reemployment assistance program: (1) TAA benefits…

  18. Dislocation of the hip (image)

    MedlinePlus

    A dislocation is an injury in which a bone is displaced from its proper position. Unless there are accompanying fractures or tissue damage, a simple dislocation may be manipulated back into place. Recovery may ...

  19. Supersonic Dislocation Bursts in Silicon

    DOE PAGESBeta

    Hahn, E. N.; Zhao, S.; Bringa, E. M.; Meyers, M. A.

    2016-06-06

    Dislocations are the primary agents of permanent deformation in crystalline solids. Since the theoretical prediction of supersonic dislocations over half a century ago, there is a dearth of experimental evidence supporting their existence. Here we use non-equilibrium molecular dynamics simulations of shocked silicon to reveal transient supersonic partial dislocation motion at approximately 15 km/s, faster than any previous in-silico observation. Homogeneous dislocation nucleation occurs near the shock front and supersonic dislocation motion lasts just fractions of picoseconds before the dislocations catch the shock front and decelerate back to the elastic wave speed. Applying a modified analytical equation for dislocation evolutionmore » we successfully predict a dislocation density of 1.5 x 10(12) cm(-2) within the shocked volume, in agreement with the present simulations and realistic in regards to prior and on-going recovery experiments in silicon.« less

  20. Supersonic Dislocation Bursts in Silicon.

    PubMed

    Hahn, E N; Zhao, S; Bringa, E M; Meyers, M A

    2016-01-01

    Dislocations are the primary agents of permanent deformation in crystalline solids. Since the theoretical prediction of supersonic dislocations over half a century ago, there is a dearth of experimental evidence supporting their existence. Here we use non-equilibrium molecular dynamics simulations of shocked silicon to reveal transient supersonic partial dislocation motion at approximately 15 km/s, faster than any previous in-silico observation. Homogeneous dislocation nucleation occurs near the shock front and supersonic dislocation motion lasts just fractions of picoseconds before the dislocations catch the shock front and decelerate back to the elastic wave speed. Applying a modified analytical equation for dislocation evolution we successfully predict a dislocation density of 1.5 × 10(12) cm(-2) within the shocked volume, in agreement with the present simulations and realistic in regards to prior and on-going recovery experiments in silicon. PMID:27264746

  1. Supersonic Dislocation Bursts in Silicon

    PubMed Central

    Hahn, E. N.; Zhao, S.; Bringa, E. M.; Meyers, M. A.

    2016-01-01

    Dislocations are the primary agents of permanent deformation in crystalline solids. Since the theoretical prediction of supersonic dislocations over half a century ago, there is a dearth of experimental evidence supporting their existence. Here we use non-equilibrium molecular dynamics simulations of shocked silicon to reveal transient supersonic partial dislocation motion at approximately 15 km/s, faster than any previous in-silico observation. Homogeneous dislocation nucleation occurs near the shock front and supersonic dislocation motion lasts just fractions of picoseconds before the dislocations catch the shock front and decelerate back to the elastic wave speed. Applying a modified analytical equation for dislocation evolution we successfully predict a dislocation density of 1.5 × 1012 cm−2 within the shocked volume, in agreement with the present simulations and realistic in regards to prior and on-going recovery experiments in silicon. PMID:27264746

  2. Supersonic Dislocation Bursts in Silicon

    NASA Astrophysics Data System (ADS)

    Hahn, E. N.; Zhao, S.; Bringa, E. M.; Meyers, M. A.

    2016-06-01

    Dislocations are the primary agents of permanent deformation in crystalline solids. Since the theoretical prediction of supersonic dislocations over half a century ago, there is a dearth of experimental evidence supporting their existence. Here we use non-equilibrium molecular dynamics simulations of shocked silicon to reveal transient supersonic partial dislocation motion at approximately 15 km/s, faster than any previous in-silico observation. Homogeneous dislocation nucleation occurs near the shock front and supersonic dislocation motion lasts just fractions of picoseconds before the dislocations catch the shock front and decelerate back to the elastic wave speed. Applying a modified analytical equation for dislocation evolution we successfully predict a dislocation density of 1.5 × 1012 cm‑2 within the shocked volume, in agreement with the present simulations and realistic in regards to prior and on-going recovery experiments in silicon.

  3. Dislocation dynamics in confined geometry

    NASA Astrophysics Data System (ADS)

    Gómez-García, D.; Devincre, B.; Kubin, L.

    1999-05-01

    A simulation of dislocation dynamics has been used to calculate the critical stress for a threading dislocation moving in a confined geometry. The optimum conditions for conducting simulations in systems of various sizes, down to the nanometer range, are defined. The results are critically compared with the available theoretical and numerical estimates for the problem of dislocation motion in capped layers.

  4. Behavior of dislocations in silicon

    SciTech Connect

    Sumino, Koji

    1995-08-01

    A review is given of dynamic behavior of dislocations in silicon on the basis of works of the author`s group. Topics taken up are generation, motion and multiplication of dislocations as affected by oxygen impurities and immobilization of dislocations due to impurity reaction.

  5. Congenital hip dislocation (image)

    MedlinePlus

    ... by a blow, fall, or other trauma, a dislocation can also occur from birth. The cause is unknown but genetic factors may play a role. Problems resulting from very mild developmental dysplasia of the hip may not become apparent until the person is ...

  6. Antioxidant enzymes status and reproductive health of adult male workers exposed to brick kiln pollutants in Pakistan.

    PubMed

    Jahan, Sarwat; Falah, Samreen; Ullah, Hizb; Ullah, Asad; Rauf, Naveed

    2016-07-01

    The present study was designed to study the effect of brick kilns emissions on the reproductive health and biochemical status of brick kiln workers and people living in the area near brick kilns. Body mass index (BMI) was significantly reduced in brick makers, carriers, and bakers compared to the control. Red blood cells count and hematocrit (%) were significantly high in brick bakers while MCH was significantly reduced in brick makers and brick bakers. Heavy metals (lead, cadmium, and chromium) concentration in whole blood of the brick kiln workers were significantly higher as compared to the control. Antioxidant enzymes (CAT, SOD, POD, GSH, and GR) were significantly reduced in brick kiln workers as compared to the control while TBARS level were significantly high in brick bakers as compared to the control. Plasma leutinizing hormone (LH) was significantly high in brick bakers while testosterone concentrations were significantly reduced in brick makers, carriers, and bakers. The present study shows that brick kiln workers and people living in the brick kiln vicinity are exposed to heavy metals and other pollutants that is a serious threat to their health. Alternate technology is needed to be developed and brick kilns should be replaced. PMID:26996903

  7. 20 CFR 663.165 - How long must an individual be in core services in order to be eligible for intensive services?

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... EMPLOYMENT AND TRAINING ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) ADULT AND DISLOCATED WORKER ACTIVITIES UNDER TITLE I OF THE WORKFORCE INVESTMENT ACT Delivery of Adult and Dislocated Worker...

  8. 20 CFR 663.165 - How long must an individual be in core services in order to be eligible for intensive services?

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... EMPLOYMENT AND TRAINING ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) ADULT AND DISLOCATED WORKER ACTIVITIES UNDER TITLE I OF THE WORKFORCE INVESTMENT ACT Delivery of Adult and Dislocated Worker...

  9. 20 CFR 663.165 - How long must an individual be in core services in order to be eligible for intensive services?

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... EMPLOYMENT AND TRAINING ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) ADULT AND DISLOCATED WORKER ACTIVITIES UNDER TITLE I OF THE WORKFORCE INVESTMENT ACT Delivery of Adult and Dislocated Worker...

  10. Elastodynamic image forces on dislocations

    PubMed Central

    Gurrutxaga-Lerma, Beñat; Balint, Daniel S.; Dini, Daniele; Sutton, Adrian P.

    2015-01-01

    The elastodynamic image forces on edge and screw dislocations in the presence of a planar-free surface are derived. The explicit form of the elastodynamic fields of an injected, quiescent screw dislocation are also derived. The resulting image forces are affected by retardation effects: the dislocations experience no image force for a period of time defined by the arrival and reflection at the free surface of the dislocation fields. For the case of injected, stationary dislocations, it is shown that the elastodynamic image force tends asymptotically to the elastotatic prediction. For the case of injected, moving dislocations, it is shown that the elastodynamic image force on both the edge and the screw dislocations is magnified by inertial effects, and becomes increasingly divergent with time; this additional effect, missing in the elastostatic description, is shown to be substantial even for slow moving dislocations. Finally, it is shown that the elastodynamic image force of an edge dislocation moving towards the surface at the Rayleigh wave speed becomes repulsive, rather than attractive; this is suggestive of instabilities at the core of the dislocation, and likely resonances with the free surface. PMID:26528080

  11. Thermodynamically consistent continuum dislocation dynamics

    NASA Astrophysics Data System (ADS)

    Hochrainer, Thomas

    2016-03-01

    Dislocation based modeling of plasticity is one of the central challenges at the crossover of materials science and continuum mechanics. Developing a continuum theory of dislocations requires the solution of two long standing problems: (i) to represent dislocation kinematics in terms of a reasonable number of variables and (ii) to derive averaged descriptions of the dislocation dynamics (i.e. material laws) in terms of these variables. The kinematic problem (i) was recently solved through the introduction of continuum dislocation dynamics (CDD), which provides kinematically consistent evolution equations of dislocation alignment tensors, presuming a given average dislocation velocity (Hochrainer, T., 2015, Multipole expansion of continuum dislocations dynamics in terms of alignment tensors. Philos. Mag. 95 (12), 1321-1367). In the current paper we demonstrate how a free energy formulation may be used to solve the dynamic closure problem (ii) in CDD. We do so exemplarily for the lowest order CDD variant for curved dislocations in a single slip situation. In this case, a thermodynamically consistent average dislocation velocity is found to comprise five mesoscopic shear stress contributions. For a postulated free energy expression we identify among these stress contributions a back-stress term and a line-tension term, both of which have already been postulated for CDD. A new stress contribution occurs which is missing in earlier CDD models including the statistical continuum theory of straight parallel edge dislocations (Groma, I., Csikor, F.F., Zaiser, M., 2003. Spatial correlations and higher-order gradient terms in a continuum description of dislocation dynamics. Acta Mater. 51, 1271-1281). Furthermore, two entirely new stress contributions arise from the curvature of dislocations.

  12. Design rules for dislocation filters

    SciTech Connect

    Ward, T.; Sánchez, A. M.; Beanland, R.; Tang, M.; Wu, J.; Liu, H.; Dunstan, D. J.

    2014-08-14

    The efficacy of strained layer threading dislocation filter structures in single crystal epitaxial layers is evaluated using numerical modeling for (001) face-centred cubic materials, such as GaAs or Si{sub 1−x}Ge{sub x}, and (0001) hexagonal materials such as GaN. We find that threading dislocation densities decay exponentially as a function of the strain relieved, irrespective of the fraction of threading dislocations that are mobile. Reactions between threading dislocations tend to produce a population that is a balanced mixture of mobile and sessile in (001) cubic materials. In contrast, mobile threading dislocations tend to be lost very rapidly in (0001) GaN, often with little or no reduction in the immobile dislocation density. The capture radius for threading dislocation interactions is estimated to be approximately 40 nm using cross section transmission electron microscopy of dislocation filtering structures in GaAs monolithically grown on Si. We find that the minimum threading dislocation density that can be obtained in any given structure is likely to be limited by kinetic effects to approximately 10{sup 4}–10{sup 5 }cm{sup −2}.

  13. Dislocation dynamics in nanocrystalline nickel.

    PubMed

    Shan, Z W; Wiezorek, J M K; Stach, E A; Follstaedt, D M; Knapp, J A; Mao, S X

    2007-03-01

    It is believed that the dynamics of dislocation processes during the deformation of nanocrystalline materials can only be visualized by computational simulations. Here we demonstrate that observations of dislocation processes during the deformation of nanocrystalline Ni with grain sizes as small as 10 nm can be achieved by using a combination of in situ tensile straining and high-resolution transmission electron microscopy. Trapped unit lattice dislocations are observed in strained grains as small as 5 nm, but subsequent relaxation leads to dislocation recombination. PMID:17359167

  14. Dynamic transitions in dislocation motion

    NASA Astrophysics Data System (ADS)

    Bulatov, Vasily; Cai, Wei; Marian, Jaime

    2003-03-01

    In a series of Molecular Dynamics simulations, we observe that, depending on stress, temperature and line length, screw dislocations in BCC iron move in three strikingly different regimes. Under low stress, the dislocations move smoothly via formation and migration of atomic-sized kinks; although widely believed, such motion mechanism has never been directly observed in full dynamic detail. Then, at a higher stress, dislocation motion suddenly becomes rough: the line becomes rugged and its motion becomes jerky producing in its wake a large amount of debris in the form of lattice vacancies and interstitial clusters. Remarkably, this bizarre behavior is not caused by any external factors, such as dislocation interaction with other crystal defects: the roughening transition is intrinsic to the dislocation itself. Under increasing stress the line raggedness and the amount of debris its motion produces continue to increase until, at some point, another dynamic transition takes place. The dislocation is now seen to cease at once its turbulent motion through the lattice and to initiate a thin plate of sheared crystal, a twin. The twin plate picks up where the dislocation just left off - it extends very fast in the same direction as dislocation motion and increases, gradually, in thickness. Notably, no more debris is produced during the twinning motion. The origin of these dynamic transitions, the underlying atomistic mechanisms of dislocation motion in all three regimes and their implication for strength of shocked materials are discussed.

  15. Multiligamentous injuries and knee dislocations.

    PubMed

    Gimber, Lana H; Scalcione, Luke R; Rowan, Andrew; Hardy, Jolene C; Melville, David M; Taljanovic, Mihra S

    2015-11-01

    Complex capsular ligamentous structures contribute to stability of the knee joint. Simultaneous injury of two or more knee ligaments, aside from concurrent tears involving the anterior cruciate and medial collateral ligaments, is considered to be associated with femorotibial knee dislocations. Proximal tibiofibular joint dislocations are not always easily recognized and may be overlooked or missed. Patellofemoral dislocations can be transient with MR imaging sometimes required to reach the diagnosis. In this article, the authors describe the mechanism of injury, ligamentous disruptions, imaging, and treatment options of various types of knee dislocations including injuries of the femorotibial, proximal tibiofibular, and patellofemoral joints. PMID:26002747

  16. Smectic Edge Dislocations under Shear

    NASA Astrophysics Data System (ADS)

    Chen, Peilong; Lu, Chun-Yi David

    2011-09-01

    Layer structures around an edge dislocation in a smectic phase under shear are studied with both phase field and order parameter models. It is shown that, contrast to a crystal solid, the conventional picture of the Peach--Koehler force experienced by dislocations when the sample is under a shear stress cannot be readily applied to the smectic phases. Under a uniform shear flow, we obtain the phase field and order parameter solutions around an edge dislocation. The solutions elucidate properties such as the layer distortion range around the dislocation and scaling of inter-dislocation interaction on dislocation separation. Calculations on energy dissipation indicate the extreme shear-thinning behavior that an edge dislocation induces a shear stress independent of the shear rate. Finally in a bulk sample with dislocation forming loops and networks, we argue that the uniform flow component around the dislocation is important to the energy dissipation and we show that its scaling exponent with the shear rate is very close to results from many previous rheology measurements.

  17. Atlanto-occipital dislocation

    PubMed Central

    Hall, Graham C; Kinsman, Michael J; Nazar, Ryan G; Hruska, Rob T; Mansfield, Kevin J; Boakye, Maxwell; Rahme, Ralph

    2015-01-01

    Atlanto-occipital dislocation (AOD) is being increasingly recognized as a potentially survivable injury as a result of improved prehospital management of polytrauma patients and increased awareness of this entity, leading to earlier diagnosis and more aggressive treatment. However, despite overall improved outcomes, AOD is still associated with significant morbidity and mortality. The purpose of this paper is to review the biomechanical aspects, clinical features, radiologic criteria, and treatment strategies of AOD. Given that the diagnosis of AOD can be very challenging, a high degree of clinical suspicion is essential to ensure timely recognition and treatment, thus preventing neurological decline or death. PMID:25793163

  18. Total knee arthroplasty in a patient with neglected congenital patellar dislocation.

    PubMed

    Tunay, Servet; Ozkan, Huseyin; Köse, Ozkan; Atik, Aziz; Basbozkurt, Mustafa

    2009-10-01

    Late presentation of congenital patellar dislocation with advanced osteoarthritis is rare. This article presents a case of 56-year-old woman with advanced osteoarthritis due to right neglected congenital patellar dislocation treated with total knee arthroplasty (TKA) with release of the lateral retinaculum and proximal extensor mechanism realignment. One year later, the patient had improvement of her Knee Society scores and painless function, stability, and better extensor strength. A literature search revealed a limited number of similar cases in which congenital patellar dislocation was treated with TKA. Total knee arthroplasty provides a valid treatment option for adults with congenital patellar dislocation who have absence of the femoral sulcus and associated osteoarthritis. Total knee arthroplasty has the ability to correct the pathologies seen with congenital patellar dislocation, eg, external tibial rotation, absence of femoral groove, and patellar hypoplasia. Realignment of extensor mechanism restores quadriceps strength, normal knee biomechanics, and may prevent complications such as dislocation. PMID:19824599

  19. Dislocation Mechanics Under Extreme Pressures

    NASA Astrophysics Data System (ADS)

    Armstrong, Ronald; Arnold, Werner; Zerilli, Frank

    2007-06-01

    The shock-induced plasticity of copper, Armco iron, and tantalum materials is attributed to strain rate control by a substantial dislocation density being generated at the shock front. A thermal activation type constitutive equation is employed for the dislocation generation based on achievement of a limiting small activation volume for the process. A linear dependence of the equivalent compressive stress on logarithm of the plastic strain rate is predicted. The prediction compares favorably with Swegle-Grady and Meyers measurements previously fitted to a power law relationship. For Armco iron and tantalum, control is matched with a dislocation description of deformation twinning at the shock front. By comparison, the uniform shock-less loading in an isentropic compression experiment (ICE) provides for plastic strain rate control by the drag-resisted movement of mobile dislocations within the resident dislocation density.

  20. Perilunate Injuries, Not Dislocated (PLIND)

    PubMed Central

    Herzberg, Guillaume

    2013-01-01

    Purpose We reviewed a series of equivalents of perilunate dislocations and fracture-dislocations (PLDs–PLFDs) in which there was no dislocation of the capitate from the lunate on the initial radiographs. We propose to include these injuries as a variant of perilunate dislocations that we have termed a perilunate injury, not dislocated (PLIND) lesion in a modified classification of perilunate injuries. Methods A review of the records of all acute perilunate injuries and displaced carpal fractures was done in a single-center university hospital wrist surgery unit over a 5-year period. All cases presenting at the acute stage with displaced fractures of scaphoid, lunate, triquetrum, or capitate along with scapholunate and/or lunotriquetral dissociation but no dislocation of the capitate from the lunate in the sagittal or coronal plane were reviewed and considered as PLIND lesions. Results We identified 11 patients with PLIND lesions. Three cases with clinical and radiological follow-up are presented. Discussion Equivalents of PLDs–PLFDs presenting without dislocation of the capitate from the lunate do exist. These injuries may be overlooked despite their severity. They require both osseous and ligamentous repair. Including them into an existing perilunate injuries classification highlights their recognition and enables a better understanding and treatment of both acute and chronic nondislocated perilunate injuries. Level of Evidence Level IV, retrospective case series. PMID:24436839

  1. Bilateral Anterior Shoulder Dislocation with Symmetrical Greater Tuberosity Fracture following Seizure

    PubMed Central

    Suryavanshi, Ashish; Mittal, Amber; Dongre, Snehal; Kashyap, Neeti

    2012-01-01

    Introduction: Majority of bilateral shoulder dislocations are posterior. Simultaneous bilateral anterior shoulder dislocations and bilateral anterior fracture-dislocations are rare and mostly of traumatic origin. We present a rare case of bilateral anterior shoulder dislocation with symmetrical greater tuberosity fracture following an episode of seizure with an unusual injury mechanism which was treated conservatively. Case Report: A 45 year old office worker presented to the Casualty of our hospital with bilateral anterior shoulder dislocations with greater tuberosity fractures following an episode of seizure. Both shoulders were reduced by Kocher manoeuvre using total intravenous anaesthesia (TIVA) & were strapped to the chest for 6 weeks. At the end of 1 year follow-up, there were no reasonable loss of strength or restriction of motion and the shoulders were defined as stable. Conclusion: Although bilateral shoulder dislocations are mostly posterior, bilateral anterior dislocations may not be as rare as previously thought and are frequently missed by the orthopaedic residents in the casualty department. Further to the best of our knowledge, our case represents the first case of bilateral anterior shoulder dislocation with symmetrical greater tuberosity fracture with an unusual mechanism of injury following an episode of seizure in a young male patient that was successfully managed by conservative means.

  2. Patellar Dislocations and Reduction Procedure.

    PubMed

    Ramponi, Denise

    2016-01-01

    Acute patellar dislocations are a common injury occurring in adolescents involved in sports and dancing activities. This injury usually occurs when the knee is in full extension and sustains a valgus stress on the knee. The medial patellofemoral ligament is the medial restraint that assists in stabilizing the patella from lateral dislocations. The patella usually dislocates laterally and is usually not difficult to reduce after patient evaluation and prereduction radiographs. After postreduction radiographs confirm proper position of the patella postreduction and the absence of fractures, the patient is usually treated conservatively with initial immobilization, orthopedic referral, and physical therapy. PMID:27139130

  3. Moving Dislocations in Disordered Alloys.

    SciTech Connect

    Marian, J; Caro, A

    2006-11-18

    Using atomistic simulations of dislocation motion in Ni and Ni-Au alloys we report a detailed study of the mobility function as a function of stress, temperature and alloy composition. We analyze the results in terms of analytic models of phonon radiation and their selection rules for phonon excitation. We find a remarkable agreement between the location of the cusps in the {sigma}-v relation and the velocity of waves propagating in the direction of dislocation motion. We identify and characterize three regimes of dissipation whose boundaries are essentially determined by the direction of motion of the dislocation, rather than by its screw or edge character.

  4. Results of the northern Manhattan diabetes community outreach project: a randomized trial studying a community health worker intervention to improve diabetes care in Hispanic adults.

    PubMed

    Palmas, Walter; Findley, Sally E; Mejia, Miriam; Batista, Milagros; Teresi, Jeanne; Kong, Jian; Silver, Stephanie; Fleck, Elaine M; Luchsinger, Jose A; Carrasquillo, Olveen

    2014-04-01

    OBJECTIVE The Northern Manhattan Diabetes Community Outreach Project evaluated whether a community health worker (CHW) intervention improved clinically relevant markers of diabetes care in adult Hispanics. RESEARCH DESIGN AND METHODS Participants were adult Hispanics, ages 35-70 years, with recent hemoglobin A1c (A1C) ≥8% (≥64 mmol/mol), from a university-affiliated network of primary care practices in northern Manhattan (New York City, NY). They were randomized to a 12-month CHW intervention (n = 181), or enhanced usual care (educational materials mailed at 4-month intervals, preceded by phone calls, n = 179). The primary outcome was A1C at 12 months; the secondary outcomes were systolic blood pressure (SBP), diastolic blood pressure, and LDL-cholesterol levels. RESULTS There was a nonsignificant trend toward improvement in A1C levels in the intervention group (from unadjusted mean A1C of 8.77 to 8.40%), as compared with usual care (from 8.58 to 8.53%) (P = 0.131). There was also a nonsignificant trend toward an increase in SBP and LDL cholesterol in the intervention arm. Intervention fidelity, measured as the number of contacts in the intervention arm (visits, phone contacts, group support, and nutritional education), showed a borderline association with greater A1C reduction (P = 0.054). When assessed separately, phone contacts were associated with greater A1C reduction (P = 0.04). CONCLUSIONS The trend toward A1C reduction with the CHW intervention failed to achieve statistical significance. Greater intervention fidelity may achieve better glycemic control, and more accessible treatment models, such as phone-based interventions, may be more efficacious in socioeconomically disadvantaged populations. PMID:24496805

  5. Dislocation sources in ordered intermetallics

    SciTech Connect

    Yoo, M.H.; Appel, F.; Wagner, R.; Mecking, H.

    1996-09-01

    An overview on the current understanding of dislocation sources and multiplication mechanisms is made for ordered intermetallic alloys of the L1{sub 2}, B2, and D0{sub 19} structures. In L1{sub 2} alloys, a large disparity of edge/screw segments in their relative mobility reduces the efficiency of a Frank-Read Type multiplication mechanism. In Fe-40%Al of the B2 structure, a variety of dislocation sources are available for <111> slip, including ones resulting from condensation of thermal vacancies. In NiAl with the relatively high APB energy, <100> dislocations may result from the dislocation decomposition reactions, the prismatic punching out from inclusion particles, and/or steps and coated layers of the surface. Internal interfaces often provide sites for dislocation multiplication, e.g., grain boundaries, sub-boundaries in Ni{sub 3}Ga, NiAl and Ti{sub 3}Al, and antiphase domain boundaries in Ti{sub 3}Al. As for the crack tip as a dislocation source, extended SISFs trailed by super-Shockley partials emanating form the cracks in Ni{sub 3}Al and Co{sub 3}Ti are discussed in view of a possible toughening mechanism.

  6. Migrant Workers.

    ERIC Educational Resources Information Center

    Social and Labour Bulletin, 1983

    1983-01-01

    Discusses a new German law to encourage foreign workers to return to their home countries, employment exchanges for young foreigners in Germany, and a training program for migrant workers in India. (SK)

  7. A simple model for dislocation emission mediated dynamic nanovoid growth

    NASA Astrophysics Data System (ADS)

    Wilkerson, Justin; Ramesh, K. T.

    2015-06-01

    Failure of ductile metals has long been attributed to the microscopic processes of void nucleation, growth, and finally coalescence leading to fracture. Our traditional view of void nucleation is associated with interface debonding at second-phase particles. However, much of this understanding has been gleaned from observations of quasi-static fracture surfaces. Under more extreme dynamic loading conditions second-phase particles may not necessarily be the dominant source of void nucleating material defects, and a few key experimental observations of laser spall surfaces seem to support this assertion. Here, we motivate an alternative mechanism to the traditional view, namely shock-induced vacancy generation and clustering followed by nanovoid growth mediated by dislocation emission. This mechanism only becomes active at very large stresses, and thus it is desirable to establish a closed-form criterion for the macroscopic stress required to activate dislocation emission in porous materials. Following an approach similar to Lubarda and co-workers, we make use of stability arguments applied to the analytic solutions of the elastic interactions of dislocations and voids to derive the desired criterion. We then propose a dynamic nanovoid growth law that is motivated by the kinetics of dislocation emission. The resulting failure model is validated against a number of molecular dynamics simulations with favorable agreement. Lastly, we make use of our simple model to predict some interesting anomalous behaviors associated with high surface energies and nonlinear elasticity.

  8. Worker Participation

    ERIC Educational Resources Information Center

    Shepherd, W. F.

    1973-01-01

    The philosophy and workability of the concept of worker participation in management decisions is discussed in the context of British society. It is recommended that four interests be represented in any kind of Workers' Council: management, workers, shareholders, and consumers. (AG)

  9. Recurrent posttraumatic trapeziometacarpal joint dislocation in a child: A case report.

    PubMed

    Gaillard, Julien; Fitoussi, Franck

    2016-04-01

    Traumatic trapeziometacarpal joint dislocation of the thumb accounts for less than 1% of all hand injuries. This injury is even less common in children. Optimal treatment strategies for this injury are still the subject of debate for both children and adults. We report a case of recurrent posttraumatic trapeziometacarpal joint dislocation in an eight-year-old girl. We believe our case is the first report of recurrent acute dislocation leading to chronic dislocation in the English medical literature. Restoring the anatomy and biomechanics of the trapeziometacarpal joint is essential when treating these injuries; for this reason, surgical treatment is usually indicated. Overall, the prognosis of trapeziometacarpal dislocation treated acutely is favorable and stable over time. However, the role of open surgery and ligament reconstruction remains controversial, especially in children. PMID:27117129

  10. Dislocations in Monolayers and Semiconductors.

    NASA Astrophysics Data System (ADS)

    Ren, Qiang

    1995-01-01

    Four different aspects of the properties of dislocations in monolayer and semiconductors have been investigated: (i) Using atomic relaxation techniques, dislocation dipoles of various sizes and orientations have been studied for monolayers with the Lennard-Jones potential (LJP) and the nearest-neighbour piecewise linear force (PLF) interactions. In the WP system the lower energy vacancy dipoles have over a wide range of angles an energy which is mainly a function of the vacancy content of the dipole. There is a competition between the elastic forces and the topological constraints which favour a five-fold coordinate vacancy (FCV) at the centre of each core. For the short range PLF system the lattice usually compresses upon the introduction of a dislocation, a consequence of the soft core of the interaction potential, and interstitial dipoles are lower in energy. For the long range LJP system the dislocations are mobile whereas for the PLF system they are pinned. The relevance of these results to existing theories of melting are discussed. (ii) Using generalized stacking-fault (GSF) energies obtained from first-principles density-functional calculations, a zero-temperature model for dislocations in silicon is constructed within the framework of a Peierls-Nabarro (PN) model. Core widths, core energies, PN pinning energies, and stresses are calculated for various possible perfect and imperfect dislocations. Both shuffle and glide sets are considered. 90^circ partials are shown to have a lower Peierls stress (PS) than 30 ^circ partials in accord with experiment. (iii) We have also studied by atomic relaxation techniques the properties of dislocations in silicon, modelled by the empirical potential of Stillinger and Weber. In order to compare with the preceding calculation no reconstruction is allowed. We find no evidence of dissociation in the shuffle dislocations. Within this model shuffle dislocations glide along their slipping planes. On the other hand, glide sets

  11. Elderly Service Workers' Training Project. Final Report.

    ERIC Educational Resources Information Center

    Harvey, Dexter; Cap, Orest

    The Elderly Service Workers' Training Project (ESWTP) was designed to identify the problems encountered by human service workers in their daily contact with older adults. A needs assessment (mail survey and structured personal interview) was conducted throughout Manitoba to identify and document the scope of human service workers' on-the-job…

  12. [Acute acromioclavicular dislocations].

    PubMed

    Riand, N; Sadowski, C; Hoffmeyer, P

    1999-12-01

    Acromioclavicular dislocations represent over 10% of acute traumatic injuries to the shoulder girdle. The mechanism is usually a direct impact on the shoulder with the arm in adduction, producing rupture of the acromioclavicular (AC) ligaments, then of the coracoclavicular (CC) ligament, with displacement of the lateral end of the clavicle. Rockwood described 6 grades of injury. Physical examination usually provides the diagnosis, which is confirmed by radiological examination. X-rays centered on the AC joint, if necessary with forceful adduction of both shoulders or under traction, are useful to evaluate the severity of the lesion. Grade I and II lesions are usually treated conservatively by simply immobilizing the arm for 3 to 4 weeks. Surgical treatment is usually advocated for grade IV, V and VI lesions: AC or CC fixation, sometimes associated with ligament repair, depending on the surgeons. AC pinning or C-C screw fixation are the techniques most often used. Management of grade III lesions remains controversial. Some authors advocate immediate surgical treatment in young, active patients, in heavy laborers and even in slender individuals. The choice of the operative technique is controversial, as no single technique has clearly proved to be superior to others. Other authors advocate conservative treatment, which gives functional results which patients consider quite acceptable, with faster recovery; patients should be informed that results are essentially similar, whatever the treatment. The possibility of performing secondary operations with good results in cases with failure of conservative management is a further argument in favor of applying conservative therapy first in acute injuries. PMID:10675933

  13. Dislocation Multi-junctions and Strain Hardening

    SciTech Connect

    Bulatov, V; Hsiung, L; Tang, M; Arsenlis, A; Bartelt, M; Cai, W; Florando, J; Hiratani, M; Rhee, M; Hommes, G; Pierce, T; Diaz de la Rubia, T

    2006-06-20

    At the microscopic scale, the strength of a crystal derives from the motion, multiplication and interaction of distinctive line defects--dislocations. First theorized in 1934 to explain low magnitudes of crystal strength observed experimentally, the existence of dislocations was confirmed only two decades later. Much of the research in dislocation physics has since focused on dislocation interactions and their role in strain hardening: a common phenomenon in which continued deformation increases a crystal's strength. The existing theory relates strain hardening to pair-wise dislocation reactions in which two intersecting dislocations form junctions tying dislocations together. Here we report that interactions among three dislocations result in the formation of unusual elements of dislocation network topology, termed hereafter multi-junctions. The existence of multi-junctions is first predicted by Dislocation Dynamics (DD) and atomistic simulations and then confirmed by the transmission electron microscopy (TEM) experiments in single crystal molybdenum. In large-scale Dislocation Dynamics simulations, multi-junctions present very strong, nearly indestructible, obstacles to dislocation motion and furnish new sources for dislocation multiplication thereby playing an essential role in the evolution of dislocation microstructure and strength of deforming crystals. Simulation analyses conclude that multi-junctions are responsible for the strong orientation dependence of strain hardening in BCC crystals.

  14. Measurement of probability distributions for internal stresses in dislocated crystals

    SciTech Connect

    Wilkinson, Angus J.; Tarleton, Edmund; Vilalta-Clemente, Arantxa; Collins, David M.; Jiang, Jun; Britton, T. Benjamin

    2014-11-03

    Here, we analyse residual stress distributions obtained from various crystal systems using high resolution electron backscatter diffraction (EBSD) measurements. Histograms showing stress probability distributions exhibit tails extending to very high stress levels. We demonstrate that these extreme stress values are consistent with the functional form that should be expected for dislocated crystals. Analysis initially developed by Groma and co-workers for X-ray line profile analysis and based on the so-called “restricted second moment of the probability distribution” can be used to estimate the total dislocation density. The generality of the results are illustrated by application to three quite different systems, namely, face centred cubic Cu deformed in uniaxial tension, a body centred cubic steel deformed to larger strain by cold rolling, and hexagonal InAlN layers grown on misfitting sapphire and silicon carbide substrates.

  15. Responses to Defense Cutbacks: The Dislocation Aversion Approach. Research and Evaluation Report Series 97-C.

    ERIC Educational Resources Information Center

    Social Policy Research Associates, Menlo Park, CA.

    Of the 19 projects conducted as part of the Defense Conversion Adjustment (DCA) Demonstration administered by the U.S. Department of Labor's Office of Work-Based Learning, 9 tested the dislocation aversion approach. The projects attempted to alleviate the negative impacts of defense cutbacks on communities, firms, and workers. Six projects…

  16. Rural Dislocated Women in Career Transition: The Importance of Supports and Strategies

    ERIC Educational Resources Information Center

    McAtee, Atticia B.; Benshoff, James M.

    2006-01-01

    Job loss researchers have focused on the physical and mental well being of White working and middle class men, their families, friends, and coworkers to with immediate reemployment as the outcome. This study focused on low-income rural women dislocated workers and their decision to enroll in community college for retraining or seek immediate…

  17. Dislocations and other topological oddities

    NASA Astrophysics Data System (ADS)

    Pieranski, Pawel

    2016-03-01

    We will show that the book Dislocations by Jacques Friedel, published half a century ago, can still be recommended, in agreement with the author's intention, as a textbook "for research students at University and for students at engineering schools as well as for research engineers". Indeed, today dislocations are known to occur not only in solid crystals but also in many other systems discovered more recently such as colloidal crystals or liquid crystals having periodic structures. Moreover, the concept of dislocations is an excellent starting point for lectures on topological defects occurring in systems equipped with order parameters resulting from broken symmetries: disclinations in nematic or hexatic liquid crystals, dispirations in chiral smectics or disorientations in lyotropic liquid crystals. The discussion of dislocations in Blue Phases will give us an opportunity to call on mind Sir Charles Frank, friend of Jacques Friedel since his Bristol years, who called these ephemeral mesophases "topological oddities". Being made of networks of disclinations, Blue Phases are similar to Twist Grain Boundary (TGB) smectic phases, which are made of networks of screw dislocations and whose existence was predicted by de Gennes in 1972 on the basis of the analogy between smectics and superconductors. We will stress that the book by Jacques Friedel contains seeds of this analogy.

  18. Education and Today's Older Worker.

    ERIC Educational Resources Information Center

    Roberson, Donald N.

    New perspectives need to be gained on the roles of older adults and older workers in the new millenium. Because today's adult is healthier, policies concerning social security, retirement, and work need to be changed. There is a need for acceptance of various types of aging. Rather than mandating specific retirement, the individual should have…

  19. Multiscale Theory of Dislocation Climb

    NASA Astrophysics Data System (ADS)

    Geslin, Pierre-Antoine; Appolaire, Benoît; Finel, Alphonse

    2015-12-01

    Dislocation climb is a ubiquitous mechanism playing a major role in the plastic deformation of crystals at high temperature. We propose a multiscale approach to model quantitatively this mechanism at mesoscopic length and time scales. First, we analyze climb at a nanoscopic scale and derive an analytical expression of the climb rate of a jogged dislocation. Next, we deduce from this expression the activation energy of the process, bringing valuable insights to experimental studies. Finally, we show how to rigorously upscale the climb rate to a mesoscopic phase-field model of dislocation climb. This upscaling procedure opens the way to large scale simulations where climb processes are quantitatively reproduced even though the mesoscopic length scale of the simulation is orders of magnitude larger than the atomic one.

  20. Multiscale Theory of Dislocation Climb.

    PubMed

    Geslin, Pierre-Antoine; Appolaire, Benoît; Finel, Alphonse

    2015-12-31

    Dislocation climb is a ubiquitous mechanism playing a major role in the plastic deformation of crystals at high temperature. We propose a multiscale approach to model quantitatively this mechanism at mesoscopic length and time scales. First, we analyze climb at a nanoscopic scale and derive an analytical expression of the climb rate of a jogged dislocation. Next, we deduce from this expression the activation energy of the process, bringing valuable insights to experimental studies. Finally, we show how to rigorously upscale the climb rate to a mesoscopic phase-field model of dislocation climb. This upscaling procedure opens the way to large scale simulations where climb processes are quantitatively reproduced even though the mesoscopic length scale of the simulation is orders of magnitude larger than the atomic one. PMID:26765003

  1. [Traumatic hip dislocation in childhood].

    PubMed

    Stachel, P; Hofmann-v Kap-herr, S; Schild, H

    1989-06-01

    The article reports on eight cases of traumatic dislocation of the hip in children. Six of these were genuine dislocations and two dislocation fractures. The children were between 5 and 13 years of age at the time of injury. Seven of these 8 children could be followed up one to 21 years after the accident. All 7 children were free from complaints at the time of follow-up examination; in one case only we found a moderate loss of function in the injured hip joint. In this patient the x-ray film showed deformation of the head of the femur after partial necrosis of the femoral head, as well as initial signs of coxarthrosis. Prognosis of this rare injury in children is favourable if repositioning is performed in time and if relief of the hip is effected for the proper period of time, depending on the individual case. PMID:2665382

  2. Sideline Management of Joint Dislocations.

    PubMed

    Schupp, Christian M; Rand, Scott E; Hanson, Travis W; Lee, Bryan M; Jafarnia, Korsh; Jia, Yuhang; Moseley, J Bruce; Seaberg, John P; Seelhoefer, Gregory M

    2016-01-01

    Athletes can sustain a large variety of injuries from simple soft tissue sprains to complex fractures and joint dislocations. This article reviews and provides the most recent information for sports medicine professionals on the management of simple and complex joint dislocations, i.e., irreducible and/or associated with a fracture, from the sidelines without the benefit of imaging. For each joint, the relevant anatomy, common mechanisms, sideline assessment, reduction techniques, initial treatment, and potential complications will be discussed, which allow for the safe and prompt return of athletes to the field of play. PMID:27172077

  3. Bipolar dislocation of the clavicle.

    PubMed

    Jiang, Wei; Gao, Shu-Guang; Li, Yu-Sheng; Lei, Guang-Hua

    2012-11-01

    Bipolar dislocation of the clavicle at acromioclavicular and sternoclavicular joint is an uncommon traumatic injury. The conservative treatments adopted in the past is associated with redislocation dysfunction and deformity. A 41 years old lady with bipolar dislocation of right shoulder is treated surgically by open reduction and internal fixation by oblique T-plate at sternoclavicular joint and Kirschner wire stabilization at acromioclavicular joint. The patient showed satisfactory recovery with full range of motion of the right shoulder and normal muscular strength. The case reported in view of rarity and at 2 years followup. PMID:23325981

  4. Drift of dislocation tripoles under ultrasound influence.

    PubMed

    Murzaev, R T; Bachurin, D V; Nazarov, A A

    2016-01-01

    Numerical simulations of dynamics of different stable dislocation tripoles under influence of monochromatic standing sound wave were performed. The basic conditions necessary for the drift and mutual rearrangements between dislocation structures were investigated. The dependence of the drift velocity of the dislocation tripoles as a function of the frequency and amplitude of the external influence was obtained. The results of the work can be useful in analysis of motion and self-organization of dislocation structure under ultrasound influence. PMID:26278625

  5. Light scattering from dislocations in silicon

    NASA Astrophysics Data System (ADS)

    Monier, Vanessa; Capello, Luciana; Kononchuk, Oleg; Pichaud, Bernard

    2010-11-01

    Nondecorated glide dislocations in Czochralski grown silicon have been studied by laser scattering tomography technique. Dependence of intensity of scattered light on polarization of the incident light has been measured for different orientations of the dislocation line and Burgers vector. Detailed theory of light scattering by dislocation in silicon crystals is presented. It is shown that by combination of polarization and tomography measurements it is possible to determine slip system of nondecorated mixed dislocation in Si.

  6. 14 CFR 314.6 - Qualifying dislocation.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 4 2010-01-01 2010-01-01 false Qualifying dislocation. 314.6 Section 314.6 Aeronautics and Space OFFICE OF THE SECRETARY, DEPARTMENT OF TRANSPORTATION (AVIATION PROCEEDINGS) PROCEDURAL REGULATIONS EMPLOYEE PROTECTION PROGRAM General § 314.6 Qualifying dislocation. A qualifying dislocation is...

  7. Evaluation of Worker Profiling and Reemployment Services Systems: Interim Report. Unemployment Insurance Occasional Paper 96-1.

    ERIC Educational Resources Information Center

    Hawkins, Evelyn K.; And Others

    The Evaluation of Worker Profiling and Reemployment Services (WPRS) systems was designed to provide the U.S. Department of Labor information on how states are designing, implementing, and operating their worker profiling and reemployment services systems for dislocated workers and to compare the effectiveness of different state approaches to…

  8. Interaction of <1 0 0> dislocation loops with dislocations studied by dislocation dynamics in α-iron

    NASA Astrophysics Data System (ADS)

    Shi, X. J.; Dupuy, L.; Devincre, B.; Terentyev, D.; Vincent, L.

    2015-05-01

    Interstitial dislocation loops with Burgers vector of <1 0 0> type are formed in α-iron under neutron or heavy ion irradiation. As the density and size of these loops increase with radiation dose and temperature, these defects are thought to play a key role in hardening and subsequent embrittlement of iron-based steels. The aim of the present work is to study the pinning strength of the loops on mobile dislocations. Prior to run massive Dislocation Dynamics (DD) simulations involving experimentally representative array of radiation defects and dislocations, the DD code and its parameterization are validated by comparing the individual loop-dislocation reactions with those obtained from direct atomistic Molecular Dynamics (MD) simulations. Several loop-dislocation reaction mechanisms are successfully reproduced as well as the values of the unpinning stress to detach mobile dislocations from the defects.

  9. Solute drag on perfect and extended dislocations

    NASA Astrophysics Data System (ADS)

    Sills, R. B.; Cai, W.

    2016-04-01

    The drag force exerted on a moving dislocation by a field of mobile solutes is studied in the steady state. The drag force is numerically calculated as a function of the dislocation velocity for both perfect and extended dislocations. The sensitivity of the non-dimensionalized force-velocity curve to the various controlling parameters is assessed, and an approximate analytical force-velocity expression is given. A non-dimensional parameter S characterizing the strength of the solute-dislocation interaction, the background solute fraction ?, and the dislocation character angle ?, are found to have the strongest influence on the force-velocity curve. Within the model considered here, a perfect screw dislocation experiences no solute drag, but an extended screw dislocation experiences a non-zero drag force that is about 10 to 30% of the drag on an extended edge dislocation. The solutes can change the spacing between the Shockley partials in both stationary and moving extended dislocations, even when the stacking fault energy remains unaltered. Under certain conditions, the solutes destabilize an extended dislocation by either collapsing it into a perfect dislocation or causing the partials to separate unboundedly. It is proposed that the latter instability may lead to the formation of large faulted areas and deformation twins in low stacking fault energy materials containing solutes, consistent with experimental observations of copper and stainless steel containing hydrogen.

  10. Discrete dislocation dynamics simulations in a cylinder

    NASA Astrophysics Data System (ADS)

    Li, Maosheng; Gao, Chan; Xu, Jianing

    2015-02-01

    Mechanical properties of material are closely related to the motion of dislocations, and predicting the interactions and resulting collective motion of dislocations is a major task in understanding and modelling plastically deforming materials. A discrete dislocation dynamics model is used to describe the orientation substructure within the microstructure. Discrete dislocation dynamics simulations in three dimensions have been used to examine the role of dislocation multiplication and mobility on the plasticity in small samples under uniaxial compression. In this paper we describe the application of the dislocation dynamics simulations in a cylindrical geometry. The boundary conditions for the simulation were estimated from the distribution of the geometrically necessary dislocation density which was obtained from the orientation map. Numerical studies benchmark could validate the accuracy of the algorithms and the importance of handling the singularity correctly. The results of the simulation explain the formation of the experimentally observed substructure.

  11. Dislocation boundaries and active slip systems

    SciTech Connect

    Wert, J.A.; Hansen, N.

    1995-11-01

    Part of the dislocations which have participated in the plastic deformation of a polycrystalline metal are stored in dislocation boundaries in a two- or three-dimensional arrangement. The dislocation in such boundaries can be analyzed by determining the misorientation between neighboring crystallites and the boundary orientation. Information about the dislocations in the boundaries can also be obtained by an analysis of active slip systems based on the crystallite orientation and the imposed stress or strain state in combination with appropriate constraint conditions. In the present paper an analysis of the boundary dislocation structure and of the slip systems has been conducted for pure aluminium cold-rolled to a von Mises strain of 0.41. The results show that a substantial majority of dislocations in different types of dislocation boundaries are from the primary and conjugate slip system in the adjoining crystallites. A basis is therefore provided for integrating deformation structure observations with plastic deformation behavior.

  12. Theory of interacting dislocations on cylinders

    NASA Astrophysics Data System (ADS)

    Amir, Ariel; Paulose, Jayson; Nelson, David R.

    2013-04-01

    We study the mechanics and statistical physics of dislocations interacting on cylinders, motivated by the elongation of rod-shaped bacterial cell walls and cylindrical assemblies of colloidal particles subject to external stresses. The interaction energy and forces between dislocations are solved analytically, and analyzed asymptotically. The results of continuum elastic theory agree well with numerical simulations on finite lattices even for relatively small systems. Isolated dislocations on a cylinder act like grain boundaries. With colloidal crystals in mind, we show that saddle points are created by a Peach-Koehler force on the dislocations in the circumferential direction, causing dislocation pairs to unbind. The thermal nucleation rate of dislocation unbinding is calculated, for an arbitrary mobility tensor and external stress, including the case of a twist-induced Peach-Koehler force along the cylinder axis. Surprisingly rich phenomena arise for dislocations on cylinders, despite their vanishing Gaussian curvature.

  13. Community Adult Education; Evidence Submitted to the Russell Committee on Adult Education in England and Wales by the Workers' Educational Association (West Lancashire & Cheshire District) and the Liverpool Educational Priority Area Action/Research Project.

    ERIC Educational Resources Information Center

    Lovett, T. O.

    This paper discusses six roles which an adult education agency can fill in an Educational Priority Area and illustrates each one with examples from the Liverpool E.P.A. Project. These roles are: (1) adult education cum community development; (2) adult education as a resource in community development work; (3) adult education as an aid to parents…

  14. Epidemiology of traumatic hip dislocation in patients treated in Ceará, Brazil

    PubMed Central

    Lima, Luciana Cascão; do Nascimento, Robson Alves; de Almeida, Victor Monte Tenório; Façanha, Fernando Antônio Mendes

    2014-01-01

    OBJECTIVE: To describe the epidemiological profile of patients with traumatic hip dislocation treated in our Institute from November/2012 to July/2013. METHODS: A descriptive cross-sectional study based on interviews and involving 43 patients who suffered traumatic hip dislocation was conducted. RESULTS: The mean age of patients was 34.4 years old and 90.7% were male. Regarding the mechanism of injury, 95% involved traffic accidents. The posterior dislocation of the hip was the most common injury (93%). Associated lesions were observed in 74.4% of patients, hip fractures being the most frequent. The time span between accident and dislocation reduction was less than 6 hours in 37.2% of patients, between 6 and 12 hours in 32.5% and over 12 hours in 30.3%, ranging from 1 hour to 15 days. A fraction of 90.7% of patients was submitted to closed reduction. CONCLUSION: Traumatic hip dislocation affected mostly young adults, victims of traffic accidents. The posterior dislocation of the hip was the most frequent injury and closed reduction was performed in 90.7% of patients. The time span between accident and dislocation reduction was less than 12 hours in most patients. Level of Evidence III, Study of Nonconsecutive Patients. PMID:25061422

  15. Simultaneous shoulder and elbow dislocation

    PubMed Central

    Çobanoğlu, Mutlu; Yumrukcal, Feridun; Karataş, Cengiz; Duygun, Fatih

    2014-01-01

    Ipsilateral shoulder and elbow dislocation is very rare and only six articles are present in the literature mentioning this kind of a complex injury. With this presentation we aim to emphasise the importance of assessing the adjacent joints in patients with trauma in order not to miss any accompanying pathologies. We report a case of a 43-year-old female patient with ipsilateral right shoulder and elbow dislocation treated conservatively. The patient reported elbow pain when first admitted to emergency service but she was diagnosed with simultaneous ipsilateral shoulder and elbow injury and treated conservatively. As a more painful pathology may mask the additional ones, one should hasten to help before performing a complete evaluation. Any harm caused to the patient due to this reason would not be a complication but a malpractice. PMID:24859563

  16. Dislocation creep of dry quartz

    NASA Astrophysics Data System (ADS)

    Kilian, Rüdiger; Heilbronner, Renée.; Holyoke, Caleb W.; Kronenberg, Andreas K.; Stünitz, Holger

    2016-05-01

    Small-scale shear zones within the Permian Truzzo meta-granite developed during the Alpine orogeny at amphibolite facies conditions. In these shear zones magmatic quartz deformed by dislocation creep and recrystallized dynamically by grain boundary migration with minor subgrain rotation recrystallization to a grain size of around 250-750 µm, consistent with flow at low differential stresses. Fourier transform infrared (FTIR) spectroscopy reveals very low water contents in the interior of recrystallized grains (in the form of discrete OH peaks, ~20 H/106Si and very little broad band absorption, <100 H/106Si). The spectral characteristics are comparable to those of dry Brazil quartz. In FTIR spectra, magmatic quartz grains show a broad absorption band related with high water concentrations only in those areas where fluid inclusions are present while other areas are dry. Drainage of fluid inclusions and synkinematic growth of hydrous minerals indicates that a hydrous fluid has been available during deformation. Loss of intragranular water during grain boundary migration recrystallization did not result in a microstructure indicative of hardening. These FTIR measurements provide the first evidence that quartz with extremely low intragranular water contents can deform in nature by dislocation creep at low differential stresses. Low intragranular water contents in naturally deformed quartz may not be necessarily indicative of a high strength, and the results are contrary to implications taken from deformation experiments where very high water contents are required to allow dislocation creep in quartz. It is suggested that dislocation creep of quartz in the Truzzo meta-granite is possible to occur at low differential stresses because sufficient amounts of intergranular water ensure a high recovery rate by grain boundary migration while the absence of significant amounts of intragranular water is not crucial at natural conditions.

  17. Misfit dislocation nucleation in heteroepitaxy

    NASA Astrophysics Data System (ADS)

    Trushin, Oleg; Ying, See Chen; Granato, Enzo; Ala-Nissila, Tapio

    2001-03-01

    We have studied atomic mechanisms of misfit dislocation nucleation in heteroepitaxy with semiempirical potentials. Many-body mechanisms of stress relaxation are systematically investigated with Lennard-Jones potential in 2D and 3D cases. Energy barriers for dislocation nucleation are estimated using modern methods for saddle point search (Nudged Elastic Band [1], Eigenvector Following [2] and others). Moreover, new simple and effective method for transition paths searching is proposed. Based on the data the critical thickness of film is estimated as a function of film-substrate lattice misfit. Moreover, to make the study more realistic we used EAM [3] potentials in simulations of Pd/Cu and Cu/Pd systems. We show that the dislocations nucleate more easily in compressive than tensile strained films, and in fcc(111) orientation rather than in fcc(100). These findings are in agreement with recent experimental and theoretical works. 1. H. Jonsson, G. Mills and K. W. Jacobsen, in Classical and Quantum Dynamics in Condensed Phase Simulations, ed. by B. J. Berne, G. Ciccotti, and D. F. Coker (World Scientific, Singapore, 1998). 2. L. J. Munro and D. J. Wales, Phys. Rev. B v59, 3969 (1999), and references therein. 3. S. M. Foiles, M. I. Baskes, and M. S. Daw, Phys. Rev. B v33, 7983 (1986).

  18. Visualization of dislocation dynamics in colloidal crystals.

    PubMed

    Schall, Peter; Cohen, Itai; Weitz, David A; Spaepen, Frans

    2004-09-24

    The dominant mechanism for creating large irreversible strain in atomic crystals is the motion of dislocations, a class of line defects in the crystalline lattice. Here we show that the motion of dislocations can also be observed in strained colloidal crystals, allowing detailed investigation of their topology and propagation. We describe a laser diffraction microscopy setup used to study the growth and structure of misfit dislocations in colloidal crystalline films. Complementary microscopic information at the single-particle level is obtained with a laser scanning confocal microscope. The combination of these two techniques enables us to study dislocations over a range of length scales, allowing us to determine important parameters of misfit dislocations such as critical film thickness, dislocation density, Burgers vector, and lattice resistance to dislocation motion. We identify the observed dislocations as Shockley partials that bound stacking faults of vanishing energy. Remarkably, we find that even on the scale of a few lattice vectors, the dislocation behavior is well described by the continuum approach commonly used to describe dislocations in atomic crystals. PMID:15448265

  19. Three-dimensional formulation of dislocation climb

    NASA Astrophysics Data System (ADS)

    Gu, Yejun; Xiang, Yang; Quek, Siu Sin; Srolovitz, David J.

    2015-10-01

    We derive a Green's function formulation for the climb of curved dislocations and multiple dislocations in three-dimensions. In this new dislocation climb formulation, the dislocation climb velocity is determined from the Peach-Koehler force on dislocations through vacancy diffusion in a non-local manner. The long-range contribution to the dislocation climb velocity is associated with vacancy diffusion rather than from the climb component of the well-known, long-range elastic effects captured in the Peach-Koehler force. Both long-range effects are important in determining the climb velocity of dislocations. Analytical and numerical examples show that the widely used local climb formula, based on straight infinite dislocations, is not generally applicable, except for a small set of special cases. We also present a numerical discretization method of this Green's function formulation appropriate for implementation in discrete dislocation dynamics (DDD) simulations. In DDD implementations, the long-range Peach-Koehler force is calculated as is commonly done, then a linear system is solved for the climb velocity using these forces. This is also done within the same order of computational cost as existing discrete dislocation dynamics methods.

  20. Responses to Defense Cutbacks: The Worker Mobility Approach. Research and Evaluation Report Series 97-D.

    ERIC Educational Resources Information Center

    Social Policy Research Associates, Menlo Park, CA.

    Of the 19 projects conducted as part of the Defense Conversion Adjustment (DCA) Demonstration administered by the U.S. Department of Labor's Office of Work-Based Learning, 8 tested the worker mobility approach. The projects, which shared the common goal of helping dislocated defense workers find high-quality jobs, tested one or more of the…

  1. "I'm Not a Quitter!" Job Training and Basic Education for Women Textile Workers.

    ERIC Educational Resources Information Center

    Merrifield, Juliet; And Others

    A case study was done on the effects of training programs sponsored by the Job Training Partnership Act (JTPA) on 835 women textile workers dislocated by a plant closing in Blount County, Tennessee. Data were gathered by former workers through structured interviews with 100 women typical by age (about 45-years-old) and length of service (14-16…

  2. TELEVISION AND SOCIAL WORK, A CASE HISTORY OF A PROJECT IN ADULT EDUCATION, BASED ON THE BBC-2 TELEVISION SERIES, 'THE SOCIAL WORKERS,' OCTOBER 1965-FEBRUARY 1966.

    ERIC Educational Resources Information Center

    HANDCOCK, ALAN; ROBINSON, JOHN

    A COMBINATION OF TELEVISION, GROUP STUDY, PRIVATE STUDY, CORRESPONDENCE STUDY, AND PRACTICAL WORK PROVIDED AN EXTENSIVE INTRODUCTION TO THE NATURE AND METHODS OF SOCIAL WORK, PRINCIPALLY FOR VOLUNTEER AND PART-TIME WORKERS THROUGH 16 HALF-HOUR PROGRAMS ON SOCIAL WORK AND ADMINISTRATION BROADCAST ON BBC-2 BETWEEN OCTOBER 5, 1965 AND FEBRUARY 8,…

  3. Location, location, location: larvae position inside the nest is correlated with adult body size in worker bumble-bees (Bombus impatiens).

    PubMed

    Couvillon, Margaret J; Dornhaus, Anna

    2009-07-01

    Social insects display task-related division of labour. In some species, division of labour is related to differences in body size, and worker caste members display morphological adaptations suited for particular tasks. Bumble-bee workers (Bombus spp.) can vary in mass by eight- to tenfold within a single colony, which previous work has linked to division of labour. However, little is known about the proximate mechanism behind the production of this wide range of size variation within the worker caste. Here, we quantify the larval feeding in Bombus impatiens in different nest zones of increasing distance from the centre. There was a significant difference in the number of feedings per larva across zones, with a significant decrease in feeding rates as one moved outwards from the centre of the nest. Likewise, the diameter of the pupae in the peripheral zones was significantly smaller than that of pupae in the centre. Therefore, we conclude that the differential feeding of larvae within a nest, which leads to the size variation within the worker caste, is based on the location of brood clumps. Our work is consistent with the hypothesis that some larvae are 'forgotten', providing a possible first mechanism for the creation of size polymorphism in B. impatiens. PMID:19364744

  4. Location, location, location: larvae position inside the nest is correlated with adult body size in worker bumble-bees (Bombus impatiens)

    PubMed Central

    Couvillon, Margaret J.; Dornhaus, Anna

    2009-01-01

    Social insects display task-related division of labour. In some species, division of labour is related to differences in body size, and worker caste members display morphological adaptations suited for particular tasks. Bumble-bee workers (Bombus spp.) can vary in mass by eight- to tenfold within a single colony, which previous work has linked to division of labour. However, little is known about the proximate mechanism behind the production of this wide range of size variation within the worker caste. Here, we quantify the larval feeding in Bombus impatiens in different nest zones of increasing distance from the centre. There was a significant difference in the number of feedings per larva across zones, with a significant decrease in feeding rates as one moved outwards from the centre of the nest. Likewise, the diameter of the pupae in the peripheral zones was significantly smaller than that of pupae in the centre. Therefore, we conclude that the differential feeding of larvae within a nest, which leads to the size variation within the worker caste, is based on the location of brood clumps. Our work is consistent with the hypothesis that some larvae are ‘forgotten’, providing a possible first mechanism for the creation of size polymorphism in B. impatiens. PMID:19364744

  5. Kinetics of a Fast Moving Partial Dislocation

    NASA Astrophysics Data System (ADS)

    Daphalapurkar, Nitin; Ramesh, K. T.

    2013-03-01

    Plastic deformation in materials under extreme stresses requires a kinetic description of moving dislocations. The velocities with which the partial dislocations can propagate under an applied stress has implications for plasticity at high strain rates, specifically, the rate of plastic deformation and the rate-sensitivity. In this work, we focus our attention on motion of a twinning partial dislocation in a face-centered cubic (FCC) material, Ni. We use molecular dynamics simulations to simulate the velocity of a propagating twinning partial dislocation and investigate the effect of applied shear stress. Results suggest a limiting value for the speeds of a propagating partial dislocation. The material speeds based on the nonlinear part (under high stresses) of the stress-strain curve are shown to have an influence on the velocity with which a partial dislocation can propagate. Predicted velocities from simulations will be related to observations from high rate impact experiments. Supported by Hopkins Extreme Materials Institute

  6. Coupled dislocation and martensitic phase transformation dynamics

    NASA Astrophysics Data System (ADS)

    Barros, Kipton; Acharya, Amit; Lookman, Turab

    2013-03-01

    We present a field theoretic model that couples dislocation dynamics and plasticity with martensitic phase transformation. Dislocations produce long-range stress via incompatibility of the elastic-distortion field. Phase transformations are modeled with a non-convex elastic potential that contains the crystal symmetries of austenite and martensite phases. We discuss the effects of dislocation dynamics on material microstructure produced under extreme conditions.

  7. Living "a Life like Ours": Support Workers' Accounts of Substitute Decision-Making in Residential Care Homes for Adults with Intellectual Disabilities

    ERIC Educational Resources Information Center

    Dunn, M. C.; Clare, I. C. H.; Holland, A. J.

    2010-01-01

    Background: In England and Wales, the "Mental Capacity Act 2005" (MCA) provides a new legal framework to regulate substitute decision-making relating to the welfare of adults who lack the capacity to make one or more autonomous decisions about their care and support. Any substitute decision made on behalf of an adult lacking capacity must be in…

  8. Robust atomistic calculation of dislocation line tension

    NASA Astrophysics Data System (ADS)

    Szajewski, B. A.; Pavia, F.; Curtin, W. A.

    2015-12-01

    The line tension Γ of a dislocation is an important and fundamental property ubiquitous to continuum scale models of metal plasticity. However, the precise value of Γ in a given material has proven difficult to assess, with literature values encompassing a wide range. Here results from a multiscale simulation and robust analysis of the dislocation line tension, for dislocation bow-out between pinning points, are presented for two widely-used interatomic potentials for Al. A central part of the analysis involves an effective Peierls stress applicable to curved dislocation structures that markedly differs from that of perfectly straight dislocations but is required to describe the bow-out both in loading and unloading. The line tensions for the two interatomic potentials are similar and provide robust numerical values for Al. Most importantly, the atomic results show notable differences with singular anisotropic elastic dislocation theory in that (i) the coefficient of the \\text{ln}(L) scaling with dislocation length L differs and (ii) the ratio of screw to edge line tension is smaller than predicted by anisotropic elasticity. These differences are attributed to local dislocation core interactions that remain beyond the scope of elasticity theory. The many differing literature values for Γ are attributed to various approximations and inaccuracies in previous approaches. The results here indicate that continuum line dislocation models, based on elasticity theory and various core-cut-off assumptions, may be fundamentally unable to reproduce full atomistic results, thus hampering the detailed predictive ability of such continuum models.

  9. Dislocation-driven surface dynamics on solids.

    PubMed

    Kodambaka, S; Khare, S V; Swiech, W; Ohmori, K; Petrov, I; Greene, J E

    2004-05-01

    Dislocations are line defects that bound plastically deformed regions in crystalline solids. Dislocations terminating on the surface of materials can strongly influence nanostructural and interfacial stability, mechanical properties, chemical reactions, transport phenomena, and other surface processes. While most theoretical and experimental studies have focused on dislocation motion in bulk solids under applied stress and step formation due to dislocations at surfaces during crystal growth, very little is known about the effects of dislocations on surface dynamics and morphological evolution. Here we investigate the near-equilibrium dynamics of surface-terminated dislocations using low-energy electron microscopy. We observe, in real time, the thermally driven nucleation and shape-preserving growth of spiral steps rotating at constant temperature-dependent angular velocities around cores of dislocations terminating on the (111) surface of TiN in the absence of applied external stress or net mass change. We attribute this phenomenon to point-defect migration from the bulk to the surface along dislocation lines. Our results demonstrate that dislocation-mediated surface roughening can occur even in the absence of deposition or evaporation, and provide fundamental insights into mechanisms controlling nanostructural stability. PMID:15129275

  10. Arthroscopic Treatment of Traumatic Hip Dislocation.

    PubMed

    Begly, John P; Robins, Bryan; Youm, Thomas

    2016-05-01

    Traumatic hip dislocations are high-energy injuries that often result in considerable morbidity. Although appropriate management improves outcomes, associated hip pathology may complicate the recovery and lead to future disability and pain. Historically, open reduction has been the standard of care for treating hip dislocations that require surgical intervention. The use of hip arthroscopy to treat the sequelae and symptoms resulting from traumatic hip dislocations recently has increased, however. When used appropriately, hip arthroscopy is a safe, effective, and minimally invasive treatment option for intra-articular pathology secondary to traumatic hip dislocation. PMID:27007728

  11. Multiscale modeling of dislocation-precipitate interactions in Fe: From molecular dynamics to discrete dislocations

    NASA Astrophysics Data System (ADS)

    Lehtinen, Arttu; Granberg, Fredric; Laurson, Lasse; Nordlund, Kai; Alava, Mikko J.

    2016-01-01

    The stress-driven motion of dislocations in crystalline solids, and thus the ensuing plastic deformation process, is greatly influenced by the presence or absence of various pointlike defects such as precipitates or solute atoms. These defects act as obstacles for dislocation motion and hence affect the mechanical properties of the material. Here we combine molecular dynamics studies with three-dimensional discrete dislocation dynamics simulations in order to model the interaction between different kinds of precipitates and a 1/2 <111 > {110 } edge dislocation in BCC iron. We have implemented immobile spherical precipitates into the ParaDis discrete dislocation dynamics code, with the dislocations interacting with the precipitates via a Gaussian potential, generating a normal force acting on the dislocation segments. The parameters used in the discrete dislocation dynamics simulations for the precipitate potential, the dislocation mobility, shear modulus, and dislocation core energy are obtained from molecular dynamics simulations. We compare the critical stresses needed to unpin the dislocation from the precipitate in molecular dynamics and discrete dislocation dynamics simulations in order to fit the two methods together and discuss the variety of the relevant pinning and depinning mechanisms.

  12. Elbow Dislocations: A Review Ranging from Soft Tissue Injuries to Complex Elbow Fracture Dislocations

    PubMed Central

    Zellner, Johannes; Koller, Michael; Nerlich, Michael; Lenich, Andreas

    2013-01-01

    This review on elbow dislocations describes ligament and bone injuries as well as the typical injury mechanisms and the main classifications of elbow dislocations. Current treatment concepts of simple, that is, stable, or complex unstable elbow dislocations are outlined by means of case reports. Special emphasis is put on injuries to the medial ulnar collateral ligament (MUCL) and on posttraumatic elbow stiffness. PMID:24228180

  13. Multiscale modeling of dislocation-precipitate interactions in Fe: From molecular dynamics to discrete dislocations.

    PubMed

    Lehtinen, Arttu; Granberg, Fredric; Laurson, Lasse; Nordlund, Kai; Alava, Mikko J

    2016-01-01

    The stress-driven motion of dislocations in crystalline solids, and thus the ensuing plastic deformation process, is greatly influenced by the presence or absence of various pointlike defects such as precipitates or solute atoms. These defects act as obstacles for dislocation motion and hence affect the mechanical properties of the material. Here we combine molecular dynamics studies with three-dimensional discrete dislocation dynamics simulations in order to model the interaction between different kinds of precipitates and a 1/2〈111〉{110} edge dislocation in BCC iron. We have implemented immobile spherical precipitates into the ParaDis discrete dislocation dynamics code, with the dislocations interacting with the precipitates via a Gaussian potential, generating a normal force acting on the dislocation segments. The parameters used in the discrete dislocation dynamics simulations for the precipitate potential, the dislocation mobility, shear modulus, and dislocation core energy are obtained from molecular dynamics simulations. We compare the critical stresses needed to unpin the dislocation from the precipitate in molecular dynamics and discrete dislocation dynamics simulations in order to fit the two methods together and discuss the variety of the relevant pinning and depinning mechanisms. PMID:26871192

  14. Job Enrichment and the Mentally Retarded Worker.

    ERIC Educational Resources Information Center

    Morris, Jerry L.; And Others

    1981-01-01

    The effect of job enrichment on the production rate of 14 mentally retarded adult workers was evaluated. Job enrichment led to increases in standard rates of production for high IQ Ss and lower rates for low IQ Ss. (Author)

  15. TRAINING METHODS FOR OLDER WORKERS. EMPLOYMENT OF OLDER WORKERS, 2.

    ERIC Educational Resources Information Center

    BELBIN, R.M.

    A SURVEY WAS PRESENTED OF SCIENTIFIC KNOWLEDGE ON AGE CHANGES IN HUMAN CAPACITIES, ESPECIALLY IN LEARNING ABILITY AND ADAPTABILITY, AND DESCRIBED VARIOUS METHODS USED TO TRAIN WORKERS OVER 40. THE ROLE OF MEMORY, MOTIVATION, RIGIDITY, AND INTELLIGENCE IN DETERMINING THE LEARNING EFFICIENCY OF MATURE ADULTS WAS ASSESSED, ALSO DIFFICULTIES CAUSED BY…

  16. Identifying foot fractures and dislocations.

    PubMed

    Caswell, Fiona; Brown, Craig

    2014-10-01

    As the roles of emergency nurse practitioners expand, more patients with minor injuries are being managed independently by nursing staff. Injuries to the foot and ankle are common among such patients, and X-rays are frequently performed to aid their diagnoses. Some of these fractures and dislocations are subtle and difficult to identify, so practitioners must adopt a structured approach to reading X-rays. This article describes some of these injuries and offers advice, including X-ray illustrations, on how to identify them. PMID:25270819

  17. Quantum dislocations in solid Helium-4

    NASA Astrophysics Data System (ADS)

    Aleinikava, Darya

    In this thesis the following problems on properties of solid 4He are considered: (i) the role of long-range interactions in suppression of dislocation roughening at T = 0; (ii) the combined effect of 3He impurities and Peierls potential on shear modulus softening; (iii) the dislocation superclimb and its connection to the phenomenon of "giant isochoric compressibility"; (iv) non-linear dislocation response to the applied stress and stress-induces dislocation roughening as a I-order phase transition in 1D at finite temperature. First we investigate the effect of long-range interactions on the state of edge dislocation at T = 0. Such interactions are induced by elastic forces of the solid. We found that quantum roughening transition of a dislocation at T = 0 is completely suppressed by arbitrarily small long-range interactions between kinks. A heuristic argument is presented and the result has been verified by numerical Monte-Carlo simulations using Worm Algorithm in J-current model. It was shown that the Peierls potential plays a crucial role in explaining the elastic properties of dislocations, namely shear modulus softening phenomenon. The crossover from T = 0 to finite temperatures leads to intrinsic softening of the shear modulus and is solely controlled by kink typical energy. It was demonstrated that the mechanism, involving only the binding of 3He impurities to the dislocations, requires an unrealistically high concentrations of defects (or impurities) in order to explain the shear modulus phenomenon and therefore an inclusion of Peierls potential in consideration is required. Superclimbing dislocations, that is the edge dislocations with the superfluidity along the core, were investigated. The theoretical prediction that superclimb is responsible for the phenomenon of "giant isochoric compressibility" was confirmed by Monte-Carlo simulations. It was demonstrated that the isochoric compressibility is suppressed at low temperatures. The dependence of

  18. Gatekeeper Training for Youth Workers

    ERIC Educational Resources Information Center

    Cartmill, Tania; Deane, Frank; Wilson, Coralie

    2009-01-01

    Adults who act as gatekeepers for young people may have the same barriers to help-seeking for mental health issues as young people. This study investigated the personal help-seeking practices of 47 Australian youth workers prior to and after a training workshop on youth mental health issues. Pre-post workshop evaluation revealed some increases in…

  19. No place like home? Potential pathways to loneliness in older adults under the care of a live-in foreign home care worker.

    PubMed

    Ayalon, Liat; Shiovitz-Ezra, Sharon; Palgi, Yuval

    2012-01-01

    The arrangement in which frail older adults from the developed world are cared for in their homes by individuals from the developing world has become increasingly prevalent worldwide. In Israel, this arrangement is termed foreign home care. In this article, the authors first describe the global phenomenon of foreign home care of frail older adults as well as the more local characteristics of this arrangement in Israel. The authors then describe the concept of loneliness. Based on empirical and theoretical knowledge in the field of loneliness, the authors argue that older adults under live-in foreign home care may be particularly prone to feelings of loneliness for several reasons: some that are general to older adults with cognitive or physical disability and others that are specific to this particular caregiving arrangement. The authors conclude by providing ideas for future practice and research on this highly vulnerable group that, to date, has received only minimal research attention. PMID:22303620

  20. Dislocated interests and climate change

    NASA Astrophysics Data System (ADS)

    Davis, Steven J.; Diffenbaugh, Noah

    2016-06-01

    The predicted effects of climate change on surface temperatures are now emergent and quantifiable. The recent letter by Hansen and Sato (2016 Environ. Res. Lett. 11 034009) adds to a growing number of studies showing that warming over the past four decades has shifted the distribution of temperatures higher almost everywhere, with the largest relative effects on summer temperatures in developing regions such as Africa, South America, southeast Asia, and the Middle East (e.g., Diffenbaugh and Scherer 2011 Clim. Change 107 615–24 Anderson 2011 Clim. Change 108 581; Mahlstein et al 2012 Geophys. Res. Lett. 39 L21711). Hansen and Sato emphasize that although these regions are warming disproportionately, their role in causing climate change—measured by cumulative historical CO2 emissions produced—is small compared to the US and Europe, where the relative change in temperatures has been less. This spatial and temporal mismatch of climate change impacts and the burning of fossil fuels is a critical dislocation of interests that, as the authors note, has ‘substantial implications for global energy and climate policies.’ Here, we place Hansen and Sato’s ‘national responsibilities’ into a broader conceptual framework of problematically dislocated interests, and briefly discuss the related challenges for global climate mitigation efforts.

  1. Dislocation-Free Czochralski Silicon Crystal Growth without the Dislocation-Elimination-Necking Process

    NASA Astrophysics Data System (ADS)

    Hoshikawa, Keigo; Huang, Xinming; Taishi, Toshinori; Kajigaya, Tomio; Iino, Takayuki

    1999-12-01

    Dislocation-free silicon crystals have been grown successfully from heavily-boron-doped silicon melts by the Czochralski method without the dislocation-elimination-necking process (Dash neck). A dislocation-free silicon seed of <001> orientation with a boron concentration of about 4×1019 atoms/cm3 was used to grow a silicon crystal with the same boron concentration. No dislocation was generated in the seed during the dipping process, and no misfit dislocation occurred in the grown crystal. These results show that shoulder and body growth can be started immediately after the seeding process.

  2. A rare variant of knee dislocation

    PubMed Central

    HUSSIN, P.; MAWARDI, M.; AB HALIM, A.H.

    2016-01-01

    Knee dislocation is a rare injury. It represents less than 0.2% of orthopaedic injuries. This case reports a rare form of knee dislocation caused by the impact of a high-energy trauma. In these cases the appropriate assessment and management is needed to ensure that patient receives the proper treatment. PMID:27381692

  3. A Bilateral Traumatic Hip Obturator Dislocation

    PubMed Central

    Karaarslan, Ahmet Adnan; Acar, Nihat; Karci, Tolga; Sesli, Erhan

    2016-01-01

    A case of a bilateral simultaneous traumatic obturator dislocation of both hip joints in an 18-year-old young man following a traffic accident is presented. We reduced the dislocated femoral heads immediately under general anesthesia followed by passive and active exercises and early full-weight bearing mobilization. After 5 years, the result was excellent. PMID:26977327

  4. Dislocation generation during early stage sintering.

    NASA Technical Reports Server (NTRS)

    Sheehan, J. E.; Lenel, F. V.; Ansell, G. S.

    1973-01-01

    Discussion of the effects of capillarity-induced stresses on dislocations during early stage sintering. A special version of Hirth's (1963) theoretical calculation procedures modified to describe dislocation nucleation on planes meeting the sintering body's neck surface obliquely is shown to predict plastic flow at stress levels know to exist between micron size metal particles in the early stages of sintering.

  5. Intermittent dislocation flow in viscoplastic deformation.

    PubMed

    Miguel, M C; Vespignani, A; Zapperi, S; Weiss, J; Grasso, J R

    2001-04-01

    The viscoplastic deformation (creep) of crystalline materials under constant stress involves the motion of a large number of interacting dislocations. Analytical methods and sophisticated 'dislocation dynamics' simulations have proved very effective in the study of dislocation patterning, and have led to macroscopic constitutive laws of plastic deformation. Yet, a statistical analysis of the dynamics of an assembly of interacting dislocations has not hitherto been performed. Here we report acoustic emission measurements on stressed ice single crystals, the results of which indicate that dislocations move in a scale-free intermittent fashion. This result is confirmed by numerical simulations of a model of interacting dislocations that successfully reproduces the main features of the experiment. We find that dislocations generate a slowly evolving configuration landscape which coexists with rapid collective rearrangements. These rearrangements involve a comparatively small fraction of the dislocations and lead to an intermittent behaviour of the net plastic response. This basic dynamical picture appears to be a generic feature in the deformation of many other materials. Moreover, it should provide a framework for discussing fundamental aspects of plasticity that goes beyond standard mean-field approaches that see plastic deformation as a smooth laminar flow. PMID:11287948

  6. Microscopically derived free energy of dislocations

    NASA Astrophysics Data System (ADS)

    Kooiman, M.; Hütter, M.; Geers, M. G. D.

    2015-05-01

    The dynamics of large amounts of dislocations is the governing mechanism in metal plasticity. The free energy of a continuous dislocation density profile plays a crucial role in the description of the dynamics of dislocations, as free energy derivatives act as the driving forces of dislocation dynamics. In this contribution, an explicit expression for the free energy of straight and parallel dislocations with different Burgers vectors is derived. The free energy is determined using systematic coarse-graining techniques from statistical mechanics. The starting point of the derivation is the grand-canonical partition function derived in an earlier work, in which we accounted for the finite system size, discrete glide planes and multiple slip systems. In this paper, the explicit free energy functional of the dislocation density is calculated and has, to the best of our knowledge, not been derived before in the present form. The free energy consists of a mean-field elastic contribution and a local defect energy, that can be split into a statistical and a many-body contribution. These depend on the density of positive and negative dislocations on each slip system separately, instead of GND-based quantities only. Consequently, a crystal plasticity model based on the here obtained free energy, should account for both statistically stored and geometrically necessary dislocations.

  7. Geometric approach to dislocation and disclination theory

    SciTech Connect

    Nesterov, A.I.; Ovchinnikov, S.G.

    1988-05-01

    Cartan structure equations are used to create a four-dimensional geometric description of dislocations in continuum theory. It is shown that the dislocation distribution is determined by the torsion tensor, while the disclination distribution is determined by the curvature tensor. An analogy to electrodynamics is offered.

  8. Statistics of dislocation pinning at localized obstacles

    SciTech Connect

    Dutta, A.; Bhattacharya, M. Barat, P.

    2014-10-14

    Pinning of dislocations at nanosized obstacles like precipitates, voids, and bubbles is a crucial mechanism in the context of phenomena like hardening and creep. The interaction between such an obstacle and a dislocation is often studied at fundamental level by means of analytical tools, atomistic simulations, and finite element methods. Nevertheless, the information extracted from such studies cannot be utilized to its maximum extent on account of insufficient information about the underlying statistics of this process comprising a large number of dislocations and obstacles in a system. Here, we propose a new statistical approach, where the statistics of pinning of dislocations by idealized spherical obstacles is explored by taking into account the generalized size-distribution of the obstacles along with the dislocation density within a three-dimensional framework. Starting with a minimal set of material parameters, the framework employs the method of geometrical statistics with a few simple assumptions compatible with the real physical scenario. The application of this approach, in combination with the knowledge of fundamental dislocation-obstacle interactions, has successfully been demonstrated for dislocation pinning at nanovoids in neutron irradiated type 316-stainless steel in regard to the non-conservative motion of dislocations. An interesting phenomenon of transition from rare pinning to multiple pinning regimes with increasing irradiation temperature is revealed.

  9. Statistics of dislocation pinning at localized obstacles

    NASA Astrophysics Data System (ADS)

    Dutta, A.; Bhattacharya, M.; Barat, P.

    2014-10-01

    Pinning of dislocations at nanosized obstacles like precipitates, voids, and bubbles is a crucial mechanism in the context of phenomena like hardening and creep. The interaction between such an obstacle and a dislocation is often studied at fundamental level by means of analytical tools, atomistic simulations, and finite element methods. Nevertheless, the information extracted from such studies cannot be utilized to its maximum extent on account of insufficient information about the underlying statistics of this process comprising a large number of dislocations and obstacles in a system. Here, we propose a new statistical approach, where the statistics of pinning of dislocations by idealized spherical obstacles is explored by taking into account the generalized size-distribution of the obstacles along with the dislocation density within a three-dimensional framework. Starting with a minimal set of material parameters, the framework employs the method of geometrical statistics with a few simple assumptions compatible with the real physical scenario. The application of this approach, in combination with the knowledge of fundamental dislocation-obstacle interactions, has successfully been demonstrated for dislocation pinning at nanovoids in neutron irradiated type 316-stainless steel in regard to the non-conservative motion of dislocations. An interesting phenomenon of transition from rare pinning to multiple pinning regimes with increasing irradiation temperature is revealed.

  10. Dislocation patterning in a two-dimensional continuum theory of dislocations

    NASA Astrophysics Data System (ADS)

    Groma, István; Zaiser, Michael; Ispánovity, Péter Dusán

    2016-06-01

    Understanding the spontaneous emergence of dislocation patterns during plastic deformation is a long standing challenge in dislocation theory. During the past decades several phenomenological continuum models of dislocation patterning were proposed, but few of them (if any) are derived from microscopic considerations through systematic and controlled averaging procedures. In this paper we present a two-dimensional continuum theory that is obtained by systematic averaging of the equations of motion of discrete dislocations. It is shown that in the evolution equations of the dislocation densities diffusionlike terms neglected in earlier considerations play a crucial role in the length scale selection of the dislocation density fluctuations. It is also shown that the formulated continuum theory can be derived from an averaged energy functional using the framework of phase field theories. However, in order to account for the flow stress one has in that case to introduce a nontrivial dislocation mobility function, which proves to be crucial for the instability leading to patterning.

  11. Dislocation core in GaN

    SciTech Connect

    Liliental-Weber, Zuzanna; Jasinski, Jacek B.; Washburn, Jack; O'Keefe, Michael A.

    2002-02-20

    Light emitting diodes and blue laser diodes grown on GaN have been demonstrated despite six orders of magnitude higher dislocation density than that for III-V arsenide and phosphide diodes. Understanding and determination of dislocation cores in GaN is crucial since both theoretical and experimental work are somewhat contradictory. Transmission Electron Microscopy (TEM) has been applied to study the layers grown by hydride vapor-phase epitaxy (HVPE) and molecular beam epitaxy (MBE) (under Ga rich conditions) in plan-view and cross-section samples. This study suggests that despite the fact that voids are formed along the dislocation line in HVPE material, the dislocations have closed cores. Similar results of closed core are obtained for the screw dislocation in the MBE material, confirming earlier studies.

  12. BILATERAL ANTERIOR GLENOHUMERAL DISLOCATION: CLINICAL CASE

    PubMed Central

    Silva, Luís Pires; Sousa, Cristina Varino; Rodrigues, Elisa; Alpoim, Bruno; Leal, Miguel

    2015-01-01

    Bilateral anterior glenohumeral dislocation is a rare occurrence. We present a case of bilateral anterior glenohumeral dislocation caused by a fall. The interest in publishing this case is that this is a clinical rarity with few cases reported in the literature. An 89-year-old female patient was brought to the emergency department after a fall, complaining of intense pain in both shoulders and inability to move them. Objective examination showed clinical signs giving the suspicion of bilateral anterior glenohumeral dislocation, which was confirmed by x-ray imaging. Both dislocations were successfully reduced in the emergency department using the modified Milch technique. When a synchronous and symmetrical force has acted on both shoulders and these are painful with significant functional limitation, the suspicion of bilateral glenohumeral dislocation is a differential diagnosis to be considered, even though it is rare. PMID:27047826

  13. Distribution of dislocations in nanostructured bainite

    SciTech Connect

    Cornide, J; Miyamoto, G; Caballero, Francesca G.; Furuhara, T; Miller, Michael K; Garcia-Mateo, C.

    2011-01-01

    The dislocation density in ferrite and austenite of a bainitic microstructure obtained by transformation at very low temperature (300 C) has been determined using transmission electron microscopy. Observations revealed that bainitic ferrite plates consist of two distinctive regions with different substructures. A central region in the ferrite plate is observed with dislocations that may result from lattice-invariant deformation at the earlier stage of bainite growth. As plastic deformation occurs in the surrounding austenite to accommodate the transformation strain as growth progresses, the Ferrite/Austenite interface has also a very distinctive dislocation profile. In addition, atom-probe tomography suggested that dislocation tangles observed in the vicinity of the ferrite/austenite interface might trap higher amount of carbon than single dislocations inside the bainitic ferrite plate.

  14. Arthroscopic Treatment of Perilunate Dislocations and Fracture Dislocations

    PubMed Central

    Kim, Jong Pil; Lee, Jae Sung; Park, Min Jong

    2015-01-01

    Background The key to a successful result in the treatment of perilunate dislocations (PLDs) and fracture-dislocations (PLFDs) is the restoration of normal alignment of the carpal bones, followed by stable maintenance until healing. This article aimed to assess whether arthroscopic techniques are a reliable surgical option for the treatment of this challenging injury. Materials and Methods Twenty patients with an acute PLD or PLFD were treated by an arthroscopic technique. They were retrospectively reviewed at an average follow-up of 31.2 months (range 18–61 months). Functional outcomes were assessed with the Modified Mayo Wrist Score (MMWS), Disabilities of the Arm, Shoulder, and Hand (DASH) questionnaire, and Patient-Rated Wrist Evaluation (PRWE) score as well as radiographic evaluations. Description of Technique Arthroscopic reduction and percutaneous fixation was performed to the scapholunate and lunotriquetral intervals using Kirschner wires (K-wires) as joysticks as well as to the scaphoid using a cannulated headless screw for transscaphoid-type injuries. The K-wires were removed at 10 weeks postoperation. Results Overall functional outcomes according to the MMWS were rated as excellent in three patients, good in eight, fair in seven, and poor in two. The mean DASH score was 18, and the mean PRWE score was 30. On the basis of radiographic parameters, reduction obtained at the operation was maintained within normal ranges in 15 patients. No patient had developed arthritis by the last follow-up. Conclusions The medium-term results show that arthroscopic treatment can provide proper restoration and stable fixation of carpal alignment and results in satisfactory functional and radiologic outcomes for acute perilunate injuries. Level of Evidence Level IV. PMID:25945291

  15. Recurrent Dislocation of the Patella

    PubMed Central

    Benítez, Gustavo

    2015-01-01

    Purpose: To evaluate results of medial patellofemoral ligament (MPFL) reconstruction associated with lateral release and advancement of vastus medialis in recurrent dislocation of the patella. Methods: We retrospectively evaluated 11 patients with a mean follow-up of 19 months. Mean age was 23, mainly women. We did MPFL reconstruction with semitendinosus or gracilis tendon depending on BMI, associated with advancement of vastus medialis and lateral release. Results: Mean Kujala score improved from 46,54 pts. preoperative to 88,36 postoperative. Our main complication was 1 patient with rigid knee, who required movilization under anesthesia and arthroscopic arthrolisis to improve her outcome. Conclusion: The combination of this techniques are a good alternative to treat patients with recurrent patella disclocation, with good short and mid-term results. Biomechanic intra and postop complications of MPFL reconstruction are related to patellar fixation, anatomic positioning of femoral tunnel and knee position of the graft fixation.

  16. Dislocation Creep in Magnesium Calcite

    NASA Astrophysics Data System (ADS)

    Xu, L.; Xiao, X.; Evans, B. J.

    2003-12-01

    To investigate the effect of dissolved Mg on plastic deformation of calcite, we performed triaxial deformation experiments on synthetic calcite with varying amount of Mg content. Mixtures of powders of calcite and dolomite were isostatically hot pressed (HIP) at 850° C and 300 MPa confining pressure for different intervals (2 to 20hrs) resulting in homogeneous aggregates of high-magnesium calcite; Mg content varied from 0.07 to 0.17 mol%. Creep tests were performed at differential stresses from 20 to 160 MPa at 700 to 800° C. Grain sizes before and after deformation were determined from the images obtained from scanning electron microscope (SEM) and optical microscope. Grain sizes are in the range of 5 to 20 microns depending on the HIP time, and decrease with increasing magnesium content. Both BSE images and chemical analysis suggest that all dolomite are dissolved and the Mg distribution is homogeneous through the sample, after 2 hrs HIP. At stresses below 40 MPa, the samples deformed in diffusion region (Coble creep), as described previously by Herwegh. The strength decreases with increasing magnesium content, owing to the difference of grain size. At stresses above 80 MPa, the stress exponent is greater than 3, indicating an increased contribution of dislocation creep. The transition between diffusion to dislocation creep occurs at higher stresses for the samples with higher magnesium content and smaller grain size. Preliminary data suggests a slight increase in strength with increasing magnesium content, but more tests are needed to verify this effect. In a few samples, some strain weakening may have been evident. The activation energy in the transition region (at 80 MPa) is ˜200 KJ/mol with no dependence on magnesium content, agreeing with previous measurements of diffusion creep in natural and synthetic marbles.

  17. Continuum framework for dislocation structure, energy and dynamics of dislocation arrays and low angle grain boundaries

    NASA Astrophysics Data System (ADS)

    Zhu, Xiaohong; Xiang, Yang

    2014-09-01

    We present a continuum framework for dislocation structure, energy and dynamics of dislocation arrays and low angle grain boundaries that are allowed to be nonplanar or nonequilibrium. In our continuum framework, we define a dislocation density potential function on the dislocation array surface or grain boundary to describe the orientation dependent continuous distribution of dislocations in a very simple and accurate way. The continuum formulations incorporate both the long-range dislocation interaction and the local dislocation line energy, and are derived from the discrete dislocation model. The continuum framework recovers the classical Read-Shockley energy formula when the long-range elastic fields of the low angle grain boundaries are canceled out. Applications of our continuum framework in this paper are focused on dislocation structures on static planar and nonplanar low angle grain boundaries and misfitting interfaces. We present two methods under our continuum framework for this purpose, including the method based on the Franks formula and the energy minimization method. We show that for any (planar or nonplanar) low angle grain boundary, the Franks formula holds if and only if the long-range stress field in the continuum model is canceled out, and it does not necessarily hold for a total energy minimum dislocation structure.

  18. Evolution, Interaction, and Intrinsic Properties of Dislocations in Intermetallics: Anisotropic 3D Dislocation Dynamics Approach

    SciTech Connect

    Qian Chen

    2008-08-18

    The generation, motion, and interaction of dislocations play key roles during the plastic deformation process of crystalline solids. 3D Dislocation Dynamics has been employed as a mesoscale simulation algorithm to investigate the collective and cooperative behavior of dislocations. Most current research on 3D Dislocation Dynamics is based on the solutions available in the framework of classical isotropic elasticity. However, due to some degree of elastic anisotropy in almost all crystalline solids, it is very necessary to extend 3D Dislocation Dynamics into anisotropic elasticity. In this study, first, the details of efficient and accurate incorporation of the fully anisotropic elasticity into 3D discrete Dislocation Dynamics by numerically evaluating the derivatives of Green's functions are described. Then the intrinsic properties of perfect dislocations, including their stability, their core properties and disassociation characteristics, in newly discovered rare earth-based intermetallics and in conventional intermetallics are investigated, within the framework of fully anisotropic elasticity supplemented with the atomistic information obtained from the ab initio calculations. Moreover, the evolution and interaction of dislocations in these intermetallics as well as the role of solute segregation are presented by utilizing fully anisotropic 3D dislocation dynamics. The results from this work clearly indicate the role and the importance of elastic anisotropy on the evolution of dislocation microstructures, the overall ductility and the hardening behavior in these systems.

  19. Thermodynamic forces in single crystals with dislocations

    NASA Astrophysics Data System (ADS)

    Van Goethem, Nicolas

    2014-06-01

    A simple model for the evolution of macroscopic dislocation regions in a single crystal is presented. This model relies on maximal dissipation principle within Kröner's geometric description of the dislocated crystal. Mathematical methods and tools from shape optimization theory provide equilibrium relations at the dislocation front, similarly to previous work achieved on damage modelling (J Comput Phys 33(16):5010-5044, 2011). The deformation state variable is the incompatible strain as related to the dislocation density tensor by a relation involving the Ricci curvature of the crystal underlying elastic metric. The time evolution of the model variables follows from a novel interpretation of the Einstein-Hilbert flow in terms of dislocation microstructure energy. This flow is interpreted as the dissipation of non-conservative dislocations, due to the climb mechanism, modelled by an average effect of mesoscopic dislocations moving normal to their glide planes by adding or removing points defects. The model equations are a fourth-order tensor parabolic equation involving the operator "incompatibility," here appearing as a tensorial counterpart of the scalar Laplacian. This work encompasses and generalizes results previously announced (C R Acad Sci Paris Ser I 349:923-927, 2011), with in addition a series of physical interpretations to give a meaning to the newly introduced concepts.

  20. Ultrasonic Study of Dislocation Dynamics in Lithium -

    NASA Astrophysics Data System (ADS)

    Han, Myeong-Deok

    1987-09-01

    Experimental studies of dislocation dynamics in LiF single crystals, using ultrasonic techniques combined with dynamic loading, were performed to investigate the time evolution of the plastic deformation process under a short stress pulse at room temperature, and the temperature dependence of the dislocation damping mechanism in the temperature range 25 - 300(DEGREES)K. From the former, the time dependence of the ultrasonic attenuation was understood as resulting from dislocation multiplication followed by the evolution of mobile dislocations to immobile ones under large stress. From the latter, the temperature dependence of the ultrasonic attenuation was interpreted as due to the motion of the dislocation loops overcoming the periodic Peierls potential barrier in a manner analogous to the motion of a thermalized sine-Gordon chain under a small stress. The Peierls stress obtained from the experimental results by application of Seeger's relaxation model with exponential dislocation length distribution was 4.26MPa, which is consistent with the lowest stress for the linear relation between the dislocation velocity and stress observed by Flinn and Tinder.

  1. Adult Education in Australia: The Council of Adult Education.

    ERIC Educational Resources Information Center

    Randell, Shirley

    Liberal adult education in Victoria, Australia, takes its ideals, if not its form, from the pre-war university and Workers Education Association (WEA) partnerships: the university providing tutors and content, the WEA providing contact with unions and workers. Unique to Victoria is the level to which community-based adult education has been…

  2. Worker Mobility in the U.S. Economy. [Executive Summary.] Research Report Series RR-86-24.

    ERIC Educational Resources Information Center

    Zornitsky, Jeffrey; And Others

    A study conducted as part of a project concerned with the increasing internationalization of the U.S. economy addressed three questions: (1) whether the rate of worker mobility kept pace with changing labor demand, and if not, what strategies might be used to increase it; (2) when faced with dislocation, whether workers responded by migrating…

  3. Monteggia fracture-dislocations: A Historical Review

    PubMed Central

    Rehim, Shady A.; Maynard, Mallory A.; Sebastin, Sandeep J.; Chung, Kevin C.

    2014-01-01

    The eponym Monteggia fracture-dislocation originally referred to a fracture of the shaft of the ulna accompanied by anterior dislocation of the radial head that was described by Giovanni Battista Monteggia of Italy in 1814. Subsequently, a further classification system based on the direction of the radial head dislocation and associated fractures of the radius and ulna was proposed by Jose Luis Bado of Uruguay in 1958. This article investigates the evolution of treatment, classification, and outcomes of the Monteggia injury and sheds light on the lives and contributions of Monteggia and Bado. PMID:24792923

  4. Dislocation punching from ceramic/metal interfaces

    SciTech Connect

    Taya, M. ); Mori, T. . Dept. of Materials Science and Engineering)

    1994-07-01

    Relaxation of misfit strains at interfaces between two different materials by dislocation punching is studied analytically by focusing on two types of interfaces: planar and nonplanar. As an example of planar type interface, the case of metal coating/ceramic substrate system is studied while ceramic filler/metal matrix composite system is examined as an example of a nonplanar interface. Based on the present analytical model, the condition for dislocation punching for each interface is established. Validity of the dislocation punching model is verified by comparing the analytical results with limited experimental results, resulting in a good agreement.

  5. Intrauterine Temporomandibular Joint Dislocation: Prenatal Sonographic Evaluation

    PubMed Central

    Çil, Ahmet Said; Bozkurt, Murat; Bozkurt, Duygu Kara

    2014-01-01

    Congenital temporomandibular joint (TMJ) diseases are very rare disorders and are usually diagnosed in childhood. Developmental disorders of the TMJ such as hypoplasia, hyperplasia, and aplasia of the TMJ compartments are characterized by TMJ dysfunction. In childhood, these patients experience recurrent dislocation, pain, and malocclusion. We present the case of a 25-week fetus with unilateral TMJ dislocation with fluid retention in the joint diagnosed by ultrasonography. To the best of our knowledge, this is the first case of TMJ dislocation diagnosed by ultrasonographic evaluation during the prenatal period. PMID:23669613

  6. Intrauterine temporomandibular joint dislocation: prenatal sonographic evaluation.

    PubMed

    Çil, Ahmet Said; Bozkurt, Murat; Bozkurt, Duygu Kara

    2014-09-01

    Congenital temporomandibular joint (TMJ) diseases are very rare disorders and are usually diagnosed in childhood. Developmental disorders of the TMJ such as hypoplasia, hyperplasia, and aplasia of the TMJ compartments are characterized by TMJ dysfunction. In childhood, these patients experience recurrent dislocation, pain, and malocclusion. We present the case of a 25-week fetus with unilateral TMJ dislocation with fluid retention in the joint diagnosed by ultrasonography. To the best of our knowledge, this is the first case of TMJ dislocation diagnosed by ultrasonographic evaluation during the prenatal period. PMID:23669613

  7. Structure of misfit dislocations in niobium-sapphire interfaces and strength of interfacial bonding: An atomistic study

    SciTech Connect

    Levay, A.; Moebus, G.; Vitek, V.; Ruehle, M.; Tichy, G.

    1999-11-12

    The formation of networks of misfit dislocations is investigated at the (0001){sub Al{sub 2}O{sub 3}}{parallel}(111){sub Nb} interface using a recently proposed approach which employs a very simple pair-potential to describe interaction between the metal and the substrate that contains the strength of interfacial adhesion as a parameter. The calculations demonstrate how the strength of bonding between the two materials decides both the form of the network and the atomic structure of the cores of these dislocations. At the same time it reveals that diffusion is essential for the formation of the observed triangular network of 1/2{l{underscore}angle}111{r{underscore}angle} dislocations. The calculated structures are then used to investigate related high resolution electron microscope (HREM) images using a multislice technique. In these simulations translational symmetry along the electron beam was not assumed but for each slice of material along the beam different sub-structures were used. This allowed us to investigate fully the effect of the dislocation intersections upon the images of the dislocation cores. Their effect is, indeed, considerable if an intersection is in the region producing the image but if not, the images of the cores of misfit dislocations are affected only marginally and HREM can capture fine details of the core structure. A direct comparison of an experimental observation in Mayer and co-workers with the present simulations demonstrates this ability.

  8. Canonical Quantization of Crystal Dislocation and Electron-Dislocation Scattering in an Isotropic Media

    NASA Astrophysics Data System (ADS)

    Li, Mingda; Cui, Wenping; Dresselhaus, M. S.; Chen, Gang; MIT Team; Boston College Team

    Crystal dislocations govern the plastic mechanical properties of materials but also affect the electrical and optical properties. However, a fundamental and decent quantum-mechanical theory of dislocation remains undiscovered for decades. Here we present an exact and manageable Hamiltonian theory for both edge and screw dislocation line in an isotropic media, where the effective Hamiltonian of a single dislocation line can be written in a harmonic-oscillator-like form, with closed-form quantized 1D phonon-like excitation. Moreover a closed-form, position dependent electron-dislocation coupling strength is obtained, from which we obtained good agreement of relaxation time when comparing with classical results. This Hamiltonian provides a platform to study the effect of dislocation to materials' non-mechanical properties from a fundamental Hamiltonian level.

  9. Fundamentals in generalized elasticity and dislocation theory of quasicrystals: Green tensor, dislocation key-formulas and dislocation loops

    NASA Astrophysics Data System (ADS)

    Lazar, Markus; Agiasofitou, Eleni

    2014-12-01

    The present work provides fundamental quantities in generalized elasticity and dislocation theory of quasicrystals. In a clear and straightforward manner, the three-dimensional Green tensor of generalized elasticity theory and the extended displacement vector for an arbitrary extended force are derived. Next, in the framework of dislocation theory of quasicrystals, the solutions of the field equations for the extended displacement vector and the extended elastic distortion tensor are given; that is, the generalized Burgers equation for arbitrary sources and the generalized Mura-Willis formula, respectively. Moreover, important quantities of the theory of dislocations as the Eshelby stress tensor, Peach-Koehler force, stress function tensor and the interaction energy are derived for general dislocations. The application to dislocation loops gives rise to the generalized Burgers equation, where the displacement vector can be written as a sum of a line integral plus a purely geometric part. Finally, using the Green tensor, all other dislocation key-formulas for loops, known from the theory of anisotropic elasticity, like the Peach-Koehler stress formula, Mura-Willis equation, Volterra equation, stress function tensor and the interaction energy are derived for quasicrystals.

  10. Traumatic Atlanto-occipital Dislocation (AOD)

    PubMed Central

    Kim, Yeon-Joon; Park, Chan-Woo; Lee, Sang-Gu; Son, Seong; Kim, Woo-Kyung

    2012-01-01

    Objective Traumatic atlanto-occipital dislocation (AOD) results from high energy trauma and is an uncommon and usually fatal injury due to an injury to the cervicomedullary junction. Recently, improved prehospital management, early diagnosis and effective treatment led to increasing reports of survival. This study of patients with AOD initial imaging modalities recognizes the clinical features and diagnostic considerations for a quick diagnosis. Methods In this article, five survived adult patients with traumatic AOD are presented and retrospectively reviewed. Diagnosis was made by lateral cervical spine x-ray, cervical computed tomography (CT), or magnetic resonance imaging(MRI). Treatment consisted of early immobilization, respiratory support, and subsequent occipitocervical fusion. Results Four patients were male and the other one was female. Three were diagnosed early and the others were delayed in confirmations. One was type I AOD and four were type II AOD. All patients were applied occipitocervical fusion. Two cases were worse; neurological states and the other three that showed no change. Lateral X-ray film of all patients in the prevertebral soft tissue swelling at the C2 level was noted. The mean thickness of prevertebral soft tissue C2 level was 17.88 mm(15.18 to 20.17mm). Two were in the normal range of dens-basion index(DBI), three showed abnormalities, and Power's ratio was abnormal in 3 patients. Conclusion As for damages caused by a strong external force in patients with severe prevertebral soft tissue swelling at C2 level abnormaly, the doctor determines whether more should be carefully AOD and considers 3D CT or MRI to confirm AOD in these patients. PMID:25983794

  11. Automated identification and indexing of dislocations in crystal interfaces

    SciTech Connect

    Stukowski, Alexander; Bulatov, Vasily V.; Arsenlis, Athanasios

    2012-10-31

    Here, we present a computational method for identifying partial and interfacial dislocations in atomistic models of crystals with defects. Our automated algorithm is based on a discrete Burgers circuit integral over the elastic displacement field and is not limited to specific lattices or dislocation types. Dislocations in grain boundaries and other interfaces are identified by mapping atomic bonds from the dislocated interface to an ideal template configuration of the coherent interface to reveal incompatible displacements induced by dislocations and to determine their Burgers vectors. Additionally, the algorithm generates a continuous line representation of each dislocation segment in the crystal and also identifies dislocation junctions.

  12. Model for dislocation locking by oxygen gettering in silicon crystals

    NASA Astrophysics Data System (ADS)

    Maroudas, Dimitris; Brown, Robert A.

    1991-04-01

    Oxygen gettering to dislocations slows and stops dislocation motion caused by applied stress in silicon crystals. A model is presented that quantitatively describes the inhibition of dislocation motion by accounting for the drag caused by the oxygen atmosphere in the crystal around the dislocation and for oxygen aggregates inside the dislocation core. The oxygen distribution is computed by analysis of diffusion and stress-assisted migration in the crystalline lattice. The predictions of the model agree quantitatively with the experimental data of Imai and Sumino. Hysteresis is predicted in the dependence of the dislocation velocity on applied stress and explains the difference in the unlocking and locking stresses for dislocation motion.

  13. Automated identification and indexing of dislocations in crystal interfaces

    DOE PAGESBeta

    Stukowski, Alexander; Bulatov, Vasily V.; Arsenlis, Athanasios

    2012-10-31

    Here, we present a computational method for identifying partial and interfacial dislocations in atomistic models of crystals with defects. Our automated algorithm is based on a discrete Burgers circuit integral over the elastic displacement field and is not limited to specific lattices or dislocation types. Dislocations in grain boundaries and other interfaces are identified by mapping atomic bonds from the dislocated interface to an ideal template configuration of the coherent interface to reveal incompatible displacements induced by dislocations and to determine their Burgers vectors. Additionally, the algorithm generates a continuous line representation of each dislocation segment in the crystal andmore » also identifies dislocation junctions.« less

  14. Dislocation dynamics simulations of interactions between gliding dislocations and radiation induced prismatic loops in zirconium

    NASA Astrophysics Data System (ADS)

    Drouet, Julie; Dupuy, Laurent; Onimus, Fabien; Mompiou, Frédéric; Perusin, Simon; Ambard, Antoine

    2014-06-01

    The mechanical behavior of Pressurized Water Reactor fuel cladding tubes made of zirconium alloys is strongly affected by neutron irradiation due to the high density of radiation induced dislocation loops. In order to investigate the interaction mechanisms between gliding dislocations and loops in zirconium, a new nodal dislocation dynamics code, adapted to Hexagonal Close Packed metals, has been used. Various configurations have been systematically computed considering different glide planes, basal or prismatic, and different characters, edge or screw, for gliding dislocations with -type Burgers vectors. Simulations show various interaction mechanisms such as (i) absorption of a loop on an edge dislocation leading to the formation of a double super-jog, (ii) creation of a helical turn, on a screw dislocation, that acts as a strong pinning point or (iii) sweeping of a loop by a gliding dislocation. It is shown that the clearing of loops is more favorable when the dislocation glides in the basal plane than in the prismatic plane explaining the easy dislocation channeling in the basal plane observed after neutron irradiation by transmission electron microscopy.

  15. Complete dorsal dislocation of the carpal scaphoid with perilunate dorsal dislocation

    PubMed Central

    Kang, Jong Woo; Park, Jong Hoon; Suh, Dong Hun; Park, Jong Woong

    2016-01-01

    Complete dorsal dislocation of the carpal scaphoid combined with dorsal perilunate dislocation is an extremely rare carpal injury. We describe the case of a 23-year-old man who presented with a complete dorsal dislocation of the carpal scaphoid, combined with a perilunate dislocation. Surgical treatment was performed with open reduction and interosseus ligament repair. At 4 years follow up, the patient's wrist pain had completely resolved without limitations of wrist joint motion and without evidence of avascular necrosis of the carpal scaphoid. PMID:27512229

  16. Energy and entropy of interacting dislocations

    SciTech Connect

    Ladd, A.J.C.; Hoover, W.G.

    1982-11-15

    The energy and entropy of interacting edge dislocations have been calculated by atomistic simulations, with the use of piecewise-linear forces in a two-dimensional triangular lattice. We conclude that the interaction energy between small groups of dislocations is well described by continuum mechanics for separations greater than a few lattice spacings. Our calculations enable us to make a precise determination of the core energy, which is an essential parameter in determining dislocation multiplication rates. We find also that continuum mechanics gives an accurate representation of the interaction of a dislocation pair with a homogeneous elastic stress field. The vibrational contribution to the entropy of such a pair is small, about 0.3k.

  17. Quenched pinning and collective dislocation dynamics

    PubMed Central

    Ovaska, Markus; Laurson, Lasse; Alava, Mikko J.

    2015-01-01

    Several experiments show that crystalline solids deform in a bursty and intermittent fashion. Power-law distributed strain bursts in compression experiments of micron-sized samples, and acoustic emission energies from larger-scale specimens, are the key signatures of the underlying critical-like collective dislocation dynamics - a phenomenon that has also been seen in discrete dislocation dynamics (DDD) simulations. Here we show, by performing large-scale two-dimensional DDD simulations, that the character of the dislocation avalanche dynamics changes upon addition of sufficiently strong randomly distributed quenched pinning centres, present e.g. in many alloys as immobile solute atoms. For intermediate pinning strength, our results adhere to the scaling picture of depinning transitions, in contrast to pure systems where dislocation jamming dominates the avalanche dynamics. Still stronger disorder quenches the critical behaviour entirely. PMID:26024505

  18. Developmental Dislocation (Dysplasia) of the Hip (DDH)

    MedlinePlus

    ... developmental dysplasia (dislocation) of the hip (DDH), the hip joint has not formed normally. The ball is loose ... be taken to provide detailed pictures of the hip joint. Treatment When DDH is detected at birth, it ...

  19. Quenched pinning and collective dislocation dynamics.

    PubMed

    Ovaska, Markus; Laurson, Lasse; Alava, Mikko J

    2015-01-01

    Several experiments show that crystalline solids deform in a bursty and intermittent fashion. Power-law distributed strain bursts in compression experiments of micron-sized samples, and acoustic emission energies from larger-scale specimens, are the key signatures of the underlying critical-like collective dislocation dynamics - a phenomenon that has also been seen in discrete dislocation dynamics (DDD) simulations. Here we show, by performing large-scale two-dimensional DDD simulations, that the character of the dislocation avalanche dynamics changes upon addition of sufficiently strong randomly distributed quenched pinning centres, present e.g. in many alloys as immobile solute atoms. For intermediate pinning strength, our results adhere to the scaling picture of depinning transitions, in contrast to pure systems where dislocation jamming dominates the avalanche dynamics. Still stronger disorder quenches the critical behaviour entirely. PMID:26024505

  20. Dislocation shielding of a cohesive crack

    NASA Astrophysics Data System (ADS)

    Bhandakkar, Tanmay K.; Chng, Audrey C.; Curtin, W. A.; Gao, Huajian

    2010-04-01

    Dislocation interaction with a cohesive crack is of increasing importance to computational modelling of crack nucleation/growth and related toughening mechanisms in confined structures and under cyclic fatigue conditions. Here, dislocation shielding of a Dugdale cohesive crack described by a rectangular traction-separation law is studied. The shielding is completely characterized by three non-dimensional parameters representing the effective fracture toughness, the cohesive strength, and the distance between the dislocations and the crack tip. A closed form analytical solution shows that, while the classical singular crack model predicts that a dislocation can shield or anti-shield a crack depending on the sign of its Burgers vector, at low cohesive strengths a dislocation always shields the cohesive crack irrespective of the Burgers vector. A numerical study shows the transition in shielding from the classical solution of Lin and Thomson (1986) in the high strength limit to the solution in the low strength limit. An asymptotic analysis yields an approximate analytical model for the shielding over the full range of cohesive strengths. A discrete dislocation (DD) simulation of a large (>10 3) number of edge dislocations interacting with a cohesive crack described by a trapezoidal traction-separation law confirms the transition in shielding, showing that the cohesive crack does behave like a singular crack at very high cohesive strengths (˜7 GPa), but that significant deviations in shielding between singular and cohesive crack predictions arise at cohesive strengths around 1GPa, consistent with the analytic models. Both analytical and numerical studies indicate that an appropriate crack tip model is essential for accurately quantifying dislocation shielding for cohesive strengths in the GPa range.

  1. Dislocation dynamics of web type silicon ribbon

    NASA Technical Reports Server (NTRS)

    Dillon, O. W., Jr.; Tsai, C. T.; De Angelis, R. J.

    1987-01-01

    Silicon ribbon grown by the dendritic web process passes through a rapidly changing thermal profile in the growth direction. This rapidly changing profile induces stresses which produce changes in the dislocation density in the ribbon. A viscoplastic material response function (Haasen-Sumino model) is used herein to calculate the stresses and the dislocation density at each point in the silicon ribbon. The residual stresses are also calculated.

  2. Isolated Proximal Tibiofibular Dislocation during Soccer

    PubMed Central

    Chiu, Casey; Sheele, Johnathan Michael

    2015-01-01

    Proximal tibiofibular dislocations are rarely encountered in the Emergency Department (ED). We present a case involving a man presenting to the ED with left knee pain after making a sharp left turn on the soccer field. His physical exam was only remarkable for tenderness over the lateral fibular head. His X-rays showed subtle abnormalities of the tibiofibular joint. The dislocation was reduced and the patient was discharged from the ED with orthopedic follow-up. PMID:26713164

  3. Atomistic modeling of dislocation-interface interactions

    SciTech Connect

    Wang, Jian; Valone, Steven M; Beyerlein, Irene J; Misra, Amit; Germann, T. C.

    2011-01-31

    Using atomic scale models and interface defect theory, we first classify interface structures into a few types with respect to geometrical factors, then study the interfacial shear response and further simulate the dislocation-interface interactions using molecular dynamics. The results show that the atomic scale structural characteristics of both heterophases and homophases interfaces play a crucial role in (i) their mechanical responses and (ii) the ability of incoming lattice dislocations to transmit across them.

  4. Investigation of the Dynamics of a Screw Dislocation in Copper

    NASA Astrophysics Data System (ADS)

    Kolupaeva, S. N.; Petelina, Yu. P.; Polosukhin, K. A.; Petelin, A. E.

    2015-08-01

    A modification of the mathematical model of forming the crystallographic shear band is proposed in which the strength of elastic interaction between all dislocations of the forming dislocation pileups is taken into account in addition to the Peach-Keller force; lattice, impurity, and dislocation friction; linear tension; viscous braking; and intensity of generation of point defects behind kinks. The model is used to investigate the influence of the dislocation density on the time characteristics of the formation of dislocation loops in copper.

  5. Dislocation electrical conductivity of synthetic diamond films

    SciTech Connect

    Samsonenko, S. N. Samsonenko, N. D.

    2009-05-15

    A relationship between the electric resistance of single-crystal homoepitaxial and polycrystalline diamond films and their internal structure has been investigated. It is established that the electrical conductivity of undoped homoepitaxial and polycrystalline diamond films is directly related to the dislocation density in them. A relation linking the resistivity {rho} ({approx}10{sup 13}-10{sup 15} {omega} cm) with the dislocation density {gamma} ({approx}10{sup 14}-4 x 10{sup 16} m{sup -2}) is obtained. The character of this correlation is similar for both groups of homoepitaxial and polycrystalline diamond films. Thin ({approx}1-8 {mu}m) homoepitaxial and polycrystalline diamond films with small-angle dislocation boundaries between mosaic blocks exhibit dislocation conductivity. The activation energy of dislocation acceptor centers was calculated from the temperature dependence of the conductivity and was found to be {approx}0.3 eV. The conduction of thick diamond films (h > 10 {mu}m) with the resistivity {rho} {approx} 10{sup 8} {omega} cm is determined by the conduction of intercrystallite boundaries, which have a nondiamond hydrogenated structure. The electronic properties of the diamond films are compared with those of natural semiconductor diamonds of types IIb and Ic, in which dislocation acceptor centers have activation energies in the range 0.2-0.35 eV and are responsible for hole conduction.

  6. Dislocation motion in solid hcp 3He

    NASA Astrophysics Data System (ADS)

    Beamish, John; Cheng, Zhi Gang

    At temperatures above about 100 mK, dislocations reduce the shear modulus of hcp 4He by as much as 90 %. This occurs when dislocations thermally unbind from the 3He impurities that pin them, becoming extraordinarily mobile. The elastic softening is accompanied by a thermally activated dissipation peak due to the 3He impurities. At higher temperatures the dissipation has an ωT4 dependence caused by scattering of thermal phonons from moving dislocations. Previous measurements on the fermi solid, hcp 3He, showed a similar dislocation softening, but the corresponding dissipation was not measured. We have extended these measurements by measuring the temperature, amplitude and frequency dependence of both the shear modulus and the dissipation in hcp 3He. The dissipation behavior is very different from that of hcp 4He. Neither the impurity unbinding peak associated with the elastic softening, nor the high temperature phonon scattering dissipation, were observed. Instead, there is a large and non-thermally activated dissipation which is largest at low frequencies. We believe that this unexpected dissipation is associated with a new dislocation damping mechanism in 3He, perhaps associated with spin rearrangements caused by moving dislocations. This work was supported by a grant from NSERC Canada.

  7. Isolated dorsal dislocation of the lunate.

    PubMed

    Siddiqui, Na; Sarkar, Sp

    2012-01-01

    Lunate dislocations are well described in the volar direction as part of the perilunate dislocation, sometimes together with fractures of the other carpal bones or distal radius, as described by the anatomical studies of Mayfield [1]. It is a result of disruption of the complex inter-carpal and radiocarpal ligaments that hold the well conforming carpus in their normal position. Given the strength of these structures a significant trauma is required to cause them to fail.However, we present a case of a patient who not only presented with relatively trivial trauma that resulted in a lunate dislocation, but it was also in the dorsal direction and not associated with any fracture or neurological compromise. In addition, she presented several days after her injury.We treated her with closed manipulation and percutaneous K-wire fixation followed by a short period of immobilisation in a Plaster-of-Paris cast, with rapid return to full duties at work.As many volar lunate dislocations may be missed at presentation, we suggest that in patients with relatively trivial trauma there should also be a suspicion of the lunate dislocating dorsally, which may be treated successfully without the aggressive open surgery usually required in volar perilunate dislocations. PMID:23248723

  8. Traumatic posterior dislocation of hip in children.

    PubMed

    Kutty, S; Thornes, B; Curtin, W A; Gilmore, M F

    2001-02-01

    Traumatic posterior dislocation of the hip joint in children is an uncommon injury. It constitutes a true orthopedic emergency. It makes up over 80% of pediatric hip dislocations. In children, it can occur as a result of minimal trauma, which is attributed to a soft pliable acetabulum and ligamentous laxity. In skeletally mature adolescents, a greater force is required to dislocate the hip joint. Delay in reduction is associated with long-term complications such as avascular necrosis and degenerative arthritis. Avascular necrosis is related to the duration of dislocation. A poorer prognosis is associated with delay in reduction beyond 6 hours, advanced skeletal maturity, or multiple traumas. Prompt reduction minimizes complications. We report two cases of traumatic posterior dislocation of hip in children aged 3 and 14 years. Both were reduced within 6 hours of dislocation, and review at 6 months revealed normal examination and no evidence of any post-traumatic changes. Post-reduction treatment remains without a consensus. This review highlights the clinical presentation, management, and time-sensitive complications of the injury. PMID:11265904

  9. Dislocation creep of fine-grained olivine

    NASA Astrophysics Data System (ADS)

    Faul, U. H.; Fitz Gerald, J. D.; Farla, R. J. M.; Ahlefeldt, R.; Jackson, I.

    2011-01-01

    Deformation experiments conducted in a gas medium apparatus at temperatures from 1200 to 1350°C with a fine-grained, solution-gelation derived Fe-bearing olivine show a stress dependence of the strain rate at stresses above ˜150 MPa, which is much stronger than previously reported for polycrystalline samples. The data can be fit by a power law with ??σn with n ˜ 7-8, or equally well by a Peierls creep law with exponential stress dependence. Due to the observed strong stress dependence the samples deform at significantly higher strain rates at a given stress than single crystals or coarse-grained polycrystals with n ˜ 3.5. TEM observations indicate the presence of dislocations with at least two different Burgers vectors, with free dislocations predominantly of screw character. Subgrain walls are present but are only weakly developed and have small misorientation angles. Both the rheology and dislocation structures are consistent with creep rate-limited by dislocation glide or cross slip for aggregates with grain sizes smaller than or approaching the recrystallized grain size. Deformation mechanism maps extrapolated to lithospheric temperatures using the melt-free diffusion creep rheology of Faul and Jackson (2007), the dislocation creep rheology of Hirth and Kohlstedt (2003), and the results described here indicate that deformation conditions of ultramylonitic shear zones fall near the triple point of Peierls, dislocation, and diffusion creep.

  10. Generalized dynamics of moving dislocations in quasicrystals

    NASA Astrophysics Data System (ADS)

    Agiasofitou, Eleni; Lazar, Markus; Kirchner, Helmut

    2010-12-01

    A theoretical framework for dislocation dynamics in quasicrystals is provided according to the continuum theory of dislocations. Firstly, we present the fundamental theory for moving dislocations in quasicrystals giving the dislocation density tensors and introducing the dislocation current tensors for the phonon and phason fields, including the Bianchi identities. Next, we give the equations of motion for the incompatible elastodynamics as well as for the incompatible elasto-hydrodynamics of quasicrystals. We continue with the derivation of the balance law of pseudomomentum thereby obtaining the generalized forms of the Eshelby stress tensor, the pseudomomentum vector, the dynamical Peach-Koehler force density and the Cherepanov force density for quasicrystals. The form of the dynamical Peach-Koehler force for a straight dislocation is obtained as well. Moreover, we deduce the balance law of energy that gives rise to the generalized forms of the field intensity vector and the elastic power density of quasicrystals. The above balance laws are produced for both models. The differences between the two models and their consequences are revealed. The influences of the phason fields as well as of the dynamical terms are also discussed.

  11. Generalized dynamics of moving dislocations in quasicrystals.

    PubMed

    Agiasofitou, Eleni; Lazar, Markus; Kirchner, Helmut

    2010-12-15

    A theoretical framework for dislocation dynamics in quasicrystals is provided according to the continuum theory of dislocations. Firstly, we present the fundamental theory for moving dislocations in quasicrystals giving the dislocation density tensors and introducing the dislocation current tensors for the phonon and phason fields, including the Bianchi identities. Next, we give the equations of motion for the incompatible elastodynamics as well as for the incompatible elasto-hydrodynamics of quasicrystals. We continue with the derivation of the balance law of pseudomomentum thereby obtaining the generalized forms of the Eshelby stress tensor, the pseudomomentum vector, the dynamical Peach-Koehler force density and the Cherepanov force density for quasicrystals. The form of the dynamical Peach-Koehler force for a straight dislocation is obtained as well. Moreover, we deduce the balance law of energy that gives rise to the generalized forms of the field intensity vector and the elastic power density of quasicrystals. The above balance laws are produced for both models. The differences between the two models and their consequences are revealed. The influences of the phason fields as well as of the dynamical terms are also discussed. PMID:21406784

  12. 20 CFR 663.440 - What are the requirements for consumer choice?

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... LABOR (CONTINUED) ADULT AND DISLOCATED WORKER ACTIVITIES UNDER TITLE I OF THE WORKFORCE INVESTMENT ACT... individual with an ITA to a training provider is paid by the applicable adult or dislocated worker...

  13. 20 CFR 663.410 - What is an Individual Training Account (ITA)?

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... LABOR (CONTINUED) ADULT AND DISLOCATED WORKER ACTIVITIES UNDER TITLE I OF THE WORKFORCE INVESTMENT ACT... on behalf of a participant. WIA title I adult and dislocated workers purchase training services...

  14. 20 CFR 663.500 - What is the purpose of this subpart?

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...) ADULT AND DISLOCATED WORKER ACTIVITIES UNDER TITLE I OF THE WORKFORCE INVESTMENT ACT Eligible Training... train adults and dislocated workers. In order to maximize customer choice and assure that...

  15. Factors Affecting Participation of Displaced Workers in Retraining: A Literature Review.

    ERIC Educational Resources Information Center

    Dean, Gary J.

    This document offers a selected review of literature relevant to retraining displaced workers. A description of the economic conditions leading to the displacement of workers, the nature and scope of the displaced worker problem, and factors potentially affecting displaced workers' participation in adult education and training programs is…

  16. What Kind of Adult Literacy Policy Do We Need If We Are Serious about Enabling Every Adult To Become a High Skills/High Wage Worker in the Global Economy?

    ERIC Educational Resources Information Center

    National Inst. for Literacy, Washington, DC.

    The current pressure to look seriously at the connection between the economy and the educational and occupational skills of adults is being driven by changes in both economic conditions and the makeup of the U.S. labor force. Manufacturing has declined, taking with it low-skill, high-wage jobs, and the work force has more immigrants, women, and…

  17. Un trait du francais parle authentique: La dislocation. (A Trait of Authentic Spoken French: Dislocation.)

    ERIC Educational Resources Information Center

    Calve, Pierre

    1983-01-01

    The dislocation of sentence elements in spoken French is seen as allowing the speaker to free himself from certain constraints imposed on word order, position of accents, and grammar. Dislocation is described, its various functions are enumerated, and implications for second language instruction are outlined. (MSE)

  18. Advances in the theory of the Hall-Petch relation, dislocation pileups and dislocation sources

    NASA Astrophysics Data System (ADS)

    Friedman, Lawrence Henry

    Advances in the theory of dislocations are reported. The Hall-Petch relation is extended, and a continuum level simulation of curvilinear dislocations is developed and used to study the operation of Frank-Read sources. The Hall-Petch relation states that the yield stress, sigma y, or strength against plastic deformation of polycrystalline materials is enhanced by decreasing the grain diameter: sigma y = Kd--1/2 + sigma 0, with K and sigma0 constants. One explanation of this relation is that yielding results from stress concentrated by queues of dislocations known as pileups. The pileup theory of the Hall-Petch relation is extended in two ways. First, two important aspects of pileup formation are incorporated into the theory: the existence of a threshold stress for dislocation production and the necessity of a finite-sized dislocation-free region in which a dislocation source may operate. Using a continuum theory of dislocation pileups, a closed form expression is obtained for the dependence of yield stress on grain size and source characteristics. The continuum model agrees closely with the corresponding discrete dislocation model. Second, a scaling theory describing the strength of lamellar materials is developed. The Hall-Petch relation is found to result from the similarity between dislocation densities of pileups of different lengths and under different applied stresses. For multilayers, the scaling theory predicts sigma y = KΛ--a + sigma0, where Λ is the compositional wavelength of the multilayer and a is a material dependent exponent. The scaling theory is then enlarged to incorporate parameters important to the operation of dislocation sources. The simulation of curvilinear dislocations, based on linear isotropic elasticity theory, includes self stress and dislocation-dislocation interactions. The operation stress of a Frank-Read source is found as a function of source size. Additionally, the plastic strain produced by a continuously operating source was

  19. Dislocation dynamics in multiwalled carbon nanotubes at high temperatures.

    PubMed

    Huang, J Y; Ding, F; Yakobson, B I

    2008-01-25

    Dislocation dynamics dictate the mechanical behavior of materials. Dislocations in periodic crystalline materials have been well documented. On the contrary, dislocations in cylindrical carbon nanotubes, particularly in multiwalled carbon nanotubes (MWCNTs), remain almost unexplored. Here we report that a room temperature 1/2<0001> sessile dislocation in a MWCNT becomes highly mobile, as characterized by its glide, climb, and the glide-climb interactions, at temperatures of about 2000 degrees C. The dislocation glide leads to the cross-linking of different shells; dislocation climb creates nanocracks; and the interaction of two 1/2<0001> dislocations creates kinks. We found that dislocation loops act as channels for mass transport. These dislocation dynamics are drastically different from that in conventional periodic crystalline materials due to the cylindrical, highly anisotropic structures of MWCNTs. PMID:18232998

  20. Bauschinger effect in thin metal films: Discrete dislocation dynamics study

    NASA Astrophysics Data System (ADS)

    Davoudi, Kamyar M.; Nicola, Lucia; Vlassak, Joost J.

    2014-01-01

    The effects of dislocation climb on plastic deformation during loading and unloading are studied using a two-dimensional discrete dislocation dynamics model. Simulations are performed for polycrystalline thin films passivated on both surfaces. Dislocation climb lowers the overall level of the stress inside thin films and reduces the work hardening rate. Climb decreases the density of dislocations in pile-ups and reduces back stresses. These factors result in a smaller Bauschinger effect on unloading compared to simulations without climb. As dislocations continue to climb at the onset of unloading and the dislocation density continues to increase, the initial unloading slope increases with decreasing unloading rate. Because climb disperses dislocations, fewer dislocations are annihilated during unloading, leading to a higher dislocation density at the end of the unloading step.

  1. Influence of dislocation and dislocation loop biases on microstructures simulated by rate equation cluster dynamics

    NASA Astrophysics Data System (ADS)

    Jourdan, T.

    2015-12-01

    Sensitivity of microstructures under irradiation to absorption biases of dislocations and dislocation loops is investigated by rate equation cluster dynamics (RECD). Contrary to standard rate theory which is often used to estimate sensitivity of cavity growth to biases, it is possible with RECD to quantify the effect of biases on nucleation, growth and coarsening of loops and cavities. For this purpose simple and accurate expressions for dislocation and dislocation loop biases are derived, based on finite element calculations. They are used in a RECD code to quantify the effect of biases on microstructures of austenitic steels irradiated with electrons. It is shown that biases have a strong influence not only on the loop and dislocation network evolutions, but also on cavity nucleation. Sensitivity to some other parameters of the model is also discussed.

  2. The Foreign Workers and Foreign Workers' German.

    ERIC Educational Resources Information Center

    Blackshire-Belay, Carol

    Foreign Workers' German (FWG) refers to the acquired German language skills of workers from various countries who were recruited to West Germany between 1955 and 1973 to fill menial, undesirable jobs. Contact between these workers and native German speakers was limited because of the nature of the foreigners' work, the tendency toward residential…

  3. Screw dislocations in GaN

    SciTech Connect

    Liliental-Weber, Zuzanna; Jasinski, Jacek B.; Washburn, Jack; O'Keefe, Michael A.

    2002-02-15

    GaN has received much attention over the past few years because of several new applications, including light emitting diodes, blue laser diodes and high-power microwave transistors. One of the biggest problems is a high density of structural defects, mostly dislocations, due to a lack of a suitable lattice-matched substrate since bulk GaN is difficult to grow in large sizes. Transmission Electron Microscopy (TEM) has been applied to study defects in plan-view and cross-sections on samples prepared by conventional techniques such as mechanical thinning and precision ion milling. The density of dislocations close to the sample surface of a 1 mm-thick HVPE sample was in the range of 3x109 cm-2. All three types of dislocations were present in these samples, and almost 50 percent were screw dislocations. Our studies suggest that the core structure of screw dislocations in the same material might differ when the material is grown by different methods.

  4. Glassy dislocation dynamics in colloidal dimer crystals

    NASA Astrophysics Data System (ADS)

    Gerbode, Sharon

    2012-02-01

    Dislocation mobility is central to both the mechanical response and the relaxation mechanisms of crystalline materials. Recent experiments have explored the role of novel particle anisotropies in affecting the rules of defect motion in crystals. ``Peanut-shaped'' colloidal dimer particles consisting of two connected spherical lobes form densely packed crystals in 2D. In these ``degenerate crystals,'' the particle lobes occupy triangular lattice sites while the particle axes are randomly oriented among the three crystalline directions. One consequence of the random orientations of the dimers is that dislocation glide is severely limited by certain particle arrangements in the degenerate crystals. Using optical tweezers to manipulate single lobe-sized spherical intruder particles, we locally deform the crystal, creating defects. During subsequent relaxation, the dislocations formed during the deformation leave the crystal grain, either via annihilation with other dislocations or by moving to a grain boundary. Interestingly, in large crystalline grains this dislocation relaxation occurs through a two-stage process reminiscent of slow relaxations in glassy systems, suggesting the novel concept that glassy phenomena may be introduced to certain kinds of colloidal crystals via simple anisotropic constituents.

  5. Isolated dorsal dislocation of the tarsal naviculum

    PubMed Central

    Hamdi, Kaziz; Hazem, Ben Ghozlen; Yadh, Zitoun; Faouzi, Abid

    2015-01-01

    Isolated dislocation of the tarsal naviculum is an unusual injury, scarcely reported in the literature. The naviculum is surrounded by the rigid bony and ligamentous support hence fracture dislocation is more common than isolated dislocation. The mechanism and treatment options remain unclear. In this case report, we describe a 31 year old man who sustained an isolated dorsal dislocation of the left tarsal naviculum, without fracture, when he was involved in a motor vehicle collision. The reported mechanism of the dislocation is a hyper plantar flexion force applied to the midfoot, resulting in a transient disruption of the ligamentous support of the naviculum bone, with dorsal displacement of the bone. The patient was treated with open reduction and Krischner-wire fixation of the navicular after the failure of closed reduction. The wires were removed after 6 weeks postoperatively. Physiotherapy for stiffness and midfoot pain was recommended for 2 months. At 6 months postoperatively, limping, midfoot pain and weakness were reported, no X-ray abnormalities were found. The patient returned to his obvious activities with a normal range of motion. PMID:26806978

  6. Dislocation dynamics in an anisotropic stripe pattern.

    PubMed

    Kamaga, Carina; Ibrahim, Fatima; Dennin, Michael

    2004-06-01

    The dynamics of dislocations confined to grain boundaries in a striped system are studied using electroconvection in the nematic liquid crystal N4. In electroconvection, a striped pattern of convection rolls forms for sufficiently high driving voltages. We consider the case of a rapid change in the voltage that takes the system from a uniform state to a state consisting of striped domains with two different wave vectors. The domains are separated by domain walls along one axis and a grain boundary of dislocations in the perpendicular direction. The pattern evolves through dislocation motion parallel to the domain walls. We report on features of the dislocation dynamics. The kinetics of the domain motion is quantified using three measures: dislocation density, average domain wall length, and total domain wall length per area. All three quantities exhibit behavior consistent with power-law evolution in time, with the defect density decaying as t(-1/3), the average domain wall length growing as t(1/3), and the total domain wall length decaying as t(-1/5). The two different exponents are indicative of the anisotropic growth of domains in the system. PMID:15244714

  7. Crack interaction with 3-D dislocation loops

    NASA Astrophysics Data System (ADS)

    Gao, Huajian

    CRACKS in a solid often interact with other crystal defects such as dislocation loops. The interaction effects are of 3-D character yet their analytical treatment has been mostly limited to the 2-D regime due to mathematical complications. This paper shows that distribution of the stress intensity factors along a crack front due to arbitrary dislocation loops may be expressed as simple line integrals along the loop contours. The method of analysis is based on the 3-D Bueckner-Rice weight function theory for elastic crack analysis. Our results have significantly simplified the calculations for 3-D dislocation loops produced in the plastic processes at the crack front due to highly concentrated crack tip stress fields. Examples for crack-tip 3-D loops and 2-D straight dislocations emerging from the crack tip are given to demonstrate applications of the derived formulae. The results are consistent with some previous analytical solutions existing in the literature. As further applications we also analyse straight dislocations that are parallel or perpendicular to the crack plane but are not parallel to the crack front.

  8. Search for dislocation free 4He crystals

    NASA Astrophysics Data System (ADS)

    Souris, Fabien; Fefferman, Andrew; Haziot, Ariel; Beamish, John; Balibar, Sebastien

    2014-03-01

    The elastic anomaly of 4He crystals is known to be a consequence of the motion of their dislocations. We have built an acoustic cell in order to grow and study crystals with the smallest possible density of dislocations. It has a polished inner surface to avoid pinning sites for the liquid-solid interface. Piezoelectric transducers are placed outside the cell volume, in order to drive and detect acoustical resonances through built-in copper membranes. We expect dislocation free crystals to behave rather differently from the usual ones (1,2). For example, they should not show any anomalous softening. Preliminary results show that crystals grown in this particular cell have longer dislocation lengths than in those studied in previous experiments (1,2). Centimeter long dislocations should resonate below 20 kHz. 1- A. Haziot et al., Phys. Rev. Lett. 110, 035301 (2013), Phys. Rev. B 87, 060509(R) (2013), and Phys. Rev. B 88, 014106 (2013). 2- A. D. Fefferman et al., submitted to Phys. Rev. B, Nov. 2013. ERC Grant AdG247258 SUPERSOLID and NSERC Canada.

  9. High dislocation density of tin induced by electric current

    SciTech Connect

    Liao, Yi-Han; Liang, Chien-Lung; Lin, Kwang-Lung; Wu, Albert T.

    2015-12-15

    A dislocation density of as high as 10{sup 17} /m{sup 2} in a tin strip, as revealed by high resolution transmission electron microscope, was induced by current stressing at 6.5 x 10{sup 3} A/ cm{sup 2}. The dislocations exist in terms of dislocation line, dislocation loop, and dislocation aggregates. Electron Backscattered Diffraction images reflect that the high dislocation density induced the formation of low deflection angle subgrains, high deflection angle Widmanstätten grains, and recrystallization. The recrystallization gave rise to grain refining.

  10. 20 CFR 663.220 - Who may receive intensive services?

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...) ADULT AND DISLOCATED WORKER ACTIVITIES UNDER TITLE I OF THE WORKFORCE INVESTMENT ACT Intensive Services § 663.220 Who may receive intensive services? There are two categories of adults and dislocated workers who may receive intensive services: (a) Adults and dislocated workers who are unemployed,...

  11. 20 CFR 663.220 - Who may receive intensive services?

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...) ADULT AND DISLOCATED WORKER ACTIVITIES UNDER TITLE I OF THE WORKFORCE INVESTMENT ACT Intensive Services § 663.220 Who may receive intensive services? There are two categories of adults and dislocated workers who may receive intensive services: (a) Adults and dislocated workers who are unemployed,...

  12. Adult Education in Germany.

    ERIC Educational Resources Information Center

    Huddleston, John

    This study is limited essentially to adult education in West Germany, although the historical sections include references to earlier experiences and experiments in areas now Russian-occupied. The terms "adult edcuation" and "workers' education" are clarified. Both are presented as separate movements. Brief reference is made to political, social,…

  13. Electron paramagnetic resonance at dislocations in germanium

    SciTech Connect

    Pakulis, E.J.

    1982-06-01

    The first observation of the paramagnetic resonance of electrons at dislocations in germanium single crystals is reported. Under subband gap optical excitation, two sets of lines are detected: four lines about the <111> axes with g/sub perpendicular to/ = 0.34 and g/sub parallel/ = 1.94, and 24 lines with g/sub perpendicular to/ = 0.73 and g/sub parallel/ = 1.89 about <111> axes with the six-fold 1.2/sup 0/ distortion. This represents the first measurement of the disortion angle of a dislocation dangling bond. The possibility that the distortion results from a Peierls transition along the dislocation line is discussed.

  14. Crack Tip Dislocation Nucleation in FCC Solids

    NASA Astrophysics Data System (ADS)

    Knap, J.; Sieradzki, K.

    1999-02-01

    We present results of molecular dynamic simulations aimed at examining crack tip dislocation emission in fcc solids. The results are analyzed in terms of recent continuum formulations of this problem. In mode II, Au, Pd, and Pt displayed a new unanticipated mechanism of crack tip dislocation emission involving the creation of a pair of Shockley partials on a slip plane one plane below the crack plane. In mode I, for all the materials examined, Rice's continuum formulation [J. Mech. Phys. Solids 40, 239 (1992)] underestimated the stress intensity for dislocation emission by almost a factor of 2. Surface stress corrections to the emission criterion brought the agreement between continuum predictions and simulations to within 20%.

  15. Brachial Artery Injury Accompanying Closed Elbow Dislocations

    PubMed Central

    Harnarayan, Patrick; Cawich, Shamir O.; Harnanan, Dave; Budhooram, Steve

    2014-01-01

    Introduction Brachial artery injuries from elbow dislocations are uncommon, but they may lead to disastrous consequences if the diagnosis is delayed. Presentation of case We report a case of a patient who sustained a fall onto the elbow, with dislocation and brachial artery injury, despite an ipsilateral radial pulse being palpable. Discussion Clinicians should maintain a high index of suspicion for brachial injury when patients present with a fall onto the elbow coupled with signs suggestive of fracture-dislocation, nerve injury and/or signs of limb ischemia. Frank ischamia, however, is uncommon as there is a rich collateral anastomosis in the upper limb. Conclusion A high index of suspicion should be maintained in order to make the diagnosis early. Exploration with excision of the injured segment and reverse vein interposition grafting is the treatment of choice in these cases. PMID:25644552

  16. A preliminary investigation of dislocation cell structure formation in metals using continuum dislocation dynamics

    NASA Astrophysics Data System (ADS)

    Xia, S. X.; El-Azab, A.

    2015-08-01

    A continuum dislocation dynamics model capable of capturing the cellular arrangements of dislocations in deformed crystals is presented. A small strain formulation of the model is given, followed by sample results of stress-strain behaviour, dislocation density evolution, dislocation cell pattern, lattice rotation, and geometrically necessary dislocation density and strain energy density distributions. An important finding of the current work is that dislocations form patterns under all circumstances due to their long range interactions. It is found, however, that the famous cell structure pattern forms when cross slip is activated. It is also found that cells are 3D sub-regions surrounded by dislocations walls in all directions, and they form, disappear, and reappear as a result of the motion of cell walls and formation of new walls by cross slip. It is further found that the average cell size is connected with the applied resolved shear stress according to the similitude principle observed in related experiments. The importance of these results is briefly discussed in the context of recrystallization.

  17. Dislocation dynamics in SiGe alloys

    NASA Astrophysics Data System (ADS)

    Yonenaga, I.

    2013-11-01

    The dislocation velocities and mechanical strength of bulk crystals of SixGe1-x alloys grown by the Czochralski method have been investigated by the etch pit technique and compressive deformation tests, respectively. Velocity of dislocations in the SiGe alloys of the composition range 0.004 < x < 0.08 decreases monotonically with an increase in Si content at temperature 450-700°C and under stress 3-24MPa. In contrast, velocity of dislocations in the composition range 0.92 < x < 1 first increases, then decreases and again increases with a decrease in Si content at temperature 750-850°C and under stress 3-30MPa. The velocity of dislocations was quantitatively evaluated as functions of stress and temperature. Stress-strain behaviour in the yield region of the SiGe alloys of composition 0 < x < 0.4 is similar to that of Ge at temperatures lower than about 600°C. However, the yield stress becomes temperature-insensitive at high temperatures and increases with increasing Si content. The stress-strain curves of the SiGe alloys of composition 0.95 < x < 1 are similar to those of pure Si at temperatures 800-1000°C and the yield stress increases with decreasing Si content down to x = 0.95. The yield stress of the SiGe alloys is dependent on the composition, being proportional to x(1-x), showing a maximum around x ≈ 0.5. Built-in stress fields related to local fluctuation of the alloy composition and the dynamic development of a solute atmosphere around the dislocations, may suppress the activities of dislocations and lead to the hardening of SiGe alloys.

  18. High-temperature discrete dislocation plasticity

    NASA Astrophysics Data System (ADS)

    Keralavarma, S. M.; Benzerga, A. A.

    2015-09-01

    A framework for solving problems of dislocation-mediated plasticity coupled with point-defect diffusion is presented. The dislocations are modeled as line singularities embedded in a linear elastic medium while the point defects are represented by a concentration field as in continuum diffusion theory. Plastic flow arises due to the collective motion of a large number of dislocations. Both conservative (glide) and nonconservative (diffusion-mediated climb) motions are accounted for. Time scale separation is contingent upon the existence of quasi-equilibrium dislocation configurations. A variational principle is used to derive the coupled governing equations for point-defect diffusion and dislocation climb. Superposition is used to obtain the mechanical fields in terms of the infinite-medium discrete dislocation fields and an image field that enforces the boundary conditions while the point-defect concentration is obtained by solving the stress-dependent diffusion equations on the same finite-element grid. Core-level boundary conditions for the concentration field are avoided by invoking an approximate, yet robust kinetic law. Aspects of the formulation are general but its implementation in a simple plane strain model enables the modeling of high-temperature phenomena such as creep, recovery and relaxation in crystalline materials. With emphasis laid on lattice vacancies, the creep response of planar single crystals in simple tension emerges as a natural outcome in the simulations. A large number of boundary-value problem solutions are obtained which depict transitions from diffusional to power-law creep, in keeping with long-standing phenomenological theories of creep. In addition, some unique experimental aspects of creep in small scale specimens are also reproduced in the simulations.

  19. Geometry of dislocated de Broglie waves

    SciTech Connect

    Holland, P.R.

    1987-04-01

    The geometrical structures implicit in the de Broglie waves associated with a relativistic charged scalar quantum mechanical particle in an external field are analyzed by employing the ray concept of the causal interpretation. It is shown how an osculating Finslerian metric tensor, a torsion tensor, and a tetrad field define respectively the strain, the dislocation density, and the Burgers vector in the natural state of the wave, which is a non-Riemannian space of distant parallelism. A quantum torque determined by the quantum potential is introduced and the example of a screw dislocated wave is discussed.

  20. Suppressing dislocations in normalized hypercubic smearing

    NASA Astrophysics Data System (ADS)

    DeGrand, Thomas; Shamir, Yigal; Svetitsky, Benjamin

    2014-09-01

    Normalized hypercubic smearing improves the behavior of dynamical Wilson-clover fermions, but has the unwanted side effect that it can occasionally produce spikes in the fermion force. These spikes originate in the chain rule connecting the derivative with respect to the smeared links to the derivative with respect to the dynamical links, and are associated with the presence of dislocations in the dynamical gauge field. We propose and study an action designed to suppress these dislocations. We present evidence for improved performance of the hybrid Monte Carlo algorithm. A side benefit is improvement in the properties of valence chiral fermions.

  1. Formation and structure of misfit dislocations

    NASA Astrophysics Data System (ADS)

    Nandedkar, A. S.; Srinivasan, G. R.; Murthy, C. S.

    1991-03-01

    We report here theoretical observations of the evolution of core structure of well-defined misfit dislocations arising from the spontaneous decomposition of highly strained coherent interfaces in a fcc bicrystal. We use a finely stepped energy-minimization technique and Lennard-Jones pair potential, which allowed Burgers-circuit construction and core-structure analysis. Simulations were made for (111) and (001) interfaces, which produced 60° and edge dislocations, respectively. The atomic configurations produced were consistent with those expected from the elasticity theory.

  2. Rotator Cuff Tear Consequent to Glenohumeral Dislocation.

    PubMed

    Gilotra, Mohit N; Christian, Matthew W; Lovering, Richard M

    2016-08-01

    The patient was a 21-year-old collegiate running back who was tackled during a football game and sustained a posterior glenohumeral dislocation. He was referred to an orthopaedist and presented 3 weeks after the injury, and, following examination, further imaging was ordered by the orthopaedist due to rotator cuff weakness. Magnetic resonance imaging showed a complete tear of the supraspinatus and infraspinatus, as well as a posterior Bankart lesion, a subscapularis tear, and a dislocation of the biceps long head tendon into the reverse Hill-Sachs lesion. J Orthop Sports Phys Ther 2016;46(8):708. doi:10.2519/jospt.2016.0413. PMID:27477475

  3. Changes in the Burgers Vector of Perfect Dislocation Loops without Contact with the External Dislocations

    SciTech Connect

    Arakawa, K.; Hatanaka, M.; Mori, H.; Kuramoto, E.; Ono, K.

    2006-03-31

    We report the observations of a new type of changing process in the Burgers vector of dislocations by in situ transmission electron microscopy. Small interstitial-type perfect dislocation loops in bcc iron with diameters less than approximately 50 nm are transformed from a 1/2<111> loop to another 1/2<111> one or an energetically unfavorable <100> one; furthermore, a <100> loop is transformed to a 1/2<111> one. These transformations occurred on high-energy electron irradiation or simple heating without contact with external dislocations. The origin of these phenomena is discussed.

  4. A model for nucleation of tin whisker through dislocation behavior

    NASA Astrophysics Data System (ADS)

    Nakai, K.; Sakamoto, T.; Kobayashi, S.; Takamizawa, M.; Murakami, K.; Hino, M.

    2009-05-01

    A model for the nucleation and growth processes of Sn whisker is offered. High density of localized screw dislocations by deformation form the dense spiral steps of atomic scale on Sn surface. The spiral steps would induce the nucleation of Sn whisker. Edge dislocations localized at the same region where dense screw dislocations exist supply Sn atoms to the Sn whisker through pipe diffusion. Both screw and edge dislocations would bend along almost one direction, namely, to relax the external shear stress. The image force also helps to bend the dislocations perpendicular to the whisker side-surface. The bending of dislocations at root of whisker leads the bend of whisker. The pipe diffusion of Sn atoms through edge dislocations from bulk Sn toward whisker is suppressed at the bent part of edge dislocation, resulting in release of Sn atoms inside whisker and leading to the growth of whisker near its root.

  5. Continuum dislocation dynamics: Towards a physical theory of crystal plasticity

    NASA Astrophysics Data System (ADS)

    Hochrainer, Thomas; Sandfeld, Stefan; Zaiser, Michael; Gumbsch, Peter

    2014-02-01

    The plastic deformation of metals is the result of the motion and interaction of dislocations, line defects of the crystalline structure. Continuum models of plasticity, however, remain largely phenomenological to date, usually do not consider dislocation motion, and fail when materials behavior becomes size dependent. In this work we present a novel plasticity theory based on systematic physical averages of the kinematics and dynamics of dislocation systems. We demonstrate that this theory can predict microstructure evolution and size effects in accordance with experiments and discrete dislocation simulations. The theory is based on only four internal variables per slip system and features physical boundary conditions, dislocation pile ups, dislocation curvature, dislocation multiplication and dislocation loss. The presented theory therefore marks a major step towards a physically based theory of crystal plasticity.

  6. Scale-free phase field theory of dislocations.

    PubMed

    Groma, István; Vandrus, Zoltán; Ispánovity, Péter Dusán

    2015-01-01

    According to recent experimental and numerical investigations, if a characteristic length (such as grain size) of a specimen is in the submicron size regime, several new interesting phenomena emerge during the deformation. Since in such systems boundaries play a crucial role, to model the plastic response it is crucial to determine the dislocation distribution near the boundaries. In this Letter, a phase-field-type continuum theory of the time evolution of an ensemble of parallel edge dislocations with identical Burgers vectors, corresponding to the dislocation geometry near internal boundaries, is presented. Since the dislocation-dislocation interaction is scale free (1/r), apart from the average dislocation spacing the theory cannot contain any length scale parameter. As shown, the continuum theory suggested is able to recover the dislocation distribution near boundaries obtained by discrete dislocation dynamics simulations. PMID:25615479

  7. Scale-Free Phase Field Theory of Dislocations

    NASA Astrophysics Data System (ADS)

    Groma, István; Vandrus, Zoltán; Ispánovity, Péter Dusán

    2015-01-01

    According to recent experimental and numerical investigations, if a characteristic length (such as grain size) of a specimen is in the submicron size regime, several new interesting phenomena emerge during the deformation. Since in such systems boundaries play a crucial role, to model the plastic response it is crucial to determine the dislocation distribution near the boundaries. In this Letter, a phase-field-type continuum theory of the time evolution of an ensemble of parallel edge dislocations with identical Burgers vectors, corresponding to the dislocation geometry near internal boundaries, is presented. Since the dislocation-dislocation interaction is scale free (1 /r ), apart from the average dislocation spacing the theory cannot contain any length scale parameter. As shown, the continuum theory suggested is able to recover the dislocation distribution near boundaries obtained by discrete dislocation dynamics simulations.

  8. Molecular dynamics simulations of dislocation instability in a stress gradient

    NASA Astrophysics Data System (ADS)

    Li, Ming; Selinger, Robin L.

    2003-04-01

    We present simulation studies of a morphological instability arising in dislocation dynamics. When an initially straight dislocation line is driven by a stress whose magnitude grows along the direction of dislocation motion, vibrational modes of the dislocation line with wavelength above a threshold value become linearly unstable. Molecular dynamics simulation studies of screw dislocations in Al demonstrate the onset of the instability during dislocation pair annihilation and annihilation at a crack tip. The wavelength of the unstable vibrational mode observed in each case agrees with the predictions of theoretical analysis. We discuss the role of temperature in nucleating the instability and speculate about how instabilities in dislocation motion could affect the density of threading dislocations during growth of heteroepitaxial thin films.

  9. Determination of the inhomogeneous dislocation density in a crystallographic texture

    SciTech Connect

    Satdarova, F. F.; Kozlov, D. A.

    2007-03-15

    Diffraction analysis of the mixed dislocation structure of a polycrystal with an orthorhombic texture is reported. A significant difference in the dislocation densities in the texture components of cold-deformed low-carbon steel has been revealed.

  10. Dislocation dynamics in Rayleigh-Bénard convection.

    PubMed

    Walter, Th; Pesch, W; Bodenschatz, E

    2004-09-01

    Theoretical results on the dynamics of dislocations in Rayleigh-Bénard convection are reported both for a Swift-Hohenberg model and the Oberbeck-Boussinesq equations. For intermediate Prandtl numbers the motion of dislocations is found to be driven by the superposition of two independent contributions: (i) the Peach-Koehler force and (ii) an advection force on the dislocation core by its self-generated mean flow. Their competition allows to explain the experimentally observed bound dislocation pairs. PMID:15447003

  11. Achieving Adult Literacy. Fastback 330.

    ERIC Educational Resources Information Center

    Farris, Pamela J.

    Leaders in business and industry are demanding workers who not only can read and write but can think creatively and critically and solve problems. Federal- and state-funded programs and volunteer organizations are involved with adult literacy. Increasingly, corporations are funding adult literacy projects. Adults read for different reasons than…

  12. An Acoustic Profile of Right-Dislocations in French.

    ERIC Educational Resources Information Center

    Ashby, William J.

    1994-01-01

    Provides an acoustic profile of the prosody of right-dislocations in French, using the CECIL computer hardware and software package to analyze 28 right-dislocations occurring in a corpus of natural French discourse. It was found that, although right-dislocations appear to fulfill various functional roles in discourse, no correlation appears…

  13. On onsagers principle, dislocation motion and hydrogen embrittlement

    NASA Technical Reports Server (NTRS)

    Louthan, M. R., Jr.; Mcnitt, R. P.

    1976-01-01

    Onsager's reciprocal relationships from the linear theory of irreversible thermodynamics are applied to hydrogen - dislocation interactions. Existing experimental evidence shows that dislocation motion causes localized hydrogen accumulation; thus, from the Onsager principle, localized hydrogen accumulations will affect dislocation motion and therefore the properties of metals and alloys exposed to hydrogen environments.

  14. Metatarsal Shaft Fracture with Associated Metatarsophalangeal Joint Dislocation.

    PubMed

    Tung, Taranjit Singh

    2016-01-01

    Metatarsophalangeal joint dislocations of lesser toes are often seen in the setting of severe claw toes. Traumatic irreducible dislocations have been reported in rare cases following both low-energy and high-energy injuries to the forefoot. In this case report, I present a previously unreported association of a metatarsal shaft fracture with metatarsophalangeal joint dislocation of a lesser toe. PMID:27597914

  15. Metatarsal Shaft Fracture with Associated Metatarsophalangeal Joint Dislocation

    PubMed Central

    2016-01-01

    Metatarsophalangeal joint dislocations of lesser toes are often seen in the setting of severe claw toes. Traumatic irreducible dislocations have been reported in rare cases following both low-energy and high-energy injuries to the forefoot. In this case report, I present a previously unreported association of a metatarsal shaft fracture with metatarsophalangeal joint dislocation of a lesser toe. PMID:27597914

  16. Dislocation core fields and forces in FCC metals

    SciTech Connect

    Henager, Charles H.; Hoagland, Richard G.

    2004-04-01

    Atomistic models were used to obtain dislocation core fields for edge, screw, and mixed dislocations in Al and Cu using EAM. Core fields are analyzed using a line force dipole representation, with dilatant and dipole terms. The core field contribution to the force between dislocations is shown to be significant for interactions within 50b.

  17. Assessment of hardening due to dislocation loops in bcc iron: Overview and analysis of atomistic simulations for edge dislocations

    NASA Astrophysics Data System (ADS)

    Bonny, G.; Terentyev, D.; Elena, J.; Zinovev, A.; Minov, B.; Zhurkin, E. E.

    2016-05-01

    Upon irradiation, iron based steels used for nuclear applications contain dislocation loops of both < 100 > and ½ < 111 > type. Both types of loops are known to contribute to the radiation hardening and embrittlement of steels. In the literature many molecular dynamics works studying the interaction of dislocations with dislocation loops are available. Recently, based on such studies, a thermo-mechanical model to threat the dislocation - dislocation loop (DL) interaction within a discrete dislocation dynamics framework was developed for ½ < 111 > loops. In this work, we make a literature review of the dislocation - DL interaction in bcc iron. We also perform molecular dynamics simulations to derive the stress-energy function for < 100 > loops. As a result we deliver the function of the activation energy versus activation stress for < 100 > loops that can be applied in a discrete dislocation dynamics framework.

  18. Pilot Study to Determine Accuracy of Posterior Approach Ultrasound for Shoulder Dislocation by Novice Sonographers

    PubMed Central

    Lahham, Shadi; Becker, Brent; Chiem, Alan; Joseph, Linda M.; Anderson, Craig L.; Wilson, Sean P.; Subeh, Mohammad; Trinh, Alex; Viquez, Eric; Fox, John C.

    2016-01-01

    Introduction The goal of this study was to investigate the efficacy of diagnosing shoulder dislocation using a single-view, posterior approach point-of-care ultrasound (POCUS) performed by undergraduate research students, and to establish the range of measured distance that discriminates dislocated shoulder from normal. Methods We enrolled a prospective, convenience sample of adult patients presenting to the emergency department with acute shoulder pain following injury. Patients underwent ultrasonographic evaluation of possible shoulder dislocation comprising a single transverse view of the posterior shoulder and assessment of the relative positioning of the glenoid fossa and the humeral head. The sonographic measurement of the distance between these two anatomic structures was termed the Glenohumeral Separation Distance (GhSD). A positive GhSD represented a posterior position of the glenoid rim relative to the humeral head and a negative GhSD value represented an anterior position of the glenoid rim relative to the humeral head. We compared ultrasound (US) findings to conventional radiography to determine the optimum GhSD cutoff for the diagnosis of shoulder dislocation. Sensitivity, specificity, positive predictive value, and negative predictive value of the derived US method were calculated. Results A total of 84 patients were enrolled and 19 (22.6%) demonstrated shoulder dislocation on conventional radiography, all of which were anterior. All confirmed dislocations had a negative measurement of the GhSD, while all patients with normal anatomic position had GhSD>0. This value represents an optimum GhSD cutoff of 0 for the diagnosis of (anterior) shoulder dislocation. This method demonstrated a sensitivity of 100% (95% CI [82.4–100]), specificity of 100% (95% CI [94.5–100]), positive predictive value of 100% (95% CI [82.4–100]), and negative predictive value of 100% (95% CI [94.5–100]). Conclusion Our study suggests that a single, posterior

  19. Left Dislocation in Near-Native French

    ERIC Educational Resources Information Center

    Donaldson, Bryan

    2011-01-01

    The present study is concerned with the upper limits of SLA--specifically, mastery of the syntax-discourse interface in successful endstate learners of second-language (L2) French (near-native speakers). Left dislocation (LD) is a syntactic means of structuring spoken French discourse by marking topic. Its use requires speakers to coordinate…

  20. Computer simulation of screw dislocation in aluminum

    NASA Technical Reports Server (NTRS)

    Esterling, D. M.

    1976-01-01

    The atomic structure in a 110 screw dislocation core for aluminum is obtained by computer simulation. The lattice statics technique is employed since it entails no artificially imposed elastic boundary around the defect. The interatomic potential has no adjustable parameters and was derived from pseudopotential theory. The resulting atomic displacements were allowed to relax in all three dimensions.

  1. Dislocations - Multiple Languages: MedlinePlus

    MedlinePlus

    ... XYZ List of All Topics All Dislocations - Multiple Languages To use the sharing features on this page, please enable JavaScript. Arabic (العربية) French (français) Russian (Русский) Somali (af Soomaali) ...

  2. Traumatic proximal tibiofibular dislocation with neurovascular injury

    PubMed Central

    Veerappa, Lokesh A; Gopalakrishna, Chetan

    2012-01-01

    23 years old male presented with inferolateral dislocation of proximal tibiofibular joint associated with popliteal artery and common peroneal nerve injury. The extension of the injury to involve the interosseus membrane up to the distal tibiofibular joint. The association of popliteal artery injury is not reported before to the best of our knowledge. PMID:23162155

  3. [Open total dislocation of the talus].

    PubMed

    Grabski, R S; Sosiński, R

    1992-01-01

    A case of 35 years old patient with open, total, fixed dislocation of the talus reduced with heel traction is presented. The Sudeck syndrome subsided after one year. Weight bearing was not allowed for 7 months. An examination after 2.5 years revealed minor osteoarthritis, full range of movement in the foot but limited walking capability. PMID:7555299

  4. An unusual variant of perilunate fracture dislocations

    PubMed Central

    Morin, Matthew L.; Becker, Giles W.

    2016-01-01

    Abstract Trans-scaphoid, trans-radial styloid, trans-triquetral perilunate fracture dislocations are rare. We describe a 19-year-old male who suffered this injury after crashing his bicycle. He underwent open reduction internal fixation and percutaneous pinning. Scaphoid union was achieved at 8 weeks. Near complete range of painless motion was achieved by 4 months.

  5. An unusual variant of perilunate fracture dislocations.

    PubMed

    Morin, Matthew L; Becker, Giles W

    2016-01-01

    Trans-scaphoid, trans-radial styloid, trans-triquetral perilunate fracture dislocations are rare. We describe a 19-year-old male who suffered this injury after crashing his bicycle. He underwent open reduction internal fixation and percutaneous pinning. Scaphoid union was achieved at 8 weeks. Near complete range of painless motion was achieved by 4 months. PMID:27583261

  6. Sociocultural Dislocation: Beyond the Dual Perspective.

    ERIC Educational Resources Information Center

    De Hoyos, Genevieve; And Others

    1986-01-01

    Moves beyond the dual perspective model and beyond medical and ecological systems models to suggest a sociocultural approach and presents a three-stage model for practice with minority clients. Suggests that practice with minorities focus on the degree and kind of dislocation--social, cultural, or sociocultural--suffered by individual clients.…

  7. Copper passivation of dislocations in silicon

    SciTech Connect

    Lee, J.; Morrison, S.R.

    1988-12-15

    The J-V characteristics of metal-insulator-semiconductor solar cells fabricated on Si samples which are damaged (lapped) with 1-..mu..m grit size of Al/sub 2/O/sub 3/ are substantially degraded. The introduction of copper at 250--400 /sup 0/C passivates the dislocations. The copper is diffused in from the surface. Anodic oxidation followed by etching in aqua regia and 48% HF was used to remove excess copper remaining on the damaged surface and to etch away controlled amounts of the silicon wafers. The experimental results are compared to the model of Divigalpitiya and Morrison (J. Appl. Phys. 60, 406 (1986)). It is concluded using the model that copper passivation reduces the product of the density of hole traps and the capture cross section of hole traps and may also increase the specific conductance of the dislocations. Results for samples lapped with finer-grit alumina (0.3 ..mu..m) seem qualitatively different from those with 1-..mu..m alumina. The variation in dislocation density as a function of depth into the surface is used to explain the difference qualitatively. The dislocation density decreases rapidly with distance from the damaged surface.

  8. Temporomandibular joint dislocation: experiences from Zaria, Nigeria

    PubMed Central

    Fomete, Benjamin; Obiadazie, Athanasius Chukwudi; Idehen, Kelvin; Okeke, Uche

    2014-01-01

    Objectives Dislocation of the temporomandibular joint may occur for various reasons. Although different invasive methods have been advocated for its treatment, this study highlights the value of non-invasive treatment options even in chronic cases in a resource-poor environment. Materials and Methods A seven-year retrospective analysis of all patients managed for temporomandibular joint dislocation in our department was undertaken. Patient demographics, risk factors associated with temporomandibular joint dislocation and treatment modalities were retrieved from patient records. Results In all, 26 patients were managed over a seven-year period. Males accounted for 62% of the patients, and yawning was the most frequent etiological factor. Conservative treatment methods were used successfully in 86.4% of the patients managed. Two (66.7%) of the three patients who needed surgical treatment developed complications, while only one (5.3%) patient who was managed conservatively developed complications. Conclusion Temporomandibular joint dislocation appears to be associated with male sex, middle age, yawning, and low socio-economic status, although these observed relationships were not statistically significant. Non-invasive methods remain an effective treatment option in this environment in view of the low socio-economic status of the patients affected. PMID:25045637

  9. Imaging dislocation cores – the way forward

    SciTech Connect

    Spence, John; Kolar, H.R.; Hembree, G; Humphreys, C.J.; Barnard, J.; Datta, R.; Koch, C.; Ross, F.M.; Justo, J.F.

    2006-10-11

    Although the sub-angstrom resolution of the modern transmission electron microscope (TEM) has made major contributions to defect structure analysis in many fields (such as oxides, interfaces, nanoparticles and superconductors) it has yielded little direct information on the core structure of dislocations. We suggest that ‘‘forbidden reflection’’ lattice images recorded in an ultra-high vacuum TEM in projections normal to the dislocation line could provide interpretable images of cores at atomic resolution. These could answer crucial questions, such as the nature of kinks, core reconstruction and periodicity, the nature of obstacles, and help distinguish obstacle theories of kink motion from the secondary Peierls–valley Hirth–Lothe theory. We give experimental forbidden reflection images and a new image obtained from silicon under UHV conditions with atomically smooth surfaces, whose preparation did not anneal out all dislocations. We also show experimental coherent nanodiffraction patterns and scanning transmission electron microscope (STEM) images recorded with the beam parallel to the core, so that core reconstruction can be expected to introduce a ‘‘half-order’’ Laue zone ring. We discuss the contribution that energy-loss spectroscopy from dislocation cores can be expected to make if a nanoprobe beam is used.

  10. Posttraumatic chronic patellar dislocation treated by distal femoral osteotomy and medial patellofemoral ligament reconstruction.

    PubMed

    Purushothaman, Balaji; Agarwal, Amit; Dawson, Matt

    2012-11-01

    Chronic patellar dislocation is a rare condition where the patella remains dislocated throughout knee range of motion during flexion and extension. In adults, the delayed presentation of this condition is often due to symptoms caused by the onset of severe secondary osteoarthritis. To the authors' knowledge, all of the cases reported in the literature have been treated by patellofemoral or total knee replacements depending on patient age and the extent of the arthritis. This article describes a rare case of a 22-year-old woman who sustained a traumatic chronic patellar dislocation for 5 months. Clinical examination revealed a valgus deformity of the left leg secondary to childhood injury and that the patella lay lateral to the lateral femoral condyle throughout flexion and extension. Radiographs of the knee revealed patellar dislocation. Long-leg radiographs of the left leg showed an anatomic tibiofemoral angle of 17° valgus. The anatomical (74°) and mechanical (80°) lateral distal femoral angles were abnormal, whereas the medial proximal tibial angle (87°) was normal, confirming that the valgus deformity was due to the abnormal distal femur. The authors performed a distal femoral osteotomy to correct the valgus deformity. Medial patellofemoral ligament reconstruction using a hamstring autograft was performed to stabilize the patella. PMID:23127463

  11. Treatment of an open medial tibiotalar dislocation with no associated fracture.

    PubMed

    Bhullar, Preetinder S; Grant, Daniel R; Foreman, Mark; Krueger, Chad A

    2014-01-01

    Tibiotalar dislocations without associated fractures are very uncommon in adults, and only a few studies have been published regarding this injury. More than 50% of these dislocations will be posteromedial, with a high incidence of open injuries, and 25% are pure posterior dislocations. In the present report, we discuss our experience and management of a medial tibiotalar dislocation with no associated fracture. In the present case, the patient was brought to the operating room on presentation to our facility and underwent irrigation and debridement with primary closure of his wound. He was immobilized postoperatively. The patient tolerated the operation well and did not sustain any postoperative complications. He was able to regain function of the injured extremity until he was lost to follow-up. Regarding treatment, the surgery should be speedy, gentle to the soft tissue, and with as little implanted material as possible. Although we do not advocate that our management and treatment of this injury become the standard, the present case provides a good example of some of the challenges often encountered when treating these injuries. PMID:25135103

  12. Effects of Dislocations on Minority Carrier Lifetime in Dislocated Float Zone Silicon

    SciTech Connect

    Karoui, A.; Zhang, R.; Rozgonyi, G. A.; Ciszek, T. F.

    2002-08-01

    We present a correlation of Microwave Photoconductance Decay minority carrier lifetime with dislocation density in high purity Float Zone silicon. Electron Beam Induced Current (EBIC) images were carefully aligned to lifetime maps and depth profiling of individual defect electrical activity was done by varying the bias of Schottky diodes. The data presented provides a relationship between lifetime variations and EBIC contrast, based on dislocation density and impurity decoration in the near surface zone.

  13. Elbow dislocation with irreparable fracture radial head

    PubMed Central

    Tanna, Dilip

    2013-01-01

    Background: Treatment of elbow dislocation with irreparable radial head fracture needs replacement of radial head to achieve stability of elbow. An alternate method in cases of elbow dislocation with radial head fracture can be resection of radial head with repair of medial collateral ligament. We report a retrospective analysis of cases of elbow dislocation with irreparable radial head treated by excision head of radius and repair of MCL. Materials and Methods: Nine patients of elbow dislocation with associated irreparable fractures of the head of the radius were included in this analysis (6 F:3 M, Age: 35-47 years). Radial head excision was done through the lateral approach and MCL was sutured using no 3 Ethibond using medial approach. Above elbow plaster was given for 6 weeks and gradual mobilization was done thereafter. All patients were assessed at final followup using Mayo elbow performance score (MEPS). Results: Mean followup was 19.55 ± 7.12 months (range 14-36 months). There was no extension deficit when compared to opposite side with mean range of flexion of 138.8° ± 6.97° (range 130 -145°). Mean pronation was 87.7° ± 4.4° (range 80-90°) and mean supination was 87.7 ± 4.62° (range 80-90°). The mean MEPS was 98.8 ± 3.33 (range 90-100). No patient had pain, sensory complaints, subluxation or redislocation. All were able to carry out their daily activities without disability. Conclusion: Radial head excision with MCL repair is an acceptable option for treatment of patients with elbow dislocation and irreparable radial head fracture. PMID:23798760

  14. Medial Patellofemoral Ligament Reconstruction for Patellar Dislocation

    PubMed Central

    Mackay, Nicola D.; Smith, Nicholas A.; Parsons, Nick; Spalding, Tim; Thompson, Peter; Sprowson, Andrew P.

    2014-01-01

    Background: With improved understanding of the biomechanical importance of the medial patellofemoral ligament (MPFL), its reconstruction for patellar dislocation has become increasingly popular. The aim of this systematic review was to critically determine the effectiveness of MPFL reconstruction for patellar dislocation. Hypothesis: MPFL reconstruction for patellar dislocation leads to a low redislocation rate with improved Kujala scores. Study Design: Systematic review; Level of evidence, 4. Methods: A literature search was performed using Embase and Medline (Ovid) databases. Inclusion criteria included first-time and recurrent patellar dislocation, subluxation, or persistent instability with a minimum follow-up of 12 months and documentation of postoperative redislocation rate or Kujala score. The studies were systematically appraised, and a meta-analysis was performed. Results: Twenty-two studies were included: 2 randomized controlled trials, 3 parallel case series, and 17 case series. There were a total of 655 knees in the review, with an age range at time of surgery from 11 to 52 years. The pooled postoperative redislocation rate from all 17 case series showed a mean of 2.44%. The pooled preoperative Kujala scores from 12 case series showed a mean of 51.6 (95% CI, 46.71-56.49). The pooled postoperative Kujala scores from 16 case series showed a mean of 87.77 (95% CI, 85.15-90.39). Conclusion: Although the studies were of low quality, the meta-analysis of 17 case series shows that MPFL reconstruction for recurrent patellar dislocation results in a significant improvement in Kujala scores, a low redislocation rate, and acceptable complication rate. Randomized trials would be needed to draw influences on the superiority of MPFL reconstruction compared with other treatments. PMID:26535352

  15. Training and Qualifications (Teachers and Workers for the Deaf).

    ERIC Educational Resources Information Center

    World Federation of the Deaf, Rome (Italy).

    Three papers consider the training and qualifications of teachers and workers for the deaf. H. Okopinski describes "Training Teachers for Deaf Children's Schools in Poland" and A. F. Mackenzie defines "The Qualifications of Workers for the Adult Deaf" in the United Kingdom. E. S. Levine reports on New York University's "Center for Research and…

  16. Te homogeneous precipitation in Ge dislocation loop vicinity

    NASA Astrophysics Data System (ADS)

    Perrin Toinin, J.; Portavoce, A.; Texier, M.; Bertoglio, M.; Hoummada, K.

    2016-06-01

    High resolution microscopies were used to study the interactions of Te atoms with Ge dislocation loops, after a standard n-type doping process in Ge. Te atoms neither segregate nor precipitate on dislocation loops, but form Te-Ge clusters at the same depth as dislocation loops, in contradiction with usual dopant behavior and thermodynamic expectations. Atomistic kinetic Monte Carlo simulations show that Te atoms are repulsed from dislocation loops due to elastic interactions, promoting homogeneous Te-Ge nucleation between dislocation loops. This phenomenon is enhanced by coulombic interactions between activated Te2+ or Te1+ ions.

  17. Radiation enhanced basal plane dislocation glide in GaN

    NASA Astrophysics Data System (ADS)

    Yakimov, Eugene B.; Vergeles, Pavel S.; Polyakov, Alexander Y.; Lee, In-Hwan; Pearton, Stephen J.

    2016-05-01

    A movement of basal plane segments of dislocations in GaN films grown by epitaxial lateral overgrowth under low energy electron beam irradiation (LEEBI) was studied by the electron beam induced current (EBIC) method. Only a small fraction of the basal plane dislocation segments were susceptible to irradiation and the movement was limited to relatively short distances. The effect is explained by the radiation enhanced dislocation glide (REDG) in the structure with strong pinning. A dislocation velocity under LEEBI with a beam current lower than 1 nA was estimated as about 10 nm/s. The results assuming the REDG for prismatic plane dislocations were presented.

  18. Pediatric Monteggia Fracture-Dislocations: Avoiding Problems and Managing Complications.

    PubMed

    Chin, Kenneth; Kozin, Scott H; Herman, Martin; Horn, Bernard D; Eberson, Craig P; Bae, Donald S; Abzug, Joshua

    2016-01-01

    Monteggia fracture-dislocations typically involve a dislocation of the radial head with an associated fracture of the ulnar shaft. The prompt diagnosis and treatment of these acute injuries result in excellent outcomes. Unfortunately, a Monteggia fracture-dislocation is often missed during diagnostic testing and results in a chronic Monteggia fracture-dislocation. The subsequent timing and treatment of chronic Monteggia fracture-dislocations are debatable because outcomes are suboptimal. Therefore, it is critical that the initial injury be correctly diagnosed and treated as close to the time of injury as possible to ensure excellent outcomes. PMID:27049208

  19. The Older Worker's Stake in Workers' Compensation

    ERIC Educational Resources Information Center

    Berkowitz, Monroe

    1975-01-01

    State Workers' Compensation programs can add another barrier for older workers to surmount at the hiring gate. State programs do not furnish adequate or equitable protection, and the National Commission on State Workmen's Compensation Laws has made recommendations to improve coverage; new standards must be met by July, 1975. (Author)

  20. Suture rupture in acromioclavicular joint dislocations treated with flip buttons.

    PubMed

    Motta, Pierorazio; Maderni, Alberto; Bruno, Laura; Mariotti, Umberto

    2011-02-01

    Acute acromioclavicular joint dislocations (ACDs) may be treated arthroscopically with flip buttons. This extra-articular fixation is easy to implant and is well tolerated. Between 2007 and 2009, 20 ACD patients (2 women and 18 men; mean age, 32 years) had surgery by the arthroscopic TightRope technique (Arthrex, Naples, FL). The main complication of this technique that has been reported is the partial loss of reduction at follow-up due to clavicular osteolysis under the superior flip button. We describe 4 cases with loss of reduction due to rupture of the sutures running across the buttons: 2 women with joint hyperlaxity and acute Rockwood grade IV ACD and 2 men, heavy manual workers, with joint hyperlaxity and acute Rockwood grade IV ACD. The use of flip buttons might not be indicated in patients with joint hyperlaxity because they are able to obtain immediate stability only on the vertical plane and not on the horizontal plane. Anteroposterior movements of the acromioclavicular joint might rub the suture against the bone tunnels leading to wear and cutting. PMID:21266279

  1. REACH: An Individualized AE Program for Workers.

    ERIC Educational Resources Information Center

    Lake, Karen E.

    1980-01-01

    Renewed Expectations for Adults in Continuing Higher Education (Project REACH) provides educational services tailored to the needs of blue-collar workers, including courses on audiocassette tapes and simplified registration procedures. The program has been enthusiastically received by people who had faced many barriers to continuing education. (SK)

  2. CTE's Role in Worker Retraining. Issue Brief

    ERIC Educational Resources Information Center

    Association for Career and Technical Education (NJ1), 2010

    2010-01-01

    This Issue Brief will explore the essential role that career and technical education programs play in addressing many of the issues faced by unemployed and underemployed workers. These programs target the adult learner through short-term and accelerated courses; utilize flexible learning approaches to account for students' other responsibilities;…

  3. Understanding Learning Styles of Older Workers.

    ERIC Educational Resources Information Center

    Withnall, Alexandra

    2001-01-01

    A study of the learning styles of British older workers (predominantly women) in service occupations used the Adult Learning Styles Inventory by Rundle and Dunn, which is based on preferred environmental conditions. Respondents recognized their own learning profiles and understood possible causes of past learning difficulties. A simpler…

  4. Re-Training of Older Workers.

    ERIC Educational Resources Information Center

    Iron and Steel Industry Training Board, London (England).

    Designed to assist training staff in the planning and implementation of training for older workers, this guide indicates: the main problem areas; the extent and importance of the various requirements; some industrial experience in dealing with such problems; and some further resources of information on particular aspects of training of adults. The…

  5. Dislocation dynamics in hexagonal close-packed crystals

    DOE PAGESBeta

    Aubry, S.; Rhee, M.; Hommes, G.; Bulatov, V. V.; Arsenlis, A.

    2016-04-14

    Extensions of the dislocation dynamics methodology necessary to enable accurate simulations of crystal plasticity in hexagonal close-packed (HCP) metals are presented. They concern the introduction of dislocation motion in HCP crystals through linear and non-linear mobility laws, as well as the treatment of composite dislocation physics. Formation, stability and dissociation of and other dislocations with large Burgers vectors defined as composite dislocations are examined and a new topological operation is proposed to enable their dissociation. Furthermore, the results of our simulations suggest that composite dislocations are omnipresent and may play important roles both in specific dislocation mechanisms and in bulkmore » crystal plasticity in HCP materials. While fully microscopic, our bulk DD simulations provide wealth of data that can be used to develop and parameterize constitutive models of crystal plasticity at the mesoscale.« less

  6. Dislocations With Edge Components in Nanocrystalline bcc Mo

    SciTech Connect

    G. M. Cheng; W. Z. Xu; W. W. Jian; H. Yuan; M. H. Tsai; Y. T. Zhu; Y. F. Zhang; Paul C. Millett

    2013-07-01

    We report high-resolution transmission electron microscopy (HRTEM) observation of a high density of dislocations with edge components (approximately 1016 m-2) in nanocrystalline (NC) body-centered cubic (bcc) Mo prepared by high-pressure torsion. We also observed for the first time of the 1/2 <111> and <001> pure edge dislocations in NC Mo. Crystallographic analysis and image simulations reveal that the best way using HRTEM to study dislocations with edge components in bcc systems is to take images along <110> zone axis, from which it is possible to identify 1/2 <111> pure edge dislocations, and edge components of 1/2 <111> and <001> mixed dislocations. The <001> pure edge dislocations can only be identified from <100> zone axis. The high density of dislocations with edge components is believed to play a major role in the reduction of strain rate sensitivity in NC bcc metals and alloys.

  7. X-ray diffraction from hexagonal dislocation networks

    NASA Astrophysics Data System (ADS)

    Kopp, Viktor S.; Kaganer, Vladimir M.

    2014-10-01

    We built the honeycomb networks of misfit dislocations by combining angular dislocations. Two different models of the disorder in the dislocation network are explored, the random shifts of nodes and random sources of distortion. The displacement fields of disturbed dislocation networks are used to simulate the X-ray diffraction patterns by Monte Carlo method. We find that substantial disorder is needed for random shifts to be experimentally observable as diffuse scattering. The model of random distortion sources produces comparable diffuse scattering with the dislocation network looking closer to the initial perfect structure. The diffraction patterns due to distorted honeycomb dislocation networks are compared with the ones due to triangular networks of straight dislocations. The disorder parameters of the latter networks can be chosen to produce diffraction patterns similar to the former.

  8. Observation of dislocations and twins in explosively compacted alumina

    SciTech Connect

    Yust, C.S.; Harris, L.A.

    1980-01-01

    The microstructure at the half-radius position of a polycrystalline alumina rod formed by explosive compaction has been studied by transmission electron microscopy. The as-compacted lattice is composed of differently misoriented bands aligned predominantly in one direction. Such bands may correspond to frequently observed shock lamellae. The band edges are defined by dislocation arrays lying on the basal planes of the hexagonal alumina lattice. The dislocations have Burgers vectors of the type (1120) and (1010), which are the Burgers vectors of slip dislocations in the basal plane. Basal plane twinning is also observed, and the twin boundaries are found to contain interfacial dislocations. While dislocation generation occurs primarily on basal planes, some dislocation activity is also noted on prism, (1100), and on rhombohedral, (1101), planes. Nonbasal twinning, however, has not been detected. The lattice damage is discussed in terms of possible dislocation and twinning mechanisms.

  9. Dislocation dynamics in hexagonal close-packed crystals

    NASA Astrophysics Data System (ADS)

    Aubry, S.; Rhee, M.; Hommes, G.; Bulatov, V. V.; Arsenlis, A.

    2016-09-01

    Extensions of the dislocation dynamics methodology necessary to enable accurate simulations of crystal plasticity in hexagonal close-packed (HCP) metals are presented. They concern the introduction of dislocation motion in HCP crystals through linear and non-linear mobility laws, as well as the treatment of composite dislocation physics. Formation, stability and dissociation of < c + a > and other dislocations with large Burgers vectors defined as composite dislocations are examined and a new topological operation is proposed to enable their dissociation. The results of our simulations suggest that composite dislocations are omnipresent and may play important roles both in specific dislocation mechanisms and in bulk crystal plasticity in HCP materials. While fully microscopic, our bulk DD simulations provide wealth of data that can be used to develop and parameterize constitutive models of crystal plasticity at the mesoscale.

  10. The kink-pair nucleation in edge dislocation motion

    NASA Astrophysics Data System (ADS)

    Yu, Song; Wang, Chong-Yu; Yu, Tao

    2009-03-01

    The motion of edge dislocations (EDs) and kinked EDs in body-centered cubic Fe are studied at atom level. We find the kink-pair nucleation mechanism directly from the atom configuration evolution of dislocation, the EDs move primarily by the kink-pair nucleation, and the pre-existing kink does not affect this motion mode. The result is in agreement with the energy calculation. Furthermore, the Peierls stress, dislocation velocity, and phonon-drag coefficient are discussed. There are obviously two motion regions with different stresses. In the low-stress region, the stress exercises a great influence on the dislocation motion, the dislocation velocity increase significantly with the increase of stress. In the high-stress region, however, phonon drag practice a dominant factor on the dislocation motion, the dislocation move with approximately constant speed close to the transverse speed of sound.

  11. Worker-to-Worker Violence in Hospitals

    PubMed Central

    Hamblin, Lydia E.; Essenmacher, Lynnette; Ager, Joel; Upfal, Mark; Luborsky, Mark; Russell, Jim; Arnetz, Judith

    2016-01-01

    Worker-to-worker (Type III) violence is prevalent in health care settings and has potential adverse consequences for employees and organizations. Little research has examined perpetrator characteristics of this type of violence. The current study is a descriptive examination of the common demographic and work-related characteristics of perpetrators of Type III workplace violence among hospital workers. Analysis was based on documented incidents of Type III violence reported within a large hospital system from 2010 to 2012. Nurses were involved as either the perpetrator or target in the five most common perpetrator–target dyads. Incidence rate ratios revealed that patient care associates and nurses were significantly more likely to be perpetrators than other job titles. By examining characteristics of perpetrators and common worker dyads involved in Type III workplace violence, hospital stakeholders and unit supervisors have a starting point to develop strategies for reducing conflict between workers. PMID:26450899

  12. Superclimb of Dislocations in Solid 4He

    NASA Astrophysics Data System (ADS)

    Kuklov, Anatoly

    2011-03-01

    Edge dislocation with superfluid core can perform superclimb -- non-conservative motion (climb) assisted by superflow along its core. Such dislocation, with Burgers vector along the C-axis, has been found in ab initio simulations of hcp solid 4. Uniform network of superclimbing dislocations can induce isochoric compressibility which is finite (in contrast to ideal solid where it vanishes) and, practically, independent of the network density. Here N is total number of atoms and is chemical potential. Such giant response has been observed by Ray and Hallock during superfluid flow events through solid He4. Study of superclimbing dislocation within the model of Granato-Lücke string, subjected to Peierls potential and to vanishing bias by , has found that exhibits wide peak in the intermediate range of temperatures (T) - above some determined by Peierls energy and below above which superfluidity of the core essentially vanishes. Non-Luttinger type behavior characterized by K scaling as some power χ of dislocation length is observed in the wide peak region. Biasing superclimbing dislocation by finite μ (due to a contact with liquid through vycor electrodes,) can induce core roughening caused by thermally assisted tunneling of jog-antijog pairs through the barrier produced by combination of Peierls potential and the bias. The threshold for this effect scales as with some power a~ 1.7. The roughening is found to be hysteretic below some temperature Thyst , with TR determining temperature of thermal roughening, He exhibits strong and narrow resonant peak leading to a dip in the core superfluid sound velocity. This mechanism is proposed as an explanation for a strong and narrow dip observed in critical superflow rate. It is found that the dip characteristics are sensitive to the bias by μ and, therefore, this can be used as a test for the proposed mechanism. It is also predicted that the dip depth at given μc ~ 1 /La should be periodic in χ with the period T . This

  13. Low energy dislocation structures in epitaxy

    NASA Technical Reports Server (NTRS)

    Van Der Merwe, Jan H.; Woltersdorf, J.; Jesser, W. A.

    1986-01-01

    The principle of minimum energy was applied to epitaxial interfaces to show the interrelationship beteen misfit, overgrowth thickness and misfit dislocation spacing. The low energy dislocation configurations were presented for selected interfacial geometries. A review of the interfacial energy calculations was made and a critical assessment of the agreement between theory and experiment was presented. Modes of misfit accommodation were presented with emphasis on the distinction between kinetic effects and equilibrium conditions. Two-dimensional and three-dimensional overgrowths were treated together with interdiffusion-modified interfaces, and several models of interfacial structure were treated including the classical and the current models. The paper is concluded by indicating areas of needed investigation into interfacial structure.

  14. Characterization of dislocation wall spacing distributions

    SciTech Connect

    Godfrey, A.; Hughes, D.A.

    1997-12-31

    While conventionally the length scale of dislocation microstructures has been characterized by only a mean value it is also of interest to know the shape of the wall spacing distribution. In order to investigate the ability to characterize such spacing distributions for near-planar boundaries a model has been developed allowing the construction of a series of dislocation walls that can be sectioned in any plane allowing spacing distributions of the traces to be calculated. Results suggest that distribution shape is not adversely affected by either test section or by realistically low numbers of measurements. Consequently experimental measurements have been made on both low strain ({epsilon} = 0.2 and {epsilon} = 0.3) and high strain ({epsilon} = 2.7) samples. The distributions for all three strains exhibit similar shapes and can be scaled to a single curve for the probability density function.

  15. Treatment of complex elbow fracture-dislocations.

    PubMed

    Chan, Kevin; King, Graham J W; Faber, Kenneth J

    2016-06-01

    Successful management of complex elbow fracture-dislocations requires, in part, recognition of the overall injury pattern, which can aid in the identification of concomitant bony and soft tissue injuries. Trans-olecranon fracture-dislocations are best treated surgically with stable anatomic restoration of the trochlear notch. Terrible triad elbow injuries are believed to be caused by a valgus posterolateral force. Although select terrible triad injuries can be managed non-operatively, the majority of injuries are treated with stable surgical repair to allow early elbow motion. Unlike terrible triads, varus posteromedial forces are theorized to cause anteromedial coronoid fractures. These are usually associated with LCL disruptions, but do not have concomitant MCL or radial head injuries. A subset of anteromedial coronoid fractures can also be managed non-operatively. Internal fixation is recommended for injuries associated with large fracture fragments or elbow instability preventing early motion. PMID:26984334

  16. Nanovoid Cavitation by Dislocation Emission in Aluminum

    NASA Astrophysics Data System (ADS)

    Marian, Jaime; Knap, Jaroslaw; Ortiz, Michael

    2004-10-01

    This Letter is concerned with the determination of the transition paths attendant to nanovoid growth in aluminum under hydrostatic tension. The analysis is, therefore, based on energy minimization at 0K. Aluminum is modeled by the Ercolessi-Adams embedded-atom method, and spurious boundary artifacts are mitigated by the use of the quasicontinuum method. Our analysis reveals several stages of pressure buildup separated by yield points. The first yield point corresponds to the formation of highly stable tetrahedral dislocation junctions around the surfaces of the void. The second yield point is caused by the dissolution of the tetrahedral structures and the emission of conventional 1/2<110>{111} and anomalous 1/2<110>{001} dislocation loops.

  17. First principles determination of dislocation properties.

    SciTech Connect

    Hamilton, John C.

    2003-12-01

    This report details the work accomplished on first principles determination of dislocation properties. It contains an introduction and three chapters detailing three major accomplishments. First, we have used first principle calculations to determine the shear strength of an aluminum twin boundary. We find it to be remarkably small ({approx}17 mJ/m{sup 2}). This unexpected result is explained and will likely pertain for many other grain boundaries. Second, we have proven that the conventional explanation for finite grain boundary facets is wrong for a particular aluminum grain boundary. Instead of finite facets being stabilized by grain boundary stress, we find them to originate from kinetic effects. Finally we report on a new application of the Frenkel-Kontorova model to understand reconstructions of (100) type surfaces. In addition to the commonly accepted formation of rectangular dislocation arrays, we find numerous other possible solutions to the model including hexagonal reconstructions and a clock-rotated structure.

  18. Dislocations: 75 years of Deformation Mechanisms

    NASA Technical Reports Server (NTRS)

    Schneider, Judy

    2009-01-01

    The selection of papers presented in this section reflect on themes to be explored at the "Dislocations: 75 years of Deformation Mechanisms" Symposium to be held at the Annual 2009 TMS meeting. The symposium was sponsored by the Mechanical Behavior of Materials Committee to give tribute to the evolution of a concept that has formed the basis of our mechanistic understanding of how crystalline solids plastically deform and how they fail.

  19. Energetics and Noise in dislocation patterning.

    SciTech Connect

    Thomson, R. M.; Koslowski, M.; LeSar, R. ,

    2004-01-01

    The competition between energy and noise in the patterning transition in deformation is explored by employing a 2D model of parallel straight edge dislocations. We define a generalized force for ordering and show that at mechanical equilibrium, the ordering force is equal to the average back stress noise on the slip plane. We consider a system subjected to a total external strain that is a uniform linear function of time. When the external stress reaches a critical value that depends on the instantaneous state of strain and dislocation content, a discrete strain event occurs (what we have called elsewhere a percolation event) with the formation of one or perhaps a few micro slip steps on the surface. Within these micro slip bands, the dislocation content increases in a time short compared to the time between strain events. After the stress drop associated with the stain event, the strain stops. During the time between events, the configuration relaxes to a new equilibrium configuration, which may include thermally generated recovery. As the stress again builds owing to the continuously increasing total strain, it reaches a new critical stress determined by the newly achieved dislocation configuration. Our modeling addresses the changes during the relaxation of the system in the time between events. In our model, the initial state is a random configuration i.e., it does not contain any memory of the previous state of the deforming system. This is an extreme assumption, because in a real system, the order will evolve from one event to the next. Nevertheless, if the real system does order, we expect this to be captured in the model - we will simply be careful not to predict the quantitative order in the evolving system from our modeling.

  20. Tamponade following sternoclavicular dislocation surgical fixation.

    PubMed

    Bensafi, H; Laffosse, J-M; Taam, S A; Molinier, F; Chaminade, B; Puget, J

    2010-05-01

    The authors report a case of posterior sternoclavicular dislocation surgically reduced and stabilized with tenodesis, according to the Burrows technique completed by temporary wire fixation. The patient presented postoperative pericardiac tamponade appearing progressively from brachiocephalic blood vessels bleeding. Emergency drainage was surgically placed associated with removal of the material, thus curing the patient. This complication, although exceptional, formally contraindicates the use of wire fixation in surgery of the sternoclavicular joint. PMID:20488152

  1. Types of Traumatic Lens Dislocations at Larkana.

    PubMed

    Shah, Syed Imtiaz Ali; Shah, Shujaat Ali; Rai, Partab; Siddiqui, Shahid Jamal; Abbasi, Safdar Ali; Katpar, Naeem Akhtar

    2016-08-01

    The objective of this study was to determine the pattern of traumatic lens dislocations presenting at our institute. This may help develop the preventive strategies. The number of cases of traumatic lens dislocations, presented at the Department of Ophthalmology, Chandka Medical College, Larkana, Pakistan, from January 2002 to June 2015, were 59 including 61.02% (n=36) males and 38.98% (n=23) females. Cause of trauma was wood or plant impalement in 35.6% (n=21) cases, cracker blast in 13.55% (n=8) cases, fall on ground in 11.86% (n=7) cases, penetrating injuries with needle, scissors or knife in 10.16% (n=6) cases, road traffic accidents in 10.16% (n=6) cases, sports injuries (cricket ball and gulle danda) in 8.47% (n=5) cases, firearm injuries in 5.1% (n=3) cases, and fist hitting in 5.1% (n=3) cases. Lens was dislocated posteriorly in 33.90% (n=20) cases, anteriorly in 25.42% (n=15) cases, inferiorly in 11.86% (n=7) cases, medially in 10.17% (n=6) cases, laterally in 10.17% (n=6) cases, superiorly in 6.78% (n=4) cases, and a single (1.69%) case of lenticele was seen. PMID:27539772

  2. Open Galeazzi fracture with ipsilateral elbow dislocation.

    PubMed

    Adanır, Oktay; Yüksel, Serdar; Beytemur, Ozan; Güleç, M Akif

    2016-08-01

    Combination of the Galeazzi fracture and dislocation of the elbow joint in same extremity is very rare. In this article, we report a 26-year-old male patient with a posterolateral dislocation of the elbow and ipsilateral volar type Galeazzi fracture. We performed closed reduction for the elbow dislocation during admission to the emergency department. Patient was taken to the operating room in the sixth hour of his application to emergency department and open wound on the ulnovolar region of the wrist was closed primarily after irrigation and debridement. We performed open reduction and internal fixation of the radial fracture with a dynamic compression plate. After fixation, we evaluated the stability of the elbow joint and distal radioulnar joint. Distal radioulnar joint was unstable under fluoroscopic examination and fixed with one 1.8 mm Kirschner wire in a pronated position. Then, elbow joint was stable. One year after surgery, patient had no pain or sings of instability. At the last follow-up, range of motion of the elbow was 10°-135° and forearm pronation and supination were 70°. PMID:27499325

  3. Dislocation Theory of the Fatigue of Metals

    NASA Technical Reports Server (NTRS)

    Machlin, E S

    1949-01-01

    A dislocation theory of fatigue failure for annealed solid solutions is presented. On the basis of this theory, an equation giving the dependence of the number of cycles for failure on the stress, the temperature, the material parameters, and the frequency is derived for uniformly stressed specimens. The equation is in quantitative agreement with the data. Inasmuch as one material parameter is indicated to be temperature-dependent and its temperature dependence is unknown, it is impossible to predict the temperature dependence of the number of cycles for failure. A predicted quantitative correlation between fatigue and creep was found to exist, which suggests the practical possibility of obtaining fatigue data for annealed solid solutions and elements from steady-state creep-rate data for these materials. As a result of this investigation, a modification of the equation for the steady-state creep rate previously developed on the basis of the dislocation theory is suggested. Additional data are required to verify completely the dislocation theory of fatigue.

  4. Dislocation movement and hysteresis in Maraging blades

    NASA Astrophysics Data System (ADS)

    Di Cintio, Arianna; Marchesoni, Fabio; Ascione, Maria; Bhawal, Abhik; De Salvo, Riccardo

    2009-10-01

    All seismic isolation systems developed for gravitational-wave interferometric detectors, such as LIGO, Virgo and TAMA, make use of Maraging steel blades. The dissipation properties of these blades have been studied at low frequencies, by using a geometric anti-spring (GAS) filter, which allowed the exploration of resonant frequencies below 100 mHz. At this frequency an anomalous transfer function was observed in the GAS filter: this is one of several motivations for this work. The many unexpected effects observed and measured are explainable by the collective movement of dislocations inside the material described with the statistic of self-organised criticality. At low frequencies, below 200 mHz, the dissipation mechanism can subtract elasticity from the system even leading to sudden collapse. While Young's modulus is weaker, excess dissipation is observed. At higher frequencies the applied stress is probably too fast to allow the full growth of dislocation avalanches, and less losses are observed, thus explaining the higher Q-factor in this frequency range. The domino effect that leads to the release of entangled dislocations allows the understanding of the random walk of the Virgo and TAMA inverted pendula, the anomalous GAS filter transfer function as well as the loss of predictability of the ring-down decay in the LIGO seismic attenuation system inverted pendula.

  5. Management of an Uncomplicated Posterior Elbow Dislocation

    PubMed Central

    Blackard, Douglas; Sampson, Jo-Ann

    1997-01-01

    Objective: To present a case of an uncomplicated posterior elbow dislocation in a US World Cup athlete and discuss her rehabilitation. Background: Traditional protocol for management of this injury has been splint immobilization for several weeks, but research suggests a shortened duration of immobilization and early active motion. Differential Diagnosis: Elbow dislocation with possible fracture. Treatment: The dislocation was reduced and a compression bandage and sling were applied. The sports medicine staff and athlete determined that rehabilitation would involve limited immobilization with a posterior splint. Also, active range-of- motion exercises were to be incorporated early in the range-of- motion program to decrease pain at the articulation. Uniqueness: The athlete was not immobilized and her aggressive five-phase rehabilitation program progressed according to decrease in inflammation and increase in range of motion and strength. Conclusions: Shortened immobilization and return to World Championship competition 6 weeks postinjury had no longterm adverse effects on the athlete. ImagesFig 1.Fig 2.Fig 3.Fig 4.Fig. 5. PMID:16558436

  6. Probing the character of ultra-fast dislocations

    DOE PAGESBeta

    Rudd, R. E.; Ruestes, C. J.; Bringa, E. M.; Remington, B. A.; Remington, T. P.; Meyers, M. A.

    2015-11-23

    Plasticity is often controlled by dislocation motion, which was first measured for low pressure, low strain rate conditions decades ago. However, many applications require knowledge of dislocation motion at high stress conditions where the data are sparse, and come from indirect measurements dominated by the effect of dislocation density rather than velocity. Here we make predictions based on atomistic simulations that form the basis for a new approach to measure dislocation velocities directly at extreme conditions using three steps: create prismatic dislocation loops in a near-surface region using nanoindentation, drive the dislocations with a shockwave, and use electron microscopy tomore » determine how far the dislocations moved and thus their velocity at extreme stress and strain rate conditions. We report on atomistic simulations of tantalum that make detailed predictions of dislocation flow, and find that the approach is feasible and can uncover an exciting range of phenomena, such as transonic dislocations and a novel form of loop stretching. Furthermore, the simulated configuration enables a new class of experiments to probe average dislocation velocity at very high applied shear stress.« less

  7. Probing the character of ultra-fast dislocations.

    PubMed

    Ruestes, C J; Bringa, E M; Rudd, R E; Remington, B A; Remington, T P; Meyers, M A

    2015-01-01

    Plasticity is often controlled by dislocation motion, which was first measured for low pressure, low strain rate conditions decades ago. However, many applications require knowledge of dislocation motion at high stress conditions where the data are sparse, and come from indirect measurements dominated by the effect of dislocation density rather than velocity. Here we make predictions based on atomistic simulations that form the basis for a new approach to measure dislocation velocities directly at extreme conditions using three steps: create prismatic dislocation loops in a near-surface region using nanoindentation, drive the dislocations with a shockwave, and use electron microscopy to determine how far the dislocations moved and thus their velocity at extreme stress and strain rate conditions. We report on atomistic simulations of tantalum that make detailed predictions of dislocation flow, and find that the approach is feasible and can uncover an exciting range of phenomena, such as transonic dislocations and a novel form of loop stretching. The simulated configuration enables a new class of experiments to probe average dislocation velocity at very high applied shear stress. PMID:26592764

  8. Probing the character of ultra-fast dislocations

    PubMed Central

    Ruestes, C. J.; Bringa, E. M.; Rudd, R. E.; Remington, B. A.; Remington, T. P.; Meyers, M. A.

    2015-01-01

    Plasticity is often controlled by dislocation motion, which was first measured for low pressure, low strain rate conditions decades ago. However, many applications require knowledge of dislocation motion at high stress conditions where the data are sparse, and come from indirect measurements dominated by the effect of dislocation density rather than velocity. Here we make predictions based on atomistic simulations that form the basis for a new approach to measure dislocation velocities directly at extreme conditions using three steps: create prismatic dislocation loops in a near-surface region using nanoindentation, drive the dislocations with a shockwave, and use electron microscopy to determine how far the dislocations moved and thus their velocity at extreme stress and strain rate conditions. We report on atomistic simulations of tantalum that make detailed predictions of dislocation flow, and find that the approach is feasible and can uncover an exciting range of phenomena, such as transonic dislocations and a novel form of loop stretching. The simulated configuration enables a new class of experiments to probe average dislocation velocity at very high applied shear stress. PMID:26592764

  9. Probing the character of ultra-fast dislocations

    SciTech Connect

    Rudd, R. E.; Ruestes, C. J.; Bringa, E. M.; Remington, B. A.; Remington, T. P.; Meyers, M. A.

    2015-11-23

    Plasticity is often controlled by dislocation motion, which was first measured for low pressure, low strain rate conditions decades ago. However, many applications require knowledge of dislocation motion at high stress conditions where the data are sparse, and come from indirect measurements dominated by the effect of dislocation density rather than velocity. Here we make predictions based on atomistic simulations that form the basis for a new approach to measure dislocation velocities directly at extreme conditions using three steps: create prismatic dislocation loops in a near-surface region using nanoindentation, drive the dislocations with a shockwave, and use electron microscopy to determine how far the dislocations moved and thus their velocity at extreme stress and strain rate conditions. We report on atomistic simulations of tantalum that make detailed predictions of dislocation flow, and find that the approach is feasible and can uncover an exciting range of phenomena, such as transonic dislocations and a novel form of loop stretching. Furthermore, the simulated configuration enables a new class of experiments to probe average dislocation velocity at very high applied shear stress.

  10. Worker honey bee pheromone regulation of foraging ontogeny

    NASA Astrophysics Data System (ADS)

    Pankiw, Tanya

    The evolution of sociality has configured communication chemicals, called primer pheromones, which play key roles in regulating the organization of social life. Primer pheromones exert relatively slow effects that fundamentally alter developmental, physiological, and neural systems. Here, I demonstrate how substances extracted from the surface of foraging and young pre-foraging worker bees regulated age at onset of foraging, a developmental process. Hexane-extractable compounds washed from foraging workers increased foraging age compared with controls, whereas extracts of young pre-foraging workers decreased foraging age. This represents the first known direct demonstration of primer pheromone activity derived from adult worker bees.

  11. A closed-form criterion for dislocation emission in nano-porous materials under arbitrary thermomechanical loading

    NASA Astrophysics Data System (ADS)

    Wilkerson, J. W.; Ramesh, K. T.

    2016-01-01

    Our traditional view of void nucleation is associated with interface debonding at second-phase particles. However, under extreme dynamic loading conditions second-phase particles may not necessarily be the dominant source of void nucleation sites. A few key experimental observations of laser spall surfaces support this assertion. Here, we describe an alternative mechanism to the traditional view, namely shock-induced vacancy generation and clustering followed by nanovoid growth mediated by dislocation emission. This mechanism only becomes active at very large stresses. It is therefore desirable to establish a closed-form criterion for the macroscopic stress required to activate dislocation emission in porous materials. Following an approach similar to Lubarda and co-workers, we derive the desired criterion by making use of stability arguments applied to the analytic solutions for the elastic interactions of dislocations and voids. Our analysis significantly extends that of Lubarda and co-workers by accounting for a more general stress state, finite porosity, surface tension, as well as temperature and pressure dependence. The resulting simple stress-based criterion is validated against a number of molecular dynamics simulations with favorable agreement.

  12. Sternoclavicular dislocation: case report and surgical technique.

    PubMed

    Terra, Bernardo Barcellos; Rodrigues, Leandro Marano; Pádua, David Victoria Hoffmann; Martins, Marcelo Giovanini; Teixeira, João Carlos de Medeiros; De Nadai, Anderson

    2015-01-01

    Sternoclavicular dislocations account for less than 5% of all dislocations of the scapular belt. Most cases of anterior dislocation of the sternoclavicular joint do not present symptoms. However, some patients may develop chronic anterior instability and remain symptomatic, and surgical treatment is indicated in these cases. There is a scarcity of reports in the literature relating to reconstruction using the long palmar tendon in cases of traumatic anterior instability. Although rare, these injuries deserve rapid diagnosis and efficient treatment in order to avoid future complications. The aim of this report was to report on a case of a motocross competitor who developed chronic traumatic anterior instability of the sternoclavicular joint and underwent surgical reconstruction using the autogenous long palmar tendon. The patient was a 33-year-old man with a history of anterior dislocation of the sternoclavicular subsequent to a fall during a maneuver in a motocross competition. Conservative treatment was instituted initially, consisting of use of a functional sling to treat the symptoms for 3 weeks, along with physiotherapeutic rehabilitation for 3 months. We chose to use a modification of the "figure of eight" technique based on the studies by Spencer and Kuhn. A longitudinal incision of approximately 10 cm was made at the level of the sternoclavicular joint. The graft from the ipsilateral long palmar tendon was passed through the orifices in the form of a modified "figure of eight" and its ends were sutured together. The patient was immobilized using an American sling for 4 weeks. After 6 months of follow-up, the patient no longer presented pain or instability when movement of the sternoclavicular joint was required. Minor discomfort and slight prominence of the sternoclavicular joint continued to be present but did not affect the patient's activities. Thus, the patient was able to return to racing 6 months after the operation. Our study presented a case of

  13. Sternoclavicular dislocation: case report and surgical technique☆

    PubMed Central

    Terra, Bernardo Barcellos; Rodrigues, Leandro Marano; Pádua, David Victoria Hoffmann; Martins, Marcelo Giovanini; Teixeira, João Carlos de Medeiros; De Nadai, Anderson

    2015-01-01

    Sternoclavicular dislocations account for less than 5% of all dislocations of the scapular belt. Most cases of anterior dislocation of the sternoclavicular joint do not present symptoms. However, some patients may develop chronic anterior instability and remain symptomatic, and surgical treatment is indicated in these cases. There is a scarcity of reports in the literature relating to reconstruction using the long palmar tendon in cases of traumatic anterior instability. Although rare, these injuries deserve rapid diagnosis and efficient treatment in order to avoid future complications. The aim of this report was to report on a case of a motocross competitor who developed chronic traumatic anterior instability of the sternoclavicular joint and underwent surgical reconstruction using the autogenous long palmar tendon. The patient was a 33-year-old man with a history of anterior dislocation of the sternoclavicular subsequent to a fall during a maneuver in a motocross competition. Conservative treatment was instituted initially, consisting of use of a functional sling to treat the symptoms for 3 weeks, along with physiotherapeutic rehabilitation for 3 months. We chose to use a modification of the “figure of eight” technique based on the studies by Spencer and Kuhn. A longitudinal incision of approximately 10 cm was made at the level of the sternoclavicular joint. The graft from the ipsilateral long palmar tendon was passed through the orifices in the form of a modified “figure of eight” and its ends were sutured together. The patient was immobilized using an American sling for 4 weeks. After 6 months of follow-up, the patient no longer presented pain or instability when movement of the sternoclavicular joint was required. Minor discomfort and slight prominence of the sternoclavicular joint continued to be present but did not affect the patient's activities. Thus, the patient was able to return to racing 6 months after the operation. Our study presented a case

  14. Low vaccination coverage for seasonal influenza and pneumococcal disease among adults at-risk and health care workers in Ireland, 2013: The key role of GPs in recommending vaccination.

    PubMed

    Giese, Coralie; Mereckiene, Jolita; Danis, Kostas; O'Donnell, Joan; O'Flanagan, Darina; Cotter, Suzanne

    2016-07-12

    The World Health Organization (WHO), and European Agencies recommend influenza vaccination for individuals at-risk due to age (≥65 years), underlying diseases, pregnancy and for health care workers (HCWs) in Europe. Pneumococcal vaccine is recommended for those at-risk of pneumococcal disease. In Ireland, vaccination uptake among at-risk adults is not routinely available. In 2013, we conducted a national survey among Irish residents ≥18 years of age, to estimate size and vaccination coverage of at-risk groups, and identify predictive factors for influenza vaccination. We used computer assisted telephone interviews to collect self-reported information on health, vaccination status, attitudes towards vaccination. We calculated prevalence and prevalence ratios (PR) using binomial regression. Overall, 1770 individuals participated. For influenza, among those aged 18-64 years, 22% (325/1485) [95%CI: 17%-20%] were at-risk; 28% [95%CI: 23%-33%] were vaccinated. Among those aged ≥65 years, 60% [95%CI: 54%-66%] were vaccinated. Influenza vaccine uptake among HCWs was 28% [95%CI: 21%-35%]. For pneumococcal disease, among those aged 18-64 years, 18% [95%CI: 16%-20%] were at-risk; 16% [95%CI: 12%-21%] reported ever-vaccination; among those aged ≥65 years, 36% [95%CI: 30%-42%] reported ever-vaccination. Main reasons for not receiving influenza vaccine were perceptions of not being at-risk, or not thinking of it; and among HCWs thinking that vaccination was not necessary or they were not at-risk. At-risk individuals were more likely to be vaccinated if their doctor had recommended it (PR 3.2; [95%CI: 2.4%-4.4%]) or they had access to free medical care or free vaccination services (PR 2.0; [95%CI: 1.5%-2.8%]). Vaccination coverage for both influenza and pneumococcal vaccines in at-risk individuals aged 18-64 years was very low. Influenza vaccination coverage among individuals ≥65 years was moderate. Influenza vaccination status was associated with GP vaccination

  15. Acute patellar dislocation with multiple ligament injuries after knee dislocation and single session reconstruction.

    PubMed

    Gormeli, Gokay; Gormeli, Cemile Ayse; Karakaplan, Mustafa; Gurbuz, Sukru; Ozdemir, Zeynep; Ozer, Mustafa

    2016-06-01

    Knee dislocation is a relatively rare condition of all orthopaedic injuries. Accompanying multiple ligament injuries are common after knee dislocations. A 41-year-old male presented to the emergency department suffering from right knee dislocation in June 2013. The patient had anterior cruciate ligament, medial collateral ligament (MCL), medial patellofemoral ligament (MPFL) rupture, and lateral meniscal tear. A single-bundle anatomic reconstruction, medial collateral ligament reconstruction, medial patellofemoral ligament reconstruction and meniscus repair were performed in single session. At twelve months follow-up; there was 160º flexion and 10° extension knee range of motion. Lysholm knee score was 90. Extensive forces can cause both MCL and MPFL injury due to overload and the anatomical relationship between these two structures. Therefore, patients with valgus instability should be evaluated for both MPFL and MCL tears to facilitate successful treatment. PMID:27339584

  16. Understanding dislocation mechanics at the mesoscale using phase field dislocation dynamics.

    PubMed

    Beyerlein, I J; Hunter, A

    2016-04-28

    In this paper, we discuss the formulation, recent developments and findings obtained from a mesoscale mechanics technique called phase field dislocation dynamics (PFDD). We begin by presenting recent advancements made in modelling face-centred cubic materials, such as integration with atomic-scale simulations to account for partial dislocations. We discuss calculations that help in understanding grain size effects on transitions from full to partial dislocation-mediated slip behaviour and deformation twinning. Finally, we present recent extensions of the PFDD framework to alternative crystal structures, such as body-centred cubic metals, and two-phase materials, including free surfaces, voids and bi-metallic crystals. With several examples we demonstrate that the PFDD model is a powerful and versatile method that can bridge the length and time scales between atomistic and continuum-scale methods, providing a much needed understanding of deformation mechanisms in the mesoscale regime. PMID:27002063

  17. Alternative Training Options for Structurally Unemployed Older Workers. Information Series No. 275.

    ERIC Educational Resources Information Center

    Helwig, Andrew A.

    The need for a national policy for the development and use of human resources is evident. One part of the human resource development issue centers around the needs of adult workers who are unemployed or threatended with unemployment because of structural changes in the labor market. The issue of retraining adult workers was examined in detail in…

  18. Atomistic simulations of dislocation pileup: Grain boundaries interaction

    SciTech Connect

    Wang, Jian

    2015-05-27

    Here, using molecular dynamics (MD) simulations, we studied the dislocation pileup–grain boundary (GB) interactions. Two Σ11 asymmetrical tilt grain boundaries in Al are studied to explore the influence of orientation relationship and interface structure on dislocation activities at grain boundaries. To mimic the reality of a dislocation pileup in a coarse-grained polycrystalline, we optimized the dislocation population in MD simulations and developed a predict-correct method to create a dislocation pileup in MD simulations. MD simulations explored several kinetic processes of dislocations–GB reactions: grain boundary sliding, grain boundary migration, slip transmission, dislocation reflection, reconstruction of grain boundary, and the correlation of these kinetic processes with the available slip systems across the GB and atomic structures of the GB.

  19. Patella dislocation following distal femoral replacement after bone tumour resection

    PubMed Central

    Akiyama, Toru; Kanda, Shotaro; Maeda, Akinori; Endo, Minoru; Saita, Kazuo

    2014-01-01

    We report the case of a 16-year-old girl with patella dislocation following distal femur replacement for a malignant tumour. We performed a medial plication and lateral release procedure to treat her persistent patellar dislocation after distal femur replacement following malignant tumour resection. This treatment improved the patient's gait ability dramatically. A distal femur reconstruction with a total knee arthroplasty (TKA) system for tumour resection is a frequently performed procedure. The reported incidence of patella dislocation following distal femur reconstruction with a TKA is 2.3%. However, treatment procedures for patella dislocation following a distal femur replacement after malignant tumour resection have not been studied extensively. To the best of our knowledge, this is the first English case report about patella dislocation following distal femoral replacement focusing on surgical treatment. Our experience suggests that treatment for patella dislocation following distal femur reconstruction with a TKA should be considered positively. PMID:25073529

  20. Glassy dislocation dynamics in 2D colloidal dimer crystals.

    PubMed

    Gerbode, Sharon J; Agarwal, Umang; Ong, Desmond C; Liddell, Chekesha M; Escobedo, Fernando; Cohen, Itai

    2010-08-13

    Although glassy relaxation is typically associated with disorder, here we report on a new type of glassy dynamics relating to dislocations within 2D crystals of colloidal dimers. Previous studies have demonstrated that dislocation motion in dimer crystals is restricted by certain particle orientations. Here, we drag an optically trapped particle through such dimer crystals, creating dislocations. We find a two-stage relaxation response where initially dislocations glide until encountering particles that cage their motion. Subsequent relaxation occurs logarithmically slowly through a second process where dislocations hop between caged configurations. Finally, in simulations of sheared dimer crystals, the dislocation mean squared displacement displays a caging plateau typical of glassy dynamics. Together, these results reveal a novel glassy system within a colloidal crystal. PMID:20868079

  1. Free energy of dislocations in a multi-slip geometry

    NASA Astrophysics Data System (ADS)

    Kooiman, M.; Hütter, M.; Geers, M. G. D.

    2016-03-01

    The collective dynamics of dislocations is the underlying mechanism of plastic deformation in metallic crystals. Dislocation motion in metals generally occurs on multiple slip systems. The simultaneous activation of different slip systems plays a crucial role in crystal plasticity models. In this contribution, we study the energetic interactions between dislocations on different slip systems by deriving the free energy in a multi-slip geometry. In this, we restrict ourselves to straight and parallel edge dislocations. The obtained free energy has a long-range mean-field contribution, a statistical contribution and a many-body contribution. The many-body contribution is a local function of the total dislocation density on each slip system, and can therefore not be written in terms of the net dislocation density only. Moreover, this function is a strongly non-linear and non-convex function of the density on different slip systems, and hence the coupling between slip systems is of great importance.

  2. Pattern formation in a minimal model of continuum dislocation plasticity

    NASA Astrophysics Data System (ADS)

    Sandfeld, Stefan; Zaiser, Michael

    2015-09-01

    The spontaneous emergence of heterogeneous dislocation patterns is a conspicuous feature of plastic deformation and strain hardening of crystalline solids. Despite long-standing efforts in the materials science and physics of defect communities, there is no general consensus regarding the physical mechanism which leads to the formation of dislocation patterns. In order to establish the fundamental mechanism, we formulate an extremely simplified, minimal model to investigate the formation of patterns based on the continuum theory of fluxes of curved dislocations. We demonstrate that strain hardening as embodied in a Taylor-type dislocation density dependence of the flow stress, in conjunction with the structure of the kinematic equations that govern dislocation motion under the action of external stresses, is already sufficient for the formation of dislocation patterns that are consistent with the principle of similitude.

  3. Dislocation distribution in large high-purity germanium crystal

    NASA Astrophysics Data System (ADS)

    Mei, Hao; Wang, Guojian; Mei, Dongming; Huang, Mianliang; Yang, Gang; Guan, Yutong; Cubed Collaboration

    2014-03-01

    We investigated the impacts of growth rate, time-temperature profile, thermal gradient on the dislocation distribution in large high-purity germanium crystal (12 cm in diameter) grown via Czochralski along <100>orientation. The time-temperature profiles of the crystal grown at different input power were investigated using direct measurements and computational modeling. The effect of crystallization speed on dislocation density is discussed from the context of thermal gradient during growth. Several samples from the grown crystals were used for this investigation. We measured dislocation density across the entire cross-section of the grown crystal through the microscope. By measuring and calculating the dislocation density, we were able to identify the denseness and the type of dislocation, which allows us to study how the thermal stress impacts the dislocation generation and distribution across the large grown crystals. This work is supported by DOE grant DE-FG02-10ER46709 and the state of South Dakota.

  4. Atomistic simulations of dislocation pileup: Grain boundaries interaction

    DOE PAGESBeta

    Wang, Jian

    2015-05-27

    Here, using molecular dynamics (MD) simulations, we studied the dislocation pileup–grain boundary (GB) interactions. Two Σ11 asymmetrical tilt grain boundaries in Al are studied to explore the influence of orientation relationship and interface structure on dislocation activities at grain boundaries. To mimic the reality of a dislocation pileup in a coarse-grained polycrystalline, we optimized the dislocation population in MD simulations and developed a predict-correct method to create a dislocation pileup in MD simulations. MD simulations explored several kinetic processes of dislocations–GB reactions: grain boundary sliding, grain boundary migration, slip transmission, dislocation reflection, reconstruction of grain boundary, and the correlation ofmore » these kinetic processes with the available slip systems across the GB and atomic structures of the GB.« less

  5. Influence of interfacial dislocations on hysteresis loops of ferroelectric films

    NASA Astrophysics Data System (ADS)

    Li, Y. L.; Hu, S. Y.; Choudhury, S.; Baskes, M. I.; Saxena, A.; Lookman, T.; Jia, Q. X.; Schlom, D. G.; Chen, L. Q.

    2008-11-01

    We investigated the influence of dislocations, located at the interface of a ferroelectric film and its underlying substrate, on the ferroelectric hysteresis loop including the remanent polarization and coercive field using phase-field simulations. We considered epitaxial ferroelectric BaTiO3 films and found that the hysteresis loop is strongly dependent on the type and density of interfacial dislocations. The dislocations that stabilize multiple ferroelectric variants and domains reduce the coercive field, and consequently, the corresponding remanent polarization also decreases.

  6. Dislocation dynamics during the growth of silicon ribbon

    NASA Technical Reports Server (NTRS)

    Dillon, O. W., Jr.; Tsai, C. T.; De Angelis, R. J.

    1986-01-01

    The thermal viscoplastic stresses and the dislocation densities in silicon ribbon are computed for an axially changing thermal profile by using an iterative finite difference method. A material constitutive equation (Haasen-Sumino model) which involves an internal variable (mobile dislocation density) is used. The results are interpreted as showing that there is a maximum width of silicon ribbon that can be grown when viscoplasticity and dislocations are considered. This maximum width limitation does not exist if the material behavior is elastic.

  7. Crystal geometry of screw dislocation glide in tungsten nanocrystals

    NASA Astrophysics Data System (ADS)

    Sadanov, E. V.

    2015-02-01

    A zigzag pattern of low-temperature dislocation glide occurring in tungsten nanocrystals in the intersecting planes {110} and {211}, which belong to the <111> crystallographic zone, has been revealed using field ion microscopy. It has been shown that cores of 1/2[111] screw dislocations are undissociated within the limits of the resolution of the field ion microscope. It has been found experimentally that surface atoms are displaced into metastable positions in the region of the trace of screw dislocation motion.

  8. Dislocations: do you want them moving or in 3D ?

    NASA Astrophysics Data System (ADS)

    Cordier, Patrick; Boioli, Francesca; Bollinger, Caroline; Idrissi, Hosni; Mussi, Alexandre; Clitton Nzogang, Billy; Schryvers, Dominique

    2016-04-01

    Plastic deformation of minerals and rocks can be explained in most cases by the presence of crystal defects. Among those, dislocations represent the most efficient strain-producing actors of deformation. The physics of deformation by dislocations is complex since it is intrinsically multiscale. At the atomic scale, the dislocation core structure controls a fundamental property: their mobility. However, the plastic strain results from the collective behavior of dislocations which can be understood only at the mesoscopic scale. Multiscale numerical modeling has provided a lot of insights on these aspects in the recent years, also in mineral physics. These progress were calling for parallel developments in experiments and characterization. Here we present two studies on dislocations in olivine deformed under lithospheric conditions based in recent developments in transmission electron microscopy. We present plastic deformation experiments performed on olivine in situ, in the transmission electron microscope, at room temperature. The ductile behavior is made possible thanks to the very small size of the specimens (maximum dimension < 5μm) which are prepared by focused ion beam and strained in a special Micro-Electro-Mechanical-System (MEMS) device called push-to-pull (PI 95 TEM PicoIndenter from Hysitron). By performing experiments under constant load, the velocity of [001] screw dislocations has been measured as a function of stress. This mobility law has then been introduced in a Dislocation Dynamics model to determine the stress strain curves. We present also some recent developments on electron tomography of dislocations performed on olivine. The difficulty is here to keep diffraction conditions strictly constant over a wide range of tilt acquisitions. We present some examples obtained by imaging dislocations in weak-beam dark-field using precession electron diffraction. The analysis of dislocation microstructures in 3D is used to characterize dislocations glide

  9. The equivalence between dislocation pile-ups and cracks

    NASA Technical Reports Server (NTRS)

    Liu, H. W.; Gao, Q.

    1990-01-01

    Cracks and dislocation pile-ups are equivalent to each other. In this paper, the physical equivalence between cracks and pile-ups is delineated, and the relationshps between crack-extension force, force on the leading dislocation, stress-intensity factor, and dislocation density are reviewed and summarized. These relations make it possible to extend quantitatively the recent advances in the concepts and practices of fracture mechanics to the studies of microfractures and microplastic deformations.

  10. Ultrahigh strength of dislocation-free Ni3Al nanocubes.

    PubMed

    Maaß, Robert; Meza, Lucas; Gan, Bin; Tin, Sammy; Greer, Julia R

    2012-06-25

    Individual Ni(3) Al nanocubes under pressure are investigated by comparing the compressive strength of both dislocation-free and irradiated Ni(3) Al nanocubes. The results are dicussed in light of the size-dependent and size-independent strength of face-centered cubic (fcc) nanocrystals in the framework of dislocation nucleation at free surfaces. This study sheds more light on the understanding of fundamental deformation mechanisms and size-affected strength in dislocation-free metallic nanocrystals. PMID:22454244

  11. Jaw Dislocation as an Unusual Complication of Upper Endoscopy

    PubMed Central

    Dellon, Evan S.; Steele, David

    2016-01-01

    This case report presents an unusual complication of upper endoscopy, resulting in jaw dislocation. Temporomandibular joint dislocation is commonly reported in association with anesthesia and intubation, but it is not widely recognized as a complication of gastrointestinal endoscopy. This report also reviews the current literature regarding this complication and discusses the potential causes of dislocation, differential diagnoses for jaw pain following endoscopy, and recommendations for prevention.

  12. Dislocation of the Temporomandibular Joint and Relocation Procedures.

    PubMed

    White, Thomas; Hedderick, Viki; Ramponi, Denise R

    2016-01-01

    Temporomandibular joint (TMJ) dislocation requires prompt medical attention due to the crucial impact of airway, nutrition acquisition, and communication. Recognition of this injury by the practitioner, based on clinical presentation and history, is paramount for identification of accurate diagnosis and prompt treatment of TMJ dislocation. Relocation or reduction methods vary on the basis of the severity of the injury and whether it is an acute or chronic dislocation. PMID:27482989

  13. New mechanism for dislocation blocking in strained layer epitaxial growth

    SciTech Connect

    Stach, E.A.; Schwarz, K.W.; Hull, R.; Ross, F.M.; Tromp, R.M.

    1999-09-14

    Dislocation interactions play a critical role in plasticity and heteroepitaxial strain relaxation. We use real time transmission electron microscopy observations of the interaction between threading and misfit dislocations in SiGe heterostructures to investigate interactions quantitatively. In addition to the expected long range blocking of threading segments, we observe a new short range mechanism which is significantly more effective. Simulations show that this reactive blocking occurs when two dislocations with the same Burgers vector reconnect.

  14. New mechanism for dislocation blocking in strained layer epitaxial growth

    PubMed

    Stach; Schwarz; Hull; Ross; Tromp

    2000-01-31

    Dislocation interactions play a critical role in plasticity and heteroepitaxial strain relaxation. We use real time transmission electron microscopy observations of the interaction between threading and misfit dislocations in SiGe heterostructures to investigate interactions quantitatively. In addition to the expected long-range blocking of threading segments, we observe a new short-range mechanism which is significantly more effective. Simulations show that this reactive blocking occurs when two dislocations with the same Burgers vector reconnect. PMID:11017412

  15. Edge Dislocations in Smectic-A Liquid Crystals

    NASA Astrophysics Data System (ADS)

    Ambrožič, M.; Slavinec, M.; Kralj, S.

    We study theoretically static structure and annihilation dynamics of edge dislocations in a smectic-A liquid crystal confined to a plan-parallel cell. The Landau-Ginzburg type phenomenological approach is used in terms of a complex order parameter. We investigate a structure of an isolated dislocation that is enforced by boundary conditions. We further follow the annihilation dynamics of a pair of dislocations into a defectless state.

  16. 20 CFR 663.160 - Are there particular core services an individual must receive before receiving intensive services...

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ....160 Employees' Benefits EMPLOYMENT AND TRAINING ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) ADULT AND DISLOCATED WORKER ACTIVITIES UNDER TITLE I OF THE WORKFORCE INVESTMENT ACT Delivery of Adult...

  17. 20 CFR 663.160 - Are there particular core services an individual must receive before receiving intensive services...

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ....160 Employees' Benefits EMPLOYMENT AND TRAINING ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) ADULT AND DISLOCATED WORKER ACTIVITIES UNDER TITLE I OF THE WORKFORCE INVESTMENT ACT Delivery of Adult...

  18. Surface dislocation nucleation controlled deformation of Au nanowires

    SciTech Connect

    Roos, B.; Kapelle, B.; Volkert, C. A.; Richter, G.

    2014-11-17

    We investigate deformation in high quality Au nanowires under both tension and bending using in-situ transmission electron microscopy. Defect evolution is investigated during: (1) tensile deformation of 〈110〉 oriented, initially defect-free, single crystal nanowires with cross-sectional widths between 30 and 300 nm, (2) bending deformation of the same wires, and (3) tensile deformation of wires containing coherent twin boundaries along their lengths. We observe the formation of twins and stacking faults in the single crystal wires under tension, and storage of full dislocations after bending of single crystal wires and after tension of twinned wires. The stress state dependence of the deformation morphology and the formation of stacking faults and twins are not features of bulk Au, where deformation is controlled by dislocation interactions. Instead, we attribute the deformation morphologies to the surface nucleation of either leading or trailing partial dislocations, depending on the Schmid factors, which move through and exit the wires producing stacking faults or full dislocation slip. The presence of obstacles such as neutral planes or twin boundaries hinder the egress of the freshly nucleated dislocations and allow trailing and leading partial dislocations to combine and to be stored as full dislocations in the wires. We infer that the twins and stacking faults often observed in nanoscale Au specimens are not a direct size effect but the result of a size and obstacle dependent transition from dislocation interaction controlled to dislocation nucleation controlled deformation.

  19. Fabrication of mesoscopic floating Si wires by introducing dislocations

    NASA Astrophysics Data System (ADS)

    Motohashi, Mitsuya; Shimizu, Kazuya; Suzuki, Toshiaki; Niwa, Masaaki

    2014-12-01

    We fabricated a mesoscopic Si wire by introducing dislocations in a silicon wafer before HF anodization. The dislocations formed along the (111) crystal plane. The outline of the dislocation line was an inverted triangle. The resulting wire floated on a bridge girder and had a hybrid structure consisting of a porous layer and crystalline Si. The cross section of the wire had an inverted triangle shape. The wire formation mechanism is discussed in terms of carrier transport, crystal structure, and dislocation formation during anodization.

  20. Bilateral traumatic hip dislocation with sciatic nerve palsy.

    PubMed

    Fan, Ka Yuk; Lui, Tun Hing

    2015-01-01

    Bilateral hip dislocation is a rare condition. We report a case of traumatic bilateral hip dislocation and unilateral sciatic nerve palsy in a young woman with known idiopathic scoliosis. With prompt reduction of the dislocated hips, there was reasonable neurological recovery. There was no avascular necrosis of the femoral head or post-traumatic arthritis up to 3-year follow-up. The gender difference in incidence, as well as the predisposition of hip dislocation in scoliosis is discussed. In our case, the decreased femoral anteversion was the culprit. PMID:25809426

  1. Neglected isolated plantar dislocation of middle cuneiform : a case report

    PubMed Central

    Verma, Ashu; Sharma, Vinod Kumar; Batra, Sumit; Rohria, Mahender Singh

    2007-01-01

    Background Four cases of plantar dislocation of middle cuneiform have been reported in the english literature. All of them were fresh cases and treated with open reduction. We are reporting a case of neglected plantar dislocation of middle cuneiform which was treated with excision. Case presentation A farmer presented with a painful plantar dislocation of middle cuneiform bone after 9 months of injury. The bone was deformed and was excised by a plantar incision. It resulted in painless foot with no disability. Conclusion The neglected plantar dislocated middle cuneiform bone becomes deformed due to repeated weight bearing. The gap gets filled with Fibrous tissue. Excision of the cuneiform gives good results. PMID:17229316

  2. Dislocation dynamics modelling of radiation damage in thin films

    NASA Astrophysics Data System (ADS)

    Ferroni, Francesco; Tarleton, Edmund; Fitzgerald, Steven

    2014-06-01

    Transmission electron microscopy is a key tool for the extraction of information on radiation damage, the understanding of which is critical for materials development for nuclear fusion and fission reactors. Dislocations in TEM samples are subject to strong image forces, owing to the nanometric sample thicknesses, which may introduce artifacts in the damage analysis. Using dislocation dynamics, we elucidate the roles played by dislocation-surface interactions, dislocation-dislocation interactions and self-interactions due to climb for loop types observed in TEM. Comparisons with analytic solutions for a dislocation loop and an edge dislocation in a half-space are included, and the relationship between glide force and loop tilt examined. The parameters for convergence of the zero-traction boundary conditions are obtained, after which the evolution of dislocation structures in a thin film is studied. It is found that three main length scales govern the physical processes: the image force is governed by the distance of the loop from the surface and scales with the film thickness; the glide force is governed by the image stress as well as the loop-loop interaction stress which is in turn governed by the loop spacing L\\sim 1/\\sqrt{\\rho} , where ρ is the loop density; finally, the climb force depends on the loop size. The three forces compete and their relative magnitudes define the evolution pathway of the dislocation structure.

  3. [Bilateral elbow dislocation related to Essex-Lopresti injury].

    PubMed

    Romero Pérez, B; Marcos García, A; Medina Henríquez, J A; Muratore Moreno, G

    2012-01-01

    Elbow dislocation is second in frequency, after the shoulder, whereas bilateral dislocation is uncommon, even less than dislocations with concurrent associated fractures. One of the least frequent associations is the Essex-Lopresti injury which consists of a fracture of the radial head affecting the distal radioulnar joint with injury to the interosseous membrane. This is a case of bilateral elbow dislocation, one of the elbows associated with the Essex-Lopresti injury. During treatment, the premature closed reduction prevails, previously making sure the elbow is stable, the premise which will determine the orthopedic or surgical treatment of the injury. PMID:23177945

  4. Temperature and strain-rate dependence of surface dislocation nucleation.

    PubMed

    Zhu, Ting; Li, Ju; Samanta, Amit; Leach, Austin; Gall, Ken

    2008-01-18

    Dislocation nucleation is essential to the plastic deformation of small-volume crystalline solids. The free surface may act as an effective source of dislocations to initiate and sustain plastic flow, in conjunction with bulk sources. Here, we develop an atomistic modeling framework to address the probabilistic nature of surface dislocation nucleation. We show the activation volume associated with surface dislocation nucleation is characteristically in the range of 1-10b3, where b is the Burgers vector. Such small activation volume leads to sensitive temperature and strain-rate dependence of the nucleation stress, providing an upper bound to the size-strength relation in nanopillar compression experiments. PMID:18232884

  5. Interfacial dislocation motion and interactions in single-crystal superalloys

    SciTech Connect

    Liu, B.; Raabe, D.; Roters, F.; Arsenlis, A.

    2014-10-01

    The early stage of high-temperature low-stress creep in single-crystal superalloys is characterized by the rapid development of interfacial dislocation networks. Although interfacial motion and dynamic recovery of these dislocation networks have long been expected to control the subsequent creep behavior, direct observation and hence in-depth understanding of such processes has not been achieved. Incorporating recent developments of discrete dislocation dynamics models, we simulate interfacial dislocation motion in the channel structures of single-crystal superalloys, and investigate how interfacial dislocation motion and dynamic recovery are affected by interfacial dislocation interactions and lattice misfit. Different types of dislocation interactions are considered: self, collinear, coplanar, Lomer junction, glissile junction, and Hirth junction. The simulation results show that strong dynamic recovery occurs due to the short-range reactions of collinear annihilation and Lomer junction formation. The misfit stress is found to induce and accelerate dynamic recovery of interfacial dislocation networks involving self-interaction and Hirth junction formation, but slow down the steady interfacial motion of coplanar and glissile junction forming dislocation networks. The insights gained from these simulations on high-temperature low-stress creep of single-crystal superalloys are also discussed.

  6. Internal stresses in a homogenized representation of dislocation microstructures

    NASA Astrophysics Data System (ADS)

    Schmitt, Severin; Gumbsch, Peter; Schulz, Katrin

    2015-11-01

    To develop a continuum theory based on the evolution of dislocation microstructures, two challenges have to be resolved: the correct representation of the kinematics of dislocation motion in terms of dislocation density and the formulation of a mobility law reflecting an effective description of the physical behavior of the discrete many-body problem. Kröner's classical continuum theory has inspired different approaches to model plasticity based on the motion of dislocations. Amongst them, the Continuum Dislocation Dynamics (CDD) theory was formulated as a generalization of the classical theory. The CDD theory allows for a continuous representation of the evolution of dislocation microstructures and is found to be kinematically complete. Here, a numerical formulation of the CDD theory is presented and constitutive laws for the incorporation of dislocation interactions are derived based on the representation of the dislocation microstructure in two dimensions. An error measure is introduced to analyze the constitutive law and the results are compared to discrete dislocation dynamics simulations. Important aspects for the implementation of a 3D theory are discussed.

  7. Orientation dependence of shock induced dislocations in Tantalum single crystals

    NASA Astrophysics Data System (ADS)

    Pang, Bo; Jones, I.; Chiu, Yulung; Millett, J.; Whiteman, Glenn; Bourne, N.

    2013-06-01

    Shock wave deformation of monocrystalline tantalum to a pressure of 6.2 GPa and duration of 1.7 μs generates profuse dislocations. Three orientations (100),(110),(111) were tested to examine the orientation dependence of the dislocation generation. The dislocations were characterised by transmission electron microscopy. The difference in the Burgers vectors of the primary dislocations in the specimens with different orientations showed a distinct anisotropy and will be discussed in light of the models of slip behaviour in one-dimensional strain (Smith 1958) and (Meyers 1978). The front and rear surfaces of the specimens were both investigated to examine the effects of wave duration.

  8. [Hip dislocation. Organization of screening and follow-up].

    PubMed

    Abuamara, S; Dacher, J N; Gaucher, S; Lechevallier, J; Brossard, V; Delhaye, L; Durand, C; Levasseur, F; Henocq, A

    1999-06-01

    Early detection and low-risk treatment are the two main objectives of the management of developmental dislocation of the hip. The best way to evaluate neonatal hips is to perform clinical and ultrasound examinations at the same time, and to confront their results. Early diagnosis allows to restrict treatment to infants with neonatal dislocation who do not improve by 4 weeks of age. On the other hand, neonates with reductible dislocated hips must be treated at birth and followed at the joint consultation. Early diagnosis and management must not decrease later efforts to detect dislocated hip until walking age. PMID:10394462

  9. Screw dislocation in a two-phase isotropic thin film

    NASA Astrophysics Data System (ADS)

    Chu, S. N. G.

    1982-04-01

    By using the complex potential and conformal mapping techniques, the stress field of a straight screw dislocation lying parallel to the surface of a two-phase isotropic thin film of equal thickness in each phase and a welded interface is analyzed. The solution, when reduced to a single-phase thin film, is in agreement with that derived by Liebfried and Dietze using an infinite array of image dislocations. The presence of a second phase is found to increase the magnitude of the stress components for the screw dislocation except for τxz near the interface where the effect is the reverse. The image force on the dislocation near the interface can be attractive or repulsive depending upon whether the dislocation is situated in the hard or soft phase. In the case where the dislocation is situated in the soft phase, the total image force tends to drive the screw dislocation to the surface. Furthermore, the screw dislocation is found to be unstable at the interface. The elastic solution for an interfacial dislocation becomes a special case.

  10. Mobility of edge dislocations in stressed iron crystals during irradiation

    SciTech Connect

    Korchuganov, A. V. Zolnikov, K. P.; Kryzhevich, D. S.; Chernov, V. M.; Psakhie, S. G.

    2015-10-27

    The behavior of a/2(111)(110) edge dislocations in iron in shear loading and irradiation conditions was studied by means of molecular dynamics simulation. Edge dislocations were exposed to shock waves formed by atomic displacement cascades of different energies. It was shown that starting from a certain threshold amplitude shock waves cause displacement of edge dislocations in the loaded samples. Calculations showed that the larger the shear load and the amplitude of the shock wave, the greater the displacement of dislocations in the crystallite.

  11. Congenital dislocation of the patella – clinical case☆

    PubMed Central

    Miguel Sá, Pedro; Raposo, Filipa; Santos Carvalho, Manuel; Alegrete, Nuno; Coutinho, Jorge; Costa, Gilberto

    2015-01-01

    Congenital patellar dislocation is a rare condition in which the patella is permanently dislocated and cannot be reduced manually. The patella develops normally as a sesamoid bone of the femur. This congenital dislocation results from failure of the internal rotation of the myotome that forms the femur, quadriceps muscle and extensor apparatus. It usually manifests immediately after birth, although in some rare cases, the diagnosis may be delayed until adolescence or adulthood. Early diagnosis is important, thereby allowing surgical correction and avoiding late sequelae, including early degenerative changes in the knee. A case of permanent dislocation of the patella is presented here, in a female child aged seven years. PMID:26962496

  12. Dislocation luminescence in GaN single crystals under nanoindentation

    NASA Astrophysics Data System (ADS)

    Huang, Jun; Xu, Ke; Fan, Ying Min; Wang, Jian Feng; Zhang, Ji Cai; Ren, Guo Qiang

    2014-12-01

    This work presents an experimental study on the dislocation luminescence in GaN by nanoindentation, cathodoluminescence, and Raman. The dislocation luminescence peaking at 3.12 eV exhibits a series of special properties in the cathodoluminescence measurements, and it completely disappears after annealing at 500°C. Raman spectroscopy shows evidence for existence of vacancies in the indented region. A comprehensive investigation encompassing cathodoluminescence, Raman, and annealing experiments allow the assignment of dislocation luminescence to conduction-band-acceptor transition involving Ga vacancies. The nanoscale plasticity of GaN can be better understood by considering the dislocation luminescence mechanism.

  13. Dislocations in magnetohydrodynamic waves in a stellar atmosphere.

    PubMed

    López Ariste, A; Collados, M; Khomenko, E

    2013-08-23

    We describe the presence of wave front dislocations in magnetohydrodynamic waves in stratified stellar atmospheres. Scalar dislocations such as edges and vortices can appear in Alfvén waves, as well as in general magnetoacoustic waves. We detect those dislocations in observations of magnetohydrodynamic waves in sunspots in the solar chromosphere. Through the measured charge of all the dislocations observed, we can give for the first time estimates of the modal contribution in the waves propagating along magnetic fields in solar sunspots. PMID:24010425

  14. The Effects of Economic Policies and Employment Assistance Programs on the Well-Being of Displaced Female Apparel Workers

    ERIC Educational Resources Information Center

    Rocha, Cynthia; Strand, Elizabeth B.

    2004-01-01

    This article explores how labor market trends and current employment assistance policies affect reemployment opportunities and emotional well-being in a sample of female dislocated apparel workers. The study follows the displaced women from the time the plant closed for 6 months to assess their financial and emotional well-being as they reentered…

  15. [Has the duration of cast fixation after shoulder dislocations an influence on the frequency of recurrent dislocation? (author's transl)].

    PubMed

    Ehgartner, K

    1977-08-26

    102 primary shoulder dislocations have been evaluated. Some were retained in a Velpeau bandage reinforced with plaster immediately after reposition for three weeks, others were treated with a sling or tube gauze only. The frequency of recurrent dislocation in both groups was compared. It could be demonstrated that the results were equal for both groups. We conclude that fixation with Velpeau Sling and cast reinforcement does not significantly influence the occurrence of recurrent dislocations. PMID:907550

  16. Pseudoclimb and dislocation dynamics in superplastic nanotubes.

    PubMed

    Ding, Feng; Jiao, Kun; Wu, Mingqi; Yakobson, Boris I

    2007-02-16

    Plastic relaxation of carbon nanotubes under tension and at high temperature is described in terms of dislocation theory and with atomistic computer simulations. It is shown how the glide of pentagon-heptagon defects and a particular type of their pseudoclimb, with the atoms directly breaking out of the lattice, work concurrently to maintain the tube perfection. Derived force diagram quantifies the balance between these mechanisms, while simulations show both helical and longitudinal movement of the kinks, in agreement with the forces and with experimental observations. PMID:17359035

  17. Dislocation Mechanics of High-Rate Deformations

    NASA Astrophysics Data System (ADS)

    Armstrong, Ronald W.; Li, Qizhen

    2015-10-01

    Four topics associated with constitutive equation descriptions of rate-dependent metal plastic deformation behavior are reviewed in honor of previous research accomplished on the same issues by Professor Marc Meyers along with colleagues and students, as follow: (1) increasing strength levels attributed to thermally activated dislocation migration at higher loading rates; (2) inhomogeneous adiabatic shear banding; (3) controlling mechanisms of deformation in shock as compared with shock-less isentropic compression experiments and (4) Hall-Petch-based grain size-dependent strain rate sensitivities exhibited by nanopolycrystalline materials. Experimental results are reviewed on the topics for a wide range of metals.

  18. Arthroscopic fixation of type III acromioclavicular dislocations.

    PubMed

    Somers, Jan F A; Van der Linden, Dietert

    2007-10-01

    Type III Acromio-Clavicular Joint dislocations can be treated successfully by surgical stabilisation in situ, with or without reconstruction of the coracoclavicular ligaments. The authors describe a simple and reliable mode of fixation, performed arthroscopically. The technique can be used for in situ fixation, or as part of an arthroscopically assisted Weaver and Dunn procedure. Using a metallic anchor loaded with a braided polyfilament suture, a strong and reliable fixation of the clavicle to the coracoid process is obtained. No hardware removal is necessary. Concomitant glenohumeral pathology can be treated simultaneously. PMID:18019910

  19. [Acute perilunar dislocations: algorithm for treatment].

    PubMed

    Towfigh, H

    2001-01-01

    In most cases, perilunar dislocations of the wrist are caused by high speed accidents. Usually these injuries occur by a fall on the dorsiflexed superextension of the hand. The instability caused by injuries of various erticular structures (ligament, bone) show various developmental stages. Clinical symptoms are reduced and painful movement, instability of the carpus, snapping and swelling. The diagnosis is established by X-ray, cinematography, arthrography MRT or CT. Perilunar instability with or without associated fractures and particularly de Quervain must be reduced and treated operatively including suture of the ligament and stabilization of the fracture. PMID:11824286

  20. Organizing marginalized workers.

    PubMed

    Taylor, A K

    1999-01-01

    Figures from the U.S. Department of Labor show that low-wage or marginalized workers are more likely to be injured on the job and suffer more work-related medical conditions than better-paid workers. Despite an increasingly hostile organizing climate, market globalization, and corporate downsizing, significant progress has been made in organizing marginalized workers. A multifaceted, comprehensive organizing strategy, incorporating union-building strategies that include (but are not limited to) safety and health, must be used by unions to successfully organize marginalized workers and obtain the first contract. PMID:10378982

  1. Predictive Modeling in Adult Education

    ERIC Educational Resources Information Center

    Lindner, Charles L.

    2011-01-01

    The current economic crisis, a growing workforce, the increasing lifespan of workers, and demanding, complex jobs have made organizations highly selective in employee recruitment and retention. It is therefore important, to the adult educator, to develop models of learning that better prepare adult learners for the workplace. The purpose of…

  2. Migration and Adult Education

    ERIC Educational Resources Information Center

    Gois, William

    2007-01-01

    The objective of this paper is to highlight the role of adult education as a tool in addressing labour migration issues, specifically those concerning the protection of migrant workers' rights and the transformation of the impact of migration into positive holistic developmental gains. The view of labour migration as a means to forge the economic…

  3. Collective overcoming of point defects by dislocations in the dynamic region

    NASA Astrophysics Data System (ADS)

    Malashenko, V. V.

    2014-08-01

    A mechanism of collective overcoming of point defects by dislocations during the over-barrier slip has been proposed. It has been shown that the interaction between dislocations promotes the overcoming of point defects at a high dislocation density.

  4. Advanced worker protection system

    SciTech Connect

    Caldwell, B.; Duncan, P.; Myers, J.

    1995-12-01

    The Department of Energy (DOE) is in the process of defining the magnitude and diversity of Decontamination and Decommissioning (D&D) obligations at its numerous sites. The DOE believes that existing technologies are inadequate to solve many challenging problems such as how to decontaminate structures and equipment cost effectively, what to do with materials and wastes generated, and how to adequately protect workers and the environment. Preliminary estimates show a tremendous need for effective use of resources over a relatively long period (over 30 years). Several technologies are being investigated which can potentially reduce D&D costs while providing appropriate protection to DOE workers. The DOE recognizes that traditional methods used by the EPA in hazardous waste site clean up activities are insufficient to provide the needed protection and worker productivity demanded by DOE D&D programs. As a consequence, new clothing and equipment which can adequately protect workers while providing increases in worker productivity are being sought for implementation at DOE sites. This project will result in the development of an Advanced Worker Protection System (AWPS). The AWPS will be built around a life support backpack that uses liquid air to provide cooling as well as breathing gas to the worker. The backpack will be combined with advanced protective garments, advanced liquid cooling garment, respirator, communications, and support equipment to provide improved worker protection, simplified system maintenance, and dramatically improve worker productivity through longer duration work cycles. Phase I of the project has resulted in a full scale prototype Advanced Worker Protection Ensemble (AWPE, everything the worker will wear), with sub-scale support equipment, suitable for integrated testing and preliminary evaluation. Phase II will culminate in a full scale, certified, pre-production AWPS and a site demonstration.

  5. Implicit integration methods for dislocation dynamics

    SciTech Connect

    Gardner, D. J.; Woodward, C. S.; Reynolds, D. R.; Hommes, G.; Aubry, S.; Arsenlis, A.

    2015-01-20

    In dislocation dynamics simulations, strain hardening simulations require integrating stiff systems of ordinary differential equations in time with expensive force calculations, discontinuous topological events, and rapidly changing problem size. Current solvers in use often result in small time steps and long simulation times. Faster solvers may help dislocation dynamics simulations accumulate plastic strains at strain rates comparable to experimental observations. Here, this paper investigates the viability of high order implicit time integrators and robust nonlinear solvers to reduce simulation run times while maintaining the accuracy of the computed solution. In particular, implicit Runge-Kutta time integrators are explored as a way of providing greater accuracy over a larger time step than is typically done with the standard second-order trapezoidal method. In addition, both accelerated fixed point and Newton's method are investigated to provide fast and effective solves for the nonlinear systems that must be resolved within each time step. Results show that integrators of third order are the most effective, while accelerated fixed point and Newton's method both improve solver performance over the standard fixed point method used for the solution of the nonlinear systems.

  6. Implicit integration methods for dislocation dynamics

    DOE PAGESBeta

    Gardner, D. J.; Woodward, C. S.; Reynolds, D. R.; Hommes, G.; Aubry, S.; Arsenlis, A.

    2015-01-20

    In dislocation dynamics simulations, strain hardening simulations require integrating stiff systems of ordinary differential equations in time with expensive force calculations, discontinuous topological events, and rapidly changing problem size. Current solvers in use often result in small time steps and long simulation times. Faster solvers may help dislocation dynamics simulations accumulate plastic strains at strain rates comparable to experimental observations. Here, this paper investigates the viability of high order implicit time integrators and robust nonlinear solvers to reduce simulation run times while maintaining the accuracy of the computed solution. In particular, implicit Runge-Kutta time integrators are explored as a waymore » of providing greater accuracy over a larger time step than is typically done with the standard second-order trapezoidal method. In addition, both accelerated fixed point and Newton's method are investigated to provide fast and effective solves for the nonlinear systems that must be resolved within each time step. Results show that integrators of third order are the most effective, while accelerated fixed point and Newton's method both improve solver performance over the standard fixed point method used for the solution of the nonlinear systems.« less

  7. Implicit integration methods for dislocation dynamics

    NASA Astrophysics Data System (ADS)

    Gardner, D. J.; Woodward, C. S.; Reynolds, D. R.; Hommes, G.; Aubry, S.; Arsenlis, A.

    2015-03-01

    In dislocation dynamics simulations, strain hardening simulations require integrating stiff systems of ordinary differential equations in time with expensive force calculations, discontinuous topological events and rapidly changing problem size. Current solvers in use often result in small time steps and long simulation times. Faster solvers may help dislocation dynamics simulations accumulate plastic strains at strain rates comparable to experimental observations. This paper investigates the viability of high-order implicit time integrators and robust nonlinear solvers to reduce simulation run times while maintaining the accuracy of the computed solution. In particular, implicit Runge-Kutta time integrators are explored as a way of providing greater accuracy over a larger time step than is typically done with the standard second-order trapezoidal method. In addition, both accelerated fixed point and Newton's method are investigated to provide fast and effective solves for the nonlinear systems that must be resolved within each time step. Results show that integrators of third order are the most effective, while accelerated fixed point and Newton's method both improve solver performance over the standard fixed point method used for the solution of the nonlinear systems.

  8. Efficient time integration in dislocation dynamics

    NASA Astrophysics Data System (ADS)

    Sills, Ryan B.; Cai, Wei

    2014-03-01

    The efficiencies of one implicit and three explicit time integrators have been compared in line dislocation dynamics simulations using two test cases: a collapsing loop and a Frank-Read (FR) source with a jog. The time-step size and computational efficiency of the explicit integrators is shown to become severely limited due to the presence of so-called stiff modes, which include the oscillatory zig-zag motion of discretization nodes and orientation fluctuations of the jog. In the stability-limited regime dictated by these stiff modes, the implicit integrator shows superior efficiency when using a Jacobian that only accounts for short-range interactions due to elasticity and line tension. However, when a stable dislocation dipole forms during a jogged FR source simulation, even the implicit integrator suffers a substantial drop in the time-step size. To restore computational efficiency, a time-step subcycling algorithm is tested, in which the nodes involved in the dipole are integrated over multiple smaller, local time steps, while the remaining nodes take a single larger, global time step. The time-step subcycling method leads to substantial efficiency gain when combined with either an implicit or an explicit integrator.

  9. Concept of healing of recurrent shoulder dislocation.

    PubMed

    D'Angelo, Donato

    2014-01-01

    This paper presents the main surgical techniques applied in the treatment of anterior recurrent shoulder dislocation, aiming the achievement of the normality of articulate movements. This was obtained by combining distinct surgical procedures, which allowed the recovery of a complete functional capacity of the shoulder, without jeopardizing the normality of movement, something that has not been recorded in the case of the tense sutures of the surgical procedures of Putti-Platt, Bankart, Latarjet, Dickson-O'Dell and others. The careful review of the methods applied supports the conclusion that recurrent shoulder dislocation can be cured, since cure has been obtained in 97% of the treated cases. However, some degree of limitation in the shoulder movement has been observed in most of the treated cases. Our main goal was to achieve a complete shoulder functional recovery, by treating simultaneously all of the anatomical-pathological lesions, without considering the so-called essential lesions. The period of post-operatory immobilization only last for the healing of soft parts; this takes place in a position of neutral shoulder rotation, since the use of vascular bone graft eliminates the need for long time immobilization, due to the shoulder stabilization provided by rigid fixation of the coracoid at the glenoid edge, as in the Latarjet's technique. Our procedure, used since 1959, comprises the association of several techniques, which has permitted shoulder healing without movement limitation. That was because of the tension reduction in the sutures of the subescapularis, capsule, and coracobraquialis muscles. PMID:26229839

  10. Extensor Mechanism Disruption in Knee Dislocation.

    PubMed

    O'Malley, Michael; Reardon, Patrick; Pareek, Ayoosh; Krych, Aaron; Levy, Bruce A; Stuart, Michael J

    2016-05-01

    Disruption of the knee extensor mechanism is a challenging injury with no clear consensus on optimal treatment. Although rare in the setting of knee dislocations, these injuries should not be overlooked. Acute, complete rupture of either the quadriceps or patellar tendon necessitates primary repair with or without augmentation. Surgical management may also be required in the setting of a partial tear if a significant extensor lag is present or nonoperative treatment has failed. Tendon augmentation is used during primary repair if the native tissue is inadequate or after a failed primary repair. The purpose of this study is to evaluate extensor mechanism disruption incidence, injury patterns, associated injuries, and surgical options, including a novel tendon augmentation technique. This procedure consists of primary patellar or quadriceps tendon repair with semitendinosus autograft augmentation utilizing a distal or proximal patellar socket. Advantages of repair with tendon augmentation include accelerated rehabilitation, decreased risk of patellar fracture from transverse or longitudinal bone tunnels, and less hardware complications. We recommend consideration of this technique for selected cases of acute extensor mechanism disruption in the setting of tibiofemoral dislocation. PMID:26636488

  11. [Dislocation of the clavicle: case report].

    PubMed

    Paša, L; Kalandra, S

    2011-01-01

    A traumatic dislocation of the clavicle is a rare injury. So far 37 reports of this trauma have been found in the relevant literature; they are most often treated by surgery. A 32-year-old woman was admitted to local hospital for polytraumata sustained in a motor car accident. Once the patient had been stabilised, at three months after injury, stabilisation of the left dislocated clavicle was undertaken. The medial end was stabilised, using a strip dissected from the ligament of the sternoclavicular (SC) joint capsule, with Orthocord sutures, and laterally by coracoacromial ligament transfer (Weaver and Dunn technique) and K-wire fixation through the acromioclavicular (AC) articulation. The K-wire was removed 10 weeks after stabilisation. At 6 months after the repair surgery, the patient was free of any complaint, with no motion restriction and with good configuration of the SC and AC joints. The mean scores according to the University of California at Los Angeles (UCLA) rating system were 14 points before surgery and 28 points at 6 months after surgery; the mean Constant scores were 56 and 92 at the respective intervals. The clinical outcome of surgical stabilisation in this patient was very good. She had no signs of instability and no restriction of motion at the joints treated. PMID:21575562

  12. A Fatal Misunderstanding in Liberal Adult Education: A Response to Oskar Negt.

    ERIC Educational Resources Information Center

    Hake, Barry J.

    2000-01-01

    This reassessment of an earlier article examines the politics of modernity and emergence of "life politics," the dislocation of the learning subject, and the need to reconsider liberal adult education in light of the Learning Society. (SK)

  13. Dynamics of discrete screw dislocations on glide directions

    NASA Astrophysics Data System (ADS)

    Alicandro, R.; De Luca, L.; Garroni, A.; Ponsiglione, M.

    2016-07-01

    We consider a simple discrete model for screw dislocations in crystals. Using a variational discrete scheme we study the motion of a configuration of dislocations toward low energy configurations. We deduce an effective fully overdamped dynamics that follows the maximal dissipation criterion introduced in Cermelli and Gurtin (1999) and predicts motion along the glide directions of the crystal.

  14. CT evaluation of tarsometatarsal fracture-dislocation injuries

    SciTech Connect

    Goiney, R.C.; Connell, D.G.; Nichols, D.M.

    1985-05-01

    Fracture-dislocation in the tarsometatarsal region (Lisfranc) may be subtle and difficult to recognize on standard radiographic projections. Computed tomography (CT) was used to study the normal anatomy of the forefoot and to evaluate three patients with suspected tarsometatarsal fracture dislocation. The advantages of CT in the evaluation of forefoot trauma are emphasized.

  15. Operative Treatment of Bipolar Clavicular Dislocation: A Case Report

    PubMed Central

    Schuh, Alexander; Thonse, Chirag Narayana; Schmickal, Thomas; Kleine, Ludwig

    2012-01-01

    Introduction: Simultaneous bipolar dislocation of the clavicle is uncommon and unusual, although it has been documented as panclavicular dislocation, floating clavicle, and complete dislocation of the clavicle. A review of the recent literature indicated that most bipolar clavicular dislocations have been treated non-operatively. Case Report: We report the case of a 23 year polytrauma patient with bipolar dislocation of the right clavicle. Patient presented to us 2 weeks post injury and had an unstable corao-clavicular joint. On radiographic assessment a simultaneous dislocation of the coraco-clavicular and sterno-clavicular joints of right side was diagnosed. In view of the unstable condition of the right clavicle, young age of the patient, requirement of high physical activity a decision for operative treatment for clavicle dislocation was taken. Patient was treated surgically with open reduction and tension band wiring with good result. Conclusion: Although bipolar dislocation of the clavicle are rare a high index of suspicion will avoid missed diagnosis. Open reduction and internal fixation is a good option in young patients and gives good short term result.

  16. Effective mobility of dislocations from systematic coarse-graining

    NASA Astrophysics Data System (ADS)

    Kooiman, M.; Hütter, M.; Geers, MGD

    2015-06-01

    The dynamics of large amounts of dislocations governs the plastic response of crystalline materials. In this contribution we discuss the relation between the mobility of discrete dislocations and the resulting flow rule for coarse-grained dislocation densities. The mobilities used in literature on these levels are quite different, for example in terms of their intrinsic the stress dependence. To establish the relation across the scales, we have derived the macroscopic evolution equations of dislocation densities from the equations of motion of individual dislocations by means of systematic coarse-graining. From this, we can identify a memory kernel relating the driving force and the flux of dislocations. This kernel can be considered as an effective macroscopic mobility with two contributions; a direct contribution related to the overdamped motion of individual dislocations, and an emergent contribution that arises from time correlations of fluctuations in the Peach-Koehler force. Scaling analysis shows that the latter contribution is dominant for dislocations in metals at room temperature. We also discuss several concerns related to the separation of timescales.

  17. A field theory of piezoelectric media containing dislocations

    SciTech Connect

    Taupin, V. Fressengeas, C.; Ventura, P.; Lebyodkin, M.

    2014-04-14

    A field theory is proposed to extend the standard piezoelectric framework for linear elastic solids by accounting for the presence and motion of dislocation fields and assessing their impact on the piezoelectric properties. The proposed theory describes the incompatible lattice distortion and residual piezoelectric polarization fields induced by dislocation ensembles, as well as the dynamic evolution of these fields through dislocation motion driven by coupled electro-mechanical loading. It is suggested that (i) dislocation mobility may be enhanced or inhibited by the electric field, depending on the polarity of the latter, (ii) plasticity mediated by dislocation motion allows capturing long-term time-dependent properties of piezoelectric polarization. Due to the continuity of the proposed electro-mechanical framework, the stress/strain and polarization fields are smooth even in the dislocation core regions. The theory is applied to gallium nitride layers for validation. The piezoelectric polarization fields associated with bulk screw/edge dislocations are retrieved and surface potential modulations are predicted. The results are extended to dislocation loops.

  18. A Case of Simultaneous Bilateral Anterior Shoulder Dislocation

    PubMed Central

    Patil, Mallanagouda N

    2013-01-01

    Introduction: Anterior dislocation of shoulder is commonest dislocation one encounters in day to day Orthopaedic practice. But bilateral shoulder dislocations are relatively uncommon frequently posterior and secondary to violent muscle contraction. Simultaneous bilateral anterior dislocations of shoulder following trauma is rare occurrence. Case Report: 35 year old male presented to emergency department with history fall by tripping on a stone (fall on outstretched hand). He complained of pain and difficulty in moving both the shoulders. On clinical examination, patient's both upper limbs were abducted and externally rotated. Bilaterally shoulder contour was lost with flattening. Other classical signs of shoulder dislocation viz, Bryants test, Callway sign, Hamilton's ruler test were positive. Diagnosis was confirmed on X rays. Both shoulders were reduced in emergency operation theater under general anaesthesia by Kocher's method and were immobilised in sling. Conclusion: Though bilateral shoulder dislocations are commonly posterior, usually either secondary to convulsions or electric shock, anterior dislocation has to be kept in mind , especially in post traumatic injuries. This bilateral dislocation also presents with practical problems immobilization and day to day care of patients. PMID:27298905

  19. Computation of the lattice Green function for a dislocation

    NASA Astrophysics Data System (ADS)

    Tan, Anne Marie Z.; Trinkle, Dallas R.

    2016-08-01

    Modeling isolated dislocations is challenging due to their long-ranged strain fields. Flexible boundary condition methods capture the correct long-range strain field of a defect by coupling the defect core to an infinite harmonic bulk through the lattice Green function (LGF). To improve the accuracy and efficiency of flexible boundary condition methods, we develop a numerical method to compute the LGF specifically for a dislocation geometry; in contrast to previous methods, where the LGF was computed for the perfect bulk as an approximation for the dislocation. Our approach directly accounts for the topology of a dislocation, and the errors in the LGF computation converge rapidly for edge dislocations in a simple cubic model system as well as in BCC Fe with an empirical potential. When used within the flexible boundary condition approach, the dislocation LGF relaxes dislocation core geometries in fewer iterations than when the perfect bulk LGF is used as an approximation for the dislocation, making a flexible boundary condition approach more efficient.

  20. Moment tensors of a dislocation in a porous medium

    NASA Astrophysics Data System (ADS)

    Wang, Zhi; Hu, Hengshan

    2016-06-01

    A dislocation can be represented by a moment tensor for calculating seismic waves. However, the moment tensor expression was derived in an elastic medium and cannot completely describe a dislocation in a porous medium. In this paper, effective moment tensors of a dislocation in a porous medium are derived. It is found that the dislocation is equivalent to two independent moment tensors, i.e., the bulk moment tensor acting on the bulk of the porous medium and the isotropic fluid moment tensor acting on the pore fluid. Both of them are caused by the solid dislocation as well as the fluid-solid relative motion corresponding to fluid injection towards the surrounding rocks (or fluid outflow) through the fault plane. For a shear dislocation, the fluid moment tensor is zero, and the dislocation is equivalent to a double couple acting on the bulk; for an opening dislocation or fluid injection, the two moment tensors are needed to describe the source. The fluid moment tensor only affects the radiated compressional waves. By calculating the ratio of the radiation fields generated by unit fluid moment tensor and bulk moment tensor, it is found that the fast compressional wave radiated by the bulk moment tensor is much stronger than that radiated by the fluid moment tensor, while the slow compressional wave radiated by the fluid moment tensor is several times stronger than that radiated by the bulk moment tensor.