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ABSTRACT: This report results from a contract tasking University of Portsmouth as follows: The onset of high cycle fatigue (HCF) crack propagation in Ti- 6Al-4V will be studied under combined HCF/low cycle fatigue (LCF) loading conditions at elevated temperatures up to 350 deg C where creep stress ratcheting and environmental effects may arise. The study will be applied to a simulated mission-loading spectrum. SEM fractography metallography and crack closure measurements will be used to assess the mechanisms contributing to fatigue crack growth. The study will be carried out on corner crack (CN) square cross-section specimens of forged Ti-6Al-4V and on single edge cracked rolled plate specimens of the same alloy. Information previously obtained for this alloy at room temperature will provide a baseline for comparison.
03/2005;
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ABSTRACT: This article describes an incision which incorporates principles of both the Bunnell midlateral incision and the Bruner zig-zag. It allows rapid access to the volar aspect of the digit without sacrificing exposure or risking flexion contractures while maintaining an unviolated volar skin flap. In this study of 125 patients, 189 digital problems were treated, using the modified midlateral incision. Ages ranged from eleven months to seventy-one years. Complications following surgery were unrelated to the incision.
The Journal of Hand Surgery British & European Volume 07/1986; 11(2):195-7. · 0.04 Impact Factor
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ABSTRACT: The efficacy of a bacterin prepared from Chlamydia psittaci grown in mouse L-cells was compared to a similar bacterin prepared from C. psittaci grown in chicken embryos (CE). Both bacterins significantly reduced (P < 0.03) incidence of abortion and weak lambs compared to non-vaccinated control ewes. The L-cell bacterin elicited a greater antibody response than the CE bacterin (P < 0.03).
Veterinary Microbiology.
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ABSTRACT: This article describes an incision which incorporates principles of both the Bunnell midlateral incision and the Bruner zig-zag. It allows rapid access to the volar aspect of the digit without sacrificing exposure or risking flexion contractures while maintaining an unviolated volar skin flap. In this study of 125 patients, 189 digital problems were treated, using the modified midlateral incision. Ages ranged from eleven months to seventy-one years. Complications following surgery were unrelated to the incision.
The Journal of Hand Surgery: British & European Volume.
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ABSTRACT: The study aims to understand small crack growth behaviour in Ti–6Al–4V plate specimens after foreign object damage (FOD), under combined low and high cycle fatigue (LCF/HCF) loading conditions. The loading block studied represents one of the simplest loading sequences experienced by aero-engines and each block includes a single LCF cycle at a load ratio (R) of 0.01 with 1000 HCF cycles at R of 0.7 superimposed at peak load.In Part I of this paper, the experimental studies are described. FOD was simulated by firing a 3 mm hardened steel cube onto targeted specimens with an impact velocity of 200 m/s, leading to a blunt “V” notch in a flat surface. Microstructural features associated with the FOD damage, e.g. microcracks, were characterized by optical and scanning electronic microscopy. The microcracks were found to be preferred sites for subsequent crack propagation. The growths of these FOD-initiated small cracks under combined LCF/HCF loading were drastically different from the long-crack results obtained from corner-cracked specimens. Stress relief annealing was conducted on selected specimens to remove the residual stresses due to FOD. The results indicated that residual stresses significantly affected both the development of crack front shape and the fatigue life.
International Journal of Fatigue.
