نتایج جستجو برای: ceramic petrography
تعداد نتایج: 24512 فیلتر نتایج به سال:
PURPOSE OF THE STUDY Total hip arthroplasty increases the use of alternate bearings to prevent polyethylene wear as the number of younger and more active patients has drastically risen. We carried out a prospective randomized study, to assess and compare clinical results and radiological changes, serum-cobalt- and serum-aluminium-levels when metal-on-metal and ceramic-on-ceramic bearings are ap...
Fracture of a modern ceramic head component in total hip replacement is an uncommon but catastrophic complication. Hence, the occurrence of a second ceramic head fracture in the same hip replacement of an individual represents a perishingly rare event. We present the case as a means of highlighting potential risk factors for ceramic head fracture and suggest possible management strategies in su...
This study suggests that contemporary modular acetabular shell designs employing ceramic liners deform during implantation where acetabular bed under-reaming is employed. The liner retention strength did not degrade by comparison to non-deformed shells using ASTM static push-out methods. A larger question, however, is the influence of this deformation on liner retention strength over time when ...
We prove that for all but a certain number of abelian groups of order n the Davenport constant is at most nk + k − 1 for positive integers k ≤ 7. For groups of rank three we improve on the existing bound involving the Alon-Dubiner constant.
Ceramic/metal interfaces occur in a great number of important applications, such as ceramic/metal composites, microelectronics packaging, ceramic/metal seals, and so forth. Understanding the formation and evolution of such interfaces is therefore essential for the better design and optimization of these technologies. In this thesis, a methodology for the study of the thermochemical interactions...
BACKGROUND Previous studies regarding modular head-neck taper corrosion were largely based on cobalt chrome (CoCr) alloy femoral heads. Less is known about head-neck taper corrosion with ceramic femoral heads. QUESTIONS/PURPOSES We asked (1) whether ceramic heads resulted in less taper corrosion than CoCr heads; (2) what device and patient factors influence taper fretting corrosion; and (3) w...
Introduction: Dhofar 1428 is a lunar feldspathic breccia found in 2006. Bunch et al. [1] briefly described mineral chemistry of Dhofar 1428. Korotev and Zeigler [2] analyzed its bulk FeO and Sm compositions. Here, we report such detailed data for Dhofar 1428. Results and Discussion: Dhofar 1428 has a distinct breccia texture with numerous fragments of rock, mineral, and glass all welded by a gl...
GRA 06128 & 06129 are paired achondrites [1], with unique mineral proportions (75% oligoclase), mineral compositions, and oxygen isotope ratios. They appear to represent alkalic igneous rock from a hitherto unsampled differentiated parent body, modified significantly by thermal and shock metamorphism. Samples and Methods. Bulk samples were examined at JSC during splitting for consortium analyse...
The use of CAD/CAM technology has allowed the fabrication of ceramic restorations efficiently and with predictable results. Lithium disilicate is a type of glass ceramic material that can be used for the elaboration of laminate veneers, being monolithic restorations which require characterization through a covering ceramic in order to achieve acceptable esthetic results. The next case report sh...
Ceramic fractures have been reported to occur in hip replacements, but the techniques used to extract a well fixed but fractured component are not commonly described. We present a case of ceramic liner fracture and validate a modification of a previously reported extraction technique that allowed us to save the acetabular cup and insert a polyethylene liner. With an increasing trend in ceramic ...
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