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You searched for +publisher:"AUT University" +contributor:("Kelly, Piaras"). Showing records 1 – 2 of 2 total matches.

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AUT University

1. Saeidi, Mehdi. Numerical and Experimental Investigation of a New Load-sharing Implant for Early-onset Knee Osteoarthritis .

Degree: AUT University

Knee osteoarthritis (OA) is one of the major causes of musculoskeletal impairment in adults. This disease is mainly characterised by progressive degeneration of the articular cartilage and, to date, there is no known cure for it. Initiation and progression of the OA pathology is associated with knee loading conditions. For younger, active patients with knee OA, common treatments include non-invasive options in order to manage symptoms before considering, as a last resort, the surgical options, in particular the gold standard treatment: knee replacement. Recently developed load-sharing implants could be considered as suitable options lying between the symptom management and invasive treatments. One such implant is comprised of femoral and tibial components, and removes excessive load through the knee joint by attachment to the medial side. This patient-specific implant would be suitable for early-onset knee osteoarthritis and can be used for younger active patients, as no major modification in the knee joint is required. This research aimed to study the influence of the implant on tibiofemoral joint contact mechanics and bone remodelling using numerical and experimental methods. To do so, Finite Element (FE) knee models and cadaver knee specimens were used. Initially, a FE model was used for conducting stress analysis in the cartilage, then to implement an adaptive bone remodelling method. Periprosthetic Bone Mineral Density (BMD) changes induced by this new implant were investigated in the femur and tibia for the first time. The surgical procedure as well as the effects of the implant on the joint space and contact pressure were also studied using cadaver specimens and accurate real-time pressure measurement sensors. A prototype of the implant was made based on a 3D model of the specimen reconstructed using MR images. Through numerical and experimental investigations, it was deduced that this new implant can increase the joint space and effectively reduce the load going through the medial compartment, without affecting greatly the periprosthetic bone density. Specifically, after attachment of the implant, the maximum von Mises stress and contact pressure experienced by the femoral cartilage were reduced by 40% and 35%, respectively. Also, in the medial compartments of the femur and tibia, bone mineral density increased by approximately 3.4% and 4.1%, respectively, and the density for the fixation holes of both bones increased by around 2.2%. Moreover, according to the experimental contact pressure measurements, the implant reduced the load on the medial side by approximately 18% under all loading conditions. The implant was attached to the bone with a smaller incision than that used for total knee replacement, and without any bone resection or damage to soft tissue. During flexion and extension of the knee specimen, the implant did not cause any hindrance. According to the above points, this implant can be considered to be a minimally invasive treatment, which might slow down progression of knee OA without any… Advisors/Committee Members: Ramezani, Maziar (advisor), Kelly, Piaras (advisor), Neitzert, Thomas (advisor).

Subjects/Keywords: Knee; Osteoarthritis; Implant; Cadaver; Minimally invasive; Bone remodelling

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Saeidi, M. (n.d.). Numerical and Experimental Investigation of a New Load-sharing Implant for Early-onset Knee Osteoarthritis . (Thesis). AUT University. Retrieved from http://hdl.handle.net/10292/12645

Note: this citation may be lacking information needed for this citation format:
No year of publication.
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16th Edition):

Saeidi, Mehdi. “Numerical and Experimental Investigation of a New Load-sharing Implant for Early-onset Knee Osteoarthritis .” Thesis, AUT University. Accessed August 23, 2019. http://hdl.handle.net/10292/12645.

Note: this citation may be lacking information needed for this citation format:
No year of publication.
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

Saeidi, Mehdi. “Numerical and Experimental Investigation of a New Load-sharing Implant for Early-onset Knee Osteoarthritis .” Web. 23 Aug 2019.

Note: this citation may be lacking information needed for this citation format:
No year of publication.

Vancouver:

Saeidi M. Numerical and Experimental Investigation of a New Load-sharing Implant for Early-onset Knee Osteoarthritis . [Internet] [Thesis]. AUT University; [cited 2019 Aug 23]. Available from: http://hdl.handle.net/10292/12645.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
No year of publication.

Council of Science Editors:

Saeidi M. Numerical and Experimental Investigation of a New Load-sharing Implant for Early-onset Knee Osteoarthritis . [Thesis]. AUT University; Available from: http://hdl.handle.net/10292/12645

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
No year of publication.


AUT University

2. Khanlari, Khashayar. Mechanical and Tribological Characterization of Nitinol 60 Parts Manufactured by Different Powder Metallurgy Processes .

Degree: AUT University

NiTinol 60 (60NiTi) is a Ni-rich NiTi alloy comprising approximately ~60 wt.% (55 at.%) Ni and ~40 wt.% (45 at.%) Ti. 60NiTi, when employed in a hardened state, displays outstanding properties. It exhibits excellent corrosion resistance and a high level of hardness, has a low elastic modulus and an extensive elastic range that imparts high mechanical contact load resilience. It is dimensionally stable, has good bio-compatibility, can be machined into precision components and is non-magnetic. This unique set of characteristics make the intermetallic 60NiTi suitable for a wide variety of applications in the marine, medical, aerospace and food processing industries. As an example, this alloy has recently been employed as a rolling element bearing material that is highly corrosion resistant and endures high levels of shock loads before experiencing any permanent deformation. This work investigates the possibility of using hardened 60NiTi in two other distinct areas of interest. For the first area of interest, the sliding wear performance of 60NiTi is compared to 440C steel. This type of steel has high tensile strength and Rockwell C hardness similar to 60NiTi and is conventionally considered as a wear resistant alloy for applications such as gears where contacting materials slide over each other. This research, apart from defining the conditions under which the responses of these alloys differ and answers questions which arise from testing, helps to understand the conditions under which 60NiTi is a suitable alloy as a wear resistant material in sliding conditions. Results obtained in this research, in addition to introducing 60NiTi as a material for load bearing applications other than rolling, will help the engineering community to properly apply this intermetallic in situations where materials slide over each other. Furthermore, findings obtained in this research give an insight into main wear mechanisms and mechanical properties and clarify the mechanisms that at a microscopic level cause damage in 60NiTi and generally NiTi alloys. In addition, recent studies showed that the addition of hafnium, even in low concentrations, provides benefits in terms of hardening treatment and phase stability in 60NiTi. These findings have led to consider NiTi-Hf alloy (~58 wt.% Ni-~39 wt.% Ti-~3 wt.% Hf) as a substitute or alternative for 60NiTi alloy. The exact composition by weight percent is 57.6 % Ni-39.2 % Ti-3.2 % Hf (54 at.% Ni- 45 at.%Ti-1 at.% Hf) and is designated as 58Ni39Ti-3Hf. Despite the positive interest in this alloy, direct comparisons of the sliding behavior of 58Ni-39Ti-3Hf and the forerunner 60NiTi alloy have not been made. This research evaluates and compares the sliding performance of 58Ni39Ti-3Hf with baseline 60NiTi to investigate the effect of Hf-addition and define the conditions under which 58Ni-39Ti-3Hf can be considered as an alternative to 60NiTi for sliding applications. Moreover, reasons behind the observed differences are investigated and discussed through different mechanical and microstructural… Advisors/Committee Members: Kelly, Piaras (advisor), Cao, Peng (advisor), Neitzert, Thomas (advisor), Ramezani, Maziar (advisor).

Subjects/Keywords: 60NiTi; Wear mechanisms; Sliding applications; Lubricated conditions; Porous structures

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Khanlari, K. (n.d.). Mechanical and Tribological Characterization of Nitinol 60 Parts Manufactured by Different Powder Metallurgy Processes . (Thesis). AUT University. Retrieved from http://hdl.handle.net/10292/12099

Note: this citation may be lacking information needed for this citation format:
No year of publication.
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16th Edition):

Khanlari, Khashayar. “Mechanical and Tribological Characterization of Nitinol 60 Parts Manufactured by Different Powder Metallurgy Processes .” Thesis, AUT University. Accessed August 23, 2019. http://hdl.handle.net/10292/12099.

Note: this citation may be lacking information needed for this citation format:
No year of publication.
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

Khanlari, Khashayar. “Mechanical and Tribological Characterization of Nitinol 60 Parts Manufactured by Different Powder Metallurgy Processes .” Web. 23 Aug 2019.

Note: this citation may be lacking information needed for this citation format:
No year of publication.

Vancouver:

Khanlari K. Mechanical and Tribological Characterization of Nitinol 60 Parts Manufactured by Different Powder Metallurgy Processes . [Internet] [Thesis]. AUT University; [cited 2019 Aug 23]. Available from: http://hdl.handle.net/10292/12099.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
No year of publication.

Council of Science Editors:

Khanlari K. Mechanical and Tribological Characterization of Nitinol 60 Parts Manufactured by Different Powder Metallurgy Processes . [Thesis]. AUT University; Available from: http://hdl.handle.net/10292/12099

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
No year of publication.

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