Hydrodynamic air lubricated compliant surface bearing for an automotive gas turbine engine. 2: Materials and coatings

Material coatings for an air-lubricated, compliant journal bearing for an automotive gas turbine engine were exposed to service test temperatures of 540 C or 650 C for 300 hours, and to 10 temperature cycles from room temperatures to the service test temperatures. Selected coatings were then put on journal and partial-arc foils and tested in start-stop cycle tests at 14 kPa (2 psi) loading for 2000 cycles. Half of the test cycles were performed at a test chamber service temperature of 540 C (1000 F) or 650 C (1200 F); the other half were performed at room temperature. Based on test results, the following combinations and their service temperature limitations are recommended: HL-800 TM (CdO and graphite) on foil versus chrome carbide on journal up to 370 C (700 F); NASA PS 120 (Tribaloy 400, silver and CaF2 on journal versus uncoated foil up to 540 C (1000 F); and Kaman DES on journal and foil up to 640 C (1200 F). Kaman DES coating system was further tested successfully at 35 kPa (5 psi) loading for 2000 start-stop cycles

Subject Specific Computational Models of the Knee to Predict Anterior Cruciate Ligament Injury

Knee joint is a complex joint involving multiple interactions between cartilage, bone, muscles, ligaments, tendons and neural control. Anterior Cruciate Ligament (ACL) is one ligament in the knee joint that frequently gets injured during various sports or recreational activities. ACL injuries are common in college level and professional athletes especially in females and the injury rate is growing in epidemic proportions despite significant increase in the research focusing on neuromuscular and proprioceptive training programs. Most ACL injuries lead to surgical reconstruction followed by a lengthy rehabilitation program impacting the health and performance of the athlete. Furthermore, the athlete is still at the risk of early onset of osteoarthritis. Regardless of the gender disparity in the ACL injury rates, a clear understanding of the underlying injury mechanisms is required in order to reduce the incidence of these injuries. Computational modeling is a resourceful and cost effective tool to investigate the biomechanics of the knee. The aim of this study was twofold. The first aim was to develop subject specific computational models of the knee joint and the second aim to gain an improved understanding of the ACL injury mechanisms using the subject specific models. We used a quasi-static, multi-body modeling approach and developed MRI based tibio-femoral computational knee joint models. Experimental joint laxity and combined loading data was obtained using five cadaveric knee specimens and a state-of-the-art robotic system. Ligament zero strain lengths and insertion points were optimized using joint laxity data. Combined loading and ACL strain data were used for model validations. ACL injury simulations were performed using factorial design approach comprising of multiple factors and levels to replicate a large and rich set of loading states. This thesis is an extensive work covering all the details of the ACL injury project explained above and highlighting the importance of 1) computational modeling in inj

Subject Specific Computational Models of the Knee to Predict Anterior Cruciate Ligament Injury

Knee joint is a complex joint involving multiple interactions between cartilage, bone, muscles, ligaments, tendons and neural control. Anterior Cruciate Ligament (ACL) is one ligament in the knee joint that frequently gets injured during various sports or recreational activities. ACL injuries are common in college level and professional athletes especially in females and the injury rate is growing in epidemic proportions despite significant increase in the research focusing on neuromuscular and proprioceptive training programs. Most ACL injuries lead to surgical reconstruction followed by a lengthy rehabilitation program impacting the health and performance of the athlete. Furthermore, the athlete is still at the risk of early onset of osteoarthritis. Regardless of the gender disparity in the ACL injury rates, a clear understanding of the underlying injury mechanisms is required in order to reduce the incidence of these injuries. Computational modeling is a resourceful and cost effective tool to investigate the biomechanics of the knee. The aim of this study was twofold. The first aim was to develop subject specific computational models of the knee joint and the second aim to gain an improved understanding of the ACL injury mechanisms using the subject specific models. We used a quasi-static, multi-body modeling approach and developed MRI based tibio-femoral computational knee joint models. Experimental joint laxity and combined loading data was obtained using five cadaveric knee specimens and a state-of-the-art robotic system. Ligament zero strain lengths and insertion points were optimized using joint laxity data. Combined loading and ACL strain data were used for model validations. ACL injury simulations were performed using factorial design approach comprising of multiple factors and levels to replicate a large and rich set of loading states. This thesis is an extensive work covering all the details of the ACL injury project explained above and highlighting the importance of 1) computational modeling in inj

Evidence of Itinerant Ferromagnetism in Transition Metal Doped ZnO Nanostructures

This work is aimed at synthesizing and characterizing transition metals (Mn, Fe and Ni) doped ZnO nanostructures. The samples have been prepared by chemical co-precipitation method. The samples have been divided and one half has been coated SiO2. X-Ray diffraction indicated the formation of single phase ZnO. Optical and photoluminescence studies have been carried out using UV-Vis spectroscopy and Photoluminescence spectroscopy respectively. Magnetic responses of the samples have been studied using SQUID. The structural studies revealed that sample is having wurzite structure at room temperature. Magnetization results shows the ferromagnetism in 2 Fe doped, 5 Ni doped and 2 Mn doped ZnO. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3102

FORMULATION AND EVALUATION OF OPHTHALMIC GEL BASED ON DRUG-POLYMER-POLYMER TERNARY INTERACTION

 Objective: The objective was to enhance the amount of active substance reaching the target tissue or exerting a local effect in the cul-de-sac, theapproach we use is the application of in-situ gelling systems or phase transition systems, which are instilled in a liquid form and shift to a gel or solidphase in the cul-de-sac. The present study will focus on the development of formulation of ophthalmic gels. The polymer physicochemical propertieswere studied for the improvement in gel characteristics.Methods: The formulations were varied by the amount of the anionic and cationic polymer concentration. The 10 and 20-fold excess anionic polymerwere used. The 10 and 20-fold excess anionic polymer were used. Further cationic polymers were utilized to see any ternary interaction betweendrug and polymers.Results: From the present study it could be shown that most of the formulations were isotropic and could be clearly separated from the anisotropicones which were situated at the cationic side of the phase diagram only as well as at 10% polyvinyl alcohol. Furthermore, excess 20HA, 10PAA, and20PAA as well as HCS (HCS/20PAA) contributes to improve drug release control.Conclusion: The above formulation of were found to be quite stable and useful in the novel format of sol-gel transformations. Further, the physicalcharacteristics gels show better tolerability with anionic and cationic polymer.Keywords: Cationic, Anionic, Poloxamer, Sol-gel

ESTIMATION OF THE DRUG-DRUG AND DRUG-POLYMER OPHTHALMIC COMPLEX AT STOICHIOMETRY BY TERNARY PHASE BEHAVIOUR

Objective: The study focus on the drug-drug and drug-polymer interaction and their estimation at stoichiometry when such systems were formed. In this discovery we tried to make use of the latest research and novel concepts to explore the drug-polymer-polymer Ionic ternary InteractionMethods: Partial ternary phase diagrams were constructed and the stoichiometry of the ciprofloxacin/anionic polymer interaction was assessed in distilled water by means of dialysis equilibrium. The polymers were completely hydrated in distilled water by gentle stirring at room temperature and studied for viscosity and turbidimetric measurements.Results: Comparing the partial ternary phase diagrams of the different anionic to each other. PAA exhibited the largest gel area even with low polymer content. The anionic polymers HA and PAA showed good capability to interact with the drug giving soluble drug/polymer complexes; moreover they were able to form polymer/polymer complexes with Poloxamer and HCS, with a stoichiometry depending on the polymers involved.Conclusion: From the results of the present study, it can be concluded that formulations were made isotonic and favours corneal permeation of both the drug. Ocular Irritancy denotes formulations were quite stable & useful in novel format of sol-gel transformations.Â