Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 26 for “"Mechanical efficiency"”.
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Enhanced engine mechanical efficiency through tailoring of lubricant formulations to localized power cylinder wall conditions
Numerical and experimental studies were performed on an internal combustion engine power cylinder wall's lubricating oil film in order to assess the possibility of tailoring engine lubricants to specific engine configurations and operating conditions for significantly enhanced fuel economy without …
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Variations in pedalling technique of competitive cyclists: the effect on biological efficiency
The efficiency of pedalling technique has been a source of controversy amongst exercise scientists, coaches and cyclists for over 100 years. Biomechanically, it has been shown that orienting the pedal tangentially to the direction of motion of the crank provides the greatest force effectiveness. …
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Extending the performance of net shape molded fiber reinforced polymer composite valves for use in internal combustion engines
… engines, this may enable increased power and mechanical efficiency. Previously published work on FRC engine valves has both shown structural and thermal limitations.
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Nuove osservazioni sulla biomeccanica dell’uretere umano
… organ wall. Alterations of static and dynamic biomechanical properties of the ureteral wall lead to pathological states compromising regular urine transportation to bladder. Although knowledge on ureteral motility has advanced considerably, the molecular contractile mechanism of ureteral smooth …
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Diabetes and the Female Heart
… cross-bridge heat, force length work output, and mechanical efficiency between males and females. Second, I investigated to establish a type 2 diabetes model in both sexes using a high-fat diet and low-dose streptozotocin injections. Third, using the work-loop calorimeter, I studied isolated …
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Design and analysis of a modified power-split continuously variable transmission
… The power split CVPST has a potentially higher mechanical efficiency than a conventional shaft-to-shaft CVT, but it is unknown whether that efficiency can be improved. For the CVPST, the branch control circuit that contains the CVT can be disengaged at the ring gear for a 1:1 overall …
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Enhanced engine efficiency through subsystem lubricant viscosity investigations
… to investigate the potential benefits in fuel efficiency, engine emissions, lubricant longevity, and engine durability. Two experimental testing platforms were designed and implemented to empirically study the effects of lubricant formulations on the internal combustion engine's frictional …
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Development, Analysis, and Comparison of Electromechanical Properties and Electrode Morphology of Ionic Polymer Metal Composites
… and the current consumption to prove the electro-mechanical efficiency of the platinum, gold and Bucky paper IPMC. By studying the electromechanical properties of this smart composite actuator based on its actuation under different electric excitations, we can draw conclusions subsequently from …
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Large Strain Finite Element Analysis of Spinodal Shell Structures
… but often suffer from localized failure and low mechanical efficiency. Architectures derived from spinodal decomposition have promising material properties due to their continuous doubly curved surfaces with minimal stress concentrations. In this work, finite element analysis was used to model …
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Design and development of an extended range electric bywire/wireless hybrid vehicle with a near wheel motor drivetrain
… bed. The developed setup eliminates nearly all mechanical inefficiencies in the rear wheel drive transaxle drivetrain. All controls have been purposely designed as a duplicate set to allow for full independent control of both rear wheels in a truly independent architecture. Along with the …
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Investigation of the Combustion, Emissions, and Engine Performance Characteristics of Cottonseed Biodiesel for use in Power Generation
… C100 being stable for a shorter period of time. Mechanical efficiency of ULSD was 83% and presented a 5% decrease for C100; while the overall efficiency was 36% for ULSD and 33% for C100 at 8 bar IMEP. The NOX for C100 was improved and presented an 11% decrease compared with ULSD. Unburned …
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Efficiency and Motor Skill Learning (Locomotion, Physical, Physiology, Evolution, Practice)
Improvements in mechanical efficiency (E%) and transport efficiency (cal/m/kg) with practice, were investigated using 5 physically fit adult male subjects crawling on a horizontal motor-driven treadmill at .76 m/s. E% was the ratio of the work output of individual limb segments, based on a link …
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Structural Design Inspired by the Multiscale Mechanics of the Lightweight and Energy Absorbent Cuttlebone
… investigate how such a remarkable mechanical efficiency is enabled by the multiscale structure of cuttlebone. Using the common cuttlefish, Sepia Officinalis, as a model system, we first conducted high-resolution synchrotron micro-computed tomography (µ-CT) and quantified the …
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Design and Construction of a High Pressure System for Evaluating Multiphase Twin-Screw Pumps
… horsepower electric motor provides the mechanical power for the pump. The test facility includes instrumentation and data acquisition equipment to monitor the pressures and temperatures at various points in the flow loop, as well as the flow rate and motor voltage of the pump. The …
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As global ambient temperatures continue to rise, with the highest recorded annual averages since 1850 being within the last ten years, problems emerge for species exhibiting temperature-dependent sex determination. This is the process by which the sex of an animal’s embryo is determined based on the temperature of environment in which it is incubated, which can result in skewed sex ratios within a population like in the case of the critically endangered Hawksbill Sea Turtles (Eretmochelys imbricata). Reportedly, 85-95% of Hawksbills sampled in the wild are currently female [3]. This sex-imbalance can negatively impact the species’ ability to procreate, leading to the potential for extinction. Currently, no viable, long-term solutions exist to effectively and safely cool sea turtle eggs while still keeping them within their natural habitat. This research proposes the creation of sea turtle egg incubators designed to achieve a temperature range that will produce a higher percentage of male hatchlings to help rectify this imbalance in habitats heavily affected by climate change. These incubators are designed to be affordable, easy to build and, most importantly, safe for the sea turtle eggs. Three-month-long temperature trials for the incubator were conducted in Jamaica with conservationist community partners at Oracabessa Bay Sea Turtle Project. Results showed that this incubator is not only easy to manufacture and use, but that it successfully regulates the temperature range in favor of more male hatchlings, while also increasing the emergence rate of the hatchlings from 70% in natural nests to over 80%. During one of the hottest months in Jamaica, the incubator, deployed without water changes, doubled the predicted percentage of males produced by natural nests. When provided with cool water changes the incubator quintupled this value. Throughout the months of August to October, the incubator achieved a temperature range that is predicted to produce 85-99% male hatchlings, thus counteracting the feminization phenomenon occurring in nature.
… medical implants, are versatile materials but mechanically inefficient due to their bending-dominated microstructure, leading to an exponential loss of stiffness and strength at low relative densities. Architected materials address this limitation through engineered microstructures that achieve …
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Predictive modelling of the form and development of bone fracture healing
… and computationally, respectively, based on mechanical stimuli induced by the relative motion between bone fragments. To argue this case, the following hypotheses are tested; 1) the relationship between temporal rate of bone healing, measured in terms of callus stiffening per week, and the …
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Investigating Extended Gamma-Ray Sources with ASTRI and CTAO: Observation, Analysis and Modelling
… excess count profiles. The results show that the mechanical efficiency of stellar winds influences the gamma-ray morphology, and that some of the extended sources observed by LHAASO may be consistent with a YMSC origin. In summary, the thesis has: validated the ASTRI analysis pipeline with …
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Investigating Extended Gamma-Ray Sources with ASTRI and CTAO: Observation, Analysis and Modelling
… excess count profiles. The results show that the mechanical efficiency of stellar winds influences the gamma-ray morphology, and that some of the extended sources observed by LHAASO may be consistent with a YMSC origin. In summary, the thesis has: validated the ASTRI analysis pipeline with …
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Needle-free injection nozzle geometry
… nozzle demonstrates at least a 7% increase in mechanical efficiency and a decrease in cavitation of two orders of magnitude from a commercial jet injection nozzle.
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Revealing complexities within flat-water kayaking: injury prevention and biomechanical analysis
… second portion of the thesis involved novel biomechanical analysis of kayaking on the water and on a kayaking-ergometer. It is the first objective description of the three dimensional movements of the kayak in the literature. Sprint and marathon paddlers performed a 180 metre time trial using an …
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