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 373 for “"Screw"”.
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Clearance management in twin screw compressors
Although the performance of twin screw compressors is heavily dependent on the rotor clearances within them, chamber models, used as design aids, allow for the specification of their magnitude and distribution but do not account for how these may vary during operation, as a result of internal …
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Optimization of Pedicle Screw Depth in the Lumbar Spine: Biomechanical Characterization of Screw Stability and Pullout Strength
… of the biomechanical strength of lumbar pedicle screw fixation as it relates to screw sizing and placement. Biomechanical analyses examining ideal pedicle screw depth with current pedicle screw technology are limited. In the osteoporotic spine, optimized pedicle screw insertion depth may improve …
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Finite Element Representation of Bone-Screw Mechanics
… or arm. Fixation using locking plates and bone screws has become the treatment of choice; however, an overall complication rate of 49% has been reported, with 7.5% resulted from failure of the bone-screw interface. Accordingly, the purpose of the work presented in this thesis is to develop …
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Screw fixation of implants to the spine
Bone screws are used to fix various implants to the human spine. Screw fixation can be difficult in osteoporotic bone because of its reduced strength. This research aimed to investigate screw fixation techniques in the spine. A questionnaire study, representing British and Irish spine surgeons, …
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Supersonic self-similar screw-pinch plasma implosions
… current and an entrained axial magnetic field (screw-pinch). These solutions represent a complete generalization of previous works done on the Z-pinch and $\Theta$-pinch schemes. The solutions presented herein represent a screw-pinch plasma with a diffuse current profile. Four separate plasma …
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Flow field analysis of some mixing and conveying screw element regions, within a closely intermeshing, co-rotating twin-screw extruder.
… in the closely intermeshing, co-rotating twin-screw extruder (CICo-TSE). CICo-TSEs contain screw elements that convey material with a self-wiping action and are widely used for polymer compounding and blending. Of the different mixing modules contained within the CICo-TSE, the trilobal …
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Chopped and Screwed: The Impact of DJ Screw
Chopped and Screwed is style of music producing created by Robert Earl Davis Jr., known as “DJ Screw”, that refers to taking a track and altering it to produce a new sound that is slowed down, warped and/or played back again. This style would give birth to the unique sound of southern rap music in …
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Parametrization of Triple Screw Pumps for Aerospace Applications
<p>Triple Screw Pumps, a form of positive displacement pump, offer steady, high-pressure flow. In very small launch vehicles or upper stages turbopumps are not practical. This paper examines the performance of triple screw pumps to determine if they may serve as an alternative to turbopumps for use …
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Development of a multi-purpose twin-screw extruder
… countries in which mainly single process twin-screw extruders are used. This leaves a void for the development for a multi-purpose twin-screw extruder. This will enable companies to manufacture a greater diversity of products with one machine, not only in South Africa, but in the rest of Africa …
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Texturization of soy protein via twin-screw extrusion
… In this study, a Werner & Pfleiderer twin-screw extruder Model ZSK-30 was used to texturize defatted soy flour and soy protein concentrate. A cooled sheeting die was designed to enhance the texture integrity of the finished product. Rheological properties of extrudates were measured by …
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Performance prediction model for positive displacement helical screw flowmeters
… model was applied to a twin-screw type displacement flowmeter which uses two helical rotors which form separate pockets and allow the flow-rate of the fluid to be measured. Based on the general prediction model it was found that for this type of flowmeter mainly two …
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Screw image space and its application to robotic grasping
… thesis is devoted to the study and extension of screw image space and its application to kinematic restraint and robotic grasping. In the study of restraint and robotic grasping, problems arise in relation to how to map the conditions and requirements of restraint in a special representational …
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Screw piles as offshore foundations : Numerical and physical modelling
… foundation solutions. In this thesis, screw piles (helical piles) have been proposed as a potential innovative alternative foundation for offshore wind turbines in deeper water. This type of pile has been used widely as foundation and anchor for onshore projects due to their ability to …
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Modelling of screw compressor plant operation under intermittent conditions
… an experimental and analytical study of screw compressor plant operating under unsteady conditions. For this purpose a one-dimensional model of the processes within a compressor was used, based on the differential equations of conservation of mass and energy, extended to include other …
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Regime map development for co-rotating twin screw granulation
… focused on one of the main equipments – twin screw extruder and attempted to develop the regime maps and the granulation hypothesis for twin screw granulation. In order to compare the mechanism with high-shear granulation that has been studied [1], the same materials were chosen (MCC …
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Review of energy harvesting methods for twin screw extruders
… sensor networks for system monitoring. Twin screw extruders are a type of extrusion processing machinery and could benefit from a condition monitoring system. Implementing a condition monitoring system for a twin screw extruder can prevent wasting materials, producing unusable products, and …
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Design and Manufacturing of a Lead Screw Robotic Gripper
… drawbacks of the original gripper design a lead screw gripper is designed and then a prototype is manufactured. The process of manufacturing found that the gripper can be assembled by hand, it is strong and articulates smoothly. The drawbacks with the design are mainly from the size of the body …
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