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The Global ETD Search service is a free service for researchers
to find electronic theses and dissertations. This service is
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Networked Digital Library of Theses and Dissertations.
Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
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Showing 251 to 258 of 258 (0.038 seconds)Spelling suggestions: "subject:"compliant"" "subject:"ompliant""
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Experimental Investigation of a Closed Loop Impedance Pump with an Asymmetric WallGarg, Rachit 21 September 2018 (has links)
No description available.
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| 252 |
Development of Deployable Wings for Small Unmanned Aerial Vehicles Using Compliant MechanismsLandon, Steven D. 06 July 2007 (has links) (PDF)
Unmanned Air Vehicles (UAVs) have recently gained attention due to their increased ability to perform sophisticated missions with less cost and/or risk than their manned counterparts. This thesis develops approaches to the use of compliant mechanisms in the design of deployable wings for small UAVs. Although deployable wings with rigid-link mechanisms have been used in the past to maintain flight endurance while minimizing required storage volume, compliant mechanisms offer many advantages in manufacturability and potential space savings due to function sharing of components. A number of compliant, deployable wing concepts are generated and a classification system for them is formed. The pool of generated concepts serves as a basis for stimulating future concept ideas. A methodology is also proposed for evaluating concepts for a given application. The approach to developing compliant designs for certain applications is illustrated through two example designs, which demonstrate key portions of the proposed design process. Each is modeled and analyzed to demonstrate viability.
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| 253 |
Extending the security perimeter through a web of trust: the impact of GPS technology on location-based authentication techniquesAdeka, Muhammad I., Shepherd, Simon J., Abd-Alhameed, Raed January 2013 (has links)
No / Security is a function of the trust that is associated with the active variables in a system. Thus, the human factor being the most critical element in security systems, the security perimeter could be defined in relation to the human trust level. Trust level could be measured via positive identification of the person/device on the other side of the interaction medium, using various authentication schemes; location-based being one of the latest. As for the location-based services, the identity of a customer remains hazy as long as his location is unknown; he virtually remains a ghost in the air, with implications on trust. This paper reviews the various location-based authentication techniques with a focus on the role that GPS could play in optimising this authentication approach. It advocates the urgent need to make all transmission devices GPS-compliant as a way forward, despite the privacy issues that might arise.
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| 254 |
Design of Stochastic Neural-inspired Dynamical Architectures: Coordination and Control of Hyper-redundant RobotsHorchler, Andrew de Salle 31 May 2016 (has links)
No description available.
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| 255 |
Compliant Structures Facilitate Less Invasive and Biomechanically Improved Lumbar Spinal ImplantsOrr, Daniel J 19 November 2024 (has links) (PDF)
Implants used in lumbar spinal fusion and lumbar total disc replacement procedures have improved substantially over the years, however, the opportunity remains to improve either the adjustability, durability, motion, or minimally invasive characteristics which could aid in achieving optimal surgical outcomes. It is hypothesized that the inherent advantages of compliant mechanisms specifically Deployable Euler Spiral Connectors (DESCs) and a new mechanism known as the interior contact aided rolling element (I-CORE) are well suited for each of these applications and will be explored and utilized as the basis of these proposed designs. By addressing these challenges, the research endeavors to improve patient outcomes in both lumbar fusion and lumbar disc replacement procedures and advance the field of lumbar spinal surgery. Expandable cages, ideal for minimally invasive lumbar fusion, can be implanted in a compact form and then expanded. Differences in shape, size, material, and adjustability of cages are often overlooked. A systematic review revealed that design variations, such as rectangular titanium cages with medial-lateral and vertical expansion, and those with adjustable lordosis, are linked to better patient outcomes. Deployable Euler Spiral Connectors were leveraged to create an expandable fusion cage while also including recommended features from the systematic review. Finite element analysis, benchtop mechanical testing, and validation via in vitro device insertion were performed. The design highlights the potential of compliant mechanism devices for advancing minimally invasive lumbar fusion. A new compliant mechanism called the Interior Contact-Aided Rolling Element (I-CORE) is described and modeled using the pseudo-rigid-body method. The new mechanism included two degrees of rotational freedom at a tailorable stiffness combined with tailorable vertical compressibility and a mobile center of rotation. The model is outlined and validated using FEA and benchtop mechanical testing. The model is shown to be sufficiently accurate for initial design work. A novel motion preserving spinal implant using the I-CORE mechanism is described. Prototypes were manufactured from Ti6Al4V and validated using benchtop mechanical and in vitro biomechanical testing. Properties including compressive, shear, and torsional stiffness were quantified. The device was tested for expulsion and subsidence forces, showing results comparable to current devices. In vitro testing with human cadaveric lumbar segments demonstrated that the compliant interbody device maintained robust compressive, shear, and torsional strength, closely replicating the motion quality of intact segments when properly placed.
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| 256 |
The effects of contract modifications on Shari'ah compliant products in the United StatesWali-Uddin, Abdullah Mahdi 04 1900 (has links)
Islamic banking in the United States of America, became recognized as an
alternative to expand into the market of traditional Muslim consumers, living in
the United States. Because of strict regulatory guidelines, no Islamic banks
exist in the United States. Instead, conventional banks, Islāmic banking
windows (IBW) and other financial institutions offer Shari‘ah compliant products
by modifying classical Islamic contracts or attaching a rider to define contract
verbiage. This study reviewed techniques of adapting contracts used for
Shari‘ah compliant products in the United States to determine if the contracts
maintain the true characteristics of the original classical Islamic contracts.
Contracts in Islamic sacred law provide protections by ensuring wealth is not
wasted, and no injustice is performed by either of the contracting parties.
Wealth protection and justice are the inherit characteristics of contracts in the
Islāmic law. Any changes or modifications may void or decrease the protections
provided in Islamic law. This research reviewed the theoretical aspects of
contract modifications, by analyzing the procedures used for the derivative
Shari‘ah compliant product contracts used in the Islamic finance industry in
the United States. Data was evaluated and compared with the requirements of
classical Islamic contract equivalents, to determine the effects of these
changes. / Religious Studies and Arabic / D. Phil. (Religious Studies)
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| 257 |
Prediction and minimization of excessive distortions and residual stresses in compliant assembled structuresYoshizato, Anderson 26 May 2020 (has links)
The procedure of joining flexible or nonrigid parts using applied loads is called compliant assembly, and it is widely used in automotive, aerospace, electronics, and appliance manufacturing. Uncontrolled assembly processes may produce geometric errors that can exceed design tolerances and induce an increment of elastic energy in the structure due to the accumulation of internal stresses. This condition might create unexpected deformations and residual stress distributions across the structure that compromise product functionality. This thesis presents a method based on nonlinear Finite Element Analysis (FEA), metamodelling, and optimization techniques to provide accurate and on-time shimming strategies to support the definition of optimum assembly strategies. An example of the method on a typical aerospace wing box structure is demonstrated in the present study. The delivered outputs intend to support the production line by anticipating the response of the structure under a specific assembly condition and presenting alternative assembly strategies that can be applied to address eventual predicted issues on product requirements. / Graduate
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| 258 |
Achieving Complex Motion with Fundamental Components for Lamina Emergent MechanismsWinder, Brian Geoffrey 01 March 2008 (has links) (PDF)
Designing mechanical products in a competitive environment can present unique challenges, and designers constantly search for innovative ways to increase efficiency. One way to save space and reduce cost is to use ortho-planar compliant mechanisms which can be made from sheets of material, or lamina emergent mechanisms (LEMs). This thesis presents principles which can be used for designing LEMs. Pop-up paper mechanisms use topologies similar to LEMs, so it is advantageous to study their kinematics. This thesis outlines the use of planar and spherical kinematics to model commonly used pop-up paper mechanisms. A survey of common joint types is given, as well as an overview of common monolithic and layered mechanisms. In addition, it is shown that more complex mechanisms may be created by combining simple mechanisms in various ways. The principles presented are applied to the creation of new pop-up joints and mechanisms, which also may be used for lamina emergent mechanisms. Models of the paper mechanisms presented in Chapter 2 of the thesis are found in the appendix, and the reader is encouraged to print, cut out and assemble them. One challenge associated with spherical and spatial LEM design is creating joints with the desired motion characteristics, especially where complex spatial mechanism topologies are required. Hence, in addition to a study of paper mechanisms, some important considerations for designing joints for LEMs are presented. A technique commonly used in robotics, using serial chains of revolute and prismatic joints to approximate the motion of complex joints, is presented for use in LEMs. Important considerations such as linkage configuration and mechanism prototyping are also discussed. Another challenge in designing LEMs is creating multi-stable mechanisms with the ability to have coplanar links. A method is presented for offsetting the joint axes of a spatial compliant mechanism to introduce multi-stability. A new bistable spatial compliant linkage that uses that technique is introduced. In the interest of facilitating LEM design, the final chapter of this thesis presents a preliminary design method. While similar to traditional methods, this method includes considerations for translating the mechanism topology into a suitable configuration for use with planar layers of material.
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