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- Teleoperation (2)
- Amorphous selenium (1)
- Communication unreliability (1)
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- Face-gear (1)
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- Finite elements (1)
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- High temperature gas reactor (1)
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- Hybrid adaptive control (1)
- Imbalance vibration (1)
- Instrumented indentation (1)
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- Parametric instability (1)
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- Periodically time-varying system (1)
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Articles 1 - 6 of 6
Full-Text Articles in Mechanical Engineering
Steam Reheat In Nuclear Power Plants, Paul John Marotta
Steam Reheat In Nuclear Power Plants, Paul John Marotta
Doctoral Dissertations
In this work, reheating steam from a commercial nuclear power plant is explored in order to increase efficiency and power output. A thermal source in the form of a High Temperature Gas Reactor (HTGR) is considered. Engineering challenges include proof-of-principle, reactor sizing, evaluation, and feasibility.
The proposed thermodynamic process modifications have been evaluated for a range of inlet steam quality conditions. The evaluation of the steam tube dimensions and number of optimal tubes have been calculated utilizing the so-called Log Mean Temperature Difference method. Subsequently, the performance of the steam tubes was further analyzed within a water vapor and liquid …
Passive Control Architectures For Collaborative Virtual Haptic Interaction And Bilateral Teleoperation Over Unreliable Packet-Switched Digital Network, Ke Huang
Doctoral Dissertations
This PhD dissertation consists of two major parts: collaborative haptic interaction (CHI) and bilateral teleoperation over the Internet. For the CHI, we propose a novel hybrid peer-to-peer (P2P) architecture including the shared virtual environment (SVE) simulation, coupling between the haptic device and VE, and P2P synchronization control among all VE copies. This framework guarantees the interaction stability for all users with general unreliable packet-switched communication network which is the most challenging problem for CHI control framework design. This is achieved by enforcing our novel \emph{passivity condition} which fully considers time-varying non-uniform communication delays, random packet loss/swapping/duplication for each communication channel. …
Parametric Instability Investigation And Stability Based Design For Transmission Systems Containing Face-Gear Drives, Meng Peng
Doctoral Dissertations
The objective of this dissertation is to provide a novel design methodology for face-gear transmissions based on system stability - a dynamics viewpoint. The structural dynamics models of transverse and torsional vibrations are developed for face-gear drives with spur pinions to investigate the parametric instability behavior in great depth. The unique face-gear meshing kinematics and the fluctuation of mesh stiffness due to a nonunity contact-ratio are considered in these models. Since the system is periodically timevarying, Floquet theory is utilized to solve the Mathieu-Hill system equations and determine the system stability numerically. To avoid complex numerical computations, Treglod’s approximation is …
Measurement Of Power-Law Creep Parameters By Instrumented Indentation Methods, Caijun Su
Measurement Of Power-Law Creep Parameters By Instrumented Indentation Methods, Caijun Su
Doctoral Dissertations
New experimental methods have been developed to measure the uniaxial power-law creep parameters α [alpha] and n in the relation έ[epsilon dot]=α[alpha]σn[sigma] (έ [epsilon dot] is the creep strain rate and σ [sigma] is the creep stress) from the load, time, displacement and stiffness data recorded during an instrumented indentation experiment performed with a conical or pyramidal indenter. The methods are based on an analysis of Bower et al., which relates the indentation creep rate to the uniaxial creep parameters based on simple assumptions about the constitutive behavior (Bower et al., 1993 …
Nonlinear Vibration Control And Limit-Cycle Analysis Of Rotor/Autobalancer Systems Equipped With Hydrodynamic And Active Magnetic Bearing Supports, Daeyi Jung
Doctoral Dissertations
In recent years, there has been much interest in the use of automatic balancing devices (ABDs) in rotating machinery. Autobalancers consists of several freely moving eccentric balancing masses mounted on the rotor, which, at certain operating speeds, act to cancel rotor imbalance. This “automatic balancing” phenomena occurs as a result of nonlinear dynamic interactions between the balancer and rotor wherein the balancer masses naturally synchronize with the rotor with appropriate phase to cancel the imbalance. However, due to inherent nonlinearity of the autobalancer, the potential for other undesirable non-synchronous limit-cycle behavior exists. In such situations, the balancer masses do not …
Vision-Based Robot Control In The Context Of Human-Machine Interactions, Andrzej Nycz
Vision-Based Robot Control In The Context Of Human-Machine Interactions, Andrzej Nycz
Doctoral Dissertations
This research has explored motion control based on visual servoing – in the context of complex human-machine interactions and operations in realistic environments. Two classes of intelligent robotic systems were studied in this context: operator assistance with a high dexterity telerobotic manipulator performing remote tooling-centric tasks, and a bio-robot for X-ray imaging of lower extremity human skeletal joints during natural walking. The combination of human-machine interactions and practical application scenarios has led to the following fundamental contributions: 1) exploration and evaluation of a new concept of acquiring fluoroscope images of musculoskeletal features of interest during natural human motion, 2) creation …