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.
Results
Showing 1 to 20 of 58 for “"Duty cycles"”.
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Development of naval diesel engine duty cycles for air exhaust emission environmental impact analysis
Thesis (Nav. E.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, 1994, and Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1994.
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Characterization of infield duty cycles and exhaust emissions from diesel powered off-road heavy-duty equipment
… was logged during in-field operation, and test cycles were created on a dynamometer test bed using this data. For the tractor, on-board emissions measurement equipment collected mass emissions rate data in field.;Vast differences were found between transient and 8-mode brake-specific test …
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CRSN Energy-Efficient Mechanism Based on Dynamic Spectrum Access and Asynchronous Sleep-Wake Scheduling
… asynchronous data transmission and sleep-wake cycles to control the flow of data and reduce interferences in the network. To evaluate the performance and effectiveness of the solution, simulations were conducted on six S-MAC's duty cycles of 3%, 5%, 10%, 15%, 25%, and 50% and assessed using …
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Optical communications with a Geiger mode APD array
… PPM modulations at a variety of symbol rates and duty cycles. Using this pattern generator, I tested the receiver properties over a wide range of data rates and illumination levels, and was able to demonstrate the capability for error-free communications in both modulation formats, up to 78.8 Mbps …
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Spray characteristics of throttle body fuel injection
… steady operation and over a range of injector duty cycles common in engine operation. In subsequent experiments, spray characteristics were measured at the throttle body exit under simulated engine conditions. The study also included correlation of experimental spray results with performance …
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A software package for estimation of weights & volumes of spaceborne power systems
… may be specified are power requirement, orbit, duty cycles, etc. A complete User's Manual which describes the working methods to create new databases and enter new data, and includes error handling techniques has been generated. The result is an interactive, menu driven, user friendly software …
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Stability of Field Emitter Arrays to Oxygen Exposures
… a leak valve for different lengths of time and duty cycles. To ensure identical oxygen exposure and experimental measurement conditions, tips on half the area of the FEA were fully coated with gold and the other half were left uncoated. The emission current from the gold coated half was found to …
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Exploring subjective and objective localized muscle fatigue responses at recommended upper limb ergonomics limits
… for a given level of repetitive work (i.e. duty cycle). Exposures at higher duty cycles (and lower force intensity) were found to elicit the largest LMF responses. This thesis concludes with practical recommendations to help ergonomists better assess and prevent the accumulation of excessive …
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ASSESSING THE IMPACT OF TACTICAL MISSION PROFILES ON THE DEVELOPMENT OF POWER PREDICTION SOFTWARE
… profiles and mission blocks to define candidate duty cycles and assess the impact that alterations to those mission profiles have on power usage.
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An Evaluation of Fatigue and Performance Changes During Intermittent Overhead Work
… in eight experimental conditions (two levels of duty cycles, two work heights, and two hand positions). Four dependent measures based on endurance, subjective, objective, and physiological fatigue were used to quantify shoulder fatigue and were collected during the experiment. An overhead work …
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Electrostatic Micro Gas Pumping for Micro Gas Chromatography Systems---Fabrication and Experiments
… with various actuation voltages and various duty cycles, and corresponding stroke volume and flow rates are measured.
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Design of sparse signaling schemes in fading wideband channels
… keying, which is frequency shift keying with a duty cycle, is one such signaling scheme that has been shown to perform better than code division multiple access and orthogonal frequency di-vision multiplexing in the wideband regime without channel state information, but lacks practicality due to …
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Rotary-linear axes for high speed machining
… accelerations of 12 g's and 17,500 rad/s2 at low duty cycles. This thesis also examines several concepts for developing a precision rotary-linear sensor that can tolerate axial translation.
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Quantifying Localized Muscle Fatigue of the Forearm during Simulations of High Pressure Cleaning Lance Tasks
… to the operator and parallel to the ground), and duty cycle (33, 50, and 67%) based on task analyses of actual work tasks. Dependent variables included mean RMS and rates of change in mean RMS, mean and median power frequency, MVE, and subjective ratings of fatigue. Repeated measures ANOVA was …
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Modelling and Evaluation of Piezoelectric Actuators for Wearable Neck Rehabilitation Devices
… velocity of the hybrid model at different duty cycles was compared to the real TWUM being modelled, producing a coefficient of determination of 0.974. The model was then used to create a position control system that controlled the joints of a virtual robotic manipulator that modelled the …
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Communications over fading channels with partial channel information : performance and design criteria
… (i.i.d.) Gaussian signals. A simple, low-duty-cycle signaling scheme is proposed to improve the information rates for low signal-to-noise ratio (SNR), and the optimal duty cycle is expressed as a function of the fading rate and SNR. It is demonstrated that the resource allocations and duty …
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A Self-Retracting Fully-Compliant Bistable Micromechanism
… device, subjecting it to approximately 2 million duty cycles without failure. Based on the SRFBM concept a number of improvements and adaptations are presented, including systems with further power and displacement reductions and a G-switch for LIGA fabrication.</p>
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Circuits and protocols for low duty cycle wireless systems
… efficiency is needed. Additionally, aggressive duty cycling is needed to operate these IoT devices in severely energy-constrained applications. Wireless communication, which consumes a large fraction of the power in these devices, is the primary focus of this thesis. We present circuit (active …
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The effect of overloading on reliability of wheel loader structural components
… on data samples to test the hypotheses. Duty-cycle relationships were established using linear life stress relationships ratios for the wheel loaders structural components. The research showed that, while higher bucket loads increase productivity, there is evidence that they slow down the …
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Numerical Simulation of Vortex Generating Jets in Zero and Adverse Pressure Gradients
… to assume that reduced blowing ratios and duty cycles would produce similar shear layer vortices and comparable loss reductions. Influences of both turbulent transition and dominant vortical structures were observed, though the spanwise shear layer vortices appear to be critical to the …
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