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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the 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.
101

Designing the Human-Powered Helicopter: A New Perspective

Gradwell, Gregory Hamilton 01 June 2011 (has links)
The concept of human-powered vertical flight was studied in great depth. Through the manipulation of preexisting theory and analytical methods, a collection of design tools was created to expediently conceptualize and then analyze virtually any rotor. The tools were then arranged as part of a complete helicopter rotor design process. The lessons learned as a result of studying this process—and the tools of which it consists—are presented in the following discussion. It is the belief of the author that by utilizing these tools, as well as the suggestions that accompany them, future engineers may someday build a human-powered helicopter capable of winning the Sikorsky Prize.
102

Návrh rámu HPV / HPV

Šmak, Petr January 2008 (has links)
Design of frame of a human powered vehicle (HPV) is the aim of this diploma thesis. Wide analysis precedes design process. The thesis describes historical developement of land transportation, especially history of cycling, bicycles and other human povered vehicles, which are not so extended. Preferences and deficiencies of transportation by these ecological vehicles are shown. The thesis includes summary of most widespread and best-known conceptions, including their advantages and disadvanteges. Conception of three-wheeled vehicle was selected. It has two steered front wheels and one powered rear wheel. The accent is putted on wide efficiency, ergonomics, simplicity of vehicle`s frame and possibility of using common cycling components. 3D model of frame and assembly of vehicle was created. This model was checked by FEM computation.
103

Výpočet stability a řiditelnosti motorového kluzáku L-13 SE Vivat / Calculation of stability and control of the L-13 SE Vivat motor glider

Freisleben, Jan January 2010 (has links)
This diploma thesis deals with the calculation of stability and control of the L-13 SE Vivat Powered Glider. Furthermore comparing different methods of determining the aerodynamic derivatives.
104

Návrh pohonu elektrické tříkolky / Design of drive for electric powered tricycle

Filipec, Petr January 2011 (has links)
This work deals with designs of drive for two types electric powered tricycles (type for outdoor and indoor). Designs comprise general conception of drive. We selected optimal electric motors in terms of research electric engines and calculations. Next, we proposed batteries. The last part describes design power circuit and general financial expenses.
105

A Data Acquisition System Experiment for Gas Temperature and Pressure Measurements on a Liquid-Nitrogen-Powered Vehicle

Lui, Samson Sze-Sang 05 1900 (has links)
A data acquisition system was set up to measure gas temperatures and pressures at various points on a liquid-nitrogen-powered vehicle. The experiment was attempted to develop a data acquisition method for applications on engines that use liquid air as the fuel. Two thermocouples and a pressure transducer were connected using data acquisition instruments interfaced to a laptop computer to acquire data.
106

Wireless Powered Communication over Inductively Coupled Circuits

Tomohiro Arakawa (10716051) 06 May 2021 (has links)
Wireless powered communication (WPC) is an emerging paradigm where wireless devices are powered over the air while exchanging information with them. This technology is attractive for various wireless applications, including classical radio-frequency identification (RFID) systems, implantable sensors, environmental sensing as found in agriculture and forestry, and simultaneous charging and telemetry communications for electric vehicles. While recent studies have shown that inductive coupling provides a more energy-efficient and robust channel for short and middle-range wireless transmission, most of the previous analyses on WPC have been limited to far-field transmission models. To this end, this work provides a comprehensive framework to design and analyze WPC over inductively coupled circuits. We consider three problems, namely, wireless power transfer (WPT), simultaneous wireless information and power transfer (SWIPT), and wireless powered communication network (WPCN) using multiple coupled coils. Each configuration is modeled by an abstract circuit model in which various effects, including mutual coupling and parasitic elements, are captured by a small number of measurable parameters. This technique allows us to not only eliminate the need for solving the circuit but also apply well-known signal processing techniques such as beamforming and channel estimation to inductively coupled models. For each of the three models, we derive the properties of the optimal source signal. In addition, we propose methods to design the load impedance of WPCN by taking into account the nonlinear effects due to impedance mismatches in the circuits.
107

Grasped Object Detection for Adaptive Control of a Prosthetic Hand

Andrecioli, Ricardo 06 June 2013 (has links)
No description available.
108

An in-depth understanding of powered micro-mobility safety issues

Kazemzadeh, Khashayar, Sprei, Frances 03 January 2023 (has links)
The fast-growing market of powered micro-mobility, including electric bikes (e-bikes) and electric scooters (e-scooters), has introduced a paradigm shift in mobility across the world. These emerging transport modes have frequently been referred to as convenient mobility, having playfulness and transport functions. However, one of the main obstacles to the safe adoption of these transport modes is the safety issues related to their use. Based on the cycling literature, the interaction of vulnerable road users with each other could be classified based on the encounter directions. More specifically, passing is referred to as same-direction encounters, and meeting demonstrates opposite-direction encounters. Experiments and observations have been applied in this research domain for data collection, while interview setups are less conducted to explore users' opinions about their interactions. In this study, we conducted a series of semi-structured interviews and scrutinised e-bike and e-scooter users' safety issues in motorised and non-motorised facilities (e.g. shoulder lanes and sidewalks). [from Introduction]
109

Exploring the Concept of a Deep Space Solar-Powered Small Spacecraft

Crowley, Kian Guillaume 01 June 2018 (has links) (PDF)
New Horizons, Voyager 1 & 2, and Pioneer 10 & 11 are the only spacecraft to ever venture past Pluto and provide information about space at those large distances. These spacecraft were very expensive and primarily designed to study planets during gravitational assist maneuvers. They were not designed to explore space past Pluto and their study of this environment is at best a secondary mission. These spacecraft rely on radioisotope thermoelectric generators (RTGs) to provide power, an expensive yet necessary approach to generating sufficient power. With Cubesats graduating to interplanetary capabilities, such as the Mars-bound MarCO spacecraft, matching the modest payload requirements to study the outer Solar System (OSS) with the capabilities of low-power nano-satellites may enable much more affordable access to deep space. This paper explores a design concept for a low-cost, small spacecraft, designed to study the OSS and satisfy mission requirements with solar power. The general spacecraft design incorporates a parabolic reflector that acts as both a solar concentrator and a high gain antenna. This paper explores a working design concept for a small spacecraft to operate up to 100 astronomical units (AU) from the sun. Deployable reflector designs, thermal and radiation environments, communications and power requirements, solar system escape trajectory options, and scientific payload requirements are detailed, and a working system is proposed that can fulfill mission requirements with expected near-future innovations in a few key technologies.
110

Feasibility of Manipulating Correlated Color Temperatures with a Phosphor Converted High-Powered Light Emitting Diode White Light Source

Little, Matthew Michael 01 June 2010 (has links) (PDF)
In this thesis we examine the feasibility of developing a white light source capable of producing colors between 2500 and 7500 Kelvin on the black-body radiator spectrum by simply adjusting amperage to a blue and ultraviolet (UV) light emitting diode (LED). The purpose of a lighting source of this nature is to better replicate daylight inside a building at a given time of day. This study analyzes the proposed light source using a 385 nm UV LED, a 457 nm blue LED, a 479 nm blue LED, a 562 nm peak cerium doped yttrium aluminum garnet (YAG:Ce) phosphor, and a 647 nm peak selenium doped zinc sulfide (ZnS:Se) phosphor. Our approach to this study initially examined optical performance of yellow-emitting phosphor (YAG:Ce) positioned at specific distances above a blue LED using polydimethylsiloxane (PDMS) as a substrate. An understanding of how phosphor concentration within the PDMS, the thickness of the PDMS, and how substrate distance from the LED die affected light intensity and color values (determined quantitatively by utilizing the 1931 CIE 2° Standard Observer) enabled equations to be developed for various lens designs to efficiently produce white light using a 457 nm peak wavelength LED. The combination of two luminescent sources (457 nm LED and YAG:Ce) provided a linear trend on the 1931 CIE diagram which required a red illumination source to obtain Kelvin values from 2500 to 7500. Red-emitting phosphor (ZnS:Se), selected to compliment the system, was dispersed with YAG:Ce throughout PDMS where they were stimulated with a blue LED thereby enabling all desired Kelvin values with differing concentration lenses. Stimulating ZnS:Se with the addition of a UV LED did not provide the ability to change the color value of the set up to the degree required. Many other factors resulted in the decision to remove the UV LED contribution from the multi-Kelvin light source design. The final design incorporated a combination of ZnS:Se and YAG:Ce stimulated with a blue LED to obtain a 2500 Kelvin value. A separate blue LED provides the means to obtain 7500 Kelvin light and the other color values in between, with a linear approximation, by adjusting the amperages of both LEDs. In addition to investigating the feasibility of obtaining the Kelvin values from 2500 to 7500, this thesis also examined the problem of ZnS:Se’s inability to cure in PDMS and a method to create a lens shape to provide equal color values at all points above a phosphor converted LED source. ZnS:Se was found to be curable in PDMS if first coated with a low viscosity silicon oil prior to dispersion within PDMS. The lens configuration consists of phosphors equally distributed in PDMS and cured in the shape of a Gaussian distribution unique to multiple factors in LED-based white light design.

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