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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.
21

Design with Nature: Learning from Ecological Systems to Educate the Urban Dweller

Blackman, Clayton 19 March 2013 (has links)
Nature has an effective approach to cycling materials and energy flows to promote life. This thesis aims to expose urbanite users to nature’s way of cycling materials. The seawall is the largest public space in Vancouver at the edge of land and sea. A neighbourhood community centre along the edge called the Conservatory for Community Matters is created to nurture environmental stewardship by mimicking natural cycles in its function. By conveying architectural systems and form in a cyclical and organic approach, an architectural intervention can address the daily environmental impact of urbanites while rooting people in place and nature in the city. The community centre’s program connects the individually focused daily rituals of eating, making, and exercising to benefit the larger community where urbanites can reintegrate their organic ‘wastes’ into usable by-products. This promotes a paradigm shift transforming the apathetic consumer into an active member of the urban ecosystem.
22

AN APPROACH FOR DESIGN AND MANAGEMENT OF A SOLAR-POWERED CENTER PIVOT IRRIGATION SYSTEM

2013 November 1900 (has links)
Emerging financial and environmental challenges associated with conventional power sources have increased global interest in consuming unpolluted, renewable energy sources for irrigation sector. Solar energy may be an attractive choice in this regard due to its strong influence on crop water use and related energy requirement. However, a comprehensive approach for a reliable and economically viable photovoltaic (PV) system design to produce energy from solar source is required to accurately explore its potential. This thesis describes the development and application of a reliability assessment model, identifies a suitable solar irrigation management scheme, and provides guidelines for evaluating economic viability of a solar-powered center pivot irrigation system. The reliability model, written in MATLAB, was developed based on the loss of power supply probability (LPSP) technique in which various sub-models for estimating energy production, energy requirement and energy storage were combined. The model was validated with actual data acquired from the study site located at Outlook, Saskatchewan, Canada and an excellent agreement was found. For example, normalized root mean square error (NRMSE) for the battery current was found to be 0.027. Irrigation management strategies (irrigation depth, frequency and timing) were investigated by comparing the PV system sizing requirement for a conventional (25-35 mm per application) and for a frequent light irrigation management strategy (5-8 mm per application). The results suggest that the PV sizing can be reduced significantly by adopting frequent light irrigations which utilize the power as it is produced during daylight hours, rather than relying on stored energy. The potential of a solar-powered center pivot irrigation system was revealed for three different crops (canola, soybean and table potato) at the site by conducting a detailed economic analysis for the designed PV system. High value crops with moderate water requirements such as table potatoes appeared to be the most feasible choice for the study site. However, the potential may greatly vary for different crops in altered locations due to management, agronomic, climate, social, and economic variations. It can be concluded that a holistic approach described here can be used as a tool for designing an appropriate PV powered center pivot irrigation system under variable operating and meteorological conditions. Furthermore, its potential can be accurately explored by conducting a detailed economic analysis for a given location, considering different available crop choices.
23

Determinacao da sensibilidade de detetores auto-energizados (SPDs)

SURKOV, VADIM 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:37:58Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:05:51Z (GMT). No. of bitstreams: 1 05583.pdf: 4252573 bytes, checksum: 3380fa63516b077b4e7dbed167c467f8 (MD5) / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
24

Determinacao da sensibilidade de detetores auto-energizados (SPDs)

SURKOV, VADIM 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:37:58Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:05:51Z (GMT). No. of bitstreams: 1 05583.pdf: 4252573 bytes, checksum: 3380fa63516b077b4e7dbed167c467f8 (MD5) / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
25

Optimisation of electric long endurance unmanned aerial vehicles

Fourie, Dehann 06 June 2012 (has links)
M.Ing. / Sustained or long endurance solar powered flight is defined as an aircraft capable of main- taining flight through multiple day-night flight cycles, using only solar power and rechargable energy stores. The project is focused on developing solar powered flight theory and real-world unmanned aerial vehicle implementations. The important aspects of system design are es- tablished and studied at a fundamental theoretical level. A preliminary design is conducted with endurance optimisation as the main aim. The optimisation process aims to establish a theoretical basis for sustained solar powered flight. The project is started with a feasibility and relevance study. A literature study was used to gather the required theoretical information. A novel theoretical preliminary design basis is conducted. The study is aimed at answering many questions in the field. The study is the first to show how previously varied aircraft from 3 m to 80 m are valid solutions to the long endurance flight requirement. The optimisation results correlates well with the current state-of-the-art. The theoretical models were then characterised through the development of two unmanned aerial vehicles. The development required a multidisciplinary integration of various fields. The development process was characterised and discussed. Flight automation was successfully integrated into the system. Multiple test flights were conducted. An interpretation of multi- faceted results are given. This project has contributed to international theory regarding solar powered and sustained endurance aircraft. Many specific contributions were made to the field. The project has achieved multiple unofficial records from the flight tests in the Southern Hemisphere and African continent.
26

Konstrukční návrh hydraulického systému robotického exoskeletonu / Design of a hydraulic pressure system of a powered exoskeleton

Tomeček, Michal January 2021 (has links)
The main goal of this diploma thesis is to design a hydraulic system for robotic exoskeleton actuation. In the first part of the thesis a list of available sources of exoskeleton designs, is presented, followed by a thorough systematic analysis of hydraulic system elements and their use for this application, is made. The second part of the thesis consists of the hydraulic system design, as well the mechanical design for the hydraulic system which is subsequently tested structurally in the Autodesk Inventor software. The last part of the thesis consists of risk analysis and critical evaluation of thesis‘ results.
27

Energy Aware Routing Schemes in Solar PoweredWireless Sensor Networks

Dehwah, Ahmad H. 10 1900 (has links)
Wireless sensor networks enable inexpensive distributed monitoring systems that are the backbone of smart cities. In this dissertation, we are interested in wireless sensor networks for traffic monitoring and an emergency flood detection to improve the safety of future cities. To achieve real-time traffic monitoring and emergency flood detection, the system has to be continually operational. Accordingly, an energy source is needed to ensure energy availability at all times. The sun provides for the most inexpensive source of energy, and therefore the energy is provided here by a solar panel working in conjunction with a rechargeable battery. Unlike batteries, solar energy fluctuates spatially and temporally due to the panel orientation, seasonal variation and node location, particularly in cities where buildings cast shadows. Especially, it becomes scarce whenever floods are likely to occur, as the weather tends to be cloudy at such times when the emergency detection system is most needed. These considerations lead to the need for the optimization of the energy of the sensor network, to maximize its sensing performance. In this dissertation, we address the challenges associated with long term outdoor deployments along with providing some solutions to overcome part of these challenges. We then introduce the energy optimization problem, as a distributed greedy approach. Motivated by the flood sensing application, our objective is to maximize the energy margin in the solar powered network at the onset of the high rain event, to maximize the network lifetime. The decentralized scheme will achieve this by optimizing the energy over a time horizon T, taking into account the available and predicted energy over the entire routing path. Having a good energy forecasting scheme can significantly enhance the energy optimization in WSN. Thus, this dissertation proposes a new energy forecasting scheme that is compatible with the platform’s capabilities. This proposed prediction scheme was tested on real data and compared with state-of-theart forecasting schemes on on-node WSN platforms. Finally, to establish the relevance of the aforementioned schemes beyond theoretical formulations and simulations, all proposed protocols and schemes are subjected to hardware implementation.
28

Application of Pre-coated Microfiltration Ceramic Membrane with Powdered Activated Carbon for Natural Organic Matter Removal from Secondary Wastewater Effluent

Kurniasari, Novita 12 1900 (has links)
Ceramic membranes offer more advantageous performances than conventional polymeric membranes. However, membrane fouling caused by Natural Organic Matters (NOM) contained in the feed water is still become a major problem for operational efficiency. A new method of ceramic membrane pre-coating with Powdered Activated Carbon (PAC), which allows extremely contact time for adsorbing aquatic contaminants, has been studied as a pre-treatment prior to ceramic microfiltration membrane. This bench scale study evaluated five different types of PAC (SA Super, G 60, KCU 6, KCU 8 and KCU 12,). The results showed that KCU 6 with larger pore size was performed better compared to other PAC when pre-coated on membrane surface. PAC pre-coating on the ceramic membrane with KCU 6 was significantly enhance NOM removal, reduced membrane fouling and improved membrane performance. Increase of total membrane resistance was suppressed to 96%. The removal of NOM components up to 92%, 58% and 56% for biopolymers, humic substances and building blocks, respectively was achieved at pre-coating dose of 30 mg/l. Adsorption was found to be the major removal mechanism of NOM. Results obtained showed that biopolymers removal are potentially correlated with enhanced membrane performance.
29

Design and Prototype Validation of a Laterally Mounted Powered Hip Joint for Hip Disarticulation Prostheses

Mroz, Sarah 26 May 2023 (has links)
Powered prostheses are at the forefront of prosthetic technology, improving functionality by providing positive power to joints in the absence of native anatomy. Currently, there is no commercially available powered solution for hip-level amputees, and most hip prostheses are mounted to the front of the prosthetic socket. This thesis designed, fabricated, and tested a novel Laterally Mounted Powered Hip Joint (LMPHJ) that augments user gait to promote improved walking patterns. The LMPHJ attaches to the lateral side of the prosthetic socket, locating the hip centre of rotation closer to the anatomical location while ensuring user safety and stability. The new design locates the motor and all electronics in the thigh area, thereby maintaining a low profile while transmitting the required hip moments to the joint centre of rotation. A prototype was designed and manufactured to evaluate LMPHJ performance. Mechanical testing followed the ISO 15032:2000 standard and successfully demonstrated the joint's resistance to everyday loading conditions. Functional testing involved integrating the LMPHJ, Ossur Rheo Knee, and Ossur Pro-Flex XC with a prosthesis simulator that allowed three able-bodied participants to walk with the powered prosthesis successfully. This validated the mechanical design for walking over level ground and demonstrated that the LMPHJ is ready for next phase evaluation with hip disarticulation amputee participants.
30

Resource Management in Solar Powered Wireless Mesh Networks

Badawy, Ghada 01 1900 (has links)
<p> Wireless mesh networks are now being used to deploy radio coverage in a large variety of outdoor applications. One of the major obstacles that these networks face is that of providing the nodes with electrical power and wired network connections. Solar powered mesh nodes are increasingly used to eliminate the need for these types of connections, making the nodes truly tether-less. In these types of networks however, the cost of the energy collection and storage components can be a significant fraction of the total node cost, which motivates a careful selection of these resources.</p> <p> This thesis focusses on key issues relating to the deployment and operation of solar powered wireless mesh networks. First, the problem of provisioning the mesh nodes with a suitable solar panel and battery configuration is considered. This is done by assuming a bandwidth usage profile and using historical solar insolation data for the desired deployment location. A resource provisioning algorithm is proposed based on the use of temporal shortest-path routing and taking into account the node energy-flow for the target deployment time period. A methodology is introduced which uses a genetic algorithm (GA) to incorporate energy-aware routing into the resource assignment procedure. Results show that the proposed resource provisioning algorithm can achieve large cost savings when compared to conventional provisioning methods.</p> <p> During post-deployment network operation, the actual bandwidth profile and solar insolation may be different than that for which the nodes were originally provisioned. To prevent node outage, the network must reduce its workload by flow controlling its input traffic. The problem of admitting network bandwidth flows in a fair manner is also studied. A bound is first formulated which achieves the best max/min fair flow control subject to eliminating node outage. The bound motivates a proposed causal flow control algorithm whose operation uses prediction based on access to on-line historical weather data. The results show that the proposed algorithm performs well when compared to the analytic bound that is derived for this problem.</p> <p> Finally, as user traffic evolves, the network resources need to be updated. This problem is considered using a minimum cost upgrade objective. A mixed integer linear programming (MILP) formulation is derived to obtain a lower bound on the network update cost. A genetic algorithm is used to determine practical cost-effective network resource upgrading. The results show that the proposed methodology can obtain significant cost savings.</p> / Thesis / Doctor of Philosophy (PhD)

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