Dissertations / Theses on the topic 'Harvesters'
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Sun, Huihui. "Miniature wind energy harvesters." Thesis, University of Southampton, 2017. https://eprints.soton.ac.uk/416874/.
Full textSimeone, Luigi. "Nonlinear damping in energy harvesters." Thesis, University of Southampton, 2017. https://eprints.soton.ac.uk/426890/.
Full textHogue, Daniel B., and Sarah M. Gregory. "MEMS-based waste vibrational energy harvesters." Monterey, California: Naval Postgraduate School, 2013. http://hdl.handle.net/10945/34678.
Full textThe piezoelectric effect is a phenomenon where strain on a piezoelectric crystal structure causes potential difference at its ends. By merging piezoelectric materials and microelectromechanical systems (MEMS), mechanical vibration could cause the necessary displacement in MEMS to create a potential difference that could be used to power electronic devices. Developing new sustainable energy sources and using energy more efficiently is at the forefront of several research initiatives and is a clear priority for the Department of the Navys strategic planning. This thesis aims to design a vibrational energy harvesting MEMS device to harness vibrational waste energy with the goal of producing power for naval applications. The development and widespread use of vibrational harvesting MEMS would aid the effort to meet each of these goals in the Department of the Navy. Any shore based, seagoing, or expeditionary mechanical platform could serve as a kinetic energy source for vibration energy harvesting MEMS. This thesis investigates the physics, materials, design, optimization, and microfabrication process in the creation of such a device. Time-dependent finite element models for two designs have been developed, simulating electrical power output. Microfabrication processes for the designs have also been developed.
Jalali, Nimra. "ZnO nanorods-based piezoelectric energy harvesters." Thesis, Queen Mary, University of London, 2015. http://qmro.qmul.ac.uk/xmlui/handle/123456789/8948.
Full textLechuga, Aranda Jesus Javier. "Interfaces In Hydraulic Pressure Energy Harvesters." Licentiate thesis, Mittuniversitetet, Institutionen för elektronikkonstruktion, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-36106.
Full textDen fjärde industriella revolutionen är här vilket innebär en rad utmaningar för att dess utveckling ska bli framgångsrik. En av de största utmaningarna som begränsar utvecklingen av sakernas internet för industriella tillämpningar är strömförsörjningen av trådlösa sensorer då dessa är beroende av batterier med begränsad livslängd. Nya framsteg har emellertid gjorts med tekniker för energiskördning som gör att livslängden för batterierna kan förlängas ochi förlängningen helt ersätta batterierna. Det, i sin tur, möjliggör autonoma sensorer som är självförsörjande på energi som är viktiga komponenter i sakernas internet. Energiskördning är den process som omvandlar energi som finns i omgivningen till elektrisk energi. För att kunna få ut så mycket energi som möjligt så är det avgörande att energiskördarna gör energiomvandlingen så effektivt som möjligt. Det gör att inhämtning av omgivande energi samt gränssnitt och energiomvandling måste förstås och karakteriseras för varje tillämpning. Den här avhandlingen undersöker energiskördning för hydrauliskasystem där tryckfluktuationer i dessa system är energikällan. Syftet med den här studien är att ta fram metoder för uppskattning och karakterisering av de nödvändiga gränssnitten för inhämtning, fokusering, och omvandling av fluktuationer i hydraultryck till elektrisk energi. Sammanfattningsvis visar avhandlingen att metoder för att omvandla tryckfluktuationer i hydraulsystem till elektrisk energi beror på den hydrauliska systemmiljön där det statiska trycket och frekvensen av tryckfluktuationerna är de viktigaste parametrarna. Resultaten kan fungera som utgångspunkt för fortsatt forskning och utveckling av energiskördare för hydrauliska system.
SMART (Smarta system och tjänster för ett effektivt och innovativt samhälle)
Erturk, Alper. "Electromechanical Modeling of Piezoelectric Energy Harvesters." Diss., Virginia Tech, 2009. http://hdl.handle.net/10919/29927.
Full textPh. D.
Hehn, Thorsten [Verfasser], and Yiannos [Akademischer Betreuer] Manoli. "A CMOS Integrated Interface Circuit for Piezoelectric Energy Harvesters = Eine CMOS-Integrierte Schnittstellenschaltung für Piezoelektrische Energy Harvester." Freiburg : Universität, 2014. http://d-nb.info/1123479119/34.
Full textTran, Thang Quang. "DYNAMIC RESPONSE OF AND POWER HARVESTED BY ROTATING PIEZOELECTRIC VIBRATION ENERGY HARVESTERS THAT EXPERIENCE GYROSCOPIC EFFECTS." OpenSIUC, 2017. https://opensiuc.lib.siu.edu/theses/2157.
Full textLi, Xuan. "Design and development of hybrid energy harvesters." Thesis, Queen Mary, University of London, 2018. http://qmro.qmul.ac.uk/xmlui/handle/123456789/42507.
Full textLi, Yuan. "Investigation into new non-linear energy harvesters." Thesis, University of Southampton, 2015. https://eprints.soton.ac.uk/388049/.
Full textThorner, Lauriane Daniele Amelie. "Miniaturized energy harvesters in a fluid environment." Thesis, Imperial College London, 2013. http://hdl.handle.net/10044/1/12864.
Full textElliott, Alwyn David Thomas. "Power electronic interfaces for piezoelectric energy harvesters." Thesis, Imperial College London, 2015. http://hdl.handle.net/10044/1/39965.
Full textKhan, Syed Farid Ullah. "Vibration-based electromagnetic energy harvesters for MEMS applications." Thesis, University of British Columbia, 2011. http://hdl.handle.net/2429/33833.
Full textMak, Kuok Hang. "Vibration modelling and analysis of piezoelectric energy harvesters." Thesis, University of Nottingham, 2011. http://eprints.nottingham.ac.uk/12534/.
Full textPedrosa, Steven Michael. "Study of high efficiency micro thermoelectric energy harvesters." Master's thesis, University of Central Florida, 2011. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/4820.
Full textID: 031001306; System requirements: World Wide Web browser and PDF reader.; Mode of access: World Wide Web.; Title from PDF title page (viewed March 18, 2013).; Thesis (M.S.M.E.)--University of Central Florida, 2011.; Includes bibliographical references (p. 88-89).
M.S.M.E.
Masters
Mechanical and Aerospace Engineering
Engineering and Computer Science
Mechanical Engineering; Miniature Engineering Systems Track
Householder, Timothy J. "MEMS-based waste vibration and acoustic energy harvesters." Thesis, Monterey, California: Naval Postgraduate School, 2014. http://hdl.handle.net/10945/44583.
Full textEvery machine vibrates and emits noise. This is unused energy that, with an appropriate mechanism, can be returned to the system. Utilizing an array of piezoelectric microelectromechanical systems (MEMS) devices to harvest this otherwise wasted energy, it is possible to improve the efficiency of any number of mechanical devices. Piezoelectricity is the mechanism by which certain crystalline structures generate electric potential when under strain, or, conversely, deform when subjected to an electric potential. It is this first effect that is important to this application. Though each MEMS device will generate a very small amount of power, a 1 m2 area can contain an array of millions of these devices. Energy harvesting, conservation, and efficiency are all key Department of Defense (DOD) priorities, and the universal application of these devices make them ideal for any expeditionary platform, such as ships, aircraft, and automobiles. This thesis designs and tests the first generations of acoustic and vibrational piezoelectric MEMS devices; including time-dependent finite element models, microfabrication processes, and the initial attempts at characterization and optimization.
Cox, Graeme J. "A yield mapping system for sugar cane chopper harvesters." University of Southern Queensland, Faculty of Engineering and Surveying, 2002. http://eprints.usq.edu.au/archive/00004617/.
Full textMcCarthy, Stuart George. "The integration of sensory control for sugar cane harvesters." University of Southern Queensland, Faculty of Engineering and Surveying, 2003. http://eprints.usq.edu.au/archive/00001469/.
Full textFrazier, Kyle W. "Safety and health perceptions and concerns of custom harvesters /." Available to subscribers only, 2006. http://proquest.umi.com/pqdweb?did=1136090901&sid=18&Fmt=2&clientId=1509&RQT=309&VName=PQD.
Full textPatel, Rupesh. "Modelling analysis and optimisation of cantilever piezoelectric energy harvesters." Thesis, University of Nottingham, 2013. http://eprints.nottingham.ac.uk/13246/.
Full textKluger, Jocelyn Maxine. "Nonlinear beam-based vibration energy harvesters and load cells." Thesis, Massachusetts Institute of Technology, 2014. http://hdl.handle.net/1721.1/87958.
Full textCataloged from PDF version of thesis.
Includes bibliographical references (pages 216-218).
This thesis studies a novel nonlinear spring mechanism that is comprised of a cantilever wrapping around a curved surface as it deflects. Static force versus displacement tests and dynamic "initial displacement" tests verified the spring theory for a large range of oscillator parameters. Various human motion energy harvester configurations that use the nonlinear spring were numerically optimized for power, robustness, and adaptivity. Based on the optimization results, both the nonlinear and linear devices studied in this thesis generate more power per volume and per mass when excited at one's hip while walking than current commercial energy harvesters. The two degree-of-freedom (2DOF) nonlinear oscillator is more adaptive to different excitation signals and resistant to power decay when parasitic damping is present than the IDOF and 2DOF linear systems. These significant advantages are caused by the 2DOF nonlinear system harvesting its optimal power at large electromagnetic damping coefficients, whereas the optimal power generation for the linear systems occurs at low electromagnetic damping coefficients. This thesis also examined what electromagnetic damping coefficients can be generated by magnet-and-coil geometries that satisfy the energy harvester constraints. The final chapter of this thesis investigates a load cell that uses the stiffening spring to maintain high resolution over a large range of forces and prevent large forces from damaging the load cell. Future work will include testing a full energy harvester prototype and exploring other applications of the nonlinear spring.
by Jocelyn Maxine Kluger.
S.M.
Yoon, You C. (You Chang). "Design of test bench apparatus for piezoelectric energy harvesters." Thesis, Massachusetts Institute of Technology, 2012. http://hdl.handle.net/1721.1/86267.
Full textCataloged from PDF version of thesis.
Includes bibliographical references (page 48).
This thesis presents the design and analysis of an experimental test bench for the characterization of piezoelectric microelectromechanical system (MEMS) energy harvester being developed by the Micro & Nano Systems Laboratory research group at MIT. Piezoelectric MEMS energy harvesters are micro-devices that are able to harvest energy from their ambient vibrations using piezoelectric material property, and many different designs are being researched by the Micro & Nano Systems Laboratory. In order to analyze the different designs, it is crucial to have a flexible test bench, and the test bench created in this thesis allows data to be gathered easily from different energy harvesters. After the test bench is designed and created, it is used to excite a linear cantilever beam energy harvester system at different frequencies and values for open circuit voltage, resonance frequency, and maximum power are calculated from the collected experimental data. In addition, theory behind linear and nonlinear energy harvester systems is investigated and important definitions, characteristics, and equations are summarized in this thesis.
by You C. Yoon.
S.B.
Joo, Han Kyul. "Single-degree-of-freedom energy harvesters by stochastic excitation." Thesis, Massachusetts Institute of Technology, 2014. http://hdl.handle.net/1721.1/92138.
Full textCataloged from PDF version of thesis.
Includes bibliographical references (pages 97-100).
In this thesis, the performance criteria for the objective comparison of different classes of single-degree-of-freedom oscillators under stochastic excitation are developed. For each family of oscillators, these objective criteria take into account the maximum possible energy harvested for a given response level, which is a quantity that is directly connected to the size of the harvesting configuration. We prove that the derived criteria are invariant with respect to magnitude or temporal rescaling of the input spectrum and they depend only on the relative distribution of energy across different harmonics of the excitation. We then compare three different classes of linear and nonlinear oscillators and using stochastic analysis tools we illustrate that in all cases of excitation spectra (monochromatic, broadband, white-noise) the optimal performance of all designs cannot exceed the performance of the linear design. Subsequently, we study the robustness of this optimal performance to small perturbations of the input spectrum and illustrate the advantages of nonlinear designs relative to linear ones.
by Han Kyul Joo.
S.M.
Good, Grant. "Feasibility of diesel-electric hybrid drives for combine harvesters." Thesis, Kansas State University, 2013. http://hdl.handle.net/2097/19754.
Full textDepartment of Agricultural Economics
Jason Bergtold
Efficiency and technology are increasingly important selling points for combine harvesters. Diesel-electric hybrid drives have taken hold in the construction equipment industry, and are providing marketable efficiency benefits for some heavy equipment customers. This thesis explores the technical and economic feasibility of utilizing diesel-electric hybrid drives on AGCO combine harvesters. To determine the technical feasibility of utilizing diesel-electric hybrid drives on AGCO combine harvesters, a search was conducted for prior literature relating to the use of electric drives on other heavy, off-highway equipment. This information, coupled with data provided by experts in the field, was used to determine if electric drives could fulfill the unique requirements of combine harvesters, and be practically utilized for this application. To determine the economic feasibility of utilizing diesel-electric hybrid drives on AGCO combine harvesters, an optimization model was constructed to seek out the most economically viable configuration of electric drives for this application. The model takes in to consideration the different use-cases in which this equipment is expected to perform, as well as the component costs and operating efficiencies of both the drives in place currently and the proposed electric drives. The outcome of the model was then utilized to compare the best-case configuration to the minimum requirement for economic feasibility. The technical feasibility assessment conducted for this thesis led to the conclusion that it would be technically feasible to utilize electric drives on a combine harvester. There are commercially available electric drive components which are suitable for use in the environment that this equipment is expected to operate in, and a prototype combine harvester having electric drives has previously been constructed. The economic feasibility assessment conducted for this thesis revealed that it is not economically feasible to utilize electric drives on AGCO combine harvesters at this time. Under the current circumstances, the most economically viable configuration would take nearly twice the machine’s usable operating life to provide a benefit to a customer from fuel savings. Sensitivity analysis revealed that significant changes in the price of fuel or electric drive components would be necessary to change the outcome of this study.
Crowe, Jennifer. "Heat exposure and health outcomes in Costa Rican sugarcane harvesters." Doctoral thesis, Umeå universitet, Epidemiologi och global hälsa, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-93609.
Full textLarson, Geremy. "Self-propelled forage harvester sales analysis." Thesis, Kansas State University, 2015. http://hdl.handle.net/2097/35746.
Full textDepartment of Agricultural Economics
Major Professor Not Listed
Self-propelled forage harvesters are used to make feed for livestock. Producers prefer forage made with these machines because they are able to deliver a feed value that enables improved productivity of their animals in terms of milk production for dairy animals and weight gain for beef animals. Self-propelled forage harvesters are able to make a variety of feed from different crops, including whole-plant corn silage, earlage, and haylage, among others. The self-propelled forage harvester is a complex and expensive piece of machinery for a producer to own. The self-propelled forage harvester market in the United States is a growing market, but small when compared to other equipment such as combines. In today’s environment, productivity is crucial to the success of the agricultural producer. Self-propelled forage harvesters are no exception. Growth of the self-propelled forage harvester market is reflected in increased unit sales, total horsepower sold, and average horsepower of the selfpropelled forage harvesters sold in the United States. This study looks at changes in the number and size of self-propelled forage harvesters being purchased and what factors might be driving those changes. This study found that the amount of milk produced, the type of customer purchasing the equipment, and the average price of milk a producer received explained 81.2% of the variation in the number of self-propelled forage harvesters sold from 2000- 2014. Study results also show that the size of dairy operation, the type of customer purchasing the equipment, and the average price of milk explained 88% of the variability in total horsepower of self-propelled forage harvesters sold from 2000-2014. Finally, the size of dairy operation that a typical cow comes from, the type of customer purchasing the equipment, and the average price of corn were able to explain 98% of the variation of average horsepower of self-propelled forage harvesters over that same time period. The model and analysis will be shared with product planners from John Deere as they develop new machine specifications for self-propelled forage harvesters in the future.
Goldenetz, Jolie A. "Learning from Traditional Water Harvesters in the Negev and Sonoran Deserts." Arizona-Nevada Academy of Science, 2006. http://hdl.handle.net/10150/296663.
Full textBowden, James Anthony. "Electrical tuning of electromagnetic energy harvesters with switched mode power electronics." Thesis, University of Bristol, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.616884.
Full textHendrix, Christopher (Christopher M. ). "Feasibility of passive electromagnetic dampers as energy harvesters in large structures." Thesis, Massachusetts Institute of Technology, 2013. http://hdl.handle.net/1721.1/82816.
Full textCataloged from PDF version of thesis.
Includes bibliographical references (p. 44).
There has been a trend in structural design toward energy efficient design and motion based design. The strategy of motion based design is controlling the movement of structures to meet certain dynamic response requirements by damping the structure. Structural damping dissipates the energy of external loads internally within the structure. A simple idea is to connect the two design strategies to control the motion of a structure while harvesting this dissipated energy by transducing it to electrical energy via passive electromagnetic damping. This study will attempt to determine the feasibility of using passive electromagnetic damping to control the motion and harvest the energy of damping of large scale structures.
by Christopher Hendrix.
M.Eng.
Kim, Miso. "Materials and device design for MEMS piezoelectric mechanical vibration energy harvesters." Thesis, Massachusetts Institute of Technology, 2012. http://hdl.handle.net/1721.1/101863.
Full textCataloged from PDF version of thesis.
Includes bibliographical references (pages 234-245).
Piezoelectric vibration energy harvesters (PVEHs) for microelectromechanical systems (MEMS) have received considerable attention as an enabling technology for self-powered wireless sensor networks. MEMS-PVEHs are particularly attractive because of the potential to deliver power indefinitely and their ability to be integrated concurrently with microfabrication of sensor nodes. A key challenge has been insufficient power and voltage generation for practical applications. Along with research efforts on improved materials, efficient electronics, and fabrication of devices, modeling is an indispensable element in predicting and designing PVEHs. Here, an improved electromechanically-coupled model is developed including the ability to analyze proof mass effects and different electrode configurations. Although essential in microscale devices to move device resonances towards optimal frequency points for harvesting, proof masses have not been treated rigorously in extant work. An improved treatment of a rigid proof mass with rotation, and an exact treatment (two-beam model) of a flexible proof mass, are presented and experimentally verified using a macroscale, symmetric, bimorph, cantilevered PVEH device operating in {3-1} mode with a rigid proof mass, and a micron-scale Si cantilever with a flexible proof mass, respectively. Focused ion beam milling is used to create different flexible proof masses, and atomic force microscopy is used to study the mechanical behavior of micron-scale, single-crystal Si cantilevers. It is found that the two-beam model is necessary for the majority of the proof mass cases considered, especially when considering key power-generation characteristics such as strain developed in the piezoelectric layers. The effects of piezoelectric material properties on device performance are studied via model-based sensitivity analyses to gain insight into the design and selection of optimal piezoelectric materials for power and voltage generation. Notably, and non-intuitively, optimum power either at resonance or antiresonance is independent of the piezoelectric coupling constant of the piezoelectric material, obviating the oft-cited rationale for materials research to increase piezoelectric coupling coefficients. For example, in an exemplary PVEH optimization, maximum power and voltage are obtained at relatively low values (30-40% of bulk PZT, near AlN and ZnO film values) of piezoelectric coupling coefficients. The improved model is used as a multi-variable design tool for designing a novel piezoelectric/ultrananocrystalline diamond (UNCD) heterostructure MEMS-PVEH device. This thesis contributes to the development of MEMS- PVEHs by offering new insights at both the materials and system levels, including optimization findings using different objective functions, such as efficiency. Future work includes application of the modelderived piezoelectric materials design guidelines to aid in the design of optimal MEMS-PVEH systems, fabrication of designed UNCD/piezoelectric-based MEMS-PVEHs, and analytical and experimental studies of both structural and piezoelectric fatigue phenomena for enhanced reliability of PVEHs.
by Miso Kim.
Ph. D.
Xu, Ruize Ph D. Massachusetts Institute of Technology. "The design of low-frequency, low-g piezoelectric micro energy harvesters." Thesis, Massachusetts Institute of Technology, 2012. http://hdl.handle.net/1721.1/74954.
Full textCataloged from PDF version of thesis.
Includes bibliographical references (p. 107-112).
A low-frequency, low-g piezoelectric MEMS energy harvester has been designed. Theoretically, this new generation energy harvester will generate electric power from ambient vibrations in the frequency range of 200~30OHz at excitation amplitude of 0.5g. Our previous energy harvester successfully resolved the gain-bandwidth dilemma and increased the bandwidth two orders of magnitude. By utilizing a doubly clamed beam resonator, the stretching strain triggered at large deflection stiffens the beam and transforms the dynamics to nonlinear regime, and increases the bandwidth. However, the high resonance frequency (1.3kHz) and the high-g acceleration requirement (4-5g) shown in the testing experiments limited the applications of this technology. To improve the performance of the current energy harvesters by lowering the operating frequency and excitation level, different designs have been generated and investigated. Moreover, a design framework has been formulated to improve the design in a systematic way with higher accuracy. Based on this design framework, parameter optimization has been carried out, and a quantitative design with enhanced performance has been proposed. Preliminary work on fabrication and testing setup has been done to prepare for the future experimental verification of the new design.
by Ruize Xu.
S.M.
Xiong, Xingyu. "Development of vibration-based multi-resonance energy harvesters using piezoelectric materials." Thesis, University of Manchester, 2014. https://www.research.manchester.ac.uk/portal/en/theses/development-of-vibrationbased-multiresonance-energy-harvesters-using-piezoelectric-materials(62d0d760-8b9c-4958-94a9-677b0e57082d).html.
Full textZhang, Hanlu. "Modeling, simulation, and optimization of miniature tribo-electret kinetic energy harvesters." Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLC100.
Full textHarvesting energy from the ambient environment is a good sustainable and complementary power supply solution in some consumer electronics, distributed wireless sensor networks, wearable or implantable devices, "Internet of Things" systems with lots of nodes, etc. in comparison with batteries. The ubiquitous kinetic energy in various motions and vibrations is one of the most available energy sources for such a purpose. The electret kinetic energy harvesters (E-KEHs) is one type of electrostatic kinetic energy harvesters using electrets (dielectrics with quasi-permanent charges) as the biasing voltage source, which can generate electricity based on the electrostatic induction effect when the capacitance of the E-KEHs is changed by the motions/vibrations. This thesis aims to investigate the transitory output characteristics of E-KEHs by both theoretical simulations and experimental measurements and to optimize the efficiency and output power of E-KEHs by tribo-charging and other methods adapted to their output characteristics, which are significant to improving the performance of E-KEHs.Firstly, the amplitude-variable output characteristics of a contact-separation (CS) mode E-KEH in transitory working cycles are investigated via the simulation results based on a detailed equivalent circuit model. These amplitude-variable output characteristics are attributed to the lag of the charge-transfer cycle behind the excitation motion cycle. The influences of both the initial condition and the load resistance on the variation in the output voltage peaks of a tribo-electret KEH (TE-KEH) are studied in detail and verified by both simulated and experimental data of a CS mode TE-KEH made with polytetrafluoroethylene (PTFE) electret film.Secondly, based on the analysis of the amplitude-variable output characteristics, a contact time optimization method is used to improve the output power and efficiency of the CS mode TE-KEH with a large load resistance of 100 MΩ. The theoretical maximum output energy per working cycle of the TE-KEH is analyzed. Several usually unfavorable factors that would reduce the practical output energy per working cycle of the TE-KEH are discussed. The maximum air gap optimization and the tribo-charging methods are also used together to further improve the average output power of the 4 cm × 4 cm sized TE-KEH from ~150 μW to ~503 μW.Thirdly, an innovative and facile tape-peeling tribo-charging method is developed to charge the fluorinated ethylene propylene (FEP) polymer film to make electrets without using any high voltage source. The surface potential distribution of the FEP film is apparently changed after several tape-peeling tribo-charging treatments. Consequently, the output voltage and current of TE-KEHs made with the FEP film are greatly improved. For a 64 cm2 sized flexible TE-KEH to harvest kinetic energy from wind, an apparent ~692% improvement in the output power from ~2.5 μW to ~19.8 μW was obtained by the tape-peeling charging method
Sunduza, Nosipho Gloria. "Poverty alleviation through the development of subsistence harvesters at Ngqushwa Municipality." Thesis, Nelson Mandela Metropolitan University, 2017. http://hdl.handle.net/10948/9228.
Full textGorial, Bassim Yousif. "Pneumatic methods for the separation of grain and straw." Thesis, University of Newcastle Upon Tyne, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.315609.
Full textGoroski, John Michael. "Effects of taxes and age on depreciation: the case of combine harvesters." Thesis, Montana State University, 1990. http://etd.lib.montana.edu/etd/1990/goroski/GoroskiJ1990.pdf.
Full textWilsey, David Scott. "Business or pleasure : factors motivating northern Minnesota non-timber forest product harvesters /." Diss., ON-CAMPUS Access for University of Minnesota, Twin Cities Click on "Connect to Digital Dissertations, 2002. http://www.lib.umn.edu/articles/proquest.phtml.
Full textFaisal, Farjana. "Towards the use of piezoelectric energy harvesters in pavement with passing vehicles." SPIE, 2017. http://hdl.handle.net/1993/32084.
Full textFebruary 2017
Galbier, Antonio Costante. "Investigation of the Interaction between Energy Harvesters in Pacemakers and the Heart." Thesis, State University of New York at Buffalo, 2017. http://pqdtopen.proquest.com/#viewpdf?dispub=10255430.
Full textEmbedded piezoelectric energy harvesting (PEH) systems in medical pacemakers have been an attractive and well visited research area. These systems typically utilize different configurations of beam structures with forcing originating from heart beat oscillations. The goal of these systems, at present, is to remove the pacemaker battery, which makes up 60-80% of the unit, and replace it with a sustainable and self-reliant power option. This requires that the energy harvesting system provide sufficient power, 1-3?W, for operating a pacemaker. With emerging technologies encouraging a push towards leadless pacemakers; typical energy harvesting beam structures are becoming inherently coupled with the heart system. The goal of this work is to develop, test, and simulate cantilevered energy harvesters with a linear elastic magnifier (LEM). This research hopes to provide insight into the interaction between pacemaker energy harvesters and the heart. By introducing the elastic magnifier into linear and nonlinear systems oscillations of the tip are encouraged into high energy orbits and large tip deflections. A continuous nonlinear model is derived for the bistable piezoelectric energy harvesting (BPEH) system and a one-degree-of-freedom linear mass-spring-damper model is derived for the elastic magnifier. The elastic magnifier will not consider the damping negligible due to the viscous nature of the heart, unlike most models. For experimental testing a physical model was created for the bistable structure and fashioned to an elastic magnifier. A hydrogel was chosen as the physical model for the LEM. Experimental results have shown that the bistable piezoelectric energy harvester coupled with a linear elastic magnifier (BPEH+LEM) produces more power at certain input frequencies and operates a larger bandwidth than a PEH, BPEH, and a standard piezoelectric energy harvester with the elastic magnifier (PEH+LEM). Numerical simulations were validated by these results showing that the system enters high-energy and high orbit oscillations. It has been shown that BPEH systems implemented in medical pacemakers can have enhanced performance if positioned over the heart.
Massaguer, Colomer Eduard. "Advances in the modelling of thermoelectric energy harvesters in waste heat recovery applications." Doctoral thesis, Universitat de Girona, 2016. http://hdl.handle.net/10803/398612.
Full textEn aquest treball s’investiga la recuperació termoelèctrica en xarxes de fluids i es proposa una eina genèrica per a la simulació i dimensionament de recuperadors termoelèctrics, els quals, poden ser utilitzats en aplicacions industrials per convertir l'energia tèrmica residual en electricitat. Els models actuals que es troben en la literatura es basen sovint en aplicacions molt específiques o són massa generals per analitzar realment el comportament de recuperadors en aplicacions reals. El model desenvolupat en aquest treball és altament adaptable pel que permet estudiar un gran nombre de sistemes diferents. S’ha desenvolupat un model teòric per estimar amb precisió l'energia recuperada tenint en compte les no linealitats de les equacions termoelèctriques i de transferència de calor. Tenint en compte que un recuperador termoelèctric comprèn sempre múltiples mòduls termoelèctrics col·locats en respecte a la direcció de flux, ambdues configuracions sèrie-paral·lel tant la tèrmica com l’elèctrica s'han considerat. El nou model ha estat analitzat i validat sota diversos estats estacionaris i transitoris a partir de dades experimentals. El model de recuperador proposat s’ha codificat per tal de treballar en l’entorn TRNSYS, de manera que pot ser utilitzat en el disseny i optimització de recuperadors termoelèctrics, és fàcilment escalable, permet atendre a una gran varietat d'aplicacions i requisits i, per tant, ajudar a la seva implantació en aplicacions reals. Aquest mòdul servirà per predir el comportament de recuperadors de calor termoelèctrics aplicats en sistemes tèrmics convencionals
Christie, Candice Jo-Anne. "A field investigation of physical workloads imposed on harvesters in South African forestry." Thesis, Connect to this title online, 2006. http://eprints.ru.ac.za/246/.
Full textLeicht, Joachim [Verfasser], and Yiannos [Akademischer Betreuer] Manoli. "CMOS circuits for electromagnetic vibration energy harvesters : : system modeling, interface design and implementation." Freiburg : Universität, 2019. http://d-nb.info/1193423090/34.
Full textHinchet, Ronan. "Electromechanical study of semiconductor piezoelectric nanowires. Application to mechanical sensors and energy harvesters." Thesis, Grenoble, 2014. http://www.theses.fr/2014GRENT013/document.
Full textSmart systems are the combined result of different advances in microelectronics leading to an increase in computing power, lower energy consumption, the addition of new features, means of communication and especially its integration and application into our daily lives. The evolution of the field of smart systems is promising, and the expectations are high in many fields: Industry, transport, infrastructure and environment monitoring as well as housing, consumer electronics, health care services but also defense and space applications. Nowadays, the integration of more and more functions in smart systems is leading to a looming energy issue where the autonomy of such smart systems is beginning to be the main issue. Therefore there is a growing need for autonomous sensors and power sources. Developing energy harvesters and self-powered sensors is one way to address this energy issue. Among the technologies studied, piezoelectricity has the advantage to be compatible with the MEMS industry, it generates high voltages and it has a high direct coupling between the mechanic and electric physics. Among the piezoelectric materials, semiconductor piezoelectric nanowires (NWs) could be a promising option as they exhibit improved piezoelectric properties and higher maximum flexion.Among the different piezoelectric NWs, ZnO and GaN NWs are the most studied, their piezoelectric properties are more than doubled at the nanoscale. They have the advantage of being IC compatible and reasonably synthesizable by top-down and bottom-up approaches. Especially we studied the hydrothermal growth of ZnO NWs. In order to use them we studied the behavior of ZnO NWs. We performed analytical study and FEM simulations of a ZnO NW under bending. This study explains the piezoelectric potential distribution as a function of the force and is used to extract the scaling rules. We have also developed mechanical AFM characterization of the young modulus of ZnO and GaN NWs. Following we perform piezoelectric AFM characterization of these NWs, verifying the behavior under bending stresses. Once physics understood, we discuss limitation of our piezoelectric NWs models and a more realistic model is developed, closer to the experimental configurations. Using this model we evaluated the use of ZnO NW for force and displacement sensors by measuring the potential generated, and from experiments, the use of GaN NW for force sensor by measuring the current through the NW. But energy harvesting is also necessary to address the energy issue and we deeper investigate this solution. To fully understand the problematic we study the state of the art of nanogenerator (NG) and their potential architectures. We analyze their advantages and disadvantages in order to define a reference NG structure. After analytical study of this structure giving the basis for a deeper understanding of its operation and challenges, FEM simulations are used to define optimization routes for a NG working in compression or in bending. The fabrication of prototypes and theirs preliminary characterization is finally presented
Heymanns, Matthias. "Multistable Structures for Broad Bandwidth Vibration-based Energy Harvesters: An Analytical Design Investigation." Phd thesis, Studienbereich Mechanik, Technische Universität Darmstadt, 2015. https://tuprints.ulb.tu-darmstadt.de/5333/1/Dissertation_Heymanns.pdf.
Full textAponte, Erick. "A Study on Energy Harvesters for Physical Unclonable Functions and Random Number Generation." Thesis, Virginia Tech, 2017. http://hdl.handle.net/10919/78673.
Full textMaster of Science
Turner, John Andrew. "A New Approach to Wide Bandwidth Energy Harvesting for Piezoelectric Cantilever Based Harvesters." Thesis, Virginia Tech, 2013. http://hdl.handle.net/10919/19301.
Full textMaster of Science
Schroeder, Christopher. "Exploiting Collective Effects to Direct Light Absorption in Natural and Artificial Light-Harvesters." Thesis, University of Maryland, College Park, 2016. http://pqdtopen.proquest.com/#viewpdf?dispub=10128741.
Full textPhotosynthesis—the conversion of sunlight to chemical energy—is fundamental for supporting life on our planet. Despite its importance, the physical principles that underpin the primary steps of photosynthesis, from photon absorption to electronic charge separation, remain to be understood in full. Electronic coherence within tightly-packed light-harvesting (LH) units or within individual reaction centers (RCs) has been recognized as an important ingredient for a complete understanding of the excitation energy transfer (EET) dynamics. However, the electronic coherence across units—RC and LH or LH and LH—has been consistently neglected as it does not play a significant role during these relatively slow transfer processes. Here, we turn our attention to the absorption process, which, as we will show, has a much shorter built-in timescale. We demonstrate that the—often overlooked—spatially extended but short-lived excitonic delocalization plays a relevant role in general photosynthetic systems. Most strikingly, we find that absorption intensity is, quite generally, redistributed from LH units to the RC, increasing the number of excitations which can effect charge separation without further transfer steps. A biomemetic nano-system is proposed which is predicted to funnel excitation to the RC-analogue, and hence is the first step towards exploiting these new design principles for efficient artificial light-harvesting.
Rahimi, Arian. "Design And Implementation Of Low Power Interface Electronics For Vibration-based Electromagnetic Energy Harvesters." Master's thesis, METU, 2011. http://etd.lib.metu.edu.tr/upload/12613820/index.pdf.
Full text10 Hz), where most vibrations exits. However, since the generated EM power and voltage is relatively low at low frequencies, high performance interface electronics is required for efficiently transferring the generated power from the harvester to the load to be supplied. The aim of this study is to design low power and efficient interface electronics to convert the low voltage and low power generated signals of the EM energy harvesters to DC to be usable by a real application. The most critical part of such interface electronics is the AC/DC converter, since all the other blocks such as DC/DC converters, power managements units, etc. rely on the rectified voltage generated by this block. Due to this, several state-of-the-art rectifier structures suitable for energy harvesting applications have been studied. Most of the previously proposed rectifiers have low conversion efficiency due to the high voltage drop across the utilized diodes. In this study, two rectifier structures are proposed: one is a new passive rectifier using the Boot Strapping technique for reducing the diode turn-on voltage values
the other structure is a comparator-based ultra low power active rectifier. The proposed structures and some of the previously reported designs have been implemented in X-FAB 0.35 µ
m standard CMOS process. The autonomous energy harvesting systems are then realized by integrating the developed ASICs and the previously proposed EM energy harvester modules developed in our research group, and these systems have been characterized under different electromechanical excitation conditions. In this thesis, five different systems utilizing different circuits and energy harvesting modules have been presented. Among these, the system utilizing the novel Boot Strap Rectifier is implemented within a volume of 21 cm3, and delivers 1.6 V, 80 µ
A (128 µ
W) DC power to a load at a vibration frequency of only 2 Hz and 72 mg peak acceleration. The maximum overall power density of the system operating at 2 Hz is 6.1 µ
W/cm3, which is the highest reported value in the literature at this operation frequency. Also, the operation of a commercially available temperature sensor using the provided power of the energy harvester has been shown. Another system utilizing the comparator-based active rectifier implemented with a volume of 16 cm3, has a dual rail output and is able to drive a 1.46 V, 37 µ
A load with a maximum power density of 6.03 µ
W/cm3, operating at 8 Hz. Furthermore, a signal conditioning system for EM energy harvesting has also been designed and simulated in TSMC 90 nm CMOS process. The proposed ASIC includes a highly efficient AC-DC converter as well as a power processing unit which steps up and regulates the converted DC voltages using an on-chip DC/DC converter and a sub-threshold voltage regulator with an ultra low power management unit. The total power consumption on the totally passive IC is less than 5 µ
W, which makes it suitable for next generation MEMS-based EM energy harvesters. In the frame of this study, high efficiency CMOS rectifier ICs have been designed and tested together with several vibration based EM energy harvester modules. The results show that the best efficiency and power density values have been achieved with the proposed energy harvesting systems, within the low frequency range, to the best of our knowledge. It is also shown that further improvement of the results is possible with the utilization of a more advanced CMOS technology.
Li, Yang. "Scene Recognition and Collision Avoidance System for Robotic Combine Harvesters Based on Deep Learning." Kyoto University, 2020. http://hdl.handle.net/2433/259052.
Full textSewell, Andrew J. "Multirole power units in cereal harvesting : an economic case for adoption." Thesis, University of Newcastle Upon Tyne, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.295107.
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