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You searched for subject:(energy harnessing materials). Showing records 1 – 3 of 3 total matches.

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University of Minnesota

1. Wang, Guojun. Piezoelectric energy harvesting utilizing human locomotion.

Degree: MS, Electrical Engineering, 2010, University of Minnesota

University of Minnesota M.S. thesis. July 2010. Major: Electrical Engineering. Advisor: William P. Robbins. 1 computer file (PDF); xii, 100 pages, appendices A-B. Ill. (some col.)

Previous studies have shown that not only are piezoelectric materials feasible for energy harvesting, they are feasible as an energy harnessing medium in shoes during walking. Continuing in that vein, this thesis provides new designs to better apply mechanical stress and achieve higher power output. Two points of stress during walking were used for energy harvesting. 1.) The heel of the shoe, for when a person’s foot first lands on the ground during the initial stage of the step. 2.) The ball of the shoe, for the curling motioning of the foot as the person propels forward finishing a step. A flexible, multilayered insole was developed for the ball of the shoe operation and integration into the sole of a specially selected “street shoes”. The insole consists of six layers of PVDF sheets, three sheets per side, adhered to a thick but flexible Nylon core. The PVDF absorbs the mechanical compression or tension stress, depending on the side they are on, thereby creating a charge differential across the surface of each sheet. A rigid, reversed clamshell piezoceramic transducer was developed and integrated into the heel of the same shoe. The insert consists of two Thunder PZT unimorph connected in parallel and mounted inside a steel housing to facilitate optimal force transference. The inherent capacitive property of the piezoelectric materials and its very low frequency of operation (~ 1Hz or 1 step per second), allows for very little current to be extracted through conventional full-wave rectifier harvesting circuit. Due to previous research success with resonating an inductor in series with the piezoelectric source, an energy harvesting circuit coined “Synchronized Switch Harvesting on Inductor” SSHI was utilized to increase power output. However, due to the inability to correctly synchronize the switching circuit and lack of proper piezoelectric source modeling, SSHI circuit only provided marginal improvement in power output ~10-20% as oppose to previous study demonstrating 250%+ output. Nevertheless, by using only full-wave rectifier harvesting circuits, the new PVDF insole and PZT insert designs have propelled harvestable energy to 11-13mW from one shoe, with a combined generation of 22-26mW for both shoes.

Advisors/Committee Members: William P. Robbins.

Subjects/Keywords: Piezoelectric materials; Energy harnessing; Shoe; Mechanical compression; Circuit; Electrical Engineering

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Wang, G. (2010). Piezoelectric energy harvesting utilizing human locomotion. (Masters Thesis). University of Minnesota. Retrieved from http://purl.umn.edu/93638

Chicago Manual of Style (16th Edition):

Wang, Guojun. “Piezoelectric energy harvesting utilizing human locomotion.” 2010. Masters Thesis, University of Minnesota. Accessed October 21, 2019. http://purl.umn.edu/93638.

MLA Handbook (7th Edition):

Wang, Guojun. “Piezoelectric energy harvesting utilizing human locomotion.” 2010. Web. 21 Oct 2019.

Vancouver:

Wang G. Piezoelectric energy harvesting utilizing human locomotion. [Internet] [Masters thesis]. University of Minnesota; 2010. [cited 2019 Oct 21]. Available from: http://purl.umn.edu/93638.

Council of Science Editors:

Wang G. Piezoelectric energy harvesting utilizing human locomotion. [Masters Thesis]. University of Minnesota; 2010. Available from: http://purl.umn.edu/93638


University of Minnesota

2. Wang, Guojun. Piezoelectric energy harvesting utilizing human locomotion.

Degree: MS, Electrical Engineering, 2010, University of Minnesota

Previous studies have shown that not only are piezoelectric materials feasible for energy harvesting, they are feasible as an energy harnessing medium in shoes during walking. Continuing in that vein, this thesis provides new designs to better apply mechanical stress and achieve higher power output. Two points of stress during walking were used for energy harvesting. 1.) The heel of the shoe, for when a person’s foot first lands on the ground during the initial stage of the step. 2.) The ball of the shoe, for the curling motioning of the foot as the person propels forward finishing a step. A flexible, multilayered insole was developed for the ball of the shoe operation and integration into the sole of a specially selected “street shoes”. The insole consists of six layers of PVDF sheets, three sheets per side, adhered to a thick but flexible Nylon core. The PVDF absorbs the mechanical compression or tension stress, depending on the side they are on, thereby creating a charge differential across the surface of each sheet. A rigid, reversed clamshell piezoceramic transducer was developed and integrated into the heel of the same shoe. The insert consists of two Thunder PZT unimorph connected in parallel and mounted inside a steel housing to facilitate optimal force transference. The inherent capacitive property of the piezoelectric materials and its very low frequency of operation (~ 1Hz or 1 step per second), allows for very little current to be extracted through conventional full-wave rectifier harvesting circuit. Due to previous research success with resonating an inductor in series with the piezoelectric source, an energy harvesting circuit coined “Synchronized Switch Harvesting on Inductor” SSHI was utilized to increase power output. However, due to the inability to correctly synchronize the switching circuit and lack of proper piezoelectric source modeling, SSHI circuit only provided marginal improvement in power output ~10-20% as oppose to previous study demonstrating 250%+ output. Nevertheless, by using only full-wave rectifier harvesting circuits, the new PVDF insole and PZT insert designs have propelled harvestable energy to 11-13mW from one shoe, with a combined generation of 22-26mW for both shoes.

Subjects/Keywords: Piezoelectric materials; Energy harnessing; Shoe; Mechanical compression; Circuit; Electrical Engineering

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Wang, G. (2010). Piezoelectric energy harvesting utilizing human locomotion. (Masters Thesis). University of Minnesota. Retrieved from http://purl.umn.edu/93638

Chicago Manual of Style (16th Edition):

Wang, Guojun. “Piezoelectric energy harvesting utilizing human locomotion.” 2010. Masters Thesis, University of Minnesota. Accessed October 21, 2019. http://purl.umn.edu/93638.

MLA Handbook (7th Edition):

Wang, Guojun. “Piezoelectric energy harvesting utilizing human locomotion.” 2010. Web. 21 Oct 2019.

Vancouver:

Wang G. Piezoelectric energy harvesting utilizing human locomotion. [Internet] [Masters thesis]. University of Minnesota; 2010. [cited 2019 Oct 21]. Available from: http://purl.umn.edu/93638.

Council of Science Editors:

Wang G. Piezoelectric energy harvesting utilizing human locomotion. [Masters Thesis]. University of Minnesota; 2010. Available from: http://purl.umn.edu/93638


University of Waterloo

3. Nandihalli, Nagaraj. Ni₀.₀₅Mo₃Sb₅.₄Te₁.₆ Based Thermoelectric Nanocomposites.

Degree: 2016, University of Waterloo

Thermoelectric (TE) materials have the capability to convert thermal energy into useful electrical energy. Sustainable energy production and its utilization are among the many challenges that humankind is facing today. In 2016 and 2017, the expected global production of hydrocarbon based automotive vehicles is expected to be 97.8 and 101.8 million respectively, and is expected to rise. The collective thermal energy losses from radiators and exhausts from these automotive vehicles are enormous. This is a big bottleneck in sustainable energy production and utilization. In mitigating this hurdle, TE materials will play a very important role. However, TE materials have low efficiency in thermal to electrical energy conversion owing to the reciprocal relation between the thermal and the electrical transport properties. Recent advances in nanotechnology tools have given a new dimension to decouple this relation. Back in 2003, our group reported a very promising TE material, NiyMo3Sb5.4Te1.6 (y < 0.1). Improving the figure-of-merit of Ni0.05Mo3Sb5.4Te1.6 (“bulk”) material through nanocomposite synthesis is one of the goals of my research. The main outcome of nanocomposite synthesis is the reduced thermal conductivity through arresting the coherent propagation of heat carrying acoustic waves in TE materials. To this end, I synthesized and characterized the transport properties of various nanocomposites. I have used fullerenes, oxides, carbides, and metal particles to fabricate nanocomposites. Chapter 3 addresses the effect of multi-wall carbon nanotubes (MWCNT) when added to Ni0.05Mo3Sb5.4Te1.6. We characterized these samples for their TE properties, and addressed the effect of porosity on transport properties. The effect of ball-milling on MWCNT was studied. Scanning and transmission electron microscopy were used to study the microstructural and nanostructural features of the samples. In a sample with 3 mass-% of MWCNT, the main contributing factor in elevating the figure-of-merit by 25% was the reduction in the thermal conductivity by 40%. In Chapter 4, we reported the results of Ni0.05Mo3Sb5.4Te1.6 /SiC and Ni0.05Mo3Sb5.4Te1.6/Al2O3 composites consolidated through hot-pressing and spark-plasma sintering respectively. Samples with different volume fractions of SiC were prepared and characterized. Thermoelectric transport properties of these composites were characterized from 325 K to 740 K. For the sample with 0.01volume fraction of SiC, there was an enhancement in the figure-of-merit by an 18% compared to the reference sample, mainly due to an 18% reduction in the thermal conductivity. Microstructural information obtained through SEM, TEM, and BET was used to elucidate phase and transport properties. Spark-plasma sintered bulk sample has exhibited the highest figure-of-merit, which is 35% higher than the bulk consolidated through hot-pressing. Pore effect on thermal conductivity and electrical conductivity were investigated. In Chapter 5, we covered various properties of bulk/NiSb composite. In this study, requisite…

Subjects/Keywords: thermoelectric materials; thermoelectric nanocomposites; energy harnessing materials; thermoelectric generators; thermal transport properties; electrical transport properties; porous materials; surface area of materials; effective media theories; nanocoating

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Nandihalli, N. (2016). Ni₀.₀₅Mo₃Sb₅.₄Te₁.₆ Based Thermoelectric Nanocomposites. (Thesis). University of Waterloo. Retrieved from http://hdl.handle.net/10012/10442

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16th Edition):

Nandihalli, Nagaraj. “Ni₀.₀₅Mo₃Sb₅.₄Te₁.₆ Based Thermoelectric Nanocomposites.” 2016. Thesis, University of Waterloo. Accessed October 21, 2019. http://hdl.handle.net/10012/10442.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

Nandihalli, Nagaraj. “Ni₀.₀₅Mo₃Sb₅.₄Te₁.₆ Based Thermoelectric Nanocomposites.” 2016. Web. 21 Oct 2019.

Vancouver:

Nandihalli N. Ni₀.₀₅Mo₃Sb₅.₄Te₁.₆ Based Thermoelectric Nanocomposites. [Internet] [Thesis]. University of Waterloo; 2016. [cited 2019 Oct 21]. Available from: http://hdl.handle.net/10012/10442.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Nandihalli N. Ni₀.₀₅Mo₃Sb₅.₄Te₁.₆ Based Thermoelectric Nanocomposites. [Thesis]. University of Waterloo; 2016. Available from: http://hdl.handle.net/10012/10442

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

.