Advanced search options

Advanced Search Options 🞨

Browse by author name (“Author name starts with…”).

Find ETDs with:

in
/  
in
/  
in
/  
in

Written in Published in Earliest date Latest date

Sorted by

Results per page:

Sorted by: relevance · author · university · dateNew search

You searched for +publisher:"University of Notre Dame" +contributor:("Dani Meisel, Committee Member"). Showing records 1 – 3 of 3 total matches.

Search Limiters

Last 2 Years | English Only

No search limiters apply to these results.

▼ Search Limiters


University of Notre Dame

1. Benjamin Highsmith Meekins. Controlling Interfacial Transfer Processes For Improved Photoelectrochemical Performance</h1>.

Degree: Chemical Engineering, 2012, University of Notre Dame

As the Earth’s population continues to grow exponentially and become more technologically advanced, fossil fuel prices rise concurrently, a reflection of the diminishing resources available at a reasonable price and with reasonable effort. A significant part of the solution to this energy problem is to utilize renewable energy resources" wind, hydroelectric, geothermal, and solar, among others. The amount of solar energy reaching the surface of the Earth each day is orders of magnitude more than the energy needs of all the people of the world combined. An important question, however, immediately arises: how can excess energy be stored to power homes when the sun goes down? Hydrogen is an excellent candidate as a storage medium. It can be used in current internal combustion engines, and it can be stored in pressurized tanks or metal hydrides for ease of access and transportation. Currently, the vast majority (approximately 95%) of hydrogen is produced at a net energy loss from steam-methane reforming. To be useful as an energy carrier, hydrogen must be produced using a “free” energy input like sunlight. Following Fujishima and Honda’s demonstration of photolysis of water on TiO2 using simulated sunlight in 1972, the field of water photolysis and hydrogen generation has grown quickly. In this dissertation, improvement of photoelectrochemical performance by intercalation of Li+ to passivate Ti4+ trap states have been demonstrated. This passivation increases both the photovoltage and photocurrent generated by increasing the rate of collection of photogenerated electrons. Pulsed laser deposition was used to synthesize metal oxide heterostructures while retaining an excellent electron conducting substrate has also been demonstrated, and this SrTiO3-TiO2 heterostructure was observed to enhance photoelectrochemical performance due to an increase in charge separation. IrO2, a widely studied water oxidation catalyst that has the lowest overpotential for the oxygen evolution reaction, was shown to catalyze an undesirable side reaction on TiO2. The scavenging of trapped holes by reduced oxygen radicals was enabled only in the presence of IrO2, and this scavenging occurred on a timescale approximately 1000 times faster than that of water oxidation, which means that it represents a serious obstacle to developing a water photolysis system that does not rely on external power input. Continuous hydrogen generation in a reverse fuel cell has been demonstrated using CdS on TiO2, and the quantum efficiency of the reaction has been determined using chemical actinometry, demonstrating that calculation of efficiency based on current-voltage characteristics is insufficient. Based on the research presented in this dissertation, future directions to pursue are also discussed. Advisors/Committee Members: Dr. Paul McGinn, Committee Member, Dr. Alexander Mukasyan, Committee Member, Dr. Prashant Kamat, Committee Chair, Dr. Dani Meisel, Committee Member.

Subjects/Keywords: iridium oxide; water oxidation; solar; solar hydrogen generation; water reduction; TiO2; IrO2; solar cell; solar energy; water splitting; solar hydrogen; hydrogen; hydrogen generation; solar generation; titanium dioxide

Record DetailsSimilar RecordsGoogle PlusoneFacebookTwitterCiteULikeMendeleyreddit

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

APA (6th Edition):

Meekins, B. H. (2012). Controlling Interfacial Transfer Processes For Improved Photoelectrochemical Performance</h1>. (Thesis). University of Notre Dame. Retrieved from https://curate.nd.edu/show/b2773t9673p

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):

Meekins, Benjamin Highsmith. “Controlling Interfacial Transfer Processes For Improved Photoelectrochemical Performance</h1>.” 2012. Thesis, University of Notre Dame. Accessed July 09, 2020. https://curate.nd.edu/show/b2773t9673p.

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

MLA Handbook (7th Edition):

Meekins, Benjamin Highsmith. “Controlling Interfacial Transfer Processes For Improved Photoelectrochemical Performance</h1>.” 2012. Web. 09 Jul 2020.

Vancouver:

Meekins BH. Controlling Interfacial Transfer Processes For Improved Photoelectrochemical Performance</h1>. [Internet] [Thesis]. University of Notre Dame; 2012. [cited 2020 Jul 09]. Available from: https://curate.nd.edu/show/b2773t9673p.

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

Council of Science Editors:

Meekins BH. Controlling Interfacial Transfer Processes For Improved Photoelectrochemical Performance</h1>. [Thesis]. University of Notre Dame; 2012. Available from: https://curate.nd.edu/show/b2773t9673p

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


University of Notre Dame

2. Charles F Vardeman II. Computational Studies of Metallic Glasses and Nanoparticles</h1>.

Degree: Chemistry and Biochemistry, 2009, University of Notre Dame

This dissertation presents research using classically based Molecular Dynamics techniques to study the structure and dynamics of phases exhibited by unique metallic systems. These systems include metallic glasses, nanoparticles, and lastly glassy nanoparticles. It is arranged in the order the research was conducted since later material builds on formerly presented materials. Introductory material common to all chapters in this dissertation relating to Molecular Dynamics techniques is presented in the opening chapter. This includes an introduction to metallic force fields, integration of the classical equations of motion and Langevin Dynamics. Chapter 2 explores transport dynamics in a known glass former (a mixture of silver and copper). This system presents an interesting target for computational study because it is a real glass forming system that closely resembles model binary Lennard-Jones systems that have been previously studied. Lennard-Jones glasses are interesting because they have decay functions that obey the Kohlrausch-Williams-Watts (KWW) law. Comparisons will be made between dynamics (mean squared displacement, cage correlation funcion) in model systems and models of real glass formers. Additionally, a model for fractal distributions of waiting times in glassy materials will be examined and compared to the waiting times in this metallic glass. It has been experimentally observed that spontaneous alloying of bimetallic core-shell Au-Ag nanoparticles (NPs) can occur shortly after synthesis. Chapter 3 will use computational techniques to explore a possible mechanism for such alloying. Nanoparticles differ in many ways from their bulk counterparts in both physical and chemical properties. Some of these differences are attributed to the large surface area to volume ration present in nanoparticles. Computational techniques will be used to explore whether the hypothesis that a small fraction of vacancies formed at the Au-Ag core-shell interface, during synthesis, can result in the alloying of the nanoparticle. And, if this alloying occurs on a time scale consistent with experimental observations. Chapter 4 computationally explores experimental observations involving the transient response of metallic nanoparticles to the nearly instantaneous heating undergone when photons are absorbed during ultrafast laser excitation experiments. Because the time scale for heating is faster than a single period of the breathing mode for spherical nanoparticles, hot-electron pressure and lattice heating contribute to thermal excitation of the lattice. Both mechanism are rapid enough to coherently excite the breathing mode of the spherical particles. Molecular Dynamics simulations are used to replicate the laser-excitation event allowing the nanoparticle dynamics to be probed after excitation. It was observed during the studies of metallic nanoparticles dissused on in Chapter 4 that the time scale for the cooling of these particle is very short (on the order of tens of… Advisors/Committee Members: Dani Meisel, Committee Member, Ian C. Charmichael, Committee Member, S. Alex Kandel, Committee Member, J. Daniel Gezelter, Committee Chair.

Subjects/Keywords: molecular dynamics; computational simulation; glassy nanoparticles; metallic potentials; metallic glasses; langevin dynamics; metallic nanoparticles

Record DetailsSimilar RecordsGoogle PlusoneFacebookTwitterCiteULikeMendeleyreddit

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

APA (6th Edition):

II, C. F. V. (2009). Computational Studies of Metallic Glasses and Nanoparticles</h1>. (Thesis). University of Notre Dame. Retrieved from https://curate.nd.edu/show/df65v694x2h

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):

II, Charles F Vardeman. “Computational Studies of Metallic Glasses and Nanoparticles</h1>.” 2009. Thesis, University of Notre Dame. Accessed July 09, 2020. https://curate.nd.edu/show/df65v694x2h.

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

MLA Handbook (7th Edition):

II, Charles F Vardeman. “Computational Studies of Metallic Glasses and Nanoparticles</h1>.” 2009. Web. 09 Jul 2020.

Vancouver:

II CFV. Computational Studies of Metallic Glasses and Nanoparticles</h1>. [Internet] [Thesis]. University of Notre Dame; 2009. [cited 2020 Jul 09]. Available from: https://curate.nd.edu/show/df65v694x2h.

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

Council of Science Editors:

II CFV. Computational Studies of Metallic Glasses and Nanoparticles</h1>. [Thesis]. University of Notre Dame; 2009. Available from: https://curate.nd.edu/show/df65v694x2h

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


University of Notre Dame

3. Vladimir Protasenko. Electro-optical properties of CdSe nanowires</h1>.

Degree: Chemistry and Biochemistry, 2008, University of Notre Dame

This Thesis describes the results of electro-optical experiments performed on solution grown CdSe nanowires (NWs). TEM images reveal that such NWs have diameters between 6-40 nm, are highly crystalline and exhibit large aspect ratios (>1000, length/diameter). The morphologies of these NWs range from straight to hyper-branched. Absorption cross-sections determine how efficiently a material absorbs light. In this Thesis we calculate single NW absorption cross-sections based on UV-VIS linear extinction, TEM, and inductively coupled plasma atomic emission spectroscopy experiments. Obtained numbers compare well with theoretical estimates, having order of magnitude values of 10-11 cm2 per 1 Ìåm length of a 10 nm diameter NW. Synthesized CdSe NWs are emissive and are easily detectable at the single wire level. A surprising observation from these experiments is the modulation of the NW emission intensity by applied electrical fields. Specifically, the part of the wire closest to the positive electrode exhibits up to a 10x increase in intensity. Simultaneous quenching of identical magnitude is detected on the other side of the wire. Our current working hypothesis is that mobile electrons driven by the external electrical field passivate emission quenching centers resulting in local emission enhancement. Similarly, the smaller density of electrons on the other side of the wire yields emission quenching. To confirm the existence of these mobile carriers we perform electrophoresis measurements on NWs. Observed single wire translational and rotational dynamics can be explained by mobile carriers residing on or within the NWs. A lower limit for the carrier density of NWs in oleic acid is estimated to be ~1 charge/Ìåm. Since light absorption results in both NW emission as well as the photogeneration of carriers, photoconductivity measurements are also possible. While doing such measurements, we unexpectedly discovered that randomly oriented NW networks could exhibit a significant photocurrent polarization anisotropy with values of Ì=0.25 (Ì®Õ=0.04) under excitation with linearly polarized light. The remarkable conclusion from this result is that polarization sensitive devices can be built from random NW networks without the need to align component wires. To explain these results a simple geometric model has also been developed. Advisors/Committee Members: Dani Meisel, Committee Member, Steven Corcelli, Committee Member, Mark Alber, Committee Chair, Masaru Kuno, Committee Member, Gregory Hartland, Committee Member.

Subjects/Keywords: intermittency; nanowires; emission; CdSe; blinking

Record DetailsSimilar RecordsGoogle PlusoneFacebookTwitterCiteULikeMendeleyreddit

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

APA (6th Edition):

Protasenko, V. (2008). Electro-optical properties of CdSe nanowires</h1>. (Thesis). University of Notre Dame. Retrieved from https://curate.nd.edu/show/j098z89307g

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):

Protasenko, Vladimir. “Electro-optical properties of CdSe nanowires</h1>.” 2008. Thesis, University of Notre Dame. Accessed July 09, 2020. https://curate.nd.edu/show/j098z89307g.

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

MLA Handbook (7th Edition):

Protasenko, Vladimir. “Electro-optical properties of CdSe nanowires</h1>.” 2008. Web. 09 Jul 2020.

Vancouver:

Protasenko V. Electro-optical properties of CdSe nanowires</h1>. [Internet] [Thesis]. University of Notre Dame; 2008. [cited 2020 Jul 09]. Available from: https://curate.nd.edu/show/j098z89307g.

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

Council of Science Editors:

Protasenko V. Electro-optical properties of CdSe nanowires</h1>. [Thesis]. University of Notre Dame; 2008. Available from: https://curate.nd.edu/show/j098z89307g

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

.