subject:(magnetite Fe3O4)

You searched for subject:(magnetite Fe3O4). Showing records 1 – 4 of 4 total matches.

▼ Search Limiters

Georgia Tech

1. Minnici, Krysten. PEG-coated Fe3O4 for li-Ion battery anodes: Effects of crystallite size and surface chemistry.

Degree: MS, Chemical and Biomolecular Engineering, 2017, Georgia Tech

► Battery electrodes are complex mesoscale systems comprised of an active material, conductive agent, current collector, and polymeric binder. Previous work focused on enhancing electron and… (more)

▼ Battery electrodes are complex mesoscale systems comprised of an active material, conductive agent, current collector, and polymeric binder. Previous work focused on enhancing electron and ion transport in high capacity anode systems by introducing poly[3-(potassium-4- butanoate) thiophene] (PPBT) as a binder component and a polyethylene glycol (PEG) surface coating on magnetite (Fe3O4) nanoparticles. The PPBT/PEG system will be utilized in this work, which takes a closer look at the active material, Fe3O4, and examines the effects of surface chemistry and crystallite size (10 nm vs. 20 nm) on battery performance. Variations in surface chemistry are due to the synthesis methods used for Fe3O4, which use ammonium hydroxide or triethylamine as a base. XRD and TEM initially characterized the active materials to confirm the magnetite phase and crystallite size. DLS and zeta potential measurements demonstrated aggregate size and colloidal stability. SEM images of the electrodes, which are composed of Fe3O4 particles, carbon additives, and the PPBT binder, indicate that the bases produce different morphologies. The Fe3O4 particles synthesized with ammonium hydroxide appear more dispersed relative to those made with triethylamine, which could have a significant impact on the battery performance. Furthermore, XPS and FTIR data indicate that these bases produce difference chemical interactions within the electrode. Electrochemical testing demonstrates that the triethylamine-based electrode has a higher capacity and better capacity retention over 100 cycles at 0.3C as compared to the ammonium hydroxide-based electrode. With regards to differences in active material size, the electrodes with 20 nm crystallite size Fe3O4 initially have a higher capacity, but the electrodes with 10 nm crystallite size Fe3O4 have better capacity retention over 100 cycles at 0.3C. Rate capability testing and electrical impedance confirm the superior performance of triethylamine derived electrodes and the 10 nm crystallite size. Advisors/Committee Members: Reichmanis, Elsa (advisor), Fuller, Thomas (advisor), Meredith, Carson (advisor).

Subjects/Keywords: Li-ion battery; Anode; Fe3O4; Magnetite; PEG

Record Details Similar Records Cite « Share

❌

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

APA (6^th Edition):

Minnici, K. (2017). PEG-coated Fe3O4 for li-Ion battery anodes: Effects of crystallite size and surface chemistry. (Masters Thesis). Georgia Tech. Retrieved from http://hdl.handle.net/1853/59796

Chicago Manual of Style (16^th Edition):

Minnici, Krysten. “PEG-coated Fe3O4 for li-Ion battery anodes: Effects of crystallite size and surface chemistry.” 2017. Masters Thesis, Georgia Tech. Accessed January 16, 2021. http://hdl.handle.net/1853/59796.

MLA Handbook (7^th Edition):

Minnici, Krysten. “PEG-coated Fe3O4 for li-Ion battery anodes: Effects of crystallite size and surface chemistry.” 2017. Web. 16 Jan 2021.

Vancouver:

Minnici K. PEG-coated Fe3O4 for li-Ion battery anodes: Effects of crystallite size and surface chemistry. [Internet] [Masters thesis]. Georgia Tech; 2017. [cited 2021 Jan 16]. Available from: http://hdl.handle.net/1853/59796.

Council of Science Editors:

Minnici K. PEG-coated Fe3O4 for li-Ion battery anodes: Effects of crystallite size and surface chemistry. [Masters Thesis]. Georgia Tech; 2017. Available from: http://hdl.handle.net/1853/59796

2. XIAO WEN. MAGNETIC AND ELECTRICAL PROPERTIES OF MAGNETITE (FE3O4)-BASED FILMS AND DEVICES.

Degree: 2017, National University of Singapore

URL: http://scholarbank.nus.edu.sg/handle/10635/137661

Subjects/Keywords: Magnetite; Fe3O4; Film; Nanocolumn; RRAM; DFT

Record Details Similar Records Cite « Share

❌

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

APA (6^th Edition):

WEN, X. (2017). MAGNETIC AND ELECTRICAL PROPERTIES OF MAGNETITE (FE3O4)-BASED FILMS AND DEVICES. (Thesis). National University of Singapore. Retrieved from http://scholarbank.nus.edu.sg/handle/10635/137661

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

Chicago Manual of Style (16^th Edition):

WEN, XIAO. “MAGNETIC AND ELECTRICAL PROPERTIES OF MAGNETITE (FE3O4)-BASED FILMS AND DEVICES.” 2017. Thesis, National University of Singapore. Accessed January 16, 2021. http://scholarbank.nus.edu.sg/handle/10635/137661.

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

MLA Handbook (7^th Edition):

WEN, XIAO. “MAGNETIC AND ELECTRICAL PROPERTIES OF MAGNETITE (FE3O4)-BASED FILMS AND DEVICES.” 2017. Web. 16 Jan 2021.

Vancouver:

WEN X. MAGNETIC AND ELECTRICAL PROPERTIES OF MAGNETITE (FE3O4)-BASED FILMS AND DEVICES. [Internet] [Thesis]. National University of Singapore; 2017. [cited 2021 Jan 16]. Available from: http://scholarbank.nus.edu.sg/handle/10635/137661.

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

Council of Science Editors:

WEN X. MAGNETIC AND ELECTRICAL PROPERTIES OF MAGNETITE (FE3O4)-BASED FILMS AND DEVICES. [Thesis]. National University of Singapore; 2017. Available from: http://scholarbank.nus.edu.sg/handle/10635/137661

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

Luleå University of Technology

3. Karlsson, Christian A. M. Sensus Aquae in Ferrum ac Air : Karakterisering av elektriska egenskaper hos ett fuktmätnings system.

Degree: 2011, Luleå University of Technology

URL: http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-54848

►

Fast precise moisture measurement in mineral process plants, has long been a difficult problem. In this master thesis a foundation for a new way… (more)

▼

Fast precise moisture measurement in mineral process plants, has long been a difficult problem. In this master thesis a foundation for a new way of measurement using transmission line theory, is laid out. Macroscopic electro-magnetic properties of the measured sample can be linked to those of the individual constituents of the sample. Thus one is believed to be able to do a precise estimate of the amount of moisture in a sample. In our case the samples are moist magnetite concentrate. The characterization of sample macroscopic electro-magnetic properties is done by using a coaxial cell, performing frequency spectra measurement. In this master thesis, the electrical behavior that links the measured data to the macroscopic electro-magnetic properties is examined. It exists two setups, one inductive and one capacitive. The DC resistivity of the moist magnetite concentrate is determined and some interesting phenomena, suggested to be self potential were discovered. This phenomenon is in general known from geochemistry of mineral rich clays. This made the measurements of resistivity tricky to perform, some measurements were achieved and a new relation between moisture of the moist magnetite concentrate and resistivity is presented. Studies have been performed on the history of attempts of solving this problem, as well as current relevant research. Reference samples have been prepared in a geotechnical laboratory. Impedance frequency behavior of the measurement equipment is measured and presented, with different curves for different moisture content. From these measurements it is obvious that the moisture affects the impedance of the measurement equipment and thus it is possible to use this method to measure moisture content, if one can determine the electrical model which describes the measurement system. A few equivalent circuits of transmission lines have been discussed, and one was chosen to represent the purely coaxial part of the coaxial cell. Other parts have been modeled with other elements of AC theory. A new electrical model for the coaxial probe is proposed, based on LC resonances. Some Comsol FEM simulations have been performed on the coaxial cell, as well as on electric property sensors. Ideas to designs of electrical sensors are discussed. It is mainly the geometry which has been investigated. First it was proposed that a phenomenon of resonance occurs at the interface of the bottom and coaxial part of the cell, LC resonance. The resonance effect has later been investigated and identified as quarter wavelength resonance, due to the length of the measurement cell and change of wave velocity due to wave propagation in MUT. Simulations of proposed circuit equivalents in Orcad with PSpice have given some correlation with measured data for dry and non-conducting samples. There is still work to be done, to complete an accurate mathematical model of the system.

Validerat; 20110824 (anonymous)

Subjects/Keywords: Technology; Teknik; measurement; moisture; RF; electric permittivity; magnetic permeability; broad-band spectroscopy; frequency spectra; magnetite concentrate; Fe3O4; resistivity; equivalent circuits; coaxial cell; quarter wave resonance

Record Details Similar Records Cite « Share

❌

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

APA (6^th Edition):

Karlsson, C. A. M. (2011). Sensus Aquae in Ferrum ac Air : Karakterisering av elektriska egenskaper hos ett fuktmätnings system. (Thesis). Luleå University of Technology. Retrieved from http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-54848

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

Chicago Manual of Style (16^th Edition):

Karlsson, Christian A M. “Sensus Aquae in Ferrum ac Air : Karakterisering av elektriska egenskaper hos ett fuktmätnings system.” 2011. Thesis, Luleå University of Technology. Accessed January 16, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-54848.

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

MLA Handbook (7^th Edition):

Karlsson, Christian A M. “Sensus Aquae in Ferrum ac Air : Karakterisering av elektriska egenskaper hos ett fuktmätnings system.” 2011. Web. 16 Jan 2021.

Vancouver:

Karlsson CAM. Sensus Aquae in Ferrum ac Air : Karakterisering av elektriska egenskaper hos ett fuktmätnings system. [Internet] [Thesis]. Luleå University of Technology; 2011. [cited 2021 Jan 16]. Available from: http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-54848.

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

Council of Science Editors:

Karlsson CAM. Sensus Aquae in Ferrum ac Air : Karakterisering av elektriska egenskaper hos ett fuktmätnings system. [Thesis]. Luleå University of Technology; 2011. Available from: http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-54848

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

Indian Institute of Science

4. Chalasani, Rajesh. Functionalized Nanostructures : Iron Oxide Nanocrystals and Exfoliated Inorganic Nanosheets.

Degree: PhD, Faculty of Science, 2018, Indian Institute of Science

URL: http://etd.iisc.ac.in/handle/2005/3463

► This thesis consists of two parts. The first part deals with the magnetic properties of Fe3O4 nanocrystals and their possible application in water remediation. The… (more)

▼ This thesis consists of two parts. The first part deals with the magnetic properties of Fe3O4 nanocrystals and their possible application in water remediation. The second part is on the delamination of layered materials and the preparation of new layered hybrids from the delaminated sheets. In recent years, nanoscale magnetic particles have attracted considerable attention because of their potential applications in industry, medicine and environmental remediation. The most commonly studied magnetic nanoparticles are metals, bimetals and metal oxides. Of these, magnetite, Fe3O4, nanoparticles have been the most intensively investigated as they are, non-toxic, stable and easy to synthesize. Magnetic properties of nanoparticles such as the saturation magnetization, coercivity and blocking temperature are influenced both by size and shape. Below a critical size magnetic particles can become single domain and above a critical temperature (T B , the blocking temperature) thermal fluctuations can induce random flipping of magnetic moments resulting in loss of magnetic order. At temperatures above the blocking temperature the particles are superparamagnetic. Magnetic nanocrystals of similar dimensions but with different shapes show variation in magnetic properties especially in the value of the blocking temperature, because of differences in the surface anisotropy contribution. The properties of magnetic nanoparticles are briefly reviewed in Chapter 1. The objective of the present study was to synthesize Fe3O4 nanocrystals of different morphologies, to understand the difference in magnetic properties associated with shape and to explore the possibility of using Fe3O4 nanocrystals in water remediation. In the present study, oleate capped magnetite (Fe3O4) nanocrystals of spherical and cubic morphologies of comparable dimensions (∼10nm) have been synthesized by thermal decomposition of FeOOH in high-boiling octadecene solvent (Chapter 2). The nanocrystals were characterized by XRD, TEM and XPS spectroscopy. The nanoparticles of different morphologies exhibit very different blocking temperatures. Cubic nanocrystals have a higher blocking temperature (T B = 190 K) as compared to spheres (T B = 142 K). From the shift in the hysteresis loop it is demonstrated that the higher blocking temperature is a consequence of exchange bias or exchange anisotropy that manifests when a ferromagnetic material is in physical contact with an antiferromagnetic material. In nanoparticles, the presence of an exchange bias field leads to higher blocking temperatures T B because of the magnetic exchange coupling induced at the interface between the ferromagnet and antiferromagnet. It is shown that in these iron oxide nanocrystals the exchange bias field originates from trace amounts of the antiferromagnet wustite, FeO, present along with the ferrimagnetic Fe3O4 phase. It is also shown that the higher FeO content in nanocrystals of cubic morphology is responsible for the larger exchange bias fields that in turn lead to a higher blocking temperature.… Advisors/Committee Members: Vasudevan, S (advisor).

Subjects/Keywords: Nanostructures; Iron Oxide Nanocrystals; Exfoliated Inorgnaic Nanosheets; Iron Oxide Nanocrystals; Magnetic Nanocrystals; Magnetic Nanoparticles; Magnetic Iron Oxide Nanocrystals; Magnetic Nanoparticles; Surfactant Intercalation; Layered Materials - Delamination; [email protected]; Inorganic Nanosheets; Layered Double Hydroxide; Oleate Capped Magnetite Nanocrystals; Nanotechnology

Record Details Similar Records Cite « Share

❌

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

APA (6^th Edition):

Chalasani, R. (2018). Functionalized Nanostructures : Iron Oxide Nanocrystals and Exfoliated Inorganic Nanosheets. (Doctoral Dissertation). Indian Institute of Science. Retrieved from http://etd.iisc.ac.in/handle/2005/3463

Chicago Manual of Style (16^th Edition):

Chalasani, Rajesh. “Functionalized Nanostructures : Iron Oxide Nanocrystals and Exfoliated Inorganic Nanosheets.” 2018. Doctoral Dissertation, Indian Institute of Science. Accessed January 16, 2021. http://etd.iisc.ac.in/handle/2005/3463.

MLA Handbook (7^th Edition):

Chalasani, Rajesh. “Functionalized Nanostructures : Iron Oxide Nanocrystals and Exfoliated Inorganic Nanosheets.” 2018. Web. 16 Jan 2021.

Vancouver:

Chalasani R. Functionalized Nanostructures : Iron Oxide Nanocrystals and Exfoliated Inorganic Nanosheets. [Internet] [Doctoral dissertation]. Indian Institute of Science; 2018. [cited 2021 Jan 16]. Available from: http://etd.iisc.ac.in/handle/2005/3463.

Council of Science Editors:

Chalasani R. Functionalized Nanostructures : Iron Oxide Nanocrystals and Exfoliated Inorganic Nanosheets. [Doctoral Dissertation]. Indian Institute of Science; 2018. Available from: http://etd.iisc.ac.in/handle/2005/3463

		in
And / Or
		in
And / Or
		in
And / Or
		in

Open Access Theses and Dissertations