+publisher:"Georgia Tech" +contributor:("Lawrence Bottomley")

Georgia Tech

1. Costanza, Jed. Degradation of Tetrachloroethylene and Trichloroethylene under Thermal Remediation Conditions.

Degree: PhD, Civil and Environmental Engineering, 2005, Georgia Tech

► Thermal remediation involves heating subsurface environments and collecting fluids in order to recover contaminants such as tetrachloroethylene (PCE) and trichloroethylene (TCE). While increasing subsurface temperature… (more)

▼ Thermal remediation involves heating subsurface environments and collecting fluids in order to recover contaminants such as tetrachloroethylene (PCE) and trichloroethylene (TCE). While increasing subsurface temperature can lead to changes in the distribution of contaminants between the solid, liquid, and gas phases, there is also an increased potential for PCE and TCE to degrade. This work was performed to determine the rate of PCE and TCE degradation and products formed in laboratory-scale experiments designed to simulate thermal remediation conditions. The conditions during transport of gas-phase TCE were simulated using flow-through experiments in the temperature range from 60 to 800C. Degradation of TCE was not evident at temperatures of less than 240C; however, chloroacetic acids, which comprised less than 0.1% of the influent TCE on a carbon basis, were detected. At temperatures greater than 300C, TCE readily degraded where the identities of the degradation products were a function of oxygen and water content. With oxygen present, TCE degraded to form CO, phosgene, CO2 with minor amounts of hexachloroethane, PCE, and carbon tetrachloride. Increasing the amount of water vapor was found to decrease the amount of TCE degraded. Vapor recovery systems used during thermal treatments are anticipated to capture these TCE degradation products. However, the amount of missing carbon (~17%) in experiments completed at 800C makes the prospect of recovering all TCE degradation products doubtful. Experiments were conducted using hermetically sealed ampules to simulate heating dissolved phase PCE and TCE over periods of up to 75 days. At 120C, the first-order TCE degradation half-life was 330 days and the degradation products included CO and CO2, glycolate, formate, and chloride. The rate of TCE disappearance was increased with the addition of 1% (wt.) goethite, which suggests that the presence of iron bearing soil minerals can increase rates of TCE degradation during thermal treatment. In contaminated field samples, TCE was found to degrade to form cis-1,2-dichloroethylene at 95C coincident with the formation of hydrogen gas. Degradation of PCE was not evident in field samples or in deionized water and is not expected to degrade during thermal remediation at temperatures below 95C. Advisors/Committee Members: Pennell, Kurt (Committee Chair), carolyn ruppel (Committee Member), D. Webster (Committee Member), James Mulholland (Committee Member), Lawrence Bottomley (Committee Member).

Subjects/Keywords: Thermal; Trichloroethylene; Tetrachloroethylene; Degradation

Record Details Similar Records Cite « Share

❌

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

APA (6^th Edition):

Costanza, J. (2005). Degradation of Tetrachloroethylene and Trichloroethylene under Thermal Remediation Conditions. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/7485

Chicago Manual of Style (16^th Edition):

Costanza, Jed. “Degradation of Tetrachloroethylene and Trichloroethylene under Thermal Remediation Conditions.” 2005. Doctoral Dissertation, Georgia Tech. Accessed January 17, 2021. http://hdl.handle.net/1853/7485.

MLA Handbook (7^th Edition):

Costanza, Jed. “Degradation of Tetrachloroethylene and Trichloroethylene under Thermal Remediation Conditions.” 2005. Web. 17 Jan 2021.

Vancouver:

Costanza J. Degradation of Tetrachloroethylene and Trichloroethylene under Thermal Remediation Conditions. [Internet] [Doctoral dissertation]. Georgia Tech; 2005. [cited 2021 Jan 17]. Available from: http://hdl.handle.net/1853/7485.

Council of Science Editors:

Costanza J. Degradation of Tetrachloroethylene and Trichloroethylene under Thermal Remediation Conditions. [Doctoral Dissertation]. Georgia Tech; 2005. Available from: http://hdl.handle.net/1853/7485

Georgia Tech

2. Arredondo, Melissa Gayle. Zero-Dimensional Magnetite.

Degree: PhD, Chemistry and Biochemistry, 2006, Georgia Tech

URL: http://hdl.handle.net/1853/14151

► Low-dimensional magnetic systems are of interest due to several new effects and modifications that occur at sizes below the average domain grain boundary within the… (more)

▼ Low-dimensional magnetic systems are of interest due to several new effects and modifications that occur at sizes below the average domain grain boundary within the bulk material. Molecule-like magnetite (Fe3O4) nanoparticles, with sizes ranging from one to two nm were synthesized and characterized in order to investigate new properties arising from quantum size effects. These small systems will provide opportunities to investigate magnetism of zero-dimension systems. A zero-dimensional object is usually called a quantum dot or artificial atom because its electronic states are few and sharply separated in energy, resembling those within an atom. Since the surface to volume ratio is the highest for zero-dimensional systems, most of the changes to magnetic behavior will be observed in ultra-fine magnetic particles. Chemically functional magnetic nanoparticles, comprised of a Fe3O4 magnetite core encased in a thin aliphatic carboxylate, have been prepared by sequential high temperature decomposition of organometallic compounds in a coordinating solvent. In this work, aliphatic carboxylic acid chain length, reaction temperature and duration were varied to produce small core diameters. In order to correlate size effects with changes in particle formation, it is important to have a through understanding of the structural components. This includes studies of the core size, surface effects, decomposition, electronic properties and magnetic behavior. Quantum size effects were observed in the (Fe3O4)X(carboxylate)Y monolayer protected clusters (MPCs) when the average core diameter was ≤ 2.0 nm, evidenced by a blue shifted absorbance band maxima, suggesting the onset of quantum confinement. These (Fe3O4)X(carboxylate)Y MPCs also posses a complex interplay between surface and finite size effects, which govern the magnetic properties of these zero-dimensional systems. These MPCs are all superparamagnetic above their blocking temperatures with total magnetic anisotropy values greater than the bulk value due to an increase in surface and magnetocrystalline anisotropy. A non-linear decrease in saturation magnetization (MS) [Bohr Magneton] per cluster) as a function of the reciprocal of core radius have been attributed to surface effects such as a magnetically inactive layer or an increase in spin disorder as core diameter decreases. The reduced core dimensions of these MPCs make them ideal candidates for further investigation of quantum magnetic systems. Advisors/Committee Members: Robert Whetten (Committee Chair), Lawrence Bottomley, Walt De Heer, Mostafa El-Sayed, Uzi Landman, and David Sherrill (Committee Members).

Subjects/Keywords: Quantum magnetism; Quantum size effects; Magnetite; Nanoclusters; Nanoparticles; Superparamagnetism; Anisotropy; Magnetite; Nanoparticles; Paramagnetism; Quantum biochemistry; Surface chemistry

Record Details Similar Records Cite « Share

❌

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

APA (6^th Edition):

Arredondo, M. G. (2006). Zero-Dimensional Magnetite. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/14151

Chicago Manual of Style (16^th Edition):

Arredondo, Melissa Gayle. “Zero-Dimensional Magnetite.” 2006. Doctoral Dissertation, Georgia Tech. Accessed January 17, 2021. http://hdl.handle.net/1853/14151.

MLA Handbook (7^th Edition):

Arredondo, Melissa Gayle. “Zero-Dimensional Magnetite.” 2006. Web. 17 Jan 2021.

Vancouver:

Arredondo MG. Zero-Dimensional Magnetite. [Internet] [Doctoral dissertation]. Georgia Tech; 2006. [cited 2021 Jan 17]. Available from: http://hdl.handle.net/1853/14151.

Council of Science Editors:

Arredondo MG. Zero-Dimensional Magnetite. [Doctoral Dissertation]. Georgia Tech; 2006. Available from: http://hdl.handle.net/1853/14151

Georgia Tech

3. Steeb, Jennifer L. Nickel-63 microirradiators and applications.

Degree: PhD, Chemistry and Biochemistry, 2010, Georgia Tech

URL: http://hdl.handle.net/1853/34773

► In this thesis, manufacturing of microirradiators, electrodeposition of radioactive elements such as Ni-63, and applications of these radioactive sources are discussed. Ni-63 has a half… (more)

▼ In this thesis, manufacturing of microirradiators, electrodeposition of radioactive elements such as Ni-63, and applications of these radioactive sources are discussed. Ni-63 has a half life of 100 years and a low energy beta electron of 67 keV, ideal for low dose low linear energy transfer (LET) research. The main focus of the research is on the novel Ni-63 microirradiator. It contains a small amount of total activity of radiation but a large flux, allowing the user to safely handle the microirradiator without extensive shielding. This thesis is divided into nine chapters. Properties of microirradiators and various competing radioactive sources are compared in the introduction (chapter 1). Detailed description of manufacturing Ni-63 microirradiator using the microelectrode as the starting point is outlined in chapter 2. The microelectrode is a 25 µm in diameter Pt disk sealed in a pulled 1 mm diameter borosilicate capillary tube, as a protruding wire or recessed disk microelectrode. The electrochemically active surface area of each is verified by cyclic voltammetry. Electrodeposition of nickel with a detailed description of formulation of the electrochemical bath in a cold "non-radioactive setting" was optimized by using parameters as defined by pourbaix diagrams, radioactive electroplating of Ni-63, and incorporation of safety regulations into electrodeposition. Calibration and characterization of the Ni-63 microirradiators as protruding wire and recessed disk microirradiators is presented in chapter 3. In chapters 4 through 6, applications of the Ni-63 microirradiators and wire sources are presented. Chapter 4 provides a radiobiological application of the recessed disk microirradiator and a modified flush microirradiator with osteosarcoma cancer cells. Cells were irradiated with 2000 to 1 Bq, and real time observations of DNA double strand breaks were observed. A novel benchtop detection system for the microirradiators is presented in chapter 5. Ni-63 is most commonly measured by liquid scintillation counters, which are expensive and not easily accessible within a benchtop setting. Results show liquid scintillation measurements overestimates the amount of radiation coming from the recessed disk. A novel 10 µCi Ni-63 electrochemically deposited wire acting as an ambient chemical ionization source for pharmaceutical tablets in mass spectrometry is in chapter 6. Typically, larger radioactive sources (15 mCi) of Ni-63 have been used in an ambient ionization scenario. Additionally, this is the first application of using Ni-63 to ionize in atmosphere pharmaceutical tablets, leading to a possible field portable device. In the last chapters, chapters 7 through 8, previous microirradiator experiments and future work are summarized. Chapter 7 illustrates the prototype of the electrochemically deposited microirradiator, the Te-125 microirradiator. In conjunction with Oak Ridge National Laboratory, Te-125m is a low dose x-ray emitting element determined to be the best first prototype of an electrochemically deposited… Advisors/Committee Members: Jiri Janata (Committee Chair), Chris Wang (Committee Member), Facundo Fernandez (Committee Member), Lawrence Bottomley (Committee Member), Mira Josowicz (Committee Member).

Subjects/Keywords: Electrodeposition; Nickel-63; Microirradiator; Radiobiology; Radiation delivery; Radioisotope; Electroplating; Nickel-plating; Plating baths; Liquid scintillation counting

Record Details Similar Records Cite « Share

❌

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

APA (6^th Edition):

Steeb, J. L. (2010). Nickel-63 microirradiators and applications. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/34773

Chicago Manual of Style (16^th Edition):

Steeb, Jennifer L. “Nickel-63 microirradiators and applications.” 2010. Doctoral Dissertation, Georgia Tech. Accessed January 17, 2021. http://hdl.handle.net/1853/34773.

MLA Handbook (7^th Edition):

Steeb, Jennifer L. “Nickel-63 microirradiators and applications.” 2010. Web. 17 Jan 2021.

Vancouver:

Steeb JL. Nickel-63 microirradiators and applications. [Internet] [Doctoral dissertation]. Georgia Tech; 2010. [cited 2021 Jan 17]. Available from: http://hdl.handle.net/1853/34773.

Council of Science Editors:

Steeb JL. Nickel-63 microirradiators and applications. [Doctoral Dissertation]. Georgia Tech; 2010. Available from: http://hdl.handle.net/1853/34773

Georgia Tech

4. Brotherson, Brett Andrew. Site blocking effects on adsorbed polyacrylamide conformation.

Degree: PhD, Chemical Engineering, 2007, Georgia Tech

URL: http://hdl.handle.net/1853/26509

► The use of polymers as flocculating additives is a common practice in many manufacturing environments. However, exactly how these polymers interact with surfaces is relatively… (more)

▼ The use of polymers as flocculating additives is a common practice in many manufacturing environments. However, exactly how these polymers interact with surfaces is relatively unknown. One specific topic which is thought to be very important to flocculation is an adsorbed polymer's conformation. Substantial amounts of previous work, mainly using simulations, have been performed to elucidate the theory surrounding adsorbed polymer conformations. Yet, there is little experimental work which directly verifies current theory. In order to optimize the use of polymer flocculants in industrial applications, a better understanding of an adsorbed polymer's conformation on a surface beyond theoretical simulations is necessary. This work looks specifically at site blocking, which has a broad impact on flocculation, adsorption, and surface modification, and investigated its effects on the resulting adsorbed polymer conformation. Experimental methods which would allow direct determination of adsorbed polymer conformational details and be comparable with previous experimental results were first determined or developed. Characterization of an adsorbed polymer's conformation was then evaluated using dynamic light scattering, a currently accepted experimental technique to examine this. This commonly used technique was performed to allow the comparison of this works results with past literature. Next, a new technique using atomic force microscopy was developed, building on previous experimental techniques, to allow the direct determination of an adsorbed polymer's loop lengths. This method also was able to quantify changes in the length of adsorbed polymer tails. Finally, mesoscopic simulation was attempted using dissipative particle dynamics. In order to determine more information about an adsorbed polymer's conformation, three different environmental factors were analyzed: an adsorbed polymer on a surface in water, an adsorbed polymer on a surface in aqueous solutions of varying ionic strength, and an adsorbed polymer on a surface functionalized with site blocking additives. This work investigated these scenarios using a low charge density high molecular weight cationic polyacrylamide. Three different substrates, for polymer adsorption were analyzed: mica, anionic latex, and glass. It was determined that, similar to previous studies, the adsorbed polymer layer thickness in water is relatively small even for high molecular weight polymers, on the order of tens of nanometers. The loop length distribution of a single polymer, experimentally verified for the first time, revealed a broad span of loop lengths as high as 1.5 microns. However, the bulk of the distribution was found between 40 and 260 nanometers. For the first time, previous theoretical predictions regarding the salt effect on adsorbed polymer conformation were confirmed experimentally. It was determined that the adsorbed polymer layer thickness expanded with increasing ionic strength of the solvent. Using atomic force microscopy, it was… Advisors/Committee Members: Yulin Deng (Committee Chair), Peter Ludovice (Committee Co-Chair), James Frederick (Committee Member), Lawrence Bottomley (Committee Member), Preet Singh (Committee Member).

Subjects/Keywords: Scanning probe microscopy; Atomic force microscopy; Tail length; Loop length; Adsorbed polymer conformation; Salt effect; Site blocking effect; Polyacrylamide; Flocculation; Adsorption

Record Details Similar Records Cite « Share

❌

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

APA (6^th Edition):

Brotherson, B. A. (2007). Site blocking effects on adsorbed polyacrylamide conformation. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/26509

Chicago Manual of Style (16^th Edition):

Brotherson, Brett Andrew. “Site blocking effects on adsorbed polyacrylamide conformation.” 2007. Doctoral Dissertation, Georgia Tech. Accessed January 17, 2021. http://hdl.handle.net/1853/26509.

MLA Handbook (7^th Edition):

Brotherson, Brett Andrew. “Site blocking effects on adsorbed polyacrylamide conformation.” 2007. Web. 17 Jan 2021.

Vancouver:

Brotherson BA. Site blocking effects on adsorbed polyacrylamide conformation. [Internet] [Doctoral dissertation]. Georgia Tech; 2007. [cited 2021 Jan 17]. Available from: http://hdl.handle.net/1853/26509.

Council of Science Editors:

Brotherson BA. Site blocking effects on adsorbed polyacrylamide conformation. [Doctoral Dissertation]. Georgia Tech; 2007. Available from: http://hdl.handle.net/1853/26509

Georgia Tech

5. Marotta, Nicole Ella. Patterned nanoarray sers substrates for pathogen detection.

Degree: PhD, Chemistry and Biochemistry, 2010, Georgia Tech

URL: http://hdl.handle.net/1853/37274

► The objectives of the work presented were to 1) fabricate reproducible nanorod array SERS substrates, 2) detection of bacteria using nanorod substrates, 3) detection of… (more)

▼ The objectives of the work presented were to 1) fabricate reproducible nanorod array SERS substrates, 2) detection of bacteria using nanorod substrates, 3) detection of DNA hybridization using nanorod substrates and 4) critically evaluate the sensing method. Important findings from this work are as follows. A novel method for batch fabrication of substrates for surface enhanced Raman scattering (SERS) has been developed using a modified platen machined to fit in a commercial electron beam evaporator. The use of this holder enables simultaneous deposition of silver nanorod (AgNR) arrays onto six microscope slide substrates utilizing glancing angle deposition. In addition to multiple substrate fabrication, patterning of the AgNR substrates with 36 wells allows for physical isolation of low volume samples. The well-to-well, slide-to-slide, and batch-to-batch variability in both physical characteristics and SERS response of substrates prepared via this method was nominal. A critical issue in the continued development of AgNR substrates is their stability over time, and the potential impact on the SERS response. The thermal stability of the arrays was investigated and changes in surface morphology were evaluated using scanning electron microscopy and x-ray diffraction and correlated with changes in SERS enhancement. The findings suggest that the shelf-life of AgNR arrays is limited by migration of silver on the surface. Continued characterization of the AgNR arrays was carried out using fluorescent polystyrene microspheres of two different sizes. Theory suggests that enhancement between nanorods would be significantly greater than at the tops due to contributing electromagnetic fields from each nanostructure. In contrast to the theory, SERS response of microspheres confined to the tops of the AgNR array was significantly greater than that for beads located within the array. The location of the microspheres was established using optical fluorescence and scanning electron microscopy. The application of SERS to characterizing pathogens such as bacteria and viruses is an active area of investigation. AgNR array-based SERS substrates have enabled detection of pathogens present in biofluids. Specifically, several publications have focused on determining the spectral bands characteristic of bacteria from different species and cell lines. Studies were carried out on three strains of bacteria as well as the medium in which the bacteria were grown. The spectra of the bacteria and medium were surprisingly similar, so additional spectra were acquired for commonly used bacterial growth media. In many instances, these spectra were similar to published spectra purportedly characteristic of specific bacterial species. In addition to bacterial samples, nucleic acid hybridization assays were investigated. Oligonucleotide pairs specifically designed to detect respiratory syncytial virus (RSV) in nasal fluids were prepared and evaluated. SERS spectra acquired on oligos, alone or in combination, contain the… Advisors/Committee Members: Lawrence Bottomley (Committee Chair), Julia Kubanek (Committee Member), L. Andrew Lyon (Committee Member), Loren Williams (Committee Member), Mostafa El-Sayed (Committee Member).

Subjects/Keywords: Silver nanostructure; Surface enhanced Raman scattering; Silver nanorod array; Surface enhanced Raman spectroscopy; Oblique angle deposition; Glancing angle deposition; SERS substrate; Raman effect; Raman spectroscopy

Record Details Similar Records Cite « Share

❌

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

APA (6^th Edition):

Marotta, N. E. (2010). Patterned nanoarray sers substrates for pathogen detection. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/37274

Chicago Manual of Style (16^th Edition):

Marotta, Nicole Ella. “Patterned nanoarray sers substrates for pathogen detection.” 2010. Doctoral Dissertation, Georgia Tech. Accessed January 17, 2021. http://hdl.handle.net/1853/37274.

MLA Handbook (7^th Edition):

Marotta, Nicole Ella. “Patterned nanoarray sers substrates for pathogen detection.” 2010. Web. 17 Jan 2021.

Vancouver:

Marotta NE. Patterned nanoarray sers substrates for pathogen detection. [Internet] [Doctoral dissertation]. Georgia Tech; 2010. [cited 2021 Jan 17]. Available from: http://hdl.handle.net/1853/37274.

Council of Science Editors:

Marotta NE. Patterned nanoarray sers substrates for pathogen detection. [Doctoral Dissertation]. Georgia Tech; 2010. Available from: http://hdl.handle.net/1853/37274

Georgia Tech

6. Thomson, Cameron Ian. Probing the Nature of Cellulosic Fibre Interfaces with Fluorescence Resonance Energy Transfer.

Degree: PhD, Chemistry and Biochemistry, 2007, Georgia Tech

URL: http://hdl.handle.net/1853/16277

► The material properties of fibre networks and fibre reinforced composites are strongly influenced by fibre-fibre interactions. Stress transfer between load bearing elements in such materials… (more)

▼ The material properties of fibre networks and fibre reinforced composites are strongly influenced by fibre-fibre interactions. Stress transfer between load bearing elements in such materials is often dictated by the nature of the fibre-fibre interface. Inter-fibre bonding is solely responsible for internal cohesion in paper, because all stresses transferred between fibres operate through fibre-fibre bonds. . The future development of cellulosic fibre materials will require an improved understanding of the fibre-fibre interface. Fluorescence resonance energy transfer (FRET) was proposed as a new tool for the study of fibre interfaces. A protocol for covalent linkage of fluorophores to natural and regenerated cellulosic fibres was developed and the absorptive and emissive properties of these dyes were characterized. The fluorescent response of these dyed fibres in paper sheets was studied using steady-state fluorescence spectroscopy. Fluorescence micrographs of fibre crossings on glass slides were analyzed using the FRETN correction algorithm. Energy transfer from coumarin dyed fibres to fluorescein dyed fibres at the interface was observed. The FRETN surfaces for spruce and viscose rayon fibre crossings were distinctly different. The FRET microscopy method was able to detect statistically significant differences in spruce fibre interface development when fibre fraction and wet pressing were varied. The coalescence of natural cellulosic fibre interfaces during drying was also observed with the technique. Polysaccharide films were employed as model systems for the natural and regenerated cellulose fibre interfaces. It was found that pressing cellulose films did not result in significantly increased FRETN either due to resistance to deformation or the inability to participate in interdiffusion. Conversely, xylan films demonstrated a drastic increase in the FRETN signal with increased wet pressing. These results support the previously observed differences between regenerated cellulose fibres and natural wood fibres. The results of the FRETN analysis of the polysaccharide film model systems suggest that lower molecular weight amorphous carbohydrates are likely to be significant contributors to fibre interface development. Advisors/Committee Members: Arthur J. Ragauskas (Committee Chair), Andrew Lyon (Committee Member), Lawrence Bottomley (Committee Member), Timothy Patterson (Committee Member), Yulin Deng (Committee Member).

Subjects/Keywords: Fiber bonding; FRET; Fluorescence microscopy; Fibers; Cellulose; Fibers Mechanical properties; Fibrous composites; Cellulose fibers Testing

Record Details Similar Records Cite « Share

❌

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

APA (6^th Edition):

Thomson, C. I. (2007). Probing the Nature of Cellulosic Fibre Interfaces with Fluorescence Resonance Energy Transfer. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/16277

Chicago Manual of Style (16^th Edition):

Thomson, Cameron Ian. “Probing the Nature of Cellulosic Fibre Interfaces with Fluorescence Resonance Energy Transfer.” 2007. Doctoral Dissertation, Georgia Tech. Accessed January 17, 2021. http://hdl.handle.net/1853/16277.

MLA Handbook (7^th Edition):

Thomson, Cameron Ian. “Probing the Nature of Cellulosic Fibre Interfaces with Fluorescence Resonance Energy Transfer.” 2007. Web. 17 Jan 2021.

Vancouver:

Thomson CI. Probing the Nature of Cellulosic Fibre Interfaces with Fluorescence Resonance Energy Transfer. [Internet] [Doctoral dissertation]. Georgia Tech; 2007. [cited 2021 Jan 17]. Available from: http://hdl.handle.net/1853/16277.

Council of Science Editors:

Thomson CI. Probing the Nature of Cellulosic Fibre Interfaces with Fluorescence Resonance Energy Transfer. [Doctoral Dissertation]. Georgia Tech; 2007. Available from: http://hdl.handle.net/1853/16277

Georgia Tech

7. Penescu, Mihaela. Diffusion of cyclic versus linear poly(oxyethylene) oligomers in poly(methyl methacrylate) by ATR-FTIR spectroscopy.

Degree: PhD, Chemistry and Biochemistry, 2009, Georgia Tech

URL: http://hdl.handle.net/1853/29740

► Diffusion of linear and cyclic poly(oxyethylene) (POE) oligomers in poly(methyl methacrylate) (PMMA) matrix was investigated in situ using attenuated total reflectance (ATR) infrared (IR) spectroscopy… (more)

Subjects/Keywords: Case II; Fickian; Matrix relaxation; Mutual diffusion; Diffusion; Oligomers Confomation; Molecular structure; Infrared spectroscopy

Record Details Similar Records Cite « Share

❌

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

APA (6^th Edition):

Penescu, M. (2009). Diffusion of cyclic versus linear poly(oxyethylene) oligomers in poly(methyl methacrylate) by ATR-FTIR spectroscopy. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/29740

Chicago Manual of Style (16^th Edition):

Penescu, Mihaela. “Diffusion of cyclic versus linear poly(oxyethylene) oligomers in poly(methyl methacrylate) by ATR-FTIR spectroscopy.” 2009. Doctoral Dissertation, Georgia Tech. Accessed January 17, 2021. http://hdl.handle.net/1853/29740.

MLA Handbook (7^th Edition):

Penescu, Mihaela. “Diffusion of cyclic versus linear poly(oxyethylene) oligomers in poly(methyl methacrylate) by ATR-FTIR spectroscopy.” 2009. Web. 17 Jan 2021.

Vancouver:

Penescu M. Diffusion of cyclic versus linear poly(oxyethylene) oligomers in poly(methyl methacrylate) by ATR-FTIR spectroscopy. [Internet] [Doctoral dissertation]. Georgia Tech; 2009. [cited 2021 Jan 17]. Available from: http://hdl.handle.net/1853/29740.

Council of Science Editors:

Penescu M. Diffusion of cyclic versus linear poly(oxyethylene) oligomers in poly(methyl methacrylate) by ATR-FTIR spectroscopy. [Doctoral Dissertation]. Georgia Tech; 2009. Available from: http://hdl.handle.net/1853/29740

Georgia Tech

8. Thio, Beng Joo Reginald. Characterization of bioparticulate adhesion to synthetic carpet polymers with atomic force microscopy.

Degree: PhD, Chemical Engineering, 2008, Georgia Tech

URL: http://hdl.handle.net/1853/31727

► Particles originating from bacteria, fungi (including mold spores, mildew, yeast), pollen, dust mites, and viruses can induce immune responses that trigger allergies and asthma. Carpeting… (more)

▼ Particles originating from bacteria, fungi (including mold spores, mildew, yeast), pollen, dust mites, and viruses can induce immune responses that trigger allergies and asthma. Carpeting is believed to act as a "sink" where bioparticulates are trapped via adhesive interactions and then are released by foot traffic or cleaning. This scenario can result in an accumulation of contaminants at higher levels than would be found outdoors or in a carpet-less environment. Numerous organizations (school districts, hospitals) have taken steps to remove carpeting, even though this hypothesis remains unproven. While statistical studies exist both in support and denial of the accumulation hypothesis, there is little fundamental understanding of the microscopic-level interactions between carpet and bioparticles. A fundamental understanding of particle affinities with polymers utilized in carpet would help to develop accurate models and address real problems in a rational and productive manner. In addition, a solution to the bioparticulate accumulation problem would have a profound impact on US health, resulting in significant economic savings. More than 20 million people suffer from asthma in the U.S., with children being the most vulnerable. In 2000 there were 9.3 million physician office visits and 1.8 million emergency room visits due to asthma alone, resulting in an estimated 9.4 billion in medical costs and 4.6 billion in lost productivity annually. In this thesis, two measurement techniques were developed to quantify the adhesive interactions between biological particulates and polymeric carpeting materials. Atomic force microscopy (AFM) was used to measure the adhesive interactions of relevant biological particulates (in this case the E. coli bacteria and A. artemisiifolia ragweed pollen grains) with Nylon-6 and Nylon-6,6, polyamide-12 and polystyrene. The adhesion force measurements were modeled using several adhesion theories. We found that the Hamaker models were sufficient for explaining the data, indicating the prominence of van der Waals forces in controlling bioparticle interactions with polyamides. In addition, the geometry of the pollen played a significant role: adhesion forces were approximately a multiple of the number of contact points the grain has with the surface. Forces for E. coli and polyamides were about the same magnitude as polyamide-polyamide surface self-interactions. Advisors/Committee Members: J. Carson Meredith (Committee Chair), Amyn Teja (Committee Member), F. Joseph Schork (Committee Member), Lawrence Bottomley (Committee Member), Mark Prausnitz (Committee Member).

Subjects/Keywords: E. coli; AFM; Adhesion; Van der Waals; Polyamide; Pollen; Nylon; Hamaker constants; Polystyrene; Intermolecular force; Carpets; Polymers; Textile fibers, Synthetic; Atomic force microscopy; Polyamides

Record Details Similar Records Cite « Share

❌

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

APA (6^th Edition):

Thio, B. J. R. (2008). Characterization of bioparticulate adhesion to synthetic carpet polymers with atomic force microscopy. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/31727

Chicago Manual of Style (16^th Edition):

Thio, Beng Joo Reginald. “Characterization of bioparticulate adhesion to synthetic carpet polymers with atomic force microscopy.” 2008. Doctoral Dissertation, Georgia Tech. Accessed January 17, 2021. http://hdl.handle.net/1853/31727.

MLA Handbook (7^th Edition):

Thio, Beng Joo Reginald. “Characterization of bioparticulate adhesion to synthetic carpet polymers with atomic force microscopy.” 2008. Web. 17 Jan 2021.

Vancouver:

Thio BJR. Characterization of bioparticulate adhesion to synthetic carpet polymers with atomic force microscopy. [Internet] [Doctoral dissertation]. Georgia Tech; 2008. [cited 2021 Jan 17]. Available from: http://hdl.handle.net/1853/31727.

Council of Science Editors:

Thio BJR. Characterization of bioparticulate adhesion to synthetic carpet polymers with atomic force microscopy. [Doctoral Dissertation]. Georgia Tech; 2008. Available from: http://hdl.handle.net/1853/31727

Georgia Tech

9. Barber, Jabulani Randall Timothy. Mechanical compression of coiled carbon nanotubes.

Degree: PhD, Chemistry and Biochemistry, 2009, Georgia Tech

URL: http://hdl.handle.net/1853/28216

► Carbon nanotubes are molecular-scale tubes of graphitic carbon that possess many unique properties. They have high tensile strength and elastic modulus, are thermally and electrically… (more)

▼ Carbon nanotubes are molecular-scale tubes of graphitic carbon that possess many unique properties. They have high tensile strength and elastic modulus, are thermally and electrically conductive, and can be structurally modified using well established carbon chemistries. There is global interest in taking advantage of their unique combination of properties and using these interesting materials as components in nanoscale devices and composite materials. The goal of this research was the correlation of the mechanical properties of coiled carbon nanotubes with their chemical structure. Individual nanocoils, grown by chemical vapor deposition, were attached to scanning probe tip using the arc discharge method. Using a scanning probe microscope the nanocoils are repeatedly brought into and out of contact with a chemically-modified substrate. Precise control over the length (or area) of contact with the substrate is achievable through simultaneous monitoring the cantilever deflection resonance, and correlating these with scanner movement. The mechanical response of nanocoils depended upon the extent of their compression. Nonlinear response of the nanocoil was observed consistent with compression, buckling, and slip-stick motion of the nanocoil. The chemical structure of the nanocoil and its orientation on the tip was determined using scanning and transmission electron microscopy. The mechanical stiffness of eighteen different nanocoils was determined in three ways. In the first, the spring constant of each nanocoil was computed from the slope of the linear response region of the force-distance curve. The assumptions upon which this calculation is based are: 1) under compression, the cantilever-nanocoil system can be modeled as two-springs in series, and 2) the nanocoil behaves as an ideal spring as the load from the cantilever is applied. Nanocoil spring constants determined in this fashion ranged from 6.5x10-3 to 5.16 TPa for the CCNTs understudy. In the second, the spring constant of the nanocoil was computed from measuring the critical force required to buckle the nanocoil. The critical force method measured the force at the point where the nanocoil-cantilever system diverges from a linear region in the force curve. Nanocoil spring constants determined in this fashion ranged from 1.3x10-5 to 10.4 TPa for the CCNTs understudy. In the third, the spring constant of each nanocoil was computed from the thermal resonance of the cantilever-nanocoil system. Prior to contact of the nanocoil with the substrate, the effective spring constant of the system is essentially that of the cantilever. At the point of contact and prior to buckling or slip-stick motion, the effective spring constant of the system is modeled as two springs in parallel. Nanocoil spring constants determined in this fashion ranged from 2.7x10-3 to 0.03 TPa for the CCNTs understudy. Using the thermal resonance of the cantilever system a trend was observed relating nanocoil structure to the calculated modulus. Hollow, tube-like… Advisors/Committee Members: Lawrence Bottomley (Committee Chair), Aldo Ferri (Committee Member), E. Kent Barefield (Committee Member), Levent Degertekin (Committee Member), Robert Whetten (Committee Member), Satish Kumar (Committee Member), Zhong Lin Wang (Committee Member).

Subjects/Keywords: Slip-stick; Tribology; Thermal resonance spectrum; Mechanical properties; Force spectroscopy; Atomic force microscopy; Nanocoil; Multi-walled carbon nanotube; Nanospring; Nanotube; Nanotubes Mechanical properties; Carbon; Chemical structure; Springs (Mechanism)

Record Details Similar Records Cite « Share

❌

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

APA (6^th Edition):

Barber, J. R. T. (2009). Mechanical compression of coiled carbon nanotubes. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/28216

Chicago Manual of Style (16^th Edition):

Barber, Jabulani Randall Timothy. “Mechanical compression of coiled carbon nanotubes.” 2009. Doctoral Dissertation, Georgia Tech. Accessed January 17, 2021. http://hdl.handle.net/1853/28216.

MLA Handbook (7^th Edition):

Barber, Jabulani Randall Timothy. “Mechanical compression of coiled carbon nanotubes.” 2009. Web. 17 Jan 2021.

Vancouver:

Barber JRT. Mechanical compression of coiled carbon nanotubes. [Internet] [Doctoral dissertation]. Georgia Tech; 2009. [cited 2021 Jan 17]. Available from: http://hdl.handle.net/1853/28216.

Council of Science Editors:

Barber JRT. Mechanical compression of coiled carbon nanotubes. [Doctoral Dissertation]. Georgia Tech; 2009. Available from: http://hdl.handle.net/1853/28216

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

Open Access Theses and Dissertations