Physical Sciences and Mathematics Commons^™

Nanomaterial Composites For The Detection Of Nerve Gas Analogs, Yogesh Datar

Masters Theses

The basis of the research work described here is the use of nanocomposite materials built by bottom-up approach for the selective detection of nerve gas analogs. Nanocomposites materials constructed by using nanoparticle-monomer-receptor (NMR) concept have been utilized to detect nerve gas analogs DCP and DMMP. Synthetic approach used in the construction of nanosensors involved use of robust platforms such as silica nanoparticles and fluorescent quantum dots. Highly conjugated receptor molecules were synthesized by using stilbeneoid compounds. A complete opto-nanosensor was developed by anchoring highly conjugated receptor molecules onto the silica nanoparticles as well as onto the quantum dots. The opto-nanosensors …

What Allows Teachers To Extend Student Thinking During Whole-Group Discussions, Nesrin Cengiz

Dissertations

Research indicates that extending students' mathematical thinking during whole-group discussions is challenging, even for the most experienced teachers. That is, it is challenging for teachers to help students move beyond their initial mathematical observations and solutions during whole-group discussions. To better understand this phenomena, the teaching of six experienced elementary school teachers, who had been teaching aStandards-based curriculum for several years and had participated in a multi-year professional development project focused on that curriculum, is explored in this study. In particular, two issues are addressed: what it looks like to extend student thinking during whole-group discussions and how …

Structure And Excitations In Metal Ammonia Compounds, Xue Wang

Dissertations

This work has two parts. In the first part, inelastic x-ray scattering was used to measure the plasmon excitations in liquid lithium ammonia systems. The measurements were carried out for different metal concentrations, 8 mole per metal (MPM), 10 MPM, 11 MPM, 16 MPM and 20 MPM of temperature 200K. The data were analyzed to determine the plasmon energy and the linewidth as a function of momentum for each metal concentration. Deviations from the random phase approximation (RPA) in the jellium model increase as the concentration is lowered.

In the second part of this work, elastic x-ray scattering was used …

Adsorption Of Lead On Single And Mixed Solid Systems, Soumya Das

Dissertations

Metal oxy-hydroxides and phyllosilicate minerals play a significant role in the fate and transport of heavy metals in the environment (Bertsch and Seaman, 1999). Chemical speciation of metals affects their bioavailability and chemical reactivity (Stumm and Morgan, 1996). Surface complexation models (SCMs) based on equilibrium thermodynamic principles have been successfully used to quantify adsorption of heavy metals on pure solid minerals, including phyllosilicates and oxy-hydroxides. For natural sediments with mixed mineralogy, Davis et al. (1998) suggested two different SCM approaches, namely, the component additivity and generalized composite models. In this study, adsorption of lead on pure HFO, silica and kaolinite …

Quantum Properties Of Light Emitted By Dipole Nano-Laser, Talal Ghannam

Dissertations

Recent technological advances allow entire optical systems to be lithographically implanted on small silicon chips. These systems include tiny semiconductor lasers that function as light sources for digital optical signals. Future advances will rely on even smaller components. At the theoretical limit of this process, the smallest lasers will have an active medium consisting of a single atom (natural or artificial). Several suggestions for how this can be accomplished have already been published, such as nano-lasers based on photonic crystals and nano wires. In particular, the "dipole nanolaser" consists of a single quantum dot functioning as the active medium. It …

Synthesis, Study Of Self-Assembly, And Trivalent Lanthanide Metal Ion Recognition Characteristics Of Amphiphilic Acylpyrazolones And Amphiphilic Acylisoxazolones, Venkat Reddy Guduru

Dissertations

This research project focused on the separation of trivalent lanthanide metal ions by HPLC using amphiphilic acylpyrazolones and amphiphilic acylisoxazolones. The central hypothesis of our research project is that the nanoscale self-assembly nature of amphiphilic ligands (chelating lingads) can influence their metal ion recognition and separation. To test the central hypothesis, we have synthesized a family of novel amphiphilic ligands and employed them as model systems for the separation of trivalent lanthanide metal ions. Several novel intermediates such as 4-acylated. N -acylated, O -acylated pyrazolones and isoxazolones, have been efficiently synthesized and fully characterized.*

The trivalent lanthanide metal ion recognition …

Diagnostics For Choosing Between Log-Rank And Wilcoxon Tests, Ruvie Lou Maria Custodio Martinez

Dissertations

Two commonly used tests for comparison of survival curves are the generalized Wilcoxon procedure of Gehan (1965) and Breslow (1970) and the Log-rank test proposed by Mantel (1966) and Cox (1972). In applications, the Log-rank test is used after checking for validity of the proportional hazards (PH) assumption, with Wilcoxon being the fallback method when the PH assumption fails.

However, the relative performance of the two procedures depend not just on the PH assumption but also on the pattern of differences between the two curves. We will show that the crucial factor is whether the differences tend to occur early …

Synthesis And Characterization Of Ruthenium Bipyridyl Complexes For Detecting Nerve Gas Agents And Explosives, Arambe Gedara Aruna Weerasinghe

Masters Theses

Five novel 2,2 '-bis bi pyridine Ru(II) complexes have been synthesized and characterized using ¹H NMR, ¹³C NMR, ¹H-¹H-COSY, elemental analysis, fast atom bombardment or electrospray mass spectra and electronic absorption spectroscopy. Binding of Ru (11) complexes with nerve gas analogos such as diethyl chlorophosphate (DCP), dimethyl methyl phosphonate (DMMP) and hydrolyzed product (HCl) has been investigated by electronic absorption, fluorescence, and lifetime studies. Compound 1 showed a quenching in ³MLCT emission after an initial increase in intensity upon the addition of DCP with a bathochromic shift of 25 nm. Compound 2 exhibit a …

Design Of Multi-Electron Transfer Catalysts For The Reduction Of Trichloroethylene, Christopher Gerard Eman Ciptadjaya

Masters Theses

For decades, organohalide (RX) compounds have been heavily used in the chemical and pharmaceutical industries and in agriculture as pesticides. Improper disposal of organohalides has resulted in their presence in the environment as pollutants, and they have therefore presented serious environmental and toxicological concerns. These organohalides have been associated with various health and environmental problems. Therefore, effective methods for their remediation are required. We have developed a multi-electron transfer (MET) catalyst consisting of flavin mononucleotide anchored to nanocrystalline mesoporous titanium dioxide (TiO₂) thin films, and examined its reactivity toward the organohalide pollutant trichloroethylene (TCE). Various environmental factors were …

Extensions Of Two-Part Tests To Compare K Independent Populations, Marwan Daoud

Dissertations

We consider two-part models that are mixtures of a point-mass variable with all mass at zero and a continuous random variable. The model may assume a particular distributionh(x) for the continuous part such as a log-normal or a gamma. The response variable is defined as y=(x, d), where d=1 if x > 0 and d=0 if x = 0. The probability distribution function has the following form: fx,d=p ^1-d×1-p ×hx ^d.

Lachenbruch (1976, 2001) proposed several tests to compare means of two populations for this type of data. We proposed a two-part Wald test and …

Synthesis And Characterization Of Stilbenoids And Their Aza-Analogs As Photoluminescent Materials For The Detection Of Nerve Agent Mimics, Chun Wang

Dissertations

A novel series of stilbenoids and their aza analogs were synthesized, characterized and used as photoluminescent components in the detection of nerve agents. Their structure-property relationship was elucidated through UV-visible and fluorescence spectroscopy. The research in this thesis is driven by the hypothesis that the two-block sensor system consisting of a receptor incorporated ruthenium complex and a fluorescent signal molecule of stilbenoids, is capable of detecting chemical warfare agents. The sensor anchored onto nanoparticles and subsequently the nanoparticles were arranged through mediated self-assembly. While photo-induced electron transfer is a well-known mechanism for sensor design, the described system showed that photo-induced …

Nanosensors For The Detection Of Nerve Agents And Explosives, Deepak Kumar Thimmaraju

Masters Theses

The central hypothesis of this research was development of a novel nanosensor for the detection of nerve agents and explosives. The nanosensor assembly comprises a bottom up approach with nanoparticle (N), monomer (M), nanomolecule (N) and a receptor (R) as moieties of a NMNR assembly. My research was focused on evaluating receptors for their efficiency towards the target analytes such as nerve agents and explosives. Pi electron rich receptor 2-Phenyl-2-Propanol and its fluorinated analog 1,1,1,3,3,3-Hexafluoro-2-Phenyl-2-Propanol were investigated for their ability to detect nerve agents such as DCP, its analogs DMMP and HCl along with the explosives mono, di, and trinitrotoluene. …

The Effect Of A Skyrme Interaction On Nucleon Induced Reactions, Yingfa Zhang

Masters Theses

The main goal of this Master thesis is the theoretical study of the interaction between a nucleon and a nucleus. This is a fundamental method to study the structure and dynamics of nuclear systems. This thesis concentrates on the study of nucleon scattering on light nuclei, ⁶Li, ⁷Li and ¹⁴N, with the effective interaction M3Y and its modification by adding a Skyrme force. This is the first time the Skyrme interaction has been employed in scattering calculations. From a comparison of the measured differential cross section σ (θ) and the analyzing power Ay (θ) for ⁶Li …

Fundamental Investigation Of Vesicle Bilayer Membrane Dynamics, Wilson Okumu

Masters Theses

We studied the bilayer of vesicles from dimyristolyphosphatidylcholine (DMPC), using nitrobenzoxadiazole (NBD) probes, attached to the head (NBD-PE) and the tail (NBD-PC) of phospholipid derivatives. We characterized the bilayer as it underwent reversible transition from the gel to the fluid through a phase transition range. The main phase transition was characterized by steady state and timeresolved fluorescence anisotropy, fluorescence intensity decrement and kinetics of dithionite reduction. We also studied DMPC with dihydrocholesterol. Differences between the surface and interior regions of the bilayer region were obtained. The activation barrier was enthalpic in the gel, entropic in the fluid phase and anomalous …

Estimating Sea Level Due To Crustal Stretching In The Margin Of The Indian Ocean, Kisa Mwakanyamale

Masters Theses

Continental crust extension is a precursor to the formation of a new ocean. The overall crustal extension causes change in the volume of global oceans hence change in sea level. The break-up of Gondwana that began during Late Triassic to Early Jurassic time caused continental crustal extension prior to forming the Indian Ocean. Extension started 184 Ma with rifting between SE Africa, Madagascar and Antarctica. This was followed by rifting between Greater India, Australia and Antarctica beginning about 160 Ma. The most recent episode of extension occurred 34 Ma involving separation between Arabia and Horn of Africa. Gridded data sets …

Geosciences Newsletter- 2007, Department Of Geosciences

Geological and Environmental Sciences News

Vol. 2, No. 3

• Dear Friends and Alumni
• Faculty News
• Publications
• Grants
• Michigan Geological Repository for Research and Education
• Department Updates
• Graduate Student News
• Internships
• Awards and Graduations
• Alumni News
• Donations

Modified Fenton Oxidation Of Hydrocarbon Contaminated Soils With Cao2: Microbial Survival And Surfactant Production, Abraham Matthew Northup

Dissertations

The efficacy of CaO₂ for use in modified Fenton's (MF) reactions was investigated in this study, with the goal of developing a CaO₂-based MF oxidation technology for use in in situ chemical oxidation. Traditionally, liquid H₂O₂ (HP) is used, and is injected into the subsurface in excess to ensure a sufficient radius of influence. CaO₂ was investigated as an alternative source of H₂O₂ for MF reactions.

First, the rate of dissolution of powdered CaO₂ and the yield of HP was investigated. Our results showed that the rate of dissolution …

Synthesis And Characterization Of Doped Core/Shell Quantum Dots, Elizabeth J. Sodt

Masters Theses

The central theme of the research performed is the systematic modification of the optical properties of quantum dots by the formation of a shell of another quantum dot of a different band gap energy. Core/shell quantum dots such as CdS:Mn/CdS, CdS:Mn/ZnS, and ZnS:Mn/CdS with various concentrations of dopant Mn²⁺ in the core and shell concentrations have been synthesized under mild conditions in the aqueous phase using stoichiometric amounts of the surfactant stabilizer dodecyl sulfate. These quantum dots exhibit UV-vis, emission, and electron paramagnetic resonance (EPR) spectral behavior that is dependent on the concentration of the shell and the dopant …

The Effect Of Chloramphenicol On Bb88 Murine Erythroleukemia Cells, Peter K. W. Harris

Dissertations

DNA microarrays can be used to measure genome-wide transcript levels. These measurements may be useful in understanding cellular changes induced by a chemical agent. In this study, Affymetrix microarray technology has been used to study the effects of chloramphenicol, an antibiotic that inhibits bacterial and mitochondrial protein synthesis, on the transcription profile in mammalian cells. Transcript levels in BB88 murine erythroleukemia cells treated with 50 micromolar ( mu M) chloramphenicol, a concentration shown to inhibit BB88 proliferation, are measured. Using total RNA from treated cells, biotin-labeled cRNA was prepared and hybridized to Affymetrix U74Av2 microarrays. From these hybridizations, expression levels …

Wireless Passive Surface Acoustic Wave (Saw) Sensing System, Sridevi Krishnamurthy

Dissertations

Due to their small size and ruggedness, Surface Acoustic Wave (SAW) devices have been widely used as part of wireless sensing or identification system especially in inaccessible and inhospitable environments. In addition, SAW devices find widespread applications as filters in communication systems and also as physical, chemical and bio-sensors and ID tags. The passive wireless SAW sensing system mainly consists of a passive SAW sensor and an interrogation unit which sends a burst signal to the SAW sensor and processes the sensor response. Theobjectives of this work were designing, prototyping and fabricating the interrogation unit on a PCB and also …

Nitrogen Heterocyclic Compounds As Receptors In Nanosensors For Nerve Gas Agent Analogs, Swapna Katram

Masters Theses

The research is focused on developing nanosensors consisting of different components that are chemically linked, namely, nanoparticle, fluorescent monomer, and receptor (NMR sensors) and nanoparticle, monomer, nanomolecule, and receptor (NMNR sensors) for the sensitive and selective detection of nerve gas agents. These sensors detect the target toxins by fluorescence change which is amplified by signal transduction. Model nerve gas toxins (DCP) and (DMMP) and HCl were employed as analytes, and the nitrogen heterocyclic compounds, 5-aminoindazole and dipyrido[3,2-a:2',3'-c]phenazine (dppz) as receptors in the NMR and NNMR nanosensors. The monomers were (E)-4-(4- formylstyryl) benzoic acid (NMR sensor) and 2-mercaptosuccinic acid (NNMR sensor). …

Physics Department News, June 2007, College Of Arts And Sciences

Physics Newsletter

Contents from Volume 6, Issue 1:

• What’s New at the University
• Faculty Highlights
• Alumni Achievement Awards
• More Alumni News
• Staff Highlights
• Soga Center Opens
• Student News
• Annual Student Awards
• Recent Graduates
• Book Awards
• Department Roster
• Feedback Form

Some Applications Of Gaussian Quadrature And Neural Network Modeling In Earth Flows And Other Slow-Moving Landslides In Cohesive Slope Materials, Rennie Bwalya Kaunda

Dissertations

Geometrical changes and progressive displacements in earth flows and other slow moving landslides triggered by climatic changes may be addressed by digital modeling. Gaussian quadrature, a numerical integration technique though fixed points, is employed to compute geometrical areas defined by stratigraphic (soil or rock layering) units, vertical pole projections and a slip surface, based on kinematic admissibility. An example from the Lake Michigan coast shows that the total internal geometrical area is found to be preserved during the course of the progressive deformation. Displacement monitoring of the slope shows that it became less stable over a period of eleven years …

The Fock Space And Related Bergman Type Integral Operators, Ovidiu Furdui

Dissertations

In this thesis we study the boundedness of a general class of integral operators induced by the kernel functions of Fock spaces. More precisely, for a, b, and c real parameters we study the action of [Special characters omitted.] and [Special characters omitted.] on Lp ([Special characters omitted.] ,dv_s ), where dv_s ( z ) = [Special characters omitted.] is the Gaussian probability measure on [Special characters omitted.] . We prove that, when p > 1, respectively p = 1, these operators are bounded if and only if p satisfies a quadratic, respectively a linear, inequality. The …

Measures Of Travers Ability In Graphs, Futaba Okamoto

Dissertations

For a connected graph G of order n ≥ 3 and a cyclic ordering sc : v 1, v2,..., vn, v n+1 = v1 of vertices of G, the number d(sc) is defined by d(sc) = i=1n d(vi, vi +1), where d(vi, vi +1) is the distance between vi and vi+1 in G for 1 ≤ i ≤ n. The Hamiltonian number h(G) and upper Hamiltonian number h +(G) of G are defined as h(G) = min{d(sc)} and h+(G) = max{d(sc)}, respectively, where the minimum and maximum are taken over all cyclic orderings s c of vertices of G. For …

A New Model For Cooperative Mobility In Support If Qos In Manets With Heterogeneous Autonomy Requirements, Ghassen Ben Brahim

Dissertations

Modern mobile ad-hoc networks (MANETs) frequently consist of nodes which exhibit a wide range of autonomy needs. This is particularly true in the settings where MANETs are model compelling, i.e. battlefield, response & rescue, and contexts requiring rapid deployment of mobile users. The time-critical nature of the underlying circumstances frequently requires deployment of both manned and unmanned nodes, and a coordination structure which provides prioritized tasking to them.

In classic ad-hoc networks settings, it is assumed that all nodes are autonomous and do not depend in any case on other nodes. In this research work, contrarily to this design, we …

The Global Hepatic Transcriptional Response Of Male Fisher Rats To Dietary Aroclor 1254 Exposure, Trisha M. Basford

Dissertations

Dietary intake is a primary route for biomagnification of environmentally persistent polychlorinated biphenyls (PCBs) within humans and animals. Aroclor 1254, a mixture of PCBs, is associated with a variety of toxic responses including alterations in blood and lipid biochemistry and tumor promotion. Measurement of the transcriptional responses to low-level dietary exposure to A1254 has not been reported to date, and is important given the persistence of PCBs, and range of effects associated with exposure. The aims of this study were to characterize changes in rat hepatic global gene expression due to sub-acute and sub-chronic dietary exposure to A1254, and to …

Inelastic X-Ray Scattering Studies On Organic Semiconductors And Organic Superconductors, Chaminda Nalaka Kodituwakku

Dissertations

We have measured electronic excitations and excitons in CuPc polycrystalline and single crystal samples. Measurements on the polycrystalline sample were done with 300 meV resolution and measurements on the single crystal were done using 120 meV resolution. Time dependant density functional theory (TD-DFT) calculations were done on the CuPc molecule to understand the electronic excitations in this system.

Towards A Better Understanding Of The Hydrology Of The Tigris- Euphrates System And Its Marshlands, Christopher K. Jones

Masters Theses

Rising demands for fresh water supplies are leading to water management practices that are altering natural flow systems world-wide. One of the most devastated of these natural systems is the Tigris-Euphrates watershed that over the past three decades has witnessed the construction of over 60 engineering projects that eliminated seasonal flooding, reduced natural flow and dramatically reduced the areal extent (1966: 11000 km² ; 2002: 750 km²) of the Mesopotamian Marshes downstream. We constructed a continuous (1964 to 1998) catchment-based rainfall runoff model for the entire Tigris-Euphrates watershed (area: one million km²) using the SWAT …

Laboratory Based Chemical And Isotopic Investigations On Biotic (Microbial) And Abiotic Reduction Of Iron And Oxidation Of Organic Compounds, Tsigabu Asmelash Gebrehiwet

Dissertations

Studies using chemical and isotopic techniques have been conducted to investigate experimental microbial (biotic) iron reduction and abiotic redox processes. In the microbially mediated study Fe(III) reduction and lactate oxidation at circum-neutral pH and anaerobic conditions were used to characterize the metabolic pathways followed by dissimilatory Fe⁺³ -reducing bacterium Shewanella putrefaciens strain 200R. Iron (II), Iron (III), dissolved inorganic carbon (DIC) and carbon isotope ratios were measured under bicarbonate and phosphate buffered conditions. Carbon isotope disproportionation among organic carbon substrate (lactate), biomass and respired carbon dioxide at the lag to stationary phase of the microbial growth curve showed …