Physical Sciences and Mathematics Commons^™

Dropwise Condensation Dynamics In Humid Air, Julian Eduardo Castillo Chaco

Open Access Theses

Dropwise condensation of atmospheric water vapor is important in multiple practical engineering applications. The roles of environmental factors and surface morphology/chemistry on the condensation dynamics need to be better understood to enable efficient water-harvesting, dehumidication, and other psychrometric processes. Systems and surfaces that promote faster condensation rates and self-shedding of condensate droplets could lead to improved mass transfer rates and higher water yields in harvesting applications. The thesis presents the design and construction of an experimental facility that allows visualization of the condensation process as a function of relative humidity. Dropwise condensation experiments are performed on a vertically oriented, hydrophobic …

New Strategies To Reveal Protein Candidates In Protein-Protein Interactome Study, Meng-Chieh Chen

Open Access Theses

Comprehensive protein-protein interaction network analysis can help reveal protein functions in a system-wide manner. A reliable knowledgebase of interaction networks is not only important for selecting the candidates for drug therapies, but also for evaluating the disease risk. In current interaction databases, 322579 interactions comprised of 56460 proteins have been reported (statistical analysis from APID: Agile Protein Interaction DataAnalyzer; http://bioinfow.dep.usal.es/apid/index.htm). The huge datasets are contributed mainly by yeast -two -hybrid (Y2H) screening and affinity-purification followed by mass spectrometry (AP-MS). High false positive rates and failing to cover certain interaction categories are the limitations of these two methods. Here, we developed …

Application Of Bayesian Networks In Consumer Service Industry, Yuan Gao

Open Access Theses

Gao, Yuan. M.S.I.E., Purdue University. December 2014. Application of Bayesian Networks in Consumer Service Industry. Major professor: Vincent G. Duffy The purpose of the present study is to explore the application of Bayesian networks in the consumer service industry to model causal relationships within complex risk factor structures using aggregate data. An analysis of the Hawaii tourism market was conducted to find out how visitor characteristics affect their behavior and experience as consumers during the trips, and influence the tourism market outcomes represented by measurable factors. Two hypotheses were proposed regarding the use of aggregate data and the influence of …

High-Purity Gallium Analysis By Inductively Coupled Plasma Mass Spectrometry, Kyungjean Min

Open Access Theses

The mobility of Two-dimensional Electron Gas in AlGaAs/GaAs heterostructures that are grown in the Molecular Beam Epitaxy (MBE) can be increased by purification of the gallium used to grow the films. To attain 200 million cm2/Vs mobility, the impurity concentration of gallium should be reduced to below 1 ppb. The commercial 7N (99.99999%) gallium with 100 ppb total impurity is currently used in the MBE at Purdue University and is being purified by zone refining. To evaluate the commercial 7N gallium and establish the methodology for the impurity measurement after zone refining, germanium, iron, and zinc in 6N and 7N …

Elucidating The Mechanism Of Phenylpropanoid Regulation By The Arabidopsis Mediator Complex, Wenjie Zeng

Open Access Theses

The Mediator complex is a multi-protein co-regulator of eukaryotic transcription which plays a role in the expression of many, if not most, genes of the cell. Two Mediator subunits, REF4 and RFR1, were demonstrated to be important for the normal regulation of phenylpropanoid metabolism in Arabidopsis. Phenylpropanoids are a family of specialized plant metabolites derived from the amino acid phenylalanine and are involved in defense against pathogens, UV protection and structural support. In order to understand how Mediator regulates phenylpropanoid metabolism through REF4 and RFR1, a better basic understanding of this protein complex is required. Here I provide data on …

Reverse-Phase Liquid Chromatography Of Small Molecules Using Silica Colloidal Crystals, Natalya Khanina

Open Access Theses

Capillaries packed with a silica colloidal crystal (SCC) of 470 nm nonporous particles have recently been shown to offer significant improvements in the peak width, resolution, and speed of protein analysis due to the reduction of the A and C term broadening contributions of the Van Deemter equation. While protein separations using this technology have shown vast improvements, small molecules remain largely unexplored. As the SCC allows for an approximately diffusion limited system, extremely high plate numbers are expected for small molecule separations. The research presented herein studies the feasibility of pressure-driven small molecule separation using SCCs and commercial instrumentation. …

Propogation Of Wind Turbine Noise Through Wakes And Turbulent Atmosphere, Yuan Peng

Open Access Theses

It is well known that the atmospheric inhomogeneities have great impact on sound propagation over long ranges. For the application of predicting wind turbine noise, either the flow wakes generated by rotating turbine blades or small-scale atmospheric turbulence can affect the propagation of sound over ground surfaces from individual turbines.

In this thesis, the effects of wake and atmospheric turbulence on the propagation of wind turbine noise are investigated. By introducing the Parabolic Equation (PE) method, the effects of atmospheric changes in sound speed can be incorporated at each marching step as the prediction of sound field advances in the …

Identifying Conditions To Optimize Lactic Acid Production From Food Waste, Raymond M. Redcorn

Open Access Theses

There is an increased demand for lactic acid for the production of biopolymers and to aid nutrient removal in wastewater treatment. Food waste offers a source of soluble sugars to produce lactic acid, which does not increase land demand, but digestion conditions have yet to be optimized when co-digested with primary sludge. Food waste was collected from cafeteria waste bins, homogenized and seeded with primary sludge. A Box Behnken Response surface design was used to optimize lactic acid production based on pH, temperature, loading rate, and retention time. Subsequent experiments verified and refined those conditions to optimize for both yield …

Impact Of Nanostructure On Polymer-Based Nonvolatile Memory Devices, Seung Hyun Sung

Open Access Theses

Memory functionality is essential for many high-end electronic applications (e.g. , smart phones, personal computers). Particularly, organic nonvolatile memory devices based on polymer ferroelectric materials are a promising approach toward the development of low-cost memory due to the ease of processing and flexibility associated with the device. Here, we will focus on a memory device with a two-component active layer and a diode structure. This ferroelectric diode (FeD) has a nanostructured active layer, composed of ferroelectric and semiconducting polymers, and it can provide easy access to high-performance polymer-based memory devices. In order to create these nanostructured active layers, we …

Gas-Phase Ion/Ion Reactions Of Biomolecules: An Examination Of Carboxylate Reactivity And Arginine Based Non-Covalent Complexes, Nathan Zachary Barefoot

Open Access Theses

The advent of Electrospray Ionization with the ability to generate multiply charges ions has contributed significantly to the study of gas-phase ion/ion reactions. With the tools available in mass spectrometry it has been shown that these reactions are effective at transforming one type of gaseous ion into another through a series of reactions. This work examines some of these reactions and their application to field of proteomics specifically focusing on the amino acids of arginine and lysine. NHS reagents have been shown to react to both of these molecules with in the gas-phase under different conditions but have relies on …

Correlating Molecular Architecture Of A Radical Polymer Based Copolymer With Its Electrical Transport Properties, Holly Chan

Open Access Theses

The design and synthesis of electrically-conductive macromolecules can lead to significant improvements in the performance of polymer-based energy conversion devices (e.g., thermoelectric devices). For these organic electronic devices, conjugated polymers have dominated the area of conductive polymers; however, these materials are usually synthesized using conditions that lead to poorly-defined polymers. Furthermore, in these increasingly-standard polymers, the charge transport ability of the polymer thin films is largely affected by the degree of crystallinity, which is a difficult property to control in a reproducible fashion. Therefore, we seek to explore a new class of amorphous, non-conjugated polymers containing a stable radical …

Separation Of On-Column Labeled Model Proteins With Packed Capillary Electrophoresis, Yingxu Hao

Open Access Theses

Protein drugs are increasingly developed in the pharmaceutical company. Under the regulation of FDA, high purity of therapeutic proteins needs to be maintained. Before putting those drugs in the market, fast and efficient method is in need to achieve homogeneity. Traditionally, polyacrylamide gel electrophoresis (PAGE), capillary electrophoresis (CE), and size-exclusion chromatography (SEC) are used for the purification process. These methods have the disadvantages of low time and cost efficiency, and this quality assurance process has become the bottleneck of production. In our group, sub-micron silica colloidal particles with polyacrylamide layer on the surface are packed inside capillaries to increase the …

Optical Position Sensing In Free Space Optical Communication, Muhammad Salman Bashir

Open Access Theses

In this thesis the performance of three estimators, (center of gravity, template matching and maximum likelihood (MLE)) to estimate the center of the beam on a photoemissive receiver array in a Free Space Optics (FSO) system, is compared in terms of mean square error. Simulations have been conducted in Matlab by generating a two dimensional nonhomogeneous Poisson process, and, mean square error is computed for three estimators. The cases of continuous and discrete arrays are also considered for various levels of signal-to-noise (SNR) ratio. Simulations have shown that the MLE gives the least mean squared error and especially performs significantly …

Feasibility Analysis Of Large Length-Scale Thermocapillary Flow Experiment For The International Space Station, Samantha Jean Alberts

Open Access Theses

The investigation of microgravity fluid dynamics emerged out of necessity with the advent of space exploration. In particular, capillary research took a leap forward in the 1960s with regards to liquid settling and interfacial dynamics. Due to inherent temperature variations in large spacecraft liquid systems, such as fuel tanks, forces develop on gas-liquid interfaces which induce thermocapillary flows. To date, thermocapillary flows have been studied in small, idealized research geometries usually under terrestrial conditions. The 1 to 3m lengths in current and future large tanks and hardware are designed based on hardware rather than research, which leaves spaceflight systems designers …

Drift-Flux Correlation Development For Two-Phase Flow In Rod Bundles, Collin M. Clark

Open Access Theses

A rod bundle drift-flux correlation is developed with intended application across a wide range of two-phase flow conditions. Special consideration is made for fluid flow mechanisms at low liquid velocity and low pressure conditions. In these instances, gravitational forces from the density difference of the associated fluid phases are more significant. Secondary flow patterns may develop as a result and a drift-flux correlation would need to make appropriate adjustments. Earlier correlations may have increased error at these conditions if they have been formulated with respect to relatively higher pressures or flow rates. In the present work, area-average void fraction data …

The Development Of 6.7% Efficient Copper Zinc Indium Selenide Devices From Copper Zinc Indium Sulfide Nanocrystal Inks, Brian Kemp Graeser

Open Access Theses

As solar cell absorber materials, alloys of CuIn(S,Se)2 and Zn(S,Se) provide an opportunity to reduce the usage of indium along with the ability to tune the band gap. Here we report successful synthesis of alloyed (CuInS2 )0.5(ZnS)0.5 nanocrystals by a method that solely uses oleylamine as the liquid medium for synthesis. The reactive sintering of a thin film of these nanocrystals via selenization at 500 °C results in a uniform composition alloy (CuIn(S,Se)2 )0.5 (Zn(S,Se)) 0.5 layer with micron size grains. Due to the large amount of zinc in the film, the sintered grains exhibit the zinc blende structure instead …

Investigation Of Isotope Effects Of Ozone As A Function Of Temperature, Daniel J. Mcmahon

Open Access Theses

Ozone is an important oxidizer in the atmosphere and plays a crucial role as a cleanser, removing various compounds such NOx and SOx. It also is intriguing to those that study stable isotopes as it has a unique signature found in no other oxygen containing molecule. Ozone is observed to fractionate mass independently, which means it does not follow the typical δ 17 O /δ18 O = 0.52 ratio expected for molecules enriched with 17 O and 18 O. The magnitude of ozone's mass independent enrichment has been studied in laboratory experiments and atmospheric observations but its explanation is still …

Applications Of Calculated Second Harmonic Generation Tensors On Monomolecular And Bimolecular Systems, Gregory R. Snyder

Open Access Theses

The field of nonlinear optics (NLO) has proven itself as a relatively recent and powerful area of science in the areas of microscopy and high-sensitivity quantification measurements. In particular, symmetry selective NLO processes such as second harmonic generation (SHG) take advantage of symmetry rules to cancel background noise almost completely, leading to both high resolution images and limits of detection (LOD) in the photon counting range. Background noise in SHG is negated as result of signal cancellation in systems containing inversion symmetry; generally isotropic sources. Quantum mechanical computational chemistry has enriched the field of NLO by enabling studies on hypothetical …

Effect Of Multivalent Ions On The Swelling And Mechanical Behavior Of Superabsorbent Polymers (Saps) For Mitigation Of Mortar Autogenous Shrinkage, Qian Zhu

Open Access Theses

The chemical and physical structure-property relationships of model superabsorbent polymer (SAP) hydrogels were characterized with respect to swelling behavior and mechanical properties in different ionic solutions (Na+ , Ca2+ , and Al3+ ). The model hydrogels were composed of poly(sodium acrylate-acrylamide) (PANa-PAM) copolymer with varying concentrations of PANa (0, 17, 33, 67, and 83 wt.%) and covalent crosslinking densities of 1, 1.5, and 2 wt.%. By synthesizing the hydrogels in-house, systems with independently tunable amounts of covalent crosslinking and anionic functional groups were created, allowing for the relative effects of covalent and ionic crosslinking on the properties of the hydrogels …

Protein Affinity Extraction Of Prostate Specific Antigen (Psa) Using Submicron Spheres, Yao Wang

Open Access Theses

PSA has been used as a biomarker for prostate cancer for a long time. To characterize different glycoforms of PSA using techniques like UHPLC and cIEF, concentration and purification of PSA from complex samples becomes necessary. Our group has developed submicron silica spheres based affinity beads to extract PSA through immunoprecipitation. This study focuses on measuring the bead performance when antibody type/amount was varied and PSA concentration was lowered for clinical use. To better satisfy the requirement of large-scale extraction, several attempts were made to increase the bead capacity. The results will be presented and future directions of the project …