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Articles 1 - 20 of 20
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A Theoretical And Experimental Investigation Of The Physical And Chemical Properties Of Solid Nanoscale Interfaces, Jeronimo Matos
A Theoretical And Experimental Investigation Of The Physical And Chemical Properties Of Solid Nanoscale Interfaces, Jeronimo Matos
Electronic Theses and Dissertations
With the emerging interest in nanoscale materials, the fascinating field of surface science is rapidly growing and presenting challenges to the design of both experimental and theoretical studies. The primary aim of this dissertation is to shed some light on the physical and chemical properties of selected nanoscale materials at the interface. Furthermore, we will discuss the effective application of cutting edge theoretical and experimental techniques that are invaluable tools for understanding the systems at hand. To this effect, we use density functional theory (DFT) with the inclusion of van der Waals (vdW) interactions to study the effect of long-range …
Quantitative Scanning Transmission Electron Microscopy Of Thick Samples And Of Gold And Silver Nanoparticles On Polymeric Surfaces, Aniruddha Dutta
Quantitative Scanning Transmission Electron Microscopy Of Thick Samples And Of Gold And Silver Nanoparticles On Polymeric Surfaces, Aniruddha Dutta
Electronic Theses and Dissertations
Transmission Electron Microscopy (TEM) is a reliable tool for chemical and structural studies of nanostructured systems. The shape, size and volumes of nanoparticles on surfaces play an important role in surface chemistry. As nanostructured surfaces become increasingly important for catalysis, protective coatings, optical properties, detection of specific molecules, and many other applications, different techniques of TEM can be used to characterize the properties of nanoparticles on surfaces to provide a path for predictability and control of these systems. This dissertation aims to provide fundamental understanding of the surface chemistry of Electroless Metallization onto Polymeric Surfaces (EMPS) through characterization with TEM. …
Cerium Oxide Nanoparticles: Their Phosphatase Activity And Its Control, Atul Dhall
Cerium Oxide Nanoparticles: Their Phosphatase Activity And Its Control, Atul Dhall
Electronic Theses and Dissertations
Cerium oxide nanoparticles are established scavengers of reactive oxygen and nitrogen species. They have many potential biomedical applications that depend on their physicochemical properties and mode of preparation. Recent studies have found these nanoparticles possess phosphatase mimetic activity. Studying such catalytic activities will qualify their biomedical applications and render information on their bioavailability and potential toxicity. Two oxidation states of cerium exist in these nanoparticles (3+ or 4+). It is hypothesized that the oxidation state of cerium in the nanoparticles determines the amount of adsorbed water on the crystal lattices. This in turn governs their activity as phosphatases. Nanoparticles with …
Light-Matter Interactions Of Plasmonic Nanostructures, Jennifer Reed
Light-Matter Interactions Of Plasmonic Nanostructures, Jennifer Reed
Electronic Theses and Dissertations
Light interaction with matter has long been an area of interest throughout history, spanning many fields of study. In recent decades, the investigation of light-matter interactions with nanostructures has become an intense area of research in the field of photonics. Metallic nanostructures, in particular, are of interest due to the interesting properties that arise when interacting with light. The properties are a result of the excitation of surface plasmons which are the collective oscillation of the conduction electrons in the metal. Since the conduction electrons can be thought of as harmonic oscillators, they are quantized in a similar fashion. Just …
X-Ray Radiation Enabled Cancer Detection And Treatment With Nanoparticles, Mainul Hossain
X-Ray Radiation Enabled Cancer Detection And Treatment With Nanoparticles, Mainul Hossain
Electronic Theses and Dissertations
Despite significant improvements in medical sciences over the last decade, cancer still continues to be a major cause of death in humans throughout the world. Parallel to the efforts of understanding the intricacies of cancer biology, researchers are continuously striving to develop effective cancer detection and treatment strategies. Use of nanotechnology in the modern era opens up a wide range of possibilities for diagnostics, therapies and preventive measures for cancer management. Although, existing strategies of cancer detection and treatment, using nanoparticles, have been proven successful in case of cancer imaging and targeted drug deliveries, they are often limited by poor …
Structure, Stability, Vibrational, Thermodynamic, And Catalytic Properties Of Metal Nanostructures: Size, Shape, Support, And Adsorbate Effects, Farzad Behafarid
Structure, Stability, Vibrational, Thermodynamic, And Catalytic Properties Of Metal Nanostructures: Size, Shape, Support, And Adsorbate Effects, Farzad Behafarid
Electronic Theses and Dissertations
Recent advances in nanoscience and technology have provided the scientific community with new exciting opportunities to rationally design and fabricate materials at the nanometer scale with drastically different properties as compared to their bulk counterparts. A variety of challenges related to nanoparticle (NP) synthesis and materials characterization have been tackled , allowing us to make more homogenous, well defined, size- and shape-selected NPs, and to probe deeper and more comprehensively into their distinct properties. In this dissertation, a variety of phenomena relevant to nanosized materials are investigated, including the thermal stability of NPs and coarsening phenomena in different environments, the …
Fate Of Coated Zinc Oxide In Municipal Solid Waste Landfills, Stephanie Carbone Bolyard
Fate Of Coated Zinc Oxide In Municipal Solid Waste Landfills, Stephanie Carbone Bolyard
Electronic Theses and Dissertations
Given the increase in nanomaterial (NM) use in consumer products and the large fraction of waste placed in landfills worldwide, the probability of these products reaching municipal solid waste (MSW) landfills at the end of their useful life is high. Since nanotechnology use is still in its early stages, there are currently no regulations pertaining to the disposal of NMs and their fate in MSW landfills is still unknown. Understanding the fate of NMs in MSW landfills is vital to ensure the proper handling of these novel materials from cradle to grave; such research will provide information on how these …
The Behavior Of Cerium Oxide Nanoparticles In Polymer Electrolyte Membranes In Ex-Situ And In-Situ Fuel Cell Durability Tests, Benjamin Pearman
The Behavior Of Cerium Oxide Nanoparticles In Polymer Electrolyte Membranes In Ex-Situ And In-Situ Fuel Cell Durability Tests, Benjamin Pearman
Electronic Theses and Dissertations
Fuel cells are known for their high efficiency and have the potential to become a major technology for producing clean energy, especially when the fuel, e.g. hydrogen, is produced from renewable energy sources such as wind or solar. Currently, the two main obstacles to wide-spread commercialization are their high cost and the short operational lifetime of certain components. Polymer electrolyte membrane (PEM) fuel cells have been a focus of attention in recent years, due to their use of hydrogen as a fuel, their comparatively low operating temperature and flexibility for use in both stationary and portable (automotive) applications. Perfluorosulfonic acid …
Characterization Of Composite Broad Band Absorbing Conjugated Polymer Nanoparticles Using Steady-State, Time-Resolve And Single Particle Spectroscopy, Maxwell Scotland Bonner
Characterization Of Composite Broad Band Absorbing Conjugated Polymer Nanoparticles Using Steady-State, Time-Resolve And Single Particle Spectroscopy, Maxwell Scotland Bonner
Electronic Theses and Dissertations
As the global economy searches for reliable, inexpensive and environmentally friendly renewable energy resources, energy conservation by means of photovoltaics has seen near exponential growth in the last decade. Compared to state-of-the-art inorganic solar cells, organic photovoltaics (OPVs) composed of conjugated polymers are particularly interesting because of their processability, flexibility and the potential for large area devices at a reduced fabrication cost. It has been extensively documented that the interchain and intrachain interactions of conjugated polymers complicate the fundamental understanding of the optical and electronic properties in the solid-state (i.e. thin film active layer). These interactions are highly dependent on …
Investigations On Morphology, Spectroscopy And Near-Infrared Photoresponse Sensitization Of Conjugated Polymers In Organic Photovoltaics, Zhongjian Hu
Electronic Theses and Dissertations
Conjugated polymer architecture and morphology are two of the key factors that determine corresponding opto-electronic device performance. It is well-known that conjugated polymers display a variety of conformations and exhibit aggregation in their materials and even for individual polymer chains. The intrinsic structural heterogeneity of conjugated polymers strongly complicates the active layer morphology and phase separation, which are crucial for photoinduced charge generation and transport in polymer based bulk heterojunction-organic photovoltaics device (BHJ-OPVs). Aiming to probe the molecular level correlations between conjugated polymer architecture, morphology and optoelectronic properties, single molecule spectroscopy (SMS) and single particle spectroscopy (SPS) were employed. The …
Metal Blacks As Scattering Centers To Increase The Efficiency Of Thin Film Solar Cells, Deep R. Panjwani
Metal Blacks As Scattering Centers To Increase The Efficiency Of Thin Film Solar Cells, Deep R. Panjwani
Electronic Theses and Dissertations
Metal nano particles are investigated as scattering centers on front surface of thin-film solar cells to improve efficiency. The principle is that scattering, which is enhanced near the plasmon resonance frequency of the particle and depends on particle size, increases the effective optical path length of incident light, leading to more light absorption in active layer of thin film solar cell. The particular types of particles investigated here are known as "metal-black", well known as an IR absorber for bolometric infrared detectors. Gold-black was deposited on commercial thin-film solar cells using a thermal evaporator in a nitrogen ambient at pressures …
Synthesis, Structure, And Catalytic Properties Of Size-Selected Platinum Nanoparticles, Simon Armando Covone
Synthesis, Structure, And Catalytic Properties Of Size-Selected Platinum Nanoparticles, Simon Armando Covone
Electronic Theses and Dissertations
The use of heterogeneous catalysis is well established in chemical synthesis, energy, and environmental engineering applications. Supported Pt nanoparticles have been widely reported to act as catalysts in a vast number of chemical reactions. In this report, the performance of Pt/ZrO2 nanocatalyst for the decomposition of methanol, ethanol, 2-propanol, and 2-butanol is investigated. The potential of each alcohol for the production of H2 and other relevant products in the presence of a catalyst is studied. All the alcohols studied show some decomposition activity below 200°C which increased with increasing temperature. In all cases, high selectivity towards H2 formation is observed. …
Magnetic Nanosensors For Multiplexed Bacterial Pathogenesis Identification, Charalambos Kaittanis
Magnetic Nanosensors For Multiplexed Bacterial Pathogenesis Identification, Charalambos Kaittanis
Electronic Theses and Dissertations
Developing diagnostic modalities that utilize nanomaterials and miniaturized detectors can have an impact in point-of-care diagnostics. Diagnostic systems that (i) are sensitive, robust, and portable, (ii) allow detection in clinical samples, (iii) require minimal sample preparation yielding results quickly, and (iv) can simultaneously quantify multiple targets, would have a great potential in biomedical research and public healthcare. Bacterial infections still cause pathogenesis throughout the world (Chapter I). The emergence of multi-drug resistant strains, the potential appearance of bacterial pandemics, the increased occurrence of bacterial nosocomial infections, the wide-scale food poisoning incidents and the use of bacteria in biowarfare highlight the …
Plasmon Enhanced Near-Field Interactions In Surface Coupled Nanoparticle Arrays For Integrated Nanophotonic Devices, Amitabh Ghoshal
Plasmon Enhanced Near-Field Interactions In Surface Coupled Nanoparticle Arrays For Integrated Nanophotonic Devices, Amitabh Ghoshal
Electronic Theses and Dissertations
The current thrust towards developing silicon compatible integrated nanophotonic devices is driven by need to overcome critical challenges in electronic circuit technology related to information bandwidth and thermal management. Surface plasmon nanophotonics represents a hybrid technology at the interface of optics and electronics that could address several of the existing challenges. Surface plasmons are electronic charge density waves that can occur at a metal-dielectric interface at optical and infrared frequencies. Numerous plasmon based integrated optical devices such as waveguides, splitters, resonators and multimode interference devices have been developed, however no standard integrated device for coupling light into nanoscale optical circuits …
Supported Mono And Bimetallic Platinum And Iron Nanoparticles Electronic, Structural, Catalytic, And Vibrational Properties, Jason Robert Croy
Supported Mono And Bimetallic Platinum And Iron Nanoparticles Electronic, Structural, Catalytic, And Vibrational Properties, Jason Robert Croy
Electronic Theses and Dissertations
Catalysis technologies are among the most important in the modern world. They are instrumental in the realization of a variety of products and processes including chemicals, polymers, foods, pharmaceuticals, fuels, and fuel cells. As such, interest in the catalysts that drive these processes is ongoing, and basic research has led to significant advances in the field, including the production of more environmentally friendly catalysts that can be tuned at the molecular/atomic level. However, there are many factors which influence the performance of a catalyst and many unanswered questions still remain. The first part of this work is concerned with the …
Imaging And Spectroscopy Of Conducting Polymer-Fullerene Composite Materials, Daeri Tenery
Imaging And Spectroscopy Of Conducting Polymer-Fullerene Composite Materials, Daeri Tenery
Electronic Theses and Dissertations
Since the development and optical study of conjugated (conducting) polymers it has become apparent that chain conformation and aggregation at the molecular scale result in complex heterogeneous nanostructured bulk materials for which a detailed insight into morphological, spectroscopic as well as optoelectronic properties and mechanisms is overwhelmingly difficult to obtain. Nanoparticles composed of the conjugated polymer poly (MEH-PPV) and nanocomposite nanoparticles consisting of MEH-PPV doped with 1-(3-methoxycarbonylpropyl)-1-phenyl-C61 (PCBM) were prepared as model systems to study these materials at the length scale of one to a few domains. The MEH-PPV and PCBM doped nanoparticles were analyzed by single imaging/particle spectroscopy (SPS) …
In-Situ Gas Phase Catalytic Properties Of Metal Nanoparticles, Luis Ono
In-Situ Gas Phase Catalytic Properties Of Metal Nanoparticles, Luis Ono
Electronic Theses and Dissertations
Recent advances in surface science technology have opened new opportunities for atomic scale studies in the field of nanoparticle (NP) catalysis. The 2007 Nobel Prize of Chemistry awarded to Prof. G. Ertl, a pioneer in introducing surface science techniques to the field of heterogeneous catalysis, shows the importance of the field and revealed some of the fundamental processes of how chemical reactions take place at extended surfaces. However, after several decades of intense research, fundamental understanding on the factors that dominate the activity, selectivity, and stability (life-time) of nanoscale catalysts are still not well understood. This dissertation aims to explore …
Probing And Tuning The Size, Morphology, Chemistry And Structure Of Nanoscale Cerium Oxide, Satyanarayana Kuchibhatla
Probing And Tuning The Size, Morphology, Chemistry And Structure Of Nanoscale Cerium Oxide, Satyanarayana Kuchibhatla
Electronic Theses and Dissertations
Cerium oxide (ceria)-based materials in the nanoscale regime are of significant fundamental and technological interest. Nanoceria in pure and doped forms has current and potential use in solid oxide fuel cells, catalysis, UV- screening, chemical mechanical planarization, oxygen sensors, and bio-medical applications. The characteristic feature of Ce to switch between the +3 and + 4 oxidation states renders oxygen buffering capability to ceria. The ease of this transformation was expected to be enhanced in the nanoceria. In most the practical scenarios, it is necessary to have a stable suspension of ceria nanoparticles (CNPs) over longer periods of time. However, the …
Use Of Cerium Oxide Nanoparticles For Protection Against Radiation-Induced Cell Death, Jimmie Colon
Use Of Cerium Oxide Nanoparticles For Protection Against Radiation-Induced Cell Death, Jimmie Colon
Electronic Theses and Dissertations
The ability of engineered cerium oxide nanoparticles to confer radioprotection was examined. Rat astrocytes were treated with cerium oxide nanoparticles to a final concentration of 10 nanomolar, irradiated with a single 10 Gy dose of ionizing radiation and cell death was evaluated by propidium iodine uptake at 24 and 48 hours after radiation insult. Treatment of rat astrocytes with nanoceria resulted in an approximate 3-fold decrease in radiation induced death. These results suggest that the nanoceria are conferring protection from radiation induced cell death. Further experiments with human cells were conducted. Human normal and tumor cells (MCF-7 and CRL8798) were …
Arc-Discharge In Solution: A Novel Synthesis Method For Carbon Nanotubes And In Situ Decoration Of Carbon Nanotubes With Nanoparticles, Debasis Bera
Electronic Theses and Dissertations
Nanotechnology has reached the status of the 21st century's leading science and technology based on fundamental and applied research during the last two decades. An important feature of nanotechnology is to bridge the crucial dimensional gap between the atomic and molecular fundamental sciences and microstructural scale of engineering. Accordingly, it is very important to have an in-depth understanding of the synthesis of nanomaterials for the use of state-of-the-art high technological devices with enhanced properties. Recently, the 'bottom-up' approach for the fabrication of nanomaterials has received a great deal of attention for its simplicity and cost effectiveness. Tailoring the various parameters …