Physics Commons^™

Theoretical Investigation On Optical Properties Of 2d Materials And Mechanical Properties Of Polymer Composites At Molecular Level, Geeta Sachdeva

Dissertations, Master's Theses and Master's Reports

The field of two-dimensional (2D) layered materials provides a new platform for studying diverse physical phenomena that are scientifically interesting and relevant for technological applications. Theoretical predictions from atomically resolved computational simulations of 2D materials play a pivotal role in designing and advancing these developments. The focus of this thesis is 2D materials especially graphene and BN studied using density functional theory (DFT) and molecular dynamics (MD) simulations. In the first half of the thesis, the electronic structure and optical properties are discussed for graphene, antimonene, and borophene. It is found that the absorbance in (atomically flat) multilayer antimonene (group …

Richardsite, Zn2cugas4, A New Gallium-Essential Member Of The Stannite Group From The Gem Mines Near Merelani, Tanzania, Luca Bindi, John A. Jaszczak

Michigan Tech Publications

The new mineral richardsite occurs as overgrowths of small (50–400 μm) dark gray, disphenoidal crystals with no evident twinning, but epitaxically oriented on wurtzite–sphalerite crystals from the gem mines near Merelani, Lelatema Mountains, Simanjiro District, Manyara Region, Tanzania. Associated minerals also include graphite, diopside, and Ge,Ga-rich wurtzite. It is brittle, dark gray in color, and has a metallic luster. It appears dark bluish gray in reflected plane-polarized light, and is moderately bireflectant. It is distinctly anisotropic with violet to light-blue rotation tints with crossed polarizers. Reflectance percentages for Rmin and Rmax in air at the respective wavelengths are 23.5, 25.0 …

Extensive Soot Compaction By Cloud Processing From Laboratory And Field Observations, Janarjan Bhandari, Swarup China, Kamal Kant Chandrakar, Greg Kinney, Will Cantrell, Raymond Shaw, Lynn Mazzoleni, Giulia Girotto, Noopur Sharma, Kyle Gorkowski, Stefania Gilardoni, Stefano Decesari, Maria Cristina Facchini, Nicola Zanca, Giulia Pavese, Francesco Esposito, Manvendra K Dubey, Allison C Aiken, Rajan K Chakrabarty, Hans Moosmüller, Timothy B Onasch, Rahul A Zaveri, Barbara V Scarnato, Paulo Fialho, Claudio Mazzoleni

Michigan Tech Publications

Soot particles form during combustion of carbonaceous materials and impact climate and air quality. When freshly emitted, they are typically fractal-like aggregates. After atmospheric aging, they can act as cloud condensation nuclei, and water condensation or evaporation restructure them to more compact aggregates, affecting their optical, aerodynamic, and surface properties. Here we survey the morphology of ambient soot particles from various locations and different environmental and aging conditions. We used electron microscopy and show extensive soot compaction after cloud processing. We further performed laboratory experiments to simulate atmospheric cloud processing under controlled conditions. We find that soot particles sampled after …

Energy Transfer Between Eu2+ And Mn2+ For Na(Sr,Ba)Po4 And Ba2mg(Bo3)2, Kevin Bertschinger

Dissertations, Master's Theses and Master's Reports

There is no debate of the affect that solid-state lighting has had on the world we live in. Throughout the centuries, lighting has continued to improve from kerosene lanterns to white light emitting diodes. Even though lighting today is sufficient there is still much room to improve color rendering index and efficiency. An active area of research to improve today's lighting technology is by doping inorganic phosphors with luminescent ion centers. There have been numerous reports of inorganic phosphors showing a variety of emission color and luminescence. In this thesis we discuss two new inorganic phosphors codoped with Eu^{2+ …}

Molecular And Physical Characteristics Of Aerosol At A Remote Free Troposphere Site: Implications For Atmospheric Aging, Simeon Schum, Bo Zhang, Katja Džepina, Paolo Fialho, Claudio Mazzoleni, Lynn Mazzoleni

Department of Chemistry Publications

Aerosol properties are transformed by atmospheric processes during long-range transport and play a key role in the Earth's radiative balance. To understand the molecular and physical characteristics of free tropospheric aerosol, we studied samples collected at the Pico Mountain Observatory in the North Atlantic. The observatory is located in the marine free troposphere at 2225m above sea level, on Pico Island in the Azores archipelago. The site is ideal for the study of long-range-transported free tropospheric aerosol with minimal local influence. Three aerosol samples with elevated organic carbon concentrations were selected for detailed analysis. FLEXPART retroplumes indicated that two of …

Light Absorption By Polar And Non-Polar Aerosol Compounds From Laboratory Biomass Combustion, Deep Sengupta, Vera Samburova, Chiranjiva Bhattarai, Elena Kirillova, Lynn Mazzoleni, Michealene Iaukea-Lum, Adam Watts, Audrey Khlystov

Department of Chemistry Publications

Fresh and atmospherically aged biomass-burning (BB) aerosol mass is mostly comprised of strongly light-absorbing black carbon (BC) and of organic carbon (OC) with its light-absorbing fraction – brown carbon (BrC). There is a lack of data on the physical and chemical properties of atmospheric BB aerosols, leading to high uncertainties in estimates of the BB impact on air quality and climate, especially for BrC. The polarity of chemical compounds influences their fate in the atmosphere including wet/dry deposition and chemical and physical processing. So far, most of the attention has been given to the water-soluble (polar) fraction of BrC, while …

Multi-Mode And Single Mode Polymer Waveguides And Structures For Short-Haul Optical Interconnects, Kevin L. Kruse

Dissertations, Master's Theses and Master's Reports - Open

Single mode and multi-mode polymer optical waveguides are a viable solution for replacing copper interconnects as high speed and large bandwidth short-haul optical interconnects in next-generation supercomputers and data servers. A precision laser direct writing method is implemented for producing various single mode and multi-mode polymer waveguide structures and their performance is evaluated experimentally showing agreement with theoretically developed models. The laser direct writing method is the optimal solution for low-rate cost-effective prototyping and large area panel production.

A single mode polymer waveguide bridge module for silicon to glass optical fibers is designed, modeled, fabricated, and measured. The bridge module …

A Semi-Lagrangian View Of Ozone Production Tendency In North American Outflow In The Summers Of 2009 And 2010, B. Zhang, R. C. Owen, J A Perlinger, A. Kumar, S. Wu, M. Val Martin, L. Kramer, D. Helmig, R. E. Honrath

Michigan Tech Publications

The Pico Mountain Observatory, located at 2225 m a.s.l. in the Azores Islands, was established in 2001 to observe long-range transport from North America to the central North Atlantic. In previous research conducted at the observatory, ozone enhancement (> 55 ppbv) in North American outflows was observed, and efficient ozone production in these outflows was postulated. This study is focused on determining the causes for high d[O3] / d[CO] values (~1 ppbv ppbv−1) observed in the summers of 2009 and 2010. The folded retroplume technique, developed by Owen and Honrath (2009), was applied to combine upwind FLEXPART transport …