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Full-Text Articles in Physical Sciences and Mathematics

Lead Detection In Water: Using Hydroxyapatite And Atomic Absorption, Nicolas Cantarero Jul 2009

Lead Detection In Water: Using Hydroxyapatite And Atomic Absorption, Nicolas Cantarero

Department of Environmental Studies: Undergraduate Student Theses

Hydroxyapatite is a mineral that is very inexpensive, easily made, and binds well to lead. In this procedure its application will be paired with Flame Atomic Absorption Spectroscopy (Flame AA) to detect lead concentrations in water to ppb levels. While ppb concentrations of lead are too dilute to produce a response from the Flame AA by using Hydroxyapatite to concentrate lead molecules from a larger volume and dissolving the Hydroxyapatite into a smaller volume it may be able to produce a response. The method could provide an inexpensive, efficient, and accurate way to detect lead concentrations to the ppb level …


Structure And Mechanism Of Copper- And Nickel-Substituted Analogues Of Metallo-Β-Lactamase L1, Zhenxin Hu, Lauren J. Spadafora, Christine E. Hajdin, Brian Bennett, Michael W. Crowder Apr 2009

Structure And Mechanism Of Copper- And Nickel-Substituted Analogues Of Metallo-Β-Lactamase L1, Zhenxin Hu, Lauren J. Spadafora, Christine E. Hajdin, Brian Bennett, Michael W. Crowder

Physics Faculty Research and Publications

In an effort to further probe metal binding to metallo-β-lactamase L1 (mβl L1), Cu- (Cu-L1) and Ni-substituted (Ni-L1) L1 were prepared and characterized by kinetic and spectroscopic studies. Cu-L1 bound 1.7 equiv of Cu and small amounts of Zn(II) and Fe. The EPR spectrum of Cu-L1 exhibited two overlapping, axial signals, indicative of type 2 sites with distinct affinities for Cu(II). Both signals indicated multiple nitrogen ligands. Despite the expected proximity of the Cu(II) ions, however, only indirect evidence was found for spin−spin coupling. Cu-L1 exhibited higher kcat (96 s−1) and Km (224 μM) values, as …


Microwave Absorption Measurements Using Broad-Band Meanderline Approach, Ching-Ching Tsai, J Choi, Sunglae Cho, S J. Lee, Bimal K. Sarma, C Thompson, O Chernyashevskyy, Ivan Nevirkovets, J B. Ketterson Jan 2009

Microwave Absorption Measurements Using Broad-Band Meanderline Approach, Ching-Ching Tsai, J Choi, Sunglae Cho, S J. Lee, Bimal K. Sarma, C Thompson, O Chernyashevskyy, Ivan Nevirkovets, J B. Ketterson

Australian Institute for Innovative Materials - Papers

We describe a technique that permits broad-band, field-dependent ferromagnetic and electron paramagnetic resonance absorption measurements that is applicable to thin films and patterned micro-/nanostructured arrays and is based on a wire-wound meanderline approach. Techniques to prepare meanderlines and perform microwave measurements are described along with some demonstrations involving an electron paramagnetic resonance calibration/test material, 2,2-diphenyl-1-picryl-hydrazyl, and a ferromagnetic cobalt thin film.


Effective Medium Theory, Rough Surfaces, And Moth’S Eyes, David D. Allred, Zephne Larsen, Joseph Muhlestein, R. Steven Turley, Anthony Willey Jan 2009

Effective Medium Theory, Rough Surfaces, And Moth’S Eyes, David D. Allred, Zephne Larsen, Joseph Muhlestein, R. Steven Turley, Anthony Willey

Faculty Publications

Optics in the extreme ultraviolet (XUV) have important applications in microelectronics, microscopy, space physics, and in imaging plasmas. Because of the short wavelengths involved in these applications, it is critical to account for interfacial roughness to accurately predict the reflection and absorption of XUV optics. This paper examines two possible effects of roughness on optical absorption, non-specular reflection and enhanced transmission and compares these to measured experimental data on a rough Y2O3 thin film.


Enhanced Absorption Metal Oxides For Photocatalytic Applications, Reenamole Georgekutty Jan 2009

Enhanced Absorption Metal Oxides For Photocatalytic Applications, Reenamole Georgekutty

Doctoral

Environmental pollution and industrialization on a global scale has drawn attention to the vital need for developing new hygienic and environmentally friendly purification technologies. The most common indoor and outdoor purification process have their corresponding limitations of electricity and/or other energy sources. To address such enormous tasks, advance oxidation technology like heterogeneous photocatalytic systems via metal oxide semiconductors such as TiO2, ZnO, that are capable to operate effectively and efficiently under UV and visible light must be established. Due to the wide band gap of semiconductors, they are unable to absorb visible light. Hence, numerous research efforts have been done …