Engineering Commons^™

Factorial Design Analysis For Dye-Sensitized Hydrogen Generation From Water, Pankaj Chowdhury, Hassan Gomaa, Ajay Ray

PC

A factorial design at two levels and four factors has been carried out in order to investigate the potential for hydrogen generation using Eosin Y-sensitized TiO2/Pt catalyst under visible solar light in presence of triethanolamine (TEOA) as electron donor. The solution pH was found to be a significant parameter, and was maintained at pH 7.0 throughout the investigation. Visible light irradiation time (I-time) showed highest positive effect on hydrogen generation followed by initial Eosin Y concentration (for dye-sensitization) and the TEOA concentration while Pt content (wt %) in TiO2 showed negative effect toward hydrogen generation. Experimental data were analyzed using …

Metamaterials On Parylene Thin Film Substrates: Design, Fabrication, And Characterization At Terahertz Frequency, Xianliang Liu, Samuel Macnaughton, David Shrekenhamer, Hu Tao, Selvapraba Selvarasah, Atcha Totachawattana, Richard Averitt, Mehmet Dokmeci, Sameer Sonkusale, Willie Padilla

Mehmet R. Dokmeci

We design, fabricate, and characterize terahertz (THz) resonant metamaterials on parylene free-standing thin film substrates. Several different metamaterials are investigated and our results show strong electromagnetic responses at THz frequencies ranging from 500 GHz to 2.5 THz. The complex frequency dependent dielectric properties of parylene are determined from inversion of reflection and transmission data, thus indicating that parylene is an ideal low loss substrate or coating material. The biostable and biocompatible properties of parylene coupled with the multifunctional exotic properties of metamaterials indicate great potential for medical purposes such as THz imaging for skin cancer detection.

The Yin And Yang Actions Of North American Ginseng Root In Modulating The Immune Function Of Macrophages, Chike Azike, Paul Charpentier, Jirui Hou, Hua Pei, Edmund Lui

Edmund M. K. Lui

BACKGROUND: Immuno-modulatory effects of ginseng, including both immuno-stimulatory and immuno-suppressive effects, have been widely reported. This study aims to determine whether the paradoxical immuno-modulatory effect is related to unique phytochemical profiles of different North American (NA) ginseng, namely aqueous (AQ) and alcoholic (ALC) extracts.

METHODS: AQ and ALC extracts were prepared and their immuno-bioactivity were studied in vitro in murine macrophages (Raw 264.7) through measuring the direct stimulatory production of pro-inflammatory mediator and cytokines as well as the suppression of lipopolysaccharide (LPS)-stimulatory response by the two extracts. Gel permeation chromatography was used to fractionate and isolate phytochemicals for characterization of …

Correlation Between Texture, Anisotropy, And Vector Magnetization Processes Investigated By Two-Dimensional Vector Vibrating Sample Magnetometry In Bao(Fe₂O₃)₆ Thin Film, Paul Ohodnicki, K. Goh, Michael Mchenry, Katherine Ziemer, Zhaohui Chen, C. Vittoria, Vincent Harris (1962-)

Vincent G. Harris

High ferromagnetic resonance frequencies and low linewidths in BaO(Fe₂O₃)₆ thin films are achieved by obtaining a low-dispersion of crystallite easy c axes normal to the film. X-ray diffraction and magnetic force microscopy are used to characterize texture and magnetic domain structure for a BaO(Fe₂O₃)₆ film deposited on (0001) SiC with a MgO (111) template layer. Strong c-axis texture normal to the film is observed resulting in strong uniaxial anisotropy. The consequent vector magnetization processes due to a combination of domain wall motion and magnetization rotation are characterized by two dimensional vector coil vibrating sample magnetometry (VVSM).

Ba-Hexaferrite Films For Next Generation Microwave Devices, Vincent Harris (1962-), Zhaohui Chen, Yajie Chen, Soack Yoon, Tomokuza Sakai, Anton Geiler, Aria Yang, Yongxue He, Katherine Ziemer, Nian Sun, C. Vittoria

Vincent G. Harris

Next generation magnetic microwave devices require ferrite films to be thick (>300 μm), self-biased (high remanent magnetization), and low loss in the microwave and millimeter wave bands. Here we examine recent advances in the processing of thick Ba-hexaferrite (M-type) films using pulsed laser deposition (PLD), liquid-phase epitaxy, and screen printing. These techniques are compared and contrasted as to their suitability for microwave materials processing and industrial production. Recent advances include the PLD growth of BaM on wide-band-gap semiconductor substrates and the development of thick, self-biased, low-loss BaM films by screen printing.

High-Speed Friction Measurements Using A Modified Surface Forces Apparatus, Younjin Min

Younjin Min

Methods of measuring friction forces in the surface forces apparatus (SFA) are presented for sliding velocities from <1 nm/s to >10 m/s. A feed-forward control (FFC) system for the piezoelectric bimorph slider attachment is introduced to allow experiments at velocities up to ~4 mm/s. For still higher speeds, a motor-driven rotating mini-disk setup using a pin-on-disk geometry is presented, with modifications to enable sliding velocities in the ranges 1 cm/s–5 m/s and 1–25 m/s. Example data sets demonstrate the applicability of the approach to modeling important tribological systems including hard-disk drives. We find that mechanical system parameters such as the resonant frequencies and …

Engineering Instructional Development: Programs, Best Practices, And Recommendations, Michael Prince, R. Felder, R. Brent

Michael J. Prince

No abstract provided.