High Resolution Pure Rotational Raman spectra of Benzene in the Ground State

Department of ChemistryWe used mass-Correlated Rotational Alignment SpectroscopY (mass-CRASY) and obtained pure rotational Raman spectra for benzene in a broad spectral bandwidth of 500 GHz. The rotational spectra were calibrated against a GPS stabilized clock. With a combined optomechanical and electronical delay and randomly sparse sampling, we achieved single MHz resolution for frequency domain spectra of benzene in the ground state. A ground state rotational constant, ????0 = 5689.2671(52) MHz and centrifugal distortion constants ???????? = 1178 (50) Hz and ???????????? = -2300(120) Hz were obtained in 1 MHz resolution spectrum. 1 MHz resolution pure rotational Raman benzene spectrum partially resolved K-structures in two bands. The partially resolved K structure in 1 MHz resolution gave us ideas on the J, K quantum numbers and centrifugal distortion constants for benzene, degeneracy due to molecular symmetry. We reconsider the discrepancies between literature data and our works, and various discussed uncertainties and error sources in different spectroscopic methods.ope

Development of micropump for microfluidic applications

This dissertation covers the research work on two types of micropumps, one is based on magnetohydrodynamic (MHD) principle that utilizes Lorentz force for actuation, and the other is based on electrochemical actuation. The AC-type MHD micropump was designed and analyzed as a solution to the bubble formation problem encountered in DC-type MHD micropump. A UV-LIGA process using thick layer of SU-8 negative photoresist was successfully developed to microfabricate the AC MHD micropump. Preliminary studies and tests of the AC MHD micropumps demonstrate that bubble formation was significantly reduced to permit the proper function of the micropump. A continuous flow was also successfully demonstrated with no moving mechanical parts needed. To develop the mathematical model for flow of conductive fluids between the electrodes was a challenging issue. To overcome this problem, the impedance of conductive fluids between two electrodes was measured by Electrochemical Impedance Spectroscopy, which then helped to obtain a relatively accurate mathematical model for the system. The design, simulation, fabrication, and test results of the AC MHD micropump are presented in this dissertation. Electrochemical actuator was investigated for micropumping applications. In our research efforts to develop DC-type MHD micropump, bubble formation problem caused by electrolysis proved to be one of the most difficult issues. However, microactuation based on expanding bubbles from electrolysis effect has scale advantages compared with other commonly used microactuation mechanisms. It can therefore be used as a very efficient actuation source for micropumping applications. We have designed, analyzed, and fabricated a microactuator based on the electrochemical principle. Preliminary experiments have proved that the bubbles generated in electrolysis can be manipulated by carefully controlling the direction and amplitude of the input signal. This has demonstrated that efficient pumping at micro volume of fluid can be realized by addition of required valves. The microfluidic system with micropump and integrated active microvalve has been successfully demonstrated. The working principle, design, simulation, and preliminary results of the electrochemical actuator have also been presented in the dissertation

Quality Characteristics of Irradiated Turkey Breast Rolls Formulated with Plum Extract

The effects of adding 1%, 2% and 3% plum extract on the quality characteristics of vacuum-packaged, irradiated RTE turkey breast rolls were determined. Turkey breast rolls were sliced, packaged and irradiated at 0 or 3 kGy using a Linear Accelerator. Lipid oxidation, volatile profiles, color, texture, proximate analysis and sensory characteristics of sliced turkey breast rolls were determined at 0 and 7 days of storage. Addition of plum extract had no detectable effect on the proximate analysis of turkey breast rolls. Plum extract increased a* and b*- values, and decreased L* value of turkey breast rolls due to the original color of plum extract. Addition of \u3e2% plum extract to turkey breast rolls was effective in controlling lipid oxidation of irradiated meat and the production of aldehydes (hexanal, heptanal, octanal, and nonanal) in nonirradiated meat at Day 0. Texture of turkey breast rolls was not influenced, but juiciness was increased by plum extract. Therefore, addition of 3% or higher of plum extract is recommended to improve mouth-feel and antioxidant effect in irradiated turkey breast rolls. However, the color of turkey breast rolls with 3% plum extract was dark and might not be appealing to consumers

Fabrication and tuning of plasmonic optical nanoantennas around droplet epitaxy quantum dots by cathodoluminescence

We use cathodoluminescence to locate droplet epitaxy quantum dots with a precision $\lesssim$ nm before fabricating nanoantennas in their vicinity by electron-beam lithography. Cathodoluminescence is further used to evidence the effect of the antennas as a function of their length on the light emitted by the dot. Experimental results are in good agreement with numerical simulations of the structures

Subseasonal convection variability over the Intra-American Seas simulated by an AGCM and sensitivity to CMIP5 SST biases and projections

The influence of coupled model sea surface temperature (SST) climatological biases and SST projections on daily convection over the Intra-American Seas (IAS) during the May–November rainy season are examined by clustering (k − means) daily OLR anomalies in ECHAM5 atmospheric global climate model (AGCM) experiments. The AGCM is first forced by 1980–2005 observed SSTs (GOGA), then with climatological, multi-model mean monthly climato- logical SST bias from 31 CMIP5 coupled models (HIST) and projected SST changes for 2040–2059 (PROJ) and 2080–2099 (PROJ2) imposed on top of observed values. A typology of seven recurrent convection regimes is identified and consists of three dry and four wet regimes, including three regimes charac- terized by tropical-midlatitude interactions between surface convection cells across the IAS and Rossby wave in the upper-troposphere, and a regime of broad wettening typical of the ITCZ. Compared to an earlier observational study, all seven regimes are reasonably well reproduced in the HIST runs. However, the latter exhibit drier dry regimes, a less wet ITCZ-like wet regime and a southeastward shift of convective anomalies developing across the IAS in the three other regimes, all result in a drier simulated IAS climate compared to GOGA. ECHAM5 projection runs for PROJ and PROJ2 are both character- ized by the inhibition of the broad ITCZ-like wet regime, indicating a signifi- cant trend towards more frequent dry weather. Meanwhile, convection anomalies related to tropical-midlatitude interactions are shifted further east of the Caribbean as lead increases. These results suggest more frequent and intense extreme rainfall over the tropical Atlantic and the southeast US, while parts of the Caribbean are projected to experience drier climate. The projected drying, however, is of the same order of magnitude as results from historical SST biases, suggesting that the latter need to be considered in model projec- tions, which might underestimate future IAS drying