Growth and characterization of NLO based L-arginine maleate dihydrate single crystal.
Single crystals of L-arginine maleate dihydrate (LAMD) were successfully grown from aqueous solution by solvent evaporation technique. As-grown crystals were analyzed by different instrumentation techniques such as X-ray powder diffraction (XRD), Fourier transform infrared (FTIR) spectra and UV-vis near infrared (NIR) transmittance spectra. Thermal behavior has been studied with TGA/DTA analyses. The optical second harmonic generation (SHG) conversion efficiency of LAMD was determined using Kurtz powder technique and found to be 1.5 times that of KDP.
Synthesis, growth and characterization of amino acid based semiorganic crystal bis-thiourea l-lysine monohydrochloride
Background: We report on synthesis, growth and characterization of Bis-thiourea L-lysine monohydrochloride (BTLM) crystal. Methods: Bis-thiourea L-lysine momohydrochloride (BTLM) crystal were grown by solution growth method in the molar ratio 1:1 at room temperature. Results: Transparent and defect free crystal of BTLM were harvested in the period of 40-45 days with dimension 7mm × 4mm × 2mm. Single crystal XRD analysis revealed that the crystal system belongs to Orthorhombic with cell parameters a= 14.41 A, b= 5.89 A and c= 15.52 A. The sharp and well defined Bragg peaks observed in the powder XRD pattern confirm the crystalline nature of BTLM crystal. The presences of functional groups in the grown crystal BTLM were identified by FT-IR analysis. The fluorescence spectral study was carried out in the range of 280–500 nm. Second harmonic generation (SHG) of powdered BTLM sample was tested using Nd: YAG laser and is found to be 0.55 times that of potassium dihydrogen orthophosphate. The mechanical strength of the BTLM crystal was evaluated and it describes that the Vickers hardness number of BTLM is found to be increase with the applied load. The work hardening co-efficient (n) has been calculated from the slope of straight line between log P and log d. The dielectric study of BTLM was carried out as a function of frequency at different temperature. Conclusions: From the result we confirm that the BTLM crystals have good physicochemical properties. So, the grown BTLM crystal was suitable candidate for nonlinear optical applications.
Full-scale measurements of SO2 gas phase concentrations and slurry compositions in a wet flue gas desulphurisation spray absorber
Abstract Two measurement campaigns were carried out at ENERGI E2's Asnaes Power plant, unit 5. The unit has a capacity of 620 MW e and is equipped with a wet flue gas desulphurisation (FGD) plant employing a counter-current spray absorber with five spray levels. In the first campaign, the power plant was firing Orimulsion ® with 2.85 wt% S resulting in a flue gas concentration of SO 2 exceeding 2000 ppmv. In the second campaign, the fuel applied was a low-S blended coal and the SO 2 concentration in the raw gas was around 400 ppmv. A novel probe for in situ sampling of gas phase concentrations in wet FGD spray absorbers was developed and applied for measuring axial profiles of the SO 2 gas phase concentrations in the absorber. The expected decrease in SO 2 concentrations along the height of the absorber was found in the spray section (from height 26.5 to 36.2 m) whereas the SO 2 concentration above the holding tank and below the gas inlet was quite low probably due to long local residence times in the region. Horizontal variations, due to somewhat different flow conditions near the column wall were investigated and the SO 2 concentrations were found to be higher near the wall. Measurements at different gross loads showed that the SO 2 gas phase concentration at a given position inside the absorber was roughly linearly related to the L/G ratio in the measuring interval. Turning off one of the lower spray levels, while burning coal with low S content, did not lower the overall removal efficiency of the absorber. However, the SO 2 gas phase concentration inside the lower part of the absorber was increased by a factor of 2–3. Measurements of slurry pH at different positions showed a decrease of approximately 0.5 units from the upper to the lower part of the absorber. The full-scale measurements provide a detailed set of experimental data for validation of mathematical models of a wet FGD spray absorber.