The Experts below are selected from a list of 163422 Experts worldwide ranked by ideXlab platform
Raphael Idem - One of the best experts on this subject based on the ideXlab platform.
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effect of alkanol chain length of primary alkanolamines and alkyl chain length of secondary and tertiary alkanolamines on their co2 capture activities
Separation and Purification Technology, 2017Co-Authors: Jessica Narkutetteh, Pailin Muchan, Raphael IdemAbstract:Abstract The effect of the alkanol chain length in primary alkanolamines and the alkyl chain length in secondary and tertiary alkanolamines on CO 2 Absorption and desorption kinetics, equilibrium CO 2 loading, heat duty, cyclic capacity, and pKa were studied. A selection strategy developed in our earlier work was used to identify potential solvents which could be used in a blend. Based on the strategy, alkanolamines that had a combination of high Absorption parameter and high desorption parameter should be selected. The results of this study showed that, for Absorption Parameters, longer alkanol chain lengths of primary alkanolamines and longer alkyl chain lengths of secondary and tertiary alkanolamines led to higher equilibrium CO 2 loading and pKa. However, the influence of mass transfer limitations on these positive effects resulted in a maximum trend for initial rate of CO 2 Absorption for secondary and tertiary alkanolamines. On the other hand, for the desorption Parameters, the increase in the chain lengths also caused the generation of larger amounts of bicarbonate ions which resulted in higher CO 2 desorption rates and cyclic capacity, but lower heat duty. However, the longer chain alkanolamines also had high viscosities which adversely modified their performance by also introducing mass transfer limitations. Based on chain length alone, BMEA came out as the best overall alkanolamine component which could be used in a blend.
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analysis of co2 solubility and Absorption heat into 1 dimethylamino 2 propanol solution
Chemical Engineering Science, 2017Co-Authors: Raphael Idem, Helei Liu, Hongxia Gao, Paitoon Tontiwachwuthikul, Zhiwu LiangAbstract:Abstract In this work, the CO2 equilibrium solubility in 1-dimethylamino-2-propanol (1DMA2P) solution was determined as a function of 1DMA2P concentration (over the range of 1–5 M), temperature (in the range of 298–333 K), and CO2 partial pressure (in the range of 8–101 kPa), and the data used to fit the correlations for K2 using Kent-Eisenberg, Austgen, Li-Sheng and Hu-Chakma models. A new K2 correlation model was also developed to predict the CO2 equilibrium solubility in 1DMA2P solution. It was found that all of the models could fit the CO2 equilibrium solubility in 1DMA2P solution data with absolute average deviations (ADDs) for the models by Kent-Eisenberg, Austgen, Li-Sheng, Hu-Chakma and Liu et al. of 14, 15, 12, 6.3 and 10%, respectively. In addition, the heat of CO2 Absorption in 1DMA2P solution estimated using Gibbs-Helmholtz equation was found to be −31.67 kJ/mol. Information or guidelines about effective utilization of data of screened solvents is provided based on three Absorption Parameters, namely, CO2 equilibrium solubility, second order reaction constant, and CO2 Absorption heat.
Teruyuki Nakajima - One of the best experts on this subject based on the ideXlab platform.
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a k distribution based radiation code and its computational optimization for an atmospheric general circulation model
Journal of Quantitative Spectroscopy & Radiative Transfer, 2008Co-Authors: Miho Sekiguchi, Teruyuki NakajimaAbstract:Abstract The gas Absorption process scheme in the broadband radiative transfer code “mstrn8”, which is used to calculate atmospheric radiative transfer efficiently in a general circulation model, is improved. Three major improvements are made. The first is an update of the database of line Absorption Parameters and the continuum Absorption model. The second is a change to the definition of the selection rule for gas Absorption used to choose which Absorption bands to include. The last is an upgrade of the optimization method used to decrease the number of quadrature points used for numerical integration in the correlated k-distribution approach, thereby realizing higher computational efficiency without losing accuracy. The new radiation package termed “mstrnX” computes radiation fluxes and heating rates with errors less than 0.6 W/m2 and 0.3 K/day, respectively, through the troposphere and the lower stratosphere for any standard AFGL atmospheres. A serious cold bias problem of an atmospheric general circulation model using the ancestor code “mstrn8” is almost solved by the upgrade to “mstrnX”.
H.m. Zeyada - One of the best experts on this subject based on the ideXlab platform.
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Spectroscopic studies of UV irradiated erythrosine B thin films prepared by spin coating technique.
Spectrochimica acta. Part A Molecular and biomolecular spectroscopy, 2017Co-Authors: H.m. Zeyada, T. Atwee, H. M. El-mallah, D. G. El-damhogiAbstract:Abstract The spectroscopic studies of erythrosine B thin films manufactured by the spin coating technique have been presented. The spectra of infrared Absorption allow characterization of vibrational modes for erythrosine B in powder form, pristine and UV irradiated thin films. The Absorption spectra recorded in UV–vis–NIR for pristine films of erythrosine B display two main bands. UV irradiation on erythrosine B films decreased absorbance over the spectra. Indirect allowed transition with optical energy gap of 2.57 eV is observed in pristine films. UV irradiation introduced structural defects and decreased optical band gap. Some of the optical Absorption Parameters and their relation to UV irradiation times, namely molar extinction coefficient ( e ), electronic dipole strength ( q 2 ), and oscillator strength ( f ), of the principal optical transitions have also been evaluated.
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annealing temperatures induced optical constant variations of methyl violet 2b thin films manufactured by the spin coating technique
Journal of Non-crystalline Solids, 2012Co-Authors: H.m. Zeyada, M M Elnahass, I S Elashmawi, A A HabashiAbstract:Abstract Spin coating technique has been successfully applied to deposit uniform methyl violet 2B (MV2B) thin films. X-ray diffraction and Fourier-transform infrared techniques were used to study the crystal and molecular structure of MV2B. The optical properties of the films have been studied by spectrophotometer measurements of transmittance and reflectance at normal incidence of light in the spectral range of 200–2500 nm. The Absorption and refractive indices are independent of the film thickness. The Absorption Parameters such as molar extinction coefficient, oscillator strength and electric dipole strength have been reported before and after annealing. The type of electronic transition is indirect allowed transition with onset energy gap of 1.82 eV and optical energy gap of 3.65 eV. Annealing temperatures reduce structure disorder, remove trap level, increase values of the onset and optical energy gaps and decrease refractive index. The single oscillator model has been applied for calculating the dispersion Parameters. The oscillator energy, the dispersion energy, the high frequency dielectric constant, the lattice dielectric constant and the ratio of free charge carriers' concentration to its effective mass were evaluated before and after annealing. The dielectric properties of the films were also determined.
M M Elnahass - One of the best experts on this subject based on the ideXlab platform.
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structural and optical properties of nanocrystalline platinum octaethylporphyrin ptoep thin films
Journal of Alloys and Compounds, 2016Co-Authors: A A Abuelwafa, A Eldenglawey, M Dongol, M M Elnahass, Tetsuo SogaAbstract:Abstract Thermal evaporation technique was used to prepare the Platinum octaethylporphyrin (PtOEP) thin films. X-Ray Diffraction (XRD), Transmission Electron Microscope (TEM) and Fourier-transform infrared techniques (FT-IR) were used to study the crystal and molecular structure of PtOEP, the results confirmed that the PtOEP thin films have nonostructural features. Extinction coefficient, k and refractive index, n were estimated using spectrophotometric measurements of both transmittance T (λ) and reflectance R (λ) at normal incidence light in the wavelength range 200–1100 nm. The Absorption Parameters such as molar extinction coefficient, e molar , oscillator strength, ƒ and electric dipole strength, q2, the type of electronic transition, optical energy gap and fundamental energy gaps were reported. The normal dispersion (λ > 600 nm) of refractive index is discussed in terms of single oscillator model of Wemple–Didomenico. The dispersion and the dielectric characterizations of the thin films were investigated and discussed.
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structural and optical properties of nanocrystalline aluminum phthalocyanine chloride thin films
Materials Science in Semiconductor Processing, 2015Co-Authors: M M Elnahass, H S Soliman, B A Khalifa, I M SolimanAbstract:Abstract Thin films of aluminum phthalocyanine chloride (AlPcCl) were fabricated, with different thicknesses (109–518 nm) using thermal evaporation technique. Structural and optical properties of AlPcCl thin films were investigated. The material in powder form showed a polycrystalline nature with monoclinic structure. Miller indices, hkl, values for each diffraction line in X-ray diffraction (XRD) spectrum were calculated. The field emission scanning electron microscope (FESEM) showed the nanostructure property of the as-deposited thin films. The optical properties of the thin films were studied by the spectrophotometric measurements of the transmittance, T, and the reflectance, R, at the normal incidence of the light in the spectral range 200–2500 nm. The refractive and Absorption indices of the thin films were calculated and were found to be independent of film thickness of 109–518 nm. The films exhibited indirect allowed inter-band transitions. The optical band gaps transitions were calculated as 1.42, 2.87 and 3.69 eV, respectively. Also, different dispersion and Absorption Parameters were determined for thin films of AlPcCl.
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annealing temperatures induced optical constant variations of methyl violet 2b thin films manufactured by the spin coating technique
Journal of Non-crystalline Solids, 2012Co-Authors: H.m. Zeyada, M M Elnahass, I S Elashmawi, A A HabashiAbstract:Abstract Spin coating technique has been successfully applied to deposit uniform methyl violet 2B (MV2B) thin films. X-ray diffraction and Fourier-transform infrared techniques were used to study the crystal and molecular structure of MV2B. The optical properties of the films have been studied by spectrophotometer measurements of transmittance and reflectance at normal incidence of light in the spectral range of 200–2500 nm. The Absorption and refractive indices are independent of the film thickness. The Absorption Parameters such as molar extinction coefficient, oscillator strength and electric dipole strength have been reported before and after annealing. The type of electronic transition is indirect allowed transition with onset energy gap of 1.82 eV and optical energy gap of 3.65 eV. Annealing temperatures reduce structure disorder, remove trap level, increase values of the onset and optical energy gaps and decrease refractive index. The single oscillator model has been applied for calculating the dispersion Parameters. The oscillator energy, the dispersion energy, the high frequency dielectric constant, the lattice dielectric constant and the ratio of free charge carriers' concentration to its effective mass were evaluated before and after annealing. The dielectric properties of the films were also determined.
D. G. El-damhogi - One of the best experts on this subject based on the ideXlab platform.
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Spectroscopic studies of UV irradiated erythrosine B thin films prepared by spin coating technique.
Spectrochimica acta. Part A Molecular and biomolecular spectroscopy, 2017Co-Authors: H.m. Zeyada, T. Atwee, H. M. El-mallah, D. G. El-damhogiAbstract:Abstract The spectroscopic studies of erythrosine B thin films manufactured by the spin coating technique have been presented. The spectra of infrared Absorption allow characterization of vibrational modes for erythrosine B in powder form, pristine and UV irradiated thin films. The Absorption spectra recorded in UV–vis–NIR for pristine films of erythrosine B display two main bands. UV irradiation on erythrosine B films decreased absorbance over the spectra. Indirect allowed transition with optical energy gap of 2.57 eV is observed in pristine films. UV irradiation introduced structural defects and decreased optical band gap. Some of the optical Absorption Parameters and their relation to UV irradiation times, namely molar extinction coefficient ( e ), electronic dipole strength ( q 2 ), and oscillator strength ( f ), of the principal optical transitions have also been evaluated.
