Transmission in irradiated hydroxyethyl methacrylate copolymer at elevated temperatures

2002 ◽  
Vol 17 (9) ◽  
pp. 2260-2265 ◽  
Author(s):  
K-P. Lu ◽  
Sanboh Lee ◽  
C. C. Han
Keyword(s):  
Elevated Temperatures ◽  
Wave Length ◽  
Color Centers ◽  
Order Kinetic ◽  
Hydroxyethyl Methacrylate ◽  
Absorption Data ◽  
Visible Spectra ◽  
Transmission Data ◽  
Methacrylate Copolymer ◽  
Good Agreement

Transmission losses were monitored in the ultraviolet-visible spectra of irradiated hydroxyethyl methacrylate (HEMA) copolymer at elevated temperatures. The transmission in irradiated HEMA in the ultraviolet and visible wave length range was almost the same for doses 400 kGy ≤ Φ ≤ 1000 kGy, but was smaller than that of the nonirradiated HEMA copolymer. The reduction in transmission in the irradiated specimens was attributed to the presence of color centers. The concentration of color centers was enhanced by thermal annealing. The transmission data (or absorption data) at 467 nm was found in good agreement with the theoretical model in which the color center production followed a first-order kinetic process. The rate constant satisfies the Arrhenius equation, and the corresponding activation energy is 17.37 kJ/mol and is independent of the dosage. The results were compared with those reported in the literature.

SYNTHESIS AND SPECTROSCOPY OF SOME QUATERNARY OXYFLUORIDE GLASSES DOPPED WITH COPPER

2013 ◽  
Vol 22 ◽  
pp. 284-291 ◽  
Author(s):  
CH. SRINIVASU ◽  
M. A. SAMI ◽  
A. EDUKONDALU ◽  
SYED RAHMAN
Keyword(s):  
Optical Absorption ◽  
Absorption Spectra ◽  
Copper Ions ◽  
Wave Length ◽  
Broad Band ◽  
Spin Hamiltonian Parameter ◽  
Band Gap Energy ◽  
Site Symmetry ◽  
Optical Absorption Spectra ◽  
Absorption Data

Electron paramagnetic resonance (EPR) and optical absorption spectra of copper ions in xLiF-(50-x)Li2O-20SrO-30Bi2O3 glass system have been studied. MDSC studies showed that the glass transition temperature decreases with LiF content. Optical absorption spectra of the pure glasses reveled that the cut off wave length increased and optical band gap energy decreased with increase in LiF content. EPR spectra of all the glass samples exhibit resonance signals characteristic of Cu2+ ions. The Cu2+ ions are in well-defined axial sites but subjected to small distortion leading to the broadening of the spectra. The spin-Hamiltonian parameter values indicate that the ground state of Cu2+ is d x2 y2 and the site symmetry around Cu2+ ions is tetragonally distorted octahedral. The optical absorption spectra exhibited a broad band corresponding to the d-d transition bands of Cu2+ ion. By correlating EPR and optical absorption data, the bond parameters are evaluated from various techniques.

The continuous absorption of light in alkali-metal vapours

1953 ◽  
Vol 219 (1136) ◽  
pp. 89-101 ◽  
Keyword(s):  
Cross Section ◽  
Alkali Metals ◽  
Theoretical Calculations ◽  
Wave Length ◽  
Energy Difference ◽  
Continuous Absorption ◽  
Absorption Of Light ◽  
Sodium Vapour ◽  
Good Agreement ◽  
Dipole Length

The first section of this paper is an account of some experiments on the absorption of light in sodium vapour from the series limit at 2412 Å to about 1600 Å (an energy difference of 2·6 eV). The absorption cross-section at the limit is 11·6 ± 1·2 x 10 -20 cm 2 . The cross-section decreases giving a minimum of 1·3 ± 0·6 x 10 -20 cm 2 at 1900 Å and then increases to 1600 Å. A theoretical calculation by Seaton based on the dipole-length formula gives good agreement with the experiments at the series limit and also correctly predicts the wave-length for the minimum, but it predicts a significantly lower absorption at the minimum. The experiments described in the first section of the paper conclude a series on the absorption of light in the alkali metals. The second section consists of a general discussion of the results of these experiments and of their relation to theoretical calculations. There is good agreement between theory and experiment except in regard to the magnitude of the absorption at the minimum.

scholarly journals Deposition of styrene/2-hydroxyethyl methacrylate copolymer latex onto grafted nylon 6 fiber.

1989 ◽  
Vol 45 (12) ◽  
pp. 523-528
Author(s):  
Masahiko Sasaki ◽  
Nobuaki Matsumoto ◽  
Toshiro Suzawa
Keyword(s):  
Nylon 6 ◽  
Hydroxyethyl Methacrylate ◽  
Methacrylate Copolymer

scholarly journals OPTIMIZATION OF LEVOFLOXACIN REMOVAL FROM AQUEOUS SOLUTION USING ELECTROCOAGULATION PROCESS BY RESPONSE SURFACE METHODOLOGY

2021 ◽  
Vol 52 (1) ◽  
pp. 204-217
Author(s):  
Mohammed & Mohammed-Ridha
Keyword(s):  
Aqueous Solution ◽  
Response Surface Methodology ◽  
Response Surface ◽  
Correlation Coefficient ◽  
Iron Hydroxide ◽  
Second Order ◽  
Experimental Results ◽  
Order Kinetic ◽  
Experimental Conditions ◽  
Good Agreement

This study was aimed to investigate the response surface methodology (RSM) to evaluate the effects of various experimental conditions on the removal of levofloxacin (LVX) from the aqueous solution by means of electrocoagulation (EC) technique with stainless steel electrodes. The EC process was achieved successfully with the efficiency of LVX removal of 90%. The results obtained from the regression analysis, showed that the data of experiential are better fitted to the polynomial model of second-order with the predicted correlation coefficient (pred. R2) of 0.723, adjusted correlation coefficient (Adj. R2) of 0.907 and correlation coefficient values (R2) of 0.952. This shows that the predicted models and experimental values are in good agreement. The results of the kinetic study showed that the second-order kinetic model was in good agreement with the experimental results and suggested that the mechanism of chemisorption controlled the LVX adsorption. The experimental results indicated that the adsorption of LVX on iron hydroxide flocs follows Sips isotherm with the value of the correlation coefficient (R2) of 0.937. Sips isotherm shows that both homogenous and heterogeneous adsorption can occur.

scholarly journals Design, Synthesis, Spectral and Theoretical Studies of Some Picrates

2019 ◽  
Vol 32 (1) ◽  
pp. 174-182
Author(s):  
S. Amala ◽  
G. Rajarajan ◽  
E. Dhineshkumar ◽  
M. Arockia doss ◽  
V. Thanikachalam
Keyword(s):  
Geometrical Parameters ◽  
Slight Effect ◽  
Design Synthesis ◽  
1H And 13C Nmr ◽  
Visible Spectra ◽  
Ft Ir ◽  
Uv Visible ◽  
Small Change ◽  
Experimental Values ◽  
Good Agreement

The structures of newly synthesized compounds (1-3) viz. 3-ethyl-5-methyl-2,6-bis(4- chlorophenyl)piperidin-1-ium picrate (1), 3-ethyl-5-methyl-2,6-bis(4-methylphenyl)piperidin-1-ium picrate (2) and 3-ethyl-5-methyl-2,6-bis(3,4-dimethoxyphenyl)piperidin-1-ium picrate (3) were confirmed by elemental analysis, FT-IR, 1H and 13C NMR. The UV-visible spectra, fluoresence, emission properties of synthesized 1-3 in different solvents were studied. Compounds 1-3 solvatochromic displays a slight effect of the emission and absorption spectrum, indicating a small change in the dipole moment upon excitation of compounds 1-3. All the compounds were investigated by DFT. The theoretical geometrical parameters are in good agreement with experimental values.

scholarly journals Curie Temperature and Microstructural Changes Due to the Heating Treatment of Magnetic Amorphous Materials

2016 ◽  
Vol 61 (1) ◽  
pp. 451-456 ◽  
Author(s):  
J. Gondro ◽  
K. Błoch ◽  
P. Brągiel ◽  
M. Nabiałek ◽  
M. Szota
Keyword(s):  
Amorphous Materials ◽  
Elevated Temperatures ◽  
Great Influence ◽  
Soft Magnetic ◽  
Transmission Electron ◽  
Heisenberg Type ◽  
Heating Treatment ◽  
Magnetic Hardening ◽  
Curie Temperatures ◽  
Good Agreement

Three distinct alloys: Fe86Zr7Nb1Cu1B5, Fe82Zr7Nb2Cu1B8, and Fe81Pt5Zr7Nb1Cu1B5were characterized both magnetically and structurally. The samples, obtained with spinning roller method as a ribbons 3 mm in width and 20 μm thick, were investigated as-quenched and after each step of a multi steps heating treatment procedure. Each sample was annealed at four steps, fifteen minutes at every temperature, starting from 573K+600K up to +700K depending on type of alloy. Mössbauer spectroscopy data and transmission electron microscope (HRE M) pictures confirmed that the as-quenched samples are fully amorphous. This is not changed after the first stages of treatment heating leads to a reduction of free volumes. The heating treatment has a great influence on the magnetic susceptibilities. The treatment up to 600K improves soft magnetic properties: an χ increase was observed, from about 400 to almost 1000 for the samples of alloys without Pt, and from about 200 to 450 at maximum, for the Fe81Pt5Zr7Nb1Cu1B5. Further heating, at more elevated temperatures, leads to magnetic hardening of the samples. Curie temperatures, established from the location of Hopkinson’s maxima on the χ(T) curve are in very good agreement with those obtained from the data of specific magnetization, σ(T), measured in a field of 0.75T. As a critical parameter β was chosen to be equal 0.36 for these calculations, it confirmed that the alloys may be considered as ferromagnetic of Heisenberg type. Heating treatment resulted in decreasing of TC. These changes are within a range of several K.

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