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The extremely increasing amount of plastic waste due to the development of human society, economics and urbanization is an emergency task that must be urgently handled in order to reduce environmental problems. Although the plastic wastes can be converted to alternative liquid fuels through pyrolysis process, the compositions in the pyrolysis oil depended on the chemical structure of raw materials and pyrolysis condition affect its quality. Thus, this research aimed to comparatively investigate the production of alternative liquid fuels obtained from mixed plastics containing polystyrene (PS)/polyethylene terephthalate (PET)/polyethylene (PE)/polypropylene (PP) at 20/5/35/40 (w/w) via non-catalytic cracking (under N2 atmosphere), non-catalytic hydrocracking (under H2 atmosphere), and catalytic hydrocracking over 10 wt% Ni/SBA-15 catalyst conducted at an atmospheric pressure and 650 °C for 1 h. The product yields and chemical compositions (paraffins, olefins, aromatics and PAHs) in the liquid products generated from these processes were investigated and also compared to ones obtained from the non-catalytic processes of each plastic. Herein, the characteristics of 10 wt% Ni/SBA-15 catalyst was analyzed by N2-adsorption/desorption, X-ray diffraction (XRD), and H2-temperature programmed reduction (H2-TPR). The results indicated that the non-catalytic processes of PS provided the highest content of oil and wax product (ca. 92 wt%). Whereas, the non-catalytic hydrocracking of the mixed plastics gave the lowest one (ca. 69 wt%). However, the catalytic hydrocracking over 10 wt% Ni/SBA-15 catalyst (2.5 – 10.0 wt% based on the mixed plastics) could suppress the cracking and yielded the higher amount of oil and wax to ca. 76–80 wt%. To consider the chemical compositions in the liquid phase, the PAHs formation was relied on the aromatic structure in the feedstocks. The liquid product derived from the non-catalytic processes of PS contained the highest amount of PAHs compounds (2622–2926 ppm) followed by the mixed plastics. When the 10 wt% Ni/SBA-15 catalyst was applied to the catalytic hydrocracking of the mixed plastics, the amount of PAHs in the liquid product decreased from 1621 ppm to ca. 1000 ppm (30 – 40% PAHs reduction) without the reduction of heating value when compared to one obtained from the non-catalytic processes.

Gd3+ doped borate glass samples with compositions of xGd2O3-(99-x)B2O3–1Eu2O3; (x = 20, 25, 30 and 35 mol%) (GdBEu) have been synthesized by melt-quenching method at 1400 °C for 3 h. GdBEu glasses characteristics have been determined via FTIR, absorption, emission (X-rays and UV excitation), and CIE color coordinates analysis. The GdBEu glasses presented density increase and molar volume decrease with Gd3+ ions. Ultraviolet (UV) and X-ray excitation have been indicated performance as well as luminescent properties of Gd2O3 doped glass structure. The 5D0 → 7F0 (582 nm), 5D0 → 7F1 (591 nm), 5D0 → 7F2 (616 nm), 5D0 → 7F3 (654 nm) and 5D0 → 7F4 (702 nm) were found at 275 nm and 394 nm excitations. The energy transfer phenomena from Gd3+→ Eu3+ in these glasses were observed. Intense reddish-orange emission were observed at 613 nm, which associated by energy transfer phenomena from Gd3+→ Eu3+ states in these glasses. The phonon sideband (PSB) and pure electronic transition (PET) were measured and calculated ponon energy of glasses. Decay time of GdBEu luminescence decreased with increase of Gd2O3 concentration. The Commission Internationale de l’Elcairage (CIE) color coordinates of GdBEu glasses displayed in reddish-orange region. X-rays induced luminescence presented 12% photon emission of GdBEu glasses comparing with BGO scintillation crystal.

Glasses have a wide variety of applications in different types of devices, including solid-state lasers, fiber-optic amplifiers, medical imaging, radiation dosimeter, solar cells, neutron imaging, and scintillators. Among several rare-earth (RE) ions, Ce3+ exhibits short decay time and offers promising scintillation when it is doped in a transparent glass matrix. The objective of this study was to investigate the energy transfer from Gd3+, La3+, and Y3+ ions to Ce3+ ion in 64.5P2O5:20Li2O:5Al2O3 glass matrix while considering an enhancement in its scintillation efficiency. Four glass samples doped with CeF3 alone and co-doped with GdF3, LaF3, and YF3 were fabricated. Broad photoluminescence and radio-luminescence emissions peaking near to 340 and 350 nm were found when excited by 310 nm and X-ray, respectively, for all the glasses. A photoluminescence emission quenching was found in LaF3 co-doped glass. A strong energy transfer from Gd3+ to Ce3+ was noticed while the GdF3 co-doped glass was excited by X-ray, 275 nm (from Gd3+), and 310 nm (from Ce3+) excitations. The Gd3+ co-doped glass consisted of a 37 ns decay constant under the 266 nm laser excitation. The thermoluminescence analysis showed two glow curves centered at 210 °C and 345 °C, respectively, after X-ray irradiation. Considering the efficient energy transfer from Gd3+ to Ce3+ ions and short lifetime of Ce3+ emission, the glass composition of the above formula having Gd3+ and Li+ with Ce3+ ions appeared to be a promising candidate in the search of good promising scintillating glasses with fast fluorescence decay time.

In this work, Bi2MoO6 and Bi(2-x)DyxMoO6 (x = 0.05, 0.10, 0.15 and 0.20 % by mol) phosphors were synthesized by high- temperature solid-state reaction method. The finely powdered mixtures were sintered at 500, 550, 600, 650 and 700 °C for 12 h in air atmosphere. The structural characteristics of Bi2MoO6 phosphors were examined and confirmed by X-ray diffraction (XRD). The optical spectra were measured and confirmed signature peaks of Dy3+ ions in Bi2MoO6 phosphors. The emission spectra of phosphors exhibited emission bands at 482, 575, 663 and 750 nm corresponding to 6H15/2, 6H13/2, 6H11/2 and 6H9/2 transitions from the ground state (4F9/2). The emission of Bi(2-X)DyXMoO6 (x= 0.10) was shown greendish-yellow color, calculated by CIE 1931 color coordinate.

In this work, the Gd2MoB2O9 and Gd2MoB2O9:Dy3+ phosphors have been prepared by solid state reaction and their structural and luminescence properties have been studied. The Gd2O3, MoO3, H3BO3 and Dy2O3 were used as starting materials and homogeneously mixed with appropriate ratio. The mixed materials were pressed at 20 tons and sintered at 800, 850, 900, 950, 1000, 1050 and 1100°C. The Gd2MoB2O9 phase was confirmed by X-ray diffractometer (XRD). The photoluminescence spectra measured by 257 nm excitation show one emission peak at 310 nm corresponding to 6P7/2→8S7/2 of Gd3+, and four emission peaks of Dy3+ at 478, 575, 663 and 754 nm corresponding to 4F9/2 → 6H15/2, 6H13/2, 6H11/2 and 6H9/2 transitions, respectively. The chromaticity coordinates under excitation of λex = 352 nm are (0.48, 0.42), which lies in the white region of CIE 1931 chromaticity diagram. The radioluminescence property was studied by 50 kV, 30 mA X-ray irradiation and compared with commercial BGO crystal. It was found that the i...

Industrial plaster waste (PW) which consists of high majority SiO2 as a source was used to fabricate glass. A novel glass containing 30PW-(64.5- x) B2O3- xNa2O-0.5Sm2O3(where x = 5, 10, 15, 20 mol%) and 30PW-(40-x) B2O3–30Na2O- x Sm2O3 (0≤ x ≤ 1.5 mol%) has fabricated using industrial plaster waste as silica source doped with Sm3+ ions and studied their optical behavior for solid state lighting applications by subjecting the glasses to several spectroscopic measurements and applying the well-known Judd-Ofelt theory to bring out their significance in the field of optical devices. Optical absorption spectra were recorded and investigated for the signature of Sm3+ ions. Judd-Ofelt parameters show Ω4>Ω6>Ω2 for (5 mol% Na2O) low alkali content glass and Ω2>Ω4>Ω6 for (30 mol% Na2O) high alkali content glass. Photoluminescence of low alkali content in the Sm3+ ions doped glass show blue shift in their peak position than compared to rich alkali content in the Sm3+ ions doped glass. Radiative properties were evaluated using JO parameters. Stimulated emission cross-section shows higher value for rich alkali content than low alkali content and also compared with other glasses. The energy transfer parameter for N1 glass is lower than F4 glass and both these glasses showed quadrupole-quadrupole interaction between Sm3+ ions. R0 (critical distance) of donor Sm3+ ions-acceptor Sm3+ ions separation for 30PW-64.5B2O3–5Na2O-0.5Sm2O3 (N1) is larger than 30PW-39.5B2O3–30Na2O-0.5Sm2O3 (F4) glass. Lifetime analysis, Commission International de L'Eclairage (CIE) chromaticity diagram and correlated color temperature (CCT) values were evaluated. From the data obtained from the investigations, we conclude that the industrial plaster waste could be used for manufacturing glasses which are useful to solid state lighting device applications.

A graft copolymer of acrylonitrile (ACN) and styrene (ST) on natural rubber (NR) was prepared by solution polymerization initiated by benzoyl peroxide. The effect of graft NR (GNR) applied as a compatibilizer for NR/nitrile rubber (NBR) blends on their mechanical and physical properties was investigated. The results revealed that the tensile properties and oil-swelling resistance of the blends increased with increasing %graft copolymer of GNR. The tensile fracture surfaces of the compatibilized NR/NBR vulcanizates attested by scanning electron microscopy indicated the improvement of interfacial adhesion between two rubber phases. Moreover, the dynamic mechanical properties of compatibilized vulcanizates were also reported.

Journal of Thai Interdisciplinary Research, Vol.12, No.5