316 research outputs found

    Hydrogen-rich Syngas Production from Ethanol Dry Reforming on La-doped Ni/Al2O3 Catalysts: Effect of Promoter Loading

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    Ethanol dry reforming has been studied over La-promoted Ni catalysts supported on Al2O3 with different promoter loadings at varying CO2 partial pressure of 20-50 kPa. Catalysts were prepared via co-impregnation technique and characterized using BET surface area, X-ray diffraction measurement, temperature-programmed calcination and scanning electron microscopy. Doped and undoped catalysts possessed high surface area of about 86-108 m2 g-1 and La promoter was well-dispersed on support surface. Xray diffraction measurements indicated the formation of La2O3, NiO and NiAl2O4 phases in line with temperature-programmed calcination results. La-addition enhanced the dispersion of NiO particles and reduced the agglomeration of metal oxides. Both C2H5OH and CO2 conversions improved with increasing CO2 partial pressure rationally due to the growing secondary CO2 reforming of CH4 reaction. The ratio of H2/CO produced from ethanol dry reforming varied from 1.1 to 1.4 favored for usage as feedstocks of Fischer-Tropsch synthesis. The yield of H2 and CO also enhanced with increasing CO2 partial pressure whilst the optimal La loading in terms of C2H5OH conversion was observed at 3%La and catalytic activity increased with promoter addition reasonably owing to the redox properties of La promoter. CO2 reforming of ethanol reaction appeared via ethanol decomposition to CH4 intermediate product, which was subsequently converted to CO and H2 mixture through CH4 dry reforming reaction

    Quantum key distribution in terms of the Greenberger-Horne-Zeilinger state: multi-key generation

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    In this paper, we develop a quantum key distribution protocol based on the Greenberger-Horne-Zeilinger states (GHZs). The particles are exchanged among the users in blocks through two steps. In this protocol, for three-particle GHZs three keys can be simultaneously generated. The advantage of this is that the users can select the most suitable key for communication. The protocol can be generalized to NN users to provide NN keys. The protocol has two levels for checking the eavesdroppers. Moreover, we discuss the security of the protocol against different attacks.Comment: 10 Page, no figures. Comments are most welcom

    The effect of twisted magnetic field on the resonant absorption of MHD waves in coronal loops

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    The standing quasi modes in a cylindrical incompressible flux tube with magnetic twist that undergoes a radial density structuring is considered in ideal magnetohydrodynamics (MHD). The radial structuring is assumed to be a linearly varying density profile. Using the relevant connection formulae, the dispersion relation for the MHD waves is derived and solved numerically to obtain both the frequencies and damping rates of the fundamental and first-overtone modes of both the kink (m=1) and fluting (m=2,3) waves. It was found that a magnetic twist will increase the frequencies, damping rates and the ratio of the oscillation frequency to the damping rate of these modes. The period ratio P_1/P_2 of the fundamental and its first-overtone surface waves for kink (m=1) and fluting (m=2,3) modes is lower than 2 (the value for an untwisted loop) in the presence of twisted magnetic field. For the kink modes, particularly, the magnetic twists B_{\phi}/B_z=0.0065 and 0.0255 can achieve deviations from 2 of the same order of magnitude as in the observations. Furthermore, for the fundamental kink body waves, the frequency bandwidth increases with increasing the magnetic twist.Comment: 18 pages, 9 figure

    Friction and wear phenomena of vegetable oil based lubricants with additives at severe sliding wear conditions

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    The tribological responses of palm oil and soybean oil, combined with two commercial antiwear additives (zinc dialkyl dithiophosphate and boron compound), were investigated at a lubricant temperature of 100 °C and under severe contact conditions in a reciprocating sliding contact. The friction coefficient of palm oil with zinc dialkyl dithiophosphate was closest to the commercial mineral engine oil, with a 2% difference. The soybean oil with zinc dialkyl dithiophosphate produced a 57% improvement in wear resistance compared to its pure oil state. The existence of boron nitride in vegetable oils was only responsive in reduction of wear rather than friction. The response of commercial antiwear additives with vegetable oils showed a potential for the future improvement in the performance of vegetable oils

    Negative HER2/neu amplification using immunohistochemistry and chromogenic in situ hybridization techniques in skin melanoma cases

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    Background: This study was performed to evaluate the amplification of HER-2/neu in patients with melanoma. Materials and Methods: Amplification of HER-2/neu was evaluated in a group of patients with melanoma, referred to two referral centers in Tehran, using immunohistochemistry (IHC) and chromogenic in situ hybridization (CISH) techniques. Results: Forty patients with mean age 57.9±19.5 years were enrolled in this study. The most frequent type of melanoma was acral, while lower limbs were the most frequent sites. The amplification of HER2/ neu was negative in 97.5 of patients with IHC and in 100 of patients with CISH technique. Only one case (2.5) shows weak positive staining (+2) in IHC method. Fifty five percent of melanoma was ulcerative, and the most common stages of tumors were stages 4b and 3b. More than 47 of cases were in Clark level III, while the mean of Breslow thickness was 3.56±2.87 mm. The stage of the case that showed weakly positive staining (2+) in IHC was 4b. Conclusions: The amplification of HER2/neu biomarker was negative in patients with melanoma, using both CISH and IHC techniques

    Preferensi Masyarakat Kecamatan Dau Kabupaten Malang dalam Memilih Pola Pelunasan SPPT PBB

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    Tujuan dari artikel ini adalah untuk mengetahui preferensi masyarakat Kecamatan Dau Kabupaten Malang dalam memilih pola pelunasan SPPT pajak bumi dan bangunan di masyarakat Kecamatan Dau Kabupaten Bangkalan dalam memilih pola pelunasan SPPT Pajak Bumi dan Bangunan. Penelitian ini juga mendiskusikan tentang peran pemerintah dalam melakukan diseminasi informasi tentang pelunasan wajak. Metode penelitian ini adalah survei. Hasilnya ternyata ada hubungan antara sosialisasi yang dilakukan pemerintah dengan tingkat pengetahuan dan pemahaman masyarakat dalam membayar pajak

    Artificial neural network model and fuzzy logic control of dissolved oxygen in a bioreactor

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    In a fermentation process, dissolved oxygen is the one of the key process variables that needs to be controlled because of the effect they have on the product quality. In a penicillin production, dissolved oxygen concentration influenced biomass concentration. In this paper, multilayer perceptron neural network (MLP) and Radial Basis Function (RBF) neural network is used in modeling penicillin fermentation process. Process data from an industrial scale fed-batch bioreactor is used in developing the models with dissolved oxygen and penicillin concentration as the outputs. RBF neural network model gives better accuracy than MLP neural network. The model is further used in fuzzy logic controller design to simulate control of dissolved oxygen by manipulation of aeration rate.  Simulation result shows that the fuzzy logic controller can control the dissolved oxygen based on the given profile
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