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A parametric comparison study is carried out between segmented and conventional continuous layer configurations of the coated combustion-catalyst to investigate their influence on the performance of methane steam reforming (MSR) for hydrogen production in a catalytic plate reactor (CPR). MSR is simulated on one side of a thin plate over a continuous layer of nickel-alumina catalyst by implementing an experimentally validated surface microkinetic model. Required thermal energy for the MSR reaction is supplied by simulating catalytic methane combustion (CMC) on the opposite side of the plate over segmented and continuous layer of a platinum-alumina catalyst by implementing power law rate model. The simulation results of both coating configurations of the combustion-catalyst are compared using the following parameters: (1) co-flow and counter-flow modes between CMC and MSR, (2) gas hourly space velocity and (3) reforming-catalyst thickness. The study explains why CPR designed with the segmented combustion-catalyst and co-flow mode shows superior performance not only in terms of high hydrogen production but also in terms of minimizing the maximum reactor plate temperature and thermal hot-spots. The study shows that the segmented coating requires 7% to 8% less combustion-side feed flow and 70% less combustion-catalyst to produce the required flow of hydrogen (29.80 mol/h) on the reforming-side to feed a 1 kW fuel-cell compared to the conventional continuous coating of the combustion-catalyst. [ABSTRACT FROM AUTHOR]

The structural and optical properties of trivalent dysprosium (Dy 3+ )-doped zinc– aluminum–sodium–phosphate (ZANP) glasses have been investigated using XRD, FTIR, absorption, emission spectra and decay curve. The XRD profiles and SEM images confirm the glassy nature of the investigated glass samples. FTIR spectra reveal the presence of PO 4 units along with OH − groups in the glasses. The absorption spectra of Dy 3+ showed eight absorption bands with hypersensitive at 1272 nm ( 6 H 15/2 → 6 F 11/2 ) and three PL emission bands at 485 nm ( 4 F 9/2 → 6 H 15/2 ), 576 nm, ( 4 F 9/2 → 6 H 13/2 ) and 665 nm ( 4 F 9/2 → 6 F 11/2 ). The luminescence intensity ratio of 4 F 9/2 → 6 H 13/2 to 4 F 9/2 → 6 H 15/2 transitions of Dy 3+ in ZANP glasses gives feasibility of extracting white light. The experimental branching ratios and stimulated emission cross-sections are higher for 4 F 9/2 → 6 H 13/2 transition. The lifetime of the decay is obtained by taking the first e-folding times of the decay curves and is found to decrease with increase of Dy 3+ ions concentration. The decay curves are found to be perfectly single exponential for samples upto1.5 mol% Dy 3+ ion concentrations. The non-exponential curve is obtained at 2.0 mol% of Dy 3+ ion concentration, which indicates the energy transfer between the donor and acceptor. [ABSTRACT FROM AUTHOR]

Given the recent increased interest in phosphor materials and their applications, we analyzed a new NaPbB 5 O 9 :Dy 3+ phosphor material with different concentrations of Dy 3+ . In particular, we investigated the crystal structure, morphology, and luminescence properties of these materials. X-ray diffraction analyses confirmed the formation of NaPbB 5 O 9 :Dy 3+ phosphor powder. The functional groups present in the phosphor materials were examined by Fourier transform infrared spectroscopy. Scanning electron microscope images showed that the size of the grains was in the micrometer range. Photoluminescence spectra were recorded at different excitation wavelengths for the phosphor materials and we analyzed the variation in the intensity of the emission bands with different concentrations of Dy 3+ ions. The color co-ordinates were calculated and used to characterize the color of the phosphor. We found that the emission colors of the Dy 3+ -doped NaPbB 5 O 9 powders depended on the Dy 3+ ion doping concentration and the excitation wavelength. [ABSTRACT FROM AUTHOR]

Highlights: [•] Zinc-alumino-sodium-phosphate (ZANP) doped with Pr3+ and Nd3+ were synthesized by melt quenching method. [•] Judd–Ofelt parameters Ωλ (λ =2, 4 and 6) calculated and compared with other glass matrices. [•] Finding laser transition in both Pr3+ and Nd3+ doped glass matrices. [ABSTRACT FROM AUTHOR]

Highlights: [•] Judd–Ofelt theory is applied and analyzed the spectra of Nd3+ doped glasses. [•] The radiative properties of all present glasses were calculated. [•] Larger β and higher σem are observed for the Nd3+:4F3/2 →I11/2 laser emission. [•] The η of present glasses are higher than phosphate and germanate glasses. [•] The gain cross sections at ∼0.9μm are estimated by reciprocity method. [ABSTRACT FROM AUTHOR]

Abstract: Strontium lithium bismuth borate glasses (SLBiB) doped with various concentrations of Er3+ were prepared using conventional melt quenching technique and investigated their structural and optical properties. The structural properties were investigated using XRD and FTIR spectra. XRD analysis confirmed amorphous nature of glass samples. FTIR spectra were used to find the functional groups in the glass matrices. Optical properties were studied by measuring the optical absorption and near infrared luminescence spectra. Judd–Ofelt (J–O) theory has been applied to evaluate J–O intensity parameters, Ωλ (λ =2, 4 and 6) and are used to estimate radiative properties like transition probabilities (A), branching ratios (β) and radiative lifetimes (τR ) for certain transitions. Among all transitions, 4I13/2 → 4I15/2 transition shows higher branching ratio as well as higher radiative lifetime values. Peak emission-cross sections (σe ), full-width at half maximum (FWHM) and products of stimulated emission cross-section and full-width at half maximum (σe ×FWHM) were calculated for the observed emission transition, 4I13/2 → 4I15/2. These values are higher for 1.0mol% of Er3+ glass matrix among all glass matrices. Using the Mc-Cumber theory, stimulated emission cross-sections (σe ) were obtained from absorption cross-section (σa ). [Copyright &y& Elsevier]

Highlights: [•] The effect of modifier oxides on J–O intensity parameters and radiative properties are studied. [•] Decay curves of 4F9/2 state exhibits non-exponential nature in all the glasses. [•] Dy3+ doped different modifiers in zinc borate glasses exhibits white light emission under 450nm excitation. [Copyright &y& Elsevier]

Highlight: [•] Power system model for transmission-line fault classification fed from both ends. [•] Fault classification algorithm for doubly fed EHV transmission line using wavelet MRA. [•] The synchronized fault currents passed through wavelet MRA technique for determining the sixth level detailed coefficients. [•] Sag1, Sbg1, Scg1, Sag2, Sbg2 and Scg2 are used to classify the type of fault occurred in the transmission line. [Copyright &y& Elsevier]

Abstract: In the present investigation a new series of six different Nd3+ doped alkali and mixed alkali (Li, Na, K, Li–Na, Li–K and Na–K) heavy metal (PbO and ZnO) borate glasses were prepared using the melt quenching technique. The amorphous nature of the glass systems has been identified based on the X-ray diffraction analysis. The glass transition studies were carried out using differential scanning calorimetry (DSC). Optical properties were studied by measuring the optical absorption and near infrared luminescence spectra. The Judd–Ofelt (J–O) theory has been applied to calculate J–O intensity parameters, Ω λ (λ=2, 4 and 6) and in turn used to estimate radiative properties of certain transitions. Spectroscopic parameters such as transition probabilities (A T ), branching ratios (β), radiative lifetimes (τ R ) and integrated absorption cross-sections (Σ) were calculated using J–O intensity parameters for all transitions. Using emission spectra, experimental branching ratios and stimulated emission cross-sections (σ P ) are obtained for all the observed emission transitions. [Copyright &y& Elsevier]

Abstract: In the present work, different concentrations of Sm3+doped strontium lithium bismuth borate glasses (SLBiB) have been prepared by melt quench technique and investigated their optical, structural and dielectric properties. The amorphous nature of the prepared glass samples was confirmed by X-ray diffraction and SEM analysis. The spectroscopic properties of these glasses were investigated by recording optical absorption, photoluminescence and decay curve analysis. Judd–Ofelt (J–O) theory has been applied for the f↔f transitions of Sm3+ ions to evaluate J–O intensity parameters, Ωλ (λ =2, 4 and 6). Using the J–O intensity parameters, radiative properties such as transition probabilities (A R), calculated branching ratios (β) and radiative lifetimes (τ) are estimated. From the emission spectra, effective bandwidths (Δλeff ) and stimulated emission cross-sections (σp ) have been obtained for observed emission levels. From the emission spectra, a strong reddish-orange emission corresponding to the transition, 4G5/2 → 6H7/2 was observed. The nature of decay curves of 4G5/2 level for different Sm3+concentrations in SLBiB glass has been analyzed. FTIR spectra were recorded to analyze the functional groups present in the glass matrix. From the dielectric properties, variation of dielectric constant, dielectric loss and ac conductivity of Sm3+ doped different glass samples with the variation of frequency was studied. [Copyright &y& Elsevier]

Abstract: Structural and photoluminescence properties of Dy3+ doped lithium fluoro-borate glasses with the compositions Li2B4O7–BaF2–NaF–MO (where M=Mg, Ca, Cd and Pb), Li2B4O7–BaF2–NaF–MgO–CaO and Li2B4O7–BaF2–NaF–CdO–PbO have been investigated through XRD, FTIR, optical absorption, emission and decay measurements. From the optical absorption spectra, Judd–Ofelt intensity parameters (Ω λ , λ=2, 4 and 6) have been evaluated and are in turn used to predict radiative properties such as radiative transition probabilities (A T), branching ratios (β r) and stimulated emission cross sections (σ p) for all emission levels of Dy3+ ion in different lithium fluoro-borate glass matrices. From the emission spectra, chromaticity color coordinates have been calculated and indicated emission color for all glass matrices. The nature of decay profiles of 4F9/2 state of Dy3+ in all the glass matrices are analyzed. [Copyright &y& Elsevier]

Abstract: Spectroscopic investigations on different concentrations (0.1, 0.5, 1.0, 1.5 and 2.0mol%) of Pr3+ and Nd3+ doped strontium lithium bismuth borate glasses have been done. X-ray diffraction, SEM with EDS, absorption and luminescence spectra were recorded for all the glass matrices and analyzed. X-ray diffraction profiles and SEM images conformed amorphous nature of investigated glass samples. EDS spectra of host glass and Pr3+doped glass matrices gave information about the chemical composition of glass samples. From the absorption spectra of Pr3+ and Nd3+ ions, Judd–Ofelt (J–O) intensity parameters (Ω λ,λ =2, 4 and 6) have been calculated and compared with other glass matrices. The emission characteristics such as radiative lifetimes (τ R), measured and calculated branching ratios (β) and stimulated emission cross-sections (σ P) have been obtained for the observed emission transitions of Pr3+ and Nd3+ ions in the above glass matrix for all the concentrations. From the emission spectra of Pr3+ and Nd3+ doped glass matrices, the effect of concentration on the quenching of intensity of 1D2 → 3H4 transition of Pr3+ ion and 4F3/2 → 4I9/2, 4I11/2 and 4I13/2 transitions of Nd3+ have been studied and discussed. [Copyright &y& Elsevier]

Abstract: Wireless sensor networks are characterized by multi hop wireless lossy links and resource constrained nodes. Energy efficiency is a major concern in such networks. Due to their constraints in computation, memory, and power resources, the performance optimization is a challenging task in these networks. In this paper, fuzzy based secure data aggregation technique is used to select the secure and non-faulty node members for data aggregation. The aggregated data from the cluster heads is transmitted to the sink. This technique efficiently checks for malicious nodes based on the system parameters and maintains a secure aggregation process in the network. By simulation results, we show that our technique has improved throughput and packet delivery ratio with reduced packet drop and less energy consumption based on rate. [Copyright &y& Elsevier]

Abstract: More than 200 insect pests are found growing on pigeonpea. Insects lay eggs, attack and feed on leaves, flowers and developing pods. Plants have developed elaborate defenses against these insect pests. The present work evaluates protease inhibitor (PI) based defense of pigeonpea in leaves and flowers. PIs in the extracts of these tender tissues were detected by using gel X-ray film contact print method. Up to three PIs (PI-3, PI-4 and PI-5) were detected in these tissues as against nine (PI-1–PI-9) in mature seeds. PI-3 is the major component of these tissues. Mechanical wounding, insect chewing, fungal pathogenesis and application of salicylic acid induced PIs in pigeonpea in these tissues. Induction was found to be local as well as systemic but local response was stronger than systemic response. During both local and systemic induction, PI-3 appeared first. In spite of the presence and induction of PIs in these tender tissues and seeds farmers continue to suffer yield loses. This is due to the weak expression of PIs. However the ability of the plant to respond to external stimuli by producing defense proteins does not seem to be compromised. This study therefore indicates that PIs are components of both constitutive and inducible defense and provide a ground for designing stronger inducible defense (PIs or other insect toxin based) in pigeonpea. [Copyright &y& Elsevier]

Abstract: This study has shown that thermally evaporated Ag thin films neither too thin (ultra-thin) nor too thick (foil)—50 and 130nm thick films used here—are ideal for investigating surface modification by a simple iodization procedure for less than ∼15min. XRD, optical, AFM have helped track the interesting changes such as appearance of surface plasmon absorption and initiation of Ag crystalline formation at the nanostructure level. The 50nm, Ag films show gradual development of surface Plasmon resonance and brood visible bands forward by raising absorption in contrast 130nm Ag films show flat absorbance over the wavelength 350–800nm with absorbance systemically reducing upon the increase of iodization time. The systemic trends absorbance spectra should be useful in the design of detector bases in the iodine. Nanostructures supporting localized plasmons are the subject of intense research for their applications in plasmonics including nanophotonic devices, chemical sensors, and optical filters. [Copyright &y& Elsevier]

Abstract: Kinetics of autothermal reforming (ATR) of tetradecane on Pt–Al2O3 catalyst over the temperature range 750–900°C is investigated. Experimental results obtained from NETL (US-DOE) are used for model parameter estimation and validation. Two Langmuir–Hinshelwood–Hougen–Watson (LHHW) type rate models are developed and subjected to parameter estimation and model discrimination. LHHW model in which hydrocarbon is adsorbed on the catalyst surface as alkyl intermediate species by scission of C–H bond gave physically meaningful parameters. Parameters are estimated by using generalized reduced gradient method in spreadsheet and sequential quadratic programming in Matlab. The estimated parameters for the selected model are thermodynamically consistent. The developed kinetic model could capture the experimental behavior of the process and could predict the outlet composition within 25% error. [Copyright &y& Elsevier]

Abstract: This paper presents thermodynamic analysis of commercial diesel with 50ppm sulfur content for the three common modes of reforming operations. Thermodynamic analysis is done to get boundary data for carbon formation and to get the composition of various species for all modes and entire range of operations. For steam reforming operation, steam-to-carbon (S/C) ratio equal to or greater than 2 is required for carbon-free operation in entire temperature range (400–800°C). However, selection of S/C ratio requires the balance between maximizing the hydrogen yield and minimizing the energy input both of which increase with increasing S/C ratio. For partial oxidation operation, O2/C ratio of 0.75 is preferable to maximize hydrogen yield but carbon formation can occur if regions of reactor experience temperatures lower than 700°C. In case of autothermal reforming, for carbon-free operation, temperature of 750°C, O2/C ratio in the range of 0.125–0.25 and S/C ratio greater than 1.25 and ideally 1.75 is recommended. However, enthalpy analysis indicates that it is not possible to reach to thermoneutral point at this condition so it is better to operate O2/C ratio 0.25 or little higher with constant heat supply. A set of three independent reactions is proposed that along with element balance equations can adequately describe the equilibrium composition of six major species—H2, CO2, CO, H2O, CH4, and C for the entire range of reforming operation. [Copyright &y& Elsevier]

Abstract: This paper provides methods for manufacturing alternative fuels from waste cellulosic substrates reinforced by poly furfuryl alcohol (PFA). PFA, as a matrix, is obtained from the condensation polymerization of furfuryl alcohol – a waste of sugarcane bagasse. The processes provided herein can utilize a variety of natural cellulosic substrates derived from, for example, plants such as hemp, ramie, pineapple, abaca but not limited to these. Forest residues and wood chips can also be used as the cellulosic substrates. ISO 5660-1 standards were used to compare the calorific values of the PFA reinforced cellulosic alternative fuels and the existing fossil fuels especially coal as well as cellulosic materials. The calorific value of the cellulosic substrates in any form varies from 5.4MJ/kg to 16.3MJ/kg. Reinforcement of cellulosic substrates with PFA increases the calorific values in the range of 18.9–25.09MJ/kg. We have shown by our novel research that PFA based cellulosic fuels provided herein can be used as effective alternative fuels with heat release/calorific values comparable to any varieties of existing coal. [Copyright &y& Elsevier]

Abstract: Cesium triborate, CsB3O5 (CBO), is an excellent nonlinear optical crystal for ultraviolet light generation. CBO crystals can be grown by top seeded solution growth from self flux solutions. The growth of large-size crystal is difficult because of the multi-nucleation and dissolution of seed during growth. These problems have been avoided and large size crystals (159.2g) of size 50×45×45mm3 (a × b × c) have been grown. The bulk laser-induced damage threshold (LIDT) of CBO was determined using an 1-on-1 technique by the third-harmonic (355nm) light of longitudinal single-mode Q-switch Nd:YAG laser. The bulk LIDT was found to be two times that of fused quartz for a 6ns pulse. The as-grown CBO crystal has been used to generate the highest ever reported third-harmonic power of 103W for the case of a single-pass frequency-conversion system using a high-power Nd:YAG laser. [Copyright &y& Elsevier]