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Si–O–N–F has been studied as a new candidate material for a high transmittance attenuated phase shift mask (HT-Att-PSM). The requirements of HT-Att-PSM are 20 ± 5% transmittance and 180° phase shift at the exposure wavelength (157 nm) and less than 40% transmittance at the inspection wavelength (193 nm). Si–O–N–F films were deposited with varying process parameters, such as gas flow rate and deposition time, to find optimum conditions to meet the above requirements. In this study, the effects of process parameters on the optical properties and the degradation of Si–O–N–F films were examined. To satisfy the requirements of HT-Att-PSM, a new mask structure was suggested and analyzed. [Copyright &y& Elsevier]

In this paper, the dynamic implosion responses of ring-stiffened cylindrical tubes under external hydrostatic pressure are reported. The ring-stiffened cylinder models were fabricated from commercial seamless aluminium-alloy 6061-T6 tubes. Six external stiffened models were constructed: three models with three stiffeners, and the other three with five stiffeners. To quantify the effects of stiffening on the structural behaviour, implosion tests were also performed on another three unstiffened tube models. In this study, a total of nine tube models were tested until their failure. Implosion was initiated by increasing the hydrostatic pressure in the chamber until the tubes collapsed, and the effects of different types of pressurising media were investigated: (i) water only and (ii) water and nitrogen gas combined. The implosion pressure pulse near the collapsing tube was recorded during the event. The models with five stiffeners increased the implosion pressure pulse by approximately 3.5 times compared with the unstiffened model. • Experimental investigation of implosion response of ring-stiffened aluminium-alloy tube. • The effects of stiffening on the implosion response was studied. • The dynamic pressure generated during the implosion was measured and compared. • The effects of different pressurising media were investigated: (i) water only; (ii) combined water and nitrogen. [ABSTRACT FROM AUTHOR]

Purpose: In Southeast Asia, the renewable energy produced from hydropower systems has significant potential. Therefore, adequate development is needed to prevent future energy-related crises. This study, therefore, aims to determine the variations effects in geometry and the geometrical factors on turbine performance. Design/methodology/approach: The developed aspects are selected to determine the blade shape, its number and multistage requirements. The study was conducted in 3D simulation, with Ansys software used to calculate a series of computational fluid dynamic problems. The aspect ratio applied in this study utilized the ratio of the overall diameter of the rotor height (D / H), which is 1. Findings: The results showed that the highest Cp-max value, number of blades and stages were 0.2, two and three, respectively. Furthermore, these attributes combined to improve the performance of hydroturbines. Research limitations/implications: The research was fully conducted using numerical simulation, which requires sustainable research in the form of laboratory experiments. Also, pioneer experiments were conducted using benchmarking to ensure the results obtained are reliable. Practical implications: Hydropower is one of the best renewable energy sources in Indonesia with a large potential in the archipelago and tropical countries due to rivers and various water sources. The current generated is a useful reference for Savonius design. Originality/value: The originality of this study is to examine the three aspects of the geometry of the rotor, such as the number and shape of blades, as well as the stages in the same boundary conditions. Therefore, the comparison of the effects of changes in geometry on turbine performance is more acceptable and complete compared to the pioneer works, which focused on a parameter. This research combines several aspects to determine the effect of rivers and various water sources on the hydroturbine. [ABSTRACT FROM AUTHOR]

Chemical looping combustion (CLC) is attracting attention as a promising technology for carbon dioxide separation. Oxygen carrier materials are the most important factor in determining the efficiency of CLC. In this paper, we present MgMnO 3-δ with a defect cubic spinel structure as an oxygen carrier material with high efficiency, low cost, and stable properties. MgMnO 3-δ has a non-stoichiometric oxygen content of MgMnO 2.68 . The reduced composition of MgMnO 3-δ in H 2 , CO, or CH 4 is a complete solid solution of (Mg,Mn)O. The redox reaction from MgMnO 3-δ to (Mg,Mn)O is reversible and stable. Interestingly, MgMnO 3-δ also shows a chemical looping oxygen uncoupling (CLOU) phenomenon and is reduced to MgMn 2 O 4 and MgO in N 2 at 900 °C. The oxygen transfer capacities of MgMnO 3-δ under 15% H 2 /N 2 , 15% CO/CO 2 , 15% CH 4 /N 2 , and 15% CH 4 /CO 2 are 8.34, 8.56, 8.42, and 8.74 wt%, respectively, at 900 °C. The oxygen transfer capacity was well maintained during the 5th redox cycle. No phase or structure changes or agglomeration occurred as the redox cycle number increased. Moreover, MgMnO 3-δ has a high tolerance to carbon deposition when used in CO or CH 4 fuels. [ABSTRACT FROM AUTHOR]

This paper outlines empirical formulas to provide adequate predictions of the ultimate strength of ring-stiffened cylinders under hydrostatic pressure. The ultimate strength formulation was derived from published test data found in the open literature. The formulas consider the failure mode interactions, which include the parameter of shell yielding, inter-frame buckling, overall buckling, and stiffener tripping. The failure modes were inserted in the quadratic Merchant-Rankine formula. Afterward, the knockdown factors were empirically derived to best fit the actual collapse pressure. It is found that the proposed formulation can predict the ultimate strengths of ring-stiffened cylinders more accurately and consistently than other codified rules (PD5500, GL, ABS, API). The simple criterion for the assessment of failure modes was also provided. Furthermore, parametric studies were conducted to observe the effect of the design parameter on sizing the ring-stiffened cylinder when the failure modes can be predicted. [ABSTRACT FROM AUTHOR]

CoTiO3 perovskite was investigated as an alternative oxygen carrier for chemical looping combustion. The cyclical reduction and oxidation reaction were performed in TGA equipment. When the CoTiO3 particles were reduced, oxygen transfer capacity was maintained at 10.2 wt% during 10th cycles with 15% H2/N2 and 10.5 wt% with 15% CH4/N2. It was similar to the theoretical oxygen transfer capacity, 10.3 wt%. The maximum oxygen transfer rate was 0.015 mmol O2/g/sec during the reduction process. For 15% CH4/N2, the transfer rate was 0.03 mmol O2/g/sec which was twice that resulting from using hydrogen. From XRD and TPR results, CoTiO 3 was transformed to Co/TiO 2 and CoC x during reduction with hydrogen and methane, respectively. After all cycles, the particles were not agglomerated and appeared to be similar to its initial state. Conclusively, CoTiO3 could be a potential candidate as an oxygen carrier because CoTiO 3 shows an improved oxygen transfer capacity and rate. [ABSTRACT FROM AUTHOR]

For safety design of structures against fire loads, time-variant geometry and material properties depending on the temperature should be considered with fluid-structure interaction (FSI) analysis. One-way FSI analysis is generally applied due to a time consuming task. But, it has big difference of structural response between conducting one-way and two-way FSI analysis. And two-way analysis is also affected by time increment of analysis for updating the geometry, and fire loads. The aim of this study is to investigate the effect of time increments on two-way FSI analysis of structures subjected to jet fire, and to suggest a proper time increment for two-way FSI analysis. In the present study, geometries and material properties are updated at every time increments, and kinds of two-way FSI analysis are performed with different time increments by using computational fluid dynamics (CFD) and nonlinear finite element analysis (NLFEA) and an interface program between CFD and NLFEA. [ABSTRACT FROM AUTHOR]

The catalytic activity and carbon deposition for toluene steam reforming were investigated by adding promoters such as K, Ca and Mn on 10 wt% Ni-based catalysts. The toluene steam reforming experiments were carried out at temperature of 800 °C under S/C ratio = 3. Catalyst characteristics were evaluated using XRD, BET, TPR and TGA. Ni/dolomite showed the highest hydrogen production and the toluene conversion efficiency to CO and CO 2 among the catalysts. A slight enhancement effect was observed by adding K or Ca. By adding Mn on Ni/dolomite, the better toluene conversion efficiency to CO and CO 2 was obtained than K and Ca and maintained constantly because of the resistance of carbon deposition. Conclusively, the addition of Mn on Ni/dolomite could give the stable catalytic activity for toluene steam reforming by suppressing the carbon deposition. [ABSTRACT FROM AUTHOR]

Highlights: [•] La0.9Sr0.1Cr1−2x Mn x Co x O3±δ (x =0.1–0.3) catalysts showed high CO conversion of 90%. [•] La0.9Sr0.1Cr1−2x Mn x Co x O3±δ (x =0.1–0.3) catalysts reached the equilibrium CO conversion over 450°C. [•] More active compared to the commercial high-temperature shift catalyst. [ABSTRACT FROM AUTHOR]

Abstract: The steam reforming of benzene as a model compound of biomass gasification tar was carried out over various Ni/metal oxide catalysts. The effects of the support, temperature, Ni-precursor, Ni loading and reaction time were examined, and their catalytic performance was compared with that of a commercial Ni catalyst. Among the Ni/metal oxide catalysts used, 15wt% Ni/CeO2(75%)–ZrO2(25%) showed the highest catalytic performance owing to its greater redox characteristics and increased surface area, irrespective of the reaction temperature. The catalytic activity of 15wt% Ni/CeO2(75%)–ZrO2(25%) was higher than that of the commercial Ni catalyst. Moreover, the catalyst activity was retained due to its excellent resistance to coke deposition even after 5h. The Ni-precursor played a critical role in the catalytic activity. With the exception of nickel nitrate, all the Ni-precursors (chloride and sulfate) caused deactivation of the catalyst. [Copyright &y& Elsevier]

Abstract: Fast pyrolysis of Miscanthus was investigated in a bench-scale fluidized bed reactor for production of bio-oil. Process conditions were varied for temperature (350–550°C), particle size (0.3–1.3mm), feed rate and gas flow rate. Pyrolysis temperature was the most influential parameter upon the yield and properties of bio-oil. The highest bio-oil yield of 69.2wt.% was observed at a temperature of 450°C which corresponded to the end of the thermal composition of hemicellulose and cellulose. In the bio-oil, the water content was 34.5wt.%, and the main compounds in the organic fraction were phenolics and oxygenates. With increasing temperature, the amount of oxygenates in the bio-oil decreased gradually while that of water and aromatics increased rapidly. The bio-oil yield was not significantly affected by particle sizes or feed rates. The use of product gases as a fluidizing medium aided in increasing bio-oil yield. [Copyright &y& Elsevier]

[Display omitted] • Woody sawdust pyrolysis was performed to produce phenolic-rich bio-oil. • Raising temperature increased phenolics, while decreased acids. • Torrefaction increased the production of phenolics at the expense of oxygenates. • Fractional condensation effectively separated phenolics from harmful content. • Synergetic effects of torrefaction and fractional condensation were demonstrated. This study evaluated the effects of the pyrolytic temperature, torrefaction, and fractional condensation alongside the combined efficiency of torrefaction and fractional condensation on the production of high-quality bio-oil from woody sawdust (WS) pyrolysis for the first time. The proportion of acids decreased gradually with increasing temperature from 300 to 600 °C, while the selectivity of phenolic compounds was enhanced. An increase in the torrefaction severity caused a significant decrease in the bio-oil yield at the pyrolysis stage but favorably increased the selectivity of phenolics and mitigated the fraction of oxygenated compounds. In fractional condensation, the proportion of total oxygenates was increased with decreasing condensing temperature from the first condenser (Con 1) (250 °C) to the fourth condenser (Con 4) (-20 °C). On the other hand, most phenolics were condensed in Con 1 and then showed a decreasing trend with a decrease in temperature. Integrating torrefaction and fractional condensation decreased the oxygenated content dramatically while increasing the selectivity of phenolic content significantly (up to 89.48%) under high- and mild- temperatures condensation, suggesting a functional improvement. Overall, the torrefaction of biomass combined with fractional condensation in biomass pyrolysis is a promising approach to produce biofuels. [ABSTRACT FROM AUTHOR]

• CaCo based oxygen carrier showed the superior oxygen transfer capacity and rate. • Most oxygen evolution came from the transformation of crystal structure during reduction. • Enhanced oxygen transfer capacity, 16.5 wt% was obtained and maintained under repeated redox cycles. We investigated whether a CaCo-based oxygen carrier could be an oxygen-transfer particle for Chemical Looping Combustion (CLC). The analysis was carried out using TGA to see the redox characteristics of the cycle. 15% H 2 /N 2 was used as the reducing gas, and air was used as the oxidizing gas. The CaCo-based oxygen carrier maintained a high oxygen-transfer capacity of about 16 wt% for 10 cycles. Also, the oxygen-transfer rate was relatively stable over 10 cycles. The maximum oxygen-transfer rate was about 0.022 mmol O 2 /g/s in the reduction section. The maximum oxygen-transfer rate in the oxidation section was about 0.022 mmol O 2 /g/s. From the XRD results, the CaCo-based oxygen carrier exhibited a similar XRD pattern after the 10th-cycle oxidation, which confirmed that the phase was stably recovered even though the CaCo-based oxygen carrier was completely reduced to CaO and Co metal during reduction. Although some agglomeration was observed, it did not affect overall oxygen transfer capacity and rates. Conclusively, CaCo-based oxygen carriers show high performance and phase stability, and thus can be potential candidates for oxygen carriers in CLC process. [ABSTRACT FROM AUTHOR]

This paper reports experimental and numerical investigations on the ultimate strength responses of steel-welded, ring-stiffened conical shells when subjected to external hydrostatic pressure. Four small-scale shell models were fabricated from general structural steel by cold bending and arc welding. First, hydrostatic pressure tests were performed to investigate the collapse behaviour of the models. The influences of different parameters were also studied experimentally. Before the experiments, quasi-static tensile tests were performed to obtain detailed characterisation of the test model material. In addition, the initial imperfection of the shell and other as-built geometry parameters were carefully measured. The test was conducted using compressed water in a small-sized chamber and loaded to collapse. Three models with heavy stiffeners were failed by local buckling at the shell between the ring frames. Another model failed by the overall buckling of the adjacent frames together with the shell. The numerical computations were performed on the finite element code of ABAQUS FEA. The imperfection due to fabrication, such as initial out-of-circularity, and residual stresses due to welding are simulated. The quasi-static response was compared with the experimental load and plastic deformation curves. The numerical results revealed a close agreement between the collapse pressure prediction and failure modes of the simulation and the experiment. • Experimental works on welded steel ring-stiffened conical shell subjected to external hydrostatic pressure are reported. • Investigation on local and overall failures were conducted. • Non-linear FE analyses on buckling behaviour were performed. • Accuracy of proposed formulation in good agreement with test results. [ABSTRACT FROM AUTHOR]

The safety of ships in regards to collisions and groundings, as well as the navigational and structural aspects of ships, has been improved and developed up to this day by technical, administrative and nautical parties. The damage resulting from collisions could be reduced through several techniques such as designing appropriate hull structures, ensuring tightness of cargo tanks as well as observation and review on structural behaviors, whilst accounting for all involved parameters. The position during a collision can be influenced by the collisions' location and angle as these parts are included in the external dynamics of ship collisions. In this paper, the results of several collision analyses using the finite element method were used and reviewed regarding the effect of location and angle on energy characteristic. Firstly, the capabilities of the structure and its ability to resist destruction in a collision process were presented and comparisons were made to other collision cases. Three types of collisions were identified based on the relative location of contact points to each other. From the results, it was found that the estimation of internal energy by the damaged ships differed in range from 12%-24%. In the second stage, the results showed that a collision between 30 to 60 degrees produced higher level energy than a collision in the perpendicular position. Furthermore, it was concluded that striking and struck objects in collision contributed to energy and damage shape.

Catalytic fast pyrolysis of waste rice husk was carried out using pyrolysis-gas chromatography/mass spectrometry [Py-GC/MS]. Meso-MFI zeolite [Meso-MFI] was used as the catalyst. In addition, a 0.5-wt.% platinum [Pt] was ion-exchanged into Meso-MFI to examine the effect of Pt addition. Using a catalytic upgrading method, the activities of the catalysts were evaluated in terms of product composition and deoxygenation. The structure and acid site characteristics of the catalysts were analyzed by Brunauer-Emmett-Teller surface area measurement and NH3 temperature-programmed desorption analysis. Catalytic upgrading reduced the amount of oxygenates in the product vapor due to the cracking reaction of the catalysts. Levoglucosan, a polymeric oxygenate species, was completely decomposed without being detected. While the amount of heavy phenols was reduced by catalytic upgrading, the amount of light phenols was increased because of the catalytic cracking of heavy phenols into light phenols and aromatics. The amount of aromatics increased remarkably as a result of catalytic upgrading, which is attributed to the strong Brönsted acid sites and the shape selectivity of the Meso-MFI catalyst. The addition of Pt made the Meso-MFI catalyst even more active in deoxygenation and in the production of aromatics.