CAMO: A context-aware movie ontology generated from LOD and movie databases

Multimedia Tools and Applications - An ontology is a formal representation of domain knowledge as a set of concepts and their relationships in structured format. Besides various applications,...     

A new controller for boost dc–dc converters based on a novel sliding surface

ABSTRACT

In this paper, two control schemes for boost converters affected by uncertainties in input voltage and load are proposed. The boost converter dynamics is redefined in terms of new state variables to facilitate the use of a disturbance observer that can estimate matched and unmatched disturbances. A sliding surface, which is new in the context of boost converters, is proposed to enable tracking and regulation of output voltage without requiring measurement of input voltage and load current. The stability of the overall system including the disturbance observer, the sliding variable and the output is proved. The performance of the schemes is assessed for regulation of output voltage and tracking of reference voltage by simulation as well as experimentation in which various types of uncertainties and various types of reference voltages are considered.     

High performance multi-layer varistor (MLV) from doped ZnO nanopowders by water based tape casting: Rheology,sintering, microstructure and properties

In this work, we report the fabrication of a high performance multi-layer varistor (MLV) via water based tape casting method using novel compositions of nanomaterials. Bi₂O₃, CaO and Co₃O₄ doped ZnO nanopowders were prepared by solution combustion synthesis (SCS) route, calcined at different temperatures (550, 650, 750 and 850?°C) and characterized by TEM, XRD, SEM and AFM. The nanopowder (crystallite size ~30?nm) calcined at 650?°C for 1?h was used as the starting material for MLV fabrication. Compositions of the slurry containing doped ZnO nanopowders, binder and plasticizer in water solvent were optimized for the fabrication of thick film. The rheological properties of the slurries having different solid loadings were analysed and thick films of various thicknesses (50–500?µm) were prepared by varying the feeding rate of tape casting. The film roughness of 38.3?nm for the thick film made from 40?wt% solid slurry was found to be superior compared to other samples due to the presence of reduced crack and shrinkage. MLV fired at 950?°C for 1.5?h exhibited a coefficient of nonlinearity of 18 and breakdown voltage of 291.5?V that yields superior properties compared to commercial MLVs.     

Investigation of structural,optical, and magnetic properties of Nd-doped Sr2SnO4 Ruddlesden Popper oxide

The samples of Sr_2-xNd_xSnO₄ with x = 0, 0.01, 0.02, 0.04, 0.06, and 0.10 were synthesized by a high-temperature solid-state ceramic route. Rietveld refining of X-ray diffraction results showed that all the synthesized compositions are single phase under tetragonal crystal structure. The presence of functional group and local structure has been studied using FTIR and Raman spectroscopy, respectively. XPS study of samples showed the presence of oxygen vacancy and interstitial oxygen in the sample. Optical band gap of samples analyzed by UV-Vis spectra gradually increases with dopant concentration, and Photoluminescence (PL) spectroscopy study showed most intense emission around 1064 nm. Room-temperature magnetic hysteresis curve in sample SSN2 showed ferromagnetism, slowly decreasing with Nd and becoming antiferromagnetic for higher compositions. Utilizing the absorption state observed in PL as metastable state makes it promising candidate for laser and IR detector application and the ferromagnetic/antiferromagnetic nature of sample makes it suitable candidate for spintronics device applications.     

Comparative study to use nanofluid ZnO and CuO with phase change material in photovoltaic thermal system

In this study, the simultaneous use of nanofluid and phase changing material as a coolant for photovoltaic fluid collector system and its effects are investigated experimentally. Two types of nanofluid are taken for the consideration, that is, ZnO and CuO, which are water‐based fluid. The experiments are performed in five different types of photovoltaic thermal system conventional: PT, PVT (ZnO), PVT (CuO), PCM medium (PVT/PCM/ZnO), and PCM medium (PVT/PCM/CuO). The results are obtained for surface temperature, energy, and thermal efficiency, and it is compared with each other. Further, the effect of the nanofluid as the effective alternative for pure deionized water is measured. From the results, it is evident that the PVT/PCM/CuO system minted 15% high electric output compared with convention module. Furthermore, the addition of the CuO nanofluid increases the thermal output significantly up to 8% for PVT and 12% for PCM without energy consumption. It also found that the nanofluid increases the overall energy efficiency of the system compared with convention PV.     

Green hydroelectrical energy source based on water dissociation by nanoporous ferrite

Dissociation of water molecule occurs on octahedrally coordinated unsaturated suface cations and oxygen vacancies created by lithium substitution in magnesium ferrite. Lower synthesis temperature of ferrite has generated nanopores in microstructure. Dissociated hydronium and hydroxyl ions are transported through surface and capillary diffusion in porous ferrite network towards attached Zn and Ag electrodes. Water molecule dissociation ability of nanoporous ferrite has been exploited to develop a green electrical energy cell, which is a combination of material science and electrode chemistry. The innovated cell has been nomenclatured as hydroelectric cell (HEC). When HEC is partially dipped in deionized water, spontaneously hydroxide and hydronium ions are produced by water molecule dissociation. Hydronium ions trapped in nanopores develop enough electric field that further dissociates physisorbed water molecules. Thereby, the process of water molecule dissociation is accelerated in a bigger way to increase ionic current in the cell. Oxidation of Zn electrode by hydroxide ion and reduction of H₃O⁺ at Ag electrode develop voltage and electric current in the cell. The HEC cell of a 17 cm² area is able to generate a short circuit current of 82 mA and 920 mV emf with a maximum output power of 74 mW, which is three order higher than reported output power 1.4 μW/cm² produced by water in cement matrix. Hydroelectric cell performance is repetitive, stable and possesses potential to replace traditional ways of generating renewable energy in terms of cost and safety. Copyright © 2016 John Wiley & Sons, Ltd.     

Effect of heating and acidic pH on characteristics of wheat gluten suspension

The effects of different pH treatments with and without heating on the characteristics of wheat gluten suspension was investigated. At pH 1, maximum changes in colour were observed with a concurrent 65% decrease in protein free-thiol content compared to the control gluten. The SDS-Extractability of protein (SDS-EP) chromatogram eluted at lower retention time and the presence of bands at the top lane even during reducing conditions in SDS-PAGE gel suggested complex formation involving bonds other than disulphides. An increase in the free-amino group content and the presence of an additional peak at a higher retention time in the SDS-EP chromatogram was suggestive of hydrolysis. At pH 2 and 3, similar decreases in SDS-EPs and free-thiol content indicated formation of complexes. When heated, the free-thiol content of the dispersions increased compared to the non-heated dispersions indicating disruption of disulphide bonds with changes in gluten structure and size distribution.     

Effect of iron alloying in evolution of nanostructure and microstructural stability in nickel

Nanocrystalline materials show many interesting properties such as high strength and hardness due to nanosized grains and high density of interfaces. In this context, the present work reports the effect of Fe (iron) addition in Ni (nickel) on nanostructure retention during the annealing of Ni-Fe alloy (with 0, 18.5, 28.5 and 43 wt% Fe) at 450 °C for 16 h. Furthermore, effect of annealing on the deformation mechanism was investigated. The integral breadth method revealed the decrease in grain size with increase in wt% Fe in Ni. The strain rate sensitivity exponent which is a signature of operating deformation mechanism showed a higher value (0.10803) in case of Ni-18.5 wt% Fe during nanoindentation. However, Ni-0 wt% Fe, Ni-28.5 wt% Fe and Ni-43 wt% Fe were characterized by a relatively low strain rate sensitivity exponent (between 0.02069 and 0.10803). Results indicated the presence of Hall-Petch relationship up to 18.5 wt% Fe and inverse Hall-Petch relationship above 18.5 wt% Fe.