Redox supercapacitor performance of nanocrystalline molybdenum nitrides obtained by ammonolysis of chloride- and amide-derived precursors

Reactions of MoCl5 or Mo(NMe2)4 with ammonia result in cubic ?-Mo2N or hexagonal ?1-MoN depending on reaction time and temperature. At moderate temperatures the cubic product from Mo(NMe2)4 exhibits lattice distortions. Fairly high surface areas are observed in the porous particles of the chloride-derived materials and high capacitances of up to 275 F g?1 are observed when electrodes made from them are cycled in aqueous H2SO4 or K2SO4 electrolytes. The cyclic voltammograms suggest charge is largely stored in the electrochemical double layer at the surface of these materials. Amide-derived molybdenum nitrides have relatively low surface areas and smaller capacitances, but do exhibit strong redox features in their cyclic voltammograms, suggesting that redox capacitance is responsible for a significant proportion of the charge stored

An efficient adaptive fusion scheme for multifocus images in wavelet domain using statistical properties of neighborhood

In this paper we present a novel fusion rule which can efficiently fuse multifocus images in wavelet domain by taking weighted average of pixels. The weights are adaptively decided using the statistical properties of the neighborhood. The main idea is that the eigen value of unbiased estimate of the covariance matrix of an image block depends on the strength of edges in the block and thus makes a good choice for weight to be given to the pixel, giving more weightage to pixel with sharper neighborhood. The performance of the proposed method have been extensively tested on several pairs of multifocus images and also compared quantitatively with various existing methods with the help of well known parameters including Petrovic and Xydeas image fusion metric. Experimental results show that performance evaluation based on entropy, gradient, contrast or deviation, the criteria widely used for fusion analysis, may not be enough. This work demonstrates that in some cases, these evaluation criteria are not consistent with the ground truth. It also demonstrates that Petrovic and Xydeas image fusion metric is a more appropriate criterion, as it is in correlation with ground truth as well as visual quality in all the tested fused images. The proposed novel fusion rule significantly improves contrast information while preserving edge information. The major achievement of the work is that it significantly increases the quality of the fused image, both visually and in terms of quantitative parameters, especially sharpness with minimum fusion artifacts

Efficient photocatalysis through conductive polymer coated FTO counter electrode in platinum free dye sensitized solar cells

This is the final version. Available on open access from Elsevier via the DOI in this recordPlatinum-free counter electrodes are crucial for developing cost effective solar energy harvesting technology. We describe here the fabrication of efficient platinum free FTO counter electrodes for dye sensitized solar cells based on pristine polyaniline, polyaniline doped with sulfuric acid, ammonuim lauryl sulfate, as well as binary doped with sulfuric acid and ammonium lauryl sulphate. The characteristics of these counter electrodes were analyzed using cyclic voltammetry, photocurrent density–voltage and electrochemical impedance spectroscopy measurements. At optimized fabrication conditions, the counter electrode shows significantly high photoelectric conversion efficiency of 4.54% compared to 4.03% for reference platinum counter electrode. Charge transfer resistance at the interface between electrolyte and counter-electrode is also decreased for the optimized polyaniline based counter electrode. Furthermore, the device presented characteristics of multiple start/stop ability and fast activity. The simple preparation procedure, low cost and improved photoelectric properties permit fabricated counter electrode to be a reliable alternative for dye sensitized solar cells.Engineering and Physical Sciences Research Council (EPSRC)Alexander von Humboldt Foundation, GermanyHigher Education Commission Pakista

Human-mobility-based sensor context-aware routing protocol for delay-tolerant data gathering in multi-sink cell-phone-based sensor networks

Ubiquitous use of cell phones encourages development of novel applications with sensors embedded in cell phones. The collection of information generated by these devices is a challenging task considering volatile topologies and energy-based scarce resources. Further, the data delivery to the sink is delay tolerant. Mobility of cell phones is opportunistically exploited for forwarding sensor generated data towards the sink. Human mobility model shows truncated power law distribution of flight length, pause time, and intercontact time. The power law behavior of inter-contact time often discourages routing of data using naive forwarding schemes. This work exploits the flight length and the pause time distributions of human mobility to design a better and efficient routing strategy. We propose a Human-Mobility-based Sensor Context-Aware Routing protocol (HMSCAR), which exploits human mobility patterns to smartly forward data towards the sink basically comprised of wi-fi hot spots or cellular base stations. The simulation results show that HMSCAR significantly outperforms the SCAR, SFR, and GRAD-MOB on the aspects of delivery ratio and time delay. A multi-sink scenario and single-copy replication scheme is assumed

Adiposity is associated with early reduction in bone mass in pediatric inflammatory bowel disease

Background: The effect of adiposity on bone mass in the early phases of inflammatory bowel disease (IBD) in children and adolescents is unclear. Aims: To determine the role of adiposity on bone mass in the first 3 years of diagnosis of IBD. Hypothesis: Increased adiposity will be associated with increased bone mass in both the controls and IBD subjects. Setting: University tertiary institution. Methods: Height-adjusted bone mineral density (BMD) z-scores of 25 subjects, age 13.97 ± 2.70y, diagnosed with IBD for \u3c 4 years were compared to 24 controls, age 13.65 ± 2.60y. Overweight was defined as BMI of ≥85th but \u3c95th percentile, and obesity as BMI ≥95thpercentile. Severity of IBD was determined by the Pediatric Crohn’s Disease Activity Index and Lichtiger Colitis Activity Index. Results: Prior to stratification by BMI criterion, height-adjusted BMD z-scores were non-significantly lower in IBD subjects vs. controls for both the femoral neck (-0.8 ± 1.1 vs. -0.06 ± 1.1, p=0.070) and lumbar vertebrae (-0.4 ± 1.2 vs. 0.2 ± 1.2, p=0.086). Following stratification, height-adjusted BMD z-scores were significantly lower in the overweight/obese IBD subjects vs. overweight/obese controls for femoral neck (-0.9 ± 0.9 vs. 0.3 ± 1.3, p=0.032); and non-significantly lower for the lumbar spine z-score (-0.4 ± 1.6 vs. 0.5 ± 1.3, p=0.197). BMD z-score had no relationship with the duration of disease, steroid therapy, and the severity of disease. Conclusion: Adiposity was associated with reduced bone mass in the early phases of IBD, but with increased bone mass in the controls

Hierarchical fusion using vector quantization for visualization of hyperspectral images

Visualization of hyperspectral images that combines the data from multiple sensors is a major challenge due to huge data set. An efficient image fusion could be a primary key step for this task. To make the approach computationally efficient and to accommodate a large number of image bands, we propose a hierarchical fusion based on vector quantization and bilateral filtering. The consecutive image bands in the hyperspectral data cube exhibit a high degree of feature similarity among them due to the contiguous and narrow nature of the hyperspectral sensors. Exploiting this redundancy in the data, we fuse neighboring images at every level of hierarchy. As at the first level, the redundancy between the images is very high we use a powerful compression tool, vector quantization, to fuse each group. From second level onwards, each group is fused using bilateral filtering. While vector quantization removes redundancy, bilateral filter retains even the minor details that exist in individual image. The hierarchical fusion scheme helps in accommodating a large number of hyperspectral image bands. It also facilitates the midband visualization of a subset of the hyperspectral image cube. Quantitative performance analysis shows the effectiveness of the proposed method

A MATHEMATICAL MODEL TO STUDY THE SIMILARITIES OF BLOOD FLUID MODELS THROUGH INCLINED MULTI-STENOSED ARTERY

A mathematical model is presented to comparative steady of the flow behavior of Casson’s and Bingham Plastic fluid model through an inclined tube of non-uniform cross-section with multiple stenoses. The equation describing the flow has been solved and the expressions parameters on flow variables have been studied. The present study may be helpful for better understanding the flow characteristics of blood having multiple stenoses. The graphical representations have been made to validate the analytical findings with a view of its applicability to stenotic diseases. It is found that the flow of resistance increases with the height of the stenosis but decreases with the angle of inclination. The flow characteristics namely, velocity, pressure gradient, flow rate, resistance to flow have been derived. It is shown that the resistance to flow increases with the height of the secondary stenosis as well as with the yield stress. The results are compared with the available data presented by previous researchers

Multifocus image fusion algorithm using iterative segmentation based on edge information and adaptive threshold

This paper presents algorithm for multifocus image fusion in spatial domain based on iterative segmentation and edge information of the source images. The basic idea is to divide the images into smaller blocks, gather edge information for each block and then select the region with greater edge information to construct the resultant 'all-in-focus' fused image. To improve the fusion quality further, an iterative approach is proposed. Each iteration selects the regions in focus with the help of an adaptive threshold while leaving the remaining regions for analysis in the next iteration. A further enhancement in the technique is achieved by making the number of blocks and size of blocks adaptive in each iteration. The pixels which remain unselected till the last iteration are then selected from the source images by comparison of the edge activities in the corresponding segments of the source images. The performance of the method have been extensively tested on several pairs of multifocus images and compared quantitatively with existing methods. Experimental results show that the proposed method improves fusion quality by reducing loss of information by almost 50% and noise by more than 99%