Extended Use of Linear Graph Theory for Analysis of Pipe Networks

Linear graph theory used for pipe network analysis is to make the method systematic. A numerical method that uses linear graph theory is presented for the steady-state analysis of flow and pressure in a pipe network including its hydraulic components (pumps, valves, junctions, etc.). The proposed method differs from other linear graph methods in terms of the linear graph and the selection of its tree. The solution algorithm uses a function that depends on a power law to update the pipe flows in successive iterations. The exponents of this function are chosen to obtain a fast convergence rate even for large errors in the assumption of initial pipe flows. The convergence rate of the proposed method is validated using an error function and is compared to those of other methods. Some typical networks are analyzed to check the reliability of the proposed method. The results demonstrate the superior conditioning of the proposed method.     

Impact of open dumping of municipal solid waste on soil properties in mountainous region

This paper presents the effect of open dumping of municipal solid waste (MSW) on soil characteristics in the mountainous region of Himachal Pradesh, India. The solid waste of dumpsite contains various complex characteristics with organic fractions of the highest proportions. As leachate percolates into the soil, it migrates contaminants into the soil and affects soil stability and strength. The study includes the geotechnical investigation of dump soil characteristics and its comparison with the natural soil samples taken from outside the proximity of dumpsites. The geochemical analysis of dumpsite soil samples was also carried out by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). Visual inspection revealed that the MSW consists of high fraction of organics, followed by paper. The soil samples were collected from five trial pits in the dumpsites at depths of 0.5 m, 1 m and 1.5 m. Then the collected soil samples were subjected to specific gravity test, grain size analysis, Atterberg's limit test, compaction test, direct shear test, California bearing ratio (CBR) test and permeability analysis. The study indicated that the dumpsite soils from four study regions show decreasing trends in the values of maximum dry density (MDD), specific gravity, cohesion and CBR, and increasing permeability as compared to the natural soil. The results show that the geotechnical properties of the soils at all four study locations have been severely hampered due to contamination induced by open dumping of waste.     

Studies on EVA‐Based Wax Fuel for Launch Vehicle Applications

A fuel for the hybrid rocket system was developed. The attempts made to improve the mechanical properties of wax by adding EVA (ethylene vinyl acetate) are illustrated. It was observed that the mechanical properties obtained by adding EVA to wax were dependent on the process of curing the fuel specimen. A proprietary method of curing the fuel specimen was established. The percentage elongation obtained with 20 % EVA and 80 % of wax was around 17 %, which was much higher than the values obtained with pure wax (4 %). It was observed from the study that the higher the percentage of EVA content in wax was, the better the mechanical properties were. Regression rate studies with EVA and wax combination were carried out. It was observed that the regression rate decreased upon addition of EVA in wax. This reduction was compensated by using a bluff body at the head end. The regression rate obtained with 20 % EVA and 80 % wax even with the use of bluff body is lower than that obtained with pure wax, but is around 3.5 times the regression rate obtained with polymeric fuels.     

Utilizing Semantic Knowledge for Access Control in Pervasive and Ubiquitous Systems

Controlling access in pervasive environments is crucial and a significant challenge because users and devices can connect from anywhere which results in users and resources becoming available at any point of time and location depending on the situation. Access control policies for this type of environment are required to conform to high-level business notions. In pervasive environments, these high-level notions refer to contexts of the situation which can change unpredictably and must be interpreted semantically to maintain proper access control. Therefore, it is necessary to have a formal representation that represents semantics of the contexts, reflects the change of the situation, and can be shared and understood by a policy system. This paper addresses these issues by introducing a context management system that uses a semantic web approach as an underlying mechanism to model and represent semantics of the contexts. The system stores current contexts in a semantic knowledge base which is used by a semantic access control system in order to form access control policies and evaluate policies at run time. The approach is validated through a proof of concept implementation that includes performance results of the context management system as it responds to a change of the situation.     

A Novel FRFT Beamformer for Rayleigh Faded Channels

A method of optimal beamforming for flat Rayleigh faded channels using the Fractional Fourier Transform (FRFT) is considered in this paper. It has been demonstrated through simulations that optimal beamforming with FRFT allows smaller mean-square errors in restoring signals degraded with linear time-or frequency variant distortions and Additive White Gaussian Noise. This is made possible by the additional flexibility that comes with free parameter ‘a’ of the fractional Fourier transform as oppose to the classical Fourier transform (FT). The method is especially useful in moving source problems, where Doppler Effect produces frequency shift when the source is moving, as in mobile and wireless communication where user produces the frequency shift while moving. In this paper it is shown through simulations that beamforming in fractional domain reduces BER as compared to time or frequency domain.     

Functionalization of conducting polymer with novel Co(II) complex: Electroanalysis of ascorbic acid

We report for the first time the functionalization of a conducting polymer with a metal complex in order to develop a new type of catalytic material exhibiting better electronic communication through their delocalized π electrons. The Co(II) complex having hydroxyl group as functional moiety is chemically coupled with carboxyl group of polyanthranilic acid which itself is a self doped conducting polymer. The covalent linkage between Co(II) and –OH group is confirmed using UV–vis, FT-IR and NMR spectroscopic techniques. The Co(II) complex functionalized polymer does exhibit excellent redox behavior and stability with mixed properties of Co(II) complex and π-conjugated polymer. The material possesses potential benefits in sensors/biosensor applications and it is demonstrated for the electroanalysis of ascorbic acid at a level of nano molar concentration.     

Electrospray mass spectrometric characterization of bimetallic group 8 — Gold clusters

Bimetallic clusters containing gold in conjunction with Group 8 metals have been intensively studied as it is proposed that these compounds may find uses as catalysts or materials (or as precursors to catalysts/materials). These types of compounds are very difficult to characterize by the mass spectrometric techniques traditionally used to analyse transition metal clusters. In this paper we report a derivatization method employing electrospray ionization mass spectrometry that is reliable and informative for these types of compounds.