Conducting ferromagnetic copolymer of aniline and 3,4‐ethylenedioxythiophene containing nanocrystalline barium ferrite particles

This article reports the synthesis of conducting ferromagnetic complex of 3,4‐ethylenedioxythiophene (EDOT) and aniline (An) containing M‐type hexagonal barium ferrite (BaFe₁₂O₁₉) particles using in situ emulsion polymerization and electrochemical oxidative polymerization. Magnetic and conductivity studies reveal that the conducting ferromagnetic complex possesses high‐saturation magnetization (M_s) value of 29.2 emu/g and conductivity of the order of 0.256 S/cm determined through vibrating sample magnetometer and four‐probe method. Microwave measurement has shown the reflection loss (R_L) of ?12.1 dB in Ku‐band that can be used as a microwave absorbing material. The polymer complex was further characterized by techniques like X‐ray diffraction, Fourier transform infrared, UV–visible, cyclic voltammetry, and thermal analysis with thermogravimetric analysis. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci 2008     

Effects of hypochlorite exposure on flux through polyethersulphone ultrafiltration membranes

Polyethersulphone ultrafiltration membranes with a nominal molecular weight cut off of 10 kDa were degraded in solutions of sodium hypochlorite over a range of pH values at 55 °C to achieve exposure measured in ppm-days of chlorine exposure. The degraded membranes were tested, using an ÄKTAcrossflow? system, for clean water flux, demineralised whey flux and protein rejection. The water fluxes for three membranes (new, 10,000 ppm-day pH 12, and 10,000 ppm-day pH 9) were found to be about 100, 200 and 400 L m^?2 h^?1, respectively with cross flow at 1 bar transmembrane pressure. However whey fluxes were about 23, 5, and 6 L m^?2 h^?1 for the same three membranes. Size exclusion chromatography of the permeates showed significant permeation of α-lactalbumin and β-lactoglobulin through membranes degraded at pH 9 for 20,000 ppm-days, while almost no permeation was found for degradation at pH 12.These results show that hypochlorite degradation affected fluxes by at least two mechanisms. It was likely that membrane pitting increased the pore size causing increased water flux and reduced protein rejection. However hypochlorite also seemed to alter the membrane surface properties, causing the protein to form a less permeable layer that reduced the flux of whey.     

GIS-based Methodology for Identification of Suitable Locations for Rainwater Harvesting Structures

Presently, the water resources across the world are being continuously depleted. It is essential to find sustainable solutions for this shortage of water. Rainwater harvesting is one such promising solution to this problem. This paper presents a new GIS-based methodology to identify suitable locations for rainwater harvesting structures using only freely available imageries/remote sensing data and data from other sources. The methodology has been developed for the semi-arid environment of Khushkhera-Bhiwadi-Neemrana Investment Region (KBNIR) in Alwar district of Rajasthan. For identifying locations suitable for rainwater harvesting structures, the layers of surface elevation (ASTER-DEM), landuse/landcover, soil map, drainage map and depression map are used and further analyzed for their depression volume, and availability of surface runoff using Soil Conservation Service - Curve Number (SCS-CN) method. Based on the proposed criteria total seven locations were identified, out of which two locations are excellent; three locations are good, (if provisions of overflow structure are made for them) and two locations are not suitable for rain water harvesting. The total rainwater harvesting potential of the study area is 54.49 million cubic meters which is sufficient to meet the water requirements if harvested and conserved properly. This methodology is time-saving and cost-effective. It can minimize cost of earthwork and can be utilized for the planning of cost effective water resource management.     

X-FEM simulation for two-unequal-collinear cracks in 2-D finite piezoelectric specimen

A study for two-unequal-collinear cracks in a 2-D finite piezoelectric specimen is carried out using a new set of six crack-tip enrichment functions proposed here for piezoelectric media in the X-FEM framework. The intensity factors and energy release rate are calculated using interaction integral in conjugation with the near tip behavior given by the Stroh formalism. Effect of finite size of the specimen is analyzed with respect to offset distances of the cracks from the specimen boundaries. ERR variations are investigated with respect to inter- crack space, crack lengths and electrical/mechanical loadings. Hence, two-unequal-collinear cracks in an infinite domain problem is simulated, analyzed and validated using X-FEM. Further, ERR at the crack tips for the asymmetric case of two collinear equal and unequal cracks, is also computed. It is concluded through this investigation that the proposed enrichment functions could be used to handle the problems of fracture mechanics in 2-D piezoelectric media within a good accuracy.     

A Heat Transfer Model for Firefighters’ Protective Clothing,Continued Developments in Protective Clothing Modeling

In the year 2000, a paper entitled “A Heat Transfer Model for Firefighters’ Protective Clothing” was published in Volume 36, No. 1, of Fire Technology, and it received the 2001 Harry C. Bigglestone Award for Excellence in Written Communication of Fire Protection Concepts from The Fire Protection Research Foundation. Since the publication of this paper, there has been additional development of the heat transfer model. The radiant heat transfer element has been refined, and the model can now address predictions of heat transfer through wet protective clothing materials. Additionally, there has been an extension of the thermal properties database for fabric materials used to manufacture firefighters’ protective clothing. These improvements have significantly expanded the capabilities of the model and provide users with a more robust tool for economically predicting thermal protective clothing performance.     

ON THE IDENTIFICATION OF SOME BILINEAR TIME SERIES MODELS

Abstract. In their book on bilinear time series models Granger and Andersen (1978, p. 43) dismiss the use of third order moments for identifying models on the grounds that for some bilinear models they will all be zero and hence are of no use in discriminating between true white noise and some bilinear models. However, in this paper it is shown that some of the third order moments do not vanish for some superdiagonal and diagonal bilinear models and the pattern of non zero moments can be used to discriminate between true white noise and these bilinear models and also between different bilinear models. Simulation experiments are used to study the applicability of theoretical results.     

Sonochemical effect induced by hydrodynamic cavitation: Comparison of venturi/orifice flow geometries

This study presents comparative assessment of four cavitation devices (three venturis and an orifice) in terms of cavitational yield. A fourfold approach was adopted for assessment, viz. CFD simulations of cavitating flow, simulations of individual cavitation bubble dynamics, high speed photographs of cavitating flow and model reaction of potassium iodide oxidation. Influence of design parameters of cavitation devices on nature of cavitation produced in the flow was studied. Number density of cavitation bubbles in the flow and interactions among bubbles had critical influence on cavitation yield. Orifice gave the highest cavitational yield per unit energy dissipation in flow (despite lower working inlet pressure) due to low density of cavitation bubbles in flow. On contrary, occurrence of large cavitation bubble clouds in venturi flow had adverse effect on cavitational yield due to high interactions among cavitation bubbles resulting in interbubble coalescence and recombination of oxidizing radicals generated from cavitation bubbles. © 2017 American Institute of Chemical Engineers AIChE J, 63: 4705–4716, 2017     

On computing minimal independent support and its applications to sampling and counting

Constrained sampling and counting are two fundamental problems arising in domains ranging from artificial intelligence and security, to hardware and software testing. Recent approaches to approximate solutions for these problems rely on employing SAT solvers and universal hash functions that are typically encoded as XOR constraints of length n/2 for an input formula with n variables. As the runtime performance of SAT solvers heavily depends on the length of XOR constraints, recent research effort has been focused on reduction of length of XOR constraints. Consequently, a notion of Independent Support was proposed, and it was shown that constructing XORs over independent support (if known) can lead to a significant reduction in the length of XOR constraints without losing the theoretical guarantees of sampling and counting algorithms. In this paper, we present the first algorithmic procedure (and a corresponding tool, called MIS) to determine minimal independent support for a given CNF formula by employing a reduction to group minimal unsatisfiable subsets (GMUS). By utilizing minimal independent supports computed by MIS, we provide new tighter bounds on the length of XOR constraints for constrained counting and sampling. Furthermore, the universal hash functions constructed from independent supports computed by MIS provide two to three orders of magnitude performance improvement in state-of-the-art constrained sampling and counting tools, while still retaining theoretical guarantees.