Microwave assisted hydrothermal synthesis of well-dispersed and thermally stable Ag@SnO2 core–shell nanocomposites for propane sensing applications

A simple microwave assisted hydrothermal precipitation (M–H) technique for the synthesis of Ag@SnO₂ core–shell structure nanoparticles (NPs) is reported. Ag NPs were synthesized via chemical reduction of metal salt followed by M–H deposition of tin dioxide shell for fabrication of monodispersed core–shell particles. The phase and morphology has been investigated by X-ray diffraction technique (XRD) and transmission electron microscopy (TEM) respectively. Ag@SnO₂ core–shell nanocomposites have shown distinct surface Plasmon spectrum in the range of 407–440 nm. The core–shell morphology is confirmed from the TEM images. XRD patterns have suggested the formation of silver and tin dioxide in the face-centered cubic and Cassiterite form respectively. Our investigations suggested that the formation of core–shell structure results in the enhanced thermal stability of the system. Synthesized material is used for the detection of propane gas. To understand the multi gas sensing ability and selectivity for detection of propane gas by Ag@SnO₂ core–shell materials based devices, Sinha–Tripathy soft-sensor model has been proposed.     

The Economics of Urban Water Demand: The Case of Industrial and Commercial Water Use in Hawaii

The industrial and commercial establishments of the City and County of Honolulu (CCH) have increased their water consumption dramatically in recent years. This study examined water use in the food-processing industry, non-food processing industries, and the commercial sector in relation to price of water and output/sales of the industrial or commercial unit. The generalized least-squares (GLS) procedure was used to estimate the regression equations, although the results of ordinary least-squares(OLS) estimation are also presented. The study results showed sensitivity of water use in relation to price level in the case of the food-processingindustry and insensitivity in the non-food processing and commercial establishments. Analogous results were found with respect to water use and number of employees.     

Investigation of Deformation Behavior of Ring-Tensile Specimens Machined from Pressure Tubes of Indian PHWR

Specimens machined in the form of circular rings directly from the nuclear reactor pressure tubes and tested in a ring-tension test-setup offer great simplicity in evaluating the transverse mechanical properties of the as-manufactured as well as those of the service-exposed tubes. However, the state of stress in the specimen cross-section is not purely uni-axial due to the effect of bending and the presence of lateral pressure due to the loading mandrel. This requires the use of 3-D finite element (FE) analysis for simulation of deformation behavior of the specimens in the ring-tension test-setup. In this work, we have analyzed the deformation behavior of ring-tension specimens machined from two different types of zirconium alloy pressure tubes as used in the Indian pressurized heavy water reactors. The effect of geometry of the loading mandrel (i.e., 2-piece vs. 3-piece type of mandrel) on the load-deformation behavior of the test-setup has been studied. It was observed that the values of maximum load as well as the deformation behavior in the post-necking region differ significantly when only the geometry of the loading mandrel is changed keeping all the other parameters same. FE analysis has been able to correctly predict these variations as it takes into account of the effect of geometry, material properties as well the interaction between the mandrel and the specimen. Hence, the use of FE method is essential in the inverse analysis procedure where the material properties can be determined from these complex test-setups.     

Modeling of Cu-linked rectification devices by varying torsion angles

Using the nonequilibrium Green’s function (NEGF) method in combination with the density functional theory (DFT), we have analyzed the rectifying performance in Cu-linked molecular devices by varying torsion angles (φ=0^°–90^°). The linking effect of Cu atom has been investigated by calculating current-voltage (I-V) characteristics, rectification performance, transmission functions, projected density of states (PDOS), and molecular projected self-consistent Hamiltonian (MPSH). Present calculations revealed that linking of Cu in combination with conjugated dithiocarboxylate (-CS₂) and standard thiol linkers significantly affects the metal-molecule coupling asymmetry, and thus the rectifying behavior in molecular devices. Further, the subsequent studies show that the left-right combination of -CS₂ linker and Cu atom displays higher rectification ratio at various torsion angles in gold–biphenyl–gold junctions than thiol and Cu linkers. The calculated results are helpful not only in predicting an optimal combination of linking groups for realistic applications but also provide the way for better control of rectification effects in molecular devices.     

Recycling of waste PET‐bottles using dimethyl sulfoxide and hydrotalcite catalyst

The degradation of PET bottles has been successfully achieved using hydrotalcite as catalyst and dimethyl sulfoxide (DMSO) as solvent. The reaction was carried out at boiling point of DMSO (190°C) and degradation was complete in 10 min. The oligomer (tetramer) obtained was treated with NaOH at room temperature in methanol to get dimethyl terephthalate (DMT) and ethylene glycol (EG). Thus, it is a safe and cleaner process. Oligomer was characterized by MS, 13 C‐NMR, X‐ray diffractometric, and thermogravimetric analysis. DMT and EG were characterized by GC‐MS. DMT was also characterized by FT‐IR. GC‐MS analysis shows that the purity of DMT was 99%. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2012     

Ferromagnetic resonance in metallic glasses: study of fracture,stress and thermal stability

Effects of fracture, stress and isothermal annealing of Fe-Ni based metallic glasses have been investigated using the ferromagnetic resonance technique.fmr linewidth is quite sensitive to changes in the magnetic and structural order in metallic glasses, andfmr lineshape seems to provide useful qualitative information on the mechanical state of these systems. Our observations are compared with recent work of Baianu and co-workers.     

Accord: a programming framework for autonomic applications

The emergence of pervasive wide-area distributed computing environments, such as pervasive information systems and computational grids, has enabled new generations of applications that are based on seamless access, aggregation, and interaction. However, the inherent complexity, heterogeneity, and dynamism of these systems require a change in how the applications are developed and managed. In this paper, we present a programming framework that extends existing programming models/frameworks to support the development of autonomic self-managing applications. The framework enables the development of autonomic elements and the formulation of autonomic applications as the dynamic composition of autonomic elements. The operation of the proposed framework is illustrated using a forest fire management application.     

Models, methods and middleware for grid-enabled multiphysics oil reservoir management

Meeting the demands for energy entails a better understanding and characterization of the fundamental processes of reservoirs and of how human made objects affect these systems. The need to perform extensive reservoir studies for either uncertainty assessment or optimal exploitation plans brings up demands of computing power and data management in a more pervasive way. This work focuses on high performance numerical methods, tools and grid-enabled middleware systems for scalable and data-driven computations for multiphysics simulation and decision-making processes in integrated multiphase flow applications. The proposed suite of tools and systems consists of (1) a scalable reservoir simulator, (2) novel stochastic optimization algorithms, (3) decentralized autonomic grid middleware tools, and (4) middleware systems for large-scale data storage, querying, and retrieval. The aforementioned components offer enormous potential for performing data-driven studies and efficient execution of complex, large-scale reservoir models in a collaborative environment.     

The Place of Housing Stability in HIV Research: A Critical Review of the Literature

There exists a wealth of literature investigating the association between housing stability and the health of people living with, or at risk of acquiring, HIV. Following a review of the limitations of prevailing housing status measures, the concepts underlying definitions of housing status in HIV literature are presented. This review concludes by proposing a conceptual shift away from understanding housing as a predominantly material entity towards a more holistic understanding of the social and cultural importance people place on home, and various spaces people find and make “home”. Addressing the varied housing needs of people living with, and at risk of, HIV relies on a more careful consideration of context, and a commitment to cultivating and supporting spaces which allow people to manage their health and well-being.     

Multiscale Model to Study of Fracture Toughening in Graphene/Polymer Nanocomposite

The aim of this letter is to study the fracture toughening in graphene/polymer nanocomposites. Finite element based multiscale model was developed for the proposed study; where graphene is modeled in atomistic scale, whereas displacement and stresses in polymer is modeled in continuum phase. 3D virtual crack closure technique in conjunction with the proposed multiscale model was employed to study the fracturetoughening in graphene/polymer nanocomposites.