A generalized geo-hazard warning system

An automated geo-hazard warning system is the need of the hour. It is integration of automation in hazard evaluation and warning communication. The primary objective of this paper is to explain a geo-hazard warning system based on Internet-resident concept and available cellular mobile infrastructure that makes use of geo-spatial data. The functionality of the system is modular in architecture having input, understanding, expert, output and warning modules. Thus, the system provides flexibility in integration between different types of hazard evaluation and communication systems leading to a generalized hazard warning system. The developed system has been validated for landslide hazard in Indian conditions. It has been realized through utilization of landslide causative factors, rainfall forecast from NASA's TRMM (Tropical Rainfall Measuring Mission) and knowledge base of landslide hazard intensity map and invokes the warning as warranted. The system evaluated hazard commensurate with expert evaluation within 5-6 % variability, and the warning message permeability has been found to be virtually instantaneous, with a maximum time lag recorded as 50 s, minimum of 10 s. So it could be concluded that a novel and stand-alone system for dynamic hazard warning has been developed and implemented. Such a handy system could be very useful in a densely populated country where people are unaware of the impending hazard.

Data acquisition and processing at ocean bottom for a Tsunami warning system

The design and development of a Bottom Pressure Recorder for a Tsunami Early Warning System is described here. The special requirements that it should satisfy for the specific application of deployment at ocean bed and pressure monitoring of the water column above are dealt with. A high-resolution data digitization and low circuit power consumption are typical ones. The implementation details of the data sensing and acquisition part to meet these are also brought out. The data processing part typically encompasses a Tsunami detection algorithm that should detect an event of significance in the background of a variety of periodic and aperiodic noise signals. Such an algorithm and its simulation are presented. Further, the results of sea trials carried out on the system off the Chennai coast are presented. The high quality and fidelity of the data prove that the system design is robust despite its low cost and with suitable augmentations, is ready for a full-fledged deployment at ocean bed. (C) 2013 Elsevier Ltd. All rights reserved.

Review of Geohazard Warning Systems toward Development of a Popular Usage Geohazard Warning Communication System

The advent and evolution of geohazard warning systems is a very interesting study. The two broad fields that are immediately visible are that of geohazard evaluation and subsequent warning dissemination. Evidently, the latter field lacks any systematic study or standards. Arbitrarily organized and vague data and information on warning techniques create confusion and indecision. The purpose of this review is to try and systematize the available bulk of information on warning systems so that meaningful insights can be derived through decidable flowcharts, and a developmental process can be undertaken. Hence, the methods and technologies for numerous geohazard warning systems have been assessed by putting them into suitable categories for better understanding of possible ways to analyze their efficacy as well as shortcomings. By establishing a classification scheme based on extent, control, time period, and advancements in technology, the geohazard warning systems available in any literature could be comprehensively analyzed and evaluated. Although major advancements have taken place in geohazard warning systems in recent times, they have been lacking a complete purpose. Some systems just assess the hazard and wait for other means to communicate, and some are designed only for communication and wait for the hazard information to be provided, which usually is after the mishap. Primarily, systems are left at the mercy of administrators and service providers and are not in real time. An integrated hazard evaluation and warning dissemination system could solve this problem. Warning systems have also suffered from complexity of nature, requirement of expert-level monitoring, extensive and dedicated infrastructural setups, and so on. The user community, which would greatly appreciate having a convenient, fast, and generalized warning methodology, is surveyed in this review. The review concludes with the future scope of research in the field of hazard warning systems and some suggestions for developing an efficient mechanism toward the development of an automated integrated geohazard warning system. DOI: 10.1061/(ASCE)NH.1527-6996.0000078. (C) 2012 American Society of Civil Engineers.

Effect of Rayleigh numbers on the evolution of double-diffusive salt fingers

This is a transient two-dimensional numerical study of double-diffusive salt fingers in a two-layer heat-salt system for a wide range of initial density stability ratio (R-rho 0) and thermal Rayleigh numbers (Ra-T similar to 10(3) - 10(11)). Salt fingers have been studied for several decades now, but several perplexing features of this rich and complex system remain unexplained. The work in question studies this problem and shows the morphological variation in fingers from low to high thermal Rayleigh numbers, which have been missed by the previous investigators. Considerable variations in convective structures and evolution pattern were observed in the range of Ra-T used in the simulation. Evolution of salt fingers was studied by monitoring the finger structures, kinetic energy, vertical profiles, velocity fields, and transient variation of R-rho(t). The results show that large scale convection that limits the finger length was observed only at high Rayleigh numbers. The transition from nonlinear to linear convection occurs at about Ra-T similar to 10(8). Contrary to the popular notion, R-rho(t) first decrease during diffusion before the onset time and then increase when convection begins at the interface. Decrease in R-rho(t) is substantial at low Ra-T and it decreases even below unity resulting in overturning of the system. Interestingly, all the finger system passes through the same state before the onset of convection irrespective of Rayleigh number and density stability ratio of the system. (C) 2014 AIP Publishing LLC.

Rational molecular dynamics scheme for predicting optimum concentration loading of nano-additive in phase change materials

The present study deals with the diffusion and phase transition behaviour of paraffin reinforced with carbon nano-additives namely graphene oxide (GO) and surface functionalized single walled carbon nanotubes (SWCNT). Bulk disordered systems of paraffin hydrocarbons impregnated with carbon nano-additives have been generated in realistic equilibrium conformations for potential application as latent heat storage systems. Ab initio molecular dynamics(MD) in conjugation with COMPASS forcefield has been implemented using periodic boundary conditions. The proposed scheme allows determination of optimum nano-additive loading for improving thermo-physical properties through analysis of mass, thermal and transport properties; and assists in determination of composite behaviour and related performance from microscopic point of view. It was observed that nanocomposites containing 7.8% surface functionalised SWCNT and 55% GO loading corresponds to best latent heat storage system. The propounded methodology could serve as a by-pass route for economically taxing and iterative experimental procedures required to attain the optimum composition for best performance. The results also hint at the large unexplored potential of ab-initio classical MD techniques for predicting performance of new nanocomposites for potential phase change material applications. (C) 2015 Author(s).

Integral isobaric heat of vaporization of benzene-1,2-dichloroethane system

Abstract is not available.

An analysis of MONTBLEX data on heat and momentum flux at Jodhpur

Parameterization of sensible heat and momentum fluxes as inferred from an analysis of tower observations archived during MONTBLEX-90 at Jodhpur is proposed, both in terms of standard exchange coefficients C-H and C-D respectively and also according to free convection scaling. Both coefficients increase rapidly at low winds (the latter more strongly) and with increasing instability. All the sensible heat flux data at Jodhpur (wind speed at 10m <(U)over bar (10)>, < 8ms(-1)) also obey free convection scaling, with the flux proportional to the '4/3' power of an appropriate temperature difference such as that between 1 and 30 m. Furthermore, for <(U)over bar (10)> < 4 ms(-1) the momentum flux displays a linear dependence on wind speed.

Phase Equilibria in the System $Al_{2}O_{3}-CaO-CoO$ and Gibbs Energy of Formation of $Ca_{3}CoAl_{4}O_{10}$

The floating-zone method with different growth ambiences has been used to selectively obtain hexagonal or orthorhombic DyMnO3 single crystals. The crystals were characterized by x-ray powder diffraction of ground specimens and a structure refinement as well as electron diffraction. We report magnetic susceptibility, magnetization and specific heat studies of this multiferroic compound in both the hexagonal and the orthorhombic structure. The hexagonal DyMnO3 shows magnetic ordering of Mn3+ (S = 2) spins on a triangular Mn lattice at T-N(Mn) = 57 K characterized by a cusp in the specific heat. This transition is not apparent in the magnetic susceptibility due to the frustration on the Mn triangular lattice and the dominating paramagnetic susceptibility of the Dy3+ (S = 9/2) spins. At T-N(Dy) = 3 K, a partial antiferromagnetic order of Dy moments has been observed. In comparison, the magnetic data for orthorhombic DyMnO3 display three transitions. The data broadly agree with results from earlier neutron diffraction experiments, which allows for the following assignment: a transition from an incommensurate antiferromagnetic ordering of Mn3+ spins at T-N(Mn) = 39 K, a lock-in transition at Tlock-in = 16 K and a second antiferromagnetic transition at T-N(Dy) = 5 K due to the ordering of Dy moments. Both the hexagonal and the orthorhombic crystals show magnetic anisotropy and complex magnetic properties due to 4f-4f and 4f-3d couplings.

A Closed-Cycle Refrigerator Based Pulsed Management System

A low cost 12 T pulsed magnet system has been integrated with a closed-cycle helium refrigerator. The copper solenoid is directly immersed in liquid nitrogen for reduced electrical resistance and more efficient heat transfer. This ensures a minimal delay of few minutes between pulses. The sample is mounted on the cold finger of the refrigerator and, along with the surrounding vacuum shroud, is inserted into the bore of the solenoid. When combined with software lock-in signal processing to reduce noise, quick but accurate measurements can be performed at temperatures 4 K-300 K up to 12 T. Quantum Hall effect data in a p-channel SiGe/Si heterostructure has been used to calibrate the instrument against a commercial superconducting magnet. Its versatility as a routine characterization tool is demonstrated bymeasuring parallel conduction in Si/SiGe modulation doped heterostructures.

Glass Formation in the Ternary Sulphate System, K2S04-Na2S04-ZnS04

Glasses have been prepared by conventional quenching techniques in the ternary sulphate system KzSO4-Na2SO4-ZnSO4, in the range 30-80 % ZnS04. The proportions of alkali sulphates in the glass have been varied widely. The glass formation region has been delineated and densities, refractive indices and microhardnesses have been measured. The heat capacities of the glasses have been measured over a wide range of temperature by differential scanning calorimetry. The effect of composition on molar volume, molar polarization and glass transition have been explained on the basis of a random close-packing model.

Optical Properties of Nanocrystalline Potassium Lithium Niobate in the Glass System (100-x) TeO2-x(1.5K(2)O-Li2O-2.5Nb(2)O(5))

Optically clear glasses of various compositions in the system (100-x) TeO2-x(1.5K(2)O-Li2O-2.5Nb(2)O(5)) (2 <= x <= 12, in molar ratio) were prepared by the melt-quenching technique. The glassy nature of the as-quenched samples was established via differential scanning calorimetry (DSC). The amorphous and the crystalline nature of the as-quenched and heat-treated samples were confirmed by the X-ray powder diffraction and transmission electron microscopic (TEM) studies. Transparent glasses comprising potassium lithium niobate (K3Li2Nb5O15) microcrystallites on the surface and nanocrystallites within the glass were obtained by controlled heat-treatment of the as-quenched glasses just above the glass transition temperature (T-g). The optical transmission spectra of these glasses and glass-crystal composites of various compositions were recorded in the 200-2500 nm wavelength range. Various optical parameters such as optical band gap, Urbach energy, refractive index were determined. Second order optical non-linearity was established in the heat-treated samples by employing the Maker-Fringe method.

Investigations Of Glasses In The System Pbo-Pbf2

Glass formation in the system PbO–PbF2 has been investigated. The structure of these glasses has been studied using X-ray diffraction. Densities, heat capacities, glass-transition and crystallization temperatures and Vicker's microhardnesses have been measured. D.c. conductivities of these glasses have also been measured as a function of temperature. A structural model has been developed which suggests the existence of [PbO2F4]-type units over the entire composition range. It is suggested that covalent linkages of the type—O—Pb—O— play a crucial role in determining the composition limits to glass formation. The structural model has been shown to be consistent with other physical properties of the glasses.

Combustion and Thermal Decomposition of a Binary Oxidiser System: Ammonium Perchlorate-Potassium Perchlorate

Combustion behaviour of ammonium perchlorate-potassium perchlorate pellets is studied using Crawford strand burners. At low concentrations of potassium perchlorate (up to 30 percent potassium perchlorate) the burning rate of ammonium perchlorate-potassium perchlorate condensed mixtures increases with potassium perchlorate content. Above 40 percent potassium perchlorate content, combustion sustenance becomes difficult. Decomposition products of ammonium perchlorate sensitize the melting and subsequent decomposition of potassium perchlorate. The results are explained in terms of the melt layer thickness, flame temperature and the resultant surface temperature, and heat wave penetration into the solid. The study suggests the importance of melt layer on the burning surface in the deflagration behaviour of ammonium perchlorate-potassium perchlorate condensed mixtures

The heat capacity of liquid carbon disulfide + acetonitrile, especially near the upper critical solution temperature

The heat capacity Cp of the binary liquid system CS2 + CH3CN has been studied. This system has an upper critical solution temperature To ≈ 323.4 K and a critical mole fraction of CS2xo ≈ 0.5920. Measurements were made both for mixtures close to and far away from the critical region. The heat capacity of the mixture with x = xo exhibits a symmetric logarithmic anomaly around Tc, which is apparently preserved even for compositions in the immediate vicinity of xc. For compositions far away from xc, only a normal rise in Cp over the covered temperature range is observed.