Variability of seismic response of soils using stochastic finite element method

The evaluation of seismic response of soil sites constitutes an important problem with respect to groundmotion amplification and soil instability because of liquefaction. The base motion generated during earthquake is a random process. In addition, the soil sites are usually homogenous with randomly varying characteristics. The uncertainties associated with the input motion and site characteristics may lead to a wide range of variability of the site response. In this paper, a Monte-Carlo based stochastic finite element method is used to study the variability of seismic response.     

Wave-induced response of seabed: Various formulations and their applicability

In this study, a set of generalized analytical solutions are developed for the wave-induced response of a saturated porous seabed under plane strain condition. When considering the water waves originating in deep water and travelling towards the shore, their velocities, lengths and heights vary. Depending on the characteristics of the wave and the properties of the seabed, different formulations (fully dynamic, partly dynamic, quasi-static) for the wave-induced response of the seabed are possible. The solutions for the response with these formulations are established in terms of non-dimensional parameters. The results are presented in terms of pore pressure, shear stress and vertical effective stress distributions within the seabed. For typical values of wave period and seabed permeability, the regions of applicability of the three formulations are identified and plotted in parametric spaces. With given wave and seabed characteristics, these regions provide quick identification of the appropriate formulation for an adequate evaluation of the wave-induced seabed response.     

An unusual occurrence of coesite at the Lonar crater,India

Coesite has been identified within ejected blocks of shocked basalt at Lonar crater, India. This is the first report of coesite from the Lonar crater. Coesite occurs within SiO₂ glass as distinct ~30 μm spherical aggregates of “granular coesite” identifiable both with optical petrography and with micro‐Raman spectroscopy. The coesite+glass occurs only within former silica amygdules, which is also the first report of high‐pressure polymorphs forming from a shocked secondary mineral. Detailed petrography and NMR spectroscopy suggest that the coesite crystallized directly from a localized SiO₂ melt, as the result of complex interactions between the shock wave and these vesicle fillings.     

Optimizing the Determination of Roughness Parameters for Model Urban Canopies

We present an objective optimization procedure to determine the roughness parameters for very rough boundary-layer flow over model urban canopies. For neutral stratification the mean velocity profile above a model urban canopy is described by the logarithmic law together with the set of roughness parameters of displacement height d, roughness length \(z_0\), and friction velocity \(u_*\). Traditionally, values of these roughness parameters are obtained by fitting the logarithmic law through (all) the data points comprising the velocity profile. The new procedure generates unique velocity profiles from subsets or combinations of the data points of the original velocity profile, after which all possible profiles are examined. Each of the generated profiles is fitted to the logarithmic law for a sequence of values of d, with the representative value of d obtained from the minima of the summed least-squares errors for all the generated profiles. The representative values of \(z_0\) and \(u_*\) are identified by the peak in the bivariate histogram of \(z_0\) and \(u_*\). The methodology has been verified against laboratory datasets of flow above model urban canopies.     

Rare Earth and Other Trace Element Content of NRCC HISS-1 Sandy Marine Sediment Reference Material

The National Research Council (NRC), Ottawa, Canada sandy marine sediment reference material HISS-1 was characterised for thirty-seven trace elements by neutron activation optimised irradiation, cooling and counting protocols using the low power Miniature Neutron Source Reactor (MNSR) as a neutron source. This INAA methodology quantified twenty additional elements including ten rare earth (Ce, Dy, Eu, Ho, La, Lu, Nd, Sm, Tb and Yb) and ten other elements (Ba, Br, Cs, Ga, Hf, Rb, Sc, Ta, Th and Zr) missing in the final NRCC certification. A large number of values produced by different irradiation schemes together with the use of certified reference materials in the quantification step that showed good precision, provided confidence in the results. The reliability of the REE data was checked by plotting chondrite-normalised graphs.     

A critical review on waste paper sorting techniques

Efficient waste paper recycling has a significant role in the sustainable environment. Recyclable waste paper as a fundamental ingredient of municipal solid wastes (MSWs) is indeed an “urban ore”. Waste papers are considered as the solid recovered fuel which is recovered from MSW. Recyclable waste papers are segregated into various grades to produce high-quality products. Moreover, sorted paper streams save energy, chemicals, and water, as well as reduce sludge and rejects. Information technology is widely integrated with the waste management industry into its operations such as recycling, reuse, segregating based on categories and so on. This review article focuses on the life cycle of waste paper and existing waste paper sorting techniques. In the paper industry, many types of sensors are used in different mechanical and optical waste paper sorting systems. Such sensors include lignin, gloss, stiffness, mid-infrared, infrared, and color sensors. In this review, also described the effectiveness of different waste paper sorting systems, and finally, recommended appropriate waste paper sorting techniques based on effectiveness and low-cost implementation.     

Search for TeV gamma-rays from Geminga pulsar

We present the results of observation of the Geminga pulsar carried out in the TeV energy band during the 6 year period spanning 2000–2006 using the Pachmarhi Array of Cherenkov Telescopes (PACT). A long stretch of data, new computer codes and the “Tempo” package have been used in the present analysis. We have searched for evidence of pulsed emission of γ-rays from the Geminga pulsar using the post-glitch pulsar elements obtained by Jackson and Halpern from X-ray/γ-ray satellite data. We do not see any significant evidence for pulsed emission from the Geminga pulsar at a threshold energy of 825 GeV. In this paper we present our results on the light curve in the TeV energy band, set an upper limit on the time averaged flux of γ-rays, and compare our results with other ground based observations.