On some generalized ageing orderings

Some partial orderings which compare probability distributions with the expo- nential distribution, are found to be very useful to understand the phenomenon of ageing. Here, we introduce some new generalized partial orderings which de- scribe the same kind of characterization of some generalized ageing classes. We give some equivalent conditions for each of the orderings. Inter-relations among the generalized orderings have also been discussed

Accounting for the effect of heterogeneous plastic deformation on the formability of aluminium and steel sheets

Forming Limit Curves characterise ‘mean’ failure strains of sheet metals. Safety levels from the curves define the deterministic upper limit of the processing and part design window, which can be small for high strength, low formability materials. Effects of heterogeneity of plastic deformation, widely accepted to occur on the microscale, are neglected. Marciniak tests were carried out on aluminium alloys (AA6111-T4, NG5754-O), dual-phase steel (DP600) and mild steel (MS3). Digital image correlation was used to measure the effect of heterogeneity on failure. Heterogeneity, based on strain variance was modelled with the 2-component Gaussian Mixture Model and a framework was proposed to 1) identify the onset of necking and to 2) re-define formability as a probability to failure. The result were ‘forming maps’ in major-minor strain space of contours of constant probability (from probability, P=0 to P=1), which showed how failure risk increased with major strain. The contour bands indicated the unique degree of heterogeneity in each material. NG5754-O had the greatest width (0.07 strain) in plane strain and MS3 the lowest (0.03 strain). This novel characterisation will allow engineers to balance a desired forming window for a component design with the risk to failure of the material

Evaluation of diagnostic efficacy of hepatobiliary scintigraphy as a diagnostic procedure in pediatric practice with special reference to cholestatic jaundice

Background: The objective was to assess the diagnostic efficacy of hepatobiliary scintigraphy (Tc99 mebrofenin) in case of cholestatic jaundice in pediatric practice.Method: Study conducted on 45 cases from 0-6 yrs. of age. Out of 45 pt 20 pt excluded from study Hepatobiliary Scintigraphy (Tc99m Mebrofinin) was performed in 25 cases. Injection of Tc99m mebrofinin (1-2 mCi) IV was given to each subject. Dynamic hepatic scan was done upto initial 1 hour study and additional delayed images were taken at 4 & 24 hrs only in case of non-visualization of tracer in the intestine after initial 1 hr. study.Results: In this study hepatobiliary scintigraphy was 100% sensitive, 93.73% specific, 80% positive predictive values, 100% negative predictive value, 6.23% false positive result and virtually no false negative result for biliary atresia. Conclusion: It is concluded that Tc99m mebrofenin hepatobiliary scintigraphy has proven to be reliable noninvasive imaging modality in evaluating cholestatic jaundice in pediatric practice as it carries a high sensitive & specific value, good positive & no negative predictive value, few false positive & virtually no false negative results.

Microstructural anisotropy at the ion-induced rippled amorphouscrystalline interface of silicon

Using grazing-incidence X-ray scattering technique the authors have investigated the evolution of the damage profile of the transition layer between the ion-induced ripplelike pattern on top surface and the ripples at buried crystalline interface in silicon created after irradiation with 60 keV Ar+ ions under 60°. The transition layer consists of a defect-rich crystalline part and a complete amorphous part. The crystalline regions are highly strained but relaxed for low dose and high dose irradiations, respectively. The appearance of texture in both cases shows that the damage of the initial crystalline structure by the ion bombardment takes place along particular crystallographic directions

Characterization of Tsunami and Palaeo-tsunami deposits in the Neil Island, South Andaman, India

The nature of tsunamigenic and palaeo-tsunamigenic sediments in Neil Island, deposited by the great Indian Ocean in 2004 is documented herein. Pit, trench and core samples were collected from the four beaches, namely, Bharatpur, Ramnagar, Sitapur and Lakshmanpur; which exhibit distinguished anomalies in the sedimentological parameters, viz. skewness, kurtosis and standard deviation at various depths. The palaeontological study shows the simultaneous occurrence of characteristic benthic taxa of near-shore environment and upper part of continental slope along with the open ocean dweller planktic foraminifera- an intermixed foraminiferal assemblage is mainly due to the tsunami wave actions. The multiproxy approach reveals the occurrence of the tsunami and palaeo-tsunami deposits in Neil Island from 9 to 40 cm and below 60 cm depth, respectively

Synthesis of unnatural hydroxyanthraquinones: Experiments towards total synthesis of pradimicinone

126-13

BINGO: A code for the efficient computation of the scalar bi-spectrum

We present a new and accurate Fortran code, the BI-spectra and Non-Gaussianity Operator (BINGO), for the efficient numerical computation of the scalar bi-spectrum and the non-Gaussianity parameter f_{NL} in single field inflationary models involving the canonical scalar field. The code can calculate all the different contributions to the bi-spectrum and the parameter f_{NL} for an arbitrary triangular configuration of the wavevectors. Focusing firstly on the equilateral limit, we illustrate the accuracy of BINGO by comparing the results from the code with the spectral dependence of the bi-spectrum expected in power law inflation. Then, considering an arbitrary triangular configuration, we contrast the numerical results with the analytical expression available in the slow roll limit, for, say, the case of the conventional quadratic potential. Considering a non-trivial scenario involving deviations from slow roll, we compare the results from the code with the analytical results that have recently been obtained in the case of the Starobinsky model in the equilateral limit. As an immediate application, we utilize BINGO to examine of the power of the non-Gaussianity parameter f_{NL} to discriminate between various inflationary models that admit departures from slow roll and lead to similar features in the scalar power spectrum. We close with a summary and discussion on the implications of the results we obtain.Comment: v1: 5 pages, 5 figures; v2: 35 pages, 11 figures, title changed, extensively revised; v3: 36 pages, 11 figures, to appear in JCAP. The BINGO code is available online at http://www.physics.iitm.ac.in/~sriram/bingo/bingo.htm

Observation of Néel-type skyrmions in acentric self-intercalated Cr_1+δTe₂

Transition-metal dichalcogenides intercalated with 3d-transition metals within the van der Waals (vdW) gaps have been the focus of intense investigations owing to their fascinating structural and magnetic properties. At certain concentrations the intercalated atoms form ordered superstructures that exhibit ferromagnetic or anti-ferromagnetic ordering. Here we show that the self-intercalated compound Cr1+δTe2 with δ ≈ 0.3 exhibits a new, so far unseen, three-dimensionally ordered (2×2×2) superstructure. Furthermore, high resolution X-ray diffraction reveals that there is an asymmetric occupation of the two inequivalent vdW gaps in the unit cell. The structure thus lacks inversion symmetry, which, thereby, allows for chiral non-collinear magnetic nanostructures. Indeed, Néel-type skyrmions are directly observed using Lorentz transmission electron microscopy. The skyrmions are stable within the accessible temperature range (100–200 K) as well as in zero magnetic field. The diameter of the Néel skyrmions increases with lamella thickness and varies with applied magnetic field, indicating the role of long-range dipole fields. Our studies show that self-intercalation in vdW materials is a novel route to the formation of synthetic non-collinear spin textures

NASAs Seasonal Hydrological Forecast System for Improved Food Insecurity Early Warning in Africa

To develop a seasonal scale drought forecasting system to strengthen FEWS NET's progressive early warning efforts in Africa and the Middle East. This presentation provides an overview of the implementation, validation, and ongoing operational applications of this system