Evaluation of Liquefaction Potential for an Earth Dam Site

The foundation of the proposed Polavaram Earth and Rockfill Dam (India) has a sand deposit about 15 to 30 meters deep. The medium size sand is poorly to uniformly graded having relati.ve density in the range of 40-45% and angle of internal friction 30°. Standard Penetration Tests have been conducted in 22 bore holes at site and the N-counts have been observed to range between 4 to 111. The liquefaction potential of deposit under maximum credible earthquake (MCE) for the site has been evaluated by analyzing the data on the basis of prevailing empirical approaches and by the results of the experiments conducted on the sand in laboratory. The results of the analyses indicate that for the design earthquake the liquefaction would occur at some spots where N-counts are very low. The experiments have been conducted by depositing the sand, with the relative density close to that at site, in a box placed on a shaking table. The table was subjected to equivalent number of sinusoidal cycles corresponding to 75, 65 and 50% level of maximum acceleration of the time history of the design earthquake. As the dam provides an overburden pressure to the foundation, experiments have been conducted with loading on sand deposit in the shake table. The effect of frequency of motion has also been observed. The results of these experiments show that for the design acceleration levels of 0.1 g (65% of maximum acceleration) the maximum pore water pressure would be 31% of the effective overburden. The frequency of 3 cps seems the optimum frequency for generation of pore water pressure and at 8 cps this is less by about 20 percent. Thus the experiments indicate only partial loss of shear strength and not the total liquefaction of the foundation sand

The role of diagnostic hysteroscopy in abnormal uterine bleeding and its histopathological correlation following blind dilatation and curettage

Background: Abnormal uterine bleeding (AUB) is a common gynecological disorder in women. To render appropriate treatment it is vital to establish the correct diagnosis, in this backdrop we have studied the utility of hysteroscopy as a diagnostic procedure against a blind dilatation and curettage. The objectives of the study were hysteroscopic evaluation of abnormal uterine bleeding in reproductive and post-menopausal women. Hysteroscopic findings were compared with the histopathological reports following blind dilatation and curettage.Methods: It is a prospective study on women with symptoms of AUB for a period of one year from Oct 2014 to Nov 2015. Detailed history and clinical examination with an ultrasound (USG) of pelvis to see for endometrial thickness and any structural abnormality was done. 50 cases were included for hysteroscopy. Endometrial biopsy was taken by blind dilation and curettage (D & C) and sent for histopathological examination (HPE). The hysteroscopic and histopathological findings were analyzed.Results: Both hysteroscopy and (D & C) were accurate when an abnormality was diagnosed, giving a specificity of 96.4% and 96.4% respectively and positive predictive value of (95.2% versus 94.4%). The ability to diagnose a lesion was more with hysteroscopy i.e. sensitivity in comparison to curettage, (90.9% versus 77.4%), while a negative diagnosis was less wrongly made with hysteroscopy in comparison to curettage (false negative rate: 9.1% versus 22.7%). In intracavitary lesions like polyp, hysteroscopy gave 100% accuracy.Conclusions: Hysteroscopy is a sensitive diagnostic procedure that provides useful information in all intracavitary lesions and has a higher sensitivity and specificity. A blind D & C for AUB may miss focal lesions including endometrial carcinoma, hence hysteroscopy is advisable

Preparation and characterization of epitaxial Fe2-xTixO3 films with various Ti concentrations (0.5 < x < 1.0)

An ilmenite-hematite solid solution ( Fe2-xTixO3 ) is one of the candidates for practical magnetic semiconductors with a high Curie temperature. We have prepared well-crystallized epitaxial Fe2-xTixO3 films with a wide range of Ti concentrations - x=0.50, 0.60, 0.65, 0.76, 0.87, and 0.94 - on &#945;-Al2O3(001) substrates. The films are prepared by a reactive helicon plasma sputtering technique to evaporate Fe and TiO targets simultaneously under optimized oxygen pressure conditions. The structural characterizations of the films reveal that all films have a single phase of the ordered structure with R3 symmetry, where Ti-rich and Fe-rich layers are stacked alternately along the c axis. All films have large ferrimagnetic moments at low temperature, and room temperature magnetization is clearly observed at x&#60;0.7. The inverse temperature dependence of the resistivities of the films indicates their semiconducting behavior. The film resistivities decrease with decreasing Ti concentration.</p

Role of multiple subband renormalization in the electronic transport of correlated oxide superlattices

Metallic behavior of band-insulator/ Mott-insulator interfaces was observed in artificial perovskite superlattices such as in nanoscale SrTiO3/LaTiO3 multilayers. Applying a semiclassical perspective to the parallel electronic transport we identify two major ingredients relevant for such systems: i) the quantum confinement of the conduction electrons (superlattice modulation) leads to a complex, quasi-two dimensional subband structure with both hole- and electron-like Fermi surfaces. ii) strong electron-electron interaction requires a substantial renormalization of the quasi-particle dispersion. We characterize this renormalization by two sets of parameters, namely, the quasi-particle weight and the induced particle-hole asymmetry of each partially filled subband. In our study, the quasi-particle dispersion is calculated self-consistently as function of microscopic parameters using the slave-boson mean-field approximation introduced by Kotliar and Ruckenstein. We discuss the consequences of strong local correlations on the normal-state free-carrier response in the optical conductivity and on the thermoelectric effects.Comment: 11 pages, 4 figure

Size dependent magnetic properties and cation inversion in chemically synthesized MnFe2O4 nanoparticles

MnFe2O4nanoparticles with diameters ranging from about 4to50nm were synthesized using a modified coprecipitation method. X-ray diffractograms revealed a pure phase spinel ferrite structure for all samples. Transmission electron microscopy showed that the particles consist of a mixture of both spherical (smaller) and cubic (larger) particles dictated by the reaction kinetics. The Néel temperatures (TN) of MnFe2O4 for various particle sizes were determined by using high temperature magnetometry. The ∼4nm MnFe2O4 particles showed a TN of about 320°C whereas the ∼50nm particles had a TN of about 400°C. The high Néel temperature, compared with the bulk MnFe2O4 TN of 300°C, is due to a change in cation distribution between the tetrahedral and octahedral sites of the spinel lattice. Results of extended x-ray absorption fine structure measurements indicate a systematic change in the cation distribution dependent on processing conditions

Detection of Defects on Cold Rolling Mill (CRM) Rolls with Ultrasonic and Eddy Current Flaw Dectors

The service induced defects in CRM rolls, due to them being subjected to complex mechanical & thermal stresses in cold rolling of steel strips or coils, if not removed completely during roll grinding, become primarily respo-nsible for roll spalling. The high instances of roll spalling lead to increased specific roll consumption and production delays. The inspection of some 15-20% of CRM work rolls with portable Ultrasonic and Eddy Current flaw detectors was undertaken to detect and remove the service induced defects on surface & sub-surface regions of rolls which would otherwise have remained undetected leading to roll spalling and other associated failures. The incid-ences of spalling has reduced by up to 38% during the period of roll inspection compared to the spalling incid-ences in the prior periods of time leading to prolonged uses of rolls. Although no reduction in Specific Roll Consumption (SRC) has been observed, the loss of useful roll materials due to reduced incidences of spalling has reduced. The reduced occurences of roll spalling have also resulted in savings of premature roll changing time lead-ing to increased mill availibility

Fusion versus Breakup: Observation of Large Fusion Suppression for ^9Be + ^{208}Pb

Complete fusion excitation functions for $^{9}$Be + $^{208}$Pb have been measured to high precision at near barrier energies. The experimental fusion barrier distribution extracted from these data allows reliable prediction of the expected complete fusion cross-sections. However, the measured cross-sections are only 68% of those predicted. The large cross-sections observed for incomplete fusion products support the interpretation that this suppression of fusion is caused by $^{9}$Be breaking up into charged fragments before reaching the fusion barrier. Implications for the fusion of radioactive nuclei are discussed.Comment: RevTex, 11 pages, 2 postscript figures, to appear in PR

Distorted cyclotron line profile in Cep X-4 as observed by NuSTAR

We present spectral analysis of NuSTAR and Swift observations of Cep X-4 during its outburst in 2014. We observed the source once during the peak of the outburst and once during the decay, finding good agreement in the spectral shape between the observations. We describe the continuum using a powerlaw with a Fermi-Dirac cutoff at high energies. Cep X-4 has a very strong cyclotron resonant scattering feature (CRSF) around 30 keV. A simple absorption-like line with a Gaussian optical depth or a pseudo-Lorentzian profile both fail to describe the shape of the CRSF accurately, leaving significant deviations at the red side of the line. We characterize this asymmetry with a second absorption feature around 19 keV. The line energy of the CRSF, which is not influenced by the addition of this feature, shows a small but significant positive luminosity dependence. With luminosities between (1-6)e36 erg/s, Cep X-4 is below the theoretical limit where such a correlation is expected. This behavior is similar to Vela X-1 and we discuss parallels between the two systems.Comment: 6 pages, 4 figure, accepted for publication in ApJ letter

Modelling the spectral response of the Swift-XRT CCD camera: Experience learnt from in-flight calibration

(Abbreviated) We show that the XRT spectral response calibration was complicated by various energy offsets in photon counting (PC) and windowed timing (WT) modes related to the way the CCD is operated in orbit (variation in temperature during observations, contamination by optical light from the sunlit Earth and increase in charge transfer inefficiency). We describe how these effects can be corrected for in the ground processing software. We show that the low-energy response, the redistribution in spectra of absorbed sources, and the modelling of the line profile have been significantly improved since launch by introducing empirical corrections in our code when it was not possible to use a physical description. We note that the increase in CTI became noticeable in June 2006 (i.e. 14 months after launch), but the evidence of a more serious degradation in spectroscopic performance (line broadening and change in the low-energy response) due to large charge traps (i.e. faults in the Si crystal) became more significant after March 2007. We describe efforts to handle such changes in the spectral response. Finally, we show that the commanded increase in the substrate voltage from 0 to 6V on 2007 August 30 reduced the dark current, enabling the collection of useful science data at higher CCD temperature (up to -50C). We also briefly describe the plan to recalibrate the XRT response files at this new voltage.Comment: 27 pages, 29 figures (many in colour), accepted for publication in A&