Mechanism of magnetostructural transformation in multifunctional Mn3_3GaC

Mn$_3$GaC undergoes a ferromagnetic to antiferromagnetic, volume discontinuous cubic-cubic phase transition as a function of temperature, pressure and magnetic field. Through a series of temperature dependent x-ray absorption fine structure spectroscopy experiments at the Mn K and Ga K edge, it is shown that the first order magnetic transformation in Mn$_3$GaC is entirely due to distortions in Mn sub-lattice and with a very little role for Mn-C interactions. The distortion in Mn sub-lattice results in long and short Mn-Mn bonds with the longer Mn-Mn bonds favoring ferromagnetic interactions and the shorter Mn-Mn bonds favoring antiferromagnetic interactions. At the first order transition, the shorter Mn-Mn bonds exhibit an abrupt decrease in their length resulting in an antiferromagnetic ground state and a strained lattice.Comment: Accepted in J. Appl. Phys. Please contact authors for supplementary informatio

An Imaging Polarimeter(IMPOL) for multi-wavelength observations

Taking advantage of the advances in array detector technology, an imaging polarimeter (IMPOL) has been constructed for measuring linear polarization in the wavelength band from 400-800 nm. It makes use of a Wollaston prism as the analyser to measure simultaneously the two orthogonal polarization components that define a Stoke's parameter. An achromatic half-wave plate is used to rotate the plane of polarization with respect to the axis of the analyser so that the second Stoke's parameter also can be determined. With a field of view correponding to about 30x30 sq. mm for a 1.2 m, f/13 telescope, a sensitive, liquid-nitrogen cooled CCD camera as the detector and a built-in acquisition and guidance unit, the instrument can be used for studying stellar fields or extended objects with an angular resolution close to 2 arcsec. The instrumental polarization is less than 0.05% and the accuracies of measurement are primarily limited by photon noise for typical observations.Comment: 10 pages including 5 embedded figures; submitted to Astronomy and Astrophysics Supplement Series; available on request to A. N. Ramaprakash ([email protected] or [email protected]); quote report n

Blast vibration monitoring in opencast mines

In this report the blast vibration monitoring techniques is studied. Ground vibration induced by blasting practices in mines has become a serious environmental issue in today’s scenario. Various factors influence the blast vibration being produced from the blasting practices such as the pattern of blasting, drilling pattern, quality and quantity of explosives being used, delay pattern etc. Also the vibration which is being generated by the blasting practices is comprised of two types of waves, body and surface waves. Some of the after blast features are also required to be studied in order to determine the safe blasting practices. Three types of adverse effects are generally associated with the blasting practices, Air blast, Fly rock and Ground vibration, However the amplitude, frequency and duration of the ground vibration is determined by the non-controllable(local geology, rock characteristic and distances of the structure from blast site) and controllable parameters(Charge weight, Delay interval, Type of explosive ,Direction of blast progression, Coupling, confinement, Spatial distribution of charges, Burden, spacing and specification and specific charge). For the purpose of determination of the safe Charge per Delay a number of researchers have given various theories and equations. The feasibility of the CMRI equation is studied in this report. Also there are various equipment’s available globally for measuring the ground vibration and air blast. In the present study Minimate Blaster specification has been studied in detail. All the blasting operations were obtained at different- different distances. According graphs were plotted for the data’s available from the blasting practices and the safe Charge per Delay and Peak Particle Velocity is determined for the mine in accordance with the DGMS regulations

Automated Classification of 2000 Bright IRAS Sources

An Artificial Neural Network (ANN) has been employed using a supervised back-propagation scheme to classify 2000 bright sources from the Calgary database of IRAS (Infrared Astronomy Satellite) spectra in the wavelength region of 8-23 microns. The data base has been classified into 17 pre-determined classes based on spectral morphology. We have been able to classify more than 80 percent of the 2000 sources correctly at the first instance. The speed and robustness of the scheme will allow us to classify the whole of LRS database, containing more than 50,000 sources in the future.Comment: 26 pages, To appear in ApJS after July 200

Contact-less characterizations of encapsulated graphene p-n junctions

Accessing intrinsic properties of a graphene device can be hindered by the influence of contact electrodes. Here, we capacitively couple graphene devices to superconducting resonant circuits and observe clear changes in the resonance- frequency and -widths originating from the internal charge dynamics of graphene. This allows us to extract the density of states and charge relaxation resistance in graphene p-n junctions without the need of electrical contacts. The presented characterizations pave a fast, sensitive and non-invasive measurement of graphene nanocircuits.Comment: 4 figures, supplementary information on reques

Performance of Mosambi Sweet Orange on Different Rootstocks Grown in Laterite Soil in West Bengal

A rootstock trial was laid out on sweet orange cultivar 'Mosambi' budded on five rootstocks viz., Jambhiri, Karna Khatta, Kichili, Rangpur lime and Sour orange. Tree growth was maximum on Jambhiri and minimum on Rangpur lime. Fruit yield (both in number and weight) was highest on Karna Khatta, rootstock followed by Rangpur lime while, fruit size and juice content were maximum on Rangpur lime. Total soluble solids and ascorbic acid content were highest in Karna Khatta, while T.S.S. to acid ratio was maximum in Rangpur lime. Foliar nitrogen content was highest in Karna Khatta followed by Rangpur lime. On the basis of four seasons data in respect of yield and fruit quality, Karna Khatta and Rangpur lime were the observed as suitable rootstocks for 'Mosambi' sweet orange grown on laterite soil of West Bengal

Health of Ammonia Horton Spheres and Foundations – A Case History

Liquid Ammonia is stored under pressure in steel Horton spheres (diameter 17 m) under operating pressures of 5-6 kg/cm2. These spheres are supported on twelve steel columns, concrete pedestals, concrete ring beam and raft or pile foundation depending on the soil conditions. The continuous circular ring beam rests on 72 concrete piles each 45 mm dia and 17 to 20 m long. The second identical Horton sphere is supported on a raft foundation. The two Horton spheres have been subjected to a hydrostatic loading of 1. 7 kg/cm2 and an additional pressure of 7.3 kg/cm2 for performance check. Strains were measured at the crowns, four equatorial points and in six columns. The test results indicate that the spheres and the columns behaved consistent with theoretical values. The concrete in foundations was found to be of good quality corresponding to M20 grade. The settlements under four columns of the fully loaded actual structure were within anticipated limits i.e. 4-6 mm

Comparative experimental and Density Functional Theory (DFT) study of the physical properties of MgB2 and AlB2

In present study, we report an inter-comparison of various physical and electronic properties of MgB2 and AlB2. Interestingly, the sign of S(T) is +ve for MgB2 the same is -ve for AlB2. This is consistent our band structure plots. We fitted the experimental specific heat of MgB2 to Debye Einstein model and estimated the value of Debye temperature (theta) and Sommerfeld constant (gamma) for electronic specific heat. Further, from gamma the electronic density of states (DOS) at Fermi level N(EF) is calculated. From the ratio of experimental N (EF) and the one being calculated from DFT, we obtained value of Lembda to be 1.84, thus placing MgB2 in the strong coupling BCS category. The electronic specific heat of MgB2 is also fitted below Tc using pi-model and found that it is a two gap superconductor. The calculated values of two gaps are in good agreement with earlier reports. Our results clearly demonstrate that the superconductivity of MgB2 is due to very large phonon contribution from its stretched lattice. The same two effects are obviously missing in AlB2 and hence it is not superconducting. DFT calculations demonstrated that for MgB2 the majority of states come from Sigma and Pi 2p states of boron on the other hand Sigma band at Fermi level for AlB2 is absent. This leads to a weak electron phonon coupling and also to hole deficiency as Pi bands are known to be of electron type and hence obviously the AlB2 is not superconducting. The DFT calculations are consistent with the measured physical properties of the studied borides, i.e., MgB2 and AlB2Comment: 16 pages Text + Figs: comments/suggestions welcome ([email protected])/www.freewebs.com/vpsawana

Hyperglycemia in transported neonates: A tertiary care experience

Introduction: Hyperglycemia is common in low birth weight and sick neonates which affect them adversely due to hyperosmolarity. As these neonates need often referral to higher setup, maintenance of euglycemia during transport should be emphasized. Objective: To know the prevalence of hyperglycemia on admission among outborn neonates and analyze the association of different transport variables and other clinical parameters with it. Methods: An observational, analytical, and cross-sectional study was designed and conducted on outborn neonates, enrolled by simple consecutive sampling from November 2014 to October 2016. All data were analyzed using SPSS version 24 and Microsoft Excel version 16 software. Results: Out of 394 outborn neonates, 33.75% were hyperglycemic. 76.4% newborns were transported by ambulance, 94.9% were stabilized before referral, 61.2% had accompanying paramedics, 86.5% neonates given intravenous fluid (IVF) during transport, 61.4% transported by moderately equipped, and 38.6% by poorly equipped vehicle. Admission hyperglycemia was significantly associated with variables such as gestational age, birth asphyxia, type of transport vehicle, duration of transport, IVF during transport, hypoxic ischemic encephalopathy, and neonatal jaundice with p<0.05. Logistic regression model taking variable which shows a strong association, we can predict 70.3% time correctly the hyperglycemia on admission. Conclusion: Prevalence of hyperglycemia found to be quite common in referred neonates. Although there is quite improvement in neonatal transport due to the implementation of various government transport schemes for patients, specialized neonatal transport service with accompanied skill personnel and care during transport is a long way to go