A study of electric motors for use in liquid and gaseous helium Engineering report no. 3530

Electric motor design and operation in liquid and gaseous helium environment

Dynamics of Magnetized Bulk Viscous Strings in Brans-Dicke Gravity

We explore locally rotationally symmetric Bianchi I universe in Brans-Dicke gravity with self-interacting potential by using charged viscous cosmological string fluid. We use a relationship between the shear and expansion scalars and also take the power law for scalar field as well as self-interacting potential. It is found that the resulting universe model maintains its anisotropic nature at all times due to the proportionality relationship between expansion and shear scalars. The physical implications of this model are discussed by using different parameters and their graphs. We conclude that this model corresponds to an accelerated expanding universe for particular values of the parameters.Comment: 17 pages, 6 figure

Subnormal Vision in Uneventful Cataract Surgery after 6 Weeks – Hospital Based Study

Background: With accurate estimation of power of intraocular lens (IOL), uncomplicated cataract surgery and uneventful post operative period, the implant is capable of providing a visual acuity of 6/6 and a normal field of vision. However, post operative results are not always according to the expectations. This study is an attempt to find out causes of subnormal vision post uneventful cataract surgery with posterior chamber intraocular lens by various surgical techniques in Krishna Institute of Medical Sciences, Karad, Maharashtra, India. Aims and Objectives: To study the incidence of subnormal vision in patients who have undergone uneventful cataract surgery with posterior chamber IOL implant and relation between the type of surgery and IOL used and its effect on the subnormal vision post operatively, in Krishna Hospital. Material and Methods: 185 patients among 1230 who underwent uneventful cataract surgery were diagnosed to have sub-normal vision in our study, over the period of 18 months. All pseudophakic patients, who have undergone uneventful cataract surgery, with normal pre-operative assessment were included in the study. Diabetic and hypertensive patients without any maculopathy were also included. Patients with intra operative complications, traumatic cataract, complicated cataract and pre existing pathology were excluded. Result: Prevalence of sub-normal vision in our study was approximately 14.18%. Among all the causes of sub-normal vision, incidence of posterior capsular opacification (PCO) was maximum, (80.87%). Incidence of PCO was least in foldable IOLs as compared to square edge and non square edge

Generalised Separable Solution of Double Phase Flow through Homogeneous Porous Medium in Vertical Downward Direction Due to Difference in Viscosity

In this paper the instability (fingering) phenomenon in a double phase immiscible (oil and water) flow through the homogeneous porous medium with mean capillary pressure in the vertical downward direction is discussed. The mathematical formulation of this problem yields a nonlinear partial differential equation and the generalised separable solution is given in the exponential form. The numerical solution and graphical presentation is given using MAT LAB coding

From chaos to disorder: Statistics of the eigenfunctions of microwave cavities

We study the statistics of the experimental eigenfunctions of chaotic and disordered microwave billiards in terms of the moments of their spatial distributions, such as the Inverse Participation Ratio (IPR) and density-density auto-correlation. A path from chaos to disorder is described in terms of increasing IPR. In the chaotic, ballistic limit, the data correspond well with universal results from random matrix theory. Deviations from universal distributions are observed due to disorder induced localization, and for the weakly disordered case the data are well-described by including finite conductance and mean free path contributions in the framework of nonlinear sigma models of supersymetry.Comment: 5 pages + 2 JPG figure

Probability distribution of residence-times of grains in sandpile models

We show that the probability distribution of the residence-times of sand grains in sandpile models, in the scaling limit, can be expressed in terms of the survival probability of a single diffusing particle in a medium with absorbing boundaries and space-dependent jump rates. The scaling function for the probability distribution of residence times is non-universal, and depends on the probability distribution according to which grains are added at different sites. We determine this function exactly for the 1-dimensional sandpile when grains are added randomly only at the ends. For sandpiles with grains are added everywhere with equal probability, in any dimension and of arbitrary shape, we prove that, in the scaling limit, the probability that the residence time greater than t is exp(-t/M), where M is the average mass of the pile in the steady state. We also study finite-size corrections to this function.Comment: 8 pages, 5 figures, extra file delete

Bianchi Type I Magnetofluid Cosmological Models with Variable Cosmological Constant Revisited

The behaviour of magnetic field in anisotropic Bianchi type I cosmological model for bulk viscous distribution is investigated. The distribution consists of an electrically neutral viscous fluid with an infinite electrical conductivity. It is assumed that the component $\sigma^{1}_{1}$ of shear tensor $\sigma^{j}_{i}$ is proportional to expansion ($\theta$) and the coefficient of bulk viscosity is assumed to be a power function of mass density. Some physical and geometrical aspects of the models are also discussed in presence and also in absence of the magnetic field.Comment: 13 page

Correlations due to localization in quantum eigenfunctions of disordered microwave cavities

Non-universal correlations due to localization are observed in statistical properties of experimental eigenfunctions of quantum chaotic and disordered microwave cavities. Varying energy {E} and mean free path {l} enable us to experimentally tune from localized to delocalized states. Large level-to-level Inverse Participation Ratio (IPR I_{2}) fluctuations are observed for the disordered billiards, whose distribution is strongly asymmetric about . The density auto-correlations of eigenfunctions are shown to decay exponentially and the decay lengths are experimentally determined. All the results are quantitatively consistent with calculations based upon nonlinear sigma-models.Comment: 4 pages, LaTex, 5 .jpg figures. This paper with 5 embedded postscript figures available (PS,PDF) at http://sagar.physics.neu.edu/preprints

Fusion of 6^{6}Li with 159^{159}Tb} at near barrier energies

Complete and incomplete fusion cross sections for $^{6}$Li+$^{159}$Tb have been measured at energies around the Coulomb barrier by the $\gamma$-ray method. The measurements show that the complete fusion cross sections at above-barrier energies are suppressed by $\sim$34% compared to the coupled channels calculations. A comparison of the complete fusion cross sections at above-barrier energies with the existing data of $^{11,10}$B+$^{159}$Tb and $^{7}$Li+$^{159}$Tb shows that the extent of suppression is correlated with the $\alpha$-separation energies of the projectiles. It has been argued that the Dy isotopes produced in the reaction $^{6}$Li+$^{159}$Tb, at below-barrier energies are primarily due to the $d$-transfer to unbound states of $^{159}$Tb, while both transfer and incomplete fusion processes contribute at above-barrier energies.Comment: Phys. Rev. C (accepted

Participatory women’s groups and counseling through home visits to improve child growth in rural eastern India: protocol for a cluster randomised controlled trial

Background: Childhood stunting (low height-for-age) is a marker of chronic undernutrition and predicts children’s subsequent physical and cognitive development. An estimated 52 million children in India are stunted. There is a broad consensus on determinants of child undernutrition and interventions to address it, but a lack of operational research testing strategies to increase the coverage of these interventions in high burden areas. Our study aims to assess the impact, costeffectiveness, and scalability of a community intervention involving a government-proposed community-based worker to improve growth in children under two