A comparison of the structureborne and airborne paths for propfan interior noise

A comparison is made between the relative levels of aircraft interior noise related to structureborne and airborne paths for the same propeller source. A simple, but physically meaningful, model of the structure treats the fuselage interior as a rectangular cavity with five rigid walls. The sixth wall, the fuselage sidewall, is a stiffened panel. The wing is modeled as a simple beam carried into the fuselage by a large discrete stiffener representing the carry-through structure. The fuselage interior is represented by analytically-derived acoustic cavity modes and the entire structure is represented by structural modes derived from a finite element model. The noise source for structureborne noise is the unsteady lift generation on the wing due to the rotating trailing vortex system of the propeller. The airborne noise source is the acoustic field created by a propeller model consistent with the vortex representation. Comparisons are made on the basis of interior noise over a range of propeller rotational frequencies at a fixed thrust

A Pathwise Ergodic Theorem for Quantum Trajectories

If the time evolution of an open quantum system approaches equilibrium in the time mean, then on any single trajectory of any of its unravelings the time averaged state approaches the same equilibrium state with probability 1. In the case of multiple equilibrium states the quantum trajectory converges in the mean to a random choice from these states.Comment: 8 page

Effect of Ni-doping on magnetism and superconductivity in Eu0.5K0.5Fe2As2

The effect of Ni-doping on the magnetism and superconductivity in Eu0.5K0.5Fe2As2 has been studied through a systematic investigation of magnetic and superconducting properties of Eu0.5K0.5(Fe1-xNix)2As2 (x = 0, 0.03, 0.05, 0.08 and 0.12) compounds by means of dc and ac magnetic susceptibilities, electrical resistivity and specific heat measurements. Eu0.5K0.5Fe2As2 is known to exhibit superconductivity with superconducting transition temperature Tc as high as 33 K. The Ni-doping leads to a rapid decrease in Tc; Tc is reduced to 23 K with 3% Ni-doping, and 8% Ni-doping suppresses the superconductivity to below 1.8 K. In 3% Ni-doped sample Eu0.5K0.5(Fe0.97Ni0.03)2As2 superconductivity coexists with short range ordering of Eu2+ magnetic moments at Tm ~ 6 K. The suppression of superconductivity with Ni-doping is accompanied with the emergence of a long range antiferromagnetic ordering with TN = 8.5 K and 7 K for Eu0.5K0.5(Fe0.92Ni0.08)2As2 and Eu0.5K0.5(Fe0.88Ni0.12)2As2, respectively. The temperature and field dependent magnetic measurements for x = 0.08 and 0.12 samples reflect the possibility of a helical magnetic ordering of Eu2 moments. We suspect that the helimagnetism of Eu spins could be responsible for the destruction of superconductivity as has been observed in Co-doped EuFe2As2. The most striking feature seen in the resistivity data for x = 0.08 is the reappearance of the anomaly presumably due to spin density wave transition at around 60 K. This could be attributed to the compensation of holes (K-doping at Eu-site) by the electrons (Ni-doping at Fe site). The anomaly associated with spin density wave further shifts to 200 K for x = 0.12 for which the electron doping has almost compensated the holes in the system.Comment: 9 pages, 10 figure

Isozyme Studies on some Selected Camellia Clones

Polyphenoloxidase and peroxidase enzymes were extracted and the isozyme banding pattern was studied in twelve south Indian tea clones of Camellia species conserved an ex situ gene bank. Banding pattern exhibited variations at inter specific and clonal level. A maximum of 6 isozymes were observed for polyphenol oxidase in UPASI 2 clone and a minimum of 3 in the clone BSS 1. Peroxidase isozyme exhibited two bands in all the clones with variation in its mobility (Rf). Isozyme profile of polyphenol oxidase and peroxidise in few clones have shown unique pattern not detected in others. The isozyme profile of PPO indicates that the clones of the respective Camellia species are more similar than those of the other species. In the present study, isozyme banding pattern was compared among the Camellia species to understand the existing inter and intra clonal relationship

Ginzburg-Landau Like Theory for High Temperature Superconductivity in the Cuprates: Emergent d-wave Order

High temperature superconductivity in the cuprates remains one of the most widely investigated, constantly surprising, and poorly understood phenomena in physics. Here, we describe briefly a new phenomenological theory inspired by the celebrated description of superconductivity due to Ginzburg and Landau and believed to describe its essence. This posits a free energy functional for the superconductor in terms of a complex order parameter characterizing it. We propose, for superconducting cuprates, a similar functional of the complex, in plane, nearest neighbor spin singlet bond (or Cooper) pair amplitude psi_ij. A crucial part of it is a (short range) positive interaction between nearest neighbor bond pairs, of strength J'. Such an interaction leads to nonzero long wavelength phase stiffness or superconductive long range order, with the observed d-wave symmetry, below a temperature T_c\simzJ' where z is the number of nearest neighbours; it is thus an emergent, collective consequence. Using the functional, we calculate a large range of properties, e.g. the pseudogap transition temperature T* as a function of hole doping x, the transition curve T_c(x), the superfluid stiffness rho_s(x,T), the specific heat (without and with a magnetic field) due to the fluctuating pair degrees of freedom, and the zero temperature vortex structure. We find remarkable agreement with experiment. We also calculate the self energy of electrons hopping on the square cuprate lattice and coupled to electrons of nearly opposite momenta via inevitable long wavelength Cooper pair fluctuations formed of these electrons. The ensuing results for electron spectral density are successfully compared with recent ARPES experiments, and comprehensively explain strange features such as temperature dependent Fermi arcs above T_c and the 'bending' of the superconducting gap below T_c .Comment: 22 pages, 14 figures, to appear in Int J Mod Phys

Assessment of Genetic Relationship and Hybrid Evaluation Studies in Tea (Camellia sp.) by RAPD.

The genetic relationships among 12 tea accessions representing three species in the genus Camellia were studied using random amplified polymorphic DNA (RAPD) markers. The genetic distance matrix based on Euclidian Distances showed a minimum genetic distance of 2.24 between ‘UPASI-2’ and ‘UPASI-3’ clones and the maximum was 4.47 between ‘TRF-1’ and ‘TRI-2025’. The dendrogram based on Ward’s method of cluster analysis clearly characterized all 12 tea varieties into three clusters based on their types namely China, Assam and Cambod. Pair-wise genetic similarity index between parent and hybrid clones generated showed a highest mean of 0.59 between ‘TRI-2025’ and ‘BSS-1’ and a lowest of 0.34 between ‘UPASI-10’ and ‘BSS-1’. This study revealed that all the varieties analysed fall the present taxonomic framework of Camellia species and that the hybrid is of Cambod type. RAPD markers can thus be successfully applied in this taxon for the study of relationships and to confirm hybrid origin. The study offers a sound platform for future tea bre eding programmes in tea as well as evolution of hybrids in the commercially important tea varieties

Modeling and Analysis of Interactions in Virtual Enterprises

Advances in computer networking technology and open system standards are making the creation and management of virtual enterprises feasible. A virtual enterprise is a temporary consortium of autonomous, diverse, and possibly geographically dispersed organizations that pool their resources to meet short-term objectives and exploit fastchanging market trends. For a virtual enterprise to succeed, its business processes must be automated, and its startup costs must be minimized. In this paper we describe a formal framework for modeling and reasoning about interactions in a virtual enterprise. Such a framework will form the basis for tools that provide automated support for creation and operation of virtual enterprises. 1

Freezing transition of the vortex liquid in anisotropic superconductors

We study the solid-liquid transition of a model of pancake vortices in laminar superconductors using a density functional theory of freezing. The physical properties of the system along the melting line are discussed in detail. We show that there is a very good agreement with experimental data in the shape and position of the first order transition in the phase diagram and in the magnitude and temperature dependence of the magnetic induction jump at the transition. We analyze the validity of the Lindemann melting criterion and the Hansen-Verlet freezing criterion. Both criteria are shown to be good to predict the phase diagram in the region where a first order phase transition is experimentally observed.Comment: 9 pages, 10 figure

Distinct vortex-glass phases in Yb3_{3}Rh4_{4}Sn13_{13} at high and low magnetic fields

The vortex lattice (VL) in the mixed state of the stannide superconductor Yb$_{3}$Rh$_{4}$Sn$_{13}$ has been studied using small-angle neutron scattering (SANS). The field dependencies of the normalized longitudinal and transverse correlation lengths of the VL, $\xi_L/a_0$ and $\xi_T /a_0$, reveal two distinct anomalies that are associated with vortex-glass phases below $\mu_0H_l$~$\approx$~700~G and above $\mu_{0}H_h$~$\sim$~1.7~T ($a_0$ is the intervortex distance). At high fields, around 1.7~T, the longitudinal correlation decreases abruptly with increasing fields indicating a weakening (but not a complete destruction) of the VL due to a phase transition into a glassy phase, below $\mu_{0}H_{c_2}$(1.8 K)~$\approx$~2.5~T. $\xi_L/a_0$ and $\xi_T /a_0$, gradually decrease for decreasing fields of strengths less than 1~T and tend towards zero. The shear elastic modulus $c_{66}$ and the tilting elastic modulus $c_{44}$ vanish at a critical field $\mu_0H_l$~$\approx$~700~G, providing evidence for a disorder-induced transition into a vortex-glass. A 'ring' of scattered intensity is observed for fields lower than 700~G, $i.e.$, $\mu_{0}H_{c_1}$~=~135~G~$<$~$\mu_{0}H$~$<$~700~G. This low-field phenomenon is of different nature than the one observed at high fields, where $\xi_L/a_0$ but not $\xi_T/a_0$, decreases abruptly to an intermediate value