Nonlinear bending-torsional vibration and stability of rotating, pretwisted, preconed blades including Coriolis effects

The coupled bending-bending-torsional equations of dynamic motion of rotating, linearly pretwisted blades are derived including large precone, second degree geometric nonlinearities and Coriolis effects. The equations are solved by the Galerkin method and a linear perturbation technique. Accuracy of the present method is verified by comparisons of predicted frequencies and steady state deflections with those from MSC/NASTRAN and from experiments. Parametric results are generated to establish where inclusion of only the second degree geometric nonlinearities is adequate. The nonlinear terms causing torsional divergence in thin blades are identified. The effects of Coriolis terms and several other structurally nonlinear terms are studied, and their relative importance is examined

On the unusual occurrence of penaeid eggs in the inshore waters of Madras

During one of the routine inshore plankton collections along the Madras coast, in the first week of February 1964, the tow net happened to sink down about 3 metres below the surface. The resulting haul consisted of an unprecedented number of penaeid eggs. On estimation a total of 3,00,000 eggs and 15,000 free nauplii were found to be present in that particular haul of 30 minutes duration. There appears to be no other report of such an abundance of penaeid eggs occurring in Indian waters, especially in the coastal waters of Madras. This phenomenal abundance of penaeid eggs is of considerable significance as regards the bionomics of Indian penaeid prawns. These eggs were transferred to fresh sea water and the progress of development was followed. The present brief report embodies the results obtained

Notes on the bionomics of the penaeid prawn Metapenaeus affinis (Milne edwards ) of the Malabar coast.

Metapenaeus affinis (M. Edw.) is one of the three species of Metapenaeus represented in the fishery on the Malabar coast. This species enjoys a wide distribution in the Indo- Pacific region, occurring all along the Indian coast, Tokyo to Formosa, in waters of Hawaiian Islands (Kubo, 1949) and along Southern Africa (Barnard, 1950). The bionomics of M. dobsoni and M. monoceros are known in some detail through the publications oi Menon (1951 &'55), Menon and Raman (1961) and George (1959 & '61). The available information on M. affinis is limited to a reference to its occurrence along the Travancore coast by Chopra (1943), an account of its fluctuations in abundance in Bombay waters by Shaikmahmud and Tembe (i960), a brief discussion of its sex ratio in Cochin waters and some observations on its fishery and feiology on Cochin and Alleppey coast by George (1961), The following account of the biology of the species is based on the observations made at Calicut during the years 1957 to 1959

Renewable Energy Systems: Development and Perspectives of a Hybrid Solar-Wind System

Considering the intermittent natural energy resources and the seasonal un-balance, a phtovoltaic-wind hybrid electrical power supply system was developed to accommodate remote locations where a conventional grid connection is inconvenient or expensive. However, the hybrid system can also be applied with grid connection and owners are allowed to sell excessive power back to the electric utility. The proposed set-up consists of a photo-voltaic solar-cell array, a mast mounted wind generator, lead-acid storage batteries, an inverter unit to convert DC to AC, electrical lighting loads, electrical heating loads, several fuse and junction boxes and associated wiring, and test instruments for measuring voltages, currents, power factors, and harmonic contamination data throughout the system. The proposed hybrid solar-wind power generating system can be extensively used to illustrate electrical concepts in hands-on laboratories and also for demonstrations in the Industrial Technology curriculum. This paper describes an analysis of local PV-wind hybrid systems for supplying electricity to a private house, farmhouse or small company with electrical power depending on the site needs. The major system components, work principle and specific working condition are presented

Effective chiral-spin Hamiltonian for odd-numbered coupled Heisenberg chains

An $L \times \infty$ system of odd number of coupled Heisenberg spin chains is studied using a degenerate perturbation theory, where $L$ is the number of coupled chains. An effective chain Hamiltonian is derived explicitly in terms of two spin half degrees of freedom of a closed chain of $L$ sites, valid in the regime the inter-chain coupling is stronger than the intra-chain coupling. The spin gap has been calculated numerically using the effective Hamiltonian for $L=3,5,7,9$ for a finite chain up to ten sites. It is suggested that the ground state of the effective Hamiltonian is correlated, by examining variational states for the effective chiral-spin chain Hamiltonian.Comment: 9 Pages, Latex, report ICTP-94-28

Hidden long range order in Heisenberg Kagome antiferromagnets

We give a physical picture of the low-energy sector of the spin 1/2 Heisenberg Kagome antiferromagnet (KAF). It is shown that Kagome lattice can be presented as a set of stars which are arranged in a triangular lattice and contain 12 spins. Each of these stars has two degenerate singlet ground states which can be considered in terms of pseudospin. As a result of interaction between stars we get Hamiltonian of the Ising ferromagnet in magnetic field. So in contrast to the common view there is a long range order in KAF consisting of definite singlet states of the stars.Comment: 4 pages, 3 figures, submitted to Physical Review Letter

Low-energy sector of the S=1/2 Kagome antiferromagnet

Starting from a modified version of the the S=1/2 Kagome antiferromagnet to emphasize the role of elementary triangles, an effective Hamiltonian involving spin and chirality variables is derived. A mean-field decoupling that retains the quantum nature of these variables is shown to yield a Hamiltonian that can be solved exactly, leading to the following predictions: i) The number of low lying singlet states increase with the number of sites N like 1.15 to the power N; ii) A singlet-triplet gap remains in the thermodynamic limit; iii) Spinons form boundstates with a small binding energy. By comparing these properties with those of the regular Kagome lattice as revealed by numerical experiments, we argue that this description captures the essential low energy physics of that model.Comment: 4 pages including 3 figure

2,4-dihydroxy benzaldehyde derived Schiff bases as small molecule Hsp90 inhibitors: rational identification of a new anticancer lead

Hsp90 is a molecular chaperone that heals diverse array of biomolecules ranging from multiple oncogenic proteins to the ones responsible for development of resistance to chemotherapeutic agents. Moreover they are over-expressed in cancer cells as a complex with co-chaperones and under-expressed in normal cells as a single free entity. Hence inhibitors of Hsp90 will be more effective and selective in destroying cancer cells with minimum chances of acquiring resistance to them. In continuation of our goal to rationally develop effective small molecule azomethines against Hsp90, we designed few more compounds belonging to the class of 2,4-dihydroxy benzaldehyde derived imines (1-13) with our validated docking protocol. The molecules exhibiting good docking score were synthesized and their structures were confirmed by IR, (1)H NMR and mass spectral analysis. Subsequently, they were evaluated for their potential to suppress Hsp90 ATPase activity by Malachite green assay. The antiproliferative effect of the molecules were examined on PC3 prostate cancer cell lines by adopting 3-(4,5-dimethythiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay methodology. Finally, schiff base 13 emerged as the lead molecule for future design and development of Hsp90 inhibitors as anticancer agents.Fil: Dutta Gupta, Sayan. Osmania University; India. Jawaharlal Nehru Technological University; IndiaFil: Revathi, B.. Osmania University; IndiaFil: Mazaira, Gisela Ileana. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Biológica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Galigniana, Mario Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Biológica; ArgentinaFil: Subrahmanyam, C. V. S.. Osmania University; IndiaFil: Gowrishankar, N. L.. Swami Vivekananda Institute of Pharmaceutical Sciences; IndiaFil: Raghavendra, N. M.. Osmania University; Indi

On the universality of the fluctuation-dissipation ratio in non-equilibrium critical dynamics

The two-time nonequilibrium correlation and response functions in 1D kinetic classical spin systems with non-conserved dynamics and quenched to their zero-temperature critical point are studied. The exact solution of the kinetic Ising model with Glauber dynamics for a wide class of initial states allows for an explicit test of the universality of the non-equilibrium limit fluctuation-dissipation ratio X_{\infty}. It is shown that the value of X_{\infty} depends on whether the initial state has finitely many domain walls or not and thus two distinct dynamic universality classes can be identified in this model. Generic 1D kinetic spin systems with non-conserved dynamics fall into the same universality classes as the kinetic Glauber-Ising model provided the dynamics is invariant under the C-symmetry of simultaneous spin and magnetic-field reversal. While C-symmetry is satisfied for magnetic systems, it need not be for lattice gases which may therefore display hitherto unexplored types of non-universal kinetics

Sequence Diversity Within the Three Agents of Groundnut Rosette Disease

Sequence diversity was examined in the coat protein (CP) gene of Groundnut rosette assistor virus (GRAV), the overlapping open reading frames (ORFs) 3 and 4 of Groundnut rosette virus (GRV), and the satellite RNA (sat-RNA) of GRV obtained from field isolates from Malawi and Nigeria. These three agents cause groundnut rosette disease, a major disease of groundnut in sub-Saharan Africa (SSA). Sequence analysis showed that the GRAV CP gene was highly conserved (97 to 99%) independent of its geographic source. The nucleotide sequence of the overlapping ORFs 3 and 4 of GRV was highly conserved (98 to 100%) from isolates within a geographic region but less conserved (88 to 89%) between isolates from the two distinct geographic regions. Phylogenetic analysis of the overlapping ORFs 3 and 4 show that the GRV isolates cluster according to the geographic region from which they were isolated, indicating that Malawian GRV isolates are distinct from Nigerian GRV isolates. Similarity within the sat-RNA sequences analyzed ranged from 88 to 99%. Phylogenetic analysis also showed clustering within the sat-RNA isolates according to country of origin, as well as within isolates from two distinct regions of Malawi. Because the GRAV CP sequence is highly conserved, independent of the geographic source of the GRAV isolates, the GRAV CP sequence represents the most likely candidate to use for pathogen-derived resistance in groundnut and may provide effective protection against groundnut rosette disease throughout SSA