An Experimental and Numerical Study of Calliphora Wing Structure

Experiments are performed to determine the mass and stiffness variations along the wing of the blowfly Calliphora. The results are obtained for a pairs of wings of 10 male flies and fresh wings are used. The wing is divided into nine locations along the span and seven locations along the chord based on venation patterns. The length and mass of the sections is measured and the mass per unit length is calculated. The bending stiffness measurements are taken at three locations, basal (near root), medial and distal (near tip) of the fly wing. Torsional stiffness measurements are also made and the elastic axis of the wing is approximately located. The experimental data is then used for structural modeling of the wing as a stepped cantilever beam with nine spanwise sections of varying mass per unit lengths, flexural rigidity (EI) and torsional rigidity (GJ) values. Inertial values of nine sections are found to approximately vary according to an exponentially decreasing law over the nine sections from root to tip and it is used to calculate an approximate value of Young’s modulus of the wing biomaterial. Shear modulus is obtained assuming the wing biomaterial to be isotropic. Natural frequencies, both in bending and torsion, are obtained by solving the homogeneous part of the respective governing differential equations using the finite element method. The results provide a complete analysis of Calliphora wing structure and also provide guidelines for the biomimetic structural design of insect-scale flapping wings.     

Study of hyperfragments

1101 examples of non-mesic decay of hyperfragments, produced by high energy particles in nuclear emulsion stacks, have been used to obtain information on multinucleon interaction of Λ° hyperon in the decay of hyperfragments. From a study of events with two fast charged particles in decays of hyperfragments, the following two conclusions are drawn: (i) multinucleon interactions of Λ° in decay of hyperfragments is not significant; it occurs at the most in a few per cent of the cases, and (ii) there is strong evidence for the existence of final state interactions in decay of hyperfragments.     

Universality of the rate of growth of all hadron-nucleon total cross sections in the range 10 to 1500 GeV/c

The energy dependence of total cross section of hadron-nucleon collisions has been studied in terms of two components: the first component decreases with increasing energy of the incident hadron whereas the second component increases like ln s. The coefficient of ln s is found to be the same within 5% for p^±p, π^±p and K^±p collisions. The rate of growth of the rising component i.e., dσ /d(ln,s), of inelastic cross sections, deduced from σ_tot and σ_el, of pp and πp are found to be the same within 1.5 standard deviations; an attempt has been made to understand this near equality from factorization of the pomeron.     

Analysis of proton-carbon inelastic cross sections measured in satellite experiment and upper limit on primary cosmic ray deuteron flux in the energy range 20 to 600 GeV

An analysis has been made of the experimental results of Akimovet al on the inelastic cross sections of proton on proton and carbon targets in the energy range 20 to 600 GeV obtained from artificial earth satellites. It is found that an upper limit of 4% at 95% confidence level can be set on the fraction of deuterons relative to the flux of protons in the primary cosmic radiation at energies in the range 20 to 60 GeV. There is an indication for a rise of (29±7) mb in the inelastic cross section of proton against carbon in the energy range of 200 to 600 GeV over and above what is expected from Glauber’s theory. If this rise has to be interpreted as due to contamination from cosmic ray deuterons, the fraction of deuterons relative to protons needed is (15±4)% in this energy region.     

Studies on highly resistive ZnO thin films grown by DC-discharge-assisted pulsed laser deposition

It was found that by changing the substrate temperature from room temperature to ～850 °C, ZnO thin films with widely varying resistivity values could be grown on sapphire substrates using DC-discharge-assisted pulsed laser deposition (PLD) in oxygen ambient. The resistivity of the film grown at room temperature was too high to measure using our existing setup. However, as the growth temperature was increased from 550 °C to 750 °C, the resistivity first decreased slowly from ～14.0 to 4.4 Ω?m and then dropped suddenly to get saturated at ～2.0×10^?3 Ω?m as the growth temperature was further increased. In contrast to these, when there was no DC-discharge, the variation of resistivity for ZnO thin films grown by PLD was marginal up to the substrate temperature of ～850 °C. The reason for these observations was found to be the combined effects of reduction in donor defect densities like oxygen vacancies and zinc interstitials, introduction of acceptor type defects like interstitial oxygen and zinc vacancies, and the resultant poor carrier mobility at lower growth temperatures. At higher growth temperatures (800 °C and above), the appearance of oxygen vacancies and increase in mobility due to better crystalline quality were found to be responsible for reducing the resistivity. The PL of these films had significant emission in the green and red regions of the spectrum due to the aforesaid defect related transitions. Such highly resistive and luminescent films might be suited for applications such as resistive RAM, UV-photo detector, TFT, piezoelectric, transparent phosphor, and broadband LED applications.     

Effect of trapped ions on shielding of a charged spherical object in a plasma

Collisions have traditionally been neglected in calculating the shielding around a small spherical collector in a plasma, and the plasma flow to the collector. We show analytically that, in dusty plasmas under typical discharge conditions, ion charge-exchange collisions lead to the buildup of negative-energy trapped ions which dominate the shielding cloud in the nonlinear region near a dust grain and substantially increase the ion current to the grain, even when the mean-free path is much greater than the Debye length.     

Analysis of cosmic ray data on nucleon-nucleus collisions and its implication on high energy behaviour of nucleon-nucleon total cross section

From existing cosmic ray measurements of theinelastic collision cross sections of nucleons on nuclei of carbon, iron and lead in the range of energies 10² to 10⁴ GeV as well as the measurements of cross sections on air nuclei in the extensive air shower (EAS) regions (10⁵ to 10⁸ GeV), we conclude that the Glauber multiple scattering theory is adequate to account for the data. Recent suggestion of Maor and Nussinov to parametrize the nucleon-nucleon total cross section with a component growing proportional to ln² E (E is the incident energy) is at variance with the EAS data. However the data are consistent with a nucleon-nucleon total cross section rising no faster than lnE in these energy regions.     

Observation of a dip-bump structure in differential cross section for pp → nn in the 700–760 MeV/c momentum range

Based on a sample of about 3500 events, we have measured the total and differential cross sections of $\text{p}\text{p}\text{→}\text{n}\text{n}$ in the 700–760 MeV/c incident momentum region. It is found that σ_CE = 10.7 ± 0.2 mb at the average momentum of 730 MeV/c. The differential angular distribution is characterised by a sharp peak and a dip in the forward direction followed by a secondary maximum. The position of the dip corresponds to |t| ≈ m_π². These results are compared with the predictions of the model of Bryan-Phillips. On the other hand, this dip-bump structure can be well understood on a simple picture involving a π exchange and a constant background (for |t| ? 3 m_π²).     

Mössbauer studies of57Fe intercalated CdPS3

The results of Mössbauer Investigation of⁵⁷Fe, Intercalated in layered CdPS₃ of two differrent concentrations (0.05, 0.1) of iron point out that the guest species occupies three distinguishable sites in the Van der Waals gap and exhibits three doublets. Moreover, for the case of Fe_0.1 CdPS₃ in addition to these three doublets arising from Fe²⁺, three sets of magnetically split patterns Indicating ordering appear. The isomer shift, quadrupolar splitting, and Internal magnetic field for all the specimens studied, have been measured.     

Coordination compounds of Cu(II), Ni(II) and Co(II) with sulphamethazine-5-bromo-salicylaldimine

Coordination compounds of Cu (II), Ni (II) and Co (II) with sulphamethazine salicylaldimine (an antitubercular) have been prepared with a view to study their antibacterial activity. These complexes are granular, stable and are quantitatively formed and characterised by elemental analysis. Structures have been assigned based on their infrared, electronic absorption spectral and magnetic susceptibility studies. The antibacterial activity was tested against eleven available pathogens and in some cases complexes are found to be more potent.