In-Situ Measurement of Mechanical Properties using Automated Ball Indentation Technique

To assess the health/integrity of critical engineering component, evaluation of mechanical properties of the material from which the component is made is essential. Estimation of mechanical properties through conventional route is well established and standardized, but in-situ measurement on original structure or by using small amount of materials are in demand and yet to be standardized. As conventional mechanical test requires an adequate amount of test materials and in most of the cases this may not be available from the components that are in service. There-fore, an approach to find the mechanical properties either in-situ or using small amount of test materials got utter importance as an area of research for quite some time

Generation and characterization of carbonyl ylides from pyrazolinone spirooxiranes

Laser flash photolyses of 1-oxa-5,6-diazaspiro[2.4]hept-6-ene-4-ones I (Ar [triple bond] Ph, p-NO2Ph, p-CH3OPh; R1 [tripe bond] CH3, Ph; R2, R3 [triple bond] CH3; R2 [triple bond] Ph, p-NO2Ph, p-ClPh, 2-naphthyl; R3 [triple bond] H) and of the symmetrical oxirane II give rise to transients with absorption spectra in the visible region and lifetimes of the order of 0.3 - 10 [mu]s in benzene at room temperature. Sensitization experiments in some cases indicate that the intermediate may arise from a triplet as well as a singlet excited state. Transients from I are quenched by alcohols and 2,3-dimethyl-2-butene whereas that from II is not. Steady state photolyses of I in methanol give products consistent with the assignment of the structure of the transient as a carbonyl ylide incorporating the pyrazolinone ring.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/31041/1/0000718.pd

Avian Influenza Outbreaks in Chickens, Bangladesh

To determine the epidemiology of outbreaks of avian influenza A virus (subtypes H5N1, H9N2) in chickens in Bangladesh, we conducted surveys and examined virus isolates. The outbreak began in backyard chickens. Probable sources of infection included egg trays and vehicles from local live bird markets and larger live bird markets

Risk for Infection with Highly Pathogenic Avian Influenza Virus (H5N1) in Backyard Chickens, Bangladesh

Risk factors were feeding slaughter remnants of purchased chickens, having a body of water nearby, and contact with pigeons

Phototransformations of epoxyindanone adducts. Steady-state and laser flash photolysis studies

This article does not have an abstract

Triplet-state photophysics and transient photochemistry of cyclic enethiones. A laser flash photolysis study

The triplets of four cyclic enethiones, including thiocoumarin, have been investigated by nanosecond laser flash photolysis. Data are presented for transient spectra and kinetics associated with triplets, quantum yields of intersystem crossing and singlet oxygen photosensitization. The quenching of the thiocoumarin triplet (λ<SUP>T</SUP><SUB>max</SUB>= 485 nm, Iμ<SUP>T</SUP><SUB>max</SUB>= 8.8 × 10<SUP>3</SUP> dm<SUP>3</SUP> mol<SUP>−1</SUP> cm<SUP>−1</SUP> in benzene) by several olefins, amines and hydrogen donors occurs with rate constants of 10<SUP>7</SUP>-5 × 10<SUP>9</SUP> dm<SUP>3</SUP> mol<SUP>−1</SUP> s<SUP>−1</SUP>; the lower limits of quantum yields (⊕ PC) for the related photoreactions, estimated from ground-state depletion, are generally small (0.0-0.11 in benzene, except for good hydrogen donors, namely, p-methoxythiophenol and tri-n-butylstannane). The radical anion of thiocoumarin (λmax= 405-435 nm) is formed in two stages upon triplet quenching by triethylamine in acetonitrile; the fast component is the result of direct electron transfer to the triplet and the slower component is assigned to secondary photoreduction of the thione ground state by the α-aminoalkyl radical derived from the triethylamine radical-cation

Spectral properties of Eu3+ : ZnO-B2O3-SiO2 glasses

Studies on the vibronic spectral analysis of Eu3+ ions doped in zinc borosilicate glass have been performed in order to correlate them with the local environment of the dopant ion in this host matrix on the basis of the Fourier Transform infrared (FT-IR) spectroscopy. It is noticed that the Eu3+ ions are bonded to the bridging and non-bridging oxygens of BO3, BO4 and SiO4 Structural units. The Stark splittings exhibited especially by the emission transitions: D-0 -> F-7(1), D-5(0) -> F-7(2) and their intensity ratio (EMIR) could indicate that the Eu3+ ions are taking the sites, which lack inversion symmetry. Judd-Ofelt intensity (12, angstrom = 2, 4, 6) parameters have been obtained from the measured absorption spectra of Eu3+: Zinc borosilicate glass and these intensity defining factors are used in the computation of the emission transition probabilities, radiative rates, braching ratios and radiative lifetimes of the fluorescence transitions. Decay curves of the emission transitions ((5)Do -> F-7(0,1,2,3,4)) were measured and their lifetimes have been estimated. Besides this, Optical band gap energies (E-Opt) have also been evaluated from the base glass absorption spectrum and the values are found to be 4.82 and 4.60 eV for direct and indirect band gaps, respectively. (c) 2005 Elsevier B.V. All rights reserved

Steady-state and laser flash photolysis studies of 1-aziridinyl-1,2-dibenzoylalkenes

This article does not have an abstract

Photochemical transformations of 1-pyrazolyl-cis-1,2-dibenzoylalkenes. A laser flash photolysis investigation

This article does not have an abstract