Improved source of infrared radiation for spectroscopy

Radiation from a crimped V-groove in the electrically heated metallic element of a high-resolution infrared spectrometer is more intense than that from plane areas adjacent to the element. Radiation from the vee and the flat was compared by alternately focusing on the entrance slit of a spectrograph

Low radio frequency signatures of ram pressure stripping in Virgo spiral NGC 4254

We report the detection of extended low radio frequency continuum emission beyond the optical disk of the spiral galaxy NGC 4254 using the Giant Metrewave Radio Telescope. NGC 4254, which has an almost face-on orientation, is located in the outskirts of the Virgo cluster. Since such extended emission is uncommon in low inclination galaxies, we believe it is a signature of magnetised plasma pushed out of the disk by ram pressure of the intracluster medium as NGC 4254 falls into the Virgo cluster. The detailed spectral index distribution across NGC 4254 shows that the steepest spectrum alpha < -1 (S propto nu^{alpha}) arises in the gas beyond the optical disk. This lends support to the ram pressure scenario by indicating that the extended emission is not from the disk gas but from matter which has been stripped by ram pressure. The steeper spectrum of the extended emission is reminiscent of haloes in edge-on galaxies. The sharp fall in intensity and enhanced polarization in the south of the galaxy, in addition to enhanced star formation reported by others provide evidence towards the efficacy of ram pressure on this galaxy. HI 21cm observations show that the gas in the north lags in rotation and hence is likely the atomic gas which is carried along with the wind. NGC 4254 is a particularly strong radio emitter with a power of 7x10^{22} Watts/Hz at 240 MHz. We find that the integrated spectrum of the galaxy flattens at lower frequencies and is well explained by an injection spectrum with alpha_0=-0.45+-0.12. We end by comparing published simulation results with our data and conclude that ram pressure stripping is likely to be a significant contributor to evolution of galaxies residing in X-ray poor groups and cluster outskirts.Comment: 10 pages, 7 figures (figures 1,2 and 4 are in jpg format) and 2 tables; Accepted for publication in MNRA

A single molecule switch based on two Pd nanocrystals linked by a conjugated dithiol

Tunneling spectroscopy measurements have been carried out on a single molecule device formed by two Pd nanocrystals (dia, $\sim$5 nm) electronically coupled by a conducting molecule, dimercaptodiphenylacetylene. The I-V data, obtained by positioning the tip over a nanocrystal electrode, exhibit negative differential resistance (NDR) on a background M-I-M characteristics. The NDR feature occurs at $\sim$0.67 V at 300 K and shifts to a higher bias of 1.93 V at 90 K. When the tip is held in the middle region of the device, a coulomb blockade region is observed ($\pm\sim$0.3 V).Comment: Accepted in Praman

Effect of Several Auxiliary Ligands on the Extraction of Manganese(II) With 4-Benzoyl-3-methyl-1-phenyl-5-pyrazolone

The effect of 2-methyl pyridine N-oxide, 4-methyl pyridine N-oxide, pyridine N-oxide, 8-aminoquinoline, dibenzyl sulfoxide on the extraction of manganese(II) by 4-benzoyl-3-methyl-1-phe-\u27 nyl-5-pyrazolone (BMPP) in benzene from an aqueous buffered solution was studied. Synergistic enhancement was observed in all systems. Equilibrtum extraction constants and adduct formation constants were calculated. The results showed that synergistic extraction is due to the formation of adducts such as Mn(BMPP)2B where B represents the auxiliary ligand

Effect of β/α Strength Ratio on the Stress-Strain Curve of Beta Titanium Alloy by Finite Element Modelling

A systematic study was undertaken to determine the effect of the β/α strength ratio on the stress-strain behavior of near beta titanium alloy by the finite element method where the volume percent of the second phase was constant at 16 vol.%. The β/α strength ratio of the harder β phase to the softer α phase was varied from approximately 4 to 5 where the a phase strength (0.2% YS) was kept constant at 296 MPa. It was found that the flow stress did not vary linearly with the strength ratio. Stress gradients were found in both α and β phases and the nature of the stress gradient was found to depend on α particle shape. In some locations higher stresses were found in near the interface. In β, the stresses were generally higher near the interfaces