Cosmic prompt-muon spectrum at super high energies estimated from the JACEE primary spectrum using recent charmed-particle production cross-sections

Summary The prompt-muon flux generated directly from the decay of short-lived particles like D-mesons and Λ_c-hyperons produced during primary cosmic proton-air collisions has been estimated. The inclusive production cross-sections of charmed particles based on the recombination of quark parton model developed by Bugaevet al. and the primary-nucleon spectrum based on the latest JACEE balloon flight data have been used in this investigation. The derived direct muon spectrum has been compared with the earlier results of Elbertet al., Inazawaet al. Bugaevet al. and Allkofer and Bhattacharyya.     

Coordination Chemistry of N,N,N′,N′-Tetraethylpyridine-2,6-Dithiocarboxamide: Crystal and Molecular Structure of Chloro(N,N,N′,N′-Tetraethylpyridine-2,6-Dithiocarboxamide) Cobalt(II) Monocations and Di-μ-Chlorobis [Dichlorocobaltate(II)] Dianions, [{Co(DETP)Cl}+]2[Co2Cl4(μ 2-Cl2)]2−

Transition Metal Chemistry - The crystal and molecular structure of a 2:1 complex of CoCl2 with DETP (N,N,N′,N′-tetraethylpyridine-2,6-dithiocarboxamide), has been determined. The...     

Low-limit photo-acoustic detection of solid RDX and TNT explosives with carbon dioxide laser

We report the absorption spectra of RDX and TNT explosive samples in solid form at room temperature using a carbon dioxide laser-based photo-acoustic technique. A continuous wave ¹²C¹⁶O₂ laser, tunable between the 9.25–10.74 μm wavelength region, was used as an energy source. Interference-free limits of detection of solid RDX and TNT in simulated samples are estimated to be 10.0 and 16.5 ppbw, respectively. Published in Zhurnal Prikladnoi Spektroskopii, Vol. 73, No. 1, pp. 113–118, January–February, 2006.     

Multi-walled carbon nanotubes-ferroelectric liquid crystal nanocomposites: effect of cell thickness and dopant concentration on electro-optic and dielectric behaviour

Nanocomposites comprise functionalised multi-walled carbon nanotubes (0.00 wt%, 0.05 wt% and 0.07 wt%) and ferroelectric liquid crystals (FLCs) have been studied in the 5-μm- and 12-μm-thickness cells. Effect of anchoring energy and dopant concentration on the mesomorphic, electro-optic and dielectric behaviour of FLC has been explored. Fast switching time and increase in permittivity of non-doped FLCs and resulting nanocomposites as a function of increased cell thickness (from 5 to 12 μm) can be attributed to the change in the anchoring energy and direct current (DC) conductivity of the non-doped and doped systems. π–π stacking between carbon nanotubes and FLC layers give rise to the spontaneous polarisation of nanocomposites. Effect of cell thickness and anchoring energy on bistability are also discussed.     

Effect of addition of hydrophilic ionic liquid 3-methyl-1-pentylimidazolium tetrafluoroborate ([C5mim][BF4]) on an aqueous solution of triton X-100

The effect of addition of 3-methyl-1-pentylimidazolium tetrafluoroborate ([C₅mim][BF₄]) on the micellization of a nonionic surfactant, Triton X-100 (TX-100), has been investigated. The techniques employed to study the aggregation behavior are fluoremetry, dynamic light scattering (DLS), and transmission electron microscopy (TEM) and the concentration range covered is 0–2?wt% [C₅mim][BF₄]. The probes, viz. pyrene and pyrene-1-carboxaldehyde (PyCHO), have been used for fluorescence analysis. According to the findings, the addition of pentyl-chained ionic liquid (IL) to aqueous TX-100 results in a dramatic increase in critical micelle concentration (cmc) decrease in micellar size, and aggregation number pointing toward an overall “unfavorable” aggregation process.     

Bioactivity of some divalent M(II) complexes of penicillin based Schiff base ligand: Synthesis,spectroscopic characterization,and thermal study

A series of four novel metal complexes of Co(II), Ni(II), Cu(II) and Zn(II) were synthesized from Schiff base derived from amoxicillin (AMX) and picolinaldehyde (PC2). The ligand and metal complexes were fully characterized by physical and spectral techniques such as elemental microanalysis, conductivity, FT-IR, ¹H & ¹³C NMR, UV–vis, mass spectra, EPR, magnetic moment measurement, TGA/DTA, PXRD and antibacterial activity study. The spectroscopic study revealed 1:2 metal ligand ratio and coordination sites in the ligand for metal ions were evaluated by analysis of the spectral results. The surface morphology of the complexes was evaluated by SEM analysis. Molar conductivity implies non-electrolytic nature of the complexes. UV–vis. spectral study nicely supports octahedral geometry for Co(II) and Zn(II) complexes and tetrahedral geometry for Cu(II) complex. The kinetic parameters were extracted from Coats-Redfern equation. The PXRD study revealed nano-crystalline nature of Co(II), Ni(II) & Cu(II) complexes and amorphous nature of Zn(II) complex. The proposed geometry of the complexes was optimized by MM2 calculation supported in Cs-ChemOffice Ultra-11 program. The ligand and metal complexes were screened for antibacterial potency against four human pathogenic clinical strains of bacteria and the data revealed their promising antibacterial activity.     

Sustainability of bioplastics: Opportunities and challenges

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Bismuth nanowires for potential applications in nanoscale electronics technology.

Nanowires of bismuth with diameters ranging from 10 to 200 nm and lengths of 50 microm have been synthesized by a pressure injection method. Nanostructural and chemical compositional studies using environmental and high resolution transmission electron microscopy with electron stimulated energy dispersive X-ray spectroscopy have revealed essentially single crystal nanowires. The high resolution studies have shown that the nanowires contain amorphous Bi-oxide layers of a few nanometers on the surface. In situ environmental high resolution transmission electron microscopy (environmental-HRTEM) studies at the atomic level, in controlled hydrogen and other reducing gas environments at high temperatures demonstrate that gas reduction can be successfully applied to remove th oxide nanolayers and to maintain the dimensional and structural uniformity of the nanowires, which is key to attaining low electrical contact resistance.     

A general and efficient CuI/BtH catalyzed coupling of aryl halides with thiols

We report an exceptionally mild, general and efficient copper catalyzed cross coupling reaction of aryl bromides and thiols using 0.5 mol % CuI and 1 mol % benzotriazole. Experimental simplicity, generality, functional group tolerance and low cost of the catalyst are advantages of the protocol.     

Adsorption of traces of hafnium on manganese dioxide from acid solutions

Adsorption of hafnium on manganese dioxide from nitric and perchloric acid solutions has been studied and optimized with respect to shaking time, concentration of acid, oxide and metal. Maximum adsorption has been noticed from 0.1 mol · dm^–3 acid solutions in 20 minutes around 10^–5 mol · dm^–3 hafnium concentration. The adsorption of hafnium follows a Freundlich adsorption isotherm. Oxalate, thiosulfate, Na(I) and Al(III) from nitric acid and K(I) and Zn(II) from perchloric acid increase the adsorption, whereas all other anions and cations tested reduce the adsorption from both media Fe(III) and Sn(IV) significantly. Zn(II) and Co(II) show low adsorption affinity.