Top-down approach to fiber-top cantilevers

Taking inspiration from conventional top-down micromachining techniques, we have fabricated a low mass gold fiber-top cantilever via align-and-shine photolithography. The cantilever is characterized by measuring its resonance frequency and mechanical quality factor. Our results show that the device grants mass sensitivity comparable to that reported for similar standard cantilevers. This proof-of-concept paves the way to series production of highly sensitive fiber-top devices for remote detection of biochemical substances.     

A convenient formal synthesis of (2S,3S)-3-hydroxy pipecolic acid

A convenient synthesis of (2S,3S)-3-hydroxy pipecolic acid starting from inexpensive and easily available l-(+)-tartaric acid has been described.     

Yang–Mills on Quantum Heisenberg Manifolds

In the noncommutative geometry program of Connes, there are two variations of the concept of the Yang–Mills action functional. We show that for the quantum Heisenberg manifolds for generic parameter values they agree.     

Energy dispersive X-ray fluorescence determination of Fe in solid powder samples: A quality improvement perspective

The various factors affecting energy dispersive X-ray fluorescence determination of iron in solid powder samples were evaluated, to improve the quality of these measurements. Influence of samples/standards preparation and instrumental parameters such as applied voltage to the X-ray tube, tube output current, and duration of acquisition were assessed, and the optimized instrumental parameters were 12 kV, 200 μA, and 200 s, respectively. Linear dynamic range of the spectrometer was found to be 0.0052 to 5.042 g kg⁻¹. Detection limits of iron in various organic/inorganic samples were found to be 2.5 to 21.9 mg kg⁻¹. The values obtained during the present method were evaluated with neutron activation analysis.     

Hetero-aromatic N-base-promoted oxidation of 4-chlorobenzyl alcohol by Cr(VI) in micellar media

Research on Chemical Intermediates - A little attempt has been made to get in touch with the green chemistry studying the successful occurrence of oxidation of 4-chlorobenzyl alcohol to...     

Kinetic study of CO2 absorption in aqueous solutions of 2-((2-aminoethyl)amino)-ethanol using a stirred cell reaction calorimeter

In the literature, aqueous 2-((2-aminoethyl)amino) ethanol (AEEA) is identified as a promising solvent for postcombustion CO₂ capture. In this work, the kinetics of CO₂ absorption in the aqueous AEEA, containing a primary and a secondary amino group, is studied over a wide temperature range of 303.15-343.15 K and the amine concentration in the range of 0.47-2.89 M using the fall-in-pressure technique in a stirred cell reaction calorimeter setup with a horizontal gas-liquid interface. The overall rate constants for (AEEA + H₂O + CO₂) reaction system are estimated in the pseudo–first-order reaction regime. The kinetic models based on zwitterion and the termolecular reaction mechanisms are used to predict kinetic rate constants. The experimental kinetic data are better correlated using the zwitterion mechanism (AAD 9.18%) than that of the termolecular mechanism (AAD 10.4%). The density, viscosity, and physical solubility of pure components and aqueous binary mixtures of AEEA are also measured at the similar temperature and concentration ranges of rate kinetics. Empirical models are proposed to predict pure component density and viscosity data with AAD of 0.02% and 7.17%, respectively. The Redlich-Kister model, the Grunberg-Nissan model, and the O'Connell's model are used to correlate experimental density, viscosity, and physical solubility data of the binary mixtures with AAD of 0.034%, 4.92%, and 6.5%, respectively. The reaction activation energy (E_a ∼ 32 kJ/mol) of the (AEEA + H₂O + CO₂) system is calculated from the Arrhenius power-law model using the zwitterion mechanism, which indicates lower energy barrier than that of the reported value for monoethanolamine (∼44 kJ/mol) in the literature.     

Study of coulomb explosion and dissociation channels in dicationic argon clusters: a study based on stochastic optimization

In this article, we explore the use of stochastic optimization technique, namely simulated annealing, in elucidating the correct cut-off limit for suppression of Coulomb explosion in dicationic argon gas clusters. We also do a detail study of cluster sizes where the clusters are not stable as one single entity, and try to find out the dissociation channels for these, namely fission or non-fission type. We compare our results with available literature results, both theoretical and experimental.     

Green Synthesis of Pyrazole and Oxazole Derivatives

New intermediate 3‐methyl‐5‐oxopyrazol propanenitrile was synthesized by one pot three component reactions using ethyl cyanoacetate, hydrazine hydrate, and ethyl acetoacetate and was used for the synthesis of new oxazole and pyrazole derivatives. All reactions were carried out using eco‐friendly solvents and without catalyst.     

Water-soluble polymer anchored peroxotitanates as environmentally clean and recyclable catalysts for mild and selective oxidation of sulfides with H2O2 in water

Anchoring of peroxotitanium (pTi) species to linear water-soluble acrylic acid based polymers, poly(sodium acrylate) (PA) and poly(sodium methacrylate) (PMA) led to the successful synthesis of a pair of new, water-tolerant and recyclable catalysts of the type [Ti₂(O₂)₂O₂(OH)₂]^4-—L (L = PA or PMA), highly effective in chemoselective sulfoxidation of organic sulfides with 30% H₂O₂ in aqueous medium at ambient temperature. The catalytic protocol is high yielding (TOF up to 11,280 h^?1), operationally simple as well as environmentally clean and safe, being free from halide, or any other toxic auxiliaries. The catalysts are sufficiently stable to afford easy recyclability for at least 10 consecutive reaction cycles of sulfoxidation with consistent activity selectivity profile. Oxidation of dibenzothiophene (DBT) to respective high purity sulfoxide or sulfone could also be accomplished using the same catalysts by variation of reaction conditions.