Study of fiber optic sugar sensor

Over the last two decades, the fiber optic technology has passed through many analytical stages. Some commercially available fiber optic sensors, though in a small way, are being used for automation in mechanical and industrial environments. They are also used for instrumentation and controls. In the present work, an intensity-modulated intrinsic fiber optic sugar sensor is presented. This type of sensor, with slight modification, can be used for on-line determination of the concentration of sugar content in sugarcane juice in sugar industry. In the present set-up, a plastic fiber made of polymethylmethacrylate is used. A portion of the cladding (1 cm, 2 cm, 3 cm) at the mid-point along the length of the fiber is removed. This portion is immersed in sugar solution of known concentration and refractive index. At one end of the fiber an 850 nm source is used and at the other end a power meter is connected. By varying the concentration of sugar solution, the output power is noted. These studies are made due to the change in refractive index of the fluid. The device was found to be very sensitive which is free from EMI and shock hazards, stable and repeatable and they can be remotely interfaced with a computer to give on-line measurements and thus become useful for application in sugar industries.     

Corrigendum to the paper ``Adjoining an Order Unit to a Matrix Ordered Space'

An error has been detected (and also corrected) in Theorem 2.8 of the paper entitled “Adjoining an Order Unit to a Matrix Ordered Space” (Positivity, (2005)9: 207–223; DOI ). Accordingly, some of the results of the paper have been modified. Also, a notion of C*-matricially, Riesz normed spaces has been introduced.     

Environment-induced decoherence II. Effect of decoherence on Bell''s inequality for an EPR pair

According to Bell's theorem, the degree of correlation between spatially separated measurements on a quantum system is limited by certain inequalities if one assumes the condition of locality. Quantum mechanics predicts that this limit can be exceeded, making it nonlocal. We analyse the effect of an environment modelled by a fluctuating magnetic field on the quantum correlations in an EPR singlet as seen in the Bell inequality. We show that in an EPR setup, the system goes from the usual ‘violation’ of Bell's inequality to a ‘non-violation’ for times larger than a characteristic time scale which is related to the parameters of the fluctuating field. We also look at these inequalities as a function of the spatial separation between the EPR pair.     

Synthesis and spectral studies on nickel(II) complexes of amide group-containing ligands

Summary Complexes of nickel(II) with N-(2-carboxyphenyl)benzamide (CPBH), 2-amino-N-(2-carboxyphenyl)benzamide (ACPBH), N-isoxazolyl benzamide (IB), N-anilinobenzamide (AB), N-(2-pyridyl)-3-carboxypropanamide (PCPA) and N-(2-pyridyl)-2-carboxybenzamide (PCBA) have been isolated and characterized by elemental analyses, magnetic susceptibility measurements, thermal studies, i.r. and electronic spectral studies. The electrochemical behaviour of some complexes has also been investigated.     

Kinetics and mechanism of the oxidation of acetaldehyde by chromic acid in perchloric acid

Summary The oxidation of MeCHO by chromium(VI) has been studied in HClO₄ medium over a wide range of experimental conditions and has been found to obey the rate law;v=k[MeCHO][HCrO ₄ ^– ][H⁺]. The calculated H and-S values for the reaction are 30±2kJ mol^–1 and 171±7J mol^–1deg^–1, respectively. The mechanism is discussed in terms of carbon-hydrogen bond cleavage.     

Platinum carbonyl derived catalysts on inorganic and organic supports: a comparative study

Fumed silica, silica gel, silica-alumina and cross-linked (5.5%) polystyrene have been functionalized with quaternary ammonium groups and the Chini cluster [Pt₁₂(CO)₂₄]²⁻ has been anchored onto these functionalized materials by ion pairing. A catalyst has also been prepared by the adsorption of Na₂[Pt₁₂(CO)₂₄] on unfunctionalized fumed silica. The catalytic activities of the resultant materials, and that of commercially purchased 5% platinum on alumina have been studied for the hydrogenation of a variety of unsaturated compounds. The substrates studied are: α-acetamidocinnamic acid, cyclohexanone, acetophenone, methyl pyruvate, ethyl acetoacetate, nitrobenzene and benzonitrile. Compared to the polystyrene supported catalyst, the inorganic oxide supported catalysts have higher surface areas and for most of the substrates have notably higher activities. The functionalized fumed silica-based catalyst gives higher conversions than functionalized silica gel and silica-alumina-based catalysts. In the hydrogenation of acetophenone and ethyl acetoacetate, the functionalized fumed silica-based catalyst show superior activity compared to the commercial platinum catalyst, and the catalyst made by conventional adsorption method. In benzonitrile hydrogenation with all the cluster-derived catalysts a hydrazine derivative is selectively formed, but when the commercial platinum catalyst is used benzyl amine is the main product.