PRELIMINARY PHYSICO-CHEMICAL STUDY ON THE POLLUTION POTENTIAL OF RIVER LONGAI AT KARIMGANJ, ASSAM( INDIA)

In this study water quality of river Longai  in stretch of 5 km at Karimganj was investigated for pollution potential by determining various water quality parameter. A total number of fifteen water samples  were collected during the summer season. A uniform distance between the collection sites was maintained during the collection of  the samples. Analysis was done for the quantitative determination of the concentration of Fe, Mn, Cu, Cr, Cd and As and also for the qualitative determination of physical parameters like pH, EC,TSS,TDS,TS and total hardness of the collected water samples. The concentrations of Mn, Cr, Fe, Cd and As obtained were higher than the permissible limit declared by WHO. pH and electrical conductance of the water samples lies between 6.56 to 7.47  and 6.65 to 10.2 mscm-1 respectively. TSS, TDS,TS and total hardness were found to be within the permissible limit declared by WHO

Heterotrimetallic compounds containing Mo-M-Li [M = K, Rb and Cs] clusters : synthesis, structure, bonding, aromaticity and theoretical investigations of Li₂M₂ [M = K and Rb] and Cs₄ rings

A new polydentate fac-trioxo molybdenum complex, [MoO3L]3− {LH3 = nitrilotriacetic acid}, has been synthesized by the reaction of lithium molybdate with iminodiacetic acid. The trinegative complex anion coordinates the alkali metal cations, K+, Rb+ or Cs+. The potassium, rubidium and cesium complexes, [Li{K(H2O)2}MoO3L]n (1), [Li{Rb(H2O)2}MoO3L]n (2) and [Cs{Li(H2O)}2MoO3L]n (3), form heterotrimetallic coordination chains, containing planar rings of Li2M2 (M = K or Rb) and Cs4. Theoretical investigations on these rings were carried out using NICS calculations and ab initio ring current maps, revealing aromaticity to be of limited significance

Hydrogen bonded supramolecular architecture of a copper(II)-citrate coordination building block: Synthesis and crystal structure with theoretical insight

A tricarboxylate supported binuclear metal organic hybrids of Cu(II), [Cu2(µ-cit)(phen)4]·9H2O (1) has been synthesized using well known pyridyl based N,N′ linker, 1,10-phenanthroline and has been structurally characterized. The use of the flexible hydroxyl tricarboxylate, citrate, in designing such framework has created a marked diversity in the topology. The structural and topological diversity has been analyzed from the single crystal X-ray structure. Here, in an unit, each of the two Cu(II) centres are chelated by two phenanthrolineligands and citrate (cit4-) serves the role of a bridging ligand. Furthermore, the carboxylate moiety/hydroxyl oxygen sites of citrate and the aromatic chelating ligands promote the supramolecular recognition through hydrogen bonding and other non-covalent interactions (like π-π interaction) and thereby results in higher dimensional architecture.Along with this, there are water molecules as water of crystallization. The oxygen atoms of the carboxylate moiety involve in both inter and intra-molecular hydrogen bonding with the hydrogen atoms of the water molecules resulting in a hydrogen bonded helical supramolecular solid. Theoretical study is performed to analyze the structure and the role of non-covalent interactions through DFT based calculations and Hirshfeld surface analysis

Design of double toggle switching mechanisms

Toggle mechanisms are ubiquitous in electrical switches. However, literature for their mechanical design is scarce. This paper defines and classifies the toggle phenomena observed during switching. The concept of double toggle introduced in this paper enables a systematic screening of kinematic structure for the suitability in high performance switches. Seven structural and three kinematic criteria are identified for this purpose. It is also demonstrated that each such feasible kinematic structure lends itself to multiple physical embodiments. Therefore, the theory and procedure presented in this work can be used for design of numerous kinematically distinct mechanisms. One representative mechanical embodiment for a novel double toggle switch, including mass and geometric shape of links has been included in the paper. The switching behavior of the design is validated using Pro/Mechanism (TM). (C) 2013 Elsevier Ltd. All rights reserved

Parametric study of the behavior of double toggle switching mechanisms

The paper identified and characterized a special multi-degree of freedom toggle behavior, called double toggle, observed in a typical MCCB switching mechanism. For an idealized system, the condition of toggle sequence is derived geometrically. The existing tools available in a multi-body dynamics package are used for exploring the dynamic behavior of such systems parametrically. The double toggle mechanism is found to make the system insensitive to the operator's behavior; however, the system is vulnerable under extreme usage. The linkage kinematics and stopper locations are found to have dominant role on the behavior of the system. It is revealed that the operating time is immune to the inertial property of the input link and sensitive to that of the output link. Novel designs exploiting this observation, in terms of spring and toggle placements, to enhance switching performance have also been reported in the paper. Detailed study revealed that strategic placement of the spring helps in selective alteration of system performance. Thus, the study establishes the critical importance of the kinematic design of MCCB over the dynamic parameters. (C) 2013 Elsevier Ltd. All rights reserved

<span style="font-size:14.0pt;line-height: 115%;font-family:"Times New Roman";mso-fareast-font-family:"Times New Roman"; color:black;mso-ansi-language:EN-IN;mso-fareast-language:EN-IN;mso-bidi-language: HI" lang="EN-IN">Tetra-<i>n</i>-alkyl ammonium bromates as a primary oxidants in the oxidation of alcohols to carbonyl compounds</span>

1360-1362Tetra-n-alkyl ammonium bromates were prepared for the first time by a simple procedure from the corresponding bromides and used as primary oxidants for the oxidation of alcohols to carbonyl compounds. Reaction conditions are simple and products are obtained in high yields

Hydrogen bonded supramolecular architecture of a copper(II)-citrate coordination building block: Synthesis and crystal structure with theoretical insight

469-476A tricarboxylate supported binuclear metal organic hybrid of Cu(II), [Cu2(µ-cit)(phen)4]·9H2O (1) has been synthesized using the well known pyridyl based N,N′ linker, 1,10-phenanthroline and structurally characterized. The use of the flexible hydroxyl tricarboxylate citrate, in designing such a framework has created a marked diversity in the topology. The structural and topological diversity has been analyzed from the single crystal X-ray structure. Here, in a unit, each of the two Cu(II) centres is chelated by two phenanthroline ligands and citrate (cit4–) serves the role of a bridging ligand. Furthermore, the carboxylate moiety/hydroxyl oxygen sites of citrate and the aromatic chelating ligands promote supramolecular recognition through hydrogen bonding and other non-covalent interactions (like π-π interaction) and water of crystallization, thereby resulting in a higher dimensional architecture. The oxygen atoms of the carboxylate moiety involve in both inter and intra-molecular hydrogen bonding with the water molecules resulting in a hydrogen bonded helical supramolecular solid. Theoretical study is performed to analyze the structure and the role of non-covalent interactions through DFT based calculations and Hirshfeld surface analysis

Not Available

Not AvailableDefining nutrient management zones (MZs) is crucial for the implementation of sitespecific management. The determination of MZs is based on several factors, including crop, soil, climate, and terrain characteristics. This study aims to delineate MZs by means of geostatistical and fuzzy clustering algorithms considering remotely sensed and laboratory data and, subsequently, to compare the zone maps in the north-eastern Himalayan region of India. For this study, 896 grid-wise representative soil samples (0–25 cm depth) were collected from the study area (1615 km2). The soils were analysed for soil reaction (pH), soil organic carbon and available macro (N, P and K) and micronutrients (Fe, Mn, Zn and Cu). The predicted soil maps were developed using regression kriging, where 28 digital elevation model-derived terrain attributes and two vegetation derivatives were used as environmental covariates. The coefficient of determination (R2) and root mean square error were used to evaluate the model’s performance. The predicted soil parameters were accurate, and regression kriging identified the highest variability for the majority of the soil variables. Further, to define the management zones, the geographically weighted principal component analysis and possibilistic fuzzy c-means clustering method were employed, based on which the optimum clusters were identified by employing fuzzy performance index and normalized classification entropy. The management zones were constructed considering the total pixel points of 30 m spatial resolution (17, 86,985 data points). The area was divided into four distinct zones, which could be differently managed. MZ 1 covers the maximum (43.3%), followed by MZ 2 (29.4%), MZ 3 (27.0%) and MZ 4 (0.3%). The MZs map thus would not only serve as a guide for judicious location-specific nutrient management, but would also help the policymakers to bring sustainable changes in the north-eastern Himalayan region of India.Not Availabl