Natural activities of U, Th and K in some Indian building materials

The activity concentrations of ²²⁶Ra, ²³²Th and ⁴⁰K have been determined by gamma-ray spectrometry. The measured activity in the selected building materials ranges from (3.2 to 151.7 Bq/kg), 14 to 63.7 Bq/kg and 24.3 to 121.5 Bq/kg for ²²⁶Ra, ²³²Th and ⁴⁰K respectively. The activity concentration of ²³⁸U has been determined using fission track technique and the value ranges from 0.11 to 3.85 ppm. The concentrations for these natural radionuclides are compared with the reported data from other countries. Radium-equivalent activities (Ra_eq) are calculated for the measured samples to assess the radiation hazards arising due to the use of these materials in the construction of dwellings. All building materials have shown Ra_eq activities lower than the limit set in the Organization for Economic Cooperation and Development (OECD) report (370 Bq/kg), equivalent to external gamma dose of 1.5 mSvyr⁻¹. A good correlation has been observed between ²³⁸U and ²²⁶Ra in these materials.     

Effect of polycarboxylate type of super plasticizer on the hydration properties of composite cements

The work aims to study the effect of polycarboxylate type of super plasticizer on the hydration of composite cements. In this paper we have studied the hydration of 20 wt% fly ash (FA) blended Portland cement in the presence of 0.1 wt% super plasticizer (SP). Water consistency, setting times, non-evaporable water contents, compressive strength, water percolation, and air content measurements were carried out. In addition, X-ray diffraction studies were carried out to understand the hydration process. The results indicated the increase in compressive strength of the FA blended Portland cement in the presence of SP and with the increase of the hydration time.     

Radon exhalation potential and natural radioactivity in soil collected from the surrounding area of a thermal power plant

Journal of Radioanalytical and Nuclear Chemistry - In the present study, radon (222Rn), thoron (220Rn) exhalation rates, and the specific activities of 238U,232Th, and 40K of 75 soil samples...     

Asset portfolio optimization using support vector machines and real-coded genetic algorithm

This paper presents an integrated approach for portfolio selection in a multicriteria decision making framework. Firstly, we use Support Vector Machines for classifying financial assets in three pre-defined classes, based on their performance on some key financial criteria. Next, we employ Real-Coded Genetic Algorithm to solve a mathematical model of the multicriteria portfolio selection problem in the respective classes incorporating investor-preferences.     

Amperometric immunosensor for the detection of Vibrio cholerae O1 using disposable screen-printed electrodes.

A disposable amperometric immunosensor was studied for the rapid detection of Vibrio cholerae (V. cholerae), the causative agent of cholera, employing an indirect sandwich enzyme linked immunosorbent assay (ELISA) principle. Screen-printed electrodes (SPEs) were fabricated (by using commercial and homemade carbon inks), electrochemically characterized and the assay conditions were optimized for capturing antibodies and antigen. Whole cell lysate (WCL) of V. cholerae was used to raise antibodies in rabbits and mice. The antibodies raised against WCL of V. cholerae were found to be specific, and no cross reactivity was observed with other enteric bacteria. 1-Naphthyl phosphate was used as a substrate with the amperometric detection of its enzymatic hydrolysis product 1-naphthol at a potential of +400 mV vs. Ag/AgCl reference electrode. A comparison between the amperometric detection technique and the standard ELISA was made in terms of the total assay time, the amount of biological materials used and the sensitivity of detection. The minimum detection limit of the amperometric immunosensor for V. cholerae was found to be 10(5) cells/ml in 55 min, while ELISA detected 10(6) cells/ml in 4 h.     

Some group-invariant solutions of potential Kadomtsev–Petviashvili equation by using Lie symmetry approach

Nonlinear Dynamics - A variety of closed-form solutions such as multiple-front wave, kink wave, waves interaction, curve-shaped multisoliton, parabolic and stationary wave solutions have been...     

A Design Criteria to Achieve Giant Ising-Type Anisotropy in CoII-Encapsulated Metallofullerenes

Discovery of permanent magnetisation in molecules just like in hard magnets decades ago led to the proposal of utilising these molecules for information storage devices and also as Q-bits in quantum computing. A significant breakthrough with a blocking temperature as high as 80 K has been recently reported for lanthanocene complexes. While enhancing the blocking temperature further remains one of the primary challenges, obtaining molecules that are suitable for the fabrication of the devices sets the bar very high in this area. Encouraged by the fact that our earlier predictions of potential single-molecule magnets (SMMs) in lanthanide-containing endohedral fullerenes have been verified, here we set out to undertake a comprehensive study on Co^II-ion-encapsulated fullerene as potential SMMs. To study this class of molecules, we have utilised an array of theoretical methods ranging from density functional to ab initio CASSCF/NEVPT2 methods for obtaining reliable estimate of zero-field splitting parameters D and E. Additionally, we have also employed, for the first time a combination of molecular dynamics based on DFT methods coupled with CASSCF/NEVPT2 methods to seek the role of conformational isomers in the relaxation of magnetisation. Particularly, we have studied, Co@C₂₈, Co@C₃₈ and Co@C₄₈ cages and their isomers as potential target molecules that could yield substantial magnetic anisotropy. Our calculations categorically reveal a very large Ising anisotropy in this class of molecules, with Co@C₄₈ cages predicted to yield D values as high as −127 cm⁻¹. Our calculations on the smaller cages reveal the free movement of Co^II ion inside the cage, leading to the likely scenario of faster relaxation of magnetisation. However, larger fullerene cages were found to solve this issue. Further models with incorporating units such as {CoOZn}, {CoScZnN} inside larger fullerenes yield axial zero-field splitting values as high as −200 cm⁻¹ with negligible E/D values. As these units represent a strong axiality coupled with a viable way to obtain air-stable low-coordinate Co^II complexes, this opens up a new paradigm in the search of SMMs in this class of molecules.     

Radiological impact assessment of soil and groundwater of Himalayan regions in Uttarakhand,India

Journal of Radioanalytical and Nuclear Chemistry - In this study, we present the results of measurements and radiological impact of natural radioactivity in soil and groundwater of the Himalayan...     

Syntheses,structures and electrochemical properties of complexes of nickel(II) with triethylenetetramine and bidentate nitrogen donor co-ligands

Three new polyamine Ni(II) complexes, namely [Ni(trien)(phen)](BF₄)₂ 1, [Ni(trien)(bipy)](ClO₄)₂ 2 and [Ni(trien)(en)](ClO₄)₂ 3 [trine = triethylenetetramine, phen = 1,10-phenanthroline, bipy = 2,2′-bipyridyl, en = ethylenediamine] have been synthesized and characterized by physico-chemical and spectroscopic methods. Complexes 1 and 2 crystallize in monoclinic space group P21/c, and possess a distorted octahedral geometry. Significant hydrogen bonding interactions are found in both complexes.