Synthesis of mesoporous rebar MWCNT/alumina composite (RMAC) nodules for the effective removal of methylene blue and Cr (VI) from an aqueous medium.

The distinctive and tuneable physical, chemical and configurational properties of carbon nanotubes (CNTs), has prompted their combination with metal oxides to contrive carbon composites showing entrancing adsorption property with incredible potential in water treatment. MWCNT/Alumina (RMAC) nodules with effective adsorption capacity were synthesized following aqueous sol-gel route. Batch sorption experiments examined the efficiency of removal of dyes and heavy metal ions from an aqueous solution on RMAC nodules. The factors affecting adsorption were studied for adsorption of methylene blue dye (MB) and hexavalent chromium by altering the MWCNT concentration from 1 wt.% to 5 wt.%. The adsorption experiment demonstrated an adsorption capacity of 187.5 and 597 mg g-1 at 25 °C for MB and Cr (VI) respectively. Various characterization techniques such as XRD, BET, TEM, Raman, FTIR, TPD and CHN were employed to study the initial development of the material. Multiple adsorption interaction mechanisms (electrostatic interactions, hydrogen bonding, π-π electron-donor-acceptor interactions) may be credited for the remarkable adsorption capacity of these nodules. Results of this work are of great significance for environmental applications of Alumina/MWCNT composite as a promising adsorbent nanomaterial for organic pollutants from aqueous solutions. Apart from high sorption ability, these nodules offer ease of separation with splendid regeneration ability.

Coexistence of superconductivity and ferromagnetism in Sr0.5Ce0.5FBiS2-xSex (x = 0.5 and 1.0), a non-U material with Tc < TFM.

We have carried out detailed magnetic and transport studies of the new Sr0.5Ce0.5FBiS2-xSex (0.0 ≤ x ≤ 1.0) superconductors derived by doping Se in Sr0.5Ce0.5FBiS2. Se-doping produces several effects: it suppresses semiconducting-like behavior observed in the undoped Sr0.5Ce0.5FBiS2, the ferromagnetic ordering temperature, TFM, decreases considerably from 7.5 K (in Sr0.5Ce0.5FBiS2) to 3.5 K and the superconducting transition temperature, Tc, gets enhanced slightly to 2.9-3.3 K. Thus in these Se-doped materials, TFM is marginally higher than Tc. Magnetization studies provide evidence of bulk superconductivity in Sr0.5Ce0.5FBiS2-xSex at x ≥ 0.5 in contrast to the undoped Sr0.5Ce0.5FBiS2 (x = 0) where magnetization measurements indicate a small superconducting volume fraction. Quite remarkably, as compared with the effective paramagnetic Ce-moment (~2.2 µB), the ferromagnetically ordered Ce-moment in the superconducting state is rather small (~0.1 µB) suggesting itinerant ferromagnetism. To the best of our knowledge, Sr0.5Ce0.5FBiS2-x Sex (x = 0.5 and 1.0) are distinctive Ce-based bulk superconducting itinerant ferromagnetic materials with Tc < TFM. Furthermore, a novel feature of these materials is that they exhibit a dual and quite unusual hysteresis loop corresponding to both the ferromagnetism and the coexisting bulk superconductivity.

Participatory ergonomics in redesigning a dyeing tub for fabric dyers.

OBJECTIVE: The 'saree' worn by women in India and many South Asian countries is dyed using a tub, usually in small scale units employing low capital and a small number of workers. While using these tubs, workers adopt awkward postures over long periods of time which results in severe discomfort in the neck, shoulders and lower extremities. The purpose of the study was to redesign the dyeing tub using a participatory approach and to study the impact of the newly designed tub on the reported body discomfort and rate of production. METHODS: Redesigning of the dyeing tub was carried out using three parallel participative processes--(1) eliciting the views of workers who use the tub, (2) interacting with the proprietors of the small scale dyeing units (the employers) and the tub manufacturers, and (3) iterative prototype tub development based on inputs from the first two processes. These processes facilitated involvement of the stake-holders and the acceptance of change. The final prototype was tested by nine workers for a period of three months to evaluate the reduction in body discomfort and increase in rate of production (output). RESULTS: Studies on the impact of the new tub showed a reduction in discomfort level from 'severe' to 'moderate', and a mean increase of 7.9% in the output, confirming the benefits of the participative approach to ergonomics intervention. The involvement, trust and credibility generated by the participative process facilitated the acceptance of the final design.

Temperature-dependent Raman study of a CeFeAsO(0.9)F(0.1) superconductor: crystal field excitations, phonons and their coupling.

We report temperature-dependent Raman spectra of CeFeAsO(0.9)F(0.1) from 4 to 300 K in the spectral range of 60-1800 cm(-1) and interpret them using estimates of phonon frequencies obtained from first-principles density functional calculations. We find evidence for strong coupling between the phonons and crystal field excitations; in particular the Ce(3 + ) crystal field excitation at 432 cm(-1) couples strongly with the E(g) oxygen vibration at 389 cm(-1). Below the superconducting transition temperature, the phonon mode near 280 cm(-1) shows softening, signaling its coupling with the superconducting gap. The ratio of the superconducting gap to T(c), thus estimated to be ~10, suggests CeFeAsO(0.9)F(0.1) to be a strong coupling superconductor. In addition, two high frequency modes observed at 1342 and 1600 cm(-1) are attributed to electronic Raman scattering from the (x(2)-y(2)) to xz /yz d-orbitals of Fe.

TiO2-based nanotubes modified with nickel: synthesis, properties, and improved photocatalytic activity.

Titanate nanotubes containing 2.5 wt% Ni were synthesized from TiO2 sol using alkali hydrothermal treatment followed by a simple ion-exchange process. The changes in phase, shape and morphology, surface area, and photocatalytic activity of these nanotubes have been explored as a function of calcination temperature. The samples were characterized using standard techniques, including x-ray diffraction, transmission electron microscopy, scanning electron microscopy, inductively coupled plasma spectrometry, energy dispersive x-ray spectroscopy, and Brauner-Emmett-Teller surface area analysis. The study revealed that the titanate phase containing Ni ions can be converted to the anatase phase after certain heat treatments but, at the same time, the tubular morphology was partially lost. Investigation of photocatalytic properties demonstrated that the as-prepared Ni-titanate nanotubes were photocatalytically inactive, but when heated at temperatures below 500 degrees C their activity was significantly enhanced with the change in phase. The calcined nanotube samples carrying nickel ion showed better photocatalytic activity than calcined nanotube samples containing protons. The hydrogen adsorption capacity of these titanates has also been measured, and it was found that Ni-titanate nanotubes can adsorb more hydrogen than its counterpart Na-titanate.

Upper critical field, superconducting energy gaps and the Seebeck coefficient in La(0.8)Th(0.2)FeAsO.

We report the synthesis and characterization of a new electron-doped La-oxypnictide superconductor by partial substitution of lanthanum by thorium. The superconducting transition temperature at about 30.3 K was observed in La(0.8)Th(0.2)FeAsO, which is the highest in La-based oxypnictide superconductors synthesized at ambient pressure. We find that the decrease in lattice parameters with Th doping in LaOFeAs is more drastic as compared to that obtained by high pressure (6 GPa) synthesis of oxygen-deficient LaOFeAs. The resistivity and magnetic susceptibility measurements yield an upper critical field H(c2)(0) of 47 T. Partial substitution of Th in place of La induces electron doping, as shown by a negative Seebeck coefficient. The temperature-dependent magnetic penetration depth data provides strong evidence for a nodeless low energy gap of 1.4 meV.

Development of software for computer-assisted interpretation of pulmonary function tests.

This paper describes the need for the development of software for computer interpretation of Pulmonary Function Tests based on equations derived from Indian populations, and the development strategies adopted. The decision flowcharts are given. The present limitations and areas of ongoing refinement of the program are discussed.

A simplified method for the determination of blood lactic acid levels in occupational health practice.

Blood lactate assays are now widely used as measures of oxygen debt, especially in the areas of assessment of anaerobic power; assessment of fatigue; VO2(max) end-point determination, and rationalisation of work-rest cycles. A need exists for a method which will meet the following criteria: simplicity--single, small samples; rapidity, and feasibility with easily available instrument and chemicals. In order to develop such a method, the standard Barker and Summerson method was modified so as to use 0.02 ml of blood sample, and the following tests were carried out on 25 subjects at rest, and various levels of work: paired comparisons on analysis by macro and micro methods on the same sample of blood; paired comparisons on venous and capillary (fingertip) samples. In both cases, the paired values showed high correlation (0.99) and highly significant differences of means (P = 0.01 and 0.001, respectively). The regression equations obtained were also highly significant (P = 0.001). The combined equation was Y = 0.9655 X -0.4366; samples taken 2,4,5,6 and 10 mins after work showed that peak occurred in the 4th min sampling (2 vs 4 and 4 vs 6 min means significantly different at P = 0.05, and analysis of variance significant at (P = 0.001). It may be concluded that drawing, fingertip sample 4 mins after the end of work, analysing by the micro method, and using the regression equation will give the true peak blood lactate level, and satisfy the systems criteria defined.

Preliminary investigations into the loco-man factor on the Indian railways.

After a brief consideration of the existing literature pertaining to the ergonomic analysis and design of locomotive drivers' cabins, the present paper describes the results of a questionnaire survey among 26 electric locomotive drivers in India, with some recommendations. A preliminary analysis of the controls and displays in the cabin has been presented.

Ergonomics study of tea-leaf plucking operations: Criteria for selection and categorisation.

This paper describes a new method for the categorisation of female tea-leaf pluckers on the basis of quantity and quality of production, skill and efficiency. Subjects participating in a study on the ergonomics of tea-leaf plucking operations were so categorised, and the results have been compared with the existing groupings followed by the Tea-estate authorities. Such a method could facilitate predictive selection of pluckers, selection for training, and formation of groups in future studies.