Continuous-wave, multimilliwatt, mid-infrared source tunable across 6.4–7.5 μm based on orientation-patterned GaAs

We report a continuous-wave (cw) source of tunable mid-infrared radiation providing tens of milliwatt of output power in the 6460–7517 nm spectral range. The source is based on difference-frequency generation (DFG) in orientation-patterned (OP)-GaAs pumped by a Tm-fiber laser at 2010 nm and a 1064 nm-Yb-fiber-pumped cw optical parametric oscillator. Using a 25.7-mm-long OP-GaAs crystal, we have generated up to 51.1 mW of output power at 6790 nm, with >40 mW and >20 mW across 32% and 80% of the mid-infrared tuning range, respectively, which is to the best of our knowledge the highest tunable cw power generated in OP-GaAs in this spectral range. The DFG output at maximum power exhibits passive power stability better than 2.3% rms over more than 1 h and a frequency stability of 1.8 GHz over more than 1 min, in high spatial beam quality. The system and crystal performance at high pump powers have been studiedPostprint (published version

Wastewater treatment and reuse: an institutional analysis for Hyderabad, India

River basinsWater pollutionSewageEffluentsPollution controlLegislationWaste managementWater qualityGuidelinesWastewater irrigationHealth hazardsRiceGrassesInstitutional reformCase studies

TiO2- and BaTiO3-Assisted Photocatalytic Degradation of Selected Chloroorganic Compounds in Aqueous Medium: Correlation of Reactivity/Orientation Effects of Substituent Groups of the Pollutant Molecule on the Degradation Rate

Investigation of the photocatalytic activity of BaTiO3, a perovskite wideband gap semiconductor has been done in comparison with a widely used photocatalyst TiO2 for the degradation of 4-chlorophenol (4-CP), 4-chloroaniline (4-CA), 3,4-dichloronitrobenzene (3,4-DCNB), and 2,4,5-trichlorophenol (2,4,5-TCP). BaTiO3/TiO2 nanoparticles were prepared by gel-to-crystalline conversion method. BaTiO3 has exhibited better catalytic efficiency and process efficiency compared with TiO2 in most of the cases. The present research focuses mainly on two aspects: first the photocatalytic activity of BaTiO3, as there are very few reports in the literature, and second the reactivity/orientation effects of substituent groups of the pollutant molecules on the degradation rate. The above chloroorganic compounds have at least one chlorine substituent in common, along with other functional groups such as −OH, −NH2, and −NO2. Furthermore, the effect of electron acceptors and pH on the rate of degradation is presented. The reactions follow first-order kinetics. The degradation reaction was followed by UV−vis, IR, and GC-MS spectroscopic techniques. On the basis of the identification of the intermediates, a probable degradation reaction mechanism has been proposed for each compoun

Management of Diabetes Mellitus among Elderly Men and Women-Impact of Intervention Programme

The present research aimed at studying the effect of an educational module as an intervention programme in the management of Diabetes Mellitus among the elderly with regard to the improvement in their knowledge, attitude and practices. The sample constituted 80 elderly of whom 40 were men and 40 were women in the age group of 65 to 76 years. Structured Interview Schedule (SIS) developed by the investigators on knowledge, attitude and practices (KAP) with regard to diabetes was used for assessment. The module of educational programme was developed by the investigators for the benefit of diabetic people covering different aspects in the management of the disease. A repeated measure design was followed; accordingly, the sample were administered SIS to assess their initial KAP and they were provided intervention programme for a period of two months. Later, two months after the intervention, post assessment was conducted administering the same SIS. A comparison of pre and post test scores on KAP regarding diabetes was made. The statistical significance of mean difference in the scores was carried out using ‘t’ ratios. The findings revealed that both men and women respondents and the two age groups showed higher scores after intervention, on KAP regarding diabetes, than the pre intervention scores and individual differences in the score was also reduced considerably during post test