Determination of the nature of the diperiodatocuprate(III) species in aqueous alkaline medium through a kinetic and mechanistic study on the oxidation of iodide ion

The nature of the diperiodatocuprate(III) (DPC) species present in aqueous alkaline medium has been investigated by a kinetic and mechanistic study on the oxidation of iodide by DPC. The reaction kinetics were studied over the 1.0 ´ 10)3±0.1 mol dm)3 alkali range. The reaction order with respect to DPC, as well as iodide, was found to be unity when [DPC] [I)]. In the 1.0 ´ 10)3±1.0 ´ 10)2 mol dm)3 alkali region, the rate decreased with increase in the alkali concentration and a plot of the pseudo-®rst order rate constant, k versus 1/[OH)] was linear. Above 5.0 ´ 10)2 mol dm)3, a plot of k versus [OH)] was also linear with a non-zero intercept. An increase in ionic strength of the reaction mixtures showed no e ect on k at low alkali concentrations, whereas at high concentrations an increase in ionic strength leads to an increase in k. A plot of 1/k versus [periodate] was linear with an intercept in both alkali ranges. Iodine was found to accelerate the reaction at the three di erent alkali concentrations employed. The observed results indicated the following equilibria for DPC.

Novel1, 3-Dipolar Cycloaddition Reactions of Acyclic Carbonyl Ylides and Related Chemistry

The thesis entitled novel 1,3-dipolar cycloaddition reactions of acyclic carbonyl ylides and related chemistry embodies the results of the investigations carried out to explore the reactivity of acyclic carbonyl ylides,generated by the reaction of dicarbomethoxy carbine and aldehydes towards dipolarophiles such as activated styrenes,1,2-and 1,4-quinones. In conclusion ,we have explored the reactivity pattern of acyclic carbonyl ylides derived from dicarbomethoxycarbene and aldehyde towards activated styrenes with a view to develop a stereoselective synthesis of highly substituted tetrahydrofuran derivatives. It was also found that the ylide could be trapped by various 1,2-and 1,4-diones to form dioxolane derivatives. It is noteworthy that the cycloaddition is highly region- and stereoselective. With isatins the ylide preferentially adds to the more electrone deficient carbonyl group making it regiospecific. Hetrocyclic compounds are of pivotal importance in organic chemistry, and enormous efforts have been devoted to develop new methodologies for their synthesis. It is noteworthy in this context that, 1,3-dipolar cycloaddition reaction,otherwise called Huisgen reaction, constitutes one of the most efficient methods for the synthesis of five membered heterocycles. Among the various dipoles, carbonyl ylides have received substiancial attention in recent years largely due to their utility in the synthesis of a wide range of oxygen hetrocycles, which are often found as structural subunits of many bioactive natural products.

Studies on the horizontal and vertical distribution of clouds and their impact on energetics of the Atmosphere over the Indian Region

Motivation for the present study is to improve the scienti c understanding on the prominent gap areas in the average three-dimensional distribution of clouds and their impact on the energetics of the earth-atmosphere system. This study is focused on the Indian subcontinent and the surrounding oceans bound within the latitude-longitude bands of 30 S to 30 N and 30 E to 110 E. Main objectives of this study are to : (i) estimate the monthly and seasonal mean vertical distributions of clouds and their spatial variations (which provide the monthly and seasonal mean 3-dimensional distributions of clouds) using multi-year satellite data and investigate their association with the general circulation of the atmosphere, (ii) investigate the characteristics of the `pool of inhibited cloudiness' that appear over the southwest Bay of Bengal during the Asian summer monsoon season (revealed by the 3-dimensional distribution of clouds) and identify the potential mechanisms for its genesis, (iii) investigate the role of SST and atmospheric thermo-dynamical parameters in regulating the vertical development and distribution of clouds, (iv) investigate the vertical distribution of tropical cirrus clouds and their descending nature using lidar observations at Thiruvananthapuram (8.5 N, 77 E), a tropical coastal station at the southwest Peninsular India, and (v) assessment of the impact of clouds on the energetics of the earth-atmosphere system, by estimating the regional seasonal mean cloud radiative forcing at top-of-the-atmosphere (TOA) and latent heating of the atmosphere by precipitating clouds using satellite data

Rainfall Climatology over Middle East Region and its Variability

A better understanding of the rainfall climatology of the Middle East region identifying the mechanisms responsible for the rain producing systems is essential for effective utilization of the water resources over the arid region. A comprehensive analysis on the rainfall climatology of the Middle East region is carried out to bring out the spatial and temporal variation of rainfall and mechanisms responsible for the rain events. The study was carried out utilizing rainfall, OLR, wind and humidity data sets procured from TRMM, NOAA and NCEP-NCAR. Climatology of annual rainfall brings out two areas of alarmingly low rainfall in the Middle East region: one in Egypt, Jordan and adjoining areas and the other in the southern part of Saudi Arabia. Daily rainfall analysis indicates that northern region gets rainfall mainly during winter and spring associated with the passage of Mediterranean low pressure systems whereas rain over the southern region is caused mainly by the monsoon organized convection, cross equatorial flow and remnants of low pressure systems associated with the monsoon during the summer season. Thermodynamic structure of the atmosphere reveals that the region does not have frequent local convection due to insufficient moisture content. The sinking motion associated with the sub tropic high pressure system and subsidence associated with the Walker circulation are responsible for maintaining warm and dry air over the region.

Depth wise variation of microbial load in the soils of midland region of Kerala: a function of important soil physicochemical characteristics and nutrients

Soil microorganisms play a main part in organic matter decomposition and are consequently necessary to soil ecosystem processes maintaining primary productivity of plants. In light of current concerns about the impact of cultivation and climate change on biodiversity and ecosystem performance, it is vital to expand a complete understanding of the microbial community ecology in our soils. In the present study we measured the depth wise profile of microbial load in relation with important soil physicochemical characteristics (soil temperature, soil pH, moisture content, organic carbon and available NPK) of the soil samples collected from Mahatma Gandhi University Campus, Kottayam (midland region of Kerala). Soil cores (30 cm deep) were taken and the cores were separated into three 10-cm depths to examine depth wise distribution. In the present study, bacterial load ranged from 141×105 to 271×105 CFU/g (10cm depth), from 80×105 to 131×105 CFU/g (20cm depth) and from 260×104 to 47×105 CFU/g (30cm depth). Fungal load varies from 124×103 to 27×104 CFU/g, from 61×103 to110×103 CFU/g and from 16×103 to 49×103 CFU/g at 10, 20 and 30 cm respectively. Actinomycetes count ranged from 129×103 to 60×104 CFU/g (10cm), from 70×103 to 31×104 CFU/g (20cm) and from 14×103 to 66×103 CFU/g (30cm). The study revealed that there was a significant difference in the depthwise distribution of microbial load and soil physico-chemical properties. Bacterial, fungal and actinomycetes load showed a decreasing trend with increasing depth at all the sites. Except pH all other physicochemical properties showed decreasing trend with increasing depth. The vertical profile of total microbial load was well matched with the depthwise profiles of soil nutrients and organic carbon that is microbial load was highest at the soil surface where organics and nutrients were highest

Diversity of Bacillus And Actinomycetes in the water and sediment samples from Kumarakom region of Vembanadu lake

Diversity of different groups of Bacillus and Actinomycetes in the water and sediment samples from kumarakom estuary was analysed to find out potential strains for further application. Bacillus genera was identified and grouped into five phenogroups .Phenogroups show differences in the shape of the spore,position of the spore,and swelling of the sporangium.Ability of the isolates to elaborate various hydrolytic enzymes and their ability to reduce nitrate and ferment various carbohydrate sources were also studied.

Raman and FTIR spectra of [Cu(H2O)6](BrO3)2 and [Al(H2O)6](BrO3)3 · 3H2O

Raman and FTIR spectra of [Cu(H2O)6](BrO3)2 and [Al(H2O)6](BrO3)3 · 3H2O are recorded and analyzed. The observed bands are assigned on the basis of BrO3 − and H2O vibrations. Additional bands obtained in the region of 3 and 1 modes in [Cu(H2O)6](BrO3)2 are due to the lifting of degeneracy of 3 modes, since the BrO3 − ion occupies a site of lower symmetry. The appearance 1 mode of BrO3 − anion at a lower wavenumber (771 cm−1) is attributed to the attachment of hydrogen to the BrO3 − anion. The presence of three inequivalent bromate groups in the [Al(H2O)6](BrO3)3 · 3H2O structure is confirmed. The lifting of degeneracy of 4 mode indicates that the symmetry of BrO3 − anion is lowered in the above crystal from C3v to C1. The appearance of additional bands in the stretching and bonding mode regions of water indicates the presence of hydrogen bonds of different strengths in both the crystals. Temperature dependent Raman spectra of single crystal [Cu(H2O)6](BrO3)2 are recorded in the range 77–523 K for various temperatures. A small structural rearrangement takes place in BrO3 − ion in the crystal at 391 K. Hydrogen bounds in the crystal are rearranging themselves leading to the loss of one water molecule at 485 K. This is preceded by the reorientation of BrO3 − ions causing a phase transition at 447 K. Changes in intensities and wavenumbers of the bands and the narrowing down of the bands at 77 K are attributed to the settling down of protons into ordered positions in the crystal

Geochemistry of core sediment from antarctic region

Southern Ocean (SO) is the fourth largest Ocean comprising the southern portions of the Atlantic Ocean, Indian Ocean and Pacific Ocean. Sediment core sample (660 34’S and 580 40’E)was collected onboard O.R.V Sagar Nidhi from January to March 2010 in the Fourth Southern Ocean expedition cruise launched by the National Centre for Antarctic and Ocean Research, Goa . Sedimentary records from this area reveal the sensitivity and climatic variability’s of the region over a large time scale. Organic matter (OM) and textural behaviour of the samples were analyzed and processed concurrently. Distribution of OM, Total Organic Carbon (TOC), Protein, Lipid and Carbohydrate along with the trace metal was highlighted. Textural variation was in the array of Sand >Clay >Silt. Sand content ranges from 30.29% to 80.11%. The order of relative distribution of OM was Lipid >Protein > TOC > Carbohydrate. The average concentrations of TOC, Protein, Lipid and Carbohydrate were 2.2 mg/g, 1.2 mg/g, 3.3 mg/g and 1.1mg/g respectively. Protein to carbohydrate ratio and lipid to carbohydrate ratio were also encountered to understand the respective freshness and nutritional quality of the sediments. Trace metal distribution showed the average concentration was maximum for Mn and minimum for Co.