Spatial Variations of the Flood and Drought in the Northern Region of Sri Lanka

There are no any systematic orders in the occurrences of drought and flood hazards in Sri Lanka. Some areas have higher number of disaster occurrences and some other areas have lower numbers. In this situation this study focused the spatial variations of the drought and flood hazards in the Northern Region of Sri Lanka.  Main objective of this study is to identify the spatial patterns of drought and flood hazards in the study area. Monthly, Seasonal and annual climatic data for the stations Akkarayankulam, Ambalapperumalkulam, Iranaimadu, Kanukkerny, Karukkaikulam, Murunkan, Muththaiyankaddu, Nainathivu, Pallavarayankaddu, Pavatkulam, Thirunelveli, Vavunikkulam, and Vavuniya, were collected for the period from 1972 to 2012. Primary data for this study were collected using interviews and discussions and direct observations. Also varius sources of secondary data were used to carry out this study. Standardized Precipitation Index (SPI) has been used to identify the drought and flood hazards in every station for the period from 1972 to 2012. Krigging method of Arc GIS 9.2 version was used to identify the spatial variations of the drought and flood hazards.  During the South West Monsoon Season (SWMS) 03 severe drought in Vavunikkulam station and 09 in Akkarayankulam, 08 in Murungan, and 08 in Pavatkulam were identified. During the First Inter Monsoon Season (FIMS), extreme floods were experienced in several areas. Three in Iranaimadu, 03 in Thirunelveli, 03 in Pallavarayankaddu and 03 in Nainathivu station were identified in the Northern region using SPI method. During the Second Inter Monsoon Season (SIMS), 02 extreme floods in Thirunelveli, 02 in Vavuniya, and 03 in Murungan, and 02 in Akkarayankulam station and 07 severe droughts in Nainathivu and 05 in Vavuniya were also identified. During the North East Monsoon Season(NEMS), 03 extreme floods in Akkarayankulam, 03 in Ambalapperumalkulam and 03 severe floods, 03 extreme floods in Pallavaraykaddu, 03 severe floods in Muththaiyankaddu, 04 severe floods in Vavunikkulam station and 03 severe floods in Vavuniya were identified in the Northern region of Sri Lanka. Spatially some areas have been affected many times by flood and drought in the Northern Region of Sri Lanka. Comparatively, Eastern Parts of the study have more flood hazards and more number of droughts has occurred in the Western part of the study. Also 70% of the people expressed above thing. Also frequencies of the flood occurrences gradually decrease in the direction from the east to the west and similarly drought occurrences gradually decrease from the west to the east. Key Words: Drought, Flood, Seasons, Spatial Variations and Northern Regio

Upscaling of a reaction-diffusion-convection problem with exploding non-linear drift

We study a reaction-diffusion-convection problem with nonlinear drift posed in a domain with periodically arranged obstacles. The non-linearity in the drift is linked to the hydrodynamic limit of a totally asymmetric simple exclusion process (TASEP) governing a population of interacting particles crossing a domain with obstacle. Because of the imposed large drift scaling, this nonlinearity is expected to explode in the limit of a vanishing scaling parameter. As main working techniques, we employ two-scale formal homogenization asymptotics with drift to derive the corresponding upscaled model equations as well as the structure of the effective transport tensors. Finally, we use Schauder's fixed point theorem as well as monotonicity arguments to study the weak solvability of the upscaled model posed in an unbounded domain. This study wants to contribute with theoretical understanding needed when designing thin composite materials that are resistant to high velocity impacts.Comment: 27 pages, 3 figure

Understanding the solar-driven reduction of CO2 on doped ceria

With the appropriate materials, one can construct redox cycles that use CO2 as the oxidant, generating CO as the product. Here, we investigate thermochemical cycles using doped ceria compounds as the oxygen exchange medium. Doped samples are prepared using La, Cr, W, Zr, V, Y, and Ti as dopants. Studying the redox kinetics, we show that doping the pure ceria with zirconium strongly increases overall CO production, albeit at lower reaction rates. This is because the CO2 reduction step is second-order with respect to Ce(III). Doping the fluorite lattice with zirconium cations decreases the number of Ce(III) ions at the surface, and consequently slows down the reaction. This result is counter-intuitive, since normally you would think that the more reduction, the better. But the reactivity towards CO2 is actually determined by the surface Ce(III) ions, and so migration of dopant ions on the surface reduces its reactivity, even though the bulk Ce(III) concentration is higher. Our results demonstrate the importance of understanding surface kinetics when designing oxygen exchange materials for solar reactors.We thank the Dutch National Research School Combination Catalysis (NRSC-C) for funding

Ion transport regulation by P2Y receptors, protein kinase C and phosphatidylinositol 3-kinase within the semicircular canal duct epithelium

<p>Abstract</p> <p>Background</p> <p>The ionic composition of the luminal fluid in the vestibular labyrinth is maintained within tight limits by the many types of epithelial cells bounding the lumen. Regulatory mechanisms include systemic, paracrine and autocrine hormones along with their associated intracellular signal pathways. The epithelium lining the semicircular canal duct (SCCD) is a tissue that is known to absorb sodium and calcium and to secrete chloride.</p> <p>Findings</p> <p>Transport function was assessed by measurements of short circuit current (<it>I</it>_<it>sc</it>) and gene transcript expression was evaluated by microarray. Neither ATP nor UTP (100 microM) on the apical side of the epithelium had any effect on <it>I</it>_<it>sc</it>. By contrast, basolateral ATP transiently increased <it>I</it>_{<it>sc </it>}and transepithelial resistance dropped significantly after basolateral ATP and UTP. P2Y2 was the sole UTP-sensitive purinergic receptor expressed. <it>I</it>_{<it>sc </it>}was reduced by 42%, 50% and 63% after knockdown of α-ENaC, stimulation of PKC and inhibition of PI3-K, while the latter two increased the transepithelial resistance. PKCdelta, PKCgamma and PI3-K were found to be expressed.</p> <p>Conclusions</p> <p>These observations demonstrate that ion transport by the SCCD is regulated by P2Y2 purinergic receptors on the basolateral membrane that may respond to systemic or local agonists, such as ATP and/or UTP. The sodium absorption from endolymph mediated by ENaC in SCCD is regulated by signal pathways that include the kinases PKC and PI3-K. These three newly-identified regulatory components may prove to be valuable drug targets in the control of pathologic vestibular conditions involving dysfunction of transport homeostasis in the ear, such as Meniere's disease.</p

Chemical Recycling of Used PET by Glycolysis Using Niobia-Based Catalysts

Plastic production has steadily increased worldwide at a staggering pace. The polymer industry is, unfortunately, C-intensive, and accumulation of plastics in the environment has become a major issue. Plastic waste valorization into fresh monomers for production of virgin plastics can reduce both the consumption of fossil feedstocks and the environmental pollution, making the plastic economy more sustainable. Recently, the chemical recycling of plastics has been studied as an innovative solution to achieve a fully sustainable cycle. In this way, plastics are depolymerized to their monomers or/and oligomers appropriate for repolymerization, closing the loop. In this work, PET was depolymerized to its bis(2-hydroxyethyl) terephthalate (BHET) monomer via glycolysis, using ethylene glycol (EG) in the presence of niobia-based catalysts. Using a sulfated niobia catalyst treated at 573 K, we obtained 100% conversion of PET and 85% yield toward BHET at 195 °C in 220 min. This approach allows recycling of the PET at reasonable conditions using an inexpensive and nontoxic material as a catalyst

Titania-catalysed oxidative dehydrogenation of ethyl lactate: effective yet selective free-radical oxidation

We research here the catalytic oxidative dehydrogenation of ethyl lactate, as an alternative route to ethyl pyruvate. Testing various solid catalysts (Fe2O3, TiO2, V2O5/MgO–Al2O3, ZrO2, CeO2 and ZnO), we find that simple and inexpensive TiO2 efficiently catalyses this reaction under mild conditions. Furthermore, molecular oxygen was used as the terminal oxidant. Importantly, this reaction runs well also using inexpensive commercial solvent mixtures. Both the desired reaction and the by-products formation follow a free-radical mechanism. Remarkably, adding activated carbon, a solid radical scavenger, hardly affects the catalytic activity, but enhances the product selectivity. This is because this solid radical scavenger hampers the formation of undesired products in solution, without suppressing the oxidation at the catalyst surface

Silica-supported sulfonic acids as recyclable catalyst for esterification of levulinic acid with stoichiometric amounts of alcohols

Converting biomass into value-added chemicals holds the key to sustainable long-term carbon resource management. In this context, levulinic acid, which is easily obtained from cellulose, is valuable since it can be transformed into a variety of industrially relevant fine chemicals. Here we present a simple protocol for the selective esterification of levulinic acid using solid acid catalysts. Silica supported sulfonic acid catalysts operate under mild conditions and give good conversion and selectivity with stoichiometric amounts of alcohols. The sulfonic acid groups are tethered to the support using organic tethers. These tethers may help in preventing the deactivation of the active sites in the presence of water