2,471 research outputs found

    Physical and geotechnical characterization of water treatment plant residuals

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    The study of Water Treatment Plant (WTP) residuals is of recent origin and very little information is available in literature regarding these residuals. These waste materials have high solids contents, even in the mechanically dewatered condition, making it difficult to handle. These, along with stringent environmental regulations have forced the water utilities to look for new disposal options for these residuals. For this purpose as well as for evaluating suitable options for the beneficial reuse of residuals, it is essential to characterize WTP residuals. As the dewatered residuals are plastic, the researcher may be prompted to treat these materials as clays. But, unlike clays, these residuals lose all their plasticity and behave like granular materials upon drying and weathering. Furthermore, available literature indicates that the compaction characteristics for these materials are different depending upon whether the test is carried out from the \u27wet to dry condition or from dry to wet condition. Therefore, WTP residuals are different from clays, due to the presence of organics, and high concentrations of chemicals. It is postulated that the above changes in behavior of residuals are brought about by the change in structure, resulting in increased cementation and increase in grain size. This reinforces the need for characterizing these materials. In this research, geotechnical tests were performed on six residual samples and geoenvironmental tests were carried out three on residuals to determine the causes and mechanisms responsible for the changes in behavior of residuals. Grain size analysis conducted by sieve, hydrometer analyses and particle size analyzer indicated that particle sizes increased substantially upon weathering and drying. Electron micrographs, elemental maps, X-Ray diffraction and X-Ray Fluorescence spectra were obtained. The results indicated that the particle size increase could be attributed to aggregation due to organic matter and cementation due to metal oxides such as calcium oxide. It was also observed that no leaching of metals occurred due to drying, freeze, and thaw effects

    Effect of Hedging-Integrated Rule Curves on the Performance of the Pong Reservoir (India) During Scenario-Neutral Climate Change Perturbations

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    This study has evaluated the effects of improved, hedging-integrated reservoir rule curves on the current and climate-change-perturbed future performances of the Pong reservoir, India. The Pong reservoir was formed by impounding the snow- and glacial-dominated Beas River in Himachal Pradesh. Simulated historic and climate-change runoff series by the HYSIM rainfall-runoff model formed the basis of the analysis. The climate perturbations used delta changes in temperature (from 0° to +2 °C) and rainfall (from −10 to +10 % of annual rainfall). Reservoir simulations were then carried out, forced with the simulated runoff scenarios, guided by rule curves derived by a coupled sequent peak algorithm and genetic algorithms optimiser. Reservoir performance was summarised in terms of reliability, resilience, vulnerability and sustainability. The results show that the historic vulnerability reduced from 61 % (no hedging) to 20 % (with hedging), i.e., better than the 25 % vulnerability often assumed tolerable for most water consumers. Climate change perturbations in the rainfall produced the expected outcomes for the runoff, with higher rainfall resulting in more runoff inflow and vice-versa. Reduced runoff caused the vulnerability to worsen to 66 % without hedging; this was improved to 26 % with hedging. The fact that improved operational practices involving hedging can effectively eliminate the impacts of water shortage caused by climate change is a significant outcome of this study

    Facilities and services of the career information centres of public libraries in Karnataka: A study

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    The paper focuses on the various information services being offered by the competitive examination and career information centres of the public libraries in Karnataka. Altogether, there are 27 competitive examination and career information centres attached to the city central libraries in Karnataka which are catering to the information needs of youths who appear for competitive examinations and also seek job opportunities. The study has also covered aspects pertaining to the library infrastructure facilities being extended to the users of the centres. The responses pertaining to the facilities and services have been elucidated from the chief librarians of the public libraries through the questionnaire method

    Lichens: a novel and potential source as antimicrobials for human use

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    The use of lichens in medicine is based on the fact that they contain unique and varied biologically active substances, as antimicrobials.  Since they are natural antibiotics, their metabolites exert a wide variety of biological actions including antimycotic, antiviral, anti-inflammatory, analgesic, antipyretic, antiproliferative, and cytotoxic effects, they are considered as potential drugs. They contain a variety of secondary metabolites with strong antioxidant activity. These are substances which have high ability to scavenge toxic free radicals due their phenolic groups. These manifold activities of lichen metabolites have now been recognized, and therefore their therapeutic potential have great impact in pharma industries. The present article discusses the importance of lichens in inhibiting various types of human pathogens in addition to their chemical composition and pharmacological activities

    A convenient chromatography-free access to enantiopure 6,6'-di-tert-butyl-1,1'-binaphthalene-2,2'-diol and its 3,3'-dibromo, di-tert-butyl and phosphorus derivatives: utility in asymmetric synthesis

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    A simple chromatography-free high-yielding synthesis of the hexane-soluble enantiopure 6,6'-di-tert-butyl-1,1'-binaphthalene-2,2'-diol 3 (6,6'-di-tert-butyl BINOL) using Friedel-Crafts reaction on 1,1'-binaphthalene-2,2'-diol 1 (BINOL) is described. The enantiomeric purity was fully maintained in the reaction. Compound 3 has been used as an entry point for the convenient chromatography-free synthesis of 3,3',6,6'-tetra-tert-butyl BINOL 4 and 3,3'-dibromo-6,6'-di-tert-butyl BINOL 5. A straightforward route to enantiopure bisphosphites [(6,6'-R2C20H10O2)P]2[O2C20H10-6,6'-R2] [R = H 15, t-Bu 16] by simply reacting phosphorochloridite (6,6'-R2C20H10O2)PCl [R = H20, t-Bu 6] with metallic sodium is highlighted. The identity of 15 and 16 as their selenium-oxidized products 17 and 18 (at phosphorus center) is confirmed by X-ray crystallography (17 in the enantiopure form and 18 as racemate). Various enantiopure phosphoramidites of the modified BINOL have been synthesized. It is established that even when the phosphoramidites derived from the unsusbstituted BINOL 1 fail to give an appreciable optical induction in the asymmetric reduction of acetophenone/phenacyl chloride, those derived from 3 do induce moderate chiral induction (up to 30% ee in the case for acetophenone and 43% ee in the case of phenacyl chloride), thus leaving scope for further improvement in ee for related reactions

    A multicomponent model of the infrared emission from Comet Halley

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    A model based on a mixture of coated silicates and amorphous carbon grains produces a good spectral match to the available Halley data and is consistent with the compositional and morphological information derived from interplanetary dust particle studies and Halley flyby data. The dark appearance of comets may be due to carbonaceous coatings on the dominant (by mass) silicates. The lack of a 10 micrometer feature may be due to the presence of large silicate grains. The optical properties of pure materials apparently are not representative of cometary materials. The determination of the optical properties of additional silicates and carbonaceous materials would clearly be of use

    Ferrocenyl substituted chlorostilbenes and butadienes

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    The readily accessible α-chlorophosphonates (OCH2CMe2CH2O)P(O)CH(Cl)---C6H4-4-R [1: R=Me (a), OMe (b), Cl (c), H (d)] react with ferrocenecarboxaldehyde in the presence of NaH [Horner-Wadsworth-Emmons reaction] to give good yields of ferrocenyl substituted chlorostilbenes. The novel bis ferrocenyl butadiene C5H5FeC5H4---CH=CH---C(CN)CHC5H4FeC5H5 (9) as well as the ferrocenyl 2-cyano-1,3-butadienes 4-R---C6H4---CH=CH---C(CN)=CHC5H4FeC5H5 [R=Me (10a), OMe (10b), Cl (10c)] have been obtained by using the new allylphosphonate (OCH2CMe2CH2O)P(O)CH2C(CN)=CHC5H4FeC5H5 (8); the latter compound was prepared in good yields by the reaction of the Baylis-Hillman adduct, C5H5FeC5H4CH(OH)C(CN)=CH2 (7), with the chlorophosphite (OCH2CMe2CH2O)PCl. The electrochemical behavior of the ferrocenyl compounds thus synthesized has been studied; two reversible one-electron processes are observed in the case of compound 9 suggesting a cooperative interaction between the two ferrocenyl residues

    Utilizing the protected learning calculation method to forestall the Black Hole Attacks in Mobile ad-hoc networks

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    Mobile Ad-hoc Networks (MANETs) are a gathering of portable hosts which speak with each other with no focal system power or altered foundation. Because of its attributes like portability furthermore, heterogeneity ad-hoc networks are more defenseless to assaults. Black hole is an assault where every one of the bundles sent to assailant hub, by neighboring hubs, are dropped purposefully. In this thesis, we propose a secure learning calculation method which intends to identify and securing the black hole by considering the bundle drop reasons in needless mode. Presented AODV direction convention is adjusted to distinguish and securing the black hole assault. The investigation results demonstrate that our proposed calculation secure the AODV against black hole assault in MANETs

    Infrared Spectra of Potassium Citrate Monohydrate Single Crystals

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    Hydrophosphonylation of activated alkenes and alkynes via fluoride ion activation in ionic liquid medium

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    A simple transition metal-free hydro/hydrothiophosphonylation of Baylis-Hillman adducts, substituted allyl bromides, allenylphosphonates and alkynes, promoted by fluoride ion in ionic liquid, is described. Clear-cut evidence for fluoride activation of the phosphite via pentacoordinate phosphorus is provided for the first time. Also, in a comparative reaction, the product obtained was different from that from the palladium catalyzed one. Structures of key products are proven by X-ray crystallography
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