Search results for " Yield"
showing 10 items of 550 documents
Optical and amplified spontaneous emission of neat films containing 2-cyanoacetic derivatives
2018
During the last two decades, small organic molecules have been widely studied for potential applications in organic solid-state lasers due to low-cost production, simple processing possibility and physical property tuning ability through chemical structure synthetic modifications. One of the most investigated and applied compound in dye lasers is 4- (dicyanomethylene)-2-methyl-6-(4-dimethylaminostyryl)-4H-pyran (DCM). It has shown remarkable properties as a dye in solid-state lasers. One of the drawbacks of this compound is high intermolecular interactions which reduce emission efficiency. Therefore it can be applied only in doped systems in low concentration (around 2 wt%). Recently we hav…
Stimulated emission and optical properties of pyranyliden fragment containing compounds in PVK matrix
2017
This work has been supported by National Research program “Multifunctional materials and composites, photonics and nanotechnology (IMIS2)”. Financial support provided by Scientific Research Project for Students and Young Researchers No. SJZ2015/12 realised at the Institute of Solid State Physics, University of Latvia is greatly acknowledged.
Effect of substrate improvement on optimising biogas yield from anaerobic digestion
2014
Masteroppgave i fornybar energi ENE 500 Universitetet i Agder 2014 The anaerobic digestion process involves the decomposition of the organic matter to yield biogas; gas that is mainly composed of methane and carbon dioxide with traces of some other gases. This process is used for different purposes including municipal waste treatment, wastewater treatment, fertilizer production, and farm wastes disposal as well as energy production. It is accomplished in three main stages; hydrolysis, acidogenesis and methanogenesis with each of the stages achieved by specific microorganisms that are active in limited ranges of operational and environmental conditions. These conditions are controlled to ach…
Rate of photon absorption and turnover number: two parameters for the comparison of heterogeneous photocatalytic systems in a quantitative way
1993
Abstract In order to correctly compare the performance of different photocatalytic systems using polycrystalline semiconductor oxides, two parameters are proposed: the rate of photon absorption (rpa) and the turnover number (tn). From these quantities the quantum yield (qy), which indicates the efficiency of the absorbed photons for promoting a reaction event, can be determined. The phenol photodegradation reaction, carried out in aqueous dispersions of polycrystalline TiO2 (anatase) of different preparation methods and sources, has been used as “test reaction” in order to determine the tn, rpa and qy values.
ChemInform Abstract: Rate of Photon Absorption and Turnover Number: Two Parameters for the Comparison of Heterogeneous Photocatalytic Systems in a Qu…
2010
Abstract In order to correctly compare the performance of different photocatalytic systems using polycrystalline semiconductor oxides, two parameters are proposed: the rate of photon absorption (rpa) and the turnover number (tn). From these quantities the quantum yield (qy), which indicates the efficiency of the absorbed photons for promoting a reaction event, can be determined. The phenol photodegradation reaction, carried out in aqueous dispersions of polycrystalline TiO2 (anatase) of different preparation methods and sources, has been used as “test reaction” in order to determine the tn, rpa and qy values.
Comparison of selection criteria for milk yield traits of Valle del Belice dairy sheep.
2006
Abstract The objectives of this work were to investigate alternative selection criteria for milk yield traits in the Valle del Belice sheep breed, which are either corrected for lactation length or not affected by lactation length, to estimate genetic parameters for these alternative selection criteria and to compare the estimated breeding values. The genetic correlations show that corrected milk yield (CMY), maximum test-day yield (MTY) and milk yield at hundred days (MYH), are moderately or weakly correlated with lactation length (LL) ( r g = 0.58, 0.16 and 0.39, respectively). Higher genetic correlation was found between total milk yield (TMY) and LL ( r g = 0.73). Rank correlations be…
3,4-Dihydro-2H-pyrrole-2-carbonitriles: Useful Intermediates in the Synthesis of Fused Pyrroles and 2,2′-Bipyrroles
2016
Various heterocyclic structures containing the pyrrole moiety have been synthesized from easily accessible 3,4-dihydro-2H-pyrrole-2-carbonitriles in one-pot procedures. 5,6,7,8-Tetrahydroindolizines, 2,3-dihydro-1H-pyrrolizines as well as 6,7,8,9-tetrahydro-5H-pyrrolo[1,2-a]azepines were obtained from these precursors in high yields in an alkylation/annulation sequence. The same conditions were applied in the synthesis of a 5,8-dihydroindolizine, which could easily be transformed to the corresponding indolizine by dehydrogenation. Furthermore, oxidative couplings of 3,4-dihydro-2H-pyrrole-2-carbonitriles with copper(II)-salts furnished 2,2'-bipyrroles as well as 5,5'-bis(5-cyano-1-pyrroline…
A Xylochemically Inspired Synthesis of Lamellarin G Trimethyl Ether via an Enaminone Intermediate.
2019
A concise high yielding synthesis of lamellarin G trimethyl ether has been achieved from precursors and solvents that can in principle be derived from xylochemical (woody biomass) sources. The route is comparatively green in that some reactions are performed without solvent or with relatively benign solvents. In addition, chromatographic purification of products is avoided, and only a single aqueous workup is performed. The novelty of the synthesis lies in the intermediacy of an enaminone for the construction of the central pyrrole ring. The overall yield of the product is among the highest reported to date.
Synthesis and structure of a new organometallic polyoxomolybdate,
2004
Abstract Acidic aqueous solutions of the [Cp*MoO2(H2O)x]+ ion yield single crystals of the novel organometallic polyoxomolybdate Cp 2 ∗ Mo 6 O 17 via a slow protonolysis of the Mo–Cp* bond. This compound has subsequently been obtained selectively and in good yields from the combination of Cp 2 ∗ Mo 2 O 5 and four equivalents of MoO 4 2 - under acidic conditions. The X-ray structure of Cp 2 ∗ Mo 6 O 17 is analogous to other hexanuclear polyoxometallate ions but is the most distorted so far reported according to the continuous symmetry measure, the inner (μ6-O)Mo6 core featuring a large displacement of the central oxygen atom toward the organometallic moieties and away from the inorganic ones.
Monsoon Multidisciplinary Analysis (AMMA) : an integrated project for understanding of the West African climate system and its human dimension
2011
International audience; The intraseasonal time scale is critical in West Africa where resources are highly rainfall dependent. Three main modes of variability have been identified, two with a mean periodicity of 15 days and one with a mean periodicity around 40 days. These modes have a regional scale and can strongly influence precipitation and convective activity. They are mainly controlled by atmospheric dynamics and land-surface interactions. They can also modulate the very specific phase of the African summer monsoon onset. A better knowledge of the mechanisms controlling this scale is necessary to improve its predictability.