Search results for "Biomas"
showing 10 items of 980 documents
Microwave-assisted conversion of novel biomass materials into levulinic acid
2018
Levulinic acid is considered one of the most important platform chemicals. It is currently produced mainly from lignocellulosic biomasses. However, there are also other abundant biomass materials, which could be used as raw materials for levulinic acid production. In this work, levulinic acid was produced from two novel biomasses in the presence of Brønsted (H2SO4) and Lewis acid (CrCl3·6H2O or AlCl3·6H2O) catalysts. The studied materials were carbohydrate-rich potato peel waste and sporocarps of the fungus Cortinarius armillatus. Reaction conditions, i.e., time, temperature, H2SO4, and Lewis acid concentrations, were studied by utilizing full 24-factorial experimental designs. Microwave ir…
Particle chemical properties in the vertical column based on aircraft observations in the vicinity of Cape Verde Islands
2011
During the second Saharan Mineral Dust Experiment (SAMUM-2) field campaign, particles with geometric diameters (d) between ∼0.1 and 25 μm were collected on board of the Deutsches Zentrum für Luft- und Raumfahrt (German Aerospace Center, DLR) Falcon aircraft. Size, chemical composition and mixing state of aerosols sampled (spatially and vertically resolved) along the West African coastline and in the Cape Verde Islands region were determined by electron microscopy. A pronounced layer structure of biomass-burning aerosol and desert dust was present for all days during the sampling period from 23 January to 6 February. The aerosol composition of the small particles (d < 0.5 μm) was highly v…
Slāpekļa mēslojuma ietekme uz zemsedzes veģetāciju skujkoku audzēs uz minerālaugsnēm
2019
Mežsaimniecība ir viena no svarīgākajām tautsaimniecības nozarēm Latvijā, tāpēc ir svarīgi veikt pareizu mežu apsaimniekošanu, paaugstinot to ražību tai pat laikā nenodarot būtiskus kaitējumus apkārtējai videi. Maģistra darba mērķis ir pētīt slāpekļa mēslojuma ietekmi uz meža zemsedzes veģetāciju skujkoku audzēs uz minerālaugsnēm Kalsnavas mežu novadā. Darbā aplūkoti dažādi vides piesārņojuma veidi, to izplatība un ietekme uz vides procesiem. Maģistra darba izstrādei, sadarbībā ar LVMI Silava pētniekiem, izraudzīti 4 objekti, kur koku augšanas apstākļu uzlabošanai izmantots slāpekļa mēslojums. Zemsedzes veģetācijas analizēšanai izvēlētas 5 audzes LVMI Silava un LLU valsts zinātniskās izpēte…
Greater mitochondrial energy production provides resistance to ocean acidification in "winning" hermatypic corals
2021
Coral communities around the world are projected to be negatively affected by ocean acidification. Not all coral species will respond in the same manner to rising CO2 levels. Evidence from naturally acidified areas such as CO2 seeps have shown that although a few species are resistant to elevated CO2, most lack sufficient resistance resulting in their decline. This has led to the simple grouping of coral species into “winners” and “losers,” but the physiological traits supporting this ecological assessment are yet to be fully understood. Here using CO2 seeps, in two biogeographically distinct regions, we investigated whether physiological traits related to energy production [mitochondrial e…
Nuovi Catalizzatori Sol-Gel per la Chimica Fine e la Valorizzazione della Biomassa
2014
Gazifikācijas modeļa pētijumi
2018
Darbā ir izveidots un analizēts matemātiskais modelis biomasas gazifikācijai ar nelineāru diferenciālvienādojumu sistēmu. Pirmkārt, tiek iegūta parasto diferenciālvienādojumu sistēma. Simulācijas tiek veiktas, izmantojot Runges-Kutas ar 4. kārtas punktu šablonu un iebūvēto funkciju programpaketē MATLAB. Tika izveidots reālistisks modelis ar daļēju parciālo diferenciālvienādojumu. Telpiskā diskretizācija tiek veikta, izmantojot galīgo tilpuma metodi. Izmantojot programmu MATLAB tika veiktas simulācijas vairākiem gazifikācijas procesu scenārijiem. Optimālākam rezultātu novērtējumam papildus apskata un ilustrē piemēru sērkociņu degšanai un to atkarībai no izvēlētajiem parametriem.
Influence of torrefaction pretreatment on the pyrolysis of Eucalyptus clone: A study on kinetics, reaction mechanism and heat flow
2016
Abstract The adverse nature of biomass requires specific pretreatment processes to better utilize it in bioenergy applications, and torrefaction is one of the most recognized thermal pretreatment methods. In this regard, we studied the effect of torrefaction pretreatment on kinetics, reaction mechanism and heat flow during the pyrolysis of biomass by making a comparative analysis between the pyrolysis of dried and torrefied Eucalyptus wood. Torrefied biomass was produced at three temperatures, namely 250, 275 and 300 °C. Pyrolysis was performed at 700 °C. The char yield during pyrolysis increased from 22.39 percent to 36.34 percent when the torrefaction temperature was increased from 250 to…
Carbon biomass planktonic-periphytic organisms of a mesocosm experiment [Dataset]
2020
Este documento presenta los datos de biomasa en carbono (mgC m-2) de taxones planctónicos y perifíticos de un experimento a escala de mesocosmos. La comunidad planctónica-perifítica fue sometida a tres escenarios de cambio global, con la temperatura y la radiación ultravioleta como factores experimentales testados independientemente. Cada elemento de la comunidad fue identificado a la máxima resolución taxonómica posible. Las abreviaciones y explicaciones sobre los escenarios experimentales, las replicas de cada escenario y los detalles de los compartimentos considerados en cada mesocosmos se muestran en la primera página de este documento. This document presents the data about carbon bioma…
Tiellä kohti uusien energiateknologioiden kaupallistumista : eri toimijoiden näkemyksiä puubiomassaa polttoaineenaan käyttävien pien- ja mikro-kokolu…
2011
Tässä laadullisessa tutkimuksessa selvitettiin puubiomassaa polttoaineenaan käyttävien pien- ja mikro-kokoluokan CHP-teknologioiden innovaatioprosessiin, erityisesti kaupallistamiseen ja markkinoilla yleistymiseen, liittyviä edistämistekijöitä ja esteitä. Tutkimusaineisto koottiin haastattelemalla 10 eri toimijaa, jotka edustivat kattila- ja laitevalmistajia, korkeakouluja, tutkimuslaitoksia, julkisia rahoittajia sekä kehitysyhtiöitä. Haastateltavilta kysyttiin heidän näkemyksiään tarkasteltavien energiateknologioiden innovaatioprosessiin vaikuttavista edistämistekijöistä ja esteistä viidestä eri näkökulmasta: poliittisesta, taloudellisesta, sosiaalisesta, teknologisesta ja ympäristötekijöi…
Responses of zooplankton to cane sugar additions to a small humic lake, Alinen Mustajärvi
2010
The response to projected increase in dissolved organic carbon (DOC) loading to boreal lakes is being studied in lake Alinen Mustajärvi, a small humic lake in southern Finland, where labile DOC concentration has been artificially increased during 2008 and 2009 by monthly additions of cane sugar. As part of this wider project, in this thesis the responses of the zooplankton community to cane sugar addition were studied. Zooplankton samples were collected monthly in the ice-free periods of 2007, 2008 and 2009 and the mean densities and mean carbon biomasses of rotifers and crustacean zooplankton (cladocerans and copepods) were calculated. Stable isotope analyses (δ13C and δ15N) were made for …