Silica aerogels as support for lipase catalyzed esterifications at sub- and supercritical conditionsZoran Novak
, Maja Leitgeb
, Vlasta Krmelj
, Željko Knez
, 2003, izvirni znanstveni članek
Opis: The enzymes (lipases from Candida rugosa and porcine pancreas) were immobilized on silica aerogels by sol-gel procedure followed by supercritical drying with CO2. Such immobilized enzymes were used as biocatalysts for esterification in supercritical CO2 and near critical propane at 40 °C and 100 bar. It was found out that the initial reaction rates in propane rose two to three times in comparison with the same reaction, catalyzed by free lipase. SC CO2 deactivated the non-immobilized lipase in reaction mixture while with the immobilized enzyme the conversion was 35%. The initial reaction rates in propane were 20 times higher than in water medium due to the properties of propane as a medium for esterification of fatty acids.
Ključne besede: chemical processing, biotechnology, esterification, immobilization of enzymes, supercritial CO2, propane, lipases, supercritical CO2 drying
Objavljeno v DKUM: 01.06.2012; Ogledov: 1668; Prenosov: 28
Povezava na celotno besedilo
Stimulating integral refurbishment principles in social housing as a challenge for sustainable development : case studyMetka Sitar
, Vesna Žegarac Leskovar
, Vlasta Krmelj
, 2009, objavljeni znanstveni prispevek na konferenci
Opis: Circumstances of climate changes have raised the awareness of the role housingconstruction activity plays in being one of the major stimuli of socio-economic processes in Slovenia. Further encouragement came through corresponding EU-strategies focusing not only on new housing constructions butalso on refurbishment and renewal of the existing stock, which has been rather neglected. Firstly, information on the Slovenian housing system along with institutional and governance changes - having taken place since 1991 - will be presented, particularly in terms of tenure and housing ownership. In the middle of the 1990s, fragmented ownership was regulated by the formation of condominiums as the basis of housing management and maintenance. Further on, special attention will be paid to newly introduced policies concerning energy efficiency of building constructions at the national level. In addition, the paper will concentrate on endeavours to refurbish the existing multi-family housing stock which represents the most problematic financial issue in terms of a long term investment perspective. Slovenia has in fact notdeveloped any special policies regarding refurbishment of the existing housing stock, either at the national, or at the local level. The housing development sector of the Municipality of Maribor is one of the most significant cases in Slovenia, as far as transition consequences to be effected in the social housing sector are concerned. However, the transformation from an old industrial town into a sustainable community was characterized by extreme complexity. Relying upon its own development strategies the local building construction sector succeeded in remaining one of the most dynamic economic activities of the town and the region. As a recommendation, ideas of energy renewal strategies and measures, based on the local energy concept and supported by financial mechanisms of public private partnership, will be discussed.
Ključne besede: Slovenia, Maribor, housing, refurbishment, energy efficiency, local energy concept, public intermunicipal housing fund
Objavljeno v DKUM: 31.05.2012; Ogledov: 2069; Prenosov: 78
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VPLIV PROMETA NA OKOLJE TER ZEMELJSKI PLIN KOT ALTERNATIVNO POGONSKO GORIVOAdrijana Copot
, 2011, diplomsko delo
Opis: Promet postaja eden največjih onesnaževalcev našega okolja, tako po svetu kot v Sloveniji. Največ težav povzroča v urbanih območjih. Posledice se kažejo v prometnih zastojih, hrupu, onesnaženosti zraka in povečanih vibracijah.
Ljudje bodo še vedno uporabljali osebna vozila kot osnovno prevozno sredstvo, zato iščemo okolju bolj prijazna - alternativna pogonska goriva, kar je tudi osrednja tema diplomske naloge. Ugotavljamo, da bi bilo najbolj ekološko in zdravju bolj prijazno se prevažati z avtomobili na vodik, v kolikor bi le-ta bil proizveden z uporabo električne energije, ki bi jo pridobili iz obnovljivih virov. Vendar dokler to ni možno, je prehodno primerno gorivo stisnjen zemeljski plin. Pri vožnji z vozili na zemeljski plin nastaja zelo malo izpušnih plinov in prašnih delcev skoraj ni.
Ključne besede: Promet, vplivi na okolje, emisije, alternativna goriva.
Objavljeno v DKUM: 27.09.2011; Ogledov: 2743; Prenosov: 301
Celotno besedilo (34,85 MB)