228 research outputs found
Raziskovanje genetske diverzitete velikega klobučnjaka (Rhizostoma pulmo) z orodji molekularne taksonomije
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Recycling of glass fiber reinforced composites waste
No full textZ razvojem tehnologije se veča potreba po kompozitnih materialih, saj jih odlikuje njihova visoka trdnost, togost in majhna teža. Kompozitne materiale pa ni enostavno reciklirati, zato je pomembno, da se nenehno išče rešitve kako preprečiti odlaganje odsluženih kompozitnih materialov na odlagališčih. Namen magistrskega dela je recikliranje treh različnih odpadnih kompozitov ojačanih s steklenimi vlakni, s postopkom pirolize z in brez dodatka katalizatorja.
Delo je zajemalo izvajanje postopka termične in katalitične pirolize, čiščenje izpadlih vlaken, čiščenje trdnega ostanka z oksidacijo, gravimetrično analizo nastalih produktov in karakterizacijo trdnih in tekočih produktov z IR spektroskopijo.
Ugotovili smo, da je dodatek katalizatorja vzorcu 2 zvišal temperaturo in skrajšal čas reakcije. Za namen pridobivanja tekočega produkta je najbolj primeren vzorec 1, saj smo za le-tega z istimi pogoji pridobili največ tekočega produkta. Za namen pridobivanja trdnega ostanka pa je najbolj primeren vzorec 2, saj smo z njim pridobili najboljše rezultate. Dodatek katalizatorja ni povečal nastanka tekočega produkta, saj so deleži kataliziranih TP najmanjši.With the development of technology, the need for composite materials is increasing, as they are distinguished by their high strength, stiffness and low weight. However, composite materials are not easy to recycle, so it is important to constantly research and find solutions to prevent the disposal of used composite materials in landfills. The purpose of the master\u27s thesis is the recycling of three different glass fibre reinforced composites waste using pyrolysis with and without the addition of a catalyst.
The work included the implementation of thermal and catalytic pyrolysis process, purification of dropped fibers, purification of solid residue by oxidation at high temperature, gravimetric analysis and characterization of solid and liquid products by IR spectroscopy.
The addition of catalyst to sample 2 raised the temperature and shortened the reaction time. For the purpose of obtaining a liquid product, is the most suitable sample 1, as we obtained the most liquid product under the same conditions. For the purpose of obtaining glass fibre, is the most suitable sample 2, as we obtained the best results with it. The addition of catalyst did not stimulate the formation of liquid product
Extraction of chestnut bark with subcritical water
No full textBiomasa predstavlja naravni vir vrednih komponent. Lubje kostanja vsebuje visoke vsebnosti taninov in različne fenolne spojine, ki se uporabljajo v medicini ter farmacevtski, kozmetični in prehrambeni industriji. Namen diplomskega dela je bil separirati vredne spojine iz lubja kostanja s subkritično vodo in optimizirati proces z uporabo metode odzivnih površin z zasnovo Box-Behnkenovega načrtovanja. Optimizirali smo tri ključne spremenljivke, in sicer temperaturo, čas in razmerje topilo/material, ter spremljali njihov vpliv na ekstrakcijski izkoristek in vsebnost vrednih komponent v lubju, kot so totalni fenoli, totalni tanini in antioksidativna aktivnost. V lubju smo dokazali prisotnost elagne in galne kisline, elagotaninov (veskalagin, kastalagin, 1-o-galoj kastalagin), sladkorjev (maltoza, glukoza, fruktoza in arabinoza) ter njihovih derivatov (5-HMF, furfural in levulinska kislina). Zadnji korak v diplomskem delu je bil določitev optimalnih pogojev, s katerimi bi dosegli najvišjo vsebnost elagne kisline ter zadovoljive vsebnosti totalnih fenolov in totalnih taninov.Biomass represents the natural source of valuable compounds. Chestnut bark contains high level of tannins and various phenolic compounds which can be utilized in medicine and pharmaceutical, cosmetic, and food industry. The aim of this work was optimization of subcritical water extraction process of chestnut bark using Box-Behnken response surface method. The influence of process parameters, such as temperature, extraction time and solid-solvent ratio, on extraction yield, yield of the main compounds, total phenol content, total tannin content and antioxidant activity was observed. The identified compounds were ellagic and gallic acid, ellagitannins (vescalagin, castalagin, 1-o-galloyl castalagin), sugars (maltose, glucose, fructose and arabinose) and sugar derivatives (5-HMF, furfural and levulinic acid). The final step of the work was determination of the optimal conditions of the process to obtain the bark extract highly rich in ellagic acid and with satisfactory level of total phenols and total tannins
Ocene in stališča zaposlenih na centrih za socialno delo do sodelovanja s policisti - študija primera : diplomsko delo
No full textVpliv gospodarske krize na zaposlovanje mladih v Sloveniji in primerjava z Veliko Britanijo
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The possibility of using biogas for methanol production
No full textV industrijskih obratih poteka proizvodnja metanola pri visokem, srednjem in nizkem tlaku.
V okviru diplomskega dela smo opravili del raziskovalne študije proizvodnje metanola po nizkotlačnem Lurgijevem postopku za Nafto Petrochem d.o.o., v kateri je bila naša glavna naloga primerjava proizvodnje metanola iz različnih surovin - zemeljskega plina in bioplina. Raziskovalno študijo smo izvedli z računalniškim procesnim simulatorjem Aspen Plus z modelom, ki vključuje kemijsko termodinamiko za realne procese.
S podrobno analizo smo preučili, kateri parametri najugodneje vplivajo na povečanje proizvodnje metanola, da bi lahko bila surovina, kot je bioplin, primerljiva z zemeljskim plinom.
Ugotovili smo, da je proizvodnja surovega metanola iz bioplina primerljiva z zemeljskim plinom, če zvišamo temperaturo in znižamo tlak v reformerju.In industrial plants the production of methanol takes place at high, medium and low pressure.
A part of a research study conducted methanol production process using Lurgi low pressure procedure, for Nafta Petrochem Ltd. Our main task was to compare the value of metanol from natural gas, and from the biogas. The research study was performed by means of the computer process simulator Aspen Plus with the model, which includes chemical thermodynamics for real processes.
With the detailed analysis we have examined which parameters affect more favorable to increase the production of methanol, so that the biogas could be comparable to natural gas.
We found that the production of crude methanol from biogas is comparable to natural gas at the increased temperature and decreased pressure in the reformer
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