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1.
Fragmentacija vlaken iz melaminskih eterificiranih smol v naravnem okolju
Nina Podlesnik, 2020, undergraduate thesis

Abstract: Vlakna iz melaminske eterificirane smole imajo specifične lastnosti, kot so nizka toplotna prevodnost, odlična toplotna stabilnost do okoli 300 °C (material se ne tali, kaplja ali krči), visoka kemijska in UV odpornost. Zaradi svojih lastnosti so vlakna uporabna v številnih industrijskih aplikacijah, kot na primer za ognjevarne zaščitne obleke, za filtrni medij visoke zmogljivosti in učinkovitosti, za izolacije itd. Vprašanje pa je kaj narediti s proizvodom po končani življenjski dobi zaradi njegove termične stabilnosti in strukture ter kakšen je vpliv vlaken na okolje. Plastični odpadki negativno vplivajo na zdravje ljudi in živali ter onesnažujejo okolje. V diplomski nalogi smo opazovali kaj se zgodi z vlakni po krajši izpostavljenosti v naravnih okoljih. Osredotočili smo se na izpostavljenost materiala v zemlji in v vodah. Pri izpostavljenosti vlaken v zemlji smo opazovali vizualne spremembe, spremembo mase ter izvedli IR spektroskopijo. Pred in po izluževanju vlaken v naravne vode (sladke in slane) pa smo merili vsebnosti amonijaka, formaldehida, celotnega dušika in ogljika, vrednost kemijske potrebe po kisiku (KPK) in osnovne parametre onesnaženosti vode (motnost, prevodnost in pH). Dodatno smo izvedli eksperiment z modelnimi vodami, pri čemer smo analizirali kako vpliva slanost ter pH na izluževanje materiala. Rezultati kažejo, da se vlakna pri poskusu z zemljo niso kaj dosti spremenila, kot smo tudi predvidevali, saj so bila v zemlji le relativno kratek čas. V nasprotju s predvidevanji, pa smo v vodah izmerili večje spremembe, zlasti večje povišanje koncentracije formaldehida.
Keywords: vlakna iz melaminske eterificirane smole, mikroplastika in nanoplastika, onesnaževanje okolja, izluževanje, plastični odpad, fragmentacija pastike v naravnem okolju.
Published: 08.10.2020; Views: 186; Downloads: 33
.pdf Full text (2,35 MB)

2.
Multi-objective synthesis of company’s supply-networks based on integration of renewable resources
Annamaria Vujanović, 2017, doctoral dissertation

Abstract: The aim of this doctoral dissertation was to develop a general methodology for sustainable integration of company's supply networks into nearby regional networks by i) integrating renewables, thereby increasing company's energy self-sufficiency, ii) by performing multi-objective synthesis in order to obtain economically efficient and yet environmentally benign or even unburdening solutions, and iii) to perform dynamic and stochastic synthesis under uncertainties in dynamically changing market conditions in order to obtain more reliable and realistic solutions. The research work is directly interlinked with a large-scale European meat producing company Perutnina Ptuj d.d., which is located in the heart of Slovenia. The aim of the first part was to integrate renewables into companies’ supply-networks at regional level in order to maximize the self-sufficiencies of their energy supplies. This concerns companies’ activities from the use of natural resources to supplying their final products to the customers being interlinked with their regional networks. A Mixed-Integer Linear Programming (MILP) model has been developed for the integration of both the companies’ and surrounding regional supply-networks and the utilization of different types of renewables as sources for the companies’ energy supplies. The potential renewable energy sources, which are located within companies surrounding region are solar, biomass, organic and animal wastes. The result indicates that by sufficient integration of renewables into companies’ supply networks, profitable and yet energy self-sufficient solutions can be obtained. The second part presents the multi-objective synthesis of a company’s supply-network by integrating renewables and accounting for several environmental footprints. A previously developed model for achieving energy self-sufficiency by integrating renewables into companies’ supply-networks has been extended for the evaluation of environmental impacts, such as energy, carbon, nitrogen, and water footprints. The achievement of an energy self-sufficient supply-network has been considered whilst significantly reducing environmental impacts. Direct (burdening) and indirect (unburdening) effects that form total effects on the environment are considered for the evaluation of environmental footprints. This approach identifies those alternative energy production technologies that are more profitable and environmentally more benign with significant unburdening capabilities. The results showed significant unburdening of the environment in terms of carbon and nitrogen footprints; however, higher burdening in terms of the water footprint. The third part presents a multi-objective MILP synthesis of a dynamic supply-network under uncertainty applied to the company. The previously-developed multi-objective model for achieving energy self-sufficiency by integrating renewables into companies’ supply-networks has now been extended to account for the dynamic consideration of variable supply and demand over the year, for uncertainties related to products’ demand and sun radiation, and for multi-objective optimisation, in order to obtain the most sustainable company’s supply-network. The sustainable synthesis of a company’s network is performed regarding the integration of the renewables such as biomass and other wastes, and solar energy. The obtained solutions are those reflecting maximal profit, reflecting constantly-changing dynamic market conditions, accounting for several uncertain parameters, and protecting the environment.
Keywords: Company's supply network, Renewables, Environmental Impacts, Dynamic synthesis, Flexibility, Multi-objective optimisation, Uncertainty
Published: 21.07.2017; Views: 968; Downloads: 118
.pdf Full text (1,89 MB)

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