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NAPRAVA ZA DOZIRANJE ODPADNEGA MATERIALA S POLŽASTIM TRANSPORTERJEM
Peter Majerič, 2012, diplomsko delo

Opis: Odpadni material predstavlja vedno večji problem v družbi. Pri podjetju MD Inženiring d.o.o. so že projektirali nekaj centrov za ravnanje z odpadki, prav tako pa opravljajo raziskave na tem področju za nadaljnjo uporabo odpadkov. V tem diplomskem delu se je za to podjetje opravila zasnova naprave za doziranje odpadkov. Naprava je namenjena za več vrst odpadkov z različnimi lastnostmi in temu primerno mora biti zasnovana. Osnova naprave sta zalogovnik za odpadke in polžasti transporter. Slednji je bil zasnovan po priporočilih standarda DIN 15262. Ostali elementi naprave so bili zasnovani za nemoteno obratovanje transporterja. Za to delo so bili uporabljeni tudi programska orodja: Abaqus, za preračun nekaterih elementov naprave, in program Solidworks, za tridimenzionalno modeliranje naprave in kasnejšo izdelavo tehniške dokumentacije.
Ključne besede: Polžasti transporter za doziranje, odpadni material, zasnova naprave z zalogovnikom
Objavljeno: 23.05.2012; Ogledov: 1160; Prenosov: 268
.pdf Celotno besedilo (4,80 MB)

3.
Synthesis of Au nanoparticles prepared with ultrasonic spray pyrolysis and hydrogen reduction
Srečko Stopić, Bernd Friedrich, Sergej Tomić, Miodrag Čolić, Monika Jenko, Rebeka Rudolf, Peter Majerič, Jelena Bogovic, 2013, izvirni znanstveni članek

Opis: Golden nanoparticles of different sizes and shapes (spherical, cylindrical, triangular and round) where prepared during a synthesis of gold with ultrasonic spray pyrolysis (USP) and hydrogen reduction. The experimental investigations of the (USP) method were performed with an ultrasonic source of 0.8 MHz and 2.5 MHz, acting on the water solution of HAuCl4 forming aerosols with micron-sized and nanosized droplets. The results of the investigation show that the final shape and size of the Au particles depend on the characteristics of the solution and the frequency of the ultrasound. The second step of synthesizing the Au nanoparticles includes the subsequent thermal decomposition of the aerosol droplets in a hydrogen atmosphere between 260°C and 500°C. The investigations showed that the Au nanoparticles prepared in this way are smaller and more homogeneous.
Ključne besede: gold, ultrasonic spray pyrolysis, reduction, nanoparticles
Objavljeno: 21.12.2015; Ogledov: 607; Prenosov: 18
.pdf Celotno besedilo (3,17 MB)

4.
Morphology, aggregation properties, cytocompatibility and anti-inflammatory potential of citrate-stabilized AuNPs prepared by modular Ultrasonic Spray Pyrolysis
Rebeka Rudolf, Peter Majerič, Sergej Tomić, Mohammed Shariq, Urban Ferčec, Bojan Budič, Bernd Friedrich, Dragana Vučević, Miodrag Čolić, 2017, izvirni znanstveni članek

Opis: Ultrasonic Spray Pyrolysis (USP) possesses a great potential for production of higher quantities of gold nanoparticles (AuNPs), thus overcoming the problem of batch-to-batch variations in their properties. Recently, we demonstrated that USP with an additional evaporation chamber (modular USP) led to a better size control of AuNPs. However, their morphology, stability, toxicity, and immunomodulatory properties have not been investigated completely. Here, two types of spherical AuNPs were produced by using different USP parameters, followed by their stabilization in Na-citrate solution. No significant changes in their size, agglomeration, and -potential occurred 3 months after their initial production in citrate solution. However, the conditioning of AuNPs in serum-containing cell culture media for 24 h induced an increase in the AuNPs’ hydrodynamic size and a red shift in their Surface Plasmon Resonance, pointing to their instability in biological media. Cytocompatibility tests showed that the produced AuNPs were internalized by L929 cells and primary human monocytes and were not cytotoxic at the concentrations lower than 200 μg/mL, but they exhibited antiproliferative and anti-inflammatory effects, respectively. AuNPs reduced the percentage of CD14+CD16+ but not CD14lowCD16+ monocytes in vitro and reduced the expression of CD86, HLA-DR, TNF-α, and IL-12/IL-23 by these cells. These results indicate that the anti-inflammatory effects of citrate-capped AuNPs produced by modular USP could be beneficial for their application in the treatment of inflammatory conditions.
Ključne besede: Ultrasonic Spray Pyrolysis, gold nanoparticles, plasmon resonance, monocytes, antiinflammatory effects
Objavljeno: 14.06.2017; Ogledov: 236; Prenosov: 33
.pdf Celotno besedilo (5,41 MB)

5.
Au-nanoparticle synthesis via ultrasonic spray pyrolysis with a separate evaporation zone
Bernd Friedrich, Rebeka Rudolf, Peter Majerič, 2015, izvirni znanstveni članek

Opis: Some experiments were conducted in connection with the gold-nanoparticle production in an effort to produce a more accurate model for determining the gold-nanoparticle synthesis with a modified ultrasonic spray pyrolysis (USP). As previous experi- ments with gold nanoparticles yielded nanoparticles of various shapes (spherical, triangular, cylindrical, etc.), a focus on synthesizing only spherical nanoparticles is underway, as a mixture of different shapes is difficult to characterize and utilize. One of the factors for the particle formation is droplet evaporation. In an attempt to produce the optimum conditions for droplet evaporation with the solvent diffusion and precipitation, a separate furnace and a separate reaction-gas inlet were used. This modification separates the evaporation stage from the reaction stage, compared to the standard USP set-up. Using relatively low temperatures, from 60 °C up to 140 °C, for the evaporation stage provides for more time and better conditions for the diffusion of the solvent into the center of a droplet and a higher probability of forming a spherical particle.
Ključne besede: nanotehnology, ultrasonic spray pyrolysis, gold, aerosol, TEM microscopy
Objavljeno: 14.03.2017; Ogledov: 327; Prenosov: 39
.pdf Celotno besedilo (752,54 KB)

6.
Synthesis of NiTi/Ni-TiO[sub]2 composite nanoparticles via ultrasonic spray pyrolysis
Peter Majerič, Rebeka Rudolf, Ivan Anžel, Jelena Bogovic, Srečko Stopić, Bernd Friedrich, 2015, izvirni znanstveni članek

Opis: In this paper we present the production of NiTi/Ni-TiO2 composite nanoparticles via the synthesis method called ultrasonic spray pyrolysis (USP). The precursor solution for the synthesis of spherical NiTi particles was prepared from an orthodontic wire with a chemical composition of Ni (amount fraction x = 51.46 %) and Ti (x = 48.54 %). TEM microscopy, in combination with EDX analyses, was used for a detailed characterization of the obtained NiTi nanoparticles. The results showed the nanoparticle sizes ranging from 60 nm to 600 nm, depending on the parameters of the production procedure. This showed the versatility of the new USP synthesis procedure, proving its usefulness for different materials and applications.
Ključne besede: ultrasonic spray pyrolysis, NiTi/Ni-TiO2 composite nanoparticles, characterization, Transmission electron microscope (TEM), TEM microscopy
Objavljeno: 23.03.2017; Ogledov: 384; Prenosov: 36
.pdf Celotno besedilo (1,13 MB)

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Sinteza nanodelcev zlata z modificirano ultrazvočno razpršilno pirolizo
Peter Majerič, 2016, doktorska disertacija

Opis: Doktorsko delo predstavlja študije, eksperimentalno delo, tehnike karakterizacije, rezultate in analize, s katerimi je povezana sinteza čistih, okroglih, neaglomeriranih nanodelcev zlata (AuNPs) z velikostjo okoli 50 nm. V prvem delu raziskav smo sintetizirali AuNPs s konvencionalno ultrazvočno razpršilno pirolizo (USP). Za surovino smo uporabili tetrakloroaurično kislino HAuCl4(s), ki smo jo raztopili v vodi. To raztopino smo v komori z ultrazvokom razpršili v kapljice, ki jih je nosilni plin N2 prenesel v reakcijsko peč. V tej peči so potekale stopnje sinteze: izhlapevanje kapljic, toplotna dekompozicija, redukcija s plinom H2 in zgoščevanje. Nastali so AuNPs različnih oblik z velikostmi do 300 nm, pri čemer smo identificirali visoko stopnjo aglomeracije. Ker s konvencionalnim USP nismo dosegli cilja, smo postavili hipotezo, da lahko izdelamo ciljne AuNPs z modificiranim USP, kjer je cona izhlapevanja kapljic ločena od reakcijske peči, reducirni plin pa je uveden neposredno v reakcijsko peč. Za potrditev hipoteze smo z eksperimenti preučevali vplivne parametre USP-sinteze: koncentracijo Au v začetni raztopini, temperature v coni izhlapevanja kapljic in v reakcijski peči ter pretok plinov N2 in H2. S pomočjo tehnik karakterizacij (TEM, DLS, ICP) na nastalih AuNPs smo ugotovili, da pri USP-sintezi hkrati potekata dva mehanizma nastanka nanodelcev (»kapljica-v-delec«, DTP in »plin-v-delec«, GTP). Z DTP nastajajo veliki nanodelci – do 300 nm, z GTP pa majhni – do 50 nm. Kadar potekata oba mehanizma hkrati, dobimo neugodno bimodalno velikostno porazdelitev AuNPs. Na tej osnovi smo postavili model nastanka AuNPs, ki pojasnjuje, kako lahko pri USP-sintezi s spreminjanjem koncentracije Au v začetni raztopini in pretokov plinov vplivamo na DTP in GTP mehanizma nastanka v korist GTP. S ciljno izbranimi parametri (0,5 g/l Au, 4,5 l/min N2, 2,0 l/min H2) smo ustvarili pogoje za nastanek AuNPs z GTP-mehanizmom. Pri tem so nastali okrogli AuNPs z ozko velikostno porazdelitvijo (37,0 ± 5,5 nm). Tako smo potrdili pravilnost postavljenega modela in hipotezo, da lahko z modificiranim USP izdelamo AuNPs ciljnih lastnosti.
Ključne besede: modificirana ultrazvočna razpršilna piroliza, nanodelci zlata, mehanizmi nastanka, karakterizacija
Objavljeno: 08.06.2016; Ogledov: 805; Prenosov: 44
.pdf Celotno besedilo (7,14 MB)

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