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1.
Does the development of alternative energy technologies allow for new forms of coopetition?
Ante Galich, Lutz Marz, 2012, izvirni znanstveni članek

Opis: The article at hand illustrates how new types of coopetition emerge in the transformation of large technical systems. It builds on the latest literature on coopetition and highlights diverse institutional arrangements for coopetition, their effects on the actual innovation and the potential benefits for the firms involved. In contrast to many incremental innovations, the transformation of large technical systems requires the cooperation of many diverse actors as various resources are needed. This does not only open up the opportunity of new private-private or public-private cooperations but also brings about various new forms of commonly performed practices.
Ključne besede: hydrogen and fuel cells, coopetition
Objavljeno: 29.11.2017; Ogledov: 539; Prenosov: 254
.pdf Celotno besedilo (807,73 KB)
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2.
Two new zinc(II) acetates with 3- and 4-aminopyridine
Brina Dojer, Andrej Pevec, Ferdinand Belaj, Matjaž Kristl, 2015, izvirni znanstveni članek

Opis: The synthesis and characterization of two new zinc(II) coordination compounds with 3- and 4-aminopyridine are reported. They were obtained after adding a water solution of $Zn(CH_3COO)_2$ · $2H_2O$ or dissolving solid $Zn(CH_3COO)_2$ · $2H_2O$ in methanol solutions of 3- and 4-aminopyridine. The products were characterized structurally by single-crystal X-ray diffraction analysis. Colourless crystals of the compound synthesized by the reaction of $Zn(CH_3COO)_2$ · $2H_2O$ and 3-aminopyridine (3-apy), are built of trinuclear complex molecules with the formula $[Zn_3(O_2CCH_3)_6(3- apy)_2(H_2O)_2]$(1). The molecules consists of two terminal $Zn$ atoms, coordinated tetrahedrally, and one central $Zn$ atom, coordinated octahedrally. Colourless crystals, obtained by the reaction of $Zn(CH_3COO)_2$ · $2H_2O$ with 4-aminopyridine (4-apy), consist of a mononuclear complex $[Zn(O_2CCH_3)_2(4-apy)_2]$(2). Hydrogen-bonding interactions in the crystal structures of both complexes are reported.
Ključne besede: zinc(II) acetate dihydrate, aminopyridine, x-ray crystal structure, hydrogen bonds
Objavljeno: 30.08.2017; Ogledov: 748; Prenosov: 74
.pdf Celotno besedilo (1,06 MB)
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3.
Synthesis, crystal structure and magnetic properties of a new hydroxylammonium fluoroferrate
Brina Dojer, Matjaž Kristl, Zvonko Jagličić, Amalija Golobič, Marta Kasunič, Mihael Drofenik, 2012, izvirni znanstveni članek

Opis: This paper reports on the synthesis of a new hydroxylammonium fluoroferrate, with the formula $(NH_3OH)_3FeF_6$, obtained after dissolving iron powder in hydrofluoric acid and adding solid $NH_3OHF$. This new compound has been characterized by chemical and thermal analysis, single-crystal X-ray diffraction, and magnetic measurements. The title compound crystallizes trigonal, R3c, with cell parameters a = 11.4154(2) Å, c = 11.5720(2) Å, Z = 6. The structure consists of $NH_3OH^+$ cations and isolated $FeF_6^{3–}$ octahedra in which the central ion lies on a threefold axis. The oxygen and nitrogen atoms of the hydroxylammonium cations are donors of hydrogen bonds to fluoride anions, resulting in a network of hydrogen bonds between counterions. The effective magnetic moment $µ_{eff}$ = 5.8 BM was calculated and perfectly matches the expected value of high-spin Fe(III) ions. The thermal decomposition of the compound was studied by TG, DSC, and X-ray powder diffraction.
Ključne besede: inorganic chemistry, crystallography, coordination compounds, synthesis, crystal structure, characterization of compounds, determination of the structure of compounds, X-ray diffraction, magnetic measurements, thermal analysis, TG, DSC, hydrogen bond, metal complexes, hydroxylammonium fluoromethalatehydroxylammonium, fluoroferrate
Objavljeno: 25.08.2017; Ogledov: 1145; Prenosov: 51
.pdf Celotno besedilo (198,42 KB)
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4.
Magnetic field effects on redox potential of reduction and oxidation agents
Mojca Božič, Lucija Črepinšek-Lipuš, Vanja Kokol, 2008, izvirni znanstveni članek

Opis: Redox potentials of two reducing (sodium dithionite and glucose) and two oxidizing (hydrogen peroxide and sodium hypochlorite) agents were monitored at various concentrations and at different temperatures for 30-75 minutes after the exposure of their water solutions (glucose and hypochlorite solutions once; sodium dithionite and hydrogen peroxide solutions one, two and/or three-times) to the static magnetic field of flux density of 0.9 V s M-2 . The aim of the investigation was to suggest improvements, i.e., intensification and stability, of the reduction-oxidation ability of selected agents applicable in textile fibre processing, primarily bleaching and vat dyeing. Results of the experiments show that magnetic treatment (of solutions) raises both the reducing ability of glucose and the oxidation ability of hydrogen peroxide and sodium hypochlorite, promising some technological and economical benefits for the textile industry as well as forother fields of chemistry.
Ključne besede: magnetic water treatment, sodium dithionite, glucose, hydrogen peroxide, sodium hypochlorite, redox potential, textile vat processing
Objavljeno: 05.07.2017; Ogledov: 563; Prenosov: 71
.pdf Celotno besedilo (206,88 KB)
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5.
Decolorization and mineralization of reactive dyes, by the $H_2O_2$/UV process with electrochemically produced $H_2O_2$
Tina Jerič, Roel J. M. Bisselink, Willy Van Tongeren, Alenka Majcen Le Marechal, 2013, izvirni znanstveni članek

Opis: Decolorization of Reactive Red 238, Reactive Orange 16, Reactive Black 5 and Reactive Blue 4 was studied in the UV/$H_2O_2$ process with $H_2O_2$ being produced electrochemically. The experimental results show that decolorization increased considerably when switching on the electrochemical production of $H_2O_2$. Complete decolorization (>99%) was achieved for all dyes under the applied experimental conditions, partial mineralization (49-85%) was obtained, which depends on the type of dye. Reactive Red 238 was used to investigate operational parameters and it was found that decolorization was influenced by the applied electrical current of the electrochemical cell and flow rate. Decolorization and mineralization of Reactive Red 238 can be described by pseudo-first order kinetics. It was found that the initial concentration of Reactive Red 238 has a negative influence on the pseudo-firstorder reaction constant.
Ključne besede: decolorization, hydrogen peroxide, reactive dyes, in-situ $H_2O_2$, AOP, Reactive Red 238
Objavljeno: 10.07.2015; Ogledov: 883; Prenosov: 46
.pdf Celotno besedilo (195,10 KB)
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6.
7.
CATALYTIC GENERATION OF HYDROGEN FROM BIOMASS DERIVED LACTIC ACID VIA AQUEOUS PHASE REFORMING
Monika Bosilj, 2015, magistrsko delo

Opis: Hydrogen production from aqueous phase reforming (APR) of organic acids in aqueous phase and from residue of a biomass decomposition process over 3 wt% Pt/ZrO2 has been studied in the absence and presence of barium ions. The results have been compared with Pt/TiO2, Pt/C and Ni/C catalysts. Having identified barium hydroxide as a promising reagent in combination with Pt/ZrO2 catalyst for the hydrogen production out of organic acids, the method for the lactic acid conversion was extended. Lactic acid (LA) was analysed as a major compound in an aqueous solution after a biomass digestion process with Ba(OH)2. Gaseous and aqueous products after APR reaction of LA mixture with barium hydroxide were identified by different analytical techniques. Gaseous products consisted mainly of permanent gases such as hydrogen, carbon dioxide and methane. The results showed that mixture of LA in combination with both barium hydroxide and Pt/ZrO2 catalyst had the highest hydrogen production rate and the highest selectivity to hydrogen, whereas low gaseous product amount were observed from mixture of LA and only barium hydroxide or Pt/ZrO2 catalyst. Methane and higher amount of carbon dioxide were detected in gas phase products particular in the presence of Pt/ZrO2 catalyst in the mixture. Aqueous products consisted mainly of pyruvic acid, acetic acid and salts, such as acetate and propionate. The complete conversion of LA after APR was reached in mixture of LA and Ba(OH)2∙8H2O over Pt/ZrO2 catalyst. Mixture of LA and Ba(OH)2∙8H2O or Pt/ZrO2 catalyst gave lower conversion of LA. Amount of gaseous products, selectivity to hydrogen and LA conversion were affected by higher reactant mixture concentration. In comparison to low concentrated mixtures, high concentrated mixtures contained larger amounts of barium but the same amount of Pt/ZrO2 catalyst. BET analyses showed much smaller pore volume of spent Pt/ZrO2 catalyst, which was used in APR reaction of high concentrated (1.5 mol/L) mixture. Therefore, lower gas product amounts, lower selectivity to hydrogen and only 63 % conversion of LA were effects of deactivated Pt/ZrO2 catalyst. The results showed that hydrogen generation from APR of LA and conversion of LA in aqueous phase are hardly influenced by the Pt/ZrO2 catalyst presence, which in combination with barium ions, promotes the catalytic APR reaction.
Ključne besede: biomass, hydrogen production, aqueous phase reforming, lactic acid
Objavljeno: 20.02.2015; Ogledov: 1403; Prenosov: 125
.pdf Celotno besedilo (2,85 MB)

8.
9.
Reactive dye decolorization using combined ultrasound/H2O2
Darinka Brodnjak-Vončina, Alenka Majcen Le Marechal, 2003, izvirni znanstveni članek

Opis: The decolorization of six vinylsulphone reactive dyes (C.I. Reactive Yellow 15, C.I. Reactive Red 22, C.I. Reactive Blue 28, Remazol Dark Black N 150%, C.I. Reactive Blue 220 and C.I. Reactive Black 5) in aqueous solution was investigated using ultrasound and ultrasoundž hydrogen peroxide degradation. Two different concentration levels of hydrogen peroxide were used. The efficiency of the decolorization was evaluated by measuring the absorbance of the dye solutions. The results show that ultrasound treatment was significantly enhanced in the presence of H2O2.
Ključne besede: ultrasonic irradiation, decolorization, oxidation processes, hydrogen peroxide, reactive dyes, vinylsulphone reactive dyes
Objavljeno: 01.06.2012; Ogledov: 1456; Prenosov: 72
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10.
Comparison of H2O2/UV, H2O2/O3 and H2O2/Fe2+ processes for the decolorisation of vinylsulphone reactive dyes
Tanja Kurbus, Alenka Majcen Le Marechal, Darinka Brodnjak-Vončina, 2003, izvirni znanstveni članek

Opis: Six vinylsulphone reactive dyes were decolorised using three oxidation processes (H2O2/UV, H2O2/O3 and H2O2/Fe2+). The efficiency of decolorisation was measured by decolorisation time, absorbance, COD and TOC and the three methods of decolorisation are compared.
Ključne besede: textile reactive dyes, vinylsulphone dyes, decolorisation, hydrogen peroxide, UV irradiation, ozone, Fenton's reagent, pollution parameters, experimental design
Objavljeno: 01.06.2012; Ogledov: 1513; Prenosov: 88
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