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1.
Copper sulfate elicitation effect on biomass production, phenolic compounds accumulation, and antioxidant activity of Morus nigra L. stem node culture
Jan Senekovič, Špela Jelen, Andreja Urbanek Krajnc, 2025, izvirni znanstveni članek

Opis: Phenolic compounds are strong antioxidant and antibacterial agents with great pharmacological, medicinal, nutritional, and industrial value. The potential of Morus nigra in stem node culture was investigated for the production of phenolic compounds and their elicitation with CuSO4. Individual phenolic compounds in the samples were identified and quantified by using HPLC-PDA and HPLC-MS methods, while the content of total phenolic compounds, the content of total flavonoids, and the antioxidant activity of methanolic extracts were evaluated spectrophotometrically. The highest fresh and dry weights were obtained in plantlets treated with 0.5 mM CuSO4 for 42 days. The highest total phenolic content, total flavonoid content, and antioxidant activity of the extracts were determined in stem node cultures treated with 3 mM CuSO4 for 42 days. Under the latter conditions, the predominant representatives of the caffeoylquinic acids, p-coumaric acid derivatives, kaempferol derivatives, and quercetin derivatives also achieved the highest content. The most abundant phenolic compound in all samples was the chlorogenic acid. The nodal culture of M. nigra elicited with CuSO4 could potentially be used for the industrial production of phenolic compounds, especially caffeoylquinic acids. Moreover, considering the biochemical response to CuSO4 treatment and the ability to tolerate and accumulate copper, the potential application of M. nigra in phytoremediation is also highlighted.
Ključne besede: antioxidative potential, black mulberry, copper stress, elicitation of phenolics, flavonoids, in vitro culture, nodal culture, phenolic acids
Objavljeno v DKUM: 25.03.2025; Ogledov: 0; Prenosov: 10
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Integrated optimization framework for a biomass supply network and steam Rankine cycle
Monika Dokl, Zdravko Kravanja, Lidija Čuček, 2024, izvirni znanstveni članek

Opis: The optimization of biomass supply chains is becoming increasingly important, especially for low-density biomass feedstocks that have limited market value and require efficient handling and logistics. This study addresses this issue by proposing an integrated approach to optimize biomass supply chain networks for energy production with the steam Rankine cycle. The approach takes into account the inherent variability of feedstock availability and energy market values, to ensure adaptability to fluctuating conditions. The biomass supply network is formulated as a mixed-integer nonlinear programming problem, where the optimization objective is to maximize the economic viability of the system. The optimal configuration of the supply network includes the selection of biomass supply zones and storage facilities, the transportation links, and the optimization of the process variables within the conversion plants, taking into account the variable heat demand. The optimization approach is applied to a hypothetical case study of a relatively small region in Slovenia. The results show the economic viability of biomass utilization with a net present value of almost 300 MEUR, generating about 4 MW of electricity and 65 MW of heat. The uncertainties of the biomass supply, the fluctuations in product prices and the spatial scope of the case study are evaluated in addition. This analysis highlights and discusses the impact of these factors on the economic performance of the biomass supply chain network.
Ključne besede: copper(II) coordination compounds, methylamines, crystal structure, magnetic properties, thermogravimetric analysis
Objavljeno v DKUM: 31.01.2025; Ogledov: 0; Prenosov: 4
.pdf Celotno besedilo (1,15 MB)

4.
Time and potential-resolved comparison of copper disc and copper nanoparticles for electrocatalytic hydrogenation of furfural
Nik Maselj, Vasko Jovanovski, Francisco Ruiz-Zepeda, Matjaž Finšgar, Tamara Klemenčič, Jan Trputec, Ana Rebeka Kamšek, Marjan Bele, Nejc Hodnik, Primož Jovanovič, 2023, izvirni znanstveni članek

Opis: Herein, a comparative analysis of two case example catalysts for electrocatalytic hydrogenation (ECH) of furfural under acidic conditions, namely a copper polycrystalline disc and copper nanoparticles dispersed on carbon support, is performed. To gain a detailed insight on ECH trends, a task-specific methodology is employed based on electrochemistry–mass spectrometry coupling, which enabled time- and potential-resolved detection of volatile ECH products, i.e., 2-methylfurane (2-MF) and H2. In this way, the ability to elucidate potential-dependent product distribution for the two catalysts, namely faradaic efficiency, is achieved. Accordingly, the nanoparticulate analog is significantly more active toward competitive hydrogen evolution reaction and 2-MF production, whereas the polycrystalline sample is more selective toward furfuryl alcohol. The observed differences in ECH are ascribed to alterations in surface domains, which is supported by surface-sensitive lead underpotential deposition characterization.
Ključne besede: baker, nanodelci, elektrokataliza, copper, nanoparticles, electrocatalytic hydrogeneration
Objavljeno v DKUM: 19.04.2024; Ogledov: 161; Prenosov: 11
.pdf Celotno besedilo (3,22 MB)
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Patterns of Copper Bioaccumulation and Translocation in Grapevine Grafts Depending on Rootstocks
Stanko Vršič, Mojca Gumzej, MARIO LEŠNIK, Andrej Perko, Borut Pulko, 2023, izvirni znanstveni članek

Opis: The long-term use of copper (Cu) fungicides in viticulture in Europe has led to Cu accumulation in vineyard top soils. However, less is known about the accumulation of Cu in grapevine grafts after the callusing process/before planting in the nursery. This paper presents the capacity of 5BB and SO4 rootstocks to accumulate Cu, as well as the patterns of translocation in the grafts. After heat forcing (callusing), the grapevine grafts of Sauvignon Blanc on 5BB and SO4 rootstocks were grown in pots for six months in a glasshouse and exposed to various Cu formulations (Cu-oxychloride, Cu-gluconate) and concentrations in peat (50, 150, 500, and 1000 mg Cu of dry weight (DW)). In addition to monitoring the shoot growth dynamics and analyzing the copper content in graft organs, bioaccumulation (BAFs) and translocation factors (TFs) of Cu were calculated. The mean Cu concentrations were ranked as follows: roots (15–164) > rootstock trunks (8–38) > canes (5–21) mg kg−1 DW. The Cu concentrations depended on the Cu formulation and concentration in the substrate. Higher Cu content was found in the roots of both rootstocks (5BB and SO4, 23–155 and 15–164 mg kg−1 DW, respectively) and the lowest in the canes (less than 10 mg kg−1 DW) of grafts grown in Cu-oxychloride-treated peat. Based on the BAFs and TFs, both rootstocks could be considered as Cu exclusive. A higher translocation rate was determined in systemic Cu-gluconate and SO4 rootstock. With shoot length measurements, the significant inhibitory effects of Cu on grapevine grafts growth could not be confirmed, despite the inhibitory effects that were clearly expressed in the first two months of growth. Soils containing more than 500 mg Cu/kg−1 are less suitable for growing vine grafts.
Ključne besede: grapevine grafts, copper accumulation, Cu-oxychloride, Cu-gluconate, 5BB and SO4 rootstocks
Objavljeno v DKUM: 08.12.2023; Ogledov: 457; Prenosov: 30
.pdf Celotno besedilo (1,40 MB)
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7.
Electrochemical and surface analysis of 2-phenylimidazole adsorbed on copper from chloride solution
Matjaž Finšgar, Klodian Xhanari, 2018, izvirni znanstveni članek

Opis: The electroanalytical and surface characterization of copper immersed in 3 wt.% NaCl solution containing 1 mM of 2-phenylimidazole (2PhI) is presented. It was proven that 2PhI can be employed as corrosion inhibitor for copper using various electrochemical analyses, such as cyclic voltammetry, chronopotentiometry, electrochemical impedance spectroscopy, and potentiodynamic curve measurements. The adsorption of 2PhI on copper was further analyzed by 3D-profilometry, attenuated total reflectance Fourier transform infrared spectroscopy, contact angle measurements, and scanning electron microscopy equipped with an energy dispersive X-ray spectrometer. This system was therefore comprehensively described by various analytical approaches.
Ključne besede: corrosion inhibitor, copper, electrochemical impedance spectroscopy, EIS, cyclic voltammetry, attenuated total reflectance Fourier transform infrared, ATR-FTIR
Objavljeno v DKUM: 17.01.2019; Ogledov: 2084; Prenosov: 397
.pdf Celotno besedilo (5,88 MB)
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8.
Synthesis and characterization of hardened Cu-Fe-Ni-P alloy
Goran Brovč, Goran Dražić, Blaž Karpe, Igor Đorđević, Gorazd Lojen, Borut Kosec, Milan Bizjak, 2015, izvirni znanstveni članek

Opis: In the manufacturing industry of electrical contacts, the prohibition of the use of toxic metals (Cd, Be), and desire to avoid the alloying with precious metals (Ag) has created a need for new alloys with good electrical conductivity and high mechanical properties at elevated temperatures. As a potentially useful material for this purpose, we have analyzed the continuously cast Cu-Fe-Ni-P alloy in various heat treatment conditions. Sequence of phase transformations during heat treatment was followed by 4 point D.C. electrical resistivity measuring method, and analyzed by scanning (SEM) and transmission (TEM) electron microscopy. Measurements of Vickers hardness and electrical conductivity after various heat treatment procedures indicate on high potential of Cu-Fe-Ni-P alloys as a material for electrical contacts.
Ključne besede: copper alloys, precipitation hardening, electrical contacts, electrical conductivity
Objavljeno v DKUM: 03.07.2017; Ogledov: 2320; Prenosov: 97
.pdf Celotno besedilo (454,32 KB)
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Analysis of a strain rate field in cold formed material using the visioplasticity method
Leo Gusel, Rebeka Rudolf, Borut Kosec, 2009, drugi znanstveni članki

Opis: In this paper the visioplasticity method is used to find the complete velocity and strain rate distributions from the experimental data, using the finite-difference method. The data about values of strain rates in plastic re- gion of the material is very important for calculating stresses and the prediction of product quality. Specimens of copper alloy were extruded with different lubricants and different coefficients of friction and then the strain rate distributions were analysed and compared. Significant differences in velocity and strain rate distributions were obtained in some regions at the exit of the deformed zone.
Ključne besede: forward extrusion, copper alloy, visioplasticity, strain rate, lubrication
Objavljeno v DKUM: 03.07.2017; Ogledov: 966; Prenosov: 145
.pdf Celotno besedilo (733,12 KB)
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