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1.
COST AND ENERGY EFFICIENT MODERNIZATION OF SCHOOL BUILDINGS IN UKRAINE
Tetiana Rapina, Marjana Šijanec Zavrl, Henrik Gjerkeš, 2016, kratki znanstveni prispevek

Opis: Improvement of the energy efficiency of existing buildings in EU has great potential in the efforts to reduce energy consumption, which is with no doubt relevant issue also for Ukraine. In this article the importance of public building stock modernization was analysed with special focus on school buildings. The optimal cost methodology was used to evaluate not only the economic, but also environmental as well as social effects of school building stock modernization. In searching for the optimal level of energy-efficient modernization of school buildings in Ukraine, the European and Slovenian experiences were used. It is demonstrated that the sustainable reconstruction with the nearly-Zero Energy Building (nZEB) guidelines, as defined in EU regulations, is feasible with good results and can be recommended also for reconstruction of school buildings in Ukraine.
Najdeno v: ključnih besedah
Povzetek najdenega: ...Improvement of the energy efficiency of existing buildings in EU has great...
Ključne besede: cost optimum, energy efficiency, nearly zero energy building, building envelope, heating
Objavljeno: 15.04.2016; Ogledov: 4599; Prenosov: 0
.pdf Polno besedilo (474,44 KB)

2.
Substantial brown carbon emissions from wintertime residential wood burning over France
Jean-Luc Jaffrezo, Valérie Gros, Griša Močnik, Gilles Levigoureux, Marta Dominik-Sègue, Eve Chrétien, Sabrina Pontet, Gregory Gille, Florie Chevrier, Véronique Jacob, Jean-Eudes Petit, Alexandre Albinet, Yunjiang Zhang, Olivier Favez, 2020, izvirni znanstveni članek

Opis: Brown carbon (BrC) is known to absorb light at subvisible wavelengths but its optical properties and sources are still poorly documented, leading to large uncertainties in climate studies. Here, we show its major wintertime contribution to total aerosol absorption at 370 nm (18–42%) at 9 different French sites. Moreover, an excellent correlation with levoglucosan (r2 = 0.9 and slope = 22.2 at 370 nm), suggesting important contribution of wood burning emissions to ambient BrC aerosols in France. At all sites, BrC peaks were mainly observed during late evening, linking to local intense residential wood burning during this time period. Furthermore, the geographic origin analysis also highlighted the high potential contribution of local and/or small-regional emissions to BrC. Focusing on the Paris region, twice higher BrC mass absorption efficiency value was obtained for less oxidized biomass burning organic aerosols (BBOA) compared to more oxidized BBOA (e.g., about 4.9 ± 0.2 vs. 2.0 ± 0.1 m2 g−1, respectively, at 370 nm). Finally, the BBOA direct radiative effect was found to be 40% higher when these two BBOA fractions are treated as light-absorbing species, compared to the non-absorbing BBOA scenario.
Najdeno v: ključnih besedah
Povzetek najdenega: ...Paris region, twice higher BrC mass absorption efficiency value was obtained for less oxidized biomass...
Ključne besede: Brown carbon, Multi sites, Residential wood burning, Mass absorption efficiency, France
Objavljeno: 20.07.2020; Ogledov: 2193; Prenosov: 0
.pdf Polno besedilo (2,94 MB)

3.
Temperature-controlled airflow ventilation in operating rooms compared with laminar airflow and turbulent mixed airflow
Malin Alsved, A. Civilis, P. Ekolind, Tina Šantl Temkiv, Jakob Löndahl, 2017, izvirni znanstveni članek

Najdeno v: ključnih besedah
Povzetek najdenega: ...Surgical site infection, BioTrak, Fluorescence, Energy efficiency, Temperature-controlled ventilation, Air sampling...
Ključne besede: Surgical site infection, BioTrak, Fluorescence, Energy efficiency, Temperature-controlled ventilation, Air sampling
Objavljeno: 04.01.2021; Ogledov: 1635; Prenosov: 0
.pdf Polno besedilo (1,99 MB)

4.
A pyrrolopyridazinedione-based copolymer for fullerene-free organic solar cells
Astrid-Caroline Knall, Samuel Rabensteiner, Sebastian F. Hoefler, Matiss Reinfelds, Mathias Hobisch, Heike M. A. Ehmann, Nadiia Pastukhova, Egon Pavlica, Gvido Bratina, Illie Hanzu, Shuguang Wen, Renqiang Yang, Gregor Trimmel, Thomas Rath, 2021, izvirni znanstveni članek

Opis: The recent success of non-fullerene acceptors in organic photovoltaics also entails a change in the requirements to the polymer donor in terms of optical and morphological properties leading to a demand for novel conjugated polymers. Herein, we report on the synthesis of a 1,4-bis-(thiophene-2-yl)-pyrrolopyridazinedione based copolymer with 2-ethylhexyl substituents on the pyrrolopyridazinedione moiety. A 2D conjugated benzodithiophene (BDT) was chosen as comonomer. The resulting copolymer T-EHPPD-T-EHBDT showed a molecular weight of 10.2 kDa, an optical band gap of 1.79 eV, a hole mobility of 1.8 × 10−4 cm2 V−1 s−1 and a preferred face-on orientation with regard to the substrate. The comparably wide band gap as well as the determined energy levels (HOMO: −5.47 eV, LUMO: −3.68 eV) match well with the narrow band gap non-fullerene acceptor ITIC-F, which was used as the acceptor phase in the bulk heterojunction absorber layers in the investigated solar cells. The solar cells, prepared in inverted architecture, revealed power conversion efficiencies up to 7.4% using a donor:acceptor ratio of 1 : 1 in the absorber layer.
Najdeno v: ključnih besedah
Ključne besede: non-fullerene solar cells, charge transport, charge mobility, power conversion efficiency
Objavljeno: 27.01.2021; Ogledov: 1793; Prenosov: 0
.pdf Polno besedilo (2,68 MB)

5.
Electrolysis energy efficiency of highly concentrated FeCl[sub]2 solutions for power-to-solid energy storage technology
Matjaž Valant, Uroš Luin, 2022, izvirni znanstveni članek

Opis: An electrochemical cycle for the grid energy storage in the redox potential of Fe involves the electrolysis of a highly concentrated aqueous FeCl2 solution yielding solid iron deposits. For the high overall energy efficiency of the cycle, it is crucial to maximize the energy efficiency of the electrolysis process. Here we present a study of the influence of electrolysis parameters on the energy efficiency of such electrolysis, performed in an industrial-type electrolyzer. We studied the conductivity of the FeCl2 solution as a function of concentration and temperature and correlated it with the electrolysis energy efficiency. The deviation from the correlation indicated an important contribution from the conductivity of the ion-exchange membrane. Another important studied parameter was the applied current density. We quantitatively showed how the contribution of the resistance polarization increases with the current density, causing a decrease in overall energy efficiency. The highest energy efficiency of 89 ± 3% was achieved using 2.5 mol L−1 FeCl2 solution at 70 °C and a current density of 0.1 kA m−2. In terms of the energy input per Fe mass, this means 1.88 Wh g−1. The limiting energy input per mass of the Fe deposit was found to be 1.76 Wh g−1.
Najdeno v: ključnih besedah
Ključne besede: electrolysis, ferrous chloride, iron deposition, energy efficiency
Objavljeno: 16.02.2022; Ogledov: 944; Prenosov: 67 
(1 glas)
.pdf Polno besedilo (1,99 MB)
Gradivo ima več datotek! Več...

6.
Fractal and spectroscopic analysis of soot from internal combustion engines
Sankararaman S, RAJ VIMAL, SARITHA DEVI H V, Swapna Mohanachandran Nair Sindhu, 2018, izvirni znanstveni članek

Opis: Today diesel engines are used worldwide for various applications and very importantly in transportation. Hydrocarbons are the most widespread precursors among carbon sources employed in the production of carbon nanotubes (CNTs). The aging of internal combustion engine is an important parameter in deciding the carbon emission and particulate matter due to incomplete combustion of fuel. In the present work, an attempt has been made for the effective utilization of the aged engines for potential applicationapplications in fuel cells and nanoelectronics. To analyze the impact of aging, the particulate matter rich in carbon content areis collected from diesel engines of different ages. The soot with CNTs is purified by the liquid phase oxidation method and analyzed by Field Emission Scanning Electron Microscopy, High-Resolution Transmission Electron Microscopy, Energy Dispersive Spectroscopy, UV-Visible spectroscopy, Raman spectroscopy and Thermogravimetric analysis. The SEM image contains self-similar patterns probing fractal analysis. The fractal dimensions of the samples are determined by the box counting method. We could find a greater amount of single-walled carbon nanotubes (SWCNTs) in the particulate matter emitted by aged diesel engines and thereby giving information about the combustion efficiency of the engine. The SWCNT rich sample finds a wide range of applications in nanoelectronics and thereby pointing a potential use of these aged engines.
Najdeno v: ključnih besedah
Povzetek najdenega: ...and thereby giving information about the combustion efficiency of the engine. The SWCNT rich sample...
Ključne besede: Fractals, internal combustion engine, efficiency, soot, carbon nanoparticle
Objavljeno: 30.06.2022; Ogledov: 496; Prenosov: 0
.pdf Polno besedilo (1,05 MB)

7.
Development of Zinc Oxide-Multi-Walled Carbon Nanotube hybrid nanofluid for energy-efficient heat transfer application: A thermal lens study
Swapna Mohanachandran Nair Sindhu, 2021, izvirni znanstveni članek

Opis: This paper addresses the need for developing an energy-efficient hybrid nanofluid with zinc oxide–multi-walled carbon nanotube (ZnO-MWCNT) for overcoming the bottleneck of efficient heat transfer in thermal systems. The concentration-dependent thermal diffusivity modifications are analyzed using the highly sensitive mode mismatched thermal lens technique. The hybrid composite is prepared by the solid-state mixing and annealing of a pure multi-walled carbon nanotube (MWCNT) and zinc oxide (ZnO), synthesized by the solution combustion method. The composite formation is studied by structural, morphological, and optical characterization techniques. Among the three nanofluids ZnO, MWCNT, and ZnO-MWCNT, the composite exhibits a drastic enhancement in thermal diffusivity at a lower solid volume fraction of 0.047 mg/ml containing 0.009 mg/ml of MWCNT. All the nanofluids show an optimum concentration beyond which the thermal diffusivity decreases with the nanoparticle concentration. Thus, this study suggests the potential application of ZnO-MWCNT hybrid nanofluids in thermal system design to enhance internal combustion engines' efficiency during cold-start.
Najdeno v: ključnih besedah
Povzetek najdenega: ...system design to enhance internal combustion engines' efficiency during cold-start....
Ključne besede: Zinc Oxide, MWCNT, hybrid nanofluid, thermal lens, diffusivity, engine efficiency
Objavljeno: 30.06.2022; Ogledov: 493; Prenosov: 0
.pdf Polno besedilo (2,44 MB)

8.
Efficiency of the grid energy storage technology based on iron-chloride material cycle
Uroš Luin, doktorska disertacija

Opis: Future high-capacity energy storage technologies are crucial for a highly renewable energy mix, and their mass deployment must rely on cheap and abundant materials, such as iron chloride. The iron chloride electrochemical cycle (ICEC), suitable for long-term grid energy storage using a redox potential change of Fe2+/Fe, involves the electrolysis of a highly concentrated aqueous FeCl2 solution yielding solid iron deposits. For the high overall energy efficiency of the cycle, it is crucial maximizing the energy efficiency of the electrolysis process. The thesis presents a study of the influence of electrolysis parameters on energy efficiency, performed in an industrial-type electrolyzer system. We studied the conductivity of the FeCl2 solution as a function of concentration and temperature and correlated it with the electrolysis energy efficiency as a function of current density. The contribution of the resistance polarization increases with the current density, causing a decrease in overall energy efficiency. The highest energy efficiency of 89 ±3 % was achieved using 2.5 mol dm-3 FeCl2 solution at 70 °C and a current density of 0.1 kA m-2. In terms of the energy input per Fe mass, this means 1.88 Wh g-1. The limiting energy input per mass of the Fe-deposit, calculated by extrapolating experimental results toward Eocell potential, was found to be 1.76 Wh g-1. For optimal long-duration electrolysis efficiency and performance, the optimal catholyte concentration range is 1-2 mol dm-3 FeCl2. We performed in situ X-ray absorption spectroscopy experimental studies to validate theoretical conclusions from literature related to the population and structure of Fe-species in the FeCl2 (aq) solution at different concentrations (1 - 4 mol dm-3) and temperatures (25 - 80 °C). This revealed that at low temperature and low FeCl2 concentration, the octahedral first coordination sphere around Fe is occupied by one Cl ion at a distance of 2.33 (±0.02) Å and five H2O at a distance of 2.095 (±0.005) Å. The structure of the ionic complex gradually changes with an increase in temperature and/or concentration. The apical H2O is substituted by a Cl ion to yield a neutral Fe[Cl2(H2O)4]0. The transition from the charged Fe[Cl(H2O)5]+ to the neutral Fe[Cl2(H2O)4]0 causes a significant drop in the solution conductivity, which well correlates with the existing state-of-the-art conductivity models. An additional steric impediment of the electrolytic cell is caused by the predominant neutral species present in the catholyte solution at high concentration. This correlates with poor electrolysis performance at a very high catholyte concentration (4 mol dm-3 FeCl2), especially at high current densities (> 1 kA m-2). The neutral Fe[Cl2(H2O)4]0 complex negatively affects the anion exchange membrane ion (Cl-) transfer and lowers the concentration of electroactive species (Fe[Cl(H2O)5]+) at the cathode surface. The kinetics of hydrogen evolution from the reaction between Fe powder and HCl acid was studied under the first-order reaction condition. The activation energy was determined to be 55.3 kJ mol-1.
Najdeno v: ključnih besedah
Ključne besede: ICEC, Power-to-Solid, energy storage, hydrogen, ferrous chloride, electrolysis, Fe deposition, efficiency, XAS, structure and population, ionic species, ion association, conductivity
Objavljeno: 18.04.2023; Ogledov: 181; Prenosov: 12 
(1 glas)
.pdf Polno besedilo (4,34 MB)

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