Browsing by Subject "ENERGY"

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  • Andrienko, Gennady; Andrienko, Natalia; Boldrini, Chiara; Caldarelli, Guido; Cintia, Paolo; Cresci, Stefano; Facchini, Angelo; Giannotti, Fosca; Gionis, Aristides; Guidotti, Riccardo; Mathioudakis, Michael; Muntean, Cristina Ioana; Pappalardo, Luca; Pedreschi, Dino; Pournaras, Evangelos; Pratesi, Francesca; Tesconi, Maurizio; Trasarti, Roberto (2021)
    The exponential increase in the availability of large-scale mobility data has fueled the vision of smart cities that will transform our lives. The truth is that we have just scratched the surface of the research challenges that should be tackled in order to make this vision a reality. Consequently, there is an increasing interest among different research communities (ranging from civil engineering to computer science) and industrial stakeholders in building knowledge discovery pipelines over such data sources. At the same time, this widespread data availability also raises privacy issues that must be considered by both industrial and academic stakeholders. In this paper, we provide a wide perspective on the role that big data have in reshaping cities. The paper covers the main aspects of urban data analytics, focusing on privacy issues, algorithms, applications and services, and geo-referenced data from social media. In discussing these aspects, we leverage, as concrete examples and case studies of urban data science tools, the results obtained in the "City of Citizens" thematic area of the Horizon 2020 SoBigData initiative, which includes a virtual research environment with mobility datasets and urban analytics methods developed by several institutions around Europe. We conclude the paper outlining the main research challenges that urban data science has yet to address in order to help make the smart city vision a reality.
  • Härkönen, S.; Neumann, M.; Mues, V.; Berninger, F.; Bronisz, K.; Cardellini, G.; Chirici, G.; Hasenauer, H.; Koehl, M.; Lang, M.; Merganicova, K.; Mohren, F.; Moiseyev, A.; Moreno, A.; Mura, M.; Muys, B.; Olschofsky, K.; Del Perugia, B.; Rorstad, P. K.; Solberg, B.; Thivolle-Cazat, A.; Trotsiuk, V.; Mäkelä, A. (2019)
    FORMIT-M is a widely applicable, open-access, simple and flexible, climate-sensitive forest management simulator requiring only standard forest inventory data as input. It combines a process-based carbon balance approach with a strong inventory-based empirical component. The model has been linked to the global forest sector model EFI-GTM to secure consistency between timber cutting and demand, although prescribed harvest scenarios can also be used. Here we introduce the structure of the model and demonstrate its use with example simulations until the end of the 21st century in Europe, comparing different management scenarios in different regions under climate change. The model was consistent with country-level statistics of growing stock volumes (R-2=0.938) and its projections of climate impact on growth agreed with other studies. The management changes had a greater impact on growing stocks, harvest potential and carbon balance than projected climate change, at least in the absence of increased disturbance rates.
  • Iwaniec, Tadeusz; Onninen, Jani; Pankka, Pekka; Radice, Teresa (2021)
    This article is about hyperelastic deformations of plates (planar domains) which minimize a neohookean-type energy. Particularly, we investigate a stored energy functional introduced by J. M. Ball [Proc. Roy. Soc. Edinb. Sect. A, 88 (1981), pp. 315-328]. The mappings under consideration are Sobolev homeomorphisms and their weak limits. They are monotone in the sense of C. B. Morrey. One major advantage of adopting monotone Sobolev mappings lies in the existence of the energy-minimal deformations. However, injectivity is inevitably lost, so an obvious question to ask is, what are the largest subsets of the reference configuration on which minimal deformations remain injective? The fact that such subsets have full measure should be compared with the notion of global invertibility, which deals with subsets of the deformed configuration instead. In this connection we present a Cantor-type construction to show that both the branch set and its image may have positive area. Another novelty of our approach lies in allowing the elastic deformations to be free along the boundary, known as frictionless problems.
  • Baer, Robin M.; Kirschner, Stefan; Nieger, Martin; Bräse, Stefan (2018)
    Herein the addition of different thiols to the strained carbon-carbon bond of [1.1.1]propellane (1) is reported. The reaction pathway was investigated, addition reactions with substituted thiols, hydrogen sulfide and protected cysteine were performed, and further modifications of the products were verified. The clean reaction proceeds by a radical chain process, which was confirmed by different deuterium labelling experiments. It shows high functional-group tolerance, since halo-, hydroxy-, methoxy-, carboxy-, amino- and nitro-substituted thiols could be added to 1 with few by-products in 16-90% yield. Oxidation of the products allows tuning of the polarity and subsequent reactions of the products. The click-type reaction proceeds even faster with selenols, as was shown in a proof of concept. Thiol addition to 1 offers a facile tool for surface modification, conjugation and tuning of hydrophilicity in bio- and medicinal chemistry.
  • Järviö, Natasha; Maljanen, Netta-Leena; Kobayashi, Yumi; Ryynänen, Toni; Tuomisto, Hanna (2021)
    Novel food production technologies are being developed to address the challenges of securing sustainable and healthy nutrition for the growing global population. This study assessed the environmental impacts of microbial protein (MP) produced by autotrophic hydrogen-oxidizing bacteria (HOB). Data was collected from a company currently producing MP using HOB (hereafter simply referred to as MP) on a small-scale. Earlier studies have performed an environmental assessment of MP on a theoretical basis but no study yet has used empirical data. An attributional life cycle assessment (LCA) with a cradle-to-gate approach was used to quantify global warming potential (GWP), land use, freshwater and marine eutrophication potential, water scarcity, human (non-)carcinogenic toxicity, and the cumulative energy demand (CED) of MP production in Finland. A Monte Carlo analysis was performed to assess uncertainties. The impacts of alternative production options and locations were explored. The impacts were compared with animal- and plant-based protein sources for human consumption as well as protein sources for feed. The results showed that electricity consumption had the highest contribution to environmental impacts. Therefore, the source of energy had a substantial impact on the results. MP production using hydropower as an energy source yielded 87.5% lower GWP compared to using the average Finnish electricity mix. In comparison with animal-based protein sources for food production, MP had 53-100% lower environmental impacts depending on the reference product and the source of energy assumed for MP production. When compared with plant-based protein sources for food production, MP had lower land and water use requirements, and eutrophication potential but GWP was reduced only if low-emission energy sources were used. Compared to protein sources for feed production, MP production often resulted in lower environmental impact for GWP (FHE), land use, and eutrophication and acidification potential, but generally caused high water scarcity and required more energy.
  • Joshi, Satya P.; Pekkanen, Timo T.; Seal, Prasenjit; Timonen, Raimo S.; Eskola, Arkke J. (2021)
    The kinetics of the reaction between resonance-stabilized (CH3)(2)CCHCH2 radical (R) and O-2 has been investigated using photoionization mass spectrometry, and master equation (ME) simulations were performed to support the experimental results. The kinetic measurements of the (CH3)(2)CCHCH2 + O-2 reaction (1) were carried out at low helium bath-gas pressures (0.2-5.7 Torr) and over a wide temperature range (238-660 K). Under low temperature (238-298 K) conditions, the pressure-dependent bimolecular association reaction R + O-2 -> ROO determines kinetics, until at an intermediate temperature range (325-373 K) the ROO adduct becomes thermally unstable and increasingly dissociates back to the reactants with increasing temperature. The initial association of O-2 with (CH3)(2)CCHCH2 radical occurs on two distinct sites: terminal 1(t) and non-terminal 1(nt) sites on R, leading to the barrierless formation of ROO(t) and ROO(nt) adducts, respectively. Important for autoignition modelling of olefinic compounds, bimolecular reaction channels appear to open for the R + O-2 reaction at high temperatures (T > 500 K) and pressure-independent bimolecular rate coefficients of reaction (1) with a weak positive temperature dependence, (2.8-4.6) x 10(-15) cm(3) molecule(-1) s(-1), were measured in the temperature range of 500-660 K. At a temperature of 501 K, a product signal of reaction (1) was observed at m/z = 68, probably originating from isoprene. To explore the reaction mechanism of reaction (1), quantum chemical calculations and ME simulations were performed. According to the ME simulations, without any adjustment to energies, the most important and second most important product channels at the high temperatures are isoprene + HO2 (yield > 91%) and (2R/S)-3-methyl-1,2-epoxybut-3-ene + OH (yield < 8%). After modest adjustments to ROO(t) and ROO(nt) well-depths (similar to 0.7 kcal mol(-1) each) and barrier height for the transition state associated with the kinetically most dominant channel, R + O-2 -> isoprene + HO2 (similar to 2.2 kcal mol(-1)), the ME model was able to reproduce the experimental findings. Modified Arrhenius expressions for the kinetically important reaction channels are enclosed to facilitate the use of current results in combustion models.
  • Sundholm, Dage; Berger, Raphael J. F.; Fliegl, Heike (2016)
    Magnetically induced current susceptibilities and current pathways have been calculated for molecules consisting of two pentalene groups annelated with a benzene (1) or naphthalene (2) moiety. Current strength susceptibilities have been obtained by numerically integrating separately the diatropic and paratropic contributions to the current flow passing planes through chosen bonds of the molecules. The current density calculations provide novel and unambiguous current pathways for the unusual molecules with annelated aromatic and antiaromatic hydrocarbon moieties. The calculations show that the benzene and naphthalene moieties annelated with two pentalene units as in molecules 1 and 2, respectively, are unexpectedly antiaromatic sustaining only a local paratropic ring current around the ring, whereas a weak diatropic current flows around the C-H moiety of the benzene ring. For 1 and 2, the individual five-membered rings of the pentalenes are antiaromatic and a slightly weaker semilocal paratropic current flows around the two pentalene rings. Molecules 1 and 2 do not sustain any net global ring current. The naphthalene moiety of the molecule consisting of a naphthalene annelated with two pentalene units (3) does not sustain any strong ring current that is typical for naphthalene. Instead, half of the diatropic current passing the naphthalene moiety forms a zig-zag pattern along the C-C bonds of the naphthalene moiety that are not shared with the pentalene moieties and one third of the current continues around the whole molecule partially cancelling the very strong paratropic semilocal ring current of the pentalenes. For molecule 3, the pentalene moieties and the individual five-membered rings of the pentalenes are more antiaromatic than for 1 and 2. The calculated current patterns elucidate why the compounds with formally [4n + 2] p-electrons have unusual aromatic properties violating the Huckel pi-electron count rule. The current density calculations also provide valuable information for interpreting the measured H-1 NMR spectra.
  • Popov, Georgi; Mattinen, Miika Juhana; Hatanpää, Timo; Vehkamäki, Marko; Kemell, Marianna; Mizohata, Kenichiro; Räisänen, Jyrki; Ritala, Mikko; Leskelä, Markku (2019)
    Atomic layer deposition (ALD) enables the deposition of numerous materials in thin film form, yet there are no ALD processes for metal iodides. Herein, we demonstrate an ALD process for PbI2, a metal iodide with a two-dimensional (2D) structure that has applications in areas such as photo-detection and photovoltaics. This process uses lead silylamide Pb(btsa)(2) and SnI4 as precursors and works at temperatures below 90 degrees C, on a variety of starting surfaces and substrates such as polymers, metals, metal sulfides, and oxides. The starting surface defines the crystalline texture and morphology of the PbI2 films. Rough substrates yield porous PbI2 films with randomly oriented 2D layers, whereas smooth substrates yield dense films with 2D layers parallel to the substrate surface. Exposure to light increases conductivity of the ALD PbI2 films which enables their use in photodetectors. The films can be converted into a CH3NH3PbI3 halide perovskite, an important solar cell absorber material. For various applications, ALD offers advantages such as ability to uniformly coat large areas and simple means to control film thickness. We anticipate that the chemistry exploited in the PbI2 ALD process is also applicable for ALD of other metal halides.
  • Kaljonen, Minna; Peltola, Taru; Salo, Marja; Furman, Eeva (2019)
    The critical role of everyday practices in climate change mitigation has placed experimental approaches at the top of the environmental policy agenda. In this paper we discuss the value of behavioural approaches, practice theories, pragmatic tinkering and speculative thinking with respect to experimentation. Whereas the first two have been much discussed within sustainability science and transition research, the notions of pragmatic tinkering and speculative thinking radically broaden the scope of experimental research and its contribution to sustainable everyday practices. Pragmatism brings to the fore the need to coordinate multiple practices and understandings of good eating, as these may clash in practice. Through this lens, the value of experimental research lies in revealing frictions that need to be resolved, or tinkered, in practice. Speculative experimentation, in turn, refers to the power of experiments to challenge the experimental setting itself and force thinking about new possibilities and avenues. We investigate the value of all four approaches in relation to our experiments with sustainable eating in the Finnish and Nordic context. Our elaboration justifies the need to broaden the conception of experimental research in order to capture the multiplicity of sustainable eating. Hence, we call for attentive, speculative experimental research aimed not only at testing solutions for sustainable everyday practice, but also at reflecting on the practice of experimentation itself.
  • Jonsson, Ragnar; Rinaldi, Francesca; Pilli, Roberto; Fiorese, Giulia; Hurmekoski, Elias; Cazzaniga, Noemi; Robert, Nicolas; Camia, Andrea (2021)
    This study adds to the scientific literature dealing with the climate change mitigation implications of wood substitution. Its main scientific contribution rests with the modelling approach. By fully integrating forest resource and wood-product markets modelling in quantitative scenario analysis, we account for international trade in wood products as well as impacts on EU forests and forest-based sector employment of an increased EU uptake of wood-based construction and/or biochemicals and biofuels. Our results confirm the crucial role of the sawmilling industry in the forest-based bioeconomy. Thus, boosting wood-based construction in the EU would be most effective in increasing EU production and employment—in logging and solid wood-products manufacturing, but also in sectors using sawmilling byproducts as feedstock. Vertical integration in wood-based biorefineries should thus be advantageous. The positive EU climate-change mitigation effects of increased carbon storage in harvested wood products (HWP) and material substitution from increased wood construction are more than offset by reduced net forests carbon sinks by 2030, due to increased EU harvests. Further, increased EU imports, resulting in lower consumption of sawnwood outside the EU, would reduce extra-EU long-life HWP carbon storage and substitution of GHG-intensive materials, highlighting the need for concerted international climate change mitigation
  • Quiroz, Jhon; de Oliveira, Paulo F. M.; Shetty, Shwetha; Oropeza, Freddy E.; de la Pena O'Shea, Victor A.; Rodrigues, Lucas C.; Rodrigues, Maria P. de S.; Torresi, Roberto Manuel; Emmerling, Franziska; Camargo, Pedro H. C. (2021)
    The localized surface plasmon resonance (LSPR) excitation in plasmonic nanoparticles (NPs) in the visible and near-infrared ranges is currently at the forefront of improving photocatalytic performances via plasmonic photocatalysis. One bottleneck of this field is that the NPs that often display the best optical properties in the visible and near-infrared ranges are based on expensive noble metals such as silver (Ag) and gold (Au). While earth-abundant plasmonic materials have been proposed together with catalytic metals in antenna-reactor systems, their performances remain limited by their optical properties. Importantly, the synthesis of plasmonic photocatalysts remains challenging in terms of scalability while often requiring several steps, high temperatures, and special conditions. Herein, we address these challenges by developing a one-pot, gram-scale, room-temperature synthesis of earth-abundant plasmonic photocatalysts while improving their activities beyond what has been dictated by the LSPR excitation of the plasmonic component. We describe the mechanochemical synthesis of earth-abundant plasmonic photocatalysts by using MoO3 (antenna) and Au (reactor) NPs as a proof-of-concept example and demonstrate that the dual plasmonic excitation of antenna and reactor sites enables the tuning of plasmonic photocatalytic performances toward the reductive coupling of nitrobenzene to azobenzene as a model reaction. In addition to providing a pathway to the facile and gramscale synthesis of plasmonic photocatalysts, the results reported herein may open pathways to improved activities in plasmonic catalysis.
  • Chaichian, Masud; Kluson, Josef; Oksanen, Markku; Tureanu, Anca (2014)
  • Kröger, Björn (2018)
    Near-equatorial peak diversities are a prominent first-order feature of today's latitudinal diversity gradient (LDG), but were not a persistent pattern throughout geological time. In an analysis of Ordovician (485-444 Ma) fossil occurrences, an equatorward shift of the latitudinal diversity peak can be detected. A modern-type LDG and out-of-the-tropics range shift pattern were synchronously established during emerging icehouse conditions at the climax of the Great Ordovician Biodiversity Event. The changes in the LDG pattern and range shift trends can be best explained as a consequence of global cooling during the Middle Ordovician and of diversification in the tropical realm following a greenhouse period with temperatures too hot to support diverse tropical marine life. These results substantiate a fundamental role of temperature changes in establishing global first-order diversity patterns.
  • Abelev, B.; Adam, J.; Adamova, D.; Aggarwal, M. M.; Rinella, G. Aglieri; Agnello, M.; Agostinelli, A.; Agrawal, N.; Ahammed, Z.; Ahmad, N.; Ahmed, I.; Ahn, S. U.; Ahn, S. A.; Aimo, I.; Aiola, S.; Ajaz, M.; Akindinov, A.; Alam, S. N.; Aleksandrov, D.; Alessandro, B.; Alexandre, D.; Alici, A.; Alkin, A.; Alme, J.; Alt, T.; Altinpinar, S.; Altsybeev, I.; Garcia Prado, C. Alves; Andrei, C.; Andronic, A.; Anguelov, V.; Anielski, J.; Anticic, T.; Antinori, F.; Antonioli, P.; Aphecetche, L.; Appelshaeuser, H.; Arcelli, S.; Armesto, N.; Arnaldi, R.; Aronsson, T.; Arsene, I. C.; Chang, B.; Hilden, T. E.; Kim, D. J.; Kral, J.; Pohjoisaho, E. H. O.; Rak, J.; Rasanen, S. S.; Trzaska, W. H. (2015)
    The differential charged jet cross sections, jet fragmentation distributions, and jet shapes are measured in minimum bias proton-proton collisions at center-of-mass energy root s = 7 TeV using the ALICE detector at the LHC. Jets are reconstructed from charged particle momenta in the midrapidity region using the sequential recombination k(T) and anti-k(T) as well as the SISCone jet finding algorithms with several resolution parameters in the range R = 0.2-0.6. Differential jet production cross sections measured with the three jet finders are in agreement in the transverse momentum (p(T)) interval 20 <p(T)(jet,ch) <100 GeV/c. They are also consistent with prior measurements carried out at the LHC by the ATLAS Collaboration. The jet charged particle multiplicity rises monotonically with increasing jet p(T), in qualitative agreement with prior observations at lower energies. The transverse profiles of leading jets are investigated using radial momentum density distributions as well as distributions of the average radius containing 80% (<R-80 >) of the reconstructed jet p(T). The fragmentation of leading jets with R = 0.4 using scaled p(T) spectra of the jet constituents is studied. The measurements are compared to model calculations from event generators (PYTHIA, PHOJET, HERWIG). The measured radial density distributions and <R-80 > distributions are well described by the PYTHIA model (tune Perugia-2011). The fragmentation distributions are better described by HERWIG.
  • Vegh, Russell B.; Bravaya, Ksenia B.; Bloch, Dmitry A.; Bommarius, Andreas S.; Tolbert, Laren M.; Verkhovsky, Michael; Krylov, Anna I.; Solntsev, Kyril M. (2014)
  • Hurmekoski, Elias; Sjolie, Hanne K. (2018)
    Scenario analyses are widely used in forest sector foresight studies, being typically based on either qualitative or quantitative approaches. As scenario analyses are used for informing decision-makers, it is of interest to contrast the similarities and differences between the scenario processes and outcomes using quantitative and qualitative approaches and to explore the underlying causes of differences. This paper uses the output from a qualitative scenario study to design forest sector model (FSM) scenarios and compares the results from the two approaches. We analyse two cases on wood products markets in Norway: i) Wood products suppliers establish a developer firm specializing on wood construction to boost demand, and ii) Levying a carbon tax while reducing CO2 emissions in cement production. Comparing the qualitative studies (innovation diffusion analysis, backcasting and Delphi) and FSM analyses (NorFor model), the results resemble for case ii) but deviate strongly for case i). Notably, the strategy aiming to boost the demand for domestic wood products leads in NorFor mainly to an increase in imports with limited impact on Norwegian sawnwood production. Causes of the discrepancies are discussed. Despite the challenges of combining the two frameworks, we believe that the method where assumptions based on stakeholder input or other qualitative research approaches are elaborated in a FSM and compared, should be more explored. Importantly, applying various methods and frameworks allows for complementing and diversifying the picture, and thus improving the knowledge base. (C) 2017 Department of Forest Economics, Swedish University of Agricultural Sciences, Umea. Published by Elsevier GmbH.
  • Lyashenko, A.; Safi, E.; Polvi, J.; Djurabekova, F.; Nordlund, K. (2020)
    Gaseous nitrogen is planned to be used as a seeding species to control the power flux in future fusion reactors with ITER-like divertors. Nitrogen interacts with the first wall materials, particularly with tungsten, leading to sputtering and changes of chemical composition of the material. We use the molecular dynamics methods with a recently developed WN potential to analyze the mechanisms leading to these modifications. We performed the simulations of cumulative nitrogen irradiation runs of tungsten surface. The sputtering yields obtained in our cumulative runs are in good agreement with experimental data. We observe the decrease of the tungsten sputtering yield with nitrogen accumulation and determine the reasons for the observed trend. The cluster analysis reveals the composition of the sputtered particles, suggesting the swift chemical sputtering process that occurs under the prolonged nitrogen irradiation of tungsten. We also observe and analyze the nitrogen saturation in the temperature range below the thermal stability limit. (C) 2020 Elsevier B.V. All rights reserved.
  • Kurkela, Aleksi; Vuorinen, Aleksi (2016)
    We generalize the state-of-the-art perturbative equation of state of cold quark matter to nonzero temperatures, needed in the description of neutron star mergers and core collapse processes. The new result is accurate to O(g(5)) in the gauge coupling, and is based on a novel framework for dealing with the infrared sensitive soft field modes of the theory. The zero Matsubara mode sector is treated via a dimensionally reduced effective theory, while the soft nonzero modes are resummed using the hard thermal loop approximation. This combination of known effective descriptions offers unprecedented access to small but nonzero temperatures, both in and out of beta equilibrium.
  • Nasibullin, R. T.; Valiev, R. R.; Faiskanova, K. M.; Stepanova, E.; Cherepanov, V. N.; Filimonov, V. D.; Sundholm, D. (2019)
    Acetyl protecting groups are commonly used in carbohydrate chemistry. Partially acetylated arylglycosides are not only useful building blocks in syntheses, but they are also substantial for plant metabolism. Nonselective base catalysis is often used for removing the acetyl groups. Even though acid-catalyzed deacetylation might be more selective, it is seldom used in carbohydrate chemistry, because it has not been thoroughly investigated. In this work, we study the acid-catalyzed deacetylation of per-acetylated phenyl glycosides experimentally and computationally by using density functional theory (DFT) calculations. Based on quantum modeling, we design a general scheme for the stepwise acid-catalyzed deacetylation of arylglycosides per-acetates. The approach can also be applied on gluco- and galactopyranosides. We have studied the deacetylation reaction in solvents of different polarity and found that the activation barriers of the stepwise deacetylation mechanism increase with increasing polarity of the solvent.
  • Heikinheimo, J.; Mizohata, K.; Räisänen, J.; Ahlgren, T.; Jalkanen, P.; Lahtinen, A.; Catarino, N.; Alves, E.; Tuomisto, Filip (2019)
    Reliable and accurate knowledge of the physical properties of elementary point defects is crucial for predictive modeling of the evolution of radiation damage in materials employed in harsh conditions. We have applied positron annihilation spectroscopy to directly detect mono-vacancy defects created in tungsten through particle irradiation at cryogenic temperatures, as well as their recovery kinetics. We find that efficient self-healing of the primary damage takes place through Frenkel pair recombination already at 35 K, in line with an upper bound of 0.1 eV for the migration barrier of self-interstitials. Further self-interstitial migration is observed above 50 K with activation energies in the range of 0.12-0.42 eV through the release of the self-interstitial atoms from impurities and structural defects and following recombination with mono-vacancies. Mono-vacancy migration is activated at around 550 K with a migration barrier of E-m(V) = 1.85 +/- 0.05 eV. (C) 2019 Author(s).