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Meteorological forcing at the air-water interface is the main determinant of the heat balance of most lakes (Edinger et al., 1968; Sweers, 1976). Year-to-year changes in the weather therefore have a major effect on the thermal characteristics of lakes. However, lakes that differ with respect to their morphometry respond differently to these changes (Gorham, 1964), with deeper lakes integrating the effects of meteorological forcing over longer periods of time. Other important factors that can influence the thermal characteristics of lakes include hydraulic residence time, optical properties and landscape setting (e.g. Salonen et al., 1984; Fee et al., 1996; Livingstone et al., 1999). These factors modify the thermal responses of the lake to meteorological forcing (cf. Magnuson et al., 2004; Blenckner, 2005) and regulate the patterns of spatial coherence (Chapter 17) observed in the different regions (Livingstone, 1993; George et al., 2000; Livingstone and Dokulil, 2001; Jarvinen et al., 2002; Blenckner et al., 2004)

Molecular dynamics (MD) computer simulations are used routinely to compute atomistic trajectories of complex systems. Systems are simulated in various ensembles, depending on the experimental conditions one aims to mimic. While constant energy, temperature, volume, and pressure are rather straightforward to model, pH, which is an equally important parameter in experiments, is more difficult to account for in simulations. Although a constant pH algorithm based on the $\lambda$-dynamics approach by Brooks and co-workers was implemented in a fork of the GROMACS molecular dynamics program, uptake has been rather limited, presumably due to the poor scaling of that code with respect to the number of titratable sites. To overcome this limitation, we implemented an alternative scheme for interpolating the Hamiltonians of the protonation states that makes the constant pH molecular dynamics simulations almost as fast as a normal MD simulation with GROMACS. In addition, we implemented a simpler scheme, called multisite representation, for modeling side chains with multiple titratable sites, such as imidazole rings. This scheme, which is based on constraining the sum of the $\lambda$-coordinates, not only reduces the complexity associated with parameterizing the intra-molecular interactions between the sites, but is also easily extendable to other molecules with multiple titratable sites. With the combination of a more efficient interpolation scheme and multisite representation of titratable groups, we anticipate a rapid uptake of constant pH molecular dynamics simulations within the GROMACS user community.

We examined long-term relationships between Cladocera and limnogeological and climate variables in a late Holocene lake sediment sequence to assess cladoceran responses to climate change and reconstruct past climate variations in southern Finland, near the Baltic Sea coast. Elemental composition, organic matter, and inferred water quality variables were used to constrain paleoenvironmental (until 4500 cal BP) conditions and human impact. Fossil Cladocera assemblages, ephippia, and body size trends were utilized to estimate mean July air temperature (T Jul) variability, open-water season length, and water-temperature regimes. Results revealed stable cladoceran communities, dominated by Eubosmina, until 500 cal BP, followed by major assemblage changes including increases in Chydorus cf. sphaericus, Alonella spp., and Bosmina longirostris. Pb and Cu concentrations were associated temporally with increasing human impact and warming climate during the past few centuries, and were the most significant factors in explaining cladoceran community changes, based on redundancy analysis. A Cladocera-based T Jul reconstruction estimated elevated temperatures for the end of the Holocene Thermal Maximum, a cooler period during ~3000–2000 cal BP, slightly increased temperatures during 1200–800 cal BP corresponding to the Medieval Climate Anomaly (MCA), and lower temperatures during the Little Ice Age (LIA), 800–200 cal BP. The reconstruction also suggests that significant climate warming took place during the twentieth century. Cladocerans mostly associated with warm periods included B. longirostris and Pleuroxus uncinatus, whereas Alona affinis, A. quadrangularis, and C. cf. sphaericus were associated with colder climate. Compared to a reference Chironomidae-inferred T Jul reconstruction from the same region, discrepancies were apparent in amplitude of temperature change, as the temperature variability in the cladoceran-based record was muted until ~200 cal BP. During the LIA, increased ephippia and body size agreed with the temperature reconstruction, but suggested a severely shorter open-water season and reduced water temperatures compared to the preceding late Holocene episodes, even though the cladoceran T Jul showed quite similar temperatures for these periods. Our results suggest that fossil cladoceran assemblages, ephippia, and morphological attributes respond sensitively to long-term climate fluctuations and this record reflects well the major climate events of the late Holocene and provides realistic paleoclimatic estimates for maritime southern Finland.

The aim of this study was to evaluate climate impacts of a typical Finnish wind farm. Three research questions were: 1) What is the typical Finnish wind farm’s carbon footprint? 2) what is the energy payback time of the typical Finnish wind farm? and 3) does the typical Finnish wind farm have a better net-negative impact on climate than the commercial forest area on which it was built? Data for the study were collected via academic literature, wind turbine life cycle assessment reports, geographic information system (GIS) analysis and through the Natural Resources Institute Finland’s Statistics database. The GIS analysis was conducted to retrieve the volume of roundwood on the wind farm’s site. The carbon footprint of the typical Finnish wind farm was found to be 7,18 g CO2e/kWh and the wind farm’s energy payback time 7,06 months. This study found that during 22 years (consisting of the wind farm’s construction and operation phases) the typical Finnish wind farm had a net-negative impact on climate change of at least 169 767,72 t CO2. In the absence of the typical Finnish wind farm, producing the equivalent amount of electricity by Finnish electricity mix was considered in calculating the net impact of the commercial forest area. This resulted in a net-positive impact on climate change of 192 393,42 t CO2. However, the typical Finnish wind farm did not represent a carbon sink. Climate impacts represent only a part of environmental impacts caused by wind power. The results of this study might have implications for the acceptability of wind power by general society as well as used for calculating climate impact assessment. Tutkimuksen tavoitteena oli arvioida tyypillisen suomalaisen tuulivoimapuiston ilmastovaikutuksia. Aihetta lähestyttiin kolmella tutkimuskysymyksellä selvittäen tuulivoimapuiston 1) hiilijalanjälki ja 2) energiantakaisinmaksuaika sekä 3) onko puistolla parempi nettonegatiivinen ilmastovaikutus kuin talousmetsällä, johon se on rakennettu. Tutkimuksen aineisto kerättiin akateemisen kirjallisuuden, elinkaariarviointi-raporttien, paikkatieto-analyysin (GIS) ja Luonnonvarakeskuksen tietokannan avulla. GIS-analyysillä selvitettiin runkopuun määrä tuulivoimapuistoalueella. Tyypillisen suomalaisen tuulivoimapuiston hiilijalanjälki on tulosten perusteella 7,18 g CO2e/kWh ja tuulivoimapuiston energiantakaisinmaksuaika 7,06 kuukautta. Tutkimuksessa havaittiin, että 22 vuoden aikana (puiston rakentaminen ja tuotantovaihe) tyypillisellä suomalaisella tuulivoimapuistolla on nettonegatiivinen ilmastovaikutus, joka on vähintään 169 767,72 t CO2. Skenaariossa, että tuulivoimapuistoa ei rakennettaisi, talousmetsän ilmastovaikutusten laskennassa on huomioitu vastaava sähkömäärän tuotto suomalaisella energialähteiden yhdistelmällä. Tässä tapauksessa netto-positiivinen vaikutus on tulosten perusteella 192 393,42 t CO2. Tuloksia ei voi kuitenkaan tulkita niin, että tuulivoimapuisto olisi hiilinielu. Ilmastovaikutukset ovat yksi osa tuulivoiman aiheuttamista ympäristövaikutuksista. Tämän tutkielman tuloksilla voidaan hyödyntää ilmastovaikutusten arvioinnin laskennassa ja niillä olla osaltaan vaikutuksia siihen, kuinka tuulivoima nähdään yhteiskunnassa. ei tietoa saavutettavuudesta unknown accessibility

In this paper, we consider both energy efficiency and security issues in a wireless power transfer (WPT) enabled relay system. In the considered system, the multiple-antenna decode-and-forward relay node (RN) has both information decoding and wireless power recycling capabilities, and thus can be empowered by WPT and assist the transmission from the multiple-antenna base station (BS) to the mobile terminals (MTs). In addition, we consider that there is an eavesdropper between the BS and the RNs, which tries to overhear the information sent to the MTs. We formulate a joint optimization problem with the objective to optimize energy efficiency of the presented system by considering WPT time allocation, power allocation, and secrecy data rate. In particular, we propose to select RNs based on different assigned priorities so that the physical layer security of information transmission can be guaranteed. Moreover, we take into consideration of the cases that the RNs adopt the half- and full-duplex protocols, and study the corresponding system performance analytically. The proposed schemes are evaluated by extensive simulations and it is demonstrated that the proposed resource allocation schemes can obtain energy efficiency maximization, and have superior performance over other schemes.

As the concept for circular economy gains traction in the world and the EU pushes for the transition from a linear economy to a circular economy model, the role of waste-toenergy is crucial in a circular economy as it is the last chance to extract value out of material at the same time as providing an alternative energy source, henceforth bringing together a closed-loop system. A functioning circular economy will also have minimal waste generated which is sync with the idea of zero-waste. How all these aspects really work together is the focal point of this Master’s thesis where the aim is to see how the three factors of waste-to-energy, the circular economy and a zero-waste goal work together in accomplishing their respective objectives and to access their performance and potential in Finland using other Nordic countries as benchmarks. A qualitative research method of four semi-structured interviews with experts in Finland involved in various circular economy was supported by secondary sourced data on the other Nordic countries and if found that WtE has additional benefits to Nordics compared to other countries due to district heating utilization of excess steam that provides heat during the long winter months so henceforth offers higher energy efficiency. The state of the circular economy in Finland was harder to ascertain with the difficulty in showing concrete examples of a CE due to misunderstanding of the relatively new theoretical term and the many related terms. The overall conclusion for Finland was that a zero-waste goal was not the correct aim to have as this could still mean high incineration, instead Finland should look at the exemplarily example of Denmark which aims to be incineration free in the future. There would still be a role for WtE, only to a less extent, dealing with hazardous and residual waste. The role of recycling will grow in line with a true CE model which means that energy sourced from WtE will decline, As a result Finland should plan accordingly and invest less in WtE infrastructure and more in other alternative energy sources.

The observed difference in the selectivity towards alkane, ketone, and alcohol hydrodeoxygenation products over Ru and Rh catalysts is explored using a combination of density functional theory and microkinetics. Using γ-valerolactone as a model compound, we investigate the reaction mechanism in order to identify selectivity determining species. The effect of the coadsorbed water molecule as well as the higher adsorbate surface coverage on reaction barriers and energies is explored as well. The performed calculations suggest that the desired alkane product is formed from a ketone intermediate on Ru, and through both ketone and alcohol on Rh, although the selectivity towars alkane on Rh is much lower than on Ru. peerReviewed

AbstractBio‐based chemicals can be produced from furfural through hydrotreatment. In this study, 2‐methylfuran (MF), a potential biofuel component, was produced with Pt, Ru, and Ni catalysts supported on wood‐based activated carbons. The catalytic hydrotreatment experiments were conducted in a batch reactor at 210–240 °C with 2‐propanol as solvent and 40 bar H2 pressure. Two types of activated carbon supports were prepared by carbonization and activation of lignocellulosic biomass (forest‐residue‐based birch and spruce from Finland). Both types of activated carbons were suitable as catalyst supports, giving up to 100 % furfural conversions. The most important factors affecting the MF yield were the metal dispersion and particle size as well as reaction temperature. The highest observed MF yields were achieved with the noble metal catalysts with the highest dispersions at 240 °C after 120 min reaction time: 3 wt % Pt on spruce (MF yield of 50 %) and 3 wt % Ru on birch (MF yield of 49 %). Nickel catalysts were less active most likely owing to lower dispersions and incomplete metal reduction. Interesting results were obtained also with varying the metal loadings: the lower Pt loading (1.5 wt %) achieved almost the same MF yield as the 3 wt % catalysts, which can enable the production of MF with high yields and reduced catalyst costs. Based on this study, biomass‐based renewable activated carbons can be used as catalyst supports in furfural hydrotreatment with high conversions.