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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)

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.

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.

The formation of nitrogen oxides from fuel-nitrogen through intermediates was studied by measuring first fuel-O/fuel-N ratios and nitrogen functionality in selected solid fuels. Then the ratios of the yields (fuel-N → HCN)/(fuel-N → NH3) in a nearly inert atmosphere at 800ºC in an entrained flow reactor was measured and finally the ratio (fuel-N → N2O)/(fuel-N → NO) in an oxidizing atmosphere at 800ºC The fuels studied were coal, brown coal, S- and C-type peat, fir bark, birch bark and pine bark, all milled to a particle size <63μm. The ratios of O/N in the fuel, measured by elemental analysis, ranged from 7 to 150. Nitrogen functionality (mass percent of the total nitrogen content) was determined by XPS. the (fuel-N → NCN)/(fuel-N → NH3) conversion ratio in the absence of O2, and also the (fuel-N → N2O)/(fuel-N → NO) conversion ratio with O2 present, decreased with increasing ratio of fuel-O/fuel-N, but neither ratio decreased regularly with the increasing ratio of pyrrolic to pyridinic nitrogen in the fuel. Thus, fuel-oxygen plays a more important role than nitrogen functionality in the chemistry of nitrogen oxide formation. The strong effect of (fuel-O/fuel-N) ratio on the (fuel-N → HCN)/(fuel-N → NH3) ratio may be due to the reaction between OH radicals and HCN to form NH3 near the fuel particle. The importance of this reaction is considered. Charring the fuel sample before combustion led to a sharp drop in the conversion of fuel-N to N2O compared with the virgin fuels. Thus, heterogeneous combustion reactions produced much less N2O than homogeneous combustion reactions.

A lake sediment record from the north-eastern European Russian Arctic was examined using palaeolimnological methods, including subfossil chironomid and diatom analysis. The objective of this study is to disentangle environmental history of the lake and climate variability during the past 2000 years. The sediment profile was divided into two main sections following changes in the lithology, separating the limno-telmatic phase between ~2000 and 1200 cal. yr BP and the lacustrine phase between ~1200 cal. yr BP and the present. Owing to the large proportion of semi-terrestrial chironomids and poor modern analogues, a reliable chironomid-based temperature reconstruction for the limno-telmatic phase was not possible. However, the lacustrine phase showed gradually cooling climate conditions from ~1200 cal. yr BP until ~700 cal. yr BP. The increase in stream chironomids within this sediment section indicates that this period may also have had increased precipitation that caused the adjacent river to overflow, subsequently transporting chironomids to the lacustrine basin. After a short-lived warm phase at ~700 cal. yr BP, the climate again cooled, and a progressive climate warming trend was evident from the most recent sediment samples, where the biological assemblages seem to have experienced an eutrophication-like response to climate warming. The temperature reconstruction showed more similarities with the climate development in the Siberian side of the Urals than with northern Europe. This study provides a characteristic archive of arctic lake ontogeny and a valuable temperature record from a remote climate-sensitive area of northern Russia.

The conversion of fuel-nitrogen to HCN and NH3 and to nitrogen oxides was studied with nitrogen-containing model compounds, chosen to represent the main nitrogen and oxygen functionalities in fossil fuels. Two kinds of experiments were performed in an entrained-flow reactor at 800 °C. The conversion of model-compound-N to HCN and NH3 was determined under inert conditions, and the formation of NO, N2O and NO2 was determined under oxidizing conditions. In inert atmosphere, oxygen-containing functional groups had an important effect on the ratio of HCN to NH3. In particular, OH groups bound directly in the ring structure increased the conversion of nitrogen to NH3. In oxidizing atmosphere, the conversions of model-compound-N to N2O were high, but the substituent groups had no well-defined effect on the ratio of N2O to NO. The formation of NO2 was insignificant.

Abstract The aim of the study was to explore the current forest industry's change features, necessary resources and management for the biorefining business in Scandinavia and North America. A total of 23 representatives from the forest, bioenergy and bioproducts sectors participated in themed interviews in the last round of a three-phase Delphi study. In both Scandinavian and North American forest industries, a conservative organizational culture and lack of financial resources create barriers to change. The role of the forest industry in the forest biorefinery consortium is largely seen to be that of a biomass provider. The scope of change depends on context-specific features, such as biorefinery location and raw material availability. Operating a commercial-scale biorefinery facility requires both new managerial and operational-level skills. Readiness for change needs to be embedded in the organizational culture — and the key to attaining this is open-minded organizational management. It is believed that there are innovative personnel in forest industry companies, yet the current culture does not encourage such people to submit their ideas. Success in the biorefinery business cannot be achieved without collaboration. However, sharing of profits among partners in the consortium will be challenging.

Anthropogenic climate warming has already affected the population dynamics of numerous species and is predicted to do so also in the future. To predict the effects of climate change, it is important to know whether productivity is linked to temperature, and whether species' traits affect responses to climate change. To address these objectives, we analysed monitoring data from the Finnish constant effort site ringing scheme collected in 1987-2013 for 20 common songbird species together with climatic data. Warm spring temperature had a positive linear relationship with productivity across the community of 20 species independent of species' traits (realized thermal niche or migration behaviour), suggesting that even the warmest spring temperatures remained below the thermal optimum for reproduction, possibly due to our boreal study area being closer to the cold edge of all study species' distributions. The result also suggests a lack of mismatch between the timing of breeding and peak availability of invertebrate food of the study species. Productivity was positively related to annual growth rates in long-distance migrants, but not in short-distance migrants. Across the 27-year study period, temporal trends in productivity were mostly absent. The population sizes of species with colder thermal niches had decreasing trends, which were not related to temperature responses or temporal trends in productivity. The positive connection between spring temperature and productivity suggests that climate warming has potential to increase the productivity in bird species in the boreal zone, at least in the short term.

Abstract Bio-coal has received generous amounts of media attention because it potentially allows greater biomass co-firing rates and net CO2 emission reductions in pulverised-coal power plants. However, little scientific research has been published on the feasibility of full-scale commercial production of bio-coal. Despite this, several companies and research organisations worldwide have been developing patented bio-coal technologies. Are the expectations of bio-coal realistic and are they based on accepted scientific data? This paper examines strictly peer-reviewed scientific publications in order to find an answer. The findings to date on three key properties of torrefied biomass are presented and reviewed. These properties are: the mass and energy balance of torrefaction, the friability of the product and the equilibrium moisture content of torrefied biomass. It is these properties that will have a major influence on the feasibility of bio-coal production regardless of reactor technology employed in production. The presented results will be of use in modelling commercial production of bio-coal in terms of economics and green-house gas emission balance.