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AbstractMononuclear trivalent lanthanide complexes with formula [Ln(L)(NO3)3] [in which L=4,4‐difluoro‐8‐(2′:2′′;6′′:2′′′‐terpyridin‐4′′‐yl)‐1,3,5,7‐tetramethyl‐2,6‐diethyl‐4‐bora‐3a,4a‐diaza‐s‐indacene (Boditerpy)] are reported for Ln=Yb, Nd, Er, La and Gd. According to the crystal structure of the Yb complex, the lanthanide ion is bound to the terdentate terpyridine and the inner coordination sphere of the nine‐coordinate lanthanide ion is completed by three bidentate nitrate anions. The coordination polyhedron can be described as a distorted tricapped antiprism. The terpyridine chelate is almost planar and tilted by nearly 60° from the indacene subunit. FT‐IR spectra confirm the bidentate binding mode of the nitrate anions for the other complexes. NMR and ES‐MS spectra (through characteristic isotopic patterns) confirm the chemical formulation. The complexes have high molar absorption coefficients in the visible spectral region (65 000 M−1 cm−1 at 529 nm) and display sizeable NIR luminescence (900 to 1600 nm, for Ln=Yb, Nd and Er), upon irradiation through the electronic state of the indacene moiety at 514 nm. Crystal‐field splitting was analysed at low temperature. The quantum yield of the Yb solution (10−4 M) in dichloromethane amounts to 0.31 %, corresponding to a sensitisation efficacy of the ligand of ca. 63 %.

This study is to our knowledge the first to describe the effect of a Gas-Gas Heater (GGH) of a coal fired power plant's has on (i) the H2SO4 concentration and (ii) the particle/aerosol number concentration and particle size distribution present in the flue gas. In the absence of a GGH, homogenous nucleation takes places inside the Wet Flue Gas Desulphurisation (WFGD) converting the gaseous H2SO4 into aerosol H2SO4. This leads to a high aerosol number concentration behind the WFGD with 80% of the aerosols being smaller than 0.02 μm. This implies that an amine based carbon capture (CC) installation treating this flue gas can suffer from amine mist formation due to the high amount of available nuclei (i.e., H2SO4 aerosols) resulting in high amine emissions. In contrast, in the presence of a GGH not only 70% of the H2SO4 is removed from the flue gas (measured at the Nijmegen powerplant), but also homogenous nucleation in the WFGD is prevented resulting in low particle number concentrations. The flue gas leaving the GGH will not create any mist formation issues in an amine based CC installation due to the low amount of nuclei present in the flue gas. It is not the reduction in H2SO4 concentration by 70% inside the GGH as such that prevents mist formation but absence of H2SO4 in its aerosol form. These results are most likely quite widely transformable to other power plants that burn low sulfur coal i.e., around 0.7 weight%. This information will serve future pilot and demo CC installation around the world; in particular when retrofitted on power plants that have a GGH.

Abstract The need to shift from a fossil fuel based economy towards a more bio-based economy has received a lot of attention in public debates and policy making in recent years. However, there seems to be some inconsistency in how a bio-based economy is defined as well as how to estimate the size of this bio-based economy. The current article shows, using a Bibliometric analysis, that the topic "bio-based economy" does not come up extensively in the literature by mid 2010. Moreover, it seems that estimating the importance of the whole of a bio-based economy (and thereby not only focusing on one type of production or product) for a region or country is quite rare, besides a few examples. Within Flanders, one such study has been executed by order of the Flemish government. The current article suggests a framework that can be used to estimate the size of the bio-based economy in other regions or countries. It is based on several steps, so called critical points related to conceptualization, disaggregation, information and valuation. The critical points depend on who has and who wants the information, what the context is, what kind of data is available and whether the research should be comparable. The authors suggest that by following their proposed steps, a reliable estimate of the size of the bio-based economy can be calculated.

The measurement of the bulk minority carrier lifetime of semiconductors requires efficient passivation of the recombination states at the surface. While numerous recipes have been published for Si-surface passivation, no adequate passivation methods are available for Ge. This paper presents a new and straightforward passivation method, based on a solution of iodine in polyvinyl acetate and acetone. The dependence of the carrier lifetime with time after passivation and with Ge resistivity has been investigated. It is found that the lifetime in this low resistivity material is strongly governed by Auger recombination.

AbstractVegetation productivity first increases and then decreases with temperature; and temperature corresponding to the maximum productivity is called optimal temperature (Topt). In this study, we used satellite derived near‐infrared reflectance of vegetation (NIRv) data to map Topt of vegetation productivity at the spatial resolution of 0.1° on the Tibetan Plateau (TP), one of most sensitive regions in the climate system. The average Topt of non‐forest vegetation on the TP is about 14.7°C, significantly lower than the Topt value used in current ecosystem models. A remarkable geographical heterogeneity in Topt is observed over the TP. Higher Topt values generally appear in the north‐eastern TP, while the south‐western TP has relatively lower Topt (<10°C), in line with the difference of climate conditions and topography across different regions. Spatially, Topt tends to decrease by 0.41°C per 100 m increase in elevation, faster than the elevational elapse rate of growing season temperature, implying a potential CO2 regulation of Topt in addition to temperature acclimation. Topt increases by 0.66°C for each 1°C of rising mean annual temperature as a result of vegetation acclimation to climate change. However, at least at the decadal scale, there is no significant change in Topt between 2000s and 2010s, suggesting that the Topt climate acclimation may not keep up with the warming rate. Finally, future (2091–2100) warming could be close to and even surpass Topt on the TP under different RCP scenarios without considering potential climate acclimation. Our analyses imply that the temperature tipping point when the impact of future warming shifts from positive to negative on the TP is greatly overestimated by current vegetation models. Future research needs to include varying thermal and CO2 acclimation effects on Topt across different time scales in vegetation models.

Urban residents are exposed to higher levels of heat stress in comparison to the rural population. As this phenomenon could be enhanced by both global greenhouse gas emissions (GHG) and urban expansion, urban planners and policymakers should integrate both in their assessment. One way to consider these two concepts is by using urban climate models at a high resolution. In this study, the influence of urban expansion and GHG emission scenarios is evaluated at 100 m spatial resolution for the city of Brussels (Belgium) in the near (2031-2050) and far (2081-2100) future. Two possible urban planning scenarios (translated into local climate zones, LCZs) in combination with two representative concentration pathways (RCPs 4.5 and 8.5) have been implemented in the urban climate model UrbClim. The projections show that the influence of GHG emissions trumps urban planning measures in each period. In the near future, no large differences are seen between the RCP scenarios; in the far future, both heat stress and risk values are twice as large for RCP 8.5 compared to RCP 4.5. Depending on the GHG scenario and the LCZ type, heat stress is projected to increase by a factor of 10 by 2090 compared to the present-day climate and urban planning conditions. The imprint of vulnerability and exposure is clearly visible in the heat risk assessment, leading to very high levels of heat risk, most notably for the North Western part of the Brussels Capital Region. The results demonstrate the need for mitigation and adaptation plans at different policy levels that strive for lower GHG emissions and the development of sustainable urban areas safeguarding livability in cities.

A method is described for the quantification of major volatile substances in human breath without preconcentration. Methanol, ethanol, acetaldehyde and acetone are well separated by porous-layer open-tubular column gas chromatography. Low-level detection was possible by means of an ion trap detector. Halothane has been used as internal standard.

Abstract The numerical simulation of turbulent heat transfer in complex industrial flows represents a major challenge for RANS models. The impinging jet configuration is a popular test case for turbulence models, due to both the challenging nature of the flow field for the RANS approach and its widespread use in industrial applications. As a consequence, a large number of studies in the literature is dedicated to the assessment of a broad variety of turbulence models in this configuration. In particular, a significant effort has been put into the assessment of different closures for the turbulent momentum flux. In contrast, relatively little attention has been paid to the modelling of the turbulent heat flux term, and the classical Reynolds analogy is almost universally employed for this purpose despite its well-known limitations. Nevertheless, recently there has been a growing interest towards the development and assessment of more advanced closures for the turbulent heat flux. In this context, in the present work six turbulence models relying on different closures for both the turbulent momentum and heat fluxes have been used to simulate a planar impinging jet at unity, moderate and low Prandtl number and thoroughly assessed against a recently published reference DNS database. It is shown that the use of an advanced differential closure for the Reynolds stresses can result in an improvement in the prediction of the flow field. This, in turn, directly results in a more accurate prediction of the mean temperature at unity Prandtl number when the Reynolds analogy is employed for the closure of the turbulent heat flux. On the other hand, the inadequacy of the latter approach appears evident at low Prandtl values, and the necessity to account at least for the variability of the turbulent Prandtl number is demonstrated. It is then inferred that the most promising approach for such complex cases is represented by the combined use of anisotropic models for both the turbulent flow and the thermal fields.

Liquid phase hydrocarbon oxidation is one of the principal routes towards industrial organic chemicals. However, low product selectivity and associated by-product formation are major problems in several oxidation processes. As a result of the increasingly stringent environmental regulations, the development of oxidation catalysts has been a major challenge in the last decade. An overview of novel selective and clean oxidation catalysts and processes is presented.