Browsing by Author "Hoffmann, T."
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- ItemAn alternative to field retting: Fibrous materials based on wet preserved hemp for the manufacture of composites(Basel : MDPI AG, 2019) Gusovius, H.-J.; Lühr, C.; Hoffmann, T.; Pecenka, R.; Idler, C.A process developed at the Leibniz Institute for Agricultural Engineering and Bioeconomy (ATB) for the supply and processing of wet-preserved fiber plants opens up new potential uses for such resources. The processing of industrial hemp into fiber materials and products thereof is undergoing experimental research along the value-added chain from the growing process through to the manufacturing of product samples. The process comprises the direct harvesting of the field-fresh hemp and the subsequent anaerobic storage of the entire plant material. Thus, process risk due to unfavorable weather conditions is prevented in contrast to common dew retting procedures. The effects of the anaerobic storage processes on the properties of the bast part of the plant material are comparable to the results of common retting procedures. Harvest storage, as well as further mechanical processing, leads to different geometrical properties compared to the bast fibers resulting from traditional post harvesting treatment and decortication. The fiber raw material obtained in this way is well suited to the production of fiberboards and the reinforcement of polymer or mineral bonded composites. The objective of this paper is to present recent research results on final products extended by a comprehensive overview of the whole supply chain in order to enable further understanding of the result influencing aspects of prior process steps.
- ItemErforschung und Realisierung von innovativen hybridintegrierten Diodenlaser-Komponenten und Systemen (INDILAS), Teilvorhaben: Halbleiterkomponenten zur Erzeugung von definierten optischen ps-Impulsfolgen hoher Brillanz auf der Basis modengekoppelter Laser (KomodLa) : InDiLAS/KoModLa ; Schlussbericht ; Laufzeit des Vorhabens: 01.06.2009 - 31.05.2012(Hannover : Technische Informationsbibliothek (TIB), 2012) Erbert, G.; Klehr, A.; Schwertfeger, S.; Wenzel, H.; Liero, A.; Hoffmann, T.[no abstract available]
- ItemThe formation, properties and impact of secondary organic aerosol: Current and emerging issues(München : European Geopyhsical Union, 2009) Hallquist, M.; Wenger, J.C.; Baltensperger, U.; Rudich, Y.; Simpson, D.; Claeys, M.; Dommen, J.; Donahue, N.M.; George, C.; Goldstein, A.; Hamilton, J.F.; Herrmann, H.; Hoffmann, T.; Iinuma, Y.; Jang, M.; Jenkin, M.E.; Jimenez, J.L.; Kiendler-Scharr, A.; Maenhaut, W.; McFiggans, G.; Mentel, Th.F.; Monod, A.; Prévôt, A.S.H.; Seinfeld, J.H.; Surratt, J.D.; Szmigielski, R.; Wildt, J.Secondary organic aerosol (SOA) accounts for a significant fraction of ambient tropospheric aerosol and a detailed knowledge of the formation, properties and transformation of SOA is therefore required to evaluate its impact on atmospheric processes, climate and human health. The chemical and physical processes associated with SOA formation are complex and varied, and, despite considerable progress in recent years, a quantitative and predictive understanding of SOA formation does not exist and therefore represents a major research challenge in atmospheric science. This review begins with an update on the current state of knowledge on the global SOA budget and is followed by an overview of the atmospheric degradation mechanisms for SOA precursors, gas-particle partitioning theory and the analytical techniques used to determine the chemical composition of SOA. A survey of recent laboratory, field and modeling studies is also presented. The following topical and emerging issues are highlighted and discussed in detail: molecular characterization of biogenic SOA constituents, condensed phase reactions and oligomerization, the interaction of atmospheric organic components with sulfuric acid, the chemical and photochemical processing of organics in the atmospheric aqueous phase, aerosol formation from real plant emissions, interaction of atmospheric organic components with water, thermodynamics and mixtures in atmospheric models. Finally, the major challenges ahead in laboratory, field and modeling studies of SOA are discussed and recommendations for future research directions are proposed.
- ItemGeneral overview: European Integrated project on Aerosol Cloud Climate and Air Quality interactions (EUCAARI) – integrating aerosol research from nano to global scales(München : European Geopyhsical Union, 2011) Kulmala, M.; Asmi, A.; Lappalainen, H.K.; Carslaw, K.S.; Pöschl, U.; Baltensperger, U.; Hov, Ø.; Brenquier, J.-L.; Pandis, S.N.; Facchini, M.C.; Hansson, H.-C.; Wiedensohler, A.; O'Dowd, C.D.; Boers, R.; Boucher, O.; de Leeuw, G.; Denier van der Gon, H.A.C.; Feichter, J.; Krejci, R.; Laj, P.; Lihavainen, H.; Lohmann, U.; McFiggans, G.; Mentel, T.; Pilinis, C.; Riipinen, I.; Schulz, M.; Stohl, A.; Swietlicki, E.; Vignati, E.; Alves, C.; Amann, M.; Ammann, M.; Arabas, S.; Artaxo, P.; Baars, H.; Beddows, D.C.S.; Bergström, R.; Beukes, J.P.; Bilde, M.; Burkhart, J.F.; Canonaco, F.; Clegg, S.L.; Coe, H.; Crumeyrolle, S.; D'Anna, B.; Decesari, S.; Gilardoni, S.; Fischer, M.; Fjaeraa, A.M.; Fountoukis, C.; George, C.; Gomes, L.; Halloran, P.; Hamburger, T.; Harrison, R.M.; Herrmann, H.; Hoffmann, T.; Hoose, C.; Hu, M.; Hyvärinen, A.; Hõrrak, U.; Iinuma, Y.; Iversen, T.; Josipovic, M.; Kanakidou, M.; Kiendler-Scharr, A.; Kirkevåg, A.; Kiss, G.; Klimont, Z.; Kolmonen, P.; Komppula, M.; Kristjánsson, J.-E.; Laakso, L.; Laaksonen, A.; Labonnote, L.; Lanz, V.A.; Lehtinen, K.E.J.; Rizzo, L.V.; Makkonen, R.; Manninen, H.E.; McMeeking, G.; Merikanto, J.; Minikin, A.; Mirme, S.; Morgan, W.T.; Nemitz, E.; O'Donnell, D.; Panwar, T.S.; Pawlowska, H.; Petzold, A.; Pienaar, J.J.; Pio, C.; Plass-Duelmer, C.; Prévôt, A.S.H.; Pryor, S.; Reddington, C.L.; Roberts, G.; Rosenfeld, D.; Schwarz, J.; Seland, Ø.; Sellegri, K.; Shen, X.J.; Shiraiwa, M.; Siebert, H.; Sierau, B.; Simpson, D.; Sun, J.Y.; Topping, D.; Tunved, P.; Vaattovaara, P.; Vakkari, V.; Veefkind, J.P.; Visschedijk, A.; Vuollekoski, H.; Vuolo, R.; Wehner, B.; Wildt, J.; Woodward, S.; Worsnop, D.R.; van Zadelhoff, G.-J.; Zardini, A.A.; Zhang, K.; van Zyl, P.G.; Kerminen, V.-M.In this paper we describe and summarize the main achievements of the European Aerosol Cloud Climate and Air Quality Interactions project (EUCAARI). EUCAARI started on 1 January 2007 and ended on 31 December 2010 leaving a rich legacy including: (a) a comprehensive database with a year of observations of the physical, chemical and optical properties of aerosol particles over Europe, (b) comprehensive aerosol measurements in four developing countries, (c) a database of airborne measurements of aerosols and clouds over Europe during May 2008, (d) comprehensive modeling tools to study aerosol processes fron nano to global scale and their effects on climate and air quality. In addition a new Pan-European aerosol emissions inventory was developed and evaluated, a new cluster spectrometer was built and tested in the field and several new aerosol parameterizations and computations modules for chemical transport and global climate models were developed and evaluated. These achievements and related studies have substantially improved our understanding and reduced the uncertainties of aerosol radiative forcing and air quality-climate interactions. The EUCAARI results can be utilized in European and global environmental policy to assess the aerosol impacts and the corresponding abatement strategies.
- ItemA new feedback mechanism linking forests, aerosols, and climate(München : European Geopyhsical Union, 2004) Kulmala, M.; Suni, T.; Lehtinen, K.E.J.; Dal Maso, M.; Boy, M.; Reissell, A.; Rannik, Ü.; Aalto, P.; Keronen, P.; Hakola, H.; Bäck, J.; Hoffmann, T.; Vesala, T.; Hari, P.The possible connections between the carbon balance of ecosystems and aerosol-cloud-climate interactions play a significant role in climate change studies. Carbon dioxide is a greenhouse gas, whereas the net effect of atmospheric aerosols is to cool the climate. Here, we investigated the connection between forest-atmosphere carbon exchange and aerosol dynamics in the continental boundary layer by means of multiannual data sets of particle formation and growth rates, of CO2 fluxes, and of monoterpene concentrations in a Scots pine forest in southern Finland. We suggest a new, interesting link and a potentially important feedback among forest ecosystem functioning, aerosols, and climate: Considering that globally increasing temperatures and CO2 fertilization are likely to lead to increased photosynthesis and forest growth, an increase in forest biomass would increase emissions of non-methane biogenic volatile organic compounds and thereby enhance organic aerosol production. This feedback mechanism couples the climate effect Of CO2 with that of aerosols in a novel way.
- ItemVerbundprojekt: Komponenten für gepulste Faserlaser mit erweitertem zeitlichen und spektralen Parameterbereich (FaZit), Teilvorhaben: Untersuchung der technologisch-physikalischen Grundlagen von elektronischen und optoelektronischen Halbleiterkomponenten zur Erzeugung und definierten Einstellung von kurzen Lichtimpulsen hoher Brillanz (HaKomPuls) : Schlussbericht ; FaZiT/HaKomPuls(Hannover : Technische Informationsbibliothek (TIB), 2012) Erbert, G.; Wenzel, H.; Klehr, A.; Schwertfeger, S.; Liero, A.; Hoffmann, T.[no abstract available]