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1	Theoretical and experimental studies on the hygroscopic properties of soot particles sampled from a kerosene diffusion flame : impact of the aging processes by O3 and SO2 / Etudes théoriques et expérimentales sur les propriétés hygroscopiques de particules de suie prélevées sur une flamme de diffusion de kérosène : impact des processus de vieillissement de l'O3 et du SO2 Wu, Junteng 26 April 2019 (has links) Les particules de suie émises par les processus de combustion sont hydrophobes. Cependant leurs caractéristiques morphologiques et chimiques sont modifiées lorsqu’elles séjournent dans l’atmosphère. Elles peuvent alors devenir des noyaux de condensation (CCN) ou glaciogènes (IN) et contribuer de manière significative au forçage radiatif indirect affectant le climat. Pour les aérosols sphériques et mono dispersés, la théorie de k-Köhler est souvent utilisée pour quantifier les propriétés hygroscopiques des aérosols. Dans ce travail une approche théorique et expérimentale est proposée afin d’étendre la théorie à des distributions de tailles et de morphologies d’aérosols plus complexes. Les propriétés hygroscopiques des particules sont déterminées en mesurant leur fraction activée en fonction de la sursaturation en eau au moyen d’un compteur de CCN. Le modèle développé est d’abord testé sur des particules sphériques et isolées de sulfate d’ammonium. Puis il est appliqué aux agrégats complexes de particules de suie. Les suies sont générées dans une flamme de diffusion de kérosène, et ensuite exposées à des concentrations variables d’ozone et de dioxyde de soufre dans des conditions contrôlées de température, pression et humidité relative. La mobilité électrique, la morphologie et la composition chimique de surface sont mesurés par granulométrie, microscopie électronique et spectrométrie de masse par ion secondaires respectivement, avant et après le vieillissement, et reliées au processus d’activation. A partir de la comparaison entre les courbes d’activation et le modèle, les valeurs du paramètre d’hygroscopicité k ont été déterminées pour une large gamme de conditions opératoires. / Freshly emitted soot particles from combustion processes are hydrophobic. However, the aging process in the atmosphere can modify their size, morphology and surface chemistry and turn them into efficient cloud condensation (CCN) and ice nuclei (IN) that significantly contribute to the indirect radiative forcing of climate. For spherical and monodisperse aerosols, k-Köhler theory is often used in the literature to quantify the hygroscopic properties of aerosols. In this work, a combined theoretical and experimental approach is proposed to add to the theory the contributions of the particle size distribution and morphology. Hygroscopic properties of the particles are derived by measuring their activated fraction as a function of the water supersaturation using a CCN counter. The model developed in this work is first tested on dry ammonium sulfate particles (quasi spherical and non aggregating). Then, it is applied to soot particles that are complex aggregates of primary particles. Soot particles are generated from a laboratory diffusion jet flame supplied with kerosene, and aged with ozone and sulfur dioxide in controlled conditions of temperature, pressure and relative humidity to simulate their permanence in the atmosphere. The electrical mobility, morphology and chemical composition of fresh and aged soot are measured by scanning mobility particle sizing, electron microscopy and secondary ion mass spectrometry, respectively, before and after the aging and related to the activation process. From the comparison of the experimental activation curves and the model, the values of the hygroscopicity parameter k could be determined for a large variety of operating conditions. Hygroscopicité Théorie de Köhler 551.511
2	Bibliothek und Sparkasse Bürger, Thomas 20 December 2011 (has links) (PDF) Am 31. Oktober 2011, dem Reformationstag, strahlte Großenhain in schönster Oktobersonne. Die Alte Lateinschule neben der großen Marienkirche hatte geöffnet, um die Jubiläumsausstellung über den wohl berühmtesten Sohn der Stadt, Karl Benjamin Preusker, zu präsentieren. Und auch die Preusker-Bibliothek öffnete ihre Türen weit und lud ein zum Stöbern und Flanieren im Lese- und Kräutergarten. Aufgeschlagen lag in der historischen Amtsstube Preuskers das Goldene Buch der Stadt zum Eintrag des Bundespräsidenten a.D. Prof. Horst Köhler. Mit der Preusker-Medaille des Jahres 2011 ehrten die Stadt Großenhain und der Dachverband der Institutionen- und Personalverbände des deutschen Bibliothekswesens „Bibliothek & Information Deutschland“ (BID) den früheren Bundespräsidenten, der sich sehr erfolgreich für die Bibliotheken engagiert hatte. Horst Köhler Karl-Preusker-Medaille Großenhain ddc:020 rvk:AN 65600
3	Beyond Köhler theory : Molecular dynamics simulations as a tool for atmospheric science Hede, Thomas January 2013 (has links) In this thesis, the results from molecular dynamics (MD) simulations of nanoaerosol clusters are discussed. The connecting link of these studies is the Köhler theory, which is the theory of condensational growth and activation of cloud droplets to form clouds. By investigating parameters such as the surface tension, state of mixture and morphology of nanoaerosol particles, conclusions can be drawn to improve the Köhler theory to include the effects of organic compounds previously unaccounted for. For the terrestrial environment, the simulations show that the natural surfactant cis-pinonic acid, an oxidation product evaporated from boreal trees, spontaneously accumulates at the surface of nanoaerosol clusters and thereby reduces the surface tension. The surface tension depression is related to the concentration of the surfactant and the size of the clusters. Surface tension is an important parameter of the Köhler theory. A decrease of the surface tension can lower the critical water vapour supersaturation needed for cloud droplet activation, giving rise to more, but smaller cloud droplets (Twomey effect) which in turn could change the optical properties of the cloud. It was also shown that the three organic surfactants, being model compounds for so called Humic-like substances (HULIS) have the ability to form aggregates inside the nanoaerosol clusters. These HULIS aggregates can also promote the solubilization of hydrophobic organic carbon in the form of fluoranthene, enabling soot taking part in cloud drop formation. Dissolved intermediately surface-active free amino acids were shown to be of some relevance for cloud formation over remote marine areas. The MD simulations showed differences between the interacting forces for spherical and planar interfaces of amino acids solutions. This thesis has emphasized the surface-active properties of organic compounds, including model HULIS and amino acids and their effect on surface tension and molecular orientation including aggregate formation in nanoaerosol clusters and their activation to form droplets. This thesis shows that the Köhler equation does not fully satisfactory describe the condensational growth of nano-sized droplets containing organic surfactants. Different approaches are suggested as revisions of the Köhler theory. / <p>At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 3: Submitted. Paper 5: Manuscript.</p> Köhler theory molecular dynamics surface tension aggregate climate
4	Konstrukce mikroskopového LED osvětlovacího zdroje / Design of Microscope LED Illumination Source Bartoň, Luboš January 2013 (has links) This master’s thesis deals with the construction design of microscope episcopic LED illumination source and subsequent functional sample realization. Illumination source is compatible with industrial microscope Nikon Eclipse LV150 and designed as a replacement for halogen light source. Way of collecting light is chosen with respect to search analysis results and collector optical element and LED is selected with respect to the analysis of the episcopic illuminator. Two construction designs are designed with respect to the results of photometric analyzes. Optimal design is realized and compared with used lighting sources – halogen and xenon.
5	Bibliothek und Sparkasse: Horst Köhler erhielt in Großenhain die Karl-Preusker-Medaille Bürger, Thomas 20 December 2011 (has links) Am 31. Oktober 2011, dem Reformationstag, strahlte Großenhain in schönster Oktobersonne. Die Alte Lateinschule neben der großen Marienkirche hatte geöffnet, um die Jubiläumsausstellung über den wohl berühmtesten Sohn der Stadt, Karl Benjamin Preusker, zu präsentieren. Und auch die Preusker-Bibliothek öffnete ihre Türen weit und lud ein zum Stöbern und Flanieren im Lese- und Kräutergarten. Aufgeschlagen lag in der historischen Amtsstube Preuskers das Goldene Buch der Stadt zum Eintrag des Bundespräsidenten a.D. Prof. Horst Köhler. Mit der Preusker-Medaille des Jahres 2011 ehrten die Stadt Großenhain und der Dachverband der Institutionen- und Personalverbände des deutschen Bibliothekswesens „Bibliothek & Information Deutschland“ (BID) den früheren Bundespräsidenten, der sich sehr erfolgreich für die Bibliotheken engagiert hatte. info:eu-repo/classification/ddc/020 ddc:020
6	Towards an understanding of the cloud formation potential of carbonaceous aerosol: laboratory and field studies Padro Martinez, Luz Teresa 21 August 2009 (has links) It is well known that atmospheric aerosols provide the sites for forming cloud droplets, and can affect the Earth's radiation budget through their interactions with clouds. The ability of aerosols to act as cloud condensation nuclei is a strong function of their chemical composition and size. The compositional complexity of aerosol prohibits their explicit treatment in atmospheric models of aerosol-cloud interactions. Nevertheless, the cumulative impact of organics on CCN activity is still required, as carbonaceous material can constitute up to 90% of the total aerosol, 10-70% of which is water soluble. Therefore it is necessary to characterize the water soluble organic carbon fraction by CCN activation, droplet growth kinetics, and surface tension measurements. In this thesis, we investigate the water soluble properties, such as surface tension, solubility, and molecular weight, of laboratory and ambient aerosols and their effect on CCN formation. A mechanism called Curvature Enhanced Solubility is proposed and shown to explain the apparent increased solubility of organics. A new method, called Köhler Theory Analysis, which is completely new, fast, and uses minimal amount of sample was developed to infer the molar volume (or molar mass) of organics. Due to the success of the technique in predicting the molar volume of laboratory samples, it was applied to aerosols collected in Mexico City. Additionally the surface tension, CCN activity, and droplet growth kinetics of these urban polluted aerosols were investigated. Studies performed for the water soluble components showed that the aerosols in Mexico City have surfactants present, can readily become CCN, and have growth similar to ammonium sulfate. Finally, aerosols from three different polluted sources, urban, bovine, and ship emissions, were collected and characterized. The data assembled was used to predict CCN concentrations and access our understanding of the system. From these analyses, it was evident that knowledge of the chemical composition and mixing state of the aerosol is necessary to achieve agreement between observations and predictions. The data obtained in this thesis can be introduced and used as constraints in aerosol-cloud interaction parameterizations developed for global climate models, which could lead to improvements in the indirect effect of aerosols. Köhler theory analysis Aerosols Activation kinetics Organic Water soluble organic compounds Activation CCN closure Hygroscopicity Cloud condensation nuclei Atmospheric aerosols Molecular volume
7	Programovatelná osvětlovací soustava pro optický mikroskop / Programmable illuminating system for an optical microscope Lošťák, Martin January 2008 (has links) A programmable illuminating system (PIS) uses a commercial multimedia projector together with a suitable optical relay system in order to illuminate specimens under microscope with transmitted light. The theoretical part of the diploma thesis describes some methods used in the optical transmission microscopy. All of these methods employ physical masks placed in the condenser front focal plane. In the case of the traditional methods the masks are used to enhance contrast (e.g. dark-field illumination) and resolution (oblique illumination). One of the methods (a condenser with rotating aperture) provides the information about the three-dimensionality of the specimen. The next part of the thesis contains the theory and the basic classification of the illuminating systems used in the optical transmission microscopy. An optical and mechanical design of the optical relay system used for PIS is introduced. The experimental part shows the results made with two different PIS arrangements. It was shown on two different specimens that the PIS provides the same illumination as the classical methods. It was also proved that the PIS can simulate the rotating aperture in the condenser front focal plane and thus to give the information about the three-dimensionality of the specimen. Some new static and dynamic illuminating methods were introduced.
8	Shaping the field Perlina, Anna 18 November 2016 (has links) Die vorliegende wissenschaftliche Arbeit rekonstruiert die Entwicklung der deutschen Psychologie zwischen der Eröffnung des ersten psychologischen Labors in 1879 und der Gleichschaltung durch das Nazi-Regime in den 1930er Jahren. Die Dissertation stellt den konzeptuellen und methodologischen Rahmen der psychologischen Disziplin anhand von drei Generationen von Pionierforschung dar. Hierbei wird herausgearbeitet, wie sich die frühe experimentelle Psychologie einen eigenen Platz zwischen den Natur- und Geisteswissenschaften kreiert. Die gestaltpsychologische Schule spielt darin eine entscheidende Rolle. Der zentrale Fokus der Arbeit liegt in der historischen Periode zwischen 1922 und 1936, über welche sich Kurt Lewins Untersuchungen zur Handlungs- und Affektpsychologie erstrecken. In dieser deutschen Schaffensperiode wurden der theoretische und methodologische Rahmen, sowie praktische experimentelle Designs erschaffen, welche die amerikanische Arbeit Lewins entscheidend prägten. Der Aufbau von Lewins berühmter Feldtheorie wird im Detail rekonstruiert. Die Dissertation zeigt auf, wie Lewin originelle psychologische Konzepte aus interdisziplinärer Erfahrung formte, und wie experimentelle Praktiken der Zeit die Entstehung eines immer komplexer werdenden Konzeptgerüstes herbeiführten. Anschließend wird die Bedeutung des Gestalt-Lewin-Falles für die Psychologiegeschichte erörtert. In die langfristige Wissenschaftsgeschichte ist Lewins Arbeit nicht etwa als gebündeltes Forschungsgebiet eingegangen. Stattdessen ist sie in so unterschiedliche Bereiche wie Entwicklungs- und Persönlichkeitspsychologie, Soziologie und Wirtschaftsmanagement eingeflossen und hat diese geprägt. / This dissertation represents a historical reconstruction of the development and transformation of German experimental psychology between the emergence of the first experimental laboratory in 1879 and its Gleichschaltung by the Nazi regime in the 1930s. It traces the evolution of the conceptual as well as the experimental framework of psychology over the course of these years following three generations of experimental research. Hereby, the work attempts to grasp how early experimental psychology negotiated its place between the humanities and the natural sciences. The project’s major focus lies in the period between 1922 and 1936, in which Kurt Lewin’s Berlin Experimental Program on Action and Emotions took place. The work specifically investigates the process of constitution of Lewin’s field theory, a system of concepts coined by Lewin in order to study psychological processes underlying human conduct. The dissertation shows how Lewin’s concepts emerged out of interdisciplinary sources, and how experimental practices in psychology triggered the emergence of new knowledge. Eventually, it is shown how the investigated historical case of Gestalt psychology in Berlin fits into and plays a decisive role in the long-term development of experimental psychology. Verhalten Behaviorismus Wissenschaftsgeschichte Sozialpsychologie Feldtheorie Feld Lewin Kurt Lewin Gestalt Gestaltpsychologie Geschichte der Psychologie Gestaltschule experimentelle Psychologie Interdisziplinarität Gestalttheorie Koffka Wertheimer Köhler Wolfgang Köhler Kurt Koffka Max Wertheimer Tamara Dembo Bluma Zeigarnik Amerikanische Psychologie behavioristische Psychologie Stimulus-response Berliner Experimentalprogramm experimentelles Labor interaktives design interaktives Experiment Weimar Republik Handlungspsychologie Affektpsychologie Verhaltenspsychologie Konzeptsystem Wissenstransformation Psychologiegeschichte behaviorism Weimar Republic history of science Field theory field Lewin Kurt Lewin Gestalt Gestalt psychology history of psychology Gestalt school experimental psychology interdisciplinarity action and emotions Gestalt theory Koffka Wertheimer Koehler Wolfgang Koehler Kurt Koffka Max Wertheimer Tamara Dembo Bluma Zeigarnik American psychology behaviorist psychology stimulus-response Berlin Experimental Program experimental laboratory interactive design interactive experiment human conduct transformation of knowledge system of concepts social psychology 900 Geschichte CM 2000 ddc:900

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