FM1 (1)-FM1 (541) : Archives centrales. Recueil d'hommages se rapportant à Victor Hugo

Photocopies.

The Effects of Headcut and Knickpoint Propagation on Bridges in Iowa, TR-541, 2008

The overarching goal of the proposed research was to provide a predictive tool for knickpoint propagation within the HCA (Hungry Canyon Alliance) territory. Knickpoints threaten the stability of bridge structures in Western Iowa. The study involved detailed field investigations over two years in order to monitor the upstream migration of a knickpoint on Mud Creek in Mills County, IA and identify the key mechanisms triggering knickpoint propagation. A state-of-the-art laser level system mounted on a movable truss provided continuous measurements of the knickpoint front for different flow conditions. A pressure transducer found in proximity of the truss provided simultaneous measurements of the flow depth. The laser and pressure transducer measurements led to the identification of the conditions at which the knickpoint migration commences. It was suggested that negative pressures developed by the reverse roller flow near the toe of the knickpoint face triggered undercutting of the knickpoint at this location. The pressure differential between the negative pressure and the atmospheric pressure also draws the impinging jet closer to the knickpoint face producing scour. In addition, the pressure differential may induce suction of sediment from the face. Other contributing factors include slump failure, seepage effects, and local fluvial erosion due to the exerted fluid shear. The prevailing flow conditions and soil information along with the channel cross-sectional geometry and gradient were used as inputs to a transcritical, one dimensional, hydraulic/geomorphic numerical model, which was used to map the flow characteristics and shear stress conditions near the knickpoint. Such detailed flow calculations do not exist in the published literature. The coupling of field and modeling work resulted in the development of a blueprint methodology, which can be adopted in different parts of the country for evaluating knickpoint evolution. This information will assist local government agencies in better understanding the principal factors that cause knickpoint propagation and help estimate the needed response time to control the propagation of a knickpoint after one has been identified.

Animadversiones nonnullae in Iliadis Homericae XVIII: 509-541

Arkit: 1 arkintunnukseton lehti, A4 B1.

Na 50 Nachlass Arthur Schopenhauer - 'Schopenhauer-Archiv', 541 - Konzeptschreiben an Erdmann und dem Meyer-Verlag in Leipzig zwecks Zusendung der Biographie

u.a.: Johanna Schopenhauer; Heinrich Floris Schopenhauer; Gottlieb Ernst Schulze; Justus Radius;

Na 50 Nachlass Arthur Schopenhauer - 'Schopenhauer-Archiv', 897 - Übersendung der Information einer Anklage gegen Karl Gutzkow wegen Beleidigung von Verstorbenen

u.a. Angaben zum Charakter Schopenhauers; Erkundigung nach Verwandte Schopenhauers;

Na 1 Nachlass Max Horkheimer, 541 - Korrespondenzen mit Leo Löwenthal (p. VI 16, 1 - 146)

109 Briefe zwischen Leo Löwenthal und Max Horkheimer, 1943; 4 Briefe von der Office War Information (Washington) an Leo Löwenthal, Januar 1943; 1 Brief von J. H. Randall an Leo Löwenthal, 24.11.1942; 1 Brief von Dan Levin an Leo Löwenthal, 10.01.1943;

Solar radiation over and under sea ice and photographic quantification of Ice algal aggregates during the POLARSTERN cruise ARK-XXVII/3 (IceArc) in summer 2012

The ice cover of the Arctic Ocean has been changing dramatically in the last decades and the consequences for the sea-ice associated ecosystem remain difficult to assess. Algal aggregates underneath sea ice have been described sporadically but the frequency and distribution of their occurrence is not well quantified. We used upward looking images obtained by a remotely operated vehicle (ROV) to derive estimates of ice algal aggregate biomass and to investigate their spatial distribution. During the IceArc expedition (ARK-XXVII/3) of RV Polarstern in late summer 2012, different types of algal aggregates were observed floating underneath various ice types in the Central Arctic basins. Our results show that the floe scale distribution of algal aggregates in late summer is very patchy and determined by the topography of the ice underside, with aggregates collecting in dome shaped structures and at the edges of pressure ridges. The buoyancy of the aggregates was also evident from analysis of the aggregate size distribution. Different approaches used to estimate aggregate biomass yield a wide range of results. This highlights that special care must be taken when upscaling observations and comparing results from surveys conducted using different methods or on different spatial scales.