Bedform migration in a mixed sand and cohesive clay intertidal environment and implications for bed material transport predictions

Many coastal and estuarine environments are dominated by mixtures of non-cohesive sand and cohesive mud. The migration rate of bedforms, such as ripples and dunes, in these environments is important in determining bed material transport rates to inform and assess numerical models of sediment transport and geomorphology. However, these models tend to ignore parameters describing the physical and biological cohesion (resulting from clay and extracellular polymeric substances, EPS) in natural mixed sediment, largely because of a scarcity of relevant laboratory and field data. To address this gap in knowledge, data were collected on intertidal flats over a spring-neap cycle to determine the bed material transport rates of bedforms in biologically-active mixed sand-mud. Bed cohesive composition changed from below 2 vol% up to 5.4 vol% cohesive clay, as the tide progressed from spring towards neap. The amount of EPS in the bed sediment was found to vary linearly with the clay content. Using multiple linear regression, the transport rate was found to depend on the Shields stress parameter and the bed cohesive clay content. The transport rates decreased with increasing cohesive clay and EPS content, when these contents were below 2.8 vol% and 0.05 wt%, respectively. Above these limits, bedform migration and bed material transport was not detectable by the instruments in the study area. These limits are consistent with recently conducted sand-clay and sand-EPS laboratory experiments on bedform development. This work has important implications for the circumstances under which existing sand-only bedform migration transport formulae may be applied in a mixed sand-clay environment, particularly as 2.8 vol% cohesive clay is well within the commonly adopted definition of “clean sand”

Code of practice for electrical and electronic installations in boats

SIGLEAvailable from British Library Document Supply Centre- DSC:94/05988 / BLDSC - British Library Document Supply Centre2. edGBUnited Kingdo

Integrierter Netzschutz zur Erhoehung der Verfuegbarkeit des Schiffsantriebes Abschlussbericht

SIGLEAvailable from TIB Hannover: F01B228+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie, Bonn (Germany)DEGerman

INasS - Integrierte Navigation auf schnellen Schiffen. ET3: Computer-based Training Schlussbericht

SIGLEAvailable from TIB Hannover: F04B127 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Bildung und Forschung, Berlin (Germany)DEGerman

INasS - Integrierte Navigation auf schnellen Schiffen. ET1: Verbesserte automatische Erfassung und Verfolgung von Radarzielen Schlussbericht

Available from TIB Hannover: F04B125 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEBundesministerium fuer Bildung und Forschung, Berlin (Germany)DEGerman

INasS - Integrierte Navigation auf schnellen Schiffen. ET2: Teleservice Schlussbericht

Available from TIB Hannover: F04B126 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEBundesministerium fuer Bildung und Forschung, Berlin (Germany)DEGerman

The Design and Development of an Irish Sea Passenger-Ferry-Based Oceanographic Measurement System

An evolving coastal observatory has been hosted by the National Oceanography Centre at Liverpool, United Kingdom, for more than nine years. Within this observatory an instrumented ferry system has been developed and operated to provide near-surface scientific measurements of the Irish Sea. Passenger vessels such as ferries have the potential to be used as cost-effective platforms for gathering high-resolution regular measurements of the properties of near-surface water along their routes. They are able to operate on an almost year-round basis, and they usually have a high tolerance to adverse weather conditions. Examples of the application of instrumented ferry systems include environmental monitoring, the generation of long-term measurement time series, the provision of information for predictive model validation, and data for model assimilation purposes. This paper discusses the development of an engineering system installed on board an Irish Sea passenger ferry. Particular attention is paid to explaining the engineering development required to achieve a robust, automated measuring system that is suitable for long-term continuous operation. The ferry, operating daily between Birkenhead and Belfast or Dublin, United Kingdom, was instrumented between December 2003 and January 2011 when the route was closed. Measurements were recorded at a nominal interval of 100 m and real-time data were transmitted every 15 min. The quality of the data was assessed. The spatial and temporal variability of the temperature and salinity fields are investigated as the ferry crosses a variety of shelf sea and coastal water column types

Electric Propulsion- and Power Plant (EP3) - (Dieselelektrische Schiffsantriebsanlagen) Schlussbericht. Bd. 1-2

The project investigates high-tech electric propulsion systems for marine vessels which are low-cost in production and operation. High availability of these drives is to improve safety and reliability of marine transport. Specific circuiting components are to save volume and weight of the main electric components. The component efficiency is to be improved especially in part-load operation. The failure probability of marine propulsion systems decreases parallel to the number of components, so that omission of components (e.g. transformers) will enhance both the system efficiency and its availability. The network quality will be improved for all new electric propulsion systems as compared to the status quoDas Ziel des Vorhabens ist, fuer verschiedene Schiffstypen hochtechnologische E-Hauptantriebe zu schaffen, die kostenguenstig in Herstellung und Betrieb sind. Durch eine hohe Verfuegbarkeit dieser Antriebe soll eine verbesserte Schiffssicherheit erreicht werden. Der Einsatz spezieller Schaltungskonzepte soll zu Raum- und Gewichtseinsparungen der elektrischen Hauptkomponenten fuehren. Der Wirkungsgrad der Anlagen soll insbesondere im Teillastbereich verbessert werden. Die Gesamtausfallwahrscheinlichkeit des Schiffsantriebes sinkt mit der Verringerung der Komponenten. Die Einsparung von Komponenten in der Energieuebertragungskette (z.B. Transformatoren) wirkt sich nicht nur positiv auf den Wirkungsgrad aus, sondern erhoeht auch die Verfuegbarkeit der Gesamtanlage. Die Netzqualitaet soll bei allen vorgenannten neuen E-Fahrantriebsloesungen gegenueber dem Stand der Technik verbessert werden. (orig.)Available from TIB Hannover: F99B377+a: F99B378+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEBundesministerium fuer Bildung und Forschung (BMBF), Bonn (Germany)DEGerman