Biogeomorphology in the field: bedforms and species, a mystic relationship

Fine-scale seabed mapping (Owenia fusiformis, and the razor clam Ensis directus) occur near bedload convergence zones resulting from a mutually evasive flood- and ebb-dominant channel system. Such zones are at the end of the channels, hence also fine grained sediments, food and larvae are trapped. The combination of the coarser-grained bedload with thedeposition of fines is indeed the optimum for a lot of suspension and detritus feeders. Still, highest abundances occur at the fringes of such a system where stress levels are intermediate. Hypotheses were successfully tested along the Dutch coastal zone. Those insights are important to assess changes in seafloor integrity and hydrographic conditions

A large synoptic dataset of coastal in situ observations

Since the beginning of 2004 MUMM has performed a series of moorings in the Belgian Coastal Zone with a tripod or benthic lander, equipped with a series of oceanographic sensors. Current meters such as an Acous1c Doppler Profiler (ADP) and an Acoustic Doppler Velocimeter (ADV), a CT-­sensor capable of measuring temperature and salinity, op1cal (OBS) and acous1c backsca\er sensors (ADP and ADV) to measure suspended sediment concentra1on, a LISST 100 suspended par1cle sizer, a passive Cetacean monitoring device (C-­PoD) and a passive sampling device for chemical monitoring have ever since been moored for more than 1750 days. From autumn 2009 a permanent coastal observatory has been installed at MOW1, located to the west of the entrance to the Zeebrugge harbor. Other mooring sites include more offshore loca1ons, such as the Kwintebank, Gootebank, MOW0 and the offshore windmill farms and a very nearshore loca1on (Blankenberge)

Impact evaluation of marine aggregate extraction through adaptive monitoring of bottom shear stress in bedform areas

Dedicated monitoring programmes are needed for the evaluation of the effects of the exploitation of non-living resources on the territorial sea and the continental shelf. Related to physical impacts, hydrodynamics and sediment transport, together with sedimentological and morphological evolution, need investigation. Overall aim is to increase process and system knowledge of both natural and exploited areas, with a particular focus on thecompliancy of extraction activities with respect to European Directives (e.g., European Marine Strategy Framework Directive and Habitat Directive). More specifically assessments are needed of changes in seafloor integrity and hydrographic conditions, two descriptors to define Good Environmental Status within Europe’sMarine Strategy Framework Directive.An important parameter is the bottom shear stress, with knowledge needed on both natural and anthropogenically induced variability. Bottom shear stress measurements are used for the validation of numerical models, necessary for impact quantification in the far field. Extensive data-model integration is critical for adequate assessments of the status of the marine environment, a prerequisite for sustainable use of living, and non-living resources

A morphological and size-based study of the changes of iron sulfides in the Caples and Torlesse Terranes (Otago Schist, New zealand) during prograde metamorphic evolution

It is widely accepted that metamorphism induces a remobilization of iron sulfides, sweeping away original ones while creating new ones. This paper analyzes size distributions of iron sulfides in several samples from the Caples and Torlesse terranes from the Otago Schist (New Zealand) using high-resolution X-ray computed tomography, which allows all iron sulfides larger than the resolution at which X-ray scans were performed to be characterized. Framboids and clusters of framboids are common in unmetamorphosed samples, but disappear in greenschist/amphibolite facies samples, where iron sulfides have anhedral habits. By contrast, the size and standard deviation of the new iron sulfides both remain within the same range. The results illuminate the evolution of iron sulfides throughout metamorphism, proposing boundaries for the metamorphic processes based on the shape of these iron sulfides

Annual variability in the seasonal cycles of chlorophyll, nutrients and zooplankton on the North-West European continental shelf

Seasonal cycles of salinity, nutrients, chlorophyll and zooplankton at 8 locations on the West-European shelf were analysed with respect to their timing and magnitude in the period 1980-1984. A late spring bloom with low chlorophyll values (2-4 mg.m-³) is observed in the Irish Sea, off the Scottish east coast and the Channel entrance. An early spring bloom and relatively high chlorophyll values (7-12 mg.m-³) are found in the southern Bight and the Skagerrak, whereas a late spring bloom with high chlorophyll concentrations (24 mg.m-³) is found along the Dutch and Belgian coast. In contrast to the other regions, the peak of the phytoplankton cycle in the German Bight (Helgoland) occurs in the summer period instead of the spring period. The peak in the yearly abundance of copepods shifts from May-June in the south to July-August in the north of the shelf. In the Irish Sea and the Channel entrance two seasonal copepods peaks are observed. The January nitrate values in Irish Sea, the southern Bight and the Skagerrak are about 20 % higher than those in the Atlantic input signal in the Channel entrance and east off Scotland. The January DIP values in these regions are comparable to those of the input signal, but the Irish Sea forms an exception here the level is increased by 10-20%. If compared with the Atlantic input signal the January values for nitrate and DIP at the Dutch and Belgium coast are about 10 and 4, and in the German Bight (Helgoland) 4 and 3 times higher, respectively. At most sites changes in the seasonal cycles of chorophyll coincide with changes in nutrient concentrations, wheras the maximum level of the seasonal signal is related to the nutrient levels

Investigation of Performance and Cavitation Treatment in a Kaplan Hydro Turbine

Cavitation is a phenomenon that occurs in various turbomachinery applications causing drawbacks on the. Some of these downsides are damaging the components of the system, generating noise and vibration, and loss of the turbine efficiency over time. Thus, it is imperative to address issue of cavitation to increase the life span of the equipment in addition to improve the system performance. This thesis introduces a method used to mitigate the cavitation phenomenon in a 3-inch Kaplan hydro turbine via injecting air at the leading edge of the rotor blades. The study is based on modeling the turbine using Computational Fluid Dynamics (CFD) software as well as carrying out experimental tests. The simulations were conducted at different air injection pressures over a spectrum of rotational speeds using Large Eddy Simulation (LES) for turbulence and volume of fluid for multiphase interactions: water, vapor water and air. The cavitation behavior was observed first without aeration, then followed by air injection simulations to investigate the effect of aeration. Each case was simulated for 12 cycles at rotational speeds of 1000, 2000, 3000, 4000, and 5000 rpm. The Vapor Volume Fraction (VVF) and the output mechanical power were monitored throughout the simulations. The data acquired from the simulations were compared to the experimental results for verifications. It was observed that the cavitation was mitigated in both the computer simulations and the experiment testing reaching up to 49.7% as an average reduction, while the output power was reduced by 6.6%

Transgenic Expression of P1A Induced Thymic Tumor: A Role for Onco-Fetal Antigens in Tumorigenesis

P1A is the first known tumor rejection antigen. It is expressed in embryonic stem cells and multiple tumors but is silent in adult tissues except for the testis and placenta. Therefore, P1A represents a prototype for onco-fetal antigens. To test the potential function of P1A in tumorigenesis, we used a transgenic mouse expressing P1A in lymphoid cells. We observed that immunodeficient host P1A transgenic mice developed thymic tumors after 7 months of age and had shorter survival rates compared to control groups. Most of the 7 examined tumors displayed B cell lineage markers. The P1A transgenic bone marrow cells had higher proliferation ability and more potential progenitors compared to control bone marrow cells. To our knowledge, our data provided the first example that onco-fetal antigen can promote tumorigenesis