Search

The acoustic field resulting from the interaction of a thin flexible structure with a turbulent flow was investigated both numerically and experimentally. Two different model configurations were considered: in one a flexible plate acted as a moving wail in a turbulent boundary layer, and in the other the flexible plate was located in the wake of a square cylinder. The fully coupled simulation of the fluid--structure--acoustics interaction was based on a partitioned approach employing two different simulation codes: a finite-volume flow solver of second-order accuracy in space and time and a finite-element structural-mechanics and acoustics solver. A code coupling interface was used for the exchange of data between the different discretizations. The experiments were performed in an acoustic wind tunnel employing microphone measurements of the sound pressure level. Detailed flow measurements were carried out using laser Doppler anemometry and three-component hot-wire anemometry. The flow-induced vibration of the flexible structure was measured with a laser-scanning vibrometer. Experimental and numerical results characterizing the flow field, the structural vibration, and the generated sound are presented. DOI: 10.2514/1.40344

Most applications of xMAP™ (Luminex®) bead-based assay technology in diagnostics and drug discovery use immobilized antigens or antibodies. Here the authors describe the development of novel assay systems in which [...]

The effect of crystal anisotropy on wetting angles of equilibrium silicate melts on crystal faces of spinel, diopside, enstatite and olivine has been determined experimentally by the sessile melt drop technique. The anisotropy, [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII], of solid-liquid interfacial energies ([gamma]SL(max)--[gamma]SL(min)) can be related to the wetting angles, [psi], by [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII]. Normalising to the smallest wetting angle gives values of Pw for diopside = 0.0728, olivine = 0.0574, orthopyroxene = 0.0152, and spinel = 0.0075. Crystal anisotropy influences grain-scale morphology of small-degree partial melts, permeability and the melt connectivity threshold, [empty set].sub.C]. Results show that, at sufficient melt fractions, diopside should increase permeability in a peridotitic matrix, whereas enstatite should lower it. Despite its low anisotropy, spinel contributes positively to permeability and [[empty set].sub.C] because of its high surface energies. These results suggest that harzburgitic mineral matrices typical of the subcratonic mantle should impede the movement of low-degree partial melts, whereas melts should flow more easily through spinel lherzolites.

Byline: Frank Schafer, Annalisa Manera The test facility CIRCUS (CIRculation Under Start-up) was built to study the start-up phase of a natural-circulation BWR. During the start-up,so-called flashing-induced instabilities can arise. These instabilities are induced by flashing (i.e., steam production in adiabatic conditions) of the coolant in the long riser section, which is placed above the core to enhance the flow rate. The flashing that occurs in the riser causes an imbalance between driving force and pressure losses in the natural-circulation loop, giving rise to flow oscillations. Within the European-Union 5th Framework Programme, a project, NACUSP (Natural circulation and stability performance of BWRs), has been started in December 2000, having as one of its main aims the understanding of the physics of the phenomena involved during the start-up phase of natural-circulation-cooled BWRs, providing a large experimental database and validating state-of-the-art thermo-hydraulic codes in the low-pressure, low-power operational region of these reactors. One part of this project deals with the modelling of selected CIRCUS tests using the thermo-hydraulic code ATHLET (Analysis of THermal-hydraulics of LEaks and Transients). This paper gives an overview about experiments and simulations. The code ATHLET is used to investigate the dynamic behaviour of the CIRCUS test facility and the results of the calculations are compared with the experimental data.

We present the case of a 49-year-old man with a bicuspid aortic valve who presented to the emergency department with limb weakness and a fever. Blood tests revealed a fulminant septic process with Haemophilus parainfluenzae bacteraemia, anaemia and thrombocytopenia. Imaging revealed a cervical spinal abscess and discitis causing spinal cord compression, in addition to multiple cerebral septic emboli, pleural effusions and ascites. A transoesophageal echocardiogram (TOE ) performed post decompression of his spinal collection showed native aortic valve endocarditis with an associated large aortic root abscess. He underwent successful aortic valve surgery and a 6-week course of antibiotic therapy and made an excellent clinical recovery with no long-term complications from his condition. [ABSTRACT FROM AUTHOR]

The authors report the case of an 87-year-old lady who presented with a right middle cerebral artery territory infarct in whom the authors diagnosed a probable ruptured blood cyst attached to her anterior mitral valve leaflet, with the use of trans-thoracic and trans-oesophageal echocardiography. Embolic strokes are recognised as a rare complication of intracardiac blood cysts, with very few cases previously reported. Echocardiography was first used to identify a blood cyst in 1983 and remains an excellent modality to diagnose this rare condition. [ABSTRACT FROM AUTHOR]

Methods based on immobilized-metal affinity chromatography (IMAC) technology for the isolation of 6xHis-tagged proteins offer a one-step purification process that is both robust and meets the challenge of quantitatively purifying thousands of proteins with differing structures and characteristics. To perform this method in a high-throughput, automated format, protocols have been developed that can be run on lab automation workstations. Ready-to-run protocols covering a wide range of protein purification and assay applications, and which rely on the well-established 6xHis-Ni-NTA IMAC technology, are available. An Ni-NTA magnetic bead-based protocol allows micro-scale purification of up to 15 microg of 6xHis-tagged protein per well. If larger amounts of purified protein are needed, a vacuum-controlled Ni-NTA resin-based process provides a convenient medium-scale method for purification of up to 300 microg of 6xHis-tagged protein in a 96-well format. This protocol has been adapted to further increase the yield of 6xHis-tagged proteins allowing purification of up to several milligrams of highly pure protein per well. The protocol can process 96 samples, each derived from up to 25 mL culture volume (E. coli), in less than 3 h. Examples of purification and assay applications using the protocols mentioned above, and data on reproducibility and cross-contamination-free processing are shown.