Adaptive Local Refinement with Octree Load Balancing for the Parallel Solution of Three-Dimensional Conservation Laws

Conservation laws are solved by a local Galerkin finite element procedure with adaptive space-time mesh refinement and explicit time integration. The Courant stability condition is used to select smaller time steps on smaller elements of the mesh, thereby greatly increasing efficiency relative to methods having a single global time step. Processor load imbalances, introduced at adaptive enrichment steps, are corrected by using traversals of an octree representing a spatial decomposition of the domain. To accommodate the variable time steps, octree partitioning is extended to use weights derived from element size. Partition boundary smoothing reduces the communications volume of partitioning procedures for a modest cost. Computational results comparing parallel octree and inertial partitioning procedures are presented for the three-dimensional Euler equations of compressible flow solved on an IBM SP2 computer.     

Mikroskopischer Nachweis von Aleuronk?rnern im Mehl durch F?rbung

Zusammenfassung In den Getreidekörnern finden sich Aleuronkörner in der Aleuronschicht und im Keim.Mit Hilfe organischer Farbstoffe, wie Chinalizarin, Titangelb und Azoblau, welche in alkalischer Lösung mit Magnesium charakteristische farbige Verbindung geben, kann man Aleuronkörner im Mehl nachweisen auf mittelbare Art durch entsprechende Färbung der Globoide, die Magnesiumverbindungen enthalten.Im alkalischen Reagens lösen sich die Stärke und die Bestandteile der Aleuronkörner auf, ebenso wie die Gesamthaut, die Grundmasse und die Krystalloide. Die Globoide, welche am meisten ihren Eiweißcharakter verloren haben, lösen sich nicht in verdünnter Lauge auf und färben sich bei Chinalizarin kornblumenblau, bei Titangelb rosa und bei Azoblau violett.Die gefärbten Globoide werden schon bei geringer mikroskopischer Vergrößerung deutlich sichtbar in Gestalt von gesammelter Masse, lokalisiert in den Zellen oder in lose verstreuten Kügelchen, welche bei starker Vergrößerung wie innen hohl erscheinen. Nach der Menge der gefärbten Globoide kann man die Anwesenheit von Aleuronkörnern annehmen und daraufhin den Wert des untersuchten Mehles beurteilen.Die Proben in vitro zwecks Unterscheidung des Magnesiums in Globoiden im Getreidemehl vom Mehl anderer Herkunft (Kartoffel-, Sago-, Bananen-, Maranta-und Tapiocamehl) lieferten keine positiven Ergebnisse. Diese beiden Arten von Mehlen kann man mit Hilfe der mikroskopischen Methode unterscheiden.     

A central fission pathway in alkylphenol ethoxylate biodegradation

A representative alkylphenol Triton X-100 (having 9.5 oxyethylene subunits) was treated over 40 days under the conditions of the continuous flow activated sludge simulation test in a plant with aeration and denitrification chambers. Treated sewage was separated by sequential extraction with ethyl acetate and chloroform. The extracts were analysed by high-performance liquid chromatography-electrospray ionisation-mass spectrometry (HPLC-ESI-MS). Single ion chromatograms of the chloroform extracts showed the presence of neutral, mono- and di-carboxylated poly(ethylene glycols). This is evidence of the central fission of alkylphenol ethoxylates (APE). Simultaneously, the APE having omega-carboxylated oxyethylene chains were identified. This is the evidence that apart from central fission, the omega-oxidation oxyethylene chain pathway also occurs.     

Field-programmable logic devices with optical input-output

A field-programmable logic device (FPLD) with optical I/O is described. FPLD's with optical I/O can have their functionality specified in the field by means of downloading a control-bit stream and can be used in a wide range of applications, such as optical signal processing, optical image processing, and optical interconnects. Our device implements six state-of-the-art dynamically programmable logic arrays (PLA's) on a 2 mm x 2 mm die. The devices were fabricated through the Lucent Technologies-Advanced Research Projects Agency-Consortium for Optical and Optoelectronic Technologies in Computing (Lucent/ARPA/COOP) workshop by use of 0.5-mum complementary metal-oxide semiconductor-self-electro-optic device technology and were delivered in 1998. All devices are fully functional: The electronic data paths have been verified at 200 MHz, and optical tests are pending. The device has been programmed to implement a two-stage optical switching network with six 4 x 4 crossbar switches, which can realize more than 190 x 10(6) unique programmable input-output permutations. The same device scaled to a 2 cm x 2 cm substrate could support as many as 4000 optical I/O and 1 Tbit/s of optical I/O bandwidth and offer fully programmable digital functionality with approximately 110,000 programmable logic gates. The proposed optoelectronic FPLD is also ideally suited to realizing dense, statically reconfigurable crossbar switches. We describe an attractive application area for such devices: a rearrangeable three-stage optical switch for a wide-area-network backbone, switching 1000 traffic streams at the OC-48 data rate and supporting several terabits of traffic.     

Bubble domains in remanence state in monocrystalline, epitaxial ferrite layers/MgMnFe/3O4

Magnetic domain structure was studied in monocrystalline, epitaxial ferrite layers of spinel structure for MgMn-ferrites using magnetic colloid technique. The layers, 6 micrometers thick, were obtained by CVD on monocrystalline MgO substrates. Layers obtained at 1550°K exhibit growth- and stress-induced anisotropy. The domain structure was studied in the demagnetized and remanence states, and on applying a static magnetic field of up to 2 KOe perpendicularly to the layer. In the remanence state, bubble domains 3+4 micrometers in diameter form a hexagonal lattice. In the demagnetized state, after AC-demagnetization, the bubbles are 1 micrometers in diameter and form a regular lattice. Both lattices are stable in magnetic fields of less than 100 Oe. The bubble mobility, measured by the ferromagnetic resonance method, is about 250 cm/Oe s.