2,463 research outputs found

    Modules for the education of civil engineers and the management of expert knowledge

    Get PDF
    In the focus of the Bologna-contract of the European secretaries of education the universities are invited to aim a unification and comparability of certificates and to offer compatible and cooperative models of education. Among existing lectures in the Internet there will arise a new competition between the universities in netbased teaching and learning environments. For the use of distributed sources of information and for the possibility to generate free configurable sequences of education modules you need management systems which are able to handle different formats of documents and to assemble it to consistent and valid lessons. Beside elementar viewing-functions, fusion of information also administrative tasks are needed, e.g. automated efficiency controls, adaptive learning surroundings. This paper attends to three aspects: - netbased teaching and learning in the area of the instruction of civil engineers - netbased information assembling and fusion of knowledge bases to higher level documents - netbased learning with international coordinated project

    The End Of Nucleosynthesis: Production Of Lead And Thorium In The Early Galaxy

    Get PDF
    We examine the Pb and Th abundances in 27 metal-poor stars (-3.1 56) enrichment was produced only by the rapid (r-) nucleosynthesis process. New abundances are derived from Hubble Space Telescope/Space Telescope Imaging Spectrograph, Keck/High Resolution Echelle Spectrograph, and Very Large Telescope/UV-Visual Echelle Spectrograph spectra and combined with other measurements from the literature to form a more complete picture of nucleosynthesis of the heaviest elements produced in the r-process. In all cases, the abundance ratios among the rare earth elements and the third r-process peak elements considered (La, Eu, Er, Hf, and Ir) are constant and equivalent to the scaled solar system r-process abundance distribution. We compare the stellar observations with r-process calculations within the classical "waiting-point" approximation. In these computations a superposition of 15 weighted neutron-density components in the range 23 <= log n(n) <= 30 is fit to the r-process abundance peaks to successfully reproduce both the stable solar system isotopic distribution and the stable heavy element abundance pattern between Ba and U in low-metallicity stars. Under these astrophysical conditions, which are typical of the "main" r-process, we find very good agreement between the stellar Pb r-process abundances and those predicted by our model. For stars with anomalously high Th/Eu ratios (the so-called actinide boost), our observations demonstrate that any nucleosynthetic deviations from the main r-process affect-at most-only the elements beyond the third r-process peak, namely Pb, Th, and U. Our theoretical calculations also indicate that possible r-process abundance "losses" by nuclear fission are negligible for isotopes along the r-process path between Pb and the long-lived radioactive isotopes of Th and U.Deutsche Forschungsgemeinschaft KR 806/13-1Helmholtz Gemeinschaft VH-VI-061U S National Science Foundation AST 07-07447, AST 06-07708Astronom

    Biogas Production From a Mixture of Cow Manure with Chicken Manure

    Full text link
    Biogas technology with zero waste concept is expected to be the alternative energy and to reduce environmental problems. The purpose of this study is to know the biogas yield per kilogram of each chicken and cow manure comparison. The study was conducted in six treatments with the addition of chicken manure of 0, 100, 300, 500, 700 and 1000 grams. The fermentation process is done using a batch system and biogas measurement was taken daily. The parameters to be observed were organic matter, the degree of acidity (pH), temperature, volume of biogas, biogas productivity, and C / N ratio of each treatment. The results showed that the overall pH at the beginning and end of the study tend to be close to neutral. The highest biogas yield was resulted from a mixture of chicken manure and cow manure at the composition of 1:1 or 50%:50% with biogas total amount of 35.690 ml and biogas productivity of 0,33 liters/g (volatile solid)

    Unterstützung der integrierten Gebäudeplanung und -verwaltung mit einem topologischen Kerndatenmodell

    Get PDF
    An einem Teil der Topologie architektonischer Räume, dem Volumenadjazenzgraphen (VAG), wird gezeigt wie topologisches Modellieren Anwendungen der Bauplanung integrieren kann. Dazu wird ein Prototyp vorgestellt, der im wesentlichen aus drei Komponenten besteht: Mit dem Anforderungsmanager werden Anforderungen eigegeben, die formal gut handhabbar sind. Mit dem Topologiemanager werden diese Anforderungen mit gezeichneten Räumen kombiniert. Die topologischen Relationen in den Zeichnungen werden mit den entsprechenden Mitteln des GIS berechnet und in eine Datenbank exportiert. Der Anforderungsprüfer vergleicht dann die Anforderungsdaten, die mit Hilfe des Anforderungsmanagers erzeugt wurden, mit den Topologiedaten. Dieser Ansatz soll zeigen, wie topologische Modelle eine Formalisierung semantisch hochstehender Informationen ermöglichen, indem sie als Eigenschaften von Graphen dargestellt werde

    Calculation of beam structures with the symbolic computer language Maple

    Get PDF
    Beside the standard calculation programs for civil engineering buildings mathematical programs have been lately established for the solution of differential equations for the analysis of mechanical and static systems. Programs like Maple, Matlab, MathCAD and Mathematica are popular in this field. To the knowledge of the authors, the widest application functionality offers the program Maple. Its advantages are, e.g. the alternatively symbolic or numerical solution of differential equation systems, the easy handling of parameter studies, the immediate visualization of results, the definition of macros for selected calculation steps and their export in other computer languages and, not least, the automatically generated, very clear documentation of the matehematical calculus

    Module fĂĽr die multimediale netzbasierte Baustatik-Lehre

    Get PDF
    In dem interdisziplinären und internationalen Verbundprojekt >2MN - Module für die multimediale netzbasierte HochschullehreEnvironment for Learning and TeachingDrehwinkeltrainerWörterbuch Bauwesen< erleichtert die Arbeit bei der Übersetzung baustatischer Fachtermini. Weitere Baustatik-Anwendungen, beispielsweise die Stabilitätsberechnung von Stabwerken, die Bestimmung von Querschnittswerten und die Berechnung von Biege- und Einflusslinien mit der Methode, können ortsunabhängig mit einem Pocket-PC genutzt werden

    Investigation of intraocular pressure fluctuation as a risk factor of glaucoma progression

    Get PDF
    Purpose: Since the role of short- and long-term intraocular pressure (IOP) fluctuation as a predictor of glaucoma progression is still controversial, the purpose of this study was to investigate the role of IOP fluctuation in a non-selected patient cohort. Materials and methods: Two-hundred and forty eyes of 120 glaucoma patients (51% female) with a mean age of 64.5 years were included. Inclusion criteria were at least a visual field (VF) and a 48-hour diurnal phasing of IOP including nocturnal measurement. Glaucoma Progression was defined as – if available – confirmed progression of reproducible VF defects in at least three VF examinations or increase of cup area on optic nerve imaging (Heidelberg Retina Tomograph [HRT]) with at least two images after baseline. If results were stable or less than previously mentioned VF or HRT examinations were available, it was classified as “no progression”. Results: Glaucoma progression was seen in seven of 240 eyes in the VF analysis and ten of 240 eyes on HRT. Of all 240 eyes, 92 and 41 eyes fulfilled the criteria to be included for progression evaluation on VF and HRT analysis, respectively. Mean time to progression ± standard error was 3.6±0.2 years on VF and 4.5±0.3 years on HRT. Univariate and multivariate Cox regression analyses revealed short-term IOP fluctuation (P,0.0001) and maximum IOP (P,0.001) as risk factors for glaucoma progression on VF. There was no significant influence of demographic characteristics, ocular or general health on glaucoma progression. Conclusion: Short-term IOP fluctuation was associated with the progression of glaucoma in this non-selected cohort of glaucoma patients receiving phasing of IOP. Keywords: glaucoma progression, short-term IOP fluctuation, long-term IOP fluctuation, glaucoma imaging, visual fiel

    Recurrence of paraproteinemic keratopathy after penetrating keratoplasty and its assessment with confocal microscopy

    Get PDF
    Purpose To report on a case of recurrence of paraproteinemic keratopathy (PPK) associated with monoclonal gammopathy after bilateral penetrating keratoplasty. Observations Penetrating keratoplasty was performed on both eyes of a 45-year-old man due to bilateral progressive corneal stromal clouding. Recurrence of the corneal stromal opacities accompanied by a decrease in visual acuity was observed on slit-lamp examination already two years after penetrating keratoplasty. Confocal laser scanning microscopy (CLSM) of the corneal grafts performed three years after penetrating keratoplasty showed bilateral morphological changes identical to that found in the patient&#039;s corneas prior to penetrating keratoplasty. A hematological work-up revealed monoclonal gammopathy of type IgG kappa. The histochemical examination of the explanted corneas confirmed the diagnosis of PPK. Conclusions and importance Paraproteinemic keratopathy is an underdiagnosed ophthalmological condition, which may be associated with potentially life-threatening hematologic disorders. A hematological workup should be performed in patients with corneal opacities of uncertain etiology. Penetrating keratoplasty should be performed with caution in patients with monoclonal gammopathy due to the possibility of a very fast recurrence of PPK in the corneal graft. This is the first presentation of the recurrence of flake like PPK after penetrating keratoplasty assessed with CLSM
    • …
    corecore