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101.
Eva Lantsoght Cor van der Veen Ane de Boer Dick Hordijk 《Structure and Infrastructure Engineering》2017,13(9):1130-1145
A large number of existing reinforced concrete solid slab bridges in the Netherlands are found to be insufficient for shear upon assessment. However, research has shown additional sources of capacity in slab bridges, increasing their total capacity and possibly changing their failure mode. Previous testing was limited to half-scale slab specimens cast in the laboratory. To study the full structural behaviour of slab bridges, testing to failure of a bridge is necessary. Research on load testing is carried out in order to develop load testing guidelines. In August 2014, a bridge was tested in two spans. The bridge was load tested, and additional cycles until yielding occurred in the reinforcement were added to the experiment. Though calculations with current design provisions showed that the bridge could fail in shear, the field test showed failure in flexure before shear. The unity check for flexure was determined. The experiment shows that the methods for rating of existing reinforced concrete slab bridges are conservative. 相似文献
102.
103.
John Dolbow Isaac Harari 《International journal for numerical methods in engineering》2009,78(2):229-252
A stabilized finite element method based on the Nitsche technique for enforcing constraints leads to an efficient computational procedure for embedded interface problems. We consider cases in which the jump of a field across the interface is given, as well as cases in which the primary field on the interface is given. The finite element mesh need not be aligned with the interface geometry. We present closed‐form analytical expressions for interfacial stabilization terms and simple procedures for accurate flux evaluations. Representative numerical examples demonstrate the effectiveness of the proposed methodology. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
104.
105.
106.
Dick R 《Nanoscale research letters》2010,5(10):1546-1554
We consider electrons in the presence of interfaces with different effective electron mass, and electromagnetic fields in
the presence of a high-permittivity interface in bulk material. The equations of motion for these dimensionally hybrid systems
yield analytic expressions for Green’s functions and electromagnetic potentials that interpolate between the two-dimensional
logarithmic potential at short distance, and the three-dimensional r
−1 potential at large distance. This also yields results for electron densities of states which interpolate between the well-known
two-dimensional and three-dimensional formulas. The transition length scales for interfaces of thickness L are found to be of order Lm/2m
* for an interface in which electrons move with effective mass m
*, and Le*/2eL\epsilon_\ast/2\epsilon for a dielectric thin film with permittivity e*\epsilon_\ast in a bulk of permittivity e\epsilon. We can easily test the merits of the formalism by comparing the calculated electromagnetic potential with the infinite series
solutions from image charges. This confirms that the dimensionally hybrid models are excellent approximations for distances
r ≳ L/2. 相似文献
107.
Understanding large, complex networks is important for many critical tasks, including decision making, process optimization, and threat detection. Existing network analysis tools often lack intuitive interfaces to support the exploration of large scale data. We present a visual recommendation system to help guide users during navigation of network data. Collaborative filtering, similarity metrics, and relative importance are used to generate recommendations of potentially significant nodes for users to explore. In addition, graph layout and node visibility are adjusted in real‐time to accommodate recommendation display and to reduce visual clutter. Case studies are presented to show how our design can improve network exploration. 相似文献
108.
109.
M.L. Zheludkevich S.K. Poznyak D. Raps L.F. Dick M.G.S. Ferreira 《Corrosion Science》2010,52(2):602-1918
Novel LDH-based nanocontainers of corrosion inhibitor are developed in the present work. The reservoirs are composed by nanostructured layered double Mg/Al and Zn/Al hydroxides with divanadate anions located in the interlayer regions. The nanocrystalline LDHs (layered double hydroxides) are able to release vanadate ions in a controllable way.XRD, EDS and SEM methods were used in this work to study morphological and structural properties of the synthesized LDH powders. Corrosion protection effect of the LDH powders directly added to corrosive electrolyte or to commercial coatings used for aeronautical application has been studied by electrochemical impedance spectroscopy and standard accelerated corrosion tests. Aluminium alloy 2024 was used here as substrate.The results demonstrate that both of the LDH pigments being added to corrosive media confer corrosion inhibition effect, especially Zn/Al based nanocontainers obtained by the anion-exchange approach. The coatings doped with Zn/Al LDH-nanocontainers provide well-defined self-healing effect and confer corrosion protection properties superior than currently used environmentally unfriendly chromate-based systems. 相似文献
110.
María Dolores Ayala Isaac Abdel Carmen Martínez Francisco Gil Octavio López Albors 《LWT》2010,43(3):465-17
Sea bream, Sparus aurata L., specimens were studied in pre-rigor (3 h) and during the following post-mortem days: 1, 5, 10, 15 and 22. Muscle and textural parameters were evaluated on 6 specimens/stage. Structural results showed scarce fibre-to-fibre detachment on pre-rigor, which increased during the post-mortem degradation. Ultrastructural changes revealed rapid muscle degradation. In pre-rigor myofibrils were detached to both sarcolemma and endomysium. Intermyofibrillar spaces increased and some mitochondriae and sarcoplasmic reticulum were swollen. After 1 day, the sarcolemma appeared occasionally disrupted and the interfibrillar spaces increased. From 5 to 10 days, the I-band and Z line presented some alterations, although these were more severe at 15-22 days. Thus, in these two last stages, loss of I-band, Z line and actin filaments was observed, that coincides with the alteration of the hexagonal arrangement in these advanced stages. Also, the fragmentation of myofibrils increased from 5 to 10 days on. Sarcolemma and endomysium were gradually disrupted throughout the post-mortem stages with total loss at 22 days. Consequently, the interfibrillar spaces increased at last stages. Autophagic mechanisms increased from 5 days on, with an intense destruction of all the intracytoplasmic organelles. Textural parameters decreased from pre-rigor until 5-10 days, mainly associated to detachment of myofibers to sarcolemma-endomysium. 相似文献