Search results for "Steel"
showing 10 items of 338 documents
The use of steel angles for the connection of laminated glass beams: Experiments and modelling
2012
Abstract In the present paper the experimental results relative to three-point bending tests on multilayer glass beams and on semi-rigid connections realised with stainless double web angles are presented and discussed. Small and medium size glass beams were tested and load–deflection curves and crack patterns at failure were recorded. The laminated glass specimens, of equal cross-section, were characterised by three different combinations of annealed float and fully thermally tempered glass plies and different interlayers. Steel joints constituted by double web angles to connect two glass beams were tested adopting several geometrical configurations and using stainless steel bolts preloade…
BiZact tonsilektomijas un konvencionālās tonsilektomijas metožu salīdzinājums
2022
Paskaidrojošā informācija: Tonsilektomija ir viena no visbiežāk veiktajām ķirurģiskajām operācijām cilvēces vēsturē. Tonsilektomija tehnoloģijas un procedūras gadu gaitā ir attīstījušās, lai uzlabotu pacientu aprūpi saistībā ar intraoperācijas un pēcoperācijas riskiem. Mērķis: Šī pētījuma mērķis ir salīdzināt BiZact tonsilektomijas metodi ar tradicionālo «aukstās pieejas» tērauda tonsilektomijas metodi attiecībā uz ķirurģiskajiem rezultātiem. Nolūks: Klasiskā «aukstās pieejas» tērauda tonsilektomijas metode ir viena no visbiežāk izmantotajām metodēm, un tā ir balstīta uz tonsilektomijas instrumentiem, jo ar tiem ir viegli strādāt, tiem nav nepieciešama elektrība (un līdz ar to tie ir vienkā…
Steel-concrete bond in lightweight fiber reinforced concrete under monotonic and cyclic actions
2005
Experimental results of the local bond stress-slip relationship of reinforcing bars embedded in lightweight fiber reinforced concrete with expanded clay aggregates are presented. The effect of the following parameters were investigated: - dimension of specimens; - anchorage length; - percentages of hooked steel fibers; - geometrical ratio of transverse reinforcement; - confinement external transverse pressure. Prismatic specimens with deformed steel bars embedded for a fixed length equal to five and eight equivalent diameters were tested under both monotonic and cyclic reversal imposed displacements at the tip of the bars, in controlled displacement tests. The influence of the above mention…
Simplified technique for constitutive analysis of SFRC
2014
Steel fibre reinforced concrete (SFRC) has become widespread material in areas such as underground shotcrete structures and industrial floors. However, due to the absence of material models of SFRC reliable for numerical analysis, application fields of this material are still limited. Due to interaction of concrete with fibres, a cracked section is able to carry a significant portion of tensile stresses, called the residual stresses. In present practices, residual stresses used for strength, deflection and crack width analysis are quantified by means of standard tests. However, interpretation of these test results is based on approximation using empirically deduced relationships, adequacy o…
Effect of temperature on the passive state of Alloy 31 in a LiBr solution: Passivation and Mott-Schottky analysis
2015
The passive behaviour of Alloy 31, a highly-alloyed austenitic stainless steel (UNS N08031), has been investigated in a LiBr heavy brine (700 g/l) at different temperatures using potentiostatic polarisation and Mott-Schottky analysis. Cation vacancies have been found to be the dominant defect in the passive films formed on Alloy 31. An increase in temperature enhanced the generation of cation vacancies at the film/solution interface and raised the steady-state passive current density. The density of defects within the passive film also increased significantly with temperature, making the film more conductive and less protective against localised attacks.
Reliability of numerical models for simulating galvanic corrosion processes
2012
International audience; Maturity of numerical simulation represents an important issue in the development of predictive models of galvanic corrosion. As widely used in electrochemical engineering, a coupled electrochemical-transport-reaction (CETR) model is recommended to simulate the current distribution above a galvanic corrosion cell made of the cut-edge of a galvanized steel sheet. Nevertheless, simulating current density distributions obtained experimentally by scanning vibrating electrode technique (SVET) above such a galvanic cell appears to be more accurate using an electrostatic model considering a homogeneous conductivity. In this case, the absence of concentration gradients next …
Galvanic deposition and characterization of brushite/hydroxyapatite coatings on 316L stainless steel
2016
In this work, brushite and brushite/hydroxyapatite (BS, CaHPO4·H2O; HA, Ca10(PO4)6(OH)2) coatings were deposited on 316L stainless steel (316LSS) from a solution containing Ca(NO3)2·4H2O and NH4H2PO4 by a displacement reaction based on a galvanic contact, where zinc acts as sacrificial anode. Driving force for the cementation reaction arises from the difference in the electrochemical standard potentials of two different metallic materials (316LSS and Zn) immersed in an electrolyte, so forming a galvanic contact leading to the deposition of BS/HA on nobler metal. We found that temperature and deposition time affect coating features (morphology, structure, and composition). Deposits were char…
Retrofitting of Existing Steel MR-Frames by Encasing the Columns
2005
Summary The study concerns the behaviour of steel MR-frames subjected to vertical and lateral forces, not properly designed according to capacity design criteria, and upgraded by means of encasing the steel columns with concrete having different grade. The purpose of the paper is to examine if the proposed technique allows one to adequately increase the lateral stiffness and the resistance of the frames. Pushover analyses on multi-storey frames are performed trough a non-linear calculus program, able to take into account of the second order effects. The behaviour of frames with encased columns was compared with those of the bare frames, highlighting that with the proposed technique it is po…
In-situ radiotracer studies of sorption processes in solutions containing (bi)sulfite ions—II. Low carbon steel
1997
Abstract In this paper, time, potential and pH dependence of SO42− and HSO3− accumulations measured by an in-situ radiotracer method on surface oxide layers of low carbon steel are presented and discussed. This work is a continuation of a research program[1–5] and deals with the characterization of the sorption behaviour of low carbon steel in solutions containing sulfate and bisulfite ions (as a possible model of acid rain). From the experimental results it can be stated that 1. (i) the presence of bisulfite ions in the solution phase accelerates the corrosion of low carbon steel; 2. (ii) at E > 0.40 V the electrooxidation of HSO3− ions presumably proceeds to yield a steel surface covered …
Inhibitoren der Korrosion 24 (1) - Zur Vergleichbarkeit der Abhängigkeit der Korrosion und Korrosionsinhibierung von der Chloridionen- und Inhibitork…
1979
Die Abhangigkeit der „unter Standardbedingungen” im Schuttelversuch ohne und mit Inhibitoren ermittelten O2-Aufnahmegeschwindigkeit von der Chloridionenkonzentration und der Menge an Eisenpulver wird ermittelt. Ergebnis: die von uns bisher eingehaltenen Standardbedingungen vermitteln an Hand der Schutz werte ein qualitativ verlasliches Bild uber die Inhibitorwirksamkeit. Die Vergleichbarkeit der im Schuttelversuch mit DAB 6-Eisenpulver ermittelten Werte mit den im Schuttelversuch mit 1405-Stahlblechen gefundenen Werten wird durch Versuche mit 1405-Stahlblechraspel abgesichert. Die Korrosionsrate phosphatisierter Stahlbleche 1405 wird durch Inhibitoren mit Phosphonsauregruppen wirksam unterd…