Search results for "LOAD"
showing 10 items of 1967 documents
Mechanical behavior of provisional implant prosthetic abutments
2014
Introduction: Implant-supported prostheses have to overcome a major difficulty presented by the morphology and esthetics of peri-implant tissues in the anterior sector. Diverse therapeutic techniques are used for managing the mucosa adjacent to the implant and the most noteworthy is immediate/deferred fixed provisionalization. Objectives: In vitro testing of strength and deformation of implant prosthetic abutments made from different materials (Titanium/PEEK/methacrylate). Material and Methods: Forty Sweden&Martina® implant prosthetic abutments (n=40) were divided into five groups: Group MP: methacrylate provisional abutments with machined titanium base; Group PP: Poly ether ether ketone (P…
Pumice concrete for structural wall panels
2003
Some properties of lightweight pumice stone concrete (LWPSC) are discussed, on account of a possible structural use of this material. Then the results of an experimental investigation are described, in order to show that pumice can really be considered an alternative to common artificial lightweight aggregates, taking into account the performance pointed out by loading tests carried out on structural systems made of LWPSC. Three different kinds of reinforced wall panels were made using LWPSC, lightweight expanded clay concrete and normal weight concrete; then their structural responses under horizontal cyclic and constant vertical forces were compared, above all with reference to lateral st…
Mesenchymal stem cell proliferation and differentiation on load-bearing trabecular Nitinol scaffolds.
2013
Bone tissue regeneration in load-bearing regions of the body requires high-strength porous scaffolds capable of supporting angiogenesis and osteogenesis. 70% porous Nitinol (NiTi) scaffolds with a regular 3-D architecture resembling trabecular bone were produced from Ni foams using an original reactive vapor infiltration technique. The "trabecular Nitinol" scaffolds possessed a high compressive strength of 79 MPa and high permeability of 6.9×10(-6) cm2. The scaffolds were further modified to produce a near Ni-free surface layer and evaluated in terms of Ni ion release and human mesenchymal stem cell (hMSC) proliferation (AlamarBlue), differentiation (alkaline phosphatase activity, ALP) and …
Moment-axial force domain of corroded R.C. columns
2016
In the present paper, a simple model to determine the moment-axial force domain of the cross-section of reinforced concrete (R.C.) columns subjected to corrosion process is presented. The model considers members with square and rectangular cross-sections and it accounts for—cover spalling; buckling of longitudinal reinforcing bars; loss of bond of bar in tension; reduction of confinement pressures (due to the reduction of the area of stirrups and cracking of concrete induced by rust formation). The analytical expressions for prediction of the area reduction of steel, bond strength and critical load of longitudinal bars utilized were verified against experimental data available in the litera…
Oil whip-induced wear in journal bearings
2014
Published version of an article in the journal: International Journal of Advanced Manufacturing Technology. Also available from the publisher at: http://dx.doi.org/10.1007/s00170-014-5805-8 This paper investigates the effect of oil whirl and oil whip in fluid film radial bearings due to possible metallic contact. The degree of metallic contact and thereby wear and tear between rotating shafts and bearing bushes is assessed by measuring electric currents through the oil film. The current as well as the voltage varied in accordance with the contact ratio between the shaft and bush in the fluid film radial bearing. The gauge signal thus indicates the degree of metallic contact based on the thi…
Hybrid catalysts for CO 2 conversion into cyclic carbonates
2019
The conversion of carbon dioxide into valuable chemicals such as cyclic carbonates is an appealing topic for the scientific community due to the possibility of valorizing waste into an inexpensive, available, nontoxic, and renewable carbon feedstock. In this regard, last-generation heterogeneous catalysts are of great interest owing to their high catalytic activity, robustness, and easy recovery and recycling. In the present review, recent advances on CO 2 cycloaddition to epoxide mediated by hybrid catalysts through organometallic or organo-catalytic species supported onto silica-, nanocarbon-, and metal-organic framework (MOF)-based heterogeneous materials, are highlighted and discussed.
Frictional effect in mode II delamination: Experimental test and numerical simulation
2013
Abstract The present paper proposes an experimental and a numerical analysis of the frictional effect on the mode II delamination. Frictional stresses between the crack edges can absorb and dissipate significant energy contributions in the delamination zones, especially under cyclic loading conditions. The experimental tests are performed for a set of unidirectional End-Notched Flexure (ENF) composite specimens, which are subjected to fatigue loading law with increasing mean value. The numerical analyses are performed considering a cohesive–frictional constitutive model, which is able to reproduce the transition of the interface behavior from the sound elastic condition to the fully cracked…
A strategy for the finite element modeling of FRP-confined concrete columns subjected to preload
2018
Abstract Compressive behavior of columns strengthened by means of an outer elastic confinement provided e.g. by fiber-reinforced polymer (FRP) jackets has become a main topic in the field of structural retrofitting. In details, the problem of the response assessment of strengthened columns is still under study. Many analytical formulations have been proposed to describe the compressive behavior of confined concrete under both monotonic and cyclic loads. However, the effect of a stress/strain level in the columns already present prior to apply the confinement has been generally neglected until now, also because of the lack of well defined strategies of modeling. In this frame, here, (1) a FE…
Laminated Glass Members in Compression: Experiments and Modeling
2014
It is well known that structural glass members are made by assembling thin laminated panels, which can be connected with different bonding techniques; for instance, with steel devices or with structural adhesives. The latter are very commonly used because they do not reduce the transparency of the member and make it possible to avoid stress concentrations because of the presence of holes. This technique is used to make up columns in glazing structures and different applications of the technique can be found in contemporary architecture. As evidenced by the literature, one of the most important problems in such members is caused by buckling phenomena, resulting from the slenderness of the pa…
Effect of framework type on survival probability of implant-supported temporary crowns : an in vitro study
2020
Made available in DSpace on 2020-12-12T01:29:18Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-01-01 Background: This in vitro study evaluated the effect of framework type on the survival probability of temporary implant-supported crowns and on the implant platform structure after dynamic fatigue. Material and Methods: Thirty (30) external hexagon implants (3.75 x 10 mm) were embedded in acrylic resin following the ISO-14801. Standardized temporary crowns (n=10, N=30) were manufactured in acrylic resin and divided according to the framework type: Total plastic, Plastic with CoCr base and Titanium. The crowns were installed onto the implants (20N. cm) and fatigued (100N, 2 Hz) to det…