Search results for "Ultima"
showing 10 items of 396 documents
Comparison of the effect of different surface treatments on the bond strength of different cements with nickel chromium metal alloy: An in vitro study
2017
Background For success of any indirect metal restoration, a strong bond between cement and the intaglio surface of metal is imperative. The aim of this study is to evaluate and compare the effect of different surface treatment on the tensile and shear bond strength of different cements with nickel–chromium alloy. Material and Methods 120 premolars were sectioned horizontally parallel to the occlusal surface to expose the dentin. Wax patterns were fabricated for individual tooth followed by casting them in nickel chromium alloy. 60 samples were tested for tensile bond strength, and the remaining 60 for shear bond strength. The samples were divided into three groups (of 20 samples each) as pe…
Experimental investigation on the effect of mortar grade on the compressive behaviour of FRCM confined masonry columns
2018
Abstract The use of Fiber Reinforced Cementitious Mortar (FRCM) systems for structural retrofitting of masonry structures has become increasingly popular in the last years, due to the capability of this technique in overcoming some of the drawbacks related to the adoption of resin-based composites. Recent studies investigated on the effect of FRCM wraps on the compressive behaviour of concrete members and demonstrated as the application of mortar-based composites allows increasing the strength and, above all, the ductility of the column. The main difference with FRP confined columns is related to the different post-peak behaviour, characterized by a softening branch. Differently, few studie…
Effect of areal weight and chemical treatment on the mechanical properties of bidirectional flax fabrics reinforced composites
2010
Abstract In this paper several bidirectional flax fibers, usually used to made curtains, were employed as reinforcement of an epoxy matrix. Four different laminates were made by a vacuum bagging process, with varying both the areal weight and the treatment of the fabric. These structures were mechanically investigated carrying out both tensile and three point flexural tests. In order to evaluate the effect of the identified variables on the mechanical parameters (i.e. Young modulus and maximum stress) a statistical analysis was performed. Finally, by comparing the flax composite with a glass one, the convenience of the replacement of glass fiber was investigated in term of cost, weight and …
Minimal intervention in dentistry: Which is the best approach for silorane composite restoration repairs?
2021
Made available in DSpace on 2021-06-25T10:28:11Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-04-01 Background: This study aimed to evaluate surface treatments, adhesives and composites for repairing silorane based restorations. Material and Methods: One hundred and twenty truncated cones (2 mm smaller diameter and 4 mm larger diameter) made of silorane composite were divided in 12 groups according with the surface treatment (diamond bur and oxide aluminum abrasion), the adhesive (Adper Scothbond Multipurpose (3M ESPE), Ecusit (Voco) and Filtek P90 Adhesive (3M ESPE)). Each group was subdivided in two according with the composite used for repair (methacrylate and silorane). The rep…
Mechanical properties of steel fibre reinforced lightweight concrete with pumice stone or expanded clay aggregates
2001
This paper presents basic information on the mechanical properties of steel fibre-reinforced light-weight concrete, manufactured using pumice stone or expanded clay aggregates. Results are presented for standard compressive tests and indirect tensile tests (splitting tests on cylinder specimens and flexure tests on prismatic beams using a three-point loading arrangement) under monotonically increasing or cyclically varying loads. The influence of steel fibres and aggregate types on modulus of elasticity, compressive and tensile strength and post-peak behaviour is evaluated. Test results show that compressive strength does not change for pumice stone aggregates, while an increase is observed…
Effect of Nanodiamonds on Structure and Durability of Polyethylene Oxide-Based Nanocomposites
2016
Polymer-based nanocomposites containing nanodiamonds (NDs) are attractive multifunctional materials with a growing range of applications. In this work, in the frame of developing completely biocompatible systems, nanocomposites based on polyethylene oxide (PEO) and different amount of NDs have been formulated through melt mixing and fully characterized. In particular, the reinforcement effect of NDs in PEO has been probed through tensile tests, and the rheological response of PEO-based nanocomposites as a function of the nanoparticles amount has been investigated and discussed. The obtained results show that the presence of well-distributed NDs strengthens the mechanical performance of the …
Properties-morphology relationships in electrospun mats based on polylactic acid and graphene nanoplatelets
2018
Abstract Aligned and randomly oriented polylactic acid (PLA) biocomposite nanofiber mats filled with Graphene nanoplatelets (GnP) were prepared by electrospinning. The morphological analysis revealed the successful alignment of the fibers achieved by collecting the mats on a high-speed rotary drum. Furthermore, GnP addition on the polymeric solution leads to an increase of the viscosity with a consequent increment of the fiber diameter. Tensile tests demonstrated that the reinforcing effect of GnP when added to the PLA matrix was more than three times higher in the aligned systems if compared with the respective randomly oriented mats. DSC analysis showed that GnPs were able to slightly inc…
Experimental Comparison of the MIG and Friction Stir Welding Processes for AA 6005 Aluminium Alloy
2015
In this study, the mechanical properties of welded joints of AA 6005 aluminum alloy obtained with friction stir welding (FSW) and conventional metal inert gas welding (MIG) are studied. FSW welds were carried out on a semi-automatic milling machine. The performance of FSW and MIG welded joints were identified using tensile and bending impact tests, as far as the environmental aspects are also included in the discussion. The joints obtained with FSW and MIG processes were also investigated in their microstructure. The results indicate that, the microstructure of the friction stir weld is different from that of MIG welded joint. The weld nugget consists of small grains in FSW than those found…
Compressive behaviour of laminated structural glass members
2011
Abstract Several experimental investigations in the past few years have highlighted the fact that the compressive strength of glass was significantly higher than its tensile strength, allowing new applications of glass in compression members. However, due to the high slenderness of structural glass elements made of thin glass panels, they tend to fail in a brittle manner. A substantial amount of fundamental research has been carried out in the past few years to investigate the stability behaviour of structural glass elements. However, although buckling of glass panels has been quite well studied, a very poor amount of research has been addressed to glass columns, which by contrast represent…
Mechanical characterization of rose bengal and green light crosslinked collagen scaffolds for regenerative medicine
2021
Abstract Collagen is one of the most important biomaterials for tissue engineering approaches. Despite its excellent biocompatibility, it shows the non-negligible disadvantage of poor mechanical stability. Photochemical crosslinking with rose bengal and green light (RGX) is an appropriate method to improve this property. The development of collagen laminates is helpful for further adjustment of the mechanical properties as well as the controlled release of incorporated substances. In this study, we investigate the impact of crosslinking and layering of two different collagen scaffolds on the swelling behavior and mechanical behavior in micro tensile tests to obtain information on its wearin…