Search results for " steel"
showing 10 items of 244 documents
Numerical validation of LRPH behaviour by FEM analysis
2019
LRPH connection is a special steel device mainly usable to join beam elements of plane or spatial steel frames. It is identified as Limited Resistance Rigid Perfectly Plastic Hinge and it is covered by patent n. 102017000088597 at the Italian Ministry of Economic Development and identified in the International Patent System with the number PCT/IB2018/055766. The fundamental innovations of this device are the mutual independence of their own resistance and stiffness features and the respect of assigned constraints related to the elastic and limit behavior of the joined elements. Within the frame structural scheme, the device plays the role of a rigid perfectly plastic hinge, and it is consti…
Identification of optimal device combinations for the chimney endovascular aneurysm repair technique within the PERICLES registry
2018
Abstract Objective The ideal stent combination for chimney endovascular aneurysm repair remains undetermined. Therefore, we sought to identify optimal aortic and chimney stent combinations that are associated with the best outcomes by analyzing the worldwide collected experience in the PERformance of chImney technique for the treatment of Complex aortic pathoLogiES (PERICLES) registry. Methods The PERICLES registry was reviewed for patients with pararenal aortic disease electively treated from 2008 to 2014. Eleven different aortic devices were identified with three distinct subgroups: group A (n = 224), nitinol/polyester; group B (n = 105), stainless steel/polyester; and group C (n = 69), n…
Toxicity of used orthodontic archwires assessed by three-dimensional cell culture
2006
The aim of the present study was to determine whether used orthodontic wires made of different materials cause toxicity and loss of viability on three-dimensional (3D) cell cultures. Three types of orthodontic wires, stainless steel, Nitinol, and TMA (n = 9) which had been used clinically in fixed appliances for a period of 1 month, were retrieved at random from five patients. Both upper and lower archwires were collected and subjected to two different protocols: to assess toxicity, two pieces of each wire were placed on 3D cell cultures (reconstituted human epithelium); to investigate the possibility of cell damage, the 3-(4,5-dimethylthiazol-2-yl)2,5-diphenyl tetrazolium bromide (MTT) ass…
Increasing the shear capacity of reinforced concrete beams using pretensioned stainless steel ribbons
2017
In this work, the second part of an experimental campaign investigating the efficiency of an alternative retrofitting method for increasing the flexural and/or shear capacity in reinforced concrete beams, based on the use of prestressed stainless steel ribbons and steel angles, is presented and analytically reproduced. This group of tests focuses on the ability of the adopted retrofitting method to improve the shear strength and ultimate deformation of reinforced concrete structural elements. As described in a companion paper, the adopted retrofitting method is alternative to traditional techniques of reinforced concrete retrofitting, being easy to install and usually reversible, and charac…
Stress transfer and failure mechanisms in steel-concrete trussed beams: Experimental investigation on slab-thick and full-thick beams
2018
Abstract This study presents the results of an experimental investigation on semi-precast Hybrid Steel Trussed-Concrete Beams (HSTCBs) for analyzing the failure modes and the stress transfer mechanism between concrete and embedded steel elements (plate and truss). The available literature presents previous studies carried out by the authors mainly focused on the understanding of the local transfer mechanism by means of push-out tests. Conversely, in this paper original the results of laboratory tests conducted on six specimens of full-size HSTCBs subjected to four-point bending, with variation in the shear span, are reported on. From these results, the authors are able to assess the failure…
One-step electrodeposition of superhydrophobic coating on 316L stainless steel
2021
Superhydrophobic coatings were fabricated through a one-step electrochemical process onto the surface of 316L stainless steel samples. The presence of hierarchical structures at micro/nanoscale and manganese stearate into the coatings gave superhydrophobicity to the coating, with contact angle of ~160°, and self-cleaning ability. Corrosion resistance of 316L samples was also assessed also after the electrodeposition process through Electrochemical Impedance Spectra recorded in an aqueous solution mimicking seawater condition.
Wavelet and fractal approach to surface roughness characterization after finish turning of different workpiece materials
2009
In this paper, the surface profiles generated in longitudinal turning operations were characterized using continuous wavelet transform (CWT) and normalized fractal dimension Dn. In the comparative analysis, some characteristic roughness profiles after the turning of different workpiece materials, such as C45 medium carbon steel, nodular cast iron and hardened (55 HRC) high-strength alloy steel were selected. For wavelet characterization, both Morlet and ‘Mexican hat’ analyzing wavelets, which allow the assessment of extrema and frequency distribution, were utilized. The results of the CWT as a function of profile and momentary wavelet length are presented. It is concluded that CWT can be us…
Defects in Martensitic Stainless Steel 1.4031 (EN) Exposed to Friction as Seen by Positron Annihilation
2010
We present experimental results of measurements of the Doppler broadening of annihilation line and positron annihilation lifetimes in martensitic stainless steel 1.4031 (EN) samples exposed to the dry sliding under different loads. In particular, we tested the subsurface zone under the worn surfaces. As a main result, we obtained information about the defect profiles in this zone and the total extent of the damage region induced by the dry sliding.
Effect of NaClO disinfection/cleaning on passive films on AISI 316L
2020
Abstract 316 L stainless steel samples were passivated in NaClO containing solutions in order to simulate disinfection processes. Passive films were grown at the open circuit potential by immersion in NaClO aqueous solutions at different concentrations and temperature in order to understand how exposure to aggressive environments could affect subsequent corrosion resistance of SSs. In the attempt to study the passive film growth mechanism, in-situ Open Circuit Potential measurements were performed in the same growth solutions. Photoelectrochemical and impedance investigation of passive films was carried out in order to link their solid state properties with their corrosion behaviour.
Photoelectrochemical monitoring of rouging and de-rouging on AISI 316L
2017
Electrochemical conditions for inducing rouging on surface of AISI 316L in quasi neutral aqueous solution are studied. Potentiostatic polarization at 0.6 V vs. SSC at pH ∼ 7 allowed growth of colourless passive films with a band gap slightly lower than that estimated for the oxide grown on the SS surface by air exposure due to chromium dissolution. Under stronger anodic polarization (UE = 1.5 V vs. SSC) coloured passive films are formed, mainly constituted by iron oxide according to their band gap (Eg = 2.0 eV). Etching in citric acid at 60 °C results to be effective in removing rouging.