Search results for "Steel"
showing 10 items of 338 documents
A new design problem in the formulation of a special moment resisting connection device for preventing local buckling
2021
In the present paper an improved formulation devoted to the optimal design problem of a special moment resisting connection device for steel frames is proposed. This innovative device is called a Limited Resistance Plastic Device (LRPD) and it has been recently proposed and patented by some of the authors. It is thought to be preferably located at the extremes of the beam, connecting the beam end cross section with the relevant column. The typical device is a steel element characterized by symmetry with respect to three orthogonal barycentric planes and constituted by a sequence of three portions with abrupt cross section changes. The main novelty of the present proposal is related to the d…
Study of interface formation during diffusion bonding : compact heat exchangers application
2014
Compact diffusion bonded heat exchangers are an attractive option in many fields (nuclear, (petro-)chemistry, solar…) due to their performance. This type of concept is especially intended for manufacturing the energy conversion system of the ASTRID reactor. During diffusion bonding by HIP, the problem is twofold: the channel deformation and microstructure evolution must be controlled, while at the same time, highly resistant interfaces are desired. This thesis is focused on the understanding and the control of the bonded components microstructure prepared by HIP in order to define « process » criteria to achieve welds in agreement with specifications of components containing fluidic channel…
Galvanic deposition of Hydroxyapatite/Chitosan/Collagen coatings on 304 stainless steel
2021
The galvanic deposition method was used to deposit Hydroxyapatite/Chitosan/Collagen coatings on 304 stainless steel. Galvanic deposition is an alternative and valid way to fabricate bio-coatings with high biocompatibility and good anticorrosion properties. Physical-chemical characterizations were carried out to investigate chemical composition and morphology of the samples. Coatings consist of a mixture of calcium phosphate (Brushite and Hydroxyapatite) with chitosan and collagen. Corrosion tests were performed in the simulated body fluid (SBF) after different aging times. Results show that, in comparison with bare 304 stainless steel, coating shifts corrosion potential to anodic values and…
Atmospheric Corrosion Investigation in Industrial, Marine and Rural Environments in South-East Brazil
2002
ASTM 283-C, AISI 304 and 316-L steel specimens (called coupons) were exposed in marine, industrial and rural area(s) for different periods ranging between 1–12 months, in four different season campaigns. The corrosion rate was determined by chemical loss measurements. Rust characterization was performed by XRD, SEM, optical, and Mossbauer spectroscopy (in transmission and backscattering geometry). Superparamagnetic maghemite and goethite were found as corrosion products. Magnetic goethite and feroxyhite decrease with time of exposure. Lepidochrosite is detected and its intensity increase with the atmospheric exposure time. The results obtained from XRD and Mossbauer are in good agreement.
Effect of steel collars on the seismic behaviour of granite and heavy stone columns
2013
Granite and heavy stone circular columns could be often find in the cultural heritage among ancient churches and historical buildings in all the Mediterranean area. Their good strength properties allowed to carry great load values, while their bright colours and aesthetical characteristics have been used by a lot of ancient architects to achieve structural solutions with great visual impact. Even if such materials have great compressive strength values, the environmental effects, such as long term effects and thermal loads, could damage the structural members, by cracking them. In this way the slenderness of the column increases, and the presence of an imposed ground motion could be very da…
Tuntemusten paikkansapitävyys tiellä ja maastossa juniori- ja miessuunnistajilla
2008
Suomalaisessa kestävyysvalmennuksessa sekä nuorten että vanhempien urheilijoidenosalta harjoittelu tapahtuu usein urheilijan omiin suorituksen aikaisiin tuntemuksiinperustuen. Kuitenkin on olemassa hyvin vähän tietoa, vastaako tuntemuksien mukaanharjoittelu kulloinkin tavoitteena olevia todellisia harjoitusvauhteja. Tämän tutkimuksentarkoitus on selvittää osaavatko mies- ja poikasuunnistajat juosta tuntemuksienperusteella tavoitteena olevalla sykealueella tiellä ja maastossa.Tutkimukseen osallistui 13 koehenkilöä, jotka kuuluivat miesten (n=6) ja poikien (n=7)ryhmiin. Iältään koehenkilöt jakautuivat yli ja alle 20-vuotiaisiin. Kaikki koehenkilötsuorittivat tutkimuksen alussa 2,8 km:n arvioj…
Mechanical characterization of bio-based composite/metal laminates for an application in street furniture
2019
In this work, it is proposed to study the influence of three manufacturing parameters in the development of bio-basedcomposite/steel hybrids. These parameters arethe methodof assembly between composite and metal, the distribution of composite and steellayers throughthe thicknessof the hybrid,and the stacking sequence of the composite part of the hybrid. The study was conducted through impact tests at different energies and quasi-static three-point bending tests. For each of these parameters, the influenceon the mechanical properties of the hybrid is evaluated.The results show that these properties depend essentially on the relative distribution of steel and composite through the thickness.
Galvanic Deposition of Hydroxyapatite/Chitosan/Collagen Coatings on 304 Stainless Steel
2021
The galvanic deposition method was used to deposit Hydroxyapatite/Chitosan/Collagen coatings on 304 stainless steel. Galvanic deposition is an alternative and valid way to fabricate bio-coatings with high biocompatibility and good anticorrosion properties. Physical-chemical characterizations were carried out to investigate chemical composition and morphology of the samples. Coatings consist of a mixture of calcium phosphate (Brushite and Hydroxyapatite) with chitosan and collagen. Corrosion tests were performed in the simulated body fluid (SBF) after different aging times. Results show that, in comparison with bare 304 stainless steel, coating shifts corrosion potential to anodic values and…
Improved antifouling properties and selective biofunctionalization of stainless steel by employing heterobifunctional silane-polyethylene glycol over…
2016
AbstractA straightforward solution-based method to modify the biofunctionality of stainless steel (SS) using heterobifunctional silane-polyethylene glycol (silane-PEG) overlayers is reported. Reduced nonspecific biofouling of both proteins and bacteria onto SS and further selective biofunctionalization of the modified surface were achieved. According to photoelectron spectroscopy analyses, the silane-PEGs formed less than 10 Å thick overlayers with close to 90% surface coverage and reproducible chemical compositions. Consequently, the surfaces also became more hydrophilic, and the observed non-specific biofouling of proteins was reduced by approximately 70%. In addition, the attachment of E…
QUALITY COMPETITIVENESS OF LATVIA’S METAL INDUSTRY IN THE IRON AND STEEL PRODUCT GROUPS
2012
The aim of this paper is to develop framework for evaluation of quality competitiveness of countries exports and to use this framework to examine quality competitiveness of Latvia’s metal industry in the iron and steel product groups. To achieve this aim authors studied topic related scientific literature and used appropriate methods to examine quality competitiveness according to the other researchers and authors own developed approach. To successfully achieve the aim of the paper and fulfill the tasks set the following research methods were used: 1) monographs method; 2) logical - constructive; 3) statistical analysis techniques: structural analysis and regression analysis; 4) graphical m…