Structural integrity analysis of notched ferritic steels operating within their ductile-to-brittle transition zone: An approach from Failure Assessment Diagrams and the Notch Master Curve

This paper provides a structural integrity assessment methodology for the analysis of ferritic steels containing notch-type defects and operating within their ductile-to-brittle transition zone. The methodology, based on the use of Failure Assessment Diagrams and the novel concept of the Notch Master Curve, has been applied to 323 experimental results performed on four different steels (S275JR, S355J2, S460M and S690Q), six different notch radii (from 0 mm up to 2.0 mm), two different types of specimens (CT and SENB), and three different temperatures within the corresponding ductile-to-brittle transition zone. The results validate the proposed assessment methodology

The Notch Master Curve: A proposal of Master Curve for ferritic–pearlitic steels in notched conditions

This paper presents a model for the prediction of the apparent fracture toughness of ferritic–pearlitic steels in notched conditions and operating at temperatures corresponding to their ductile-to-brittle transition zone. The model, here named the Notch-Master Curve, is based on the combination of the Master Curve of the material in cracked conditions and the notch corrections provided by the Theory of Critical Distances. In order to validate the model, the fracture resistance results obtained in 168 tests performed on CT specimens (84 for each material) are presented. These tests were carried out, for each material, in specimens with six different notch radii, from 0 mm up to 2.0 mm, and at three different temperatures within their corresponding ductile-to-brittle transition zone. It has been observed that the model provides good predictions of the fracture resistance in notched conditions for the two materials analysed

INCEFA-PLUS Programme Overview and Update

INCEFA-PLUS is a five year project supported by the European Commission HORIZON2020 programme which commenced in mid 2015. 16 organisations from across Europe have combined forces to deliver new experimental data and a fatigue assessment procedure which will support the development of improved guidelines for assessment of environmental fatigue damage to ensure safe operation of nuclear power plants. Prior to the start of INCEFA-PLUS, an in-kind study was undertaken by several European organisations with the aim of developing the current state of the art for this technical area. This study identified three experimental variables which required further study in order to support improved assessment methodology for environmental fatigue, namely the effects of mean stress/strain, hold time and surface finish. Within INCEFA-PLUS, the effects of these three variables, plus strain amplitude, on fatigue endurance of austenitic stainless steels in light water reactor environments are therefore being studied experimentally. The data obtained will be collected and standardised in an online environmental fatigue database. In order to facilitate the exchange of fatigue data a standardized data format will be developed in the framework of a CEN workshop, to which international participants are welcome to participate. The outcome of the workshop will be a pre-normative document, a CEN Workshop Agreement (CWA) which will set a standard for enabling the exchange of fatigue data not only within the project but within the fatigue community. Based on the data generated and the resulting improvement in understanding, it is planned that INCEFAPLUS will develop and disseminate methods for including the new insights into assessment procedures for environmental fatigue degradation. This will take better account of the effects of mean strain, hold time and surface finish. This paper will provide more details on the background to this project and the way the project is organized to meet its objectives. Details will be provided as to how uncertainties due to variations in testing practice and specimen preparation have been minimized. Additionally, the choices associated with testing for the effects of surface finish, hold time and mean stress will be described along with the status of decisions so far within the project. The paper will also report current status of the project and when findings are likely to be disseminated

Assessment of notched structural steel components using failure assessment diagrams and the theory of critical distances

When the structural integrity of notched components is analysed, it is generally assumed that notches behave as cracks, something which generally provides overconservative results. The proposal of this paper consists, on the one hand, in the application of the theory of critical distances for the estimation of the notch fracture toughness and, therefore, for the conversion of the notched situation into an equivalent cracked situation in which the material develops a higher fracture resistance. On the other hand, once the notch fracture toughness has been defined, the assessment is performed using the failure assessment diagram methodology, and assuming that the notch effect on the limit load is negligible. The methodology has been applied to 336 CT notched fracture specimens made of two different structural steels, covering temperatures from the corresponding lower shelf up to the upper shelf, providing satisfactory results and a noticeable reduction in the overconservatism derived from the analyses in which the notch effect is not considered

On the Line Method apparent fracture toughness evaluations: experimental overview, validation and some consequences on fracture assessments

This paper analyses the capacity of the Line Method to provide evaluations of the apparent fracture toughness, which is the fracture resistance exhibited by materials in notched conditions. With this aim, the experimental results obtained in 555 fracture tests are homogeneously presented and compared to the Line Method evaluations. It is remarked that the Line Method provides adequate estimates of the apparent fracture toughness, and also that it conveniently addresses the physics of the notch effect. All this makes the Line Method a valuable scientific and engineering tool for the fracture assessment of materials containing notches

Protective role of nutraceuticals against myocarditis

Myocarditis is an inflammatory disease of the myocardium that mostly affects young adults. The disease is commonly caused by viral infection, medications, autoimmune disorders, and inflammatory conditions. Nearly 50% of the cases of myocarditis are due to post-viral immune response in a setting of an identifiable or non-identifiable infection. The clinical manifestation is nonspecific ranging from asymptomatic courses to sudden death in infants and young patients. This review describes the properties of phytochemicals as plant-derived active ingredients which can be used in the prevention and treatment of myocarditis and its associated risk factors. Meanwhile, it has illustrated epidemiological analyses, mechanism of action, and the metabolism of phytochemicals in animal and human clinical trials. We also mentioned the precise mechanism of action by which phytochemicals elicit their anti-viral, anti-inflammatory, antioxidant, and immunomodulatory effects and how they regulate signal transduction pathways. Nevertheless, comprehensive clinical trials are required to study the properties of phytochemicals in vivo, in vitro, and in silico for a proper management of myocarditis. Our findings indicate that phytochemicals function as potent adjunctive therapeutic drugs in myocarditis and its related complications

Application and validation of the notch master curve in medium and high strength structural steels

This paper applies and validates the Notch master curve in two ferritic steels with medium (steel S460M) and high (steel S690Q) strength. The Notch master curve is an engineering tool that allows the fracture resistance of notched ferritic steels operating within their corresponding ductile-to-brittle transition zone to be estimated. It combines the Master curve and the Theory of critical distances in order to take into account the temperature and the notch effect respectively, assuming that both effects are independent. The results, derived from 168 fracture tests on notched specimens, demonstrate the capability of the Notch master curve for the prediction of the fracture resistance of medium and high strength ferritic steels operating within their ductile-to-brittle transition zone and containing notches

fixation free inguinal hernia repair with the 3d dynamic responsive prosthesis proflor features procedural steps and long term results

Abstract Background Static and fixated meshes to repair mobile structures like the groin may seem a procedural incongruence. Inguinal hernia is described as a degenerative disease. Therefore, the objective of disease treatment should be the regeneration of wasted tissue. The fibrotic scar plate, a typical biologic response of conventional static meshes, does not represent tissue regeneration but rather a foreign body reaction. These contrasting aspects seem to be related to high complication rates of inguinal herniorrhaphy. Recent studies concerning the pathophysiology of the groin have led to the development of new concepts for repairing inguinal protrusions. A proprietary designed 3D dynamic responsive implant showing regenerative biologic response is the result of this studies. Materials and methods A cohort of 389 individuals underwent open inguinal hernia repair with the 3D dynamic responsive implant following a specific surgical technique. Thanks to the inherent dynamic properties, all procedures were performed without need for fixation of the 3D prosthesis. Results The outcomes of the dynamic hernia repair procedure were reduced postoperative pain and minimized overall complication rates, also long term. Moreover, no patient discomfort or chronic pain was reported. Conclusions Inguinal hernia repair with the 3D dynamic responsive implant ProFlor seems to represent an effective concept change for the treatment of this widespread degenerative disease. Moving in synchrony with the groin, implanted without need of fixation and acting as a regenerative scaffold, ProFlor™ appears to possess all that is needed for a physiologic and pathogenetical consequent treatment of inguinal protrusions leading to a dramatic lessening of intra- and postoperative complications

Chemical characterization and surface properties of a new bioemulsifier produced by Pedobacter sp. strain MCC-Z

A novel biopolymer was described in the form of an extracellular polysaccharide (EPS) by Pedobacter sp.strain MCC-Z, a member of a bacterial genus not previously described as an emulsifier producer. Thenew biomolecule was extracted, purified and characterized, and its surface and emulsifying propertieswere evaluated. The purified bioemulsifier, named Pdb-Z, showed high emulsifying activity (E24% = 64%)and reduced the surface tension of water up to 41 mN/m with a critical micelle concentration value of2.6 mg/mL. The chemical characterization of Pdb-Z was performed using1H NMR, FT-IR, HPLC/MS/MS andGC/MS. Pdb-Z was found to contain 67% of carbohydrates, consisting mainly of galactose and minor quan-tities of talose, 30% of lipids, being pentadecanoic acid the major lipidic constituent, and 3% of proteins. Thebioemulsifier was a glycolipids-protein complex with an estimated molecular mass of 106Da. Further-more, Pdb-Z emulsified pure aliphatic and aromatic hydrocarbons as well as diesel more efficiently thancommercial synthetic surfactants, used for comparison. Our results suggest Pdb-Z has interesting prop-erties for applications in remediation of hydrocarbon-contaminated environments and bioremediation processes

Fatigue Behavior of High Strength Steel S890Q Containing Thermally Cut Straight Edges

This paper evaluates the effect of different thermal cutting methods on the fatigue life of high strength steel S890Q. The investigation covers flame, plasma and laser cutting methodologies, and specimens with rectangular sections and cut straight edges. The experimental program is composed of 30 specimens that were conducted to failure by applying fatigue cycles with a stress ratio (R) of 0.1 in a high frequency testing machine. The resultant best-fit S-N curves have been compared, revealing a better performance for laser cut straight edges. Moreover, the corresponding Eurocode 3 FAT class has been derived for each of the three cutting methods, resulting in FAT160 in all cases. This suggests that the use Eurocode 3 FAT125, which is the fatigue class currently provided for flame cut straight edges, is an overconservative assumption for thermally cut straight edges in steel S890Q, regardless of the thermal cutting technique being used (flame, laser or plasma)