Orientation Relationship during Partial α-γ-Phase Transformation in Microalloyed Steels

2005 ◽  
Vol 495-497 ◽  
pp. 447-452 ◽  
Author(s):  
I. Lischewski ◽  
Günter Gottstein
Keyword(s):  
Phase Transformation ◽  
Orientation Relationship ◽  
Microalloyed Steel ◽  
Austenite Phase ◽  
Microalloyed Steels ◽  
Special Focus ◽  
Partial Phase ◽  
Growth Selection

The ferrite to austenite phase transformation in microalloyed steel was studied, with a special focus on the orientation relationship between prior ferrite and subsequent austenite. Also the role of growth selection and preferred nucleation was investigated in this context. Their effects were examined at partial phase transformation.

scholarly journals Effects of deformation on the microstructure of a Ti-V microalloyed steel in the phase transition region

2004 ◽  
Vol 57 (4) ◽  
pp. 303-311
Author(s):  
Wiliam Regone ◽  
Sérgio Tonini Button
Keyword(s):  
Phase Transition ◽  
Phase Transformation ◽  
Transition Region ◽  
Microstructural Evolution ◽  
Microalloyed Steel ◽  
Hot Forging ◽  
Microalloyed Steels ◽  
Air Cooling ◽  
Water Cooling ◽  
Phase Transition Region

Microalloyed steels are used in the forging of many automotive parts like crankshafts and connecting rods. They are hot worked in a sequence of stages that includes the heating to the soaking temperature, followed by forging steps, and finally the controlled cooling to define the microstructure and mechanical properties. In this work it was investigated the thermomechanical behavior and the microstructural evolution of a Ti-V microalloyed steel in the phase transition region. Torsion tests were done with multiple steps with true strain equal to 0.26 in each step. After each torsion step the samples were continuous cooled for 15 seconds to simulate hot forging conditions. These tests provided results for the temperature at the beginning of the phase transformation, and allowed to analyze the microstructural changes. Also, workability tests were held to analyze the microstructural evolution by optical and scanning electron microscopy. Results from the torsion tests showed that the temperature for the beginning of phase transformation is about 700 ºC. Workability tests held at 700 ºC followed by water-cooling presented microstructures with different regions: strain hardened, and static and dynamic recrystallized. Workability tests at 700 ºC followed by air-cooling showed a complex microstructure with ferrite, bainite and martensite, while tests at 650 and 600 ºC followed by water-cooling showed a microstructure with allotriomorphic ferrite present in the grain boundaries of the previous austenite.

scholarly journals On the Determining Role of Texture in Causing Delamination During Impact Fracture of Ti and Nb-Ti Microalloyed Steel

2019 ◽  
Author(s):  
Mingyu Sun ◽  
Xuemin Wang ◽  
R.D.K. Misra
Keyword(s):  
Impact Toughness ◽  
Fracture Surface ◽  
Impact Energy ◽  
Cleavage Fracture ◽  
Microalloyed Steel ◽  
Microalloyed Steels ◽  
Brittle Transition ◽  
High Toughness ◽  
The Impact

700 MPa grade Ti and Nb-Ti microalloyed steels produced by thermo-mechanical control rolled processes (TMCP) were studied to elucidate texture that contributes to delamination and consequent impact toughness. The microstructure of Ti and Nb-Ti steels consisted of ferrite and bainite. Compared with Ti steel, Nb-Ti steel was characterized by a microstructure with finer ferrite and more bainite. The results from tensile and impact tests indicated that there is insignificant change in tensile properties, but toughness was greater in Nb-Ti steel compared with Ti steel. More severe delamination in Nb-Ti steel is attributed to stronger α-fiber (RD ||<110>) texture than Ti steel, especially {100}<110>, {113}<110> and {112}<110> texture. Typical cleavage river patterns were not observed on delaminated fracture surface, instead the cleavage fracture surface indicated some dimples. Interestingly, the impact energy of samples with delamination was greater than samples without delamination in the ductile–brittle transition region. The study suggests that delamination in the ductile–brittle transition zone may also be representative of high toughness.

FAITH–BASED COMMUNITIES AND POLITICS IN DULLSTROOM-EMNOTWENI: LOCAL STORIES OF IDENTITY

2016 ◽  
Vol 1 (1) ◽  
pp. 45-57 ◽  
Author(s):  
Christina Landman
Keyword(s):  
Higher Education ◽  
Service Delivery ◽  
Special Focus ◽  
Traditional Role ◽  
Cultural Conflicts ◽  
Local Identities ◽  
Political Interests ◽  
Local Municipality ◽  
The Face

A majority of the black community of Dullstroom-Emnotweni in the Mpumalanga highveld in the east of South Africa trace their descent back to the southern Ndebele of the so-called ‘Mapoch Gronden’, who lost their land in the 1880s to become farm workers on their own land. A hundred years later, in 1980, descendants of the ‘Mapoggers’ settled in the newly built ‘township’ of Dullstroom, called Sakhelwe, finding jobs on the railways or as domestic workers. Oral interviews with the inhabitants of Sakhelwe – a name eventually abandoned in favour of Dullstroom- Emnotweni – testify to histories of transition from landowner to farmworker to unskilled labourer. The stories also highlight cultural conflicts between people of Ndebele, Pedi and Swazi descent and the influence of decades of subordination on local identities. Research projects conducted in this and the wider area of the eMakhazeni Local Municipality reveal the struggle to maintain religious, gender and youth identities in the face of competing political interests. Service delivery, higher education, space for women and the role of faith-based organisations in particular seem to be sites of contestation. Churches and their role in development and transformation, where they compete with political parties and state institutions, are the special focus of this study. They attempt to remain free from party politics, but are nevertheless co-opted into contra-culturing the lack of service delivery, poor standards of higher education and inadequate space for women, which are outside their traditional role of sustaining an oppressed community.

Can the Lewis basicity of an isolated solvent molecule be used for characterizing solvent effects?

2020 ◽  
Vol 16 ◽  
Author(s):  
Jean-François Gal ◽  
Pierre-Charles Maria
Keyword(s):  
Solvent Effects ◽  
Molecular Level ◽  
Solvent Molecule ◽  
Lewis Base ◽  
Bulk Liquid ◽  
Donor Number ◽  
Special Focus ◽  
Solution Processes ◽  
Inert Solvent

Background: The ubiquitous Lewis acid/base interactions are important in solution processes. Analytical chemistry may benefit of a better understanding of the role of Lewis basicity, at the molecular level or acting through a bulk solvent effect. Objective: To clearly delineate (i) the basicity at a molecular level, hereafter referred as solute basicity, and (ii) the solvent basicity, which is a bulk-liquid property. Method: The literature that relates Lewis basicity scales and solvent effects is analyzed. A special focus is placed on two extensive scales, the Donor Number, DN, and the BF3 affinity scale, BF3A, which were obtained by calorimetric measurement on molecules as solutes diluted in a quasi-inert solvent, and therefore define a molecular Lewis basicity. We discuss the validity of these solute scales when regarded as solvent scales, in particular when the basicity of strongly associated liquids is discussed. Results: We demonstrate the drawbacks of confusing the Lewis basicity of a solvent molecule, isolated as solute, and that of the bulk liquid solvent itself. Conclusion: Consequently, we recommend a reasoned use of the concept of Lewis basicity taking clearly into account the specificity of the process for which a Lewis basicity effect may be invoked. In particular, the action of the Lewis base, either as an isolated entity, or as a bulk liquid, must be distinguished.

scholarly journals Hypoxia, Acidification and Inflammation: Partners in Crime in Parkinson’s Disease Pathogenesis?

Immuno ◽  
2021 ◽  
Vol 1 (2) ◽  
pp. 78-90
Author(s):  
Johannes Burtscher ◽  
Grégoire P. Millet
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Neurodegenerative Diseases ◽  
Current Knowledge ◽  
Cell Types ◽  
Brain Cell ◽  
Special Focus ◽  
Molecular Alterations ◽  
Research Fields

Like in other neurodegenerative diseases, protein aggregation, mitochondrial dysfunction, oxidative stress and neuroinflammation are hallmarks of Parkinson’s disease (PD). Differentiating characteristics of PD include the central role of α-synuclein in the aggregation pathology, a distinct vulnerability of the striato-nigral system with the related motor symptoms, as well as specific mitochondrial deficits. Which molecular alterations cause neurodegeneration and drive PD pathogenesis is poorly understood. Here, we summarize evidence of the involvement of three interdependent factors in PD and suggest that their interplay is likely a trigger and/or aggravator of PD-related neurodegeneration: hypoxia, acidification and inflammation. We aim to integrate the existing knowledge on the well-established role of inflammation and immunity, the emerging interest in the contribution of hypoxic insults and the rather neglected effects of brain acidification in PD pathogenesis. Their tight association as an important aspect of the disease merits detailed investigation. Consequences of related injuries are discussed in the context of aging and the interaction of different brain cell types, in particular with regard to potential consequences on the vulnerability of dopaminergic neurons in the substantia nigra. A special focus is put on the identification of current knowledge gaps and we emphasize the importance of related insights from other research fields, such as cancer research and immunometabolism, for neurodegeneration research. The highlighted interplay of hypoxia, acidification and inflammation is likely also of relevance for other neurodegenerative diseases, despite disease-specific biochemical and metabolic alterations.

scholarly journals 26.A. Workshop: Assessing the role of policies and actions to address childhood obesity

2020 ◽  
Vol 30 (Supplement_5) ◽  
Author(s):  
◽  
Keyword(s):  
Public Health ◽  
Childhood Obesity ◽  
Stakeholder Engagement ◽  
Special Focus ◽  
Policy Options ◽  
Sustainable Solutions ◽  
Relevant Evidence ◽  
Multi Stakeholder ◽  
The Impact

Abstract   Childhood obesity has grown to become one of the most dramatic features of the global obesity epidemic, with long-term consequences. The spread of obesity has been fueled by changes in social norms and living environments that have shaped individual behaviours making them conducive to excessive and imbalanced nutrition, sedentary lifestyles, and ultimately obesity and associated diseases. The STOP project will aim to generate scientifically sound, novel and policy-relevant evidence on the factors that have contributed to the spread of childhood obesity in European countries and on the effects of alternative technological and organisational solutions and policy options available to address the problem. STOP will translate the evidence gathered and generated into indicators and measurements, policy briefs and toolkits and multi-stakeholder frameworks. A special focus of STOP is understanding the stakeholders' networks and drivers of stakeholders' action. STOP will establish new ways for policy-relevant evidence to be generated, made available and used in the design and implementation of effective and sustainable solutions for childhood obesity at the EU, national and local levels. Each of the policy work packages will: Produce evidence syntheses and impact simulations for different policy approaches;Assess selected policy approaches and actions in children cohorts and other relevant settings;Devise policy toolkits and policy guidance to support the adoption and implementation of specific actions by relevant actors;Establish a country-based European accountability and monitoring framework in each policy area. The workshop aims to: Showcase the impact of different policy options evaluated throughout the STOP project;Increase participants' understanding and awareness of the opportunities and challenges associated with the implementation of selected policies;Increase awareness of public health professionals of the importance of overcoming siloes in identifying and implementing public health policies;Increase the understanding of multi-stakeholder engagement. The discussion will explore the role of stakeholders across different policy areas. We will explore the different definitions of “stakeholders” and “multi-stakeholders” engagement. This will also be an opportunity to explore some of the benefits, risks and challenges around stakeholder engagement, and explore what are the different types of stakeholders involved in these policies as well as their roles. The workshop will offer an opportunity to: Inform participants about existing physical activity, regulatory and fiscal policies to address childhood obesity;Inform participants about new, innovative EU-level projects that aim to address childhood obesity;Outline preliminary findings of the STOP project with regards to the effectiveness of the evaluated policies;Identify some of the gaps and limitations of existing policies and discuss some of the steps to ensure successful policy implementation. Key messages Present new evidence on what policy approaches work in addressing key determinants of childhood obesity. Showcase findings on the attitudes of different stakeholders towards obesity policies, and debate the benefits, risks and challenges of multi-stakeholder engagement.

scholarly journals Erythrocytes: Central Actors in Multiple Scenes of Atherosclerosis

2021 ◽  
Vol 22 (11) ◽  
pp. 5843
Author(s):  
Chloé Turpin ◽  
Aurélie Catan ◽  
Olivier Meilhac ◽  
Emmanuel Bourdon ◽  
François Canonne-Hergaux ◽  
...  
Keyword(s):  
Iron Homeostasis ◽  
The Body ◽  
Diabetic Patients ◽  
Special Focus ◽  
Plaque Progression ◽  
Cell Dysfunction ◽  
Circulating Cells ◽  
The Impact ◽  
Progression Of Atherosclerosis

The development and progression of atherosclerosis (ATH) involves lipid accumulation, oxidative stress and both vascular and blood cell dysfunction. Erythrocytes, the main circulating cells in the body, exert determinant roles in the gas transport between tissues. Erythrocytes have long been considered as simple bystanders in cardiovascular diseases, including ATH. This review highlights recent knowledge concerning the role of erythrocytes being more than just passive gas carriers, as potent contributors to atherosclerotic plaque progression. Erythrocyte physiology and ATH pathology is first described. Then, a specific chapter delineates the numerous links between erythrocytes and atherogenesis. In particular, we discuss the impact of extravasated erythrocytes in plaque iron homeostasis with potential pathological consequences. Hyperglycaemia is recognised as a significant aggravating contributor to the development of ATH. Then, a special focus is made on glycoxidative modifications of erythrocytes and their role in ATH. This chapter includes recent data proposing glycoxidised erythrocytes as putative contributors to enhanced atherothrombosis in diabetic patients.

Sign in / Sign up

Export Citation Format

Share Document