scholarly journals On the Zr Electrochemical Conversion of Additively Manufactured AlSi10Mg: The Role of the Microstructure

2021 ◽  
Author(s):  
Reynier Inocente Revilla ◽  
Clara Anna Rybin ◽  
Iris De Graeve
Keyword(s):  
Cast Alloy ◽  
Conversion Coating ◽  
Corrosion Performance ◽  
Electrochemical Conversion ◽  
Intermetallic Particles ◽  
Fine Microstructure ◽  
Protection Mechanisms ◽  
Mechanical Properties And Corrosion ◽  
First Time

Abstract Additively manufactured (AM) AlSi10Mg is one of the most studied AM aluminium alloys to date. While several studies have focused on investigating its mechanical properties and corrosion performance, very little work has been dedicated to study corrosion protection mechanisms and surface treatments applicable for this material. This work presents for the first time an analysis of the mechanism of Zr electrochemical conversion on AM AlSi10Mg parts. A comparison with the conventional cast alloy was also conducted. An analysis of the specimens using SEM/EDS provided interesting insights concerning the effect of the microstructure on the deposition of the Zr conversion layer. This work demonstrates that due to the very fine microstructure and distribution of alloying elements in AM AlSi10Mg, a homogeneous deposition of the Zr conversion layer is promoted. Conversely, the cast alloy is characterized by a very heterogeneous deposition of the Zr conversion layer due to the presence of relatively large Fe-containing intermetallic particles. The influence of the conversion coating on the corrosion performance of these materials was also studied. The results show that while the conversion treatment has no impact on the corrosion resistance of the cast alloy, it greatly improves the passivity of the AM AlSi10Mg samples.

scholarly journals Role of Chemical Composition in Corrosion of Aluminum Alloys

Metals ◽  
2018 ◽  
Vol 8 (8) ◽  
pp. 581 ◽  
Author(s):  
Lenka Kuchariková ◽  
Tatiana Liptáková ◽  
Eva Tillová ◽  
Daniel Kajánek ◽  
Eva Schmidová
Keyword(s):  
Chemical Composition ◽  
Aluminum Alloys ◽  
Cast Alloy ◽  
Critical Role ◽  
Secondary Aluminum ◽  
Corrosion Properties ◽  
Alloy Matrix ◽  
Exposure Test ◽  
Mechanical Properties And Corrosion

Aluminum alloys are the most important part of all shaped castings manufactured, especially in the aerospace and automotive industries. This work focuses on the corrosion properties of the heat-hardening aluminum alloys commonly used for production of automotive castings AlSi7Mg0.3 and on self-hardening AlZn10Si8Mg. Iron is a common impurity in aluminum cast alloy and its content increases by using secondary aluminum alloys. Therefore, experimental materials were developed, with chemical composition according to standards (primary alloys) and in states with an increasing content of Fe. The experimental aluminum alloys are briefly discussed in terms of their chemical composition, microstructure, mechanical properties and corrosion behavior. Corrosion properties were examined using three types of corrosion tests: exposure test, potentiodynamic tests, and Audi tests. Corrosion characteristics of materials were evaluated using stereo, optical and scanning electron microscopy, energy dispersive X-ray analysis, too. Correlation of pit initiation sites with microstructural features revealed the critical role of iron-rich phases, silicon particles and corresponding alloy matrix.

scholarly journals A Study of the Localized Ceria Coating Deposition on Fe-Rich Intermetallics in an AlSiFe Cast Alloy

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3058
Author(s):  
Salil Sainis ◽  
Caterina Zanella
Keyword(s):  
Aluminium Alloys ◽  
Cast Alloy ◽  
Conversion Coating ◽  
Precipitation Reaction ◽  
Coating Solution ◽  
Intermetallic Particles ◽  
Short Period ◽  
Coating Formation ◽  
Work Model ◽  
Galvanic Couples

Corrosion inhibiting conversion coating formation is triggered by the activity of micro-galvanic couples in the microstructure and subsequent local increase in pH at cathodic sites, which in the case of aluminium alloys are usually intermetallics. Ceria coatings are formed spontaneously upon immersion of aluminium alloys in a cerium conversion coating solution, the high pH gradient in the vicinity of intermetallics drives the local precipitation of ceria conversion compounds. Cu-rich intermetallics demonstrate a highly cathodic nature and have shown the local precipitation reaction to occur readily. Fe-rich intermetallics are, however, weaker cathodes and have shown varied extents of localized deposits and are in focus in the current work. Model cast Al-7wt.%Si alloys have been designed with 1 wt.% Fe, solidified at different cooling rates to achieve two different microstructures, with big and small intermetallics, respectively. Upon subjecting the two microstructures to the same conversion coating treatment (immersion in a 0.1 M CeCl3 solution) for a short period of 2 h, preferential heavy deposition on the boundaries of the big intermetallics and light deposition on the small intermetallics was observed. Based on these observations, a mechanism of localized coating initiation at these Fe-rich intermetallic particles (IM) is proposed.

Psychological Resilience Provides No Independent Protection From Suicidal Risk

Crisis ◽  
2016 ◽  
Vol 37 (2) ◽  
pp. 130-139 ◽  
Author(s):  
Danica W. Y. Liu ◽  
A. Kate Fairweather-Schmidt ◽  
Richard Burns ◽  
Rachel M. Roberts ◽  
Kaarin J. Anstey
Keyword(s):  
Risk Factors ◽  
Well Being ◽  
Current Status ◽  
Psychological Resilience ◽  
Cross Sectional ◽  
Life Project ◽  
Resilience Factors ◽  
First Time

Abstract. Background: Little is known about the role of resilience in the likelihood of suicidal ideation (SI) over time. Aims: We examined the association between resilience and SI in a young-adult cohort over 4 years. Our objectives were to determine whether resilience was associated with SI at follow-up or, conversely, whether SI was associated with lowered resilience at follow-up. Method: Participants were selected from the Personality and Total Health (PATH) Through Life Project from Canberra and Queanbeyan, Australia, aged 28–32 years at the first time point and 32–36 at the second. Multinomial, linear, and binary regression analyses explored the association between resilience and SI over two time points. Models were adjusted for suicidality risk factors. Results: While unadjusted analyses identified associations between resilience and SI, these effects were fully explained by the inclusion of other suicidality risk factors. Conclusion: Despite strong cross-sectional associations, resilience and SI appear to be unrelated in a longitudinal context, once risk/resilience factors are controlled for. As independent indicators of psychological well-being, suicidality and resilience are essential if current status is to be captured. However, the addition of other factors (e.g., support, mastery) makes this association tenuous. Consequently, resilience per se may not be protective of SI.

Synergetic Theory of Document in Evolution of Document Science

2018 ◽  
pp. 1060-1068
Author(s):  
Galina A. Dvoenosova ◽  
Keyword(s):  
Social Role ◽  
Scientific Study ◽  
Self Organization ◽  
Universal Theory ◽  
Social Self ◽  
Social Goal ◽  
The Social ◽  
Synergetic Theory ◽  
First Time

The article assesses synergetic theory of document as a new development in document science. In information society the social role of document grows, as information involves all members of society in the process of documentation. The transformation of document under the influence of modern information technologies increases its interest to representatives of different sciences. Interdisciplinary nature of document as an object of research leads to an ambiguous interpretation of its nature and social role. The article expresses and contends the author's views on this issue. In her opinion, social role of document is incidental to its being a main social tool regulating the life of civilized society. Thus, the study aims to create a scientific theory of document, explaining its nature and social role as a tool of social (goal-oriented) action and social self-organization. Substantiation of this idea is based on application of synergetics (i.e., universal theory of self-organization) to scientific study of document. In the synergetic paradigm, social and historical development is seen as the change of phases of chaos and order, and document is considered a main tool that regulates social relations. Unlike other theories of document, synergetic theory studies document not as a carrier and means of information transfer, but as a unique social phenomenon and universal social tool. For the first time, the study of document steps out of traditional frameworks of office, archive, and library. The document is placed on the scales with society as a global social system with its functional subsystems of politics, economy, culture, and personality. For the first time, the methods of social sciences and modern sociological theories are applied to scientific study of document. This methodology provided a basis for theoretical vindication of nature and social role of document as a tool of social (goal-oriented) action and social self-organization. The study frames a synergetic theory of document with methodological foundations and basic concepts, synergetic model of document, laws of development and effectiveness of document in the social continuum. At the present stage of development of science, it can be considered the highest form of theoretical knowledge of document and its scientific explanatory theory.

Physical Warmth Attenuates Ethnocentric Bias under Mortality Salience: An Embodied Terror Management Perspective

2020 ◽  
Author(s):  
Armand Chatard ◽  
Margaux Renoux ◽  
Jean Monéger ◽  
Leila Selimbegovic
Keyword(s):  
Mortality Salience ◽  
Terror Management ◽  
Negative Consequences ◽  
Defensive Reaction ◽  
Worldview Defense ◽  
Management Perspective ◽  
Physical Warmth ◽  
Alternative Means ◽  
First Time

Research indicates that individuals often deal with mortality salience by affirming beliefs in national or cultural superiority (worldview defense). Because worldview defense may be associated with negative consequences (discrimination), it is important to identify alternative means to deal with death-related thoughts. In line with an embodied terror management perspective, we evaluate for the first time the role of physical warmth in reducing defensive reaction to mortality salience. We predicted that, like social affiliation (social warmth), physical warmth could reduce worldview defense when mortality is salient. In this exploratory (preregistered) study, 202 French participants were primed with death-related thoughts, or an aversive control topic, in a heated room or a non-heated room. The main outcome was worldview defense (ethnocentric bias). We found no main effect of mortality salience on worldview defense. However, physical warmth reduced worldview defense when mortality was salient. Implications for an embodied terror management perspective are discussed.

Relationship between big five personality model and abusive supervision

2019 ◽  
Vol 12 (2) ◽  
Author(s):  
Bibi Tahira ◽  
Naveed Saif ◽  
Muhammad Haroon ◽  
Sadaqat Ali
Keyword(s):  
Big Five ◽  
Abusive Supervision ◽  
State Universities ◽  
Big Five Personality ◽  
Big Five Model ◽  
The Impact ◽  
First Time ◽  
Supervisor Behavior ◽  
Moderating Role

The current study tries to understand the diverse nature of relationship between personality Big Five Model (PBFM) and student's perception of abusive supervision in higher education institutions of Khyber Pakhtoonkhwa Pakistan. Data was collected in dyads i.e. (supervisors were asked to rate their personality attributes while student were asked to rate the supervisor behavior) through adopted construct. For this purpose, data was collected from three government state universities and one Private Sector University. The focus was on MS/M.Phill and PhD student and their supervisors of the mentioned universities. After measuring normality and validity regression analysis was conducted to assess the impact of supervisor personality characteristics that leads to abusive supervision. Findings indicate interestingly that except agreeableness other four attributes of (PBFM) are play their role for abusive supervision. The results are novel in the nature as for the first time Neuroticism, openness to experience, extraversion and conscientiousness are held responsible for the abusive supervision. The study did not explore the demographic characteristics, and moderating role of organizational culture, justice and interpersonal deviances to understand the strength of relationship in more detail way. Keywords: Personality big five model, abusive supervision, HEIs

Smolensk Proper Names in A.T. Tvardovsky’s Poems

2020 ◽  
pp. 54-62
Author(s):  
Inna A. Koroleva ◽  
Keyword(s):  
Proper Names ◽  
Personal Characteristics ◽  
Entire Body ◽  
Literary Works ◽  
Thematic Content ◽  
Home Town ◽  
Birthday Anniversary ◽  
Long Poems ◽  
First Time

This article is dedicated to the 110th birthday anniversary of a great Russian poet, native of Smolensk, one of the founders of the Smolensk Poetic School Aleksandr Tvardovsky (1910–1971). It examines how Smolensk motifs and Tvardovsky’s love for his home town are reflected in his works at the onomastic level. Smolensk-onyms reflected in long poems are analysed here, the focus being on anthroponyms and toponyms naming the characters and indicating the locations associated with Smolensk region. A close connection between the choice of proper names and Tvardovsky’s biography is established. An attempt is made to demonstrate how, using onomastic units introduced by the author into the storyline of his artistic text, the general principles of autobiography and chronotopy are realized, which have been noted earlier in critiques of Tvardovsky’s literary works. The onomastic component of the poems is analysed thoroughly and comprehensively, which helps us to decode the conceptual chain writer – name – text – reader and identify the author’s attitude to the characters and the ideological and thematic content of the works, as well as some of the author’s personal characteristics, tastes and passions. At the onomastic level, the thesis about the role of Smolensk motifs in Tvardovsky’s literary works is once more substantiated. A review is presented of onomastic studies analysing proper names of different categories in Tvardovsky’s poems (mainly conducted by the representatives of the Voronezh Onomastic School and the author of this article). It should be noted that Smolensk proper names in the entire body of Tvardovsky’s poetry are analysed for the first time.

Resveratrol: A new potential therapeutic agent for melanoma?

2019 ◽  
Vol 26 ◽  
Author(s):  
Mohamad Hossein Pourhanifeh ◽  
Kazem Abbaszadeh-Goudarzi ◽  
Mohammad Goodarzi ◽  
Sara G.M. Piccirillo ◽  
Alimohammad Shafiee ◽  
...  
Keyword(s):  
Quality Of Life ◽  
Therapeutic Agent ◽  
Current Knowledge ◽  
Treatment Resistance ◽  
Anti Cancer ◽  
Apoptosis Inducer ◽  
Life Threatening ◽  
First Time

: Melanoma is the most life-threatening and aggressive class of skin malignancies. The incidence of melanoma has steadily increased. Metastatic melanoma is greatly resistant to standard anti-melanomatreatments such as chemotherapy, and 5-year survival rate of cases with melanoma who have metastatic form of disease is less than 10%. The contributing role of apoptosis, angiogenesis and autophagy in the pathophysiology of melanoma has been previously demonstrated. Thus, it is extremely urgent to search for complementary therapeutic approachesthat couldenhance the quality of life of subjects and reduce treatment resistance and adverse effects. Resveratrol, known as a polyphenol component present in grapes and some plants, has anti-cancer properties due to its function as an apoptosis inducer in tumor cells, and anti-angiogenic agent to prevent metastasis. However, more clinical trials should be conducted to prove resveratrol efficacy. : Herein, for first time, we summarize current knowledge of anti-cancerous activities of resveratrol in melanoma.

Laws of Nature

2018 ◽  
Keyword(s):  
Philosophy Of Science ◽  
Laws Of Nature ◽  
Current Debate ◽  
Scientific Theories ◽  
Law Of Nature ◽  
First Time ◽  
The Universe

The concept of a law of nature, while familiar, is deeply puzzling. Theorists such as Descartes think a divine being governs the universe according to the laws which follow from that being’s own nature. Newton detaches the concept from theology and is agnostic about the ontology underlying the laws of nature. Some later philosophers treat laws as summaries of events or tools for understanding and explanation, or identify the laws with principles and equations fundamental to scientific theories. In the first part of this volume, essays from leading historians of philosophy identify central questions: are laws independent of the things they govern, or do they emanate from the powers of bodies? Are the laws responsible for the patterns we see in nature, or should they be collapsed into those patterns? In the second part, contributors at the forefront of current debate evaluate the role of laws in contemporary Best System, perspectival, Kantian, and powers- or mechanisms-based approaches. These essays take up pressing questions about whether the laws of nature can be consistent with contingency, whether laws are based on the invariants of scientific theories, and how to deal with exceptions to laws. These twelve essays, published here for the first time, will be required reading for anyone interested in metaphysics, philosophy of science, and the histories of these disciplines.

Sign in / Sign up

Export Citation Format

Share Document