scholarly journals Minimal Invasive Diagnostic Capabilities and Effectiveness of CFRP-Patches Repairs in Long-Term Operated Metals

Metals ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 984
Author(s):  
Grzegorz Lesiuk ◽  
Bruno A. S. Pedrosa ◽  
Anna Zięty ◽  
Wojciech Błażejewski ◽  
Jose A. F. O. Correia ◽  
...  

The paper deals with the subject of diagnostics and the quick repairs of long-term operated metallic materials. Special attention was paid to historical materials, where the structure (e.g., puddle iron) is different from modern structural steels. In such materials, the processes of microstructural degradation occur as a result of several decades of exposure, which could overpass 100 years. In some cases, their intensity can be potentially catastrophic. For this reason, the search for minimally invasive diagnostic methods is ongoing. In this paper, corrosion and fracture toughness tests were conducted, and the results of these studies were presented for two material states: post-operated and normalized (as a state “restoring” virgin state). Moreover, through the use of modern numerical methods, composite crack-resistant patches have been designed to reduce the stress intensity factors under cyclic loads. As a result, fatigue lifetime was extended (propagation phase) by more than 300%.

2018 ◽  
Vol 84 (11) ◽  
pp. 46-51 ◽  
Author(s):  
N. A. Makhutov

The results of comprehensive studies of multifactor processes, mechanisms and criteria for fracture at a variation of the crack-like defect state, loading conditions and mechanical properties of structural materials carried out in the 20th - 21st centuries are presented on the basis of monographic publications and articles published in the journal “Zavodskaya Laboratoriya. Diagnostika Materialov.” Crack resistance of materials and structures has become a key problem of the material science, technology, design, manufacture and service of structures. Fracture mechanics including estimation of the stress-strain and limiting states in a cracks tip formed a scientific basis of the crack resistance analysis Stress intensity factors (linear fracture mechanics) and strain intensity factors (nonlinear fracture mechanics) are accepted as the basic criteria of those states. The basic computational relations for construction of the fracture diagrammes which link the cracks growth with conditions of a static, cyclic, long-term, dynamic loading are presented. Parameters of computational relations are put into correspondence with the features of fracture processes on nano-, micro-, meso- and macrolevels. Prospects of the research and guidelines of further studing crack resistance are discussed.


Nanoscale ◽  
2021 ◽  
Author(s):  
Srijan Acharya ◽  
Satyam Suwas ◽  
Kaushik Chatterjee

Metallic materials are widely used to prepare implants for both short-term and long-term use in the human body. The performance of these implants is greatly influenced by their surface characteristics,...


2019 ◽  
Vol 11 (4) ◽  
pp. 287-291
Author(s):  
Annette L. Gardner ◽  
Peter Bishop

The subject of evaluating foresight work has been around for almost as long as the professional practice itself has, but the field has done little to move closer to a systematic evaluation of its work. This special issue marks the second collection of articles on that project after a special issue of Futures in 2012 (Van Der Duin and Van Der Martin 2012). This issue takes a three-part approach: Part 1: evaluation of foresight in general and evaluation approaches and methods that can support designing an appropriate evaluation; Part 2: evaluation of foresight work in organizations and its impact on long-term thinking and decision-making; and Part 3: evaluation of specific foresight activities—an undergraduate learner foresight experience and a health sector scenario development exercise. The foreword ends with a reflection on the continuing issue of foresight and evaluation.


2011 ◽  
Vol 279 (1733) ◽  
pp. 1560-1566 ◽  
Author(s):  
Lee Koren ◽  
Shinichi Nakagawa ◽  
Terry Burke ◽  
Kiran K. Soma ◽  
Katherine E. Wynne-Edwards ◽  
...  

Potential mechanistic mediators of Darwinian fitness, such as stress hormones or sex hormones, have been the focus of many studies. An inverse relationship between fitness and stress or sex hormone concentrations has been widely assumed, although empirical evidence is scarce. Feathers gradually accumulate hormones during their growth and provide a novel way to measure hormone concentrations integrated over time. Using liquid chromatography–tandem mass spectrometry, we measured testosterone, corticosterone and cortisol in the feathers of house sparrows ( Passer domesticus ) in a wild population which is the subject of a long-term study. Although corticosterone is considered the dominant avian glucocorticoid, we unambiguously identified cortisol in feathers. In addition, we found that feathers grown during the post-nuptial moult in autumn contained testosterone, corticosterone and cortisol levels that were significantly higher in birds that subsequently died over the following winter than in birds that survived. Thus, feather steroids are candidate prospective biomarkers to predict the future survival of individuals in the wild.


2012 ◽  
Vol 13 (4) ◽  
pp. 312-332
Author(s):  
Malcolm Abbott

Throughout much of the history of the electricity industry in Australia and New Zealand the industry has been the subject of safety regulations. Although this regulation has been a constant throughout the life of the industry the organizational approach to regulation has changed over the years. Periodically in Australia and New Zealand history these questions have been raised in a political context, although notably the structure of safety regulators does not get much attention in the standard histories of the industry. The purpose of this paper, therefore, is to discuss some of the general issues that have arisen in the reform of regulation in the case of electricity safety over the longer term and how it relates overall to the development of the electricity industry.


2011 ◽  
Vol 3 (1-2) ◽  
pp. 68-83 ◽  
Author(s):  
Laryssa Chomiak

In their search for explanations for the so-called Tunisian paradox under Ben Ali –a country with comparatively high levels of socio-economic development, yet plagued by the absence of a civil society that could push for political liberalization–analysts primarily investigated the gradual co-optation of political institutions and actors. As research and analytical agendas were consumed by the robustness of Ben Ali’s authoritarian state, little attention was paid to the development of informal and extra-institutional political activities that existed even under deepening political repression. In hindsight, many of these informal activities clearly contributed to the December 2010-January 2011 nation-wide campaign, which eventually led to the Arab World’s fi rst bottom-up revolution ousting an unpopular and illegitimate ruler. Th is article will engage two stories about the Tunisian Revolution that later inspired protests and contentious activities across the Middle East and North Africa. First, it will tell a back-story of contentious activities preceding the January 2011 events that surprised observers, scholars and analysts–even those familiar with the Tunisian case. Second, this article will discuss some of most pressing political dynamics that have emerged in the post-revolutionary (and pre-October 2011 election) environment. The concluding section will subsequently identify avenues for short and long-term research on the subject of contestation, resistance, and the construction of a new political order.


2021 ◽  
Vol 62 (1) ◽  
pp. 43-80
Author(s):  
Wolfgang S. Heinz

Abstract: This article approaches the matter of institutional reform of the United Nations Human Rights Council from an international relations perspective. A well-known tension exists between State representatives acting for their governments in international organisations, but whose decisions are presented as UN policies. The latter should be guided primarily by the UN Charter and public international law. However, in reality, different worldviews and foreign policy considerations play a more significant role. In a comprehensive stock-take, the article looks at four major dimensions of the Council, starting with structure and dynamics and major trends, followed by its country and thematic activities, and the role of key actors. Council reform proposals from both States and civil society are explored. Whilst the intergovernmental body remains the most important authority responsible for the protection of human rights in the international sphere, it has also been the subject of considerable criticism. Although it has made considerable progress towards enlarging its coverage and taking on more challenging human rights crises, among some of its major weaknesses are the election of human rights-unfriendly countries into its ranks, the failure to apply stronger sanctions on large, politically influential countries in the South and North, and lack of influence on human rights crises and chronic human rights problems in certain countries. Whilst various reform proposals have emerged from States and NGOs, other more far reaching propositions are under sometimes difficult negotiations. In the mid- to long-term, the UN human rights machinery can only have a stronger and more lasting impact if support from national/local actors and coalitions in politics and society can be strengthened.


Author(s):  
Parisa Dehghani ◽  
Monireh Esameili Rad ◽  
Atefeh Zarepour ◽  
Ponnurengam Malliappan Sivakumar ◽  
Ali Zarrabi

: Diabetes mellitus (DM) is a type of chronic metabolic disease that has affected millions of people worldwide and is known with a defect in the amount of insulin secretion, insulin functions, or both. This deficiency leads to an increase in the amounts of glucose, which could be accompanied by long-term damages to other organs such as eyes, kidneys, heart, and nervous system. Thus, introducing an appropriate approach for diagnosis and treatment of different types of DM is the aim of several researches. By the emergence of nanotechnology and its application in medicine, new approaches were presented for these purposes. The object of this review article is to introduce different types of polymeric nanoparticles (PNPs), as one of the most important classes of nanoparticles, for diabetic management. To achieve this goal, at first, some of the conventional therapeutic and diagnostic methods of DM will be reviewed. Then, different types of PNPs, in two forms of natural and synthetic polymers with different properties, as a new method for DM treatment and diagnosis will be introduced. In the next section, the transport mechanisms of these types of nano-carriers across the epithelium, via paracellular and transcellular pathways will be explained. Finally, the clinical use of PNPs in the treatment and diagnosis of DM will be summarized. Based on the results of this literature review, PNPs could be considered one of the most promising methods for DM management.


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