Stray Current Induced Corrosion Control in Reinforced Concrete by Addition of Carbon Fiber and Silica Fume

2015 ◽  
Vol 1768 ◽  
Author(s):  
Zhipei Chen ◽  
Dessi Koleva ◽  
Eduard Koenders ◽  
Klaas van Breugel

ABSTRACTStray current arising from direct current electrified traction systems and then circulating in reinforced concrete near railways is known to induce corrosion on embedded steel reinforcement. The present paper will review the principles of stray current induced corrosion in reinforced concrete, which is relatively uncommon but with significant impact in practice.Within one of the approaches to ease this kind of specific corrosion in reinforced concrete, carbon fibres (CF) can be added to enhance the conductivity of concrete, subsequently reduce the stray current density and/or direct the stray current dissipation in a desired manner. The side effects (such as increasing the bulk matrix porosity) caused by CF, which can in turn reduce the general corrosion resistance of reinforced concrete, will be compensated by adding silica fume (SF). The combination of CF and SF can be a potentially feasible and original application to reduce the risk of stray current induced corrosion in reinforced concrete, without obvious negative side effects.

2018 ◽  
Vol 47 (4) ◽  
pp. 350-359 ◽  
Author(s):  
Nivin M. Ahmed ◽  
Mostafa G. Mohamed ◽  
Reham H. Tammam ◽  
Mohamed R. Mabrouk

Purpose This study aims to apply novel anticorrosive pigments containing silica fume-phosphates (Si-Ph), which were prepared using core-shell technique by covering 80-90 per cent silica fume (core) with 10-20 per cent phosphates (shell) previously, to play dual functions simultaneously as anticorrosive pigments in coating formulations and as an anticorrosive admixture in concrete even if it is not present in the concrete itself. Two comparisons were held out to show the results of coatings on rebars containing core-shell pigments in concrete, and concrete admixtured with silica fume can perform a dual function as anticorrosive pigment and concrete admixture. The evaluation of corrosion protection efficiency of coatings containing core-shell pigments and those containing phosphates was performed. Design/methodology/approach Simple chemical techniques were used to prepare core-shell pigments, and their characterization was carried out in a previous work. These pigments were incorporated in solvent-based paint formulations based on epoxy resin. Different electrochemical techniques such as open-circuit potential and electrochemical impedance spectroscopy were used to evaluate the anticorrosive efficiency of the new pigments. Findings The electrochemical measurements showed that concrete containing coated rebars with core-shell pigments exhibited almost similar results to that of concrete admixtured with silica fume. Also, the anticorrosive performance of coatings containing Si-Ph pigments offered protection efficiency almost similar to that of phosphates, proving that these new pigments can perform both roles as anticorrosive pigment and concrete admixture. Originality/value Although the new Si-Ph pigments contain more than 80 per cent waste material, its performance can be compared to original phosphate pigments in the reinforced concrete.


2021 ◽  
Vol 22 (4) ◽  
pp. 1710
Author(s):  
Sylwia Cyboran-Mikołajczyk ◽  
Przemysław Sareło ◽  
Robert Pasławski ◽  
Urszula Pasławska ◽  
Magdalena Przybyło ◽  
...  

Liposomal technologies are used in order to improve the effectiveness of current therapies or to reduce their negative side effects. However, the liposome–erythrocyte interaction during the intravenous administration of liposomal drug formulations may result in changes within the red blood cells (RBCs). In this study, it was shown that phosphatidylcholine-composed liposomal formulations of Photolon, used as a drug model, significantly influences the transmembrane potential, stiffness, as well as the shape of RBCs. These changes caused decreasing the number of stomatocytes and irregular shapes proportion within the cells exposed to liposomes. Thus, the reduction of anisocytosis was observed. Therefore, some nanodrugs in phosphatidylcholine liposomal formulation may have a beneficial effect on the survival time of erythrocytes.


2021 ◽  
Vol 10 (7) ◽  
pp. 1388
Author(s):  
Marta Malesza ◽  
Erich Wittmann

The main aim of this study was to investigate the various factors influencing COVID-19 vaccination acceptance and actual intake among older Germans aged over 75 years old (n = 1037). We found that the intention to get vaccinated or intake of the COVID-19 vaccine were positively related to the perceptions of becoming infected, perceptions of the severity of the potential long-term effects, the vaccine’s efficacy, and the benefits of vaccination. Meanwhile, the intention to get the vaccine or vaccine intake were decreased by perceptions of the negative side-effects and the general impediments to vaccination.


2021 ◽  
pp. 2046147X2110140
Author(s):  
Roumen Dimitrov

In this paper I analyse a series of Australian MMR (measles-mumpsrubella) vaccination campaigns and policies from the last decade. Using the Bruno Latour’s Actor Network Theory (ATN), I locate human and non-human mediators – including the virus and vaccine – in the complex pro-vaccination alliance led by government campaigners. I identify the vaccine hesitant parents – a large group that ‘sits on the fence’ between the ‘vaccine confident’ and ‘vaccine refusing’ parents – as the main target of pro-vaccination campaigns. PR literature on pro-vaccination campaigns has applied ATN to the independence of the media as network agents. This paper contributes with the problematisation of several more actors such as the health workers, medical experts and the vaccine hesitant parents themselves. Even when they are keen members of a pro-vaccination network, they cannot be taken for granted. This is where understanding of stigma, silence and voice helps. To align their group interests and discourses, government should know how to communicate strategically – including how to communicate indirectly, avoiding stigma and keeping certain internal affinities and communicative distances intact. In conclusion, I make suggestions about strategic communication in pro-vaccination campaigns. Communication of statistical risks and side effects should be central. It is a winning strategy because it establishes a more credible balance between individual rights and collective obligations in achieving herd immunity. And mandating vaccination cannot replace communication. Research shows that legislating compulsory vaccination may have short-term and relatively small effects. They are almost negligible in the long run. Mandate may trigger compliance, but it also causes anger and mistrust. Mandating vaccine has negative side effects. It punishes with economic and cultural sanctions the socially disadvantaged, who are not active refusers. It also has the opposite effect on vaccine hesitant parents. It does not weaken but rather strengthens their resistance to the vaccine and pushes them to the lager of antivaxxers.


2022 ◽  
Author(s):  
health not provided

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2021 ◽  
Author(s):  
hengstla not provided

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Author(s):  
Jasmina Cilerdzic ◽  
Mirjana Stajic ◽  
Jelena Vukojevic

Even though numerous lichen species possess significant medical potentials they are still unexplored, and particularly species and strains originating from Serbia. Therefore, the aim of this study was to evaluate the antioxidative and antimicrobial potential of ethanol extracts of Parmelia saxatilis and Pseudoevernia furfuracea collected in Serbia. The tested extracts were good scavengers of DPPH radicals, with capacities ranging from 14.76% to 79.76% in P. saxatilis and from 21.39% to 90.04% in P. furfuracea. In P. saxatilis level of DPPH? neutralisation was highly correlated with phenol content (r2 = 0.9981) and in P. furfuracea with amount of total flavonoides (r2 = 0.9641). The extract of P. furfuracea inhibited the growth of all tested microorganisms with exception of Aspergillus flavus, while P. saxatilis extract affected only growth of bacterial species. Among tested microorganisms, Staphylococcus aureus and Klebsiella pneumoniae were the most sensitive, while Enterococcus faecalis, Pseudomonas aeruginosa as well as micromycetes were the least sensitive to tested extracts. Because of these potentials and the fact that their long term usage does not have any negative side effects on organism and development of microbial resistance, the extracts could be included in conventional therapy.


2021 ◽  
Vol 22 (17) ◽  
pp. 9396
Author(s):  
Chloë Maes ◽  
Jeroen Meersmans ◽  
Laurence Lins ◽  
Sandrine Bouquillon ◽  
Marie-Laure Fauconnier

In recent years, the development of new bio-based products for biocontrol has been gaining importance as it contributes to reducing the use of synthetic herbicides in agriculture. Conventional herbicides (i.e., the ones with synthetic molecules) can lead to adverse effects such as human diseases (cancers, neurodegenerative diseases, reproductive perturbations, etc.) but also to disturbing the environment because of their drift in the air, transport throughout aquatic systems and persistence across different environments. The use of natural molecules seems to be a very good alternative for maintaining productive agriculture but without the negative side effects of synthetic herbicides. In this context, essential oils and their components are increasingly studied in order to produce several categories of biopesticides thanks to their well-known biocidal activities. However, these molecules can also be potentially hazardous to humans and the environment. This article reviews the state of the literature and regulations with regard to the potential risks related to the use of essential oils as bioherbicides in agricultural and horticultural applications.


Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Ping Xu ◽  
Rui Shi ◽  
Chao Wang ◽  
Yuhao Cui ◽  
Minxia Zhang

In order to develop textile reinforced concrete (TRC) with good flowability and strength, colloidal nano-SiO2 (CNS) is adopted to improve the performance of TRC. The flowability, compressive strength, flexural strength, and four-point bending tests of TRC matrix with CNS are carried out, and the changes of internal micromorphological characteristics of TRC matrix are analyzed by combining with scanning electron microscopy. The results show that the CNS has an inhibitory effect on the flowability of TRC matrix, and the greater the amount of admixture is, the smaller the slump expansion of TRC matrix is. The compressive strength and flexural strength of TRC matrix show a trend of increasing and then decreasing as the amount of CNS increases, and the compressive strength reaches the maximum at each age (7 d, 14 d, 28 d) when CNS and silica fume replace 5% cement by 1 : 4 equal mass. The flexural strength reaches the maximum at each age (7 d, 14 d, 28 d) when 5% cement is replaced by CNS and silica fume with 3 : 7 equal mass. The flexural strength increases with the increase of CNS admixture. It is found by electron microscope scanning that the incorporation of CNS consumes more Ca(OH)2, refines the Ca(OH)2 crystal size, and generates more C-S-H gels. These C-S-H gels are distributed in a net-like pattern inside the concrete, filling the internal pores, effectively densifying the interfacial transition zone between the cementitious material and the aggregates, and optimizing the internal structure.


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