Effect of passivation on chloride concentration threshold of steel reinforcement corrosion

2017 ◽  
Vol 64 (6) ◽  
pp. 588-598 ◽  
Author(s):  
Nora Bouzeghaia ◽  
Abdelkader Mihi ◽  
Abdelkarim Aït-Mokhtar ◽  
Mahieddine Naoun
Keyword(s):  
Steel Surface ◽  
Chloride Concentration ◽  
Passive Layer ◽  
Ion Concentration ◽  
Threshold Values ◽  
Content Type ◽  
Corrosion Initiation ◽  
Nacl Concentration ◽  
Passivation Time ◽  
Concentration Threshold

Purpose When concrete is manufactured, it can be instantaneously contaminated by chloride (Cl−) ions or later by their intrusion from the environment. This work aims to study the electrochemical behavior of the passive layer formed on the reinforcing steel surface in the presence of the same Cl− ion concentration, with and without passivation time. This will, undoubtedly, affect the corrosion threshold values thereafter. Design/methodology/approach Electrochemical polarizations were carried out in two concrete pore solutions. The surfaces of samples immersed for 255 days in saturated Ca(OH)2 solution were examined with optical and scanning electron microscopy and Raman microspectroscopy. Findings Cl− ion origins in reinforced concrete lead to different values of corrosion thresholds. The passive layer behaves like a physicochemical barrier, and corrosion occurs at higher NaCl concentration thresholds. The formed passive film on the steel surface shows differences in the chemical composition and the morphology. The results show a rich presence of hematite. Maghemite, lepidocrocite, akaganeite and goethite are also present in much lower concentrations. The Cl− ion presence in fresh concrete at the beginning of the manufacture harms the good formation and the good stability of these oxides, leading to corrosion initiation. Originality/value This study contributes to a better understanding of the passive layer role, not only in reducing the corrosion rate value but also in reconsidering new Cl− ion corrosion threshold values.

scholarly journals How Sodium Chloride Concentration in the Nutrient Solution Influences the Mineral Composition of Tomato Leaves and Fruits

HortScience ◽  
2009 ◽  
Vol 44 (3) ◽  
pp. 707-711 ◽  
Author(s):  
Francesco Giuffrida ◽  
Marianna Martorana ◽  
Cherubino Leonardi
Keyword(s):  
Sodium Chloride ◽  
Nutrient Solution ◽  
Chloride Concentration ◽  
Linear Increase ◽  
Ion Concentration ◽  
High Concentration ◽  
Tomato Plants ◽  
Nacl Concentration ◽  
Electrical Conductivities ◽  
Linear Decline

Tomato plants (Solanum lycopersicum L. cv. Durinta) were grown in an open soilless system to evaluate the effects of sodium chloride (NaCl) concentration in the nutrient solution on the ion compositions in plant tissues. The treatments were defined by a factorial combination of five NaCl concentrations and three leaves position/age and two fruits' position. Seedlings were transplanted in perlite and, 7 days after transplanting, five salinity treatments were imposed by adding 7, 21, 37, 49, or 64 mm of NaCl to the nutrient solutions; the final electrical conductivities were: 2.7, 4.5, 6.0, 7.5, and 8.6 dS·m−1, respectively. Increased salinity in the nutrient solution resulted in a reduction in tomato dry matter (from 534 to 375 g per plant) and in a linear increase in sodium (from 0.37% to 1.39%) and chloride (from 1.75% to 5.73%) in the leaves as well as in the fruit tissues (from 0.08% to 0.26% for sodium and from 0.63% to 1.34% for chloride). Leaf under the first cluster showed higher levels of sodium (+54%) and chloride (+32%) than leaf under the fifth cluster and old leaf accumulated more sodium (+15%) and chloride (+25%) than younger ones. The exposure of the tomato plants to increasing salinity resulted in a linear decline in nitrate (from 1.21% to 0.50%), total nitrogen (from 3.31% to 3.03%), sulphate (from 3.71% to 3.12%), and potassium leaves (from 2.76% to 1.51%); the potassium reduction was more evident in younger leaves than in older ones. All macronutrients, except calcium, decreased in the fruit tissues with increasing NaCl concentration in the nutrient solution. However, for phosphate, the reduction of the ion concentration was evident only in the fruit from the fifth cluster (–35%). The position of the fruit on the plant significantly affected the concentration of ion, which was higher for all determined ions in the fruit of the first truss. The levels of Na+ and Cl– found in the plant tissue seem to confirm the hypothesis that the plant dry biomass reduction may also be traced to the toxicity of these ions as a consequence of this high concentration. On the other hand, although generally influenced by antagonism with sodium and chloride, the amount of main macronutrients did not reach deficiency levels that influenced the growth processes, except in the case of potassium.

scholarly journals A Novel Testing Method for Examining Corrosion Behavior of Reinforcing Steel in Simulated Concrete Pore Solutions

Materials ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 5327
Author(s):  
Yanru Li ◽  
Jiazhao Liu ◽  
Zhijun Dong ◽  
Shaobang Xing ◽  
Yajun Lv ◽  
...  
Keyword(s):  
Corrosion Behavior ◽  
Ph Value ◽  
Steel Wire ◽  
Reduction Rate ◽  
Chloride Concentration ◽  
Corrosion Initiation ◽  
Testing Method ◽  
Cross Section Area ◽  
Section Area ◽  
Passivation Time

In this paper, a new mechanical-based experimental method is proposed to determine the corrosion initiation and subsequent corrosion behavior of steel in simulated concrete pore solutions. The proposed experiment is used to investigate the corrosion of the steel wire under various different conditions and to examine the effects of pre-stress level in steel wire, passivation time of steel wire, composition and concentration of simulated concrete pore solution on the corrosion initiation, and subsequent corrosion development in the steel wire. The experimental results show that the reduction rate of the cross-section area of the steel wire increases with the increase of chloride concentration or decrease of pH value in the solution. However, for the case where the chloride concentration is high and the pH value is low, there is a slight decrease in the corrosion rate due to the coating function of the corrosion products surrounding the wire.

scholarly journals Characterization of Virus Adsorption by Using DEAE-Sepharose and Octyl-Sepharose

2002 ◽  
Vol 68 (8) ◽  
pp. 3965-3968 ◽  
Author(s):  
Patricia A. Shields ◽  
Samuel R. Farrah
Keyword(s):  
Sodium Chloride ◽  
Electrostatic Interactions ◽  
Hydrophobic Interactions ◽  
Chloride Concentration ◽  
Sodium Chloride Concentration ◽  
Virus Adsorption ◽  
Nacl Concentration

ABSTRACT Viruses were characterized by their adsorption to DEAE-Sepharose or by their elution from octyl-Sepharose by using buffered solutions of sodium chloride with different ionic strengths. Viruses whose adsorption to DEAE-Sepharose was reduced most rapidly by an increase in the sodium chloride concentration were considered to have the weakest electrostatic interactions with the solids; these viruses included MS2, E1, and φX174. Viruses whose adsorption to DEAE-Sepharose was reduced least rapidly were considered to have the strongest electrostatic interactions with the column; these viruses included P1, T4, T2, and E5. All of the viruses studied adsorbed to octyl-Sepharose in the presence of 4 M NaCl. Viruses that were eluted most rapidly following a decrease in the concentration of NaCl were considered to have the weakest hydrophobic interactions with the column; these viruses included φX174, CB4, and E1. Viruses that were eluted least rapidly from the columns after the NaCl concentration was decreased were considered to have the strongest hydrophobic interactions with the column; these viruses included f2, MS2, and E5.

scholarly journals Effects of Fe+2 and Fe+3 in Pretreatment and Leaching on a Mixed Copper Ore in Chloride Media

Metals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 866
Author(s):  
María E. Taboada ◽  
Pía C. Hernández ◽  
Aldo P. Padilla ◽  
Nathalie E. Jamett ◽  
Teófilo A. Graber
Keyword(s):  
Chloride Concentration ◽  
Solution Concentration ◽  
Copper Extraction ◽  
Curing Time ◽  
Ferrous Ions ◽  
Copper Ore ◽  
Second Stage ◽  
Acid Consumption ◽  
Nacl Concentration ◽  
Leaching Solution

A study of the pretreatment stage and subsequent leaching of a mixed copper ore with different chloride solutions containing iron was carried out. The first stage considered pretreatment tests to decide the best conditions. Two levels of each factor were analyzed, 20 and 50 kg/t of NaCl, 17 and 25 kg/t of H2SO4, 0 and 25 kg/t of Fe2(SO4)3·9.2H2O, 0 and 25 kg/t of Fe2SO4·7H2O, and a curing time of 15 and 30 days. The results showed a significant effect of NaCl and curing time on the extraction, and less effect was found with the variation of acid and iron salts. The second stage included column leaching using a solution with 0.5 g/L of Cu+2, 80 g/L of Cl−, 10 g/L of H2SO4, and variable concentrations of ferric and ferrous ions (0 and 2 g/L). The best copper extraction of 80.2% was found considering a pretreatment of 30 days, 25 kg/t of H2SO4, 50 kg/t of NaCl, and a leaching solution concentration described previously with 2 g/L of Fe+2. The results showed the leaching of all copper oxide species and 20% of the copper sulfide species. In addition, there was a reduction in the acid consumption as the resting time increases. Furthermore, to evaluate a possible decrease in time and acid in pretreatment and chloride in leaching, tests including 10 and 25 kg/t of H2SO4 and 1, 15, and 30 days of curing and a diminution of the NaCl concentration to 20 g/L (content from seawater) were executed. The results showed a significant effect on curing time below 15 days. Furthermore, the slight influence of the decrease of acid on copper extraction gives cost reduction opportunities. The diminution of chloride concentration (80 to 20 g/L) in leaching solution decreases the extraction from 79% to 66.5%. Finally, the Mellado leaching kinetic model was successfully implemented.

scholarly journals Reversing GABA polarity corrects synaptic physiology and behavioural deficits in young adolescent Syngap1+/- mice

2021 ◽  
Author(s):  
Vijaya Verma ◽  
MJ Vijay Kumar ◽  
Kavita Sharma ◽  
Sridhar Rajaram ◽  
Ravi Muddashetty ◽  
...  
Keyword(s):  
Small Molecule ◽  
Intraperitoneal Administration ◽  
Chloride Concentration ◽  
Reversal Potential ◽  
Autism Spectrum ◽  
Ion Concentration ◽  
Pharmacological Intervention ◽  
Subsequent Increase ◽  
Intracellular Chloride ◽  
Gabaergic Synapses

Abstract Haploinsufficiency in SYNGAP1 is implicated in Intellectual Disability (ID) and Autism Spectrum disorder (ASD) and affects the maturation of dendritic spines. The abnormal spine development has been suggested to cause disbalance of excitatory and inhibitory (E/I) neurotransmission at distinct developmental periods. In addition, E/I imbalances in Syngap1+/- mice might be due to abnormalities in K+-Cl- co-transporter function (NKCC1, KCC2), in a similar manner as in the murine models of Fragile-X and Rett syndromes. To study whether an altered intracellular chloride ion concentration represents an underlying mechanism of altered function of GABAergic synapses in Dentate Gyrus Granule Cells of Syngap1+/- recordings were performed at different developmental stages of the mice. We observed that neurons at P14-15 of Syngap1+/- mice had depolarised membrane potential and a decreased Cl- reversal potential. The KCC2 expression was decreased compared to Wild-type (WT) mice at P14-15. Furtherly, the small molecule GSK-3β inhibitor, 6-bromoindirubin-3`-oxime (6BIO), was tested in an attempt to restore the function of GABAergic synapses. We discovered that intraperitoneal administration of 6BIO during the critical period or young adolescents normalized an altered E/I balance, the deficits of synaptic transmission, and behavioral performance like social novelty, anxiety, and memory of the Syngap1+/- mice. In summary, altered functionality of GABAergic synapses in Syngap1+/- mice is based on a reduced KCC2 expression and a subsequent increase in the intracellular chloride concentration that can be counteracted by the small molecule 6BIO. The 6BIO sufficiently restored cognitive, emotional, and social symptoms by pharmacological intervention, particularly, in adulthood.

Electrochemical behaviour of acetyl G as corrosion inhibitor for mild steel in acid medium

2015 ◽  
Vol 44 (6) ◽  
pp. 371-378 ◽  
Author(s):  
Y. Sangeetha ◽  
S. Meenakshi ◽  
C. Sairam Sundaram
Keyword(s):  
Mild Steel ◽  
Corrosion Inhibitor ◽  
Acid Medium ◽  
Steel Surface ◽  
Inhibition Efficiency ◽  
Electrochemical Impedance ◽  
Electrochemical Behaviour ◽  
Green Inhibitor ◽  
Content Type ◽  
Mild Steel Surface

Purpose – The purpose of this paper is to develop an eco-friendly corrosion inhibitor for mild steel in 1 M HCl. Design/methodology/approach – A pharmaceutical drug acetyl G was investigated for its corrosion inhibition efficiency using weight loss method, potentiodynamic polarisation and electrochemical impedance spectroscopy. Findings – The inhibition efficiency increased with increase in inhibitor concentration. Results from polarisation studies revealed mixed type of inhibition. Impedance studies, scanning electron microscopy and Fourier transform spectroscopy confirm the adsorption of inhibitor on the mild steel surface. Research limitations/implications – The drug acetyl G has sulphur and nitrogen atoms which effectively block the corrosion of mild steel and is non-toxic and has good inhibition efficiency. Practical implications – This method provides an excellent, non-toxic and cost-effective material as a corrosion inhibitor for mild steel in acid medium. Originality/value – Application of this drug as a corrosion inhibitor has not been reported yet in the literature. Replacing the organic inhibitors, this green inhibitor shows excellent inhibition efficiency. This is adsorbed excellently on the mild steel surface due to the presence of long chain and hetero atoms. Thus, the drug retards the corrosion reaction.

The effect of non-ionic surfactant on the internal corrosion for X52 steel in extra-heavy crude oil-in-water emulsions

2018 ◽  
Vol 65 (3) ◽  
pp. 234-248 ◽  
Author(s):  
L.M. Quej-Ake ◽  
A. Contreras ◽  
Jorge Aburto
Keyword(s):  
Crude Oil ◽  
Steel Surface ◽  
Corrosion Process ◽  
Ionic Surfactant ◽  
Heavy Crude Oil ◽  
Content Type ◽  
Oil In Water ◽  
X52 Steel ◽  
Emulsion Systems ◽  
Heavy Crude

Purpose The purpose of this research is to study different extra-heavy crude oil-in-water emulsions that can be found in practice for corrosion process of X52 steel adding 60 mg.L-1 of non-ionic surfactant and a corrosion inhibitor (CI). Electrochemical impedance spectroscopy and Tafel plots are carried out. Thus, Bode-modulus and Bode-phase angle plots are discussed. Adsorption isotherms obtained from corrosion rate (CR) values are taken into account. Design/methodology/approach Two-electrode arrangement is used to characterize the pseudo-capacitance values for X52 steel exposed to water and crude oil phases, mainly. Electrochemical evaluations for X52 steel exposed to extra-heavy crude oil-in-water emulsions are recorded in a conventional three-electrode cell to study the corrosion process as was documented in detail by Quej-Ake et al. (2015). Therefore, all electrodes are placed as close as possible to eliminate the iR-drop. Findings Pseudo-capacitance analysis shows that X52 steel immersed in oilfield produced water was more susceptible to corrosion than that immersed in ocean water solution and extra-heavy crude oil phase. After being analyzed, the X52 steel surface coverage and adsorption process for surfactant and CI could be concluded that surfactant could protect the metal surface. In a coalescence extra-heavy crude oil-in-water emulsion, the water medium generated a new solution that was more corrosive than the original water phase. Wash crude oil process was provoked in emulsion systems to sweep up the salts, mainly. Thus, corrosive species that can be recovered inside extra-heavy crude oil may appear, and in turn a new more corrosive solution could be obtained. Taking into account the straight line obtained in Bode-modulus plot for X52 exposed to extra-heavy crude oil, it is possible to point out that the negative value of the slope or R2 can be related to a coefficient (Jorcin et al., 2006). It is important to mention that electrochemical responses for X52 steel exposed to extra-heavy crude oil-in-water under coalescence emulsions revealed that corrosion and diffusion processes exist. Therefore, a possible good inhibitor is surfactant in emulsion systems. Originality/value CR and anodic and cathodic slopes suggest that the surfactant acted as mixed CI. Of these, susceptible anodic (MnS and perlite or cementite) and cathodic (ferrite) sites on steel surface could be affected, due to which physicochemical adsorption could happen by using electrochemical parameters analysis. Thus, no stable emulsions should be taken into account for extra-heavy crude oil transportation, because corrosion problems in atmospheric distillation process of the crude oil due to stable emulsion cannot be easily separated. In this manner, coalescent emulsions are more adequate for transporting extra-heavy crude oil because low energy to separate the water media is required.

Integrated solid-state wearable sweat sensor system for sodium and potassium ion concentration detection

Sensor Review ◽  
2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Haowei Zhang ◽  
Lili Sun ◽  
Chengli Song ◽  
Ying Liu ◽  
Xueting Xuan ◽  
...  
Keyword(s):  
Solid State ◽  
Real Time ◽  
Ion Concentration ◽  
Sensor System ◽  
Linear Potential ◽  
Sensor Systems ◽  
Electrode Arrays ◽  
Content Type ◽  
Sensing Applications ◽  
High Degree

Purpose Design, fabricate and evaluate all-solid-state wearable sensor systems that can monitor ion concentrations in human sweat to provide real time health analysis and disease diagnosis capabilities. Design/methodology/approach A human health monitoring system includes disposable customized flexible electrode array and a compact signal transmission-processing electronic unit. Findings Patterned rGO (reduced-graphene oxide) layers can replace traditional metal electrodes for the fabrication of free-standing all solid film sensors to provide improved flexibility, sensitivity, selectivity, and stability in ion concentration monitoring. Electrochemical measurements show the open circuit potential of current selective electrodes exhibit near Nernst responses versus Na+ and K+ ion concentration in sweat. These signals show great stability during a typical measurement period of 3 weeks. Sensor performances evaluated through real time measurements on human subjects show strong correlations between subject activity and sweating levels, confirming high degree of robustness, sensitivity, reliability and practicality of current sensor systems. Originality/value In improving flexibility, stability and interfacial coherency of chemical sensor arrays, rGO films have been the developed as a high-performance alternative to conventional electrode with significant cost and processing complexity reduction. rGO supported solid state electrode arrays have been found to have linear potential response versus ion concentration, suitable for electrochemical sensing applications. Current sweat sensor system has a high degree of integration, including electrode arrays, signal processing circuits, and data visualization interfaces.

The behavioral analysis of choice difficulty states during clothing online shopping

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Yumiao Chen ◽  
Zhongliang Yang
Keyword(s):  
Online Shopping ◽  
Research Work ◽  
Behavioral Analysis ◽  
Behavioral Performance ◽  
Choice Overload ◽  
Threshold Values ◽  
Content Type ◽  
Behavioral Indicators ◽  
Reported Study ◽  
Practical Implications

PurposeChoice overload in e-commerce induces choice difficulty, which is detrimental to shopping decision-making. The purpose of this paper is to provide relatively simple and effective methods and indicators to detect and assess the choice difficulty states of customers during clothing online shopping.Design/methodology/approachIn order to find out the behavioral performance of choice difficulty states during clothing online shopping, the authors performed the following steps: at first, the authors conducted an experiment to record the videos of the purchasing process during clothing online shopping. Then, the authors carried out the behavioral analysis of customers, correlating each behavioral index to choice difficulty states.FindingsThe results of the behavioral analysis in this study have indicated that three types of behavior were significantly correlated to the choice difficulty states of customers.Practical implicationsIt is expected that it would be possible to use the threshold values of behavioral indicators to determine whether and when the customer is suffering from choice phobia disorder. Based on the findings, a recommender system with timely interventions to help customers with choice difficulty to make shopping decisions will be developed in the future.Originality/valueThis is the first reported study that explores the possibility of using behavioral indicators to detect choice difficulty, which will remain helpful to the scientific community to start further customer-centered research work and development of clothing online shopping.

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