bluuebunny/crossref_metadata_2025 huggingface dataset:
Electrochemical Immunoassay Strategies for Detection of Bovine Serum Albumin-17beta-Estradiol
Authors: Liu Jianshe
Published: February 2020

The endocrine-disrupting compound 17beta-estradiol (E2) is endogenously produced by all mammalian species. Over the last years, many studies have suggested that E2 are growing concern that even at low concentrations may adversely affect fish, wildlife, ecosystems and possibly human health.

We propose strategies for detection of Bovine serum albumin-17beta-estradiol (BSA-E2) by using CdSe Quantum Dots as electrochemical labels for amplifying signal. BSA-E2 was chosen as a model 17beta-estradiol in this work.

In this model the CdSe QDs were used as labels for amplifying electrochemical signal and were conjugation with secondary anti-17beta-estradiol antibody (anti-E2 antibody) in heterogeneous sandwich immunoassay. Using two-step protocol for conjugation of CdSe QDs and anti-E2 antibody because of antibody contains both carboxylates and amines [1]. In the first step, EDC is used in the presence of sulfer-NHS to activate carboxylates on the CdSe QDs to intermediates sulfer-NHS esters. The second step is activates CdSe QDs by add the anti-E2 antibody solution to be coupled.

Furthermore, Anodic stripping voltammetry (ASV) is a powerful method for the determination of trace heavy metals, based on relatively inexpensive and portable equipment, and its analysis time is much shorter than other methods. Here the Cd2+form acid dissolution step was detected. For this purposed the anti BSA antibody was immobilization Nafion/ITO electrode. The modification surface and subsequently stepwise immobilization was investigated by EIS and AFM.

References

[1] G.T. Hermanson,Bioconjugate Techniques(second ed.)Elsevier, London (2008)

Acknowledgment

National Natural Science Foundation of China (No. 41073060, No. 21377023) Research Fund for the Doctoral Program of Higher Education of China (No. 20100075110010 )
A Novel Tyrosinase Base Biosensor for the Quantification of Antioxidant Capacity: Evaluation on Infusions of Medicinal Plants
Authors: Rodríguez-Sevilla Erika , Ramirez-Silva Maria Teresa , Palomar-Pardavé Manuel , Romero-Romo Mario , Marty Jean Louis , Ibarra-Escutia Pedro
Published: February 2020

The working electrode of screen-printed-type electrodes, SPE, was modified with Tyrosinase enzyme (Tyr) using different immobilization methods namely: entrapment, using water soluble polyvynil alcohol, PVA, cross-linking using glutaraldehyde, GA, and cross-linking using GA and Human Serum Albumin, HAS. The resulting electrodes were named: SPE/Tyr/PVA, SPE/Tyr/GA and SPE/Tyr/ HSA/GA, respectively. All these biosensors were characterized through amperometry, immersed in an aqueous solution containing different catechol concentrations, and EIS techniques. From the amperometric evaluation, the apparent Michaelis-Menten constant, Km´, of each biosensor were evaluated and from the impedance measurements the respective charge transfer resistance, Rct, were assessed. It was found that the biosensor SPE/Tyr/GA has the lowest Km´ (57 ± 7) μM and Rct values. Moreover, this electrode also displays both the lowest detection and quantification limits for catechol quantification, notwithstanding, the highest sensitivity corresponds to the SPE/Tyr/PVA biosensor. Using the SPE/Tyr/GA biosensor, the Trolox Equivalent Antioxidant Capacity (TEAC) was determined for infusions prepared with Mirto (Salvia microphylla), Hierba dulce (Lippia dulcis) and Salve Real (Lippia alba); medicinal plants commonly used in Mexico.
Ion-Selective Electrode Solid Contact Base on Neutral-Carrier Ditiophosphate for Mercury Determination at Nanomolar Levels
Authors: Juarez-Gomez Jorge , Ramirez-Silva Maria Teresa , Perez-Garcia Francisco , Palomar-Pardavé Manuel , Romero-Romo Mario , Rojas-Hernández Alberto
Published: February 2020

Potentiometric studies for ion-selective electrodes solid contact based on neutral carriers that contain in their structure sulphur donor groups and an aliphatic chain is presented, this chain may confer stability to the molecule for the formation of metal complexes. The result was obtaining an ISE, for the potentiometric determination of mercury. This sensor allowed continuous mercury measurements at nanomolar levels within a wide concentration interval (1.0 x 10−9 a 1.0 x 10−1) mol L-1, with a detection limit of (9.1 ± 0.8) x 10−10 mol L-1 and a Nernstian response of (29.8 ± 0.4) mV decade-1. The ISE can be used in the 0 – 6 pH interval; it exhibited a high selectivity toward the mercury ions even in the presence of interferents, and can be used as an indicating electrode during potentiometric mercury titration with EDTA, because it is comparable, within its same class with the commercial electrodes.
Invited: Non-invasive sensing of livestock health parameters
Authors: Mason Alex , Sneddon Jenny
Published: February 2020

Development of the livestock sector at EU and global level is challenging as it puts pressure on the environment as well as animal welfare. Livestock production accounts for over 40% of the overall EU agricultural output – in 2011 EU-27 farmers raised livestock with a total value of €154 billion . Products derived particularly from beef cattle, dairy cattle and small ruminants (i.e. sheep and goats) typically require farmers to graze their animals on grasslands to provide the necessary nutrition for sustainable productivity. For farmers to maintain sustainable livestock production, they must ensure that both livestock and their grazing environments are well managed. This is by no means a trivial task given that animals may be spread over large areas depending on the grazing system employed and geographical location, in addition to a farmer potentially owning many hundreds of animals. Currently farmers have no means to, remotely and in real-time, determine the location, condition and activity of their livestock and control (e.g. movement) of animals is still largely a manual process. The authors are seeking to address all of these issues through the development of a smart integrated sensor system; this paper focuses on one aspect of this system, namely the determination of animal health. A non-invasive electromagnetic wave sensor has been developed for in-situ determination of blood lactate concentration in dairy cows as a rapid indicator health status. It has been tested currently in the laboratory environment, and has been shown to deliver sensitivity to < 1 mmol-1 changes in lactate level over a range of concentrations (0-64 mmol-1) in defibrininated bovine blood through approx. 15mm of cow hide. The further development of this work will undoubtedly bring a step-change in the welfare of livestock across the sector, in addition to helping farmers maintain sustainable output to meet ever increasing pressures to produce.
Alternative Substrate Materials for Impedance Biosensors
Authors: Suni Ian Ivar , Radhakrishnan Rajeswaran
Published: February 2020

Impedance biosensors have been widely studied for applications to biomedicine, environmental monitoring, food, and agriculture. The most common format for AC impedance biosensors involves surface immobilization of an antibody, receptor protein, DNA strand, or other species capable of bio-recognition, and AC impedance detection of the binding event.

One obstacle to application of impedance biosensors is the stability and reproducibility of protein immobilization. This problem is exacerbated by the need for sensor calibration, which is typically accomplished using chaotropic reagents. Most studies of impedance biosensors have employed amide bond formation to Au-thiol self-assembled monolayers for biomolecule immobilization. However, this chemistry is relatively unstable, with the shelf life limited to days to weeks.

Degenerate (highly doped) Si is an attractive alternative substrate material for impedance biosensors. Advantages of degenerate Si include simple and reproducible surface preparation, easy incorporation into ULSI devices, and the greater strength of Si-C bonds (~520 kJ/mole) relative to Au-S bonds (125-150 kJ/mole). Peanut protein Ara h 1 can be detected atop degenerate Si electrodes with a detection limit of < 5 ng/ml. Regeneration of antibody films atop degenerate Si using 0.2 M KSCN and 10 mM HF allows repeated detection of peanut protein Ara h 1 during a 30-day trial. The inclusion of HF is required to periodically remove Si oxide from the substrate. Results will also be presented for impedance biosensing with Ti/TiO2 as the substrate material.
Magnetophoretic Chromatography Technique for the Detection of Pathogenic Bacteria with the Naked Eye
Authors: Kwon Donghoon , Jeon Sangmin
Published: February 2020

INTRODUCTION

Since microorganisms tend to proliferate over time, the detection of pathogenic bacteria at an early stage is crucial for preventing food-borne illnesses. To address these problems, we have developed a novel method for the detection of pathogenic bacteria that uses simple magnetic separation in a precision pipette. After separation of Salmonella bacteria from milk using antibody-conjugated magnetic nanoparticle clusters (MNCs), the Salmonella-containing solution and viscous polymer solution are successively loaded into pipette tip placed above a permanent magnet. The MNCs-Salmonella complexes are attracted to the bottom of the tip whereas most of the free particles are trapped at the interface between the solutions, which is called as magnetophoretic chromatography. Once the separation is completed, the presence of Salmonella bacteria can be determined with the naked eye. The detection limit is 100 cfu/mL, which is comparable to results obtained with light absorption measurements.

RESULT

Fig. 1 shows schematic illustrations and the corresponding optical images of the magnetophoretic chromatography setup before and after the separation of Au/MNC−Salmonella complexes from free Au/MNCs respectively. Fig. 2 shows optical images of the pipette tips after 10 min of magnetophoretic chromatography. As the concentration of Salmonella bacteria increases, the color at the end of the tip becomes dark whereas the color of the interface of the solutions becomes pale. The Au/MNCs-Salmonella complexes become concentrated at the narrow tip of the pipette, so the presence of Salmonella bacteria can be confirmed with the naked eye for concentrations down to 100 cfu/mL.

Conclusion

We have developed a magnetophoretic chromatography separation technique that uses a precision pipette and applied this method to the detection of Salmonella bacteria in milk with the naked eye. Because the experimental set-up requires only a permanent magnet and a precision pipette, the developed method is simple and cost-efficient, which means that it can be used in the rapid on-site detection of bacteria at restaurants, hospitals, and even homes for food safety monitoring. As a result, this assay will play a key role in preventing the outbreak of foodborne diseases caused by microorganisms, especially in developing countries.
Graphene Quantum Dots and Graphene Oxide-Based Biosensors for Detection of Cancer Biomarkers and Heavy Metals
Authors: Wu Nick , Li Ming
Published: February 2020

Generally organic dye molecules are used as both the energy donor and acceptor in fluorescence resonance energy transfer (FRET) systems.1,2 However, organic dyes suffer from photobleaching. Graphene and graphene oxide (GO) were recently developed as both the donor and the acceptor for energy transfer-based fluorescent sensors.3-5 A fluorescent dye to graphene follows the nano-surface energy transfer (NSET) mechanism.

Herein a fluorescent sensor based on the quantum dot (QD)/aptamer-GO complex is constructed in which GO acts an energy acceptor. This sensor is highly sensitive to Pb(II) with a limit of detection of 90 pM. On the other hand, with GO as the energy donor, a fluorescent sensor has also been developed for Hg2+ detection.

In addition, graphene quantum dots have been used as the energy acceptor to build fluorescent sensor for cancer biomarker detection.

This work was financially supported by a NSF grant (CBET-1336205). The resource and facilities used were partially supported by NSF (EPS 1003907) and a Research Challenge Grant from the State of West Virginia (EPS08-01).

REFERENCES AND NOTES

(1) S. K. Cushing, M. Li, F. Huang, N. Q. Wu, Origin of strong excitation wavelength dependent fluorescence of graphene oxide, ACS Nano, 8 (2014), 1002-1013i,

(2) M. Li, H. Gou, I. Al-Ogaidi, N. Q. Wu, Nanostructured sensors for detection of heavy metals: a review, ACS Sustainable Chemistry & Engineering, 1 (2013), 713-723

(3) M. Li, X. Zhou, S. Guo, N. Q. Wu, Detection of lead (II) with a "turn-on" fluorescent biosensor based on energy transfer from CdSe/ZnS quantum dots to graphene oxide, Biosensors and Bioelectronics, 43 (2013), 69-74.

(4) M. Li, X. Zhou, W. Ding, S. Guo, N. Q. Wu, Fluorescent aptamer-functionalized graphene oxide biosensor for label-free detection of Mercury(II), Biosensors and Bioelectronics, 41 (2013), 889-893

(5) I. Al-Ogaidi, H. Gou, Z. P. Aguilar, S. Guo, A. K. Melconian, A. Kareem A. Al-kazaz, F. Meng*, and N. Q. Wu, Detection of the ovarian cancer biomarker CA-125 using chemiluminescence resonance energy transfer to graphene quantum dots, Chemical Communications, 50 (2014), 1344-1346
Development of Minimally Invasive Biosensor for Continuous Glucose Monitoring
Authors: Yasuzawa Mikito , Li Jiang , Hiura Kentaro , Edagawa Kazuaki , Fuchiwaki Yusuke
Published: February 2020

Good control of blood glucose degree is quite important for the prevention of serious diabetes complications onset and progression. Accurate recognition of the blood glucose degree helps the patient to provide appropriate treatments, such as insulin therapy. Recently, implantable glucose sensors for continuous glucose monitoring (CGM) are of significant importance on diabetic health care, since it not only lower the physical and mental load on glucose measurement, but also present continuous glucose trend, which is useful for treatment evaluation. However, since the length of sensor device inserted in skin is about 1 cm, development of lower invasive CGM system is expected for the improvement of diabetic patients quality of life.

In this study, a low invasive patch type glucose sensor, which has sensing region at the tip inside of a tube, was proposed. The schematic illustration of the tip of such glucose sensor is shown in Figure 1. Since the sensing region is at the inside of a fine needle tube, it requires only the sensor tip to be implanted in the tissue for glucose monitoring. In other words, it can be possible to perform as a patch type sensor, which impresses the user as a sticking sensor instead of implanting sensor. Glucose oxidase was immobilized inside the tube using the combination of electrodeposition and electropolymerization technique, which was similar to the procedure proposed by Wilson’s group [1,2]. That is, phosphate buffer solution (pH 7.0) containing GOx and Triton X-100 was first poured inside the tube electrode and applied a potential of 1.3 V (vs Ag/AgCl) for 1 h to form GOx layer on the surface. Phosphate buffer solution containing o-phenylenediamine (o-PD) was next poured inside the tube and a potential of 0.7 V (vs Ag/AgCl) was applied for 15 min to induce the electropolymerization of o-PD. Properties of the obtained sensor were evaluated both by in vitro and in vivo measurements.

Acknowledgment

This study was supported in part by a Grant-in-Aid for Scientific Research (C) No. 24500510 from Japan Society for the Promotion of Sciences (JSPS).

References

[1] N. Matsumoto, X. Chen, G. S. Wilson, Anal Chem, 74, 362 (2002).

[2] X. Chen, N. Matsumoto, Y. Hu, G. S. Wilson, Anal Chem, 74, 368 (2002).
Graphene Synthesis on Electrodeposited Substrates and Its Integration in MEMS for Sensor Applications
Authors: Tocchio Marco , Ieffa Simona , Bernasconi Roberto , Magagnin Luca , Nobili Luca , Carraro Carlo , Maboudian Roya
Published: February 2020

Graphene has become a promising material for many different applications, such as nanoelectronic devices, physical, chemical and biochemical sensors, transparent conductive films, clean energy scavenging and storage devices, and nanocomposite formulation. Recently, gas sensing, as a critical application in intelligent systems, is receiving increasing attention in both industry and academia. Sensing applications using graphene sheets as transducers have experienced a surge of activities in recent years, especially for gas sensing platforms and electrochemical sensing, because of the high electrical conductivity and high surface area of graphene. Despite the significant amount of work on graphene electronic devices such as the field effect transistor, its use in sensors, actuators or micro and nano-electromechanical systems (MEMS/NEMS) in general, is relatively less explored. By combining graphene's electronic and mechanical properties, monolithic sensors can be developed with superior sensitivity. Furthermore, proper functionalization of graphene enables enhanced selectivity. In this work, we investigate the synthesis of graphene by methane decomposition at 1000 °C onto free standing electrodeposited substrates, studying the effects of the electrochemical synthesis onto graphene quality. The growth of good quality graphene layers is also discussed in terms of the role played by grain boundaries and diffusion at the grain boundaries. Results on graphene properties when grown on ruthenium, copper and Ni-Cu alloys are reported, together with the possibility to grow 3D graphene layers on porous substrates, obtained by selective electrochemical de-alloying in the Ni-Cu system. Our results demonstrate the synthesis of graphene on Cu with presence of the D-peak and with the 2D-peak not higher than the G-peak (shifting of the 2D-peak) and on Ru with a high D-peak but with the 2D-peak still higher than the G-peak. The growth of graphene on NiCu is affected by the amount of copper in the alloy: a transition from graphitic to graphenic layers is observed with increasing copper content. Transfer procedures in order to integrate thus-produced graphene layers into MEMS device are presented, including the electrochemical approaches to decorate the graphene sheets with catalytic nanoparticles. The possibility of using this simple approach to develop new transducing materials for sensing applications integrated with a silicon microdevices is demonstrated.
Novel Non-Polarizable Dry Screenprinatable Polymeric Nanocomposite Micro-Sensors for Wearable Devices
Authors: Khosla Ajit
Published: February 2020

This work presents preparation, characterization and electrical properties of a flexible screenpritable conducting nanocomposite polymer which has been prepared by Acoustic Mixing. The prepared nanocomposite consists of plastisol and Silver/Silver chrolide nanoparticles. It is observed that at weight-percentages of above approximately 59 wt-% of Silver/Silver chrolide nanoparticles , and has a resistivity of 1.98 x 10-6 ohm·m. Applications of the prepared nanocomposite in the area of wearable garments and devices will also be discussed [1,2,3,4].

References:

D. Chung, A. Khosla, et al, “Flexible Ag/AgCl electrodes for applications in tissue Electrical Impedance Scanning (EIS)” Journal of The Electrochemical Society, 161 (2) B3071-B3076 (2014)

A. Khosla and B. L. Gray, “Preparation, characterization and micromolding of multi-walled carbon nanotube polydimethylsiloxane conducting nanocomposite polymer”; Materials Letters Volume 63, Issues 13-14, 31 May

2009, Pages 1203-1206.

A. Khosla, B.L. Gray, “CONDUCTIVE ELASTOMERIC MATERIAL AND USES THEREFOR“ US Patent No. 61/113998- Issued.

A. Khosla, and B. L. Gray; “Micropatternable Multifunctional Nanocomposite Polymers for Flexible Soft NEMS and MEMS Applications” ECS Trans. 2012 volume 45, issue 3, 477-494.
Preparation of Glucose Oxidase Immobilized Electrode Using Electrodeposition Procedure and Its Glucose Sensor Properties
Authors: Hiura Kentaro , Li Jiang , Furukawa Shinya , Fuchiwaki Yusuke , Yasuzawa Mikito
Published: February 2020

The importance of glucose determinations for the diagnosis and effective treatment of diabetes has been well recognized. Therefore, much effort has been devoted to developing an effective sensor for the continuous estimation of glucose concentration in subcutaneous tissue [1]. Miniaturization of the sensor device is an important subject, since smaller devices are less invasive, both physically and psychologically. A finer device will excite fewer pain receptors in the skin and will cause less tissue damage and less pain. However, fabrication of finer sensor request precise technique to immobilize enzyme in a specific area. Conventional methods of enzyme immobilization are covalent attachment,cross-linking, hydrogel entrapment, electropolymerized polymer entrapment, and the combination of two or more methods. Among the variety of procedure for the immobilization of enzyme, electropolymerized polymer entrapment is interesting, since the enzyme will be immobilized just at the position where the electricity was passed. Similar to this procedure, Matsumoto et al reported that the layer of enzyme can be formed on the electrode by applying a potential of 1.3 V (vs Ag/AgCl) in the enzyme solution containing a nonionic surfactant such as Triton X-100. Since the obtained enzyme layer was not stable, they formed a electropolymerized polyphenol film in order to improve the stability, which also functioned as a permselective film to eliminate the influence of electroactive species excite in the biological fluid such as ascorbic and uric acids. In this study, glucose oxidase was immobilized using electrodeposition procedure and polymer film was formed to stabilize the enzyme film. Glucose sensor properties of the obtained electrode were investigated using in vitro and in vivo measurements.

1. N. Matsumoto, X. Chen and G. S. Wilson, Anal Chem, 74, 368 (2002).
Electrochemical Characterization of Ion-Sensitive Capacitors with ALD Al2O3 as the Sensitive Dielectric
Authors: Perez Ramos Berni Manolo , Molina Reyes Joel
Published: February 2020

The physical, chemical and electrochemical characterization of sensitive materials used for ion-sensitive capacitive sensors (ISCAPs) has been performed. These sensors were designed with a single-metal level fabrication process (first metal level of an integrated circuit), and include special capacitive features which could help to increase the sensitivity of the devices (through modulation of their flat-band voltage). Additionally, an integrated quasi-reference electrode has been included in the design, thus enabling measurements without using any conventional external electrode. Based on previous results of the chemical and morphological characterization of materials after immersion in buffer solutions, it is expected that these sensors will provide high sensitivity and a stable response for pH measurements in the short-term.
Pitting Corrosion Restraint Mechanism of Aluminum with the Silane Coupling Agent
Authors: Mabuchi Katsumi
Published: February 2020

Conventionally, surface treatment based on the use of chromate conversion layer is efficient for preventing corrosion of metals, but it releases highly toxic Cr(VI) into environment. For this reason, a new surface treatment method using the Cr(III) was developed. This replacement process is based on a corrosion control mechanism by formation of reaction products and oxide that are formed by a base metal dissolving.When this surface treatment method is applied to a thin metal film, there is concern that a base metal film may disappear during this treatment. Thus, this treatment cannot be applied to a thin metal film. Recently, surface treatment using a silane coupling agent such as bis(3-triethoxy Cyril) ethane (C2H5O)3Si(CH2)2Si(OC2H5)3 (BTSE) has evolved as a promising alternative to replace the toxic chromate-based treatments. There are many reports about the improvement in general corrosion resistance of the Al by the silane coupling treatment1)-4). However, the improvement in pitting corrosion resistance by the silane coupling treatment is not necessarily obvious. To improve the pitting-corrosion resistance of thin Al film, this work reports the optimum of the silane coupling treatment.

An Al film was immersed in ethanol solution with several silane coupling agents in 0.5-96h. Polarization curves of the Al film treated by silane coupling agents were measured in 3.5% NaCl solutions. Pitting and general corrosion were evaluated using pitting potential and corrosion current density, respectively. Ten kinds of silane coupling agents that can be divided two major categories, i.e. mono-silyfunctional silanes (‘mono silanes’) and bis-silylfunctional silaned (‘bis silanes’), were used as treatment solutions. Surface observation and surface analysis of Al surface treated silane coupling agents were performed by using AFM, SEM and XPS, respectively.

The difference in corrosion resistance behavior between use of mono silanes and bis silanes is not confirmed. The treatment of Al using a silane agent including the N element does not inhibit general corrosion or pitting corrosion. On the other hand, the treatment of Al by using a silane agent including the O or S element inhibits both general corrosion and pitting corrosion. In this paper, the relationship structure of the silane coupling layer and corrosion resistance is discussed.

Reference

1)Danqing Zhu, Wim J. van Ooji, CORROSON SCIAENCE
45 (2003)2177-2197

2)M. Teo, J. Kim, P.C. Wong, K.A.R. Mitchell, Applied Surface Science, 252, (2005) 1293-1304

3)DANQING ZHU and WIM J. VAN OOJI, J. Adhesion Sci. Technol., Vol. 16, No.9 (2002) 1235-1260

4) A. Frignani, F. Zucchi, G. Trabaneli, V. Grassi, CORROSION SCIENCE, 48 (2006) 2258-2273
Influence of Microstructure and CO2 on the NaCl-Induced Atmospheric Corrosion of Semi-Solid Cast and High Pressure Diecast Mgal Alloys
Authors: Shahabi-Navid Mehrdad , Esmaily Mohsen , Johansson Lars-Gunnar , Cao Yu , Svensson Jan-Erik , Halvarsson Mats
Published: February 2020

The NaCl induced atmospheric corrosion of MgAl alloys AM50 and AZ91 was studied in the laboratory at 95.0% relative humidity (RH) and 22oC. The two alloys were investigated both in semi-solid cast (SSC) and in high pressure diecast (HPDC) states. Exposures were conducted in the presence of 400ppm CO2 and in the absence of CO2. Crystalline corrosion products were identified by X-ray diffraction (XRD). X-ray photoelectron spectroscopy (XPS) was employed to examine the surface film formed in the initial stages of corrosion. Magnesium carbonate and magnesium oxide (oxide/hydroxide) were detected in the top and bottom of the surface film, respectively. Alloy microstructure and corrosion morphology were characterized by scanning electron microscopy (SEM). Corrosion was more localized in CO2-free environment compared with air with 400ppm CO2. The same alloy prepared by SSC and HPDC routes showed different corrosion properties. It is suggested that the influence of casting technology on corrosion is caused by differences in the area fraction and distribution of β-phase.
The Use of 3D-Svet for the Examination of Plasticised PVC Coatings: The Effect of Deformation and UV Irradiation on Barrier Properties
Authors: Searle Justin Royston , Wilson Benjamin Paul , Yliniemi Kirsi , Worsley David A , McMurray Hamilton Neil
Published: February 2020

The 3D-SVET is a valuable technique for the examination of corrosion phenomena on non-planar samples. A bi-functional probe is first used to record topographical data to obtain a surface height map; subsequently this height map is used to retrace the surface, obtaining current density data at a known fixed height. In this work the apparatus was utilized to investigate the effects of forming and irradiation on model plasticized PVC coatings and specifically the influence on the barrier properties of the coating. Samples were prepared via bar casting onto galvanneal steel substrate and then either examined in a planar state or after a bending process that created a 30° deflection from flat. Samples were examined via 3D-SVET either as cast or after irradiation with UV in order to investigate the effects of weathering. In addition, an industrially produced coating that had undergone natural weathering for a period of 17 years in a coastal industry environment was also analyzed as a comparison.

The model study demonstrated that both the planar non-irradiated and the planar irradiated samples retained their coating integrity, with the 3D SVET detecting no corrosion activity during a 24hr immersion study. In contrast, the samples that underwent a forming process showed evidence of a cathodic band of activity that coincided with the peak of the bend. This band increased in activity during the period of immersion, most likely due to the improved oxygen availability at the thinnest part of the coating. Findings from the industrial coating (See Fig 1A-C) showed the presence of numerous penetrative defects and it was found that the majority of the longer lived defects existed within the emboss pattern, coinciding with thinnest part of the coating. Subsequent removal of the industrial coating evidenced the extent of the zinc dissolution that occurred during the samples lifetime.

Figure 1: A) The surface profile of the industrial coating, illustrating the leathergrain emboss pattern within the paint. B) A Surface image of the coating overlaid with the most active anodic areas as measured over 24hrs immersion in 5% NaCl. C) The resulting galvanneal surface post removal of the plastisol coating, illustrating the metal dissolution during the samples life.

.
Storage and Release of Corrosion Inhibitors from Commercial Primers
Authors: Klomjit Pitichon , Buchheit R.
Published: February 2020

Commercial primers are applied on aluminum alloys that are used in aerospace applications to prevent corrosion attack from aggressive environment. These primers contain some effective inhibitors that help combat against corrosion. During field operations, these primers store and release inhibitors to protect the substrate materials. The goal of this study is to characterize storing and releasing behaviors of these commercial primers to better understand rate and mechanism at which inhibitors are released. Three commercial primers are being investigated in this study; 1) Akzo Nobel 10P20-13 High Solid Primer that contains strontium chromate (SrCrO4), 2) Deft 02GN087 (non-chromate), and 3) Hentzen 16708TEP (non-chromate). The primers were coated on a Teflon tape, then stripped off and broken to small pieces. Pieces of primers were exposed to different environments with varied Cl- concentration, temperature, time, and pH. Inductively Coupled Plasmas Mass Spectroscopy (ICP-MS) was used to analyze elements from the solution. Results have shown that SrCrO4 primer release behavior follows power law kinetic. The effect of temperature changes the releasing mechanism of AkzoNobel primer. Chloride seems to promote release rate, and the effect of pH is still under investigation. Deft primer releases a large amount of Ca, but does not seem to be time dependent. Hentzen does not seem to release any soluble constituent to any extent.
Corrosivity Measurements of Singapore and the Effect of Tropical Atmosphere on Corrosion of Different Metals
Authors: Wijesinghe Sudesh Lakshitha , Tan Zixi
Published: February 2020

Atmospheric corrosion is clearly the most noticeable of all corrosion processes. Tremendous amount of economic losses are caused by atmospheric corrosion. Thus it is imperative to know the level of atmosphere’s aggressiveness or in other words “corrosivity”, before anyone designs or plans any corrosion prevention strategy. Corrosivity values were not recorded before in Singapore though those were measured and recorded in other countries.

In the aim of filling this gap, test sites had been established on three locations of Singapore. Thus corrosivity readings were measured and recorded according to ISO 9223:2012 for the first time in Singapore. Both determined and estimated corrosivity values were recorded upon completion of one year exposure of standard metal samples and atmospheric constituents / pollutant measurements respectively. Final objective of this work is to correlate some accelerated cyclic corrosion test parameters with these Singapore atmospheric corrosivity values. Results will be useful for both industrial and research needs in future. A detail discussion together with results will be presented.
Protective Efficiency of the Oil Composition Coatings Against Carbon Steel Atmospheric Corrosion in the SO2 Presence
Authors: Shel Natalia , Vigdorovich Vladimir , Tsygankova Liudmila , Uryadnikov Alexandr
Published: February 2020

The protective properties of the compositions on base of the industrial oil or transformic one and oilsoluble inhibitor IFHAN 29-A (the product of the catalytic interaction between tall oil production waste and higher aliphatic amines) have been studied with respect to carbon steel in the atmosphere containing 0.1 – 10 vol.% SO2 at the different humidity (70 – 100%) and room temperature.

IFHAN 29-A shows the thickening ability with respect to industrial and transformic oils in the 293 – 353K temperature range. It allows to deposit the oil coating films of 20 ± 5 μm thickness on the metal surface. These films provide a protection of carbon steel against atmospheric corrosion in the presence of SO2. A growth of the inhibitor concentration in the oil composition film results a sharp increase of the protective efficiency in the presence of SO2 in comparison with the conditions without SO2. The oil nature doesn’t practically influence on the qualitative and quantitative character of the dependences. Protective efficience of the oil compositions reaches 80%.

Kinetics of the cathodic and anodic processes on steel has been investigated in the 0.5 M NaCl solutions in the presence of SO2. A growth of the SO2 volume concentration in the air phase increases the cathodic limiting diffusion current density in the absence of the protective oil composition film on the electrode surface, but does not practically influnce in the presence of the coating. A dependence of the anodic ionisation rate on the SO2 concentration in the presence of the protective oil composition film has an unmonotonous character.

The observed results are discussed with taking into account an interaction between SO2 and water leading to a formation of the SO2
.H2O hydrate and the [SO2]/[H2SO3] correlation equal to 20 in the aqueous solution.
Evaluation of Atmospheric Corrosivity Indexes in the City of Tuxpan Veracruz
Authors: Rosas Pérez Miguel Ángel , Gallardo Castán Ernesto , Lugo Islas Gabriela , Galicia Badillo Aurora , Ramírez Reyes José Luis , García Navarro Norma , Pérez Téllez Juan , Mercado Bahena Iris Graciela
Published: February 2020

In this work we studied the effect of the seasons using aluminum wire samples on copper screw, plastic and carbon steel in order to determine corrosivity indices to assess the type of atmosphere (marine, industrial, urban and rural) that predominates in Tuxpan. They found that rates of aluminum corrosivity on steel screw used to assess the industrial atmosphere is within allowable levels in the four seasons of the year, in the case of urban-rural atmosphere in the spring season, the corrosivity index is higher than the level allowed within the regulations, in the autumn season is within the level permitted by the standard, and the summer and winter seasons are below the minimum level. Finally, in the spring and winter seasons indexes marine corrosivity of the atmosphere are within permitted levels, while for the summer and fall seasons corrosivity indices are minimal. It is considered that the effect of weather conditions dramatically affect the galvanic couple made up of aluminum and each screw in different atmospheres throughout the year so that must be suitably selected metallic materials for the construction of handrails, screens and windows in the study region to the aggressiveness of the marine atmosphere.
Corrosion Inhibitors in the Development of Hybrid-Smart-Nanostructured Coatings
Authors: Zambrano-Rengel Griselda Elena , Uruchurtu Jorge , Menchaca Carmina , Guardián Tapia René
Published: February 2020

Results of the corrosion behavior of inhibitors contained inside of ceramic nanoparticles as part of the development of a hybrid smart coating used to protect pieces of copper used in the manufacture of historical pieces belonging to the cultural heritage .

The kaolin is a waste product from the ceramic industry with porous properties that facilitate the process of absorption of chemicals inhibitors of the corrosion process as benzotriazole (BTA) and copper sulfate pentahydrate (CuSO4.5H2O). The optimal efficiency of the inhibitors was determined using gravimetric methods and using potentiodynamic polarization . The adsorption of the inhibitors is reached preparing several mixtures of acetone and distilled water saturated with inhibitor through a process of stirring for 24 hours . Copper samples were coated with a commercial brush No. 10 using epoxy resin mixed with 2.5 %, 5% and 10 % of kaolin nanoparticles doped with inhibitor. The system was characterized using electrochemical techniques like electrochemical impedance spectroscopy (EIS), potentiodynamic polarization methods and electrochemical noise spectroscopy (EN) to determine the efficiency of the new structured kaolin particles into the coating. The electrolytic solution for the application of electrochemical techniques was a mixture of NaCl. and (NH4)2SO4, used to study atmospheric corrosion; simulating contaminated atmospheres with chlorides and sulfates in urban environments. The techniques used for materials characterization were scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) like a great complement to the complete study of the system.
Development of Representative Tests to Quantify the Susceptibility to Stress Corrosion Cracking of α,β’-Brass Used for Gas Transfer Devices
Authors: Berne Clément , Andrieu Eric , Reby Jean , Sobrino Jean-Michel , Blanc Christine
Published: February 2020

Stress corrosion cracking (SCC) is believed to be the principal cause of the cracks observed in brass components used in gas distribution network. In this framework, it is of interest to develop accelerated tests to determine the SCC susceptibility of the brass used in the gas transfer valves. To be representative and reliable, a reference test has to reproduce most of the damages observed on network components after break-up during operation. The present study aimed at developing SCC equipment and experimental protocol leading to a relevant evaluation of the SCC susceptibility of α,β’-brass.

The specimens tested, corresponding to α,β’-brass CuZn40Pb2 (CW617N), were machined from stamping rods used to manufacture gas transfer valves. The accelerated tests were performed in NaNO3 solution selected with reference to research on α-brass (1). The first step of the study corresponded to develop a SCC cell and an adequate experimental protocol, which enable to apply, control and measure specific conditions (load, potential, environment…) leading to various SCC damages; the second step was to compare the SCC damage developed after the accelerated tests to that observed on network components after break-up during operation. The goal was to determine the best parameters for the accelerated tests leading to a SCC damage similar to that observed in service.

Results correspond to the design of the SCC cell developed and the methodology used to validate the applied conditions, and the measurements performed through SCC device. Furthermore, SCC damage developed after the tests was studied on the basis of crack characterisation, quantification of the dissolution process and chemical analyses of the corroded samples. Discussion focuses on the validity and the predictive nature of the test, linked to environment and load levels expected in normal condition of use of brass network components (2) (3). The influence of the manufacturing of brass network components on the SCC susceptibility (modifications in microstructure, work hardening and residual stresses) will be discussed and, in this way, prospects will be presented.

1. S.A. Fernandez and M.G. Alvarez, Corros. Sci.,
53, 82 (2011).

2. C. Mapelli, A. Gruttaduaria and M. Bellogini, Eng. Fail. Anal.,
17, 431 (2010).

3. C. Mapelli, D. Mombelli, S. Barella and A. Gruttadauria, Eng. Fail. Anal.,
27, 141 (2013).
Electrochemical Impedance Response of Zn Under Anodic Polarization in Simulated Concrete Solution
Authors: Garnica-Rodríguez Armando , Rodriguez-Gomez Francisco Javier
Published: February 2020

An understanding of the corrosion behaviour of the zinc alloy coating when placed in concrete and the characteristics of the corrosion products so formed is fundamental to a full appreciation of the corrosion protection afforded by the galvanizing of reinforcement. Pure Zn was chosen because it simulates well the behaviour of galvanized steel, yielding more reproducible results. The aim of this study was to analyze the electrochemical behaviour of pure Zn in Ca(OH)2 saturated solution (simulating the pore solution of concrete) by means of electrochemical impedance spectroscopy measurements under potentiodynamic anodic polarization tests and scanning electron microscopy. Samples used in this work were zinc (99%) alloy, high-grade reagents and distilled water were used to make the solution of saturated Ca(OH)2, anodic polarization and impedance experiments were carried out on a Biologic SP-300 potentiostat. Before the electrochemical tests the specimens are subjected to an exposure of 1 hour in the test solution, the anodic potential scan (0.1 mV s-1) was performed without stirring the solution, starting from the rest potential (Ecorr) and scanning in the anodic direction to 800 mV and 60 mV, during the scanning of anodic polarization from rest potential to 60 mV under a polarization of 10, 20, 30, 40, 50 and 60 mV, the impedance was measured with a sinus amplitude of 10 mV in a frequency range from 200 kHz to 100 mHz. The impedance spectrum shows changes both shape and magnitude indicating more than one process to take place on the surface of zinc, duo to the gradual formation of two semicircles with the increment of potential. (fig.1) These studies are expected to provide technique for development of a protective passive layer on galvanized coatings prior to their embedding in concrete.
Micro-Arc Oxidation Treatments on Zn
Authors: Veys-Renaux Delphine , Guessoum Khadoudj , Rocca Emmanuel
Published: February 2020

Micro-arc oxidation has been a hot topic in the field of surface treatment of aluminum, magnesium and titanium for about twenty years. It consists in a high-voltage oxidation beyond the dielectric breakdown occurring at the interface metal/oxide/electrolyte. Due to the high temperature reached in the resulting plasma, the grown coatings are dry ceramic layers, exhibiting interesting corrosion and wear resistance. This process is generally performed in alkaline media containing additives favoring both the growth rate and the corrosion resistance of the coated materials such as aluminates and silicates. This original paper focuses on the study of micro-arc treatments performed on zinc [1], which could lengthen the service life of sacrificial anodes.

An electrochemical study during the anodizing process revealed that the formation of the first stable insulating layer necessary to reach the dielectric breakdown (and therefore to initiate the sparks) is in competition with the dissolution of zinc. Therefore, beyond a maximum value of pH, starting with the micro-arc regime is no more possible. On the other hand, the addition of silicates or aluminates to the reference electrolytic bath (KOH 0.05 M) facilitates the occurrence of the sparking initiation: around 200 V in KOH 0.05 M, around 150 V with aluminates 0.05 M, around 100 V with silicates 0.05 M.

Post-treatment characterizations of the treated materials performed by FEG-SEM observations coupled with EDX analyses showed that the thickness, the morphology and the composition of the coatings highly depend on the composition of the electrolytic bath.

In terms of corrosion resistance, open-circuit potential measurements, potentiodynamic polarizations and electrochemical impedance spectroscopy measurements were performed in NaCl 0.1 M and showed a very slight improvement of the performances of the treated materials regarding an untreated one since the obtained coatings are cracked and dusty.

[1] TR. Tan, JR. Cheng, JH.Wang, JG Duh, HC. Shih, Surf. Coat. Tech 110, 194-199 (1998)
Electrochemical and Microstructural Study of 18th Century Cannon Ball
Authors: Mortera-Merino Juvencio , Galvan-Martínez Ricardo , Orozco-Cruz Ricardo
Published: February 2020

The main degradation phenomena that affect the metallic cultural heritage are the corrosion reactions with its environment: the burial soil, the outdoor atmosphere or the indoor environment of the museum, display cases or storage. The best way to avoid, or at least delay, such degradation is through preventive conservation. (1)

The conservation and restoration of archaeological metals is one of the most complex conservation issues. Therefore, conservators usually employ the most advanced techniques, with the purpose of obtaining positive results for the preservation of the objects. (2-3)

Nowadays, electrochemical techniques are provided with control devices, such as potentiostatic control and could be considered again as a very valuable option, in combination with traditional and vanguard techniques, to recover the archaeological metallic heritage.(4)

The objective of this work is to show how electrochemical measurements and microstructural characterization can be used as an efficient tool to contribute to the diagnosis of the conservation state of metallic artefacts. In the case of the cannon ball, In San Juan de Ulua Fortress, stationary electrochemical measurements are able to characterise the allowable electrochemical effect of thick corrosion layer on the corrosion rate of metal but are not sufficient to give a complete diagnosis.

The electrochemical behavior of a cannon ball has been studied in two media: 0.01 M sodium borate and 1M sodium chloride. Techniques used include potential measurements as function of time, linear polarization resitance, potentiodynamic polarization curves and electrochemical impedance spectroscopy.

These techniques were carried out on cannon ball fragment, in order to relate microstructural aspects with functionality, manufacturing technology of the piece. Metallographic characterization was performed by optical microscopy and scanning electron microscopy, and chemical analysis by energy dispersive X-ray spectrometry. The results allowed determining that the piece was of lamellar grey iron. (5-7)

The obtained data suggest a relationship between alloy composition and electrochemical properties of the material.
EIS Evaluation of Cefalotine as Corrosion Inhibitor for API 5L X52 Steel Immersed in Acid Medium. Effect of [Cefalotine], Hydrodynamic Conditions, Temperature and Immersion Times
Authors: Aldana-González Jorge , Espinoza-Vázquez Araceli , Romero-Romo Mario Alberto , Ramirez-Silva Maria Teresa , Palomar-Pardavé Manuel
Published: February 2020

The corrosion behavior of pipeline steel grade API 5L X52 immersed in 1M HCl aqueous solution in the presence and absence of cefalotine, was evaluated using EIS and a rotating disk electrode. The effect of different experimental conditions namely: Cefalotine concentration, electrode rotation speed, temperature and immersion times on the corrosion inhibition efficiency (IE) of Cefalotine, were evaluated. It is shown that at stagnant conditions (0 rpm), the IE increased with inhibitor concentration, Fig. 1, reaching a value of ca. 87% at 25 ppm and 89% at 200 ppm. When the steel working electrode rotation speed was varied, it was found that for [Cefalotine] ≥ 25 ppm, the IE reached a maximum value, ca. 85%, at 40 rpm, however, it diminished to ca. 75% when the electrode rotation speed reached 1000 rpm. Furthermore, when the temperature of the corrosive media was increased from 25 to 45 °C, at stagnant conditions with 200 ppm cefalotine, the IE values remain to ca. ~80%. For stagnant conditions, 50 ppm cefalotine and 25 °C, an IE greater that 94% was found for the inhibitor even after 336 exposure hours to the corrosive media.