scholarly journals Chemical, electrochemical and tribological study of various olive oils and their behaviour on steel

Chemija ◽  
2018 ◽  
Vol 29 (1) ◽  
Author(s):  
Henrikas Cesiulis ◽  
Albinas Žilinskas ◽  
Juozas Padgurskas ◽  
Raimondas Kreivaitis ◽  
Raimundas Rukuiža
Keyword(s):  
Fatty Acids ◽  
Chemical Composition ◽  
Electrochemical Impedance ◽  
Oxidation Stability ◽  
13C Nmr Spectroscopy ◽  
Mean Values ◽  
Olive Oils ◽  
Angle Measurements ◽  
Contact Angle Measurements ◽  
Electrochemical Impedance Spectroscopy Data

The influence of different chemical composition and physical properties of olive oils, produced from various districts in Morocco with various acidic numbers (from 1.76 to 18.01), on their tribological performance and corrosion protection has been investigated. The chemical composition was determined by means of IR, 1H and 13C NMR spectroscopy. The investigated olive oils show small quantitative and qualitative differences between each other (the amount of free fatty acids and the composition of fatty acids in triglycerides). The spectroscopic data let us unambiguously determine in general that the main fatty acids in oils are saturated palmitic and/or stearic acids, unsaturated oleic and linoleic acids except linolenic acid. The oxidation stability of oils was estimated. The contact angle measurements and electrochemical impedance spectroscopy data show that all films of olive oils on the surfaces of steels are porous; therefore, the values of corrosion inhibition efficiency are relatively low and ranged from 57 to 75%. The variations of friction coefficients and their mean values, the wear of steel covered by olive oils were estimated. The oils with the highest oxidation stability also show better lubricating properties.

Zwitterionic molecule layer for inhibiting microbial corrosion of copper alloy

2018 ◽  
Vol 65 (1) ◽  
pp. 46-52
Author(s):  
Fengling Xu ◽  
Zhenghui Qiu ◽  
Ri Qiu ◽  
Jiadong Yang ◽  
Cunguo Lin
Keyword(s):  
Electrochemical Impedance ◽  
Chemical Vapor ◽  
Attenuated Total Reflectance ◽  
Microbial Corrosion ◽  
Content Type ◽  
Sulfate Reducing ◽  
Angle Measurements ◽  
Static Contact ◽  
Contact Angle Measurements ◽  
Reducing Bacteria

Purpose For mitigating biocorrosion induced by sulfate-reducing bacteria (SRB) in seawater, the zwitterionic molecule layer (ZML) of poly (sulfobetaine methacrylate) is grafted onto B10 surface by chemical vapor deposition and surface-initiated atom transfer radical polymerization. Design/methodology/approach Energy-dispersive spectroscopy-attenuated total reflectance Fourier transform infrared spectroscopy and static contact angle measurements are used to characterize the as-formed layer. Findings After surface modification, B10 can significantly reduce SRB adhesion, demonstrating the good antifouling property. Further, the biocorrosion inhibition is investigated by potentiodynamic polarization and electrochemical impedance spectroscopy, indicating that ZML exhibits high resistance to biocorrosion with inhibition efficiency of approximately 90 per cent. Originality/value ZML performs a dual feature, i.e. antifouling film and corrosion inhibitor, for the biocorrosion inhibition.

Fatty acids evaluation by Principal Component Analysis for the traceability of Sicilian and Calabrian olive oils

2021 ◽  
Vol 17 ◽  
Author(s):  
Francesco Caridi ◽  
Antonio Francesco Mottese ◽  
Maurizio Messina ◽  
Maurizio D'Agostino
Keyword(s):  
Fatty Acids ◽  
Principal Component Analysis ◽  
Gas Chromatography ◽  
Chemical Composition ◽  
Southern Italy ◽  
Principal Component ◽  
Component Analysis ◽  
Olive Oils ◽  
Product Authenticity ◽  
Comprehensive Study

Background and Objectives: In this article a comprehensive study was carried out for Sicilian and Calabrian olive oils authenticity evaluation through chemometric analyses, correlating botanical and geographical origins with samples chemical composition. Method: A total of eighteen Sicilian and Calabrian (southern Italy) olive oil samples were analyzed through gas chromatography (GC). Results: The fatty acids concentration in the investigated samples followed the subsequent order: oleic (C18:1) > palmitic (C16) > linoleic (C18:2) > stearic (C18) > palmitoleic (C16:1) > linoleic (C18:3). The 2D Scatterplot (Principal Component Analysis) showed that, among the analyzed oils, six clusters stand out, which seem to consistently group samples in relation to the cultivars and cultivation areas that share the territorial proximity (same province). Conclusions: Experimental results demonstrated that it is possible to strictly relate, through the PCA, olive oils to their geographical and botanical provenance, thus becoming a useful tool for evaluating product authenticity and to guarantee it to the consumers.

scholarly journals Detection of Gadolinium with an Impedimetric Platform Based on Gold Electrodes Functionalized by 2-Methylpyridine-Substituted Cyclam

Sensors ◽  
2021 ◽  
Vol 21 (5) ◽  
pp. 1658
Author(s):  
Hassen Touzi ◽  
Yves Chevalier ◽  
Marie Martin ◽  
Hafedh Ben Ouada ◽  
Nicole Jaffrezic-Renault
Keyword(s):  
Thin Films ◽  
Chemical Sensor ◽  
Electrochemical Impedance ◽  
13C Nmr Spectroscopy ◽  
Electrical Circuit ◽  
Gold Electrodes ◽  
Force Microscopy ◽  
Angle Measurements ◽  
Film Electrolyte ◽  
In Series

Gadolinium is extensively used in pharmaceuticals and is very toxic, so its sensitive detection is mandatory. This work presents the elaboration of a gadolinium chemical sensor based on 2-methylpyridine-substituted cyclam thin films, deposited on gold electrodes, using electrochemical impedance spectroscopy (EIS). The 2-methylpyridine-substituted cyclam (bis-N-MPyC) was synthesized in three steps, including the protection of cyclam by the formation of its CH2-bridged aminal derivative; the product was characterized by liquid 1H and 13C NMR spectroscopy. Spin-coated thin films of bis-N-MPyC on gold wafers were characterized by means of infrared spectroscopy in ATR (Attenuated Total Reflectance) mode, contact angle measurements and atomic force microscopy. The impedimetric chemical sensor was studied in the presence of increasing concentrations of lanthanides (Gd3+, Eu3+, Tb3+, Dy3+). Nyquist plots were fitted with an equivalent electrical circuit including two RC circuits in series corresponding to the bis-N-MPyC film and its interface with the electrolyte. The main parameter that varies with gadolinium concentration is the resistance of the film/electrolyte interface (Rp), correlated to the rate of exchange between the proton and the lanthanide ion. Based on this parameter, the detection limit obtained is 35 pM. The bis-N-MPyC modified gold electrode was tested for the detection of gadolinium in spiked diluted negative urine control samples.

scholarly journals Mathematical Model to Predict the Affinity Between Aggregate/Bitumen

2020 ◽  
Vol 22 (3) ◽  
pp. 197
Author(s):  
P. Caputo ◽  
G.A. Ranieri ◽  
D. Miriello ◽  
A. Bloise ◽  
A.A. Abe ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Contact Angle ◽  
Chemical Composition ◽  
Bond Angle ◽  
Angle Measurements ◽  
Significant Difference ◽  
Road Surfaces ◽  
Contact Angle Measurements ◽  
Established Fact ◽  
The Mathematical Model

The stones used for the construction of road surfaces have a complex mineralogical and hence chemical composition. They are made up of several types of minerals put together. This generates a significant difference in adhesion with the bituminous binder. The aim of this study is to create a mathematical model able to predict the adhesion between bitumen and stone on the basis of contact angle measurements made on different pure minerals. The mathematical model used was developed keeping in mind the exponential bond that the minerals have with the corresponding bond angle. This model also confirmed the established fact that the lower the value of Δ, the better the adhesion between the bitumen and the aggregate.

Surface characterization by XPS, contact angle measurements and ToF-SIMS of cellulose fibers partially esterified with fatty acids

2006 ◽  
Vol 301 (1) ◽  
pp. 205-209 ◽  
Author(s):  
Carmen S.R. Freire ◽  
Armando J.D. Silvestre ◽  
Carlos Pascoal Neto ◽  
Alessandro Gandini ◽  
Pedro Fardim ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Contact Angle ◽  
Surface Characterization ◽  
Cellulose Fibers ◽  
Angle Measurements ◽  
Tof Sims ◽  
Contact Angle Measurements

Determination of pK a of benzoic acid- and p-aminobenzoic acid-modified platinum surfaces by electrochemical and contact angle measurements

2012 ◽  
Vol 66 (12) ◽  
Author(s):  
Secil Tekin-Celebi ◽  
Ali Solak ◽  
Zafer Ustundag ◽  
Serkan Demirci
Keyword(s):  
Contact Angle ◽  
Benzoic Acid ◽  
Platinum Electrode ◽  
Electrochemical Impedance ◽  
Ph Dependence ◽  
Bulk Solution ◽  
Acidity Constant ◽  
Aminobenzoic Acid ◽  
Angle Measurements ◽  
Contact Angle Measurements

AbstractAcidity constant values of benzoic acid (BA)-modified platinum electrode (Pt-BA) and p-aminobenzoic acid (pABA)-modified platinum electrode (Pt-NHBA) surfaces were determined using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and contact angle measurements (CAM). Diazonium tetrafluoroborate salt reduction and pABA oxidation reactions were used to prepare (Pt-BA) and (Pt-NHBA) surfaces, respectively. Both surfaces exhibited pH dependence with [Fe(CN)6]3−/4− redox probe solutions at different pH; this allowed us to estimate the surface pK a values. Acidity constants for Pt-BA surface were found to be pK a (3.09 ± 0.25), (4.89 ± 0.11), and (3.91 ± 0.54) by CV, EIS, and CAM techniques, respectively, while the values for Pt-NHBA surface were pK a (3.16 ± 0.45), (4.24 ± 0.40), and (5.64 ± 0.12). The Pt-BA surface pK a values were lower in CV and CAM measurements relative to the bulk solution of BA, while a higher value was observed in EIS for Pt-BA surface. The pK a values determined for Pt-NHBA surface via both CV and EIS were lower than the bulk value; however, the result obtained from CAM was one unit higher than pK a of bulk pABA.

scholarly journals Effect of Maturity and Environmental Conditions on Chemical Composition of Olive Oils of Introduced Cultivars in Morocco

2019 ◽  
Vol 2019 ◽  
pp. 1-14 ◽  
Author(s):  
Samira El Qarnifa ◽  
Abderraouf El Antari ◽  
Abdellatif Hafidi
Keyword(s):  
Fatty Acids ◽  
Fatty Acid Composition ◽  
Fatty Acid ◽  
Chemical Composition ◽  
Olive Oil ◽  
Peroxide Value ◽  
Oil Content ◽  
Total Phenol Content ◽  
Phenol Content ◽  
Olive Oils

This work aims at evidencing the quality and chemical composition of extra virgin olive oils according to stages of maturity and in relation to the geographical location of olives. Three different olive cultivars (Moroccan Picholine, Languedoc Picholine, and Frantoio), grown in two different locations in Morocco (Errachidia and Marrakech), were studied during the two crop years (2016 and 2017) at three stages of maturity (green, purple, and black). This work has been carried out by analyzing several parameters, such as the quality characteristics (acidity and peroxide value), the chemical composition (total phenol content and fatty acid composition) of the oils, and also the fruit characteristics of the olives (maturity index, fruit water content, and oil content). The results obtained in this study indicate that as maturity advanced, there was a slight rise in oil content and acidity, while there was a decrease in fruit water content and peroxide value in both locations during the two crop years. The fatty acid composition of extra virgin olive oil showed a significant increase of linoleic acid and polyunsaturated fatty acids (PUFAs) and a decrease of oleic acid, palmitic acid, monounsaturated fatty acids (MUFAs), and MUFA/PUFA ratio as the maturation process progressed. A significant gradual decrease was noted in total phenol content and bitterness intensity from the green stage to the black. Moreover, olive oil composition differed clearly between the two sites. Therefore, the olive cultivar, harvesting date, and geographic location influence the olive oil characteristics.

Enhancement of corrosion resistance of mild steel in NaCl solution with an eco-friendly silane coating containing nanoclay and zinc acetylacetonate

2018 ◽  
Vol 47 (5) ◽  
pp. 424-430
Author(s):  
M. Taheri ◽  
Reza Naderi ◽  
Mohamad Mahdavian
Keyword(s):  
Mild Steel ◽  
Electrochemical Impedance ◽  
Sol Gel ◽  
Barrier Properties ◽  
Water Contact ◽  
Content Type ◽  
Angle Measurements ◽  
Silane Coating ◽  
Contact Angle Measurements ◽  
Zinc Acetylacetonate

Purpose This paper aims to enhance the barrier properties and active protection of a water-based silane coating on mild steel through nanoclay and zinc acetylacetonate simultaneously included into the formulation. Design/methodology/approach The corrosion protection performance of the silane sol-gel coatings with no additive, zinc acetylacetonate, nanoclay and nanoclay + zinc acetylacetonate was monitored using electrochemical impedance spectroscopy during 5 h of immersion in a sodium chloride solution. Moreover, the surface of coatings was analyzed using a field emission scanning electron microscopy equipped with an energy dispersive X-ray spectrometer (FESEM-EDX) and water contact angle measurements. Findings In electrochemical impedance spectroscopy analysis, the impedance at low frequencies, coating resistance and charge transfer resistance were the parameters considered which indicated the superiority of silane coating formulated with both nanoclay and zinc acetylacetonate. According to the results of FESEM/EDX and water contact angle measurements, the superiority was linked with the enhancement in the barrier properties in the presence of nanoclay, as well as function of the corrosion inhibitor at coating–substrate interface. Originality/value According to the literature, there is no research conducted to study the impact of the simultaneous use of nanoclay and zinc acetylacetonate on the barrier properties and active protection of an eco-friendly silane sol-gel coating including glycidyloxypropyltrimethoxysilane, tetraethoxysilane and methyltriethoxysilane on mild steel in a sodium chloride solution.

scholarly journals Effect of Ammonia Fumigation Treatment on Wood Color and Chemical Composition

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Weigang Zhang ◽  
Minzhen Bao ◽  
Weisheng Sun ◽  
Lei Huang ◽  
Liang Cheng
Keyword(s):  
Chemical Composition ◽  
Color Difference ◽  
Thermomechanical Analysis ◽  
Treatment Temperature ◽  
Degree Of Crystallinity ◽  
Test Material ◽  
Wood Color ◽  
Angle Measurements ◽  
Contact Angle Measurements ◽  
Betula Alnoides

Betula alnoides was used as a test material to study the effect of ammonia fumigation treatment on wood color and chemical composition. The effects of concentration, temperature, and duration of ammonia fumigation on wood color were studied. The properties of the material were studied using contact angle measurements, X-ray diffraction, Fourier-transform infrared spectroscopy, and dynamic thermomechanical analysis. In general, the color difference of the wood increased with the concentration of ammonia used in the fumigation process, treatment temperature, and treatment duration. After ammonia fumigation treatment, the chemical composition of hydroxyl and carboxyl groups in the wood was reduced. We concluded that ammonia fumigation treatment decreased material wettability and dynamic mechanical rigidity and increased the degree of crystallinity in wood.

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