A Scan Rate Dependent Determination of Platinum Areas

1982 ◽  
Vol 129 (4) ◽  
pp. 746-749 ◽  
Author(s):  
G. G. Barna ◽  
S. N. Frank ◽  
T. H. Teherani
Keyword(s):  
Rate Dependent ◽  
Scan Rate

Determination of Strain Rate Depended Stress and Strain Fields in PVD Coatings on Cemented Carbide Inserts during the Repetitive Impact Test

2020 ◽  
Vol 404 ◽  
pp. 45-52
Author(s):  
Antonios Bouzakis ◽  
Georgios Skordaris ◽  
Konstantinos Dionysios Bouzakis ◽  
Mehmet Gökhan Gökcen ◽  
Apostolos Boumpakis ◽  
...  
Keyword(s):  
Strain Rate ◽  
Cemented Carbide ◽  
Stress And Strain ◽  
Strain Fields ◽  
Rate Dependent ◽  
Impact Forces ◽  
Repetitive Impact ◽  
Carbide Inserts ◽  
Fatigue Endurance

Recently, stress, strain, strain-rate dependent curves for cemented carbide have become an established tool for evaluating the mechanical properties. In this paper, related strain-rate dependent data of a K05 insert were employed to define the developed stress and strain fields occurring in the compound coating-substrate at impact forces of various durations. In this way, the occurring maximum strains at various impact loads and times were analytically calculated. These maximum values and related fatigue endurance coating strain-rate dependent limits were consequently used to validate published coating fatigue critical impact forces associated with certain impact times.

Corrosion of Al CoCrFeNi high-entropy alloys: Al-content and potential scan-rate dependent pitting behavior

2017 ◽  
Vol 119 ◽  
pp. 33-45 ◽  
Author(s):  
Yunzhu Shi ◽  
Bin Yang ◽  
Xie Xie ◽  
Jamieson Brechtl ◽  
Karin A. Dahmen ◽  
...  
Keyword(s):  
High Entropy Alloys ◽  
High Entropy ◽  
Al Content ◽  
Rate Dependent ◽  
Scan Rate

Velocity of Torsional Waves in Metals Stressed Statically into the Plastic Range

1968 ◽  
Vol 10 (2) ◽  
pp. 153-164 ◽  
Author(s):  
E. Convery ◽  
H. LI. D. Pugh
Keyword(s):  
Strain Rate ◽  
Strain Curve ◽  
Plastic Range ◽  
Stress Strain Curve ◽  
Rate Dependent ◽  
Torsional Waves ◽  
Dependent Theory ◽  
Velocity Of Propagation ◽  
Elastic Shear

This paper is concerned with the determination of the velocity of propagation of torsional plastic waves in metals stressed statically into the plastic range. A new method was developed in which a tubular test specimen together with a concentric bar of a brittle material was twisted slowly such that when the specimen was stressed beyond its yield the brittle bar broke suddenly and transmitted a plastic torsional stress increment along the specimen. It was found that the velocity of propagation both in copper and mild steel was the same as the elastic shear wave velocity. Although consistent with the strain-rate dependent theory, the result can be explained in terms of the strain-rate independent theory provided the stress-strain curve for the appropiate strain rate is used.

scholarly journals Determination of Zalcitabine in Medicaments by Differential Pulse Voltammetry

2013 ◽  
Vol 2013 ◽  
pp. 1-6
Author(s):  
Katia Christina Leandro ◽  
Josino Costa Moreira ◽  
Pércio Augusto Mardini Farias
Keyword(s):  
Pulse Amplitude ◽  
Differential Pulse ◽  
Active Principle ◽  
Reduction Peak ◽  
Hanging Mercury Drop Electrode ◽  
Analytical Methodology ◽  
Scan Rate ◽  
Pulse Voltammetry ◽  
Antiretroviral Activity

The zalcitabine (ddC) has been extensively used in the treatment of HIV patients due to its antiretroviral activity. The quality control of this active principle in medications is of outstanding importance to public health. The principal objective of the current study was the development of an alternative analytical methodology for the zalcitabine determination using a voltammetric process. The zalcitabine gives a reduction peak (at -1.22 V versus Ag/AgCl) at the hanging mercury drop electrode (HMDE). The differential pulse voltammetric response is evaluated with respect to the scan rate (20 mV/s), pulse amplitude (50 mV), support electrolyte (Clark-Lubs buffer), pH (2.0), and other variables. The response is linear over the 10.0 to 28.0 mg/L (47 to 133 μM) concentration range, and the detection limit is 2.08 mg/L. The validation of this method was realized using a governmental Brazilian document (Inmetro, 2007) and the results are reported for medication drugs.

Sensitive Determination of Rutin Using a Nafion/PMB/Graphene Composite-Modified Glassy Electrode

2013 ◽  
Vol 641-642 ◽  
pp. 566-569
Author(s):  
Feng Cai ◽  
Jian Fei Xia ◽  
Zong Hua Wang ◽  
Yan Zhi Xia ◽  
Fei Fei Zhang ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Detection Limit ◽  
Modified Electrode ◽  
Linear Relation ◽  
Peak Current ◽  
Good Linear ◽  
Graphene Composite ◽  
Scan Rate ◽  
Sensitive Determination

A novel Nafion/PMB/G/GCE was prepared by firstly electro-polymerization of MB to G/GCE and then coating Nafion on PMB/G/GCE. The as-prepared modified electrode combining the advantages of Nafion, methylene blue and G was employed for the sensitive detection of rutin. The results showed that the peak current of rutin obtained on Nafion/PMB/G/GCE was obviously high compared to bare electrode and G/GCE. Under the optimized value of pH, which was pH 3.0, peak current of rutin had good linear relation with the scan rate. At the same time, peak current increased linearly with increasing concentration of rutin. The linear range was from 5×10-7 mol/L to 1.2×10-5 mol/L, and the detection limit was 9.5×10-8 mol/L

scholarly journals Electrochemical Determination of Metronidazole in Tablet Samples Using Carbon Paste Electrode

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Yosef Nikodimos ◽  
Meareg Amare
Keyword(s):  
Correlation Coefficient ◽  
Carbon Paste Electrode ◽  
Reduction Peak ◽  
Carbon Paste ◽  
Peak Potential ◽  
Peak Current ◽  
Potential Shift ◽  
Scan Rate ◽  
Paste Electrode

Cyclic voltammetric investigation of metronidazole at carbon paste electrode revealed an irreversible reduction peak centered at about −0.4 V. Observed peak potential shift with pH in the range 2.0 to 8.5 indicated the involvement of protons during the reduction of metronidazole, whereas the peak potential shift with scan rate in the range 10–250 mV/s confirmed the irreversibility of the reduction reaction. A better correlation coefficient for the dependence of peak current on the scan rate than on the square root of scan rate indicated an adsorption controlled kinetics. Under the optimized method and solution parameters, an excellent linearity between the reductive peak current and the concentration of metronidazole was observed in the concentration range 1.0 × 10−6to 5.0 × 10−4 M with a correlation coefficient, method detection limit (based ons=3σ), and limit of quantification of 0.999, 2.97 × 10−7 M and 9.91 × 10−7 M, respectively. Good recovery results for spiked metronidazole in tablet samples and selective determination of metronidazole in tablet formulations in the presence of selected potential interferents such as rabeprazole, omeprazole, and tinidazole confirmed the potential applicability of the developed method for the determination of metronidazole in real samples like pharmaceutical tablets.

scholarly journals Penentuan Logam Cr(VI) Menggunakan Metoda Differensial Pulse Adsorptive Stripping Voltammetry dengan Calconcarboxylic Acid Sebagai Pengomplek

2019 ◽  
Vol 11 (2) ◽  
pp. 49-56
Author(s):  
Hilfi Pardi ◽  
Nancy Willian
Keyword(s):  
Stripping Voltammetry ◽  
Differential Pulse ◽  
Adsorptive Stripping Voltammetry ◽  
Scan Rate

[Determination of Cr(VI) Metal Using Differential Pulse Adsorptive Stripping Voltametry Method with Calconcarboxylic Acid as Complexing] Penelitian ini menggunakan metode differential pulse adsorptive stripping voltammetry (DPAdSV) dengan elektroda merkuri tetesan gantung (HMDE) untuk menentukan logam Cr(VI) dengan Calconcarboxylic Acid (CCA) sebagai ligand dalam sampel air laut. Metode ini terjadi berdasarkan deposisi Logam-CCA pada elektroda merkuri pada periode waktu tertentu. Dengan menggunakan scan potensial kearah negatif dan voltammogram differential pulse akan menghasilkan voltammogram yang berbeda. Parameter instrumental dan kimia yang dapat meningkatan pegukuran diperoleh kondisi optimalnya antara lain, konsentrasi CCA 0,5 mM, pH 6, potensial deposisi (Edep) -0,3 V, waktu deposisi (tdep) 60 detik, konsentrasi buffer asetat 0,4 M, scan rate 150 mV/s, tinggi pulse 90 mV, ukuran tetesan merkuri 4 mm2, Linieriti logam Cr (Ip vs konsentrasi) pada kisaran 5 sampai 200 µg/L. Batas deteksi Cr(VI) adalah 0,23 µg/L, standar deviasi relatif 0,24%, recovery 98%. Metode DPAdSV dengan CCA ligands untuk penentuan logam Cr(VI) sukses diaplikasikan pada sampel alam yaitu air laut dan air sungai.

scholarly journals Enhancement of stripping technique for Copper(II) detection in water sample using N,N’-bis(2-hydroxy-4-methoxyacetophenone)ethylenediamine (BME)

2014 ◽  
Vol 10 (3) ◽  
Author(s):  
Syaza Azhari ◽  
Rahmalan Ahamad ◽  
Farediah Ahmad
Keyword(s):  
Tap Water ◽  
Optimal Conditions ◽  
Adsorbed Species ◽  
Accumulation Time ◽  
Highly Sensitive ◽  
Experimental Parameters ◽  
Scan Rate ◽  
Interfering Ions ◽  
Determination Of Copper

A highly sensitive, rapid, simple and selective stripping assay for the determination of trace copper(II) is proposed.  The selectivity and sensitivity of the electroanalytical process on a glassy carbon (GC) electrode were enhanced using the newly synthesized Schiff base N,N’-bis(2-hydroxy-4-methoxyacetophenone)ethylenediamine (BME). The methodology is based on the accumulation of copper(II)–BME complex onto the GC electrode, followed by electrochemical oxidation of the adsorbed species. The effect of experimental parameters such as pH, BME concentration, scan rate, accumulation time and accumulation potential on the sensitivity of copper(II) detection were investigated. Under the optimal conditions, BME has successfully enhanced the copper(II) detection using the GC electrode by nearly 95% with detection limit (LOD) of  2.6 ngL−1. The effects of interfering ions such as Cd(II), Zn(II), Fe(II), Cr(III) and Pb(II) were also investigated. The applicability of this technique was illustrated by the determination of copper(II) ion in tap water.________________________________________GRAPHICAL ABSTRACT 

scholarly journals VOLTAMMETRIC DETERMINATION OF ETHYL NITRITE

2019 ◽  
Vol 62 (12) ◽  
pp. 9-12
Author(s):  
Valentina A. Popova ◽  
Anna A. Krivosheina ◽  
Elena I. Korotkova
Keyword(s):  
Graphite Electrode ◽  
Background Electrolyte ◽  
High Sensitivity ◽  
Physicochemical Characteristics ◽  
Voltammetric Determination ◽  
Nonlinear Dependence ◽  
Buffer Solution ◽  
Scan Rate ◽  
Ethyl Nitrite

The possibility of voltammetric determination of ethyl nitrite on a graphite electrode modified with carbon ink was investigated and described in this study. The physicochemical characteristics of the oxidation process of the compound were studied. A nonlinear dependence of the oxidation current of С2Н5ONO on the scan rate was obtained. This indicates the absence of adsorption on the surface of the electrode. The dependence of the peak current on v 1/2 and the dependence of the potential of the ethylnitrite oxidation peak on log(v 1/2) are linear, indicating that the process is irreversible. The electrochemical behavior of ethyl nitrite on a graphite electrode modified with carbon ink, using voltammetry, has been studied. The effect of various factors on the anode signal of alkylnirite was shown: pH, time and potential of accumulation, potential scan rate. Oxidation of C2H5ONO strongly depends on the pH of the background electrolyte and when the pH is shifted to a neutral and alkaline medium, the current decreases as the number of protons is not sufficient to oxidize nitrite. The maximum current for the electro-oxidation of ethyl nitrite was obtained in an acidic environment. A universal Britton-Robinson buffer solution with pH 4.02 was used as a background electrolyte. The working conditions for the determination of ethyl nitrite in model media were selected: pH 4.02; Eacc 0.4 V; tacc 4.0 s; v = 100 mV∙s-1. The linear regression equation of ethyl nitrite was obtained at a potential of 1 V, in the range of concentrations of 1-10∙10-6 mol∙l-1. The detection limit was 3.8·10-7 mol∙l-1. Thus, a simple and rapid method for the determination of ethyl nitrite with high sensitivity has been developed.

Sign in / Sign up

Export Citation Format

Share Document