Emission Spectrographic Analysis of Surfaces with an Ion-Sputtering Source

1976 ◽  
Vol 30 (5) ◽  
pp. 510-515 ◽  
Author(s):  
M. E. Waitlevertch ◽  
J. K. Hurwitz
Keyword(s):  
Power Supply ◽  
Sample Surface ◽  
Argon Atmosphere ◽  
Concentration Profiles ◽  
Spectrographic Analysis ◽  
Ion Sputtering ◽  
Square Wave ◽  
Source Current ◽  
Depth Concentration

An ion-sputtering source was installed and evaluated as an emission spectrographic source for the analysis of metal surfaces and for the determination of in-depth concentration profiles. This source generates a direct current glow discharge in a low-pressure argon atmosphere between a hollow stainless-steel anode and the sample (the cathode) and sputters material at a controlled rate from the sample surface. The resultant spectrum of the sputtered material is recorded photographically, and the analysis is completed by conventional spectrographic techniques. The power supply of the source can be operated in either a constant dc mode or a square-wave dc mode, but better repeatability and accuracy have been achieved with the square-wave dc mode. Before any significant sputtering occurs with this source, the voltage must exceed 240 Volts, the threshold sputtering voltage. The sputtering rate increases with both source current and voltage. This source has been used for the quantitative analysis of the surface of steel products and the determination of changes in composition with depth below the surface.

Simultaneous Square-Wave Voltammetric Determination of Paracetamol, Caffeine and Orphenadrine in Pharmaceutical Formulations Using a Cathodically Pretreated Boron-Doped Diamond Electrode

2013 ◽  
Vol 25 (7) ◽  
pp. 1734-1741 ◽  
Author(s):  
Ana Paula Pires Eisele ◽  
Débora Nóbile Clausen ◽  
César Ricardo Teixeira Tarley ◽  
Luiz Henrique Dall'Antonia ◽  
Elen Romão Sartori
Keyword(s):  
Pharmaceutical Formulations ◽  
Voltammetric Determination ◽  
Boron Doped Diamond ◽  
Square Wave ◽  
Diamond Electrode ◽  
Boron Doped ◽  
Boron Doped Diamond Electrode

scholarly journals Migration of mineral oil in elastomers

2021 ◽  
Author(s):  
Tobias Förster ◽  
Artur Blivernitz
Keyword(s):  
Diffusion Coefficients ◽  
Mineral Oil ◽  
Activation Energies ◽  
Concentration Profiles ◽  
Small Reservoir ◽  
Experimental Procedure ◽  
Mineral Oils ◽  
The Absolute ◽  
Suitable Measure

AbstractThis work describes a newly introduced experimental procedure to quantify the diffusion progress of mineral oils locally resolved in NBR. Diffusion of reference oils IRM 901, IRM 902 and IRM 903 in NBR with various acrylonitrile contents was investigated. Classical sorption experiments were performed as a basic characterization and compared to the newly introduced method. Here, elastomer specimens are only being dipped with the bottom in a relatively small reservoir of mineral oil. This provides a determination of locally resolved concentration profiles of mineral oils, and the calculation of diffusion coefficients. These diffusion coefficients follow the same trends like those determined via sorption experiments. Despite differences in the absolute numbers, activation energies of diffusion can be applied as a suitable measure for the compatibility of elastomers and fluids.

scholarly journals Method of Estimating Uncertainty as a Way to Evaluate Continuity Quality of Power Supply in Hospital Devices

Energies ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 486
Author(s):  
Marek Stawowy ◽  
Adam Rosiński ◽  
Jacek Paś ◽  
Tomasz Klimczak
Keyword(s):  
Power Systems ◽  
Power Supply ◽  
Uncertainty Modeling ◽  
Supply System ◽  
Additional Advantage ◽  
Quality Models ◽  
Reliability Indicators ◽  
Electrical Devices

The article presents issues related to the determination of the continuity quality of power supply (CQoPS) for hospital electrical devices. The model describing CQoPS takes into account power redundancy. The uncertainty modeling method based on the certainty factor (CF) of the hypothesis was used to establish the single-valued CQoPS factor. CQoPS modeling takes into account multidimensional quality models and physical stages of power. The quality models take into account seven dimensions that make up CQoPS (availability, appropriate amount, power supply reliability, power quality, assurance, responsiveness, security). The model of power stages includes five of these stages (power generation, delivery to recipient, distribution by recipient, delivery to device, power-consuming device). To date, when designing hospital power systems, the applied reliability indicators revealed limitations because they do not consider all the possible factors influencing the power continuity. Estimating the supply continuity quality with the use of the uncertainty modeling proposed in this article allows for taking into account all possible factors (not just reliability factors) that may affect supply continuity. The presented modeling offers an additional advantage, namely, it allows an expanded evaluation of the hospital supply system and a description using only one indicator. This fact renders the evaluation of the supply system possible for unqualified staff. At the end of the article, some examples of calculations and simulations are presented, thus showing that the applied methods give the expected results.

scholarly journals A Magnetic Nanocomposite Modifier for Improved Ultrasensitive Detection of Hexavalent Chromium in Water Samples

Chemosensors ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 189
Author(s):  
Nuša Hojnik ◽  
Olivija Plohl ◽  
Matjaž Finšgar
Keyword(s):  
Electron Microscopy ◽  
Analytical Performance ◽  
Magnetic Nanocomposite ◽  
Ex Situ ◽  
Trace Determination ◽  
Silica Layer ◽  
X Ray ◽  
Square Wave ◽  
Static Contact

In this work, different electrodes were employed for the determination of Cr(VI) by the cathodic square‑wave voltammetry (SWV) technique and the square-wave adsorptive stripping voltammetry (SWAdSV) technique in combination with diethylenetriaminepentaacetic acid. Using SWV, a comparison of the analytical performance of the bare glassy carbon electrode (GCE), ex situ electrodes (antimony-film—SbFE, copper-film—CuFE, and bismuth-film—BiFE), and the GCE modified with a new magnetic nanocomposite (MNC) material was performed. First, the MNC material was synthesized, i.e., MNPs@SiO2@Lys, where MNPs stands for magnetic maghemite nanoparticles, coated with a thin amorphous silica (SiO2) layer, which was additionally functionalized with derived lysine (Lys). The crystal structure of the prepared MNCs was confirmed by X-ray powder diffraction (XRD), while the morphology and nano-size of the MNCs were investigated by field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM), where TEM was additionally used to observe the MNP core and silica layer thickness. The presence of functional groups of the MNCs was investigated by attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) and surface analysis was performed by X-ray photoelectron spectroscopy (XPS). The hydrophilicity of the modified electrodes was also tested by static contact angle measurements. Then, MNPs@SiO2@Lys was applied onto the electrodes and used with the SWV and SWAdSV techniques. All electrodes tested with the SWV technique were effective for Cr(VI) trace determination. On the other hand, the SWAdSV technique was required for ultra-trace determination of Cr(VI). Using the SWAdSV technique, it was shown that a combination of ex situ BiFE with the deposited MNPs@SiO2@Lys resulted in excellent analytical performance (LOQ = 0.1 µg/L, a linear concentration range of 0.2–2.0 µg/L, significantly higher sensitivity compared to the SWV technique, an RSD representing reproducibility of 9.0%, and an average recovery of 98.5%). The applicability of the latter system was also demonstrated for the analysis of a real sample.

scholarly journals Square-wave voltammetric determination of rutin in pharmaceutical formulations using a carbon composite electrode modified with copper (II) phosphate immobilized in polyester resin

2012 ◽  
Vol 48 (4) ◽  
pp. 639-649 ◽  
Author(s):  
Kellen Heloizy Garcia Freitas ◽  
Orlando Fatibello-Filho ◽  
Ivanildo Luiz de Mattos
Keyword(s):  
Modified Electrode ◽  
Composite Electrode ◽  
Polyester Resin ◽  
Pharmaceutical Formulations ◽  
Carbon Composite ◽  
X Ray ◽  
Square Wave ◽  
Wave Voltammetry ◽  
Carbon Composite Electrode

A carbon composite electrode modified with copper (II) phosphate immobilized in a polyester resin (Cu3(PO4)2-Poly) for the determination of rutin in pharmaceutical samples by square-wave voltammetry is described herein. The modified electrode allows the determination of rutin at a potential (0.20 V vs. Ag/AgCl (3.0 mol L-1 KCl)) lower than that observed at an unmodified electrode. The peak current was found to be linear to the rutin concentration in the range from 9.9 × 10-8 to 2.5 × 10-6 mol L-1, with a detection limit of 1.2×10-8 mol L-1. The response of the electrode was stable, with no variation in baseline levels within several hours of continuous operation. The surface morphology of the modified electrode was characterized by scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) system. The results obtained are precise and accurate. In addition, these results are in agreement with those obtained by the chromatographic method at a 95% confidence level.

scholarly journals Square wave polarographic determination of sulphur ions

1970 ◽  
Vol 19 (7) ◽  
pp. 902-907 ◽  
Author(s):  
Hitoo KAKIYAMA ◽  
Masahiro KOMATSU
Keyword(s):  
Polarographic Determination ◽  
Square Wave
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