scholarly journals Spectroelectrochemical Determination of Isoprenaline in a Pharmaceutical Sample

Sensors ◽  
2020 ◽  
Vol 20 (18) ◽  
pp. 5179
Author(s):  
Fabiola Olmo ◽  
Jesus Garoz-Ruiz ◽  
Julia Carazo ◽  
Alvaro Colina ◽  
Aranzazu Heras
Keyword(s):  
Optical Fibers ◽  
Reaction Mechanisms ◽  
Sodium Metabisulfite ◽  
Dual Sensor ◽  
Drug Sample ◽  
Pharmaceutical Sample ◽  
Parallel Configuration ◽  
Characterization Of Materials

UV/Vis absorption spectroelectrochemistry (SEC) is a multi-response technique that has been commonly used for the characterization of materials and the study of reaction mechanisms. However, it has been scarcely used for quantitative purposes. SEC allows us to obtain two analytical signals simultaneously, yielding a dual sensor in just one experiment. In the last years, our group has developed new devices useful for analysis. In this work, a SEC device in parallel configuration, based on optical fibers fixed on screen-printed electrodes, was used to determine isoprenaline in a commercial drug, using both, the electrochemical and the spectroscopic signals. In this commercial drug, isoprenaline is accompanied in solution by other compounds. Among them is sodium metabisulfite, an antioxidant that strongly interferes in the isoprenaline determination. A simple pretreatment of the drug sample by bubbling wet-air allows us to avoid the interference of metabisulfite. Here, we demonstrate again the capabilities of UV/Vis absorption SEC as double sensor for analysis and we propose a simple pretreatment to remove interfering compounds.

Extended characterization of materials based on continuous instrumented indentation diagrams

2021 ◽  
Vol 2021 (3) ◽  
pp. 10-23
Author(s):  
B. A. Galanov ◽  
◽  
S. M. Ivanov ◽  
V. V. Kartuzov ◽  
◽  
...  
Keyword(s):  
Material Flow ◽  
Elastic Moduli ◽  
Contact Stiffness ◽  
Relative Size ◽  
Indentation Hardness ◽  
Instrumented Indentation ◽  
Characterization Of Materials ◽  
Instrumental Indentation

In addition to the traditional determination of hardness and elastic moduli from continuous diagrams of instrumental indentation, it is proposed to determine the yield stress, the characteristic of plasticity, the characteristic relative size of the elastoplastic zone under the indenter, and the volumetric deformation of the material in the area of contact of the indenter with the sample. The indentation diagram shows the transition point to the unconstrained material flow under the indenter. Keywords: indentation, hardness, elastic moduli, contact stiffness, elastic-plastic strains.

Characterization of Superplastic Materials by Results of Free Bulging Tests

2016 ◽  
Vol 838-839 ◽  
pp. 552-556 ◽  
Author(s):  
Sergey A. Aksenov ◽  
Ivan Y. Zakhariev ◽  
Aleksey V. Kolesnikov ◽  
Sergey A. Osipov
Keyword(s):  
Simple Technique ◽  
Main Idea ◽  
Main Subject ◽  
Material Constants ◽  
Element Simulation ◽  
Simplified Solution ◽  
Characterization Of Materials ◽  
Free Bulging

Determination of material constants describing its behavior during superplastic gas forming is the main subject of this study. The main feature of free bulging tests is the stress-strain conditions which are very similar to ones occurring in the most of gas forming processes. On the other hand, the interpretation of the results of such tests is a complicated procedure. The paper presents a simple technique for the characterization of materials superplasticity by free bulging tests, which is based on inverse analysis. The main idea of this technique is a semianalytical solution of the direct problem instead of finite element simulation which allows one to reduce the calculation time significantly. At the same time the results this simplified solution are accurate enough to obtain realistic material constants.

Comparative Experimental Analysis of Different Bending Methods for the Mechanical Characterization of Materials with Previous Loading History (Stress-Strain Curves)

2011 ◽  
Vol 314-316 ◽  
pp. 1377-1382
Author(s):  
David Torres Franco ◽  
Guillermo Urriolagoitia-Sosa ◽  
Guillermo Urriolagoitia-Calderón ◽  
Luis Hector Hernandez Gomez ◽  
Beatriz Romero Angeles ◽  
...  
Keyword(s):  
Simultaneous Determination ◽  
Compression Stress ◽  
Loading History ◽  
Stress Strain ◽  
Axial Tensile ◽  
Tension And Compression ◽  
Characterization Of Materials ◽  
Previous Loading

Until now, the most common way to obtain the stress-strain curves for a material is through axial tensile testing. However, in recent years there have been developments on alternative methods for material characterization. In this sense, the bending procedure has proved to be a powerful technique, which allows simultaneous determination of tension and compression stress behavior by the use of bending moment and strain data. The characterization of materials by means of bending data was presented for the first time in 1910 by the German engineer Herbert. Some years later Nadai and Marin developed some research on this procedure. More recently, several researchers (Mayville and Finnie, Laws and Urriolagoitia-Sosa, et.al.) have developed diverse bending methods for the simultaneous determination of tension and compression stress-strain curves. In this paper, three bending methods are analyzed and compared against axial tensile and compressive results. It was decided to apply each one of the bending procedures to bent rectangular cross sections beams made from 6063-T5 Aluminum alloy. The specimens were annealed to eliminate previous loading history and axially pulled to induce a controlled anisotropic behavior (strain hardening and Bauschinger effect). The results obtained by two of the three methods provided great confidence and have certified the application of this new technique to characterize material.

scholarly journals Exploitation of Nanoindentation and Statistical Tools to Investigate the Behavior of Materials

2016 ◽  
Vol 6 (4) ◽  
pp. 1089-1092
Author(s):  
L. Aminallah ◽  
S. Habibi
Keyword(s):  
Polynomial Regression ◽  
Contact Stiffness ◽  
Characteristic Curve ◽  
Indentation Test ◽  
Statistical Processing ◽  
Indentation Load ◽  
Contact Depth ◽  
Characterization Of Materials

The determination of the performance of materials requires the characterization of materials at scales: macro, micro and nanoscale. Among the most common experimental methods one can find the instrumented indentation test for determining the contact stiffness and contact depth and analyzing the characteristic curve by nanoindentation load on the penetration of the indentor. Through statistical processing of the experimental results, the rigidity of contact on the contact depth is investigated, depending on the indentation load, for bronze, brass and copper. A mathematical model is adopted to describe the polynomial regression by the method of least squares growth rigidity with one or more geometric parameters representative of the size of the footprint. This study allows us to identify factors that influence the rigidity of the materials examined and the sensitivity of the used indenters.

scholarly journals Evaluation of the GPR (1.2 GHz) technique in the characterization of masonry shells of the Theatro Municipal do Rio de Janeiro

2020 ◽  
Vol 13 (2) ◽  
pp. 274-297
Author(s):  
D. C. B. CINTRA ◽  
P. M. B. MANHÃES ◽  
F. M. C. P. FERNANDES ◽  
D. M. ROEHL ◽  
J. T. ARARUNA JÚNIOR ◽  
...  
Keyword(s):  
Rio De Janeiro ◽  
Structural Integrity ◽  
Cultural Value ◽  
Sample Extraction ◽  
Characterization Of Materials ◽  
Main Component ◽  
Ground Penetrating ◽  
Non Destructive

Abstract The geometric characterization and evaluation of structural integrity are challenges for the preservation of historical buildings. The challenges are associated to the lack of constructive records, material diversity, access and contact restrictions, and sample extraction. Non-destructive tests are indicated in these cases. The objective of this paper is to evaluate the Ground Penetrating Radar (GPR) technique with 1.2 GHz antenna in the study of the determination of material thickness and discontinuities in the masonry shells of the Theatro Municipal do Rio de Janeiro, a heritage built in early 20th century, with high historical and cultural value. With paintings by renowned artists on their intrados, the domes and vault of brick masonry were at risk of collapse in the 1970s due to differential settlements in the supports and moisture, compromising their paintings. A strengthening intervention was carried out in 1976. Considering the masonry of bricks the main component, the electromagnetic wave propagation velocity was determined as 0,15 m/ns in one of the support walls, allowing to estimate the thicknesses of the elements ranging between 20 and 31 cm. Materials incorporated into the structure were identified: reinforcement, metal inserts and bricks. However, the frequency of the antenna did not allow the detection of damages. The application of the GPR to the characterization of materials and investigation of the integrity of the domes of the Theatro Municipal highlights the potential of this technology to study heritage and other constructions.

Application of Sans to Ceramic Characterization

1986 ◽  
Vol 73 ◽  
Author(s):  
K. G. Frase ◽  
K. A. Hardman-Rhyne ◽  
N. F. Berk
Keyword(s):  
Neutron Scattering ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Ceramic Materials ◽  
Pore Size Distributions ◽  
Mdf Cements ◽  
Characterization Of Materials ◽  
Non Destructive

ABSTRACTTraditionally, small angle neutron scattering (SANS) has been used to study dilute concentrations of defects 1 -100 nm in size. Recent extensions of the scattering theory have allowed the expansion of the technique to include larger sizes through the use of multiple scattering. With multiple small angle neutron scattering, defects (pores, microcracks, precipitates) up to 10 μm in size can be studied. SANS is inherently a non-destructive, bulk probe of microstructure, with wide applications in the characterization of materials.A number of studies of ceramic materials using multiple and traditional (single particle diffraction) small angle neutron scattering will be discussed. The emphasis will be on the strength of the technique in the characterization of materials. Particular examples will include: the assessment of pore size distributions in spinel compacts as a function of sintering and agglomeration, the characterization of primary and secondary particle sizes in precipitated aggregates, and the determination of microporosity in MDF cements.

Remote characterization of Materials by vibrational spectrometry through optical fibers

1995 ◽  
Vol 347 ◽  
pp. 169-185 ◽  
Author(s):  
Peter R Griffiths ◽  
Ian R Lewis ◽  
Nathan C Chaffin ◽  
Nelson W Daniel ◽  
John D Jegla
Keyword(s):  
Optical Fibers ◽  
Characterization Of Materials

Some applications of electron beam microanalysis techniques in VLSI process evaluation

1983 ◽  
Vol 41 ◽  
pp. 160-161
Author(s):  
Simon Thomas
Keyword(s):  
Integrated Circuits ◽  
Process Evaluation ◽  
Large Scale ◽  
Technology Development ◽  
Analytical Techniques ◽  
Successful Implementation ◽  
Analysis Of Failures ◽  
Characterization Of Materials ◽  
Circuits Vlsi

Trends in the technology development of very large scale integrated circuits (VLSI) have been in the direction of higher density of components with smaller dimensions. The scaling down of device dimensions has been not only laterally but also in depth. Such efforts in miniaturization bring with them new developments in materials and processing. Successful implementation of these efforts is, to a large extent, dependent on the proper understanding of the material properties, process technologies and reliability issues, through adequate analytical studies. The analytical instrumentation technology has, fortunately, kept pace with the basic requirements of devices with lateral dimensions in the micron/ submicron range and depths of the order of nonometers. Often, newer analytical techniques have emerged or the more conventional techniques have been adapted to meet the more stringent requirements. As such, a variety of analytical techniques are available today to aid an analyst in the efforts of VLSI process evaluation. Generally such analytical efforts are divided into the characterization of materials, evaluation of processing steps and the analysis of failures.

Applications of ultramicrotomy for materials characterization

1993 ◽  
Vol 51 ◽  
pp. 232-233
Author(s):  
R.T. Blackham ◽  
J.J. Haugh ◽  
C.W. Hughes ◽  
M.G. Burke
Keyword(s):  
Materials Science ◽  
Microstructural Analysis ◽  
Analytical Electron Microscopy ◽  
Austenitic Stainless Steels ◽  
Specimen Preparation ◽  
Preparation Technique ◽  
Thermally Induced ◽  
Radiation Induced ◽  
Characterization Of Materials

Essential to the characterization of materials using analytical electron microscopy (AEM) techniques is the specimen itself. Without suitable samples, detailed microstructural analysis is not possible. Ultramicrotomy, or diamond knife sectioning, is a well-known mechanical specimen preparation technique which has been gaining attention in the materials science area. Malis and co-workers and Glanvill have demonstrated the usefulness and applicability of this technique to the study of a wide variety of materials including Al alloys, composites, and semiconductors. Ultramicrotomed specimens have uniform thickness with relatively large electron-transparent areas which are suitable for AEM anaysis.Interface Analysis in Type 316 Austenitic Stainless Steel: STEM-EDS microanalysis of grain boundaries in austenitic stainless steels provides important information concerning the development of Cr-depleted zones which accompany M23C6 precipitation, and documentation of radiation induced segregation (RIS). Conventional methods of TEM sample preparation are suitable for the evaluation of thermally induced segregation, but neutron irradiated samples present a variety of problems in both the preparation and in the AEM analysis, in addition to the handling hazard.

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