Qualitative and Quantitative Evaluation of Different Types of Orthodontic Brackets and Archwires by Optical Microscopy and X-ray Fluorescence Spectroscopy

Prosthesis ◽  
2021 ◽  
Vol 3 (4) ◽  
pp. 342-360
Author(s):  
Danilo D’Andrea ◽  
Dario Milone ◽  
Fabiana Nicita ◽  
Giacomo Risitano ◽  
Dario Santonocito
Keyword(s):  
Optical Microscopy ◽  
Chemical Elements ◽  
Wear Behaviour ◽  
Surface Wear ◽  
Tribological Test ◽  
X Ray ◽  
Qualitative And Quantitative ◽  
Different Types ◽  
Dry Conditions ◽  
Wear Tests

The wear behaviour and chemical composition of orthodontic components influence the mechanical characteristics of a fixed orthodontic treatment. The purpose of this paper is to evaluate the surface alterations of different types of brackets (aesthetic, metallic, and conventional self-ligating) and archwires (superelastic and thermal) subjected to wear tests through optical microscopy and, subsequently, to identify the chemical elements of accessories by X-ray fluorescence. The cycles (5000 for each bracket and 10,000 for each wire) of the tribological test were carried out in dry conditions inside a machine that allows alternating sliding. The results of the study highlighted different wear behaviours even within the same type of brackets and archwires. The monocrystalline sapphire brackets maintain their aesthetic properties despite traces of wear inside the slots and contain minimal amounts of nickel. Superelastic NiTi archwires have a better overall rating than thermal wires, as they do not show significant surface wear alterations.

scholarly journals Evaluation of Wear Behaviour in Metallic Binders Employed in Diamond Tools for Cutting Stone

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3988
Author(s):  
Fátima Ternero ◽  
Pedro M. Amaral ◽  
Jorge Cruz Fernandes ◽  
Luís Guerra Rosa
Keyword(s):  
Wear Behavior ◽  
Wear Behaviour ◽  
Empirical Expression ◽  
Testing Conditions ◽  
Diamond Tools ◽  
Test Methodology ◽  
Different Types ◽  
Stone Material ◽  
The Difference ◽  
Wear Tests

A type of disc-on-plate test methodology was used to determine the wear behavior of metallic binders employed in the manufacturing of diamond impregnated tools. The disc consists of a special circular wheel that allows the binder materials alone (i.e., without diamond, but sintered under conditions identical to those of the complete tool) to be tested against a plate of stone material under pre-determined testing conditions. The testing conditions are intended to be equivalent to those used in the industrial processes. Using plates of five types of granite and one type of marble, this work comprises wear tests of 15 different types of metallic binders and two sintering modes conducted under, at least, three different values of contact-force. The analysis of the results demonstrated that the wear of the binders can be related to their mechanical properties through an empirical expression. The larger the difference between the characteristics of the tribological pair (binder versus stone), the higher is the correlation between the experimental wear data and the values given by the empirical expression. The relationships presented in this work allow predicting the wear behavior of the binder, and therefore may help in the design process of diamond tools. There was a clear difference between the wear behavior of metallic binders when they were employed against the two main classes of stone under analysis (marble and granite).

Comparative Wear Tests of Different Types of Coatings on Steels

1988 ◽  
Vol 140 ◽  
Author(s):  
Karl-Heinz Habig
Keyword(s):  
Abrasive Wear ◽  
High Resistance ◽  
Thermochemical Treatment ◽  
Electroless Nickel ◽  
Wear Behaviour ◽  
Diamond Coatings ◽  
Carbide Coatings ◽  
Different Types ◽  
Plasma Sprayed ◽  
Wear Tests

AbstractDifferent coatings were formed by galvanical deposition, thermochemical treatment, CVD, PVD or plasma spraying. Their wear behaviour was tested under various conditions so that adhesive and abrasive wear mechanisms predominated. The resistance of the coatings to adhesive failure and wear was examined with the pin and disc system under conditions of boundary lubrication. The discs were protected by different coatings while the pins were made of tool steel or alumina. For abrasive wear tests a grinding apparatus with grinding papers of flint, alumina or silicon carbide was used. From the resultsthe following conclusions can be drawn: -Thermochemically treated steels and nickel-phosphorus coatings have a high resistance to galling if the counterbody consists of steel or alumina. The couples plasma sprayed molybdenum against steel and tungsten carbide against alumina also have a high resistance against galling.-The wear of most coatings is low if the counterbody is made of steel. By analumina counterbody the wear of the coatings isincreased. Alumina is worn less by the coatings than steel.-The hard CVD- and PVD-coatings, the thermochemically formed iron boride andvanadium carbide coatings and the electroless nickel-phosphorus-diamond coatings have a high abrasive wear resistance.

X-ray photoelectron spectroscopy characterization of aerosol particles in Antarctica

2015 ◽  
Vol 27 (5) ◽  
pp. 493-499 ◽  
Author(s):  
Simona Rella ◽  
Cosimino Malitesta
Keyword(s):  
Photoelectron Spectroscopy ◽  
Surface Characterization ◽  
Chemical Elements ◽  
Aerosol Particles ◽  
Qualitative And Quantitative Analysis ◽  
Surface Enrichment ◽  
X Ray ◽  
Qualitative And Quantitative

AbstractQualitative and quantitative analysis of surface species on size-segregated atmospheric particulate collected in Antarctica during the 2010–11 summer was performed by X-ray photoelectron spectroscopy (XPS). This represents the first example of surface characterization of Antarctic aerosols. The size class with particle cut-off diameter of 3 μm was richest in terms of chemical elements. Peculiar findings of the application included detection of Ca (possibly surface-segregated) and surface enrichment of Mg. The determination of nitrate, ammonium and sulphate species on collection filters provides evidence for a possible advantage of XPS over more laborious techniques (e.g. ion chromatography). The presence of these species is in reasonable agreement with other recent reports from Antarctica.

Wear Behaviour of Thermal Spray Welded FeNi and CeO2 Composite Coatings

2011 ◽  
Vol 194-196 ◽  
pp. 363-366
Author(s):  
Bu Nv Liang ◽  
Biao Chen ◽  
Zhen Yu Zhang ◽  
Peng Lin Zhang
Keyword(s):  
Sliding Wear ◽  
Steel Substrate ◽  
Composite Coatings ◽  
Wear Behaviour ◽  
Flame Spray ◽  
Dry Conditions ◽  
Weight Loss Method ◽  
Loss Method ◽  
Wear Tests ◽  
Feni Alloy

FeNi alloy powders with and without 0.4 % CeO2were flame spray welded onto 1045 carbon steel substrate. Vickers microhardness profiles of the coatings were carried out. Sliding wear tests in dry conditions were carried out by means of weight-loss method for several applications in oil industries. For this purpose, Ni-based alloy and high chrome cast iron were used as compared materials. A scanning electron microscope(SEM) was used to analyze the wear phenomena of samples. The result showed that the hardness of the coatings can be improved by addition of 0. 4 % CeO2, and the anti-adhesion, anti-scratching, and plastic deformation resistance abilities of coatings are increased with the addition of CeO2.

Formation of Clinker Containing Lithium

2019 ◽  
Vol 955 ◽  
pp. 50-55 ◽  
Author(s):  
Theodor Staněk ◽  
Alexandra Rybová ◽  
Anežka Zezulová ◽  
Martin Boháč
Keyword(s):  
Optical Microscopy ◽  
Cooling Rate ◽  
Research Methods ◽  
Industrial Production ◽  
Cement Industry ◽  
Waste Material ◽  
X Ray Diffraction ◽  
Free Lime ◽  
X Ray ◽  
Different Types

Nowadays, in industrial production, lithium consumption is strongly increasing and it can be assumed that waste material with an increased content of this metal could also appear. One of the most important sectors where different types of waste can be utilized is the cement industry. Therefore, it is desirable to monitor the influence of lithium on formation and properties of the clinker. In the presented work, this effect was monitored in laboratory conditions up to 5 wt.% Li2O. X-ray diffraction, DTA and optical microscopy were employed as research methods. Among other things, it has been found that Li2O causes the decomposition of the alite, the major clinker phase, to a microcrystalline mixture of belite and free lime, depending on its content and clinker cooling rate.

Identification of Asbestos Fibres in a Water Sample by X-Ray Microanalysis

1975 ◽  
Vol 33 ◽  
pp. 274-275
Author(s):  
K. A. Brookes ◽  
D. Finbow ◽  
Madeleine Samuel
Keyword(s):  
Water Sample ◽  
Background Radiation ◽  
X Ray ◽  
Left Hand ◽  
Transmission Imaging ◽  
Different Types ◽  
Normal Specimen ◽  
Liquid Nitrogen Cooling ◽  
Normal Transmission ◽  
Additional Port

Investigation of the particulate matter contained in the water sample, revealed the presence of a number of different types and certain of these were selected for analysis.An A.E.I. Corinth electron microscope was modified to accept a Kevex Si (Li) detector. To allow for existing instruments to be readily modified, this was kept to a minimum. An additional port is machined in the specimen region to accept the detector, with the liquid nitrogen cooling dewar conveniently housed in the left hand cupboard adjacent to the microscope column. Since background radiation leads to loss in the sensitivity of the instrument, great care has been taken to reduce this effect by screening and manufacturing components that are near the specimen from material of low atomic number. To change from normal transmission imaging to X-ray analysis, the special 4-position specimen rod is inserted through the normal specimen airlock.

X-ray mapping without STEM

1994 ◽  
Vol 52 ◽  
pp. 508-509
Author(s):  
Judith M. Brock ◽  
Max T. Otten
Keyword(s):  
Life Science ◽  
Materials Science ◽  
Chemical Elements ◽  
Full Description ◽  
Scanning System ◽  
Elemental Distribution ◽  
X Ray ◽  
Transmission Electron ◽  
Distribution Of Elements ◽  
Made In

A knowledge of the distribution of chemical elements in a specimen is often highly useful. In materials science specimens features such as grain boundaries and precipitates generally force a certain order on mental distribution, so that a single profile away from the boundary or precipitate gives a full description of all relevant data. No such simplicity can be assumed in life science specimens, where elements can occur various combinations and in different concentrations in tissue. In the latter case a two-dimensional elemental-distribution image is required to describe the material adequately. X-ray mapping provides such of the distribution of elements.The big disadvantage of x-ray mapping hitherto has been one requirement: the transmission electron microscope must have the scanning function. In cases where the STEM functionality – to record scanning images using a variety of STEM detectors – is not used, but only x-ray mapping is intended, a significant investment must still be made in the scanning system: electronics that drive the beam, detectors for generating the scanning images, and monitors for displaying and recording the images.

DIRECTIONS OF IMPROVEMENT OF RISK MANAGEMENT SYSTEM IN THE FIELD OF LOGISTICS ACTIVITIES

2017 ◽  
Author(s):  
Elena Lytvynenko ◽  
◽  
Taisiya Kozlova ◽  
Keyword(s):  
Risk Management ◽  
Practical Experience ◽  
Logistics System ◽  
Systematic Analysis ◽  
Qualitative And Quantitative ◽  
Different Types ◽  
Rational Management ◽  
Enterprise Logistics ◽  
Risk Acceptability ◽  
Logistics Activity

The changeable and unpredictable development of the enterprises’ external environment is one of the appearance causes of various types of business activities' risks, including logistics. The purpose of this article is to develop recommendations on improving the risk management of enterprises’ logistics activities in the context of instability. Achieving this goal requires consideration of the main stages of this process regarding the logistics activities' risks, providing advices on improving the process of risk management of logistics orientation. The article explores the process of analyzing the logistics activities' risks of the enterprise. Proceeding from the theoretical provisions of management and summarizing the practical experience of research in the field of systematic analysis of the enterprises' logistics activities risks, there are traced the organization's peculiarities of such analysis, and the main directions of its further improvement are proposed. All actions in the article, which are related to the analysis of the risk of enterprise logistics activity, are proposed to carry out in a certain sequence in the article. This sequence is given in the form of a structural scheme of systematic analysis of the risks of the enterprise logistics activities. Based on the objectivity of the existence of logistics activities' risks and the need to ensure the rational management of them, the algorithm of the risk management in the enterprise logistics system covers the stages of risks' identification, their qualitative and quantitative assessment, diagnostics, assessment of risk acceptability and application of neutralization measures to unacceptable logistical risks. It is concluded that the logistics activities risks combine different types of risks of all components and elements both in the process of changing material, financial and information flows, as well as in the process of managing the risks arising in the logistics system

Processing of granite quarry solid waste into industrial high silica materials using leaching process with HCl concentration variation

2020 ◽  
Vol 11 (2) ◽  
pp. 43-50
Author(s):  
Yusup Hendronursito ◽  
Muhammad Amin ◽  
Slamet Sumardi ◽  
Roniyus Marjunus ◽  
Frista Clarasati ◽  
...  
Keyword(s):  
Particle Size ◽  
Rotational Speed ◽  
Inductively Coupled Plasma ◽  
Chemical Elements ◽  
Silica Content ◽  
X Ray ◽  
Concentration Variation ◽  
Leaching Process ◽  
Hcl Concentration ◽  
Granite Powder

This study was aimed to increase granite's silica content using the leaching process with HCl concentration variation. The granite used in this study came from Lematang, South Lampung. This study aims to determine the effect of variations in HCl concentration, particle size, and rotational speed on the crystalline phase and chemical elements formed in the silica product produced from granite. The HCl concentration variations were 6.0 M, 7.2 M, 8.4 M, and 9.6 M, the variation in particle size used was 270 and 400 mesh. Variations in rotational speed during leaching were 500 and 750 rpm. Granite powder was calcined at 1000 ºC for 2 hours. Characterization was performed using X-Ray Fluorescence (XRF), X-Ray Diffraction (XRD), and Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP- OES). The results showed that the silica content increased with increasing HCl concentration, the finer the particle size, and the higher the rotational speed. XRF analysis showed that the silica with the highest purity was leached with 9.6 HCl with a particle size of 400 mesh and a rotational speed of of 750 rpm, which was 73.49%. Based on the results above, by leaching using HCl, the Si content can increase from before. The XRD diffractogram showed that the granite powder formed the Quartz phase.

On the X-Ray Absorption Frequencies Characteristic of the Chemical Elements

1919 ◽  
Vol 14 (6) ◽  
pp. 522-524 ◽  
Author(s):  
William Duane ◽  
Takeo Shimizu
Keyword(s):  
Chemical Elements ◽  
X Ray ◽  
X Ray Absorption ◽  
Absorption Frequencies
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