scholarly journals Comparative Evaluation of Anti-Corrosion Coatings for NdFeB-Type Magnets with Respect to Performance and Recyclability via Hydrogen-Assisted Recycling (HPMS)

2021 ◽  
Vol 5 (1) ◽  
pp. 87
Author(s):  
Carlo Burkhardt ◽  
Antje Lehmann ◽  
Peter Fleissner ◽  
Laura Grau ◽  
Mirko Trautz ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Layer Thickness ◽  
Comparative Evaluation ◽  
Corrosion Test ◽  
Permanent Magnets ◽  
Microstructural Analysis ◽  
Video Monitoring ◽  
Icp Oes ◽  
Labeling System

Various anti-corrosion coatings used on commercially available NdFeB-type magnets were comparatively examined for their durability and suitability for magnet reprocessing by hydrogen-assisted recycling (HPMS). Layer thickness and structure were determined by systematic microstructural analysis, and a standardized corrosion test was used to assess the durability of each layer. Chemical composition of the coatings was analyzed using SEM/EDS and ICP-OES. HPMS behavior was investigated using in situ video monitoring. The results of the presented investigations are an important contribution for the implementation of a sorting and labeling system to support and facilitate a commercially viable recycling of permanent magnets on an industrial scale.

Studies on Mechanical Properties and Wear Behaviour of In Situ Al-TiC Composites

2011 ◽  
Vol 328-330 ◽  
pp. 1654-1658
Author(s):  
S. Jerome ◽  
Ashish Kumar ◽  
S.P. Kumaresh Babu ◽  
Balasubramanian Ravisankar
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Corrosion Test ◽  
Microstructural Analysis ◽  
Wear Behaviour ◽  
Monolithic Alloy ◽  
In Situ Method ◽  
Erosion Corrosion ◽  
Scanning Electron

In the present work, Al–TiC composites were synthesized by Flux Assisted Synthesis (FAS) route. In this in situ method the TiC particles are generated from the reaction between the mixture of K2TiF6 salt and graphite in the molten aluminium. The XRD peaks have confirmed the presence of the TiC and no other undesirable intermetallics have formed after reaction. After casting the composites were extruded and then aged. All the cast, extruded and aged composites samples have exhibited significant improvement in mechanical properties in comparison with the monolithic alloy. The erosion corrosion test have been performed and found that wear resistance of the composites have significantly improved by the presence of TiC particles. Optical and Scanning electron microscopy were used for microstructural analysis and XRD was used for phase analysis. Mechanical testes were performed as per the ASTM standards.

Structural Studies on Mitotic Spindle Fibres

1978 ◽  
Vol 36 (3) ◽  
pp. 615-626
Author(s):  
J.R. Mcintosh
Keyword(s):  
Chemical Composition ◽  
Mitotic Spindle ◽  
Structural Studies ◽  
Mitotic Apparatus ◽  
Chemical Studies ◽  
Medical Interest ◽  
Spindle Fibres

The mitotic apparatus is a structure of obvious biological and medical interest, but it has proved to be a difficult cellular machine to understand. The chemical composition of the spindle is only slightly elucidated, largely because of the difficulties in preparing useful isolates of the structure. Chemical studies of the mitotic spindle have been reviewed elsewhere (Mcintosh, 1977), and will not be discussed further here. One would think that structural studies on the mitotic apparatus (MA) in situ would be straightforward, but even with this approach there is some disagreement in the results obtained with various methods and by different investigators. In this paper I will review briefly the approaches which have been used in structural studies of the MA, pointing out the strengths and problems of each approach. I will summarize the principal findings of the different methods, and identify what seem to be fruitful avenues for further work.

Exciton dynamics in thick GaN MOVPE epilayers deposited on sapphire.

1997 ◽  
Vol 2 ◽  
Author(s):  
J. Allègre ◽  
P. Lefebvre ◽  
J. Camassel ◽  
B. Beaumont ◽  
Pierre Gibart
Keyword(s):  
Layer Thickness ◽  
Buffer Layers ◽  
Rate Equations ◽  
Time Resolved ◽  
Versus Layer ◽  
Level Model ◽  
Shallow Impurities ◽  
Aln Buffer ◽  
Time Resolved Photoluminescence

Time-resolved photoluminescence spectra have been recorded on three GaN epitaxial layers of thickness 2.5 μm, 7 μm and 16 μm, at various temperatures ranging from 8K to 300K. The layers were deposited by MOVPE on (0001) sapphire substrates with standard AlN buffer layers. To achieve good homogeneities, the growth was in-situ monitored by laser reflectometry. All GaN layers showed sharp excitonic peaks in cw PL and three excitonic contributions were seen by reflectivity. The recombination dynamics of excitons depends strongly upon the layer thickness. For the thinnest layer, exponential decays with τ ~ 35 ps have been measured for both XA and XB free excitons. For the thickest layer, the decay becomes biexponential with τ1 ~ 80 ps and τ2 ~ 250 ps. These values are preserved up to room temperature. By solving coupled rate equations in a four-level model, this evolution is interpreted in terms of the reduction of density of both shallow impurities and deep traps, versus layer thickness, roughly following a L−1 law.

scholarly journals An Atmospheric Origin for HCN-Derived Polymers on Titan

Processes ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 965
Author(s):  
Zoé Perrin ◽  
Nathalie Carrasco ◽  
Audrey Chatain ◽  
Lora Jovanovic ◽  
Ludovic Vettier ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Gas Phase ◽  
Formation Process ◽  
Upper Atmosphere ◽  
Gas Mixture ◽  
Space Probe ◽  
Atmospheric Haze ◽  
Formation And Evolution ◽  
Haze Formation

Titan’s haze is strongly suspected to be an HCN-derived polymer, but despite the first in situ measurements by the ESA-Huygens space probe, its chemical composition and formation process remain largely unknown. To investigate this question, we simulated the atmospheric haze formation process, experimentally. We synthesized analogues of Titan’s haze, named Titan tholins, in an irradiated N2–CH4 gas mixture, mimicking Titan’s upper atmosphere chemistry. HCN was monitored in situ in the gas phase simultaneously with the formation and evolution of the haze particles. We show that HCN is produced as long as the particles are absent, and is then progressively consumed when the particles appear and grow. This work highlights HCN as an effective precursor of Titan’s haze and confirms the HCN-derived polymer nature of the haze.

scholarly journals Comparison of the Concentration of Risk Elements in Alluvial Soils Determined by pXRF In Situ, in the Laboratory, and by ICP-OES

Agronomy ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 938
Author(s):  
Ladislav Menšík ◽  
Lukáš Hlisnikovský ◽  
Pavel Nerušil ◽  
Eva Kunzová
Keyword(s):  
Precision Agriculture ◽  
Alluvial Soil ◽  
Coefficient Of Determination ◽  
Fast Method ◽  
Agricultural Practice ◽  
Regression Equations ◽  
Icp Oes ◽  
Risk Elements ◽  
The Relationship

The aim of the study was to compare the concentrations of risk elements (As, Cu, Mn, Ni, Pb, Zn) in alluvial soil, which were measured by a portable X-ray fluorescence analyser (pXRF) in situ (FIELD) and in the laboratory (LABORATORY). Subsequently, regression equations were developed for individual elements through the method of construction of the regression model, which compare the results of pXRF with classical laboratory analysis (ICP-OES). The accuracy of the measurement, expressed by the coefficient of determination (R2), was as follows in the case of FIELD–ICP-OES: Pb (0.96), Zn (0.92), As (0.72), Mn (0.63), Cu (0.31) and Ni (0.01). In the case of LABORATORY–ICP-OES, the coefficients had values: Pb (0.99), Zn (0.98), Cu and Mn (0.89), As (0.88), Ni (0.81). A higher dependence of the relationship was recorded between LABORATORY–ICP-OES than between FIELD–ICP-OES. An excellent relationship was recorded for the elements Pb and Zn, both for FIELD and LABORATORY (R2 higher than 0.90). The elements Cu, Mn and As have a worse tightness in the relationship; however, the results of the model have shown its applicability for common use, e.g., in agricultural practice or in monitoring the quality of the environment. Based on our results, we can say that pXRF instruments can provide highly accurate results for the concentration of risk elements in the soil in real time for some elements and meet the principle of precision agriculture: an efficient, accurate and fast method of analysis.

scholarly journals Relationship between the Optical Properties and Chemical Composition of Urban Aerosol Particles in Lithuania

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Julija Pauraite ◽  
Kristina Plauškaitė ◽  
Vadimas Dudoitis ◽  
Vidmantas Ulevicius
Keyword(s):  
Optical Properties ◽  
Chemical Composition ◽  
Organic Aerosol ◽  
Single Scattering ◽  
Chemical Compositions ◽  
Spectra Analysis ◽  
Average Value ◽  
Aerosol Mass ◽  
In Situ Investigation

In situ investigation results of aerosol optical properties (absorption and scattering) and chemical composition at an urban background site in Lithuania (Vilnius) are presented. Investigation was performed in May-June 2017 using an aerosol chemical speciation monitor (ACSM), a 7-wavelength Aethalometer and a 3-wavelength integrating Nephelometer. A positive matrix factorisation (PMF) was used for the organic aerosol mass spectra analysis to characterise the sources of ambient organic aerosol (OA). Five OA factors were identified: hydrocarbon-like OA (HOA), biomass-burning OA (BBOA), more and less oxygenated OA (LVOOA and SVOOA, respectively), and local hydrocarbon-like OA (LOA). The average absorption (at 470 nm) and scattering (at 450 nm) coefficients during the entire measurement campaign were 16.59 Mm−1 (standard deviation (SD) = 17.23 Mm−1) and 29.83 Mm−1 (SD = 20.45 Mm−1), respectively. Furthermore, the absorption and scattering Angström exponents (AAE and SAE, respectively) and single-scattering albedo (SSA) were calculated. The average AAE value at 470/660 nm was 0.97 (SD = 0.16) indicating traffic-related black carbon (BCtr) dominance. The average value of SAE (at 450/700 nm) was 1.93 (SD = 0.32) and could be determined by the submicron particle (PM1) dominance versus the supermicron ones (PM > 1 µm). The average value of SSA was 0.62 (SD = 0.13). Several aerosol types showed specific segregation in the SAE versus SSA plot, which underlines different optical properties due to various chemical compositions.

Material Reliability of Low-Temperature Boron Deposition for PureB Silicon Photodiode Fabrication

MRS Advances ◽  
2018 ◽  
Vol 3 (57-58) ◽  
pp. 3397-3402 ◽  
Author(s):  
L.K. Nanver ◽  
K. Lyon ◽  
X. Liu ◽  
J. Italiano ◽  
J. Huffman
Keyword(s):  
High Temperature ◽  
Layer Thickness ◽  
Vapor Deposition ◽  
Dark Current ◽  
Deposition Temperature ◽  
Chemical Vapor ◽  
Silicon Photodiode ◽  
In Situ Methods ◽  
Deposition Conditions

ABSTRACTThe chemical-vapor deposition conditions for the growth of pure boron (PureB) layers on silicon at temperatures as low as 400°C were investigated with the purpose of optimizing photodiodes fabricated with PureB anodes for minimal B-layer thickness, low dark current and chemical robustness. The B-deposition is performed in a commercially-available Si epitaxial reactor from a diborane precursor. In-situ methods commonly used to improve the cleanliness of the Si surface before deposition are tested for a deposition temperature of 450°C and PureB layer thickness of 3 nm. Specifically, high-temperature baking in hydrogen, and exposure to HCl are tested. Both material analysis and electrical diode characterization indicate that these extra cleaning steps degrade the properties of the PureB layer and the fabricated diodes.

Alteration by Cerium Element on Primary and Eutectic Mg2Si Phases in Al-20%Mg2Si In Situ Composite

2015 ◽  
Vol 1125 ◽  
pp. 23-27 ◽  
Author(s):  
Nur Azmah Nordin ◽  
Saeed Farahany ◽  
T. Abubakar ◽  
Esah Hamzah
Keyword(s):  
Material Properties ◽  
Microstructural Analysis ◽  
Eutectic Cell ◽  
Characteristic Parameters ◽  
In Situ Composite ◽  
Melt Treatment ◽  
Morphology Effect ◽  
Polygonal Shape ◽  
Fibre Form

Owing to its beneficial material properties, Al-Mg2Si in-situ composite has recently received wide attention and application in the manufacture of automotive and aerospace components. Melt treatment of the in-situ composite with the addition of Ce has resulted in a change in the primary and eutectic Mg2Si phases to refined morphology, which would be expected to improve the mechanical properties of the composite. Characteristic parameters of Mg2Si particles have been investigated via thermal and microstructural analysis. This has revealed that the addition of 0.8wt.% Ce produced optimum refinement effects on Mg2SiP because the coarse structure has been changed to a polygonal shape and reduced in size. Similarly, the flake-like morphology of Mg2SiE has been transformed into a rod-like or fibre form in addition to reduction of the eutectic cell area. The result also showed an increase in nucleation temperature TN of Mg2SiP while depressed for Mg2SiE, which also corresponds to the refinement morphology effect.

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