In-situ monitoring and ex-situ elasticity mapping of laser induced metal melting pool using ultrasound: Numerical and experimental approaches

This report describes aspects of our previous studies of the mechanochemical synthesis of charge transfer complexes of the electron donor tetrathiafulvalene, which are relevant to the use of laboratory X-ray powder diffraction for ex situ monitoring of mechanochemical reactions toward investigating their mechanisms. In particular, the reaction of tetrathiafulvalene and chloranil was studied under neat mechanochemical conditions and liquid-assisted grinding with diethyl ether (1 μL/mg). The product in both cases is the green tetrathiafulvalene chloranil polymorph and the mechanism of the redox reaction is presumably the same. However, while the kinetic profile of the neat mechanochemical synthesis was fitted with a second-order rate law, that of the overall faster liquid-assisted grinding reaction was fitted with the Ginstling-Brounshtein 3D diffusion-controlled model. Hence, the diffusional processes and mass transfer bringing the reactants together and separating them from products must be different. Diffraction measurements sensitive to crystalline phases and amorphous material, combined with in situ monitoring by spectroscopic techniques, will ultimately afford a better understanding of mechanochemical reaction mechanisms, a hot topic in mechanochemistry.

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In situ monitoring and ex situ TEM analyses of spinel (MgAl $$_2$$ 2 O $$_4$$ 4 ) growth between (111)-oriented periclase (MgO) substrates and Al $$_2$$ 2 O $$_3$$ 3 thin films

Journal of Materials Science ◽

10.1007/s10853-016-0130-2 ◽

2016 ◽

Vol 51 (19) ◽

pp. 8824-8844

Author(s):

L. C. Götze ◽

R. Milke ◽

I. Zizak ◽

R. Wirth

Keyword(s):

Thin Films ◽

In Situ Monitoring ◽

Ex Situ

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In-Situ and Ex-Situ Characterization of Femtosecond Laser-Induced Ablation on As2S3 Chalcogenide Glasses and Advanced Grating Structures Fabrication

Materials ◽

10.3390/ma12010072 ◽

2018 ◽

Vol 12 (1) ◽

pp. 72 ◽

Cited By ~ 4

Author(s):

Hongyang Wang ◽

Dongfeng Qi ◽

Xiaohan Yu ◽

Yawen Zhang ◽

Zifeng Zhang ◽

...

Keyword(s):

Melting Point ◽

Femtosecond Laser ◽

Laser Fluence ◽

Chalcogenide Glasses ◽

Heating Temperature ◽

Ex Situ ◽

Direct Writing ◽

Melting Pool ◽

Writing Technology

Femtosecond laser pulse of 800 nm wavelength and 150 fs temporal width ablation of As2S3 chalcogenide glasses is investigated by pump-probing technology. At lower laser fluence (8.26 mJ/cm2), the surface temperature dropping to the melting point is fast (about 43 ps), which results in a clean hole on the surface. As the laser fluence increases, it takes a longer time for lattice temperature to cool to the melting point at high fluence (about 200 ps for 18.58 mJ/cm2, about 400 ps for 30.98 mJ/cm2). The longer time of the surface heating temperature induces the melting pool in the center, and accelerates material diffusing and gathering surrounding the crater, resulting in the peripheral rim structure and droplet-like structure around the rim. In addition, the fabricated long periodic As2S3 glasses diffraction gratings can preserve with high diffraction efficiency by laser direct writing technology.

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Linking In Situ Melt Pool Monitoring to Melt Pool Size Distributions and Internal Flaws in Laser Powder Bed Fusion

Metals ◽

10.3390/met11111856 ◽

2021 ◽

Vol 11 (11) ◽

pp. 1856

Author(s):

Claudia Schwerz ◽

Lars Nyborg

Keyword(s):

Near Infrared ◽

In Situ Monitoring ◽

Ex Situ ◽

Process Conditions ◽

Powder Bed Fusion ◽

Laser Powder Bed Fusion ◽

Powder Bed ◽

Melt Pool ◽

Melt Pool Size

In situ monitoring of the melt pools in laser powder bed fusion (LPBF) has enabled the elucidation of process phenomena. There has been an increasing interest in also using melt pool monitoring to identify process anomalies and control the quality of the manufactured parts. However, a better understanding of the variability of melt pools and the relation to the incidence of internal flaws are necessary to achieve this goal. This study aims to link distributions of melt pool dimensions to internal flaws and signal characteristics obtained from melt pool monitoring. A process mapping approach is employed in the manufacturing of Hastelloy X, comprising a vast portion of the process space. Ex situ measurements of melt pool dimensions and analysis of internal flaws are correlated to the signal obtained through in situ melt pool monitoring in the visible and near-infrared spectra. It is found that the variability in melt pool dimensions is related to the presence of internal flaws, but scatter in melt pool dimensions is not detectable by the monitoring system employed in this study. The signal intensities are proportional to melt pool dimensions, and the signal is increasingly dynamic following process conditions that increase the generation of spatter.

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Raman scattering based strategies for quality control and process monitoring in electrodeposited CuIn(S,Se)2 solar cell technologies

MRS Proceedings ◽

10.1557/proc-1165-m02-03 ◽

2009 ◽

Vol 1165 ◽

Author(s):

Jacobo Álvarez-García ◽

Xavier Fontané ◽

Victor Izquierdo-Roca ◽

Alejandro Perez-Rodriguez ◽

Joan Ramón Morante ◽

...

Keyword(s):

Solar Cell ◽

Raman Scattering ◽

Process Monitoring ◽

In Situ Monitoring ◽

Ex Situ ◽

Secondary Phases ◽

Solar Cell Efficiency ◽

Cell Efficiency ◽

Spectral Contribution

AbstractThis work reports the use of strategies based on Raman scattering for process monitoring of electrodeposited based S rich CuIn(S,Se)2 solar cells. Main vibrational modes in the Raman spectra are sensitive to features related to the crystalline quality, chemical composition and presence of secondary phases in the chalcopyrite layers, being all these features relevant for the optoelectronic properties of the final devices. Ex-situ and in-situ measurements during the electrochemical step allow the direct assessment on the formation of Se rich secondary phases which are related to the stoichiometry of the grown precursors. The analysis of the relative intensity of the spectral contribution from these phases allows early detection of deviations of precursor stoichiometry in relation to the optimum composition range in terms of solar cell efficiency. The applicability of the technique for the in-situ monitoring of the electrodeposition process is also discussed

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Ex situ and in situ monitoring of the syntheses of thermochromic Schiff bases

CrystEngComm ◽

10.1039/c3ce42583e ◽

2014 ◽

Vol 16 (20) ◽

pp. 4162-4168 ◽

Cited By ~ 13

Author(s):

M. Zbačnik ◽

B. Kaitner

Keyword(s):

Schiff Bases ◽

In Situ Monitoring ◽

Ex Situ

This work presents in situ PXRD monitoring of the syntheses of thermochromic Schiff bases and a study of the mechanisms of their formation.

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Application of In Situ Liquid Cell Transmission Electron Microscopy in Corrosion Studies: A Critical Review of Challenges and Achievements

CORROSION ◽

10.5006/3369 ◽

2019 ◽

Vol 76 (1) ◽

pp. 4-17 ◽

Cited By ~ 5

Author(s):

Ali Kosari ◽

Henny Zandbergen ◽

Frans Tichelaar ◽

Peter Visser ◽

Herman Terryn ◽

...

Keyword(s):

Electron Microscopy ◽

Transmission Electron Microscopy ◽

Real Life ◽

In Situ Monitoring ◽

Ex Situ ◽

Transmission Electron ◽

Corrosion Studies ◽

Cell Transmission ◽

Liquid Cell

Identifying corrosion initiation events in metals and alloys demands techniques that can provide temporal and spatial resolution simultaneously. Transmission electron microscopy (TEM) enables one to obtain microstructural and chemical descriptors of materials at atomic/nanoscopic level and has been used in corrosion studies of many metal-electrolyte combinations. Conventionally, ex situ and quasi in situ TEM studies of pre- and post-corroded samples were performed, but possible experimental artifacts such as dehydrated surfaces might not fully represent the real interfacial conditions as compared to those when actually immersed in the electrolyte. Recent advances in liquid cell transmission electron microscopy (LC-TEM) allows for in situ monitoring morphological and even compositional evolutions in materials resulting from interaction with gas or liquid environments. Corrosion science, as a challenging field of research, can benefit from this unparalleled opportunity to investigate many complicated corroding systems in aqueous environments at high resolution. However, “real life” corrosion with LC-TEM is still not straightforward in implementation and there are limitations and challenging experimental considerations for conducting reliable examinations. Thus, this study has been devoted to discussing the challenges of in situ LC-TEM wherein state-of-the-art achievements in the field of relevance are reviewed.

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Monitoring mineral precipitation sequence of Lake Magadi soda lake: A multi-technical approach

10.5194/egusphere-egu21-4392 ◽

2021 ◽

Author(s):

Melese Getenet ◽

Juan Manuel García-Ruiz ◽

Franziska Emmerling ◽

Dominik Al-Sabbagh ◽

Fermín Otálora ◽

...

Keyword(s):

Electron Microscopy ◽

Soda Lake ◽

In Situ Monitoring ◽

Ex Situ ◽

Precipitation Sequence ◽

Technical Approach ◽

Mineral Precipitation ◽

X Ray ◽

Lake Magadi

Lake Magadi is a saline soda lake in East African Rift Valley, occupying the axial trough of Southern Kenyan Rift. Its fed by perennial saline hot/warm springs, which evolve into the soda and saline chemistry of the lake. The main processes thought to cause the enrichment of the lake in Na+, CO32-, Cl-, HCO3- and SO42- are evaporative concentration, mineral precipitation and fractional dissolution [1]. Lake Magadi is considered an analogous environment to the early Earth [2]. The high pH, silica and carbonate content of Lake Magadi allows the formation of silica and carbonate induced self-assembled mineral structures [3,4]. Revealing the mineral precipitation sequence of Lake Magadi have implications in understanding the geochemistry of evaporative rift settings and soda oceans. We have experimentally investigated the mineral precipitation sequence during evaporation at 25 &#176;C. The sequence of mineral precipitation was recorded by using in-situ video microscopy. The mineral patterns observed in video microscopies were identified by spectroscopic, diffraction and electron microscopy techniques. The mineralogy and elemental composition of the precipitates were determined by using Raman spectroscopy, powder X-ray diffractions and scanning electron microscopy coupled with energy dispersive X-ray analyser. The results of the ex-situ analyses were compared with the in-situ X-ray diffraction. In-situ X-ray diffractions were performed on acoustically levitated droplets in the &#956;Spot beamline at BESSY II synchrotron (Berlin, Germany). Finally, thermodynamic evaporation simulation was performed by using PHREEQC code with Pitzer database. Ex-situ and in-situ experiments revealed that mineral precipitation begins with trona, followed by halite and finally thermonatrite. In PHREEQC simulations, natron was observed instead of thermonatrite, suggesting the role of kinetics in the mineral assemblages. This multi-technical approach of in-situ monitoring and ex-situ characterization is a powerful approach to unveil mineral precipitation patterns and the resulting geochemical evolution in evaporative rift settings.Acknowledgments: We acknowledge funding from the European Research Council under grant agreement no. 340863, from the Ministerio de Econom&#237;a y Competitividad of Spain through the project CGL2016-78971-P and Junta de Andaluc&#237;a for financing the project P18-FR-5008. M.G. acknowledges Grant No. BES-2017-081105 of the Ministerio de Ciencia, Innovacion y Universidades of the Spanish government.References:[1] Eugster, H.P. (1970). Chemistry and origin of the brines of Lake Magadi, Kenya. Mineralogical Society of America Special Papers, 3, 213&#8211;235.[2] Kempe, S.; Degens, E.T. (1985). An early soda ocean?.&#160;Chem. Geol.&#160;&#160;53, 95&#8211;108[3] Getenet, M.; Garc&#237;a-Ruiz, J.M.; Verdugo-Escamilla, C.; Guerra-Tschuschke, I (2020). Mineral Vesicles and Chemical Gardens from Carbonate-Rich Alkaline Brines of Lake Magadi, Kenya, Crystals, 10, 467.[4] Garc&#237;a-Ruiz J.M., van Zuilen M.A., Bach W. (2020) Mineral self-organization on a lifeless planet. Phys Life Rev, 34&#8211;35,62&#8211;82

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Strained Silicon on Ultrathin Silicon-Germanium Virtual Substrates

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.108-109.463 ◽

2005 ◽

Vol 108-109 ◽

pp. 463-468 ◽

Cited By ~ 4

Author(s):

Klara Lyutovich ◽

Erich Kasper ◽

Michael Oehme ◽

Jens Werner ◽

Tatiana S. Perova

Keyword(s):

Silicon Germanium ◽

Growth Control ◽

Buffer Layers ◽

In Situ Monitoring ◽

Ex Situ ◽

Initial Growth ◽

Strained Si ◽

Dislocation Generation ◽

Temperature Ramp

Molecular beam epitaxy is employed for the growth of strained-Si layers on top of virtual substrates with highly-relaxed ultrathin SiGe buffers in a continuous procedure. An initial growth stage at a temperature-ramp down to below 200°C causes misfit-dislocation generation by nucleation from point defects and provides an early relaxation in the SiGe buffers. In situ monitoring is used for the growth control. Layer thicknesses and composition are proved by ex situ spectroscopic ellipsometry. %Raman investigations on the layer stacks reveal high degrees of relaxation (70-100%) in sub-100nm SiGe buffer layers containing from 12 to 42 % Ge. Stress in strained Si layers estimated by means of Raman-spectra shift is adjustable from 0.92 to 6.84 GPa by the Ge-content in virtual substrates. Surface morphology of strained Si and of relaxed SiGe buffers is smooth and crosshatch-free. Device test structures show substantial increase of carrier mobilities in nMOSFETs fabricated on these strained-Si layers.

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Anaerobical Biogeochemical Reactor to comprehencive processo of biological pesticides degradate at wetland soils in door.

Multi-Science Journal ◽

10.33837/msj.v1i13.624 ◽

2018 ◽

Vol 1 (13) ◽

pp. 356

Author(s):

Marco Aurélio Pessoa-de-Souza ◽

Alfredo Borges De-Campos

Keyword(s):

Design Methodology ◽

Chemical Engineering ◽

In Situ Monitoring ◽

Ex Situ ◽

Flooded Soils ◽

Controlled Environments ◽

Biological Concepts ◽

Environmental Technologies ◽

Organic Pesticides

The biogeochemical reactors are apparatus constructed to evaluations in controlled environments. When well-designed can be environmental technologies for in situ monitoring, as well as methodological support for ex situ analysis. The various models are based on knowledge in chemical engineering and includes chemical, physical and biological concepts, as well as the possible interactions between these basic fronts study. The objective of this work is to expose the possibilities of use of reactors in biogeochemical studies of degradation of organic pesticides in flooded soils and propose a design methodology for tests which have focused on anaerobic systems and degradation of organic pesticides.

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