The mineralogical, microstructural, chemical characteristics of Recently Formed Fulgurite in Kinmen, Taiwan

2020 ◽  
Author(s):  
Meng Ting-Ju ◽  
Kuo Li-Wei ◽  
Chen Chien-Chih ◽  
Huang Wen-Jeng ◽  
Chen Tze-Yuan
Keyword(s):  
Electron Microscope ◽  
Electrical Discharge ◽  
High Pressures ◽  
Hydrothermal Condition ◽  
High Energy ◽  
Optical Microscope ◽  
Granitic Rocks ◽  
Near Surface ◽  
Geological Evidence ◽  
Cg Lightning

<p>Lightning is a common high-energy phenomenon. In particular, cloud-to-ground lightning (CG lightning) generates shock wave and electrical discharge on the ground and forms the associated geological evidence including melting and shock lamella on rocks, termed fulgurites. Because lightning strikes on different protolith (cohesive or non-cohesive rocks), Pasek et al. (2012) divided the fulgurites into four types: (I) sand fulgurites, (ii) soil/clay fulgurites, (iii) calcic-soil fulgurites, and (iv) rock fulgurites. Compared with the reported fulgurites derived from non-cohesive rocks, the recognition of rock fulgurites was rare and remains unclear. Here we report the detailed characterization of rock fulgurites formed in a very recent CG lightning event with microanalytical methods including optical microscope, Field-Emission Scanning Electron Microscope (FESEM), Transmission Electron Microscope (TEM), regular and synchrotron X-ray Powder Diffraction (XRD), and Raman spectroscope. We also provide a CG lightning energy dissipation model constrained by the observed current values. The CG lightning event (the current value is ~ 162 kA) took place on granitic gneiss in Kimen county, Taiwan, on May. 7th, 2018. Our results show that the rock fulgurites were characterized with a black-to-brown thin (~10 μm in thickness) glassy crust with some vesicles covering on the host rock. Hydrous sulfates, including jarosites and gypsums, were recognized to locally deposit on fulgurites, likely suggesting the presence of hydrothermal condition in near-surface exposures after the cessation of the CG lightning. Planer deformation features derived from high pressures (up to several GPa) were found in k-feldspar located beneath the glassy crust, suggesting the presence of shock waves also on the surface. In addition, the estimated melting energy for the observed fulgurite (~20 m<sup>2</sup> in area with the thickness of 100 μm) is much less than one one-hundredth of the observed CG lightning. It supports the previous studies that documented most of the electrical discharge was dissipated into ground. Our study establishes a reference rock fulgurites data originated from CG lighting on granitic rocks set for future on-site drilling and presents an application of these data for studies of ancient rock fulgurite relicts.</p>

scholarly journals Track PVB membrane based on irradiation with high energy protons

e-Polymers ◽  
2009 ◽  
Vol 9 (1) ◽  
Author(s):  
Muhammad Shadman ◽  
Farhood Ziaie ◽  
Saeid Yeganegi ◽  
Behrooz Niazi ◽  
Farshid Ziaee ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Etching Rate ◽  
Chemical Properties ◽  
Polyvinyl Butyral ◽  
Porous Membrane ◽  
High Energy ◽  
Optical Microscope ◽  
Etching Technique ◽  
Scanning Electron

AbstractOne of the methods of polymeric material modification is based on the irradiation with accelerated ions. Chemical etching of ion tracks in polymers is a method which is widely used in the fabrication of micro/nano-structures with predetermined characteristics. For the present study polyvinyl butyral (PVB) porous membrane was prepared by track-etching technique. Commercially available PVB film was irradiated by 30 MeV energy protons to form latent tracks, and then etched chemically by potassium hydroxide (KOH) with the different normalities. The etching rate of PVB was related to the concentration of etching reagent, temperature and time. The porous size and shape were investigated by scanning electron microscope (SEM) after and before etching. Relationships in between the etching rate and the etching parameters were established from experimental data, and can be used to control the pore size of PVB track-etch membrane. The Pore sizes and their structures were evaluated by optical microscope (OM) and scanning electron microscope (SEM). The results have shown the micro/nano-pores formation in the PVB films. The physico-chemical properties of the irradiated samples were investigated and compared with the un-irradiated one using the FTIR and DSC and DTG systems, as well.

Void-Lattice Formation in Natural Fluorite by Electron Irradiation

1976 ◽  
Vol 34 ◽  
pp. 614-615 ◽  
Author(s):  
L.E. Murr
Keyword(s):  
Electron Microscope ◽  
Electron Irradiation ◽  
Heavy Ion ◽  
High Energy ◽  
Stoichiometric Ratio ◽  
Direct Observations ◽  
Transmission Electron ◽  
Anion Vacancies ◽  
Cation And Anion Vacancies ◽  
Lattice Formation

The production of void lattices in metals as a result of displacement damage associated with high energy and heavy ion bombardment is now well documented. More recently, Murr has shown that a void lattice can be developed in natural (colored) fluorites observed in the transmission electron microscope. These were the first observations of a void lattice in an irradiated nonmetal, and the first, direct observations of color-center aggregates. Clinard, et al. have also recently observed a void lattice (described as a high density of aligned "pores") in neutron irradiated Al2O3 and Y2O3. In this latter work, itwas pointed out that in order that a cavity be formed,a near-stoichiometric ratio of cation and anion vacancies must aggregate. It was reasoned that two other alternatives to explain the pores were cation metal colloids and highpressure anion gas bubbles.Evans has proposed that void lattices result from the presence of a pre-existing impurity lattice, and predicted that the formation of a void lattice should restrict swelling in irradiated materials because it represents a state of saturation.

New form of Transmission Cross Coefficient for High-Resolution Imaging

1990 ◽  
Vol 48 (1) ◽  
pp. 60-61
Author(s):  
Kazuo Ishizuka
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
Transmission Function ◽  
Incident Beam ◽  
Optical Microscope ◽  
Strong Interactions ◽  
Small Range ◽  
Specimen Thickness ◽  
Beam Direction ◽  
Diffracted Waves

It is well known that taking into account spacial and temporal coherency of illumination as well as the wave aberration is important to interpret an image of a high-resolution electron microscope (HREM). This occues, because coherency of incident electrons restricts transmission of image information. Due to its large spherical and chromatic aberrations, the electron microscope requires higher coherency than the optical microscope. On an application of HREM for a strong scattering object, we have to estimate the contribution of the interference between the diffracted waves on an image formation. The contribution of each pair of diffracted waves may be properly represented by the transmission cross coefficients (TCC) between these waves. In this report, we will show an improved form of the TCC including second order derivatives, and compare it with the first order TCC.In the electron microscope the specimen is illuminated by quasi monochromatic electrons having a small range of illumination directions. Thus, the image intensity for each energy and each incident direction should be summed to give an intensity to be observed. However, this is a time consuming process, if the ranges of incident energy and/or illumination direction are large. To avoid this difficulty, we can use the TCC by assuming that a transmission function of the specimen does not depend on the incident beam direction. This is not always true, because dynamical scattering is important owing to strong interactions of electrons with the specimen. However, in the case of HREM, both the specimen thickness and the illumination angle should be small. Therefore we may neglect the dependency of the transmission function on the incident beam direction.

Applications of Energy Beams in Material and Device Processing

1983 ◽  
Vol 23 ◽  
Author(s):  
G.J. Galvin ◽  
L.S. Hung ◽  
J.W. Mayer ◽  
M. Nastasi
Keyword(s):  
Ion Beam ◽  
High Energy ◽  
Ion Beams ◽  
Traditional Role ◽  
Near Surface ◽  
Device Processing ◽  
Composition Modification ◽  
Directed Energy ◽  
Transistor Fabrication

ABSTRACTEnergetic ion beams used outside the traditional role of ion implantation are considered for semiconductor applications involving interface modification for self-aligned silicide contacts, composition modification for formation of buried oxide layers in Si on insulator structures and reduced disorder in high energy ion beam annealing for buried collectors in transistor fabrication. In metals, aside from their use in modification of the composition of near surface regions, energetic ion beams are being investigated for structural modification in crystalline to amorphous transitions. Pulsed beams of photons and electrons are used as directed energy sources in rapid solidification. Here, we consider the role of temperature gradients and impurities in epitaxial growth of silicon.

scholarly journals Study on the Dissolution and Precipitation Behavior of Self-Designed (NbTi)C Nanoparticles Addition in 1045 Steel

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 184
Author(s):  
Hongwei Zhu ◽  
Haonan Li ◽  
Furen Xiao ◽  
Zhixiang Gao
Keyword(s):  
Tensile Strength ◽  
Electron Microscope ◽  
Optical Microscope ◽  
Cast Steels ◽  
Uniform Dispersion ◽  
The Matrix ◽  
Thermo Calc Software ◽  
Particle Strengthening ◽  
1045 Steel ◽  
Addition Amount

Self-designed (NbTi)C nanoparticles were obtained by mechanical alloying, predispersed in Fe powder, and then added to 1045 steel to obtain modified cast steels. The microstructure of cast steels was investigated by an optical microscope, scanning electron microscope, X-ray diffraction, and a transmission electron microscope. The results showed that (NbTi)C particles can be added to steels and occur in the following forms: original ellipsoidal morphology nanoparticles with uniform dispersion in the matrix, cuboidal nanoparticles in the grain, and microparticles in the grain boundary. Calculations by Thermo-Calc software and solubility formula show that cuboidal (NbTi)C nanoparticles were precipitated in the grain, while the (NbTi)C microparticles were formed by eutectic transformation. The results of the tensile strength of steels show that the strength of modified steels increased and then declined with the increase in the addition amount. When the addition amount was 0.16 wt.%, the modified steel obtained the maximum tensile strength of 759.0 MPa, which is an increase of 52% compared with to that with no addition. The hardness of the modified steel increased with the addition of (NbTi)C nanoparticles. The performance increase was mainly related to grain refinement and the particle strengthening of (NbTi)C nanoparticles, and the performance degradation was related to the increase in eutectic (NbTi)C.

Organoclay-reinforced polyethersulfone-modified epoxy-based hybrid nanocomposites

2011 ◽  
Vol 23 (7) ◽  
pp. 526-534 ◽  
Author(s):  
Yang Wang ◽  
Boming Zhang ◽  
Jinrui Ye
Keyword(s):  
Electron Microscopy ◽  
Fracture Toughness ◽  
Electron Microscope ◽  
Optical Microscope ◽  
Mechanical Analysis ◽  
Hybrid Nanocomposites ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Modified Epoxy ◽  
Scanning Electron

Hybrid nanocomposites were successfully prepared by the incorporation of polyethersulfone (PES) and organoclay into epoxy resin. They had higher fracture toughness than the prepared PES/epoxy blend and organoclay/epoxy nanocomposites. The microstructures of the hybrid nanocomposites were studied. They were comprised of homogeneous PES/epoxy semi-interpenetrating network (semi-IPN) matrices and organoclay micro-agglomerates made up of tactoid-like regions composed of ordered exfoliated organoclay with various orientations. The former was confirmed with dynamic mechanical analysis, scanning electron microscopy and transmission electron microscopy, while the latter was successfully observed with X-ray diffraction measurements, optical microscope, scanning electron microscope and transmission electron microscope. The improvement of their fracture toughness was due to the synergistic toughening effect of the PES and the organoclay and related to their microstructures.

Effect of Casting Overheat and Rolling Temperature on Morphology of Sulfide in 30MnVS Steel

2012 ◽  
Vol 457-458 ◽  
pp. 270-273
Author(s):  
Yi You Tu ◽  
Guo Zhong Li
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Continuous Casting ◽  
Optical Microscope ◽  
Rolling Temperature ◽  
Ferrite Content ◽  
Continuous Casting Slab ◽  
Intragranular Ferrite ◽  
Sulfide Segregation ◽  
Scanning Electron

Effect of superheat and initial rolling temperature on the morphology and distribution of sulfide in non quenched and tempered free cutting steel 30MnVS has been studied by optical microscope and scanning electron microscope. Results show that proper superheat and initial rolling temperature can turn rod-shaped sulfide into massive or globular sulfide，to alleviate sulfide segregation and pro-eutectoid ferrite distribution along the boundary of pearlite clusters in 30MnVS , increase the intragranular ferrite content and optimize the structure of continuous casting slab.

scholarly journals In-Situ Diagnostics at High Pressures: Ellipsometric and Rheed Studies of the Growth of Yba2Cu3O7

1997 ◽  
Vol 502 ◽  
Author(s):  
Dave H. A. Blank ◽  
Horst Rogalla
Keyword(s):  
Thin Films ◽  
High Pressures ◽  
High Vacuum ◽  
Pulsed Laser ◽  
Complex Oxide ◽  
High Energy ◽  
Diagnostic Tools ◽  
Heteroepitaxial Growth ◽  
Deposition Parameters

ABSTRACTPulsed Laser and Sputter Deposition are used for the fabrication of complex oxide thin films at relatively high oxygen pressures (up to 0.5 mBar). This high pressure hampers the application of a number of in-situ diagnostic tools. One of the exceptions is ellipsometry. Using this technique we studied in-situ the growth of off-axis sputtered Yba2Cu3O6+x thin films on (001) SrTiO3 as a function of the deposition parameters. Furthermore, the oxidation process from O(6) to O(7) has been studied by performing spectroscopic ellipsometry during isobaric cooling procedures.Another suitable in-situ monitoring technique for the growth of thin films is Reflection High Energy Electron Diffraction (RHEED). In general this is a (high) vacuum technique. Here, we present an RHEED-system in which we can observe clear diffraction patterns up to a deposition pressure of 0.5 mBar. The system has been used for in-situ monitoring of the heteroepitaxial growth of YBa2Cu3 06+x on SrTiO3 by pulsed laser deposition.

Analysis of an Axle Failure under Torsional Load

2016 ◽  
Vol 850 ◽  
pp. 101-106 ◽  
Author(s):  
Shu Mei Li ◽  
Jian Jun Yang ◽  
Wei Dong Zhang ◽  
August Chang ◽  
Cai Xia Zhang ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Failure Mechanism ◽  
Field Testing ◽  
Optical Microscope ◽  
Fatigue Lifetime ◽  
Torsional Load ◽  
Torsional Fatigue ◽  
Secondary Cracks ◽  
Scanning Electron

Premature fracture of an axle under torsional load occurred after a tracked military tank had experienced field testing for only 80 kilometers. Visual metallographic examinations were performed with optical microscope (OM) and scanning electron microscope (SEM). The investigation demonstrates that the premature fracture is caused by metallurgical problems inside the axle where the primary and secondary cracks originate, propagate, and eventually result in final catastrophic rupture through torsional fatigue. The failure mechanism is summarized and improvement of the fatigue lifetime for the axle is recommended.

scholarly journals ELECTRON MICROSCOPY OF CENTRIFUGED HYPHAE OF NEUROSPORA

1961 ◽  
Vol 9 (3) ◽  
pp. 609-617 ◽  
Author(s):  
M. Zalokar
Keyword(s):  
Electron Microscopy ◽  
Endoplasmic Reticulum ◽  
Electron Microscope ◽  
Optical Microscope ◽  
Granular Structure ◽  
Cell Physiology ◽  
Cell Structures ◽  
Light Area ◽  
Fat Bodies

Normal and centrifuged hyphae of Neurospora were studied with the electron microscope. The following cell structures could be identified: nuclei with nucleoli, mitochondria, endoplasmic reticulum, ribosomes, glycogen, fat bodies, vacuoles, and vesicles with an inner canalicular system, of unknown nature. In centrifuged hyphae, the glycogen layer appeared as a light area, with a slight indication of granular structure. The ribosome layer consisted of densely packed ribosomes without any membranes. The mitochondrial layer contained spaces filled with ribosomes. The nuclei were loosely packed, with endoplasmic reticulum between them. The "enchylema" layer was composed of vesicles belonging to the endoplasmic reticulum. The vacuolar layer was poorly preserved and consisted of double-walled vesicles. Fat appeared as stellate osmiophilic droplets. These observations were compared with previous observations under the optical microscope and their meaning for cell physiology was discussed.

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