Grain Refinement of Titanium Weld by Heterogeneous Nucleation

2008 ◽  
Vol 580-582 ◽  
pp. 21-24 ◽  
Author(s):  
Hidenori Terasaki ◽  
Yuichi Komizo ◽  
Fumihiro Nishino ◽  
Masahiko Ikeda
Keyword(s):  
Heterogeneous Nucleation ◽  
Laser Scanning ◽  
Laser Scanning Confocal Microscopy ◽  
In Situ Observation ◽  
Scanning Confocal Microscopy ◽  
Β Phase ◽  
Α Phase ◽  
In Situ Observations ◽  
Cp Ti

Microstructure formation of CP-Ti and TiB reinforced titanium were in-situ observed during the thermal cycle simulated for Tungsten Inert Gas (TIG) welding, by using laser scanning confocal microscopy. Under the in-situ observation of TiB reinforced titanium, heterogeneous nucleation of α-phase at inclusion was clearly detected and plate growth was shown in high timeresolution. Furthermore, it was observed that grain boundary of β -phase was pinned by the inclusions. Microstructure difference between pure and TiB reinforced titanium was explained based on those in-situ observations.

In-situ Observation of Surface Relief Formation and Disappearance during Order-Disorder Transition of Equi-atomic CuAu alloy using Laser Scanning Confocal Microscopy

2004 ◽  
Vol 842 ◽  
Author(s):  
Seiji Miura ◽  
Hiroyuki Okuno ◽  
Kenji Ohkubo ◽  
Tetsuo Mohri
Keyword(s):  
Surface Relief ◽  
Laser Scanning ◽  
Laser Scanning Confocal Microscopy ◽  
Confocal Scanning Laser Microscopy ◽  
Strain Effect ◽  
In Situ Observation ◽  
Stress Effect ◽  
Scanning Confocal Microscopy ◽  
Crystallographic Orientation Relationship

ABSTRACTIn-situ observation of the formation and disappearance of the surface relief associated with the twinning during the order-disorder transitions among CuAu-I (L10), CuAu-II (PAP) and disordered fcc phases was conducted using Confocal Scanning Laser Microscopy equipped with a gold image furnace. The Retro effect was confirmed in poly-crystal samples, however no evidence was found in single-crystal samples. Also observed in poly-crystal samples are that the disordering temperature detected by the disappearing of relieves is different from grain to grain, and that grain boundary cracking alleviates the Retro effect. The observed phenomena were explained based on the crystallographic orientation relationship among grains investigated by FESEM/EBSD in terms of the elastic strain effect around grain boundaries induced by transition. It was confirmed that in each grain the surface relieves correspond to a set of two {011} planes having a <100> axis perpendicular to both planes in common. It was also found that the larger the average strain of two neighboring grains is, the lower the transition temperature. This observation was explained by the stress effect on the stability of a phase.

Three-Dimensional Laser-Scanning Confocal Microscopy of In Situ Hybridization in the Skin

1994 ◽  
Vol 16 (1) ◽  
pp. 44-51 ◽  
Author(s):  
Stephen E. Mahoney ◽  
Stephen W. Paddock ◽  
Louis C. Smith ◽  
Dorothy E. Lewis ◽  
Madeleine Duvic
Keyword(s):  
In Situ Hybridization ◽  
Confocal Microscopy ◽  
Laser Scanning ◽  
Three Dimensional ◽  
Laser Scanning Confocal Microscopy ◽  
Scanning Confocal Microscopy

Analysis of the 355 Aluminium Alloy Microstructure for Application in Thixoforming

2019 ◽  
Vol 285 ◽  
pp. 277-282
Author(s):  
Leandro Cássio de Paula ◽  
Shun Tokita ◽  
Kota Kadoi ◽  
Hiroshige Inoue ◽  
Eugênio José Zoqui
Keyword(s):  
Aluminium Alloy ◽  
Laser Scanning ◽  
Ostwald Ripening ◽  
Phase Particle ◽  
Thermodynamic Characteristics ◽  
Laser Scanning Confocal Microscopy ◽  
Primary Phase ◽  
Raw Material ◽  
In Situ Observation

The 355 aluminium alloy is known to have excellent thermodynamic characteristics that render it suitable as a raw material for rheocasting and thixoforming. However, besides the controllable transition from solid to liquid phase, the refined microstructure required in the semisolid range is one of the key factors with a strong influence on the rheology of the material. This paper intends to analyse the in situ behaviour of the microstructure, in terms of morphological change, using high-temperature laser scanning confocal microscopy. The 355 alloy was prepared via conventional casting, and refined with a 30-s exposition via ultrasonic melt treatment (UST - 20 Hz, 2 kW). The material was reheated up to the thixoforming target temperature of 595 °C at which it was maintained for 0, 30, 60, 90, and 120 s, after which all the samples were cooled in water. The samples subjected to UST prior to the heat treatment were more refined in terms of microstructural evolution; they exhibited reduction in grain size (~107 ± 16 μm), smallest primary phase particle size (~81 ± 7 μm), and high circularity shape factor (~0.59 ± 0.19 μm). In situ observation methods were employed to analyse evolution mechanisms such as Ostwald ripening and coalescence.

scholarly journals An In Situ Hybridization Histochemistry Technique Allowing Simultaneous Visualization by the Use of Confocal Microscopy of Three Cellular mRNA Species in Individual Neurons

1998 ◽  
Vol 46 (6) ◽  
pp. 753-759 ◽  
Author(s):  
Michel Grino ◽  
Alfredo J. Zamora
Keyword(s):  
Confocal Microscopy ◽  
Laser Scanning ◽  
Simultaneous Detection ◽  
Laser Scanning Confocal Microscopy ◽  
Mrna Species ◽  
Scanning Confocal Microscopy ◽  
Detection Systems ◽  
Low Concentrations ◽  
Simultaneous Visualization

We present a specific and sensitive method for simultaneous detection of three mRNA species in individual neurons. The method relies on the use of riboprobes labeled with [35S]-UTP, digoxigenin-UTP, or biotin-UTP. The nonradioactive probes were sequentially revealed by incubation with anti-digoxigenin immunoglobulins or streptavidin conjugated to peroxidase, followed by the use of fluorochrome-labeled tyramides as peroxidase substrates. The radioactive probe was revealed by conventional autoradiography. There was no interaction among the different probes or the various detection systems. We demonstrate the use of this method by illustrating on laser scanning confocal microscopy the co-localization of the mRNAs coding for corticotropin-releasing factor (CRF), arginine vasopressin (AVP), or peptidylglycine α-amidating monooxygenase (PAM) in rat hypothalamic paraventricular nucleus (PVN) and its modulation by endogenous glucocorticoids. Our results suggest that this method could be used not only to study the regulation of the hypothalamo-pituitary-adrenal axis but also in various models in which mRNAs are present at low concentrations.

scholarly journals In situ localization of mitochondrial DNA replication in intact mammalian cells.

1996 ◽  
Vol 135 (4) ◽  
pp. 883-893 ◽  
Author(s):  
A F Davis ◽  
D A Clayton
Keyword(s):  
Mitochondrial Dna ◽  
Mammalian Cells ◽  
Laser Scanning ◽  
Laser Scanning Confocal Microscopy ◽  
Brdu Incorporation ◽  
Double Labeling ◽  
Scanning Confocal Microscopy ◽  
Mtdna Replication ◽  
Time Required

Nearly all of the known activities required for mitochondrial DNA (mtDNA) replication and expression are nuclear-encoded gene products, necessitating communication between these two physically distinct intracellular compartments. A significant amount of both general and specific biochemical information about mtDNA replication in mammalian cells has been known for almost two decades. Early studies achieved selective incorporation of the thymidine analog 5-Bromo-2-deoxy-Uridine (BrdU) into mtDNA of thymidine kinase-deficient (TK[-]) cells. We have revisited this approach from a cellular perspective to determine whether there exist spatiotemporal constraints on mtDNA replication. Laser-scanning confocal microscopy was used to selectively detect mtDNA synthesis in situ in cultured mammalian cells using an immunocytochemical double-labeling approach to visualize the incorporation of BrdU into mtDNA of dye-labeled mitochondria. In situ detection of BrdU-incorporated mtDNA was feasible after a minimum of 1-2 h treatment with BrdU, consistent with previous biochemical studies that determined the time required for completion of a round of mtDNA replication. Interestingly, the pattern of BrdU incorporation into the mtDNA of cultured mammalian cells consistently radiated outward from a perinuclear position, suggesting that mtDNA replication first occurs in the vicinity of nuclear-provided materials. Newly replicated mtDNA then appears to rapidly distribute throughout the dynamic cellular mitochondrial network.

scholarly journals Intermediate endocrine-acinar pancreatic cells in duct ligation conditions

1997 ◽  
Vol 273 (5) ◽  
pp. C1641-C1649 ◽  
Author(s):  
Eugenio Bertelli ◽  
Moïse Bendayan
Keyword(s):  
Laser Scanning ◽  
Secretory Granules ◽  
Laser Scanning Confocal Microscopy ◽  
Secretory Proteins ◽  
Zymogen Granules ◽  
Double Labeling ◽  
Scanning Confocal Microscopy ◽  
Pancreatic Cells ◽  
Duct Ligation

When tissues were subjected to 24 h of duct ligation, intermediate pancreatic cells simultaneously displaying endocrine and exocrine phenotypes appeared. Immunocytochemistry by laser scanning confocal microscopy revealed the appearance of a large number of these cells coexpressing insulin and amylase. These cells were located within the islets of Langerhans as well as in the acinar parenchyma. They were also detected in a culture system of isolated pancreatic cells. With the use of immunoelectron microscopy, two types of secretory granules were identified in these cells. One was insulin immunoreactive, whereas the other, resembling zymogen granules, contained amylase. Occasionally, some small granules displayed a double labeling for both secretory proteins. Numerous crinophagic bodies and autophagosomes containing insulin and/or amylase were also present. In situ hybridization, applied with the specific probes, confirmed the presence of both insulin and amylase mRNAs in these cells. Because duct ligation is known to induce insulin cell proliferation, the present results confirm that endocrine-acinar cells do appear in such condition and may represent intermediate steps in a transdifferentiating process.

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