In situ developed laminates with large microstructural differences between layers of similar composition

2006 ◽  
Vol 41 (12) ◽  
pp. 3695-3700 ◽  
Author(s):  
Salvador Bueno ◽  
Carmen Baudín
Keyword(s):  
Similar Composition

Comparison of polyphenols and related enzymes in the capsule and nodal tumor of Nicotiana plants

1974 ◽  
Vol 52 (6) ◽  
pp. 1379-1385 ◽  
Author(s):  
S. J. Sheen ◽  
R. A. Andersen
Keyword(s):  
Cell Proliferation ◽  
Phenolic Compounds ◽  
Nicotiana Tabacum ◽  
Chlorogenic Acid ◽  
Dry Weight ◽  
In Situ Synthesis ◽  
Floral Tissue ◽  
Similar Composition ◽  
Tumor Tissues

Extracts of capsules of Nicotiana tabacum cv. Burley 21 and nodal tumors and capsules of a genetically tumor-prone amphiploid N. suaveolens × N. langsdorffii had a similar composition of phenolic compounds. Dihydroxyphenols, predominantly chlorogenic acid, accumulated to 4% and 13% of the dry weight in the young and old tumors, respectively. In situ synthesis of chlorogenic acid in tumor tissues was demonstrated by incorporation of L-phenylalanine-U-14C. Quantities of polyphenols also increased as floral tissue developed from fertilized flower to capsule. The immature capsule and tumor tissues contained more polyphenoloxidase but less peroxidase than the leaf. Peroxidase zymograms, soluble proteins, and alkaloids in tumor extracts resembled those in capsule extracts. It is suggested that these biochemical similarities may reflect a common mode for the regulation of cell proliferation in tobacco capsules and nodal tumors.

scholarly journals Laser Powder Bed Fusion of Metal Coated Copper Powders

Materials ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 3493 ◽  
Author(s):  
Viktor Lindström ◽  
Oleksii Liashenko ◽  
Kai Zweiacker ◽  
Serhii Derevianko ◽  
Vladyslav Morozovych ◽  
...  
Keyword(s):  
Copper Content ◽  
Copper Alloys ◽  
Lower Amount ◽  
Powder Bed Fusion ◽  
Laser Powder Bed Fusion ◽  
Powder Bed ◽  
Similar Composition ◽  
Copper Powders ◽  
High Copper Content

Laser powder bed fusion (L-PBF) of copper alloys with high copper content is difficult due to the high infrared reflectivity and thermal conductivity of these alloys. In this study a simple and scalable method for coating copper powder with tin and nickel is presented, and suggested as an alloying strategy for such alloys. The coated powders were processed in a commercial L-PBF-machine at various scanning speeds. The samples made from coated powders show a lower amount of porosity compared to samples made from in-situ alloyed powders of similar composition.

PECULIARITIES OF THE SYNTHESIS OF HIGH-TEMPERATURE CERAMICS TASI2–SIC, REINFORCED IN SITU BY DISCRETE SILICON CARBIDE NANOFIBERS

2018 ◽  
pp. 72-76
Author(s):  
S. Vorotilo ◽  
E. D. Polozova ◽  
E. A. Levashov
Keyword(s):  
Fracture Toughness ◽  
Silicon Carbide ◽  
High Temperature ◽  
Relative Density ◽  
Hot Pressing ◽  
Temperature Synthesis ◽  
Similar Composition ◽  
High Temperature Synthesis ◽  
Sic Ceramic

The possibility of the increase of the properties of ceramics in the TaSi2–SiC system via the reinforcement by the SiC nanofibers formed in situ in the combustion wave has been studied. For the formation of nanofibers as well as for increase of the exothermicity of the reaction mixtures, energetic additive PTFE (C2F4) was used. Using the method of self-propagating high-temperature synthesis of the mechanically activated mixtures, 70%TaSi2+30%SiC ceramic was produced, with SiC present as the round-shaped grains and as nanofibers. Ceramic specimens sintered by hot pressing were characterized by relative density up to 98 %, hardness 19,0–19,2 GPa and fracture toughness 7,5–7,8 MPa·m1/2, which is noticeably above the fracture toughness of the ceramic with similar composition produced without the PTFE additions.

Rendez vous with Saturn's rings

1984 ◽  
Vol 75 ◽  
pp. 743-759 ◽  
Author(s):  
Kerry T. Nock
Keyword(s):  
Solar Energy ◽  
Electric Propulsion ◽  
Power Source ◽  
Propulsion System ◽  
Low Thrust ◽  
Ring Plane ◽  
The Earth ◽  
Total Impulse ◽  
Saturn's Rings

ABSTRACTA mission to rendezvous with the rings of Saturn is studied with regard to science rationale and instrumentation and engineering feasibility and design. Future detailedin situexploration of the rings of Saturn will require spacecraft systems with enormous propulsive capability. NASA is currently studying the critical technologies for just such a system, called Nuclear Electric Propulsion (NEP). Electric propulsion is the only technology which can effectively provide the required total impulse for this demanding mission. Furthermore, the power source must be nuclear because the solar energy reaching Saturn is only 1% of that at the Earth. An important aspect of this mission is the ability of the low thrust propulsion system to continuously boost the spacecraft above the ring plane as it spirals in toward Saturn, thus enabling scientific measurements of ring particles from only a few kilometers.

The Use of Advanced Analytical Techniques for Characterization of the Chemical, Physical, and Crystallographic Nature of a Surface

1973 ◽  
Vol 31 ◽  
pp. 132-133 ◽  
Author(s):  
R. E. Herfert
Keyword(s):  
Surface Characterization ◽  
Analytical Techniques ◽  
X Ray Diffraction ◽  
Depth Of Penetration ◽  
X Ray ◽  
The Past ◽  
Transmission Electron ◽  
Scanning Electron

Studies of the nature of a surface, either metallic or nonmetallic, in the past, have been limited to the instrumentation available for these measurements. In the past, optical microscopy, replica transmission electron microscopy, electron or X-ray diffraction and optical or X-ray spectroscopy have provided the means of surface characterization. Actually, some of these techniques are not purely surface; the depth of penetration may be a few thousands of an inch. Within the last five years, instrumentation has been made available which now makes it practical for use to study the outer few 100A of layers and characterize it completely from a chemical, physical, and crystallographic standpoint. The scanning electron microscope (SEM) provides a means of viewing the surface of a material in situ to magnifications as high as 250,000X.

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