Effects of discrete and simultaneous addition of SiC and Si3N4 on microstructural development of TiB2 ceramics

2021 ◽  
Vol 47 (3) ◽  
pp. 3520-3528 ◽  
Author(s):  
Van-Huy Nguyen ◽  
Seyed Ali Delbari ◽  
Zohre Ahmadi ◽  
Abbas Sabahi Namini ◽  
Quyet Van Le ◽  
...  
Keyword(s):  
Microstructural Development ◽  
Simultaneous Addition

Microstructural Development in Nb-Ti Multifilamentary Superconductors During Processing

1985 ◽  
Vol 43 ◽  
pp. 190-191
Author(s):  
A. W. West
Keyword(s):  
Heat Treatment ◽  
Critical Current Density ◽  
Copper Matrix ◽  
Wire Drawing ◽  
Heat Treatments ◽  
Microstructural Development ◽  
Final Size ◽  
Density Values ◽  
The Wire ◽  
Multifilamentary Superconductors

The influence of the filament microstructure on the critical current density values, Jc, of Nb-Ti multifilamentary superconducting composites has been well documented. However the development of these microstructures during composite processing is still under investigation.During manufacture, the multifilamentary composite is given several heat treatments interspersed in the wire-drawing schedule. Typically, these heat treatments are for 5 to 80 hours at temperatures between 523 and 573K. A short heat treatment of approximately 3 hours at 573K is usually given to the wire at final size. Originally this heat treatment was given to soften the copper matrix, but recent work has shown that it can markedly change both the Jc value and microstructure of the composite.

Processing and characterization of YBa2Cu3O7−x/Ag composites

1990 ◽  
Vol 48 (4) ◽  
pp. 46-47
Author(s):  
Jafar Javadpour ◽  
Bradley L. Thiel ◽  
Sarikaya Mehmet ◽  
Ilhan A. Aksay
Keyword(s):  
Composite System ◽  
Precursor Solution ◽  
Microstructural Development ◽  
Superconducting Properties ◽  
Practical Applications ◽  
Nitrate Precursor ◽  
Cold Pressed ◽  
Tape Cast ◽  
Composite Samples

Practical applications of bulk YBa2Cu3O7−x materials have been limited because of their inadequate critical current density (jc) and poor mechanical properties. Several recent reports have indicated that the addition of Ag to the YBa2Cu3O7−x system is beneficial in improving both mechanical and superconducting properties. However, detailed studies concerning the effect of Ag on the microstructural development of the cermet system have been lacking. Here, we present some observations on the microstructural evolution in the YBa2Cu3O7−x/Ag composite system.The composite samples were prepared by mixing various amounts (2.5 - 50 wt%) AgNO3 in the YBa2Cu3O7−x nitrate precursor solution. These solutions were then spray dried and the resulting powders were either cold pressed or tape cast. The microstructures of the sintered samples were analyzed using SEM (Philips 515) and an analytical TEM (Philips 430T).The SEM micrographs of the compacts with 2.5 and 50 wt% Ag addition sintered at 915°C (below the melting point of Ag) for 1 h in air are displayed in Figs. 1 and 2, respectively.

Fibrinogen and its Derivatives: Cofactors in the Intrinsic Generation of Thrombin

1976 ◽  
Vol 35 (02) ◽  
pp. 305-313 ◽  
Author(s):  
D.C Triantaphyllopoulos ◽  
L.T Ryan
Keyword(s):  
Factor Viii ◽  
Vitamin K ◽  
Bovine Serum ◽  
Thrombin Generation ◽  
Factor V ◽  
Simultaneous Addition ◽  
Lower Effect

SummaryThe simultaneous addition of suboptimal concentrations of factor VIII and intact or plas-min-lysed fibrinogen into mixtures of the vitamin K dependent factors, phospholipids, adsorbed bovine serum (supplier of factor V) and calcium, increased the amount of thrombin which was generated three to twenty times over the sum of the amounts which were generated when factor VIII, or fibrinogen, or its derivatives were added separately into the thrombin generating mixture. When factor VIII was added together with both fibrinogen and its derivatives, the amount of thrombin generated was even greater, about 130% larger than the amount which was generated in the presence of equal concentrations of only intact fibrinogen plus factor VIII. Addition of albumin instead of fibrinogen or its derivatives has a similar but significantly lower effect on thrombin generation. It appears, therefore, that both intact fibrinogen and its plasminolytic derivatives, singly or in combination, and to a lesser extent albumin, act as cofactors in the reaction which is regulated by factor VIII.

Interaction between parathyroid hormone and prostaglandin E1 on cyclic AMP metabolism in rat kidney

1980 ◽  
Vol 93 (3) ◽  
pp. 339-345 ◽  
Author(s):  
Naokazu Nagata ◽  
Yuriko Ono ◽  
Narimichi Kimura
Keyword(s):  
Parathyroid Hormone ◽  
Cyclic Amp ◽  
Adenylate Cyclase ◽  
Rat Kidney ◽  
Prostaglandin E ◽  
Cortical Tissue ◽  
Newborn Rat ◽  
Simultaneous Addition ◽  
Renal Cortical Tissue ◽  
Subsequent Addition

Abstract. The interaction between parathyroid hormone (PTH) and prostaglandin E1 (PGE1) in influencing cyclic AMP metabolism in rat renal cortical tissue was examined. PTH and PGE1 stimulated additively the adenylate cyclase activity in the homogenate of the tissue. Both PTH and PGE1 enhanced the level of cyclic AMP in the incubated renal cortical tissue, but the effect of their simultaneous addition did not exceed the effect induced by PTH alone. Cyclic AMP accumulated in the incubation medium by stimulation by PTH was decreased by the simultaneous addition of PGE1. When the tissue was pre-incubated for 30 min with 2 to 10 μg/ml of PGE1, the magnitude of the increase of cyclic AMP caused by PTH subsequently added was lessened. However, the response to PTH of adenylate cyclase preparation obtained from the homogenate of PGE1-pre-treated tissue was not decreased. When first PTH was added to the incubating renal cortical tissue, the subsequent addition of PGE1 accelerated the decrease of cyclic AMP content in the tissue and decreased the amount of cyclic AMP released from the tissue. The interaction of PTH and PGE1 on cyclic AMP metabolism in the renal cortical tissue was in contrast to that seen in newborn rat calvaria where PGE1 and PTH acted additively in enhancing the level of cyclic AMP.

Microstructural control of pitch matrix carbon-carbon composite by iodine treatment

1998 ◽  
Vol 13 (2) ◽  
pp. 302-307 ◽  
Author(s):  
H. Kajiura ◽  
Y. Tanabe ◽  
E. Yasuda ◽  
A. Kaiho ◽  
I. Shiota ◽  
...  
Keyword(s):  
Coal Tar ◽  
Carbon Composite ◽  
Coal Tar Pitch ◽  
Microstructural Development ◽  
Carbon Yield ◽  
Graphitic Structure ◽  
Matrix Microstructure ◽  
Iodine Treatment ◽  
Matrix Precursor ◽  
Microstructural Control

Matrix microstructure of a pitch-based carbon-carbon composite was controlled by an iodine treatment. Coal-tar pitch having the softening point of 101 °C was used as a matrix precursor. The iodine treatment was carried out on a pitch-impregnated specimen at 90 °C for 3–20 h. The specimen was carbonized at 800 °C and graphitized at 2000–3000 °C. The carbon yield increased from 73% to 93% by the iodine treatment. Microstructures of carbonized specimens changed from a flow type texture to a mosaic type one by the iodine treatment. The microstructural development to graphitic structure was suppressed by the iodine treatment.

Sign in / Sign up

Export Citation Format

Share Document