scholarly journals Highly Disordered Ionic Distribution in α‐Dicalcium Silicate for Structure Relaxation

2021 ◽  
Author(s):  
Masanori Suzuki ◽  
Norimasa Umesaki ◽  
Yoshiki Ishii
Keyword(s):  
Dicalcium Silicate ◽  
Structure Relaxation ◽  
Ionic Distribution

Microstructural characterization of laser-melted/roller-quenched dicalcium silicate

1988 ◽  
Vol 46 ◽  
pp. 582-583
Author(s):  
C. J. Chan ◽  
K. R. Venkatachari ◽  
W. M. Kriven ◽  
J. F. Young
Keyword(s):  
Particle Size ◽  
Raw Materials ◽  
Shape Change ◽  
Microstructural Characterization ◽  
Particle Size Effect ◽  
Dicalcium Silicate ◽  
Laser Melting ◽  
Uniform Size ◽  
Cell Shape Change ◽  
Wide Range

Dicalcium silicate (Ca2SiO4) is a major component of Portland cement. It has also been investigated as a potential transformation toughener alternative to zirconia. It has five polymorphs: α, α'H, α'L, β and γ. Of interest is the β-to-γ transformation on cooling at about 490°C. This transformation, accompanied by a 12% volume increase and a 4.6° unit cell shape change, is analogous to the tetragonal-to-monoclinic transformation in zirconia. Due to the processing methods used, previous studies into the particle size effect were limited by a wide range of particle size distribution. In an attempt to obtain a more uniform size, a fast quench rate involving a laser-melting/roller-quenching technique was investigated.The laser-melting/roller-quenching experiment used precompacted bars of stoichiometric γ-Ca2SiO4 powder, which were synthesized from AR grade CaCO3 and SiO2xH2O. The raw materials were mixed by conventional ceramic processing techniques, and sintered at 1450°C. The dusted γ-Ca2SiO4 powder was uniaxially pressed into 0.4 cm x 0.4 cm x 4 cm bars under 34 MPa and cold isostatically pressed under 172 MPa. The γ-Ca2SiO4 bars were melted by a 10 KW-CO2 laser.

Investigation on a New Hydraulic Cementitious Binder Made from Phosphogypsum

2013 ◽  
Vol 864-867 ◽  
pp. 1923-1928
Author(s):  
Yue Xu ◽  
Jian Xi Li ◽  
Li Li Kan
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Active Carbon ◽  
High Strength ◽  
Tricalcium Silicate ◽  
Dicalcium Silicate ◽  
Cementitious Material ◽  
Saturation Ratio ◽  
Tricalcium Aluminate ◽  
Cementitious Binder

A new kind of high strength cementitious material is made from phosphogypsum (PG), active carbon and fly-ash. Through the orthogonal research, it was showed that the calcination temperature, retention time, dosage of active carbon and fly ash on the compressive strength of cementitious binder are the most important. The result also showed that, in the conditions of temperature 1200°C, time retention 30 min, dosage of active carbon 10%, dosage of fly ash 5%, the compressive strength of the cementitious material for 3d and 28d could reach to 46.35MPa and 92.70MPa, the content of sulfur trioxide was 11.60% accordingly. A lot of active mineral materials, such as dicalcium silicate, tricalcium silicate, tricalcium aluminate were formed in the calcination. The C-S-H gel, calcium hydroxide and ettringite were found in 3d and 28d hydrates. It is found that the lime saturation ratio and silica modulus need to be control between 0.40~0.65 and 4~8 in order to produce high strength cementitious material.

scholarly journals Melatonin Successfully Rescues the Hippocampal Molecular Machinery and Enhances Anti-oxidative Activity Following Early-Life Sleep Deprivation Injury

Antioxidants ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 774
Author(s):  
Hung-Ming Chang ◽  
Hsing-Chun Lin ◽  
Hsin-Lin Cheng ◽  
Chih-Kai Liao ◽  
To-Jung Tseng ◽  
...  
Keyword(s):  
Sleep Deprivation ◽  
Early Life ◽  
Cognitive Activity ◽  
Oxidative Activity ◽  
Protective Effects ◽  
Long Term Effects ◽  
Ionic Distribution ◽  
Melatonin Administration ◽  
Molecular Machinery ◽  
Underlying Mechanisms

Early-life sleep deprivation (ESD) is a serious condition with severe cognitive sequelae. Considering hippocampus plays an essential role in cognitive regulation, the present study aims to determine whether melatonin, a neuroendocrine beard with significant anti-oxidative activity, would greatly depress the hippocampal oxidative stress, improves the molecular machinery, and consequently exerts the neuro-protective effects following ESD. Male weanling Wistar rats (postnatal day 21) were subjected to ESD for three weeks. During this period, the animals were administered normal saline or melatonin (10 mg/kg) via intraperitoneal injection between 09:00 and 09:30 daily. After three cycles of ESD, the animals were kept under normal sleep/wake cycle until they reached adulthood and were sacrificed. The results indicated that ESD causes long-term effects, such as impairment of ionic distribution, interruption of the expressions of neurotransmitters and receptors, decreases in the levels of several antioxidant enzymes, and impairment of several signaling pathways, which contribute to neuronal death in hippocampal regions. Melatonin administration during ESD prevented these effects. Quantitative evaluation of cells also revealed a higher number of neurons in the melatonin-treated animals when compared with the saline-treated animals. As the hippocampus is critical to cognitive activity, preserving or even improving the hippocampal molecular machinery by melatonin during ESD not only helps us to better understand the underlying mechanisms of ESD-induced neuronal dysfunction, but also the therapeutic use of melatonin to counteract ESD-induced neuronal deficiency.

Structure Relaxation at Liquid–Solid Interfaces

1970 ◽  
Vol 53 (2) ◽  
pp. 798-800 ◽  
Author(s):  
Narendra N. Roy ◽  
G. D. Halsey
Keyword(s):  
Structure Relaxation

scholarly journals EFFECTS OF AZIDE AND CHLORETONE ON THE SODIUM AND POTASSIUM CONTENTS AND THE RESPIRATION OF FROG SCIATIC NERVES

1958 ◽  
Vol 41 (5) ◽  
pp. 959-988 ◽  
Author(s):  
W. P. Hurlbut
Keyword(s):  
Oxygen Consumption ◽  
Respiratory Depression ◽  
Conduction Block ◽  
Slow Conduction ◽  
Ionic Distribution ◽  
Rate Of Oxygen Consumption ◽  
Sciatic Nerves ◽  
Time Courses ◽  
Sodium And Potassium

Azide (0.2 to 5.0 mM) and chloretone (2.0 to 15.0 mM) reversibly inhibited 20 to 90 per cent of the resting respiration of frog sciatic nerves, and caused a loss of potassium and a gain of sodium in this tissue. The changes in ionic contents that developed after 5 or 10 hours were roughly correlated with the degree of respiratory depression, but the time courses of these changes were different with the two reagents. In azide these changes appeared to begin immediately, while in chloretone, at concentrations between 3.0 and 5.0 mM, the ionic shifts developed after a delay of several hours. Fifteen millimolar chloretone produced immediate changes in ionic contents several times greater than those produced by anoxia. The changes in ionic distribution produced in 5 hours by anoxia, 5.0 mM azide, or 5.0 mM chloretone were at least partially reversible; those produced by 15.0 mM chloretone were irreversible. With the exception of 15.0 mM chloretone the ionic shifts produced by these reagents may be due primarily to the depression of the respiration, although there are indications that azide acts, in addition, by another pathway. Concentrations of azide or chloretone that depressed the resting rate of oxygen consumption more than 50 per cent produced a slow conduction block, while 15.0 mM chloretone blocked conduction within 15 minutes.

Highly Reactive ?-Dicalcium Silicate

2002 ◽  
Vol 85 (9) ◽  
pp. 2171-2176 ◽  
Author(s):  
Nakshatra B. Singh ◽  
Sarita Rai ◽  
Neelam Singh
Keyword(s):  
Dicalcium Silicate

Rational design and fabrication of a β-dicalcium silicate-based multifunctional cement with potential for root canal filling treatment

2014 ◽  
Vol 2 (24) ◽  
pp. 3830-3838 ◽  
Author(s):  
Xianyan Yang ◽  
Min Liu ◽  
Yu Zhao ◽  
Hongyu Jia ◽  
Sanzhong Xu ◽  
...  
Keyword(s):  
Root Canal ◽  
Rational Design ◽  
Biological Properties ◽  
Dicalcium Silicate ◽  
Root Canal Therapy ◽  
Root Canal Filling ◽  
Physicochemical And Biological Properties

Gypsum-introduced, CaO-rich dicalcium silicate-based cements exhibit multifunctional physicochemical and biological properties and meet some challenging criteria in root canal therapy.

Effect of strontium oxide on the formation mechanism of dicalcium silicate with barium oxide and sulfur trioxide

2015 ◽  
Vol 27 (7) ◽  
pp. 381-387 ◽  
Author(s):  
Jie Zhang ◽  
Chenchen Gong ◽  
Shoude Wang ◽  
Lingchao Lu ◽  
Xin Cheng
Keyword(s):  
Formation Mechanism ◽  
Sulfur Trioxide ◽  
Barium Oxide ◽  
Dicalcium Silicate ◽  
Strontium Oxide
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