The influence of fusion temperature on the defect center concentration of GeO2glass

1983 ◽  
Vol 54 (9) ◽  
pp. 5394-5399 ◽  
Author(s):  
G. Kordas ◽  
R. A. Weeks ◽  
D. L. Kinser
Keyword(s):  
Fusion Temperature ◽  
Defect Center

scholarly journals A Model for Predicting Arsenic Volatilization during Coal Combustion Based on the Ash Fusion Temperature and Coal Characteristic

Energies ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 334
Author(s):  
Bo Zhao ◽  
Geng Chen ◽  
Zijiang Xiong ◽  
Linbo Qin ◽  
Wangsheng Chen ◽  
...  
Keyword(s):  
Coal Combustion ◽  
Power Plants ◽  
Combustion Temperature ◽  
Published Data ◽  
Fusion Temperature ◽  
Equilibrium Calculation ◽  
Arsenic Distribution ◽  
Ash Fusion Temperature ◽  
Close Relationship ◽  
Coal Type

Arsenic emission from coal combustion power plants has attracted increasing attention due to its high toxicity. In this study, it was found that there was a close relationship between the ash fusion temperature (AFT) and arsenic distribution based on the thermodynamic equilibrium calculation. In addition to the AFT, coal characteristics and combustion temperature also considerably affected the distribution and morphology of arsenic during coal combustion. Thus, an arsenic volatilization model based on the AFT, coal type, and combustion temperature during coal combustion was developed. To test the accuracy of the model, blending coal combustion experiments were carried out. The experimental results and published data proved that the developed arsenic volatilization model can accurately predict arsenic emission during co-combustion, and the errors of the predicted value for bituminous and lignite were 2.3–9.8%, with the exception of JingLong (JL) coal when combusted at 1500 °C.

scholarly journals Single Defect Center Scanning Near-Field Optical Microscopy on Graphene

Nano Letters ◽  
2013 ◽  
Vol 13 (7) ◽  
pp. 3152-3156 ◽  
Author(s):  
Julia Tisler ◽  
Thomas Oeckinghaus ◽  
Rainer J. Stöhr ◽  
Roman Kolesov ◽  
Rolf Reuter ◽  
...  
Keyword(s):  
Optical Microscopy ◽  
Near Field ◽  
Defect Center ◽  
Single Defect

Modification of Point Defects in Quartz for Device Applications

1983 ◽  
Vol 24 ◽  
Author(s):  
J. C. King ◽  
D. R. Koehler
Keyword(s):  
Frequency Control ◽  
Defect Center ◽  
Ir Studies ◽  
Device Applications ◽  
Temperature Ranges ◽  
Radiation Induced ◽  
Impurity Centers ◽  
Acoustic Loss ◽  
Quartz Crystal Resonators ◽  
Hostile Environments

ABSTRACTImpurity centers in quartz play a significant role in the behavior of precision crystal resonators subjected to ionizing radiation. The substitutional Al center, charge compensated by Na, Li, H or a hole, is now known to be the primary contributing factor in most radiation-induced effects. Acoustic loss measurements, ESR measurements, optical studies and IR studies of these defects, over extended temperature ranges, have contributed substantially to our understanding of the impurity centers' role. Radiation-induced frequency and acoustic loss changes in quartz crystal resonators are now understood in terms of the evolving character of the defect center in a radiation field. This understanding has prompted material modification efforts such as high temperature electrolysis and doping technologies which permit, for instance, the fabrication of frequency control devices that are little affected by hostile environments.

Research on Purification Technology of Ultra-Large Flake Graphite Based on Alkali-Acid Method

2021 ◽  
Vol 1036 ◽  
pp. 104-113
Author(s):  
Hong Fei Guo ◽  
Bao Chao ◽  
Zeng Qi Zhao ◽  
Ding Nan
Keyword(s):  
Carbon Content ◽  
High Purity ◽  
Raw Materials ◽  
Acid Leaching ◽  
Flake Graphite ◽  
Fixed Carbon ◽  
Fusion Temperature ◽  
Acid Method ◽  
Fixed Carbon Content ◽  
Flake Structure

Graphite is a strategically scarce resource, and the preparation of high-purity graphite is the prerequisite and basis for the application of graphite. In order to determine the optimal purification technology parameters of an ultra-large flake graphite mine pneumatic separation ore with a fixed carbon content of 77.69%, a particle size of mainly 10 to 40 mesh, and main impurities of calcium carbonate, iron oxide and silica , two additional experiments of acid method and alkali method were added on the basis of alkali-acid method, to investigate the purification effect of different technological processes and acid leaching times on graphite raw materials, as well as to analyze the retention extent of different methods and alkali fusion temperature on graphite ultra-large flake structure. The results show that all three methods can increase the fixed carbon content of graphite to above 99%. However, compared with the acid method and the alkali method, the alkali-acid method can obtain high-purity graphite while also better protecting the graphite's ultra-large flake structure. The optimal fusion temperature is 400 °C, the optimal acid leaching time is 30% sulfuric acid thrice and 5% hydrofluoric acid once. After purification, the fixed carbon content of the product exceeds 99.97%.

scholarly journals Determination of crystallization enthalpies of some organic peroxides by a differential isothermal calorimeter

2021 ◽  
pp. 90-94
Keyword(s):  
Supercooled Liquids ◽  
Sublimation Enthalpy ◽  
Residual Pressure ◽  
Heat Conducting ◽  
Dicumyl Peroxide ◽  
Organic Substances ◽  
Fusion Temperature ◽  
The Difference ◽  
Isothermal Calorimeter

We developed a method for determination of the crystallization enthalpy of organic substances in a heat-conducting calorimeter at a temperature close to 298 K. Crystallization was conducted in the MID-200 calorimeter using an ampoule technique. The volume of ampoules, which contain the supercooled liquids, was approximately 0.2 cm3. The residual pressure was 650 Pa to lessen the heat loss. A few crystals of the material under investigation were employed as the crystallization centers. Based on the results of the experiment, the crystallization enthalpies of dicumyl peroxide, peroxyoctanoic acid and di-tert-butylperoxy isophthalate were determined. The vaporization and sublimation enthalpies of peroxyoctanoic acid were assessed using an ampoule method in the calorimeter. It was established that dicumyl peroxide which was supercooled 14 K below the fusion temperature exhibited a 20% increase in crystallization enthalpy as compared with that calculated from the difference between vaporization and sublimation enthalpy. At the same time, the crystallization enthalpy of peroxyoctanoic acid supercooled by 5 K was equal to that calculated from the difference between vaporization and sublimation enthalpy within the limiting experimental error. The received data show that the proposed method is promising for determining the heat of crystallization of liquids that are able to exist in a supercooled state during some time.

scholarly journals Design and Fabrication of Friction Stir Welding End-Effector for an ABB IRB1410 Robot

2016 ◽  
Vol 5 (2) ◽  
pp. 98
Author(s):  
Santosh Vanama
Keyword(s):  
Friction Stir Welding ◽  
High Strength ◽  
Fusion Welding ◽  
Fusion Temperature ◽  
End Effector ◽  
Friction Stir ◽  
Aluminum Sheets ◽  
Operation Pressure ◽  
Welding Processes ◽  
Tool Rotation

<p>The paper propose modelling and fabrication of friction stir welding end-effector for ABB IRB1410 robot. A dynamically developing version of pressure welding processes, join material without reaching the fusion temperature called friction stir welding. As friction stir welding occurs in solid state, no solidification structures are created thereby eliminating the brittle and eutectic phase’s common to fusion welding of high strength aluminium alloys. In this paper, Friction stir welding is applied to aluminum sheets of 2 mm thickness. A prototype setup is developed to monitor the evolution of main forces and tool temperature during the operation. Pressure of a gripper plays a major role for tool rotation and developing torque.  Fabrication of the tool has done. Force calculations are done by placing the sensors on the outer surface of gripper. Methods of evaluating weld quality are surveyed as well.</p>

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