Chemical Composition Control Technology

2005 ◽  
pp. 271-283
Author(s):  
Masayuki Miyashita ◽  
Tatsuhiro Yabune ◽  
Hirohisa Kikuyama ◽  
Jun Takano
Keyword(s):  
Chemical Composition ◽  
Control Technology ◽  
Composition Control

Active Chemistry Control for Coolant Helium Applying High-Temperature Gas-Cooled Reactors

2008 ◽  
Author(s):  
Nariaki Sakaba ◽  
Shimpei Hamamoto ◽  
Yoichi Takeda
Keyword(s):  
Heat Transfer ◽  
High Temperature ◽  
Heat Exchanger ◽  
Chemical Composition ◽  
Structural Integrity ◽  
Carbon Deposition ◽  
Control Technology ◽  
Equilibrium Study ◽  
Intermediate Heat Exchanger ◽  
High Temperature Gas

Lifetime extension of high-temperature equipment such as the intermediate heat exchanger of high-temperature gas-cooled reactors (HTGRs) is important from the economical point of view. Since the replacing cost will cause the increasing of the running cost, it is important to reduce replacing times of the high-cost primary equipment during assumed reactor lifetime. In the past, helium chemistry has been controlled by the passive chemistry control technology in which chemical impurity in the coolant helium is removed as low concentration as possible, as does Japan’s HTTR. Although the lifetime of high-temperature equipment almost depends upon the chemistry conditions in the coolant helium, it is necessary to establish an active chemistry control technology to maintain adequate chemical conditions. In this study, carbon deposition which could occur at the surface of the heat transfer tubes of the intermediate heat exchanger and decarburization of the high-temperature material of Hastelloy XR used at the heat transfer tubes were evaluated by referring the actual chemistry data obtained by the HTTR. The chemical equilibrium study contributed to clarify the algorism of the chemistry behaviours to be controlled. The created algorism is planned to be added to the instrumentation system of the helium purification systems. In addition, the chemical composition to be maintained during the reactor operation was proposed by evaluating not only core graphite oxidation but also carbon deposition and decarburization. It was identified when the chemical composition could not keep adequately, injection of 10 ppm carbon monoxide could effectively control the chemical composition to the designated stable area where the high-temperature materials could keep their structural integrity beyond the assumed duration. The proposed active chemistry control technology is expected to contribute economically to the purification systems of the future very high-temperature reactors.

Chemical composition control in the CVT method

1983 ◽  
Vol 63 (1) ◽  
pp. 185-190 ◽  
Author(s):  
K. Hayashi ◽  
T. Kobashi ◽  
M. Nakahira
Keyword(s):  
Chemical Composition ◽  
Composition Control

Yogurt — A Compositional Survey in the Greater Lansing Area1

1979 ◽  
Vol 42 (5) ◽  
pp. 424-426 ◽  
Author(s):  
M. L. RICHMOND ◽  
R. C. CHANDAN ◽  
C. M. STINE
Keyword(s):  
Standard Deviation ◽  
Chemical Composition ◽  
Product Category ◽  
Low Fat ◽  
Mean Values ◽  
Total Solids ◽  
Composition Control

Prompted by numerous consumer inquiries and several reports in the literature, this survey was undertaken to monitor the composition of yogurt in the mid-Michigan market. Forty-seven samples representing six brands were analyzed. Mean values ± standard deviation for the content of protein (Kjeldahl), fat (Mojonnier) and total solids (Mojonnier), pH and net weights were measured. The data are presented by product category, i.e. low-fat flavored, low-fat plain, full-fat flavored, full-fat plain, and cumulated for all samples. Wide variations in chemical composition were observed between and within brands surveyed. Mean values for all flavored samples surveyed (N = 42) were 4.34% protein, 2.34% fat, 25.88% total solids and 4.01 pH. Corresponding values for all plain samples surveyed were 5.68, 2.86, 16.90 and 4.23, respectively. The data show that 25% of all samples analyzed were greater than 6.6% overweight while 10.6% of the yogurts surveyed weighed less than the declared container net weight. Caloric values for flavored yogurts ranged widely. Mean caloric values for flavored, low-fat and full-fat brands were 106 and 121 cal/100 g, respectively. In general, the results indicate that commercial yogurt would benefit from closer composition control.

Chemical Composition Control of Evaporated Cu2ZnSnS4 Solar Cells

2016 ◽  
Vol 2 (2) ◽  
pp. 27-30
Author(s):  
Hongtao Cui ◽  
◽  
Chang-Yeh Lee ◽  
Sihong Gong ◽  
Xiaolei Liu ◽  
...  
Keyword(s):  
Solar Cells ◽  
Chemical Composition ◽  
Composition Control

Effect of Secondary Vacuum Treatment on Performance Characteristics of A516 Grade 65 Carbon Steel

2017 ◽  
Vol 1143 ◽  
pp. 38-44
Author(s):  
Anisoara Ciocan ◽  
Beatrice Tudor
Keyword(s):  
Chemical Composition ◽  
Vacuum Treatment ◽  
Vacuum Arc ◽  
Clean Steel ◽  
Composition Control ◽  
Steel Making ◽  
Secondary Refining ◽  
Metallic Inclusions ◽  
Before And After ◽  
Oil Gas

The purpose of this research is to analyze the making technology of clean steel used in the oil, gas and petrochemical industry. The steel was obtained into conventional electric arc furnace. To enhance the steel quality a secondary refining treatment was applied. The purity characteristics of the steel A516 Grade 65, before and after the treatment in the vacuum arc degassing equipment are discussed and compared. The deoxidation, desulphurisation in the presence of basic slag and degassing by injecting an inert gas and also by vacuum exposure are effective in reducing non-metallic inclusions and for chemical composition control. Data from 31 melts obtained in two industrial conditions are presented according to steel making parameters. The variation of chemical composition, especially of content of S, P, and the cleanliness of the steel in terms of content of non-metallic inclusions are analyzed.

SCC growth rate measurements and surface oxide film characterization on high SFE austenitic stainless steels in a simulated BWR water environment

2014 ◽  
Vol 1715 ◽  
Author(s):  
S. Ooki ◽  
T. Yonezawa ◽  
M. Watanabe ◽  
H. Kokawa
Keyword(s):  
Growth Rate ◽  
Stainless Steel ◽  
Chemical Composition ◽  
Oxide Film ◽  
Stainless Steels ◽  
Growth Rates ◽  
Oxidation Behavior ◽  
Water Environment ◽  
Austenitic Stainless Steels ◽  
Composition Control

ABSTRACTStress Corrosion Cracking (SCC) has been detected in Boiling Water Reactors (BWRs) on core shrouds and primary water re-circulation piping made of low carbon stainless steels. Material hardening strongly affects SCC propagation behavior, and SCC growth rates increase with increasing hardness of austenitic stainless steels caused by cold work or neutron irradiation.Research work has been conducted in the authors’ laboratories with the aim of improving SCC resistance using chemical composition control of stainless steels. It has been previously reported that high stacking fault energy (SFE) materials showed better SCC resistance than low SFE materials due to hardening being suppressed in high SFE materials. In the present study, SCC growth rate (CGR) tests were performed using 15% cold worked Types 316L and 25Cr-20Ni stainless steels in a simulated BWR water environment. The 25Cr-20Ni stainless steel used has high SFE value due to chemical composition control and measured SCC growth rates were lower than those of low SFE stainless steels.However, oxidation behavior is one of the more important factors influencing SCC of austenitic stainless steels in addition to material hardening behavior, and the influence of the chemical composition control necessary to increase SFE on oxidation behavior in BWR primary coolants is still unclear. In this study, therefore, immersion tests using Types 316L and 25Cr-20Ni stainless steel specimens were also conducted in the simulated BWR water environment. The surface oxide films on the specimens were then analyzed with micro-Raman spectroscopy and glow discharge optical emission spectroscopy in order to help clarify the oxidation behavior.The results of these tests and analyses showed that the NiFe2O4 content of the outer oxide layers on the high SFE stainless steels was higher than that on the low SFE stainless steels. The inner oxide film on the 25Cr-20Ni stainless steel also had a high chromium content.Based on the above results, SCC resistance and oxidation behavior of high SFE austenitic stainless steels in a simulated BWR water environment will be discussed.

scholarly journals Synthesis of epitaxial monolayer Janus SPtSe

2020 ◽  
Vol 4 (1) ◽  
Author(s):  
Roberto Sant ◽  
Maxime Gay ◽  
Alain Marty ◽  
Simone Lisi ◽  
Rania Harrabi ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Photoelectron Spectroscopy ◽  
Transition Metal Dichalcogenides ◽  
Single Layer ◽  
Grazing Incidence ◽  
Layer By Layer ◽  
Layer Transition ◽  
X Ray ◽  
Composition Control ◽  
Metal Dichalcogenides

AbstractJanus single-layer transition metal dichalcogenides, in which the two chalcogen layers have a different chemical nature, push chemical composition control beyond what is usually achievable with van der Waals heterostructures. Here, we report such a Janus compound, SPtSe, which is predicted to exhibit strong Rashba spin–orbit coupling. We synthetized it by conversion of a single-layer of PtSe2 on Pt(111) via sulfurization under H2S atmosphere. Our in situ and operando structural analysis with grazing incidence synchrotron X-ray diffraction reveals the process by which the Janus alloy forms. The crystalline long-range order of the as-grown PtSe2 monolayer is first lost due to thermal annealing. A subsequent recrystallization in presence of a source of sulfur yields a highly ordered SPtSe alloy, which is isostructural to the pristine PtSe2. The chemical composition is resolved, layer-by-layer, using angle-resolved X-ray photoelectron spectroscopy, demonstrating that Se-by-S substitution occurs selectively in the topmost chalcogen layer.

Development of Low-Cost LX70A Rod for Steel Cord

2011 ◽  
Vol 239-242 ◽  
pp. 2474-2478 ◽  
Author(s):  
Shu Wei Cao ◽  
Yong Lin Kang ◽  
Xin Jiang Wang ◽  
Qi Hang Han
Keyword(s):  
Chemical Composition ◽  
Control Structure ◽  
Low Cost ◽  
Technical Requirement ◽  
Performance Control ◽  
Composition Control ◽  
Wire Rod ◽  
Composition Segregation ◽  
Steel Cord ◽  
Inclusion Control

Steel cord has the higher technical requirement in the production of wire rod. And the higher requirement of the structure uniformity brings about the more difficulty for producing wire rod. Therefore, the procedure of rod for steel cord has been studied at Anyang Iron & Steel Group Co., Ltd. It has been investigated the low-cost production process, inclusion control, composition segregation, chemical composition control, structure performance control and application of LX70A rod for steel cord. The present research has significant value for the application of similar products.

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