Corrosion Prevention Methods

1999 ◽  
pp. 191-218
Keyword(s):  
Corrosion Prevention ◽  
Prevention Methods

Electrochemical Study of Stainless Steels in High Temperature Urea Solutions

CORROSION ◽  
1984 ◽  
Vol 40 (8) ◽  
pp. 387-393 ◽  
Author(s):  
K. Matsumoto ◽  
T. Shinohara
Keyword(s):  
High Temperature ◽  
Stainless Steels ◽  
Molar Ratio ◽  
Homogeneous Distribution ◽  
Corrosion Mechanism ◽  
Corrosion Prevention ◽  
Ammonia Content ◽  
Cr Content ◽  
Prevention Methods ◽  
Sufficient Oxygen

Abstract The corrosion of stainless steels in high temperature and high pressure urea solutions was studied by electrochemical measurements together with immersion tests to elucidate the corrosion mechanism and to rationalize the corrosion prevention methods. It was demonstrated that the corrosion of stainless steel was either active region dissolution, caused by the lack of dissolved oxygen, or dissolution near the transpassive region in process fluids with sufficient oxygen. High Cr/low Ni (or Ni-free)/Mo stainless steels were readily passivated. Stainless steels with high Cr content and/or with homogeneous distribution of Cr had superior resistance to corrosion near the transpassive region. As the temperature rose, the passivation current increased. At the same time, dissolution of oxygen into the simulated process fluids was more pronounced; therefore, high temperature was not necessarily unfavorable for passivation. Ammonia content in the process fluids strongly affected the passivation current; the current increased as the NH3:H2O molar ratio fell. By comparing the environmental variables in urea plants with the obtained data, guidelines for suitable corrosion prevention methods were developed.

As One Corrosion Prevention Engineer

2019 ◽  
Vol 68 (2) ◽  
pp. 35-35
Author(s):  
Kenkichi Tashiro
Keyword(s):  
Corrosion Prevention

Evaluations and Analysis of Malware Prevention Methods on Websites

2013 ◽  
Vol E96.B (12) ◽  
pp. 3091-3100
Author(s):  
Takeshi YAGI ◽  
Junichi MURAYAMA ◽  
Takeo HARIU ◽  
Hiroyuki OHSAKI
Keyword(s):  
Prevention Methods

Security Concern and Countermeasures for Cheating in Visual Cryptography

2018 ◽  
Vol 6 (8) ◽  
pp. 277
Author(s):  
Ekta Y
Keyword(s):  
Communication System ◽  
Visual Cryptography ◽  
Detection Methods ◽  
Information Communication ◽  
New Approach ◽  
The World ◽  
Visual Cryptography Scheme ◽  
Prevention Methods ◽  
Security Concern

As IT sector is ruling the world now,confidentiality and security of information has become the most important inseparable aspect in information communication system. Keeping in view the same, a new approach called Visual Cryptography (VC) has been suggested by many researchers but there are some limitations with this scheme and cheating is one of the main problem among them. This paper intends to show the basis of cheating in VC in terms of cheating process, its detection methods and its prevention methods suggested by various researchers along with their merits and demerits. Finally, a good Cheating Immune Visual Cryptography Scheme (CIVCS) has been discussed which states the properties to be adopted by every Visual Cryptography scheme to make it immune to cheating attacks.

The Effect of Secondary Metalworking Processes on Susceptibility of Aircraft to Catastrophic Failures and Prevention Methods

2013 ◽  
Vol 58 (4) ◽  
pp. 1207-1212
Author(s):  
E.S. Dzidowski
Keyword(s):  
Dynamic Recovery ◽  
Fatigue Cracks ◽  
Shear Bands ◽  
Adiabatic Shear ◽  
Deformation Mechanisms ◽  
Processing Maps ◽  
Adiabatic Shear Bands ◽  
Flow Localization ◽  
Catastrophic Failures ◽  
Prevention Methods

Abstract The causes of plane crashes, stemming from the subcritical growth of fatigue cracks, are examined. It is found that the crashes occurred mainly because of the negligence of the defects arising in the course of secondary metalworking processes. It is shown that it is possible to prevent such damage, i.e. voids, wedge cracks, grain boundary cracks, adiabatic shear bands and flow localization, through the use of processing maps indicating the ranges in which the above defects arise and the ranges in which safe deformation mechanisms, such as deformation in dynamic recrystallization conditions, superplasticity, globularization and dynamic recovery, occur. Thanks to the use of such maps the processes can be optimized by selecting proper deformation rates and forming temperatures.

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