The Role Of Microstructures And The Diffusion Of Hydrogen In A Plain Carbon Eutectoid Steel For Pressure Vessels

2012 ◽  
Author(s):  
Ronnie Higuchi Rusli
Keyword(s):  
Hydrogen Embrittlement ◽  
Room Temperature ◽  
Pressure Vessels ◽  
Electrochemical Technique ◽  
Eutectoid Steel ◽  
Chemical Pressure ◽  
Hydrogen Retention ◽  
Cold Worked ◽  
Diffusion Of Hydrogen

An electrochemical technique was used to measure the room temperature diffusivity and trapping of hydrogen in a 0.82%C steel for chemical pressure vessels in two micro structural conditions (a) the cold worked pearlitic state and (b) the hardened and tempered state. Trapping of hydrogen occurs in both structures but with more traps in the cold worked structure. Base on experimental results and observation, different hydrogen retention (trapping) behavior operates in the two structures. It was also found that patented and cold worked steels are much less susceptible to hydrogen induced embrittlement than similar steels in the hardened and tempered condition. Key words: Diffusivity of hydrogen; hydrogen embrittlement; cold–worked

The adsorption and diffusion of electrolytic hydrogen in palladium

1962 ◽  
Vol 270 (1340) ◽  
pp. 90-102 ◽  
Keyword(s):  
Temperature Dependence ◽  
Gas Phase ◽  
Room Temperature ◽  
Time Lag ◽  
Diffusion Constant ◽  
Electrochemical Technique ◽  
Instantaneous Rate ◽  
Electrolytic Hydrogen ◽  
And Diffusion ◽  
Diffusion Of Hydrogen

A sensitive electrochemical technique, which permits the recording of the instantaneous rate of permeation of electrolytic hydrogen through palladium, is described. Results were obtained under conditions required by theory for the diffusion of hydrogen with the use of electronic potentiostats. Analysis of the results shows the validity of the equations previously deduced for the diffusion of hydrogen. No anomalies in the diffusion have been found under these conditions. Thus the diffusion constant is found to be independent of thickness in the range 0·0035 to 0·054 cm. The permeation has been found to be inversely proportional to thickness as required by theory. The diffusion constant for a hydrogen poor α-palladium has been found to be 1·30 ± 0·20 x 10 -7 cm 2 s -1 at room temperature. Reasons for permeation anomalies reported in the literature for diffusion of hydrogen from the gas phase are discussed. Attention is drawn to errors in the classical time lag determination which unless corrected, can give rise to spurious thickness and temperature dependence of the diffusion constant.

Clustering-Triggered Efficient Room Temperature Phosphorescence from Nonconventional Luminophores

2019 ◽  
Author(s):  
Shuyuan Zheng ◽  
Taiping Hu ◽  
Xin Bin ◽  
Yunzhong Wang ◽  
Yuanping Yi ◽  
...  
Keyword(s):  
Room Temperature ◽  
High Efficiency ◽  
Spin Orbit Coupling ◽  
Design Rationale ◽  
Emission Mechanism ◽  
Room Temperature Phosphorescence ◽  
Electronic Interactions ◽  
Energy Gaps ◽  
Theoretical Results

Pure organic room temperature phosphorescence (RTP) and luminescence from nonconventional luminophores have gained increasing attention. However, it remains challenging to achieve efficient RTP from unorthodox luminophores, on account of the unsophisticated understanding of the emission mechanism. Here we propose a strategy to realize efficient RTP in nonconventional luminophores through incorporation of lone pairs together with clustering and effective electronic interactions. The former promotes spin-orbit coupling and boost the consequent intersystem crossing, whereas the latter narrows energy gaps and stabilizes the triplets, thus synergistically affording remarkable RTP. Experimental and theoretical results of urea and its derivatives verify the design rationale. Remarkably, RTP from thiourea solids with unprecedentedly high efficiency of up to 24.5% is obtained. Further control experiments testify the crucial role of through-space delocalization on the emission. These results would spur the future fabrication of nonconventional phosphors, and moreover should advance understanding of the underlying emission mechanism.<br>

SAE 1025

Alloy Digest ◽  
1987 ◽  
Vol 36 (9) ◽  
Keyword(s):  
Fracture Toughness ◽  
Carbon Steel ◽  
Heat Treating ◽  
Plain Carbon Steel ◽  
General Purpose ◽  
Pressure Vessels ◽  
Permanent Mold ◽  
Steel Mills ◽  
Cold Worked ◽  
Permanent Mold Castings

Abstract SAE 1025 is a plain carbon steel for general-purpose construction and engineering. It is used in the hot-worked, cold-worked, normalized or water-quenched-and-tempered condition. It also is carburized and used for case-hardened parts. Its many uses include bolts, forgings, axles, machinery components, cold-extruded parts, pressure vessels, case-hardened parts, chain and sprocket assemblies, spinning tools and permanent-mold castings. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness. It also includes information on corrosion resistance as well as forming, heat treating, machining, joining, and surface treatment. Filing Code: CS-114. Producer or source: Carbon steel mills.

Sewage sludge as a precursor of adsorbents/catalysts for environmental applications

2007 ◽  
Vol 2 (1) ◽  
Author(s):  
A. Ros ◽  
C. Canals-Batlle ◽  
M.A. Lillo-Ródenas ◽  
E. Fuente ◽  
M. A. Montes-Morán ◽  
...  
Keyword(s):  
Sewage Sludge ◽  
Room Temperature ◽  
Waste Water Treatment ◽  
Textural Properties ◽  
Active Species ◽  
Elemental Sulphur ◽  
Gaseous Emissions ◽  
Removal Experiments ◽  
Catalytically Active

This paper focuses on the valorisation of solid residues obtained from the thermal treatment of sewage sludge. In particular, sewage sludge samples were collected from two waste water treatment plants (WWTPs) with different sludge line basic operations. After drying, sludges were heated up to 700 °C in appropriate ovens under diluted air (gasification) and inert (pyrolysis) atmospheres. The solids obtained, as well as the dried (raw) sludges, were characterised to determine their textural properties and chemical composition, including the speciation of their inorganic fraction. All the materials under study were employed as adsorbents/catalysts in H2S removal experiments at room temperature. It was found that, depending on the particular sludge characteristics, outstanding results can be achieved both in terms of retention capacities and selectivity. Some of the solids outperform commercially available sorbents specially designed for gaseous emissions control. In these adsorbents/catalysts, H2S is selectively oxidised to elemental sulphur most likely due to the presence of inorganic, catalytically active species. The role of the carbon-enriched part on these solids is also remarked.

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