The effects of long term operation and system conditions on the dielectric capability and insulation coordination of large power transformers

The paper presents results of studies on the crystallite sizes of oxide layer formed during a long-term operation on 10CrMo9-10 steel at an elevated temperature (T = 545° C, t = 200,000 h). This value was determined by a method based on analysis of the diffraction line profile, according to a Scherrer formula. The oxide layer was studied on a surface and a cross-section at the outer and inner site on the pipe outlet, at the fire and counter-fire wall of the tube. X-ray studies were carried out on the surface of a tube, then the layer’s surface was polished and the diffraction measurements repeated to reveal differences in the originated oxides layer.

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Energy performance of large power transformers (Um > 36 kV or Sr ≥ 40 MVA)

10.3403/30293685 ◽

2015 ◽

Keyword(s):

Energy Performance ◽

Power Transformers ◽

Large Power

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Retention and expression of recombinant plasmids in suspended and biofilm-bound bacteria degrading trichloroethene (TCE)

Water Science & Technology ◽

10.2166/wst.1997.0346 ◽

1997 ◽

Vol 36 (10) ◽

pp. 1-8 ◽

Cited By ~ 1

Author(s):

James D. Bryers ◽

Robert R. Sharp

Keyword(s):

Biofilm Reactor ◽

Bacterial Biofilm ◽

Laboratory Evaluation ◽

Recombinant Bacteria ◽

Suitable Host ◽

Term Operation ◽

Open Environment ◽

Recombinant Microorganisms ◽

Extracellular Polymer

Exposure of plasmid recombinant microorganisms to an open environment, either inadvertently or intentionally, requires research into those fundamental processes that govern plasmid retention, transfer and expression. In the open environment, a majority of the microbial activity occurs associated with an interface, within thin biological layers consisting of cells and their insoluble extracellular polymer, layers known as biofilms. Current toxic wastewater or wastegas treatment reactors exploit bacterial biofilm systems for certain system operating advantages. Using recombinant bacteria within a biofilm reactor to degrade xenobiotic wastes requires finding a suitable host to harbor and express the desired plasmid phenotype. Suitable host characteristics include: the ability to produce copious amounts of biofilm, resistance to waste-related injury and toxicity, and the ability to retain and express the desired plasmid during long term operation. This paper reports on a laboratory evaluation of factors governing plasmid retention and the expression of trichloroethene (TCE) degradative capacity in both suspended and biofilm cultures.

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Restoration of cylinder liners for automotive tractors engines in modern conditions

Tekhnicheskiy servis mashin ◽

10.22314/2618-8287-2020-58-1-122-133 ◽

2020 ◽

pp. 122-133

Author(s):

Vyacheslav A. Denisov ◽

Aleksandr Yu. Kostyukov ◽

Roman N. Zadorozhniy

Keyword(s):

Adhesion Strength ◽

Electrode Materials ◽

Research Purpose ◽

Laboratory Studies ◽

Term Operation ◽

Operational Load ◽

Operational Tests ◽

Conducting Research ◽

Cylinder Liners

One of the most promising technologies for restoring machine parts and cylinder liners is electric spark treatment as the most versatile technology that provides high-quality restoration of worn parts with wear up to 0.5 mm. (Research purpose) The research purpose is in developing a technology for restoring various cylinder liners by means of electric spark processing, selecting optimal modes and electrode materials that allow improving the quality of repair and increasing the post-repair life of the sleeve. (Materials and methods) It was taken into account when conducting research aimed at restoring the geometric parameters of the sleeve, that the coating must have sufficient adhesion strength to the surface of the sleeve under mechanical, thermal loads and long-term operation. Laboratory studies of the adhesion strength of electric spark coatings on the separation (adhesive) and on the cut, as well as tribotechnical studies of interfaces were conducted. Authors have found by analyzing the results of operational tests of restored and new cylinder liners the prospects for using electric spark treatment of worn parts, including diesel engine liners. (Results and discussion) It was shown by laboratory studies of the adhesion strength of electric spark coatings with a 0.2 mm thick BrMKc 3-1 electrode to the working surface of cylinder liners that their separation strength (adhesive) was 20-40 megapascals, and the shear strength (cohesive) was 50-80 megapascals. It was found that this provides the required functional strength of coatings with maximum operational load. The article presents the results of comprehensive research in graphs and tables. (Conclusions) The research conducted in the CCP "Nano-Center" of the FSAC VIM and operational tests in the 2nd bus fleet of Moscow confirmed the principal possibility of effectively restoring cast iron liners (blocks) using the technology of electric spark processing.

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