Natural stabilization and disruption of damped turbulent diffusion of a gas flame

1991 ◽  
Vol 27 (5) ◽  
pp. 584-588 ◽  
Author(s):  
G. E. Golinevich ◽  
V. L. Karpov ◽  
A. P. Fedotov ◽  
I. A. Bolod'yan ◽  
V. I. Makeev ◽  
...  
Keyword(s):  
Turbulent Diffusion ◽  
Natural Stabilization ◽  
Gas Flame

Re-Embedding of Specimens for Maximum Orientation

1972 ◽  
Vol 30 ◽  
pp. 696-697 ◽  
Author(s):  
Margot Brundage ◽  
Robert F. Dunn
Keyword(s):  
Tissue Block ◽  
Gas Flame

Re-embedding of plastic impregnated tissue blocks is easily accomplished when a combination of carnuba and Tenax dental waxes is used. This method is particularly helpful when combined with capsule flat end embedding, because the entire orientation range of the microtome can be utilized for final exact positioning of the specimen. A demonstration of both techniques will be given.The advantages of re-embedding are: 1, complete freedom in orientation of the tissue, and 2, multiple segments of the same block can be used for various orientations. Re-embedding involves: 1, removal of a tissue block from the surrounding plastic (Fig. 1), and 2, orientation and embedding of the tissue into wax which has suitable support properties for sectioning.Equipment and materials needed for re-embedding include: dissecting microscope; wax mixture ( carnuba 35%, Tenax 65%); empty gelatine capsules; dental carvers; dissecting needles; #7 Dupont forceps; Pasteur pipettes; specimen holders; razor blades; and gas flame.

The Calculation of Turbulent Diffusion Coefficients in Aquatic Ecosystems

2019 ◽  
Vol 70 (11) ◽  
pp. 3903-3907
Author(s):  
Galina Marusic ◽  
Valeriu Panaitescu
Keyword(s):  
Transport Equation ◽  
Turbulent Diffusion ◽  
Diffusion Coefficients ◽  
Aquatic Ecosystems ◽  
Specific Area ◽  
Left Bank ◽  
The Right ◽  
Prut River

The paper deals with the issues related to the pollution of aquatic ecosystems. The influence of turbulence on the transport and dispersion of pollutants in the mentioned systems, as well as the calculation of the turbulent diffusion coefficients are studied. A case study on the determination of turbulent diffusion coefficients for some sectors of the Prut River is presented. A new method is proposed for the determination of the turbulent diffusion coefficients in the pollutant transport equation for specific sectors of a river, according to the associated number of P�clet, calculated for each specific area: the left bank, the right bank and the middle of the river.

Investigation of pre-sprayed powders for electric contact welding

2020 ◽  
pp. 143-149
Author(s):  
Dinar R. Masalimov ◽  
Roman R. Galiullin ◽  
Rinat N. Sayfullin ◽  
Azamat F. Fayurshin ◽  
Linar F. Islamov
Keyword(s):  
Adhesion Strength ◽  
Electrical Contact ◽  
Research Purpose ◽  
Flame Spraying ◽  
Powder Materials ◽  
Electric Contact ◽  
Metal Powders ◽  
Unstable Flow ◽  
Gas Flame ◽  
Contact Welding

There are a number of difficulties in the electrical contact welding of powder materials: shedding of powder from the surface of a cylindrical part, impossibility of hardening the layer during welding due to flushing of the powders with coolant and unstable flow of powder into the welding zone. One solution is pre-spraying the powder in some way. (Research purpose). The research purpose is investigating the possibility of electric contact welding of metal powders preliminarily sprayed by a gas-flame method, namely, adhesion strength and losses during preliminary gas-flame spraying of powders. (Materials and methods) Powders of grades PG-NA-01, PrKhIIG4SR, PRZh3.200.28 were sprayed onto flat samples of St3 steel, polished to a roughness of Ra 1.25. The strength of powder adhesion to the base was studied by the cut method. (Results and discussion) The percentage loss of the powder as a whole is 3-23 percent for all the distances studied. The greatest powder losses appear at a distance of more than 180 millimeter from the tip of the burner for powders of grades PG-NA-01 and PrKhIIG4SR. The smallest powder losses were observed for PrZh3.200.28 powder, which totaled 3-7 percent. The maximum adhesion strength of the sprayed powders to the surface was 22.1 megapascals' when spraying the PG-NA-01 powder. The adhesion strength of powders of the grades PrKhIIG4SR and PrZh3.200.28 is small and amounts to 0.2-3 megapascals'. (Conclusions) The use of preliminary flame spraying of powders for their further electric contact welding is possible using PG-NA-01 grade powder, while the best adhesion to the base (that is more than 20 megapascals') is achieved with a spraying distance of 120-140 millimeter. The smallest powder losses during flame spraying are achieved at a spraying distance of 100-160 centimeters', at which the powder loss for the studied grades was 4-12 percent.

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