scholarly journals Development of welded structure of 5-nozzle lance heads in converter shop of PJSC “Dneprovsky metallurgical combine”

2020 ◽  
Vol 63 (10) ◽  
pp. 815-822
Author(s):  
S. P. Panteikov
Keyword(s):  
High Temperature ◽  
Outer Surface ◽  
Converter Shop ◽  
Mechanical Stresses ◽  
Complete Elimination ◽  
Welded Structures ◽  
Average Resistance ◽  
Welded Structure ◽  
Inner Surface ◽  
Metallurgical Combine

For the upper blasting lances of 250-tons oxygen converters at PJSC «DMС» (Kamenskoe, Ukraine) the author has proposed a number of welded structures of 5-nozzle lance heads with increased resistance. A set of industrial studies of their operation made it possible to establish that the devices which provide cooling of the areas back from the nozzle zone of the tip have the highest resistance. Measures to increase the values of the average cooler speeds in welded structures of the lance heads and their rigidity also turned out to be quite effective. The transfer of copper welds holding the nozzle inserts in the copper tip from its outer surface to the inner proved to be ineffective from the point of increasing resistance of the lance head (the average resistance of the heads increased by only 7 heats – from 78 to 85 heats). This allows us to assert the need for complete elimination of copper welds in the head (both external, exposed to high-temperature and mechanical stresses, and internal) that hold nozzle inserts in the holes of the welded tip and lance head collector. Thus, in spite of all the measures taken to transfer the welds from the outer surface of the tip to its inner surface, to improve cooling of the tip and its back from the nozzle zones, which also include sections of copper welds around the nozzles, as well as to increase the rigidity of the blast welded structure heads, this led, although to positive, but still to relatively low results. The data obtained indicate that welds made of copper around the nozzle inserts, which are held by this in the tip (also in the collector) of the head, are the limiting link that does not significantly increase the resistance of welded lance heads, and it is urgently necessary to back off its use. 

A SEM and Light Microscope Study of the Epidermal Leaf Structures of the Carnivorous Plant, Sarracenia purpurea, L.

1971 ◽  
Vol 29 ◽  
pp. 358-359
Author(s):  
B. J. Panessa ◽  
J. F. Gennaro
Keyword(s):  
Methylene Blue ◽  
Toluidine Blue ◽  
Outer Surface ◽  
Microscope Study ◽  
Light Microscope ◽  
Carnivorous Plant ◽  
Sarracenia Purpurea ◽  
Inner Surface

Tissue from the hood and sarcophagus regions were fixed in 6% glutaraldehyde in 1 M.cacodylate buffer and washed in buffer. Tissue for SEM was partially dried, attached to aluminium targets with silver conducting paint, carbon-gold coated(100-500Å), and examined in a Kent Cambridge Stereoscan S4. Tissue for the light microscope was post fixed in 1% aqueous OsO4, dehydrated in acetone (4°C), embedded in Epon 812 and sectioned at ½u on a Sorvall MT 2 ultramicrotome. Cross and longitudinal sections were cut and stained with PAS, 0.5% toluidine blue and 1% azure II-methylene blue. Measurements were made from both SEM and Light micrographs.The tissue had two structurally distinct surfaces, an outer surface with small (225-500 µ) pubescent hairs (12/mm2), numerous stoma (77/mm2), and nectar glands(8/mm2); and an inner surface with large (784-1000 µ)stiff hairs(4/mm2), fewer stoma (46/mm2) and larger, more complex glands(16/mm2), presumably of a digestive nature.

Ultrastructure and development of urediospore ornamentation in Melampsora lini

1971 ◽  
Vol 49 (12) ◽  
pp. 2067-2073 ◽  
Author(s):  
L. J. Littlefield ◽  
C. E. Bracker
Keyword(s):  
Endoplasmic Reticulum ◽  
Plasma Membrane ◽  
Outer Surface ◽  
Spore Wall ◽  
Wall Material ◽  
Wild Type ◽  
Melampsora Lini ◽  
Inner Surface ◽  
External Position ◽  
Basal Portion

The urediospores of Melampsora lini (Ehrenb.) Lev. are echinulate, with spines ca. 1 μ long over their surface. The spines are electron-transparent, conical projections, with their basal portion embedded in the electron-dense spore wall. The entire spore, including the spines, is covered by a wrinkled pellicle ca. 150–200 Å thick. The spore wall consists of three recognizable layers in addition to the pellicle. Spines form initially as small deposits at the inner surface of the spore wall adjacent to the plasma membrane. Endoplasmic reticulum occurs close to the plasma membrane in localized areas near the base of spines. During development, the spore wall thickens, and the spines increase in size. Centripetal growth of the wall encases the spines in the wall material. The spines progressively assume a more external position in the spore wall and finally reside at the outer surface of the wall. A mutant strain with finely verrucose spores was compared to the wild type. The warts on the surface of the mutant spores are rounded, electron-dense structures ca. 0.2–0.4 μ high, in contrast to spines of the wild type. Their initiation near the inner surface of the spore wall and their eventual placement on the outer surface of the spore are similar to that of spines. The wall is thinner in mutant spores than in wild-type spores.

Development of Inverse Analysis of Heat Conduction and Thermal Stress for Elbow: Part I

2013 ◽  
Author(s):  
Seiji Ioka ◽  
Shiro Kubo ◽  
Mayumi Ochi ◽  
Kiminobu Hojo
Keyword(s):  
Heat Conduction ◽  
Thermal Stress ◽  
Transfer Function ◽  
Surface Temperature ◽  
Outer Surface ◽  
Inverse Analysis ◽  
Temperature History ◽  
Analysis Method ◽  
Inner Surface ◽  
Inverse Analysis Method

Thermal fatigue may develop in piping elbow with high temperature stratified flow. To prevent the fatigue damage by stratified flow, it is important to know the distribution of thermal stress and temperature history in a pipe. In this study, heat conduction inverse analysis method for piping elbow was developed to estimate the temperature history and thermal stress distribution on the inner surface from the outer surface temperature history. In the inverse analysis method, the inner surface temperature was estimated by using the transfer function database which interrelates the inner surface temperature with the outer surface temperature. Transfer function database was calculated by FE analysis in advance. For some patterns of the temperature history, inverse analysis simulations were made. It was found that the inner surface temperature history was estimated with high accuracy.

Expansion of the area vasculosa of the chick after removal of the ectoderm

Development ◽  
1970 ◽  
Vol 24 (1) ◽  
pp. 95-108
Author(s):  
J. M. Augustine
Keyword(s):  
Basement Membrane ◽  
Outer Surface ◽  
Chicken Embryo ◽  
Area Vasculosa ◽  
Inner Surface

The role of the ectoderm in the expansion of the mesoderm in the area vasculosa of the chicken embryo was studied. The basement membrane of the ectoderm was found to constitute a substratum for the expansion of both layers of mesoderm, since (a) the somatic mesoderm, particularly at its margin, adheres to the basement membrane, and (b) the somatic and splanchnic mesoderm adhere to each other throughout most of the area opaca. Following removal of the ectoderm from the outer surface of the basement membrane, movement of the underlying mesoderm along its inner surface stopped. Mean expansion of the mesoderm in these cases was zero. Following removal of both ectoderm and basement membrane, expansion of the underlying mesoderm was normal in amount. Experimental changes in the ectodermal substratum can thus stop movement of the associated mesoderm, but the role which the substratum normally plays in mesodermal expansion remains unclear.

Parametric Study of Dry Sliding Wear Behaviour of Functionally Graded Al LM25/Si3N4 Composite by Response Surface Methodology

2015 ◽  
Vol 24 (6) ◽  
pp. 096369351502400 ◽  
Author(s):  
N. Radhika ◽  
R. Raghu
Keyword(s):  
Response Surface Methodology ◽  
Wear Rate ◽  
Response Surface ◽  
Outer Surface ◽  
Sliding Wear ◽  
Centrifugal Casting ◽  
Functionally Graded ◽  
Wear Behaviour ◽  
Inner Surface ◽  
Sliding Distance

Functionally graded aluminium LM25/silicon nitride composite was produced through stir casting followed by centrifugal casting and obtained a hollow cylindrical cast component with dimensions of 150 × 150 × 20 mm. The microstructural examination and the hardness test were carried out on the outer (1 mm) and inner surface (17 mm) as the function of radial distance from the outer periphery. The outer surface was observed with particle enriched region compared to inner surface and exhibited higher hardness. Hence the outer surface of the functionally graded composite was only further subjected to sliding wear test in pin-on-disc tribometer. The Central Composite Design in Response Surface Methodology was used to design the experiments for the selected parameters such as load (15–45 N), velocity (0.5–2.5 m/s) and sliding distance (500–2000 m). Regression test and Analysis of Variance were conducted to check the adequacy of the constructed model. The surface plots for wear rate showed that wear rate increased with increase in load and non-linearly varied with increase in velocity and sliding distance. Scanning Electron Microscopy analysis was conducted on the worn-out surfaces and observed mild to severe wear transition on increase of load.

Measurement of Weld Mechanical Properties Using an Instrumented Indentation Technique

2017 ◽  
Vol 754 ◽  
pp. 383-386
Author(s):  
Kee Nam Song
Keyword(s):  
Mechanical Properties ◽  
Heat Affected Zone ◽  
Weld Zone ◽  
Base Material ◽  
Metal Structure ◽  
Instrumented Indentation ◽  
Welded Structures ◽  
Indentation Technique ◽  
Lower Confidence ◽  
Welded Structure

Different microstructures in the weld zone of a metal structure including a fusion zone and a heat affected zone, are formed as compared to the base material. Consequently, the mechanical properties in the weld zone are different from those in the base material to a certain degree owing to different microstructures and residual welding stresses. When a welded structure is loaded, the mechanical behavior of the welded structure might be different from the case of a structure with homogeneous mechanical properties. It is known that obtaining the mechanical properties in the weld is generally difficult owing to the narrow regions of the weld and interfaces. As an alternative way to obtain the weld mechanical properties, the weld mechanical properties of Alloy800HT, SUS316L, and Alloy617, were recently measured using an instrumented indentation technique, and the representative weld mechanical properties of these materials were estimated with a 95% lower confidence level for later structural analyses of the welded structures.

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