Calculation of principal characteristics of turbulent streams in a state of structural equilibrium

1975 ◽  
Vol 14 (1) ◽  
pp. 77-80
Author(s):  
G. E. Sturov
Keyword(s):  
Principal Characteristics ◽  
Structural Equilibrium

scholarly journals Influence of the Submerged Entry Nozzle’s Bottom Well on the Characteristics of Its Exit Jets

Metals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 398
Author(s):  
Jesus Gonzalez-Trejo ◽  
Cesar A. Real-Ramirez ◽  
Jose Raul Miranda-Tello ◽  
Ruslan Gabbasov ◽  
Ignacio Carvajal-Mariscal ◽  
...  
Keyword(s):  
Continuous Casting ◽  
Liquid Steel ◽  
Mold Wall ◽  
Casting Machine ◽  
Submerged Entry Nozzle ◽  
Central Plane ◽  
Impact Point ◽  
Single Vortex ◽  
Hydrodynamic Analysis ◽  
Principal Characteristics

In vertical continuous casting machines the liquid steel from the tundish is poured into the mold through the Submerged Entry Nozzle (SEN). The shape and direction of the SEN exit jets affect the liquid steel dynamics inside the mold. This work quantifies the effect of the SEN pool on the principal characteristics of the jets emerging from it, precisely, the shape, the spread angles, and the mold impact point. Experimental and numerical simulations were carried out using a SEN simplified model, a square-shaped bore nozzle with square-shaped outlet ports whose length is minimal. These experiments showed two well-defined behaviors. When a single vortex dominates the hydrodynamics inside the simplified SEN, the exit jets spread out and are misaligned about the mold’s central plane. On the contrary, when the inner flow pattern shows two vortexes, the exit jets are compact and parallel to the mold wide walls. The measured difference on the jet’s falling angles is 5°, approximately, which implies that in an actual casting machine, the impingement point at the narrow mold wall would have a variation of 0.150 m. This hydrodynamic analysis would help design new SENs for continuous casting machines that improve steel quality.

Aging of iron manganite negative temperature coefficient thermistors

1998 ◽  
Vol 13 (5) ◽  
pp. 1238-1242 ◽  
Author(s):  
T. Battault ◽  
R. Legros ◽  
A. Rousset
Keyword(s):  
Temperature Coefficient ◽  
Spinel Structure ◽  
Negative Temperature Coefficient ◽  
Negative Temperature ◽  
X Ray Diffraction ◽  
X Ray ◽  
Octahedral Sites ◽  
Before And After ◽  
Structural Equilibrium ◽  
Electrical Data

“Aging,” defined as the drift of resistance with temperature after 1000 h, was investigated for iron manganite temperature coefficient thermistors. For these devices, aging is relatively large, about 10%. The cationic distributions before and after aging were determined by Mössbauer spectroscopy. These distributions explain all the x-ray diffraction and correlated electrical data. The origin of the aging observed on iron manganites thermistors has been identified. It is due to the migration of Fe3+ ions from tetrahedral to octahedral sites of the spinel structure in order to reach a structural equilibrium.

scholarly journals Oscillating foils of high propulsive efficiency

1998 ◽  
Vol 360 ◽  
pp. 41-72 ◽  
Author(s):  
J. M. ANDERSON ◽  
K. STREITLIEN ◽  
D. S. BARRETT ◽  
M. S. TRIANTAFYLLOU
Keyword(s):  
Reynolds Number ◽  
High Efficiency ◽  
Leading Edge ◽  
Half Cycle ◽  
Trailing Edge ◽  
Propulsive Efficiency ◽  
Principal Characteristics ◽  
Theoretical Predictions ◽  
Power Measurements ◽  
Oscillating Foils

Thrust-producing harmonically oscillating foils are studied through force and power measurements, as well as visualization data, to classify the principal characteristics of the flow around and in the wake of the foil. Visualization data are obtained using digital particle image velocimetry at Reynolds number 1100, and force and power data are measured at Reynolds number 40 000. The experimental results are compared with theoretical predictions of linear and nonlinear inviscid theory and it is found that agreement between theory and experiment is good over a certain parametric range, when the wake consists of an array of alternating vortices and either very weak or no leading-edge vortices form. High propulsive efficiency, as high as 87%, is measured experimentally under conditions of optimal wake formation. Visualization results elucidate the basic mechanisms involved and show that conditions of high efficiency are associated with the formation on alternating sides of the foil of a moderately strong leading-edge vortex per half-cycle, which is convected downstream and interacts with trailing-edge vorticity, resulting eventually in the formation of a reverse Kármán street. The phase angle between transverse oscillation and angular motion is the critical parameter affecting the interaction of leading-edge and trailing-edge vorticity, as well as the efficiency of propulsion.

Breast Cancer in Childhood

1968 ◽  
Vol 54 (5) ◽  
pp. 369-377 ◽  
Author(s):  
Umberto Veronesi ◽  
Lorenzo Zingo ◽  
Bruno Salvadori
Keyword(s):  
Breast Cancer ◽  
Surgical Procedure ◽  
Radical Mastectomy ◽  
Principal Characteristics ◽  
Simple Mastectomy ◽  
Cancer In Children

A case of breast cancer in a 8-year old girl is described, and 23 cases of breast cancer in children previously reported in the literature are analysed. The principal characteristics of breast cancer in children, unlike breast cancer in adults, seem to be a better prognosis, not depending on the surgical procedure (excision, simple mastectomy or radical mastectomy) and the frequent secretive appearance of the neoplasm, always of ductal origin.

Investigation of principal characteristics of a laser projection microscope

1976 ◽  
Vol 6 (1) ◽  
pp. 17-22 ◽  
Author(s):  
K I Zemskov ◽  
A A Isaev ◽  
M A Kazaryan ◽  
G G Petrash
Keyword(s):  
Principal Characteristics
Sign in / Sign up

Export Citation Format

Share Document