scholarly journals The investigation on the middle period dephosphorization in 70t converter

2020 ◽  
Vol 39 (1) ◽  
pp. 567-575
Author(s):  
Deng Nanyang ◽  
Wang Haijun ◽  
Ling Haitao ◽  
Wang Jianjun

AbstractAn experimental test is carried out on the 70t converter in Masteel to study the law of middle period dephosphorization in the smelting period. It is found that the dephosphorization rate is slow in the early and middle period of smelting and the content of the final P in steel cannot reach the standard due to the low oxidation of slag. The content of the final P in steel can be controlled within 0.02% by adding ore to the molten bath in the middle period and raising the lance position. The experimental test shows that the dephosphorization can still be achieved by a large margin if appropriate slag conditions are maintained in the middle period when the C and O reactions are strong. By theoretical calculation, it is concluded that the slag content should be controlled between 15 and 23%, and the basicity of slag should be between 2.5 and 2.8 in the middle period of production. Through the observation of experimental slag by SEM, it is found that the limiting factor of dephosphorization in the middle period under the test conditions is that the dephosphorization speed is too slow due to the low oxidation, rather than the solidification of phosphorus.

2021 ◽  
pp. 108438
Author(s):  
Daniel LaBrier ◽  
Ben Lilley ◽  
Anton Higgins ◽  
Ryan Stewart ◽  
Todd Palmer ◽  
...  

Author(s):  
E. Grant Jones ◽  
Walter J. Balster ◽  
James M. Pickard

Surface fouling in aircraft fuel lines that results from autoxidation of aviation fuel remains a serious and very complicated problem. This area has been studied using two Jet-A fuels, POSF-2827 and POSF-2980. The results of a series of dynamic experiments conducted in a single-pass, tubular heat exchanger operated at very slow flow rates under near-isothermal conditions are reported herein. Such studies, by minimizing complications resulting from fluid dynamics and heat flow, constitute a simpler global approach to the chemistry of fouling. The basis for the selection of experimental test conditions is discussed, and data from measurements of dissolved oxygen and surface deposition as a function of fuel stress duration are presented. The effects of parameters such as reaction temperature, tube diameter, experimental test time, and fuel dopants are considered.


1996 ◽  
Vol 118 (2) ◽  
pp. 286-291 ◽  
Author(s):  
E. G. Jones ◽  
W. J. Balster ◽  
J. M. Pickard

Surface fouling in aircraft fuel lines that results from autoxidation of aviation fuel remains a serious and very complicated problem. This area has been studied using two Jet-A fuels, POSF-2827 and POSF-2980. The results of a series of dynamic experiments conducted in a single-pass, tubular heat exchanger operated at very slow flow rates under near-isothermal conditions are reported herein. Such studies, by minimizing complications resulting from fluid dynamics and heat flow, constitute a simpler global approach to the chemistry of fouling. The basis for the selection of experimental test conditions is discussed, and data from measurements of dissolved oxygen and surface deposition as a function of fuel stress duration are presented. The effects of parameters such as reaction temperature, tube diameter, experimental test time, and fuel dopants are considered.


2012 ◽  
Vol 34 (1) ◽  
pp. 35-66 ◽  
Author(s):  
Gerald P. Berent ◽  
Ronald R. Kelly ◽  
Tanya Schueler-Choukairi

This study assessed knowledge of numerically quantified English sentences in two learner populations—second language (L2) learners and deaf learners—whose acquisition of English occurs under conditions of restricted access to the target language input. Under the experimental test conditions, interlanguage parallels were predicted to arise from acquisitional pressures imposed by derivational economy on universal grammar (UG)–guided semantic interpretation. The results of a task in which participants matched sentences to multiple discourse depictions confirmed the predicted parallels. However, in matching underinformative sentences to depicted contexts, the L2 and deaf learner groups overactivated discourse-pragmatic knowledge. The restriction of indefinite noun phrases to singleton indefinites and the cancellation of scalar implicatures rendered sentences more informative in underinformative contexts, producing incorrect—although principled—interpretations. These results inform English acquisition at the interface of semantics and discourse pragmatics and provide further support that economy pressures yield L2 learner and deaf learner interlanguage parallels as observed, for instance, in learners’ interpretative knowledge of universally quantified English sentences.


2020 ◽  
Vol 5 (1) ◽  
pp. 79-86
Author(s):  
Liudmila Liutsko ◽  
Jose Maria Tous ◽  
Sergi Segura

The aim of the given preliminary study was to check whether any changes in fi ne motor behaviour exist in switching from single to double task (with cognition charge) in proprioceptive sensory graphomotor test conditions. Ten students (fi ve males and fi ve females), aged from 20 to 30 years old, took part in the experiment - precision of tracking of the models in both experimental test conditions: without and with cognitive task (counting numbers back). The variables for assessment were obtained with use of the digitalized proprioceptive diagnostics (Tous, 2008; Tous, J.M., Muiños, Tous, O., & Tous J, 2012) of Mira y Lopez laboratory (University of Barcelona) that transformed the measurements of drawn lines on a touch screen from pixels into millimetres. As results showed, in the proprioceptive test condition, the changes in deviations related to spatial (lineograms) or line length variability (parallels) did not reach any statistical signifi cance; while the changes in line length performance (lineograms) were found signifi cant (that corresponds to inhibition- -excitatory balance of nervous system).


Author(s):  
J. N. Meador ◽  
C. N. Sun ◽  
H. J. White

The electron microscope is being utilized more and more in clinical laboratories for pathologic diagnosis. One of the major problems in the utilization of the electron microscope for diagnostic purposes is the time element involved. Recent experimentation with rapid embedding has shown that this long phase of the process can be greatly shortened. In rush cases the making of projection slides can be eliminated by taking dark field electron micrographs which show up as a positive ready for use. The major limiting factor for use of dark field micrographs is resolution. However, for conference purposes electron micrographs are usually taken at 2.500X to 8.000X. At these low magnifications the resolution obtained is quite acceptable.


Author(s):  
Zhifeng Shao

Recently, low voltage (≤5kV) scanning electron microscopes have become popular because of their unprecedented advantages, such as minimized charging effects and smaller specimen damage, etc. Perhaps the most important advantage of LVSEM is that they may be able to provide ultrahigh resolution since the interaction volume decreases when electron energy is reduced. It is obvious that no matter how low the operating voltage is, the resolution is always poorer than the probe radius. To achieve 10Å resolution at 5kV (including non-local effects), we would require a probe radius of 5∽6 Å. At low voltages, we can no longer ignore the effects of chromatic aberration because of the increased ratio δV/V. The 3rd order spherical aberration is another major limiting factor. The optimized aperture should be calculated as


Author(s):  
P. Pradère ◽  
J.F. Revol ◽  
R. St. John Manley

Although radiation damage is the limiting factor in HREM of polymers, new techniques based on low dose imaging at low magnification have permitted lattice images to be obtained from very radiation sensitive polymers such as polyethylene (PE). This paper describes the computer averaging of P4MP1 lattice images. P4MP1 is even more sensitive than PE (total end point dose of 27 C m-2 as compared to 100 C m-2 for PE at 120 kV). It does, however, have the advantage of forming flat crystals from dilute solution and no change in d-spacings is observed during irradiation.Crystals of P4MP1 were grown at 60°C in xylene (polymer concentration 0.05%). Electron microscopy was performed with a Philips EM 400 T microscope equipped with a Low Dose Unit and operated at 120 kV. Imaging conditions were the same as already described elsewhere. Enlarged micrographs were digitized and processed with the Spider image processing system.


Author(s):  
S.K. Aggarwal ◽  
J.M. Fadool

Cisplatin (CDDP) a potent antitumor agent suffers from severe toxic side effects with nephrotoxicity being the major dose-limiting factor, The primary mechanism of its action has been proposed to be through its cross-linking DNA strands. It has also been shown to inactivate various transport enzymes and induce hypocalcemia and hypomagnesemia that may be the underlying cause for some of its toxicities. The present is an effort to study its influence on the parathyroid gland for any hormonal changes that control calcium levels in the body.Male Swiss Wistar rats (Crl: (WI) BR) weighing 200-300 g and of 60 days in age were injected (ip) with cisplatin (7mg/kg in normal saline). The controls received saline injections only. The animals were injected (iv) with calcium (0.5 ml of 10% calcium gluconate/day) and were killed by decapitation on day 1 through 5. Trunk blood was collected in heparinized tubes.


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