Study on Dephosphorization Technologies in Converter with Semi-Steel

2011 ◽  
Vol 396-398 ◽  
pp. 1119-1125
Author(s):  
Jian Hua Zeng ◽  
Wei He ◽  
Yong Chen ◽  
Hong Pan

Because of disadvantages of converter steelmaking with semi-steel in Panzhihua Steel, such as slow-footed slag forming, low rate of dephosphorization, high rate of rephosphorization after converter smelting, studies on increasing dephosphorization rate have been carried out. These studies comprise the optimization of slagging process, oxygen supply, bottom argon supply, end-point control of converter smelting, and so on. With these countermeasures, the rate of dephosphorization has been increased obviously. The results show that the average rate of dephosphorization is above 90% with single-slag process during converter smelting. Otherwise, content of phosphorus at the end-point of converter smelting can be controlled below 0.007%, and rephosphorization rate after converter smelting can be controlled below 0.003%, which meets the requirement of [P]≤0.010% for steel products.

2013 ◽  
Vol 634-638 ◽  
pp. 3265-3270 ◽  
Author(s):  
Zhi Peng He ◽  
Hua Zhang ◽  
Yan Hong Wang

The end point control for converter steelmaking is important operation in converter smelting later stage, and the end point control level directly affects the production efficiency and product quality. From the point of view of auxiliary resources operating characteristics, we analyzed the steelmaking end point control process, established the terminal forecast model based on DRNN type neural network, and established terminal optimization control model using improved particle swarm optimization algorithm to solve, and finally drew converter terminal optimization control strategy. Through the simulation, the optimal results show that: When the end forecast error (ω[△C]<±0.03%), hit rate is 93.1%, and with (ω[△T]<±12°C), hit rate is 94%, supplementary blowing oxygen time is 2.3 min, and materials resources saving 15%. For promoting the work of energy saving and emission reduction of Converter steelmaking process, it has important practical significance.


1980 ◽  
Vol 8 (1) ◽  
pp. 10-12
Author(s):  
F. C. Brenner

Abstract Tread wear rates during first wear measured by groove depth and weight changes do not always agree. Sometimes, the groove depth method shows a high rate and the weight loss method a low rate. Reported here are experiments designed to determine if grooves show depth changes without wear. Four tires were measured before mounting on a wheel, after mounting and inflation, and after inflation and storage. The mounted and inflated tires showed shallower shoulder grooves and deeper center grooves than the unmounted tires. In a second experiment, tires were measured immediately after a tread wear test and then stored mounted for two weeks before remeasuring. Each groove became deeper, and there was no change in the crown radius of any tire.


Genetics ◽  
2004 ◽  
Vol 166 (2) ◽  
pp. 797-806 ◽  
Author(s):  
James D Fry

Abstract High rates of deleterious mutations could severely reduce the fitness of populations, even endangering their persistence; these effects would be mitigated if mutations synergize each others’ effects. An experiment by Mukai in the 1960s gave evidence that in Drosophila melanogaster, viability-depressing mutations occur at the surprisingly high rate of around one per zygote and that the mutations interact synergistically. A later experiment by Ohnishi seemed to support the high mutation rate, but gave no evidence for synergistic epistasis. Both of these studies, however, were flawed by the lack of suitable controls for assessing viability declines of the mutation-accumulation (MA) lines. By comparing homozygous viability of the MA lines to simultaneously estimated heterozygous viability and using estimates of the dominance of mutations in the experiments, I estimate the viability declines relative to an appropriate control. This approach yields two unexpected conclusions. First, in Ohnishi’s experiment as well as in Mukai’s, MA lines showed faster-than-linear declines in viability, indicative of synergistic epistasis. Second, while Mukai’s estimate of the genomic mutation rate is supported, that from Ohnishi’s experiment is an order of magnitude lower. The different results of the experiments most likely resulted from differences in the starting genotypes; even within Mukai’s experiment, a subset of MA lines, which I argue probably resulted from a contamination event, showed much slower viability declines than did the majority of lines. Because different genotypes may show very different mutational behavior, only studies using many founding genotypes can determine the average rate and distribution of effects of mutations relevant to natural populations.


2021 ◽  
Vol 11 (10) ◽  
pp. 4630
Author(s):  
Alessandro Bonforte ◽  
Flavio Cannavò ◽  
Salvatore Gambino ◽  
Francesco Guglielmino

We propose a multi-temporal-scale analysis of ground deformation data using both high-rate tilt and GNSS measurements and the DInSAR and daily GNSS solutions in order to investigate a sequence of four paroxysmal episodes of the Voragine crater occurring in December 2015 at Mt. Etna (Italy). The analysis aimed at inferring the magma sources feeding a sequence of very violent eruptions, in order to understand the dynamics and to image the shallow feeding system of the volcano that enabled such a rapid magma accumulation and discharge. The high-rate data allowed us to constrain the sources responsible for the fast and violent dynamics of each paroxysm, while the cumulated deformation measured by DInSAR and daily GNSS solutions, over a period of 12 days encompassing the entire eruptive sequence, also showed the deeper part of the source involved in the considered period, where magma was stored. We defined the dynamics and rates of the magma transfer, with a middle-depth storage of gas-rich magma that charges, more or less continuously, a shallower level where magma stops temporarily, accumulating pressure due to the gas exsolution. This machine-gun-like mechanism could represent a general conceptual model for similar events at Etna and at all volcanoes.


1994 ◽  
Vol 30 (4) ◽  
pp. 211-214 ◽  
Author(s):  
E. Brands ◽  
M. Liebeskind ◽  
M. Dohmann

This study shows a comparison of important parameters for dynamic simulation concerning the highrate and low-rate activated sludge tanks of several municipal wastewater treatment plants. The parameters for the dynamic simulation of the single-stage process are quite well known, but parameters for the high-ratellow-rate activated sludge process are still missi ng, although a considerable number of wastewater treatment plants are designed and operated that way. At present any attempt to simulate their operation is restricted to the second stage due to missing data concerning growth rate, decay rate, yield coefficient and others.


1993 ◽  
Vol 28 (7) ◽  
pp. 243-250 ◽  
Author(s):  
Y. Suzuki ◽  
S. Miyahara ◽  
K. Takeishi

Gas-permeable film can separate air and water, and at the same time, let oxygen diffuse from the air to the water through the film. An oxygen supply method using this film was investigated for the purpose of reducing energy consumption for wastewater treatment. The oxygen transfer rate was measured for the cases with or without biofilm, which proved the high rate of oxygen transfer in the case with nitrifying biofilm which performed nitrification. When the Gas-permeable film with nitrifying biofilm was applied to the treatment of wastewater, denitrifying biofilm formed on the nitrifying biofilm, and simultaneous nitrification and denitrification occurred, resulting in the high rate of organic matter and T-N removal (7 gTOC/m2/d and 4 gT-N/m2/d, respectively). However, periodic sloughing of the denitrifying biofilm was needed to keep the oxygen transfer rate high. Energy consumption of the process using the film in the form of tubes was estimated to be less than 40% of that of the activated sludge process.


2006 ◽  
Vol 290 (3) ◽  
pp. F600-F605 ◽  
Author(s):  
Rajiv Agarwal

Patients with diabetic nephropathy have a high rate of cardiovascular events and mortality. Nontraditional cardiovascular risk factors such as oxidative stress and inflammation are thought to be particularly important in mediating these events. Studies suggest that thiazolidinediones (TZDs) can reduce the level of nontraditional cardiovascular risk in people with or without diabetes mellitus. Whether this benefit occurs in patients with diabetic nephropathy is unknown. I hypothesized that the TZD pioglitazone will mitigate oxidative stress and inflammation compared with glipizide in patients with overt diabetic nephropathy. Markers of oxidative stress (plasma and urine albumin carbonyl and total protein carbonyls and malondialdehyde), inflammation [white blood cell (WBC) count, C-reactive protein (CRP), plasma IL-6, TNF-α], and plaque stability [matrix metalloproteinase 9 (MMP-9)] were measured in frozen samples obtained from patients with overt diabetic nephropathy participating in a randomized, open-label, blinded end-point, 16-wk trial with glipizide ( n = 22) or pioglitazone ( n = 22). Pioglitazone therapy in men with advanced diabetic nephropathy reduced WBC count by 1,125/μl ( P < 0.001), CRP by 41% ( P = 0.042), IL-6 by 38% ( P = 0.009), and MMP-9 by 29% ( P = 0.016). Specific differential reductions in WBC count of 1,251/μl ( P = 0.009) and reduction in IL-6 of 58% with pioglitazone ( P = 0.001) were seen compared with glipizide. There were no statistically significant changes observed with plasma TNF-α concentrations or markers of oxidative stress with either hypoglycemic agent. In conclusion, pioglitazone reduces proinflammatory markers in patients with overt diabetic nephropathy, which indicates potentially beneficial effects on overall cardiovascular risk. This surrogate end point needs to be confirmed in trials designed to demonstrate cardiovascular protection.


1971 ◽  
Vol 29 (3_suppl) ◽  
pp. 1196-1198 ◽  
Author(s):  
Richard S. Calef ◽  
Richard A. Kaufman ◽  
Ronald N. Bone ◽  
Steven A. Werk

The present experiment investigated the effects of noncontingent nonreinforcement as the aversive event in a CER paradigm. The results showed a significant response-facilitation effect during early training, but none during later training with a high rate-producing, high-density reinforcement schedule. The present results imply that a low rate-producing, high-density reinforcement schedule is not a necessary condition for response facilitation.


1925 ◽  
Vol 8 (2) ◽  
pp. 21-31 ◽  
Author(s):  
G. H. Parker

1. Quiescent sciatic nerve of the frog discharges CO2 at the average rate of 0.00876 mg. CO2 per gram of nerve per minute. 2. Sciatic nerve steeped one minute in boiling water discharges CO2 at first at a low rate and after an hour and a half not at all. 3. Degenerated sciatic nerve discharges CO2 at a slightly higher rate than normal living nerve does. 4. Connective tissue from the frog discharges CO2 at an average rate of 0.0097 mg. per gram of tissue per minute. 5. Assuming that a nerve is composed of from one-half to one-quarter connective tissue the CO2 output from its strictly nervous components is estimated to be at a rate of 0.008 mg. CO2 per gram of nerve per minute. 6. Stimulated sciatic nerve increases the rate of its CO2 output over quiescent nerve by about 14 per cent. When this number is corrected for strictly nervous tissue the rate is about 16 per cent. 7. The increased rate of CO2 production noted on stimulation in normal sciatic nerves was not observed when they were boiled, blocked, or degenerated. It was also not observed with stimulated strands of connective tissue.


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