| 1. |
- Basu, Somnath, 1975-
(författare)
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Studies on dephosphorisation during steelmaking
- 2007
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This work is aimed at understanding the thermodynamic principles influencing the phosphorus partition between slag and steel during steelmaking, particularly during refining of high-phosphorus hot metal using the basic oxygen steelmaking (BOS) process. Mapping of the slag path has been carried out using a mass balance model based on input conditions and off-gas analysis, which has been validated by intermediate measurements of slag and metal composition in an industrial basic oxygen furnace (BOF). The slag composition is found to vary over a wide range of basicity (%CaO/%SiO2) and iron oxide content. The partition of phosphorus increases with progress of refining but reduces during the intermediate period, corresponding to a decrease in iron oxide concentration and formation of “dry slag”. The phosphorus partition ratio increases again towards the end of the process. The equilibrium partition ratios for such conditions have been theoretically estimated using slag “model(s)”, based on the estimated slag compositions. It is seen that the partition ratio of phosphorus remains within 45% – 60% of the equilibrium value, showing a gradual decrease with progress of the refining process. Equilibrium phosphorus partition ratios for slags containing low concentrations of MnO and Al2O3 have been experimentally determined, over the ranges of basicity and iron oxide concentration approximately corresponding to that observed in the typical BOS process. It is seen that the equilibrium phosphorus partition ratio is practically independent of basicity greater than 2.5 – 2.6, over the entire range of temperature and FeOx concentration studied. Variation of the activity of P2O5 with basicity and FeOx concentration has been investigated to explain the trends observed in the variation of phosphorus partition ratio. It is seen that the activity coefficient of P2O5 is lowest, and hence most conducive for removal of phosphorus from steel, over certain finite ranges of basicity and iron oxide concentration. It follows that the efficiency of dephosphorisation is likely to be maximum if the basic oxygen steelmaking process is operated within these ranges. Simultaneous with this work, mathematical correlations have been developed for estimation of P2O5 activity coefficient and phosphorus partition ratio as functions of slag composition. The correlations are compared with those proposed by earlier workers and are found to result in better predictions over certain composition ranges.
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| 2. |
- Hayashi, Miyuki, et al.
(författare)
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Evaluation of thermodynamic activity of a metallic oxide in a ternary slag from the sulphide capacity of the slag
- 2004
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Ingår i: ISIJ International. - : Iron and Steel Institute of Japan. - 0915-1559 .- 1347-5460. ; 44:11, s. 1783-1786
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Tidskriftsartikel (refereegranskat)abstract
- The correlation between the activity of a metallic oxide in a ternary slag system and the sulphide capacity of the slag was investigated. The solubility of sulphur in the binary systems CaO-SiO2 and Al2O3-CaO along with its sulphide capacity of the Al2O3-CaO-SiO2 system respectively have been used to estimate the activities of CaO at the compositions of some Al2O3-CaO-SiO2 intermediate compounds. Estimation has been carried out assuming that the Gibbs free energy of fusion for the ternary composition is additive of those for pure substances. The estimated values of the activities are in good agreement with the measured values. This correlation is not only used to evaluate the activity but also, by comparing the estimated activities with the measured ones, it is possible to elucidate the applicability of Henry's law to the activity of a metallic sulphide and to determine the order in the affinity of a cation to sulphur between two metallic oxides in a slag.
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| 3. |
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| 4. |
- Nakano, Naoko, et al.
(författare)
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TMED10 Protein Interferes with Transforming Growth Factor (TGF)-beta Signaling by Disrupting TGF-beta Receptor Complex Formation
- 2017
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Ingår i: Journal of Biological Chemistry. - : AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC. - 0021-9258 .- 1083-351X. ; 292:10, s. 4099-4112
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Tidskriftsartikel (refereegranskat)abstract
- The intensity and duration of TGF-beta signaling determine the cellular biological response. How this is negatively regulated is not well understood. Here, we identified a novel negative regulator of TGF-beta signaling, transmembrane p24-trafficking protein 10 (TMED10). TMED10 disrupts the complex formation between TGF-beta type I (also termed ALK5) and type II receptors (T beta RII). Misexpression studies revealed that TMED10 attenuated TGF-beta-mediated signaling. A 20-amino acid-long region from Thr(91) to Glu(110) within the extracellular region of TMED10 was found to be crucial for TMED 10 interaction with both ALK5 and T beta RII. Synthetic peptides corresponding to this region inhibit both TGF-beta-induced Smad2 phosphorylation and Smad-dependent transcriptional reporter activity. In a xenograft cancer model, where previously TGF-beta was shown to elicit tumor-promoting effects, gain-of-function and loss-of-function studies for TMED10 revealed a decrease and increase in the tumor size, respectively. Thus, we determined herein that TMED10 expression levels are the key determinant for efficiency of TGF-beta receptor complex formation and signaling.
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| 5. |
- Taniguchi, Yoshinori, et al.
(författare)
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Sulfide Capacities of CaO-Al2O3-SiO2 Slags in the Temperature Range 1673 K to 1773 K (1400 A degrees C to 1500 A degrees C)
- 2012
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Ingår i: Metallurgical and materials transactions. B, process metallurgy and materials processing science. - : Springer Science and Business Media LLC. - 1073-5615 .- 1543-1916. ; 43:3, s. 477-484
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Tidskriftsartikel (refereegranskat)abstract
- With a goal to estimate the sulfide capacities of slags used in the pretreatment of hot metal, the sulfide capacities of CaO-Al2O3-SiO2 slags were measured at 1673 K to 1773 K (1400 A degrees C to 1500 A degrees C). The gas-slag equilibrium technique has been used for this measurement. From the results obtained, it was found that the temperature dependence of the sulfide capacity of this slag is independent of the slag compositions. Therefore, a new empirical model based on optical basicity for sulfide capacity estimation of this slag was developed using the measured values of the current work and literature. With the use of the new model, the isosulfide capacity curves at 1673 K (1400 A degrees C) were mapped.
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