The Remaining Refractory Thickness Assessment of Hearth Part in the Blast Furnace

In the steel industry, the blast furnace is a process for making molten iron by melting iron ore. The blast furnace body is a huge structure of 50m in height, 20m in width. It should be operated not less than 15 years during one campaign. The structural problems of this blast furnace are cracks of the steel shell and thickness reductions of the stave and the refractory of hearth part caused by wear. Among them the thickness reduction of the hearth refractory in the blast furnace is very important factor in determining the dismantlement and the reconstruction of the blast furnace. Conventionally, the thermal model was used to estimate the residual thickness and to monitor the temperature of refractory with thermocouples installed on the refractory. Recently, Impact Echo method is being applied to measure the residual thicknesses of concrete or nonmetallic stiff structures. The method should be accompanied with verification in the actual blast furnace since there are differences in the reflection characteristics of the ultrasonic velocity depending on physical parameters of the steel shell, the refractory and ramming part between the steel shell and the refractory such as the size, the shape, the temperature, the consisting materials and etc. In this study, we compared various sensors such as accelerometer, a microphone and an ultrasonic sensor and the experimental methods in determining the ultrasonic velocity of the anisotropic refractory material. In addition, measuring refractory thickness of the actual blast furnace was carried out before dismantling and verified with exact thickness of refractory by means of measuring length of the core-boring sample and dismantling investigatio

Dynamical mean-field theory of Hubbard-Holstein model at half-filling: Zero temperature metal-insulator and insulator-insulator transitions

We study the Hubbard-Holstein model, which includes both the electron-electron and electron-phonon interactions characterized by $U$ and $g$, respectively, employing the dynamical mean-field theory combined with Wilson's numerical renormalization group technique. A zero temperature phase diagram of metal-insulator and insulator-insulator transitions at half-filling is mapped out which exhibits the interplay between $U$ and $g$. As $U$ ($g$) is increased, a metal to Mott-Hubbard insulator (bipolaron insulator) transition occurs, and the two insulating states are distinct and can not be adiabatically connected. The nature of and transitions between the three states are discussed.Comment: 5 pages, 4 figures. Submitted to Physical Review Letter

Distribution of stone cell in Asian, Chinese, and European pear fruit and its morphological changes

This study was conducted to microscopically verify the distribution and morphological changes occurring in stone cells during fruit growth in order to determine physiological changes occurring in stone cells in pear fruits. European pear (P. communis L. cv. ‘Bartlett’), Chinese pear (P. bretschneideri Rehd. cv. ‘Yali’), and Asian pear (P. pyrifolia Nakai cv. ‘Niitaka’) were collected from three trees of each cultivar for microscopic observation at 60 DAFB. Also, ‘Niitaka’ pear fruits were harvested at development stages of 30, 60, 90 and 150 DAFB. Stone cells were observed via light microscopy (LM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The stone cells were found to be clustered less profoundly in the ‘Niitaka’ and ‘Yali’ pears than in ‘Bartlett’ pears, and the sizes of the clusters were smaller. Also, the stone cells were clustered closer to the epidermis in the ‘Niitaka’ and ‘Yali’ pears than in the Bartlett pears. Stone cells appeared in cluster structures beginning at 60 DAFB. The relative decrease in the quantity of stone cell clusters in the flesh was attributed to the fact that stone cells were no longer being generated, and the flesh cells increased dramatically in size. Developing and completed stone cells existed together within the same stone cell cluster

Observation and analysis of low temperature leak characteristics of the O-ring for hydrogen electric vehicles

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Role of G{alpha}12 and G{alpha}13 as Novel Switches for the Activity of Nrf2, a Key Antioxidative Transcription Factor

G{alpha}12 and G{alpha}13 function as molecular regulators responding to extracellular stimuli. NF-E2-related factor 2 (Nrf2) is involved in a protective adaptive response to oxidative stress. This study investigated the regulation of Nrf2 by G{alpha}12 and G{alpha}13. A deficiency of G{alpha}12, but not of G{alpha}13, enhanced Nrf2 activity and target gene transactivation in embryo fibroblasts. In mice, G{alpha}12 knockout activated Nrf2 and thereby facilitated heme catabolism to bilirubin and its glucuronosyl conjugations. An oligonucleotide microarray demonstrated the transactivation of Nrf2 target genes by G{alpha}12 gene knockout. G{alpha}12 deficiency reduced Jun N-terminal protein kinase (JNK)-dependent Nrf2 ubiquitination required for proteasomal degradation, and so did G{alpha}13 deficiency. The absence of G{alpha}12, but not of G{alpha}13, increased protein kinase C {delta} (PKC {delta}) activation and the PKC {delta}-mediated serine phosphorylation of Nrf2. G{alpha}13 gene knockout or knockdown abrogated the Nrf2 phosphorylation induced by G{alpha}12 deficiency, suggesting that relief from G{alpha}12 repression leads to the G{alpha}13-mediated activation of Nrf2. Constitutive activation of G{alpha}13 promoted Nrf2 activity and target gene induction via Rho-mediated PKC {delta} activation, corroborating positive regulation by G{alpha}13. In summary, G{alpha}12 and G{alpha}13 transmit a JNK-dependent signal for Nrf2 ubiquitination, whereas G{alpha}13 regulates Rho-PKC {delta}-mediated Nrf2 phosphorylation, which is negatively balanced by G{alpha}12