Model predictive control for line pacing in steel processing

Line pacing control in steel processing lines is known to be a difficult task for operators.?They usually take a conservative control policy in order to avoid shutdown, and the processing capacity of the line has not been fully utilized yet. This paper presents a new modeling and control technique for line pacing based on a hybrid petri net (HPN) and mixed logical dynamical system (MLDS) expressions. The proposed modeling method can harmoniously integrate continuous and discrete aspects of the system. Moreover, the proposed method can provide a suitable formulation for numerical optimization. Based on this hybrid system modeling, the closed‐loop control can be realized by the receding horizon scheme. Numerical examples demonstrate that the processing capacity can be fully utilized by the proposed method. © 2012 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

Improvement of Electrical Contact Between TE Material and Ni Electrode Interfaces by Application of a Buffer Layer

A single ??-structure thermoelectric (TE) module based on p-type NaCo₂O₄, n-type Mg₂Si, and Ni electrode was fabricated by the spark plasma sintering (SPS) method. The NaCo₂O₄ powder was synthesized by using a metal?Ccitric acid complex decomposition method. Bulk Mg₂Si prepared by melt quenching was ground into a powder and sieved to particle size of 75???m or less. To obtain a sintered body of NaCo₂O₄ or Mg₂Si, the powder was sintered using SPS. Pressed Ni powder or mixed powder consisting of Ni and SrRuO₃ powder was inserted between these materials and the Ni electrode in order to connect them, and electrical power was passed through the electrodes from the SPS equipment. The open-circuit voltage (V _OC) values of a single module in which TE materials were connected to the Ni electrodes by using pressed Ni powder was 82.7?mV, and the maximum output current (I _max) and maximum output power (P _max) were 212.4?mA and 6.65?mW at ??T?=?470?K, respectively. On the other hand, V _OC of a single module in which TE materials and an Ni electrode were connected with a mixed powder (Ni:SrRuO₃?=?6:4 volume fraction) was 109?mV, and I _max and P _max were 4034?mA and 109?mW at ??T?=?500?K, respectively. These results indicate that the resistance at the interface between the TE materials and the Ni electrode can be decreased and the output power can be increased by application of a buffer layer consisting of Ni and SrRuO₃.     

Display of the human (pro)renin receptor on Bombyx mori nucleopolyhedrovirus (BmNPV) particles using Bm cells

The human (pro)renin receptor (hPRR) was displayed on the surface of Bombyx mori nucleopolyhedrovirus (BmNPV) with and without fusion to glycoprotein 64 (GP64) of the BmNPV. hPRR1 is a native hPRR with an additional FLAG peptide sequence inserted between the signal peptide and prorenin-binding domain. hPRR2 has the prorenin-binding domain inserted between amino acid residues (81)Asp and (82)Pro of GP64. hPRR4 has the prorenin-binding domain inserted in (81)Asp and (320)Met of partially deleted GP64. Incorporation of hPRR was confirmed in recombinant BmNPV (rBmNPV) but not in cysteine protease-deleted rBmNPV. hPRR1 was observed in ER, but hPRR2 and hPRR4 were observed around the endoplasmic reticulum (ER) and in its periphery. rBmNPV-hPRR1 and -hPRR2, carrying hPRR1 and hPRR2 respectively, showed binding affinity to human renin, but rBmNPV-hPRR4 did not. The presence of hPRR4 of rBmNPV-hPRR4 was confirmed in western blotting under nonreducing conditions, suggesting that although hPRR4 was incorporated in rBmNPV-hPRR4, it behaved as a non-functional aggregate. This rBmNPV display system can also be used for analyzing a ligand-receptor interaction.     

Testosterone inhibits matrix metalloproteinase-1 production in human endometrial stromal cells in vitro

Androgen receptor (AR) is reported to be expressed in human uterine endometrium, but not much information is available on the role of androgens in human endometrium. The purpose of this study is to investigate the role of androgens in the regulation of matrix metalloproteinase (MMP)-1, which is one of the important MMPs for menstruation and embryo implantation in human endometrium. Human endometrial stromal cells (HESCs) were obtained from human endometrium by enzymatic dissociation method. Purified HESCs were incubated with 17beta-estradiol (E2), testosterone, or E2 + testosterone. Progestins (natural progesterone or medroxyprogesterone acetate) or vehicle (dimethyl sulfoxide) were also added to the media instead of testosterone. Furthermore, hydroxyflutamide (FLU),a specific AR antagonist, was also supplemented to cultured media. The amounts of MMP-1 in cultured media and in HESC lysates were examined by ELISA measurements and western blotting analysis respectively. The expression of ARmRNA in HESCs RNA was analyzed by RT-PCR. Testosterone significantly inhibited MMP-1 in both cultured media and cell lysates in a dose-dependent manner. Progestins also inhibited MMP-1. Furthermore, FLU completely recovered the decrease of MMP-1 induced by testosterone. ARmRNA was detected in all HESCs RNA. The present study demonstrated that the secretion and production of MMP-1 in HESCs in vitro were inhibited by testosterone through androgen receptors in a manner similar to that seen for progesterone. These findings indicate that androgen may play an important role in morphological and functional changes of human endometrium.     

Fabrication of colorless organic materials exhibiting white luminescence using normal and excited-state intramolecular proton transfer processes

Organic, white luminescent materials were fabricated using a mixture of proton-transfer and nonproton-transfer fluorophores. 2'-Methoxy and 2'-hydroxy derivatives of 2-phenylimidazo[1,2-a]pyridine (PIP) have similar UV-absorption properties; however, they exhibit mechanistically different luminescence respectively ascribable to the normal (～420 nm) and excited-state intramolecular proton transfer processes (～530 nm) in the solid state. UV-irradiation of mixed solids excites both components concurrently and results in efficient white luminescence composed of two independent emissions without involving energy transfer process. White luminescent solids are easily transformed into vapor-deposited films under mild conditions, and a colorless and transparent thin film by dissolving in PMMA.     

Experimental investigation on self-leveling behavior in debris beds

During a hypothetical core-disruptive accident in a sodium-cooled fast breeder reactor, degraded core materials can form debris beds on the core-support structure and/or in the lower inlet plenum of the reactor vessel from rapid quenching and fragmentation of core material pool. Coolant boiling may lead ultimately to leveling of the debris bed that is crucial to the relocation of molten core and heat-removal capability of the debris bed. In the present study, we elected to use depressurization boiling to simulate an axially increasing void distribution in the debris bed. Bottom-heating boiling was also chosen to confirm that characteristics of the self-leveling process do not depend on the boiling mode. Particle size (between 0.5 and 6 mm), shape (spherical and non-spherical), bed volume (between 5 and 8 l) and density (namely of alumina, zirconia, lead and stainless steel) along with boiling intensity and total volume were taken as experimental parameters to obtain the general characteristics of the self-leveling process. A series of experiments with simulant materials were conducted and analyzed in detail. The good concordance of the transient processes obtained from the different boiling methods sufficiently demonstrates that the present results obtained using the depressurization boiling method exhibit these general self-leveling characteristics. Detailed comparisons of deduced time variations of the inclination angle provides qualitative tendencies based on the experimental parameters considered influential to self-leveling behavior. The rationale behind the definition introduced for equivalent power density is also presented.     

Development of function-graded proton exchange membrane for PEFC using heavy ion beam irradiation

The graded energy deposition of heavy ion beam irradiation to polymeric materials was utilized to synthesize a novel proton exchange membrane (PEM) with the graded density of sulfonic acid groups toward the thickness direction. Stacked Poly(tetrafluoroethylene-co-hexafluoropropylene) (FEP) films were irradiated by Xe⁵⁴⁺ ion beam with the energy of 6 MeV/u under a vacuum condition. The induced trapped radicals by the irradiation were measured by electron spin resonance (ESR) spectroscopy. Irradiated films were grafted with styrene monomer and then sulfonated. X-ray photo-electron spectroscopy (XPS) spectra showed that the densities of sulfonic acid groups were controlled for injection “Surface” and transmit “Back” sides of the fabricated PEM. The membrane electrode assembly (MEA) fabricated by the function-graded PEM showed improved fuel cell performance in terms of voltage stability. It was expected that the function-graded PEM could control the graded concentration of sulfonic acid groups in PEM.     

Levels of glutathione and related enzymes in yellowtail fish muscle subjected to ice storage in a modified atmosphere

We investigated the effects of ice storage in a modified atmosphere on levels of glutathione (GSH) and its related enzyme activities, the metmyoglobin to total myoglobin ratio (metMb%), and the K value (a freshness index) of yellowtail fish muscle. GSH in ordinary muscle (fast skeletal muscle) as well as in dark muscle (slow skeletal muscle) stored in air decreased. GSH in those muscles was almost unchanged during storage when packaged with an oxygen absorber or with an oxygen absorber-CO(2) generator. Glutathione disulfide in each type of packaging remained at low concentrations during storage. The GSH peroxidase activities of ordinary muscle and of dark muscle after 7 d of storage in air were lower than when packaged with the oxygen absorber or with the oxygen absorber-CO(2) generator. The GSH reductase (GR) activities of ordinary muscle at the 4th and 7th day of storage when packaged with the oxygen absorber showed a tendency to be lower than when stored in air. The GR activity of dark muscle in each type of packaging method was unchanged during storage. The packaging method did not influence the K values of either the ordinary muscle or the dark muscle during storage. The metMb% of dark muscle when packaged with the oxygen absorber was lower than in the other types of packaging during storage. Therefore, packaging with the oxygen absorber is an effective method to prevent the loss of GSH in fish meat as well as to reduce the discoloration during storage. PRACTICAL APPLICATION: This study examined whether modified atmosphere packaging preserves the level of GSH, which is unstable to oxidative stress, in fish muscle. The use of an oxygen absorber for packaging can allow us to take in a sufficient amount of the bioactive compound from fish meat after storage as well as fresh fish.     

Catalytic etching of {100}-oriented diamond coating with Fe, Co, Ni, and Pt nanoparticles under hydrogen

Etching of a highly {100}-oriented diamond coating, {100}HODC, with hydrogen gas using Fe, Co, Ni, and Pt nanoparticles as a catalyst was examined at high temperatures over 700 °C by high-resolution scanning electron microscopy and Raman spectroscopy. The metal atoms vacuum-evaporated onto the {100}HODC formed nanoparticles themselves when heated at high temperatures; e.g. 700 °C, in a flowing gas mixture of H₂ (10%) + N₂ (90%). At 800 °C, short nano-channels and etch pits holding metal nanoparticles were formed by Fe, Co, and Ni. The shapes of the Co and Ni nanoparticles in the etch pits were affected by the shape of the etch pits; reversed pyramidal shape. On the other hand, the top view of the Fe nanoparticles embedded in the etch pits showed a distorted round shape, probably due to the formation of something such as iron carbide, while the carbon content was unknown. Apparently, etching of the {100}HODC by Pt nanoparticles was observed after the treatment at 1000 °C. The difference in the catalytic etching behavior among these metal particles, the potential etching mechanism of diamonds with hydrogen by metal nanoparticles, probably as melted metal nanoparticles, and the formation mechanism of vacant etch pits were discussed.