TRACKING DOMAINS FOR UNSTABLE PLANTS WITH SATURATING-LIKE ACTUATORS

In many mechanical systems, the tracking control is one of the most important issues. Therefore for the unstable system subject to actuator saturation, the domain of the initial states corresponding to an arbitrary reference signal, within which tracking condition can be achieved, is interesting to be considered. In this paper, an approximate tracking domain is derived analytically. First in Theorem 1, for simple case, it is constructed by using the partial Lyapunov function and the absolute stability theory. In the following Theorems 2 and 3, a new idea is used to obtain larger domains. Finally in the last section, a simple numerical example is given.     

Team performance modeling for HRA in dynamic situations

This paper proposes a team behavior network model that can simulate and analyze response of an operator team to an incident in a dynamic and context-sensitive situation. The model is composed of four sub-models, which describe the context of team performance. They are task model, event model, team model and human–machine interface model. Each operator demonstrates aspects of his/her specific cognitive behavior and interacts with other operators and the environment in order to deal with an incident. Individual human factors, which determine the basis of communication and interaction between individuals, and cognitive process of an operator, such as information acquisition, state-recognition, decision-making and action execution during development of an event scenario are modeled. A case of feed and bleed operation in pressurized water reactor under an emergency situation was studied and the result was compared with an experiment to check the validity of the proposed model.     

Effect of friction,strain hardening,and strain rate hardening on the metal flow in rod extrusion

The metal flow in a rod extrusion is theoretically discussed in relation to a frictional condition, strain hardening and strain rate hardening. An existing rigid plastic FEM-program was modified in order to take a rate sensitivity of a material into consideration through a constitutive equation of the form. An interfatial friction was incorporated by a constant Coulomb-frictional coefficient. When the frictional coefficient is smaller than 0.1, a large effect of the friction does not appear. The larger the n-value is, the stronger the distortion of the grid in a billet becomes even under small frictional resistance. The effect of the m-value is similar qualitatively to that of the n-value. When the rate sensitive material is extruded at very low punch speed under large frictional resistance, the material is strained very irregularly all over the billet at an early stage.     

Abrupt changes in cross polarizations observed during thunder

Abrupt changes in the cross-polarization discrimination (XPD) and cross-polar phase were observed in cross-polarization measurements at 4, 6, and 11 GHz on propagation paths with low elevation angles. These abrupt changes were always observed during thunder, though exact time-to-time correspondence with lightning strokes was not clear in the measurement. In most cases, these sudden changes occurred in the direction in which the distortion of polarization ellipse increases, and the rate of change in XPD was much faster than rain-induced depolarizations by an order of magnitude. Based on the simultaneous measurement of circular and linear polarizations at 11 GHz, it was also found that the differential phase shift component suddenly increased to as large as20degto40degupon occurrence of these XPD changes, which confirms that this phenomenon is attributed to the effect of ice particles.     

Solution Property and Irradiation Effect of Random Copolypeptides Composed of Ala and Pro Residues

Summary Poly(proline) and random copolypeptide composed of Pro and Ala residues were synthesized, and their solution properties and molecular conformation were investigated. Aqueous solutions of the polypeptide were irradiated with γ-rays above the transition temperature. It was shown that the transition temperature of the aqueous solution of the copolypeptide is influenced by Ala-residue content and γ-ray irradiation.     

Cholelithiasis in hamsters: Effects of cholic acid and calcium on gallstone formation

Dietary cholic acid (0.1%) and/or calcium (2.6% as calcium carbonate) were added to a semipurified diet containing cholesterol and ethynyl estradiol to determine whether the incidence of pigment and/or cholesterol gallstones would be changed. Male golden Syrian hamsters were fed the experimental diets for 96 days (Group 1, control; Group 3, cholic acid plus calcium) or only an average of 60 days (Group 2, 0.1% cholic acid). Animals in Group 2 became ill (weight loss, low food intake, diarrhea) possibly due to cholic acid (or deoxycholic acid) toxicity. Cholesterol gallstones and crystals were absent in all experimental groups. The incidence of pigment gallstones was: control, Group 1, 12/16; 0.1% cholic acid, Group 2, 3/13; and 0.1% cholic acid plus calcium, Group 3, 11/22. Cholic acid with or without calcium produced an elevation of both liver and plasma cholesterol: Group 2, 80.1 mg/g and 501 mg/dl; Group 3, 103.7 mg/g and 475 mg/dl vs Group 1, 65 mg/g and 209 mg/dl, respectively. The lithogenic indices of the bile were lower in Groups 2 and 3 compared to Group 1, controls, 0.45 and 0.58 vs 1.16, respectively. The extent of the portal tract pathology could not be correlated with the presence or absence of pigment gallstones or with the levels of lithocholic acid in the hamster bile. In summary, when semipurified diets were supplemented with ethynyl estradiol and cholic acid, with and without calcium supplementation, no cholesterol gallstones formed and the incidence of pigment gallstones was not altered.     

Effect of heating process on the formation of nanoparticles of elastin model polypeptide, (GVGVP)251, by gamma-ray crosslinking

Nanoparticles were prepared by the thermosensitive aggregation of the elastin model polypeptide, (GVGVP)₂₅₁, and gamma-ray crosslinking. Three different heating processes, “slow heating,” “fast heating,” and “heat shock,” were used for the aggregation of the peptide, followed by gamma-ray crosslinking. Only the “heat shock” process successfully yielded stable nanoparticles with diameters of less than ca. 150 nm and a narrow size distribution. Circular dichroism (CD) spectrometry showed that this polypeptide formed a type-II β-turn structure when the temperature was increased to above the cloudy point in the case of the “heat shock” process; suggesting that this structure might contribute to stable nanoparticle formation by gamma-rays. CD spectrometry also suggested that this structure would be affected during the formation of stable crosslinked particles.     

Characterization of endotoxic indicative organic matter (2-keto-3deoxyoctulosonic acid) in raw and biologically treated domestic wastewater

The aim of this research is to characterize the organic matter showing endotoxicity in domestic wastewater. It is assumed that endotoxicity is caused by lipo-polysaccharide (LPS), particularly large and hydrophobic molecules. In this study, a batch experiment (decay test for 12 h) was conducted to confirm whether LPS is the cause of endotoxicity or not. 2-keto-3deoxyoctulosonic acid (KDO) was used as an indicator of presence of LPS.A size and structural characterization of several samples from raw and domestic wastewater was also carried out in order know which fractions are causing endotoxicity. Endotoxin and KDO patterns were found to be similar, peaking at the same time. Thus, organic matter showing endotoxicity, such as LPS was released in the decay test. Moreover, the organic matter released from bacteria during decay test was partly biodegradable. Results from size characterization (Molecular Weight Distribution) showed that the majority of endotoxin (up to 82%), in domestic sewage and secondary effluents,is composed of molecules larger than 100 kDa and less than 0.1 μm. Similarly, structural characterization (hydrophobic and hydrophilic) showed that the majority of endotoxin, ranging from 59% to 83% of the total endotoxicity, is hydrophobic fractions. Therefore, removing large and hydrophobic molecules from wastewater can be an effective way to achieve a significant decrease in its endotoxicity.     

Spin Dynamics in ZnO-Based Materials

In this work, we address the issue of spin relaxation and its relevance to spin detection in ZnO-based materials, by spin-polarized, time-resolved magneto-optical spectroscopy. We have found that spin relaxation is very fast, i.e. about 100 ps for donor bound excitons in wurtzite ZnO, despite of a weak spin–orbit interaction. We also reveal that alloying of ZnO with Cd enhances spin relaxation, prohibiting ZnCdO/ZnO structures for efficient optical spin detection. On the other hand, a variation in strain field induced by lattice mismatch with substrates does not seem to lead to a noticeable change in spin relaxation. The observed fast spin relaxation, together with the limitation imposed by the band structure, are thus identified as the two most important factors that limit the efficiency of optical spin detection in the studied ZnO-based materials.