A holonic control system based on a universal learning network

A new control method is presented using the holonic concept on a universal learning network (ULN). The holonic concept was proposed by Arthur Koestler in 1905. Its aim is to harmonize entire systems with partial systems that have hierarchal structures. On the other hand, a ULN that models and controls large-scale complicated systems such as industrial plants and, economic, social, and life phenomena is proposed. In this paper, a holonic control system based on the holonic concept and ULN is presented. From simulation results from a nonlinear crane system, it has been proved that holonic control can harmonize the system rather than optimize it, which used to be the conventional method in control engineering.     

Mechanical and thermal properties of Zr-B and Fe-B alloys

ABSTRACT

After the core meltdown in the Fukushima Daiichi (1F) nuclear power plant, various compounds in metal boride systems could potentially form as a result of the reactions between B₄C (control material) and Fe, Zr alloys (control-blade sheaths, zircaloy claddings, channel box, etc.). Some previous studies have focused on the properties of intermetallic compounds of the Zr-B and Fe-B systems, such as ZrB₂, FeB, and Fe₂B. However, during the solidification of fuel debris, composites of these intermetallics rather than large chunks of single-phase intermetallics will form. This situation makes the understanding of the composition dependence of the mechanical and thermal properties of these metal borides a major task before debris retrieval takes place. In this study, we first investigated the temperature-dependent thermal conductivity of Fe-B and Zr-B eutectics from room temperature up to 900^°C. We were then able to evaluate the composition-dependent indentation hardness of these metal borides at room temperature. Based on our experimental data, we concluded that the hardness and thermal conductivity of the Fe-B, Zr-B composites can be well estimated using the properties of the composites’ corresponding components, with Rule of Mixtures and Effective Medium Theory (EMT) calculations, respectively.     

Interface properties of SiOxNy layer on Si prepared by atmospheric-pressure plasma oxidation-nitridation

SiO_xN_y films with a low nitrogen concentration (< 4%) have been prepared on Si substrates at 400°C by atmospheric-pressure plasma oxidation-nitridation process using O₂ and N₂ as gaseous precursors diluted in He. Interface properties of SiO_xN_y films have been investigated by analyzing high-frequency and quasistatic capacitance-voltage characteristics of metal-oxide-semiconductor capacitors. It is found that addition of N into the oxide increases both interface state density (D_it) and positive fixed charge density (Q_f). After forming gas anneal, D_it decreases largely with decreasing N₂/O₂ flow ratio from 1 to 0.01 while the change of Q_f is insignificant. These results suggest that low N₂/O₂ flow ratio is a key parameter to achieve a low D_it and relatively high Q_f, which is effective for field effect passivation of n-type Si surfaces.     

Pyrolytically prepared carbon from fluorine-GIC

Formation mechanism, crystallinity, porosity and chemical reactivity were studied on the carbon prepared by pyrolysis of single phase, stage-1 fluorine-graphite intercalation compound (fluorine-GIC; C_xF). The stage-1 C_2.5F directly decomposes to fluorocarbon gases and carbon above 650 K, without forming higher stage compounds. The pyrocarbon prepared from C_2.5F gives hkl diffraction peaks indicating graphite-like stacking order of graphene layers. This carbon possesses average crystallite sizes along the c- and a-axes (L_c and L_a) of about 5 and 50 nm, respectively. The specific surface area of the pyrocarbon (about 40 m² g⁻¹) is only twice as large as that of the original crystalline graphite. Chemical behavior of the pyrocarbon as an intercalation host for sodium and potassium is similar to that of crystalline graphite, but it is easily fluorinated by elemental fluorine even at 573 K to give poly(carbon monofluoride) [(CF)_n] probably due to the small crystallite size and the mesopores formed by formation/decomposition processes of C_2.5F.     

Effect of pH in hydrothermal treatment of as-synthesized MCM-41 on wetting stability of resulting materials in aqueous solution

Effect of pH in aqueous media used in the hydrothermal treatment of as-synthesized MCM-41 on the structure and the wetting stability of the resulting materials was studied using XRD, TG-DTA and N₂ adsorption. The long-range structural order and the wetting stability of the mesoporous MCM-41 were improved through hydrothermal treatment of as-synthesized sample at around pH 7 without salt addition. The pH adjustment of aqueous media toward neutral is thought to shift the polymerization equilibrium of silica species around external surface of the micelles to a higher degree of condensation, and to reduce the electrostatic repulsion between the silicate–micelle composites. This leads to the further formation of Si–O–Si network within the silica walls of the mesoporous materials, resulting in the enhancement of the structural stability of MCM-41 samples.     

Comparative studies of circulating KL-6, type III procollagen N-terminal peptide and type IV collagen 7S in patients with interstitial pneumonitis and alveolar pneumonia

KL-6, a MUC1 mucin preferentially expressed in regenerating type 2 pneumocytes, has been reported to be a sensitive serum marker for evaluating the disease activity of interstitial pneumonitis (IP). Type III procollagen N-terminal peptide (PIIIP) and type IV collagen 7S (7S collagen) have also been reported to be useful in the serological evaluation of the activity. Their levels were measured and their serodiagnostic values were compared simultaneously in patients with IP and alveolar pneumonia. The study population was 45 patients with IP and 12 patients with alveolar pneumonia. Serum KL-6 levels were measured by a specific enzyme immunoassay, and both serum PIIIP and 7S collagen concentrations by their correspondent radioimmunoassay kits. There were no significant difference of serum C-reactive protein level, which was evaluated as an indicator of inflammatory process, between IP and alveolar pneumonia patients. In IP, the abnormally elevated rate of KL-6 [80% (36/45)] was significantly higher than those of PIIIP [40% (18/45)] and 7S collagen [40% (18/45)]. In alveolar pneumonia, the rate of KL-6 [0% (0/12)] was significantly lower than those of PIIIP [33% (4/12)] and 7S collagen [25% (3/12)]. There were no significant correlations among serum levels of the markers. These observations indicate that the serodiagnostic value of KL-6 for IP is superior to that of PIIIP and 7S collagen, and that KL-6 has a characteristic to discriminate IP from alveolar pneumonia.     

Hot shear spinning of cast aluminium alloy parts

A hot shear spinning process of cast aluminium alloy parts was developed to eliminate casting defects and to obtain a desired distribution of wall thickness. The forming load of the shear spinning is comparatively low even for large deformation requisite for eliminating the casting defects. Dendrites and shrinkage cavities in the cast aluminium alloys were successfully eliminated without occurrence of a fracture by the hot shear spinning. Surface cracks around the corner of the mandrel caused by large shear deformation were reduced by decreasing the feed rate of the roller and by increasing the tip radius of the roller. It was found that hot shear spinning is effective in improving the mechanical properties of cast aluminium alloys parts.     

Effect of Metal Ion Addition in a Ni Supported Ga2O3 Photocatalyst on the Photocatalytic Overall Splitting of H2O

The effects of the addition of a metal ion in a Ni supported Ga₂O₃ photocatalyst on the photocatalytic overall splitting of H₂O were investigated. The addition of Ca, Cr, Zn, Sr, Ba and Ta ions were effective in improving the photocatalytic activity. Particularly, the addition of the Zn ion improved the photocatalytic activity remarkably. The states of the photocatalyst after the addition of Zn ion are discussed.     

Orbital view concept applied on photoswitching systems

Diarylethenes are a class of photochromic molecules whose conductance switches with their photoisomerization. We have investigated the conductance of diarylethenes using non-equilibrium Green's function method combined with Hückel method (NEGF–HMO) and density functional theory (NEGF–DFT). In this study we have found that the qualitative predictions based on frontier orbital analysis are consistent with the DFT calculations and can be used for prediction of the electron transport properties of molecular devices.     

Novel strengthening method of closed-cell aluminum foams through surface treatment by resin

Aluminum foams are focused on as a lightweight structural material because of their excellent energy absorbing capacity. However, compressive strength of aluminum foams is much lower than that of dense aluminum. This is due to local buckling of the inhomogeneous cell structure. The authors carried out infiltration of open surface pores with polyester resin because buckling starts at the open surface pores. Compressive tests using commercial aluminum foams show significant increases in compressive strength and absorbed energy. Since the density of resin is not high, the specific compressive strength and specific absorbed energy are also increased.