Crystal orientation of β-phase isotactic polypropylene induced by magnetic orientation of N,N′-dicyclohexyl-2,6-naphthalenedicarboxamide

Melt crystallization of isotactic polypropylene (iPP), containing crystallites of N,N′-dicyclohexyl-2,6-naphthalenedicarboxamide (DCNDCA) as a nucleating agent of the the β-phase iPP crystal, is carried out under a magnetic field (6 T) to obtain the alignment of the iPP crystal induced by magnetic alignment of DCNDCA. In a previous paper, DCNDCA was reported to undergo magnetic alignment in a liquid suspension. The obtained iPP sample exhibits alignment of the β-phase crystal with the c-axis aligned perpendicular to the magnetic field. The comparison of this alignment of iPP with the reported magnetic alignment of DCNDCA indicates that the β-phase crystal grows epitaxially on the DCNDCA crystal. The (330)_β plane of the iPP crystal lies on the bc-plane of the DCNDCA crystal in which the direction of the c-axis of the iPP coincides with the direction of the b-axis of the DCNDCA crystal.     

Mechanochemically synthesized ZIF-8 nanoparticles blended into 6FDA-TrMPD membranes for C3H6/C3H8 separation

The mixed matrix membranes (MMMs) consisting zeolitic-imidazolate framework-8 (ZIF-8) nanoparticles in a polymer have been of considerable interest in separation applications. The fillers used are mostly synthesized using the solvothermal method. In this study, the ZIF-8 nanoparticles were synthesized using a solvent-less and salt-free mechanochemical method and were added to 6FDA-TrMPD polyimide to prepare MMMs. The single gas permeation of C₃H₆ and C₃H₈ through the MMMs was investigated. The C₃H₆ permeability and C₃H₆/C₃H₈ ideal selectivity of a 20 wt% mechano-synthesized ZIF-8/6FDA-TrMPD MMM were 70% and 32% higher than those of the neat polymer membrane at 0.1 MPa and 308 K, respectively. The C₃H₆/C₃H₈ separation performance of the mechano-synthesized ZIF-8 MMM was similar to that of the conventional solvothermal-synthesized ZIF-8 MMM. This separation performance was in good agreement with the Maxwell model. Temperature and pressure dependence analyses confirmed that the mechano-synthesized ZIF-8 nanoparticles acted as molecular sieves in the MMMs for the C₃H₆ and C₃H₈ permeation.     

Two-step design of critical control systems using disturbance cancellation integral controllers

An efficient critical control system design is proposed in this paper. The key idea is to decompose the design problem into two simpler design steps by the technique used in the classical loop transfer recovery method (LTR). The disturbance cancellation integral controller is used as a basic controller. Since the standard loop transfer recovery method cannot be applied to the disturbance cancellation controller, the nonstandard version recently found is used for the decomposition. Exogenous inputs with constraints both on the amplitude and rate of change are considered. The majorant approach is taken to obtain the analytical sufficient matching conditions. A numerical design example is presented to illustrate the effectiveness of the proposed design.     

Physical indices for judging appearance harmony of materials

In visual design, harmony refers to the similarity among objects and the components of these objects that appear as if they belong together. Harmony is related to the body, mind, and emotions as we relate to our living space, which means that the harmony of real objects is an important characteristic. Although the appearance harmony in specific materials has been investigated, harmony among different materials has not received adequate attention. In a previous study, we investigated the appearance harmony among various materials by psychophysical experiments. In this study, we correlated the psychophysical evaluations obtained from the experiments and the physical properties of the materials. By analyzing the relationship between psychophysical evaluations and the physical measurements for each material pairs based on cluster analysis, we found that the property of texture represented by the anisotropy histogram and that of reflectance obtained from the data of the bidirectional reflectance distribution function are important indices that can be used to judge the harmony of materials. In particular, the texture properties were more effective in judging the appearance harmony of material pairs in the fixed condition for illumination and viewing angles, and the reflectance properties were superior for the material pairs in the variable condition for illumination and viewing angles.     

Investigation of metallic color perception using real‐world materials

Metallic colors have a unique appearance of glossiness with features such as highlights, contrast, and reflections on their surface, and therefore, metallic objects are very attractive to humans. Especially, gold, silver, and copper colors are familiar metals used as decorative materials, coins, and other furnishings. However, the mechanism and condition of metallic perception have not been fully investigated. There are a few studies for investigating metallic perception using rendered patches or images, but there is no study using real‐world objects. In our previous study, we developed a simple representation technique that made real objects appear to be made of gold by projecting a solid color onto a target nonmetallic object. By using the representation technique, in this study, we have further investigated the perception of metallic appearance such as gold, silver, and copper using real‐world materials, and analyzed the difference between these metallic perceptions. Our results indicate that the perception of the metallic object is different for gold, silver, and copper. Our new findings are as follows: the glitter required for the perception of gold and silver becomes an obstacle to the perception of copper; the metallic perception reveals that learning experience might be strongly affecting; and luminance adjustment is sensitive to the perception of metallic objects.     

Performance Comparison of Circuits for Pole‐Mounted STATCOM Using SiC Devices

The recent years have seen an increasing trend in the cumulative installed capacity of distributed generators. As a result, voltage management may become difficult in existing power distribution systems in the future. A STATCOM (STAtic synchronous COMpensator) is a promising option for solving this problem because it can control reactive power rapidly and continuously. For a distribution system, STATCOM needs to be pole‐mounted to realize its low cost. However, a transformer for a STATCOM is large and heavy, and hence it is difficult to install a STATCOM on a distribution pole. We adopt a transformerless STATCOM to reduce STATCOM size and use SiC devices with low‐loss performance to obtain a more compact and efficient STATCOM. There are a large number of circuits available for a STATCOM, and there has been considerable research on performance comparisons among these circuits. However, these comparisons were drawn under different conditions, including switching frequency and level number for the circuits. In addition, these comparisons do not include the use of SiC devices. We made an equitable comparison for a 100 kVa pole‐mounted STATCOM using SiC devices. We discuss the performance and characteristics of each circuit in terms of efficiency and volume.     

Predictive Simulation of Deformation and Failure of Peat-Calcareous Soil Layered Ground Due to Multistage Test Embankment Loading

The continuous behaviour of a ground-embankment system from the stage of deformation up to failure was predicted with respect to an actual test embankment that had been constructed in stages on a soft ground made up of peat and calcareous soil. The behaviour prediction was carried out by employing soil-water coupled finite deformation analysis, which also included simulation of the embankment construction process. The information used in the analysis was limited to such things as the results of soil tests on soil materials (peat and calcareous soil) sampled from the ground, including their sensitivity ratios, and the embankment's construction history. The SYS Cam-clay model was used in the constitutive equations of the soils to determine the material constants of the soils and the initial conditions of the ground, and the computations were performed under plane strain conditions. As a result, the computed profiles of W-type ground settlement and of slip surfaces running through the embankment were found to be in good overall agreement with the actual profiles measured at the site. Furthermore, we found that this slippage is attributable to the undrained shear response of the soil elements in the calcareous soil layer, where slippage begins to occur during embankment loading. In other words, the slippage is caused by the rapid softening behaviour caused by the degradation of structure after the effective stress ratio reaches the vicinity of the critical state line.     

Spatial mapping of electronic states in κ-(BEDT-TTF)2X using infrared reflectivity

We review our recent work on spatial inhomogeneity of the electronic states in the strongly correlated molecular conductors κ-(BEDT-TTF)₂X. Spatial mapping of infrared spectra (SMIS) is used for imaging the distribution of the local electronic states. In molecular materials, the infrared response of the specific molecular vibration mode with a strong electron–molecular vibration coupling can reflect the electronic states via the change in the vibration frequency. By spatially mapping the frequency shift of the molecular vibration mode, an electronic phase separation has been visualized near the first-order Mott transition in the bandwidth-controlled organic conductor κ-(BEDT-TTF)₂Cu[N(CN)₂]Br. In addition to reviewing SMIS of the phase separation, we briefly mention the electronic and optical properties of κ-(BEDT-TTF)₂X.     

Monitoring cure of autoclave-molded parts by dielectric analysis

A study was undertaken to determine the feasibility of using dielectric analysis as a means of monitoring and controlling cure of large closures during autoclave molding. In dielectric analysis, the dissipation factor (DF) and capacitance (C) of the sample are continuously monitored as a function of time, temperature, and frequency. Dissipation factor profiles were established for the suppliers' recommended cure cycle and for modified cure cycles, Good reproducibility was obtained in dissipation factor profiles on subsequent scaling up to production size (7 ft · 20 ft) autoclaves. Good correlation was also observed during production runs of fullscale closures. The effects of cure variables on the dissipation factor profiles and on the mechanical properties of the prepared laminates were analyzed for extent of correlation. Results of this study show: (1) dielectric analysis can be used to monitor autoclave cure of composites, and (2) within limits, process control may be feasible.