Crystal structure of intermetallic compound Y5Co19 and its hydride phases

Y–Co intermetallic compounds and their hydrides were investigated as magnetic materials, but the hydrogenation of these alloys was not observed. We established the existence of Y₅Co₁₉ in the phase diagrams of the Y–Co system. Y₅Co₁₉, an intermetallic compound, was synthesized and its crystal structure was determined by the Rietveld refinement of X-ray diffraction (XRD) data. The structural model of Y₅Co₁₉ is a Ce₅Co₁₉-type model with lattice parameters a = 0.4994 (1) nm and c = 4.800 (1) nm. The crystal structure of the original alloy and its hydride phase is closely related to the hydrogen absorption–desorption property. The hydrogen capacity of Y₅Co₁₉ was 0.63 H/M, while two plateaus were observed in the P–C isotherm. We discovered two hydride phases: Y₅Co₁₉H_3.8 (phase I) and Y₅Co₁₉H_14.9 (phase II), and the structural model of these phases (I and II) was Ce₅Co₁₉-type, which was the same as the original alloy. The unit cell of phase I showed an expansion of 3.9% only along the c-axis from the original alloy, whereas that of phase II indicated an expansion along the a- and c-axes. Additionally, a close isotropic expansion was observed in phase II.     

Multi-component topology optimization for die casting (MTO-D)

Structural and Multidisciplinary Optimization - This paper presents a multi-component topology optimization method for the structural assemblies that are made of components produced by die casting...     

Effect of chemical vapor deposition of toluene on gas separation performance of carbon molecular sieve membranes

Journal of Porous Materials - A carbon molecular sieve (CMS) membrane is a microporous membrane that can serve as a molecular sieve. Tuning the pore size of a CMS membrane to improve the...     

Multifunctional Noncontact Micromanipulation Using Whirling Flow Generated by Vibrating a Single Piezo Actuator

A noncontact method that can achieve immobilization, transportation, and rotation in the microscale is desired in biological micromanipulation. A multifunctional noncontact micromanipulation method is proposed here based on a vibration‐generated whirling flow. Resonance of a cantilever structure is utilized to extend the straight vibration of a single piezo actuator to the 2D circular vibration of a micropipette. The circular vibration in fluids can generate the whirling flow featured with low pressure in the core area and flow velocity gradient. The low pressure can immobilize the objects nearby and transport them together with the micropipette, and the flow velocity gradient is utilized to form a torque to rotate the immobilized object. Experiments of the microbeads are conducted to evaluate the claimed functions and quantify the key parameters that influence the rotation velocity. The cell spheroid is immobilized and rotated for 3D observation, and by assessing the viability of the cells containing in the spheroid, the proposed method is proved noninvasive to living cells. Finally, another important application in operations of mouse egg cells is shown, which indicates that the proposed method is a potential valuable tool in biological micromanipulation.     

Practical rearrangement methods for dynamic double‐array dictionaries

Double‐array structures have been widely used to implement dictionaries with string keys. Although the space efficiency of dynamic double‐array dictionaries tends to decrease with key updates, we can still maintain high efficiency using existing methods. However, these methods have practical problems of time and functionality. This paper presents several efficient rearrangement methods to solve these problems. Through experiments using real‐world datasets, we demonstrate that the proposed rearrangement methods are much more practical than existing methods.     

Novel directional projection screen using divergent corner cube retroreflector with a three‐sided curved surface (D‐CCR)

We devised and developed a novel directive projection screen for applications such as personal use, small group meeting, automotive pillar, and near‐eye. This screen reflects diffused light at an angle Δθ_view around a direction deviated by θ_view from the direction of the projector. By applying this screen to automobiles, for example, by installing a projector at a position slightly shifted from the driver, it is possible to reflect the projected light with high efficiency to a certain range around the face of driver. To realize such a characteristic, a hollow corner cube retroreflector (CCR) was modified as follows. The bottom surface of the CCR was tilted by θ_view/2 to change the direction of the reflected light by θ_view from the retroreflection direction. In addition, three sides' surfaces of the CCR were curved, so that the light to be diffused within a designed angle (θ_view ± Δθ_view/2). The novel retroreflector CCR (D‐CCR) has a single divergent surface with a three‐sided curved surface. We fabricated a prototype with θ_view = 10° and Δθ_view = 16° (i.e., the viewing angle for a single D‐CCR, 10° ± 8°), simulated, and measured its optical properties. We closely confirmed the desired characteristics in which an optical gain of 16 was obtained.     

Highly hydrogen permeable Nb–Ti–Co hypereutectic alloys containing much primary bcc-(Nb,Ti) phase

In order to develop alloys combing high hydrogen permeability with large resistance to the hydrogen embrittlement, microstructures and hydrogen permeability (Φ) have been investigated for the as-cast alloys on the straight line connecting the eutectic {TiCo + (Nb, Ti)} phase and the Nb-rich primary (Nb, Ti) phase in the Nb–Ti–Co system. The alloys on the above-mentioned line consist of the TiCo compound and the (Nb, Ti) solid solution. The value of Φ increases with increasing temperature and volume fraction of the primary (Nb, Ti) phase. The most Nb-rich Nb₆₀Ti₂₁Co₁₉ alloy shows the highest Φ value of 3.99 × 10⁻⁸ (mol H₂m⁻¹ s⁻¹ Pa^−0.5) at 673 K, which is 2.6 times higher than that of pure Pd. The present work demonstrates that highly hydrogen permeable alloys are obtainable in the Nb rich Nb–Ti–Co ones on the straight line connecting the eutectic {TiCo + (Nb, Ti)} phase and the Nb-rich primary (Nb, Ti) phase.     

Comparison of Foliar Spray Efficacy of Electrolytically Ozonated Water and Acidic Electrolyzed Oxidizing Water for Controlling Powdery Mildew Infection on Cucumber Leaves

We investigated and compared the effects of foliar sprays of electrolytically ozonated water (OW) and acidic electrolyzed oxidizing water (AEOW) on severity of powdery mildew infection (PMI) and occurrence of visible physiological disorder on cucumber leaves. Foliar spray of OW contained severity of PMI to almost the same level as the initial value, without any visible physiological disorder. Although severity of PMI on AEOW-sprayed leaves was significantly lower than on OW-sprayed leaves, the leaves showed a visible physiological disorder after the first spray. These results indicate that OW is a viable option for controlling PMI on cucumber leaves at low initial severity levels, or for prevention of PMI, and that AEOW can be used for controlling PMI with special efforts taken against a visible physiological disorder.     

Spark Plasma Sintering of Sol–Gel Derived Amorphous ZrW2O8 Nanopowder

Dense ZrW₂O₈ was prepared by spark plasma sintering (SPS), using amorphous ZrW₂O₈ nanopowder as a raw material, at 873 K for 10 min. We investigated the effects of SPS conditions, such as sintering temperature, heating rate, and the discharge power that is expressed as the product of pulsed direct current and voltage, on the densification process of ZrW₂O₈. The relative density and microstructure of ZrW₂O₈ prepared by SPS were compared with those of ZrW₂O₈ prepared by hot pressing (HP). The relative density of ZrW₂O₈ prepared by HP at 873 K for 1 h was 63.1%. On the contrary, the relative density of ZrW₂O₈ prepared by SPS at 873 K for 10 min at a heating rate of 50 K/min was 98.6%. These results show that the discharge pressure that is proportional to discharge power enhances the densification and grain growth of ZrW₂O₈ in the SPS process.