Ideal-Gas Heat Capacity for 2,3,3,3-Tetrafluoropropene (HFO-1234yf) Determined from Speed-of-Sound Measurements

The isobaric ideal-gas heat capacity for HFO-1234yf, which is expected to be one of the best alternative refrigerants for HFC-134a, was determined on the basis of speed-of-sound measurements in the gaseous phase. The speed of sound was measured by means of the acoustic resonance method using a spherical cavity. The resonance frequency in the spherical cavity containing the sample gas was measured to determine the speed of sound. After correcting for some effects such as the thermal boundary layer and deformation of the cavity on the resonance frequency, the speed of sound was obtained with a relative uncertainty of 0.01 %. Using the measured speed-of-sound data, the acoustic-virial equation was formulated and the isobaric ideal-gas heat capacity was determined with a relative uncertainty of 0.1 %. A temperature correlation function of the isobaric ideal-gas heat capacity for HFO-1234yf was also developed.     

Hydrogenation properties and crystal structures of Ti−Mn-V BCC solid solution alloys

We have proposed new hydrogen absorbing alloys of the ‘Laves phase related BCC solid solution alloy’, the hydrogen capacity of which reaches almost double that of conventional rare-earth based AB₅ alloys. We have reported the hydrogen absorbing properties of Ti−V−Mn, Ti−V−Cr and T−V−Mn−Cr alloys. It has been accepted that the crystal structural change of BCC hydrogen absorbing alloys is the same as that of V metal. The mono-hydride (H/M=1) of V metal has a BCT structure and the di-hydride (H/M=2) has an FCC structure. However, we recently found that the Ti−V−Mn alloy shows different behaviors in phase transformation with hydrogenation to V metal. We found three hydride phases with a BCC, a deformed FCC and an FCC structure in the Ti−V−Mn solid solution alloy-H₂ system. The deformed FCC hydride phase has not yet to our knowledge been reported. The lattice constant of the deformed FCC was 0.407 nm, one axis of which is reduced by about 4%. Its single-phase region appeared at a hydrogen content between 0.8 H/M and 1.0 H/M in absorption at 298 K. The lower plateau observed due to formation of the deformed FCC hydride phase gives an increase of effective hydrogen capacity by decreasing hydrogen remaining in the alloy in the desorption process. This article based on a presentation made in the symposium “The 2nd KIM-JIM Joint Symposium: Hydrogen Absorbing Materials”, held at Hanyang University, Seoul, Korea, October 27–28, 2000 under the auspices of The Korean Institute of Metals and Materials and The Japan Institute of Metals.     

Effect of surface roughness on elastohydrodynamic traction: Part 1

The effect of surface roughness on traction performance was experimentally studied using a two‐roller tester. The nature of the contact was investigated using electrical resistance and electrical capacitance methods. Increased shear stress was observed in the viscous region, which could be attributed to a higher average shear rate and to greater viscosity under EHD contact conditions due to pressure fluctuations caused by the surface texture.     

Transmission performance of chirp-controlled signal by usingsemiconductor optical amplifier

We examine the fiber transmission performance of the optical signal whose chirp is controlled by utilizing phase modulation in semiconductor optical amplifier (SOA) with both simulations and experiments. This chirp control technique converts a positive chirp created by electroabsorption (EA) modulator into negative chirp, which reduces the waveform degradation due to the chromatic dispersion in transmission over standard single-mode fiber (SMF). It also provides an optical gain that is sufficient to compensate the insertion loss of the EA modulator. We investigate how the chirp control is affected by the input power to the SOA and the carrier lifetime of the SOA. As the SOA input power increases, the negative chirp becomes large, while the waveform is largely distorted due to gain saturation. However, the waveform distortion at high SOA input powers can be shaped by using a frequency discriminator. The acceleration of the carrier lifetime also reduces the waveform distortion due to gain saturation. We demonstrate that the chirp control technique is effective even for a high bit rate optical signal up to 10 Gb/s, when the carrier lifetime is expedited by optical pumping     

Development of correlation-based clustering method and its application to software sensing

The individuality of production devices should be taken into account when soft-sensors are designed for parallelized devices. Since it is expressed as differences of the correlation among measured variables, it is useful to cluster samples on the basis of the correlation among variables for adopting a multi-model approach. In addition, changes in process characteristics can be coped with in the same way. In the present work, a new clustering method, referred to as NC-spectral clustering, is proposed by integrating the nearest correlation (NC) method and spectral clustering. Spectral clustering is a graph partitioning method that can be used for sample classification when an affinity matrix of a weighted graph is given. The NC method can detect samples that are similar to the query from the viewpoint of the correlation without a teacher signal. In the proposed method, the NC method is used for constructing the weighted graph that expresses the correlation-based similarities between samples and the constructed graph is partitioned by using spectral clustering. In addition, a new soft-sensor design method is proposed on the basis of the proposed NC-spectral clustering. The usefulness of the proposed methods is demonstrated through a numerical example and a case study of parallelized batch processes. The performance of the proposed correlation-based method is better than that of the conventional distance-based methods.     

Adsorption of REEs from Aqueous Solution by EDTA-Chitosan Modified with Zeolite Imidazole Framework (ZIF-8)

Chitosan (CS) modified with ethylenediamine tetraacetic acid (EDTA) was further modified with the zeolite imidazole framework (ZIF-8) by in situ growth method and was employed as adsorbent for the removal of rare-earth elements (REEs). The material (EDTA–CS@ZIF-8) and ZIF-8 and CS were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM), and nitrogen adsorption/desorption experiments (N₂- Brunauer–Emmet–Teller (BET)). The effects of adsorbent dosage, temperature, the pH of the aqueous solution, contact time on the adsorption of REEs (La(III), Eu(III), and Yb(III)) by EDTA–CS@ZIF-8 were studied. Typical adsorption isotherms (Langmuir, Freundlich, and Dubinin–Radushkevich (D-R)) were determined for the adsorption process, and the maximal adsorption capacity was estimated as 256.4 mg g⁻¹ for La(III), 270.3 mg g⁻¹ for Eu(III), and 294.1 mg g⁻¹ for Yb(III). The adsorption kinetics results were consistent with the pseudo-second-order equation, indicating that the adsorption process was mainly chemical adsorption. The influence of competing ions on REE adsorption was also investigated. After multiple cycles of adsorption/desorption behavior, EDTA–CS@ZIF-8 still maintained high adsorption capacity for REEs. As a result, EDTA–CS@ZIF-8 possessed good adsorption properties such as stability and reusability, which have potential application in wastewater treatment.     

Preliminary comparison of respiratory signals using acceleration on neck and humidity in exhaled air

Microsystem Technologies - A microelectromechanical system is recently used for measurements of vital signs. Although the neck is regarded as an alternate observatory location of heartbeats, there...     

The Effect of Antiozonants on the Reaction of Dyes with Ozone. 2 — Contribution of Antiozonant to the Performance of a ZnO-Rose Bengal Photosensor During Electrophotography

The breakdown of zinc oxide-Rose Bengal photosensor has been found to be caused by the fading of Rose Bengal and degradation of resin by ozone and singlet oxygen. When 4, 4′-methyiene-bis(2, 6-di-t-butyiphenol), an antiozonant, was added the life of the photosensor was extended from 500 to 2000 charge-light-decay cycles.     

Endlessly rotatable fractional-wave devices for single-mode-fibre optics

Endlessly rotatable fractional-wave devices for polarisation control in single-mode fibres are described which utilise stress birefringence induced by fibre bending, and are free from fibre twist by rotating the fibre around its own axis. Experiments confirm that these devices rotate endlessly and have small hysteresis.     

Impaired motor coordination correlates with persistent multiple climbing fiber innervation in PKC gamma mutant mice

It is generally believed that a smooth execution of a compound movement, or motor coordination, requires learning of component movements as well as experience-based refinement of the motor program as a whole. PKC gamma mutant mice display impaired motor coordination but intact eyeblink conditioning, a form of component movement learning. Cerebellar long-term depression, a putative cellular mechanism for component motor learning, is also unimpaired. Thus, PKC gamma mutant mice are defective in refinement of the motor program. In the accompanying paper, we demonstrate that innervation of multiple climbing fibers onto Purkinje cells persists in adulthood in these mutant mice. We propose that this defective elimination of surplus climbing fibers underlies motor discoordination.