Effect of in-flight particle behavior on the morphology of flame sprayed Er2O3 splats

The morphology and microstructure of splats impact the comprehensive capability of a new coating methodology called chelate flame spraying (CFS). This study addresses the quantitative characterization of the spread morphologies of flame sprayed Er₂O₃ splats directly deposited under different spray conditions on aluminum alloy substrates with a mirror finish. The influence of the in-flight particle temperature and velocity, carrier gas type, and carrier gas ratio on the solidification mechanism of molten droplets was investigated. Image analysis methods were employed to identify single splats from the morphology observed with field-emission scanning electron microscopy (FE-SEM). In addition, Er₂O₃ films were synthesized on an Al–Mg alloy (A5052) substrate using N₂ or O₂ as the carrier gas. When O₂ was used as the carrier gas, 109-μm-thick films were deposited on the A5052 substrate. The cross-sectional porosity of the films was 3.8%. In contrast, films with 101-μm thickness were synthesized on the A5052 substrate when N₂ was used as the carrier gas. The cross-sectional porosity of these films was 13.8%. The results showed that the carrier gas type (N₂) and carrier gas ratio had a significant effect on the flattening behavior of the molten droplets. A spraying method combined with multidimensional modes is proposed to control the morphology of the splats.     

Effect of superfine particles of alumina incorporated in the cavities of mordenite in enhancing selectivity

Alumina has been incorporated in the cavities of mordenite by the hydrolysis of Al³⁺ ions in the cavities with moist ammonia gas, following calcination at 450°C. The incorporation of the superfine particles of alumina into the cavities of the mordenite is assessed on the basis of the data of MAS ²⁷Al NMR measurements, X-ray powder diffraction and the amount of saturated adsorption of nitrogen for FAL/MZ. The acid properties, assessed using NH₃ TPD and FTIR studies, show the presence of Brønsted and Lewis acid sites on the catalyst, and an increase in acidic sites on incorporating alumina. The dehydrogenation selectivities of FAL/MZ, Al³⁺/MZ, H⁺/MZ, and Na⁺/MZ have been investigated. Brønsted acid sites largely enhance the ring-cleavage, whereas this incorporation of superfine particles of alumina significantly suppresses the ring-cleavage. Therefore, the incorporation of the superfine particles increases remarkably in the cyclohexene selectivity.     

Microstructure and hydrogen desorption characteristics of hydrogenated ScH2–MBn (M = Mg and Ca) systems synthesized by mechanical milling

The mixtures of scandium hydride ScH₂ and metal boride MB_n, which is MgB₂ or CaB₆, were hydrogenated by mechanical milling under hydrogen pressure at room temperature. ScH₂–MgB₂ and ScH₂–CaB₆ desorbed 3.4 and 2.3 mass% of H₂, respectively, with peaks below 300 °C. The results of synchrotron radiation X-ray powder diffraction and X-ray absorption spectroscopy at the Sc K-edge indicated that ScB₂ was produced by milling. Fourier-transform infrared spectroscopy suggested that hydrogen was stored as B–H bonds in the as-milled samples. Nuclear magnetic resonance spectroscopy clarified the presence of metal borohydrides M(BH₄)₂ (M = Mg and Ca) in the as-milled ScH₂–MB_n mixtures. These results indicate that M(BH₄)₂ is synthesized by milling the ScH₂–MB_n mixtures under hydrogen pressure at room temperature, and hydrogen was desorbed from M(BH₄)₂. The by-products of M(BH₄)₂ are MgH₂ in the M = Mg case, which was observed by transmission electron microscopy, and ScB₂ in both cases.     

Estimating Land Use Impacts on Regional Scale Urban Water Balance and Groundwater Recharge

Anthropogenic activities have exerted increasingly large-scale influences on terrestrial ecological systems from the past century, primarily through agriculture; however, the impact of such changes on the hydrologic cycle is poorly understood. As one of the important land use (LU) in the coastal Dogo Plain of the Seto Inland Sea, Japan, paddy fields have been decreasing with the increase in urbanization in recent decades. As the main source of water in the Dogo Plain, groundwater plays an important role in providing people with fresh water and contributing to stream base flow. The purpose of this study is to analyze the water resource and evaluate the effect of LU change on groundwater table fluctuation in this coastal plain. Firstly, the observations of groundwater table and the investigation of water balance were carried out in this alluvial plain. Then, a distributed four-block three-layer water balance model was employed to analyze the groundwater table fluctuation with response to the change of paddy field area. Moreover, the role of paddy field in recharging groundwater in the basin has been clarified. Results show that groundwater table depends not only on rainfall and discharge from rivers, but also on irrigation water and topology of the study area. The net groundwater recharge was positive in irrigation periods whereas that in non-irrigation periods was nearly equal to zero or negative. The results of this study would be helpful to the urban development policy and land use planning decision.     

Preparation of detergent-lipase complexes utilizing water-soluble amphiphiles in single aqueous phase and catalysis of transesterifications in homogeneous organic solvents

A novel method of preparing detergent-enzyme complexes that can be employed in organic media was developed utilizing newly synthesized water-soluble nonionic gemini-type detergents, N,N-bis(3-D-gluconamidopropyl)-3-(dialkyl-L-glutamatecarbonyl)propanamides (BIG2CnCA: n = 10,12,14,16,18) and N,N-bis(3-D-lactonamidopropyl)-3-(dialkyl-L-glutamatecarbonyl)propanamides (BIL2CnCA: n = 16,18), and nonionic twin-headed detergents, N,N-bis(3-D-gluconamidopropyl)alkanamides (BIG1Cn: n = 12,14,16,18,delta9). This method simply entails mixing a selected enzyme with an appropriate detergent in an aqueous solution followed by lyophilization, and it offers the advantages of enhanced enzymatic activity in organic solvents and eliminates both enzyme loss and the necessity for an organic solvent in the preparation stage. Using various modified lipases originating from Aspergillus niger (Lipase A), Candida rugosa (Lipase C), Pseudomonas cepacia (Lipase P), and porcine pancreas (PPL), prepared using the novel method and detergents, including conventional synthesized nonionic detergents such as dialkyl N-D-glucona-L-glutamates (2CnGE: n = 12,18delta9) and octanoyl-N-methylglucamide (MEGA-8), enantioselective transesterifications of 6-methyl-5-hepten-2-ol (sulcatol) and 2,2-dimethyl-1,3-dioxolane-4-methanol (solketal) with a vinyl or isopropenyl carboxylate were carried out in an organic solvent. The modified lipase activity was influenced by both the lipases and the structure of the detergents. The value for the hydrophile-lipophile balance (HLB) of the detergent provided a means of correlating the structure and the obtained modified lipase activity. For detergents of the same class with a HLB value of approximately 9 and 12, the highest activity was obtained for Lipase A and Lipase P, and Lipase C and PPL, respectively. Among detergents of the same HLB value tested, the gemini-type detergents possessing the most bulky head and tail were most effective as a modifier for lipases of all types. The preparation and reaction conditions for these novel gemini-type detergent-modified lipases were optimized using BIG2C12CA (HLB = 9.4) by studying the effect of the detergent/lipase ratio and the nature of organic solvents on the complex formation. The high enzymatic activities of the BIG2C12CA-modified lipases were independent of the solubility of the lipases in organic solvents, unlike in the case of 2CnGE-modified lipases prepared using the conventional suspension system.     

Specific heat anomaly of nonstoichiometric U4O9−y

A λ-type specific heat anomaly of U₄O_9?y, which occurs slightly above room temperature, was measured for the samples with different O/U ratios. The transition temperatures obtained from the peak of λ-type specific heat anomaly are in fairly good agreement with the data by X-ray diffraction and electrical conductivity measurements. The entropy increment for the transition was obtained to be 0.46 e.u. for UO_2.250, 0.56 e.u. for UO_2.240 and 0.70 e.u. for UO_2.228, depending on O/U ratio. On the basis of the entropy change with O/U ratio, the mechanism of the phase transition is discussed. The entropy change due to the phase transition is mainly divided into two terms: one is due to the order-disorder rearrangement of U(IV) and U(V) ions,the other is associated with the displacement of oxygens ions. The former term is estimated to be rather smaller than the entropy change calculated by the Bragg-Williams approximation, and the latter is calculated using the X-ray diffraction data with the assumption of the Willis model.     

Effect of packed structure on flow behaviour in a trickle bed biofilter

The effects of operation conditions on the flow behaviour in gas–liquid countercurrent trickle bed biofilter were experimentally examined. In order to prevent gas channelling in the biofilter, packings with a relatively large void fraction, which have a role to maintain a high void fraction in the bed, were added. The gas and liquid velocities of the packed structure and the packings were changed, and the residence time distributions (RTDs) of the gas and liquid were measured. It was found that the addition of void supporters was very effective in the suppression of gas channelling.     

A behavioral model for optically powered OCT endoscope with a micro electrostatic vertical‐comb optical scanner

This paper presents a novel device architecture for optically actuated microelectromechanical systems (MEMS) endoscopes for optical coherence tomography (OCT) measurement. A 10‐mW infrared light beam at a wavelength of 1.5 µm is transferred through the single‐mode fiber to provide a scanning MEMS mirror with the drive voltage (maximum 11 V) by exciting a photovoltaic cell, while also providing with a secondary light beam at a wavelength of 1.3 µm for the OCT measurement. An electrostatic vertical comb‐drive optical scanner (1.5 mm × 2.0 mm × 0.5 mm) has been developed by using the deep reactive ion etching (DRIE) of a silicon‐on‐insulator (SOI) wafer. The design of the scanner module is discussed, along with the experimental results of electrostatic operation. An equivalent circuit model for the optical scanner is developed to explain the behavior of the optically powered actuation mechanism, including the hysteresis loop in the frequency response and the voltage dependence of oscillating angle (mechanical peak ±3.2°/7 V around the resonance frequency of 250 Hz). OCT measurement of a tissue is demonstrated to reconstruct the cross‐sectional image of a fingerprint at a resolution of lateral 40 µm × vertical 8 µm and penetration depth of 2.5 mm. © 2014 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

Effects of repetitive transcranial magnetic stimulation and transcranial direct current stimulation on posterior alpha wave

Because of the unclear conclusion of the repetitive transcranial magnetic stimulation (rTMS) and transcranial direct current stimulation (tDCS) effects on the posterior electroencephalogram (EEG) alpha wave, this study is aimed at investigating these unclear effects. Transcranial stimulation effects are observed by analyzing a measured EEG at the occipital area between prestimulation and the poststimulation. The EEG alpha power and alpha coherence are calculated and analyzed in terms of the ratio between eyes closed and eyes open periods. The results reveal that alpha power ratio at the individual alpha frequency (IAF) significantly increases after the 1‐Hz rTMS and cathodal tDCS and slightly decreases after the anodal tDCS compared to the control and the sham conditions. The results also show that there is a significant difference between the inhibited and excited conditions. Similarities are observed in the patterns of the alpha coherence ratio and alpha power changes. The alpha coherence increases in the rTMS and cathodal tDCS conditions, and decreases in the anodal tDCS condition but these effects occur only when comparing across the hemispheres (O1–O2 and P3–P4). It can be summarized that the EEG alpha wave can be influenced by the transcranial stimulations. The rTMS and cathodal tDCS seem to facilitate the alpha activity and the anodal tDCS inhibits it. © 2013 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

Experimental verification of the effect of a voltage‐detection‐based shunt active filter for harmonic damping throughout a power distribution line

This paper is focused on a voltage‐detection‐based shunt active filter for installation on a power distribution system. A main objective of the active filter is to achieve damping of harmonic propagation coming from series/parallel resonance between capacitors for power factor correction and line inductors in the distribution system. The active filter installed at the end terminal of a distribution feeder is controlled in such a way as to present infinite impedance to the external circuit for the fundamental frequency, and to exhibit low resistance for harmonic frequencies. As a result, the active filter acts as a damping resistor for the harmonic propagation, like a 50‐Ω terminator installed at the end of a signal transmission line. It is verified by experiment that the active filter intended for harmonic termination has the capability of harmonic damping throughout the distribution feeder. © 2000 Scripta Technica, Electr Eng Jpn, 133(2): 1–10, 2000