Pyrolysis of Poly(isopropyliminoalane) to Aluminum Nitride

The pyrolysis processes of poly(isopropyliminoalane) ((HAlN ⁱ Pr) _n ) were investigated, using mass spectrometry to analyze the gases and infrared spectroscopy to analyze the residual solids. The major mass loss (in the temperature range of 240°–540°C) consisted of two different pyrolysis stages. At the first stage (240°–320°C), (HAlN ⁱ Pr)₆ was detected continuously as a gas, and the precursor was converted to a cross-linked structure. A polymerization mechanism without a release of organic compounds has been proposed, and the formation of (HAlN ⁱ Pr)₆ during polymerization (besides its evaporation) has been suggested. The second stage (320°–560°C) involved the formation of various organic compounds, and radical processes for their formation were proposed.     

Evaluation of Strain Field Around Impacted Particles by Applying Electron Moiré Method

Recently, the thermal-spray community has focused considerable attention on cold-spray and warm-spray techniques, in which the temperatures of sprayed particles are kept below their melting point and adhesion occurs based on the impact phenomenon between a solid particle and a substrate. The mechanisms of adhesion are still unclear, but the degree of the mechanical deformation at the interface is considered to be a key factor influencing this mechanism. However, it is very difficult to directly measure the strain at the interface. Instead, in this work, the strain fields on a substrate around an impacted particle sprayed by warm-spray deposition were measured by applying electron Moiré method, and compared with numerical simulation results. This article is an invited paper selected from presentations at the 2007 International Thermal Spray Conference and has been expanded from the original presentation. It is simultaneously published in Global Coating Solutions, Proceedings of the 2007 International Thermal Spray Conference, Beijing, China, May 14-16, 2007, Basil R. Marple, Margaret M. Hyland, Yuk-Chiu Lau, Chang-Jiu Li, Rogerio S. Lima, and Ghislain Montavon, Ed., ASM International, Materials Park, OH, 2007.     

Hepatoprotective effect of the endothelin receptor antagonist TAK-044 against ischemia-reperfusion injury in the canine liver

The present study was designed to investigate if TAK-044, a novel endothelin (ET) ETA/ETB receptor antagonist, inhibits ischemia-reperfusion liver injury. The initial study showed the presence of both ETA and ETB receptors in canine hepatic membrane fractions using the specific binding assay of labeled ET-1 with ET isomers and TAK-044. The nonselective ETA/ETB receptor antagonist TAK-044 inhibited the specific binding of ET-1 to the receptors in a concentration-dependent manner. In subsequent studies using a canine 70% partial liver ischemic model (60 minutes), we found that an intravenous injection of TAK-044 (3 mg/kg) before ischemia significantly inhibited the release of serum liver enzymes (aspartate transaminase, alanine transaminase, mitochondrial glutamic oxaloacetic transaminase, and an increase of indocyanine green retention rate after reperfusion, compared with the control group. Elevation of the portal venous pressure was also suppressed significantly during the portal triad occlusion, and a rapid restoration of oxygen pressure in the liver tissue after reperfusion was observed in the TAK-044-treated group. Morphometric analysis revealed that the hepatocyte swelling and sinusoidal contraction 1 hour after reperfusion were significantly less severe in the treated group than in the control group. The sludging of erythrocytes in the sinusoidal lumens was also minimal in the treated group. In conclusion, the significant suppression of hepatic microcirculatory disturbance and tissue injury after ischemia-reperfusion were shown in the TAK-044-treated group. This finding indicates that the pretreatment of TAK-044 is useful as a hepatoprotective agent against ischemia-reperfusion injury, which is otherwise produced by a pathway involving ET-1.     

Development of WC-Co Coatings Deposited by Warm Spray Process

The high-velocity oxy-fuel (HVOF) process is commonly used to deposit WC-Co coatings. There are some problems with this process; especially the decomposition and decarburization of WC during spraying make a coating brittle. To suppress such degradation, the warm spray (WS) process was applied to deposit WC-Co coatings, which is capable of controlling the flame temperature in the range of 500-2000 °C. The microstructure and phases of the deposited coatings were characterized by using SEM and XRD, and the mechanical properties such as hardness, fracture toughness, and wear properties were also investigated. WS process successfully suppressed the formation of the detrimental phases such as W₂C and W, which are usually observed in HVOF coatings. The WS coatings showed the similar trend of the hardness variation for Co content with a sintered bulk material. Improvement of toughness and wear behavior was also observed in WS coatings.     

A laboratory-scale test of anaerobic digestion and methane production after phosphorus recovery from waste activated sludge

In enhanced biological phosphorus removal (EBPR) processes, activated sludge microorganisms accumulate large quantities of polyphosphate (polyP) intracellularly. We previously discovered that nearly all of polyP could be released from waste activated sludge simply by heating it at 70 degrees C for about 1 h. We also demonstrated that this simple method was applicable to phosphorus (P) recovery from waste activated sludge in a pilot plant-scale EBPR process. In the present study, we evaluated the effect of this sludge processing (heat treatment followed by calcium phosphate precipitation) on anaerobic digestion in laboratory-scale experiments. The results suggested that the sludge processing for P recovery could improve digestive efficiency and methane productivity at both mesophilic (37 degrees C) and thermophilic (53 degrees C) temperatures. In addition, heat-treated waste sludge released far less P into the digested sludge liquor than did untreated waste sludge. It is likely that the P recovery step prior to anaerobic digestion has a potential advantage for controlling struvite (magnesium ammonium phosphate) deposit problems in sludge handling processes.     

Error analysis of drill point geometry inspection using radial-view silhouette images

The conical ground drill point geometry can be described by five parameters, which are measured with the simple inspection method using radial-view silhouette images. This paper deals with error analysis of the inspection method. Different types of errors may occur while taking radial-view silhouette images of the drill point geometry. All possible setup errors have been considered and deviations from the true values of the geometrical parameters have been calculated. The sensitivities of the geometrical parameters and common angular parameters of the drill with the errors have been analyzed to develop a practical apparatus of the inspection system.     

Steroidal saponins from the rhizomes of Hosta sieboldii and their cytostatic activity on HL-60 cells

A total of eighteen steroidal saponins were isolated from the rhizomes of Hosta sieboldii, one of which appeared to be the first isolation from a plant source and six to be new compounds. The structures of the new saponins were determined by spectral data and a few chemical transformations to be (25R)-2 alpha, 3 beta-dihydroxy-5 alpha-spirostan-12-one (manogenin) 3-O-?O-beta-D-glucopyranosyl-(1-->2)-O-beta-D-glucopyranosyl -(1-->4)-beta-D-galactopyranoside?, (25R)-2 alpha,3 beta-dihydroxy-5 alpha-spirost-9-en-12-one (9,11-dehydromanogenin) 3-O-?O-beta-D-glucopyranosyl-(1-->2)-O-beta-D- glucopyranosyl-(1-->4)-beta-D-galactopyranoside?, 9,11-dehydromanogenin 3-O-?O-beta-D-glucopyranosyl-(1-->2)-O-[O-alpha-L- rhamnopyranosyl-(1-->4)-beta-D-xylopyranosyl-(1-->3)]-O-beta-D- glucopyranosyl-(1-->4)-beta-D-galactopyranoside?, (25R)-2 alpha,3 beta-dihydroxy-26-beta-D-glucopyranosyloxy-22-methoxy-5 alpha-furostan-12-one 3-O-?O-beta-D-glucopyranosyl-(1-->2)-O-[beta-D-xylopyranosyl-(1-->3)]-O- beta-D-glucopyranosyl-(1-->4)-beta-D-galactopyranoside?, (25R)-2 alpha, 3 beta-dihydroxy-26-beta-D-glucopyranosyloxy-22-methoxy-5 alpha-furost-9-en-12-one 3-O-?O-beta-D-glucopyranosyl-(1-->2)-O-[beta-D-xylopyranosyl-(1-->3)]-O- beta-D-glucopyranosyl-(1-->4)-beta-D-galactopyranoside? and (25R)-5 alpha-spirostan-2 alpha,3 beta,12 beta-triol 3-O-?O-alpha-L- rhamnopyranosyl-(1-->2)-beta-D-galactopyranoside?, respectively. Cytostatic activity of the isolated saponins on leukaemia HL-60 cells was examined.     

Causes of animal extinction in small irrigation reservoirs in Japan and requirements for future re-establishment

In the past, small irrigation reservoirs were constructed only for rice paddy irrigation in Japan. Many of the watersheds for these irrigation reservoirs were forests. These watersheds have been gradually developed into farmland or housing areas. After World War II, the use of chemical fertilizers, such as ammonium sulphate, became popular in upland fields in Japan. As a result, there are high concentrations of nitrates in groundwater and spring water under upland fields. Hence, irrigation reservoirs that collect water from these watersheds have been polluted by nitrates. High nitrates concentrations in irrigation reservoirs have been found where the watershed is located close to tea yards. However, there has been minimal research into these reservoirs in the fields of limnology and agricultural engineering. We have therefore tried to verify the water‐quality characteristics in irrigation reservoirs from the point of view of water‐quality conservation. In the process of the investigation, we encountered a quite significant reservoir called the Tanno Reservoir that has not seen any forms of life. We examined the causes of this lack of life, as well as measures that could be taken for the remediation of such a reservoir. This paper discusses and clarifies the results of these studies.     

Lattice misorientation at domain boundaries in β-Ga2O3 single-crystal substrates observed via synchrotron radiation X-ray diffraction imaging and X-ray reticulography

To evaluate the lattice misorientation at domain boundaries (DBs) in β-Ga₂O₃, we performed X-ray diffraction imaging (XRDI), X-ray reticulography (XRR), and X-ray topography (XRT) using a synchrotron radiation light source. Four reciprocal lattice vectors ( g -vectors) were applied, and the DBs showed different visibilities in the XRDI maps depending on the g -vector. By analyzing possible characteristics of the misorientation, the XRDI results suggested that the DB being investigated was associated with a misorientation on the ($\overline{10}05$) plane and contained twist and tilt components. The apparent peak change in XRDI caused by the two components was calculated. We further succeeded in separating the tilt and twist components using XRR images in conjunction with simulation. Dislocation arrays at the DBs were observed using XRT, and the average distance between the dislocations in the array was consistent with the misorientation obtained using XRDI and XRR. The distribution of DBs across a wide area was acquired by a combination of XRR images recorded on a charge-coupled device camera and X-ray films. The fringe-patterned XRR on X-ray films provided a powerful and nondestructive tool to characterize DBs distributed across a large-diameter wafer with an angular resolution on the order of several arc sec (low 10⁻⁵ rad).     

Improvement in output power of vibration generators based on piezoelectric elements by using internal capacitor cancel control rectifier

Recently, energy harvesting has attracted increasing attention. The present study focuses on vibration generators based on piezoelectric elements by proposing an internal capacitor cancel control (ICCC) rectifier to improve the output power. The proposed rectifier cancels the internal capacitor to improve the output power while retaining the maximum output power. Accordingly, this paper experimentally demonstrates the improvement in output power by using the ICCC rectifier compared to conventional circuits and the previous proposed circuit.