Characterization of raw materials and manufactured binderless particleboard from oil palm biomass

The objective of this study was to examine the extractive, holocellulose, alpha cellulose, lignin, starch, and sugar contents of oil palm biomass and to evaluate its suitability in binderless particleboard production. In this study, bark, leaves, fronds, mid-parts and core-parts of the trunks were used to produce experimental binderless particleboard panels. Binderless particleboard panels were made with a target density of 0.80 g/cm³ at a temperature of 180 °C and a pressure of 12 MPa in a computer controlled hot press. The modulus of rupture, the internal bond strength, the thickness swelling and the water absorption of the panels were evaluated. Fourier transform infrared spectroscopy and field emission scanning electron microscopy were used to characterize the properties of the raw materials and the manufactured panels. The chemical composition of the oil palm biomass consisted of high holocellulose, lignin, starch and sugar contents that have been found to aid in the production of binderless particleboard. The core-part of the trunk contained the highest amount of starch and total sugar. Samples made from the core-parts and fronds had sufficient modulus of rupture and internal bond strength to meet the Japanese Industrial Standard. The internal bond strength of the mid-part panels also met the standard. However, binderless board prepared from bark and leaves showed poor modulus of rupture and internal bond strength. Samples from the core-parts had the lowest thickness swell and water absorption but did not meet the above standard. The Fourier transform infrared spectroscopy spectra did not show any substantial difference between the raw materials and the manufactured panels. Field emission scanning electron microscopy indicated that the compressed cells varied between raw material types and showed the presence of compressed cells with some starch granules that facilitated adhesion. Based on the findings of this study, oil palm has the potential to be used to manufacture binderless panel products, and further study is required to improve its dimensional stability.     

Synthesis and electrical conductivity of La0.6Sr0.4Ru1−xMgxO3−δ (x = 0–0.6) perovskite solid solution

Sr and Mg were doped at La- and Ru-sites of perovskite oxide LaRuO₃, respectively, to enhance electrical conductivity and catalytic property as a cathode material for a low temperature solid oxide fuel cell. Crystal structure and particle morphology of La_0.6Sr_0.4Ru_1?xMg_xO_3?δ powders (shorten as LSRM) and electrical conductivity of sintered LSRM were studied. LSRM powders (x = 0–0.6) were prepared by co-precipitation method using metal nitrate solutions and ammonium carbonate solution. The freeze-dried powders were heated at 1273 K in air to form LSRM solid solution of orthorhombic structure. The true densities and particle sizes of LSRM solid solution, where valence of Ru was estimated to be 3+, decreased with increasing Mg content. The electrical conductivity of LSRM at x = 0–0.3 was almost independent of temperature and was in a range of 19–360 S cm^?1 at 1073 K. Hole conduction contributed to the high electrical conductivities. LSRM at x = 0.4 and 0.5 was a mixed conductor of oxide ions and holes, and showed a conductivity of 11 S cm^?1 at 1073 K in air. This conductivity decreased at a lower oxygen pressure and reached a constant value below 10 Pa of oxygen pressure.     

Revealing the formation mechanism of granules by drying simulation of slurry droplet

The formation mechanism of granules in spray drying process was investigated by DEM-CIP method simulation coupled with a new binder segregation model. To confirm the validity of proposed binder segregation model, experiment on drying of aqueous slurry containing fine particles and binder was performed. The experimental concentration distribution of binder in a dried powder bed agreed well with the simulated one and this result shows that the proposed segregation model is valid to represent segregation phenomenon in the dried granule. Spherical hollow granules were formed with increasing of binder concentration, and the granules were depressed in higher concentration of binder. When the binder concentration in the surface region of a slurry droplet increased during drying, a crust of granule was formed because particle migration was hindered by high fluid viscosity. For the rigid crust layer, granules were hollow. When the crust layer was formed early in drying and its thickness was thin, granule surface partially collapsed inward, whereas the granule resulted in depression granules.     

Numerical study on flash‐boiling spray of multicomponent fuel

Flash‐boiling occurs when a fuel is injected into a combustion chamber where the ambient pressure is lower than the saturation pressure of the fuel. It has been known that flashing is a favorable mechanism for atomizing liquid fuels. On the other hand, alternative fuels, such as gaseous fuels and oxygenated fuels, are used to achieve low exhaust emissions in recent years. In general, most of these alternative fuels have high volatility and flash‐boiling takes place easily in the fuel spray when injected into the combustion chamber of an internal combustion engine under high pressure. In addition the multicomponent mixture of high‐ and low‐volatility fuels has been proposed in the previous study in order to control the spray and combustion processes in an internal combustion engine. It was found that the multicomponent fuel produces flash‐boiling with an increase in the initial fuel temperature. Therefore, it is important to investigate these flash‐boiling processes in fuel spray. In the present study, the submodels of a flash‐boiling spray are constructed. These submodels consider the bubble nucleation, growth, and disruption in the nozzle orifice and injected fuel droplets. The model is implemented in KIVA3V and the spray characteristics of multicomponent fuel with and without flashing are numerically investigated. In addition, these numerical results are compared with experimental data obtained in the previous study using a constant volume vessel. The flashing spray characteristics from numerical simulation qualitatively show good agreement with the experimental results. In particular, it is confirmed from both the numerical and experimental data that flash‐boiling effectively accelerates the atomization and vaporization of fuel droplets. This means that a lean homogeneous mixture can be quickly formed using flash‐boiling in the combustion chamber. © 2006 Wiley Periodicals, Inc. Heat Trans Asian Res, 35(5): 369–385, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/htj.20117     

Emulsion culture: a miniaturized library screening system based on micro-droplets in an emulsified medium

A typical library screen in directed evolution primarily requires physical separation of the clones on agar plates followed by detection of clones with improved properties; using this method only limited numbers of clones relative to the number of potential variations can be assessed. In particular, screening for a secretory enzyme is difficult to perform at high clone density, because of diffusion of the signal or unfavorable utilization of the reaction product by neighboring clones. In this study, we have developed a novel method of enrichment culture: “Emulsion Culture”, i.e., segregated replication of clones in an emulsified culture medium. Clones expressing enzyme-variants are separately distributed to small (up to 50 μm in diameter), segregated compartments composed of a droplet of medium to form several tens of millions of microcolonies in a milliliter of medium, which allows a miniaturized, in-bulk screening of clones. We applied this culture method to yeast clones expressing secretory beta-galactosidase to analyze the enrichment factor achieved. A high-density screen for a signal peptide sequence that maximizes extracellular production of the enzyme was also performed to demonstrate the practicability of this culture method. In addition, micro-channel emulsification was tested as a method of forming uniformly-sized compartments in the emulsion.     

Effect of Tween 80 on the growth, lipid accumulation and fatty acid composition of Thraustochytrium aureum ATCC 34304

Thraustochytrium aureum ATCC 34304 was grown in the presence and absence of polyoxyethylene sorbitan monooleate (Tween 80). The aim of this work was to obtain basic knowledge about the effect of Tween 80 on growth, lipid accumulation and fatty acid composition in T. aureum. The addition of Tween 80 to a culture medium significantly enhanced the growth of T. aureum, and the biomass increased with an increase of Tween 80 content. Total lipid content and total fatty acid content were significantly higher in 1.0% Tween 80 in comparison with the control (absence of Tween 80). The fatty acid profile showed that the content of C18:1n-9 (oleic acid) significantly increased as a result of the addition of Tween 80. These results indicated that part of the Tween 80 added to the medium was utilized as a carbon source or that the oleate included in Tween 80 was directly incorporated into T. aureum cells as a fatty acid. Neither the DHA content nor the percentage of DHA did not change in spite of the addition of Tween 80. However, the DHA yield significantly increased because the biomass increased due to the addition of Tween 80.     

9-oxo-10(E),12(E)-Octadecadienoic acid derived from tomato is a potent PPAR α agonist to decrease triglyceride accumulation in mouse primary hepatocytes

Scope: Tomato is one of the most common crops worldwide and contains many beneficial compounds that improve abnormalities of lipid metabolism. However, the molecular mechanism underlying the effect of tomato on lipid metabolism is unclear. It has been commonly accepted that peroxisome proliferator‐activated receptor α (PPARα) is one of the most important targets for ameliorating abnormalities of lipid metabolism. Therefore, we focused on the activation of PPARα and attempted to detect active compounds activating PPARα in tomato. Methods and results: To identify such active compounds, we screened fractions of tomato extracts using PPARα luciferase reporter assay. One fraction, rechromatographed‐fraction eluted in 57 min (RF57), significantly increased PPARα reporter activity, in which a single compound is detected by LC/MS analysis. On the basis of LC/MS and NMR analyses, we determined the chemical structure of the active compound in RF57 as 9‐oxo‐10(E),12(E)‐octadecadienoic acid (9‐oxo‐ODA). The RF57 fraction significantly increased the mRNA expression levels of PPARα target genes involved in fatty acid oxidation and O₂ consumption in mouse primary hepatocytes. Furthermore, RF57 inhibited cellular triglyceride accumulation in the hepatocytes. Conclusion: These findings suggest that tomatoes containing 9‐oxo‐ODA that acts on PPARα are valuable for ameliorating abnormalities of lipid metabolism.     

Performance analysis of slotted ALOHA and network coding for single-relay multi-user wireless networks

Deployment of wireless relay nodes can enhance system capacity, extend wireless service coverage, and reduce energy consumption in wireless networks. Network coding enables us to mix two or more packets into a single coded packet at relay nodes and improve performances in wireless relay networks. In this paper, we succeed in developing analytical models of the throughput and delay on slotted ALOHA (S-ALOHA) and S-ALOHA with network coding (S-ALOHA/NC) for single-relay multi-user wireless networks with bidirectional data flows. The analytical models involve effects of queue saturation and unsaturation at the relay node. The throughput and delay for each user node can be extracted from the total throughput and delay by using the analytical models. One can formulate various optimization problems on traffic control in order to maximize the throughput, minimize the delay, or achieve fairness of the throughput or the delay. In particular, we clarify that the total throughput is enhanced in the S-ALOHA/NC protocol on condition that the transmission probability at the relay node is set at the value on the boundary between queue saturation and unsaturation. Our analysis provides achievable regions in throughput on two directional data flows at the relay node for both the S-ALOHA and S-ALOHA/NC protocols. As a result, we show that the achievable region in throughput can be enhanced by using network coding and traffic control.     

Molecular Stacking Induced by Intermolecular C–H···N Hydrogen Bonds Leading to High Carrier Mobility in Vacuum‐Deposited Organic Films

Simple bottom‐up fabrication processes for molecular self‐assembly have been developed for the construction of higher‐order structures using organic materials, and have contributed to maximization of the potential of organic materials in chemical and bioengineering. However, their application to organic thin‐film devices such as organic light‐emitting diodes have not been widely considered because simple fabrication of a solid film containing an internal self‐assembly structure has been regarded as difficult. Here it is shown that the intermolecular C–H···N hydrogen bonds can be simply formed even in vacuum‐deposited organic films having flat interfaces. By designing the molecules containing pyridine rings properly for the intermolecular interaction, one can control the molecular stacking induced by the intermolecular hydrogen bonds. It is also demonstrated that the molecular stacking contributes to the high carrier mobility of the film. These findings provide new guidelines to improve the performance of organic optoelectronic devices and open up the possibilities for further development of organic devices with higher‐order structures.