Hydrocarbon chain distribution of ether phospholipids of the ascidianHalocynthia roretzi and the sea urchinStrongylocentrotus intermedius

The contents and compositions of the 1-O-alk-1′-enyl-2-acyl, 1-O-alkyl-2-acyl, and 1,2-diacyl glycerophospholipids in the muscle and viscera of the ascidianHalocynthia roretzi, and of the gonad of the sea urchinStrongylocentrotus intermedius, which are eaten to some extent in Alaska and in Asia, were analyzed by gas-liquid chromatography. 1-O-Alk-1′-enyl-2-acyl glycerophospholipids were found in all of the samples, accounting for 64.4–69.0% of the ethanolamine glycerophospholipid (EPL). By contrast, the levels of the 1-O-Alk-1′-enyl-2-acyl choline glycerophospholipids (CPL) were low (3.1–5.7%). CPL was rich in the 1-O-alkyl-2-acyl subclass amounting to 12.5–23.9% in the ascidian sample. The level of CPL in the sea urchin gonad was extremely high, amounting to 46.1%. The most prominent alkyl chains in thesn-1 position of CPL from the ascidian muscle were 16∶0 (44.6%), 18∶1 (26.5%), and 18∶0 (10.7%), and of CPL from the sea urchin gonad were 18∶0 (36.2%), 16∶0 (33.0%), and 18∶1 (17.8%). Unusually high levels of odd-numbered alkyl chains, e.g., 19∶0 andanteiso 17∶0, were detected in the CPL of all samples. The prominent alkenyl chains of EPL were 18∶0 (69.4%), 16∶0 (10.0%), and 18∶1 (8.54%) (not counting the vinyl double bond) for the sea urchin gonad. Relatively high levels of 20∶1 alkenyl chains were also present. The glycerolsn-2 positions contained high proportions of polyunsaturated fatty acids. Thus, 20∶5n-3 (43.6%) and 22∶6n-3 (20.1%) were most abundant in the alkylacyl CPL from the ascidian muscle and 20∶5n-3 (54.9%) and 20∶4n-6 (30.1%) in alkylacyl CPL from the sea urchin gonad. Despite a possible interconversion of the alkyl and alkenyl chains of each class of the ether phospholipids, they showed few features in common.     

Pyrolysis of sugarcane bagasse pretreated with sulfuric acid

Pyrolysis is a promising technique for the recovery of useful gas, tar, and solid products from biomass waste. However, the low tar yields obtained from lignocellulosic biomass are a significant drawback. To enhance tar yields, sugarcane bagasse, which is the most abundant agricultural waste in Fiji, was pretreated at ambient temperature and atmospheric pressure using various sulfuric acid (H₂SO₄) concentrations. Here, the ether bonds of cellulose, hemicellulose, and lignin were partially hydrolyzed. The pretreated samples were then pyrolyzed at 500 °C, and it was confirmed that H₂SO₄-pretreatment disrupted the bagasse cell structure, with the thermogravimetry and differential thermogravimetry results confirming that decomposition occurred at lower temperatures after pretreatment. In addition, tar yields were significantly enhanced from 5.6 wt% to 13.4 wt% for the untreated and 3 M H₂SO₄-pretreated samples respectively. The main components detected in this tar product were levoglucosan, andcellulose-and hemicellulose-derived products, whose proportions were increased following pretreatment. Thus, our work demonstrates that dilute acid pretreatment enhances tar production from sugarcane bagasse due to the production of shorter chain components via the partial hydrolysis of ether bonds.     

A new control methodology of wind turbine generators for frequency control of power system in isolated island

A wind turbine generator (WTG) system's output is not constant and fluctuates depending on wind conditions. Fluctuating power causes frequency deviations and adverse effects to an isolated power system when large output power from WTG systems is penetrated in the power system. This paper presents an output power control methodology of a WTG for frequency control using a load power estimator. The load power is estimated by a disturbance observer, and the output power command of the WTG is determined according to the estimated load. Besides, the WTG can also be controlled during wind turbulence since the output power command is determined by considering wind conditions. The reduction of the power system frequency deviation by using the WTG can be achieved by the proposed method. The effectiveness of the proposed method is validated by numerical simulations. Copyright © 2010 John Wiley & Sons, Ltd.     

Steam reforming on Ni-samaria-doped ceria cermet anode for practical size solid oxide fuel cell at intermediate temperatures

Direct internal and external reforming operations on Ni-samaria-doped ceria (SDC) anode with the practical size solid oxide fuel cell (SOFC) at intermediate temperatures from 600 to 750 °C are carried out to reveal the reforming activities and the electrochemical activities, being compared with the hydrogen-fueled power generation. The cell performance with direct internal and external steam reforming of methane and their limiting current densities were almost the same irrespective of the progress of reaction in the methane reformate at 700 and 750 °C. The durability test for 5.5 h at 750 °C with direct internal reforming operation confirmed that the cell performance did not deteriorate. The operation temperature of the cell controlled the reforming activities on the anode, and the large size electrode gave rise to high conversion due to the slow space velocity of the steam reforming. Direct internal steam reforming attained sufficient level of conversion for SOFC power generation with methane at 700 and 750 °C on the large Ni-SDC cermet anode.     

Diffusion process of amino acids in polymer supports for solid‐phase peptide synthesis as studied by pulsed‐field‐gradient spin‐echo proton nuclear magnetic resonance

The diffusion coefficient (D) values of tert‐butyloxycarbonyl‐glycine, tert‐butyloxycarbonyl‐L ‐tryptophan, tert‐butyloxycarbonyl‐L ‐phenylalanine (Boc‐Phe), and 9‐fluorenylmethoxycarbonyl‐L ‐phenylalanine in Merrifield polystyrene (MPS) gels, poly(ethylene glycol)‐grafted polystyrene (PEG–PS) gels, and crosslinked ethoxylate acrylate (CLEAR) gels, as used in solid‐phase peptide synthesis, were determined by the pulsed‐field‐gradient spin‐echo ¹H‐NMR method. From these experimental results, it was found that the amino acids in MPS gels, PEG–PS gels, and CLEAR gels with N,N‐dimethylformamide‐d₇ (DMF‐d₇) as a solvent had multidiffusion components within a measurement timescale of 10 ms. The D value of Boc‐Phe in polystyrene gels (1% divinylbenzene crosslinked) with tetrahydrofuran‐d₈ was much larger than that in the same gels with DMF‐d₇. Furthermore, the required time in which an amino acid transferred from a reactive site to a reactive site was estimated, within which the solvents and amino acids in the polymer supports diffused in the swollen beads.© 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 413–421, 2003     

Distributions of hydroperoxide positional isomers generated by oxidation of 1-palmitoyl-2-arachidonoyl-<Emphasis Type="Italic">sn</Emphasis>-glycero-3-phosphocholine in liposomes and in methanol solution

The differences in distribution of geometric isomers of unsaturated PC hydroperoxides generated by free radical oxidation were compared, as corresponding hydroxy analogs, in heterogeneous liposomes and in a homogeneous methanol solution by using HPLC with UV detection due to the presence of conjugated dienes. Identification of fractionated peak components was carried out by GC-MS. When the oxidation of 1-palmitoyl-2-linoleoyl-sn-glycero-3-phosphocholine, PC(16∶0/18∶2), was initiated in liposomes by a hydrophilic azo radical initiator, and in a methanol solution by a hydrophobic azo radical initiator, there was no significant difference in the relative percentages of 1-palmitoyl-2-(9-hydroxy-trans-10,trans-12-octadecadienoyl)-sn-glycero-3-phosphocholine (9-t,t-OH PC) and 1-palmitoyl-2-(13-hydroxy-trans-9,trans-11-octadecadienoyl)-sn-glycero-3-phosphocholine (13-t,t-OH PC) between the PC oxidized in liposomes and in the methanol solution. For the oxidation of 1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphocholine, PC(16∶0/20∶4), the relative percentage of 1-palmitoyl-2-(5-hydroxy-trans-6,cis-8,11,14-eicosatetraenoyl)-sn-glycero-3-phosphocholine (5-OH PC) was significantly higher (P<0.01) than that of 1-palmitoyl-2-(15-hydroxy-cis-5,8,11,trans-13-eicosatetraenoyl)-sn-glycero-3-phosphocholine (15-OH PC) in liposomes. For the homogeneous methanol solution of PC(16∶0/20∶4), the relative percentage of 5-OH PC was close to that of 15-OH PC. For the PC(16∶0/20∶4) oxidized in bulk with added pentamethylchromanol, the individual amount of 15-OH PC, 1-palmitoyl-2-(11-hydroxy-cis-5,8trans-12,cis-14-eicosatetraenoyl)-sn-glycero-3-phosphocholine (11-OH PC), 1-palmitoyl-2-(12-hydroxy-cis-5,8,trans-10,cis-14-eicosatetraenoyl)-sn-glycero-3-phosphocholine (12-OH PC), 1-palmitoyl-2-(8-hydroxy-cis-5,trans-9,cis-11,14-eicosatetraenoyl)-sn-glycero-3-phosphocholine (8-OH PC), 1-palmitoyl-2-(9-hydroxy-cis-5,trans-7,cis-11,14-eicosatetraenoyl)-sn-glycero-3-phosphocholine (9-OH PC), and 5-OH PC were close to each other compared to the corresponding values in liposomes and in methanol solution. The results obtained by gel permeation chromatography of the PC liposomes containing hydrophilic 2,2′-azobis-2-amidinopropane) dihydrochloride (AAPH) suggest that the AAPH added to the liposomes of PC(16∶0/20∶4) was partitioned into the water phase and out of the hydrophobic region of the fatty acyl moieties of the PC. These results confirm that the distance that exists in the bis-allylic carbons of the unsaturated fatty acyl moieties of PC from the interface between the hydrophilic region of PC and the water phases played an important role in influencing hydrogen abstraction to form a symmetrical distribution of hydroperoxide isomers in both the heterogeneous liposomes and the homogeneous methanol solution.     

Sintering Kinetics at Constant Rates of Heating: Effect of Al2O3 on the Initial Sintering Stage of Fine Zirconia Powder

The sinterabilities of fine zirconia powders including 5 mass% Y₂O₃ were investigated, with emphasis on the effect of Al₂O₃ at the initial sintering stage. The shrinkage of powder compact was measured under constant rates of heating (CRH). The powder compact including a small amount of Al₂O₃ increased the densification rate with elevating temperature. The activation energies at the initial stage of sintering were determined by analyzing the densification curves. The activation energy of powder compact including Al₂O₃ was lower than that of a powder compact without Al₂O₃. The diffusion mechanisms at the initial sintering stage were determined using the new analytical equation applied for CRH techniques. This analysis exhibited that Al₂O₃ included in a powder compact changed the diffusion mechanism from grain boundary to volume diffusions (VD). Therefore, it is concluded that the effect of Al₂O₃ enhanced the densification rate because of decrease in the activation energy of VD at the initial sintering stage.     

Output power dispatch control for a wind farm in a small power system

Nowadays, a wind turbine generator (WTG) is required to provide control capabilities as the output power of WTG fluctuates. Under this scenario, this paper proposes an output power control method of a wind farm (WF) connected to a small power system using pitch angle control. In this control approach, the WF output power control is achieved by two control levels: central and local. In the central control, the WF output power command is determined by considering the frequency deviations and wind speeds using a fuzzy function. Then, the local output power commands for each of the WTGs are based on the proposed dispatch control. In the proposed dispatch control, the output commands of each WTG are determined by considering wind conditions for each of the WTGs. The simulation results by using an actual detailed model for the wind power system show the effectiveness of the proposed method. Copyright © 2010 John Wiley & Sons, Ltd.     

Critical issues for the manufacture of the ITER TF coil winding pack

Research and trials by the Japan Atomic Energy Agency (JAEA) focus on the remaining technical issues in the ITER TF coil winding pack (WP) manufacturing process. Specific issues include the feasibility of automatically measuring conductor length during automatic winding with a high degree of accuracy (±0.02%) and a fabrication process to comply with the demanding tolerances (up to 1 mm distortion in flatness and 1.5 mm in-plane shrinkage) of the radial plate (RP) due to cover plate (CP) welding. The authors developed a new technique to measure conductor length very accurately by combining an ordinary encoder and a newly developed optical system. A simulation based on test results of CP welding using a RP mock-up indicates that a flatness of 1 mm is achievable, but the in-plane shrinkage of the RP is approximately 5 mm. One possible solution is to fabricate the RP larger than required to allow for in-plane shrinkage. Another solution is to reduce the thickness or length of the welding. The feasibility of these solutions to most of the major technical issues suggests that it is time for full qualification testing of the fabrication process in a dummy double-pancake trial.