1,721,110 research outputs found
Matrix-stripe-cache-based contiguity transform for fragmented writes in RAID-5
Get PDFGiven that contiguous reads and writes between a cache and a disk outperform fragmented reads and writes, fragmented reads and writes are forcefully transformed into contiguous reads and writes via a proposed matrix-stripe-cache-based contiguity transform (MSC-CT) method which employs a rule of consistency for,data integrity at the block level and a rule of performance that ensures no performance degradation. MSC-CT performs for reads and writes, both of which are produced by write requests from a host as a write request from a host employs reads for parity update and writes to disks in a redundant array of independent disks (RAID)-5. MSC-CT is compatible with existing disk technologies. The proposed implementation in a Linux kernel delivers a peak throughput that is 3.2 times higher than a case without MSC-CT on representative workloads. The results demonstrate that MSC-CT is extremely simple to implement, has low overhead, and is ideally suited for RAID controllers not only for random writes but also for sequential writes in various realistic scenarios
Mixed-Mode Interfacial Fatigue Characteristics of Composite/Metal Interface of Bimaterials
No full textAerobic nitrate respiration by a newly isolated phenol-degrading bacterium, Alcaligenes strain P5
No full textAn aerobic, nitrate-respiring bacterium which can degrade phenol under aerobic conditions was isolated and identified as Alcaligenes sp. Under microaerobic culture, the maximum concentration for phenol to be degraded was 0.29 mM in the presence of nitrate/O-2 but only 0.16 mM in the presence of O-2 alone. Azide (0.1 mM) and Triton X-100 (0.5%) inhibited nitrate reduction and cell growth completely in anoxic culture but had little or no effect on nitrate reduction in aerobic culture
Two-dimensional model for tapered pulse tubes. Part 1: theoretical modeling and net enthalpy flow
No full textA two-dimensional model for the tapered pulse tube was proposed. Linearized conservation equations of mass, momentum and energy of the gas as well as the energy conservation equation of the tube wall were applied to the pulse tube. The mean temperature profile of the gas and the tube wall was obtained by assuming that the outer surface of the pulse tube wall is adiabatic. Axial profile of the mean temperature is linear when the dimensionless frequency is small, but it deviates significantly from linear profile when the dimensionless frequency is large. The effects of operating frequency, taper angle, displacement volume ratio and velocity phase angle between the ends of the pulse tube on net energy flow as well as the effect of the taper angle on the first-order axial velocity and temperature were shown. (C) 2001 Elsevier Science Ltd. All rights reserved
On-Line Coordinate Transformation for 3-Dof Artioulated Rebot : Incremental Unite Computation method
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Crystallization and preliminary X-ray crystallographic analysis of tRNA(m(1)G37)methyltransferase from Haemophilus influenzae
No full textThe enzyme tRNA(m(1)G37)methyltransferase (TrmD) catalyzes the transfer of a methyl group from S-adenosyl-L-methionine (AdoMet) specifically to guanosine at position 37 within a subset of tRNA species in bacteria. The modified guanosine is next to the anticodon and is important for the maintenance of the correct reading frame during translation. TrmD from Haemophilus influenzae with both Nand C-terminal tags was overexpressed in Escherichia coli and crystallized at 297 K using sodium acetate as a precipitant. Native X-ray diffraction data were collected to 1.85 Angstrom resolution. The crystals are rhombohedral, belonging to the space group R32, with unit-cell parameters a = b = 98.05, c = 176.79 Angstrom, alpha = beta = 90, gamma = 120degrees. The presence of one monomer of recombinant TrmD in the crystallographic asymmetric unit gives a V-M of 3.07 Angstrom(3) Da(-1) and a solvent content of 59.9%.
Inhibitory effect of chlorinated guaiacols on methanogenic activity of anaerobic digester sludge
No full textOf four chlorinated guaiacols, tetrachloroguaiacol at 62 muM inhibited acetate methanogenesis, the strongest decreasing activity by 50%. 4,5,6-Trichloroguaiacol, 4,5-dichloroguaiacol, and 4-chloroguaiacol showed 50% inhibition at 0.13, 0.32, and 1.50 mM, respectively. Degradation test results of volatile fatty acids (acetic, propionic, and butyric acid) by anaerobic digester sludge (stored 5 weeks) indicated that syntrophic butyrate degraders of this sludge were more sensitive to tetrachloroguaiacol than acetoclastic methanogens and syntrophic propionate degraders
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