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Specific System (specific + system)
Selected AbstractsCoating and near-surface modification design strategies for protective and functional surfacesMATERIALS AND CORROSION/WERKSTOFFE UND KORROSION, Issue 11 2005M.P. Brady Abstract This paper discusses strategies for controlling the surface chemistry and microstructure of materials to form protective and functional surfaces through controlled gas-metal reactions. Potential applications range from oxidation, corrosion, and wear resistance to electrochemical devices such as fuel cells to catalysts. Phenomenological examples are presented for coatings designed to self-grade under oxidizing conditions, and for the growth of simple and complex (binary and ternary) nitride and carbide phase surface layers by nitridation and carburization reactions. Specific systems discussed include environmental barrier coatings (EBCs) for Si-based ceramics such as Si3N4 and SiC, the growth of continuous, protective CrN/Cr2N, TiN, VN, NiNbVN, and related simple nitride layers on Fe- and Ni-base alloys, the possible formation of ternary nitride and carbide surface phases (e.g. Ti3AlC2 and related MAX-phases) on intermetallic surfaces to improve oxidation resistance, and the formation of composite near-surface structures in Ag-SiO2 and Co(Mo)-Co6Mo6C2 systems. [source] Experimental analysis of a mass storage systemCONCURRENCY AND COMPUTATION: PRACTICE & EXPERIENCE, Issue 15 2006Shahid Bokhari Abstract Mass storage systems (MSSs) play a key role in data-intensive parallel computing. Most contemporary MSSs are implemented as redundant arrays of independent/inexpensive disks (RAID) in which commodity disks are tied together with proprietary controller hardware. The performance of such systems can be difficult to predict because most internal details of the controller behavior are not public. We present a systematic method for empirically evaluating MSS performance by obtaining measurements on a series of RAID configurations of increasing size and complexity. We apply this methodology to a large MSS at Ohio Supercomputer Center that has 16 input/output processors, each connected to four 8 + 1 RAID5 units and provides 128 TB of storage (of which 116.8 TB are usable when formatted). Our methodology permits storage-system designers to evaluate empirically the performance of their systems with considerable confidence. Although we have carried out our experiments in the context of a specific system, our methodology is applicable to all large MSSs. The measurements obtained using our methods permit application programmers to be aware of the limits to the performance of their codes. Copyright © 2006 John Wiley & Sons, Ltd. [source] Analysis of the effects of Nyquist pulse-shaping on the performance of OFDM systems with carrier frequency offsetEUROPEAN TRANSACTIONS ON TELECOMMUNICATIONS, Issue 1 2009Peng Tan An exact method for calculating the bit error rate (BER) of an uncoded orthogonal frequency-division multiplexing (OFDM) system with transmitter Nyquist pulse-shaping over AWGN channels in the presence of frequency offset is derived. This method represents a unified way to calculate the BER of this system with different one- and two-dimensional subcarrier modulation formats. The precise BER expressions are obtained using a characteristic function method. The effects of several widely referenced Nyquist pulse-shapings, including the Franks pulse, the raised-cosine pulse, the ,better than' raised-cosine (BTRC) pulse, the second-order continuous window (SOCW), the double-jump pulse and the polynomial pulse on intercarrier interference (ICI) reduction and BER improvement of the system with carrier frequency offset are examined in the AWGN channel. The dependence of the BER on the roll-off factor of the pulse employed for a specific system in the presence of frequency offset is investigated. Analysis and numerical results show that the Franks pulse exhibits the best performance among the Nyquist pulses considered in most cases. Copyright © 2008 John Wiley & Sons, Ltd. [source] Aligned, Ultralong Single-Walled Carbon Nanotubes: From Synthesis, Sorting, to Electronic DevicesADVANCED MATERIALS, Issue 21 2010Zhongfan Liu Abstract Aligned, ultralong single-walled carbon nanotubes (SWNTs) represent attractive building blocks for nanoelectronics. The structural uniformity along their tube axis and well-ordered two-dimensional architectures on wafer surfaces may provide a straightforward platform for fabricating high-performance SWNT-based integrated circuits. On the way towards future nanoelectronic devices, many challenges for such a specific system also exist. This Review summarizes the recent advances in the synthesis, identification and sorting, transfer printing and manipulation, device fabrication and integration of aligned, ultralong SWNTs in detail together with discussion on their major challenges and opportunities for their practical application. [source] Bayesian estimation of traffic lane stateINTERNATIONAL JOURNAL OF ADAPTIVE CONTROL AND SIGNAL PROCESSING, Issue 1 2003Ivan Nagy Abstract Modelling of large transportation systems requires a reliable description of its elements that can be easily adapted to the specific situation. This paper offers mixture model as a flexible candidate for modelling of such element. The mixture model describes particular and possibly very different states of a specific system by its individual components. A hierarchical model built on such elements can describe complexes of big city communications as well as railway or highway networks. Bayesian paradigm is adopted for estimation of parameters and the actual component label of the mixture model as it serves well for the subsequent decision making. As a straightforward application of Bayesian method to mixture models leads to infeasible computations, an approximation is applied. For normal stochastic variations, the resulting estimation algorithm reduces to a simple recursive weighted least squares. The elementary modelling is demonstrated on a model of traffic flow state in a single point of a roadway. The examples for simulated as well as real data show excellent properties of the suggested model. They represent much wider set of extensive tests made. Copyright © 2003 John Wiley & Sons, Ltd. [source] Isolation and characterization of a transposon mutant of Pseudomonas aeruginosa affecting uptake of dibenzothiophene in n -tetradecaneLETTERS IN APPLIED MICROBIOLOGY, Issue 2 2003K. Noda Abstract Aims: Isolation and characterization of a transposon mutant of Pseudomonas aeruginosa affecting the uptake of dibenzothiophene (DBT) in n -tetradecane (n -TD). Methods and Results: The dsz desulphurization gene cluster from Rhodococcus erythropolis KA2-5-1 was transferred to the chromosome of P. aeruginosa NCIMB9571 using a transposon vector. A recombinant (named PARM1) was obtained which was able to desulphurize DBT in water, but not in n -TD. Conclusions: PARM1 is a mutant deficient in a DBT transport system operational in n -TD. This transport system is independent of rhamnolipids and of the n -alkane transport system. Significance and Impact of the Study:Pseudomonas aeruginosa NCIMB9571 seems to have a specific system of transporting hydrophobic compounds such as DBT in oil. [source] Addressing the Systems-based Practice Core Competency: A Simulation-based CurriculumACADEMIC EMERGENCY MEDICINE, Issue 12 2005Ernest E. Wang MD Systems-based practice is one of the six core competencies implemented by the Accreditation Council for Graduate Medical Education to direct residency educational outcome assessment and accreditation. Emergency medicine,specific systems-based practice criteria have been described to define the expected knowledge and skill sets pertinent to emergency medicine practitioners. High-fidelity patient simulation is increasingly used in graduate medical education to augment case-based learning. The authors describe a simulation-based curriculum to address the emergency medicine,specific systems-based practice core competency. [source] Multiple ligand simultaneous docking: Orchestrated dancing of ligands in binding sites of proteinJOURNAL OF COMPUTATIONAL CHEMISTRY, Issue 10 2010Huameng Li Abstract Present docking methodologies simulate only one single ligand at a time during docking process. In reality, the molecular recognition process always involves multiple molecular species. Typical protein,ligand interactions are, for example, substrate and cofactor in catalytic cycle; metal ion coordination together with ligand(s); and ligand binding with water molecules. To simulate the real molecular binding processes, we propose a novel multiple ligand simultaneous docking (MLSD) strategy, which can deal with all the above processes, vastly improving docking sampling and binding free energy scoring. The work also compares two search strategies: Lamarckian genetic algorithm and particle swarm optimization, which have respective advantages depending on the specific systems. The methodology proves robust through systematic testing against several diverse model systems: E. coli purine nucleoside phosphorylase (PNP) complex with two substrates, SHP2NSH2 complex with two peptides and Bcl-xL complex with ABT-737 fragments. In all cases, the final correct docking poses and relative binding free energies were obtained. In PNP case, the simulations also capture the binding intermediates and reveal the binding dynamics during the recognition processes, which are consistent with the proposed enzymatic mechanism. In the other two cases, conventional single-ligand docking fails due to energetic and dynamic coupling among ligands, whereas MLSD results in the correct binding modes. These three cases also represent potential applications in the areas of exploring enzymatic mechanism, interpreting noisy X-ray crystallographic maps, and aiding fragment-based drug design, respectively. © 2010 Wiley Periodicals, Inc. J Comput Chem, 2010 [source] Fluorenyl based syndiotactic specific metallocene catalysts structural features, origin of syndiospecificityMACROMOLECULAR SYMPOSIA, Issue 1 2004Abbas Razavi Abstract The stereochemistry of propylene insertion/propagation reactions with a variety of Cs symmetric fluorenyl- containing single site catalysts is discussed. Our recent results indicate that independent of the chemical composition of the ancillary ligand fragments, or nature of the transition metal, active sites with local Cs symmetry and enantiotopic coordination positions behave syndioselectively in the general context of chain migratory insertion mechanism. Perfect bilateral symmetry neither exists nor is required in these processes. In this context the mechanism of syndiospecific polymerization is revisited by taking into account the structural characteristics and catalytic behavior of the original metallocene based (,5 -C5H4 -CMe2 -,5 -C13H8) MCl2/ MAO; M = Zr (1), Hf (2) catalyst systems and new syndiotactic specific systems including (,5 -C5H4 -CPh2-,5-3,6-di-tBut-C13H6)ZrCl2 (3), ,1,,5 -(,Me2Si)(3,6-di-tBut-Flu)(t-ButN)MCl2/ MAO; M =Ti (4), Zr (5) and ,1,,5 -(,Me2Si)(2,7-di-tBut-Flu)(t-ButN)MCl2/ MAO; M = Ti (6), Zr (7). [source] | |||||||||||||