2,485 research outputs found

    Analysis on the hull girder ultimate strength of a bulk carrier using simplified method based on an incremental-iterative approach

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    The hull girder ultimate strength of a typical bulk carrier is analyzed using a simplified method based on an incremental-iterative approach. First, vertical bending moment is examined by seven different methods. The moment versus curvature curves and the values of the ultimate longitudinal moments at collapse states are determined for both hogging and sagging cases. Second, the ultimate strength under coupled vertical and horizontal bending moment is accounted. An interaction curve is obtained, which corresponds to the results of series of calculation for the ship hull subject to bending conditions with different angles of curvature. It is found that the interaction curve is asymmetrical because the hull cross section is not symmetrical with respect to the horizontal axis and the structural response of the elements under compression is different from that under tension due to nonlinearity caused by buckling. The angles of the resultant bending moment vector and that of the curvature vector are different in investigated cases. The interaction design equations proposed by other researches are also addressed to discuss the results presented by this study

    T1T_1- and T2T_2-spin relaxation time limitations of phosphorous donor electrons near crystalline silicon to silicon dioxide interface defects

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    A study of donor electron spins and spin--dependent electronic transitions involving phosphorous (31^{31}P) atoms in proximity of the (111) oriented crystalline silicon (c-Si) to silicon dioxide (SiO2_{2}) interface is presented for [31^{31}P] = 1015^{15} cm3\mathrm{cm}^{-3} and [31^{31}P] = 1016^{16} cm3\mathrm{cm}^{-3} at about liquid 4^4He temperatures (T=5T = 5 K15\mathrm{K} - 15 K\mathrm{K}). Using pulsed electrically detected magnetic resonance (pEDMR), spin--dependent transitions between the \Phos donor state and two distinguishable interface states are observed, namely (i) \Pb centers which can be identified by their characteristic anisotropy and (ii) a more isotropic center which is attributed to E^\prime defects of the \sio bulk close to the interface. Correlation measurements of the dynamics of spin--dependent recombination confirm that previously proposed transitions between \Phos and the interface defects take place. The influence of these electronic near--interface transitions on the \Phos donor spin coherence time T2T_2 as well as the donor spin--lattice relaxation time T1T_1 is then investigated by comparison of spin Hahn--echo decay measurements obtained from conventional bulk sensitive pulsed electron paramagnetic resonance and surface sensitive pEDMR, as well as surface sensitive electrically detected inversion recovery experiments. The measurements reveal that both T2T_2 and T1T_1 of \Phos donor electrons spins in proximity of energetically lower interface states at T13T\leq 13 K are reduced by several orders of magnitude

    Poor survival outcomes in HER2 positive breast cancer patients with low grade, node negative tumours

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    We present a retrospective analysis on a cohort of low-grade, node-negative patients showing that human epidermal growth factor receptor 2 (HER2) status significantly affects the survival in this otherwise very good prognostic group. Our results provide support for the use of adjuvant trastuzumab in patients who are typically classified as having very good prognosis, not routinely offered standard chemotherapy, and who as such do not fit current UK prescribing guidelines for trastuzumab

    Three-Dimensional Simulation of Turbulent Hot-Jet Ignition for Air-CH4-H2 Deflagration in a Confined Volume

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    This work describes essential aspects of the ignition and deflagration process initiated by the injection of a hot transient gas jet into a narrowly confined volume containing air-CH4-H2 mixture. Driven by the pressure difference between a prechamber and a long narrow constant-volume-combustion (CVC) chamber, the developing jet or puff involves complex processes of turbulent jet penetration and evolution of multi-scale vortices in the shear layer, jet tip, and adjacent confined spaces. The CVC chamber contains stoichiometric mixtures of air with gaseous fuel initially at atmospheric conditions. Fuel reactivity is varied using two different CH4/H2 blends. Jet momentum is varied using different pre-chamber pressures at jet initiation. The jet initiation and the subsequent ignition events generate pressure waves that interact with the mixing region and the propagating flame, depositing baroclinic vorticity. Transient three-dimensional flow simulations with detailed chemical kinetics are used to model CVC mixture ignition. Pre-ignition gas properties are then examined to develop and verify criteria to predict ignition delay time using lower-cost non-reacting flow simulations for this particular case of study

    Photon Shot Noise Dephasing in the Strong-Dispersive Limit of Circuit QED

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    We study the photon shot noise dephasing of a superconducting transmon qubit in the strong-dispersive limit, due to the coupling of the qubit to its readout cavity. As each random arrival or departure of a photon is expected to completely dephase the qubit, we can control the rate at which the qubit experiences dephasing events by varying \textit{in situ} the cavity mode population and decay rate. This allows us to verify a pure dephasing mechanism that matches theoretical predictions, and in fact explains the increased dephasing seen in recent transmon experiments as a function of cryostat temperature. We investigate photon dynamics in this limit and observe large increases in coherence times as the cavity is decoupled from the environment. Our experiments suggest that the intrinsic coherence of small Josephson junctions, when corrected with a single Hahn echo, is greater than several hundred microseconds.Comment: 5 pages, 4 figures; includes Supporting Online Material of 6 pages with 5 figure

    Anatomical structures and fiber morphology of new kenaf varieties

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    Kenaf plant is claimed as one of the fast-growing herbaceous plants with the high potential as a fiber material or lignocellulosic material. Nine kenaf varieties i.e., Q-Ping, KK60, V12, V19, V36, V132 and NS V133 and TK were introduced recently by Taman Pertanian Universiti, Universiti Putra Malaysia as one of the potential plant to replace tobacco plantation. Since, these nine kenaf varieties are new to Malaysia, therefore, there is a need to study their anatomical structures and fiber morphology as well as microscopic appearances to understand their different and similarity. Cell morphology and anatomical appearances were observed and evaluated under the image analysis system (Leitz DMRB). From the results, V19 and V12 had the wider ray among the nine varieties, whereas other varieties in their microscopic appearance were almost similar to those observed in many diffuse-porous hardwoods. The longest fiber length was observed in variety TK (2.96 mm) followed by V36. Q-ping showed the widest fiber diameter and lumen diameter amongst the nine varieties, with value of 28.64 μm in bast fiber and 28.06 μm in core diameter. However, Q-ping had the thinnest core cell wall with the thickness of 3.34 μm. In term of fiber length, all the kenaf varieties bast fiber has longer fiber than core fiber. The kenaf core of nine varieties has wider fiber diameter and fiber lumen diameter than the bast fiber. Conclusively, although kenaf exhibit similarity in some fiber morphology and anatomical structures, however, there still some distinction that can be used to differentiate these kenaf variety
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