257 research outputs found

    A HYBRID SELF-ORGANIZING SCHEDULING METHOD FOR SHIPS IN RESTRICTED TWO-WAY WATERWAYS

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    Traffic conflicts between ships are one of the most important reasons causing delays in restricted waterways. Aiming to improve the traffic efficiency, a hybrid self-organizing scheduling (HSOS) method for restricted two-way waterways is proposed. Ship transportation system is treated as a distributive and self-organized system under uncertainties. Each ship makes the decision on when to enter the waterway and how to keep the safe distance between them, while the VTS center could manage the direction of traffic flow according to the navigation situations. In order to reduce the traffic conflict between the opposite directions, small ships are given higher priority than the large ships in the same direction. When the large ships are accumulating, they are given higher priority than small ships in the same direction. The large ships are delayed while small ships decrease the waiting time. The trade-off between small and large ships can enhance efficiency by accumulating the large ships. Comparing the results from HSOS with First Come First Served (FCFS), it can effectively reduce the average delays brought by large ships, especially at high arrival rates

    Two weight inequality for Hankel form on weighted Bergman spaces induced by doubling weights

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    The boundedness of the small Hankel operator hfν(g)=Pν(fgˉ)h_f^\nu(g)=P_\nu(f\bar{g}), induced by an analytic symbol ff and the Bergman projection PνP_\nu associated to ν\nu, acting from the weighted Bergman space A^p_\om to AνqA^q_\nu is characterized on the full range 0<p,q<0<p,q<\infty when ω,ν\omega,\nu belong to the class D\mathcal{D} of radial weights admitting certain two-sided doubling conditions. Certain results obtained are equivalent to the boundedness of bilinear Hankel forms, which are in turn used to establish the weak factorization Aηq=Aωp1Aνp2A_{\eta}^{q}=A_{\omega}^{p_{1}}\odot A_{\nu}^{p_{2}}, where 1<q,p1,p2<1<q,p_{1},p_{2}<\infty such that q1=p11+p21q^{-1}=p_{1}^{-1}+p_{2}^{-1} and η~1qω~1p1ν~1p2\widetilde{\eta}^{\frac{1}{q}}\asymp\widetilde{\omega}^{\frac{1}{p_{1}}}\widetilde{\nu}^{\frac{1}{p_{2}}}. Here τ~(r)=r1τ(t)dt/(1t)\widetilde{\tau}(r)=\int_r^1\tau(t)\,dt/(1-t) for all 0r<10\le r<1

    4-(3-Nitro­phen­yl)-3-(phenyl­sulfon­yl)but-3-en-2-one

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    The C=C double bond in the title mol­ecule, C16H13NO5S, has an E configuration. The crystal structure is stabilized by C—H⋯O hydrogen bonds. There is also a weak C—H⋯π-ring inter­action in the structure

    The effect of cooling rate on the wear performance of a ZrCuAlAg bulk metallic glass

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    In the present work, the local atomic ordering and the wear performance of ZrCuAlAg bulk metallic glass (BMG) samples with different diameters have been studied using transmission electron microscopy (TEM) plus autocorrelation function analysis, and pin-on-disc dry sliding wear experiments. Differential scanning calorimetry and TEM studies show that smaller diameter BMG sample has higher free volume and less local atomic ordering. The wear experiments demonstrate that with the same chemical composition, the smaller BMG sample exhibits higher coefficient of friction, higher wear rate, and rougher worn surface than those of the larger ones. Compared with larger BMG sample, the faster cooling rate of the smaller sample results in looser atomic configuration with more free volume, which facilitates the formation of the shear bands, and thus leads to larger plasticity and lower wear resistance. The results provide more quantitative understanding on the relationship among the cooling rate, the local atomic ordering, and the wear performance of BMGs

    Research on Water Absorption and Frost Resistance of Concrete Coated with Different Impregnating Agents for Ballastless Track Structure

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    In consideration of performance requirement of ballastless track concrete in cold regions of China, 3 types of commercially available impregnating agents were employed to research their effect on water absorption and frozen resistance of concrete, containing silanes, potassium silicate and osmotic curing agent. The results presented that coating silanes was the most effective on the reduction of water absorption among all employed impregnating agents, because of the most significant character change of concrete surface from hydrophilicity to hydrophobicity which could be proved by the contact angle test of concrete. The promotion on frozen resistance of concrete was not as significant as that for water absorption by coating 3 commercially available types of impregnant agents, because of the spalling damage on concrete surface during the freezing-thawing cycles
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