13,210 research outputs found

    An Intelligent Advisor for City Traffic Policies

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    Nowadays, city streets are populated not only by private vehicles but also by public transport, fleets of workers, and deliveries. Since each vehicle class has a maximum cargo capacity, we study in this article how authorities could improve the road traffic by endorsing long term policies to change the different vehicle proportions: sedans, minivans, full size vans, trucks, and motorbikes, without losing the ability of moving cargo throughout the city. We have performed our study in a realistic scenario (map, road traffic characteristics, and number of vehicles) of the city of Malaga and captured the many details into the SUMO microsimulator. After analyzing the relationship between travel times, emissions, and fuel consumption, we have defined a multiobjective optimization problem to be solved, so as to minimize these city metrics. Our results provide a scientific evidence that we can improve the delivery of goods in the city by reducing the number of heavy duty vehicles and fostering the use of vans instead.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. This research has been partially funded by the Spanish MINECO and FEDER projects TIN2014-57341-R, TIN2016-81766-REDT, and TIN2017-88213-R. University of Malaga, Andalucia TECH. Daniel H. Stolfi is supported by a FPU grant (FPU13/00954) from the Spanish MECD. Christian Cintrano is supported by a FPI grant (BES-2015-074805) from Spanish MINECO

    Integrasi Perencanaan Produksi Aggregat Dan Perencanaan Kebutuhan Mesin Pada Proses Produksi Ubin Keramik

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    Usually aggregate production planning and machine requirement planning are conducted separately although there is a close relationship between the two in most production environment. Integration model includes both production and workforce planning decision along with production equipment procurement towards production cost. Research by Behnezhad and Khoshnevis8.2) has shown that mathematical programming model based on this integration could result in cost saving when compared to the use of aggregate production planning and machine requirement planning separately. The advantage of using integration model in tiles production is going to be analyzed in this paper. The integration model is built based on data that is obtained from a tile company and the solution of the model is obtained by using the Quant-system software. The result showed that integration model yield cost saving of Rp.179.453.030,- towards the aggregate production planning and Rp.470.062.980,- towards the machine requirement planning

    Fermi liquid identities for the Infinite U Anderson Model

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    We show how the electron gas methods of Luttinger, Ward and Nozi\`eres can be applied to the infinite U Anderson impurity model within a Schwinger boson treatment. Working to all orders in a 1/N expansion, we show how the Friedel Langreth relationship, the Yamada-Yosida-Yoshimori and the Shiba-Korringa relations can be derived, under the assumption that the spinon and holon fields are gapped. One of the remarkable features of this treatment, is that the Landau amplitudes depend on the exchange of low energy virtual spinons and holons. We end the paper with a discussion on the extension of our approach to the lattice, where the spinon-holon is expected to close at a quantum critical point.Comment: 18 pages. Version 2 revised after referees comment

    Top quark pair production via polarized and unpolarized photons in Supersymmetric QCD

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    QCD corrections to top quark pair production via fusion of both polarized and unpolarized photons are calculated in Supersymmetric Model. The corrections are found to be sizable. The dependence of the corrections on the masses of the supersymmetric particles is also investigated. Furthermore, we studied CP asymmetry effects arising from the complex couplings in the MSSM. The CP violating parameter can reach 10210^{-2} for favorable parameter values.Comment: 26 pages, LaTex, including 12 figures in 12 eps files. submitted to Phys. Rev.

    Desain Eksperimen Untuk Mengoptimalkan Proses Pengecoran Saluran Keluar Teko

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    The most frequently found defect in the casting process of making teapots out flue is that the outlet is too narrow or even blocked at the end of the casting process. There are many factors influence that defect. This defect condition can be represented as the thickness of the casting product. In this paper, the significant factors that influence the thickness of the out flue resulted from the casting process will be analyzed and further got their optimum conditions. Design experiments methods will be implemented here, especially the factorial design method to determine the significant factors along with their optimum conditions. Also, the response surface method will be applied to obtain the approximation model for the thickness of the out flue as a function of the factors found earlier so that the most optimal result can be obtained under a design optimization method. It is concluded from the experiments results and analysis that the significant factors for the thickness of out flue are pouring temperature, sprue radius and holding time. The optimum conditions of those factors are 475°C, 29.6 mm and 8 seconds respectively with 2.54 mm thickness

    Biodegradation of Synthetic Biphasic Calcium Phosphate and Biological Calcified Substratum by Cells of Hemopoietic Origin

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    Different types of osteoclastic cells (authentic osteoclasit from human giant cell tumor and bone marrow of newborn rats; newly-formed osteoclasts from adult rat bone marrow), giant multinucleated cells and macrophages were studied for their effect on synthetic and natural mineralized substrata. Biphasic calcium phosphate ceramic consisted of hydroxyapatite and beta tricalcium phosphate was chosen for in vitro experiments, and dentine served as a positive control for cell resorbing activity . Our results show the limited capacity of authentic and newly-formed osteoclasts to resorb synthetic ceramic as compared to that of natural substrata. In vitro cell-mediated biodegradation included also modifications of the synthetic substratum surface caused presumably by phagocytosis of the material

    Single chargino production via gluon-gluon fusion in a supersymmetric theory with an explicit R-parity violation

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    We studied the production of single charginoχ~1±\tilde{\chi}_1^{\pm} accompanied by μ\mu^{\mp} lepton via gluon-gluon fusion at the LHC. The numerical analysis of their production rates is carried out in the mSUGRA scenario with some typical parameter sets. The results show that the cross sections of the χ~1±μ\tilde{\chi}_1^{\pm}\mu^{\mp} productions via gluon-gluon collision are in the order of 11021 \sim 10^{2} femto barn quantitatively at the CERN LHC, and can be competitive with production mechanism via quark-antiquark annihilation process.Comment: LaTex file, 18 pages, 4 EPS file

    Lattice Boltzmann study on Kelvin-Helmholtz instability: the roles of velocity and density gradients

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    A two-dimensional lattice Boltzmann model with 19 discrete velocities for compressible Euler equations is proposed (D2V19-LBM). The fifth-order Weighted Essentially Non-Oscillatory (5th-WENO) finite difference scheme is employed to calculate the convection term of the lattice Boltzmann equation. The validity of the model is verified by comparing simulation results of the Sod shock tube with its corresponding analytical solutions. The velocity and density gradient effects on the Kelvin-Helmholtz instability (KHI) are investigated using the proposed model. Sharp density contours are obtained in our simulations. It is found that, the linear growth rate γ\gamma for the KHI decreases with increasing the width of velocity transition layer Dv{D_{v}} but increases with increasing the width of density transition layer Dρ{D_{\rho}}. After the initial transient period and before the vortex has been well formed, the linear growth rates, γv\gamma_v and γρ\gamma_{\rho}, vary with Dv{D_{v}} and Dρ{D_{\rho}} approximately in the following way, lnγv=abDv\ln\gamma_{v}=a-bD_{v} and γρ=c+elnDρ(Dρ<DρE)\gamma_{\rho}=c+e\ln D_{\rho} ({D_{\rho}}<{D_{\rho}^{E}}), where aa, bb, cc and ee are fitting parameters and DρE{D_{\rho}^{E}} is the effective interaction width of density transition layer. When Dρ>DρE{D_{\rho}}>{D_{\rho}^{E}} the linear growth rate γρ\gamma_{\rho} does not vary significantly any more. One can use the hybrid effects of velocity and density transition layers to stabilize the KHI. Our numerical simulation results are in general agreement with the analytical results [L. F. Wang, \emph{et al.}, Phys. Plasma \textbf{17}, 042103 (2010)].Comment: Accepted for publication in PR
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