354 research outputs found

    Elasticity solutions for a transversely isotropic functionally graded circular plate subject to an axisymmetric transverse load qrk

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    AbstractThis paper considers the bending of transversely isotropic circular plates with elastic compliance coefficients being arbitrary functions of the thickness coordinate, subject to a transverse load in the form of qrk (k is zero or a finite even number). The differential equations satisfied by stress functions for the particular problem are derived. An elaborate analysis procedure is then presented to derive these stress functions, from which the analytical expressions for the axial force, bending moment and displacements are obtained through integration. The method is then applied to the problem of transversely isotropic functionally graded circular plate subject to a uniform load, illustrating the procedure to determine the integral constants from the boundary conditions. Analytical elasticity solutions are presented for simply-supported and clamped plates, and, when degenerated, they coincide with the available solutions for an isotropic homogenous plate. Two numerical examples are finally presented to show the effect of material inhomogeneity on the elastic field in FGM plates

    Using system simulation to search for the optimal multi-ordering policy for perishable goods

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    [EN] This paper explores the possibility that perishable goods can be ordered several times in a single period after considering the cost of Marginal contribution, Marginal loss, Shortage, and Purchasing under stochastic demand. In order to determine the optimal ordering quantity to improve the traditional newsvendor and maximize the total expected profits, and then sensitivity analysis is taken to realize the influence of the parameters on total expected profits and decision variables respectively. In addition, this paper designed a multi-order computerized system with Monte Carlo method to solve the optimal solution under stochastic demand. Based on numerical examples, this paper verified the feasibility and efficiency of the proposed model. Finally, several specific conclusions are drawn for practical applications and future studies.Huang, Y.; Chang, X.; Ding, Y. (2019). Using system simulation to search for the optimal multi-ordering policy for perishable goods. International Journal of Production Management and Engineering. 7(1):49-62. https://doi.org/10.4995/ijpme.2019.10745SWORD496271Azoury, K.S., Miller, B.L. (1984). A comparison of the optimal ordering levels of bayesian and non-bayesian inventory models, Management Science, 30(8), 993-1003. https://doi.org/10.1287/mnsc.30.8.993Alfares, H.K., Elmorra, H.H. (2005). The distribution-free newsboy problem: extensions to the shortage penalty case, International Journal of Production Economics, 93-94(8), 465-477. https://doi.org/10.1016/j.ijpe.2004.06.043Chung, C.S., Flynn, J. (2001). A newsboy problem with reactive production, Computers & Operations Research, 28(8), 751-765. https://doi.org/10.1016/S0305-0548(00)00006-XChun, Y.H. (2003). Optimal pricing and ordering policies for perishable commodities, European Journal of Operational Research, 144(1), 68-82. https://doi.org/10.1016/S0377-2217(01)00351-4Chen, L.H., Chen, Y.C. (2009). A newsboy problem with a simple reservation arrangement. Computers & Industrial Engineering, 56(1), 157-160. https://doi.org/10.1016/j.cie.2008.04.010Dian, J.R. (1990). A high-low search algorithm for a newsboy problem with delayed information feedback. Operations Research, 38(5), 838-846. https://doi.org/10.1287/opre.38.5.838Dye, C.Y., Ouyang, L.Y. (2005). An EOQ model for perishable items under stock-dependent selling rate and time-dependent partial backlogging. European Journal of Operational Research, 163(3), 776-783. https://doi.org/10.1016/j.ejor.2003.09.027Fujiwara, O., Soewandi, H., Sedarage, D. (1997). An optimal ordering and issuing policy for a two-stage inventory system for perishable products. European Journal of Operational Research, 99(2), 412-424. https://doi.org/10.1016/S0377-2217(95)00365-7Gallego, G., Moon, I. (1993). The distribution free newsboy problem: review and extensions. Journal of the Operational Research Society, 44(8), 825-834. https://doi.org/10.1057/jors.1993.141Khouja, M. (1999). The single-period (news-vendor) problem: literature review and suggestions for future research. Omega, 27(5), 537-553. https://doi.org/10.1016/S0305-0483(99)00017-1Khouja, M.J. (2000). Optimal ordering, discounting, and pricing in the single-period problem. International Journal of Production Economics, 65(2), 201-216. https://doi.org/10.1016/S0925-5273(99)00027-4Lau, H., Lau, H. (1998). Decision models for single-period products with two ordering opportunities. International Journal of Production Economics, 55(1), 57-70. https://doi.org/10.1016/S0925-5273(98)00040-1Padmanabhan, G., Vrat, P. (1995). EOQ models for perishable items under stock dependent selling rate. European Journal of Operational Research, 86(2), 281-292. https://doi.org/10.1016/0377-2217(94)00103-JPando, V., Luis, A.S.J., Juan, G.L., Sicilia, J. (2013). A newsboy problem with an emergency order under a general backorder rate function. Omega, 41(6), 1020-1028. https://doi.org/10.1016/j.omega.2013.01.003Zheng, M., Wu, K., Shu, Y. (2016). Newsvendor problems with demand forecast updating and supply constraints. Computers & Operations Research, 67, 193-206. https://doi.org/10.1016/j.cor.2015.10.00

    Anthropogenic point-source and non-point-source nitrogen inputs into Huai River basin and their impacts on riverine ammonia–nitrogen flux

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    This study provides a new approach to estimate both anthropogenic non-point-source and point-source nitrogen (N) inputs to the landscape, and determines their impacts on riverine ammonia-nitrogen (AN) flux, providing a foundation for further exploration of anthropogenic effects on N pollution. Our study site is Huai River basin of China, a water–shed with one of the highest levels of N input in the world. Multi-year average (2003-2010) inputs of N to the watershed are 27 200 ± 1100 kg N km-2 yr-1. Non-point sources comprised about 98 % of total N input, and only 2 % of inputs are directly added to the aquatic ecosystem as point sources. Fertilizer application was the largest non-point source of new N to the Huai River basin (69 % of net anthropogenic N inputs), followed by atmospheric deposition (20 %), N fixation in croplands (7 %), and N content of imported food and feed (2 %). High N inputs showed impacts on riverine AN flux: fertilizer application, point-source N input, and atmospheric N deposition were proved as more direct sources to riverine AN flux. Modes of N delivery and losses associated with biological denitrification in rivers, water consumption, interception by dams may influence the extent of export of riverine AN flux from N sources. Our findings highlight the importance of anthropogenic N inputs from both point sources and non-point sources in heavily polluted watersheds, and provide some implications for AN prediction and management.This study was financially supported by the Key Research Program of the Chinese Academy of Sciences (no. KZZD-EW-10-02-3), the 13th Five-Year Plan of Chinese Academy of Sciences (no. YSW2013B02) and State Key Laboratory of Urban and Regional Ecology scientific project (no. SKLURE2013-1-05). The authors wish to express their gratitude to the China Scholarship Council (201408110138) for funding the visiting venture that generated this paper, and to Huai River Basin Water Resources Protection Bureau and Hydrologic Information Center of Huai River Commission for providing water quality and hydrological data

    Superconductivity and Stoichiometry in the BSCCO-family Materials

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    We report on magnetization, c-axis and ab-plane resistivity, critical current, electronic band structure and superconducting gap properties. Bulk measurements and photoemission data were taken on similar samples.Comment: 4 pages, latex, to be published in Journal of Superconductivity. two figures available from Jian Ma at [email protected]

    The energy spectrum of all-particle cosmic rays around the knee region observed with the Tibet-III air-shower array

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    We have already reported the first result on the all-particle spectrum around the knee region based on data from 2000 November to 2001 October observed by the Tibet-III air-shower array. In this paper, we present an updated result using data set collected in the period from 2000 November through 2004 October in a wide range over 3 decades between 101410^{14} eV and 101710^{17} eV, in which the position of the knee is clearly seen at around 4 PeV. The spectral index is -2.68 ±\pm 0.02(stat.) below 1PeV, while it is -3.12 ±\pm 0.01(stat.) above 4 PeV in the case of QGSJET+HD model, and various systematic errors are under study now.Comment: 12 pages, 7 figures, accepted by Advances in space researc

    Moon Shadow by Cosmic Rays under the Influence of Geomagnetic Field and Search for Antiprotons at Multi-TeV Energies

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    We have observed the shadowing of galactic cosmic ray flux in the direction of the moon, the so-called moon shadow, using the Tibet-III air shower array operating at Yangbajing (4300 m a.s.l.) in Tibet since 1999. Almost all cosmic rays are positively charged; for that reason, they are bent by the geomagnetic field, thereby shifting the moon shadow westward. The cosmic rays will also produce an additional shadow in the eastward direction of the moon if cosmic rays contain negatively charged particles, such as antiprotons, with some fraction. We selected 1.5 x10^{10} air shower events with energy beyond about 3 TeV from the dataset observed by the Tibet-III air shower array and detected the moon shadow at 40σ\sim 40 \sigma level. The center of the moon was detected in the direction away from the apparent center of the moon by 0.23^\circ to the west. Based on these data and a full Monte Carlo simulation, we searched for the existence of the shadow produced by antiprotons at the multi-TeV energy region. No evidence of the existence of antiprotons was found in this energy region. We obtained the 90% confidence level upper limit of the flux ratio of antiprotons to protons as 7% at multi-TeV energies.Comment: 13pages,4figures; Accepted for publication in Astroparticle Physic

    The ARGO-YBJ Experiment Progresses and Future Extension

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    Gamma ray source detection above 30TeV is an encouraging approach for finding galactic cosmic ray origins. All sky survey for gamma ray sources using wide field of view detector is essential for population accumulation for various types of sources above 100GeV. To target the goals, the ARGO-YBJ experiment has been established. Significant progresses have been made in the experiment. A large air shower detector array in an area of 1km2 is proposed to boost the sensitivity. Hybrid detection with multi-techniques will allow a good discrimination between different types of primary particles, including photons and protons, thus enable an energy spectrum measurement for individual specie. Fluorescence light detector array will extend the spectrum measurement above 100PeV where the second knee is located. An energy scale determined by balloon experiments at 10TeV will be propagated to ultra high energy cosmic ray experiments

    In vivo and in vitro proinflammatory effects of particulate air pollution (PM10).

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    Epidemiologic studies have reported associations between fine particulate air pollution, especially particles less than 10 mm in diameter (PM10), and the development of exacerbations of asthma and chronic obstructive pulmonary disease. However, the mechanism is unknown. We tested our hypothesis that PM10 induces oxidant stress, causing inflammation and injury to airway epithelium. We assessed the effects of intratracheal instillation of PM10 in rat lungs. The influx of inflammatory cells was measured in bronchoalveolar lavage (BAL). Airspace epithelial permeability was assessed as total protein in bronchoalveolar lavage fluid (BALF) in vivo. The oxidant properties of PM10 were determined by their ability to cause changes in reduced glutathione (GSH) and oxidized glutathione (GSSG). We also compared the effects of PM10 with those of fine (CB) and ultrafine (ufCB) carbon black particles. Six hours after intratracheal instillation of PM10, we noted an influx of neutrophils (up to 15% of total BAL cells) in the alveolar space, increased epithelial permeability, an increase in total protein in BALF from 0.39 +/- 0.01 to 0.62 +/- 0.01 mg/ml (mean +/- SEM) and increased lactate dehydrogenase concentrations in BALF. An even greater inflammatory response was observed after intratracheal instillation of ufCB, but not after CB instillation. PM10 had oxidant activity in vivo, as shown by decreased GSH in BALF (from 0.36 +/- 0.05 to 0.25 +/- 0.01 nmol/ml) after instillation. BAL leukocytes from rats treated with PM10 produced greater amounts of nitric oxide, measured as nitrite (control 3.07 +/- 0.33, treated 4.45 +/- 0.23 mM/1 x 10(6) cells) and tumor necrosis factor alpha (control 21.0 +/- 3.1, treated 179.2 +/- 29.4 unit/1 x 10(6) cells) in culture than BAL leukocytes obtained from control animals. These studies provide evidence that PM10 has free radical activity and causes lung inflammation and epithelial injury. These data support our hypothesis concerning the mechanism for the adverse effects of particulate air pollution on patients with airway diseases

    High Altitude test of RPCs for the ARGO-YBJ experiment

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    A 50 m**2 RPC carpet was operated at the YangBaJing Cosmic Ray Laboratory (Tibet) located 4300 m a.s.l. The performance of RPCs in detecting Extensive Air Showers was studied. Efficiency and time resolution measurements at the pressure and temperature conditions typical of high mountain laboratories, are reported.Comment: 16 pages, 10 figures, submitted to Nucl. Instr. Met
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