7,747 research outputs found
Revivification of confinement resonances in the photoionization of @C endohedral atoms far above thresholds
It is discovered theoretically that significant confinement resonances in an
photoionization of a \textit{multielectron} atom encaged in carbon
fullerenes, A@C, may re-appear and be strong at photon energies far
exceeding the ionization threshold, as a general phenomenon. The reasons
for this phenomenon are unraveled. The Ne photoionization of the
endohedral anion Ne@C in the photon energy region of about a
thousand eV above the threshold is chosen as case study.Comment: 3 pages, 1 figure, Revtex
Non-cooperative joint replenishment under asymmetric information
Cataloged from PDF version of article.We consider jointly replenishing n ex-ante identical firms that operate under an EOQ like setting using a
non-cooperative game under asymmetric information. In this game, each firm, upon being privately
informed about its demand rate (or inventory cost rate), submits a private contribution to an intermediary
that specifies how much it is willing to pay for its replenishment per unit of time and the intermediary
determines the maximum feasible frequency for the joint orders that would finance the fixed
replenishment cost. We show that a Bayesian Nash equilibrium exists and characterize the equilibrium
in this game. We also show that the contributions are monotone increasing in each firm’s type. We finally
conduct a numerical study to compare the equilibrium to solutions obtained under independent and
cooperative ordering, and under full information. The results show that while information asymmetry
eliminates free-riding in the contributions game, the resulting aggregate contributions are not as high
as under full information, leading to higher aggregate costs.
2013 Elsevier B.V. All rights reserved
Couple stress effects in a thin film bonded to a half-space
This study investigates the contact mechanics of a thin film laying on an elastic substrate within the context of couple-stress elasticity. It aims to introduce the effects of material internal length scale, which has proven an effective way of modeling structures at micro to nano-scales, allowing to capture their size dependent behavior. Specifically, stress analysis for a thin film bonded to a couple stress elastic half-space is considered under plane strain loading conditions by assuming that both shear stress and couple tractions are exchanged between the thin film and the substrate. The problem is converted to a singular integral equation, which is solved by expanding the shear stress tractions as a Chebyshev series. The results show that the introduction of couple tractions decreases the shear stress tractions and the axial load in the thin film. When the characteristic length is sufficiently small, but still finite, the results for classical elastic behavior are approached
Multi-period supplier selection under price uncertainty
Cataloged from PDF version of article.We consider a problem faced by a procurement manager who needs to purchase a large volume of multiple items over multiple periods from multiple suppliers that provide base prices and discounts. Discounts are contingent on meeting various conditions on total volume or spend, and some are tied to future realizations of random events that can be mutually verified. We formulate a scenario-based multi-stage stochastic optimization model that allows us to consider random events such as a drop in price because of the most favoured customer clauses, a price change in the spot market or a new discount offer. We propose certainty-equivalent heuristics and evaluate the regret of using them. We use our model for three bidding events of a large manufacturing company. The results show that considering most favored customer clauses in supplier offers may create substantial savings that may surpass the savings from regular discount offers
Indentation of a free beam resting on an elastic substrate with an internal lengthscale
The plane strain problem of a slender and weightless beam-plate loaded by a transversal point force in unilateral contact with a couple stress elastic foundation is investigated. The study aims to explore the consequences of the material internal lengthscale on the contact mechanics. In particular, compatibility between the beam and the foundation surface demands that both displacement and rotation match along the contact line. To this aim, couple tractions are exchanged besides the traditional contact pressure until separation between the beam and the foundation occurs. The problem is formulated making use of the Green's functions for a point force and a point couple acting atop of a couple stress elastic half-plane. A pair of coupled integral equations is thus derived, that governs the distribution of contact pressure and couple tractions, with one of them being immediately solved to provide an explicit relation between the two unknowns. In this sense, we retrieve the concept of a mechanically equivalent action, as it is the case of the Kirchhoff shear for plates. The remaining integral equation sets a cubic eigenvalue problem, whose linear term accounts for the microstructure. Its numerical solution is sought by expanding the equivalent contact pressure in series of Chebyshev polynomials vanishing at the contact region ends points, namely the lift-off points, and then applying a collocation strategy. The contact length, the distributions of contact pressure and couple tractions under the beam and the shearing force and bending moment along the beam are then obtained as a function of the material characteristic length. Results clearly indicate that accounting for the material internal lengthscale is mainly realized through exchange of the couple tractions, in the lack of which results much resemble those of the classical solution. Specifically, greater contact lengths and a stronger focusing effect about the loading point are encountered, which become very significant when the contact length approaches the internal lengthscale
Theoretical power density from salinity gradients using Reverse Electrodialysis
Reverse electrodialysis (RED) is a technology to generate power from mixing waters with different salinity. The net power density (i.e. power per membrane area) is determined by 1) the membrane potential, 2) the ohmic resistance, 3) the resistance due to changing bulk concentrations, 4) the boundary layer resistance and 5) the power required to pump the feed water. Previous power density estimations often neglected the latter three terms. This paper provides a set of analytical equations to estimate the net power density obtainable from RED stacks with spacers and RED stacks with profiled membranes. With the current technology, the obtained maximum net power density is calculated at 2.7 W/m2. Higher power densities could be obtained by changing the cell design, in particular the membrane resistance and the cell length. Changing these parameters one and two orders of magnitude respectively, the calculated net power density is close to 20 W/m
High precision determination of the -evolution of the Bjorken Sum
We present a significantly improved determination of the Bjorken Sum for
0.64.8 GeV using precise new and
data taken with the CLAS detector at Jefferson Lab. A higher-twist analysis of
the -dependence of the Bjorken Sum yields the twist-4 coefficient
. This leads to the color
polarizabilities and
. The strong force coupling is determined to be
\alpha_{s}^{\overline{\mbox{ MS}}}(M_{Z}^{2})=0.1124\pm0.0061, which has an
uncertainty a factor of 1.5 smaller than earlier estimates using polarized DIS
data. This improvement makes the comparison between extracted from
polarized DIS and other techniques a valuable test of QCD.Comment: Published in Phys. Rev. D. V1: 8 pages, 3 figures. V2: Updated
references; Included threshold matching in \alpha_s evolution. Corrected a
typo on the uncertainty for \Lambda_QCD. V3: Published versio
A note on the effect of pre-slaughter transport duration on nutrient composition and fatty acid profile of broiler breast meat.
WOS: 00029493340000
A note on the effect of pre-slaughter transport duration on nutrient composition and fatty acid profile of broiler breast meat
WOS: 000294933400008The aim of this study was to investigate the influence of pre-slaughter transport duration, as a stress factor, on nutrient and fatty acid composition of broiler breast meat. The study was conducted on 48 breast muscles obtained from Ross broilers slaughtered at the average weight of 1.8 or 2.6 kg, 36 and 46 days old, respectively. Transport duration was 1.5 or 3 h. Heavier broilers transported for longer duration had the higher protein content, while lighter broilers gave similar results. Lower moisture but higher lipid content was observed for the long transported broilers. Fatty acid composition was significantly influenced by body weight and transport duration: a lower content of PUFA was obtained for heavier broilers. Ratios of PUFA/SFA was lower in heavier broilers. A decrease in MUFA and a lower n-3/n-6 ratio was evidenced in the meat from broilers transported for longer duration.Abalioglu Yem; Soya ve Tekstil Sanayi A.SSupported by Abalioglu Yem, Soya ve Tekstil Sanayi A.
Assessment of fetal adrenal gland enlargement in term and preterm labor cases
Background: The objective of this study was to compare the Fetal Zone Depth (FZD) of fetal adrenal gland in term and preterm labor cases.  Methods: Twenty nine preterm pregnant women at 29-36 weeks of gestation with single pregnancy admitted with the clinical diagnosis of preterm labor and the comparison group of 33 pregnant women at 37-40 weeks with term pregnancy were included in this study. FZD and Total Gland Depth (TGD) of fetal adrenal gland of the entire fetuses in sagittal plane were ultrasonographically measured and FZD/TGD ratios were calculated. Demographic and clinical features, laboratory findings and fetal adrenal gland FZD/TGD ratios were compared between the two groups.Results: No difference was found between the two groups in respect of age, number of pregnancies and delivery method (P >0.05); yet preterm birth history and duration of hospital stay were higher in preterm group (P <0.05). Fetal adrenal gland FZD/TGD ratio was statistically significantly higher in preterm group compared to the term group (55.4% ± 4.9 vs. 47.7% ± 5.6; P <0.001).Conclusion: The growth in FZ as a fetal adaptation mechanism in increased fetal stress in preterm labor cases was at a significant level. Once supported by more comprehensive studies, we think that this result would be beneficial in the prediction of preterm labor in clinical practice.
- …