Oligopoly newsvendor competition with reference effects

We analyze the equilibrium of a behavioral newsvendor game featuring oligopoly competition, where each newsvendor’s decision is driven by a reference effect regarding her potential profit. We find that the equilibrium order quantities are characterized by behavioral critical fractiles, where each newsvendor only accounts for the actions of competitors with smaller behavioral critical fractiles. Our result generalizes findings from recent literature on duopoly newsvendor competition with reference effects.     

ISOTHERMAL CRYSTALLIZATION: THERMAL AND OPTICAL STUDY OF PEG

In this work, the solidification process and the crystal growth kinetics of polyethylene glycol 4000 (PEG4000) and polyethylene glycol 6000 (PEG6000) (molecular average weight 4000 and 6000, respectively) were characterized by thermal optical microscopy (OM) and differential scanning calorimetry (DSC). The growth rate decreased with increasing crystallization temperature. The kinetic rate constant was lower for PEG6000 than for PEG4000 (29,300 and 32,900 K², respectively). This behavior is related to the different number of folds (folding index n) of the crystal structures. From comparison of microscopy and calorimetry measurements, the kinetic rate constant values were higher by microscopy due to different melt histories, self-nucleation, and degree of entanglement.     

Crystallization and Melting Behavior of Polypropylene in Presence of Hydrogenated Dicyclopentadiene

A study of miscibility, morphology, crystallization, and dynamic mechanical properties of polypropylene in the presence of a low-molecular-weight compound, hydrogenated dicyclopentadiene (DCPD), is described. Differential scanning calorimetry (DSC), optical microscopy (OM), and dynamic mechanical analysis (DMA) were used for this purpose. The blends exhibit composition-dependent melting point depression and reduced degree of crystallinity. Isothermal crystallization measurements show that the crystallization takes place at a lower temperature with an increase in crystallization half time with respect to pristine PP. This indicates retardation in crystallization of PP in the blends. The observed changes in the melting and crystallization behaviors are ascribed to the miscibility of the two components. The interaction parameter estimated using the Flory–Huggins equation shows negative values, suggesting the presence of strong specific interaction between PP and DCPD.     

矿区农田土壤砷污染的可见-近红外反射光谱分析研究

利用在实验室获取的矿区农田土壤可见-近红外反射光谱与土壤As污染浓度、Fe和有机质含量数据构建了As和Fe浓度及有机质含量的PCR与PLSR预测模型;为提高模型的稳定性和预测能力,对原始光谱数据进行了预处理即,一和二阶微分(F/SD)、基线校正(B)、变量标准规一化(SNV)、多次散射校正(MSC)和连续统去除(CR)。研究表明：变量标准规一化(SNV)、多次散射校正(MSC)和连续统去除(CR)分别对As, Fe和OM的PCR模型的预测能力有明显的改善(各PCR模型的因子数、相对RMSEP和R2分别5,0.304 0,0.368 5;3,0.144 3,0.476 2和3,0.171 2,0.408 4)。预测As和Fe浓度及有机质含量的最优PCR模型使用了一些共同的波段：450, 1 000, 1 400, 1 900, 2 050, 2 200, 2 250, 2 400和2 470 nm。因此,可以通过遥感技术来检测土壤污染物浓度及其他物质含量,从而为土壤环境质量的遥感监测提供参考。     

Microanalysis of blue pigments from the Ptolemaic temple of Hathor (Thebes), Upper Egypt: a case study

The aim of the present work was to characterize blue pigment samples collected from the Ptolemaic temple of Hathor (Thebes), the western bank of Luxor, Upper Egypt. The characterization of the examined pigments was carried out by means of optical microscopy, scanning electron microscopy equipped with an energy dispersive X‐ray detector, micro X‐ray fluorescence spectrometry and Fourier transform infrared spectroscopy. On the basis of the chemical composition and microstructure of the samples, the blue pigments were identified as Egyptian blue (cuprorivaite, CaCuSi₄O₁₀). Moreover, the micro X‐ray fluorescence analysis revealed significant quantities of lead in the glass phase suggesting that a leaded bronze scrap was used to produce the pigment. The optical examination of the paint layers showed that the pigments were applied on a thin layer consisting of gypsum (CaSO₄?2H₂O) and dolomite (CaMg(CO₃)₂). In addition, some pigment samples showed discoloration mainly in the form of green and black hues. The obtained results helped in improving our knowledge about some painting materials used during the Ptolemaic era of ancient Egypt. Copyright © 2012 John Wiley & Sons, Ltd.     

On the effect of a variation of the force field, spatial boundary condition and size of the QM region in QM/MM MD simulations

During the past years, the use of combined quantum-classical, QM/MM, methods for the study of complex biomolecular processes, such as enzymatic reactions and photocycles, has increased considerably. The quality of the results obtained from QM/MM calculations is largely dependent on five aspects to be considered when setting up a molecular model: the QM Hamiltonian, the MM Hamiltonian or force field, the boundary and coupling between the QM and MM regions, the size of the QM region and the boundary condition for the MM region. In this study, we systematically investigate the influence of a variation of the molecular mechanics force field and the size of the QM region in QM/MM MD simulations on properties of the photoactive part of the blue light photoreceptor protein AppA. For comparison, we additionally performed classical MD simulations and studied the effect of a variation of the type of spatial boundary condition. The classical boundary conditions and the force field used in a QM/MM MD simulation are shown to have non-neglegible effects upon the structural and energetic properties of the protein which makes it advisable to minimize computational artifacts in QM/MM MD simulations by application of periodic boundary conditions and a thermodynamically calibrated force field. A comparison of the structural and energetic properties of MD simulations starting from two alternative, different X-ray structures for the blue light utilizing flavin protein in its dark state indicates a slight preference of the two force fields used for the so-called Anderson structure over the Jung structure.     

Influence of PCL on the epoxy workability,insights from thermal and spectroscopic analyses

Epoxy compound based on diglycidyl ether of bisphenol A (DGEBA), methyl tetrahydrophthalic anhydride (MTHPA) as hardener and 2,4,6-tris (dimethylaminomethyl) phenol (DEH 35) as catalyzer, at 100/87/5 as fixed concentration was successfully processed. Aiming workable thermoset, thermoplastic Polycaprolactone (PCL) was added at 10, 20 and 30 phr contents to the epoxy compound. Analyses of Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC) and optical microscopy (OM) were conducted in order to obtain evidences from chemical interactions, curing kinetics and phase separation. From FTIR spectra partially miscibility between Epoxy and PCL can be assumed, mainly due to the hydrogen bonding between PCL carbonyl and epoxy hydroxyl, whereas after reaching epoxy's solubility limit PCL segregates and it is suggested separated phases take place through spinodal decomposition (Kinloch et al., 1994) [1] and nucleation and growth (NG) mechanisms which depend on temperature and raw material concentrations, as illustrated in OM images. Curing kinetics followed through released heat during DSC scans, indicated decreased crosslinking density upon PCL addition, as also lower Tg related to neat epoxy. Overcoming epoxy brittle fracture, rough surface fracture images with toughening character were captured from epoxy/PCL. Evidences of workable epoxy/PCL compounds are provided and related results presented in this work offer reliable tools to determine the exact aimed degree of crosslinking widening processing window to desired application.     

高均一性聚丙烯/炭黑薄膜的制备及炭黑分散性的定量表征

采用熔融共混-母粒稀释技术,辅以高效动态混合器制备了炭黑含量为2.2%与3.3%的两种聚丙烯/炭黑薄膜.基于扫描电镜(SEM)与光学显微镜(OM)图像,首次利用Image J图像分析软件定量表征了炭黑在薄膜中的分散与分布.SEM分析结果表明,炭黑含量为2.2%的膜中粒子的平均面积为0.220 μm2,且面积严格服从指数...     

Morphology of homogeneous copolymers of ethene and 1-octene. I. Influence of thermal history on morphology

The morphology of homogeneous copolymers of ethene and 1-octene synthesized using a V-based Ziegler-Natta catalyst was studied as a function of the short chain branching content (SCBC) and the molar mass. Linear polyethylenes (LPE) were used as reference material. For the linear samples an increase in molar mass results in an increase of the long period and the crystalline lamella thickness. A decrease of cooling rate results in an increase of the melting temperature, the long period and the crystalline lamella thickness and an evolution from spherulitic structures to perfectly stacked lamellae. For the branched samples, increasing the SCBC results in a decrease of the melting and the crystallization temperature, crystallinity, spherulite radius, the long period, and the crystalline lamella thickness. The two latter tend to a limiting value on reaching a SCBC of 20CH₃/1000C. On the other hand, an increase of the a axis and to a lesser extent the b axis of the unit cell is observed. Decreasing the cooling rate affects only the crystallinity of the least branched samples. Furthermore decreasing the cooling rate results in smaller spherulites, has a minor influence on the lamellar parameters and reduces the dimensions of the basal plane of the unit cell. Increasing the molar mass of the branched samples results in a drop of the crystallinity, a deterioration of the superstructure, enlarges the amorphous layer thickness and the dimensions of the basal plane. All these observations can be accounted for by the different crystallization regimes being applicable when different molar masses, SCBC and cooling rates are used. © 1997 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 35: 2689–2713, 1997