An adaptive large neighborhood search heuristic for the Pollution-Routing Problem

The Pollution-Routing Problem (PRP) is a recently introduced extension of the classical Vehicle Routing Problem with Time Windows which consists of routing a number of vehicles to serve a set of customers, and determining their speed on each route segment so as to minimize a function comprising fuel, emission and driver costs. This paper presents an adaptive large neighborhood search for the PRP. Results of extensive computational experimentation confirm the efficiency of the algorithm.     

Comment on ＇Electronic Properties of Red P-Type T12S5 Single Crystals＇

Recently, Gamal et al. [Chin. Phys. Left. 22 （2005） 1530] reported the results of electrical conductivity, Hall effect and thermoelectric measurements on p-type T12S5 single crystals. From the experimental data for the temperature dependence of differential thermoelectric power, G amal et al. determined the values of 2.66 × 10^-41 kg and 2.50 × 10^-41 kg, respectively, for the effective masses of electrons and holes in p-type T12S5, which are about ten orders of magnitude smaller than the free electron mass （9.11 × 10^-31 kg）. We argue that the anomalously small values obtained for the effective mass of charge carriers in T12S5 have no physical significance.     

Two-Parametric Extension of h-Deformation of GL(1|1)

The two-parametric quantum deformation of the algebra of coordinate functions on the supergroup GL(1|1) via a contraction of GL_p,q(1|1) is presented. Related differential calculus on the quantum superplane is introduced.     

A new antibacterial diterpene from the roots of Salvia caespitosa

From the roots of Saliva caespitosa Montbret and Aucher ex. Bentham a new diterpene 6beta-hydroxyisopimaric acid (1) has been isolated together with four known diterpenes, one new triterpenoid, 3-acetylvergatic acid (2), as well as five known triterpenoids, two steroids and a flavone. The structures of the compounds were established by spectroscopic analyses. The isolated compounds were tested against standard bacterial strains. Only the new diterpene, 6beta-hydroxyisopimaric acid has strong activity (MIC 9 microg/ml) against S. aureus and (MIC 18 microg/ml) against S. epidermidis as well as against B. subtilis (MIC 9 microg/ml).     

Isocyanate formation in the catalytic reaction of CO + NO on Pd(111): an in situ infrared spectroscopic study at elevated pressures

The catalytic CO + NO reaction to form CO2, N2, and N2O has been studied on a Pd(111) surface at pressures up to 240 mbar using in situ polarization modulation infrared reflection absorption spectroscopy (PM-IRAS). At 240 mbar, for a pressure ratio of PCO:PNO = 3:2 and under reaction conditions, besides adsorbed CO, the formation of isocyanate (-NCO) was observed. Once produced at 500-625 K, the isocyanate species was stable within the entire temperature range studied (300-625 K). On the other hand, its formation required a total CO + NO pressure of at least 0.6 mbar, illustrating the importance of in situ infrared experiments under high-pressure conditions. The significance of the isocyanate formation for the CO + NO reaction on Pd(111) is discussed.     

Determination of the hydroxyl radical by its adduct formation with phenol and liquid chromatography/electrochemical detection

An HPLC-ECD method is described for the indirect determination of the hydroxyl (OH) radical. Fenton's reaction is used to produce OH, which simultaneously attacks phenols (phenol or pyrocatechol) to form the adducts, pyrocatechol or pyrogallic acid. Thus, [OH] quantification is based on the separation and detection of pyrogallic acid and/or pyrocatechol by an isocratic HPLC-ECD method. The quantification of OH is also performed alternatively by a chronoamperometric detection in an electrochemical cell, where simultaneously formed Fe^III (Fenton's reaction) combines [Fe^II(CN)₆]⁴⁻ to produce the Prussian blue (PB) molecules (Fe₄^III[Fe^II(CN)₆]₃). Newly formed PB molecules are then immediately converted to colorless Everitts salt (K₄Fe₄^II[Fe^II(CN)₆]₃) with the reduction of the high-spin Fe^III to Fe^II at the surface of a glassy carbon electrode at +0.150 V (versus Ag/AgCl). The calculated concentration of OH during incubation (0.626 ppm) can be detected with negative errors by the HPLC-ECD (0.595 and 0.615 ppm with the errors −5.2 and −1.8%, respectively) and by the chronoamperometric method (0.552 and 0.607 ppm with the errors −11.8 and −3.0%, respectively). For the comparison of the two sets of data, HPLC-ECD method is much more promising.     

Elasticity of adsorbent beds

The practical application of adsorbents with the desired separation properties depends not only upon the adsorption characteristics of the material but also upon the mechanical properties of the packed bed. The packed bed, the vessel surrounding the bed and any internal structure that supports the bed are subjected to both static and cyclic loads during an adsorption process. In order to properly design the vessel and its internal structure, the bulk mechanical properties (most particularly the elastic properties) of the adsorbent bed must be known. The primary focus of this study was to determine the elastic properties of adsorbent beds packed with activated alumina, synthetic molecular sieve 13X or natural zeolite clinoptilolite. The bulk modulus of elasticity was found to be a linear function of applied stress for each of these materials in a range of stresses lower than the bulk crush strength. The Poisson’s ratio for the packed bed was also deduced from these results.     

Global Numerical Model for the Assessment of the Effect of Geometry and Operation Conditions on Insert and Orifice Region Plasmas of a Thermionic Hollow Cathode Electron Source

Thermionic hollow cathodes have been widely used in wide variety of areas such as spacecraft electric propulsion systems, material processing and lasers for more than half a century as efficient electron sources. Especially in electric propulsion systems, hollow cathodes are being used as electron sources for propellant ionization and ion beam neutralization. Moreover, it is also a promising candidate for utilization as a stand‐alone propulsion system in microsatellites or nanosatellites due to its small physical size, low power consumption and ease of operation. On the other hand, the small geometry of the typical orificed hollow cathodes makes the plasma diagnostics difficult which is why numerical studies become important for understanding the driving physical processes behind their operation, and the effects of the geometry and the operation parameters on cathode performance. In this paper, a global numerical model for the insert and orifice plasma of a hollow cathode is presented where volume averaged plasma parameters are considered for both regions. The results of this study show that the developed model can be used for designing and sizing orificed hollow cathodes as comparisons with the results of experimental and other numerical studies are in good agreement with the ones obtained from the developed model. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Modelling with the Novel INAR(1)-PTE Process

Methodology and Computing in Applied Probability - In this paper, the first-order non-negative integer-valued autoregressive process with Poisson-transmuted exponential innovations is introduced....