In this work we present a multiobjective location routing problem and solve it with a multiobjective metaheuristic procedure. In this type of problem, we have to locate some plants within a set of possible locations to meet the demands of a number of clients with multiple objectives. This type of model is used to solve a problem with real data in the region of Andalusia (Spain). Thus, we study the location of two incineration plants for the disposal of solid animal waste from some preestablished locations in Andalusia, and design the routes to serve the different slaughterhouses in this region. This must be done while taking into account certain economic objectives (start-up, maintenance, and transport costs) and social objectives (social rejection by towns on the truck routes, maximum risk as an equity criterion, and the negative implications for towns close to the plant). 相似文献
CdS nanoparticles were coated on the side wall of multiwalled carbon nanotubes (MWCNTs) by a wet chemical synthesis approach via noncovalent functionalization of MWCNTs with poly(diallyldimethylammonium chloride) (PDDA). The as-prepared material was characterized by X-ray diffraction (XRD), UV–vis absorption, fluorescence and transmission electron microscopy (TEM). The results indicated that CdS nanoparticles were uniformly coated on the surface of MWCNTs. Third-order optical nonlinearity of the as-prepared material was studied with the Z-scan technique with picosecond laser pulses at 532 nm. The Z-scan curve revealed that CdS nanoparticle-modified MWCNTs exhibited negative nonlinear refraction index and positive absorption coefficient. The real part and imaginary part of the third-order nonlinear susceptibility χ(3) were calculated to be −4.9 × 10−12 and 6.8 × 10−13 esu, respectively. 相似文献
Monodispersed cubic platinum (Pt) nanocrystals with an average size of approximately 10 nm were prepared by a reduction method with cetyltrimethylammonium bromide (CTAB) serving as steric stabilizer. The resulting Pt nanocrystals exhibit a peroxidase-like activity and catalyze the H2O2-mediated oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) to produce two colored products with high catalytic activity. The color-generating activity of this system may be influenced by several factors, and we examined several factors to optimize this colorimetric system including buffer types, pH, and concentrations of both H2O2 and Pt nanocrystals. The effect of agglomeration of Pt nanocrystals was also investigated, and we find that agglomeration of Pt nanocrystals in aqueous solution distinctly affects Pt nanocrystals catalytic activity. We attribute the catalytic activity of Pt nanocrystals to their acceleration of the electron-transfer process and the consequent facilitation of radical generation. 相似文献
A simple CE method for simultaneous determination of glyphosate and its metabolites (i.e. aminomethylphosphonic acid, glyoxylate, sarcosine and formaldehyde) in plants is reported here. A BGE of pH 7.5, 10% ACN, 7.5 mM phthalate, containing 0.75 mM hexadecyltrimethylammonium bromide as an electro‐osmotic flow modifier, an applied voltage of –20 kV and absorptiometric monitoring at 220 nm were the optimal chemical and instrumental parameters. The method, with development time 20 min, shows linear calibrations within the range 5–500 μg/mL (for all target analytes) with correlation coefficients between 0.999 and 0.998. It has been validated by application to samples of Lolium spp. The electroinjection mode hinders most interferents to enter the capillary, thus providing a clean electropherogram and making unnecessary long sample‐preparation steps. 相似文献
BL Lac object S5 2007+777 has been classified as a HYMOR (Hybrid Morphology radio source) for its hybrid FR I and FR II radio morphology. It is one of four BL Lac objects with a kpc scale extended X-ray jet. In this paper, we searched the unpublished European VLBI Network (EVN) archived high resolution data for this source, and present the high resolution radio structure. The EVN images all show a core-jet structure in 1.6, 5 and 8 GHz. In combination with the VLA data in the literature, we found position angle differences (ΔPA) of about 10°–20° between pc and kpc scale jet structures. The brightness temperature estimated from multi-band EVN images are around 1011.2–1011.8 K, from which the Doppler factor ranges from 3.2 to 12.0. We found significant flux variations of the radio core in 1.6 and 5 GHz, from which we derived the variability in brightness temperature Tvar to be 1013.6 K and 1014.0 K, corresponding to the Doppler factors of 9.3 and 12.4, respectively.
A warm standby n-system with operational and repair times following phase-type distributions is considered. The online unit goes through degradating levels, determined by inspections. Two types of repairs are performed, preventive and corrective, depending on the degradation level. The standby units undergo corrective repair. This systems is governed by a level-dependent-quasi-birth-and-death proces (LDQBD process), whose generator is constructed. The availability, rate of occurrence of failures, and other quantities of interest are calculated. A numerical example including an optimization problem and illustrating the calculations is presented. This system extend other previously studied in the literature. 相似文献