A dynamic vehicle routing problem with multiple delivery routes

This paper considers a vehicle routing problem where each vehicle performs delivery operations over multiple routes during its workday and where new customer requests occur dynamically. The proposed methodology for addressing the problem is based on an adaptive large neighborhood search heuristic, previously developed for the static version of the problem. In the dynamic case, multiple possible scenarios for the occurrence of future requests are considered to decide about the opportunity to include a new request into the current solution. It is worth noting that the real-time decision is about the acceptance of the new request, not about its service which can only take place in some future routes (a delivery route being closed as soon as a vehicle departs from the depot). In the computational results, a comparison is provided with a myopic approach which does not consider scenarios of future requests.     

Radiation synthesis of poly[(dimethylaminoethyl methacrylate)-co-(ethyleneglycol dimethacrylate)] hydrogels and its application as a carrier for anticancer delivery

The use of hydrogels as carriers for anticancer delivery has been a subject of significant recent research. In our recent work, we have shown that diffusion-controlled delivery of flutamide from hydrogels containing poly (dimethylaminoethyl methacrylate (DMAEMA)/ethyleneglycol dimethacrylate (EGDMA)) can be possible and controlled by the three-dimensional structure. Hydrogels based essentially on dimethylaminoethyl methacrylate and different ratios of ethyleneglycol dimethacrylate monomers were synthesized using gamma radiation copolymerization. The influence of copolymer composition and pH value of the surrounding medium on swelling behavior into the glassy polymer were discussed. The results showed that the ratio of EGDMA in the comonomer feeding solution has a great effect on the gel fraction and water content in the final hydrogel. In this regard, it was observed that the increase of EGDMA ratio decreased these properties. The ability of the prepared copolymer to be used as drug carrier for anticancer drug-delivery system was estimated using flutamide as a model drug. In vitro drug-release studies in different buffer solutions show that the basic parameters affecting the drug release behavior of hydrogel are the pH of the solution and DMAEMA content of hydrogel.     

Novel polydentate phosphonic acids: Protonation and stability constants of complexes with Fe(III) and Cu(II) in aqueous medium

The acido‐basic and the complexation properties of di‐, tri‐, and tetra‐phosphonic acids (H₆L1, H₈L2, and H₁₀L3) toward Fe(III) and Cu(II) were determined by potentiometric titration in aqueous media at 25.0 ± 0.1°C with constant ionic strength (0.1 M, NaClO₄). We have determined six, ten, and eight pK_a values for the di, tri, and tetra‐phosphonic acids, respectively. In acidic conditions, e.g., 0 ≤ pH ≤ 5; iron and copper presented a high affinity toward these ligands to give complex species. With the ligand H₁₀L3, [FeL3H₇], and [CuL3H₆]²⁻ were easily obtained at pH 1.8 and 2.7, respectively. We have determined ten stability constants for the H₁₀L3/Fe system and nine for the H₁₀L3/Cu one; six and four in the cases of H₈L2/Fe and H₈L2/Cu systems, respectively. Finally, five stability constants were calculated for the H₆L1/Fe system and four for the H₆L1/Cu one. We have not observed any insoluble species in these complexes in acidic medium as well as in alkaline solutions. © 2010 Wiley Periodicals, Inc. Heteroatom Chem 21:51–62, 2010; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20575     

Easily attainable new approach to mass yield ferrocenyl Schiff base and different metal complexes of ferrocenyl Schiff base through convenient ultrasonication‐solvothermal method

A new alternative approach with crucial mass yield and high reaction rates is proposed for the synthesis of ferrocenyl Schiff bases using an ultrasonication‐solvothermal method. Equimolar condensation of ferrocenecarboxaldehyde and 2‐aminophenol interact with each other, giving 1‐(1‐[2‐hydroxyphenyl‐2‐imino]methyl)‐ferrocene (FcOH). Furthermore, this ligand forms 1:1 complexes with cobalt(II), nickel(II), copper(II), and palladium(II) ions. From the different spectral data, it is found that metal ions coordinate with ligands through the azomethine group and the deprotonated oxygen of the phenol groups. Moreover, FcOH and their complexes were characterized by elemental analysis, Fourier transform infrared, ¹H nuclear magnetic resonance, and UV‐visible spectrophotometry. The spectral data of FcOH and its metal complexes were discussed in connection with the structural changes due to complexation. Meanwhile, the information about geometric structures can be concluded from the electronic spectra and the magnetic moments. Plainly, electron spin resonance spectra of the Cu(II) complex revealed d_x2?y2 as a ground state, suggesting a square planar geometry around the Cu(II) center. The direct optical band gap energy E_g values of cobalt, nickel, copper, and palladium complexes of FcOH are found to be 3.7, 3.9, 4.6, and 3.65 eV, respectively. 1‐(1‐[2‐Hydroxyphenyl‐2‐imino]methyl)‐ferrocene and its metal complexes were screened for antibacterial activity. The results depict that the metal complexes were found to be more strongly antibacterial than the guardian Schiff base ligand (FcOH) against one or more bacterial species. The minimum inhibitory concentrations of antimicrobial properties of the purified compound were determined using the broth microdilution method.     

Kinetics of the reaction of sodium arylthiolates with nitro-carboxybenzyl halide derivatives

The rate constants for the reactions of 4-halomethyl-3-nitrobenzoic acids, the nonnitro derivatives, and their ethyl esters with arylthiolates were measured at different temperatures. It was found that the retardation in rate constants compared to benzyl halides is due to the electrostatic repulsion between the electronegative substituents (COO⁻ and/or NO₂) in the substrates and thiolate ions. Good correlations between log k₂ values of the acids and carbon basicities of thiolates were found while log k₂ values of the esters show good straight lines with Hammett σ constants, pk_a, and carbon basicities of arylthiolates. © 1996 John Wiley & Sons Inc     

Adducts of coordination compounds—12: New hydrogen dinitrates and their structures

The new compounds trans-[Ru(pyr)₄Cl₂[H(ONO₂)₂] and [C₁₃H₉NH][H(ONO₂)₂] have been characterised (where pyr is pyridi     

Microcalorimetric studies of dodecacarbonyl(diiron)ruthenium and dodecacarbonyl(iron)diruthenium. Enthalpy contribution of heterometallic metal—metal bonds

Microcalorimetic measurements at 520–550 K of the heats of thermal decomposition of Fe₂Ru(CO)₁₂, FeRu₂(CO)₁₂ and Ru₃(CO)₁₂ lead to values of the standard enthalphy of formation (ΔH^o_f, c/kJ mol^-1) as follows: Fe₂Ru(CO)₁₂  (1820 ± 14); FeRu₂(CO)₁₂  (1891 ± 16); Ru₃(CO)₁₂  (1903 ± 18). Enthalpies of sublimation are estimated and the ironruthenium bond enthalpy contribution is derived as E(FeRu)  (95 ± 20) kJ mol^-1.     

Influence of specific surface area of pyrogenic silicas on their heat of immersion in water and on their surface properties assessed using inverse gas chromatography

The heat of immersion and the surface properties of pyrogenic silicas were examined using microcalorimetry and inverse gas chromatography at finite concentration (FC-IGC). The microcalorimetric measurements showed a regular decrease of the heat of immersion, in water, per area unit with an increase in the surface areas. The desorption isotherms were established using FC-IGC. It is observed that BET constant value goes through a minimum, whereas the shapes of distribution function of the adsorption energies of isopropanol are changing. All results could be interpreted using a model of formation of the pyrogenic silica in the flame, which explains the change of surface functionality and geometry occurring around 200 m2/g.     

Lignin-Phenylhydrazone as a Corrosion Inhibitor of API X52 Carbon Steel in 3.5% NaCl and 0.1 mol/L HCl Medium

The best alternative to fight against corrosion is the use of an inhibitor, the purpose of this work is the formulation of a new biomass-based molecule against corrosion of carbon steel. Lignin was extracted using the Kraft process and phenylhydrazine molecules have been scratched. The influence of the lignin-phenylhydrazone(LP) on the corrosion of carbon steel in salt and the acidic medium was studied by the polarization resistance, the potentiodynamic polarization, and the electrochemical impedance spectroscopy. The results of these tests reveal that the behavior of the inhi-bitor is a mixed type. The adsorption mechanism of the inhibitor follows the Langmuir isothermal model. Gibbs energy shows that the process of inhibition of carbon steel is spontaneous. The SEM confirms that the inhibitor reduces the corrosion of the steel and stops the corrosion pitting phenomenon. The modified lignin shown as a good corrosion inhibitor in acid medium is highly saline with an efficiency> 96%.