Exact and heuristic methods for a full-load,multi-terminal,vehicle scheduling problem with backhauling and time windows

The problem considered is the full-load pickup and delivery problem with time windows (PDPTW), and heterogeneous products and vehicles, where the assignment of pickup points to requests is not predetermined. The problem is first formulated as a 0-1 LP, then a hybrid algorithm is developed, which chooses dynamically between a Greedy heuristic and one based on Regret costs. A multi-level constructive heuristic that consists of three post-optimizers is presented. Two lower bounds are used to evaluate the performance of the proposed heuristics when tested on random instances and selected data from a construction company.     

Crystal and molecular structure of phenylbenzyl-1-(2,2,3-trimethylcyclopropyl)phosphine oxide

The title compound crystallizes in the orthorhombic space groupPna2₁, witha=15.576(2),b=19.134(3),c=5.693(1) Å andz=4. The structure was solved by direct methods, and refined to a finalR value of 0.059. This study confirms both the structure and stereochemistry of the title compound.     

A multi-objective heuristic approach for the casualty collection points location problem

In this paper, we formulate the casualty collection points (CCPs) location problem as a multi-objective model. We propose a minimax regret multi-objective (MRMO) formulation that follows the idea of the minimax regret concept in decision analysis. The proposed multi-objective model is to minimize the maximum per cent deviation of individual objectives from their best possible objective function value. This new multi-objective formulation can be used in other multi-objective models as well. Our specific CCP model consists of five objectives. A descent heuristic and a tabu search procedure are proposed for its solution. The procedure is illustrated on Orange County, California.     

The many-to-many location-routing problem

In this paper the many to many location routing problem is introduced, and its relationship to various problems in distribution management is emphasised. Useful mathematical formulations which can be easily extended to cater for other related problems are produced. Techniques for tackling this complex distribution problem are also outlined.     

The multi-source Weber problem with constant opening cost

A constant fixed cost of establishing a facility is introduced within the framework of minisum facility location in the continuous space. The solution method developed uses a multi-phase heuristic that first solves a discrete version of the problem by existing methods to obtain an estimate of the optimal number of facilities. Some results are presented for test problems taken from the literature and compared with best-known solutions of the multi-source Weber problem with the addition of the appropriate fixed costs.     

A perturbation heuristic for a class of location problems

A constructive heuristic which has the flexibility of perturbing the solution while guiding the search toward a better solution is developed. Interesting findings are obtained when this heuristic is tested against reputable methods on a class of uncapacitated location problems.     

Structure of 5-azauracil (C3H3N3O2) and its hydrolysis product

The title compounds cocrystallize in space groupP¯1:a=8.773(3),b=9.14(3),c=14.062(4) Å, =81.38(7), =71.76(3), =82.96(8)°,U=1055.5 ų,Z=4 (two independent molecules each of azauracil, its hydrolysis product, and water in the asymmetric unit). The structure was solved by direct methods and refined by full-matrix least-squares methods toR=0.059 for 2911 observed reflections. Unusually, the crystal contains both the parent molecule and its hydrolysis product in a hydrogen-bonded complex. The hydrogen bonding results in the formation of essentially planar layers of molecules which are held together by dispersion forces.     

The effect of voltage controlled orientation order of liquid crystals in non-acrylic polymer dispersed liquid crystals films

The nematic liquid crystals (LCs) are randomly dispersed material with random orientation order in polymer dispersed liquid crystal (PDLC) films. The LCs change their orientation from random to vertical as electric field is applied. This transformation of orientation order of nematic liquid crystals in the PDLC films is controlled by many factors operating simultaneously. For instance, some factors like the internal forces of attractions among the neighboring LC molecules, anchoring with polymeric matrix, ITO glass boundaries, and chemical structures of the materials are less studied. The learning of extent of vertical orientation of liquid crystal droplets in an electric field is essential to attain optimum electro optical properties of PDLCs. In this finding, bipolar and radial LCs droplets with random orientation have been observed in non-acrylic polymeric media. It is learned that with small increase of contents of external material, the extent of vertical orientation has been varied intensely. The extent of vertical orientation of LCs molecules increases as the contents of external non-acrylic polymeric material decreased. For this study, the orientations of LCs with respect to material type/contents, external applied force, and restoration of electric filed as hysteresis have been studied in details.     

Semi-automated continuous sample drop flow microextraction with swift preconcentration and atomic absorption spectrometry determination of lead in water and apple leaves

In this paper, we present novel developments to our recently developed method so-called “continuous sample drop flow microextraction (CSDF-ME)” technique. Previously, we showed that the CSDF-ME technique offers several advantages, including stability of extraction solvent, no need for holder device, and easy to operate. The merit of current study is to make the extraction steps faster with sample required for the analysis. The key novelty of proposed method includes usage of a solvent mixture (i.e., methanol and carbon disulfide), allowing to pump aqueous samples with a higher flow rate than the former technique which led to reduce the extraction time. Results show that the technique is cable to become faster by five times with an enrichment factor of 93 for 4.0 mL of aqueous sample. The linear range and limit of detection for Pb are found to be 0.1–6.0 and 0.03 µg L^?1, respectively. The relative standard deviation for determination of 1.0 µg L^?1 of Pb in a sample is 2.9% (n?=?5). Furthermore, the relative recoveries of the developed CSDF-ME method for Pb in tap water, mineral water, and Standard Reference Material for apple leaves (1515) are shown to be 98, 100, and 94%, respectively.     

Investigations of the reduced Redlich–Kister excess properties of 1,4-dioxane + isobutyric acid binary mixtures at temperatures from 295.15 to 313.15 K

Excess molar volumes and refractive index, molar refraction deviations and isentropic compressibility changes in 1,4-dioxane + isobutyric acid binary mixtures (from 295.15 to 313.15) K. were calculated from experimental density, refractive index and sound velocity data presented in previous work. Here, these experimental values were used to test the applicability of the correlative reduced Redlich–Kister equation as well as their corresponding relative functions which are important to reduce the effect of temperature and, consequently, to reveal the effects of different types of interactions. The results of these observations have been interpreted in terms of structural effects of the solvents. The correlating equation recently proposed by Belda, has also been applied to the present system in order to assess the validity of this equation and to give thermodynamic limiting partial molar quantities interesting to evaluate solute–solvent interaction.