The incorporation of fixed cost and multilevel capacities into the discrete and continuous single source capacitated facility location problem

In this study we investigate the single source location problem with the presence of several possible capacities and the opening (fixed) cost of a facility that is depended on the capacity used and the area where the facility is located. Mathematical models of the problem for both the discrete and the continuous cases using the Rectilinear and Euclidean distances are produced. Our aim is to find the optimal number of open facilities, their corresponding locations, and their respective capacities alongside the assignment of the customers to the open facilities in order to minimise the total fixed and transportation costs. For relatively large problems, two solution methods are proposed namely an iterative matheuristic approach and VNS-based matheuristic technique. Dataset from the literature is adapted to assess our proposed methods. To assess the performance of the proposed solution methods, the exact method is first applied to small size instances where optimal solutions can be identified or lower and upper bounds can be recorded. Results obtained by the proposed solution methods are also reported for the larger instances.

     

Anticancer effect of three pyrazole derivatives

The evaluation of the cytotoxic properties in vitro of three synthetic tripods containing pyrazole: N,N-bis[(3,5-dimethylpyrazol-1-yl)methyl]aniline (1); N,N-tetrakis[(3,5-dimethylpyrazol-1-yl)methyl]-para-phenylenediamine (2); and N,N-tetrakis-[(1,5-dimethylpyrazol-3-yl)methyl]-para-phenylenediamine (3), was examined for their cytotoxic activity on two tumor cell lines: P815 (murin mastocytoma) and Hep (human laryngeal carcinome). While the compound 2 shows a small cytotoxic activity, compounds 1 and 3 are more cytotoxic against both cell lines. However, this cytotoxicity is more pronounced against Hep cell line (IC50: 3.25 microg mL(-1) for compound 1 and 6.92 microg mL(-1) for compound 3) than P815 cell line (IC50: 17.82 microg mL(-1) for compound 1 and 37.21 microg mL(-1) for compound 3). Statistical analysis shows that the compound 1 is two- to threefold more cytotoxic than compound 3 (P < 0.05). Interestingly, the cytotoxicity induced by compound 1 against Hep cell line is more important than that induced by adriamycin used as a positive control.     

An investigation into the relationship of heuristic performance with network-resource characteristics

Constrained resource project management heuristics are analyzed and their performance is assessed related to well defined project types. Such results have shown that using the overall performance measure of a given heuristic can, in some situations, be misleading.An efficient heuristic, which combines resource and criticality factors is also proposed. Computational experiments on a set of 6120 networks varying in size from 45–666 activities, 3 resources, and under different network parameters are reported. The proposed heuristic outperforms the best existing dispatching rules in certain project classes and also on problem sets appearing in the literature.     

Inventory routing problems: a logistical overview

This paper presents an overview of Supply Chain Management while focussing on the area of Inventory Routing. We aim to provide the state-of-the-art in this area while highlighting the usefulness of the models in practice as well as their limitations. We have classified the papers based on the planning horizon employed in the models namely single period, multiperiod and infinite horizon models that are then complemented by those with stochastic demand patterns. Future research avenues that we believe to be of interest to the OR/MS community are also presented.     

Thermal study of PN thermoelectric couple by laser induced Seebeck EMF measurement

We propose in this paper an in-depth study of a method, both experimental and theoretical, for the determination of thermoelectric properties, in single, or multi-layered thermoelectric devices. We use a modulated laser beam as a heater in order to generate a thermally induced Seebeck EMF. The laser beam, line shaped, can be focused at any location along the sample surface, allowing spatially resolved measurements. Seebeck EMF measurements, associated with a versatile modeling method based on the thermal quadrupoles, allow determining sample Seebeck EMF profile. We contemplate to apply this technique to thermal and thermoelectric properties identification.     

Room-temperature diode laser photoacoustic spectroscopy near 2.3 μm

We describe results obtained with a new type of GaSb-based semiconductor distributed feedback multiple quantum well lasers operating in continuous-wave mode at room temperature and above. The lasers show good tunability both by the excitation current and the temperature from -1 °C to +60 °C (4170 to 4360 cm^-1). They operate in a high-power (more than 1 mW) single-mode regime and can be tuned without hopping in the methane and ammonia absorption spectral range of up to 15 cm^-1. Application to photoacoustic detection is also described. Potential use lies in the areas of analytical chemistry of gases and in atmospheric pollution research. PACS 82.80.Kq; 42.62.Fi; 42.55.Px     

A Tabu Search Approach for the Resource Constrained Project Scheduling Problem

An appropriate tabu search implementation is designed to solve the resource constrained project scheduling problem. This approach uses well defined move strategies and a structured neighbourhood, defines appropriate tabu status and tenure and takes account of objective function approximation to speed up the search process. A sound understanding of the problem has helped in many ways in designing and enhancing the tabu search methodology. The method uses diversification, intensification and handles infeasibility via strategic oscillation.The above methodology is tested on existing problems from the literature and also on parametrically generated problems with encouraging results. For comparison of results, optimal solutions are used in the former and lower bounds obtained by Lagrangian heuristics are used in the latter.     

Prestressed FRP and interface slip effect on interfacial stresses analysis: the new FRP sheets rigidity model

This paper presents an improved bi-material beam theory with adhesive interface and the new prestressed-fiber reinforced polymer (FRP) – model, which has been applied to the study the problem of interfacial stresses. This work explicitly considers the interfacial slip effect on the structural performance by including both the effect of adherend shear deformations and the fiber volume fraction of the prestressed laminates. This new method needs only one differential equation to determine both shear and normal interfacial stress, which is one aspect that has not been taken into account by the previous studies in the literature. A parametrical study is carried out to show the effects of some design variables, e.g., stiffness and thickness of adhesive layer and FRP plate.     

Generation and propagation of novel donut beams by a spiral phase plate: Humbert beams

The theoretical conversion of the Bessel-modulated Gaussian beam with a quadratic radial dependence by a spiral phase plate (SPP) leads us to generate a novel donut family that we called it Humbert beam. In this paper, the different theoretical tools are developed to obtain these new waves. Some numerical calculations are performed to study the transformation and the propagation of this new family by a SPP with an integer topological charge through an ABCD optical system. The present study shows also that the Humbert beam generalized the Kummer family waves.     

Numerical analysis of InGaAs–InP multiple-quantum well laser emitting at 2 {\upmu }m

Multiple-quantum well InGaAs laser structures emitting at 2  \(\upmu \) m with different barriers are modeled using commercial software that combines gain calculation with 2-D simulations of carrier transport and waveguiding. The model is calibrated using experimental results. The simulated results show a non-uniform distribution of carriers in different quantum wells with InGaAlAs barriers which affects their contribution to the gain. The carrier uniformity and a reduction in threshold current density are observed when we use an InGaAs barrier material. The quantum well number was varied from 2 to 4 in both structures and a comparison of the threshold current and its variation with temperature were investigated.