Comparison of Physical-chemical and Mechanical Properties of Chlorapatite and Hydroxyapatite Plasma Sprayed Coatings

Chlorapatite can be considered a potential biomaterial for orthopaedic applications. Its use as plasma-sprayed coating could be of interest considering its thermal properties and particularly its ability to melt without decomposition unlike hydroxyapatite. Chlorapatite (ClA) was synthesized by a high-temperature ion exchange reaction starting from commercial stoichiometric hydroxyapatites (HA). The ClA powder showed similar characteristics as the original industrial HA powder, and was obtained in the monoclinic form. The HA and ClA powders were plasma-sprayed using a low-energy plasma spraying system with identical processing parameters. The coatings were characterized by physical-chemical methods, i.e. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy, including distribution mapping of the main phases detected such as amorphous calcium phosphate (ACP), oxyapatite (OA), and HA or ClA. The unexpected formation of oxyapatite in ClA coatings was assigned to a side reaction with contaminating oxygenated species (O2, H2O). ClA coatings exhibited characteristics different from HA, showing a lower content of oxyapatite and amorphous phase. Although their adhesion strength was found to be lower than that of HA coatings, their application could be an interesting alternative, offering, in particular, a larger range of spraying conditions without formation of massive impurities.This study was carried out under a MNT ERA-Net Project named NANOMED. The authors gratefully thank the Midi-Pyrénées region (MNT ERA Net Midi-Pyrénées Région, NANOMED2 project) and the Institute National Polytechnique de Toulouse (BQR INPT 2011, BIOREVE project) for supporting this research work, especially the financial support for research carried out in the CIRIMAT and the LGP laboratories (France), and the Basque government and Tratamientos Superficiales Iontech, S.A. for their financial and technical support under the IG-2007/0000381 grant for the development of the LEPS device and deposition of the coatings carried out in Inasmet-Tecnalia. The French industrial collaborators (TEKNIMED SA and 2PS SA) were financed by the OSEO programs

Consignment stock policy in a closed-loop supply chain

The main feature of sustainable supply Chain Management is reuse of end of life (EOL) products to reduce the environmental pollution. This paper considers the consignment stock (CS) policy for a closed-loop supply chain (CLSC). To achieve the economic goal, this study presents a multi-echelon supply chain with a single manufacturer, a single retailer and a third-party service provider. The objective is to optimize this three-level CLSC under a Stackelberg game scenario. The other objective is to identify the environmental impact of remanufacturing EOL products. In this CLSC, the manufacturer acts as the Stackelberg leader and the retailer, the third party are the followers. Under manufacturer’s leadership, the retailer and the third party acquire three different decision strategies – I, II, and III. In decision strategy I, the retailer acts as the leader and the third party acts as a follower, whereas in decision strategy II, they obtain a Nash game strategy. In the decision strategy III, they act as one unit and decide their decisions centrally. Numerical example and sensitivity analysis are used to illustrate optimal results of different decision strategies and also check the behaviour of key model-parameters. The best outcomes are found in decision strategy I. The main findings of our study show that when upper level player has more power then the supply chain gives best outcomes

Optimal product quality and pricing strategy for a two-period closed-loop supply chain with retailer variable markup

In this paper, we consider a two-period closed-loop supply chain which is comprised of a single manufacturer and a single retailer for trading a single product. At the retailer, the demand in the first period depends on the selling price, product quality and refund price, whereas in the second period, it depends on the selling price and the product quality. The retailer sets the selling prices with variable markups on the wholesale prices of the manufacturer and offers a return policy (immediate return and used product return) limited to the first period only. The immediate return is dependent on the refund price and the product quality, and the amount of returned used items is a fraction of the first period’s demand. The retailer sends the returned items to the manufacturer who reproduces/repairs those items and sells in the second period. We assume that the manufacturer acts as the Stackelberg leader and the retailer as the follower. We study the impacts of return policy, product quality and pricing strategy on the optimal decisions under two decision strategies (I and II). In the decision strategy I, both the players optimize their total profits over the entire selling season, whereas in the decision strategy II, they optimize each period’s profit sequentially. With the help of a numerical example we explore that the decision strategy I gives better result than the decision strategy II in terms of all decision variables except the product quality. We also investigate the effects of key model-parameters on the optimal decisions