We present a new development of digital off-axis (OA) holography for determining the instantaneous solid particle positions in a flow. This holographic imaging method uses a CCD camera for the simultaneous digital recording of two views of digital Fresnel OA holograms on the same support. The reconstruction is obtained numerically. The method provides two orthogonal views of the same flow area of interest at the same instant. It helps to overcome the depth of focus problem existing for the particle image reconstructions and that is inherent to the method. This method has the advantage of being simpler than the methods presently available, and it does not suffer from the flaws of in-line holographic configuration. Furthermore it is completely digital and thus avoids the cumbersome analysis following hologram recording. Digital holograms and digital reconstructions are obtained for solid particles of 200 mum moving into a stirred flow cell of 5 cm(3).

Photo-plates used in classical holography have several advantages, mainly a high resolution and the ability to overlap several holograms. Conversely, they suffer from chemical processing and delays in getting the useful signal. In contrast to film holography, digital holography offers quick and easy access to the desired information but suffers from the low resolution of the CCD sensors and their small detecting areas. This is why many holographers were limited to the in-line scheme, because of its simplicity and ability to overcome this resolution problem. But it still suffers from several problems when recording particles such as depth of focus, superposition of twin images and others. This is why, in spite of a more complex optical arrangement, we propose an appropriate off-axis scheme and a theoretical formulation that enables us to record simultaneously two holograms on the same CCD sensor from two angle views using a single reference beam. Furthermore, such a scheme, simpler than other off-axis proposals, provides spatially separate reconstruction of the two views and overcomes the above cited problems. As the aim of our development is to measure the influence of concentration of solid particles on their velocity for mixing flows, we show here examples without extended analysis.

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In this study, turning operations on polyamide PA66 with cemented carbide insert, were organized according to the L27 Taguchi design whose objective is the analysis of the cutting parameters on the output parameters (Surface roughness and cutting force), as well as on the calculated parameter (material removal rate (Q)). The results revealed that surface roughness is highly impacted by the feed rate, which accounts for more than 68% of the variance, followed by the cutting speed and finally the depth of cut. With respect to cutting force, depth of cut and feed rate have emerged as the most important terms.A mathematical model is then created to predict the surface roughness and cutting force. Finally, the optimal cutting regime leading to good surface quality with less cutting force and maximum productivity was examinedusing two multi criteria optimization methods namely PCA and PCA coupled with TOPSIS. The total desirability function was used as a decision criterion for evaluating the two optimization methods. The results demonstrate the potential superiority of the PCA-TOPSIS method over the PCA method.

The present paper investigates the cutting parameters pertaining to the turning of X2CrNi18-09 austenitic stainless steel that are studied and optimized using both RSM and desirability approaches. The cutting tool inserts used are the CVD coated carbide. The cutting speed, the feed rate and the depth of cut represent the main machining parameters considered. Their influence on the surface roughness and the cutting force are further investigated using the ANOVA method. The results obtained lead to conclude that the feed rate is the surface roughness highest influencing parameter with a contribution of 89.69%.The depth of cut and the feed rate are further identified as the most important parameters affecting the cutting force with contributions of 46.46% and 39.04% respectively. The quadratic mathematical models presenting the progression of the surface roughness and the cutting force and based on the machining parameters considered (cutting speed, feed rate and depth of cut) were obtained through the application of the RSM method. They are presented and compared to the experimental results. Good agreement is found between the two sections of the investigation. Furthermore, the flank wear of the CVD-coated carbide tool (GC2015) is found to increase with both cutting speed and cutting time. A higher tool life represented by t=44min is observed at cutting speed, feed rate and depth of cut of 280m/min,0.08mm/rev and 0.2mm respectively. Moreover and at low cutting speeds, the formation of micro weld is noticed and leads to an alteration of the surface roughness of the work piece. Finally, optimizing the machining parameters with the objective of achieving an improved surface roughness was accomplished through the application of the Desirability Function approach. This enabled to finding out the optimal parameters for maximal material removal rate and best surface quality for a cutting speed of 350m/min, a feed rate of 0.088 mm/rev and a depth of cut of 0.9mm.