In this study, the dynamic analysis of Pipeline Inspection Gauge (PIG) flow control in natural gas and liquid pipeline is considered. The basic equations are differential forms of the mass and linear momentum for compressible liquid and gas flows. The fluid flow equations and a linear momentum equation of the PIG are solved simultaneously using an appropriate numerical method. Solution of these nonlinear equations results in a set of diagrams for the variations of the fluid pressure, mass flow rate of the gas and the PIG velocity through the pipeline. Comparing the results of mathematical model for the PIG with the established experimental data in a segment of Ahwaz gas pipeline shows a good agreement between the measurements and computations.

Safflower is an oil-seed crop with high quality oil that is used for producing healthy foods and painting colors. This crop has valuable petals which have a lot of uses in medicine, production of food colors and dyes for coloring fabrics, but such problem as dispersion of flowers, thorns of crops that hurt worker’s hands also lack of a suitable harvesting machine have enforced farmers to harvest petals by hand that is a hard work and non-economic. In this study a prototype machine was designed and constructed. This machine includes an engine, a radial fan with BI blades, a snout, a diffuser to separate petals from airflow and a store; all parts are assembled on a trolley to move easily in farm. This machine picks safflower petals out and intakes through snout by the fan suction power. Petals go to diffuser where they are separated from airflow then fall to the store. Velocity of airflow in the snout was determined by a fan test duct in order to design diffuser. At last three farms were harvested by this machine for economic analysis. Results show 657% increasing in amount of harvested petals by harvester machine in comparison with hand harvesting.

The market demand for machining and cutting of various plastics parts is in continuous increase. The aim of this study is to extract prediction laws for surface roughness, cutting forces and temperatures evolution during the machining of two polyethylene pipes grades (HDPE-100) and (HDPE-80). It was found that feed rate is the most prevailing factor on roughness criteria and that better surfaces are obtained during the machining of the harder HDPE-80 resin. Also, cutting speed improved surface quality for speeds up to 200 m.min-1 but the rising interface temperature caused surface damage and material rapid softening. Also, feed exponents, in mathematical models, were found to be 3 to 4 times higher than those of cutting speed and depth of cut. An increase in the cutting speed led to a gradual reduction for the 3 cutting forces components (Fr, Fa and Fv) with a dominance of the tangential force (Fv). As expected, the value of the depth of cut had a large influence on the temperature within the cutting zone. This temperature is slightly higher during the machining of HDPE-80 compared to that of HDPE-100 most probably because of hardness differences. The analysis of variance (ANOVA) was performed to check the adequacy of the mathematical models relating cutting parameters with roughness, cutting forces and global cutting zone temperature.

This paper investigates the windage power losses generated by spur gears rotating in pure air by using a computational fluid dynamics (CFD) code. The three-dimensional simulations are at first validated comparing CFD predictions with the power losses measured in similar conditions from other investigations. The volumetric flow rate which is expelled by the teeth is then analysed, and a correlation which is based on a classical approach used in turbomachinery is finally proposed which makes it possible to estimate windage losses for spur gears. It was observed that this latter approach seems satisfying since the formulation of the volumetric flow rate which is employed in the model is appropriate to each gear.

This paper synthesizes a whole of work carried out on the spiral bevel gears from quasi-static and dynamic models viewpoint. A sophisticated quasi-static model makes it possible to calculate the tooth loads, the pressures, the instant mesh stiffness, and the deflections on the flanks of spiral bevel gears. Based on these results, two three-dimensional lumped parameter dynamic models are presented. The mechanical system under consideration comprises: a spiral bevel pinion and gear connected by a time-varying non-linear mesh stiffness function, and mounted on two shafts simulated by Timoshenko’s beams supported by bearings. Two variants are considered which rely on different contact stiffness simulations: (a) using an averaged mesh stiffness function acting at the centroid of the loaded areas on tooth flanks and (b) a more local approach based on a discrete distribution of the local mesh stiffness, elements over the contact areas. A number of results are presented and commented which illustrate the interest of these dynamic models.

Thermoplastic based composites containing different weight fractions of molybdenum disulfide (MoS2) solid lubricant were developed by injection molding. Polymethyl methacrylate (PMMA) and polycarbonate (PC) were chosen for the thermoplastic matrices. In order to characterize the interfacial adhesion between the matrices and the filler, we observed the fracture morphologies of selected composites. Micrographs of the fractured surfaces showed removal of MoS2 particles by microcraking as well as the presence of voids in the case of PMMA/MoS2 composites. These observations were confirmed by complementary images obtained using the X-ray tomography. The addition of an appropriate coupling agent may improve the adhesion between the MoS2 particles and the polymer matrix. Tribological behavior of the composites was also investigated using a ball-on-flat microtribometer with a high chromium steel ball antagonist. It was found that the addition of MoS2 particles didn’t improve the tribological performance of the composite in the case of PMMA matrix unlike the case of PC matrix where the friction coefficient was considerably reduced.

Une double enceinte climatique conçue sur le principe de la méthode de la boîte chaude gardée a été mise au point afin d’étudier en laboratoire le comportement thermique et hygrique de différentes configurations de parois en bois. Le dispositif est doté d’équipements de régulation lui permettant de reproduire des sollicitations climatiques stationnaires ou dynamiques proches d’un climat réel et de suivre l’évolution des profils de température et d’humidité dans les parois testées. Dans ce travail, le suivi du comportement hygrothermique d’une paroi en ossature bois comportant des matériaux hygroscopiques et soumises à différentes conditions est rapporté. Les résultats ont montré que la capacité du dispositif à bien reproduire les conditions imposées a permis de mesurer les propriétés importantes de parois en régime permanent (résistance thermique) et transitoire (amortissement et déphasage thermique). Les essais réalisés ont également mis en évidence le comportement hygroscopique des matériaux testés.

Une étude expérimentale du séchage convectif à haute température en vapeur d’eau surchauffée et du séchage à l’air d’une particule poreuse et sphérique du bois (hêtre) est présentée. Un dispositif de macro-TG, dans lequel une particule est suspendue et continuellement pesée au cours du séchage, est utilisé. En prenant deux valeurs de la vitesse du fluide séchant (vapeur d’eau surchauffée ou air), nous avons mesuré la teneur en eau et la température du produit au cours des deux procédés de séchage. Aussi, on a montré que le bois séché en vapeur d’eau surchauffée est nettement de qualité supérieure à celle obtenue à l’air. En effet, la particule du bois séchée en vapeur d’eau surchauffée garde sa couleur naturelle alors que celle séchée à l’air noircit. Le procédé de séchage en vapeur d’eau surchauffée répond alors au mieux à l’exigence la plus demandée par les industriels qui est qualité du produit. Parmi les applications possibles de séchage de ces particules est la fabrication du bois aggloméré.