Applied Mechanics and Materials Vols. 110-116

Abstract: We employ numerical simulations to investigate the breakup of droplets in micro-and nanoscale T junctions which are used to produce small droplets from a large droplet. A Volume Of Fluid (VOF) method was used and for verifying the accuracy of simulation the results compared with two analytical researches. Our results reveal that breakup time and breakup length of the droplets play important roles in handling these systems optimally. Our results also indicate that for nanoscale T-junctions by increasing the capillary number the performance increases while for the micro-scale systems there is a specific capillary number for which the system is in its optimum condition.

Abstract: Steady, two dimensional mixed convection laminar boundary layer flow of incompressible nanofluid along a permeable vertical semi-infinite flat plate with magnetic field effects has been investigated numerically. The resulting govering equations (obtained from the boussinesq) with associated boundary conditions are solved, using a robust, extensively validated, Galerkin Finite Element Method for different types of spherical shaped metal oxide nanoparticles with two different ratios of the nanolayer thickness to the original particle radius (0.02 or 0.1). The effects of the parameters governing the problems are discussed and shown graphically. The present study is of immediate interest in next-generation solar film collectors, heat exchangers technology, material processing exploiting vertical surfaces and all those processes which are highly affected with heat transfer.

Abstract: In this article a model to describe relation between AFM cantilever’s deformation and force (as a force transducer) is developed. Furthermore a state space model is used to find suitable feedback control. A model which relates force and deformation is described. To verify a Finite element simulation is applied and a control algorithm for manipulation purpose is found. Moreover based on nature of the process control system is designed. Due to recent developments in AFM nanorobot applications in biotechnology and manufacturing nanostructures, understanding of cantilever’s response and process control have received great importance.

Abstract: This paper was removed due to double publication.

Abstract: Constitutive relationship of metallic rubber was nonlinear. Considering the constitutive relationship’s complication and BP neural net’s good ability to dispose of nonlinearity, it was necessary that constitutive relationship of metallic rubber on basis of BP neural net was studied. In this paper, coefficients of constitutive relationship for metallic rubber were studied and trained by BP neural net for the two conditions, in which shape factor is only various, density and shape factor are both various, and then coefficients of constitutive relationship were obtained. Coefficients from net prediction were compared with coefficients from experimental data fitted, and they had better consistence. It was proved that prediction for constitutive relationship of metallic rubber by BP neural net was reasonable for the two conditions, in which shape factor is only various, density and shape factor are both various.

Abstract: The strategic design and operation of outbound logistics network in an automotive manufacturing supply chain is directly related with the competitive strategy adopted by the firm. We discuss here an outbound logistics network model with four echelons and flexible delivery modes by incorporating cross-dock facility in the network. The paper aims to achieve a minimum total logistics cost for flexible delivery modes adopted in the network. The mathematical model is formulated as a mixed integer programming model and solved by using a hybrid algorithm named co-evolutionary immune-particle swarm optimization with penetrated hyper-mutation (COIPSO-PHM). The proposed model is combinatorial in nature owing to varying problem instances. The proposed solution methodology is tested on a sample data set mimicking the real life situation and the results are found to be satisfactory.

Abstract: Geldart Type-D particles are often associated with poor fluidization characteristics due to their large sizes and higher densities. This paper reports the hydrodynamics of various Geldart Type-D particles when fluidized in a swirling fluidized bed (SFB). Four different sizes of particles ranging from 3.85 mm to 9.84 mm with respective densities ranging from 840 kg/m3 to 1200 kg/m3 were used as bed material to study the effect of various bed weights (500 gram to 2000 gram) and centre bodies (cone and cylinder) for superficial velocities up to 6 m/s. The performance of the SFB was assessed in terms of pressure drop values, minimum fluidization velocity, Umf and fluidization quality by physical observation on regimes of operation. The swirling fluidized bed showed excellent capability in fluidizing Geldart Type-D particles in contrast to the conventional fluidized beds. The bed pressure drop of increased with superficial velocity after minimum fluidization as a result of increasing centrifugal bed weight. It was also found that the particle size and centre body strongly influence the bed hydrodynamics.

Abstract: In this paper, flow characteristics of water-based Al₂O₃ nanofluids according to nanoparticles shape are experimentally investigated in fully developed laminar flow regime. Al₂O₃ nanofluids of 0.3 Vol. % with sphere-, rod-, blade-, platelet-and brick-shaped nanoparticles are manufactured by the two-step method. Nanoparticles shape dispersed in base fluid are also checked using TEM image. Zeta potential and sedimentation are measured to examine suspension and dispersion characteristics of Al₂O₃ nanofluids with nanoparticles of various shapes. Based on the experimental results, it is found that the pressure drop of Al₂O₃ nanofluids strongly depends on the shape of nanoparticles at the fixed volume fraction of 0.3%. We experimentally show that the pressure drop characteristics of Al₂O₃ nanofluids can be explained by both the surface area per unit mass and the size of nanoparticles which are related with the shape of nanoparticles.

Abstract: A pulsed laser/plasma hybrid deposition method has been developed to produce the diamond-like carbon (DLC) film at atmospheric pressure in this work. A plasma torch was used to heat up the carbon particles which were simultaneously ablated by a pulsed laser, thus the kinetic energy of the carbon particle can be increased to form the carbon atoms with amorphous bonding structure of the DLC film. The influences of the plasma flow have been examined at various inlet pressures. According to the experimental results of the carbon film inspected by the Raman spectroscopy, it reveals that the intensity ratio of the D-band to G-band of the carbon film can be reduced to 0.5 by the implementation of plasma flow. Therefore the DLC film was solidly formed. The adhesive strength of the DLC film was also characterized by the scratch test, it can be found that the critical loading of the film on the iron substrate is up to 19 N.

Abstract: Many clients and plasma arc thermal cutting devices providers deal with the question which technological factor in adjustment process of cutting has the greatest influence on the final product quality. Many researchers and teachers deal with this issue during lecturing these knowledges for university students. The article presents the design and evaluation of plasma arc cutting technological process. Influence of technological factors on roughness parameters Ra of the steel surface ISO Fe510 have been evaluated using planned experiments. Using factor experiment, the significance of the four process factors: plasma burner feed speed, plasma gas pressure, nozzle diameter, distance between nozzle mouth and material have been observed. Regression models obtained by multiple linear regression indicates the quality level as observed factors function.