INTERNATIONAL JOURNAL OF ENGINEERING
Year:2011 | Volume:24 | Issue:2 (TRANSACTIONS B: APPLICATIONS)|Papers Count:9

VLSI circuits design allows today to consider new modes of implementation for electrical controls. However, design techniques require an adaptation effort that few designers, too accustomed to the software approach, provide. The authors of this article propose to develop a methodology to guide the electrical designers towards optimal performances of control algorithms implementation. Thus, they were based on two concepts: modular design and algorithm architecture adequation. An exemple of DTC control implemented in an ASIC circuit is presented and the results of the integration performances valid our methodology.

It is important in the design of a drying system to evaluate the sticking behaviour of the materials being dried. A new approach to the sticking issue is applied in this study by carrying out a sticking test for the liquid associated with the materials under study. It was found that the liquid bridge is responsible for the initial sticking of the materials to the contact surfaces. The colloidal material in this liquid is eventually responsible of building a sticky solid bridge during drying. The glass transition temperature for the Brewers Spent Grain (BSG) particles and the colloidal solution expelled from these particles were tested using Differential Scanning Calorimetric (DSC). However, the chopped BSG particles showed no glass transition temperature; there were an appreciable number of particles stuck to the rotary drum dryer and the sample holders during drying. The colloidal particles in the liquid bridge were filtered and concentrated through evaporation and then analysed by DSC where they showed a glass transition temperature at (-23) and (-33) oC. In addition, the associated liquid thus prepared showed a honey consistency and a sticky touch when concentrated.These two properties are indications that this colloidal material may be responsible for sticking the BSG to the steel surfaces during drying.

Plant location selection has invariably a significant impact on the performance of many companies or manufacturing systems. In this paper, a new integrated methodology is structured to solve this selection problem. Two well-known decision making methods, namely analytic hierarchical process (AHP) and VlseKriterijumska Optimizacija I Kompromisno Resenje (VIKOR), are combined in order to make the best use of information available, either implicitly or explicitly. In addition, the Delphi method is utilized to select the most influential criteria by a few experts. The aim of using the AHP is to give the weights of the selected criteria. Finally, the VIKOR method is taken into account to rank potential alternatives. Finally, an application example demonstrates the suitability of the proposed methodology.

This paper presents 2-D finite volume method for computation of viscous drag based on Reynolds-averaged Navier-Stokes (RANS) equations. Computations are performed on bare submarine hull DREA and six axisymmetric bodies of revolution with a number of length-diameter (L/D) ratios ranging from 4 to 10. Both structured and unstructured grids are used to discretize the domain around the bodies. Different turbulence models have been tested to simulate turbulent flow. The comparison of predicted results from 2-D method with published experimental/numerical results showed satisfactory conformity.

Incorporation of copper species in a silica matrix is carried out using sol-gel method. Copper ions and copper particles were chemically synthesized and incorporated in the matrix using two different copper sources of Cu (NO3)2.3H2O and copper particles. The particles of copper metallic, cuprous and cupric oxide were prepared and synthesis and characterization of copper species on the silica matrix were compared.

In this paper, the dynamic response of a three-rotor flexible coupling to the angular misalignment has been studied. The coupling is a power transmission agent between the motor and gearbox, in the power transmission system of SAG Mill (semi autogenously mill) in the Gol-e-Gohar iron ore complex in Sirjan, Iran. Degrees of freedom of the system are the model's lateral deflections and the rigid-body linear motions. The equations of motion are obtained by using the Lagrange equations through successive partial differentiation of the kinetic and potential energies. In the dynamic model, the middle rotor is considered as an eccentric flexible Jeffcott rotor. The gearbox input shaft is considered to be angularly misaligned with respect to the motor shaft. Diagrams of the amplitudes versus the frequency ratio reveal the system dynamic response to the angular misalignment.

One promising way to achieve low temperature combustion regime is using a large amount of cooled EGR. In this paper, the effect of injection timing on low temperature combustion process and emissions were investigated via three dimensional computational fluid dynamics (CFD) procedures in a DI diesel engine using high EGR rates. The results show that when increasing EGR from low levels to levels corresponding to reduced temperature combustion, soot emission after first increasing is decreased beyond 40% EGR and reaches its lowest value at 58% EGR rate. Advanced injection timing before 20.5ºCA BTDC together with applying 58% EGR leads to simultaneous reduction in NOx and soot formation compared with the base engines. The predicted values of combustion process, emissions by this CFD model at high EGR levels show a good agreement with the corresponding data in the literature.

Effects of pH, D2EHPA, CyanexÒ 272 and CyanexÒ 302 on extraction of zinc, manganese and cobalt from a Zn-Mn-Co-Cd-Ni containing solution at the room temperature was comprehensively investigated. Addition of CyanexÒ 302 indicated a left-shifting-effect on the extraction curve of zinc, a right-shifting-effect on the extraction curve of manganese and no effect on the extraction of cobalt. Addition of CyanexÒ 272 shifted all three curves to the right. Therefore, the most suitable extractant for separation of zinc from manganese was therefore 0.3-0.3 mixture of D2EHPA and CyanexÒ 302, and that for separation of manganese from cobalt was pure D2EHPA.The stoichiometric coefficient for the extraction reaction of zinc (whether using pure D2EHPA or a mixture made of D2EHPA with CyanexÒ 272 or CyanexÒ 302) was 3. It varied from 4 to 5 for manganese, when the quantity of CyanexÒ 302 dissolved in D2EHPA increased from 0 to 100%.Utilizing the above results, a two stage leaching was devised to recover zinc, manganese and cobalt from a complex solution. At the first stage, a 0.6M D2EHPA extractant could recover zinc, and a scrubbing reaction with organic: aqueous (O: A) ratio of 20: 1 could wash-out cadmium from the raffinate. In the second stage, the extracting residue was treated with 0.6M D2EHPA for recovery of manganese. This stage was then followed by a one-stage scrubbing of cobalt with O: A ratio of 20: 1.

Nowadays, there is an increasing demand for air-dry performance of fluorocarbon finished materials. Therefore, using different types of reactive, mono, bi, and multi-functional dyes were evaluated as a novel treatment to create correct surface interface to maintain fluorocarbon performance without ironing or tumble drying. The effects of pre-treatment on fluorocarbon finishing of cotton fabric, a cellulosic polymer, was investigated by measuring wash fastness as well as 3M water repellency test and samples hot pressing. The tensile strengths of the fabrics were compared. Also, effect of finishing on colour of the samples was examined. The results indicated that dyeing with proper reactive dye not only improve the fastness and repellency properties, but also the molecular re-orientation of fluorocarbon polymers for water repellency may reach to fulfilment level at ambient temperature. Furthermore, no negative effect on tensile properties and samples colour was observed.