International Journal of Engineering
Volume:29 Issue: 3, Mar 2016

In this work, polyvinylchloride (PVC) membrane prepared via casting solution technique and phase inversion method. N, N dimethylacetamide (DMAC) was used as primary solvent and Tetrahydrofuran (THF) was used as a co-solvent. The effects of parameters such as membrane thickness, evaporation time of casting film before immersion precipitation and addition of polyethylenglchol (PEG) on PVC membrane were studied in terms of deionized water flux (DIW), tensile strength, phase inversion time in non-solvent, water content, final wet thickness, permeability flux, salt rejection and antifouling properties. It consulted; DIW has an overhand relation by increasing of membrane thickness and prior casting film evaporation time. In addition there was a liner relation between membrane thickness and prior casting film evaporation time versus phase inversion time in non-solvent. The results revealed that by increasing prior casting film evaporation time, the tensile versus of strength force increase. In addition, water content percent was decreased by increasing of prior evaporation time. Besides, addition of PEG as a hydrophilic additive improved membrane performance by increasing of flux and less fouling during experiments.

In this research, Sauter-mean drop diameters and the flooding behavior have been investigated experimentally in a pilot scale Kühni extraction column. The experiments were carried out in the absence of mass transfer for two different standard chemical systems. In the experiments operating parameters including agitation speed, flow rate of both liquid phases and interfacial tension have been studied. The results showed that Sauter-mean diameter are strongly affected by agitation speed and interfacial tension but the effects of continuous phase and dispersed phase flow rates are negligible. An empirical correlation for prediction of mean drop size as a function of column geometry, operating conditions and physical properties of liquid systems is suggested with a mean deviation of 9.54 %. Flooding rate is also influenced mainly by rotor speed and interfacial tension. An empirical correlation for predicting flooding velocities is also proposed with a mean deviation of 11.54 %.

In this research thin film heterogeneous cation exchange membrane was prepared by interfacial polymerization of polyacrylic acid-co-iron nickel oxide nanoparticle son PVC based substrate. Spectra analysis confirmed graft polymerization conclusively. The SEM images showed that polymerized layer covers the membranes by simple gel network entanglement. Results exhibited that membrane water content was decreased by using of PAA/Fe2NiO4 nanoparticles interfacial polymerization. Membrane potential, transport number and permselectivity all were declined initially by PAA interfacial polymerization in NaCl ionic solution and then began to increase. The membrane transport number and permselectivity showed decreasing trend in bivalent (BaCl2) ionic solution. The sodium flux and permeability were improved sharply by PAA graft polymerization on membrane surface and then decreased slightly by using of Fe2NiO4 nanoparticles in surface modifier. Different trend was found for barium flux and permeability. Membrane areal electrical resistance was also decreased by introducing interfacial graft polymerization on membrane surface.

The demand for sustainable alternative construction materials to cement in modern technology cannot be underemphasized. This paper presents a non-fired green brick with an agriculture residue namely, rice husk. Although, high plasticity brown clay deposits are widely distributed in Malaysia and rice husk is a well known agriculture residue, research works on non-fired green brick with rice husk are relatively scarce. This research aims to investigate the strength development in non-fired bricks containing various amounts of rice husk. To achieve such aim, compression and flexural tests were conducted to evaluate compressive and flexural strengths of non-fired bricks. A series of brick specimens were cast with varying rice husk percentages. The test specimens were naturally sun dried. The effects of rice husk percentage (9-15%) and drying age (1, 7, 14, 21, and 28 days) on Atterberg limits; compressive strength; water absorption and flexural strength were investigated. The results indicate that, 12% rice husk is the optimum content to reach maximum 28-day compressive and flexural strengths of 10.4 MPa and 3.5 MPa respectively. The results further showed that rice husk higher than 12% leads lower strength than control bricks for all the ages. In summary, it has been observed that rice husk enables a rapid strength development, enhancing the compressive and flexural strengths of the bricks. The results developed in this research work can contribute a cost-effective design of non-fired green brick as a sustainable building material.

Video magnification is a computational procedure to reveal subtle variations during video frames that are invisible to the naked eye. A new spatio-temporal method which makes use of connectivity based mapping of the wavelet sub-bands is introduced here for exaggerating of small motions during video frames. In this method, firstly the wavelet transformed frames are mapped to connectivity space and then decomposed into different spatial frequency bands by applying Laplacian Pyramid to determine the pixels having more chance to be a part of a movement. Finally each candidate is partially magnified based on its time history. The performance of the proposed method is evaluated on real videos which contain several subtle motions. Parameters for performance evaluation are presented and obtained results are compared with one of state-of-the-art video magnification methods. Increased true positive rate in parallel with simultaneous decrease in false positive rate confirm the effectiveness of the proposed method in amplifying subtle motions.

This paper is focused on a novel design of stepped diaphragm for MEMS capacitive pressure sensor used in tire pressure monitoring system. The structure of sensor diaphragm plays a key role for determining the sensitivity of the sensor and the non-linearity of the output.First the structures of two capacitive pressure sensors with clamped square flatdiaphragms, with different thicknesses are investigatedand their sensitivity and non-linearityare compared together.Finally for increasing the sensitivity and linearity,anew capacitive pressure sensor with a stepped diaphragm is introduced. A numerical solution for determination of theaccurate sensitivity of the sensor is presented.The results show that the sensitivity of the sensor is increased from 0.063 fF/KPa with flat diaphragm to 0.107 fF/KPa with stepped diaphragm and also the non-linearity is decreased from 2.37% to 1.857%. In this design, the sensor sensitivity and output linearity are increased simultaneously.

Diffusion tensor imaging (DTI) MRI is a noninvasive imaging method of the cerebral tissues whose fibers directions are not evaluated correctly in the regions of the crossing fibers. For the same reason the high angular resolution diffusion images (HARDI) are used for estimation of the fiber direction in each voxel. One of the main methods to specify the direction of fibers is usage of the spherical deconvolution. The spherical deconvolution is a method which is very sensitive to noise and creates negative values in the orientation distribution function (ODF) of the fiber. To solve this problem, methods such as Laplace-Beltrami regularized spherical deconvolution (LB-SD), the gradient based spherical deconvolution(GB-SD) and the constrained spherical deconvolution (CSD) are used. In this paper the method for SD based on Wiener filter (WB-SD) is presented. Regarding the results, the direction of the crossing fibers is specified correctly. The proposed algorithm has specified the direction of the fibers as zero degree with 4.9 standard deviation and 89.9 degree with 3.6 standard deviation against two crossing fibers with 90 degree angle.

In this article a new method is introduced for distinguishing roots and background based on their digital curvelet transform in minirhizotron images. In the proposed method, the nonlinear mapping is applied on sub-band curvelet components followed by boundary detection using energy optimization concept. The curvelet transform has the excellent capability in detecting roots with different orientations and contrasts, thanks to its better sparse representation and more directionality feature than existing approaches. Furthermore adapting the parameters of the mapping function due to curvelet coefficients is very beneficial for magnifying weak ridges as well as better compatibility with different minirhizotron images. Performance of the proposed method is evaluated on several minirhizotron images in two different scenarios. In the first scenario, images contain several roots while the second scenario belongs to no-root images, which increases the chance of false detections. The obtained results show the greater ability of the proposed method in characterizing roots in minirhizotron images compared to some alternative algorithms. Furthermore it is shown that better characterization of roots by proposed algorithm does not lead to extract more false objects compared to the results of the other examined algorithms.

The problem of Dynamic Job Shop (DJS) scheduling is one of the most complex problems of machine scheduling. This problem is one of NP-Hard problems for solving which numerous heuristic and metaheuristic methods have so far been presented. Genetic Algorithms (GA) are one of these methods which are successfully applied to these problems. In these approaches, of course, better quality of solutions, avoiding premature convergence, and robustness of solutions is still among the challenging arguments and in the researchers’ center of attention. The investigations in real manufacturing environments indicate that many of these systems have Bottleneck Recourses (BR). According to the concepts of the Theory of Constraint (TOC), the output of manufacturing systems is limited based on BR capacity. Hence, for improving system performance, one must find and investigate the improvement of BR effects in different levels of decision-making. Moreover, the capacity of these resources should be improved to the maximum possible limit. In this study, for detecting and using BR in shop floor decisions (e.g. scheduling), a new detection method of bottleneck for DJS problems known as bottleneck detection method based on Taguchi Approach (TA-DJS) has been developed. On the other hand, the adapting of GA operators in amount and range of coverage can operate as an efficient approach in improving its operation and effectiveness. In this way, the adapting for operators prevents its premature convergence and the adapting in the range of coverage causes maximum use of the problem’s important resources and better performance of the algorithm in each step of its run. In the proposed GA (GAIA), initially the adapting in the amount of algorithm’s operators based on the solutions’ tangent rate for premature convergence is done, then the adapting in the range of coverage of operators’ algorithm, in first step, happens by operators convergence on BR (which was detected initially) and, in the next step, occurs by operators convergence on the elite solutions so that the search process focuses on more probable ranges than the whole range of solution. Comparing the problem results in the static state with the results of other available methods in the literature indicated high efficiency of the proposed method.

Currently, the research of emergency supplies distribution and decision models mostly focus on deterministic models and exact algorithm. A few of studies have been done on the multi-level distribution network and matheuristic algorithm. In this paper, random processes theory is adopted to establish emergency supplies distribution and decision model for multi-level network. By analyzing the characteristics of the model, a modified discrete particle swarm optimization matheuristic algorithm (MBPSO) is proposed to solve the problem. In MBPSO, appropriate degradation mechanism and parallel global search structure is designed. Through a instance, MBPSO has capability of global optimuml search and fast convergence property for hybrid integer programming model with multi-constrained and weighted single objective.

This paper aims to find the efficient state of hybrid electric vehicle (HEV) by simultaneous optimization of the control strategy and the power train. The power transmission employed in this vehicle is a power-split continuously variable transmission (CVT) which uses several fixed ratio mechanisms. After describing this transmission, the rules of electric assist control strategy are introduced. A modification on this strategy is proposed to decrease the start/stop frequency of the engine and electric motor. Afterwards, an optimization on the HEV’s power train size, power-split CVT and the control strategy is accomplished with the aim of minimizing the vehicle fuel consumption and emissions. The optimization results are some Pareto-optimal points which are tradeoff solutions between fuel consumption and emissions. Finally, in order to intuitively demonstrate the optimality of the optimization results, the Pareto points for the case of considering two objectives are shown.

To overcome the space limit of orifice-type and capillary restrictors in hybrid bearings, a kind of atypical long orifice-type restrictor is proposed and its experimental model is established. Through the analysis of the structure and flow rate of orifice-type restrictor and capillary restrictor, a long orifice-type restrictor and a feasible experimental modeling method are presented by use of orifice plate instead of the whole bearing. The flow rate of water film restrictors are tested under the aspect ratio of 4-10 and the pressure difference of 1.5-5.5MPa and the experimental model of long orifice-type restrictor is established. The result shows that the restrictor of atypical structures needs to be modeled by experiment. The flow discipline of atypical restrictor is approximate to typical orifice-type restrictor and the throttling model is a nearly turbulent model.

In this paper, the consequences of filled volume on the transient lateral dynamic and stabilities boundaries displacement of an articulated vehicle carrying liquid is investigated. First, a sixteen-degrees-of-freedom nonlinear dynamic model of an articulated vehicle is developed then, using TruckSim software the model is validated. Next, the dynamic interaction of the fluid cargo with the vehicle, by integrating a quasi-dynamic slosh model with a tractor semitrailer model is investigated. In this study, the most important dynamic reposes are considered which include yaw rate, roll angle and lateral acceleration for both the tractor and semitrailer as well as liquid center of mass lateral movement. Also, to investigate the rollover stability of the vehicle, lateral load transfer ratio is considered as an important factor. The dynamic system performance for three different filled volumes is exhibited in j-turn and lane change standard maneuvers. The simulation results revealed that by increasing the liquid volume the rollover probability rises due to the increase in roll angle and lateral load transfer, especially in lane change maneuver.

In the present work, an inverse analysis of combined radiation and laminar forced convection heat transfer in a two-dimensional channel with variable cross sections is performed. The conjugate gradient method is used to find the temperature distribution over the heater surface to satisfy the prescribed temperature and heat flux distributions over the design surface. The fluid is considered to be a gray participating medium with absorption, emission and isotropic scattering. The discrete ordinate method is used to solve the radiative transfer equation. The effect of radiation-conduction parameter is studied on the amount of heat transfer from the heater surface.

The axial force measurement plays important role in tool designing and identification of its restrictions. Also, it is vital in design of machine mechanism and optimization of welding process parameters. In this study, a friction stir welded butt join on AA7075-T651 aluminum alloy plate is investigated. With change of some parameters, factors including axial force, mechanical properties, microhardness and weld morphology, are studied. For measuring axial force, load cell was utilized and a servohydraulic machine was applied to evaluate the mechanical properties. The results show that by increasing the welding speed and in the same rotational rate, the axial force and microhardness increase but the weld appearance quality decreases. However, by increasing the rotational rate in the same welding speed, there is not any certain relationship among the axial force, hardness and weld morphology. Also, by changing the tool tilt angle from zero to 2.5 degrees, the more weld morphology achieves. The results show that the change in welding speed and rotational rate have great effects in optimizing the welding friction stir process.

In the present study, small scale effect on critical buckling loads of triangular nano- composite plates under uniform in-plane compression is studied. Since at nano-scale the structure of the plate is discrete, the size dependent nonlocal elasticity theory is employed to develop an equivalent continuum plate model for this nanostructure incorporating the changes in its mechanical behavior. The two-parameter, Winkler-Pasternak, elastic medium is used for precisely modelling the behavior of matrix surrounding the nano-plate. The governing stability equations are then derived using the classical plate theory and the principle of virtual work for a perfect uniform triangular nano-plate composite. The well-known numerical Galerkin method in conjunction with the areal coordinates system is used as the basis for the solution. The solution procedure views the entire nano-composite plate as a single super-continuum element. Effects of nonlocal parameter, length, aspect ratio, mode number, anisotropy, edge supports and elastic medium on the buckling loads are rigorously investigated. All of these parameters are seen to have significant effect on the stability of nano-composite plate. It is shown that the results depend obviously on the non-locality of buckled nano-composite plate, especially at very small dimensions, small aspect ratios, higher mode numbers, higher anisotropy degree, stiffer edge supports and softer elastic mediums. Also, it is seen that the classical continuum mechanics overestimates the buckling results which can lead to deficient design and analysis of these widely used nanostructures.

This paper examines the generation and propagation of a Third order solitary water wave along the channel. First the Incompressible Smoothed Particle Hydrodynamics (ISPH) numerical method is described and the boundary condition handling method is presented. The numerical model is then used to simulate solitary wave propagation along the fixed depth channel. The numerical results are compared with analytical data in terms of free surface displacements, fluid particle velocity, phase speed, flow field counters and some other wave parameters. In general, the numerical model gives satisfactory results for the wave kinematics.