Effects of Compactor Types on Aggregate Orientation of Asphalt Mixtures
Noor Halizah
Abdullah
Civil Engineering, University Sains Malaysia
author
Woei Chew
Von
Civil Engineering, Lee & Lee Consultant PTE LTD
author
text
article
2013
eng
More than 90% of Malaysian roads are constructed using asphaltic concrete. However, previous investigations of asphaltic concrete have mainly concentrated on the macroscopic properties of the composite materials based on the assumption that the mixtures are homogeneous and isotropic. This paper applies a digital image processing technique to compare the orientations of coarse aggregate particles in asphaltic concrete compacted using Marshall, Servopac and Presbox compactors. The results illustrate that the Servopac compactor produces specimens where the aggregates are more randomlyoriented. However, the Presbox compactor produces specimens that are most randomly oriented at 100% geometrically cubical shape (GCS) aggregate content. Further analysis shows that compaction method has significant effect on aggregate orientation while GCS aggregate content shows otherwise.
International Journal of Engineering
Materials and Energy Research Center
1025-2495
26
v.
7
no.
2013
677
684
https://www.ije.ir/article_72138_1c61bde4cb3787804d7b941f1d69c200.pdf
Numerical Study of Progressive Collapse in Framed Structures: A New Approach for Dynamic Column Removal (TECHNICAL NOTE)
Foad
Kiakojouri
Structural Engineering, Urmia University
author
text
article
2013
eng
Progressive collapse is a situation where local failure of a primary structural component leads to the collapse of adjoining members which, in turn, leads to additional collapse. Hence, the total damage is disproportionate to the original cause. The most common local failure in framed structure is assumed to be column failure. In this paper, a new approach for dynamic column removal in framed structures was proposed. Using this approach, the structural response of the 5-story steel building under the sudden loss of columns for different scenarios of column removal was assessed. Both material and geometric nonlinearities are taken into account in the analysis. The modeling techniques were described in details. Special emphasis is focused on the evolution of vertical displacements of column removal point. According to results progressive collapse potential are strongly dependent on location of column loss. It could be concluded that the proposed approach offers the advantages of computational simplicity and practicality for dynamic column removal of framed structures.
International Journal of Engineering
Materials and Energy Research Center
1025-2495
26
v.
7
no.
2013
685
692
https://www.ije.ir/article_72139_ddc3789512e471e6c2e3188e7045c1c2.pdf
Optimum Location of Outrigger-belt Truss in Tall Buildings Based on Maximization of the Belt Truss Strain Energy
Mohammad Reza
Jahanshahi
Civil Engineering Group, Shahid Bahonar University of Kerman
author
Reza
Rahgozar
Civil Engineering, Shahid Bahonar University of Kerman
author
text
article
2013
eng
In this paper, based on maximizing the outrigger-belt truss system’s strain energy, a methodology for determining the optimum location of an outrigger-belt truss system is presented. Tall building structures with combined systems of framed tube, shear core and outrigger-belt truss system’s are modeled using continuum approach. In this approach, the framed tube system is modeled as a cantilevered beam with box cross section. The effect of outrigger-belt truss and shear core system on framed tube’s response under lateral loading is modeled by a rotational spring at the outrigger-belt truss location. Optimum location of this spring is obtained when energy absorbed by the spring is maximized. For this purpose, first derivative of the energy equation with respect to spring location as measured from base of the structure, is set to zero. Optimum location for outrigger-belt truss system is calculated for three types of lateral loadings, i.e. uniformly and triangularly distributed loads along structure’s height, and concentrated load at top of the structure. Accuracy of the proposed method is verified through numerical examples. The results show that the proposed method is reasonably accurate.
International Journal of Engineering
Materials and Energy Research Center
1025-2495
26
v.
7
no.
2013
693
700
https://www.ije.ir/article_72140_b20e2cd563591a14e5864ea70ed946b3.pdf
Microstructure and Grain Refining Performance of a New Al-Ti-C Master Alloy (RESEARCH NOTE)
Tohid
Naseri
Ceramic, MERC
author
Mahboubeh
Momeni
Ceramic, Material and Energy Research Center
author
Mohammad Reza
Rahimipour
Ceramic, Merc
author
text
article
2013
eng
Control of microstructure parameters that affecting the Al-Ti-C master alloys grain refining efficiency is leading to improve the aluminum grain refinement. This study was an attempt to produce Al-Ti-C master alloys that provide these controlling factors with relying on the solute effect theory. The produced master alloys were examined by using scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), and X-ray diffraction (XRD); moreover, the effect of them on pure aluminum was investigated. Produced Al-6Ti-1C master alloy contained Ti and TiC particles within the aluminum matrix and Al-4Ti-1C contained TiC particles within the aluminum matrix. As the result, produced Al-6Ti-1C master alloy is a more efficient grain refiner for pure aluminum compared with the Al-4Ti-1C one that verified the effect of Ti particles for grain refinement. The results indicated Al-6Ti-1C master alloy had maximum grain refining performance when holding time was 2 minutes, temperature was 983 K, and master alloy addition level was 1% wt. Finally, a new Al-Ti-C master alloy with excellent refinement was prepared successfully.
International Journal of Engineering
Materials and Energy Research Center
1025-2495
26
v.
7
no.
2013
701
706
https://www.ije.ir/article_72141_1ddd3eae026d95ce782089acfdfc1aa0.pdf
Titanium Oxide (TiO2) Coatings on NiTi Shape Memory Substrate Using Electrophoretic Deposition Process
Hossein
Maleki-Ghaleh
Research Center for Advanced Materials and Mineral, Sahand University of Technology
author
Jafar
Khalil-Allafi
Research Center for Advanced Materials and Mineral, Sahand University of Technology
author
Vida
Khalili
Department of material, Sahand University of Technology
author
text
article
2013
eng
The aim of the present research is to convert bioinert surface of NiTi to bioactive and biocompatible surface. In order to develop a bioactive and corrosion resistant film on NiTi, electrophoretic deposition process was done and TiO2 particles were deposited on the NiTi surface. Suspensions including TiO2 particles were prepared using a mixture of acetone and n-butanol (0%, 30%, 60%, 80% and 100% acetone) without using any dispersant. Sedimentation test was used to characterize the suspensions. SEM investigations on surface morphology of coatings shows depositing within 0% acetone cause to crack-free and dense coating with relatively coarse grains and high corrosion resistance.
International Journal of Engineering
Materials and Energy Research Center
1025-2495
26
v.
7
no.
2013
707
712
https://www.ije.ir/article_72142_d2822b0b3dfa84ac74e1334d15bfd0e3.pdf
Production of Cu-Cr-Zr Alloy Using Electro Slag Remelting Technique (RESEARCH NOTE)
Hadi
Ghaffari
R & D, MAPNA GROUP
author
Mozhgan
Kermajani
R & D, MAPNA GROUP
author
Kazem
Hanaii
Metallurgy engineering, University of Tehran
author
text
article
2013
eng
This study focused on the effect of electro slag remelting process (ESR) on microstructure and composition of an as-cast alloy of Cu-Cr-Zr. These observations revealed that applying ESR process results in a more uniform distribution of alloying elements, however a slight aggregation of large precipitates and inclusions existed in as-cast ingot was found. Additionally, impurities like P, S and Mg which has a significant effect on electrical properties have been eliminated after ESR process. Moreover, further optimization of alloy composition which in turn will affect its mechanical and electrical properties was obtained through using ESR technique successfully.
International Journal of Engineering
Materials and Energy Research Center
1025-2495
26
v.
7
no.
2013
713
720
https://www.ije.ir/article_72143_9a93bc9866cbaf18988c107430ac96fc.pdf
Investigation of the Effect of Atmosphere on the Pores of Sintered Astaloy CrM Steel
text
article
2013
eng
Abstract Image analysis is used to study the effect of sintering atmosphere and sintering times on the pores morphology of Astaloy CrM. The pores morphology was described by means of some parameters, Circular Diameter (DC)- which shows the diameter of equivalent circle for comparing the pore size, FElongation and FShape- which have different geometrical meanings. The results have been interpreted with reference to an elliptical geometry which represents the theoretical shape to which pores tends. Effect of different sintering atmospheres (N2, Cracked Ammonia (NH3), Ar, Vacuum and air) at 1200ºC was investigated. The results showed 20% decrease of Maximum DC in Vacuum and Cracked Ammonia in comparison with other atmospheres. The pore size measurement by image analyses confirmed the variation of density measured by Archimedes method. Dc was affected by Atmosphere more than Fshape and FElongation. Furthermore, Fshape was more sensitive than Felongation to different sintering atmospheres. Mechanical properties of specimens have a significant relation with percentage of pores (porosity) and morphology. Vacuum atmosphere led to more spherical and finer pores. Sintering atmosphere has significant effect on pores size and pore distribution in comparison with other morphological parameters in Astaloy CrM. Differences in FShape and FElongation factors is more observable in large pores (over 75µm2 area) in comparison with smaller ones. Fshape seems to be more suitable than Felongation for evaluating the effect of sintering variables on the evolution of pores morphology.
International Journal of Engineering
Materials and Energy Research Center
1025-2495
26
v.
7
no.
2013
721
728
https://www.ije.ir/article_72144_65a04ca98401d28a108cca03badc2bbe.pdf
Stability and Numerical Analysis of Malaria- mTB- HIV/AIDS Co-infection (TECHNICAL NOTE)
G. C.
Sharma
Mathematics, I.B.S, AGRA
author
Priyanka
Agarwal
, I.I.I. ROORKEE
author
Atar
Singh
Mathematics, Agra College, Agra, India-282002
author
text
article
2013
eng
In this paper, we develop a mathematical model to examine the transmission dynamics of curable malaria, curable mTB and non-curable HIV/AIDS and their co-infection. The size of population has been taken as varying due to the emigration of susceptible population. The total population is divided into five subclasses as susceptible, malaria infected, mTB infected, HIV infection and AIDS by assuming co-infection among them. The model has two basic parts, qualitative and numerical. In qualitative part, we analyze the transmission dynamics of this co-infection by using equilibrium and stability analysis. In numerical part, the computational simulation is used to transmission flow of disease among various classes. The sensitive analysis is also performed.
International Journal of Engineering
Materials and Energy Research Center
1025-2495
26
v.
7
no.
2013
729
742
https://www.ije.ir/article_72145_fa70497903f363c6ac93a2c802066a05.pdf
Availability of k-out-of-n: F Secondary Subsystem with General Repair Time Distribution
ASHISH
MISHRA
MATHEMATICS, INSTITUTE IF BASIC SCIENCE
author
Priyanka
Agarwal
, I.I.I. ROORKEE
author
text
article
2013
eng
In this paper we study the steady state availability of main k-out-of-n: F and secondary subsystems having general repair time distribution. When more than k units of main subsystem fail, then the main subsystem shuts off the secondary subsystem. The life time distributions of the main units and that of secondary subsystem are exponentially distributed. A repair facility having single repairman is facilitated to restore the failed unit. Failure of the main unit shuts off the operation of secondary subsystem, but not vice versa. Failure of the main unit or the secondary subsystem initiates the system shut down. The steady state availability is obtained by solving the linear ordinary differential equations governing the model by using supplementary variable technique.
International Journal of Engineering
Materials and Energy Research Center
1025-2495
26
v.
7
no.
2013
743
752
https://www.ije.ir/article_72146_f47d57e9bc7e9375ec6b8e1fcb1875ab.pdf
Thermal Convection in a (Kuvshiniski-type) Viscoelastic Rotating Fluid in the Presence of Magnetic Field through Porous Medium (TECHNICAL NOTE)
Vivek
Kumar
Mathematics, S. G. R. R. ( P.G.) College, Dehradun
author
text
article
2013
eng
The effect of magnetic field on an incompressible (Kuvshiniski-Type) viscoelastic rotating fluid heated from below in porous medium is considered. For the case of stationary convection, magnetic field and medium permeability have both stabilizing and destabilizing effect on the thermal convection under some conditions whereas rotation has a stabilizing effect on the thermal convection. In the absence of rotation, medium permeability has a destabilizing effect while magnetic field has a stabilizing effect on the thermal convection in a Kuvshiniski viscoelastic rotation fluid. It is also found that presence of magnetic field and rotation introduced oscillatory modes in the system, whereas in their absence Principle of Exchange of Stabilities is satisfied in the system. Graphs also have been plotted by giving some numerical values to the parameters.
International Journal of Engineering
Materials and Energy Research Center
1025-2495
26
v.
7
no.
2013
753
760
https://www.ije.ir/article_72147_da8a221a17d43ad779cacbf0faf6bbe8.pdf
Flow Re-Stabilizing Observation via Air Injection during the Rotating Stall through a Single-stage Axial Compressor by a 2-D Finite-volume Approach
Nima
Amanifard
Mechanical Engineering, University of Guilan
author
Pedram
Mojtabavi
Mechanical Eng., University of Guilan
author
Hamed
Mohadess Deylami
Mechanical Engineering, University of Guilan
author
text
article
2013
eng
The air-injection as an active flow stabilizing techniques, were numerically examined in current work, during the aerodynamic behavior and the characteristics of an axial compressor. At first, in design condition the characteristic curve was numerically captured for a specified test compressor. The computed results showed good agreements with those obtained from the experiments, to validate the finite-volume solver which was developed based on Van Leer’s flux splitting algorithm in conjunction with TVD limiters and the κ-e turbulence model. At the second step, to examine the performance of the air injection technique unstable condition, the operating points were set for the unstable condition upon the operating map, and the expected unstable flow patterns were captured. At the final step, the numerical simulation was completed with the air injection, and surprisingly, the unstable flow patterns became highly re-stabilized, and consequently a significant recovery of the performance was augmented. The study could successfully demonstrate the capability of the numerical studies for simulating the active flow controls specifically the inlet air-injection technique by using a 2-D finite volume approach
International Journal of Engineering
Materials and Energy Research Center
1025-2495
26
v.
7
no.
2013
761
770
https://www.ije.ir/article_72148_d1bd252434dd5b017679c742940713dc.pdf
Numerical Investigation of Heat Transfer and Pressure Drop in a Corrugated Channel
Ramin
kouhikamali
faculty of engineering, university of guilan
author
Mehdi
Sanaei
Mechanical Engineering, University of Guilan
author
Nima
Amanifard
Mechanical Engineering, University of Guilan
author
Hamed
Mohadess Deylami
Mechanical Engineering, University of Guilan
author
text
article
2013
eng
The influence of variation in rib-height to channel-height ratio (e/H) on the heat transfer and pressure drop characteristics inside a channel with corrugated upper and lower plates was investigated numerically in the present study. The governing equations were solved by using finite volume approximations for a wide range of (0.06 < e/H < 0.26) and Reynolds numbers (5400 < Re < 23000), with a more concern on using the more adequate turbulent model. The computed results demonstrate the noticeable effects of this character on the heat transfer performance as well as the pressure drop to achieve the most effective and optimal corrugation design. In addition, RNG turbulent model has better agreement with the experimental data.
International Journal of Engineering
Materials and Energy Research Center
1025-2495
26
v.
7
no.
2013
771
780
https://www.ije.ir/article_72149_b0c7f1289da1b15f3ad7263d87d4b2ac.pdf
Lattice Boltzmann Simulation of Deformation and Breakup of a Droplet under Gravity Force Using Interparticle Potential Model
S. E.
Mousavi Tilehboni
Mechanical Engineering, Babol University of TechnologyBabol Noshirvani Uni
author
text
article
2013
eng
Abstract In this paper interparticle potential model of the lattice Boltzmann method (LBM) is used to simulate deformation and breakup of a falling droplet under gravity force. First this model is applied to ensure that the surface tension effect is properly implemented in this model. Two tests have been considered. First, it has been checked an initial square drop in a 2D domain can freely deform to a circular drop and secondly the coalescence of two static drops that merge to become a single circular drop is simulated. In order to further verify the model, Laplace law for static drops is performed. In the next step, wall effects on the droplet shape and its average velocity have been studied. it is seen that average velocity of droplet at different times is independent of wall effects when the ratio of the width of channel to droplet diameter (W/D) is more than 6. In the final section of the paper deformation and breakup of a falling droplet for some range of Eotvos and Ohnesorge numbers are investigated. It is seen that at very low Eotvos numbers, where the surface tension force is dominant, the droplet deforms slowly and reaches a steady state without breakup. At higher Eotvos numbers gravitational force overcome the surface tension force and the droplet deforms more. For breakup modes at small Ohnesorge number, if Eotvos number be increased to the middle value, the droplet deforms more than from state of low Eotvos number value and eventually forms a backward-facing bag. Finally for high Eotvos numbers, fragments of droplet are sheared from the edges and the shear breakup mechanism is seen. On the other hand the stabilizing effect of the Ohnesorge number, (the ratio of viscous stresses and surface tension) , is shown. At higher Ohnesorge number, the simulations show that the main effect of increasing Ohnesorge number is to move the boundary between the different breakup modes to higher Eotvos number.
International Journal of Engineering
Materials and Energy Research Center
1025-2495
26
v.
7
no.
2013
781
794
https://www.ije.ir/article_72150_2c7bc8bab2d24860bd98e1f6112ad818.pdf
Element Free Galerkin Method for Static Analysis of Thin Micro/Nanoscale Plates Based on the Nonlocal Plate Theory
Abusaleh
Naderi
Mechainical Engineering, Graduate University of Advanced Technology
author
Gholamhosein
Baradaran
Mechanical Engineering , Shahid Bahonar University of Kerman
author
text
article
2013
eng
In this article, element free Galerkin method is used for static analysis of thin micro/nanoscale plates based on the nonlocal plate theory. The problem is solved for the plates with arbitrary boundary conditions. Since shape functions of the element free Galerkin method do not satisfy the Kronecker’s delta property, the penalty method is used to impose the essential boundary conditions. Discrete form of the equilibrium equation is solved to obtain the plate deflection. Numerical results show that the number of nodes scattered in the plate domain, support domain radius, Gauss quadrature points affect the final results. So, before presentation of the results the element free Galerkin method is calibrated with the exact results. Finally, bending problem of nano graphene sheets as orthotropic thin nonlocal plates is solved for different boundary conditions.
International Journal of Engineering
Materials and Energy Research Center
1025-2495
26
v.
7
no.
2013
795
806
https://www.ije.ir/article_72151_bdcc7a4aa334750323d1f48d722748e6.pdf