ORIGINAL_ARTICLE
Effects of Pozzolanic Admixture (Waste Bricks) on Mechanical Response of Mortar
This work presents an experimental study realized at the materials laboratory of the University of M’sila. It consists to vary the percentage of the pozzolanic admixture (waste bricks) in cement by the substitution method (partial replacement of the clinker by the calcined clay). The characteristics of cement at anhydrous state and the hydrated state (chemical composition, specific weight and fineness, consistency of the cement paste, setting times and shrinkage) were studied thus that the mechanical behavior (flexural and compressive strengths) for the mortar was determined. According to the experimental results obtained, it comes that the quantity of pozzolanic admixture (calcined clay) and the chemical composition of cement manufactured are the principal parameters that influence on the variation of the mechanical strengths (flexural and compressive) of the mortars tested.
https://www.ije.ir/article_71681_d41d8cd98f00b204e9800998ecf8427e.pdf
2008-04-01
1
8
Pozzolanic Admixture
Waste Bricks
cement
Mortar
Mechanical Strength
M.
Chikouche Hamina
hasnomail@ije.ir
1
Civil Engineering, M’sila University
AUTHOR
A.
Naceri
abdelghani_naceri@yahoo.fr
2
Civil Engineering, M'sila University
AUTHOR
ORIGINAL_ARTICLE
Fixing of Cycle Slips in Dual-Frequency GPS Phase Observables using Discrete Wavelet Transforms
The occurrence of cycle slips is a major limiting factor for achievement of sub-decimeter accuracy in positioning with GPS (Global Positioning System). In the past, several authors introduced a method based on different combinations of GPS data together with Kalman filter to solve the problem of the cycle slips. In this paper the same philosophy is used but with discrete wavelet transforms. For experiments we simulated artificial cycle slips in real data. Studies show that the selection of a proper wavelet basis functional basis for wavelet is a very important problem in wavelet transforms. Wavelet transforms accurately detects the place of cycle slips, especially in low noise test quantities.
https://www.ije.ir/article_71682_de8ea1357a2674c6d302e93172faa394.pdf
2008-04-01
9
26
GPS
Cycle Slip
Geodetic Positioning
Phase Observations
Discrete Wavelet transform
B.
Voosoghi
1
Civil Engineering, Khaje Nasir Toosi University of Technology
AUTHOR
A.
Rastbood
hasnomail@ije.ir
2
Civil Engineering, Khaje Nasir Toosi University of Technology
AUTHOR
ORIGINAL_ARTICLE
A Solution of Riccati Nonlinear Differential Equation using Enhanced Homotopy Perturbation Method (EHPM)
Homotopy Perturbation Method is an effective method to find a solution of a nonlinear differential equation, subjected to a set of boundary condition. In this method a nonlinear and complex differential equation is transformed to series of linear and nonlinear and almost simpler differential equations. These set of equations are then solved secularly. Finally a linear combination of the solutions completes the answer if the convergence is maintained. HPM based solution incorporates some reasonable assumptions. These are inspired from the boundary condition and a separation mechanism. In this paper, the need for stability verification is shown trough some examples. The novel idea is to keep the inherent stability of nonlinear dynamic in whole term, even if the selected linear part is not stable. Consequently, HPM is enhanced by a preliminary assumption. The proposed method is applied to Riccati equation as well as some other problems. The simulation result verifies the significance of the method whilst numerical and the exact solutions confirm the achievement.
https://www.ije.ir/article_71684_d41d8cd98f00b204e9800998ecf8427e.pdf
2008-04-01
27
38
Homotopy Perturbation Method
Secular Terms
Nonlinear Dynamic
Nonlinear Differential Equation
Enhanced HPM (EHPM)
Optimal control
H.
Soltani
hamidsoltani408@gmail.com
1
Electerical Engineering, National Institute of Technology
AUTHOR
S. H.
Hosseinnia
2
Electerical Engineering, University of Mazandaran
AUTHOR
Abolfazl
Ranjbar
a.ranjbar@nit.ac.ir
3
Control, Babol Noshirvani university of Technology
AUTHOR
J.
Ghasemi
jghasemi@stu.nit.ac.ir
4
Electerical Engineering, University of Mazandaran
AUTHOR
ORIGINAL_ARTICLE
Statistical Background Modeling Based on Velocity and Orientation of Moving Objects
Background modeling is an important step in moving object detection and tracking. In this paper, we propose a new statistical approach in which, a sequence of frames are selected according to velocity and direction of some moving objects and then an initial background is modeled, based on the detection of gray pixel's value changes. To have used this sequence of frames, no estimator or distribution is required. In this work, smoothly changing pixels are modeled by averaging and other statistical calculations are done for more varying pixels. The proposed algorithm works well, even if the moving objects are present in all frames. We have evaluated this novel method successfully on highly textured scenes, with challenging phenomena such as dynamic background, area of high foreground traffic and moving objects with different speeds and sizes.
https://www.ije.ir/article_71686_d41d8cd98f00b204e9800998ecf8427e.pdf
2008-04-01
39
54
Background Modeling
Orientation
Velocity
Modified Set of Frames
Gholamreza
Ardeshir
g.ardeshir@nit.ac.ir
1
Elect & Computer Engineering, Babol Nooshirvani University of Technology
AUTHOR
S.
Sharifzadeh
sarasharifzade@yahoo.com
2
Electerical Engineering, University of Mazandaran
AUTHOR
H.
MiarNaimi
h_miare@nit.ac.ir
3
Computer & Electrical Engineering, Babol Noshiravani University of Technology
AUTHOR
ORIGINAL_ARTICLE
Causes of Catastrophic Failure of High Mn Steel Utilized as Crusher Overlaying Shields (TECHNICAL NOTE)
The secondary cone crusher's shields at Sarcheshmeh Copper Complex of Iran are made of Hadfield steel with a nominal composition of Fe-1.3 % C-12 % Mn. They have a cut-off in the shape of a cone with an upper end diameter of 80cm and an approximate lower end diameter of 200 cm whose main problem is an unexpected early failure under normal working condition. In this paper, the results of metallographic and fractographic studies carried out on a failed shield at various depths and analytical examinations of the fractured regions are presented. It is revealed that crack propagation starts from the pre-existing microcracks in the internal regions of the shield and results in a catastrophic failure. Analytical examinations indicated other problems associated with the chemical composition of the shield. An Mn/C ratio of < 10 and high sulfur and phosphorus concentrations in the inclusions as compared to that of bulk are typical examples. The latter together with the carbide precipitation in the grain boundaries can be regarded as the pre-existing crack path in these high energy regions of the shield substructure.
https://www.ije.ir/article_71688_d41d8cd98f00b204e9800998ecf8427e.pdf
2008-04-01
55
64
Cone Crusher
Hadfield Steels
Chemical composition
Casting
Heat treatment
Failure
Fractography
S. R.
Allahkaram
1
Materials Engineering, Sharif University of Technology
AUTHOR
ORIGINAL_ARTICLE
Two-Stage Chemical Deposition of Oxide Films
Two-stage chemical deposition (TSCD) technique is used to produce ZnO, Mn2O3 and NiO films on soda-lime glass (SL-G) from an aqueous solution of zinc, manganese and nickel complex, respectively. The TSCD method enables the deposition of metal oxide thin films with a thickness which can be controlled during the preparation procedure. The ZnO, Mn2O3 and NiO thin films were polycrystalline films which were adherent well to the substrates. The SEM micrographs clearly indicate that the zinc oxide layer is composed of oval shaped crystallites preferably orientated perpendicular to the surface of the substrate. The Mn2O3 and NiO layers were closely packed on the substrate. These particles seem to grow from the surface of the substrate.
https://www.ije.ir/article_71690_d41d8cd98f00b204e9800998ecf8427e.pdf
2008-04-01
65
70
Zinc oxide
Manganese oxide
Nickel Oxide
Soda
lime
Oval
Shaped Particles
S.K.
Sadrnezhaad
1
Materials Science and Engineering, Sharif University of Technology
AUTHOR
M.R.
Vaezi
vaezi9016@yahoo.com
2
Nanotechnology and Advanced Materials Department, Material and Energy Research Center(MERC)
AUTHOR
ORIGINAL_ARTICLE
Modeling and Control of Gas Turbine Combustor with Dynamic and Adaptive Neural Networks (TECHNICAL NOTE)
https://www.ije.ir/article_71692_d41d8cd98f00b204e9800998ecf8427e.pdf
2008-04-01
71
84
Control
Modeling
Gas Turbine Combustor
Neural Network
Adaptive Control System
M.
Lahroodi
1
Mechanical Engineering, Sharif University of Technology
AUTHOR
A.A.
Mozafari
mozafari@sharif.edu
2
Mechanical Engineering, Sharif University of Technology
AUTHOR
ORIGINAL_ARTICLE
Analysis of Natural Frequencies for a Laminated Composite Plate with Piezoelectric Patches using the First and Second Eigenvalue Derivatives
In this paper, the first and second order approximations of Taylor expansion are used for calculating the change of each natural frequency by modifying an arbitrary parameter of a system with a known amount and based on this approximation, the inverse eigenvalue problem is transformed to a solvable algebraic equation. The finite element formulation, based on the classical laminated plate theory (CLPT) is presented for laminated composite plates with piezoelectric patches. Using the proposed FE model, sensitivity analysis is carried out, to find the effects of the changes made in the design parameters such as the piezoelectric patch thickness and the fiber angles in each layer on the natural frequencies of the structure. The inverse eigenvalue problem is solved in order to find the thickness of piezoelectric patches and stacking sequence for relocating the natural frequencies.
https://www.ije.ir/article_71694_cdca740f382ce49aaa52b112769204ca.pdf
2008-04-01
85
96
Composite
Piezoelectric
Natural frequency
Sensitivity analysis
Inverse Eigenvalue Problem
F.
Bakhtiari-Nejad
1
AUTHOR
F.
Aryana
f_aryana@mail.uk.ac.ir
2
Mechanical Engineering, Shahid Bahonar University of Kerman
AUTHOR
M.
Naseralavi
naseralavi31@yahoo.com
3
Mechanical Engineering, Shahid Bahonar University of Kerman
AUTHOR
R.
Mirzaeifar
mirzaeifar@aut.ac.ir
4
Mechanical Engineering, Amirkabir University of Technology
AUTHOR
ORIGINAL_ARTICLE
Effect of Ignition Timing, Equivalence Ratio, and Compression Ratio on the Performance and Emission Characteristics of a Variable Compression Ratio Si Engine using Ethanol-Unleaded Gasoline Blends
This paper investigates the effect of ethanol-unleaded gasoline blends (E0,E10,E25,E35,andE65) computer interfaced, four-stroke single cylinder compression ignition engine. The said engine wasconverted to spark ignition and carburetion to suit ethanol fuel. A suitable provision was provided on theengine to vary the compression ratio thereby making the engine adaptable to operate at lowercompression ratios. The tests were performed by varying the ignition timing, equivalence ratio, andcompression ratio at a constant speed of 1500 rpm and at wide open throttle (WOT). Effect of ethanolunleadedgasoline blends and tests variables on engine torque and specific fuel consumption wereexamined experimentally. The results of this investigation, is believed, to contribute substantially to theknowledge, aimed to ensure a secure future energy.
https://www.ije.ir/article_71695_6566994fbcdb15e1ad6711b147c8c9a5.pdf
2008-04-01
97
106
Ethanol
Gasoline
Ignition Timing
Equivalence ratio
Compression Ratio
Variable Compression Ratio
performance
and Emissions
S.
Nawazish Mehdi
nawazishmehdi@yahoo.co.in
1
Mechanical Engineering, Muffakham Jah College of Engineering & Technology
AUTHOR
Syed
Yousufuddin
yousufuddin2k3@yahoo.co.in
2
Mechanical Engineering, JUBAIL UNIVERSITY COLLEGE
AUTHOR