International Journal of Engineering
Volume:20 Issue: 3, Dec 2007

In this paper an artificial society is being assumed as a multi agents system. A sugarscape model consisting of a cellular landscape of resources is used to form an interaction among the agents of the population. In the model, agents find the resources to survive. They are supposed to move and search and because of this movement, an evolutionary social behavior will develope. From model analysis view point this behavior should be parameterized and also optimized. To analyze the said assumption, each agent should gather and store as much sugar as possible to create an asset for itself. Hence, From the simulation result, the population be categorized based on the asset. In the society, wealth may be allocated based on the asset, gathered by the agents. The percentage of population who will possesses some percentage of the wealth is specified. The simulation shows that in an artificial life, it is possible to use the sugarscape model to optimize the behavior of a society, and the parameters of the model are predictable as well.

Image restoration is an essential preprocessing step for many image analysis applications. In any image restoration techniques, keeping structure of the image unchanged is very important. Such structure in an image often corresponds to the region discontinuities and edges. The techniques based on partial differential equations, such as the heat equations, are receiving considerable attention in image restoration. In this paper, a new algorithm is proposed for image restoration using partial differential equations applied on neighbors longer than one pixel. To better preserve edges in this technique, slant edges are considered in addition to vertical and horizontal edges. A number of experiments have been preformed to evaluate performance of the proposed method and to compare its performance with the existing algorithms, wiener and median filters. The results express the considerable superiority of the proposed methods.

The goal of this study is to introduce a statistical method regarding the analysis of specific latent data for regression analysis of the discrete data and to build a relation between a probit regression model (related to the discrete response) and normal linear regression model (related to the latent data of continuous response). This method provides precise inferences on binary and multinomial models which particularly in the case of small samples, has preference to maximum likelihood methods. The probit regression model for binary outcomes can be easily and precisely explained using different normal distributions for latent data modeling. Applying this approach and using Gibbs sampler method needs simulation of standard distributions such as multivariate normal distribution. Therefore, it can be easily implemented by many softwares and it provides a general method for analyzing binary (or polychotomous) response regression models.

The performance of components produced by conventional route of a thermo mechanical process and those produced by continuous casting is interesting from different aspects of economy and technology. The performance of products in their service depends on their properties which are strongly influenced by production routes. In the present work the hardness, tensile and tensile-impact behaviors of CuZn40Al1 alloys produced by continuous casting and extrusion were investigated. Micro structural features and fracture surfaces were studied by optical and scanning electron microscopy. Results showed that wrought samples exhibited higher absorbed energy than those of continuous cast samples. Reduction of impact velocity led to a higher absorbed energy in all samples. A systematic and meaningful relationship was observed between micro structural features and mechanical properties such as hardness, yield stress and ultimate tensile strength. Fractography investigations showed that fracture occurred with dimple formation in all cases.

Combined electrochemical and hydrothermal assisted by microwave was used for the preparation of copper phthalocyanin blue (Cu Pc) nanoparticles with sizes ranging from 5 to 35 nm. Phthalic anhydride, urea and ammonium molybdate catalyst were dissolved in aqueous solution of 1 M NH4Cl containing a small amount of lauric acid as capping agent to suppress the flocculation of pigment. Electrodes were a copper plate as anode and a graphite rod as cathode. The cell was irritated with microwave the solution was stirred and a potential about-0.34 V was applied to the electrolysis cell. The copper (II) ion generated by anodic dissolution of copper electrode reacts with other initial materials dissolved in NH4Cl solution to produce CuPc. The yield and purity of CuPc is increased and the reaction time and energy consumption are considerably decreased. The product was characterized by 13C NMR, UV-Vis, reflectance spectra, particle size measurement and elemental micro analysis. The procedure of CuPc preparation was optimized using a Taguchi experimental design.

Medium-pore (diameter ~ 6A) zeolites such as ZSM-5 and silicalite impregnated with Group VIII metals provide selective catalytic pathways for the conversion of synthesis gas to gasoline or olefins. Mössbauer and magnetic studies on these catalysts containing iron or iron plus cobalt are reported. The zeolites were impregnated with metal nitrate solutions, reduced, and carbided to yield showed Fe3+ type spectra. The ZSM-5 (14.7 % Fe) and Silicalite (13.6 % Fe) samples exposed to H2 (450˚C) showed an approximate 85% reduction to the metallic state. The carbided ZSM-5 (14.7 % Fe) revealed a spectrum of Hagg carbide (Fe5C2), an active component of the catalyst. The used catalysts showed mixtures of Hagg carbide (Fe5C2) and cementite (Fe3C). It is suggested that the selectivity of ZSM-5 (5.6 % Fe, 4.5 % Co) resulted from iron-cobalt alloy formation.

Along with high sensitivity in detecting gas, the response and recovery times of semiconductor gas sensors are of considerable importance for real life applications. In most cases, the recovery time is more than the response time. At the same time, water vapor present in the ambient, is chemisorbed on the tin oxide, SnO2 surface and the water molecules dissociate into hydroxyl species, which act as electron donors. In this research, we find that if the interference of absorbed moisture can be reduced by surface treatment with thiourea diluted solution, the recovery time and stability of tin oxide sensors improves, which makes them suitable in real life applications.

The rheological and filtration properties of drilling mud under down-hole conditions may be very different from those measured at ambient pressures and temperatures at the surface. This paper presents the results of an experimental investigation into the temperature and salinity and pH effects on drilling mud rheological and filtration properties. Results are given from tests on water base mud containing CMC polymer and XC polymer. Drilling fluid was investigated at three different temperatures (21.1°C, 48.9°C, 80°C) containing 8.165Kg/bbl bentonite. The drilling mud salinities in this study were fresh water (Ahwaz water: ppm: 400, Hardness: 120), 2000 ppm, 4000 ppm, 8000 ppm and 40000 ppm. It was found that pH of drilling mud should be kept at range of 8-10, because increasing pH of drilling mud will increase its rheological properties. The salinity and temperature effects show that as the salinity and temperature of drilling mud are increased the effectiveness of polymers in drilling mud will decreased. Moreover, they have a negative effect on filtration properties of drilling mud. In suspensions of sodium montmorillonite that are well dispersed and have low gel strength, both plastic viscosity and yield point decrease with increasing temperature.

The roles of the several parameters that influences railway track deterioration most, are examined in this research with a view to make railway track maintenance more effective and cost efficient. The results presented are based on a comprehensive study of railway track degradation on super structure, sub-structure and geometrical aspects. The changes in TQI (Track Quality Index), the track settlement and the average growth of track''s irregularity are considered to be the main track deterioration criteria from the aspects of track geometry,on the tracks sub-structure and super structure, respectively. In this research the sensitivity of the closely related parameters between, ballast conditions, subgrade compaction, rail-pad stiffness, rail types, sleeper spacing, initial track quality, tonnage, train speed, axle loads, and load cycles are studied. It is shown how one can control the rate of track deterioration by the verification and modification of the track structure, geometry and traffic parameters.