International Journal of Engineering
Volume:30 Issue: 8, Aug 2017

Abstract Technical limitations in image capturing usually impose defective, such as contrast degradation. There are different approaches to improve the contrast of an image. Among the exiting approaches, un-sharp masking is a popular method due to its simplicity in implementation and computation. There is an important parameter in un-sharp masking, named gain factor, which affects the quality of the enhanced image. In this paper, a new adaptive un-sharp masking method is proposed. In the proposed method gradient variation of the image is used to estimate the gain factor for un-sharp masking. Gradient variation of an image can provide information about the image contrast. Subjective and objective image quality assessments are used to compare the performance of the proposed method both with the classic and the recently developed un-sharp masking methods. The experimental results show the superiority of the proposed method compared to the existing methods in image enhancing using un-sharp masking.

Abstract Bit swapping linear feedback shift register (BS-LFSR) is employed in a conventional linear feedback shirt register (LFSR) to reduce its power dissipation and enhance its performance. In this paper, an enhanced BS-LFSR for low power application is proposed. To achieve low power dissipation, the proposed BS-LFSR introduced the stacking technique to reduce leakage current. In addition, three different architectures to enhance the feedback element used in BS-LFSR was explored. The pass transistor merged with transistor stack method yielded a better reduction in power dissipation compared to pass transistor design and NAND gate design. The BS-LFSR was designed in Mentor Graphic – TSMC Design Kit Environment using 130nm complementary metal oxide semiconductor (CMOS) technology. The proposed 4-bit BS-LFSR achieved an active area of 1241.1588um2 and consumed only 53.8844nW with total power savings of 19.43%. The proposed design showed superiority when compared with the conventional LFSR and related work in reducing power dissipation and area.

Abstract In this paper, impacts of various uncertainties such as random outages of generating units and transmission lines, forecasting errors of load demand and wind power, in the presence of Demand response (DR) programs on power generation scheduling are studied. The problem is modelled in the form of a two-stage stochastic unit commitment (UC) which by solving it, the optimal solutions of UC as well as DR are obtained. Generating units’ constraint, DR and transmission network limits are included. Here, DR program is considered as ancillary services (AS) operating reserve which is provided by demand response providers (DRPs. In order to implement the existent uncertainties, Monte Carlo (MC) simulation method is applied. In this respect, scenarios representing the stochastic parameters are generated based on Monte Carlo simulation method which uses the normal distribution of the uncertain parameters. Backward technique is used to reduce the number of scenarios. Then, scenario tree is obtained by combining the reduced scenarios of wind power and demand. The stochastic optimization problem is then modelled as a mixed-integer linear program (MILP). The proposed model is applied to two test systems. Simulation results show that the DR improves the system reliability and also reduces the total operating cost of system under uncertainties.

Safety risk study on road transportation of hazardous chemicals is a reliable basis for the government to formulate transportation planning and preparing emergent schemes, but also is an important reference for safety risk managers to carry out dangerous chemicals safety risk managers. Based on the analysis of the transport safety risk of dangerous chemicals at home and abroad, this paper studied four main factors influencing the safety risk of road transportation. In order to study the reliability of the whole road transport system and take into account the dynamic changes of the safety risk, this paper presents the dynamic fault tree and Bayesian network hybrid method to identify and evaluate the dynamic safety risk of the road transportation of dangerous chemicals. Finally, the feasibility of the model is verified by the case study of road transportation of liquefied natural gas in a real enterprise.

In this article, a new combined approach of a decision tree and clustering is presented to predict the transmission of genetic diseases. In this article, the performance of these algorithms is compared for more accurate prediction of disease transmission under the same condition and based on a series of measures like the positive predictive value, negative predictive value, accuracy, sensitivity and specificity. The results show that support vector machine algorithm outperformed the other two simple algorithms and the neural network and genetic algorithms offered better prediction at the end, while the proposed combined approach is developed using different parameters and outperformed the simple methods.

Social responsibility is a key factor that could result in success and achieving great benefits for supply chains. Responsiveness and reliability are important social responsibility measures for consumers and all stakeholders that strategists and company managers should be concerned about them in long-term planning horizon. Although, presence of uncertainties as an intrinsic part of supply chains could adversely affect the best set plans by field experts. Accordingly, uncertainty of parameters and uncertainties caused by disruptions should be regarded in planning process of networks to prevent unpredictable negative consequences of such uncertainties for all echelons of supply chain. Based on enumerated matters, the aim of this paper is to design a reliable multi-echelon closed loop supply chain network model that maximizes social responsibility while minimizing fixed establishing and variable processing costs of network design. To cope with uncertainty of parameters, stochastic programming is applied and an effective reliable modelling method is employed to appropriately control unpleasant economic impacts of disruptions. Notably, an efficient robust programming method is applied to give the decision makers the capability to control level of risk-averseness of decisions while modelling uncertain parameters. Finally, the proposed model is solved and its outputs are analyzed on the basis of generated test problems which shows correct performance and applicability of extended model in real world problems.

Physical and mechanical regularities in the effect of certain processing operations on the shape and roughness of the hydraulic cylinder surface are found. The mechanisms of the spatial self-organization of the relief and surface of bearings under conditions of false brinelling are summarized and analyzed. The data obtained can be used for further scientific generalization or prediction and diagnostics of the surface condition of load-carrying and support elements of mechanical systems under study.

The aim of this work is the application of the phase variation in vibration signal for fault detection on rotating machines. The vibration signal from the machine is modulated in amplitude and phase around a carrier frequency. The modulating signal in phase is determined after the Hilbert transform and is used, with the Fast Fourier Transform, to extract the harmonics spectrum in phase. This method is first validated on a simulator of vibration then used for detecting potential faults on a rotor of a centrifugal compressor.

Buried pipes in the modern societies are considered as lifelines with a vital and essential role in the human life cycle. The performance of buried pipes is affected by many factors such as ground surface subsidence. In this paper, the effect of subsidence on pipelines is investigated using a three-dimensional numerical modeling developed in FLAC3D software for four types of most commonly used pipes. The numerical results showed that ductile iron, steel, and polyethylene pipes with a diameter of 200 mm are stable in the presence of ground subsidence whereas the asbestos pipes at depths of 1 and 1.5 m are not stable; and thus should be buried deeper. In this regard, polyethylene pipes with equal diameter are recommended instead of asbestos pipes due to the high excavation and earth-filling costs and also environmental problems involved in the implementation of asbestos pipes.

In this paper, an effective image demosaicking algorithm, which is based on the correlation among the three primary colors, is proposed for mosaic image with Bayer color filter array (CFA). To reduce the distortion and improve the reconstruction quality, the proposed interpolation method makes full use of the brightness information and the edge information. We design several filters with size of 5×5, 3×5, and 5×3 firstly, and then improve the bilinear algorithm with a correction value. Simulations on 24 Kodak photos demonstrate that our proposed method outperforms the other two methods in average composite peak signal-to-noise ratio (CPSNR) and visual perception. The biggest advantage of the proposed method is that it fully utilizes the correlation among RGB channels.

Iran has great potential in utilizing solar energy. In order to maximize the amount of absorbed solar radiation to absorber surfaces, the surfaces should be installed at a suitable angle slope to the horizon that is discussed in this article. The calculations performed in this study was done using MATLAB software. In this study, radiation received on the ground in 31 provincial capitals of the country for 12 months of the year has been modeled. Then, the optimum tilt angle of absorbent surfaces with the maximum amount of radiation received on the surfaces of the absorber is estimated. Finally, after validating the results, using available software in the field of GIS, atlas map of optimum tilt angle with respect to the horizon for the installation of solar absorber surfaces and amount of absorbed solar radiation on surface mounted in the optimum tilt angle for Iran was presented for 12 months. It is observed that optimum tilt angle varies throughout the year between -10 to 62 degrees. The minimum value of optimum tilt angle in different months is related to North West provinces. The lowest amount of solar radiation is received on Caspian littoral, and its value varies between 9 and 19 MJ per square meter per day for different months. The highest amount of radiation in region of the provinces Yazd and Isfahan is received and its value varies between 19 to 31 MJ per square meter per day for different months. The figures presented in this paper eliminate the need for estimating clearness index, optimum tilt angle, and corresponding solar radiation in cities and regions on which no information is available. It provides researchers with the aforementioned values based on the mean of values of adjacent regions.

Graphene is a monolayer carbon atoms discovered in the recent past which has inspired researchers in a wide range of applications. It has a surface area as high as 2630 m2/g and thermal conductivity value of 3000 W/mK-1 at room temperature. It is chemically the most reactive form of carbon with one carbon atom exposed to reaction from each side. Stable dispersion of graphene was achieved using sodium dodecyl sulfate surfactant. Graphene nanofuel was prepared by dispersing of graphene in simarouba methyl ester blend with diesel. The dispersion was characterized using the ultra violet visible spectrometry. The performance, combustion and emission characteristics were studied on a single cylinder, water cooled, direct injection, four stroke computerized diesel engine test rig. The characteristics were studied for three different dosing levels of graphene nanoparticle and three different fuel injection timings. It resulted in improved brake thermal efficiency, reduced unburnt hydrocarbon and carbon monoxide emission. The addition of graphene nanoparticles and advancing the injection timing has resulted in a significant reduction in the combustion duration and a marginal increase in the peak cylinder pressure at all operational loads.

A number of considerations should be taken into account in design stage to avoid the foregoing malfunctions of vertical silos containing ore concentrate. One of the silo problems is obstruction at the outlet which blocks the material flow. There are procedures, depending on the material properties and silo dimensions, to solve this problem. A common way is impacting the silo wall by manual hammering or pneumatic impacting. In the present work, the hopper of a laboratory silo containing the magnetite concentrate, for obstruction solution is impacted by single ball. Impacts lead to the bulk fracture and material discharge. Capturing the new arc profile after discharge and registering the required number of impacts which provide the continuous material flow helps us to determine the optimum impacts. Results show that the wall displacement due to the impact is a governing factor in obstruction solution and the best impact position is near the outlet. It is also concluded that at a constant kinetic energy the impacts by higher mass balls are more effective than the impacts by higher velocity balls.

Nanofluids are the heat transfer fluids having remarkable thermal properties. The paper presents the experimental analysis of thermal conductivity, density, specific heat and viscosity of multiwalled carbon nanoparticles dispersed in water at various temperatures and particle concentrations. To examine the forced convection heat transfer of Multiwalled Carbon Nanotubes (MWCNT)-water nanofluid, the assessment of thermophysical properties are necessary. The two-step method was used to prepare the nanofluids with gum arabic surfactant. The thermophysical properties were measured using different volume concentrations (i.e. 0 – 0.9 vol.%) of nanoparticles and various temperatures (i.e. 30°C to 70°C). The thermal conductivity, specific heat, density and viscosity were measured with the help of KD2 Pro Thermal Property Analyser, Differential Scanning Calorimeter, KEM-DA 130N - Portable density meter, Brookfield LVDV-III ultra-programmable viscometer. The experiment found an enhancement in thermal conductivity and specific heat with rise in temperature whereas viscosity and density decreases with increase in temperature. On the other hand the thermal conductivity, viscosity and density increases with increase in MWCNT’s concentration but the specific heat was found to diminish with a rise in particle concentration.

Interatomic potentials, which describe interactions between elements of nanosystems, are crucial in theoretical study of their physical properties. We focus on two well known empirical potentials, i.e. Tersoff's and Brenner's potentials, and compare their performance in calculation of thermal transport in carbon nanotubes. In this way, we study the temperature and diameter dependence of thermal conductivity of single walled armchair carbon nanotube by using the mentioned interatomic potentials. We take advantage of direct non-equilibrium molecular dynamics simulation, which well resembles the experimental set up for thermal conductivity measurement. The results show that increasing the temperature increases the conductivity in contrast with diameter growth which decreases the thermal conductivity. It is important to note that both interatomic potentials describe the system behavior very well, however they lead to different conductivity values. It is found that the difference between the performance of studied potentials can be seen more obviously in longer tubes. We also observe a peak in thermal conductivity by increasing system temperature. System is deformed at T≈1000 K, when Tersoff's potential is employed for description of interactions. While its instability occurs at higher temperature (T≈1600 K), when we try to simulate system by Brenner's potential.

This paper aims to develop a writing robot by recognizing the speech signal from the user. The robot arm constructed mainly for the disabled people who can’t perform writing on their own. Here, dynamic time warping (DTW) algorithm is used to recognize the speech signal from the user. The action performed by the robot arm in the environment is done by reducing the redundancy which frequently faced by the robot arm with high accuracy in both velocity and position in its own trajectory.

This paper presents an original interactive analysis method consisting of mathematical calculation based on theoretical mechanics and mechanics of materials, and dynamics simulation for quantifying outrigger reaction forces of a kind of hydraulic mobile crane, aiming to avoid the eventualities during normal operation as far as possible, for example, tipping-over. First, a three dimensional dynamic model is established and the statically indeterminate problem of mechanics of materials is employed in the mathematical calculation. Then, the multi body dynamics simulation is investigated and the corresponding force-time curves are generated simultaneously. Finally, the validity of the proposed method is proven by comparing the amplitudes of the two kind of force-time plots upon the model. Thus, the bearing load of the crane can be limited to a feasible range for static stability or avoiding outriggers collapse.

In this paper, the heat transfer to the fluid, passing through the double forward facing step (FFS) channel with square obstacle is enhanced by Taguchi’s S/N ratio analysis. Flow through the forward facing step channel has a wide range of applications in thermal systems due to its flow separation and subsequent reattachment, which in turn enhances the heat transfer. Flow separation and reattachment mainly depends on the channel geometry, obstacle and flow parameters. Hence, in this study, step height in the channel, obstacle size, Reynold’s number and gap between the obstacle and step are included as control paramters in the S/N ratio analysis for maximizing the heat transfer. These parameters are varied through three levels of values and L9 orthogonal array is employed. Numerical simulation technique is applied to analyze the L9 cases through computational fluid dynamics code. From the simulation, the rise in temperature at the channel exit with reference to the inlet is predicted. The best values for the identified control parameters conclude to a temperature raise of about 2.86°C. The optimum result obtained from the S/N ratio analysis is also compared with response surface methodology technique. Finally, analysis of variance (ANOVA) is conducted and identified that step height and flow Reynold’s number affect the heat transfer by about 79 and 19%, respectively.

The aims of this study are to enhance the performance of a solar chimney power plant (SCPP), investigate utilization of thermal energy storage (TES) and analyze the environmental impact of the SCPP in providence of Isfahan, Iran. To achieve these goals, multi-stage numerical simulations during twenty-four hours of a day are performed in climate condition of Isfahan province (central region of Iran). Isfahan province has proper environmental condition for utilization of SCPP as a source of electricity and the environmental crises during the last decade in Iran have made utilization of green power plants a necessity. Performance enhancement of the SCPP is carried out by improvement in geometrical characteristics of collector and chimney of the SCPP. Considered factors for performance enhancement of SCPP are height, ceiling slop and radius of the collector as well as height, radius and throat shape of the chimney. Then a TES is employed to produce power in the absence of solar radiation in new proposed optimal configurations. In continue carbon dioxide emission and water consumption of enhanced configurations of SCPP are compared with shale gas, coal, hydroelectric and biomass power plants for same output power to investigate environmental impact of the SCPP. Results illustrate that improved collector of the SCPP increases the output power by almost 139% and enhanced chimney of the SCPP improves performance of the power plant by approximately 68.1%. Results also show that the SCPP with the TES would produce power during night hours in a stable range and TES has higher performance in SCPP with optimal proposed configurations. The results confirm that the SCPP is a proper choice for power generation in province of Isfahan (central region of Iran) and the enhanced SCPP with TES improves the output power range and environmental benefits considerably.

Electrohydrodynamic effect on natural convection in horizontal channels is investigated from a numerical point of view. The EHD effect is induced by narrow strip electrodes placed at the bottom wall of the channel. The channel is subjected in a first stage only to the electric forces, and in a second stage to the simultaneous action of a temperature gradient and an electric field. The interactions between electric field, flow field and temperature field are analyzed. It can be concluded that charge density distribution, flow pattern and temperature distribution are substantially affected by the arrangement of the electrodes; in fact four different arrangement were treated. The effect of pure electroconvection on charge density distribution and on flow pattern was studied. A periodic flow corresponding to particular values of electric Rayleigh was observed, then the impact of combined electro-thermo convection on heat transfer was undertaken in a second step and it was noted that the optimum arrangement of the electrodes provides an increase in heat transfer of up to 13%. The effect of the applied electric forces is also studied in order to highlight the importance of putting compromise between the supplied voltage and arrangement of the electrodes. Finally, a study of optimized configuration of electrodes was achieved.

Push back design as a complex task, is one of the major steps in the open pit mines planning. Push backs can be generated by varying economic factors such as commodity price, mining cost, processing cost, etc. Another important issue in generating push backs is grade uncertainty, which can cause the problem be more complex. Conventional methods of push back design ignore grade uncertainty. To overcome this, “Grade Parameterization using Variance Algorithm” (GPVA) can be implemented. In this paper, an attempt was made to utilize GPVA in a hypothetical two-element deposit with the aim of minimization grade uncertainty effect on push backs design. Finally, the same example was solved using Whittle algorithm, the results indicate the superiority of the GPVA.