Moubed M.,Islamic Azad University at Ardakan |
Zare Mehrjerdi Y.,University of Yazd
International Journal of Engineering, Transactions A: Basics | Year: 2016
Inventory routing problems arise as simultaneous decisions in inventory and routing optimization. In the present study, vendor managed inventory is proposed as a collaborative model for reverse supply chains and the optimization problem is modeled in terms of an inventory routing problem. The studied reverse supply chains include several return generators and recovery centers and one collection center. Since the mathematical model is an NP-hard one, finding the exact solution is time consuming and complex. A hybrid heuristic model combining dynamic programming, ant colony optimization and tabu search has been proposed to solve the problem. To confirm the performance of proposed model, solutions are compared with three previous researches. The comparison reveals that the method can significantly decrease costs and solution times. To determine the ant colony parameters, four factors and three levels are selected and the optimized values of parameters are defined by design of experiments. © 2016, Materials and Energy Research Center. All rights reserved.
Emami-Meibodi M.,Islamic Azad University at Ardakan |
Elahifard M.,Islamic Azad University at Ardakan
Biofuels | Year: 2017
In this work the optimum ratio of syngas components and the optimum temperature, pressure, equivalence ratio and moisture content for different types of biomass are investigated for methanol synthesis according to the Gibbs free energy minimization calculations. Our results show the yield of methanol synthesis may be solely determined by the (Formula presented.) ratio in long ranges of temperature, pressure, (Formula presented.) and (Formula presented.). So, the produced syngas quality in the biomass gasification was evaluated according to the R1 parameter for 86 varieties of biomass. Herein, a new optimum temperature for the gasification process is defined and it is shown that this temperature, which is always preferred for commercial processing, is 800 and 1100 °C in 1 and 70 atm, respectively. Some of the best biomass varieties for methanol synthesis include mustard husks, tamarack bark, greenhouse-plastic waste and meat-bone meal; the first one shows the highest H2/CO ratio. © 2017 Informa UK Limited, trading as Taylor & Francis Group
Fattahi Ardakani A.,Islamic Azad University at Ardakan |
Alavi C.,Islamic Azad University at Ardakan |
Arab M.,Islamic Azad University at Ardakan
International Journal of Environmental Science and Technology | Year: 2017
Using methods to estimate the value of environmental goods seems to be essential for economic planning and moving toward development. In this paper, using methods of discrete payment vehicle (dichotomous choice), i.e., single-bounded and Double-Bounded Dichotomous Choice, the value of air pollution in Tehran and households’ willingness to pay to improve air quality, in four selected regions (Shahr-e-Ray, Shoosh, Haft-e-Tir and Tajrish) is estimated and the corresponding results of these two techniques were compared. The results showed that the total value of air quality improvement, calculated through two techniques of Double-Bounded and Single-Bounded Dichotomous Choice were, respectively, 2,398,657,500 and 1,492,566,000 thousands Rials (1USD = 35,000R) in a year and weighted mean of each citizen’s willingness to pay to improve air quality, calculated through these two methods was estimated to be 282,192 and 175,596 Rials in a year, respectively. Considering the annual damage to health, for any 1% increase in pollutants and yearly cost of pollution reduction which are, respectively, 1,199,000,000 and 7,336,000,000 thousands Rials, it was determined that citizens’ willingness to pay through two methods includes 20 and 30% of the cost of pollution control, respectively, while 70% of pollution is due to mobile sources. However, citizens’ low willingness to pay is attributed to citizens’ distrust of government policies as well as their ignorance of the harmful effects of air pollution. In general, the results of this study, with regard to the cost of pollution from Single-Bounded Dichotomous Choice are closer to actual market conditions. © 2017, Islamic Azad University (IAU).
Meybodi R.R.,Payame Noor University |
Mehrjardi M.Z.,Islamic Azad University at Ardakan |
Rahmatabadi A.D.,University of Yazd
Industrial Lubrication and Tribology | Year: 2017
Tilt angle effects as design parameters of noncircular bearings were studied, on the linear dynamic analyses of micropolar lubricated circular, 2, 3, and 4 lobe journal bearings. Considering the micropolarity of the lubricant, Reynolds equation was modified and was solved using generalized differential quadrature method. Results showed that tilt angle has significant impact on the steady state and stability performance of lobed journal bearings. It may be selected to enhance the performance of rotor-bearing system, while all other lubricant properties and noncircular bearing design parameters are kept fixed. Also, among the three types of bearings, the dynamic performance of two lobe bearing were more affected by the tilt angle variation.
Elahifard M.,Islamic Azad University at Ardakan |
Fazeli E.,Payame Noor University |
Joshani A.,Shahid Beheshti University |
Gholami M.,Sharif University of Technology
Surface and Interface Analysis | Year: 2013
Direct CO dissociation is seen the main path of the first step in the Fischer-Tropsch Synthesis (FTS) on the reactive iron surfaces. Cu/Fe alloy film is addressed with various applications over face-centered-cubic (fcc)-Cu and body-centered-cubic (bcc)-Fe in the FTS, i.e. preventing iron carbide formation (through direct CO dissociation) by moderating the surface reactivity and facilitating the reduction of iron surfaces, respectively. In this study by density functional theory, the stable configurations of CO molecule on various Cu/Fe alloys over fcc-Cu(100) and bcc-Fe(100) surfaces with different CO coverage (25% and 50%) have been evaluated. Our results showed that the ensemble effect plays a fundamental role to CO adsorption energy on the surface alloys over bcc-Fe(100); on the other hand, the ligand effect determines the CO stability on the fcc-Cu(100) surface alloys. CO dissociation barrier was also calculated on the surface alloys that showed although the CO dissociation process is thermodynamically possible on the more reactive surface alloys, but according to their high barrier, CO dissociation does not occur directly on these surfaces. Copyright © 2013 John Wiley & Sons, Ltd. Copyright © 2013 John Wiley & Sons, Ltd.
Azimzadehirani M.,Sharif University of Technology |
Elahifard M.,Islamic Azad University at Ardakan |
Haghighi S.,Pasteur Institute of Iran |
Gholami M.,Sharif University of Technology
Photochemical and Photobiological Sciences | Year: 2013
TiO2-based photocatalysts are seen as the most common agents for the photodegradation of bacteria. In this study, AgCl/TiO2, hydroxyapatite(Hp)/AgCl/TiO2, AgI/TiO2, and Hp/AgI/TiO2 were prepared by the deposition-precipitation method on P25 TiO2 nanoparticles and were characterized by XRD, SEM, FT-IR, EDX and BET methods. The prepared composites showed high efficiency for the inactivation of Escherichia coli (E. coli) bacteria under visible light and in dark media with different catalyst amounts of 12 and 24 mg, respectively. In less than 30 min, AgI/TiO2, prepared by the combination of cationic surfactant and PVPI2, disinfected 1 × 107 colony-forming units of E. coli completely. However, AgCl/TiO2 was not stable under the same conditions. Hp was added to AgCl/TiO2 and AgI/TiO2 to extend the antibacterial effect to dark media. Hp/AgCl/TiO2 showed desirable disinfection capabilities under visible light irradiations that function in less than 30 min. During the time interval when the inactivation was complete, the photocatalytic activity of Hp/AgCl/TiO2 under visible light was maintained effectively without the destruction of AgCl. Hp/AgCl/TiO2 and Hp/AgI/TiO2 were found to prevent bacteria from growing during 3 h in the dark. The antibacterial properties of Hp composites in dark environments are mainly due to the strong linkage between Hp and the cell wall which limits the nourishment of bacteria, while under visible light, in addition to the photocatalytic process, the sense-shoot phenomena and the adsorption effects can be accepted. © 2013 The Royal Society of Chemistry and Owner Societies.
Abyar F.,Islamic Azad University at Ardakan |
Farrokhpour H.,Isfahan University of Technology
Journal of Photochemistry and Photobiology B: Biology | Year: 2016
In this work, the gas phase ionization energies and photoelectron spectra of four important conformers of Vitamin C were calculated. Symmetry adapted cluster/configuration interaction methodology employing the single and double excitation operators (SAC-CI SD-R) along with D95 ++(d,p) basis set were used for the calculations. Thermochemistry calculations were also performed on all possible conformers of Vitamin C to find the relative stability of conformers in the gas phase. The calculated ionization bands of each conformer were assigned by calculating the contribution of natural bonding orbital (NBO) in the calculated canonical molecular orbitals involved in the ionization. SAC-CI calculations showed that the first ionization band of Vitamin C is related to the π electrons of C=C bond of the ring of molecule although, there is the lone electron pairs of oxygen atoms and π electrons of C=O bond in the molecule. © 2016 Elsevier B.V. All rights reserved.
Dehghan A.A.,University of Yazd |
Barzegar A.,Islamic Azad University at Ardakan
Energy Conversion and Management | Year: 2011
Transient thermal performance behavior of a vertical storage tank of a domestic solar water heating system with a mantle heat exchanger has been investigated numerically in the discharge/consumption mode. It is assumed that the tank is initially stratified during its previous heat storing/charging operation. During the discharging period, the city cold water is fed at the bottom of the tank and hot water is extracted from its top outlet port for consumption. Meanwhile, the collector loop is assumed to be active. The conservation equations in the axis-symmetric cylindrical co-ordinate have been used and discretised by employing the finite volume method. The low Reynolds number (LRN) k - ω model is utilized for treating turbulence in the fluid. The influence of the tank Grashof number, the incoming cold fluid Reynolds number and the size of the inlet port of the heat storage tank on the transient thermal characteristics of the tank is investigated and discussed. It is found that for higher values of Grashof number, the pre-established thermal stratification is well preserved during the discharging operation mode. It is also noticed that in order to have a tank with a proper thermal performance and or have least mixing inside the tank during the consumption period, the tank inflow Reynolds number and or its inflow port diameter should be kept below certain values. In these cases, the storage tank is enabling to provide proper amount of hot water with a proper temperature for consumption purposes. © 2010 Elsevier Ltd. All rights reserved.
Taghizadeh-Mehrjardi R.,Islamic Azad University at Ardakan
Archives of Agronomy and Soil Science | Year: 2015
This study evaluates the performances of a combination of genetic programming and soil depth functions to map the three-dimensional distribution of cation exchange capacity (CEC) in a semiarid region located in Baneh region, Iran. Using the conditioned Latin hypercube sampling method, the locations of 188 soil profiles were selected, which were then sampled and analyzed. In general, results showed that equal-area quadratic splines had the highest R2, 89%, in fitting the vertical CEC distribution compared to power and logarithmic functions with R2 of 81% and 84%, respectively. Our findings indicated some auxiliary variables had more influence on the prediction of CEC. Normalized difference vegetation index (NDVI) had the highest correlation with CEC in the upper two layers. However, the most important auxiliary data for prediction of CEC in 30–60 cm and 60–100 cm were topographic wetness index and profile curvature, respectively. Validation of the predictive models at each depth interval resulted in R2 values ranging from 66% (0–15 cm) to 19% (60–100 cm). Overall, results indicated the topsoil can be reasonably well predicted; however, the subsoil prediction needs to be improved. We can recommend the use of the developed methodology in mapping CEC in other parts in Iran. © 2015 Taylor & Francis
Ardakani A.F.,Islamic Azad University at Ardakan
International Journal of Environmental Science and Technology | Year: 2016
Although intangible effects on natural environments are not visible and only become apparent over a long period of time, they may cause irreparable damages whose estimation is not always feasible. However, people’s willingness to pay (WTP) for the prevention of adverse environmental effects can be determined. The present study addresses the issue of the effect of dust in Yazd-Ardakan Plain. It aims at the valuation of local people’s WTP in order to prevent extra-regional intangible effects of dust in Yazd-Ardakan Plain in 2010. The study was based on data collected from 479 questionnaires completed by people in the affected area. Factors affecting local people’s WTP and their expected WTP were estimated by logit regression model. It was revealed that among the studied variables, income, education, and environment importance had significant positive effects, and that household size, type of residence, and bid had significant negative effects on people’s WTP. Also, the WTP for the conservation of the region was estimated as to be 93.4 billion Iranian Rials (IRR) per year. In other words, it is necessary to invest at least 93.4 billion IRR to prevent the adverse impacts of dust on the plain. Given the 183 billion IRR expenditure for stabilizing sand in the region and the estimated 93.4 billion IRR protection value for the plain, 50 % of expenses would be paid by people living in the region, which paves the way for the fulfillment of conservation programs by experts using public contributions. © 2016, Islamic Azad University (IAU).