Search published articles


Showing 18 results for Andy


Volume 3, Issue 2 (Summer 2019)
Abstract

In this paper, for control Voltage of two chamber Microbial fuel cell, two-type PI controller and MPC controller are used. For this purpose, two compartments of the model presented by Esfandyari  et al. [1, 2] have been used to model the microbial fuel cell. Then, based on this model, a classic PI controller based on the internal model and a MPC controller was designed and implemented. Based on the designed controllers, it was adjusted by adjusting the flow rate of the substrate to changes usually introduced in turbulence, such as the concentration of input to the substrate, or the effect of the uncertainty in the parameters of the process model, such as rmax and Ks. The results show that the MPC controller has a better performance compared to the classic PI controller.
 

Volume 4, Issue 1 (Spring 2020)
Abstract

Research subject:
Zinc is one of the most dangerous organic components in industrial wastewaters, which pollutes the environment as a result of human activities and various industrial operations. In the present study, the adsorbent prepared from Gracilaria Corticata algae was used for the first time to recover and remove heavy metal zinc and equilibrium study of the process were done.
Research approach:
In the current work, the effect of important parameters such as initial pH of solution, adsorbent dosage and contact time were investigated on the adsorption efficiency of the process. Additionally, Langmuir and Freundlich two-parameter adsorption isotherm models were used to model the equilibrium of zinc adsorption.
Main results:
The results showed that according to the calculated correlation coefficient, Freundlich isotherm was better than the Langmuir in fitting the experimental data. The highest point-to-point correlation coefficient for adsorbent percentage was achieved at 3 g/ml adsorbent dosage with contact time of min 360 and pH=7 and the lowest one was at 4 g/ml adsorbent dose with contact time of min PH=360 and 7. However, the highest adsorption rate was observed for the adsorbent dosage of 4 g/ml with contact time of 420 min at pH=9 and the lowest adsorption percentage was achieved at the adsorbent dosage of 2 g/ml with contact time of 300 min and pH=5. The maximum and minimum adsorption percentages were 76.88 mg/g and 49.25 mg/g, respectively

Volume 5, Issue 2 (Summer 2021)
Abstract

Synthesis gas is a mixture of hydrogen gas and carbon monoxide, which usually contains carbon dioxide as an additive. This gas is the raw material in the production of many basic materials of the petrochemical industry such as methanol. Various raw materials have been used to produce synthetic gas, including natural gas (methane), hydrocarbons, and coal. This gas is also very suitable as an intermediate material for the production of industrial products, and depending on the reaction conditions and catalysts used, different chemicals may be produced in large industrial units. Modeling a synthesis gas production reactor as the heart of an operating unit in the petrochemical industry is of particular importance. Simulation of refinery units is always associated with many problems due to the complexity of the process and the lack of proper kinetics. In recent years, software such as Span Plus has been used to simulate and study refinery processes, which in this regard have to some extent facilitated and achieved the appropriate. In this research, the synthesis gas production unit is simulated with two methods of steam reforming and partial oxidation method using Aspen Plus V8.4 software. By examining parameters such as conversion rate, hydrogen to CO ratio, reactor temperature and pressure during the production process and other variables, the simulation results show that after adjusting the reaction coefficients, parameters such as inlet feed temperature, reactor length and time Residues affect the production of desired products that the use of steam reforming in terms of production of synthetic gas has a higher efficiency than the partial oxidation system.

Volume 6, Issue 3 (Summer 2020)
Abstract

Aims: Helicobacter pylori is a bacterium that colonizes the gastric mucosa and is the main cause of gastritis as well as ulcer and gastric cancer. Due to the clinical significance and international increase in H. pylori multidrug resistance, it is necessary to search for new strategies improving eradication rates. Natural compounds have been demonstrated to have antimicrobial effect and the ability to restore the efficacy of conventional drugs. The objective of this work was to evaluate the antimicrobial effect of the hydroalcoholic extract of Curcuma longa L. (Cu) against H. pylori isolates.
Materials & Methods: The minimum bactericidal concentration of the extract was determined by means of the MTT assay; also, the combination and dose reduction indices for levofloxacin (LVX), metronidazole (MET), and rifampicin (RIF) antimicrobial agents were determined by checkerboard format. Interaction analysis was performed using the CompuSyn program.
Findings: About 90% of H. pylori isolates studied (9/10) were sensitive to the hydroalcoholic extract. Synergism was observed in more than 50% of Cu-LVX, Cu-MET, and Cu-RIF combinations. Additionally, for different concentrations of the extract, reduction rates in antimicrobial agents were determined to be between 0.5 and 360 times.
Conclusions: The hydroalcoholic extract of turmeric showed a good potential to be used as an antimicrobial agent in the treatment of H. pylori infection, either alone or in combination with antibiotics used, suggesting the renewal of the effectiveness of conventional antimicrobials in reducing the phenomenon of antimicrobial resistance.

Volume 7, Issue 1 (No.1 (Tome 29), (Articles in Persian) 2016)
Abstract

Assessment of the English proficiency of applicants of entry into postgraduate studies, undeniably, is of utmost importance. Nationally speaking, the current status of the English test administered by the National Organization of Educational Testing (NOET) in Iran has been a topic of heated contention in recent years. This study purports to investigate the validity of the Iranian English proficiency test for Ph.D. admission purposes adopting the assessment use argument as the main framework for its validation research. To this end, the required data were collected from the relevant stakeholders of the test, namely applicants of the test, experts in educational assessment and language testing, and test readiness instructors. Structured interviews and focus groups were conducted and the acquired data were analyzed using the qualitative content analysis approach. Most prominent themes that emerged from the data in addition to a number of relevant representative quotes constituted the major findings of this study. The results revealed that the test is in need of major revisions in some parts, and further modifications are deemed as necessary. In the final section, summary of the results along with suggestions for optimization of the test are put forth. Keywords: Iranian Ph.D. admission English proficiency test, test validation, assessment use argument

Volume 10, Issue 2 (Spring 2019)
Abstract

Conventional wastewater treatment systems are not capable of removing phosphorus effectively. The entry of phosphorus into water resources leads to the formation of an Eutrophication phenomenon. One of the methods for phosphorus removal is the use of microalgae. In this way, besides helping with advanced sewage treatment, it can produce algae with many applications. The purpose of this study was to determine the simultaneous and to compare the phosphorus removal (rate of phosphorus) and Spirulina biomass production in a photobioreactor, using two kinds of treated sewage. The experiments were carried out with the manufacture of a photobioreactor and air injection by means of a fine bubble diffuser into sewage-containing reactors. The light source in this test was designed as fluorescent light bulbs and alternating radiation. Urban wastewater effluent and refined sewage were used as a culture medium in a photobioreactor. The amount of phosphorus in the purified sewage was measured by spectrophotometry at a wavelength of 690nm. The phosphorus removal and algal biomass production were measured in different culture medium containing wastewater with various concentrations of phosphorus. The initial concentrations of phosphorus in refined urban sewage and sanitary sewage were 1.96 and 0.4mg L-1, respectively. Phosphorus removal during microalgae cultivation with municipal wastewater and sanitary sewerage (removal of phosphorus) for 8 days, was 71.9% and 37%, respectively. Biomass production in this time were 0.18 and 0.025g/l, respectively. By decreasing the concentration of phosphorus in the wastewater, the amount of biomass production and (removal of) phosphorus removal decreased. Treated domestic and sanitary sewage can be injected directly, without prior treatment, in photobioreactor and it is possible to remove phosphorus and to produce algal biomass.


Volume 10, Issue 4 (Fall 2019)
Abstract

Diatoms biosilica shell, frustule, is substitute biostructures to mesoporous silica particles, which possesses their wide surfaces, nano-diameter porosity, mechanical strength, and thermal stability, optical capabilities, and the ability to bind to biomolecules can be used in biosensing applications. In this study, diatom species called Chaetoceros muelleri, was used for the fabrication of the Fe2O3-Au-Biosilica magnetic package. After micro-algae cultivation, the synthesis of gold nanoparticles (AuNPs) on silica walls was carried out using the bio-synthesis method, which evaluations have demonstrated the continuous formation of spherical AuNPs on the walls and its surfaces. After this step, the magnetic iron oxide nanoparticles were attached to the silica surface of the diatom, this, in turn, leads to system guiding using a magnetic field. Surface modification of diatoms magnetic complex, by using the APTES, allowed the attachment of fluorescence Rhodamine and the Herceptin antibody (Trastuzumab) to the structure. As well as the attachment of the fabricated system to target cells (SKBR3) was confirmed by fluorescence microscopic analysis. The results of this study indicate the ability and specificity of the diatom silicone shell as a "multipurpose" package for diagnostic and therapeutic activities.

Volume 13, Issue 4 (winter 2013 2014)
Abstract

In the economic literature, inflation is one of the most important factors influencing income inequality. Since Iran as a developing country has frequently been facing with high and volatile inflation rates, the study of the effect of inflation on income inequality is of considerable importance. Despite the importance of the issue, the few studies that have dealt with this subject have not derived same result, so the effect of inflation on income inequality remains paradoxical. However, the economic studies in recent decades confirm the nonlinear relationship between inflation and income inequality. Inspired by these studies, we investigate the nonlinear effect of inflation on income inequality during 1971-2006. Likewise, we examine the Granger causality relationship between inflation and income inequality by using “Toda & Yamamoto” and “Error correction” procedures during 1971-2007.

Volume 14, Issue 1 (4-2014)
Abstract

- In this study, the shrinkage behavior of knitted fabrics during drying is studied .To this end, a model is presented to predict the knitted fabric length changes during the drying process. In order to model the shrinkage behavior, a 1DOF model consisting of a mass, a linear spring and a linear dashpot was used. Considering that the fabric is wet, mass is time dependent and Three-order Straight Forward Expansion method is used to solve nonlinear equations of motion. The results of the model were compared with the experimental results of five samples with different courses density. The results show that the proposed model is capable to predict the length changes of the center of the mass during the process of drying and after that. Error rate is about ten percent for the samples with less Loop length. But by increasing the length of the loop, error rates increases.

Volume 14, Issue 1 (spring 2014 2014)
Abstract

The substantial share of informal employment in Iran, on the one hand and the growing use of dynamic stochastic general equilibrium models in analyzing economic policies by central banks and eliminating the flaws of these models, on the other hand, necessitate designing a dynamic stochastic general equilibrium model with dual labor market based on Iran's economy. To do so, the current study divides labor market into formal and informal sectors. In addition, it classifies firms in formal and informal ones regarding the type of the production function and labor. The annual data used in the model are collected from the Central Bank and the Statistical Center of Iran during 1974-2010. After calibrating and solving the model with numerical method, the shock effects of total factors productivity, government expenditure, oil revenue, and money growth on real variables of the model have been analyzed with and without nominal wage rigidity. The results of the study suggest that the informal sector of the labor market in different business cycles acts as a buffer with countercyclical shift. The money is not neutral in the short run due to lack of rigidity in a model of monopolistic competition, so money supply affects real variables of economy.

Volume 14, Issue 3 (5-2012)
Abstract

The objective of this study was to determine the inbreeding depression on growth traits in Moghani sheep. Pedigree information of 8836 animals collected during the years of 1987 to 2006 by Moghani Breed Center in Jafar Abad Moghan, were used for analysis. The base population year was 1988. Analysis of the records was performed by ASReml software. Inbreeding depression was estimated as the regression of performance on the individual inbreeding coefficients via fitting an animal model. The mean inbreeding for all animals, females and males, were 0.500, 0.515 and 0.484 %, respectively. Totally, 24.22 % of all the animals were inbred. The mean of inbreeding for inbreed animals was 2.062 %. The rate of increased inbreeding per year for all animals was 0.05%. The inbreeding depression for body weight traits at birth, 3, 6, 9 and 12 months of age was , respectively, -0.007, - 0.291, - 0.026, -0.018 and -0.041 kg, per 1% increase in individual coefficient.

Volume 14, Issue 4 (7-2014)
Abstract

In this paper, a real time simulator of the engine-generator for a series hybrid electric bus is designed which can be used for hardware in the loop testing of the hybrid bus control unit. As an important step for designing a hardware in the loop simulator, messages that the engine and generator receive from the vehicle control unit are identified. Design of the simulator is based on these received messages and dynamic behavior of the components. Since the engine and generator receive speed or torque commands from the vehicle control unit, two PID controllers are designed to bring the engine or generator to the desired speed. By applying appropriate inputs, different modes of operation of the diesel-generator is simulated including the soft start process and steady state operation. For a simulator, the ability to interface with a real hardware requires a real time simulation. To do so, the design process is implemented in LabVIEW environment and results show that the designed simulator gives responses close to real test results and it is suitable for developing the hybrid vehicle control unit.

Volume 14, Issue 12 (3-2015)
Abstract

Due to the complexity in the control system of hybrid vehicles, the electronic control units should go through extensive testing before getting installed in a prototype vehicle. In the first stages of the development process, Hardware-in-the-Loop (HiL) simulation can not be performed because the hardware components of the vehicle are not yet available. In this case, Model-in-the-loop (MiL) simulation is used which couples the designed control software with an environment simulation with no need for a special hardware. In this paper, the MiL simulation is introduced for verification of the vehicle control software in a series hybrid electric bus. To do so, considering the dynamic behavior of various components of the vehicle, a simulator of the hybrid bus is designed by going through with the input/outputs of the vehicle control software. Using the designed test bench, the user can act as a real driver and experience different driving regimes and analyze the control software commands. In the designed simulator, all subsystems are simulated separately in LabVIEW environment and real-time simulation is achieved with an acceptable error. Therefore, it can be used in a HiL test bench for testing each of the vehicle components. The designed simulation model has been validated using real test results. Using that, results show that all control functions in the vehicle control software can be tested and verified with no cost and in the shortest possible time.

Volume 16, Issue 1 (8-2013)
Abstract

Objective: In recent decades, β-glucans have been used as important complementary and alternative medicines for numerous immunocompromised individuals and those with end stage of cancer terminal. The most active form of β-glucans is β(1,3)D-glucan and its  most common source is cell wall of Candida albicans. Recently it has been introduced as a nano particle design to be used as a carrier for drug delivery. The current study researches a rapid method for the extraction of β(1,3)D-glucans. Methods: The present study was conducted atTarbiatModaresMedicalUniversity in 2012. Candida solubilized β-glucans were obtained by oxidation of the cell wall with sodium hypochlorite and sodium hydroxide. The particle part could be solubilized by treatment with dimethylsulfoxide (DMSO) and zymolyase digestion to extract β(1,3)D-glucan. The soluble fractions were lyophilized. We performed the Callose test to verify the presence of β(1,3)D-glucans. Solubilized fractions were dissolved in D2O and 1H-NMR spectra were measured. Results: The soluble β(1,3)D-glucan fraction which was derived from 1 g of dried Candida albicans germ tube weighed 190 mg. β(1,3)D-glucan was verified by the Callose test and 1H-NMR test compared with Curdlan (standard). 1H-NMR spectra verified the existence of β(1,3)D-glucan in the final product. Conclusion: In the present study, extraction of β(1,3)D-glucan by oxidation of the cell wall using sodium hypochlorite yielded more pure β(1,3)D-glucans in comparison with other extraction methods. Thus it might represent a rapid method of extraction.

Volume 19, Issue 11 (November 2019)
Abstract

In this study, a hybrid system of fuel cell/gas turbine was designed and simulated with the aim of coupling with desalination systems. This system was analyzed from the viewpoints of the first and second law of thermodynamics. A parametric analysis was also performed to the determination of the system optimal performance. The studied parameters are fuel utilization factor, compressor pressure ratio, pre-reforming percentage, and the steam to carbon ratio. The results show that for the design parameters, the net power is 1215kW, the overall efficiency is 81.65% and the exergy efficiency is 60.7%. Also, by analyzing the rate of exergy destruction, it has been determined that the stack of fuel cells, combustion chamber, and pre-reforming have the most part in the destruction of exergy. Parametric analysis results show that increases in pressure, pre-reforming percentage, and fuel utilization factor have a positive effect on the system performance to a certain extent and the suitable ranges of the fuel utilization factor are from 0.8 to 0.85. On the other hand, by analyzing the effect of pressure and temperature on the system, it is determined that the temperature of the fuel cell cannot be constant. It was also shown that the efficiency of the system decreases with increasing steam to carbon ratio.


Volume 23, Issue 7 (July 2023)
Abstract

Today, various military, aerospace, automotive, etc. industries need materials with a high strength-to-weight ratio. The use of metal-based composite materials, especially aluminum-based composites, has increased greatly. Machining is needed to achieve high dimensional accuracy in products made with aluminum-based composites. Due to the presence of reinforcing material such as silicon carbide, machining of this type of material is difficult. Therefore, it is important to study the parameters affecting the machining of aluminum-based composites. In this study, the effect of spindle speed, feed rate, depth of cut and percentage of reinforcing particles were discussed using experimental and statistical test methods. The responses of surface roughness and material removal rate were investigated. The behavior of the input parameters on the responses of the process has been carefully investigated quantitatively and qualitatively. Answers have also been optimized. According to the obtained results, the spindle speed has the greatest effect on the surface roughness. Also, feed rate 33%, spindle speed 28%, depth of cut 26% and the percentage of reinforcing particles 13% have an effect on the chipping rate.

Volume 23, Issue 8 (August 2023)
Abstract

Advances in many engineering fields depend on materials with appropriate properties. The use of metal-matrix composites is rapidly growing as a suitable alternative to conventional materials due to their strength-to-weight ratio, resistance to wear and creep, etc. Machining of metal-based composites is a difficult task due to the presence of very abrasive reinforcing particles in its based metal. Therefore, it is necessary to investigate the factors affecting these materials. In this research, a methodical study has been conducted to investigate the effect of the parameters of spindle  speed, feed rate, depth of cut and the percentage of reinforcing particles on the behavior of cutting force and tool wear using experimental design methods, modeling and statistical sensitivity analysis methods. . Detailed analysis of behaviors has been done by providing statistical regression equations and optimization by Deringer's method and E-Fast-Sensitivity Analysis. According to the obtained results, the cutting depth had the greatest effect on the machining force. Also, cutting speed with 77%, advance rate with 9% percent and cutting depth and weight percent of reinforcing particles with 7% percent are other parameters affecting tool wear in the milling process of this composite.
Seyyed Taghi Andy, Arsalan Golfam, Ferdows Aghagolzadeh, Mojtaba Monhshizadeh,
Volume 29, Issue 1 (1-2022)
Abstract

Compounding is one of the most common and also very productive word formation processes among languages in the world. Because of its productivity and high frequency, it has precisely been studied by many Iranian and non-Iranian linguists. However, this productive process has not yet been studied in Mazandarani. In the present study, first Mazandarani compound words taken from Tabari dictionary, have been analysed in the form of a table and based on the criteria such as syntactic category, semantic classification of compound types (endocentric, exocentric and dvandva), the position of head and being verbal or nonverbal. By taking into consideration the above mentioned criteria and based on three fundamental concepts, namely, head, dependent (non-head) and feature percolation, the resulting compounds have been analysed separately. At the end of the article, after studying and evaluating the hypotheses, appropriate explanations have been presented. The high frequency of “N+ N → compound noun construction” refers to their predictability in meaning compared to other constructions. It means that there is a direct relationship between high frequency of a word formation process and its semantic predictability. Also, the reason why endocentric compounds are more frequent than others is due to the fact that both constituents of the compound are used in their original meanings. Hence, endocentric compounds are unmarked elements and are easier to learn in the process of language learning. The above mentioned findings are in line with markedness theory. That is why the frequency of occurrence of unmarked elements is higher than marked ones which is related to language universals.

Page 1 from 1