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Showing 6 results for محمودیان


Volume 5, Issue 1 (7-2021)
Abstract

Abstract:
Research subject: Leaching and recovery parameters controlling the releasing of selenium from Sar-Cheshmeh copper anode slimes are studied and determined.
Research approach: Copper anode slimes is produced during the production of cathodic copper at the bottom of electrolyte cells, which is composed of insoluble anode components in the electrolyte. The copper anode slimes are made up of those components of the anodes, which are not soluble in the electrolyte. They contain varying quantities of precious metals like gold, silver, selenium and tellurium, and other precious metals in the anodic copper. They are being extracted as a by-product in the copper production process. Due to the fact that the main source of selenium is sulfur deposits such as copper and nickel. Copper anodic slimes is currently the only source of selenium in the world. In this study, the extraction of selenium from anodic copper slimes has been feasible. To do this, acid leaching has been used. Copper anodic sludge is the raw material for the production of more than 90% of the world's selenium and is the main source of selenium production.[1-3]
Main result: In this paper, the effect of operational parameters such as acid concentration, temperature, process time and liquid to solid ratio on selenium recovery through copper slimes leaching was investigated. The optimum conditions of batch leaching For maximum selenium extraction from anodic copper slimes are attained at 3 mol L-1 of HNO3 concentration, 0.01 (W/V) solid to liquid ratio for 60 min contact time at 70 º­C. Under the optimized conditions, the selenium leaching efficiency was 99%. The thermodynamic data showed positive values of both ΔH and ΔS which indicates that the leaching process is indeed endothermic and random while the obtained negative values of ΔG show that selenium dissolution process is spontaneous in nature.

Volume 6, Issue 4 (No.4 (Tome 25), (Articles in Persian) 2015)
Abstract

Although syllable is not a meaningful unit of language, it has major functional roles in language. One of the most important functional roles of syllable is the formation and organization of language’s phonetic system. Any language has its specific syllable construct (patterns), and specific restrictions for the combination and use of sounds in the syllable level. In addition, various languages usually tend to keep their syllable rules; so, syllable patterns usually are not loaned by languages. Therefore, it can be said that part of differences in phonetic systems in various languages are caused by differences in their syllable structure. On the other hand, due to its main function (formation and organization of language’ phonetic system), syllable is directly associated with the learning of language’s phonetic system. The present article deals with comparison of the common syllable patterns in Russian and Persian languages. The results show that the patterns of the Russian syllable are more diverse than that of Persian. Most important differences that are often problematic for Iranian learners are the heavy consonant cluster in the onset of Russian words and syllables, as well as the frequency of multi-syllabic words in Russian language.  

Volume 10, Issue 6 (Vol. 10, No. 6 (Tome 54), (Articles in Persian) 2019)
Abstract

The present paper seeks to analyze the main term-formation methods in Persiand and Russian Languages Special languages and their linguistics specification (morphological, syntactic, word formation and etc.) are one of the most research subjects in modern terminology. Recently , among these linguistics specifications, researches on  term formation are becoming necessary due to their main role in terminology systematization.
On the other hand, with the increase of inter-linguistic interactions in the specialized fields, the comparative aspects of the aforementioned researches have made a major contribution to the research in this field. It is evident that for such research, a general reference system of the classification of tools and methods of word formation is necessary.
This paper aims to present a common system for different types of term formation in Persian and Russian languages. This paper answer to this question: to what extent term-making tools and methods are overlapping in these two languages, and could reach into a comprehensive classification of both Persian and Russian languages?
To This end, The authors first studied all present kind of term-formation methods and tools in both Persian and Russian languages. The result showed, in the first section, the relative affinities term-formation methods and tools for the Russian and Persian languages. Next, according to classification cited in Russian sources and focusing on the linguistic nature of the new term-formation method, the term – formation methods were classified into five general categories of morphological, syntactic, semantic, borrowing, and abbreviations making.
 
Morphological method focuses on morpheme (generally affixes) for new word; syntactic method leads to phrase-formation as an term; in semantic method usually, words of general language are transformed to terms using metonymic or metaphoric tools; in borrowing, words incorporated into one language from other languages and in abbreviations making – as a word formation method, words divided to a unit such as phoneme.
 

 
 

Volume 15, Issue 1 (3-2015)
Abstract

In the present paper, a new combined technique consist of experimental results and numerical solution for determination of elastic constants of thin and thick orthotropic plates with various stacking sequences; and also isotropic plates under different boundary conditions is proposed. This new proposed technique makes use of vibrational test data, corresponding numerical solution and optimization methods. The vibration test data consists of a set of eigen frequencies that are obtained from transverse vibration test of the plate. The numerical solution is based on a finite element method using a commercial program. Material constants of the plate are determined by using of the inverse method and a particle swarm optimization algorithm in MATLAB software. The error function is based on the sum of square difference between experimental data and numerical data of eigen frequencies solution. The validation, performance and ability of the proposed technique in this paper are discussed using experimental and numerical data available in the literature. The higher accuracy of results that obtained by the present method in comparison with other methods proved the validity and capability f the new proposed method.

Volume 20, Issue 145 (March 2024)
Abstract

Yogurt drink is one of the fermented dairy products. Probiotic yogurt drink has special health properties due to the presence of probiotics. Also, adding herbal-medicinal plants including chavil to this product can make it more attractive. However, the shelf life of probiotic bacteria in yogurt drink is not very long. This research was therefore carried out to increase the shelf life of Lactobacillus rhamnosus in yogurt drink by nanoencapsulation technique with Persian gum and whey protein isolate. Particle size and SEM was used for determination nanoencapsulated bacteria (bead) characteristics. In this regard, three samples of yogurt drink containing free Lactobacillus rhamnosus, its bead and the control were produced. Some characteristics including pH, acidity, sensory including color, taste, consistency and overall acceptability of yogurt drink were measured as well as the shelf life of probiotic bacteria under gastrointestinal conditions and storage in the refrigerator. The results showed that the beads had a size from 246.98 to 356.2 nm. The efficiency of nanoencapsulation was 87.2%, and the SEM images showed that the bacteria were covered well. At the end of the storage time, the decrease in pH (3.41) and increase in acidity (97.3 °D) of the sample containing beads was highest. The counting of free and beads also showed that the shelf life of bead was greater than free bacteria in yogurt drink. In the 21st day of storage, the product was eligible for probiotics. Moreover, the bead survival in simulation gasterointestinal condition was 3.33 log cfu/ml. The evaluation of the sensory parameters also showed that the sample containing bead had the lowest score among the panellist in all the sensory components except the texture. In conclusion, it can be stated that the yogurt drink containing the bead sample can qualify as a probiotic product during 21 days of storage time.
 

Volume 24, Issue 2 (summer 2024)
Abstract

Introduction
The occurrence of various shocks affects economic variables and change their course over time. Knowing the effecst of such shocks on economic variables is necessary for proper policy making in the economy. Therefore, many researches are conducted in this field in the world. Policy-making without recognizing these effects can result into tremendous challenges. One of the most effective shocks in the Iranian economy is the sanctions, especially the nuclear ones, which have had extensive effects on the behavior of brokers and consequently on the country's economic variables.
Economic sanctions cause a change in the exchange rate by creating a chaotic atmosphere and confusion in the economy, followed by a change in the supply and demand of housing. Therefore, the purpose of this research is to investigate the effect of economic sanctions on the supply and demand of housing through the exchange rate channel. For this purpose, provincial seasonal data for the period of 2011-2021 have been used and Seemingly Unrelated Regression (SUR) model has been used to analyze the data.
Methodology
Different methods can be used to estimate the model of the equations of this study, such as single equation methods or methods of solving simultaneous equations, whose estimates are different. The most common methods of solving simultaneous equations are the two-stage and three-stage least squares regression methods, as well as Seemingly Unrelated Regression, which is used when there is a relationship between the error part of the equations or there is a simultaneous correlation. The method discussed in this research is Seemingly Unrelated Regression (SUR) model or Seemingly Unrelated Regression Equations (SURE), which was proposed in 1962 in econometrics.
Findings
The findings show that provincial gross domestic product, housing prices, and inflation have a positive effect on demand. The variables of stock market index, exchange rate and sanctions have had a negative effect on housing demand. On the supply side, housing price variables, the number of building permits issued, and inflation have a positive effect on the housing supply, while the exchange rate, sanctions, and the price of construction materials have a negative effect on the housing supply. Imports and embargoes have increased the exchange rate and exports have decreased the exchange rate. On this basis, the embargo has both a direct effect and an indirect effect through the exchange rate on the reduction of housing supply and demand.
Discussion and Conclusion
The estimation results for the first equation show that the variables are significant. It can also be said that provincial GDP, housing prices and general price level index have a positive effect on housing demand and with the increase of these variables, housing demand increases. According to the findings of the research and the analysis of the available data, the inverse relationship between the stock market index, the sanctions index and the exchange rate with housing demand is confirmed. So, with the growth of the stock market index, sanctions index and exchange rate, the demand for housing decreases.
In the preliminary results, the estimate for the second equation of the average effect of labor wages as a part of the production cost was not significant. But in estimates, the effect of the price of construction materials is significant. This variable was removed from the model. It can be said that one of the reasons for the non-significance of the wage variable is its low relative growth compared to the growth of housing prices and the growth of construction materials. On the other hand, the share of wages in housing construction costs is much lower than the costs of materials and other costs. This causes the wage rate in Iran to be less effective in housing supply. It can also be said that an increase in the provincial GDP, housing prices and the number of building permits issued increases housing supply.
The results of the third equation show that exports, imports, sanctions index, liquidity volume and provincial GDP explain 99% of exchange rate changes. It is worth mentioning that any increase in exports and sanctions index increases the exchange rate, but with the increase in imports, the exchange rate decreases, which shows the negative relationship between the exchange rate and imports. Since the exchange rate increases under the influence of the sanctions and the exchange rate has a negative effect on the housing demand, it can be said that sanctions have a direct effect on the economic activities of supply and demand due to the disruption of security, certainty and economic stability. Housing has an effect on the supply and demand of housing due to the change in the exchange rate


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