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Showing 23 results for Etemadi


Volume 8, Issue 3 (3-2019)
Abstract

Today, due to the ever-increasing competition between organizations and uncertain environments that have been created by many changes in customer needs, using an efficient supply chain can be considered as a competitive advantage for any organization. In this regard, one solution is lean approach. Lean approach helps to eliminate waste in the supply chain. On the other hand, based on the state of Iran and the abundance of oil and gas resources, the implementation of lean approach in the supply chain of the organizations operating in this field is very important.
In order to conduct this study that has been carried out in one of the largest companies operating in the offshore sector and the aim of this research is to provide a lean supply chain model in offshore oil and gas industry and accordingly, executive solutions can be presented.  First, by reviewing the literature and opinion poll at the experts, the 11 factors that lead to lean supply chain were identified. Then, using fuzzy analytical heararchy process and interpretive structural modeling approach, the research model was developed and based on it, the factor: “leadership and management”, “information sharing”, ‘financing” and “supplier contact” identified as the most influential and “minimizing the delivery time” was identified as the most influential factor. In the next step, the model was validated in quantitative and statistical analyzes as well as qualitative. Finally, some suggestions were made to achieve lean procurement process in the offshore sector of the oil and gas industry.
 

Volume 8, Issue 33 (9-2004)
Abstract

Calculating the cost of product precisely and presenting reliable information and reports for economic decision making are the objectives of cost accounting systems. But, the independent auditors reports reveal that most of the manufacturing companies, especially state companies, do not possess suitable methods for cost accounting of products. To identify the insuficiencies of cost accounting systems of these companies, two companies, involved in steel industry were selected and operation process as well as working methods of their different part were examined. The results show that the cost accounting system of the selected companies, compared to a suitable accounting system is very in appropriate. The reasons of its inappropriateness are absence of proper procedures for production cercufation, absence of accounts related to production process, absence of correct information a bout the capacity of production lines, inability to recognize costs behavior, not using proper bases for over head allocations, not using budget mechanism related to list of the bills, not colwlating and registering variances and not preparing reliable managerial reports at certain periods of time.

Volume 9, Issue 1 (Winter 2018)
Abstract

Aims: Heavy metals are one of the most important pollutants in earth and water environments due to long-term durability. The aim of this study was to isolate phosphate solubilizing bacteria from metal waste, investigate the amount of resistance, remove the metal by it and the effect of phosphatase on removal of metals.
Materials & Methods: In this experimental study, the isolation of phosphate solubilizing bacteria and detection of isolates were carried out, using biochemical and molecular tests. The phosphatase was measured by colorimetric method, the resistance of the separated to the metals with the minimum inhibitory concentration (MIC50), minimum bactericidal concentration (MBC) and the rate of removal of metals by atomic absorption was measured. The surface changes of the exposed metal cells were investigated by Fourier Transform Infrared Spectroscopy (FTIR) and the effect of phosphatase on metal removal. Data analysis was done with Duncan's test, using Excel 2013 and SPSS 20 software.
Findings: Serratia proteamaculans was identified as producer of the acid phosphatase. The highest MIC and MBC were obtained for Nickel (Ni) and Lead (Pb), respectively. The most metal removal was for Pb. MIC50 of Chrome and Cadmium were obtained less than 0.1mM and 1mM, and their removal percentage by the isolate were 18% and 48%, respectively. According to the FTIR, 988.339cm-1 wavelength was observed in the cells treated by 5mM Pb that is related to the Pb3(PO4)2. The isolate showed the highest resistance and removal of Pb. The mechanism of Ni removal was associated to the cell surface, while Pb was removed by both of the cells and supernatant containing phosphatase.
Conclusion: Serratia proteamaculans is the phosphate solubilizing bacterium in metal waste. This bacterium produces an enzyme called phosphatase, which is a cause of lead removal.

Volume 9, Issue 4 (Fall 2018)
Abstract

Aims: Alkaline protease is one of the most important groups of industrial enzymes with many applications. The aim of this study was to determine the physicochemical parameters affecting the production of alkaline protease enzyme produced by Bacillus pseudofirmus MSB22 by one-factor-at-a-time (OFAT) method and optimize the production of this enzyme by the response surface methodology (RSM) in the form of a rotatable central composite design.
Materials and Methods: In the present experimental study, the isolation of microorganism producing alkaline protease from wastewater from sausage and lunch meat factories in Isfahan was carried out. The morphological and biochemical characteristics of the strain were performed according to the Bergey's book and amplification of 16S rRNA gene sequences. Detection of metalloproteinase gene and alkaline serine protease was done by polymerase chain reaction (PCR) reaction and enzyme activity measurement was performed by Folin reagent. Screening of variables effective in enzyme production was done, using one-factor-at-a-time method and optimization was performed by response surface methodology. MEGA 6 software was used for phylogenetic analyses. To analyze the data, the Design Expert 7 software and the one-way analysis of variance were used.
Findings: The maximum protease production, which was 1.85 times higher than that of OFAT method and 3.45 times higher than unoptimized conditions was obtained, using 1% w/v xylose, 3% w/v beef extract, 4% v/v inoculation size, pH 10, and 30°C. The established quadratic model had a great ability to predict responses to new observations due to a high value of the predicted determination coefficient.
Conclusion: OFAT and RSM strategies are useful screening and optimization methods, respectively and sub I and sub II genes (alkaline serine protease genes) are detected in Bacillus pseudofirmus MSB22.
 


Volume 10, Issue 2 (10-2020)
Abstract

In the organizational world, leaders or executives are highly influential, and managerial and leadership positions are one of the most important organizational professions. This subject is more important in public organizations due to key role of them in society. In this survey, researchers seek to provide appropriate leadership model for public organizations. Reviewing this subject, “lean leadership", which traditionally used in the industrial environment, can be considered as the basis for extracting the model of lean leadership in Public organizations. For this purpose, 23 in-depth, semi-structured interviews were conducted with the academics and executive (or simultaneous) and experts of the subject, by using targeted sampling method. Based on the key coding strategy, the open, axial, and selective coding steps were implemented, and by the effective and efficient use of Software (MAXQDA.PRO.2018.1), the axial category "government requirements”, “authenticity"  ,"strategies", "external influences" "intra-organizational actions" were extracted, which led to the consequences of this exploratory model in the context of the category of “lean leadership”. The two key findings of the research process include "descriptive exploratory model of lean leadership in Public organizations" and "extracting theoretical theorems”.

Volume 11, Issue 2 (Spring 2020)
Abstract

The combustion of fossil fuels containing sulfur results in the release of sulfur dioxide into the atmosphere and environmental pollution. Hence, the researchers focused on the biological desulfurization method. Dibenzothiophene is used as the model molecule to study the ability of the desulfurization of microorganisms. The most suitable sources of carbon, nitrogen and sulfur concentration optimized by response surface method to obtain the highest cell growth and biological desulfurization activity. The performance of iron nanoparticles on the growth and biodesulfurization activity of thermophilic bacterium Bacillus thermoamylovorans strain EAMYO was investigated. Characterization of starch-modified iron nanoparticles was performed by TEM, SEM. The images of TEM and SEM of starch / Iron nanoparticles showed that the Fe3O4 and Fe0 nanoparticles were 20 and 30 nm, respectively. The investigating the growth of microorganism in the presence of iron nanoparticles showed that these nanoparticles not only did not have a toxic effect on microorganism growth, but also increased the growth of microorganism in 96 h (OD 660 = 1.864, 1.896 respectively in the presence of nanoparticles Fe0 and Fe3O4), while the highest rate of growth in the absence of nanoparticles in 96 h (OD660 = 1.51). Also, the activity of desulfurization in the presence of starch/Fe0 nanoparticles and starch/Fe3O4 / starch increased by 26.52% and 10.75%, respectively, compared to the cells without the coating of iron nanoparticles.
 

Volume 12, Issue 2 (1-2022)
Abstract

Background: Carotenoids are biological antioxidants and play important roles in protecting the body from diseases and aging. Canthaxanthin is one of the most widely used carotenoids in the industry and medicine. This study aimed to investigate the biological properties of canthaxanthin pigment as well as its production optimization in a low-cost medium using a radioresistant microbial strain named Dietzia maris.
Materials and methods: Bacterial carotenoids were extracted and its antibacterial, anti-tumor, and cytotoxicity properties were investigated. Then, the effect of Krebs intermediates and pH on the production of pigment and microbial biomass in the whey medium was investigated using the response surface methodology.
Results: Maximum pigment production was found to be 92/54 mg/l in whey culture medium at pH 8 and in the presence of 12.5 mM of each of citrate, glutamate, malate, and succinate by the response surface method. The pigment did not show any cytotoxic effect on Hela, HFB, and MCF-7 cell lines. Besides, the pigment did not have any antibacterial properties.
Conclusion: Radioresistant microbial strains are better candidates for microbial pigment production due to their stability and high antioxidant activity. In this study, a whey culture medium was used to reduce the production cost of canthaxanthin. The addition of Krebs intermediaries in the fermentation medium increased the pigment production by Dietzia maris significantly.

Volume 12, Issue 3 (9-2009)
Abstract

Objective: With consideration of lethal effects of aflatoxins specially B1 on human health. Estimation of aflatoxin-albumin adduct, as an important marker of aflatoxin exposure, seems essential. The aim of this study is optimization of HPLC-fluorescence method for measurement of this important marker in blood serum. Materials and Methods: In this study, blood serum of three groups of rats as A) positive controls (treated with AFB1), B) negative controls (without treatment) and standard rats (treated with radiolabeled AFB1) were used. After albumin isolation using ammunium sulphate and acetic acid, purity of albumin was tested by SDS-PAGE electrophoresis and albumin concentration was quantified by bradford method. Then albumin was hydrolysed by pronase and aflatoxin bound to albumin was released as aflatoxin-lysine. Pronase was precipitated and albumin was digested by aceton in cold, the volume of supernatant was reduced by freeze-drier and injected into HPLC system. Aflatoxin was quantified in comparison to standard rats samples. Results: The purity of this isolated albumin was confirmed by SDS-PAGE electrophoresis. Albumin concentration in positive, negative and standard samples were 10, 13 and 12.5 mg/ml, respectively. Detection limit (20 pg/mg Alb) for measurement of aflatoxin was determined by HPLC method, specificity and sensitivity of method were 92% and 100% respectively. The mean concentration of AF-Alb adducts in serum of positive control rats was 10 ng/mg Alb and the reproducibility of the method after several repeat was very good. Conclusion: In this study, for AF-Alb adduct quantification by HPLC method, mobile phase, percentage of solvents and run time were changed and the affinity chromatography before HPLC, was deleted. Therefor HPLC- fluorescence which is a precise and specific method, and since it is fast, highly reproducible and cost effective, also with improvement made, could easily be used for the quantification of this important marker in serum.

Volume 13, Issue 1 (6-2023)
Abstract

A new trend in human resources, especially in the last decade, is the issue of digital talent. This event is certainly influenced by the evolution of the digital economy and the effects that digital technologies such as artificial intelligence have left on the business environment. As little research has been done on digital talent, there is still insufficient knowledge on what digital talent is and what to do about it. Therefore, this study, as one of the earliest studies in the field of digital talent, has investigated this issue in the banking industry. The research approach in this study is grounded theory. Data were obtained through interviews. At the end of the research, the extraction of 326 common first-order open source codes (out of 434 first-order codes), 72 second-order open source codes (resulting from common open source coding), 24 axial categories and 5 selective categories including: Philosophical and organizational orientations of digital business; Cognitive mapping of digital talent based on digitization initiatives; Recognize situational patterns and perspectives with the aim of understanding environmental events; Orientations of strategic actions in the development of DTs; And improved the level of individual and organizational performance.


Volume 13, Issue 2 (4-2010)
Abstract

Objective: Saffron is the dried stigmas of Crocus sativus L. which has various therapeutic properties in addition to its use as a spice. More than 80% of the world present production of saffron which is about 190 tons is produced in Iran. To compare the quality of saffron' from different parts of the world, researcher used one sample from each country. Since cultivation of saffron is done in different geographical areas of Iran, it seems that the results of these studies, using only one sample of Iranian saffron, are not consistent with the scientific and statistical rules. More over the results of therapeutical studies using saffron extracts from different sources with different concentrations of effective elements would not give reproducible results. As an affirmative reason, here we compared the saffron’s important components, crocin, picrocrocin and safranal, from different packages produced by some companies. Materials and Methods: Five certified saffron packages, prepared by different companies named: Ehteshamiyeh, Tarvand, Abbaszadeh, Sabagh and Novin-Saffron were analyzed using HPLC with an UV/Vis detector. To avoid the conflict of inerest, these samples were randomly labeled as 1 to 5. Results: Results indicated that all of the samples contained these ingredients at the standard levels, but the highest level of crocin as a carotenoid was seen in the sample 3, and sample 1 and 2 contained the highest concentrations of monoterpene aldehydes, picrocrocin and safranal, respectively. Conclusion: According to the obtained results and the vast area under the saffron cultivation with various climates, it is confirmed that one sample of saffron is not a measure of all of the Iranian saffron. Our research is continuing.
Hossein Etemadi, Bagher Shams Zadeh,
Volume 14, Issue 1 (2-2007)
Abstract

During the past two decades business and manufacturing have observed significant and radical changes. Companies have used automation in the manufacturing, in order to improve quality and competency. It was expected that along with these changes, management accounting systems, which focus on monitoring and analyzing management decisions, should adapt with and encourage the changes. Many authors have claimed that management accounting systems have not helped the suitable business and manufacturing strategies in the new environment. Some even claim that it has hindered investing in advanced manufacturing technology and productivity. This research, by analyzing information collected from 101 Iranian business units from various industries and manufacturing settings, investigates justification basis for capital investment in advanced manufacturing technology. The study demonstrates that there is more correlation between qualitative factors such as; manufacturing capabilities, improved product quality and, competition position with investment justification than quantitative bases such as; accounting rate of return (ARR), internal rate of return (IRR) and, net present value (NPV).

Volume 14, Issue 13 (First Special Issue 2015)
Abstract

This paper presented a theoretical model to investigate steady plastic shock wave on FCC metals. The method included shear flow stress according to effective parameters and based on microstructure and dynamics of dislocation method. The aim of this paper was to achieve final relation between shear stress and plastic stretch with presenting constitutive equations for shock loading. Then, Shear flow stress to effective plastic strain was plotted with solving final relation between shear flow stress and plastic stretch. Presented constitutive equations were based on loading under one dimensional strain and were validated just for shock loadings. The main innovation of this investigation included using from energy constitutive law with considering entropy generation rate. Entropy generation rate expressed as dislocation generation, dislocation annihilation and dislocation glide. Also, the effect of shock velocity, total stretch and input stress according to plastic stretch were investigated. Furthermore, shock structure was investigated according to different input stresses. Maximum input stress was 25 GPa. Relations and diagrams were verified with published experimental works on Al 6061 alloy. Good agreement was found between presented model and experimental works.

Volume 15, Issue 5 (9-2013)
Abstract

 The present study evaluated the effect of packaging (air, vacuum) with or without addition of sodium acetate (2% W/V) on shelf-life extension of rainbow trout (Oncorhynchus mykiss) under refrigeration, for a period of 18 days. Four different treatments were tested: CAP: control air pack; SAAP: sodium acetate treated aerobic packaging; VP: vacuum packaging in the absence of sodium acetate; and SAVP, sodium acetate under VP. Trimethylamine nitrogen (TMA-N), free fatty acids (FFA) and peroxide values (PV) of SAVP samples were lower compared to the other treatments during the entire refrigerated storage period. In the present study, the thiobarbituric acid (TBA) level showed fluctuations during storage indicating that TBA values may not reveal the actual rate of lipid oxidation. Total viable counts for fresh rainbow trout stored aerobically exceeded 7 log CFU g-1 after 10-11 days, while treatments SAAP and VP reached the same value on days 12 and 16, respectively. In contrast, SAVP samples did not reach this value throughout the 18-day. Psychrotrophic counts of SAVP samples were significantly (P< 0.05) lower compared to the control samples during storage period. As regards sensory evaluation, shelf-life of trout was longest for SAVP (15-16 days), followed by VP (12-13 days), SAAP (9-10 days), and CAP samples (6-7 days). The results indicated that the combined effect of vacuum packaging and sodium acetate on fish samples preserved their good quality characteristics and extended the shelf-life of the treated samples during refrigerated storage, as supported by the results of microbiological, chemical, and sensory evaluation analyses.

Volume 17, Issue 1 (3-2017)
Abstract

In this paper, the fluid- solid interaction in an electrostatic microbeam by using three- dimensional aerodynamic theory has been studied. Modified couple stress theory is used to model the elasticity depends on the size of the microbeam. The proposed model can be used as a mass micro- sensor. To analyze the dynamic behavior of the microbeam a DC voltage applied to the system and then by applying an AC voltage dynamic characteristics of the system around static deformed condition is analyzed. Because of non-linear nature of the governing equations to solve them reduced order model based on Galerkin is used. Results have shown that considering the couple stress and also increase the size of the length characteristic parameter reduces the size of the fluid pressure differential created between the two sides of the microbeam. However, according to the three- dimensional aerodynamic theory for fluid-solid interaction, change of the pressure difference created does not lead to creation difference in predicting the size of the added mass between the classical and modified couple stress theories. In another part of the results has been shown that the presence of added mass to what extent can makes changes in the frequency response curves drawn for the system. Also applied the couple stress theory and increase the size of the length characteristic parameter makes the system more rigid and consequently reduce the amplitude of the vibration and frequency response curves shift to the right.

Volume 17, Issue 3 (5-2015)
Abstract

Olive is a perennial evergreen tree which has good adaptability to poor environmental conditions such as salt and drought resistance. In recent years, there is a tendency to plant olive trees in green spaces. Therefore, this study was carried out to evaluate 15 olive cultivars regarding growth habit, form, and texture to recommend for landscape. Six-year-old trees of 15 olive cultivars, which had been planted in Isfahan University of Technology (2000), were used in randomized block design with 3 replications and some of their vegetative characters were measured. A cluster analysis was done using seven factors effective on tree texture, which divided cultivars into 3 groups and a separate genotype. Also, another cluster analysis done on the seven factors effective on tree form classified olive cultivars in 3 groups. In short, Manzanilla, Spain, and Amphisis cultivars performed wide oval form and fine-medium coarse texture, so they could be used as background tree, screen, and group planting in green spaces. Roughani, Mishen, Valanolia, Gorgan, Kroneiki, Zard, and Sevillana cultivars showed round form and medium texture which could be used as specimen tree to plant in lawn. Rashid cultivar with long height, long oval form, and coarse texture is suitable as accent, screen, and frame plant.

Volume 17, Issue 4 (6-2017)
Abstract

In this paper, the behavior of a new type of auxetic composite (composite with negative Poisson’s ratio) consisted of polyester fibers and ABS tubes as reinforcement as well as polyurethane foam as matrix was investigated by finite element method. Furthermore, the effect of negative Poisson’s ratio and mechanical properties of auxetic composite under quasi-static pressure were analyzed and the results were compared with the published experimental works. Good agreements were found between the results. Considering stress-strain diagram, it is concluded that this type of composite can operate as a damping material due to the specific properties such as high shear strength, indentation strength toughness. So, the foresaid properties make them a great choice with high potential application in various industries. Also, the ways to get the effective parameters to achieve more negative Poisson’s ratio were investigated. The parameters include the foam density as well as material, diameter and distances between ABS tubes. The results show that with decreasing foam density and decreasing distances between ABS tubes, the negative Poisson’s ratio increases at first to reach the critical value and then decreases.

Volume 17, Issue 12 (2-2018)
Abstract

The main purpose of using scaffolds replacement tissues of the body. The most important part is to choose the type and steel scaffolding so that eventually will replace the damaged tissue. One of the mechanisms proposed to reshape the bone is based on its piezoelectric properties. It seems that the use of piezoelectric materials is an option for use in the body, is a unique privilege. Therefore, the ceramic barium titanate (BaTiO3) having good piezoelectric properties, Curie temperature of about 125˚C and laboratory observations that non-toxic in the body, as a candidate to replace and simulate the performance of bone tissue, has been proposed. In this study, the design and produce of barium titanate piezoelectric ceramic as a bone scaffold with foam casting method and become coated with gelatinous and nanostructured HA composite for bone tissue engineering. Then test its properties by infrared spectroscopy, X-ray diffraction, scanning electron microscopy and mechanical properties were studied. In the end, it was concluded that the barium titanate scaffold produse with foam casting method coated with gelatin nano hydroxyapatite composite structure suitable for use in bone tissue engineering.

Volume 18, Issue 6 (11-2016)
Abstract

 As the world’s second saltiest lake, Urmia Lake is the main source of halotolerant unicellular microalga, Dunaliella, in Iran. Recently, this lake and, consequently, its biodiversity are being threatened environmentally. Hence collecting, preserving, and identification of indigenous microorganisms of the lake are of great importance. The objective of the present study was the molecular screening of Dunaliella isolates in Urmia Lake. For this purpose, 32 samples were taken from different geographical regions of the lake. Then, their molecular pattern was examined based on 18S rDNA gene and intron-sizing method. Results based on conserved and species-specific primers of 18S rDNA illustrated that, depending on the various parts of the lake, the genetic variation of Dunaliella population differs. The amplified pattern for individual isolates was similar to that previously described for D. tertiolecta, D. bardawil and Dunaliella sp. ARIINW-M1/2. Also,18S rDNA sequencing and phylogenetic analysis of five index isolates showed that the isolates Dunaliella sp. ABRIINW-Ch5, -Sh6.3 and -U1/1 were grouped with different intron lacking species of Dunaliella, ABRIINW-Ch3.1 was clustered with Dunaliella sp. ABRIINW-M1/2, while the isolate Dunaliella sp. ABRIINW-S1.5 was clustered with intron-harboring species of D. bardawil, D. parva, and D. viridis. The results indicated that Urmia Lake is composed of isolates with different 18S rDNA profiles with various intron arrangement. 

Volume 19, Issue 3 (March 2019)
Abstract

In this study, a three-dimensional (3D) Peano series solution is presented for the dynamic analysis of functionally graded (FG). Layered magneto-electro-elastic (MEE) plates resting on elastic foundations with considering imperfect interfacial bonding and the interfacial imperfection is modeled using a generalized spring layer method. Regardless of the number of layers, the equations of motion, Gauss’ equations (for electrostatics and magnetostatics), and the boundary and interface conditions are satisfied exactly. In this method, no assumptions on deformations, stresses, magnetic and electric fields along the thickness direction are introduced. Finally, the governing partial differential equations are solved using state-space method. The proposed formulation is validated through comparison with other available results. Effects of a two-parameter elastic foundation, gradient index, bonding imperfection, applied mechanical and electrical loads on the dynamic response of the functionally graded magneto-electro-elastic (FGMEE) plate are discussed The obtained exact solution can be used to assess the accuracy of the theorems for layered FGMEE plates and validating finite element codes.


Volume 21, Issue 2 (February 2021)
Abstract

To determination of equal-channel angular pressing(ECAP) process on the stress-strain behavior of  steel core of steel/copper bimetal and also effect of Cu-shell thickness on the created surface stretch during ECAP, the bimetallic samples composed of steel rods with 8 mm diameter and copper shells with 0.75 mm thickness are prepared. The both bimetallic samples and steel rods with 9.5 mm are subjected to consecutive ECAP process using die with inner angle 90o and an outer curvature corner angle of 30o. The applied load and punch displacement are recorded during samples passing through an ECAP die. The tensile testing is carried out on both the initial and ECAPed series. Moreover, dependence of surface stretch to diameters, shell thickness and strength properties of constituents of core/shell bimetallic rods is analytically modeled. Then, the finite element method(FEM) is used to investigate the effect of Cu-shell thickness. The obtained results revealed that the ultimate tensile strength of bimetallic core and steel rods are improved approximately 60% and 108% by ECAP deformation, respectively. The applied punch load for passing of bimetallic sample through an ECAP die is 54% less than the ones for steel rod. According to the FEM results, the maximum value of surface stretch is linearly decreased with increasing the thickness of copper shell. The obtained results show a good agreement between the analytical model and FEM approach.

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