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Showing 33 results for emadi


Volume 1, Issue 1 (3-1990)
Abstract

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Volume 2, Issue 1 (Spring & Summer 2025 2025)
Abstract

The political discourse of Islamism in Tunisia, which has roots in the intellectual tradition of the Muslim Brotherhood, has undergone significant changes over time, especially following the 2011 revolution. After a brief period of rule from 2011 to 2014, the moderate Islamists led by the Ennahda Movement gradually moved away from the revolutionary and ideological foundations of political Islam and adopted a more pragmatic approach. This study aims to explain how this transition from revolutionary political Islam to pragmatism can be understood. Using MacIntyre's epistemological framework, the analysis suggests that this shift is not merely a tactical political move but also reflects an epistemological crisis within the leaders’ reading of the Brotherhood’s intellectual tradition. Confronted with complex societal crises, Ennahda leaders recognized that solutions based solely on past principles and beliefs were no longer viable. Instead, they saw the need to reassess and reinterpret the Islamic intellectual tradition to address current shortcomings. Their reinterpretation was less about expanding the possibilities within the tradition and more about distancing themselves from traditional principles and criteria, favoring pragmatism and political realism. This reveals that Islamist leaders lack the necessary analytical and intellectual tools to effectively address societal crises, which hindered their ability to develop a systematic and coherent model of Islamic governance grounded in traditional criteria. Going forward, their potential role in Tunisia’s future depends on their capacity to equip themselves with the intellectual tools needed to confront emerging issues and challenges.
 

Volume 7, Issue 3 (Summer 2019)
Abstract

Aims: Breast cancer is the most common cancer in women in several countries. Bioactive peptides have demonstrated their cytotoxic potential in numerous cancer cell lines. In the search for novel bioactive peptides for pharmacological properties, crab is noncommercial protein-rich species. Using enzymatic hydrolysis is an efficient way to recover potent bioactive peptides from marine sources.
Materials and Methods: The aim of this study was to isolate fractions from rocky shore crab hydrolysate with desired molecular weight by ultrafiltration and investigate their cytotoxic activities. Four fractions (>30kDa, 10-30kDa, 3-10kDa and <3kDa) were evaluated for cytotoxic activity against a 4T1 cell line by MTT assay.
Findings: The MTT assay showed that although all fractions from the crab hydrolysate showed some activity, the low molecular weight samples (3-10kDa and <3kDa) were more effective than high molecular weight fractions (>30kDa and 10-30kDa) while the 3-10kDa fraction proved to be the most effective. The low molecular weight fractions significantly reduced the viability of the 4T1 cell lines in a dose-dependent manner upon 24 and 48h. The results were recorded in IC50 values of about 0.40±0.063mg mL-1 for <3 and 0.25±0.026mg mL-1 for 3-10kDa fractions.
Conclusion: Peptide fractions were isolated from the protein hydrolysate of the rocky shore crab Grapsus albolineatus are able to inhibit cancer cells and can be considered as a novel agent in nutraceutical and pharmaceutical ingredient applications.
 


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 (1-2006)
Abstract

The English narrative of "the adventure of Hajji Baba of Ispahan"[1] seems to be one of the controversial literal texts for the Iranian readership with social criticism interest. This paper intends, not to refute or redeem the validity claims of this historical actualized reading or to offer an alternative, but, to put it into perspective of a spectrum of possibilities and to show how and under what contingencies, the text can actualize some other rival and salient interpretations that reverberate our contemporary horizons of social reality. Using the Ricoeurian theories of literature by applying his theory of "surplus of meaning" on the text we suggest how "The World of Text " has the potential to have different readings and in the next step, by analyzing "The World of Reader" and its dialectical relations with the world of text, we exhibit the important role of "reading" as the act of Self Reflection.

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.

Volume 13, Issue 3 (Number 3 - 2011)
Abstract

In order to provide the data needed for the design of saffron processing equipment, physical properties of its flower were investigated. These properties included dimensions, mass, true and bulk densities, porosity, static and dynamic coefficients of friction, and terminal velocity as a function of moisture content. The average range of these properties for the three different parts of saffron flower was about 0.03 to 0.16 gcm-3 for bulk density, 0.55 to 1.56 gcm-3 for true density, and 85.2 to 95.5% for porosity. Also, the coefficients of friction were measured for three flower parts by using three surface materials including plywood, iron, and galvanized steel sheets. The minimum and the maximum values of static coefficients of friction were found on galvanized steel sheet. They were 0.8 and 2.14 for anther and stigma, respectively. The dynamic coefficient of friction ranged from 0.45 for anther on iron to 1.14 for petal on galvanized steel sheet. The variation range of terminal velocity for three different parts of the flower was recorded between 0.9 and 2.38 ms-1. The results of friction coefficients and terminal velocity measurements suggest that, based on these properties, design of a separator for saffron flower parts is feasible.

Volume 13, Issue 6 (January & February 2023 2022)
Abstract

Stress is a linguistic property of a word that specifies which syllable in the word is stronger than any of the others. Early studies such as Fry (1955, 1958), Lieberman (1960), Beckman (1986), Harrington, Beckman, and Palethorpe (1998) (see also Laver, 1994 for an overview) have shown that there are clear acoustic differences between stressed and unstressed syllables: stressed syllables are realized with higher pitch, higher intensity, longer duration, and more peripheral vowel quality than unstressed syllables. Studies in many stress-accent languages show that the stressed realization of a syllable differs from the unstressed realization of the same syllable by having higher pitch. Also, results have showed that speakers consistently use duration to distinguish between open and central vowels that contrasted in stress at the word level. In contrast with F0 and duration, the relation of intensity variation in the speech signal to word stress is still controversial.
In this paper, we investigated the role of acoustic factors involved in perceptually differentiating simple past from present perfect verbs in Persian, through manipulation of fundamental frequency (F0) and duration. Thus, tokens were resynthesized from the phonetic forms of Persian simple past and present perfect verbs in which F0 and duration were manipulated in several steps. The target tokens were presented to some native Persian participants to identify as simple past or present perfect. Results suggested that Persian listeners’ judgements of the tense of the target tokens depend, to a great extent, on the local F0 values of the verbs’ syllables as any amount of increase in the local F0 points of the respective syllables can categorically change the listeners’ judgements about the temporal reading of the verbs involved. On the other hand, results for duration showed that values of this parameter fail to produce a significant effect on listeners’ judgements.  
1. Introduction
Stress is a linguistic property of words. It specifies the syllable that is stronger than any of the others. Early studies have shown that there are clear acoustic differences between stressed and unstressed syllables: stressed syllables are realized with a higher pitch, higher intensity, longer duration, and more peripheral vowel quality than unstressed syllables (Sluijter and van Heuven, 1996). Studies in many stress-accent languages show that the stressed realization of a syllable differs from the unstressed realization of the same syllable by having a higher pitch. Also, results have shown that speakers consistently used duration to distinguish between open and central vowels that contrasted in stress at the word level, while stress contrast between open vowels at the sentence level was mainly cued by the accompanying intonational prominence contrast. In contrast with F0 and duration, the relation of intensity variation in the speech signal to word stress is still controversial. On the one hand, previous work has generally emphasized that intensity manipulations prove much weaker cues than duration in stress perception. On the other hand, several different operationalizations of intensity such as intensity summed over time (Beckman, 1986) and spectral tilt; i.e., the degree to which intensity changes as frequency increases (Sluijter and van Heuven, 1996a; Sluijter, van Heuven, and Pacilly, 1997), are consistent correlates of stress. For example, Sluijter and van Heuven (1996) argue that previous research which has shown loudness variation to be virtually inconsequential for stress perception is usually based on analyses that do not distinguish between word stress, on the one hand, and prominence resulting from pitch accent on the other. They notice that the traditional account of stress as a local increase in loudness seems justified if a more accurate measure of intensity is chosen.
Simple past and present perfect verbs in Persian are segmentally similar in colloquial speech and only different in terms of the stress position. The morphological structure of present perfect in Persian incudes two verbal morphemes: (1) the perfect marker /-e/ and (2) person and number marker. In colloquial speech, the perfect marker /-e/ is deleted and the following vowel (e.g., the vowel of the person and number marker) is pronounced longer than usual.
The present study is intended to investigate how simple past and present perfect verbs in Persian colloquial speech are acoustically differentiated and to what extent the acoustic cues to verb morphological identity are used in perception.  We hypothesized that both F0 and duration can be used as reliable acoustic cues to perceptually distinguish simple past and present perfect verbs in Persian. The research is innovative in that it is the first experimental study that investigates the phonetic differences between simple past and present perfect verbs in Persian. 

2. Methodology
In a perception experiment, we investigated the role of acoustic factors involved in perceptually differentiating simple past from present perfect verbs in Persian, through manipulation of fundamental frequency (F0) and duration. Thus, tokens were resynthesized from the phonetic forms of Persian simple past and present perfect verbs in which F0 and duration were manipulated in several steps. The target tokens were presented to some native Persian participants to decide whether they are simple past or present perfect. Twenty speakers of Standard Persian (10 male and 10 female) participated in the perception experiment.
Fundamental frequency and duration were examined in a perception experiment as the potential parameters (based on the production experiment) to distinguish between simple past and present perfect. Two verbs were chosen from the production experiment to be manipulated in three ways through several steps.
The first type of stimuli was created through 5 ten-Hz steps by increasing peak height of syllable A in simple past verbs (from 210 to 250 Hz and from 130 to 170 Hz for the verb /dozdidænd/ “steal-Past-3rd PL” and /dʒængidænd/ “fight- Past-3rd PL”, respectively) (Fig. 2). The second type of stimuli was made by increasing peak height of syllable B in present perfect verbs through 5 steps (from 134 to 184 Hz and from 133 to 173 Hz for the verbs “dozdidænd/ “steal-Past-3rd PL” and /dʒængidænd/ “fight- Past-3rd PL”, respectively (Fig. 2). Finally, the height of peak was kept constant for the respective verbs and the duration of syllable A in simple past verbs was increased through five 12-ms steps. The same procedure was applied for syllable B in present perfect verbs (Fig. 3).

3. Results
Results showed that the stimuli are perceived as simple past where syllable A is at least 15 Hz higher in pitch than syllable B. According to the results, the stimuli are perceived as present perfect where syllable B is at least 10 Hz higher in pitch than syllable A. Finally, the matching judgements for the stimulus pairs based on duration showed that the steps of duration yielded about 50 % identification responses irrespective of the type of stimuli (simple past or present perfect).   
   
4. Conclusion
In general, the results of the perception experiment carried out in this research suggested that Persian listeners’ judgements of the tense of the target tokens depend, to a great extent, on the local F0 values of the verbs’ syllables as any amount of increase in the local F0 points of the respective syllables can categorically change the listeners’ judgements about the temporal reading of the verbs involved. On the other hand, results for duration showed that values of this parameter fail to produce a significant effect on listeners’ judgements.

 

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 14, Issue 62 (4-2017)
Abstract

In this study, Response Surface Methodology (RSM) was used for optimization of the conditions for hot air drying of pear slices with osmosis pretreatment. The effects of two parameters including drying temperature (50-70 °C) and drying time (240-360 minutes) as independent variables on moisture content, shrinkage percentage and rehydration ratio of pear slices as dependent variables (responses) were evaluated. The regression models for all responses were statistically significant at the 99% confidence level and lack of fit was not significant. All process variables had linear effect on all the responses (p <0.01). Also the quadratic term of drying temperature on rehydration ratio was significant. The optimum conditions obtained for minimum moisture content and shrinkage percentage and maximum rehydration ratio were: 39.60 °C as drying temperature and the drying time of 360 minutes. In optimized condition, the moisture content, rehydration ratio and shrinkage percentage of dried pear slices were 26.17%, 1.62 and 77.31 respectively.

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