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Showing 49 results for Fani
Volume 18, Issue 1 (5-2014)
Abstract
Over the years, political behavior has been one of topics of interest to researchers in the field of organizational behavior. The reason for this interest is the extensiveness of this type of behavior in the organizations. This study, with regarding political skill and political will as moderating variables, considers the impact of perceptions of organizational politics on political behavior. The statistical population consists of managers and workers of water industry. In this research, the stratified (classified) sampling is used. To collect data, the questionnaire from five-option Likert scale was used, and the validity and reliability for each variable were confirmed. The data analysis was done by structural equation modeling, and path analysis by using LISREL software and Smart PLS. The results showed that perceptions of politics lead to political behavior, and political will moderates the relationship between the perceptions of politics and the political behavior. In this research, the moderating role of political skill was not confirmed. Keywords:
Volume 18, Issue 2 (4-2018)
Abstract
In this study, the performance of direct absorption solar collector is experimentally investigated using Fe3O4/Silica hybrid nanofluid based on deionized water. First, stability of prepared nanofluids is considered using spectral absorbency method. Then, spectrophotometry method is used for measuring optical properties of nanofluids. A prototype of this new type of collector was built with applicability for solar water heating systems. The procedure of EN 12975-2 standard was used for testing the thermal performance of the collector. Results show that collector efficiency is enhanced by nanofluid concentration, so that collector maximum efficiency is 73.9%, 79.8% and 83.7%using nanofluid with concentration of 500 ppm, 1000 ppm and 2000 ppm, respec/tively. This vaule is 63% using the base fluid as working fluid. Regarding very low volume fractions of nanofluids used in direct absorption solar collectors, the viscosity of the base fluid experience insignificant increase, therefore, pumping power will not increase significsantly. Such increase in efficiency show that direct absorption solar collector performance using hybrid nanofluid is much better than that of using the water at the same operating conditions. Application of stable hybrid nanofluid results in higher conversion efficiency of solar energy to useful energy.
Volume 18, Issue 2 (4-2018)
Abstract
In this paper, the three dimensional ventilated cavitating flow in the steady condition around a projectile model is simulated using CFD method combined with a sst k-ω turbulence model and volume-of-fluid technique, With the aid of CFD software ANSYS CFX. The numerical model is validated using comparisons between numerical predictions and existing experimental data and fairly good agreement is revealed. The numerical results show that with increasing the ventilation gas rate at constant Froude number, the cavity length gradually increases to a critical value and then remains fixed upon further increase in gas ventilation rate. Also, it has been observed that rear portion of larger cavity moves upwards due to gravitational effect. With increasing the ventilation gas rate, the gas leakage mechanism at rear portion of ventilated supercavity changes from the re-entrant jet closure mode to twin vortex closure mode. The variation of ventilation gas rate versus cavity length is a function of Froude number and the critical ventilation gas rate increases linearly with Froude number.
Dr Alireza ErFani, Dr Hossein Tavakolian, Azadeh Talebbeydokhti,
Volume 18, Issue 4 (winter 2018 2018)
Volume 18, Issue 4 (winter 2018 2018)
Abstract
Today, achieving financial stability alongside stabilizing inflation and output is of particular importance among monetary policymakers and regulatory authorities. In this study, a Dynamic Stochastic General Equilibrium Model was used for the period 1990: 1 to 2014: 4 in the economy of Iran, in which a measure of financial shock was also introduced. In this model, the financial shock is modeled as a reduction in external financing premium of the firm. Comparison of the performance of policy rules showed that following an expansionary financial shock, macro-prudential policy regime, in which instruments of monetary policy and macro-prudential policy deal with excessive growth of credit, leads to a significant reduction in the external financing premium of the firm. This in turn leads to less volatility in economic variables, such as inflation and output. This would improve the welfare in the Economy of Iran.
Volume 18, Issue 7 (11-2018)
Abstract
In this study, energy and exergy efficiency of residential-type direct absorption solar collector using PVP-coated silver nanofluid has been evaluated experimentally. First, stability and thermophysical and optical properties of nanofluid have been considered using the theoretical and experimental methods. Then, outdoor thermal performance of collector is investigated using the experimental setup based on EN12975-2. Results of energy analysis show that the collector efficiency is increased by increase of flowrate and concentration of nanofluid asymptotically. It is observed that exergy efficiency is firstly increased by nanofluid concentration and then, decreased after reaching the optimum value. The optimum concentration was 500 ppm for all flowrates. The variation of exergy efficiency by reduced temperature difference is similar to volume fraction. The optimum exergy efficiency is obtained at 0.01 m2K/W. The decrease of exergy efficiency by flowrate indicated that exergy losses due to pressure drop have the significant effect on the collector performance.
Volume 19, Issue 2 (7-2019)
Abstract
The purpose of this study is to develop the previous proposed analytical model by the first and second authors for short links, so it can be used for all kinds of links including short, intermediate, and long links. Eccentrically braced frames (EBF) offer high lateral stiffness because of their braced configuration while also providing high ductility and energy dissipation. They are widely used as a lateral-force resisting system for multi-story buildings located in seismic areas. The key components of the EBF system include columns, collector beams, braces and active links. The active links are designed to provide ductility and energy dissipation through yielding under design basis earthquakes, while all other structural members are designed to be stronger than the links and stay in elastic range. The link is defined by a horizontal eccentricity between the intersection points of the two brace centerlines with the beam centerline. Sufficient analytical model which can accurately predict the inelastic performance of the links is needed to perform reliable nonlinear analyses of EBFs. Analytical models that are used to study the inelastic seismic response of the EBFs usually reflect the anticipated behavior of the different frame elements. Links are modeled as inelastic elements with concentrated end flexural and shear hinges. Beams outside of the link, braces, and columns are typically modeled as elastic beam-column elements, because no inelastic behavior is anticipated in design. Ricles and Popov proposed an analytical model for short links. Ramadan and Ghobarah replaced the sub-hinges with translational and rotational springs and proposed a new model. Both models had incorrect shear stiffness so that the shear stiffness of model was half the link shear stiffness. Richards and Uang corrected the shear stiffness of the model proposed by Ramadan and Ghobarah, and proposed a new analytical model for short links. Koboevic et al. proposed an analytical model based on the results of experimental test performed by Okazaki and Engelhardt, regardless of the fact that the actual measured dimensions of sections were different from the standard dimensions of sections. To account for this issue, despite of what is said in their paper, the strain-hardening ratio was set to 0.0045. For this reason, the shear stiffness of their proposed model was incorrect and the predicted shear forces are 15 to 24 percent more than the experimental shear forces. Ashtari and Erfani showed that available analytical models do not predict very well the maximum shear forces and deformations too, and proposed an analytical model which can accurately predict both maximum and intermediary values of shear force and deformation of short links. To the authors’ knowledge, currently there are only suitable analytical models for short links. In this study an analytical model which can accurately predict both maximum and intermediary values of forces and deformations for short, intermediate, and long links, is proposed. The parameters of model are established based on test results from several experiments on links and EBFs. Comparison of available test results with the hysteresis curves obtained using the proposed analytical model established the accuracy of the model. The proposed model is recommended to be used to perform inelastic analyses of EBFs.
Volume 19, Issue 127 (September 2022)
Abstract
In order to evaluate the quality and quantity of some important commercial Iranian pomegranate cultivars, in the climatic conditions of Yazd, the fruits of 12 cultivars including: Ardestani Mahvalat, Bejestani, Shishekap Ferdows, Naderi Badroud, Qajaq Qom, Gel Tafti, Shirin Shahvar, Robab Neyriz, Malase Yazdi, Malase Saveh, Malase Yousefkhani and Khazar Bardaskan were harvested at commercial maturity stage and were evaluated for important quantitative and qualitative traits. The results showed, there were significant differences among the cultivars in terms of fruit weight, skin and aril color properties (CIE L *, a *, b * and Hugh angle), soluble solids content, titratable acidity, antioxidant activity and anthocyanin content. Meanwhile, the highest fruit weight was measured in Shirin Shahvar cultivar, this cultivar also had the lowest titratable acidity and the highest taste index among the cultivars, and also this cultivar showed a bright color, however, the brightest color among the cultivars was observed in Naderi Badroud. Based on the skin and aril color properties, anthocyanin content and fruit taste, Malase Yazdi was the best among the cultivars. However, cultivars such as Shishekap Ferdows, also showed good quality characteristics. Also the correlations between traits was investigated and significant relationships were observed between color properties and amount of anthocyanin or between antioxidant capacity and amount of phenol or amount of anthocyanin.
Volume 19, Issue 132 ( February 2023)
Abstract
In this study, biodegradable film was prepared from polyvinyl alcohol. Silver chloride nanoparticles and spirulina algae powder were used to modify the physicochemical structure and create antioxidant activity in the film. The surface morphology of the film was investigated. Polyvinyl alcohol film and its composites were used for packaging virgin olive oil. D-optimal design was used to investigate the effect of packaging type and storage time on the chemical, color and sensory characteristics of the oil. Chemical characteristics (acidity, peroxide value, refractive index and total phenol), sensory and color characteristics were investigated. The response surface method was used to investigate the effect of independent variables on the oil as well as the created mathematical models. The obtained results showed that in polyvinyl alcohol film modified with silver chloride particles and polyvinyl alcohol modified with silver chloride and spirulina particles, the presence of these particles on the surface of the film was completely evident. The results of the chemical, sensory and color analysis of the oil showed that the chemical, sensory and color quality of the oil decreased with the increase in the storage time of the oil in all packages. Peroxide value as the most important indicator of the quality of oils in normal packaging increased from 1 to 7 (mEq O2/Kg oil) during 30 days of storage, while in oil packaged with polyvinyl alcohol modified with silver chloride and spirulina algae, this increase was from 1 to 2 (mEq O2/Kg oil). In general, oils packaged with polyvinyl alcohol modified with silver chloride and spirulina algae showed the least quality changes compared to normal packaging, which indicates the ability of these films to control the quality and increase the shelf life of virgin olive oil.Volume 20, Issue 136 (June 2023)
Abstract
Abstract
Increasing and improving the stability of colors in food during processing and also controlling the release until consumption is one of the most important issues and challenges in the use of natural colors in food. Hence, the objective of this study was to produce phytocyanin-containing nanoliposomes coated with chitosan by thin-layer ultrasonic hydration method to increase the stability of phycocyanin and to investigate its physical properties and encapsulation efficiency during storage. In this study, phycocyanin was coated with different concentrations of chitosan (0, 0.1, 0.2, 0.4, and 0.6 mg/mL) and stored at two temperatures (4 and 25° C) for 28 days. Then, to determine the best concentration of chitosan for coating the nanoliposomes, encapsulation efficiency, particle size, and zeta potential tests were performed. The results revealed that by increasing the concentration of chitosan to more than 0.2 mg/mL, no significant change in encapsulation efficiency was observed (p> 0.05). The sample without chitosan had the lowest particle size which was not a significant difference from samples containing 0.2 and 0.4 (p> 0.05). Increasing chitosan in the coating of nanoliposomes has led to increased zeta potential. Finally, a sample containing 0.2 mg/mL chitosan was selected as the best sample. Findings from analyses performed during the storage of nanoliposomes showed that nanoliposomes containing phycocyanin, which did not have any chitosan coating, had the highest encapsulation efficiency. On the other hand, it was found that with increasing storage temperature and storage time, the encapsulation efficiency decreased but the particle size increased. The lowest zeta potential of the samples was related to the phycocyanin-free nanoliposome sample which did not change significantly until the 21st day of storage at 4 °C. Scanning electron microscopy (SEM) images of the samples also confirmed the results of particle measurements.
Volume 20, Issue 141 (November 2023)
Abstract
In fish processing industries, 50-70% of primary fish are produced as waste, while they are rich sources of protein and essential amino acids. The optimal use of these wastes and the production of compounds with high added value that have significant health-giving properties is one of the important challenges of fish processing industries. In this research, the effect of hydrolysis conditions (time: 30-300 minutes and enzyme concentration 0.5-3%) and type of protease (pepsin and trypsin) on the degree of hydrolysis and antioxidant properties (DPPH radical scavenging activity, Fe chelating activity, No radical scavenging activity, total antioxidant capacity and Fe reducing power) of hydrolyzed protein obtained from Skipjack viscera were evaluated using response surface methodology. The results showed that the optimal conditions for the production of hydrolyzed protein with the maximum antioxidant properties with pepsin and trypsin enzymes were respectively: hydrolysis time of 179.09 and 143.62 minutes and enzyme concentration of 2.63 and 1.94 %; In this condition, the degree of hydrolysis of the hydrolyzed proteins resulting from the activity of trypsin was calculated to be higher than that of pepsin. Comparing the antioxidant properties of the hydrolysates obtained from the two enzymes used showed that the hydrolyzed protein obtained from trypsin had a stronger antioxidant potential than pepsin. Therefore, it can be stated that the hydrolyzed protein of the Skipjack viscera using trypsin enzyme as a health-giving supplement and with high added value can be used in the production of functional food products and health supplements for athletes and elderly people.
Volume 20, Issue 143 (January 2023)
Abstract
The seeds of Cucurbitaceae plants (pumpkin, melon, etc.) are one of the rich sources of protein. Proteins are one of the most important nutritional sources for humans. Enzymatic hydrolysis of pumpkin seed protein by using microwave pretreatment leads to the production of hydrolyzates with bioactive properties, including antioxidant activity. The use of microwave pretreatment causes changes in the 3D structure of proteins, It opens the 3-dimensional structure of the protein and accelerates the access of the enzyme to the peptide bonds. Therefore, the use of microwave pretreatment is a suitable method to save time and enzyme concentration which are used in enzymatic hydrolysis. In this study, The solution of pumpkin seed protein concentrate was exposed to microwave energy with a power of 500-900 W for 30-90 seconds and it was used as a substrate solution in enzymatic hydrolysis experiments. Enzymatic hydrolysis by pancreatin, with the concentration of 0.5 to 2.5% compared to the protein substrate, was performed in the time from 20 to 190 minutes, at the optimum temperature and pH of pancreatin, in order to produce hydrolysates with antioxidant potential. Antioxidant power was measured by using DPPH radical scavenging activity methods, total antioxidant activity (Absorbance at 695 nm) and iron chelating activity. The highest amount of antioxidant activity by using microwave pretreatment was in 105 minutes and the ratio of 1.5% E/S and the optimal conditions that provided by the software to achieve the maximum iron chelating activity (95.5%), DPPH radical scavenging activity (51.5%) and total antioxidant (Absorbance at 695 nm) (0.976), was in 102 minutes and the ratio of 1.5% E/S of which 89.5% corresponded with the obtained results.
Volume 20, Issue 144 (February 2024)
Abstract
Oxidation in living organs causes dangerous diseases, including cancer, and in food, it causes spoilage and heavy economic losses. Synthetic antioxidants have adverse and dangerous effects on human health, therefore identifying natural antioxidant compounds is one of the main needs of the food industry. In fish processing industries, about 50-70% of fish, which are potential sources of valuable nutritional compounds such as essential amino acids, are produced as waste. Therefore, finding a way to optimally use these wastes and produce healthy compounds with high added value such as bioactive peptides has great importance. In this research, the effect of hydrolysis conditions (time: 30-300 min and enzyme concentration 0.5-3 %) and type of protease (alcalase and pancreatin) on the degree of hydrolysis and antioxidant properties (DPPH radical scavenging activity, Fe chelating activity, nitric oxide radical inhibition, total antioxidant capacity and Fe reducing power) of protein hydrolysate from skipjack viscera was investigated using the response surface methodology. The results showed that the optimum conditions for achieving the most antioxidant properties with alcalase and pancreatin were: hydrolysis time of 146.9 and 171.67 minutes and enzyme concentration of 1.94 and 2.17%; in these conditions, the degree of hydrolysis of the produced protein hydrolysates was 25.12% and 20.35%, respectively. Comparing the antioxidant properties of hydrolysates produced by both proteases showed that the alcalase enzyme led to the production of protein hydrolysates with stronger antioxidant properties than pancreatin. Therefore, it can be concluded that the protein hydrolysate of the skipjack fish viscera using alcalase enzyme as a healthy and value-added product can be used in the production of functional products and health supplements.
Volume 21, Issue 2 (5-2021)
Abstract
There are some Innovative methods to control the damage caused by seismic loads, and one of them is to concentrate the damages on the designated region or members. The reduced beam section connection, also known as the dogbone connection, is a promising option for improving the ductility of steel beam to column moment connections, especially in high-risk regions. By symmetrically trimming the width of the beam flanges over a discreet length in the vicinity of the beam ends, a ductile fuse can be created to accommodate the inelasticity that is required for seismic energy dissipation while is not only protecting the beam to column connection but also prevent causing the catastrophic and progressive collapse of the structure. This paperchr('39')s emphasis is the performance of the steel portal frame with RBS connections based on detail provided by AISC specification. The concentration of plastic deformations in the RBS region under cyclic load causes intensified stresses that accumulate damage. The prediction of ductile damage and fracture is one of the most important challenges in many engineering applications. Damages in a structure are caused by material degradation due to initiation, growth, and coalescence of microcracks/voids in a real-life material element from monotonic, cyclic/fatigue, or dynamic/explosive impact loading. The damage evolution law describes the rate of degradation of the material stiffness once the corresponding initiation criterion has been reached. In this study, the ductile damage model presented for steel is used. Damage Initiation parameters and damage evolution rules were obtained based on standard tensile test from literature and software procedure analysis. A coupon model has been established based on the standard tensile test to evaluate the ductile damage model. Also, to validate the steel portal frame with the RBS connection model two-step has been considered. In the first step, the global response of the steel moment frame was validated based on Wakabayashichr('39')s test. Also validation of the RBS connection model was checked based on Pachoumis experiments in the next step. Then, according to AISC 360 steel and AISC 341 steel, a steel moment frame design with RBS connection was designed. By selecting and extracting a single-span portal frame, the effect of considering damage was investigated by finite element analysis. Initial geometrical imperfections were determined using the AISC 360 Recommendation for out-of-plumbness, out-of-straightness, and localized geometrical defects. The cyclic displacement amplitude followed the loading protocol in the ATC-24. The study results show in the elastic region the behavior of the frame remains unchanged before the frame reaches the high amplitude cycle. But gradually, with increasing cycles, the size of the hysteresis loop and ultimate resistance became smaller. Thereby, if the aim is to focus on the load levels that lead to large localized plastic deformations, it is critical to consider the damage parameters to improve the reliability of the results. Measurement of the area below the graph in the last loading cycle shows that the dissipated energy in the two cases without vertical load and with a vertical load on the columns is decreased by 2.6% and 4.1%, respectively. The continued deterioration of the RBS region due to damage spreads leads to complete frame failure, which is not properly predicted when damage parameters are ignored.
Volume 22, Issue 1 (1-2020)
Abstract
Ghee, a nutritional dairy product in Iranian culture, can be easily produced on a small scale. This study was undertaken to analyze fatty acids and volatile compounds of collected ghee samples from different ghee production sites of Iran (Ilam, Kermanshah and Hamedan) using HeadSpace Solid Phase MicroExtraction (HS-SPME) technique. According to the results, palmitic and oleic acids were the dominant fatty acids in all the samples investigated. Further, it might be concluded that compounds such as dodecane, acetone, butyric acid, hexanoic acid, 2-pentanone, 2-heptanone, and 2-undecanone, which are present and might have accumulated as the results of oxidative, hydrolytic, or microbial activities, contribute to the flavor of ghee. Lactones, which are produced at high temperatures, were not collected in any sample except the Hamedan sample (< 1%). Low thermal processing in the ghee production prevented the formation of off-flavor volatile compounds. The qualitative and quantitative parameters determined in this study might be useful in assessing the quality of the ghee and may help the industry to improve its commercial production.
Volume 23, Issue 1 (1-2021)
Abstract
Spatially explicit estimates of aboveground biomass over large area are necessary for natural resources managers. This study examined aboveground biomass and carbon stock of the wild pistachio (Pistacia atlantica) based on individual tree crown detection and allometric development in the arid woodlands using high-resolution satellite images of GeoEye-1 in a reserved forest area of Wild Pistachio trees in the South Khorasan Province, East of Iran. Biomass of sampled trees was determined using field sampling and experimental tests. In addition, the biomass of stems was determined using volume and density. The allometric biomass and carbon stock equations of Wild Pistachio trees were developed based on crown area, diameter at breast height (1.3 m), and height of trees. The trees crowns were detected and delineated on the GeoEye-1 images, using local maxima filters, and region growing segmentation algorithms, respectively. In addition, a morphological watershed transformation method was applied to split the connected and overlapped tree crowns. Performing algorithms was assessed using the measured field crown of sample trees by precision, recall, and overall accuracy indices. The biomass and carbon stock of trees of the study area were estimated using delineated crown area and the developed allometric equations. The results showed that the equation that used crown area could explain more than 80% of the remarked variation in biomass and carbon stock. In addition, the crown detection method results showed that overall detection rate and the quality of crown boundaries were acceptable. In conclusion, the study confirmed that combining the allometric equations with crown information from high-resolution images could contribute to the explicit mapping of biomass and carbon stock of wild pistachio trees in the arid woodlands.
Volume 24, Issue 1 (Spring 2020)
Abstract
Introduction
In Iran,time is limited and it is always too late to modify management attitudes in the fields of environment. On the one hand, the relevant agencies do not even know their priorities separately or are unaware relationship of their priorities with other agencies, while at the macro level, they are unaware of the province's development plan. So, important drivers in the field of environment are the first and most important steps in guiding scenarios of proper management.
Methodology
First, a list of effective drivers of environmental management in the South Khorasan province was collected from some specialist and experts using Delphi, followed by two-dimensional matrices containing quantitative matrices to quantify the driver’s relationships and interpretations. The axes of influence and dependenceare were used. Therefore, according to the position of each driver with these two criteria in the matrix, five types of drivers are defined. Drivers screening based on the degree of influence and dependence of other drivers as effective , key and independent drivers in the field of environmental management in South Khorasan province were studied. The method used was MicMac Structural Analysis, which was used by academic experts and related executives. In so doing, the team created a common language which will served them as the process continued. In most cases, it also allowed the team to redefine certain variables and refine the analysis of the system. Lastly, experience shows that the ideal percentage of the matrix to be filled-in is around 20%.
Comparing the rankings of the variables from the various classifications (direct, indirect and potential) is a rich source of information. It allows the team to confirm the importance of certain variables as well as to reveal those variables which play a dominant role in the system, and which would have remained undetected if they had only been compared directly. The information obtained by influence and dependence of each of the variables can be displayed in two-dimensional diagrams containing the vertical (affective) and horizontal (affective) axes. This method can identify the most effective drivers in the system and study the different roles played by these drivers (Godet & Durance, 2011).
Results and discussion
By aggregating and analyzing the views of a panel of experts in the field who know the topic in MicMac 39 software, drivers were identified as key, effective, effective and dependence drivers. The comments were considered as MicMac inputs, with a filling rate of 23.86% including 153 one (weak influence), 113 two (moderate influence), 89 three (strong influence) and 8 to P (possible influence). The sum of direct and indirect and probable influence of drivers were estimated to be 3007, 2805, 2135, 1938 and 1572, respectively. This matrix has 100% stability with two replications which shows high validity of the questionnaire and its answers. The directinfluence (a) and indirect (b) influence of the drivers on each other are shown in Fig. 1.
Driver 5 (D5: creating environmental law enforcement and warranties) and D1 (co-operation between related agencies to prevent any re-work) in four ways are among the most effective and determining factors. In the next step, the influence of the drivers of the free flow of information and sharing the results of studies of all environmental-related organizations to public or academic expertise (D33), changing the real attitude of decision-makers in embracing intellectual physical potential, and creative indigenous peoples of the region (D29) and the environmental agency's correct placement in decision making (before doing the project and any action not after it is finalized or completed!) (D6) were more influence drivers respectively.
Given that the distribution of drivers is in the axis of influence and dependency as L shape, the system under study is balanced and it is possible to make planning for such a system (Arcade et al., 1999; Erfani and Mircheraghkhani, 2018)
Conclusion
Five main and key drivers of the system under study were identified, the first two of which relate to political and institutional domains that are in line with Erfani and Mircheraghkhani’s (2018) study. In this study, monitoring of nine identified response drivers is the main indicator for revealing the province’s environmental management status, which is recommended for future studies. These indicators can explain the environmental status of the province and can be considered as a criterion for determining the actual performance and efficiency of the agencies. It is also recommended to continue the present study and to complete four more steps from the LIPSOR School to identify conflicts of interest between relevant stakeholders, scenarios building and predict the future.
Each year, the performance statistics of the agencies are presented based on the indicators set by the agencies themselves and the overhead agencies, and they are more likely to be defined in a way that may not adequately represent the agencies’ performance, and thus make the agencies less judgmental to fall. For example, the index of mountain tenure has clearly increased over the last few years. Combating mountain tenure alone does not indicate management efficiency, but rather the absence of mountain tenure and the return of shifting areas given to conditions close to the baseline status is effective either. Therefore, change in decision makers' attitudes (D6) and efforts in problem solving have been introduced as one of the key drivers in this study (Fig. 1).
In Iran,time is limited and it is always too late to modify management attitudes in the fields of environment. On the one hand, the relevant agencies do not even know their priorities separately or are unaware relationship of their priorities with other agencies, while at the macro level, they are unaware of the province's development plan. So, important drivers in the field of environment are the first and most important steps in guiding scenarios of proper management.
Methodology
First, a list of effective drivers of environmental management in the South Khorasan province was collected from some specialist and experts using Delphi, followed by two-dimensional matrices containing quantitative matrices to quantify the driver’s relationships and interpretations. The axes of influence and dependence
Comparing the rankings of the variables from the various classifications (direct, indirect and potential) is a rich source of information. It allows the team to confirm the importance of certain variables as well as to reveal those variables which play a dominant role in the system, and which would have remained undetected if they had only been compared directly. The information obtained by influence and dependence of each of the variables can be displayed in two-dimensional diagrams containing the vertical (affective) and horizontal (affective) axes. This method can identify the most effective drivers in the system and study the different roles played by these drivers (Godet & Durance, 2011).
Results and discussion
By aggregating and analyzing the views of a panel of experts in the field who know the topic in MicMac 39 software, drivers were identified as key, effective, effective and dependence drivers. The comments were considered as MicMac inputs, with a filling rate of 23.86% including 153 one (weak influence), 113 two (moderate influence), 89 three (strong influence) and 8 to P (possible influence). The sum of direct and indirect and probable influence of drivers were estimated to be 3007, 2805, 2135, 1938 and 1572, respectively. This matrix has 100% stability with two replications which shows high validity of the questionnaire and its answers. The direct
Driver 5 (D5: creating environmental law enforcement and warranties) and D1 (co-operation between related agencies to prevent any re-work) in four ways are among the most effective and determining factors. In the next step, the influence of the drivers of the free flow of information and sharing the results of studies of all environmental-related organizations to public or academic expertise (D33), changing the real attitude of decision-makers in embracing intellectual physical potential, and creative indigenous peoples of the region (D29) and the environmental agency's correct placement in decision making (before doing the project and any action not after it is finalized or completed!) (D6) were more influence drivers respectively.
Given that the distribution of drivers is in the axis of influence and dependency as L shape, the system under study is balanced and it is possible to make planning for such a system (Arcade et al., 1999; Erfani and Mircheraghkhani, 2018)
Conclusion
Five main and key drivers of the system under study were identified, the first two of which relate to political and institutional domains that are in line with Erfani and Mircheraghkhani’s (2018) study. In this study, monitoring of nine identified response drivers is the main indicator for revealing the province’s environmental management status, which is recommended for future studies. These indicators can explain the environmental status of the province and can be considered as a criterion for determining the actual performance and efficiency of the agencies. It is also recommended to continue the present study and to complete four more steps from the LIPSOR School to identify conflicts of interest between relevant stakeholders, scenarios building and predict the future.
Each year, the performance statistics of the agencies are presented based on the indicators set by the agencies themselves and the overhead agencies, and they are more likely to be defined in a way that may not adequately represent the agencies’ performance, and thus make the agencies less judgmental to fall. For example, the index of mountain tenure has clearly increased over the last few years. Combating mountain tenure alone does not indicate management efficiency, but rather the absence of mountain tenure and the return of shifting areas given to conditions close to the baseline status is effective either. Therefore, change in decision makers' attitudes (D6) and efforts in problem solving have been introduced as one of the key drivers in this study (Fig. 1).
Volume 24, Issue 4 (April 2024)
Abstract
Waste heat dissipation from spacecraft subsystems is crucial due to spatial limitations (no convective heat transfer, limited electrical power, lightweight, and high reliability). Radiators are often responsible for collecting and dissipating this waste heat into cold space. Panel radiators are widely used in various satellites, including scientific, communication, and remote sensing satellites. In scientific satellites, panel radiators are used to dissipate heat generated by scientific instruments such as cameras and spectrometers. In communication satellites, panel radiators are used to dissipate heat generated by power amplifiers. In remote sensing satellites, panel radiators are used to dissipate heat generated by sensors and processors. High efficiency, light weight, and high reliability are the advantages of using this equipment. The main challenge in using it is to provide sufficient heat dissipation area and uniformity of the surface temperature when radiating waste heat to the cold environment (space). The use of heat pipes in the panel radiator structure provides this uniformity. A heat pipe radiator consists of a sandwich panel with an embedded network of heat pipes. Increasing the number of heat pipes reduces the temperature gradient across the radiator surface but increases the radiator weight. Due to the importance of equipment lightness in space systems, optimization of the number of pipes and their geometric arrangement in the radiator should be such that maximum temperature uniformity on the surface and minimum radiator weight are achieved. The objective of this research is to optimize the performance of a radiator (maximum temperature uniformity on the surface) to achieve minimum weight while considering the weight and size constraints imposed by the system designer as requirements. Initially, a mathematical model is developed and solved numerically, and the effect of design parameters on the performance of a panel radiator, including face and core thickness, spacing between heat pipes, mass, and surface area, is comprehensively investigated. Based on the simulation results, considering the weight limitations and existing face and core thicknesses, the maximum allowable spacing between heat pipes is calculated to achieve maximum efficiency of the panel radiator. A network of heat pipes with this characteristic was produced and used in the panel sandwich. The results obtained from testing the manufactured panel radiator were compared with the design efficiency to validate the model. Based on the experimental results, an efficiency of 89% was obtained at a root temperature of 39°C. The error of this efficiency with the efficiency calculated from the theory is about 3%.
Volume 25, Issue 2 (Spring 2022)
Abstract
Introduction: Emerging evidence suggests that lipoproteins levels are associated with cognitive health. This study examines the relationship between lipoprotein levels and cognitive performance in middle-aged and young adults. It addresses the impact of abnormal lipid levels and hypercholesterolemia on cognitive impairment.
Methods: We performed a cross-sectional study involving 123 healthy security guards aging 20- 60 years old. Lipid profiles included total cholesterol (TC), low-density lipoprotein, high-density lipoprotein (HDL) and triglyceride (TG) levels were measured in serum. EEG recording was used to obtain the cognitive indicators of attention, memory, salience, language, mood and executive function. Spearman correlation analysis was used to determine the correlation between lipoproteins and cognitive indices.
Results: A significant relationship with executive function was found for TC (r = -0.2944, p = 0.0202) and LDL (r = -0.3687, p = 0.0032). Additionally, a significant relationship was found between attention and serum HDL levels (r = -0.1987, p = 0.0296). In middle-aged security guards, there was a significant correlation between attention and TC (r = -0.4338, p = 0.0187) and LDL (r = -0.3909, p = 0.0360). Also, there was a significant correlation between executive function and TC (r = -0.5475, p = 0.0368) as well as LDL (r = -0.6709, p = 0.0077).
Conclusion: Our findings suggest that executive function and attention are key cognitive indices significantly linked to lipoproteins. In the middle-age group, higher TC and LDL levels correlated with lower cognitive scores compared to the general population, indicating a potential role of lipoprotein factors in cognition.
Methods: We performed a cross-sectional study involving 123 healthy security guards aging 20- 60 years old. Lipid profiles included total cholesterol (TC), low-density lipoprotein, high-density lipoprotein (HDL) and triglyceride (TG) levels were measured in serum. EEG recording was used to obtain the cognitive indicators of attention, memory, salience, language, mood and executive function. Spearman correlation analysis was used to determine the correlation between lipoproteins and cognitive indices.
Results: A significant relationship with executive function was found for TC (r = -0.2944, p = 0.0202) and LDL (r = -0.3687, p = 0.0032). Additionally, a significant relationship was found between attention and serum HDL levels (r = -0.1987, p = 0.0296). In middle-aged security guards, there was a significant correlation between attention and TC (r = -0.4338, p = 0.0187) and LDL (r = -0.3909, p = 0.0360). Also, there was a significant correlation between executive function and TC (r = -0.5475, p = 0.0368) as well as LDL (r = -0.6709, p = 0.0077).
Conclusion: Our findings suggest that executive function and attention are key cognitive indices significantly linked to lipoproteins. In the middle-age group, higher TC and LDL levels correlated with lower cognitive scores compared to the general population, indicating a potential role of lipoprotein factors in cognition.
Volume 26, Issue 3 (Fall 2022)
Abstract
South Khorasan Province has gone through rapid industrialization and urbanization processes in the last decades and is under increasing pressure from various environmental challenges such as water scarcity and intensification of pollution and ecosystem degradation. Therefore, the purpose of this study is to develop scenarios for the future state of the environment of South Khorasan province using LIPSOR, the French school of scenario building, and by the application of simple interaction matrix models and morphological analysis to systematically help the environmental management orientations. For this purpose, key variables were first introduced as the main drivers or actors shaping the future. SMIC PROB-EXPERT software package was used to explain the initial scenarios of the future environmental situation of the province. Then a set of scenarios including the most probable scenarios were identified using MORPHOL software. Also, due to a large number of scenarios, the framework of general scenarios was used to describe different axes and conditions. The results of the study of the five main drivers in the SMIC model led to the extraction of 10 initial scenarios. Then, morphological analysis with the MORPHOL model with three political, institutional-executive, and cultural domains produced 3125 possible and probable scenarios, each of which shows the probability of D5/D6/D1/D33/D29 propulsion, respectively. Finally, the analysis of 50 possible scenarios showed that scenario 11111 is the most probable scenario (276.41%), and scenarios 11112, 11113, and 21111 are with probabilities of 184.28, 122.85, and 115.17, respectively, which are five of its constituent variables mainly indicating the probability of occurrence of low (1) to moderate (2 and 3) in the scenarios. In general, the future environmental situation of South Khorasan province is in the situation of the third quarter called lack of discretion in the environment. To change the future and move towards a better future, paying attention to each of the influential variables will be the way forward and can be directed towards a quarter of the framework with at least one flourishing axis.
Volume 27, Issue 1 (Spring 2023)
Abstract
Among the various processes of land degradation, soil erosion is known as a major environmental problem that causes the loss of topsoil and nutrients, reduces fertility, and thus decreases in crop yield. Evaluating and preparing a risk map and estimating the lost economic value due to the loss of soil nutrients can provide the basis for rational planning to prevent and control wind erosion. The aim of this research is to estimate the economic consequences of wind erosion in the Hamoon wetland, which is considered as one of the centers of dust production in the Sistan plain. This research has been done in two stages; first, using the IRIFR model, which is an experimental model to estimate the intensity of wind erosion, an attempt has been made to investigate the erosion intensity, prepare a map of erosion classes (danger), as well as determine the amount of annual sediment production in Hamoon wetland. In the second stage and the economic discussion on the topic, in two parts and using the information obtained from the first stage, using two methods of risk assessment and alternative cost, to prepare a risk map, and the economic value lost due to the loss of the main nutritional elements of the soil action has been taken due to wind erosion in the proposed region. The findings show that Hamoon lagoon has five risk classes in which, the low-risk class has the largest area with 41.15 percent. In terms of economics, from the point of view of the risk map, the largest area of the wetland includes the intensity of risk with 59.93 percent in the very low class, 32.68 percent in the very high class, and 7.36 percent in other classes. The amount of lost economic value of the main soil elements due to wind erosion in the mentioned wetland is estimated to be 994 billion Rials.