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Showing 172 results for Abdollah
Volume 20, Issue 9 (September 2020)
Abstract
In the current study, shear compaction processing was used for the recycling of aluminum machining chips and direct converting of them to bulk parts. In this processing, machining chips are first loaded in a cylindrical chamber, then a rotating tool with a defined rotational speed and aligned axis with the chamber is placed on the chips, in the following, the temperature inside the chamber increases due to the friction. Then, the process continues until all chips are transformed into a bulk part. After producing the samples, properties such as density, porosity, microstructure, hardness, and wear of the recycled parts were examined. The results showed that there is a possibility of transforming aluminum chips into a completely bulk part without porosity, with a density of about 2.67g/cm3 and hardness of more than half of the base metal via shear compaction process. The amount of heat during the process leads to the consolidation of the chips and nucleation of new grains with dynamic recrystallization. Finally, a review of the total results and properties of the recycled samples showed that they could be used as a industrial part directly or after a secondary process.
Volume 20, Issue 143 (January 2023)
Abstract
Coffee Mix is one of the most popular instant drinks in the world, which is widely consumed. This product can cause nutritional problems due to the significant amount of sugar in the formulation. On the other hand, due to its beneficial properties, honey and ginger powder can be used in the instant coffee powder formula, to solve the anti-nutritional effects of sugar and to take advantage of the beneficial properties of ginger and honey powder. In this study, the effect of adding honey powder as a substitute for sugar in amounts of 0, 5, 10, 20, 30, and 35% of the consumed sugar and ginger powder in amounts of 0, 0.05, 0.1, 0.2, and 3 0.0 and 0.35% were added to the 3 in 1 instant coffee formulation and the physicochemical properties, phenolic compounds, antioxidant capacity and sensory properties and microbial properties of the coffee mixture were evaluated. The research results showed that adding honey and ginger powder to the instant coffee mixture improves its physicochemical properties and overall acceptability. Sensory tests conducted by the evaluators also determined that the treatment of 20% honey powder and 0.2% ginger and the treatment of 10% honey powder and 0.3% ginger were more favorable samples in terms of overall acceptability. The treatment of 30% honey powder and 0.3% ginger had the highest amount of phenolic compounds and antioxidant capacity. Therefore, the most appropriate treatment in terms of nutritional characteristics was the treatment of 30% honey powder and 0.3% ginger.
Volume 20, Issue 145 (March 2024)
Abstract
In Iran, there is a large capacity for animal fat production, which is less used in food products. In this study, the fat obtained from sheep tail and ostrich abdominal tissue were investigated as waste from the slaughterhouse. For this purpose, in the first step, fats were extracted by wet rendering method and their chemical compositions were analyzed. In the second step, the fat was separated into two parts, stearin and olein, by dry fractionation. Then, the olein fraction was divided into two parts, soft stearin and superolein, and their fatty acid composition and physicochemical properties were measured. The sheep tail and ostrich tissues contained 10.66% and 5.18% moisture, 4.10% and 4.29% protein, 0.26% and 0.62% ash, and 84.93% and 88.35% fat, respectively, and the extraction yield were obtained 37.42% and 62.56%, respectively. The gas chromatography results showed that oleic acid, palmitic acid and stearic acid were the main fatty acids in sheep tail fat and oleic acid, palmitic acid, palmitoleic acid and linoleic acid were dominant in the fatty acid profile of ostrich fat. After fractionation, an increase in oleic content of olein and superolein in both fats increased iodine value and refractive index followed by decreasing melting point and L*. Peroxide value of sheep tail fat was 1.54 meqO2/ kg and the fractionation process had no significant effect on it, however, the peroxide value of ostrich fat increased significantly after the separation (p<0.05), which could be due to the presence of a considerable portion of linoleic in this fat. Therefore, it can be concluded that the fat extracted by wet rendering from sheep tail and ostrich tissues has an acceptable quality for edible use, and their stearin and soft stearin fractions can be used as an alternative to the hydrogenation process to produce semi-solid fat in food products.
Volume 21, Issue 1 (3-2021)
Abstract
A large main shock may consist of numerous aftershocks with a short period. The aftershocks induced by a large main shock can cause the collapse of a structure that has been already damaged by the preceding main shock. These aftershocks are important factors in structural damages. Furthermore, despite what is often assumed in seismic design codes, earthquakes do not usually occur as a single event, but as a series of strong aftershocks and even fore shocks. In other word, structures that are located in seismically active regions often may be subjected to successive earthquakes which occurred with significant PGA in a short time after each other. For this reason, this paper investigates the effect and potential of consecutive earthquakes on the response and behavior of reinforced concrete structures. For this purpose, the response modification factor (R factor) which is one of the significant parameters in the structural design of buildings and decreases the lateral forces induced by earthquakes, is calculated and estimated for reinforced concrete moment frames under critical single and successive earthquakes. Thus, three reinforced concrete moment frames with 5, 7, and 12 stories are designed according to Iranian seismic codes (standard No. 2800) and modeled in Opensees software. After the design of the samples, critical seismic scenarios with/without successive shocks are selected from “PEER” center. Consecutive earthquakes not only occurred in the similar directions and same stations, but also their real time gaps between successive shocks are less than 10 days. In the following, R factors of RC moment frames are calculated from the results of incremental dynamic analysis (IDA(, time history and nonlinear static analysis (pushover). The results show about 20% reduction in the R factor and, also increment of damages under successive earthquakes comparing to the individual one. Finally, the idealized multilayer artificial neural networks, with the least value of Mean Square Error (MSE) and maximum value of regression (R) between outputs and targets were then employed to estimate the R factors. Theses artificial neural networks are designed based on the features of frame properties, successive earthquakes. Comparison of predicted R factors with real values indicates the adequate ability of networks in estimation of the results. So that, the average error for the artificial neural network model for predicting the calculated results from IDA, Pushover and Linear Analysis is less than 4%. To be more specific, more than 73% and 93% of the simulated R factors are within ±5% and ±10% of the real values for artificial neural network model. This is an indication that the networks have learned to generalize the unseen information well and reflects good precision in simulating. Moreover, it can be seen that the values simulated by the artificial neural network model spread around the 45 degree line which implies neither over-estimation nor under-estimation.
Volume 21, Issue 2 (10-2015)
Abstract
Art has not been extensively discussed in the Islamic tradition, except a few instances in the Islamic Jurisprudence. There is no discussion of the essence or definition of art in Islamic scholarly spheres, including philosophical spheres. One can find nothing comparable to the philosophy of art as found in the Western philosophy, especially after the Eighteenth century, in the philosophical or mystical works of Muslim scholars, except a few references to similar discussions in the Islamic mystical works as part of their larger discussions on Futuwwat-namahs or on light. However, there are extensive discussions on beauty in Islamic scholarly literature. Most philosophers have mentioned beauty as part of their discussion on existence. Some mystics also after discussing the beauty of God, have discussed about beauty in itself, expounding such terms as jama`l, husn, malaha, and so forth.Therefore, beauty and art in the Islamic tradition have to be discussed independently, and not in the framework of Western philosophy. What we have in Islamic tradition is aesthetics in its non-sensible kind. We have to avoid imposing Western philosophy on Islamic philosophy. Searching for common terms is not the right way for finding an Islamic philosophical system compatible to the Western philosophical system, relevant to the art that has developed in the context of Islamic culture and civilization.
Volume 21, Issue 3 (12-2017)
Abstract
Increasing expansion of competition among commercial companies and variations relate to increase or decrease in the market share, brings a scientific look at all marketing functions forward. One of the most important marketing activities is attention to why and how customers' behaviors are created. The present research's objective is to determine effects of the brand's social power base on the purchase behavior mediated by level of consumerProduct involvement. Statistical society of the research includes costumers of Iran-Khodro company agencies in khorramabad city. Due to infinite volume of statistical population, a sample of 384 subjects were chosen using Cochran formula and available sampling method. validity and reliability of the questionnaire were confirmed using content-creditability method and cronbach-alfa respectively. To examine and test hypotheses, the structural equation modeling approach and Amos software were used. The research finding indicate that at %5 error level , the bases of the brand's social power have a significant positive effect on the purchase behavior and cognitive engagements of the consumers product. In addition, it can be stated that at the error level of %5, the product's cognitive engagement has a mediator role in the effects of the brand's social power bases on the purchase behavior.
Volume 21, Issue 5 (May 2021)
Abstract
Supplementary firing system is one of the common methods of increasing the power generated of combined cycle units. Low cost of investment to the rate of increase of the generative power has encouraged the designers to use this method in the above power plants. In this article, field study of the performance changes of a real combined cycle unit with and without supplementary firing has been performed from energy and exergy viewpoints. Studies show that in all operation modes subject to research, using supplementary firing causes an increase in power generation up to 26.3MW, energy efficiency of steam cycle about 2.43% and decreases the exergy destruction of steam flow control valves. But this system has a negative impact on energy and exergy efficiencies of the whole combined cycle, which at the worth case about 1.17% decreases energy efficiency. In addition, it was specified that the power plants operation in the partial loads causes high exergy destruction in the cycle which steam cycle increased energy and exergy efficiencies due to use supplementary firing system cannot fully compensate it.
Volume 21, Issue 146 (April 2024)
Abstract
Ber fruit (Zizyphus mauritiana Lamk) contains abundant polyphenols and is highly susceptible to enzymatic browning after harvest. In order to reduce browning and maintain fruit quality of ber fruit, a factorial experiment was conducted in a completely randomized design with four replications. Experimental treatments included Aloe vera gel-based (20%) edible coating enriched with sesame oil 1%, honey 1% (ASH) and Zataria multiflora Boiss essential oil (ZEO) (0, 0.5 and 1%) and storage time (0, 7, 14, 21 and 28 days) at 6 ± 1°C and relative humidity of 90±5%. The results showed that edible coating application had significant effect on the quality characteristics of the ber fruit during storage. The combination of ASH with ZEO (0.5%), as an edible coating, significantly alleviated enzymatic browning by reducing PPO and POD activities on fruit during 28 days of storage. Fruits treated with ASH with ZEO (0.5%) reduced browning index (70%) compared to the control; while increased total phenol content and antioxidant activity (18.14%, and 31.16%, respectively) compared to the control after 28 days of storage. Also, ASH in combination with ZEO (0.5%) treatment decreased electrolyte leakage and malondialdehyde (19.7%, and 17.8%, respectively) compared to the control after 28 days of storage. These results indicated that ASH edible coating in combination with ZEO (0.5%) can be a useful method for delaying ripening and senescence, extending the storage life of ber fruit.
Volume 21, Issue 149 (July 2024)
Abstract
In current study, whey powder, guar and tragacanth gums were used at the different levels of 0.1, 0.3 and 0.5%, and in a mixed forms of 0.25% whey powder and 0.25%. Guar gum, 0.25% of whey powder and 0.25% of tragacanth gum in the formulation of Sangak bread to improve farinographic and extensograph properties of dough and physicochemical and sensory properties of bread. The results showed that the highest water absorption and dough development time and the lowest weight loss and firmness were observed in the sample containing 0.5% tragacanth gum. The samples containing guar gum and tragacanth and the sample containing 0.25% whey powder and 0.25% guar gum had the longest dough stability time. Tragacanth gum had the greatest role in reducing the degree of softening and increasing the farinograph quality number. Guar gum was more effective than other ingredients in improving dough extensibility. The effect of tragacanth gum and guar on dough resistance was increasing and decreasing, respectively. The highest energy was observed in the sample containing 0.25% whey powder and 0.25% tragacanth gum. The additives used improved the odor, color and chewability of Sangak bread. Thus, the sample containing 0.5% tragacanth gum (1 priority) and the sample containing 0.25% whey powder and 0.25% tragacanth gum (2 priority) has been introduced as the best samples.
Volume 22, Issue 1 (1-2020)
Abstract
Retrotransposons (RTNs) are a major source of genomic changes in plant genomes and, therefore, are extensively used as ideal molecular markers for genetic variability, DNA fingerprinting, and genetic mapping studies in plant species. In the present study, two RTN-based marker systems, inter-retrotransposon amplified polymorphisms (IRAPs), and the retrotransposon-microsatellite amplified polymorphisms (REMAPs) were used to assess genetic variability and structure in a collection of 94 durum wheat genotypes. In general, 63 and 141 loci were amplified using 6 IRAP and 15 REMAP primers, respectively. Percentage of polymorphic loci (PPL) in the studied collection for IRAP and REMAP markers were 47.15% and 47.81%, respectively. The average of expected heterozygosity (He), number of effective alleles (Ne), and Shannon's information index (I), separately estimated based on IRAP and REMAP data, were not considerably different. A model-based Bayesian method and cluster analysis using Neighbor joining (NJ) algorithm depicted five clusters. A moderate level of inter-group genetic variability was detected among the clusters (11%) obtained from STRUCTUR software (PhiPT =0.111; P=0.001) with the vast majority of variation (89%) still uncaptured within groups. Most of the accessions and landraces from Iran aggregated together in clusters I and III with the cultivars from Turkey. Also, Iranian and foreign durum wheat landraces were assigned to different clusters or subpopulations in both clustering methods. In conclusion, the results showed that the genetic diversity of Iranian durum wheat is low and it is necessary to extend the genetic base of durum wheat germplasm in Iran.
Volume 22, Issue 2 (9-2018)
Abstract
Electronic Businesses have an undeniable role in growth of country’s economy. Although different researches and studies show that using email marketing in electronic businesses is too important, but there are many problems and challenges about content, time, process of sending email and etc. So research about this subject is valuable and important.
For answering the questions of this research, first the definitions about this subject is determined and then the requirements for email marketing implementation is explained.
This research is practical and it will be beneficial to marketers and businesses who wants to implement email marketing. This research is answering the question “For implementing and deploying email marketing what actions to take and what requirements is needed”.
The statistical sample of this research is email marketing experts who is working for E-businesses and required information has been obtained by questionnaire. LISREL software for data analysis and confirmatory factor analysis was used.
The final results of this study show that the framework of email marketing within the three dimensions of technology, people and processes, and it also will help to marketing managers of companies or small and medium enterprises owners.
Volume 22, Issue 3 (March 2022)
Abstract
The design and optimization of multiple production systems, including systems that simultaneously generate heat, power and freshwater, play an important role in improving the performance of these systems. In this study, after modeling a multi-effect evaporative desalination system MED and simultaneous heat and power generation CHP, they are combined to meet the demand for heating, power and fresh water for a hotel. The purpose of this study is the thermoeconomic evaluation of the use of thermal energy storage TES tank in the combined system CHP + MED compared to the non-use of this tank. The strategy is applied every 24 hours of the two seasons. In optimizing this system, the annual cost minimization has been done as a objective function and using genetic algorithm. Optimal technical results in these systems show that the system CHP + MED + TES requires a gas turbine with a nominal capacity of 12% larger and a backup boiler with a nominal capacity of 7.14% smaller than the system CHP + MED. The optimal results of the economic comparison show that by using the thermal energy storage tank in the combined system CHP + MED, the annual cost is improved by 4.91%.
Volume 22, Issue 4 (6-2020)
Abstract
To extend the genetic base of Iranian tomato germplasm, 93 landraces were collected from the northwest of Iran and East Anatolian of Turkey, along with three commercial cultivars, and their genetic structure were studied using 39 SSR primers. Thirty-five polymorphic SSR loci generated a total of 118 alleles in the studied germplasm. Number of alleles per locus and effective number of alleles averaged 3.37 and 2.47, respectively. Expected heterozygosity of SSRs varied from 0.227 (TMS24) to 0.773 (LEta016), averaged 0.558. The mean number of alleles per genomic-SSRs (3.61) was more than that of EST-SSRs (2.66). Cluster analysis using Neighbour Joining (NJ) method placed 96 tomato genotypes in eight groups. Little congruence was found between NJ dendrogram and geographical distances. Genetic structure analysis of the germplasm using Bayesian method revealed two sub-populations and separated cherry tomatoes from the other landraces and commercial cultivars. Out of the 21 morphological characters, significant (P≤ 0.05) marker-trait associations were found for 18 characters. Each of SSR loci TC11, TC948, and Tom236-237 was associated with three characters. The genetic variability, structure, and markers associated with the studied traits in the current study can be used for planning tomato breeding programs and future studies.
Volume 23, Issue 1 (3-2023)
Abstract
Recycling of concrete has been the focus of researchers owing to the large volume of concrete waste and the limited resources of valuable materials. Recycled aggregate concrete (RAC) contains aggregates of various types of concrete and building materials that have been destroyed due to their shelf life or as a result of war and natural disasters. In order to use different types of recycled aggregates (RA), it is necessary to conduct more detailed and sensitive research on the behavior of RAC in order to reach the highest possible level of quality and cost in the construction process. On the other hand, RA are made of concrete with different properties and its aggregates have been subjected to different form of loading, hence it is important to carefully examine their behavior and properties. Therefore, in this study, the strength and the durability of RAC after freeze and thaw cycles were compared with natural concrete while different water/cement ratios are used.
In this study, RA were extracted from demolished waste concrete specimens and used to produce three mixtures named RC, RN and NC while 100, 50 and 0 percent of RA were replaced respectively. Water to cement ratio were kept as 45 and 55 percent of cement. A total number of 57 samples for flexural, compressive, tensile strength and ultrasonic tests were made. 24 samples were placed in the refrigerator and freeze and thaw cycles were applied on. 18 and 15 specimens were prepared for testing at 28 and 120 days of age, respectively. According to ASTM C666, the relative dynamic modulus of the specimens was tested using ultrasonic test after each 40 cycle’s period. After the test was finished, compressive strength, single point bending, indirect tensile tests and elastic modulus were determined for each specimens. Finally, the behavior of recycled and natural concrete was compared.
The results showed that the freeze and thaw cycles reduced the resistance of both RAC and NAC. Recycled aggregates have 2.5 times more water absorption than Natural aggregates. RAC has lost 41%, 18%, 10% and 28% of its compressive, flexural, tensile strength and modulus of elasticity, after the freeze and thaw cycle, respectively. The 100% replacement of RA reduced even more the mechanical behavior of samples. The relative dynamic modulus at the end of the cycles for RAC was 2% higher than that of NAC, indicating its better durability properties against freeze and thaw cycles. Concrete with 50% replacement of recycled aggregate has almost the same durability and strength as NAC, hence is recommended to be use in similar condition
Volume 23, Issue 3 (5-2021)
Abstract
Continuous Biological Control (BC) of pests can reduce unnecessary pesticide applications in rice production, thus promoting occupational safety and health in farming. In this study, the Transtheoretical Model (TTM) of behavior change was examined for its applicability in explaining adoption and maintenance of BC use among 344 rice farmers of Simorgh County, Mazandaran Province in northern Iran, to better understand how farmers change their pest management behavior for incorporating BC. The stages of behavior change in BC use were assessed according to the TTM model, i.e. Pre-Contemplation (PC), Contemplation (C), Preparation (PR), Action (A), and Maintenance (M), in the management of rice stem borer [Chilo suppressalis (Walker)]. Almost three quarters (75.1%) of the farmers were in pre-action stages (43.1% in PC stage, 16.3% in C stage, and 15.7% in PR stage), 15.1% were changing their behavior (A stage), and while few farmers (9.8%) reported continuous use of BC agents for more than two cropping seasons (M stage). Farmers in the early stages of TTM model showed lower education levels, higher income, lower self-consumption of rice, higher grain yields, higher damage by rice stem borer, and lower knowledge levels about natural enemies than those who were in the later stages of change. Moreover, self-efficacy in BC use and perceived advantages of BC use increased through the stages of change, whereas the perceived disadvantages of BC use decreased. This is the first report supporting the appropriateness of the TTM in explaining farmers’ behavior change in BC use, which provides novel evidence on farmers’ adoption process of BC. Extension measures should focus on usual obstacles related to BC use, such as perceived advantages and disadvantages of BC as well as self-efficacy in BC use, targeting to match the stage of change with various intervention strategies.
Volume 23, Issue 3 (8-2023)
Abstract
Abstract
Wharf is an engineering structure which is constructed generally for loading or unloading of goods. The structure may be constructed on the weak layers like gravel and sand with respect to the bank conditions. In case of incorrect design of this type of structure and its failure, the wharf activities may be stopped for a long time due to damage to adjacent facilities. For this reason, investigating the behavior of coastal structures against failure factors such as earthquake and the liquefaction due to it, is of great importance. Analysis of wharf performance against liquefaction is done generally using the numerical methods. In this article using the Flac2D software which has the capability of nonlinear analysis of effective stress and generation of excess pore water pressure in the soil continuum, the liquefaction phenomenon in the soil surrounding the wharf is simulated using the behavioral model Finn. In continuation, the impact of different earthquake parameters on the wharf behavior is investigated. Finally, the results of the excess pore water pressure, horizontal displacement, soil settlement and bending moment of piles are presented. Then, the correlation between these parameters and different earthquake parameters is investigated. As the earthquake intensity criteria have great importance in terms of statistical assessment of seismic demand of various types of structures, therefore, in this study in order to investigate the quality of earthquake intensity criteria, the determining indices such as being optimal and applicable, efficiency index, sufficiency with respect to the earthquake magnitude and distance to the center of earthquake propagation are investigated. The results show that compatibility between the earthquake parameters and soil settlement is generally better with respect to other parameters.
Keywords: Wharf, liquefaction, dynamic analysis, finite difference method.
Volume 23, Issue 6 (June 2023)
Abstract
The type and material of the core piece of sandwich panels are important parameters in the mechanical behavior of these sandwich samples. In this study, the mechanical behavior of sandwich panels with two types of aluminum alloy foam core was investigated. Also, the effect of the method used to stabilize aluminum foam investigates and compares during the bending and compressive tests, for this purpose, the properties of the core of sandwich panels made with LM13 alloy aluminum foam were fabricated with calcium stabilizer and silicon carbide powder separately. The results of the X-ray diffraction test showed the presence of Al4Ca intermetallic compounds in aluminum foams containing calcium metal, and silicon carbide particles for aluminum foams containing silicon carbide powder in the cell wall. The yield strength of sandwich panels with aluminum foam core and calcium metal stabilizer was higher than that of cores with silicon carbide particle stabilizer. Also, sandwich panels with aluminum foam cores containing silicon carbide powder showed more energy absorption. In contrast, foams with silicon carbide powder stabilizer absorbed more energy under the uniaxial pressure test. Also, the results of the macrostructure analysis of how the shape of the sandwich panel changed in the three-point bending test were indicative of a reduction in force due to the weakness in the connection between the sandwich panel shell and the aluminum foam core.
Volume 24, Issue 1 (Spring 2020)
Abstract
Introduction
Population growth and migrationof (from or to) cities has led to the construction of unstructured and large changes in the spatial structure and expansion of cities. This causes changes in the surface of the earth and the conversion of natural effects of the earth such as soil and vegetation to the urban texture. So, the first consequence of the expansion of cities is land use change. Today, land use change and land cover have become a major challenge in many countries. Hence, the study of these changes plays a major role in the world's environmental studies. In order to better manage natural and human ecosystems and develop long-term planning, it is necessary to model land use changes and predict future changes.
Methodology
The research method is applied in terms of purpose and the nature and method of descriptive-analytic research, and the method of data collection in this study is also a library research. In this study, for land use changes during the 29-year period, images were first provided from the website of the Geological Survey of the United States. Then, using ENVI software, the pre-processing operation was performed to apply atmospheric and radiometric corrections. Also, the specimens of educational and supervised classification of images for land use in four levels (lands, rice field, forests, gardens and Water zone) were studied. Then, in the IDRISI SELVA software, simulation was used to predict future changes using the perceptron neural network.
Results and Discussion
Before the main analysis of the data and the extraction of the information, it is necessary to perform the pre-processing operation. Then several time satellite images used in the research after atmospheric and radiometric corrections were used to prepare the land use map and Maximum likelihood algorithm was used to classify the desired classes. The selection of effective variables in predicting urban growth is an important and useful information for the user to understand the desirability of land use change. Therefore, in the present study, distance variables from the road are considered as independent static variables, and distance from the landfill, distance from the land, and the distance from the forest and gardens are considered as independent variableswere used. Among the models that are used in the simulation of land use change, neural networks are multilayered perceptron. Therefore, this model was used to simulate land use changes in this study. Finally, according to the Kramer coefficient, the distance from the road has the least effect and the distance variable of the land has the greatest impact on land use change and transmission potential modeling. Then, user-potential mapping maps were generated through multi-layer perceptron neural networks for an 8-year time span. Also, in the maps produced, regions with a warm color spectrum have the greatest potential for change, and are more vulnerable to areas with a cool color spectrum.
Conclusion
Today, land use change and land cover have become a major challenge in many countries. These changes have a direct impact on environmental components such as soil, water and atmosphere.Which This causes changes in the surface of the earth and the conversion of natural effects of the earth such as soil and vegetation to the urban texture. Due to the fact that the city of Lahijan, like many other cities in Iran, has faced expansion of construction in recent years, so, today, the city has undergone significant changes in land use. The purpose of this study is to model and predict land use changes using the Multilayer Perceptron, . In this regard, in order to implement this model, Landsat classified satellite images for the four periods of 1989, 2000, 2010 and 2018, as well as four independent variables including distance from the road, distance from Shalizar, distance from the forest and gardens, And and distance from the land, were built to simulate land use changes. The study resulted in the generation of transmission potential mapping with the 84.58 accuracy index, which shows that the distance from the land constructed the greatest impact and the distance from the road has the least effect on land use change variations.
Population growth and migration
Methodology
The research method is applied in terms of purpose and the nature and method of descriptive-analytic research, and the method of data collection in this study is also a library research. In this study, for land use changes during the 29-year period, images were first provided from the website of the Geological Survey of the United States. Then, using ENVI software, the pre-processing operation was performed to apply atmospheric and radiometric corrections. Also, the specimens of educational and supervised classification of images for land use in four levels (lands, rice field, forests, gardens and Water zone) were studied. Then, in the IDRISI SELVA software, simulation was used to predict future changes using the perceptron neural network.
Results and Discussion
Before the main analysis of the data and the extraction of the information, it is necessary to perform the pre-processing operation. Then several time satellite images used in the research after atmospheric and radiometric corrections were used to prepare the land use map and Maximum likelihood algorithm was used to classify the desired classes. The selection of effective variables in predicting urban growth is an important and useful information for the user to understand the desirability of land use change. Therefore, in the present study, distance variables from the road are considered as independent static variables, and distance from the landfill, distance from the land, and the distance from the forest and gardens are considered as independent variables
Conclusion
Today, land use change and land cover have become a major challenge in many countries. These changes have a direct impact on environmental components such as soil, water and atmosphere.
Volume 24, Issue 2 (6-2024)
Abstract
Human civilizations have always depended on freshwater to form, develop and fulfillment of various needs. With increasing urbanization, not only has the need for freshwater not diminished, but also some new technologies and industries have increased water consumption, and the pollution of water sources has increased significantly. Since groundwater resources are far from surface pollution and have their natural remediation ability, protection and remediation have not been given sufficient and appropriate attention. This issue and the overexploitation of aquifers have resulted in the quantitative and qualitative balance of groundwater resources being unsustainable. These issues show that further research is needed on various aspects of groundwater remediation. By developing the equations for water movement in porous media and analyzing them, it is possible to simulate groundwater flow. In this study, the double-well pumping system has been investigated analytically as one of the effective methods for aquifer remediation. In this system, pumping wells provide a return to natural conditions by draining polluted water and preventing it from spreading in the aquifer. For this purpose, the equations of the groundwater potential function and the stream function were determined for two pumping wells near a permanent stream. In other words, the real part of the complex potential equation represents the potential function and its imaginary part specifies the stream function; using the image well theory, the effect of the stream was also applied in the problem relations. By determining the coordinates of the stagnation points, the capture zone of the multi-well system was delineated in various configurations and the amount of stream withdrawal was also calculated. The capture zone describes the behavior and capability of the multi-well system by indicating the capture domain of discharge wells for different distances and different pumping rates. Three configurations of the remediation system are presented for two types of critical pumping rates. Under these conditions, it is possible to control the capture zone without intercepting the stream boundary and creating gaps in the extraction region at different distances of the wells with certain pumping rates. At the first critical pumping rate, the capture zone of the double-well system is tangent to the permanent stream boundary, and at a pumping rate below this threshold, groundwater pollution does not reach the surface waters. At the second critical pumping rate, capture zones of two wells merge together. Indeed, in discharges less than this critical rate, there is a distance (gap) between capture zones of the wells and pollution can enter the surface water through this gap. Also, the distance between two wells was determined in the state that both types of critical pumping rate are equal. This case shows a state of capture zone whose boundary is tangent to the stream boundary, and the capture zones of two wells are merged together. In the mentioned state, the dimensionless distance between two pumping wells (the distance between the two wells divided by their distance from the stream boundary) and the dimensionless critical pumping rate are equal to 2×0.58 and 0.33, respectively.
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%.