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Volume 2, Issue 3 (9-2013)
Abstract
Life table gives the most comprehensive explanation of the survivorship, development, and reproduction of a population. The life table parameters of an aphidophagous midge, Aphidoletes aphidimyza were studied on different densities (5, 10, 20, 40, 60, 80) of third instar nymphs of Aphis gossypii as prey in a growth chamber (25 ± 1 °C, 70 ± 5% RH and a photoperiod of 16L: 8D h). The pre-ovipositional period of female A. aphidimyza was reduced as prey density increased with no significant difference. The oviposition period was 3.833 ± 0.401 and 5.5 ± 0.463 days in lowest and highest prey density, respectively. Fecundity increased significantly with increasing prey density. The lowest fecundity was obtained at density of 5 preys/day (49.667 ± 6.053 eggs) and the highest was at density of 80 preys/day (104.25 ± 7.78 eggs). Intrinsic rate of increase (rm) ranged from 0.110 ± 0.016 to 0.166 ± 0.014 d-1 with increasing prey density. Net reproductive rate (R0) was positively dependent on prey density. The peak reproductive values showed that female aphidophagous midge at ages of 17, 18, 19, 22 and 25 days made the highest contribution to the population when reared on 5 to 80 preys in a day, respectively. However, mean generation time (T) ranged from 22.42 ± 0.55 to 24.47 ± 1.04 days. It was concluded that the increase in the density of third instar nymphs of A. gossypii significantly affected the demographic parameters of A. aphidimyza and it had a better reproductive performance in higher prey densities.
Volume 8, Issue 1 (1-2019)
Abstract
Understanding the spatial dynamics of insect distributions provides useful information about their ecological requirements and can also be used in site-specific pest management programs. Interactions between prey and predator are spatially and temporally dynamic and can be affected by several factors. In this study, geostatistics was used to characterize the spatial variability of spotted alfalfa aphid, Therioaphis maculata Buckton and coccinellid lady beetles in alfalfa fields. Global positioning and geographic information systems were used for spatial sampling and mapping the distribution pattern of these insects. This study was conducted in three alfalfa fields with areas of 7.3, 3.1 and 0.5 ha and two growing seasons, 2013 and 2014. The 0.5 ha field was divided into 10 × 10m grids and 3.1 and 7.3 ha fields were divided into 30 × 30m grids. Weekly sampling began when height of alfalfa plants reached about 15cm and was continued until the cuttings of alfalfa hay. For sampling, 40 and 10 stems were chosen randomly in 30 × 30m and 10 × 10m grids, respectively and shaken into a white pan three times. Aphids and coccinellids fallen in the pan were counted and recorded. Semivariance analysis indicated that distribution of T. maculata and coccinellids was aggregated in the fields. Comparison of the distribution maps of aphid and lady beetles indicated that there was an overlap between the maps, but they did not coincide completely. This study revealed that relationship between spotted alfalfa aphid and lady beetles was spatially dynamic. These results can be used in biological control and site-specific management programs of T. maculata.
Volume 9, Issue 1 (12-2020)
Abstract
In this study, the effect of three temperatures was investigated on the functional response of Orius laevigatus to Aphis gossypii in climatic chambers at 20, 25, and 30 ± 1 °C, 60 ± 5% RH, and 16:8 h photoperiod. Different densities of first and second instar nymphs of A. gossypii (2, 4, 8, 16, 32, and 64) on cucumber leaf discs (6 cm in diameter) were separately offered to male and female predators. After 24 h, the number of consumed preys was recorded. Ten replicates per each aphid density were used. Based on the results, predator male and female exhibited types II, III, II and III, II, III functional responses at 20, 25 and 30 °C, respectively. Handling times (Th) for males were 0.7798, 0.9177 and 0.4476 h and for females were 0.6874, 0.3921 and 0.2831 h at 20, 25 and 30 °C, respectively. Using the indicator variable method, pairwise comparisons of handling times of both males and females were significantly different. The theoretical maximum predation rate (T/Th) of both males and females were obtained at 30 °C. The results revealed that O. laevigatus is more likely to be an effective biocontrol agent of A. gossypii at higher temperatures around 30 °C. However, additional studies under natural conditions are needed to provide further details of the predator-prey interactions.
Volume 9, Issue 37 (3-2021)
Abstract
Understanding "myth" is very important in understanding society, people's behaviors, and beliefs. We know that myth usually changes throughout history, but it disappears gradually. "The Story of Fereydoun" is considered as one of the most important stories of Iranian myths and researchers have traced its mythological roots to the Avestan period, Vedic texts, and the myths of birth and battle of the demon of land. The god of rain is mentioned in this story as well. On the other hand, there are myths and stories among people that contain mythical themes, symbols and signs in various forms, and the study and analysis of these myths in tracing the origins of the mythical elements of society plays an important role. One of these popular stories is "The Story of Shahzid", one of the Imamzadehs of Amol city of Mazandaran, which has many similarities with the story of Fereydoun in its narrative structure, semiotic elements, and mythical symbols. In this article, these two stories are examined and analyzed together, and their mythological elements are identified. It was concluded that the two stories, there are some similarities in some events and symbols of the myths such as: cow, tree, forest, snake, healing drink, witchcraft and geographical location. Both stories originate from a source which is the "myth of birth" and the war between the god of rain and the demon of land.
Introduction
Some studies have been done on the mythical story of Fereydoun and its comparison with mythology, but they are not comparative with regards to a story from the post-Islamic period and Islamic myths.
The main question of the research is whether a connection can be found between the story of the myth of Fereydoun and the story of Imamzadeh Shahzid. Could this connection be based on a myth?
In addition to Shahnameh's narration of Fereydoun's story, the summary narration of the people of Mazandaran is that: Fereydoun's mother hides him in the forest in a crack of an old tree when he is born. Every day, the cow goes near the tree and Fereydoun, the child, drinks milk from the cow. The owner of the cow notices and takes the child with him. "The cow loved Fereydoun and allowed Fereydoun to ride him."
Zayd ibn Musa ibn Ja'far is one of the Imamzadehs of Amol. Imamzadeh, fleeing from the enemies to the south of Amol, takes refuge in an old tree in a mountainous and forested area. The cow is commanded by God to go to the tree every day so that the gentleman can milk it. Galesh notices and strikes him with an ax and runs away. The prince curses Galesh and the ranch is stoned with all the cows. The Galesh family is also displaced. According to the story, the prince was a four-year-old child.
It is said that the servant of Astana Shahzid seeks water on the way during prayers to perform ablutions. At the same time, a pitcher and rosary descends on him from the sky. Saif performs ablution from the water of the pitcher and prays next to the rosary. The pitcher disappears, but the rosary is removed safely, and whenever the disease comes, the rosary is put in some water and the rosary water is drunk by the patient. According to the villagers, there are two green snakes with a cockatiel on the guard of Shahzid threshold, its spring, atmosphere, and water reservoir.
Mythical elements
Cow: Cow has been one of the ritual animals in ancient Iran. In the story of Fereydoun and Shahid, the main point is milking a cow, which goes back to the "mother goddess" of cows and raising humans. Since the prince emerges from the crack of the tree, it can be a symbol of the womb that is associated with the tree as the mother goddess. Cow is also closely related to rain and water in mythology. The myth of the god of clouds and rain can be deduced from it according to the myth of Indra and Trita Aptie.
In Dinkard, Fereydoun turns the Mazandaranis into stones. At the command of Ormazd, he firmly binds Zahak like a stone in a cave and achieves happiness and kingship, and the Imamzadeh of Shahzid stones the cattle ranch and cows.
The village of Shahzid is located on the border between the forest and the mountains without trees. In other words, the rainy clouds of the north remain behind the Alborz mountains in this region and collide with each other.
Forest and tree: "In mythology, the forest is a psychological realm having a feminine origin, the place of examination and knowing the unknown dangers and darkness, and the entry to the dark or symbolic haunted area" (Cooper, 2013, p. 110). The relation of forest with fertility, rain, and water could be another confirmation of the main roots of the myths in these two stories.
Snake: "Snakes guard the thresholds and temples, and all the gods depend on them. The two snakes represent the contradictions in the duality that eventually lead to unity" (ibid., p. 349). In the story of Fereydoun, a snake has grown on Zahak and makes him a demonic creature. "According to a version, Fereydoun was a three-headed snake that overcame another three-headed snake, namely Zahak" (Shamisa, 2015, p. 261).
Some scholars consider the word Fereydoun to mean having three spiritual, physical, and medical powers. These three attributes can be found to some extent in Imamzadeh Shahzid: having the spirit of a fighter and purity, being a master and fighting enemies, the symbolic tool of iron with changes in the Galesh's ax, the rosary's medical potentiality and the healing power of the water, and the magical ability in stoning cattle.
The title of Shah, which is used in the Iranian culture for Imams, their sons, and the Sufi followers is remarkable so far as the mythological semiotics is concerned, and it can be analyzed with regards to the story of Fereydoun.
References
Introduction
Some studies have been done on the mythical story of Fereydoun and its comparison with mythology, but they are not comparative with regards to a story from the post-Islamic period and Islamic myths.
The main question of the research is whether a connection can be found between the story of the myth of Fereydoun and the story of Imamzadeh Shahzid. Could this connection be based on a myth?
In addition to Shahnameh's narration of Fereydoun's story, the summary narration of the people of Mazandaran is that: Fereydoun's mother hides him in the forest in a crack of an old tree when he is born. Every day, the cow goes near the tree and Fereydoun, the child, drinks milk from the cow. The owner of the cow notices and takes the child with him. "The cow loved Fereydoun and allowed Fereydoun to ride him."
Zayd ibn Musa ibn Ja'far is one of the Imamzadehs of Amol. Imamzadeh, fleeing from the enemies to the south of Amol, takes refuge in an old tree in a mountainous and forested area. The cow is commanded by God to go to the tree every day so that the gentleman can milk it. Galesh notices and strikes him with an ax and runs away. The prince curses Galesh and the ranch is stoned with all the cows. The Galesh family is also displaced. According to the story, the prince was a four-year-old child.
It is said that the servant of Astana Shahzid seeks water on the way during prayers to perform ablutions. At the same time, a pitcher and rosary descends on him from the sky. Saif performs ablution from the water of the pitcher and prays next to the rosary. The pitcher disappears, but the rosary is removed safely, and whenever the disease comes, the rosary is put in some water and the rosary water is drunk by the patient. According to the villagers, there are two green snakes with a cockatiel on the guard of Shahzid threshold, its spring, atmosphere, and water reservoir.
Mythical elements
Cow: Cow has been one of the ritual animals in ancient Iran. In the story of Fereydoun and Shahid, the main point is milking a cow, which goes back to the "mother goddess" of cows and raising humans. Since the prince emerges from the crack of the tree, it can be a symbol of the womb that is associated with the tree as the mother goddess. Cow is also closely related to rain and water in mythology. The myth of the god of clouds and rain can be deduced from it according to the myth of Indra and Trita Aptie.
In Dinkard, Fereydoun turns the Mazandaranis into stones. At the command of Ormazd, he firmly binds Zahak like a stone in a cave and achieves happiness and kingship, and the Imamzadeh of Shahzid stones the cattle ranch and cows.
The village of Shahzid is located on the border between the forest and the mountains without trees. In other words, the rainy clouds of the north remain behind the Alborz mountains in this region and collide with each other.
Forest and tree: "In mythology, the forest is a psychological realm having a feminine origin, the place of examination and knowing the unknown dangers and darkness, and the entry to the dark or symbolic haunted area" (Cooper, 2013, p. 110). The relation of forest with fertility, rain, and water could be another confirmation of the main roots of the myths in these two stories.
Snake: "Snakes guard the thresholds and temples, and all the gods depend on them. The two snakes represent the contradictions in the duality that eventually lead to unity" (ibid., p. 349). In the story of Fereydoun, a snake has grown on Zahak and makes him a demonic creature. "According to a version, Fereydoun was a three-headed snake that overcame another three-headed snake, namely Zahak" (Shamisa, 2015, p. 261).
Some scholars consider the word Fereydoun to mean having three spiritual, physical, and medical powers. These three attributes can be found to some extent in Imamzadeh Shahzid: having the spirit of a fighter and purity, being a master and fighting enemies, the symbolic tool of iron with changes in the Galesh's ax, the rosary's medical potentiality and the healing power of the water, and the magical ability in stoning cattle.
The title of Shah, which is used in the Iranian culture for Imams, their sons, and the Sufi followers is remarkable so far as the mythological semiotics is concerned, and it can be analyzed with regards to the story of Fereydoun.
References
Cooper, J. S. (2013). Culture of ritual symbols (translated into Farsi by Roghaye Behzadi). Scientific.
Kazazi, M. J. (2011). Dream, epic, myth (in Farsi). Markaz Publishing.
Shamisa, S. (2015). Expression (in Farsi). Mitra.
Shamisa, S. (2015). Expression (in Farsi). Mitra.
Volume 10, Issue 48 (12-2022)
Abstract
Examining the history of Ashiqs confirms that the peak of the literary creativity of Ashiqs is tied to the period of Safavid rule, and the evolution of Ashiq art took place after that period. One of the famous Ashiqs of Azerbaijan is "AşheqGhorbani". AshiqGhorbani is one of the Ashiqs committed to the court of Shah Ismail Safavi, who was famous and accepted during his lifetime. There is no information about the biography of Ghorbani in the historical sources, but his biography is based on his poems and the story that is narratedin the name of him and his beloved Pari or Parizad, a story that, like other stories of Ashiqlar, is connected with mythology. In addition to Iran, this story is also famous in Azerbaijan and Turkey with differences in epizods. In addition to examining the history of the Ghorbani, this article has compared the storey of "AshiqGhorbani and Pari" in the narratives of Iran and Turkey.Volume 11, Issue 2 (7-2021)
Abstract
Urban historic areas as a living witness of the history of the past and the main factor in collective identity are dealing with dialectic conflict of "development" and "conservation" that leads to different types of conflicts especially secondary ones. Confrontation of conservation and contemporary needs of the residents is one of the challenging issues. So, this paper tries to analyze conflicts toward planning of urban historic in order to define a new conceptual framework for achieving conflict management-driven urban contemporization.
This study has been done based upon qualitative paradigm and the required data have been collected by using snowball sampling, document analysis and in-depth interviews. Analyzing conflict toward planning of urban historic areas has been done based upon grounded theory and bridging conflict management and urban contemporization done based on logical argumentation.
Findings show that the weakness of conservation planning and management system of the historic areas and the inefficiency of planning and management system of development in such areas at decision-making level are the main factors in the confrontation of development and conservation that lead to the emergence of secondary conflicts at operational level. In case of conflict management, it will be possible to combine two concepts of conflict management and urban contemporization.
Managing conflict between development and conservation can be resulted in achieving conservation-led integrative development as a factor of urban contemporization. Therefore, protecting heritage values along with supplying modern needs of residents can be achievable.
Volume 11, Issue 2 (6-2025)
Abstract
The taxonomic status and placement of the Caucasian honey bee (Apis mellifera caucasica Gorbachev, 1916) (Hymenoptera: Apidae) remains puzzling, largely based on outdated investigations. After reviewing available scientific sources, we conclude that initially there was a confusing mismatch between the traditional geographical understanding of the Caucasus and the actual distribution of A. m. caucasica. Insufficient geographic sampling of honeybees across the Caucasus, a statistically inadequate number of studied samples, and incomplete research methodology are major drawbacks of previous studies. Morphometric reference data derived from an extremely limited number of samples still is in use as a standard for the identification of A. m. caucasica. It is highly probable, that this standard does not reflect true morphometric diversity, covering natural geographical variations, which most importantly hinder preservation or breeding efforts. To resolve these deficits, honeybees of the Caucasus and adjacent regions need to be studied in more detail with greater depth of sampling. A thorough study, using modern morphometric approaches and molecular genetic methods, is needed to characterize A. m. caucasica and produce a statistically robust dataset for due reconsideration of its taxonomic status and placement.
Volume 12, Issue 3 (9-2022)
Abstract
Aims: The industrial heritage buildings and sites can be a stage for people to meet, which create memorable experiences. Adaptive reuse of such buildings by applying the experience economy can provide more suggestions so that they can be exploited appropriately by designing different experiences.
Methods: In the present research, related documents and theories are studied by the lense of logical argumentation strategy. "personal context", "social context" and "physical context" based on the theoretical framework of the research have been emphasized.
Finding: The design of experience in Rey Cement factory has been done based on these three components using four realms of Pin and Gilmore. Therefore, proposed uses have been defined according to the principles considered in this research, considering the authenticity of the industrial site and the production of new collective experiences, the result of which is the coexistence of different uses in this site.
Conclusion: The industrial heritage of is the basis for the growth and development. Nowadays, conservation and adaptive reuse of such buildings can be in line with their previous goals in economic development. experience design is one of the newest ways in economics. The results of the research show that experience based design can be a useful tool for heritage conservation. And this research tries to deal with heritage tourism from an experience-based perspective based on the criteria obtained from the conceptual framework of the research. And to better explain the approach, suggestions have been made for the experience-based design of Ray Cement Factory.
Volume 12, Issue 4 (2-2025)
Abstract
The postmodern novels "Divorced Diaries" by Haifa Bitar and "Vanhadeh" by Simon de Beauvoir are the first-person narrators of the daily lives of two divorced women as the protagonists of the mentioned novels. The importance of this research is because the neurotic character of both novels makes it possible to look at the hero of the two novels with a psychotic perspective and to investigate Jeffrey Young's initial inconsistent schemas in their characters with a comparative method. This research is based on descriptive-analytical method. This research aims to have a concrete view of the society of Syria and France and reveal the effective factors in the formation of these schemas in the hero of two novels and scrutinize them with the example of the witness. The research results indicate that the heroines of these two novels are both abandoned by their husbands and suffer from the same primary incompatible schemas. Both protagonists of the novel suffer from various primary maladaptive schemas of dependence/incompetence, defect/shame, and abandonment/instability (abandonment), which, in the order of their origin, depend on/incompetence in them. Relying on the father in doing all the daily tasks, even doing the homework, especially at the teenage age, which is the stage of reaching independence and self-sufficiency. In addition, there is a schema of defect/shame arising from their being rejected by their spouses and their divorce by them, as well as a schema of rejection/instability caused by their shaky relationships.
Volume 13, Issue 3 (6-2013)
Abstract
The main object of current study is investigation of instability threshold of flow in a gradual expansion from symmetric to asymmetric situations. The expansion ratio is 1:3 and expansion angles are 30, 45, 60 and 90 degree. Discretization of governing equations is performed using finite volume method based on PISO algorithm on a staggered mesh. The CFD code is validated based on the results of sudden expansion reported in previous works. Here, the effects of expansion angle and Reynolds number on flow instability in transition from symmetric situation to two and three asymmetric vortices are investigated and the first and second critical Reynolds numbers are obtained. The bifurcation diagrams of vortices and velocity profile in centerline are plotted for each case and the effects of instability on flow field are discussed based on them. Unlike the previous studies which have been focused on the planar flow in sudden expansions, the flow instability in gradual expansions with different expansion angles is investigated which is the main innovation of current study.
Volume 13, Issue 5 (12-2013)
Abstract
Water-storage capacity of reservoir reduces mainly due to sediment laden. Turbidity current has an important role on sediment transfer in reservoir. It is necessary to study sediment interaction and flow in order to predict mechanism of turbidity current. In this paper effects of changes in entrance hydraulic condition of turbidity current on head velocity, layer-average thickness, layer-average velocity, body velocity and turbulent structure have investigated experimentally. The front velocity of the head of turbidity current was determined by video recording and body velocity and turbulence parameters measured by Vecterino. When the initial Froude number decreases the maximum velocity increases in body and head. Positive shear Reynolds stress near bed indicates that major contributor in this region is sweep or ejection while major contributor near interface is inward interaction or outward interaction. Entrainment is dominated at interface. The investigation shows that head velocity depends on inlet Froude number and inlet Reynolds number. Variation of head velocity along channel is exponential. The maximum reduction of head velocity takes place at whereas variation of head velocity at is negligible. Driving forces at are inertial force and gravity force. Driving force decreases after hydraulic jump and only gravity force remains as driving force. Therefore head velocity is constant at . Head velocity increases when inlet Reynolds number increases. Body velocity increases when inlet Froude number decreases, as gravity force increases when inlet Froude number decreases. Effects of inlet Froude as number on body velocity is negligible at the end of channel. Negative value of body velocity at the interface of turbidity current and ambient fluid indicates entrainment phenomenon at this region. When inlet Froude number decreases, vertical component of velocity increases too,then maximum velocity approaches to the bed. Elevation of maximum velocity increases along the channel due to sedimentation of particles and decreases of vertical component of velocity. Body velocity decreases along the channel due to decrease of inertial force. Vertical Reynolds stress decreases when inlet Froude number decreases. Because of increase in particle turbulence dissipates and therefore vertical Reynolds stress decreases. Oscillation of vertical Reynolds stress is due to turbulence at this region. The maximum of vertical Reynolds stress tacks place near bed and interface of turbidity current and ambient fluid and minimum of vertical Reynolds stress tacks place near maximum velocity elevation. Shear Reynolds stress have two maximum values. One is near the bed and the other one is near the interface of turbidity current and ambient fluid. Maximum Reynolds shear stress is positive near bed and negative near interface. Minimum of Reynolds shear stress take place near maximum velocity elevation.
Volume 14, Issue 1 (4-2014)
Abstract
In this research, grey cast iron scraps were recycled into powders and were then used in combination with iron powder for producing iron based powder metallurgy parts. Design of experiments was conducted by response surface method for both the green and sintered parts. For the green properties, the parameters cast iron powder percentage and compaction pressure, and for the sintered parts, the mentioned parameters in addition to sintering temperature and sintering time were selected each in five levels as the input process parameters. Transverse rupture strength and elastic modulus were measured as the responses. Regression analysis and analysis of variance were used to investigate the effect of input parameters, develop the mathematical models and evaluate the validity of the models. Scanning electron microscopy and optical microscopy micrographs were provided to better understanding. The obtained results, in addition to determine the effects of the input parameters, demonstrated the adequate mechanical properties of the produced parts in industrial scales and the validity of the proposed models. Also, the proposed method demonstrated its good capability for estimation of elastic modulus of powder metallurgy parts.
Volume 14, Issue 1 (6-2014)
Abstract
River bank erosion causes damages to agricultural land, adjacent establishments and widening of river dimensions. Mass failure process of bank erosion is a factor to transport bulk of sediments followed by deposition in downstreams of a river system, which could be an important problem in river management. This research is to investigate internal erosion under different bank and floodplain slopes, By this means, a number of experiments were carried out in a model designed to simulate internal river bank erosion in the laboratory. In these experiments, the scour hole length, resulted from internal erosion and seepage discharge were measured under different hydraulic gradients. Results showed that bank slope plays an effective role in scour hole length and calculated Reynolds number in porous medium. As it was observed that the scour hole length and hydraulic gradient decrease with an increase in the bank slope and porous medium Reynolds number decreases with reduction in the hydraulic gradient.
Volume 14, Issue 9 (12-2014)
Abstract
This study focuses on transition of laminar to turbulent flow around a symmetrical airfoil at a low Reynolds number in free flow and flow near the ground at different angles of attack. Finite volume method is adopted to solve the unsteady Reynolds-averaged Navier–Stokes (RANS) equation. Flow around the symmetrical airfoil SD8020 at a low Reynolds number (4000) at 5 and 8 degree angle attack has been simulated in free stream and near the groundnumerically. Current numerical result is compared with other’s experiment and numerical result in free flow at low Reynolds number and flow in ground effect that good agreement has been obtained in aerodynamic coefficient prediction. SIMPLEC method is used for pressure and velocity coupling and flow equations discrete with Quick method. Transition-SST model is used for modeling turbulence of flow. Result shows that the current numerical method can detect adverse pressure gradient, laminar separation bubble and transition of laminar flow to turbulent. According to the result, in ground effect location of laminar separation bubble, length of bubble and location of transition is moved to leading edge and pressure distribution is effected by location of laminar separation bubble.
Volume 14, Issue 11 (2-2015)
Abstract
In this research, the machinability of iron-recycled grey cast iron powder metallurgy parts is investigated. For this purpose, grey cast iron swarfs were transformed to powders by target jet milling method and were then used to prepare powder metallurgy parts in combination with commercial iron powder. Green compacts were prepared with the variables of cast iron powder percentage and compaction pressure. Design of experiments was conducted by response surface method for sintered parts with the variables of cast iron powder percentage, compaction pressure, sintering temperature and sintering time each in five levels. Regression analysis and analysis of variance were used to investigate the effect of input parameters, develop the mathematical models and evaluate the validity of the models. In the green section, machinability was qualitatively investigated in drilling. For sintered parts, machinability was evaluated by measuring the thrust and torque forces and the obtained surface finish in drilling. The obtained results certificated the accuracy of the extracted regression equations for predicting the machining properties of the parts. Also, the results demonstrated that the addition of jet milled grey cast iron improves the machinability of iron-based powder metallurgy parts.
Volume 15, Issue 4 (6-2015)
Abstract
Due to the diversity and width applications of polymeric fluids in various industries the investigation of viscoelastic fluids is noted by many researchers. In this study, non-creep flow of viscoelastic fluid has investigated inside planar channel with gradual expansion for the expansion ratio of 1:3. The laminar and incompressible flow of viscoelastic fluid has been simulated numerically using finite volume method and PISO algorithm. The nonlinear PTT rheological model has been applied to study effect of elasticity property on the length of vortices in polymeric fluid flow. The investigation of symmetric and asymmetric vortices length in a wide range of Reynolds and Weissenberg numbers is the main purpose of present study. The three angles of 30, 45 and 60 degrees have been considered for influence of the expansion angles on the length of vortices. The study of polymeric fluids flow through the planar channel with gradual changes in cross section (with expansion angles less than 90 degrees) is the innovation of this research. Also the critical values of first and second for Reynolds and Weissenberg numbers have been expressed in various expansion angles and furthermore length of second and third vortices has been presented as a function of Reynolds and Weissenberg numbers. The length of symmetric vortices decreases with increment of elastic property at all expansion angles for values of Weissenberg numbers less than one. Whereas the growth of expansion angle leads to increase in the length of symmetric and asymmetric vortices for low Reynolds and Weissenberg numbers.
Volume 15, Issue 4 (10-2024)
Abstract
The purpose of this essay is to review one of Frazad Qaemi’s papers: “Why Does Ferīdōn mean the "Third"? Decoding the Mystery of Ferīdōn’s Name According to Function Analysis of Myth: A Study in Historical Linguistics (Diachronic Etymology)”. The paper shows the writer was not specialist in the subject matter he discussed. Due to his unfamiliarity with the concepts, initial knowledge and the resources of this area, made his analysis and conclusions were flawed. Nevertheless, the way he refers to other works is too unaccustomed, they mostly show that the writer, Qaemi, trying to refer his incorrect thoughts and analysis to reliable sources, and with this technique, he was trying to prove the audience that his incorrect analysis and ideas are correct. Aside from that, Qaemi, used the analysis and accomplishment of other writers, but unfortunately, he did not refer to them in his paper, implying that they were his own, which is clearly plagiarism. The paper contains many errors, making it a good example for methodology courses as it shows students what they should avoid in a journal paper.
1. Introduction
Qaemi’s paper focus on why Fereydun’s epithet is “The Third”. He tried to explore connections between this title with the haoma-preesing rite and the three-brother pattern in Iranian Mythology. Qaemi also examined other subjects and finally considered a three-part Dissociation in Iranian myth.
These are the most important topics of the paper. There are two kind of references for supporting these analysis and ideas, 1: pre- and post-Islamic text. 2- Other scholars’ works.
First, his reasoning and analysis for connecting Fereydun to haoma-pressing function are incorrect because some scholars like Mayrehofer and Boyce point to Vedic texts where Trita appears as the first soma-presser. In Iranian texts, Ābtin (Fereydun’s father) called the second haoma-presser and Freydun’s name is not among haoma-pressing at all. Secondly, the concept of three-brother pattern may be more like a pattern not a function and this idea, like the previous one, does not align with how Fereydun’s myth portrayed in the texts. Therefore, the texts that he used in his paper not only support his analysis and conclusions but also are against them. The texts and resources he mentioned appear irrelevant to the discussions and arguments or sometimes been referred incorrectly. Needless to say conspicuously absent from Qaemi’s analysis is Fereydun’s well established as a dragon slayer. This review tries to show the mistakes occurred by Qaemi in his paper.
2. Method
Firstly, the method of this review is to track Qaemi’s references to verify their accuracy. Secondly, it examines these sources to identify any potential plagiarism or improper citation practices. Besides, this review aims to rectify Qamei’s mistakes (=errors).
3. Results
Through a close analysis of Qaemi’s paper, this review arrives at the following conclusions:
1- The writer had no particular expertise in the topic he chose for his paper. 2- Plagiarism; he used other scholars accomplishment without referring to them. 3- The author used inaccurate references to persuade the audience to agree with his misguided analysis and conclusions. 4- Using Wikipedia in a journal paper. All of this leads the paper to unfavorable scholastic outcomes. It is worth mentioning that this review does not contain every mistakes in Qaemi’s paper just few instances.
Volume 15, Issue 7 (9-2015)
Abstract
This article investigates experimental study of the flow field on a blunt airfoil. For this purpose, PIV technique based on instantaneous flow structures is used in order to view and two dimensional investigation of flow field around unmodified and blunt airfoil and at different times. This study is performed on flows at very low Reynolds number(Reynolds number lower than 4500). This flow regime is very similar to dominant condition on micro air vehicles (MAVs). In order to validate the method used in this study, flow field around cylinder is considered and in continue, instantaneous and mean velocities fields, streamlines and mean vortices field around unmodified and blunt airfoils are obtained. The results show that there are prominent differences on the structure of wake around airfoils and sizes of separation region for blunt and simple airfoils. Meanwhile separation of the flow for both blunt and simple airfoils at this very low Reynolds number, is occurred at angle of attack 5 (at low angle of attack). Also generation of vortex at wake region and their position and circulation at different times, are discussed.
Volume 16, Issue 2 (4-2016)
Abstract
Equal channel angular pressing (ECAP) is one of the most efficient techniques among severe plastic deformation (SPD) methods that enhance the mechanical properties of polycrystalline metals by refining subjected grains. In this article, equal channel multi angular pressing (ECMAP) process as one of the effective ECAP methods on production of ultra-fine grained (UFG) Al5754 strips studied. Route C considered as a multi pressing route and grey relational analysis used as the optimization method. Geometrical parameters were taken as input variables and strain inhomogeneity index, equivalent plastic strain and required process load were taken as the objectives. The suggested tests by full factorial method simulated by FEM. Finite element simulations were done by ABAQUS commercial software and obtained results validated by analytical methods and experimental tests. Then considering all input and output parameters, optimization was done and optimum values of input parameters were elicited. Also, the effectiveness of each parameter on the objective parameters obtained. It is concluded that, among geometrical parameters of route C, die channel angle (ϕ_2) and die corner angle (ψ_1) has the maximum and minimum effectiveness respectively.
Volume 16, Issue 2 (6-2016)
Abstract
Rivers have been always the main source of water for human kind and the basic element of population development. Study of the interaction between flow structure and bedforms is one way to understand the behavior of the rivers. Moreover,vegetation in natural rivers increases roughness of the main channel and flood plains which affects the geometry of channels, flow structure, bed resistance and consequently the pattern of sediment transport. Considering the role of bedforms on sediment transport, turbulence production and flow resistance, investigations on details of flow-bedforms interaction, vegetated banks and flow structure seem to be essential. In this study, the influence of straight crested gravel bedforms and vegetation of the banks of channels on flow turbulent characteristics are investigated based on model experimentation. For this purpose, seven fixed artificial 2-D straight crested bedforms were built inside a rectangular flume of 8 m long, 0.4 m wide and 0.6 m deep. The graded gravel particles used to create the bedforms had an average diameter of d50 = 10 mm. Johnson grasses with a diameter of 2.8 mm were used to simulate vegetation cover on the flume side-walls. Since, the fully developed flow was just observed after the fifth dune, experimental measurements were performed over the fifth and sixth dunes. Overall, three runs were performed over the dunes with a wave length, height, angle of repose and flow depth of 0.96 m, 0.04 m, 28 degrees and 0.28 m, respectively. In the first case 17 velocity profiles and in the second and the third cases 21 velocity profiles were measured. All the tests were performed with a constant discharge of 0.024 m3/s. The instantaneous three-dimensional velocity components were measured using a down-looking Acoustic Doppler Velocimeter ADV. Velocities were recorded for each point with a sampling rate of 200 Hz and the sampling volume of 5 mm. The sampling duration was at least 120 seconds. Overall, about 45400000 velocity data were collected, filtered by WinADV software. Results indicated no negative velocities for both cases of with and without vegetation cover. For no vegetation case, the least value of velocity was zero at a small region on the lee side of the dune. Whereas, for the case of vegetating the side-walls, the zero value of velocity was located at the dune's trough. Negative vertical velocity value in both cases of with and without vegetation along a dune confirmed that separation is not dominant for the case of straight crested dunes compared to the corresponding sharp-crested bedforms. The Reynolds stresses increase for the case of vegetating the side-walls compared to the case of without vegetation cover. This is in part due to the increase of flow resistance, while the side-walls are vegetated. Rivers have been always the main source of water for human kind and the basic element of population development. Study of the interaction between flow structure and bedforms is one way to understand the behavior of the rivers. Moreover,vegetation in natural rivers increases roughness of the main channel and flood plains which affects the geometry of channels, flow structure, bed resistance and consequently the pattern of sediment transport. Considering the role of bedforms on sediment transport, turbulence production and flow resistance, investigations on details of flow-bedforms interaction, vegetated banks and flow structure seem to be essential.