Showing 13 results for gharali
Volume 2, Issue 1 (3-2013)
Abstract
The genus Conophorus Meigen, 1803 (Diptera: Bombyliidae: Conophorini) was studied in the north and northwestern parts of Iran. Three species of the genus Conophorus were identified; two of them are recorded for the first time from Iran, namely: C. pseudaduncus Paramonov, 1929 and C. rjabovi Paramonov, 1929, in addition to C. glaucescens (Loew, 1863), which was previously recorded in Iran. Morphological characters, geographical distributions, and an identification key for the three collected species are provided.
Volume 2, Issue 2 (6-2016)
Abstract
This study was conducted to collect and identify ichneumonid parasitoids of tephritid fruit flies (Diptera: Tephritidae) feeding on the plants of the family Asteraceae in the northwest of Iran during 2013-2015. Five species of ichneumon wasps on five species of fruit flies were reared. They were as follows: Cremastus lineatus on Urophora terebrans; Diadegma maculatum on Hypenidium robrowskii; Scambus brevicornis on Sphenella marginata, Scambus rufator on Terellia gynacochroma and Urophora sp. and Tranosema sp. on Tephritis sp. dioscurea group. Of them, Cremastus lineatus, S. rufator and Tranosema sp. are new records for ichneumonid fauna of Iran. All host-parasitoid-plant associations were newly established to the science. General distribution of these parasitoids and their biological associations were discussed.
Volume 2, Issue 3 (9-2013)
Abstract
One of the most important predator-prey interactions is functional response which its type and parameters are affected by different factors including host plant characteristics. In this research, the influence of leaf surface on functional response and prey consumption rate of third instar larvae of the Episyrphus balteatus (De Geer, 1776) (Diptera: Syrphidae) to third instar nymphs of Aphis gossypii Glover (Hemiptera: Aphididae) were studied on sweet pepper and cucumber leaves. The results demonstrated that leaf surface of host plants; different prey densities and their interaction had significant effects on the numbers of prey killed by a predator. Logistic regression indicated type Ш functional response on both host plant leaves. The values of b constant were 0.00231 and 0.00351h-1 while handling time (Th) estimates were 0.14 h and 0.095 h on cucumber and sweet pepper leaves respectively. Moreover, plant leaves and different prey densities had significant effect on the prey consumption rate and voracity of predator. The maximum voracity values reached were 180.73 ± 7.71 and 282.25 ± 11.71 nymphs on cucumber and sweet pepper leaves respectively. These results emphasize on the importance of physical traits of host plant surface on the performance and searching efficiency of natural enemies that should be considered for optimizing their application in aphid biological control.
Volume 3, Issue 3 (9-2014)
Abstract
The genus Exoprosopa Macqurt, 1840 (Diptera: Bombyliidae: Anthracinae) was studied in the north central Iran. Four species of the genus Exoprosopa were identified of which E. minos (Meigen,1804) and E. grandis (Pallas, 1818) were previously recorded from northern parts of Iran ( or north of Iran ) and two species namely E. efflatounbeyi Paramonov, 1928and E. altaica Paramonov, 1925 are newly recorded from Iran. A key to the species in north central Iran is provided. Morphological diagnostic characters and geographical distribution of the collected species are briefly discussed.
Volume 4, Issue 1 (3-2018)
Abstract
Israelius carthami Richards, 1952 was recorded for the first time from Iran, based on reared specimens from three Asteraceae capitulum: Cirsium congestum Fisch. & C.A.Mey., Carthamus lanatus L. and Xeranthemums quarrosum Boiss. In our rearing, a fruit fly species [Terellia nigripalpis Hendel (Diptera: Tephritidae)] was obtained on C. congestum. All host-plant associations are newly established to the science. General distribution of this parasitoid and their biological associations were discussed.
Volume 4, Issue 2 (6-2015)
Abstract
The fauna of the superfamily Bombylioidea was studied in Alborz province, Iran during 2012. Two families (Bombyliidae and Mythicomyiidae), eight genera and ten species were identified, of which two species, Exoprospora dispar Loew, 1869; Parageron lutescens (Bezzi, 1925), are new records for the Iranian fauna. An identification key for the species of the family Mythicomyiidae known from Iran is given.
Volume 6, Issue 11 (Spring & Summer 2019)
Abstract
The holy Quran is an ocean of meaning, therefore translating it from Arabic language to Persian language and other languages requires the understanding of language delicacies. Today, semantics provide the readers with methods which help them understand the text better and understand its hidden meanings. In words level, the issue of conceptual relationships between the words has been raised in semantics which provide the readers with methods which help them figure out the relationships between the words of a text and detect its implications. One of these relations is semantic opposition between the words. In this article, we have tried to understand the implications of opposite words of Quran in ten last parts of it based on semantic opposition principle using descriptive-analytical method. And we have tried to explain the pathology of these equivalents by critically reviewing Moezzi and Payandeh equivalencies. The significance and importance of this research is that it introduces some of delicacies of literary texts to the translators and shows them some of the probable challenges. Results of this research indicate that ignoring the opposition and emphasizing on basic meaning of words, not paying attention to the multiple implications of opposite words in the context, neglecting morphology of opposite words, not paying attention to the context and collocations of opposite words, and translating the opposite words with incomplete words are the most important pathologies of the two abovementioned translations which have resulted in deficiency in transferring the meaning or in redundancy in these equivalencies in some areas.
Volume 8, Issue 1 (3-2022)
Abstract
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A study was conducted to determine the braconinae (Hym., Braconidae) parasitoid wasps, associated with Asteraceae in the northwest of Iran during 2013-2015. Ten species were reared from flower-heads of Asteraceae:
Bracon bipartitus Wesmael, 1838;
B. leptus Marshall, 1897;
B. luteator Spinola, 1808;
B. mariae Dalla Torre, 1898;
B. pectoralis Wesmael, 1838;
B. subrugosus Szépligeti, 1901;
B. talyshicus Tobias, 1976;
B. trucidator Marshall, 1888;
B. tschitscherini Kokujev, 1904 and
B. urinator (Fabricius, 1798), of which one species (i.e.,
B. talyshicus) is recorded for the first time from Iran. We also reared some non-frugivorous Tephritidae feeding on the collected flower-heads that can be possible host of these braconids. General distribution and biological associations for all species that have been collected in this study are compiled.
Volume 9, Issue 3 (5-2020)
Abstract
The monotypic genus Thaumatorymus Ferrière and Novicky, 1954 (Hymenoptera: Torymidae) is endemic of the West Palaearctic subregion. Thaumatorymus notanisoides, a species rarely sampled, is recorded for the first time from Iran, expanding its known distribution range in the subregion. A brief diagnosis, illustrations and geographical distribution are provided.
Kobra gharali, Eshagh Gharaei, Majid Soltani,
Volume 17, Issue 3 (5-2017)
Abstract
When a Horizontal axis wind turbine works under yaw condition, each blade element can be considered as an oscillating pitch airfoil while the free stream velocity oscillates horizontally. The unsteady free stream velocity, which is usually ignored, oscillates with the same frequency as the airfoil oscillations and has a great impact on the periodic forces produced by the airfoil oscillation. In order to study the effects of unsteady free stream
velocity on the aerodynamic loads, a 2D NACA0012 oscillating airfoil at Reynolds number of 135000 has been simulated. In this simulation, reduced frequency, reduced amplitude and the phase difference between the free stream velocity oscillation and the airfoil angle of attack oscillation are 0.1≤k≤0.25 ، 0.2≤λ≤0.8 و ϕ=0 ,π, respectively. Results show that free stream oscillations affect the aerodynamic loads, vortex strengths
and dynamic stall characteristics. The lift force can be increased by more than 7 times than that of static case and 3 times compared to the load from steady free stream velocity. Depending on 𝜙 value, the dynamic stall angle of attack can be advanced 1 degree or delayed by more than 7 degrees by increase of reduced amplitude. Also, increase of k always causes delay in leading edge vortex formation and consequently delay in dynamic stall occurrence.
Mohammad Reza Ghasemi Bousejin, Ali Jafari, Seyed Saeid Mohtasebi, Kobra gharali,
Volume 17, Issue 9 (11-2017)
Abstract
Research on atmospheric boundary layers in wind farms is an important task. Especially, wind effect on wind turbines installed in mountainous area with complex terrain is complicated. In this research, the wake of a wind turbine and wind flow in complex terrain have studied with computational fluid dynamic (CFD) method in OpenFOAM software. Actuator-disk model with introducing forces, based on Blade Element Momentum Theory, on the disk are used. For simulation of wind turbine in wind farm, Reynolds averaged Navier Stokes equation with k-ɛ turbulence model has been used. Structured mesh was used for simulation domain. Also, main wind direction has been determined from North toward south considering wind rose of area. One of wind turbines is studied by detail. The numerical results show an extended wake effect around 5d (five times the rotor diameter). Wind speed deficit is 26% at this distance. Captured wind power from the simulation is close to real data. Also, wind regime has been studied and analyzed for different seasons. For November, December and January, the time period that wind blows in effective speed, is decreased less than %50 which is important in wind farm design and operation.
Ehsan Bakhtiari, Kobra gharali, Seyed Farshid Chini,
Volume 18, Issue 8 (12-2018)
Abstract
Dynamic motion of a 2D SD7037 airfoil is investigated numerically in presence of a slip boundary condition. The dynamic motion of the airfoil is a harmonic oscillation, where the frequency and the amplitude of oscillations were adequate to airfoil to undergoing dynamic stall phenomenon. Dynamic stall occurred when the dynamic motion of the airfoil causes dynamic stall vortices, resulting in leading edge and trailing edge vortices which lead to rising the aerodynamic loads significantly. Analyzing the phenomena is challenging especially when a slip boundary condition exists near the airfoil wall. This particular condition is the general property of super-hydrophobic surfaces. These surfaces could potentially prevent the blade from icing. The main characteristic of these coatings is the appearance of a slip velocity on the wall. The slip velocity can affect the airfoil aerodynamics which is the main purpose of this paper. In this regard, a 2D airfoil with the Reynolds number of Re≈4×〖10〗^4 is analyzed using computational fluids dynamics (CFD). The Transition-SST model is applied. The results showed that not only the slip condition affects the aerodynamic loadings, but also the dynamic stall regimes changed considerably. So that for slip lengths higher than 100 micrometers, the maximum magnitude of the lift coefficient damped by 16%.
M. Sangbori, A. Nejat, K. gharali,
Volume 20, Issue 3 (March 2020)
Abstract
In this article, noise generation mechanisms are studied at different Reynolds numbers and angles of attack. Tonal noise is the major part of airfoil noise at low Reynolds numbers. Studying the tonal noise and the effects of Reynolds number and angle of attack is challenging in aeroacoustics. 3D numerical simulation is conducted using the large eddy simulation method on SD7037 airfoil. Sound propagation is computed using the Ffowcs Williams-Hawkings (FW-H) analogy. The numerical results are validated using available experimental results. Some discrete peaks and a dominant peak exist in frequency spectra at low angles of attack. Increase of Reynolds number and the angle of attack decreases the number of discrete peaks and at high angles of attack and the dominant peak is diminished too. Studying the flow features shows that when a laminar boundary layer covers a vast area of the suction side, it can amplify acoustic waves that are generated in wake of the airfoil and this mechanism causes a dominant peak in the acoustic spectrum. Amplifying Tollmien-Schlichting waves by shear layer in laminar separation at suction side cause the discrete peaks and when a transition occurs in the airfoil suction side, discrete peaks are diminished. In the original semi-empirical Brooks, Pope and Marcolini (BPM) formulation, the boundary layer thickness of the pressure side is usually used as the length scale and it is replaced by the suction side boundary layer thickness. The results predict the frequency and amplitude of tonal noise successfully.
