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Showing 3 results for Khalghani


Volume 1, Issue 1 (3-2012)
Abstract

This study was conducted to evaluate the age-specific functional response of Psyllaephagus zdeneki Noyes & Fallahzadeh (Hymenoptera: Encyrtidae) at different nymph densities of olive psyllid, Euphyllura pakistanica Loginova (Hemiptera: Psyllidae). Due to parasitoid behaviour of feeding and parasitizing the host, both traits were separately explored on a daily functional response. Results of logistic regression revealed a type II functional response of the wasp independent of their ages. The handling time (Th) and searching efficiency (a) were estimated using the Rogers equation. The highest searching efficiency for both parasitism and feeding was observed in the first five days of the adult age. The handling time for parasitism and host feeding increased with the age of female wasp. The highest searching efficiency and shortest handling time for host attacked (Parasitism and feeding) were gained in day 5 and day 2 and maximum parasitism and host feeding in days 2 and 3 of adult female age, respectively. We conclude that P. zdeneki demonstrated a reasonable performance as a potential biocontrol agent by feeding and parasitism of E. pakistanica which gained its maximum efficiency within 2 to 5 days of its life.

 


Abbas Khalghani, Mohammad Hassan Javareshkian, Mahmoud Pasndideh Fard,
Volume 15, Issue 10 (1-2016)
Abstract

The aerodynamic characteristics of nine configurations of supersonic continuous deflectable nose guided missiles have been investigated. Then the optimized geometry is achieved based on the maneuverability from aerodynamic and flight dynamic point of view. The studied configurations consists of a spherical nose tip, a tangent ogive, one set of stabilizing tail fins and a cylindrical body that its mid-section is flexible to form an arc of a circle. So the cylindrical body consists of a fix part in vicinity of nose, middle flexible part and main body with stabilizers. The effects of fix length and flexible length parameters on the aerodynamic and flight dynamics of guided missile have been studied. A code has been developed to solve full Navier-Stokes equations using finite volume and modified Baldwin-Lomax turbulence model. Multi-block technique is also used to solve main body and fin parts flow field. Further, a 3 degree of freedom code has been developed to compare planar flight dynamic of missiles. It is found that missiles with bigger lengths for fix and flexible parts show more aerodynamic maneuverability, but drag force grows concurrently. Flight dynamic analysis shows that drag effect is negligible and aerodynamic maneuverability analysis is compatible with flight maneuverability.
Abbas Khalghani, Mohammad Hassan Javareshkian, Mahmoud Pasandideh Fard,
Volume 16, Issue 1 (3-2016)
Abstract

The flight dynamics of nine configurations of supersonic continuous deflectable nose guided missiles have been investigated. The studied configurations consist of a spherical nose tip, a tangent ogive, a set of stabilizing tail fins and a cylindrical body that its mid-section is flexible to form an arc of a circle. So the cylindrical body consists of a fix part in vicinity of nose, middle flexible part and main body with stabilizers. The effects of fix length and flexible length parameters on the flight dynamics of surface to surface, antiaircraft and antimissile missiles have been studied. A code has been developed to solve full Navier-Stokes equations using finite volume and modified Baldwin-Lomax turbulence model. Further, a 3 degree of freedom code has been developed to compare planar flight dynamics of missiles. This code consists of a guidance subroutine based on pure persuit law. The results show that even increase of fixed and flexible lengths enhance the maneuverability of the missile, but in some scenarios this can lead to increased flight time and more errors in the target engagement. Deflected nose relocates mass center away from the axis and a thrust vector torque is created. Study of surface to surface scenario shows that this torque improves accuracy of targeting and the ability of target dislocation. In air defense missiles, increase of Fix and Flex variables, will extend the limits of allowable firing angle. However, a heavy nose increases the role of thrust torque and subsequently decreases the role of nose geometry.

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