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Wyszukujesz frazę "Akhtar, S." wg kryterium: Autor


Wyświetlanie 1-7 z 7
Tytuł:
Influence of flight control law on spin dynamics of aerodynamically asymmetric aircraft
Autorzy:
Malik, B.
Akhtar, S.
Masood, J.
Powiązania:
https://bibliotekanauki.pl/articles/279175.pdf
Data publikacji:
2017
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
aerodynamic model
steady spin modes
unsteady effects
simulations
Opis:
In this paper, we analyze the spin dynamics of an aerodynamically asymmetric aircraft in open-loop configuration and also evaluate the performance of gain scheduled flight control law in improving dynamic characteristics of aircraft spin. A look-up tables based aerodynamic model is developed from static, coning and oscillatory coning rotary balance wind tunnel test data. As a starting point, all possible steady spin modes are identified by solving the aircraft dynamic model comprising moment equations. The influence of high-alpha yawing moment asymmetry on predicted right and left spin modes is discussed. Six degree of freedom simulations of left and right flat spins are performed in open-loop and closed-loop configurations with the flight control law. Our studies reveal that large amplitude oscillations in the angle of attack and sideslip observed in the open-loop configuration are significantly damped by the control law. The control law reduces the recovery time of the left flat spin. However, the aircraft natural tendency to rotate rightwards due to yawing moment asymmetry at high angles of attack renders flight control law ineffective in aiding the recovery of the right flat spin.
Źródło:
Journal of Theoretical and Applied Mechanics; 2017, 55, 3; 963-975
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comparative analysis of buckling load of circular and corrugated tubes by utilizing key performance indicators
Autorzy:
Rahim, M. R.
Akhtar, S.
Bharti, P. K.
Powiązania:
https://bibliotekanauki.pl/articles/265589.pdf
Data publikacji:
2017
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
buckling load
tubular structures
quasi-static
key performance indicators (KPIs)
circular and corrugated sections
konstrukcje rurowe
pianka aluminiowa
rura cienkościenna
Opis:
The performance of buckling load of tubular structures under quasi-static axial loading is quite appreciable, numerous tubes of various cross-section have been extensively investigated and corrugated sections have been designed to further improve the performance. In this paper, a carefully designed set of key performance indicators (KPIs) is utilized to assess and compare the buckling load of circular and corrugated tubes. A series of diagrams related to KPIs with various parameters of tubes are presented to demonstrate the influence of sectional configuration on the performance of tubes as well as the effect of the material on the potential of the same. The work is inestimable to engineering designs and applications, and further studies on the buckling load of other configurations.
Źródło:
International Journal of Applied Mechanics and Engineering; 2017, 22, 3; 789-797
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Improved cut flower and corm production by exogenous moringa leaf extract application on gladiolus cultivars
Autorzy:
Younis, A.
Akhtar, M.S.
Riaz, A.
Zulfiqar, F.
Qasim, M.
Farooq, A.
Tariq, U.
Ahsan, M.
Bhatti, Z.M.
Powiązania:
https://bibliotekanauki.pl/articles/11855333.pdf
Data publikacji:
2018
Wydawca:
Uniwersytet Przyrodniczy w Lublinie. Wydawnictwo Uniwersytetu Przyrodniczego w Lublinie
Tematy:
Pakistan
Faisalabad city
ornamental plant
Gladiolus
Gladiolus grandiflorus
Rose Supreme cultivar
White Prosperity cultivar
cut flower
corm
corm size
spike length
vase life
growth regulator
Moringa oleifera
leaf extract
climate condition
Opis:
Bio-stimulants are in excessive demand for the sustainable production of floriculture crops. The current investigation was designed to find out the effect of naturally occurring growth stimulant moringa leaf extract (MLE) on the growth, flowering, post-harvest life and corm production of two gladiolus cultivars (cvs.) ‘Rose Supreme’ and ‘White Prosperity’. The research trial was laid out in the factorial arrangement under randomized complete block design. Corms were grown in the open field under local climatic conditions of Faisalabad, Pakistan. Potential of exogenously applied (MLE; 30 times diluted) was evaluated. Treatments including spraying MLE at 3 leaves, 5 leaves, floral bud stage, one combination of these three stages relative to control with no foliar application. Application of natural bio-stimulant produced maximum height in both cvs. against T4. Both cvs. gave maximum stalk length in response to T4. The number of florets spike–1 found the maximum (13) in T1 compared to control T0 which yield (9) florets. Maximum vase life in sucrose solution (13.33 days) was exhibited by T1 for both cvs. while minimum (10 days) in T0. In cultivar comparison earlier spike emergence was observed in ‘White Prosperity’. In ‘Rose Supreme’ maximum corm weight was attained in response to T3 (43.43 g) while minimum (30.33 g) in T0.‘White Prosperity’ produced maximum weight (40.33 g) against T4 whereas minimum by control. The cultivar mean comparison showed the superiority of cormel diameter in ‘Rose Supreme’ (10.93 mm) than ‘White Prosperity’ (9.13 mm). In treatment comparison, T4 produced maximum diameter (12.04 mm) in ‘Rose Supreme’ moreover, T2 induced maximum (9.57 mm) diameter in ‘White Prosperity’.
Źródło:
Acta Scientiarum Polonorum. Hortorum Cultus; 2018, 17, 4; 25-38
1644-0692
Pojawia się w:
Acta Scientiarum Polonorum. Hortorum Cultus
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Noise Monitoring, Mapping, and Modelling Studies – A Review
Autorzy:
Alam, Pervez
Ahmad, Kafeel
Afsar, Shakil S.
Akhtar, Nasim
Powiązania:
https://bibliotekanauki.pl/articles/125244.pdf
Data publikacji:
2020
Wydawca:
Polskie Towarzystwo Inżynierii Ekologicznej
Tematy:
noise mapping
noise monitoring
noise modelling
CoRTN
FHWA
Opis:
This paper reviews the literature on noise monitoring, noise mapping and noise modeling studies carried out in different countries by many researchers. The article reveals the current status of the noise-related studies and noise mapping studies. It was discovered that 90% of the noise monitoring studies were focused on the traffic noise, while the remaining 10% focused on the residential, commercial and industrial areas. Sometimes, there may be a necessity to analyze the sound pressure levels all over the place, or around a particular piece of land and machinery of industry. Researchers have used the noise monitoring data for the development of 2D and 3D noise maps which gives a clear picture of the noise level around the source of noise in X, Y, and Z direction. For taking a decision regarding the noise level for any development project, predicting the noise level is always necessary. The traffic noise models are generally used for the purpose of prediction. Early models are based on constant vehicle speed, later some models predicted the noise level for interrupting the traffic flow. For instance, the Stop and Go model can be used for the prediction of the noise level in an interrupted flow. Four such models were reviewed and compared in this article.
Źródło:
Journal of Ecological Engineering; 2020, 21, 4; 82-93
2299-8993
Pojawia się w:
Journal of Ecological Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Tunnel support design by comparison of empirical and finite element analysis of the Nahakki Tunnel in Mohmand Agency, Pakistan
Autorzy:
Riaz, A.
Jamil, S. M.
Asif, M.
Akhtar, K.
Powiązania:
https://bibliotekanauki.pl/articles/178620.pdf
Data publikacji:
2016
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
rock mass strength parameters
rock mass classification
FEM analysis
Phase2
tunnel support design
Opis:
The paper analyses the geological conditions of study area, rock mass strength parameters with suitable support structure propositions for the under construction Nahakki tunnel in Mohmand Agency. Geology of study area varies from mica schist to graphitic marble/phyllite to schist. The tunnel ground is classified and divided by the empisical classification systems like Rock mass rating (RMR), Q system (Q), and Geological strength index (GSI). Tunnel support measures are selected based on RMR and Q classification systems. Computer based finite element analysis (FEM) has given yet another dimension to design approach. FEM software Phase2 version 7.017 is used to calculate and compare deformations and stress concentrations around the tunnel, analyze interaction of support systems with excavated rock masses and verify and check the validity of empirically determined excavation and support systems.
Źródło:
Studia Geotechnica et Mechanica; 2016, 38, 1; 75-84
0137-6365
2083-831X
Pojawia się w:
Studia Geotechnica et Mechanica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of foliar application of zinc oxide on growth and photosynthetic traits of cherry tomato under calcareous soil conditions
Autorzy:
Sardar, H.
Naz, S.
Ejaz, S.
Farooq, O.
Rehman, A.
Javed, M.S.
Akhtar, G.
Powiązania:
https://bibliotekanauki.pl/articles/13078188.pdf
Data publikacji:
2021
Wydawca:
Uniwersytet Przyrodniczy w Lublinie. Wydawnictwo Uniwersytetu Przyrodniczego w Lublinie
Źródło:
Acta Scientiarum Polonorum. Hortorum Cultus; 2021, 20, 1; 91-99
1644-0692
Pojawia się w:
Acta Scientiarum Polonorum. Hortorum Cultus
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comparison of conventional methods with commercially available topical hemostat surgical snow (oxidized cellulose) for achieving hemostasis in canine model of partial splenectomy
Autorzy:
Zahir, M.
Akbar, H.
Akhtar, R.
Imran, S.
Hussain, N.
Rasheed, H.
Sajjad, T.
Asif, M.
Powiązania:
https://bibliotekanauki.pl/articles/2087172.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
bleeding time
dogs
electrocautery
hematobiochemical parameters
partial splenectomy
Surgicel®
Źródło:
Polish Journal of Veterinary Sciences; 2021, 24, 2; 281-286
1505-1773
Pojawia się w:
Polish Journal of Veterinary Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-7 z 7

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