Aircraft performance mainly relies on the provision of quality air to its engine. An efficient air intake is always designed to grasp air from free stream flow at a specified mass flow rate with minimum pressure loss and least distortion at the required Mach number. In the same context, the behavior of an air intake in response to variations in its local flow field is vital to accommodate aircraft design optimization / future modification requirements. This study is also aimed at evaluating the intake performance of a supersonic aircraft through variations in its local flow field. Reynolds Average Navier-Stokes (RANS) equation-based analysis of the integrated Diverter less Supersonic Inlet (DSI) was carried out earlier using the Spalart Allmaras (SA) turbulence model, which served as the reference for further evaluations in the present work. A pod with known geometry was utilized as a local flow field variation source, which is already under consideration for future integration on the aircraft considered in this study. After creating the required geometric model comprising aircraft, engine, and pod domain, requisite meshing was performed followed by analysis using Computational Fluid Dynamics (CFD). Intake performance was gauged through total pressure recovery at M=0.8 and M=1.5 by varying the pod locations against four angles of attack (-4 degree, 0 degree, 4 degree, 8 degree) at each pod location. Very less variation in total pressure recovery was observed for subsonic flows. For supersonic flows, considerable variation in total pressure recovery was observed for variable pod locations and angles of attack with relatively lower intake performance at pod locations close to the fuselage.
<p>In forensic analysis of any document, Ink mismatch detection provides a very important clue to see whether the document is corrupted or not. In hyperspectral imaging (HSI) ink mismatch detection is used to check whetherthe specific document is written with same pen/ink or different types of pens/inks have been used. In this paper, we show that aHSI of handwritten notes can differentiate between the ink sused to produce the document which are very similar in appearance. The HSI cube we have used for our research has 149 Bands. By using an unsupervised clustering algorithm, we have analyzed the spectral responses of the ink pixels to differentiate between the number of inks used in document. After the successful ink mismatch detection, we have used color labelling to classify the text written with different inks. This technique when applied to a RGB document, is not capable to differentiate between the number of inks used in the document. We hope that our findings and technique will help to examine HSI documents for forensic analysis. </p>
Use of cyclone separator is one of the most effective method to separate dust from the air. It is widely used in industries such as cement manufacturing. In this study, Industrial Standard cyclone separator is computationally analyzed. The main problem encountered in the separator design under this study was its poor yield performance indicated by low separation and collection efficiency. In order to enhance the performance, a parametric study of this cyclone separator flow characteristics has been conducted. A computational model was developed for this industrial scale cyclone separator. Spalart-Allmaras Turbulence model, a 1-equation model, was used for solving the wall-bounded flow as required in this case. The effect of varying inlet pressure and mass flow rate on the performance of the cyclone separator was analyzed. The results indicated that varying inlet pressure increases the velocity range. An increase in separation efficiency was observed by increasing the tangential velocity. The effect of inlet pressure variation on separation efficiency displayed a positive correlation till 150 Pascals (critical pressure) after which, a negative impact was observed. Computational results also exhibited that increasing the mass flow rate abruptly disturbs the flow; the particles start to accumulate at the cone section in the form of layers and hence do not reach the dust outlet. The maximum separation efficiency was indicated at a low mass flow rate of 0.05 kg/s per injection for the current design under study. The results also confirmed that velocity was minimum at the wall due to the no-slip condition. The study hence concluded that to achieve maximum separation and particle collection efficiency for the cyclone separator being used at Industrial Scale, the optimum inlet flow pressure and mass flow rate are 150 Pa and 0.05 Kg/sec per injection respectively.
Low aspect ratio wing-body configurations can achieve higher speeds with interesting aerodynamic characteristics at the stall and post stall. A lot of research is put forth to study the highly turbulent area of a body in this area to understand the complex flow and its effect on the aircraft. One such study is the wing-rock motion of aircraft, which is coupled behavior of aerodynamic and inertial forces. Modern high-speed aircraft designs have been associated with this wing rock and post-stall flight operations. Moreover, this motion also has a great impact during the approach and landing phase, where the angles of attack is very high and the speeds are low. Classical wind tunnel testing provides a great insight into this rocking motion but with the enhanced computing power, a Computational Fluid Dynamic (CFD) approach has become a potent method to study the non-linear coupled aerodynamic characteristics of aircraft geometries. Wing rock is highly dependent on the configuration; various configurations and shapes show a different range of angle of attack, amplitude, and frequency of oscillation of wing rock motion. In this research three cases of different wing- body configurations (A- delta wing, B- delta wing with strakes, and C- double delta wing) were studied at high angles of attacks with 0.11 Mach No. using commercially available CFD tools. The aircraft was subjected to Free-To-Roll motion (FTR), a single degree of freedom rotation motion along the rolling axis using a User Defined Function (UDF). Static CFD analyses were carried out on all three configurations, capturing a wide range of characteristics till 65o angle of attack. Similarly, transient analyses were carried out to capture the vortex flow pattern and wing rock motion of the configurations. During the FTR motion analysis, the rolling motion builds up to the amplitude and frequency of the oscillatory limit cycle. The oscillatory frequency and amplitude motion for, case A (delta wing body configuration) at 40o angle of attack is around 4-degree roll oscillation with a frequency of 0.815 Hz, on rest of the angle of attack the rock motion does not appear to show stable behavior at long range of angles of attack. For case B (delta wing body with strake configuration) the rock motion appears from 40o to 50o with varying amplitude of ±12o. Whereas, for case C (double delta wing body configuration) the behavior of wing rock was not observed. Detailed roll motion is presented along with flow path lines to understand the physics contributing towards the wing rock motion at high angles of attack and its correlation with different configurations. Since the rock motion of the delta wing body with strake configuration shows a relatively better understanding of this motion, therefore analyses of the complete range of envelope are presented. The analyses confirm that a decrease in the rolling moment of inertia (Ixx) increases the frequency of oscillation and vice versa. Similarly, an increase in velocity, while keeping the angle of attack and Ixx constant also increases the frequency of oscillation.
Aerodynamic data primarily pertains to aircraft forces, pressure and moments throughout flight envelope of the aircraft. The current research will generate aerodynamic data set of an Air-Borne Early Warning and Control System (AWACS) based turboprop aircraft under time varying flight conditions using commercially available Ansys Fluent environment. Prior to initiation of unsteady RANS analysis, steady RANS results are investigated for validation, and were found in good agreement against available wind tunnel test results. Unsteady aerodynamic analysis was performed by employing various Wind Turbulence (Gust) models, which included mainly uniform (sharp edge) and discrete (1-cosine, sine) gust models. Gust velocity in pitching direction was introduced by a user defined code in Fluent. A comprehensive study was performed on aerodynamic effects of aircraft by varying gust magnitude, amplitude and gust gradient length. Prediction of critical values for wind disturbance amplitude / magnitude and wavelength was also carried out. Pressure variations on top and lower surfaces of aircraft were studied as gust interacts with aircraft. Changes observed in pressure contours were further elaborated through coefficient of pressure plots. Difference in coefficient of lift, coefficient of moment and coefficient of pressure contour plots for varying gust magnitude, amplitude were also deliberated upon.
Objective: To determine the spectrum of cyanotic congenital heart disease (CCHD) in full term neonates attending paediatric cardiology clinic of a tertiary cardiac care centre. Study Design: Descriptive Cross-sectional study. Setting: Department of Paediatric Cardiology, Faisalabad Institute of Cardiology (FIC), Faisalabad. Period: January 2021 to June 2021. Material & Methods: All full term newborn of any gender with age range from day one to twenty eight days, presenting in emergency or out patient department of the institute and diagnosed as a case of CCHD at Faisalabad Institute of Cardiology on the basis of echocardiography were included in the study.The leading or main anatomical diagnosis of hemodynamically significance was adopted. The spectrum of CCHD was assessed by descriptive analysis. Results: A total of 87 patients were enrolled. Mean age was 15.7±7.98 days. There were 55.2% (n=48) male and 44.8% female (n=39) patients. Majority of patients (62.1%) presented as an emergency. Most CCHDs were of decreased pulmonary blood flow (69%, n=60). Tetralogy of Fallot was the most common CCHD seen in 25.3% neonates (n=22) followed by Transposition of great arteries (23%, n=20) and pulmonary atresia (18.4%, n=16). Ebstein anomaly of tricuspid valve was the least common CCHD (2.3%). Conclusion: Tetralogy of Fallot is the most common cyanotic congenital heart disease followed by TGA while Ebstein anomaly is the least common.
Purpose: To develop a selective, sensitive and accurate simultaneous High Performance Liquid Chromatography (HPLC) method for the analysis of flurbiprofen and famotidine tablet dosage form and excipients.Methods: A simultaneous method for the determination of the two drugs was employed. The assay consisted of isocratic elution of flurbiprofen and famotidine in prepacked Column RT 250-4.6 Purospher® STAR RP-18 end-capped (5 μm), using a mobile phase composed of acetonitrile and phosphate buffer (pH 3.7) in a ratio of 1:1, respectively, as well as an ultraviolet (UV) detector. Flurbiprofen and famotidine were both detected at 265 nm at a flow rate of 1 ml/min following the guidelines of International Conference of Harmonization (ICH).Results: A sensitive and linear range of 10 to 100 ppm with 0.999 coefficient of correlation for famotidine and flurbiprofen were observed. Blank and placebo showed no interference with the peak retention time of flurbiprofen and famotidine. Recovery of 50 mg famotidine was 99.61 % after 12 h and 99.76 % after 7 days and for flurbiprofen 20 mg it were 99.60 % after 24 h and 99.85 % after 7 days.Conclusion: Good precision, recovery and accuracy data indicate the reliability of the proposed method. The method may also be suitable for use in bioequivalence studies.Keywords: Flurbiprofen, Famotidine, Retention time, Limit of detection, Limit of quantification
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