Reconstruction of aerodynamic angles from flight data for "slybird" Unmanned Aerial Vehicle (UAV)

The angle of attack and the sideslip angle are significant parameters describing the aerodynamics of the aircraft. Specifically, these angles are required for identification of the system parameters such as aerodynamic forces and moment derivatives. For exact measurements, it is necessary to install appropriate air data sensors on board. However, it is sometime difficult to install such apparatus on small UAVs. Inertial sensor measurements, aerodynamic derivatives and equations of motions are used to determine the aerodynamic angles. In this paper, three approaches are followed to estimate airflow angles. The first concept uses navigational equations for the estimation. In the second approach, inertial sensor data has been used. Third concept uses aerodynamic derivative obtained from wind tunnel testing. Estimated angles from all three approaches are shown for simulated and flight data. Complementary filter has been used for combining estimated angles obtained using inertial measurements and aerodynamic derivative based approaches. Improved filtered angles are compared with simulated airflow angles for the same flight condition

Multiplicative Error State Kalman Filter vs Nonlinear Complimentary Filter for a High Performance Aircraft Attitude Estimation

Modern control law designs increasingly use aircraft attitude information to improve aircraft manoeuverability. Attitude information allows for gravity term compensations in the longitudinal as well as lateral directional control laws of a typical fighter aircraft. Methodologies and comparisons of multiplicative error state Kalman filter (MEKF) and nonlinear complimentary filter for estimation of attitudes of a high performance aircraft using its onboard autonomous sensors is presented. Shows a problem in pitch angle estimation beyond ± 80 deg in the MEKF and a solution is proposed for the same for the first time. Also presents novel aiding sensor modelling for the implementation of attitude heading reference system for this class of aircraft for the first time. The filter formulations are evaluated using full range manuoevering real flight test data

Evaluation of novel attitude estimation algorithm for high performance fighter aircraft

This paper discusses the evaluation of a novel attitude estimation algorithm (Kamali et al.(2013)) for a high performance fighter aircraft. This algorithm employs a new modelling approach in the Extended Kalman Filtering (EKF) framework to estimate aircraft attitude information without using forward acceleration sensor, Global Positioning System (GPS) sensors or magnetometer. Evaluation of the algorithm is conducted using flight data from a high performance fighter aircraft and using flight simulation data. Estimation results during various manoeuvres such as full rolls, inverted loops, split-S manoeuvres, steep climbs, and dives, are studied. Effect of different wind perturbations (gust, shear,turbulence, etc.), on estimation results, is also studied. Results using flight data are compared with those obtained from a GPS-assisted Inertial Navigation System (INS), whereas for results using simulation data, the simulation itself provides true values. Conclusions are drawn for the performance of the algorithm based on simulation and flight data

Real-time Desktop Flying Qualities Evaluation Simulator

This paper presents the application of model based design for the development of a real-time flying quality evaluation simulator named NALSim, built around Windows platform. NALSim is a novel rapid prototyping system based on MatlabR, SimulinkR and the Real-Time-Windows TargetR, applicable for fighter, transport and unmanned air vehicles/micro air vehicles simulations. The simulator uses state of the art modeling and simulation technologies to validate various design and flying quality concepts. NALSim is developed such that it is scalable and low cost. The paper presents the simulator architecture and its application for flying qualities. A novel non linear Least Squares optimization based methodology is proposed for efficient handling quality studies.Defence Science Journal, Vol. 64, No. 1, January 2014, DOI:10.14429/dsj.64.496

Calibration and accuracy determination of airdata system for a modern fighter

An Air data system (ADS) is an essential avionics module found in modern fighter aircraft cockpits. It provides critical information about the aircraft to the pilot throughout the flight regime. Airdata system comprises of air data computer and their associated sensors. Sensors instrumented on aircraft normally measure pressures and flow angles in the local flow field using vanes and probes. However, aircraft requires the free stream parameters for flying. Therefore, forward lookup tables in Air Data Computer (ADC) are used to covert local parameters measured using airdata sensor to free stream parameters. In order to design flight controls, improved system performance, ADS should deliver accurate output. Accuracy of free stream parameters depends upon the accuracy of these tables in Air data computer. In this paper, the airdata system of a modern fighter aircraft is considered. This system carries airdata tables which are calibrated/updated using Maximum Likelihood Estimation (MLE) method. The accuracy of it needs to be determined by another independent technique. Hence an Extended Kalman Filter (EKF) is proposed to calibrate and describe the accuracy limits of airdata system. The technique is tested with flight data and the results demonstrate the strength of the technique for airdata calibration and accuracy determination

Development of polymorphic microsatellite loci for Iranian river buffalo (Bubalus bubalis)

Microsatellite loci were developed using PCR-based isolation of microsatellite arrays (PIMA) for Iranian river buffalo. Blood samples of eighty unrelated individuals from four buffalo populations (Khuzestan,Mazandaran, Guilan and Azarbayejan) were taken and following DNA extraction, isolation of microsatellite loci initiated using enrichment with random amplified polymorphic DNA (RAPD) primers. RAPD-PCR fragments were ligated into PTZ57R TA cloning vector and transformed into DH5competent cells. Obtained colonies were screened for presence of repetitive elements by repeatspecific and M13 forward and reverse primers. After designing primer pairs for repeat containing fragments, they were tested in all buffalo populations. Two microsatellite loci (RBBSI and RBBSII) were informative and polymorphic. Number of alleles for RBBSI and RBBSII in 80 individuals was 5 and 6, respectively. Expected heterozygosity ranged from 0.65 to 0.81. Significant deviation from Hardy-Weinberg equilibrium expectation occurred for both loci in all populations, but 37.5% of locus/population combination showed the deviation. We postulate that the two newly isolated microsatellite loci during this study could be useful for population genetic studies in Bubalus bubalis

Radio continuum of galaxies with H2_{2}O megamaser disks: 33 GHz VLA data

We investigate the nuclear environment of galaxies with observed 22 GHz water megamaser in their subparsec edge-on accretion disks, using 33 GHz (9mm) radio continuum data from VLA, with a resolution of ~ 0.2-0.5 arcsecs, and relate the maser and host galaxy properties to those of its radio continuum emission. Eighty-seven percent (21 out of 24) galaxies in our sample show 33 GHz radio continuum emission at levels of 4.5-240 $\sigma$. Five sources show extended emission, including one source with two main components and one with three main components. The remaining detected 16 sources exhibit compact cores within the sensitivity limits. Little evidence is found for extended jets (>300 pc) in most sources. Either they do not exist, or our chosen frequency of 33 GHz is too high for a detection of these supposedly steep spectrum features. In only one source among those with known maser disk orientation, NGC4388, we found an extended jet-like feature that appears to be oriented perpendicular to the water megamaser disk. Smaller 100-300 pc sized jets might also be present, as is suggested by the beam-deconvolved morphology of our sources. Whenever possible, central positions with accuracies of 20-280 mas are provided. A correlation analysis shows that the 33 GHz luminosity weakly correlates with the infrared luminosity. The 33 GHz luminosity is anticorrelated with the circular velocity of the galaxy. The black hole masses show stronger correlations with water maser luminosity than with 1.4 GHz, 33 GHz, or hard X-ray luminosities. Furthermore, the inner radii of the disks show stronger correlations with 1.4 GHz, 33 GHz, and hard X-ray luminosities than their outer radii, suggesting that the outer radii may be affected by disk warping, star formation, or peculiar density distributions.Comment: 18 pages, 10 figures, Accepted for publication in A&

Reverse osmosis reject water management by immobilization into alkali-activated materials

Water-intensive industries face challenges due to water scarcity and pollution. In the management of these challenges, membrane processes play an important role. However, they produce significant amounts of reject waters, in which the separated salts and pollutants are concentrated. This study aims to develop a novel management concept for reject waters using alkali activation to immobilize salts in a solid phase using metakaolin, blast furnace slag (BFS), or their mixture as precursors and to create alkali-activated materials with sufficient properties to be potentially used in construction applications. Seven different waters were used to prepare the NaOH-based alkali activator solution: deionized water, three simulated seawaters with increasing salinity, and three reverse osmosis (RO) reject waters from mining or pulp and paper industries. Overall, BFS-based samples had the highest immobilization efficiency, likely due to the formation of layered double hydroxide phases (hydrotalcite, with anion exchange capacity) and hydrocalumite (chloride-containing mineral). Moreover, high-salinity water enhanced the dissolution of precursors, prolonged the setting time, and increased the compressive strength compared with nonsaline water. Thus, the obtained materials could be used in construction applications, such as backfilling material at mines where RO concentrates are commonly produced

Demonstration of Calreticulin Expression in Hamster Pancreatic Adenocarcinoma with the Use of Fluorescent Gold Quantum Dots

BACKGROUND: There is dire need for discovery of novel pancreatic cancer biomarkers and of agents with the potential for simultaneous diagnostic and therapeutic capacity. This study demonstrates calreticulin expression on hamster pancreatic adenocarcinoma via bio-conjugated gold quantum dots (AuQDs). MATERIALS AND METHODS: Hamster pancreatic adenocarcinoma cells were cultured, fixed and incubated with fluorescent AuQDs, bio-conjugated to anti-calreticulin antibodies. Anti-calreticulin and AuQDs were produced in-house. AuQDs were manufactured to emit in the near-infrared. Cells were further characterized under confocal fluorescence. RESULTS: AuQDs were confirmed to emit in the near-infrared. AuQD bio-conjugation to calreticulin was confirmed via dot-blotting. Upon laser excitation and post-incubation with bio-conjugated AuQDs, pancreatic cancer cell lines emitted fluorescence in near-infrared. CONCLUSION: Hamster pancreatic cancer cells express calreticulin, which may be labelled with AuQDs. This study demonstrates the application of nanoparticle-based theranostics in pancreatic cancer. Such biomarker-targeting nanosystems are anticipated to play a significant role in the management of pancreatic cancer