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The flight dynamics of small Unmanned Aerial Vehicles (UAVs) exhibits substantial nonlinear features which should not be ignored in simulation or analysis. In this work, a complete six degrees of freedom (6DOF) and high-fidelity simulation model of a case study of a small fixed-wing UAV is developed. To accurately estimate the nonlinear UAV’s mathematical model, the mass-inertia properties are investigated through experiments. Moreover, the aerodynamic model characteristics are estimated using a semi-empirical technique to estimate the aerodynamic coefficients and derivatives. The propulsion system’s physical characteristics are estimated and analyzed through experimental measurements. The International Standard Atmosphere (ISA) tables are used to develop the atmospheric model. Furthermore, the actuation model is estimated and validated experimentally through system identification techniques. These estimated sub-model data are integrated to complete the nonlinear flight dynamics model in MATLAB® (Simulink). The UAV trim calculations are graphically derived and then the developed model is tested and verified. The open loop simulation results have proved the superiority of the utilized model techniques to describe the UAV motion. Moreover, it gives very optimistic results to test the flight dynamics of the UAV and design a consistent flight control and guidance system.

Modern turbojet engines are controlled using digital controllers. First of all, the micro turbojet engine discrete model is identified. System identification technique utilized real data obtained from jet cat P200sx engine running experiments. Digital PID controllers are mostly used for controlling these engines. The tuning techniques for digital PID controller parameters are of a great interest. Two tuning techniques are used in this paper to tune the PID controller parameters for the discrete model obtained. In the first, model based local optimal control technique is used to tune the PID controller parameters around certain operating points along the whole range. This technique is used for the first time with the concerned engine. The gain scheduling is used to manage the controller parameters around these operating points. In the second technique, genetic algorithms are used at different operating points along the whole range of operation. Also, the gain scheduling is used to manage the controller parameters around these operating points. The two tuning techniques are compared in Matlab simulation environment. The comparison is based on each controller robustness against noise effect and disturbance rejection. The simulated results are discussed and show better behavior for the digital PID controller tuned using model based local optimal control.

In this paper, the performance of a small centrifugal compressor of an UAV at design and off-design operational conditions is estimated by way of advanced commercial CFD code, ANSYS-CFX-16. Then, the gained performance is compared with published predicted performance using approximate method[1, 2]. The engine used is JetCat P200-sx, which is a single spool turbojet. Considered off-design regimes include centrifugal compressor operations at 73%, 80%, 85%, 90%, 100% and 103% of the design point rotational speed. Commercial CFD code CFX-16, is used for compressor performance prediction at design and off- design operating conditions. The computational grid is created using Turbo-Grid for compressor parts impeller and vanned diffuser. While for both intake device and vaneless diffuser an unstructured tetrahedral mesh with prism layers along the wall surfaces using ANSYS-ICEM CFD mesh is used to resolve the near-wall boundary layer. To gain a reduction in the computational analysis cost, only one passage is considered as a portion of the computational domain and the model is simulated as a steady state problem. Finally, to detect the surge point at each rotational speed the unsteady simulation on performance predictions of centrifugal compressor is investigated. It is a common practice to use compressor characteristics available in graphical form. These plots can be transformed into empirical equations that can be used in automatic calculation. Such approach was done to predict the same compressor performance[13]. The CFD detailed compressor performance is compared with the mentioned published one. The numerical CFD results illustrate good agreement with the analytical model.

This study represents a measurement uncertainty model for rotor vibration amplitudemeasuring system. The measuring system is established to provide a simple way forrotor vibration measurement and consists of a combination of different sensors. Asimple data acquisition software is resolved using LabVIEW. This program enablesdisplaying and recording the directly measured data. Type-A and type-B uncertaintiesare estimated in detail for measuring results. The two different types are combined toevaluate the deviation of readings resulted from several sources. The overall systemaccuracy for rotor vibration amplitude is derived from combining uncertainties of thetwo measured perpendicular vibration displacements. An error bar is provided foreach reading to indicate the possible deviation with 95 % level of confidence.Uncertainty detailed calculation for rotor vibration amplitude measuring system iscomputed as a function of the directly measured values.

Digital controllers are utilized for controlling modern gas turbine engines. Firstly, an identified discrete model is built for a micro turbojet engine (MTE) jet cat P200sx. Two controllers are designed, gain scheduling PID and adaptive fuzzy tuned PID controllers are presented in this paper. Analysis of traditional PID and Adaptive fuzzy tuned PID controller applied for micro turbojet engine is presented. According to the fuzzy rules, a fuzzy logic controller (FLC) is developed to modify the gains of the PID controller automatically. MATLAB/Simulink is utilized to simulate the complete device consisting of an adaptive fuzzy PID controller, and the micro turbojet engine model. The two controllers’ responses are compared. A comparison of the robustness of each controller against the effect of noise and rejection of disturbance is illustrated. The results showed that, through small rise time, small set time, minimal overshoot, and minimal SteadyState speed error, the PID controller adaptive fuzzy tuned provides better dynamic MTE action and thus superior performance.

This paper describes the automation of 3D design and aerothermodynamic analysis of a high pressure, single-stage axial flow turbine driving the compressor of the small gas turbine engine Jet Cat p200 using an analytical method. The specifications of design are based on the reverse engineering of the small gas turbine. Baseline design parameters such as flow coefficient, stage loading coefficient are close to 0.5 and 1.16 respectively with maximum flow expansion in the NGV rows. In the thermal cycle and 1D analysis calculations, the total conditions of all engine stations and all design controlling parameters are determined. In 2D design analysis, the mean line approach is used to generate the turbine flow path and 2D airfoil design, and by using the free vortex law of blading, five blade sections are generated. These sections are at hub, mean and tip and two intermediate sections between hub-mean and mean-tip using an approximate method to the Ainley, Mathieson, Dunham and Came loss model to meet the design constraints. An average exit swirl angle of less than 5 degrees is achieved leading to minimum losses in the stage. Also, NGV and rotor blade numbers are chosen based on the original turbine object. Blade profile is redesigned using the results from blade-to-blade analysis and through-flow analysis using special analytical method, [1]. Aerothermodynamic parameters like pressure ratios, aerothermodynamic power, and efficiencies are computed analytically. The results are compared with the published data in the engine manual.

Rotor vibration due to unbalance causes a lot of problems during operation. One of the simplest ways to reduce rotor vibration is the passive balancing. Unbalanced vertical rotor is modeled by a two degrees of freedom system considering Jeffcott model assumption. A (2+n) degrees of freedom mathematical model is derived with respect to a Cartesian co-ordinate system for the unbalanced rotor with the automatic ball balancer. The model equations are expressed as state equations then solved numerically to calculate vibration amplitudes and angular positions of balancing balls. Model validation is achieved by comparing these results with a three-dimensional model. The effect of the automatic ball balancer on vibration amplitudes is explained at different speed ranges. A parametric study is done to explain the effect of the system damping coefficient on the ball balancer behaviors.

In recent years, mono-propellant propulsion has attracted widespread attention in space due to excessive benefits of safety, low cost, simplicity, clean exhaust and high reliability. A 5N monopropellant Hydrogen Peroxide (H2O2) thruster is selected to be utilized with remote sensing (RS) satellites for attitude control and orbit correction. In the present paper, comprehensive theoretical analysis and design parameters are investigated. The effects of change in various design parameters are studied, such as operating pressures (7-16 bar), H2O2 concentration (70-95%) and initial temperature (25-70℃). The crucial design performance of thruster has been carried out by using thermo-chemical software package. A conceptual design was conducted to determine the dimensions of the thruster prototype including the injector plate, catalytic bed, retainer and nozzle part. 70℃ H2O2 preheating temperature might be needed for catalytic bed fast response. The results are described in the form of graphs and tables for the quick and easy analysis.

Rotor vibration due to unbalance causes a lot of problems during operation. Passive balancing devices represent one of the simplest ways to reduce rotor vibration. A (2 + n) degrees of freedom mathematical model is derived with respect to a Cartesian co-ordinate system for the unbalanced rotor with the automatic ball balancer. The model equations are expressed as state equations then solved numerically. Experimental rig is developed with a data acquisition system to enable measuring the rotor vibration amplitudes. A four balls automatic ball balancer (ABB) is designed, manufactured, and attached to the rotor. The numerical solutions of rotor vibration with and without the balancer are obtained and compared to the measured data to validate the mathematical model. The applied effect of the automatic ball balancer on vibration amplitudes is presented at different speed ranges.

For many reasons, electrical propulsion systems are the most expected in space; they are suitable for researchers because they are effective, easy to design and applicable in space. One of the most important parameters that could assess the performance of the propulsion system is the problem of measuring the very low thrust of pulsed plasma thrusters (PPTs). Various test beds, including indirect designs of measuring systems such as pendulums and optical measuring systems, can measure the thrust with very high precision, but it is very complicated. This paper presents the firing test of a new designed coaxial pulsed plasma thruster for proofing the concept and then the thrust is measured by a new simple test bed using a rod in accordance with a loading cell (0-100 gf.) which can measure thrust accurately after good calibration up to μgf. In a medium-sized vacuum chamber (VC) (10−5 bar, D= 1 m and L= 1.4 m), a coaxial PPT is designed and tested under environmental conditions in space. Four proofs of concept took place until the experiment was adjusted and six experiments were carried out to measure the thrust using the new test bed under various operating conditions. Evaluation of the system is presented too and the maximum thrust obtained is 0.68mN at the discharge voltage equals 7kV and the 12kV voltage of the spark plug initiator and the efficiency equals 10%. The steps of fabrication of the coaxial PPT and steps of measuring the thrust is presented in the paper beside the result charts of the thrust under different operating conditions.

The heat pipe is a thermal device which allows an efficient transport of thermal energy. In this paper parametric study has been achieved to investigate the importance of using heat pipes about the uniformity of the temperature distribution over the equipment panel of the spacecraft (SC), which is a part of a real thermal control subsystem. Heat pipe analytical solution is used as a guide for design and geometrical parameters selection. The design of SC equipment panel radiator and a parametric study of the heat pipe are obtained numerically using Thermal desk top program (TDT). The space environment and the spacecraft operational conditions have been simulated by TDT program. Heat pipe prevents the hot spots which can be occurred due to the different equipment heat dissipation. The selected heat pipe design approach incorporates a conservative reliability philosophy and provides maximum operational flexibility.

There is a great interest on the strategical plan in Egypt for the cultivation of a new crop used as source of natural sweeteners Stevia rebaudiana (Spanti) and (China-1) var. Stem nodal segments containing axillary buds were used as an explant and inoculated on Murashige and Skoog’s (MS) medium containing 3% (w/v) sucrose, 0.8% (w/v) agar supplemented with various concentrations of flurprimidol (flur.), paclobutrazol (PBZ) and thidiazuron (TDZ). In Spanti var. maximum number of branches (6.52) and (6.4) were obtained in MS medium supplemented with 0.12 mg/l flur. and 0.2 mg/l TDZ, respectively with an average of 56.4 and 36.67 leaves per plantlet, having an average shoot length of 6.40 and 6.52 cm, respectively. The best in vitro root induction (100%) was achieved on MS medium with 0.16 mg/l flur. with an average of 10.00 roots per plantlet and root length of 4.82 cm (Spanti var.). Furthermore, in China-1 var. (MS) medium supplemented with 0.16mg/l flur. induced the best morphological characteristics. The rooted plantlets from explant planted on (MS) medium supplemented with 0.16 mg/l flur. were successfully established in soil and grown to maturity at the survival rate of 100% in the greenhouse in (Spanti) and (China-1) var. As a result of anatomy, all studied growth regulators significantly enhanced the anatomical characters of stevia varieties leaf and stem.flur.at 0.16 mg\l surpassed, for instance, midvein and lamina thickness, length and width of leaf vascular bundle as well as stem diameter, xylem and phloem thickness. Our data revealed that the numbers of protein bands in most of treatments are bigger than which in the control.

NASA rotor 37 is among the most popular rotors that have been manufactured to date. It was designed and tested in early 1980’s by Reid and Moore at NASA Glenn Research Center. It consists of 36 blades with multiple arc profiles, and was designed for compressors with compression ratio of 2.05 at mass flow rate of 20.19 kg/s. Also, it was tested in isolation with circumferentially uniform inlet flow so that the flow through it should be steady apart from any effects of passage to passage geometry variation, and mechanical vibration. As such it represents the simplest possible type of test for a real challenge to 3D viscous flow solvers because chock wave-boundary layer interaction is strong and the effects of viscosity are dominate in determining flow deviation and hence pressure ratio. Computational fluid dynamics (CFD) predictions were obtained by ANSYS-CFX 11.0 with k- turbulence model, and were compared with experimental data which has been taken by NASA. The code predictions (with a uniform and spanwise varying outlet static pressure) show good agreement with respect to measured overall performance characteristic, averaged pitchwise distributions, and averaged spanwise distributions. So, the code now is verified to use with the turbulence model, for farther calculation of turbomachinery. Specially, compressors, compressors blades, and compressors cascade.

To draw a profile, and study the media habits for cigarette smokers in Saudi Arabia using the Target Group Index survey (TGI).A household survey using the TGI sample was conducted in March 2008 in 21 cities in Saudi Arabia. A sample of 7003 individuals aged 15 years or more, male and females, living in town and cities, were randomly selected using the multistage sampling technique. One individual per household was interviewed using a structured questionnaire covering socio-economic profile, media exposure, and cigarette consumer information. The study was conducted in Arabian Center for Tobacco Control, Riyadh, Kingdom of Saudi Arabia.Cigarette smoking was 35.9% in males, and 2.3% in females. This was significantly higher in the age group 30-49 years compared with younger ages (p=0.001). Among smokers, 22.3% were heavy smokers, 69.3% were using regular flavor cigarettes, and 22.4% tried to quit smoking but failed. The most common methods of quitting smoking were; nicotine gum (18.5%), hypnosis (14%), nicotine patch (8%), and acupuncture (3%). Ninety-eight percent of the smokers watched TV daily, noticed mainly big outdoor ads, and 46% used the Internet daily. Favorite TV and radio channels, newspaper, magazine, and interesting topics for the smokers were recorded, and the main smoker profile was drawn.The TGI can be used to draw a smoker profile and identify different segments with the greatest opportunities to send anti-smoking messages.

To evaluate the sero-response to measles component of the first measles, mumps and rubella MMR dose given at 12 months by measuring measles antibody before and one month after the vaccination.A follow-up study where, 57 children at the age of 12 months were recruited randomly from the Primary Health Care Centers in Qassim, Saudi Arabia using a multistage sampling techniques. Fieldwork was conducted from October until December 2006. Blood samples were collected to measure measles IgG antibody before, and one month after giving MMR using enzyme linked immunosorbent assay. Data were compared before and after vaccination using geometric mean titer GMT and seroconversion.In the 57 infants, positivity rate increased significantly from 3.5% (2/57) pre-vaccination to 100% one month after p=0.0001, and with a sero-conversion of 96.5% (55/57). Also, GMT increased significantly from 0.014-2.172 IU/ML, after vaccination p=0.0001.Sero conversion and GMT are significantly high after the first MMR given at 12 months and this is supported by the surveillance data in Qassim.

To evaluate immune protection against vaccine-preventable diseases targeted by the Expanded Program of Immunization in Saudi Arabia.The study was carried out from September 2001 to February 2002. Using multistage sampling techniques, samples were collected from 5 regions of Saudi Arabia and sent for laboratory assay from the following age groups; 50 samples at 12 months, 50 at 6 years, and 100 at 17 years. Sera were assayed for diphtheria, tetanus, and pertussis. Sero neutralization was used for anti-diphtheria antibody assay, while enzyme linked immunoassay was used for anti-tetanus, anti-filament hemoagglutination (anti-FHA), and anti-pertussis titer (anti-PT) antibody assay.This survey showed that 100% of children had protection levels (/=0.01 IU/ml) against diphtheria at one year, 100% at 6 years, and 93.7% at 17 years. For tetanus, 95.9% had protection levels (/=0.1 IU/ml) at one year, 100% at 6 years, and 98.9% at 17 years. The geometric mean titer (GMT) of anti-FHA is 22 at one year, 29 at 6 years, and 24 IU/ml at 17 years, while the GMT of anti-PT is 36 at one year, 18 at 6 years, and 11 IU/ml at 17 years.Children at one, 6, and 17 years are well protected against diphtheria, pertussis, and tetanus.

A serosurvey study to evaluate the proportion of children with antibodies against diseases targeted by the Expanded Program of Immunization in the Kingdom of Saudi Arabia.Using multistage sampling techniques, we collected samples and sent them for laboratory assay from the following age groups; 100 samples at 6 months, 12 months, 18 months, 6 years, 13 years, and 17 years. We conducted the study from September 2001 to February 2002. We assayed sera for measles, rubella, and mumps antibodies in the measles-mumps-rubella reference laboratory in Germany, using enzyme immunoassay and plaque neutralization (PN) as a backup test for equivocal and negative samples. We only carried out a backup test for measles samples.The age group of 6 months had the highest proportion with negative measles antibodies. After adding the backup test (PN), the proportions of children with protective measles antibody were; 64% at 6 months, 87% at 12 months, 91% at 18 months, 75% at 6 years, 96% at 13 years, and 98% at 17 years. Rubella antibody positivity rates (7 IU) were 28% at 6 months, 49% at 12 months, 97% at 18 months, 98% at 6 years, and 100% at 13 years. While positivity rates in mumps were 14% at 6 months, 29% at 12 months, 59% at 18 months, 64% at 6 years, and 75% at 13 years.The unexpected low proportion of children with protective level at 6 years, despite being vaccinated with 2 measle doses is an important phenomenon. This reflects the interference between the first and the second measles dose. The Ministry of Health decided to conduct a catch up campaign targeting 1st through 3rd grade primary schools, who did not catch the mass campaign conducted in 2000. Also, this supports the decision taken by the ministry to change the measles immunization schedule to MMR at 12 months and a second dose at 6 years of age.

To compare the national growth monitoring data with the National Centre for Health Statistics (NCHS) growth standards, which is currently used in the Kingdom of Saudi Arabia (KSA).A cross sectional study following World Health Organization criteria in determining sample size was adopted, whereby 24,000 children from 5 regions were selected to be the desired sample. One hundred and two Primary Health Care centers were also selected randomly from the 5 regions, from where the sample was drawn. A special questionnaire was designed for the data collection. A pilot study was carried out to test the study instruments. Weight, height and head circumference were measured by standard procedures. This data was compared with the National Centre for Health Statistics (NCHS) data.The total number of children examined was 23,821, 11,913 boys and 11,908 girls, they were drawn from 102 health centers selected randomly. Comparing different percentiles for Saudi and NCHS data, there was a significant difference between the Saudi and American children.In order to ensure a correct follow up for our children in KSA, the national figures are more appropriate to follow than the NCHS data.

To evaluate the measles-mumps-rubella vaccine campaign targeting primary school children in the Kingdom of Saudi Arabia during the months of January and February 2000.Pre and post measles-mumps-rubella vaccine blood samples were collected from 54 children from the first grade and 96 children from the 6th grade. Antibodies against measles, mumps and rubella were assayed using enzyme immunoassay and a backup test of plaque neutralization test. This assay was carried out at the Reference Center, Koch Institute, Berlin, Germany.When the backup test results were added, 96%-98% of children had protection level against measles before the campaign. It is interesting to notice that pre-vaccination measles mean titer and positivity rate with enzyme linked immunoassay in the first grade were significantly lower than the 6th grade. One hundred percent and 96.8% were positive for rubella antibody before the campaign, in the first and 6th grades. Seventy-seven percent and 67% were positive for mumps before the campaign, in the first and 6th grade. After the measles-mumps-rubella vaccine campaign, protection rate reached 100% for the 3 antigens with a statistically significant boosting effect and increase in geometric mean of the titre.Measles-mumps-rubella vaccine campaign was effective in increasing protective levels and boosting antibodies against the 3 targeted diseases which can prevent epidemics in the primary schools.