In this study, stability of a landing gear mechanism with torsional degree of freedom is analyzed. Derivation of the equations of motion of the model with torsional degree of freedom and the von Schlippe tire model are presented. Nonlinear model is linearized and Routh-Hurwitz criterion is applied. Stability analysis is conducted in the e-v plane for different values of the torsional spring rate c and in the k-v plane for different values of the relaxation length σ and vertical force Fz . Percentages of the stable regions are computed. Effects of the variation of the caster length e, half contact length a and their ratio on stable regions are analyzed. Results and conclusions about the variation of stability are presented and constructive recommendations are given.

In the present work an H∞ -control technique is presented in concise form and applied to the design of discrete optimal multirate-output controllers. The technique used is based on multirate-output controllers having a multirate sampling mechanism with different sampling period in each measured output quantity of the system. It relies mainly, under appropriate conditions, on the reduction of the original H∞ -disturbance attenuation problem to an associated discrete H∞ -control problem for which a fictitious static state feedback controller is to be designed, even though some state variables may not be available (measurable) for feedback purposes. The discrete linear open-loop system model under consideration (which includes a disturbance term) is systematically derived from the associated continuous 3th-order MIMO linearized open-loop model of a practical power system, having an 160ΜVΑ synchronous generator supplying power to an infinite grid through a step-up transformer and an appropriate transmission line. Through the obtained pertinent simulation results the validity and practical usefulness of this design control technique is assessed.

The theory of “Relativistic Elasticity” is proposed for the design of the new generation large aircrafts with turbojet engines and speeds in the range of 50,000 km/h. This theory shows that there is a considerable difference between the absolute stress tensor and the stress tensor of the moving frame even in the range of speeds of 50,000 km/h. For bigger speeds like c/3, c/2 or 3c/4 (c=speed of light), the difference between the two stress tensors is very much increased. Therefore, for the next generation spacecrafts with very high speeds, then the relative stress tensor will be very much different than the absolute stress tensor. Furthermore, for velocities near the speed of light, the values of the relative stress tensor are very much bigger than the corresponding values of the absolute stress tensor. The proposed theory of “Relativistic Elasticity” is a combination between the theories of "Classical Elasticity" and "Special Relativity" and results to the “Universal Equation of Elasticity”. For the structural design of the new generation aircrafts and spacecrafts the stress tensor of the airframe will be used in combination to the singular integral equations method. Such a stress tensor is reduced to the solution of a multidimensional singular integral equation and for its numerical evaluation will be used the Singular Integral Operators Method (S.I.O.M.).

The determination of heavy metal ions are limited by two difficulties, very low concentration of heavy metal ions which may be lower than the detection limit of many traditional analytical techniques such as atomic absorption spectrometry, colorimetric, and voltametry. And the interfering effects of the matrix. Calcium silicate (CS) is obtained as mentioned in the literature, This synthesized material, which have many applications in various walks of life will be under study in this research. In a new area of the most important areas of life and the environment, a water treatment and removal of some heavy ions such as Mn+2 and Fe+3 ions present in waste water and underground water were efficiently removed by (CS).

The failure of some national projects AXES to expected results. According to experts one of the reasons is the lack of adequate theoretical apparatus for generating high-branching processes, unjustified detraction of opportunities enumerative models representative of AXES, which have their own laws paralleling computing, can not be reduced to algorithmic rules. This fact determines the need to develop innovative approaches to problem solving and organization of AXES interrelated levels of system design symbolic computation, from the linguistic level to the appropriate software and appropriate hardware level.

The extent of pollution of Imo, Utaewa Rivers and Essene Creek being sources of drinking water were assessed due to the smelting activities of the Aluminium Smelter at Ikot Abasi City, Nigeria. Soil and plants samples in the field near the water bodies were equally assessed. The physicochemical parameters investigated on all sampled water bodies were within the WHO and USEPA limits for drinking water with the exception of salinity, turbidity, TDS and few heavy metals (Mn, Fe, Al, Pb). The overall average levels of these parameters were 7.6±2.8 % (salinity), 16±12 FTU (Turbidity), 793±250 mg/L (TDS), 2.59±0.48 mg/L (Mn), 0.49±0.27 mg/L (Al) and 0.85±0.43 mg/L (Pb). Principal component biplot revealed strong and positive metal loadings whose ranges were (1.284−1.687), (0.499−0.515) and (0.959−1.630) for Essene Creek, Imo River and Utaewa River respectively. Similarly, clauster analysis showed that elemental compositions of soil and plants in the vicinity of aluminium smelter were traceable to the smelting activities. Also, accumulation of airborne particle by vegetation and surface soil was resulted from the activities in the smelting site. Al (1830−2170 μg/g) and Zn (141−147 μg/g) were more abundant at 0-5 cm soil depth than other metals (Cd, Mn, Ni, Fe, Pb, Co). Bioccumulation results revealed increased metal uptake by Vernonia amygdalia (Bitter leaves), Manihot esculenta (Cassava) and Carica papaya (Paw-paw) at the sites closest to the industry, hence can be used as good biomarkers for soil pollution.

Software security and protection plays an important role in software engineering. Considerable attempts have been made to enhance the security of the computer systems because of various available software piracy and virus attacks. Preventing attacks of software will have a huge influence on economic development. Thus, it is very vital to develop approaches that protect software from threats. There are various threats such as piracy, reverse engineering, tampering etc., exploits critical and poorly protected software. Thus, thorough threat analysis and new software protection schemes, needed to protect software from analysis and tampering attacks becomes very necessary. Various techniques are available in the literature for software protection from various attacks. This paper analyses the various techniques available in the literature for software protection. The functionalities and the characteristic features are various software protection techniques have been analyzed in this paper. The main goal of this paper is to analyze the existing software protection techniques and develop an efficient approach which would overcome the drawbacks of the existing techniques.

Data on genome structural and functional features for various organisms are being accumulated and analyzed in laboratories all over the world. The data are stored and analyzed on a large variety of expert systems. The public access to most of these data offers to scientists around the world an unprecedented chance to data mine and explores in depth this extraordinary information repository, trying to convert data into knowledge. The DNA and RNA molecules are symbolic sequences of amino acids in the corresponding proteins has definite advantages in what concerns storage, search, and retrieval of genomic information. In this study an attempt is made to develop an algorithm for aligning multiple DNA / protein sequences. In this process hotspots are located in a protein sequence using the multiple sequence alignment.

This paper proposes a robust H-infinity control design of a single unit differential type Wheeled Mobile Robot. Mobile robots are non holonomic systems as their constraint equations are not integrable. Considering the constraints and combining the kinematics and dynamics of the system, a linearized model is obtained. Taking into account the exogenous inputs in the form of model uncertainties and output disturbances, the augmented plant is formulated. The Hinfinity controller is designed such that the sensitivity of the closed loop system is minimised. The proposed design renders a robust controller such that the closed loop system is internally stable and the effect of disturbances and model uncertainties on some of the outputs is attenuated. Simulation results showing asymptotic stability plot, disturbance response and Robust Stability and Performance margins are found to be satisfactory.

Electron cyclotron (EC) absorption in tokamak plasma is based on interaction between wave and electron cyclotron movement when the electron passes through a layer of resonance at a fixed frequency and dependent magnetic field. This technique is the principle of additional heating (ECRH) and the generation of non-inductive current drive (ECCD) in modern fusion devices. In this paper we are interested by the problem of EC absorption which used a microscopic description of kinetic theory treatment versus the propagation which used the cold plasma description. The power absorbed depends on the optical depth which in turn depends on coefficient of absorption and the order of the excited harmonic for O-mode or X-mode. There is another possibility of heating by dissipation of Alfven waves, based on resonance of cold plasma waves, the shear Alfven wave (SW) and the compressional Alfven wave (FW). Once the (FW) power is coupled to (SW), it stays on the magnetic surface and dissipates there, which is cause the heating of bulk plasmas. This present calculation allows us to compare the two heating systems.