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Articles by Charles A. Osheku

The utilization of biomass for heat and power generation has aroused the interest of most researc... more The utilization of biomass for heat and power generation has aroused the interest of most researchers especially those of energy .In converting solid fuel to a usable form of energy, pyrolysis plays an integral role. Understanding this very important phenomenon in the thermochemical conversion processes and representing it with appropriate mathematical models is vital in the design of pyrolysis reactors and biomass gasifiers. Therefore, this study presents analytical solutions to the kinetic and the heat transfer equations that describe the slow pyrolysis of a biomass particle. The effects of Biot number, temperature and residence time on biomass particle decomposition were studied. The results from the proposed analytical models are in good agreement with the reported experimental results. The developed analytical solutions to the heat transfer equations which have been stated to be " analytically involved " showed average percentage error and standard deviations 0.439 and 0.103 from the experimental results respectively as compared with previous model in literature which gives average percentage error and standard deviations 0.75 and 0.106 from the experimental results respectively. This work is of great importance in the design of some pyrolysis reactors/units and in the optimal design of the biomass gasifiers.

The utilization of biomass for heat and power generation has aroused the interest of most researc... more The utilization of biomass for heat and power generation has aroused the interest of most researchers especially those of energy .In converting solid fuel to a usable form of energy, pyrolysis plays an integral role. Understanding this very important phenomenon in the thermochemical conversion processes and representing it with appropriate mathematical models is vital in the design of pyrolysis reactors and biomass gasifiers. Therefore, this study presents analytical solutions to the kinetic and the heat transfer equations that describe the slow pyrolysis of a biomass particle. The effects of Biot number, temperature and residence time on biomass particle decomposition were studied. The results from the proposed analytical models are in good agreement with the reported experimental results. The developed analytical solutions to the heat transfer equations which have been stated to be "analytically involved" showed average percentage error and standard deviations 0.439 and 0.103 from the experimental results respectively as compared with previous model in literature which gives average percentage error and standard deviations 0.75 and 0.106 from the experimental results respectively. This work is of great importance in the design of some pyrolysis reactors/units and in the optimal design of the biomass gasifiers.

Nomenclature L 1 =Length of the first stage of the rocket L 2 =Length of the second of the rocket... more Nomenclature L 1 =Length of the first stage of the rocket L 2 =Length of the second of the rocket L 3 =Length of the third stage of the rocket L n =Length of the first stage of the rocket m p1 =Initial mass of the propellant of the first stage m p2 =Initial mass of the propellant of the second stage m p3 =Mass of the payload (parabolic nose-cone) T 1 =Thrust of the 1 st stage I sp_1 =Specific impulse of the 1 st stage in sec T 2 =Thrust of the 2 nd stage I sp_2 =Specific impulse of the 2 nd stage in sec T 3 =Thrust of the 3 rd stage I sp_3 =Specific impulse of the 3 rd stage in sec Citation: Lanre AMA, Fashanu TA, Charles OA (2014) Parameterization of Micro Satellite Launch Vehicle. J Aeronaut Aerospace Eng 3: 134.

A longitudinally disturbed motion of a UAV after an arbitrary initial disturbance consists normal... more A longitudinally disturbed motion of a UAV after an arbitrary initial disturbance consists normally of two oscillatory modes: the short-period oscillation and the phugoid oscillation.The typical longitudinal model of a UAV in state-space can be separated into short-period mode and phugoid period mode equations of motion. In this study, we choose to investigate the dynamic characteristics of the longitudinal dynamic equation of a mini-UAV and its reduced forms popularly known as short-period and phugoid period modes. This is necessary to establish a basis for plant selection during PID autopilot design. The short and phugoid period oscillations modes are sieved from the longitudinal dynamic equation and carry the same eigenvalues of the longitudinal model, but they still differ. Firstly, the three systems have different step response trajectories due to their different DC gain values. Secondly, the variables that constitute the short-period and phugoid mode dynamic equations can be identified by their settling time after designing PID controllers. Statespace model of the longitudinal dynamics, phugoid mode and short period dynamics of a UAV can Aliyu et al.; AIR, 5(3): 1-13, 2015; Article no.AIR.18334 2 be transformed into equivalent transfer functions. These transfer functions are then used in the design of Proportional, Integral and Derivative (PID) controllers. Hence, the phugoid mode variables are the system variables in the longitudinal dynamic model with the longest settling time.

A theory governing the exural vibration of a conducting two-layer sandwich homogeneous elastic be... more A theory governing the exural vibration of a conducting two-layer sandwich homogeneous elastic beam in a transverse magnetic 5 eld is presented. The physics driving this problem derives from an energy dissipation mechanism through press-t joints in structural lami-6 nates. Recent advances made in the mechanics of sandwich-layered structures have shown that by simulating an environment of nonuniform 7 interface pressure, structural vibration can be attenuated signicantly. Equations of mathematical physics governing the stresses and the struc-8 tural vibration are derived via a laminated beam theory employing the Newtonian form of Cauchy's stress equations. By restricting mathemati-9 cal analysis to the case of cantilever architecture, a closed-form polynomial expression is derived for the system response. In particular, the 10 effects of magnetoelasticity, material conductivity, and interfacial pressure gradient on the response characteristics are demonstrated for design 11 analysis and engineering applications. It is shown via integral transforms that each mode of vibration is governed by a two-dimensional family of 12 natural frequency. For special and limit cases, recent theoretical and experimental results are validated from the theory reported in this paper.

This paper explores the application of a novel Linear Quadratic Gaussian (LQG) control synthesis ... more This paper explores the application of a novel Linear Quadratic Gaussian (LQG) control synthesis for an autopilot on the longitudinal flight dynamics of a fixed-wing, Unmanned Aerial Vehicle (UAV). Modelling results for the small UAV are presented and numerical values of the aerodynamic derivatives are computed via the DIGITAL DATCOM ® software.

In this paper, the mud-fluid-structure interaction mechanics for a deep offshore riser subject to... more In this paper, the mud-fluid-structure interaction mechanics for a deep offshore riser subject to internal and circulating external flows is investigated as a boundary value mathematical physics problem. The driving physics is premised on the kinematics of vortex-induced fully-developed compressible flow. For this problem, the deep offshore riser is idealized as a gas-carrying elastic column using Euler-Bernoulli beam theory. Notably, the subjective vortex flow arising from ocean water effect is considered as a shake-off phenomenon propelled by internal and external flows. It is also shown that the stochastic condition is central to the formation of vortex-induced vibration. By applying integral transforms on the resulting boundary value problem, modal vibration responses of the entire system are analyzed for design applications.

In this paper, the 3 degree of freedom (3DOF) simulation of the basic flight parameters of a sing... more In this paper, the 3 degree of freedom (3DOF) simulation of the basic flight parameters of a single stage sounding rocket developed at the Centre for Space Transport and Propulsion is discussed. The purpose of a lauching a sounding rocket rocket at the centre is to place a payload to a particular altitude. In order to determine the accuracy of getting to a targeted altitude using a particular rocket, a model of the system has to be developed. This model reduces the time and cost of making different prototypes of the rocket. The Centre for Space Transport and Propulsion designed a 3DOF model in the Matlab and Simulink environment to simulate the flight trajectory of the rocket TMR-1A. The results obtained via simulation are compared with the real parameters obtained via the onboard data acquisition system, to determine the integrity of the model used for the study. The model showed high degree of accuracy when simulated results are compared with real experimental data. However it was observed that the integrity of the model is affected by the accuracy of the value of drag coefficient, hence future work can be focused on more accurate determination of the drag coefficient.

A major application of solid propellants is in gun propulsion systems and rockets. The performanc... more A major application of solid propellants is in gun propulsion systems and rockets. The performance of a rocket depends greatly on the design of the solid propellant that meets a specific mission. Performance characteristics such as the burn time, burn rate, average thrust, specific impulse, characteristic velocity, etc., are basic design parameters that will determine the nature of the Original Research Article

The development of mathematical models for describing the dynamic behaviours of fluid conveying p... more The development of mathematical models for describing the dynamic behaviours of fluid conveying pipes, micro-pipes and nanotubes under the influence of some thermo-mechanical parameters results into nonlinear equations that are very difficult to solve analytically. In cases where the exact analytical solutions are presented either in implicit or explicit forms, high skills and rigorous mathematical analyses were employed. It is noted that such solutions do not provide general exact solutions. Inevitably, comparatively simple, flexible yet accurate and practicable solutions are required for the analyses of these structures. Therefore, in this study, approximate analytical solutions are provided to the nonlinear equations arising in flow-induced vibration of pipes, micro-pipes and nanotubes using Galerkin-Newton-Harmonic Method (GNHM). The developed approximate analytical solutions are shown to be valid for both small and large amplitude oscillations. The accuracies and explicitness of these solutions were examined in limiting cases to establish the suitability of the method.

This paper presents an integral transform analytic solution to the equations governing a fluid-co... more This paper presents an integral transform analytic solution to the equations governing a fluid-conveying pipeline segment where a gyroscopic or Coriolis force effect is taken into consideration. The mathematical model idealizes a segment of the pipeline as an elastic beam conveying an incompressible fluid. It is clearly shown that when such a system is supported at both ends and in a free motion, the Coriolis force dissipates no energy (or simply does not work) as it generates conjugate complex vibratory components for all flow velocities. It is demonstrated that the modal natural frequencies can be computed from the algebraic products of the complex frequency pairs. Clearly, the patterns of the characteristics of the system's natural frequencies are seen partly when the real and imaginary components are plotted, as widely seen in the literature. Nonetheless, results from this study revealed that a continuity profile exists to connect the subcritical, critical, and postcritical vibratory behaviours when the absolute values are plotted for any velocity. In the meantime, the efficacy and versatility of this method against the usual assumed spatial or temporal modal solutions are demonstrated by confirming the predictions and validity of results of earlier workers such as Paidoussis, Ziegler, and others where pre-and postdivergence behaviours are exhibited.

Stiff Ordinary Differential Equations (SODEs) are present in engineering, mathematics, and scienc... more Stiff Ordinary Differential Equations (SODEs) are present in engineering, mathematics, and sciences. Identifying them for effective simulation (or prediction) and perhaps hardware implementation in aerospace control systems is imperative. This paper considers only linear Initial Value Problems (IVPs) and brings to light the fact that stiffness ratio or coefficient of a suspected stiff dynamic system can be elusive as regards the phenomenon of stiffness. Though, it gives the insight suggesting stiffness when the value is up to 1000 but is not necessarily so in all ODEs. Neither does a value less than 1000 imply non-stiffness. MATLAB/Simulink ® and MAPLE ® were selected as the Problem Solving Environment (PSE) largely due to the peculiar attribute of Model Based Software Engineering (MBSE) and analytical computational superiority of each PSEs, respectively. This creates the base for comparing results from both numerical and analytical standpoint. In Simulink, two methods of modelling ODEs are presented. Experimenting with all the variable-step solvers in MATLAB ® ODE Suit for selected examples was carried out. Results point to the fact that stiffness coefficient of about 1000does not always suggest that an ODE is stiff nor does a value less than 1000 suggest non-stiff.

Electric drives are very useful in propelling the wheels of hybrid and electric vehicles (HEVs). ... more Electric drives are very useful in propelling the wheels of hybrid and electric vehicles (HEVs). They also play a central function in the electric power steering (EPS). In this paper, a loss minimizing scheme for permanent magnet synchronous motor (PMSM) was derived analytically and takes into consideration copper, iron and stray losses. The proposed scheme is better than applying look-up tables and online search methods because it saves memory cost and is not limited by bandwidth constraints. Current control was achieved by the internal model control method. The performance of the resulting control scheme was simulated and was found to improve the efficiency of the EPS system. Keywords-Loss minimization, permanent magnet synchronous motor (PMSM), internal model control (IMC), electric power steering (EPS).

There is a continuous demand for high performance composite propellant formulations to meet missi... more There is a continuous demand for high performance composite propellant formulations to meet mission requirements. The performance of composite propellant formulations can be enhanced by optimizing propellant formulation. However, the main objective of this study is to formulate a composition for composite propellant by optimizing the specific impulse which is the measure of propellant performance. A central composite design (ccd) consisting five ingredients (ammonium nitrate, powdered aluminum, polyester resin, ammonium dichromate and powdered charcoal) at five levels was used to formulate optimum propellant formulation from composite materials of ammonium nitrate based propellant verified for propellant characteristics using propellant performance evaluation programme (propep 3). The responses evaluated are specific impulse, characteristic velocity, density, temperature and molecular weight. Response surface methodology was used to analyze the results of the ccd of the composite formulations. The optimum values for specific impulse, characteristic velocity, density, temperature and molecular weight of the mixture from the surface plot are 212.178 s, 1335.81 m/s, 1640.6 k g/m3, 1968.73 k and 21.7722 g/mol respectively. The optimum predicted specific impulse was 212.178 s at composite composition of 73.61% ammonium nitrate, 4.36% powdered aluminum, 14.39% polyester resin, 5.10% ammonium dichromate and 2.54% powdered charcoal. The propellant optimum composition validated with propep 3 are in good agreement with each other in their accompany propellant characteristics. Therefore, the optimal propellant formulation enhanced the performance of solid propellants.

Oil and Gas Pipelines consists of pipes, compressors and pumps. These are frequently located in e... more Oil and Gas Pipelines consists of pipes, compressors and pumps. These are frequently located in environments that are difficult to monitor and secure (e.g., creeks and remote areas). Attacks or damage to such installations can lead to enormous ecological impact and loss of revenue. Developing and implementing monitoring systems that can continuously assess the state and condition of oil and gas pipelines is very essential. Current solutions for monitoring such facilities are very manual and risky. Unmanned Aerial Vehicle (UAV) offers great new alternative solutions. In this study, we present a conceptual design of a UAV with a battery powered propulsion system for such application. Here, we show by example how a mission statement can be translated into a physical aircraft from first principle. Notably, five (5) novel mathematical equations were formulated to aid and optimise the design process. These novel equations basically relate the takeoff mass of the aircraft with the wingspan, chord length and fuselage length. With such equations, for a designed takeoff mass, there exist several variant of the aircraft concept by varying wingspan, chord length and fuselage length of the UAV. In addition, we used thrust-to-weight ratio in a novel approach to ensure that the power available at the propeller will be sufficient for the mission. For this phase of the design, the basic objective among others is to attain lift-off at a very short take off distance. The method proposed in this study proved to be very effective after several successful flight tests.

Conferences by Charles A. Osheku

A low cost ground test system was designed with embedded systems at the core. Remote ignition of ... more A low cost ground test system was designed with embedded systems at the core. Remote ignition of the solid rocket motor was implemented via a short message service (SMS) controlled switch. A microcontroller circuit was included to abort activation and a load-cell interfaced with a data acquisition system was used to record thrust generated by the thrust chamber of a solid rocket motor. The approach to obtaining thrust measurements is discussed and results are presented. The maximum thrust measured from the experiment was 1970.5N and the system has the capability to measure thrust values up to 5000N.

Books by Charles A. Osheku

The utilization of biomass for heat and power generation has aroused the interest of most researc... more The utilization of biomass for heat and power generation has aroused the interest of most researchers especially those of energy .In converting solid fuel to a usable form of energy, pyrolysis plays an integral role. Understanding this very important phenomenon in the thermochemical conversion processes and representing it with appropriate mathematical models is vital in the design of pyrolysis reactors and biomass gasifiers. Therefore, this study presents analytical solutions to the kinetic and the heat transfer equations that describe the slow pyrolysis of a biomass particle. The effects of Biot number, temperature and residence time on biomass particle decomposition were studied. The results from the proposed analytical models are in good agreement with the reported experimental results. The developed analytical solutions to the heat transfer equations which have been stated to be "analytically involved" showed average percentage error and standard deviations 0.439 and 0.103 from the experimental results respectively as compared with previous model in literature which gives average percentage error and standard deviations 0.75 and 0.106 from the experimental results respectively. This work is of great importance in the design of some pyrolysis reactors/units and in the optimal design of the biomass gasifiers.