This research study investigates preventive maintenance management of diesel engine generators at the Nigerian Maritime Academy, Oron. An optimization methodology taking cognisance of equipment age was applied on failure data of diesel engine generators obtained from the institution’s maintenance data base to provide cost effective maintenance management / replacement programme for critical components of diesel engine generators. The analyzed results using Matlab provides a cost and reliability template which can be used to perform diesel generator maintenance management programme in the academy.
AN EFFICIENT HEURISTIC ALGORITHM FOR FLEXIBLE JOB SHOP SCHEDULING WITH MAINTE...mathsjournal
This paper deals with the flexible job shop scheduling problem with the preventive maintenance constraints where the objectives are to minimize the overall completion time (makespan), the total workload of machines and
the workload of the most loaded machine. A fast heuristic algorithm based on a constructive procedure is developed to solve the problem in very short time. The algorithm is tested on the benchmark instances from the
literature in order to evaluate its performance. Computational results show that, the proposed heuristic method is computationally efficient and promising for practical problems.
Permanent magnet direct current motors (PMDCM) are widely used in various applications such as space technologies, personal computers, medical, military, robotics, electrical vehicles, etc. In this paper, the mathematical model of PMDCM is designed and simulated using MATLAB software. The PMDCM speed is controlled using rate feedback controller due to its ability of improving system damping. To improve the controller performance, it’s parameters are tuned using genetic algorithm (GA) and direct search (DS) techniques. The tuning process based on different performance criteria. The most four common performance criteria used in this paper are JIAE (Integral of Absolute Error), JISE (Integral of Square Error), JITAE (Integral of Time-Weighted Absolute Error), and JITSE (Integral of Time-Weighted Square Error). The results obtained from these evolutionary techniques are compared. The results show an obvious improvement in system performance including enhancing the transient and steady state of PMDCM speed responses for all performance criteria.
Estimation of motor inertia and friction components is a complex and challenging task in motion control applications where small size DC motors (<100W) are used for precise control. It is essential to estimate the accurate friction components and motor inertia, because the parameters provided by the manufacturer are not always accurate. This research proposes a Sensorless method of determining DC motor parameters, including moment of inertia, torque coefficient and frictional components using the Disturbance Observer (DOB) as a torque sensor. The constant velocity motion test and a novel Reverse Motion Acceleration test were conducted to estimate frictional components and moment of inertia of the motor. The validity of the proposed novel method was verified by experimental results and compared with conventional acceleration and deceleration motion tests. Experiments have been carried out to show the effectiveness and viability of the estimated parameters using a Reaction Torque Observer (RTOB) based friction compensation method.
The problem of controlling an unstable delayed double integrating process with fractional delay using a
feed forward first-order lag-lead compensator is studied. The effect of time delay of the process in a range between
0.1 and 0.9 seconds is considered. The compensator is tuned using MATLAB optimization toolbox with five forms
of the objective function in terms of the error between the step time response of the closed-loop control system and
the response steady-state value. Using the proposed compensator with the fractional delayed double integrating
process indicates the robustness of the compensator in the time delay range used with superior time-based
specifications compared with other technique based on PID controller.
Keywords — Delayed double integrating process with fractional delay, Feed forward lag-lead first-order
compensator, compensator tuning, MATLAB optimization toolbox, Control system performance.
OPTIMAL PID CONTROLLER DESIGN FOR SPEED CONTROL OF A SEPARATELY EXCITED DC MO...ijscmcjournal
This paper presents a new approach to determine the optimal proportional-integral-derivative controller
parameters for the speed control of a separately excited DC motor using firefly optimization technique.
Firefly algorithm is one of the recent evolutionary methods which are inspired by the Firefly’s behavior in
nature. The firefly optimization technique is successfully implemented using MATLAB software. A
comparison is drawn from the results obtained between the linear quadratic regulator and firefly
optimization techniques. Simulation results are presented to illustrate the performance and validity of the
design method.
AN EFFICIENT HEURISTIC ALGORITHM FOR FLEXIBLE JOB SHOP SCHEDULING WITH MAINTE...mathsjournal
This paper deals with the flexible job shop scheduling problem with the preventive maintenance constraints where the objectives are to minimize the overall completion time (makespan), the total workload of machines and
the workload of the most loaded machine. A fast heuristic algorithm based on a constructive procedure is developed to solve the problem in very short time. The algorithm is tested on the benchmark instances from the
literature in order to evaluate its performance. Computational results show that, the proposed heuristic method is computationally efficient and promising for practical problems.
Permanent magnet direct current motors (PMDCM) are widely used in various applications such as space technologies, personal computers, medical, military, robotics, electrical vehicles, etc. In this paper, the mathematical model of PMDCM is designed and simulated using MATLAB software. The PMDCM speed is controlled using rate feedback controller due to its ability of improving system damping. To improve the controller performance, it’s parameters are tuned using genetic algorithm (GA) and direct search (DS) techniques. The tuning process based on different performance criteria. The most four common performance criteria used in this paper are JIAE (Integral of Absolute Error), JISE (Integral of Square Error), JITAE (Integral of Time-Weighted Absolute Error), and JITSE (Integral of Time-Weighted Square Error). The results obtained from these evolutionary techniques are compared. The results show an obvious improvement in system performance including enhancing the transient and steady state of PMDCM speed responses for all performance criteria.
Estimation of motor inertia and friction components is a complex and challenging task in motion control applications where small size DC motors (<100W) are used for precise control. It is essential to estimate the accurate friction components and motor inertia, because the parameters provided by the manufacturer are not always accurate. This research proposes a Sensorless method of determining DC motor parameters, including moment of inertia, torque coefficient and frictional components using the Disturbance Observer (DOB) as a torque sensor. The constant velocity motion test and a novel Reverse Motion Acceleration test were conducted to estimate frictional components and moment of inertia of the motor. The validity of the proposed novel method was verified by experimental results and compared with conventional acceleration and deceleration motion tests. Experiments have been carried out to show the effectiveness and viability of the estimated parameters using a Reaction Torque Observer (RTOB) based friction compensation method.
The problem of controlling an unstable delayed double integrating process with fractional delay using a
feed forward first-order lag-lead compensator is studied. The effect of time delay of the process in a range between
0.1 and 0.9 seconds is considered. The compensator is tuned using MATLAB optimization toolbox with five forms
of the objective function in terms of the error between the step time response of the closed-loop control system and
the response steady-state value. Using the proposed compensator with the fractional delayed double integrating
process indicates the robustness of the compensator in the time delay range used with superior time-based
specifications compared with other technique based on PID controller.
Keywords — Delayed double integrating process with fractional delay, Feed forward lag-lead first-order
compensator, compensator tuning, MATLAB optimization toolbox, Control system performance.
OPTIMAL PID CONTROLLER DESIGN FOR SPEED CONTROL OF A SEPARATELY EXCITED DC MO...ijscmcjournal
This paper presents a new approach to determine the optimal proportional-integral-derivative controller
parameters for the speed control of a separately excited DC motor using firefly optimization technique.
Firefly algorithm is one of the recent evolutionary methods which are inspired by the Firefly’s behavior in
nature. The firefly optimization technique is successfully implemented using MATLAB software. A
comparison is drawn from the results obtained between the linear quadratic regulator and firefly
optimization techniques. Simulation results are presented to illustrate the performance and validity of the
design method.
Optimization of Economic Load Dispatch with Unit Commitment on Multi MachineIJAPEJOURNAL
Economic load dispatch (ELD) and Unit Commitment (UC) are significant research applications in power systems that optimize the total production cost of the predicted load demand. The UC problem determines a turn-on and turn-off schedule for a given combination of generating units, thus satisfying a set of dynamic operational constraints. ELD optimizes the operation cost for all scheduled generating units with respect to the load demands of customers. The first phase in this project is to economically schedule the distribution of generating units using Gauss seidal and the second phase is to determine optimal load distribution for the scheduled units using dynamic programming method is applied to select and choose the combination of generating units that commit and de-commit during each hour. These precommitted schedules are optimized by dynamic programming method thus producing a global optimum solution with feasible and effective solution quality, minimal cost and time and higher precision. The effectiveness of the proposed techniques is investigated on two test systems consisting of five generating units and the experiments are carried out using MATLAB R2010b software. Experimental results prove that the proposed method is capable of yielding higher quality solution including mathematical simplicity, fast convergence, diversity maintenance, robustness and scalability for the complex ELD-UC problem.
Metaheuristics-based Optimal Reactive Power Management in Offshore Wind Farms...Aimilia-Myrsini Theologi
The aim of the thesis is to optimally coordinate the reactive power sources in offshore wind farms in a predictive manner based to the principle of minimizing the wind farm power losses, as well the variations of the transformers tap positions. First, an accurate Neural Network-based wind speed forecasting algorithm was developed in order to counteract the uncertainty of the wind and finally, the optimal management of the available reactive sources is tackled by a metaheuristics-based method. Two different cases were investigated: a far-offshore wind farm with HVDC interconnection link and the AC connected Dutch wind farm BORSSELE.
STABILIZATION AT UPRIGHT EQUILIBRIUM POSITION OF A DOUBLE INVERTED PENDULUM W...ijcsa
A double inverted pendulum plant has been in the domain of control researchers as an established model for studies on stability. The stability of such as a system taking the linearized plant dynamics has yielded satisfactory results by many researchers using classical control techniques. The established model that is analyzed as part of this work was tested under the influence of time delay, where the controller was fine tuned using a BAT algorithm taking into considering the fitness function of square of error. This proposed
method gave results which were better when compared without time delay wherein the calculated values
indicated the issues when incorporating time delay
The objective of the paper is to investigate the possibility of using a 2DOF controller in disturbance rejection associated with delayed double integrating processes. The effect of time delay of the process in a range between 0.1 and 0.9 seconds is considered. The controller is tuned using MATLAB optimization toolbox with three forms of the objective function in terms of the error between the step time response of the closed-loop control system and the desired zero value. Using the proposed controller with the fractional delayed double integrating process indicates the robustness of the controller in the time delay range used. The 2DOF controller is able to complete with the PID plus first-order lag controller , but it can not compete with other types of controllers such as the I-PD and PD-PI controllers..
Keywords — Delayed double integrating process, 2DOF controller, controller tuning, MATLAB optimization toolbox, Control system performance.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
Objective functions modification of GA optimized PID controller for brushed D...IJECEIAES
PID Optimization by Genetic Algorithm or any intelligent optimization method is widely being used recently. The main issue is to select a suitable objective function based on error criteria. Original error criteria that is widely being used such as ITAE, ISE, ITSE and IAE is insufficient in enhancing some of the performance parameter. Parameter such as settling time, rise time, percentage of overshoot, and steady state error is included in the objective function. Weightage is added into these parameters based on users’ performance requirement. Based on the results, modified error criteria show improvement in all performance parameter after being modified. All of the error criteria produce 0% overshoot, 29.51%-39.44% shorter rise time, 21.11%-42.98% better settling time, 10% to 53.76% reduction in steady state error. The performance of modified objective function in minimizing the error signal is reduced. It can be concluded that modification of objective function by adding performance parameter into consideration could improve the performance of rise time, settling time, overshoot percentage, and steady state error.
Design of GCSC Stabilizing Controller for Damping Low Frequency OscillationsIJAEMSJORNAL
This paper presents a systematic procedure for modeling and simulation of a power system equipped with FACTS type Gate Controlled Series Compensator (GCSC) based stabilizer controller. Single Machine Infinite Bus (SMIB) power system was investigated for evaluation of GCSC stabilizing controller for enhancing the overall dynamic system performance. PSO algorithm is employed to compute the optimal parameters of damping controller. Eigenvalues of system under various operating condition and nonlinear time domain simulation is employed to verify the effectiveness and robustness of GCSC stabilizing controller in damping low frequency oscillations (LFO) modes.
Impacts of Flooding on Road Transport Infrastructure In Enugu Metropolitan Ci...IJERA Editor
An assessment of the impact of flooding on the road transport infrastructure in Enugu Metropolis was carried out using survey research method. Thirty impact indicators were rated by the respondents against six impact dimensions of population, vulnerability of activities, frequency, intensity, extent and risk. Three null hypotheses were postulated and tested. One sample t-test was used for testing hypothesis one which stated that damages to the road transport infrastructure resulting from flooding are not significant to warrant mitigation.Since the p-value =0.000(p<0.05),>< 0.05), indicating high impact of flooding on the socio-economic activities in Enugu urban.Furthermore a statistically significant impact was equally recorded in hypothesis three since thecalculated p–value (0.000)was less than 0.05, (p < 0.05). The implication was that damages to road transport infrastructure due to flooding have significant impact on the environmental sustainability of the study area. The model generated hadGoodness of Fit Index (GFI) = 0.974; Adjusted Goodness of Fit Index (AGFI) = 0.951; Comparative Fit Index (CFI)= 0.949 and Incremental Fit Index (IFI) = 0.950; while the Root Mean Square Error of Approximation (RMSEA) = 0.059. The paper therefore recommendedproper infrastructural design and planning, good governance, population control and appropriate weather monitoring as some measures that could be adopted to mitigate the impact of flooding on the road transport infrastructure in Enugu Urban.
Experimental Study of an Atmospheric Pressure Dielectric Barrier Discharge an...IJERA Editor
A homogeneous dielectric barrier discharge (DBD) in argon was produced by applying high voltage A.C. source of potential difference (0-20) kV operating at a frequency of 10-30 kHz across two parallel plate electrodes with glass as dielectric barrier. The discharge was characterized by optical emission spectroscopy (OES) and electrical measurement. Four argon emission lines from the discharge were analyzed and the electron temperature was estimated by line intensity ratio method. The electron density in the discharge was estimated by power balance method. An investigation of the effect of inter-electrode distance on the electron density was made. The results showed that the electron temperature is less than 1 eV and the electron density is of the order of 1011cm-3 which varied with the inter electrode distance. Discharge was applied for surface modification of polyethylene terepthalate (PET). Modified surfaces were studied by contact angle measurement and FTIR spectroscopy.
Efficient Facial Expression and Face Recognition using Ranking MethodIJERA Editor
Expression detection is useful as a non-invasive method of lie detection and behaviour prediction. However, these facial expressions may be difficult to detect to the untrained eye. In this paper we implements facial expression recognition techniques using Ranking Method. The human face plays an important role in our social interaction, conveying people's identity. Using human face as a key to security, the biometrics face recognition technology has received significant attention in the past several years. Experiments are performed using standard database like surprise, sad and happiness. The universally accepted three principal emotions to be recognized are: surprise, sad and happiness along with neutral.
Conjugate Heat transfer Analysis of helical fins with airfoil cross-section a...IJERA Editor
Air Cooled Engines have been used in a variety of applications, ranging from airplanes to motorbikes and even stationary or portable engines. Since modern automobiles and airplanes use engines delivering more power, they have to be cooled more efficiently due to which a more complex water cooling system is used for cooling engines with large displacements. Hence air cooling is becoming a thing of the past, especially in the aviation sector due to the advent of more efficient gas turbine engines. However air cooled internal combustion engines are still being used in a wide variety of two-wheelers ranging from small single cylinder engines to heavy duty liter class V-twins and Inline fours, due to the non-practicalities associated with the installment of a bulky water cooling system in two-wheelers. So one can ascertain that there is a scope for improving the efficiency of air cooled engines even further. The objective of this paper is to analyze currently existing fin design employed in most of the air cooled engines and improve it by changing the cross-section to a streamlined one and also making the fins in a helical orientation as opposed to the regular circular fins employed. Our analysis comprises of a computational fluid dynamics study of both the fin models with identical dimensions and simulated in the same environment using ANSYS FLUENT 15 software and we attempt to compare their performance using the temperature and heat transfer coefficient distribution plots obtained.
Optimization of Economic Load Dispatch with Unit Commitment on Multi MachineIJAPEJOURNAL
Economic load dispatch (ELD) and Unit Commitment (UC) are significant research applications in power systems that optimize the total production cost of the predicted load demand. The UC problem determines a turn-on and turn-off schedule for a given combination of generating units, thus satisfying a set of dynamic operational constraints. ELD optimizes the operation cost for all scheduled generating units with respect to the load demands of customers. The first phase in this project is to economically schedule the distribution of generating units using Gauss seidal and the second phase is to determine optimal load distribution for the scheduled units using dynamic programming method is applied to select and choose the combination of generating units that commit and de-commit during each hour. These precommitted schedules are optimized by dynamic programming method thus producing a global optimum solution with feasible and effective solution quality, minimal cost and time and higher precision. The effectiveness of the proposed techniques is investigated on two test systems consisting of five generating units and the experiments are carried out using MATLAB R2010b software. Experimental results prove that the proposed method is capable of yielding higher quality solution including mathematical simplicity, fast convergence, diversity maintenance, robustness and scalability for the complex ELD-UC problem.
Metaheuristics-based Optimal Reactive Power Management in Offshore Wind Farms...Aimilia-Myrsini Theologi
The aim of the thesis is to optimally coordinate the reactive power sources in offshore wind farms in a predictive manner based to the principle of minimizing the wind farm power losses, as well the variations of the transformers tap positions. First, an accurate Neural Network-based wind speed forecasting algorithm was developed in order to counteract the uncertainty of the wind and finally, the optimal management of the available reactive sources is tackled by a metaheuristics-based method. Two different cases were investigated: a far-offshore wind farm with HVDC interconnection link and the AC connected Dutch wind farm BORSSELE.
STABILIZATION AT UPRIGHT EQUILIBRIUM POSITION OF A DOUBLE INVERTED PENDULUM W...ijcsa
A double inverted pendulum plant has been in the domain of control researchers as an established model for studies on stability. The stability of such as a system taking the linearized plant dynamics has yielded satisfactory results by many researchers using classical control techniques. The established model that is analyzed as part of this work was tested under the influence of time delay, where the controller was fine tuned using a BAT algorithm taking into considering the fitness function of square of error. This proposed
method gave results which were better when compared without time delay wherein the calculated values
indicated the issues when incorporating time delay
The objective of the paper is to investigate the possibility of using a 2DOF controller in disturbance rejection associated with delayed double integrating processes. The effect of time delay of the process in a range between 0.1 and 0.9 seconds is considered. The controller is tuned using MATLAB optimization toolbox with three forms of the objective function in terms of the error between the step time response of the closed-loop control system and the desired zero value. Using the proposed controller with the fractional delayed double integrating process indicates the robustness of the controller in the time delay range used. The 2DOF controller is able to complete with the PID plus first-order lag controller , but it can not compete with other types of controllers such as the I-PD and PD-PI controllers..
Keywords — Delayed double integrating process, 2DOF controller, controller tuning, MATLAB optimization toolbox, Control system performance.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
Objective functions modification of GA optimized PID controller for brushed D...IJECEIAES
PID Optimization by Genetic Algorithm or any intelligent optimization method is widely being used recently. The main issue is to select a suitable objective function based on error criteria. Original error criteria that is widely being used such as ITAE, ISE, ITSE and IAE is insufficient in enhancing some of the performance parameter. Parameter such as settling time, rise time, percentage of overshoot, and steady state error is included in the objective function. Weightage is added into these parameters based on users’ performance requirement. Based on the results, modified error criteria show improvement in all performance parameter after being modified. All of the error criteria produce 0% overshoot, 29.51%-39.44% shorter rise time, 21.11%-42.98% better settling time, 10% to 53.76% reduction in steady state error. The performance of modified objective function in minimizing the error signal is reduced. It can be concluded that modification of objective function by adding performance parameter into consideration could improve the performance of rise time, settling time, overshoot percentage, and steady state error.
Design of GCSC Stabilizing Controller for Damping Low Frequency OscillationsIJAEMSJORNAL
This paper presents a systematic procedure for modeling and simulation of a power system equipped with FACTS type Gate Controlled Series Compensator (GCSC) based stabilizer controller. Single Machine Infinite Bus (SMIB) power system was investigated for evaluation of GCSC stabilizing controller for enhancing the overall dynamic system performance. PSO algorithm is employed to compute the optimal parameters of damping controller. Eigenvalues of system under various operating condition and nonlinear time domain simulation is employed to verify the effectiveness and robustness of GCSC stabilizing controller in damping low frequency oscillations (LFO) modes.
Impacts of Flooding on Road Transport Infrastructure In Enugu Metropolitan Ci...IJERA Editor
An assessment of the impact of flooding on the road transport infrastructure in Enugu Metropolis was carried out using survey research method. Thirty impact indicators were rated by the respondents against six impact dimensions of population, vulnerability of activities, frequency, intensity, extent and risk. Three null hypotheses were postulated and tested. One sample t-test was used for testing hypothesis one which stated that damages to the road transport infrastructure resulting from flooding are not significant to warrant mitigation.Since the p-value =0.000(p<0.05),>< 0.05), indicating high impact of flooding on the socio-economic activities in Enugu urban.Furthermore a statistically significant impact was equally recorded in hypothesis three since thecalculated p–value (0.000)was less than 0.05, (p < 0.05). The implication was that damages to road transport infrastructure due to flooding have significant impact on the environmental sustainability of the study area. The model generated hadGoodness of Fit Index (GFI) = 0.974; Adjusted Goodness of Fit Index (AGFI) = 0.951; Comparative Fit Index (CFI)= 0.949 and Incremental Fit Index (IFI) = 0.950; while the Root Mean Square Error of Approximation (RMSEA) = 0.059. The paper therefore recommendedproper infrastructural design and planning, good governance, population control and appropriate weather monitoring as some measures that could be adopted to mitigate the impact of flooding on the road transport infrastructure in Enugu Urban.
Experimental Study of an Atmospheric Pressure Dielectric Barrier Discharge an...IJERA Editor
A homogeneous dielectric barrier discharge (DBD) in argon was produced by applying high voltage A.C. source of potential difference (0-20) kV operating at a frequency of 10-30 kHz across two parallel plate electrodes with glass as dielectric barrier. The discharge was characterized by optical emission spectroscopy (OES) and electrical measurement. Four argon emission lines from the discharge were analyzed and the electron temperature was estimated by line intensity ratio method. The electron density in the discharge was estimated by power balance method. An investigation of the effect of inter-electrode distance on the electron density was made. The results showed that the electron temperature is less than 1 eV and the electron density is of the order of 1011cm-3 which varied with the inter electrode distance. Discharge was applied for surface modification of polyethylene terepthalate (PET). Modified surfaces were studied by contact angle measurement and FTIR spectroscopy.
Efficient Facial Expression and Face Recognition using Ranking MethodIJERA Editor
Expression detection is useful as a non-invasive method of lie detection and behaviour prediction. However, these facial expressions may be difficult to detect to the untrained eye. In this paper we implements facial expression recognition techniques using Ranking Method. The human face plays an important role in our social interaction, conveying people's identity. Using human face as a key to security, the biometrics face recognition technology has received significant attention in the past several years. Experiments are performed using standard database like surprise, sad and happiness. The universally accepted three principal emotions to be recognized are: surprise, sad and happiness along with neutral.
Conjugate Heat transfer Analysis of helical fins with airfoil cross-section a...IJERA Editor
Air Cooled Engines have been used in a variety of applications, ranging from airplanes to motorbikes and even stationary or portable engines. Since modern automobiles and airplanes use engines delivering more power, they have to be cooled more efficiently due to which a more complex water cooling system is used for cooling engines with large displacements. Hence air cooling is becoming a thing of the past, especially in the aviation sector due to the advent of more efficient gas turbine engines. However air cooled internal combustion engines are still being used in a wide variety of two-wheelers ranging from small single cylinder engines to heavy duty liter class V-twins and Inline fours, due to the non-practicalities associated with the installment of a bulky water cooling system in two-wheelers. So one can ascertain that there is a scope for improving the efficiency of air cooled engines even further. The objective of this paper is to analyze currently existing fin design employed in most of the air cooled engines and improve it by changing the cross-section to a streamlined one and also making the fins in a helical orientation as opposed to the regular circular fins employed. Our analysis comprises of a computational fluid dynamics study of both the fin models with identical dimensions and simulated in the same environment using ANSYS FLUENT 15 software and we attempt to compare their performance using the temperature and heat transfer coefficient distribution plots obtained.
Chemical Looping Combustion of Rice HuskIJERA Editor
A thermodynamic investigation of direct chemical looping combustion (CLC) of rice husk is presented in this paper. Both steam and CO2 are used for gasification within the temperature range of 500–1200˚C and different amounts of oxygen carriers. Chemical equilibrium model was considered for the CLC fuel reactor. The trends in product compositions of the fuel reactor, were determined. Rice husk gasification using 3 moles H2O and 0 moles CO2 per mole carbon (in rice husk) at 1 bar pressure and 900˚C was found to be the best operating point for hundred percent carbon conversion in the fuel reactor. Such detailed thermodynamic studies can be useful to design chemical looping combustion processes using different fuels.
Experimental Test of Stainless Steel Wire Mesh and Aluminium Alloy With Glass...IJERA Editor
At present, composite materials are mostly used in aircraft structural components, because of their excellent properties like lightweight, high strength to weight ratio, high stiffness, and corrosion resistance and less expensive. In this experimental work, the mechanical properties of laminate, this is reinforced with stainless steel wire mesh, aluminum sheet metal, perforated aluminum sheet metal and glass fibers to be laminate and investigated. The stainless steel wire mesh and perforated aluminum metal were sequentially stacked to fabricate, hybrid composites. The aluminum metal sheet is also employed with that sequence to get maximum strength and less weight. The tensile, compressive and flexure tests carried out on the hybrid composite. To investigate the mechanical properties and elastic properties of the metal matrix composite laminate of a material we are using experimental test and theoretical calculation. The experimental work consists of Tensile, compressive and flexural test. The expectation of this project results in the tensile and compressive properties of this hybrid composite it is slightly lesser than carbon fibers but it could facilitate a weight reduction compared with CFRP panels. So this hybrid laminates composite material offering significant weight savings and maximum strength over some other GFRP conventional panels.
Radix-3 Algorithm for Realization of Type-II Discrete Sine TransformIJERA Editor
In this paper, radix-3 algorithm for computation of type-II discrete sine transform (DST-II) of length N =
3𝑚 (𝑚 = 1,2, … . ) is presented. The DST-II of length N can be realized from three DST-II sequences, each of
length N/3. A block diagram of for computation of the radix-3 DST-II algorithm is given. Signal flow graph for
DST-II of length 𝑁 = 32 is shown to clarify the proposed algorithm.
Effect of Harvest of Air Relative Humidity on Water and Heat Transfer in Soil...IJERA Editor
In this work, the main objective is to analyze the effect of the harvest of air relative humidity on soil temperature, soil water storage and evaporation. An experiment work was conducted in order to evaluate the quantity of soil water adsorbed by harvesting of relative air humidity. This experimental work was conducted on hilly areas with various hypsographic and microclimatic conditions greatly affecting daily fluctuations of air humidity and soil characteristics. The metrological data needed by SISPAT model were obtained by using a Campbell Scientific equipments Station recorder on data loggers every half hour. A numerical model based on SiSPAT (Système d’Interaction Sol Plante Atmosphère) formulation is adopted. The general equations of the proposed model are based on heat and mass transfer in the soil, atmosphere and plant system. This study shows that Soil Water Adsorption (SWA) induce an increasing in the total evaporation and in soil water storage especially on the upper layers. The effect of Soil Water Adsorption on soil temperature appears for the first layers of soil and become absent in the profound zone because the vapour condensation phenomenon is very important at night for the first layers.
Design and Implementation of programmable Cardiac Pacemaker Using VHDLIJERA Editor
Pacemaker design has evolved very rapidly over the last several years. There has been a great deal of work in enhancing the programmability of pacemakers, to enable them to be programmed to work with different selected operating parameters, and indeed to work in different modes. In Taiwan, about 70%of cardiac pacemakerpatients are paced only from the ventricle with some pacing parameter programmability. This paper goal is to design a cardiac pacemaker with various NBG modes. A state machine approach has been followed to achieve the desired purpose. The pacemaker system is divide into three main sections i.e. controlling unit, sensing unit and pulse generator. In this paper we mainly concentrate on controlling unit and pulse generator. It has been developed using VHDL coding and implemented in hardware using FPGA. In a simple pacemaker process i.e. single chamber or dual chamber pacemaker, first an input signal or an event is detected in heart through leads. When the input signal is detected a timer generates a delay for approximately 0.8 sec. It is the time between two consecutive heartbeats, thus giving us 72 heartbeats per minute. Once the generated delay expires, sensing unit again start detecting a new event. If any event is detected we repeat the process of detection and waiting. If no event is detected we need to provide an electrical pulse to the heart and then repeat the whole process of detection and waiting. The code has been optimized and modified for different pacemaker modes.
Effect of Process Parameters of Friction Stir Welded Joint for Similar Alumin...IJERA Editor
In this paper the effect of process parameters of friction stir welded joint for similar aluminium alloys H30 was studied. Taper cylindrical with three flutes all made of High speed steel was used for the friction stir welding (FSW) aluminium alloy H30 and the tensile test of the welded joint were tested by universal testing method. The optimization done using detailed mathematical model is simulated by Minitab17. In this investigation, an effective approach based on Taguchi method, has been developed to determine the optimum conditions leading to higher tensile strength. Experiments were conducted on varying rotational speed, transverse speed, and axial force using L9 orthogonal array of Taguchi method. The present study aims at optimizing process parameters to achieve high tensile strength.
Comparision Of Various Lossless Image Compression TechniquesIJERA Editor
Today images are considered as the major information tanks in the world. They can convey a lot more information to the receptor then a few pages of written information. Due to this very reason image processing has become a field of research today. The processing are basically are of two types; lossy and lossless. Since the information is power, so having it complete and discrete is of great importance today. Hence in such cases lossless techniques are the best options. This paper deals with the comparison of different lossless image compression techniques available today.
To mitigate Black-hole attack with CBDS in MANETIJERA Editor
Mobile ad-hoc network is self configured network that consist of mobile nodes which communicate with each other. Distributed self-organized nature of this network makes it venerable to various attacks likes DOS attack, Black hole attack, wormhole attack and jamming attack etc. Blackhole attack is one of the serious attack in network in which information loss occur which degrades the performance of network. In this work black hole attack is detected with the help of CBDS (cooperative Bait Detection Algorithm) and MD5 is used for the security purpose. This work is implemented in Network simulator and performance is checked on the bases of network parameters.
Fault Tree Model for Failure Path Prediction of Bolted Steel Tension Member i...IJERA Editor
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Optimization of Preventive Maintenance Practice in Maritime Academy Oron
1. Akpan, W. Aet al. Int. Journal of Engineering Research and Applications www.ijera.com
ISSN : 2248-9622, Vol. 5, Issue 5, ( Part -6) May 2015, pp.103-109
www.ijera.com 103 | P a g e
Optimization of Preventive Maintenance Practice in Maritime
Academy Oron
Akpan, W. Aa
, Ogunsola T. Mb
a
Mechanical Engineering Department, University of Uyo
b
Boat and Shipbuilding Department, Maritime Academy, Oron
Abstract
This research study investigates preventive maintenance management of diesel engine generators at the Nigerian
Maritime Academy, Oron. An optimization methodology taking cognisance of equipment age was applied on
failure data of diesel engine generators obtained from the institution’s maintenance data base to provide cost
effective maintenance management / replacement programme for critical components of diesel engine
generators. The analyzed results using Matlab provides a cost and reliability template which can be used to
perform diesel generator maintenance management programme in the academy.
Keywords: Reliability, optimization, maintenance, modelling, maritime academy.
I. Introduction
The present Nigerian maritime academy Oron in Akwa Ibom State Nigeria started as a Nautical college of
Nigeria in 1979 with a mandate to train shipboard officers, ratings and shore-based management personnel and
in 1988 the college was upgraded to the present status and the mandate was expanded to training of all levels
and categories of personnel for all facets of the Nigerian maritime industry (Wikipedia, 2014).
The epileptic power supply in Nigeria has prompted the academy to generate its electricity for the
administrative activities of the institution using the diesel engine generators.
The diesel engine has become the overwhelming choice for marine industries both on board and off board.
This can be attributed to its, high performance. It has high reliability and a better fuel economy than
gasoline engine and is more efficient at light and full loads. The diesel engine generator emits fewer harmful
exhaust pollutants and is inherently safer because diesel fuel is less volatile than gasoline. However, diesel
engines can be ineffective under certain conditions, thus affecting engine performance especially when poor
diesel fuel quality is used and also when poor servicing and maintenance method is applied.
Maintenance is all actions which have the objective of returning a system back to another state. Thus,
maintenance has the ability to bring back the system quickly to its normal functional state and reduces
equipment down time (Moubray, 1995) and Tsang et al. (1999).
Maintenance can be categorized into two: corrective maintenance and preventive maintenance (Paz, 1994).
According to Koboa-Aduma (1991) Maintenance provides freedom from breakdown during operations.
Maintenance of equipment is essential in order to:
(i) keep the equipment at their maximum operating efficiencies;
(ii) keep equipment in a satisfactory condition for safe operations; and
(iii) reduce to a minimum, maintenance cost consistent with efficiency and safety.
Maintenance can be perfect and imperfect Pharm and Wang (1996) and Nakagawa (1987).
The Nigerian Maritime Academy Oron has among others 500KVA, 600KV and 800KVA diesel engine
generators to generate power for the administrative needs of the academy The maintenance costs of diesel
engine generators in the academy is on the increase. This is mostly caused by lack of clear maintenance
methodology by the institution to maintain these generators. The objective of this research is to conduct a
maintenance methodology on 500KVA, 600KVA and 800KVA diesel engine generators own by the academy
and to suggest ways maintenance and replacement actions should be performed on the generators with the
objective of reducing the cost of maintenance at the required reliability of the diesel engine generators.
II. Methodology
The data were collected from both primary and secondary sources. The primary data were obtained from the
log book for a period of three years. This data include the time of failure of the diesel engine generator, the
components causing the failure and also when the failed components were repaired or replaced. The secondary
information was obtained from maintainers, supervisors, engineers and managers. This information include:
maintenance cost, failure cost and replacement cost of each part. Ten critical parts in the diesel engine were
RESEARCH ARTICLE OPEN ACCESS
2. Akpan, W. Aet al. Int. Journal of Engineering Research and Applications www.ijera.com
ISSN : 2248-9622, Vol. 5, Issue 5, ( Part -6) May 2015, pp.103-109
www.ijera.com 104 | P a g e
selected for the study. The data formed input into a maintenance and replacement model by Kamran (2008).The
information was used to predict future maintenance planning for the three diesel generators in the next 60
months with the objective of reducing maintenance cost and increasing the reliability of the diesel generators
used by the institution.
III. Optimization model
The model by Kamran (2008) provides a general framework that was applied on the study. In the total cost
minimization equation, the constraints for the solution of the equation are as follows:
(i) Constraints that address the initial age of each component at the beginning of planning horizon.
Thus;
Xἰj = 0; 𝑖 = 1… N 1
where 𝑖 = component, j = period& N=No of components
(ii) Effective age of the components based on preventive maintenance activities recursively.
)()1)(1( '
1,11,1,1,, jjjjijijiji iXmXrmX 2
𝑖 = 1… N and j = 2. . . T
J
T
XX jiji ,
'
, 𝑖 = 1, N and j = 1. . . T 3
jiji rm ,, ≤ 1; 𝑖 = 1. . . N and j = 1. . . T
Where: jiX , Effective age of component 𝑖 at the start of period j,
'
, jiX : Effective age of component 𝑖 at the end
of period j.
T = No. of periods, J = No. of intervals, jim , :
1
0
if component 𝑖 at period j is maintained, otherwise.
jir , :
1
0
if component 𝑖 at period j is replaced, otherwise, 𝛼𝑖: Improvement factor of component 𝑖
(iii) Condition/constraint preventing occurrence of simultaneous maintenance and replacement actions on the
components.
series
XXT
j
N
i RRe ijiijii
)()((
1
,
'
,
4
jim , , jir , = 0 or 1; 𝑖 = 1. . . N and j = 1. . . T 5
jiX ,
'
, jiX ≥ 0 ; 𝑖 = 1, N and j = 1. . . T 6
Where𝜆𝑖: Characteristic life (scale) parameter of component 𝑖
𝛽𝑖: Shape parameter of component, 𝑖, RRseries: Required reliability of the series system of components.
Consider the case where component i is maintained in period j. For simplicity, it is assumed that the
maintenance activity occurs at the end of the period. The maintenance action effectively reduces the age of
component i at the beginning of the next period. That is:
Xi,j+1 =
'
, jiiX for i = 1,…, N; j=1,…,T and (0 ≤ α ≤ 1) 7
The term α is an “improvement factor”, similar to that proposed by Malik (1979), Jayabalan (1992). This factor
allows for a variable effect of maintenance on the aging of a system. When α = 0, the effect of maintenance is to
return the system to a state of “good-as new”. When α = 1, maintenance has no good effect, and the system
remains in a state of “bad-as-old”.
The maintenance action at the end of period j results in an instantaneous drop in the ROCOF of component i,.
Thus at the end of period j, the ROCOF for component i is )( '
ji Xv . At the start of period j + 1 ROCOF drops
to )0(iv
If component i is replaced at the end of period j, the following applies:
01, jiX =0 fori = 1,…,N; j=1,…,T 8
3. Akpan, W. Aet al. Int. Journal of Engineering Research and Applications www.ijera.com
ISSN : 2248-9622, Vol. 5, Issue 5, ( Part -6) May 2015, pp.103-109
www.ijera.com 105 | P a g e
i.e., the system is returned to a state of “good-as-new”. The ROCOF of component i instantaneously drops from
)( '
, jii Xv to )( '
, jii Xv
If no action is performed in period j, there is no effect on the ROCOF of component i and thus :
'
, jiX = jiX , +
𝑇
𝐽
for i = 1,…, N; j=1,…,T 9
'
1, jiX = jiX , for i = 1,…, N; j=1,…,T 10
iv (Xi,j+1) = )( , jii Xv for i = 1,…, N; j=1,…,T 11
T = No. of periods, j = No. of intervals, ROCOF = Rate of Occurrence of Failure
For a new system, the cost associated with all component levels of maintenance and replacement actions in
period j, remains as a function of all the actions taken during that period.
The expected number of failures of component i in period j, i
dttvNE i
jiX
Xji ji
)(][ .
,
'
,
for i = 1,…, N; j= 1,…, T 12
Under the Non- homogenous piosson process assumption (NHPP) the expected number of component i failures
in period j is
)()(][ ,
'
,, jiijiiji XXNE i
for i = 1,…, N; j= 1,…, T 13
If the cost of each failure is iF , which in turn allows the computation of, F i j, the cost of failures attributable to
component i in period j is:
F i j = ][ , jii NEF for i = 1,…, N; j= 1,…, T 14
Hence regardless of any maintenance or replacement actions (which are assumed to occur at the end of the
period) in period j, there is still a cost associated with the possible failures that can occur during the period.
If maintenance is performed on component i in period j, a maintenance cost constant Mἰ is incurred at the
end of the period. Similarly If component i is replaced, in period j, the replacement cost is the initial purchase
price of the component i, be denoted by R i.
For a multi-component system, the cost structure is defined as stated above the problem can be reduced to a
simple problem of finding the optimal sequence of maintenance, replacement, or do-nothing for each
component, independent of all other components. That is, one could simply find the best sequence of actions for
component one regardless of the actions taken on component two and so on. This would result in N independent
optimization problems. Such a model seems unrealistic, as there should be some overall system cost penalty
when an action is taken on any component in the system. It would seem that there should be some logical
advantage to combine maintenance and replacement actions, e.g., while the system is shutdown to replace one
component, it may make sense to go ahead and perform maintenance/replacement of some other components,
even if it is not at its individual optimum point where maintenance or replacement would ordinarily be
performed. Under this scenario, the optimal time to perform maintenance/replacement actions on individual
components is dependent upon the decision made for other components. As such, a fixed cost of “downtime”, Z
, is charged in period j if any component (one or more) is maintained or replaced in that period. Consideration of
this fixed cost makes the problem much more interesting, and more difficult to solve, as the optimal sequence of
actions must be determined simultaneously for all components.
From the vantage point, at the start of period j = 0, it is right to determine the set of activities, i.e.,
maintenance, replacement, or do nothing, for each component in each period such that total cost is minimized.
In order to have X i j age of component i at the end of period j by using equation 2. First, define m i j, and r i j, as
binary variables of maintenance and replacement actions for component i in period j as:
jim ,
1
0
if component 𝑖 at period j is maintained, otherwise. 15
jir ,
1
0
if component 𝑖 at period j is replaced, otherwise. 16
The following recursive function of Xi j, X’ i j, m i j, r i j, α, with a constraint are constructed:
)()1)(1( 1,1,
'
1.1,1,, jijijijijiji XmXrmX 17
J
T
XX jiji '
,
'
, 18
4. Akpan, W. Aet al. Int. Journal of Engineering Research and Applications www.ijera.com
ISSN : 2248-9622, Vol. 5, Issue 5, ( Part -6) May 2015, pp.103-109
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jim , + jir , ≤1 19
In addition, the initial age for each component is equal to zero:
jiX , =0 for i =1,…,N 20
If component replacement occurs in the previous period then,
1, jir = 1, jim =0, 21
jiX , . If a component is maintained in the previous period then
1, jir = 1, jim =1 22
jiX , =
'
1, jiiX 23
and finally if nothing is done,
1, jir =o, 1. jim = 0 and jiX , =
'
1, jiX 24
which corresponds to our basic assumptions given in equation one. From the definitions of each type of cost, the
total cost function is:
))]1(1([)))()([( .,
1 1
,,,,,
'
,
1 1
min jiji
T
j
N
i
jijijijijiJIi
N
i
N
j
iimum rmZrRmMXXFCostTotal ii
Subject to: 25
0, jiX . i=1….N 26
)()1)(1( 1,1,
'
1.1,1,, jijijijijiji XmXrmX i=1…N, j=2…T 27
J
T
XX jiji '
,
'
, i=1….N, j=1….T 28
jim , + jir , ≤1 i=1….N, J=1….T 29
series
XXT
j
N
i RRe ijiijii
)()((
1
,
'
,
jim , , jir , = 0 or 1; 𝑖 = 1. . . N and j = 1. . . T 30
jiX ,
'
, jiX ≥ 0 𝑖 = 1, N and j = 1. . . T 31
This objective function computes the total minimum cost subject to the above stated constraints with input
parameters from tables 1, 2 and 3.
The generalized reduced gradient and the simulated annealing algorithms were used to solve the cost
minimization using Matlab software and the results presented in tables 4, 5 and 6. Tables 1, 2 and 3 were
generated based on data obtained from maintenance log book and information from maintenance engineers.
IV. Results and discussion
The characteristic life , shape factor , maintenance factor , failure cost, maintenance cost, and
replacement cost are presented in tables 1, 2 and 3 for 500KVA, 600KVA and 800KVA diesel generators
respectively for the selected components shown in tables 1.2 and 3.
Table 1 Parameters for 500KV a diesel generator
Mo
nth
Component λ(Days) β ∝
Failure
Cost (N)
Maintenanc
e Cost (N)
Replacement
Cost (N)
1. Injector Pump 950 0.0005 0.00025 128,000.00 68,000.00 91,000.00
2. Calibration of Valve 1080 0.0007 0.00025 340,000.00 32,000.00 180,000.00
3. Cutting of Ring 1090 0.0004 0.00025 210,000.00 80,000.00 170,000.00
4. Top Gasket Cylinder
Replacement
1170 0.0004 0.00025 260,000.00 80,000.00 183,000.00
5. Radiator 1050 0.0004 0.00025 96,000.00 16,000.00 36,000.00
6. Oil Pump 1005 0.0004 0.00025 80,000.00 16,000.00 80,000.00
5. Akpan, W. Aet al. Int. Journal of Engineering Research and Applications www.ijera.com
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7. Injector Nuzzle 900 0.0005 0.00025 270,000.00 80,000.00 270,000.00
8 Air Filter 1160 0.0004 0.00025 120,000.00 40,000.00 80,000.00
9 Alternator 250 0.0006 0.00025 154,000.00 46,000.00 85,000.00
10 Water Pump 1050 0.0005 0.00025 87,000.00 40,000.00 70,000.00
The characteristics life and shape factors were calculated from failure data while the failure costs,
maintenance costs and replacement costs data were obtained from maintenance engineers. The maintenance
factors were assumed based on the frequency of failure of components.
Table 2 Parameters for 600KV a diesel generator
Month
Component λ(Days) β ∝
Failure
Cost (N)
Maintenanc
e
Cost (N)
Replacement
Cost (N)
1. Injector Pump 1100 0.0007 0.00010 128,000.00 68,000.00 91,000.00
2. Calibration of Valve 800 0.0006 0.00010 340,000.00 32,000.00 180,000.00
3. Cutting of Ring 470 0.0003 0.00010 240,000.00 80,000.00 190,000.00
4. Top Gasket Cylinder
Replacement
1020 0.0005 0.00010 310,000.00 80,000.00 189,000.00
5. Radiator 1020 0.0004 0.00010 96,000.00 16,000.00 36,000.00
6. Oil Pump 800 0.0005 0.00050 80,000.00 16,000.00 80,000.00
7. Injector Nuzzle 900 0.0005 0.00050 270,000.00 80,000.00 270,000.00
8 Air Filter 1200 0.0006 0.00050 160,000.00 40,000.00 110,000.00
9 Alternator 990 0.0006 0.00050 210,000.00 76,000.00 115,000.00
10 Water Pump 780 0.0007 0.00050 87,000.00 40,000.00 70,000.00
The failure cost is higher than replacement cost which in the same vain higher than the maintenance cost. The
costs of components in 600KVA, 700KVA and 800KV generators are different in some cases or similar in
others.
Table 3 Parameters for 800KV a diesel generator engine
Month
Component λ(Days) Β ∝
Failure
Cost (N)
Maintenance
Cost (N)
Replacement
Cost (N)
1. Injector Pump 900 0.0005 0.00022 128,000.00 68,000.00 91,000.00
2. Calibration of Valve 1050 0.0004 0.00035 340,000.00 32,000.00 180,000.00
3. Cutting of Ring 1050 0.0005 0.00038 210,000.00 80,000.00 170,000.00
4. Top Gasket Cylinder
Replacement
980 0.0007 0.00034 33,600.00 6,720.00 28,800.00
5. Radiator 1010 0.0003 0.00032 310,000.00 80,000.00 189,000.00
6. Oil Pump 1015 0.0003 0.00028 96,000.00 16,000.00 36,000.00
7. Injector Nuzzle 1020 0.0003 0.00015 80,000.00 16,000.00 80,000.00
8 Air Filter 1030 0.0005 0.00012 270,000.00 80,000.00 170,000.00
9. Alternator 1010 0.0003 0.00025 270,000.00 80,000.00 170,000.00
10. Water Pump 1110 0.0006 0.00020 120,000.00 40,000.00 80,000.00
In tables 4, 5 and 6 the minimum required reliability is presented in the third column by the decision maker,
while a search algorithm of generalized reduced gradient and simulated annealing calculate the total optimized
cost function for each component and the optimum reliability in the sixth column using Matlab software. A gap
analysis shows the effectiveness of each algorithm. At 98% reliability and a total optimized cost of 7,082,250.51
naira, six number periods at ten months per period for the 60 months prediction has the highest cost. This is
expected because of the high expected reliability of 98% and long period of maintenance. However this option
is less preferable to 36 number of periods and about 1.7 months per period and a cost of 960,421,43 naira by
generalized gradient method at a reliability of 50% for the 500KVA diesel generator as shown in table 4.
6. Akpan, W. Aet al. Int. Journal of Engineering Research and Applications www.ijera.com
ISSN : 2248-9622, Vol. 5, Issue 5, ( Part -6) May 2015, pp.103-109
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Table 4 Required reliability and total cost optimized function for 500KV diesel generator
However for the 600KVA and 800KVA diesel engine generators, 48 periods , representing an interval of
1.25 months, has the lowest cost of 950,421,43 naira at 50% reliability. This formulation presents different
options for the decision maker and is effective in making maintenance management decisions for the assets.
Table 5 Required reliability and total cost optimized function for 600KVA diesel generator
No. of
components
Number of
periods
Required
Reliability
Algorithm
Total cost optimized
function value (OFV)
Reliability
(%)
OFV Gap
10 6 97 Generalized reduced
Gradient (GRG)
2,965,264.07 70.00 -
Simulated
Annealing (SA)
3,154,952.01 69.64 6.40%
12 90 GRG 5,693,688.96 90.00 -
SA 6,049,626.347 90.02 6.25%
18 80 GRG 2,675,884.570 80.00 -
SA 2,839,417,283 79.80 6.11%
24 70 GRG 1,143.506.918 70.00 -
SA 1,216,657.052 69.64 6.40%
30 60 GRG 3.576,008.178 60.00 -
SA 3,812,394.917 59.93 6.61%
36 50 GRG 2,264,196.091 50.00 -
SA 2,416,235.994 49.00 6.71%
42 97 GRG 3,732,178.10 60.00 -
SA 3,913,284.73 60.54 4.85%
48 90 GRG 960,421,43 50.00 -
SA 1,006,157.79 49.47 4.76%
54 80 GRG 1,467,308.49 97.00 -
SA 1,549,307.76 97.02 5.59%
60 70 GRG 2,127,321.16 90.00 -
SA 2,260,309.31 90.02 6.25%
No. of
components
Number of
periods
Required
Reliability
Algorithm
Total cost optimized
function value (OFV)
Reliability
(%)
OFV Gap
10
6 98
Generalized reduced
Gradient (GRG)
7,082,250.51 98.00 -
Simulated Annealing
(SA)
7,499,248.68 97.95 5.89%
12 90 GRG 1,840,017.981 97.00 -
SA 1,942,845.804 97.02 5.59%
18 80 GRG 4,767,597.09 90.00 -
SA 5,014,618.05 90.01 5.17%
24 70 GRG 2,813,854.26 70.00 -
SA 2,950,837.53 69.50 4.87%
30 60 GRG 3,732,178.10 60.00 -
SA 3,913,284.73 60.54 4.85%
36 50 GRG 960,421,43 50.00 -
SA 1,006,157.79 49.47 4.76%
42 97 GRG 1,467,308.49 97.00 -
SA 1,549,307.76 97.02 5.59%
48 90 GRG 2,127,321.16 90.00 -
SA 2,260,309.31 90.02 6.25%
54 80 GRG 1,156,146.96 80.00 -
SA 1,226,803.17 79.80 6.11%
60 70 GRG 2,965,264.07 70.00 -
SA 3,154,952.01 69.64 6.40%
7. Akpan, W. Aet al. Int. Journal of Engineering Research and Applications www.ijera.com
ISSN : 2248-9622, Vol. 5, Issue 5, ( Part -6) May 2015, pp.103-109
www.ijera.com 109 | P a g e
Table 6 Required reliability and total cost optimized function for 800KVA diesel generator
No. of
components
Number of
periods
Required
Reliability
Algorithm
Total cost optimized
function value (OFV)
Reliability
(%)
OFV Gap
10 6 80 Generalized reduced
Gradient (GRG)
1,885,488.0 80.00 -
Simulated
Annealing (SA)
2,000,716.8 79.80 6.11%
12 70 GRG 1,968,848.0 70.00 -
SA 2,094,795.2 69.64 6.40%
18 60 GRG 2,061,760.0 60.00 -
SA 2,198,049.6 59.93 6.61%
24 97 GRG 1,182,446.4 97.00 -
SA 1,248,526.4 97.02 5.59%
30 90 GRG 1,586,476.8 90.00 -
SA 1,685,654.4 90.02 6.25%
36 50 GRG 2,207,536.0 50.00 -
SA 2,355,771.2 49.00 6.71%
42 97 GRG 3,732,178.10 60.00 -
SA 3,913,284.73 60.54 4.85%
48 90 GRG 960,421,43 50.00 -
SA 1,006,157.79 49.47 4.76%
54 80 GRG 4,767,597.09 90.00 -
SA 5,014,618.05 90.01 5.17%
60 70 GRG 2,786,005.66 80.00 -
SA 2,918,223.78 80.00 4.75%
V. Conclusions
The results presented from the research show that Kamran (2008) formulation can be used in maintenance
decision making for diesel engine generators. The research also shows that shorter maintenance interval is much
preferable for multiple component equipment at an optimum reliability of 50%. From the results, the generalized
gradient method algorithm provides a lower total optimized cost compared to simulated annealing method and
therefore recommended in solving such problems. This methodology is therefore recommended to the Maritime
Academy Oron for effective maintenance management programme for the diesel engine generators.
References
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Ph.D thesis, University of Louisville, Kentucky, USA.
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[10] Wikipedia (2014) Maritime Academy of Nigeria : Available [Online] http//en.wikipedia.org