Cohen-Coon PID Tuning Method: A Better Option to Ziegler Nichols-Pid Tuning Method

Controller loop tuning is the process of manipulating the parameters (gains) in a proportional-integral-derivative (PID) controller in order to give satisfactory response to the process system. A satisfactory response is one that exhibits the desired speed of response, yet meets the required accuracy and stability criteria. Control processes are generally tuned under operating conditions, as opposed to start-up conditions, so that the process variable is stable at an operating point. In the industry, the PID human tuning method normally applies to machinery tuning is the Ziegler Nichols (ZN) tuning method, known as the ZN-PID tuning method. However, this PID controller tuning method is ineffective in the control of nonlinear and complex system with varied parameters, large inertia and large delay, as it tends to give a very higher overshoot, higher rise time and higher settling time in the system operation. These disturbances, due to the nonlinearity of the system under control cause the controller to produce poor responses at the output, leading to poor system performance. The limitations in this ZN-PID tuning method could be overcome by using Cohen-Coon-PID (CC-PID) tuning method to drive the system plant. In a nutshell, this research work takes a look at the CC-PID tuning method as betterment to the current ZN-PID tuning method being mostly used in the industrial machinery control. This research work finds application in any PID controlled plant.

Numerical solution of Black–Scholes Partial Differential Equation using Direct solution of second-order Ordinary Differential Equation with two-step hybrid Block Method of Order seven

This paper proposes a new numerical solution of Black-Scholes Partial Differential Equation using Direct solution of second-order Ordinary Differential Equation ODE with two-step hybrid Block Method of Order seven directly. The method is developed using interpolation and collocation techniques. The use of the power series approximate solution as an interpolation polynomial and its second derivative as a collocation equation is considered in deriving the method. Properties of the method such as zero stability, order, consistency, convergence and region of absolute stability are investigated The new method is then applied to solve Black–Scholes equation after converting it to the system of second-order ordinary differential equations and the accuracy is better when compared with the existing methods in terms of error

Numerical Simulation of Temperature Distribution in A Tri-Cycle Engine Piston

This present study will focus on temperature distribution and heat transfer rate which are of much importance especially in spark ignition (SI) engines. This was achieved by formulating a model for analyzing the temperature distribution in an internal combustion engines piston as well as simulates the obtained results using COMSOL- Multiphysics.Pistons as one of the most complex components among all automotives and other industry field components are designed to withstand damage caused due to extreme heat and pressure of combustion process. Many of experimental studies regarding the internal combustion engines process have been carried out, but few had only focused on the numerical studies like stress distribution, thermal and heat transfer analysis. This present study focuses on a 3-D transient state temperature distribution analysis on a gasoline piston model of a tri-cycle. Mathematical model was formulated, solved and simulated using a Finite Element Method (FEM) in-built in the COMSOL Multiphysics software 4.3a to determine the temperature distribution and gradient of the piston model ranging from 523K – 673K. The parameters used for the simulation were liquid (Gasoline), Gases (Air) and Aluminium alloy UNSA96061 (Piston). The Completed mesh tetrahedral consists of 86225 elements and the number of degrees of freedom solved for were 18553 in 367 s (6 minutes, 7 seconds) in the mesh optimization. It was discovered from the results obtained that the temperature in the combustion chamber of the tricycle engine varies with respect to time, along the piston.The transient analysis from the time dependent solver revealed that the temperature of the piston at the TDC (Top Dead Centre) in the first power stroke is higher compared to the subsequent power strokes, which is an indication that more heat was transfer at subsequent power strokes. Probable recommendations were later made.Self-sponsore

Lemon Juice Enhances Antioxidant Nutritional Quality of Tomato (Solanum lycopersicon)

The tomato plant is economically important and nutritionally beneficial to man. It is perishable in nature and preserved traditionally using lemon juice. The effects of this practice on antioxidant nutrients of this global vegetable food crop were investigated in this study. Tomatoes were preserved in four jars labelled 1 to 4. Jar 1 contained peeled, ground tomatoes (PG) and peeled non-ground tomatoes (PNG) without lemon juice. Jar 2 contained peeled, ground tomatoes and peeled non-ground with lemon juice (PG+LJ and PNG+LJ). Jar 3 contained unpeeled, ground tomatoes (UPG) and unpeeled non-ground (UPNG) samples while jar 4 contained unpeeled, ground and unpeeled non-ground samples with lemon juice (UPG+LJ and UPNG +LJ). The samples were analyzed for their antioxidant contents. Results revealed that concentration of ascorbic acid in tomato samples preserved with lemon juice varied from 14.70 – 20.30mg/100g FW. The values were significantly different (p<0.05) from the controls (PG, UPG, UPNG and PNG). The total phenolics content of lemon juice preserved tomatoes were also significantly different (p<0.05) from the control samples with UPNG+LJ having the highest phenolics content of 12.90mg/100g. The value of flavonoids ranged from 1.51 (PNG) to 2.95mg/100g (UPG+LJ) while ?-Carotene was from 1.78mg/100g (PNG+LJ) to 4.68mg/100g (PG+LJ). The unpeeled samples generally had higher antioxidant nutrients in comparison with the peeled samples. This study is relevant to the tomato canning industry and suggests that the use of lemon juice as tomato preservative agent should be encouraged. Keywords: Preservation; lemon juice; antioxidant nutrients, peeling; tomat

Morbidity and mortality due to induced abortions: A 5-year review of cases in a Nigerian Teaching Hospital

Context: - There is evidence that doctors now perform a high proportion of induced abortions in Nigeria. There is therefore a need to assess the current status of morbidity from induced abortionAim: To determine the socio-demographic characteristics of patients with complications of induced abortions, type of complications and outcome of care.Methods: all cases of complications of induced abortions admitted at the Wesley Guild Hospital, Ilesha Nigeria between January 2004 and December 2008 were the subjects of this study. The case notes of the patients werereviewed to obtain information on the socio demographic characteristics of the patients, contraceptive usage, type of complications, and the outcome of care.Results: There were 1,048 gynaecological admissions during the study period with 84(8.0%) admitted for complications of induced abortions. The mean age of the patients was 23.0 years, 56.8% were single nulliparouswomen and 47.1% were students. The gestational age at abortion ranged between 4 and 16 weeks with a mean of 9.9 weeks ( SD=3.6). The abortion was carried out in private health institutions in 81.1% of cases. Retained product of conception(85.4 %) ,sepsis (55.4%) and haemorrhage (35.1%) were the most common complications. There were 3 maternal deaths, given a case fatality rate of 4.1%, and 13.Conclusion: The pattern of complication of induced abortion has changed with a reduction in the proportion of patients with sepsis and the case fatality.Key Words: Induced Abortions; Socio-demographic characteristics, complications, morbidity; mortalit

Comparative analysis of exhaust gases obtained in S.I and C.I of an internal combustion engine

This paper is aimed at analyzing, determining and comparing the composition of exhaust gases of automobile ICE through experimental determination of the exhaust gas values at different loads and speeds of both engines; and determination of the effect of engine speeds and loads on exhaust emissions of both engines.ICE which could be spark ignition (S.I) or compression ignition (C.I) engine is one of the building blocks of modern civilization. In light of this, an effective engine should be able to contribute immensely to a safe environment. Numerous factors like fuel economy, power and torque, reliability, pollution, safety and cost are necessary in determining and comparing the effectiveness of the engines. This paper identifies, examines and compares the rate of incombustible particles present in the engines (S.I and C.I) at varying loading and speed conditions via exhaust gas detector. Post-hoc analysis was carried out using SPSS. It was discovered that CO and HC are the most dangerous incombustible particles present in engines and also the incombustible rate is more pronounced in C.I than S.I engine, which confirmed that S.I. engine is far better in terms of pollution reduction. Probable recommendations were later made.Self-sponsore

Application of Dynamic Programming Model to Production Planning, in an Animal Feedmills.

The problem of this study is that of determining the quantity of products to produce and inventory level to carry from one period to the other, with the objective of minimizing the total costs of production and the annual inventory, while at the same time meeting the customer’s demand. A mathematical model was formulated for a multi-product problem using Dynamic Programming approach. The model was solved using the solution procedure proposed by Wagner and Whitin. The results show that the minimum total cost will be achieved with production in periods 1, 2, and 4. While demand for period 3 are satisfied with inventory from period 2. The total cost of this plan is N225, 704, 210.00, which is N6, 155, 765.00 less than the existing plan. Keywords: Inventory, Model, Periods, Plan, Cost

Comparative Analysis of Gases Obtained From A Bio-Digester Using Different Waste Media

This work is aimed at comparing and analyzing the composition of gases obtained from a biogas plant using different media. This is achieved through construction of an improvised plant for gas collection, measuring and analyzing the quality of gases obtained in the plant and deducing the best waste medium based on the result obtained.The development of a technological devices and equipment for biogas production from different energy plants and organic wastes has made biogas a renewable source of energy generation. The interest in the use of the biogas as a renewable source of energy is increasing and also the scope of substrates for the anaerobic digestion process is on the increase. With the mini digester it is possible to observe the amount of biogas (methane gas) production and thus the most suitable plant, giving the maximum methane yield, can be determined. The mini digester made of galvanized steel was built, some measurements with energy plants were performed and then parameters such as biogas composition from animal wastes and crop residues were measured (in the laboratory) and compared. The highest biogas and methane yield was recorded in the animal waste. Probable recommendations were later made.Self-sponsore