Correlation between Averages Times of Random Walks On an Irregularly Shaped Objects and the Fractal Dimensions

This study is  strongly motivated by fractal dimensions concept and dearth of relevant literatures aimed at correlating the average time of Random Walks on irregularly shaped planar objects and their corresponding fractal dimensions. Twenty selected countries maps from around the World were investigated to determine their random walk parameters and their fractal dimensions. The images (maps) were scanned, burned and saved as black and white Jpeg files. A program – visual basic 6.0 was developed for fractal dimensions and random parameters estimation. The program calculated: for each image number of boxes around the boundary of an image for 20x20 grids, and the distance covered by 100 random walkers on an image for the same number of grids. Thereafter, the program displayed a log-log graph of boundary count versus grids and log-log average time versus distance. The corresponding slope of line of best fit represents respectively the fractal dimension and random walks parameters. Preliminary investigation focusing grid size suggests 20x20 grids as non-compromising in terms of results reliability and computation expenses. The random parameters estimated based on 20x20 ranges from 1.976 to 2.995 while the estimated fractal dimensions range from 1.116 to1.212. The correlation of fractal dimensions and random walks parameter had regression value R2 = 0.014. The estimated fractal dimension showed that maps (images) boundaries are statistically fractal. However, there is no correlation between their fractal dimensions and the corresponding random parameters. KEY WORDS: Random walk, Shapes, Grids, Parameters, Dimension

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

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

Numerical Simulation and Modeling of UNSA91060 for Heat Transfer in Four-Stroke ICE Cylinder Head

This work concerns heat transfer principles in four strokes ICE from modeling and simulation standpoint.Heat transfer is one of a number of indispensable tools in studying of ICEs, due to its influence on decisive parameters of operation like temperature and pressure inside the cylinder. It is safe to say that modeling of the engine heat transfer is among the most complex problems for engineers. Application of numerical methods to predict the heat transfer in a cylinder of reciprocating ICEs is a process of high importance, which was recognized from the earliest stages of their development. This is done to examine performance optimization and design improvement in order to meet nowadays demands exhibited on the engines. This present study focuses on a 3-D transient state temperature distribution analysis on a gasoline engine model via formulated of models, simulating using FEM in-built in the COMSOL Multiphysics software 4.3a to determine the temperature distribution and gradient of the engine cylinder head model. The number of degrees of freedom solved for were 32685 in 383 s (12 minutes, 20 seconds) in the mesh optimization. From the result obtained it was discovered that the heat transfer in the combustion chamber of the ICE varies with time. Thus, it took the engine 10 minutes to complete a cycle vis-a-vis transfer of heat after combustion and that the heat transfer starts after 30 seconds of combustion. In addition, the temperature of the cylinder dropped from 1273.2 K to 301 K over a period of 10 minute.Self-sponsore

Development of an Ambient Control Method for Tomatoes Preservation

The quality of tomatoes depends on post harvest handling, transportation and storage techniques. Tomatoes cannot be kept for a long period of time due to their perishable and seasonal nature, it is therefore necessary to preserve it in seasons when available in other to ensure constant supply throughout the year with their nutritional value still retained. However, a 0.22 cubic metre capacity storage facility that operates on the principle of evaporative cooling, which is to increase the shelf life of stored tomatoes was designed, fabricated and tested. Data were observed twice daily and Results of the transient performance tests revealed that 117W is the cooling capacity of the produce (tomatoes) at 29.50C. Also, it was observed that the dry bulb (21-300C) and wet bulb (14.5-240C) temperatures are inversely proportional to the relative humidity (39-56%) of the cooler, which in turn show inverse relationship between the saturation efficiency (0-74.42%) and by-pass factor (0.26-1.00). An evaporative cooling system should be utilized to preserve tomatoes and other forms of vegetables at their minimal storage temperature in fourteen days relative to ambient storage. Thus, it has the prospect of being used for short term preservation of tomatoes soon after harvest and it will be very useful in helping the farmers most especially in a developing economy like Nigeria. Key words: Evaporative cooling systems, tomatoes, preservation, temperature, relative humidity, cooling efficiency, cooling capacity.

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

Parametric and Quantitative Analysis on the Development of Shell and Tube Heat Exchanger

This work is aimed at developing a prototype shell and tube heat exchanger using locally available technology and materials via design based on optimal combination of parameters using LMTD technique, fabrication, as well as, performance evaluation of the facility.The importance of mini shell and tube heat exchangers (STHEs) in industrial and other engineering applications cannot be underestimated. Hence, based on the problems associated with the design of STHEs, a mini STHE was developed for transfer of heat between two fluids without mixing on the laboratory scale using locally available materials and technology based on an optimized LMTD technique. The performance of the heat exchanger was assessed and evaluated to determine the optimum combination of design parameters. Copper was utilized for the tube side fluid due to its higher thermal conductivity and anti-microbial property, while galvanized steel was used for the shell side fluid due to its cost and corrosion resistance. Parametric studies were carried out on STHE design parameters to obtain an optimal design for efficiency and effectiveness after relevant design considerations. Experimental results were validated with quantitative models, and it was discovered that both Dell-Belaware and Engineering Science Data Unit (ESDU) approaches produced the optimal results required for the selection of shell side and tube fluid film coefficients, respectively over other correlations. In conclusion, the values of parameters of interest were also presented after rigorous mathematical calculations at optimal level and probable recommendations were later made.Self-sponsore

Development of an Ambient Control Method for Tomatoes Preservation

Thus, this work is aim at developing an ambient control method for tomato (Lycopersicum esculentum) preservationThe quality of tomatoes depends on post harvest handling, transportation and storage techniques. Tomatoes cannot be kept for a long period of time due to their perishable and seasonal nature, it is therefore necessary to preserve it in seasons when available in other to ensure constant supply throughout the year with their nutritional value still retained. However, a 0.22 cubic metre capacity storage facility that operates on the principle of evaporative cooling, which is to increase the shelf life of stored tomatoes was designed, fabricated and tested. Data were observed twice daily and Results of the transient performance tests revealed that 117W is the cooling capacity of the produce (tomatoes) at 29.50C. Also, it was observed that the dry bulb (21-300C) and wet bulb (14.5-240C) temperatures are inversely proportional to the relative humidity (39-56%) of the cooler, which in turn show inverse relationship between the saturation efficiency (0-74.42%) and by-pass factor (0.26-1.00). An evaporative cooling system should be utilized to preserve tomatoes and other forms of vegetables at their minimal storage temperature in fourteen days relative to ambient storage. Thus, it has the prospect of being used for short term preservation of tomatoes soon after harvest and it will be very useful in helping the farmers most especially in a developing economy like Nigeria.Self-sponsore

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