Mechanical Design

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Biodiesel Production Optimization and Quality Assessment Using Jatropha Curcas Oil And Ethanol Alcohol
(Addis Ababa University, 2001) Demissie, Biniyam; Alemu, Demiss (PhD)
Concern over high transportation fuel costs, trade deficits, depleting resources, energy security, and mounting evidence of global climate change has led to re-investigation of fossil fuel alternatives. For this reason Ethiopian Ministry of Water and Energy has started promoting bio-energy as a means to transform the nation’s abundant renewable biomass resources into cost competitive, high power biofuels and products. Biodiesel offers one renewable fuel option that can be produced from non edible vegetable oil sources. Fortunately Ethiopia has many opportunities for biodiesel production. The country´s favorable climatic condition for the cultivation of non edible vegetable oil bearing plants and the abundance of ethanol alcohol produced from the byproduct of local sugar factories gave the country a great advantage in producing biodiesel and get a little relief from petroleum related problems. However, the effort made to introduce the technology and take the most out of it is so low to force policy makers and encourage local and foreign businessmen towards the production of biodiesel using local resources. Therefore this research tries to fill this gap. The main purpose of this research is therefore to develop a biodiesel production technique from Jatropha oil (Jatropha curcas Linnaeus) and a locally produced ethanol alcohol. Special attention was paid to the optimization of base-catalyzed transesterification for converting fatty acid ethyl ester (FAEE). The crude Jatropha oil used in the transesterification contained 5.01 mg KOH/g of acid and after neutralization it was possible to bring down the acid value to 1.35 mg KOH/g. Inorder to determine the optimum condition for tranestefication of Jatopha oil using ethanol and caustic soda as input, 16 experiments varyings ethanol-to-oil molar ratio (6:-9:1) and reaction temperature (55, 65, 70, and 78 oC). Reaction time, mixing intensity, and catalyst concentration was fixed to 3 hrs, 600 rpm, and 1.5 % by weight of the oil respectively. The optimum conditions found for transesterification were an ethanol-to-oil molar ratio of 9:1 and a reaction temperature of 70 0C. At the optimum condition obtained a FAEE conversion of 80 % v/v was achieved. The resulting Jatropha biodiesel has, a density of 0.86 g/ml, viscosity of 4.13 mm2/s, acid value of 0.71 mg KOH/g, and flash point of 173 0C satisfing ASTM D6751-02 and EN 14214 biodiesel standards. The production proces developed in this work will be used in production of a small scale plant withh capcity of 300 liter per day.
A Decision Support System on Equipment Replacement
(Addis Ababa University, 2002-06) Tecleab, Sium; Roy, R.N. (PhD)
Project Management Approach to The Establishment of Computer Assembly Plant in Ethiopia
(Addis Ababa University, 2002-06) Arefaine, Fessehatsion; Roy, R.N. (PhD)
The creation of the computer and the advancement in communication systems has led to the emergence of a new era called the information age. In the new era information is rapidly becoming the world's most valuable resources. The central part of the information technology (IT) is nothing but the computer. Due to its paramount importance the personal computer (PC) has become a part of day-to-day existence of people all over the world. As a result, the computer industry today is a trillion-dollar market. In order to narrow down the gap between the developed and developing nations, countries like Ethiopia should work hard to improve the level of their information and communication technology (ICT). These days it is realized that ICT is a proven tool that one must be equipped with in the fight against poverty and in the effort to secure sustainable economic development. ICT may be composed of four elements: computer hardware, software, communication equipment and know-how. The availability of PCs at cheaper prices and preferred designs would obviously enhance the development of ICT. It is seen that the demand for PCs in Ethiopia is increasing from time to time. But, the supply so far is from imports, with an expenditure of considerable sum of hard currency. In this regard, this thesis research attempts to analyze the feasibility of building a PC assembly plant in Ethiopia applying modern project management techniques. The research applies the method of trend analysis as well as market-buildup methods to estimate the xii present and future demand of PCs in Ethiopia. Make or buy decision analysis is carried out to indicate which components to make in-house and which ones to import form outside sources. The technology, organization and implementation plans are studied at the required depth. Finally, the financial viability of the project is analyzed with the help of appropriate software.
Productivity Improvement in Ethiopian Leather Industry Through Efficient Maintenance Managenet
(Addis Ababa University, 2004-06) Teklemariam, Misikir; Teklemariam, Misikir; Kitaw, Daniel (PhD)); Kitaw, Daniel (PhD))
Increasing global competition has made many business leaders and policy makers turn their attention to such critical issues as productivity and quality. Productivity improvement should be a concern of every industry regardless of the type of production, economic or political system. The definition of productivity, the ratio of output value to input value, remains the same for every sector. Productivity can either be improved through increasing the output value by increasing the quality or quantity of products, or through decreasing the input value by utilizing the resources effectively & efficiently. Efficient maintenance management is one way of improving the productivity through capital resources of the company. The paper examines how proper maintenance management improves the productivity of leather industries. Leather industry, as it is one of the potential economic sectors, it should be given proper attention for sustainable development of the country. Thus, the purpose of this paper is to propose improvement areas in maintenance activities of Ethiopian leather industries to improve their productivity by analyzing the problems associated with it.
Developing Project Performance Evaluation Model to Minimize Project Delay Based on Some Ongoing Industrial Projects
(Addis Ababa University, 2004-06) Geremew, Sisay; Roy., R.N. (PhD)
Delays and cost overruns are the rule rather than the exception in most industrial projects, and project management suffers from numerous problems of costing and scheduling. Cost overruns of 50 to 100% are common. Projects are often delayed to the point where the market conditions for which they were designed have changed. Many projects suffer from the "90% syndrome" in which a project is thought to be 90% complete for half the total time required. There is consensus among researchers and industry experts that one of the principal barriers to promote improvement in industrial projects is the lack of appropriate performance measurement. For continuous improvement to occur it is necessary to have performance measures which check and monitor performance, to verify changes and the effect of improvement actions, to understand the variability of the processes, and in general, it is a necessary to have objective information available in order to make effective decisions. The main body of this thesis is divided in to three major parts. The first part is a general literature review about the fundamentals and the process of project management, in which case the historical background of project management and the different functions of management (planning, organizing, monitoring and control) from the project stand point are revised. The second part of the thesis is all about data collection, analysis and presentation. In this case the different techniques of data collection are used to collect data and information some facts about Ethiopia on xi project performance evaluation criteria and the data is analyzed from different perspectives for presentation. In the last part of the thesis which is about the developing a general project performance evaluation model, three general project management models are discussed. Based on these general project management models and the data and information obtained from different parts of the country, a model is developed for performance evaluation. Finally a set of recommended model implementation steps and a general conclusion about the overall project performance evaluation is given.
Development of Production Planning and Control (Ppc) System of Job Order Companies in Ethiopia A Case Study on Akaki Spare Parts and Hand Tools Share Company (Aspsc)
(Addis Ababa University, 2004-06) Bawoke, Mezgebu; Kitaw, Daniel (PhD))
Planning system of any profit oriented company determines its survival. Whether a company is service giving or production type, the first thing expected from it is setting its objective properly. The process of setting objectives and their courses of action is planning. Manufacturing companies plan their production and formulate mechanisms of production controlling to be profitable and survive in the market. Production planning and control (PPC) is the process of deciding what to produce in advance, setting exact route of each item, fixing the starting and finishing date for each item, and following up the progress of products according to the order. PPC of job order companies is more complicated than that of non-job order companies. In this thesis work, PPC systems of some selected Ethiopian job order companies are analyzed. The PPC system of Akaki Spare Parts and Hand Tools Share Company, it problems and possible solution to the problems have been discussed in detail. Finally flowchart type of model which helps minimize the PPC related problems of ASPSC is developed. The model is developed after performing the following activities. 1. Visiting ASPSC and collecting all necessary data from it. 2. Visiting job order companies found in and outside Addis Ababa. 3. Visiting major customers of ASPSC. Data which are obtained from job order companies are used to compare the PPC system of ASPSC with other job order companies. Data which are collected from major customers are used as feedbacks to identify shortcomings of the PPC system of the company. Key words: PPC, Job Order Company, Forecasting, Aggregate Production Planning, Material Requirement Planning.
Computer Modeling and Simulation of Coal fired Cogeneration Power Plant
(Addis Ababa University, 2004-07) Tamirat, Yohannes; Alemu, Demiss (PhD)
This thesis describes a power plant simulator which has been developed using MATLAB code. The basis of the power plant modeled here is the design data of Coal-Phosphate Fertilizer Complex Project (COFCOP), and the type of boiler and turbine are taken as selected by the project. Therefore, the boiler modeled here is a circulating fluidized bed coal combustor type, and the turbine is an extraction condensing type at heat to power ratio. Conservation equations and characteristic curves are used to model each component of the power plant. From these mathematical model equations, the component modules are developed using MATLAB code. Output parameters are obtained from input data to the component modules. Simulation of systems, subsystems and components are accomplished using the Newton-Raphson technique. The total system of the power plant is simulated by a program called powerplant_main. In this program there are four basic solvers. These are: the turbine solver, the boiler solver, the water flow solver and the steam flow solver. Each solver has its own residue generator function and Jacobean generator function. The Gaussian elimination function is called by any solver during simulation. The power plant in COFCOP is still in design stage, and it cannot be used for program verification in this paper. Hence, a hypothetical power plant data is taken and the output of the simulation closely approximates the real case.
Transint Analysis of Cooling Load of a Single Zone Building
(Addis Ababa University, 2004-10) Fantu, Korbaga; Alemu, Demiss (PhD)
Cooling load calculation is the major work performed in the air-conditioning system design. This should be performed as accurately as possible to reduce over design or under design of the system. Some of the factors that influence results of cooling load are heat gain through wall and glass, infiltration of atmospheric air, ventilation, appliances load, and occupancy. The objective of this thesis is to develop a user-friendly program that can easily calculate space-cooling load of a single zone system taking some of the basic inputs like latitude, longitude time zone, building materials and other metrological data of the location. This thesis uses finite difference method for computation of transient heat conduction through the wall and roof. Implicit finite difference method is chosen for its stability.. To make the developed program more friendly, number of commonly used construction materials with their thermal properties are inbuilt in the program. Infiltration effect in the total cooling load is also discussed in detail. Various experimental data and graphs are used for determining the infiltration rate. Heat gain through window is calculated by taking solar heat gain coefficients (SHGC) of the various combinations of glass used. Various types of glass and glass combination with their thermal properties are also inbuilt in the program. The components of heat gain are finally categorized under convective and radiant portion. The convective portions are taken as cooling load. The radiant portions are changed to viii cooling load by multiplying them with radiant time factors. Beside the project uses number of assumptions proposed by ASHRAE for its calculation of heat gain and cooling load. All the above-mentioned influencing factors of cooling load calculation are dealt in-depth in the thesis in chapter 3 4 5 and 6. The results found are verified with results found in other literatures. Finally cooling load of an actual building in Gode is computed using the developed program.
A Petri net Approach to Bottling Line Modeling and Performance Analysis: A Case Study on Meta Abo Brewery Share Company
(Addis Ababa University, 2004-10) Lakew, Mesfin; Alemu, Demiss (PhD)
Increasing global competition has made many business leaders and policy makers turn their attention to such critical issues as productivity and quality. Businesses seek new approaches to production processes and manufacturing techniques and explore new boundaries of technology. One of the frequently prescribed remedies for the problem of decreased productivity and declining quality is the automation of factories. To achieve strategic benefits of automation in line with improved quality, greater flexibility, and cost reduction, firms must carefully manage the implementation of their techniques. In the light of the above, because of capital intensive and complex nature of automated manufacturing system (AMS), the design and operation of these systems require modeling and analysis in order to select the optimal design alternative and operational policy. Besides, errors in the modeling process can substantially contribute to the development time and cost. Therefore, special attention should be paid to the correctness of the models that are used at all planning levels. Petri nets as a graphical and mathematical tool provide a uniform environment for modeling, formal analysis and design of manufacturing systems. This study therefore, focuses on both traditional analysis of manufacturing system after setting key performance factors and the application of Petri nets in modeling and analysis of an AMS. It also includes a comprehensive review of xvi Petri nets and manufacturing system in view of Petri nets application domain. ith the view to give more emphasis in the practical and realistic industrial application of Petri nets, particularly in modeling and analysis of AMS, a case study on an existing manufacturing firm was carried. In this regard, Meta Abo Brewery S. Co (MABSCo) is believed to serve as a model. Above all, the success of Petri nets and related technologies can be greatly achieved only when more industrial engineers and designers use them together with other techniques in system development and operation. The author, being an industrial engineer, develop the sample model attributed to the bottling line of MABSCo through a careful study of relevant literatures, systematic data collection, and after systematic survey of the plant, particularly the bottling line. Further research in the future that includes other classes of Petri nets is also proposed to make the study more complete.
Design of Energy Efficient Buildings for Hot Areas of Ethiopia With Respect to Air Conditioning
(Addis Ababa University, 2004-10) W/abzgi, Teklay; Alemu, Demiss (PhD)
This thesis is intended to identify the design improvements of buildings that can be made for the hot region of Ethiopia. A detail literature survey is done on design improvements and those that can be most suitable and economical are suggested. A case study of two different buildings in Gode (one of the hottest area in Ethiopia) was conducted using building energy simulation software to quantify the energy saving from some of the design improvement measures such as using insulation in roof or ceiling and in walls, window glazing and shadings, and orientation. The simulation result verifies that using 75mm insulation in roof or ceilings give a better saving and most economical when the building has small glazing area with respect to the wall size and lower internal cooling load. And when the building has large glazing area using either internal or external window shading is the best way to reduce the annual energy cost of the building and 50mm roof insulation is most economical. In addition to the above results the relation between insulation and different conditions of cooling load in a building is verified. This result shows that when internal load and solar load through window are dominating insulation can have a negative impact to cooling load.
Aspects of Lean and Agile Manufacturing Systems and Their Appropriatness in Ethiopia
(Addis Ababa University, 2004-10) Zehrudin, Idris; Roy, R.N. (PhD)
The thesis deals with the principles of Lean and Agile Manufacturing Systems and their appropriateness in Ethiopian context. Inflexible mass-production methods that produce voluminous of standardized products were inadequate for demands of increased variety. In pursuit of greater flexibility and elimination of manufacturing wastes, Lean Production System has been developed. More recently, demand for further responsiveness to the everchanging customer demand and turbulent business environment, led to a formulation of Agile Manufacturing concept with the intention of greater adaptability. Thus, it is necessary to study their vital principles and adopt the appropriate system to improve the competitive capability of industries. Using available literatures, Internet, industry survey and analyzing the gathered pertinent information, the thesis reviewed the main principles of lean production system. Taking authentic pilot cases, enhanced value stream map is generated and lean Manufacturing Cell for cutlery production is designed. The fundamental principles of agile manufacturing system and then, the comparison of the two systems are also discussed. Finally the suitability of these systems in Ethiopia context is analyzed. It is found that Lean Manufacturing is a collection of technical and operational systems focused on productivity improvements with limited resources (44). LPS focuses on minimizing manufacturing wastes, continuously improving methods, utilizing flexible production system to produce variety of defect-free goods. Agile manufacturing (AM), on iii the other hand, is a comprehensive manufacturing system focused on thriving in unpredictable business environment. AM focuses on enriching customers, reorganizing production system for greater flexibility, cooperation to enhance market responsiveness and increased use of Information technology. The comparison between these systems shows a difference in viewpoint and perhaps strategy with regard to change, but not in method or approach. Cases on the implementation of Lean techniques indicate that industries can enhance competitiveness by adapting Lean. The survey revealed that Industries are experiencing forces that lead to more responsiveness. More over, it is found that most industries believe that the Lean Production is more appealing in current Ethiopian Industries Situation.
Computer-Aided Dynamic Force Analysis of Four-Bar Planar Mechanisms
(Addis Ababa University, 2004-11) Metiku, Robel; Bazezew, Alem (PhD)
The four-bar linkage is the most basic chain of pin-connected links that allows relative motion between links. Although a simple mechanism, the four-bar linkage mechanism is very versatile and used in thousands of applications. The main themes of this thesis are the modeling, computer-aided dynamic force analysis and simulation of four-bar planar mechanisms composed of rigid bodies and massless force and torque producing elements. Motions of the rigid bodies are predicted by numerically integrating Differential-Algebraic Equations (DAEs) developed from principles of mechanics by using the Newton-Euler’s approach. The computer program used for solving the equations developed in the analysis problem and that integrates the differential equations is Matlab.
Implementation of Just-in-Time Production System In Automotiive Manufacturiing Company of Ethiiopiia and Addiis Ababa Bottle & Glass Factory
(Addis Ababa University, 2004-11) Garoma, Temesgen; ROY, R.N. (PhD)
Traditionally, a manufacturing business competes on price, variety, and after service. Now, these conditions are merely prerequisites. Few businesses exist today without offering this requirement, and the key competitive factor has become speed. Major businesses have been trying to adopt new business initiatives in order to stay alive in the new competitive market place, and there is no question that the elimination of waste is an essential ingredient for survival in today's manufacturing world. Companies must strive to create high quality, and low cost products that can get to the customers in the shortest time possible. Just-in-time production system is one of these initiatives that focus on cost reduction by eliminating non-value added activities. The tools and techniques of JIT have been widely used in both discrete and process industry starting with the introduction of the original Toyota production system. This thesis addresses the implementation of Just-in-Time production system with focus on AMCE and AABGF. The goal of this research is to investigate how JIT can be implemented in these companies. This thesis attempts to introduce JIT from its conception, and many collaborative JIT concepts, components, elements, and tools that are used for the elimination of wastes are addressed. To develop the implementation model first the status of the companies were investigated and then the problems are identified and x formulated. The JIT implementation guidelines developed by APICS and others have been seen to develop the line implementation model of JIT for the companies. It has been seen that only a hybrid (Push-Pull) JIT systems is applicable to both companies. In the implementation model developed, Value stream mapping was used as a tool. The companies can use it to identify various types of waste in the value stream of the company and try to take steps to eliminate them. Finally the conclusions and recommendations are provided for the thesis.
Analysis of Traffic Accident In Addis Ababa: Traffic Simulation
(Addis Ababa University, 2006-06) Samson, Fanueal; CHANDRA (PhD)
This paper discusses the growing problem of road traffic crashes, particularly in Addis Ababa with particular reference to the magnitude, risk factors, interventions and research priorities. The 2004 World Health Report shows that of the 1.2 million people killed in road crash worldwide, 85% are in developing countries. The traffic police reports human error, road environment and vehicle factors as the main causes of road crashes. However, little documentation is available on the broader underlying factors such as deficiencies in the breviaries changes, ineffective road safety legislation and enforcement, systems for data collection and management, and inadequate medical infrastructure for post-injury management. Although a variety of road safety interventions have been successfully applied, little attempt has been made to promote and implement them. Every year, around 300 people are killed on Addis Ababa's roads and 1500 are light and seriously injured [Federal Police Central Bureau]. The governments have launched several campaigns, such as “Think!” and Road Safety Campaign (RSC), to help people become aware of road safety issues and try to reduce road accident. This study tries to analyze the traffic accidents, and develop a computer-based traffic simulation for the route selection. This thesis has two main functions. Firstly, the aim is to provide users with an understanding of the major causes of traffic accidents and present using several Statistical tools. At the second function, it will apply an innovative, hybrid statistical model for route selection based on accident prediction to traffic police office data. The system, if developed to include the whole network in Addis Ababa, will support several target groups, viz. all road users, Traffic Police and the Emergency and Fire Service through to insurance companies, and local government. The ideal system will Analysis of road traffic accidents in Addis Ababa: Traffic simulation iii give people useful suggestions about how to improve road planning and traffic management. In this paper, a survey is done on current prediction models and visualization techniques. A prototype system is developed using these theories. The functions in the prototype system are limited. More data is required to actualize the system on real terms. The study consists of two major parts: the first part gives detail about the road traffic accident, and Ant Based Control Algorithm implemented for road traffic management. The second part, customization of research empirical equations and experiences to our local conditions and simulate/ forecast the future trend and also with the help of software developed, route selection at the pick hours is managed for the specific path in Addis Ababa. In conclusion, the paper highlights the background of the growing problem of road traffic injuries in the city and provides some basis for optimism in tackling it.
Model Development of Quality Management System for Ethiopian Textile Industries A Case Study at Bahirdar and Akaki Textile Share Companies
(Addis Ababa University, 2006-06) Matebu, Amare; Kitaw, Daniel (PhD))
Today competition is truly global. Higher product quality is required for a company to become more competitive both local and in international market, and quality is the ultimate weapon. Any company basically competes on its reputation - for quality, reliability, price and delivery. And most people now recognize that quality is the most important of these competitive weapons. With the increasing global pressure of quality requirements, the traditional concept of quality control must be expanded to the concept of quality management. Quality management relies on people and involves everyone. Quality management is both a philosophy and a set of guiding principles that represent the foundation of a continuously improving organization, all the processes within the organization, and the degree to which present and future needs of the customer are met. Currently, almost all textile industries in Ethiopia are suffering from quality related problems. These problems include: poor performance of products in the export market, low quality and insufficient raw material supply, incompetence in the world market, customer dissatisfaction, low productivity, and poor utilization of the resources. Because of these problems, most of the textile companies in the country are not profitable and most are in a huge loss. This research work mainly focused on how this loss and low market share in textile companies could be removed with the help of quality management system (QMS). The objective of the thesis is to identify the major components of QMS for textile industries and to propose the appropriate implementation model of quality management system. Based on the survey of four textile industries and two case studies (Bahirdar and Akaki textile share companies), nine major components have been identified for QMS-implementation in Ethiopian textile industries. QMS provides consistency and satisfaction in terms of methods, materials, equipment, and interacts with all activities of the companies, beginning with the identification of customer requirements and ending with their satisfaction, at every transaction interface. A strong organizational culture with determined management and controlled feedback mechanism would ensure the effective implementation of the quality management system in textile industries.
“Modeling and Simulation of Solar Evaporative Crystallization of Lake Brine” (The Case of Lake Abijata/Salla)
(Addis Ababa University, 2006-07) Kore, Silashi; Alemu, Demiss (PhD)
Abijata Lake water constitutes the raw material for the production of salt in solar salt works. The salts are: Industrial salts------Sodium carbonate (Na2CO3) Edible salt-----------Sodium chloride (NaCl) The concentration of the Lake water through solar evaporation results in the successive crystallization of less soluble salts (Na2CO3, NaHCO3) first, followed by NaCl. Salt work uses the empirical Baume (OBe) Scale, to measure the concentration of the brines. According to that scale the Lake water concentration is 4.22 OBe (specific gravity of 1.03).The crystallization of Trona (Na2CO3.NaHCO3.2H2O) begins at 26.13 OBe (specific gravity of 1.22) and sodium chloride (NaCl) crystallize at 39.16 OBe (specific gravity of 1.37) Solar crystallization Processes Producing salt from the lake water involves the selective recovery of pure Trona (Na2CO3.NaHCO3.2H2O) and sodium chloride (NaCl), free of other soluble or non-soluble salts and other substances. To this end, an appropriate quantity of Lake Water is concentrated through natural evaporation, which leads to the fractional crystallization of all salts contained: a process based on their varying solubility. The basic step in the processes of salt recovery from the Lake water was made with the division of the evaporation basins in to two: The first basin, usually called nurse pond (pre-concentration pond), was used for the production of saturated brine, which was feed in to second basin, usually called crystallizer. What basically elevates Salt works to ecosystem is the fact for Lake Water to be concentrated up to the point salt crystallization. 90% of its salt content has to be evaporate, thus requires a vast surface. For this reason ponds (pre-concentration ponds) take up 90% of the salt work area. Crystallizers take up approximately 10% of the salt work area. Crystallizes take up the remaining 10% of the area. These basins are especially designed ix and have their bottom leveled and concentrated, aiming to facilitate and optimize the collection of salt with machinery. The first pond of the salt work is feed with Lake Water (raw material) usually via pumping. As the lake water flows along the pond, its concentration raises continuously through natural evaporation. The evaporation (concentration) of brine is achieved by exposure to solar radiation and with the help of the prevailing microclimate in the area, especially the winds, rainfall, air temperature and humidity and duration of sunshine. So an increasing salinity (concentration) gradient is created throughout the ponds of the salt works with a simultaneous and continuous reduction of the volume of Lake Water, which initially entered the system of ponds. This is the physicochemical process of salt production.
Computerized Activity Based Costing System for process industries, A Case Study On Zemilli Paint Factory
(Addis Ababa University, 2006-11) Gizaw, Mesfin; Alemu, Demiss (PhD)
There is increasing evidence that external and internal pressures are being placed upon companies to acknowledge, characterize and analyses environmental issues, impacts and costs. It has been becoming crucial that companies will increasingly be faced with responsibilities extending outside the factory gate to point of sale and beyond. Companies will need to adopt a life cycle perspective into the decision-making framework, to support managements' decisions regarding the environmental impacts and costs of activities and products. The manufacturing and process sector has suffered from poor management systems for a long time. In process industries, the need for better cost management systems arises from efficiency problems and lack of resources. With activity-based costing, the processes and the costs of activities become more transparent than earlier. ABC has highlighted that true understanding of what it costs to provide products/services is at the same time a tool for better management. It helps to better understand and serve as guides in any business process improvement initiatives, and to subject resources to its efficient usage. In a nutshell, it helps to make more effective business process improvement at more transparent cost. This study is an illustration to point out required changes that could be made during the activity-based costing process in Zemilli paint factory. It shows the benefits and advantages that have come true because of the ABC-process and discuss the problems connected to this process. The ABC-process consists of two phases. The phases and their outcomes are described in chapter four preceded by the basic principle of ABC in chapter three of this study. The first chapter of the thesis dedicated to introduction, background, the importance, objective and the general outline of the paper. The second chapter of the thesis gives the existing condition of process industries in Ethiopia considering specific attention to Zemilli paint factory. While the third chapter of the thesis is fully dedicated to literature survey and Computerized Activity Based Costing System for process industries, A Case Study On Zemilli Paint Factory. ______________________________________________________________________________________ ___________________________________________________________________________ Addis Ababa University, School of Graduate Studies, Department of Mechanical Engineering ix followed by chapter four which gives emphasis to problem formulation and the Activity Based Costing model developed to the factory. The thesis is wind up by including chapter five with outline information to the developed visual basic programming using ABC principles. Finally a conclusion and recommendation is drawn out from the executions of the study in chapter six. The most concrete result of the whole process is a database with visual basic programming working on ABC-model. The model can be used as a tool of daily management. It has been used to find out the costs of each activity and operation. This has enhanced the cost awareness of the unit. The model can also be used for simulation. It can be used to find out the profitability of the operation of the factory.
Simulation of Solar Cereal Dryer Using Trnsys
(Addis Ababa University, 2007-01) Tkubet, Habtamu; Assefa, Abebayehu (PhD)
In many countries of the world, the use of solar thermal systems in the agricultural area to conserve vegetables, fruits, coffee and other crops has shown to be practical, economical and responsible approach environmentally. Solar heating systems to dry food and other crops can improve the quality of the product, while reducing wastes produce and traditional fuels - thus improving the quality of life. However the availability of good information is lacking in many of the countries where solar food processing systems are most needed. This work presents the performance of several individual, medium and large-scale food processing systems, which incorporate solar drying. A general purpose of solar crop dryer for drying of various agricultural products such as coffee, fruits, Vegetables, cereals, etc, is simulated. The simulated solar dyer consists of the solar air heater ( solar collector) which uses low emissivity glass cover, weather data, and an integrated dryer chamber attached to the collector where the products to be dried are placed. A thermal solar collector model is developed to determine the available useful energy for heating the ambient air with the available solar radiation. Basic heat transfer equations for single-plate and double glass glazing are drived and techniques for the solution of these questions are presented. A computer program is written to predict the collector outlet temperature, mass flow rate and other engineering variables from the input of the meteorological data and collector parameters and also done for the dryer chamber by using the input from the collector out put and the properties like initial moisture content, initial temperature of cereals and other engineering properties. Results of the system simulation are presented in graphical form suitable for system performance determination. From the incident flux, ambient air temperature and solar collector parameters, the useful energy, collector output temperatures of the out put air are determined. Simulation of Solar Cereal Dryer Using TRNSYS i x The output properties of the collector are the input parameters for the drying chamber. These parameters are used to determine the moisture content, the relative humidity, the mass of water vapor and the output temperature of the air at the out put of the drying chamber.
Concurrent Engineering and Implementation A Case Study in Addis Engineering Center
(Addis Ababa University, 2007-02) Moges, Alemu; Reddy. K, Prabhakar (Assistant Professor)
Course Title: Industrial Engineering Design Seminar
(Addis Ababa University, 2007-02) Tekle, Workneh; Chandra (PhD)

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