Masters Degree Dissertations

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Support vector machine approach in selection of welding method for grey cast iron
(Kyambogo University [unpublished work], 2023-09) Okure, Robert Omita
Grey cast iron is the utmost common form of cast iron. It is used in applications where its high stiffness, machinability, vibration dulling, high heat capacity and great thermal conductivity are of advantage, such as in automobile components especially for internal combustion engine cylinder blocks, flywheels, gearbox cases, manifolds, disk brake rotors and cookware. It therefore contributes a lot to the socio-economic and technological standards of any country. With its unique properties such as; easy castability, vibration reduction, high stiffness and high thermal conductivity, repair of grey cast iron steel requires careful consideration when selecting the correct welding method from the many techniques available. This study is focused on developing a tool for selecting appropriate welding methods for grey cast iron. Two common welding methods; Oxygen-acetylene Gas welding and Shielded Metal Arc Welding, were evaluated in respect of the critical factors that affect weld quality like: type of joint, filler material and the carbon composition of the material. It was observed that Arc welding a butt joint with a cast iron electrode gave very high tensile strength of 116.04N/m2 hence very good joining. On the other hand, gas welding a lap joint with Mild steel gave the least Tensile strength of 31.22N/m2 signifying a poor-quality weld. A support Vector machine (tool) was then developed to choose the most applicable method of welding grey cast iron, basing on the three attributes; joint, filler material and carbon composition. Results showed that a Non-linear Support vector machine was the most appropriate, as it was able to identify the most appropriate welding method in all cases. The non-linearity in the attributes was identified to come from the filler material, which was associated with microstructure cracking. Results from the Support Vector Machine were compared to that from the popular TOPSIS (Technique for Order of Preference by Similarity to Ideal Solution) method which was able to classify only 75% of the welding methods correctly. A non-linear support vector machine model can be applied to help welders to identify the appropriate welding technique.
Performance analysis of the top rollers in a sugar mill using finite element method
(Kyambogo University[unpublished work], 2022-08) Kasambula, Vicent
Sugar milling is the process of extracting juice from crushed sugarcane fibres for production of sugar crystals. The three-shaft sugar mill set consists of the top roller and two bottom rollers to crush the sugarcane. The top roller shaft is the main crushing shaft of the sugar mill which is directly attached to the prime mover so it rotates and is loaded. Therefore, the top roller shaft in the mill set is subjected to more torsion and bending stresses. This study examined the mechanical performance of four top rollers under dynamic loading in four mill sets 1-4 of the sugar plant. To achieve this, firstly, the forces on the top rollers were determined and stresses on the top rollers were analysed using the maximum shear stress method to determine the unsafe loaded zones of the top rollers. Secondly, camera photos were obtained for visual inspection, detailed micrographs of the failed surfaces were obtained for microstructural examination; and the chemical composition and hardness of the failed components were determined and compared with known material standards for the top roller bare shafts, roller shells and couplings. Thirdly, geometrical models of the top roller were generated using solid works and transferred to ANSYS workbench which was used to analyse the maximum displacement, fatigue sensitivity, safety factor and equivalent alternating stress for the subjected dynamic loading in sugar milling; monotonic and cyclic parameters of forged steel were used for the bare shaft and parameters of ductile cast iron were used for the roller shell. The results of the shear stress analysis, microstructural characterization, and chemical composition and hardness of the failed top rollers showed that material non-conformance contributed to shaft failures. Maximum displacement, fatigue sensitivity and equivalent alternating stress showed that failure occurs at shoulders, key-way and shaft square ends; and top rollers in mill sets 3 and 4 are more susceptible to failure than top rollers in mill sets 1 and 2. The study evaluated the fatigue performance of top rollers in sugar mills. Keywords: Top Roller Shafts, Dynamic loading, Shear Stress, Alternating Stress, Mechanical Performance.
Utilization of ferric oxide generated in the acid regeneration plant in paint making (case study: roofings rolling mills ltd, Namanve, Kampala)
(Kyambogo University (unpublished work), 2021-03) Mafabi, Peter
This study investigated the utilization of ferric oxide generated in the Acid Regeneration Plant (ARP) of the steel galvanizing line as an ingredient in making paint. The waste acid liquor generated from the process of pickling the steel sheet surface with an acid to remove stains, rust and dust before galvanizing is pumped to the reactor tanks of the ARP where it is heated using oxygen and steam to very high temperatures varying between 370°C - 700°C. The by- product of the reaction in the reactor is ferric oxide that is not utilized and is openly disposed in landfills which is hazardous to human health and the environment. In this study, several experiments and observations were carried out on random samples of the ferric oxide generated from the ARP to ascertain whether its properties were close to that of the ferric oxide sold on the market so as to establish the potential use of the ferric oxide generated in the ARP in paint making. The chemical and physical properties of ferric oxide generated in the ARP were analyzed, the ferric oxide was then neutralized, and its potential utilization in paint making was demonstrated. The analysis of the ferric oxide obtained from the ARP showed presence of the chloride ion which is responsible for the acidity of the ferric oxide making it unsuitable for making paint. The ferric oxide was neutralized by mixing it with water and manganese IV oxide and the mixture heated to temperatures above 100oC until a yellowish gas was given off giving neutralized ferric oxide residue of the pH in the range of 6.98 – 7.19. The neutralized ferric oxide was used as a dye in paint and it was concluded that ferric oxide generated from the ARP can be neutralized and gainfully utilized as a dye in paint in manufacture of ferric oxide paint. This leads to attainment of a cleaner environment through reduced open disposal of ferric oxide, reduced ferric oxide disposal costs, and minimize air pollution with reduced inhalation of hazardous fumes by humans.
Design of a heating, ventilating and air-conditioning system that utilizes multiple condensing units in the refrigeration circuit
(Kyambogo University (unpublished work), 2019-11) Walugembe, Brian
The heating, ventilating and air conditioning system performs a critical role in pharmaceutical products manufacturing by majorly providing thermal comfort and acceptable indoor air quality, conditions required for the production. efficacy and stability of the products. What motivated this study was downtime the HV AC system is likely to be subjected to. An HV AC system, just like any :functional system is bound to be subjected to downtime, which is majorly because of the refrigeration loop. This downtime problem was approached by using the action research methodology, where after problem identification, steps were taken to design and model an HV AC system that not only eliminates the chilled water loop but also incorporates multiple condensing units of the same capacity in the refrigeration loop. This was done with the idea of providing backup for the major components of the refrigeration loop i.e the condensing units to minimize downtime. However, this is no mean feat owing to the fact that assembling refrigerant compressors in series is not an option since these compress a vapor into a liquid and, should a liquid be introduced into the compressor, one runs the obvious risk of damaging the compressor, which is expensive, and time consuming to replace. Despite a new design of the HV AC refrigeration loop being developed. care was taken to ensure that the modified system does not lose its characteristics that enable it to perform the other :functions of an HV AC system. The physical model designed, constructed and installed answered the research question that multiple condensing units can be incorporated on a single refrigeration circuit. Validation of the installed system proved that the system is capable of attaining the thermal comfort requirements required for pharmaceutical products manufacturing. Lastly, a comparison with a conventionally designed HV AC system was made and in a four month time period, the conventional HV AC system had experienced down time totaling to 24 hours as a result of failure of components in the chilled water loop. This is dangerous to the products as it poses a risk of compromising production, efficacy and stability of the manufactured products. The new design gives HV AC design engineers an edge while designing HV AC systems for minimal
Determination of cooling effects on tensile strength of re-bars using spray quenching
(Kyambogo University (un published work), 2019-08) Omara, Walter Louis
In this study, the tensile strength in carbon steel was achieved under controlled heating and cooling processes. Forty-five samples of billets were used to produce 12 mm, 16 mm and 20 mm of hot-rolled rebar and each rebar was accorded different heat treatment process. The treatment process involved spray quenching by varying the coolant flow rate and coolant temperature at 250C, 350C, and 450 C where the flow rate was controlled using pressure flow meter at 5Kgf/cm2, 10 Kgf/cm2, and 14 Kgf/cm2. The samples for chemical analysis were prepared according to RRM-QA.WI-07and analyzed using the mass spectrometer. The tensile test specimens were prepared according to ASTM E8/E8M-13 and tests were conducted on the Universal Testing Machine. Microstructure analysis was carried out on the specimens obtained from samples using standard methods on a metallurgical microscope(Krussoptronic VOPC93) equipped with a camera of 3.0 megapixels. The analysis of chemical composition revealed that the samples are of low carbon steel with 0.233 wt.% C, 98.3 wt.% Fe, 0.746 wt.% Mn, 0.313 wt.% Si and other alloying elements. The results of the study showed that a pressure flow of 10 Kg f/cm2, and coolant temperature of 35℃, is sufficient to cool a 12 mm, 16 mm and 20 mm rebar and obtain UTS values of 648 Mpa, 604 Mpa& 557 Mpa respectively which falls within 550-650 Mpa, as stipulated in the Ugandan Standard and East African Standard(US & EAS 412-2:2013). The results showed reduced strength for all rebar sizes at low-pressure flow of 5 Kgf/cm2and high coolant temperature of 450C. The microstructure of the specimen showed that a matrix mix of pearlite and ferrite exists in the structure. The more the pearlite in the mixture, the more the hardness with increased strength and reduced percentage elongation, while the more the ferrite in the matrix mix, the less strength it exhibits and increased percentage elongation with less brittleness. The study also showed that for a 12 mm, 16 mm & 20 mm rebar, requires a range from 33.50C to 44.50C at 10 Kgf/cm2 to 14 Kgf/cm2, 35.50C to 44.50C at 6.8 Kgf/cm2 to 13.2 Kgf/cm2 and 260C to 430C at 6.3 Kgf/cm2 to 13.3 Kgf/cm2 respectively to produce UTS of 648-556 Mpa, 554-643 Mpa and 558-645 Mpa respectively. Implementation of these research results will help to reduce rejects of rebars and improve on financial loss of RRM. Key words; heat treatment, spray quenching, mechanical properties, hot rolled steel bar
Enhancing a sustainable safe water supply for rural communities of Mabungo parish, Kisoro district
(Kyambogo University (un published work), 2019-07) Kwitegetse, Penlope
Access to safe water is still a challenge in Africa, the biggest population that suffers the challenge being from sub-Saharan African countries where Uganda is part. The major cause of limited water access is that 85% of water supply systems stop supplying water after a short while from time of implementation. The situation escalates the water crisis forcing people to use raw water from the available water bodies. This involves trekking very long distances coupled with the risk of acquiring water-borne diseases. This study focused on Mabungo parish, in Kisoro district, and investigated the factors that influence sustainable supply of water systems in the area. Data was collected from 269 respondents within Kisoro district using questionnaires. The sustainability of the potential scheme in the Mabungo parish was also tested using the participatory research method, which came up with a community based model for sustainable water supply for the communities. The results confirmed Kabiranyuma scheme to have potential for supplying Mabungo communities with safe water to the required level of sustainability. Adopting a participatory approach among communities of Mabungo, has high opportunities of contributing towards achievement of sustainable development goal 6, which aims at ensuring universal access to clean water and sanitation by 2030. The approach prepares rural communities to manage their water supply systems themselves during and after implementation. Though full involvement of communities in operating and managing a water supply is the main way to ensure proper functionality and sustainability, It is important to note that, support from Local Government, the responsible Ministry or external entities in form of finance, technical back stopping, operational infrastructure, regular supervision, among others can do a great deal in boosting their performance. Communities were encouraged to practice rain water harvesting to be used as a supplementary water supply in the study area. Keywords: Rural communities, water access, sustainability, enhancement, safe water
Investigations into the mechanical performance of Ugandan made carbon steel bars
(Kyambogo University (un published work), 2019-08) Ssempijja, Deo
Carbon steel bars are one of the most used steel products in structural constructions worldwide. Ugandan steels have been reported to have significant amounts of residual elements due to use of scrap steel in their production. Variations in carbon content have been reported in the Ugandan made reinforcing steel bars made from scrap raw material indicating a lack of chemical composition control. Therefore, to ascertain the compliance with quality standards, this study investigated the mechanical performance of Ugandan made carbon steels bars (20mm TMT ribbed bars) focusing on chemical composition, microstructure, tensile strength, and bendability. A comparison of the results with the requirements of the quality standards BS 4445: 2005 and the East African standard, EAS 412 - 1: 2005, based on ISO 6935 were used to establish the performance of the Ugandan made steel bars. Three (3) steel producing companies were considered based on their annual production capacity. In order not to identify the steel companies chosen, the companies were coded as A, B and C. A total of nine (9) steel bars of 20mm diameter were used in experiments. Three (3) bars were picked from the distributors of each of the steel producers selected. A spark emission spectrometry was used for chemical composition analysis, photo Microscopy of x500 was used for microstructure analysis and a universal tensile testing machine was used for both tensile strength and bendability tests. The carbon equivalent value (CEV) ranged between 0.363% and 0.374% for company A, 0.307% to 0.323% for company B and company C between 0.347% and 0.397% which are within acceptable range according to BS 4445: 2005 standards ranging 0.3 to 0.55%. There were variations in the microstructures of steel bars. The tensile strength (UTS) alternated between 640N/mm2 and 714N/mm2, the yield strength (YS) extended between 538N/mm2 and 600N/mm2, UTS/YS ratio was between 1.252 and 1.195 and the percentage elongation 18% to 22%. The values were all within the acceptable range according to BS 4445:2005 standards. The maximum bending force needed to bend to 900 was found to be 52235N with a maximum deflection of 74.4mm. The Steel bars exhibited bending stress with a range of 148 N/mm2 to 166 N/mm2. The general mechanical performance of the 20mm steel bar had acceptable quality standards basing on BS 4445: 2005 and the East African standard, EAS 412 - 1: 2005, based on ISO 6935 but with variations in carbon equivalent values. Key words: carbon steel bars, chemical composition, microstructures, tensile strength and bendability
Impact of investiment in occupational health and safety on a steel manufacturing plant in Uganda
(Kyambogo University [ Unpublished work], 2021-07) Bwengye, Innocent
The subject of health and safety of workers in the steel manufacturing sector has become a concern of recent mainly in developing countries. The study therefore sought to investigate the impact of investment in health and safety on steel manufacturing companies in Uganda, a case study of Roofings Rolling Mills in Namanve Industrial area. The aim of the study was to identify the different health and safety preventive measures that have been put in place, examine the costs associated with OHS measures and work-related incidents, determine the qualitative and quantitative benefits of the OHS intervention measures and finally find out how health and safety affect the employee’s productivity using regression analysis. A descriptive survey study was adopted as the research design. Review of incident cases registers, hazard identification and risk assessments forms, employee compensation claims, records for lost workdays was done. Simple random and judgmental sampling techniques were used to select subjects from each plant to give data on how health and safety affect the productivity measures of quality, work output, attendance and one’s morale. The data on productivity measures, accident prevention costs, accident costs was analyzed both qualitatively and quantitatively using the IBM SPSS VESION 26 and Microsoft excel. The findings of this study show remarkable reductions in injury numbers, lost workdays, and this translates into low injury costs and this is linked to be direct benefits of occupational safety and health measures. For every one percent increase in OHS measures, the benefit in terms of reduction in direct injury costs is between 2 to 8 percent and this was consistent with other studies. From the coefficient estimates of regression analysis, both work quality and quantity increase by 76.6 percent, the morale of employee increases by 76.7 percent while the attendance improves by 76.2 percent. The marginal increments in the productivity measures due to a unit increase in safety are; 27.6 percent for one’s presence, 28.2 percent for work quality, 28.3 percent for individual’s work output and 26.8 percent for one’s morale. The coefficient of determination (R square) is 0.49 which shows that productivity is 49 percent influenced by the health, safety and the rest 51 percent is explained by other factors which were not considered in the study. The findings help the employer not to look at the expenditure associated with OHS measures as a cost but rather as an investment with return and not to make decisions on whether any changes will bring cost saving but whether it will protect workers. The findings will help the organization to reduce the levels of risk at different plants.
Characterisation of resistance spot welding Electrodes with annular recess design
(Kyambogo University (un published work), 2018-11) Apora, James
This study investigated the characteristics of resistance welding electrode with annular recess design for supplying an electric current to metallic workpieces for welding two workpieces together. It comprises cylindrical body of an electrically conductive material (copper) having an annular recess tip for contacting workpiece. The tip is formed with a recess which gave the tip annular workpiece contacting surface. The recess was filled with an electrical and heat resistant material containing ceramic cement known as kaolin mixed with clay. The novel idea of the tool design is to enable formation of molten material pool which forms weld nuggets with even strength around the joints. The beginning facts about the recess design tool is that the annular recess minimizes current and voltage concentration in the middle of the tool tips, thereby; causing molten materials to flow both to the centre and onto the perimeter of the spot welded joint where the welding pressure is applied. Studies have shown that conventional spot welding tools produce joints which are stronger on the edges but weaker in the centre of the nuggets which presumably experience high voltage concentration. The data collection was done through RSW welding experiments where welding of sheet metal materials with same thickness was carried out; alloy steel materials cut from a salvage vehicle were used to make the sample strips measuring 50mm by 175mm each. The design and manufacture of annular recess was carried. The welded joints were subjected to different tests to characterize the weldability and integrity of the welded joints. The tests involved destructive testing and non-destructive tests of the joints. Magnetic Particle Inspection (MPI) was used to test the weld joint integrity beside the visual inspection. In this research study, effect(s) of electrode tip geometry on the tensile-shear strength in resistance spot welded joints of metal steel sheet (body panel) cut out from an old salvage vehicle of similar thickness (1mm) was studied. The outcome of this study showed remarkable improvement on the tensile-shear strength of RSW joint with a nugget diameter about 8.1mm by approximately 11.4KN using the annular recess electrodes compared to 5.7KN at nugget diameter of 7.8mm using the conventional electrode. The annular recess electrode provided an enhanced joint strength by approximately 2 times than the conventional electrode. Therefore application of this new technique creates a new tool that can enhance RSW joints strength in metal fabrications and also improvement on the crash worthiness of the vehicle. Keywords: Current, Electrode, Nuggets, Resistance, Spot-welding,
Optimization of packaging operations for beer production line efficiency : case study packaging line 1, Nile breweries limited
(Kyambogo University, 2018-11) Matende Nkwoleke, Richard
In light of the need for beer production plants to foster competitiveness in today‟s beer market, Nile Breweries Limited packaging beer line 1 factory efficiency dropped from 83.25% in January 2015 to 56.8% in January 2018 due to availability losses, performance losses and quality losses. Through optimization of packaging operations to improve line efficiency above 83.25%, by identifying bottlenecks, determining efficiency loss caused by bottlenecks and optimizing line 1 using lean manufacturing tools, a sample survey research design was carried out. Through observations, qualitative and quantitative data was collected to identify bottleneck machines using stop watch and data gathering worksheet. Data was analysed using fishbone method, graphs and tables. Depalletizer and palletizer machines were identified as bottleneck machines with efficiency drop from 135% V-profile efficiency to 109% and 120% respectively and general line efficiency loss of 18.8%, hence causing a total financial loss of USD 1,174,378.377 by January 2018. Through detailed implementation of unified theory for lean manufacturing tools, line balancing and adopting new preventive maintenance strategy, waste reduction measures are proposed in order to improve machine performance and factory efficiency above 89% and 83.25% respectively.
Assessing impacts of climate change on hydrological extremes of Rwizi catchment
(Kyambogo University, 2019-11) Baraza, Gerald
There is lack of understanding on the impact of climate change on hydrological extremes of Rwizi Catchment. This threatens the sustainability of water to support socio- economic activities in the Rwizi Catchment. The procedure for conducting the study was guided by three objectives. Firstly, Trend analysis showed that precipitation mainly increased whereas Potential Evapotranspiration (PET) exhibited a decrease. The trend in both precipitation and PET were mainly insignificant. The second objective focused on establishing the climate change signals on precipitation and PET based on Global Circulation Models (GCMs) from Coupled Model Inter-comparison Project phase 5 (CMIP5) outputs. This was done by considering the Representative Concentration Pathways 4.5Wm-2 (RCP4.5) and 8.5Wm-2 (RCP8.5) scenarios. The precipitation and temperature of the 2050s and 2080s were projected to increase as to compared to the control period (1956–2002). Two conceptual hydrological models were calibrated and used for the impact assessment. Their difference in simulating the flows under future climate scenarios were also investigated. For the Austrian Water Balance Model (AWBM), the assembled mean projections of the high flow of 10- year return period for the 2050s and 2080s were projected to decrease. Whereas, for the Hydrological Model focusing on Sub-flows’ Variation (HMSV), the assembled mean projections of high flows were projected to increase. The results for the low flows reveal decreasing low flow quantiles for AWBM for the 2050s and 2080s. However, for HMSV model, it showed increasing low flows quantiles. These impacts of climate change on the river flow show the need for a careful planning of relevant and appropriate adaption measures at a catchment scale. Keywords: Climate change, Climate models, Hydrological models, Rwizi Catchment.
Utilization of top aluminum-zinc dross in the manufacture of pervious concrete
(Kyambogo University, 2018-11) Batia, Stephen
Dross is a waste product from the galvanizing process that contains useful substances in large percentages that can be harvested and transformed or reused in production processes to earn a profit. Dross from Roofings Rolling Mills Ltd galvanization process is harvested from the galvanizing bath, cast into blocks and sold to companies that have the technology to extract and process the valuable elements they contain. Though dross from Roofings Rolling Mills Ltd is sold off to other industries that need it, the economic value generated from its sale is not commensurate to the number of valuable products trapped in it. The enormous number of useful products in dross can be utilized in the development of previous concrete slabs to be used in water seepage applications. Top Al-Zn dross from Roofings Rolling Mills Ltd was analyzed to determine its physical and chemical properties. Top Al-Zn dross was beaten when hot at temperatures below its melting point with a sledgehammer to reduce its size, sorted into three different sizes and mixed to come up with top Al-Zn dross samples. Top Al-Zn dross samples were mixed with portland pozzolana cement and water of weight 50% mass equivalent of cement to develop top Al-Zn dross/ portland pozzolana cement slabs. The developed top Al-Zn dross/ portland pozzolana cement slabs were further subjected to tests of density, porosity, coefficient of permeability and compressional strength. Top Al-Zn dross from Roofings Rolling Mills Ltd was composed of mainly aluminium and zinc with traces of other elements combined to form different compounds that are responsible for the variations in the hardness value across its surface. Top Al-Zn dross samples, portland pozzolana cement and water mixture on casting foamed with a noticeable rise in temperature, with porosity confirmed in all the top Al-Zn dross/ portland pozzolana cement slabs. The analysis of top Al-Zn dross/ portland pozzolana cement slabs revealed varied physical properties depending on the amount of top Al-Zn dross added in the mixture, for instance, density, porosity, and permeability increased with further addition while the compressional strength after seven days of curing reduced. The coefficient of permeability of top Al-Zn dross/ portland pozzolana cement slabs varied inversely with the compressional strength. Top Al-Zn dross/ portland pozzolana cement slabs produced from a mixture containing 39% top Al-Zn dross possessed a combination of both maximum coefficients of permeability and compressional strength. From the results of the experiment conducted, top Al-Zn dross from Roofings Rolling Mills Ltd can be used as a foaming agent when mixed with portland pozzolana cement and water to develop slabs that can be used for water seepage applications. Further development of top Al-Zn dross/ portland pozzolana cement slabs should be investigated with uniformed sized top Al-Zn dross particles and with the addition of other ceramic materials wastes like broken bricks, tiles, etc. The costs involved in development of top Al-Zn dross/ portland pozzolana cement slabs should be further studied including the analysis of water filtered through them to determine the level of toxicity.
Effects of power interruptions on quality and production in a galvanizing plant Case study: roofings rolling mills ltd, Namanve, Kampala
(Kyambogo University, 2019-11) Atima, Rose
Steel is the most used engineering material industries. In Uganda, Roofings Rolling Mills Ltd (RRM) is the largest steel manufacturer; with mega industrial undertakings which is in line with national economic development strategy as it employs 2,000 people in the country. However, this is undermined by the negative effects of electric power interruptions. Thus, evaluation of the effects of power interruptions on quality and production in the sheet galvanizing plant was done in accordance to specific objectives to; determine the process parameters that influence the galvanizing; determine the effect of power interruptions on the process parameters; and assess the cost implications of power interruptions on the galvanizing line at RRM. During this study, the most affected processes were identified, damages were quantified and costs related to this effect were determined. To this effect the organization can negotiate for tax reduction levy due to the losses caused by power interruptions. The methods used were quantitative and qualitative, for determining the parameters influencing galvanizing. The various types of rejects, their causes and evaluating how power interruption affects quality and production which in turn affects the organizations performance. This was a success by participatory observation in accordance to a checklist, literature reviews and relating these to the set standards (ISO, ASTM, AGA, UNBS, etc.). To obtain results data analytical techniques (tables, regression analysis and Anova). Analysis have shown that, to obtain high quality products, there is need to ensure that parameters for galvanizing are in accordance to standards. The study showed that color coating and cold galvanizing are the most affected processes. The study shows the different effects of power for 2016 and 2017 on cold galvanizing line as; rejects from 5% to ( 25.35% and 0.77%), machine efficiency from 94% to (87.76 and 91.7%), production efficiency from 92% to (69.17% and 78.8%) for these years respectively. These resulted to increase in production costs, from UGX 7.5 billion per annum to UGX ≈ 8.65 billion per annum, amidst other investment challenges affecting the organization’s performance. For improved performance, the affected lines need alternative power sources supplied to help always clear the products online in case of any power interruption, there is need to have alternative power to clear product on line and conduct risk assessment for the safety of workers, equipment and machinery during power interruptions. Furthermore, it’s recommended, that the organization applies for connection to stable power supply line that will reduce on production losses. This will lead to more profits for the organization, thus economic benefits to the government and fulfilling “Uganda’s Vision 2040.’’
Development of a mathematical model for integration of robots in a steel manufacturing plant
(Kyambogo University, 2021-07) Adoko, Ongom Christopher
The use of computer-controlled robots is increasingly picking up in today’s manufacturing industries. Industrial robot application in manufacturing industries allows for improved flexibility and configurability required for providing product variability. However, in technologically low developed countries, steel manufacturing tasks in steel industries are mainly executed manually. Due to the demand for improved product quality, productivity, safety, and reduction in manufacturing costs, there is a need for these plants to integrate robots into the operations. Two automated steel manufacturing Plants A and B, consisting of three manufacturing cells were considered during the research. The aim was to study the material handling systems used in each manufacturing cell, the material storage systems, steel manufacturing processes, the adaptability of each manufacturing cell to new technologies, and the current steel manufacturing technologies to identify manufacturing tasks suitable for robot integration. A systematic robotic integration process in steel manufacturing industries by utilizing a Markov decision model was developed. A finite-state Markov decision process model for robot automation decision was formulated while considering specific tasks to be accomplished by a robot in a given manufacturing cell. The Markov chain formulated represented states of robot performance under automation policies. The material handling cost matrices represented the long-run measures of each manufacturing cell performance for the Markov decision process problem formulated. The aim was to determine an optimal robotic automation decision for each manufacturing cell to minimize the long-run material handling costs for the given state of performance. Computational efforts using the Markov decision process approach provided promising results for material handling cost minimization for both steel plants and the replacement of humans with robots at the zinc pot reduced the average waiting time and increased the line utilization rate. The overall steel processing time correspondingly decreased by about 63% compared to the existing manufacturing cell. Robot integration in both steel plants presented solutions for reducing labour costs, material-handling damage, improving the productivity of automated steel manufacturing systems, and overall safety of the steelworkers. However, it is desirable to extend the research to analyse the impact on the non-stationary performance of a robot on the decisions taken. There is a need to expand the model to consider automation options for minimum material handling costs in the context of Continuous-Time Markov Chains (CTMC). The assumptions made during the simulation study did not consider worker fatigue and machine breakdowns. The justification of the proposed model by considering worker fatigue and machine breakdowns is an area of further research in this field of study.

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