Browsing by Author "Runyoro, Joseph J."
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Item Critical Gate Velocity for Film-Forming Casting Alloys; A Basis for Process Specifications(1997) Runyoro, Joseph J.; Boutorabi, S. M. A.; Campbell, J.Item Effect of Molten Metal Pressure in the Pouring Basin on Fins Casting in the Mould Cavity(2009) Runyoro, Joseph J.The need for thin-wall castings continues to grow as it is driven by the demand to improve performance and reduce production costs. Thin wall parts can be produced with good dimensional accuracy and controlled physical and microstructure properties. They present special challenges both in preventing misruns, cold shuts and other related casting defects. Experimental work has been carried out using water models to find the contribution of the liquid metal pressure in the pouring basin on the filling of fins in the mould cavity. The results show that the molten metal pressure in the pouring basin has a profound effect in the filling of horizontal fins in metal castings, and formulae for liquid flow through capillary tubes have been presented.Item Effect of Restrained Hot Spots and Integrity of Steel Welded Joints(2010) Runyoro, Joseph J.The need for quality control is paramount especially when new technologies are used with sourced labor as to minimize construction costs. The cost of quality control amount more than 10% of the total construction project cost and assures the client of getting a product of controlled quality. In structures joined by welding processes, a change in welding, transportation or operating procedure may lead to joint failure. In this article, welded joints failures has been documented and it has been observed that failure can occur due to the change in welding procedure in the case of the weld neck flanged pipe joints, or by fatigue failure initiated during transportation of equipment or by change of type of fuel in the case of the boiler.Item The Effect of Tightening Torque on Anchor Bolts Embedded in Concrete(2010) Runyoro, Joseph J.The use of steel anchor bolts is common in concrete structures for holding down steel structures and equipment. The mechanical and chemical properties of concrete differ to that of steel necessitating them to be used with care. They anchor bolts suffer from corrosion formed in concrete, and their failure depends on concrete quality. Work was carried out to ascertain the suitability of anchor bolts for supporting the power generating plant after being in the structure, exposed to the weather for more than five years. Study was also carried out on anchor bolts which failed during installation. During the study, the mode and cause of failure was determined. The study shows that tightening of the bolts by the use of torque wrench imposes torsion stress on the bolts. It was found out that the tensile strength of concrete is low and is the function of compressive strength. A formula for calculating tensile strength based on the quality of concrete has been proposed and is proportional to the square root of compressive strength. A relationship between applied torque and elongation during tightening of the anchor bolts in concrete foundation follows a polynomial curve, and it has been observed that it is difficult to relate the applied torque with the tensile strength of the bolt. The profile of the pulled out concrete due to tightening of anchor bolt is in form of logarithmic curve before recessing at the surface. There exists a threshold of torque required before the bolt start elongating. Steel anchor bolt tightening torque in concrete foundation is almost half to that of steel to steel. In testing number of bolts, the R-squared value and constants of each plotted graph of a bolt test values may be used to quantify the quality of bolt/concrete connection.Item Geometrical and Mathematical Modelling of Running Systems(1993) Runyoro, Joseph J.Item The Running and Gating of Light Alloys(1992) Runyoro, Joseph J.; Campbell, J.