Modelling the Effects of Friction on Tool-Chip Interface Temperature During Orthogonal Cutting of Al6061-T6 Aluminium Alloy

© IEOM Society International - IEOM 2019In this work, finite element simulations based on the analytical model derived with the MATLAB software were used to establish the temperature fields within the cutting tool and tool-chip interface. The average tool-chip interface temperature model was simulated and the simulation results were compared with experimental results for validation. At a maximum cutting speed of 90 m/min, the maximum temperature obtained from the experiment was 410 oC, at same rake angle of 0o. However, the developed model predicted 490 oC under the same conditions. The higher value obtained by the model can be attributed to the negligence of heat losses to the surrounding by both convection and radiation modes, as an assumption in the formulated model. A similar trend of these results was also recorded for the case of rake angle and feed rate of 30o and 0.0635 mm/rev, respectively. It was observed that the simulation results and experimental measurements for the average tool-chip interface temperature agreed significantly.Final Published versio

Study of Rake Face Action on Cutting Using Palm-Kernel Oil as Lubricant

The work investigates the effect of cutting speed, feed rate, depth of cut, and rake angle on main cutting force during the cylindrical turning of mild steel, brass, and aluminum rod, using high speed steel cutting tool and palm-kernel oil as cutting fluid. The impact of lubrication on the coefficient of friction between the chip and rake face during turning operation, assuming a negligible friction between the flank and cut surface is measured. Experimental results show that aluminum at cutting speed of 4.15m/s and rake angle 9o gave a 33.3% reduction in coefficient of friction while brass and mild steel under the same cutting condition gave7.9 and 13.8% increase in coefficient of friction respectively. Findings at cutting speed of 4.15m/s and depth of cut 1.5mm gave 9.79% reduction, 46.7 and 20.8% increase in coefficient of friction for brass, aluminum and mild steel respectively while cutting speed of 4.15m/s and feed 1.8mm/rev gave a 9.2% reduction, 30.4 and 14.5% increase in coefficient of friction for brass, aluminum and mild steel respectively. Similar trend was observed by varying the cutting conditions on the workparts through different selected values. The effect of palm-kernel oil as a metal cutting lubricant is more pronounced on aluminum than brass and mild steel

Plug Flow Analysis for the Design of the Compaction Region of a Tapered Screw Extruder Biomass Briquetting Machine

The study of compaction or solids conveying in a screw extruder has been carried out majorly on the straight screws using the plug flow analysis. Despite this, the analysis of the straight screw appears to be complex as contained in existing literatures based on the force and torque balance. The tapered screw, which is considered to be an effective option for biomass compaction, introduces greater complications because the geometry is constantly changing. In this study, a method based on the traction and retardation mechanism of friction is developed for a fully unwound screw channel utilizing only the force balances. The procedure has been used to carry out a parametric analysis of the tapered screw extruder for a screw press biomass briquetting machine. The taper angle was considered to significantly increase the pressure developed in the extruder depending on the length of the compaction zone. The optimum taper angle has also been found to be dependent on the frictional coefficient of the biomass material with enclosing surfaces and ranges between 2° and 4°

DEVELOPMENT OF A VARIABLE SIZE NUT CRACKER

In this work, a variable size nut cracking machine has been designed and constructed to improve the efficiency of shelling operation of quite a number of nuts. The machine is designed to be adaptable to the cracking requirements of some number of nuts, whose shell can be processed to brittleness. The machine performs two operations, shelling of the nut and separation of the shell from the nut. The machine comprises of a hopper, rectangular box housing the cracking drum and compression plate, and a two stage agitated separating tray (to sort the nut from the shell), all supported by a frame. The cracking drum, which is driven by a v-belt connected to an electric motor, also provide the agitation to the separating tray via a v-belt connected a cam mounted shaft that helps push the tray against stationary springs to return the tray to its initial position upon the dwell of the cam. The continual return and compression of the tray against the spring subjects the tray to a vibration needed to enhance the travelling of the shell-nut mixture over it. The machine was tested with palm kernel, the strongest of the class of nuts it was designed to crack; the machine yields a cracking efficiency of 87%. The whole kernel recovery of the machine stands at a magnificent value of 87%. The machine performed satisfactorily

Potentials for Generating Alternative Fuels from Empty Palm Fruit Bunches by Pyrolysis

The threat that the disposal of empty palm fruit bunches constitute to communities in oil palm processing areas in Nigeria coupled with the current global focus on alternative energy is the trigger for this work. An existing pyrolytic reactor consisting of a reactor unit, condensate receiver, copper pipe connectors and gas receiver was modified and adapted for converting empty palm fruit bunches to alternative fuels. The average char yield was 44.9%, and the percentage of feedstock converted into pyrogas and tar oil was 55.1%. The char yield decreased gradually as temperature was increased from 300-700°C. Char yield was highest (39.78%) when the temperature was 300°C and the lowest char yield was 25.05% at 700°C The calorific values of char ranged between 21.12 and 23.76 MJ/kg. Apart from the potential of generating energy from pyrolysed EFB, it abates the disposal problem that EFB constitutes in the oil palm industry

Development of a Cashew Nut Cracking Device

Rosana G. Moreira, Editor-in-Chief; Texas A&M UniversityThis is a paper from International Commission of Agricultural Engineering (CIGR, Commission Internationale du Genie Rural) E-Journal Volume 9 (2007): Development of a Cashew Nut Cracking Device. Manuscript PM 06 030. Vol. IX. June, 2007

Investigating the lateral stability of three-wheeled scooter taxi due to tyre-road forces

Three-wheeled scooter taxi (TWST) that is currently prevalent in developing countries, is fuel efficient and cheap. It is used mainly for commercial purposes, also as a means of reducing unemployment and tackling poverty. However, the vehicle is unstable and prone to accidents due to its design configuration. The aim of this research work is to investigate the lateral stability of TWST due to Tyre-Road Forces. Therefore, lateral stability equations for three-wheeled vehicle (TWV) were developed and used in the analysis of TWST based on parametric values obtained from static test. The results showed that the vehicle is stable with respect to lateral stability, which is in line with what was obtained from literature, thereby validating the models with the driver alone. However, with two or more occupants the vehicle became unstable. Possible ways of eliminating this instability were discussed. The static test procedure, if adopted and legislated upon, would significantly enhance safety of life and properties of stakeholders in developing countries. Keywords: Three-wheeled scooter Taxi, Stability Analysis, Safety of life and properties, Legislation

Analysis of Cost Estimation and Wind Energy Evaluation Using Wind Energy Conversion Systems(WECS)for Electricity Generation in Six Selected High Altitude Locations in Nigeria

Two commercial wind turbines namely AN Bonus 300 kW/33 and AN Bonus 1 MW/54 were technically assessed for electricity generation in six selected high altitude sites spreading across the North-West and North-East geopolitical regions of Nigeria by computing their capacity factors, annual power and energy outputs. The economic evaluation of using the two wind energy conversion systems (medium and large) for electric power generation in the selected locations were also estimated using the present value cost method. The results showed that capacity factors of the two turbines in the selected sites ranged between 4.6 and 43%. Average minimum cost per kW h was obtained in Kano as $0.0222/kW h with AN Bonus 1 MW while the highest average cost is$0.2074/kW h with AN Bonus 300 kW in Kaduna. The highest cost in each of the location was obtained with the medium WECs (AN Bonus 300 kW). In addition, Kano and Katsina were also found to be very economical for any of the adopted wind turbine models. Gusau and Kaduna, at cost of unit energy of about $0.30/kW h were found to be more profitable for non-connected electrical and mechanical applications (water pumping, battery charging) than diesel generator

Small hydropower (SHP) development in Nigeria: An assessment

This paper evaluates small hydropower (SHP) development and examines the current situation in Nigeria with respect to the established policies and Energy Power Sector Reform (EPSR) Act 2005. Hydropower sector witnessed about 360% growth between 1971 and 2005 and yet only about 5% of the vast small hydropower (SHP) potential is tapped by the few plants built between 1923 and 1964. Operating and maintenance costs are in favor of SHP development in the country, being the lowest when compared with the situation in European countries. The Nigerian Government has taken steps to diversify energy sources in order to promote renewable energy development by encouraging private investments in the energy sector through reforms, but this may not be adequate as there remain barriers against SHP development in the country. It is concluded that government must incorporate subsidies, feed-in-tariffs, and framework for Price Purchase Agreements (PPA) into the policies in order to further promote renewable energy and attract both indigenous and foreign investments for quick adoption and rapid expansion of SHP technologie

Youth perception on yahoo-yahoo (cybercrime) : a case study of Ado-Ekiti, Ekiti State Nigeria.

Master of Social Sciences in Criminology and Forensic Studies. University of KwaZulu-Natal. Durban, 2017.The study examines the perception of youth on cybercrime which has been on the increase in recent time as a new nomenclature “yahoo-yahoo”. The breakthrough in technology comes with its attendance consequences which include cybercrime. The study therefore investigates the perceptions of youth on yahoo-yahoo, the factors predisposing youths to participation, gender peculiarities and the ways in which social media attitudes influence the phenomenon. The theoretical orientations that guided the study were strain theory and Rational Choice Theory. The study was conducted in Ado Ekiti, Ekiti state capital. The study adopted qualitative research method as it empirical approach of inquiry. It purposively sampled the opinion of 20 youth with the aid of a semi-structured interview schedule. Findings from the study shows that yahoo-yahoo a form of cybercrime is perceived to be something fraudulent and a crime perpetrated with the aid of internet. Factors such as poverty, unemployment, corruption, peer pressure, greediness, and get rich quick syndrome are responsible for why youth engage in yahoo-yahoo. It was also noted that females are also involved in the acts just as their male counterpart. However, the percentage of females involved in yahoo-yahoo is lower compared to the males. It was also discovered that the various social media display has influence youth involvement in yahoo-yahoo. The study therefore concludes that social factors of unemployment, poverty and corruption are the major precipitators of cybercrime. Hence there is a need for a concerted effort by the government and other stakeholders to work assiduously at solving the various social problems bedeviling the nation and thereby combating the menace of cybercrime