O. M. Popoola

The Effects of Silicon Carbide Reinforcement on the Properties of Cu/SiCp Composites

Copper, possessing a desirable combination of high electrical and thermal conductivities is widely used in thermal and electronic applications. The prospective requirements for dependable materials in electronic industries are always increasing.. The main pronounced failure that occurs during microelectronic circuits’ application involves thermal fatigue. Heat generated in electronic packages can be dissipated by developing suitable materials as heat sinks. Copper metal matrix composites reinforced with silicon carbide (SiC) proffer possibility of meeting these demands. This research work entails producing copper matrix using silicon carbides (SiC) as reinforcement. Copper silicon carbide composites were produced in 80 % Cu-20 % SiC, 70 % Cu-30 % SiC, 60 % Cu-40 % SiC, 50 % Cu-50 % SiC, 40 % Cu-60 % SiC ratios with an average grain size of 212 μ m, 425 μ m and 710 μ m respectively via liquid metallurgy method. The result revealed that increasing volume fraction and particle sizes of the particulate had significant effect on the thermal and electrical conductivity of the composites.

Inhibitive Action of Ferrous Gluconate on Aluminum Alloy in Saline Environment

The corrosion of aluminum in saline environment in the presence of ferrous gluconate was studied using weight loss and linear polarization methods. The corrosion rates were studied in different concentrations of ferrous gluconate 0.5, 1.0, 1.5, and 2.0 g/mL at 28°C. Experimental results revealed that ferrous gluconate in saline environment reduced the corrosion rate of aluminum alloy at the different concentrations studied. The minimum inhibition efficiency was obtained at 1.5 g/mL concentration of inhibitor while the optimum inhibition efficiency was achieved with 1.0 g/mL inhibitor concentration. The results showed that adsorption of ferrous gluconate on the aluminium alloy surface fits Langmuir adsorption isotherm. The potentiodynamic polarization results showed that ferrous gluconate is a mixed type inhibitor. Ferrous gluconate acted as an effective inhibitor for aluminium alloy within the temperature and concentration range studied. The data obtained from weight loss and potentiodynamic polarization methods were in good agreement.

Residential Lighting Modelling: ANFIS Approach in Comparison with Linear Regression

Most practices applied in the development of lighting usage profile do not reflect the complexity occupants have on lighting loads in residential buildings. This study involves the use of Adaptive Neural Fuzzy Inference System (ANFIS) and regression model for residential load usage profile development, prediction and evaluation for energy and demand side management initiatives. Three variables namely natural light, occupancy (active) and income level were considered in this study. A better correlation of fit and reduced root mean square error was obtained in comparison with the regression model. The developed approach (ANFIS) has the ability to give better lighting prediction accuracy in relation to non-linearity data and behavioural tendencies.

The Influence of Heat Treatment and Process Parameters Optimization on Hardness and Corrosion Properties of Laser Alloyed X12CrNiMo Steel

Martensitic stainless steels are used in the production of steam turbine blades but their application is limited due to low hardness and poor corrosion resistance. Laser surface alloying and heat treatment of X12CrNiMo Martensitic stainless steel was conducted with the aim of enhancing hardness and corrosion properties. A Rofin Sinar Continuous Wave Nd: YAG solid-state laser was used to alloy the specimens. The electrochemical and hardness properties were studied using potentiodynamic polarization technique and Vickers micro hardness tester. The microstructures of the as-received, post-heated and pre-heated specimens were investigated by a Scanning Electron Microscope (SEM) and Optical Micrograph (OM) respectively. From the experimental results, the post-heated specimens exhibited the highest hardness property as compared to all other specimens. There was also significant improvement in the corrosion resistance of the post heated specimen compared to all other specimens and the substrate as evidenced by higher polarization resistance and lower corrosion rates. From the analysis of grey relational grade model, the significant laser processing parameters were identified. The results showed the influence of laser power and scanning speed on the corrosion rate, hardness and alloyed depth. The predicted results were found to be in good agreement with the experimental results.

End-use Appliance Control Technique for Domestic Peak Load Management

Several peak load management strategies are being widely employed in the residential sector, due to increased energy consumption and peak demand. The residential peak demand is very prominent and largely depends on the interaction between occupant’s energy consumption behaviour and appliance usage, hence the need to address end-use appliance usage based on consumer utilization pattern. This paper presents a domestic peak load management model using end-use appliance control technique, with focus mainly put on reducing demand and energy consumption whilst ensuring that the consumer’s needs are met to a certain degree during peak periods. The proposed technique uses a bottom-up approach to capture the diversity and variability of various end-use appliance energy profiles in the household based on the consumer usage pattern. Empirical time of use (ToU), frequency of appliance usage and appliance power characteristics are the variables considered in the proposed methodology. Results obtained from simulation of proposed control model shows that the system is practically realizable using Matlab/Simulink and this is expected to contribute towards peak demand and energy usage reduction. This eventually will cumulate into reduced electricity costs for consumers and utility operational expenditure.

Electrodeposition of Functional Coatings on Bipolar Plates for Fuel Cell Applications – A Review

The issue of corrosion and degradation has been evaluated as one of the major sour‐ ces of concern in the history and trend of materials development and their applica‐ tions in engineering. Design, process, and production consideration of materials hinge on the motive of built-to-last technology in their lifetime applications. The “World Corrosion Organization” has calculated that the direct cost of corrosion worldwide is over 3% of global gross domestic product (GDP)—approximately US

Modelling of middle income residential lighting load profile using a universal estimator

2.2 trillion—every year. Natural materials tend to return to their original stable states after being conformed through processes into engineering applications. In order to conserve materials’ in‐ tegrity, usability, safety, and performance, the materials have to be subjected to processes that will keep them in its optimal functionalities. The finishing phase of most materials for engineering applications is usually done with protective barrier in the form of coating, paint, or furnishes to conserve the materials’ integrity and inhibit its susceptibility to interact with the environment. Complete overhauling of a whole corrosion-invaded device is capital intensive. Corrective maintenance through repair work on damaged parts is not economically viable. To minimize or avoid these costs, adoption of functional composite coatings using electrodeposition can be effective. Bipolar plate of fuel cell is a key performance component with corrosion challenge. This chapter will focus on electrodeposition as one of the corrosion inhibition tech‐ niques on bipolar plate of fuel cell [1, 2]. Through electrodeposition, bipolar plate can be protected with appropriate functional coatings to enhance surface quality and impart good surface properties that will prolong lifespan application in fuel cell vehicles.

Nd: YAG laser treatment of aluminium —C TiB2 coated: Optimization of corrosion properties

The intricacies of the impact occupants have on lighting loads in residential buildings are not reflected in most practices use for light usage profile. This investigation involves the use of a universal estimator (Adaptive Neuro Fuzzy Inference System (ANFIS)) for middle income lighting load usage profile development, prediction and evaluation) for energy and demand side management initiatives. Natural light, Occupancy (active) and Income level are the three factors considered in this study. Trapezium membership function was applied during the training process of the ANFIS model due to historical light usage pattern (time of use) data. The result obtained after validation of the developed model using the investigative data showed a better correlation of fit and root mean square error in comparison with the regression model. The developed approach has the ability to give better lighting prediction accuracy in relation to non-linearity data and behavioural tendencies.

The effect of multiple laser alloyed tracklines on the corrosion properties of Al-MMC

As the reports in the literature regarding corrosion performance of Al/TiB2 MMC are rather contradictory, the optimization of laser surface alloying parameters for these composite coatings seems to be necessary. The characterization of the MMC was carried out by optical microscopy (OM), scanning electron microscopy (SEM/EDS) and x-ray diffraction (XRD). Partial melting of the alloying powder occurred and the chemical reactions with the a-Al in the matrix led to the formation of AlTi and AlB2 phases. Eutectics of TiB2/Al and TiB2/Ti were observed. The results of the tests indicate that TiB2 reinforcement does not give significant increase in microhardness of aluminium. The corrosion resistance of a single laser trackline MMC in a 3.65 % NaCl solution was improved, especially for the sample produced at high scan speed, with the lowest volume fraction of TiB2 particles.

On-line automatic switching of consumers' connections for improved performance of a distribution feeder

In real life engineering applications, production of large area coverage is often required especially for preventing material loss and component damage. To enhance such applications, multiple tracklines laser surface alloying of Al/TiB2 was performed to obtain a large area coverage using Nd:YAG laser. The overlap rate was 50%. The characterization of the metal matrix composite was carried out by optical microscopy (OM), scanning electron microscopy (SEM), and x-ray diffraction (XRD). Results indicated that the microstructure consist of high concentration of TiB2 distributed in the solid solution at front zone of the tracks corresponding to the overlapped region while the track centers contain similar microstructure but with lower content of TiB2 as indicated by energy dispersive spectrometry (EDS). This microstructure is basically similar to that of a single alloyed trackline, but with different percentages of TiB2 reinforcement. The measured microhardness of the overlapped sample decreased with about 11....