Table of contents

ICESW2017

PREFACE

This is a proceeding of the 1^st International Conference on Engineering for Sustainable World (ICESW).

ICESW brings together international experts, scholars, policy makers, industrialists, etc to discuss contemporary and cutting-edge research in engineering management, innovation, energy development and clean technology. It also provides a golden opportunity to meet experts and develop new collaborations on the fundamentals, applications and products from various fields such as: sustainable energy, sustainable cities, engineering innovations, clean technology/production, sustainable materials and engineering, mechatronics, renewable energy systems etc. The conference strives to foster new collaborative and interdisciplinary relationships among emerging and established engineers, scientists, and policy makers.

All papers published in this volume of IOP Conference Series: Materials Science and Engineering have been peer reviewed through processes administered by the proceedings Editors. Reviews were conducted by expert referees to the professional and scientific standards expected of a proceedings journal published by IOP Publishing.

The study investigated the effect of the use of 0.04%Ni/R134a nanorefrigerant as working fluid in a vapour compression refrigeration system designed to work with hybrid power source of grid-electricity/battery/solar power. The nanoparticle was prepared via the one step method and dispersed into the mineral oil. R134a was employed as the base refrigerant and the performance of the system with the nanorefrigerant was compared, in terms of the coefficient of performance, pull down time and power consumption, with that of the base refrigerant. The results showed that the refrigeration system performed better with the nanorefrigerant as working fluid with any of the power sources and also with the hybrid solar/battery power. The system with nanorefrigerant performed better with improved coefficient of performance in the range of between 7.05% when used with solar/battery as power source and 14.12% when with only battery as power source. The system's pull-down time showed far better results with the nanorefrigerant compared with base refrigerant. However, the system with nanorefrigerant slightly consumed more power with the highest consumption being 28.7% (with battery only as power source) higher that that with the base refrigerant. Based on the outcome of the results, the system can be deployed for vaccine preservation in off-grid remote arears, and also for domestic and commercial applications.

In this Research, the microstructure and mechanical properties of Zn-TiO₂ nano-composite, co- deposited on low carbon steel substrate were fabricated by electrocodeposition route. The structural performance of the composite coating was evaluated by scanning electron microscope (SEM) equipped with energy dispersive spectrometer (EDS). The mechanical property was carried out using a Durascan hardness tester. The result showed that the influence of TiO₂ nano particles greatly enhanced the hardness behaviour. The increase in hardness is ascribed to the uniform homogeneity and dispersion stability of particles in the aqueous solution containing the nano composite.

In majority of industrial applications zinc electrodeposition has been widely used for the corrosion resistant coating on steel due to its unique properties, low cost and sacrificial nature. Steel remains the most widely used material in most applications due to its excellent properties but its faults cannot be over emphasis in term of deterioration. A thin film of Zn on steel substrates was prepared by electrodeposition technique using incorporated rare earth metallic composites to form an optimised bath plating solution. Quaternary Zn-Ni-MoO₂-NbO₂ alloy coatings, as a potential replacement for Zn-Ni coatings were deposited from an acid sulphate solution. The mechanical wear and corrosion behaviours of Zn-Ni-MoO₂-NbO₂ Coated Mild Steel in 3.65% NaCl are described; these were studied by means of MTR-300 dry abrasive wear and polarization measurements respectively. The crystal particles present were observed by X-ray diffraction pattern (XRD) and energy dispersive X-ray diffraction spectrometer (EDS). The microhardness of deposited plate were investigated by means of Vickers microhardness. Scanning electron microscope and was used to study the surface morphology, and synergistic influence content in bath on surface morphology revealed that morphological changes observed in presence of additives exhibits synergistic influence on improving corrosion resistance and hardness of the deposit.

Corrosion processes are responsible for huge losses in industry. This deterioration of components results in loss of plant efficiency, total shutdown and aggressive damage in a number of industries. Though organic, inorganic and mixed material inhibitors were used for a long time to combat corrosion, the environmental toxicity of inorganic corrosion inhibitors has prompted the search for organic corrosion inhibitors. In search for this, the use of organic inhibitors is one of the best options of protecting metals and alloys against corrosion as it is environmentally acceptable, inexpensive and readily available. In this regards, silicon oil was used as inhibitor in this study. Weight loss, corrosion rate, inhibition efficiency and potentiodynamic polarization techniques were used in this study. The aluminium alloy samples exposed to the inhibitor showed a lower corrosion rate values and excellent polarization resistance as compared with the corrosion rate samples without inhibitor. The corrosion inhibition rate increases with increasing the concentration of the silicone oil. The adsorption isotherm was confirmed by Langmuir adsorption isotherm.

Laser metal deposition process is an additive manufacturing process that can produce three-dimensional part through material addition. It that belongs to the class of directed energy deposition. This technology is still fairly new and some of the physics of the process is not fully understood. In this study, the influence of the processing parameter, namely: the powder flow rate, on the resulting physical property of laser metal deposited titanium alloy powder on titanium alloy substrate was carefully investigated. The powder flow rate was varied between 1.44 g/min and 7.2 g/min while the laser power, the gas flow rate, the laser spot size and the scanning speed were maintained at constant values of 3 kW, 2 l/min, 2mm and 0.004 m/s respectively. The laser metal deposition experiment was conducted using a 4.0 kW Nd: YAG laser. The surface roughness was measured using Jenoptik surface analyzer. The results showed that the surface roughness increases when the powder flow rate was increased. The minimum average surface roughness value of 4.5 μm was achieved at the lowest powder flow rate of 1.44 g/min. The low roughness value obtained at lower powder flow rate could be attributed to proper melting of the powder at these settings.

The whole facilities at the Palabora Copper (PTY) Ltd (PC), Limpopo, South Africa (i.e. both existing and new) are under obligation to comply with the new plant MES by the 1^st of April, 2020. At the moment all processes on the PC mine conform to the MES for existing plant with the exception of the copper smelter and the associated sulphuric acid plant. Despite considerable investment by PC over the last few years in equipment and maintenance, due to the short comings of the copper smelting technology employed on site, certain relevant MES have proven to currently be unachievable. The generation of the waste CSD is considered a global issue and at PC the direct smelting process option is the recycling method currently being used to manage the generated waste CSD at the copper smelting plant. This recycling method is neither cost effective nor energy efficient and it leads to the production of worthless residues. As a result, an enhanced hydrometallurgical based recycling process option is recommended as an appropriate recycling process option. Hence, it was concluded that an industrial scale centrifugal separator like the Knelson or Falcon concentrators be stationed in the existing and proposed plants as a separate but integral part of the ore processing system, so as to reduced/removed the reactive materials it often contains before subjecting it to a hydrometallurgical and Nano technological processing, in order to recover the copper value in it as precipitates of nanoparticles.

The effects of quenching medium on the impact behaviour of mild steel welded joints were investigated, single – vee butt welded joint was employed in welding the samples. The welding was carried out at 100A and at a terminal voltage of 140V (14kW), using gauge 8 coated electrode (4mm size) throughout the welding processes. Four (4) quenching media were employed which are Brine solution (0.1 Molar concentration), two (2) Litres of water, two (2) Litres of diesel oil and abundant air. 8mm thick mild steel bars were used for the heat treatment process at variable annealed temperature steps of 200⁰C – 400⁰C – 600⁰C. The Izod impact machine was employed in carrying out the Impact Test. The results obtained from the test carried out show that quenching in brine solution gives least average impact strength while normalized in air gives highest average impact strength and is the mildest of all the quenchants. The overall results show that air was the best medium for quenching welded mild steel followed by diesel oil, then water and lastly brine solution for quenching welded parts or components under influence of impact or sudden loading. The results will enable engineers, welding personnel and roadside welders select the best and most economic quenchant that will be best suitable for quenching welded components or parts made of mild steel subjected to impact or shocking loading.

In this study, pyrolysis of sawdust sample (Western blood-wood- Eucalyptus terminalis) was investigated. Experiments were performed at six temperature levels ranging from 300 °C to 800 °C under N2 atmosphere. The weights of char, tar and gas yields produced in each experiment were measured and recorded in percentage of initial weight of the pyrolyzed sample. Results of the study showed that product yield of Eucalyptus terminalis char, tar and gas of 41.28% at 300 °C, 45.10% at 300 °C and 57.20% at 800 °C, respectively were produced. Proximate analysis shows that volatile matter, fixed carbon, ash content and moisture content of sawdust sample were 75.53%, 15.35%, 1.56% and 7.56%, respectively. Result of the elemental analysis shows that the carbon, hydrogen, nitrogen, oxygen and sulphur contents of the sawdust sample were 54.19%, 7.05%, 0.97%, 37.15%, and 0.64%, respectively. The higher heating value and pH of the sawdust sample are 23.40 kJ/g and 2.30% respectively. This indicate that char and tar yields decrease with increased pyrolysis temperature while gas yield increases as pyrolysis temperature increases for the sawdust sample. The value of the correlation coefficient obtained indicate a fairly high degree of accuracy of the regression models to predict experimental result when used within the temperature range considered in this study. Result of analytical Py-GC/MS shows that the proportion of phenolic compounds identified was more than 50% with trans-2-octadecadecen-1-ol, cis-10-pentadecen-1-ol, 9-octadecenal and methyl-1-cyclohexenyl ketone dominating. This study establishes the fact that pyro-oil can not only be used as a fuel but can also be purified and serves as raw materials for chemical and processing industries.

Clay has been widely used as a raw material in construction and in the building sector from the ancient period till date. It is a sustainable material and the technology of processing it can be found anywhere in the world. As a result of its sustainability, it can be used in many industries. One of the products derived from clay is roofing tiles. Some of the properties to be considered are thermal and durability of the materials, are necessarily to be taken into consideration, especially if the building needs to be situated in tropical region. Clay seems to be a good choice. This paper will therefore, assess the possibility of using clay from south west and aluminum dross as composite roofing tiles. Clay samples were collected from five (5) deposits in Igboora (Oyo), Ilaro, Itori, Ajegunle in (Ogun) and Ikorodu in (Lagos) states in south west of Nigeria. The clay samples were crushed, pulverized and sieved. Their chemical compositions analysis was carried out using Atomic Absorption Spectrometer (AAS); molds 135mm by 120mm by 15mm were made for the clay samples. Composites were made in the following proportions by a mix of clay samples with aluminum dross in a percentage ratio of 50:50 and another mixture of clay samples with aluminum dross and bentonite as a binder at a percentage ratio of 45:45:10. The physical properties such as water absorption and cold crushing strength were carried out. Also thermal conductivity was carried out on the sample. The result of chemical analysis showed that Igboora, Silica (47.9%) an alumina (36.7%), the rest were the traces or the other element. Ilaro samples were silica (43.5%) and alumina (34.2%) Itori samples, silica (49.8%) and alumina (30.7%). Ajegunle sample, silica (46%) and alumina (38.2%) and Ikorodu sample, silica (54.5%) and alumina (24.6%). These results were compared to the Grim-Shaw specifications which specified (25.45%) alumina and 40.6% silica compositions in requirements for clay soils ascertained that the samples were all clay soils, though the Ikorodu samples was lacking a little in its alumina content. The result of water absorption test of Igboora samples and its composite agree with the Indians roofing tiles' standard (IS 654:1992) while the other samples failed. The result for Ilaro composite 50:50 had the lowest thermal conductivity of 0.086w/m.kg for the crushing strength test, the Itori and Ilaro composite with bentonite acting as binder produced results of 1.07KN and 1.01KN which agrees with the Indian roofing standard. At this preliminary work, it can be suggested that in conclusion, Igboora and Ilaro clay and their composites seem to be promising for roofing tiles.

Looking at African Development in comparison with other continents, it can be concluded that there are still so much to do to achieve comfortable standard of living for the majority of the inhabitants. While a lot of steps has been taken and appreciable progress has been made in many places, majority are yet to have access to stable and affordable basic necessities of life such as potable water, stable electricity and comfortable accommodation. This study examined various engineering approaches being used and those that could be used to make the enumerated basic necessities of life accessible to majority of Africans at affordable price. Our evaluation revealed appropriate lifecycle engineering as a feasible approach to achieving the desired goal. This research and its findings will assist Africans and other nations in understanding African infrastructure problems and how best to address the technical problems in a sustainable manner.