Key Engineering Materials Vol. 917

Abstract: The erstwhile transformer oil material, for all these periods of more than two centuries, has been championing liquid dielectrics, for machines’ cooling and insulation purposes. However, its use has detrimental and attendant consequences on global terrestrial and aquatic habitats, industries and global warming. Palm oil (Elaise Guinensis Eg; and/or Elaise Oleifera Eo) is presently posing a great challenge to liquid hydrocarbon in the operation of transformers. Despite the ease in availability of mineral oil today, especially for oil producing nations, this paper aims at unveiling its several underscores and analyses of the viscosity, flash point, density, neutralisation (acidic value) number, electrical resistivity, and breakdown voltage (BDV) results of the respective mineral and palm oil samples. Palm oil’s test results values of approximately, 244OC, 55kV and 0.004 mgkOH/gm of oil, was recorded, respectively for the flash point, breakdown voltage (BDV) and acid neutralisation index, as compared with corresponding mineral oil’s values of 142OC, 59kV and 0.004 mgkOH/gm. The results obtained favoured the use of palm oil than the mineral oil for transformer’s operation.

Abstract: Refrigerants are commonly used as heat transfer fluid in refrigeration, heat pumps, and air conditioning systems. Nanorefrigerants are a special kind of nanofluid synthesized by dispersing nanoparticles into refrigerants or lubricant oil to improve its thermophysical and heat transfer characteristics. The optimization of the thermophysical properties of nanorefrigerant strongly depends on the successful synthesis procedures used for producing a stable suspension of nanoparticles in the refrigerants. In this study, a review was carried out to understand the synthesis of nanorefrigerant and the effect of nanoparticle size, type and concentration, temperature, base fluid type on the thermophysical properties of the nanorefrigerant. The effect of nanorefrigerant on the pressure drop and boiling heat transfer within the vapour compression refrigeration system (VCRS) was reviewed. From the review, the thermophysical properties of the nanorefrigerants affect the pressure drop and heat transfer characteristics of the vapour compression refrigeration system.

Abstract: Lubricants are commonly used in machining and energy system to reduce friction and wear within moving parts and aid in the transfer of heat. The use of lubricants enhances the overall performance and operation life of systems. Synthetic lubricants commonly used are non-biodegradable and are harmful to aquatic and land habitats. To overcome these challenges, biolubricants from vegetable and animal sources were considered as an alternative to synthetic and mineral lubricants. In this study, the esterification and transesterification processes were used to produce biolubricant from castor oil. Methanol and sulphuric acid (H₂SO₄) were used as alcohol and catalyst respectively for the acid catalysed esterification while ethylene glycol and sodium hydroxide (NaOH) were used for the transesterification process. The average biodiesel yield was 99.87%. The two-step method was deployed in the preparation of the castor nanobiolubricant. The nanobiolubricants were prepared using aluminium oxide (Al₂O₃) nanoparticles of 20 – 30 nm nominal diameter. The volume concentrations of 0.1%, 0.2%, and 0.4% were used in the preparation of the nanobiolubricants. The results showed that the addition of Al₂O₃ nanoparticles into the castor oil biodiesel altered the thermophysical properties (density, dynamic viscosity, pH, acidity, free fatty acid (FFA), flash point, and cold properties) of the biolubricants. The addition of Al₂O₃ nanoparticles reduced the acidity, flash point, and pH value of biolubricant while the cold flow property was improved. The dynamic viscosity decreased with an increase in temperature and increased as the nanoparticle concentration increased. The results were compared with the thermophysical properties of mineral oil, and from these analyses, Al₂O₃ nanobiolubricant can be successfully deployed as an alternative to synthetic and mineral lubricants in machining and energy systems. Fourier transform infrared (FTIR) and UV-Vis analyses were conducted on the castor oil, its biolubricant, and nanobiolubricants.

Abstract: This study was carried out to ascertain the optimum parameters for maximum total acid number (TAN) reduction via catalytic esterification using chicken eggshell ash as catalyst. A central composite design (CCD) was created to optimize TAN reduction by varying temperature and catalyst weight %. The chicken eggshell ash was calcined and reactivated in a furnace at 900 °C for an hour. An oil solution (referred to as synthetic solution) of diesel was adulterated with the organic acid m-toluic which served as a representation for highly acidic oil. Titration using alcoholic potassium hydroxide (KOH) and an indicator (phenolphthalein) was used to deduce the total acid number of the synthetic solution before and after esterification. The optimum parameters for maximum TAN reduction obtained from the model were a temperature of 56.90 °C, a catalyst weight % of 11.45%, and a maximum TAN reduction of approximately 94%. Fourier Transform Infrared (FTIR) Spectroscopy also confirmed that TAN reduction had taken place as the peaks that represent the carbonyl group (C=O stretch at ~1605 cm-1) was reduced significantly.

Abstract: The need to develop renewable fuels in order to reduce reliance on fossil fuels and mitigate climate change is constantly growing, and biofuels can solve the problem. Moreover, research into ecologically friendly and sustainable energy fuels such as biodiesel is rapidly gaining momentum. The yield response of parsley biodiesel was evaluated by the utilization of calcium oxide which is a solid heterogeneous catalyst. The impact of catalyst loading, alcohol: oil ratio and temperature on the yield of parsley biodiesel was also assessed. The obtained result from the experimental analysis revealed that a high biodiesel yield of 96.5% can be obtained using 3 wt% of catalyst amount, 60 °C temperature of the reaction, and 9:1 alcohol-to-oil ratio at a fixed reaction time of 180 minutes. The biodiesel generated was characterized using gas chromatography-mass spectrometry (GC-MS). Additionally, the fuel properties of biodiesel were well within the ASTM D6751 requirements. As a result, parsley biodiesel can be used as a diesel fuel alternative.

Abstract: The search for a perfect replacement for fossil fuels is as a response to the decrease in the available energy owing to the overdependence on the fossil fuels as well as the harmful effects on human life due to the release of toxic gases into the air as it burns in engines. The experimental study carried out in this article evaluates the possibility of parsley biodiesel as a suitable substitute for petro-diesel. The catalytic conversion of a novel feedstock with a homogenous catalyst was performed with specific ratios of catalyst amount (1 wt %), temperature (60 °C), alcohol to oil ratio (6:1) for 30 minutes reaction time. However, a biodiesel yield of 94.70% was derived from the adopted parametric conditions. Gas chromatography-mass spectrometry (GC-MS) was utilized to characterize the produced biodiesel. Furthermore, the fuel characteristics of biodiesel were within the specifications of the ASTM D6751. Therefore, Parsley biodiesel can be utilized as diesel fuel substitute.

Abstract: The strength of a fine-grained lateritic soil from three (3) different locations on Abuja – Lokoja road where road failure occur was treated with sodium silicate activator (SSA), cement and rice husk ash (RSA) with varying percentage scrutinized by means of Atterberg, compaction and triaxial shear tests. The result reveals that cement additive improved the lateritic soil from Liquid limit values of 41.25 at 0% to 44.36 at 8%, but reduces at 10% to 35.67, while RHA increases at increased percentages. The MDD improved with increase in the quantities of all the additive (SSA, cement and RHA) content, while OMC for both cement and RHA reduces from 18.65% at 0% to 11.71 and 18.05 respectively. It reveals cohesion of the soil at 0, 2, 4, 6, 8 and 10% to be 19, 39, 49, 55, 58 and 65 KN/m² respectively, with highest angle of 65⁰ and lowest of 37⁰. This implies that the cohesion of the improved sample was satisfied since the improved angle of internal friction is above the angle that makes soil very plastic which is 28⁰. Keywords: Geopolymer. Sodium silicate, rice hush ash, Triaxial, Abuja.

Abstract: This research paper approaches a new insight toward reducing the manual, mechanical and codependent systemization as an upcoming trend for architectural sustainability and autonomous power providing. By describing some new methods of applied and tested functional features through enhancing or rearrange the properties of ordinary and composite materials in the field of build and construction, it demonstrates a new prospect of wider investments in innovative material production in architectural design and actuation. Also, reveals new methodologies for individual and non-linear autonomy to providing long-term maintenance in extreme conditions or sudden damages as a supportive capability for the used materials to be adopted in design processes.

Abstract: The pioneers of the industrial revolution, and their successors, left the world’s ecosystem in a devastating state. Global warming became the consequence of activities in the industry that led to climate change, the depletion of the ozone layer, and pollution of the ecosystem. For decades now, concerned researchers have been frantically investigating methods and procedures that can help conserve the ecosystem's left to attain sustainability. The construction industry also poses its challenge as novel solutions to construct sustainable, less hazardous products to the environment and improve human health are diligently investigated and identified yearly. This paper discusses specific steps of this nature and explains how environmentally-friendly construction methods and materials produce ceiling boards.