Impact of Monetary Policy on Exchange Rate in Nigeria: Bound Test and ARDL Approach

The aim of this study is to examine the relationship between monetary policy and exchange rate in Nigeria. The results of past empirical studies have not shown a clear direction about the nature of relationship between these variables in the country and these studies have failed to utilize the methodology in this work, which has created a gap in the literature. Data was collected from the Central Bank of Nigeria Statistical Bulletin from 1990– 2016 and various diagnostic tests such as Unit Roots and Bound Tests were carried out. Consequently, ARDL model was utilized to address the objective of this study. It was discovered in this study that credit reserve requirement and Treasury bill rate have a negative relationship with exchange rate. However, monetary policy rate and broad money supply have a positive relationship with exchange rate in the country. Furthermore, due to these important findings, this paper makes the following vital policy recommendations for the monetary authorities, policy makers, financial institutions regulators and future researchers.  Due to the high volatility in exchange rate in Nigeria currently, the monetary authorities should increase the credit reserve requirement of the commercial banks. Also, the Central bank should increase that rate at which it sells Treasury bill to the commercial banks. The multiplier effect of this policy will reduce the level of high powered money and consequently stabilize the exchange rat

Development of Insulating Masonry Bricks from Wood Fiber and Varying Milled Glass Proportion

Thermal efficient sandcrete bricks are masonry units with good thermal insulating properties. Wood fiber (WF) possesses low thermal conductivity, hence, its incorporation in mortar mix results in thermal efficient masonry units. Milled glass (MG) could be added for strength enhancement. This study incorporated WF into mortar mix at a constant dosage of 5 wt.%, with varying MG proportions of 0, 5, 10, 15 and 20 wt.% and cured for 7, 14 and 28 days. The results obtained showed minimization of porosity and water absorption at increasing MG content. Density and compressive strength were enhanced as MG content increased. Flexural and splitting tensile strengths appreciated and peaked at 15 wt.% MG. Thermal performance measured demonstrated progressive appreciation in thermal conductivity while specific heat capacity followed a downtrend as MG dosage increased. The study revealed that the collage of 5 wt. % wood fiber and 15 wt. % MG yielded optimum result. The study, therefore, concludes that the addition of milled glass and wood fiber positively and significantly affected the properties of sandcrete bricks. 15 wt.% of milled glass and 5% wood fiber inclusion in sandcrete bricks are recommended for use by construction practitioners

Optimization of Flexural Strength of Recycled Polyethylene-terephthalate (PET) Eco-Composite using Response Surface Methodology

Recycling and reuse of plastic waste by blending with virgin polymer has been affirmed to be the best way of managing the waste. Equally, agro-waste are best recycled than being burnt off. In the development of stronger and cheaper ecoefficient recycled PET composite for food packaging, this study focused on reinforcement of the blend of 20 wt. % recycled PET (rPET) and 80 wt. % virgin PET (vPET) with snail shell particulate and kenaf fiber via compression moulding process. The process parameters are fiber dosage, particulate dosage, moulding pressure and temperature. Box-Behnken design was engaged in the design of experiment and the samples were produced according to the experimental runs. Result of analysis of variance pinpointed the process factors as significant contributors to the flexural strength response. The model developed was validated to be significant and statistically fit. Interactions between the process variables as revealed by the response surface plots indicated the response was dependent on the interactive pattern between the variables. Response surface optimization showed an optimum flexural strength of 57.16 MPa was attainable at process parameters of 27.27 wt. %, 4.18 wt. %, 3.95 MPa, and 160 ˚C for fiber proportion, particulate proportion, moulding pressure and temperature respectively yielding 34.2 % improvement over the reference 80/20-vPET/rPET matrix. Model validation experiment undergone with the combined parameters and deviation of +0.036 was noted. Since the deviation is insignificant, the model is concluded to be statistically fit for predicting the flexural strength of the developed eco-composite

EXPERIMENTAL STUDY ON THE MECHANICAL BEHAVIOUR OF FIRED SAND-CLAY AND GLASS POWDER-CLAYBRICKS

Mechanical behaviour of fired bricks containing varied amount of fine sand (FS) and waste glass powder (GP) was investigated.FS and GP were added to bricks at varied amount of 0, 5, 10, 15, 20, 25, 30, 35 and 40 wt. %. Firing was done at 1200 oC and samples produced were evaluated for compressive and flexural strengths while microstructural analyses of 25 wt. % FS and GP-clay bricks were examined. Results showed that compressive strength was highest at 30 wt. % GP for GP-bricks while for FS-clay bricks, compressive strength rose to 11.4 and 12.8, at 35 and 40 wt. % FS addition. Flexural strength for GP-clay and FS-clay bricks peaked at 30 wt. % GP (3.63 MPa) and 40 wt. % FS (2.45) respectively. Flexural modulus increased progressively and exponential-ly as FS and GP proportion increased. Work donein resisting deformation and deflection during bending reduced with increased amount inboth additives. Flexural strain was inversely related to load and stiffness. In conclusion, addition of GP and FS in increas-ing amount resulted in improved mechanical properties in the bricks. Also, increased proportion of GP and FS was found to im-prove response to loading in fired bricks

Experimental Study on the Properties of Fired Sand–Clay Ceramic Products for Masonry Applications

This study reports the effect of fine sand addition on the properties of fired clay bricks. Fine sand was sieved to −75 μm and incorporated at varied weight proportions (5, 10, 15, 20, 25, 30, 35, and 40 wt.%) to clay in the preparation of fired bricks. The samples produced were oven dried at 110°C for 12 h, and fired at a temperature of 1,200°C in an electric furnace. The samples were examined for physical, thermal, and mechanical properties. Result of the tests showed a reduction in porosity, water absorption, weight loss, and firing shrinkage with increasing sand addition, although the bulk density increased as the percentage weight content of sand increased. Thermal properties such as thermal conductivity, thermal diffusivity, and thermal emissivity increased with fine sand addition while reduction in coefficient of thermal expansion and specific heat capacity was observed. Also, the thermal shock resistance improved with increase in fine sand addition up to 25 wt.%, before further decline was observed. The hardness and impact value were enhanced with increasing additives. It is noted that samples immersed in rainwater were found to experience depreciation in hardness, resistance to impact, compressive and flexural strengths as the number of days of immersion increased. It was concluded that bricks produced are good for building in temperate region in which much flooding is not experienced

Effect of Surface Modification on the Properties of Polypropylene Matrix Reinforced with Coir Fibre and Yam Peel Particulate

Polypropylene composites reinforced with coir fibre and yam peel particulate were produced using compression moulding machine. Treated and untreated coir fibres were used; 1.5 M NaOH was used for the treated coir fibres. Yam peel was grouped into two, treated and untreated; the treated was modified using 1 M solution of NaOH and HCl in the proportion of 30% and 70%, respectively. 'e yam peel which was sun-dried for 14 days was pulverized and sieved to −45 µm. Samples were developed using treated and untreated reinforcements (TCF/YPP and UCF/YPP) at constant coir fibre proportion (15%) and varied amount of yam peel particulate (2, 4, 6, and 8 wt.%). 'e hybrid composite samples developed were probed for mechanical properties and thermal and wear behaviour. 'e level of particles agglomeration at the fibre-matrix interface was examined using scanning electron microscope. 'e results show that sample reinforced with treated 4 wt.% coir fibre and yam peel particulate had optimum mechanical properties. However, the thermal conductivity of composite samples increased with fibre addition. All composite samples developed had better resistance to abrasion when compared to the control sample

Applicability of Extreme Vertices Design in the Compositional Optimization of 3D-Printed Lightweight High-Entropy-Alloy/B₄C/ZrO₂/Titanium Trihybrid Aero-Composite

Recent studies have shown the benefits of utilizing ceramic particles as reinforcement in metal alloys; nevertheless, certain drawbacks, including loss of ductility, embrittlement, and decreases in toughness, have been noted. For the objective of obtaining balanced performance, experts have suggested the addition of metal particles as supplement to the ceramic reinforcement. Consequently, high-performance metal hybrid composites have been developed. However, achieving the optimal mix for the reinforcement combination with regards to the optimal performance of developed composite remains a challenge. This research aimed to determine the optimal mixture of Al50Cu10Sn5Mg20Zn10Ti5 lightweight high-entropy alloy (LHEA), B4C, and ZrO2 for the fabrication of trihybrid titanium composites via direct laser deposition. A mixture design was involved in the experimental design, and experimental data were modeled and optimized to achieve the optimal performance of the trihybrid composite. The ANOVA, response surface plots, and ternary maps analyses of the experimental results revealed that various combinations of reinforcement particles displayed a variety of response trends. Moreover, the analysis showed that these reinforcements significantly contributed to the magnitudes and trends of the responses. The generated models were competent for predicting response, and the best formulation consisted of 8.4% LHEA, 1.2% B4C, and 2.4% ZrO2

Effect of Surface Modification on the Properties of Polypropylene Matrix Reinforced with Coir Fibre and Yam Peel Particulate

Polypropylene composites reinforced with coir fibre and yam peel particulate were produced using compression moulding machine. Treated and untreated coir fibres were used; 1.5 M NaOH was used for the treated coir fibres. Yam peel was grouped into two, treated and untreated; the treated was modified using 1 M solution of NaOH and HCl in the proportion of 30% and 70%, respectively. 'e yam peel which was sun-dried for 14 days was pulverized and sieved to −45 µm. Samples were developed using treated and untreated reinforcements (TCF/YPP and UCF/YPP) at constant coir fibre proportion (15%) and varied amount of yam peel particulate (2, 4, 6, and 8 wt.%). 'e hybrid composite samples developed were probed for mechanical properties and thermal and wear behaviour. 'e level of particles agglomeration at the fibre-matrix interface was examined using scanning electron microscope. 'e results show that sample reinforced with treated 4 wt.% coir fibre and yam peel particulate had optimum mechanical properties. However, the thermal conductivity of composite samples increased with fibre addition. All composite samples developed had better resistance to abrasion when compared to the control sample

Selected properties of waste wig, eggshell and waste paper hybrid composites as potential material for wall partitioning

Waste wig fibers, empty eggshell powder and waste paper were recycled in the development of composite boards as potential sustainable material for wall partitioning. Samples were produced by blending these wastes with cement in the presence of water and cured for 14 and 28 days. The samples produced were examined for density, porosity, thickness swelling, internal bonding strength, modulus of rupture and elasticity in line with standard procedures. From the result obtained, there was reduction in porosity, thickness swelling, while internal bonding strength and modulus of rupture and elasticity were enhanced. An optimum value for modulus of elasticity was attained at 0.96 g/cm3 (3.85 MPa for 14 day curing and 3.5 MPa for 28 day curing), even as internal bonding strength increases with increasing density. It was therefore concluded that recycling of these wastes is effective in the development of sustainable materials for wall partitioning. � 2021 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the International Conference on Materials, Processing & Characterization