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The structural, mechanical and thermodynamics properties of cubic zirconium oxide (cZrO 2) were investigated in this study using ab initio or first-principles calculations. Density functional theory was used to optimize the crystal structure of cZrO 2 and thereafter, simulations were conducted to predict the lattice parameters and elastic constants. The Zr-O bond distance was calculated as 2.1763 Å with unit cell density of 6.4179 g/cm 3. The data obtained were used to determine Young's modulus, bulk modulus, Poisson's ratio and hardness of cZrO 2 as 545.12 GPa, 136.464 GPa, 0.1898 and 12.663(H v) respectively. The result indicates that cZrO 2 is mechanically stable with thermodynamics properties of a refractory material having potential for structural and catalytic applications in various forms as a nanomaterial.

The single-walled zirconia nanotube is structurally modeled and its Young’s modulus is valued by using the finite element approach. The nanotube was assumed to be a frame-like structure with bonds between atoms regarded as beam elements. The properties of the beam required for input into the finite element analysis were computed by connecting energy equivalence between molecular and continuum mechanics. Simulation was conducted by applying axial tensile strain on one end of the nanotube while the other end was fixed and the corresponding reaction force recorded to compute Young’s modulus. It was found out that Young’s modulus of zirconia nanotubes is significantly affected by some geometrical parameters such as chirality, diameter, thickness, and length. The obtained values of Young’s modulus for a certain range of diameters are in agreement with what was obtained in the few experiments that have been conducted so far. This study was conducted on the cubic phase of zirconia having armchair and zigzag configuration. The optimal diameter and thickness were obtained, which will assist in designing and fabricating bulk nanostructured components containing zirconia nanotubes for various applications.

This work presents the conceptual design of a gas distribution pipeline network for estates in Nigeria using the University of Abuja Staff Quarters as a case study. The problem statement was the aggressive consumption of cooking gas, referred to as liquefied petroleum gas (LPG), without gas pipeline networks infrastructures to homes and estates across Nigeria but relies on cylinders with its attendant danger. The methodology includes the determination of the gas demand from the average monthly gas consumption in each of the households, the elevation head, diameter of the pipelines, gas velocity, gas mass flow rate, head losses and the pressure drop analysis of series (option 1), parallel (option 2) and grid (option 3) options. The results obtained indicate that the best gas distribution design option for the trunk, reticulation and service pipelines was the grid connections to minimize investment costs with equitable pressures at service outlets. In the selected design option, the total length of the 50.8 mm diameter trunk pipelines was 19.52 m, while the total length of the 12.7 mm diameter reticulation and service pipelines were 3,223.34 m and 1,648.46 m respectively. The quantities of fittings required for the pipeline network layout were determined for an estate of 124 houses. The mass flow rates of the LPG in the 3 pipeline sections were found to be 0.39 kg/s and total head loss based on local resistance coefficients was found to be lowest in option 3 (1,568.33 m), which also has the least pressure drop of 67.84 kPa in the trunk and reticulation pipelines. It can be concluded that the optimized design could be adopted for the gas distribution pipeline network of University of Abuja staff quarters and other estates in Nigeria, with similar elevation and buildings layout.

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