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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. http://dx.doi.org/10.4314/njt.v40i1.5

In recent years, there has been an increasing interest in the study of lightweight syntactic foams (SFs) because of their tailorable properties, quality characteristics and suitable applications in diverse technology industry. A considerable amount of literature has been published on SFs with most of these studies focusing on particular aspect like the matrices types (polymer, metal, ceramics, bio and hybrids); filler types (microparticles/microballoons/microspheres); nanoadditives types (nanotubes, nanofibers, nanoparticles); types of production techniques (powder metallurgy, infiltration and casting, mechanical molding and chemical deposition); and industry applications (aerospace, marine, building and construction, automotive and electrical and electronics). However, much of the literatures up to now has been research articles and few review articles. And there has been no attempt to comprehensively discuss SFs touching on the main research interest in a robust manner. Thus far, this study, brings a comprehensive insight toward the isolated research areas in SFs and then, compares and summarizes outcomes and inference from previous and current studies. And recommends on future research.

The study examined municipal solid wastes characteristics of Gosa dumpsite at Abuja, Nigeria. Waste characterization has not yet been given adequate attention in management of waste in Nigeria and it is a major problem that affects waste materials handling and recovery processes. Wastes samples from Gosa waste dump site, Abuja, were randomly collected and subjected to moisture content, composition, density and size distribution determinations according to prescribed standards in literature. The moisture content of the Gosa waste solid was 19.3%. The results of the characterization of the Gosa municipal solid wastes show 34% organic, 10% paper, 28% plastic, 2% glass, 6% metal, 4% fabric, 2% rubber and 14% dust. The average density of glass, metal, plastic, fabric, rubber, paper, organic and dust materials were 0.044 kg/m 3 , 0.045 kg/m 3 , 0.176 kg/m 3 , 0.043 kg/m 3 , 0.042 kg/m 3 , 0.074 kg/m 3 , 0.143 kg/m 3 and 0.098 kg/m 3 , respectively. The size distribution of the Gosa solid waste ranges from 10-28 cm for metals and plastics and 3-13 cm for paper and glass. The rubber had size ranges from 8-23 cm while size ranges of organic was from 3-6 cm. The large presence of organic, plastic, paper and metal wastes at Gosa waste dump site, is an indication that the municipal solid wastes can be sorted, recycled and processed to other useful products, using the characteristics as a guide. Keyword: Characterization, Density, Municipal Solid Waste, Size Distribution, Waste Management

Optimization of process parameters in aluminum bagasse ash reinforced composite was studied using Taguchi L16 standard orthogonal array for the design of experiment, with the weight percentage of bagasse ash, melting temperature, stirring time and stirring speed as the control factors considered and impact and yield strengths as responses. Sixteen experiments were conducted through stir casting rout, impact and tensile tests were concluded on the samples. Analysis of variance (ANOVA) and the signal to noise ratio were analyzed using the results of the tests. The analysis of variance and main effect plot show that the weight of bagasse is the most critical and contribute over 82% to the impact strength and over 96% to the yield strength. The signal to noise ratio provided the optimal parameters as 5% weight of bagasse, 730oC melting temperature, 2.5 minutes stirring time and 450 rpm stirring speed on the impact strength. The yield strength optimality according to Table 7 for the factors are 15% weight of bagasse, 880oC melting temperature, 2 minutes stirring time, and 500 rpm stirring speed. So, the weight of bagasse improves the mechanical properties of the composite, and sample 5 is the toughest of the materials having the highest impact Energy.Keywords- aluminium alloy, bagasse ash, impact energy, optimization, process parameters, yield strength

The bending behavior of single-walled cubic zirconia nanotubes (CZNTs) is studied in this paper based on a three-dimensional finite element analysis with molecular bonds modeled as structural beam elements and positioned at the joints of beams as substitute of atoms. In order to simulate the bending effect of CZNTs, the free-end is exposed to varying transverse displacements and the maximum force along the cross section at the fixed end is recorded to estimate the bending elastic modulus. The result obtained indicates that the bending elastic modulus of CZNTs depends on chirality and magnitude of applied transverse displacement. The simulated bending modulus of CZNTs fluctuates with the optimum value obtained from the zigzag configuration when 0.5 – 1.0 nm transverse displacement was applied. The results follows similar trend with what was obtained in other studies for carbon nanotubes but at comparatively lesser magnitude.

In Malaysia Small and Medium Enterprises (SMEs) are a significant part of the nation wealth creation and economic. In Malaysia, majority of established businesses are small and medium enterprises with high employment share. The Malaysian government is definite that the framework of the economic transformation plan can raise the small and medium enterprises in developing countries. Therefore, the objective of this study is to thoroughly exploring the predictor which encourages the market orientation practice from the entrepreneurial attitude orientation perspective of the Malaysian entrepreneurs. The contributors of this study are focused on the knowledge body on market orientation to better comprehending of the specific factors that are crucial for business such as small and medium enterprises to help in the country wealth creation.

The structural, mechanical and thermodynamics properties of cubic zirconium oxide (cZrO2) were investigated in this study using ab initio or first-principles calculations. Density functional theory was used to optimize the crystal structure of cZrO2 and thereafter, simulations were conducted to predict the lattice parameters and elastic constants. The Zr-O bond distance was calculated as 2.1763 &#197 with unit cell density of 6.4179 g/cm3. The data obtained were used to determine Young’s modulus, bulk modulus, Poisson’s ratio and hardness of cZrO2 as 545.12 GPa, 136.464 GPa, 0.1898 and 12.663(Hv) respectively. The result indicates that cZrO2 is mechanically stable with thermodynamics properties of a refractory material having potential for structural and catalytic applications in various forms as a nanomaterial.

Zirconia in the form of nanotubes has potential for application in various areas. However, information on structural and mechanical properties of zirconia nanotubes is not easily available and/ or limited in scope. This challenge requires multi-scale numerical modeling and simulation. As a way out, the structure of (10, 10) zirconia nanotube is modeled using available crystal and molecular software (Material Studio&copy and CrystalMaker&copy). The output in the form of PDB file is exported into ANSYS by using a script developed in Python. The output contains only the atomic coordinates and connectivity pattern, which make the conversion process faster and more efficient compared to manual option used when performing similar task.

Analysis of structural and mechanical properties of cubic zirconia was conducted using a simulation code (GULP) that is based on the concept of energy minimization. Some mechanical properties of zirconia were computed such as elastic constant tensors, shear modulus, bulk modulus, Youngs modulus and others along the lattice planes. The stiffness constants obtained (C11, C22 and C33) were equal, implying that zirconia is flexible in all directions of the lattice plane. The predicted bulk modulus was 285 GPa with the shear modulus ranging between 78 and 105 GPa. The Youngs modulus of 577 GPa indicates higher ductile behavior as confirmed by the compressibility of 0.0035. The Poissons ratio with values ranging from 0.16 to 0.31 may indicate high anisotropy. Other acoustic features related to mechanical properties of zirconia such as velocity wave ratio, stress matrix dielectric constants and others were also analyzed. All estimations obtained show good agreement to recent measured properties of zirconia.

Molecular modelling methods were used to investigate the structural and interatomic potential of bulk cubic zirconia. To widen the scope of the expected outcome, GULP and CASTEP software were used based on the concept of minimizing the energy of the crystal structure with respect to atomic coordinates. The crystal structure of cubic zirconia was modelled and optimized; the lattice parameter of 5.10 Å obtained is similar to available calculated and experimental values. The developed interatomic potential is based on Born model for ionic solids without defects. The calculated interatomic potential of 109.67eV per atom is also within acceptable range, but variation was observed depending on the relative position of individual atoms. The modelling gave a better understanding of the bulk crystal structure of cubic zirconia due to detailed parameters that were obtained. Also, the determined parameters were used to estimate the Young’s Modulusof bulk zirconia as 397GPa.

Study of the guided waves in piezoelectric cylinders based on a semi-analytical finite element method is presented. In the study, the dispersion equation was formulated as a generalized eigenvalue problem by treating mechanical displacements and electric potential with one dimensional quadratic finite element model through the thickness of the cylinder. Here the general eigenvalue problem is depended on three parameters, namely, the frequency, the axial wave number and the circumferential wave. A non-integer circumferential wave is introduced here for studying the guided spiral wave. A wave spectrum surface is generated to incorporate the guided spiral waves. Cylinders having different geometry and electric boundary conditions are studied but only the results for a thin cylinder with closed electric boundary conditions are presented.

There is a large variation of mechanical properties, such as Young’s moduli for nanotubes as indicated from both experimental and theoretical studies. From an early study [1], the experimental values of Young’s modulus of the carbon nanotubes was 1.3 −0.4/+0.6 TPa. While, in another study [2] measured value for Young’s modulus of nanotubes as 0.816 ± 0.41 TPa. The wide variation in the experimental results may be due to the several factors including (i) presence of defects in nanotube specimens and (ii) inherent limitations of current experimental techniques.

From proven chemical calculations [1], the harmonic functions provide a reasonable approximation to the potential energy of molecular systems in which the bond length is near its equilibrium position.

Nanocomposite is a multiphase solid material where one of the phases has one, two or three dimensions of less than 100 nm, or structures having nano-scale repeat distances between the different phases that make up the material. In the broadest sense this definition can include porous media, colloids, gels and copolymers, but is more usually taken to mean the solid combination of a bulk matrix and nano-dimensional phase(s) differing in properties due to dissimilarities in structure and chemistry. The mechanical, electrical, thermal, optical, electrochemical, catalytic properties of the nanocomposite will differ markedly from that of the component materials [1–3].

There are two types of nanotubes: single-walled nanotubes (SWCNTs) and multiwalled nanotubes (MWCNTs), which differ in the arrangement of their graphene cylinders. SWCNTs have only one single layer of graphene cylinders; while MWCNTs have many layers (approximately 2–50).