Rice husk

The kinetic and thermodynamic efficacy of Irvinga Gabonensis plant extract as an effective eco-friendly inhibitor for mild steel in acidic environment were studied using gravimetric measurement at varied temperature of 298, 308, and 318 K, as well as scanning electron microscopy surface characterization, and were utilized. The findings indicate that Irvinga Gabonensis leaf extract inhibited acid-induced corrosion of MS effectively. The results of the kinetic analysis indicated that the inhibited species were more resilient.

This study is aimed primarily to investigate the influence of layup configuration on ballistic resistance of glass fibre reinforced polymer (GFRP) using finite element analysis (FEA). Although, numerical simulation has been used to improve on the ballistic resistance of composite materials for combat helmet applications. However, not many FEA works have considered linear static analysis of different layup configurations of GFRP composites ballistic resistance for combat helmet. Four different layup configurations T_1, T_2, T_3 and T_4 of Glass Fibre Reinforced Plastic laminate for combat helmet were investigated in this study. The FEA result showed that all the tested configurations based on NIJ-0106.01 standard using 9 mm, 8g Full Metal Jacket (FMJ) bullet at a velocity of 358 m/s ±15 were well within the failure surface of the failure criterion. The ply failure indices of 0.1520, 0.1510,0.1480 and 0.137 for T_1, T_2, T_3 and T_4 respectively were quite within the failure envelope. Hence, they are failure safe most especially within the test region. In addition, numerical simulation showed that T_3 has better ballistic resistance among the lot.

BFS blast furnace slag presentation of the challenges and opportunities is related to the use as a substitute of Portland cement, respectively of natural sand in the composition of road cement concretes. The inclusion of BFS in the composition of road concrete is an ecological approach from the point of view of reducing the consumption of non-renewable materials. A rational design of road concrete composition requires knowledge of the physical-mechanical properties of BSF with favorable and unfavorable impact on the durability of road concrete. Aspects of the impact of the quality of GGBS granulated and ground blast furnace slag as well as the properties of ACBFS air-cooled blast furnace slag crushed aggregates were analyzed in this article. Although all the physical-mechanical properties books are suitable for the slag powders inclusion in the road concretes composition, the high content of CaO-free and C3A limits the substitution of cement with GGBS to prevent the occurrence of degradation during the exploitation period. ACBFS aggregates have been proven to be non-reactive to alkalis in cement, thus being suitable for inclusion in road cement concrete compositions. The increased values of the water absorption coefficient, respectively of the fineness modulus of the ACBFS type aggregates compared to natural sand, the reduction of the workability of the road concrete and the increase of the water/binder ratio. Finally, for the design of road concrete compositions with slag, preliminary tests were carried out on three series of mixtures, in which Portland cement was replaced by 15% GGBS and natural sand by 25% and 50% ACBFS respectively. The optimal slag road concrete recipe was established based in: increased workability (an important characteristic of road concretes), a low water/binder ratio and a 7-day compressive strength close to the control sample.

The paper proposes a new equation for the prediction of punching shear strength of reinforced concrete flat slabs. The basis of the new predictive equation is a detailed numerical parametric study conducted using the nonlinear 3D finite element analysis using FE software MASA. For this, results of the previously tested flat slabs from literature are used as reference for validation of the numerical model. The numerical modelling procedure is validated with two previously tested slabs, one failing in pure punching prior to yielding of flexural rebar, and the second failing in flexure-punching which resulted in yielding followed by punching. The result shows that the load-displacement behavior, failure modes and the crack pattern are captured well by the analysis. Following the validation, a detailed parametric study is performed to investigate the influence of slab depth, concrete strength, longitudinal reinforcement ratio, column size and effect of reinforcement spacing. From the evaluation of results, it is observed that the punching resistance increases with slab depth but at a decreasing rate (size effect). The punching shear strength also increases with increasing longitudinal reinforcement ratio, concrete strength as well as the column area. All the reinforcing bars placed within a distance of 3.5 times the effective depth of the slab from the column center contributes significantly towards dowel action. With increasing column size, the deformation at the peak load also increases. Based on the evaluation of the results of the analyses, an empirical equation for the prediction of punching shear is derived. The results of the equation are compared with the results of a large experimental database of 235 tests, and it is shown that the proposed equation leads to better agreement with the test results compared to the equations given in the current codes (ACI, Canadian, Eurocode, Japanese code). The comparison shows that generally the predictions by existing equations in the codes tend to be unconservative for large slab with low reinforcement ratio.

Qualitative, descriptive and evaluative data were collected for analysis. Material compositional information was assessed with the use of Proton-induced X-Ray Emission (PIXE) technique; PIXE result returned twenty-three (23) elements that are used as chemical fingerprints for the selected pottery objects. Major, minor and trace elements discovered were expressed in parts per million (ppm). The study concluded that the data similarities, differences, and correlation provided enhanced provenance data generation useful in taxonomic and provenance determination of potteries with the possibility of generating a database to identify Yoruba ceramic objects generally.