A comparative analysis of the chemical composition and compliance level to established standards of concrete reinforcement steel rods rolled in Nigeria.

Nigeria is presently facing the challenges of collapsing buildings and bridges due to substandard materials used as reinforcement products. The increasing use of scraps as feedstock for the production of reinforcing steel bars by steel rolling mill companies has adversely affected the quality of rebars in Nigeria. This research study aimed to appraise the chemical properties of selected brands of steel rebars of Nigeria. Thirty selected brands of rebars were sourced from the six geopolitical zones in Nigeria, and their chemical compositions were analysed for level of compliance with five selected standards (SON, BSI, ASTM, AISI, ISO). The chemical composition test was performed using Optical Light Spectrometric methods. One way analysis of variance (ANOVA) test was performed using SPSS version 20 to examine whether significant differences exist or not in mean chemical composition for the different categories of selected steel rods. Statistical analysis shows a significant difference (P < 0.05) in chemical composition and compliance level between the different types of selected steel rods. The imported steel rods recorded the highest mean (µ = 101.4) in terms of chemical composition and compliance, followed by locally rolled from imported billets (µ = 101.2), TMT steel rods (µ = 101.0), and ordinary steel rods (µ = 100.6). Concerning CEV1 and CEV2, it was observed that all the brands were fully compliant within the maximum permissible ranges given in the local, foreign and international standards except an ordinary steel bar of Brand 16, which has value beyond the specified limits of CEV1. This study also shows that all imported and 77.8% of locally-rolled steel bars are low-carbon steel as specified by the selected standards.

Mathematical models for thermionic emission current density of graphene emitter.

In this study, five mathematical models were fitted in the absence of space charge with experimental data to find a more appropriate model and predict the emission current density of the graphene-based thermionic energy converter accurately. Modified Richardson Dushman model (MRDE) shows that TEC's electron emission depends on temperature, Fermi energy, work function, and coefficient of thermal expansion. Lowest Least square value of [Formula: see text] makes MRDE most suitable in modelling the emission current density of the graphene-based TEC over the other four tested models. The developed MRDE can be adopted in predicting the current emission density of two-dimensional materials and also future graphene-based TEC response.

Dataset on physical properties of raw and roasted cashew nuts.

Cashew nut is one of the topmost edible crops in the world. However, one of the challenges of this crop is processing. Designing an equipment for the processing of cashew nut requires the knowledge of its physical properties data. The dataset in this article contained the physical properties of raw and roasted cashew nuts. The physical properties include length, width, thickness, geometric mean diameter, sphericity, true density, bulk density, porosity and mass of cashew nut. Two experiments were performed. In one experiment, raw cashew nut was roasted in groundnut oil. In the second experiment, raw cashew nut was roasted in palm-kernel oil. The physical properties of the nuts were measured before and after roasting in hot oil. The data were subjected to a paired sample t-test analysis to determine the level of significant difference. The data of the cashew nut graded with machine and sorted with hand manually were compared. The data provided in this article will be useful in designing various types of equipment for grading, separating and cleaning cashew nut. It will also be useful in the design of storage structures and processing machines.

Comprehensive data on the mechanical properties and biodegradation profile of polylactide composites developed for hard tissue repairs.

Polylactide (PLA), a biopolymer, was reinforced with three fillers (two organic reinforcements and one inorganic filler). The processing technique used to fabricate the composites was the melt-blending technique. The composites and the unreinforced PLA were subjected to microhardness, compression and biodegradation characterisations. Data obtained are presented in this article as raw data. Data from microhardness and compression tests were used to predict the fracture toughness. The biodegradation of the composites was also examined, and the data obtained reported in this article. The data presented in this article allow for a comprehensive understanding of the mechanical behaviour and the biodegradation profile of three composites of PLA with respect to their applications as biodegradable implants. It also helps in the selection of fillers for biopolymers such as PLA.