Modelling Water Absorption Index and Compressive Strength of Paving Stone Composites with Polyethylene Terephthalate (PET) as Total Binder Replacement

Polyethylene terephthalate (PET) wastes were melted and mixed with river sand to produce paving stone composites (PSCs) of mix ratio 1:3, labelled (PET: 10, 20, 30, 40, and 50%); and sand-cement mix of 1:3 labelled PET 0% (control). In a mold measuring 50 × 100 × 200mm, three replicates of PSCs of each mix ratio and control, were produced and cured in water at a room temperature of (27 ± 2ºC) for 28 days. The PSCs showed a better water absorption property as it ranges from 6.98 % to 3.59 % as against 11.11 % for the control. Significant compressive strengths were shown by the PSCs; PET 30% had the highest mean value of 20.59 N/mm2, while the control had the lowest mean value of 8.63 N/mm2. Using Design Expert tool in analyzing the laboratory data obtained for both water absorption index and compressive strength, the results show that the developed quadratic model for water absorption index (WAI) has an adjusted and predicted coefficient of regressions of 0.9851 and 0.9821 respectively, with an average precision of 98.62% within the research work, allowing for simulation of WAI outcomes at different PET contents. Also, the compressive strength model is a quadratic, with adjusted and predicted coefficients of regressions of 0.9623 and 0.9526 respectively, and shows reduced variation between actual and predicted values, making it useful for design space navigation. The research suggests that utilizing PET waste as a complete binder replacement in paver production is a cost-effective method for managing wast

Reference luminal diameters of the carotid arteries among healthy Nigerian adults

Background: The carotid arteries serve as major blood supply to the head and neck region of the body. Understanding their structure and function in the pathogenesis of stroke and in interventional neuroradiology due to luminal stenosis, atherosclerosis and wall stiffness is paramount. Doppler ultrasound scan plays key role in the early diagnosis of the pathologies of the arteries as it is an affordable, accessible, reliable and non-invasive clinical tool. Knowing normal average diameter of the carotid arteries among healthy individuals is important in making correct clinical diagnosis in any population. The aim of the study was to determine mean diameters of the carotid arteries among healthy adult Nigerians for reference. Materials and methods: Prospectively studied 104 healthy Nigerians within the ages of 18 and 65 years by taking doppler scans of their carotid arteries (common, internal and external) on both sides and measured each diameter. Using a 95% confident level, P-value of < 0.05 was significant. Results: Of the studied population, 62 were males and 42 were females, and the average age of the subjects was 28.32 ± 9.09 years. From this study, the average luminal diameter of the common carotid artery = 0.61 ± 0.08 cm, internal carotid artery = 0.60 ± 0.08 cm and external carotid artery = 0.49 ± 0.10 cm. The results showed that although, there are differences in measurements between the two sexes (males slightly higher than females in CCA) and between right and left sides (with right side slightly higher), they are not statistically significant. Conclusions: This sonographic study on healthy Nigerian adults has given us normal reference values of the luminal diameters of the carotid arteries among Nigerians, which clinicians can make reference to, when assessing carotid artery diameters of patients in Nigeria