Indexing

Abstract: Traffic congestion is a persistent challenge in urban transport systems, particularly around roundabouts where nonlinear merging and circulating flows create instability and delays. Traditional microscopic, mesoscopic, and macroscopic models often neglect explicit treatment of priority rules, capacity drops, and queue spillback, limiting their ability to predict roundabout-induced congestion. To address this gap, this study develops a coupled Navier–Stokes–advection–diffusion framework for simulating traffic dynamics at roundabouts. The governing equations are discretized using the finite volume method with a QUICK scheme for spatial accuracy and advanced in time with a Crank–Nicolson integration for stability. Non-dimensionalization ensures general applicability across different traffic environments. Simulation results reproduce fundamental traffic relations, identify optimal densities for maximum throughput, and reveal oscillatory stop-and-go waves consistent with empirical observations. Scenario analysis shows that increased diffusion enhances stability but reduces flow capacity, capturing real-world trade-offs between efficiency and control. The study concludes that embedding yield laws and circulating feedback into continuum equations provides a rigorous foundation for analyzing roundabout performance. Policy recommendations include adopting geometry- and flow-calibrated entry controls, while future research should incorporate stochastic demand and adaptive control strategies to refine predictive accuracy. This contribution provides both theoretical innovation and practical insights for sustainable traffic management.

Keywords: Advection–diffusion modelling; Congestion management; Navier–Stokes equations; PDE-based simulation; Roundabout performance; Traffic flow dynamics.

Title: Mathematical Modelling of Traffic Flow Dynamics Around Roundabouts Using Navier–Stokes and Advection–Diffusion Equations

Author: Momanyi Mogire Krifix, Shichikha Maremwa, Kandie Joseph, Lucy Jerop Ngetich

International Journal of Recent Research in Interdisciplinary Sciences (IJRRIS)

ISSN 2350-1049

Vol. 12, Issue 3, July 2025 - September 2025

Page No: 18-27

Paper Publications

Website: www.paperpublications.org

Published Date: 29-September-2025

Abstract: This paper examines the pivotal responsibilities of laboratory administrators and the transformative impact of automation and artificial intelligence (AI) on diagnostic methodologies. Drawing from recognized managerial principles, it outlines essential administrative functions such as planning, staffing, organizing, leadership, and control. The discussion emphasizes the growing adoption of AI and automation in laboratory medicine, spotlighting their potential to boost productivity, enhance precision, and improve healthcare outcomes. Nevertheless, it also addresses notable challenges including workforce displacement, ethical dilemmas, and excessive dependence on algorithms. Special attention is given to the Nigerian context, where issues like insufficient funding, obsolete infrastructure, and lack of adequate training slow technological progress. The paper concludes by recommending targeted investments, ongoing professional development, and regulatory frameworks to ensure technology complements rather than compromises the role of laboratory administrators in Nigeria.

Keywords: Administration, Artificial Intelligence, Role and Automation.

Title: A REVIEW: THE ROLE OF AUTOMATION AND ARTIFICIAL INTELLIGENCE IN ADMINISTRATION

Author: Okpaka, Confidence Ogechi, Onyeozu, Chijioke Kenneth, John, Godson Nnamdi

International Journal of Recent Research in Interdisciplinary Sciences (IJRRIS)

ISSN 2350-1049

Vol. 12, Issue 3, July 2025 - September 2025

Page No: 11-17

Paper Publications

Website: www.paperpublications.org

Published Date: 22-September-2025

Abstract: The acute toxicity of aqueous fruit extract of Annona muricata was evaluated in Swiss albino rats. The rats were randomly distributed into four groups of three animals each for the first phase. The groups were respectively administered orally aqueous fruit extract of Annona muricata at 0, 10, 100, and 1000 mg/kg body weight in a single dose. In the second phase of the experiment, the albino rats were divided into four groups of 3 animals each and were orally administered single doses of the extract at 0, 1600, 2900, and 5000mg/kg body weight and monitored frequently for 24 hours and 14 days. No death was recorded in each group. After the oral intubation, no mortality was observed in the albino rats. All the animals showed a positive gain in body weight throughout the study. The oral LD₅₀ of aqueous fruit extract of Annona muricata was estimated to be equal to or below 5000mg/kg body weight, and the plant extract was concluded to be safe and non-toxic when taken through the oral route. The LD₅₀ value, defined as the statistically derived dose that, when administered in an acute toxicity test, is expected to cause death in 50% of the treated animals in a given period, is currently the basis for toxicologic classification of chemicals.

Keywords: Oral Acute Toxicity, Annona muricata, Aqueous Fruit Extract, Albino Rats.

Title: ORAL ACUTE TOXICITY STUDIES OF THE AQUEOUS FRUIT EXTRACT OF ANNONA MURICATA IN ALBINO RATS

Author: AMARACHI M. ACHEBE, ALOYSIUS C. ENE, BLEESING A. MONDAY, FORGIVE C. EGEGBULA, MAUREEN O. ARINZE

International Journal of Recent Research in Interdisciplinary Sciences (IJRRIS)

ISSN 2350-1049

Vol. 12, Issue 3, July 2025 - September 2025

Page No: 1-10

Paper Publications

Website: www.paperpublications.org

Published Date: 08-September-2025