A fully relativistic lattice Boltzmann algorithm

Starting from the Maxwell-Juettner equilibrium distribution, we develop a relativistic lattice Boltzmann (LB) algorithm capable of handling ultrarelativistic systems with flat, but expanding, spacetimes. The algorithm is validated through simulations of quark-gluon plasma, yielding excellent agreement with hydrodynamic simulations. The present scheme opens the possibility of transferring the recognized computational advantages of lattice kinetic theory to the context of both weakly and ultra-relativistic systems.Comment: 12 pages, 8 figure

A Proposed Quality Assurance Intelligent Model for Higher Education Institutions in Saudi Arabia

Recent growth and demands for dealing with increasing complexity in management, evaluation, and accreditation of higher educational institutions have led keynote academic institutions and higher education authorities to adopt and try nonconventional solutions known to business firms to account for massive data management. The development in new practices and merging technology for analytics and information management have offered different solutions such as data warehousing, big data, and business intelligence. Such solutions are gradually being installed in a number of renown universities. Due to the difference between the two firms (higher education and business industry) in nature and aims, tailor-made solutions are needed. This paper shares authors' experience in designing and implementing an educational information system in the College of Computers and Information systems at King Saud University, Saudi Arabia. The paper also highlights differences between educational intelligence and business intelligence systems. Higher education implementation aspects ensuring suitable data query service to ease the running of high educational institutions are discussed and recognized

Wall Orientation and Shear Stress in the Lattice Boltzmann Model

The wall shear stress is a quantity of profound importance for clinical diagnosis of artery diseases. The lattice Boltzmann is an easily parallelizable numerical method of solving the flow problems, but it suffers from errors of the velocity field near the boundaries which leads to errors in the wall shear stress and normal vectors computed from the velocity. In this work we present a simple formula to calculate the wall shear stress in the lattice Boltzmann model and propose to compute wall normals, which are necessary to compute the wall shear stress, by taking the weighted mean over boundary facets lying in a vicinity of a wall element. We carry out several tests and observe an increase of accuracy of computed normal vectors over other methods in two and three dimensions. Using the scheme we compute the wall shear stress in an inclined and bent channel fluid flow and show a minor influence of the normal on the numerical error, implying that that the main error arises due to a corrupted velocity field near the staircase boundary. Finally, we calculate the wall shear stress in the human abdominal aorta in steady conditions using our method and compare the results with a standard finite volume solver and experimental data available in the literature. Applications of our ideas in a simplified protocol for data preprocessing in medical applications are discussed.Comment: 9 pages, 11 figure

Ocean Acidification around the UK and Ireland

The average atmospheric carbon dioxide (CO2) concentration exceeded 414 parts per million (ppm) in 2021, a 49 % increase above pre-industrial levels, and increasing on average by 2.4 ppm per year over the past decade (Friedlingstein et al., 2022). This ongoing increase is primarily due to CO2 release by fossil fuel combustion, cement production and land-use change (mainly deforestation) (Friedlingstein et al., 2022; IPCC, 2021). Over a quarter of this annual anthropogenic CO2 emission dissolves into the Earth’s oceans each year (fossil fuel CO2 emissions = 9.5 ± 0.5 gigatonnes of carbon per year (Gt C yr-1, 1 Gt = one thousand million tonnes)), Land-use change emissions = 1.1 ± 0.7 Gt C yr-1, ocean uptake = 2.8 ± 0.4 Gt C yr-1; Friedlingstein et al., 2022). Once dissolved, the CO2 no longer influences the atmospheric heat budget, so this oceanic uptake mitigates human-driven warming and climate change. However, dissolved (or aqueous) CO2 undergoes a chemical reaction that releases hydrogen ions (H+), thereby decreasing the seawater’s pH (Figure 1). As pH declines, the carbonate ion concentration ([CO32−] also declines (Figure 1). The [CO32−] controls the saturation state (Ω) of calcium carbonate (CaCO3) minerals such as aragonite (ΩArag) and calcite (ΩCal), and indicates the ability of these minerals to precipitate (form) or dissolve. At Ω >1 water is supersaturated with Ca2+ and CO32− ions allowing CaCO3 minerals to form. When Ω <1, seawater is undersaturated with Ca2+ and CO32− ions and therefore any exposed CaCO3 minerals are prone to dissolution. These collective changes in marine carbonate chemistry are known as ‘ocean acidification’

Simulation Of A Systolic Cycle In A Realistic Artery With The Lattice Boltzmann Bgk Method

Introduction Recently, we have investigated the accuracy of the LBGK model in recovering analytical Womersley solutions for oscillatory two dimensional channel flow and three dimensional tube flow, covering a range of Womersley and Reynolds numbers. We demonstrated that LBGK is accurate enough to simulate time-dependent fluid flows, such as blood flow in arteries. 1 As a next step, the D3Q19 quasi incompressible LBGK model is used to simulate systolic flow in a rigid tube and in a model of the human abdominal aorta. 2. Simulations 2.1. Systolic flow in a tube The main objective for this benchmark is to test the accuracy of the simple bounceback rule against a curved boundary condition recently proposed by Bouzidi et al. Although it is known that the bounce-back rule is first order accurate while most curved boundary conditions are claimed to be of second order, the bounce-back rule is still more attractive for its simplicity and exact mass conservation. We test the errors ass