Abstract Within the framework of Einstein-Maxwell theory geometric properties charged rotating discs dust, using a post-Newtonian expansion up to tenth order, are discussed. Investigating disc’s proper radius and circumference allows us address questions related Ehrenfest paradox. In Newtonian limit there is an agreement with disc from special relativity. The dust also possesses material-like p...

In this article, we introduce a computational methodology for golf disc shape optimization that employs novel parameterization by cubic B-splines. Through application of batch Computational Fluid Dynamics simulations and Machine Learning, the yields functional relationships—so-called surrogate models—between flying rotating its flight characteristics. The models facilitate free constrained in b...

The magneto-rotational instability (MRI) is the most likely mechanism for transportation of angular momentum and dissipation energy within hot, ionized accretion discs. This produced through interactions a differentially rotating plasma with an embedded magnetic field. Like all substances in nature, disc has potential to become magnetically polarized when it interacts In this paper, we study ef...

Biological treatment using attached growth in a threestage labscale rotating biological contactor (RBC) was implemented for wastewater from dairy industries. The wastewater contained high level of organic compounds due to cleaning and filling processes. Nutrients available in the wastewater enhanced the growth of microorganisms and allowed the biological treatment to be effective. The RBC consi...

Passive kinematic synchronization enables two dynamic physical systems to generate the same motion without any physical interaction or mediating control laws. In this paper, we demonstrate a generalized kinematic matching technique to model and passively synchronize two physically dissimilar and uncoupled rotating systems. The method is demonstrated by matching the motion of systems with differ...

The spin-down of Be stars due to angular momentum transport from star to disc has been considered. This has been prompted by empirical studies of observed optical and IR line profile studies indicating that the disc is rotating in a Keplerian fashion. It is found that substantial spin-down may occur, especially for late B stars throughout their main-sequence lives for the “strongest” discs (mos...

Wastewater from wine-related industries is characterised by high variability in COD and pH. Disposal of these effluents with little or no treatment could lead to heavy financial penalties or pollution of soil and water resources. A pilot-scale rotating biological contactor (RBC) was evaluated for the treatment of winery effluent, with specific focus on the biofilms that formed on the RBC discs....

In rotating biological contactors (RBC), the oxygen mass transfer coefficient (KLa) is often inadequately predicted by the available models. Hence, dimensional analysis based empirical models were developed for predicting KLa and the component of KLa due to turbulence (KLat) using data available in the literature. The overall oxygen transfer number (OTN) and its component due to turbulence (OTN...