Our research focuses on examining the characteristics of thin accretion disks encircling rotating regular black holes. In this study, we investigate the important features of accretion disks surrounding Bardeen's regular black holes, which play a crucial role in addressing the singularity issue. The horizon configuration of rotating Bardeen black holes is analyzed in details, as well as the innermost stable circular orbits related to this spacetime. The primary goal is to derive quantitively the radiative flux, differential and spectral luminosities of the accretion disk. Within the specified gravitational field, particularly, by taking the parameter r_0*>0 and fixing the j=0.2, our findings show that the corresponding accretion disk’s luminosity exceeds that one predicted by the Kerr metric at identical value of spin parameter ( j=0.2). Making the juxtaposition of Bardeen’s black hole parameter with the spin parameter of the Kerr black hole we reveal that the spacetime corresponding to the non-rotating Bardeen black holes, in some certain cases, can imitate the Kerr spacetime.
Division remains one of the most computationally demanding operations in digital arithmetic. Traditional algorithms, such as restoring, non-restoring, and SRT (Sweeney–Robertson–Tocher) division, are limited by sequential dependencies that reduce throughput in hardware implementations. To overcome these constraints, this work proposes a pipelined integer divider architecture that employs precomputed divisor multiples and comparator-based logic to eliminate the need for full binary adders in the quotient selection stages. The proposed design consists of a three-stage pipeline, where each stage compares the shifted partial remainder with stored multiples of the divisor (B, 2B, 3B) to generate two quotient bits per clock cycle. This approach achieves a 2× reduction in the number of computation stages compared with conventional radix-2 dividers and ensures continuous operation after an initial pipeline latency. The architecture was described in Verilog hardware description language (HDL) and implemented on a Xilinx Artix-7 (XC7A100T-1CSG324C) field-programmable gate array (FPGA) using the Xilinx ISE Design Suite 14.4. Post-synthesis simulation confirmed correct quotient and remainder generation with a maximum operating frequency of 208 MHz. The implementation occupied less than 0.3% the look-up table (LUT) resources, achieving over a twofold performance improvement compared with a non-pipelined baseline. These results demonstrate that the proposed divider provides an efficient trade-off between speed and hardware cost, making it suitable for digital signal processing and embedded computation systems.
1 December 2023 in Physical Sciences and Technology
The distribution of dark matter in the low surface brightness spiral galaxies U5750, U11454, U11819, and U11648 is analyzed by utilizing well-established density profiles from existing literature. These profiles include the Beta, Brownstein, Burkert, exponential sphere, pseudo-isothermal, and Persic profiles. For simplicity, we assume spherically symmetric distribution of dark matter in the considered galaxies, without accounting for their intricate structural complexities. For each density profile, we fit the rotation curve data to the aforementioned galaxies. Employing Markov Chain Monte Carlo statistical analyses, we infer model-free parameters from the rotation curves, namely the characteristic (central) density and scale radius. This enables us to estimate the total dark matter mass within the galactic halos. To identify the best-fit profile, we employ the Bayesian Information Criterion. Additionally, we adopt the Levenberg-Marquardt nonlinear least squares approach for the purpose of comparison and completeness. Through our statistical analysis, we offer a physical interpretation behind the selection of specific profiles. This interpretation is based on the insights obtained from the analyses.