arXiv subjects

Muhammad Yusuf

Publications and source records attributed to Muhammad Yusuf.

3 recordsLinked to original sources

arXiv2026

NGC 6134: a comprehensive study through photometric and kinematic analysis using Gaia DR3

Open clusters provide a unique laboratory for precisely constraining stellar age, distance, and metallicity, facilitating studies on exoplanet-host star correlations. Building on our previous membership study, we analyze photometric data to comprehensively characterize the open cluster NGC 6134 by determining its fundamental parameters, 3D spatial distribution, substructures, and mass segregation. Using the ASteCA code, we derive the cluster's parameters: $\mathrm{[Fe/H]} = 0.08 \pm 0.06$, $\log(t) = 9.14 \pm 0.01$, $d = 1064.43 \pm 15.19$ pc, and $A_\mathrm{v} = 1.03 \pm 0.05$ mag. Independent Bayesian inference of individual member distances yields a cluster distance of $1070.83 \pm 2.50$ pc, in excellent agreement with the ASteCA results. Spatial substructures are successfully mapped using Gaussian Mixture Models, revealing a three-component distribution corresponding to the cluster's core, tidal tail, and halo. Furthermore, Minimum Spanning Tree analysis indicates that the observed mass segregation is driven by dynamical evolution rather than primordial origins. Finally, our analysis of the cluster's Color--Magnitude Diagram identifies probable blue straggler stars and a main-sequence gap, which we conclude is strongly linked to the cluster's binary fraction.

astro-ph.GA↗

arXiv2020

Fines Migration and Permeability Decline during Reservoir Depletion Coupled with Clay Swelling due to Low-Salinity Water Injection: An Analytical Study

Fines migration behavior can either promote or obstruct fluid flow within the reservoir and is crucial for productivity optimization that needs fundamental understanding. The present work focuses on the contributions from effective stress build-up due to reservoir depletion and decreases in brine salinity from low-salinity water injection. Particle detachment is studied analytically by using the critical retention concentration function modified with stress and salinity dependents. Increase in formation effective stress leads to deformations within the reservoir configurations due to micro-cracks and reduced pore dimensions. Decreased size of the travelling channels promotes particle detachment, while the critical retention concentration decreases. A sensitivity study reveals that, under influence of effective stress, particle size and fluid velocity are dominant parameters controlling the fines migration by influencing the particle detaching forces. With decreasing brine salinity (e.g. via low-salinity water injection), clay particles that are attached on the pore surface increasingly swell, leading to reduction in effective pore space and flow channel. Decreased pore space directly obstructs travelling of suspended particles and fluids which results in permeability decline. Initial clay particle size is found to be a critical factor controlling particle detachment behavior. Small initial particle sizes are not likely to detach from the pore surface as a result of weak detaching forces, hence the analysis finds the critical retention concentration unchanged resulting in negligible permeability decline as a function of brine salinity. Considering both effects, effective stress and brine salinity, stress-dependent effects dominate salinity-dependent effects at low effective stress while the two contribute equally at high effective stress.

physics.geo-ph↗

arXiv2018

Critical properties of the antiferromagnetic Ising model on rewired square lattices

The effect of randomness on critical behavior is a crucial subject in condensed matter physics due to the the presence of impurity in any real material. We presently probe the critical behaviour of the antiferromagnetic (AF) Ising model on rewired square lattices with random connectivity. An extra link is randomly added to each site of the square lattice to connect the site to one of its next-nearest neighbours, thus having different number of connections (links). Average number of links (ANOL) $\kappa$ is fractional, varied from 2 to 3, where $\kappa = 2$ associated with the native square lattice. The rewired lattices possess abundance of triangular units in which spins are frustrated due to AF interaction. The system is studied by using Monte Carlo method with Replica Exchange algorithm. Some physical quantities of interests were calculated, such as the specific heat, the staggered magnetization and the spin glass order parameter (Edward-Anderson parameter). We investigate the role played by the randomness in affecting the existing phase transition and its interplay with frustration to possibly bring any spin glass (SG) properties. We observed the low temperature magnetic ordered phase (N\'eel phase) preserved up to certain value of $\kappa$ and no indication of SG phase for any value of $\kappa$.

cond-mat.dis-nn↗