University of Azad Jammu & Kashmir

This study investigates the complex dynamics and codimension-two bifurcations in a delayed mutually coupled optoelectronic system. The objective is to analyze the effects of feedback delay and coupling strength on the system dynamics and to provide insights that enhance the reliability and performance of optoelectronic and photonic technologies used in optical communication and signal processing. DDE-BIFTOOL is employed to construct bifurcation diagrams with respect to the feedback delay parameter (τ) and coupling strength parameter (β), enabling the identification of double-Hopf bifurcation points. The method of multiple scales (MMS) is then applied to derive complex amplitude equations near the bifurcation points. Furthermore, the method of normal form is used to classify and unfold the bifurcation behavior and determine the stability characteristics of the resulting solutions. The analysis reveals the existence of several double-Hopf bifurcation points and demonstrates a variety of complex dynamical behaviors. Stable equilibrium states, stable periodic oscillations, and bistability of periodic solutions are identified in specific parameter regions. Additionally, more intricate dynamics, including stable almost-periodic solutions and phase-locked solutions, are observed. The system is shown to transition to chaos through different routes depending on the varying parameter: chaos emerges through a period-5 window when β varies, whereas a period-doubling bifurcation route to chaos is observed when τ varies. This work provides a comprehensive bifurcation analysis of a delayed, mutually coupled optoelectronic system, with an emphasis on codimension-two dynamics and the unfolding of a double-Hopf bifurcation. The results contribute to a deeper understanding of nonlinear behaviors in optoelectronic systems and offer valuable theoretical guidance for the design and optimization of advanced photonic devices and communication systems.

Process capability indices are powerful indices used for evaluating the performance of manufacturing and service processes in delivering outputs within certain bounds. Of all these indices, Cpy and CNpmk are very vital in ascertaining process yield and centering. However, the majority of conventional process capability indices presuppose normality in process data, which is not the case in most real-life processes. The log-logistic distribution, which is famous for its ability to handle skewed and heavy-tailed data, is a better option compared to other non normal processes.These challenges are then overcomed in this study by integrating Cpy and CNpmk with log-logistic distribution. We propose a framework for analysis of process capability under log-logistic distribution employing eight estimators, namely maximum likelihood, ordinary and weighted least square, Anderson-Darling and right tail Anderson-Darling, Cramer-von Mises, and Bayesian estimators using reference and Jeffreys' priors. We developed bootstrap confidence intervals for the aforementioned estimators of process capability indices. Monte Carlo simulations are performed to compare performances of these estimators via mean squared error and width of bootstrap confidence intervals. At the end, two real data sets are discussed for illustration purposes.

The Lumshiwal Formation, of Early Cretaceous age, was studied for its sedimentology, provenance, paleoclimate, tectonic setting, and economic significance using petrography, XRD, and geochemical analysis. It comprises ferruginous glauconitic sandstone and peloidal fossiliferous limestone. The formation’s lower contact with the Chichali Formation is conformable, whereas its upper contact with the Kawagarh Formation is disconformable. The sandstone is classified as subarkose, and its provenance is linked to the craton interior, as evidenced by QmFLt and QtFL ternary diagrams. The paleoclimate during deposition was sub-humid to humid, consistent with a passive continental margin setting of the northern Indian Plate. Sandstone detritus was derived from the Indian Shield, particularly the Nagar Parkar and Aravalli ranges. Geochemical indicators such as Al2O3–CaO–K2O diagrams suggest intense chemical weathering, whereas TiO2 versus Al2O3 plots indicate a mixed basalt–granite source terrain. Economically, the glauconitic clays are significant as potential potassium fertilizers. Additionally, the peloidal limestone contains phosphorite pellets. The Lumshiwal Formation sandstone, with porosity exceeding 10

This study examines club convergence and the deqterminants of club membership for a set of 113 global economies over the period 2012–2022. Using the Phillips and Sul (2007) methodology, the study identifies convergence patterns in food security across countries, forming distinct clubs based on food security levels. In addition, applying an Ordered Logit approach, the study investigates the role of initial conditions in countries’ club formation. The findings reveal seven clubs for overall food security, six for affordability, and five each for availability, quality and safety, and sustainability and adaptation. Regarding the drivers of club formation, differences in initial conditions across countries are shown to significantly shape club membership. Specifically, GDP growth, agricultural value added, livestock production, agricultural water use, and urbanization lower the likelihood of joining the top tier food-security clubs (1 and 2) while increasing the probability of a country to become the part of mid-tier clubs (4, 5 and 6); Club 3 remains unaffected, and the effects on Club 7 are relatively weaker. This pattern aligns with the multiple-equilibria framework of club convergence, wherein heterogeneous initial conditions direct countries toward distinct basins of attraction. Therefore, strengthening the food security infrastructure of low- and middle-income countries is essential to enhance absorptive capacity and accelerate the pace of convergence.

The Pakistan-Iran border region remains underexplored despite its strategic location within the hydrocarbon-rich Middle East. The Middle East holds 50% of proven oil reserves and 40% of world's natural gas reserves in the world. There have been several myths of shared petroleum system between the two countries, without proper geological evidence. However, there has never been a comprehensive discussion of the geological setting and framework. Recently, there has been interest of several oil and gas companies in Pakistan to explore the Makran-Kharan area. This review investigates the geological characteristics and petroleum systems of the transboundary basins between Pakistan and Iran. The study synthesizes existing geological, geophysical, and geochemical data to assess hydrocarbon potential, highlighting key elements such as sedimentary basins, source rocks, reservoir formations, and trapping mechanisms. Although significant petroleum reserves are concentrated in western Iran, the southeastern region near the Pakistan border exhibits minimal exploration and discoveries. Key basins, include the Makran Offshore Basin, Kharan Forearc Basin, and Jaz Murian-Mashkel Forearc Basin. Furthermore, these basins show promising indicators such as oil seeps, structural traps, and seismic anomalies. This paper calls for increased collaboration between Pakistan and Iran, enhanced exploration efforts, and further geophysical surveys to unlock potential reserves. This will not only boast exploration efforts in Eastern Iran and Western Pakistan but also bring a positive changes in their economies. This study will be a landmark in understanding the sedimentary basins of the Middle East, South Asia, Southwest Asia, and the Caspian Sea region.