Mirpur University of Science & Technology

The use of unmanned aerial vehicles (UAVs) for a variety of commercial, civilian, and defense applications has increased many folds in recent years.While UAVs are expected to transform future air operations, there are instances where they can be used for malicious purposes.In this context, the detection, classification, and tracking (DCT) of UAVs (DCT-U) for safety and surveillance of national air space is a challenging task when compared to DCT of manned aerial vehicles.In this survey, we discuss the threats and challenges from malicious UAVs and we subsequently study three radio frequency (RF)-based systems for DCT-U.These RF-based systems include radars, communication systems, and RF analyzers.Radar systems are further divided into conventional and modern radar systems, while communication systems can be used for joint communications and sensing (JC&S) in active mode and act as a source of illumination to passive radars for DCT-U.The limitations of the three RF-based systems are also provided.The survey briefly discusses non-RF systems for DCT-U and their limitations.Future directions based on the lessons learned are provided at the end of the survey.

The purpose of current study is to analyse the flow and thermal behaviour of Sutterby hybrid nanofluids, with particular attention given to an inclined magnetic field, viscous dissipation, heat source, Cattaneo-Christov heat flux, and thermal radiation model. In this work, we consider the Ag -Au/Blood based hybrid nanoparticle in the non-Newtonian Sutterby fluid in order to investigate how much they create the enhancement in the thermal conductivity. As the inclined magnetic field interacts with the electrically conducting fluid, its impacts on flow properties are examined. A more precise description of heat flow is obtained by using the Cattaneo-Christov model, which considers the speed limitations of heat conduction. The thermal transport analysis are investigated by using the thermal radiation, viscous dissipation and heat source or sink. The physical phenomena stated above have an impact on the formulation of the governing equations of mass, momentum and energy transfer. The model is established in the form of dimensional PDEs and suitable transformations is applied to translate the PDEs into non-dimensional ODEs. A mathematical model is created, and suitable numerical technique (RungeKutta 4 th order) are used to find solutions. The findings demonstrate the combined impact of these variables on the fluid flow's temperature distribution, velocity profiles, and heat transfer rates. The results reveals that Lorentz force or retardation force causes the velocity profile to decrease as the magnetic field increases. When comparing the Ag/blood case to the Ag-Au/blood case based on the Sutterby Deborah number, the depth of the thermal boundary layer rapidly drops. The hybrid nanofluid's temperature rises while its velocity decreases due to the nanoparticle volume percentage parameter. The friction drag heightens along with the Sutterby Deborah number and Power-law index estimates.

The flow and thermal performance of non-Newtonian fluid past under high shear and radiative heating over the rotating surface is essential in lubrication technology, energy systems, and thermal management devices, where the slip effects, surface roughness, and radiative heating cannot be neglected. The intention of the current work is to investigate the forced flow of generalized Newtonian fluid, namely Carreau fluid, across a heated rotated disk. We analyze the effects of both radial and azimuthal surface roughness on the laminar boundary-layer flows. The thermal behavior is examined by incorporating solar radiative heat flux and temperature dependent thermal conductivity. Viscous dissipation is described through the conversion of mechanical energy into internal energy via the Eckert number formulation, and the solar radiation impact is included in the energy equation through an existing radiative heat flow factor that represents surface absorption. The base-flow profiles for the velocity components are derived by modelling the surface with a partial slip approach. The current solutions are calculated by using the Carreau viscosity model. Under moderate von Karman similarity solutions, the base flow profiles are presented. A 5th-order Runge-Kutta computation scheme and a shooting approach are used to calculate the numerical results of the governing equations. Graphs and tables are used to provide a physical explanation of all the obtained findings for the temperature and mean flow profiles. The results reveal that the axial velocity is increased with increasing power law index but non-zero strength of axial flow. An increment in the axial roughness parameter decreases the radial profile. The radial velocity profile's non-zero convergence decreases when axial flow strength parameter is non-zero.

PurposeThe purpose of this study is to conduct a numerical investigation of heat and mass transfer in hybrid nanofluid (HNF) flow over inclined parallel rotating surface about the y-axis. The combined influences of surface rotation, inclination, magnetic field and activation energy each of which significantly affects velocity, temperature and concentration profiles are systematically analyzed.Design/methodology/approachThe working fluid is a polymer/carbon nanotube matrix nanocomposite, selected for its superior thermophysical properties and suitability in biomedical and engineering applications. To assess the effect of particle morphology, lamina-, tetrahedron- and hexahedron-shaped nanoparticles are considered. Following similarity transformations, the governing partial differential equations are converted into a system of ordinary differential equations, which are consequently solved numerically using MATLAB's bvp4c solver.FindingsThe results show that suction/injection (K) and Reynolds number (R) have significant impacts on momentum conductivity, whereas thermophoresis (Nt), Brownian motion (Nb) and heat generation (Q) increase fluid temperature. The chemical reaction parameter (Kr) and activation energy (E) increase the concentration field, whereas the Schmidt number (Sc) lowers it. Quantitatively, lamina-shaped nanoparticles increase the Nusselt number by 14%, while hexahedron-shaped particles enhance mass diffusivity by 11%. Activation energy reduces the diffusion boundary-layer thickness by nearly 9%.Originality/valueThe novelty of this work lies in coupling nanoparticle morphology inclined double-rotating geometry and activation energy effects into a unified framework. The outcomes convey design guidance for optimizing HNF applications in rotating machinery, electronic cooling and biomedical systems where efficient heat and mass transfer are critical.

This study focuses on synthesizing lead-manganese-based carboxylate complexes using metal salts and a pre-synthesized ligand, which were then calcined to produce mixed metal oxides (MMOs) for the degradation of dyes by photocatalysis. The study's goal was to assess the efficacy of Pb/Mn oxide compositions as catalysts for wastewater treatment under light exposure. FTIR, TGA, SEM-EDX, and XRD were used to analyze the synthesized materials, confirming their structural stability and successful synthesis. Photocatalytic tests revealed that all MMO compositions successfully destroyed bemacid red and violet dyes, with Pb-rich oxide (Pb: Mn = 7:3) having the greatest activity, reaching virtually 100 % dye elimination under acidic and oxidative conditions. The findings revealed that Mn supplied oxidative active sites, whereas Pb increased electron transport and redox flexibility, resulting in higher catalytic efficiency. Overall, the study showed that Pb/Mn mixed oxides were very efficient and reusable photocatalysts, providing a viable and affordable method for cleaning up wastewater polluted with dyes. This research offers a promising, sustainable approach to industrial wastewater treatment, contributing to environmental remediation and the advancement of industrial and environmental chemistry.