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Ferrofluids are aqueous or non-aqueous solutions with colloidal particles of iron oxide nanoparticles with high magnetic characteristics. Their magnetic characteristics enable them to be controlled and manipulated when ferrofluids are exposed to magnetic fields. This study aims to inspect the features of unsteady stagnation point flow (SPF) and heat flux from the surface by incorporating ferromagnetic particles through a special kind of second-grade fluid (SGF) across a movable sheet with a nonlinear heat source/sink and magnetic field effect. The mass suction/injection and stretching/shrinking boundary conditions are also inspected to calculate the fine points of the features of multiple solutions.

The leading equations that govern the ferrofluid flow are reduced to a group of ordinary differential equations by applying similarity variables. The converted equations are numerically solved through the bvp4c solver. Afterward, study and discussion are carried out to examine the different physical parameters of the characteristics of nanofluid flow and thermal properties.

Multiple solutions are revealed to happen for situations of unsteadiness, shrinking as well as stretching sheets. Greater suction slows the separation of the boundary layers and causes the critical values to expand. The region where the multiple solutions appear is observed to expand with increasing values of the magnetic, non-Newtonian and suction parameters. Moreover, the fluid velocity significantly uplifts while the temperature declines due to the suction parameter.

The novelty of the work is to deliberate the impact of mass suction/injection on the unsteady SPF through the special second-grade ferrofluids across a movable sheet with an erratic heat source/sink. The confirmed results provide a very good consistency with the accepted papers. Previous studies have not yet fully explored the entire analysis of the proposed model.

A novel type of heat transfer fluid known as hybrid nanofluids is used to improve the efficiency of heat exchangers. It is observed from literature evidence that hybrid nanofluids outperform single nanofluids in terms of thermal performance. This study aims to address the stagnation point flow induced by Williamson hybrid nanofluids across a vertical plate. This fluid is drenched under the influence of mixed convection in a Darcy–Forchheimer porous medium with heat source/sink and entropy generation.

By applying the proper similarity transformation, the partial differential equations that represent the leading model of the flow problem are reduced to ordinary differential equations. For the boundary value problem of the fourth-order code (bvp4c), a built-in MATLAB finite difference code is used to tackle the flow problem and carry out the dual numerical solutions.

The shear stress decreases, but the rate of heat transfer increases because of their greater influence on the permeability parameter and Weissenberg number for both solutions. The ability of hybrid nanofluids to strengthen heat transfer with the incorporation of a porous medium is demonstrated in this study.

The findings may be highly beneficial in raising the energy efficiency of thermal systems.

The originality of the research lies in the investigation of the Darcy–Forchheimer stagnation point flow of a Williamson hybrid nanofluid across a vertical plate, considering buoyancy forces, which introduces another layer of complexity to the flow problem. This aspect has not been extensively studied before. The results are verified and offer a very favorable balance with the acknowledged papers.

This research paper aims to identify and provide insights into rejuvenation strategies in Kaş as a microtourism destination based on the views of stakeholders.

The research utilizes a single-case design, applying an inductive approach to analyze data collected from semi-structured interviews. Thematic analysis was employed to analyze the data.

The inductive thematic analysis yields nine different main themes: product transformation, integrated sustainable development strategies, cooperation, promotion through the right channels, stable tourism policy, selective tourism strategy, tourism awareness, access to tourist movements and management and tools for monitoring the quality and sustainability of tourism.

This research offers practical recommendations for regional authorities, residents and business stakeholders to foster sustainable tourism development by addressing resource utilization and existing challenges in the rejuvenation of Kaş.

This research contributes to theory by addressing the lack of applied research on the rejuvenation process in micro-tourism destinations, using Kaş (Turkey) as a case study. It identifies and emphasizes the unique challenges in microdestinations, enhancing our understanding and filling a critical knowledge gap. The identified rejuvenation strategies in Kaş are positioned to serve as a model for similar destinations, emphasizing their distinctive characteristics and challenges.

Political Science in the United States has focused too much on variable-oriented, quantitative methods and thus lost its ability to ask “big questions.” Stein Rokkan (d. 1979) was an eminent comparativist who asked big questions and provided such qualitative tools as conceptual maps, grids, and clustered comparisons. Ibn Khaldun (d. 1406), arguably the first social scientist, also asked big questions and provided a universal explanation about the dialectical relationship between nomads and sedentary people. This article analyzes to what extent Ibn Khaldun's concepts of asabiyya and sedentary culture help understand the rise and fall of the Muslim civilization. It also explores my alternative, class-based perspective in Islam, Authoritarianism, and Underdevelopment. Moreover, the article explores how Rokkan's analysis of cultural, geographical, economic, and religio-political variations within Western European states can provide insights to the examination of such variations in the Muslim world.

Material extrusion-based additive manufacturing is a prominent manufacturing technique to fabricate complex geometrical three-dimensional (3D) parts. Despite the indisputable advantages of material extrusion-based technique, the poor surface and subsurface integrity hinder the industrial application of this technology. The purpose of this study is introducing the hot air jet treatment (HAJ) technique for surface treatment of additive manufactured parts.

In the presented research, novel theoretical formulation and finite element models are developed to study and model the polishing mechanism of printed parts surface through the HAJ technique. The model correlates reflow material volume, layer width and layer height. The reflow material volume is a function of treatment temperature, treatment velocity and HAJ velocity. The values of reflow material volume are obtained through the finite element modeling model due to the complexity of the interactions between thermal and mechanical phenomena. The theoretical model presumptions are validated through experiments, and the results show that the treatment parameters have a significant impact on the surface characteristics, hardness and dimensional variations of the treated surface.

The results demonstrate that the average value of error between the calculated theoretical results and experimental results is 14.3%. Meanwhile, the 3D plots of Ra and Rq revealed that the maximum values of Ra and Rq reduction percentages at 255°C, 270°C, 285°C and 300°C treatment temperatures are (35.9%, 33.9%), (77.6%,76.4%), (94%, 93.8%) and (85.1%, 84%), respectively. The scanning electron microscope results illustrate three different treatment zones and the treatment-induced and manufacturing-induced entrapped air relief phenomenon. The measured results of hardness variation percentages and dimensional deviation percentages at different regimes are (8.33%, 0.19%), (10.55%, 0.31%) and (−0.27%, 0.34%), respectively.

While some studies have investigated the effect of the HAJ process on the structural integrity of manufactured items, there is a dearth of research on the underlying treatment mechanism, the integrity of the treated surface and the subsurface characteristics of the treated surface.

Studying the shear stress and pressure resulting on the walls of blood vessels, especially during high-pressure cases, which may lead to the explosion or rupture of these vessels, can also lead to the death of many patients. Therefore, it was necessary to try to control the shear and normal stresses on these veins through nanoparticles in the presence of some external forces, such as exposure to some electromagnetic shocks, to reduce the risk of high pressure and stress on those blood vessels. This study aims to examines the shear and normal stresses of electroosmotic-magnetized Sutterby Buongiorno’s nanofluid in a symmetric peristaltic channel with a moderate Reynolds number and curvature. The production of thermal radiation is also considered. Sutterby nanofluids equations of motion, energy equation, nanoparticles concentration, induced magnetic field and electric potential are calculated without approximation using small and long wavelengths with moderate Reynolds numbers.

The Adomian decomposition method solves the nonlinear partial differential equations with related boundary conditions. Graphs and tables show flow features and biophysical factors like shear and normal stresses.

This study found that when curvature and a moderate Reynolds number are present, the non-Newtonian Sutterby fluid raises shear stress across all domains due to velocity decay, resulting in high shear stress. Additionally, modest mobility increases shear stress across all channel domains. The Sutterby parameter causes fluid motion resistance, which results in low energy generation and a decrease in the temperature distribution.

Equations of motion, energy equation, nanoparticle concentration, induced magnetic field and electric potential for Sutterby nano-fluids are obtained without any approximation i.e. the authors take small and long wavelengths and also moderate Reynolds numbers.

This chapter aims to critically analyse the implications that the national protectionist policies have on the global supply and value chains and the relocation of production. The analysis is based on the assumptions that the global economy is facing the possibility of decoupling of many trade connections, and this trend favours de-globalisation processes that have long been promoted by populism, nationalism and economic protectionism. It is concluded that global supply, production and value chains although being economically efficient are no longer any more secure under national protectionist policies, and therefore, the relocation of production processes is mainly due to the increase in the level of income and wages of the developing countries that are the destination and which reduce the advantages to relocate.

In contrast to Ahmet Kuru's argument that a critical juncture occurred in the 11th century when a repressive anti-intellectual state-ulema alliance appeared, which destroyed the creative spirit of the previous centuries in Islam, this review argues that the critical juncture must be sought in the modern era with the development of citizenship in the Middle East.