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This paper aims to study a non-Newtonian micropolar fluid flow over a bidirectional flexible surface for multiple exact solutions of momentum boundary layer and thermal transport phenomenon subject to wall mass flux, second-order slip and thermal jump conditions.

The coupled equations are transformed into ordinary differential equations using similarity variables. Analytical and numerical techniques are used to solve the coupled equations for single, dual or multiple solutions.

The results show that the stretching flow, shrinking flow, the wall drag, thermal profile and temperature gradient manifest large changes when treated for special effects of the standard parameters. The role of critical numbers is definitive in locating the domains for the existence of exact solutions. The nondimensional parameters, such as mass transfer parameter, bidirectional moving parameter, plate deformation strength parameter, velocity slips, material parameter, thermal jump and Prandtl number, are considered, and their physical effects are presented graphically. The presence of governing parameters exhibits special effects on the flow, microrotation and temperature distributions, and various exact solutions are obtained for the special parametric cases.

The originality and value of this work lie in its exploration of non-Newtonian micropolar fluid flow over a bidirectional flexible surface, highlighting the multiple exact solutions for momentum boundary layers and thermal transport under various physical conditions. The study provides insights into the effects of key parameters on flow and thermal behavior, contributing to the understanding of complex fluid dynamics.

The evaluation of high thermal efficiency has actively highlighted the unique behaviour of hybrid nanofluid. Thus, the purpose of this paper is to emphasize the hybrid nanofluid’s stagnation point in three-dimensional flow with magnetic field.

The defined ordinary differential equations systems are addressed using the bvp4c solver.

The results indicate that using dual solutions is possible as long as the physical parameters remain within their specified ranges. Hybrid nanofluid flow has been recognised for its superior heat transfer capabilities in comparison to both viscous flow and nanofluid flow. Furthermore, it has been demonstrated in the current study that augmenting the volume concentration of nanoparticles leads to a corresponding enhancement in the rate of heat transfer. When the velocity gradients ratio is augmented, there is a corresponding reduction in the thermal performance. The separation value grows as the magnetic parameter rises, which signifies the expansion of the boundary layer.

The originality of the paper highlights the general mathematical hybrid model of the three-dimensional problem with the magnetohydrodynamics (MHD) effect in the stagnation point flow. The comprehensive examination of the suggested model has not yet been thoroughly addressed in prior research.

This paper aims to study numerically the flow, heat transfer, and entropy generation of aqueous copper oxide-silver hybrid nanofluid over a down-pointing rotating vertical cone, with linear surface temperature (LST) and linear surface heat flux (LSHF), in the presence of a cross-magnetic field. In industrial applications, such as oil and gas plants, food industries, steel factories and nuclear packages, the real bodies may contain nonorthogonal walls and variable cross-section three-dimensional forms which this issue can clarify the importance of selective geometry in the present research.

The mass-based scheme is accomplished for the simulation, and the entropy generation and Bejan number will be analyzed in conjunction with the aforementioned model. It has been hypothesized that two types of boundary conditions (LST and LSHF) as well as five nanoparticle shapes (sphere, brick, cylinder, platelet and disk) present a collection of crucial results. The overseeing PDEs are changed over completely to the dimensionless ODEs, and these are solved by Runge–Kutta–Fehlberg approach combined with a shooting methodology for certain values of physical parameters.

Subsequent to the fantastic compromise of the computational outcomes with past reports, the outcomes are introduced to conduct the investigation of the hydrodynamics/thermal boundary layers, the skin friction and the Nusselt number, as well as entropy generation and Bejan number. A state of hybrid nanofluid, which exhibits a remarkable increase in heat transfer in comparison to the states of mono-nanofluid and regular fluid, has been found to have the highest Nusselt number; however, the skin friction values should always be taken into account and managed. The entropy generation improves with the mass of the second nanoparticle (silver), while the opposite pattern is exhibited for the Bejan number. Furthermore, the lowest value of entropy generation number belongs to the cylindrical shape of nanoparticles in the LST case. In final, a significant accomplishment of the current study is the accurate output of the mass-based scheme for an entropy analysis problem.

To the best of the authors’ knowledge, for the first time, in this study, a new development of natural convective flow of a hybrid nanofluid about the warmed (LST and LSHF) and down-pointing rotating vertical cone by the mass-based algorithm has been presented. The applied methodology considers the masses of base fluid (water) and nanoparticles (Ag and CuO) as an alternative to the first and second nanoparticles volume fraction. Indeed, the combination use of the Tiwari–Das nanofluid model and the mass-based hybridity algorithm for the entropy generation analysis can be the main novelty of this work.

This study aims to investigate the dual solutions for axisymmetric flow and heat transfer due to a permeable radially shrinking disk in copper oxide (CuO) and silver (Ag) hybrid nanofluids with radiation effect.

The partial differential equations that governed the problem will undergo a transformation into a set of similarity equations. Following this transformation, a numerical solution will be obtained using the boundary value problem solver, bvp4c, built in the MATLAB software. Later, analysis and discussion are conducted to specifically examine how various physical parameters affect both the flow characteristics and the thermal properties of the hybrid nanofluid.

Dual solutions are discovered to occur for the case of shrinking disk (λ < 0). Stronger suction triggers the critical values’ expansion and delays the boundary layer separation. Through stability analysis, it is determined that one of the solutions is stable, whereas the other solution exhibits instability, over time. Moreover, volume fraction upsurge enhances skin friction and heat transfer in hybrid nanofluid. The hybrid nanofluid’s heat transfer also heightened with the influence of radiation.

Flow over a shrinking disk has received limited research focus, in contrast to the extensively studied axisymmetric flow problem over a diverse set of geometries such as flat surfaces, curved surfaces and cylinder. Hence, this study highlights the axisymmetric flow due to a shrinking disk under radiation influence, using hybrid nanofluids containing CuO and Ag. Upon additional analysis, it is evidently shows that only one of the solutions exhibits stability, making it a physically dependable choice in practical applications. The authors are very confident that the findings of this study are novel, with several practical uses of hybrid nanofluids in modern industry.

This paper aims to present dual solutions for the two-dimension copper oxide with silver (CuO–Ag) and zinc oxide with silver (ZnO–Ag) hybrid nanofluid flow past a permeable shrinking sheet in a dusty fluid with velocity slip.

The governing partial differential equations for the two dust particle phases are reduced to the pertinent ordinary differential equations using a similarity transformation. Closed-form analytical solutions for the reduced skin friction and reduced Nusselt number, as well as for the velocity and temperature profiles, were presented, both graphically and in tables, under specific non-dimensional physical parameters such as the suction parameter, Prandtl number, slip parameter and shrinking parameter, which are also presented in both figures and tables.

The results indicate that for the shrinking flow, the wall skin friction is higher in the dusty fluid when compared with the clear (viscous) fluid. In addition, the effect of the fluid–particle interaction parameter to the fluid phase can be seen more clearly in the shrinking flow. Furthermore, multiple (dual, upper and lower branch solutions) are found for the governing similarity equations and the upper branch solution expanded with higher values of the suction parameter. It can be confirmed that the lower branch solution is unstable.

In practice, the study of the stretching/shrinking flow is crucially important and useful. Both the problems of steady and unsteady flow of a dusty fluid have a wide range of possible applications in practice, such as in the centrifugal separation of particles, sedimentation and underground disposal of radioactive waste materials.

Even though the problem of dusty fluid has been broadly investigated, very limited results can be found for a shrinking sheet. Indeed, this paper has succeeded to obtain analytically dual solutions. The stability analysis can be performed by following many published papers on stretching/shrinking sheets. Finally, the critical values and plotting curves for obtaining single or dual solution are successfully presented.

This paper aims to study numerically the steady natural convective heat transfer of a hybrid nanosuspension (Ag-MgO/H2O) within a partially heated/cooled trapezoidal region with linear temperature profiles at inclined walls under an effect of uniform Lorentz force. This investigation is useful for researchers studying in the area of cavity flows to know features of the flow structures and nature of hybrid nanofluid characteristics. In addition, a detailed entropy generation analysis has been performed to highlight possible regimes with minimal entropy generation rates.

The governing equations formulated using the Oberbeck–Boussinesq approach and single-phase nanoliquid model are transformed to a non-dimensional form by using non-dimensional variables. The obtained equations with appropriate boundary conditions are resolved by the finite difference technique. The developed code has been validated comprehensively. Analysis has been performed for a wide range of governing parameters, including Rayleigh number (Ra = 105), Prandtl number (Pr = 6.82), Hartmann number (Ha = 0–100), magnetic field inclination angle (φ = 0–?/2) and nanoparticles volume fraction (φ_hnf = 0 and 2%).

It has been shown that inclined magnetic field can be used to manage the energy transport performance. An inclusion of nanoparticles without Lorentz force influence allows forming more stable convective regime with descending heat plume in the central zone, while such a regime was performed for clear fluid only for moderate and high Hartmann numbers. Moreover, the average overall entropy generation can be decreased with a growth of the Hartmann number, while an addition of hybrid nanoparticles allows reducing this parameter for Ha = 30 and 50. The average Nusselt number can be increased with a growth of the nanoparticles concentration for low values of the magnetic field intensity.

Governing equations written using the conservation laws and dimensionless non-primitive variables have been resolved by the finite difference approach. The created numerical code has been verified by applying the grid independence test and computational outcomes of other researchers. The comprehensive analysis for various key parameters has been performed.

This paper aims to extend the scope of previous studies on education-occupation mismatch to explicitly focus on the role high school track choices have on the risk of being mismatched in the labor market.

The paper uses the most exhaustive available database regarding the early-career paths of university graduates in Romania. Using a novel matching technique, entropy balancing (EB), our study relies on multinomial logit models and logit regressions to estimate the effect of the completed high school track on the likelihood of being mismatched in the labor market. The empirical analysis focuses on two types of education-occupation mismatches: horizontal and vertical mismatches.

We show that studying a different field in college compared to the completed high school track increases the risk of being skill mismatched in the first job after graduation. Five years after college graduation, the influence of the high school track fades, while being skill mismatched in the first employment plays a more important role. In contrast, we find no evidence that pursuing a college major unrelated to the completed high school track increases the probability of being overeducated. However, being overeducated in the first job increases the risk of being overeducated five years later.

The study brings new reliable evidence on the extent to which high school track choices may contribute to the risk of being mismatched in the labor market.

Generation Z has already begun to impact our world, particularly through their social change behaviors, personal characteristics, volunteering, and entrepreneurial endeavors. In particular, Gen Zers around the world like to stay informed of societal issues, share information with others about those issues, and engage in personal behaviors and/or lifestyle changes to address those issues.

The purpose of this paper is to examine souvenir sellers as unconventional micro-entrepreneurs, focusing on non-economic motives for selling.

A qualitative methodology was used. Semi-structured interviews were undertaken with 20 souvenir sellers in the Romanian city of Timişoara. These were analysed using thematic analysis which identified four non-economic motives for selling souvenirs.

Souvenir selling was a matter of choice rather than economic necessity. While these sellers were entrepreneurs who were seeking to generate income, non-economic motives were also important. These included passion, hobbyism and interpersonal interactions with customers. Some sellers considered themselves as cultural intermediaries, representing place and tradition to their customers.

In a European context, selling souvenirs can be a matter of lifestyle choice rather than economic necessity. Micro-entrepreneurs are frequently motivated by passion, hobbyism and interpersonal rewards as much as financial profit. This represents a particular form of unconventional or lifestyle entrepreneurship.

The encouragement of on-street souvenir sellers by urban managers can add vibrancy to a city, enhancing the experiences of local communities and visitors. This can also encourage the development of an artisan class to enhance a city’s reputation as a creative place.

Souvenir sellers are little researched, and this is one of few studies that has investigated this group outside Developing World contexts. This study emphasises the importance of unconventional entrepreneurship and non-economic motives for selling souvenirs in a European context.

本研究将纪念品销售商这类非传统微型企业家群体作为研究对象, 重点关注其销售纪念品的非经济动机。

本研究主要采用定性的研究方法, 对20位罗马尼亚蒂米什瓦拉市的纪念品销售商进行了半结构化访谈。通过对访谈结果的主题分析, 本研究发现并提炼出了纪念品销售商的4种非经济动机。

纪念品销售并非经济上的必然选择, 而更多地体现为一种个体的自主决策。尽管这些销售商本质上仍是追求经济回报的企业家, 其销售活动背后的非经济动机同样重要。这些动机包括对事业的激情、业余爱好, 以及与顾客之间的人际互动等。一些销售商视自身为文化传播的中介, (在销售活动中)向顾客展示地域与传统的象征。

在欧洲的语境下, 纪念品销售通常被视为一种生活方式的选择而非经济的迫切需要。微型企业家的销售行为通常受到对事业的激情、业余爱好以及人际关系的多重因素的推动, 而非单纯由经济利益驱使。这呈现出一种独特的非传统生活方式创业形态。

城市管理者可以通过默许纪念品销售商在市区进行销售活动的方式为城市注入活力, 提升当地社区和游客的体验。这同时有助于培养手工艺术家阶层, 进一步增强城市作为创意之地的声誉。

纪念品销售商的相关研究相对比较有限, 本研究在探讨这一群体时跳脱了发展中国家的框架, 同时强调了在欧洲环境下非传统创业和销售纪念品的非经济动机的重要性。

Se utilizó una metodología cualitativa. Se realizaron entrevistas semiestructuradas a 20 minoristas de recuerdos (souvenirs) de la ciudad rumana de Timişoara. Las entrevistas se analizaron mediante un análisis temático que permitió identificar cuatro motivos no económicos para la comercialización de recuerdos.

Este artículo examina a los comerciantes de souvenirs como micro emprendedores no convencionales, centrándose en los motivos no económicos para su venta.

La venta de souvenirs era una cuestión de elección más que de necesidad económica. Aunque estos vendedores eran emprendedores que buscaban generar ingresos, los motivos no económicos también eran importantes. Entre ellos, la pasión, la afición y las interacciones interpersonales con los clientes. Algunos vendedores se consideraban intermediarios culturales que representaban el lugar y la tradición ante sus clientes.

En un contexto europeo, la venta de recuerdos puede ser una cuestión de elección de estilo de vida más que de necesidad económica. Los micro emprendedores suelen estar motivados por la pasión, la afición y las recompensas interpersonales tanto como por el beneficio económico. Esto representa una forma particular de espíritu empresarial no convencional o de estilo de vida.

El fomento de los vendedores ambulantes de souvenirs por parte de los gestores urbanos puede aportar dinamismo a una ciudad, mejorando las experiencias de las comunidades locales y de los visitantes. Esto también puede fomentar el desarrollo de una clase artesanal para mejorar la reputación de una ciudad como lugar creativo.

Los comerciantes de souvenirs están poco investigados, y éste es uno de los pocos estudios que ha investigado este grupo fuera de los contextos del mundo en desarrollo. Destaca la importancia del espíritu empresarial no convencional y de los motivos no económicos para la venta de recuerdos en un contexto europeo.

Technological progress is a determining factor in the factors leading to economic and social well-being. Simultaneously, the development of a sustainable economy is based on the conservation of resources. In the energy sector, this fact can be corroborated with the reduction of energy consumption, thus increasing economic efficiency. On the one hand, improving energy efficiency contributes to increasing the quality of life, productivity, and, implicitly, the economy, but on the other hand, it leads to excess energy use – this behavioral change is known as rebound. The research estimates the rebound effect at the macroeconomic level for European countries in the period 2000–2019, referring the analysis to each country's gross domestic product (GDP) and energy consumption, as well as comparing the preaccession and postaccession periods of Romania in the EU space. The rebound effect is determined using multidimensional analysis methods, depending on the GDP of each country as well as the behavior of each in the use of energy resources in industry, agriculture, and services. Although the study results confirm the strong link between energy consumption and GDP at the level of each state, they did not show considerable changes between countries at the level of the two periods.