Search results

This paper aims to study passive control techniques for transonic flow over a backward-facing step (BFS) using square-lobed trailing edges. The study investigates the efficacy of upward and downward lobe patterns, different lobe widths and deflection angles on flow separation, aiming for a deeper understanding of the flow physics behind the passive flow control system.

Large Eddy Simulation and Reynolds-averaged Navier–Stokes were used to evaluate the results of the study. The research explores the impact of upward and downward patterns of lobes on flow separation through the effects of different lobe widths and deflection angles. Numerical methods are used to analyse the behaviour of transonic flow over BFS and compared it to existing experimental results.

The square-lobed trailing edges significantly enhance the reduction of mean reattachment length by up to 80%. At Ma = 0.8, the up-downward configuration demonstrates increased effectiveness in reducing the root mean square of pressure fluctuations at a proximity of 5-step height in the wake region, with a reduction of 50%, while the flat-downward configuration proves to be more efficient in reducing the root mean square of pressure fluctuations at a proximity of 1-step height in the near wake region, achieving a reduction of 71%. Furthermore, the study shows that the up-downward configuration triggers early spanwise velocity fluctuations, whereas the standalone flat-downward configuration displays less intense crosswise velocity fluctuations within the wake region.

The findings demonstrate the effectiveness of square-lobed trailing edges as passive control techniques, showing significant implications for improving efficiency, performance and safety of the design in aerospace and industrial systems.

This paper demonstrates that the square-lobed trailing edges are effective in reducing the mean reattachment length and pressure fluctuations in transonic conditions. The study evaluates the efficacy of different configurations, deflection angles and lobe widths on flow and provides insights into the flow physics of passive flow control systems.

This study uses a Kaleidoscope Career (KC) approach to explore how UAE women managers experience their careers, the advancement in management and the career models they encounter.

This study employs an interpretative phenomenological approach to analyse in-depth face-to-face interviews with 22 Emirati women in middle and senior management positions across various industries in both the public and private sectors.

This research is significant in uncovering career advancement mechanisms and three career models: “my life is not elsewhere,” “seizing opportunities” and “wholehearted dedication to the country.” These models highlight women managers' pivotal role in UAE's economic development.

This study is confined to a convenience sample of women managers from Abu Dhabi, Dubai and Sharjah. While not fully representative of all local women, the findings on career advancement mechanisms and Emirati women managers' non-traditional career paths hold theoretical significance. The results challenge the uncritical adoption of Western career models, highlighting the need to consider alternative career models and advancement mechanisms.

This research expands the authors' knowledge of career advancement mechanisms and models experienced by Emirati women, offering insights for enhancing gender equality in Arab world managerial roles.

These findings open new research avenues to explore Emirati women's careers beyond the largest Emirates and assess their broader economic and societal contributions.

This study aims to investigate student mentors' perceptions of peer mentor relationships in a health professions education program.

The design uses embodied hermeneutic phenomenology. The data comprise 10 participant interviews and visual “body maps” produced in response to guided questions.

The findings about student mentors' perceptions of peer mentor relationships include a core theme of nurturing a trusting learning community and five related themes of attunement to mentees, commonality of experiences, friends with boundaries, reciprocity in learning and varied learning spaces.

The study contributes original insights by highlighting complexity, shifting boundaries, liminality, embodied social understanding and trusting intersubjective relations as key considerations in student peer mentor relationships.

The purpose of this paper is to design a simple and accurate a-posteriori Lagrangian-based error estimator is developed for the class of backward differentiation formula (BDF) algorithms with variable time step size, and the adaptive time-stepping in BDF algorithms is demonstrated for efficient time-dependent simulations in fluid flow and heat transfer.

The Lagrange interpolation polynomial is used to predict the time derivative, and then the accurate primary result is obtained by the Gauss integral, which is applied to evaluate the local error. Not only the generalized formula of the proposed error estimator is presented but also the specific expression for the widely applied BDF1/2/3 is illustrated. Two essential executable MATLAB functions to implement the proposed error estimator are appended for practical applications. Then, the adaptive time-stepping is demonstrated based on the newly proposed error estimator for BDF algorithms.

The validation tests show that the newly proposed error estimator is accurate such that the effectivity index is always close to unity for both linear and nonlinear problems, and it avoids under/overestimation of the exact local error. The applications for fluid dynamics and coupled fluid flow and heat transfer problems depict the advantage of adaptive time-stepping based on the proposed error estimator for time-dependent simulations.

In contrast to existing error estimators for BDF algorithms, the present work is more accurate for the local error estimation, and it can be readily extended to practical applications in engineering with a few changes to existing codes, contributing to efficient time-dependent simulations in fluid flow and heat transfer.

A real-time production scheduling method for semiconductor back-end manufacturing process becomes increasingly important in industry 4.0. Semiconductor back-end manufacturing process is always accompanied by order splitting and merging; besides, in each stage of the process, there are always multiple machine groups that have different production capabilities and capacities. This paper studies a multi-agent based scheduling architecture for the radio frequency identification (RFID)-enabled semiconductor back-end shopfloor, which integrates not only manufacturing resources but also human factors.

The architecture includes a task management (TM) agent, a staff instruction (SI) agent, a task scheduling (TS) agent, an information management center (IMC), machine group (MG) agent and a production monitoring (PM) agent. Then, based on the architecture, the authors developed a scheduling method consisting of capability & capacity planning and machine configuration modules in the TS agent.

The authors used greedy policy to assign each order to the appropriate machine groups based on the real-time utilization ration of each MG in the capability & capacity (C&C) planning module, and used a partial swarm optimization (PSO) algorithm to schedule each splitting job to the identified machine based on the C&C planning results. At last, we conducted a case study to demonstrate the proposed multi-agent based real-time production scheduling models and methods.

This paper proposes a multi-agent based real-time scheduling framework for semiconductor back-end industry. A C&C planning and a machine configuration algorithm are developed, respectively. The paper provides a feasible solution for semiconductor back-end manufacturing process to realize real-time scheduling.

While the main emotional labor strategies are well-documented, the manner in which professionals navigate emotional rules within the workplace and effectively perform emotional labor is less understood. With this contribution, I aim to unveil “the good, the bad and the ugly” of emotional labor as a dynamic theatrical performance.

Focusing on three geriatric long-term care units within a French public hospital, this qualitative study relies on two sets of data (observation and interviews). Deeply rooted within the field of study, the chosen methodological approach substantializes the subtle hues of the emotional experience at work and targets resonance rather than generalization.

Using the theatrical metaphor, this research underlines the role of space in the practice of emotional labor in a unique way. It identifies the main emotionalized zones or emotional regions (front, back, transitional, mixed) and details their characteristics, before unearthing the nonlinearity and polyphonic quality of emotional labor performance and the versatility needed to that effect. Indeed, this research shows how health-care professionals juggle with the specificities of each region, as well as how space generates both constraints and resources. By combining static and dynamic prisms, diverse instantiations of hybridity and spatial in-betweens, anchored in liminality and trajectories, are revealed.

This research adds to the current body of literature on the concept of emotional labor by shedding light on its highly dynamic and interactional nature, revealing different levels of porosity between emotional regions and how the characteristics of each type of area can taint others and increase/decrease the occupational health costs of emotional labor. The study also raises questions about the interplay of emotional labor performance with the level of humanization/dehumanization of elderly people. Given the global demographics about an aging population, this gives food for thought at a social level.

This paper aims to present a novel adaptive sliding mode control (ASMC) method based on the predefined performance barrier function for reusable launch vehicle under attitude constraints and mismatched disturbances.

A novel ASMC based on barrier function is adopted to deal with matched and mismatched disturbances. The upper bounds of the disturbances are not required to be known in advance. Meanwhile, a predefined performance function (PPF) with prescribed convergence time is used to adjust the boundary of the barrier function. The transient performance, including the overshoot, convergence rate and settling time, as well as the steady-state performance of the attitude tracking error are retained in the predetermined region under the barrier function and PPF. The stability of the proposed control method is analyzed via Lyapunov method.

In contrast to conventional adaptive back-stepping methods, the proposed method is comparatively simple and effective which does not need to disassemble the control system into multiple first-order systems. The proposed barrier function based on PPF can adjust not only the switching gain in an adaptive way but also the convergence time and steady-state error. And the efficiency of the proposed method is illustrated by conducting numerical simulations.

A novel barrier function based ASMC method is proposed to fit in the amplitude of the mismatched and matched disturbances. The transient and steady-state performance of attitude tracking error can be selected as prior control parameters.

This paper aims to present the design development and measurement of two aerodynamic slotted X-bands back-to-back planer substrate-integrated rectangular waveguide (SIRWG/SIW) to Microstrip (MS) line transition for satellite and RADAR applications. It facilitates the realization of nonplanar (waveguide-based) circuits into planar form for easy integration with other planar (microstrip) devices, circuits and systems. This paper describes the design of a SIW to microstrip transition. The transition is broadband covering the frequency range of 8–12 GHz. The design and interconnection of microwave components like filters, power dividers, resonators, satellite dishes, sensors, transmitters and transponders are further aided by these transitions. A common planar interconnect is designed with better reflection coefficient/return loss (RL) (S₁₁/S₂₂ ≤ 10 dB), transmission coefficient/insertion loss (IL) (S₁₂/S₂₁: 0–3.0 dB) and ultra-wideband bandwidth on low profile FR-4 substrate for X-band and Ku-band functioning to interconnect modern era MIC/MMIC circuits, components and devices.

Two series of metal via (6 via/row) have been used so that all surface current and electric field vectors are confined within the metallic via-wall in SIW length. Introduced aerodynamic slots in tapered portions achieve excellent impedance matching and tapered junctions with SIW are mitered for fine tuning to achieve minimum reflections and improved transmissions at X-band center frequency.

Using this method, the measured IL and RLs are found in concord with simulated results in full X-band (8.22–12.4 GHz). RLC T-equivalent and p-equivalent electrical circuits of the proposed design are presented at the end.

The measurement of the prototype has been carried out by an available low-cost X-band microwave bench and with a Keysight E4416A power meter in the microwave laboratory.

The transition is fabricated on FR-4 substrate with compact size 14 mm × 21.35 mm × 1.6 mm and hence economical with IL lie within limits 0.6–1 dB and RL is lower than −10 dB in bandwidth 7.05–17.10 GHz. Because of such outstanding fractional bandwidth (FBW: 100.5%), the transition could also be useful for Ku-band with IL close to 1.6 dB.

The expected learning outcomes are to understand key frameworks and tools for global leaders through the application of widely used theoretical frameworks on a written business case, understand the role of the leader in a team, apply theories of change to situations to anticipate courses of events and evaluate and apply relevant theory to assess a leader’s character and personality.

Hassan Allam Holding (HAH) was a family-owned Egyptian engineering, construction and infrastructure company managed by co-Chief Executive Officers and brothers Amr and Hassan Allam. HAH experienced significant growth and success, but eventually, it reached a point where its family governance structure could no longer sustain further growth. Amr and Hassan realized this and started planning to transition toward a corporate governance structure. In 2016, they managed to get the International Finance Corporation on board as an equity partner, and this helped propel the governance transition, but they still needed to find a way to convince the family to step back. This case study can help students understand the issues that may occur during a change within an established organization of any size. The case study considers the implications the change may have on the leader, his personality and his character and how it shapes the leader in question as an outcome. This case study has been designed to be used in one or two sessions and can be offered in management or leadership courses at an undergraduate or graduate level.

This case study is intended for graduate and undergraduate students studying a leadership or management course. It can help students comprehend the challenges of a family-owned business and how change is associated with such businesses. The case also considers how leaders are shaped by effectively managing conflict. This case can be considered as Level 1 on a 1–3 scale, as the full description of the situation is given in the case and the task of the students is to analyze the leader and his decisions using various academic concepts and theories (Erskin et al., 2003).

Teaching notes are available for educators only.

CSS 3: Entrepreneurship