Search Results (368)

This paper presents an online efficiency optimization strategy for a six-phase induction generator (6PIG) operating in both healthy and faulty modes for micro-hydropower applications. The proposed method is based on an extended Loss Model Control (LMC) approach, in which the direct axis stator current Id is dynamically optimized in real time to minimize the total electrical losses. Unlike conventional LMC strategies, this method explicitly incorporates switching losses into the loss model, along with stator and rotor copper losses and iron losses. The optimization problem is solved using a numerical minimization routine, allowing the control system to adapt continuously to variations in torque requests. The proposed approach is validated under both healthy and faulty configurations of the 6PIG. It is implemented and tested through simulation in MATLAB/Simulink^® and experimentally validated on a 24 kW squirrel cage six-phase induction generator (SC6PIG). The results are compared in terms of power losses, energy saving, and efficiency. Full article

As organizations become increasingly projectified, safeguarding the resilience of project professionals and teams emerges as a critical organizational challenge. Adopting a systems lens, we investigate how agile mindsets and agile practices function as systemic antecedents of resilience at the individual and team levels. Eleven semi-structured interviews with experienced project managers, product owners, and team members from diverse industries were analyzed through inductive thematic coding and system mapping. The findings show that mindset supplies psychological resources—self-efficacy, openness and a learning orientation—while practices such as team autonomy, iterative delivery and transparent communication provide structural routines; together they trigger five interlocking mechanisms: empowerment, fast responsiveness, holistic team dynamics, stakeholder-ecosystem engagement and continuous learning. These mechanisms reinforce one another in feedback loops that boost a project system’s adaptive capacity under volatility. The synergy of mindset and practices is especially valuable in hybrid or traditionally governed projects, where cognitive agility offsets structural rigidity. This study offers the first multi-level, systems-based explanation of agile antecedents of resilience and delivers actionable levers for executives, transformation leaders, project professionals, and HR specialists aiming to sustain talent performance in turbulent contexts. Full article

The Belt and Road Initiative (BRI) is the first and currently the most expansive global infrastructure initiative, notably for its scale and emphasis on connectivity. In response, alternative initiatives such as the Partnership for Global Infrastructure and Investment (PGII) and Free and Open Indo-Pacific Strategy (FOIP), including their components the Blue Dot Network (BDN) and Partnership for Quality Infrastructure (PQI), as well as Global Gateway (GG) and the Three Seas Initiative (3SI), have emerged to counterbalance the BRI’s influence and promote more transparent, sustainable, and rules-based infrastructure frameworks. This review investigates how global and regional infrastructure initiatives—namely PGII/BDN, GG, FOIP/PQI, and 3SI—compare with the BRI in terms of development objectives, implementation models, institutional structures, and implications for developing economies. Adopting an inductive approach, this review identifies key themes from the literature to evaluate these initiatives across seven dimensions: (1) infrastructure objectives, (2) the quality and transparency of investments, (3) investment policy orientation, (4) trade policy orientation, (5) inclusivity and regional integration, (6) coordination mechanisms, and (7) environmental sustainability. While PGII/BDN, GG, FOIP/PQI, and 3SI appear well-positioned to address some of BRI’s shortcomings, the evidence does not clearly favour one model over another in terms of achieving welfare-enhancing outcomes and bridging development gaps. Nonetheless, strategic competition and complementarities among the connectivity policies of multiple initiatives can ultimately contribute to more accountable, multidimensionally sustainable, and socially inclusive infrastructure development. We also illustrate how stated preference methods, i.e., willingness to pay (WTP) and willingness to accept (WTA), can be used to quantify the value of soft infrastructure, particularly public preferences for sustainable investment and norm diffusion, which are central to evaluating the social welfare gains from participating in these initiatives. Full article

Background/Objectives: Mental disorders that emerge during adolescence frequently extend into adulthood, predicting poor academic and employment outcomes and heavy societal burdens. Novel efforts to improve youth mental health have transitioned from clinical recovery, typically focused on a cure, to a strength-based approach to wellbeing in supporting youth within mental health services. Mental health scholars have appealed for interventions to adopt an ecological system of care approach that integrates the principal caregivers in a young person’s life. Despite preliminary literature indicating the importance of caregivers, little research has focused on the caregiver’s role in supporting personal recovery in youth. Methods: This study sought to understand the role of caregivers in youth recovery by employing a qualitative design to inductively analyze the narratives from nine semi-structured interviews with caregivers. Additionally, deductive analysis explored the core five underpinnings of personal recovery connectedness, hope, identity, meaning, and empowerment (CHIME). Results: A thematic analysis of the literature identified five themes: providing unconditional love and positive regard; encouraging connection with peers; co-creating a sense of purpose, meaning, and hope; supporting assertiveness and advocacy; and promoting strength and opportunity for mastery aligning with the CHIME framework. The findings will allow health services to understand caregivers’ roles better, thus providing information to guide recovery-oriented and family-centered care. Full article

Despite advanced aviation safety systems, recurring operational failures demonstrate that current safety management system (SMS) implementation practices remain predominantly reactive, with organizations adopting SMS frameworks theoretically embracing Safety-II philosophy while continuing Safety-I-oriented reactive management. This study develops an integrated framework for implementing both Safety-I and Safety-II principles in aviation safety management, addressing the gap between SMS theoretical requirements and actual implementation. Using the HEAR (human error analysis and reduction) framework, we analyzed three representative aviation cases involving FMS operation, turbulence response, and aircraft energy management through a qualitative multiple-case study design. Data collection utilized internal safety reports, official investigation reports, and reconstructed operational scenarios. The analysis employed a four-phase approach integrating predetermined categorization with inductive pattern recognition. Results revealed that 87% of all causes were organizational factors—6.7 times higher than individual/task factors (13%)—yet safety management responses primarily target individual behaviors. We defined “flight crew’s resilient behavior” and developed implementation guidelines by integrating the HEAR framework with the LPAC (learn, plan, adapt, coordinate) model and PAM (pressures, adaptations, and manifestations) framework. Effectiveness evaluation demonstrated a transition from 54 discrete contributing factors to 19 systematically related factors with clearer implementation pathways. Our integrated framework enables organizations to systematically implement both Safety-I analytical capabilities and Safety-II adaptive responses, transforming safety management from reactive “failure prevention” to proactive “success expansion”. Full article

This paper introduces a novel field-oriented control (FOC) strategy for an open-end stator three-phase winding induction motor (OEW-TP-IM) using dual space vector modulation-pulse width modulation (SVM-PWM) inverters. This configuration reduces common mode voltage at the motor’s terminals, enhancing efficiency and reliability. The study presents a backstepping control approach combined with a mean value theorem (MVT)-based observer to improve control accuracy and stability. Stability analysis of the backstepping controller for key control loops, including flux, speed, and currents, is conducted, achieving asymptotic stability as confirmed through Lyapunov’s methods. An advanced observer using sector nonlinearity (SNL) and time-varying parameters from convex theory is developed to manage state observer error dynamics effectively. Stability conditions, defined as linear matrix inequalities (LMIs), are solved using MATLAB R2016b to optimize the observer’s estimator gains. This approach simplifies system complexity by measuring only two line currents, enhancing responsiveness. Comprehensive simulations validate the system’s performance under various conditions, confirming its robustness and effectiveness. This strategy improves the operational dynamics of OEW-TP-IM machine and offers potential for broad industrial applications requiring precise and reliable motor control. Full article

This paper presents a Space Vector Modulation (SVM) method with a novel zero vector distribution system for electrical vehicle drives with a six-phase induction motor working under the Direct Field-Oriented Control (DFOC) method. Different SVM methods are described and compared, and a new approach with long vectors only and a special zero vector distribution, that compensates for the third harmonic component is proposed. The DFOC method is described and the influence of the applied modulation method on six-phase motor currents is shown. Results of our experimental studies on the DFOC method are presented and discussed. The proposed modulation method for a six-phase Voltage Source Inverter can be applied in fault-tolerant electrical vehicles. Full article

The sensorless control of doubly fed induction machine (DFIM) rotor magnetic flux based on a model reference adaptive system (MRAS) is proposed to improve the reliability of a large-scale variable-speed pumped storage (VSPS) system and reduce operation and maintenance costs. The existing sensorless control of doubly fed induction machines (DFIMs) is mostly focused on generator operation, making it difficult to apply to the VSPS system. The proposed strategy realizes the reversible operations of the VSPS through the design of an adaptive law under variable operating conditions, eliminating mechanical sensors, and possessing the characteristics of simple implementation and accurate identification. The mathematical model of the DFIM in a VSPS system is constructed, and an MRAS vector control strategy based on stator voltage orientation is established. The rotor angle and speed under reversible operating conditions are effectively identified by dynamically adjusting the angle error between the rotor flux reference model and the adaptive model to approach zero. Subsequently, comparative analysis with the closed-loop direct detection method verifies the advantages of the proposed strategy. The proposed control method can accurately identify rotor position and speed in the pumping and power generation conditions of the VSPS system and it demonstrates robust adaptability. Full article

The Dehbid region, located in the southern part of the Sanandaj–Sirjan Zone (SSZ), is a significant iron oxide mining district with over 20 iron oxide deposits (IODs) and reserves of up to 50 million tons of iron oxide ores. The region features a NW–SE oriented ductile shear zone, parallel to the Zagros thrust zone, experienced significant deformation. Detailed structural studies indicate that the iron mineralization is primarily stratiform to stratabound and hosted in late Triassic to early Jurassic silicified dolomites and schists. These ore deposits consist of lenticular iron oxide orebodies and exhibit various structures and textures, including banded, laminated, folded, disseminated, and massive forms of magnetite and hematite. The Fe₂O₃ content in the mineralized layers varies from 30 to 91 wt%, whereas MnO has an average of 3.9 wt%. The trace elements are generally low, except for elevated concentrations of Cu (up to 4350 ppm) and Zn (up to 3270 ppm). Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) analysis of magnetite reveals high concentrations of Mg, Al, Si, Mn, Ti, Cu, and Zn, with significant depletion of elements such as Ga, Ge, As, and Nb. This study refutes the hypothesis of vein-like or hydrothermal genesis, providing evidence for a sedimentary origin based on the trace element geochemistry of magnetite and LA-ICP-MS geochemical data. The Dehbid banded iron ores (BIOs) are thought to have formed under geodynamic conditions similar to those of BIOs in back-arc tectonic settings. The combination of anoxic conditions, submarine hydrothermal iron fluxes, and redox fluctuations is essential for the formation of these deposits, suggesting that similar iron–manganese deposits can form during the Phanerozoic under specific geodynamic and oceanographic conditions, particularly in tectonically active back-arc environments. Full article

Since epoxy resin has excellent mechanical and insulating qualities, it is frequently utilized in dry transformers. Low thermal conductivity, however, has prevented it from be developed further in high-frequency and large-capacity dry transformers. This study describes the preparation of sheet boron nitride (BN)/epoxy resin composites with superior electrical, thermal, and mechanical properties through the application of varying strengths of high-frequency alternating-current (AC) electric fields. Using an optical microscope, the orienting process of BN in epoxy resin under an electric field was studied. In parallel, tests were conducted on the BN/epoxy resin composites made with varying electric field strengths. The findings indicate that the preparation using a high-frequency AC electric field decreases BN agglomeration and improves the composite’s properties. The overall performance is comparatively ideal when the applied electric field strength is 30 V/mm, the tensile strength is 48.3 MPa, the breakdown field strength is 37.65 kV/mm, and the thermal conductivity of the BN/epoxy resin composite is 0.95 W/(m·K). The thermal conductivity greatly increased and BN was organized into chains when the electric field approached 60 V/mm. The tensile strength and breakdown field strength, on the other hand, declined. Full article

This paper proposes a sensorless field-oriented control (FOC) strategy for permanent magnet synchronous motors (PMSMs), focusing on rotor flux position estimation based on back-electromotive force (back-EMF) signals. The limitations of conventional phase-locked loop (PLL) techniques for rotor flux position estimation along the motor shaft are analyzed, and an enhanced PLL structure is developed to address these deficiencies.In electric vehicle traction applications, precise flux position estimation alone is insufficient; accurate generation of d–q-axis current commands is equally critical. To address this need, a zero-pole-free PI regulator is designed within the PLL module, enabling more accurate flux estimation. Additionally, a gradient-based self-tuning algorithm is employed to identify system parameters, particularly the stator inductance, enabling the controller to optimize current command generation.Comprehensive system-level simulations have been conducted to validate the effectiveness of the proposed sensorless control scheme. Comparative studies demonstrate that the proposed method significantly improves feasibility and robustness for practical PMSM drive applications. Full article

The integration of renewable energy sources, such as wind power, into the electrical grid is essential for the development of sustainable energy systems. Doubly fed induction generators (DFIGs) have been significantly utilized in wind energy conversion systems (WECSs) because of their efficient power generation and variable speed operation. However, optimizing wind power extraction at variable wind speeds remains a major challenge. To address this, an artificial neural network (ANN) is adopted to predict the optimal shaft speed, ensuring maximum power point tracking (MPPT) for a wind energy-driven DFIG connected to a matrix converter (MC). The DFIG is controlled via field-oriented control (FOC), which allows independent power output regulation and separately controls the stator active and reactive power components. Through its compact design, bidirectional power flow, and enhanced harmonic performance, the MC, which is controlled by the simplified Venturini modulation technique, improves the efficiency and dependability of the system. Simulation outcomes confirm that the ANN-based MPPT enhances the power extraction efficiency and improves the system performance. This study shows how wind energy systems can be optimized for smart grids by integrating advanced control techniques like FOC and simplified Venturini modulation with intelligent algorithms like ANN. Full article

Measures of sexual orientation and family functioning are widely used among sexual minority populations. However, data on whether these measures are culturally syntonic and responsive to the needs of a particular population, such as Hispanic sexual minority youth (HSMY), are lacking. Therefore, this study assessed whether HSMY understand measures of sexual orientation and family functioning as intended. Authors conducted individual interviews with five HSMY to evaluate the face validity of a measure of sexual orientation (i.e., Klein Sexual Orientation Grid) and measures of family functioning (i.e., Parent–Adolescent Communication Scale, Parenting Practices Scale, Parental Monitoring of Peers). Data were analyzed using a general inductive approach. For the sexual orientation measure, five themes were identified related to the: (1) clarity of questions, (2) challenging nature of questions, (3) difficulty of responses, (4) suggestions to improve response options, and (5) need for questions to include gender identity. For family functioning, three themes were identified: (1) relevance of the measures to sexual minority youth, (2) the importance of understanding family history and cultural context, and (3) capturing the context of how sexual minority status and disclosure impact family functioning. HSMY had generally positive feedback regarding these measures; however, they also suggested specific changes associated with wording and specificity of the measures to make them more relevant to HSMY’s unique needs. Full article

Accurate estimation of the rotor flux angle remains a significant challenge when conventional direct or indirect field-oriented control (FOC) strategies are applied to induction motor drives. This paper proposes a novel method for determining the rotor flux angle under steady-state conditions using only stator voltage and current measurements. An adjustable steady-state detection mechanism is introduced and integrated into a phase-locked loop (PLL)-based indirect field-oriented framework to enable a smooth injection of the actual rotor flux angle into the control system. Both simulation and experimental results validate the effectiveness of the proposed method, demonstrating a significant reduction in stator current compared to conventional FOC approaches under identical load torque conditions. Full article

This paper presents a twisting controller (TC) based on a high-order sliding mode observer (HOSMO) for linear induction motors (LIMs), accounting for dynamic end effects. Based on the LIM model in the field-oriented frame, two extended subsystems are developed: a velocity extended model and a flux extended model. Using these models, two HOSMOs are designed to estimate the disturbances in each subsystem. The HOSMO outputs are then used for disturbance rejection, resulting in two second-order systems with small bounded disturbances. Two TCs are subsequently implemented to achieve finite-time velocity and flux tracking of the LIM. The primary advantage of this strategy lies in its ability to reduce chattering through active disturbance rejection. Hardware-in-the-loop (HIL) experiments validate the effectiveness of the proposed TC-HOSMO scheme. Full article