Behrooz Majidi, Jafar Milimonfared and Kaveh Malekian
To optimize the performance of direct torque‐controlled interior permanent magnet synchronous motor drives, the purpose of this paper is to modify the constraints and strategies…
Abstract
Purpose
To optimize the performance of direct torque‐controlled interior permanent magnet synchronous motor drives, the purpose of this paper is to modify the constraints and strategies of such a control while accounting for magnetic saturation.
Design/methodology/approach
The machine model used to investigate the proposed method is the conventional two‐axis machine model, which is modified to include magnetic saturation in the quadrature axis. With the consideration of magnetic saturation, all optimal strategies, which correspond to the maximum torque per ampere and field weakening strategies, and motor‐inverter limitations are derived in T−|ψs| plane to apply in the direct torque control (DTC) method. Such strategies which take magnetic saturation into account and determine the optimal torque and flux commands are derived and implemented in DTC method.
Findings
Using the modified strategies ensures that the machine capacity is applied as much as possible. Simulation results emphasize the applicability and effectiveness of the proposed control process.
Research limitations/implications
In order to use the proposed method, it is necessary to define quadrature‐axis inductance as a function of quadrature‐axis current. Since, in this method, a simplified function is applied, it is not required to know exact magnetic behavior of motor and this simplified function can be easily obtained using finite element softwares.
Practical implications
Using the proposed method in practice results in better dynamic operation as well as maximal usage of the motor capacity.
Originality/value
This paper deals with consideration of magnetic saturation in DTC method which is not done in pervious works.
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Behnam Ameri, Fathollah Taheri-Behrooz and Mehdi Ghahari
The field of medical technology is constantly evolving, leading to improvements in implantation techniques that offer innovative solutions for treating bone tissue defects. The…
Abstract
Purpose
The field of medical technology is constantly evolving, leading to improvements in implantation techniques that offer innovative solutions for treating bone tissue defects. The purpose of this study is to investigate the integration of nano-silica into ceramic scaffolds to enhance the mechanical strength of Hydroxyapatite structures.
Design/methodology/approach
Using the design of experiment methodology, 13 distinct ceramic pastes, each optimized for specific mechanical characteristics, are formulated. Rheological testing is performed to ensure suitability for 3D printing, and the pastes are evaluated using techniques such as scanning electron microscopy and energy dispersive X-ray spectroscopy. The definitive screening design optimizer is used to determine an ideal material combination based on factors like extrudability, printability, strength and biocompatibility.
Findings
Scaffolds with the optimized HA/SiO2 composition are fabricated and tested for compression strength, achieving 7.8 MPa.
Originality/value
The research endeavors detailed within this study represent a notable advancement in the augmentation of ceramic scaffold properties tailored for bone tissue engineering applications, particularly focusing on their suitability for integration within load-bearing structures. A particular emphasis is placed on the enhancement of printability, thereby facilitating streamlined fabrication processes.
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Hamid Mattiello, Omid Alijani, Mohammad Rahimi Moghaddam and Behnam Ameri
This study explores evolving tourist preferences post-COVID-19, focusing on the growing demand for sustainable tourism. Using the X.0 wave/tomorrow age theory when X.0 = 5.0, it…
Abstract
Purpose
This study explores evolving tourist preferences post-COVID-19, focusing on the growing demand for sustainable tourism. Using the X.0 wave/tomorrow age theory when X.0 = 5.0, it identifies transformative trends influencing the tourism industry's adaptation to new sustainability expectations.
Design/methodology/approach
A mixed-methods approach combines extensive surveys and interviews with diverse tourist profiles to examine behaviors and preferences. The seven pillars of sustainability (7PS) model frames the analysis.
Findings
Tourism is shifting toward sustainable practices, emphasizing cultural differences, environmental stewardship, social engagement, economic resilience, technological infrastructure, educational methods and political supports. The integration of X.0 wave theory with SME 5.0 concepts highlights the importance of responsible tourism aligned with evolving tourist expectations.
Originality/value
This study pioneers the application of the X.0 wave/tomorrow age theory to tourism, offering a novel framework for sustainable practices. It provides insights for making tourism resilient, ecologically sound and socially responsible, meeting post-pandemic visitor demands.
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Behnam Ameri, Fathollah Taheri-Behrooz, Hamid Reza Majidi and Mohammad Reza Mohammad Aliha
The main aim of this study is to investigate the mixed-mode I/II failure and the cracking manner of three-dimensional (3D)-printed components made by the fused deposition modeling…
Abstract
Purpose
The main aim of this study is to investigate the mixed-mode I/II failure and the cracking manner of three-dimensional (3D)-printed components made by the fused deposition modeling technique in an experimental and theoretical manner.
Design/methodology/approach
Acrylonitrile butadiene styrene (ABS) material and a modified printing method (that increases the adhesion and integrity between the layers and strands) are used for manufacturing the semicircular bending (SCB) test samples. In addition to precracking, the effect of additional stress concentration on the stress field is studied by introducing three small holes to the SCB fracture samples. The critical mixed-mode I/II failure loads obtained from the experiments are predicted using different stress/strain-based fracture theories, including maximum tangential stress (MTS), maximum tangential strain (MTSN), generalized form of MTS and MTSN and combination of them with equivalent material concept (EMC). The effects of plastic deformation, as well as the structural stress concentration, are considered for a more realistic prediction of mixed-mode fracture load.
Findings
The stress-based criteria are more suitable than the strain-based theories. Among the investigated fracture models, the EMC–generalized maximum tangential stress theory provided the best agreement with the experimental results obtained from 3D-printed SCB tests.
Originality/value
The influences of stress risers and applicability of different failure theories in cracked layered 3D-printed parts are studied on the fracture behavior of tested specimens under mixed-mode I/II.