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Composite demineralized bone matrix nanofiber scaffolds with hierarchical interconnected networks via eruptive inorganic catalytic decomposition for osteoporotic bone regeneration

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Journal of Materials Science & Technology 2024年第32期199卷 246-259页

作者： Sung Won Ko Joshua Lee Ji Yeon Lee Jeong Hwi Cho Sunny Lee Hak Su Jang Chan Hee Park Hyun Jin Tae Cheol Sang Kim Young Min Oh Department of Bionanosystem Engineering Jeonbuk National UniversityJeonjuRepublic of Korea Department of Bionanotechnology and Bioconvergence Engineering Graduate SchoolJeonbuk National UniversityJeonjuRepublic of Korea Department of Mechanical Design Engineering Graduate SchoolJeonbuk National UniversityJeonjuRepublic of Korea College of Veterinary Medicine and Bio-safety Research Institute Jeonbuk National UniversityIksanRepublic of Korea R&D Center CGBIO IncSeongnamRepublic of Korea Division of Mechanical Design Engineering Jeonbuk National UniversityJeonjuRepublic of Korea Department of Neurosurgery Research Institute of Clinical MedicineJeonbuk National University MedicalSchool and HospitalJeonjuRepublic of Korea

demineralized bone matrix(dBM)is one of the standard biomaterials used to fill surgical bone defects in general orthopedic ***,current dBM products come in the form of powder or viscous solutions that fail to mimic the natural hierarchical structure of bone while also using large amounts of valuable *** overcome this,compact fibrous dBM/polymer(fdBM)composites were prepared via ***,by exploiting the catalytic decomposition of hydrogen peroxide,oxygen pockets are formed in the scaffold imparting it with a hierarchical porous structure similar to bone(Op-fdBM).These pockets created by bubbles of oxygen help give the scaffold a mechanically stable shape while the incorporated dBM supports cell adhesion and *** vivo evaluations reveal that fdBM increased bone volume by 41.7%while Op-fdBM increased bone volume by 68.6%.Significant increases in regenerated bone volume with the use of minimal amounts of dBM in fiber form go to show the great potential of this work in the field of bone regeneration.

关键词： demineralized bone matrix Hierarchical networks Catalytic decomposition Bone regeneration

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Malware detection for Android TV

SSRN

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SSrN 2024年

作者： Ozogur, Gokhan Erturk, Mehmet Ali Aydin, Muhammed Ali R&D Software Design Department Arcelik A.S. Istanbul Turkey Department of Computer Engineering Istanbul University Istanbul Turkey Department of Computer Engineering Istanbul University-Cerrahpasa Istanbul Turkey

Security of Android applications is a well-studied area in the literature but it is very limited for other types of devices like Android TVs. Android TVs are growing in popularity with advances in integrated services and gaming features, and are also attracting the attention of attackers. Although there is extensive literature on Android security for mobile devices, the literature on malware detection for Android TV devices is quite limited. In this study, we collected Android TV applications from markets and injected malicious payload into some of the benign applications to have Android TV malware which is hard to find in the market. We extracted n-grams from *** and binary source (***) files in Android TV application packages, and obtained 1000 features using the TF-IdF method. We publicly shared these features and class (benign or malicious) labels of the Android TV applications in spreadsheet format as a dataset for future studies. Also, we implemented 3 separate classification models using Extreme Gradient Boosting (XGBoost), Neural Network (NN) and Support Vector Machine (SVM) methods to compare their performance on this dataset for malware detection. We observed that XGBoost model perfomed better than NN and SVM models. XGBoost model classifies a TV application as malicious or benign in average of 0.0102 milliseconds with 97.31% F1-score and 94.62% MCC scores. © 2024, The Authors. All rights reserved.

关键词： Android (operating system)

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A New Method for Fast and Accurate Calculation of Saturation Curves for Large Synchronous Generators

A New Method for Fast and Accurate Calculation of Saturation...

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Electrical Machines and drives (ICEMd), International Conference on

作者： Farshad Kiani Hamed Tahanian Electromagnetic Design Specialist R&D Department MAPNA Generator Engineering and Manufacturing Co. (PARS) Karaj Iran Electromagnetic Design Group R&D Department MAPNA Generator Engineering and Manufacturing Co. (PARS) Karaj Iran

ISBN: (数字)9798331507510

ISBN: (纸本)9798331507527

Synchronous generators are the main electric machine in steam, gas and combined cycle power plants. Various methods have been proposed for the design and analysis of large synchronous generators, although these methods are often not very accurate and/or fast. This paper introduces a fast method, which calculates the saturation curves of large synchronous generators from a single static Finite Element (FE) simulation. Open circuit, short circuit and full load field currents are calculated using the proposed method. Test results are compared with output of the developed method. Comparison between test and analytical results show low error and high precision which is acceptable in tendering and design stage of turbogenerators.

关键词： reactive power Accuracy Turbogenerators Synchronous generators Generators Finite element analysis Power generation design optimization

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Strength analysis of the bushing system supporting set for a medium power turbo-generator using the multiphysics method

Strength analysis of the bushing system supporting set for a...

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Electrical Machines and drives (ICEMd), International Conference on

作者： Saeed rostami Peyman Shoreshi Mohsen Nikfar Mechanical Design Specialist R&D Department MAPNA Generator Engineering and Manufacturing Co. (PARS) Karaj Iran Mechanical Design Group R&D Department MAPNA Generator Engineering and Manufacturing Co. (PARS) Karaj Iran

ISBN: (数字)9798331507510

ISBN: (纸本)9798331507527

In this paper, a comprehensive stress analysis of the bushing support system for a medium-power turbo-generator is presented, using the multiphysics approach. For evaluation of the system response, the finite element method (FEM) is utilized for three types of loads: electromagnetic, thermal, and mechanical. The electromagnetic and thermal loads are computed for both rated and fault conditions. In addition, mechanical loads, including bolt pre-tension, weight, and seismic acceleration are applied. All various loads are combined through a standard method, and the subsequent stress distribution is analyzed for all components based on the appropriate stress criteria. Since the bushings are used in transferring electrical currents from the stator windings to the casing outlet, allowable creepage and air electrical distances, by standard regulations, should be observed. Consequently, the support structures are required to be constructed from non-conductive materials or designed to meet the specified minimum distances. In this study, EPGM composite material is selected for the supports due to its non-conductive properties and ability to withstand the worst conditions. The structural design of supports is optimized to ensure their durability under the worst conditions. Finally, the safety factors for all components are calculated and then compared to the permissible limits.

关键词： Stator windings Insulators regulation Safety Finite element analysis Thermal analysis Thermal loading Electromagnetics Stress Standards

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Frame and Stator Core Vibration Analysis of a Medium Power Generator through Finite Element Method

Frame and Stator Core Vibration Analysis of a Medium Power G...

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Electrical Machines and drives (ICEMd), International Conference on

作者： Masoud Shahparasti Mojtaba dehghani Mohsen Nikfar Mechanical Design Specialist R&D Department MAPNA Generator Engineering and Manufacturing Co. (PARS) Karaj Iran Mechanical Design Group R&D Department MAPNA Generator Engineering and Manufacturing Co. (PARS) Karaj Iran

ISBN: (数字)9798331507510

ISBN: (纸本)9798331507527

This research employs a numerical method to extract dynamic characteristics of the frame and stator core of a medium power turbo-generator and investigates their behavior under rotor unbalance and 4-nodal electromagnetic forces. Harmonic analysis is conducted to evaluate the forced vibration response, and modal analysis is utilized to determine the natural frequencies and mode shapes of the frame and stator core *** laminated stacked core is simplified and modeled as an equivalent cylindrical core. The Foundation is excluded from modeling due to its high mass relative to the generator, and the generator interface with the concrete below is considered as a fixed boundary *** reveal that modifications applied to springs, ribs, and core clamping components cause the main natural frequencies of the stator core and frame, as well as local mode shapes of the pedestal region, to be located away from excitation frequencies. The harmonic analysis demonstrates that the dynamic response ratio of frame-to-core (it means core-to-frame vibration transmission) is less than 1, and the bearing is acceptable according to ISO 20816-2. This research contributes to understanding of generator dynamics and provides valuable insights for improving design, optimizing structural performance, and enhancing the reliability of generators.

关键词： Vibrations Stator cores Shape Modal analysis rotors Harmonic analysis reliability engineering Generators Springs ribs

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Total Stator Copper Loss Calculation in large Synchronous Generators with Hybrid Modeling

Total Stator Copper Loss Calculation in large Synchronous Ge...

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Electrical Machines and drives (ICEMd), International Conference on

作者： AmirAbbas Vahaj Hamed Tahanian Electromagnetic Design Specialist R&D Department MAPNA Generator Engineering and Manufacturing Co. (PARS) Karaj Iran Electromagnetic Design Group R&D Department MAPNA Generator Engineering and Manufacturing Co. (PARS) Karaj Iran

ISBN: (数字)9798331507510

ISBN: (纸本)9798331507527

This paper calculates AC losses in the stator winding of large generators. In large generators, copper loss in the stator winding consists of conventional copper loss known as dC copper loss, AC copper loss which is due to the AC current passing through the conductors and causing eddy current in the conductors, and additional loss called Circulating Current (CC) loss which caused by using parallel strands in the coil of generators to diminish eddy current loss in stator winding of large generators. The exact calculation of AC and CC loss beside dC loss is crucial for the thermal analysis of the machine because they are determinative and considerable. Hence in this paper, an analytical model is presented to calculate dC, AC and CC loss simultaneously. To feed the inputs of the presented model, Finite Element Model (FEM) is used which creates a hybrid model for finding dC, AC and CC losses. In the end presented model was validated by FEM. Then it is used to calculate the stator winding loss of a 120MW synchronous generator.

关键词： Analytical models Stator windings Conductors Synchronous generators Generators Finite element analysis Thermal analysis Copper Integrated circuit modeling Eddy currents

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A Finite Element Based design Optimization Tool for Large Synchronous Generators

A Finite Element Based Design Optimization Tool for Large Sy...

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Electrical Machines and drives (ICEMd), International Conference on

ISBN: (数字)9798331507510

ISBN: (纸本)9798331507527

The paper seeks the development of a design optimization tool package for turbogenerators based on the Finite Element Method (FEM). The package comprises of a FEM simulation software and a numerical computing program for secondary user-defined post-processing calculations. In this paper the Ansys Electronics desktop is chosen as the FEM package due to its fast and precise solutions and scripting options, and MATLAB was our post-processing application. Since the package was supposed to be used as the electromagnetic design section of a multi-physics design tool for turbogenerators, it had to be as fast as possible. Some properties of synchronous generators, like machine’s performance under sustained short circuit and full load conditions, are usually obtained from time consuming transient calculations. Such calculations can be replaced with single magneto-static simulations accompanied by some post-processing and parallel processing.

关键词： Accuracy Magnetostatics Turbogenerators Parallel processing software Synchronous generators Finite element analysis Transient analysis Power generation design optimization

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development of a Lamped Parameter Model for flow distribution and windage analysis in electric machines

Development of a Lamped Parameter Model for flow distributio...

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Electrical Machines and drives (ICEMd), International Conference on

作者： Ali Zadehkafi Ehsan Mohammadian Mohammad Bagher Mahaki Thermal Design Specialist R&D Department MAPNA Generator Engineering and Manufacturing Co. (PARS) Karaj Iran Thermal Design Group R&D Department MAPNA Generator Engineering and Manufacturing Co. (PARS) Karaj Iran

ISBN: (数字)9798331507510

ISBN: (纸本)9798331507527

In this article, an LPM (Lumped Parameter Model) method has been developed to determine windage losses and the flow distribution inside electrical machines. This method involves constructing a comprehensive network of hydraulic resistances representing various parts of the machine. By solving the governing equations over this network, the pressure and flow distribution within the machine can be accurately determined. The proposed method simplifies the complex task of modeling fluid dynamics within electric machines by breaking down the problem into manageable parts, each represented by hydraulic resistances. The results obtained from this method demonstrate a high degree of accuracy when compared to conventional CFd (Computational Fluid dynamics) simulations. This approach not only reduces computational time but also provides valuable insights for the design and optimization of cooling systems in electrical machines. The enhanced understanding of flow patterns and windage losses allows for more efficient design modifications, ultimately improving the performance and longevity of these machines. The satisfactory accuracy of the presented method makes it a viable alternative for preliminary design assessments and optimization studies in the field of electrical machine design.

关键词： Accuracy Electric machines Cooling Computational modeling Computational fluid dynamics Hydraulic systems Mathematical models software Thermal analysis Optimization

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Multiphysics Analysis of the End winding Support System for a Medium Power Air-cooled Turbo-generator

Multiphysics Analysis of the End winding Support System for ...

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Electrical Machines and drives (ICEMd), International Conference on

作者： Behzad Bahrami Joo Mojtaba dehghani Mohsen Nikfar Mechanical Design Specialist R&D Department MAPNA Generator Engineering and Manufacturing Co. (PARS) Karaj Iran Mechanical Design Group R&D Department MAPNA Generator Engineering and Manufacturing Co. (PARS) Karaj Iran

ISBN: (数字)9798331507510

ISBN: (纸本)9798331507527

This paper provides a comprehensive multiphysics analysis of the stator end winding support system for a medium power air-cooled turbo-generator. The main objective is to design the most accurate and reliable components in the final winding system that will be subjected to the highest possible stresses. For this reason, the implementation of FEM methodology and simulations in a multiphysics environment are used in the analysis of the impact of temperature gradients, electromagnetic forces, and mechanical vibrations. A variety of design criteria are employed to investigate the durability and functionality of the end winding system in diverse force environments. The findings of this research provide the essential data to extend the operational lifespan of the air-cooled turbo-generator and reinforce the safety margin of its critical components.

关键词： Vibrations Windings Stator windings Electromagnetic forces Thermal force reliability engineering Thermal analysis Safety Thermal loading Stress

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Electromagnetic Forces on the End Windings and Terminal Connections of Large Electric Machines: Calculations, Considerations, and Capabilities for Stress Analysis

Electromagnetic Forces on the End Windings and Terminal Conn...

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Electrical Machines and drives (ICEMd), International Conference on

作者： Hamed Tahanian AmirAbbas Vahaj Farshad Kiani Electromagnetic Design Group R&D Department MAPNA Generator Engineering and Manufacturing Co. (PARS) Karaj Iran Electromagnetic Design Specialist R&D Department MAPNA Generator Engineering and Manufacturing Co. (PARS) Karaj Iran

ISBN: (数字)9798331507510

ISBN: (纸本)9798331507527

End windings are the integral part of electrical machines, which should be mechanically supported through appropriate measures. The determination of electromagnetic force distribution under the worst-case scenario is a prerequisite for conducting the mechanical stress analysis. This paper presents a detailed description of a proper approach for this kind of force calculation. Large turbo-generators have been targeted for this purpose, although this method can be extended to other machines. 2d transient FEA has been employed to obtain the required information for the worst-case scenario, i.e. the sudden three-phase short circuit at the machine terminals. These data, including the stator currents, field current, and rotor position, are taken as the inputs of 3d magnetostatic models, which provide the adaptive meshing capability. The force calculation has been repeated for different setups to investigate the amount of details that should be taken into account while creating the FE models. It reveals that the active (e.g. cores) and inactive (e.g. support brackets) surrounding magnetic materials as well as the rotor current and position are the most influential factors on both the distribution and magnitude of the end winding forces. Furthermore, due to conceptual and geometrical differences, both the drive and non-drive ends of the machine have been analyzed. Therefore, the forces on the circuit rings and terminal connections could also be evaluated. The geometry of the terminal connections has been modified according to these results to achieve an acceptable force distribution.

关键词： Solid modeling Three-dimensional displays Magnetostatics Magnetic cores Magnetomechanical effects Force Windings rotors Integrated circuit modeling Transient analysis

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