Wind turbine drivetrains:State-of-the-art technologies and future development trends

This paper presents the state-of-the-art technologies and development trends of wind turbine drivetrains – the system that converts kinetic energy of the wind to electrical energy – in different stages of their life cycle: design, manufacturing, installation, operation, lifetime extension, decommissioning and recycling. Offshore development and digitalization are also a focal point in this study. Drivetrain in this context includes the whole power conversion system: main bearing, shafts, gearbox, generator and power converter. The main aim of this article is to review the drivetrain technology development as well as to identify future challenges and research gaps. The main challenges in drivetrain research identified in this paper include drivetrain dynamic responses in large or floating turbines, aerodynamic and farm control effects, use of rare-earth material in generators, improving reliability through prognostics, and use of advances in digitalization. These challenges illustrate the multidisciplinary aspect of wind turbine drivetrains, which emphasizes the need for more interdisciplinary research and collaboration

Investigation on the Effects of Structural Dynamics on Rolling Bearing Fault Diagnosis by Means of Multibody Simulation

The present study aims to combine the fields modal analysis and signal processing and to show the use of Frequency Response Function (FRF), as a vibration transfer path, in enhancing reliability and abilities of the next generation vibration-based rolling bearing condition monitoring (CM) systems in complex mechanical systems. In line with this purpose, the hereby-presented paper employs an appropriate numerical model, that is, Multibody Simulation (MBS) of a vehicle’s drivetrain as a manner for numerical modal and structural analyses. For this, first, the principles of vibration-based bearing fault detection are reviewed and presented. Following that, a summary of MBS modelling and validating strategies are given. Then, the validated MBS model is used as a case study for further investigations. The results can confirm existence of challenges in fault detection of rolling bearings, in particular in complex mechanical systems. In further discussions, the capability of FRFs in fault localization and determination of ideal sensor positions is discussed in some detail. Finally, concluding remarks and suggestions for future works are summarized

Prevention of Transcriptional γ-globin Gene Silencing by Inducing The Hereditary Persistence of Fetal Hemoglobin Point Mutation Using Chimeraplast-Mediated Gene Targeting

Objective Hemoglobin F (HbF) augmentation is considered a clinically beneficial phenomenon in β-hemoglobinopathies. Prevention of γ-globin gene silencing, inspired by the hereditary persistence of fetal hemoglobin, may be a suitable strategy to upregulate HbF expression in these patients. Therefore, our objective was to assess the potential feasibility of induced -117 G→A substitution in HBG promoter in prevention of transcriptional silencing of the γ-globin. Materials and Methods In this experimental study, human peripheral blood-derived hematopoietic stem cells (HSCs) and the K562 cell line were differentiated to erythroid cells. Erythroid maturation was examined using cell morphology parameters and flow cytometry analysis of CD235a expression. A synthesised chimeraplast was transfected to differentiating cells. The efficiency of chimeraplast delivery into target cells was assessed by flow cytometry. Restriction-fragment length polymorphism and DNA sequencing verified oligonucleotide-directed mutagenesis. Gene conversion frequency and globin genes expression was quantified through Allele specific-quantitaive polymerase chain reaction (AS-qPCR) and quantitative-PCR respectively. Results Increase in CD235a-expressing cells along with observations made for different stages of erythroid maturation confirmed erythroid differentiation in HSCs and K562 cells. γ to β-globin gene switching was estimated to be on days 18-21 of HSC differentiation. Flow cytometry analysis showed that more than 70% of erythroid progenitor cells (EPCs) were transfected with the chimeraplast. The highest gene conversion efficiency was 7.2 and 11.1% in EPCs and K562 cells respectively. The induced mutation led to a 1.97-fold decrease in β/γ-globin gene expression in transfected EPCs at the experimental end point (day 28) whereas, due to the absence of β-globin gene expression following K562 differentiation, this rate was not evaluable. Conclusion Our results suggest the effectiveness of chimeraplasty in induction of the mutation of interest in both EPCs and K562 cells. We also demonstrate that the single nucleotide promoter variant was able to significantly inhibit γ-globin gene silencing during erythroid differentiation