Branlard, E. ., & Geisler, J. . (2022). A symbolic framework to obtain mid-fidelity models of flexible multibody systems with application to horizontal-axis wind turbines. Wind Energy Science, 7, 2351–2371. http://doi.org/10.5194/wes-7-2351-2022
Abstract
The article presents a symbolic framework (also called computer algebra program) that is used to obtain, in symbolic mathematical form, the linear and nonlinear equations of motion of a mid-fidelity multibody system including rigid and flexible bodies. Our approach is based on Kane's method and a nonlinear shape function representation for flexible bodies. The shape function approach does not represent the state of the art for flexible multibody dynamics but is an effective trade-off to obtain mid-fidelity models with few degrees of freedom, taking advantage of the separation of space and time. The method yields compact symbolic equations of motion with implicit account of the constraints. The general and automatic framework facilitates the creation and manipulation of models with various levels of complexity by adding or removing degrees of freedom. The symbolic treatment allows for analytical gradients and linearized equations of motion. The linear and nonlinear equations can be exported to Python code or dedicated software. There are multiple applications, such as time domain simulation, stability analyses, frequency domain analyses, advanced controller design, state observers, and digital twins. In this article, we describe the method we used to systematically generate the equations of motion of multibody systems and present the implementation of the framework using the Python package SymPy. We apply the framework to generate illustrative land-based and offshore wind turbine models. We compare our results with OpenFAST simulations and discuss the advantages and limitations of the method. The Python implementation is provided as an open-source project.
Labes, A. ., Koopmann, I. K., Möller, S. ., Elle, C. ., Hindersin, S. ., Kramer, A. ., & Labes, A. . (2022). Optimization of Astaxanthin Recovery in the Downstream Process of Haematococcus pluvialis. Foods. http://doi.org/10.3390/foods11091352
Selaskowski, B. . (2022). Smartphone-assisted psychoeducation in adult attention-deficit/hyperactivity disorder: A randomized controlled trial. Psychiatry Research, 317, 114802. http://doi.org/https://doi.org/10.1016/j.psychres.2022.114802
Abstract
Psychoeducation is generally recommended in the treatment of adult Attention-Deficit/Hyperactivity Disorder (ADHD), but only few studies have systematically assessed the effects of structured clinical psychoeducation. Moreover, although a considerable number of psychoeducational mobile applications exist, none have provided scientific evidence for their effectiveness or safety. Therefore, the present randomized controlled trial investigated a newly developed, free-to-use psychoeducation app for adults with ADHD as a support to a clinical psychoeducation group. 236 adults with ADHD were contacted for study participation, of whom 60 were finally randomized to a psychoeducation group supported either by our developed smartphone app (n = 30) or by traditional pen-and-paper brochures (n = 30). Psychoeducation treatments were conducted in groups of 10, with 8 weekly one-hour sessions between March 2019 and November 2020. Observer-rated ADHD symptom severity (IDA-R interview) was examined as the primary outcome parameter before and after treatment. Across both interventions, ADHD core symptoms were significantly reduced. Notably, the smartphone-assisted psychoeducation was significantly more effective in improving inattention and impulsivity and led to higher homework compliance than the brochure-assisted psychoeducation. No adverse events were reported.
Chen, C. ., Witte, F. ., Tuschy, I. ., Kolditz, O. ., & Shao, H. . (2022). Parametric optimization and comparative study of an organic Rankine cycle power plant for two-phase geothermal sources. Energy, 123910. http://doi.org/https://doi.org/10.1016/j.energy.2022.123910
Abstract
For two-phase geothermal sources, Organic Rankine Cycle (ORC) based binary plant is often applied for power production. In this work, a network topology is designed with the open-source Thermal Engineering Systems in Python (TESPy) software to simulate the stationary operation of the ORC plant. With this topology, the performance of six different working fluids are compared. From the thermodynamic perspective, the gross and net power output are optimized respectively. Results show that R600 has the highest gross power output of 17.55 MW, while R245fa has the highest net power output of 12.93 MW. However, the turbine inlet temperatures for these two working fluids need to be designed at the upper theoretical limit. R245ca and R601a require the heat exchange rates of internal heat exchanger to be larger than 1.51 MW and 0.99 MW to satisfy the re-injection temperature limit, which are smaller than the R600 (6.7 MW) and R245fa (6.0 MW) cases. Besides, the working fluid with lower critical state is preferred for a geothermal source with smaller steam fraction to establish a stable ORC plant. The workflow for the ORC design and optimization in this work is generic, and can be further applied to thermo-economic investigation.
Berg, S.-H. ., & Mitra, J. . (2022). Good Tech and Social Good: Value Creation by Korean Social and High-Tech Oriented Start-Ups. Volume 8 Issue 1, 8(1), 29–45. Abgerufen von https://EconPapers.repec.org/RePEc:sae:jouent:v:8:y:2022:i:1:p:29-45
Abstract
Through an exploration of Korean high-tech social enterprises, we aim to identify and explore critically (a) how socially engaged, early stage, high technology firms combine social and economic objectives with which to scale up their ventures; and (b) how socially engaged firms seek entrepreneurial opportunity development, including the internationalisation process and the support of stake holding institutions to help scale up the value creation process. We highlight ‘people’, ‘organisations’ and the ‘environment’ dimensions, enabling an understanding of the drivers of socially entrepreneurial activity both from individual and societal perspectives. The analytical framework of our study is based on empirical data acquired from individual in-depth interviews, group interviews, active participatory observations and survey data from 2018 to 2021. We found that social motivation and objectives of the entrepreneurs are equally strong drivers and that they are the principal factors for the scaling up process. The motivation is strengthened by the proactive role of government initiatives which also attract other key stakeholders in the growth process. A combination of digital technology with a high degree of social motivation of the entrepreneurs tends to lead to the development of international market opportunities and attract the interests of international foundations.
Ivannikov, V. ., Thomsen, F. ., Ebel, T. ., & Willumeit-Römer, R. . (2022). Coupling the discrete element method and solid state diffusion equations for modeling of metallic powders sintering. Computational Particle Mechanics. http://doi.org/https://doi.org/10.1007/s40571-022-00486-6
Irshad, M. ., Börstler, J. ., & Petersen, K. . (2022). Supporting refactoring of BDD specifications—An empirical study. Information and Software Technology, 141, 106717.