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The properties of SiC and diamond make them attractive materials for MEMS and sensor devices. We innovated specific laser ablation techniques to fabricate membranes and cantilevers made of SiC or nano-(micro-) crystalline diamond films grown on Si/SiO2 substrates by microwave chemical vapour deposition (MWCVD). We started research to generate surface moulds to grow corrugated diamond films for membranes and cantilevers. A software tool was developed to support the design of micromechanical cantilevers. We can measure deformation and resonant frequency of diamond cantilevers and identify the global mechanical properties. A benchmark against finite element simulations enables an inverse identification of the specific system parameters and simplifies the characterization procedure.
Grid-scale electrical energy storage (EES) is a key component in cost-effective transition scenarios to renewable energy sources. The requirement of scalability favors EES approaches such as pumped-storage hydroelectricity (PSH) or compressed-air energy storage (CAES), which utilize the cheap and abundant storage materials water and air, respectively. To overcome the site restriction and low volumetric energy densities attributed to PSH and CAES, liquid-air energy storage (LAES) has been devised; however, it suffers from a rather small round-trip efficiency (RTE) and challenging storage conditions. Aiming to overcome these drawbacks, a novel system for EES is developed using solidified air (i.e., clathrate hydrate of air) as the storable phase of air. A reference plant for solidified-air energy storage (SAES) is conceptualized and modeled thermodynamically using the software CoolProp for water and air as well as empirical data and first-order approximations for the solidified air (SA). The reference plant exhibits a RTE of 52% and a volumetric storage density of 47 kWh per m3 of SA. While this energy density relates to only one half of that in LAES plants, the modeled RTE of SAES is comparable already. Since improved thermal management and the use of thermodynamic promoters can further increase the RTEs in SAES, the technical potential of SAES is in place already. Yet, for a successful implementation of the concept - in addition to economic aspects - questions regarding the stability of SA must be first clarified and challenges related to the processing of SA resolved.
Violation-mitigation-based method for PV hosting capacity quantification in low voltage grids
(2022)
Hosting capacity knowledge is of great importance for distribution utilities to assess the amount of PV capacity possible to accommodate without troubling the operation of the grid. In this paper, a novel method to quantify the hosting capacity of low voltage grids is presented. The method starts considering a state of fully exploited building rooftop solar potential. A downward process is proposed - from the starting state with expected violations on the grid operation to a state with no violations. In this process, the installed PV capacity is progressively reduced. The reductions are made sequentially and selectively aiming to mitigate specific violations: nodes overvoltage, lines overcurrent and transformer overloading. Evaluated on real data of fourteen low voltage grids from Austria, the method proposed exhibits benefits in terms of higher hosting capacities and lower computational costs compared to stochastic methods. Furthermore, it also quantifies hosting capacity expansions achievable by overcoming the effect of the violations. The usage of a potential different from solar rooftops is also presented, demonstrating that a user-defined potential allows to quantify the hosting capacity in a more general setting with the method proposed.
The impact of global warming and climate change has forced countries to introduce strict policies and decarbonization goals toward sustainable development. To achieve the decarbonization of the economy, a substantial increase of renewable energy sources is required to meed energy demand and to transition away from fossil fuels. However, renewables are sensitive to environmental conditions, which may lead to imbalances between energy supply and demand. Battery energy storage systems are gaining more attention for balancing energy systems in existing grid networks at various levels such as bulk power management, transmission and distribution, and for end-users. Integrating battery energy storage systems with renewables can also solve reliability issues related to transient energy production and be used as a buffer source for electrical vehicle fast charging. Despite these advantages, batteries are still expensive and typically built for a single application – either for an energy- or power-dense application – which limits economic feasibility and flexibility. This paper presents a theoretical approach of a hybrid energy storage system that utilizes both energy- and power-dense batteries serving multiple grid applications. The proposed system will employ second use electrical vehicle batteries in order to maximise the potential of battery waste. The approach is based on a survey of battery modelling techniques and control methods. It was found that equivalent circuit models as well as unified control methods are best suited for modelling hybrid energy storages for grid applications. This approach for hybrid modelling is intended to help accelerate the renewable energy transition by providing reliable energy storage.
In previous studies of linear rotary systems with active magnetic bearings, parametric excitation was introduced as an open-loop control strategy. The parametric excitation was realized by a periodic, in-phase variation of the bearing stiffness. At the difference between two of the eigenfrequencies of the system, a stabilizing effect, called anti-resonance, was found numerically and validated in experiments. In this work, preliminary results of further exploration of the parametric excitation are shared. A Jeffcott rotor with two active magnetic bearings and a disk is investigated. Using Floquet theory, a deeper insight into the dynamic behavior of the system is obtained. Aiming at a further increase of stability, a phase difference between excitation terms is introduced.
Deep etched structures in GaAs with high aspect ratio have promising applications in optoelectronics and MEMS devices. The key factors in their fabrication process are the choosing of proper mask material and etching conditions which results in high selectivity and an anisotropic etch profile with smooth sidewalls. In this work, we studied several types of mask materials (Al, Ni, Cr, SiO2) for deep reactive ion etching of GaAs using inductively coupled plasma system. Thus, several sets of experiments were performed with varying gas mixture, pressure and ICP/RF power. As a result, we find optimized conditions and minimal thickness of mask material for achieving deep etched (>140 m) GaAs structures.
Bachground: Worldwide, more than 79.5 million people are forcibly displaced, including a significant number of migrant and refugee families with children. Migration and refugeedom affect these families in different dimensions, such as mental, physical and spiritual health. Identifying family needs and enhancing parenting skills can improve family cohesion and health, as well as smooth integration into the host country. This review is part of the Erasmus+ funded project- IENE 8 (Intercultural Education for Nurses in Europe) aiming at empowering migrant and refugee families regarding parenting skills.
Methods: This was a scoping review of literature. The IENE 8 partner countries (Cyprus, Germany, Greece, Italy, Romania, and United Kingdom) searched for peer reviewed papers, grey literature and mass media reports at international, European and national level. The time period for the search of scientific and grey literature was between2013-2018, and for mass media, it was between 2016 and 2018. Results: 124 relevant sources were identified. They included 33 Peer reviewed papers, 47 Grey literature documents and 44 mass media reports. This revealed the importance of understanding the needs of migrant families with children. Conclusion: It is evident from the literature that there is a need to support refugee parents to adjust their existing skill and to empower them to develop new ones. Healthcare and social services professionals have an essential role in improving the refugees' parenting skills. This can be done by developing and implementing family-centered and culturally-sensitive intervention programs.
Diversiteit
(2022)
Gesundheitsdienstleister kommen täglich mit Vielfalt in Berührung. Aus diesem Grund ist es ein wichtiges Thema in der Berufsausbildung. Das Bewusstsein für Unterschiede im soziokulturellen Hintergrund geht Hand in Hand mit dem Finden von Gemeinsamkeiten.
Inhalt
In dieser Ausgabe der ZorgBasics-Reihe steht Vielfalt in all ihren Facetten im Mittelpunkt. Aus theoretischen Rahmen, persönlichen Lebensgeschichten und Beispielen aus der Gesundheitspraxis wird das Thema Vielfalt vertieft. Weil Vielfalt auch viel mit der eigenen Persönlichkeit zu tun hat, werden dem Leser auch reflektierende Fragen gestellt.
Charakterisieren
• Dem Studierenden werden praktische Werkzeuge an die Hand gegeben, mit denen er Vielfalt auf unterschiedliche Weise betrachten kann.
• Das Buch diskutiert Vielfalt im weitesten Sinne des Wortes und macht das Thema mit Hilfe von Reflexionsübungen aufschlussreich.
• Gedacht für alle in der HGZO gibt es aber auch konkrete Beispiele aus der Pflege- und Ergotherapie.
Neu
Für die dritte Auflage wurde der Inhalt gründlich überarbeitet. Zeitgenössische Entwicklungen wie sexuelle Orientierung und Geschlechtsidentität, Black Lives Matter und die Corona-Pandemie wurden einbezogen. Die Literatur wurde aktualisiert und viele Fälle wurden erneuert. Die Theorien und Modelle wurden um Superdiversität und Intersektionalität erweitert. Darüber hinaus wird auf eine positive Gesundheit und die Suche nach Gemeinsamkeiten und Überbrückungsunterschieden geachtet.
Zielgruppe
Geschrieben für Studenten, die einen Kurs im Gesundheitswesen und Fachleute im Gesundheitswesen absolvieren.
The properties of diamond make it an attractive material for MEMS and sensor devices. We present the feasibility to fabricate membranes and cantilevers made of nano-(micro-) crystalline diamond films grown on Si/SiO2 substrates using microwave chemical vapour deposition (MWCVD). The patterning of micromechanical structures was performed by a combined process of femtosecond laser ablation and wet etching. We designed cantilever structures with varying lengths and widths (25, 50, 100, 200 and 300 μm). The cantilevers were made in a symmetric left- and right-hand configuration. An additional laser treatment was used to modify the mechanical properties of the left-hand cantilever. The deflection of the laser-treated, and non-treated sections was measured. The global mechanical system properties were simulated and corresponded with high accuracy to the measured results of deflection.
Increasing electric vehicle penetration leads to undesirable peaks in power if no proper coordination in charging is implemented. We tested the feasibility of electric vehicles acting as flexible demands responding to power signals to minimize the system peaks. The proposed hierarchical autonomous demand side management algorithm is formulated as an optimal power tracking problem. The distribution grid operator determines a power signal for filling the valleys in the non-electric vehicle load profile using the electric vehicle demand flexibility and sends it to all electric vehicle controllers. After receiving the control signal, each electric vehicle controller re-scales it to the expected individual electric vehicle energy demand and determines the optimal charging schedule to track the re-scaled signal. No information concerning the electric vehicles are reported back to the utility, hence the approach can be implemented using unidirectional communication with reduced infrastructural requirements. The achieved results show that the optimal power tracking approach has the potential to eliminate additional peak demands induced by electric vehicle charging and performs comparably to its central implementation. The reduced complexity and computational overhead permits also convenient deployment in practice.