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The production of liquid-gas dispersions places high demands on the process technology, which requires knowledge of the bubble formation mechanisms, as well as the phase parameters of the media combinations used. To obtain the bubble sizes introduced to a flow not knowing the phase parameters, different process parameters are investigated. Their quality and applicability are evaluated. The results obtained make it possible to simplify long design processes of dispersion processes in manufacturing plants and to ensure the product quality of the products manufactured, by reducing waste.
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.
Arbeitspaket 3: Ausschöpfung des Innovationspotentials von smarten Technologien - FH Vorarlberg
(2022)
Hallo. Ich bin Lio.
(2022)
Von Assistenzrobotern im Pflegebereich erhofft man sich Unterstützung in vielfacher Weise: Sie sollen zur Erleichterung für das Pflegepersonal führen (z.B. durch Handreichung von Gegenständen), mehr Sicherheit bringen (z.B. indem sie Nachschauen, sobald Auffälliges registriert wird) und zu einem gesunden Altern (z.B. körperliche Aktivierung) und zu mehr Teilhabe (z.B. psychosoziale Aktivierung) beitragen. Ihre Funktionen versprechen daher einerseits Assistenz für Pflege- und Betreuungspersonal (z.B. Transport- und Serviceaufgaben) und andererseits soziale Assistenz für Senior:innen in Pflegesituationen (z.B. Unterhaltung, Aktivierung).
In dem Projekt PUR (Pflegeunterstützende Robotik) wurde der Roboter Lio der Firma F&P Robotics AG über einen Zeitraum von 22 Monaten in Wohnbereichen in zwei Pflegeeinrichtungen in Konstanz und Schaffhausen getestet und situationsangepasst weiterentwickelt. Mit Unterstützung des Personals und der Bewohner:innen vor Ort wurde Lio anhand der Kriterien Usability, User Experience, Akzeptanz sowie seinen Nutzen für die Organisation evaluiert. Neben den Befragungen der Akteur:innen in den beiden Einrichtungen erfolgte eine systematische Erfassung und Analyse von Informationen und Daten anhand von Logfiles und Dokumenten in welchen Nutzungsdauer und -häufigkeit sowie Fehlerraten erfasst wurden.
Es wurde deutlich, dass Lio sich noch hinsichtlich aller Kriterien verbessern muss um die hohen Erwartungen bezüglich einer wahrnehmbaren Entlastung des Pflegepersonals bei gleichzeitiger Aufrechterhaltung oder Verbesserung der Lebensqualität der Bewohner:innen erfüllen zu können. Als Schlüsselfunktion für eine optimierte Usability und User Experience wird die Bedienbarkeit über Sprache betrachtet. Zum einen aus Sicht der Pflege- und Betreuungskräfte die Lio z.B. in hektischen Situationen in der Nachtschicht schnell und einfach in seinem Autonomiemodus (z.B. Desinfizieren von Türen) unterbrechen müssen. Zum anderen aus Sicht der Bewohner:innen die ihn ansprechen, aber nicht verstanden werden, womit das aktivierende Potential, das in Lio steckt, nicht ausgeschöpft wird.
Eine routinemäßige Einbindung von Assistenzrobotern wie Lio in die Pflege- und Betreuungspraxis erfordert neben der Lösung von technischen Problemen (wie zuverlässige Navigation, Sprachinteraktion) auch geeignete Beteiligungsansätze der Akteuer:innen. Diese sind so zu gestalten, dass nicht nur die technikaffinen Personen abgeholt werden, sondern allen ein entsprechendes Angebot gemacht wird, den Umgang mit dem technischen System zu erproben und in der Kontrolle und Bedienung Sicherheit zu erlangen.
Die befragten Akteur:innen sehen eine Zukunft für Assistenzroboter sofern sie autonom, zuverlässig und jederzeit gut kontrollierbar funktionieren und stehen dem digitalen Transformationsprozess in der Pflege größtenteils sehr offen gegenüber.
Trotz der Relevanz von Partizipationsprozessen in Unternehmen und deren belegte Auswirkungen zeigt sich ein deutliches Ungleichgewicht zwischen der aufgezeigten Bedeutung von Beteiligungsprozessen und dem gleichzeitig geringen Umsetzungsstand in Betrieben. Deshalb soll geprüft werden, inwiefern sich die Erwartungen jüngerer Mitarbeiter:innen mit ihrer erlebten Arbeitsrealität decken. Dazu wurden 459 Personen (59,5% Frauen) im Alter zwischen 16 und 35 Jahren zu allgemeinen Partizipationsmöglichkeiten und zu flexiblen Arbeitsbedingungen befragt. Es zeigen sich signifikante Unterschiede in beiden Teilbereichen der Partizipation zwischen den Erwartungen der Arbeitnehmer:innen und deren erlebter Realität in den Unternehmen. Über Angleichung der betrieblichen Realitäten der Partizipation könnten Unternehmen und Mitarbeiter:innen auf verschiedenen Ebenen gewinnen.
Industrial demand side management has shown significant potential to increase the efficiency of industrial energy systems via flexibility management by model-driven optimization methods. We propose a grey-box model of an industrial food processing plant. The model relies on physical and process knowledge and mass and energy balances. The model parameters are estimated using a predictive error method. Optimization methods are applied to separately reduce the total energy consumption, total energy costs and the peak electricity demand of the plant. A viable potential for demand side management in the plant is identified by increasing the energy efficiency, shifting cooling power to low price periods or by peak load reduction.
A trend from centralized to decentralized production is emerging in the manufacturing domain leading to new and innovative approaches for long-established production methods. A technology supporting this trend is Cloud Manufacturing, which adapts technologies and concepts known from cloud computing to the manufacturing domain. A core aspect of Cloud Manufacturing is representing knowledge about manufacturing, e.g., machine capabilities, in a suitable form. This knowledge representation should be flexible and adaptable so that it fits across various manufacturing domains, but, at the same time, should also be specific and exhaustive. We identify three core capabilities that such a platform has to support, i.e., the product, the process and the production.We propose representing this knowledge in semantically specified knowledge graphs, essentially creating three through features interconnected ontologies each representing a facet of manufacturing. Finally, we present an exemplary implementation of a Cloud Manufacturing platform using this representation and its advantages.
Bubble column humidifiers (BCHs) are frequently used for the humidification of air in various water treatment applications. A potential but not yet profoundly investigated application of such devices is the treatment of oily wastewater. To evaluate this application, the accumulation of an oil-water emulsion using a BCH is experimentally analyzed. The amount of evaporating water vapor can be evaluated by measuring the humidity ratio of the outlet air. However, humidity measurements are difficult in close to saturated conditions, as the formation of liquid droplets on the sensor impacts the measurement accuracy. We use a heating section after the humidifier, such that no liquid droplets are formed on the sensor. This enables us a more accurate humidity measurement. Two batch measurement runs are conducted with (1) tap water and (2) an oil-water emulsion as the respective liquid phase. The humidity measurement in high humidity conditions is highly accurate with an error margin of below 3 % and can be used to predict the oil concentration of the remaining liquid during operation. The measured humidity ratio corresponds with the removed amount of water vapor for both tap water and the accumulation of an oil-water emulsion. Our measurements show that the residual water content
in the oil-water emulsion is below 4 %.
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.
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.
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.
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.
Der Forschungsbericht gibt Antworten auf folgende Forschungsfrage: "Wie gestalten sich die interkulturellen Lebenswelten im Jahre 2021 im Orden der Steyler Missionare in St. Gabriel?" Das Erkenntnisinteresse dieser Studie ist, wie eine Ordensgemeinschaft in der heutigen Zeit funktioniert. Wie die veränderten gesellschaftlichen Werte, Normen und Regeln sich auswirken und wie sich ein normaler Alltag für ein Ordensmitglied gestaltet. Was es heißt zu missionieren und welche Erfahrungen Steyler Missionare hinsichtlich eines gelingenden interkulturellen Zusammenlebens haben, werden in dieser Studie beleuchtet. Die Recherchen zum Forschungsstand ergaben, dass es kaum Studien zum Ordensleben aus sozialwissenschaftlicher Sicht gibt. Die Lebenswelten der Ordensmitglieder werden mit Hilfe des lebensweltorientierten Ansatzes nach Thiersch und der Bedürfnistheorie nach Obrecht theoretisch fundiert. Das Sampling erfolgte mittels eines qualitativen Stichprobenplans. Die Datenerhebung erfolgte im Juli 2021. Die Auswertung erfolgte inhaltsanalytisch nach Mayring. Die Steyler Missionare können als weltoffene Ordensgemeinschaft betrachtet werden, deren Handeln wesentlich von den unterschiedlichen Missionserfahrungen geprägt ist. Ordensstrukturen unterscheiden sich deutlich von Strukturen der übrigen Gesellschaft. Diese Strukturen haben eine positive Wirkung auf die Ordensmitglieder. Diese, als auch eine sinnstiftende und erfüllende Tätigkeit sowie ein gewisses Maß an Freizeit ist anscheinend das Rezept für ein zufriedenes Leben. Die Mission hat für den Orden einen zentralen Stellenwert. Integration, Rassismus und Kolonialismus sind permanente Herausforderungen auch im Zusammenleben und werden aus verschiedenen Perspektiven diskutiert. In der Ordensgemeinschaft hat es viele Veränderungen gegeben, die Auswirkungen von diesen und der Umgang hiermit werden beschrieben sowie ein Blick in die Zukunft gewagt.
Traditional power grids are mainly based on centralized power generation and subsequent distribution. The increasing penetration of distributed renewable energy sources and the growing number of electrical loads is creating difficulties in balancing supply and demand and threatens the secure and efficient operation of power grids. At the same time, households hold an increasing amount of flexibility, which can be exploited by demand-side management to decrease customer cost and support grid operation. Compared to the collection of individual flexibilities, aggregation reduces optimization complexity, protects households’ privacy, and lowers the communication effort. In mathematical terms, each flexibility is modeled by a set of power profiles, and the aggregated flexibility is modeled by the Minkowski sum of individual flexibilities. As the exact Minkowski sum calculation is generally computationally prohibitive, various approximations can be found in the literature. The main contribution of this paper is a comparative evaluation of several approximation algorithms in terms of novel quality criteria, computational complexity, and communication effort using realistic data. Furthermore, we investigate the dependence of selected comparison criteria on the time horizon length and on the number of households. Our results indicate that none of the algorithms perform satisfactorily in all categories. Hence, we provide guidelines on the application-dependent algorithm choice. Moreover, we demonstrate a major drawback of some inner approximations, namely that they may lead to situations in which not using the flexibility is impossible, which may be suboptimal in certain situations.
Bubble columns are recently used for the humidification of air in water treatment systems and fuel cells. They are well applicable due to their excellent heat and mass transfer and their low technical complexity. To design and operate such devices with high efficiency, the humidification process and the impact of the operating parameters need to be understood to a sufficient degree. To extend this knowledge, we use a refined and novel method to determine the volumetric air–liquid heat and mass transfer coefficients and the humidifier efficiency for various parametric settings. The volumetric transfer coefficients increase with both of the superficial air velocity and the liquid temperature. It is further shown that the decrease of vapor pressure with an increase of the salinity results in a corresponding decrease in the outlet humidity ratio. In contrast to previous studies, liquid heights smaller than 0.1 m are investigated and significant changes in the humidifier efficiency are seen in this range. We present the expected humidifier efficiency with respect to the superficial air velocity and the liquid height in an efficiency chart, such that optimal operating conditions can be determined. Based on this efficiency chart, recommendations for industrial applications as well as future scientific challenges are drawn.