Interdisciplinary learning assignments: theory, practice, and assessment by students. Results from the Project LEENA: combining nutritional science and English through a new task culture

Im Projekt LEENA arbeiten die Partnerfächer Ernährungsbildung und Englisch in einer Interventionsstudie zusammen, um sowohl die Gesundheitskompetenz von Jugendlichen als auch ihre kommunikative Handlungskompetenz in Englisch zu fördern. Im Anschluss an die Intervention wurden die Lernenden nach ihren Einschätzungen befragt. Der vorliegende Beitrag analysiert und interpretiert die Antworten und zeigt auf, welche Folgerungen sich daraus für ein fächervernetzendes Arbeiten ergeben können. (DIPF/Orig.)In the project LEENA, the two partner subjects Nutritional Science and English work together in an intervention study in order to foster both the health competency of adolescents and their communicative action competency in English. Following the intervention, the students were asked to assess the project. The current contribution analyses and interprets their answers and points out implications for interdisciplinary learning. (DIPF/Orig.

Stallmasse für die Haltung von Nutztieren im biologischen Landbau in der Schweiz (kurz: Stallmasse)

Das Merkblatt Stallmasse beinhaltet alle Stall- und Auslaufmasse für die Nutztierhaltung im Biolandbau. Die Zusammenstellung dient als Planungsinstrument für Tierhalter, als Hilfsmittel für die Beratung und als Nachschlagewerk für die Biokontrolle

The 2018 GaN power electronics roadmap

Gallium nitride (GaN) is a compound semiconductor that has tremendous potential to facilitate economic growth in a semiconductor industry that is silicon-based and currently faced with diminishing returns of performance versus cost of investment. At a material level, its high electric field strength and electron mobility have already shown tremendous potential for high frequency communications and photonic applications. Advances in growth on commercially viable large area substrates are now at the point where power conversion applications of GaN are at the cusp of commercialisation. The future for building on the work described here in ways driven by specific challenges emerging from entirely new markets and applications is very exciting. This collection of GaN technology developments is therefore not itself a road map but a valuable collection of global state-of-the-art GaN research that will inform the next phase of the technology as market driven requirements evolve. First generation production devices are igniting large new markets and applications that can only be achieved using the advantages of higher speed, low specific resistivity and low saturation switching transistors. Major investments are being made by industrial companies in a wide variety of markets exploring the use of the technology in new circuit topologies, packaging solutions and system architectures that are required to achieve and optimise the system advantages offered by GaN transistors. It is this momentum that will drive priorities for the next stages of device research gathered here

Senkung stickstoffbasierter Emissionen in Wirbelschichtanlagen durch den Einsatz von Onlinebilanzierungsmethoden

Zugleich: Dissertation, Universität Kassel, 202

Research into Insulating Low-Loss Compact Driver Circuits with an Integrated Control Unit for Regulating the Load Current

In dieser Arbeit werden Untersuchungen zu isolierenden, verlustarmen und zugleich kompakten Ansteuerschaltungen mit integrierter Regelung des Laststromes vorgestellt. Im Fokus steht insbesondere die Anwendung von Ansteuerschaltungen in mehrphasigen DC/DC-Wandlern mit hoher Leistungsdichte. Zur Reduzierung der Ansteuerverluste werden zwei neue Möglichkeiten vorgeschlagen. Das erste vorgestellte Verfahren zum Betrieb einer resonanten verlustarmen Ansteuerschaltung unterscheidet sich von den aus der Literatur bekannten Verfahren dadurch, dass zunächst die zur Umladung der Gatekapazität erforderliche Energie vollständig in einer Spule gespeichert wird. Unter Zugrundelegung einiger vereinfachender Annahmen wird es erleichtert, die bei der Umladung einer äquivalenten Gatekapazität entstehenden Ansteuerverluste zu berechnen. Durch die Herleitung einer geeigneten physikalischen Definition wird es möglich, den Wirkungsgrad der resonanten Ansteuerschaltung zu bestimmen. Danach entspricht der Wirkungsgrad einer verlustarmen Ansteuerschaltung dem Verhältnis von prozessierter Leistung zur Summe der prozessierten Leistung plus der hierbei entstehenden Verluste, wobei sich im Ergebnis für eine konventionelle spannungsgesteuerte Ansteuerschaltung ein Wirkungsgrad von 50 % ergibt. Das andere neuartige Verfahren zeichnet sich durch eine stufenweise Gateansteuerung aus. Hierfür zeigen die Berechnungen, dass der Wirkungsgrad dem Verhältnis von Stufenanzahl zu Stufenanzahl plus eins entspricht. Eine dreistufige Ansteuerung hat demnach einen Wirkungsgrad von bereits 75 %. Die Untersuchungen zu isolierenden Koppelelementen beginnen mit einer Betrachtung zum Stand der Technik. Um die hervorragenden Isolationseigenschaften von Standardleiterplattenmaterialien zu nutzen, wird hier ein neuer Ansatz zur galvanisch isolierten Übertragung der Ansteuersignale sowie der zur Umladung benötigten Ansteuerenergie vorgestellt. Dieser basiert auf der Verwendung von leiterplattenintegrierten Kondensatoren und Übertragern. Im direkten Vergleich von induktiven und kapazitiven leiterplattenintegrierten Koppelelementen erwies sich als vorteilhaft, aufgrund seines sehr viel geringeren Flächenbedarfs das induktive Koppelelement zur Übertragung der notwendigen Ansteuerleistung zu nutzen. Das kapazitive Koppelelement hingegen weist Vorteile bei der Übertragung der Ansteuersignale auf. Zum einen erfordert es prinzipbedingt eine deutlich geringere Stromaufnahme. Zum anderen zeigt es deutlich geringere Wechselwirkungen mit den unvermeidbaren parasitären Zuleitungsinduktivitäten, was besonders bei der Übertragung sehr hochfrequenter Signale von Bedeutung ist. Zur störsicheren Übertragung wird die in der Nachrichtentechnik bekannte Manchester Leitungskodierung vorgeschlagen. Zur Umgehung der Trägerrückgewinnung wird in der Arbeit stattdessen ein Verfahren mit separater Übertragung des Trägersignals empfohlen. Bei Betrachtung der verschiedenen dem Stand der Technik entsprechenden Lösungen zur Regelung des Laststroms sowie der dabei verwendeten Verfahren zur Strommessung, kommt die Frage auf, welche Bandbreite für eine galvanisch isolierte Stromerfassung benötigt wird. Anhand des direkten Vergleichs einer Mittelwert-Stromregelung mit einer Spitzenwert-Stromregelung zeigt sich, dass die Spitzenwert-Stromregelung keine den Stromverlauf exakt abbildende Phasenstromerfassung benötigt. Unter der Annahme, dass der Stromsensor ein Tiefpassverhalten erster Ordnung aufweist, ist für diesen in der Anwendung einer Spitzenwert-Stromregelung eine 3-dB-Bandbreite in der Höhe eines Viertels der Schaltfrequenz des zu regelnden DC/DC-Wandlers ausreichend. Hiermit kann ein günstigeres dynamisches Strom-Führungsverhalten erzielt werden, als mit einem Stromsensor vierfacher Bandbreite in der Anwendung einer Mittelwert-Stromregelung. Hierzu bedarf es allerdings einer Korrektur des Stromsollvorgabewertes. Aufgrund der geringen notwendigen Bandbreite wird in dieser Arbeit die Bezeichnung „Low Bandwidth Current Mode Control“ für das modifizierte Stromregelungsverfahren eingeführt. In Kombination mit einer Stromerfassung, welche auf der Auswertung des parasitären Spulenwiderstands beruht, führt das modifizierte Stromregelungsverfahren zu sehr kompakten Lösungen für das Stromsymmetrierungsproblem bei mehrphasigen Hoch-Tiefsetzstellern. Basierend auf den Ergebnissen der vorangegangenen theoretischen Untersuchungen wurde im Rahmen der Arbeit eine isolierende, verlustarme, kompakte Ansteuerschaltung für eine Halbbrückentopologie mit integrierter Regelung des Laststroms entwickelt und realisiert.In this thesis studies on insulating low-loss compact driver circuits with an integrated control unit for regulating the load current are presented. The main focus is laid on driver circuits for high power density multiphase DC/DC converters. Two new possibilities of designing driver circuits which reduce gate drive losses are examined. The first solution, a low-loss resonant driver circuit, differs from that one known in literature by the fact that the energy required to reload the gate capacity is stored entirely in a coil first. By using some simplifications it is possible to calculate the losses when charging an equivalent gate capacity. By deriving a suitable physical definition it is possible to determine the efficiency of the resonant driver circuit. Using this definition, the efficiency of a low-loss driver circuit corresponds to the ratio of the power processed to the sum of the power processed and the losses occurring through out the process. This results in an efficiency of 50 % for a conventional voltage controlled driver circuit. For the other new solution with a stepwise gate control the calculations show that the efficiency corresponds to the relation of step numbers to the sum of step numbers plus one. Consequently, a three-stage control has an efficiency of already 75 %. The research on insulating coupling elements begins with the consideration of the state of the art technology. To use the outstanding isolation qualities of standard printed circuit board materials a new approach is presented for the galvanically insulated transmission of the gate control signals as well as for the energy required to reload the gate capacity, which is based on the use of printed circuit board integrated capacitors and transformers. A comparison of inductive and capacitive printed circuit board integrated coupling elements showed that it is of advantage to use the inductive coupling element for the transmission of the necessary gate drive energy because of its reduced amount of circuit board area. However, the capacitive coupling element has advantages when transmitting the gate control signals. On the one hand it has a much lower current consumption. On the other hand it shows much less interaction with the unavoidable parasitic leakage inductances, which is particularly important during the transmission of very high frequency signals. It is suggested to use the Manchester coding, which is well-known in communications engineering, for a fail-safe transmission of the gate drive signals. To avoid the need to reconstruct the carrier signal, it is suggested to transmit the carrier signal separately. Considering state of the art solutions to control the current of buck-boost converters the question raises how to find the necessary current measurement bandwidth particularly if a galvanically isolated current measurement unit is used. Comparing the average current mode control with the peak current mode control shows that the peak current mode control does not need an exact current measurement signal. Under the assumption that the current measurement unit shows the behavior of a first-order low-pass filter, a 3-dB-bandwidth in the range of one fourth of the switching frequency is sufficient for it when used for peak current mode control. With this kind of current measurement unit the behavior of the modified current control is better than that of an average current mode control even if it uses a measurement unit which is four times faster. However, this requires a correction of the desired current value. Due to the low 3-dB-bandwidth which is necessary, it is suggested to use the term “low bandwidth current mode control” for the modified current mode control scheme. If combined with a current measurement which is based on the evaluation of the parasitic coil resistance, the modified current mode control scheme leads to very compact solutions for balancing the currents in multiphase buck-boost converters. Based on the results of the theoretical analysis, an insulating, low-loss, compact gate drive circuit for a half bridge with integrated control of the load current was developed and realized

Assessing the resilience of stochastic dynamic systems under partial observability.

Resilience is a property of major interest for the design and analysis of generic complex systems. A system is resilient if it can adjust in response to disruptive shocks, and still provide the services it was designed for, without interruptions. In this work, we adapt a formal definition of resilience for constraint-based systems to a probabilistic framework derived from hidden Markov models. This allows us to more realistically model the stochastic evolution and partial observability of many complex real-world environments. Within this framework, we propose an efficient and exact algorithm for the inference queries required to construct generic property checking. We show that the time complexity of this algorithm is on par with other state-of-the-art inference queries for similar frameworks (that is, linear with respect to the time horizon). We also provide considerations on the specific complexity of the probabilistic checking of resilience and its connected properties, with particular focus on resistance. To demonstrate the flexibility of our approach and to evaluate its performance, we examine it in four qualitative and quantitative example scenarios: (1) disaster management and damage assessment; (2) macroeconomics; (3) self-aware, reconfigurable computing for aerospace applications; and (4) connectivity maintenance in robotic swarms

Heterogeneous integration of vertical GaN power transistor on Si capacitor for DC-DC converters: Presentation held at ESTC 2018, IEEE 7th Electronics System-Integration Technology Conference, September 18th-21st, 2018, Dresden, Germany

Point of load (PoL) converters are emerging as common solution for industrial applications, telecommunications, server, and aerospace. In this work, a topology is designed for a single stage 48 V to 1 V PoL converter by using new gallium nitride (GaN) devices and integrated silicon capacitors. Various wafer-level packaging concepts such as die-to-wafer bonding, wafer-level thinning, and through-silicon via (TSV) will be presented and discussed based on this topology. Furthermore, two novel devices will be developed and used for the packaging concepts. One is a GaN transistor with vertical channel, which will exhibit significantly lower power losses when switching and converting power. The other is an integrated silicon capacitor with lateral geometry, in which positive and negative electro des are insulated from the substrate and formed on the same side. Simulation is performed to compare the parasitic inductance from the different concepts. A direct bonding process is shown to provide flexibility in engineering new device geometries and can be exploited to mitigate the electrical parasitics

Development and psychometric evaluation of the MetabQoL 1.0: a quality of life questionnaire for paediatric patients with intoxication-type inborn errors of metabolism

INTRODUCTION This study is part of the "European network and registry for intoxication type metabolic diseases" (E-IMD) project. Intoxication-type inborn errors of metabolism (IT-IEM) such as urea cycle disorders (UCD) and organic acidurias (OA) have a major impact on patients' lives. Patients have to adhere to strict diet and medication and may suffer from metabolic crises and neurocognitive impairment. Disease-specific health-related quality of life (HrQoL) assessment questionnaires are the method of choice to estimate the subjective burden of a disease. To date, no such instrument is available for IT-IEM. METHODS Disease-specific patient- and parent-reported HrQoL questions were constructed in German based on focus group interviews with patients and parents. Questionnaires for patients from 8 to 18 years were piloted with 14 participants (n = 9 children and adolescents, n = 5 parents) by cognitive debriefing and tested psychometrically with 80 participants (n = 38 patients, n = 42 parents) for item characteristics, validity, and reliability to construct the first version of a disease-specific HrQoL questionnaire. RESULTS Twenty-eight questions were selected based on item descriptives. Scales of self- and proxy questionnaires demonstrated acceptable to excellent reliability in terms of internal consistency (Cronbach's α = 0.70-0.93). Scales and total scores correlated with those of generic HrQoL questionnaires, showing convergent validity. DISCUSSION The MetabQoL 1.0 questionnaire exhibits sound psychometric properties and is a promising step towards assessing patient-reported outcomes in research and clinical practice. It provides a solid basis for translation into other languages and further elaboration and psychometric exploration in larger populations

PKHD1, the Polycystic Kidney and Hepatic Disease 1 Gene, Encodes a Novel Large Protein Containing Multiple Immunoglobulin-Like Plexin-Transcription–Factor Domains and Parallel Beta-Helix 1 Repeats

Autosomal recessive polycystic kidney disease (ARPKD) is a severe form of polycystic kidney disease that presents primarily in infancy and childhood and that is characterized by enlarged kidneys and congenital hepatic fibrosis. We have identified PKHD1, the gene mutated in ARPKD. PKHD1 extends over ⩾469 kb, is primarily expressed in human fetal and adult kidney, and includes a minimum of 86 exons that are variably assembled into a number of alternatively spliced transcripts. The longest continuous open reading frame encodes a 4,074-amino-acid protein, polyductin, that is predicted to have a single transmembrane (TM)-spanning domain near its carboxyl terminus, immunoglobulin-like plexin-transcription–factor domains, and parallel beta-helix 1 repeats in its amino terminus. Several transcripts encode truncated products that lack the TM and that may be secreted if translated. The PKHD1-gene products are members of a novel class of proteins that share structural features with hepatocyte growth-factor receptor and plexins and that belong to a superfamily of proteins involved in regulation of cell proliferation and of cellular adhesion and repulsion