600 Technik, Technologie
Refine
Year of publication
Document Type
- Conference Proceeding (104)
- Contribution to a Periodical (34)
- Report (16)
- Article (peer reviewed) (14)
- Part of a Book (1)
- conferencepaper (1)
- Doctoral Thesis (1)
- Other (1)
Is part of the Bibliography
- no (172)
Keywords
- Schallmesstechnik (85)
- Holzbau (54)
- Photovoltaik (9)
- DC/DC converter (8)
- Leichtbau (5)
- Raumakustik (5)
- Reinraum (4)
- Altbausanierung (3)
- Brettsperrholz (3)
- EMC (3)
Institute
- Fakultät für Angewandte Natur- und Geisteswissenschaften (102)
- Fakultät für Ingenieurwissenschaften (47)
- Fakultät für Wirtschaftsingenieurwesen (6)
- Zentrum für Forschung, Entwicklung und Transfer (6)
- Fakultät für Innenarchitektur, Architektur und Design (5)
- Fakultät für Holztechnik und Bau (4)
- Forschung und Entwicklung (2)
- Fakultät für Angewandte Gesundheits- und Sozialwissenschaften (1)
In today’s tense geopolitical landscape, marked by strained relations among major powers and deep-rooted dependence on fossil-based economies, the emerging modern bioeconomy can provide resource independence and resilience, in tandem with economic, social, and environmental benefits, and thus has the potential to underpin a sustainable future. The bioeconomy is a vital cross-cutting meta-sector, but it is not inherently circular or sustainable; without intentional design, it risks becoming a linear, unsustainable replacement of the fossil-based economy. Realising its full promise requires purposeful engineering to address climate change, biodiversity loss, strengthen resource independence, support food security and resilience, create jobs, promote social inclusion, boost competitiveness and autonomy, and improve human, animal, and environmental health. The potential is enormous, but so are the challenges society faces in realising the vision for a biobased, nature-positive future.
Circular economy (CE) has become important in reducing the environmental impact of the construction sector. For the transformation from linear to CE, decision support tools and methods are needed to assess and promote CE for constructions. With regard to sustainable financial decisions, life cycle costing (LCC) is the preferred method. However, the LCC approaches and their application in CE research differ. Based on a systematic literature review,
the relevance of refurbishment in operation, reuse, recycling and disposal at end-of-life (EoL) in LCC is assessed. As a result, LCC has gained relevance in the construction sector, but CE plays a subordinate role in LCC applications. Costs or benefits of CE are often neglected. However, some research have shown that refurbishment as well as reuse and recycling can outweigh higher initial cost over lifetime. The internalisation of environmental and social impacts or even benefits are also rare. In particular, there is a lack of research on how to internalise the environmental benefits of refurbishment, reuse and recycling or how to effectively incentivise higher CE efforts in LCC in order to encourage decision-making in construction towards CE.
Der Arbeitsbereich 2 des Verbundvorhabens hatte als Ziel, die Anwendbarkeit von Dämmstoffen aus nachwachsenden Rohstoffen unter dem Aspekt des Schallschutzes deutlich zu erhöhen.
Ein zentrales technisches Ergebnis des Projektes stellt der erweiterte Bauteilkatalog für Holzbauteile dar, der eine umfangreiche Sammlung an Planungsdaten bietet. Dieser wurde auf Basis der Analyse und Aufbereitung vorhandener Messdaten sowie der im Projekt durchgeführten Prüfungen erstellt. Innerhalb des Projektes wurden
• 45 Deckenaufbauten und
• 10 Wandkonstruktionen hinsichtlich ihrer schalltechnischen Eigenschaften untersucht. Dabei wurden Holztafelkonstruktionen und Massivholzkonstruktionen berücksichtigt. Die ermittelten Werte zeigen, dass mit den Deckenaufbauten beim Einsatz von Holzfaser-Trittschalldämmplatten sehr gute Ergebnisse erreichbar sind. Bei entsprechender Gesamtkonstruktion können somit auch mit steiferen NawaRo-Dämmplatten die Zielwerte für Trenndecken eingehalten werden. Neben der Entwicklung dieser speziell für NawaRo-Dämmstoffe optimierten Aufbauten, konnte für den gesamten Bauteilkatalog eine Öffnung für Hohlraumdämmstoffe aus nachwachsenden Rohstoffen erreicht werden. NawaRo-Dämmstoffe zur Hohlraumdämpfung sollten dabei einen längenbezogenen Strömungswiderstand zwischen 5 kPa s/m² und 50 kPa s/m² und eine offene Porosität größer als 0,9 (entspricht bei den meisten untersuchten Dämmstoffen etwa einer Rohdichte ≤ 130 kg/m³) aufweisen. Zusätzliche Messungen mit höherer flächenbezogener Masse der Unterdecke zeigten den positiven Einfluss von brandschutz-technisch erforderlichen Zusatzbeplankungen gerade bei den besonders interessierenden tiefen Frequenzen. Ein wissenschaftliches Ergebnis des Projektes ist in der Weiterentwicklung der Simulationsmodelle für die Schallübertragung zu sehen. Hierzu konnten die semianalytischen Modelle für die Berücksichtigung der Materialeigenschaften unterschiedlicher Hohlraumdämmstoffe erweitert werden. Als zweites Simulationsmodell wurde die Finite-Elemente-Methode für die Berechnung der Schalldämmung eingesetzt. Für die Simulation wurde ein Massivholz-Wandelement mit Wärmedämm-Verbund-System als Außenwand modelliert. Diese Außenwandkonstruktion ist von besonderem Interesse, da sie im mehrgeschossigen Wohnungsbau gerne verwendet wird, aber sowohl im Brandschutz als auch im Schallschutz noch Optimierungsbedarf aufweist.
This paper details the development of an accelerated AC cycling test bench for evaluating the aging mechanisms of SiC MOSFET power modules. Contrary to classical HTGS and DGS which only exercise gate source stresses the AC Cycler switched under high voltage and current. Operating for about 235 hours, the system maintained stable thermal conditions thanks to an integrated cooling system. Key precursors of aging, such as increases in threshold voltage and on-state resistance were identified using static characterization curve tracer before and after the test. Gate charge and Vdson were also measured on-line with specially developed gate drivers.
We propose to introduce environmental sustainability in a radio frequency (RF) and electromagnetic compatibility (EMC) laboratory course for an electrical engineering bachelor’s program utilizing reusable, easily recyclable and ecologically harmless (biodegradable) circuits. Our concept is based on the replacement of state-of-the-art printed circuit boards by substrates with mechanically structured adhesive Cu and Zinc films. Furthermore, organic based circuit carriers can be substituted by biodegradable paper substrates. As an example for the RF lab, we discuss the design, simulation and experimental characterization of a microwave low-pass
filter with 1.2GHz cut-off frequency. Secondly, for an EMC lab we suggest a prototype for power integrity (PI) studies based on the current imbalance method for reducing common mode radiated emission. As a novel feature during the lab course, the instructor in addition gives a
lecture highlighting the electronic waste challenge, which is accompanied by group discussions on sustainability and recycling. As a final lab course task students are asked to disassemble the boards or prepare them for reuse, followed by material sorting and submission to recycling
institutions.
We present an air coil with bistable compliant single layer windings. Due to stable elastic snapping deformation of wire segments, the self-inductance of the air coil can be precisely varied in multiple steps. A numerical and analytical design methodology is proposed and successfully validated by magneto-quasi-static field simulations and experiments on prototypes.
We propose near-field inductive power transfer with three coils in the frequency range of a few MHz. The relay coil is part of a non-linear resonator having a diode connected in parallel to the resonant capacitor. We achieve power transfer at multiple frequencies which can be tuned by the input power level and mutual coupling between the coils. Higher harmonic generation is found dominant at lower input power, whereas subharmonic generation (period doubling and period quadrupling) is observed at high levels. Power transfer at subharmonics reveals robustness against level perturbations due to pronounced amplitude hysteresis effect. A circuit simulation based on standard non-linear diode SPICE models confirms the experimental results which are obtained on a demonstration prototype.
The measurement of IV curves is the most important characterization technique of photovoltaic devices. This work seeks to determine a fair sampling rate for IV curves. Traditional sampling methods, such as using equidistant voltage steps, result in biased data by over- and undersampling the measurement at different voltages, which affect critical evaluations such as maximum power point (MPP) determination as well as series and shunt resistance estimation. Therefore, an adaptive sampling approach based on calculating the arc length of the IV curve is proposed, aiming to distribute data points equidistantly along the curve. This method is intended to provide a more balanced representation of the measurement data across all segments of the curve. The results indicate that using this adaptive approach, the measurement points can be significantly reduced at lower voltages while maintaining essential data density at key characteristics such as the MPP, facilitating faster and more accurate assessments.
Purpose Climate change mitigation is one of the priorities of the European Bioeconomy Strategy (BES). In this regard, renewable raw materials are a crucial resource, as they help to substitute fossil resources and reduce greenhouse gas (GHG) emissions by storing biogenic carbon (C). To control the environmental impact of the European BES, the life cycle assessment (LCA) is the preferred method. Standards provide guidance for LCA. This review aims to present the state of the art of LCA-related standards, focusing on the assessment of biogenic C and its global warming potential (GWP) to evaluate them for decision-making with regard to the transition to a bioeconomy (BE) and climate change mitigation.
Methods A systematic review is conducted using the database Nautos to reveal the relevant standards guiding LCA in the BE. In an iterative process, criteria for a comparative analysis are defined. The eligible standards are then qualitatively analysed and compared based on criteria previously derived in the iterative process.
Results and discussion In the context of LCA and bio-based products, 13 documents are identified. Differences are revealed in the accounting of biogenic C flows, the calculation of the duration of biogenic C storage and the biogenic C content as well as the consideration of substitution effects. Furthermore, the standards do not provide any information on the assessment of biogenic C in the circular economy so far.
Conclusion The importance of biogenic C aspects in LCA has been reflected in the standards over the last 20 years. However, further research is needed to harmonise the different aspects and integrate new relevant ones related to biogenic C and BE to support decision-making for the transition to a BE. This becomes more important as new legislation refers to LCA standards as the preferred assessment method.