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INFLUENCE OF A NOVEL SOLID THERMAL ISOLATION MATERIAL FOR MEMS ON THERMOPILE SENSITIVITY AND DYNAMIC RESPONSE OF A MEMS FLOW SENSOR
No full text787790This paper reports on the wafer-level modification of thin film flow sensors with a novel solid porous material for mechanical stabilization against overpressure events. A solid porous support is formed beneath the sensor membranes by agglomeration of dry powder using atomic layer deposition (ALD). Pressure testing of modified membranes shows resistance to overpressure events with a magnitude of at least 0.8 MPa (8 bar). For the first time, the effect of this approach on the static and dynamic response of the sensor's thermopiles is reported. The addition of porous microstructures is found to only have a moderate effect on sensor performance by slightly decreasing the thermopile sensitivity from 7.5 mV/mW to 5.5 mV/mW and increasing the time constant from 3.6 ms to 7.2 ms. These results demonstrate that the proposed technology is highly promising for the development of non-fragile thermal isolation structures for MEMS
Frühjahrstagung 2022 des AK FTI: Neue Ansprüche an das Monitoring von FTI-Programmen
No full text19420022
Local fatigue assessment of butt-welded joints between additively manufactured 316L stainless steel parts
No full text1421Additive manufacturing (AM) has seen a rapid increase in application for many applications in recent years; nevertheless, there are still technical limitation with respect to widespread industrial applications. One important aspect is the relative limited building volume of the laser powder bed fusion (LPBF) process. Thus, the joining of AM parts makes it possible to increase the volume of AM structures; however, it is currently unclear whether welded AM parts can be assessed using fatigue assessment concepts typically applied for welded components. In particular, local fatigue assessment concepts seem to be suitable for this task, as they are capable to assess complex part and weld geometries. In this study, local concepts based on the micro-structural support effect hypothesis are applied as they also account for support effects at weld transitions. The considered methods are the critical distance and the IBESS approach. To investigate their applicability, fatigue tests were performed on butt-welded joints of 316L AM steel plates made by gas metal arc welding. To account, for the different weld seam position relative to the LBPF building process, joints were produced with weld seams parallel and vertical to the layer orientation of AM plates. For all three test series, the local fatigue assessment concepts lead to conservative results; however, the comparison between numerical and test results also reveal some shortcomings of the chosen concepts
Benchmark Concept for Industrial Pick&Place Applications
No full textRobotic grasping and manipulation is a highly active research field. Typical solutions are usually composed of several modules, e.g. object detection, grasp selection and motion planning. However, from an industrial point of view, it is not clear which solutions can be readily used and how individual components affect each other. Benchmarks used in research are often designed with simplified settings in a very specific scenario, disregarding the peculiarities of the industrial environment. Performance in real-world applications is therefore likely to differ from benchmark results. In this paper, we present a concept for the design of general Pick&Place benchmarks, which help practitioners to evaluate the system and its components for an industrial scenario. The user specifies the workspace (obstacles, movable objects), the robot (kinematics, etc.) and chooses from a set of methods to realize a desired task. Our proposed framework executes the workflow in a physics simulation to determine a range of system-level performance measures. Furthermore, it provides introspective insights for the performance of individual components
Empowering the Emerging
No full text160165Urban innovation ecosystems foster technological progress, economic growth, and global competitiveness, involving networks of businesses, academic institutions, public authorities, and community organizations. Effective governance in these ecosystems is key to coordinating activities, enabling knowledge exchange, and ensuring longterm sustainability. While much research has focused on ecosystem types and characteristics, the relationship between governance structures and their practical implementation remains underexplored. This study addresses this gap by analyzing governance mechanisms through a mixed-method approach, including literature review and expert interviews. The findings offer actionable insights to improve governance practices and to promote resilient and adaptable ecosystems
Vvenc: An Open and Optimized Vvc Encoder Implementation
No full textThe recently finalized Versatile Video Coding (VVC) standard promises to reduce the video bitrate by 50% compared to its predecessor, High Efficiency Video Coding (HEVC). The increased efficiency comes at a cost of increased computational burden. The Fraunhofer Versatile Video Encoder VVenC is the first openly available optimized implementation providing access to VVC's efficiency at only 46% of the runtime of the VVC test model VTM, when not using multi-Threading. An alternative operating point allows 30 \times faster encoding for the price of around 12% bitrate increase, while still providing around 38% bitrate reduction compared to HEVC test model HM. In the fastest configuration, VVenC runs over 140 \times faster than VTM while still providing over 10% bitrate reduction compared to HM. Even faster encoding is possible with multi-Threading. This paper provides an overview of VVenC's main features and some evaluation results
Stereo Reproduction in the Presence of Sample Rate Offsets
No full textOne of the main challenges in synchronizing wirelessly connected loudspeakers for spatial audio reproduction is clock skew. Clock skew arises from sample rate offsets (SROs) between the loudspeakers, caused by the use of independent device clocks. While network-based protocols like Precision Time Protocol (PTP) and Network Time Protocol (NTP) are explored, the impact of SROs on spatial audio reproduction and its perceptual consequences remains underexplored. We propose an audio-domain SRO compensation method using spatial filtering to isolate loudspeaker contributions. These filtered signals, along with the original playback signal, are used to estimate the SROs, and their influence is compensated for before spatial audio reproduction. We evaluate the effect of the compensation method in a subjective listening test. The results of these tests, as well as objective metrics, demonstrate that the proposed method mitigates the perceptual degradation introduced by SROs by preserving the binaural cues
Removing power lines from digital surface models using OSM data
No full textA digital surface model (DSM) is crucial for various applications, such as visibility analysis, and are often commonly available. Depending on the sampling method of a DSM from 3D point clouds, power lines may be projected into the two-dimensional domain. The resulting artifacts represent a strong obstacle to automatic computation of visibility. To clean free DSM data from these artifacts, we propose an effective method that relies on the available OpenStreetMap (OSM) data and is widely unsupervised. After fetching relevant OSM data and creating buffers around power line features, we apply image processing techniques, including edge detection and Hough transform to accomplish the removal of artifacts left behind by power lines in DSMs. Hereby, care is taken to preserve vegetation under power lines. The proposed method is robust, easily adaptable, and fast, making its application suitable for large-scale data and contributing to the democratization of the access to high-quality geodata processing
Phase-locked and phase-tuned resonant-MOEMS external cavity QCLs and their application for fast and broadband mid-infrared reflectometry
No full textThe combination of broadband quantum cascade lasers (QCLs) with micro-electro-mechanical system (MOEMS) scanners having an integrated diffraction grating as emission-wavelength-selective element enables the realization of very compact, rapidly tuneable, and robust light sources for mid-infrared spectroscopy. In contrast to a motor-driven mechanical grating tuning mechanism, MOEMS scanners do not limit the lifetime of the laser module, as they are made from single-crystalline silicon and undergo no mechanical wear1</sup