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Influence of different cooling strategies during hard turning of AISI 52100 - Part II: Characterization of the surface and near surface microstructure morphology 5

Influence of different cooling strategies during hard turnin...

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5th CIRP Conference on Surface Integrity, CSI 2020

作者： Ankener, Werner Uebel, Julian Basten, Stephan Smaga, Marek Kirsch, Benjamin Seewig, Jörg Aurich, Jan C. Beck, Tilmann Institute of Materials Science and Engineering TU Kaiserslautern Gottlieb-Daimler-Str. Kaiserslautern67663 Germany Institute for Measurement and Sensor Technology TU Kaiserslautern Gottlieb-Daimler-Str. Kaiserslautern67663 Germany Institute for Manufacturing Technology and Production Systems TU Kaiserslautern Gottlieb-Daimler-Str. Kaiserslautern67663 Germany

This two-part paper addresses the impact of seven different cooling conditions on the finishing process as well as the resulting surface and near-surface microstructure morphology of the rolling bearing steel AISI 52100 in martensitic heat treatment state. The applied cooling strategies are liquid nitrogen (LN2-) cooling, CO2-snow cooling at varied mass flows, sub-zero metalworking fluids (MWF) at varied supply temperatures, and dry machining. Part II of the paper concerns the changes in surface roughness, examined by an angle resolved scatter light sensor, micro hardness measurement, microstructure observations, residual stress and phase composition analyses in the near-surface area, caused by the turning process, that is characterized in Part I. The lowest cooling performance, i.e. dry machining, results in low compressive axial residual stresses and a high proportion of retained austenite at the near-surface area. High cooling performance strategies like CO2 cooling or sub-zero MWF show an opposite distribution of the mentioned parameters, wherein the coolants' lubrication effect is an important aspect. Microstructural differences resulting from the process parameters used in these investigations tend to be less significant. Thus, they do not allow reliable assignment of the microstructure to the cooling strategies used. However, different cooling conditions show an impact on residual stresses, phase distribution and surface topography of the workpieces to varying extents. © 2020 The Author(s).

关键词： Cooling

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Forward Modelling of the Human Thorax for Electrical Impedance Tomography measurements

Forward Modelling of the Human Thorax for Electrical Impedan...

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Impedance Spectroscopy (IWIS), International Workshop on

作者： Hamdi Haddad Oumaima Bader Mariem Hafsa Najoua Essoukri Ben Amara Olfa Kanoun University of Sousse National Engineering School of Sousse Sousse Tunisia LATIS- Laboratory of Advanced Technology and Intelligent Systems Université de Sousse Ecole Nationale d'Ingénieurs de Sousse Sousse Tunisie Professorship of Measurement and Sensor Technology Technische Universität Chemnitz Chemnitz Germany

Electrical Impedance Tomography (EIT) is a medical imaging technique that reflects the inner conductivity distribution of biological tissue based on boundary voltages measured at the electrodes around the thorax while injecting an alternating current with a low amplitude. In this work, a 16-electrode thorax mesh is implemented for the pyEIT library. This mesh builds the basis for the reconstruction of the conductivity distributions from real human thorax voltage measurements. Post-processing techniques, such as the K-means method and the region based segmentation, have also been implemented. The resulting re-constructed images reflect the conductivity changes during the breathing cycle and by post-processing artifacts are eliminated leading to a clear image of the lungs and the heart.

关键词： Heart Electrical impedance tomography Image segmentation Voltage measurement Impedance measurement Lung Conductivity

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A parallel Architecture of a Genetic Algorithm for EIT Image Reconstruction

A parallel Architecture of a Genetic Algorithm for EIT Image...

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IEEE SSD International Multi-Conference on systems, Signals and Devices

作者： Mariem Hafsa Bilel Ben Atitallah Taha Ben Salah Najoua Essoukri Ben Amara Olfa Kanoun Professorship of Measurement and Sensor Technology Technische Universität Chemnitz Chemnitz Germany National Engineering School of Sousse University of Sousse Sousse Tunisia Université de Sousse Ecole Nationale d'Ingénieurs de Sousse LATIS-Laboratory of Advanced Technology and Intelligent Systems Sousse Tunisie

ISBN: (纸本)9781665414937;9781665430579

Nowadays, electrical impedance tomography (EIT) has become an interesting bio-medical imaging technique, it is non-invasive and shows great potential in medical investigation. The EIT presents high performances in conductivity mapping of the inner structure of a specific target. A set of electrodes are placed around the measured target where an excitation current is injected in a pre-defined frequency. This excitation will cause a variation of the potential distribution and consequently in the conductivity distribution of the measured medium. Therefore, boundary voltages are recorded, which will be used to provide the tomography image of the addressed cross-section. In this paper, the focus will be on the image reconstruction algorithm in order to reach high-quality images. A water tank set-up is used for the experiments where a conductive object is placed inside. Then, a genetic algorithm has been implemented in a parallel form to reduce the execution time by using a master/slave architecture. Moreover, to reach a high and accurate conductivity image, a reference technique has been integrated called the non-blind search. Further, a comparison study of genetic operators' configuration is carried out in terms of fitness values and object position identification. Nine combinations are tested, where the uniform crossover/random mutation shows the highest performance in object position identification with a fitness value equal to 0.0505. A comparison between the implemented solution and commonly used algorithms is established as well, where the genetic algorithm was able to outperform them in terms of fitness values.

关键词： Electric potential Current measurement Conductivity Genetics Storage tanks Frequency measurement Object recognition

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Epileptic Seizure Motion Classification based on sEMG and Artificial Neural Network

Epileptic Seizure Motion Classification based on sEMG and Ar...

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Impedance Spectroscopy (IWIS), International Workshop on

作者： Achraf Djemal Dhouha Bouchaala Ahmed Fakhfakh Olfa Kanoun Laboratory of Signals Systems Artificial Intelligence and Networks National School of Electronics and Telecommunications of Sfax University of Sfax Tunisia Digital Research Centre of Sfax Tunisia National Engineering School of Sfax University of Sfax Tunisia Chair of Measurement and Sensor Technology Chemnitz University of Technology Chemnitz University Germany

According to the World Health Organization (WHO), 70% of all epileptic seizures are convulsive, making the EMG signal one of the essential signals used for epilepsy treatment. Nevertheless, epileptic seizure classification remains a challenge. Suitable machine learning classifiers and features are the critical metrics for good performance. In this paper, a collection of widely used time-domain features of surface electromyography (sEMG) signals is illustrated and an investigation of their ability to distinguish epileptic seizures is reported for five subjects performing myoclonic and tonic seizures using eight sEMG sensors placed on different muscles: Biceps brachii, flexor carpi ulnaris, gastrocnemius, and quadriceps. Feature selection step is required to eliminate information redundancy and irrelevant before epileptic seizure classification. The results show that extracting Waveform Length, Integrated EMG, Variance, Shannon Entropy, Complexity, Skewness, and Root Mean Square values are more significant for myoclonic-tonic seizure classification based on sEMG signal analysis. Selected features have been subjected to the Artificial Neural Network classifier. An overall epileptic seizure accuracy of 96% could be achieved by the ANN algorithm based on seven selected features.

关键词： Surface impedance Spectroscopy Epilepsy Artificial neural networks Muscles Feature extraction Electromyography

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Micro milling of areal material measures –Study on surface generation for different up and down milling strategies

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Procedia CIRP 2020年 87卷 13-18页

作者： Katja Klauer Matthias Eifler Benjamin Kirsch Jörg Seewig Jan C. Aurich Institute for Manufacturing Technology and Production Systems TU Kaiserslautern Gottlieb-Daimler Str. 67663 Kaiserslautern Germany Institute for Measurement and Sensor-Technology TU Kaiserslautern Gottlieb-Daimler Str. 67663 Kaiserslautern Germany

Ball end micro milling is a suitable process for the manufacturing of freeform surfaces and therefore appropriate for the manufacturing of material measures according to ISO 25178-70. In previous studies of the authors, ball end micro milling of areal material measures with specified microstructures was experimentally investigated and the influence of the cutting parameters, as well as the influence of the control dataset parameters and the tilt angle were systematically analyzed. The influences of the surface generation strategy (up or down milling) and the chosen tool path on the surface quality of the manufactured structure are investigated experimentally in this study. For this purpose, a full factorial experimental design is created in which two different areal material measure geometries (ACS and AFL as described in ISO 25178-70) are examined applying two different tools in two different surface generation strategies (up or down milling). In addition, two different cases per surface generation strategy are tested: the tool is retracted in the milled groove (case 1: reverse movement with engaged tool) or the tool is lifted between two paths (case 2: reverse movement without tool contact). On the basis of these two cases it is possible to evaluate how the repeatability of the z-axis (case 1) or the smaller short-wavelength roughness due to the second cut (case 2) influences the surface quality of the milled structure. In addition, a meander-shaped tool path is tested as reference: the tool moves alternately in up and down milling direction without lifting from the workpiece. The meander-shaped tool path is the most time-efficient and was applied in previous studies. As a result, information on the influence of the milling strategy on dimensional accuracy and surface roughness is provided. The quality of the manufactured surfaces is compared both quantitatively (based on areal surface texture parameters) and qualitatively (measured topography compared to nominal

关键词： ball end micro milling material measures surface generation strategy

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Embedded Air-Coupled Ultrasonic 3D Sonar System with GPU Acceleration

Embedded Air-Coupled Ultrasonic 3D Sonar System with GPU Acc...

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IEEE sensorS

作者： Gianni Allevato Matthias Rutsch Jan Hinrichs Marius Pesavento Mario Kupnik Measurement and Sensor Technology Group Technische Universität Darmstadt Darmstadt Germany Communication Systems Group Technische Universität Darmstadt Darmstadt Germany

ISBN: (数字)9781728168012

ISBN: (纸本)9781728168029

Air-coupled ultrasonic sonar systems are a valuable complement to lidar sensors for safe navigation of autonomous vehicles, especially in environments with optically transparent and reflective surfaces. Consequently, sonar systems based on phased arrays and beamforming are a promising compact solution, providing precise and unambiguous 3D localization of multiple objects in a wide field of view. However, a cost-effective and viable integration is challenging due to the increased component count and computational effort. Therefore, we present an embedded phased array sonar system requiring a minimum number of low-cost components, and providing high frame rates. The system contains 36 digital MEMS microphones, one 40 kHz transducer, an FPGA for CIC-filtering and communication with the main processor (Nvidia Jetson Nano) via Hi-Speed USB or WiFi. The GPU accelerated frequency-domain signal processing consisting of matched filtering, optimized conventional narrow-band beamforming and envelope extraction, enables frame rates up to 30 Hz. In an anechoic chamber, a field of view of ±80° and an angular resolution of 14° have been measured using two Ø100 mm spheres. Therefore, this self-contained phased array sonar allows a practicable sensor fusion with lidar data for a more reliable monitoring of the environment.

关键词： Sonar Sonar measurements Head Array signal processing Acoustics Universal Serial Bus Transducers

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Design of a DC-DC Boost Converter of Hybrid Energy Harvester for Low-Power Biomedical Applications

Design of a DC-DC Boost Converter of Hybrid Energy Harvester...

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IEEE SSD International Multi-Conference on systems, Signals and Devices

作者： Meriam Ben Ammar Salwa Sahnoun Ahmed Fakhfakh Olfa Kanoun Digital Research Center of Sfax (CRNS) Laboratory of Technologies for smart systems (LT2S) Sfax Tunisia Chemnitz University of Technology Measurement and Sensor Technology Chemnitz Germany

ISBN: (数字)9781728110806

ISBN: (纸本)9781728110813

The growing need for alternative sources for powering sensors and wearable devices has led to many energy harvesting solutions by which we can consequently replace batteries. The typically small amount of energy provided needs to be efficiently managed to be able to supply biomedical applications. In biomedical sector, continuous power requirement is crucial. Available human energies can be utilized for this purpose. But as only small and limited energies can be extracted from human body, the main challenge is to enhance this low energy output with the design of proper electronic circuits to capture and increase the energy output. In a lot of cases one harvester is not sufficient. As a solution for this issue we found combinations of converters in hybrid structures an efficient technique for boosting the amount of converted energy. However, energy converters need to be designed in a proper manner fitting to the properties of ambient sources. This work reports about the design of a boost converter for an hybrid energy harvesting solution using three ambient sources, which are Radio Frequency, thermal energy and vibration for powering low power biomedical applications. In this work the use of power extracted from human body is investigated for both thermal and vibration source. The proposed boost converter is used to boost the limited input voltage from thermal, radio frequency, and vibration. The inductance in the circuit is varied from 0.3 to 1.4 μH for thermal source and from 0.10 to 0.21μH for the hybrid inputs in order to achieve the desired output range. For the hybrid structure the optimum inductance value is set to 0.21 μH to achieve the required output voltage of 3.0 to 5.5V. The converter consumes 0.28 mW of power, delivers 3.3 mW of output power, and is 91.6 % efficient for a 500 mV input. All circuits are designed and simulated using LTSPICE software.

关键词： Vibrations Inductance Wearable computers Fitting Energy harvesting Thermal energy Wearable sensors

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Design of a DC-DC Boost Converter of Hybrid Energy Harvester for IoT Devices

Design of a DC-DC Boost Converter of Hybrid Energy Harvester...

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IEEE World Forum on Internet of Things (WF-IoT)

作者： Meriam Ben Ammar Salwa Sahnoun Ahmed Fakhfakh Olfa Kanoun Measurement and Sensor Technology Chemnitz University of Technology Chemnitz Germany Digital Research Center of Sfax (CRNS) Laboratory of Technologies for smart systems (LT2S) Sfax Tunisia

ISBN: (数字)9781728155036

ISBN: (纸本)9781728155043

By energy harvesting, ambient energy from our environment can be converted into electrical energy, which can power small wireless devices and thus replacing batteries. The typically small amount of energy provided needs to be efficiently managed to be able to supply IoT devices. In a lot of cases one harvester is not sufficient. To overcome this issue energy converters need to be designed in a suitable manner fitting to the properties of ambient sources and combinations of converters in hybrid solutions can be implemented to boost the amount of converted energy. Combining different harvesters from multiple energy sources increases the reliability of the energy supply under fluctuations of ambient energy. This work reports about the design of a boost converter for an hybrid energy harvesting solution using three ambient sources, which are Radio Frequency, thermal energy and vibration for powering an IoT sensor system. The proposed boost converter is used to boost the small input voltage from thermal, radio frequency and vibration. To achieve the desired output range, the inductance in the boost converter is varied from 0.3 to 1.4μH I for thermal source and from 0.10 to 0.21 μH for the hybrid inputs. The optimum inductance value is 0.21 μH for the hybrid sources to achieve the required output voltage of 3.0 to 5.5 V. The converter consumes 0.28 mW of power, delivers 3.3 mW of output power, and is 91.6 % efficient for a 500 mV input. All circuits are designed and simulated using LTSPICE software.

关键词：

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Quantization of Acoustic Modes in Dumbbell Nanoparticles

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Physical Review Letters 2022年第4期128卷 048003-048003页

作者： Zuyuan Wang Hojin Kim Maria Secchi Maurizio Montagna Eric M. Furst Bahram Djafari-Rouhani George Fytas Max Planck Institute for Polymer Research Ackermannweg 10 Mainz 55128 Germany Institute for Measurement and Automation Division of Sensor Technology and Measurement Systems Bundeswehr University Munich Werner Heisenberg Weg 39 85579 Neubiberg Germany Department of Chemical & Biomolecular Engineering Allan P. Colburn Laboratory University of Delaware Newark Delaware 19716 USA Department of Industrial Engineering University of Trento via Sommarive 9 I-38123 Trento Italy Dipartimento di Fisica Universitá di Trento via Sommarive 14 I-38123 Trento Italy Institut d’Électronique de Microélectronique et de Nanotechnologie (IEMN) UMRCNRS 8520 Department of Physics University of Lille Villeneuve d’Ascq 59655 France

The vibrational eigenmodes of dumbbell-shaped polystyrene nanoparticles are recorded by Brillouin light spectroscopy (BLS), and the full experimental spectra are calculated theoretically. Different from spheres with a degeneracy of (2l+1), with l being the angular momentum quantum number, the eigenmodes of dumbbells are either singly or doubly degenerate owing to their axial symmetry. The BLS spectrum reveals a new, low-frequency peak, which is attributed to the out-of-phase vibration of the two lobes of the dumbbell. The quantization of acoustic modes in these molecule-shaped dumbbell particles evolves from the primary colloidal spheres as the separation between the two lobes increases.

关键词： Light-matter interaction Scattering theory Soft colloids Brillouin scattering & spectroscopy Finite-element method Inelastic light scattering

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Energy-efficient Routing of Electric Vehicles with Integrated Photovoltaic Installations

Energy-efficient Routing of Electric Vehicles with Integrate...

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IEEE Instrumentation and measurement technology Conference

作者： Christian Schuss Tapio Fabritius Bernd Eichberger Timo Rahkonen Optoelectronics and Measurement Techniques (OPEM) Research Unit University of Oulu Finland Institute of Electronic Sensor Systems Graz University of Technology Austria Circuits and Systems (CAS) Research Unit University of Oulu Finland

ISBN: (数字)9781728144603

ISBN: (纸本)9781728144610

This paper investigates the potential output power of photovoltaic (PV) installations on top of battery-powered electric vehicles (BEVs) and hybrid electric vehicles (HEVs). By choosing different routes within urban areas, we expect different output power levels from the vehicle's PV installation. Hence, we calculate energy profiles to estimate the PV energy which can be gained during driving conditions to choose the most energy-efficient route for BEVs and HEVs. While driving duration, driving distance and traffic conditions are some of the criteria within the decision-making process of routing algorithms, in this paper, we focus on energy-efficiency of routing algorithms. We present experimental data to highlight the importance of energy profiles for improving and maximising of the electrical driving distance of BEVs and HEVs.

关键词： algorithm battery-powered electric vehicle data acquisition energy profile environmental data hybrid electric vehicle measurement photovoltaic energy solar energy Hybrid electric vehicles Photovoltaic energy Energy efficiency Environmental data Electric vehicles Data Collection Methods Solar Energy Routing algorithms Installations ROADWAY-POWERED ELECTRIC VEHICLES algorithms Automobile driving Output power

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