Now showing 1 - 10 of 170
  • Publication
    Ecological Cost-Benefit Analysis of a Sensor-Based Parking Prediction Service
    ( 2021)
    Druschke, J.
    ;
    Fath, S.
    ;
    Stobbe, L.
    ;
    Nissen, N.F.
    ;
    Richter, N.
    ;
    Lang, K.-D.
    The fast-growing sector of smart city applications resulting from the ongoing digitalization has a huge impact on our society. They use innovative technologies to improve for example mobility, optimize shopping or offer intelligent travel guide assistance. However, these applications have not only the potential to benefit our daily life with precisely targeted services, but also to reduce the environmental impact we create. In this paper the authors present the proceeding for a simplified life cycle assessment on the special case of a sensor-based parking prediction service of the Deutsche Telekom called "Park&Joy".
  • Publication
    Methodology for Modeling the Energy and Material Footprint of Future Telecommunication Networks
    ( 2021)
    Stobbe, L.
    ;
    Nissen, N.F.
    ;
    Druschke, J.
    ;
    Zedel, H.
    ;
    Richter, N.
    ;
    Lang, K.-D.
    This paper presents important methodical aspects in conjunction with the ongoing development of a novel multi-level-model in support of lifecycle environmental assessments of telecommunication networks. The new approach is, to some extent, emulating the OSI-layer model (Open Systems Interconnection), starting at the bottom with the main physical components, followed by product configurations, network architecture and control. On the top layer, the model scales through application and use case scenarios. This complex inventory model furthermore distinguishes between constructive (hardware-defined) elements on the one hand and operational (software-defined) elements on the other. By combining technical data as fixed values with application data as variable values, it is now possible to analyze the causal interaction between different technology generations, network configurations, and utilization intensity. It will allow identifying the best starting point for eco-design and improvement measures. Due to fact that the new methodology is not limited to energy consumption only, it supports a holistic understanding of the environmental impact of telecommunication networks.
  • Publication
    Recyclability of tungsten, tantalum and neodymium from smartphones
    ( 2021)
    Nissen, N.F.
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    Reinhold, J.
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    Schischke, K.
    ;
    Despite increasing pressure to reduce the consumption of critical resources, a number of highly relevant elements are still not being recycled from electronics, or only in the few applications, where they are used in bigger units. In high volume products and particular mobile products such as smartphones the content of these materials is low per unit, but still a large quantity when multiplied with millions of units shipped per year. The sustainably SMART projects explores the option to separate components containing tantalum, neodymium and tungsten from disassembled smartphones as these metals are lost in conventional electronics waste recycling processes. In this paper the target components are tantalum capacitors, loudspeakers, and vibration motors. Example quantities per device are explored and mirrored against current and potential recycling processes.
  • Publication
    Metallic Interconnection Technologies for High Power Vertical Cavity Surface Emitting Lasers Modules
    Highly reliable power VCSEL (Vertical Cavity Surface Emitting Lasers) array systems with an optimized optical output require a plan parallel assembly for a homogeneous radiation and an advanced packaging design to ensure good heat dissipation and an overall reliable performance. The aim of this study is to evaluate if metallic interconnection technologies like soldering and silver sintering can meet these requirements. Therefore, GaAs dies with VCSEL arrays of more than 2000 single lasers were mounted on substrates by soldering using AuSn20 and SnAg3 solder as well as by applying pressure assisted silver sintering. The samples were analyzed using ultrasonic microscopy (C-SAM), X-ray microscopy and 3D laser profilometry. Cross-sections of selected samples were made and analyzed using light- and scanning electron microscopy (SEM). Soldered and silver sintered samples were subjected to thermal cycling between -55°C and +125°C to validate the reliability of the metallic interconnects. Furthermore, it was tested, if it is possible to assemble a DCB onto a micro channel water cooler made of copper by pressure assisted silver sintering in order to enable an advanced heat transfer of the high power VCSEL module.
  • Publication
    ErP - the european directive on ecodesign
    ( 2019)
    Nissen, N.F.
    This chapter gives an overview of the European Ecodesign Regulation for energy-related Products (ErP). This is helpful in order to highlight different regulatory approaches compared to waste electrical and electronic equipment (WEEE) and to show the potentials for collaboration or for conflicts between the two regulations.
  • Publication
    Reduction of hazardous materials in electrical and electronic equipment
    ( 2019)
    Deubzer, O.
    Electrical and electronic equipment (EEE), in addition to including precious and other valuable and scarce metals, contains toxic substances. Starting at the turn of the 21st century, governments began to legally restrict the use of well-known hazardous substances such as lead, cadmium, mercury, and hexavalent chromium. The templates for such various legislations worldwide is European Restriction of Hazardous Substances (RoHS) Directive 2011/65/EU and Restriction, Evaluation, Authorisation and Restriction of Chemicals Regulation (EC) No 1907/2006. Restrictions on lead, cadmium, hexavalent chromium, and mercury have considerably reduced the amounts of these substances used in EEE since 2006. Nevertheless, due to exemptions, several thousand tonnes of lead, as well as other restricted substances, are still used in new EEE. The RoHS directive has considerably reduced EEE toxicity. E-waste is increasingly generated in developing countries and countries with market economies in transition. At the same time, these countries are the target of e-waste exports from developed countries, mostly in combination with used electrical and electronic equipment. Hazardous substances in EEE cause extensive damage in these countries due to inappropriate treatment at end of life. Even though the substitution of hazardous substances in EEE can make sense, the example of lead substitution reveals that a simple ban-and-chase policy for complex products such as EEE may provoke manifold unwanted environmental and economic side effects. A more differentiated and holistic approach is therefore necessary, one that accounts for the actual environmental and health risks related to the use of hazardous substances compared with their substitutes, as well as more eco-efficiency-oriented measures to achieve a result that contributes to sustainable development.
  • Publication
    Adaptives Low-Power Sensor- und Funknetzwerk für Assistenzsysteme im Bereich altersgerechtes Wohnen (ALFA)
    ( 2018)
    Al-Batol, Muaadh
    ;
    Bickel, Jan
    ;
    Ngo, Ha Duong
    Unter dem Schlagwort Ambient Assisted Living (AAL), zu Deutsch altersgerechte Assistenzsysteme, werden Technologien und Systeme aufgeführt, die es unserer alternden und zunehmend digitalisierten Gesellschaft heute und in der Stadt der Zukunft es ermöglichen sollen ein langes, selbstbestimmtes Leben zu führen. Für die Kommunikation dieser Hilfssysteme ist eine drahtlose Übertragung von Daten und Informationen unausweichlich. Dafür benötigen alle dieser uns umgebenden und unterstützenden Informations- und Kommunikationstechnologien [01] (IKT) elektrische Energie und müssen für den geringsten möglichen Energiebedarf entwickelt und optimiert werden. Viele Anwendungen, die in ihrem Wesen autark sind, müssen sich von der klassischen Energiezufuhr lösen und die für ihre Funktion notwendige elektrische Energie unmittelbar aus ihrer Umgebungsenergie gewinnen können - Energy Harvesting. Die IKT-Komponenten im Bereich Ambient Assisted Living (Embedded Systems, Funkmodule, Sensoren etc.) müssen für einen anwendungsgebundenen, unstetigen und schwachen Energiefluss, auch durch Energy Harvesting, der aber ihre Funktionalität dennoch sichern könnte, ausgelegt werden. Günstige, energiesparsame drahtlose Knoten solcher drahtlosen Sensornetzwerke (WSN - Wireless Sensor Networks) mit entsprechender Skalierbarkeit und funktionaler Flexibilität gilt es zu entwickeln [02].
  • Publication
    Silicon micro piezoresistive pressure sensors
    Of all micro sensors the silicon pressure sensors have the largest market potential. It will remain a stable growth market over the next years. The value of the MEMS pressure sensor market is big. The market will grow from $1.9 billion in 2012 to $ 3 billion in 2018 [1]. Many companies offer them for a large number of applications, such as automotive, industrial, consumer, medical and high-end. The sensors differ in their specifications, their type of packaging and signal processing, and also their price. The manufacturers often offer a large variety of products ranging from sensor chips over OEM products to complete sensors (transmitters) with media separation, signal processing, and temperature compensation. In this chapter firstly the physical principle, which is suitable for pressure sensing is presented, followed by state of the art of silicon piezoresistive pressure sensors is described.
  • Publication
    Piezoresistive pressure sensors for applications in harsh environments - a roadmap
    Piezoresistive mechanical sensors play a very important role in modern industries. MEMS pressure sensor market is one of the biggest markets among all MEMS components [1]. Global pressure sensor market is growing from $6.4 billion in 2012 to $8.8 billion in 2018. The main applications are automotive, medical, consumer electronics, industry and aerospace/defense. Today, there is a growing demand for cost effective high-temperature and harsh- environment semiconductor devices, capable of operating at temperatures in the 500 °C range. Developments in energy, aircraft and space applications, automotive electronics, the oil and gas industry, the plastic and chemical industry, and the military sector are among the main drivers for research on high-temperature sensors and electronics. Existing semiconductor devices based on silicon are limited to operating temperatures below 150 °C, as thermal generation of charge carriers severely degrades device operation at higher temperatures. The development of SOI (silicon on insulator) technology helped to extend device's operating temperatures to approximately 400 °C. However, at temperatures over 400 °C, the material silicon reaches its physical limits as plastic deformation starts to occur when mechanical stress is applied. Silicon carbide is considered to be the most promising semiconductor for future high-temperature and harsh-environment applications as it features a unique combination of favorable physical, electrical, mechanical, and chemical properties. It is an extremely hard and robust material with a high thermal stability, and is chemically inert up to temperatures of several hundred degrees. Moreover, it has a higher thermal conductivity than copper, and its wide energy bandgap allows operation at high temperatures and in high radiation environments without suffering from intrinsic conduction effects. Performance and reliability of metal-semiconductor contacts, conducting paths and the capability of etching 3D mechanical structures in SiC (such membrane or bridge) remain limiting factors for high-temperature operation of SiC electronic mechanical sensors today. In this chapter we discuss and review materials (Silicon, pSOI, SOI, 3C-SiC and 4H/6H-SiC) and technologies, which are applicable to realize MEMS piezoresistive mechanical sensor elements for applications at elevated temperatures.