1,720,989 research outputs found
eine Bewertung der Verwertung von Gold und Palladium
No full textDie Nachfrage nach Edelmetallen von Herstellern elektrischer und elektronischer Geräte ist in den letzten Jahren bedeutsam gestiegen. Obwohl die Edelmetallkonzentrationen in den Geräten sehr niedrig sind, sind diese Metalle wirtschaftlich und ökologisch relevant, verglichen mit anderen in höheren Konzentrationen enthaltenen Stoffen (z.B. Eisen, Kupfer, Kunststoffe). Das Ziel dieser Dissertation ist es, die Stoffflüsse von kleinen elektrischen und elektronischen Altgeräten (Kleingeräten) in Deutschland und in den USA bezogen auf das Jahr 2007 zu beschreiben, sowie die mit den Kleingeräten verbundenen Flüsse von Gold und Palladium zu quantifizieren. Obwohl Sammelsysteme für Kleingeräte existieren, werden Kleingeräte häufig nicht erfasst sondern im Restabfall entsorgt. Bezüglich der Verwertung von Kleingeräten unterscheidet das Modell Wiederverwendung und Behandlung durch den formellen und den informellen Sektor (inklusive illegalen Export von Kleingeräten). Die Stoffströme wurden, basierend auf einer Kombination von aufwendigen experimentellen Untersuchungen und Literaturauswertung, quantifiziert. Die Ergebnisse zeigen, dass 370 000 bis 430 000 Tonnen von Kleingeräten 2007 in Deutschland angefallen sind. Sie beinhalteten 1,9 bis 2,4 Tonnen Gold und 580 bis 720 kg Palladium. In den USA befanden sich in den 2007 angefallenen 3,1 bis 4,3 Million Tonnen Altgeräten 26 bis 36 Tonnen Gold und 9 bis 12 Tonnen Palladium. In Deutschland sind die Sammelquoten deutlich höher (77%) als in den USA (30%). In den USA wurden 6% der angefallenen Kleingeräte wieder verwendet, während die Wiederverwendungsquote in Deutschland 3% beträgt. 72% des in den Kleingeräten beinhalteten Goldes ging deshalb für die Kreislaufwirtschaft verloren. Die Verlustquote beträgt in den USA ca. 75%. Der wirtschaftliche Wert des verlorenen Goldes und Palladium betrug 2007 34 bis 44 Million US-Dollar in Deutschland und 466 bis 714 Million US-Dollar in den USA. Die Recyclinginfrastrukturen in Deutschland und in den USA ermöglichen keine effiziente Rückgewinnung der Edelmetalle. Die Verluste werden durch die nicht-getrennte Erfassung der Kleingeräte und durch die ungeeignete Behandlung, insbesondere bei der Aufbereitung, verursacht. Die Charakteristika der Kleingeräte beeinflussen stark die Rückgewinnung der Edelmetalle. Das soll bei der Entwicklung von Verbesserungsstrategien betrachtet werden. Neben Empfehlungen zur Systemverbesserung wurden Vorschläge zur Verbesserung der Datenerfassung zur Durchführung weiterer Stoffflussanalysen formuliert. Die angewandte Methode kann benutzt werden, um Abfallwirtschaftsysteme zu bewerten und Verbesserungsstrategien zu entwickeln. Die Methode ist nicht nur für die Bewertung der Verwertung von Wertstoffen nützlich, sondern ermöglicht im Allgemeinen eine quantitative Analyse des Verbleibs der in einem Abfallmanagementsystem behandelten Stoffe.The demand for precious metals by manufacturers of electrical and electronic equipment has increased significantly over the past few years. Although precious metal concentrations in appliances are very low, these metals have a high economic and environmental relevance compared to other substances present at much higher levels (for example iron, copper, plastics). This thesis aims at describing and quantifying the flows of small waste electrical and electronic equipment (sWEEE) in Germany and in the USA for the year 2007, as well as the flows of gold and palladium associated with the sWEEE. Although collection systems have been set up, in many cases sWEEE is not collected separately for recycling but instead is disposed of. Regarding treatment of sWEEE, the model differentiates between reuse and treatments carried out by the formal and informal sector (including illegal export of sWEEE). The material flows were quantified based on a combination of expansive experimental investigations and a review of the relevant literature. The results revealed that, in 2007, 370 000 to 430 000 tonnes of sWEEE were generated in Germany, containing 1.9 to 2.4 tonnes of gold and 580 to 720 kg of palladium. In the USA, 26 to 36 tonnes of gold and 9 to 12 tonnes of palladium were contained in the 3.1 to 4.3 million tonnes of sWEEE generated in 2007. In Germany, the collection rates are much higher (77% of the generated sWEEE is collected) than in the USA (30%). In the USA, 6% of the generated sWEEE is reused, whereas in Germany the reuse rate amounts to 3%. 72% of the gold contained in the sWEEE was discarded in Germany and therefore lost for the recycling economy. The discarding rate is around 75% for the USA. The economic value of the discarded gold and palladium in 2007 amounted to 34 to 44 million US-dollars in Germany and 466 to 714 million US-dollars in the USA. In conclusion, the recycling infrastructures in Germany and in the USA do not allow an efficient recovery of the precious metals. The losses are caused by the non-separated collection of sWEEE and by inappropriate treatment, for instance during pre-processing. The characteristics of the different types of sWEEE considerably influence the recovery of precious metals. This has to be considered by developing strategies to improve it. Besides the recommendations how to improve the system, some suggestions to improve the data collection for the conduction of further substance flow analyses were formulated. The applied methodology can be used to assess waste management systems and develop improvement strategies. The method is not only useful for assessing the recovery of valuable substances as presented in this thesis, but in a more general way allows a quantitative analysis of the destination of substances fed into a waste management system
Small - but rich in precious resources
No full textS.46-51Globally, sales of mobile phones and smartphones reached 1.55 billion units in 2011. The manufacturing of mobile phones and other small electronic devices creates a large demand for metals frequently considered as "critical". "Recycling" as a supply strategy requires, in the first instance, an efficient collection infrastructure - but this has yet to be implemented in most countries. Researchers from Berlin's University of Technology (TU Berlin) have been assessing the present situation and are proposing concepts to improve the collection of small devices.9Novembe
Environmental Sizing of Batteries for Smartphones
Full text linkSmartphone use has increased at a phenomenal pace worldwide. In 2011 more smartphones have been sold than desktop pc’s, notebooks, netbooks and tablets together. The total worldwide smartphone sales reached 472 million units in 2011, and 149 million of them were sold in the fourth quarter of 2011. The smartphone is, like almost every other mobile device, powered by batteries, limited in size and therefore capacity, which makes energy management paramount. While global demand and use of mobile devices continuously expands, the energy density of smartphone batteries has grown at an insignificant rate, but the use period still decreases because of high loads and big screens. In this paper we have studied the power breakdown of five smartphones on sale in 2011. We have defined three different user profiles for “heavy”, “moderate” and “light” users and we can state that theoretically it is sensible to re-size the battery based on the user profile. While keeping the user period acceptable we can decrease the battery capacity for moderate and light users with 25%, reducing the worldwide energy needed to product smartphone batteries with 2.1 to 3.4PJ per year. In practice the aging of the battery will result in a decreasing battery capacity over its life. When taking this into account most batteries comply with the moderate users and only a resizing strategy for the light users is sensible. This will account for only 20% of all users and can result in a worldwide decrease of energy needed for producing the smartphone batteries with 0.5 to 0.9PJ
Electronics Goes Green 2012+. Proceedings. CD-ROM
No full textUnder the slogan "Taking Green to the Next Level", the Electronics Goes Green 2012+ brings together differing perspectives, from driving change to being driven, from advancing political goals to scientific moderation of what really constitutes environmental progress
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
LCA for Green System Design of Digital Media
No full textInterest in the environmental impact from the sector of information and communication technology (ICT) is growing. A significant part of ICTs are digital media services. In order to reduce their negative environmental impacts, the design of such systems needs to take sustainability goals into account. One important tool which can support green system design is life cycle assessment (LCA) which is a well-established methodology in other sec- tors of the economy. However, a variety of properties distinguish digital media systems from traditional product systems. We review those differences and challenges to the application of LCAs to green system design of digital media products and present a case study of green system design from a large online newspaper
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
- …
