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81.
Annukka Santasalo-Aarnio Maryam Borghei Ilya V. Anoshkin Albert G. Nasibulin Esko I. Kauppinen Virginia Ruiz Tanja Kallio 《International Journal of Hydrogen Energy》2012
PtRu catalysts with similar particle size and composition were deposited on three different carbon supports: Vulcan, graphitized carbon nanofibers (GNF) and few-walled carbon nanotubes (FWCNT) and their performance for methanol oxidation was studied in an electrochemical cell and in a single cell DMFC. The electrochemical results indicate that with PtRu/GNF and PtRu/FWCNT higher current densities are obtained and oxidation intermediates deactivate the surface less compared to the same catalyst on Vulcan support. Conversely, PtRu/Vulcan provided the highest open circuit voltage OCV and current densities in DMFC experiments due to a well-optimized electrode layer structure. Because stability is a key requirement for fuel cell commercialization, 6-day-long fuel cell stability tests were carried out, showing that PtRu/Vulcan degraded significantly. This was due to the collapse of the secondary structure of the electrode layer revealed by post characterization of the membrane electrode assembly (MEA) with SEM and TEM. PtRu/GNF exhibited slightly poorer initial performance but better stability because the structure of the anode layer was maintained. PtRu/FWCNT showed the worst initial performance and long-term stability. The good stability of non-optimized PtRu/GNF MEAs shows the potential of these novel nanocarbon supported catalysts as stable fuel cell components after proper MEA optimization. 相似文献
82.
In the near future,there will be many more embedded devices than there are mobile phones.When these devices are connected to the Internet,many novel kinds of ubiquitous service will be enabled. 相似文献
83.
Olivia Langhamer Kalle Haikonen Jan Sundberg 《Renewable & Sustainable Energy Reviews》2010,14(4):1329-1335
Generating electricity from waves is predicted to be a new source of renewable energy conversion expanding significantly, with a global potential in the range of wind and hydropower. Several wave power techniques are on the merge of commercialisation, and thus evoke questions of environmental concern. Conservation matters are to some extent valid independent of technique but we mainly focus on point absorbing linear generators. By giving examples from the Lysekil project, run by Uppsala University and situated on the Swedish west coast, we demonstrate ongoing and future environmental studies to be performed along with technical research and development. We describe general environmental aspects generated by wave power projects; issues also likely to appear in Environmental Impact Assessment studies. Colonisation patterns and biofouling are discussed with particular reference to changes of the seabed and alterations due to new substrates. A purposeful artificial reef design to specially cater for economically important or threatened species is also discussed. Questions related to fish, fishery and marine mammals are other examples of topics where, e.g. no-take zones, marine bioacoustics and electromagnetic fields are important areas. In this review we point out areas in which studies likely will be needed, as ventures out in the oceans also will give ample opportunities for marine environmental research in general and in areas not previously studied. Marine environmental and ecological aspects appear to be unavoidable for application processes and in post-deployment studies concerning renewable energy extraction. Still, all large-scale renewable energy conversion will cause some impact mainly by being area demanding. An early incorporation of multidisciplinary and high quality research might be a key for new ocean-based techniques. 相似文献
84.
85.
Brian Fildes Michael Keall Pete Thomas Kalle Parkkari Lucia Pennisi Claes Tingvall 《Accident; analysis and prevention》2013
Real-world retrospective evaluation of the safety benefits of new integrated safety technologies is hampered by the lack of sufficient data to assess early reliable benefits. This MUNDS study set out to examine if a “prospective” case-control meta-analysis had the potential to provide more rapid and rigorous analyses of vehicle and infrastructure safety improvements. To examine the validity of the approach, an analysis of the effectiveness of ESC using a consistent analytic strategy across 6 European and Australasian databases was undertaken. It was hypothesised that the approach would be valid if the results of the MUNDS analysis were consistent with those published earlier (this would confirm the suitability of the MUNDS approach). The findings confirm the hypothesis and also found stronger and more robust findings across the range of crash-types, road conditions, vehicle sizes and speed zones than previous. The study recommends that while a number of limitations were identified with the findings that need be addressed in future research, the MUNDS approach nevertheless should be adopted widely for the benefit of all vehicle occupants. 相似文献
86.
Information System Development (ISD) agility is concerned with why and how ISD organizations sense and respond swiftly as they develop and maintain Information System applications. We outline a theory of ISD agility that draws upon a model of IT innovation and organizational learning. The theory adopts March's concepts of exploration and exploitation to investigate agility in the context of ISD organizations. Depending on their learning focus, ISD organizations make choices as to what sensing and responding swiftly means. This is reflected in how they value speed in relation to other ISD process goals, including quality, cost, risk and innovative content. The paper examines two specific Research Propositions: (1) ISD organizations locate themselves into different innovation regimes with respect to their need for exploration and exploitation, and (2) their perceptions of agility differ in those regimes as reflected in their process goal priorities. We validate these propositions through an empirical investigation of changes in ISD organizations' process goals and innovation practices over a period of over 4 years (1999–2003), during which time they shied away from exploration to exploitation while innovating with Internet computing. These ISD organizations viewed agility differently during the studied time periods as reflected in how they traded innovative content or speed vis-à-vis the other process goals of cost, risk, and product quality. In conclusion, this paper discusses implications for future research on agility in ISD organizations. 相似文献
87.
H. Kallio T. Lehtinen P. Laakso R. Tahvonen 《European Food Research and Technology》1998,207(4):276-280
The fatty acid composition of "fish wurst", a fermented salami-type sausage made of pork, lard and Baltic herring fillets
(Clupea harengus var. membras) was investigated. Changes in the proportions of the 35 most abundant fatty acids were examined throughout the 1-month ripening
period followed by a 4-month storage period. The fat composition of the product was stable (32–35%) and retained the characteristics
of the main ingredients: oleic acid (37.4%, mean of three production batches) palmitic acid (23.7%) and linoleic acid (10.7%)
from lard and fish, stearic acid (11.7%) mainly from lard, and palmitoleic acid (3.0%) and long-chain (C20–C24), polyunsaturated
fatty acids (c.a. 6%) mainly from fish. During the 4-week ripening period a statistically significant increase (P≤0.05) was detected in the proportions of minor fatty acids only, i.e. eicosenoic acid (20 : 1n-9), eicosadienoic acid (20 : 2n-6),
docosadienoic acid (22 : 2n-6) and docosatrienoic acid (22 : 3n-3). During the 4-month storage of the ripe sausage, the fatty
acid composition stabilized. Only the proportion of stearic acid increased significantly during storage, from 11.7% to 12.5%.
Received: 23 January 1998 / Revised version: 1 April 1998 相似文献
88.
We define an operation called transposition on words of fixed length. This operation arises naturally when the letters of a word are considered as entries of a matrix. Words that are invariant with respect to transposition are of special interest. It turns out that transposition invariant words have a simple interpretation by means of elementary group theory. This leads us to investigate some properties of the ring of integers modulo n and primitive roots. In particular, we show that there are infinitely many prime numbers p with a primitive root dividing p+1 and infinitely many prime numbers p without a primitive root dividing p+1. We also consider the orbit of a word under transposition. 相似文献
89.
PD Dr. med. Dr. phil. Eva C. Winkler Dr. PH Dominik Ose Prof. Dr. med. Hanno Glimm Prof. Dr. theol. Klaus Tanner Prof. Dr. med. Christof von Kalle 《Ethik in der Medizin》2013,25(3):195-203
Definition of the problem Breakthrough discoveries in genomics allow the sequencing of the human genome within a couple of days at a reasonable price. In cancer research, whole genome sequencing helps to identify the molecular lesions that drive tumour growth and thereby provide the basis for the development of targeted therapies. However, genomic research also raises new ethical questions. The interdisciplinary EURAT project in Heidelberg (Germany) addresses these normative questions. It aims at developing an ethically and legally informed practice for biobank-based genomic research in Heidelberg. Arguments This paper gives an overview of the relevant ethical and clinical questions of biobank-based genomic sequencing with regard to the informed consent process. It also presents a code of conduct as an institutional ethics response to the following question: how research institutions can foster the responsible handling of genetic information in biobank-based research throughout the institution. Conclusion A thorough informed consent process and the code of conduct are elements of a best-practice guideline and should be a guide for responsible conduct of all employees who handle sensitive genetic data. 相似文献
90.
Abstract. This paper identifies factors that affected over 200 information system (IS) process innovation adoption decisions in three organizational environments over a period that spanned four decades. The analysis is based on Rogers's (1995) theory of Diffusion of Innovations (DOI). The results show that several DOI factors strongly affect IS process innovation adoption. These include user need recognition, availability of technological infrastructure, past experience, own trials, autonomous work, ease of use, learning by doing and standards. Yet, a large number of IS process innovation adoptions followed no discernible pattern. 相似文献