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21.
On-road emissions of light-duty vehicles in europe 总被引:1,自引:0,他引:1
Weiss M Bonnel P Hummel R Provenza A Manfredi U 《Environmental science & technology》2011,45(19):8575-8581
For obtaining type approval in the European Union, light-duty vehicles have to comply with emission limits during standardized laboratory emissions testing. Although emission limits have become more stringent in past decades, light-duty vehicles remain an important source of nitrogen oxides and carbon monoxide emissions in Europe. Furthermore, persisting air quality problems in many urban areas suggest that laboratory emissions testing may not accurately capture the on-road emissions of light-duty vehicles. To address this issue, we conduct the first comprehensive on-road emissions test of light-duty vehicles with state-of-the-art Portable Emission Measurement Systems. We find that nitrogen oxides emissions of gasoline vehicles as well as carbon monoxide and total hydrocarbon emissions of both diesel and gasoline vehicles generally remain below the respective emission limits. By contrast, nitrogen oxides emissions of diesel vehicles (0.93 ± 0.39 grams per kilometer [g/km]), including modern Euro 5 diesel vehicles (0.62 ± 0.19 g/km), exceed emission limits by 320 ± 90%. On-road carbon dioxide emissions surpass laboratory emission levels by 21 ± 9%, suggesting that the current laboratory emissions testing fails to accurately capture the on-road emissions of light-duty vehicles. Our findings provide the empirical foundation for the European Commission to establish a complementary emissions test procedure for light-duty vehicles. This procedure could be implemented together with more stringent Euro 6 emission limits in 2014. The envisaged measures should improve urban air quality and provide incentive for innovation in the automotive industry. 相似文献
22.
Lopez Daniel Andres Sanchez Chagas Luciana Gomes Batista Aline Domingues Guaita Maria Gabriella Detone Amorin Luís Henrique Cardozo da Silva Paulo Rogério Catarini Yamanishi Gustavo Zaia Dimas Augusto Morozin de Santana Henrique Urbano Alexandre 《Journal of Materials Science: Materials in Electronics》2021,32(13):17462-17472
Journal of Materials Science: Materials in Electronics - The increasing demand for lithium-ion batteries has stimulated the investigation of new compounds in order to reduce the costs and the... 相似文献
23.
Exploring farmer's knowledge as a source of information on past and present cultural landscapes: A case study from NW Spain 总被引:5,自引:2,他引:3
The primary goal of this research was to explore the potential of farmer's knowledge as a source of information on the past and present cultural landscapes, focusing on the land-use system, the cultural heritage, and the farmer's perception of landscape changes, from the 1950s to the present day. For this purpose, 42 semi-structured interviews were conducted from a random sample of 10% of the villages in an area of the Northern Mountains of Galicia (NW Spain). As shown in farmers’ reports, the main crops in the 1950s were wheat or rye, potatoes or maize (only near the coast) and turnips. Scrubland areas were an essential resource for pasture, litter, temporary crops and charcoal, whereas deciduous forest was mainly used as a source of wood for carpentry, firewood and litter. Agriculture was the main economic activity, whereas crafts and other activities in the fisheries or forestry industry were secondary. Granaries, watermills and stone laundry basins were the most frequent elements of built heritage that was mentioned in the interviews. Farmers were also comprehensively aware of the broad changes that occurred in the landscape. The results indicate that farmer's knowledge is a valuable source of information for documenting past and present land-use practices, local cultural heritage and changes in the landscape, all of which are helpful for the design of landscape-orientated policies. Moreover, observed ancestral cultural practices, such as extensive grazing in scrubland areas, may be promoted as strategies for helping the sustainability of cultural landscapes in the study area and in other areas with similar characteristics. 相似文献
24.
With video-on-demand (VoD) regarded as one of the drivers for the deployment of broadband integrated service digital networks (B-ISDNs), an important issue is how to provide wide area VoD services most efficiently. A large contributor to the cost of a VoD system is storage. The nature of the service requires massive amounts of storage and bandwidth to be supplied from a video server located within the network. We examine the costs of storage in such servers and develop an efficient allocation scheme designed to minimize this cost. Using this scheme, centralized and distributed approaches to VoD are compared. We conclude that a distributed approach to storage costs no more than a centralized approach and offers considerable advantages in terms of bandwidth requirements and service quality 相似文献
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Pedro J. Rivera Torres Eileen I. Serrano Mercado Luis Anido Rifón 《Journal of Intelligent Manufacturing》2018,29(6):1393-1413
Modeling manufacturing processes assists the design of new systems, allowing predictions of future behaviors, identifying improvement areas and evaluating changes to existing systems. Probabilistic Boolean networks (PBN) have been used to study biological systems, since they combine uncertainty and rule-based representation. A novel approach is proposed to model the design of an automated manufacturing assembly processes using PBNs to generate quantitative data for occurrence assessment in design failure mode and effects analysis. FMEA is a widely used tool in risk assessment (RA) to ensure design outputs consistently deliver the intended level of performance. Effectiveness of RA depends upon the robustness of the data used. Temporal logic is applied to analyze state successions in a transition system, while interactions and dynamics are captured over a set of Boolean variables using PBNs. Designs are therefore enhanced through assessment of risks, using proposed tools in the early phases of design of manufacturing systems. A two-sample T test demonstrates the proposed model provides values closer to expected values; consequently modeling observable phenomena (\(p\,\hbox {value} > 0.05\)). Simulations are used to generate data required to conduct inferential statistical tests to determine the level of correspondence between model prediction and real machine data. 相似文献
29.
F. J. Gonzlez‐Castao L. Anido‐Rifn J. M. Pousada‐Carballo P. S. Rodríguez‐Hernndez R. Lpez‐Gmez 《Software》2001,31(1):1-16
Virtual machines for remote execution are a useful tool for utilizing light user interfaces and intensive application cores in different physical machines connected through the Internet. In a virtual machine, application cores are distributed in a network. Specific locations, operating systems and hardware characteristics are hidden by virtual machines. They make it possible to use a PC to execute user interfaces and (a few) high‐performance computers for application cores. We present a Java/CORBA‐based brokerage platform that allows remote execution of optimization solvers from a client running on any platform. The system offers a dynamic library of available problem solvers, and a graphic interface to browse several defined properties and metadata on available solvers. In addition, an embedded file compression module to reduce data transfer time is included as a plug‐in feature of the proposed virtual machine. Analogous systems could be constructed for applications in which interaction traffic time is much lower than execution time. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
30.
Blustein David L.; Murphy Kerri A.; Kenny Maureen E.; Jernigan Maryam; Pérez-Gualdrón Leyla; Casta?eda Tani; Koepke Margaret; Land Marie; Urbano Alessandra; Davis Ophera 《Canadian Metallurgical Quarterly》2010,57(2):248
This qualitative study is an exploration of 32 urban high school students’ narratives about the connection between school, work, and societal expectations of their future success related to their racial and ethnic background. The sample varied along 2 contextual dimensions: participation in a psychoeducational intervention (Tools for Tomorrow) and developmental status (i.e., half the sample were 9th-grade students and the other half were 12th-grade students). Using consensual qualitative research, the narratives revealed 3 major domains: future orientation; students’ perceptions of society’s expectations based on race and ethnicity; and students’ perception of the role of their race and ethnicity in future success. Results reveal that the majority of students endorse a connection between school and work, believe that society holds low expectations for them based on their racial and ethnic background, and cannot predict their future success based on their background. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献