56 research outputs found
Improving energy efficiency of machine tools
Part of:
Seliger, Günther (Ed.): Innovative solutions : proceedings / 11th Global Conference on Sustainable Manufacturing, Berlin, Germany, 23rd - 25th September, 2013. - Berlin: Universitätsverlag der TU Berlin, 2013. - ISBN 978-3-7983-2609-5 (online). - http://nbn-resolving.de/urn:nbn:de:kobv:83-opus4-40276. - pp. 125–130.Manufacturing is responsible for about one half of global consumption of primary energy, a great deal of which is consumed by machine tools producing discrete parts. The topic of energy efficiency is driven forward by machine tool users who demand low operational costs, as well as social and legislative forces requiring environmentally friendlier manufacturing. This paper aims to provide examples and good practices for improving machine tool energy efficiency with a focus on metal cutting machine tools. During the design stage, there are various opportunities to minimize inherent energy losses by selecting and dimensioning drives and peripherals. On the other hand, users have a large impact on productivity by using the machine effectively and knowledgeably. The paper also presents techniques for measurement and analysis of the energy profile of machines which help to better target energy saving measures on already existing machines
Number Concentrations and Modal Structure of Indoor/Outdoor Fine Particles in Four European Cities
Indoor/outdoor aerosol size distribution was measured in four European cities (Oslo-Norway, Prague-Czech Republic, Milan-Italy and Athens-Greece) during 2002 in order to examine the differences in the characteristics of the indoor/outdoor modal structure and to evaluate the effect of indoor sources to the aerosol size distributions. All the measurement sites were naturally ventilated and were occupied during the campaigns by permanent residents or for certain time periods by the technical staff responsible for the instrumentation. Outdoor particle number (PN) concentrations presented the higher values in Milan and Athens (median values 1.4 x 10(4) # cm(-3) and 2.9 x 10(4) # cm(-3) respectively) as a result of elevated outdoor emissions and led to correspondingly higher indoor values compared to Oslo and Prague. In absence of indoor activities, the indoor concentrations followed the fluctuations of the outdoor concentrations in all the measurement sites. Indoor activities (cooking, smoking, etc.) resulted in elevated indoor PN concentrations (maximum values ranging between 1.7 x 10(5) # cm(-3) and 3.2 x 10(5) # cm(-3)) and to I/O ratios higher than one. The I/O ratios were size dependant and for periods without indoor activities, they presented the lowest values for particles <50 nm (0.51 +/- 0.15) and the ratios increased with fine particle size (0.79 +/- 0.12 for particles between 100-200 nm). The analysis of the modal structure showed that the indoor aerosol size distribution characteristics differ from the outdoors under the effect of indoor sources. The percentage of unimodal size distributions increased during indoor emissions, compared to periods without indoor sources, along with the number concentration of Aitken mode particles, indicating emissions in specific size ranges according to the type of the indoor source.Peer reviewe
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Word Order and Case Inflection in Czech: On-line Sentence Comprehension in Children and Adults
Modal Structure of the Fine Urban Aerosol in four European Cities
The size distribution of the sub micrometer aerosol number concentration in the urban Environment appears to display a statistically significant modal structure (Van Dingenen et al., 2004). This depends on a number of factors such as local atmospheric conditions, density and type of emissions. The development of certain "universal" aerosol number distribution patterns can contribute towards the assessment of human exposure to fine particulate matter or facilitate the characterization of certain emission sources and their impact on air quality. Here, preliminary results from the analysis of measured number size distributions are presented for four European cities.JRC.H.4-Transport and air qualit
Development and application of a comprehensive microenvironmental model for estimating indoor air quality
Μη διαθέσιμη περίληψηNot available summarizationΠαρουσιάστηκε στο: Journal of Aerosol Scienc
Dynamics of Fine Particles and Photo-oxidants in the Eastern Mediterranean (SUB-AERO)
As part of the European project SUB-AERO, comprehensive aerosol and gaseous pollutant measurement campaigns were performed at the Finokalia station (July 2000 and January 2001) on the island of Crete (Greece) in combination with boat measurements in the eastern part of the Mediterranean area. The measurements were performed with the participation of nine European research institutions. The objective of the measurement campaigns was to evaluate and assess the spatial and temporal variability of photochemical pollutants and fine particles. The current overview paper presents the framework and main results of the measurements and modelling studies performed during the project.
Extensive measurements of gaseous and atmospheric-aerosol physical, chemical and optical characteristics were performed during the measurement campaigns in conjunction with detailed chemical analyses of the aerosol species.
Along with the experimental work mesoscale modelling, using a combination of the UAM-AERO air quality model together with the RAMS prognostic meteorological model, was used to reveal the dynamics of particulate matter and
photo-oxidants. Furthermore, regional chemistry transport models were applied to determine the background and initial conditions for the mesoscale modelling.
r 2005 Elsevier Ltd. All rights reserved.JRC.H.4-Transport and air qualit
A European aerosol phenomenology – 3: Physical and chemical characteristics of particulate matter from 60 rural, urban, and kerbside sites across Europe
This paper synthesizes data on aerosol (particulate matter, PM) physical and chemical characteristics, which were obtained over the past decade in aerosol research and monitoring activities at more than 60 natural background, rural, near-city, urban, and kerbside sites across Europe. The data include simultaneously measured PM10 and/or PM2.5 mass on the one hand, and aerosol particle number concentrations or PM chemistry on the other hand. The aerosol data presented in our previous works (Van Dingenen et al., 2004; Putaud et al., 2004) were updated and merged to those collected in the framework of the EU supported European Cooperation in the field of Scientific and Technical action COST 633 (Particulate matter: Properties related to health effects). A number of conclusions from our previous studies were confirmed. There is no single ratio between PM2.5 and PM10 mass concentrations valid for all sites, although fairly constant ratios ranging from 0.5 to 0.9 are observed at most individual sites. There is no general correlation between PM mass and particle number concentrations, although particle number concentrations increase with PM2.5 levels at most sites. The main constituents of both PM10 and PM2.5 are generally organic matter, sulfate and nitrate. Mineral dust can also be a major constituent of PM10 at kerbside sites and in Southern Europe. There is a clear decreasing gradient in SO42- and NO3- contribution to PM10 when moving from rural to urban to kerbside sites. In contrast, the total carbon / PM10 ratio increases from rural to kerbside sites. Some new conclusions were also drawn from this work: the ratio between ultrafine particle and total particle number concentration decreases with PM2.5 concentration at all sites but one, and significant gradients in PM chemistry are observed when moving from North-Western, to Southern to Central Europe. Compiling an even larger number of data sets would have further increased the significance of our conclusions, but collecting all the aerosol data sets obtained also through research projects remains a tedious task.JRC.H.2-Air and Climat
DHCAL with Minimal Absorber: Measurements with Positrons
International audienceIn special tests, the active layers of the CALICE Digital Hadron Calorimeter prototype, the DHCAL, were exposed to low energy particle beams, without being interleaved by absorber plates. The thickness of each layer corresponded approximately to 0.29 radiation lengths or 0.034 nuclear interaction lengths, defined mostly by the copper and steel skins of the detector cassettes. This paper reports on measurements performed with this device in the Fermilab test beam with positrons in the energy range of 1 to 10 GeV. The measurements are compared to simulations based on GEANT4 and a standalone program to emulate the detailed response of the active elements
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