Search results for "F.E.M."
showing 10 items of 123 documents
Airborne measurements of dust layer properties, particle size distribution and mixing state of Saharan dust during SAMUM 2006
2009
The Saharan Mineral Dust Experiment (SAMUM) was conducted in May/June 2006 in southern Morocco. As part of SAMUM, airborne in situ measurements of the particle size distribution in the diameter range 4 nm < Dp < 100 μm were conducted. The aerosol mixing state was determined below Dp < 2.5 μm. Furthermore, the vertical structure of the dust layers was investigated with a nadir-looking high spectral resolution lidar (HSRL). The desert dust aerosol exhibited two size regimes of different mixing states: below 0.5 μm, the particles had a non-volatile core and a volatile coating; larger particles above 0.5 μm consisted of non-volatile components and contained light absorbing material. In…
Size distribution, mass concentration, chemical and mineralogical composition and derived optical parameters of the boundary layer aerosol at Tinfou,…
2009
During the SAMUM 2006 field campaign in southern Morocco, physical and chemical properties of desert aerosols were measured. Mass concentrations ranging from 30 Ã�¼g m-3 for PM2.5 under desert background conditions up to 300,000 Ã�¼g m-3 for total suspended particles (TSP) during moderate dust storms were measured. TSP dust concentrations are correlated with the local wind speed, whereas PM10 and PM2.5 concentrations are determined by advection from distant sources. Size distributions were measured for particles between 20 nm and 500 Ã�¼m diameter (parameterizations are given). Two major regimes of the size spectrum can be distinguished. Smaller than 500 nm particle diameter, the distrib…
Saharan dust absorption and refractive index from aircraft-based observations during SAMUM 2006
2009
During the Saharan Mineral Dust Experiment (SAMUM) conducted in summer 2006 in southeast Morocco, the complex refractive index of desert dust was determined from airborne measurements of particle size distributions and aerosol absorption coefficients at three different wavelengths in the blue (467 nm), green (530 nm) and red (660 nm) spectral regions. The vertical structure of the dust layers was analysed by an airborne high spectral resolution lidar (HSRL). The origin of the investigated dust layers was estimated from trajectory analyses, combined with Meteosat 2nd Generation (MSG) scenes and wind field data analyses. The real part n of the dust refractive index was found almost constant w…
Different scenarios of electric mobility: Current situation and possible future developments of fuel cell vehicles in Italy
2020
The diffusion of electric vehicles in Italy has started but some complications weight its spread. At present, hybrid technology is the most followed by users, due particularly to socioeconomic factors such as cost of investment and range anxiety. After a deep discussion of the Italian scenario, the aim of the paper is to recognize whether fuel cell technology may be an enabling solution to overcome pollution problems and respect for the environment. The opportunity to use fuel cells to store electric energy is quite fascinating&mdash
Displaced desires : the dislocated self and melancholic desire in Chuang Hua's Crossings and Fae Myenne Ng's Steer toward rock
2015
This essay investigates two aesthetically innovative Chinese American prose narratives, Crossings (1968) by Chuang Hua and Steer Toward Rock (2008) by Fae Myenne Ng, which have so far inspired relatively few scholarly readings. Although published forty years apart, both texts convey a melancholic image of displaced desires—loved ones who are lost, beyond reach, or unresponsive—that is echoed by their complex narrative structure and rich stylistic repertoire. Drawing from the psychoanalytically informed notion of racial melancholia, this essay argues that in Chuang’s Crossings and in Ng’s Steer Toward Rock the dynamics of melancholia manifest most prominently in the ways their dislocated cha…
Counterexamples to the Kneser conjecture in dimension four.
1995
We construct a connected closed orientable smooth four-manifold whose fundamental group is the free product of two non-trivial groups such that it is not homotopy equivalent toM 0#M 1 unlessM 0 orM 1 is homeomorphic toS 4. LetN be the nucleus of the minimal elliptic Enrique surfaceV 1(2, 2) and putM=N∪ ∂NN. The fundamental group ofM splits as ℤ/2 * ℤ/2. We prove thatM#k(S 2×S2) is diffeomorphic toM 0#M 1 for non-simply connected closed smooth four-manifoldsM 0 andM 1 if and only ifk≥8. On the other hand we show thatM is homeomorphic toM 0#M 1 for closed topological four-manifoldsM 0 andM 1 withπ 1(Mi)=ℤ/2.
Revenue models, in-app purchase, and the app performance: Evidence from Apple's App Store and Google Play
2016
The effect of revenue models on app performance depends on the app store.The effect of in-app purchase on app performance depends on the app store.Paid, freemium and in-purchase models are shown to be effective in app store.Freemium and in-app purchase models are shown to be less effective in Google Play.App category influences the effects of both revenue models and in-app purchase. In this paper, we empirically examine how the revenue model (paid, free, or freemium) adopted for a given app affects the app revenue performance as measured by the app daily revenue rank. We also study the impact of in-app purchase on this measure of performance. Moreover, we study how such relationships are co…
Abstraktās nozīmes reprezentācijas atvasināšana no esošajiem sintaktiskajiem un semantiskajiem attēlojumiem Latviešu valodā
2020
Dabiskās valodas automatizētas sapratnes risinājumi ir aktuāli un tiek izmantoti ikdienā: liela apjoma teksta analīzē, informācijas izguvē un strukturēšanā, mediju un sociālo tīklu monitoringā u.c. Šo risinājumu implementācija balstās uz teksta semantiskajiem parsētājiem, kuru mašīnapmācībai nepieciešamas lielas, formāli anotētas datu kopas (valodas resursi). Viens no pēdējos gados plašāk pētītajiem teksta semantiskā attēlojuma formālismiem ir Abstraktā nozīmes reprezentācija (AMR). Latviešu valodai ir pieejami vairāki sintaktiski un semantiski anotēti valodas resursi, taču pašlaik vēl nav pieejama apjomīga, kvalitatīvi anotēta latviešu valodas AMR treniņdatu kopa. Iegūt AMR treniņdatus nav…
Topological classification of gradient-like diffeomorphisms on 3-manifolds
2004
Abstract We give a complete invariant, called global scheme , of topological conjugacy classes of gradient-like diffeomorphisms, on compact 3-manifolds. Conversely, we can realize any abstract global scheme by such a diffeomorphism.
Conjugate unstable manifolds and their underlying geometrized Markov partitions
2000
Abstract Conjugate unstable manifolds of saturated hyperbolic sets of Smale diffeomorphisms are characterized in terms of the combinatorics of their geometrized Markov partitions. As a consequence, the relationship between the local and the global point of view is also made explicit.