Search results for " surface"
showing 10 items of 2838 documents
On Severi Type Inequalities for Irregular Surfaces
2017
Let X be a minimal surface of general type and maximal Albanese dimension with irregularity q ≥ 2. We show that K2 X ≥ 4χ(OX) + 4(q − 2) if K2 X < 9 2 χ(OX), and also obtain the characterization of the equality. As a consequence, we prove a conjecture of Manetti on the geography of irregular surfaces if K2 X ≥ 36(q−2) or χ(OX) ≥ 8(q−2), and we also prove a conjecture that the surfaces of general type and maximal Albanese dimension with K2 X = 4χ(OX) are exactly the resolution of double covers of abelian surfaces branched over ample divisors with at worst simple singularities.
State and parameter update in a coupled energy/hydrologic balance model using ensemble Kalman filtering
2012
Summary The capability to accurately monitor and describe daily evapotranspiration (ET) in a cost effective manner is generally attributed to hydrological models. However, continuous solution of energy and water balance provides precise estimations only when a detailed knowledge of sub-surface characteristics is available. On the other hand, residual surface energy balance models, based on remote observation of land surface temperature, are characterised by sufficient accuracy, but their applicability is limited by the lack of high frequency and high resolution thermal data. A compromise between these two methodologies is represented by the use of data assimilation scheme to include sparse …
Janus Micelles Induced by Olefin Metathesis
2008
A facile one-step procedure for hydrophobic modification and simultaneous TEM contrast enhancement via a regioselective olefin metathesis reaction using Grubbs' catalyst is presented. Polyether diblock copolymers were investigated, and both the chain ends of the hydrophilic and the hydrophobic block were hydrophobically modified. Modification of the hydrophilic block results in nonsymmetric supramolecular structures (Janus micelles) which self-assemble into larger hierarchically organized super-micelles.
Conical Two-Phase Swirl Flow Atomizers—Numerical and Experimental Study
2021
This paper presents the results of numerical simulations for the developed and discussed conical two-phase atomizers with swirl flow, differing in the ratio of the height of the swirl chamber to its diameter. Experiments were carried out for SAN-1 with HS/DS = 1 and SAN-2 with HS/DS = 4 atomizers. The study was conducted over a range of Reynolds number for liquid ReL = (1400
Optimization and sensitivity analysis of existing deep learning models for pavement surface monitoring using low-quality images
2022
Automated pavement distress detection systems have become increasingly sought after by road agencies to in crease the efficiency of field surveys and reduce the likelihood of insufficient road condition data. However, many modern approaches are developed without practical testing using real-world scenarios. This paper ad dresses this by practically analyzing Deep Learning models to detect pavement distresses using French Secondary road surface images, given the issues of limited available road condition data in those networks. The study specifically explores several experimental and sensitivity-testing strategies using augmentation and hyper- parameter case studies to bolster practical mode…
Observed changes in the life time and amplitude of the madden-julian oscillation associated with interannual ENSO sea surface temperature anomalies
2007
Abstract The Madden–Julian oscillation (MJO) is analyzed using the reanalysis zonal wind– and satellite outgoing longwave radiation–based indices of Wheeler and Hendon for the 1974–2005 period. The average lifetime of the MJO events varies with season (36 days for events whose central date occurs in December, and 48 days for events in September). The lifetime of the MJO in the equinoctial seasons (March–May and October–December) is also dependent on the state of El Niño–Southern Oscillation (ENSO). During October–December it is only 32 days under El Niño conditions, increasing to 48 days under La Niña conditions, with similar values in northern spring. This difference is due to faster eastw…
Effects of Red Cell Spacing and Red Cell Movement Upon Oxygen Release Under Conditions of Maximally Working Skeletal Muscle
1989
The impacts of the particulate nature of blood upon capillary O 2 release have been studied extensively by Federspiel and Sarelius [8] and by Federspiel and Popel [9]. The latter authors found that the O 2 flux out of a capillary decreases rapidly as intracapillary red blood cell spacing increases. The O 2 flux out of a single RBC, however, is enhanced as long as the inter-erythrocytic plasma gap does not exceed the “zone-of-influence” of a single RBC, which they determined to be about 1 capillary diameter. In their model, they considered spherical red cells contained in a cylindrical tube filled with plasma, on the lateral surface of which a boundary Po 2 was specified. Based on earlier st…
Magnetic field controlled FZ single crystal growth of intermetallic compounds
2005
Abstract Intermetallic rare-earth-transition-metal compounds with their coexistence of magnetic ordering and superconductivity are still of great scientific interest. The crystal growth of bulk single crystals is very often unsuccessful due to an unfavorable solid–liquid interface geometry enclosing concave fringes. The aim of the work is the contactless control of heat and material transport during floating-zone single crystal growth of intermetallic compounds. This control is provided by a tailored design of the electromagnetic field and the resulting electromagnetically driven convection. Numerical simulations for the determination of the electromagnetic field configuration induced by th…
Free-surface flows solved by means of SPH schemes with numerical diffusive terms
2010
A novel system of equations has been defined which contains diffusive terms in both the continuity and energy equations and, at the leading order, coincides with a standard weakly-compressible SPH scheme with artificial viscosity. A proper state equation is used to associate the internal energy variation to the pressure field and to increase the speed of sound when strong deformations/compressions of the fluid occur. The increase of the sound speed is associated to the shortening of the time integration step and, therefore, allows a larger accuracy during both breaking and impact events. Moreover, the diffusive terms allows reducing the high frequency numerical acoustic noise and smoothing …
Intramolecular proton transfer boosts water oxidation catalyzed by a Ru complex
2015
We introduce a new family of complexes with the general formula [Run(tda)(py)2]m+ (n = 2, m = 0, 1; n = 3, m = 1, 2+; n = 4, m = 2, 32+), with tda2– being [2,2′:6′,2″-terpyridine]-6,6″-dicarboxylate, including complex [RuIV(OH)(tda-κ-N3O)(py)2]+, 4H+, which we find to be an impressive water oxidation catalyst, formed by hydroxo coordination to 32+ under basic conditions. The complexes are synthesized, isolated, and thoroughly characterized by analytical, spectroscopic (UV–vis, nuclear magnetic resonance, electron paramagnetic resonance), computational, and electrochemical techniques (cyclic voltammetry, differential pulse voltammetry, coulometry), …