Search results for "VOLUME"

Can Soft Models Describe Polymer Knots?

2020

Similar to macroscopic ropes and cables, long polymers create knots. We address the fundamental question whether and under which conditions it is possible to describe these intriguing objects with crude models that capture only mesoscale polymer properties. We focus on melts of long polymers which we describe by a model typical for mesoscopic simulations. A worm-like chain model defines the polymer architecture. To describe nonbonded interactions, we deliberately choose a generic "soft" repulsive potential that leads to strongly overlapping monomers and coarse local liquid structure. The soft model is parametrized to accurately reproduce mesoscopic structure and conformations of reference p…

In Reply to the Letter to the Editor: “Comparing the Volume of Brain Metastases in F-18-FET-PET and MRI”

2016

Apport de la topographie par LiDAR aéroporté à la caractérisation volumique et spatiale d’amas de déchets sidérurgiques. L’exemple des ateliers de Mo…

2022

Parmi les grands districts de production de fer brut connus, la Puisaye (Bourgogne du nord – Yonne et Nièvre) figure parmi les plus importants à l’échelle métropolitaine, si ce n’est à l’échelle européenne. Plus de 2500 amas de déchets, marquant l’emplacement d’ateliers de réduction du minerai de fer, sont ainsi connus en prospections (Piétak et al. 2012). Les résultats des travaux engagés depuis 2017 dans le cadre d’un Projet Collectif de Recherche, financé par la DRAC Bourgogne-Franche-Comté et le CNRS, ont permis de révéler la continuité de ces activités de production du fer depuis le premier âge du fer jusqu’au second Moyen âge. Pour la période antique, ces amas de déchets se caractéris…

Optimizing the Sampling Area across an Old-Growth Forest via UAV-Borne Laser Scanning, GNSS, and Radial Surveying

2022

Aboveground biomass, volume, and basal area are among the most important structural attributes in forestry. Direct measurements are cost-intensive and time-consuming, especially for old-growth forests exhibiting a complex structure over a rugged topography. We defined a methodology to optimize the plot size and the (total) sampling area, allowing for structural attributes with a tolerable error to be estimated. The plot size was assessed by analyzing the semivariogram of a CHM model derived via UAV laser scanning, while the sampling area was based on the calculation of the absolute relative error as a function of allometric relationships. The allometric relationships allowed the structural …

The measurement of light transmission through an irradiated fluidised bed

1983

Abstract The transmission of light through an irradiated fluidised bed with vertical flat walls containing catalytic particles has been experimentally studied. The amount of light transmitted through the reactor was measured at different levels by a photocell. The experimental variables studied included: (i) gas flow rate, varying from 2 to more than 10 times that required for minimum fluidisation; (ii) mean particle size, ranging from 0.138 to 0.275 mm; and (iii) internal bed thickness from 2.1 to 4.9 mm. The effect of the reflectance of the particles was also examined. Results show that the amount of light transmitted through a flat fluidised bed is low. The average transmitted light has …

Some diffusion equations with finite propagation speed

2007

We summarize some of our recent results on diffusion equations with finite speed of propagation. These equations have been introduced to correct the infinite speed of propagation predicted by the classical linear diffusion theory. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Small-angle x-ray scattering experiments for investigating the validity of the two-phase model

1973

A New method for evaluating SAXS curves of polymer samples with lamellar structure is applied to two typical scattering curves measured with a solution-crystallized linear polyethylene and a melt-crystallized branched polyethylene respectively. The method permits a rigorous check of the validity of the two-phase model and yields, without additional measurement, the volume fractions of the two phases and the difference in their densities. The densities can than be obtained by measuring the overall density of the sample. The results are: ρc = 0.996 g/cm3,ρa = 0.854 g/cm3, wa = 0.20 for the solution-crystallized sample; ρc = 0.967 g/cm3,ρa = 0.850 g/cm3, wa = 0.36 for the melt-crystallized sam…

Gravitational flow of a thin film of liquid metal in a strong magnetic field

2014

Abstract The influence of a poloidal magnetic field of the spherical Tokamak on super thin (h ≈ 0.1 mm) film flow of liquid metal driven by gravity over the surface of the cooled divertor plate is addressed. The experimental setup developed at the Institute of Physics, University of Latvia (IPUL) is described, which makes it possible to drive and visualize such liquid metal flows in the solenoid of the superconducting magnet “Magdalena”. As applied to the above setup, the magnetic field effect on the operation of the capillary system of liquid metal flow distribution (CSFD) is evaluated by using molten metal (lithium or eutectic InGaSn alloy) with a very small linear flowrate q ≤ 1 mm2/s, s…

Hepatocellular Carcinoma Presenting at Contrast-Enhanced Multi–Detector-Row Computed Tomography or Gadolinium-Enhanced Magnetic Resonance Imaging as …

2012

OBJECTIVE: The objective of the study was to measure growth rate and to determine the optimal interval time for imaging follow-up of hepatocellular carcinomas (HCCs) presenting at multi-detector-row computed tomography (MDCT) or magnetic resonance imaging (MRI) as small, indeterminate lesions. METHODS: We included patients with cirrhosis with HCC initially presenting as indeterminate lesion of 2 cm or less at MDCT or MRI August 2005 to August 2009 and with available imaging follow-up. Measures of tumor growth included tumor volume doubling time (TVDT), tumor percentual diameter increase, and tumor percentual volume increase. RESULTS: We examined 48 patients (mean age, 64 years) with 69 HCCs…

Stationary–mobile phase distribution coefficient for polystyrene standards

2002

The measured shifts of the retention volume V R of polystyrene (PS) towards lower values in benzene–methanol (Bz–MeOH), and towards higher values in butanone–heptane (But–Hep) are in agreement with our theoretical model, in which both MeOH and But are adsorbed on Lichrospher. This paved way for us to model the chromatographic stationary (s)-phase as MeOH and the mobile (m)-phase as Bz–MeOH, and to calculate the distribution coefficients for PS. For But–Hep, the s-phase has been modeled as But, and the m-phase as But–Hep. A linear relation for the experimental equilibrium distribution P sm of PS is shown between the s- and m- phases in Bz–MeOH and But–Hep vs. the logarithm of the molecular m…