Search results for "shadow"
showing 10 items of 119 documents
Neoclassical Growth, Environment and Technological Change: The Environmental Kuznets Curve
2009
The paper investigates socially optimal patterns of economic growth and environmental quality in a neoclassical growth model with endogenous technological progress. In the model, the environmental quality affects positively not only to utility but also to production. However, cleaner technologies can be used in the economy whether a part of the output is used in environmentally oriented R&D. In this framework, if the initial level of capital is low then the shadow price of a cleaner technology is low relative to the cost of developing it given by the marginal utility of consumption and it is not worth investing in R&D. Thus, there will be a first stage of growth based only on the accumulati…
On vortex shape in unbaffled stirred vessels as measured by digital image analysis
2012
In this work, digital image analysis coupled with a suitable shadowgraphy-based technique is employed to investigate the shape of the free-surface vortex that forms in uncovered unbaffled tanks stirred by either a D=T/3 Lightnin A310 or a D=T/3 Rushton turbine. The technique is based on back-lighting the vessel and suitably averaging vortex images over time. Data obtained show that the two different impellers give rise to quite different vortex shapes. A novel 2-parameter model is proposed that successfully describes vortex shapes obtained with both impellers.
Complete Shadowing Modeling and its Effect on System Level Performance Evaluation
2008
Computer simulations are a common procedure for assessing the performance of new algorithms. To conduct a valid and accurate study, the models employed in such simulators need to be carefully selected. Regarding shadowing modeling, one-dimensional models are fairly commonplace in the literature. While simple and with low computational costs, these models can not produce correlated fading values for mobiles that are in nearby positions and, besides, do not include the cross-correlation effect. To overcome these limitations, this paper presents a bi-dimensional shadowing model which introduces both the spatial correlation and the cross-correlation present in real systems. Finally, the impact …
Strassmann in the shadow
1996
Spatial Reconstruction Algorithm of DT Layer in Cryogenic Targets Using Optical Techniques
2007
The measurements of the solid DT layer, in terms of thickness and roughness, in the LMJ geometry (i.e. in a hohlraum) are not trivial. The DT layer measurements will be done using a Matsukov-Cassegrain telescope placed 39 cm away from the target. This telescope will be used to acquire shadowgraphy images on equators, and interferometric measurements on pole areas using optical coherence tomography (OCT). Optical coherence tomography allows determining the DT layer thickness on a few points, in the polar regions of the target. By scanning around the poles, several points can be acquired in order to calculate the roughness and the local shape of the DT layer at the pole. Both techniques were …
A Model to Characterize the D-T Layer of ICF Targets by Backlit Optical Shadowgraphy
2005
A numerical model is presented in order to modelize the bright ring that appears in backlit optical shadowgraphy on a transparent hollow sphere with a solid deuterium-tritium layer inside. This novel model is based on computational calculations applied to the problem of the targets used in inertial confinement fusion. The model takes into account the influences of the optical imaging system (numerical aperture, source divergence, camera resolution, etc.) and the effect of the capsule itself, diameter, thickness, and refractive index, and allows one to analyze the inner surface of a capsule in terms of thickness and roughness.
Influence of beam conditions and energy for SEE testing
2012
GANIL/Applications industrielles; The effects of heavy-ion test conditions and beam energy on device response are investigated. These effects are illustrated with two types of test vehicles: SRAMs and power MOSFETs. In addition, GEANT4 simulations have also been performed to better understand the results. Testing to high fluence levels is required to detect rare events. This increases the probability of nuclear interactions. This is typically the case for power MOSFETs, which are tested at high fluences for single event burnout or gate rupture detection, and for single-event-upset (SEU) measurement in SRAMs below the direct ionization threshold. Differences between various test conditions (…
Photoproduction of light vector mesons in Xe–Xe ultraperipheral collisions at the LHC and the nuclear density of Xe-129
2018
We make predictions for cross sections of $\rho$ and $\phi$ vector meson photoproduction in ultraperipheral Xe-Xe collisions at $\sqrt{s_{NN}}=5.44$ TeV. Analyzing the momentum transfer distribution of $\rho$ mesons in this process, we explore the feasibility of extracting the nuclear density of $^{129}$Xe, which is needed in searches for dark matter with Xenon-based detectors.
Observation of the cosmic-ray shadow of the Moon with IceCube
2013
We report on the observation of a significant deficit of cosmic rays from the direction of the Moon with the IceCube detector. The study of this "Moon shadow" is used to characterize the angular resolution and absolute pointing capabilities of the detector. The detection is based on data taken in two periods before the completion of the detector: between April 2008 and May 2009, when IceCube operated in a partial configuration with 40 detector strings deployed in the South Pole ice, and between May 2009 and May 2010 when the detector operated with 59 strings. Using two independent analysis methods, the Moon shadow has been observed to high significance (> 6 sigma) in both detector config…
Nuclear Shadowing in a Parton Recombination Model
1993
Deep inelastic structure functions $F_2^A(x)$ are investigated in a $Q^2$ rescaling model with parton recombination effects. We find that the model can explain experimentally measured $F_2^A(x)$ structure functions reasonably well in the wide Bjorken$-x$ range ($0.005<x<0.8$). In the very small $x$ region ($x<0.02$), recombination results are very sensitive to input sea-quark and gluon distributions.