14,988 research outputs found
Physical limitations to the spatial resolution of solid-state detectors
In this paper we explore the effect of -ray emission, fluctuations in
th e signal deposition on the detection of charged particles in silicon-based
detec tors. We show that these two effects ultimately limit the resolution that
can be achieved by interpolation of the signal in finely segmented
position-sensitive solid-state devices.Comment: 5 page
Nonaffine rubber elasticity for stiff polymer networks
We present a theory for the elasticity of cross-linked stiff polymer
networks. Stiff polymers, unlike their flexible counterparts, are highly
anisotropic elastic objects. Similar to mechanical beams stiff polymers easily
deform in bending, while they are much stiffer with respect to tensile forces
(``stretching''). Unlike in previous approaches, where network elasticity is
derived from the stretching mode, our theory properly accounts for the soft
bending response. A self-consistent effective medium approach is used to
calculate the macroscopic elastic moduli starting from a microscopic
characterization of the deformation field in terms of ``floppy modes'' --
low-energy bending excitations that retain a high degree of non-affinity. The
length-scale characterizing the emergent non-affinity is given by the ``fiber
length'' , defined as the scale over which the polymers remain straight.
The calculated scaling properties for the shear modulus are in excellent
agreement with the results of recent simulations obtained in two-dimensional
model networks. Furthermore, our theory can be applied to rationalize bulk
rheological data in reconstituted actin networks.Comment: 12 pages, 10 figures, revised Section II
Renal handling of prednisolone/prednisone: effect of steroid dose and llβ-hydroxysteroid dehydrogenase
The purposes of this study were: (1) to determine under steady-state conditions whether the renal clearance of prednisolone is concentration dependent, and (2) to establish whether the urinary excretion of prednisolone and its biologically inactive 11-dehydro metabolite prednisone depend upon the activity of 11β-hydroxysteroid dehydrogenase (11β-OHSD). For that purpose 10 healthy volunteers were infused to steady state over a 13-h period either at a low (11 μg/h × kg) or a high (70 μg/h × kg) rate with prednisolone on two occasions, once without and once with administration of glycyrrhetinic acid, an inhibitor of 11β-OHSD. Prednisolone and prednisone were measured by high-pressure liquid chromatography. Mean renal clearance values of total or unbound prednisolone were several times higher during the high than the low infusion rate. The fractional renal clearance of unbound prednisolone during the high, but not during the low infusion rate exceeded 1. This indicates that in addition to unbound prednisolone, protein-bound prednisolone is excreted in urine at high plasma concentrations. Inhibition of 11β-OHSD increased the urinary ratios of prednisolone/prednisone in all subjects. Conclusions: (1) The renal clearance of prednisolone is concentration dependent; (2) there must be tubular secretion and/or glomerular filtration of prednisolone bound to plasma proteins; (3) the urinary excretion of prednisolone/prednisone is modulated by the activity of 11 β-OHS
Consumer’s circular behaviors in relation to the purchase, extension of life, and end of life management of electrical and electronic products: A review
Nowadays, management of electrical and electronic equipment (EEE) and the related waste electrical and electronic equipment (WEEE) is a growing concern around the world and clearly an open issue to tackle in order to move towards a more circular economy. The goal of this review paper is to analyze and summarize research conducted exploring behaviors connected with purchases, extension of useful life, and management of end of life of electrical and electronic equipment. The results highlight several research exploring the determinants of WEEE recycling behavior, also in relation with different practices (e.g., online recycling); on the other hand other typologies of behaviors are less analyzed in the literature (e.g., purchase of used EEE products, donation of EEE products, participation in WEEE takeback activities established by firm operating in this sector, etc.). Moreover, the results suggest that the theoretical model adopted in many studies reveals its usefulness to predict the determinist of such circular consumer’s behavior in relation to the purchase, extension of life, and end of life management of electrical and electronic products; however, in many cases, additional variables are needed to fully explain the behavior
Automated longitudinal control based on nonlinear recursive B-spline approximation for battery electric vehicles
This works presents a driver assistance system for energy-efficient ALC of a BEV. The ALC calculates a temporal velocity trajectory from map data. The trajectory is represented by a cubic B-spline function and results from an optimization problem with respect to travel time, driving comfort and energy consumption. For the energetic optimization we propose an adaptive model of the required electrical traction power. The simple power train of a BEV allows the formulation of constraints as soft constraints. This leads to an unconstrained optimization problem that can be solved with iterative filter-based data approximation algorithms. The result is a direct trajectory optimization method of which the effort grows linearly with the trajectory length, as opposed to exponentially as with most other direct methods. We evaluate ALC in real test drives with a BEV. We also investigate the energy-saving potential in driving simulations with ALC compared to MLC. On the chosen reference route the ALC saves up to 3.4% energy compared to MLC at same average velocity, and achieves a 2.6% higher average velocity than MLC at the same energy consumptio
Scaling function for the noisy Burgers equation in the soliton approximation
We derive the scaling function for the one dimensional noisy Burgers equation
in the two-soliton approximation within the weak noise canonical phase space
approach. The result is in agreement with an earlier heuristic expression and
exhibits the correct scaling properties. The calculation presents the first
step in a many body treatment of the correlations in the Burgers equation.Comment: Replacement: Several corrections, 4 pages, Revtex file, 3 figures. To
appear in Europhysics Letter
The compact radio structure of the high-redshift blazar J1430+4204 before and after a major outburst
The high-redshift (z=4.72) blazar J1430+4204 produced an exceptional radio
outburst in 2006. We analyzed 15-GHz radio interferometric images obtained with
the Very Long Baseline Array (VLBA) before and after the outburst, to search
for possible structural changes on milli-arcsecond angular scales and to
determine physical parameters of the source.Comment: Proceedings of the 5th Workshop of Young Researchers in Astronomy and
Astrophysics, Budapest, 2009; to be published in J. Phys.: Conf. Series
(JPCS); 4 pages, 3 figure
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