Search results for "maximum"

2003

A thermodynamic approach to nonlocal plasticity and related variational principles

1999

Elastic-plastic rate-independent materials with isotropic hardening/softening of nonlocal nature are considered in the context of small displacements and strains. A suitable thermodynamic framework is envisaged as a basis of a nonlocal associative plasticity theory in which the plastic yielding laws comply with a (nonlocal) maximum intrinsic dissipation theorem. Additionally, the rate response problem for a (continuous) set of (macroscopic) material particles, subjected to a given total strain rate field, is discussed and shown to be characterized by a minimum principle in terms of plastic coefficient. This coefficient and the relevant continuum tangent stiffness matrix are shown to admit, …

Optimal Control of Dissipative Quantum Systems

2008

We study the control of finite dimensional quantum systems by external laser fields. After examining the concrete example of the diatomic molecular alignment in dissipative media, we are interested in the problem of optimal control, where the objective is to bring the system from an initial state into a given final state while minimizing a cost functional. The Pontryagin maximum principle (PMP) provides necessary conditions for optimality, by establishing that any optimal trajectory is the extremal solution of an extended problem of Hamiltonian structure. In this context, we perform the analysis of two particular systems. The first one is a dissipative 2-level system, for which we determine…

CT-Angiographie bei arterieller Verschlußkrankheit: Vergleich von 3 Rekonstruktionsverfahren

1997

Purpose To evaluate different rendering techniques of CT data for the assessment of long vessel segments in peripheral vascular occlusive disease. Material and methods 40 CT angiograms (aortoiliac: n = 20, leg arteries: n = 20) were viewed using three different rendering techniques: 1, maximum intensity projection (MIP); 2, volume rendering (VR); 3, shaded surface display (SSD). CT angiograms were obtained in 6 or 8 projections. Axial cross-section images were analysed using an interactive cine mode. Intraarterial DSA was the standard in all cases. Results The sensitivities for the diagnosis of occlusive disease were 100% (cross-section images), 94% (MIP), 91% (VR) and 93% (SSD). The specif…

Influence of fat mass for the VO2max and ventilatory thresholds in young athletes of endurance sport specialties

2016

[Resumen] El objetivo del estudio es analizar la influencia de la masa grasa total y su % respecto al peso corporal total, así como la masa grasa regionalizada (Σ pliegues tronco, Σ pliegues abdomen, cociente TS/TI, phantom (Ph) de los pliegues) y su % respecto a la masa grasa total, en relación al VO2max y los Umbrales Ventilatorios (VT1 y VT2) en jóvenes deportistas en función de su especialidad deportiva y grupo de edad. La muestra está compuesta por 400 deportistas de ambos sexos del Centro de Tecnificación de Cheste (Valencia) clasificados en 3 grupos de edad: 0,05) entre atletismo y natación. Para el caso de los grupos de edad se han encontrado diferencias significativas (p0,05) entre…

Precision measurement of the mass of the tau lepton

2014

An energy scan near the $\tau$ pair production threshold has been performed using the BESIII detector. About $24$ pb$^{-1}$ of data, distributed over four scan points, was collected. This analysis is based on $\tau$ pair decays to $ee$, $e\mu$, $eh$, $\mu\mu$, $\mu h$, $hh$, $e\rho$, $\mu\rho$ and $\pi\rho$ final states, where $h$ denotes a charged $\pi$ or $K$. The mass of the $\tau$ lepton is measured from a maximum likelihood fit to the $\tau$ pair production cross section data to be $m_{\tau} = (1776.91\pm0.12 ^{+0.10}_{-0.13}$) MeV/$c^2$, which is currently the most precise value in a single measurement.

Infrared thermography assisted control for apples microwave drying

2012

A microwave based system was developed for drying of apple slices while on-line controlling their temperatures. An infrared thermography assisted control system allowed to realize temperature control by detecting the instantaneous maximum temperature among the samples under test instead of a chosen slice. The effectiveness of the system at hand in realizing temperature control both in space and in time was proven for three temperatures: 55, 65 and 75 C. Temperature fluctuations became larger both with time increasing and with rising temperature levels thus causing a negative impact on dried fruit quality. In fact apples slices dried at 75 C by microwave showed L⁄ (lightness) and white index…

Risk and resilience in the late glacial: A case study from the western Mediterranean

2018

Abstract The period spanning the Last Glacial Maximum through early Holocene encompasses dramatic and rapid environmental changes that offered both increased risk and new opportunities to human populations of the Mediterranean zone. The regional effects of global climate change varied spatially with latitude, topography, and distance from a shifting coastline; and human adaptations to these changes played out at these regional scales. To better understand the spatial and temporal dynamics of climate change and human social-ecological-technological systems (or SETS) during the transition from full glacial to interglacial, we carried out a meta-analysis of archaeological and paleoenvironmenta…

A large proportional drift chamber with two-dimensional read-out

1976

Abstract The construction and performance of a large drift chamber are described, which has a sensitive area of 5 m2 and an average chamber thickness of 0.55 × 10−3 radiation lengths. Simultaneous sense wire- and high voltage read-out gives a good time correlation with ajitter of 2.0 ns fwhm. Measurements with a collimated radioactive α-sources resulted in a time resolution of 4.3 ns fwhm corresponding to a space resolution of 0.20 mm fwhm at the sense wire. The space resolution at the high voltage plane is about 25 mm fwhm.

An algorithm for earthquakes clustering based on maximum likelihood

2007

In this paper we propose a clustering technique set up to separate and find out the two main components of seismicity: the background seismicity and the triggered one. We suppose that a seismic catalogue is the realization of a non homogeneous space-time Poisson clustered process, with a different parametrization for the intensity function of the Poisson-type component and of the clustered (triggered) component. The method here proposed assigns each earthquake to the cluster of earthquakes, or to the set of independent events, according to the increment to the likelihood function, computed using the conditional intensity function estimated by maximum likelihood methods and iteratively chang…