116 research outputs found
Reconstructing the thermal Green functions at real times from those at imaginary times
By exploiting the analyticity and boundary value properties of the thermal
Green functions that result from the KMS condition in both time and energy
complex variables, we treat the general (non-perturbative) problem of
recovering the thermal functions at real times from the corresponding functions
at imaginary times, introduced as primary objects in the Matsubara formalism.
The key property on which we rely is the fact that the Fourier transforms of
the retarded and advanced functions in the energy variable have to be the
`unique Carlsonian analytic interpolations' of the Fourier coefficients of the
imaginary-time correlator, the latter being taken at the discrete Matsubara
imaginary energies, respectively in the upper and lower half-planes. Starting
from the Fourier coefficients regarded as `data set', we then develop a method
based on the Pollaczek polynomials for constructing explicitly their analytic
interpolations.Comment: 23 pages, 2 figure
The European GreenBuilding: Projects Catalogue: September 2012– December 2013
This document describes some of the projects implemented by GreenBuilding Partners in the period September 2012 to December 2013. The projects have been implemented in different types of buildings, such as office buildings, schools, hotels, shopping mall, etc. Both new construction and the refurbishment of existing buildings are covered by the report.JRC.F.7-Renewables and Energy Efficienc
The European GreenBuilding Projects Catalogue 2014
In 2005 the European Commission launched the GreenBuilding Programme (GBP). GreenBuilding is a voluntary programme aiming at improving the energy efficiency of non-residential buildings in Europe on voluntary basis. The programme addresses owners of non-residential buildings to realise cost-effective measures which enhance the energy efficiency of their buildings in one or more technical services. The programme covers both existing and new buildings. The GreenBuilding Programme reached its 8th year of activity and has now achieved its original target of collecting data from over 1000 buildings. The Joint Research Centre (JRC) has therefore decided to close down the GreenBuilding Programme by 1st of October 2014.JRC.F.7-Renewables and Energy Efficienc
Instrumented indentation of transforming and no-transforming phases in Cu-Al-Be shape-memory alloys
The behavior of Cu-Al-Be alloys under instrumented indentation using a Berkovich tip was studied. The pseudoelastic effect was evidenced in the transforming β Cu-Al-Be phase as a closed hysteresis loop between the unloading-reloading paths in the P-h curves and high depth recovery ratios. From series of indentations conducted in the (β + γ 2) specimens, it was found that the indentation response of the two phases is remarkably different. Unlike the pseudoelastic β phase, γ 2 precipitates present an elastic-plastic behavior, obtaining a complete coincidence between the unload and reload path in the load-displacement curves, and a lower recovery capacity. An average contact pressure versus the penetration depth curve was estimated for each indentation curve, and results suggest that 8 GPa and 3 GPa can be considered an elastic limit for γ 2 and β phase respectively under Berkovich indenter stress state. The elastic modulus and the hardness of both phases were estimated from load-displacement curves using the Oliver and Pharr method.Fil: Montecinos Espinoza, Susana de Los Angeles. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ciencias Exactas. Instituto de Física de Materiales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil; ArgentinaFil: Cuniberti, Adela Maria. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ciencias Exactas. Instituto de Física de Materiales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil; ArgentinaFil: Simison, Silvia Noemi. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; Argentin
Localization of Electronic States in Chain Model Based on Real DNA Sequence
We investigate the localization property of an electron in the disordered
two-chain system (ladder model) with long-range correlation as a simple model
for electronic property in DNA sequence. The chains are constructed by
repetition of the sugar-phosphate sites, and the inter-chain hopping at the
sugar sites come from nucleotide pairs, i.e., or pairs. It has been
found that some DNA sequences have long-range correlation. In this paper we use
some actual DNA sequences such as bacteriophages of escherichia coli, human
omosome 22 and histone protein as the correlated sequence for the interchain
hopping at the sugar sites. We will present some numerical results for the
Lyapunov exponent (inverse localization length) of the wave function in the
cases in comparison to the results for artificial sequence generated by an
asymmetric modified Bernoulli map. It is shown that the correlation and
asymmetry of the sequence affect on the localization in both the artificial and
real DNA sequences.Comment: 12 pages, 4 figure
Monitoring microbial metabolites using an inductively coupled resonance circuit
We present a new approach to monitor microbial population dynamics in emulsion droplets via changes in metabolite composition, using an inductively coupled LC resonance circuit. The signal measured by such resonance detector provides information on the magnetic field interaction with the bacterial culture, which is complementary to the information accessible by other detection means, based on electric field interaction, i.e. capacitive or resistive, as well as optical techniques. Several charge-related factors, including pH and ammonia concentrations, were identified as possible contributors to the characteristic of resonance detector profile. The setup enables probing the ionic byproducts of microbial metabolic activity at later stages of cell growth, where conventional optical detection methods have no discriminating power
Photo--assisted current and shot noise in the fractional quantum Hall effect
The effect of an AC perturbation on the shot noise of a fractional quantum
Hall fluid is studied both in the weak and the strong backscattering regimes.
It is known that the zero-frequency current is linear in the bias voltage,
while the noise derivative exhibits steps as a function of bias. In contrast,
at Laughlin fractions, the backscattering current and the backscattering noise
both exhibit evenly spaced singularities, which are reminiscent of the
tunneling density of states singularities for quasiparticles. The spacing is
determined by the quasiparticle charge and the ratio of the DC bias
with respect to the drive frequency. Photo--assisted transport can thus be
considered as a probe for effective charges at such filling factors, and could
be used in the study of more complicated fractions of the Hall effect. A
non-perturbative method for studying photo--assisted transport at is
developed, using a refermionization procedure.Comment: 14 pages, 6 figure
Electronic localization at mesoscopic length scales: different definitions of localization and contact effects in a heuristic DNA model
In this work we investigate the electronic transport along model DNA
molecules using an effective tight-binding approach that includes the backbone
on site energies. The localization length and participation number are examined
as a function of system size, energy dependence, and the contact coupling
between the leads and the DNA molecule. On one hand, the transition from an
diffusive regime to a localized regime for short systems is identified,
suggesting the necessity of a further length scale revealing the system borders
sensibility. On the other hand, we show that the lenght localization and
participation number, do not depended of system size and contact coupling in
the thermodynamic limit. Finally we discuss possible length dependent origins
for the large discrepancies among experimental results for the electronic
transport in DNA sample
VADER: a variable dose-rate external 137Cs irradiator for internal emitter and low dose rate studies.
In the long term, 137Cs is probably the most biologically important agent released in many accidental (or malicious) radiation disasters. It can enter the food chain, and be consumed, or, if present in the environment (e.g. from fallout), can provide external irradiation over prolonged times. In either case, due to the high penetration of the energetic γ rays emitted by 137Cs, the individual will be exposed to a low dose rate, uniform, whole body, irradiation. The VADER (VAriable Dose-rate External 137Cs irradiatoR) allows modeling these exposures, bypassing many of the problems inherent in internal emitter studies. Making use of discarded 137Cs brachytherapy seeds, the VADER can provide varying low dose rate irradiations at dose rates of 0.1 to 1.2 Gy/day. The VADER includes a mouse "hotel", designed to allow long term simultaneous residency of up to 15 mice. Two source platters containing ~ 250 mCi each of 137Cs brachytherapy seeds are mounted above and below the "hotel" and can be moved under computer control to provide constant low dose rate or a varying dose rate mimicking 137Cs biokinetics in mouse or man. We present the VADER design and characterization of its performance over 18 months of use
- …