The effect of a nucleating agent on lamellar growth in melt-crystallizing polyethylene oxide

The effects of a (non co-crystallizing) nucleating agent on secondary nucleation rate and final lamellar thickness in isothermally melt-crystallizing polyethylene oxide are considered. SAXS reveals that lamellae formed in nucleated samples are thinner than in the pure samples crystallized at the same undercoolings. These results are in quantitative agreement with growth rate data obtained by calorimetry, and are interpreted as the effect of a local decrease of the basal surface tension, determined mainly by the nucleant molecules diffused out of the regions being about to crystallize. Quantitative agreement with a simple lattice model allows for some interpretation of the mechanism.Comment: submitted to Journal of Applied Physics (first version on 22 Apr 2002

Rotational sensitivity of the "G-Pisa" gyrolaser

G-Pisa is an experiment investigating the possibility to operate a high sensitivity laser gyroscope with area less than $1 \rm m^2$ for improving the performances of the mirrors suspensions of the gravitational wave antenna Virgo. The experimental set-up consists in a He-Ne ring laser with a 4 mirrors square cavity. The laser is pumped by an RF discharge where the RF oscillator includes the laser plasma in order to reach a better stability. The contrast of the Sagnac fringes is typically above 50% and a stable regime has been reached with the laser operating both single mode or multimode. The effect of hydrogen contamination on the laser was also checked. A low-frequency sensitivity, below $1 \rm Hz$, in the range of $10^{-8} \rm {(rad / s)/ \sqrt{Hz}}$ has been measured.Comment: 6 pages, 6 figures, presented at the EFTF-IFCS joint conference 200

Carbon nanotubes as target for directional detection of light WIMP

In this paper I will briefly introduce the idea of using Carbon Nanotubes (CNT) as target for the detection of low mass WIMPs with the additional information of directionality. I will also present the experimental efforts of developing a Time Projection Chamber with a CNT target inside and the results of a test beam at the Beam Test Facility of INFN-LNF.Comment: 3 figures, IFAE2017 poster session proceeding

Spot size measurements in the Eli-NP compton gamma source

A high brightness electron Linac is being built in the Compton Gamma Source at the ELI Nuclear Physics facility in Romania. To achieve the design luminosity, a train of 32 bunches with a nominal charge of 250 pC and 16 ns spacing , will collide with the laser beam in the interaction point. Electron beam spot size is measured with an OTR (optical transition radiation) profile moni-tors. In order to measure the beam properties, the optical radiation detecting system must have the necessary accu-racy and resolution. This paper deals with the studies of different optic configurations to achieve the magnifica-tion, resolution and accuracy desired considering design and technological constraints; we will compare several configurations of the optical detection line to justify the one chosen for the implementation in the Lina

Some observations on the relationship of manifest and hidden esca to rainfall

This paper reports observations on the relationship between the yearly incidence of manifest esca (i.e. diseased plants which show foliar symptoms), hidden esca (that which remains asymptomatic throughout a growing season) and rainfall. Data from three vineyards (two in Tuscany and one in Emilia-Romagna, Italy) showed that rainfall in May-July or only in July was inversely related with hidden esca. For two vineyards, TB in Emilia-Romagna and CAR-3 in Tuscany, the spatial pattern of diseased vines in the first year of appearance of the foliar esca symp-toms was also determined. The maps of the vines in these vineyards indicated that diseased plants mostly occurred alone. This suggests that the disease had its origin in infected rooted cuttings or was triggered by inoculum aerially dispersed from distant sources and/or occurring, at least in hypothesis, in the soil

Intense terahertz pulses from SPARC-LAB coherent radiation source

The linac-based Terahertz source at the SPARC_LAB test facility is able to gene rate highly intense Terahertz broadband pulses via coherent transition radiation (CTR) from high brightness electron beams. The THz pulse duration is typically down to 100 fs RMS and can be tuned through the electron bunch duration and shaping. The measured stored energy in a single THz pulse has reached 40 μ J, which corresponds to a peak electric field of 1.6 MV/cm at the THz focus. Here we present the main features, in particular spatial and sp ectral distributions and energy characterizations of the SPARC_LAB THz source, which is very competitive for investigations in Condensed Matter, as well as a valid tool for electron beam longitudinal diagnostics

Experimental Test of Two-way Quantum Key Distribution in Presence of Controlled Noise

We describe the experimental test of a quantum key distribution performed with a two-way protocol without using entanglement. An individual incoherent eavesdropping is simulated and induces a variable amount of noise on the communication channel. This allows a direct verification of the agreement between theory and practice.Comment: 4 pages, 3 figure

A comparison between methods of analytical continuation for bosonic functions

In this article we perform a critical assessment of different known methods for the analytical continuation of bosonic functions, namely the maximum entropy method, the non-negative least-square method, the non-negative Tikhonov method, the Pad\'e approximant method, and a stochastic sampling method. Three functions of different shape are investigated, corresponding to three physically relevant scenarios. They include a simple two-pole model function and two flavours of the non-interacting Hubbard model on a square lattice, i.e. a single-orbital metallic system and a two-orbitals insulating system. The effect of numerical noise in the input data on the analytical continuation is discussed in detail. Overall, the stochastic method by Mishchenko et al. [Phys. Rev. B \textbf{62}, 6317 (2000)] is shown to be the most reliable tool for input data whose numerical precision is not known. For high precision input data, this approach is slightly outperformed by the Pad\'e approximant method, which combines a good resolution power with a good numerical stability. Although none of the methods retrieves all features in the spectra in the presence of noise, our analysis provides a useful guideline for obtaining reliable information of the spectral function in cases of practical interest.Comment: 13 pages, 9 figure

Online Superstructure Optimization for Energy Saving of an Industrial Gas Distribution System

Mixed-integer optimization is a common approach to handle decision-making problems. Nevertheless, such an approach still presents certain operational limitations, especially for online superstructures. One of these limitations is given by Jacobian singularity, which arises for certain combinations of the set of Boolean variables and which easily leads to possible infeasible numerical solutions. This paper proposes a novel approach to overcome this problem, ensuring the use of mixed-integer optimization also to solve online issues. The case of nitrogen supply for the Thyssen-Krupp steel mill placed in Terni (Italy) is considered as validation case