El mercado central de Santiago: Antes de su embarque a Chile

La fantasía de la globalización ronda Chile desde la Colonia. El edificio del Mercado Central de Santiago, cuya estructura fue diseñada y construida en Gran Bretaña, hoy es objeto de miradas anestesiadas; sin embargo, en la época de su construcción fue considerado en Europa como caso ejemplar de la arquitectura metálica de ultramar

Advances in imaging THGEM-based detectors

The thick GEM (THGEM) [1] is an "expanded" GEM, economically produced in the PCB industry by simple drilling and etching in G-10 or other insulating materials (fig. 1). Similar to GEM, its operation is based on electron gas avalanche multiplication in sub-mm holes, resulting in very high gain and fast signals. Due to its large hole size, the THGEM is particularly efficient in transporting the electrons into and from the holes, leading to efficient single-electron detection and effective cascaded operation. The THGEM provides true pixilated radiation localization, ns signals, high gain and high rate capability. For a comprehensive summary of the THGEM properties, the reader is referred to [2, 3]. In this article we present a summary of our recent study on THGEM-based imaging, carried out with a 10x10 cm^2 double-THGEM detector.Comment: 3 pages, 3 figures. Presented at the 10th Pisa Meeting on Advanced Detectors; ELBA-Italy; May 21-27 200

Spectra of ultrabroadband squeezed pulses and the finite-time Unruh-Davies effect

We study spectral properties of quantum radiation of ultimately short duration. In particular, we introduce a continuous multimode squeezing operator for the description of subcycle pulses of entangled photons generated by a coherent-field driving in a thin nonlinear crystal with second order susceptibility. We find the ultrabroadband spectra of the emitted quantum radiation perturbatively in the strength of the driving field. These spectra can be related to the spectra expected in an Unruh-Davies experiment with a finite time of acceleration. In the time domain, we describe the corresponding behavior of the normally ordered electric field variance.Comment: 11 pages, 5 figure

On the space of generalized fluxes for loop quantum gravity

We show that the space of generalized fluxes - momentum space - for loop quantum gravity cannot be constructed by Fourier transforming the projective limit construction of the space of generalized connections - position space - due to the non-abelianess of the gauge group SU(2). From the abelianization of SU(2), U(1)^3, we learn that the space of generalized fluxes turns out to be an inductive limit, and we determine the consistency conditions the fluxes should satisfy under coarse-graining of the underlying graphs. We comment on the applications to loop quantum cosmology, in particular, how the characterization of the Bohr compactification of the real line as a projective limit opens the way for a similar analysis for LQC

The psychometric properties of the Portuguese version of the Personality Inventory for DSM-5

The DSM-5 Section III proposes a hybrid dimensional-categorical model of conceptualizing personality and its disorders that includes assessment of impairments in personality functioning (criterion A) and maladaptive personality traits (criterion B). The Personality Inventory for the DSM-5 is a new dimensional tool, composed of 220 items organized into 25 facets that delineate ?ve higher order domains of clinically relevant personality differences, and was developed to operationalize the DSM-5 model of pathological personality traits. The current studies address the internal consistency (study 1), the test-retest reliability (study 2) and the criterion validity (studies 3 and 4) of the Portuguese version of the PID-5 in samples of native speaking psychology students. Results indicated good internal consistency reliabilities and good temporal stability reliabilities for the majority of the PID-5 traits. The correlational pattern of the PID-5 traits with two measures of personality was in accordance with theoretical expectations and showed its concurrent validity.info:eu-repo/semantics/acceptedVersio

Experiment and modelling of the strain-rate-dependent response during in vitro degradation of PLA fibres

Polylactic acid (PLA) fibres present, in their pristine state, a strain-rate-dependent behaviour. Their mechanical properties evolve during in vitro biodegradation. Tensile tests of PLA fibres are performed at five different strain rates 0.0001, 0.001, 0.01, 0.05 and 0.1/s and at seven degradation stages, 0, 20, 40, 60, 90, 120 and 150 days in a phosphate buffer solution at constant temperature at 37 degrees C. The mechanical response is modelled using a modified three-element standard solid model proposed for polymers under finite deformations range. Observations on experimental data lead to the conclusion that the viscous parameters eta(1) and eta(2) are strain rate dependent, and they vary from 10,762/3202 (N/m s) at the lowest strain rate of 0.0001/s, and 12.2/9.1 (N/m s) at the highest strain rate of 0.1/s for eta(1) and eta(2), respectively, thus, depicting the shear-thinning phenomena with the increase in strain rate. Whereas stiffness parameters C-1 and C-2 are degradation dependent, they vary from 21.6/13.7 (N/m) for undegraded PLA fibres and 9.7/5.4 (N/m) for 150 days degraded PLA fibres for C-1 and C-2, respectively. Decay of stiffness parameters during biodegradation follows an exponential law. The model will be useful to design and develop new fibrous structures for ligament augmentation devices. It could contribute to develop better devices with improved mechanical performance helping those patients in need to repair the ligament tissue

Influence of 3D microstructure for improving the thermal performance of building façades

The thermal performance of a building is highly dependent on the heat transmission through the envelope. On the other hand, additive manufacturing has been increasingly used in several industrial applications due to its possibility to produce complex structures. However, most studies of the 3d printing process focused on mechanical performance. This study aims to evaluate how the internal 3D-printed microstructure affects thermal performance. Twelve infill patterns were analysed, including Gyroid, Grid, Hilbert curve, Line, Rectilinear, Stars Triangles, 3D Honeycomb, Honeycomb, Concentric, Cubic, and Octagram spiral. Using fused deposition modelling (FDM), the samples were printed with polyethene terephthalate-glycol (PET-G) thermoplastic filaments. Thermal tests were conducted using a calibrated hotbox, following the recommendations of ASTM C1363-11:2014. The results obtained show a variation of 70% by changing the internal microstructure using fix infill density of 25%. Concentric, Gyroid and Hilbert curve achieved the best thermal insulation properties.The authors would like to acknowledge the financial support granted by NORTE-45-2020-75. The contribution of the work of Paulo Renato Quintas during the analysis and development of the analysed specimens, and the technical support of Prof. Ricardo Mateus, Adilson Junior and Lívia Cosentino during the hotbox experiments

Performance evaluation of a compression algorithm for wireless sensor networks in monitoring applications

Wireless sensor network (WSN) is an emerging technology that targets multiple applications in the different environments. Its infrastructure is composed of a large number of sensor nodes with a limited physical capacity and low cost. The energy consumption must be as optimized as possible in order to extend its lifetime. The use of data compression techniques can be an advantage in the WSN context, once these techniques eliminate transmission of redundant information and consequently can be adopted to minimize the consumption of energy in the sensor nodes. WSN for monitoring applications can benefit from this technique as it may maximize the lifetime of batteries. The main motivation of this paper is to investigate the performance of a data compression algorithm for WSN in the context of monitoring applications. To validate the proposal, simulation experiments have been performed using the Network Simulator (NS-2) tool

Modeling extreme wave heights from laboratory experiments with the nonlinear Schrödinger equation

Spatial variation of nonlinear wave groups with different initial envelope shapes is theoretically studied first, confirming that the simplest nonlinear theoretical model is capable of describing the evolution of propagating wave packets in deep water. Moreover, three groups of laboratory experiments run in the wave basin of CEHIPAR (Canal de Experiencias Hidrodinámicas de El Pardo, known also as El Pardo Model Basin) was founded in 1928 by the Spanish Navy. are systematically compared with the numerical simulations of the nonlinear Schrödinger equation. Although a little overestimation is detected, especially in the set of experiments characterized by higher initial wave steepness, the numerical simulation still displays a high degree of agreement with the laboratory experiments. Therefore, the nonlinear Schrödinger equation catches the essential characteristics of the extreme waves and provides an important physical insight into their generation. The modulation instability, resulting from the quasi-resonant four-wave interaction in a unidirectional sea state, can be indicated by the coefficient of kurtosis, which shows an appreciable correlation with the extreme wave height and hence is used in the modified Edgeworth–Rayleigh distribution. Finally, some statistical properties on the maximum wave heights in different sea states have been related with the initial Benjamin–Feir index