A robust comparison of dynamical scenarios in a glass-forming liquid

We use Bayesian inference methods to provide fresh insights into the sub-nanosecond dynamics of glycerol, a prototypical glass-forming liquid. To this end, quasielastic neutron scattering data as a function of temperature have been analyzed using a minimal set of underlying physical assumptions. On the basis of this analysis, we establish the unambiguous presence of three distinct dynamical processes in glycerol, namely, translational diffusion of the molecular centre of mass and two additional localized and temperature-independent modes. The neutron data also provide access to the characteristic length scales associated with these motions in a model-independent manner, from which we conclude that the faster (slower) localized motions probe longer (shorter) length scales. Careful Bayesian analysis of the entire scattering law favors a heterogeneous scenario for the microscopic dynamics of glycerol, where molecules undergo either the faster and longer or the slower and shorter localized motions.Peer ReviewedPostprint (author's final draft

Implanted muon spin spectroscopy on 2-O-adamantane: a model system that mimics the liquid

The transition taking place between two metastable phases in 2-O-adamantane, namely the [Formula: see text] cubic, rotator phase and the lower temperature P21/c, Z  =  4 substitutionally disordered crystal is studied by means of muon spin rotation and relaxation techniques. Measurements carried out under zero, weak transverse and longitudinal fields reveal a temperature dependence of the relaxation parameters strikingly similar to those exhibited by structural glass[Formula: see text]liquid transitions (Bermejo et al 2004 Phys. Rev. B 70 214202; Cabrillo et al 2003 Phys. Rev. B 67 184201). The observed behaviour manifests itself as a square root singularity in the relaxation rates pointing towards some critical temperature which for amorphous systems is located some tens of degrees above that shown as the characteristic transition temperature if studied by thermodynamic means. The implications of such findings in the context of current theoretical approaches concerning the canonical liquid-glass transition are discussed.Postprint (author's final draft

Dimensional reduction applied to an intelligent model for boost converter switching operation

The dimensional reduction algorithms are applied to a hybrid intelligent model that distinguishes the switching operating mode of a boost converter. Thus, the boost converter has been analyzed and both operating mode are explained, distinguishing between Hard-switching and Soft-switching modes. Then, the dataset is created out of the data obtained from simulation of the real circuit and the hybrid intelligent classification model is implemented. Finally, the dimensional reduction of the input variables is carried out and the results are compared. As result, the proposed model with the applied dimensional reduced dataset is able to distinguish between the HS and SS operating modes with high accuracy.ERDF -European Regional Development Fund(ED431G 2019/01

Modelización del costo de las empresas de inserción para la administración pública

This paper analyses a modern-day problem: the cost to government of jobs in social integration enterprises. At present there is a debate concerning their positive (subsidy-related) and negative aspects (regarding the savings they generate in social post-programmes and the revenue generated mainly by taxes and social security contributions). The study begins with an overview of social-integration enterprises, their possible development and the implication this has on the demand for public resources. In a second phase, the problem is analysed in greater detail and a possible approach is put forward based on a cost-profit analysis. The study then analyses previous research work and identifies the variables involved. Finally, a model enabling the cost analysis of the possible values of these variables is presented and hypothetical-predictive conclusions put forward.Social integration companies, cost-profit analysis, the solidarity-based economy, the social economy.

Cuticle Structure in Relation to Chemical Composition: Re-assessing the Prevailing Model

The surface of most aerial plant organs is covered with a cuticle that provides protection against multiple stress factors including dehydration. Interest on the nature of this external layer dates back to the beginning of the 19th century and since then, several studies facilitated a better understanding of cuticular chemical composition and structure. The prevailing undertanding of the cuticle as a lipidic, hydrophobic layer which is independent from the epidermal cell wall underneath stems from the concept developed by Brongniart and von Mohl during the first half of the 19th century. Such early investigations on plant cuticles attempted to link chemical composition and structure with the existing technologies, and have not been directly challenged for decades. Beginning with a historical overview about the development of cuticular studies, this review is aimed at critically assessing the information available on cuticle chemical composition and structure, considering studies performed with cuticles and isolated cuticular chemical components. The concept of the cuticle as a lipid layer independent from the cell wall is subsequently challenged, based on the existing literature, and on new findings pointing toward the cell wall nature of this layer, also providing examples of different leaf cuticle structures. Finally, the need for a re-assessment of the chemical and structural nature of the plant cuticle is highlighted, considering its cell wall nature and variability among organs, species, developmental stages, and biotic and abiotic factors during plant growth

Uprolides N, O and P from the Panamanian Octocoral Eunicea succinea.

Three new diterpenes, uprolide N (1), uprolide O (2), uprolide P (3) and a known one, dolabellane (4), were isolated from the CH₂Cl₂-MeOH extract of the gorgonian octocoral Eunicea succinea, collected from Bocas del Toro, on the Caribbean coast of Panama. Their structures were determined using spectroscopic analyses, including 1D and 2D NMR and high-resolution mass spectrometry (HRMS) together with molecular modeling studies. Compounds 1-3 displayed anti-inflammatory properties by inhibiting production of Tumor Necrosis Factor (TNF) and Interleukin (IL)-6 induced by lipopolysaccharide (LPS) in murine macrophages

Hybrid Composite-Metal Stack Drilling with Different Minimum Quantity Lubrication Levels

Hybrid stack drilling is a very common operation used in the assembly of high-added-value components, which combines the use of composite materials and metallic alloys. This process entails the complexity of machining very dissimilar materials, simultaneously, on account of the interactions that are produced between them, during machining. This study analyzed the influence of Minimum Quantity Lubrication (MQL) on the performance of diamond-coated carbide tools when drilling Ti/carbon fiber reinforced plastics (CFRP)/Ti stacks. The main wear mechanism observed was diamond-coating detachment, followed by fragile breaks in the main cutting-edge. The tests done with the lower lubrication levels have shown an important adhesion of titanium (mainly on the secondary cutting-edge) and a higher friction between the tool and the workpiece, producing higher temperatures on the cutting region and a thermal softening effect on the workpiece. These phenomena affect the evolution of cutting power consumption with tool wear in the titanium layer. Regarding the quality of the test specimen, no significant differences were observed between the lubrication levels tested.The authors acknowledge the financial support of Airbus Defense and Space, through the project Drilling Processes Improvement for Multi Material CFRP-Al-Ti Stacks, and the Ministry of Economy and Competitiveness of Spain through the grant PTA2015-10741-I and the project DPI2017-89197-C2-1-

Automatización de Procesos para mejorar las Pruebas de Software en el área de calidad del Banco de Crédito

La presente tesis se encuentra dentro de la línea de investigación de sistemas donde se orientó en la Automatización de procesos para mejorar las pruebas de software en el área de calidad del Banco de Crédito, siendo el objetivo principal, determinar en qué medida mejorará la Automatización de Procesos dentro de las Pruebas de Software en el área de calidad del Banco de Crédito. La investigación posee dos variables, la independiente: Automatización de procesos y la dependiente, pruebas de software. La investigación se estipula en el hecho de que al emplear la automatización de procesos favorece las pruebas de software mejorando la dimensión de eficiencia con el tiempo de data generada y productividad con la cantidad de data generada utilizando una herramienta llamada HP Unified Functional Testing todo ello en el área de Calidad de Software del Banco de Crédito. La metodología de investigación que se utilizó fue un enfoque cuantitativo ya que utiliza la recolección de datos para comprobar las hipótesis en fundamento en al cálculo numérico y al análisis estadístico. El tipo de investigación utilizada es aplicada y el tipo de estudio es experimental con un diseño pre-experimental, el método utilizado es el hipotético deductivo. Se utilizó las fichas de observación para poder recolectar los datos en base a la variable Procesos de Software. En base a los resultados, se concluyó que, al automatizar los procesos reducen el tiempo y aumenta la productividad para mayor beneficio del Banco de crédito, confirmando así que la automatización de procesos mejora las pruebas de software en el área de calidad del Banco de Crédito, reduciendo el tiempo de generación de data de prueba en un 56.78%, aumentando la cantidad de data generada en un 7.71 %, por lo tanto se concluye que la automatización de procesos permitió la mejora de manera significativa las pruebas de software

Influence of cutting parameters on tool wear and hole quality in composite aerospace components drilling

Composite Fiber Reinforced Plastics (CFRP) are characterized by their outstanding mechanical properties combined with reduced density and good resistance to corrosion and fatigue which make them suitable for aerospace components. During assembly procedures, one shoot drilling operations, usually including countersinking cycle, are required to minimize positional errors, enhance tight tolerances and reduce process time. Countersink drill bits were tested on CFRP test specimens, representative of aircraft components. Along testing, tool wear was monitored with an optical microscope to track its evolution and determine the dominant wear mechanism. On the other hand, hole quality was evaluated since tool life criterion is based on the assessment of machined surface quality. The influence of cutting speed and feed was analyzed with the objective of looking for extended tool life and more productive cutting parameters. The information gathered from monitoring tool wear and inspecting hole quality can be used for the enhancement of CFRP drilling and the improvement of the manufacturing process competitiveness, in terms of production cost and time.The authors acknowledge the financial support to AIRBUS DEFENCE AND SPACE through the project DRILLING PROCESSES IMPROVEMENT FOR MULTI MATERIAL CFRP-AL-TI STACKS and to the Ministry of Economy and Competitiveness of Spain through the grant with reference PTA2015-10741-I