Design of the Target Dump Injection Segmented (TDIS) in the framework of the High Luminosity Large Hadron Collider (HL-LHC) project

The High Luminosity Large Hadron Collider (HL-LHC) Project at CERN calls for increasing beam brightness and intensity. In this scenario, most equipment has to be redesigned and rebuilt. In particular, beam intercepting devices (such as dumps, collimators, absorbers and scrapers) have to withstand impact or scraping of the new intense HL-LHC beams without failure. Furthermore, minimizing the electromagnetic beam-device interactions is also a key design driver since they can lead to beam instabilities and excessive thermo-mechanical loading of devices. In this context, the present study assesses the conceptual design quality of the new LHC injection protection absorber, the Target Dump Injection Segmented (TDIS), from an electromagnetic and thermo-mechanical perspective. This contribution analyzes the thermo-mechanical response of the device considering two cases: an accidental beam impact scenario and another accidental scenario with complete failure of the RFcontacts. In addition, this paper presents the preliminary results from the simulation of the energy deposited by the two counter-rotating beams circulating in the device

Direct laser acceleration of electrons in free-space

Compact laser-driven accelerators are versatile and powerful tools of unarguable relevance on societal grounds for the diverse purposes of science, health, security, and technology because they bring enormous practicality to state-of-the-art achievements of conventional radio-frequency accelerators. Current benchmarking laser-based technologies rely on a medium to assist the light-matter interaction, which impose material limitations or strongly inhomogeneous fields. The advent of few cycle ultra-intense radially polarized lasers has materialized an extensively studied novel accelerator that adopts the simplest form of laser acceleration and is unique in requiring no medium to achieve strong longitudinal energy transfer directly from laser to particle. Here we present the first observation of direct longitudinal laser acceleration of non-relativistic electrons that undergo highly-directional multi-GeV/m accelerating gradients. This demonstration opens a new frontier for direct laser-driven particle acceleration capable of creating well collimated and relativistic attosecond electron bunches and x-ray pulses

Assessment of carbon monoxide formation in Fenton oxidation process: The critical role of pollutant nature and operating conditions

This work assesses the carbon monoxide formation upon Fenton process, the most popular method for Advanced Oxidation Processes (AOPs). CO concentrations in the order of 11,000 mg/Nm3 were measured in the Fenton oxidation of phenol after 180 min reaction at 90 °C and 3 bar. The Fenton oxidation performed on phenol and its oxidized intermediates such as hydroquinone, catechol and short-chain acids allows concluding that CO is produced through the oxidative cleavage of aromatic rings; the hydroquinone route being more selective to CO than catechol. In all cases, the carbon mass balance was satisfactorily closed to 100%. The study of the influence of the operational conditions shows that CO production is clearly favoured at H2O2 dosage above the stoichiometric value and low temperatures (T< 90º). The H2O2 dosage was the most influence variable. The results of this work evidence for the first time the production of noxious amounts of CO along with CO2 in Fenton processes. This finding highlights the importance of evaluating not only liquid phase intermediates due to their recalcitrant and/or toxic behavior, but also gas phase because of CO emissions.Financial support from the project CTM2016-76454-R (Ministerio de Economia y Competitividad-MINECO, Spain) is gratefully acknowledge

Numerical analysis of the vibrational behavior of the moving assembly of a dynamic loudspeaker

En este trabajo se describe el proceso llevado a cabo para analizar numéricamente mediante el método de los elementos finitos (MEF) el comportamiento vibratorio del conjunto móvil de un altavoz dinámico de bobina con doble suspensión inferior y en ausencia de la superior. El estudio se centra en el rango de baja frecuencia. El calibrado del modelo se realiza en base a medidas experimentales de la frecuencia de resonancia y desplazamiento del diafragma. Se hace énfasis en la importancia de los factores de participación asociados a la fuerza de excitación y en los cambios que se producen en estos al introducir fuerzas no equilibradas. Así mismo, el análisis proporciona datos para decidir sobre la distancia entre suspensiones, su número óptimo de pliegues y la ubicación de las trencillas, siendo estos parámetros de gran interés en el diseño de este tipo de altavoces.This paper describes the process undertaken to analyze numerically the vibrational behavior of the moving assembly of a dynamic loudspeaker with double bottom suspension and in the absence of the above one using the finite element method (FEM). The study focuses on the low frequency range. Model calibration was performed based on experimental measurements of the resonance frequency and diaphragm displacement. The importance of the participation factors associated to the excitation force and the changes produced in these when unbalanced forces are introduced are emphasized. The analysis also provides data to decide on the distance between suspensions, their optimal number of folds and the placement of the lead wires, parameters of great interest on the design of this type of loudspeakers.Peer Reviewe

LA CALIDAD Y EL CONTROL DE GESTIÓN. LA EVALUACIÓN Y LA ACREDITACIÓN

El presente trabajo implica la adaptación a nuestro ámbito universitario del instrumento elaborado por Carolyn Pearson y Low Carey , denominado por sus autoras "El perfil de motivación académica". Su aplicación resulta de utilidad para evaluar cursos universitarios con orientación docente, y contribuir por ello al mejoramiento de la calidad de la enseñanza en este nivel. Se detalla las etapas del trabajo realizado, que consisten en la re-elaboración de la escala, su aplicación y evaluación

Inversion of the anomeric configuration of the transferred sugar during inactivation of the macrolide antibiotic oleandomycin catalyzed by a macrolide glycosyltransferase

AbstractMacrolides are a group of antibiotics structurally characterized by a macrocyclic lactone to which one or several deoxy-sugar moieties are attached. The sugar moieties are transferred to the different aglycones by glycosyltransferases (GTF). The OleI GTF of an oleandomycin producer, Streptomyces antibioticus, catalyzes the inactivation of this macrolide by glycosylation. The product of this reaction was isolated and its structure elucidated. The donor substrate of the reaction was UDP-α-D-glucose, but the reaction product showed a β-glycosidic linkage. The inversion of the anomeric configuration of the transferred sugar and other data about the kinetics of the reaction and primary structure analysis of several GTFs are compatible with a reaction mechanism involving a single nucleophilic substitution at the sugar anomeric carbon in the catalytic center of the enzyme

Dengue transmission risk maps of Argentina

Dengue is an emerging disease that has become important in Argentina because of its vector's presence (Aedes aegypti) and its endemicity in neighbouring countries. Thematic maps were built for Argentina considering four main factors: population susceptibility to dengue virus infection (population density); entrance of the virus from endemic countries (main roads and airports); conditions for the vector (urbanization, altitude, minimum, maximum and mean daily temperatures) and virus extrinsic incubation period (EIP) completion in the mosquito before its death. EIP duration was modelled with a temperature-dependent function and considering life expectancies of 10, 15 and 20 days for the adult mosquito. The results show maximum risk of dengue transmission in the northern and north-eastern part of the country year-round and in the centre during the summer. Although life expectancy of the adult mosquito has a considerable influence on EIP completion, the north-east to south-west decreasing gradient is maintained. Assuming 20-day life expectancy, the EIP would be completed in almost any region of the country; whereas with 15-day life expectancy it would be limited to vector distribution area, and at 10 days it would be restricted to the northern extreme of the country.Fil:Carbajo, A.E. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.Fil:Schweigmann, N. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.Fil:De Garín, A. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.Fil:Bejarán, R. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina

Collective excitations in liquid D2 confined within the mesoscopic pores of a MCM-41 molecular sieve

We present a comparative study of the excitations in bulk and liquid D2 confined within the pores of MCM-41. The material (Mobile Crystalline Material-41) is a silicate obtained by means of a template that yields a partially crystalline structure composed by arrays of nonintersecting hexagonal channels of controlled width having walls made of amorphous SiO2. Its porosity was characterized by means of adsorption isotherms and found to be composed by a regular array of pores having a narrow distribution of sizes with a most probable value of 2.45 nm. The assessment of the precise location of the sample within the pores is carried out by means of pressure isotherms. The study was conducted at two pressures which correspond to pore fillings above the capillary condensation regime. Within the range of wave vectors where collective excitations can be followed up (0.3<Q<3.0 $\AA$&#8722;1), we found confinement brings forward a large shortening of the excitation lifetimes that shifts the characteristic frequencies to higher energies. In addition, the coherent quasielastic scattering shows signatures of reduced diffusivity.Comment: 6 page