188 research outputs found
Afinador de veu a temps real per modificació de freqüència
Aquest projecte pretén implementar un sistema que permeti afinar la veu
cantada en els casos en els que aquesta veu presenti una desafinació
respecte unes freqüències concretes, que anomenem ‘notes musicals’
Performance analysis and assessment of a highly energy-integrated solar trigeneration system using advanced absorption chillers
The direct use of solar thermal energy to generate power produces a large amount
of heat. Therefore, the use of thermally driven chillers is an appealing solution to make use
of this heat to produce cooling replacing electric driven systems. The main objective of this
paper is to provide a description of the possible designs and configurations of solar trigeneration
systems, including organic Rankine cycles (ORC) and recently commercialized advanced
absorption chillers. The main novelty of this study is the use of a Single-Effect Double-
Lift absorption cycle (SE-DL AC) for solar trigeneration cycles and its comparison with
a base case using a conventional single effect absorption cycle (SE AC). The main finding of
this study highlights that working under the same conditions; the SE-DL AC uses heat more
effectively than the SE AC for cooling production with a considerably higher production of
power at the ORC.The authors acknowledge the funding support provided by the University of Gabes for the
research stay of Mr Abdelmajid Saoud at the Universitat Rovira i Virgili in Tarragona and also
by the Spanish Ministry “Ministerio de Ciencia e Innovación” in the framework of the I+D+i
project “PDI2020-119004RB-C21”
Magnetically tunable bidirectional locomotion of a self-assembled nanorod-sphere propeller
Field-driven direct assembly of nanoscale matter has impact in disparate fields of science. In
microscale systems, such concept has been recently exploited to optimize propulsion in
viscous fluids. Despite the great potential offered by miniaturization, using self-assembly to
achieve transport at the nanoscale remains an elusive task. Here we show that a hybrid
propeller, composed by a ferromagnetic nanorod and a paramagnetic microsphere, can be
steered in a fluid in a variety of modes, from pusher to puller, when the pair is dynamically
actuated by a simple oscillating magnetic field. We exploit this unique design to build more
complex structures capable of carrying several colloidal cargos as microscopic trains that
quickly disassemble at will under magnetic command. In addition, our prototype can be
extended to smaller nanorods below the diffraction limit, but still dynamically reconfigurable
by the applied magnetic field.Peer ReviewedPostprint (published version
Numerical simulation of the alba synchrotron light source cooling system response for failure prevention
The ALBA Synchrotron Light Source cooling system is designed with a common return pipe that interconnects the four consumption rings. Such configuration is believed to compromise its optimal operation. To understand its thermo-fluid dynamic behaviour, a detailed 1D model has been built comprising all the components such as the pipes, fittings, bends, valves, pumping stations, heat exchangers and so on, and the various regulation mechanisms. Preliminarily, the model results in steady state operating conditions have been compared with experimental measurements and the maximum deviations have been found below 13%. Then, a series of transient numerical simulations have been carried out to determine the system response. Specifically, effects of the blockage and leakage of a consumption line as well as the increase and decrease of heat duty for the tunnel rings have been investigated. As a result, the stability of the system has been evaluated and the operational limits have been estimated in front of hydraulic and thermal load variations. Moreover, particular behaviours have been identified which can be used to design monitoring and control strategies to prevent unexpected failures.Postprint (published version
La relación médico-paciente en el tratamiento de la diabetes tipo 1. Un estudio cualitativo
ObjetivosConocer las experiencias y las expectativas de pacientes con diabetes tipo 1 (DM1) y sus familiares sobre la relación que establecen con sus médicos y su influencia en la forma de afrontar la enfermedad y el tratamiento.DiseñoDiseño cualitativo a través de grupos focales realizado en 2001.EmplazamientoDistintos centros sanitarios de Granada y Sevilla.ParticipantesPacientes con DM1, familiars y/o cuidadores.MétodoMuestreo teórico con representación de los perfiles más característicos. Procedimiento de análisis cualitativo: asignación de códigos al texto, triangulación e interpretación de resultados.ResultadosLa relación médico-paciente influye decisivamente en la vivencia emocional de la enfermedad y en la manera en que los pacientes asumen el control. Los pacientes entrevistados aseguran que la relación con sus médicos está centrada en los signos y los síntomas de la enfermedad, y que el aspecto emocional se deja de lado. Es frecuente que los profesionales basen su comunicación en la reprimenda y en la amenaza. Los tratamientos se imponen más que se consensúan, y las posibilidades de participación en las decisiones clínicas son escasas. En consecuencia, los pacientes desarrollan estrategias para tomar sus propias decisiones sobre el tratamiento adaptándolo a su vida.ConclusionesDesean un modelo de relación con sus médicos en el que les escuchen, empaticen con su situación, comprendan los problemas que enfrentan para seguir el tratamiento, les transmitan ánimos y adapten sus recomendaciones a las circunstancias vitales y emocionales de cada paciente. Se prefiere a los profesionales que combinan la competencia técnica (incluida la dimensión relacional) con la humanidad y la amabilidad, y que asumen su corresponsabilidad en el éxito del tratamiento.ObjectivesTo know the experiences and expectations of diabetes mellitus type 1 (DM1) patients and their relatives as regards the relationships established with doctors, and the impact of such relationships on their strategies to cope with the disease and treatment.DesignQualitative design based on focus groups conducted in 2001.LocationSeveral health care centres in Granada and Seville, Spain.ParticipantsDM1 patients and their relatives and/or carers.MethodTheory-based sampling including the most representative profiles. Qualitative analysis procedure: text coding, triangulation and interpretation of results.ResultsDoctor/patient relationship highly influences the emotional experience of disease and the way patients gain control over it. Interviewed patients said that the relationship with doctors is focused on disease signs and symptoms, leaving emotional aspects aside. Very often, provider communication is built on recrimination and threat. Treatment is imposed rather than agreed, with scarce opportunities for participating in clinical decisions. Patients develop strategies to take their own decisions and adapting treatment to their daily life.ConclusionsPatients value a relationship model whereby providers listen and empathise with their situation, understand their difficulties in treatment compliance, encourage them, and adapt recommendations to the personal and emotional circumstances of each patient. They prefer doctors combining professional competence-including relational skills-with humanity and kindness, as well as being capable of assuming their co-responsibility in treatment success
Thermo-fluid numerical simulation of the crotch absorbers’ cooling pinholes for alba storage ring
The ALBA Synchrotron Light Facility crotch absorbers, that remove the unused storage ring radiation, incorporate an internal cooling system composed by a number of parallel pinholes and by the corresponding stainless steel inner tubes inserted into each of them. Water flows in the resulting annular sections to evacuate the total heat power. Around each inner tube, a spiral wire is fixed along the whole length with a given pitch height in order to enhance the convection heat transfer. The influence of several design parameters on the absorber thermo-fluid behaviour has been evaluated by means of the CFD software ANSYS CFX¿. In particular, the wall heat transfer coefficients and the pressure losses through a single pinhole have been evaluated for a range of different flow rates and pitch heights. Moreover, some modifications of the end wall geometry have been simulated as well as the effect of reversing the flow direction inside the channels. Finally, the critical crotch absorber type 3 has also been simulated and the limiting pitch height-flow rate combinations have been found based on the available driving pressure of the cooling system.Postprint (published version
Direct measurement of Lighthill’s energetic efficiency of a minimal magnetic microswimmer
The realization of artificial microscopic swimmers able to
propel in viscous fluids is an emergent research field of fundamental
interest and vast technological applications. For
certain functionalities, the efficiency of the microswimmer
in converting the input power provided through an external
actuation into propulsive power output can be critical. Here
we use a microswimmer composed by a self-assembled
ferromagnetic rod and a paramagnetic sphere and directly
determine its swimming efficiency when it is actuated by
a swinging magnetic field. Using fast video recording and
numerical simulations we fully characterize the dynamics
of the propeller and identify the two independent degrees
of freedom which allow its propulsion. We then obtain
experimentally the Lighthill’s energetic efficiency of the
swimmer by measuring the power consumed during propulsion
and the energy required to translate the propeller at
the same speed. Finally, we discuss how the efficiency of
our microswimmer could be increased upon suitable tuning
of the different experimental parameters.Postprint (author's final draft
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