2,559 research outputs found
Quantum Hysteresis in Coupled Light-Matter Systems
We investigate the non-equilibrium quantum dynamics of a canonical
light-matter system, namely the Dicke model, when the light-matter interaction
is ramped up and down through a cycle across the quantum phase transition. Our
calculations reveal a rich set of dynamical behaviors determined by the cycle
times, ranging from the slow, near adiabatic regime through to the fast, sudden
quench regime. As the cycle time decreases, we uncover a crossover from an
oscillatory exchange of quantum information between light and matter that
approaches a reversible adiabatic process, to a dispersive regime that
generates large values of light-matter entanglement. The phenomena uncovered in
this work have implications in quantum control, quantum interferometry, as well
as in quantum information theory.Comment: 9 pages and 4 figure
Manufacture of thermoplastic molds by fused filament fabrication 3D printing for rapid prototyping of polyurethane foam molded products
Purpose:
Polyurethane (PUR) foam parts are traditionally manufactured using metallic molds, an unsuitable approach for prototyping purposes. Thus, rapid tooling of disposable molds using fused filament fabrication (FFF) with polylactic acid (PLA) and glycol-modified polyethylene terephthalate (PETG) is proposed as an economical, simpler and faster solution compared to traditional metallic molds or three-dimensional (3D) printing with other difficult-to-print thermoplastics, which are prone to shrinkage and delamination (acrylonitrile butadiene styrene, polypropilene-PP) or high-cost due to both material and printing equipment expenses (PEEK, polyamides or polycarbonate-PC). The purpose of this study has been to evaluate the ease of release of PUR foam on these materials in combination with release agents to facilitate the mulding/demoulding process.
Design/methodology/approach:
PETG, PLA and hardenable polylactic acid (PLA 3D870) have been evaluated as mold materials in combination with aqueous and solvent-based release agents within a full design of experiments by three consecutive molding/demolding cycles.
Findings:
PLA 3D870 has shown the best demoldability. A mold expressly designed to manufacture a foam cushion has been printed and the prototyping has been successfully achieved. The demolding of the part has been easier using a solvent-based release agent, meanwhile the quality has been better when using a water-based one.
Originality/value:
The combination of PLA 3D870 and FFF, along with solvent-free water-based release agents, presents a compelling low-cost and eco-friendly alternative to traditional metallic molds and other 3D printing thermoplastics. This innovative approach serves as a viable option for rapid tooling in PUR foam molding
Dynamics of Entanglement and the Schmidt Gap in a Driven Light-Matter System
The ability to modify light-matter coupling in time (e.g. using external
pulses) opens up the exciting possibility of generating and probing new aspects
of quantum correlations in many-body light-matter systems. Here we study the
impact of such a pulsed coupling on the light-matter entanglement in the Dicke
model as well as the respective subsystem quantum dynamics. Our dynamical
many-body analysis exploits the natural partition between the radiation and
matter degrees of freedom, allowing us to explore time-dependent
intra-subsystem quantum correlations by means of squeezing parameters, and the
inter-subsystem Schmidt gap for different pulse duration (i.e. ramping
velocity) regimes -- from the near adiabatic to the sudden quench limits. Our
results reveal that both types of quantities indicate the emergence of the
superradiant phase when crossing the quantum critical point. In addition, at
the end of the pulse light and matter remain entangled even though they become
uncoupled, which could be exploited to generate entangled states in
non-interacting systems.Comment: 15 pages, 4 figures, Accepted for publication in Journal of Physics
B, special issue Correlations in light-matter interaction
Arqueología rural de época moderna y contemporánea en el entorno de Huelva : el asentamiento de "La Almagra"
En este trabajo se hace una valoración histórica y arqueológica de la Fase de ocupación de época moderna/ contemporánea documentada en la excavación del asentamiento de La Almagra, situado en los actuales terrenos del Campus universitario de El Carmen en su extremo con la Avenida de Andalucía. Es este un enclave que presenta una ocupación diacrónica que sin solución de continuidad arranca en época romana y se mantiene en funcionamiento hasta mediados del pasado siglo, donde se reproduce un modelo de poblamiento rural que parece ser el propio de la Tierra Llana onubense basado en un esquema villa rústica romana alquería islámica cortijo moderno/ contemporáneo.___________________________In this paper we make an archaeological
valuation of the modern and contemporary
phase of occupation in the settlement
kwown as La Almagra, located in the
current areas of the university of Huelva
-Campus ElCarmen- and the Avenue of
Andalucía. This settelement shows us a
continued chronological sequence form
roman period (villa rustica) to islamic and
modern/contremporary age (farmhouse).
The most significant feature in this place
is the continous exploitation of architectonical
resources leaved by every previous
moment
Carbon-based nanomaterials for gold (III) recovery: kinetics and loading investigations
Currently, the development of different smart technology to recover or eliminate strategic or toxic metals from liquid effluent is constant. Among the different process developed to the treatment of liquid effluents bearing these types of metallic elements, include chemical or electrochemical precipitation, membrane based technology, ion exchange and adsorption. Adsorption is a high efficiency, cost-effectiveness and easily handing method to recover pollutants or strategic metals. Nowadays a research challenge is the development of new adsorbents. Among nanomaterials, carbon nanomaterials have adequate properties to be used as metal adsorbent. On the other hand gold is one of the most precious elements in the world. The price in 2015 of this strategic metal is 1.376 $/kg. Besides its uses in jewellery it is highly used in different industries, so it is important the gold recovery from liquid effluents generated from these various industries. The adsorption method is a way to treat these types of effluents, characterized for their low gold concentration. The aim of this research was to optimize various operational parameters, and thus obtain efficient carbon nanotubes processing for gold (III)-bearing effluents. The adsorption of gold (III) by carbon nanofibers (CNF), carbon multiwalled (MWCN) and carbon multiwalled with carboxyl group (MWCN_ox) systems were investigated. The experimental parameters which may influence gold adsorption were investigated, i.e. stirring speed of the aqueous solutions, adsorbent dosage, acid concentration, temperature etc. Figure 1 shows the effect of the acid concentration on the Au(III) adsorption to the three adsorbent. It can be seen that the adsorption Au(III) decreases with the increase of HCl concentration. Probalby it is due the existence of other gold species, such as HAuCl4, at the higher hydrochloric solution against the presence of the predominant AuCl4- species in the more dilute HCl solutions which are more adsorbable than the gold-acid form. SEM studies of gold loaded carbon nanomaterials show on the surface dark particles, Figure 2. The EDS of the dark particles show two peaks for Lα(9.7 keV) and Mα (2.1 keV) characteristic of metallic gold. Probably this reduction occurs on the carbon surface, related with the metal reduction. The isotherm and kinetic studies of the carbon nanomaterial-Au(III) system show a different behavior in function of the carbon nanomaterial used as adsorbent. The experimental data obtained using the MWCNT and CNF fit better to a pseudo second order equation and an isotherm Freundlich model. The three carbon nanomaterials, appeared to be a promising material for recovery of Au(III) from this type of acid solutions in the optimal experimental for each one of them condition.Peer reviewe
Las células presentadoras de antígeno y su papel en el síndrome reproductivo y respiratorio porcino
Las células presentadoras de antígeno son aquellas células encargadas de capturar, procesar y presentar antígenos con la finalidad de lograr una respuesta inmune efectiva por parte del organismo. Su papel, como centinelas, es crucial durante el transcurso de diversas enfermedades infecciosas. El estudio de estas células tras la infección con el virus del Síndrome Reproductivo y Respiratorio Porcino nos da información para abordar nuevas estrategias de control frente a esta enfermedad.Antigen presenting cells are able to capture, process and present antigens in order to develop an effective immune response. The role of these cells during infectious diseases is crucial to control the disease. Thus, the study of these cells after the infection with Porcine Reproductive and Respiratory Syndrome Virus gives us useful information on how to control this disease
Bases de la respuesta inflamatoria en la forma respiratoria del PRRS
El Síndrome Reproductivo y Respiratorio Porcino (PRRS) es una enfermedad de distribución mundial que causa graves pérdidas económicas al sector porcino. Este virus no sólo es importante como agente causal del PRRS sino también por su participación en el desarrollo del Complejo Respiratorio Porcino. Su interacción con las defensas pulmonares, la alteración de la respuesta inmune y su persistencia en los órganos linfoides conlleva a que los cerdos tengan dificultades para luchar contra la enfermedad.Porcine Reproductive and Respiratory Syndrome (PRRS) is considered as the most economically important disease of the modern swine industry. The importance of this virus lies in not only being the causative agent of PRRSV, but also due to its implication in the onset of the Porcine Respiratory Disease Complex. The interaction of the virus with pulmonary defenses, the impairment of the immune response as well as the viral persistence in lymphoid organs make overcoming the disease diffi cult to infected pigs
Las industrias de salazones del litoral onubense : los casos de "El Eucaliptal" (Punta Umbría), y "El Cerro del Trigo" (Doñana, Almonte)
Una de las actividades que mejor definen la economía de época romana en el Golfo de Cádiz es la industria relacionada con la producción y comercialización de salsas de pescado (salazones). Según los testimonios arqueológicos, los orígenes de esta producción se remontan a momentos prerromanos en ámbitos geográficos relacionados con el comercio gaditano. Dado el escaso número de este tipo de instalaciones conocidas en la costa onubense durante el período romano, donde hasta la fecha sólo existían escasas referencias bibliográficas, se presentan en este trabajo los nuevos yacimientos dedicados a la producción de salazones descubiertos en prospecciones y excavaciones por el Área de Arqueología de la Universidad de Huelva, y se hace hincapié en una mayor abundancia de este tipo de instalaciones, que fenómenos geomorfológicos recientes, principalmente los donares, impiden valorar en su verdadera dispersión._____________________________One of the activities which better define the economy of Roman period in the Gulf of
Cadiz is the industry related to the production and marketing sauce of fish (fish-salting).
According to the archaeological testimonies, the origins of this production go back to preroman
moments, in areas related to the Cadiz trade.
In view of the scanty number of this type of facilities know in Huelva coast during
the Roman period, where up to the date only scanty bibliographical references existed,
there appear in this work the new deposits dedicated to the production of saltings discovered in explorations and excavations for the Area of Archaeology of the University of Huelva.
And it is emphisized a bigger abundance of this type of factories, which geomorphological
phenomenon, principally the littoral dunes system, prevent valuing at its real dispersion
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