A food and beverage map: Exploring food-beverage pairing through projective mapping

acceptedVersio

Infinite-range Ising ferromagnet in a time-dependent transverse field: quench and ac dynamics near the quantum critical point

We study an infinite range ferromagnetic Ising model in the presence of a transverse magnetic field which exhibits a quantum paramagnetic-ferromagnetic phase transition at a critical value of the transverse field. In the thermodynamic limit, the low-temperature properties of this model are dominated by the behavior of a single large classical spin governed by an anisotropic Hamiltonian. Using this property, we study the quench and AC dynamics of the model both numerically and analytically, and develop a correspondence between the classical phase space dynamics of a single spin and the quantum dynamics of the infinite-range ferromagnetic Ising model. In particular, we compare the behavior of the equal-time order parameter correlation function both near to and away from the quantum critical point in the presence of a quench or AC transverse field. We explicitly demonstrate that a clear signature of the quantum critical point can be obtained by studying the AC dynamics of the system even in the classical limit. We discuss possible realizations of our model in experimental systems.Comment: Revtex4, 10 pages including 10 figures; corrected a sign error in Eq. 32; this is the final published versio

Pairing beer and food in social media: Is it an image worth more than a thousand words?

Food pairing has been widely studied to understand the patterns that explain how people pair different foods and ingredients and, therefore, to obtain successful pairings and good recommendations for consumers. Social media has become a common way of exchanging information; therefore, we proposed to use it as a tool for exploring beer-food pairing and eating behavior. Twitter and Instagram were selected as they are among the most popular platforms. Although texts from Twitter could provide an accurate verbal description of consumer's food experiences, Instagram could offer the possibility of exploring the consumption context through images, leading to a better understanding of consumers' eating behavior, with a focus on food and beverage combinations. We hypothesize that images from Instagram will provide further information than texts from Twitter, regarding beer-food pairing and consumption context. A social media study was performed in Mexico comparing texts vs. images, selected from a one-year period, and manually classified through content analysis. Foods extracted from images and texts were categorized into frequencies and analyzed using multiple correspondence analysis (MCA) and hierarchical clustering (AHC). MCA showed the most frequently mentioned foods paired with beer for each platform. Data extracted from images and texts about consumption context was also analyzed and categorized into frequencies according to several themes: consumption behavior, type of consumption, way of beer consumption, place of consumption, and consumption occasion. Data extracted from the two platforms was compared by using a chi-square test per theme. Several differences were found, depending on the social media platform, texts being the one with less extracted and meaningful information. In general, while texts provided less extracted and meaningful information, images offered more details regarding beer-food pairing and context of consumption, the same as beer information such as type, color, brand, and style. Overall, images gave more information on beer-food pairing compared to texts. The methods and results from this paper could be applied by culinary professionals, sommeliers, and researchers in the gastronomy and food and hospitality areas.acceptedVersio

Extreme durability of wettability changes on polyolefin surfaces by atmospheric pressure plasma torch

In the present work three common polyolefins: high density polyethylene (HDPE), low density polyethylene (LDPE) and polypropylene (PP) have been treated with an atmospheric pressure air plasma torch (APPT) in order to improve their wettability properties. The variations in surface energy (γs), as well as the durability of the treatment are determined by means of contact angle measurements for different aging times after plasma exposure (up to 270 days) using five test liquids which cover a wide range of polarities. The introduction of new polar moieties (carbonyl, amine or hydroxyl) is confirmed by Fourier transform infrared spectroscopy in attenuated total multiple reflection mode (ATR-FTIR) and X-ray photoelectron spectroscopy (XPS). Furthermore, scanning electron microscopy (SEM) provides information on the morphological changes and variation on surface roughness, revealing that smoother, lamellar and semispheric micrometric structures are created on the LDPE, HDPE and PP surfaces, respectively. Results show that APPT treatment enhances both the total and polar components of the gammas under study, with an unprecedent stability (> 8 months) in time.Financial support from the Fundación Universidad Carlos III de Madrid e Instituto Tecnológico de Química y Materiales “Álvaro Alonso Barba” is acknowledged. Authors also acknowledge MCI for the financial support to the project MAT2006 11614 C03 02

Numerical Study of a Mixed Ising Ferrimagnetic System

We present a study of a classical ferrimagnetic model on a square lattice in which the two interpenetrating square sublattices have spins one-half and one. This model is relevant for understanding bimetallic molecular ferrimagnets that are currently being synthesized by several experimental groups. We perform exact ground-state calculations for the model and employ Monte Carlo and numerical transfer-matrix techniques to obtain the finite-temperature phase diagram for both the transition and compensation temperatures. When only nearest-neighbor interactions are included, our nonperturbative results indicate no compensation point or tricritical point at finite temperature, which contradicts earlier results obtained with mean-field analysis.Comment: Figures can be obtained by request to [email protected] or [email protected]

Atmospheric pressure plasma hydrophilic modification of a silicone surface

Presented in part at the 1st International Conference on Structural Adhesive Bonding (AB2011), Porto, Portugal, 7-8 July 2011.The aim of this study was the creation of a silicone hydrophilic surface prior to bonding. Modifications in wettability and adhesion properties of silicone were performed with an atmospheric plasma torch (APPT). Surface energy variations of the substrate, both pristine and APPT-treated, were evaluated through contact angle measurements, studying the hydrophobic recovery of the samples up to 24 hours of aging. Compositional and topographical changes induced by APPT and aging were studied by attenuated total multiple reflection mode infrared spectroscopy (ATR-FTIR), X-ray photoelectron spectroscopy (XPS), mechanical profilometry, scanning electron microscopy (SEM), and atomic force microscopy (AFM), respectively. Adhesion pull-off tests were performed on silicone-aluminium stud joints using three commercial adhesives, which were Sikaflex®-252, polyurethane-based, Loctite®-330, urethane methacrylate ester-based acrylic, and Terostat®-922, modified silicone. Although experimental data of all the bonding specimens led to an undesired adhesive failure, it was found that APPT-treated samples gave higher adhesive strength than the pristine ones, which was explained by the higher surface energy, thus more wettable material, after APPT. This effect remained stable for just 1 h, when the substrate began its hydrophobic recovery, reaching the original surface energy values after 24 h of aging.Financial support from the Universidad Carlos III de Madrid Foundation and Chemistry and Materials Technological Institute ‘‘Álvaro Alonso Barba’’ are acknowledged, as well as from the Universidad Pontificia Comillas (ICAI) (Spain)

Response of a catalytic reaction to periodic variation of the CO pressure: Increased CO_2 production and dynamic phase transition

We present a kinetic Monte Carlo study of the dynamical response of a Ziff-Gulari-Barshad model for CO oxidation with CO desorption to periodic variation of the CO presure. We use a square-wave periodic pressure variation with parameters that can be tuned to enhance the catalytic activity. We produce evidence that, below a critical value of the desorption rate, the driven system undergoes a dynamic phase transition between a CO_2 productive phase and a nonproductive one at a critical value of the period of the pressure oscillation. At the dynamic phase transition the period-averged CO_2 production rate is significantly increased and can be used as a dynamic order parameter. We perform a finite-size scaling analysis that indicates the existence of power-law singularities for the order parameter and its fluctuations, yielding estimated critical exponent ratios $\beta/\nu \approx 0.12$ and $\gamma/\nu \approx 1.77$. These exponent ratios, together with theoretical symmetry arguments and numerical data for the fourth-order cumulant associated with the transition, give reasonable support for the hypothesis that the observed nonequilibrium dynamic phase transition is in the same universality class as the two-dimensional equilibrium Ising model.Comment: 18 pages, 10 figures, accepted in Physical Review

Low-temperature nucleation in a kinetic Ising model with soft stochastic dynamics

We study low-temperature nucleation in kinetic Ising models by analytical and simulational methods, confirming the general result for the average metastable lifetime, = A*exp(beta*Gamma) (beta = 1/kT) [E. Jordao Neves and R.H. Schonmann, Commun. Math. Phys. 137, 209 (1991)]. Contrary to common belief, we find that both A and Gamma depend significantly on the stochastic dynamic. In particular, for a ``soft'' dynamic, in which the effects of the interactions and the applied field factorize in the transition rates, Gamma does NOT simply equal the energy barrier against nucleation, as it does for the standard Glauber dynamic, which does not have this factorization property.Comment: 4 pages RevTex4, 2 figures. Phys. Rev. Lett., in pres

Dynamic Phase Transition in a Time-Dependent Ginzburg-Landau Model in an Oscillating Field

The Ginzburg-Landau model below its critical temperature in a temporally oscillating external field is studied both theoretically and numerically. As the frequency or the amplitude of the external force is changed, a nonequilibrium phase transition is observed. This transition separates spatially uniform, symmetry-restoring oscillations from symmetry-breaking oscillations. Near the transition a perturbation theory is developed, and a switching phenomenon is found in the symmetry-broken phase. Our results confirm the equivalence of the present transition to that found in Monte Carlo simulations of kinetic Ising systems in oscillating fields, demonstrating that the nonequilibrium phase transition in both cases belongs to the universality class of the equilibrium Ising model in zero field. This conclusion is in agreement with symmetry arguments [G. Grinstein, C. Jayaprakash, and Y. He, Phys. Rev. Lett. 55, 2527 (1985)] and recent numerical results [G. Korniss, C.J. White, P. A. Rikvold, and M. A. Novotny, Phys. Rev. E (submitted)]. Furthermore, a theoretical result for the structure function of the local magnetization with thermal noise, based on the Ornstein-Zernike approximation, agrees well with numerical results in one dimension.Comment: 16 pp. RevTex, 9 embedded ps figure

Absence of First-order Transition and Tri-critical Point in the Dynamic Phase Diagram of a Spatially Extended Bistable System in an Oscillating Field

It has been well established that spatially extended, bistable systems that are driven by an oscillating field exhibit a nonequilibrium dynamic phase transition (DPT). The DPT occurs when the field frequency is on the order of the inverse of an intrinsic lifetime associated with the transitions between the two stable states in a static field of the same magnitude as the amplitude of the oscillating field. The DPT is continuous and belongs to the same universality class as the equilibrium phase transition of the Ising model in zero field [G. Korniss et al., Phys. Rev. E 63, 016120 (2001); H. Fujisaka et al., Phys. Rev. E 63, 036109 (2001)]. However, it has previously been claimed that the DPT becomes discontinuous at temperatures below a tricritical point [M. Acharyya, Phys. Rev. E 59, 218 (1999)]. This claim was based on observations in dynamic Monte Carlo simulations of a multipeaked probability density for the dynamic order parameter and negative values of the fourth-order cumulant ratio. Both phenomena can be characteristic of discontinuous phase transitions. Here we use classical nucleation theory for the decay of metastable phases, together with data from large-scale dynamic Monte Carlo simulations of a two-dimensional kinetic Ising ferromagnet, to show that these observations in this case are merely finite-size effects. For sufficiently small systems and low temperatures, the continuous DPT is replaced, not by a discontinuous phase transition, but by a crossover to stochastic resonance. In the infinite-system limit the stochastic-resonance regime vanishes, and the continuous DPT should persist for all nonzero temperatures