Generalized enthalpy model of a high pressure shift freezing process

High-pressure freezing processes are a novel emerging technology in food processing, offering significant improvements to the quality of frozen foods. To be able to simulate plateau times and thermal history under different conditions, in this work we present a generalized enthalpy model of the high-pressure shift freezing process. The model includes the effects of pressure on conservation of enthalpy and incorporates the freezing point depression of non-dilute food samples. In addition the significant heat transfer effects of convection in the pressurizing medium are accounted for by solving the two-dimensional Navier-Stokes equations. We run the model for several numerical tests where the food sample is agar gel, and find good agreement with experimental data from the literature

BEC-BCS crossover in a cold and magnetized two color NJL model

The BEC-BCS crossover for a NJL model with diquark interactions is studied in the presence of an external magnetic field. Particular attention is paid to different regularization schemes used in the literature. A thorough comparison of results is performed for the case of a cold and magnetized two-color NJL model. According to our results, the critical chemical potential for the BEC transition exhibits a clear inverse magnetic catalysis effect for magnetic fields in the range $1 \lesssim eB/m_\pi^2 \lesssim 20$. As for the BEC-BCS crossover, the corresponding critical chemical potential is very weakly sensitive to magnetic fields up to $eB \sim 9\ m_\pi^2$, showing a much smaller inverse magnetic catalysis as compared to the BEC transition, and displays a strong magnetic catalysis from this point on.Comment: 15 pages, 8 figures; v2 PRD versio

Modelling and optimization of the processing of a healthy snack bar made of grape and tomato pomaces

A snack made of 36% by-products of grape and tomato pomaces was developed, also including other ingredients such as oats, chia, quinoa, honey, and peanut butter. The recipe was defined as tasty and healthy by a focus group. The snack was produced by using forced air at three different drying temperatures (50 °C, 60 °C and 70 °C). The Newton, Page, Henderson & Pabis, and Midil-li-Kucuk models fit the drying curves well. The average values for the Newton’s model drying constants were: k50= 2.71x10-1 ± 3x10-3 min-1; k60= 2. 76x10-1 ± 4x10-3 min-1 and k70= 3.91x10-1 ± 8x10-3 min-1; at 50 °C, 60 °C and 70 °C, respectively. The product’s quality was assessed over storage, regarding water activity and texture (hardness, springiness, cohesiveness, chewiness and resilience). The three tested processing temperatures did not influence the final product’s quality differently. Since there are no significant differences between initial and final water activity and texture attributes for any temperature, and they were mainly unaltered over storage, the snack bar was considered stable during this period. This new snack which includes by-products from the food industry reduces food waste and contributes to a circular economy model, simultaneously presenting environmental and economic advantages.info:eu-repo/semantics/publishedVersio

Medium-modified evolution of multiparticle production in jets in heavy-ion collisions

The energy evolution of medium-modified average multiplicities and multiplicity fluctuations in quark and gluon jets produced in heavy-ion collisions is investigated from a toy QCD-inspired model. In this model, we use modified splitting functions accounting for medium-enhanced radiation of gluons by a fast parton which propagates through the quark gluon plasma. The leading contribution of the standard production of soft hadrons is found to be enhanced by the factor $\sqrt{N_s}$ while next-to-leading order (NLO) corrections are suppressed by $1/\sqrt{N_s}$, where the nuclear parameter $N_s>1$ accounts for the induced-soft gluons in the hot medium. The role of next-to-next-to-leading order corrections (NNLO) is studied and the large amount of medium-induced soft gluons is found to drastically affect the convergence of the perturbative series. Our results for such global observables are cross-checked and compared with their limits in the vacuum and a new method for solving the second multiplicity correlator evolution equations is proposed.Comment: 21 pages and 8 figures, typo corrections, references adde

Shear-melting of a hexagonal columnar crystal by proliferation of dislocations

A hexagonal columnar crystal undergoes a shear-melting transition above a critical shear rate or stress. We combine the analysis of the shear-thinning regime below the melting with that of synchrotron X-ray scattering data under shear and propose the melting to be due to a proliferation of dislocations, whose density is determined by both techniques to vary as a power law of the shear rate with a 2/3 exponent, as expected for a creep model of crystalline solids. Moreover, our data suggest the existence under shear of a line hexatic phase, between the columnar crystal and the liquid phase

Modeling drying kinetics of dominga grapes

Air drying kinetics of grapes (Dominga variety) were determined at 30, 40 and 50°C and velocities of 0.45 and 0.60 m/s, using a pilot tunnel tray drier. The air relative humidity ranged from 3 to 35%. The characteristic drying curves presented a single falling-rate behavior. Several models were attempted to fit the drying data. The effect of temperature on grape drying kinetics was also quantified. Air velocity had no significant effect on drying rates, in the tested range. The exponential model presented the best fit, and a drying rate and equilibrium moisture content were obtained for each isothermal experiment Temperature influence on drying rate followed an Arrhenius type behavior. A one-step non-linear regression to all the data allowed to obtain an activation energy of 31.8 :!:0.3 kJ/mol and a mean equilibrium moisture content of 0.338 :!:0.007 kg water/kg d.m. The developed model is crucial for simulating drying times of Dominga grapes