Aromatic nitrations by mixed acid. Slow liquid-liquid reaction regime

Aromatic nitrations by mixed acid have been selected as a specific case of a heterogeneous liquid-liquid reaction. An extensive experimental programme has been followed using adiabatic and heat-flow calorimetry and pilot reactor experiments, supported by chemical analysis. A series of nitration experiments has been carried out to study the influences of different initial and operating conditions such as temperature, stirring speed and sulphuric acid concentration. In parallel, a mathematical model to predict the overall conversion rate has been developed. In this paper the mathematical modelling and the implementation and experimental validation for benzene, toluene and chlorobenzene mononitration in the kinetic control regime (slow liquid-liquid reaction) are presented and discussed

Modeling of asphaltene precipitation from n-alkane diluted heavy oils and bitumens using the PC-SAFT equation of state

In this work, the PC-SAFT equation of state was applied to the modeling of asphaltene precipitation from n-alkane diluted heavy oils and bitumens. Liquid-liquid equilibrium was assumed between a dense liquid phase (asphaltene-rich phase) and a light liquid phase. The liquid-liquid equilibrium calculation, in which only asphaltenes were allowed to partition to the dense phase, was performed using an efficient method with Michelsen’s stability test. The bisection or Newton-Raphson method was used to improve convergence. Experimental information of the heavy oils and bitumens, characterized in terms of solubility fractions (saturates, aromatics, resins, and asphaltenes), was taken from the literature. Asphaltenes were divided into fractions of different molar masses using a gamma distribution function. Predictions of the PC-SAFT equation of state using linear correlations of the binary interaction parameters between asphaltene subfractions and the n-alkane were compared with the measured onset of precipitation and the amount of precipitated asphaltene (fractional yield) of the heavy oils and bitumens diluted with n-alkanes. Results of the comparison showed a satisfactory agreement between the experimental data and the calculated values with the PC-SAFT equation

Adherence to 24-Hour Movement Guidelines among Spanish Adolescents: Differences between Boys and Girls

Background: The 24-Hour Movement Guidelines for adolescents recommend >= 60 min/day of moderate-to-vigorous physical activity (PA), <= 2 h/day of screen time, and 8-10 h/day of sleep. Since little information is available on the 24-Hour Movement Guidelines in Spanish adolescents, this study aims to estimate the proportion of Spanish adolescents meeting individual and combinations of these 24-Hour Movement Guidelines. Moreover, another aim of this study is to examine gender differences in compliance with 24-Hour Movement Guidelines. Methods: A final sample of 1465 Spanish adolescents (44.50% girls; 13.08 +/- 0.86) participated in this cross-sectional study. The 24-Hour Movement Guidelines were measured during weekdays and the weekend days by self-reported questionnaires. Results: Although most adolescents met sleep duration guidelines (81.3%), only 38% and 15.8% met physical activity and screen time guidelines, respectively. Only 5.4% of these adolescents met all three 24-Hour Movement Guidelines, whereas 10.2% of this sample did not meet any of these guidelines. Although boys reported greater compliance with physical activity recommendations and girls with screen time recommendations, no significant gender differences were found in the compliance of all three 24-Hour Movement Guidelines. Conclusion: Given that 94.4% of Spanish adolescents did not meet 24-Hour Movement Guidelines, promoting all these three movement behaviours in both boys and girls is an urgent public health priority

Development of a constitutive model for the compaction of recovered polyethylene terephthalate packages

[EN] To date, PET (polyethylene terephthalate) is the most widely used plastic in packaging and also one of the most recycled polymers worldwide. However, the high transport costs and stagnated prices of recycled PET undermine recycling process profits. Transport costs can lower through compaction, which is still not a completely wellknown process. Due to heterogeneous designs, the output density of the compaction process varies. This poses problems during equipment design, selection or operation processes as recovery costs sharply increase if the required density is not met. In this manuscript, the authors develop a constitutive model for the compaction of recovered PET packaging. This experimentally validated model, based on the elasto-plastic behaviour of PET packages, allows the output density range to be predicted according to the compression pressure during PET compaction. Unlike other generic compaction models that need more than two parameters, this model uses only one and better correlates with the experimental results. Unlike existing generic models, the model parameters have a physical meaning, which allows the influence of different factors on the compaction process to be assessed. Finally as a result of the model analysis, we provide some tips to enhance compaction equipment efficiency.Funding for open access charge: CRUE-Universitat Politecnica de Valencia.Sanchez-Caballero, S.; Sellés, M.; Peydro, MA.; H.P. Cherukuri (2021). Development of a constitutive model for the compaction of recovered polyethylene terephthalate packages. Waste Management. 133:89-98. https://doi.org/10.1016/j.wasman.2021.07.028S899813

BINCOR: An r package for estimating the correlation between two unevenly spaced time series

This paper presents a computational program named BINCOR (BINned CORrelation) for estimating the correlation between two unevenly spaced time series. This program is also applicable to the situation of two evenly spaced time series not on the same time grid. BINCOR is based on a novel estimation approach proposed by Mudelsee (2010) for estimating the correlation between two climate time series with different timescales. The idea is that autocorrelation (e.g. an AR1 process) means that memory enables values obtained on different time points to be correlated. Binned correlation is performed by resampling the time series under study into time bins on a regular grid, assigning the mean values of the variable under scrutiny within those bins. We present two examples of our BINCOR package with real data: instrumental and paleoclimatic time series. In both applications BINCOR works properly in detecting well-established relationships between the climate records compared. © Technische Universitaet Wien

Disseminated epidermolytic acanthoma probably related to trauma

Epidermolytic acanthoma is a rare benign tumour, which may occur in both isolated and disseminated forms. Only seven cases of disseminated epidermolytic acanthoma (DEA) have been described. This entity should be distinguished from other hereditary or acquired conditions which involve epidermolytic hyperkeratosis and other benign acanthomas. On the basis of the clinical history and the histological findings, we diagnosed a case of DEA which was probably secondary to repeated trauma

Competition of Mesoscales and Crossover to Tricriticality in Polymer Solutions

We show that the approach to asymptotic fluctuation-induced critical behavior in polymer solutions is governed by a competition between a correlation length diverging at the critical point and an additional mesoscopic length-scale, the radius of gyration. Accurate light-scattering experiments on polystyrene solutions in cyclohexane with polymer molecular weights ranging from 200,000 up to 11.4 million clearly demonstrate a crossover between two universal regimes: a regime with Ising asymptotic critical behavior, where the correlation length prevails, and a regime with tricritical theta-point behavior determined by a mesoscopic polymer-chain length.Comment: 4 pages in RevTeX with 4 figure

Dietary patterns and total mortality in a Mediterranean cohort: the SUN project

BACKGROUND: Different dietary patterns have been associated with several health outcomes, including morbidity and mortality. There is little evidence on the association between empirically derived dietary patterns and all-cause mortality in Southern European populations. OBJECTIVE: The aim of our study was to prospectively evaluate the association between an empirically derived dietary pattern and all-cause mortality. DESIGN: The Seguimiento Universidad de Navarra (SUN) Project is an ongoing, multipurpose, prospective and dynamic Spanish cohort. PARTICIPANTS/SETTING: Participants were a prospective cohort of 16,008 middle-aged Spanish adults. All of them were university graduates (alumni) (59.6% women, mean age 38 years). Usual diet was assessed at baseline with a validated semiquantitative food frequency questionnaire. MAIN OUTCOME MEASURES: Deaths were confirmed by review of medical records and of the National Death Index. STATISTICAL ANALYSIS: Dietary patterns were ascertained through a factor (principal component) analysis based on 30 predefined food groups. Participants were classified according to tertiles of adherence to the three main dietary patterns identified with factor analysis. Cox regression models were fitted to estimate multivariable-adjusted hazard ratios and 95% CIs for mortality. RESULTS: Three major dietary patterns were identified. They were labelled Western dietary pattern (rich in red and processed meat, potatoes, and fast food), Mediterranean dietary pattern (rich in vegetables, fish and seafood, fruits, and olive oil), and alcoholic beverages dietary pattern. During follow-up, 148 deaths were reported (mean age at death 54.5 years). After adjustment for potential confounders, the lowest risk of all-cause mortality was found in the tertile of highest adherence to the Mediterranean dietary pattern (adjusted hazard ratio for third vs first tertile 0.53, 95% CI 0.34 to 0.84) (P for trend <0.01). The Western dietary pattern and alcoholic beverages dietary pattern showed no significant association with mortality. CONCLUSIONS: Greater adherence to an empirically derived dietary pattern approaching the traditional Mediterranean diet was associated with a reduction in the risk of all-cause mortality among middle-aged Mediterranean adults