Assessment of chemical and microbiological parameters of indoor swimming pool atmosphere using multiple comparisons

The aim of this study was to evaluate the air quality of an indoor swimming pool, analyzing diurnal and seasonal variations in microbiological counts and chemical parameters. The results indicated that yeast and bacteria counts, as well as carbon dioxide (CO₂), nitrogen oxides (NO_x) and O₃ concentrations, showed significant diurnal difference. On the other hand, temperature, relative humidity (R.H.), yeast counts and concentrations of CO₂, particles, O₃, toluene, and benzene showed seasonal differences. In addition, the relationship between indoor and outdoor air and the degree of correlation between the different parameters have been calculated, suggesting that CO₂, fine particles and NO_x would have indoor origin due to the human activity and secondary reactions favored by the chemical and environmental conditions of the swimming pool; while O₃, benzene and toluene, would come from outside, mainly. The overall results indicated that indoor air quality (IAQ) in the swimming pool building was deficient by the high levels of CO₂ and microorganisms, low temperatures, and high R.H., because frequently the limits established by the legislation were exceeded. This fact could be due to the poor ventilation and the inadequate operation of heating, ventilation, and air‐conditioning systems.     

Influence of physicochemical binder properties on agglomeration of wheat powder in couscous grain

Wet agglomeration mechanisms developing in low shear mixers have been described considering a fractal morphogenesis process that links the median size of the agglomerates with their solid volume fraction via a fractal dimension. It appears fundamental to integrate the polydispersity of the generated structures (nuclei, agglomerates, dough pieces) in the analysis of the agglomeration process in order to approach the industrial problems. The objective of this study is to correlate the influence of the physicochemical characteristics of several liquid binders, on the fractal agglomeration mechanisms. To do so, we considered the values of the fractal model parameters. The obtained results confirmed that semolina wet agglomeration follows a fractal morphogenesis for the different applied liquid binders. Our results also showed a marked influence of the studied physicochemical properties of the liquid binder on the value of the fractal model parameters. During wet agglomeration in low shear mixers, the mechanisms implied during agglomeration (wetting, nucleation and growth) do not occur consecutively, but they coexist throughout at each water contents.     

In vitro digestibility of phenolic compounds from edible fruits: could it be explained by chemometrics?

The health benefits of phenolic compounds depend on the ingested amount, molecular diversity and gastrointestinal digestibility. The phenolic profile of eight fruits (blackberry, blueberry, strawberry, raspberry, mulberry, pomegranate, green and red globe grapes) was chemometrically associated with their in vitro digestibility (oral, gastric, intestinal). Extractable phenols, flavonoids and anthocyanins strongly correlated with each other (r ≥ 0.84), proanthocyanidins with anthocyanins (r = 0.62) and hydrolysable phenols with both extractable phenols (r = 0.45) and proanthocyanidins (r = ?0.54). Two principal components explained 93% of the variance [61% (free‐phenols), 32% (bounded‐phenols)], and four clusters were confirmed by hierarchical analysis, based in their phenolic richness (CLT 1‐4: low to high) and molecular diversity. In vitro digestibility of extractable phenols and flavonoids was blackberry (CLT‐4)> raspberry (CLT‐2)> red grape (CLT‐1) related to their phenolic richness (r ≥ 0.96; P < 0.001), but anthocyanins’ digestibility was pH‐dependent. Chemometrics is useful to predict the in vitro digestibility of phenolic compounds in the assayed fruits.     

Scheduling unrelated parallel machines with optional machines and jobs selection

In this paper we study two generalizations of the well known unrelated parallel machines scheduling problem under makespan (C_max) minimization. First, a situation in which not every available parallel machine should be used and it is desirable to employ only a subset of the parallel machines. This is referred to as “Not All Machines” or NAM in short. This environment applies frequently in production shops where capacity exceeds demand or when production capacity can be lent to third companies. Also, NAM can be used to increase production capacity and it is not clear how many additional machines should be acquired. The second studied generalization has been referred to as “Not All Jobs” or NAJ. Here, there is no obligation to process all available jobs. We propose Mixed Integer Programming mathematical formulations for both NAM and NAJ, and it is shown that the latter can be effectively solved with modern commercial solvers. We also present three algorithms to solve the NAM problem. These algorithms are compared with the proposed MIP formulation when solved with IBM ILOG CPLEX 12.1. Comprehensive computational and statistical experiments prove that our proposed algorithms significantly improve the results given by the solver.