Effect of different temperature–time combinations on physicochemical,microbiological, textural and structural features of sous-vide cooked lamb loins

Lamb loins were subjected to sous-vide cooking at different combinations of temperature (60, 70, and 80 °C) and time (6, 12, and 24 h). Different physicochemical, histological and structural parameters were studied. Increasing cooking temperatures led to higher weight losses and lower moisture contents, whereas the effect of cooking time on these variables was limited. Samples cooked at 60 °C showed the highest lightness and redness, while increasing cooking temperature and cooking time produced higher yellowness values. Most textural variables in a texture profile analysis showed a marked interaction between cooking temperature and time. Samples cooked for 24 h showed significantly lower values for most of the studied textural parameters for all the temperatures considered. Connective tissue granulation at 60 °C and gelation at 70 °C were observed in the SEM micrographs. The sous-vide cooking of lamb loins dramatically reduced microbial population even with the less intense heat treatment studied (60 °C–6 h).     

Physicochemical properties of ready‐to‐eat extruded nixtamalized maize‐based snacks enriched with grasshopper

The aim of this research was to prepare an extruded snack based on nixtamalized maize flour (Zea mays L.) (NMF) enriched with grasshopper meal (Sphenarium purpurascens Ch.) (GM) using a single screw extruder with a compression screw ratio of 3:1. A central experimental design comprising three independent variables, namely, extrusion temperature (T = 120–180 °C), feed moisture content (FMC = 18–22 g/100 g) and the grasshopper meal proportion (GMP = 0–40 g/100 g), was used. Increasing T decreased (P < 0.05) the expansion index (EI), bulk density (BD) and hardness (H). Increasing the FMC increased (P < 0.05) the EI. Increasing the GMP decreased (P < 0.05) the EI, H and water absorption index (WAI) and increased (P < 0.05) the BD and total colour difference (ΔE). The treatments that resulted in better general acceptability were those that contained a lower GMP. An extruded snack acceptable to the consumer can be obtained from a blend of NMF and GM, and up to 8.11 g/100 g of GM can be incorporated without affecting the physicochemical properties and acceptance of the snack.     

Beacon-less geographic routing made practical: challenges, design guidelines, and protocols - [Topics in ad hoc and sensor networks]

Geographic routing has emerged as one of the most efficient and scalable routing solutions for wireless sensor networks. In traditional geographic routing protocols, each node exchanges periodic one-hop beacons to determine the position of its neighbors. Recent studies proved that these beacons can create severe problems in real deployments due to the highly dynamic and error-prone nature of wireless links. To avoid these problems, new variants of geographic routing protocols that do not require beacons are being proposed. In this article we review some of the latest proposals in the field of beacon-less geographic routing and introduce the main design challenges and alternatives. In addition, we perform an empirical study to assess the performance of beacon-based and beacon-less routing protocols using a real WSN deployment.     

Rheological behaviour of concentrated mandarin juice at low temperatures

Several rheological properties of concentrated mandarin juice were investigated, quantifying thixotropic behaviour and fitting experimental data to the Hahn, Weltman, and Figoni–Shoemaker equations. The latter one proved best for modelling the time dependency response. Pseudoplastic behaviour fitted well with the Herschel–Bulkley model in the interval between ?12 and 6 °C, in which yield stress and the flow behaviour index scarcely changed with temperature. The consistency coefficient and apparent viscosity both decreased as temperature increased. Fitting these consistency data to the Arrhenius‐type equation, a value of 33 kJ mol^?1 for activation energy was obtained. Concentrated mandarin juice displayed viscoelastic properties in the temperature range between ?12 and 6 °C, with the elastic character (determined by the juice’s pectin content) predominating over the viscous nature at low frequency values, but with this behaviour being inverted for high values. Furthermore, as the temperature became higher, the elastic character became more important than the viscous nature.     

“Click” Synthesis of a Heterobifunctional Ferrocenyl Dendrimer with Molecular Recognition Properties and Influence of the Ferrocenyl Redox Potential on the Formation of Gold Nanoparticles

Alkyne protection by complexation of ethynylferrocene with dicobalt octacarbonyl followed by regioselective acetylation, then deprotection and “click” reaction with a nona-azido-terminated arene-cored dendrimer leads to the heterodifunctional nona(1,2,3-triazolyl-acetylferrocenyl) dendrimer. Cyclic voltammetry of this metallodendrimer shows recognition of both ATP^2? and Pd²⁺. HAuCl₄ is reduced much more slowly to gold nanoparticles by the nona(triazolyl-acetylferrocenyl dendrimer than by the nona(triazolylferrocenyl) dendrimer due to the shift of redox potential in the new heterodifunctional dendrimer compared to that of the parent ferrocenyl dendrimer.     

Restarted Iterated Pareto Greedy algorithm for multi-objective flowshop scheduling problems

Multi-objective optimisation problems have seen a large impulse in the last decades. Many new techniques for solving distinct variants of multi-objective problems have been proposed. Production scheduling, as with other operations management fields, is no different. The flowshop problem is among the most widely studied scheduling settings. Recently, the Iterated Greedy methodology for solving the single-objective version of the flowshop problem has produced state-of-the-art results. This paper proposes a new algorithm based on Iterated Greedy technique for solving the multi-objective permutation flowshop problem. This algorithm is characterised by an effective initialisation of the population, management of the Pareto front, and a specially tailored local search, among other things. The proposed multi-objective Iterated Greedy method is shown to outperform other recent approaches in comprehensive computational and statistical tests that comprise a large number of instances with objectives involving makespan, tardiness and flowtime. Lastly, we use a novel graphical tool to compare the performances of stochastic Pareto fronts based on Empirical Attainment Functions.     

Optimal and heuristic solution methods for a multiprocessor machine scheduling problem

This paper deals with the scheduling of operations on a multiprocessor machine in the context of shoe manufacturing. Multiprocessor machines are composed of several parallel processors. Unlike parallel machines, the entire machine needs to be stopped whenever a single processor needs a setup. Our industrial partner, one of the major winter-shoe manufacturers in Canada, offers a relatively large variety of models. For each of these models, all the sizes proposed by this manufacturer must be produced in various quantities. Our objective is to schedule the production of the required sizes on the machine's different processors in order to minimize the global makespan, which includes both the production time and the set up time. We first present a mathematical formulation of the problem. Then, we introduce a decomposition procedure based on the mathematical model, and we demonstrate that this procedure is very efficient for small- and medium-size instances. We also propose two construction heuristics and two improvement heuristics for larger problems, and we report the results of our extensive computational experiments to demonstrate the quality of the proposed heuristics in terms of reducing production time and computational effort.     

Utilization of Ultrasonic Measurements for Determining the Variations in Microstructure of Thermally Degraded 2205 Duplex Stainless Steel

The aim of this study is to investigate the changes in attenuation of longitudinal waves and velocity of shear wave modes for assessing variations in the microstructure of thermally degraded 2205 duplex stainless steel samples that were aged isothermally at 700°C and 900°C for different time intervals. The evaluation of material microstructural changes such as phase transformation and second phase precipitation which are related to material properties is of primary importance to ensure quality of components. This paper presents evidence that indicate that the attenuation coefficient of the longitudinal mode is sensitive to gradual microstructural changes produced by the aging treatments. The gradual changes in microstructure are associated with reduction of impact properties. On the other hand, for samples aged at 700°C, the velocity of the fast mode of shear wave show changes at high aging times and does not show changes at early aging times were the materials properties are already degraded.     

Impact of Storm-Water Runoff on Clogging and Fecal Bacteria Reduction in Sand Columns

Storm-water runoff has been identified as a major cause of coastal water quality degradation. Storm-water outfalls, common in many coastal towns, convey bacteria and other pollutants into the ocean and estuaries. In an effort to minimize this impact, the Town of Kure Beach, North Carolina, installed Dune Infiltration Systems (DIS) at two storm-water outfalls to receive storm-water runoff and allow infiltration beneath the beach dunes. A laboratory column experiment was performed to supplement this installation and determine the potential hydraulic and bacterial removal efficiency of the sand comprising the Kure Beach dunes. Columns constructed using sand collected at different depths of the dune were used to analyze the affect of bacteria application on infiltration and to examine the changes in bacteria removal that occur as infiltration rates are affected by bacteria-laden water application. Sand columns were loaded over a 60-day period with either bacteria-free storm water or storm water spiked with Escherichia coli. The seepage rate for the bacteria-spiked storm-water treatment was significantly lower (p<0.05) than the seepage rate of the bacteria-free treatment, particularly toward the end of the study. Bacteria application likely compounds the impact of sediment clogging at the sand/storm-water interface. This study indicates the need for maintenance when implementing a DIS or similar sand filter to maintain design infiltration rates, especially if reduced infiltration rates are not planned for in the design. However, a decrease in seepage rate was correlated with a decrease in effluent bacteria concentration in the bacteria-spiked storm-water sand columns. Thus, optimization is required to provide maximum infiltration of storm-water while maintaining bacteria removal efficiency.