Biosorption of Phenol onto Posidonia oceanica (L.) Seagrass in Batch System: Equilibrium and Kinetic Modelling

In this research, the biosorption of phenol using the fibres of a Mediterranean seagrass Posidonia oceanica (L.) was studied. Batch experimental procedures were made to investigate the ability of this novel marine biomass to remove phenol from aqueous phase. The influences of pH and contact time at different initial concentrations were evaluated. The results showed that biosorption capacity was enhanced using solution pH equal to 5.2. The modelling results showed that pseudo‐second‐order and Redlich‐Peterson models were found to be the most suitable to satisfactory describe the kinetic and equilibrium adsorption data, respectively.     

Kinetics and mechanism of ferrous spinel oxidation studied by electrical conductivity and thermogravimetry

A mechanism of valence transfer between Fe²⁺ and Fe³⁺ ions in the octahedral, as well as the tetrahedral position of the spinel lattice is suggested to account for the electrical behaviour with the number of Fe²⁺-Fe³⁺ pairs in either position for oxidation reactions in finely-grained ferrous spinels. From the =f(t) curves which are identified with those obtained in thermogravimetry, it was established for inverse spinels such as Fe₃O₄ or for normal spinels such as FeCr₂O₄ that the kinetics is governed by a diffusion law under variable working conditions. For more complex spinels such as chromium-or titanium-substituted magnetites which exhibit both Fe²⁺ ions on octahedral and tetrahedral sites, the results are discussed only qualitatively although the profile of the =f(t) curves can also be related to the electronic exchange between the Fe²⁺ and Fe³⁺ ions from the two cation sites.     

3D Target Scale Estimation and Target Feature Separation for Size Preserving Tracking in PTZ Video

To achieve size preserving tracking, in addition to controlling the camera’s pan and tilt motions to keep the object of interest in the camera’s field of view (FOV), the camera’s focal length is adjusted automatically to compensate for the changes in the target’s image size caused by the relative motion between the camera and the target. The estimation accuracy of these changes determines the effectiveness of the resulting zoom control. The existing method of choice for real-time target scale estimation applies structure from motion (SFM) based on the weak perspective projection model. In this paper we propose a target scale estimation algorithm with a linear solution based on the more advanced paraperspective projection model, which improves the accuracy of scale estimation by considering center offset. Another key issue in SFM based algorithms is the separation of target and background features, especially when composite camera (pan/tilt/zoom) and target motions are involved. This paper designs a fast target feature separation/grouping algorithm, the 3D affine shape method. The resulting separation automatically adapts to the target’s 3D geometry and motion and is able to accommodate a large amount of off-plane rotation, which most existing separation/grouping algorithms find difficult to achieve. Experimental results illustrate the effectiveness of the proposed scale estimation and feature separation algorithms in tracking translating and rotating objects with a PTZ camera while preserving their sizes. In comparison with the leading size preserving tracking algorithm described by Tordoff and Murray, our algorithm is able to reduce the cumulative tracking error significantly from 17.4% to 3.3%.     

C/C-SiC component for metallic phase change materials

Thanks to their high energy density and thermal conductivity, metallic Phase Change Materials (mPCM) have shown great potential to improve the performance of thermal energy storage systems. However, the commercial application of mPCM is still limited due to their corrosion behavior with conventional container materials. This work first addresses on a fundamental level, whether carbon-based composite-ceramics are suitable for corrosion critical components in a thermal storage system. The compatibility between the mPCM AlSi₁₂ and the Liquid Silicon Infiltration (LSI)-based carbon fiber reinforced silicon carbide (C/C-SiC) composite is then investigated via contact angle measurements, microstructure analysis, and mechanical testing after exposure. The results reveal that the C/C-SiC composite maintains its mechanical properties and microstructure after exposure in the strongly corrosive mPCM. Based on these results, efforts were made to design and manufacture a container out of C/C-SiC for the housing of mPCM in vehicle application. The stability of the component filled with mPCM was proven nondestructively via computer tomography (CT). Successful thermal input- and output as well as thermal storage ability were demonstrated using a system calorimeter under conditions similar to the application. The investigated C/C-SiC composite has significant application potential as a structural material for thermal energy storage systems with mPCM.     

Isothermal section of the Er–Fe–Al ternary system at 800 °C

Physico-chemical analysis techniques, including X-ray diffraction and Scanning Electron Microscope–Energy Dispersive X-ray Spectroscopy, were employed to construct the isothermal section of the Er–Fe–Al system at 800 °C. At this temperature, the phase diagram is characterized by the formation of five intermediate phases, ErFe_12?xAl_x with 5 ≤ x ≤ 8 (ThMn₁₂-type), ErFe_1+xAl_1?x with ?0.2 ≤ x ≤ 0.75 (MgZn₂-type), ErFe_3?xAl_x with 0.5 < x ≤ 1 (DyFe₂Al-type), Er₂Fe_17?xAl_x with 4.74 ≤ x ≤ 5.7 (TbCu₇-type) and Er₂Fe_17?xAl_x with 5.7 < x ≤ 9.5 (Th₂Zn₁₇-type), seven extensions of binaries into the ternary system; ErFe_xAl_3?x with x < 0.5 (Au₃Cu-type), ErFe_xAl_2?x with x ≤ 0.68 (MgCu₂-type), Er₂Fe_xAl_1?x with x ≤ 0.25 (Co₂Si-type), ErFe_2?xAl_x with x ≤ 0.5 (MgCu₂-type), ErFe_3?xAl_x with x ≤ 0.5 (Be₃Nb-type), Er₆Fe_23?xAl_x with x ≤ 8 (Th₆Mn₂₃-type), and Er₂Fe_17?xAl_x with x ≤ 4.75 (Th₂Ni₁₇-type) and one intermetallic compound; the ErFe₂Al₁₀ (YbFe₂Al₁₀-type).     

Tight bounds for the identical parallel machine scheduling problem

We address the problem of minimizing makespan on identical parallel machines. We propose new lower bounding strategies and heuristics for this fundamental scheduling problem. The lower bounds are based on the so‐called lifting procedure. In addition, two optimization‐based heuristics are proposed. These heuristics require iteratively solving a subset‐sum problem. We present the results of computational experiments that provide strong evidence that the new proposed lower and upper bounds consistently outperform the best bounds from the literature.     

Extraction of phenolic compounds from Vitex agnus-castus L.

The primary objective of this study was to valorized Vitex agnus-castus residues in terms of phenolic compounds. The effects of extraction time (30–360 min), solid to liquid ratio (0.1–0.3 g_DryBiomass/ml_Solvent), type of solvent and different tissue types (leave, roots and seeds) on total polyphenols, o-diphenols, total flavonoids and anthocyanins were evaluated. The highest total polyphenol (31.5 mg_{CaffeicAcidEquivalent}/g_DryBiomass) and o-diphenol (12.4 mg_{CaffeicAcidEquivalent}/g_DryBiomass) contents were obtained from methanolic extract of leaves after 180 min using a solid/liquid ratio of 0.1 g_DryBiomass/ml_Solvent, while total flavonoids, reached a maximum value of 19.4 mg_{CatechinEquivalent}/g_DryBiomass after 360 min under the same conditions. Roots of V. agnus-castus were found to be a good source of anthocyanins with the highest yield of 0.62 mg_{MalvidinEquivalent}/g_DryBiomass using ethanol as a solvent (180 min and 0.2 g_DryBiomass/ml_Solvent). The maximum antiradical power (178.5 μl_extract/μg_DPPH) was exhibited by the methanolic leave extract obtained after 360 min at solid/liquid ratio of 0.3 g_DryBiomass/ml_Solvent.     

Tight bounds for the identical parallel machine-scheduling problem: Part II

A companion paper introduces new lower bounds and heuristics for the problem of minimizing makespan on identical parallel machines. The objective of this paper is threefold. First, we describe further enhancements of previously described lower bounds. Second, we propose a new heuristic that requires solving a sequence of 0–1 knapsack problems. Finally, we show that embedding these newly derived bounds in a branch‐and‐bound procedure yields a very effective exact algorithm. Moreover, this algorithm features a new symmetry‐breaking branching strategy. We present the results of computational experiments that were carried out on a large set of instances and that attest to the efficacy of the proposed algorithm. In particular, we report proven optimal solutions for some benchmark problems that have been open for some time.     

A chemical assay method for the determination of aflatoxin residues in animal tissues

A method is presented for the determination of aflatoxins in animal tissues. It consists of extraction of aflatoxins from the sample with methanol, treatment of the residue with a mixture of dimethoxymethane-methanol (4 + 1) to further precipitate proteins, evaporation of dimethoxymethane followed by a liquid-liquid defatting with hexane and heating of the methanol-water mixture before the transfer of aflatoxins into chloroform. Chloroform extracts are further purified by silica gel—acidic alumina—anhydrous sodium sulfate column chromatography.