Elimination of polyphenols toxicity from olive mill wastewater sludge by its co-composting with sesame bark

Olive mill wastes represent a significant environmental problem in Mediterranean areas where they are generated in huge quantities in a short period of time. Their high phenol, lipid and organic acid concentrations turn them into phytotoxic materials, but these wastes also contain valuable resources such as a large proportion of organic matter and a wide range of nutrients that could be recycled. Composting is one of the technologies used for the valorization of this effluent, producing a fertilizer useful for poor soils.The present work deals with the changes that occur in the content of phenolic compounds and the biotoxicity of the oxidized substrate which result from the composting of olive mill wastewater (OMW) sludge with sesame bark. The total organic matter decreased 52.72% while water-soluble phenol degradation decreased 72% after 7 months of processing. Gas chromatography coupled with mass spectroscopy was used to confirm the elimination of polyphenols during composting. Initially, the analysis showed three abundant polyphenolic compounds, one of which was identified as the 4-hydroxyphenyl-ethanol (tyrosol), a well-known antioxidant in OMW. After 7 months of composting, all of the phenolic compounds disappeared. The phytotoxic effects of OMW sludge, assessed by the plant index germination, increased during the composting to reach 80% after 210 days. This trend was confirmed by the correlation between physico-chemical and toxicity parameters. The results obtained confirmed the stability of the compost prepared from OMW sludge with sesame bark and indicated a gradual detoxification as the compost matured.     

Biological activity during co-composting of sludge issued from the OMW evaporation ponds with poultry manure-Physico-chemical characterization of the processed organic matter

Olive mill sludge (OMS), a by-product resulting from natural evaporation of olive oil processing effluent, poses a major environmental threat. A current cost-effective practice of OMS management is composting. A mixture of OMS (60%) with poultry manure (PM) was successfully composted for 210 days. During the process, effluents of olive oil mill and confectionary were used to keep moisture at optimal level (40-60%). Biological indicators reflecting stability of the compost (microbial biota respiration and enumeration, and germination index) were analysed for the assessment of the product quality. The composted mixture showed a high microbial activity with a succession of microbial populations depending on the temperature reached during the biodegradation. The pathogen content from PM decreased with composting as did phytotoxic compounds. Phenols and lipids were reduced, respectively, by 40% and 84% while germination index increased with composting progress. Fourier transform infrared (FTIR) spectroscopic analysis revealed that the final compost improved the aromatic content compared to the starting materials, with a decrease in aliphatic groups and a reduction in the easily assimilated components by the microflora acting during the biological process. The final compost was characterized by relatively high organic matter content (26.21%), a low C/N ratio (16.21), an alkaline pH (8.32), a relatively high electrical conductivity (9.21mS/cm) and a high level of nutrients. The germination index for Lepidium sativum L. was 87.71% after 210 days of composting, showing that the final compost was not phytotoxic.     

Comparison between Lemaitre and Gurson damage models in crack growth simulation during blanking process

In this paper, the numerical results obtained by a finite element analysis in the case of sheet metal blanking process are compared with the experimental ones to verify the validity of Gurson and Lemaitre damage models in describing the initiation and propagation of cracks during the process evolution. The concept of continuum damage mechanics has been retained to describe the progressive damage accumulation into the sheet metal leading to the final rupture. During the analysis, the crack propagation is simulated by the propagation of a completely damaged area. The comparative study of the results obtained by simulations using different damage models and experimental ones, showed that Gurson damage model is not able to predict the fracture propagation path in a realistic way. Only Lemaître damage model gives good results.     

Aflatoxin determination in commonly consumed foods in Tunisia

BACKGROUND: To investigate natural aflatoxin occurrence, a total of 180 samples of different foods widely consumed in Tunisia were analysed by an in‐house‐validated high‐performance liquid chromatography method including affinity column clean‐up and post‐column bromination techniques. RESULTS: The method used appeared to be rapid, selective and reproducible, and its performances were established. Detection limits were 0.05 ng g^?1 for aflatoxin B1 and 0.025 ng g^?1 for aflatoxins B2, G1 and G2. Aflatoxins were detected in all investigated commodities except rice, with an overall contamination frequency of 34.4% and concentrations ranging from 0.1 to 40.6 ng g^?1. Aflatoxin B1 was found in all contaminated samples. Sorghum, spices and nuts were most contaminated. CONCLUSION: This study has provided an effective analytical method for the reliable determination of aflatoxins in food samples. Over one‐third of the samples investigated were contaminated with aflatoxins. Sorghum, spices and nuts were most contaminated, whereas rice showed no contamination. Copyright © 2010 Society of Chemical Industry     

A Joint Use of Both PAPR Reduction and Neural Network Predistortion Approaches to Compensate the HPA Non-Linearity Impact on FBMC/OQAM Signals

Filter Bank Multi-carrier Modulations with Offset Quadrature Amplitude Modulations (FBMC/OQAM) is an appropriate alternative to Orthogonal Frequency Division Multiplexing (OFDM) for the fifth generation radio access technology. Being a multi-carrier modulation scheme (MCM), FBMC/OQAM suffers from high Peak to Average Power Ratio (PAPR) and thus exhibits significant distortion in the presence of a non-linear high power amplifier (HPA). To date, no research has considered the idea of combining both linearization and PAPR reduction approaches for the FBMC/OQAM system to cope with this problem. In this paper we jointly used the Tone Reservation (TR) PAPR reduction scheme and the Neural Networks Predistortion (NNPD) as a linearization scheme for both the FBMC/OQAM and the OFDM systems. We suggest a serial combination of the TR and the NNPD schemes. Numerical results showed that the proposed combination of the TR and the NNPD schemes provided better performances than when used separately for both OFDM and FBMC/OQAM systems.     

Feedback behavior and its role in trust assessment for peer-to-peer systems

One of the significant characteristics of ubiquitous environments is the need for trust management due to the vital role trust plays in the success of such environments. Recommenders constitute an important component for managing trust because they can corrupt the recommendation network by providing bogus feedback resulting in losing transactions with trustworthy nodes and committing transactions with untrustworthy nodes. Honesty checking schemes, assume that a recommender is consistent and thus does not change its recommendation behavior. In this paper, we shed light on the inconsistent recommenders’ behavior. That is, recommenders change their recommendation strategy. To the best of our knowledge, this is the first attempt at linking the behavior change to honesty checking. We propose a new honesty checking algorithm and show through extensive simulation experiments its performance compared to existing honesty checking algorithms.     

Mobile Localization Under Non-Line-of-Sight Conditions Using Scattering Information

A novel mobile localization algorithm under non-line-of-sight (NLoS) conditions involving at most two base stations (BS) is presented. By using such a small number of BSs, the proposed technique avoids problems related to weak mobile hearability and excessive network messaging overload. Based on a scattering model, the NLoS hybrid approximate maximum likelihood (NLoS HAML) approach presented herein estimates the distances between the mobile station (MS) and the scatterers through the measured hybrid time-of-arrival/angle-of-arrival (ToA/AoA) statistics. Then, it matches the calculated distances to a known scatterers’ distribution in a maximum likelihood (ML) sense. Numerical results prove that the proposed algorithm outperforms previous methods by providing an accuracy enhancement that reaches 60%. It is also shown that the performance enhancement provided by the proposed algorithm is maximized when the adequate scatterers distribution is adopted.     

Preparation,Infra-red,MAS-NMR and Structural Characterization of a New Copper Based Inorganic–Organic Hybrid Compound: [C<Subscript>5</Subscript>H<Subscript>6</Subscript>N<Subscript>2</Subscript>Cl]<Subscript>2</Subscript>CuCl<Subscript>4</Subscript>

The ionic salt [2(C₅H₆N₂Cl)⁺], [CuCl₄]^2? complex of copper(II) has been synthesized and characterized. The X-ray diffraction analysis with a single crystal of this compound showed that the title compound (4-amino-2-chloropyridinium)₂CuCl₄ [(CAP)₂CuCl₄], crystallized at room temperature in the monoclinic system, space group C_2/c (N°.15) and the following : a = 16.0064 (2) Å; b = 7.7964 (10) Å; c = 14.7240 (2) Å; β = 102.497 (10)°; V = 1793.91 (4) ų and Z = 4. The structure was solved by using 1,589 independent reflections down to R value of 0.021. The unit cell is made up of tetrachlorocuprate(II) anions and 4-amino-2-chloropyridinium cations linked together by an extensive hydrogen bond network of types N–H···Cl (N: pyridinium) and N–H···Cl (N: amine), and cation-lone pair of nitrogen element interactions. Solid state NMR spectra showed one and five isotropic resonances, ⁶³Cu and ¹³C, respectively, confirming the solid state structure determined by X-ray diffraction. Impedance spectroscopy study, reported for single crystal, revealed that the conduction in the material was due to a hopping process. This work aims to reveal the thermal properties of a new copper(II) based organic–inorganic hybrid and the conductivity properties that these compounds exhibit.     

The Capacity Performance of ASTC-MIMO-OFDM System in a Correlated Rayleigh Frequency-Selective Channel

Algebraic Space-Time Codes (ASTC) for Multiple Input Multiple Output (MIMO) systems are based on quaternion algebras. Thanks to their algebraic construction, the ASTC codes are full-rank, full-rate and have the non-vanishing determinant property. These codes have been proposed for MIMO flat fading channels in order to increase the spectral efficiency and to maximize the coding gain. The purpose of this work is to analyze the performance of the ASTC in a frequency selective Rayleigh channel. To deal with the frequency selectivity, we use the OFDM modulation. The capacity performances of an ASTC-MIMO-OFDM system, under correlated Rayleigh frequency-selective channel, have been evaluated.