Characterisation of the glycerophospholipid fraction in flaxseed oil using liquid chromatography–mass spectrometry

A high-performance liquid chromatographic method coupled with mass spectrometry was used to characterise the natural phospholipid (PL) classes and molecular species in flaxseed oils. The PL fraction included phosphatidylethanolamine (PE) (27–40%), phosphatidylinositol (PI) (29–32%), phosphatidylcholine (PC) (7–18%), lysophosphatidylcholine (LPC) (8–21%), phosphatidylglycerol (PG) (1–4%) and phosphatidic acid (PA) (1–9%). The distribution of fatty acids was found to differ between phospholipids. Stearic acid was mainly present in the form of PC and LPC. Palmitic acid was present in the most abundant molecular species in PI, PG and PA whereas linoleic acid formed the most abundant molecular species in PE.     

Compatibilization of PE/PS and PE/PP blends. I. Effect of processing conditions and formulation

The objective of this work was to study the effectiveness of low‐cost commercial compatibilizers and several processes (internal mixer, single‐ and twin‐screw extruders) for two types of plastic blends: high‐density polyethylene/polypropylene and high‐density polyethylene/polystyrene blends, to gain insight into the recycling of wastes from those frequently encountered mixed plastics. Blends going from a pure A to a pure B component, with and without a compatibilizer, were prepared using an internal mixer, a corotating twin‐screw extruder, as well as a single‐screw extruder to follow an industrial‐convenient process. In both cases, the analyses of blend morphologies highlighted the poor adherence between the two phases in the uncompatibilized blends. Compatibilized blends display better adherence between phases and the ability to process blends made from both single‐ and twin‐screw extruders. When adding a compatibilizer, the viscosity of each blend (PE/PP or PE/PS) increased due to a better adhesion of the phases. Charpy impact tests showed that the presence of the compatibilizer in PE/PS blends increased their impact properties. Indeed, the improvement of the adhesion between the two phases enabled stress transfer at the interface. A single‐screw extruder seems to be efficient as a processing method on an industrial scale when a compatibilizer is used. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2475–2484, 2003     

Screening and Profiling of Hydrocarbon Components and Squalene in Developing Tunisian Cultivars and Wild Arachis hypogaea L. Species

Total hydrocarbon composition and content of whole peanuts from three Tunisian varieties of peanut (two cultivars: AraC (Virginia type), AraT (Valencia type) and a wild one: AraA) were investigated during maturation. The results show that 30 hydrocarbons were identified from the wild AraA species, while only 27 hydrocarbon were detected in the cultivar ones. The hydrocarbon fraction is essentially composed of squalene, n-alkenes especially nC₁₄₌, nC₁₆₌, nC₁₈₌, nC₂₀₌ and nC₂₂₌, n-alkanes such as nC₁₆, nC₁₇, nC₁₈, nC₂₅, nC₂₆ and nC₂₇, and branched saturated hydrocarbon noted (HC₁, HC₂ and HC₃). Among the hydrocarbon components, generally the wild variety AraA presents the highest content of phytochemical squalene during maturation, whereas a maximum was detected from cultivar AraT at 12 days after podding (815.45 mg/100 g of oil). At maturity, the maximum level is reached at about 346.74 mg/100 g of oil for AraA. During maturity, wild AraA is considered to be an excellent source of squalene like olive and pumpkin oil.     

Growth and physical properties of in situ phosphorus-doped RTLPCVD polycrystalline silicon thin films

In situ phosphorus-doped (P-doped) polysilicon (poly-Si) thin films are obtained by rapid thermal low pressure chemical vapor deposition (RTLPCVD) in a single chamber RTP machine by using diluted silane (SiH₄/Ar=10%) and phosphine (PH₃=200 ppm). Deposition kinetics of poly-Si films were studied in the 600–850°C temperature range at fixed total pressure of 2 mbar and gas flow rate (100 sccm). Activation energy of 1.82 eV was calculated in the surface reaction deposition regime. Dopant activation has been obtained sequentially by RTO at 1000°C in pure O₂ atmosphere. This later process permits to both activate the phosphorus dopant and forms an ultrathin polyoxide which blocks dopant outdiffusion. Secondary ion-mass spectrometry (SIMS) analysis showed flat P-dopant profiles throughout the film thickness with a P concentration varying from 5.5×10²⁰ to 2.4×10¹⁹ at/cm³ when the deposition temperature increases in the 600–850°C range. Grazing incidence X-ray diffraction (XRD) has been used to study the structural properties of the poly-Si layers. It appeared particularly that the amorphous to crystalline temperature transition occurs at around 650°C. Finally, four-point probe measurements showed that sheet resitivities in the mΩ cm range can be routinely achieved for in situ P-doped RTLPCVD poly-Si films.     

Changes in the Content of Phenolic Compounds in Flaxseed Oil During Development

The phenolic fraction of flaxseed oil was quantified during the development of three varieties (H52, O116 and P129). Seed samples were collected at regular intervals from 7 to 56 days after flowering (DAF). During oilseed processing, less polar compounds are co-extracted with oil. The methanolic extracts were obtained by solid phase extraction. Separation of phenolic compounds was conducted by high-performance liquid chromatography-mass spectrometry. The main phenolic compounds detected during maturation were: diphyllin, pinoresinol, matairesinol, secoisolariciresinol, vanillic acid, ferulic acid and vanillin. The highest amount of lignans (6.74 mg of analyte/kg of flaxseed oil) was detected at 7 DAF in P129 variety. The maximum level of phenolic acids (2.57 mg of analyte/kg of flaxseed oil) was reached at 7 DAF in P129 which had also the highest content of simple phenols (1.37 mg of analyte/kg of flaxseed oil) at the same date after flowering. At full maturity, the content of phenolic compounds in three varieties ranged from 0.26 to 0.36 mg of analyte/kg of flaxseed oil. The highest content of total phenolic compounds using the Folin–Ciocalteu method was detected in P129 variety (196.42 mg CAEs/kg of flaxseed oil) at 7 DAF. Results of this study indicate that flaxseed oils contain different amounts of phenolic compounds using different methods.     

Experimental study on dielectric relaxation in alfa fiber reinforced epoxy composites

Investigation on dielectric properties and behavior of thermoset epoxy composite based on cellulosic fibers has been carried on. Dielectric spectra were measured in the frequency range 0.1 Hz–100 kHz and at temperature intervals from ambient to 200°C. For the composite, four relaxations processes were identified, namely the orientation polarization imputed to the presence of polar water molecules in Alfa fiber, the α mode relaxation associated with the glass transition of the epoxy resin matrix, the relaxation process associated with conductivity occurring as a result the carriers charges diffusion noted for high temperature above glass transition and low frequencies, and interfacial or Maxwell‐Wagner‐Sillars relaxation that is attributable to the accumulation of charges at the Alfa fibers/epoxy resin interfaces. Dielectric relaxation analysis revealed evolution in water relaxation and it is thus concluded that the chemical treatment of the fiber can strongly influence the dielectrical properties and interfacial polarization processes in composites. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

Sequential decoding with ARQ and code combining: a robust hybridFEC/ARQ system

Sequential decoding with ARQ (automatic-repeat-request) and code combining under the timeout condition is considered. That is, whenever the decoding time of a given packet exceeds some predetermined duration, decoding is stopped and retransmission of the packet is requested. However, the unsuccessful packets are not discarded, but are combined with their retransmitted copies. It is shown that the use of code combining allows sequential decoding to operate efficiently even when the coding rate R exceeds the computational cutoff rate R _comp. Furthermore, an analysis of the selective-repeat ARQ scheme shows that the use of code combining yields a significant throughput even at very high channel error rates, thus making the system very robust under severe degradations of the channel     

An efficient convolutional coding/decoding strategy for channelswith memory

Many digital communication channels are affected by errors that tend to occur in bursts. A great deal of work has been devoted to finding good burst-error-correcting codes and developing burst-error-correcting schemes. However, burst-error-correcting codes are generally not effective for long bursts. Some burst-error-correcting schemes suffer long delay in decoding. Others are very sensitive to random errors in the guard space. Most of these schemes are not adaptive to channel conditions. A new adaptive scheme is proposed to overcome these drawbacks. The scheme employs a combination of two complementary punctured convolutional (CPC) codes. One of the codes is used for burst detection and for channel state estimation, and both codes are used for error correction. The proposed scheme is analyzed over a two state Markov chain channel model. Unlike existing burst-error-correcting schemes, it is shown that the proposed scheme is adaptive to channel conditions and less sensitive to errors in the guard space. For the same delay, the proposed scheme offers better performance than the interleaving schemes. When the channel is heavily corrupted by bursts, the improvement is even more pronounced     

Policosanol characterization and accumulation during ripening of Tunisian Olea europaea L. fruits

Policosanol is a mixture of bioactive molecules shown to have beneficial effects in treating hypercholesterolemia. Food products enriched in policosanol are currently available in the US market. In the present study, eight policosanol components were identified by GC‐MS during the ripening of Meski olives. The quantitative characterization of these compounds was performed using GC‐FID. The results showed that the maximum level of total policosanol components (947.20 mg/100 g oil) was reached at the 26^th week after the flowering date of Meski olives. Hexacosanol and tetracosanol were the predominant policosanol components at Meski olive maturity. However pentacosanol, heptacosanol and tricosanol were less present in the olives and they accounted for 14% of the total policosanol at complete maturity of the fruit. The total policosanol content of Meski olives was higher than that of beeswax and whole sugar cane, which belong to the sources of dietary supplements containing policosanol. These findings indicate that olive is a potential source of these health‐enhancing compounds for functional foods and nutraceutical applications.     

IoT‐fog‐cloud based architecture for smart systems: Prototypes of autism and COVID‐19 monitoring systems

Making resources closer to the user might facilitate the integration of new technologies such as edge, fog, cloud computing, and big data. However, this brings many challenges shall be overridden when distributing a real‐time stream processing, executing multiapplication in a safe multitenant environment, and orchestrating and managing the services and resources into a hybrid fog/cloud federation. In this article, first, we propose a business process model and notation (BPMN) extension to enable the Internet of Things (IoT)‐aware business process (BP) modeling. The proposed extension takes into consideration the heterogeneous IoT and non‐IoT resources, resource capacities, quality of service constraints, and so forth. Second, we present a new IoT‐fog‐cloud based architecture, which (i) supports the distributed inter and intralayer communication as well as the real‐time stream processing in order to treat immediately IoT data and improve the entire system reliability, (ii) enables the multiapplication execution within a multitenancy architecture using the single sign‐on technique to guarantee the data integrity within a multitenancy environment, and (iii) relies on the orchestration and federation management services for deploying BP into the appropriate fog and/or cloud resources. Third, we model, by using the proposed BPMN 2.0 extension, smart autistic child and coronavirus disease 2019 monitoring systems. Then we propose the prototypes for these two smart systems in order to carry out a set of extensive experiments illustrating the efficiency and effectiveness of our work.