On-Board Hydrogen Production Through Catalytic Exhaust-Gas Reforming of Isooctane: Efficiency of Mixed Oxide Catalysts Ce2Zr1.5Me0.5O8 (Me = Co, Rh, or Co–Noble Metal)

Isooctane reforming under conditions which are set by exhaust gas can be built on to generate hydrogen on-board. Isooctane reforming reactivity tests have been performed with bimetallic catalysts Co–Noble Metal/ceria–zirconia. Variable activity of noble metals doped catalysts, depending on the nature of the noble metal, its loading, and affected by the activation process, is discussed.     

Optimization of Interface Conditions in the Case of Laser Diode Ignition of Pyrotechnic Mixtures

Ignition, by laser diode, of explosive reactions on pyrotechnical mixtures is presented in this paper. A model was studied in order to determine the ignition threshold energy of the pyrotechnic compositions. It results in a numerical solution of the heat equation, in transient, with a source term due to the in‐depth absorption of the laser radiation. The chemical reaction is modelled by the way of a kinetic law based upon an Arrhenius law. In order to take into account this interface phenomenon, a thermal resistance R_c of contact was introduced at the interface sapphire windows‐pellet. In this article, we propose to optimize this term and the depth μ of absorption of the laser radiation, in order to minimize the deviation from the experimental results. We thus obtain the value of R_c and of μ. While varying various parameters (density of power, porosity, percentage of carbon black), the adequacy of calculations and the experimental results will be highlighted. Based on the results obtained we show in Fe/KClO₄ mixture that the energy threshold is controlled more particularly by the conditions of the interface represented by the thermal resistance of contact R_c and coefficient of absorption μ.     

High Metal Chelating Properties from Rapeseed Meal Proteins to Counteract Lipid Oxidation in Foods: Controlled Proteolysis and Characterization

Rapeseed meal proteins (RP) are enzymatically hydrolyzed using three individual proteases (Alcalase, Flavourzyme, and Prolyve) and the enzymatic mechanism is studied. Rapeseed hydrolysates are produced under controlled conditions and the Prolyve hydrolysate is separated by membrane filtration. Their capacity to reduce free radicals (by transfer of hydrogen or electron) or transition metals (by electron transfer) in the absence of an oxidizable substrate, their metal chelating capacity as well as the antioxidant performances in model (conjugated autoxidizable triene assay) are investigated. All hydrolysates show a reduction capacity (by transfer of hydrogen or electron) and antioxidant activities, in a dose-dependent manner, which are however not significantly increased in comparison to the native proteins. A noteworthy metal chelating activity of the peptides produced with Prolyve is highlighted. These results indicate the potential of valorization of RP as a source of high metal chelating peptides to counteract lipid oxidation in foods. Practical applications: Over the last decade, the antioxidative potential of peptides from plant biomass has been evidenced by much research. Considering the myriad of possible sources and the diversity of technology and means to obtain peptides from protein materials, it is reasonable to expect more applications. Concomitantly, preventing lipid oxidation, especially with the polyunsaturated fat-based products, is a major concern in sectors such as agri-food and cosmetic. Although the efficacy of synthetic antioxidants is recognized, both consumers and manufacturers are looking for more innovative, healthy, environmental-friendly processes and quality products. In this context, a controlled proteolysis of proteins from plant by-products can be used as a sustainable strategy to produce antioxidant peptides. Among them, new peptides released from rapeseed proteins with Prolyve can provide interesting metal chelators to counteract lipid oxidation in foods.     

Selection of Natural Extracts for their Antioxidant Capacity by Using a Combination of In Vitro Assays

Numerous different in vitro assays, labeled as “antioxidant assays,” are used intensively to predict the antioxidant capacity of phenolic compounds. Most of these methods give valuable information in terms of chemical reactivities but also present some weaknesses. It may be difficult to use them to predict antioxidant capacity in real conditions. Indeed, lipid oxidation is a complex reaction, with numerous paths and components, and antioxidant action can occur via a multitude of mechanisms, especially when different phases coexist in the lipid-based formulation. Yet, correctly combining selected in vitro methods to extract complementary information with respect to antioxidant behaviors would be much better and will help reducing the gap between prediction and efficacy in the finished product. Thus, we hereby propose a methodology to evaluate the antioxidant properties of 12 selected natural polyphenolic extracts based on the appropriate combination of in vitro assays. The scores obtained with the DPPH test, the measure of the chelation capacity, the evaluation of antioxidants efficiency in emulsions (CAT and VESICAT assays), or in bulk oils were submitted to a statistical treatment. This analysis allowed a ranking on their global antioxidant capacities and the creation of clusters depending on their mechanisms of action and the type of media where the tests were performed.     

A comparative study of lupeol extraction from a by-product of lupin processing by hydrophobic natural deep eutectic solvents and their precursor components

A series of hydrophobic natural deep eutectic solvents (HNADESs) have been employed to extract lupeol from lupin seed coat at 30 and 70°C. The extraction yields have been compared with those obtained with conventional organic solvents. In general, lupeol extraction yields (LEYs) obtained when using HNADES are somewhat smaller than those obtained if organic solvents are used. However, the nature of the HNADES mixtures as green solvents represents a superior performance in terms of sustainability of the extraction process. Additionally, an investigation has been carried out in order to compare the LEYs obtained when using the HNADES mixtures with those obtained if the isolated precursor compounds are employed at a temperature (70°C) where both HNADES and the corresponding precursor compounds are liquids. Surprisingly, LEYs for lupeol at 70°C were found to be, in some cases, slightly higher if the precursor compounds are used in comparison with the proper HNADES mixtures. It seems that the unique properties of the HNADES mixtures are not enough to perform better as extractants in comparison with the isolated precursor compounds at moderate temperatures, at least for the case of lupeol from lupin seed coat. Some hints are presented to explain these results. Practical Applications: The demand to use by-products, such as raw materials, to obtain potential bioactive compounds is gaining strong attention in the last years. The use of green solvents to extract these compounds is also envisaged to obtain substances in an environment-friendly way and with high sustainability for the economy and end-consumers. The main aim of this work is the extraction of lupeol from lupin seed coat by using on one side different hydrophobic natural deep eutectic solvent (HNADES) mixtures, and on the other side by using the precursor compounds of the mixtures, in order to evaluate the efficiency of these green extraction solvents in the recovery of bioactive compounds with health benefits from waste material. Our results show that lupeol can be extracted both with the HNADES mixtures and with their precursor components at moderate temperatures with similar efficiency. This work questions the need of using HNADES as clean extraction solvents as the precursor compounds have themselves interesting extracting capacities.     

Formation of a 40 A DC Current Arc During the Opening of Silver Contacts

The erosion of silver contacts due to break arcs with length proportional to time and of variable duration has been measured by weighing the contacts following 5000 openings at a constant current equal to 40 A.The experimental results show that,for arc durations shorter than 60 μs,the transfer of metal from the anode to the cathode occurs,but after passing this stage,when the two electrodes are separated by greater distances,each will display erosion.This is the result of the diffusion of material outside the space between the two electrodes.In order to interpret these results,we have applied a classical model of the physical phenomena occurring at the root of the arc.Analysis of the experimental results shows that for an arc duration of less than15 μs,no distinct cathode root is seen to exist,but beyond this,several spots appear gradually on the cathode for arc duration up to 50 μs,after which they merge into a single spot.The comparison between experiment results and theoretical interpretation is reasonable up to 60 μs.     

Critical Infrastructures under Threat: Learning from the Anthrax Scare

Conventional thinking in emergency and crisis management focuses on the application of codified procedures to unforeseen contingencies. Modern society's increased dependence on critical infrastructures and the emerging vulnerabilities of these large‐scale networks create challenges that are hard to meet with conventional tools of crisis management. This article discusses the inherent vulnerabilities and explores the requirements of effective preparation for escalatory network breakdowns.