Oxidative stability of edible argan oil: A two-year study

The present study investigated the oxidative stability of the threemarketed types of edible argan oil. Edible argan oil is prepared by pressing the slightly roasted kernels of peeled argan fruit. High quality edible argan oil is exclusively prepared using mechanical presses. However, hand-extracted argan oil is still artisanally produced and can be found in local markets. In this latter case, goat-peeled fruit is still sometimes introduced in the oil production chain even though the resulting oil is notoriously of unsatisfactory quality. The oxidative stability of press-extracted, hand-extracted, and goat-peeled fruit derived argan oil was analyzed using as physicochemical metrics: fatty acid composition, β-carotene level, phosphorus level, tocopherol level, iodine index, saponification, peroxide and acid values, specific extinction, and Rancimat induction time. The variations of these parameters were evaluated over a period of 2 years at 5 °C, 25 °C (protected or exposed to sunlight), or 40 °C. After this period of time, mechanically extracted argan oil still presents an excellent physicochemical profile. Domestic and traditionally prepared argan oil presents much less satisfactory properties after the same period.     

Shape, sizing optimization and material selection based on mixed variables and genetic algorithm

In this work, we explore simultaneous designs of materials selection and structural optimization. As the material selection turns out to be a discrete process that finds the optimal distribution of materials over the design domain, it cannot be performed with common gradient-based optimization methods. In this paper, material selection is considered together with the shape and sizing optimization in a framework of multiobjective optimization of tracking the Pareto curve. The idea of mixed variables is often introduced in the case of mono-objective optimization. However, in the case of multi-objective optimization, we still face some hard key points related to the convexity and the continuity of the Pareto domain, which underline the originality of this work. In addition to the above aspect, there is a lack in the literature concerning the industrial applications that consider the mixed parameters. Continuous variables refer to structural parameters such as thickness, diameter and spring elastic constants while material ID is defined as binary design variable for each material. Both mechanical and thermal loads are considered in this work with the aim of minimizing the maximum stress and structural weight simultaneously. The efficiency of the design procedure is demonstrated through various numerical examples.     

Polymerizations of hexamethylcyclosiloxane catalyzed by metal sulfonate/acid chloride combinations

Hexamethylcyclotrisiloxane (D₃) was polymerized in bulk at 100°C, and the conversion was monitored by ¹H‐NMR spectroscopy. Various metal triflates, which were inactive as neat salts, were combined with chlorosilanes, chlorostannanes, phenyl phosphonyl chloride, and carboxylic acid chlorides, which were also inactive when added alone. Most 1 : 1 combinations proved to produce active catalysts for the ring‐opening polymerization of D₃. When the anions of sodium salts were varied alkylsulfonates and the sulfates were more reactive than the triflate. The samarium triflate/diphenyldichlorosilane combination was found to be the most reactive catalyst on the basis of the triflate ions. Regardless of the catalyst combination, the main reaction products in the early stages of all polymerizations were octamethylcyclotetrasiloxane (D₄) and decamethylcyclopentasiloxane (D₅). The polymerization mechanism is discussed. The reactive catalyst combinations also polymerized D₄ at 100°C. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Ionic liquid modified zinc oxide injection layer for inverted organic light-emitting diodes

We have demonstrated a novel approach for fabricating efficient hybrid organic–inorganic light emitting diodes (HyLEDs) by introducing dopants into solutions processable metal oxides as an interfacial layer. The doped ZnO is prepared by adding ionic liquid (IL) to a precursor solution for the ZnO. In this way a heavily doped ZnO:ILs cathode was obtained that enhances the electron injection properties and assures a good wetting of the organic active materials.     

Recent Advances in Copper-Based Solid Heterogeneous Catalysts for Azide–Alkyne Cycloaddition Reactions

The copper(I)-catalyzed azide−alkyne cycloaddition (CuAAC) reaction is considered to be the most representative ligation process within the context of the “click chemistry” concept. This CuAAC reaction, which yields compounds containing a 1,2,3-triazole core, has become relevant in the construction of biologically complex systems, bioconjugation strategies, and supramolecular and material sciences. Although many CuAAC reactions are performed under homogenous conditions, heterogenous copper-based catalytic systems are gaining exponential interest, relying on the easy removal, recovery, and reusability of catalytically copper species. The present review covers the most recently developed copper-containing heterogenous solid catalytic systems that use solid inorganic/organic hybrid supports, and which have been used in promoting CuAAC reactions. Due to the demand for 1,2,3-triazoles as non-classical bioisosteres and as framework-based drugs, the CuAAC reaction promoted by solid heterogenous catalysts has greatly improved the recovery and removal of copper species, usually by simple filtration. In so doing, the solving of the toxicity issue regarding copper particles in compounds of biological interest has been achieved. This protocol is also expected to produce a practical chemical process for accessing such compounds on an industrial scale.     

Reply to Comment on "Synthesis of ZnS thin films using the spray pyrolysis technique"

Journal of Materials Science: Materials in Electronics -     

An energy and memory-efficient distributed self-reconfiguration for modular sensor/robot networks

Self-reconfiguration for mobile microrobots currently needs a positioning system and a map of the target shape. Traditional positioning solutions, such as GPS or multilateration are not applicable in the micro-world, and maps sharing does not scale. In the literature, if we want a self-reconfiguration of microrobots to a target shape that consists of millions of positions, each microrobot should have a memory capacity of at least million positions. Therefore, this is not scalable. In this paper, nodes do not record any position. We present self-reconfiguration methods where nodes are unaware of their positions and where they do not have the final coordinates of each microrobot. In other words, nodes do not store the coordinates that build the target shape. Therefore, memory usage for each node is hugely reduced to \(O(1)\) and communications are limited to neighboring nodes. These algorithms aim to improve the logical topology of a set of microrobots by restructuring their physical topology. To that end, we consider here the case of restructuring a set of microrobots from a chain to a square and we study two algorithms: the first algorithm ensures the connectivity of the network at the end of the algorithm, where the second guarantees the connectivity of the network through the execution time. The paper presents both analytical and experimental assessments of the algorithms performances using the declarative language \(Meld\) and executed under the Dynamic Physical Rendering Simulator (DPRSim).     

Planar dual-band 27/39 GHz millimeter-wave MIMO antenna for 5G applications

Microsystem Technologies - This research work presents another design of a multi-input multi-output (MIMO) antenna with dual wide operating bands at the millimeter-wave (MMW) region proposed for 5G...