Rheological quantification of molecular parameters: Application to a hydrogen bond forming blend

The component dynamics and molecular parameters were investigated for miscible poly(4‐vinyl phenol)/poly(ethylene oxide) (PVPh/PEO) blends. Global values of molecular weight between entanglements (M_e) were first estimated for the blends and were compared with existing athermal model predictions. Global interchain friction coefficients (ξ) of the blends were deduced from the zero‐shear viscosity. A maximum was observed at a composition of 20–30 wt % of PEO. Chain dimensions of this phase are estimated by using a relationship between the plateau modulus and a packing length (i.e., number of individual chains present in a given small volume of the melt). A slight increase in M_e is observed at low PEO weight fraction (before 0.20), followed by a sharp decrease in M_e values after this concentration. Values of ξ in PVPh/PEO blends show a maximum value at 20–30 wt % of PEO. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 1623–1630, 2004     

Methanol fuel processor and PEM fuel cell modeling for mobile application

The use of hydrocarbon fed fuel cell systems including a fuel processor can be an entry market for this emerging technology avoiding the problem of hydrogen infrastructure. This article presents a 1 kW low temperature PEM fuel cell system with fuel processor, the system is fueled by a mixture of methanol and water that is converted into hydrogen rich gas using a steam reformer. A complete system model including a fluidic fuel processor model containing evaporation, steam reformer, hydrogen filter, combustion, as well as a multi-domain fuel cell model is introduced. Experiments are performed with an IDATECH FCS1200™ fuel cell system. The results of modeling and experimentation show good results, namely with regard to fuel cell current and voltage as well as hydrogen production and pressure. The system is auto sufficient and shows an efficiency of 25.12%. The presented work is a step towards a complete system model, needed to develop a well adapted system control assuring optimized system efficiency.     

Evaluation of Zefreh Dolomite (Central Iran) for Production of Magnesium via the Pidgeon Process

This study evaluates the production of magnesium metal from the Zefreh dolomite ore of Central Iran using the Pidgeon process. The investigation consisted of mineralogical and chemical characterization of the dolomite ore, calcining, chemical characterization, LOI (loss on ignition) determination, reduction tests on the calcined dolomite (dolime), using Iranian (Semnan) ferrosilicon and mineralogical, and chemical characterization of the reactants and products. Calcining of dolomite samples was carried out at approximately 1400°C in order to remove CO₂, moisture, and other easily volatilized impurities. The dolime was then milled, along with ferrosilicon, thoroughly mixed, and briquetted. The briquettes were heated at 1125°C--1150°C and 500 Pa in a tube reactor for 10--12 hours to extract the magnesium. The ferrosilicon to dolime ratio was determined based on the chemical analyses of the two reactants, using as a guide, and Mintek's Pyrosim software package. Magnesium extraction varied with ferrosilicon addition and with the dolime used, and reach about 80% under optimal conditions. The levels of major impurities encountered in the magnesium crown were similar to those in the crude metal production.     

Glycerol citrate polyesters produced through heating without catalysis

The influence of various heating methods without catalysis to prepare polyesters from citric acid : glycerol blends were studied. In the presence of short-term microwave treatments, i.e., 60 s at 1200 W, blends of glycerol and citric acid invariably formed solid amorphous polyesters. Fourier transform infrared spectroscopy showed that citric acid and glycerol blends can form highly stable polymers composed of ester bonds. The glycerol citrate polyester polymers exhibited the least degradation in water, more in acid solutions (0.1–1.0M HCl), and the most deterioration in strong alkaline solutions (0.1–1.0M NaOH) after 72 h soakings. Polyesters of glycerol and citric acid were studied with differential scanning calorimetry and thermal gravimetric analysis. The polyesters were found to be thermally stable (up to 313°C). © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Chemical composition changes in four green olive cultivars during spontaneous fermentation

Changes in some physico-chemical characteristics (pH and free acidity) and chemical composition (sugars, total phenolic and flavonoid contents) of four olive cultivars during spontaneous fermentation in brine were investigated. The cultivars were typical of the Moroccan market: “Moroccan Picholine”, “Languedoc Picholine”, “Ascolana” and “Sevillana”. The physico-chemical changes of olives and brines during fermentation process were monitored. A similar pattern of pH was noticed for the “Moroccan Picholine”, “Languedoc Picholine” and “Ascolana” cultivars with a final pH ranging between 4.4 and 4.6. The profile of free acidity measured throughout fermentation period in brines was in agreement with the pH trend. The concentration of sugars, total phenolic and flavonoids contents in olives flesh and brines during fermentation is reported. The loss of flavonoids, sugars and total phenolic contents in the olive flesh by the end of fermentation process was up to 60%, 63% and 79% in “Languedoc Picholine”, “Sevillana” and “Moroccan Picholine”, respectively. The main phenols identified and quantified in the different brines at the end of brining process were hydroxytyrosol, tyrosol, (+)-catechin and quercetine. The highest total phenolic content and antioxidant activity were obtained in Moroccan Picholine brine after 71 days of fermentation.     

Physicochemical characterization of actinomycetes isolated from decayed cedar wood: contact angle measurement

Physicochemical characterization of microorganism is very important in a wide range of scientific and technological fields. In this study, we reported the isolation and the molecular identification of actinomycetes recovered from cedar wood decay. The isolates named H5 and H8 were identified by 16S rDNA sequencing and were shown to belong to the genus Nocardia and Streptomyces, respectively. Furthermore, physicochemical proprieties including hydrophobicity, electron donor/acceptor, and the Lifshitz–van der Waals (γ^LW) of these strains were evaluated using contact angle measurements. The results showed that Nocardia sp. (H5) had a hydrophobic (ΔGiwi?=??78.56?mJ/m²) and a weak electron donor/acceptor character. In contrast, results from contact angle measurements showed that the surface free energy of Streptomyces strains (H2, H3, and H8) were ΔGiwi?=?20.71?mJ/m², ΔGiwi?=?30.63?mJ/m², and ΔGiwi?=?15.35?mJ/m², respectively, classifying these microorganisms as hydrophilic bacterium. Moreover, the three strains were predominantly electron donating (γ^–?) and exhibit a weak electron-accepting (γ⁺) character.     

Preparation and characterization of highly stable monodisperse argan oil‐in‐water emulsions using microchannel emulsification

Argan oil is well known for its nutraceutical properties. Its specific fatty acid composition and antioxidant content contribute to the stability of the oil and to its dietetic and culinary values. There is an increasing interest to use argan oil in cosmetics, pharmaceutics, and food products. However, the formulation of highly stable emulsions with prolonged shelf life is needed. In this study, argan oil‐in‐water (O/W) emulsions were prepared using microchannel (MC) emulsification process, stabilized by different non‐ionic emulsifiers. The effects of processing temperature on droplet size and size distribution were studied. Physical stability of argan O/W emulsions was also investigated by accelerated stability testing and during storage at room temperature (25 ± 2°C). Highly monodisperse argan O/W emulsions were produced at temperatures up to 70°C. The obtained emulsions were physically stable for several months at room temperature. Furthermore, emulsifier type, concentration, and temperature were the major determinants influencing the droplet size and size distribution. The results indicated that a suitable emulsifier should be selected by experimentation, since the interfacial tension and hydrophilic–lipophilic balance values were not suitable to predict the emulsifying efficiency. Practical applications: MC emulsification produces efficiently monodisperse droplets at wide range of temperatures. The findings of this work may be of great interest for both scientific and industrial purposes since highly stable and monodisperse argan oil‐in‐water emulsions were produced which can be incorporated into food, cosmetic, or pharmaceutical formulations.     

Global Practical Mittag Leffler Stabilization by Output Feedback for a Class Of Nonlinear Fractional‐Order Systems

In this paper, the problem of a global practical Mittag Leffler feedback stabilization for a class of nonlinear fractional order systems by means of observer is described. The linear matrix inequality approach is used to guarantee the practical stability of the proposed feedback fractional order system. An illustrative example is given to show the applicability of the results.     

Optical properties of lithium titanate as a potential layer in light harvesters

Journal of Materials Science: Materials in Electronics - Various solar cell architectures and materials are currently studied, seeking enhanced photon management mechanisms. Herein, we provide an...     

Properties of Coated Controlled Release Diammonium Phosphate Fertilizers Prepared with the Use of Bio-based Amino Oil

In an effort to enhance the efficiency of fertilizer use and minimize their negative impact on the environment, a novel biomass-based, functional controlled-release fertilizer was used to improve nutrient use efficiency and increase crop production systems for more sustainable agriculture practices. Here, bio-based amino-oil (Priamine) mixtures were proposed as an outer coating with different layers for the control of phosphorus release from diammonium Phosphate (DAP). These hydrophobic coatings conferred excellent barrier properties and flexibility to coatings. The morphological characterization of the coated fertilizer was performed by scanning electronic microscopy (SEM), electronic diffraction X-ray (EDX) and mapping, and revealed the formation of a cohesive film and a good adhesion between DAP fertilizer and coating film. The release rate of nutrients (phosphate) in water was investigated by UV–Vis spectrophotometer. The effect of coating thickness was investigated on release time and diffusion coefficient of phosphor release in distilled water. Release time increased with the coating thickness. The diffusion coefficient of nutrient release decreased with the coating thickness. Compared with uncoated granule which is totally solubilized after less than 2 hours, the P release profiles of the coated granules reached the equilibrium stage approximately after 98 and 126 hours when the DAP is coated with only Priamine single-layer (1L) and double-layer (2L), respectively. Moreover, the strategy adopted has successfully provided a very slow release and long-term availability of nutrient sources with bio-based coating oil compared to uncoated fertilizer (DAP) and therefore exhibited promising application for sustainable development of modern agriculture and circular economic.