Optimization of Corynebacterium glutamicum Glutamic Acid Production by Response Surface Methodology

Response surface methodology (RSM) was used to evaluate the effects of fermentation parameters for glutamic acid (GA) production by Corynebacterium glutamicum CECT690 in submerged fermentation using palm date waste as substrate. To attain this purpose at the first stage, inoculum size, substrate concentration, penicillin concentration, phosphate concentration, and inoculum age were optimized for GA production. The next stage, the level of air flow rate in a 5-l fermenter (batch mode) which was run in optimized conditions was determined. The first stage gave the following results for the fermentation conditions optimized using RSM in 500-ml shake flasks: inoculum size 2% (v/v), substrate concentration 25% (w/v), penicillin concentration 1 U/ml, phosphate concentration 4 g/l, and inoculum age 10 h. Moreover, the maximum GA amount predicted by the model was 39.32 mg/ml. This was in agreement with the actual experimental value (36.64 mg/ml). In the second stage of the study, the amounts of GA were 118.75, 142.25, and 95.83 mg/ml in optimized conditions with the three levels of air flow rate of 0.6, 1.2, and 1.6 vvm, respectively. The present results demonstrate the potential of date waste juice as a substrate for producing GA by cultivation of C. glutamicum.     

Phase-Field Modeling of Eutectic Growth in a Ti-Fe System with Multiple Nuclei and Misorientations

In this article a phase-field model to investigate the formation of eutectic structures in a Ti-Fe alloy with high elastic misfit is introduced. Based on linear microelasticity theory, an elastic model is designed to incorporate the elastic energy into the phase-field formalism and later on adopted to growth of multiple nuclei with arbitrary orientations by including the orientation energy in phase-field ansatz. By using this model, we investigate the free growth of a limited number of eutectic nuclei and examine the influence of orientation free energies on elastic fields and the resulting microstructure.     

Effect of mechanical activation on thermal energy storage properties of Co3O4/CoO system

The heat produced by a solar receiver during on-sun operation can be employed to drive the endothermic reduction reaction of Co₃O₄ to CoO; then the consumed thermal energy can be recovered completely by the exothermic reverse oxidation reaction of CoO to Co₃O₄ which can take place during off-sun operation. In this research, the effect of mechanical activation duration (1, 2, 4, 8, and 16?h) on thermal energy storage by Co₃O₄/CoO redox pair was investigated. It was found that increasing the mechanical activation duration increases the sintering and particle size of the cobalt oxide powder after one cycle redox, and subsequently the thermal energy storage properties are declined. The weight loss was about 4–5?wt.% for samples heated by 1, 3, and 5?$°\text{C}$/min, while it was about 2?wt.% for 10?$°\text{C}$/min heating rate and less than 1?wt.% for 15?$°\text{C}$/min heating rate. The comparison of cycleability of as-received and 1?h mechanical activated cobalt oxide showed that mechanical activation weakens the cycleability of redox reactions of cobalt oxide. The as-received cobalt oxide cycleability continued up to three cycles, although the reduction and oxidation capacities gradually declined. The cycleability of 1?h mechanical activated sample entirely diminished after two cycles.     

Evaluation of excitation function by TALYS code for producing ^109Cd with different ion beams

ion of millicurries of the radioisotope with incident beam energy less 15 MeV using low energy accelerator.     

Magnetoelectric Effect in Ba0.5Sr0.5TiO3/CoFe2O4 Thin Film Prepared by Pulsed Laser Deposition Method

Magnetoelectric materials have attracted considerable attention for several decades owing to their both magnetic and electric properties. The magnetoelectric multilayer, Ba_0.5Sr_0.5TiO₃/CoFe₂O₄, has been fabricated by the aid of pulsed laser deposition technique and after fabrication characterized by X-ray diffraction pattern and magnetoelectric effect. Sufficient magnetoelectric coefficient has been observed in samples with increasing biased magnetic field. Our results suggest that magnetoelectric coupling effect may be tuned by interlayer properties and biased magnetic field which show the capability of use in nonvolatile memory, phase shifter, and sensor applications.     

Na2S-mediated thionation: an efficient access to secondary and tertiary α-ketothioamides via Willgerodt–Kindler reaction of readily available arylglyoxals with amines

The task of this paper is to provide an efficient process for synthesis of secondary and tertiary α-ketothioamides via Willgerodt–Kindler reaction of readily available arylglyoxals with amines using Na₂S as an effective catalyst. A plausible role for Na₂S in the reaction of arylglyoxals with primary amines is proposed.     

Micromorphology and Optical Bandgap Characterization of Copper Oxide Nanowires

Due to the industrial applications of nasno materials, the growth of Copper oxide (CuO) nanowires (NWs) at the same and opposite directions of the electric and gravitational fields was investigated to study the effects of fields on the NWs properties. The experiments were designed to grow NWs using thermal oxidation method at 450 ^°C for 50 h. NWs growth was evaluated to study two distinct cases; first, substrates exposed to the gravitational field and second those treated with electric field (EF) in-lined with gravitation field (GF). It was observed that the electric field developed a diameter homogeneity while compressing the NWs and decreasing the diameters. Furthermore, the GF influenced only the length of the NWs, while the EF had an impact on both length and diameter of the NWs. The direction of fields played an important role in NWs morphology and intensity of XRD pattern and optical properties. It was also observed that field direction greatly influenced the NWs length and diameter.     

Modelling of sintering during rotational moulding of the thermoplastic polymers

This paper concerns the study of sintering phenomenon during rotational molding of polypropylene(PP),Polyvinylidenefluoride (PVDF) and Polymethyl methacrylate (PMMA). First, the coalescence (first step of sintering) of two grains has been followed. Bellehumeur’s model has been tested as a model to explain this phenomenon. In order to study the effect of neighboring grains on coalescence of two grains, a third grain has been put in contact with these two grains. For modeling the phenomenon in this case, Bellehumeur’s model has been modified by a geometric parameter called Farz Factor (FF), being this model validated by experimental test. Concerning densification, two different stages have been observed. In the first stage, before welding of the grains and formation of interphases between them, the grains are not stuck yet. The air trapped between the grains escapes through free ways between grains. This first step of densification is directly related to the coalescence where the density of the polymer varies very quickly. A new tridimensional model, based on a Body Centered Tetragonal (BCT) configuration, has been proposed to explain the densification during this first stage. In the second stage, the migration of air is controlled by diffusion.