The use of biomass and stillage recycle in conventional ethanol fermentation

Modifications of the conventional ethanol fermentation process using biomass and stillage recycle were investigated and the advantages of the technique were studied. The biomass recycle method resulted in a reduction in the use of approximately 8% raw material (molasses). The recycle of 15–70% of stillage (dealcoholised) from a previous fermentation was also tested successfully. Generally the results of these experiments revealed 13–47% less water consumption and consequently about 13–47% reduction of stillage volume, which was more economical for further treatments.     

Thermal,mechanical, and corrosion resistance properties of vinyl ester/clay nanocomposites for the matrix of carbon fiber‐reinforced composites exposed to electron beam

Vinyl ester/clay nanocomposites with 1, 3, and 5% nanoclay contents were prepared. X‐ray diffractography patterns and Scanning Electron micrographs showed that nanocomposites with the exfoliated structure were formed. Thermogravimetric analysis, water absorption test, and Tafel polarization method, respectively, revealed the improvements in thermal resistance, water barrier properties, and corrosion resistance properties of the samples with an increase in the amount of the incorporated nanoclay. Tensile tests showed that nanoclay also enhanced the mechanical properties of the polymer, so that the tensile strength of the samples with 5% nanoclay was more than 3 times higher than tensile strength of pure vinyl ester samples. Overall, the best properties were observed for the samples containing 5% nanoclay. Pure vinyl ester and nanocomposite with 5% nanoclay content were exposed to the electron beam radiation and their mechanical properties improved up to 500 kGy irradiation dose. Finally, pure vinyl ester and vinyl ester/nanoclay (5%) matrixes were reinforced with carbon fiber and the effect of electron beam irradiation on their mechanical properties was examined. The tensile strength and the modulus of the samples initially increased after exposure to the radiation doses up to 500 kGy and then a decrease was observed as the irradiation dose rose to 1000 kGy. Moreover, nanoclay moderated the effect of the irradiation. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42393.     

Modeling and optimization of the chamber of OWC system

Due to their non-polluting nature and environment friendliness, Renewable Energies have gained great deal of attention and deserve a substantial body of both theoretical and empirical research. Amongst other factors, the low operational cost and simple maintenance procedures attributed the Oscillating Water Column (OWC) are perhaps the main reasons why this system is the most used concept for the ocean wave energy capture.In this paper, through extensive experimental research various geometrical designs of an OWC system is investigated and the optimized set up for the maximum energy harness is obtained.The initial chamber dimensions were 10 × 50 × 53 cm with the chamber being placed in an open channel with wave-simulating equipment with dimensions of 16 × 0.7 × .05 m. For various chamber geometries, with the aid of a air rotameter and a Pitot tube equipped with a digital manometer, the outlet air flow and velocity from the chamber was measured and registered.The measurements were then interpreted to provide design data for the optimal geometry of the chamber that may yield the maximum conversion of wave energy to useful energy.     

Vicious cycle during chemical degradation of sulfonated aromatic proton exchange membranes in the fuel cell application

Weak phase separation and vulnerable linking groups between aromatic units are common setbacks of sulfonated aromatic proton exchange membranes (PEMs) from durability point of view. In this study, sulfonated poly(ether ether ketone) (SPEEK) membranes were exposed to Fenton's solution for a specific time, ranging from 10 to 60 minutes. Chemical structure and morphology evolution, decay in mechanical and thermal stability, and H₂ permeability of SPEEK membranes were evaluated during the chemical degradation. Less-entangled polymeric chains with lower average molecular weight of degraded SPEEK samples diminished mechanical rigidity. In addition, reduction of aromatic rings in each repeat unit led to higher thermal decomposition rate. Furthermore, randomly distributed micro-defects in the SPEEK morphology and an increase in water sorption can reduce the fatigue strength of membranes in the wet-dry cycles. Eventually, hydrogen cross-over rate was gradually increased, and henceforth, accelerated destructive radical formation and degradation can be predicted.     

Exergetic and environmental performance improvement in cement production process by driving force distribution

This paper presents an investigation of the effects of temperature gradient distribution by the aid of a secondary burner on exergetic and environmental functions of the cement production process. For this reason, the burning system of the cement production (kiln &; preheater) process was simulated in four thermal areas. Three lines of cement production with 2,000, 2,300 and 2,600 ton/day were investigated. Fuel injection ratio into the secondary burner, from 10 to 40 percent was studied for each line. The obtained results show that, for cyclone preheaters, fuel injection into the secondary burner up to a proportion resulting in the minimum temperature required for alite formation (2,200 °C) in the kiln burning zone is suitable. For shaft preheaters, however, according to percent calcinations, there exists an optimum proportion for 15 to 20 percent injection fuel into secondary burner. Finally, it was shown that the secondary burner application can reduce the exergy losses about 25 percent, which leads to a reduction of the green house gases of about 35000 cubic meters per year for each ton per day of clinker production.     

Wrapping carbon nanotubes by biopolymer chains: Role of nanointerfaces in detection of vapors in conductive polymer composite transducers

Chitosan (CS) and hydrophobic‐modified chitosan (HM‐CS) chains were wrapped onto multiwalled carbon nanotubes (MWNTs) and introduced to polyvinyl alcohol (PVA) matrices as nanohybrid conductive polymer composites (CPCs) for detection of polar vapors. The effect of grafted alkyl groups on polarity of CS chains were studied by quantum mechanics (QM). The designed composites were applied as sensitive layers to clarify the response mechanism in CPCs gas sensors. It was realized that the wrapped biopolymers intensely influenced the sensitivity of the composites. Experiment results specified that the nature of biomacromolecules and their interactions with vapor molecules affects the resistance change in CPCs. The higher interaction of CS with polar vapor molecules caused more plasticization of polymer segments in the MWNTs connections. Such phenomenon enhanced the resistance change in the presence of analytes. Moreover, it was inferred that the semiconductor character of MWNTs has an important effect in the final signals. The more polar structure of CS in comparison with HM‐CS enhanced the adsorption of vapor molecules on the surface of MWNTs, and the electron donor analytes decreased the conductivity of p‐type MWNTs increasing the final responses. The presented results corroborate that the performance of CPCs gas sensors could be finely tuned through manipulation of the nanointerfaces. POLYM. COMPOS., 37:2803–2810, 2016. © 2015 Society of Plastics Engineers     

The effect of microencapsulation with nitrocellulose on thermal properties of sodium azide particles

Based on the coacervation principle a solvent/non-solvent method has been used for microencapsulation of sodium azide (NaN₃) with fibrous nitrocellulose (NC). Scanning electron microscopy (SEM) was employed to examine the coating morphology. The thermal behavior of solid samples has been studied by means of thermogravimetry (TG) and differential scanning calorimetry (DSC). The results of TG–DTA analysis revealed that the main thermal degradation for the pure NC and NaN₃ occurs in the temperature ranges of 192–220 and 415–420 °C, respectively. The effects of some parameters, such as NC to NaN₃ weight ratio and volume and addition time of non-solvent, on coating quality and thermal properties have been investigated by SEM and thermal methods. The results of these experiments showed that the decomposition temperature of most stabilized coated sodium azide is about 50 °C higher than that of the pure sample. The DSC experiments were conducted to study the influence of the heating rate (5, 10, 15 and 20 °C/min) on the thermal decomposition processes of the pure NC, coated and pure NaN₃ samples. The results revealed that, as the heating rate was increased, decomposition temperature of the compounds was increased. Also, the kinetic parameters such as activation energy and frequency factor of the decomposition processes were obtained from the DSC data by non-isothermal methods proposed by ASTM E696 and Ozawa. Our finding showed that coated NaN₃ has lower decomposition rate with respect to the pure one.