Optimization of enzymatic extraction of ferulic acid from wheat bran,using response surface methodology,and characterization of the resulting fractions

BACKGROUND: The agro‐industries generate thousands of tons of by‐products, such as bran or pulps, each year. They are, at best, used for cattle feeding. Through biocracking, this biomass may constitute a renewable source for various molecules of interest for the industry. For instance, ferulic acid, a compound showing antioxidant ability, is found in abundance in cereal bran. Its release depends mainly on the breaking of its ester linkage to other constitutive elements of the cell wall, such as arabinoxylans. Response surface methodology was used to evaluate the effects of ferulic acid esterase (FAE) and xylanase activities, as well as incubation time and temperature, on ferulic acid extraction yield from wheat bran. Under optimized conditions, the composition of the hydrolysate and of residual bran were compared to native bran. RESULTS: Experiments carried out under the predicted optimal conditions (FAE amount, 27 U g^?1; xylanase amount, 304 U g^?1; incubation time, 2 h; and temperature, 65 °C) led to an extraction yield of 52.8%, agreeing with the expected value (51.0%). The crude ferulic acid fraction was purified with Amberlite XAD16, leading to a final concentration of 125 µg mL^?1 of ferulic acid in ethanol. The antioxidant capacity of this purified fraction was evaluated by the DPPH· scavenging method: it exhibited better efficiency (EC₅₀ = 10.6 µmol L^?1 in ferulic acid) than the ferulic acid standard (EC₅₀ = 13.7 µmol L^?1). CONCLUSION: These results confirm the potential of wheat bran valorization in the field of natural antioxidant extraction, possibly viable in an industrial scheme. Copyright © 2009 Society of Chemical Industry     

Study the Heat Recovery Performance of Micro and Nano Metfoam Regenerators in Alpha Type Stirling Engine Conditions

This paper experimentally investigates the performance of micro and nano metfoam regenerators in alpha-type Stirling engine conditions. The thermal efficiency of this engine depends on performance of regenerator. Therefore, increase the heat recovery of regenerator raises the total efficiency. Accordingly, two types of regenerators from porous media are designed and simulated with different materials. Three-dimensional regenerator CFD simulation shows that randomize porous open cell metfoam made of silver as high conductivity and high heat capacity material is the best structure to fabricate metfoam regenerator. The porosity and matrix element diameter are optimized. The nano coating methodology enhances the activated surface. The regenerators are fabricated using casting polymer mold layer deposition. The nano silver particles are coated on the metfoam by sol-gel coating method. Experimental results show the improvement in regenerator percentage of heat recovery by 3.40% and 5.93% for micro metfoam and nano metfoam, respectively. The maximum improvement is achieved up to 8.65% in case of using the nano metfoam regenerator at 543 K.     

New sulfonated aramide nanoparticles and their copper complexes with anomalous dielectric behavior

We report the preparation of thermally stable spherical sulfonated aramides nanoparticles and their copper(II) complexes. Metal chelation with copper ions furnished polymeric complexes in a 1 : 2 ratio with square planar geometries as judged by their IR, UV, electron spin resonance, and elemental analysis data. The direct‐current electrical conductivities demonstrated the semiconducting nature of the polymeric particles and their copper complexes. Dielectric loss analysis studies showed spectral peaks appearing at characteristic frequencies, which suggested the presence of relaxing dipoles in all of the polymers. All loss peaks were shown on a linear frequency scale and appeared in the range of 1 decade, and no overlap was observed in any of the samples, whereas in the normal polymer's dielectric loss behavior, each peak covered more than 1 decade. Moreover, the peak positions did not change with increasing temperature; this indicated a nonactivated process. The reported dielectric results revealed anomalous behavior, which has not been reported before for such polymeric analogues, as the polarization in these cases was limited by nonthermal forces, and a steady‐state constant polarization was produced by an applied field. A simple method for the formation of a microporous semiconducting thin film of a polymer derived from isophthalic acid and diaminodiphenylsulfone is described. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Biosourced vanillin Schiff base platform monomers as substitutes for DGEBA in thermoset epoxy

Diglycidyl ether Schiff base monomers were prepared from vanillin and various diamines. FT-IR, ¹H NMR, ¹³C NMR, and mass spectroscopy were used to determine their structure. Cured thermoset epoxies made with them were compared to commercial epoxy in terms of mechanical properties. Tensile strengths ranged from 35.1 to 60.4 MPa, Young's modulus from 3.9 to 6.9 GPa, similar to the commercial product. The glass transition ranged from 80 to 117°C, the phase transition T_α from 80 to 121°C and the storage modulus from 2 to 3.5 GPa. Thermogravimetric analysis showed that the vanillin-based epoxies were less heat resistant but had higher residual mass (20-30% wt/wt). Hydrolysis, hydrophobicity and degradation were also monitored to evaluate their potential for coating applications.     

SAFT-VNDN: A Socially-Aware Forwarding Technique in Vehicular Named Data Networking

Vehicular Social Networks (VSNs) is the bridge of social networks and Vehicular Ad-Hoc Networks (VANETs). VSNs are promising as they allow the exchange of various types of contents in large-scale through Vehicle-to-Vehicle (V2V) and Vehicle-to-Infrastructure (V2I) communication protocols. Vehicular Named Data Networking (VNDN) is an auspicious communication paradigm for the challenging VSN environment since it can optimize content dissemination by decoupling contents from their physical locations. However, content dissemination and caching represent crucial challenges in VSNs due to short link lifetime and intermittent connectivity caused by vehicles’ high mobility. Our aim with this paper is to improve content delivery and cache hit ratio, as well as decrease the transmission delay between end-users. In this regard, we propose a novel hybrid VNDN-VSN forwarding technique based on social communities, which allows requester vehicles to easily find the most suitable forwarder or producer among the community members in their neighborhood area. Furthermore, we introduce an effective caching mechanism by dividing the content store into two parts, one for community private contents and the second one for public contents. Simulation results show that our proposed forwarding technique can achieve a favorable performance compared with traditional VNDN, in terms of data delivery ratio, average data delivery delay, and cache hit ratio.     

Dipper Throated Algorithm for Feature Selection and Classification in Electrocardiogram

Arrhythmia has been classified using a variety of methods. Because of the dynamic nature of electrocardiogram (ECG) data, traditional handcrafted approaches are difficult to execute, making the machine learning (ML) solutions more appealing. Patients with cardiac arrhythmias can benefit from competent monitoring to save their lives. Cardiac arrhythmia classification and prediction have greatly improved in recent years. Arrhythmias are a category of conditions in which the heart's electrical activity is abnormally rapid or sluggish. Every year, it is one of the main reasons of mortality for both men and women, worldwide. For the classification of arrhythmias, this work proposes a novel technique based on optimized feature selection and optimized K-nearest neighbors (KNN) classifier. The proposed method makes advantage of the UCI repository, which has a 279-attribute high-dimensional cardiac arrhythmia dataset. The proposed approach is based on dividing cardiac arrhythmia patients into 16 groups based on the electrocardiography dataset’s features. The purpose is to design an efficient intelligent system employing the dipper throated optimization method to categorize cardiac arrhythmia patients. This method of comprehensive arrhythmia classification outperforms earlier methods presented in the literature. The achieved classification accuracy using the proposed approach is 99.8%.     

Influence of Optimized Tire Shreds on Shear Strength Parameters of Sand

This paper presents the usefulness of optimizing the size of waste tire shreds on shear strength parameters of sand reinforced with shredded waste tires. A relatively, uniform sand has been mixed with randomly distributed waste tire shreds with rectangular shape and compacted at 2° of compaction. Waste tire shreds were prepared with a special cutter in three widths of 2, 3, and 4?cm and various lengths for each shred width. Three shred contents of 15, 30, and 50% by volume were chosen and mixed with the sand to obtain a uniformly distributed mixture. In order to compare the shear strength of different sand–tire shred samples, two compaction efforts in terms of sand matrix unit weights of 15.5 and 16.8?kN/m3 were considered. The results show that the influencing parameters on shear strength characteristics of sand–shred mixtures are normal stress, sand matrix unit weight, shred content, shred width, and aspect ratio of tire shreds. With the selected widths of shreds, compaction efforts, shred contents, and the variations of aspect ratios, it is possible to increase the initial friction angle ?1 up to 113.5%, that is ?1 = 67°. The average value for the influence of aspect ratio variations on increase in friction angle of the mixtures for all tests has been found to be about 25%. These average values for lower and higher compacted samples containing different widths and aspect rations were 37.6 and 17.2%, respectively. It has been investigated that for a given width of tire rectangular shreds, there is solely a certain length, which gives the greatest initial friction angle for sand–tire shred mixtures. This is the main contribution of this paper.