Activating pulp toward acetylation by chemical or mechanical means

Activation of pulps during acetylation, by prior mechanical or chemical treatment, has been investigated. The effect of degree of beating on the acetylation rate of wood and bagasse pulps has been studied. It is found that the acetylation rate of pulps increases when the degree of beating of pulps is increased to a definite degree, after which it slows down. The maximum reactivity of bagasse pulp is obtained at 50°SR, while that of wood pulp is observed at 30°SR. The effect of grafting of acrylonitrile onto bagasse and wood pulps on their reactivity during acetylation has been also studied. The results indicate that grafting of acrylonitrile onto pulps has a favorable effect on their acetylation rate. This is dependent on the degree of grafting as well as the origin of pulp fibers. The most suitable method of activation during acetylation reaction is dependent on the origin of the pulp. The reactivity of bagasse pulp during acetylation is influenced more by beating of pulp, prior to the reaction, than by the grafting of acrylonitrile onto pulp. On the other hand, the acetylation reaction of wood pulp is activated by grafting rather than by beating. Also the effect of the activation process, mechanical or chemical, on the strength properties of the paper sheets produced from acetylated pulps has been investigated. Chemical activation of wood pulp prior to acetylation resulted in pulp with slightly higher strength properties than that activated by mechanical means. But, in the case of bagasse pulp, mechanical activation resulted in a pulp with strength superior to that produced by chemical activation.     

Corrosion inhibition of triethanolammonium bromide mono- and dibenzoate as cationic inhibitors in an acidic medium

A weight loss technique was used to determine the corrosion inhibition efficiency of synthesized alkyl mono-and dibenzoate triethanolammonium bromide derivatives (TEAMB, TEADB) in an acidic medium (2 N HCl) at different doses (50, 100, and 200 ppm). The results showed that monoderivatives had a higher corrosion inhibition efficiency than diderivatives. The results were correlated with several factors, including the alkyl chain length of the hydrophobic chains, interfacial tension (IT), critical micelle concentration (CMC), and adsorption free energy of these inhibitors. Increasing the geometric length of the alkyl chains in the synthesized inhibitors had an increasing effect on their corrosion inhibition efficiency, whereas decreasing the CMC and IT had an increasing effect on their tendency toward corrosion inhibition. The number of hydrophobic chains attached to the inhibitor molecules had a vital influence on their efficiency as corrosion inhibitors.     

Identifying Objects in Procedural Programs Using Clustering Neural Networks

This paper presents a general approach for the identification of objects in procedural programs. The approach is based on neural architectures that perform an unsupervised learning of clusters. We describe two such neural architectures, explain how to use them in identifying objects in software systems and briefly describe a prototype tool, which implements the clustering algorithms. With the aid of several examples, we explain how our approach can identify abstract data types as well as groups of routines which reference a common set of data. The clustering results are compared to the results of many other object identification techniques. Finally, several case studies were performed on existing programs to evaluate the object identification approach. Results concerning two representative programs and their generated clusters are discussed.     

Encrypted gray image transmission over OFDM channel for TV cloud computing

One of the most important issues which attract the researcher is to provide a secure channel to transfer data between many points. Television cloud has many contents which are needed to be transferred to authorized groups (AuthGs). Also, the transfer rate is an aspect to be considered. In this work, orthogonal frequency division multiplexing is investigated to be sure it is acceptable for the cloud and use many transforms to choose the perfect one for the cloud. The investigation is done under fading channel condition. Peak signal-to-noise ratio is used to differentiate between cases. Many tests are also suggested to confirm the high quality of performance for the cloud.     

Facile Synthesis of ZSM-5/TiO2/Ni Novel Nanocomposite for the Efficient Photocatalytic Degradation of Methylene Blue Dye

It is critical to develop an appropriate dye degrading technique to preserve the natural environment and human health owing to the dangerous water pollution caused by effluent dyes. So, in this work, a ZSM-5/TiO₂/Ni photocatalyst was synthesized as a novel composite and used for degrading methylene blue dye in the solution. The sol–gel approach was used to immobilize titanium dioxide nanoparticles on the ZSM-5 surface, and the resulting photocatalyst was then modified using nickel nanoparticles to improve its photocatalytic performance. The nanocomposite was characterized using different tools such as FE-SEM, EDX, XRD, FT-IR, TGA, and UV–Vis spectrophotometer. The XRD confirmed that the synthesized composite has the characteristic TiO₂ peaks. FE-SEM images of ZSM-5 exhibited rough, uneven, and jagged surfaces. A distinct shift in the morphology of the surface resulted when titanium dioxide was fully immobilized on the surface of ZSM-5. Shape complexity and surface roughness of the particles are elevated in the case of the ZSM-5/TiO₂/Ni nanocomposite. The maximum % degradation of 50 mL of 15 mg/L of methylene blue dye is 99.17% and achieved at pH?=?8, irradiation time?=?140 min, and photocatalyst dosage?=?0.05 g. The synthesized composite can be regenerated and reused several times without losing its efficacy.

     

An FPGA implementation of a neural optimization of block truncation coding for image/video compression

This paper presents a Field Programmable Gate Array (FPGA) implementation for image/video compression using an improved block truncation coding (BTC) image compression technique. The improvement is achieved by employing a Hopfield neural network (HNN) to calculate a cost function upon which a block is classified as either a high- or a low-detail block. Accordingly, different blocks are coded with different bit rates and thus resulting in better compression ratios. The paper formulates the utilization of HNN within the BTC algorithm in such a way that a viable FPGA implementation is produced. The implementation exploits the inherent parallelism of the BTC/HNN algorithm to provide efficient algorithm-to-architecture mapping. The Xilinx VirtexE BTC implementation has shown to provide a processing speed of about 1.113 × 10⁶ of pixels per second with a compression ratio which varies between 1.25 and 2 bits/pixel, according to the image nature.     

Fuzzy logic-based pre-classifier for tropical wood species recognition system

Classifying tropical wood species poses a considerable economic challenge and failure to classify the wood species accurately can have significant effects on timber industries. The problem of wood recognition is compounded with the nonlinearities of the features among the similar wood species. Besides that, large wood databases presented a problem of large processing time especially for online wood recognition system. In view of these problems, we propose the use of fuzzy logic-based pre-classifier as a means of treating uncertainty to improve the classification accuracy of tropical wood recognition system. The pre-classifier serve as a clustering mechanism for the large database simplifying the classification process making it more efficient. The use of the fuzzy logic-based pre-classifier has managed to increase the accuracy of the wood recognition system by 4 % and reduce the processing time for training and testing by more than 75 % and 26 % respectively.     

Characterization of cobalt oxide nanocatalysts prepared by microemulsion with different surfactants, reduction by hydrazine and mechanochemical method

Cobalt oxide (Co₃O₄) nanoparticles were prepared by different techniques (i) by microemulsion with different surfactants, (ii) by reduction as nanometal with hydrazine hydrates and (iii) by thermal treatment of precursor obtained from mechanochemical reaction of Co(NO₃)·H₂O with NH₄HCO₃. The products were calcined at 400 °C to give crystalline Co₃O₄. The obtained different samples of Co₃O₄ were characterized using X-ray diffraction (XRD) and transmission electron microscopy (TEM) from which the particle size was calculated. The results revealed that all samples obtained from different methods were nanosized particles.