Production of aromatics by catalytic fast pyrolysis of cellulose in a bubbling fluidized bed reactor

Catalytic fast pyrolysis of cellulose was studied at 500°C using a ZSM‐5 catalyst in a bubbling fluidized bed reactor constructed from a 4.92‐cm ID pipe. Inert gas was fed from below through the distributor plate and from above through a vertical feed tube along with cellulose. Flowing 34% of the total fluidization gas through the feed tube led to the optimal mixing of the pyrolysis vapors into the catalyst bed, which experimentally corresponded to 29.5% carbon aromatic yield. Aromatic yield reached a maximum of 31.6% carbon with increasing gas residence time by changing the catalyst bed height. Increasing the hole‐spacing in the distributor plate was shown to have negligible effect on average bubble diameter and hence did not change the product distribution. Aromatic yields of up to 39.5% carbon were obtained when all studied parameters were optimized. © 2014 American Institute of Chemical Engineers AIChE J, 60: 1320–1335, 2014     

Bio-/Environment-Friendly Cationic Gemini Surfactant as Novel Corrosion Inhibitor for Mild Steel in 1 M HCl Solution

Bio-/environment-friendly cationic gemini surfactant, ethane-1,2-diyl bis(N,N-dimethyl-N-hexadecylammoniumacetoxy)dichloride, referred to as 16-E2-16, was synthesized and characterized. Corrosion inhibition effects of 16-E2-16 on mild steel (MS) surface in 1 M HCl solution at 30, 40, 50 and 60 °C were evaluated using gravimetric analysis, potentiodynamic polarisation and electrochemical impedance spectroscopy measurements. The nature of the protective inhibitor film formed on the MS surface was analysed by SEM, EDAX and FT-IR, while TGA was used to assure the thermal behaviour and stability of the film at high temperature. The formation of [inhibitor-Fe²⁺] on the surface of MS was confirmed by UV–visible spectroscopy. The inhibition efficiency of the studied inhibitor increased with increasing concentration and solution temperature. The compound behaved as a mixed type inhibitor and acted by blocking the electrode surface by means of adsorption obeying the Langmuir adsorption isotherm. Surface active properties and corrosion inhibition effects of 16-E2-16 in the presence of inorganic (NaI) and organic (NaSal) salts were also investigated and are discussed. Density functional theory calculations have been carried out to correlate the efficiency of the compound with its intrinsic molecular parameters.     

Influence of Growth Conditions on Magnetite Nanoparticles Electro-Crystallized in the Presence of Organic Molecules

Magnetite nanoparticles were synthesized by electrocrystallization in the presence of thiourea or sodium butanoate as an organic stabilizer. The synthesis was performed in a thermostatic electrochemical cell containing two iron electrodes with an aqueous solution of sodium sulfate as electrolyte. The effects of organic concentration, applied potential and growth temperature on particle size, morphology, structure and magnetic properties were investigated. The magnetite nanoparticles were characterized by X-ray diffraction, electron microscopy, magnetometry and Mössbauer spectrometry. When the synthesis is performed in the presence of sodium butanoate at 60 °C, a paramagnetic ferric salt is obtained as a second phase; it is possible to avoid formation of this phase, increase the specific magnetization and improve the structure of the oxide particles by tuning the growth conditions. Room-temperature magnetization values range from 45 to 90 Am²kg⁻¹, depending on the particle size, type of surfactant and synthesis conditions. Mössbauer spectra, which were recorded at 290 K for all the samples, are typical of nonstoichiometric Fe_3−δO₄, with a small excess of Fe³⁺, 0.05 ≤ δ ≤ 0.15.     

Improved quadtree image segmentation approach to region information

Images are full of information and most often, little information is desired for subsequent processing. Hence, region of interest has key importance in image processing. Quadtree image segmentation has been widely used in many image processing applications to locate the region of interest for further processing. There are also variable block-size image coding techniques to effectively reduce the number of transmitted parts. This paper presents quadtree partition technique as a pre-processing step in image processing to determine what part should be more heterogeneous than the others. It also introduces an idea to solve the problem of squared images. Finally, proposed approach is implemented and analysed. The simulation of the Matlab code of the quadtree is represented by all algorithms and the figures. Thus, achieved results are promising in the state of the art.     

Magnetic resonance image denoising using nonlocal maximum likelihood paradigm in DCT‐framework

The data acquired by magnetic resonance (MR) imaging system are inherently degraded by noise that has its origin in the thermal Brownian motion of electrons. Denoising can enhance the quality (by improving the SNR) of the acquired MR image, which is important for both visual analysis and other post processing operations. Recent works on maximum likelihood (ML) based denoising shows that ML methods are very effective in denoising MR images and has an edge over the other state‐of‐the‐art methods for MRI denoising. Among the ML based approaches, the Nonlocal maximum likelihood (NLML) method is commonly used. In the conventional NLML method, the samples for the ML estimation of the unknown true pixel are chosen in a nonlocal fashion based on the intensity similarity of the pixel neighborhoods. Euclidean distance is generally used to measure this similarity. It has been recently shown that computing similarity measure is more robust in discrete cosine transform (DCT) subspace, compared with Euclidean image subspace. Motivated by this observation, we integrated DCT into NLML to produce an improved MRI filtration process. Other than improving the SNR, the time complexity of the conventional NLML can also be significantly reduced through the proposed approach. On synthetic MR brain image, an average improvement of 5% in PSNR and 86%reduction in execution time is achieved with a search window size of 91 × 91 after incorporating the improvements in the existing NLML method. On an experimental kiwi fruit image an improvement of 10% in PSNR is achieved. We did experiments on both simulated and real data sets to validate and to demonstrate the effectiveness of the proposed method. © 2015 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 25, 256–264, 2015     

An improved strategy for skin lesion detection and classification using uniform segmentation and feature selection based approach

Melanoma is the deadliest type of skin cancer with highest mortality rate. However, the annihilation in early stage implies a high survival rate therefore, it demands early diagnosis. The accustomed diagnosis methods are costly and cumbersome due to the involvement of experienced experts as well as the requirements for highly equipped environment. The recent advancements in computerized solutions for these diagnoses are highly promising with improved accuracy and efficiency. In this article, we proposed a method for the classification of melanoma and benign skin lesions. Our approach integrates preprocessing, lesion segmentation, features extraction, features selection, and classification. Preprocessing is executed in the context of hair removal by DullRazor, whereas lesion texture and color information are utilized to enhance the lesion contrast. In lesion segmentation, a hybrid technique has been implemented and results are fused using additive law of probability. Serial based method is applied subsequently that extracts and fuses the traits such as color, texture, and HOG (shape). The fused features are selected afterwards by implementing a novel Boltzman Entropy method. Finally, the selected features are classified by Support Vector Machine. The proposed method is evaluated on publically available data set PH2. Our approach has provided promising results of sensitivity 97.7%, specificity 96.7%, accuracy 97.5%, and F‐score 97.5%, which are significantly better than the results of existing methods available on the same data set. The proposed method detects and classifies melanoma significantly good as compared to existing methods.     

pH Responsive Abelmoschus esculentus Mucilage and Administration of Methotrexate: In-Vitro Antitumor and In-Vivo Toxicity Evaluation

The rapid progression in biomaterial nanotechnology apprehends the potential of non-toxic and potent polysaccharide delivery modules to overcome oral chemotherapeutic challenges. The present study is aimed to design, fabricate and characterize polysaccharide nanoparticles for methotrexate (MTX) delivery. The nanoparticles (NPs) were prepared by Abelmoschus esculentus mucilage (AEM) and chitosan (CS) by the modified coacervation method, followed by ultra-sonification. The NPs showed much better pharmaceutical properties with a spherical shape and smooth surface of 213.4–254.2 nm with PDI ranging between 0.279–0.485 size with entrapment efficiency varying from 42.08 ± 1.2 to 72.23 ± 2.0. The results revealed NPs to possess positive zeta potential and a low polydispersity index (PDI). The in-vitro drug release showed a sustained release of the drug up to 32 h with pH-dependence. Blank AEM -CS NPs showed no in-vivo toxicity for a time duration of 14 days, accompanied by high cytotoxic effects of optimized MTX loaded NPs against MCF-7 and MD-MBA231 cells by MTT assay. In conclusion, the findings advocated the therapeutic potential of AEM/CS NPs as an efficacious tool, offering a new perspective for pH-responsive routing of anticancer drugs with tumor cells as a target.     

Cu-K/Al2O3 based catalysts for conversion of carbon dioxide to methane and carbon monoxide

Abstract

A series of Cu-K/Al₂O₃ catalysts were synthesized by wet impregnation technique. The reduced catalysts were further used for conversion of carbon dioxide to methane and carbon monoxide. Moreover, the fresh and used catalysts were characterized to investigate the changes in the surface morphology, metal dispersion, surface area, crystalline phases, and functional groups of studied catalysts. The SEM analysis of fresh and spent catalysts showed no remarkable difference in surface morphology with irregular shaped agglomerated particles. Furthermore, TEM micrographs presented the well distribution of metal catalyst over alumina support. The decrease in surface area from 115 to 77?m²/g for Cu_1.62-K_0.5/Al₂O₃ after reaction was related to sintering and oxidation of catalyst during reaction. XRD revealed the disappearance of some minor peaks which can be associated with the sintering of spent catalyst. FTIR also presented some new peak for spent catalyst which can be linked with metal oxides. Moreover, various reaction conditions of temperature (230, 400, and 600?°C), pressure (1 and 7?bar), and feed molar ratio of H₂/CO₂ (2:1 and 4:1) were investigated using different Cu loading (0, 1, 1.25, 1.62, and 4 weight percent). A maximum CO₂ conversion of 63% with 39% CH₄ selectivity was achieved by using Cu_1.62-K_0.5/Al₂O₃ at 600?°C, molar ratio of H₂/CO₂ 4 under 7?bar. The presence of K on the surface of synthesized catalyst increased the CO₂ conversion from 48% (Cu₁/Al₂O₃) to 55% (Cu₁-K_0.5/Al₂O₃) at above mentioned reaction conditions which suggested the promoter effect of K during conversion of carbon dioxide.     

Magnetron sputtered Dy_2O_3 with chromium and copper contents for antireflective thin films with enhanced absorption

Dy_2O_3 is a rare earth oxide having a number of advanced applications in various fields including protective or antireflective coatings, Main objective of this novel research work is to check the effect of Cr and Cu addition on different properties of Dy_2O_3 and achievement of antireflective thin films with enhanced abso rption. Thin films of these materials we re deposited using DC magnetron with reactive cosputtering. XRD studies reveals the crystalline nature of thin films having Dy_2O_3(222) reflection in all samples with Cr_2O_3(116) and CuO(111) reflections in Cr and Cu containing compositions. Field emission scanning electron microscopy demonstrates the homogeneous deposition of thin films with uniform shape, size and distribution of grains. Refractive index, extinction coefficient and absorption coefficient significantly increase while optical reflectance decreases with Cr and Cu mediation corroborating an improved antireflective mechanism. The imaginary part of dielectric constant is found to increase slightly with low tangent loss for Cr containing composition co nsidered favorable for energy storage applications.