Catalytic activity of MnTUD-1 for liquid phase oxidation of ethylbenzene with tert-butyl hydroperoxide

Manganese was incorporated into silica matrix of TUD-1 using tetraethylene glycol (TEG) as the template. Three samples with Si/Mn ratio of 115, 44 and 18 were prepared and characterized by various techniques. MnTUD-1 is shown to be mesoporous with tetrahedrally coordinated Mn when Si/Mn?=?115; and nano-particles of manganese oxides are visible at higher loading of manganese (Si/Mn?=?44 and 18). The catalytic activity of MnTUD-1 was explored in the liquid-phase oxidation of ethylbenzene with tert-butylhydroperoxide (TBHP) as oxidant. Influence of various reaction parameters such as time, Si/Mn ratio, oxidant and solvent were studied. Finally the catalytic activity also compared with well-known microporous and mesoporous catalysts like MnAlPO-5, Mn containing MCM-41, MCM-48 and SBA-15.     

FEED-FORWARD BACK-PROPAGATION NEURAL NETWORK FOR THE ELECTRO-OXIDATION OF DISTILLERY EFFLUENT

The aim of the present work is to demonstrate the technical feasibility of treating high-strength distillery wastewater in an electrochemical flow reactor and to predict the result using an artificial neural network (ANN) model. The experiments were conducted using oxide coated on expanded titanium (Ti/Ru_0.3Ti_0.7O₂) as anode and stainless steel as cathode in a batch reactor with electrolytic recirculation. Pollutant degradation was measured as chemical oxygen demand (COD) for various operating parameters such as effluent flow rate, current density, and supporting electrolyte concentration. Experiments were conducted for various flow rates, supporting electrolyte concentrations, and current density. An ANN was used for modeling the experimental results. The model was developed using a feed-forward back-propagation network with different layers and neurons. It can be concluded that the network configuration of 3-3-3-1 simulation gives the best result in predicting the experimental results with a high correlation coefficient (R ² = 0.9987). Using this network model, the effluent COD removal can be predicted quickly and easily.     

Breast Cancer Detection in Saudi Arabian Women Using Hybrid Machine Learning on Mammographic Images

Breast cancer (BC) is the most common cause of women’s deaths worldwide. The mammography technique is the most important modality for the detection of BC. To detect abnormalities in mammographic images, the Breast Imaging Reporting and Data System (BI-RADs) is used as a baseline. The correct allocation of BI-RADs categories for mammographic images is always an interesting task, even for specialists. In this work, to detect and classify the mammogram images in BI-RADs, a novel hybrid model is presented using a convolutional neural network (CNN) with the integration of a support vector machine (SVM). The dataset used in this research was collected from different hospitals in the Qassim health cluster of Saudi Arabia. The collection of all categories of BI-RADs is one of the major contributions of this paper. Another significant contribution is the development of a hybrid approach through the integration of CNN and SVM. The proposed hybrid approach uses three CNN models to obtain ensemble CNN model results. This ensemble model saves the values to integrate them with SVM. The proposed system achieved a classification accuracy, sensitivity, specificity, precision, and F1-score of 93.6%, 94.8%, 96.9%, 96.6%, and 95.7%, respectively. The proposed model achieved better performance compared to previously available methods.     

Silicon‐based integrated millimeter‐wave CPW‐to‐dielectric image‐guide transition

In this article, a novel mm‐wave dielectric image‐guide (DIG) to CPW transition is proposed, fabricated, and successfully tested in the silicon technology. A DIG is implemented on high resistivity Silicon‐On‐Insulator (SOI) wafer. The image‐guide height and handle layer thickness are 500 μm and 130 μm, respectively. An Aluminum coplanar waveguide is patterned over the DIG. The measured transmission characteristics of the transition are in acceptable agreement with the simulation results. A transition (coupling) loss of about 1 dB has been achieved at 60 GHz. © 2014 Wiley Periodicals, Inc. Int J RF and Microwave CAE 24:490–497, 2014.     

Application of the accelerated Tafel plot technique to corrosion kinetics: Role of double layer through simulation

Results on the simulated -t transient response of an actively corroding system under accelerated Tafel plot (ATP) conditions have revealed the influence of input parameters (i, ) and system parameters (C _dl,i _corr andb) and explained the observed dependence of kinetic parameters (arrived at on the basis of the intercept-slope method) on in certain time domains. New improved methods, which eliminate such dependence and give uniform corrosion rate data over all time domains, are described in the paper.Nomenclature ATP accelerated Tafel plot - transfer coefficient - b Tafel slope (V) - C _d double layer capacitance (F cm^–2) - i initial value of the exponentially decaying current (A) - E _c corrosion potential (V) - overpotential (V) - n overpotential corresponding to maximum in -t transient (V) - F Faraday constant (C mol^–1) - i _corr corrosion current density (A cm^–2) - n number of electrons involved in charge transfer step - p intercept of ATP (V) - R gas constant (JK^–1 mol^–1) - R _p polarization resistance ( cm²) - S slope of ATP, i.e. d/dt (V) - S _av average of theS values at > _el (V) - S _meas slope of the linear -t region, i.e. d/dt (Vs^–1) - T temperature (K) - t time (s) - t _m time corresponding ton _m in the -t transient (s) - time constant of the exponentially decaying current pulse (s) - _el electrode time constant given byR _p C _d (s)     

Thermally stimulated depolarization currents in γ-irradiated β-spodumene solid solution ceramic

Thermally stimulated depolarization currents (TSDC) in unirradiated and -irradiated press prepared -spodumene solid solution ceramic have been investigated within the wide temperature range 20–160°C. Doses in the range 10–10⁵ Gy were used. The TSDC spectrum at relatively high polarizing fields shows two relaxation peaks whose positions and intensities depend on the polarization conditions and -doses. Discussion of data is given on the basis that dipolar and space-charge polarization coexist in the used ceramic material. Activation energies for space-charge peak are determined from the initial rise of thermal current peak under different -doses. Aging effect clearify that the longer the aging time, the smaller the polarization. Pyroelectric current data provide further support to space charge effects.     

Physicochemical and morphological evaluation of chitosan/poly(vinyl alcohol)/methylcellulose chemically cross-linked ternary blends

Chitosan/poly(vinyl alcohol)/methylcellulose (CS/PVA/MC) ternary blend was prepared and chemically cross-linked with glutaraldehyde. The prepared ternary blends were characterized by Fourier transform infrared spectroscopy (FTIR), Thermogravimetric analysis (TGA), and X-ray diffraction (XRD). The FTIR results showed that the strong intermolecular hydrogen bonds took place between CS and PVA. TGA showed the thermostability of the blend is enhanced by glutaraldehyde as crosslink agent. Results of XRD indicated that the relative crystalline of pure CS film was reduced when the polymeric network was reticulated by glutaraldehyde. Finally, the results of scanning electron microscopy (SEM) indicated that the morphology of the blend is rough and heterogenous, further it confirms the interaction between the functional groups of the blend components.     

Heavy metal removal from copper smelting effluent using electrochemical cylindrical flow reactor

The purpose of this study is mainly to evaluate the performance of the continuous recirculation flow cell at low current density and pH (the pH at which the effluents are available) in removing heavy metals from copper smelting effluent by cathodic reduction. During the electrolysis at different pH, % removal of heavy metals removal, energy consumption and heterogeneous reaction rate constants were investigated at given flow rate and current density on the selected industrial effluent. The overall specific energy consumption at the pH 0.64 was observed to be lowest, which is 10.99kWh/kg of heavy metal removal.     

Synthesis and characterization of nanocrystalline mesoporous zirconia using supercritical drying

Synthesis of nano-crystalline zirconia aerogel was done by sol-gel technique and supercritical drying using n-propanol solvent at and above supercritical temperature (235-280 degrees C) and pressure (48-52 bar) of n-propanol. Zirconia xerogel samples have also been prepared by conventional thermal drying method to compare with the super critically dried samples. Crystalline phase, crystallite size, surface area, pore volume, and pore size distribution were determined for all the samples in detail to understand the effect of gel drying methods on these properties. Supercritical drying of zirconia gel was observed to give thermally stable, nano-crystalline, tetragonal zirconia aerogels having high specific surface area and porosity with narrow and uniform pore size distribution as compared to thermally dried zirconia. With supercritical drying, zirconia samples show the formation of only mesopores whereas in thermally dried samples, substantial amount of micropores are observed along with mesopores. The samples prepared using supercritical drying yield nano-crystalline zirconia with smaller crystallite size (4-6 nm) as compared to higher crystallite size (13-20 nm) observed with thermally dried zirconia.     

Effect of fast neutrons and γ radiation on cobalt‐gelatin film

The real and imaginary parts of the dielectric constant (ε′ and ε″) were measured as a function of temperature at 10 kHz for a cobalt‐gelatin film before and after exposure to different values of fast neutron fluences and γ doses. The values of the ac conductivity were found to be affected to some extent by the type of irradiation in comparison with that of the unirradiated ones. However, the behavior of ε′, ε″, and ac conductivity seemed to be the same at higher and lower doses of both types of radiation. This behavior was also observed by comparing the calculated values of the activation energies for co‐gelatin films before and after irradiation. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 79: 1749–1755, 2001