High efficient corrosion inhibitor of water-soluble polypyrrole–sulfonated melamine formaldehyde nanocomposites for 316 L stainless steel

In this work, new water-soluble polypyrrole–sulfonated melamine formaldehyde nanocomposites (PPy–SMF NCs) were first synthesized by one-step in-situ polymerization of pyrrole with FeCl₃ in the presence of various mole ratios of sulfonated melamine formaldehyde (SMF). The characterization of the PPy–SMF NCs was investigated via ultraviolet–visible spectroscopy, Fourier transform infrared spectroscopy, scanning electron microscopy, energy dispersive X-ray, dynamic light scattering, transmission electron microscopy, X-ray diffraction, thermogravimetric analysis, differential scanning calorimetry, and conductivity measurements. The resulting PPy–SMF NCs were proved to improve the solubility, electrical properties, and thermal stability. The anti-corrosion performance of PPy-SMF NCs on 316 L stainless steel (316 L SS) was examined using electrochemical impedance spectroscopy, potentiodynamic polarization, and weight-loss method. The result showed that the PPy–SMF NCs acts as a mixed-type inhibitor, as well as a protective layer to 316 L SS against corrosion in 3.5% NaCl solution. The Langmuir adsorption isotherm was well fitted and suitable to explain the adsorption behavior of the PPy-SMF NCs on 316 L SS surface. The inhibition efficiency of PPy-SMF NCs is 99% by the weight-loss method which could be attributed to the protective layer formed on 316 L SS surface by the adsorption of PPy-SMF NCs.     

Stability analysis and implementation of chopper fed DC series motor with hybrid PID-ANN controller

The attempt is made to enhance the performance of a closed loop control of DC series motor fed by DC chopper (DC-DC buck converter) by hybridization of PID controller with an intelligent control using ANN (Artificial Neural Network) controller. This system consists of inner current controller loop and outer PID-ANN based speed controller loop. The current controller allows the PWM (Pulse Width Modulation) signal when the motor current is less than set value. The PID-ANN speed controller controls the motor voltage by controlling the duty cycle of the chopper thereby the motor speed is regulated. The PID-ANN controller performances are analyzed in both steady state and dynamic operating condition with various set speed and various load torque. The rise time, maximum over shoot, settling time, steady state error and speed drops are taken for comparison with conventional PID controller and existing work. The steady state stability analysis of the system also is made by using the transfer function model with MATLAB. The training data for PID-ANN controller is taken from conventional PID controller. The Hybrid PID-ANN controller with DC chopper has better control over the conventional PID controller and the reported existing work. This system is simulated using MATLAB/Simulink and also it is implemented with a NXP 80C51 family Microcontroller (P89V51RD2 BN) based Embedded System.     

Preparation,characterization, and functional analysis of zinc oxide nanoparticle-coated cotton fabric for antibacterial efficacy

Nanotechnology is an emerging interdisciplinary technology and nanostructures capable of enhancing the physical properties of conventional textiles in areas such as antimicrobial properties, water repellence, soil resistance, antistatic, anti-infrared and flame-retardant properties, dye ability, color fastness, and strength of textile materials. The studies were carried out in order to fine tune the preparation of zinc oxide nanoparticles (NPs) for special applications. Soluble starch (stabilizing agent), zinc nitrate and sodium hydroxide (precursors) were used for the preparation of zinc oxide NPs by wet chemical method. The synthesized NPs were coated on cotton fabric (plain weave), and the antibacterial property of the treated fabric was analyzed. Fourier transform infrared spectroscopic analysis, scanning electron microscopy, and physical and chemical characterization were employed to determine the phase and morphology of the final nanoparticle-coated fabric. The results indicated that 2% zinc oxide nanoparticle (200 nm) -coated fabric have high antibacterial efficiency (99.9% against Staphylococcus aureus and 80% against Escherichia coli) and upon washing the coated fabric (five hand washes), the antibacterial activity was found to be 98% against S. aureus and 75% against Escherichia coli.     

Dual chemosensing properties of new ferrocene-based receptors towards fluoride and copper(II) ions

The new ferrocene based receptors N-[4-ferrocenyl-2-methyl-4-oxobut-1-enyl]-N′-phenylthiourea (1), N-[4-ferrocenyl-2-methyl-4-oxobut-1-enyl]-N′-[4-nitrophenyl]thiourea (2) were synthesized and characterized. Fluorescence titrations of receptors 1 and 2 with various transition metal ions showed selective response to Cu²⁺ ions and the emission intensities quenched significantly. Electrochemical titrations with anions revealed that receptors 1 and 2 sensed the F⁻ anion in high selectivity with a cathodic shift of 100 mV.     

Unstructured Oncological Image Cluster Identification Using Improved Unsupervised Clustering Techniques

This paper presents, a new approach of Medical Image Pixels Clustering (MIPC), aims to trace the dissimilar patterns over the Magnetic Resonance (MR) image through the process of automatically identify the appropriate number of distinct clusters based on different improved unsupervised clustering schemes for enrichment, pattern predication and deeper investigation. The proposed MIPC consists of two stages: clustering and validation. In the clustering stage, the MIPC automatically identifies the distinct number of dissimilar clusters over the gray scale MR image based on three different improved unsupervised clustering schemes likely improved Limited Agglomerative Clustering (iLIAC), Dynamic Automatic Agglomerative Clustering (DAAC) and Optimum N-Means (ONM). In the second stage, the performance of MIPC approach is estimated by measuring Intra intimacy and Intra contrast of each individual cluster in the result of MR image based on proposed validation method namely Shreekum Intra Cluster Measure (SICM). Experimental results show that the MIPC approach is better suited for automatic identification of highly relative dissimilar clusters over the MR cancer images with higher Intra closeness and lower Intra contrast based on improved unsupervised clustering schemes.     

Non-invasive evaluation of carotid artery wall thickness using improved dynamic programming technique

An improved dynamic programming (DP) segmentation technique for detecting the intima-media layer of the far wall of the common carotid artery (CCA) of longitudinal and transversal ultrasound (US) images using optimal search technique is presented here. The algorithm is developed considering the normalization and smoothing for estimating the intima media thickness (IMT) of the normal and abnormal subjects. The segmentation features of different subjects obtained using the proposed technique have been compared with the manual measurements. The results show that an inter-observer error and a coefficient of variation are found as ±0.035 mm and 3.55%, respectively. The magnitudes of the IMT values have been used to explore the rate of prediction of blockage existing in the cerebrovascular and cardiovascular pathologies, and also hypertension and atherosclerosis.     

Lewis acidic mesoporous Fe-TUD-1 as catalysts for synthesis of Hantzsch 1,4-dihydropyridine derivatives

Lewis acidic mesoporous material (TUD-1) containing Fe was investigated as stable and reusable catalyst for the synthesis of Hantzsch 1,4-dihydropyridine (DHP) derivatives. Yields between 76 and 91 % of DHP derivatives were obtained in shorter reaction times of 3 h depending on the nature of substituents in benzaldehyde.     

Attic radiant barrier systems: A sensitivity analysis of performance parameters

During the past seven years, the Florida Solar Energy Center (FSEC) has conducted extensive experimental research on radiant barrier systems (RBS). This paper presents recent research on the development of mathematical attic models and results from a sensitivity analysis of RBS performance parameters. Two levels of modelling capability have been developed. A very simplified model based on ASHRAE procedures is used to study the sensitivity of RBS performance parameters, and a very detailed finite-element model is used to study highly complex phenomena, including moisture adsorption and desorption in attics. The speed of the simple model allows a large range of attic parameters to be studied quickly, and the finite-element model provides a detailed understanding of combined heat and moisture transport in attics. This paper concentrates on the sensitivity analysis of attic RBS performance parameters using the simplified model. The development of the model is described, and results of the analyses are presented and discussed. Results from the finite-element model are also presented and compared with measurements from a test attic to illustrate the effects of moisture adsorption and desorption in common attics. The simplified steady-state model shows excellent agreement with measured steady-state data when thermal stratification of the attic air is modelled. Results of the sensitivity analysis using this model show that the radiant barrier surface emittance and the attic ventilation inlet air temperature are the most sensitive performance parameters for attic radiant barrier systems. The detailed, finite-element model shows that moisture sorption phenomena can have significant effects in attics. The daily temperature extremes in attics are significant, and they induce a moisture flux at the surfaces of the materials bounding the air zone(s). If this moisture flux is not accounted for in detail (i.e. with fully coupled heat and moisture transport equations) inaccurate surface temperature predictions are likely to occur.