Toward the development of an innovative descaling and corrosion inhibiting solutions to protect mild steel equipment: an experimental and theoretical approach

Abstract

This work proposes a mixture of sulfamic and perchloric acids as a descaling solution and cetyltrimethyl ammonium bromide (CTAB) and imidazole for the improvement in the corrosion resistance of mild steel. The experiments were carried out at different temperatures using mass loss and electrochemical techniques. The samples were characterized by inductively coupled plasma spectrometry, SEM-EDS, and X-ray diffraction techniques. The study showed that CTAB and imidazole can serve as the efficient corrosion inhibitors for mild steel in descaling solution and were found to follow the model of Langmuir adsorption isotherm. Potentiodynamic polarization was performed at temperature 295, 305, 315, and 325?K, and it can be concluded that the CTAB/imidazole acted as mixed type corrosion inhibitors. Electrochemical impedance spectroscopy studies revealed that increase in imidazole concentration, resulted into the increased polarization resistance with simultaneous lowering of double-layer capacitance values. Computational techniques were used to support experimental results.     

Effects of water-soluble polymers and aqueous-phase viscosity on the interfacial tension behavior of reacting oil–alkaline systems

This study presents the results of an experimental study of the effects of water-soluble polymer additives on the dynamic interfacial tension behavior of reacting oil–aqueous systems as measured by the spinning drop tensiometer. Polymer additives can exert both a direct physico-chemical effect and an indirect viscosity effect on the measured interfacial tension. This work, which complements an earlier study dealing with the effects of oil-soluble polymer additives, reveals that the nominal effects of aqueous-phase viscosity are opposite to those of oil-phase viscosity. In particular, an increase in aqueous-phase viscosity produces an increase in the rate of increase of the apparent interfacial tension after attainment of the minimum value. These differences are explained in terms of the dependence of diffusion rates and interfacial adsorption on aqueous-phase viscosity. The conclusion of principal practical interest is that although aqueous-phase viscosity exerts only a small effect on the dynamic interfacial tension at small times (i.e., prior to attainment of the minimum value) it exerts a very significant effect thereafter. © 1994 John Wiley & Sons, Inc.     

Inverse modelling and pulsating torque minimization of salient pole non-sinusoidal synchronous machines

Sinusoidal motor's mathematical models are usually obtained using classical d–q transformation in the case of salient pole synchronous motors having sinusoidal field distribution. In this paper, a new inverse modelling for synchronous motors is presented. This modelling is derived from the properties of constant torque curves in the Concordia's reference frame. It takes into account the non-sinusoidal field distribution; EMF, self and mutual inductances having non-sinusoidal variations with respect to the angular rotor position. Both copper losses and torque ripples are minimized by adapted currents waveforms calculated from this model. Experimental evaluation was carried out on a DSP-controlled PMSM drive platform. Test results obtained demonstrate the effectiveness of the proposed method in reducing torque ripple.     

Generic Spectral Immittance Approach for Fast Design of Multilayered Bilateral Structures Including Anisotropic Media

In this letter, the spectral domain immittance-based approach is generalized for a fast and efficient design of bilateral microwave structures with multilayered anisotropic layers. This technique is based on the derivation of dyadic Green's functions by introducing, for the first time, a new conjoint admittance parameter. An original configuration based on three-line bilateral couplers is computed and validated using neural network models. Furthermore, numerical examples are presented and close agreement is obtained between simulated results and published data. The CPU time is also investigated     

Characterization of Two Nanofiltration Membranes for the Separation of Ions from Acid Mine Water

We evaluated nanofiltration for separation of ions from acid mine drainage (AMD), using two composite nanofiltration membranes (Nano-Pro-3012 and NF90) as examples of the polyamide class of acid-stable membranes. The structure of the NF membranes was characterized by scanning electron and atomic force microscopy. The NF90 displayed a higher permeate flux than Nano-Pro-3012, with higher relative roughness at both pH values. Both membranes suitably rejected most of the metals found in the AMD, but the Nano-Pro-3012 membrane proved unsuitable for sulphate removal.     

ZnS stacking order influence on the formation of Zn-poor and Zn-rich Cu2ZnSnS4 phase

This paper reports the synthesis and characterization of Cu₂ZnSnS₄ (CZTS) absorber films, prepared by a two-step electrodeposition of a ZnS (zinc sulfide) binary and a CZT (copper, zinc and tin) ternary precursors on Mo/Ti/Si substrates. The as-electrodeposited ZnS/CZT and CZT/ZnS stacks were thermally treated in a tubular furnace in sulfur environment at 550 °C. The role of the ZnS buffer layer is to provide a zinc and sulfur reservoir, needed to complete the formation of kesterite phase. X-ray diffraction and Raman analyses revealed the formation of the CZTS phase. The surface morphology and chemical composition of the films were studied using a scanning electron microscope. The bandgap values inferred from diffuse reflectance data, are discussed with respect to the stoichiometry which is considerably affected by the order of the stacks. Room-temperature photoluminescence of the CZT/ZnS sample showed a board PL band of 1.51 eV. It was found that the film with a ZnS layer on top is preferred for the formation of a Zn-rich single CZTS phase.

     

Laryngocele as an etiology of respiratory distress

Laryngocele is usually benign affection of the larynx. But serious forms of clinical emergency necessitating tracheotomy are possible. We reported 3 cases. New methods of treatment are presented endoscopic resection and laser marsupialization.     

Investigating the Effect of Process Parameter on the Properties of Rf Sputtered pSi Thin Film by Taguchi and ANOVA Analysis

Silicon - Boron doped pSi was deposited on Si substrate in the RF magnetron sputtering system by varying three process parameters, namely-sputtering power, working pressure, and Ar gas flow rate....     

The Effect of Defects on the Mobility of HEMT Transistors Based on AIGaN/GaN

A phenomenological low-filed mobility model is developed to describe the dependence ot the carrier molgmty on me gate to source bias applied for AIGaN/GaN high electron mobility transistor. The results show excellent agreement with experimental data, when compared thereby proving the validity of the model. In the proposed work the temporal evolution of the mobility degradation shows a sharp decline in emission rates below 456 s-1. We also note a sharp decline for large defects densities.