Adsorption and corrosion inhibition effect of 2-((5-mercapto-1,3,4-thiadiazol-2-ylimino)methyl)phenol Schiff base on mild steel

In this study, the inhibition effect of 2-((5-mercapto-1,3,4-thiadiazol-2-ylimino)methyl)phenol Schiff base (MTMP) on mild steel corrosion in 0.5 M HCl solution was studied. For this aim, electrochemical techniques such as potentiodynamic polarization curves, weight loss (WL), electrochemical impedance spectroscopy (EIS) and linear polarization resistance (LPR) were used. It was shown that, the MTMP Schiff base has remarkable inhibition efficiency on the corrosion of mild steel in 0.5 M HCl solution. Polarization measurements indicated that, the studied inhibitor acts as mixed type corrosion inhibitor with predominantly control of cathodic reaction. The inhibition efficiency depends on the concentration of inhibitor and reaches 97% at 1.0 mM MTMP. The remarkable inhibition efficiency of MTMP was discussed in terms of blocking of electrode surface by adsorption of inhibitor molecules through active centers. The adsorption of MTMP molecules on the mild steel surface obeys Langmuir adsorption isotherm.     

Diameter of titanium nanotubes influences anti-bacterial efficacy

Bacterial infection of in-dwelling medical devices is a growing problem that cannot be treated by traditional antibiotics due to the increasing prevalence of antimicrobial resistance and biofilm formation. Here, due to changes in surface parameters, it is proposed that bacterial adhesion can be prevented through nanosurface modifications of the medical device alone. Toward this goal, titanium was created to possess nanotubular surface topographies of highly controlled diameters of 20, 40, 60, or 80 nm, sometimes followed by heat treatment to control chemistry and crystallinity, through a novel anodization process. For the first time it was found that through the control of Ti surface parameters including chemistry, crystallinity, nanotube size, and hydrophilicity, significantly changed responses of both Staphylococcus epidermidis and Staphylococcus aureus (pathogens relevant for orthopaedic and other medical device related infections) were measured. Specifically, heat treatment of 80 nm diameter titanium tubes produced the most robust antimicrobial effect of all surface treatment parameters tested. This study provides the first step toward understanding the surface properties of nano-structured titanium that improve tissue growth (as has been previously observed with nanotubular titanium), while simultaneously reducing infection without the use of pharmaceutical drugs.     

A symmetric lattice-based wideband wide phase range digital phase shifter topology

In this paper, a novel digital phase shifter topology that achieves wideband and wide phase range is proposed. Wide frequency band operation is accomplished employing symmetrical all-pass lattice structures. Compact phase shifter size is obtained utilizing the miniaturized microwave monolithic integrated circuit (MMIC) design implementation technology. Therefore, resulting phase shifter units are suitable for various communication systems such as radar and cellular communication smart antenna arrays. This paper provides complete design equations together with design algorithm for the selected phase shift and the center frequency. Design algorithm is developed on MatLab environment. The proposed phase shifting circuit is implemented employing the commercially available 0.18-μm silicon CMOS technology. The new phase shifter topology provides 0⁰ to 360⁰ phase shift range over X-band, even beyond.     

The investigation of synergistic inhibition effect of rhodanine and iodide ion on the corrosion of copper in sulphuric acid solution

The synergistic inhibition effect of rhodanine (Rdn) and iodide ion on the corrosion of copper in 0.5 M H₂SO₄ solution was studied using electrochemical techniques. The surface morphologies of the substrates were examined by scanning electron microscopy (SEM). Elemental analysis of electrode surface exposed to test solution was determined by energy dispersive X-ray spectroscopy (EDX). It was found that Rdn provided satisfactory inhibition on the corrosion of copper. Moreover, its inhibition efficiency further increased in the presence of iodide ions due to synergistic effect. Finally, a mechanism of inhibition is proposed and discussed.     

Investigation of adsorption and corrosion inhibition effect of 1,1’-thiocarbonyldiimidazole on mild steel in hydrochloric acid solution

The adsorption and inhibition effect of 1,1′-thiocarbonyldiimidazole (TCDI) on the corrosion of mild steel (MS) in 0.5 M HCl solution was studied in both short and long immersion time (120 h) with the help of electrochemical impedance spectroscopy (EIS) and linear polarization resistance (LPR) techniques. For long-time tests, the hydrogen gas evolution (VH₂-t) and the change of open circuit potential with immersion time (E _ocp-t) were also utilized in addition to the former two techniques. The surface morphology of MS after its exposure to 0.5 M HCl solution with and without 1.0 × 10⁻² M TCDI was examined by scanning electron microscopy (SEM). It was demonstrated that the inhibition efficiency of studied inhibitor is concentration depended and increased with TCDI concentration. The higher value of inhibition efficiency was obtained after longer immersion time merely on the basis of strong increase of corrosion rate of mild steel in the blank solution. The high inhibition efficiency was discussed in terms of adsorption of inhibitor molecules and protective film formation on the mild steel surface which was substantiated by SEM micrographs. The adsorption of TCDI on MS was found to obey Langmuir adsorption isotherm.     

Prediction of the heat transfer performance of twisted tape inserts by using artificial neural networks

Journal of Mechanical Science and Technology - A numerical study is undertaken to investigate the effect of twisted tape inserts on heat transfer. Twisted tapes with various aspect ratios and...     

The Use of Vacuum Impregnation for Debittering Green Olives

The aim of this research was to assess the possibility of shortening the length of the debittering process for green table olive ‘Domat’ cultivar by vacuum impregnation (VI). For this purpose, debittering was carried out with NaCl (3 %), NaOH (1.5 %) and NaOH (1.5 %) + NaCl (3 %) solutions at atmospheric conditions and under vacuum (68 kPa). The effects of these applications on some physicochemical properties (total dry matter, total ash, titratable acidity, salt, protein, oil, oleuropein, total phenolics, antioxidant activity and colour) of the processed samples were determined. Total dry matter, titratable acidity, salt, protein and oil contents of the samples changed between 24.23 and 27.90, 0.22 and 0.45, 2.27 and 2.58, 0.50 and 1.26 and 6.79 and 9.42 % (w/w), respectively. Colour parameters (lightness (L*); redness (a*); yellowness (b*)) of the processed olives were measured as between 41.72 and 51.29, 15.09 and 13.30 and 22.79 and 34.84, respectively. Hue angles of the processed samples were changed between 59.78 and 68.52. VI was a useful tool for the shortening of the period of debittering process. Use of NaOH combined with NaCl in VI process caused the debittering period to decrease to 6 h. However, reduction of the amount of total phenolic compounds was the highest (21.43 %) in this condition. Use of alkali for debittering caused more dry matter diffusion from olive to the solution. There was no statistically significant difference between the oleuropein and total ash contents of the processed samples (p?<?0.01). Alkali treatment also caused more oil loss from the olives. Antioxidant activity of the samples reduced up to 59.89 %. This research was the first using VI for debittering of olives; further studies are necessary to optimise process conditions of debittering for limiting loss of natural antioxidants and other components and to ensure maximum benefits to the consumer.     

A review on microalgal growth stress parameters for sustainable biofuel production

Clean Technologies and Environmental Policy - Rapid growth and high carbon-fixation properties make microalgal biomass a preferred source of energy-production technologies, particularly biodiesel...     

Preparation of polyurethane/hectorite,polyurethane/montmorillonite,and polyurethane/laponite nanocomposites without organic modifiers

Polyurethane (PU) nanocomposites were prepared from hectorite (HEC) and laponite without adding any organic modifier. PU‐montmorillonite nanocomposites were prepared for comparison. The structure of the composites were investigated by transmission electron microscopy, X‐ray diffraction spectroscopy, and Fourier transform infrared spectroscopy. Thermal gravimetric analysis and dynamic mechanic analysis were used for determination of the thermal and viscoelastic behaviors, respectively. Tensile tests were conducted for characterization of the mechanical properties. The results showed a 113.5% increase in the tensile strength of PU containing 7 wt % HEC compared to that of neat PU. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010