Research Integrity in Corrosion Research

Research Integrity is becoming increasingly important throughout the scientific community. Issues covered by this all-encompassing term can include good data management and security, use of appropriate research methodology, analysis of data based on sound theoretical foundations and correct use of statistics. Ethical issues such as publication authorship, intellectual property rights, conflict of interest and research misconduct including plagiarism, fabrication and falsification of data are also covered. One of the most significant types of research misconduct is that of scientific fraud. Many well-publicised cases have been reported over the years, most notably in the bioscience, and health/life science fields. Several historical examples are presented which illustrate the nature of such transgressions. A variety of causes have been identified, the misconduct most often being uncovered at a later stage after the findings have been disseminated. Surprisingly much of the research work conducted in some of these areas has proven difficult to replicate resulting in demands for a re-evaluation of all original data leading to the call for open access to all data (Open Science). Although few cases have been reported in the corrosion science area, it has not proven entirely immune from this problem. Some examples reported in the open literature in corrosion science and engineering are presented which illustrate that it is not immune to research misconduct. As scientists and engineers it behooves us to recognize that rigorous standards of ethical behaviour are always required in the conduct of research. However many of the pressures that corrosion researchers face are similar to those of other scientists, particularly research funding and career advancement. Sometimes this can compromise ethics concerning research in the field with damaging consequences to both the individual involved and the institution’s reputations. Sound experimental design with evidence of repeatability of results, high quality journal paper peer-review and editorial processes and verification practices and the need to carefully balance research/scientific needs versus those of industry and commercial enterprises are some of the most important issues of concern

Development of a Novel Humidity Sensor Based on a Polymer Silver Nanoparticle Composite

Humidity sensing is of particular concern for many industrial applications. Humidity sensors have typically been based on a reversible interaction between a polymer and water vapour. There is work published on gas sensors based on polymer gold nanoparticle composites, where the conductivity of the composite decreases on interaction with the gas. This happens because the swelling of the polymer which increases the electron hopping distance between the gold nanoparticles. The device in this work is a poly vinyl alcohol silver nanoparticle composite cast on an interdigital electrode array. On application of a dc bias, a current develops which is proportional to levels of humidity from 10% to 60%. The response is reversible and fast at room temperature. Details are provided of the synthesis, characterisation and use of the composite for humidity sensing. In addition the device forms the basis of a sensor for an array of gases

A Practical Photoelectrochemical Cell Using Nonprecious Metal Electrodes

Abstract: Photoelectrochemical cells (PECs) can be used to harvest light from the oxidation of dissolved organic matter. Similar to fuel cells but requiring light to operate, PECs contain a light assisted electrode that oxidises electron rich materials (anode); these electrons then flow to a typically Pt cathode where O2 is normally the electron acceptor. In this work a PEC cell containing inexpensive materials was shown to (a) mineralise typical organic compounds present in waste water and (b) produce electricity from their decomposition. The PEC cell consisted of a TiO2 coated conducting ink anode exposed to a light source, and an air electrode as cathode. Isopropyl alcohol (IPA) and formic acid were degraded using the PEC cell. It operates most efficiently with a 150 W Xe source but also degrades ascorbic acid using a tungsten light source and catechol using daylight. All compounds were shown to degrade by zero order kinetics, and the PEC cell was shown not to work appreciably in dark conditions. IPA photoelectrodegraded at a rate of 706 mol L-1 s-1, almost 200 times faster than ascorbic acid. Unconnected (photochemical) and blank cells where shown to degrade organic compounds to a much lesser extent than connected ones, showing that photoelectrodegradation was a more thorough mechanism for organic mineralisation than simple photodegradation or photochemical degradation. Using a standard household bulb as light source, a formic acid PEC cell produced 19.1 ± 2 mW m-2 , and when the same cell was placed on a laboratory window sill a power of 31.5 ± 2 mW m-2 was recorded. As the PEC cell prototype presented here utilises inexpensive materials, there is a possibility of scale up for outdoor and commercial use

Short Communication: a Simple Nanoparticle - based TiO2 Memristor Device and the Role of Defect Chemistry In Its Operation

A simple metal-semiconductor-metal device comprising TiO2 cast from a suspension of Degussa P25 and placed between two metal plates (Al/Al lap shears) demonstrated memristive-like resistive switching behaviour. A mechanism is proposed which relies upon the formation of p and n-type regions within the P25 semiconductor material ultimately leading to the formation of a p-n junction. This device also exhibited enhanced steady state currents upon the imposition of potential steps, most notably at higher potential magnitudes (both anodic and cathodic), indicating lack of ionic conduction

Characterization and Electrochromic Properties of Poly(2,3,5,6-Tetrafluoroaniline): Progress Towards a Transparent Conducting Polymer

Electrochromic films of poly(2,3,5,6-tetrafluoroaniline) (PTFA) were formed on ITO substrates from aqueous solutions utilising perchloric acid (HClO4) as dopant. Electrochemical and spectroscopic characterization of PTFA films was performed in background electrolyte and in solutions with the addition of tetrahydrofuran. When the PTFA film was removed from its growth medium, a significant decrease in the faradaic current was observed. The faradaic response increased on addition of tetrahydrofuran which facilitates ion movement through the polymer matrix. PTFA films deposited on ITO substrate were orange and light orange in the oxidized and reduced forms, respectively. The films were ca. 25 nm in thickness. In aqueous solution the films showed a porous structure with a non-uniform distribution of pore diameters. In the presence of tetrahydrofuran a less porous structure was observed

Formation of p-n Junctions in Nanoparticle Cerium Oxide Electrolytic Cells Displaying Memristive Switching Behaviour

A macro-scale metal–semiconductor–metal device comprising CeO2 nanoparticles cast from a suspension of cerium dioxide formed by a novel synthetic method was fabricated. Thin CeO2 films of 40 nm thickness placed between panels of aluminium and/or copper displayed memristive-like resistive switching behaviour upon the application of potential sweeps ranging between −0.6 V and 0.6 V. A mechanism is proposed based on the notion that an electrolytic cell operates under such conditions with the initial formation of p and n-type regions within the central semiconductive thin film. Evidence is presented for the existence of numerous point defects in these nanosized CeO2 films, which are also likely to play a role in the device\u27s operation acting as internal dopants. Steady currents were observed upon the imposition of constant potentials, most notably at higher potential values (both anodic and cathodic). It is suggested that electrons and holes act as charge carriers in these devices rather than ionic species as proposed in some other mechanisms

Eliminating electromechanical instability in dielectric elastomers by employing pre-stretch

Electromechanical instability (EMI) is one of most common failure modes for dielectric elastomers (DEs). It has been reported that pre-stretching a DE sample can suppress EMI due to strain stiffening taking place for larger strains and a higher elastic modulus are achieved at high stretch ratios when a voltage is applied to the material. In this work, the influence of equi-biaxial stretch on DE secant modulus was studied using VHB 4910 and silicone rubber (SR) composites containing barium titanate (BaTiO3, BT) particles and also dopamine coated BT (DP-BT) particles. The investigation of equi-biaxial deformation and EMI failure for VHB 4910 was undertaken by introducing a voltage-stretch function. The results showed that EMI was suppressed by equi-biaxial pre-stretch for all the DEs fabricated and tested. The stiffening properties of the DE materials were also studied with respect to the secant modulus. Furthermore, a voltage-induced strain of above 200% was achieved for the polyacrylate film by applying a pre-stretch ratio of 2.0 without EMI occurring. However, a maximum voltage-induced strain in the polyacrylate film of 78% was obtained by the SR/20 wt% DP-BT composite for a lower applied pre-stretch ratio of 1.6 and again EMI was eliminated

The Electrochemical Deposition of Zn-Mn Coating from Choline Choloride-urea Deep Eutectic Solvent

Electrochemical and microscopic techniques were used for characterization of Zn˗Mn coatings electrodeposited from choline chloride˗urea deep eutectic solvent. Cyclic voltammograms show that there was no discernible Mn reduction peak when only Mn2+ was present in DES solution. The distinct Mn peak developed only upon addition of Zn2+ to the solution, probably due to previous Zn nucleation on the steel substrate. It was found that 22-27 wt.% Mn, was deposited at current densities of 3-8 mA cm-2, amounts significantly higher than in aqueous electrolytes. Since higher deposition current densities resulted in the formation of a porous surface consisting of clusters of nodular crystallites, the optimal deposition c.d was determined to be 3 mA cm˗2

Analysis of copper(II) using the ascorbate/oxygen system – a valuable undergraduate resource

In deionised water, ascorbic acid (AH−), through oxidation by oxygen in the presence of copper(II), was found to degrade with zero-order kinetics. The magnitude of the reaction rate varied directly with the copper(II) concentration. At a higher pH (7.4), the same reaction was found to be pseudo-first order. Once again, the magnitude of the rate increased linearly with copper(II) concentration at a micromolar level. Dissolved oxygen levels, in excess AH− and trace copper(II), displayed similar kinetics under both conditions. Monitoring of either AH− levels or dissolved oxygen concentration was found to be a useful novel undergraduate practical laboratory for trace copper(II) determination. Students can measure the kinetics for standards and their unknown copper solution and quantitate the unknown copper

The Effect of Microstructure on the Dynamic Equi-Biaxial Fatigue Behaviour of Magnetorheological Elastomers

Dynamic equi-biaxial fatigue behaviour of isotropic and anisotropic magnetorheological elas-tomers (MREs) based on a silicone rubber matrix was investigated using the bubble inflation method. Con-stant engineering stress amplitude was used as the control mode and samples were fatigued over different stress ranges between 0.75MPa and 1.4MPa. S-N (Wöhler) curves showing plots of stress amplitude (σa) ver-sus cycles to failure (N) are presented. Stress-strain behaviour throughout the fatigue process is described. Elastic modulus (E*) was studied for the specific cycles measured. It was found that anisotropic MREs exhi-bited greater fatigue resistance than isotropic MREs for a given magnetic particle content. Stress softening and hysteresis continued throughout the tests though they were most pronounced in the first dozen cycles at the lower stress amplitudes. A limiting value of E*, below which fatigue failure is likely to take place was ob-served in both isotropic and anisotropic MREs, although the initial modulus was higher in anisotropic MREs