[en] The aim of this work has been the study of the potential advantages of ursin a potentiostatic method in galvanizing industrial processes. The behaviour of cyanide-free alkaline zinc bath has been analyzed using the process cathodic efficiency as control parameter. By anodic re dissolution (Q₀x/Q_red measurement), the potential range of maximum cathodic efficiency has been set. Finally, the method has been scaled up to a semi-pilot plant in order to check the stability of the results and as a previous step to industry implementation. At this scale, the cathodic efficiency has been measured by weight loss tests. (Author) 22 refs

[en] Full text.The electrochemical behaviour of magnesium sacrificial anode (Mg) was investigated by means of potentiodynamic, potentiostatic techniques, completed by Evan's diagrams (under galvanic coupling conditions) and S.E.M. observations. Corrosion morphology of the anodes is related to the shape of the potentiodynamic polarization curves. Potentiostatic tests were carried out at different characteristic potential regions as defined by Pourbaix concept. Homogenous corrosion has been observed for the Mg anode and the roughness of the surface was related to hydrogen formation. The intentiostatic curves made it possible to evaluate the anodes efficiency as function of the current flow. The obtained Evan's diagrams are discussed taking into account the polarization effects at the electrodes for different experimental conditions

[en] Measuring the corrosion rate using a potentiostate equipment can be done by performing calibration on the device periodically. In addition, at each measurement of corrosion rate, measurements of Open Circuit Potential (OCP) are carried out by leaving the sample in solution for a certain of time until an equilibrium condition is reached (steady state). The calibration of potentiate equipment is successfully if the value of resistance approaches the dummy cell resistance value of 2000 ohms. The dummy cell has the resistance values of 1994 ∽ 2.006 ohms. The factors that effect of the OCP measurements result include calomel electrode condition, calomel filler solution and sample preparation technique. (author)

[en] Highlights: • Dual channel, dual working electrode ePAD has been developed and characterized. • Enables detection at two conditions in the same device using the same potentiostat. • Example application showing detection of norepinephrine and serotonin. -- Abstract: The simultaneous detection of multiple analytes from a single sample is a critical tool for the analysis of real world samples. However, this is challenging to accomplish in the field by current electroanalytical techniques, where tuning assay conditions towards a target analyte often results in poor selectivity and sensitivity for other species in the mixture. In this work, an electrochemical paper-based analytical device (ePAD) capable of performing simultaneous electrochemical experiments in different solution conditions on a single sample was developed for the first time. We refer to the system as a Janus-ePAD after the two-faced Greek god because of the ability of the device to perform electrochemistry on the same sample under differing solution conditions at the same time with a single potentiostat. In a Janus-ePAD, a sample wicks down two channels from a single inlet towards two discreet reagent zones that adjust solution conditions, such as pH, before flow termination in two electrochemical detection zones. These zones feature independent working electrodes and shared reference and counter electrodes, facilitating simultaneous detection of multiple species at each species’ optimal solution condition. The device utility and applicability are demonstrated through the simultaneous detection of two biologically relevant species (norepinephrine and serotonin) and a common enzymatic assay product (p-aminophenol) at two different solution pH conditions. Janus-ePADs show great promise as an inexpensive and broadly applicable platform which can reduce the complexity and/or number of steps required in multiplexed analysis, while also operating under the optimized conditions of each species present in a mixture.

[en] AlFeNi is one alternative cladding for future because of its advantages. In neutral and normal condition, corrosion rate of AlFeNi can be accepted. However as may be necessary to determine the corrosion rate at pH extremes as anticipatory measures to prevent reactor criticality. The method is used to characterize corrosion such as polarization resistance method and Tafel method using potensiostat. From the results obtained indicate that the pH used the pH 11,19; 12,41; 12,62 and 12,71 corrosion rate increases. For the method of polarization resistance corrosion rate values obtained for each pH are : 47,05 mpy; 437,467 mpy; 778,100 mpy; 933,367 mpy. Tafel method of corrosion rate were respectively : 47,003 mpy; 334,533 mpy; 632,633 mpy; 897,7 mpy. It can be concluded that with increasing pH of the medium in the corrosion test cell corrosion rate is greatly increased. (author)

[en] Highlights: • Reliable determination of progesterone (P4) in undiluted saliva with a disposable immunosensor. • Portable device/potentiostat constructed with commercial-off-the-shelf (COTS) components. • Fast (45 min) and sensitive determination of P4 using amperometry in stirred solutions or drops of quiescent solutions. • Determination of endogenous P4 in saliva with highly variable contents of the target hormone. -- Abstract: This paper describes the reliable determination of progesterone (P4) in undiluted saliva making use of a disposable amperometric immunosensors implemented on low-cost and portable device/potentiostat constructed with commercial-off-the-shelf (COTS) components. The immunosensor allows the fast (45 min), selective and sensitive determination (5 pg mL⁻¹ LOD) of P4 using amperometry in stirred solutions. The immunosensor was coupled to the COTS-based potentiostat and amperometry was made into drops of quiescent solutions. No significant differences were apparent between the analytical performance achieved with the immunosensor for P4 using both a conventional and the COST-based potentiostats. The practical applicability of the immunosensor coupled with the COTS-based potentiostat was demonstrated by determining the endogenous P4 content in different undiluted saliva samples with highly variable endogenous contents of the target hormone. The obtained results were in good agreement with those provided by the conventional ELISA methodology and with the contents reported in the literature for samples with similar characteristics. This validated the combined device for the reliable and minimally invasive determination of the target hormone involving a very simple protocol and taking only 45 min.

[en] Present article is devoted to potentiodynamic study of Al + 0.05% Sr alloy alloyed by magnesium in the medium of NaCl electrolyte. Influence of magnesium on electrochemical characteristics of Al + 0.05% Sr alloy in the medium of 3%, 0.3%, 0.03% NaCl electrolyte has been studied. Dependence of corrosion rate of Al + 0.05% Sr alloy on magnesium content in the medium of NaCl electrolyte has been considered.

[en] The Effect of Hydriding Temperature on the Corrosion Rate of Nuclear Reactor Structure Material Based on Zirconium Alloy and Stainless Steel. The material structure of a nuclear reactor will depend on the environment raised by radiation and high temperatures must be ensured its mechanical integrity. The purpose of this study was to study the effect of hydriding on the corrosion rate of fuel cladding and other structural materials based on zirconium alloys and stainless steels in demineral water solutions. Electrochemical corrosion tests are carried out at room temperature to eliminate high temperatures and stresses in the electrochemical process. In this research, the corrosion rate of zircaloy-2 which was hydriding at 150 ^oC and 500 ^oC was tested. The results showed that zircaloy-2 was easier to see corrosion compared to SS 304 and 316. Hydriding temperature of 500 ^oC can reduce energy corrosion potential in materials SS 304 and SS 316, the same thing also happened with zircaloy-2. It is undeniable that hydriding treatment plays a role in the corrosion characteristics of zircaloy-2, SS 304 and SS 316 cladding in demineral water, i.e the corrosion rate that occurs in zircaloy-2, SS 304 and SS 316 will increase with increasing hydriding temperature. (author)

[en] Designing with a Programmable System on a Chip (PSoC) allows for entire circuit designs to be implemented with a single commercially available chip and eliminates the need to physically assemble electronic components. This is possible as the PSoC incorporates a microcontroller with digital and analog components into a single package. While this design allows for much easier implementation of circuits, there are some drawbacks. In this paper we will demonstrate one of those drawbacks, high routing resistance in parts of the analog mesh that connects the analog parts and external pins. We show how this resistance can cause measurement errors when the PSoC is implemented as a single chip potentiostat. As the internal analog routing resistance is in the kΩ range, measuring currents in the Kॅ range can cause mV errors, leading to lose of voltage control during electrochemical experiments. We also demonstrate a calibration routine to compensate for this voltage error that reduced the error by over 90%. (paper)

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