Search results for "Dielectric Spectroscopy"

INVESTIGATIONS OF THE INFLUENCE OF DIFFERENT ADDITIVES TO THE LANTHANUM RICH MISCHMETAL

2007

EQCM and EIS studies of Znaq2++2e−⇄Zn0 electrochemical reaction in moderated acid medium

2003

The zinc electrodissolution and electrodeposition have been studied by means of electrochemical quartz crystal microbalance and electrochemical impedance spectroscopy. Relevant information on the mechanism of these electrochemical processes is provided by the analysis of experimental data. The zinc electrodeposition takes place with an important participation of hydrogen ions while the zinc electrodissolution occurs, in these experimental conditions, by a mechanism in two steps. Besides, it is proved that the presence of molecular oxygen in the solution contributes to the formation of a passive layer on the metallic zinc deposit.

Tumour tissue monitoring during photodynamic and hyperthermic treatment using bioimpedance spectroscopy.

2003

Electrical bioimpedance spectroscopy is a fast and relatively easily applicable method for tissue characterization. In the frequency range up to 10 MHz, current conduction through tissue is mainly determined by tissue structure, i.e. the extra- and intra-cellular compartments and the insulating cell membranes. Therefore, changes in the extra- and intra-cellular fluid volumes are reflected in the impedance spectra. Investigations of tumours (DS sarcoma, implanted on the hind foot dorsum of rats) during treatment with localized hyperthermia (HT), photodynamic therapy (PDT) and the combination of these two components were carried out using impedance spectroscopy in the frequency range of 37 Hz…

Photoelectrocatalyzed degradation of organophosphorus pesticide fenamiphos using WO3 nanorods as photoanode

2020

[EN] In this study, WO3 nanostructures were synthesized by the electrochemical anodization technique to use them on the degradation of persistent organic compounds such as the pesticide fenamiphos. The acids electrolyte used during the anodization were two different: 1.5 M H2SO4-0.05 M H2O2 and 1.5 M CH4O3S-0.05 M H2O2. Once the samples have been manufactured, they have been subjected to different tests to analyze the properties of the nanostructures. With Field Emission Scanning Electron Microscopy (FESEM) the samples have been examined morphologically, their composition and crystallinity has been studied through Raman Spectroscopy and their photoelectrochemical behaviour by Photoelectroch…

Redox tuning and species distribution in Maya Blue-type materials: a reassessment.

2013

Maya Blue-type specimens prepared from indigo (1 wt %) plus kaolinite, montmorillonite, palygorskite, sepiolite, and silicalite are studied. Liquid chromatography with diode array detection, ultra-performance liquid chromatography coupled with mass spectrometry, and pyrolysis-silylation gas chromatography-mass spectrometry analyses of the extracts from these specimens combined with spectral and solid-state voltammetry, electrochemical impedance spectroscopy, and scanning electrochemical microscopy techniques provide evidence for the presence of a significant amount of dehydroindigo and isatin accompanying indigo and other minority organic compounds in all samples. Solid-state electrochemist…

Towards a deeper understanding of the inhibition mechanism of a new 1,2,3-triazole derivative for mild steel corrosion in the hydrochloric acid solut…

2020

Abstract The corrosion inhibition effect of a new synthesized heterocycle 1,2,3-triazole, namely(1-p-tolyl-1H-1,2,3-triazol-4-yl) methanol (TTM) was studied in 1 M hydrochloric acid solution by using both experimental and theoretical techniques. The inhibitory action of the TTM was investigated by potentiodynamic polarization (PDP) at various temperatures (298–333 K). PDP experiments revealed that the TTM behaved as mixed type inhibitor by decreasing both anodic and cathodic corrosion densities. Electrochemical impedance spectroscopy (EIS) measurements confirmed that the studied inhibitor can suppress mild steel corrosion effectively in acidic solution with an inhibition efficiency of 90% a…

Electrochemical Impedance Spectroscopy Study of the Behaviour of Lanthanide-Rich Films Formed on Aluminium-Magnesium Alloys

1998

The film covering formed on AA5083 aluminium-magnesium alloy by immersion treatments in solutions containing CeCl 3 has been characterized by means of electrochemical techniques. The measurement of linear polarization has enabled to establish that the treatments applied provide efficient protection against both uniform and pitting corrosion of alloy AA5083, used in shipbuilding, in solutions of NaCl. This study has been focused on the use of Electrochemical Impedance Spectroscopy as a characterization technique for these film coverings.

Junction Dynamics in Telechelic Hydrogen Bonded Polyisobutylene Networks

1996

4-Urazoylbenzoic acid groups are attached to the chain ends of polyisobutylene. The cooperative assembling process of these polar groups is studied by DSC and dielectric and dynamic mechanical spectroscopy. The melting of the ordered clusters occurs in the temperature range 380-390 K. Distortions within the U4A clusters (Σ process) are monitored below the melting temperature T m with dielectric spectroscopy. On a larger length scale, these distortions also lead to stress relaxation which can be probed by dynamic mechanical measurements. Near T m , the relaxation ofU4A multiplets (α* relaxation) is detected with dielectric spectroscopy. In this temperature range, dynamic mechanical measureme…

Dispersion and Stabilization of Exfoliated Graphene in Ionic Liquids.

2019

The liquid-phase exfoliation of graphite is one of the most promising methods to increase production and commercial availability of graphene. Because ionic liquids can be easily obtained with chosen molecular structures and tuneable physicochemical properties, they can be use as media to optimise the exfoliation of graphite. The under- standing of the interactions involved between graphite and various chemical functions in the solvent ions will be helpful to find liquids capable of dissociating and stabilising im- portant quantities of large graphene layers. After a step of sonication, as a mechanical precursor, samples of suspended exfoliated graphene in different ionic liquids have been c…

Dielectric spectroscopy as a potential technique for prediction of kiwifruit quality indices during storage

2019

Dielectric spectroscopy has been employed as a simple, low cost and a non-destructive way for prediction of some physicochemical indices of kiwifruit during storage. A parallel-plate capacitor was developed and supplied with sinusoidal voltage waves within a frequency range of 40 kHz – 20 MHz. Dielectric properties of samples were measured by the dielectric sensor. Additionally, changes associated with fruit ripening properties, including firmness, total soluble solid (TSS) and pH were determined as a function of time at 2 °C. The results showed that storage time significantly affected the quality characteristics of kiwifruit. Artificial neural networks (ANNs) were employed to develop model…