Wyniki wyszukiwania - Biblioteka Nauki

1

The effect of SO3-Ph-BTBP on stainless steel corrosion in nitric acid

100%

Wilbraham R. J. , Boxall C.

Nukleonika

|

2015

|

tom Vol. 60, No. 4, part 2

865--869

EN

SO3-Ph-BTBP is a hydrophilic tetra-N-dentate ligand proposed for An(III)/Ln(III) separation by solvent extraction, and a candidate for use in future advanced reprocessing schemes such as GANEX and SANEX. We present the first study of the effect of SO3-Ph-BTBP on the corrosion behavior of stainless steels. Specifically, studies have been performed using steels and conditions equivalent to those found in relevant nuclear reprocessing flow sheets. SO3-Ph-BTBP has been shown to have little effect on either steel passivation or reductive dissolution. However, if driven cathodically into a region of hydrogen evolution at the electrode surface or conversely anodically into a region of transpassive dissolution, observed currents are reduced in the presence of SO3-Ph-BTBP, suggesting corrosion inhibition of the steel potentially through weak absorption of a SO3-Ph- -BTBP layer at the metal-solution interface. The lack of any observed corrosion acceleration via complexation of Fe3+ is surprising and has been suggested to be due to the slow extraction kinetics of SO3-Ph-BTBP as a result of a requirement for a trans- to cis-conformational change before binding.

2

Metoda wyznaczania przyrostu masy w procesie elektropolerowania

100%

Białostocka A. M. , Łukjaniuk A.

Zeszyty Naukowe Politechniki Białostockiej. Elektryka

|

2002

|

tom Z. 16

115-121

PL

W artykule przedstawiono metodę wyznaczania przyrostu masy miedzi podczas procesu galwanicznego pokrycia przedmiotów. W metodzie tej (pozwalającej na kontrolę przyrostu masy miedzi bez przerywania procesu galwanizacji) wykorzystuje się prawo Faraday'a - m=klt. Czas trwania procesu galwanizacji oraz wartość prądu mierzona jest przy pomocy uniwersalnego miernika elektrochemicznego EMU. Autorzy przeprowadzili analizę błędu wyznaczania masy przedstawioną metodą.

EN

In the article was presented the appoint method of the copper mass increasing during the galvanotechnic process of the objects. In the introducing method (gives the opportunity to control the mass increasing without the galvanotechnic process interrupting) were used the Faraday's law - m=klt. The duration time of the galvanotechnic process and value of the current tension were measured by the universal electrochemical tool EMU. The authors carried out the analysis of the error of the copper mass appoint the introducing method.

3

Electrical Properties of BaCeO₃-Based Electrolytes for use in Dual Protonic Ceramic-Solid Oxide Fuel Cells

100%

Gawel R. , Przybylski K.

Acta Physica Polonica A

|

2017

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tom 131

|

nr 5

1361-1366

EN

Bulk samples consisting of BaCe_{0.85}Y_{0.15}O_{3-δ} (BCY15) and Ce_{0.85}Y_{0.15}O_{2-δ} (YDC15) compounds, mixed together in different ratios, were studied as potential electrolytes in dual protonic ceramic-solid oxide fuel cells and compared with non-composite BCY15 and YDC15. The microstructures of the sintered materials indicate that BCY15 exhibits the largest grains, whereas composites have greater visible porosity than the non-composite samples. From X-ray diffraction studies it follows that BCY15 and YDC15 consist mainly of one phase, whereas the composites are two-phase materials. Electrochemical impedance spectroscopy studies at different temperatures show that the composite materials are capable of conduction the order of 10¯³ S/cm at temperatures above 500°C in a hydrogen-containing atmosphere. Furthermore, activation energy values of the conductivity determined for the composites in air atmosphere are between those obtained for BCY15 (E_{a}=0.590±0.017 eV) and YDC15 (E_{a}=1.132±0.008 eV). From this it follows that both phases of the composites influence the electrical conductivity of the materials. In conclusion, BCY15 and the BCY15-YDC15 composites show promise for future use as electrolytes in dual protonic ceramic-solid oxide fuel cells.

4

Fabrication of electrochemical nanoelectrode for sensor application Rusing focused ion beam technology

100%

Łaszcz A. , Nogala W. , Czerwinski A. , Ratajczak J. , Kątcki J.

Polish Journal of Chemical Technology

|

2014

|

tom Vol. 16, nr 3

40--44

EN

The capabilities and applications of the focused ion beam (FIB) technology for detection of an electrochemical signal in nanoscale area are shown. The FIB system, enabling continuous micro- and nanofabrication within only one equipment unit, was used to produce a prototype of electrochemical nanometer-sized electrode for sensor application. Voltammetric study of electrochemically active compound (ferrocenemethanol) revealed the diffusion limiting current (12 pA), corresponding to a disc (planar) nanoelectrode with about 70 nm diameter of contact area. This size is in a good accordance with the designed contact-area (50 nm × 100 nm for width × thickness) of the FIB-produced nanoelectrode. It confi rms that produced nanoelectrode is working properly in liquid solution and may enable correct measurements in nanometer-sized regions.

5

Badania Ludwika Brunera z elektrochemii

100%

Dolecki M.

Kwartalnik Historii Nauki i Techniki

|

2007

|

tom R. 52, nr 3/4

165-184

EN

The present article is showing the most significant findings concerning electrochemistry of the Cracow's scholar - Ludwik Bruner. Electrochemistry was the second and main - after chemical kinetics - field of research work of the scientist. Bruner usually together with his co-workers and students - used to take up his scientific research on electroche- mistry both of hydrous and anhydrous solutions. During his stay in Karlsruhe in 1903, he took up searches on Jacques cell together with Fritz Haber. The researchers revealed that Jacques cell is in fact fuel cell. Bruner's kinetic searches on the reaction of bromination of toluene in nitrobenzene made him start works over electrochemistry of non - aqueous solutions and, in particular, over halogens and interhalogen compounds in solutions (mainly in nitrobenzeneanj in liquid SO:), and halogens in solutions and in liquid state. As far as the solutions ol halogens and interhalogen compounds are concerned, Bruner did not state any existena of halogen cations. Moreover, the Cracow's scholar pointed out, among others, thenen value of electrochemical potential of ions S2\ Late in life Bruner was interested inelec trochemistry of aqueous solutions of non - metal hydrides - H2Se and H2Te.

6

Fabrication of Electrochemical Nanoelectrode for Sensor Application Using Focused Ion Beam Technology

100%

Łaszcz A. , Nogala W. , Czerwinski A. , Ratajczak J. , Kątcki J.

Polish Journal of Chemical Technology

|

2014

|

tom 16

|

nr 3

40-44

EN

The capabilities and applications of the focused ion beam (FIB) technology for detection of an electrochemical signal in nanoscale area are shown. The FIB system, enabling continuous micro- and nanofabrication within only one equipment unit, was used to produce a prototype of electrochemical nanometer-sized electrode for sensor application. Voltammetric study of electrochemically active compound (ferrocenemethanol) revealed the diffusion limiting current (12 pA), corresponding to a disc (planar) nanoelectrode with about 70 nm diameter of contact area. This size is in a good accordance with the designed contact-area (50 nm × 100 nm for width × thickness) of the FIB-produced nanoelectrode. It confirms that produced nanoelectrode is working properly in liquid solution and may enable correct measurements in nanometer-sized regions.

7

Niskotemperaturowe ciecze jonowe - ciekawostka laboratoryjna czy zapowiedź rewolucji technologicznej? Cz. 3 Zastosowanie w procesach elektrochemicznych

100%

Kosmulski M. , Saneluta C. , Marczewska-Boczkowska K.

Przemysł Chemiczny

|

2002

|

tom T. 81, nr 4

234-236

8

Magnetic nanowires (Fe, Fe-Co, Fe-Ni) : magnetic moment reorientation in respect of wires composition

100%

Kalska-Szostko B. , Wykowska U. , Satuła D.

Nukleonika

|

2015

|

tom Vol. 60, No. 1

63--67

EN

Magnetic nanowires of Fe, Fe-Co, and Fe-Ni alloy and layered structure were prepared by electrochemical alternating current (AC) deposition method. The morphology of the nanowires in and without the matrix was studied by energy dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM), and X-ray diffraction (XRD), respectively. The wires either show strong dependence on the combination of elements deposition (alloy or layered) or chemical composition (Co or Ni). The magnetic properties of the nanostructures were determined on the basis of Mössbauer spectroscopy (MS).

9

The effect of SO3-Ph-BTBP on stainless steel corrosion in nitric acid

100%

Wilbraham R. J. , Boxall C.

Nukleonika

|

2015

|

tom 60

|

nr 4

865-869

EN

SO3-Ph-BTBP is a hydrophilic tetra-N-dentate ligand proposed for An(III)/Ln(III) separation by solvent extraction, and a candidate for use in future advanced reprocessing schemes such as GANEX and SANEX. We present the first study of the effect of SO3-Ph-BTBP on the corrosion behavior of stainless steels. Specifically, studies have been performed using steels and conditions equivalent to those found in relevant nuclear reprocessing flow sheets. SO3-Ph-BTBP has been shown to have little effect on either steel passivation or reductive dissolution. However, if driven cathodically into a region of hydrogen evolution at the electrode surface or conversely anodically into a region of transpassive dissolution, observed currents are reduced in the presence of SO3-Ph-BTBP, suggesting corrosion inhibition of the steel potentially through weak absorption of a SO3-Ph-BTBP layer at the metal-solution interface. The lack of any observed corrosion acceleration via complexation of Fe3+ is surprising and has been suggested to be due to the slow extraction kinetics of SO3-Ph-BTBP as a result of a requirement for a trans- to cis-conformational change before binding.

10

Magnetic nanowires (Fe, Fe-Co, Fe-Ni) – magnetic moment reorientation in respect of wires composition

100%

Kalska-Szostko B. , Wykowska U. , Satuła D.

Nukleonika

|

2015

|

tom 60

|

nr 1

63-67

EN

Magnetic nanowires of Fe, Fe-Co, and Fe-Ni alloy and layered structure were prepared by electrochemical alternating current (AC) deposition method. The morphology of the nanowires in and without the matrix was studied by energy dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM), and X-ray diffraction (XRD), respectively. The wires either show strong dependence on the combination of elements deposition (alloy or layered) or chemical composition (Co or Ni). The magnetic properties of the nanostructures were determined on the basis of Mössbauer spectroscopy (MS).

11

Development of an electrochemical method for the measurement of antioxidant capacity of pure compounds and natural substances extracts

100%

Lanez T. , Rebiai A.

International Letters of Chemistry, Physics and Astronomy

|

2013

|

tom Vol. 1

46-54

EN

A new method has been developed to measure total antioxidant activity of antioxidants in foods and natural substances without use of standard antioxidants and without use of calibration curves plotting. It is based on measuring the oxidation peak current of superoxide anion radical electrochemically generated by reduction of commercial molecular oxygen in dimethylformamide. The method has been validated using 7 known standard antioxidants and the results have been compared with those obtained by the DPPH and molybdate ion reduction assays. Measured antioxidant capacities were highly correlated with those obtained using DPPH (r2 = 0.549) and molybdate ion reduction assay (r2 = 0.434).

12

An assessment of cleaning mechanisms driven by power ultrasound using electrochemistry and highspeed imaging techniques

100%

Offin D. , Vian C. , Birkin P. , Leighton T.

Hydroacoustics

|

2008

|

tom Vol. 11

299-312

EN

The cleaning of a surface is monitored in real time using a number of physical measurements. In particular an electrochemically inactive material is removed from an electrode while the electrode is able to detect a redox system in the bulk liquid. The removal of the material from the surface is monitored as an increased Faradaic current at the electrode surface. This signal is used to assess the ability of the cleaning method employed, in this case the application of power ultrasound to the system, as a function of the position of the electrode with respect to the sound source. It is shown that, depending on the conditions employed, surface cleaning is driven by different mechanisms. In order to validate these findings highspeed imaging of the system was undertaken and the results correlated with the electrochemical data. In addition a number of novel electrodes were also employed to assess the cleaning efficiency as a function of the electrode geometry employed. Implications for surface cleaning in the presence of power ultrasound are suggested.

13

Mechanical, corrosion-mechanical and electrochemical parameters sensitive to corrosion-hydrogen degradation of structural steels under long - term in-service conditions

88%

Nykryforchyn H.

Advances in Materials Science

|

2007

|

tom Vol. 7, nr 1(11)

176-183

EN

Some low-alloyed steels exploited for decades of years in corrosion-hydrogen environments, namely, power steam pipeline, reactor shell of oil hydrocracking, oil trunk pipeline, are considered. The essential decrease of mechanical (impact strength, creep), corrosion (corrosion rate) and corrosion-mechanical (stress corrosion cracking) properties of exploited metal to compare with that in the virgin state is demonstrated. Especially high sensitivity of fracture mechanics characteristics (effective range of stress intensity factor of fatigue crack growth [detlaKth eff], fracture toughness Jlc) to in-service degradation is shown. It is revealed that same electrochemical parameters (polarization resistance, corrosion current) are especially sensitive to in-service degradation of steels at high and low temperatures as well. A correlation between changes of electrochemical and mechanical properties in the steel degradation process is drawn up.

14

Electrochemical Behaviour of Chloride and Bromide Complexes of Palladium(II) with 4-Amino-6-methyl-3-thio-3,4-dihydro-1,2,4-triazin-5(2H)-one in Dimethylformamide at Glassy Carbon Electrode

88%

Fotouhi L. , Ghassemzadeh M. , Heravi M. M.

Polish Journal of Chemistry

|

2003

|

tom Vol. 77 / nr 7

895-902

EN

The electrochemical behaviour of palladium(II) complexes of PdCl2L(I) and PdBr2L(II) (L = 4-amino-6-methyl-3-thio-3,4-dihydro-1,2,4-triazin-5(2H)-one) has been investigated in dimethylformamide at glassy carbon electrode. Under cyclic voltammetric conditions, complex PdCl2L is found to undergo a one-electron oxidation at 1.27 V with a prewave, which is similar to oxidation of ligand L. The oxidation of ligand shows an oxidation wave at 1.25 V with EC mechanism. In the chemical reaction following the one electron irreversible oxidation of ligand, the electrochemical-generated cation radical forms a dimer, which is reduced at reverse scan at -0.66 V to reproduce the monomer. Thus, the nature of oxidation of both complexes I and II suggests a ligand-centered oxidation, because their oxidation behaviour is similar to oxidation of ligand L. However, the reduction of both complexes I and II shows a reduction peak at -1.31 V and -1.33 V respectively, which is related to reduction of metal center of complexes, Pd (II) to Pd (I).

15

Influence of plastic deformation on electrochemical properties of X5CrNi18-10 steel

88%

Rejmer W.

Technical Sciences / University of Warmia and Mazury in Olsztyn

|

2020

|

tom nr 23(3)

253--262

EN

The purpose of this study was to determine the effect of plastic deformation on the electrochemical properties of X5CrNi18-10 steel. The tested material belongs to the group of stainless steels with low carbon content, and it is used in many industries due to its high corrosion resistance. In most applications of the tested material, it is formed into complicated shapes and exposed to aggressive environments. Examples include the applications in medicine (implants) as well as in civil engineering and nuclear power plants. Different effects of deformation on anti-corrosion properties have been described in the literature. Samples with 5 different deformations were obtained in the present experiment. Electrochemical direct electrical current and alternating electrical current tests were performed for the obtained materials. The tests were carried out in a 1 molar sodium chloride solution. The study revealed an increase in the corrosion resistance of samples with increasing strain in the tested strain ranges.

16

Tribologiczne i elektrochemiczne procesy w systemach tribologicznych

88%

Kosmynina M. , Kosmynin A.

Problemy Eksploatacji

|

2000

|

tom nr 3

97-110

PL

W pracy uzasadniono celowość podjęcia badań powiązań pomiędzy zjawiskami w procesach tribologicznych i elektrochemicznych. Te dwa rodzaje procesów łączy występowanie przemian fazowych na granicy rozdziału faz element/środowisko. Przeniesienie ładunku elektrycznego i masy pomiędzy współpracującymi elementami zależy od rodzaju materiału tych elementów, składu chemicznego środowiska ich współoddziaływania oraz napięcia zewnętrznego pomiędzy tymi elementami. W zależności od odległości pomiędzy elektrodami [przy niezmiennych pozostałych parametrach układu] mogą występować bardzo zróżnicowane efekty w zjawiskach powierzchniowych współpracujących elementów. Wykazano wpływ rodzaju ruchu względnego elementów na procesy triboelektrolityczne. Ruch ślizgowo-obrotowy intensyfikuje proces elektro-redukcji miedzi w zakresie elektrochemicznej kinetyki. Ruch posuwisto-zwrotny zawęża zakres wydzielenia miedzi, odpowiadający procesom elektrochemicznej kinetyki. Dla procesów anodowego rozpuszczania zwiększenie prędkości przesuwu elementów względem siebie w układzie triboelektrolitycznym zwiększa prędkość aktywnego rozpuszczania w stanie pasywacji elementu. Dla zmniejszenia zużycia elementów w układach triboelektrolitycznych korzystnym jest stosowanie katodowej polaryzacji zewnętrznej przy wprowadzeniu do elektrolitu jonów wydzielanego metalu.

EN

In the work was motive that it is worth to examine connections between phenomena in electrochemical and tribological processes. These two kind of processes are connected with each other by having phase changes on the phase division boundary element/environment. Electric charge transition and the mass between co-operating elements depends on material kind of these elements, their environment chemical composition where they co-operate and outer voltage between these elements. Depending on electrode distance (at other steady system parameters) varied effects can relative motion element kind on tribological processes, sliding - rotational motion intensifies copper electro reduction process in the range of electrochemical kinetics. Plane - returnable motion decreases the range of copper emission meeting the kinetics electrochemical processes. For anode dissolution processes shift speed increase in relation to each other in triboelectrolytic system increases the speed of active dissolution during element passivation. To decrease the element usage in tribological system it is advisable to use cathode outer polarization when metal emission ions are incorporated into the electrolyte.

17

An Application of Graphical Numerical Accelerators in Simulations of Ion-Transport Through Biological Membranes

88%

Górecki A.

Computational Methods in Science and Technology

|

2013

|

tom Vol. 19, No. 1

33--46

EN

The modeling of ion-transport through biological membranes is important for understanding many life processes. The transmembrane potential and ion concentrations in the stationary state can be measured in in-vivo experiments. They can also be simulated within membrane models. Here we consider a basic model of ion transport that describes the time evolution of ion concentrations and potentials through a set of nonlinear ordinary differential equations. To reduce the computation time I have developed an application for simulation of the ion-flows through a membrane starting from an ensemble of initial conditions, optimized for a Graphical Processing Unit (GPU). The application has been designed for the CUDA (Compute Unified Device Architecture) technology. It is written in CUDA C programming language and runs on NVIDIA TESLA family of numerical accelerators. The calculation speed can be increased almost 1000 times compared with a sequential program running on the Central Processing Unit (CPU) of a typical PC.

18

Voltametric Behavior of the Nitro Radical Anion Generated Electrochemically from Furazolidone at Glassy Carbon Electrode

88%

Fotouhi L. , Kiapasha L.

Polish Journal of Chemistry

|

2004

|

tom Vol.78 /nr 11-12

2175-2184

EN

The electrochemical behavior of the nitro radical anion resulted from the reduction of furazolidone has been studied in mixed aqueous-dimethylformamide (DMF) solvent at glassy carbon electrode (GCE) by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). Furazolidone is reduced in two cathodic steps in the low concentration of DMF and acidic media, giving hydroxylamine and amine derivatives via reduction by four and two electrons, respectively. The addition of DMF to the basic buffer solution enables the presence of two different reduction processes to be established. The first cathodic peak is related to a 1e-reversible reduction process corresponding to the formation of nitro anion radical (RNO2 Ĺ ) and the more negative peak is due to the formation of hydroxylamine via a 3e-irreversible reduction process. The cyclic voltammetry technique has been employed to the study of RNO2/RNO2 Ĺ couple. The reversibility of radical anion is investigated by the ratio of anodic to cathodic current, Ia1/Ic1, by increasing DMF content and pH. The influence of scan rate on the Ia1/Ic1 ratio shows an ECi mechanism, in which this subsequent chemical reaction corresponds to protonation reaction ofRNO2 Ĺ that is initiated electrochemically. The effect of cationic and anionic surfactants has been reported on the electrochemical behavior of furazolidone.

19

Synthesis, Characterization and Electrochemistry of New Type Soluble Porphyrazine Containing 3-Phenylpropylthio Substituent

88%

Erdogmus A. , Koca A. , Avciata U. , Gül A.

Polish Journal of Chemistry

|

2008

|

tom Vol. 82, nr 8

1541-1541

EN

Octakis(3-phenylpropylthio) porphyrazines MPz(SR)8, where (M = Mg, H, Ni, Zn, Co) and R = C9H11, were synthesized starting with the corresponding unsaturated dicarbonitrile derivative. These new compounds have been investigated and characterized by UV, FT-IR, 1H NMR, GC-MS and elemental analysis methods. As in the case of the unmetalated species, [H2Pz], three reversible one-electron reductions and one reversible oxidation process (two for Co(II)Pz) were observed for all of the metal complexes. The E1/2 values are similar for the H2Pz, Ni(II)Pz and Zn(II)Pz derivatives with negative shift due to the different effective charges of the central metal ion. Peak to peak separations and separation between the first reduction and first oxidation couples related with the HOMO-LUMO gap of the complexes are in harmony with the common porphyrazine complexes.

20

Elektrochemiczne zachowanie wielościennych nanorurek węglowych modyfikowanych amoniakiem

75%

Walczyk M. , Biniak S.

Inżynieria i Ochrona Środowiska

|

2013

|

tom T. 16, nr 2

235--243

PL

Niemodyfikowane oraz utlenione wielościenne nanorurki węglowe (MWCNT) poddane zostały wygrzewaniu w temperaturze 500 oraz 900°C w strumieniu amoniaku. Wykonano badania fizykochemiczne, mające na celu ocenę jakościową efektów modyfikacji. Ponadto badano zachowanie elektrochemiczne uzyskanych materiałów węglowych metodą trójelektrodowej cyklowoltamperometrii w środowisku niewodnym, gdzie elektrodą pracującą była sedymentacyjna warstwa nanorurek węglowych. Wykazano, że azot wiąże się trwale z powierzchnią nanorurek, gdy wygrzewaniu w strumieniu amoniaku w temperaturze 500°C poddano wielościenne nanorurki wstępnie utlenione. Atomy azotu najprawdopodobniej wiążą się z powierzchnią w postaci soli amoniowych oraz amidów o różnej rzędowości. W tych warunkach prawdopodobnie część azotu jest wbudowana w struktury aromatyczne (aromatyczne heterocykliczne, azo-aromatyczne).

EN

Unmodified and oxidized multi walled carbon nanotubes (MWCNT) were heated (500°C and 900°C) in a stream of ammonia. The characteristics of the physicochemical properties of the samples obtained were estimated using various experimental methods. Cyclic voltammetry studies of nano-carbon electrodes in non-aqueous electrolyte were carried out to evaluate the electrochemical behavior of modified MWCNTs. The results of this work conclusively demonstrate the generation of nitrogen-containing moieties on the MWCNT surface only in case of heating at 500°C in a stream of ammonia previously oxidized carbon nanotubes. Probably the nitrogen atoms were bound to the nanotubes surface as ammonium salts, amides with different order of a nitrogen atom and aromatic structures (aromatic heterocyclic, azo-aromatic).