Informacja

Drogi użytkowniku, aplikacja do prawidłowego działania wymaga obsługi JavaScript. Proszę włącz obsługę JavaScript w Twojej przeglądarce.

Wyszukujesz frazę "Cobalt" wg kryterium: Temat


Tytuł:
Valorization of Cobalt from Waste LIB Cathode through Cobalt Oxalate and Cobalt Oxide Synthesis by Leaching-Solvent Extract-Precipitation Stripping
Autorzy:
Swain, B.
Lee, J.-C.
Lee, C.-G.
Powiązania:
https://bibliotekanauki.pl/articles/352333.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
valorization of cobalt
cobalt oxide powder
rod-shaped cobalt oxalate
precipitation stripping
Opis:
An ecoefficient, economical and sustainable valorization process for the synthesis of Co3O4 from waste lithium-ion battery (LIB) by leaching-solvent extract-scrubbing-precipitation stripping route has been developed. Through an optimization, the waste LIB cathode was leached using 2000 mole/m3 of H2SO4 and 5 Vol. % of the H2O2 at a pulp density of 100 kg/m3 under leaching time 60 minutes and temperature 75°C. From the separated leach liquor, cobalt was purified by saponified Cyanex 272. From cobalt, loaded Cyanex 272 impurities were scrubbed and the CoC2O4·2H2O was recovered through precipitation stripping. Finally, the precipitate was calcined to synthesize Co3O4, which is a precursor for LIB cathode materials manufacturing. From TGA-DTA, followed by XRD analysis it was confirmed that at 200°C the CoC2O4·2H2O can be converted to anhydrous CoC2O4 and at 350°C the anhydrous can be converted to Co3O4 and at 1100°C the Co3O4 can be converted to CoO. Through reported route waste LIB can back to LIB manufacturing process through a versatile and flexible industrial approach.
Źródło:
Archives of Metallurgy and Materials; 2018, 63, 2; 1037-1042
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ca-Modified Co/SBA-15 Catalysts for Hydrogen Production through Ethanol Steam Reforming
Autorzy:
Chiou, J. Y. Z.
Liu, S. W.
Ho, K. F.
Huang, H. H.
Tang, Ch. W.
Wang, Ch. B.
Powiązania:
https://bibliotekanauki.pl/articles/411682.pdf
Data publikacji:
2014
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
cobalt catalysts
ethanol
steam reforming
Opis:
Hydrogen production through steam reforming of ethanol (SRE) over the Ca-modified Co/SBA-15 catalysts was studied herein to evaluate the catalytic activity, stability andthebehavior of coke deposition.The Ca-modified SBA-15 supports were prepared from the Ca(NO3)2•4H2O (10 wt%) which was incorporated to SBA-15 by incipient wetness impregnation (assigned as Ca/SBA-15) and direct hydrothermal (assigned as Ca-SBA-15) method. The active cobalt species from the Co(NO3)2•6H2O (10 wt%) was loaded to SiO2, SBA-15 and modified-SBA-15 supports with incipient wetness impregnation method to obtain the cobalt catalysts (named as Co/SiO2, Co/SBA-15, Co-Ca/SBA-15 and Co/Ca-SBA-15, respectively). The prepared catalysts were characterized by using X-ray diffraction (XRD), temperature programmed reduction (TPR), transmission electron microscopy (TEM) and BET.The catalytic performance of the SRE reaction was evaluated in a fixed-bed reactor.The results indicated that the Co/Ca-SBA-15 catalystwas preferential among these catalysts and the ethanol can be converted completely at 375 °C. The hydrogen yield (YH2) approached 4.76 at 500 °C and less coke deposited. Further, the long-term stabilitytest of this catalyst approached100h at 500 °C and did not deactivate.
Źródło:
International Letters of Chemistry, Physics and Astronomy; 2014, 5; 1-16
2299-3843
Pojawia się w:
International Letters of Chemistry, Physics and Astronomy
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Anodowe roztwarzanie kobaltu w roztworach metanolowych z niską zawartością wody
Anodic Dissolution of Cobalt in Solutions of Methanol with Low Water Content
Autorzy:
Waliczek, A.
Starowicz, M.
Powiązania:
https://bibliotekanauki.pl/articles/382825.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
kobalt
roztwór metanolowy
roztwarzanie anodowe
związek kobaltu
cobalt
methanol solution
anodic dissolution
cobalt compound
Opis:
Prezentowana praca przedstawia elektrochemiczne badania kobaltu w bezwodnym metanolowym roztworze LiCl, oraz w roztworach zawierających odpowiednio 1, 3 i 5 % wody. Krzywe polaryzacyjne kobaltu, we wszystkich badanych środowiskach mają podobny kształt z jednym pikiem anodowym. Stężenie wody nie ma istotnego wpływu na sam proces anodowego roztwarzania. Podczas chronoamperometrycznej polaryzacji kobaltu zarówno w roztworze bezwodnym jak i roztworach zawierających wodę otrzymano koloidalne roztwory związków kobaltu. Otrzymane koloidy były analizowane przy pomocy spektroskopii w świetle widzialnym i nadfiolecie (UV-VIS) oraz spektroskopii w podczerwieni (FTIR). Badania spektroskopowe wykazały istotny wpływ wody na produkty anodowego roztwarzania kobaltu w roztworach metanolowych. Zaobserwowano również, że cząsteczki alkoholu silnie adsorbują się na powierzchni otrzymanych związków kobaltu, co utrudnia identyfikację produktu końcowego. Celem pracy jest anodowe roztwarzanie kobaltu stosując metanol jako rozpuszczalnik.
This work presents electrochemical investigations of cobalt in unhydrous methanol solution of LiCl and in the corresponding solutions containing 1, 3, and 5 % of water. The curves for cobalt polarisation in all the investigated environments have similar shape with a single anodic peak. Water concentration does not influence considerably the proces of anodic dissolution. Colloidal solutions of cobalt compounds were obtained during chronoamperommetric polarisation of cobalt both in unhydrous solution and in the solutions containing water. The resulting solutions were analysed by means of ultraviolet and visible light spectroscopy (UVVIS) and infrared spectroscopy (FTIR). The spectroscopic investigations revealed a considerable influence of water on the products of anodic dissolution of cobalt in methanol based solutions. It was also observed that alcohol particles are strongly adsorbed on a surface of the obtained cobalt compounds, what hampers the identification of the final product. The aim of the study is the anodic dissolution of cobalt using methanol as solvent.
Źródło:
Archives of Foundry Engineering; 2015, 15, 4 spec.; 143-146
1897-3310
2299-2944
Pojawia się w:
Archives of Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Oxide Scales Formed on Different Co-Ni Based Superalloys During Isothermal Oxidation at 800 and 900°C
Autorzy:
Migas, D.
Kierat, M.
Moskal, G.
Powiązania:
https://bibliotekanauki.pl/articles/2049616.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
γ–γ′ cobalt-based superalloys
high temperature oxidation
Co-Ni superalloy
W-free cobalt superalloys
Opis:
In this investigation, the formation of oxide scales on different Co-Ni based superalloys of γ–γ′ type was analyzed. Co-20Ni-7Al-7W (at.%) alloy as well as its W-free modifications based on Co-Ni-Al-Mo-Nb and Co-Ni-Al-Ta systems was analyzed under conditions of high temperature oxidation at 800 and 900°C. Therefore, the alloys were isothermally oxidized at selected temperatures for 100 h in laboratory furnace. Afterwards, the oxidation products were evaluated by means of X-ray diffraction (XRD), optical microscopy (OM) and scanning electron microscopy (SEM). The performed tests showed that W-free alloys exhibit worse oxidation resistance compared to those of Co-Ni-Al-W alloys. After oxidation at 900°C, all alloys were prone of oxide spallation. The scales characterized by oxide peeling were mostly composed of complex Co-based oxides, including CoWO4, CoTa2O6, Co2Mo3O8, CoNb2O6.
Źródło:
Archives of Metallurgy and Materials; 2021, 66, 1; 5-14
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of Internal Scrap on Mechanical Properties of Selected Cobalt Alloys
Autorzy:
Dęsoł, B.
Zapała, R.
Pałka, P.
Powiązania:
https://bibliotekanauki.pl/articles/106965.pdf
Data publikacji:
2017
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
cobalt alloy
mechanical properties
fracture
scrap
Opis:
This paper presents the results of mechanical tests carried out on two different commercially available cobalt alloys applied in dental prosthetics for the production of frame dentures. The test samples were obtained by the method of investment casting using as a charge pure primary materials and pure primary materials mixed with various additions of process scrap (25, 50, and 75%). The tests showed that the alloys could not reach the mechanical properties reported by the manufacturer in either case. In the case of the alloy without the addition of tantalum, the general conclusion was that both the plastic and strength properties decreased with increasing amounts of the introduced process scrap. The mechanical properties (mainly elongation) of the alloy containing Ta reached the highest values in the samples containing 75% of the process scrap. Examinations of fractures carried out by SEM have revealed their varied character – ductile or transcrystalline. All of the samples tested showed the presence of dendrites and solidification areas, with shrinkage porosity occurring in the internal sample zones.
Źródło:
Journal of Casting & Materials Engineering; 2017, 1, 3; 59-63
2543-9901
Pojawia się w:
Journal of Casting & Materials Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Manganese oxide based aerogels
Autorzy:
Rudnicka, Małgorzata
Łata, Joanna
Kupracz, Piotr
Powiązania:
https://bibliotekanauki.pl/articles/1161877.pdf
Data publikacji:
2018
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
aerogel
cobalt
manganese
nickel
supercritical drying
Opis:
High purity inorganic aerogels synthetized during sol-gel process show considerable potential for large-scale production. Cobalt-manganese oxides, manganese-nickel oxides and cobalt-manganese-nickel oxides aerogels were obtained during gelation process of transition metal salts. All samples were dried in supercritical conditions. Their specific surface was obtained using both Brunauer-Emmet-Teller and Langmuir methods. Moreover, images received from SEM helped to confirm porous structure.
Źródło:
World Scientific News; 2018, 112; 217-225
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of cobalt chloride on soybean seedlings subjected to cadmium stress
Autorzy:
Chmielewska-Bak, J.
Lefevre, I.
Lutts, S.
Kulik, A.
Deckert, J.
Powiązania:
https://bibliotekanauki.pl/articles/58317.pdf
Data publikacji:
2014
Wydawca:
Polskie Towarzystwo Botaniczne
Tematy:
environment pollution
cobalt chloride
cobalt
heavy metal
soybean
Glycine max
gene expression
signalling
seedling
cadmium stress
Opis:
Contamination of the environment with heavy metals such as Cd is a serious problem of modern world. Exposure of plants to Cd leads to oxidative stress, inhibition of respiration and photosynthesis, increased rate of mutation and, as a consequence, stunted growth and yield decrease. One of the common reactions of plants to cadmium stress is over-production of ethylene, however the exact role of this hormone in plants response to Cd is still unrecognized. The aim of the present study is evaluation of the impact of an ethylene synthesis inhibitor, Co, on the response of soybean seedlings to cadmium stress. The experiments included measurements of growth, cell viability, ethylene production and expression of genes associated with cellular signaling in soybean seedlings exposed to CdCl2 (with Cd in a concentration of 223 μM) and/or CoCl2 (with Co in concentration of 4.6 μM). Surprisingly, the results show that Co has no effect on ethylene biosynthesis, however, it affects cell viability and expression of Cd-induced genes associated with plant signaling pathways. The affected genes encode mitogen-activated protein kinase kinase2 (MAPKK2), nitrate reductase and DOF1 and bZIP2 transcription factors. The role of Co in plants response to cadmium stress and its potential use as an ethylene inhibitor is discussed.
Źródło:
Acta Societatis Botanicorum Poloniae; 2014, 83, 3
0001-6977
2083-9480
Pojawia się w:
Acta Societatis Botanicorum Poloniae
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The influence of cobalt ions on growth and enzymatic activity of entomopathogenic fungi used in biological plant protection
Autorzy:
Łopusiewicz, Ł.
Mazurkiewicz-Zapałowicz, K.
Tkaczuk, C.
Bartkowiak, A.
Powiązania:
https://bibliotekanauki.pl/articles/2084794.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
cobalt
entomopathogenic fungi
enzymatic activity
heavy metals
Opis:
This study focused on the effect of heavy metal cobalt ions (at concentrations of 1–1000 ppm) on the development and enzymatic activity of four entomopathogenic fungi: Beauveria bassiana, Beauveria brongniartii, Isaria fumosorosea and Metarhizium robertsii, commonly used in biological plant protection. It was found that each of the tested species of fungi reacted individually to contact with the Co2+ ions at their various concentrations. Depending on the variants of the experiment carried out, there were changes in the development of the mycelia (mainly growth inhibition) and their morphological features (color and structure) in comparison to the control samples. Co2+ ions had a fungistatic effect on all fungal strains, whereas a fungicidal effect was noted at concentrations of 750 ppm and 1000 ppm against M. robertsii and I. fumosorosea, respectively. In addition, there was a discrepancy in enzymatic activity between the tested fungal species developing in the medium with varying concentrations of metal salt. The inhibitory effect of Co2+ ions on lipase production was observed in I. fumosorosea. Protease production was stimulated in B. bassiana at all Co2+ concentrations, whereas in M. robertsii this effect was noted at 1 ppm. The changing dynamics of extracellular fungal hydrolases, due to the action of Co2+ ions, may translate into the role of these microorganisms in the processes of insect pathogenesis. This work suggests that severe pollution of the environment by cobalt could be a restrictive factor for the development and pathogenicity of entomopathogenic fungi and must be taken into account for their successful application in biological plant protection.
Źródło:
Journal of Plant Protection Research; 2020, 60, 1; 58-67
1427-4345
Pojawia się w:
Journal of Plant Protection Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Structural and magnetic properties of cobalt ferrite nanopowders synthesis using contact non-equilibrium plasma
Autorzy:
Frolova, L.
Derimova, A.
Butyrina, T.
Powiązania:
https://bibliotekanauki.pl/articles/1052775.pdf
Data publikacji:
2018-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
nanomaterials
cobalt
ferrite
Fe/Co molar ratio
Opis:
Different grades of magnetic cobalt ferrite (Co_xFe_{3-x}O₄) nanoparticles were synthesized with various molar ratios of Fe²⁺ to Co²⁺ ions in the initial salt solutions method with using contact non-equilibrium plasma. The crystal structure and morphology of the nanoparticles are obtained from X-ray diffraction and transmission electron microscopy studies. With an increase in the value of x, the saturation magnetization for the samples of CoFe₂O₄ has decreased from 150.9 emu/g to 1.2 emu/g. The dependence of the coercive force on x is extremal with a plateau maximum corresponding to the x=0.5-1.25.
Źródło:
Acta Physica Polonica A; 2018, 133, 4; 1021-1023
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of Dissolved Oxygen on the Corrosion Behaviour in Ringers Solution and Artificial Saliva of Co-Mo Nano-Crystalline Coatings Electrodeposited on Co and 316L Substrates
Autorzy:
Vignal, V.
Krawiec, H.
Latkiewicz, M.
Powiązania:
https://bibliotekanauki.pl/articles/353806.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
cobalt
molybdenum
nanocrystalline coating
corrosion
dissolved oxygen
Opis:
The influence on the corrosion behaviour of Co-Mo nano-crystalline coatings of dissolved oxygen is studied in the Ringer’s solution and artificial saliva at 25°C. This was done by means of potentiodynamic tests and surface observations. It was shown that dissolved oxygen has no influence on passivity, oxidation of the coating and selective dissolution of cobalt. By contrast, dissolved oxygen affects corrosion. General corrosion was observed in the Ringer’s solution whereas pitting corrosion was found in artificial saliva.
Źródło:
Archives of Metallurgy and Materials; 2019, 64, 1; 39-43
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Application of Hollow Fiber Supported Liquid Membrane for Extraction of Cobalt by Cyanex 272
Autorzy:
Swain, Basudev
Lee, Jae-Chun
Kim, Dae-Guen
Lee, Chan Gi
Powiązania:
https://bibliotekanauki.pl/articles/354650.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Cyanex 272
hollow fiber supported
cobalt recovery
Opis:
Considering the advantages of hollow fiber supported liquid membrane (HFSLM), it has been applied for extraction of Co(II) with a motivation to extract cobalt from various waste resources. Extraction efficiency and transport behavior of Co(II) through HFSLM containing Cyanex 272 diluted in kerosene were investigated. Experiments were performed as a function of aqueous feed solution velocity (1000 mL/min) for both feed and strip, pH of feed solution in the range of 4.00-6.75, the carrier concentration of 25-1000 mol/m3, and acid concentration in strip solution of 1-500 mol/m3 on. The mass transfer rate or flux J Co(II), which is a function of metal concentration, volume of solution, and membrane area were analyzed. The optimum condition for extraction of Co(II) was pH of 6.00, Cyanex 272 concentration of 500 mol/m3 and H2 SO4 concentration of 100 mol/m3.
Źródło:
Archives of Metallurgy and Materials; 2019, 64, 3; 845-850
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Separation of Co from Ni and Li from chloride media using polymer inclusion membrane system with thiosalicylate based ionic liquid
Autorzy:
Pospiech, Beata
Powiązania:
https://bibliotekanauki.pl/articles/2175434.pdf
Data publikacji:
2022
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
cobalt
lithium
Ionic liquids
polymer inclusion membranes
Opis:
The selective removal of cobalt(II) from aqueous chloride solutions containing nickel(II) and lithium(I) was studied. The facilitated transport of metal ions through polymer inclusion membranes (PIMs) with trihexyl(tetradecyl)phosphonium thiosalicylate [PR4][TS] under various conditions was analyzed. In order to optimize the separation process, several factors such as the ion carrier concentration in the membrane as well as of the effect of the concentration of the acids in the source/receiving phases were investigated. The results show that PIM containing 25% CTA as the polymer support, 40% NPOE as the plasticizer and 35% [PR4][TS] allow the selective recovery of more than 90% of cobalt(II) from 6 mol/dm3 hydrochloric acid into 0.5 mol/dm3 sulfuric acid.
Źródło:
Physicochemical Problems of Mineral Processing; 2022, 58, 6; art. no. 152997
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Antioxidant Enzyme Mechanism of Cluster Bean (Cyamopsis tetragonaloba (L.) Taub). Under Cobalt Stress
Autorzy:
Jayakumar, Kaliyamoorthy
Powiązania:
https://bibliotekanauki.pl/articles/1076708.pdf
Data publikacji:
2019
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Catalase
Cobalt
Cyamopsis tetragonaloba
Peroxidasa
Polyphenol oxidase
Opis:
The research work has been carried out to estimate the low level cobalt application enhance antioxidant enzyme activities of cluster bean plants. The experiments were conducted in earthen pots containing 3 kg of air dried soil. The inner surface of pots was lined with polythene sheet. Cluster bean plants were raised in soil amended with different concentration of cobalt (0, 50, 100, 150, 200 and 250 mg/kg). The antioxidant enzyme activities were analysed at 30, 60, and 90 days after sowing (DAS). There found a significant enhance antioxidant enzyme activities at 50 mg/kg cobalt application in the soil in all the sampling days when compared to control. Further increase in the cobalt level (100-250 mg/kg) in the soil decreased antioxidant enzyme activities of cluster bean plants in all the sampling days.
Źródło:
World News of Natural Sciences; 2019, 24; 64-70
2543-5426
Pojawia się w:
World News of Natural Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Properties and activity of the cobalt catalysts for NH3 &enspsynthesis obtained by co-precipitation – the effect of lanthanum addition
Autorzy:
Zybert, M.
Karasińska, M.
Truszkiewicz, E.
Mierzwa, B.
Raróg-Pilecka, W.
Powiązania:
https://bibliotekanauki.pl/articles/778653.pdf
Data publikacji:
2015
Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:
ammonia synthesis
cobalt catalyst
promoter
lanthanum
coprecipitation
Opis:
In modern research on catalysts for NH3&enspsynthesis a lot of attention is paid to cobalt. In this work the new catalytic systems based on cobalt are presented. Unsupported cobalt catalysts singly promoted (La or Ba) and doubly promoted (La and Ba) were prepared and tested in NH3&enspsynthesis reaction under commercial synthesis conditions. Characterization studies revealed that lanthanum plays a role of a structural promoter, which improves the surface of catalyst precursors and prevents from sintering during calcination. However, lanthanum has a negative effect on the reduction of cobalt oxide, but the addition of barium promoter (Co/La/Ba catalyst) diminishes the negative impact of La. The co-promotion of cobalt with lanthanum and barium results in the increasing of the active phase surface and improvement of its activity in NH3&enspsynthesis.
Źródło:
Polish Journal of Chemical Technology; 2015, 17, 1; 138-143
1509-8117
1899-4741
Pojawia się w:
Polish Journal of Chemical Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Microstructure and Corrosion Behaviour of Co-Mo/TiO2 Nano-Composite Coatings Formed on Disk and Wire Electrodes by Electrodeposition
Autorzy:
Krawiec, H.
Vignal, V.
Latkiewicz, M.
Powiązania:
https://bibliotekanauki.pl/articles/352460.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
cobalt
molybdenum
nanocrystalline coating
corrosion
dissolved oxygen
Opis:
The influence of the electrode geometry on the microstructure and corrosion behaviour of Co-Mo nano-crystalline coatings elaborated by electrodeposition is studied. The corrosion behaviour was determined in the Ringer’s solution at 25°C. Electrodeposition mechanisms are also discussed as a function of the electrode geometry. The electrode geometry was found to affect the growth rate and, under certain conditions, the microstructure (existence of channels and pores). It does not have influence on the corrosion behaviour.
Źródło:
Archives of Metallurgy and Materials; 2019, 64, 1; 23-28
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electrochemical characteristics of a cobalt alloy with a protective passive layer
Autorzy:
Reimann, Ł.
Powiązania:
https://bibliotekanauki.pl/articles/355202.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
electrochemical characteristics
cobalt alloy
protective passive layer
Opis:
The aim of this study was to assess the quality of the passive layer formed on the surface of a CoCr alloy used on dentures to see the effect on resistance to pitting corrosion and electrochemical parameters. Studies were performed using on potentiodynamic tests and electrochemical impedance spectroscopy. The passive layer was formed spontaneously and by electrochemical method on samples after casting and after simulation porcelain firing on metal. Samples of the passivation electrochemical characterized by the improvement in corrosion resistance. Prolonging the passivation time from one to 24 hours and increasing the potential value from 0 to 200 mV improved the quality of the passive layer and all characteristics of electrochemical parameters.
Źródło:
Archives of Metallurgy and Materials; 2016, 61, 3; 1283-1290
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Commercial sponges in heterogeneous catalysis: developing novel composites with cobalt and silver
Autorzy:
Żółtowska, Sonia
Modelska, Martyna
Piasecki, Adam
Jesionowski, Teofil
Powiązania:
https://bibliotekanauki.pl/articles/1450217.pdf
Data publikacji:
2020
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
commercial sponge
biomimetic
4-nitrophenol
cobalt
silver
Opis:
The use of commercial sponges in materials science has gained much recent attention. Their unique properties, namely a fibrous, rigid skeleton, thermal stability and resistance to acid and basic hydrolysis, have been the primary motivation to use them in the development of new composites. In this work, a simple method of immobilization of cobalt and silver cations, followed by their reduction using sodium borohydride, was successfully applied for the first time to obtain functionalized spongin scaffolds. Three different materials, labeled Co_spongin, Ag_spongin and Co-Ag_spongin, were prepared. Their morphological and physicochemical properties were explored using various techniques (SEM+EDS, TG/DTA, FTIR). The focal point of the research was the application of the resulting materials in the reaction of 4-nitrophenol reduction with sodium borohydride in water. It was found that all of the composites possess superior activity in the reduction of 4-nitrophenol, achieving high rate constants of 0.31 min-1 for Ag_spongin, 0.52 min-1 for Co_spongin and 0.86 min-1 for Co-Ag_spongin. Reusability tests showed that all of the composites could be reused five times. Additional structural analysis after catalytic application showed no visible changes in the morphology of the catalysts. The results indicate that spongin can be considered as a facile, cost-effective, renewable and environmentally friendly three-dimensional support for use in heterogeneous catalysis.
Źródło:
Physicochemical Problems of Mineral Processing; 2020, 56, 6; 89-100
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ba0.5Sr0.5Co0.8Fe0.2O3-σ and La0.6Sr0.4Co0.8Fe0.2O3-σ composite cathode for solid oxide fuel cell
Autorzy:
Mosiałek, M.
Kędra, A.
Krzan, M.
Bielańska, E.
Tatko, M.
Powiązania:
https://bibliotekanauki.pl/articles/355878.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
barium strontium cobalt ferrite
lanthanum strontium cobalt ferrite
solid oxide fuel cell
oxygen reduction reaction
electrochemical impedance spectroscopy
Opis:
Composite cathodes contain Ba0.5Sr0.5Co0.8Fe0.2O3-σ and La0.6Sr0.4Co0.8Fe0.2O3-σ were tested in different configuration for achieving cathode of area specific resistance lower than Ba0.5Sr0.5Co0.8Fe0.2O3-σ and La0.6Sr0.4Co0.8Fe0.2O3-σ cathodes. Electrodes were screen printed on samaria-doped ceria electrolyte half-discs and tested in the three electrode setup by the electrochemical impedance spectroscopy. Microstructure was observed by scanning electron microscopy. The lowest area specific resistance 0.46 and 2.77 Ω cm-2 at 700 °C and 600 °C respectively revealed composite cathode contain Ba0.5Sr0.5Co0.8Fe0.2O3-σ and La0.6Sr0.4Co0.8Fe0.2O3-σ in 1:1 weight ratio. The area specific resistance of this cathode is characterized by the lowest activation energy among tested cathodes.
Źródło:
Archives of Metallurgy and Materials; 2016, 61, 3; 1483-1488
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of neutralising substances on reducing the influence of cobalt on the content of selected elements in soil
Autorzy:
Kosiorek, M.
Wyszkowski, M.
Powiązania:
https://bibliotekanauki.pl/articles/2082494.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Instytut Agrofizyki PAN
Tematy:
cobalt contamination
sorbents
soil
elements
C:N ratio
Opis:
The objective of this study was to determine the effect of cobalt on the content of total organic carbon, total nitrogen, the available forms of phosphorus, potassium and magnesium and the C:N ratio in soil, following the application of neutralising substances. The effect of cobalt in soil was tested on oats (Avena sativa L.). In order to limit the effect of cobalt, the soil was enriched with neutralising substances, i.e. manure, clay, charcoal, zeolite and calcium oxide. In the series with no neutralising substance, the increasing doses of cobalt only caused an increase in the amount of the available potassium, and the highest Co dose favoured an increase in the organic carbon content and a wider C:N ratio in soil. All the substances affected the content of the available potassium in soil, with charcoal, and especially manure, contributing to its elevated accumulation. Besides, manure fostered a growth in the soil content of the available phosphorus, charcoal - the content of organic carbon and the available potassium, and zeolite - the total nitrogen content, while calcium oxide promoted a higher content of total nitrogen and the available phosphorus. Clay and charcoal (unlike zeolite) caused the widening of the C:N ratio in soil.
Źródło:
International Agrophysics; 2019, 33, 2; 153-159
0236-8722
Pojawia się w:
International Agrophysics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Tribological properties of Stellite 6 cobalt alloy implanted with nitrogen ions determined in the tests conducted in engine fuel atmosphere
Autorzy:
Kamiński, M.
Budzyński, P.
Powiązania:
https://bibliotekanauki.pl/articles/102789.pdf
Data publikacji:
2017
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
Stellite 6
tribology
cobalt alloy
engine
automotive industry
Opis:
The influence of nitrogen ion implantation on the tribological properties of Stellite 6 cobalt alloy was investigated. The tribological tests were conducted using a pin / ball on disc in the atmosphere of engine fuels. In the study, cobalt alloy was implanted with 60 keV nitrogen ions at the fluence of 1∙1016 and 5∙1016 N+/cm2. The wear trace was measured using the Form Talysurf Intra Taylor Hobson profilometer. The results demonstrate that nitrogen ion implantation affects the friction coefficient and wear. The effect of nitrogen ion implantation depends on the environment in which the tribological test is carried out, the sample temperature and the presence of friction products in the friction node.
Źródło:
Advances in Science and Technology. Research Journal; 2017, 11, 4; 215-219
2299-8624
Pojawia się w:
Advances in Science and Technology. Research Journal
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Behaviour of the exhaust valve cladding face under the service conditions
Autorzy:
Kończewicz, W.
Smoleńska, H.
Powiązania:
https://bibliotekanauki.pl/articles/244130.pdf
Data publikacji:
2009
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
exhaust valve
laser cladding
cobalt alloy
service wear
Opis:
During the ship engine operation one of the key problems is the exhaust valve durability. A special interest is in valve head face because this narrow part of the valve is responsible for tightness. Cobalt base laser cladding layer on the exhaust valve head face have been investigate under real service condition using the laboratory two-stroke diesel engine L22 for two years. During this time the engine was fuelling with both ordinary light fuel and biodiesel fuel. After removing from the valve head from the cylinder head the face surface were fully inspected optically. There were no damages and the surface was shining in the great deal however some dark "spots " on it. The samples made of the used valve head underwent microstructural investigation and hardness measurements. There were no observed substantial microstructural changes neither in the surface of the layer nor in the bulk of the clad. The decrease of the hardness numbers was observed but still clad layer presented higher hardness than steel base. This type ofclad layer underwent intensive laboratory examinations which contained oxidation experiments at different temperatures and corrosion in exhaust gases and with the present service experiment this method of valve head hard facing is suitable for practical applications.
Źródło:
Journal of KONES; 2009, 16, 1; 265-271
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Diffusion of boron in cobalt sinters
Dyfuzja boru w spiekach kobaltu
Autorzy:
Borowiecka-Jamrozek, J.
Lachowski, J.
Powiązania:
https://bibliotekanauki.pl/articles/354296.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
diffusion
sinter
cobalt
boronizing
dyfuzja
spiek
kobalt
bor
Opis:
The paper describes the process of diffusion taking place at the surface of sinters produced from Co Extrafine powder after saturation with boron. Boronizing was performed at a temperature of 950°C for 6 and 12 hours by applying B4C powder as a depositing source, NH4Cl + NaF as an activator and Al2O3 as an inert filler. The study involved determining the diffusion coefficient, which required analyzing the microstructure and thickness of the layers and the process time. The images obtained with a Leica DM-4000 optical microscope revealed a two-phase structure of the boride layers. The presence of the two phases, i.e. CoB and Co2B, was confirmed by X-ray diffraction (XRD). A model of diffusion of boron atoms into the cobalt substrate was developed assuming the reaction diffusion mechanism. This model was used to calculate the diffusion coefficient. It required taking account of the interatomic potentials of boron and cobalt. The calculation results were compared with the experimental data concerning the diffusion of boron in other materials.
W pracy przedstawiono wyniki badań procesu dyfuzji w warstwach powierzchniowych uzyskanych w wyniku nasycenia borem spieków otrzymanych z proszku kobaltu gatunku Co Extrafine. Warstwy otrzymano przy zastosowaniu proszkowej metody borowania opartej na wykorzystaniu mieszaniny o składzie: B4C jako składnik podstawowy stanowiący źródło boru, (NH4Cl + NaF) aktywator i Al2O3 jako wypełniacz. Zachowane były następujące parametry procesu: temperatura 950°C, czas 6h i 12h. Badania obejmowały wyznaczenie współczynnika dyfuzji w oparciu o strukturę, grubość uzyskanych i czas nasycenia warstw. Obserwacji naniesionych warstw dokonano za pomocą mikroskopu optycznego Leica DM-4000. Zdjęcia ujawniły dwufazową strukturę warstw borkowych. Badania rentgenowskie potwierdziły występowanie faz o składzie: CoB i Co2B. Zbudowano model dyfuzji atomów boru w strukturze kobaltu zakładając dyfuzję reaktywną. Obliczono współczynnik dyfuzji w oparciu o model atomowy dyfuzji wykorzystując potencjały oddziaływan pomiędzy atomami boru i kobaltu. Otrzymane wyniki porównano z danymi doświadczalnymi dyfuzji boru w innych materiałach.
Źródło:
Archives of Metallurgy and Materials; 2013, 58, 4; 1131-1136
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Cobalt adsorption on the nano-hydroxyapatite matrix: isotherm and kinetic studies
Autorzy:
Narwade, V. N.
Khairnar, R. S.
Powiązania:
https://bibliotekanauki.pl/articles/202076.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
hydroxyapatite
cobalt
adsorption
XRD
SEM
hydroksyapatyt
kobalt
adsorpcja
Opis:
Cobalt radionuclide is one of the prime contaminants generated during operation of pressurized heavy water. The paper reports the study of cobalt adsorption on hydroxyapatite (HAp) nanoceramic. A modified wet chemical precipitation method is used for HAp synthesis. The HAp nano-material is characterized by XRD, FTIR, TG/DTA, AFM, SEM, and EDAX. Experiments are performed in batches to observe the effect of cobalt adsorption on HAp matrix. The adsorption of cobalt on HAp is examined at room temperature. The isotherm and kinetic studies showed that the Freundlich isotherm and pseudo-second order model are the best choices to describe the nature of adsorption.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2017, 65, 2; 131-137
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electrochemical deposition of cobalt-nickel coatings in a constant magnetic field
Autorzy:
Miękoś, Ewa
Klepka, Tomasz
Zieliński, Marek
Sroczyński, Dariusz
Powiązania:
https://bibliotekanauki.pl/articles/2146891.pdf
Data publikacji:
2022
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
cobalt-nickel coatings
constant magnetic field
electrochemical deposition
Opis:
The electrochemical deposition of Co-Ni coatings on gold-disc electrode with and without of constant magnetic field (CMF) has been investigated using cyclic voltammetry (CV), scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDX). The EDX results showed that CMF applied during the electrodeposition of Co-Ni coatings affects their composition. In particular, an increase by 17% in the content of cobalt in coating, i.e. the main component, with a simultaneous decrease of nickel content has been observed when magnetic induction B of 1200 mT was applied compare to this without of CMF. Moreover, it has been supposed that the increase of internal stresses in electrodeposited Co-Ni coatings under CMF can be attributed to a decrease in their thickness.
Źródło:
Physicochemical Problems of Mineral Processing; 2022, 58, 2 (Special issue - selected papers conference: Physicochemistry of interfaces - instrumental methods); art. no. 146066
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of alkali metal promoters on catalytic performance of Co-based catalysts in selective hydrogenation of aniline to cyclohexylamine
Autorzy:
Valeš, Roman
Zapletal, Martin
Krupka, Jiří
Powiązania:
https://bibliotekanauki.pl/articles/2204145.pdf
Data publikacji:
2023
Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:
Aniline
Cyclohexylamine
Hydrogenation
Cobalt catalyst
Alkali metal carbonate
Opis:
In this study, a series of Co-based catalysts with alkali metal carbonate promoters were prepared to investigate the interrelation between promotion effect of these carbonates and catalytic performance for aniline hydrogenation to cyclohexylamine in vapour phase. The chemical promoters Li2CO3 and Na2CO3 leading to decrease in catalytic activity of cobalt catalysts for aniline hydrogenation. Catalysts with K2CO3 and Cs2CO3 loadings have practically no catalytic activity for hydrogenation of aniline. Results of TPD of aniline proved that presence of alkali metals carbonates restricts the adsorption of aniline on the surface of cobalt catalysts. Further, it was found that the addition of Na2CO3 greatly enhances the catalytic selectivity towards the cyclohexylamine and inhibits the consecutive reactions of cyclohexylamine leading to formation of by-products such as dicyclohexylamine and N-phenylcyclohexylamine.
Źródło:
Polish Journal of Chemical Technology; 2023, 25, 1; 1--7
1509-8117
1899-4741
Pojawia się w:
Polish Journal of Chemical Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Badania tribologiczne stopów kobaltu stosowanych jako biomateriały
Tribological research of cobalt alloys used as biomaterials
Autorzy:
Karpiński, R.
Walczak, M.
Śliwa, J.
Powiązania:
https://bibliotekanauki.pl/articles/101804.pdf
Data publikacji:
2015
Wydawca:
Politechnika Lubelska. Polskie Towarzystwo Promocji Wiedzy
Tematy:
stopy kobaltu
biomateriały
tribologia
cobalt alloys
biomaterials
tribology
Opis:
Poniższe opracowanie zawiera informacje dotyczące stopów kobaltu stosowanych w stomatologii oraz medycynie. Praca zawiera przegląd literatury opisujący ogólne właściwości stopów kobaltu. Opisano także wpływ warunków wytwarzania i wykorzystywanych dodatków stopowych na strukturę oraz właściwości mechaniczne tych stopów. W opracowaniu umieszczona została metodyka przeprowadzonych badań oraz uzyskane wyniki. Do badań wybrane zostały dwa stopy na osnowie kobaltu Co-CrMo-W oraz Co-Cr-Ni-Mo. Pierwszy z nich wytworzony został techniką odlewniczą drugi natomiast wyniku obróbki plastycznej. Przeprowadzona została analiza składu chemicznego, a następnie badania tribologiczne in vitro zrealizowane na tribotesterze typu „ball-on-disc”. Przedstawiona została porównawcza charakterystyka tribologiczna tych stopów.
This study provides information about the cobalt alloys used in dentistry and medicine. The work includes a review of the literature describing the general properties of cobalt alloys. In addition it describes the impact of the manufacturing conditions and alloy additives used , on the structure and mechanical properties of these alloys. The research methodology and the results obtained has been presented in the study. Two cobalt-based alloys Co-CrMo-W and Co-Cr-Ni-Mo were selected for the tests. The first one was prepared with the use of casting technique whereas the second was obtained due to plastic forming. An analysis of the chemical composition and in vitro tribological tests with the use of tribotester of "ball-on-disc" type was conducted. Comparative tribological characteristics of these alloys has been presented.
Źródło:
Journal of Technology and Exploitation in Mechanical Engineering; 2015, 1, 1-2; 17-32
2451-148X
Pojawia się w:
Journal of Technology and Exploitation in Mechanical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Adsorption of copper, cobalt, and manganese ions from aqueous solutions using oxidized multi-walled carbon nanotubes
Autorzy:
Namin, P. E.
Powiązania:
https://bibliotekanauki.pl/articles/207476.pdf
Data publikacji:
2016
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
copper
cobalt
water solution
miedź
kobalt
roztwór wodny
Opis:
Adsorption of Cu2+, Co2+, and Mn2+ metal ions on oxidized multi-walled carbon nanotubes (O-MWCNTs) was investigated as a function of contact time, pH, sorbent dosage, and initial metal ion concentration. Multi-walled carbon nanotubes (MWCNTs) were oxidized using HNO3. All the adsorption experiments were conducted by the batch method. Determination of metal ions was performed by the flame atomic absorption spectrometry. The results showed that the amount of metal ions adsorbed strongly depended on pH. The affinity order of the three adsorbed metal ions by O-MWCNTs was Cu22+> Co2+ > Mn2+.
Źródło:
Environment Protection Engineering; 2016, 42, 4; 75-85
0324-8828
Pojawia się w:
Environment Protection Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study on structures and properties of the laser cladding exhaust valve after service
Autorzy:
Kończewicz, W.
Krużycki, P.
Smoleńska, H.
Powiązania:
https://bibliotekanauki.pl/articles/244029.pdf
Data publikacji:
2010
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
exhaust valve
laser cladding
cobalt alloy
service wear
Opis:
The cobalt base laser cladding layers which were built up on the exhaust valve head face of the heavy loaded marine diesel engine have been investigated. The valve head with cladded face were served successfully for 3000 hours in the engine of the Dar Młodzieży. After removing from the valve head from the cylinder head the face surface were fully inspected. The surface topography and roughness were evaluated. Microstructure on the cross section of the clad layer were analyzed using Scanning Electron Microscope (SEM) equipped with energy dispersive spectroscopy (EDS. Also microhardness of the clad layer was measured. The service conditions resulted with the formation of the scale which had different thickness and tended to cracking and spalling. The microstructure of the clad layers after service did not demonstrated serious degradation process. The decrease of the hardness numbers was observed but still clad layer presented higher hardness than steel base. This type of clad layer underwent intensive laboratory examinations which contained oxidation experiments at different temperatures and corrosion in exhaust gases, long time exposition in laboratory engine and in the end 3000 hours successfully service on the ship. After such experience laser cladding cobalt base layers may be recommended as a useful solutionfor both prolongs of the service life and a method of the regeneration of the slightly used valve heads is suitable for practical applications.
Źródło:
Journal of KONES; 2010, 17, 3; 211-216
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Recovery of valuable metals from zinc plant residue through separation between manganese and cobalt with n-n reagent
Autorzy:
Moradkhani, D.
Sedaghat, B.
Khodakarami, M.
Ataei, I.
Powiązania:
https://bibliotekanauki.pl/articles/110865.pdf
Data publikacji:
2014
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
zinc plant residue
manganese
cobalt
beta naphthol
kinetics
Opis:
Recovery and separation of cobalt and manganese from one of zinc plant residues (ZPR), namely hot filter cake (HFC) using a hydrometallurgical process was studied. The process is carried out in four steps as follows: (1) washing zinc, (2) reductive leaching with hydrogen peroxide, (3) cadmium cementation with zinc powder and (4) separation of cobalt from manganese with beta naphthol. In this research, the separation between manganese and cobalt from the HFC using N-N reagent was investigated. The influence of several parameters on the course of the reaction such as N-N quantity, pH, temperature and reaction time was also examined. The optimum separation conditions were found to be N-N quantity: 8 times of stoichiometric value, time: 30 min, temperature: 25 °C and pH = 1.5. Using the optimized conditions, the cobalt and manganese precipitation was nearly 99% and 0%, respectively. A kinetic study of manganese precipitation through N-N reagent has been carried out to assess the effect of kinetics parameters. The data obtained for the leaching kinetics indicated that the precipitation of manganese is an ash diffusion controlled reaction and the reaction activation energy is equal to 1.4kJ/mol.
Źródło:
Physicochemical Problems of Mineral Processing; 2014, 50, 2; 735-746
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Cobalt-lanthanum catalyst precursors for ammonia synthesis: determination of calcination temperature and storage conditions
Autorzy:
Zybert, M.
Tarka, A.
Mierzwa, B.
Raróg-Pilecka, W.
Powiązania:
https://bibliotekanauki.pl/articles/778044.pdf
Data publikacji:
2017
Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:
ammonia synthesis
catalyst precursor
cobalt
lanthanum
thermal analysis
Opis:
A thermal decomposition of a cobalt-lanthanum catalyst precursor containing a mixture of cobalt and lanthanum compounds obtained by co-precipitation were studied using thermal analysis coupled with mass spectrometry (TG-MS). Studies revealed that the calcination in air at 500°C is sufficient to transform the obtained cobalt precipitate into Co3 O4 , but it leads to only partial decomposition of lanthanum precipitate. In order to obtain Co/La catalyst precursor containing La2 O3  the calcination in air at the temperature about 800°C is required. However, it is unfavorable from the point of view of textural properties of the catalyst precursor. A strong effect of storage conditions on the phase composition of the studied cobalt-lanthanum catalyst precursor, caused by the formation of lanthanum hydroxide and lanthanum carbonates from La2 O3  when contacting with air, was observed.
Źródło:
Polish Journal of Chemical Technology; 2017, 19, 2; 61-66
1509-8117
1899-4741
Pojawia się w:
Polish Journal of Chemical Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ultrasound-assisted emulsification–microextraction and spectrophotometric determination of cobalt, nickel and copper after optimization based on Box-Behnken design and chemometrics methods
Autorzy:
Doroudi, Z.
Niazi, A.
Powiązania:
https://bibliotekanauki.pl/articles/778452.pdf
Data publikacji:
2018
Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:
ultrasound-assisted emulsification–microextraction
chemometrics
cobalt
nickel
copper
Opis:
A fast, simple, and economical method for extraction, preconcentration and determination of cobalt, nickel and copper as their 1-(2-pyridilazo) 2-naphthol (PAN) complexes based on ultrasound-assisted emulsification–microextraction (USAEME) and multivariate calibration of spectrophotometric data is presented. Various parameters affecting the extraction efficiency were optimized both with univariate and Box–Behnken design. The resolution of ternary mixtures of these metallic ions was accomplished by using partial least-squares regression (PLS), orthogonal signal correction-partial least-squares regression (OSC-PLS), and orthogonal signal correction-genetic algorithmspartial least-squares regression (OSC-GA-PLS). Under the optimum conditions, the calibration graphs were linear in the range of 2.0–150.0, 2.0–120.0 and 2.0–150.0 ng mL−1  for Co2+ , Ni2+ , and Cu2+ , respectively, with a limit of detection of 0.14 (Co2+ ), 0.13 (Ni2+ ) and 0.14 ng mL−1  (Cu2+ ) and the relative standard deviation was <2.5%. The method was successfully applied to the simultaneous determination of these cations in different samples.
Źródło:
Polish Journal of Chemical Technology; 2018, 20, 1; 21-28
1509-8117
1899-4741
Pojawia się w:
Polish Journal of Chemical Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Studies on the recrystalization of nanocrystalline metals
Autorzy:
Lendzion-Bieluń, Z.
Gleń, M.
Powiązania:
https://bibliotekanauki.pl/articles/778633.pdf
Data publikacji:
2007
Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:
kobalt nanokrystaliczny
rekrystalizacja
nanokrystaliczne metale
nanocrystalline cobalt
recrystalization
Opis:
The influence of the promoters such as CaO, Al2O3 and K2O on the specific surface area of the nanocrystalline cobalt was determined. The recrystalization process of the nanocrystalline cobalt was determined and compared with the examinations conducted on the iron catalyst for ammonia synthesis. The triply promoted nanocrystalline obtained cobalt after the annealing process, has got greater specific surface area than the triply promoted iron.
Źródło:
Polish Journal of Chemical Technology; 2007, 9, 4; 5-7
1509-8117
1899-4741
Pojawia się w:
Polish Journal of Chemical Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Catalytic activity of cobalt and cerium catalysts supported on calcium hydroxyapatite in ethanol steam reforming
Autorzy:
Dobosz, J.
Hull, S.
Zawadzki, M.
Powiązania:
https://bibliotekanauki.pl/articles/779330.pdf
Data publikacji:
2016
Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:
hydroxyapatite
cobalt
cerium
ethanol steam reforming
hydrogen production
Opis:
In this paper, Co,Ce/Ca10(PO4)6(OH)2 catalysts with various cobalt loadings for steam reforming of ethanol (SRE) were prepared by microwave-assisted hydrothermal and sol-gel methods, and characterized by XRD, TEM, TPR-H2, N2 adsorption-desorption measurements and cyclohexanol (CHOL) decomposition tests. High ethanol conversion (close to 100%) was obtained for the catalysts prepared by both methods but these ones prepared under hydrothermal conditions (HAp-H) ensured higher hydrogen yield (3.49 mol H2/mol C2H5OH) as well as higher amount of hydrogen formed (up to 70%) under reaction conditions. The superior performance of 5Co,10Ce/HAp-H catalyst is thought to be due to a combination of factors, including increased reducibility and oxygen mobility, higher density of basic sites on its surface, and improved textural properties. The results also show a significant effect of cobalt loading on catalysts efficiency in hydrogen production: the higher H2 yield exhibit catalysts with lower cobalt content, regardless of the used synthesis method.
Źródło:
Polish Journal of Chemical Technology; 2016, 18, 3; 59-67
1509-8117
1899-4741
Pojawia się w:
Polish Journal of Chemical Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thermal Plasma Decomposition Of Nickel And Cobalt Compounds
Rozkład termiczny w plazmie związków niklu i kobaltu
Autorzy:
Woch, M.
Lis, M.
Kołacz, D.
Kamińska, M.
Staszewski, M.
Powiązania:
https://bibliotekanauki.pl/articles/350973.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
plasma
decomposition
cobalt
nickel
plazma
rozkład
kobalt
nikiel
Opis:
The paper presents the study on manufacturing of nickel and cobalt powders by thermal plasma decomposition of the carbonates of these metals. It was shown the dependence of process parameters and grain size of initial powder on the composition of final product which was ether metal powder, collected in the container as well as the nanopowder with crystallite size of 70 - 90 nm, collected on the inner wall of the reaction chamber. The occurrence of metal oxides in the final products was confirmed and discussed.
Źródło:
Archives of Metallurgy and Materials; 2015, 60, 2B; 1361-1364
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Microstructure and Functional Properties of Prosthetic Cobalt Alloys CoCrW
Mikrostruktura i właściwości użytkowe protetycznych stopów kobaltu CoCrW
Autorzy:
Nadolski, M.
Golański, G.
Klimas, J.
Szota, M.
Szymański, J.
Powiązania:
https://bibliotekanauki.pl/articles/355916.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
cobalt alloy
microstructure
properties
stopy kobaltu
mikrostruktury
właściwości
Opis:
The material subject to investigation was two commercial alloys of cobalt CoCrW (No. 27 and 28) used in prosthodontics. The scope of research included performing an analysis of microstructure and functional properties (microhardness, wear resistance and corrosion resistance), as well as dilatometric tests. The examined alloys were characterized by diverse properties, which was considerably influenced by the morphology of precipitates in these materials. Alloy No. 27 has a higher corrosion resistance, whereas alloy No. 28 shows higher microhardness, better wear resistance and higher coefficient of linear expansion. Lower value of the expansion coefficient indicates less probability of initiation of a crack in the facing ceramic material.
Badaniu poddano dwa komercyjne stopy kobaltu CoCrW (nr 27 i 28) stosowane w protetyce stomatologicznej. Zakres badań obejmował przeprowadzenie analizy mikrostrukturalnej, właściwości użytkowych (mikrotwardość, odporność na ścieranie i odporność korozyjna) oraz badania dylatometryczne. Badane stopy charakteryzowały się zróżnicowanymi właściwościami na co zasadniczy wpływ miała morfologia wydzieleń w tych materiałach. Stop nr 27 posiada wyższą odporność korozyjną natomiast stop nr 28 wykazuje: wyższą mikrotwardość, lepszą odporność na ścieranie oraz niższy współczynnik rozszerzalności liniowej. Niższa wartość współczynnika rozszerzalności liniowej wskazuje na mniejsze prawdopodobieństwo inicjacji pęknięcia licującego materiału ceramicznego.
Źródło:
Archives of Metallurgy and Materials; 2015, 60, 3A; 1999-2003
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Activity and stability of cobalt-manganese catalysts in the process of methane flameless combustion
Autorzy:
Rotko, Marek
Redko, Vladyslav
Zawadzki, Witold
Powiązania:
https://bibliotekanauki.pl/articles/2079905.pdf
Data publikacji:
2019
Wydawca:
Uniwersytet Marii Curie-Skłodowskiej. Wydawnictwo Uniwersytetu Marii Curie-Skłodowskiej
Tematy:
Methane flameless combustion
Cobalt-manganese catalyst
Complete methane oxidation
Opis:
Oxide cobalt-manganese catalysts with different contents of cobalt and manganese, as well as pure cobalt and manganese catalysts have been tested in the process of methane flameless combustion (complete catalytic oxidation). The X-ray diffraction and X-ray photoelectron spectroscopy results showed that cobalt-manganese catalysts mainly composed of the spinel phase of Co$\text{}_{3}$O$\text{}_{4}$, Mn$\text{}_{2}$CoO$\text{}_{4}$ and/orMnCo$\text{}_{2}$O$\text{}_{4}$. The highest initial activity was presented bythe cobalt-manganese catalyst withahigh cobalt content.However, after 50-hours stability test the highest activity was presented by the cobalt-manganese catalyst with Co and Mn content close to the equimolar value.
Źródło:
Annales Universitatis Mariae Curie-Skłodowska, sectio AA – Chemia; 2019, 74, 2; 89-100
2083-358X
Pojawia się w:
Annales Universitatis Mariae Curie-Skłodowska, sectio AA – Chemia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Wpływ nanotlenku glinu i nanotlenku glinu modyfikowanego kobaltem na mikroorganizmy
Impact of alumina and cobalt-modified alumina on microorganisms
Autorzy:
Mosdorf, P.
Karwowska, E.
Kunicki, R. A.
Karolczak, G.
Powiązania:
https://bibliotekanauki.pl/articles/1819468.pdf
Data publikacji:
2011
Wydawca:
Politechnika Koszalińska. Wydawnictwo Uczelniane
Tematy:
nanotlenek glinu
kobalt
mikroorganizmy
nanokompozyty
alumina nanoparticles
cobalt
microorganisms
Opis:
Przyczyną zainteresowania nanokompozytami są ich unikatowe właściwości fizyczne i chemiczne oraz rosnąca liczba potencjalnych zastosowań. Wykorzystywane są one w elektronice, ceramice, optyce, technikach laserowych, budownictwie, rolnictwie, medycynie, kosmetyce oraz kosmonautyce. Prowadzone są badania nad zastosowaniem nanomateriałów w nowoczesnych systemach podawania leków, fototerapii czy leczeniu chorób neurodegradacyjnych takich jak choroba Wilsona, Alzhaimera i Parkinsona [2]. Nanocząstki o właściwościach magnetycznych wykorzystywane są w diagnostyce, biologii molekularnej - do etykietowania biomolekuł oraz przy bezpośrednim podawaniu leków do komórek nowotworowych [3], jak również jako środki kontrastowe w rezonansie magnetycznym [1]. Stanowią składniki farb, baterii, środków konserwujących i pielęgnacyjnych, kosmetyków, katalizatorów, materiałów dentystycznych, sorbentów i materiałów ściernych.
The growing interest in nanostructural materials and their common application in various areas of life and industry, results in their increasing emission into the natural environment. Most of the present research on the influence of nanoparticles on living cells is carried out using animal or cultured human cells. However there are few data concerning the impact of nanoproducts on microorganisms isolated from the natural environment. The aim of this work was to determine the influence of alumina nanopowder as well as cobalt-modified alumina nanopowder on bacteria isolated from soil, water and air samples. The growth tests allowed to observe that Co-modified alumina nanopowder revealed the stronger antibacterial activity com-paring with alumina without modification. The strains of soil bacteria were the most sensitive to both tested nanopowders, especially to CoO/Al2O3. The growth of 93% of bacteria isolated from soil samples was inhibited by cobalt-modified alumina nanopowder, but only about 20% - by alumina without modification (mainly gram negative rods from genus Pseudomonas). Bacteria isolated from the air, especially from genus Staphylococcus were the less sensitive to alumina nanoparticles. However some of them were sensitive to cobaltmodified alumina nanopowder. It was noticed that in low concentration of nanoproduct, some adaptation processes, allowing bacteria to grow in a presence of nanopowder may be observed, even in case of cobalt-modified alumina characterized by more significant antibacterial properties. Moreover, the sensitivity to tested preparations was attributed to the particular bacterial strains, that was proved by different results obtained for the various strains of the same bacterial species.
Źródło:
Rocznik Ochrona Środowiska; 2011, Tom 13; 1635-1651
1506-218X
Pojawia się w:
Rocznik Ochrona Środowiska
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Recovery of cobalt and nickel by atmospheric leaching of flotation sulfide concentrate from lubin concentrator
Autorzy:
Gibas, K.
Borowski, K.
Chmielewski, T.
Wejman, K.
Powiązania:
https://bibliotekanauki.pl/articles/951849.pdf
Data publikacji:
2015
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
atmospheric leaching
cobalt
nickel
sulphuric acid
Lubin copper concentrate
Opis:
An experimental study on leaching of cobalt and nickel from a Lubin (Poland) sulfide flotation copper concentrate with oxygenated sulphuric acid solution in the presence of iron(III) sulfate is presented. The effect of temperature, iron(III) concentration, initial sulphuric acid concentration, oxygen flow rate and chloride ions addition on cobalt and nickel leaching were examined. The obtained results show, that enhancing investigated leaching parameters increases both the rate and leaching recovery of nickel and cobalt. The effect of iron(III) ions concentration is particularly significant. Additionally, a significant correlation between copper and nickel/cobalt leaching recovery was observed. Due to the fine dissemination of nickel and cobalt, they were leached remarkably faster when copper leaching recovery exceeded 90%.
Źródło:
Physicochemical Problems of Mineral Processing; 2015, 51, 1; 191-203
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Synergistic solvent extraction of Co(II) and Li(I) from aqueous chloride solutions with mixture of Cyanex 272 and TBP
Autorzy:
Pospiech, B.
Powiązania:
https://bibliotekanauki.pl/articles/110291.pdf
Data publikacji:
2016
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
cobalt(II)
lithium(I)
Cyanex 272
TBP
synergistic extraction
Opis:
In this work, separation of cobalt(II) over lithium(I) ions from aqueous chloride solutions by synergistic solvent extraction (SX) has been studied. A synergistic mixture of commercial extractants such as bis(2,4,4-trimethylpentyl)phosphinic acid (Cyanex 272) and tributyl phosphate (TBP) in kerosene was used as a selective extractant. The investigations were first performed to select optimal conditions for the effective separation including pH of the aqueous phase as well as concentration of synergistic mixture. High selective solvent extraction of cobalt(II) over lithium(I) from chloride solution has been achieved by the mixture of 0.1 M Cyanex 272 and 0.05 M TBP in kerosene while efficient Co(II) stripping has been performed by 0.5 M sulphuric acid.
Źródło:
Physicochemical Problems of Mineral Processing; 2016, 52, 1; 353-364
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Effect of Atomic Layer Deposition of ZrO2 on the Physicochemical Properties of Cobalt based Alloys Intended for Prosthetic Dentistry
Autorzy:
Ziębowicz, A.
Woźniak, A.
Ziębowicz, B.
Kosiel, K.
Chladek, G.
Powiązania:
https://bibliotekanauki.pl/articles/355640.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
cobalt alloy
ZrO2 layer
SFE
corrosion
artificial saliva
Opis:
The paper presents the effect of ZrO2 layer deposition by the ALD process on the physicochemical properties of cobalt-based alloys (Realloy C and EOS CoCr SP2) intended for application in prosthetic dentistry. The paper shows the results of the surface roughness measurements made by the AFM method as well as the wettability and free surface energy measurements. Additionally, potentiodynamic tests of pitting corrosion resistance and electrochemical impedance spectroscopy in a solution of artificial saliva were carried out. Tests were carried out on the samples in the initial state and after surface modification with the ZrO2 layer. Based on these results, the usefulness (e.g. enhancement of corrosion resistance and biocompatibility) of the proposed ZrO2 layer on the cobalt alloys was assessed.
Źródło:
Archives of Metallurgy and Materials; 2018, 63, 3; 1077-1082
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Single-piece all-solid-state Co(II) ion-selective electrode for cobalt monitoring in real samples
Autorzy:
Wardak, C.
Grabarczyk, M.
Powiązania:
https://bibliotekanauki.pl/articles/2082867.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Instytut Agrofizyki PAN
Tematy:
cobalt(II) ion-selective electrode
ionic liquids
solid contact
potentiometry
Opis:
A novel single-piece all-solid-state ion-selective electrode for Co2+ determination has been prepared. The PVC membrane was modified by the addition of ionic liquid. The effect of various ionic liquids was studied in detail and improved performance was observed. The best performance exhibited by the electrode was achieved with a membrane containing 1-ethyl- 3-methyl imidazolium chloride, having a slope of 31.8 mV/ decade in a wide concentration range of 1×10-7 – 1×x10-1 mol L-1. The limit of detection was 5.6×10-8 mol L-1. The response time of the proposed sensor was less than 10 s and the lifetime was at least three months. The proposed sensor showed good selectivity towards the Co2+ ion in comparison with some alkali, alkaline earth, transition and heavy metal ions. It was successfully applied for the direct determination of cobalt ions in real sample solution.
Źródło:
International Agrophysics; 2020, 34, 1; 17-24
0236-8722
Pojawia się w:
International Agrophysics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Wpływ recyklingu na strukturę i właściwości wytrzymałościowe odlewniczego stopu kobaltu stosowanego w stomatologii
Effect of recycling on structure and mechanical properties of dental casting cobalt alloy
Autorzy:
Surowska, B.
Beer, K.
Bieniaś, J.
Powiązania:
https://bibliotekanauki.pl/articles/386681.pdf
Data publikacji:
2011
Wydawca:
Politechnika Białostocka. Oficyna Wydawnicza Politechniki Białostockiej
Tematy:
stomatologia
recykling
wytrzymałość
kobalt
stop
stomatology
recycling
strength
cobalt
alloy
Opis:
Pękanie metalowego szkieletu protez częściowych jest dość częstym przypadkiem w protetyce stomatologicznej. Główną przyczyną tego typu uszkodzenia jest niewłaściwa jakość odlewu. Ze względów ekonomicznych producenci stopów dopuszczają stosowanie złomu metalowego jako części wsadu. W pracy dokonano analizy wpływu recyklingu na właściwości mechaniczne i strukturę odlewniczego stopu kobaltu. Zastosowano odlewanie próżniowo-ciśnieniowe do wsadów zawierających 0%, 25% oraz 50% złomu pochodzącego z kanałów wlewowych i stożków odlewniczych stopu CoCrMo. Porównano właściwości mechaniczne i strukturę odlewów. Stwierdzono, że wytrzymałość mechaniczna wszystkich stopów jest niższa niż średnia deklarowana przez producenta. Przełomy mają charakter kruchy, z wyraźnie widoczną strukturą dendrytyczną. Wraz ze wzrostem udziału materiału wtórnie przetapianego rośnie niejednorodność struktury na przekroju poprzecznym próbek oraz gęstość mikropęknięć w objętości dendrytów po próbie rozciągania.
Cracking of the frame partial dentures is frequent case in dental prosthodontics. The wrong quality of cast is the main reason for this type of damage. The alloys producers allow to use the scrap metal as the part of charge on account of economy. In this paper an influence of recycling on mechanical properties and structure of Co-Cr-Mo dental alloy is carried out. The vacuum pressure casting was used. The charges consist of 0%, 25% and 50% of scrap metal from gate assembly. The mechanical properties and microstructure of precision castings was compared. It was found that all casts strength was lower than average one declared by producer. The brittle fractures and dendritic structures was observed. The structure inhomogeneity and density of microcracks inside dendrites after tension test increase along with percentage growth of scrap metal.
Źródło:
Acta Mechanica et Automatica; 2011, 5, 3; 119-123
1898-4088
2300-5319
Pojawia się w:
Acta Mechanica et Automatica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Synthesis and characterization of iron - cobalt nanoparticles embedded in mesoporous silica MCM - 41
Autorzy:
Surowiec, Z.
Wiertel, M.
Budzyński, M.
Gac, W.
Powiązania:
https://bibliotekanauki.pl/articles/147878.pdf
Data publikacji:
2013
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
cobalt
iron
MCM-41 porous silica
Mössbauer effect
superparamagnetic nanoparticles
Opis:
Fe1.xCox/MCM-41 nanocomposite materials were prepared by wet impregnation of the silica mesoporous support with aqueous solution of iron and cobalt salt mixtures. Samples, after calcination, were reduced at 573 K in order to obtain homogeneous distribution of (Fe-Co)3O4 oxide species over the MCM-41 support. Bimetallic systems were achieved through high temperature reduction, carried out at 1073 K. The temperature-programmed reduction studies indicated complex nature of the oxide species. The phase analysis of the obtained samples after low temperature reduction process carried out by means of X-ray diffraction method and using 57Fe Mossbauer spectroscopy revealed the presence of nanostructured magnetite- and maghemite-like phases. The samples with higher cobalt contents (x . 0.2) contained additionally bimetallic phases. The complete transformation of oxide phases to bimetallic Fe-Co systems occurred during reduction process in hydrogen at 1073 K. It was observed that high temperature processing caused partial transformation of highly dispersed iron oxide nanocrystallites into fayalite species embedded in the silica walls.
Źródło:
Nukleonika; 2013, 58, 1; 87-92
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electrocatalytical Properties of Palladium-Decorated Cobalt Coatings Obtained by Electrodeposition and Galvanic Displacment
Autorzy:
Skibińska, K.
Kutyła, D.
Kołczyk, K.
Kwiecińska, A.
Kowalik, R.
Żabiński, P.
Powiązania:
https://bibliotekanauki.pl/articles/354000.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
linear voltammetry
electrodeposition
palladium
cobalt
galvanic displacement reaction
catalytic activity
Opis:
This work presents the studies on the electrochemical process of thin palladium layers formation onto electrodeposited cobalt coatings. The suggested methodology consists of the preparation of thick and smooth cobalt substrate via galvanostatic electrodeposition. Cobalt coatings were prepared under different cathodic current density conditions from acidic bath containing cobalt sulphate and addition of boric acid. Obtained cobalt layers were analyzed by x-ray diffraction to determine their phase composition. Freshly prepared cobalt coatings were modificated by the galvanic displacement method in PdCl2 solution, to obtain smooth and compact Pd layer. The comparison of electrocatalytic properties of Co coatings with Co/Pd ones enabled to determine the influence of Palladium presence in cathodic deposits on the hydrogen evolution process.
Źródło:
Archives of Metallurgy and Materials; 2018, 63, 3; 1517-1521
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Kobalt i jego związki nieorganiczne – w przeliczeniu na Co
Cobalt
Autorzy:
Sapota, A.
Daragó, A.
Powiązania:
https://bibliotekanauki.pl/articles/137354.pdf
Data publikacji:
2011
Wydawca:
Centralny Instytut Ochrony Pracy
Tematy:
kobalt
toksyczność
narażenie zawodowe
NDS
cobalt
toxicity
occupational exposure
MAC
Opis:
W większości związków kobalt (Co) występuje na II lub III stopniu wartościowości. Związki kobaltu(III) reagują z różnymi kwasami, tworząc sole, podczas gdy kobalt(II) jest mniej reaktywny. Pierwiastek ten występuje w organizmach żywych i jest zaliczany do mikroelementów oraz jest składnikiem witaminy B12. Kobalt jest stosowany jako składnik stopów stali szybkotnących (stopy zawierające 45 ÷ 50% kobaltu i 25 ÷ 30% chromu), stopów magnetycznie twardych, twardych stopów narzędziowych itp. Związki kobaltu są stosowane do produkcji farb (błękit Thenarda, smalta) i lakierów w przemysłach szklarskim i ceramicznym. W warunkach przemysłowych występuje głównie narażenie na kobalt w postaci dymów i pyłów. Szacuje się, że obecnie w Polsce narażonych na kobalt i jego związki jest około 5000 osób. W 2000 r. w jednym z zakładów województwa śląskiego stwierdzono narażenie pracowników na ponadnormatywne stężenie kobaltu metalicznego (dymy, pyły). Narażonych było 20 osób zatrudnionych przy produkcji gotowych wyrobów metalowych (z wyjątkiem maszyn i innych urządzeń). Natomiast wg danych Głównej Inspekcji Sanitarnej w 2007 r. nie było przekroczeń wartości NDS (0,05 mg/m3) kobaltu metalicznego (dymy i pyły). Nie ma danych w dostępnym piśmiennictwie dotyczących ostrych zatruć kobaltem u ludzi. Zatrucia przewlekłe niezawodowe spowodowane spożyciem dużej ilości piwa z dodatkiem siarczanu kobaltu spowodowały uszkodzenie mięśnia sercowego, zwiększenie liczby czerwonych krwinek (czerwienica) i zaburzenie metabolizmu tarczycy. U ludzi narażonych na kobalt drogą inhalacyjną i dermalną obserwowano alergię i słabe działanie drażniące. Układem krytycznym działania kobaltu jest układ oddechowy, w którym najczęściej obserwowano zmiany o typie astmatycznym i podłożu alergicznym, a także zmiany czynnościowe polegające na upośledzeniu wydolności oddechowej. Na podstawie wyników badań toksyczności ostrej kobalt i jego związki nieorganiczne można zaklasyfikować do czynników toksycznych lub szkodliwych. W badaniach przewlekłych główne skutki działania toksycznego kobaltu dotyczyły zmian zapalnych i martwiczych nabłonka dróg oddechowych, a w większych dawkach zmian zwłóknieniowych dolnych partii układu oddechowego. W badaniach wpływu na rozrodczość kobalt wykazywał działanie fetotoksyczne. Badania NTP wykazały działanie rakotwórcze siarczanu kobaltu u myszy i szczurów. IARC zaklasyfikował kobalt i jego związki nieorganiczne do grupy 2B (związki o udowodnionym działaniu rakotwórczym na zwierzęta i nieudowodnionym działaniu rakotwórczym na ludzi). Do ustalenia wartości NDS dla kobaltu i jego związków nieorganicznych za skutek krytyczny przyjęto zmiany astmatyczne w układzie oddechowym o podłożu alergicznym, które manifestowały się kaszlem, świszczącym oddechem oraz spłyceniem oddechu. Zespół tych objawów określa się jako „hard metal asthma”. Większość opisywanych przypadków astmy było związanych z narażeniem na kobalt w przemyśle metali ciężkich. U kilku pacjentów z objawami “hard metal asthma” w badaniach immunolo-gicznych wykazano obecność specyficznych przeciwciał i/lub pozytywny wynik testu transformacji limfocytów. Badania te dotyczyły osób narażonych zarówno na sole kobaltu, jak i metal oraz proszek metalu. Narażenie na pyły kobaltu u pracowników przemysłu metali ciężkich (produkcja metali) oraz w rafine-riach (produkcja kobaltu) wywoływało zmiany czynnościowe w drogach oddechowych polegające na upośledzeniu wydolności oddechowej. Działanie kobaltu na inne narządy i układy, a w szczególności na skórę, układ krążenia, krew oraz tarczycę występowało po znacznie większych dawkach lub stężeniach związku. Z tego względu skutki te pominięto przy ustalaniu wartości dopuszczalnego stężenia kobaltu w powietrzu na stanowiskach pracy. Za postawę do wyznaczenia wartości NDS kobaltu i jego związków nieorganicznych przyjęto wyniki badania przeprowadzonego w Finlandii wśród pracowników zatrudnionych przy produkcji kobaltu. Na podstawie wyników badań stwierdzono, że ryzyko astmy wzrastało 5-krotnie u pracowników narażonych na siarczan kobaltu o stężeniu 0,1 mg/m3 (w przeliczeniu na kobalt). U pracowni-ków narażonych na aerozol siarczanu kobaltu o stężeniach < 0,1 mg/m3 przez 6 ÷ 8 lat nie wykazano wzrostu ryzyka przewlekłego zapalenia oskrzeli.Stężenie kobaltu wynoszące 0,1 mg/m3 przyjęto za wartość LOAEL i przy zastosowaniu odpowiednich współczynników niepewności zaproponowano wartość NDS równą 0,02 mg/m3 zarówno dla kobaltu, jak i jego związków nieorganicznych z uwzględnieniem narażenia na pyły zawierające kobalt. Wartość normatywu higienicznego na tym samym poziomie przyjęto w ACGIH i w Holandii. Mniejszą wartość normatywną kobaltu wynoszącą 0,01 mg/m3 przyjęto w Danii. W Niemczech, ze względu na udowodnione działanie rakotwórcze kobaltu u zwierząt doświadczalnych, nie ustalono dla kobaltu wartości MAK (grupa 3A). Nie było także wystarczających danych do zaproponowania wartości najwyższego dopuszczalnego stężenia chwilowego (NDSCh) kobaltu. Zaproponowano natomiast przyjęcie wartości dopuszczalnego stężenia w materiale biologicznym (DSB) dla stężeń kobaltu w moczu 15 g/l moczu (g/g kreatyniny) i we krwi 1 g/l. Przyjęto także, że normatyw należy oznaczyć literami: ,,I” – sub-stancja o działaniu drażniącym; „A” – substancja o działaniu uczulającym, „Ft” – substancja działa toksycznie na płód oraz „Rakotw.” – kategorię rakotwórczości związków należy ustalić na podstawie wykazu substancji niebezpiecznych wraz z ich klasyfikacją i oznakowaniem, np. dichlorek kobaltu – Rakotw. Kat. 2; R49; siarczan(VI) kobaltu – Rakotw. Kat. 2; R49.
In most compounds, cobalt (Co) occurs at level II or level III of its value. Co compounds (III) react with different acids, producing salts, whereas the reactivity of Co II is less pronounced. This element, present in living organisms, is a microelement and is a component of vitamin B12. It is an essential component of alloys used in high-speed-cutting steel tools (alloys containing 45–50% of Co and 25–30 % of chromium), hard magnets, hard tools and others. Co compounds are used in the production of paints (Thénard blue, smalt) and lacquers in the glass-making and ceramic industries. In industrial conditions, fumes and dusts are the major sources of exposure. It is estimated that in Poland about 5000 persons are exposed to cobalt and its compounds. In 2000, an excessive exposure of workers to metallic Co (fumes and dusts) was found in a plant in the Silesian voivodeship. Twen-ty persons involved in the manufacture of ready-made metallic products (except for machines and other devices) were exposed; however, according to 2007 data provided by the Chief Sanitary In-spectorate, Co (fumes and dusts) maximum admissible concentrations (MAC = 0.05 mg/m3) were not exceeded. In the literature there are no data on Co acute intoxications in humans. Non-occupational chronic intoxications due to consumption of large quantities of cobalt sulfate fortified beer induced myocar-dial lesion, enhanced red blood cell count (polycythemia) and disturbed thyroid metabolism. In persons exposed to cobalt via inhalation and absorption through the skin, allergies and irritations are observed. The respiratory tract is its major target organ, hence asthma- and allergy-like lesions, as well as functional changes, involving the impairment of lung functions are most frequent. On the basis of the results of acute toxicity studies, cobalt and its inorganic compounds can be classi-fied as toxic or hazardous agents. Studies of chronic effects showed that inflammatory and necrotic lesions of respiratory epithelium are the main consequences of cobalt toxicity, and fibrosis of the lower parts of the respiratory tract can also be induced in the case of higher doses. The National Toxicology Program studies have evidenced carcinogenic effect of cobalt sulfate and the Internation-al Agency for Research on Cancer (IARC) has categorized cobalt and its compounds as group 2B (sufficient evidence of carcinogenicity in experimental animals and inadequate evidence in humans). To determine MAC values for cobalt and its inorganic compounds, allergic asthma lesions mani-fested by wheezing cough and shortness of breath were adopted as a critical effect. The syndrome comprising these manifestations is termed hard metal asthma. Most reported asthma cases were linked with exposure to cobalt in the heavy metal industry. In several cobalt-exposed patients with symptoms of hard metal asthma, immunological tests revealed the presence of specific antibodies and/or positive lymphocyte transformation test. Those persons had been exposed to cobalt salts, metallic cobalt and metallic powder. Exposure to cobalt dust in workers employed in the hard metal industry (metal production) and refineries (cobalt production) induced changes in respiratory functions, involving the impairment of 94 respiration efficiency. Co effects on other organs and systems, in general, and on the skin, circulatory system and thyroid gland, in particular, have been observed after higher doses or higher compound concentrations. That is why these effects have been disregarded in setting MAC values in the workstation ambient air. The results of a Finnish study carried out in workers engaged in cobalt production have been adopted as a basis for setting MAC values for cobalt and its inorganic compounds. These find-ings evidenced a five-fold increase in asthma incidence in workers exposed to Co sulfate at a concentration of 0.1 mg/m3 (converted into cobalt). In workers exposed to cobalt sulfate aerosol at a concentration of < 0.1 mg/m3 for 6 – 8 years no enhanced risk of chronic bronchitis has been found. Cobalt concentration of 0.1 mg/m3 has been adopted as the value of the lowest observed adverse effect level (LOAEL) and applying relevant uncertainty coefficients MAC value = 0.02 has been pro-posed for cobalt and its inorganic compounds, taking account of exposure to cobalt-containing dusts. The hygiene standard value at the same level was adopted by the American Conference of Govern-mental Industrial Hygiene (ACGIH) and in The Netherlands. A lower value (0.01 mg/m3) was adopted in Denmark. In Germany, the MAC value for cobalt has not been set on account of its suffi-ciently evidenced carcinogenicity in experimental animals (group 3A). Moreover, the data were in-sufficient to propose a short-term MAC (STMAC) value for cobalt. However, it has been suggested to adopt the value of admissible concentration in biological material (ACB) for Co concentration in urine, 15 μg/l urine (μg/g creatinine) and in blood, 1μg/l. The following standard denotations have been adopted: “I” – irritating substance; “A” – sensitizing substance; “Ft” – fetus toxic substance; and “Carcinogenic” – the category of carcinogenicity of compounds should be determined on the basis of the list of hazardous substances along with its classification and denotation, e.g., cobalt dich-loride – Carcinogenic, Cat. 2; R49; cobalt sulfate (VI) – Carcinogenic, Cat. 2; R49.
Źródło:
Podstawy i Metody Oceny Środowiska Pracy; 2011, 3 (69); 47-94
1231-868X
Pojawia się w:
Podstawy i Metody Oceny Środowiska Pracy
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Recovery of cobalt ions from diluted solutions by means of protonated dry alginate beads
Autorzy:
Aracena, Alvaro
Padilla, Sebastián
Jerez, Oscar
Powiązania:
https://bibliotekanauki.pl/articles/110037.pdf
Data publikacji:
2019
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
recovery mechanism
cobalt ions
alginate beads
kinetic adsorption model
elution
Opis:
Mining effluents contain cobalt ions that can damage humans and flora. However, this meta also has high commercial value when recovered. The objective of this research work was to recover cobalt (Co2+) from diluted solutions using a biosorbent, specifically protonated dry alginate beads (PDAB). Experimental work was carried out in batch from an initial concentration of 22×10-6 kg dm-3 Co2+ and 80 mg alginate. Variables such as agitation, pH solution, experimental time, isotherm values, and temperature were analyzed. Maximum cobalt recoveries were obtained at pH values above 5.0, reaching 60.6×10-3 kg kg-1 of PDAB. Cobalt recovery occurred with ion exchange mechanisms from alginate carboxyl group proton release. Experimental data had excellent fit with both the Lagergren kinetic model (pseudo-first order) and the Langmuir isotherm model. As temperature increased, cobalt recovery increased. The calculated activation energy was 12.8 kJ mol-1. Compositional measurements obtained by scanning electron microscope and energy-dispersive X-ray spectroscopy for alginate crosssections showed uniform distributions of cobalt concentrations throughout the spherical alginate structure, independent of solution pH, contact time, or temperature. Furthermore, elution gave significant cobalt re-extraction (98.2%) and demonstrated PDAB reusability.
Źródło:
Physicochemical Problems of Mineral Processing; 2019, 55, 5; 1286-1297
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mineralogy and in situ S and Pb isotope characteristics of ore minerals from polymetallic mineralization in the Gierczyn-Przecznica area, SW Poland
Autorzy:
Foltyn, Krzysztof
Kozub-Budzyń, Gabriela Anna
Lahaye, Yann
Piestrzyński, Adam
Skirak, Paulina
Zygo, Władysław
Pieczonka, Jadwiga
Powiązania:
https://bibliotekanauki.pl/articles/27323311.pdf
Data publikacji:
2023
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
Pb isotopes
S isotopes
polymetallic mineralization
cobalt
ore geology
Sudety Mts.
Opis:
Chlorite-mica-quartz schist in the Gierczyn-Przecznica area in SW Poland contains polymetallic ores which were the source of tin and cobalt in the past. This mineralogical study revealed the presence of silver-bearing minerals including members of the tetrahedrite (Ag <3 apfu) and freibergite series (3 < Ag < 8 apfu), galena (0.26–1.48 wt.% Ag), and a phase with the chemical composition of Te-rich canfieldite Ag8Sn(S,Te)6. In Przecznica Sn-sulphides are represented by stannite while cobaltite is the most abundant host for cobalt, followed by Co-bearing arsenopyrite. Glaucodot, ullmannite and members of the löllingite-rammelsbergite solid-solution series (Fe,Ni,Co)As2 also contain cobalt but are scarce in the samples. An exposure in the “Psi Grzbiet” area is characterized by the presence of Ag, Ni, Sb and Te minerals accompanied by very small amounts of As-bearing phases (represented by arsenopyrite) while the mineralogical composition in the Przecznica area is characterized by an abundance of As phases and a lack of Sb minerals. Sulphur isotopes of sulphides from Przecznica are heavier than in most deposits related to the Karkonosze Granite intrusion, while their Pb isotope signature in galena suggests an Early Paleozoic pre-Variscan affinity rather than a Variscan one.
Źródło:
Geological Quarterly; 2023, 67, 1; art. no. 10
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Wpływ technologii wytwarzania na właściwości materiałowe stopu kobaltu wykorzystywanego w protetyce dentystycznej
The effects of production technology on cobalt alloy material properties used in dental techniques
Autorzy:
Litwinko, M.
Grądzka-Dahlke, M.
Powiązania:
https://bibliotekanauki.pl/articles/99335.pdf
Data publikacji:
2014
Wydawca:
Politechnika Śląska. Katedra Biomechatroniki
Tematy:
stop kobaltu
protetyka dentystyczna
odlewnictwo
SLM
cobalt alloy
prosthetic dentistry
foundry
Opis:
Jednym z etapów w procesie powstawania protetycznego uzupełnienia dentystycznego jest realizacja zaprojektowanego kształtu protezy w tworzywie metalowym. Jest krokiem istotnym a zarazem narażonym na wiele niepowodzeń. W artykule przedstawiono porównanie dwóch metod wykonawstwa techniki dentystycznej: tradycyjnego odlewania oraz nowoczesnej SLM. Badaniom poddano protetyczny stop kobaltu w postaci prostopadłościennych próbek.
One of the stages in the process of restoration of dental prostheses is the shape which was designed to achieve a complement in the metal. It is an important step and exposed to many setbacks. The article gives a comparison of two methods of dental technology: traditional casting and modern SLM. The test was in the form of a cobalt alloy prosthetic square bales samples.
Źródło:
Aktualne Problemy Biomechaniki; 2014, 8; 99-102
1898-763X
Pojawia się w:
Aktualne Problemy Biomechaniki
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of heavy metals on living organisms
Autorzy:
Draszawka – Bołzan, Beata
Powiązania:
https://bibliotekanauki.pl/articles/1194070.pdf
Data publikacji:
2014
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
heavy metals
soil
iron
zinc
copper
manganese
cobalt
mercury
lead
cadmium
Opis:
The rapid development of technology and the changes that are occurring in the world today largely affect on the environment. One of the primary sources of pollution of the biosphere are industrial plants, which emit both gaseous substances (eg. Carbon monoxide, sulfur and nitrogen) and dust, containing all sorts of toxic substances. For the serious consequences of the development of civilization and industry should be spread include heavy metals. Included in the atmosphere, dust and heavy metals fall to the ground parts of plants and enters the soil. Shall be collected by the roots of plants or animals grazing on the roads and thus incorporated into the food chain. These elements are not biodegradable. They are indestructible and indelible. Once released into the environment continuously circulate therein, changing, at most its shape. Heavy metals are ubiquitous and can be detected in every organic material and in every living organism. They are a particular threat to humans.
Źródło:
World Scientific News; 2014, 5; 12-20
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Biosynthesis of cobalt oxide (Co3O4) nanoparticles using plant extract of Camellia sinensis (L.) Kuntze and Apium graveolens L. as the antibacterial application
Autorzy:
Urabe, Aliyaa A.
Aziz, Wisam J.
Powiązania:
https://bibliotekanauki.pl/articles/1076785.pdf
Data publikacji:
2019
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Apium graveolens
Camellia sinensis
Cobalt oxide nanoparticles
Pseudomonas aeruginosa
Staphylococcus aureus
Opis:
In this work, we prepared cobalt oxide nanoparticles using Celery stalks and green tea leaves extract. The synthesized cobalt-oxide NPs were characterized using X-Ray diffraction. This showed the highest peak and top control (222) at (38.18 degree) with regard to Camellia sinensis extract and (220) at (30.14 degree) for Apium graveolens extract, Field Emission scanning electron microscopy (EF_SEM) at the range of 21-72 nm, revealed the highly uniform shape of particles, while UV-Visible spectroscopy techniques recorded the highest value of the absorptive at 230 nm and the energy band gap to be 3.55 eV for Camellia sinensis and 225 nm and energy band gap 3.85 eV at Apium graveolens, respectively. Our results indicate that the best achievable result in inhibiting bacteria such as Staphylococcus aureus and Pseudomonas aeruginosa comes by way of using Camellia sinensis extract (27-29 mm).
Źródło:
World News of Natural Sciences; 2019, 24; 356-364
2543-5426
Pojawia się w:
World News of Natural Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł

Ta witryna wykorzystuje pliki cookies do przechowywania informacji na Twoim komputerze. Pliki cookies stosujemy w celu świadczenia usług na najwyższym poziomie, w tym w sposób dostosowany do indywidualnych potrzeb. Korzystanie z witryny bez zmiany ustawień dotyczących cookies oznacza, że będą one zamieszczane w Twoim komputerze. W każdym momencie możesz dokonać zmiany ustawień dotyczących cookies