Статті в журналах: "Medium manganèse"

1

Новохацкая, А. А., та Г. Я. Акимов. "Роль избыточного марганца в формировании структуры и транспортных свойств манганита (Nd-=SUB=-0.67-=/SUB=-Sr-=SUB=-0.33-=/SUB=-)-=SUB=-1-x-=/SUB=-Mn-=SUB=-1+x-=/SUB=-О-=SUB=-3-=/SUB=- (x=0; 0.2), спеченного при 1273-1473 K". Физика твердого тела 60, № 7 (2018): 1378. http://dx.doi.org/10.21883/ftt.2018.07.46127.009.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

Анотація:

AbstractThe Nd_0.67Sr_0.33MnO_3 manganite is a material promising for application as a cathode for medium-temperature solid oxide fuel elements. A high electrical conductivity of such a cathode is the parameter determining the efficiency of the operation of a fuel element. In this report, the effect of influence of excess manganese on the structure and the conductivity of manganite ceramics with compositions (Nd_0.67Sr_0.33)_1– x Mn_1 + x O_3± Δ ( x = 0, 0.2) sintered at temperatures 1273–1673 K is presented for the first time. The existence of 20% excess manganese in the initial manganite powder after sintering is shown to lead to that the conductivity of the obtained ceramics in the temperature range 823–1073 K is several times higher than the conductivity of the ceramics without excess manganese.

2

Francisco Sánchez Viesca and Reina Gómez Gómez. "A complete and sustained organic/inorganic reaction mechanism of Baeyer’s test." World Journal of Chemical and Pharmaceutical Sciences 4, no. 2 (May 30, 2024): 001–5. http://dx.doi.org/10.53346/wjcps.2024.4.2.0023.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

Анотація:

The Baeyer’s test for unsaturation has been used in Qualitative Organic Analysis for a long time. However, if an alkaline reagent is used, compounds having an active hydrogen (carbon acids) also give a positive test with potassium permanganate, detracting the test for unsaturation. The first steps of the reaction sequence have been described but the next stages are missing. These are very important because they involve the formation mode of the observed end product, brown manganese dioxide. In this communication, a complete and sustained reaction mechanism is provided for both reaction mediums, neutral and alkaline. It is in accordance with observed experimental facts. The missing steps are a redox reaction between hypomanganate and permanganate ions, and a second cyclic intermediate now formed with manganate ion. The instability of this intermediate leads directly to manganese dioxide and alkalinization of the neutral medium, as observed experimentally.

3

Wang Yanjie, 王艳杰, 赵琳 Zhao Lin, 彭云 Peng Yun та 曹洋 Cao Yang. "中锰汽车钢激光焊接焊缝组织与韧性". Chinese Journal of Lasers 49, № 8 (2022): 0802021. http://dx.doi.org/10.3788/cjl202249.0802021.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

4

De Moor, Emmanuel, Alexandra Glover, Josh Mueller, John G. Speer, and David K. Matlock. "Double Soaking of Medium Manganese Steels." Materials Science Forum 1105 (November 29, 2023): 207–12. http://dx.doi.org/10.4028/p-wh9qva.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

Анотація:

Double soaking (DS) has been proposed as an alternate processing route for medium manganese steels. DS consists of soaking in the intercritical annealing region to stimulate manganese enrichment of austenite by depletion of ferrite followed by secondary soaking at a higher temperature and cooling to room temperature to obtain a martensite/austenite microstructure. DS is different from more traditional medium manganese heat treating which usually involves a single soaking step in the intercritical region to generate a ferrite/austenite microstructure. DS has been shown effective at generating attractive tensile properties notably tensile strength levels in excess of typically observed levels in medium manganese steels. A review of properties and microstructural evolution obtained by DS of medium manganese steels is presented here.

5

Chakraborty, D., and T. K. Baidya. "Multi-Phase Manganese Mineralization in the Noamundi Synclinorium, East Indian Shield." Energy and Earth Science 3, no. 1 (May 7, 2020): p26. http://dx.doi.org/10.22158/ees.v3n1p26.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

Анотація:

Manganese mineralization associated with phyllites in and around Joda, Odisha belongs to the Iron Ore Group of Noamundi basin and is a part of Jamda-Koira belt of East Indian Shield. The present study area comprises low to medium grade tectonites containing economic resources of both iron and manganese. Present study is concentrated on Manganese mineralization. Field study and petro-mineralogical observations reveal syngenetic character of manganese ores comprising lowT higher oxides viz. pyrolusite, cryptomelane, manganite as major Mn-minerals along with highT lower oxides viz. jacobsite, bixbyite, braunite and hausmannite as minor Mn-minerals. The Mn-ore bodies and associated phyllites have undergone multiple phases of deformation and metamorphism followed by hydrothermal and supergene processes. Four deformational phases have been deciphered during field study. Geochemical analyses of ores and phyllitic host rocks show high values of Al2O3, TiO2, Ba, Co, Ni, Cr, Cu, Sc, V, As, Zn but depletion of Sr, Yb, Sm, Nb. Geochemical data infer ores to be a recycling product originally derived from a mafic crustal source of tholeiitic character. Age data obtained from Sm-Nd ratio of two rock samples are 3.46 Ga and 2.79 Ga. Present work provides a critical assessment on the multiphase mineralization of manganese ores.

6

Karoblis, Dovydas, Aleksej Zarkov, Tomas Murauskas, and Aivaras Kareiva. "Molten Salt Synthesis of Micro-Sized Hexagonally Shaped REMnO3 (RE = Y, Er, Tm, Yb)." Inorganics 11, no. 5 (April 23, 2023): 178. http://dx.doi.org/10.3390/inorganics11050178.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

Анотація:

Yttrium manganite (YMnO3) is a compound belonging to the hexagonal rare earth manganites family, which demonstrates multiferroic properties. This material can be prepared by several synthetic approaches, with the most common one being the solid-state synthesis. In this work, we show a possibility of preparing this material via molten salt synthesis using the NaCl-KCl mixture as the reaction medium and yttrium and manganese nitrates as the starting materials. We demonstrate that, by varying the reaction temperature and the nitrates-to-chlorides ratio, it is feasible to synthesize hexagonally shaped particles of microscopic dimensions. A similar synthesis procedure can be successfully applied for the preparation of other hexagonal manganites—ErMnO3, TmMnO3, and YbMnO3.

7

Ito, Atsushi, Akinobu Shibata, and Nobuhiro Tsuji. "Thermomechanical Processing of Medium Manganese Steels." Materials Science Forum 879 (November 2016): 90–94. http://dx.doi.org/10.4028/www.scientific.net/msf.879.90.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

Анотація:

As third generation advanced high strength steels (AHSS) managing both high strength and good ductility/formability, medium manganese steels containing 3-7 wt% Mn have attracted attentions recently. However, the fundamental microstructure evolution during thermomechanical processing and heat treatments in medium-Mn steels is still unclear. In the present study, changes in microstructure and mechanical properties during various heat treatments and thermomechanical processes of 4Mn-0.1%C steel were studied. It was clarified from dilatometric measurements that ferrite transformation in the 4Mn-0.1C steel was quite slow, so that fully martensitic structures were obtained in many cases after cooling from austenite. On the other hand, hot-deformation of austenite greatly accelerated ferrite transformation, and dual phase microstrcutures composed of ferrite and martensite could be obtained. The dual phase steel showed good combinations of high strength and adequate tensile ductility.

8

Rana, Radhakanta. "Special issue on ‘Medium manganese steels’." Materials Science and Technology 35, no. 17 (October 10, 2019): 2039–44. http://dx.doi.org/10.1080/02670836.2019.1673971.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

9

Lee, Y. K., and J. Han. "Current opinion in medium manganese steel." Materials Science and Technology 31, no. 7 (November 26, 2014): 843–56. http://dx.doi.org/10.1179/1743284714y.0000000722.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

10

Farkas, Bence, Marek Bujdoš, Filip Polák, Michaela Matulová, Martin Cesnek, Eva Duborská, Ondřej Zvěřina, et al. "Bioleaching of Manganese Oxides at Different Oxidation States by Filamentous Fungus Aspergillus niger." Journal of Fungi 7, no. 10 (September 28, 2021): 808. http://dx.doi.org/10.3390/jof7100808.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

Анотація:

This work aimed to examine the bioleaching of manganese oxides at various oxidation states (MnO, MnO·Mn2O3, Mn2O3 and MnO2) by a strain of the filamentous fungus Aspergillus niger, a frequent soil representative. Our results showed that the fungus effectively disintegrated the crystal structure of selected mineral manganese phases. Thereby, during a 31-day static incubation of oxides in the presence of fungus, manganese was bioextracted into the culture medium and, in some cases, transformed into a new biogenic mineral. The latter resulted from the precipitation of extracted manganese with biogenic oxalate. The Mn(II,III)-oxide was the most susceptible to fungal biodeterioration, and up to 26% of the manganese content in oxide was extracted by the fungus into the medium. The detected variabilities in biogenic oxalate and gluconate accumulation in the medium are also discussed regarding the fungal sensitivity to manganese. These suggest an alternative pathway of manganese oxides’ biodeterioration via a reductive dissolution. There, the oxalate metabolites are consumed as the reductive agents. Our results highlight the significance of fungal activity in manganese mobilization and transformation. The soil fungi should be considered an important geoactive agent that affects the stability of natural geochemical barriers.

11

Temmel, C., B. Karlsson, and N. G. Ingesten. "Quenching cracks in medium carbon steel initiated at manganese sulfide inclusions." HTM Journal of Heat Treatment and Materials 62, no. 5 (October 1, 2007): 236–42. http://dx.doi.org/10.1515/htm-2007-0009.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

Анотація:

Abstract Quench crack propensity has been investigated for two identical medium carbon steels (50CrMo4) which only differed in sulfur content. The standard variant of the material was affected by manganese sulfide inclusions whereas the low sulfur material was essentially free of sulfides. 80 mm, cylindrical test specimens were used. The test specimens had been cut out of cross rolled steel plates in which the manganese sulfide were flattened to discoid shape. The specimen orientation was in direction of principal deformation where the flattened sulfides were aligned with the test specimen axis. The largest sulfides reached lengths of 150 μm. Both materials were austenitized at 850 °C for 60 minutes, quenched in a salt-bath at 180 °C and immediately annealed at 425 °C for one hour. It turned out that the standard material developed quench cracks which initiated at manganese sulfide. No cracks could be found in the low sulfur material. Thermal and transformational stresses, which develop during quenching, aggravate the stress situation around the manganese sulfide and cause the cracking. The results are interpreted in fracture mechanical terms.

12

Ryabov, A. V. "Medium-Carbon Free-Cutting Steel." Materials Science Forum 946 (February 2019): 47–52. http://dx.doi.org/10.4028/www.scientific.net/msf.946.47.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

Анотація:

The paper presents theoretical and experimental studies of the formation processes of boron nitride, aluminium nitride, aluminium oxide and manganese sulphide inclusions in a free-cutting steel. Fact Sage software was used to model the behaviour of non-metallic inclusions. Formation temperatures and the amount of key inclusions in steel were calculated. Formation order of inclusions is as follows: aluminium oxide > boron nitride > manganese sulphide > aluminium nitride. The object of study was the A45AR grade steel in 1.1–1.2 kg ingots. It was melted in an induction furnace, and aluminium, nitrided ferrosilicon and ferroboron were added after deoxidation before tapping. Quality estimation included chemical composition, macro-and microstructure, the character and shape of non-metallic inclusions. The finished metal contained fine and uniformly distributed inclusions of boron nitride. Qualitative and quantitative analysis of boron nitrides distribution in metal matrix showed that they were present both as individual and complex compounds, mostly of spherical shape. The size of BN inclusions varied from 0.18 to 6.52 μm. The amount of boron added to steel did not affect the size of MnS non-metallic inclusions.

13

Niven, Donald F., Andrew Ekins, and Aws A.-W. Al-Samaurai. "Effects of iron and manganese availability on growth and production of superoxide dismutase byStreptococcus suis." Canadian Journal of Microbiology 45, no. 12 (December 1, 1999): 1027–32. http://dx.doi.org/10.1139/w99-114.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

Анотація:

A complex medium supported good growth of the type strain of Streptococcus suis irrespective of the presence or absence of a high concentration (1 mM) of the iron chelating agent, ethylenediamine di-o-hydroxyphenylacetic acid. Good growth was also obtained using a complex medium that had been treated with Chelex-100 to reduce the iron content, but only if this medium was supplemented with manganese; supplementation with iron had little effect. Collectively, these results indicate that S. suis requires manganese, but not iron, for growth. Polyacrylamide gel electrophoresis of cell extracts followed by activity staining revealed the presence of a single manganese-cofactored superoxide dismutase; activity staining and enzyme assays revealed that manganese availability during growth affected the activity of the superoxide dismutase in cell extracts. The results are discussed with respect to the capacity of S. suis to avoid damage by reactive oxygen species.Key words: Streptococcus suis, iron, manganese, superoxide dismutase.

14

Tazwar, Gajala, and Vijay Devra. "Soluble Colloidal Manganese Dioxide: Formation, Characterization and Application in Oxidative Kinetic Study of Ciprofloxacin." Bulletin of Chemical Reaction Engineering & Catalysis 15, no. 1 (September 13, 2019): 74–83. http://dx.doi.org/10.9767/bcrec.15.1.5436.74-83.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

Анотація:

Soluble colloidal manganese dioxide was formed by reduction of potassium permanganate with sodium thiosulphate in neutral aqueous medium at 25 ºC. The obtained nano-sized colloidal manganese dioxide was found to be dark reddish-brown in color and stable for several months. The formation of manganese dioxide was confirmed by UV-visible spectrophotometer and determination of oxidation state of Mn species in manganese dioxide. The effect of different concentration of sodium thiosulphate on the formation of manganese dioxide was also studied. The nano-sized colloid manganese dioxide was characterized by transmission electron microscopy and Fourier transform infrared spectrophotometer. The formed soluble colloidal manganese dioxide was used as an oxidant in oxidation of ciprofloxacin in perchloric acid medium at 35 ºC. The reaction was first-order concerning to concentration of manganese dioxide and hydrogen ion but fractional order with ciprofloxacin. The results suggest formation of complex between ciprofloxacin and manganese dioxide. The oxidation products were also identified based on stoichiometric and characterization results. Copyright © 2020 BCREC Group. All rights reserved

15

Morawiec, M., V. Ruiz-Jimenez, C. Garcia-Mateo, and A. Grajcar. "Thermodynamic analysis and isothermal bainitic transformation kinetics in lean medium-Mn steels." Journal of Thermal Analysis and Calorimetry 142, no. 5 (October 9, 2020): 1709–19. http://dx.doi.org/10.1007/s10973-020-10259-z.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

Анотація:

AbstractThe work presents the results of thermodynamic analysis of two medium manganese steels with different Mn contents. The steels containing 3.1 and 3.6% of manganese were subjected to theoretical thermodynamic calculations using MUCG83 software and dilatometric experiments. The steels were heat-treated in two different isothermal holding temperatures of 400 and 350 °C for 15 min. The bainite transformation kinetics at different temperatures for different manganese contents was investigated. In the steel including 3.1% Mn, a complete transformation was obtained. The results indicated a strong influence of the holding temperature on the kinetics of bainitic transformation. It was related to the driving force of this process. When the manganese content was increased by 0.5%, an incomplete bainite transformation occurred. The microstructure investigations after heat treatment were performed using light and scanning electron microscopy. The XRD analysis to determine retained austenite amount and its carbon enrichment was performed. The microstructure of 3MnNb steel consisted of bainite and retained austenite with filmlike and blocky morphologies. The steel with the higher Mn content contained also fresh martensite for both isothermal holding temperatures.

16

Fisher, Carolyn R., Elizabeth E. Wyckoff, Eric D. Peng, and Shelley M. Payne. "Identification and Characterization of a Putative Manganese Export Protein in Vibrio cholerae." Journal of Bacteriology 198, no. 20 (August 1, 2016): 2810–17. http://dx.doi.org/10.1128/jb.00215-16.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

Анотація:

ABSTRACTManganese plays an important role in the cellular physiology and metabolism of bacterial species, including the human pathogenVibrio cholerae. The intracellular level of manganese ions is controlled through coordinated regulation of the import and export of this element. We have identified a putative manganese exporter (VC0022), namedmneA(manganeseexporterA), which is highly conserved amongVibriospp. AnmneAmutant exhibited sensitivity to manganese but not to other cations. Under high-manganese conditions, themneAmutant showed an almost 50-fold increase in intracellular manganese levels and reduced intracellular iron relative to those of its wild-type parent, suggesting that the mutant's manganese sensitivity is due to the accumulation of toxic levels of manganese and reduced iron. Expression ofmneAsuppressed the manganese-sensitive phenotype of anEscherichia colistrain carrying a mutation in the nonhomologous manganese export gene,mntP, further supporting a manganese export function forV. choleraeMneA. The level ofmneAmRNA was induced approximately 2.5-fold after addition of manganese to the medium, indicating regulation of this gene by manganese. This study offers the first insights into understanding manganese homeostasis in this important pathogen.IMPORTANCEBacterial cells control intracellular metal concentrations by coordinating acquisition in metal-limited environments with export in metal-excess environments. We identified a putative manganese export protein, MneA, inVibrio cholerae. AnmneAmutant was sensitive to manganese, and this effect was specific to manganese. ThemneAmutant accumulated high levels of intracellular manganese with a concomitant decrease in intracellular iron levels when grown in manganese-supplemented medium. Expression ofmneAintranssuppressed the manganese sensitivity of anE. coli mntPmutant. This study is the first to investigate manganese export inV. cholerae.

17

Pickard, M. A., H. Vandertol, R. Roman, and R. Vazquez-Duhalt. "High production of ligninolytic enzymes from white rot fungi in cereal bran liquid medium." Canadian Journal of Microbiology 45, no. 7 (August 1, 1999): 627–31. http://dx.doi.org/10.1139/w98-233.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

Анотація:

White rot fungi from the University of Alberta Mold Herbarium, identified as able to degrade aromatics from a study of PCB metabolism, were examined for production of ligninolytic enzymes. Production of lignin peroxidase, manganese peroxidase, laccase, and veratryl alcohol oxidase were monitored during growth in different media. Good growth but low enzyme production occurred in a glucose - malt extract - yeast extract medium. Media containing 2% cereal bran in 60 mM phosphate buffer supported high levels of laccase production, up to 13 000 U/L in Coriolopsis gallica UAMH 8260 and manganese peroxidase activity up to 1100 U/L in Bjerkandera adusta UAMH 8258. Cereal bran media supported higher laccase production than 2,5-xylidine and higher manganese peroxidase production than a medium containing manganous ion plus veratryl alcohol.Key words: cereal bran, laccase, manganese peroxidase, white rot fungi.

18

Luan, G., O. Volkova, and J. Mola. "Design of Fully Austenitic Medium Manganese Steels." IOP Conference Series: Materials Science and Engineering 373 (June 2018): 012002. http://dx.doi.org/10.1088/1757-899x/373/1/012002.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

19

Messaoudi, Bouzid, Suzanne Joiret, Michel Keddam, and Hisasi Takenouti. "Anodic behaviour of manganese in alkaline medium." Electrochimica Acta 46, no. 16 (May 2001): 2487–98. http://dx.doi.org/10.1016/s0013-4686(01)00449-2.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

20

Scott, Colin P. "Recent Developments in Medium and High Manganese Steels." Metals 12, no. 5 (April 27, 2022): 743. http://dx.doi.org/10.3390/met12050743.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

Анотація:

A huge amount of intellectual effort is currently being devoted to the study of medium and high manganese steels due to the diverse and impressive mechanical properties that can be achieved with these steels [...]

21

Al-Maali, G. A., N. A. Bisko, and A. M. Ostapchuk. "The effect of citrate and sulfate of different metals on carbohydrates composition of medicinal mushroom Trametes versicolor (Polyporales, Polyporaceae)." Visnyk of Dnipropetrovsk University. Biology, medicine 7, no. 1 (March 9, 2016): 32–36. http://dx.doi.org/10.15421/021606.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

Анотація:

The aim of our research was to study the influence of citrate and sulfate of copper, manganese and zinc on the carbohydrates composition of biomass of the medicinal mushroom Trametes versicolor (L.) Lloyd. cultivated in a liquid medium. The studied strain of Trametes versicolor 353 was obtained from the Culture Collection of Mushrooms (IBK) from the M. G. Kholodny Institute of Botany, National Academy of Sciences of Ukraine. Citrates of copper, manganese and zinc were obtained from the Institute of Nanobiotechnologies and Resource Conservation of Ukraine, Kyiv. In this study we used glucose-peptone-yeast extract medium (GPY) with the following composition of (g/L): glucose – 25, peptone – 3, yeast extract – 3, K2HPO4 – 1, KH2PO4 – 1, MgSO4 ∙ 7H2O – 0.25, distilled water – 1,000 ml; pH 6,5 (control medium). Cu2+ (sulfate form or citrate form) were added to control medium in concentration 4 mg/L, Zn2+ and Mn2+ (sulfate form or citrate form) were added to control medium in concentration 1 mg/L. Mycelium was grown in a submerged culture on a rotary shaker (120 rpm) at 26 °C in 250 ml Erlenmeyer flasks, containing 50 ml of liquid medium. The biomass was harvested after 9 days of cultivation in the liquid medium. Monosaccharides and sugar alcohols was analyzed by high-performance liquid chromatography Agilent 1200 (Agilent technologies, USA). The results of our research demonstrated that the fraction of total carbohydrates from T. versicolor 353, which were cultivated on the control medium, consists of glucose (91.5%), galactose (1.9%), mannose (5.4%), fucose (0.6%) and xylose (0.7%). The adding of sulfate of zinc or copper to the liquid medium didn’t change the content of monosaccharides of T. versicolor 353 biomass relative to the control medium. At the same time, in the medium with citrate of zinc the amount of glucose increased and the amount of mannose decreased relative to the control medium. Xylose and fucose were not detected in this case. In mycelium of T. versicolor 353 that was cultivated in the medium with manganese sulfate or manganese citrate we detected a small amount of ribose. But the content of other monosaccharides didn’t change in the medium with sulfate of manganese. At the same time, the addition of citrate of manganese to the medium raised the amount of mannose and reduced the amount of glucose in the biomass of T. versicolor 353 relative to the control medium. Also copper citrate reduced the content of glucose in mycelium of T. versicolor 353 relative to the control medium. But in this case we detected mannitol and sorbitol in the biomass. This data indicates that synthesis of sugur alcohols in T. versicolor 353 depend on copper ions in bioactive forms of citrate.

22

Gramlich, A., M. A. Auger, and S. Richter. "Plasma Nitriding of an Air-Hardening Medium Manganese Forging Steel." HTM Journal of Heat Treatment and Materials 77, no. 4 (August 1, 2022): 298–315. http://dx.doi.org/10.1515/htm-2022-1017.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

Анотація:

Abstract The impact of plasma nitriding on the microstructure and the hardness of a recently developed 4 wt.-% medium manganese steel are presented. In contrast to standard quench and tempering steels, the investigated material achieves its martensitic microstructure by air-cooling from the forging heat, which enables the reduction of the carbon footprint of the forged components. The influence of nitriding on this grade of steel has not been investigated so far, but fundamental differences in comparison to standard nitriding steels are expected due to the increased manganese concentration. To address this issue, nitriding treatments with different temperatures (350 °C, 580 °C and 650 °C) have been performed, followed by examinations of the microstructure, the phase composition, the obtained hardness profiles and the tensile properties of the bulk material after nitriding, accompanied by thermodynamic equilibrium calculations. It is demonstrated that after nitriding at 580 °C similar hardness profiles like standard nitriding steels are achieved, with a shorter process as austenitization and hardening were omitted, reaching a hardness of approximately 950 HV0.1. Furthermore, it was demonstrated that austenite can be stabilized by manganese and nitrogen partitioning to room temperature during nitriding in the intercritical phase region.

23

Ali, M. "Tertiary enrichment of a manganese oxide tailings material using heavy medium separation (HMS)." Bangladesh Journal of Scientific and Industrial Research 49, no. 1 (May 8, 2014): 35–40. http://dx.doi.org/10.3329/bjsir.v49i1.18852.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

Анотація:

A study was conducted on the enrichment of manganese oxide tailings material generated from sorting spiral concentration at Ghana Manganese Company (GMC) Limited, Nsuta. The investigation explored mineralogical and particle size characterisation and heavy medium separation technique. Analytical methods used include; X-Ray Fluorescence and Atomic Absorption Spectrometry (AAS). The material contained 9.01% Al2O3, 27.43 % SiO2, 23.64% MnO2 and 9.86% Fe2O3, the other oxides range between 0.04 to 1.55 %. By treating the individual size fractions at a bath density of 2.96, the highest ratio of concentration of 3.56 was obtained at 180 ?m, while the highest enrichment ratio of 1.84 and manganese grade of 38.25% were obtained at 1180?m respectively. These qualify the enriched material as suitable for Ferro-alloy industry. DOI: http://dx.doi.org/10.3329/bjsir.v49i1.18852 Bangladesh J. Sci. Ind. Res. 49(1), 35-40, 2014

24

FALCO, L., A. MARTÍNEZ, M. P. DI NANNO, H. THOMAS, and G. CURUTCHET. "STUDY OF A PILOT PLANT FOR THE RECOVERY OF METALS FROM SPENT ALKALINE AND ZINC-CARBON BATTERIES WITH BIOLOGICAL SULPHURIC ACID AND POLYTHIONATE PRODUCTION." Latin American Applied Research - An international journal 44, no. 2 (April 30, 2014): 123–29. http://dx.doi.org/10.52292/j.laar.2014.429.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

Анотація:

The recovery of Zn and Mn from spent alkaline and Zn-C batteries with a biohydrometallurgycal process was studied in a pilot plant that consists of an air-lift bioreactor with a sulphur packed bed where Acidithiobacillus thiooxidans produces an acid-reducing medium; a leaching reactor where the acid-reducing medium is mixed with the battery powder, and a recovery reactor where metals are recovered from the leaching liquor by electrolysis. Results show that with acid medium (350 mM[H+]) produced in 12 days by Acidithiobacillus thiooxidans in the bioreactor, an extraction of 100% of Zn and 67% of the Mn present in the battery powder was reached. The presence of polythionates in the medium produced in the bioreactor allows the dissolution of the manganese. The solid remaining after bioleaching is a manganese oxide. The electrolysis of the leaching liquor produced a cathodic deposit of metallic Zn and an anodic deposit of a manganese oxide in one step at room temperature.

25

Hou, Fei Fei, Atsushi Ito, Yu Bai, Akinobu Shibata, and Nobuhiro Tsuji. "Microstructure Evolution and Change in Mechanical Properties of Medium Mn Steels during Thermomechanical Processing." Materials Science Forum 941 (December 2018): 346–51. http://dx.doi.org/10.4028/www.scientific.net/msf.941.346.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

Анотація:

Medium manganese steels are nowadays energetically investigated as the third generation advanced high strength steels (AHSS) because of their excellent balance between material cost and mechanical properties. However, the phase transformation and microstructure evolution in medium manganese steels during various heat treatments and thermomechanical processing are still unclear. The present study firstly examined kinetics of static phase transformation behavior and microstructural change in a 3Mn-0.1C medium manganese steel. Hot compression tests were also carried out to investigate the influences of high-temperature thermomechanical processing on the microstructure evolution. It was found that ferrite transformation was quite slow in static conditions but greatly accelerated by hot compression in (austenite and ferrite) two phase region. Dual phase microstructures composed of martensite and ferrite with ferrite grain sizes of 1~2 μm were obtained, which exhibited superior mechanical properties.

26

Grajcar, Adam, Andrzej Kilarski, and Aleksandra Kozlowska. "Microstructure–Property Relationships in Thermomechanically Processed Medium-Mn Steels with High Al Content." Metals 8, no. 11 (November 9, 2018): 929. http://dx.doi.org/10.3390/met8110929.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

Анотація:

Detailed studies on microstructure–property relationships of thermomechanically processed medium-Mn steels with various manganese contents were carried out. Microscopic techniques of different resolution (LM, SEM, TEM) and X-Ray diffraction methods were applied. Static tensile tests were performed to characterize mechanical properties of the investigated steels and to determine the tendency of retained austenite to strain-induced martensitic transformation. Obtained results allowed to characterize the microstructural aspects of strain-induced martensitic transformation and its effect on the mechanical properties. It was found that the mechanical stability of retained austenite depends significantly on the manganese content. An increase in manganese content from 3.3% to 4.7% has a significant impact on the microstructure, stability of γ phase and mechanical properties of the investigated steels. The initial amount of retained austenite was higher for the 3Mn-1.5Al steel in comparison to 5Mn-1.5%Al steel—17% and 11%, respectively. The mechanical stability of retained austenite is significantly affected by the morphology of this phase.

27

Glover, Alexandra, Paul J. Gibbs, Cheng Liu, Donald W. Brown, Bjørn Clausen, John G. Speer, and Emmanuel De Moor. "Deformation Behavior of a Double Soaked Medium Manganese Steel with Varied Martensite Strength." Metals 9, no. 7 (July 7, 2019): 761. http://dx.doi.org/10.3390/met9070761.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

Анотація:

The effects of athermal martensite on yielding behavior and strain partitioning during deformation is explored using in situ neutron diffraction for a 0.14C–7.14Mn medium manganese steel. Utilizing a novel heat treatment, termed double soaking, samples with similar microstructural composition and varied athermal martensite strength and microstructural characteristics, which composed the bulk of the matrix phase, were characterized. It was found that the addition of either as-quenched or tempered athermal martensite led to an improvement in mechanical properties as compared to a ferrite plus austenite medium manganese steel, although the yielding and work hardening behavior were highly dependent upon the martensite characteristics. Specifically, athermal martensite was found to promote continuous yielding and improve the work hardening rate during deformation. The results of this study are particularly relevant when considering the effect of post-processing thermal heat treatments, such as tempering or elevated temperature service environments, on the mechanical properties of medium manganese steels containing athermal martensite.

28

Bhowmik, Kanti Ranjan Nath. "Aqueous Medium Synthesis and Characterization of Mixed-Ligand Molecular Complexes of Manganese(III)." Oriental Journal Of Chemistry 40, no. 1 (February 25, 2024): 202–8. http://dx.doi.org/10.13005/ojc/400125.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

Анотація:

A fluoride-aided stabilization of manganese(III) was demonstrated by the preparation of unique complexes of the molecular mixed ligand fluoromanganate(III) from an aqueous medium. Complexes of mixed ligand fluoromanganate(III) were synthesized by reacting MnO(OH), 40% HF with nitrogen donor ligands that may function as neutral ligands, such as pyridine, ethylene diamine, or imidazole. The molecular complexes that were generated are stable and may be kept in polythene bags for extended periods of time without losing their properties. Consistency may be determined in a number of ways, including chemical analysis of the manganese oxidation state and periodic estimation of manganese and fluoride levels. The compounds dissolve slowly in water and partly in polar organic solvents. Element analyses, chemical oxidation state determination, FT-IR, electronic spectra, magnetic moment measurements at room temperature, thermogravimetric analysis (TGA/DTA), scanning electron microscopy (SEM), and cyclic voltammetry studies were used to characterize the complexes. The complexes produced probably have a distorted octahedral shape.

29

Miljkovic, Miona, Sladjana Davidovic, Aleksandra Djukic-Vukovic, Mila Ilic, Milica Simovic, Mirjana Rajilic-Stojanovic, and Suzana Dimitrijevic-Brankovic. "Utilization of agro-industrial by-products as substrates for dextransucrase production by Leuconostoc mesenteroides T3: Process optimization using response surface methodology." Chemical Industry 75, no. 3 (2021): 135–46. http://dx.doi.org/10.2298/hemind200710015m.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

Анотація:

Dextransucrase (DS) is a glucosyltransferase (E. C. 2.4.1.5) that catalyzes the transfer of glucosyl residues from sucrose to dextran polymer and liberates fructose. This enzyme isassociated with a wide application range of dextran and oligosaccharides. DS production by Leuconostoc mesenteroidesT3 was optimized using a Central Composite Design under the Response Surface Methodology. Three variables were chosen for optimization: distillery stillage, sucrose and manganese concentration. The results showed that sucrose and manganese concentrations had a positive linear effect on DS production while all variable interactions (stillage-manganese, stillage-sucrose, and sucrose-manganese) had significant influences on the DS production. The maximal DS yield of 3.391?0.131 U cm-3, was obtained in the medium with 64.33 % distillery stillage concentration, 5.30% sucrose concentration and 0.022 % manganese concentration. Our study revealed the potential of distillery stillage combined with sugar beet molasses, supplemented with sucrose and manganese to be employed as a valuable medium growth for lactic acid bacteria and production of DS. Also, taking into consideration the origin of the substrates, utilization of industrial by-products in this way has a great environmental relevance and is in accordance with circular economy.

30

Allam, Tarek, Wolfgang Bleck, Christian Klinkenberg, Björn Kintscher, Ulrich Krupp, and Jenny Rudnizki. "The continuous casting behavior of medium manganese steels." Journal of Materials Research and Technology 15 (November 2021): 292–305. http://dx.doi.org/10.1016/j.jmrt.2021.08.019.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

31

Kumar singh, Manish, Anil Kumar Verma, and Ashok Kumar. "Microstructure and Mechanical properties of Medium Manganese Steels." Materials Today: Proceedings 56 (2022): 356–67. http://dx.doi.org/10.1016/j.matpr.2022.01.195.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

32

Zhenming, Xu. "Eutectic growth in as-cast medium manganese steel." Materials Science and Engineering: A 335, no. 1-2 (September 2002): 109–15. http://dx.doi.org/10.1016/s0921-5093(01)01946-3.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

33

Suh, Dong Woo, Joo Hyun Ryu, Min Sung Joo, Hong Seok Yang, Kyooyoung Lee, and H. K. D. H. Bhadeshia. "Medium-Alloy Manganese-Rich Transformation-Induced Plasticity Steels." Metallurgical and Materials Transactions A 44, no. 1 (September 15, 2012): 286–93. http://dx.doi.org/10.1007/s11661-012-1402-3.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

34

Wang, Cunyu, Xiaodong Li, Shuo Han, Lei Zhang, Ying Chang, Wenquan Cao, and Han Dong. "Warm Stamping Technology of the Medium Manganese Steel." steel research international 89, no. 9 (December 4, 2017): 1700360. http://dx.doi.org/10.1002/srin.201700360.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

35

Sun, Binhan, Fateh Fazeli, Colin Scott, Baoqi Guo, Clodualdo Aranas, Xin Chu, Mohammad Jahazi, and Stephen Yue. "Microstructural characteristics and tensile behavior of medium manganese steels with different manganese additions." Materials Science and Engineering: A 729 (June 2018): 496–507. http://dx.doi.org/10.1016/j.msea.2018.04.115.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

36

Poling, Whitney A., Emmanuel De Moor, John G. Speer, and Kip O. Findley. "Temperature Effects on Tensile Deformation Behavior of a Medium Manganese TRIP Steel and a Quenched and Partitioned Steel." Metals 11, no. 2 (February 23, 2021): 375. http://dx.doi.org/10.3390/met11020375.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

Анотація:

Third-generation advanced high-strength steels (AHSS) containing metastable retained austenite are being developed for the structural components of vehicles to reduce vehicle weight and improve crash performance. The goal of this work was to compare the effect of temperature on austenite stability and tensile mechanical properties of two steels, a quenched and partitioned (Q&P) steel with a martensite and retained austenite microstructure, and a medium manganese transformation-induced plasticity (TRIP) steel with a ferrite and retained austenite microstructure. Quasi-static tensile tests were performed at temperatures between −10 and 85 °C for the Q&P steel (0.28C-2.56Mn-1.56Si in wt.%), and between −10 and 115 °C for the medium manganese TRIP steel (0.14C-7.14Mn-0.23Si in wt.%). X-ray diffraction measurements as a function of strain were performed from interrupted tensile tests at all test temperatures. For the medium manganese TRIP steel, austenite stability increased significantly, serrated flow behavior changed, and tensile strength and elongation changed significantly with increasing temperature. For the Q&P steel, flow stress was mostly insensitive to temperature, uniform elongation decreased with increasing temperature, and austenite stability increased with increasing temperature. The Olson–Cohen model for the austenite-to-martensite transformation as a function of strain showed good agreement for the medium manganese TRIP steel data and fit most of the Q&P steel data above 1% strain.

37

Deniz, Fatih, and Elif Tezel Ersanli. "An Effectual Biosorbent Substance for Removal of Manganese Ions from Aquatic Environment: A Promising Environmental Remediation Study with Activated Coastal Waste of Zostera marina Plant." BioMed Research International 2020 (July 8, 2020): 1–8. http://dx.doi.org/10.1155/2020/7806154.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

Анотація:

In the present research paper, a biosorptive remediation practice for an aqueous medium sample polluted with manganese ions was implemented using the activated coastal waste of the Zostera marina plant. This is the first report in the literature on the utilization of current modified biological waste as a biosorbent substance for the removal of manganese ions from the water environment. The analyses of biosorbent characterization, environmental condition, kinetic, equilibrium, and comparison were performed to introduce the ability of prepared biosorbent for the removal of manganese from the aquatic medium. The biosorbent matter has a rough surface with numerous cavities and cracks and various functional groups for the biosorption of manganese. The environmental conditions significantly affected the manganese purification process, and the optimum working conditions were determined to be biosorbent quantity of 10 mg, pH of 6, manganese concentration of 30 mg L-1, and time of 60 min. The pseudo-second-order model best explained the kinetic data of biosorption operation. The biosorption equilibrium data were best described by the Freundlich isotherm. According to the Langmuir equilibrium model, the maximum purification potency was estimated to be 120.6 mg g-1. The comparison work revealed that the activated coastal waste of the Z. marina plant could be utilized as an effectual and promising biosorbent substance for the remediation of an aquatic environment contaminated with manganese ions.

38

Janulczyk, Robert, Susanna Ricci, and Lars Björck. "MtsABC Is Important for Manganese and Iron Transport, Oxidative Stress Resistance, and Virulence of Streptococcus pyogenes." Infection and Immunity 71, no. 5 (May 2003): 2656–64. http://dx.doi.org/10.1128/iai.71.5.2656-2664.2003.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

Анотація:

ABSTRACT MtsABC is a Streptococcus pyogenes ABC transporter which was previously shown to be involved in iron and zinc accumulation. In this study, we showed that an mtsABC mutant has impaired growth, particularly in a metal-depleted medium and an aerobic environment. In metal-depleted medium, growth was restored by the addition of 10 μM MnCl2, whereas other metals had modest or no effect. A characterization of metal radioisotope accumulation showed that manganese competes with iron accumulation in a dose-dependent manner. Conversely, iron competes with manganese accumulation but to a lesser extent. The mutant showed a pronounced reduction (>90%) of 54Mn accumulation, showing that MtsABC is also involved in Mn transport. Using paraquat and hydrogen peroxide to induce oxidative stress, we show that the mutant has an increased susceptibility to reactive oxygen species. Moreover, activity of the manganese-cofactored superoxide dismutase in the mutant is reduced, probably as a consequence of reduced intracellular availability of manganese. The enzyme functionality was restored by manganese supplementation during growth. The mutant was also attenuated in virulence, as shown in animal experiments. These results emphasize the role of MtsABC and trace metals, especially manganese, for S. pyogenes growth, susceptibility to oxidative stress, and virulence.

39

El-Shafei, Shaimaa, Fatma Ramadan, Mohamed Essawy, Ahmed Henaish, and Bassem Nabawy. "Geology, mineralogy and geochemistry of manganese ore deposits of the Um Bogma Formation, south-western Sinai, Egypt: genesis implications." Mining of Mineral Deposits 16, no. 3 (September 30, 2022): 86–95. http://dx.doi.org/10.33271/mining16.03.086.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

Анотація:

Purpose.This paper aims to understand the genesis and nature of the manganese ore deposits associated with the Ras Samra Member of the Um Bogma Formation in the southwest of Sinai. Methods. Mineralogical and geochemical studies of 50 selected samples of manganese ores and host shale have been conducted. These samples have been taken from different sites representing the Ras Samra Member. Findings. The dominant manganese minerals are pyrolusite and hausmannite. In most samples, helvite and hematite are noted in association with pyrolusite. In the investigated manganese ores, wide ranges of MnO (17.70-81.90 wt. %) and Fe2O3 (1.16-65.49 wt. %) concentrations are observed. Based on their Mn/Fe ratio, they can be classified into high-Mn ore content (76.94-6.46%), medium-Mn ore content (4.87-2.58%), and low-Mn ore content (1.51-0.30%). Originality. The compositions of major and trace elements in Ras Samra manganese ores, together with their textures and mineralogical compositions, suggest an epigenetic hydrothermal contribution for high-Mn ores, as well as syngenetic sedimentary precipitation for medium- Mn and low-Mn ores. The epigenetic nature of the high-Mn samples may be related to a younger phase of hydrothermal activity associated with Tertiary basalt flows. Ore-bearing hypogene solutions, which penetrate the bedding planes, have impregnated and cemented non-diagenetic terrigenous sandstones and shale. Practical implications. In contrast to low-Mn ores, high-Mn and medium-Mn ores of Um Bogma are preferable for obtai-ning a significant economic effect in the production of ferromanganese alloys. However, low-Mn ores need to be processed appropriately to achieve the desired quality in order to meet the present level of manganese demand in Egypt.

40

Kozłowska, Aleksandra, Barbara Grzegorczyk, Mateusz Morawiec, and Adam Grajcar. "Explanation of the PLC Effect in Advanced High-Strength Medium-Mn Steels. A Review." Materials 12, no. 24 (December 12, 2019): 4175. http://dx.doi.org/10.3390/ma12244175.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

Анотація:

The paper reviews the recent works concerning the Portevin–Le Chatelier (PLC) effect in Advanced High-Strength Steels (AHSSs) with a special attention to high-strength medium-manganese steels. Theories explaining the mechanism of the plastic instability phenomenon in steels with medium- and high-Mn contents were discussed. The relationships between microstructural effects such as TRIP (Transformation-Induced Plasticity), TWIP (Twinning-Induced Plasticity) and the PLC effect were characterized. The effects of processing conditions including a deformation state (hot-rolled and cold-rolled) and strain parameters (deformation temperature, strain rate) were addressed. Factors affecting the value of critical strain for the activation of serrated flow behavior in particular in medium-manganese steels were described.

41

Dong, Han, Wen Quan Cao, and Jie Shi. "Formation of an Ultrafine-Grained Austenite-Containing Microstructure from a Cold-Rolled Medium-Manganese Steel Processed Using Intercritical Annealing." Materials Science Forum 762 (July 2013): 31–37. http://dx.doi.org/10.4028/www.scientific.net/msf.762.31.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

Анотація:

The behavior of 60% cold-rolled medium-manganese steel (0.1C5Mn) during intercritical annealing, has been examined using various techniques. Microstructural observations showed a slight coarsening of the subgrain/grain structure during intercritical annealing, without any apparent change in the misorientation distribution. In addition, the formation of ultrafine austenite grains took place mainly at high-angle boundaries and rarely at low angle boundaries, suggesting a heterogeneous austenite nucleation process in this steel. The results indicated that the annealing behavior of cold rolled medium manganese steels is controlled by the extensive recovery of the ferrite phase and formation of austenite phase with an austenite volume fraction of ~20%. It was proposed that the segregation of manganese and carbon to high-angle boundaries promoted austenite nucleation and growth, as such segregation decreases the Gibbs energy of austenite.

42

Блинов, Андрей Владимирович, Давид Гурамиевич Маглакелидзе, Александр Александрович Кравцов, Анастасия Александровна Блинова, Алексей Алексеевич Гвозденко, Алексей Борисович Голик, Владислав Викторович Раффа, and Екатерина Васильевна Коновалова. "INFLUENCE OF ACTIVE ACIDITY OF THE MEDIUM ON THE STABILITY OF MNO NANOPARTICLES." Physical and Chemical Aspects of the Study of Clusters, Nanostructures and Nanomaterials, no. 12() (December 15, 2020): 33–41. http://dx.doi.org/10.26456/pcascnn/2020.12.033.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

Анотація:

В работе впервые представлены результаты исследования микроструктуры наночастиц диоксида марганца, стабилизированных серосодержащими аминокислотами. По результатам сканирующей электронной микроскопии обнаружено наличие в образцах наночастиц диаметром 15 - 30 нм. С помощью спектрофотомерии установлены оптимальные массовые соотношения прекурсоров для получения стабильных золей наночастиц диоксида марганца, которые составляют KMnO: метионин - 1:1 и KMnO: цистеин - 3:1. Исследование влияния активной кислотности среды на стабильность наночастиц диоксида марганца показало, что образцы MnO, полученные с использованием метионина, стабильны при 4 ≤ pH ≤ 11, а с использованием цистеина стабильны при 5 ≤ pH ≤ 8. In this work, for the first time the results of studying the microstructure of manganese dioxide nanoparticles stabilized with sulfur-containing amino acids are presented. According to the results of scanning electron microscopy, nanoparticles with a diameter of 15 - 30 nm were presented in the samples. The optimal mass ratios of precursors were established by means of spectrophotometry, to obtain stable sols of manganese dioxide nanoparticles. The optimal mass ratios were: KMnO : methionine - 1:1 and KMnO : cysteine - 3:1. Investigation of the effect of the medium active acidity on the stability of manganese dioxide nanoparticles showed that MnO samples obtained with methionine are stable at 4 ≤ pH ≤ 11, and with cysteine - at 5 ≤ pH ≤ 8 .

43

Mola, Javad, Guoqing Luan, Qiuliang Huang, Christian Schimpf, and David Rafaja. "Cementite evolution in medium manganese twinning-induced plasticity steels." Materialia 2 (October 2018): 138–47. http://dx.doi.org/10.1016/j.mtla.2018.07.013.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

44

Zhang, Lei, Cun-yu Wang, Heng-chang Lu, Wen-quan Cao, Chang Wang, Han Dong, and Leng Chen. "Austenite transformation and work hardening of medium manganese steel." Journal of Iron and Steel Research International 25, no. 12 (October 19, 2018): 1265–69. http://dx.doi.org/10.1007/s42243-018-0176-2.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

45

Farkas, Bence, Marek Kolenčík, Miroslav Hain, Edmund Dobročka, Gabriela Kratošová, Marek Bujdoš, Huan Feng, et al. "Aspergillus niger Decreases Bioavailability of Arsenic(V) via Biotransformation of Manganese Oxide into Biogenic Oxalate Minerals." Journal of Fungi 6, no. 4 (November 9, 2020): 270. http://dx.doi.org/10.3390/jof6040270.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

Анотація:

The aim of this work was to evaluate the transformation of manganese oxide (hausmannite) by microscopic filamentous fungus Aspergillus niger and the effects of the transformation on mobility and bioavailability of arsenic. Our results showed that the A. niger strain CBS 140837 greatly affected the stability of hausmannite and induced its transformation into biogenic crystals of manganese oxalates—falottaite and lindbergite. The transformation was enabled by fungal acidolysis of hausmannite and subsequent release of manganese ions into the culture medium. While almost 45% of manganese was bioextracted, the arsenic content in manganese precipitates increased throughout the 25-day static cultivation of fungus. This significantly decreased the bioavailability of arsenic for the fungus. These results highlight the unique A. niger strain’s ability to act as an active geochemical factor via its ability to acidify its environment and to induce formation of biogenic minerals. This affects not only the manganese speciation, but also bioaccumulation of potentially toxic metals and metalloids associated with manganese oxides, including arsenic.

46

Pleshakova, Ekaterina V., Milena A. Kasatkina, Clement T. Ngun, and Mikhail V. Reshetnikov. "A study of manganese-oxidizing microorganisms isolated from microbiocenoses of highly magnetic soils." Izvestiya of Saratov University. Chemistry. Biology. Ecology 22, no. 4 (December 15, 2022): 409–18. http://dx.doi.org/10.18500/1816-9775-2022-22-4-409-418.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

Анотація:

From the stand point of the possible use of microorganisms in water purification biotechnologies, studying microorganisms capable of removing dangerous pollutants such as heavy metals from the aquatic environment is of great importance. Microbial screening was conducted on isolates from microbiocenoses of highly magnetic soils of the city Mednogorsk (Orenburg region, Russia), to assess their resistance to manganese (II) ions. The objects of this research were nine strains of manganese-oxidizing microorganisms and two strains of iron-oxidizing microorganisms: Bacillus megaterium 69.3 and B. megaterium 69.5. It was observed that, most of the studied microorganisms were characterized by increased resistance to manganese (II) ions when grown on an agar medium. Maximum resistance to Mn (II) was observed in microbial strains: 55.2 and B. megaterium 69.5. The maximum tolerant concentration (MTC) of Mn (II) for these microorganisms was 300 and 350 mmol/L; the minimum inhibitory concentration (MIC) was 350 and 450 mmol/L, respectively. When studying the growth of the two microbial strains: 55.2 and B. megaterium 69.5 in liquid media for 5 days. It was discovered that, when cultured in a selective medium, microbial resistance of the strains to Mn (II) was higher compared to when cultured in a nutrient LB medium. The results showed high resistance of microorganisms to a range of Mn (II) concentrations: from 0,5 to 250 mmol/L in a liquid medium. Maximum growth of the studied microbial strains was observed at Mn (II) concentration of 10 mmol/L. These microbial strains with high resistance to Mn (II) open up the prospect of their practical use for biotechnological purposes involving the purification of drinking and wastewater from high manganese content.

47

Liu, Chunquan, Qichun Peng, Zhengliang Xue, Mingming Deng, Shijie Wang, and Chengwei Yang. "Microstructure-Tensile Properties Relationship and Austenite Stability of a Nb-Mo Micro-Alloyed Medium-Mn TRIP Steel." Metals 8, no. 8 (August 6, 2018): 615. http://dx.doi.org/10.3390/met8080615.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

Анотація:

This study investigated the microstructure–tensile properties relationship and the retained austenite room temperature stability of a Nb and Mo micro-alloyed medium manganese transformation induced plasticity (TRIP) steel. A number of findings were obtained. Most importantly, the steel after being processed by quenching and tempering (Q & T) exhibited excellent tensile properties, i.e., the strength of 878–1373 MPa, the ductility of 18–40% Mo, and Nb microalloying served to control the fraction of retained austenite and to improve tensile strength by fine grain strengthening. Excellent tensile properties were attributable to the large amount of retained austenite which produced a discontinuous TRIP effect. This effect led to the production a large amount of martensite which relieved the stress concentration, contributing to the coordinated deformation between the phases and thus improving the deformability of the steel. Additionally, the differences in Mn and C contents led to varying degrees of austenite stability and the length of the Lüders band decreased as the inter critical annealing temperature increased. The micro-alloyed medium manganese steel experimented on our study showed considerable improvement in tensile properties in comparison with the 5Mn-0.1C medium manganese steel in previous studies.

48

Liu, Caiyi, Yan Peng, Ling Kong, and Yanqiang Wang. "Effect of the Deformation Degree on the Microstructure Evolution of an Austenite Reverted Transformation-Annealed Medium Manganese Steel." Metals 10, no. 7 (July 4, 2020): 887. http://dx.doi.org/10.3390/met10070887.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

Анотація:

An Fe-0.15C-1.2Si-5Mn-0.09Nb-0.08V-0.07Mo (wt.%) medium manganese steel that was subjected to a novel austenite reverted transformation (ART) annealing process. This paper is based on the conventional ART annealing process, and a deformation and ART annealing process is proposed. The influence of the deformation degree on the microstructure and grain size of the medium manganese steel was determined by scanning electron microscopy (SEM), transmission electron microscopy (TEM), electron backscatter diffraction (EBSD) and X-ray diffraction (XRD). The results show that the deformation had a great effect on the microstructure evolution and grain size. The microstructure of the medium manganese steel after the deformation and ART annealing process was consistent with the theory of austenite reverse transformation, i.e., the martensite reverse transformation into austenite occurred during the deformation and ART annealing process. The final microstructure was a mixture of martensite and austenite. As the deformation degree increases, the martensite gradually refines, and carbides precipitate in the lath martensite. The retained austenite is gradually transformed from very large to small and is distributed between the martensite laths. The results show that when deformation occurs in the austenite region, a small deformation can obtain more retained austenite.

49

Gaipov, T. E., A. B. Makhanbetov, B. E. Myrzabekov, A. Tazhibayev, S. Bitursyn, N. Shertayeva, M. Duisembiyev, and E. K. Abdulina. "EXTRACTION OF MANGANESE FROM MANGANESE ORES BY ELECTROCHEMICAL LEACHING." RASAYAN Journal of Chemistry 15, no. 03 (2022): 1806–11. http://dx.doi.org/10.31788/rjc.2022.1536898.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

Анотація:

The basis of the traditional technology of hydrometallurgical processing of manganese ore is the process of ore roasting. The results obtained in this article make it possible to exclude the roasting process and directly leach the crushed ore under the action of an electric current. The process of electrochemical leaching includes two simultaneous operations: reduction of hard-soluble higher manganese oxides (pyrolusite - MnO2, vernadite - MnO2- nH2O) in an acid medium and transition of reduced manganese into an aqueous solution. The main part of the reduction process of higher manganese oxides proceeds in the Fe2+ ↔ Fe3+ catalytic system, the remaining part proceeds at the cathode under stirring. The degree of influence of iron (III) ions was determined. During studies on the transfer of manganese into solution from manganese ore by electrochemical leaching, the influence of L:S: ratio, sulfuric acid concentration, and cathodic current density on the degree of manganese extraction were studied. As a result of electrochemical leaching studies in the presence of the catalyst system, Fe2+ ↔ Fe3+ under optimal electrolysis parameters the degree of manganese extraction was 99%.

50

O, Velichko, Kamkina L, Yunshen Du, Mianovska Ya, and Velichko K. "Smelting of metallic manganese and manganese alloys in the gas-oxygen refining converter." Theory and practice of metallurgy, no. 6 (May 4, 2021): 19–28. http://dx.doi.org/10.34185/tpm.4.2021.03.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

Анотація:

The purpose of the work is the substantiation and development of technological solutions for smelting metallic manganese and its alloys based on the duplex technology "arc electric steel-smelting furnace-converter of gas-oxygen refining." Methods: thermodynamic analysis by stage reactions and phase transformations of starting substances involved in chemical reactions; laboratory and industrial research; chemical analysis. Scientific innovation: when converting low-phosphorous manganese slag and involving recycled silicomanganese, the possibility of obtaining metallic manganese is shown when pulverized lime is introduced during blowing. The possibility of smelting low-carbon ferromanganese and metallic manganese in the converter of gas-oxygen refining by the silicothermal method is substantiated. Practical value: In semi-industrial and industrial gas-oxygen refining converters, technologies for obtaining low- and medium-carbon ferromanganese and metallic manganese by the silicothermal method and blowing high-carbon ferromanganese with gaseous oxygen have been tested. The silicothermal method provided high productivity, ease of metallurgical redistribution, high manganese extraction, minimal manganese "hits" with evaporation and transition of manganese to slag.

Статті в журналах з теми "Medium manganèse"

Оформте джерело за APA, MLA, Chicago, Harvard та іншими стилями