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Košice, Slovakia

Trpcevska J.,Technical University of Kosice | Hokova B.,Technical University of Kosice | Briancin J.,Institute of Geotechnics | Koralova K.,Technical University of Kosice | Piroskova J.,Technical University of Kosice
International Journal of Mineral Processing

Zinc ash generated during the hot dip galvanizing process is an important source of secondary zinc. The result of zinc ash processing technologies is the formation of zinc in the metallic form or in the form of zinc compounds. The present paper is aimed at possibilities of metallic zinc recovery from the coarse-grained fraction of zinc ash (d N 1.25 mm) from hot dip galvanizing by the pyrometallurgical process on designed laboratory equipment. Designed equipment for laboratory experiments used centrifugal force and protective atmosphere of a nitrogen flow during the process of melting and separation of zinc. The aim of the pyrometallurgical processing study on the designed equipment was to investigate the effect of time (30, 60, 90 min) and temperature (480, 500, 550, 600, 650, 700 °C) on recovery of smelted zinc. The most favourable conditions in terms of recovery of smelted zinc (88%) were obtained at the temperature of 500 °C and the melting time of 30 min. The influence of the melting time on zinc recovery was obvious only at the temperature of 480 °C, where extension of time led to an increase of zinc recovery. © 2015 Elsevier B.V. All rights reserved. Source

Martin S.,Institute of Montaneous science and Environmental Protection | Maria P.,Institute of Geotechnics
Acta Montanistica Slovaca

The utilization of fly ashes in Slovakia is lower than in other countries and dumping of fly ashes prevails. The dumping changes chemical and phase composition of fly ashes and so it decreases possibilities for their utilization. Fly ashes are mainly used in building industry, where the content of loss on ignition (LOI) is limited due to standards. Black coal fly ashes produced in Slovakia have a high content of loss on ignition - more than 20% - so they straight utilization in building industry is not possible. The current possibility for their utilization is in geopolymer synthesis. Products with 28-day compression strength of 35.7 MPa and 180-day compression strength of 55.0 MPa were obtained by alkali activation of fly ashes with 23.25% LOI with 8 wt% Na 2O and their next hardening in temperature of 80 °C during 6 hours. Products have a great frost-resistance and aggressive environments resistance (NaCl a H 2SO 4 solutions). Source

Chobal O.,Uzhhorod National University | Chobal O.,Institute of Materials Science | Rizak I.,National Aerospace University - Kharkiv Aviation Institute | Ilkovic S.,University of Presov | And 6 more authors.
Solid State Sciences

The Sn2P2S6 ferroelectric nanocrystalline powders have been prepared by high-energy milling and their size distribution has been determined. The temperature dependences of heat capacity and the temperatures of phase transitions of ferroelectric nanopowders are obtained. The modified model of B. Jiang and L. Bursill [Phys. Rev. B 60, 9978 (1999)] for the ferroelectric nanoparticles with phase transitions close to the tricritical Lifshitz point is proposed and used to explain the experimental results. Observed smearing of the heat capacity anomaly is explained by the particle size effect and the influence of defects. The influence of the milling time on the investigated properties of Sn2P2S6 ferroelectric powders was studied. © 2013 Elsevier Masson SAS. All rights reserved. Source

Cernan J.,Technical University of Kosice | Rodzinak D.,Technical University of Kosice | Briancin J.,Institute of Geotechnics
Powder Metallurgy

Investigation was focused on resistance of Astaloy CrL type sintered material to contact fatigue. The material in two versions (0?3 and 0?7 wt-%C) was covered with TiCN coating. The results show that resistance to contact fatigue increased substantially, up to the value of about 3410±90 MPa. This increase was influenced primarily by the properties of coating. In this case, the impact of the matrix was of secondary importance. The results obtained in the evaluation of life in terms of contact fatigue were confronted with those of the microscopic observation of generation and propagation of cracks leading to the formation of pitting, as well as with other tests. It describes the impact of contact fatigue stress to changes in the material at the point of application. A special section is devoted to the use of finite element method (FEM) for simulation of the Hertzian stress and changes during contact strain. © 2014 Institute of Materials, Minerals and Mining. Source

Jung M.Y.,Korea Research Institute of Bioscience and Biotechnology | Kim J.-S.,Korea Research Institute of Bioscience and Biotechnology | Paek W.K.,National Science Museum | Styrak I.,Institute of Animal Physiology | And 8 more authors.
International Journal of Systematic and Evolutionary Microbiology

A Gram-positive, rod-shaped, endospore-forming bacterium, designated strain BLB-1T, was isolated from samples of tidal flat sediment from the Yellow Sea. 16S rRNA gene sequence analysis demonstrated that the isolate belonged to the Bacillus rRNA group 2 and was closely related to Bacillus massiliensis CIP 108446T (97.4 %), Bacillus odysseyi ATCC PTA-4993T (96.7 %), Lysinibacillus fusiformis DSM 2898T (96.2 %) and Lysinibacillus boronitolerans DSM 17140T (95.9 %). Sequence similarities with related species in other genera, including Caryophanon, Sporosarcina and Solibacillus, were,<96.1 %. Chemotaxonomic data supported the affiliation of strain BLB-1T with the genus Lysinibacillus. The major menaquinone was MK-7, the cell-wall sugars were glucose and xylose, the cell-wall peptidoglycan type was A4α (L-Lys-D-Asp), the major polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine and several unknown phospholipids, and the major fatty acids were anteiso-C15: 0 (35.6 %), iso-C15: 0 (25.6 %) and anteiso-C17: 0 (16.5 %). The most closely related species, Bacillus massiliensis and Bacillus odysseyi, were also assigned to this genus based on phylogenetic analysis and phenotypic data. The results of DNA-DNA hybridizations and phenotypic tests supported the differentiation of all three taxa from species of the genus Lysinibacillus with validly published names. Thus, strain BLB-1T (=KCTC 13296T=JCM 15800T) represents a novel species, for which the name Lysinibacillus sinduriensis sp. nov. is proposed. It is also proposed that Bacillus massiliensis CIP 108446T (=4400831T=CCUG49529T=KCTC 13178T) and Bacillus odysseyi NBRC 100172T (534hs-1T = ATCC PTA-4993T =NRRL B-30641T =DSM 18869T =CIP 108263T =KCTC 3961T) be transferred to the genus Lysinibacillus as Lysinibacillus massiliensis comb. nov. and Lysinibacillus odysseyi comb. nov., respectively.© G 2012 IUMS. Source

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