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Abstrakt

The influence of external factors, temperature and flow velocity on the corrosion processes St3 in model solutions petrochemical plant recycled water with high salinity and hardness without open systems and in the presence of the inhibiting composition. It was found that an increase in temperature leads to a linear increase in corrosion rates, and the change in circulating water flow rate leads to the extreme nature of corrosion processes; optimal conditions are determined. Recommended use of cathodic inhibitors or mixed type inhibitor, in particular, the composition "SVOD-BI" (means for controlling the biological corrosion), which can significantly reduce the effect of temperature and flow on the corrosion rate St3, promotes the growth and strengthening of the oxide film in the presence of oxygen, increases the degree of protection of steel and preventing the formation of at its surface carbonate-calcium deposits.
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Autorzy i Afiliacje

G. Tatarchenko
N. Biloshitska
O. Vodolazskyy

Abstrakt

Carbonic anhydrase is an important enzyme that can play a significant role in the processes of lowering carbon dioxide concentration in the atmosphere. The aim of the work was to investigate the extracellular carbonic anhydrase (CA) production by the bacteria Pseudomonas fragi. In the research, we focused on the evaluation of the phase of bacterial growth correlated with carbonic anhydrase production and on the evaluation of induction of CA production by calcium carbonate concentration in the nutrient medium. Presented data indicated that calcium carbonate can serve as the only carbon source for Pseudomonas fragi, inducing carbonic anhydrase secretion to culture broth. The enzyme was produced mainly in the adaptation growth phase reaching the maximal activity at the end of this phase or at the beginning of the growth phase. The maximal enzyme activity detected in all batches was at a similar level. The enzyme activity was constant but lower in the exponential phase growth. Therefore, the enzyme production is not growth-dependent, but it is correlated with bacteria adaptation to cultivation conditions.
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Autorzy i Afiliacje

Andrzej Tietz
1
Małgorzata M. Jaworska
1
ORCID: ORCID

  1. Warsaw University of Technology, Faulty of Chemical and Process Engineering, ul. Warynskiego 1, 00-645 Warsaw, Poland

Abstrakt

The general objective of this research has been to identify the factors and conditions of migration of CaCO3 within glaciers and their marginal zones in Svalbard . Special attention has been paid to the cryochemical processes responsible for precipitation of calcium carbonate in icing (naled ice) formed near fronts of polythermal glaciers during winter. Estimates of the importance of those processes in respect of the general mineral mass transfer in the glacier system are attempted here. Field studies concerning the carbonate contents in proglacial sediments and icing fields were carried out in the Werenskioldbreen and the Elisebreen basins (S and NW Spitsbergen respectively). A functional model of CaCO3 migration in a glacier system is proposed which indicates the various paths of the mineral mass flow. Considerations on intensity of glacial processes permitted quantitative estimation of the particular components in respect to the Werenskioldbreen basin. Cryochemical processes do not appear to be of overriding importance in such migration but, clearly, they play a specific role in retaining CaCO3 in the proglacial zone on land. The crystalline forms present in the icings, which have many lattice defects, are very easily re-dissolved or removed by wind.

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Autorzy i Afiliacje

Elżbieta Bukowska-Jania

Abstrakt

To fabricate a lead-free solder with better properties, a surface-modified precipitate calcium carbonate (PCC) was added as a reinforcement phase to tin-zinc (Sn-9Zn) solder. The surface modification of PCC was done by using electroless plating to deposit nickel (Ni) layer on the PCC. Based on microstructure analysis, a thin layer of Ni was detected on the reinforcement particle, indicating the Ni-coated PCC was successfully formed. Next, composite solder of Sn-9Zn-xNi-coated PCC (x = 0, 0.25, 0.50, 1.00 wt.%) was prepared. The morphology and phase changes of the composite solder were evaluated by using optical microscope and X-ray diffraction (XRD). Significant refinement on the grain size of Zn was seen with the additions of Ni-coated PCC, with a new phase of Ni3Sn4 was detected along with the phases of Sn and Zn. The wettability of Sn-9Zn was also improved with the presence of Ni-coated PCC, where the wetting angle decreased from 28.3° to 19.4-23.2°. Brinell hardness test revealed up to 27.9% increase in hardness for the composite solder than the pristine Sn-9Zn solder. This phenomenon contributed by the increased in dislocation resistance through Zener pinning effect and Zn grain refinement within the composite solder which enhanced the overall properties of the composite solder.
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Autorzy i Afiliacje

L.W. Keong
1
F.F. Zainal
1
ORCID: ORCID
M.Z. Kasmuin
1
A.A. Mohamad
2
M.F.M. Nazari
1
ORCID: ORCID
M. Nabiałek
3
ORCID: ORCID
B. Jeż
4
ORCID: ORCID

  1. Universiti Malaysia Perlis (UniMAP), Center of Excellence Geopolymer & Green Technology (CEGeoGTech) 02600, Arau, Perlis, Malaysia
  2. Universiti Sains Malaysia, School of Materials and Mineral Resources Engineering, Advanced Soldering Materials Group, 14300 Nibong Tebal, Penang, Malaysia
  3. Częstochowa University of Technology, Faculty of Production Engineering and Materials Technology, Department of Physics, 19 Armii Krajowej Av., 42-200 Częstochowa, Poland
  4. Czestochowa University of Technology, Faculty of Mechanical Engineering and Computer Science, Department of Technology and Automation, l9c Armii Krajowej Av., 42-200 Czestochowa, Poland

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