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Number of results: 9
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Abstract

Effects of confinement on mechanical, structural and thermodynamic properties of uniform fluids are very well understood. In contrast, a general theory based on statistical thermodynamics for confined nonuniform and non-isotropic phases, such as the lamellar phase, is in its infancy. In this review we focus on the lamellar phase confined in a slit or in a pipe in order to illustrate various effects of confinement. We limit ourselves to the results obtained by M. Tasinkevych, V. Babin and the author for lamellar phases in oil-water-surfactant mixtures within a generic semi-microscopic model, using a mean-field approximation. We show that compared to isotropic fluids the excess grand potential contains additional terms associated with structural deformations. These terms depend on the type of the confining walls, the shape of the container and on the thickness of the lamella. As a result of the dependence of the structure of the confined lamellar phase on the shape of the container, capillary lamellarization and capillary delamellarization is found in slits and in pipes respectively.

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Authors and Affiliations

A. Ciach
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Abstract

When designing injectable scaffolds for biomedical applications, it is crucial to determine the conditions for the formation of unlimited structures, in particular the kinetics at constant temperature. Despite many studies, these conditions have not been characterized so far after injection, which is such an important application aspect. The aim of the research is to discuss the impact of the injection application on the polymer structure and to propose new criteria for assessing the potential of thermosensitive biopolymer sols, considering the flow under high shear rates during the administration.
Based on the analysis of the obtained results of rheological tests, it was shown that the flow through the needles causes a significant change in the elastic properties that define the polymer structure, with almost unchanged viscous properties. As a consequence, the parameters characterizing the polymer coil change, which, combined with the quantitatively proven fragmentation, indicates that injection application may affect the size of the coils that will not reach the critical size of the aggregating nucleus.
Finally, extended research procedures for the conscious design of injectable scaffolds are proposed as well as key rheological parameters to ensure thermoinduced aggregation preceded by shear during injection are provided.
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Authors and Affiliations

Anna Rył
1
ORCID: ORCID
Piotr Owczarz
1
ORCID: ORCID

  1. Department of Chemical Engineering, Lodz University of Technology, Wolczanska 213, 93-005 Lodz
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Abstract

This paper introduces a novel approach to building network cluster structures, based on the modified LEACH algorithm. The proposed solution takes into account the multitasking of the network infrastructure, resulting from various functions performed by individual nodes. Therefore, instead of a single head, dedicated to a given cluster, a set of heads is selected, the number of which corresponds to the number of performed functions. Outcomes of simulations, comparing the classical and the multifunctional approach, are presented. The obtained results confirm that both algorithms deliver similar levels of energy consumption, as well as efficiency in terms of the number of individual nodes discharged.
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Authors and Affiliations

A. Paszkiewicz
1
ORCID: ORCID
C. Ćwikła
2
M. Bolanowski
1
ORCID: ORCID
M. Ganzha
3
ORCID: ORCID
M. Paprzycki
3
ORCID: ORCID
M. Hodoň
4
ORCID: ORCID

  1. Department of Complex Systems, Rzeszow University of Technology, Al. Powstańców Warszawy 12, Rzeszów 35-959, Poland
  2. Rzeszow University of Technology, Al. Powstańców Warszawy 12, Rzeszów 35-959, Poland
  3. Systems Research Institute Polish Academy of Sciences, Newelska 6, Warszawa 01-447, Poland
  4. Department of Technical Cybernetics, University of Žilina, Univerzitná 8215/1, 010 26 Žilina, Slovakia
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Abstract

The high-pressure torsion (HPT) of Ti-Fe alloys with different iron content has been studied at 7 GPa, 5 anvil rotations and rotation speed of 1 rpm. The alloys have been annealed before HPT in such a way that they contained different amounts of α/α' and β phases. In turn, the β phase contained different concentration of iron. The 5 anvil rotations correspond to the HPT steady-state and to the dynamic equilibrium between formation and annihilation of microstructure defects. HPT leads to the transformation of initial α/α' and β-phases into mixture of α and high-pressure ω-phase. The α → ω and β → ω phase transformations are martensitic, and certain orientation relationships exist between α and ω as well as β and ω phases. However, the composition of ω-phase is the same in all samples after HPT and does not depend on the composition of β-phase (which is different in different initial samples). Therefore, the martensitic (diffusionless) transformations are combined with a certain HPT-driven mass-transfer. We observed also that the structure and properties of phases (namely, α-Ti and ω-Ti) in the Ti – 2.2 wt. % Fe and Ti – 4 wt. % Fe alloys after HPT are equifinal and do not depend on the structure and properties of initial α'-Ti and β-Ti before HPT.

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Authors and Affiliations

B. Straumal
A. Kilmametov
A. Gornakova
A. Mazilkin
B. Baretzky
A. Korneva
P. Zięba
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Abstract

Polycrystalline samples BaTiO3 and the solid solutions Ba0.9Sr0.1TiO3, Ba0.9Sr0.1Ti0.9Sn0.1O3, Ba0.9Sr0.1Ti0.8Sn0.2O3 were obtained by means of a mechanochemical treatment based on the high-energy ball milling technique and next a high temperature solid state reaction method. The influence of synthesis condition on microstructural, dielectric and ferroelectric properties of obtained solid solutions were investigated. The structure and morphology of the investigated samples were characterized by an X-ray diffraction (XRD) and scanning electron microscopy (SEM). The characterization of electrical properties of the ceramics within the temperature range from –130°C to 250°C were performed by means of a dielectric spectroscopy method at the frequency ranging from 0.1 Hz to 10 MHz. The diffusion of the paraelectric – ferroelectric phase transition and dielectric relaxation for ceramic samples are described.

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Authors and Affiliations

W. Bąk
P. Dulian
B. Garbarz-Glos
D. Czekaj
A. Lisińska-Czekaj
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Abstract

This paper presents the results of obtaining and investigations of Pb1–xBax(Zr1–yTiy)1–zSnzO3 (PBZTS) ceramics with constant x = 0.03 and y = 0.02, and variable z = 0, 0.04, 0.06 and 0.08 (abbreviations of the samples were following PBZTS0, PBZTS4, PBZTS6, PBZTS8, respectively). The investigated compositions are close to rhombohedral-orthorhombic morphotropic phase boundary. The ceramic samples have been obtained by conventional ceramic technology from simple oxides PbO, ZrO2, TiO2, SnO2 and barium carbonate BaCO3. The ceramic powders, after calcination, have been pressed into discs and sintered using free sintering (FS) method. For samples obtained in such a way, the dielectric properties at various frequencies and electrical conductivity have been investigated. The increase of Sn content orders the microstructure of ceramics, and as a result the improvement of the dielectric properties of ceramic samples can be obtained.

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Authors and Affiliations

D. Brzezińska
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Abstract

This paper discusses the influence of the direction of applied deformation on the ability to gelation of thermosensitive chitosan hydrogels. The application of the shear rate equal in value to the classically performed oscillatory measurements leads to significantly different shapes of experimental curves. It was found that the type of mechanically applied deformation has a significant impact on the gelation ability of colloidal chitosan solutions and conditions of sol-gel phase transition. Simple shear leads to a phase transition at a lower temperature or in a shorter time compared to oscillatory tests. Moreover, based on the final values of dynamic viscosity in rotational measurements, it was found that stronger crosslinking of the polymer structure was observed.

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Authors and Affiliations

Anna Rył
ORCID: ORCID
Piotr Owczarz
ORCID: ORCID
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Abstract

This paper conducts low temperature welding tests on Q460GJC thick plate (60 mm), and based on the basic theory of phase transformation structure evolution, a three-dimensional microstructure evolution analysis method for large welded joints is established, and the analysis of the evolution process of multi-layer and multi-pass weld structure under the low temperature environment of thick plates is completed. The comparison and analysis of test and numerical simulation results are in good agreement, which proves that the welding phase transformation model realizes the digitalization of metallurgical phase transformation in steel structure welding, and optimizes welding process parameters. It is of great significance to improve the quality of welding products and lay a foundation for predicting the performance of welded joints from the micro level.
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Authors and Affiliations

Xin Li
1
ORCID: ORCID
Meng Wang
1
Han Qi
2
Jie Li
3
Changchun Pan
4
Jing Zhang
3
Jingman Lai
3

  1. Beijing Construction Engineering Group Co., LTD, Beijing, 100032, P.R. China
  2. Beijing Third Construction Engineering Co., LTD, Beijing, 100032, P.R. China
  3. Central Research Institute of Building and Construction Co., Ltd. MCC, Beijing, 100032, P.R. China
  4. China State Shipbuilding International Engineering Co., Ltd. CSIE, Beijing, 100000, P.R. China
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Abstract

TiNi alloys have excellent shape memory properties and corrosion resistance as well as high biocompatibility. This study investigated the effects of copper addition on the phase transitions and electrochemical corrosion behaviors of Ti50Ni50-xCux alloys. TiNi, Ti50Ni47Cu3, Ti50Ni44Cu6, and Ti50Ni41Cu9 alloys were prepared using vacuum arc remelting followed by 4 h homogenization at 950°C. Differential scanning calorimetry and X-ray diffraction analyses were conducted. The corrosion behaviors of the alloys were evaluated using potentiodynamic polarization test in Hank’s balanced salt solution at a temperature of 36.5 ± 1°C. The TiNi alloy showed phase transitions from the cubic B2 phase to the monoclinic B19’ phase when the alloy was thermally cycled. The addition of copper to the TiNi alloy played a major role in stabilizing the orthorhombic B19 phases during the phase transitions of Ti50Ni50-xCux alloys. The shifts in the corrosion potential toward the positive zone and the low corrosion current density were affected by the amount of Cu added. The corrosion resistance of the TiNi alloy increased with increasing copper content.

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Authors and Affiliations

Kwangmin Lee
ORCID: ORCID
Sanghyun Rho

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