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Number of results: 4
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Abstract

Nanostructured systems based on ZnO nanoparticles composite systems/polymer fibers have attracted a lot of attention in the last years because of their applications in multiple areas. Nanofibres based on polymers are used in many domains such as nanocatalysis, controlled release of medicines, environmental protection and so on. This work show the synthesis of cellulose acetate butyrate (CAB) nanofiber useful as substrates for growing ZnO nanocrystals and that ZnO is an unorganic metal oxide nanoparticle used to improve the piezoelectric properties of the polymer. The piezoelectric propertiesof ZnO-doped polymeric was investigated with atomic force microscopy and measurements were performed, in contact technique, in piezoelectric response mode (PFM).In order to analyze the structural and textural features, the obtained materials were characterized using advanced physical-chemical techniques such as X-ray diffraction (XRD), Atomic Force Microscopy (AFM), Scanning Electron Microscopy (SEM). The XRD patterns show the characteristic reflections of ZnO with a hexagonal type wurtzit structure and the broad peaks of the polymer. The SEM images reveal the presence of ZnO nanoparticles on top of the polymer nanofibres.In most ZnO-based nanocomposites their morphology is uncontrolled (agglomerated granules), but in ase of using cellulose acetobutyrate this becomes controlled by observing through flower-like structures SEM and AFM) The study of the functional properties of ZnO/polymer fiber composite systems showed that they have piezoelectric properties which give them the characteristics of smart material with possible sensor and actuator applications.Recent literature reports that the synthesis and characterization of ZnO-polymer nanocomposites are more flexible materials for various applications.
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Authors and Affiliations

G. Calin
1
ORCID: ORCID
L. Sachelarie
1
ORCID: ORCID
N. Olaru
2
ORCID: ORCID

  1. Apollonia University of Iasi, Faculty of Dental Medicine, 11 Pacurari Str., 700511, Iasi, Romania
  2. Institute of Macromolecular Chemistry “Petru Poni” Iasi, Aleea Grigore Ghica Voda,41A, 700487, Iasi, Romania
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Abstract

Introduction of polymers into the cement composites improves same of the properties of concretes and mortars. Therefore, the polymer-cement composites are successfully used in construction. The model of microstructure formation in cement composites modified with thermoplastic polymer (pre-mix modifiers) has already been developed and successfully implemented. However, the formation of microstructure in the case of epoxy-cement composites (containing post-mix modifier) demonstrates same peculiarities which should be taken into account when modelling the process. The microstructure of epoxy-cement composites and its formation is discussed in the paper. The model is offered, formulated on the basis of the microscopic observations and results of testing.

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Authors and Affiliations

P. Łukowski
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Abstract

The article presents modelling using artificial neural networks (ANN) of the phenomenon of creep of comply polymer SIKA PS which can be used in various applications in civil engineering. Data for modelling was gathered in compressive experiments conveyed under a set of fixed conditions of compressive stress and temperature. Part of the datawas pre-processed by smoothing and rediscretisation and served as inputs and targets for network training and part of the data was left raw as control set for verification of prognosing capability. Assumed neural network architectures were one- and two-layer feedforward networks with Bayesian regularisation as a learning method. Altogether 55 networks with 8 to 12 neurons in varying structural configurations were trained. Fitting and prognosing verification was performed using mean absolute relative error as a measure; also, results were plotted and assessed visually. In result, the research allowed for formulation of a new rheological model for comply polymer SIKA PS in time, stress and temperature field domain with fitting quality of mean absolute relative error 1.3% and prognosis quality of mean absolute relative error 8.73%. The model was formulated with the use of a two-layer network with 5+5 neurons.
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Authors and Affiliations

Anna M. Stręk
1
ORCID: ORCID

  1. Cracow University of Technology, Faculty of Civil Engineering, ul. Warszawska 24, 31-155 Kraków, Poland
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Abstract

In this study some of the experimental results of water shut-off treatments in oil and gas production wells were presented. The effect of water saturation of Miocene rocks of the Carpathian Foredeep on the relative permeability to gas was analyzed. Also, wide review of the worldwide publications from the point of view of the results obtained in water shut-off treatments in oil and gas formation was presented. Based on experimental results efficiency of relative permeability modification of sandstone from Szydłowiec to brine and nitrogen by four selected chemicals polymers and microgels was evaluated. Experimental results indicated that trend changes of permeability modification strongly depends on the fluid used in the RPM treatment. Moreover, efficiency of permeability modification to brine depends on flow rate of brine through the core - the lower brine flow rate the higher efficiency of the RPM treatment. RPM product number 1 caused significant loss of permeability to brine ca. 60% and slight permeability modification to gas ca. 18%. This permeability change to brine and gas was obtained by modification of formation wettability what affects well productivity. In the case of product number 2 which is based on microgels technology, also significant modification of selective permeability to brine was observed. Loss of permeability to brine was in the range of 65 to 90% while to gas ca. 50%.

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Authors and Affiliations

Sławomir Falkowicz
Stanisław Dubiel
Renata Cicha-Szot

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