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Published By Lviv Polytechnic National University

1996-4196, 1996-4196

2021 ◽  
Vol 15 (4) ◽  
pp. 551-558
Author(s):  
Sarra Sabrina Aiche ◽  
◽  
Hodhaifa Derdar ◽  
Zakaria Cherifi ◽  
Mohammed Belbachir ◽  
...  

In the present work we have explored a new catalyst prepared with Algerian clay and a new method to synthesise polystyrene and poly(1,3-dioxolane). This technique consists of using Algerian modified clay (Kaolinite-H+) as a green catalyst. Kaolinite-H+ is a proton exchanged clay which is prepared through a simple exchange process. Synthesis experiments are performed in bulk. The polymerization of styrene in bulk leads to the yield of 83 % at room temperature with the reaction time of 3 h. Molecular weight of the obtained polystyrene is calculated by 1H NMR and is about 2196 g/mol. Polymerization of (1,3-dioxolane) is carried out at room temperature with the reaction time of 3 h and polymerization yield of 91 %. The calculated molecular weight of the obtained poly(1,3-dioxolane) is about 573 g/mol. The structure of the obtained polymers is confirmed by FT-IR and 1H NMR. The modified clay (Kaolinite-H+) is characterized by FT-IR, XRD and SEM analysis.


2021 ◽  
Vol 15 (4) ◽  
pp. 591-598
Author(s):  
Elizabeth Refugio-García ◽  
◽  
Gerardo Vázquez-Huerta ◽  
José Miranda-Hernández ◽  
Jessica Osorio-Ramos ◽  
...  

Alumina-based composites reinforced with titanium were manufactured by powder techniques. Characterizations indicate that titanium content affects densification which in turn causes positive effects on hardness and toughness. Microstructure presents grains of irregular shape and small sizes. Electrochemical impedance spectroscopy indicates that additions of titanium on Al2O3 enhance its corrosion resistance.


2021 ◽  
Vol 15 (4) ◽  
pp. 500-511
Author(s):  
Khatuna Barbakadze ◽  
◽  
Witold Brostow ◽  
Nathalie Hnatchuk ◽  
Giorgi Lekishvili ◽  
...  

We have developed novel antibiocorrosive multifunctional hybrid materials based on functionalizedperfluoroalkylmethacrylate copolymerswith epoxy groups in main chainsand selected biologically active compounds.The hybrids are transparent, showgood adhesion to various surfaces (plastic, wood),high viscoelastic recovery in scratch testing,low wear rates and glass transitions above 323 K. No phase separation is seen in scanning electron micrography. Enhanced mechanical strength and good abrasion resistance are advantages for uses of our protective and antibiocorrosive coatings in various applications including protection of cultural heritage.


2021 ◽  
Vol 15 (4) ◽  
pp. 599-607
Author(s):  
Vitalii Orlovskyi ◽  
◽  
Myroslav Malovanyy ◽  
Volodymyr Biletskyi ◽  
Mykola Sokur ◽  
...  

A new competitive class of plugging compositions (weighted non-shrink plugging materials) has been created using as components a fly ash from thermal power station, a weighting additive and a superplasticizer. X-ray phase analysis identified the composition of new materials formed in the hydration process of the developed plugging compositions. The kinetic curves of the plugging material expansion in a wide temperature range have been obtained. Rational temperature regimes of plugging materials hardening according to the criteria of strength and gas permeability of cement stone have been determined.


2021 ◽  
Vol 15 (4) ◽  
pp. 621-626
Author(s):  
Metehan Oğulcan Lap ◽  
◽  
Yasin Kanbur ◽  
Ümit Tayfun ◽  
◽  
...  

Mussel shell is one of the most hazardous aquaculture wastes and its powder was used as an additive for bio-degradable poly (lactic acid) in this current study. Bio-composites were fabricated via conventional melt mixing technique followed by an injection moulding process. The effects of mussel shell powder inclusion on mechanical, melt-flow, water uptake and morphological performance of poly (lactic acid)-based green composites were reported.


2021 ◽  
Vol 15 (4) ◽  
pp. 559-566
Author(s):  
Vahab Ghalandari ◽  
◽  
Hamidreza Bagheri ◽  
Ali Mohebbi ◽  
Hadi Esmaeili ◽  
...  

In this study, the effect of chemical composition of the raw material on the clinker burnability was studied by determination of free CaO (wt %) content of clinker. The burnability of two types of Portland clinker was investigated for silica modules of 2.3, 2.5 and 2.7 and lime saturation factor of 0.88–0.98. In addition, using the Multi-gene genetic programming (MGGP) model, the burnability of clinker was predicted. The results of MGGP model indicated that the performance of the model for predicting the amount of free CaO (wt %) was acceptable. Moreover, using MGGP, a promising correlation was introduced for accurately calculating the amount of free CaO (wt %). The performance of this correlation was compared with FL-Smidth, and it was established that the average errors of MGGP correlation and FL-Smidth equation were 2.95 and 7.45 %, respectively.


2021 ◽  
Vol 15 (4) ◽  
pp. 457-464
Author(s):  
Prabu Deivasigamani ◽  
◽  
Senthil Kumar Ponnusamy ◽  
Sathish Sundararaman ◽  
Suresh A ◽  
...  

The efficiency of surface modified nanoscale zerovalent iron (nZVI) composite by cashew nut shell (CNS) was tested for the removal of cadmium ions from the aqueous solutions. 2 g/l CNS-nZVI was efficient for 98% removal. The adsorption capacity was 35.58 mg/g. The Freundlich isotherm (R2 = 0.9769) and the pseudo-second order adsorption kinetics data fitted well. This proved CNS-nZVI has a high removal efficiency for Cd(II) from aqueous solutions.


2021 ◽  
Vol 15 (4) ◽  
pp. 526-535
Author(s):  
Oleksiy Pylypenko ◽  
◽  
Olga Smirnova ◽  
Olga Skorynina-Pohrebna ◽  
Oleksandr Khoroshev ◽  
...  

The investigation data of the formation peculiarities of oxide films on the Ti6A14V alloy in tartaric acid solutions have been given. It is shown that the behavior of alloy forming dependences is conditioned by the anode current density. At ja < 0.5 A∙dm-2 the continuous oxide film is not formed on the alloy surface and the preset value of the final voltage on the cell is not reached. With an increase in ja > 0.5 A∙dm-2, alloy forming dependences show a linear behavior that is indicative of the formation of low porous films. In these conditions, the oxide film formation rate is in direct proportion to the value of ja. The electrochemical oxidation of Ti6A14V alloy in tartaric acid solutions results in the formation of interference-colored oxide films. The oxide film ultimate thickness and color are defined by the preset voltage and are independent of the current density and electrolyte concentration. The isolating properties of obtained films were studied by the way of the cathode polarization of oxidized specimens in the sulfate copper-plating electrolyte. The research done allows us to make a conclusion that electrochemical copper deposition is a convenient tool for the detection of defective spots in oxide films. It is shown that due to the specific features of the reduction kinetics of Cu2+ ions on the oxidized titanium it is reasonable to use for the studies the initial sections of polarization dependences that correspond to ΔE = 0.2–0.25 V. The alloy polarization dependences allow us to establish unavailability of apparent dependences between the oxidation current density, the electrolyte concentration, the cell final voltage value and the polarization that occurs during the Cu2+ ion reduction. The anodic connection of copper-coated specimens conditions the reversible dissolution of a greater portion of the specks of copper deposits. It is indicative of the electron conduction of film defects. The obtained data allow us to vary the electrolysis parameters in a wide range with no significant influence of the treatment mode of Ti6A14V alloy on the quality of oxide coatings.


2021 ◽  
Vol 15 (4) ◽  
pp. 536-542
Author(s):  
Volodymyr Dutka ◽  
◽  
Olena Aksimentyeva ◽  
Yaroslav Kovalskyi ◽  
Natalya Oshchapovska ◽  
...  

Monomolecular films of diacyl diperoxides at the water–air phase interface have been studied. Their behaviour is influenced by the structure of the molecule and the solvent. The numerical values of the areas of molecules that are extrapolated to zero pressure are different, which indicates a different conformation of the molecules in the monolayer. The conformational states of diperoxides were calculated by quantum chemical methods. Experimental data and quantum chemical calculations are consistent with each other.


2021 ◽  
Vol 15 (4) ◽  
pp. 567-574
Author(s):  
Huda A. Jaber ◽  
◽  
Marwa F. Abdul Jabbar ◽  

The current study deals with the removal of cationic dye (brilliant green) and anionic dye (methyl orange) from wastewater by using sunflower husk as an adsorbent. The operation takes place batch wise by applying several concentrations of the dye solution with various adsorbent amounts, at a range of initial PH values and particle sizes at varying contact time intervals. The percent of dye removed for two dyes increased with increasing time and adsorbent dose and decreased with increasing the dye concentration and particle size. The equilibrium time differed according to conditions used. The optimum removal for brilliant green dye was 98 %, which was achieved at 50 ppm dye concentration, 2 g\l adsorbent dose, 75 µm particles size and pH 7 at contact time of 1 h, compared with low removal for methyl orange that reached 54 % under optimum conditions (dye concentration 10 ppm, adsorbent dose 4 g/l, pH 3 at the same particles size and time). Kinetic studies were conducted and revealed that the adsorption was well defined by pseudo-second order model and could be described by the Langmuir isotherm.


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