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1

Epoxy-Based Composites Reinforced with MMT and TiO2 Nanoparticles and Supported with the Honeycomb Aramid Core: A Case Study

Stawarz Sylwester

Tribologia

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2024

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nr 3

119--132

EN

This work presents the results of investigations into the thermal, dynamic mechanical, and tribological properties of epoxy resin reinforced with titanium dioxide nanoparticles and organically modified montmorillonite in varying proportions. Additionally, reinforcement of an aramid honeycomb core was used to compare the properties of samples with and without the honeycomb structure. A modified T-07 tester was employed to assess the wear resistance of materials and metal coatings during rubbing with loose abrasive. Thermodynamic tests were performed using the three-point bending mode on an Instrument DMA SDTA861 thermal analyzer in the temperature range from 20°C to 140°C. It was found that at an operating temperature of around 57°C, the lowest stiffness was observed in the sample without an aramid core and with 2 vol.% particulate filler in the composite. Tribological tests determined the wear resistance, with composites containing montmorillonite exhibiting the highest wear rates, while the sample with the highest proportion of TiO2 nanoparticles was the most wear-resistant. Notably, the wear rate decreased further when the friction area was along the walls of the aramid honeycomb core.

PL

Praca przedstawia wyniki badań właściwości termicznych, dynamiczno-mechanicznych i tribologicznych żywicy epoksydowej wzmacnianej nanocząstkami tlenku tytanu i organicznie modyfikowaną montmorylonitą w różnych proporcjach. Dodatkowo zastosowano wzmocnienie rdzenia z plastra miodu z aramidu, aby porównać właściwości próbek z rdzeniem i bez niego. Do oceny odporności na zużycie materiałów i powłok metalowych użyto zmodyfikowanego testera T-07. Badania termodynamiczne przeprowadzono w trybie zginania trójpunktowego przy użyciu analizatora DMA SDTA861 w zakresie temperatur od 20°C do 140°C. Stwierdzono, że przy temperaturze roboczej około 57°C najmniejszą sztywność wykazywała próbka bez rdzenia aramidowego i z 2% obj. wypełniacza cząsteczkowego. W badaniach tribologicznych oceniono odporność na zużycie, przy czym kompozyty z montmorylonitem wykazały najwyższe wskaźniki zużycia, a próbka z największym udziałem nanocząsteczek TiO2 była najbardziej odporna na zużycie. Warto zauważyć, że współczynnik zużycia zmniejszał się, gdy obszar tarcia znajdował się wzdłuż ścianek rdzenia aramidowego plastra miodu.

2

Solar-Driven Degradation of Ciprofloxacin in the Aquatic Environment

Sowik Paulina, Kowalska Katarzyna, Felis Ewa

Journal of Ecological Engineering

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2024

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Vol. 25, nr 3

195--204

EN

Ciprofloxacin (CIP), a pharmaceutical compound, -occurs as a micropollutant in various types of environmental matrices including wastewater, because it is resistant to removal via conventional methods - due to its persistent characteristics. For this reason, in this work the efficiency of photodegradation CIP (2 mg L-1) in Milli-Q water (MW) and tap water (TP) was investigated using TiO2 and ZnO at a concentration of 20 mg L-1 each. The tests were performed without and in the presence of SO42-ions (250 mg L-1) as one of main components of the aquatic, environmental matrices. Solar-driven photocatalysis using TiO2-P25 and ZnO improved the removal efficiency of CIP compared to its solar photolysis. In all cases approximately 90% removal of CIP was observed after 20 to 30 minutes, but no mineralization processes was achieved. The most efficient degradation was obtained using TiO2 at concentration of 20 mg L-1 in DW without the presence of SO42- after 5 minutes. The photodegradation rate constants estimated kt=0.644 min-1 and kQUV=0.249 L kJ-1. The complexity of the matrix affected the efficiency of CIP removal, favouring DW. The impact of sulfate anions also depended on the matrix: in distilled water, their impact was negative on the photocatalysis process efficiency, while in tap water, they slightly accelerated a process of CIP decomposition. Taking this into account, photocatalysis is an efficient; however, further research is necessary.

3

Investigating the Effects of PU-Based Back-Coating with Boric Acid and Titanium Dioxide Additives on Flame Retardancy Levels and Comfort Properties of 100% Cotton Denim Fabric

Öztürkmen Ebru, Güneşoğlu Cem, Topalbekiroğlu Mehmet

Fibres & Textiles in Eastern Europe

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2024

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Vol. 32, no. 4

13--21

EN

This study aimed to develop a cost-effective and resource-efficient application to enhance the thermal stability, flame retardancy, self-cleaning, and antibacterial properties of cotton denim fabrics through a single-step, flexible, and simple polyurethane (PU) based back-coating method, ultimately increasing the use of denim fabrics in daily and work clothes thanks to the increased functionality. This method utilizes boric acid (H3BO3) and a binary composite of H3BO3-titanium dioxide (TiO2) as functional additives while considering comfort parameters. Limiting oxygen index (LOI) and vertical burning tests were conducted to explore the thermal stability and flame retardancy of the samples, while assessments of air permeability, water vapour permeability, thermal resistance, and thermal absorptivity were performed to investigate the comfort properties. Comparing two kinds of back-coated denim fabrics, H3BO3-TiO2 back-coated cotton fabric showed the best flame retardancy with the lowest char length (45 mm) and highest LOI (27%). The air permeability values of back-coated fabrics decreased by approximately half compared to the untreated denim fabric. Although the water vapour permeability values decreased, they were less affected by the coating. Coating application reduced thermal conductivity and thermal absorbency, resulting in more thermally resistant denim fabric. This study demonstrates the potential utility of a PU-based coating incorporating TiO2 and H3BO3 on traditional cotton denim fabrics to enhance flame resistance while minimizing any adverse effects on the overall thermal comfort of the fabric.

4

Performance of Graphene Oxide–Titanium Dioxide, Polyethersulphone Membranes for Industrial Wastewater Treatment

Jassim Zahraa Salah, Braihi Auda Jabbar, Shabeeb Kadhum M.

Ecological Engineering & Environmental Technology

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2024

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Vol. 25, iss. 9

336--347

EN

The use of hydrophilic polymer membranes derived from nanocomposites for the treatment of industrial wastewaters has garnered significant attention lately. When producing membranes, the fouling problems of these membranes may be lessened by adding hydrophilic additives to the polymer solution. In order to create the membranes by the phase inversion approach, 0.8 weight percent of polyethersulfone (PES) solution was mixed with a combination (1:1) of graphene oxide:titanium dioxide nanoparticles (GO:TiO2 NPs) at various weight percentages (0.2, 0.4, 0.6, and 0). The absence of spectral peaks at 899 and 1669 cm-1 in the completed membranes, as determined by FTIR studies, suggests that the GO:TiO2 NPs component’s hydrolytic breakdown caused the membrane structure’s pores to develop. The membrane topology was rough with a wider range of heights and abnormalities at low NP concentrations, as the histogram of the 3D AFM pictures illustrates. On the other hand, the 2D photos showed that the surface smoothed out and had fewer peaks and valleys at high NP concentrations, which decreased the surface’s roughness. Surface scanning electron microscopy pictures demonstrated that when the membrane’s structure evolved from narrow to broad porosity with uneven expansion of porous patches, adding more nanoparticles increased the water flow. However, cross-sectional SEM pictures showed that the membrane’s constituent parts were a thick porous layer with micropores and elongated finger structures that resembled pores, and a thin skin layer. The membrane’s porosity increased with increasing NP concentration, as demonstrated by porosity calculations and contact angle measurements. This improved selectivity, made the membrane less prone to fouling, and made cleaning safer and easier, particularly for hydrophilic foulants like proteins and polysaccharides. The addition of NPs resulted in an estimated 83% and 92% increase in the flow of pure water and bovine serum albumin (BSA), respectively. However, the BSA rejection initially dropped before increasing once again.

5

Carbide Cutting Tool Coatings Characterization of 8YSZ

Kareem Shaimaa J., Wurood Asaad M., Abbas Sundus, Al-Ethari Haydar

Advances in Science and Technology. Research Journal

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2024

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Vol. 18, no. 4

410--419

EN

Using a duplex deposition of TiO2/8YSZ on a carbide cutting tool, a successful sol-gel procedure was achieved, resulting in high homogeneity, good dispersion, and a low average value of surface roughness (223.6)nm. Thermal experiments were done to see how well the coating layers could withstand heat transfer and thermal deterioration. Residual stresses for coated and uncoated carbide cutting tools are measured after thermal shock (thermal shock). Both were immediately chilled in ice water after being heated for 90 minutes for coated inserts and 30 minutes for uncoated inserts at 500, 600, 700, 800, 900, and 1200 °C. For inserts, thermal shock from 900 °C results in significantly different damage mechanisms. The uncoated outside surface is still delineated by a crack network and is surrounded by nearby homogenous cells, but the coated insert (sol gel TBC) in this case really has a few tiny cracks beginning at the edge. The coated insert (sol-gel TBC) fails after being heated to 1200 °C and then cooled in water to freezing which is caused the start of the duplex coating degradation.

6

Ammonia level sensor using tapered optical fiber coated with titanium dioxide-incorporated porphyrin

Parasuti Frazna, Hikmawati Dyah, Trilaksana Herri, Yasin Moh.

Optica Applicata

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2023

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Vol. 53, nr 3

353--361

EN

Since ammonia is water-soluble, environmental studies have shown that the industrial waste such as fertilizer manufacturing, food products, palm oil, urea fertilizer industry can cause very serious damage to water body ecosystems if not properly managed, resulting in a decrease in water quality. Devices based on optical technology, especially devices that combine optical fibers and nanomaterials, are identified as highly sensitive to the species of interest by detecting changes in physicochemical properties. A practical, easy-to-use, inexpensive instrument for detecting ammonia level was proposed using tapered optical fiber (TOF) coated with titanium dioxide-incorporated porphyrin. TOF was fabricated by simultaneously stretching and heating. The preparation of TiO2/porphyrin/gelatine was prepared to coat tapered optical fiber by dipping. SEM analysis shows an increase in length and a decrease in diameter, also the successful coating of titanium dioxide and porphyrin in the taper region. The EDX analysis also proves the presence of the Ti element in the TOF layer. The TOF produces significant sensing performances toward the ammonia liquid concentration level. The TOF coated with titanium dioxide-incorporated porphyrin can detect a one ppm difference in ammonia concentration with a certain range of output voltage for every concentration has.

7

A new magnetic-hybrid photoreactor for photocatalytic water disinfection

Paszkiewicz Oliwia, Wang Kunlei, Kordas Marian, Rakoczy Rafał, Kowalska Ewa, Markowska-Szczupak Agata

Chemical and Process Engineering : New Frontiers

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2023

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Vol. 44, nr 3

art. no. e22

EN

Environmental contamination is an urgent topic to be solved for sustainable society. Among various pollutants, microorganisms are believed to be the most dangerous and difficult to be completely inactivated. In this research, a new hybrid photoreactor assisted with rotating magnetic field (RMF) has been proposed for the efficient removal of two types of bacteria, i.e., gram-negative Escherichia coli and gram-positive Staphylococcus epidermidis. Three self-synthesized photocatalysts were used, based on commercial titanium(IV) oxide – P25, homogenized and then modified with copper by photodeposition, as follows: 0.5 Cu@HomoP25, 2.0 Cu@HomoP25 and 5.0 Cu@HomoP25 containg 0.5, 2.0 and 5.0 wt% of deposited copper, respectively. The response surface methodology (RSM) was employed to design the experiments and to deteremine the optimal conditions. The effects of various parameters such as copper concentration [% w/w], and treatment time [h] and frequency of RMF [Hz] were studied. Results: analysis of variance (ANOVA), revealed a good agreement between experimental data and proposed quadratic polynomial model (R2 = 0:86 for E. coli and R2 = 0:69 for S. epidermidis). Experimental results showed that with increasing copper concentration, time and decreasing of frequency of RMF, the removal efficiency was increased. Accordingly, the water disinfection efficiency of 100% in terms of the independent variables was optimized, including copper concentration c = 5% and 2.5% w/w, time t = 3 h and 1.3 h and frequency of rotating magnetic field f = 50 Hz and 26.6 for E.coli and S. epidermidis, respectively. This study showed that response surface methodology is a useful tool for optimizing the operating parameters for photocatalytic disinfection process.

8

Simultaneous photooxidation and photoreduction of phenol and Cr(VI) ions using titania modified with nanosilica

Kądziołka Daria, Grzechulska-Damszel Joanna, Schmidt Beata

Polish Journal of Chemical Technology

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2022

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Vol. 24, nr 4

23--29

EN

The photocatalytic process of phenol oxidation and Cr(VI) reduction in the presence of nano-silica modified titania was carried out. The activity of composites was tested using two different light sources. The photocatalysts with 10% of nanosilica showed the highest activity. The calcination temperature (200–800 °C) significantly determined the sensitivity of the obtained materials to the light source used. Photocatalysts alternately adsorbed and desorbed Cr(VI) ions from the reaction mixture during irradiation. In the one-component mixture, complete oxidation of phenol was observed using material calcined at 650 °C, after 3 h of UV-VIS irradiation. In the reaction mixture of Cr(VI) and phenol, the highest activity was demonstrated by photocatalyst calcined at 300 °C. The concentration of phenol decreased in proportion to the decrease of chromium ions. The obtained titania-silica composites showed oxidizing properties towards phenol and reductive properties toward Cr(VI) ions.

9

Structural and photocatalytic properties of Ni-TiO2 photocatalysts prepared by mechanochemical synthesis assisted with calcination

Kucio Karolina, Charmas Barbara, Zięzio Magdalena, Pasieczna-Patkowska Sylwia

Physicochemical Problems of Mineral Processing

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2022

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Vol. 58, iss. 4

art. no. 150348

EN

In the study the mechanochemical synthesis in the planetary ball mill was used to prepare photocatalytic materials obtained on the basis of TiO2 and nickel(II) acetylacetonate as a Ni2+ source. Three materials with different contents of Ni2+: 5, 10 and 20% wt. were prepared. The obtained materials were calcinated at 800°C for 1 h. Their physicochemical properties were investigated using the N2 adsorption/desorption, FT-IR/PAS, XRD, UV-Vis/DRS and SEM methods. Additionally, thermal stability of the obtained materials was examined (TGA/DTG/DTA). Photocatalytic activity of the samples was tested in relation to the aqueous solution of Safranin T (initial concentration C0 = 1×10-5 mol L-1) at the visible light (Vis). The results indicate that the mechanochemical synthesis is an effective and simple method for preparing materials with photocatalytic properties. All obtained materials were characterized by greater photocatalytic activity compared to the initial TiO2.

10

Biological synthesis and characterization of titanium dioxide nanoparticle from Cynodon dactylon

Renitta R. E., Jebaseeli T. J., Dhanaraj A., Paul S.

Journal of Achievements in Materials and Manufacturing Engineering

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2022

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Vol. 113, nr 1

31--41

EN

Purpose: There are several advantages of using a biological technique to produce nanoparticles versus a chemical method. The primary goal of this work is to characterize and biologically synthesize titanium dioxide (TiO2) nanoparticles from Cynodon dactylon. The characterization has experimented with UV-Vis Spectroscopy, EDX analysis, SEM, XRD, and FTIR. Design/methodology/approach: The suggested study uses a simple biological technique to accomplish the systematic biological synthesis of TiO2 nanoparticles utilizing Cynodon dactylon plant extract and titanium tetra isopropoxide as a precursor. UV-Vis spectroscopy, Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR), and X-Ray Diffraction (XRD) are used to confirm the fabrication of the TiO2 nanoparticles. The plant extract as well as titanium-based nanoparticles of the herb, Cynodon dactylon will be tested for its antibacterial activity against human pathogens. This eco-friendly technique for nanoparticle synthesis is straightforward and adaptable to major commercial manufacturing and technological applications. Findings: Cynodon dactylon biosynthesis of TiO2 nanoparticles is efficient, nutrition dependent, does not employ hazardous compounds, and happens at neutral pH levels. The antibacterial study results show that TiO2 nanoparticles synthesized using Cynodon dactylon have good antibacterial properties. TiO2 nanoparticle method of action against bacteria is unknown. This is an alternative process for synthesising TiO2 nanoparticles, apart from other chemical protocols, since this is quick and non-toxic. The antimicrobial property of biologically synthesized TiO2 nanoparticles against Escherichia coli, Staphylococcus aureus, and Acinetobacter baumannii was tested at four different doses of 15 μl/mg, 25 μl/mg, 50 μl/mg, and 75 μl/mg. The present results revealed the 75 μl/mg concentration got the highest zone of inhibition (15, 13, 15 mm) for Acinetobacter baumannii, Staphylococcus aureus, and Escherichia coli. Research limitations/implications: Many nanoparticles smaller than 100 nm are firmly agglomerated with each other in the study. TiO2 nanoparticles absorb in the UV region of 200 to 400 nm. XRD measurements confirmed the presence of TiO2 nanoparticles in the biologically produced sample. In our work, EDX was used to confirm the existence of Ti after its synthesis by Cynodon dactylon. Practical implications: The biosynthesized TiO2 nanoparticles utilizing Cynodon dactylon plant extracts exhibit a good potent antibacterial activity. The proposed results showed that the TiO2 nanoparticles are well suited for biomedical applications. Originality/value: The suggested research identifies several eco-friendly, biological, and cost-effective procedures for manufacturing nano-coated herbal products. The agar well diffusion technique was used to assess antibacterial activities toward test pathogens such as Acinetobacter baumannii, Staphylococcus aureus, and Escherichia coli.

11

Selected properties of polypropylene-TiO2 composites after exposure to UV rays – preliminary study

Olesik Piotr, Peryt Aleksander, Stępień Krzysztof, Frączek Violetta, Mackiewicz Krzysztof, Molka Weronika, Musiał Oliwia, Różańska Weronika, Jesionek Marcin

Composites Theory and Practice

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2022

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R. 22, nr 1

21--24

EN

In this study the mechanical properties of polypropylene (PP) with a small amount of TiO2, after UV-C exposure were preliminarily analyzed. The effectiveness of titanium oxide was evaluated in two alternative applications: TiO2 as the polymer filler and TiO2 as a protective outer coating. The samples were exposed to UV-C rays for 1000 hours. It was found that an addition of 5 wt.% TiO2 to PP matrix results in a 60% smaller decrease in Rg after 1000 h of exposure to UV-C than in the case of neat polypropylene. It was also found that the addition of TiO2 to the polypropylene matrix is more effective than TiO2 applied as a coating component. The Rg decrease after exposure is about 35% in this case. The research confirmed that TiO2 submicrometric particles seem to be a very good component in reducing the sustainability of polypropylene to UV radiation.

12

Titanium dioxide as a safe additive to sunscreen emulsions

Janczarek Marcin, Szaferski Waldemar

Chemical and Process Engineering

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2022

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Vol. 43, nr 4

483-–490

EN

Titanium dioxide with its ability to be a UV light blocker is commonly used as a physical sunscreen in the cosmetic industry. However, the safety issues of TiO2 application should be considered more in-depth, e.g., UV light-induced generation of reactive oxygen species which can cause DNA damage within skin cells. The proper modification of titanium dioxide to significantly limit its photocatalytic properties can contribute to the safety enhancement. The modification strategies including the process conditions and intrinsic properties of titanium dioxide were discussed. The selected examples of commercially available TiO2 materials as potential components of cosmetic emulsions dedicated for sunscreens were compared in this study. Only rutile samples modified with Al2O3 and/or SiO2 showed inhibition of photocatalytic activity.

13

Synthesis of magnesium aluminate spinel doped TiO2 from magnesite waste

Canikoğlu Nuray

Archives of Metallurgy and Materials

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2022

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Vol. 67, iss. 1

311--316

EN

Magnesium aluminate spinel (MgAl2O4) is an important refractory material of magnesia origin. It is formed by the reaction of magnesium and aluminum oxides. In this study, TiO2 was added to magnesite waste and alumina (Al2O3) powders in different proportions and the mixtures were sintered at different temperatures after shaping. The aim of this study was to produce spinel economically by recycling waste materials. Therefore, titanium dioxide (TiO2) added magnesium aluminate spinel was produced and the products obtained were characterized by XRD and SEM-EDS analyses. In addition, bulk density, apparent porosity and microhardness values were measured and the effects of TiO2 additive on magnesium aluminate properties were examined. The better values were determined in samples doped 4 wt.% TiO2 at the sintering temperature of 1400°C.

14

Corrosion Damage Mechanisms of TiO2 Cold-Sprayed Coatings

Lachowicz Marzena, Winnicki Marcin

Archives of Metallurgy and Materials

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2022

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Vol. 67, iss. 3

975--985

EN

Cold spraying as a low-temperature coating deposition method is intended for thermally sensitive materials. Due to its precise temperature control, it limits the formation of structural defects, and can therefore be easily applied to spray corrosion protective coatings made from metal or metal-ceramic powders. However, the formation of pure ceramic coatings with the use of cold spraying is still not so common. Titanium dioxide is one of the most interesting ceramics due to its photocatalytic properties. Nevertheless, these types of coating materials usually work in a corrosion favoring humid atmosphere. In the presented paper, amorphous TiO2 powder was deposited onto aluminum alloys and steel substrates and then submitted to potentiodynamic corrosion tests in a 3.5 wt.% NaCl solution. The as-sprayed coating showed phase transition from amorphous TiO2 to anatase, and also revealed porosity. As a result, electrolytes penetrated the coating and caused undercoating corrosion in the tested environment of an aqueous NaCl solution. The analysis of the potentiodynamic curves showed that the presence of the coating decreased corrosion potential on both substrates. It arose from the mixed phases of TiO2, which consisted of photocathode - amorphous material and photoanode - crystalline anatase. The phase mixture induced the galvanic corrosion of metallic substrates in the presence of electrolytes. Moreover, pitting-like corrosion and coating delamination were detected in aluminium alloy and steel samples, respectively. Finally, the corrosion mechanism of the titanium dioxide coatings was characterized and described.

15

Powłoki o właściwościach samoczyszczących aplikowane na materiały tekstylne

Masłowska-Lipowicz Iwona, Słubik Anna, Wyrębska Łucja

Technologia i Jakość Wyrobów

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2021

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R. 66

124--133

PL

Właściwości samoczyszczące powierzchni cieszą się dużym zainteresowaniem ze względu na szerokie możliwości ich zastosowań w różnych gałęziach przemysłu (tekstylia, budownictwo, urządzenia sanitarne, części samochodowe, panele fotowoltaiczne, urządzenia elektroniczne, lotnictwo, kosmonautyka i in.). Powierzchnie samoczyszczące mogą mieć właściwości hydrofobowe lub hydrofilowe. Samoczyszczące tekstylia umożliwiają oszczędzanie wody, środków piorących, energii i czasu. Ponadto, są odporne na przenikanie wody i kumulowanie zanieczyszczeń na ich powierzchni. Opracowano metodę modyfikacji tkaniny bawełnianej w celu nadania jej właściwości samoczyszczących. Metoda ta opiera się na aplikacji poli(dimetylosiloksanu) oraz nanometrycznego dwutlenku tytanu na tkaninę bawełnianą.

EN

Self-cleaning properties of surfaces are of great interest due to the wide range of their applications in various industries (textiles, construction, sanitary equipment, automotive parts, photovoltaic panels, electronic devices, aviation, aerospace, etc.). Self-cleaning surfaces can have hydrophobic or hydrophilic properties. Self-cleaning textiles allow saving water, detergents, energy and time. Moreover, they are resistant to water penetration and accumulation of contaminants on their surface A method of modifying cotton fabric in order to make it self-cleaning has been developed. This method is based on the application of poly(dimethylsiloxane) with terminal hydroxyl groups and nanometric titanium dioxide to cotton fabric.

16

Research on dielectric parameters of epoxy resin based nanocomposites using the impedance spectroscopy method

Dąda Anna, Błaut Paweł

Przegląd Elektrotechniczny

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2021

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R. 97, nr 12

234--237

EN

Due to the modern requirements regarding the reliability of electrical devices operation, research on improving the parameters of materials and insulation systems, in particular high-voltage ones, used in the production, transmission and distribution of electricity is still valid. One of the research directions is the development and application of insulating materials modified with nanofillers. The paper presents the results of stability studies of selected dielectric properties of samples of insulation materials based on epoxy resin modified with titanium dioxide TiO2 nanopowders. Changes in parameters caused by different wt% nanofiller content and their long-term stability after 10,000 hours from manufacturing are compared and analyzed.

PL

Współczesne wymagania dotyczące niezawodności pracy urządzeń elektrycznych powodują, że wciąż aktualnymi są badania dotyczące poprawy parametrów materiałów i układów izolacyjnych, w szczególności wysokonapięciowych, stosowanych w wytwarzaniu, przesyle i rozdziale energii elektrycznej. Jednym z kierunków badań jest opracowanie i zastosowanie materiałów izolacyjnych modyfikowanych nanowypełniaczami. Referat przedstawia wyniki badań stabilności wybranych właściwości dielektrycznych próbek materiałów izolacyjnych na bazie żywicy epoksydowej modyfikowanej nanoproszkami tlenku tytanu TiO2. Porównane są i analizowane zmiany parametrów powodowane różną zawartością wt% nanowypełniacza oraz ich stabilność długoczasowa po 10.000 godzin od wytworzenia.

17

The removal of Fe from the reduced ilmenite via aeration leaching assessing the effect of operating parameters

Ibrahim Siti Asmidar, Yunus Farhana, Ariffin Kamar Shah, Sheikh Abdul Hamid Sheikh Abdul Rezan, Ismail Suhaina, Jabit Nurul Ain

Physicochemical Problems of Mineral Processing

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2021

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Vol. 57, iss. 6

182--195

EN

An upgrade of Malaysian ilmenite (FeTiO3) concentrate to synthetic rutile (TiO2) using aeration leaching was investigated in this study. Carbothermal reduction using Sarawak MukahBalingan coal and compressed National Gas (CNG) as a reductant was used to produce reduced ilmenite (RI) as an intermediate phase consisting of titanium oxide matrix with metallic iron prior to aeration leaching. Metallic iron was dissolved in ammonium chloride solution after the reduction process, separating synthetic rutile in the leaching residue. This study aims to evaluate the leaching parameters, such as concentration, temperature, and leaching time. The optimum conditions established by the design of the experiment (DOE) and the analysis of variance (ANOVA) has indicated that leaching temperature was the most significant parameter for iron dissolution. It was found that iron dissolution at a maximum value of 97.0% was achieved at an optimum condition of 0.5 M NH4Cl at 90°C for 7 hours. With an initial weight of 46 wt.%TiO2 and 37 wt.% Fe2O3, ilmenite was successfully upgraded to 80 wt.% and 8 wt.%, respectively. In conclusion, Malaysian ilmenite has a high potential value to be upgraded to synthetic rutile by aeration leaching with ammonium chloride via Becher process.

18

Solar cells based on copper oxide and titanium dioxide prepared by reactive direct-current magnetron sputtering

Wisz Grzegorz, Sawicka-Chudy Paulina, Sibiński Maciej, Starowicz Zbigniew, Płoch Dariusz, Góral A., Bester Mariusz, Cholewa M., Woźny Janusz, Sosna-Głębska A.

Opto-Electronics Review

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2021

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Vol. 29, No. 3

97--104

EN

In this study, solar cells based on copper oxide and titanium dioxide were successfully manufactured using the reactive direct-current magnetron sputtering (DC-MS) technique with similar process parameters. TiO₂/CuO, TiO₂/Cu₂O/CuO/Cu₂O, and TiO₂/Cu₂O solar cells were manufactured via this process. Values of short-circuit current efficiencies, short-circuit current density, open-circuit voltage, and maximum power of PV devices were investigated in the range of 0.02÷0.9%, 75÷350 µA, 75÷350 µA/cm², 16÷550 mV, and 0.6÷27 µW, respectively. The authors compare solar cells reaching the best and the worst conversion efficiency results. Thus, only the two selected solar cells were fully characterized using I-V characteristics, scanning electron microscopy, X-ray diffraction, ellipsometry, Hall effect measurements, and quantum efficiency. The best conversion efficiency of a solar cell presented in this work is about three times higher in comparison with the authors’ previous PV devices.

19

Characterisation of nano-thin film GO/TiO2 layers for Kretschmann-based surface plasmon resonance visible sensing using FDTD method

Khairulazdan N. B., Mohamed R., Berhanuddin D. D., Menon P. S.

Optica Applicata

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2021

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Vol. 51, nr 4

579--587

EN

Kretschmann-based surface plasmon resonance (K-SPR) is suitable for biomolecular sensing which provides label-free and quick detection results with real-time analysis. In this work, we have investigated the effect of graphene oxide (GO) with titanium dioxide (TiO2) thin films that are placed in hybrid above metal layers such as gold (Au), silver (Ag) and copper (Cu) with the presence of chromium (Cr) as an adhesive layer. The thickness of the Au, Ag and Cu metal thin films were optimized to 40, 30 and 30 nm, respectively, with a fixed thickness of GO of 2 nm and TiO2 of 1.9 nm. The sensing was evaluated for SPR excitation at three different visible wavelengths of 633, 670 and 785 nm. The performance of sensing was analyzed based on the reflectance intensity and full-width at half-maximum (FWHM) of the spectrum using the finite-difference time-domain (FDTD) method. The sensitivity was calculated for analyte sensing in dielectric mediums of air versus water. The sensitivity increment percentage (%∆S ) was determined when comparing analyte detection using Cr/metal and Cr/metal/GO/TiO2 sensor structures. The highest sensitivity of 94.51 deg/RIU was achieved for Cr/Cu/GO/TiO2 K-SPR sensor at 633 nm wavelength.

20

Innowacyjne cementowe kompozyty fotokatalityczne

Jackiewicz-Rek Wioletta, Chilmon Karol

Materiały Budowlane

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2021

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nr 3

48--50