Wyniki wyszukiwania - BazTech

1

Antibacterial effect of polylactic-co-glycolic acid/selenium nanocomposite against dental biofilm

Safaei Mohsen, Khaleseh Farnoosh, Ahmadi Saba, Mobarakeh Mohammad Salmani, Law Douglas, Wong Ling Shing, Ravinder D., Nhlapo Amos, Hashim Mohd, Parveen Azra

Polimery

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2025

|

Vol. 70, nr 3

186--193

EN

To determine the optimal conditions for obtaining poly(lactic-co-glycolic) acid with selenium (PLGA/selenium) nanocomposites the Taguchi method was used. FT-IR, Raman spectroscopy, XRD and FESEM analysis confirmed the nanocomposites’ structure. The nanocomposite containing 6 mg/mL of selenium obtained in the process where the mixing time was 75 min showed the highest antibacterial activity against Streptococcus mutans. The obtained nanocomposites are an innovative approach to im-proving oral health and can be used as antibacterial materials for medical and dental applications.

PL

Metodą Taguchi określono optymalne warunki otrzymywania nanokompozytów poli(kwasu mlekowego-co-glikolowego) z selenem (PLGA/selen) i oceniono ich aktywność przeciwbakteryjną przeciwko Streptococcus mutans. Najwyższą aktywnością przeciwbakteryjną charakteryzował się nanokompozyt zawierający 6 mg/mL selenu (czas mieszania 75 min). Strukturę nanokompozytu potwierdzono metodą FT-IR, spektroskopii Ramana, XRD i FESEM. Nanokompozyty PLGA/selen stanowią nowe podejście do poprawy zdrowia jamy ustnej i mogą być stosowane jako materiały przeciwbakteryjne do zastosowań medycznych i stomatologicznych.

2

Radiation shielding performance of high entropy alloys and derived nanomaterials towards nuclear irradiation/electromagnetic interference environments - fundamentals and technicalities

Kausar Ayesha

Advances in Materials Science

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2025

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Vol. 25, nr 2(84)

73--103

EN

Recently, we note, high entropy alloys have attained incalculable research curiosity owing to remarkable elemental combinations, microstructural features, phase structure/stability, and superior physical characters mainly mechanical, thermal, and corrosion resistance under extreme working conditions. Interestingly, these materials have been found capable of sustaining the mechanical and anticorrosion properties at considerably high temperatures. In addition to the energy, engineering, and biomedical fields, high entropy alloys have been frequently explored for radiation protection applications. In nuclear sector, high entropy alloys and nanocomposite alloys exhibited worthy radiation defense towards wide ranging energetic particles including fast neutrons, gamma rays, electrons/ions, and other radionuclides. Consequently, plentiful high entropy alloys and related nanomaterial (nanocarbons, polymers, inorganic) designs have been found promising as functional bulk material/coatings for nuclear radiation as well as electromagnetic interference defiance. Accordingly, the appropriate experimental as well as theoretical approaches have been applied to study the structure, durability, and nuclear shielding effectiveness. In this context, various active mechanisms have been reported, including the micro-level changes, phase transformations, reduced thermal conductivity, and related radiation induced effects. Henceforth, this all-inclusive state-of-the-art overview, we believe, enlightens the significance of high performance high entropy alloys and nanomaterials for technical radiation defense applications against nuclear and electromagnetic interfering irradiations. In addition to radiation shielding parameters, the next generation high entropy alloy shields have been surveyed for synergistic mechanical, thermal, and anticorrosion features desirable against extreme nuclear/fission reactors environments.

3

Graphene quantum dots in conjugated and rubbery matrices - stipulations and physical/technical attributes

Kausar Ayesha

Advances in Materials Science

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2025

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Vol. 25, nr 1(83)

5--36

EN

This leading-edge overview delivers an all-inclusive knowledge on fundamentals, state-of-the-art, and technicalities of two important polymer categories filled with graphene quantum dots, namely conjugated polymer/graphene quantum dots and rubber/graphene quantum dots nanocomposites. According to the literature up till now, facile and efficient fabrication methods, like in situ polymerization, solution mixing, melt blending, etc. have been reported for these graphene quantum dots derived hybrids. The ensuing graphene quantum dots based nanocomposites were inspected for microstructural, electrical conductivity, charge transportation, thermal/mechanical resistance, fluorescence properties, and allied valuable physical features. Incidentally, we notice promising applications of inimitable categories of conjugated polymer/graphene quantum dots and rubber/graphene quantum dots hybrids for gas/molecular/piezoelectric sensors, supercapacitors, and biomedical areas. Nevertheless, due to limited reports on applied sides of graphene quantum dots filled conjugated/rubbery matrices, future research attempts seem indispensable to resolve challenges of optimized/controlled processing and also to unveil structure-property-performance links and synergistic mechanisms for developing next generation industrial level conjugated polymer/graphene quantum dots and rubber/graphene quantum dots nanocomposites.

4

Zastosowanie mezoporowatego bioaktywnego szkła w procesie regeneracji tkanki kostnej

Michał Moritz, Małgorzata Geszke-Moritz

Przemysł Chemiczny

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2024

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T. 103, nr 10

1168--1171

PL

Dokonano literaturowego przeglądu dotyczącego zastosowania mezoporowatego szkła krzemionkowo-wapniowo-fosforanowego jako biomateriału stosowanego w leczeniu chorób tkanki kostnej. Mezoporowate bioaktywne szkła mogą pełnić funkcję szkieletową i podpórkową dla powstających tkanek oraz służyć jako nośniki substancji leczniczych, jonów metali czy czynników wzrostu stosowanych w regeneracji tkanki kostnej. Unikatowe właściwości fizykochemiczne oraz biologiczne, takie jak rozwinięta powierzchnia oraz biokompatybilność sprawiają, że materiały te stosowane są w inżynierii tkankowej.

EN

A review, with 21 refs., of use of mesoporous SiO₂-CaO-P₂O₅ glasses as the biomaterials for bone tissue regeneration. They not only play a skeletal and supporting role for tissues but also are as carriers for drugs and metal ions as well as growth factors in the process for tissue regeneration. Unique phys., chem. and biol. properties (large surface and biocompatibility) make the materials useful in tissue engineering.

5

Study the effect of zinc oxide nanoparticles on degradation, antibacterial, thermal and morphological properties of polyvinyl alcohol films

Sabr Ohood Hmaizah, Obaid Massar Najim, Al-Mutairi Nabeel Hasan, Krynke Marek, Mielczarek Krzysztof

Production Engineering Archives

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2024

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Vol. 30, Iss. 4

528--536

EN

In this study, a film was prepared from polyvinyl alcohol (PVA) and zinc oxide (ZnO) nanoparticles (nano-ZnO) via the casting method. Nanoparticles were added to PVA biopolymer to create reinforced biocomposite films with different loading contents (2, 4, and 6 wt.%), and they were tested by performing the following assays: the FTIR test, the antibacterial, soil burial test, DSC, AFM, and SEM. The results showed an improvement of the membranes in the antibacterial properties for both Escherichia coli (E. coli, Gram-negative) and Staphylococcus aureus (S. aureus, Gram-positive) when nano-ZnO was added. The biodegradation through weight loss was observed for all samples, and the results showed that the weight loss increased with the increase in ZnO nanoparticle content from 2% to 6% wt. The DSC results showed that the addition of ZnO led to an increase in Tg, and increasing the degree of glass transition led to an increase in the degradation rate. In the FTIR results, only physical interference was observed; no chemical interference was evident. The AFM results showed some agglomerations of nano-ZnO in the PVA matrix led to an increase in the surface roughness of the PVA/nano-ZnO film.

6

Vibration analysis of asymmetric sandwich rotating FG porous discs coated with agglomerated nanocomposite facesheets

Jazi Farnoosh Rasooli, Amir Saeed, Arshid Ehsan

Archives of Civil and Mechanical Engineering

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2024

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Vol. 24, no. 4

art. 201, 1--20

EN

The present research conducts free vibration analysis of annular rotating discs made from functionally graded porous materials, and nanocomposite reinforced carbon nanotubes face sheets. Pores distribution in the porous core is considered based on three different patterns, namely Nonsymmetric, Symmetric, and Monotonous ones across the thickness, and also, carbo nanotube dispersion in the face sheets is investigated randomly by considering their agglomeration effect. Kinematic relations of the mentioned structure regarding the shear deformation effects and based on the first-order theory are described, and then, variations of strain and kinetic energies by considering rotation via the calculus variation method are calculated. To extract the governing motion equations and associated boundary conditions, Hamilton's principle is employed, and then they are solved with the aid of the generalized differential quadrature method. After ensuring the correctness of the results obtained from the scripted code by comparing them in the simpler state with the previous research, the effect of different parameters such as pores’ distribution patterns, carbon nanotubes dispersion patterns and their agglomeration, core and face sheets thickness, and other parameters on the natural frequencies of the structure is investigated. Considering the obtained results, it can be found that increasing the porosity leads to a slight increment in the natural frequencies, generally, and increasing the carbon nanotubes’ mass fraction leads to significant enhancement in them. The outcomes of this study can be used in different industries, such as aerospace, military, and marine industries.

7

Microstructure, mechanical and tribological properties of AA5083‑TiO2 nanocomposite by multi‑pass friction stir processing

Karmiris-Obratański Panagiotis, Papantoniou Ioannis G., Leszczyńska-Madej Beata

Archives of Civil and Mechanical Engineering

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2024

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Vol. 24, no. 4

art. 209, 1--20

EN

This study examines the impact of Friction Stir Processing (FSP) with TiO2 nanoparticle incorporation on the microstructural, mechanical, and tribological properties of AA5083 Metal Matrix Composites (MMCs). It offers a detailed analysis of the alterations in the alloy’s characteristics due to FSP. Microstructural examination was conducted using optical microscopy (OM) and scanning electron microscopy (SEM). Significant findings include the microstructural refinement where TiO 2 nanoparticle addition during FSP shrank the grain size from 20 to 3 μm after one pass, which then rose to 7 μm following four passes. Mechanical properties, specifically microhardness and tensile strength, were assessed. Results indicated that after four FSP passes, the material can reach a yield strength of 192 MPa and an ultimate tensile strength (UTS) of 359 MPa, alongside a consistent microhardness of 103 HV0.1. Furthermore, it was observed that increasing FSP passes enhances energy absorption, although it remains lower than that of the base material. Analysis of fracture and wear mechanisms has led to the conclusion that with more passes, fracture mechanisms transition to a mix of ductile and brittle behaviors, and the friction coefficient decreases by up to 22.95%.

8

Imprints of graphene nanocomposites towards energy storage potential of lithium ion batteries—state of the art and perspectives

Kausar Ayesha, Ahmad Ishaq

Advances in Materials Science

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2024

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Vol. 24, nr 2(80)

35--60

EN

This state-of-the-art article is designed to cover essential aspects of graphene based nanomaterials for energy storage purposes. Graphene is, a unique nanocarbon, one atom thick nanosheet made up of sp2 hybridized carbon atoms. Graphene has been focused for various technical energy related devices and systems owing to remarkable structure and properties. In energy storage applications, graphene has been applied for varying devices like supercapacitors, fuel cell and batteries. Important utilization of graphene and derived nanocomposites have been observed for lithium (Li) ion batteries. In this context, graphene has been found to offer superior surface area, electron conduction, electrochemical properties, charge or energy density, reversible capacity, rate capacity, cyclic stability, charge-discharge behavior, and other progressive characteristics for effectual energy or charge storage. In addition, graphene derived nanomaterials have been researched for structural, morphological, mechanical, thermal, and other physical characteristics. Hence, graphene and nanocomposites have been reported as efficient Li ion battery electrode or electrolyte material. Future progress on designing new efficient graphene derived nanocomposites and three dimensional graphene based nanomaterials may overcome the challenges towards the formation of high performance battery electrode or electrolyte materials.

9

Competence of carbonaceous fibers/nanofillers (graphene, carbon nanotube) reinforced shape memory composites/nanocomposites towards aerospace — existent status and expansions

Kausar Ayesha

Advances in Materials Science

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2024

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Vol. 24, nr 3(81)

30--55

EN

Shape memory or stimuli responsive polymers have established a unique grouping of smart materials. The technical merit of these polymers has been evaluated in aerospace sector, since last few decades. Particularly, the stimuli responsive polymers render inherent competences to recuperate the structural damages in exterior/interior space architectures. In this context, both the thermoplastics as well as thermosetting polymers depicted essential stimuli responsive behaviour. As interpreted in this state-of the-art review, the carbonaceous reinforcement like carbon fibers and nano-reinforcements including nanocarbons (graphene, carbon nanotube) have been employed in the shape recovering matrices. The performance of ensuing shape retrieving aerospace materials was seemed to be reliant on the polymer chain crosslinking effects, filler/nanofiller dispersal/alignment, microstructural specs, interfacial contour and interactions, and processing techniques used. Consequently, the shape actuations of polymer/carbon fiber composites were found to be instigated and upgraded through the inclusion of nanocarbon nano-additives. The ensuing high-tech shape memory composites/nanocomposites have anomalous significance for various aero-structural units (fuselage, wings, antennas, engines, etc.) due to prevention of possible thermal/shock/impact damages. Future implications of carbonaceous shape memory composites/nanocomposites in aerospace demands minimizing the structure-property-performance challenges and large scale fabrication for industrial scale utilizations. In this way, deployment of carbonaceous nanofiller/filler based composites revealed enormous worth due to low density, anti-fatigue/wear, anti-corrosion, non-flammability, self-healing, and extended durability and long life operations. However, there are certain challenges associated with the use of nanocarbons and ensuing nanocomposites in this field markedly the adoption of appropriate carbon fiber coating technique, aggregation aptitude of nanocarbons, additional processing steps/cost, nanoparticle initiated invisible defects/voids, difficulty in machinability operations due to presence of nanoparticles, and corrosion risk of composite structures in contact with metal surfaces. By overcoming these hinderances, nanoparticles modified carbon fiber based composites can be promising towards a new look of upcoming modernized aerospace industry.

10

Zastosowanie nanodomieszek w materiałach izolacyjnych

Dąda Anna, Błaut Paweł

Przegląd Elektrotechniczny

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2023

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R. 99, nr 1

185--189

PL

Nieustannie rosnące zapotrzebowanie na energię elektryczną o wysokiej jakości wymaga zwiększenia niezawodności jej przesyłu i dystrybucji, co skutkuje koniecznością poprawy właściwości materiałów izolacyjnych. Obecnie na całym świecie prowadzone są prace badawcze mające na celu uzyskanie nowych, materiałów izolacyjnych o lepszych parametrach, wśród których wymienia się nanokompozyty. Artykuł przedstawia przegląd dotychczasowych osiągnieć w zakresie nanodielektryków oraz aktualnych problemów zastosowania nanodomieszek/ nanowypełniaczy w materiałach izolacyjnych. Opisano właściwości materiałów izolacyjnych, w aspekcie m.in.: modyfikacji przenikalności elektrycznej, wpływu na rozkład ładunku przestrzennego, odporności na narażenia długotrwałe, zwiększenia wytrzymałości elektrycznej oraz optymalizacji interfazy polimer-nanowypełniacz.

EN

The ever-growing demand for high-quality electricity requires increasing the reliability of its transmission and distribution, which results in the need to improve the properties of insulating materials. Currently, research is carried out all over the world to obtain new, insulation materials with better parameters, including nanocomposites. The article presents an overview of the current achievements in the field of nanodielectrics and the current problems of using nanoparticles / nanofillers in insulation materials. The properties of insulating materials were described in terms of, among others: modification of permittivity, influence on the distribution of space charge, resistance to long-term stresses, increased electrical strength and optimization of the polymer-nanofiller interphase.

11

Experimental study of nano-composite materials on vibration responses

Mobark Haidal Faisal Helal, Fahdel Essam Z., Hussein Mustafa Turki, Mohamad Barhm

Diagnostyka

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2023

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Vol. 24, No. 3

art. no. 2023312

EN

This paper present of experimental and numerical study of nano Al2O3 cantilever beam for forced vibration, addressing an unexplored area in the existing literature. The proposed nano composite cantilever beam is modeled with hole and crack. The study is based on history loading calculation and composite morphology a global parameter, the transverse crack in nano composite cantilever beam was studied and analyzed experimentally using a four-channel dynamic signal acquisition (NI 9234) module for making high-accuracy measurements and its ideal for vibration applications. The relationship between the dispersion and interaction of the alumina nanoparticles within the cantilever beam and morphology of the solid, hole and crack composite has been identified. Furthermore, the influence of particles Al2O3 at different concentrations (0%, 1%, 3% and 4%) have been studied respectively. Supporting results proved that the crack and hole depth increases with increases of history loading. Nanoparticles dispersed within the specimen can increase energy dissipation during vibration, leading to improved damping characteristics. For future work, it is recommended to utilize statistical frequency domain input, such as Power Spectral Density (PSD), for assessing the structural response instead of employing time history loading.

12

Comparative performance assessment of nano-composite cathode of lmso-bscmf for low temperature solid oxide fuel cell applications

Subhashini P.V.C.K., Rajesh K.V.D.

Composites Theory and Practice

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2023

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R. 23, nr 4

235--238

EN

The development of novel cathode materials for low temperature solid oxide fuel cell (SOFC) applications is one of the significant research areas in materials engineering. In the current work, composite cathode materials were prepared by two different modes and the fuel cell performance was assessed using a gadolinium-doped ceria (GDC) electrolyte. Nanocomposite cathodes were fabricated using a lanthanum strontium manganite oxide (LSMO) powder of a 50-100 nm particle size and Ba0.5Sr0.5(Co0.2Mg0.8)0.2Fe0.8O3 (BSCMF) powder of a 1 μm particle size. The cathodes were prepared as layered composites and mixed composites. The electrochemical performance of the symmetric cells was investigated by electrochemical impedance spectroscopy (EIS) at the intermediate temperature of 700°C using air atmosphere. The cathode film coating on the electrolyte was sintered at three different temperatures (900, 950 and 1000°C) and the cell performance was assessed at 700°C. Lower polarization resistance (RP) values were recorded for the cell produced at 900°C. The RP of the nano-composite cathodes was measured as lower (2.72 Ω-cm2 for the layered composites and 1.76 Ω-cm2 for the mixed composites) compared with LSMO. Hence, the results demonstrate the potential of using an LSMO-BSCMF composite in the mixed mode as a cathode for low temperature SOFCs to achieve a lower polarization potential.

13

Leading-edge polymer/carbonaceous nano-reinforcement nanocomposites — opportunities for space sector

Kausar Ayesha, Ahmad Ishaq

Advances in Materials Science

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2023

|

Vol. 23, nr 4(78)

99--122

EN

Carbonaceous or nanocarbon nano-reinforcement nanocomposites have been found as emergent candidates for aerospace industry. Consequently, the multifunctional nanocomposites have been fabricated using marvelous nanocarbon nanostructures like graphene, carbon nanotube, fullerene, carbon black, etc. Manufacturing techniques have also been engrossed for the formation of high performance engineering nanocomposites having fine strength, heat stability, flame resistance, and other space desired features. These practices include solution, in situ, and melt procedures, on top of specific space structural design techniques, for the formation of aerospace structures. The aerospace related material property enhancements using various carbonaceous nano-reinforcements depends upon the type of nanocarbon, dimensionality, as well as inherent features of these nanostructures (in addition to the choice of manufacturing methods). Furthermore, carbon nano-reinforcements have been filled, besides carbon fibers, in the epoxy matrices. Nanocarbon coated carbon fibers have been filled in epoxy resins to form the high performance nanomaterials for space structures. The engineering features of these materials have been experiential appropriate for the aerospace structures. Further research on these nanomaterials may be a key towards future opportunities in the aero systems. Additionally, the explorations on structure-property relationships of the carbonaceous nanocomposites have been found indispensable for the development of advanced aerospace structures.

14

Combined axial and lateral stability behavior of random checkerboard reinforced cylindrical microshells via a couple stress-based moving Kriging meshfree model

Liu Hongwei, Safaei Babak, Sahmani Saeid

Archives of Civil and Mechanical Engineering

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2022

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Vol. 22, no. 1

art. no. e15, 2022

EN

In this investigation, a size-dependent numerical solution methodology is devised to analyze nonlinear buckling and postbuckling of cylindrical microsized shells made of checkerboard randomly reinforced nanocomposites subjected to a combination of axial and lateral compressions. To accomplish this purpose, the modified couple stress elasticity continuum is formulated within the third-order shear flexible shell model. Using a probabilistic-based homogenization plan in conjunction with the Monte-Carlo simulation, the effective mechanical parameters of the randomly reinforced nanocomposites are captured. The established size-dependent problem is then numerically solved via using the moving Kriging meshfree technique having the ability to enforce the required boundary conditions straightly at the associated nodes without using any type of penalty technique. By tracing the nonlinear stability paths, it is revealed that for the both axial dominated and lateral dominated loading cases, the stiffening feature related to the rotation gradient tensor causes that the microshell endures higher shortening before the buckling phenomenon occurs. In addition, it is found that by increasing the length to width ratio of graphene nanofillers, the effect of combination of axial or lateral load increases a bit.

15

Investigating the effects of alumina nanoparticles on the impact resistance of polycarbonate nano-composites

Alavi Nia Ali, Amirchakhmaghi Saeed

Archive of Mechanical Engineering

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2022

|

LXIX, nr 3

431--454

EN

In this project, two types of treated and untreated alumina nanoparticles with different weight percentages (wt%) of 0.5, 1 and 3% were mixed with polycarbonate matrix; then, the impact ballistic properties of the nano-composite targets made from them were investigated. Three types of projectile noses -cylindrical, hemispherical, and conical, each with the same mass of 5.88 gr – were used in the ballistic tests. The results highlighted that ballistic limit velocities were improved by increasing the percentage of alumina nanoparticles and the treatment process; changing the projectile’s nose geometry from conical to blunt nose increases the ballistic limit velocity, and ultimately, by increasing the initial velocity of conical and hemispherical nosed projectiles, the failure mechanism of the targets changed from dishing to petalling; whereas for the cylindrical projectile, the failure mode was always plugging.

16

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

Dąda Anna, Błaut Paweł

Przegląd Elektrotechniczny

|

2021

|

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

Carbon nanotubes-based sensor for ammonia gas detection - an overview

Nurazzi N. M., Demon Siti Zulaikha N., Halim Norhana A., Mohamad Syakir I., Abdullah Norli

Polimery

|

2021

|

T. 66, nr 3

175--186

EN

A sensitive, selective and reliable sensing techniques for ammonia (NH3) gas detection have been highly demanded since NH3 is both a commonly utilized gas in various industrial sectors, and considered as a toxic and caustic agent that can threat human health and environment at a certain level of concentrations. In this article, a brief on the fundamental working principles of sensor specifications of the analytes detection techniques relying has been reviewed. Furthermore, the mechanism of NH3 detection and recent progress in the development of advanced carbon nanotubes (CNTs)-based NH3 gas sensors, and their performance towards the hybridization with the conductive polymers was comprehensively reviewed and summarized. Finally, the future outlook for the development of highperformance NH3 sensors was presented in the conclusions part.

PL

Amoniak (NH3) to gaz powszechnie stosowany w różnych sektorach przemysłu, jest toksyczny i żrący, a powyżej określonego poziomu stężeń może zagrozić ludzkiemu zdrowiu i środowisku, dlatego ciągle trwają poszukiwania czułych, selektywnych i niezawodnych metod wykrywania gazów amoniakalnych. W niniejszym artykule dokonano przeglądu specyfikacji i podstawowych zasad działania czujników stosowanych w technikach wykrywania takich analitów. Szczegółowo przeanalizowano też mechanizm wykrywania i niedawny postęp w opracowywaniu zaawansowanych czujników do wykrywania gazu NH3 , opartych na nanorurkach węglowych (CNTs), a także ich modyfikacje obejmujące hybrydyzację z polimerami przewodzącymi. Przedstawiono również perspektywy rozwoju wysoko wydajnych czujników NH3.

18

Experimental and numerical studies of fatigue properties of carbon/glass fiber/epoxy hybrid composites enhanced with nano TiO2 powder

Hunain Mustafa Baqir, Abass Basim A., Akhudair Jaafar Musa

Diagnostyka

|

2021

|

Vol. 22, No. 2

75--84

EN

The present work deals with the fatigue behavior of hybrid nanocomposites consisting epoxy strengthen by unidirectional carbon fibres, and/or woven roving glass fiber and TiO2 nanofillers. For this purpose, nanocomposite material was manufactured by mixing TiO2 nanoparticles with the epoxy using an ultrasonic mixer to insure complete dispersion of such particles in the base material. Different particle concentrations (1, 3, and 5) % wt. of TiO2 nanoparticles have been added to the epoxy. Different types of hybrid nano composite materials were manufactured by adding three layers of carbon fibers and/or woven roving glass fiber to the prepared epoxy nanocomposite materials with a constant weight fraction of 30%. The laminated hybrid nanocomposite materials were then prepared using hand lay-up technique using a vacuum device. For experimental purposes tensile and fatigue test specimens have been manufactured according to ASTM-D3039 and ASTM D 3479/D 3479M-96, respectively, while ANSYS19 program was used to analyze the fatigue behavior of such materials numerically. Tensile tests were carried out at room temperature while fatigue tests has been carried out at constant stress ratio (R=-1). Scanning electron microscope (SEM) was used to identify the underlying mechanisms for fatigue failure and the progressive of damage growth. For each test, three specimens were tested and the average magnitude for each property was taken. The results obtained indicated that the hybrid nanocomposite (EP+C/C/C+3% TiO2) has the highest fatigue limit and tensile strength in comparison with the other tested material, while the SEM results showed that the composite failed by a brittle way. It has been also generally observed that the addition of (TiO2) nanoparticles has a positive effect on the fatigue behaviour of the such materials.

19

Influence of montmorillonite nanoparticles on thermal and mechanical properties of carbon-carbon hybrid composites based on phenolic-formaldehyde resin

Kateusz Filip, Korzec Tomasz, Zambrzycki Marcel, Cherniushok Oleksandr, Gubernat Maciej

Composites Theory and Practice

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2021

|

R. 21, nr 3

96--101

EN

In this study, the effect of the addition of K-10 montmorillonite (MMT) nanoparticles on the mechanical and thermal properties of carbon-carbon composites were investigated. The composites were obtained using self-made prepregs with plain and twill 2/2, 600 g/m2 carbon fabric and phenolic-formaldehyde resin. The composites were obtained by the hot pressing technique, followed by carbonization in an inert argon atmosphere. Modified samples of the composites contained 5 wt.% MMT, homogenously dispersed in the ceramic carbon matrix. The mechanical properties, thermal conductivity and thermal capacity of the composites were determined. Raman spectroscopy and Fourier transform infrared spectroscopy were used to investigate the carbon matrix composition and structure. The results show that the addition of MMT nanoparticles increased Young’s modulus by 48%, Kirchoff’s modulus by 80.2%, but did not change the interlaminar shear strength nor the bending strength. The MMT influenced the carbon microstructure, changed the ID//IG Raman ratios, as well as the matrix composition. The addition of MMT also increased the low temperature regime of thermal conductivity and diffusivity of the samples.

20

Synteza nowych nanokompozytów chitozan/modyfikowany zeolit i ich wpływ na właściwości mechaniczne zapraw cementowych

Karakuş Selcan, Karapınar Işıl Sanrı, Pehlivan Ahmet Onur, Özsoy Özbay Ayşe Elif, Yazgan Utku

Cement Wapno Beton

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2021

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R. 26, nr 6

531--544

PL

W pracy przedstawiono nowy nanokompozyt zawierający biodegradowalny chitozan [CS] i modyfikowany zeolit [mZeo] jako eko-nanododatek do cementu oraz oceniono jego wpływ na właściwości mechaniczne zapraw cementowych. Proponowany nanokompozyt otrzymano dzięki synergicznej metodzie sonikacji mikrofalowej, a morfologię powierzchni i skład chemiczny nanokompozytów mZeo i CS/mZeo określono za pomocą SEM, FTIR, XRF i BET. Zbadano wytrzymałość na ściskanie i zginanie zapraw cementowych zawierających mZeo i CS/mZeo w ilości 0, 0,2, 0,5, 1 i 2 % masy cementu. Wyniki badań doświadczalnych wykazały poprawę wytrzymałości zapraw zawierających proponowany nanokompozyt. W niniejszej pracy po raz pierwszy podjęto próbę zastosowania zeolitu w nanoskali w kompozytach cementowych, a uzyskane dotychczas wyniki są bardzo obiecujące. Stwierdza się zatem, że proponowany nanokompozyt ma duży potencjał do zastosowania jako alternatywny eko-nanododatek do kompozytów cementowych.

EN

In this paper, a novel nanocomposite containing biodegradable chitosan [CS] and modified zeolite [mZeo] was introduced as a cement eco-nano additive and its effects on the mechanical properties of cement mortars were evaluated. The proposed nanocomposite was prepared by using a synergistic sonication-microwave method. The surface morphology and chemical compositions of mZeo and CS/mZeo nanocomposites were determined using SEM, FTIR, XRF, and BET. Compressive and flexural strength of cement mortars containing mZeo and CS/mZeo in ratios of 0%, 0.2%, 0.5%, 1% and 2% by mass, were investigated. Experimental results showed a significant improvement in the mechanical properties of mortars containing the proposed nanocomposite. The use of nanoscale zeolite in cementitious composites was attempted for the first time within this study and the results so far have been very promising. Therefore, it is concluded that the proposed nanocomposite has great potential to be used as an alternative eco-nano additive, for cementitious composites.