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1

Przygotowanie i charakterystyka kompozytowego materiału izolacyjnego nano-MgO/polipropylen do budowy linii przesyłowych prądu stałego ultrawysokiego napięcia

Kang Xuefu, Pei Xudong, An Jianzhen, Liang Daping, Ling Shuqi, Wang Yuping

Przemysł Chemiczny

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2024

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T. 103, nr 1

97--103

PL

Nanocząstki MgO (nano-MgO) zostały przygotowane przez wspomagane mikrofalowo kalcynowanie Mg(OH)₂ i wykorzystane do modyfikacji właściwości matrycy polipropylenowej (PP) (zawartość nanocząstek do 2% mas.). Dodatek nano-MgO do matrycy PP zawierającej kopolimer etylen/octan winylu spowodował wzrost jej rezystywności objętościowej z 1,73∙10¹⁴ Ωm do 2,85∙10¹⁴ Ωm, ale miał tylko niewielki wpływ na natężenie pola przebicia materiału. Dodatek nano-MgO spowodował również poprawę makroskopowych właściwości elektrycznych materiałów w porównaniu z czystymi próbkami PP. Po dodaniu 0,5% mas. nano-MgO gęstość ładunku przestrzennego kompozytu PP pozostała niezmieniona na poziomie 0,81 C/m² , a gdy zawartość nano-MgO wynosiła 1% mas., gęstość ładunku przestrzennego była najniższa. Wytrzymałość na rozciąganie i wydłużenie przy zerwaniu kompozytowych materiałów izolacyjnych nano-MgO/PP były nieco niższe niż w przypadku czystego PP, ale ogólny spadek nie był znaczący. Badanie właściwości mechanicznych potwierdziło możliwość zastosowania kompozytowych materiałów izolacyjnych nano-MgO/PP w praktyce przemysłowej.

EN

Nano-MgO particles were prepd. by microwave-assisted calcining Mg(OH)₂ and used for modifying properties of the polypropylene (PP) matrix (nano-MgO content up to 2% by mass). The addn. of nano-MgO to the ethylene/vinyl acetate copolymer-cong. PP matrix, resulted in an increase its volume resistivity form 1.73·10¹⁴ Ωm up to 2.85·10¹⁴ Ωm but had only a small impact on the breakdown field strength of the material. The addn. of nano-MgO resulted also in improving the macroscopic elec. properties of the materials when compared with pure PP samples. When 0.5% by mass nano-MgO was added, the space charge d. of PP composite remained unchanged at 0.81 C/m² , and when the content of nano-MgO was 1% by mass, the space charge density was the lowest. The tensile strength and elongation at break of nano-MgO/PP composite insulation materials were slightly lower than that of pure PP, but the overall decline was not significant. The study on mechanical properties conformed the applicability of the nano-MgO/PP composite insulating materials in the industrial practice.

2

Development of Environmentally Friendly and Intelligent Food Packaging Bio-Nanocomposite Films

Hasan Muhammad, Utami Annisa, Purma Raiyana, Syahrial Syahrial, Rahmayani Ratu Fazlia Inda, Zulfadli Zulfadli

Ecological Engineering & Environmental Technology

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2024

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Vol. 25, iss. 3

155--164

EN

Researchers are actively exploring biodegradable biocomposite films as environmentally friendly packaging solutions. Increasing consumer demand for a healthy and secure lifestyle led to a serious recent study into the development of intelligent food packaging bio-nanocomposite films aiming not only contribute to sustainability but also possess advanced functionalities through the integration of nanotechnology and intelligent features. This research focuses on the development of active and pH-responsive bio-nanocomposite films by incorporating various concentrations of SPE anthocyanins into the nanoparticle of the CH-PSPS matrix using the solvent-casting method. Thorough examination and characterization of the films revealed a smooth and compact surface, indicative of a uniform distribution of SPE anthocyanins within the matrix as observed through AFM analysis. The inclusion of SPE anthocyanins resulted in a significant increase in antioxidant activity, ranging from 16.37% to 26.44%. Additionally, all films containing SPE anthocyanins exhibited excellent UV barrier properties and demonstrated sensitivity to pH levels within the range of 1 to 10 in buffer solutions. Moreover, the films effectively preserved the freshness of the shrimp during storage. Consequently, these developed films showcase promising potential as active and intelligent packaging materials for food products.

3

Allometry of nanoparticles in diesel-biodiesel blends for CI engine performance, combustion and emissions

Ahmed Mohd Mujtaba, Pali Harveer Singh, Khan Mohammad Mohsin

Archives of Thermodynamics

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2024

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Vol. 45, no 1

99--108

EN

Most countries in the world are facing two major challenges, one is the increase in the demand for energy consumption difficult to fulfill because of limited fossil fuel, and the second is the emission norms specified by many countries. Various methods are adopted to reduce emissions from engines but that leads to sacrificing the performance of CI engines. To eradicate this problem in the present study, the nanoparticles like (TiO2) are used with different particle sizes 1030 nm, 3050 nm and 5070 nm induced in B20 (20% biodiesel and 80% diesel) with the constant volume fraction of 100 ppm, and utilized in the diesel engine without any modifications. The results showed that the incorporation of TiO2 nanoparticles improves the combustion of hydrocarbons and reduces the emissions of CO, unburned hydrocarbon concentration, NOx and soot. Moreover, among three sizes of the nanoparticles, those with size 3050 nm showed interesting results with the reduction in brake-specific energy consumption, NOx, smoke and HC by 2.9%, 16.2%, 35% and 10%, respectively, compared to other blends used in the study, and hence the blend with the nanoparticle of size 3050 nm is expected to be a more promising fuel for commercial application in CI engines.

4

Performance and emissions characteristics of a diesel engine fueled by carbon nanoparticle-blended diesel and biodiesel

Slavinskas Stasys, Jokubynienė Vida

Transport Problems

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2023

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T. 18, z. 2

87--96

EN

Carbon-based nanomaterials have excellent properties and can be used in fuels to reduce emissions and improve engine performance and fuel economy. Due to their unique thermal conductivity properties, nanoparticles are widely used in various ways. The current article analyzes research results on the influence of carbon nanoparticles on the working characteristics and emissions of internal combustion engines powered by diesel and biodiesel. Fuels were mixed with the nanomaterial CPL at different concentrations (50, 100, and 150 ppm). This article analyzes the influence of nanomaterial (carbon wafers) in diesel engines using diesel and biodiesel to reduce emissions and fuel consumption, evaluates the volume of nanomaterials as a fuel additive needed to improve emission performance, and investigates the problem of the practical application of nano-fuel (i.e., regarding dosage and stability).

5

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.

6

Impact of Zinc Oxide Nanoparticles on Seed Germination Characteristics in Rice (Oryza sativa L.) Under Salinity Stress

Singh Abhishek, Sengar Rakesh Singh, Rajput Vishnu D., Agrawal Shreni, Ghazaryan Karen, Minkina Tatiana, Al Tawaha Abdel Rahman Mohammad, Al Zoubi Omar Mahmoud, Habeeb Talaat

Journal of Ecological Engineering

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2023

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Vol. 24, nr 10

142--156

EN

An exciting new window of opportunity has opened up for environmentally responsible farming with the advent of the nanotechnology era: the role of nanoparticles (NPs) to mitigate abiotic stresses. NPs have unique physiochemical characteristics that make them an attractive study subject. Rice growth and yield are severely inhibited by salinity, a major detrimental abiotic factor. However, the impact of NPs on rice seeds germination characteristics and physio-biochemical phenomena under salt stress conditions remains poorly understood. Accordingly, we intended to look at how zinc oxide nanoparticles (ZnO-NPs) affected germination processes and the early seedling stage while the rice plants (Kargi and CSR 30 rice genotypes) were put under salinity stress. Different germination characteristics parameters were considered, e.g., germination percentage (GP) relative seed germination rate (RGR), and seed vigour index (SVI) determined after eight days of treatment with ZnO-NPs at a concentration of 50 mg/L on rice seed. After passing the germination test, the seeds were placed in Hoagland hydroponic solution and given another week of ZnO-NPs treatment to evaluate the seedling growth and phyto-biochemical characteristics, such as shoot height and root length, inhibition percentage of shoot height and root length, chlorophyll and carotenoid stability index, chlorophyll and carotenoid inhibition percentage, malondialdehyde (MAD) content and antioxidant enzymatic activities (SOD, APX).This investigation demonstrated that 50 mg/L ZnO-NPs have the potential to alleviate the effect of salt stress on rice genotypes during the germination stage.

7

A Review on Crop Responses to Nanofertilizers for Mitigation of Multiple Environmental Stresses

Singh Abhishek, Rajput Vishnu D., Al Tawaha Abdel Rahman Mohammad, Al Zoubi Omar Mahmoud, Habeeb Talaat, Rawat Sapna, Ghazaryan Karen, Minkina Tatiana

Ecological Engineering & Environmental Technology

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2023

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Vol. 24, iss. 7

280--296

EN

Over the past years, alterations in the environment have had an adverse impact on the global agricultural system, leading to difficulties in plant growth, physiology, and productivity due to non-living factors. These difficulties pose a significant risk to both global food security and agricultural advancement, necessitating innovative methods for long-term sustainability. Nanotechnology has emerged as a promising solution to address these difficulties by utilizing nanoscale products like nanofertilizers, nanofungicides, nanoherbicides, and nanopesticides. Nanoparticles provide distinct advantages in agriculture due to their small size, ability to easily penetrate cellular barriers, and efficient absorption by plants. Numerous studies have demonstrated that the application of nanoparticles can improve both the quantity and quality of crop yields, even when faced with various biological and environmental pressures. This research study primarily focuses on investigating the impact of non-living pressures on plants and examining how nanoparticles can help alleviate these effects. Additionally, it explores the molecular, metabolic, and anatomical adaptations that plants undergo to thrive in challenging environments. Nonetheless, it is essential to acknowledge that the widespread utilization of nanotechnology raises concerns regarding potential risks to the environment and human health.

8

Zastosowanie nanocząstek do modyfikacji cieczy elektroizolacyjnych stosowanych w transformatorach energetycznych

Szcześniak Dominik, Przybyłek Piotr

Przegląd Elektrotechniczny

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2022

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R. 98, nr 6

62--65

PL

Jedną z obecnie rozwijanych metod poprawy właściwości cieczy elektroizolacyjnych jest ich modyfikacja przy użyciu nanoproszków. Poprawa parametrów cieczy zależy od rodzaju zastosowanego nanoproszku, wielkości nanocząstek, jak również od sposobu preparacji nanocieczy. Aktualnie na świecie prowadzone są badania ukierunkowane głównie na poprawę wytrzymałości elektrycznej oraz przewodności cieplnej modyfikowanych cieczy bazowych. W artykule przedstawiono przegląd stosowanych nanomodyfikatorów, metody preparacji nanokoloidów oraz omówiono zagadnienia związane z ich stabilnością.

EN

One possibility to improve the parameters of insulating liquids is their modification by means of nanopowders. The improvement of the dielectric fluid parameters depends on the type and size of the nanopowder as well as on the method of nanofluid preparation. Research conducted around the world are mainly focused on improvement the electrical strength and thermal conductivity of modified insulating liquids. The article presents an overview of nanomodifiers, methods of nanocolloids preparation and the issues related to their stability.

9

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.

10

Application of mixed-nanoparticle coating as a novel simple method in generating speckle pattern to study small fields of view by digital image correlation

Aghdam Milad Zolfipour, Soltani Naser, Nobakhti Hadi

Archive of Mechanical Engineering

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2022

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LXIX, nr 1

45--58

EN

Digital image correlation (DIC) is a powerful full-field displacement measurement technique that has been used in various studies. The first step in the DIC is to create a random speckle pattern, where the spraying method is usually employed. However, creating an optimal pattern and modification in the spraying method is not convenient. Furthermore, the size of speckles which is not so small in spraying method, limits the minimum size of the field of study. In the present research, a convenient novel technique was introduced and investigated to generate a practical kind of speckle pattern with small speckles for evaluating smaller fields of view using nanoparticles. The pattern was created by spreading a mixture of different black and white nanoparticles. To this end, the black graphene oxide particles were mixed with white nanoparticles of titanium oxide, zirconium oxide and silicon to obtain three mixtures. Displacement tests show that the mixture of graphene and titanium provides the best DIC performance. More granularly, graphene and titanium were mixed at three different ratios to find the optimal combination. Subsequently, the accuracy of the new patterning method was analyzed via tensile testing and the results were compared against those of conventional method with various subset sizes.

11

g-C3N4/ Bio–synthesized silver nanoparticle for fluorometric bio-sensing of acetylcholinesterase and malathion

Ali Abdu Hussen

Advances in Materials Science

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2022

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Vol. 22, nr 3(73)

23--40

EN

Malathion is widely used in agriculture due to their high efficiency as insecticides. They are very toxic hazardous chemicals to both human health and environment even at low concentration. The detection of pesticides (malathion) at the low levels developed by the environmental protection agency (EPA) still remains a challenge. A highly efficient fluorescent biosensor based on g-C3N4/AgNPs for AChE and malathion detection is successfully developed by impregnation method. The structural and morphological properties of the nanocomposites were characterized by using powder X-ray diffraction (XRD), fourier- transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). The analysis confirmed that there is a strong interfacial interaction between g-C3N4 and AgNPs. The fluorescent responses show an increase in intensity upon the additions of AChE which indicates that AChE as enzyme was hydrolyzing the substrate ACh, with the increase in oxidative electron as the preferred route of reaction. The developed OFF-ON sensor immobilizes by Actylcholestrase (AChE) and use as new probe for malathion detection. In the absence of malathion, AChE−g-C3N4/AgNCs exhibit high fluorescence intensity. However, the strong interaction of the basic sites to malathion, causes fluorescence quenching via static quenching and Ag form aggregation on the surface of g-C3N4. The experimental parameter such as pH of buffer (pH=6), concentration of acetylcholine (1 mM) and malathion (500 μM) were optimized. The sensor was also more sensitive with Stern-Volmer quenching constants (KSV) of 3.48x10 3 M -1. The practical use of this sensor for malathion determination in Khat was also demonstrated. The obtained amount of malathion in Khat is 168.8 μM.

12

Nanocząstki w biokompozytach polimer – ceramika do regeneracji tkanki kostnej

Bartolewska Magdalena

Szkło i Ceramika

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2021

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R. 72, nr 4

28--30

PL

Medycyna regeneracyjna staje się szybko rozwijającą techniką w współczesnej biomedycynie. Coraz częściej na świecie są wykorzystywane nanocząstki do naprawiania i leczenia uszkodzonych komórek. Ten artykuł przeglądowy przedstawia wiedzę na temat kompozytów, składających się z polimeru oraz hydroksyapatytu, modyfikowanych nanocząstkami i ich zastosowaniami w medycynie regeneracyjnej.

EN

Regenerative medicine is becoming a rapidly developing technique in modern biomedicine. Nanoparticles are used increasingly to repair and heal damaged cells. The paper presents knowledge about the use of nanoparticles in the modification of polymer and hydroxyapatite composites and their applications in regenerative medicine.

13

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.

14

Nanofluid assistance in machining processes – properties, mechanisms and applications: a review

Grzesik Wit

Journal of Machine Engineering

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2021

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Vol. 21, No. 2

75--90

EN

A special group of hybrid assisted processes termed media-assisted processes which apply liquid media with special additives in the form of nanoparticles supplied to the cutting zone is overviewed. Special attention is paid to minimum quantity lubrication (MQL) technique with the use of nanofluids. In this review paper some important thermal and tribological effects resulting from the applications of various nanoparticles are outlined and compared. The MQL-nano cutting fluid mechanisms (rolling and ploughing) are described. In particular, some important quantitative effects concerning thermal and tribological behaviour of the cutting process as well as surface quality are presented.

15

Experimental Study on Dyeing Performance and Antibacterial Activity of Silver Nanoparticle-Immobilized Cotton Woven Fabric

Tania Imana Shahrin, Ali Mohammad, Bhuiyan Riyadh Hossen

Autex Research Journal

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2021

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Vol. 21, no. 1

45--51

EN

The purposes of the current research were to deposit the silver nanoparticles on the surface of a textile woven fabric and evaluate their dyeing performance and antibacterial activity. The synthesis of silver nanoparticle (Ag°) is done by the in situ method. Strong alkali is used to improve functionality of cellulose before the application of silver nitrate salt (AgNO3). The silver nanoparticle is formed by reduction of ascorbic acid. Various instrumental analyses are done to prove the formation of nanoparticles on the fabric surface. The morphology of nanodeposited fabric is characterized by using scanning electron microscope (SEM), elemental composition is done by energy dispersive spectroscopy, and crystallinity of nanoparticles is obtained by X-ray diffraction (XRD). Nanodeposited fabric is then dyed with direct dyestuff (Direct Red-89). Fourier transform infrared spectroscopy analysis is done to explore the bonding phenomena of un-dyed and dyed fabrics. The dyeing performance and antibacterial activity are examined on the colored fabric to investigate the dyed fabric quality after nanoparticle deposition. Results demonstrate the improvement of 54% of color strength and 11% of dye exhaustion with excellent antibacterial activity.

16

Synthesis and Characterization of MoO3 Nano Particle by Controlling Various Growth Conditions in Solution Combustion Method

Kwon Namhun, Lee Seyoung, Roh Jaeseok, Lee Kun-Jae

Archives of Metallurgy and Materials

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2021

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Vol. 66, iss. 4

991--995

EN

In this paper, synthesize MoO3 particles with various particle properties by control growth influence factors was mainly studied. The experimental conditions were established in molar ratio of Mo:urea and ph levels. The plate-type of MoO3 particles were formed without proceeding any established conditions, but the rod-shape particles were formed by adjusting molar ratio of mo:urea. Also, different ranges of the particle size were formed by adjusting experimental conditions. Through the results, it was confirmed that particles with a size in the range of 300 ~ 400 nm were obtained by adjusting precursor concentration and the micrometer size of particles were formed by increase ph levels. The properties of the particles formed accordingly by setting various factors that can affect the growth process of MoO3 particle was analyzed as variables and the particle growth behavior was also observed.

17

Numerical prediction of thermal performance of an electrocaloric device based on ceramic material

Kehileche Brahim, Chiba Younes, Tlemcani Abdelhalim, Henini Noureddine

Przegląd Elektrotechniczny

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2020

|

R. 96, nr 9

38--42

EN

The main objective of this work is to efficiency prediction and parameter optimisation of an electrocaloric refrigeration system based on ceramic materials (BaTiO3) and nanofluids (Al2O3, CuO). For this purpose, an electrocaloric device is used and studied. The principle consists in the heating and cooling of the ceramic material under the application and removal of electrical field respectively. The nanoparticles suspended in water increase the heat thermal between solid electrocaloric material and carried fluid, so we have much faster heat exchanges that cause an increase in coefficient of performance (COP) and temperature span; the temperature difference between the cold heat exchanger (CHEX) and the hot heat exchanger (HHEX). Indeed, the performances of these systems are strongly dependent on the interactions between the thermal, the fluidic and the electricity in order to be able to evaluate and optimize these systems in terms of cooling power, and the observation is that there are very few current studies in this area. Finally, a parametric study effected by using the COMSOL Multiphysics identified the characteristic quantities that have a significant influence on thermal behavior in electrocaloric refrigeration systems based nanofluids and ceramic material.

PL

Tematem artykułu jest analiza i optymalizacja systemu chłodzenia bazującego na materiale ceramicznym BaTiO3 i nanocieczy Al2O3, CuO. W tym celu analizowano element elektrokaloryczny I współczynnik wymiany ciepła CCP. Przedstawiono wyniki badań elementu jak I całego systemu chłodzenia.

18

Nanoscale dosimetric consequences around bismuth, gold, gadolinium, hafnium, and iridium nanoparticles irradiated by low energy photons

Mesbahi Asghar, Mansouri Elham, Mohammadzadeh Mohammad

Polish Journal of Medical Physics and Engineering

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2020

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Vol. 26, Iss. 4

225--234

EN

In the current study, nanoscale physical dose distributions around five potential nanoparticles were compared. Five potential nanoparticles including bismuth, gold, gadolinium, hafnium, and iridium nanoparticles in the form of a sphere with a diameter of 50 nm were simulated in a water medium. The MCNPX (2.7.0) Monte Carlo code with updated libraries was used for calculations of electron dose deposition and electron flux in water from 25 nm up to 4000 nm with a step of 25 nm. Also, secondary electron spectra after irradiation of nanoparticles with mono-energetic photons with energies of 30, 60, 100 keV were derived. The nano-scale distance-dose curves showed a very steep gradient with distance from nanoparticle surface up to 60 nm and after this point, a gradual decrease was seen. The dose deposition characteristics in the nano-scale were dependent on the type of nanoparticle as well as photon energy. Our results concluded that for each photon energy in the energy range of 30-100 keV, a suitable nanoparticle can be selected to boost the effect of energy deposition by low energy photon beams used in brachytherapy.

19

Photochemical production of gold ﬁlms on the surface of fabric materials

Abdurazova Perizat, Sataev Malik, Kenzhibayeva Gulmira, Koshkarbayeva Shayzada, Amanbayeva Kalamkas, Raiymbekov Yerkebulan

Polish Journal of Chemical Technology

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2020

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Vol. 22, nr 4

28--30

EN

A technology for producing gold ﬁlms on the surface of fabric materials has been developed, which provides for preliminary wetting of the fabric product with aqueous solutions of gold (III) chloride. In this case, a sorption layer of gold chloride is formed on the surface of fabric materials. Then, when drying these products under sunlight, physicochemical and photochemical processes occur, leading initially to the formation of monovalent gold chlorides, which, having semiconductor properties, provide the release of elemental gold. After washing of by-products on the surface of the material remains an ultra-thin ﬁlm of gold, which has a sufﬁciently strong grip on the base. Since the proposed technology does not require special equipment it can be used to apply functional ﬁlms of gold on various products of technical, household and medical purposes.

20

Influence of different types of nanosilica on compressive strength development of cement matrix composites

Popławski J., Lelusz M.

Archives of Civil Engineering

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2020

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Vol. 66, nr 4

169--181

EN

This article presents test results of cement paste and binders with admixture of hydrophilic or hydrophobic nanosilica. The aim of the study was to determine the influence of nanosilica type and mixing method on compressive strength, porosity, and bulk density of cement paste, also on hydration heat of cement binders. The binder compounds were mixed in high speed mixer in order to provide the highest possible dispersion of nanoparticles in the binder before adding it to mixing water. Two mixing methods were studied. The admixtures increased the reactivity of cement binders. Both nanosilica types increased early compressive strength by 25% in comparison with control series. The increase in 28-day compressive strength was observed with the admixture of hydrophilic nanosilica. The differences in dynamics of binders rate of hydration and development of cement pastes compressive strength denote different reaction mechanisms of both types of nanosilica. Application of higher rotation speeds does not guarantee satisfactory mixing of the binder components. For compressive strength enhancement of cement paste prolonged mixing time occurred to be more important.

PL

Osiągnięcia nanotechnologii znalazły zastosowanie w szeregu gałęzi przemysłu. Wraz z rozwojem instrumentów naukowych stają się one również możliwe do wdrożenia w branży budowalnej, a zastosowanie nanodrobin w formie domieszek do betonu jest przykładem tego typu prób. W tym kontekście duże zainteresowanie wzbudza nanokrzemionka. Jest to materiał składający się z nanodrobin amorficznej krzemionki o dużej powierzchni właściwej i dużej czystości chemicznej. Dzięki intensywnej reakcji pucolanowej oraz zarodkowaniu reakcji hydratacji cementu sprzyja wytworzeniu zwartej struktury matrycy cementowej, co może przełożyć się na bardzo dobre parametry mechaniczne i wydłużoną trwałość kompozytu cementowego. Problemem przy stosowaniu nanodomieszek jest zapewnienie ich jednorodnego rozprowadzenia w mieszance i stwardniałym kompozycie. W celu znalezienia satysfakcjonującego rozwiązania tego problemu badane są różne rodzaje nanokrzemionki oraz różne procedury jej mieszania ze składnikami mieszanki. W artykule przedstawiono wyniki badań zaczynów i spoiw cementowych z domieszką nanokrzemionek hydrofilowej i hydrofobowej. Celem badań była ocena wpływu rodzaju nanokrzemionki oraz sposobu mieszania składników na rozwój wytrzymałości na ściskanie, porowatość kapilarną i gęstość zaczynów oraz rozwój ciepła hydratacji spoiw cementowych. Zawartość domieszek w spoiwach wynosiła 0%, 1% lub 2% masy spoiwa. Składniki spoiw cementowych zostały wymieszane w mieszarce wysokoobrotowej w celu zapewnienia możliwie jednorodnego rozprowadzenia nanodomieszek w spoiwie przed dodaniem spoiwa do wody zarobowej. Wykonano 10 serii spoiw: 5 spoiw wymieszanych I metodą mieszania (wykorzystującą dwie prędkości obrotowe mieszarki) oraz identycznych składów 5 spoiw wymieszanych II metodą mieszania (wykorzystującą jedną niższą prędkość urządzenia, ale z dłuższym etapem mieszania).