Search results for: nanoparticle functionalization

Authors: Masataka Inada, Masanao Kinoshita, Nobuaki Matsumori

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It has been demonstrated that lipid molecules in biological membranes are responsible for the functionalization and structuration of membrane proteins. However, it is still unclear how the interaction of lipid molecules with membrane proteins is correlated with the function of the membrane proteins. Here we first developed an evaluation method for the interaction between membrane proteins and lipid molecules via surface plasmon resonance (SPR) analysis. Bacteriorhodopsin (bR), which was obtained by the culture of halobacteria, was used as a membrane protein. We prepared SPR sensor chips covered with self-assembled monolayer containing mercaptocarboxylic acids, and immobilized bR onto them. Then, we evaluated the interactions with various lipids that have different structures. As a result, the halobacterium-specific glycolipid S-TGA-1 was found to have much higher affinity with bRs than other lipids. This is probably due to not only hydrophobic and electrostatic interactions but also hydrogen bonds with sugar moieties in the glycolipid. Next, we analyzed the roles of the lipid in the structuration and functionalization of bR. CD analysis showed that S-TGA-1 could promote trimerization of bR monomers more efficiently than any other lipids. Flash photolysis further indicated that bR trimers formed by S-TGA-1 reproduced the photocyclic activity of bR in purple membrane, halobacterium-membrane. These results suggest that S-TGA-1 promotes trimerization of bR through strong interactions and consequently fulfills the bR’s function efficiently.

Keywords: membrane protein, lipid, interaction, bacteriorhodopsin, glycolipid

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Authors: Worku Dejene Bekele, András Marczika Csilla Sörös

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Silver nanoparticles are silver metal with a size of 1-100nm. The most common source of silver nanoparticles is inorganic salts. Nanoparticles can be ingested through our foods and constitute nanoparticles and silver ions, whether as an additive or by migrants and, in some cases, as a pollutant. Silver nanoparticles are the most widely applicable engineered nanomaterials, especially for antimicrobial function. Ag nanoparticles give different advantages in the case of food safety, quality, and overall acceptability; however, they affect the health of humans and animals, putting them at risk of health problems and environmental pollution. Silver nanoparticles have been used widely in food packaging technologies, especially in water treatments, meat and meat products, fruit, and many other food products. This is for bio-preservation from food products. The primary goal of this review is to determine the safety and health impact of Ag nanoparticles application in food packaging and analysis of the human organs more affected by this preservative technology, to assess the implications of a nanoparticle on food safety, to determine the effects of nanoparticles on consumers health and to determine the impact of nanotechnology on product acceptability. But currently, much research has demonstrated that there is cause to believe that silver nanoparticles may have toxicological effects on biological organs and systems. The silver nanoparticles affect DNA expression, gastrointestinal barriers, lungs, and other breathing organs illness. Silver particles and molecules are very toxic. During its application in food packaging, food industries used the thinnest particle. This particle can potentially affect the gastrointestinal tracts-it suffers from mucus production, DNA, lungs, and other breezing organs. This review is targeted to demonstrate the knowledge gap that industrials use in the application of silver nanoparticles in food packaging and preservation and its health effects on the consumer.

Keywords: food preservatives, health impact, nanoparticle, silver nanoparticle

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Authors: Mehdi Ketabchi, Shamsollah Alijanlou

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The flue gas from fossil fuels combustion contains harmful pollutants dangerous for human health and the environment. One of the air pollution control methods to restrict the emission of these pollutants is based on using the nanoparticle in the adsorption process. In the present research gamma, Nano-alumina particle is added to Polyacrylonitrile (PAN) polymer through simple loading method and the adsorption capacity of the wet spun fiber is investigated. The results of exposure the fiber to the acid gasses including SO2, CO, NO2, NO and CO2 show the noticeable increase of gas adsorption capacity on fiber contains nanoparticle. The research has been conducted in Acrylic II Plant of Polyacryl Iran Corporation.

Keywords: acrylic fiber, adsorbent, wet spun, nano gamma alumina

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Authors: Waroton Paisuwan, Mongkol Sukwattanasinitt, Mamoru Tobisu, Anawat Ajavakom

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Novel dihydroquinoline derivatives (DHP and DHP-OH) were synthesized in one pot via a tandem trimerization-cyclization of methylpropiolate. DHP and DHP-OH possess strong blue fluorescence with high quantum efficiencies over 0.70 in aqueous media. DHP-OH displays a remarkable fluorescence quenching selectively to the presence of Au3+ through the oxidation of dihydropyridine to pyridinium ion as confirmed by NMR and HRMS. DHP-OH was used to demonstrate the quantitative analysis of Au3+ in water samples with the limit of detection of 33 ppb and excellent recovery (>95%). This fluorescent probe was also applied for the determination of Au3+ residue in the gold nanoparticle solution and a paper-based sensing strip for the on-site detection of Au3+.

Keywords: Gold(III) ion detection, Fluorescent sensor, Fluorescence quenching, Dihydropyridine, Gold nanoparticles (AuNPs)

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Authors: Mohamed Eldessouki, Ebraheem Shady, Yasser Gowayed

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Carbon nanotubes (CNTs) are known for having high elastic properties with high surface area that promote them as good candidates for reinforcing polymeric matrices. In composite materials, CNTs lack chemical bonding with the surrounding matrix which decreases the possibility of better stress transfer between the components. In this work, a chemical treatment for activating the surface of the multi-wall carbon nanotubes (MWCNT) was applied and the effect of this functionalization on the elastic properties of the epoxy nanocomposites was studied. Functional amino-groups were added to the surface of the CNTs and it was evaluated to be about 34% of the total weight of the CNTs. Elastic modulus was found to increase by about 40% of the neat epoxy resin at CNTs’ weight fraction of 0.5%. The elastic modulus was found to decrease after reaching a certain concentration of CNTs which was found to be 1% wt. The scanning electron microscopic pictures showed the effect of the CNTs on the crack propagation through the sample by forming stress concentrated spots at the nanocomposite samples.

Keywords: carbon nanotubes functionalization, crack propagation, elastic modulus, epoxy nanocomposites

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Authors: Ismaila H. Zarma, Mahmoud Ahmed, Shinichi Ookawara, Hamdi Abo-Ali

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Phase change materials (PCM) are an ideal thermal storage medium. They are characterized by a high latent heat, which allows them to store large amounts of energy when the material transitions into different physical states. Concentrated photovoltaic (CPV) systems are widely recognized as the most efficient form of Photovoltaic (PV) for thermal energy which can be stored in Phase Change Materials (PCM). However, PCMs often have a low thermal conductivity which leads to a slow transient response. This makes it difficult to quickly store and access the energy stored within the PCM based systems, so there is need to improve transient responses and increase the thermal conductivity. The present study aims to investigate and analyze the melting and solidification process of phase change materials (PCMs) enhanced by nanoparticle contained in a container. Heat flux from concentrated photovoltaic is applied in an attempt to analyze the thermal performance and the impact of nanoparticles. The work will be realized by using a two dimensional model which take into account the phase change phenomena based on the principle of enthalpy method. Numerical simulations have been performed to investigate heat and flow characteristics by using governing equations, to ascertain the impacts of the nanoparticle loading. The Rayleigh number, sub-cooling as well as the unsteady evolution of the melting front and the velocity and temperature fields were also observed. The predicted results exhibited a good agreement, showing thermal enhancement due to present of nanoparticle which leads to decreasing the melting time.

Keywords: thermal energy storage, phase-change material, nanoparticle, concentrated photovoltaic

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Authors: Supriya, J. K. Basu, S. Sengupta

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Silver nanoparticles have caught a lot of attention because of its unique physical and chemical properties. Silver nanoparticles embedded in polyvinyl alcohol (PVA/Ag) free-standing film have been prepared by microwave irradiation in few minutes. PVA performed as a reducing agent, stabilizing agents as well as support for silver nanoparticles. UV-Vis spectrometry, scanning transmission electron (SEM) and transmission electron microscopy (TEM) techniques affirmed the reduction of silver ion to silver nanoparticles in the polymer matrix. Effect of irradiation time, the concentration of PVA and concentration of silver precursor on the synthesis of silver nanoparticle has been studied. Particles size of silver nanoparticles decreases with increase in irradiation time. Concentration of silver nanoparticles increases with increase in concentration of silver precursor. Good dispersion of silver nanoparticles in the film has been confirmed by TEM analysis. Particle size of silver nanoparticle has been found to be in the range of 2-10nm. Catalytic property of prepared silver nanoparticles as a heterogeneous catalyst has been studied in the reduction of p-Nitrophenol (a water pollutant) with >98% conversion. From the experimental results, it can be concluded that PVA encapsulated Ag nanoparticles film as a catalyst shows better efficiency and reusability in the reduction of p-Nitrophenol.

Keywords: biopolymer, microwave irradiation, silver nanoparticles, water pollutant

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Authors: Mehdi Ketabchi, Shallah Alijanlo

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The flue gas from fossil fuels combustion contains harmful pollutants dangerous for human health and environment. One of the air pollution control methods to restrict the emission of these pollutants is based on using the nanoparticle in adsorption process. In the present research, gamma nano-alumina particle is added to polyacrylonitrile (PAN) polymer through simple loading method, and the adsorption capacity of the wet spun fiber is investigated. The results of exposure the fiber to the acid gases including SO₂, CO, NO₂, NO, and CO₂ show the noticeable increase of gas adsorption capacity on fiber contains nanoparticle. The research has been conducted in Acrylic II Plant of Polyacryl Iran Corporation.

Keywords: acrylic fiber, adsorbent, wet spun, polyacryl company, nano gamma alumina

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Authors: Khachatur V. Nerkararyan, Sergey I. Bozhevolnyi

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We investigate relaxation dynamics of a quantum dipole emitter (QDE), e.g., a molecule or quantum dot, located near a metal nanoparticle (MNP) exhibiting a dipolar localized surface plasmon (LSP) resonance at the frequency of the QDE radiative transition. It is shown that under the condition of the QDE-MNP characteristic relaxation time being much shorter than that of the QDE in free-space but much longer than the LSP lifetime. It is also shown that energy dissipation in the QDE-MNP system is relatively weak with the probability of the photon emission being about 0.75, a number which, rather surprisingly, does not explicitly depend on the metal absorption characteristics. The degree of entanglement measured by the concurrency takes the maximum value, while the distances between the QDEs and metal ball approximately are equal.

Keywords: metal nanoparticle, localized surface plasmon, quantum dipole emitter, relaxation dynamics

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Authors: Brindusa Balanuca, Raluca Stan, Cristina Ott, Matei Raicopol

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The current study aims to develop anti corrosive coatings using vegetable oil (VO)-based polymers. Due to their chemical versatility, reduced costs and more important, higher hydrophobicity, VO’s are great candidates in the field of anti-corrosive materials. Lignin (Ln) derivatives were also used in this research study in order to achieve performant hydrophobic anti-corrosion layers. Methods Through a rational functionalization pathway, the selected VO (linseed oil) is converted to more reactive monomer – methacrylate linseed oil (noted MLO). The synthesized MLO cover the metals surface in a thin layer and through different polymerization techniques (using visible radiation or temperature, respectively) and well-established reaction conditions, is converted to a hydrophobic coating capable to protect the metals against corrosive factors. In order to increase the anti-corrosion protection, lignin (Ln) was selected to be used together with MLO macromonomer. Thus, super hydrophobic protective coatings will be formulated. Results The selected synthetic strategy to convert the VO in more reactive compounds – MLO – has led to a functionalization degree of greater than 80%. The obtained monomers were characterized through NMR and FT-IR by monitoring the characteristic signals after each synthesis step. Using H-NMR data, the functionalization degrees were established. VO-based and also VO-Ln anti corrosion formulations were both photochemical and thermal polymerized in specific reaction conditions (initiators, temperature range, reaction time) and were tested as anticorrosive coatings. Complete and advances characterization of the synthesized materials will be presented in terms of thermal, mechanical and morphological properties. The anticorrosive properties were also evaluated and will be presented. Conclusions Through the design strategy briefly presented, new composite materials for metal corrosion protection were successfully developed, using natural derivatives: vegetable oils and lignin, respectively.

Keywords: anticorrosion protection, hydrophobe layers, lignin, methacrylates, vegetable oil

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Authors: Yaxin Tang, Mingao Hou, Qian He, Guangfu Luo

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Bimetallic nanoparticles serve as a promising class of catalysts with tunable properties suitable for diverse catalytic reactions, yet a comprehensive understanding of their actual structures under operating conditions and the optimal design principles remains largely elusive. In this study, we unveil a prevalent surface segregation phenomenon in nearly 100 platinum-group-element-based bimetallic nanoparticles through first principles-based molecular dynamics simulations. Our findings highlight that two components in a nanoparticle with relatively lower surface energy tend to segregate to the surface. Motivated by this discovery, we propose a deliberate exploitation of surface segregation in designing bimetallic nanoparticle catalysts, aiming for heightened stability and reduced consumption of precious metals. To validate this strategy, we further investigate 36 platinum-based bimetallic nanoparticles for propane dehydrogenation catalysis. Through a systematic examination of catalytic sites on nanoparticles, we identify several systems as top candidates with Pt-enriched surfaces, remarkable thermal stability, and superior catalytic activity for propane dehydrogenation. The insights gained garnered from this study are anticipated to provide a valuable framework for the optimal design of other bimetallic nanoparticles.

Keywords: bimetallic nanoparticles, platinum-group element, catalysis, surface segregation, first-principles calculations

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Authors: Camille Perréard, Yoann Ladner, Fanny D'Orlyé, Stéphanie Descroix, Vélan Taniga, Anne Varenne, Cédric Guyon, Michael. Tatoulian, Frédéric Kanoufi, Cyrine Slim, Sophie Griveau, Fethi Bedioui

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The development of micro total analysis systems is of major interest for contaminant and biomarker analysis. As a lab-on-chip integrates all steps of an analysis procedure in a single device, analysis can be performed in an automated format with reduced time and cost, while maintaining performances comparable to those of conventional chromatographic systems. Moreover, these miniaturized systems are either compatible with field work or glovebox manipulations. This work is aimed at developing an analytical microsystem for trace and ultra trace quantitation in complex matrices. The strategy consists in the integration of a sample pretreatment step within the lab-on-chip by a confinement zone where selective ligands are immobilized for target extraction and preconcentration. Aptamers were chosen as selective ligands, because of their high affinity for all types of targets (from small ions to viruses and cells) and their ease of synthesis and functionalization. This integrated target extraction and concentration step will be followed in the microdevice by an electrokinetic separation step and an on-line detection. Polymers consisting of cyclic olefin copolymer (COC) or fluoropolymer (Dyneon THV) were selected as they are easy to mold, transparent in UV-visible and have high resistance towards solvents and extreme pH conditions. However, because of their low chemical reactivity, surface treatments are necessary. For the design of this miniaturized diagnostics, we aimed at modifying the microfluidic system at two scales : (1) on the entire surface of the microsystem to control the surface hydrophobicity (so as to avoid any sample wall adsorption) and the fluid flows during electrokinetic separation, or (2) locally so as to immobilize selective ligands (aptamers) on restricted areas for target extraction and preconcentration. We developed different novel strategies for the surface functionalization of COC and Dyneon, based on plasma, chemical and /or electrochemical approaches. In a first approach, a plasma-induced immobilization of brominated derivatives was performed on the entire surface. Further substitution of the bromine by an azide functional group led to covalent immobilization of ligands through “click” chemistry reaction between azides and terminal alkynes. COC and Dyneon materials were characterized at each step of the surface functionalization procedure by various complementary techniques to evaluate the quality and homogeneity of the functionalization (contact angle, XPS, ATR). With the objective of local (micrometric scale) aptamer immobilization, we developed an original electrochemical strategy on engraved Dyneon THV microchannel. Through local electrochemical carbonization followed by adsorption of azide-bearing diazonium moieties and covalent linkage of alkyne-bearing aptamers through click chemistry reaction, typical dimensions of immobilization zones reached the 50 µm range. Other functionalization strategies, such as sol-gel encapsulation of aptamers, are currently investigated and may also be suitable for the development of the analytical microdevice. The development of these functionalization strategies is the first crucial step in the design of the entire microdevice. These strategies allow the grafting of a large number of molecules for the development of new analytical tools in various domains like environment or healthcare.

Keywords: alkyne-azide click chemistry (CuAAC), electrochemical modification, microsystem, plasma bromination, surface functionalization, thermoplastic polymers

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Authors: El-Said I. El-Shafey, Syeda Naheed F. Ali, Saleh S. Al-Busafi, Haider A. J. Al-Lawati

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Date palm leaflets were utilized as a precursor for activated carbon (AC) preparation using KOH activation. AC produced was oxidized using nitric acid producing oxidized activated carbon (OAC). OAC that possesses acidic surface was surface functionalized to produce basic activated carbons using linear diamine compounds (ethylene diamine and propylene diamine). OAC was also functionalized to produce hydrophobic activated carbons using ethylamine (EA) and aniline (AN). Dehydrated carbon was also prepared from date palm leaflets using sulfuric acid dehydration/ oxidation and was surface functionalized in the same way as AC. Nitric acid oxidation was not necessary for DC as it is acidic carbon. The surface area of AC is high (823 m2/g) with microporosity domination, however, after oxidation and surface functionalization, both the surface area and surface microporosity decrease tremendously. DC surface area was low (15 m2/g) with mesoporosity domination. Surface functionalization has decreased the surface area of activated carbons. FTIR spectra show that -COOH group on DC and OAC almost disappeared after surface functionalization. The surface chemistry of all carbons produced was tested for pHzpc, basic sites, boehm titration, thermogravimetric analysis and zeta potential measurement. Scanning electron microscopy and energy dispersive spectroscopy in addition to CHN elemental analysis were also carried out. DC and OAC possess low pHzpc and high surface functionality, however, basic and hydrophobic carbons possess high pHzpc and low surface functionality. The different behavior of carbons is related to their different surface chemistry. Methylene blue adsorption was found to be faster on hydrophobic carbons based on AC and DC. The Larger adsorption capacity of methylene blue was found for hydrophobic carbons. Dominating adsorption forces of methylene blue varies from carbon to another depending on its surface nature. Sorption forces include hydrophobic forces, H-bonding, electrostatic interactions and van der Waals forces.

Keywords: carbon, acidic, basic, hydrophobic

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Authors: Min Han, Di Wu, Lin Yuan, Fei Liu

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Mechanical sensors have undergone a continuous evolution and have become an important part of many industries, ranging from manufacturing to process, chemicals, machinery, health-care, environmental monitoring, automotive, avionics, and household appliances. Concurrently, the microelectronics and microfabrication technology have provided us with the means of producing mechanical microsensors characterized by high sensitivity, small size, integrated electronics, on board calibration, and low cost. Here we report a new kind of mechanical sensors based on the quantum transport process of electrons in the closely spaced nanoparticle films covering a flexible polymer sheet. The nanoparticle films were fabricated by gas phase depositing of preformed metal nanoparticles with a controlled coverage on the electrodes. To amplify the conductance of the nanoparticle array, we fabricated silver interdigital electrodes on polyethylene terephthalate(PET) by mask evaporation deposition. The gaps of the electrodes ranged from 3 to 30μm. Metal nanoparticles were generated from a magnetron plasma gas aggregation cluster source and deposited on the interdigital electrodes. Closely spaced nanoparticle arrays with different coverage could be gained through real-time monitoring the conductance. In the film coulomb blockade and quantum, tunneling/hopping dominate the electronic conduction mechanism. The basic principle of the mechanical sensors relies on the mechanical deformation of the fabricated devices which are translated into electrical signals. Several kinds of sensing devices have been explored. As a strain sensor, the device showed a high sensitivity as well as a very wide dynamic range. A gauge factor as large as 100 or more was demonstrated, which can be at least one order of magnitude higher than that of the conventional metal foil gauges or even better than that of the semiconductor-based gauges with a workable maximum applied strain beyond 3%. And the strain sensors have a workable maximum applied strain larger than 3%. They provide the potential to be a new generation of strain sensors with performance superior to that of the currently existing strain sensors including metallic strain gauges and semiconductor strain gauges. When integrated into a pressure gauge, the devices demonstrated the ability to measure tiny pressure change as small as 20Pa near the atmospheric pressure. Quantitative vibration measurements were realized on a free-standing cantilever structure fabricated with closely-spaced nanoparticle array sensing element. What is more, the mechanical sensor elements can be easily scaled down, which is feasible for MEMS and NEMS applications.

Keywords: gas phase deposition, mechanical sensors, metallic nanoparticle arrays, quantum conductance

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Authors: Hamza Simsir, Nurettin Eltugral, Selhan Karagöz

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Surface modification and functionalization has been an important tool for scientists in order to open new frontiers in nano science and nanotechnology. Desired surface characteristics for the intended applications can be achieved with surface functionalization. In this work, the effect of water soluble ligands on the adsorption capabilities of silver nanoparticles onto AC which was synthesized from German beech wood, was investigated. Sodium borohydride (NaBH4) and polyvinyl alcohol (PVA) were used as the ligands. Silver nanoparticles with different surface coatings have average sizes range from 10 to 13 nm. They were synthesized in aqueous media by reducing Ag (I) ion in the presence of ligands. These particles displayed adsorption tendencies towards AC when they were mixed together and shaken in distilled water. Silver nanoparticles (NaBH4-AgNPs) reduced and stabilized by NaBH4 adsorbed onto AC with a homogenous dispersion of aggregates with sizes in the range of 100-400 nm. Beside, silver nanoparticles, which were prepared in the presence of both NaBH4 and PVA (NaBH4/PVA-Ag NPs), demonstrated that NaBH4/PVA-Ag NPs adsorbed and dispersed homogenously but, they aggregated with larger sizes on the AC surface (range from 300 to 600 nm). In addition, desorption resistance of Ag nanoparticles were investigated in distilled water. According to the results AgNPs were not desorbed on the AC surface in distilled water.

Keywords: Silver nanoparticles, ligand, activated carbon, adsorption

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Authors: Anna Kolanowska, Anna Kuziel, Sławomir Boncel

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Carbon nanotubes (CNTs) represent a combination of lightness and nanoscopic size with high tensile strength, excellent thermal and electrical conductivity. By now, CNTs have been used as a support in heterogeneous catalysis (CuCl anchored to pre-functionalized CNTs) in the Ullmann-type coupling with aryl halides toward formation of C-N and C-O bonds. The results indicated that the stability of the catalyst was much improved and the elaborated catalytic system was efficient and recyclable. However, CNTs have not been considered as the substrate itself in the Ullmann-type reactions. But if successful, this functionalization would open new areas of CNT chemistry leading to enhanced in-solvent/matrix nanotube individualization. The copper-catalyzed Ullmann-type reaction is an attractive method for the formation of carbon-heteroatom and carbon-carbon bonds in organic synthesis. This condensation reaction is usually conducted at temperature as high as 200 oC, often in the presence of stoichiometric amounts of copper reagent and with activated aryl halides. However, a small amount of organic additive (e.g. diamines, amino acids, diols, 1,10-phenanthroline) can be applied in order to increase the solubility and stability of copper catalyst, and at the same time to allow performing the reaction under mild conditions. The copper (pre-)catalyst is prepared by in situ mixing of copper salt and the appropriate chelator. Our research is focused on the application of Ullmann-type reaction for the covalent functionalization of CNTs. Firstly, CNTs were chlorinated by using iodine trichloride (ICl3) in carbon tetrachloride (CCl4). This method involves formation of several chemical species (ICl, Cl2 and I2Cl6), but the most reactive is the dimer. The fact (that the dimer is the main individual in CCl4) is the reason for high reactivity and possibly high functionalization levels of CNTs. This method, indeed, yielded a notable amount of chlorine onto the MWCNT surface. The next step was the reaction of CNT-Cl with three substrates: aniline, iodobenzene and phenol for the formation C-N, C-C and C-O bonds, respectively, in the presence of 1,10-phenanthroline and cesium carbonate (Cs2CO3) as a base. As the CNT substrates, two multi-wall CNT (MWCNT) types were used: commercially available Nanocyl NC7000™ (9.6 nm diameter, 1.5 µm length, 90% purity) and thicker MWCNTs (in-house) synthesized in our laboratory using catalytic chemical vapour deposition (c-CVD). In-house CNTs had diameter ranging between 60-70 nm and length up to 300 µm. Since classical Ullmann reaction was found as suffering from poor yields, we have investigated the effect of various solvents (toluene, acetonitrile, dimethyl sulfoxide and N,N-dimethylformamide) on the coupling of substrates. Owing to the fact that the aryl halides show the reactivity order of I>Br>Cl>F, we have also investigated the effect of iodine presence on CNT surface on reaction yield. In this case, in first step we have used iodine monochloride instead of iodine trichloride. Finally, we have used the optimized reaction conditions with p-bromophenol and 1,2,4-trihydroxybenzene for the control of CNT dispersion.

Keywords: carbon nanotubes, coupling reaction, functionalization, Ullmann reaction

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Authors: Marziyeh Heydari, Hossein Shokouhmand

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This article presents a numerical study of natural convection of a heat source embedded on the up wall of an enclosure filled with nanofluid. The bottom and vertical walls of the enclosure are maintained at a relatively low temperature. The type of nanofluid and solid volume fraction of nanoparticle on the heat transfer performance is studied. The results indicated that adding nanoparticle into pure paraffin improves heat transfer. The results are presented over a wide range of Rayleigh numbers(Ra=〖10〗^3 〖-10〗^5), the volume fraction of nanoparticles (0≤ɸ≤0.4%). For an enclosure, the Nusselt number of a cu-paraffin nanofluid was reduced by increasing the volume fraction of nanoparticles above 0.2%.

Keywords: nanofluid, heat transfer, heat source, enclosure

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Authors: Lucija Pustahija, Christine Bandl, Wolfgang Kern, Christian Mitterer

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Concerning today´s ecological demands, producing reliable materials from sustainable resources is a continuously developing topic. Such an example is the production of carbon materials via pyrolysis of natural gases or biomass. The amazing properties of pyrolytic carbon are utilized in various fields, where in particular the application in building industry is a promising way towards the utilization of pyrolytic carbon and composites based on pyrolytic carbon. For many applications, surface modification of carbon is an important step in tailoring its properties. Therefore, in this paper, an investigation of different oxidation methods was performed to prepare the carbon surface before functionalizing it with organosilanes, which act as coupling agents for epoxy and polyurethane resins. Made in such a way, a building material based on carbon composites could be used as a lightweight, durable material that can be applied where water or air filtration / purification is needed. In this work, both wet and dry oxidation were investigated. Wet oxidation was first performed in solutions of nitric acid (at 120 °C and 150 °C) followed by oxidation in hydrogen peroxide (80 °C) for 3 and 6 h. Moreover, a hydrothermal method (under oxygen gas) in autoclaves was investigated. Dry oxidation was performed under plasma and corona discharges, using different power values to elaborate optimum conditions. Selected samples were then (in preliminary experiments) subjected to a silanization of the surface with amino and glycidoxy organosilanes. The functionalized surfaces were examined by X-ray photon spectroscopy and Fourier transform infrared spectroscopy spectroscopy, and by scanning electron microscopy. The results of wet and dry oxidation methods indicated that the creation of functionalities was influenced by temperature, the concentration of the reagents (and gases) and the duration of the treatment. Sequential oxidation in aq. HNO₃ and H₂O₂ results in a higher content of oxygen functionalities at lower concentrations of oxidizing agents, when compared to oxidizing the carbon with concentrated nitric acid. Plasma oxidation results in non-permanent functionalization on the carbon surface, by which it´s necessary to find adequate parameters of oxidation treatments that could enable longer stability of functionalities. Results of the functionalization of the carbon surfaces with organosilanes will be presented as well.

Keywords: building materials, dry oxidation, organosilanes, pyrolytic carbon, resins, surface functionalization, wet oxidation

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Authors: Tesfay Gebremicheal Reda, K. Samatha, Paul Douglas Sanasi, D. Parajuli

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Nanoparticle technology is fast progressing and is being employed in innumerable medical applications. At this time, the public's health is seriously threatened by the rise of bacterial strains resistant to several medications. Metal nanoparticles are a potential alternate approach for tackling this global concern, and this is the main focus of this study. The citrate precursor sol-gel synthesis method was used to synthesize the Niₓ Co₁₋ₓ Fe₂ O₄, (where x = 0.0:0.2:1.0) nanoparticle. XRD identified the development of the cubic crystal structure to have a preferential orientation along (311), and the average particle size was found to be 29-38 nm. The average crystallizes assessed with ImageJ software and origin 22 of the SEM are nearly identical to the XRD results. In the created NCF NPs, the FT-IR spectroscopy reveals structural examinations and the redistribution of cations between octahedral (505-428 cm⁻¹) and tetrahedral (653-603 cm⁻¹) locales. As the Co²⁺ cation is substituted with Ni²⁺, the coercive fields HC decrease from 2384 Oe to 241.93 Oe. Band gap energy rises as Ni concentration increases, which may be attributed to the fact that the ionic radii of Ni²⁺ ions are smaller than that of Co²⁺ ions, which results in a strong electrostatic interaction. On the contrary, except at x = 0.4, the dielectric constant decreases as the nickel concentration increases. According to the findings of this research work, nanoparticles are composed of Ni₀.₄ Co₀.₆ Fe₂ O₄ have demonstrated a promising value against S. aureus and E. coli, and it suggests a proposed model for their potential use as a source of antibacterial agent.

Keywords: antimicrobial, band gap, citrate precursor, dielectric, nanoparticle

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Authors: Sourav Ghosh, Antony Gomes

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Since 1894 anti-snake venom serum (ASVS) is the only available treatment against snake envenomation, although there are many side effects and limitations. The need for a supportive treatment was felt for a long time to overcome the side effects and limitations of ASVS. Andrographolide conjugated with gold nanoparticle (A-GNP) has been found to antagonize viper venom-induced local damages. The present study was aimed to study the protective efficacy of A-GNP against Viper venom-induced inflammatory response and organ toxicity in animal model. Ethical clearance was obtained from animal experiments. Physico-chemical characterization of A-GNP was done by DLS (diameter and zeta potential), FE-SEM and XRD. Swiss albino male mice were divided into 4 groups: Gr.1-Sham control, Gr.2- Russell’s Viper venom (RVV) control, Gr.3- andrographolide treated and Gr.4- A-GNP treated. The 1/5th minimum lethal dose of RVV (500µg/kg, s.c.) was induced in animals of group 2, 3 & 4 animals, followed by treatment with andrographolide (100mg/kg, i.p.) and A-GNP (100mg/kg, i.v.) in group 3 & 4 animals, respectively. Blood was collected after 18 h, serum was prepared, and inflammatory markers (IL 1β, 6, 17a, 10, TNF α) and biochemical markers (AST, ACP, LDH, urea, creatinine) were assessed. Values were expressed as mean±SEM (n=4), one way ANOVA was done, P<0.05 was considered as statistically significant. DLS size showed the hydrodynamic diameter of A-GNP to be 230-260nm with polydispersity index of 0.103 and zeta potential was -18.32mV. XRD data confirmed the presence of crystalline gold in A-GNP, and FESEM indicated the presence of nearly spherical particle with size18-24nm.Treatment with A-GNP significantly decreased viper venom-induced proinflammatory markers (IL 1β, 6, 17, TNF α) increased anti-inflammatory markers (IL 10) and decreased organ toxicity markers (AST, ACP, LDH, urea, creatinine) in animal model. Venom neutralization efficacy of A-GNP was > andrographolide, which confirmed the increased efficacy of andrographolide after gold nanoparticle conjugation. Venom neutralization by A-GNP was due to anti-oxidant/anti-inflammatory activity of andrographolide, which showed increased efficacy after gold nanoparticle tagging. Thus, A-GNP may serve as a supportive therapy in snake-bite (against inflammatory response and organ toxicity) subject to further detail studies.

Keywords: andrographolide, gold nanoparticle, inflammatory response, organ toxicity, snake venom, snake venom neutralization, viper venom

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Authors: Shiva Shakori Poshteh

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Lung cancer is a highly prevalent and devastating disease, representing a significant global health concern with profound implications for healthcare systems and society. Its high incidence, mortality rates, and late-stage diagnosis contribute to its formidable nature. To address these challenges, nanoparticle-based drug delivery has emerged as a promising therapeutic strategy. Curcumin (CUR), a natural compound derived from turmeric, has garnered attention as a potential nanomedicine for lung cancer treatment. Nanoparticle formulations of CUR offer several advantages, including improved drug delivery efficiency, enhanced stability, controlled release kinetics, and targeted delivery to lung cancer cells. CUR exhibits a diverse array of effects on cancer cells. It induces apoptosis by upregulating pro-apoptotic proteins, such as Bax and Bak, and downregulating anti-apoptotic proteins, such as Bcl-2. Additionally, CUR inhibits cell proliferation by modulating key signaling pathways involved in cancer progression. It suppresses the PI3K/Akt pathway, crucial for cell survival and growth, and attenuates the mTOR pathway, which regulates protein synthesis and cell proliferation. CUR also interferes with the MAPK pathway, which controls cell proliferation and survival, and modulates the Wnt/β-catenin pathway, which plays a role in cell proliferation and tumor development. Moreover, CUR exhibits potent antioxidant activity, reducing oxidative stress and protecting cells from DNA damage. Utilizing CUR as a standalone treatment is limited by poor bioavailability, lack of targeting, and degradation susceptibility. Nanoparticle-based delivery systems can overcome these challenges. They enhance CUR’s bioavailability, protect it from degradation, and improve absorption. Further, Nanoparticles enable targeted delivery to lung cancer cells through surface modifications or ligand-based targeting, ensuring sustained release of CUR to prolong therapeutic effects, reduce administration frequency, and facilitate penetration through the tumor microenvironment, thereby enhancing CUR’s access to cancer cells. Thus, nanoparticle-based CUR delivery systems promise to improve lung cancer treatment outcomes. This article provides an overview of lung cancer, explores CUR nanoparticles as a treatment approach, discusses the benefits and challenges of nanoparticle-based drug delivery, and highlights prospects for CUR nanoparticles in lung cancer treatment. Future research aims to optimize these delivery systems for improved efficacy and patient prognosis in lung cancer.

Keywords: lung cancer, curcumin, nanomedicine, nanoparticle-based drug delivery

Procedia PDF Downloads 43

Authors: Feixiong Chen, Naoufel Haddour, Marie Frenea-Robin, Yves MéRieux, Yann Chevolot, Virginie Monnier

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Neonatal thrombopenia occurs when the mother generates antibodies against her baby’s platelet antigens. It is particularly critical for newborns because it can cause coagulation troubles leading to intracranial hemorrhage. In this case, diagnosis must be done quickly to make platelets transfusion immediately after birth. Before transfusion, platelet antigens must be tested carefully to avoid rejection. The majority of thrombopenia (95 %) are caused by antibodies directed against Human Platelet Antigen 1a (HPA-1a) or 5b (HPA-5b). The common method for antigen platelets detection is polymerase chain reaction allowing for identification of gene sequence. However, it is expensive, time-consuming and requires significant blood volume which is not suitable for newborns. We propose to develop a point-of-care device based on double functionalized magnetic colloids with 1) antibodies specific to antigen platelets and 2) highly sensitive electroactive molecules in order to be detected by an electrochemical microsensor. These magnetic colloids will be used first to isolate platelets from other blood components, then to capture specifically platelets bearing HPA-1a and HPA-5b antigens and finally to attract them close to sensor working electrode for improved electrochemical signal. The expected advantages are an assay time lower than 20 min starting from blood volume smaller than 100 µL. Our functionalization procedure based on amine dendrimers and NHS-ester modification of initial carboxyl colloids will be presented. Functionalization efficiency was evaluated by colorimetric titration of surface chemical groups, zeta potential measurements, infrared spectroscopy, fluorescence scanning and cyclic voltammetry. Our results showed that electroactive molecules and antibodies can be immobilized successfully onto magnetic colloids. Application of a magnetic field onto working electrode increased the detected electrochemical signal. Magnetic colloids were able to capture specific purified antigens extracted from platelets.

Keywords: Magnetic Nanoparticles , Electroactive Molecules, Antibody, Platelet

Procedia PDF Downloads 239

Authors: Srinivasa Reddy Mallampati, Min Hee Park, Soo Mim Cho, Sung Hyeon Yoon

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One of the issues of End of Life Vehicles (ELVs) recycling promotion is technology for the appropriate treatment of automotive shredder residue (ASR). Owing to its high heterogeneity and variable composition (plastic (23–41%), rubber/elastomers (9–21%), metals (6–13%), glass (10–20%) and dust (soil/sand) etc.), ASR can be classified as ‘hazardous waste’, on the basis of the presence of heavy metals (HMs), PCBs, BFRs, mineral oils, etc. Considering their relevant concentrations, these metals and plastics should be properly recovered for recycling purposes before ASR residues are disposed of. Brominated flame retardant additives in ABS/HIPS and PVC may generate dioxins and furans at elevated temperatures. Moreover, these BFRs additives present in plastic materials may leach into the environment during landfilling operations. ASR thermal process removes some of the organic material but concentrates, the heavy metals and POPs present in the ASR residues. In the present study, Fe/Ca/CaO nanoparticle assisted ozone treatment has been found to selectively hydrophilize the surface of ABS/HIPS and PVC plastics, enhancing its wettability and thereby promoting its separation from ASR plastics by means of froth flotation. The water contact angles, of ABS/HIPS and PVC decreased, about 18.7°, 18.3°, and 17.9° in ASR respectively. Under froth flotation conditions at 50 rpm, about 99.5% and 99.5% of HIPS in ASR samples sank, resulting in a purity of 98% and 99%. Furthermore, at 150 rpm a 100% PVC separation in the settled fraction, with 98% of purity in ASR, respectively. Total recovery of non-ABS/HIPS and PVC plastics reached nearly 100% in the floating fraction. This process improved the quality of recycled ASR plastics by removing surface contaminants or impurities. Further, a hybrid ball-milling and with Fe/Ca/CaO nanoparticle froth flotation process was established for the recovery of HMs from ASR. After ball-milling with Fe/Ca/CaO nanoparticle additives, the flotation efficiency increased to about 55 wt% and the HMs recovery were also increased about 90% for the 0.25 mm size fractions of ASR. Coating with Fe/Ca/CaO nanoparticles associated with subsequent microbubble froth flotation allowed the air bubbles to attach firmly on the HMs. SEM–EDS maps showed that the amounts of HMs were significant on the surface of the floating ASR fraction. This result, along with the low HM concentration in the settled fraction, was confirmed by elemental spectra and semi-quantitative SEM–EDS analysis. Developed hybrid preferential hazardous plastics and metals separation process from ASR is a simple, highly efficient, and sustainable procedure.

Keywords: end of life vehicles shredder residue, hazardous plastics, nanoparticle froth flotation, separation process

Procedia PDF Downloads 255

Authors: Lukasz Szymanski, Zbigniew Kolacinski, Grzegorz Raniszewski, Slawomir Wiak, Lukasz Pietrzak, Dariusz Koza, Karolina Przybylowska-Sygut, Ireneusz Majsterek, Zbigniew Kaminski, Justyna Fraczyk, Malgorzata Walczak, Beata Kolasinska, Adam Bednarek, Joanna Konka

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The aim of this work is to investigate the influence of electromagnetic field from the range of radio frequencies on the desired nanoparticles for cancer therapy. In the article, the development and demonstration of the method and the model device for hyperthermic selective destruction of cancer cells are presented. This method was based on the synthesis and functionalization of carbon nanotubes serving as ferromagnetic material nanocontainers. The methodology of the production carbon - ferromagnetic nanocontainers (FNCs) includes: The synthesis of carbon nanotubes, chemical, and physical characterization, increasing the content of a ferromagnetic material and biochemical functionalization involving the attachment of the key addresses. The ferromagnetic nanocontainers were synthesised in CVD and microwave plasma system. Biochemical functionalization of ferromagnetic nanocontainers is necessary in order to increase the binding selectively with receptors presented on the surface of tumour cells. Multi-step modification procedure was finally used to attach folic acid on the surface of ferromagnetic nanocontainers. Pristine ferromagnetic carbon nanotubes are not suitable for application in medicine and biotechnology. Appropriate functionalization of ferromagnetic carbon nanotubes allows to receiving materials useful in medicine. Finally, a product contains folic acids on the surface of FNCs. The folic acid is a ligand of folate receptors – α which is overexpressed on the surface of epithelial tumours cells. It is expected that folic acids will be recognized and selectively bound by receptors presented on the surface of tumour cells. In our research, FNCs were covalently functionalized in a multi-step procedure. Ferromagnetic carbon nanotubes were oxidated using different oxidative agents. For this purpose, strong acids such as HNO3, or mixture HNO3 and H2SO4 were used. Reactive carbonyl and carboxyl groups were formed on the open sides and at the defects on the sidewalls of FNCs. These groups allow further modification of FNCs as a reaction of amidation, reaction of introduction appropriate linkers which separate solid surface of FNCs and ligand (folic acid). In our studies, amino acid and peptide have been applied as ligands. The last step of chemical modification was reaction-condensation with folic acid. In all reaction as coupling reagents were used derivatives of 1,3,5-triazine. The first trials in the device for hyperthermal RF generator have been done. The frequency of RF generator was in the ranges from 10 to 14Mhz and from 265 to 621kHz. Obtained functionalized nanoparticles enabled to reach the temperature of denaturation tumor cells in given frequencies.

Keywords: cancer colon cells, carbon nanotubes, hyperthermia, ligands

Procedia PDF Downloads 287

Authors: H. Bayat, M. Majidi, M. Bolhasani, A. Karbalaie Alilou, A. Mirabdolah Lavasani

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Unsteady flow and heat transfer from a circular cylinder in cross-flow is studied numerically. The governing equations are solved by using finite volume method. Reynolds number varies in range of 50 to 200, in this range flow is considered to be laminar and unsteady. Al2O3 nanoparticle with volume fraction in range of 5% to 20% is added to pure water. Effects of adding nanoparticle to pure water on lift and drag coefficient and Nusselt number is presented. Addition of Al2O3 has inconsiderable effect on the value of drags and lift coefficient. However, it has significant effect on heat transfer; results show that heat transfer of Al2O3 nanofluid is about 9% to 36% higher than pure water.

Keywords: nanofluid, heat transfer, unsteady flow, forced convection, cross-flow

Procedia PDF Downloads 364

Authors: Vladimir A. Basiuk, Laura J. Flores-Sanchez, Victor Meza-Laguna, Jose O. Flores-Flores, Lauro Bucio-Galindo, Elena V. Basiuk

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Noncovalent nanohybrid materials combining carbon nanotubes (CNTs) with phthalocyanines (Pcs) is a subject of increasing research effort, with a particular emphasis on the design of new heterogeneous catalysts, efficient organic photovoltaic cells, lithium batteries, gas sensors, field effect transistors, among other possible applications. The possibility of using unsubstituted Pcs for CNT functionalization is very attractive due to their very moderate cost and easy commercial availability. However, unfortunately, the deposition of unsubstituted Pcs onto nanotube sidewalls through the traditional liquid-phase protocols turns to be very problematic due to extremely poor solubility of Pcs. On the other hand, unsubstituted free-base H₂Pc phthalocyanine ligand, as well as many of its transition metal complexes, exhibit very high thermal stability and considerable volatility under reduced pressure, which opens the possibility for their physical vapor deposition onto solid surfaces, including nanotube sidewalls. In the present work, we show the possibility of simple, fast and efficient noncovalent functionalization of single-walled carbon nanotubes (SWNTs) with a series of 3d metal(II) phthalocyanines Me(II)Pc, where Me= Co, Ni, Cu, and Zn. The functionalization can be performed in a temperature range of 400-500 °C under moderate vacuum and requires about 2-3 h only. The functionalized materials obtained were characterized by means of Fourier-transform infrared (FTIR), Raman, UV-visible and energy-dispersive X-ray spectroscopy (EDS), scanning and transmission electron microscopy (SEM and TEM, respectively) and thermogravimetric analysis (TGA). TGA suggested that Me(II)Pc weight content is 30%, 17% and 35% for NiPc, CuPc, and ZnPc, respectively (CoPc exhibited anomalous thermal decomposition behavior). The above values are consistent with those estimated from EDS spectra, namely, of 24-39%, 27-36% and 27-44% for CoPc, CuPc, and ZnPc, respectively. A strong increase in intensity of D band in the Raman spectra of SWNT‒Me(II)Pc hybrids, as compared to that of pristine nanotubes, implies very strong interactions between Pc molecules and SWNT sidewalls. Very high absolute values of binding energies of 32.46-37.12 kcal/mol and the highest occupied and lowest unoccupied molecular orbital (HOMO and LUMO, respectively) distribution patterns, calculated with density functional theory by using Perdew-Burke-Ernzerhof general gradient approximation correlation functional in combination with the Grimme’s empirical dispersion correction (PBE-D) and the double numerical basis set (DNP), also suggested that the interactions between Me(II) phthalocyanines and nanotube sidewalls are very strong. The authors thank the National Autonomous University of Mexico (grant DGAPA-IN200516) and the National Council of Science and Technology of Mexico (CONACYT, grant 250655) for financial support. The authors are also grateful to Dr. Natalia Alzate-Carvajal (CCADET of UNAM), Eréndira Martínez (IF of UNAM) and Iván Puente-Lee (Faculty of Chemistry of UNAM) for technical assistance with FTIR, TGA measurements, and TEM imaging, respectively.

Keywords: carbon nanotubes, functionalization, gas-phase, metal(II) phthalocyanines

Procedia PDF Downloads 99

Authors: Gina Zavaleta-Espejo, Segundo R. Jáuregui-Rosas, Fanny V. Samanamud-Moreno, José Saldaña Jiménez, Anibal Felix-Quintero, Víctor Montero-Del Aguila, Elsi Mejía-Uriarte

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Vicugnapacos "alpaca" fabrics are considered special for their finesse, and the garments in the textile market are very luxurious. It has many special characteristics such as antiallergic, soft, hygroscopic, among others. In this sense, the research aimed to evaluate the antimicrobial activity of alpaca fabrics functionalized with silver nanoparticles on the bacteria Escherichia coli ATCC 25922 and Staphylococcus aureus ATCC 25923. For the functionalization of the fabrics, AgNO3 and different concentrations of trisodium citrate (TSC) 2, 6, and 10 mg. Tissue characterization was performed using Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). The determination of the antimicrobial activity of the alpaca tissues was made by the Kirby-Bauer method with alpaca tissue discs functionalized with silver nanoparticles, an experimental design was made in completely randomized blocks with three treatments and a negative control with three repetitions. The results showed that inhibition halos were formed for both bacteria, therefore, the functionalized tissues have a high antimicrobial activity, whose mechanism of action is attributed to the free radicals (ROS) generated by the nanoparticles that cause oxidative damage to the bacteria. proteins and lipids of the bacterial cell wall.

Keywords: antimicrobial, animal fibers, fabrics, functionalization, trisodium citrate

Procedia PDF Downloads 108

Authors: Samy M. Shaban, Ismail Aiad, Mohamed M. El-Sukkary, E. A. Soliman, Moshira Y. El-Awady

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In situ and green synthesis of cubic and spherical silver nanoparticles were developed using sun light as reducing agent in the presence of newly prepared cationic surfactant which acting as capping agents. The morphology of prepared silver nanoparticle was estimated by transmission electron microscope (TEM) and the size distribution determined by dynamic light scattering (DLS). The hydrophobic chain length of the prepared surfactant effect on the stability of the prepared silver nanoparticles as clear from zeta-potential values. Also by increasing chain length of the used capping agent the amount of formed nanoparticle increase as indicated by increasing the absorbance. Both prepared surfactants and surfactants capping silver nanoparticles showed high antimicrobial activity against gram positive and gram-negative bacteria.

Keywords: photosynthesis, hexaonal shapes, zetapotential, biological activity

Procedia PDF Downloads 427

Authors: Mrinalini Amritkar, Disha Patil, Swapna Kulkarni, Sukratu Barve, Suresh Gosavi

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Micro-mixers play an important role in the lab-on-a-chip applications and micro total analysis systems to acquire the correct level of mixing for any given process. The mixing process can be classified as active or passive according to the use of external energy. Literature of microfluidics reports that most of the work is done on the models of steady laminar flow; however, the study of unsteady laminar flow is an active area of research at present. There are wide applications of this, out of which, we consider nanoparticle synthesis in micro-mixers. In this work, we have developed a model for unsteady flow to study the mixing performance of a passive micro mixer for reactants used for such synthesis. The model is developed in Finite Volume Method (FVM)-based software, OpenFOAM. The model is tested by carrying out the simulations at Re of 0.5. Mixing performance of the micro-mixer is investigated using simulated concentration values of mixed species across the width of the micro-mixer and calculating the variance across a line profile. Experimental validation is done by passing dyes through a Y shape micro-mixer fabricated using polydimethylsiloxane (PDMS) polymer and comparing variances with the simulated ones. Gold nanoparticles are later synthesized through the micro-mixer and collected at two different times leading to significantly different size distributions. These times match with the time scales over which reactant concentrations vary as obtained from simulations. Our simulations could thus be used to create design aids for passive micro-mixers used in nanoparticle synthesis.

Keywords: Lab-on-chip, LOC, micro-mixer, OpenFOAM, PDMS

Procedia PDF Downloads 135

Authors: Spartak Makovskyi, Volodymir Klochykhin, Valery Zakharchenko, Konstantyn Balushok, Eduard Tsyvirko, Anatoly Shalomeyev

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A highly efficient, cost-effective grain refinement technique for ML5 magnesium alloy with a commercially pure carbon nanopowder has been proposed. An experimental casting of testing specimens with incremental additions of a carbon nanopowder (0.001 - 0.1 wt.% ) was performed. It has been found that the carbon nanoparticle inoculation of the alloy structure is efficient in a narrow concentration range. The additions of 0.005-0.01 wt. % the grain refiner in the alloy resulted in a maximum increase of ductility properties (appr. Twofold) and improved tensile strength. However, further expansion of the grain refiner content led to the deterioration of the alloy's mechanical properties. In particular, the introduction of 0.1 wt.% of the nanocarbon and more caused internal defects in the metal. The carbon nanoparticle inoculation is a promising way of improving the properties of the Mg-Al-Zn alloys for critical lightweight aerospace applications on an industrial scale.

Keywords: carbon nanopowder, inoculation, melt, tensile strength

Procedia PDF Downloads 176