Mixture Of Nanoparticles Research Articles

Robust, Fluorine-Free Superhydrophobic Films on Glass via Epoxysilane Pretreatment.

Durable and fluorine-free superhydrophobic films were fabricated by a simple two-step process involving the pretreatment of glass substrates with an epoxysilane, which acted as an adhesive. The next step involved the aerosol-assisted chemical vapor deposition of a simple mixture of polydimethylsiloxane (PDMS) and SiO2 nanoparticles (NPs). Various parameters were studied, such as deposition time as well as PDMS and SiO2 loadings. The optimum film generated was with a 1:1 loading of PDMS and SiO2, deposited at 360 °C for 40 min. The resultant film demonstrated excellent water repellency with a water contact angle of 165 ± 3° and a sliding angle of 2°. The epoxysilane underlayer provided the adhesion between the film and substrate. The films maintained superhydrophobicity and durability after being exposed to solvents such as diethyl ether, toluene, and ethanol for up to 5 h, 400 tape peel cycles, UV exposure, and heat exposure at 400 °C. The robustness results indicated enhanced durability relative to the superhydrophobic film without the epoxysilane underlayer.

Geothermal viscosity in unsteady hydro-magnetic boundary layer flow of Casson fluid conveying nanoparticle mixture

Geothermal viscosity in unsteady hydro-magnetic boundary layer flow of Casson fluid conveying nanoparticle mixture

Toward Resolving Heterogeneous Mixtures of Nanocarriers in Drug Delivery Systems through Light Scattering and Machine Learning.

Nanocarriers (NCs) have emerged as a revolutionary approach in targeted drug delivery, promising to enhance drug efficacy and reduce toxicity through precise targeting and controlled release mechanisms. Despite their potential, the clinical adoption of NCs is hindered by challenges in their physicochemical characterization, essential for ensuring drug safety, efficacy, and quality control. Traditional characterization methods, such as dynamic light scattering and nanoparticle tracking analysis, offer limited insights, primarily focusing on particle size and concentration, while techniques like high-performance liquid chromatography and mass spectrometry are hampered by extensive sample preparation, high costs, and potential sample degradation. Addressing these limitations, this work presents a cost-effective methodology leveraging light scattering and optical forces, combined with machine learning algorithms, to characterize polydisperse nanoparticle mixtures, including lipid-based NCs. We prove that our approach provides quantification of the relative concentration of complex nanoparticle suspensions by detecting changes in refractive index and polydispersity without extensive sample preparation or destruction, offering a high-throughput solution for NC characterization in drug delivery systems. Experimental validation demonstrates the method's efficacy in characterizing commercially available synthetic nanoparticles and Doxoves, a liposomal formulation of Doxorubicin used in cancer treatment, marking a significant advancement toward reliable, noninvasive characterization techniques that can accelerate the clinical translation of nanocarrier-based therapeutics.

Individual and Dual Cytotoxicity of the Combination of Passiflora Caerulea Leaf Extract and Titanium Oxide Nanoparticles against A549, U937, and Hela Cells

Background: The study addresses the underexplored realm of cytotoxicity evaluation involving binary mixtures of Passiflora caerulea leaf extracts and Titanium nanoparticles (TiO2NPs). The focus lies on understanding the combined effects of these components on cancer cells (A549, U937, and HeLa). Methods: In vitro cytotoxicity assessments were employed to evaluate the toxicity of P. caerulea leaf extracts, TiO2NPs, and their combination. The study utilized MTT, NRU, and LDH assays to measure cellular viability. Additionally, reactive oxygen species (ROS) and glutathione levels were assessed alongside the aforementioned assays. Results: The toxicity percentage exhibited dose-dependent behavior for P. caerulea leaf extracts, TiO2NPs, and their combination. Interestingly, when P. caerulea leaf extract and TiO2NPs were combined, the reduction in cell viability was noticeably more than when the exposures were made separately. Moreover, the production of ROS was higher in the combined toxicity scenario, and a more pronounced decrease in glutathione levels was observed compared to individual exposures. Conclusion: The findings suggest that the combined effects of P. caerulea leaf extract and TiO2NPs induce greater cytotoxicity compared to their impacts. This underscores the potential for synergistic cytotoxicity in combined exposure scenarios, warranting further exploration of combined effects in future studies.

Green synthesis of novel chitosan-graphene oxide-silver nanoparticle nanocomposite for broad-spectrum antibacterial applications

Abstract In this study, a novel nanocomposite composed of chitosan, graphene oxide, and silver nanoparticles (CS-GO-Ag NPs) is presented and synthesized using pulsed laser ablation. Characterization techniques, including X-ray diffraction (XRD), Field Emission Scanning Electron Microscopy (FE-SEM), Energy Dispersive Spectroscopy EDX, and UV-visible spectroscopy, confirm successful synthesis. The XRD results reveal that the CS-GO-Ag NPs exhibit crystalline structures with an average crystallite size of approximately 30 nm. FE-SEM analysis shows a heterogeneous mixture of nanoparticles, ranging in size from 32.38 to 174.9 nm. The EDX spectra elucidate the elemental composition, while UV-Vis spectroscopy indicates strong interactions among the components, yielding a direct bandgap of 2.33 eV and an indirect bandgap of 1.2 eV, suggesting efficient light absorption and emission for applications in Light emitted Diode (LEDs) and solar cells. Furthermore, the CS-GO-Ag NPs nanocomposite displays enhanced antibacterial activity against both gram-negative and gram-positive bacteria when it compared to its individual components. According to characterization tests, well-dispersed silver nanoparticles were formed into a ternary nanocomposite, successfully. The enhanced antibacterial capabilities including increased bacterial cell membrane disruption and oxidative stress can be attributed to the synergistic interaction between the components. The outcomes highlight the CS- GO-Ag NPs nanocomposite's potential as a promising antimicrobial agent for numerous applications including the biomedical fields and water treatment industries.

A comparative study of Cu-based nanoparticles and their spin-coated films: photocatalytic degradation mechanisms and efficiencies towards malachite green and neutral red azo dyes.

In this work, a comparison of the photocatalytic activity of free-standing Cu-based nanoparticle mixtures and spin-coated nanoparticle films under visible-light radiation is conducted. Herein, Cu2O, Cu2O-Cu, Cu2O-Cu3N-Cu, and Cu3N-Cu nanoparticle mixtures were successfully synthesized by a non-aqueous sol-gel route and then deposited on a glass substrate by spin-coating. The surface chemistry of the nanoparticles studied by X-ray photoelectron spectroscopy (XPS) allowed elucidating the nanoparticle synthesis mechanism. The UV-Vis absorption spectroscopy illustrates that photocatalytic activity is attributed to the high specific surface of the nanoparticles and their wider absorption range region from 500 to 1100nm. Unlike the free-standing photocatalysts, the photocatalytic effect of spin-coated nanoparticle films enabled their facile reclamation, which solves a key issue for practical applications of the photocatalysts. The photocatalytic performances on neutral red and malachite green organic dyes were influenced by the type of visible light sources, i.e., solar simulator and natural sunlight. The results indicate that photodegradation efficiency is the highest for Cu2O nanoparticles, reaching values of 82% for neutral red and 94% for malachite green. We also demonstrate that the degradation of cationic neutral red undergoes a photoconversion to its neutral form during the degradation process, which in turn, lowers its degradation efficiency. On the other hand, higher degradation efficiency was observed on malachite green owing to its unique cationic form, soluble in aqueous solutions.

Phase characterisation in minerals and metals using an SEM-EDS based automated mineralogy system

Abstract Advanced Mineral Identification and Characterisation System (AMICS) is based on energy dispersive X-ray spectroscopy (EDS) utilised in a scanning electron microscope (SEM). A specially designed software controls the sample positioning inside the microscope chamber, EDS spectra acquisition and analysis, phase identification, and results visualisation in the form of maps, graphs and tables. Characterisation can be conducted automatically for up to 28 mounted samples in a Hitachi SU3900 SEM with or without coating. Many options exist for an experienced researcher to influence the analysis process: (i) extract a spectrum for each acquisition point and determine chemical composition at this point, (ii) visualise mineral maps for each phase or a group of phases to characterise their interactions, (iii) determine the particle geometry-chemistry relationship, (iv) conduct statistical analysis of EDS spectra, define presence of solute elements, and visualise distribution of particles with a particular chemical composition, (v) manually develop the spectra database for unknown phases and solid solutions. This paper briefly outlines the AMICS software features and selected results for phase characterisation in minerals, metal alloys, and nanoparticle mixtures (MOFs and ZIFs). The influence of data acquisition methodology on accuracy and depth of characterisation is discussed.

Nanocomposites Based on Disentangled Ultra-High Molecular Weight Polyethylene: Aspects and Specifics of Solid-State Processing.

The stages of solid-state processing of nanocomposites, based on nascent disentangled ultra-high-molecular-weight polyethylene (d-UHMWPE) reactor powders (RPs) and carbon nanoparticles (NPs) of various types, were meticulously investigated. The potential for optimizing the filler distribution through variation of the processing parameters, and the impact of the d-UHMWPE RP and nanofiller type on the electrical conductivity of the resulting composites were discussed. The specifics of the dependences of conductivity and tensile strength on the deformation ratio for the composites, oriented under homogeneous shear conditions, were investigated. The obtained results and the results on piezoresistivity and temperature dependency of conductivity in the oriented and compacted composites demonstrated the independence of the UHMWPE matrix orientational strengthening on the filling. The interchangeability of high-temperature uniaxial deformation and deformation under homogeneous conditions for orientational strengthening and electrical conductivity changes in the preliminary oriented composite samples was confirmed. The potential for simultaneously achieving high strength and conductivity in composite tapes and the possibility of directly processing d-UHMWPE RP and NPs mixtures into oriented composite tapes were demonstrated. The overall results suggest that the studied composites may serve as a viable model system for investigating the deformational behavior of conductive networks comprising NPs of varying types and contents.

A new metrology tool: using transmission Kikuchi diffraction (TKD) to identify and separate nanoparticles for regulatory purposes

Abstract The development of methods for characterising nanoparticles (NPs) at the nanometric scale is a major challenge facing metrology researchers today. The characterisation of the crystal structure of NPs for regulatory purposes is urgent as mixtures of NPs are frequently found in consumer products and this physicochemical parameter contributes to the understanding of potential health and environmental risks. Using the methods currently available, NPs cannot be individually identified and their size distribution cannot be correlated to crystallographic phases. Instead, a general identification of crystallographic phases is possible. New methods must be developed that identify individual particles on the nanoscale. This paper introduces transmission Kikuchi diffraction, an electron backscattered diffraction (EBSD) technique as a method for comprehensively characterizing a mixture of iron oxide NPs by crystal structure. After identifying the crystal structure of three different iron oxide powders using x-ray Diffraction, the samples were characterised by TKD. The results underline the relevance of TKD, which has sufficient spatial resolution to determine the crystal structure of individual NPs. This study also demonstrates the possibility of electron backscattered diffraction analysis on unpolished samples, something atypical for EBSD and TKD. The powders were then mixed and the individual NPs were correctly identified in a scanning electron microscope (SEM) using TKD. The results show that TKD can be used to correctly identify and classify NPs within a mixture and can be combined with SEM imaging to build size distribution histograms according to the NP crystal structure.

Stability scrutinization of a non‐Newtonian (Williamson) ternary hybrid nanofluid past a stretching/shrinking sheet

AbstractThe thermal superiority of ternary hybrid nanofluids (THNFs) over conventional heat transfer fluid has led to growing interest in their applications. This new type of nanofluid can be customized for cooling systems, heat exchangers, and electronic cooling by carefully selecting nanoparticle types and their volume fraction. Hence, this study seeks to investigate the Heimenz flow in a Williamson THNF over a sheet that stretches or shrinks. The fundamental objective is to assess the effect of the stretching/shrinking parameter, the Weissenberg number, and the nanoparticle volume fraction on the physical quantities and flow profiles. Besides, attention is also given to the occurrences of multiple solutions in this fluid flow situation. By employing a similarity transformation, the governing equations are modified as a simpler form of ordinary differential equations (ODEs). Next, the numerical method is put to use to solve the resulting ODEs system, specifically the bvp4c solver in MATLAB. Significant changes in heat transmission occur due to variations in the Weissenberg number and volume fractions of nanoparticles, particularly when the sheet starts to shrink. The escalating Weissenberg number correlates with growing critical values of the stretching/shrinking parameter, suggesting that both parameters help to hold off the detachment of the boundary layer. These findings emphasize the capacity of THNFs to improve heat transfer performance in numerous applications. This study also reveals that while stretching sheets often have unique solutions, a shrinking sheet has multiple solutions when the shrinking parameter falls within a certain range. By scrutinizing the robustness of these solutions, it was concluded that only one of them maintains stability over an extended period. It is essential to highlight that these present discoveries apply exclusively to the mixture of copper, alumina, and titania. Various mixtures of nanoparticles can demonstrate distinct characteristics of THNFs concerning both flow dynamics and thermal transfer.

Contribution of Soret and Dufour aspects on Hybrid Nanofluid over 3D Magneto Radiative Stretching Surface with Chemical Reaction

This study analyzes Soret and Dufour impacts on 3-dimensional, rotating HNF (CuO-Ag/Water) flow over a linearly stretchable surface that contains a mixture of Ag and CuO nanoparticles with H2O acting as the base fluid. Flow of governing PDEs is transformed into a system of ODEs, by using the bvp5c approach. Analysis and graphical presentation were made of the effect of the parameters included. The present study reveals that the Soret factor affects the surface's thermal efficiency whereas the Dufour impact lessens the surface mass transfer. The present work 99.9% compatible with previous work for stretching sheet parameter values are 0, 0.1, 0.2, 0.3, 0.4, 0.5. This conclusion may be employed in a variety of nanofluid cooling systems. This study may be used to inform future numerical and experimental studies.

Suppression of H2O2 Formation and Durability of Various H2-Anode Catalysts for Long-Life PEFCs

Chemical decomposition of polymer electrolyte membranes (PEMs) by a radical attack is a significant issue affecting long-term durability of PEMs.1 Hydroxyl radicals (·OH) are generated via the reaction of H2O2 with impurities (such as Fe2+ and Cu2+ ions) present in the PEM. Hydrogen peroxide is produced when oxygen (crossover through PEM from the cathode) reacts with adsorbed hydrogen (Had) at Pt nanoparticles (NPs) supported on carbon (Pt/C) used for the hydrogen oxidation reaction (HOR) at the anode.2 In the present work, we examined the H2O2 production rates j(H2O2) and HOR activities on various anode catalysts developed in the NEDO (New Energy and Industrial Technology Development Organization of Japan) project. The catalysts examined are PtCo/CHT (PtCo NPs supported on acetylene black, followed by heat-treatment),3 Pt/Ti4O7-C (Pt NPs supported on Magnèli-phase Ti4O7, plus amorphous carbon),4 and commercial Pt/CB (c-Pt/CB, Pt NPs supported on carbon black) with addition of WO3 5 or IrO2 nanosheet.6 The values of j(H2O2), electrochemically active surface area (ECSA), kinetically-controlled mass activity MA k and specific activity j k for the HOR on Nafion-coated anode catalysts were measured by use of 0.1 M HClO4 electrolyte solution in a half-cell (channel flow double electrode cell technique) at 80 °C.3 An accelerated stress test (AST) for start/stop cycles7 was also examined.The initial values of j(H2O2) at E = 0.02 V vs. RHE (practical anode potential for the HOR) and HOR activities on various catalysts are summarized in Table I. All the developed catalysts exhibited an excellent initial property of lower j(H2O2) than that of c-Pt/CB. Among them, the PtCo/CHT catalyst exhibited the lowest j(H2O2), i.e., nearly 1/5 that of c-Pt/CB. It was also found that the value of j k for the HOR at PtCo/CHT was ca. 1.3 times higher than that at c-Pt/CB. For the case of Ptskin‒PtCo/C, it was clarified that both low j(H2O2) and high j k for the HOR was ascribed to the weakened adsorption of Had, which might be caused by the modified electronic properties of the Pt-skin surface due to the presence of underlying Co.3, 7 Studies on the change in the adsorption energy of Had at the PtCo/CHT catalyst are under progress.The Pt/Ti4O7-C catalyst also exhibited lower j(H2O2) together with higher j k for the HOR than those of c-Pt/CB. The electronic state of Pt was found to be modified by the Ti4O7 support.4 Such a modified electronic state of Pt could contribute to suppress the H2O2 production, similar to the case of Ptskin‒PtCo/C.It was found that a physical mixture of WO3 NPs or IrO2(ns) with c-Pt/CB also suppressed H2O2 production. The role of WO3 can be a promotion of Had spillover from the Pt surface to form HxWO3, while the j k for the HOR was not so affected. It is also envisioned that H2O2 production might be suppressed by the addition of IrO2 nanosheets and WO3 via formation of a complex with H2O2 due to their interaction, similar to the case of silica NPs.8 The lowest j(H2O2) on PtCo/CHT was maintained during the AST (potential sweep cycles between 0.02 V and 1.0 V) of 6000 cycles. The analysis of degradation behavior of every catalyst is under progress, taking all properties (j(H2O2), MA k, j k, and ECSA) into account.This work was supported by funds for the “R&D of novel anode catalyst project” from the New Energy and Industrial Technology Development Organization (NEDO) of Japan. References B. LaConti, M. Hamdan and R. C. McDonald, Handbook of Fuel Cells, ed. W. Vielstich, A. Lamm, and H. Gasteiger (Wiley, Chichester, England), 3 , p. 647 (2003).Zatoń, J. Rozière, and D. J. Jones, Sustain. Energy Fuels, 1, 409 (2017).Shi, D. A. Tryk, T. Iwataki, H. Yano, M. Uchida, A. Iiyama and H. Uchida, J. Mater. Chem. A, 8, 1091 (2020).Chisaka, W. Nagano, B. Delgertsetseg, and T. Takeguchi, Chem. Commun., 57, 12772 (2021).P-Yves Olu, T. Ohnishi, Y. Ayato, D. Mochizuki, W. Sugimoto, Commun., 71, 69 (2016).Takimoto, K. Fukuda, S. Miyasaka, T. Ishida, Y. Ayato, D. Mochizuki, W. Shimizu, and W. Sugimoto, Electrocatalysis, 8, 144 (2017).Shi, H. Yano, D. A. Tryk, A. Iiyama, and H. Uchida, ACS Catal., 7, 267 (2017).M. R. Berber, M. Imran, H. Nishino, and H. Uchida, ACS Appl. Mater. Interfaces, 15, 13219 (2023). Figure 1

Enhancing the Thermophysical Properties of Lubricating Oils of Refrigeration System Using CuO/CeO2 as a Mixture of Nanoparticles

The compressor is the heart of the refrigeration system, extension of its life and preservation of its moving parts such as pistons, rotors, valves, connecting rods and cranks lubrication require improvement. Recently the studies focus on the use nanoparticles with lubricants in refrigeration and air conditioning systems in view of their significant impact on improving the coefficient of performance of these systems as well as thermophysical properties of pure lubricating oils and thus reducing energy consumption. In this study, nanoparticles were synthesized in an easy and cheap way and from materials available in chemistry laboratories as following copper oxide, cerium oxide, mixture 1 consisted of 50% copper oxide with 50% cerium oxide, mixture 2 consisted of 60% copper oxide with 40% cerium oxide, mixture 3 consisted of 70% copper oxide with 30% cerium oxide, mixture 4 consisted of 40% copper oxide with 60% cerium oxide, and mixture 5 consisted of 30% copper oxide with 70% cerium oxide to study their effectiveness on enhancing the thermophysical properties of POE, PAG lubricating oil using mathematical equations available from earlier studies. The results obtained from the mathematical equations showed an increase in the viscosity of POE from 40 mm2/sec to 45 mm2/sec at 0.05 wt.% and reached 108.86 mm2/sec by increasing the concentration of nanoparticles to 0.33wt.%, as well as the improvement of viscosity of PAG from 46 mm2/sec to 52.9 mm2/sec at the concentration of nanoparticles 0.05 wt.%, recording a significant improvement when the concentration of nanoparticles reached 0.33 wt.%, as well as for the rest of the other physical properties. This is consistent with earlier studies that confirmed the improvement of the physical properties of lubricants through mixing them with nanoparticles.

Differential Leaf-to-Root Movement, Trophic Transfer, and Tissue-Specific Biodistribution of Metal-Based and Polymer-Based Nanoparticles When Present Singly and in Mixture.

The transfer of nanoparticles (NPs) through the terrestrial food chain via foliar uptake presents poorly understood risks, especially in scenarios involving copollution and plant translocation. Herein, we exposed the radishes to single and mixed foliar doses of CeO2 NPs and deuterated polystyrene (DPS), investigating the trophic transfer of NPs from radish shoots/roots to snails. Compared to single treatments, mixture treatments increased Ce uptake by plants but had no effect on DPS uptake. Additionally, mixture treatments did not affect the movement of Ce and DPS from shoots to roots. Under NP mixture exposure, trophic transfer efficiencies (TTF) for Ce (2.09 × 10-2) and DPS (2.54 × 10-2) significantly decreased in shoot-feeding snails. In root-feeding snails, TTF for Ce (3.32 × 10-1) also showed a significant decrease, while TTF for DPS remained unchanged. Mixture treatments exhibited differential impacts on different snail body parts, particularly leading to biomagnification of DPS in the digestive glands and soft tissues (TTF > 1) of snails consuming roots exposed to mixtures. Both CeO2 and DPS displayed a sudden increase in assimilation efficiency following translocation to the roots. This study provides insights into changes during trophic transfer due to coexposure and plant translocation processes associated with nanoparticles, enhancing our comprehension regarding their environmental risks.

Impact of Thermal Energy on Water and Ethylene Glycol (50:50)-Based Rotating Hybrid Nanofluid Past A Riga Surface with Radiation, Homogeneous and Heterogeneous Reactions

Hybrid nanofluid is crucial in improving the efficiency of heat transmission in thermal engineering applications, particularly the cooling of electrical equipment, heat exchangers, fuel cells, printing machines, etc. This study sought to investigate the augmentation of heat and mass transmission by the use of a rotating hybrid nanofluid consisting of a mixture of gold and silver nanoparticles suspended in water and ethylene glycol (50:50) past a heated Riga surface with velocity slip and suction. The energy equation is constructed using nonlinear radiation and heat consumption. The impact of both homogeneous and heterogeneous processes on the hybrid nanofluid is also explored. The governing mathematical model begins with partial differential equations that are converted into ordinary differential equations using a suitable conversion technique. The results of numerical computations are recorded as graphs and tables using the bvp4c scheme in MATLAB. It is noticed that both directional velocities undergo significant negative changes as a result of enhanced values of the rotational parameter. The higher levels of the radiation parameter resulted in significant enhancements in the thermal profile. The falling behavior of the nanoparticle concentration profile is recorded against a greater quantity of both chemical reaction parameters. Based on our analysis, when the Biot number changes from 0.4 to 0.8, the most significant heat transmission gradient occurs.

Isotopic labeling of nanoparticles for the evaluation of their environmental fate in mesocosm experiments

Mesocosm systems simulating floodplain areas are essential for the understanding of the environmental fate and effects of engineered nanoparticles (ENPs). In such mesocosm studies, the quantification of different types of nanoparticles coexisting in natural systems and containing the same element is often challenging. Such coexistence is expected e.g., for ENPs simultaneously released into the environmental systems. Despite the relevance of the coexistence, little is known about combined behavior and effects of ENPs in the environment. In this study, we developed a method for the quantification and differentiation of silver nanoparticles enriched by 109Ag isotope (109Ag-NPs) and sulfidized silver nanoparticles with natural isotopic distribution (S-Ag-NPs) in water, soil, and sediment and applied it to evaluate the environmental fate of these nanoparticles introduced simultaneously together with gold (Au-NPs) and titanium dioxide (TiO2-NPs) nanoparticles into mesocosms simulating an aquatic-terrestrial transition zone. High nanoparticle recoveries determined in water, sand, and soil spiked with nanoparticle mixtures indicate that the application of isotopically enriched ENPs will allow their differentiation from other nanoparticles containing the same element in environmental compartments even at the concentrations in the range of natural background. The co-accumulation of 109Ag-NPs, S-Ag-NPs, and Au-NPs in the top layer of sediment and soil and in biofilms observed in mesocosm studies suggests that these compartments can act as effective sinks for these ENPs. We suggest that the hetero-aggregation between different co-occurring ENPs and their high affinity to biota are major mechanisms controlling their fate in the aquatic-terrestrial transition zone. A high co-enrichment of 109Ag-NPs, S-Ag-NPs, Au-NPs, and TiO2-NPs in/on algae, biofilms, leaves, and amphipods suggests an enhanced risk of biomagnification. The findings of this study will contribute to a better understanding of the fate of ENPs and their combined effects in environmental compartments, where the simultaneous presence of diverse nanoparticles is expected.

Concentrated Solar Power Plant using air blended with nanoparticles as working fluid

Abstract Adopting efficient power plants based on renewable energy sources is extremely important to face the challenges of global warming. Concentrated Solar Power Plant (CSP) is a technology option that can achieve the decarbonization target of the electricity sector in large power plants and simultaneously meet the growing demand for electricity. In this study, a CSP plant using air as heat transfer fluid, whose transformations realize a Discrete Ericsson Cycle (DEC), was referenced. Solar fields are based on parabolic trough collectors. The DEC consists of a series of inter-cooled compressions and inter-heated expansions (four and two, respectively, in this paper), whose net result is a useful work. In this paper, a mixture of air and Cr2O3 nanoparticles at different particle concentration has been considered as working fluid to enhance the performances of the compression and expansion transformations in a DEC-based plant. The presence of particles cools the air during compression and heat the air during expansion, approaching isothermal processes. A sensitivity analysis referred to the particle concentration has been discussed and the power and the efficiency of the plant have been discussed outlining benefits and drawbacks. Nanoparticle concentration less that 0,05% in volume (10 % in mass) produce a power and efficiency output increase close to 3 % without any sensible constraint. At higher concentrations, more significant variations are achieved with a 15 % power output increase for a mass concentration of nanoparticles of 50%. Such mass concentration corresponds to just 0.05 % in volume, allowing a potential operativity of the turbomachines. In this condition, the overall CSP efficiency improve by 1.5 percentage points.

Enhancing the combustion of silicon nanoparticles via plasma-assisted fluorocarbon surface modification

Nanostructured silicon has great potential as an energetic material due to its high energy density, close to that of aluminum; however, its combustion kinetics are strongly affected by the presence of a native oxide layer. As the particle size is reduced, the material behavior is dominated by surface effects, highlighting the need for new approaches to fabricate silicon nanoparticles and precisely control their surface chemistry. Here, we describe the use of low-temperature plasma to nucleate and grow < 10 nm silicon particles. The resulting aerosol is passed through a second plasma reactor, to which a fluorocarbon monomer is supplied. The second plasma initiates the growth of a polymeric shell onto the silicon particles, resulting in a highly conformal coating. Chemical analysis confirms that the polymer shell is compositionally similar to polyvinylidene fluoride (PVDF). We find that the fluorocarbon shell acts as an artificial passivation layer that significantly delays the onset of oxidation in air. In addition, the direct contact between the fluorocarbon shell and silicon core lowers the ignition temperature compared to the physical mixtures of silicon nanoparticles and PVDF. It leads to a higher pressurization rate and a lower combustion time when tested in a combustion cell. This is consistent with the combustion process being initiated by the exothermic interfacial reactions between the silicon core and the fluorocarbon shell. Mass spectroscopy confirms this hypothesis because silicon fluoride is produced only for the core–shell structure, and not for a physical mixture of silicon and PVDF. This study provides an example of a new processing technique capable of controlling the interfacial chemistry of small nanoparticles with beneficial effects on their combustion.

Self-Nanoemulsifying/ Self-Assembled Cubic Nanoparticles Lyophilized Tablet: A Novel Biphasic Release Approach to Enhance the Bioavailability of a Lipophilic Drug

This study aimed to prepare a combined self-nanoemulsifying and self-assembled cubic nanoparticles (SNE/SAC) lyophilized tablet eliciting biphasic release pattern escorted with enhanced bioavailability for drugs hampered with slow dissolution and poor absorption. The antimuscarinic Darifenacin hydrobromide (DRF) was selected as a model drug used to treat overactive bladder-associated nocturia. The DRF-SNE/SAC lyophilized tablet was prepared so that upon reconstitution a mixture of DRF-loaded cubic nanoparticles and nanoemulsion dispersion is obtained. The nanoemulsion portion is responsible for the fast release followed by controlled release of the remaining dose loaded in cubic nanoparticles. A comparative pharmacokinetic study adopting randomized crossover design in male albino rabbits versus marketed product Frequefenacine® tablet was performed. Half of the dose (52.05% ± 4.21%) was rapidly released in the first 4 h followed by sustained release of the remaining drug where (90.16% ± 8.85%) was released in 24 h. The tested system showed 2.45 folds higher % relative bioavailability and 1.57 folds higher Cmax with 1.62 longer residence time relative to reference product. The results endow the ability of the developed DRF-SNE/SAC lyophilized tablet to be considered as a propitious approach for the treatment of overactive bladder-associated nocturia without midnight dose administration.Graphical

Heat transportation phenomena subject to Ellis fluid over a spinning body: A dynamics of trihybrid nanoparticles

AbstractThe boosting of base fluid thermal transport is a remarkable significance in the current research era, and numerous types of techniques are being utilized to achieve this goal. The mixture of nanoparticles inside the host fluid is responsible to improve base fluid thermal performance. The modified Buongiorno's nanofluid model is explored in the current study along with the significant trihybrid nanoparticle effect. The fundamental equations of the chosen flow model are transformed using a similarity transformation, and the succeeding equations are then resolved numerically using the discretization of Keller‐Box in MATLAB. The primary velocity profile is directly raised with large values of the Hartman number, unsteady, and Ellis's fluid parameters, while an inverse curves trend is reported in secondary velocity. The primary speed of fluid is significantly greater compared to di and mono‐hybrid cases, and this study reveals that optimal thermal transport is achieved against tri‐hybrid cases. The tri‐hybrid model has 9% improvement in Nusselt number when compared to single and two‐type nanoparticle fluid models.