Nanoparticles Of Different Materials Research Articles

Analysis of the performance of jacketed vessel using hybrid nanofluids in Aspen Plus

ABSTRACT Computer Simulation is used as an effective tool to analyse the performance of processes in industries. One such simulation tool, Aspen Plus, is used in this work to analyse the performance of a jacketed vessel along with the heat exchanger and pump for hybrid nanofluids. Hybrid nanofluids, are advanced fluids engineered by combining nanoparticles of different materials with base fluids like water, are introduced into the jacketed vessel with the primary objective of improving thermal management. The nanofluids are passed into the jacketed vessel to take away the heat of the fluid inside the vessel. The hot nanofluid coming out from the jacketed vessel is cooled using an air-cooled heat exchanger, and it is pumped again to the jacketed vessel. The performance of the jacketed vessel is compared with using water as a thermal fluid and the heat duty is found to be higher for nanofluids than water. The pressure drop and the velocity of the heat exchanger were also analysed for both hybrid nanofluids and water.

Effect of nanoparticles on the aggregation and amyloid formation of amyloid-beta peptide.

Nanoparticles are becoming more and more important in medicine and biotechnology. Moreover, due to environmental pollution, the human body is exposed to nanoparticles in the everyday life. Nanomaterials can also affect the aggregation processes of proteins. The Aβ peptides are known for forming amyloid aggregates in the brain in Alzheimer's disease. We used in-house expressed recombinant Aβ(1-42) to study the structure, aggregation kinetics and cytotoxicity of the peptide. We characterized nanoparticles of different materials and studied their effects on the structure and aggregation of Aβ. We followed amyloid formation by monitoring Thioflavin T fluorescence in the presence of nanoparticles. We observed that nanoparticles typically reduce the lag time of aggregation. We found that polystyrene particles bind monomers to a certain saturation point and allow only excess monomers to form fibrils. Calcium fluoride (CaF2) nanoparticles do not bind monomers in a similar fashion, but do influence the secondary structure composition of the resulting amyloid fibrils. We used CD spectroscopy and the BeStSel method to determine the secondary structure composition of the different forms of Aβ. While the main characteristics of Aβ fibrils formed alone is parallel β-sheet, in the presence of CaF2, Aβ forms significant amount of antiparallel β-structure as well. We also conducted cytotoxicity experiments to investigate if nanoparticles alter the toxic effect of Aβ on mouse hippocampal cells. Our preliminary findings suggest that studied particles might reduce cytotoxicity of Aβ if applied in very low concentrations.

In depth characterisation of the biomolecular coronas of polymer coated inorganic nanoparticles with differential centrifugal sedimentation

Advances in nanofabrication methods have enabled the tailoring of new strategies towards the controlled production of nanoparticles with attractive applications in healthcare. In many cases, their characterisation remains a big challenge, particularly for small-sized functional nanoparticles of 5 nm diameter or smaller, where current particle sizing techniques struggle to provide the required sensitivity and accuracy. There is a clear need for the development of new reliable characterisation approaches for the physico-chemical characterisation of nanoparticles with significant accuracy, particularly for the analysis of the particles in the presence of complex biological fluids. Herein, we show that the Differential Centrifugal Sedimentation can be utilised as a high-precision tool for the reliable characterisation of functional nanoparticles of different materials. We report a method to correlate the sedimentation shift with the polymer and biomolecule adsorption on the nanoparticle surface, validating the developed core–shell model. We also highlight its limit when measuring nanoparticles of smaller size and the need to use several complementary methods when characterising nanoparticle corona complexes.

Easily synthesizable benzothiazole based designers palladium complexes for catalysis of Suzuki coupling: Controlling effect of aryl substituent of ligand on role and composition of insitu generated binary nanomaterial (PdS or Pd16S7)

The present report is based on straightforward synthesis of molecular palladium complexes of benzothiazole based bulky ligands. Catalytic potential of 1[Pd(L1)2Cl2] and 2[Pd(L2)2Cl2] has been screened for Suzuki coupling. Due to structural difference between 1 and 2 (anthracen-9-yl in 1, and pyren-1-yl in 2), they behave as designers pre-catalysts and show different catalytic behaviour and nature by dispensing the nanoparticles of different materials (PdS by 1 and Pd16S7 by 2). This is an unprecedented observation as the size of the aryl substituent controls the efficiency (efficiency: 1 > 2) through determining the composition and nature of insitu generated nanoparticles.

Engine performance and emission studies by application of nanoparticles as additive in biodiesel diesel blends

The present paper investigates the effects of different nanoparticles blended with biodiesel on performance and emission characteristics of the diesel engine. However, inherent drawbacks like lower heating value, higher density, and viscosity while increased fuel consumption and NOx emissions limit the biodiesel application in engines. In this way, the additives in the form of nanoparticles of different materials play a prominent role to mitigate the drawbacks of biodiesel. The higher calorific value, thermal conductivity, and surface to volume ratio properties of nanoparticles enhanced the engine performance, combustion and emissions compared to neat biodiesel and biodiesel-diesel blends. This study uses five different Diesel, B20, B20CO, B20TO and B20COTO test fuels to be prepared at a different volume mixing ratio. It was concluded that by B20COTO nanoparticle additive fuel showed high BTE and reduced BSFC, HC and NOx emissions on a diesel engine as correlated to other fuels. B20CO fuel showed lower CO emissions as compared other fuels.

Theoretical assessment of a solar still system equipped with Nano-phase change materials

ABSTRACT Regarding water scarcity in recent decades, solar stills due to their environmental compatibility and economic viability received more attention. Through the current study, the performance of weir-type cascade solar still equipped with different phase change materials (PCMs) especially Nano-PCMs is evaluated. The utilized phase change materials are Stearic acid, Paraffin, and some kinds of PCMs that are enhanced with Nanoparticles of different materials. The Nano-enhanced PCMs are consisted of nePCM I (Paraffin+, nePCM II (Paraffin+CuO), and nePCM III (Paraffin+GO). The novelty of the present work can be attributed to the exegetic and energetic analysis of cascade solar still equipped with Nano-enhanced PCM as well as investigating the effects of climatic parameters on the performance of the system. Regarding the results, in brackish water mass flow rate of 0.07 and 0.4 kg/(m2.min), the system equipped with nePCM II has the energy and exergy efficiencies of 63.55, 6.4181, 56.79%, and 5.387, respectively. Moreover, for the mass flow rate of 0.2 and 0.3 kg/(m2.min) the nePCM I show higher energy efficiency compared to others. The maximum distilled water production belongs to nePCM II in the mass flow rate of 0.07 kg/(m2.min), which is 9.28 kg/(m2.hr). Besides, the results showed that at the ambient temperatures lower than 29°C, the system equipped with Stearic acid has better performance from an energetic and exergetic point of view. Finally, the best Azimuth angles for the system in the presence of different PCMs presented.

CVD-diamond nanoparticle synthesis for DLC film application

Diamond-like carbon (DLC) films have been extensively applied as a solid lubricant and as a protective coating due to their attractive chemical, mechanical, and tribological properties. Furthermore, these properties of DLC coatings can be improved with the incorporation of nanoparticles of different materials, especially diamond nanoparticles (DNPs). Herein, the incorporation of chemical vapor deposition (CVD) DNPs was done from a deionized aqueous colloidal solution by using a controlled pulsed valve, which is an innovative aspect of this work. The CVD DNPs were pulverized into the plasma region and incorporated in the DLC films bulk with controllable size particle distribution and density. In addition, an enhanced process to obtain DNPs with suitable size distribution was established by using a high energy ball milling technique, centrifugation, and a special chemical cleaning process. The DLC films were deposited on a metallic substrate via a modified, pulsed DC plasma-enhanced chemical vapor deposition (PECVD) technique, with an additional cathode. X-ray diffractometry (XRD) and scanning electronic microscopy (SEM) techniques showed that an aqueous colloidal solution of high-purity DNPs with a mean diameter of 32 nm was obtained. Dynamic light scattering (DLS) results showed that it is possible to control particle size distribution by varying the milling and centrifugation time lengths. Therefore, a valuable result was that DLC films could be deposited with DNPs by using clean water without affecting deposition rate, the adhesion between the DLC films and substrates, the structural quality of the film, and keeping lower coefficient of friction.

Natural convection of a hybrid nanofluid affected by an inclined periodic magnetic field within a porous medium

Heat transfer enhancement for various engineering systems can be achieved by the inclusion of metal nanoparticles inside the heat transfer liquid. Such an effect can be improved by considering the hybrid nanofluid when nanoparticles of different materials are added to the base fluid. The present study is devoted to computational analysis of thermal gravitational convection within a porous chamber under the impact of tilted periodic magnetic force. Governing equations formulated employing the single-phase nanoliquid approach, Brinkman-extended Darcy model for transport processes within the porous layer with the local thermal non-equilibrium approach, Boussinesq approximation for the description of the buoyancy force and magnetic field, have been resolved using the Galerkin finite element method. Impacts of the Darcy number, Hartmann number, Rayleigh number, periodicity of the magnetic field, magnetic field inclination angle, thermal conductivity ratio, and medium porosity on flow and thermal patterns have been examined. It has been found that parameters of the periodic magnetic field have the non-monotonic influence of the heat transfer performance.

Characterizations of absorption, scattering, and transmission of typical nanoparticles and their suspensions

Several numerical simulation models based on the finite element method (FEM) were established to understand the optical properties of nanoparticles and their suspensions, addressing UV–Vis spectra, scattering, absorption, and transmission. The studied nanoparticles covered gold (Au), silver (Ag), copper (Cu), silica (SiO2), titanium dioxide (TiO2), graphite and polystyrene, in their varied sizes and suspension concentrations. The extinction peak of UV–Vis spectrum and sizes of Au, Ag and Cu nanoparticles showed good linearity in certain size ranges, but not for other nanoparticles. Nanoparticles of different materials and sizes could also be distinguished by their scattering patterns and temperature variations due to absorption. Furthermore, the simplified model based on Lambert-Beer law was found to be effective in a good accuracy to describe both absorption and transmission properties of nanoparticle suspensions. Therefore, the optical properties of nanoparticles and their suspensions can be understood comprehensively and effectively by the established simulation methods.

A quick method for developing interparticle force models of spherical gold nanoparticles from molecular dynamics simulation

Understanding and quantification of the interactions between gold nanoparticles (AuNPs) allows us to explore their potentials for a wide range of applications. In present work, the interactions between AuNPs of size ranging from 3 nm to 20 nm are investigated by molecular dynamics (MD) simulation and their interparticle force models are developed from a quick and effective approach. Specifically, an external force is initially applied to a pair of spherical AuNPs at certain surface separation to accelerate their approaching toward each other. Such applied force is then removed at a certain distance, which can avoid the potential impact of such external force on the calculated interaction forces between AuNPs. Our results show that the attractive force dominates the interactions between spherical AuNPs. Such force increases exponentially with the decrease of particle surface separation prior to particle collision, which can be described quantitatively by simple mathematical force models. In addition, simulation on two AuNPs with different sizes shows that the smaller particle tends to merge onto the surface of larger one upon their collision. The reported approach provides a quick way to developing the interparticle force models between nanoparticles of different materials and shape, which is of importance in exploring nanoparticle systems and their self-assembly.

Role of nanoparticle materials as water-based lubricant additives for ceramics

Abstract The long running-in time and high wear of water-lubricated ceramics restrict their utility in the tribological field. Aqueous lubricant additives have been added to improve the tribological performance, but the effect of additive materials on the lubrication behavior is still unclear. In this study, nanoparticles of different materials were synthesized and tested for their tribological properties. The wear surfaces were systematically analyzed. The compatibility between the ceramic surface and the nanoparticles is indicated to be one of the key factors for good lubrication behavior. SiO2 nanoparticles performed cooperatively with the ceramic surface and significantly reduced the friction and wear, while ZnO and TiO2 could not form a homogenous protective film, leading to poor tribological performance.

Interferometric method for specific impulse determination

One of the main figures of merit in laser-ablative propulsion is the specific impulse, Isp, defined as the impulse per unit weight of fuel, and it is related to the exhaust velocity, ve, by the acceleration of gravity, Isp = ve / g. Being a key magnitude, Isp needs to be accurately determined. It is usually inferred from other measurable quantities: the impulse coupling coefficient, Cm, defined as the ratio of the target momentum produced to the incident laser pulse energy, and Q * , the laser energy consumed per unit weight of ablated target material. Thus, Isp is calculated as Isp = CmQ * / g. However, single pulse ablated mass leading to Q * is in the nanogram scale and cannot be directly measured by weighting the targets. So, mass loss measurements are performed by analyzing the volumes of the craters produced by a large number of laser pulses. These procedures lead to larger than desired uncertainties in the Isp values. On the other hand, more precise measurements of Isp can be carried out from the direct measurement of the exhaust velocity of the ejected particles by interferometric methods. In this work, a system based on a Nomarsky interferometer has been set up for the time-resolved diagnostic in the nanometric scale of laser ablation plumes. The performance of the implemented system was first validated by measuring the Isp produced by aluminum targets and solid propellants based on metal/salt mixtures. The Cm dependence on laser parameters and binary composition of these propellants have been determined in previous works with a torsion pendulum and a piezoelectric sensor. Once the interferometer performance is characterized, the Isp produced by solid propellants composed of metal (Zn) and metal oxides (ZnO) matrices doped with nanoparticles of different materials is determined and compared.

Analysis of natural convective flow of non-Newtonian fluid under the effects of nanoparticles of different materials

The purpose of this paper is to examine the effects of natural convection flow of viscoelastic polydimethylsiloxane non-Newtonian nanofluid under the impact of nanoparticles of different materials past a vertical cone. The implications for operating parameters have been investigated using tables and it is noticed that the nanoparticles unveil substantial impact on the thermal conductivity of base fluid. The temperature profile and the rate of heat transfer behave as an increasing function of nanoparticles. It is found that tiny size particles are more efficacious as compared to large particles on the rate of heat transfer and fluid motion. To validate the current methodology, a numerical comparison is posed with previously published data.

Quenching of material dependence in few-cycle driven electron acceleration from nanoparticles under many-particle charge interaction

The excitation of nanoscale near-fields with ultrashort and intense laser pulses of well-defined waveform enables strongly spatially and temporally localized electron emission, opening up the possibility for the generation of attosecond electron pulses. Here, we investigate the electron photoemission from isolated nanoparticles of different materials in few-cycle laser fields at intensities where the Coulomb field of the ionized electrons and residual ions significantly contribute to the electron acceleration process. The dependences of the electron cut-off energy on the material’s dielectric properties and electron binding energy are investigated systematically in both experiments and semi-classical simulations. We find that for sufficiently high near-field intensities the material dependence of the acceleration in the enhanced near-fields is quenched by many-particle charge-interaction.

Modeling of absorption and scattering properties of core -shell nanoparticles for application as nanoantenna in optical domain

The present paper describes the study of core-shell nanoparticles for application as nanoantenna in the optical domain. To obtain the absorption and extinction efficiencies as well as the angular distribution of the far field radiation pattern and the resonance wavelengths for these metal-dielectric, dielectric-metal and metal-metal core-shell nanoparticles in optical domain, we have used Finite Element Method based COMSOL Multiphysics Software and Mie Theory. From the comparative study of the extinction efficiencies of core-shell nanoparticles of different materials, it is found that for silica - gold core - shell nanoparticles, the resonant wavelength is greater than that of the gold - silver, silver-gold and gold-silica core - shell nanoparticles and also the radiation pattern of the silica-gold core-shell nanoparticle is the most suitable one from the point of view of directivity. The dielectric functions of the core and shell material as well as of the embedded matrix are extremely important and plays a very major role to tune the directivity and resonance wavelength. Such highly controllable parameters of the dielectric - metal core - shell nanoparticles make them suitable for efficient coupling of optical radiation into nanoscale structures for a broad range of applications in the field of communications.

Assembling Color on the Nanoscale: Multichromatic Switchable Pixels from Plasmonic Atoms and Molecules.

Nanoparticles of different materials, shapes, and sizes are integrated into plasmonic atoms and molecules of defined shape and location through sequential directed self-assembly following a single patterning step. A rational tuning of the emitted color across the visible range of the electromagnetic spectrum and switchable polarization properties are demonstrated. Self-assembled plasmonic pixels provide tunable, stable, and switchable optical responses.

Development of a new direct liquid injection system for nanoparticle deposition by chemical vapor deposition using nanoparticle solutions

Nanoparticles of different materials are already in use for many applications. In some applications, these nanoparticles need to be deposited on a substrate in a fast and reproducible way. We have developed a new direct liquid injection system for nanoparticle deposition by chemical vapor deposition using a liquid nanoparticle precursor. The system was designed to deposit nanoparticles in a controlled and reproducible way by using two direct liquid injectors to deliver nanoparticles to the system. The nanoparticle solution is first evaporated and then the nanoparticles flow onto a substrate inside the vacuum chamber. To allow injection and evaporation of the liquid, a direct liquid injection and vaporization system are mounted on top of the process chamber. The deposition of the nanoparticles is controlled by parameters such as deposition temperature, partial pressure of the gases, and flow rate of the nanoparticle suspension. The concentration of the deposited nanoparticles can be varied simply by changing the flow rate and deposition time. We demonstrate the capabilities of this system using gold nanoparticles. The selected suspension flow rates were varied between 0.25 and 1 g/min. AFM analysis of the deposited samples showed that the aggregation of gold nanoparticles is well controlled by the flow and deposition parameters.

Mass correlation spectroscopy for mass- and size-based nanoparticle characterization in fluid

The characterization of nanoparticles is an important problem in many areas of applied physics, chemistry, medicine, and biology. Micromechanical resonators with embedded fluidic channels represent a powerful new technology for particle characterization through direct measurement of the buoyant mass of nanoparticles in solution with attogram resolution (1 ag = 10−18 g). We recently showed that correlation analysis greatly expands the range of applications by enabling measurements of mass even when the individual particles are far lighter than the conventional detection limit. Here, we extend the concept of mass correlation spectroscopy further to simultaneously measure the ensemble-averaged size and mass of nanoparticles by exploiting size-dependent differences in hydrodynamic dispersion. To do so, we first derive an approximate model of the dispersion of finite-size particles flowing through a microfluidic channel of rectangular cross-section, valid in a large range of dispersion regimes. By including this solution into the model describing the correlation function of the time-domain mass signal acquired with a micromechanical resonator, information on particle size can be obtained during mass characterization without requiring any modification of the devices. The validity of the analysis is corroborated both by numerical simulations and experimental measurements on nanoparticles of different materials ranging from 15 nm to 500 nm.

Universal One-Pot and Scalable Synthesis of SERS Encoded Nanoparticles

Encoded particles are one of the most powerful approaches for multiplex high-throughput screening. Surface-enhanced Raman scattering (SERS) based codification can, in principle, avoid many of the intrinsic limitations due to conventional alternatives, as it decreases the reading time and particle size while allowing for almost unlimited codification. Unfortunately, methods for the synthetic preparation of these particles are tedious; often subjected to limited reproducibility (associated with large fluctuations in the size distributions of the polymers employed in the standard protocols); and to date, limited to a small amount of molecules. Herein, we report a universal, one-pot, inexpensive, and scalable synthetic protocol for the fabrication of SERS-encoded nanoparticles. This synthetic strategy is highly reproducible, independent of the chemical nature and size of the Raman code used (31 different codes were tested) and scalable in the liter range without affecting the final properties of the encoded structures. Furthermore, the SERS efficiency of the fabricated encoded nanoparticles is superior to that of the materials produced by conventional methods, while showing a remarkable reproducibility from batch to batch. This encoding strategy can easily be applied to nanoparticles of different materials and shapes.

Tumor Markers and Hepatocellular Carcinoma

survival rate of patients. Measurement of Alfa-Fetoprotein (AFP) in combination with iconography and liver biopsy are commonly used in the diagnosis of liver cancer as well as HCC. Despite the wide use of AFP in HCC diagnosis and introducing this tumor marker as the gold standard biomarker for HCC detection, the specificity and sensitivity of AFP used in screening for HCC is very controversial. In recent years, along with development of molecular biology and extensive research about ethnology of cancers and simultaneously advances in technology, researchers identified new tumor markers in this disease. In the latest researches various biomarkers including embryonic antigen, protein antigens, cytokines, enzymes and isoenzymes and related genes for effective early diagnosis and monitoring of hepatocellular carcinoma are introduced. In this review, a summary of the data of various studies that discuss new tumor markers involved in hepatocellular carcinoma and classification of these biomarkers was investigated Recently, use of different nanoparticle metal oxides for preventing the spread of microorganisms has reached to the expanding field of nanomaterial research. The objective of this study is to validate combined ultrasound and CuO or MgO noparticle treatments for inactivating Staphylococcus aureus and Pseudomonas aeruginosa. Results showed that nanoparticles of different materials vary in their effectiveness. Ultrasound increased the antibacterial effect of CuO nanoparticles more than the increased antibacterial effect of MgO. These results indicated that CuO or MgO nanoparticles exhibited antibacterial properties that could be additionally enhanced in the presence of ultrasound and, thus, should be further studied for a wide range of medical device anti-infection applications.