Large Scale Dynamic Molecular Modelling of Metal Oxide Nanoparticles in Engineering and Biological Fluids

Nanoparticles (NP) offer great merits over controlling thermal, chemical and physical properties when compared to their micro-sized counterparts. The effectiveness of the dispersion of the NP is the key aspect of the applications in nanotechnology. The project studies the characterization and modification of functional NPs aided by the means of large scale molecular thermal dynamic computerized dispersing simulations, in the level of Nanoclusters (NC). Carrying out NP functionality characterisation in fluids can be enhanced, and analysed through computational simulation based on their interactions with fluidic media; in terms of thermo-mechanical, dynamic, physical, chemical and rheological properties. From the engineering perspective, effective characterizations of the nanofluids have also been carried out based on the particles sizes and particle-fluids Brownian motion (BM) theory. The study covered firstly, investigation of the pure CuO NP diffusion in water and hydrocarbon fluids, secondly, examination of the modified CuO NP diffusion in water. In both cases the studies were put under experiments and simulations for data collection and comparison. For simulation the COMPASS forcefield, smoothed particle hydrodynamic potential (SPH) and discrete particle dynamics potential (DPD) were implemented through the system. Excellent prediction of BM, Van der Waals interaction, electrostatic interaction and a number of force-fields in the system were exploited. The experimental results trend demonstrated high coherence with the simulation results. At first the diffusion coefficient was found to be 1.7e-8m2/s in the study of CuO NC in water based fluidic system. Secondly highly concurrent simulation results (i.e. data for viscosity and thermal conductivity) have been computed to experimental coherence. The viscosity trend of MD simulation and experimental results show a high level of convergence for temperatures between 303-323K. The simulated thermal conductivity of the water-CuO nanofluid was between 0.6—0.75W•m−1•K−1, showing a slight increase following a rise in temperature from 303 to 323 K. Moreover, the alkane-CuO nanofluid experimental and simulated work was also carried out, for analysing the thermo-physical quantities. The alkane-CuO nanofluid viscosity was found 0.9—2.7mpas and thermal conductivity is between 0.1—0.4W•m−1•K−1. Finally, the successful modification of the NPs on experimental and simulation platform has been analysed using different characterization variables. Experimental modification data has been quantified by using Fourier Transformation Infrared (FTIR) peak response, from particular ranges of interest i.e. 1667-1609cm-1 and 1668-1557cm-1. These FTIR peaks deduced Carboxylate attachment on the surface of NPs. Later, MD simulation was approached to mimic experimental setup of modification chemistry and similar agglomerations were observed as during experimental conditions. However, this approach has not been presented before; therefore this study has a significant impact on describing the agglomeration of modified NPs on simulation and experimental basis. Henceforth, the methodology established for metal oxide nanoparticle dispersion simulation is a novelty of this work

Problems Faced While Simulating Nanofluids

Problems are faced when something is already been adopted for a considerable amount of time–here the problem that is discussed is related with nanofluids. The nanofluids have been considered for different engineering applications since last three decades; however, the work on its simulation has been started since last two decades. With the time, nanofluid simulations are increasing as compared to experimental testing. Researchers conducting nanofluid simulations do find difficulties and problems while trying to simulate this system. In addition to this, most of the time researchers are unaware of some basic problems and they find themselves stuck in relentless difficulties. Most of the time, these problems are very basic and can waste a lot of useful time of a research. Therefore, this chapter introduces some fundamental problems which a researcher can find while simulating nanofluids and with a simple way of dealing with it. Moreover, the chapter withholds lots of information regarding the way to design and to model a nanofluid system. Not only this, it also tends to elaborate the nanofluid simulation methodology in a precise manner. Moreover, the literature shows that nanofluid simulation has gained high consideration since last two decades, as experimental techniques are out of reach for everyone. In addition to experimental techniques, they are expensive, time-consuming and require high skills. However, it seems the simulation is picking pace with the due time and is considerably being adopted by the expertise dealing with nanofluids. This opens a high prospect of simulating nanofluids in future. Nevertheless, it seems there will be user-friendly software to conduct nanofluid simulations. Finally, issues and their resolution have also been conveyed which is the main aspect of this topic

Molecular dynamics simulation on surface modification of a quantum scaled CuO nano-clusters to support their experimental studies

© 2022 Springer Nature Limited. This article is licensed under a Creative Commons Attribution 4.0 International License, to view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.Interest in nanoparticle modification using functional chemicals has increased rapidly, as it is allowing more freedom of physiochemical tuning of the nanoparticle’s surfaces into biomedically oriented and designated properties. However, the observation and detection of the thin molecular layers on the nanoparticle surface are very challenging under current analytical facilities. The focus of this research is to demonstrate fundamental interactions between the surface treated nanoparticles and their host liquid media using lab-based experimentation and simulation. In this research, investigation has been carried out on analyzing the surface compatibility and the diffusivity of modified CuO nanoparticles with short-chain carboxylate-terminated molecules in biofluids. Moreover, during the current Covid-19 pandemic, the Cu/CuONPs have proved effective in killing SARS-CoV1/2 and other airborne viruses. This research was conducted at the molecular level with joint consideration of experimental and simulation studies for characterization of variables. Experimental tests conducted using Fourier Transmission Infrared (FTIR) demonstrated several ranges of interest from FTIR responses, specifically, detection of three major carboxylate attachments (i.e., 1667 cm-1 -1609 cm-1, 1668 cm-1 - 1557 cm-1, etc.) were found. From simulation, similar attachment styles were observed by the LAMMPS simulation package that mimicked similar agglomerations with a predicted diffusion coefficient as recorded to be 2.28E-9m2/s. Viscosities of modified nanofluids were also compared with unmodified nanofluids for defining aggregation kinetics.Peer reviewe

Development of the Flight Dynamic Model (FDM) Using Computational Fluid Dynamic (CFD) Simulations for an Unknown Aircraft

The usage of computational fluid dynamics (CFD) has enhanced 10-fold since the last decade, especially in the area of aerospace science. In this chapter, we will focus on determining the feasibility and validity of CFD results that are plugged in flight dynamic model (FDM) to that of actual flight of an aircraft. Flight data of an actual aircraft is used to determine the aerodynamic performance of the designed FDM. In addition to this, FDM consist of various systems integration of an aircraft; however, this study will focus on aerodynamic parameter optimization. Relative analysis is carried out to validate the FDM. This will enable readers to know how CFD can be a great tool for designing FDM of an unknown aircraft

31st Annual Meeting and Associated Programs of the Society for Immunotherapy of Cancer (SITC 2016) : part two

Background The immunological escape of tumors represents one of the main ob- stacles to the treatment of malignancies. The blockade of PD-1 or CTLA-4 receptors represented a milestone in the history of immunotherapy. However, immune checkpoint inhibitors seem to be effective in specific cohorts of patients. It has been proposed that their efficacy relies on the presence of an immunological response. Thus, we hypothesized that disruption of the PD-L1/PD-1 axis would synergize with our oncolytic vaccine platform PeptiCRAd. Methods We used murine B16OVA in vivo tumor models and flow cytometry analysis to investigate the immunological background. Results First, we found that high-burden B16OVA tumors were refractory to combination immunotherapy. However, with a more aggressive schedule, tumors with a lower burden were more susceptible to the combination of PeptiCRAd and PD-L1 blockade. The therapy signifi- cantly increased the median survival of mice (Fig. 7). Interestingly, the reduced growth of contralaterally injected B16F10 cells sug- gested the presence of a long lasting immunological memory also against non-targeted antigens. Concerning the functional state of tumor infiltrating lymphocytes (TILs), we found that all the immune therapies would enhance the percentage of activated (PD-1pos TIM- 3neg) T lymphocytes and reduce the amount of exhausted (PD-1pos TIM-3pos) cells compared to placebo. As expected, we found that PeptiCRAd monotherapy could increase the number of antigen spe- cific CD8+ T cells compared to other treatments. However, only the combination with PD-L1 blockade could significantly increase the ra- tio between activated and exhausted pentamer positive cells (p= 0.0058), suggesting that by disrupting the PD-1/PD-L1 axis we could decrease the amount of dysfunctional antigen specific T cells. We ob- served that the anatomical location deeply influenced the state of CD4+ and CD8+ T lymphocytes. In fact, TIM-3 expression was in- creased by 2 fold on TILs compared to splenic and lymphoid T cells. In the CD8+ compartment, the expression of PD-1 on the surface seemed to be restricted to the tumor micro-environment, while CD4 + T cells had a high expression of PD-1 also in lymphoid organs. Interestingly, we found that the levels of PD-1 were significantly higher on CD8+ T cells than on CD4+ T cells into the tumor micro- environment (p < 0.0001). Conclusions In conclusion, we demonstrated that the efficacy of immune check- point inhibitors might be strongly enhanced by their combination with cancer vaccines. PeptiCRAd was able to increase the number of antigen-specific T cells and PD-L1 blockade prevented their exhaus- tion, resulting in long-lasting immunological memory and increased median survival

The preparation and tribological properties of surface modified zinc borate ultrafine powder as a lubricant additive in liquid paraffin

This paper investigates the effects of surface modification of zinc borate ultrafine powders (ZB UFPs) on their tribological properties as lubricant additives in liquid paraffin (LP). ZB UFPs were successfully modified by hexadecyltrimethoxysilane (HDTMOS) and oleic acid (OA). It is evident that HDTMOS modified zinc borate ultrafine powder (HDTMOS-ZB UFP) delivered a small conglomerate size, good stability in the organic solvent and sound anti-wear property. It has been observed that a continuous and tenacious tribo-film on the worn surface generated from HDTMOS modified ZB UFP as a lubricant additive in LP plays an important role in the outstanding anti-wear property. It is suggested that HDTMOS modified ZB UFP as a lubricant additive in LP has a great potential.Peer reviewedSubmitted Versio

Comparative molecular dynamics simulations of thermal conductivities of aqueous and hydrocarbon nanofluids

© 2022 Loya et al.; licensee Beilstein-Institut. This is an open access article licensed under the terms of the Beilstein-Institut Open Access License Agreement, which is identical to the Creative Commons Attribution 4.0 International License (https://creativecommons.org/licenses/by/4.0).The addition of metal oxide nanoparticles to fluids has been used as a means of enhancing the thermal conductive properties of base fluids. This method formulates a heterogeneous fluid conferred by nanoparticles and can be used for high-end fluid heat-transfer applications, such as phase-change materials and fluids for internal combustion engines. These nanoparticles can enhance the properties of both polar and nonpolar fluids. In the current paper, dispersions of nanoparticles were carried out in hydrocarbon and aqueous-based fluids using molecular dynamic simulations (MDS). The MDS results have been validated using the autocorrelation function and previous experimental data. Highly concurrent trends were achieved for the obtained results. According to the obtained results of MDS, adding CuO nanoparticles increased the thermal conductivity of water by 25% (from 0.6 to 0.75 W·m-1·K−1). However, by adding these nanoparticles to hydrocarbon-based fluids (i.e., alkane) the thermal conductivity was increased three times (from 0.1 to 0.4 W·m−1·K−1). This approach to determine the thermal conductivity of metal oxide nanoparticles in aqueous and nonaqueous fluids using visual molecular dynamics and interactive autocorrelations demonstrate a great tool to quantify thermophysical properties of nanofluids using a simulation environment. Moreover, this comparison introduces data on aqueous and nonaqueous suspensions in one study.Peer reviewe

A molecular dynamic investigation of viscosity and diffusion coefficient of nanoclusters in hydrocarbon fluids

Date of Acceptance: 23/11/2014Straight chain alkanes modified by metal oxide nanoclusters have gained wide recognition in applications in tribology, energy and thermal storage. This paper investigates the system’s rheological properties and diffusion coefficient in a reflection of the nanocluster’s nanofluidic dispersibility and stability in the domain of thermal and diffusive properties. A computational model working on CuO nanoclusters in an alkane (C20H44) fluidic system has been developed at an atomic-molecular level. The simulation results are used to assess the outcomes of the suspension’s fluidic stability and thermal diffusive capabilities. A COMPASS force field was employed, and periodic boundary conditions were defined to address the molecular dynamic (MD) simulation results in the dispersion system. The MD viscosity quantification using stress autocorrelation function shows a monotonic decay for 303–323 K temperatures. These results of autocorrelation calculations were used for validating viscosity results obtained from MD simulation. The viscosity of the CuO-Alkane system was found out to be 1.613 mPa s at 303 K. The diffusion coefficients were also calculated for the CuO-Alkane system using mean square displacement and it was found that at 303 K this system gives 4.302 E−11 m2/s rate of diffusionPeer reviewe

Determination of Cu2+ ions release rate from antimicrobial copper bearing stainless steel by joint analysis using ICP-OES and XPS

Antibacterial Cu bearing stainless steels (CuSS) have been developed recently and their performance has attracted significant attention widely in biomedical, healthcare and environmental facilities in cross-disciplines. The antibacterial ability and its efficiency of the CuSS are associated to the rate and concentration of Cu2z ions releases from its surface. The surface properties such as corrosion resistance are also influenced by the amount and the rate of Cu ions released. Thus, the aim of this study focused on the determination of trace release amount of Cu2+ ions from a typical copper bearing 304 stainless steel (304CuSS). Meanwhile, the release of other key elements in the material such as Cr, Fe, Ni were also examined, and found these multiple elemental releases produced a highly synergistic effect on killing bacterium. The release rate of the metals from 304CuSS was conducted by an inductively coupled plasma optical emission spectrometry (ICP-OES). In this study, the commercial 304 stainless steel (304SS) was served as a control material, while the ICP results showed that the Cu2z ions released from 304CuSS were maintained a constant level with a release rate as low as 0?8 ppb/day/cm2. This phenomenon could be explained by a coordinating role or synergistic effects of Cu, Fe, Cr, and Ni ions. XPS surface composition analysis showed a releases contribution results in day 1 and day 14 that the reduction trend of Cu quantities in through of the surface depth of 304CuSS is consistent and comprehensible.Peer reviewe