Materials Science Forum Vol. 856

Abstract: A family of consistent thin-wire representation models blended with a 3-D optimized vector finite-element time-domain/finite-difference time-domain method is developed in this paper for nanomaterial and graphene devices. Based on a tailored set of telegrapher’s equations, the novel technique approximates traveling waves along the radial direction of the wire and minimizes artificial instabilities. Also, through a non-overlapping grid discretization algorithm, the hyperbolic character of Maxwell’s laws is physically preserved. In this way, tilted or circular-loop structures of arbitrary orientation are accurately coupled with the curvilinear algorithm. These attributes are successfully verified via various nanoscale components and finite-sized graphene arrangements.

Abstract: We present non-equilibrium molecular dynamic simulations of
the shock compression of polyurethane and its graphene-based nanocomposite systems. Using the projectile/wall approach, planar shock waves with piston velocity range from 0.1 to 2.5 km/s is applied for both systems. In this study, direct molecular-level simulations of shock-wave generation and propagation are utilized in order to construct the appropriate shock-Hugoniot relations. Through this study, we determined that inclusion of graphene into the polyurethane system has a significant effect on the shock propagation behavior when incorporated in the polymer matrix

Abstract: Thermal expansion of anti-parallel beta pleated sheets with Bombyx mori silk nanostructures [Gly-Ser-Gly-Ala-Gly-Ala]_n and commonly used model of [Gly-Ala]_n have been investigated through molecular dynamics (MD) simulation calculations in conjunction with interatomic interactions modeled by CHARMM force field method between the temperature range of 300K-700K. Preliminary results indicate significant differences on thermal expansion of two structures that was observed on directions of chain and the direction perpendicular to plates.

Abstract: The present study aims to investigate temperature dependence of anisotropic mechanical properties of anti-parallel beta pleated sheets with Bombyx mori silk nanostructures in sequence of [Gly-Ser-Gly-Ala-Gly-Ala]_n and commonly used model in sequence of [Gly-Ala]_n. Classical molecular dynamics simulation method was used to carry out calculations, preliminary, at 300K. Ionic interactions were modeled by CHARMM force field method. Substitution of Ala with Ser residue results with a gradual conformational change in the stress-strain.

Abstract: A predictive microscale-informed model that takes into account the precipitate–shape memory performance relations and allows for the evaluation of the effective thermomechanical response of precipitated Ni-rich NiTi shape memory alloys on the basis of composition and heat treatment is presented. The model considers the structural effect of the precipitates (coherency stresses due to the lattice mismatch between the precipitates and the matrix material and precipitate volume fraction), as well as the effect of the Ni-concentration gradient in the matrix, resulting from Ni-depletion during precipitate growth. The predictive capability of the model is tested against experimental data obtained fromNi₅₀.₇Ti (at. %) that has been heat treated under different conditions and good agreement is shown.

Abstract: In this paper we present a new method for the monitoring of super-paramagnetic nanoparticles (SPANs) in the body. Nowadays, reliable and inexpensive device and method for monitoring the spatial distribution of SPANs in the body are not present in the market of clinical imaging equipments. Importantly, since SPANs can be conjugated to a huge variety of organic (antibodies, proteins, synthetic polymers) and inorganic molecules they can be used to selectively detect targets (e.g. cancer cells) with striking specificity. The existing imaging methods used for clinical diagnostic purposes are the nuclear magnetic resonance (NMR) and computerized axial tomography scan (CAT or CT scan). Detection of SPANs with these methods is still controversial and most import they used strong magnetic field and harmful X-ray radiation, respectively, and the cost for a single analysis is high as well. Herein we describe an innovative magnetic method promises the measurement of the distribution of SPANs with sensitivity quite better than 1 μm³. The method (patented device by our group) is based on magnetic excitation and consequent detection of nanoparticles using super-conducting or magnetic sensors (magnetometers). The device is innovative and novel, and could be considered as a universal breakthrough in tumor diagnosis. Possible other applications could be simultaneous killing of the cancer cells applying inductive heating techniques.

Abstract: An actual problem is the synthesis of ceramic composite materials based on refractory compounds to produce nanostructured materials with high mechanical strength, namely, flexural strength, fracture toughness, hardness, heat resistance and thermal strength. Of particular interest is the transformational-reinforced ceramic, which is not inferior in strength characteristics of conventional structural alloys. Particularly noteworthy are composites based on the composition ZrO₂ / Al₂O₃, which have high strength and toughness in comparison with monozirconium or monocorundum ceramics.

Abstract: In this work, we report the preparation of MFNCs integrating MnFe₂O₄ magnetic nanoparticles (MNPs), near infrared CuInS₂/ZnS quantum dots (QDs) and poly (ethylene glycol)-b-poly (lactide-co-glycolide) (PEG-PLGA) in a tetrahydrofuran (THF)/water solvent system. It is found that the MFNCs possess high (Mn + Fe) recovery rates, and the optical properties and magnetic relaxivity of the MFNCs are tunable according to the MNP:QD mass ratios. Furthermore, the MFNCs present excellent capability for tumor cell targeting once they are conjugated with bioprobes specific to tumor cells. This study opens an avenue for the MFNCs to be employed in broad biological or biomedical applications.

Abstract: The aim of this study is to describe the synthetic procedure of superparamagnetic nanoparticles of magnetite and maghemite and to use the magnetic merit of thesenano-sized ferrite particles coated byorganic substances having good water solubility to desalinate saline water. The idea derives from the experimental results of research groups using magnetic particles covered by polymers to increase the efficiency of membranes in forward osmosis desalination plants. The magnetic particles can beseparatedfrom water by an external magnet field easily.As magnetic particles, Fe₃O₄ can be prepared in different sizes from nanoto microscale by the help of co-precipitation or thermal decomposition techniques. These superparamagnetic nanoparticles are well-promising candidates for use in desalination purposes either from own or after their fabrication with polymer molecules, such as cyclodexrins, in their original form or in a modified one in order to enhance their water solubility, according to some preliminary experimental results found by our research team but not referred here. Herein, various inexpensive synthetic routes for superparamagnetic nanoparticles of magnetite (Fe₃O₄) and maghemite ( -Fe₂O₃) are described, as well as the characterization results of the produced nanoparticles with XRD, TEM, FT-IR, RAMAN, DFT and TGA/DTG analytical techniques are also referred.

Abstract: In this paper the important impact of high temperature withstand on performance of electromagnetic actuators for aerospace applications is illustrated. Particular materials enabling high performance and increased reliability in such applications are analysed both through numerical simulations and experimental validation. Specific examples outline advancements in electrical machine technologies for this class of problems.