فصلنامه دنیای نانو
پیاپی 71 (تابستان 1402)

The advances achieved in nanotechnology have brought significant changes in the coating and formulating processes, which have created practical applications in dealing with fire, corrosion, impact, heat, wear, wear and tear and other environmental factors. In this context, it is possible to control indicators such as size, chemical properties, surface protection, activity, and reactivity of nanoparticles. The application of nanocoatings in steel structures in light and heavy industries and marine is determined according to their specific design and the properties resulting from this structure. The aim of the present research work is to prepare epoxy nano-coatings based on graphene composite to prevent the corrosion of steel. Graphene oxide was first synthesized by the modified Hamer method to prepare these compounds. Then, by using iron, nickel and cobalt metals, the desired composite was prepared and identified using FTIR, FESEM, XRD, EDX, TGA and DSC analyses. TOEFL curves were used to check and evaluate the resistance of the prepared coating and its components against corrosion.

The utilization of solar energy as the cleanest and most abundant source of energy available, as an environmentally friendly solution, is proposed to overcome the global problem of lack of potable water. It is common to use photothermal materials to harvest and store solar energy in steam production systems. These materials are classified into three main groups, including carbon-based materials, plasmonic metals, and semiconductors. Among them, the use of carbon nanomaterials has been greatly welcomed by researchers. this attention is due to its appropriate features such as high absorption level, abundance, reasonable price, and availability in nature. In this article, by introducing solar steam production systems (SSG), the characteristics and mechanism of light absorption in photothermal materials are discussed. This paper is focusing on the carbon nanomaterials, especially graphene as an attractive two-dimensional nanostructure with unique optical properties. In the following, some of the research conducted in this field are briefly reviewed.

The depletion of non-renewable energies for the future generations and the increasing temperature of the earth have forced researchers to investigate the alternatives of these energies. A lot of energy wastage in the devices used today led scientists to turn these energies into useful energies. The results of the research show that thermoelectric materials, which are a type of solid state energy converters with a combination of thermal electrical and semiconducting properties that lead to the conversion of waste thermal energy into electricity, can be a suitable alternative according to the definitions. Two-dimensional materials have attracted the attention of many researchers due to their unique features such as a very high specific surface. A group of two-dimensional materials that have been discovered are mxenes. Mxenes are a new range of materials obtained by using Max phases. These materials usually have a metal element from intermediate metals, generally titanium or chromium, along with carbon or nitrogen and a functional group such as fluorine, oxygen or hydroxide. According to Altenkirch's theory, the quality of thermoelectric materials is determined by coefficients of Seebeck and thermal conductivity. In this work, Boltzmann's semi-classical transport theory has been used in the form of "Boltztrap" software package to calculate transport coefficients. In many cases, this theory has answers that agree very well with experimental results. "Quantum Espresso" software package has been used to check the structural properties of titanium carbide and to use it in the input files of Boltz Trap code.

The global rise in cancer cases highlights the need for effective therapeutic strategies that not only reduce side effects but also enhance performance and efficacy. Conventional treatments such as medical methods, radiation therapy, and chemotherapy have limitations and safety concerns. To address these issues, drug delivery systems (DDSs) or nano drug delivery systems( NDDSs) have been proposed to release drugs specifically on cancer cells while sparing normal tissue. pH-responsive systems have been developed to improve the selectivity of anticancer drugs by taking advantage of the lower pH of tumor sites. This approach minimizes side effects and overdosage and is made possible by enhanced permeability and retention (EPR), which increases drug accumulation at tumor sites. Particle size is a crucial factor in nanocarriers containing anticancer drugs, and in this study, for the first time, the particle size of nanocarriers (nano systems)was analyzed using electron microscopy to improve the release of anticancer drugs.

Hydrogen has the potential to be a promising clean energy source to replace non-renewable fossil fuels. The inability to store hydrogen effectively and safety concerns are what prevent it from being used as a substitute fuel. Current hydrogen capture systems, such as small and liquid storage, are too expensive for use in practical applications. Metal-organic frameworks (MOFs) are crystalline substances with a huge surface area, a high porosity, and excellent hydrogen absorption. The physiological adsorption of hydrogen in MOFs is brought on by a weak van der Waals attractive attraction, which is easily reversible with the right amount of heat or pressure. It has been looked at how to improve the surface area, as well as the ability of MOFs to absorb hydrogen.The hydrogen overflow mechanism has been shown to offer high-density storage in comparison to other systems. In order to turn hydrogen that has been stored into energy, MOFs can be utilized as proton exchange membranes and electrodes for fuel cells. Because MOFs have a low conductivity, doping allows for their use in fuel cells. Thus, by converting carbon into fuel cells, this eco-friendly technology can aid in reducing carbon in industrial settings. Additionally, the capacity of hydrogen to be absorbed as a fuel for hydrogen cars must fall within the range (100 bar or less). The primary methods that could improve hydrogen storage for using hydrogen as a fuel were covered in this study, along with the possibility for further advancement to satisfy future energy demands.

Cancer is one of the current, widespread diseases in the world which human beings have tackled over the years. In this study the whole process of hyperthermia was simulated in the “COMSOL” software. The octane base fluid and 〖Fe〗_3 O_4 nanomagnetic particles were used in the simulations. The infusion of nanofluid into the porous medium, nanofluid diffusion in tumor, and production of heat caused by nanomagnetic particles were included. For the selected geometry and by using the fine grid, the nanofluid pressure and concentration as function of time were calculated. The results showed that all the physics were involved and were correctly implemented in the Comsol software. Also, the effect of the magnetic field intensity and it’s frequency, concentration and diameter of the nanoparticles on the temperature distribution inside the tumor has been investigated. The calculations showed that by increasing the magnetic field intensity from 1.2 kA/m to 1.4 kA/m, frequency from 164kHz to 180kHz, concentration of nanoparticles from 1024.29 mol/m3 to 1200 mol/m3 and nanoparticles diameter from 8nm to 11nm the tumoral tissue temperature increased from 48℃ to 54℃, 48℃ to 65℃, 48℃ to 80℃ and 48℃ to 160℃ respectively. The mentioned parameters have a direct effect on the generated heat inside the tumor, but it should be noted that increasing the temperature up to 48 ℃ is suitable and temperatures more than 48 ℃ causes damage in the healthy tissues around the tumor.