One of the most important issues in today’s world involves supplying energy through renewable materials using synthetic methods and no use of fossil fuels. In recent years, significant attention has been paid to biodiesel fuel, which produces low environmental pollution and is compatible with diesel engines. However, various parameters must be considered in its production, including reaction time, type of catalyst, solvent, feed or raw materials, alcohol:oil molar ratio, cost of production, method and catalyst recycling process. This study investigates the efficiency of various catalysts such as nano-catalysts that have been used in recent years and compares their advantages and disadvantages. The results and data obtained from previous studies indicate that the type of catalyst may be determined with regard to high contact surface, easy separability, low preparation time, low cost incurred and the raw material used in this process. The raw materials in question can be animal oil, vegetable oil or burnt and recycled oil.

A Quantum Mechanics (QM) is used for investigated the nature of metals transport and interaction with single-walled carbon nanotubes (SWCNTs) inter membranes. Metal species can be transported actively by a combination of SWCNT-membranes conducting channels that have been used for bio-molecular and detection. This study is based on the interaction of Na, Mg, Al, and Si with the structural features of SWCNTs in the ground state ab initio, HF theory and DFT calculation have been performed with the program Gaussian A7 package suite of programs. We used HF and DFT (B3LYP) method for calculation energy, chemical shift nucleus magnetic resonance and proportion thermodynamic by DFT-IR and DFT-NMR for RWCNT in absence and presence metals. The basis set used 6-31G and 6-31G* that increasing electronegativity metals increased the total energy. The proportion SWCNTs were changed by them. In this study presented a comprehensive on effects of metals on SWCNTs, which are on theirs electronic structure, and transfer of charge from metal to SWCNTs. The results are presented for T = 310 K, the temperature of human’s body.

The application of graphene-based nanocomposites for therapeutic and diagnostic reasons has advanced considerably in recent years due to advancements in the synthesis and design of graphene-based nanocomposites, giving rise to a new field of nano-cancer diagnosis and treatment. Nano-graphene is being utilized more often in the field of cancer therapy, where it is employed in conjunction with diagnostics and treatment to address the complex clinical obstacles and problems associated with this life-threatening illness. When compared to other nanomaterials, graphene derivatives stand out due to their remarkable structural, mechanical, electrical, optical, and thermal capabilities. The high specific surface area of these materials makes them useful as carriers in controlled release systems that respond to external stimuli; these compounds include drugs and biomolecules like nucleic acid sequences (DNA and RNA). Furthermore, the presence of distinctive sheet-like nanostructures and the capacity for photothermal conversion have rendered graphene-based nanocomposites highly favorable for optical therapeutic applications, including photothermal treatment (PTT), photodynamic therapy (PDT), and theranostics. This review highlights the current state and benefits of using graphene-based nanocomposites in cancer diagnosis and therapy and discusses the obstacles and prospects of their future development. Then we focus on graphene-based nanocomposites applications in cancer treatment, including smart drug delivery systems, PTT, and PDT. Lastly, the biocompatibility of graphene-based nanocomposites is also discussed to provide a unique overview of the topic.

The nanocrystalline silicon-germanium films (Si/Ge) and Si/Ge nanotubes have low band gaps and high carrier mobility, thus offering appealing potential for absorbing gas molecules. Interaction between hydrogen molecules and bare as well as functionalized Si/Ge nanofilm and nanotube was investigated using Monte Carlo (MC) and Langevin dynamic (LD) simulation methods. It was found that the binding energy of the H₂ on the Si/Ge surface is weak, and be enhanced by increasing curvature of surface to tube form and increasing temperature. The structural, total energy and energy band gaps of H₂ absorbed nanocrystalline silicon germanium film (Si/Ge) and as it passes through Si/Ge nanotube was also studied. They are computed with MC and LD simulation the methods at different temperatures. All the calculations were carried out using HyperChem 7.0 program package. KEY WORDS: Monte Carlo, Langevin dynamic simulation, Silicon-germanium films (Si/Ge), Si/Ge nanotube Bull. Chem. Soc. Ethiop. 2008, 22(2), 277-286.

This work presents a study of the adsorption properties of nanostructures. The moving gas technique was employed to determine the transient and steady-state response behavior of nanocrystalline gas sensors. SnO2 sensors have shown high sensitivity to low concentrations of ethanol at moderate temperature. Tin dioxide is the most used material for gas sensing because its three-dimensional nanofilms and properties are related to the large surface exposed to gas adsorption. This study proposes the use of SnO2 nanofilms in interaction with ethanol; we used different percentages of SnO2 and WO3 in the adsorption of ethanol by nanofilms. The total energy, potential energy, and kinetic energy were calculated for the interaction between nanofilms and ethanol at different concentrations and at 300 K. The calculations were achieved by Langevin dynamics and Monte Carlo simulation methods. The total energy decreased with additional tungsten percentage in the nanofilms and increased with additional number of ethanol molecules and interactions between them are endothermic.