Effect of CuO and Graphene on PTFE Microfibers: Experimental and Modeling Approaches

The surface of pure polytetrafluoroethylene (PTFE) microfibers was modified with ZnO and graphene (G), and the composite was studied using ATR-FTIR, XRD, and FESEM. FTIR results showed that two significant bands appeared at 1556 cm−1 and 515 cm−1 as indications for CuO and G interaction. The SEM results indicated that CuO and G were distributed uniformly on the surface of the PTFE microfibers, confirming the production of the PTFE/CuO/G composite. Density functional theory (DFT) calculations were performed on PTFE polymer nanocomposites containing various metal oxides (MOs) such as MgO, Al2O3, SiO2, TiO2, Fe3O4, NiO, CuO, ZnO, and ZrO2 at the B3LYP level using the LAN2DZ basis set. Total dipole moment (TDM) and HOMO/LUMO bandgap energy ΔE both show that the physical and electrical characteristics of PTFE with OCu change to 76.136 Debye and 0.400 eV, respectively. PTFE/OCu was investigated to observe its interaction with graphene quantum dots (GQDs). The results show that PTFE/OCu/GQD ZTRI surface conductivity improved significantly. As a result, the TDM of PTFE/OCu/GQD ZTRI and the HOMO/LUMO bandgap energy ΔE were 39.124 Debye and ΔE 0.206 eV, respectively. The new electrical characteristics of PTFE/OCu/GQD ZTRI indicate that this surface is appropriate for electronic applications

Characterization of CdSe-nanocrystals used in semiconductors for aerospace applications: Production and optical properties

Semiconductor nanocrystals (NC’s) are the materials with dimensions less than 10 nm. When the dimensions of nanocrystals are reduced the bulk bohr diameter, the photo generated electron-hole pair becomes confined and nanocrystal exhibits size dependent upon optical properties. This work is focused on the studying of CdSe semiconductor nanocrystals. These nanocrystals are considered as one of the most widely studies semiconductors because of their size – tunable optical properties from the visible spectrum. CdSe-nanocrystals are produced and obtained throughout the experimental setup initiated at Nano-NRIAG Unit (NNU), which has been constructed and assembled at NRIAG institute. This unit has a specific characterization for preparing chemical compositions, which may be used for solar cell fabrications and space science technology. The materials prepared included cadmium oxide and selinid have sizes ranging between 2.27 nm and 3.75 nm. CdSe-nanocrystals are synthesized in “TOP/TOPO (tri–octyl phosphine/tri–octyl phosphine oxide). Diagnostic tools, include UV analysis, TEM microscope, and X-ray diffraction, which are considered for the analytical studies of the obtained materials. The results show that, in this size regime, the generated particles have unique optical properties, which is achieved from the UV analysis. Also, the TEM image analysis shows the size and shape of the produced particles. These studies are carried out to optimize the photoluminescent efficiency of these nanoparticles. Moreover, the data revealed that, the grain size of nanocrystals is dependent upon the growth time in turn, it leads to a change in the energy gap. Some applications of this class of materials are outlined

Satellite Laser

The paper concerns on the satellite laser ranging (SLR) in Egypt. The three generations which can be loosely defined by their single shot root mean square precision, are discussed. The laser generators used at the Helwan half automatic and full automatic stations are described. The equipments used for the operation of the satellite laser ranging and their upgrading are presented. The observations carried out from Helwan-SLR stations are mentioned. The importance of the satellite laser ranging from Egypt and their contributions to the SLR network are explained. The modification requested for increasing the performance of the Helwan-SLR station is given

The use of satellite laser observations in studying the crustal movements

The mutual tectonic displacements of the lithospheric blocks take place within the deep fracture dividing them into hundreds and thousands kilometers long. It is possible to suggest that the reason of the accumulation of considerable local shift deformations is the change of the velocity of the tectonic motion in some or other parts of fractures as a result of different physical, chemical and mechanical processes. Nowadays, the range precision of Satellite Laser Ranging (SLR) technique reaches a few millimeters level. Therefore, the space geodesy technique becomes a very important tool in detecting and monitoring recent crustal movements. Regular repeated measurements of the baselines between some stations on different plates give the possibility to construct precise and detail models of crustal movements. In this paper, the length of four baselines between Helwan-SLR station and other four SLR stations are calculated using satellite geodetical technique

Effect of CuO and Graphene on PTFE Microfibers: Experimental and Modeling Approaches

The surface of pure polytetrafluoroethylene (PTFE) microfibers was modified with ZnO and graphene (G), and the composite was studied using ATR-FTIR, XRD, and FESEM. FTIR results showed that two significant bands appeared at 1556 cm−1 and 515 cm−1 as indications for CuO and G interaction. The SEM results indicated that CuO and G were distributed uniformly on the surface of the PTFE microfibers, confirming the production of the PTFE/CuO/G composite. Density functional theory (DFT) calculations were performed on PTFE polymer nanocomposites containing various metal oxides (MOs) such as MgO, Al2O3, SiO2, TiO2, Fe3O4, NiO, CuO, ZnO, and ZrO2 at the B3LYP level using the LAN2DZ basis set. Total dipole moment (TDM) and HOMO/LUMO bandgap energy ΔE both show that the physical and electrical characteristics of PTFE with OCu change to 76.136 Debye and 0.400 eV, respectively. PTFE/OCu was investigated to observe its interaction with graphene quantum dots (GQDs). The results show that PTFE/OCu/GQD ZTRI surface conductivity improved significantly. As a result, the TDM of PTFE/OCu/GQD ZTRI and the HOMO/LUMO bandgap energy ΔE were 39.124 Debye and ΔE 0.206 eV, respectively. The new electrical characteristics of PTFE/OCu/GQD ZTRI indicate that this surface is appropriate for electronic applications