The work we present here is intended as a contribution to the study of the thermodynamic properties of zircon. For this purpose, we have implemented the quasi-harmonic Debye model, in which the vibrations of the network of atoms are taken into account. This study has a dual objective, first to calculate the thermodynamic quantities of zircon for different temperatures and to test the validity of the model with the data available in the literature. In addition, due to the structural complexity of the zircon equation of state, we have developed a Matlab code in deterministic mode to perform the calculations. At the end of the study, the results obtained are consistent and meaningful. Overall, the results indicate that heat capacity, internal energy and entropy increase with temperature. This growth is more marked with the internal energy than with the entropy and the thermal capacity which tends towards the limit value of Dulong-Petit. In addition, the results of our simulations are in excellent agreement with others reported in the literature. These studies clearly demonstrate that zircon can be categorized as hard materials due to their high Debye temperature. We hope that this study could stimulate experimental studies about zircon (ZrSiO4) characterization in Senegal.
Despite the wide application of nanoparticles (NPs), there is a serious lack of information concerning their impact on human health and the environment. In fact, nano-materials are the leading edge of nanotechnology and their unique size-dependent properties make these materials superior and indispensable in many areas of human activity. Zinc oxide nanoparticles were produced synthetically by wet chemical route by using cheap precursors. The size of the particles were determined by X-ray Diffraction (XRD) and scanning electron microscopy (SEM) and was compared to that of bulk ZnO. structure and size Further studies were carried out to determine the difference in electrical properties (dielectric constant, dissipation factor, A.C. conductivity, resistivity) of these materials due to their size difference. Similar variations occurred in the liver enzymes; ALT, AST, as a result of treated the rats with ZnO in the bulk and Nano-forms. The increase in these enzymes indicated liver damage toxicity.
Tin oxide coated zinc oxide nanorod arrays (SnO2/ZnO) were prepared using two step sol-gel processes in which the ZnO nanorod arrays were initially grown on ZnO seed layer coated glass substrate. Then, a thin layer of SnO2 is coated on the nanorod arrays using spin coating method. The structural and optical properties of the films were investigated using FESEM, XRD and UV-vis, respectively. The surface morphology of the films showed that the nanorod arrays are covered by rough layer of SnO2. The average diameter of ZnO nanorods is about 80 nm. The XRD plot indicates that the film consist of hexagonal wurtzite ZnO and rutile SnO2 structure. Besides, the addition of SnO2 layer leads to diffraction angle shifting at (002) plane orientation. The optical properties of films displayed that the SnO2/ZnO induced lower transmittance film at visible region than that of bare ZnO nanorod arrays. Besides, the SnO2/ZnO film exhibited high optical band gap energy of 3.35 eV.
A natural rubber containing carbon nanotubes and carbonyl iron powder was prepared by a conventional technique using a two roll mill. The magnetic field version magnetization was conducted to study the magnetic characteristics of magnetorheological nanocomposites material (MNM) samples. This magnetic measurement is the induction method of scanning magnetic flux induced by the magnetic vibrating sample. The corresponding hysteresis graphs of MNE was plotted and the magnetization for was observed. The microstructure of the magnetic rubber was characterized by field emission scanning electron microscopy (FESEM). Results revealed that the Iron particles were relatively well dispersed in an NR matrix. It was found that the sample without CNT and iron powder dispersed magnetic rubber showed lower magnetization and retentively than the other.
The synthesis of graphene by double thermal chemical vapor deposition using waste cooking palm oil (WCPO) as a natural carbon source was investigated. The WCPO was placed in the first furnace (precursor furnace) and nickel was placed in the second furnace (deposition furnace). The deposition temperatures were varied from 850 °C to 1100 °C by 50 °C increments. The formation of the graphene on the Ni surface appears due to segregation and precipitation of high amount of carbon from the source material during the cooling process. It was found that raising the deposition temperatures was lead to the changed of shapes and different densities of the samples. FESEM images at optimum temperature (1000 °C) display hexagonal shapes since the graphene layers were formed after precipitation of the carbon. Furthermore, XRD analysis was employed to distinguish the presence of graphene on Ni substrate. Meanwhile, the interlayer distance, number of layers, crystalline size and impurity composition were compared by simple XRD pattern. At an optimum deposition temperature, the Raman result shows that the I2D/IG ratio (0.36), which indicates that sample is multi-layer graphene.
Ultraviolet (UV) photoconductive sensor were fabricated based on aluminum (Al) doped zinc oxide (ZnO) nanorod arrays at different doping concentrations varied from 0 at.% (undoped) to 2 at.% which were deposited on glass substrates using immersion method. The average diameter of nanorods decreased with increased of Al doping concentration. The transmittance of all samples is above 70% in the visible regions. The electrical properties were improved by dopant concentrations as shown by I-V measurement results. UV responsivity and sensitivity of 0.8 at.% Al doping concentration is the highest compared to other samples with value of 8.81 A/W and 51.67, respectively.
Light emitting diode (LED) is solid state lighting uses semiconductor material and convert the electrical energy to light energy. Titanium dioxide (TiO2) was used in optoelectronic devices because it is good purity and easily synthesizing onto thin film. TiO2 nanotubes was prepared by electrochemical anodization method at room temperature. The TiO2 nanotubes was investigated amorphous and annealed sample at 450°C. The surface morphology revealed that sample annealed at 450°C showed uniformity with a regular porous on top layer of TiO2. Raman pattern showed the amorphous-to-crystalline anodic TiO2 sample transition with anodization. Optical properties showed the TiO2 nanotubes annealed at 450°C has not sharp absorbance edge and it is relates to the oxygen deficiency in nanotube material. The TiO2 nanotubes film annealed at 450°C has potential apply to LED devices.
Organic semiconductor have been discovered in different application devices such as organic light emitting diodes (OLEDs). Poly [2-methoxy-5(2’ –ethylhexyloxy)-1, 4-phenylenevinylene), MEH-PPV used in optoelectronic devices because it is easily synthesizing and deposit in high molecular weight and good purity. The evaporating temperature at 750°C with 5 sccm flow of ZnO, the weight of 5 mg/ml and temperature at 50°C were chosen to fabricate MEH-PPV: ZnO nanocomposites on the optimal properties. MEH-PPV: ZnO nanocomposites was prepared by spin coating technique at room temperature. MEH-PPV: ZnO nanocomposites thin film was investigated at pure MEH-PPV (0 wt%) and 0.2 wt% of ZnO. The surface morphology revealed that 0.2 wt% of ZnO showed uniformity and less aggregation compared to MEH-PPV thin film. The electrical properties showed that the ZnO composition at 0.2 wt% exhibits the highest conductivity of 7.40 x 10−1 S. cm-1 compared to polymer thin film this value suitable applied in optoelectronic devices.
TiO2:ZNR thin films have been fabricated on glass substrates via sol-gel spin-coating technique and solution-immersion method, respectively. Zinc oxide nanorods (ZNR) were grown at low temperature of 90°C for 2,3,4,5 and 6 hours of immersion time on titanium dioxide (TiO2) seed layer-coated substrate. FESEM images showed that the densest distributions of ZNR with smaller diameter size were observed around 3 and 4 h. The diffraction peaks of (0 0 2)-plane were observed for all thin films, indicating nanorods orientation in the c-axis direction as detected in XRD patterns. UV-Vis absorbance spectra recorded that smaller size of ZNR at 3 and 4 h have maximum intensity of UV absorption properties.
In this work, zinc oxide (ZnO) nanostructures prepared by immersion method with zinc nitrate hexahydrate (Zn(NO3)2.6H2O) as a precursor were successfully grown on TiO2 seed layer with three different stabilizers i.e. hexamethylenetetramine, C6H12N4 (HMTA), urea (CH4N2O) and sodium hydroxide (NaOH). The effect of various stabilizers on the size particles, surface morphologies and element composition in grown ZnO were investigated by using ZETA nanoparticle sizer, FESEM and EDX. Size particles of ZnO solutions after immersion method was observed and the smallest particles sizes were recorded for HMTA. FESEM images showed that ZnO nanorods, nanoflowers and grain-like structures were formed when using HMTA, urea and NaOH as stabilizer. The presence of ZnO and TiO2 were confirmed by EDX analysis by showing that all samples that used stabilizer have highest weight % of Zn element.
Polystyrene/Silica Nanocomposites (PS/Si NCs) are attractive material due to their stability (chemical and thermal), low toxicity, the probability from controlling their particle size, ability to be functionalized with a range of molecules and polymers, biocompatibility, degradability below physiographic statuses and low-cost production of materials. In that paper now, The procedure to fabricate polystyrene/silica (PS/SiO2) hybrid hollow spheres did successfully combine by precipitation technique, which was then used to react with silica nanoparticles that were prepared by the sol-gel method to fabricate PS/SiO2 nanocomposite. Four Point Probe, Transition electron microscopy (TEM), and XRD are used to analyze the physical, chemical, optical properties and electric of polystyrene/SiO2 nanocomposites. The experimental effects indicate the possibilities for PS/SiO2 to be used as biomaterials, coating and catalyst materials.
Graphene successfully formed on the Ni surface due to segregation and precipitation of high amount of carbon originated from the source material occurred at cooling process. The growth of graphene at different cycles of refined cooking palm oil using double thermal chemical vapour deposition method (DTCVD) was investigated. The samples were prepared at different cycles of refined cooking palm oil, which is unused (refined), first cycle, second cycles and third cycles at vaporization temperature of 350 °C and the temperature of Ni substrate constant at 900 °C. Comparison of the Fesem results indicated that the difference of cycles refined cooking palm oil has significant structural changes. Third cycles of refined cooking palm oil as precursor shown the graphene grain seems to growth perfectly compared to other samples. It might be attributed to the segregation of carbon onto the Ni (111) surface, whereas the graphene growth seems to be influenced by the rate of the carbon atom generation. It was found that the increment of carbon contributed to the high carbon content in cycles of refined cooking palm oil. Raman results reveal that the sample synthesis using third cycles refined cooking palm oil is weak D-peak, which indicates the low contribution of a defect structure. These reactions potentially decrease the layer stacking of graphene sheets according to the low value of defect and the higher ratio of I2D/IG = 0.3 respect to other samples.Graphene successfully formed on the Ni surface due to segregation and precipitation of high amount of carbon originated from the source material occurred at cooling process. The growth of graphene at different cycles of refined cooking palm oil using double thermal chemical vapour deposition method (DTCVD) was investigated. The samples were prepared at different cycles of refined cooking palm oil, which is unused (refined), first cycle, second cycles and third cycles at vaporization temperature of 350 °C and the temperature of Ni substrate constant at 900 °C. Comparison of the Fesem results indicated that the difference of cycles refined cooking palm oil has significant structural changes. Third cycles of refined cooking palm oil as precursor shown the graphene grain seems to growth perfectly compared to other samples. It might be attributed to the segregation of carbon onto the Ni (111) surface, whereas the graphene growth seems to be influenced by the rate of the carbon atom generation. It was found tha...
In this paper, we investigated the lateral interactions of ammonia molecules on the V3C2 surface using the methods of the density functional theory. The calculations were carried out using non-local functionals. We investigated the properties of the adsorption layer MXenes V3C2 methods of statistical physics. The adsorption isotherms were constructed using the SuSMoST program code. They made recalculation of adsorption isotherms from chemical potential to pressure.
This paper solves the problem of strength loads during the inserting a branch into the main line. The calculations carried out in a manual form and with the help of the Russian software START, which specializes in pipeline calculations. 3D-model of pipelines was designed to solve the problem and 3D-model visualized the using of the software Intergraph Smart Plant 3D. The results obtained in the development of the model, that made it possible to establish the most optimal characteristics of the pipeline tie-in for a strength loads and to identify the need to use reinforcement of this tie-in. In the course of the research, significant aspects of strength calculations studied, as well as features of the use of specialized software. The calculation used in the actual design of the CDU/VDU complex of the Omsk refinery.
The existing of pores and micro-crack in the hardened cement paste influences the strength itself. Nano silica produced from BRHA has been used in this study. Nano BRHA replacement levels of 0%, 10%, 20% and 30% by weight of cement were applied. The TGA/DTA and XRD has been conducted for hardened cement paste powder to analyses the effect of different partial replacement of Nano BRHA. It was found that the weight loss results for Ca(OH)2 seems decreasing with increasing in Nano BRHA replacement. The higher CSH percentage contained in cement paste was 10% of Nano BRHA replacement.
Dampers, which are thin plates located across the flow direction, are used in some apparatus for petrochemical and oil and gas production for the control of liquid flow. A mathematical model of multidirectional plates flow and the plates varying in size, locating in the translational flow of a continuous medium is developed. The model takes into account the possibility of calculation near the impermeable flow boundary. The model of inviscid fluid flow, the theory of complex variable theory and Joukowski transformation were used for the development. To verify the adequacy of the model, an experiment, with the pressure being measured by the method of strain gauging, is performed, when the plate moves along an impermeable flat surface. The discrepancy between the calculated and experimental values by the quantity from 24 to 27.5% is revealed, which is sufficient for preliminary calculations.
The Si doped ZnO nanopowders for varistor have been prepared at different sintering temperature using solid state method. The Si doped ZnO have been sintered at different temperatures 850, 950 and 1050 °C at air condition. The structural and densification of Si doped ZnO were determined using scanning electron microscopy (SEM), X-ray diffraction (XRD) analysis and digital density meter. It was found that the average grain size of Si doped ZnO varistor were 0.81, 1.05 and 2.10µm when sintered at 850, 950 and 1050 °C, respectively. The density of Si doped ZnO were 3.999, 4.453 and 5.332 g/cm3 when the sintering temperature increased from 850, 950 and 1050 °C, respectively. The density and average grain size of the Si-Doped ZnO is increased with increase of sintering temperature. The Si doped ZnO varistor at different sintering process are polycrystalline structure. It is revealed that the sintering temperature can influence the properties of Si doped ZnO ceramics which is suitable to be used in varistor application.
