Papers by Keyword: Conversion

Abstract: Regeneration of industrial catalysts is a better way of increasing the catalytic activity of a catalyst. These catalysts are used in the production of sulfuric acid, in the conversion of sulfur dioxide to sulfur trioxide. They lose their efficiency and activity over time, so it is preferable to regenerate the catalyst instead of discarding it as waste, using a thermal regeneration method followed by chemical treatment by impregnation with different percentages of V₂O₅, 10%, 20% and 30%. They are then examined using techniques known as XRD and FTIR. The IR spectrum shows that the catalyst doped with 30% V₂O₅ has the same bands as the fresh catalyst. Finally, the catalytic test carried out by iodometric assay shows that the catalyst regenerated with 20% V₂O₅ has a conversion rate of 63%, identical to that of fresh catalyst.

Abstract: The article analyzes the reasons hindering the mass use of alternative fuels in the field of energy consumption of domestic transport, which for the most part have lower energy and kinetic indicators of combustion in comparison with traditional fuels. A new approach to solving the problem of improving the environmental and energy-saving indicators of combustion of alternative fuels based on their preliminary thermochemical processing - conversion on board a vehicle is presented. The results of a preliminary analytical study of the parameters of the on-board conversion process for a number of potentially acceptable types of alternative fuels are presented in order to assess the efficiency of this process. The possibility of practical implementation of the proposed process for improving the combustion indicators of alternative fuel with an assessment of its efficiency was tested based on the results of experimental approbation in the conditions of full-scale engine tests. According on the results of the study, the expediency of using this process in transport technologies is justified due to the technical simplicity of its implementation and efficiency. Thermocatalytic reactor is the simplest design of a heat exchanger, the mass and dimensional characteristics of which (in the volume of a conventional muffler) ensure the convenience of its installation in the engine exhaust system. The component composition of these products contains reactive compounds that contribute to the improvement of environmental and energy-saving indicators of the fuel combustion process, and an increase in the efficiency of the engine's operating cycle.

Abstract: The synthesis of the Ni-Mo sulfated zirconia (NiMo-SZ) catalyst and its application to convert waste cooking oil into biofuel was successfully conducted. The synthesis process was started with a sulfation process on the zirconia oxide (ZrO₂) using 0.5, 1.0, and 1.5 M sulfuric acid (H₂SO₄) through wet impregnation to obtain sulfated zirconia (SZ). Solid SZ with the highest total acidity value was calcined at temperature 500, 550, 600, 650, and 700 ^°C. Solid SZ calcined with the optimum temperature was treated with Ni and Mo metals at 1%, 2%, and 3% (w/w) through a hydrothermal method. Pure ZrO₂, SZ, and 1, 2, and 3 NiMo-SZ catalysts were used in the hydrocracking of used cooking oil into biofuel. The results showed that the 1.5 M SZ catalyst calcined at 500 °C had the highest acidity value of 3.8137 mmol/g. The 3-NiMo-SZ catalyst had the best activity valuing at 80.54%, while 1-NiMo-SZ produced the best selectivity in producing gasoline fraction until 73.93%.

Abstract: The efficiency of batteries, supercapacitors, and dye-sensitized solar cells for energy storage and harvesting processes depends on the relative energy levels and the charge transfer kinetics at the electrode/electrolyte interface. Owing to their distinctively tunable properties including non-volatility, low flammability, wide electrochemical stability, inherent conductivity, and high thermal stability, developing low viscosity ionic liquids (ILs) is vital for energy device fabrication. In this work, 1-methylimidazolium ILs were synthesized by a one-step sonochemical solventless reaction and were characterized using FT-IR, ¹H-NMR, and ¹³C-NMR spectroscopy to confirm their structure. Hybrid electrolytes based on the 1-methylimidazolium chloride ([MIM]Cl) infused with titanium dioxide (TiO₂) particles at varying concentrations were prepared, and the effect of solute concentration on their electrochemical and interfacial properties was investigated. Ionic conductivity results revealed that the as-prepared [MIM]Cl-TiO₂-0.5% hybrid electrolytes exhibited a higher conductivity in comparison with neat [MIM]Cl. Furthermore, cyclic voltammetry was used to determine their electrochemical stability window and revealed that a wide ESW of 3.56 ± 0.01 V was also obtained by [MIM]Cl-TiO₂-0.5% attributed to the enhanced surface tension of 35.92 ± 0.07 mN/m due to the addition of TiO₂ particles. This observation was validated by the generated pendant drop images showing the remarkable correlation of solute concentration with surface tension and ESW of the hybrid electrolytes. The utilization of these metal oxide-infused solvent-free IL as a substitute for aqueous-and organic-based electrolytes can address issues on electrochemical stability and provide insight in suppressing self-discharge processes, especially when used at higher potentials.

Abstract: Energy is a fundamental element for the development of societies, with energy transformation from renewable sources a challenging theme throughout the world. In Brazil, the energy matrix is composed mainly of non-renewable sources such as petroleum and its derivatives, but the transformation for electricity supply is carried out mainly by hydroelectric plants. This paper presents data from the National Energy Balance between the years 2011 to 2016, regarding the internal supply of energy, as well as the sectors that use it as their main source of electricity, allowing a better visualization of the national scenario. In view of the problem, the main objective is to present possibilities for the production of energy by ocean waves, a concept already studied in developed countries. For example, three tested converter devices are considered: one in Norway and two in Denmark. Considering this possibility from the power of the ocean waves in the world, as well as the climatic, geographical and wave characteristics of Brazil, this work indicates the possibility of a significant increase in the Brazilian energy matrix through the use of the energy of the ocean waves. However, there is a growing need to foster research and development projects in this area, so that this alternative source of energy will become viable.

Abstract: The aim of this work is development of method to determine the conversion of epoxy groups in the epoxy amine resins based on the epoxy oligomer ED-20 and hardener DDM. The studies were carried out in the NIR range. The mathematical division of the spectrum of the resins into individual peaks was used and concentrations of the functional groups were calculated on them. The dependence of the maximum conversion of epoxy groups in the resins after curing at 140 ^оС was obtained.

Abstract: Microfluidic chip injection photocuring is a new method for microfluidic chip fabrication. The accuracy of microfluidic chip photocuring has an important impact on the reliability of microfluidic chip. The reaction rate of photocuring system directly affects the final quality and efficiency of microfluidic chip. The rapid reaction rate of photocuring system will lead to poor feeding effect of the reaction system. The forming accuracy is affected, and the reaction rate is too slow, which will increase the forming time and affect the forming efficiency. In this paper, the conversion rate and reaction rate of different active monomers and oligomers used in the formulation system of microfluidic chips were measured on-line. The photocuring reaction kinetics of microfluidic chips was studied, and the influence of the formulation system on the photocuring reaction was explored, which laid a foundation for optimizing the formulation of microfluidic chips.

Abstract: Retinal images are routinely acquired and assessed to provide diagnostic for many important diseases like diabetic retinopathy. People with proliferative retinopathy can reduce their risk of blindness by 95 percent with timely treatment and appropriate follow-up care. The color constancy is used in this context to define the ability of the visual system to estimate an object color transmitting an unpredictable spectrum to the eyes. In this paper, a Gray World method was proposed by assuming the average of the surface reflectance of a typical scene is some pre-specified value. The main idea based on illumination estimated using the statistical region data. The effectiveness of the Gray Word method and normal gray technique was calculated by using Mean Square Error (MSE) and Peak Signal to Noise Ratio (PSNR). The Gray World achieved the highest PSNR and lowest MSE proved that the image quality was improved. The proposed method can be used to help the ophthalmologist to detect a lesion in the retinal image automatically. Through the contrast variation in retinal images, the disease can be recognized very well.

Abstract: Marine structure, coralline materials were converted to calcium phosphate using two different phosphate solutions. The aim was to study the conversion mechanisms under acidic and basic environment at moderate conditions of temperature. Crystal growth and morphology of converted corals were characterized by XRD and SEM respectively. The results suggested that under acidic conditions (H₃PO₄), dissolution and precipitation control and direct the crystal formation and morphology in which transition from plate like to rod like hydroxyapatite structure was favoured. Metastable phase such as monetite formed and transformed to HAp during reaction. During the first hour of the dissolution a monetite and hydroxyapatite mixture precipitates and then the full conversion to hydroxyapatite is observed. On the other hand, under basic conditions (NH₄)₂HPO₄, just diffusional surface conversion of the calcium carbonate structure of coralline materials to hydroxyapatite and a very small amount of tri-calcium phosphate is observed. The mechanism can be classified as the solid-state topotactic ion-exchange reaction mechanism.

Abstract: Different methods are used to prepare gallium-containing zeolites of a ZSM-5 structure. Their acidic and structural characteristics are investigated and the effect of the method of gallium introduction into a zeolite on distribution and ratio of acid sites of different strengths, as well as on pore volume and diameter is determined. The relationship between the localization of gallium introduced into a zeolite by different methods and its electronic state and the catalytic activity and selectivity of the resulting contacts in the course of propane aromatization is established. The Ga-containing zeolite prepared by impregnation is found to be the most efficient catalyst for conversion of propane into aromatic hydrocarbons.