Analytical Study on the Low-Frequency Vibrations Isolation System for Vehicle’s Seats Using Quasi-Zero-Stiffness Isolator

Improving the vibration isolation for the seat of small vehicles under low excitation frequencies is important for providing good comfort for the driver and passengers. Thus, in this study, a compact, low-dynamic, and high-static stiffness vibration isolation system has been designed. A theoretical analysis of the proposed quasi-zero stiffness (QZS) isolator system for vehicle seats is presented. The isolator consists of two oblique springs and a vertical spring to support the load and to achieve quasi-zero stiffness at the equilibrium position. To support any additional load above the supported weight, a sleeve air spring is used. Furthermore, the two oblique springs are equipped with a horizontal adjustment mechanism that is aimed to reach higher frequencies with the existed stroke when a heavy load is applied. The proposed system can be fitted for small vehicles, especially for B-segment and C-segment cars. Finally, the simulation results reveal that the proposed system has a large isolation frequency range compared to that of the linear isolator

Thermogravimetric kinetics study of scrap tires pyrolysis using silica embedded with NiO and/or MgO nanocataly

In this study, a set of three new silica-based embedded with NiO and/or MgO nanocatalysts (SBNs) have been prepared and tested for the pyrolysis of scrap tires (STs). The intent is to identify and optimize the best nanocatalyst that decreases the operating temperature and speeds up the pyrolysis reaction rate. The influence of the three prepared SBNs nanocatalysts on STs was scrutinized using thermogravimetric analysis (TGA) and Fourier transform infrared spectroscopy (FT-IR). The kinetic triplets were estimated utilizing the isoconversional method of the Ozawa–Flynn–Wall (OFW) corrected model. Experimental TGA and FT-IR results showed a thermal decomposition of all volatile organic additives alongside the polyvinyl compounds at a lower temperature in the presence of these SBNs. However, a competitive decomposition behavior appeared for each SBN nanocatalysts. The kinetic triplets’ findings showed different effective activation energy trends at two different conversion regions (low and high conversions), suggesting different reaction mechanisms confirmed by the reaction kinetic models. Interestingly, NiO-MgO-SBNs showed the highest reaction rate for this thermo-pyrolysis of STs, which could be because of synergetic interaction between NiO and MgO nanoparticles. Moreover, the results of the change in Gibbs free energy of activation (ΔG‡) indicated the promising catalytic activity for those SBNs by promoting the spontaneity of pyrolysis reaction. These proof-of-concept findings could promote the futuristic use of NiO-MgO-SBNs at the industrial level toward sustainable ST pyrolysis.The authors thankfully acknowledge Deanship of Scientific Research in An-Najah National University, Nablus, Palestine for providing financial support to this study via Project Number (ANNU-1819-Sc008). The technical assistance provided by Mr. Nafith Dwikat and by the faculty of Science at An-Najah National University (ANNU), Nablus, Palestine is also highly appreciated.Scopu

Competitive adsorption of Alizarin Red S and Bromocresol Green from aqueous solutions using brookite TiO2 nanoparticles: experimental and molecular dynamics simulation

In this work, the effective adsorption and the subsequent photodegradation activity, of TiO2 brookite nanoparticles, for the removal of anionic dyes, namely, Alizarin Red S (ARS) and Bromocresol Green (BCG) were studied. Batch adsorption experiments were conducted to investigate the effect of both dyes' concentration, contact time, and temperature. Photodegradation experiments for the adsorbed dyes were achieved using ultraviolet light illumination (6 W, λ = 365 nm). The single adsorption isotherms were fitted to the Sips model. The binary adsorption isotherms were fitted using the Extended-Sips model. The results of adsorption isotherms showed that the estimated maximum adsorption uptakes in the binary system were around 140 mg g-1 and 45.5 mg g-1 for ARS and BCG, respectively. In terms of adsorption kinetics, the uptake toward ARS was faster than BCG molecules in which the equilibrium was obtained in 7 min for ARS, while it took 180 min for BCG. Moreover, the thermodynamics results showed that the adsorption process was spontaneous for both anionic dyes. All these macroscopic competitive adsorption results indicate high selectivity toward ARS molecules in the presence of BCG molecules. Additionally, the TiO2 nanoparticles were successfully regenerated using UV irradiation. Moreover, molecular dynamics computational modeling was performed to understand the molecules' optimum coordination, TiO2 geometry, adsorption selectivity, and binary solution adsorption energies. The simulation energies distribution exhibits lower adsorption energies for ARS in the range from - 628 to - 1046 [Formula: see text] for both single and binary systems. In addition to that, the water adsorption energy was found to be between - 42 and - 209 [Formula: see text]