Numerical simulation and experimental investigation of air cooling system using thermoelectric cooling system

Journal of Thermal Analysis and Calorimetry - Efficient air-conditioning inside the cars is a challenge in automobile industry. Thermoelectric is one of the new methods for air cooling. It has many...     

Design,synthesis, in vivo and in vitro studies of 1,2,3,4-tetrahydro-9H-carbazole derivatives,highly selective and potent butyrylcholinesterase inhibitors

Molecular Diversity - Inhibition of butyrylcholinesterase (BChE) might be a useful therapeutic target for Alzheimer’s disease (AD). A new series of 1,2,3,4-tetrahydro-9H-carbazole derivatives...     

Qualitative and quantitative assessment of extracted oil from Camelina sativa seed treated by dielectric-barrier discharge cold plasma

This study aimed to investigate the effects of dielectric-barrier discharge (DBD) cold plasma (CP) pretreatment on Camelina sativa “Soheil cultivar” seed. A DBD plasma reactor system was employed for this purpose. The experiments were performed by taking into account variables including voltages of 15, 18, and 21 kV and times of 2, 4, 8, and 16 min. The measured properties were oil yield extraction (%), oil colour parameters (CIEL*a*b*), protein content (meal) (%), surface analysis using Scanning Electron Microscopy (SEM), and fatty acids profile of Camelina sativa. The results revealed that the CP treatment had a significant improvement in different properties of the extracted oil. It was observed that the extracted oil was increased, with the increasing time of CP exposure. The treatments of CP enhanced the oil yield from 24.3 to 31.5%, and the optimal conditions were identified as 21 kV and 16 min. Also, the maximum protein amount was observed for the samples treated by CP (39.5%). The SEM analysis showed that the cell structures of pre-treated Camelina samples were damaged, thereby improved the oil extraction efficiency. The variations in the values of L*, a*, and b* (max-min) were calculated to be 3.9, −2.5, and 9.7, respectively, which indicated minor changes of CP treatment on the oil colour parameters. The treated samples showed considerable changes of enhancement in linolenic and linoleic acids among poly-unsaturated fatty acids; and a reduction in palmitic acid content, among saturated fatty acids.     

Piston scuffing fault and its identification in an IC engine by vibration analysis

In this paper, the effects of piston scuffing fault on engine performance and vibrations are investigated. A procedure based on vibration analysis is also presented to identify piston scuffing fault. To this end, an internal combustion (IC) engine ran under a specific test procedure. The engine parameters and vibration signals were measured during the experiments. To produce piston scuffing fault, three-body abrasive wear mechanism was employed. The experimental results showed that piston scuffing fault caused the engine performance to reduce significantly. The vibration signals were analyzed in time-domain, frequency-domain and time–frequency domain. Continuous wavelet transform (CWT) was used to obtain time–frequency representations. “dmey” wavelet was selected as the optimum wavelet type for this research among different wavelet types using the three criteria of energy, Shannon entropy and energy to Shannon entropy ratio. The results of CWT analysis by “dmey” wavelet showed that piston scuffing fault excited the frequency band of 2.4–4.7 kHz in which the frequency of 3.7 kHz was affected more. Finally, seven different features were extracted from the engine vibration signals related to the frequency band of 2.4–4.7 kHz. The results indicated that maximum, mean, RMS, skewness, kurtosis and impulse factor of the engine vibration related to the found frequency band increased significantly due to piston scuffing fault. The obtained results showed that the proposed method identified piston scuffing fault and discovered the vibration characteristics of this fault like frequency band. The results also demonstrated the possibility of using engine vibrations in piston scuffing fault identification.