Experimental analysis of the efficacy of vegetable oil-based nanolubricants for improving journal-bearing performance

Author(s):  
Anil Dhanola ◽  
Hem Chander Garg

The present experimental study explores the performance of Hydrodynamic journal bearings operating with vegetable oil-based nanolubricants. For this study, titanium oxide nanoparticles have been added to canola oil by varying the volume fraction from 0% to 0.04%. An assessment of performance characteristics has been done by using a journal-bearing test rig under different operating conditions. The outcome of the experimental results aimed at the addition of nanoparticles to base lubricants to improve the performance was observed to be favorable. However, under high operating conditions, the influence of nanoparticles is observed to be less useful. The fluid film pressure of nanolubricants increased up to a specific volume concentration of titanium oxide nanoparticles (i.e. 0.02%) beyond which no further enhancement was observed. At a load of 3000 N, the fluid film pressure increased up to 10%, when a bearing is lubricated using canola oil with a 0.02% volume fraction of nanoparticles. The heat transfer rate was found to be higher for nanolubricants in comparison to a base oil and the fluid film temperature was reduced by up to 15% at a volume fraction of 0.04%. Furthermore, rheological studies reveal that the prepared nanolubricants exhibited Newtonian behavior under the given conditions. The percentage increment of viscosity varied from 2.1% to 15.4% and 2.43% to 13.89% for a volume fraction ranging from 0.01% to 0.04% at a temperature of 40 °C and 100 °C, respectively. The dynamic light scattering results confirmed that the particles were well distributed in a base lubricant without much aggregation.

2020 ◽  
Vol 16 (4) ◽  
pp. 337-343
Author(s):  
Shaimaa E. Abdel-Ghany ◽  
Eman El-Sayed ◽  
Nour Ashraf ◽  
Nada Mokhtar ◽  
Amany Alqosaibi ◽  
...  

Background: Hepatocellular carcinoma is the second leading cause of cancer-related deaths among other types of cancer due to lack of effective treatments and late diagnosis. Nanocarriers represent a novel method to deliver chemotherapeutic drugs, enhancing their bioavailability and stability. Methods: In the present study, we loaded gold nanoparticles (AuNPs) and titanium oxide nanoparticles (TiO2NPs) with ERL to investigate the efficiency of the formed composite in inducing apoptosis in HepG2 liver cancer cells. Cytotoxicity was assessed using MTT assay and cell phase distribution was assessed by flow cytometry along with apoptosis detection. Results: Data obtained indicated the efficiency of the formed composite to significantly induce cell death and arrest cell cycle and G2/M phase. IRF4 was downregulated after treatment with loaded ERL. Conclusion: Our data showed that loading ERL on TiO2NPs was more efficient than AuNPs. However, both nanocarriers were efficient compared with control.


2016 ◽  
Vol 26 (2) ◽  
pp. 157-159 ◽  
Author(s):  
Ning Luo ◽  
Hong Wen Jing ◽  
Zhan Guo Ma ◽  
Weidong Liu ◽  
Liangchi Zhang ◽  
...  

2019 ◽  
Vol 141 (11) ◽  
Author(s):  
Eliott Guenat ◽  
Jürg Schiffmann

Abstract High-speed small-scale turbomachinery for waste heat recovery and vapor compression cycles is typically supported on gas-lubricated bearings operating close to the saturation conditions of the lubricant. Under particular conditions, the gas film might locally reach the saturation pressure with potentially hazardous effects on the performance of the gas bearing. The present work introduces a model based on the Reynolds equation and the development of cavitation modeling in liquid-lubricated bearings for condensing gas bearings. The effect of condensation on load capacity and pressure and density profiles is investigated for two one-dimensional bearing geometries (parabolic and Rayleigh step) and varying operating conditions. The results suggest that the load capacity is generally negatively affected if condensation occurs. An experimental setup consisting of a Rayleigh-step gas journal bearing with pressure taps to measure the local fluid film pressure is presented and operated in R245fa in near-saturated conditions. The comparison between the evolution of the fluid film pressure under perfect gas and near saturation conditions clearly suggests the occurrence of condensation in the fluid film. These results are corroborated by the very good agreement with the model prediction.


2018 ◽  
Vol 55 (4) ◽  
pp. 616-619 ◽  
Author(s):  
Eugenia Eftimie Totu ◽  
Corina Marilena Cristache ◽  
Selim Isildak ◽  
Ozlem Tavukcuoglu ◽  
Aida Pantazi ◽  
...  

The present paper is focused on analyzing if appropriate adhesion between the polymeric matrix and titania filler nanoparticles is obtained for the PMMA-TiO2 photo-curable dental material, suitable for application in RP - stereolithography (SLA) for complete denture manufacturing. It was found that different amounts, between 0.2% and 2.5 % (w/w%), of added titanium oxide nanoparticles slightly modify the structural behavior of the PMMA polymeric matrix. The material characterization was carried out using FT-IR and microscopy techniques.


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