Enhancing the Thermophysical Properties of Lubricating Oils of Refrigeration System Using CuO/CeO2 as a Mixture of Nanoparticles

HudaElslam Mohamed, Ali A. Salama, Abdussalam Ali. Ahmed, Unal Camdali — Tue, 12 Nov 2024 00:00:00 +0000

The compressor is the heart of the refrigeration system, extension of its life and preservation of its moving parts such as pistons, rotors, valves, connecting rods and cranks lubrication require improvement. Recently the studies focus on the use nanoparticles with lubricants in refrigeration and air conditioning systems in view of their significant impact on improving the coefficient of performance of these systems as well as thermophysical properties of pure lubricating oils and thus reducing energy consumption. In this study, nanoparticles were synthesized in an easy and cheap way and from materials available in chemistry laboratories as following copper oxide, cerium oxide, mixture 1 consisted of 50% copper oxide with 50% cerium oxide, mixture 2 consisted of 60% copper oxide with 40% cerium oxide, mixture 3 consisted of 70% copper oxide with 30% cerium oxide, mixture 4 consisted of 40% copper oxide with 60% cerium oxide, and mixture 5 consisted of 30% copper oxide with 70% cerium oxide to study their effectiveness on enhancing the thermophysical properties of POE, PAG lubricating oil using mathematical equations available from earlier studies. The results obtained from the mathematical equations showed an increase in the viscosity of POE from 40 mm2/sec to 45 mm2/sec at 0.05 wt.% and reached 108.86 mm2/sec by increasing the concentration of nanoparticles to 0.33wt.%, as well as the improvement of viscosity of PAG from 46 mm2/sec to 52.9 mm2/sec at the concentration of nanoparticles 0.05 wt.%, recording a significant improvement when the concentration of nanoparticles reached 0.33 wt.%, as well as for the rest of the other physical properties. This is consistent with earlier studies that confirmed the improvement of the physical properties of lubricants through mixing them with nanoparticles.

A Review of Microstrip Bandstop Filters: Analysis and Design Techniques

Selvakumar Arumugam, Kanaparthi V. Phani Kumar, Rusan Kumar Barik — Sat, 30 Nov 2024 00:00:00 +0000

High-performance RF transceiver systems create large demands in multimode wireless communication system applications with high-frequency suppression, increased spectral utilization, and flexibility to control stopband and passband frequency characteristics. This review analyzes microstrip bandstop filters mentioned in from recent research articles focusing on their performance characteristics, design techniques and applications. Filters are categorized into five categories, namely, Single stopband bandstop filter, Dual stopband BSF, Wide stopband BSFs, Low pass with Wide stopband BSFs, and reconfigurable filters, this article deals with a study of these filters. An extensive analysis of the filter design techniques including the type of resonators, coupled line sections, open/short-circuited stubs, DGS/DMS, and flexible switching devices has been made with comparison and exploration of the simulated, measured frequency responses in each category.

Journal of High-Frequency Communication Technologies

Enhancing the Thermophysical Properties of Lubricating Oils of Refrigeration System Using CuO/CeO2 as a Mixture of Nanoparticles

A Review of Microstrip Bandstop Filters: Analysis and Design Techniques