An Atypical Presentation of Raynaud's Disease

Objective: A 57-year-old female with a 33-year history of constant hand discoloration and paronychia had undergone multiple evaluations with a failure to find a diagnosis. She continues to undergo an evolving treatment regimen and diagnostic workup in an effort to find a long-eluded diagnosis. Clinical Presentation: She began to develop superficial ulcerations over the proximal phalanx of her fingers, often pruritic and erythematous, with pain and edema. Intervention: She has since been managed with nifedipine and sildenafil and intermittent stellate ganglion blocks. Conclusion: Despite still lacking a formal diagnosis, her constellation of symptoms is most likely the result of an atypical presentation of Raynaud's disease. (C) 2019 The Author(s) Published by S. Karger AG, Basel.Open access journalThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

Energetic and exergetic analysis of a domestic refrigerator system with LPG as a replacement for R134a refrigerant, using POE lubricant and mineral oil based TiO 2 -, SiO 2 - and Al 2 O 3 -lubricants

This paper experimentally investigated energetic and exergetic performance analysis of a domestic refrig- erator using R134a and LPG refrigerants with different lubricants (polyol-ester (POE), mineral oil (MO), and TiO 2 , SiO 2 , Al 2 O 3 nanoparticles dispersed in mineral oil).The energetic and exergetic performance analysis of the domestic refrigerator were investigated with test parameters including compressor power consumption, cooling capacity, coefficient of performance (COP), discharge temperature, irreversibility in the components, total irreversibility and second law efficiency. Findings showed that the lowest com- pressor power consumption and total irreversibility were observed in refrigerator with 40 g charge of LPG/TiO 2 -MO lubricant (0.2 g/L of TiO 2 ); these values of compressor power consumption and total ir- reversibility were 15.87% and 31.69%, respectively, lower than for R134a/POE lubricant. In addition, the domestic refrigerator using LPG refrigerant at 40 g charge with TiO 2 -MO (0.2 g/L TiO 2 ) lubricant, had the highest COP and second law efficiency among the selected nano-lubricants. These values of COP and second law efficiency were 56.32% and 47.06%, respectively, higher than that of R134a/POE. Futhermore, compressor discharge temperature of the domestic refrigerator with 40 g charge of LPG/TiO 2 -MO lubricant (0.2 g/L of TiO 2 ) was found to be lower than that of R134a/POE. Hence, extended compressor life may be expected with the adoption of TiO 2 -Mineral oil lubricant. It can be concluded that based on energetic and exergetic performance analysis, the domestic refrigerator using the 40 g charge of LPG/TiO 2 -MO (0.2 g/L TiO 2 ) performed better than R134a/POE

Performance of an Iso-Butane Driven Domestic refrigerator infused with various concentrations of Graphene based Nanolubricants

0.2, 0.4 and 0.6 g/L) of graphene based nanolubricants and selected mass charges (40, 50, 60 and 70g) of R600a refrigerant was studied. The steady state energetic performance of the domestic refrigerator was evaluated with test parameters including cabinet temperature, compressor power consumption, power per ton of refrigeration (PPTR) and coefficient of performance (COP). Findings showed that the lowest compressor power consumption and cabinet temperature observed within the system were 65 W and -12oC when infused with either 40g and 0 g/L or 60g and 0.2 g/L nanofluid mixtures. In addition, the utilization of 60 g and 0.2 g/L mixtures gave the highest PPTR value of 5.22 while the maximum COP value of 0.76 was seen with 70 g and 0 g/L respectively. In conclusion, the application of graphene based nanolubricants within the system significantly improved the performance

Performance of a Domestic Refrigerator infused with Safe Charge of R600a refrigerant and various concentration of TiO2

economically viable flammability risk reduction methodology. This study presents an experimental investigation a safe R600a refrigerant mass charge of 30 g and various concentrations of TiO2 nano-lubricants (0.2, 0.4 and 0.6g/L) in a slightly modified R134a domestic refrigerator. Performance parameters investigated at selected evaporator temperatures were instantaneous and mean power consumption, per power ton refrigeration (PPTR), discharge temperature and coefficient of performance (COP) respectively. Findings showed that the mean PPTR and power consumption range were 0.79 - 1.05 and 73 - 86.33 W. In addition, mean discharge temperature and COP range were 50 - 62oC and 3.23 - 4.03 respectively. In conclusion, the adoption of TiO2 nanoparticles enhanced the cooling rate and energy saving potential of the system considerabl