Enhancement of refrigeration system performance by refrigerant capillary injection in evaporator

In this paper, the enhancement of refrigeration system performance by refrigerant capillary injection in evaporator was experimentally investigated. An experimental bench was developed in order to compare the performance of a refrigeration system operating in conventional throttling and capillary injection modes. The temperature distribution in the evaporator and the compressor electrical consumption were determined, showing that in the capillary injection mode, the refrigeration system was more stable, its time to reach the steady state was reduced by 62.5 % and its COP was enhanced by 9 %.

Enhanced Oil Recovery Application of Nanoparticles in Niger Delta Water-Wet Reservoir Rock

In this paper, the enhanced oil recovery potential of the application of nanoparticles in Niger Delta water-wet reservoir rock was investigated. Core flooding experiments were conducted on the sandstone core samples at 25 °C with the applications of nanoparticles in secondary and tertiary injection modes. The oil production during flooding was used to evaluate the enhanced oil recovery potential of the nanoparticles in the reservoir rock. The results of the study showed that the application of nanoparticles in tertiary mode after the secondary formation brine flooding increased oil production by 16.19% OIIP. Also, a comparison between the oil recoveries from secondary formation brine and nanoparticles flooding showed that higher oil recovery of 81% OIIP was made with secondary nanoparticles flooding against 57% OIIP made with formation brine flooding. Finally, better oil recovery of 7.67% OIIP was achieved with secondary application of nanoparticles relative to the tertiary application of formation brine and nanoparticles flooding. The results of this study are significant for the design of the application of nanoparticles in Niger Delta reservoirs.

Spectrophotometric determination of vitamin B1 in dosage forms using drugs compounds as reagents by normal and reverse flow injection methods

Background: Thiamine hydrochloride (THY), also known as vitamin B1, is a water soluble vitamin usually found in food, and considered as a dietary supplement and treatment in case of vitamin deficiency for example in malabsorption and chronic diarrhea. Objective: Rapid, green and sensitive methods for the assay of vitamin B1 (thiamine hydrochloride, THY) in pharmaceutical forms, using normal and reverse flow injection manifolds and sulfonamide drugs as green and safe reagents were reported. Sulfamethoxazole and sulfadimidine drugs were used rather than toxic and expensive reagents. Methods: nFIA and rFIA manifolds were used for automated the reaction of THY with diazotized sulfamethoxazole (DSMZ) and diazotized sulfadimidine (DSDM) in alkaline medium respectively. The absorbance of the resultant red-orange azo dyes was monitored spectrophotometrically at λmax 494 and 496 nm for both methods respectively. Results: The linearity of the suggested methods was in the ranges 2–80 µg/mL (LOD 0.69 µg/mL, % RSD 0.32, n=6) for nFIA method and 0.5-70 µg/mL (LOD 0.29 µg/mL, %RSD 0.85, n=6) for rFIA. Sampling frequency was 84 and 51 injections per hour for nFIA and rFIA methods respectively. Chemical and physical variables for both methods were studied carefully. Conclusion: Both flow injection modes were effectively applied in assay of THY in its pharmaceutical forms. The results were compared with those of standard pharmacopeia method and the statistical analysis indicated insignificant differences in accuracy and precision between the methods.