Effects of turbulator with round hole on the thermo-hydraulic performance of nanofluids in a triangle tube

© 2019 Elsevier Ltd For investigating the thermal and hydraulic characteristics of water-based SiO2 nanofluids in a triangular tube with different turbulators, an experimental system has been designed and verified in this paper. The effects of different round hole diameters (d = 3 mm, 4 mm, 5 mm) and round hole pitch-rows (l = 5 cm, 10 cm, 15 cm) of perforated turbulators on the thermo-hydraulic characteristics are researched. Meanwhile, the influences of Reynolds numbers (Re = 400–8000) and nanoparticles mass fractions (D-I water, ω = 0.1%, 0.3%, 0.5%) are also studied. These experimental results show that, under the same circumstance, the nanofluids in the triangular tube with ω = 0.5% have the largest positive influence on the heat transfer enhancement ratio which is up to 16.73%. For a comprehensive study of the flow and heat transfer, thermal efficiency (comprehensive performance index) and exergy efficiency are adopted. It can be found that the larger the diameter and the smaller the pitch-row of the holes is, the greater the comprehensive evaluation index can be. In addition, all working conditions exhibit the superior exergy efficiency. The highest exergy efficiency can be got when Re = 6000 and ω = 0.5%

Experimental study on the flow and heat transfer characteristics of nanofluids in double-tube heat exchangers based on thermal efficiency assessment

Thermal performance and pressure drop of TiO2-H2O nanofluids in double-tube heat exchangers are investigated. The influence of the thermal fluid (water) volume flow rates (qv = 1–5 L/min), nanoparticle mass frictions (ω = 0.0%, 0.1%, 0.3% and 0.5%), nanofluids locations (shell-side and tube-side), Reynolds numbers of nanofluids (Re = 3000–12000), and the structures of inner tubes (smooth tube and corrugated tube) is analyzed. Results indicate that nanofluids (ω = 0.1%, 0.3% and 0.5%) can improve the heat transfer rate by 10.8%, 13.4% and 14.8% at best compared with deionized water respectively, and the number of transfer units (NTU) and effectiveness are all improved. The pressure drop can be increased by 51.9% (tube-side) and 40.7% (shell-side) at best under the condition of using both nanofluids and corrugated inner tube. When the nanofluids flow in the shell-side of the corrugated double-tube heat exchanger, the comprehensive performance of nanofluids-side is better than that of the smooth double-tube heat exchanger

Effect of corrugation pitch on thermo-hydraulic performance of nanofluids in corrugated tubes of heat exchanger system based on exergy efficiency

© 2019 Elsevier Ltd In this article, water and TiO2-H2O nanofluids are used as heat exchange mediums. The heat transfer and resistance coefficient of corrugated tubes with different corrugation pitches are studied by experimental method. The economy of experimental system is evaluated from the aspects of quantity and quality of energy by thermal and exergy efficiencies respectively. The heat transfer performance of nanofluids in the smooth tube can be enhanced by 2.64–16.9% compared with water under the same working conditions, while the corrugated tubes can improve the heat transfer performance by 4.8–66.3%. When the mass fraction of the nanofluid is 0.5%, the corrugated tubes with different corrugation pitches can increase the heat transfer by 36.3% (P = 6 mm), 40.3% (P = 4 mm) and 44.5% (P = 2 mm) respectively. For thermal efficiency, the results prove that when the Reynolds number is larger than 6000, the comprehensive evaluation indexes of corrugated tubes are much larger than that of smooth tube, and the maximum can reach 1.5637. For exergy efficiency, the research results show that the exergy efficiency of the smooth tube is better than that of the corrugated tubes

Protein expression and fine interaction mechanism of banana MuMADS1 and MaOFP1

MuMADS1 is an AGAMOUS (AG)-like MADS-box gene previously isolated from banana fruits. Previous investigation demonstrated that the K-domain of MuMADS1 interacts with MaOFP1. However, the expression characteristics of MuMADS1 and MaOFP1 proteins in banana fruits and their fine interaction mechanism need to be further investigated. In the present study, the expression characteristics of MuMADS1 and MaOFP1 proteins during banana fruits development and ripening process was investigated by Western blot. The interaction of MuMADS1 and MaOFP1 was demonstrated again by Pull down. The fine interaction mechanism of K-domain of MuMADS1 interacting with the ovate-domain and non-ovate-domain of MaOFP1 was further investigated by yeast two hybrid (Y2H) and bimolecular fluorescence complementation (BiFC) assay. The result indicated that MuMADS1 was differentially expressed during Baxi (BX) and Fenjiao (FJ) fruits development and ripening process. With the progress of banana fruit development, the expression level gradually increased and reached the peak at 0 DPH, and then gradually decreased. The expression level of MaOFP1 during BX and FJ fruits development and ripening process was significantly lower than MuMADS1. Moreover, the expression level of MaOFP1 in FJ was higher than in BX. The K-domain of MuMADS1 interacted with the ovate-domain of MaOFP1. These results laid the foundation for deeply understanding the role of MuMADS1 and MaOFP1 in banana fruits and provide gene resources for banana fruit ripening regulation

Pregnancy-Specific Beta-1-Glycoprotein 1 Increases HTR-8/SVneo Cell Migration through the Orai1/Akt Signaling Pathway

The impaired invasion ability of trophoblast cells is related to the occurrence of preeclampsia (PE). We previously found that pregnancy-specific beta-1-glycoprotein 1 (PSG1) levels were decreased in the serum of individuals with early-onset preeclampsia (EOPE). This study investigated the effect of PSG1 on Orai1-mediated store-operated calcium entry (SOCE) and the Akt signaling pathway in human trophoblast cell migration. An enzyme-linked immunosorbent assay (ELISA) was used to determine the level of PSG1 in the serum of pregnant women with EOPE. The effects of PSG1 on trophoblast proliferation and migration were examined using cell counting kit-8 (CCK8) and wound healing experiments, respectively. The expression levels of Orai1, Akt, and phosphorylated Akt (p-Akt) were determined through Western blotting. The results confirmed that the serum PSG1 levels were lower in EOPE women than in healthy pregnant women. The PSG1 treatment upregulated the protein expression of Orai1 and p-Akt. The selective inhibitor of Orai1 (MRS1845) weakened the migration-promoting effect mediated by PSG1 via suppressing the Akt signaling pathway. Our findings revealed one of the mechanisms possibly involved in EOPE pathophysiology, which was that downregulated PSG1 may reduce the Orai1/Akt signaling pathway, thereby inhibiting trophoblast migration. PSG1 may serve as a potential target for the treatment and diagnosis of EOPE