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Ferrofluids are type of colloidal systems which are known as an important group of smart materials. Their physical properties adaptively change with magnetic strength. These characteristics of ferrofluid must be applied for improving the efficiency. In this work, thermal performance of a type of ferrofluid with a viscosity correlation dependence on temperature, magnetic field and volume fraction was scrutinized. FVM is applied for solving momentum, conservation and heat transfer equation. To consider the effect of solid part in thermal behavior of system, the conjugate heat transfer was considered. The wire is placed in the bottom of channel, and the equation of non-uniform external magnetic field is defined as user function. The results indicated in a comparison of studied parameters as non-dimensional variables, it is demonstrated magnetic number and wave amplitude result in the maximum impact on improving Nu and the worst impact on friction coefficient and pressure loss correspondence to volume fraction and Reynolds number. The results also predicted significant changes in viscosity under influence of effective parameters, especially Kelvin force. [ABSTRACT FROM AUTHOR]

Utilizing passive methods is an efficient way in order to improve the thermal performance of heat exchangers. The novelty of the present paper is that two kinds of passive techniques for heat transfer enhancement, including a corrugated tube equipped with a coiled wire as turbulator, are combined in the present study. Heat transfer and pressure drop in a corrugated tube with a wire coil are analyzed numerically by a commercial CFD software. The range of the considered Reynolds number is 5000–20,000, which guarantees that the flow regime is fully turbulent. The effects of two different geometrical parameters and of two flow operating parameters, namely the Reynolds and Prandtl numbers, are numerically investigated. The conservative equations for momentum are closed using the k-ε realizable model. Results indicate that the geometrical and fluid flow parameters have significant effects on the thermal performance of the system. When one increases the pitch ratio of the wire coil (P/d), the heat transfer enhancement ratio NuER decreases. The maximum decrease is obtained for P/d = 5 with − 7.78% at Re = 20,000 in comparison with the baseline case P/d = 2. The maximum increase in the performance evaluation criterion (PEC) is observed at Re = 5000: + 11.16% and + 17.4% for P/d = 3 and P/d = 5, respectively. The configuration with a roughness height equal to e = 3 mm exhibits the best thermal performance with a maximum enhancement in terms of NuER of + 3.3% at Re = 10,000 in comparison with the baseline case e = 0.5 mm. By considering the PEC number, increasing the parameter e has a negative effect on the thermal performance of the proposed system. [ABSTRACT FROM AUTHOR]

Background: Water scarcity is responsible for losses in the yield of many plants and this is expected to continue due to climate change. However, cowpea which is known for its drought tolerance, is considered as a plant without limitations to climate change. A two-year experiment was conducted to evaluate the effect of water restriction on phenolic compounds, antioxidant capacity and leaf nutrients concentration of four cultivars of cowpea at different growth stages. At second leaf stage, two irrigation regimes were initiated (Water irrigation was applied after 75% and 55% of field capacity, as well watered and drought stress treatment, respectively).Plants samples were collectedat three stages(immature pod, immature seed and dry seed stage) for total phenol and flavonoids content, ortho-diphenols andantioxidant capacity measurement and leaves sampling for nutrients concentration. Results: The results indicated that polyphenolic compounds and antioxidant capacity increased under drought conditions. However, in both irrigation regimes, immature pods had the higher polyphenolic compounds, antioxidant capacity and leaf nutrients concentration rather than immature seeds and dry seeds. Among the genotypes, ILC482 revealed the highest content of total phenolics and ortho-diphenols (6.9 and 3.57 mg GA g−1dry weight, respectively). In addition, nitrogen, phosphorus and magnesium concentration of leaves were higher in ILC482 genotype. Under drought stress, ILC482 maintained higher ABTS radical scavenging capacity (0.0083 mmol Trolox g−1dry weight) compared to other genotypes. Conclusions: It is suggested that drought stress affect the quality of cowpea productions through polyphenolic compounds, ABTS and DPPH radical scavenging capacity which can be used as a helpful strategy to save water in the regions where water is scare. [ABSTRACT FROM AUTHOR]

Characterization of near-interface traps (NITs) in commercial SiC metal–oxide–semiconductor field-effect transistors (MOSFETs) is essential because they adversely impact both performance and reliability by reducing the channel carrier mobility and causing threshold-voltage drift. In this work, we have applied a newly developed integrated-charge technique to measure the density of NITs that are active in the above-threshold region of commercial SiC MOSFETs. The results demonstrate that NITs trap about 10% of the channel electrons for longer than 500 ns. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the effect of three intravitreal bevacizumab (IVB) injections alone or in combination with intravitreal erythropoietin (EPO) in the treatment of refractory diabetic macular edema (DME). Methods: In a randomized double-blind clinical trial, 48 eyes of 34 diabetic patients with refractory DME were enrolled. Eyes were randomly assigned to receive either 3 monthly injections of 0.05 cc (1.25 mg) IVB plus 0.05 cc (1000 unit) EPO or 0.05 cc (1.25 mg) IVB alone. Main outcome was best-corrected visual acuity (BCVA) changes and secondary outcome was central macular thickness (CMT). The patients were followed for 6 months. Results: Mean BCVA changes up to 4 and 6 months were insignificant in both groups. It changed from 0.72 ± 0.56 logMAR at baseline to 0.74 ± 0.5 (P = 0.85) and 0.71 ± 0.44 (P = 0.40) in the combination group and from 0.48 ± 0.39 logMAR to 0.47 ± 0.35 (P = 0.48) and 0.52 ± 0.33 (P = 0.69) in the IVB alone group, at 4 and 6 months, respectively. The difference of mean BCVA changes between the groups was insignificant at both 4 and 6 months (P = 0.07 and P = 0.36, respectively). Within the group changes of mean CMT were significant only in the combination group at 4 and 6 months, from 518 ± 134 μ at baseline to 472 ± 151 to 475 ± 167 μ, respectively (P = 0.01 and P = 0.05). Corresponding changes were not significant in the IVB alone group. However, the difference between the groups was not significant at all visits (P = 0.51 and P = 0.71, respectively). Conclusions: This clinical trial demonstrated that intravitreal erythropoietin had no additional effect to IVB in the treatment of refractory DME in the short term. Trial registration: Clinical trials.gov identifier: NCT03821168 [ABSTRACT FROM AUTHOR]