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• Effects of vortex generator on subcooled flow boiling are investigated. • Vortex generator accelerates the bubble departure from the heating surface. • The maximum increase of the heat transfer coefficient by vortex generator is 8.4×103 W m-2 K-1. • A new correlation targeting vortex-enhanced subcooled flow boiling is developed. Subcooled flow boiling in a micro-channel is a mainstream heat dissipation way for high-heat-flux electronics. This paper presents a new idea to enhance heat transfer of subcooled flow boiling, i.e. accelerating bubble departure from the heating wall of flow channel by inserting a vortex generator; and the effects of vortex generator positions and working fluid conditions on the heat transfer characteristics are experimentally studied. The shape of the vortex generator is helix with the length, pitch, helix diameter and wire diameter of 22.5 mm, 1.8 mm, 1.8 mm and 0.2 mm, respectively. The vortex generator positions in the experiments include the front, the middle and the end of the flow channel; and the working fluid conditions include the mass fluxes of 1000 – 3500 kg m−2 s−1 and the inlet subcooling degrees of 30–50 K. It is found that the vortex generator could accelerate the bubble departure from the wall, and thus enhance the heat transfer in subcooled flow boiling. The maximum increase of the heat transfer coefficient of the all vortex channel is 8.4 × 103 W m−2 s−1, and the maximum increase rate of critical heat flux (CHF) is 21.8%. Furthermore, a new correlation to predict the heat transfer coefficients of vortex enhanced subcooled flow boiling was developed. The predictions by the new correlation could agree with 92% of the experimental data within a deviation of ± 30%, and the average deviation is 13.7%. [ABSTRACT FROM AUTHOR]

This study aimed to examine the effects of amlodipine and atorvastatin alone or in combination on the regulation of inflammatory cytokines and the underlying mechanisms in elderly spontaneously hypertensive (SH) rats. The level of serum hs-CRP was detected with ELISA. The serum TNF-α and IL-1β levels were assessed by radioimmunity assay (RIA). Cardiac inflammatory cell infiltration was observed by HE staining. The protein levels of TNF-α, IL-1β, of NF-κB P65 and IκBα were detected by immunoblotting. The intracellular localization of NF-κB p65 was observed using immunohistochemistry. Amlodipine or atorvastatin obviously ameliorated the myocardial inflammatory cell infiltration in SH rats, which was further improved by combinatorial treatment with amlodipine and atorvastatin. Either amlodipine or atorvastatin decreased plasma IL-1β content in SH rats, but there was no significant difference when compared with untreated SH rats. However, the combination of amlodipine and atorvastatin significantly decreased plasma IL-1β level in SH rats. Moreover, amlodipine or atorvastatin intervention significantly reduced myocardial TNF-α and IL-1β protein levels in SH rats, which was further suppressed by the combination of amlodipine and atorvastatin. In addition, amlodipine or atorvastatin inhibited the activity of NF-κB signaling in SH rats, which was further suppressed by combinatorial treatment. Furthermore, amlodipine or atorvastatin restored the activity of IκB-α in SH rats, which was enhanced by combinatorial treatment. Our results demonstrated amlodipine and atorvastatin improved ventricular hypertrophy and diastolic function possibly through the intervention of TNF-α, IL-1β, NF-κB/IκB inflammatory cytokine network. Our study suggests that amlodipine combined with atorvastatin may have additive effect on inhibiting inflammatory response. [ABSTRACT FROM AUTHOR]

Abstract A proactive fault detection and diagnosis (FDD) method is proposed for variable-air-volume (VAV) terminals in this study to overcome the problem of diagnostic information poor. The basic idea is to produce additional diagnostic information proactively through introducing specific disturbances to the suspected VAV terminal. The dynamic responses of the VAV terminal, which can be observed from the measurements and control signals, are helpful in isolating faults which are challenging for the conventional passive FDD methods. A list of proactive actions is designed to introduce the smallest disturbances into indoor environment. Therefore, the proposed method can work during office hours. Without loss of generality for practical applications, the proactive actions change the zone air temperature set-point only. The proposed method can be implemented in both building management systems and VAV terminal controllers. Evaluations are made on a simulated VAV system on Dymola platform. Results show that the method can improve FDD performance significantly. [ABSTRACT FROM AUTHOR]

• A quasi-three-dimensional model for performance of micro-channel SHP is developed. • Refrigerant flow among tubes is modeled as uneven flow with fixed direction in tube. • Air flow is modeled as uneven inlet flow with fixed direction across heat exchanger. • The model predicts micro-channel SHP heat capacity with average deviation below 5%. Micro-channel separated heat pipes (micro-channel SHPs), which may cycle without inputting additional electrical power, have shown their advantages of energy saving and compact structure, and they are preferred in the cooling of electronic equipment with narrow inner space. The non-uniformly distributed refrigerant flow among multiple flat tubes and air flow among multiple fins of micro-channel heat exchangers may have a significant effect on the performance of SHPs. In this study, a quasi-three-dimensional distributed parameter model of micro-channel SHPs is proposed for predicting the effects of non-uniformly distributed refrigerant and air flows on the performance. The model is developed by modeling all the components of a micro-channel SHP, i.e. an evaporator, an ascending tube, a condenser and a descending tube, respectively. In the model, the refrigerant flow is described as uneven flow among tubes and the flow direction is fixed inside each tube; the air flow is modelled as the flow with two-dimensional uneven distribution at the windward of heat exchanger and with the fixed direction across the heat exchanger; the three-dimensional partition method is applied to the control volume partition of flat tubes and fins. The proposed model is validated by experiments, and the results show that the deviations between simulated and experimental data of the heat transfer capacity, the temperature difference of micro-channel SHP, the outlet air temperature of evaporator and the outlet air temperature of condenser are 4.6%, 0.9 °C, 1.1 °C and 0.4 °C, respectively. [ABSTRACT FROM AUTHOR]