1,043 research outputs found

    Effect of different carrier gases on productivity enhancement of a novel multi-effect vertical concentric tubular solar brackish water desalination device

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    A novel multi-effect vertical concentric tubular solar brackish water desalination device is introduced in present study. The device consists of four closely spaced concentric pipes, in which the feed water gets preheated by hot brine water to guarantee the evaporation efficiency. An experimental investigation and analytical analysis were carried out to signify the effect of carrier gas-water vapor mixture on productivity enhancement of the device. Different carrier gases were used in the performance evaluation: carbon dioxide, helium, nitrogen, oxygen, air and argon. The water yield and the top/bottom temperature values of condensation surface of the device with different carrier gases were tested. In addition, the present investigation is presented an approach to predict the theory yield based on the internal heat and mass transfer mechanism. The experimental results indicate that, when the heating temperature is 80 °C and the carrier gas is helium, the water productivity rate can reach to 1.19 kg/h. It is increased by 30.76% than the carrier gas of air. The numerical results had been calculated and a consistent agreement with the experimental results had been obtained of different operation temperatures. The Dv under different heating temperature were obtained according to the experimental results

    Modeling of imbalance in differential lines targeted to SPICE simulation

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    partially_open5siIn this paper, a SPICE model representative for the mode conversion occurring in differential lines affected by imbalance either of the line cross-section and the terminal networks is developed. The model is based on the assumption of weak imbalance and allows approximate prediction of modal quantities, through separate modeling of the contributions due to line and termination imbalance by controlled sources with (possibly) frequency dependent gain. The proposed SPICE model is used to perform worst-case prediction of undesired modal voltages induced at line terminals by mode conversion.openGrassi, Flavia; Wu, Xinglong; Yang, Yuehong; Spadacini, Giordano; Pignari, Sergio A.Grassi, Flavia; Wu, Xinglong; Yang, Yuehong; Spadacini, Giordano; Pignari, SERGIO AMEDE

    The study of a seasonal solar cchp system based on evacuated flat-plate collectors and organic rankine cycle

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    The demands of cooling, heating and electricity in residential buildings are varied with seasons. This article presented a seasonal solar combined cooling heating and power (CCHP) system based on evacuated flat-plate collectors and organic Rankine cycle. The heat collected by evacuated flat-plate collectors is used to drive the organic Rankine cycle unit in spring, autumn and winter, and drive the double-effect lithium bromide absorption chiller in summer. The organic Rankine cycle condensation heat is used to yield hot water in spring and autumn, whereas supply heating in winter. The system thermodynamic performance was analyzed. The results show that the system thermal efficiency in spring, autumn and winter, ηsys, I, increases as organic Rankine cycle evaporation temperature, T6, and evacuated flat-plate collectors outlet temperature, T2, decrease. The maximum ηsys, I of 67.0% is achieved when T6 = 80 °C and T2 =100 °C. In summer, the system thermal efficiency, ηsys, II, increases first and then decreases with the increment of T2. The maximum ηsys, II of 69.9% is obtained at T2 =136 °C. The system output performance in Beijing and Lanzhou is better than that in Hefei. The average output power, heating capacity, hot water and cooling capacity are 50-72 kWh per day, 989-1514 kWh per day, 49-57 ton per day and 1812-2311 kWh per day, respectively. The system exergy efficiency increases from 17.8-40.8% after integrating the organic Rankine cycle unit

    A Critical Review of Sustainable Energy Policies for the Promotion of Renewable Energy Sources

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    Meeting the rising energy demand and limiting its environmental impact are the two intertwined issues faced in the 21st century. Governments in different countries have been engaged in developing regulations and related policies to encourage environment friendly renewable energy generation along with conservation strategies and technological innovations. It is important to develop sustainable energy policies and provide relevant and suitable policy recommendations for end-users. This study presents a review on sustainable energy policy for promotion of renewable energy by introducing the development history of energy policy in five countries, i.e., the United States, Germany, the United Kingdom, Denmark and China. A survey of the articles aimed at promoting the development of sustainable energy policies and their modelling is carried out. It is observed that energy-efficiency standard is one of the most popular strategy for building energy saving, which is dynamic and renewed based on the current available technologies. Feed-in-tariff has been widely applied to encourage the application of renewable energy, which is demonstrated successfully in different countries. Building energy performance certification schemes should be enhanced in terms of reliable database system and information transparency to pave the way for future net-zero energy building and smart cities

    Small-scale fluctuation and scaling law of mixing in three-dimensional rotating turbulent Rayleigh-Taylor instability

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    The effect of rotation on small-scale characteristics and scaling law in the mixing zone of the three-dimensional turbulent Rayleigh-Taylor instability (RTI) is investigated by the lattice Boltzmann method at small Atwood number. The mixing zone width h ( t ) , the root mean square of small scale fluctuation, the spectra, and the structure functions are obtained to analyze the rotating effect. We mainly focus on the process of the development of plumes and discuss the physical mechanism in the mixing zone in rotating and nonrotating systems. The variation of kinetic energy spectra E u and temperature energy spectra E θ with the dimensionless rotation Ω τ demonstrate the suppression effect of rotation. Two scaling laws between the mixing layer width h ( t ) and dimensionless time t / τ are obtained at various Coriolis forces( √ h ( t ) ≃ t 0.9 and √ h ( t ) ≃ t 0.35 ). The rotation increasingly suppresses the growth of the mixing layer width h ( t ) . The velocity and temperature fluctuations are also suppressed by the rotation effect. The relation between the Nusselt number (Nu) and the Rayleigh number (Ra) indicates that the heat transfer is suppressed by the rotation effect in the rotating RT system. The width of the inertial subrange increasingly narrows with increasing Ω τ

    Activation of hedgehog signaling is not a frequent event in ovarian cancers

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    The hedgehog (Hh) signaling pathway regulates many processes of development and tissue homeostasis. Activation of hedgehog signaling has been reported in about 30% of human cancer including ovarian cancer. Inhibition of hedgehog signaling has been pursued as an effective strategy for cancer treatment including an ongoing phase II clinical trial in ovarian cancer. However, the rate of hedgehog signaling activation in ovarian cancer was reported differently by different groups. To predict the successful for future clinical trials of hedgehog signaling inhibitors in ovarian cancer, we assessed hedgehog pathway activation in 34 ovarian epithelial tumor specimens through analyses of target gene expression by in-situ hybridization, immunohistochemistry, RT-PCR and real-time PCR. In contrast to previous reports, we only detected a small proportion of ovarian cancers with hedgehog target gene expression, suggesting that identification of the tumors with activated hedgehog signaling activation will facilitate chemotherapy with hedgehog signaling inhibitors

    Heavy Flavour Physics and CP Violation at LHCb: a Ten-Year Review

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    Heavy flavour physics provides excellent opportunities to indirectly search for new physics at very high energy scales and to study hadron properties for deep understanding of the strong interaction. The LHCb experiment has been playing a leading role in the study of heavy flavour physics since the start of the LHC operations about ten years ago, and made a range of high-precision measurements and unexpected discoveries, which may have far-reaching implications on the field of particle physics. This review highlights a selection of the most influential physics results on CP violation, rare decays, and heavy flavour production and spectroscopy obtained by LHCb using the data collected during the first two operation periods of the LHC. The upgrade plan of LHCb and the physics prospects are also briefly discussed.Comment: Invited review for Frontiers of Physic

    Inhibition of Aldose Reductase Activates Hepatic Peroxisome Proliferator-Activated Receptor-α and Ameliorates Hepatosteatosis in Diabetic db/db Mice

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    We previously demonstrated in streptozotocin-induced diabetic mice that deficiency or inhibition of aldose reductase (AR) caused significant dephosphorylation of hepatic transcriptional factor PPARα, leading to its activation and significant reductions in serum lipid levels. Herein, we report that inhibition of AR by zopolrestat or by a short-hairpin RNA (shRNA) against AR caused a significant reduction in serum and hepatic triglycerides levels in 10-week old diabetic db/db mice. Meanwhile, hyperglycemia-induced phosphorylation of hepatic ERK1/2 and PPARα was significantly attenuated in db/db mice treated with zopolrestat or AR shRNA. Further, in comparison with the untreated db/db mice, the hepatic mRNA expression of Aco and ApoA5, two target genes for PPARα, was increased by 93% (P < 0.05) and 73% (P < 0.05) in zopolrestat-treated mice, respectively. Together, these data indicate that inhibition of AR might lead to significant amelioration in hyperglycemia-induced dyslipidemia and nonalcoholic fatty liver disease

    The mass transfer coefficient assessment and productivity enhancement of a vertical tubular solar brackish water still

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    This paper presents an experimental investigation of a single-effect vertical tubular solar brackish water desalination device, with an aim to determine the mass transfer coefficient and its enhancement. The device consists of two closely spaced concentric pipes. The outside of the inner pipe is covered with a wicking material and wetted with hot brackish water. The water vapor evaporated from the wicking material condenses on the inside of the outer pipe. The measured productivity and temperatures at various points are given for different wicking materials thickness, water flow rates and chamber pressure under the condition of given heating power. Mass transfer coefficients are calculated from the experimental results and then applied in the prediction of water productivity. The maximum discrepancy between the calculation yield and measurement yield is relatively small compared with previous study. In addition, it was found that the yield of the solar still is 23.9% higher when the chamber pressure is lower by 25 kPa due to the enhanced mass transfer. Similar, doubling the ambient air velocity can increase the water yield by about 17.0%

    Video-Assisted Informed Consent for Cataract Surgery: A Randomized Controlled Trial

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    Purpose. To investigate whether adding video assistance to traditional verbal informed consent advisement improved satisfaction among cataract surgery patients. Methods. This trial enrolled 80 Chinese patients with age-related cataracts scheduled to undergo unilateral phacoemulsification surgery. Patients were randomized into two groups: the video group watched video explaining cataract-related consent information and rewatched specific segments of the video at their own discretion, before receiving traditional verbal consent advisement; the control group did not watch the video. Outcomes included patient satisfaction, refusal to consent, time to complete the consent process, and comprehension measured by a ten-item questionnaire. Results. All 80 enrolled patients signed informed consent forms. Compared with the control group, members of the video group exhibited greater satisfaction (65% versus 86%, p=0.035) and required less time to complete the consent process (12.3±6.7 min versus 5.6±5.4 min, p<0.001), while also evincing levels of comprehension commensurate with those reported for patients who did not watch the video (accuracy rate, 77.5% versus 80.2%, p=0.386). Conclusion. The video-assisted informed consent process had a positive impact on patients’ cataract surgery experiences. Additional research is needed to optimize patients’ comprehension of the video
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