252 research outputs found

    Dynamic stochastic joint expansion planning of power systems, natural gas networks, and electrical and natural gas storage

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    Over the last decades, electricity generation from natural gas has substantially increased, mostly driven by low natural gas prices due to fracturing and lower extraction costs. The geographic distance between natural gas resources and load centers calls for a holistic tool for joint expansion of power systems and natural gas networks. In this paper, a Dynamic Stochastic Joint Expansion Planning (DSJEP) of power systems and natural gas networks is proposed to minimize the investment and operational costs of power and natural gas systems. Electrical and natural gas storage (ENGS) are considered as an option for decision-makers in the DSJEP problem. The proposed approach takes into account long-term uncertainties in natural gas prices and electric and natural gas demands through scenario realizations. In dynamic planning, more scenario needs more time for computation; therefore, scenario reduction is implemented to eschew unnecessary scenarios. The proposed formulation is implemented on a four-bus electricity system with a five-node natural gas network. To demonstrate the efficiency and scalability of the proposed approach, it is also tested on the IEEE 118-bus system with a 14-node natural gas network. The numerical results demonstrate that ENGS can reduce the total investment cost, up to 52% in the test cases, and operational cost, up to 3%. In this paper, co-planning of power and natural gas systems considering natural gas and electrical storage is represented. Also, electrical and natural gas load growth uncertainties are taken into account to model the real situations. The purpose of the model is to minimize investing and operational costs

    CRUSTAL DEFORMATION IN NW IRAN: INSIGHTS FROM DIFFERENT INVARIANT AND VARIANT COMPONENTS OF GEODETIC STRAIN RATE TENSORS

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    Northwest of Iran, as a tectonically active region, has experienced numerous devastating earthquakes. That is why it is so important to study the earth deformation in this area and to provide more precise insights. So far, most researchers have had the preference of using the invariant component of strain rate tensor for investigating the Earth's shape deformation in the region. However, to examine the efficiency of the variant components of the geodesic strain rate tensor in interpreting deformations of north-western Iran, we have in this article maps of variant components of the geodetic strain rate tensor (normal strain rate along north and eastbound). Using the velocity field gathered from a previous article, and also using a simple and straightforward method, the strain rate tensors were calculated. The obtained contraction along the north direction (from the normal strain along this axis) confirms the Eurasia-Arabia collision. Besides, the obtained extension along the east direction and the derived expansion of the dilatation, show the effect of Anatolian motion to the west and eastward movement of the central Iran plateau on the tectonic structure of the studied area. These two results showed that the variant component of strain rate tensor also provides us with useful information about a region shape deformation

    Effects of intermittent feeding on compensatory growth, feed intake and body composition in Asian sea bass (Lates calcarifer)

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    This experiment was conducted to investigate the effects of various starvation and refeeding periods on growth, feed utilization and body composition in Asian sea bass (Lates calcarifer) with an average initial weight of 30.26±1.4 g (mean±SE). The fish were exposed to three different regimes: the control group fed twice daily to apparent satiation throughout the experiment (C), the first group starved for 4 days and refed for 16 days, this cycle was repeated two times (T1) and the second group starved for 8 days and refed for 32 days (T2). At the end of experiment, there were not any significant differences in growth and feeding performance among different treatments (p>0.05). Daily feed intake was significantly higher in the deprived fish than in the control fish (p0.05). Starvation had a significant effect on protein content on one sampling date during the experimental period; protein content in T2 on day 8 was significantly lower compared to the control (p<0.05). Sea bass showed complete compensation indicating a high ability of the deprived fish to grow sufficiently to fully compensate for weight loss during starvation. The results suggested that the feeding schedule involving starvation-refeeding cycles could be a promising feed management option for the culture of this species

    The Janus Nature of Human Rights in Iran: Understanding Progress and Setbacks on Human Rights Protections since the Revolution

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    There have been serious concerns raised both internally and externally about human rights violations in Iran over the past 30 years. Is there any reason to believe there will be an improvement in the protection of human rights in the future? Risse and Sikkink have suggested that states can be socialized to improve at least part of their human rights record. They argue that Western states, advocacy networks, and international norms can have a positive impact on rights of personal integrity in most if not all non-Western developing countries. Will Iran be socialized to improve its human rights record? This chapter examines both the progress on and the violations of human rights in Iran over the past 30 years. I want to explain why the Islamic regime has restricted the basic rights of its citizens, as well as what accounts for the progress made on some second generation rights. To see further improvements in the protection of human rights this chapter suggests that minimizing threats is a necessary step for further progress. Therefore, this chapter examines Iran’s human rights record in the framework of the interplay of international human rights norms and perceived threats

    Measurement of peripheral dose to the pelvic region and the associated risk for cancer development after breast intraoperative electron radiation therapy

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    This study aimed to measure the received dose to the pelvic region of patients during breast intraoperative electron radiation therapy (IOERT). Furthermore, we compared the findings with those of external beam radiation therapy. Finally, secondary ovarian and uterus cancer risks following breast IOERT were estimated. In the current study, the received dose to the pelvic surface of 18 female patients during breast IOERT boosts were measured by thermoluminescent dosimeter (TLD-100) chips. All patients were treated with 12 Gy given in a single fraction. To estimate the dose to the ovary and uterus of the patients, conversion coefficients for depth from the surface dose were obtained in a Rando phantom. Given the received dose to the pelvic region of the patients, secondary ovarian and uterus cancer risks following breast IOERT were estimated. The received doses to the ovary and uterus surface of the patients were 0.260 ±0.155 mGy to 31.460 ±6.020 mGy and 0.485 ±0.122 mGy to 22.387 ±15.476 mGy, respectively. Corresponding intra-pelvic (ovary and uterus) regional doses were 0.012 ±0.007 mGy to 1.479 ±0.283 mGy and 0.027 ±0.001 mGy to 1.164 ±0.805 mGy, respectively. Findings demonstrated that the ratio of the received dose by the pelvic surface to the regional dose during breast IOERT was much less than external beam radiation therapy. The mean of the secondary cancer risks for the ovary in 8 and 10 MeV electron beam energies were 135.722 ±117.331 �10 -6 and 69.958 ±28.072 �10 -6 , and for the uterus were 17.342 ±10.583 �10 -6 and 2.971 ±3.604 �10 -6 , respectively. According to our findings, the use of breast IOERT in pregnant patients can be considered as a safe radiotherapeutic technique, because the received dose to the fetus was lower than 50 mGy. Furthermore, IOERT can efficiently reduce the unnecessary dose to the pelvic region and lowers the risk of secondary ovarian and uterus cancer following breast irradiation. © 2019 Society for Radiological Protection. Published on behalf of SRP by IOP Publishing Limited. All rights reserved

    Differential scanning calorimetry (DSC) and thermodynamic prediction of liquid fraction vs temperature for two high-performance alloys for semi-solid processing (Al-Si-Cu-Mg (319s) and Al-Cu-Ag (201))

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    There is a need to extend the application of semi-solid processing (SSP) to higher performance alloys such as 319s (Al-Si-Cu-Mg) and 201 (Al-Cu-Ag). The melting of these two alloys was investigated using differential scanning calorimetry (DSC) and thermodynamic prediction. The alloys had been processed by magneto-hydrodynamic (MHD) stirring before receipt to produce a microstructure suitable for SSP. The DSC results for the as-received MHD material were compared with those for material which has been taken through a complete DSC cycle and then reheated for a second DSC run. The effects of microsegregation were then analyzed. A higher liquid fraction for a particular temperature is found in the second DSC run than the first. Microstructural observations suggest this is because the intermetallics which form during the first cooling cycle tend to co-located. Quaternary and ternary reactions then occur during the second DSC heat and the co-location leads to enhanced peaks. The calculated liquid fraction is lower with 10 K/min DSC heating rate comparing with 3 K/min at a given temperature. The DSC scan rate must therefore be carefully considered if it is to be used to identify temperature parameters or the suitability of alloys for SSP. In addition, the starting material for DSC must represent the starting material for the SSP. With thermodynamic prediction, the equilibrium condition will provide better guidance for the thixoforming of MHD stirred starting material than the Scheil condition. The Scheil mode approximates more closely with a strongly microsegregated state

    Grain refinement of Al-Mg-Sc alloy by ultrasonic treatment

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    In foundry practice, ultrasonic treatment has been used as an efficient technique to achieve grain refinement in aluminium and magnesium alloys. This article shows the strong effect of pouring temperature and ultrasonic treatment at various temperatures on the grain refinement of Al-1 wt% Mg-0.3 wt% Sc alloy. Without ultrasonic treatment, a fine grain structure was obtained at the pouring temperature of 700 °C. The average grain size sharply decreases from 487 ± 20 to 103 ± 2 μm when the pouring temperature decreases from 800 to 700 °C. Ultrasonic vibration proved to be a potential grain refinement technique with a wide range of pouring tem- perature. A microstructure with very fine and homogeneous grains was obtained by applying ultrasonic treatment to the melt at the temperature range between 700 and 740 °C, before pouring. Cavitation-enhanced hetero- geneous nucleation is the mechanism proposed to explain grain refinement by ultrasound in this alloy. Moreover, ultrasonic treatment of the melt was found to lead to cast samples with hardness values similar to those obtained in samples submitted to precipitation hardening, suggesting that ultrasonic treatment can avoid carrying out heat treatment of cast parts.This research was supported by The Project Bridging The Gap, funded by the Erasmus Mundus External Cooperation Window Programme. Acknowledgements also to the University of Minho, for the provision of research facilities

    Anti- Japanese-Encephalitis-Viral Effects of Kaempferol and Daidzin and Their RNA-Binding Characteristics

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    Background: New therapeutic tools and molecular targets are needed for treatment of Japanese encephalitis virus (JEV) infections. JEV requires an a-1 translational frameshift to synthesize the NS1 ’ protein required for viral neuroinvasiveness. Several flavonoids have been shown to possess antiviral activity in vitro against a wide spectrum of viruses. To date, the antiviral activities of flavonol kaempferol (Kae) and isoflavonoid daidzin (Dai) against JEV have not been described. Methodology/Principal Findings: The 50 % cytotoxic concentration (CC50) and 50 % effective concentration (EC50) against JEV were investigated in BHK21 cells by MTS reduction. Activity against viral genomic RNA and proteins was measured by real-time RT-PCR and western blotting. The frameshift site RNA-binding characterization was also determined by electrospray ionization mass spectrometry, isothermal titration calorimetry and autodocking analysis. EC 50 values of Kae and Dai were 12.6 and 25.9 mM against JEV in cells pretreated before infection, whereas in cells infected before treatment, EC50 was 21.5 and 40.4 mM, respectively. Kae exhibited more potent activity against JEV and RNA binding in cells following internalization through direct inhibition of viral replication and protein expression, indicating that its antiviral activity was principally due to direct virucidal effects. The JEV frameshift site RNA (fsRNA) was selected as a target for assaying Kae and Dai. ITC of fsRNA revealed an apparent Kb value for Kae that was nine fold stronger than that for Dai. This binding was confirmed and localized to the RNA using ESI-MS and autodock analysis. Kae could form non-covalent complexes wit
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