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  • 1
    Electronic Resource
    Electronic Resource
    s.l. ; Stafa-Zurich, Switzerland
    Key engineering materials Vol. 336-338 (Apr. 2007), p. 1124-1126 
    ISSN: 1013-9826
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: In this paper, microspheres were prepared by using Chinese bauxite as raw materials throughcentrifugal spray drying method. The microstructure and composition of ceramic microsphere wereinvestigated by X-ray diffraction, scanning electron microscope and X-ray energy spectrum. The particlesize was 10~100#m. The XRD analysis reveals that the main crystalline phase of the ceramic microspherewere α-Al2O3 and mullite (3Al2O3•2SiO2). The Al2O3 content (chemical composition) of the microsphereswas little more than 70%, and the molar ratio of Al2O3/SiO2 was near to the molar ratio of aluminaand silica of mullite
    Type of Medium: Electronic Resource
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  • 2
    Publication Date: 2015-12-23
    Description: ABSTRACT Temporal and spatial variations in reference evapotranspiration (ET 0 ) from 1980 to 2012 were investigated for 33 meteorological stations in the three-river source region (TRSR). Penman–Monteith reference evapotranspiration in the TRSR significantly decreased at a rate of 0.91 mm a −2 from 1980 to 2012, and the decrease was actually an offset of the positive effect of increasing air temperature on ET 0 and the negative effect of decreasing net radiation, wind speed, and actual vapor pressure. A differential equation method based on the Penman–Monteith formula was used to attribute the change in ET 0 . As for the decrease of reference evapotranspiration from 1980 to 2012, the contributions of net radiation, wind speed, actual vapor pressure, and air temperature were −0.57, −0.49, −0.26, +0.41 mm a −2 , respectively. Thus, ‘net radiation decrease’ was the major reason for the decrease in ET 0 for the TRSR. In addition, it appears that the change in ET 0 was more sensitive to meteorological variables in high-elevation regions than in low-elevation regions.
    Print ISSN: 0899-8418
    Electronic ISSN: 1097-0088
    Topics: Geosciences , Physics
    Published by Wiley
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  • 3
    Publication Date: 2015-06-11
    Description: Pan evaporation is an important indicator of atmospheric evaporative demand and its long-term variation is of much concern in studies of climate change. Based on data from 33 meteorological stations from 1962 to 2012, this work considered the temporal and spatial trends of pan evaporation and the meteorological variables that affect them in the Three-River Source Region (TRSR) of southwestern China. Pan evaporation in the TRSR has decreased significantly since 1988 with an obvious abrupt change from 1993 to 2003. Furthermore, a 27-year period of oscillation has existed over the past 51 years. Pan evaporation reflects the combined effects of four meteorological variables: net radiation ( R n ), wind speed ( u 2 ), actual vapor pressure ( e a ), and air temperature ( T a ). Based on this research a number of conclusions were drawn. (1) The pace of climate change increased after 1980 and pan evaporation decreased at a rate of −13.3 mm/a 2 from 1980 to 2012, which is much faster than the rate of −1.2 mm/a 2 from 1962 to 1979. (2) For the decrease of pan evaporation from 1980 to 2012, the quantifying contributions of R n , u 2 , e a , and T a were −8.7, −6.4, −1.8, and +3.6 mm/a 2 , respectively. Thus, it was established for the TRSR that “global dimming” was the main reason and “wind stilling” was a close second to “global dimming” for the decrease in pan evaporation. (3) Different regions of the TRSR are affected differently by the effects of the meteorological variables. Low-elevation regions in the TRSR are more susceptible to the effects of net radiation and wind speed, whereas high-elevation regions are affected more by actual vapor pressure and air temperature.
    Print ISSN: 0148-0227
    Topics: Geosciences , Physics
    Published by Wiley on behalf of American Geophysical Union (AGU).
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  • 4
    Publication Date: 2015-01-20
    Description: Background: Smoking has resulted in numerous deaths in China. Data indicate that 21% of college students in China are smokers. Objective: This study aimed to examine the smoking-related behaviors of undergraduates, as influenced by knowledge, attitude, social pressure, and environmental constraints. Method: A convenience sampling of 412 fresh undergraduates from two universities in the University Town in Chongqing, China was recruited. Chi-square tests were used to compare the smoking-related variables between smokers and non-smokers. Moreover, logistic regression was used to examine the factors that associated with smoking status in undergraduates. Results: Smokers and non-smokers differ in terms of knowledge, attitudes toward smoking, participation in tobacco promotional activities, and sources of social pressure. Logistic regression model identified that sex, living cost, five smoking-related attitudes of “Smoking is pleasurable, Smoking relaxes me, Smoking makes me look strong, Smoking is a waste of money, Smoking can help me study better”, the social pressure “Smoking brings comfort during celebration”, and the environmental constraints “How did you get your cigarettes in the past 30 days?” are significantly associated with smoking. Conclusions: The findings provide a better understanding of the epidemic of smoking among fresh undergraduates in Chongqing, China. This study provides more detailed consideration of the implications for the WHO Framework Convention on Tobacco Control (FCTC) policies, especially on restriction of retail sales outlets and tobacco promotion activities near universities in China.
    Print ISSN: 1661-7827
    Electronic ISSN: 1660-4601
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Medicine
    Published by MDPI Publishing
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  • 5
    Publication Date: 2016-02-24
    Description: Groundwater has always been a valuable resource in Beijing, facing a great decline of groundwater level during the past decades. However, few previous researches have revealed the spatial variation of groundwater level within Beijing Plain. In this study, spatiotemporal variation of groundwater level from 2001 to 2010 in Beijing Plain has been investigated. Factor analysis has been conducted to identify the primary influencing factor. Results showed that the groundwater level decreased by 8.41 m from 2001 to 2010, with a linear decreasing rate of 0.954 m per year averagely. Significant spatial variation characteristics have been detected. The north area suffered more groundwater depletion than the south part in general. The lowest groundwater level has been identified downstream Miyun Reservoir, central part of the Plain. Nevertheless, the most of the south part witnessed a slight revival between 2001 and 2010. This may be due to the differences of socioeconomic circumstances in the Plain. Three influencing factors, that is, “demand factor,” “supply factor,” and “loss factor,” have been identified in the water balance model. Eigenvalues of these factors are 3.563, 2.910, and 1.632, respectively, indicating that these factors influenced the groundwater system to various extents, with the demand factor being the primary one.
    Print ISSN: 1687-9309
    Electronic ISSN: 1687-9317
    Topics: Geosciences , Physics
    Published by Hindawi
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  • 6
    Publication Date: 2019
    Description: As the penetration of intermittent renewable energy increases and unexpected market behaviors continue to occur, new challenges arise for system operators to ensure cost effectiveness while maintaining system reliability under uncertainties. To systematically address these uncertainties and challenges, innovative advanced methods and approaches are needed. Motivated by these, in this paper, we consider an energy integrated system with renewable energy and pumped-storage units involved. In addition, we propose a data-driven risk-averse two-stage stochastic model that considers the features of forbidden zones and dynamic ramping rate limits. This model minimizes the total cost against the worst-case distribution in the confidence set built for an unknown distribution and constructed based on data. Our numerical experiments show how pumped-storage units contribute to the system, how inclusions of the aforementioned two features improve the reliability of the system, and how our proposed data-driven model converges to a risk-neutral model with historical data.
    Electronic ISSN: 1996-1073
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Published by MDPI
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  • 7
    Publication Date: 2019
    Description: Water-rights trade has proved to be an effective method for coping with water shortages through the transfer of water resources between users. The water allocation system is classified into two categories based on information transparency and water rights transaction goals: administered system (AS) and market-based system (MS). A multi-agent and multi-objective optimal allocation model, built on a complex adaptive system, was introduced to direct the distribution of water resources under an AS in the Shiyang River Basin; it was compared with a market-based water rights transaction model using the bulletin-board approach. Ideal economic agent equations played a dominant role in both models. The government and different water users were conceptualized as agents with different behaviors and goals in water allocation. The impact of water-saving cost on optimal water allocation was also considered. The results showed that an agent’s water-saving behavior was incentivized by high transaction prices in the water market. Under the MS, the highest bid in the quotation set had a dominant influence on how trade was conducted. A higher transaction price will, thus, result in a better benefit ratio, and a lower one will result in inactivity in terms of water rights trade. This will significantly impact the economic benefit to the basin.
    Electronic ISSN: 2073-4441
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Published by MDPI
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  • 8
    Publication Date: 2018
    Description: With the implementation of the Grain for Green Project, the apple plantation area is increasing in Loess Plateau. However, due to severe water scarcity, the sustainability of apple tree growth is threatened. In this paper, we used meteorological data (1990–2013) and forecasted climate data (2019–2050) to estimate water demand and establish a water suitability model to study the water balance between available water and water consumption of the apple trees. The results show that: (i) the order of the average water demand of apple plantation in each subarea is Shaanxi Province 〉 Yuncheng area 〉 Gansu Province 〉 Sanmenxia Region, ranging from 500 to 950 mm; (ii) the temporal variability of water suitability from 1990 to 2013 is large, and the higher values are concentrated in the late growth stage of the apple trees and the lower values are concentrated in the early growth stage; (iii) the temporal and spatial distribution of water suitability is relatively stable and even in the Loess Plateau in the period of 2019–2050; (iv) the water suitability is mainly affected by effective precipitation and reference evapotranspiration and the reference evapotranspiration is mainly affected by the solar radiation (36%) and average temperature (38%). Furthermore, due to the joint influence of precipitation increases and solar radiation (average temperature) increases, the future water suitability of the apple plantation area in the Loess Plateau is showing a non-significant downward trend under RCP4.5 scenario.
    Print ISSN: 1661-7827
    Electronic ISSN: 1660-4601
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Medicine
    Published by MDPI
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  • 9
    Publication Date: 1997-06-01
    Print ISSN: 1046-5928
    Electronic ISSN: 1096-0279
    Topics: Biology , Medicine
    Published by Elsevier
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