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  • Author: Guo-zheng Yan x
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Yan-Ming Wang, Wen-Zheng Wang, Zhen-Lu Shao, De-Ming Wang and Guo-Qing Shi

Abstract

Coal spontaneous combustion is an extremely complicated physical and chemical changing process. In order to improve the indicator gases detection technology and coal spontaneous combustion monitoring, a novel forecast method for toxic gases emission from coal oxidation at low temperature is presented in this paper. The experiment system is setup combined with frequency-domain terahertz technology and coal temperature programming device. The concentration curves of carbon monoxide and sulphur dioxide gases from coal spontaneous combustion are estimated according to molecule terahertz spectra. The influences of coal rank and oxygen supply on coal spontaneous combustion characteristics are discussed. Both carbon monoxide and sulphur dioxide gases absorption spectra show the characteristic equi-spaced absorption peaks. Results demonstrate that under the condition of lean oxygen, there exists a critical oxygen concentration in the process of coal oxidation at low temperature. Comparing with Fourier infrared spectrum testing, the presented method is highly accurate and more sensitive, especially suitable for early-stage monitoring of the indicator gases produced by coal spontaneous combustion.

Open access

Zai-jun Xin, Xiu-zhen Li, Søren Nielsen, Zhong-zheng Yan, Yuan-qing Zhou, Yue Jia, Ying-ying Tang, Wen-yong Guo and Yong-guang Sun

Effect of Stubble Heights and Treatment Duration Time on the Performance of Water Dropwort Floating Treatment Wetlands (FTWS)

Floating treatment wetlands (FTWs) with Water Dropwort (Oenanthe javanica) were established in winter to investigate their potential role in the purification of eutrophicated water, and to identify the effects of different stubble heights of the Water Dropwort on the performance of the FTWs. The results of the experiments demonstrated: The Water Dropwort FTWs were effective in buffering the pH of the experimental water. The Water Dropwort FTWs were efficient in purifying eutrophicated water, with removal rate for total nitrogen (TN), total phosphorus (TP), ammonium nitrogen (NH4 + - N), and nitrate nitrogen (NO3 - - N) at 91.3, 58.0, 94.6, and 95.5% in the 15-day experiment, respectively. No significant difference in the purification effect was found among different stubble heights of Water Dropwort FTWs. Significant differences between the zero control and the FTWs were found for the removal of TP in the first 11 days; and for the removal of NH4 + - N in the first 4 days. No significant difference was found between the zero control and the FTWs for NO3 - - N in the first 4 days, but significant difference was detected after day 4. The optimum treatment duration time for the FTWs with Water Dropwort will depend on the nutrients to be removed. These results will provide basis for further application of the FTWs at large scale, as well as for future studies on the mechanism of nutrient removal process.

Open access

Ning Ma, Min Liu, Min Zheng, Xi Chen, Hong-yan Lu, Hong-guang Chen, Jun Zheng, Gui-ying Li, Juan Wang, Guo-wu Liu and Ning Wang

Abstract

Objective To estimate the HIV/AIDS epidemic and treatment demand and predict the situation in the next five years with Spectrum.

Methods Using Spectrum (version:3.54) to estimate the number of new HIV infections, number of people living with HIV, need for ART in adults and children, need for PMTCT and cotrimoxazole in Beijing and Hunan Province. Data used in the model including high-risk populations monitoring data and demographic information, was collected from Beijing Center for Disease Control and Prevention, Hunan Center for Disease Control and Prevention and extracted from statistical yearbooks and published literatures.

Results Few new HIV/AIDS were reported in Beijing prior to 1994, however, the number of HIV infections was increasing rapidly from 1995 to 2008, and decreased after that, increased rapidly again after 2012. The number of patients who need antiretroviral treatment was increasing among the group aged between 15-49 years with young patients aged 15-24 years peaked in 2010 and decreased rapidly after that. Few HIV-infected patients were reported before 1997 in Hunan Province, and the number of new infections was increasing rapidly since 1998. The number of patients who need antiretroviral treatment was increasing among the group aged between 15 - 49 years since 2000 with young patients aged 15-24 years in need of antiretroviral therapy increasing continuously.

Conclusions After HIV infection was first founded in Beijing and Hunan Province, there was a slow growth and then a rapid growth of HIV epidemic. According to prediction of Spectrum, the demand for antiretroviral therapy in Beijing would begin to decline since 2011, meanwhile, the HIV epidemic in Hunan Province would enter a rapid growth period with the demand for antiviral therapy continuing to increase. In this study, Spectrum was applied to estimate the HIV epidemic situation and need for treatment in the next five years in Beijing and Hunan Province. It provides the basis for health resource allocation and policy formulation of HIV management.