Based on the analysis of monitoring data on six pollution indexes of SO2, NO2, CO, O3, PM10 and PM2.5 from 53 monitoring points in 7 cities, including Beijing, Tianjin, Shijiazhuang, etc., from April 8 of 2014 to July...Based on the analysis of monitoring data on six pollution indexes of SO2, NO2, CO, O3, PM10 and PM2.5 from 53 monitoring points in 7 cities, including Beijing, Tianjin, Shijiazhuang, etc., from April 8 of 2014 to July 23 of 2014, this article adopted Pearson correlation coefficient method to determine the relevance among each pollutant of these cities with the help of SPSS. The results showed that such three leading indexes as SO2, PM10 and PM2.5 had strong correlation in Beijing, Tianjin and main cities of Hebei. Finally, some suggestions and preventive measures for the cooperative governance of air pollution in Beijing-Tianjin-Hebei Region were put forward, hoping this can help them.展开更多
Chromatography-mass spectrometry(GC-MS)was used to analyze the volatile components of cut tobacco samples with the help of heuristic evolving latent projections(HELP).After extracting with simultaneous distillation an...Chromatography-mass spectrometry(GC-MS)was used to analyze the volatile components of cut tobacco samples with the help of heuristic evolving latent projections(HELP).After extracting with simultaneous distillation and extraction method,the volatile components in cut tobacco were detected by GC-MS.Then the obtained original two-dimensional data were resolved into pure mass spectra and chromatograms.The qualitative analysis was performed by similarity searches in the national institute of standards and technology(NIST)mass database with the obtained pure mass spectrum of each component and the quantitative results were obtained by calculating the volume of total two-way response.The accuracy of qualitative and quantitative results were greatly improved by using the two-dimensional comprehensive information of chromatograms and mass spectra.107 of 141 separated constituents in the total ion chromatogram of the volatile components were identified and quantified,accounting for about 88.01% of the total content.The result proves that the developed method is powerful for the analysis of complex cut tobacco samples.展开更多
The purpose of the study is to generate traffic air information system) to determine a proper zone of AQMS (air analyzed were carbon monoxide (CO), and nitrogen oxides (NOx) pollution map using mathematical mode...The purpose of the study is to generate traffic air information system) to determine a proper zone of AQMS (air analyzed were carbon monoxide (CO), and nitrogen oxides (NOx) pollution map using mathematical model and GIS (geographic quality monitoring station) in municipality area. The pollutants which can be harmful to people living in the area. The three steps of mapping process were performed under the GIS environment using the existing vehicle emission rates and pollutant dispersion model. First, traffic volume, road network, and the emission rates of road segments varying with types of vehicle were collected from existing data. Second, the pollutant concentrations were calculated by use of CALINE4, a tool with Gaussian dispersion model. The model parameters include emission rate, wind directions and speeds, ambient temperature and observed pollutant concentration, and atmospheric stability during all seasons from the January 1, 2010 to May 31,2011 with regardless the rainy season. This resulted in concentrations at many receptor points along links of the road network. Third, distributions of pollution concentrations were generated by means of the spatial interpolation of those from receptors. The results of pollution raster-based maps are used for determining frequency of violence and combined pollution map. The resulting frequency of violence and intensity concentration will be further integrated to determine a potential area of AQMS. Finally, achieving pollution potential area of AQMS can be located as helpful basic data for efficient traffic and transportation planning.展开更多
Support vector regression (SVR) method is a novel type of learning machine algorithms, which is seldom applied to the development of urban atmospheric quality models under multiple socio-economic factors. This study...Support vector regression (SVR) method is a novel type of learning machine algorithms, which is seldom applied to the development of urban atmospheric quality models under multiple socio-economic factors. This study presents four SVR models by selecting linear, radial basis, spline, and polynomial functions as kernels, respectively for the prediction of urban dust fall levels. The inputs of the models are identified as industrial coal consumption, population density, traffic flow coefficient, and shopping density coefficient. The training and testing results show that the SVR model with radial basis kernel performs better than the other three both in the training and testing processes. In addition, a number of scenario analyses reveal that the most suitable parameters (insensitive loss function e, the parameter to reduce the influence of error C, and discrete level or average distribution of parameters σ) are 0.001, 0.5, and 2 000, respectively.展开更多
Inter-phase mass transfer is important to the design and performance of airlift loop reactors for either chemical or biochemical applications, and a good measurement technique is crucial for studying mass transfer in ...Inter-phase mass transfer is important to the design and performance of airlift loop reactors for either chemical or biochemical applications, and a good measurement technique is crucial for studying mass transfer in multiphase systems. According to the model of macro-scale mass transfer in airlift loop reactors, it was proved that the airlift loop reactor can be regarded as a continuous stirred tank reactor for measuring mass transfer coefficient. The calculated mass transfer coefficient on such a basis is different from the volumetric mass transfer coefficient in the macro-scale model and the difference is discussed. To describe the time delay of the probe response to the change of oxygen concentration in the liquid phase, a model taking into account the time constant of response is es-tablished. Sensitivity analysis shows that this model can be used to measure the volumetric mass transfer coefficient. Applying this model to the measurement of volumetric mass transfer coefficient in the loop reactor, results that co-incide with the turbulence theory in the literate were obtained.展开更多
Indoor Environmental Quality (IEQ) deals with providing a healthy and comfortable indoor environment. Most of international sustainability rating systems consider IEQ as a key perspective for developing sustainable ...Indoor Environmental Quality (IEQ) deals with providing a healthy and comfortable indoor environment. Most of international sustainability rating systems consider IEQ as a key perspective for developing sustainable buildings. Educational buildings include large number of people which increase the need to provide appropriate IEQ. Accordingly, there is a critical need to frequently assess of IEQ in this type of buildings in order to maintain the satisfactory level of IEQ. This paper aims to develop a framework for assessing and improving the IEQ of educational buildings in Saudi Arabia through measuring the IEQ parameters and integrating these results with Building Information Modeling (BIM). The key IEQ parameters considered in this study include thermal comfort, indoor air quality and visual comfort. These parameters have been measured by comfort-sense system, indoor air quality meter and light meter respectively. The measured data are integrated with BIM model in order to track the IEQ problems, and to develop IEQ history over time. By using the proposed framework, the IEQ can be tracked and improved. The IEQ assessment framework has been implemented on educational building in Saudi Arabia as a case study to validate the process and perform the necessary modifications and improvements.展开更多
It is a common issue in the processing industry of crayfish that flavored crayfish stored at room temperature is perishable.In order to establish an effective putrid prediction mechanism,high-throughput sequencing and...It is a common issue in the processing industry of crayfish that flavored crayfish stored at room temperature is perishable.In order to establish an effective putrid prediction mechanism,high-throughput sequencing and solid phase microextraction gas chromatography-mass spectrometry(SPME-GCMS)were used to analyse the microbial community structure and volatile flavor compounds of normal and putrid crayfish.The results showed that Aeromonas(57%),Macrococcus(7.7%),Vibrio sp.(6.6%),Acinetobacter(5%),Citrobacter(4.9%)and Enterobacter(1.49%)were the main bacterial genus in the refrigerated fresh crayfish(HNA).And Staphylococcus(17.04%),Aeromonas(4.46%),Xanthomonas(4.16%),Streptococcus(4.62%)and Enterococcus(2.77%)were the main bacterial genus in the marinated and refrigerated crayfish(HND).With the spoilage of samples(HNE and HNC),the diversity of bacteria decreased,and the specific spoilage bacteria grew rapidly,mainly Enterococcus,Bacillus,Lactobacillus,Leuconostoc,Weissella.Meanwhile,the volatile compounds in non-spoilage sample(HNA and HND)were mainly alkane compounds,aldehydes compound and esters compounds;and the volatile compounds in spoilage samples were mainly alcohols,acids,benzene compounds,terpenoids,N-containing compounds,S-containing compounds and ethers.This indicated that the contents and types of volatile compounds changed with the sample spoilage and deterioration.Correlation analysis results showed that Enterococcus,Lactobacillus and Bacillus were significantly positively correlated with alcohols,acids,benzene,terpenoids,N-containing compounds,S-containing compounds and ether compounds,while Aeromonas,Megasphaera,Acinetobacter,Citrobacter and Vibrio were significantly positively correlated with alkane compounds and esters compounds,and Leuconostoc were significantly positively correlated with alcohol compounds.These results can provide a theoretical guidance for the storage of cooked flavor crayfish at room temperature.展开更多
The concentration of absorbable particulate matter less than 10 μm termed as PM10 is the most important urban air pollution index for air quality monitoring. This paper presents a space based PM10 monitoring algorith...The concentration of absorbable particulate matter less than 10 μm termed as PM10 is the most important urban air pollution index for air quality monitoring. This paper presents a space based PM10 monitoring algorithm based on QUAC (QUick atmosphere correction) for optical remote sensing data and SVR (support vector regression). PM 10 concentration measurements from nine ground based stations in Hangzhou, China and the MODIS (moderate-resolution imaging spectroradiometer) images were analyzed. Experimental result indicates that the correlation between CD (correction differences) with actual measured data is better than correlation between AOD (aerosol optical depth) with measured data. In addition, the fitting performance of the SVR model established with CD and measured data is better than traditional regression models.展开更多
Outdoor air quality, building materials, HVAC (Heating, Ventilation, Air Conditioning) systems and people activity are important factors in human exposition of polluted indoor air. The degree of signification varies...Outdoor air quality, building materials, HVAC (Heating, Ventilation, Air Conditioning) systems and people activity are important factors in human exposition of polluted indoor air. The degree of signification varies in dependence on pollution character and its sources. Buildings eliminate significantly people exposition of outdoor pollutants, but on the other hand, buildings are significant source of indoor pollution. The contamination of indoor air is largely from the use of gas for heating and cooking appliances. A comprehensive analysis of indoor air pollution by nitrogen oxides shows that the extent of indoor air pollution and consequent exposure varies as a result of many factors mainly the differing dislribution of appliances and their level of use. This study aims to formulate a mathematical model for the production of nitrogen oxides indoors. The physical processes that determine the concentrations of indoor nitrogen oxides as a function of outdoor concentrations, indoor emission rates and building characteristics have been mathematically described. The mathematical model developed has been parameterized for typical Slovak residences. The modeling of the occurrence of indoor nitrogen oxides and verification of the model is presented in this paper.展开更多
The economic development bring serious environmental problems to China, the quality of atmospheric environment has an important bearing on the forecast. Be aimed at the complexity and non-linear of the quality of atmo...The economic development bring serious environmental problems to China, the quality of atmospheric environment has an important bearing on the forecast. Be aimed at the complexity and non-linear of the quality of atmospheric environment, chaos theory has been put forward which takes full advantage of using date information. Based on the reconstruction of time-series phase space of the quality of atmospheric environment with the use of least squares support vector machine theory, the atmospheric environment prediction model was built up, and 25 years of historical data viewed as the raw data of the quality of the environment in Benxi City, giving a practical example, it shows that the results forecasted by the least squares support vector machine and the actual results match the better the forecast accuracy also meet the engineering application.展开更多
The air quality inside vehicle is concerned widely in the world. The pollution inside vehicle is special serious in China. State Environmental Protection Administration of China is formulating the standard of air qual...The air quality inside vehicle is concerned widely in the world. The pollution inside vehicle is special serious in China. State Environmental Protection Administration of China is formulating the standard of air quality inside vehicle. However the measurement relates to many factors. Because of the small space, temperature easy changed, various ventilation modes, being close to pollution source of engine exhaust, there are differences between in-vehicle and indoor measurement. The influence of measuring factors was investigated. Those factors include temperature, preconditioning time, ventilation modes, engine state, and sampling fashion. The measuring mode and relating factors were discussed. The suggestion was offered.展开更多
Suspended particulate matter (SPM) levels in ambient air were monitored at Mandi Gobindgarh, an industrial town of Punjab, India located on the National Highway-1 during November 2001 to March 2002 covering spring a...Suspended particulate matter (SPM) levels in ambient air were monitored at Mandi Gobindgarh, an industrial town of Punjab, India located on the National Highway-1 during November 2001 to March 2002 covering spring and winter seasons to check the variation of SPM and its constituents in the town. The maximum levels of SPM varied between 594 μg/m^3 to 620 μg/m^3 at selected monitoring sites while the minimum levels varied between 209μg/m^3 to 220 μg/m^3. These values were observed always above the National Ambient Air Quality Standards (NAAQS) set by the State regulatory body. Major sources of SPM were identified as the industrial activity and traffic plying on the national highway. Collected SPM samples were further analyzed for the ignitable matter as loss on ignition (LOI) and organic tarry matter (OTM) content. Ignitable component of the SPM constituted about 45% and tarry matter in the ambient air was about 12%. Effects of meteorological parameters like temperature, wind direction and wind speed on SPM levels are discussed.展开更多
Objective:Aroma is the core factor in aromatherapy. Sensory evaluation of aromas differed among three sweet osmanthus (Osmanthus fragrans) cultivar groups. The purpose of this study was to investigate the aroma-act...Objective:Aroma is the core factor in aromatherapy. Sensory evaluation of aromas differed among three sweet osmanthus (Osmanthus fragrans) cultivar groups. The purpose of this study was to investigate the aroma-active compounds responsible for these differences. Methods: Gas chromatography-olfactometry (GC-O) and GC-mass spectrometry (GC-MS) were used to analyze the aroma-active compounds and volatiles of creamy-white (‘Houban Yingui’, HBYG), yellow (‘Liuye Jingui’, LYJG), and orange (‘Gecheng Dangui’, GCDG) cultivars. Results:Seventeen aroma-active compounds were detected among 54 volatiles. trans-β-Ocimene, trans-β-ionone, and linalool, which were major volatiles, were identified as aroma-active, while cis-3-hexenyl butanoate,γ-terpinene, and hexyl butanoate were also aroma-active compounds, although their contents were low. Analysis of the odors was based on the sum of the modified frequency (MF) values of aroma-active compounds in different odor groups. HBYG contained more herb odors, contributed by cis-β-ocimene and trans-β-ocimene, while LYJG had more woody/violet/fruity odors released by trans-β-ionone, α-ionone, and hexyl butanoate. In GCDG, the more floral odors were the result of cis-linalool oxide, trans-linalool oxide, and linalool. Conclusions:Aroma-active compounds were not necessarily only the major volatiles:some volatiles with low content also contributed to aroma. The aroma differences among the three cultivars resulted from variation in the content of different odor groups and in the intensities of aroma-active compounds.展开更多
A theoretical model is developed to predict the upper limit heat transfer between a stack of parallel plates subject to multiphase cooling by air-mist flow.The model predicts the optimal separation distance between th...A theoretical model is developed to predict the upper limit heat transfer between a stack of parallel plates subject to multiphase cooling by air-mist flow.The model predicts the optimal separation distance between the plates based on the development of the boundary layers for small and large separation distances,and for dilute mist conditions.Simulation results show the optimal separation distance to be strongly dependent on the liquid-to-air mass flow rate loading ratio,and reach a limit for a critical loading.For these dilute spray conditions,complete evaporation of the droplets takes place.Simulation results also show the optimal separation distance decreases with the increase in the mist flow rate.The proposed theoretical model shall lead to a better understanding of the design of fins spacing in heat exchangers where multiphase spray cooling is used.展开更多
文摘Based on the analysis of monitoring data on six pollution indexes of SO2, NO2, CO, O3, PM10 and PM2.5 from 53 monitoring points in 7 cities, including Beijing, Tianjin, Shijiazhuang, etc., from April 8 of 2014 to July 23 of 2014, this article adopted Pearson correlation coefficient method to determine the relevance among each pollutant of these cities with the help of SPSS. The results showed that such three leading indexes as SO2, PM10 and PM2.5 had strong correlation in Beijing, Tianjin and main cities of Hebei. Finally, some suggestions and preventive measures for the cooperative governance of air pollution in Beijing-Tianjin-Hebei Region were put forward, hoping this can help them.
基金Project supported by the Postdoctoral Foundation of Changde Cigarette FactoryProject(20060400887) supported by China Postdoctoral Science Foundation
文摘Chromatography-mass spectrometry(GC-MS)was used to analyze the volatile components of cut tobacco samples with the help of heuristic evolving latent projections(HELP).After extracting with simultaneous distillation and extraction method,the volatile components in cut tobacco were detected by GC-MS.Then the obtained original two-dimensional data were resolved into pure mass spectra and chromatograms.The qualitative analysis was performed by similarity searches in the national institute of standards and technology(NIST)mass database with the obtained pure mass spectrum of each component and the quantitative results were obtained by calculating the volume of total two-way response.The accuracy of qualitative and quantitative results were greatly improved by using the two-dimensional comprehensive information of chromatograms and mass spectra.107 of 141 separated constituents in the total ion chromatogram of the volatile components were identified and quantified,accounting for about 88.01% of the total content.The result proves that the developed method is powerful for the analysis of complex cut tobacco samples.
文摘The purpose of the study is to generate traffic air information system) to determine a proper zone of AQMS (air analyzed were carbon monoxide (CO), and nitrogen oxides (NOx) pollution map using mathematical model and GIS (geographic quality monitoring station) in municipality area. The pollutants which can be harmful to people living in the area. The three steps of mapping process were performed under the GIS environment using the existing vehicle emission rates and pollutant dispersion model. First, traffic volume, road network, and the emission rates of road segments varying with types of vehicle were collected from existing data. Second, the pollutant concentrations were calculated by use of CALINE4, a tool with Gaussian dispersion model. The model parameters include emission rate, wind directions and speeds, ambient temperature and observed pollutant concentration, and atmospheric stability during all seasons from the January 1, 2010 to May 31,2011 with regardless the rainy season. This resulted in concentrations at many receptor points along links of the road network. Third, distributions of pollution concentrations were generated by means of the spatial interpolation of those from receptors. The results of pollution raster-based maps are used for determining frequency of violence and combined pollution map. The resulting frequency of violence and intensity concentration will be further integrated to determine a potential area of AQMS. Finally, achieving pollution potential area of AQMS can be located as helpful basic data for efficient traffic and transportation planning.
基金Projects(2007JT3018, 2008JT1013, 2009FJ4056) supported by the Key Project in Hunan Science and Technology Program, ChinaProject(20090161120014) supported by the New Teachers Sustentation Fund in Doctoral Program, Ministry of Education, China
文摘Support vector regression (SVR) method is a novel type of learning machine algorithms, which is seldom applied to the development of urban atmospheric quality models under multiple socio-economic factors. This study presents four SVR models by selecting linear, radial basis, spline, and polynomial functions as kernels, respectively for the prediction of urban dust fall levels. The inputs of the models are identified as industrial coal consumption, population density, traffic flow coefficient, and shopping density coefficient. The training and testing results show that the SVR model with radial basis kernel performs better than the other three both in the training and testing processes. In addition, a number of scenario analyses reveal that the most suitable parameters (insensitive loss function e, the parameter to reduce the influence of error C, and discrete level or average distribution of parameters σ) are 0.001, 0.5, and 2 000, respectively.
基金Supported by the Specialized Research Fund for the Program of Higher Education (No.20050003030) and byTsinghua-Zhongda Postdoctoral Fellowship Program (No.20283600131).
文摘Inter-phase mass transfer is important to the design and performance of airlift loop reactors for either chemical or biochemical applications, and a good measurement technique is crucial for studying mass transfer in multiphase systems. According to the model of macro-scale mass transfer in airlift loop reactors, it was proved that the airlift loop reactor can be regarded as a continuous stirred tank reactor for measuring mass transfer coefficient. The calculated mass transfer coefficient on such a basis is different from the volumetric mass transfer coefficient in the macro-scale model and the difference is discussed. To describe the time delay of the probe response to the change of oxygen concentration in the liquid phase, a model taking into account the time constant of response is es-tablished. Sensitivity analysis shows that this model can be used to measure the volumetric mass transfer coefficient. Applying this model to the measurement of volumetric mass transfer coefficient in the loop reactor, results that co-incide with the turbulence theory in the literate were obtained.
文摘Indoor Environmental Quality (IEQ) deals with providing a healthy and comfortable indoor environment. Most of international sustainability rating systems consider IEQ as a key perspective for developing sustainable buildings. Educational buildings include large number of people which increase the need to provide appropriate IEQ. Accordingly, there is a critical need to frequently assess of IEQ in this type of buildings in order to maintain the satisfactory level of IEQ. This paper aims to develop a framework for assessing and improving the IEQ of educational buildings in Saudi Arabia through measuring the IEQ parameters and integrating these results with Building Information Modeling (BIM). The key IEQ parameters considered in this study include thermal comfort, indoor air quality and visual comfort. These parameters have been measured by comfort-sense system, indoor air quality meter and light meter respectively. The measured data are integrated with BIM model in order to track the IEQ problems, and to develop IEQ history over time. By using the proposed framework, the IEQ can be tracked and improved. The IEQ assessment framework has been implemented on educational building in Saudi Arabia as a case study to validate the process and perform the necessary modifications and improvements.
文摘It is a common issue in the processing industry of crayfish that flavored crayfish stored at room temperature is perishable.In order to establish an effective putrid prediction mechanism,high-throughput sequencing and solid phase microextraction gas chromatography-mass spectrometry(SPME-GCMS)were used to analyse the microbial community structure and volatile flavor compounds of normal and putrid crayfish.The results showed that Aeromonas(57%),Macrococcus(7.7%),Vibrio sp.(6.6%),Acinetobacter(5%),Citrobacter(4.9%)and Enterobacter(1.49%)were the main bacterial genus in the refrigerated fresh crayfish(HNA).And Staphylococcus(17.04%),Aeromonas(4.46%),Xanthomonas(4.16%),Streptococcus(4.62%)and Enterococcus(2.77%)were the main bacterial genus in the marinated and refrigerated crayfish(HND).With the spoilage of samples(HNE and HNC),the diversity of bacteria decreased,and the specific spoilage bacteria grew rapidly,mainly Enterococcus,Bacillus,Lactobacillus,Leuconostoc,Weissella.Meanwhile,the volatile compounds in non-spoilage sample(HNA and HND)were mainly alkane compounds,aldehydes compound and esters compounds;and the volatile compounds in spoilage samples were mainly alcohols,acids,benzene compounds,terpenoids,N-containing compounds,S-containing compounds and ethers.This indicated that the contents and types of volatile compounds changed with the sample spoilage and deterioration.Correlation analysis results showed that Enterococcus,Lactobacillus and Bacillus were significantly positively correlated with alcohols,acids,benzene,terpenoids,N-containing compounds,S-containing compounds and ether compounds,while Aeromonas,Megasphaera,Acinetobacter,Citrobacter and Vibrio were significantly positively correlated with alkane compounds and esters compounds,and Leuconostoc were significantly positively correlated with alcohol compounds.These results can provide a theoretical guidance for the storage of cooked flavor crayfish at room temperature.
文摘The concentration of absorbable particulate matter less than 10 μm termed as PM10 is the most important urban air pollution index for air quality monitoring. This paper presents a space based PM10 monitoring algorithm based on QUAC (QUick atmosphere correction) for optical remote sensing data and SVR (support vector regression). PM 10 concentration measurements from nine ground based stations in Hangzhou, China and the MODIS (moderate-resolution imaging spectroradiometer) images were analyzed. Experimental result indicates that the correlation between CD (correction differences) with actual measured data is better than correlation between AOD (aerosol optical depth) with measured data. In addition, the fitting performance of the SVR model established with CD and measured data is better than traditional regression models.
文摘Outdoor air quality, building materials, HVAC (Heating, Ventilation, Air Conditioning) systems and people activity are important factors in human exposition of polluted indoor air. The degree of signification varies in dependence on pollution character and its sources. Buildings eliminate significantly people exposition of outdoor pollutants, but on the other hand, buildings are significant source of indoor pollution. The contamination of indoor air is largely from the use of gas for heating and cooking appliances. A comprehensive analysis of indoor air pollution by nitrogen oxides shows that the extent of indoor air pollution and consequent exposure varies as a result of many factors mainly the differing dislribution of appliances and their level of use. This study aims to formulate a mathematical model for the production of nitrogen oxides indoors. The physical processes that determine the concentrations of indoor nitrogen oxides as a function of outdoor concentrations, indoor emission rates and building characteristics have been mathematically described. The mathematical model developed has been parameterized for typical Slovak residences. The modeling of the occurrence of indoor nitrogen oxides and verification of the model is presented in this paper.
文摘The economic development bring serious environmental problems to China, the quality of atmospheric environment has an important bearing on the forecast. Be aimed at the complexity and non-linear of the quality of atmospheric environment, chaos theory has been put forward which takes full advantage of using date information. Based on the reconstruction of time-series phase space of the quality of atmospheric environment with the use of least squares support vector machine theory, the atmospheric environment prediction model was built up, and 25 years of historical data viewed as the raw data of the quality of the environment in Benxi City, giving a practical example, it shows that the results forecasted by the least squares support vector machine and the actual results match the better the forecast accuracy also meet the engineering application.
文摘The air quality inside vehicle is concerned widely in the world. The pollution inside vehicle is special serious in China. State Environmental Protection Administration of China is formulating the standard of air quality inside vehicle. However the measurement relates to many factors. Because of the small space, temperature easy changed, various ventilation modes, being close to pollution source of engine exhaust, there are differences between in-vehicle and indoor measurement. The influence of measuring factors was investigated. Those factors include temperature, preconditioning time, ventilation modes, engine state, and sampling fashion. The measuring mode and relating factors were discussed. The suggestion was offered.
文摘Suspended particulate matter (SPM) levels in ambient air were monitored at Mandi Gobindgarh, an industrial town of Punjab, India located on the National Highway-1 during November 2001 to March 2002 covering spring and winter seasons to check the variation of SPM and its constituents in the town. The maximum levels of SPM varied between 594 μg/m^3 to 620 μg/m^3 at selected monitoring sites while the minimum levels varied between 209μg/m^3 to 220 μg/m^3. These values were observed always above the National Ambient Air Quality Standards (NAAQS) set by the State regulatory body. Major sources of SPM were identified as the industrial activity and traffic plying on the national highway. Collected SPM samples were further analyzed for the ignitable matter as loss on ignition (LOI) and organic tarry matter (OTM) content. Ignitable component of the SPM constituted about 45% and tarry matter in the ambient air was about 12%. Effects of meteorological parameters like temperature, wind direction and wind speed on SPM levels are discussed.
基金Project supported by the PhD Program Foundation of the Ministry of Education of China(No.20130146110022)the National Natural Science Foundation of China(No.31070623)
文摘Objective:Aroma is the core factor in aromatherapy. Sensory evaluation of aromas differed among three sweet osmanthus (Osmanthus fragrans) cultivar groups. The purpose of this study was to investigate the aroma-active compounds responsible for these differences. Methods: Gas chromatography-olfactometry (GC-O) and GC-mass spectrometry (GC-MS) were used to analyze the aroma-active compounds and volatiles of creamy-white (‘Houban Yingui’, HBYG), yellow (‘Liuye Jingui’, LYJG), and orange (‘Gecheng Dangui’, GCDG) cultivars. Results:Seventeen aroma-active compounds were detected among 54 volatiles. trans-β-Ocimene, trans-β-ionone, and linalool, which were major volatiles, were identified as aroma-active, while cis-3-hexenyl butanoate,γ-terpinene, and hexyl butanoate were also aroma-active compounds, although their contents were low. Analysis of the odors was based on the sum of the modified frequency (MF) values of aroma-active compounds in different odor groups. HBYG contained more herb odors, contributed by cis-β-ocimene and trans-β-ocimene, while LYJG had more woody/violet/fruity odors released by trans-β-ionone, α-ionone, and hexyl butanoate. In GCDG, the more floral odors were the result of cis-linalool oxide, trans-linalool oxide, and linalool. Conclusions:Aroma-active compounds were not necessarily only the major volatiles:some volatiles with low content also contributed to aroma. The aroma differences among the three cultivars resulted from variation in the content of different odor groups and in the intensities of aroma-active compounds.
文摘A theoretical model is developed to predict the upper limit heat transfer between a stack of parallel plates subject to multiphase cooling by air-mist flow.The model predicts the optimal separation distance between the plates based on the development of the boundary layers for small and large separation distances,and for dilute mist conditions.Simulation results show the optimal separation distance to be strongly dependent on the liquid-to-air mass flow rate loading ratio,and reach a limit for a critical loading.For these dilute spray conditions,complete evaporation of the droplets takes place.Simulation results also show the optimal separation distance decreases with the increase in the mist flow rate.The proposed theoretical model shall lead to a better understanding of the design of fins spacing in heat exchangers where multiphase spray cooling is used.