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Monte Carlo method for evaluation of surface emission rate measurement uncertainty
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作者 Yuan-Qiao Li Min Lin +4 位作者 Li-Jun Xu Rui Luo Yu-He Zhang Qian-Xi Ni Yun-Tao Liu 《Nuclear Science and Techniques》 SCIE EI CAS CSCD 2024年第7期126-136,共11页
The aim of this study is to evaluate the uncertainty of 2πα and 2πβ surface emission rates using the windowless multiwire proportional counter method.This study used the Monte Carlo method (MCM) to validate the co... The aim of this study is to evaluate the uncertainty of 2πα and 2πβ surface emission rates using the windowless multiwire proportional counter method.This study used the Monte Carlo method (MCM) to validate the conventional Guide to the Expression of Uncertainty in Measurement (GUM) method.A dead time measurement model for the two-source method was established based on the characteristics of a single-channel measurement system,and the voltage threshold correction factor measurement function was indirectly obtained by fitting the threshold correction curve.The uncertainty in the surface emission rate was calculated using the GUM method and the law of propagation of uncertainty.The MCM provided clear definitions for each input quantity and its uncertainty distribution,and the simulation training was realized with a complete and complex mathematical model.The results of the surface emission rate uncertainty evaluation for four radioactive plane sources using both methods showed the uncertainty’s consistency E_(n)<0.070 for the comparison of each source,and the uncertainty results of the GUM were all lower than those of the MCM.However,the MCM has a more objective evaluation process and can serve as a validation tool for GUM results. 展开更多
关键词 Surface emission rate Monte Carlo method METROLOGY Probability distribution function Dead time Low-energy loss correction Least-squares method
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Sensitivity analysis of project level MOVES running emission rates for light and heavy duty vehicles 被引量:8
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作者 Zhuo Yao Heng Wei +2 位作者 Harikishan Peragu Hao Liu Zhixia Li 《Journal of Traffic and Transportation Engineering(English Edition)》 2014年第2期81-96,共16页
In order to understand how the uncertainties in the output can be apportioned to different sources of uncertainties in its inputs, it is critical to investigate the sensitivity of MOVES model. The MOVES model sensitiv... In order to understand how the uncertainties in the output can be apportioned to different sources of uncertainties in its inputs, it is critical to investigate the sensitivity of MOVES model. The MOVES model sensitivity for regional level has been well studied. However, the uncertainty analysis for project level running emissions has not been well understood. In this research, the MOVES model project level sensitivity tests on running emissions were conducted thru the analysis of vehicle specific power (VSP), scaled tractive power (STP), and MOVES emission rates versus speed curves. This study tested the speed, acceleration, and grade-three most critical variables for vehicle specific power for light duty vehicles and scaled tractive power for heavy duty vehicles. For the testing of STP, four regulatory classes of heavy duty vehicles including light heavy duty (LHD), medium heavy duty (MHD), heavy heavy duty (HHD) and bus were selected. MOVES project running emission rates were also tested for CO, PM2.5, NOx, and VOC versus the operating speeds. A Latin Hypercube (LH) sampling based on method for estimation of the "Sobal" sensitivity indices shows that the speed is the most critical variable among the three inputs for both VSP and STP. Acceleration and grades show lower response to the main effects and sensitivity indices. MOVES emission rates versus speeds curves for light duty vehicles show that highest emission occurs at lower speed range. No significant differences on emission rates among the regulatory classes of heavy duty vehicles are identified. 展开更多
关键词 MOVES model sensitivity analysis project level emission rates
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Artificial neural network algorithm for pulse shape discrimination in 2πα and 2πβ particle surface emission rate measurements
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作者 Yuan-Qiao Li Bao-Ji Zhu +4 位作者 Yang Lv Heng Zhu Min Lin Ke-Sheng Chen Li-Jun Xu 《Nuclear Science and Techniques》 SCIE EI CAS CSCD 2023年第10期91-102,共12页
To enhance the accuracy of 2πα and 2πβ particle surface emission rate measurements and address the identification issues of nuclides in conventional methods, this study introduces two artificial neural network(ANN... To enhance the accuracy of 2πα and 2πβ particle surface emission rate measurements and address the identification issues of nuclides in conventional methods, this study introduces two artificial neural network(ANN) algorithms: back-propagation(BP) and genetic algorithm-based back-propagation(GA-BP). These algorithms classify pulse signals from distinct α and β particles. Their discrimination efficacy is assessed by simulating standard pulse signals and those produced by contaminated sources, mixing α and β particles within the detector. This study initially showcases energy spectrum measurement outcomes, subsequently tests the ANNs on the measurement and validation datasets, and contrasts the pulse shape discrimination efficacy of both algorithms. Experimental findings reveal that the proportional counter's energy resolution is not ideal, thus rendering energy analysis insufficient for distinguishing between 2πα and 2πβ particles. The BP neural network realizes approximately 99% accuracy for 2πα particles and approximately 95% for 2πβ particles, thus surpassing the GA-BP's performance. Additionally, the results suggest enhancing β particle discrimination accuracy by increasing the digital acquisition card's threshold lower limit. This study offers an advanced solution for the 2πα and 2πβ surface emission rate measurement method, presenting superior adaptability and scalability over conventional techniques. 展开更多
关键词 Pulse shape discrimination Artificial neural networks Alpha and beta sources Multi-wire proportional counter Surface emission rate
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Wind tunnel experiments on dust emissions from different landform types 被引量:6
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作者 WU Wei YAN Ping +3 位作者 WANG Yong DONG Miao MENG Xiaonan JI Xinran 《Journal of Arid Land》 SCIE CSCD 2018年第4期548-560,共13页
The measurement and assessment of dust emissions from different landforms are important to understand the atmospheric loading of PM10 (particulate matter ≤10 μm aerodynamic diameter) and to assess natural sources ... The measurement and assessment of dust emissions from different landforms are important to understand the atmospheric loading of PM10 (particulate matter ≤10 μm aerodynamic diameter) and to assess natural sources of dust; however, the methodology and technique for determining the dust still present significant research challenges. In the past, specialized field observation and field wind tunnel studies have been used to understand the dust emission. A series of wind tunnel tests were carried out to identify natural sources of dust and measure the magnitudes of dust emissions from different landforms. The method used in this study allowed the measurement of the PM10 emission rate using a laboratory based environmental boundary layer wind tunnel. Results indicated that PM10 emissions demonstrated strong temporal variation and were primarily driven by aerodynamic entrainment. Sand dunes, playa, and alluvial fans had the largest dust emission rates (0.8-5.4 mg/(me.s)) while sandy gravel, Gobi desert and abandoned lands had the lowest emission rates (0.003-0.126 mg/(m2.s)). Dust emissions were heavily dependent on the surface conditions, especially the availability of loose surface dust. High dust emissions were a result of the availability of dust- particle materials for entrainment while low dust emissions were a result of surface crusts and gravel cover. Soil surface property (surface crusts and gravel cover) plays an important role in controlling the availability of dust-sized particles for entrainment. The dust emission rate depended not only on the surface conditions but also on the friction velocity. The emission rate of PM10 varies as a power function of the friction velocity. Although dynamic abrasion processes have a strong influence on the amount of dust entrainment, aerodynamic entrainment may provide an important mechanism for dust emissions. Large volumes of dust entrained by aerodynamic entrainment cannot only occur at low shear velocity without saltation, but may dominate the entrainment process in many arid and semi-arid environments. So it may also be responsible for large magnitude dust storms. Playa and alluvial fan landforms, prior to developing a surface crust, may be the main sources of dust storms in Qinghai Province. 展开更多
关键词 emission rates PMIO fugitive dust LANDFORMS wind tunnel dust dynamics
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The Turbulent Schmidt Number for Transient Contaminant Dispersion in a Large Ventilated Room Using a Realizable k-εModel
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作者 Fei Wang Qinpeng Meng +3 位作者 Jinchi Zhao Xin Wang Yuhong Liu Qianru Zhang 《Fluid Dynamics & Materials Processing》 EI 2024年第4期829-846,共18页
Buildings with large open spaces in which chemicals are handled are often exposed to the risk of explosions.Computational fluid dynamics is a useful and convenient way to investigate contaminant dispersion in such lar... Buildings with large open spaces in which chemicals are handled are often exposed to the risk of explosions.Computational fluid dynamics is a useful and convenient way to investigate contaminant dispersion in such large spaces.The turbulent Schmidt number(Sc_(t))concept has typically been used in this regard,and most studies have adopted a default value.We studied the concentration distribution for sulfur hexafluoride(SF_(6))assuming different emission rates and considering the effect of Sc_(t).Then we examined the same problem for a light gas by assuming hydrogen gas(H_(2))as the contaminant.When SF_(6) was considered as the contaminant gas,a variation in the emission rate completely changed the concentration distribution.When the emission rate was low,the gravitational effect did not take place.For both low and high emission rates,an increase in S_(ct) accelerated the transport rate of SF_(6).In contrast,for H_(2) as the contaminant gas,a larger S_(ct) could induce a decrease in the H_(2) transport rate. 展开更多
关键词 Large space CFD turbulent Schmidt number contaminant dispersion emission rate
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Effect of water stress on N_2O emission rate of 5 tree species
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作者 王淼 李秋荣 +1 位作者 肖冬梅 王长科 《Journal of Forestry Research》 SCIE CAS CSCD 2004年第1期19-23,J001,共6页
The N2O emission rates, photosynthesis, respiration and stomatal conductance of the dominant tree species from broadleaf/Korean pine forest in Changbai Mountain were measured by simulated water stress with the closed ... The N2O emission rates, photosynthesis, respiration and stomatal conductance of the dominant tree species from broadleaf/Korean pine forest in Changbai Mountain were measured by simulated water stress with the closed bag-gas chromatography. A total of five species seedlings were involved in this study, i.e.,Pinus koraiensis Sieb. et Zucc,Fraxinus mandshurica Rupr,Juglans mandshurica Maxim,Tilia amurensis Rupr, andQuercus mongolica Fisch. ex Turcz.. The results showed that the stomatal conductance, net photosynthetic rate and N2O emission of leaves were significantly reduced under the water stress. The stoma in the leaves of trees is the main pathway of N2O emission. N2O emission in the trees mainly occurred during daytime. N2O emission rates were different in various tree specie seedlings at the same water status. In the same tree species, N2O emission rates decreased as the reduction of soil water contents. At different soil water contents (MW, LW) the N2O emission rates ofPinus koraiensis decreased by 34.43% and 100.6% of those in normal water condition, respectively. In broadleaf arbor decreased by 31.93% and 86.35%, respectively. Under different water stresses N2O emission rates in five tree species such asPinus koraiensis, Fraxinus mandshurica, Juglans mandshurica, Tilia amurensis, andQuercus mongolica were 38.22, 14.44, 33.02, 16.48 and 32.33 ngN2O·g?1DW·h?1, respectively. Keywords Trees - N2O emission rate - Soil water stress - broadleaf/Korean pine forest - Changbai Mountain CLC number S718.55 Document code A Foundation item: This project was supported by the National Natural Science Foundation of China (No. 30271068), the grant of the Knowledge Innovation Program of Chinese Academy of Sciences (KZ-CX-SW-01-01B-10), and the Special Funds for Major State Basic Research Program of China (No. G1999043407)Biography: Wang Miao (1964-), male, associate professor in Institute of Applied Ecology, Chinese Academy of Science, Shenyang 110016, P. R. China.Responsible editor: Song Funan 展开更多
关键词 Trees N2O emission rate Soil water stress broadleaf/Korean pine forest Changbai Mountain
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Determination of Particulate Matter Emissions from Cattle Feedlots Using Wind-Trax and the Flux-Gradient Technique 被引量:1
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作者 Henry F. Bonifacio Ronaldo G. Maghirang +3 位作者 Steven L. Trabue Laura L. McConnell John H. Prueger Edna R. Bonifacio 《Journal of Environmental Protection》 2016年第2期176-189,共14页
Large commercial cattle feedlots are significant sources of particulate matter (PM) emissions. This research compared WindTrax and the flux-gradient technique in estimating emissions of PM with aerodynamic diameter &l... Large commercial cattle feedlots are significant sources of particulate matter (PM) emissions. This research compared WindTrax and the flux-gradient technique in estimating emissions of PM with aerodynamic diameter < 10 μm (PM<sub>10</sub>) from cattle feedlots. Meteorological conditions were measured and PM<sub>10</sub> concentrations were profiled vertically (i.e., 2.0 to 7.62 m) at a large commercial beef cattle feedlot in Kansas from May through September 2011. Results show that between the two methods evaluated, WindTrax was least sensitive to changes in heights and number of heights used in the emission estimation, with calculated PM<sub>10</sub> emission rates varying by up to 18% only. On the other hand, PM<sub>10</sub> emission rates produced by the flux-gradient technique varied by almost 56% when changing either heights and/or number of heights in emission calculation. Both methods were sensitive to height settings, with their respective PM<sub>10</sub> emission rates higher when the lowest height setting (2.0 m) was included. Calculating PM<sub>10</sub> emission rates with the 7.62-m height led to lower estimates for the flux-gradient technique but no significant change in estimates was observed for WindTrax. As demonstrated in this study, for the flux-gradient technique, settings for the lowest and highest heights were the most critical in emission estimation;exclusion of other heights in between showed only to 2% to 6% change in calculated PM<sub>10</sub> emission rates. In general, the higher PM<sub>10</sub> emission rates were obtained with the flux-gradient technique. However, eliminating the lowest height (2.0 m) in the calculation and, at the same time, using a specific set of formulations for the flux-gradient technique made its calculated PM<sub>10</sub> emission rates slightly lower (but not significantly different) than those from WindTrax. 展开更多
关键词 PM10 emission rates Cattle Feedlots emission Rate Estimation WindTrax Flux-Gradient Technique
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Effect of spatially nonlocal versus local optical response of a gold nanorod on modification of the spontaneous emission 被引量:5
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作者 Sha-Sha Wen Meng Tian +8 位作者 Hong Yang Su-Jun Xie Xiao-Yun Wang Yun Li Jie Liu Jin-Zhang Peng Ke Deng He-Ping Zhao Yong-Gang Huang 《Chinese Physics B》 SCIE EI CAS CSCD 2021年第2期520-528,共9页
The spontaneous emission rate of a two-level quantum emitter(QE)near a gold nanorod is numerically investigated.Three different optical response models for the free-electron gas are adopted,including the classical Dru... The spontaneous emission rate of a two-level quantum emitter(QE)near a gold nanorod is numerically investigated.Three different optical response models for the free-electron gas are adopted,including the classical Drude local response approximation,the nonlocal hydrodynamic model,and the generalized nonlocal optical response model.Nonlocal optical response leads to a blueshift and a reduction in the enhancement of the spontaneous emission rate.Within all the three models,the resonance frequency is largely determined by the aspect ratio(the ratio of the nanorod length to the radius)and increases sharply with decreasing aspect ratio.For nanorod with a fixed length,it is found that the larger the radius is,the higher the resonance frequency is,and the smaller the enhancement is.However,if the length of the nanorod increases,the peak frequency falls sharply,while the spontaneous emission enhancement grows rapidly.For nanorod with a fixed aspect ratio,the peak frequency decreases slowly with increasing nanorod size.Larger nanorod shows smaller nonlocal effect.At a certain frequency,there is an optimal size to maximize the enhancement of the spontaneous emission rate.Higher order modes are more affected by the nonlocal smearing of the induced charges,leading to larger blueshift and greater reduction in the enhancement.These results should be significant for investigating the spontaneous emission rate of a QE around a gold nanorod. 展开更多
关键词 spatially nonlocal response HYDRODYNAMICS spontaneous emission rate gold nanorod
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Acoustic emission characteristics and stress release rate of coal samples in different dynamic destruction time 被引量:3
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作者 Xiao Fukun Liu Gang +3 位作者 Zhang Ze Shen Zhiliang Zhang Fengrui Wang Yifei 《International Journal of Mining Science and Technology》 SCIE EI CSCD 2016年第6期981-988,共8页
Considering the importance of the prediction of rock burst disasters, and in order to grasp the law of acoustic emission(AE) of coal samples in different dynamic destruction time, the SH-II AE monitoring system was ad... Considering the importance of the prediction of rock burst disasters, and in order to grasp the law of acoustic emission(AE) of coal samples in different dynamic destruction time, the SH-II AE monitoring system was adopted to monitor the failure process of coal samples. The study of the change rule of the AE numbers, energy, ‘b' value and spectrum in the micro crack propagation process of the coal samples shows that as dynamic damage time went by, AE presented high-energy counts and the accumulated counts increased during the compression phase. The AE energy and cumulative counts increased during the elastic stage. The AE blank area increased gradually and the blank lines were more and more obvious in the molding stage. The AE counts and energy showed a trend of decrease in the residual damage phase.AE ‘b' values gradually became sparse, and the large scale cracks percentage compared with micro cracks decreased and the degree of damage decreased. The AE frequency spectrum peak went from the residual damage phase to the molding phase, and finally it was nearly stable, besides the bandwidth of the main frequency is gradually narrowed. Also, the frequency peak changed from single peak frequency to bi-peak frequency and to the single peak frequency. Uniaxial compressive strength is more sensitive than the elastic modulus to dynamic damage time. 展开更多
关键词 Dynamic destruction time Acoustic emission Outburst-proneness Stress release rate
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Effective Solution Algorithm for Tomographic Inversion of Volume Emission Rate from Satellite-based Limb Measurement
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作者 WANG Zijun CHEN Shengbo 《Chinese Geographical Science》 SCIE CSCD 2011年第5期554-562,共9页
The volume emission rate (VER) of airglow can be used to investigate atmospheric processes. Satellite-based limb measurement of atmosphere is able to obtain the VER profile of airglow with high vertical resolution. Ho... The volume emission rate (VER) of airglow can be used to investigate atmospheric processes. Satellite-based limb measurement of atmosphere is able to obtain the VER profile of airglow with high vertical resolution. However, the traditional one-dimensional retrieval techniques for VER inversion fail to retrieve horizontal structure of VER profile. Thus, the tomographic technique based on the maximum probability is applied to retrieving two-dimensional VER profile of airglow from infrared limb measurement. This technique could process the observed data with low signal-to-noise ratio caused by the observation angle of less than 180° due to the solid nature of the Earth. For saving the processing time and improving the computing speed of VER inversion, serial tables for storing the large sparse matrix for radiance simulation and a large dataset during iterative estimate of VER are presented. The index and weighting factor of line of sight (LOS) through each grid are saved in initial estimate to avoid being computed repeatedly. Furthermore, the product of observed radiance and corresponding weighting factor obtained in initial iteration is stored as weighted observed radiance for the iterative calculation subsequently. Based on the improved algorithm, the VER of airglow is inversed through the tomographic technique. The full width of half maximum (FWHM) of error is 1.78% and the offset of the peak percentage error is 0.22% after 40 iterations for final VER. Comparison of assumed and retrieved VER profiles suggests that VER can be retrieved with a bias of 15% between 10 km and 90 km above the LayerMin (6384 km from the Earth center), and with a bias of 8% for altitude from 30 km to 60 km with vertical resolution of 1 km after 40 iterations. After improvements, the computation speed of VER inversion for once can be improved by 29.6 times for 700 images of 1/3 orbit, and accordingly, the processing time will be reduced from 3 hours and 11 minutes to only 6 minutes. In conclusion, the improvements to tomographic inversion of VER of airglow proposed in this paper are effective and significant. 展开更多
关键词 volume emission rate tomographic technique limb measurement RADIANCE AIRGLOW
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Extracting Oscillation Frequencies in Spontaneous Emission Rate of an Atom Between Two Mirrors
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作者 ZHAO Hai-Jun DU Meng-Li 《Communications in Theoretical Physics》 SCIE CAS CSCD 2007年第1期127-130,共4页
For an atom in a medium with refractive index n sandwiched between two parallel mirrors, we derive an analytical formula for the spontaneous emission rate based on Fermi's golden rule. The oscillations are not transp... For an atom in a medium with refractive index n sandwiched between two parallel mirrors, we derive an analytical formula for the spontaneous emission rate based on Fermi's golden rule. The oscillations are not transparent in this formula. By performing Fourier transform on scaling variable measuring system size while holding system configuration fixed, we extracted the frequencies of many oscillations in this system. We show that these oscillations correspond to emitted photon closed-orblts going away from and returning to the emitting atom. 展开更多
关键词 spontaneous emission rate fourier transform closed-orbits
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Modification of spontaneous emission rate of micrometer-sized light sources using hollow-core photonic crystal fibers
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作者 卢娇华 蒙自明 +6 位作者 刘海英 冯天华 戴峭峰 吴立军 郭旗 胡巍 兰胜 《Chinese Physics B》 SCIE EI CAS CSCD 2009年第10期4333-4338,共6页
We investigate numerically and experimentally the modification of the spontaneous emission rate for micrometersized light sources embedded in a hollow-core photonic crystal fiber (HCPCF). The diameter of the light s... We investigate numerically and experimentally the modification of the spontaneous emission rate for micrometersized light sources embedded in a hollow-core photonic crystal fiber (HCPCF). The diameter of the light source is deliberately chosen such that they could be easily introduced into the central hole of the hollow-core photonic crystal fiber by capillary force. The photoluminescence from the microparticles is measured by using an inverted microscope in combination with a spectrometer. The modification of the spontaneous emission rate is observed in a wavelength region where there is no band gap. The experimental observations are consistent with the simulation results obtained by the plane wave expansion and finite-difference time-domain techniques. 展开更多
关键词 hollow-core photonic crystal fiber spontaneous emission rate local density of states
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Temperature Dependence of Thermal Emission Rate in Cr: GaAs
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作者 LIU Jinsong LIANG Changhong(Xidian University, Xi’an 710071, CHN ) 《Semiconductor Photonics and Technology》 CAS 1996年第3期180-183,共4页
The new method of measuring the ratio of thermal emission rate to the photoexcitation constant is presented. The temperature dependence of the ratio for Cr:GaAs is calculated by using the previously published data of ... The new method of measuring the ratio of thermal emission rate to the photoexcitation constant is presented. The temperature dependence of the ratio for Cr:GaAs is calculated by using the previously published data of two-wave mixing. Results show that the calculating data and previous phenomenological theoretic ones coincide with each other very well. 展开更多
关键词 Photorefractive Effect Thermal emission Rate Two-wave Mixing
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The relationship between oxidative degradation and ammonia emission of carbon capture amines based on their chemical structures
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作者 Pailin Muchan Teeradet Supap +1 位作者 Jessica Narku-Tetteh Supranee Lisawadi 《Clean Energy》 EI CSCD 2024年第1期134-152,共19页
This work investigates the effect of chemical structural positioning of different functional groups in 29 amines covering primary,secondary and tertiary alkanolamines as well as multi-alkylamines and cyclic amines on ... This work investigates the effect of chemical structural positioning of different functional groups in 29 amines covering primary,secondary and tertiary alkanolamines as well as multi-alkylamines and cyclic amines on both amine degradation and ammonia(NH_(3))emissions during post-combustion amine-based carbon dioxide capture.The results helped to elucidate possible relation-ships between degradation and emissions as related to the chemical structure of the amine.The results showed that longer alkyl chain lengths in multi-alkylamines caused a more drastic decrease in both degradation and NH_(3) emissions followed by secondary alkanolamines.The decrease in those activities for primary and tertiary alkanolamines as well as cyclic amines was low and more so for NH_(3) emissions.In contrast,the increase in hydroxyl groups in secondary alkanolamines caused a drastic increase in degrad-ation and NH_(3) emissions.On the other hand,having more hydroxyl groups in sterically hindered primary and tertiary alkanolamines caused a more drastic decrease in degradation and a smaller decrease in NH_(3) emissions due to the steric hindrance within their structure.An increase in the number of amino groups in an amine caused an increase in both degradation and NH_(3) emission rates because these provided the reactive sites for the formation of free radicals.This effect was not as large in alkyl-cyclic amines as in multi-alkylamines due to the ability of the former to resist oxidative degradation.Furthermore,branched alkyl groups between amino and hydroxyl groups more drastically increased both the degradation and NH_(3) emission activities than branched alkyl groups located at the nitrogen atom. 展开更多
关键词 amine degradation rate ammonia emission rate carbon capture amine structure oxidative degradation AMINES
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The airborne contagiousness of respiratory viruses:A comparative analysis and implications for mitigation 被引量:2
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作者 Alex Mikszewski Luca Stabile +1 位作者 Giorgio Buonanno Lidia Morawska 《Geoscience Frontiers》 SCIE CAS CSCD 2022年第6期257-264,共8页
The infectious emission rate is a fundamental input parameter for airborne transmission risk assessment,but data are limited due to reliance on estimates from chance superspreading events.This study assesses the stren... The infectious emission rate is a fundamental input parameter for airborne transmission risk assessment,but data are limited due to reliance on estimates from chance superspreading events.This study assesses the strength of a predictive estimation approach developed by the authors for SARS-CoV-2 and uses novel estimates to compare the contagiousness of respiratory pathogens.We applied the approach to SARS-CoV-1,SARS-CoV-2,MERS,measles virus,adenovirus,rhinovirus,coxsackievirus,seasonal influenza virus and Mycobacterium tuberculosis(TB)and compared quanta emission rate(ER)estimates to literature values.We calculated infection risk in a prototypical classroom and barracks to assess the relative ability of ventilation to mitigate airborne transmission.Our median standing and speaking ERestimate for SARS-CoV-2(2.7 quanta h)is similar to active,untreated TB(3.1 quanta h),higher than seasonal influenza(0.17 quanta h-1),and lower than measles virus(15 quanta h).We calculated event reproduction numbers above 1 for SARS-CoV-2,measles virus,and untreated TB in both the classroom and barracks for an activity level of standing and speaking at low,medium and high ventilation rates of 2.3,6.6 and 14 L per second per person(L sp),respectively.Our predictive ERestimates are consistent with the range of values reported over decades of research.In congregate settings,current ventilation standards are unlikely to control the spread of viruses with upper quartile ERqvalues above 10 quanta h,such as SARS-CoV-2,indicating the need for additional control measures. 展开更多
关键词 SARS-CoV-2(COVID-19)airborne transmission Quanta emission rate Ventilation MEASLES INFLUENZA
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Quantum Aspects of the Joule-Lenz Law 被引量:3
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作者 Stanisław Olszewski 《Journal of Modern Physics》 2016年第1期162-174,共13页
Quantum aspects of the Joule-Lenz law for the dissipation energy have been studied. In the first step, in an analysis of the energy-time principle of uncertainty, this gives a lower limit of the time interval and an u... Quantum aspects of the Joule-Lenz law for the dissipation energy have been studied. In the first step, in an analysis of the energy-time principle of uncertainty, this gives a lower limit of the time interval and an upper limit of the energy interval which can be admitted in a quantum transition process. Moreover, for the low energy excitations, the transition time between the levels is found to be close to the oscillation time periods characteristic for these levels. A reference obtained among the transition time Δt, transition energy ΔE and the Planck constant h indicates that Δt should approach approximately the time period of the electromagnetic wave produced in course of the transition. 展开更多
关键词 Joule-Lenz Law Quanta of Energy Uncertainty Principle for Energy and Time Energy emission Rate
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Quantum Corrections to the Radiation of Schwarzschild-anti-de Sitter Black Hole with Topological Defect
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作者 HAN Yi-Wen YANG Shu-Zheng 《Communications in Theoretical Physics》 SCIE CAS CSCD 2007年第6期1145-1147,共3页
We extend Zhang and Zhao's recent work to the Schwarzschild-anti-de Sitter black hole with topological defect, whose Arnowitt-Deser-Misner (ADM) mass is no longer identical to its mass parameter. The behavior of t... We extend Zhang and Zhao's recent work to the Schwarzschild-anti-de Sitter black hole with topological defect, whose Arnowitt-Deser-Misner (ADM) mass is no longer identical to its mass parameter. The behavior of the tunneling massive particle is investigated and the emission rate is calculated. The result satisfies an underlying unitary theory and takes the same functional form as that of the mass-less particle. 展开更多
关键词 black hole ADM mass emission rate quantum theory Hamilton-Jacobi method
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Separating emitted dust from the total suspension in airflow based on the characteristics of PM10 vertical concentration profiles on a Gobi surface in northwestern China
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作者 ZHANG Chunlai WANG Xuesong +2 位作者 CEN Songbo ZHENG Zhongquan Charlie WANG Zhenting 《Journal of Arid Land》 SCIE CSCD 2022年第6期589-603,共15页
During aeolian processes,the two most critical factors related to dust emissions are soil particle and aggregate saltation,which greatly affect the vertical profiles of near-surface dust concentrations.In this study,w... During aeolian processes,the two most critical factors related to dust emissions are soil particle and aggregate saltation,which greatly affect the vertical profiles of near-surface dust concentrations.In this study,we measured PM10 concentrations at four different heights(0.10,0.50,1.00 and 2.00 m)with and without continuous and simultaneous aeolian saltation processes on a Gobi surface in northwestern China from 31 March to 10 April,2017.We found that the vertical concentration profiles of suspended PM10 matched the log-law model well when there was no aeolian saltation.For the erosion process with saltation,we divided the vertical concentration profiles of PM10 into the saltation-affected layer and the airflow-transport layer according to two different dust sources(i.e.,locally emitted PM10 and upwind transported PM10).The transition height between the saltation-affected layer and the airflow-transport layer was not fixed and varied with saltation intensity.From this new perspective,we calculated the airflow-transport layer and the dust emission rate at different times during a wind erosion event occurred on 5 April 2017.We found that dust emissions during wind erosion are primarily controlled by saltation intensity,contributing little to PM10 concentrations above the ground surface compared to PM10 concentrations transported from upwind directions.As erosion progresses,the surface supply of erodible grains is the most crucial factor for saltation intensity.When there was a sufficient amount of erodible grains,there was a significant correlation among the friction velocity,saltation intensity and dust emission rate.However,when supply is limited by factors such as surface renewal or an increase in soil moisture,the friction velocity will not necessarily correlate with the other two factors.Therefore,for the Gobi surface,compared to limiting dust emissions from upwind directions,restricting the transport of suspended dust in its path is by far a more efficient and realistic option for small areas that are often exposed to dust storms.This study provides some theoretical basis for correctly estimating PM10 concentrations in the Gobi areas. 展开更多
关键词 PM10 vertical concentration profiles dust emission rate saltation intensity suspensions Gobi surface
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Quantum and Classical Approach Applied to the Motion of a Celestial Body in the Solar System
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作者 Stanisław Olszewski 《Journal of Modern Physics》 2016年第14期1901-1908,共8页
According to the classical mechanics the energy of a celestial body circulating in the solar system is a constant term. This energy is defined by the masses product of the larger and smaller body entering into a mutua... According to the classical mechanics the energy of a celestial body circulating in the solar system is a constant term. This energy is defined by the masses product of the larger and smaller body entering into a mutual attraction as well as the size of the major semiaxis characteristic for the corresponding Kepler orbit. A special situation concerns the planet interaction with the Sun because of a systematic decrease of the Sun mass due to the luminosity effect. The aim of the paper is to point out that even in the case of perfectly constant interacting masses the energy of the moving body should decrease when a quantum treatment of the body motion is considered. The rate of the energy decrease is extremely small, nevertheless it gives a shortening of the distance between the interacting bodies leading to a final effect of a touch of the larger body and a smaller one. 展开更多
关键词 Solar System Classical Mechanics and Quantum Theory emission Rate of Energy by a Moving Planet The Earth Planet Taken as an Example
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Chemical and olfactive impacts of organic matters on odor emission patterns from the simulated construction and demolition waste landfills 被引量:1
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作者 Kunyu Jiang Zhaowen Cheng +4 位作者 Ziyang Lou Luochun Wang Hailin Lu Bijun Xu Ningben Jin 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2021年第5期196-206,共11页
The explosive increase of construction and demolition waste(CDW) caused the insufficient source separation and emergency disposal at domestic waste landfills in many developing countries. Some organic fractions were i... The explosive increase of construction and demolition waste(CDW) caused the insufficient source separation and emergency disposal at domestic waste landfills in many developing countries. Some organic fractions were introduced to the CDW landfill process and resulted in serious odor pollution. To comprehensively explore the impacts of organic matters on odor emission patterns, five CDW landfills(OIL), with organic matters/inert CDW components(O/I) from 5% to 30%, and the control group only with inert components(IL) or organics(OL) were simulated at the laboratory. The chemical and olfactive characters of odors were evaluated using the emission rate of 94 odorants content(ER_(total)), theory odor concentration(TOC_(total)), and e-nose concentration(ER_(ENC)), and their correlations with waste properties were also analyzed. It was found that the main contributors to ER_(total)(IL: 93.0% NH_(3);OIL: 41.6% sulfides, 31.0% NH_(3), 25.9% oxygenated compounds) and TOC_(total)(IL: 64.1% CH_3SH, 28.2% NH_(3);OIL: 71.7% CH_(3)SH, 24.8% H_(2)S) changed significantly. With the rise of O/I, ER_(total), TOC_(total), and ER_(ENC) increased by 10.9, 20.6, and 2.1 times, respectively. And the organics content in CDW should be less than 10%(i.e., DOC < 101.3 mg/L). The good regressions between waste properties(DOC, DN, pH) and ER_(total),( r = 0.86, 0.86,-0.88, p < 0.05), TOC_(total),( r = 0.82, 0.79, -0.82, p < 0.05) implied that the carbon sources and acidic substances relating to organics degradation might result in that increase. Besides, the correlation analysis results( ER_(ENC) vs. TOC_(total,, r = 0.96, p < 0.01;vs. ER_(ENC), r = 0.86, p < 0.05) indicated that e-nose perhaps was a reliable odor continuous monitoring tool for CDW landfills. 展开更多
关键词 Construction and demolition waste LANDFILLS emission rate Volatile odor compounds Organic matters Theory odor concentration
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